Film manufacturing method

Abstract

To provide manufacturing method for film that can reduce liquid scattering while maintaining a liquid film that reduces wear between components.SOLUTION: The present invention is a manufacturing method for film that includes a process of stretching film by using a tenter device equipped with a mechanism in which bearings run along rails, light is irradiated onto a liquid film existing on the surface of the rails, the reflected light is detected by a sensor, the thickness of the liquid film is measured, and the thickness of the liquid film is adjusted.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a film having a step of stretching the film using a tenter device including a mechanism in which a bearing travels along a rail.

Background Art

[0002] In a device having a mechanism in which a plurality of members come into contact with each other, in order to reduce wear of each member during its operation, it is common to form a liquid film (mainly an oil film) between the members. At this time, if the thickness of the liquid film is too small, the effect of reducing wear of the members becomes insufficient, and damage to the device is accelerated, resulting in a decrease in its durability. Conversely, if the thickness of the liquid film is too large, the liquid scatters around the members as the device operates. Therefore, if the device is a production device for an object, there is a risk that the liquid adheres to the product and impairs its quality. That is, when using such a device, it is important to measure the thickness of the liquid film between the members in contact with each other and check whether it is within an appropriate range, and methods for measuring the thickness of the liquid film have also been studied.

[0003] As a method for measuring the thickness of the liquid film between members, for example, a method of analyzing the luminance distribution of interference fringes generated by irradiating light and measuring the thickness based on the calculation result of the obtained wavelength (Patent Document 1), or a method of measuring the thickness by a spectroscopic interference method using curve fitting for the reflected light obtained by irradiating light (Patent Document 2), etc., various methods have been proposed (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, although the inspection apparatus disclosed in Patent Document 1 can measure the oil film between a spherical member and a corresponding member, it cannot be applied when measuring the oil film between members of a different shape.

[0006] In addition, the quality impact of liquid splashing on the product is significant, and the required quality is becoming stricter year by year. Therefore, it is necessary to more strictly control the thickness of the liquid film. Here, since the inspection apparatus disclosed in Patent Document 2 has difficulty detecting a liquid film thickness of 2 μm or less, precise adjustment of the liquid film cannot be achieved.

[0007] The present invention aims to solve the above problems. That is, an object of the present invention is to provide a method for manufacturing a film capable of reducing liquid splashing while maintaining a liquid film that reduces wear between members.

Means for Solving the Problems

[0008] The present invention for solving the above problems is a method for manufacturing a film having a step of stretching the film using a tenter device provided with a mechanism in which a bearing travels along a rail, irradiating light on a liquid film present on the surface of the rail, detecting the reflected light obtained by the irradiation with a sensor, measuring the thickness of the liquid film, and adjusting the liquid film thickness. Further, the method for manufacturing a film can also be in the following aspects. (1) A method for manufacturing a film having a step of stretching the film using a tenter device provided with a mechanism in which a bearing travels along a rail, the method having a liquid film on the surface of the rail, irradiating light on the liquid film present on the surface of the rail, detecting the reflected light obtained by the irradiation with a sensor, and measuring the thickness of the liquid film by analyzing the reflected light by a spectroscopic interference method using curve fitting, the method for manufacturing a film being characterized in that the liquid film thickness is 0.5 μm or more and 2.0 μm or less. (2) The liquid film on the surface of the rail is formed by discharging liquid from the liquid supply port existing on the rail, and the discharge of the liquid is performed by adjusting the liquid supply amount, the film manufacturing method according to (1). (3) The liquid film on the surface of the rail is formed after lubricating oil is discharged from four or more liquid supply ports existing on the rail and then the bearing travels on the rail, and the discharge of the lubricating oil is discharged in a fixed amount by a gear pump, the film manufacturing method according to (1) or (2). (4) The surface roughness of the rail is 0.5 μm or less, and the surface roughness of the bearing is 0.5 μm or less, the film manufacturing method according to any one of (1) to (3). (5) Characterized by continuously measuring the thickness of the liquid film, the film manufacturing method according to any one of (1) to (4).

Advantages of the Invention

[0009] According to the present invention, it is possible to provide a film manufacturing method capable of reducing liquid scattering while maintaining a liquid film that reduces wear between members.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0011] The method for manufacturing a film of the present invention is a method for manufacturing a film having a step of stretching the film using a tenter device provided with a mechanism in which a bearing travels along a rail, wherein light is irradiated onto a liquid film present on the surface of the rail, reflected light obtained is detected by a sensor, the thickness of the liquid film is measured, and the liquid film thickness is adjusted. Hereinafter, the present invention will be specifically described.

[0012] FIG. 1 is a side view of one aspect of a liquid film thickness measuring device that can be used in the method for manufacturing a film of the present invention, which is installed in a film forming apparatus. An example of a liquid film thickness measuring device for measuring the thickness of a liquid film 2 present on the surface of a member (rail) 1 is shown. Reference numeral 3 denotes an analyzer main body incorporating at least a light source (not shown) and a spectroscope (not shown), and reference numeral 4 denotes a sensor having a tip of an optical fiber that at least irradiates and detects light and incorporating a lens (not shown) capable of adjusting the light irradiation area. The light sent through an optical fiber 5 connected to the light source incorporated in the analyzer main body 3 is irradiated onto the liquid film 2 on the surface of the member 1 as irradiation light 6 after the irradiation area is adjusted by the lens incorporated in the sensor 4. Therefore, the light source incorporated in the analyzer main body 3, the optical fiber 5 connected to the light source, and the lens incorporated in the sensor 4 constitute the light irradiation means 7 in the present invention, including the irradiation light 6.

[0013] FIG. 2 is a schematic plan view showing a film, a clip device, and a clip rail, which are examples of a tenter device that can be used in the film manufacturing method of the present invention. The tenter device of FIG. 1 includes a plurality of clip devices 9 driven by sprockets 8 and a chain (not shown) on both sides. In the tenter device, both end portions in the width direction of the film 10 are gripped by clips (shown in FIG. 2) attached to the clip device 9 that travels on the clip rail 11, and the film 10 gripped by the clips travels in the longitudinal direction (arrow direction) in the tenter device as the clip device 9 travels. At this time, the film 10 is stretched in the width direction by widening the interval between the clip rails 11 on both sides. Although not shown in FIG. 1, the tenter device may have a preheating zone for preheating the film 10 before the stretching zone, a heat fixing zone for performing heat treatment on the film 10 after the stretching zone, and a cooling zone for cooling the film 10 after heat fixing. Note that the width direction refers to the direction orthogonal to the longitudinal direction within the film plane.

[0014] FIG. 3 is an enlarged cross-sectional view taken along the line I-I' in FIG. 2. Reference numeral 12 indicates a clip that grips the end portion in the width direction of the film 10. The clip 12 is attached to a connecting member 13, and the clip 12 and the connecting member 13 constitute the clip device 9. A plurality of bearings 15 are disposed in the connecting member 13, and by allowing the plurality of bearings 15 to travel on the clip rail 11, the clip device 9 can travel smoothly along the clip rail 11. Further, by forming a liquid film 14 on the surface of the clip rail 11, wear of the clip rail 11, the bearings 15, etc. can be reduced when the clip 12 of the clip device 9 travels on the clip rail 11 while gripping the film 10. In the example shown in FIG. 2, one clip device 9 includes a total of six bearings 15 so as to sandwich the clip rail 11 from above, below, left, and right. However, the position and number of the bearings 15 are not limited to the above configuration as long as the clip device 9 can travel smoothly.

[0015] The surface roughness of the clip rail 11 and the bearing 15 is preferably 0.5 μm or less. The method of setting the surface roughness of the clip rail 11 and the bearing 15 within the above range is not particularly limited. When the clip rail 11 and the bearing 15 are new, their surface roughness may be 1 μm or more. Since the surface roughness of the clip rail 11 and the bearing 15 wears and the surface roughness decreases when they are used, the clip rail 11 and the bearing 15 that have been used for at least one month or more are preferably used.

[0016] When forming the liquid film 2 at the location where the plurality of members rub against each other, if the liquid becomes excessive, the liquid will scatter. Therefore, from the perspective of reducing the scattering of the liquid, the thickness of the liquid film needs to be 0.5 μm or more and 2.0 μm or less, and more preferably 0.5 μm or more and 1.5 μm or less. By setting the thickness of the liquid film below the above upper limit, the scattering of the liquid film components caused by another member running on the member on which the liquid film is formed can be reduced. Also, by setting the thickness of the liquid film above the above lower limit, the effect of reducing the wear of the member becomes sufficient, and the durability of the device can be improved.

[0017] In the present invention, the method of forming the liquid film and adjusting its thickness is not particularly limited. However, the liquid film on the surface of the rail is formed by discharging the liquid from the liquid supply port existing on the rail, and preferably, the discharge of the liquid is performed by adjusting the supply amount of the liquid. Also, after lubricating oil is discharged from four or more liquid supply ports existing on the rail, the liquid film on the surface of the rail is formed by the bearing running on the rail, and preferably, the discharge of the lubricating oil is discharged in a fixed amount by a gear pump. Such a method will be described by taking a tenter device as an example. Four or more small holes (liquid supply ports) are opened on the bearing running surface of the clip rail of the tenter device to supply the liquid film. The holes are connected to the liquid tank, and a predetermined amount of liquid can be discharged through the gear pump. The discharge of the liquid is performed by adjusting the supply amount of the liquid.

[0018] The method for manufacturing the film of the present invention has, for example, a step of melt-extruding a raw material of the film with an extruder and then stretching it in at least one axial direction, and a step of stretching the film using a tenter device provided with a mechanism in which a bearing travels along a rail after the stretching step. The method for manufacturing a film is a method for manufacturing a film, which includes irradiating light onto a liquid film present on the surface of the rail, detecting reflected light obtained by the irradiation with a sensor, measuring the thickness of the liquid film by analyzing the reflected light by a spectroscopic interference method using curve fitting, and adjusting the liquid film thickness. By adopting such an aspect, it becomes possible to manufacture a film while reducing the scattering of the liquid while maintaining a liquid film that reduces wear between members.

[0019] Hereinafter, the method for manufacturing the film of the present invention will be specifically described by taking a polyester film by a sequential biaxial stretching method as an example. However, this shows one embodiment of the present invention, and the present invention is not limited thereto.

[0020] First, pellets of a polyester resin are supplied to a raw material input section of an extruder, and the polyester resin is heated and melted. Then, the extrusion amount is made uniform with a gear pump or the like, and the melted polyester resin is extruded, and foreign substances, gelated products, etc. are removed through a filter. At this time, one extruder or a plurality of extruders may be used. When a plurality of extruders are used, the thermoplastic resin that has passed through the filter is fed into a laminating device. As the laminating device, a multi-manifold die, a feed block, a static mixer, etc. can be used, and these may be arbitrarily combined.

[0021] The type of the polyester resin is not particularly limited as long as the effects of the present invention are not impaired. For example, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene-2,6-naphthalate (PEN), polybutylene naphthalate (PBN), polytrimethylene terephthalate (PPT), polyethylene-p-oxybenzoate, poly-1,4-cyclohexylene dimethylene terephthalate (PCT), etc. can be used alone or in a mixture of two or more types. Further, each of the above polyester resins can also contain a copolymerization component within a range not impairing the effects of the present invention.

[0022] The molten polyester resin thus obtained is discharged in a sheet form from a die and cooled and solidified by a cooling drum to obtain an unoriented polyester sheet. In this step, it is preferable to enhance the adhesion to the cooling drum by the electrostatic printing method.

[0023] Subsequently, the unoriented polyester sheet is heated to a temperature equal to or higher than the glass transition temperature of the polyester resin by a method of passing it in contact with several rolls with temperature control or by heating with radiant heat of a heater such as an infrared heater, and is stretched in the longitudinal direction (longitudinal stretching) using the peripheral speed difference between the front and rear rolls, etc. The stretching ratio of this longitudinal stretching depends on the use of the film to be manufactured and the type of the polyester resin. When the polyester resin is PET, it is preferably 2 to 8 times. Further, the longitudinal stretching may be performed in one step or stepwise in two or more steps.

[0024] The uniaxially oriented polyester sheet obtained by longitudinal stretching is once cooled and then continuously stretched in the width direction (transverse stretching) by a tenter device to become a biaxially oriented polyester film. The uniaxially oriented polyester sheet has both ends in its width direction gripped by clips near the entrance of the tenter device, and the clips equipped with bearings travel along the clip rail and travel toward the exit of the tenter device. During this period, the uniaxially oriented polyester sheet is heated again to a temperature above the glass transition temperature of the polyester resin in the tenter device, stretched in the width direction as the rail along which the clips travel widens, and then heat-treated and cooled. The stretching ratio in the width direction depends on the use of the film to be manufactured and the type of polyester resin. When the polyester resin is PET, it is preferably 2 to 5 times. Also, when the polyester resin is PET, heat treatment can be performed at a relatively high temperature of 180°C to 250°C. By performing heat treatment, the dimensional stability when exposed to high temperatures during subsequent processing steps and when used as a final product is improved. Also, after heat treatment, the dimensional stability can be further improved by relaxing the biaxially oriented polyester film by 1% to 10% in at least one of the longitudinal direction and the width direction. Note that the process after transverse stretching may be performed in the same tenter device following transverse stretching or in a tenter device different from the tenter device that performed transverse stretching.

[0025] The biaxially oriented polyester film thus obtained is once wound as an intermediate product roll by a wide-width winder, then cut by a slitter to the required width and length, and wound again to become a final product.

[0026] Here, in the lateral stretching process, if the amount of lubricating oil discharged onto the clip rail is large, excessive lubricating oil adheres to the running bearing, and the lubricating oil scatters onto the film, deteriorating the film quality. Therefore, it is preferable to have a process of continuously measuring the lubricating oil on the clip rail side surface, feeding back the thickness of the liquid film, and adjusting the amount of lubricating oil discharged onto the rail. Also, the term "continuous" as used here means continuously measuring during film production, and the measurement period can be arbitrarily set by the user, such as 1 second or 1 minute, depending on the performance of the analyzer.

Example

[0027] Hereinafter, the present invention will be specifically described using examples. However, the present invention is not limited to the following examples.

[0028] (Measurement method) The measurement method was the same as the method shown in FIG. 1. Member 1 was a silicon wafer with a surface polished, liquid film 2 was a synthetic oil, and analyzer body 3 and sensor 4 were performed using the multi-channel spectrometer MCPD-9800 of Otsuka Electronics.

[0029] (Example) In a method for manufacturing a film having a step of stretching the film using a tenter device equipped with a mechanism in which a bearing travels along a rail on a machine, a liquid film is provided on the surface of the rail, and reflected light obtained by irradiating light onto the liquid film present on the surface of the rail is detected by a sensor, and the thickness of the liquid film is measured by analyzing the reflected light by a spectroscopic interference method using curve fitting. The reflected light obtained by irradiating light onto the liquid film present on the surface of the rail was detected by a sensor, and the reflected light was analyzed by a spectroscopic interference method using curve fitting to measure the thickness of the liquid film. The thickness of the liquid film measured by such measurement of the liquid film was 0.54 μm.

[0030] Note that as the member (rail), a silicon wafer with a surface polished (using a surface roughness of 0.5 μm or less) was used. As the liquid for forming the liquid film, synthetic oil was used. As a method for forming a liquid film on the silicon wafer which is the member (rail), first, the surface of each member (rail) was cleaned to remove metal powder, etc. in advance, and then, using a pipette, a certain amount of synthetic oil was discharged onto the silicon wafer, and the surface of the silicon wafer was repeatedly touched by hand to make it equivalent to the thickness of the oil film normally adjusted on the rail surface of the tenter device.

[0031] The film obtained by the above method was able to suppress the scattering of the liquid to the film and had good quality.

Industrial Applicability

[0032] According to the present invention, it is possible to provide a method for manufacturing a film capable of reducing the scattering of a liquid while maintaining a liquid film that reduces wear between members. By using the optical property measurement method of the present invention, since the scattering of the liquid to the film can be suppressed, the quality of the film can be improved.

Explanation of Signs

[0033] 1: Member (rail) 2: Liquid film 3: Analyzer main body 4: Sensor 5: Optical fiber 6: Irradiating light 7: Light irradiating means 8: Sprocket 9: Clip device 10: Film 11: Clip rail 12: Clip 13: Connecting member 14: Liquid film 15: Bearing

Claims

1. A method for manufacturing a film, comprising a step of stretching a film using a tenter device provided with a mechanism in which a bearing travels along a rail, wherein a liquid film is present on the surface of the rail, reflected light obtained by irradiating light on the liquid film present on the surface of the rail is detected by a sensor, and the thickness of the liquid film is measured by analyzing the reflected light by a spectroscopic interference method using curve fitting, and the liquid film thickness is 0.5 μm or more and 2.0 μm or less.

2. The method for manufacturing a film according to claim 1, wherein the liquid film present on the surface of the rail is formed by discharging liquid from a liquid supply port present on the rail, and the discharge of the liquid is performed by adjusting the liquid supply amount.

3. The method for manufacturing a film according to claim 1, wherein the liquid film present on the surface of the rail is formed by discharging lubricating oil from four or more liquid supply ports present on the rail and then the bearing travels on the rail, and the discharge of the lubricating oil is discharged in a fixed amount by a gear pump.

4. The method for manufacturing a film according to claim 1 or 2, wherein the surface roughness of the rail is 0.5 μm or less and the surface roughness of the bearing is 0.5 μm or less.

5. The method for manufacturing a film according to claim 1 or 2, wherein the thickness of the liquid film is continuously measured.

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