CN111512704A

CN111512704A - Method for manufacturing web, method for controlling electrification, and electrification control device

Info

Publication number: CN111512704A
Application number: CN201880083388.2A
Authority: CN
Inventors: 奥野将人; 渡边充
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2017-10-30
Filing date: 2018-10-29
Publication date: 2020-08-07
Also published as: EP3706515B1; EP3706515A4; JPWO2019088052A1; JP7347213B2; WO2019088052A1; EP3706515A1

Abstract

For example, a long polymer film or the like is not previously charged, and a coil material capable of controlling the amount of charge is manufactured. In a method for manufacturing a coil including a step of conveying a coil, a liquid is supplied to an interface between a roller for conveying the coil and the coil, and an amount of charge generated on a surface of the coil by frictional electrification between the roller and the coil is controlled. As the liquid, for example, a liquid that generates frictional electrification with the web is used, and the polarity of the frictional electrification is opposite to the electrification polarity generated on the surface of the web by the frictional electrification between the transport roller and the web.

Description

Method for manufacturing web, method for controlling electrification, and electrification control device

Technical Field

The present invention relates to a method for manufacturing a web capable of controlling a charge amount, a charge control method for controlling a charge amount of a web, and a charge control apparatus.

Background

Generally, when two substances rub against each other, static electricity is generated, and one of the two substances is relatively positively charged and the other is negatively charged. The tendency of a substance to be positively or negatively charged when the substance and another substance rub against each other is generally known as a charging sequence for each substance, and by referring to the charging sequence, it is possible to estimate which of the substances is positively charged when triboelectrification occurs between any two substances. An example of the charging sequence is shown in non-patent document 1.

For example, when a long web such as a polymer film is conveyed, the web is moved by rotating the conveying roller while supporting the web by the conveying roller, but static electricity is generated between the web and the conveying roller at this time, and the surface of the conveyed web is charged. If the charge amount of the surface of the web becomes large, a peeling discharge may occur between the web and the transport roller at a position where the web transported by the transport roller is separated from the transport roller (referred to as a roller peeling point). As a result, discharge marks are formed on the surface of the coil, which causes defects in the coil. For example, when a coil is coated, discharge marks cause coating unevenness. In addition, there is a problem that various kinds of dust are likely to adhere to the charged surface even if the peeling discharge is not generated.

As a technique for eliminating the electrification generated on the surface of the web by the frictional electrification, there is a technique using a static eliminator that generates ions in the air that neutralize the surface charge. However, when the static eliminator is used, a space for installing the static eliminator is required, and the static eliminator may not be installed due to the structure around the conveying roller. Since ions are generated by discharge in the static eliminator, the static eliminator cannot be disposed even in an environment requiring explosion prevention. Further, when the web conveyance speed is high or the distance from the roller peeling point to the charge remover is large, the charge removing capability is insufficient and the charge cannot be sufficiently removed. Further, since the transport roller is generally made of metal and has conductivity, ions for charge removal are absorbed by the transport roller, and the charge removal capability is lowered. When the surface of the web is charged not uniformly but in spots, the potential of the charged spots becomes significantly low, and therefore, the charge may not be sufficiently removed.

Patent document 1 discloses the following: the transport roller is configured by alternately arranging a positively charged substance and a negatively charged substance in the transport direction of the web due to frictional electrification with the web, and thus the web is not charged in most cases.

Patent document 2 discloses the following: in the web, a surface on the opposite side to the surface charged by friction is given a charge of a polarity opposite to the triboelectrification, and the triboelectrification charge is neutralized by the charge of the opposite polarity.

Patent document 3 discloses the following: before the contact with the roller, a charge having a polarity opposite to that of the charge caused by frictional electrification is imparted to the surface of the web in contact with the roller in advance.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 62-131500

Patent document 2: japanese patent No. 5885869

Patent document 3: japanese laid-open patent publication No. 10-15812

Non-patent document

Non-patent document 1: gexishi, "tape measurement values に and ぼす factors (various factors affecting the measurement value of charging)", polymer society of society, polymer society, 1967, volume 16, 179, p.323-329

Disclosure of Invention

Problems to be solved by the invention

However, in the technique of patent document 1, since the coil is charged in microscopic observation, there is still a possibility that peeling discharge occurs, and it is difficult to actively control the charge amount on the surface of the coil.

In the method of patent document 2, the sum of the charge amounts on both the front surface and the back surface appears to be zero and uncharged, but actually, there is a charge on each surface, which causes coating unevenness in a coating step, which is a subsequent step, for example. In a state where electric charges exist on both the front surface and the back surface, if one surface is brought into contact with the metal roller and grounded, a potential based on the electric charges of the other surface is generated, and there is a possibility that dust in the air is attracted.

In the method of patent document 3, since the web before contact with the roller is at a high potential, there is a possibility that dust is adsorbed or discharge is caused when the web contacts with the roller.

As described above, in the technique for preventing electrification of the web conveyed by the conveyance roller, the technique using the static eliminator may not be applicable, and may cause a lack of static eliminating capability. The technique described in patent document 1 may not sufficiently prevent peeling discharge. The techniques described in patent documents 2 and 3 are techniques for imparting a charge having a polarity opposite to that of the charge generated by triboelectrification in advance, but have problems such as dust adsorption and discharge due to the imparted charge. Although it can be said that prevention of electrification of the web is one of the methods for controlling the electrification amount of the web, a general technique for controlling the electrification amount of the web by a method other than the charge addition is not known.

An object of the present invention is to provide a method of manufacturing a web, a method of controlling charging of a web, and a charging control apparatus, which are capable of controlling the charging amount of the web without applying a charge to the web in advance.

Means for solving the problems

The method for manufacturing a coil material of the present invention includes a conveying step of conveying the coil material, and includes the steps of: a liquid is supplied to an interface between a transport roller for transporting a web and the web, and an amount of charge generated on a surface of the web by frictional electrification between the transport roller and the web is controlled.

The charging control method of the present invention is a charging control method for controlling a charging amount of a web conveyed by a conveying roller, wherein a liquid is supplied to an interface between the conveying roller for conveying the web and the web, and the charging amount generated on a surface of the web due to frictional electrification between the conveying roller and the web is controlled.

The electrification control device of the present invention controls the electrification amount of a conveyed web, and comprises: a conveying roller that conveys the web; and a supply unit that supplies a liquid to an interface between the transport roller and the web, and controls an amount of charge generated on a surface of the web by frictional electrification between the transport roller and the web by the liquid.

Triboelectrification can occur not only between solids but also between solids and liquids. In the present invention, in order to control the charge amount of the surface of the web after being conveyed by the conveying roller, a liquid for controlling the charge amount is supplied to the interface of the conveying roller conveying the web and the web. By controlling the amount of liquid supplied to the interface, the amount of charge generated on the surface of the web can be controlled. Since frictional electrification is also generated between the web and the liquid, the amount of charge on the surface of the web can be controlled by combining frictional electrification between the web and the liquid and frictional electrification between the web and the transport roller. In particular, by using, as the liquid, a triboelectric liquid that generates a polarity opposite to a charging polarity generated on the surface of the web due to triboelectric charging between the transport roller and the web, it is possible to reduce or prevent charging on the surface of the web. What kind of liquid should be used may be determined based on the charging sequence described above depending on the material of the web and the material of the surface of the transport roller. Further, if the amount of liquid supplied to the interface between the transport roller and the web is changed, the magnitude of frictional electrification generated between the web and the liquid is also changed, and therefore the amount of electrification of the web can be more finely controlled by controlling the amount of liquid supplied to the interface.

In the present invention, the roll material is, for example, a long polymer film or an electrically insulating film. As a method of supplying the liquid at the interface of the conveying roller and the web, the liquid may be directly supplied to the interface from the entering direction of the web with respect to the interface, or the liquid may be sprayed toward the surface of the rotating conveying roller. The liquid sprayed onto the surface of the transport roller is provided to the interface of the transport roller and the web in conjunction with the rotation of the transport roller. As a method of supplying the liquid, a method of spraying can reduce the amount of liquid consumed as compared with a method of supplying the liquid directly to the interface, and can finely control the amount of the liquid supplied. In order to control the amount of charge in the width direction of the web (the direction perpendicular to the transport direction), the transport roller may be divided into a plurality of regions along the longitudinal direction of the transport roller, and the amount of liquid supplied may be controlled for each of the divided regions.

Effects of the invention

According to the present invention, it is possible to manufacture a coil material capable of controlling the amount of charge without applying a charge to the coil material in advance, and to control the amount of charge of the coil material.

Drawings

Fig. 1 is a diagram showing a configuration of a charging control device according to an embodiment of the present invention.

Fig. 2 is a diagram showing a configuration for controlling the charge amount of a wide web.

Detailed Description

Next, embodiments of the present invention will be described with reference to the drawings. Fig. 1 shows a charging control apparatus according to an embodiment of the present invention. The charging control device is used when the coil is manufactured by the manufacturing method according to the present invention.

The electrification control apparatus shown in fig. 1 is configured to be used in a step of conveying a web 10, and includes: a conveying roller 20 that conveys the web 10; and a spray nozzle 30 disposed opposite to the surface of the conveyance roller 20 at a position opposite to the position on the conveyance roller 20 where the web 10 is in contact.

Examples of the roll 10 include, but are not limited to, a film for magnetic material, a film for release, a film for capacitor, a film for battery separator, and the like. In particular, in the case of a film for a magnetic material, a release film, or a film for a battery separator, it is effective from the viewpoint of preventing coating unevenness when a final product is obtained through a coating step. In the case of a battery separator film with strict foreign matter management, it is effective from the viewpoint of preventing adhesion of dust and the like due to static electricity.

In an embodiment of the present invention, the conveying step is a step of: the apparatus includes at least one rotating feed roller for feeding the web by a frictional force generated between the feed roller and the web in a state where the feed roller is in contact with the web. The transport may be performed by providing other rotating rollers in front of and behind the transport roller, or may be performed by holding the end of the roll by a traveling gripper or the like.

The spray nozzle 30 is an atomizer that sprays the liquid b for controlling electrification onto the rotating conveyance roller 20, and functions as a supply unit that supplies the liquid b for controlling electrification to the interface between the conveyance roller 20 and the web 10. That is, the supply unit may be an atomizer that sprays liquid onto the rotating transport roller. The spray nozzle 30 is supplied with a liquid b for electrification control, and compressed air a is also supplied to spray the liquid b for electrification control. The spray nozzle 30 is covered with a nozzle cover 40 in order to prevent the liquid b for electrification control from scattering to an undesired position. The nozzle cover 40 has a slit 41 extending in the longitudinal direction of the conveyance roller 20 formed at a position facing the conveyance roller 20, and the liquid b for controlling electrification discharged from the spray nozzle 30 reaches the conveyance roller 20 through the slit 41. The width of the slit 41 (length along the rotational direction of the conveying roller 20) can be adjusted, for example, within a range of 10mm to 30mm, and the gap (clearance) between the position of the slit 41 and the surface of the conveying roller 20 is, for example, about 2 mm. The spray can be performed by one spray nozzle 30 to an area of, for example, about 30cm in the longitudinal direction of the feed roller 20.

In the charging control apparatus shown in fig. 1, a potentiometer 50 is disposed at a position downstream of the transport roller 20 in the transport direction of the web 10, and the potentiometer 50 measures the surface potential of the surface of the web 10 that is in contact with the transport roller 20. Although the potentiometer 50 is not essential, as will be understood from the later-described embodiment, since the surface potential of the web 10 changes and the charge amount changes according to the supply amount of the charge controlling liquid b, the charge amount of the web 10 can be controlled more accurately by providing the potentiometer 50 and controlling the supply amount of the charge controlling liquid b based on the measurement value thereof. The surface of the web 10 conveyed from the conveying roller 20 toward the downstream side may be wetted with the electrification controlling liquid b, but the electrification controlling liquid b can be removed by, for example, air blowing, heat drying, scraping with a nip roller, or the like.

Next, control of the charge amount using this charge control device will be described. When the liquid b for electrification control is sprayed from the spray nozzle 30 toward the conveyance roller 20 and the conveyance roller 20 is rotated to convey the web 10, the sprayed liquid b for electrification control is continuously supplied to the interface of the web 10 and the conveyance roller 20. As a result, frictional electrification is generated between the conveying roller 20 and the web 10, and frictional electrification is also generated between the supplied liquid and the web 10. If the two frictional electrification portions have the same polarity with respect to the web 10, the absolute value of the surface potential of the web 10 becomes large, and the charge amount of the web 10 becomes large. If the polarity is opposite to each other, the electric charge generated by the frictional electrification between the transport roller 20 and the web 10 is neutralized by the frictional electrification between the liquid b for electrification control and the web 10, and if the frictional electrification between the liquid b for electrification control and the web 10 is of an appropriate magnitude, the frictional electrification cancel each other out, and the electrification amount of the web 10 becomes extremely small. Therefore, according to the charging control device of the present embodiment, the charging amount of the web 10 can be controlled, and particularly, if a liquid that generates triboelectrification with the web (a polarity opposite to the charging polarity generated on the surface of the web due to the triboelectrification of the transport roller and the web) is used as the liquid b for charging control and the supply amount thereof is controlled, the charging amount of the web 10 can be made almost zero.

The type of liquid to be used as the liquid b for controlling charging can be determined based on the charging sequence in consideration of the material of the surface of the transport roller 20 according to the target charging amount and the material of the web 10, but is preferably selected within a range in which the properties of the web 10 are not changed. For example, when the coil 10 is a polyethylene film, examples of the surface material of the transport roller 20 that is likely to generate positive frictional electrification include silicone rubber and hard chrome plating, and examples of the liquid that is likely to generate negative frictional electrification include water. On the other hand, the surface material of the transport roller 20 that is likely to generate negative frictional electrification with respect to the polyethylene film is, for example, glass, and the liquid that is likely to generate positive frictional electrification is, for example, a halogen-based solvent such as trichlorobenzene or methylene chloride.

The width of the web 10 (i.e., the direction perpendicular to the conveying direction) is sometimes wider than the width of the liquid b for electrification control that can be sprayed from one sprayer as a supply unit. In such a case, if only one atomizer is used, the electrification amount control can be performed only on a part of the web 10. Fig. 2 shows the arrangement of the sprayers (spray nozzles 30) in the electrification control device corresponding to the wide web 10. For ease of illustration, the web 10 is not shown in FIG. 2.

In the electrification control apparatus shown in fig. 2, similarly to the apparatus shown in fig. 1, the liquid b for electrification control is sprayed from the spray nozzle 30, and the liquid b for electrification control is supplied to the interface between the web 10 and the transport roller 20, and the electrification amount of the web 10 is controlled, here, water is used as the liquid b for electrification control, and it is assumed that the length of the transport roller 20 is longer than the width of the web 10, in the electrification control apparatus shown in fig. 2, a plurality of (here, three) spray nozzles 30 are prepared as sprayers, these spray nozzles 30 are arranged in one nozzle cover 40 along the longitudinal direction of the transport roller 20, air a for spraying water is supplied to the plurality of spray nozzles 30 in common, slits 41 of the nozzle cover 40 are provided so as to face the transport roller 20 over substantially the entire length in the longitudinal direction of the transport roller 20, in the illustrated example, the transport roller 20 is divided into three regions (each region of L, C, and R in the longitudinal direction thereof), water for spraying is supplied via the pressure reducing valve 31, and the three regions (32 to 34) and L to 3534 are branched from the outlet side of the pressure reducing valve 31, and the nozzle 32 to 34, and the nozzle 32 to L, 32, 34, and the flow meter 32.

In the configuration shown in fig. 2, when the feed roller 20 is divided into a plurality of zones in the longitudinal direction thereof by controlling the valve 35, the amount of supplied water can be controlled for each of the divided zones, whereby the amount of electrification in the width direction of the web 10 can be controlled, and particularly, since the flow meters 36 are provided in correspondence with the zones L, the zones C, and the zones R, respectively, the amount of electrification can be controlled with high accuracy for each of the zones L, the zones C, and the zones R by controlling the opening degree of the valve 35 based on the measurement value of the flow meter 36.

Examples

The present invention will be described in more detail below with reference to examples.

[ example 1]

The device shown in fig. 1 is assembled. Here, a soft polyethylene sheet (manufactured by KOKUGO K.K.) having a thickness of 30 μm was used as the coil 10, and a metal roller having a diameter of 150mm and a hard chrome-plated surface was used as the feed roller 20. A two-fluid nozzle (model: SCBIMV80005S) manufactured by Kabushiki Kaisha was used as the spray nozzle 30 as the atomizer. Tap water is used as the liquid b for electrification control, and the tap water and air a are supplied to the spray nozzle 30, whereby water can be sprayed to the transport roller 20. The feed roller 20 was rotated and the web 10 was fed at a speed of 30 m/min. The surface potential of the web 10 is measured by a potentiometer 50 provided on the downstream side of the conveyance roller 20 while changing the presence or absence of water spray and the flow rate of water spray. The results are shown in Table 1.

As is apparent from table 1, when water is not sprayed, the surface potential of the web 10 is about +15kV and positive, but when water is sprayed, the surface potential changes in a negative direction, when the spray flow rate of water is 7m L/min, the surface potential decreases to about +8kV, and when the spray flow rate is 11m L/min, the surface potential becomes almost 0 kV., that is, when the spray flow rate of water is 10m L/min to 12m L/min, frictional electrification of the web 10 can be prevented, and when the spray flow rate is further increased to 16m L/min, the surface potential can be decreased to-17 kV., and the surface potential of the web 10, that is, the electrification amount can be controlled by controlling the spray flow rate, that is, the amount of water supplied to the interface between the feed roll 20 and the web 10.

[ Table 1]

[ example 2]

As a result, as shown in table 2, it is understood from table 2 that the surface potential of the web 10 is about-9 kV and negative when the liquid is not sprayed, but the surface potential changes in the positive direction when the liquid is sprayed, the surface potential moves to the positive side and to about-5 kV when the spray flow rate of the liquid is 10m L/min, and the surface potential becomes almost 0 kV. when the spray flow rate of the liquid is 15m L/min, that is, the frictional electrification of the web 10 can be prevented by setting the spray flow rate of the liquid to 14m L/min to 16m L/min, and the frictional electrification of the web 10 can be controlled by setting the spray flow rate to 20m L/min, and the surface potential moves to +8 kV. when the spray flow rate of the liquid is further increased to 20m 3538/min, even when the web 10 is negatively electrified due to frictional electrification with the transport roller 20.

[ Table 2]

Industrial applicability

According to the present invention, there are provided a method of manufacturing a coil, a method of controlling electrification, and an apparatus for controlling electrification, which can manufacture a coil capable of controlling an amount of electrification without giving an electric charge to the coil in advance, and which can control the amount of electrification of the coil.

Although the present invention has been described in detail with reference to the specific embodiments, it is apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.

The present application is based on the japanese patent application (japanese patent application No. 2017-209140), filed on 30/10/2017, the contents of which are incorporated in the present specification by reference.

Description of the reference symbols

10: a coil stock; 20: a conveying roller; 30: a spray nozzle; 40: a nozzle cover; 50: a potentiometer; a: air; b: a liquid for electrification control; w: and (3) water.

Claims

1. A method for manufacturing a coil material, comprising a step of transporting the coil material, wherein,

the manufacturing method comprises the following steps: a liquid is supplied to an interface between a transport roller for transporting the web and the web, and an amount of charge generated on a surface of the web by frictional electrification between the transport roller and the web is controlled.

2. The manufacturing method according to claim 1,

the liquid is a liquid that generates frictional electrification between the liquid and the web, and the frictional electrification has a polarity opposite to a charging polarity generated on the surface of the web by the frictional electrification between the transport roller and the web.

3. The manufacturing method according to claim 1 or 2,

controlling an amount of charge generated on a surface of the web by controlling an amount of the liquid supplied to the interface.

4. The manufacturing method according to claim 3,

the transport roller is divided into a plurality of regions along a longitudinal direction of the transport roller, and the amount of the liquid is controlled for each of the divided regions.

5. A charging control method for controlling a charging amount of a web conveyed by a conveying roller,

a liquid is supplied to an interface between a transfer roller for transferring a web and the web, and an amount of charge generated on a surface of the web by frictional electrification between the transfer roller and the web is controlled.

6. The charging control method according to claim 5,

7. The charging control method according to claim 5 or 6,

8. The charging control method according to claim 7,

9. A charging control device for controlling the charging amount of a web to be conveyed,

the charging control device comprises:

a conveying roller that conveys the web; and

a supply unit that supplies a liquid to an interface of the transport roller and the web,

the amount of charge generated on the surface of the web by frictional electrification between the transport roller and the web is controlled by the liquid.

10. The charging control apparatus according to claim 9,

11. The charging control apparatus according to claim 9 or 10,

the amount of charge generated on the surface of the web is controlled by controlling the amount of the liquid supplied to the interface by the supply unit.

12. The charging control apparatus according to claim 11,

the conveying roller is divided into a plurality of regions along the longitudinal direction of the conveying roller, and the supply unit is provided for each of the divided regions.

13. The charging control apparatus according to any one of claims 9 to 12,

the supply unit is an atomizer that sprays the liquid to the rotating transport roller.