TWI828823B - Method for manufacturing optical film and apparatus for manufacturing optical film - Google Patents

Abstract

The present invention provides a method for manufacturing optical film and an apparatus for manufacturing optical film capable of being performed with stable steps, having stable quality, and further capable of reducing material cost. A method for manufacturing an optical film 4 according to one embodiment of the present invention is a method for manufacturing an optical film by applying N treatments (N is an integer of 1 or more) on a long film 2, wherein the N treatments are performed while the film is transported, and positions of first ends and second ends 2a, 2b of the film are continuously acquired at each of a plurality of locations 20 during the transportation. When the distance between a reference position B in the width direction of the film and the position of a first end is taken as the first width, and the distance between the reference position and a second end is taken as the second width, the reference position is calculated based on a first acquiring result at positions of a first end and a second end at an upstream location among two locations selected from a plurality of locations, and the difference of a second change rate of the second width from a first change rate of the first width is calculated based on a second acquiring result at positions of a first end and a second end at a downstream location among the two locations and the first acquiring result.

Description

Optical film manufacturing method and optical film manufacturing device

The present invention relates to an optical film manufacturing method and an optical film manufacturing device.

Generally, an optical film is manufactured by carrying out at least one process for imparting desired optical characteristics while conveying the film. For example, when the optical film is a polarizing film, at least one treatment for imparting linear polarization characteristics as optical characteristics is performed on the film. When an optical film is manufactured as described above, the width of the film will vary during the process of manufacturing the optical film from the film. It is known that when a film is conveyed, the rate of change of the film width on the upstream side and the film width on the downstream side is called a neck-in rate (see Patent Document 1). In the production of optical films During the process, when the shrinkage ratio of the film deviates from the preset allowable range (management width), the film may break or the film thickness may deviate from the desired thickness. Therefore, in order to properly manufacture optical films, shrinkage is necessary. Amplitude management is crucial.

[Prior technical literature]

[Patent Document]

Patent Document 1: Japanese Patent Application Publication No. 8-226811

Generally, the reduction ratio is calculated for the entire width of the film. However, even if the reduction ratio of the entire width of the film is within the desired range, there is still a width from the reference position in the width direction of the film to one end of the film (hereinafter referred to as "the first Deviation occurs in the change in width from the reference position to the other end of the film (hereinafter referred to as the "second width"). In this case, for example, the load exerted on the conveyance roller which conveys a film becomes locally large, and equipment failure may easily occur. When equipment is missing, defects such as the optical film becoming defective or the film breaking may occur. When deviations occur in the changes in the first width and the second width, the film thickness in the width direction is likely to deviate from the desired state. As a result, if the film thickness deviates from the desired state, an optical film having desired uniform optical properties cannot be obtained. Therefore, the material used for manufacturing the optical film is wasted, resulting in an increase in material cost.

Therefore, an object of the present invention is to provide an optical film manufacturing method and an optical film manufacturing device that can be implemented in stable steps, have stable quality, and can also reduce material costs.

A method of manufacturing an optical film according to one aspect of the present invention is a method of manufacturing an optical film by performing N processes (N is an integer of 1 or more) on a long film; the method is carried out while conveying the film. The aforementioned N processes; in the aforementioned transportation, the positions of the first end portion and the second end portion in the width direction of the aforementioned film are continuously obtained at a plurality of locations; and the aforementioned ends in the width direction of the aforementioned film are When the distance between the reference position and the position of the first end is set as the first width, and the distance between the reference position and the second end is set as the second width, the distance between the reference position and the position of the first end is set as the second width. The reference position is calculated based on the first acquisition result of the positions of the first end portion and the second end portion in the upstream portion among the upstream portions, and the reference position is calculated based on the first acquisition result and the position of the downstream portion among the two locations. of The second acquisition result of the positions of the first end portion and the second end portion is to calculate the difference between the first change rate of the first width and the second change rate of the second width.

An optical film manufacturing apparatus according to another aspect of the present invention is provided with: N processing units (N is an integer equal to or greater than 1) for performing at least a process of imparting optical properties to the film; and a transport mechanism for transporting the film; The plurality of position acquisition devices are arranged at a plurality of positions on the conveyance mechanism, and continuously acquire at the plurality of positions the first end and the second end in the width direction of the film being conveyed by the conveyance mechanism. The position of the two ends; and the calculation part are based on the distance between the reference position in the width direction of the film and the position of the first end being the first width, and the distance between the reference position and the second end in the film. When the distance between the two position acquisition devices is set to the second width, the position of the first end and the second end of the upstream position acquisition device among the two position acquisition devices selected from the plurality of position acquisition devices are The reference position is calculated based on the first acquisition result and the position of the first end and the second end of the downstream position acquisition device among the two position acquisition devices. The second result is obtained, and the difference between the first change rate of the first width and the second change rate of the second width is calculated.

In the above-mentioned manufacturing method and the above-mentioned manufacturing apparatus, the positions of the first end portion and the second end portion of the conveyed film are continuously obtained at a plurality of locations. The first change rate and the second change rate of the first width of the film are calculated based on the first acquisition result and the second acquisition result belonging to the acquisition results of two locations (the upstream location and the downstream location) selected from among the plurality of locations. The difference between the second change rate of the two widths. Therefore, the difference between the first change rate and the second change rate can be obtained during film transportation. Therefore, when the difference between the first change rate and the second change rate exceeds the allowable range, defects can be avoided by, for example, interrupting the manufacturing of the optical film or adjusting the manufacturing conditions to within the allowable range. In addition, it can be managed without exceeding the allowable range, thus preventing defects before they occur. As a result, it is difficult to produce a defective optical film, and defects such as cutting can be suppressed. lose. Therefore, the optical film can be produced in a stable process. Furthermore, optical films of stable quality can be produced uniformly. Furthermore, the material cost of the optical film can also be reduced.

In the said manufacturing method, the said reference position in the said upstream part may be the center position in the width direction of the said film in the said upstream part.

In the manufacturing apparatus, the reference position in the arrangement location of the upstream side position acquisition device may be the center position in the width direction of the film obtained from the first acquisition result in the arrangement location.

In the manufacturing method, the difference between the first change rate and the second change rate in at least one combination of the upstream site and the downstream site selected from the plurality of sites may be 1.0% or less. Alternatively, in the aforementioned manufacturing method, the difference between the aforementioned first change rate and the aforementioned second change rate may be 1.0 in all combinations of the plurality of combinations of the aforementioned upstream portion and the aforementioned downstream portion selected from the aforementioned plurality of portions. %the following.

In the manufacturing apparatus, the difference between the first change rate and the second change rate in at least one combination of the upstream position acquisition device and the downstream position acquisition device selected from the plurality of position acquisition devices is also It can be less than 1.0%. Alternatively, in the manufacturing apparatus, in all combinations of a plurality of combinations of the upstream side position acquisition device and the downstream side position acquisition device selected from the plurality of position acquisition devices, the first change rate and the second change rate are The difference in change rates may be 1.0% or less.

In the aforementioned manufacturing method, the aforementioned upstream location may be a location before one of the aforementioned N processes is performed, and the aforementioned downstream location may be a location after the aforementioned one of the treatments is performed.

In the manufacturing apparatus, the upstream position acquisition device may be arranged before one of the N processing units, and the downstream position acquisition device may be arranged after the one processing unit.

The aforementioned first width and the aforementioned second width of the film can easily change when the film is processed. Therefore, in the above-described configuration, the difference between the first change rate and the second change rate can be calculated at a location where the first width and the second width are easy to change. The first change rate and the second change rate can also be calculated.

In the aforementioned manufacturing method, the aforementioned N processes may include the i-1th process, the i-th process, and the i+1th process (i is an integer equal to or greater than 2), and the aforementioned upstream portion may be located at the i-1th process. between the location of the i-th process and the location of the i-th process, and the downstream location is between the location of the i-th process and the location of the i+1-th process.

In the manufacturing apparatus, the N processing units may include an i-1th processing unit, an i-th processing unit, and an i+1th processing unit (i is an integer of 2 or more), and the upstream side position acquisition The device is arranged between the i-1th processing unit and the i-th processing unit, and the downstream position acquisition device is arranged between the i-th processing unit and the i+1th processing unit.

The aforementioned first width and the aforementioned second width of the film can easily change when the film is processed. Therefore, in the above-described configuration, the difference between the first change rate and the second change rate can be calculated at a location where the first width and the second width are easy to change. Furthermore, in the above structure, when the difference between the first change rate and the second change rate exceeds the allowable range, it can be inferred whether the difference exceeds the allowable range B and is caused by the i-th process or the i-th process. The state of the previous membrane has changed. In the above-mentioned configuration, since the reason why the business trip exceeds the allowable range can be easily specified in this manner, it is possible to avoid mistakes before they occur.

In the aforementioned manufacturing method, the aforementioned N processes may include the i-1th process and the i-th process (i is an integer equal to or greater than 2), and the aforementioned upstream site may be located at a position in the i-1th process, Furthermore, the aforementioned downstream portion is between the position of the aforementioned i-1th process and the aforementioned position of the i-th process; the aforementioned upstream portion and the aforementioned downstream portion can also be located respectively between the position of the aforementioned i-1th process and the aforementioned i-th process. i processed between positions; alternatively, the upstream position may be a position before the i-1th process, and the downstream position may be a position during the i-1th process.

In the manufacturing apparatus, the N processing units may include an i-1th processing unit and an i-th processing unit (i is an integer of 2 or more), and the upstream position acquisition device may be disposed at the i-th processing unit. The position of one processing unit, and the aforementioned downstream side position acquisition device is arranged between the aforementioned i-1th processing unit and the aforementioned i-th processing unit; the aforementioned upstream side position acquisition device and the aforementioned downstream side position acquisition unit may also be The devices are respectively arranged between the i-1th processing unit and the i-th processing unit; alternatively, the upstream side position acquisition device may be arranged before the i-1th processing unit, and, The downstream position acquisition device is arranged at the position of the i-1th processing unit.

In the above structure, the difference between the first change rate and the second change rate when the film is treated, or the first change rate and the second change rate between the end of one treatment and the next treatment for the film can be calculated. difference.

In the above-mentioned manufacturing method, during the above-mentioned transportation, an image of the first end portion and the second end portion in front of the film may be acquired by an imaging unit.

In the manufacturing apparatus, at least one of the plurality of position acquisition devices may have an imaging unit that photographs at least the first end portion and the second end portion of the film.

At this time, the position of the first end and the second end can be calculated using the image acquired through the imaging unit.

In the aforementioned manufacturing method, the positions of the first end portion and the second end portion may be obtained based on the brightness of at least one of reflected light and transmitted light from the film during the transportation, wherein the positions of the first end portion and the second end portion are obtained from the The reflected light and the transmitted light of the film are caused by the light incident on the film.

In the manufacturing apparatus, at least one of the plurality of position acquisition devices may have a light detection unit that detects at least one of reflected light and transmitted light from the film, wherein the light from the film The reflected light and the transmitted light are caused by the light incident on the film.

In the manufacturing apparatus, at least one position acquisition device among the plurality of position acquisition devices may have a light irradiation unit that irradiates light to the film. For example, when the difference in brightness of the light between the film and the surrounding environment is small when detecting the transmitted light from the film, the brightness of the surrounding environment can be increased by the light from the light irradiation part. As a result, the positions of the first end and the second end of the film can be easily detected.

In the aforementioned manufacturing method, the film may be conveyed by a conveyor roll, and the film on the conveyor roll may be irradiated with light, and the reflection of the film and the conveyor roll may be caused by the irradiated light. The difference in brightness of light is used to obtain the positions of the first end and the second end.

In the manufacturing apparatus, the conveying mechanism may have a conveying roller, the light irradiation part irradiates light to the film on the conveying roller, and at least one position acquiring device among the plurality of position acquiring devices may be based on the reason. The light irradiated from the light irradiation part to the film on the conveyor roller generates a brightness difference between the reflected light of the film and the conveyor roller, and the positions of the first end and the second end of the film are obtained.

At this time, it is easy to specify the positions of the first end and the second end of the film based on the difference in brightness between the reflected light from the film and the reflected light from the transport roller. As a result, the difference between the first change rate and the second change rate can be calculated more accurately. When the reflected light from the film is regular reflection and has sufficient brightness, the measurement is not limited to the transport roller.

In the aforementioned manufacturing method, the aforementioned transmitted light may also be the transmitted light from the aforementioned film, wherein the transmitted light from the aforementioned film is caused by the light incident on the aforementioned film through a polarizing filter. By. Alternatively, in the aforementioned manufacturing method, the positions of the first end and the second end of the film may also be obtained based on the brightness of the light obtained by passing the transmitted light through the polarizing film.

In one embodiment of the manufacturing apparatus, a polarizing filter may be provided between the light irradiation part and the film. Alternatively, an embodiment of the manufacturing apparatus may include a polarizing filter between the light detection unit and the film.

For example, when the film has linear polarization characteristics, the position of the first end and the second end of the film can be easily obtained by disposing the polarizing filter in a crossed nicol state with the film.

In the aforementioned manufacturing method, the aforementioned N treatments may also include at least one of swelling treatment, dyeing treatment, stretching treatment and drying treatment.

In the manufacturing apparatus, the N processing sections may include at least any one of a swelling processing section, a dyeing processing section, a cross-linking processing section, a stretching processing section and a drying processing section.

An example of the aforementioned optical film is a polarizing filter.

According to the present invention, it is possible to provide an optical film manufacturing method and an optical film manufacturing device that can be implemented in stable steps, have stable quality, and can also reduce material costs.

2: Membrane

2a: first end

2b: second end

4: Polarizing film (optical film)

6: Raw material roll

10:Manufacturing device

11, 11 ₁ to 11 ₆ : Roller

12, 12 ₁ to 12 ₁₂ : Guide roller

13 ₁ : Swelling treatment department

13 ₂ :Dyeing processing department

13 ₃ : Cross-linking processing department

13 ₄ : Cleaning processing department

13 ₅ : Drying processing department

20, 20 ₁ to 20 ₁₂ : Acquisition points (plural parts)

30: Location acquisition device

30 _UP : Upstream side position acquisition device

30 _DOWN : Downstream side position acquisition device

31, 31A, 31B: end detector

32:Light irradiation part

33, 36: Light detection department (camera department)

34, 35: Shell

34a, 35a: window

37:Polarizing filter

40: Calculation Department

B, Bx, By: reference position

R:Conveying roller

W1a, W2a: first width

W1b, W2b: second width

Figure 1 is a schematic diagram illustrating a method of manufacturing an optical film according to an embodiment.

Figure 2 is a diagram for explaining the change in film width in the manufacturing method of the optical film.

Fig. 3 is a diagram for explaining the position acquisition device and the calculation unit.

FIG. 4 is a diagram illustrating an example of a width detector included in the position acquisition device.

FIG. 5 is a diagram for explaining another example of the width detector included in the position acquisition device.

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or equivalent parts are assigned the same symbols, and repeated descriptions are omitted. Dimensional ratios in the drawings may not be consistent with those illustrated.

Figure 1 is a schematic diagram illustrating an embodiment of the present invention. Hereinafter, the case of manufacturing a polarizing film as an optical film will be described as an example.

In this embodiment, the polarizing film (optical film) 4 is manufactured by sequentially performing N processes (N is an integer equal to or greater than 1) on the film 2 being conveyed while conveying the long film 2 . The N processes are processes that impart at least linear polarization characteristics as optical properties to the film 2 . Although the upper limit of N is not particularly limited, N is usually an integer of 30 or less, and may be an integer of 25 or less, an integer of 20 or less, or an integer of 10 or less.

When the film 2 is given linear polarization characteristics, the film 2 functions as the polarizing film 4 . The linear polarization characteristics are substantially imparted before all N processes are completed. Therefore, in the manufacturing method of the polarizing film 4 using the film 2, the film 2 functions as the polarizing film 4 during the manufacturing process. However, for the convenience of explanation, unless otherwise stated, the film 2 after all N processes have been completed will be called the polarizing film 4, and the film before the N processes have been completed will be called the film 2. When the polarizing film 4 is manufactured, the film 2 is usually subjected to swelling treatment, dyeing treatment, cross-linking treatment, stretching treatment and drying treatment. The stretching treatment can be performed on the film 2 in any one treatment (for example, cross-linking treatment), or it can be performed on the film 2 simultaneously while performing a plurality of treatments.

Film 2 is a polyvinyl alcohol-based resin film. An example of the length of the membrane 2 in the longitudinal direction is from 1,000 m to 30,000 m, preferably from 1,000 m to 20,000 m. An example of the length of the film 2 in the width direction (the direction orthogonal to the longitudinal direction) is 1300 mm to 5000 mm. An example of the thickness of the film 2 before being subjected to N treatments is 10 μm to 100 μm. The film 2 can be produced by a known method such as a melt extrusion method or a solvent casting method. The film 2 may also be a purchased film or a film that has been stretched or laminated in advance. In the case shown in FIG. 1 , the film 2 is prepared as the raw material roll 6 , and N processes are performed on the film 2 extracted from the raw material roll 6 to obtain the polarizing film 4 . When the film 2 is produced by the aforementioned method (melt extrusion method, solvent casting method, etc.), the film 2 produced by the aforementioned method (melt extrusion method, solvent casting method, etc.) may be continuously transported, for example. During this transfer, the aforementioned N processes are performed.

The manufacturing device 10 of the polarizing film 4 is equipped with: a plurality of nip rolls 11; a plurality of guide rolls 12; a swelling treatment section 13 ₁ ; a dyeing treatment section 13 ₂ ; a cross-linking treatment section 13 ₃ ; and a cleaning process. Part 13 ₄ ; and drying treatment part 13 ₅ .

The plurality of nip rollers 11 and the plurality of guide rollers 12 are conveyance rollers included in the conveyance mechanism of the film 2 and used to convey the film 2 . By appropriately arranging the plurality of rollers 11 and the plurality of guide rollers 12, the conveyance path of the film 2 is formed.

The roll 11 has a function of clamping and pressing the film 2 to impart the rotational force of the roll 11 to the film 2 . The roll 11 also has the function of changing the conveyance direction of the film 2 . In the conveyance direction of the film 2, for example, by providing a circumferential speed difference between two adjacent rolls 11, the film 2 conveyed between the two adjacent rolls 11 is subjected to a stretching process (for example, a one-axis stretching process). FIG. 1 illustrates a case where the manufacturing device 10 has six rolls 11 . When describing the six rolls 11 separately, as shown in FIG. 1 , the six rolls 11 are called rolls 11 ₁ to 11 ₆ .

The guide roller 12 has the function of supporting the film 2 and changing the conveyance direction of the film 2 . FIG. 1 illustrates a case where the manufacturing apparatus 10 has 12 guide rollers 12 . When the 12 guide rollers 12 are explained separately, as shown in FIG. 1 , the 12 guide rollers 12 are referred to as guide rollers 12 ₁ to 12 ₁₂ .

The swelling treatment part 13 ₁ is a part that performs swelling treatment on the film 2 . The swelling treatment section 13 ₁ has a treatment tank that stores a treatment liquid for swelling treatment. The membrane 2 is immersed in the treatment liquid included in the swelling treatment unit 13 ₁ to perform swelling treatment on the membrane 2 . In this embodiment, the film conveyance path for immersing the film 2 in the treatment liquid is formed by the nip roller 11 ₁ and the guide rollers 12 ₁ to 12 ₃ . In this structure, the nip roller 11 ₁ and the guide roller 12 ₃ are disposed before and after the swelling treatment of the film 2 by the swelling treatment unit 13 ₁ (in other words, before and after the swelling treatment unit 13 ₁ ).

The aforementioned swelling treatment is performed for the purpose of removing foreign matter on the surface of the film 2, removing the plasticizer in the film 2, imparting easy dyeing in subsequent steps, and plasticizing the film 2. The conditions for the swelling treatment can be determined within a range that can achieve the above purposes and within a range that does not cause extreme dissolution, devitrification, or other defects of the membrane 2 . In the swelling treatment part 13 ₁ , the swelling treatment is performed by immersing the membrane 2 in a treatment liquid with a temperature of 10 to 50°C, preferably 20 to 50°C. The swelling treatment time is about 5 to 300 seconds, preferably about 20 to 240 seconds. An example of the treatment liquid in the swelling treatment part ₁₃₁ is water. Therefore, the swelling treatment can also serve as the water washing treatment of the membrane 2 .

The dyeing processing part 13 ₂ is a part that performs dyeing processing on the membrane 2 . The dyeing processing section 13 ₂ has a processing tank that stores a processing liquid for dyeing processing. The membrane 2 is dyed by immersing the membrane in the processing liquid included in the dyeing processing section 13 ₂ . In this embodiment, the film conveyance path for immersing the film 2 in the treatment liquid is formed by the nip roller 11 ₂ and the guide rollers 12 ₄ to 12 ₆ . In this configuration, the nip roller 11 ₂ and the guide roller 12 ₆ are disposed before and after the dyeing process is performed on the film 2 by the dyeing processing unit 13 ₂ (in other words, before and after the dyeing processing unit 13 ₂ ).

The treatment liquid included in the dyeing treatment section 13 ₂ in this embodiment is an aqueous solution of a dichroic dye, and in the dyeing treatment, the film 2 is dyed with the dichroic dye. The dyeing process using a dichroic dye is usually performed for the purpose of adsorbing the dichroic dye to the film 2 or the like. The treatment conditions are determined in accordance with the desired optical properties within a range that can achieve this purpose and within a range that does not cause extreme dissolution, devitrification, or other defects of the film 2 . Examples of dichroic pigments used for dyeing are iodine and dichroic dyes.

When iodine is used as the dichroic dye, it is, for example, at a temperature of 10 to 50°C, preferably 15 to 40°C, and contains 0.003 to 0.2 parts by weight of iodine and 0.1 to 10 parts by weight relative to 100 parts by weight of water. The membrane 2 is immersed in an aqueous solution of potassium iodide for 10 to 600 seconds, preferably 30 to 300 seconds, thereby performing dyeing treatment. Other iodides, such as zinc iodide, can also be used instead of potassium iodide. Other iodides can also be used together with potassium iodide. Furthermore, compounds other than iodide, such as boric acid, zinc chloride, cobalt chloride, etc., may also coexist. If the treatment liquid contains 0.003 parts by weight or more of iodine based on 100 parts by weight of water, it can be regarded as a treatment liquid for dyeing.

When a water-soluble dichroic dye is used as the dichroic pigment, it is, for example, at a temperature of 20 to 80°C, preferably 30 to 60°C, and contains 0.001 to 0.1 parts by weight of dichroic dye relative to 100 parts by weight of water. The membrane 2 is immersed in the aqueous solution of the color dye for 10 to 600 seconds, preferably 20 to 300 seconds, thereby performing dyeing treatment. The aqueous solution of the dichroic dye used may also contain dyeing auxiliaries, etc., and may also contain inorganic salts such as sodium sulfate, surfactants, etc. Only one type of dichroic dye may be used, or two or more types of dichroic dyes may be used in combination depending on the desired hue.

The cross-linking treatment part 13 ₃ is a part that performs cross-linking treatment on the film 2 . The cross-linking processing section 13 ₃ has a processing tank that stores a processing liquid for cross-linking processing. The membrane 2 is cross-linked by immersing the membrane in the treatment liquid included in the cross-linking section 13 ₃ . In this embodiment, the film conveyance path for immersing the film 2 in the treatment liquid is formed by the nip roller 11 ₃ and the guide rollers 12 ₇ to 12 ₉ . In this structure, the nip roller 11 ₃ and the guide roller 12 ₉ are disposed before and after the cross-linking process of the film 2 by the cross-linking process section 13 ₃ (in other words, before and after the cross-linking process section 13 ₃ ).

The cross-linking treatment is a treatment performed for the purpose of water resistance by cross-linking, hue adjustment (preventing the film 2 from being bluish, etc.), and the like.

The treatment liquid used in the cross-linking treatment part 13 ₃ is, for example, an aqueous solution containing, for example, about 1 to 10 parts by weight of boric acid relative to 100 parts by weight of water. When the dichroic dye used in the dyeing process is iodine, the treatment liquid used in the cross-linking treatment part 13 ₃ preferably contains iodide in addition to boric acid, and its content is, for example, based on 100 parts by weight of water. 1 to 30 weight portions. Examples of iodide include potassium iodide, zinc iodide, and the like. Compounds other than iodide, such as zinc chloride, cobalt chloride, zirconium chloride, sodium thiosulfate, potassium sulfite, sodium sulfate, etc., may also coexist.

During the cross-linking treatment in the cross-linking treatment section 13 ₃ , the concentrations of boric acid and iodide and the temperature of the treatment liquid can be appropriately changed depending on the purpose.

For example, when the purpose of the cross-linking treatment is to achieve water resistance by cross-linking, and the polyvinyl alcohol-based resin film is sequentially subjected to swelling treatment, dyeing treatment and cross-linking treatment, the cross-linking agent-containing liquid of the treatment liquid, The system is, for example, an aqueous solution with a concentration of boric acid/iodide/water=3 to 10/1 to 20/100 in terms of weight ratio. If necessary, other cross-linking agents such as glyoxal or glutaraldehyde can be used instead of boric acid, or boric acid and other cross-linking agents can be used in combination. The temperature of the treatment liquid when immersing membrane 2 is usually about 50°C to 70°C, preferably 53°C to 65°C. The immersion time of membrane 2 is usually about 10 to 600 seconds, preferably 20 to 300 seconds. Better is 20 to 200 seconds. When the membrane 2 that has been pre-stretched before the swelling treatment is sequentially subjected to dyeing treatment and cross-linking treatment, the temperature of the treatment liquid is usually 50 to 85°C, preferably 55 to 80°C.

The purpose of cross-linking treatment is to adjust the hue. For example, when using iodine as a dichroic pigment, a cross-linking agent containing solution with a concentration by weight of boric acid/iodide/water = 1 to 5/3 to 30/100 can be used. as a treatment fluid. The temperature of the treatment liquid when the membrane 2 is immersed is usually about 10 to 45°C, and the immersion time of the membrane 2 is usually about 1 to 300 seconds, preferably 2 to 100 seconds.

The cleaning processing part 13 ₄ is a part that performs cleaning processing on the cross-linked membrane 2 . The cleaning processing section 13 ₄ has a processing tank that stores a processing liquid used for cleaning processing. By immersing the membrane 2 in the treatment liquid contained in the cleaning treatment unit 13 ₄ , the membrane 2 is cleaned. In this embodiment, the film conveyance path for immersing the film 2 in the treatment liquid is formed by the nip roller 11 ₄ and the guide rollers 12 ₁₀ to 12 ₁₂ . In this configuration, the nip rollers 11 ₄ and the guide rollers 12 ₁₂ are arranged before and after the cleaning process of the membrane 2 is performed by the cleaning process unit 13 ₄ (in other words, before and after the cleaning process unit 13 ₄ ). Examples of the treatment liquid in the cleaning process include water, an aqueous solution containing potassium iodide, and an aqueous solution containing boric acid. The temperature of the treatment liquid is usually about 2°C to 40°C, and the treatment time is usually about 2 seconds to 120 seconds.

The cleaning process in the cleaning processing section 13 ₄ can also be carried out by spraying the processing liquid in a shower method, or a method of combining immersion and spraying to clean the membrane 2 .

The drying processing part 13 ₅ is a part that performs drying processing on the film 2 . In this embodiment, the drying processing part 13 ₅ is a drying device. The membrane 2 that has been cleaned by the cleaning processing unit 13 ₄ is loaded into the drying processing unit 13 ₅ , and the membrane 2 is dried while the membrane 2 passes through the drying processing unit 13 ₅ . In this embodiment, the film conveyance path for immersing the film 2 in the treatment liquid is formed by the rollers 11 ₅ and 11 ₆ . In the drying processing section ₁₃₅ , the guide roller 12 can also be appropriately arranged to support and transport the film 2. Drying by the drying processing part 13 ₅ is performed in the drying processing part 13 ₅ maintained at a temperature of about 40° C. to 100° C. for about 30 seconds to about 600 seconds. In Fig. 1 , the drying processing section 13 ₅ is schematically shown. The drying treatment part 13 ₅ is not particularly limited as long as it can dry the moisture adhering to the film 2 , and may be a well-known one commonly used in the production of polarizing films.

In the manufacturing apparatus 10, a stretching process is performed in which the film 2 is uniaxially stretched using the difference in circumferential speed of at least two of the plurality of rolls 11 (the upstream roll 11 and the downstream roll 11). handle. At this time, the two rolls 11 that contribute to the one-axis stretching process function as a stretching processing section.

For example, a stretching process may be performed in which a one-axis stretching process is performed using the difference in circumferential speed between the roll 11 _{3 disposed before the cross-linking processing section 13 3 and} the roll 11 ₄ disposed after the cross-linking processing section 13 ₃ . At this time, the stretching process is performed simultaneously with the cross-linking process, so the cross-linking processing section 13 ₃ also functions as a stretching processing section. Extension treatment is also effective in inhibiting the occurrence of wrinkles.

It is also possible to mainly use two rolls 11 arranged before and after one processing section (for example, the aforementioned cross-linking processing section 13 ₃ ) to perform the stretching process, and on the other hand, use other rolls 11 to gradually perform the stretching process.

The manufacturing apparatus 10 may additionally have a stretching processing unit for performing stretching processing. At this time, the stretching processing part is, for example, disposed at the rear stage of the cross-linking processing part 13 ₃ (for example, between the cross-linking processing part 13 ₃ and the cleaning processing part 13 ₄ ).

The manufacturing apparatus 10 may have at least one of a plurality of swelling processing parts 13 ₁ , dyeing processing parts 13 ₂ , crosslinking processing parts 13 ₃ , cleaning processing parts 13 ₄ and drying processing parts 13 ₅ . For example, the manufacturing apparatus 10 may be provided with a plurality of cross-linking treatment units 13 ₃ . The same applies to the case where the manufacturing apparatus 10 is provided with a stretching processing unit. The manufacturing apparatus 10 may also be provided with a plurality of stretching processing units, for example.

When the polarizing film 4 is manufactured using the above-mentioned manufacturing device 10, first, the film 2 is pulled out from the raw material roll 6, and the film 2 is transported in the longitudinal direction along the conveyance path formed by the plurality of rolls 11 and the plurality of guide rollers 12. Transport. For example, the conveying speed may be 1m/min to 60m/min, or may be 1.5m/min to 50m/min. In the conveyance path of the film 2, a swelling treatment part 13 ₁ , a dyeing treatment part 13 ₂ , a crosslinking treatment part 13 ₃ , a cleaning treatment part 13 ₄ and a drying treatment part 13 ₅ are provided from the raw material roll 6 side. Furthermore, as mentioned above, at least two rolls 11 also function as stretching processing parts. Therefore, the conveyed film 2 is subjected to swelling processing, dyeing processing, cross-linking processing, cleaning processing, and drying processing, and is also subjected to stretching processing. Thereby, linear polarization characteristics (optical characteristics) are imparted to the film 2, and the polarizing film 4 is obtained.

The polarizing film 4 obtained through the drying treatment section 13 ₅ is used, for example, for manufacturing a polarizing plate including the polarizing film 4 . For example, the aforementioned polarizing plate can be manufactured by performing a laminating step in which the protective film is bonded to one or both sides of the polarizing film 4 . The polarizing film 4 obtained through the drying treatment section ₁₃₅ can be continuously conveyed to manufacture the aforementioned polarizing plate, or can be temporarily rolled into a roll shape.

As shown in FIG. 2 , in the process of manufacturing the polarizing film 4 by performing N processes while conveying the film 2 , the length of the film 2 in the width direction changes. At this time, the change rate of the first width between the reference position B of the film 2 in the width direction of the film 2 and the first end 2a of the film 2 (hereinafter referred to as the "first reduction rate"), and The change rate of the second width between the aforementioned reference position and the second end portion 2b of the film 2 (hereinafter referred to as the “second narrowing rate”) may be different.

Herein, the one located on the upstream side among any two locations in the transportation of the film 2 is called the upstream location, and the other location located on the downstream side than the upstream location is called the downstream location. The reference position B of the film 2 is set so that the straight line connecting the reference position Bx located in the upstream part and the reference position By located in the downstream part becomes a straight line parallel to the conveyance direction of the film 2 .

An example of the reference position Bx is the center position of the film 2 in the upstream position in the width direction.

Let the above-mentioned first width (the distance between the reference position B and the first end 2a) in the upstream part be W1a, the above-mentioned second width (the distance between the reference position B and the second end 2b) be W1b, before downstream position Let the first width be W2a and the second width be W2b. When the first narrowing rate (%) of the first width and the second narrowing rate (%) of the second width between the upstream part and the downstream part are respectively set to α (%) and β (%), the first When the difference (%) between the narrowing ratio and the second narrowing ratio is γ (%), in this embodiment, α, β, and γ are defined as follows.

α=[(W1a-W2a)/W1a]×100...(1)

β=[(W1b-W2b)/W1b]×100...(2)

γ=|α-β|...(3)

In an embodiment of the present invention, there is further a monitoring step of monitoring the difference γ between the first amplitude reduction rate (first change rate) α and the second amplitude reduction rate (second change rate) β. In the monitoring step, as shown in FIG. 1 , the positions of the first end 2 a and the second end 2 b of the film 2 are continuously acquired at a plurality of acquisition points 20 (a plurality of locations) in the film 2 being transported. (Hereinafter also referred to as "end positions"). In Fig. 1, a plurality of acquisition points 20 are indicated by arrows. When the plurality of acquisition points 20 are described separately, the plurality of acquisition points 20 are referred to as acquisition points 20 ₁ to 20 ₁₂ .

The acquisition point 20 may be a point to acquire the positions of both ends of the film 2 that is wound up on the roller 11 or the guide roller 12, or it may be a point to acquire both ends of the film 2 that is not wound up on the roller 11 or the guide roller 12. location point. The acquisition point 20 shown in Figure 1 is an example. For example, the acquisition point 20 ₁ may also be a point to acquire the positions of both ends of the film 2 fed from the roller 11 ₁ , and the acquisition point 20 ₄ may also be a point to acquire the wound position. Points at both ends of the film 2 on the guide roller 12 ₆ (film 2 on the guide roller 12 ₆ ).

The acquisition points 20 ₁ to 20 ₃ before the dyeing process is performed on the film 2 are preferably the points at both ends of the film 2 that is wound around the nip roller 11 or the guide roller 12 . On the other hand, after the acquisition point ₂₀₄ , the relationship between the nip roller 11 or the guide roller 12 and the film 2 is generally not limited.

The acquisition point 20 may be arranged, for example, before and after one of the N processes is performed on the membrane 2 . For example, the acquisition point 20 ₁ is a point that acquires the position of both ends of the film 2 in a state of being wound around the roll 11 ₁ or immediately after being sent out from the roll 11 ₁ in Figure 1, and is an acquisition point before the swelling process is performed. The acquisition point 20 ₂ is a point at which the positions of both ends of the film 2 are acquired on the guide roller 12 ₃ or immediately after being sent out from the guide roller 12 ₃ .

Therefore, the acquisition points 20 ₁ and 20 ₂ are points for acquiring the positions of both ends of the film 2 before and after the swelling process is performed on the film 2 . In this way, the acquisition points before and after a treatment (before and after the membrane is immersed in the treatment liquid of a certain treatment section) are also the acquisition points before and after the treatment section where the treatment is carried out.

Another example of the acquisition point 20 is the acquisition points 20 ₃ and 20 ₄ , the acquisition points 20 ₅ and 20 ₇ , the acquisition points 20 ₈ and 20 ₁₀ , and the acquisition points 20 ₁₁ and 20 ₁₂ . The acquisition points 20 ₃ and 20 ₄ , the acquisition points 20 ₅ and 20 ₇ and the acquisition points 20 ₈ and 20 ₁₀ are for obtaining the positions of both ends of the membrane 2 before and after the swelling treatment, dyeing treatment, cross-linking treatment and cleaning treatment. point. The acquisition points 20 ₁₁ and 20 ₁₂ are points for acquiring the positions of both ends of the film 2 before and after the drying process.

The acquisition point 20 may also be a point at which the positions of the first end 2 a and the second end 2 b of the membrane 2 are acquired during a step in which processing is performed on the membrane 2 . Examples of such acquisition points 20 are acquisition points 20 ₆ and 20 ₉ . The acquisition point 20 ₆ is an acquisition point during the conveyance of the film 2 between the guide roller 12 ₇ and the guide roller 12 ₈ . Similarly, the acquisition point 20 ₉ is an acquisition point during the conveyance of the film 2 between the guide roller 12 ₁₀ and the guide roller 12 ₁₁ . At the acquisition points 20 ₆ and 20 ₉ , the positions of both ends of the membrane 2 in the treatment liquid are acquired.

In the monitoring step, the acquisition result (hereinafter referred to as " The first narrowing ratio α is calculated by obtaining the position of the first end portion 2a and the second end portion 2b of the film 2 in the downstream portion (hereinafter referred to as the "second acquisition result") and the first acquisition result" The difference γ from the second shrinkage rate β. The first acquisition result and the second acquisition result may also be, for example, results obtained when the aforementioned upstream part and the downstream part are at the same time point (that is, at the same time) (that is, the aforementioned two parts may also be measured at the same time point ( Upstream parts and downstream parts)). "The same point in time (that is, at the same time)" can also be used without departing from the meaning of the present invention. There are some deviations within the range. The time difference between the time of measurement at the aforementioned upstream site and the time of measurement at the aforementioned downstream site is not particularly limited, but may be within about one minute, may be within 30 seconds, may be within 20 seconds, or may be within 10 seconds Within. The monitoring step is preferably implemented in an automated manner.

For example, the upstream part and the downstream part are the upstream part before one of the N processes (hereinafter referred to as "predetermined processing"), and the downstream part is after the aforementioned predetermined processing. For example, when the aforementioned predetermined process is a dyeing process, the upstream site is before the dyeing process and the downstream site is after the dyeing process. The so-called "before scheduled processing" and "after scheduled processing" also include the case where other processing is performed between the upstream part and the downstream part and the aforementioned "scheduled processing".

When any two adjacent processes among the N processes are called the i-1th process and the i-th process (i is an integer greater than 2), and the corresponding processing unit is called the i-1th processing unit In the case of the i-th processing section, the upstream part and the downstream part may be any one of the following arrangement examples 1 to 3.

In this specification, the upper limit of i is not particularly limited, but i is usually an integer of 30 or less, and may be an integer of 25 or less, 20 or less, or 10 or less.

[Configuration example 1]

The upstream part is located at the position of the i-1th processing (the position of the i-1th processing part), and the downstream part is at the position of the i-1th processing (i-1th processing part) and the i-th processing part. between the positions of processing (i-th processing unit). For example, when the i-1th process is a cross-linking process, among the plurality of acquisition points 20 shown in FIG. 1, examples of the upstream part and the downstream part are the acquisition point 20 ₆ and the acquisition point 20 ₇ .

[Configuration example 2]

The upstream portion and the downstream portion are respectively between the position of the i-1th process (i-1th processing unit) and the i-th process (i-th processing unit). For example, when the i-1th process is a cross-linking process, among the plurality of acquisition points 20 shown in Fig. 1, examples of the upstream part and the downstream part are the acquisition point ₂₀₇ and the acquisition point ₂₀₈ .

[Configuration example 3]

The upstream part is the position before the i-1th process (i-1th processing part), and the downstream part is the position during the i-1th process (the position of the i-1th processing part). For example, when the i-1th process is a cross-linking process, among the plurality of acquisition points 20 shown in FIG. 1, examples of the upstream part and the downstream part are the acquisition point 20 ₅ and the acquisition point 20 ₆ .

When i is an integer greater than or equal to 2, the process next to the i-th process is called the i+1th process, and the corresponding processing unit is called the i+1th processing unit, the upstream part and the downstream part For example, the following configuration example 4 can also be used.

[Configuration example 4]

The upstream part is between the position of the i-1th process (i-1th processing unit) and the i-th process (i-th processing part), and the downstream part is between the i-th process (i-th processing part) between the position of the processing unit) and the position of the i+1th processing (i+1th processing unit). For example, when the i-1th process is a cross-linking process, among the plurality of acquisition points 20 shown in FIG. 1, examples of the upstream part and the downstream part are the acquisition point 20 ₇ and the acquisition point 20 ₁₀ .

For example, a combination of two non-adjacent acquisition points 20 may be used as the combination of the upstream part and the downstream part, such that the upstream part is the acquisition point 20 ₁ and the downstream part is the acquisition point 20 ₈ .

When the manufacturing apparatus 10 has at least one of a plurality of swelling processing parts 13 ₁ , dyeing processing parts 13 ₂ , cross-linking processing parts 13 ₃ , cleaning processing parts 13 ₄ , and drying processing parts 13 ₅ , the upstream part and the downstream part They may be parts that are treated for the same purpose, or they may be parts that are treated for different purposes. For example, when the manufacturing apparatus 10 has two or more swelling processing parts 13 ₁ and the two swelling processing parts 13 ₁ are called swelling processing parts 13 ₁ -a and 13 ₁ -b, the upstream part can be called the swelling processing part 13 ₁ -a (or before or after it), and the downstream part is the swelling treatment part 13 ₁ -b (or before or after it), or the upstream part is the swelling treatment part 13 ₁ -a or the position of the swelling treatment part 13 ₁ -b (or before or after it), and the downstream part is the position of the dyeing treatment part 13 ₂ (or before or after it). The same is true when there are a plurality of stretching processing parts.

The difference γ between the first narrowing ratio α and the second narrowing ratio β can also be calculated by a plurality of combinations of upstream parts and downstream parts selected from a plurality of acquisition points 20 . For example, the difference γ between the first reduction ratio α and the second reduction ratio β may be calculated based on the acquisition result at the acquisition point 20 ₁ and the acquisition result at the acquisition point 20 ₂ , and based on the acquisition result at the acquisition point 20 ₅ The difference γ is calculated from the acquisition result at acquisition point ₂₀₇ . Among the plurality of combinations of the upstream part and the downstream part, the upstream part and the downstream part may be a common combination. For example, the difference γ can be calculated based on the acquisition results of the acquisition point 20 ₁ and the acquisition point 20 ₂ , and the difference γ can be calculated based on the acquisition results of the acquisition point 20 ₁ and the acquisition point 20 ₄ . Similarly, the difference γ may be calculated based on the acquisition result of the acquisition point 20 ₅ and the acquisition point 20 ₇ , and the difference γ may be calculated based on the acquisition result of the acquisition point 20 ₆ and the acquisition point 20 ₇ .

In order to calculate the difference γ, as shown in FIG. 3 , the optical film manufacturing device 10 includes a plurality of position acquisition devices 30 and a calculation unit 40 .

Each position acquisition device 30 is a device that continuously acquires the positions of the first end portion 2a and the second end portion 2b of the film 2. The plurality of position acquisition devices 30 are arranged on a one-to-one basis at the plurality of acquisition points 20 . That is, one position acquisition device 30 is arranged at one acquisition point 20 . In FIG. 3 , two position acquiring devices 30 selected for calculating the difference γ among the plurality of position acquiring devices 30 are schematically shown (that is, the upstream side position acquiring device 30 arranged at the upstream position). _UP , the downstream side position acquisition device 30 _DOWN ), and the calculation unit 40 arranged at the downstream location.

The position acquisition device 30 has two end detectors 31 . One of the two end detectors 31 is a detector that detects the first end 2a, and the other is a detector that detects the second end 2b. The position acquisition device 30 is configured to detect the first end portion 2a of the film 2 and the position of the film 2 based on the state of the film 2 at the acquisition point 20. Second end 2b. Therefore, the structure of the position acquisition device 30 may also be different for each acquisition point 20 . However, the configurations of the two end detectors 31 (the two end detectors 31 arranged at one acquisition point 20) included in one position acquisition device 30 are the same.

FIG. 4 is a schematic diagram for explaining the schematic structure of the end detector 31A which is an example of the end detector 31. As shown in FIG. The end detector 31A is a detector used when acquiring the positions of the first end 2a and the second end 2b of the film 2 on the conveyance roller R. The conveyance roller R is the roll roller 11 or the guide roller 12 shown in FIG. 1 .

Two end detectors 31A are arranged on the film 2 to detect the first end 2a and the second end 2b respectively. However, as described above, since the end detector 31A has the same configuration, a case where the end detector 31A detects the first end 2 a will be described.

The end detector 31A has a light irradiation part 32 and a light detection part 33. In FIG. 4, the state where the film 2 is arrange|positioned on the conveyance roller R is illustrated.

The light irradiation part 32 irradiates the film 2 with light. The light irradiation part 32 is configured to irradiate light toward the outer side than the first end part 2 a of the film 2 . Therefore, as shown in FIG. 4 , when the film 2 is placed on the conveyance roller R, the light from the light irradiation part 32 also irradiates the portion of the conveyance roller R that does not overlap the film 2 . The light irradiation part 32 may be a linear light source extending in the width direction of the film 2 . The light irradiation part 32 may include, for example, an LED (Light Emitting Diode).

The light irradiation part 32 may also be disposed inside the housing 34 . The casing 34 has a window 34a for irradiating the film 2 with the light output from the light irradiation part 32. The window portion 34a just needs to be made of a material that allows the light output from the light irradiation portion 32 to pass through. For example, examples of materials for the window portion 34a include polycarbonate resin, acrylic resin, vinyl chloride resin, polypropylene resin, and polyethylene terephthalate. Resin and glass.

The light detection unit 33 detects the brightness of light (reflected light) reflected by the film 2 from the light irradiation unit 32 to the film 2 . The light detection unit 33 may be an imaging unit such as a camera (for example, a CCD (Charge-Coupled Device) camera) that photographs at least the first end portion 2 a of the film 2 . As shown in FIG. 4 , when the film 2 is placed on the conveyance roller R, the light detection unit 33 also detects the brightness of the light reflected by the conveyance roller R among the light irradiated from the light irradiation unit 32 to the film 2 .

The light detection unit 33 is arranged inside the housing 35 . The housing 35 has a window part 35a for detecting the reflected light by the light detection part 33. The window portion 35a may be made of a material that allows the reflected light to pass through. Examples of materials for the window portion 35a are the same as those for the window portion 34a.

The acquisition points 20 ₁ , 20 ₂ , and 20 ₃ before the dyeing process is performed on the film 2 are generally the points at which the positions of the first end 2 a and the second end 2 b of the film 2 on the conveyance roller R are acquired. Therefore, the end detector 31A is suitable for use at the acquisition points 20 ₁ , 20 ₂ , and 20 ₃ .

FIG. 5 is a schematic diagram illustrating the schematic structure of the end detector 31B which is another example of the end detector 31 . The end detector 31B is a detector suitable for use when the film 2 has linear polarization characteristics (when an absorption axis is formed). Generally, the end detector 31B can be applied to the membrane 2 after dyeing processing is performed in the dyeing processing section ₁₃₂ .

Two end detectors 31B are arranged on the film 2 to detect the first end 2a and the second end 2b respectively. However, as described above, since the end detector 31B has the same configuration, a case where the end detector 31B detects the first end 2 a will be described.

The end detector 31B has a light detection part 36 and a polarization filter 37.

The light detection unit 36 detects the brightness of light from the surrounding environment of the film 2 that is incident on the film 2 and passes through the film 2 (hereinafter referred to as "light from the film 2"). The light detection unit 36 may be an imaging unit such as a camera (for example, a CCD camera) that photographs at least the first end portion 2 a of the film 2 .

The aforementioned "light from the surrounding environment of the film 2" includes illumination light from lighting fixtures installed in a factory that manufactures the polarizing film 4, and reflection of the illumination light to elements constituting the manufacturing device 10 (for example, the roller 11 and the guide roller). 12 and the like, at least one of the side wall and the bottom wall of the processing tank of each processing unit shown in Figure 1, the floor of the aforementioned factory, etc.). In Figure 5, the light of the surrounding environment of the film 2 is schematically shown by a white arrow.

The polarizing filter 37 is a filter having linear polarization characteristics. The polarizing filter 37 is disposed between the photodetector 36 and the film 2 so that the absorption axis of the film 2 and the absorption axis of the polarizing filter 37 enter a crossed Nicol state. The so-called crossed Nicol state mentioned above is not limited to the case where the angle formed by the absorption axis of the film 2 and the absorption axis of the polarizing filter 37 is 90 degrees. It also includes, for example, ±5 degrees and ±10 degrees with respect to 90 degrees. Degree or the meaning of error of about 15 degrees.

The photodetector 36 and the polarizing filter 37 can be arranged in the housing 35 having the window 35a in the same manner as the photodetector 33. The window portion 35a only needs to be made of a material that allows light from the film 2 to pass through.

In the case of using only the light from the surrounding environment of the film 2 , when the difference in brightness between the light from the surrounding environment detected by the light detection part 36 and the light passing through the film 2 is small, the end detector 31B may also have Auxiliary lighting unit (light irradiation unit). The structure of the auxiliary lighting unit can be the same as that of the light irradiation unit 32 . The auxiliary lighting unit may be configured to output light that is smaller than the light irradiation unit 32 or has smaller energy than the power of the light output from the light irradiation unit 32 . The auxiliary lighting unit may be disposed in the housing 34 having the window 34a, similarly to the light irradiation unit 32. The auxiliary lighting unit is arranged in at least one of the detection area (or imaging area) of the illumination light detection unit 33 and its surroundings, and causes the light from the auxiliary lighting unit to be incident on the film 2 as light from the surrounding environment.

The end detector 31B can also be used to detect the first end 2a of the film 2 on the conveyance roller R. The end detector 31B can be used at the acquisition points 20 ₅ , 20 ₈ , and 20 ₁₀ , for example. The conveyance roller R at this time is preferably a white roller so that the difference in brightness can be made clear.

The end detector 31B can also be used to detect the state of the first end 2a of the film 2 between the conveying roller R and the conveying roller R. The end detector 31B may be used, for example, to detect the first end 2a at the acquisition points 20 ₄ , 20 ₆ , 20 ₇ , 20 ₉ , 20 ₁₁ , and 20 ₁₂ . At this time, a white-based plate-shaped member or the like may be provided on the background of the detection area of the light detection unit 33 (or the background of the imaging area) to clarify the difference in brightness. When using the auxiliary illumination unit to detect the first end 2a of the film 2 between the two conveyance rollers R, the auxiliary illumination unit may be arranged on the same side as the end detector 31B relative to the film 2, or It can be arranged on the opposite side to the end detector 31B with respect to the film 2 .

When detecting the first end 2a at the acquisition points ₂₀₆ and ₂₀₉ , the end detector 31B acquires the position of the first end 2a of the membrane 2 in the processing liquid. At this time, for example, as shown in FIG. 5 , the end detector 31B may include a housing 35 having a window 35 a , and the housing 35 may be arranged so that the window 35 a is located in the processing liquid. When a portion of the window portion 35a is disposed in the treatment liquid, the outer surface of the window portion 35a can be subjected to at least one of hydrophilic treatment, concave and convex processing, and tilting processing. Thereby, air bubbles are less likely to remain on, for example, the outer surface of the window portion 35a, making it easier to accurately detect the first end portion 2a. When an auxiliary lighting unit is used to obtain the first end portion 2 a in the processing liquid, for example, the auxiliary lighting unit may also illuminate the bottom wall of the processing tank in which the film 2 is processed. At this time, the brightness of the transmitted light irradiated from the auxiliary illumination unit, reflected on the bottom wall of the processing tank, and transmitted through the film 2 is detected by the light detection unit 36 via the polarization filter 37 .

The polarization filter 37 included in the end detector 31B may be disposed on the incident side of the film 2 where light enters the film 2 , for example. For example, when the end detector 31B has an auxiliary lighting part (light irradiation part), the polarizing filter The wave device 37 is arranged between the auxiliary illumination unit and the film 2 instead of between the light detection unit 36 and the film 2 . At this time, the polarizing filter 37 may be arranged in a cross-Nicol state with the film 2 .

The calculation unit 40 shown in FIGS. 3 to 5 is connected to a plurality of position acquisition devices 30 (the position acquisition devices 30 arranged at the upstream part and the downstream part) in a wired or wireless manner, and obtains data from a plurality of positions based on The aforementioned difference γ is calculated based on the acquisition result obtained by the device 30 .

Specifically, the calculation unit 40 determines the position of the film 2 in the arrangement position of each position acquisition device 30 based on the data obtained by the end detector 31A (or the end detector 31B) of the plurality of position acquisition devices 30 respectively. The first end 2a and the second end 2b. The first end portion 2a and the second end portion 2b can be determined by changes in the brightness data belonging to the acquisition result of the position acquisition device 30.

For example, as shown in FIG. 4 , when the first end 2 a and the second end 2 b of the film 2 placed on the conveyance roller R are detected by the position acquisition device 30 including the end detector 31A At this time, the light detector 33 detects the brightness of the reflected light from the film 2 and the reflected light from the conveyance roller R. Since there is a difference between the brightness of the reflected light from the film 2 and the brightness of the reflected light from the transport roller R, the calculation unit 40 only needs to determine the location where the difference occurs as the first end portion 2 a and the second end portion of the film 2 2b is enough.

For example, as shown in FIG. 5 , when the first end 2 a and the second end 2 b are detected by the position acquisition device 30 including the end detector 31B, since the polarization filter 37 and the film 2 are in cross Nico In this state, the light from the film 2 is substantially blocked, but on the other hand, the light from outside the film 2 is detected. Therefore, in the image formed by the brightness data detected by the light detection unit 36, a difference in brightness occurs between the film 2 and the parts other than the film 2 (the film 2 side is darker and the other than the film 2 is brighter), so the calculation is The portion 40 only needs to determine that the location where the difference occurs is the first end portion 2a and the second end portion 2b of the film 2.

When specifically specifying the first end 2a and the second end 2b, the calculation unit 40 is based on, for example, the arrangement positions of the end detector 31A and the end detector 31B and the acquired brightness data (or image). The positions of the first end 2a and the second end 2b in the manufacturing device 10 (or the transport mechanism) are calculated by calculating the positions (eg, traveling positions) of the first end 2a and the second end 2b. When, for example, the end of the conveying roller R can be specifically specified from the brightness data obtained via the end detector 31A and the end detector 31B, the end of the conveying roller R and the first end of the film 2 are determined from the brightness data. The position of the first end 2a and the second end 2b in the manufacturing device 10 (or the conveying mechanism) is calculated based on the arrangement relationship between the end 2a and the second end 2b and the actual position of the end of the conveying roller R ( e.g. travel position)

The calculation unit 40 obtains the first acquisition result based on the first acquisition result obtained by the upstream position acquisition device 30 _UP disposed at the upstream position selected in advance from the plurality of acquisition points 20 and the downstream position acquisition device 30 _DOWN disposed at the downstream position. As a second acquisition result, as described above, the positions of the first end portion 2a and the second end portion 2b in each of the upstream portion and the downstream portion (for example, the traveling position) are calculated. Furthermore, the calculation unit 40 also calculates the reference position B based on the first acquisition result. The reference position B can be calculated, for example, as the center position of the membrane 2 in the upstream location. Examples of the upstream part and the downstream part are as described above.

Next, based on the aforementioned calculation results, the first width W1a and the second width W1b in the upstream location are calculated, and the first width W2a and the second width W2b in the downstream location are calculated, and according to the aforementioned formula (1) The difference γ is calculated using equation (3).

The calculation procedure of the difference γ has been broken down into a plurality of steps and explained. However, if the positions of the first end portion 2a and the second end portion 2b (for example, traveling positions) can be obtained based on the first acquisition result and the second acquisition result in the upstream part and the downstream part, then as long as the result and the formula ( 1) Calculate the difference γ using equation (3).

In the above-mentioned manufacturing method of the polarizing film 4 and the manufacturing device 10 of the polarizing film 4, the first end portion 2a and the first end portion 2a of the film 2 are acquired by position acquisition devices 30 respectively arranged at a plurality of acquisition points 20 (a plurality of locations). The position of the second end 2b. Thereby, while conveying the film 2, the first end portion 2a can be continuously obtained. and the position of the second end 2b. Furthermore, among the positions of the first end portion 2a and the second end portion 2b that are continuously acquired at the plurality of acquisition points 20, based on the position of the first end portion 2a and the second end portion 2b acquired at the same time point in the upstream portion and the downstream portion, The position of end 2b is used to calculate the difference γ. Therefore, during the transportation of the film 2, the difference γ of the film 2 can be obtained. In other words, the difference γ can be monitored while conveying the film 2 .

The difference γ is: between the upstream position and the downstream position, the width of the first end 2a side (first width) and the width of the second end 2b side (second width) of the film 2 are relative to The difference in the rate of change of reference position B. When the difference γ exceeds the allowable range (the management width of the difference γ) obtained in advance through experiments or simulations, for example, the load on the transport roller R that transports the film 2 will locally increase, and the load will increase locally. It is easy to cause equipment loss. When equipment is missing, the polarizing film 4 may become defective or the film 2 may be broken. Alternatively, when the difference γ exceeds the allowable range, the film thickness tends to deviate from the desired state in the width direction. For example, a difference in film thickness is likely to occur on both sides of the reference position B in the width direction. In this way, when the film thickness deviates from the desired state, the polarizing film 4 having uniform desired optical characteristics cannot be obtained, or parts with poor appearance quality may occur. As a result, the material used to manufacture the polarizing film 4 is wasted, resulting in an increase in material cost.

In the manufacturing method of the polarizing film (optical film) 4 and the manufacturing apparatus 10 of the polarizing film 4 mentioned above, the difference γ can be monitored in real time during the conveyance of the film 2, for example. Therefore, when the difference γ exceeds the allowable range, for example, the production of the polarizing film 4 can be quickly interrupted. When production is interrupted, the production conditions of the polarizing film 4 only need to be adjusted so that the difference γ falls within the allowable range. Examples of the aforementioned adjustments include: adjusting the angle of the conveyor roller R through a position adjustment mechanism such as EPC (Edge Position Control, edge control device), and adjusting the processing tank between the upstream part and the downstream part after calculating the difference γ. The distribution of temperature, flow rate, etc. in the width direction, and the repair and manufacturing device 10 (replacement of bearings, replacement of conveyor roller R), etc. In addition, for example, it is possible to continue manufacturing while adjusting the difference γ to an acceptable range. In this way, you can avoid the following steps This prevents the film 2 from breaking and suppresses the production of the polarizing film 4 that would become the aforementioned defective product. Therefore, the polarizing film 4 can be manufactured in a stable step. Furthermore, the polarizing film 4 with stable quality can be produced uniformly. Furthermore, the material cost of the polarizing film 4 can be further reduced. Furthermore, the polarizing film (optical film) 4 of good quality can be manufactured efficiently, and therefore the manufacturing yield of the polarizing film 4 is improved.

The allowable range of the difference γ may be set, for example, in a plurality of combinations of the upstream position (upstream side position acquisition device 30 _UP ) and the downstream position (downstream side position acquisition device 30 _DOWN ). An example of the allowable range is 1.0% or less. For example, the allowable range in at least one combination of the upstream site and the downstream site may be 1.0% or less, and the allowable range in all combinations of a plurality of upstream sites and downstream sites may be 1.0% or less.

The first width and the second width of the film 2 are easily changed by performing at least one of the N processes on the film 2 . Therefore, as mentioned above, when the upstream position is before the predetermined processing among the N processes and the downstream position is after the predetermined processing, it will be easy to monitor defects in the production of the polarizing film 4 (for example, in the width direction of the film 2 The difference γ between the film thickness difference on both sides of the reference position B, equipment failure, breakage of the film 2 in the subsequent steps, etc.).

For the same reason, in the case of the aforementioned arrangement examples 1 to 4, it is also easy to monitor the difference γ that contributes to defects in the production of the polarizing film 4 . For example, in the configuration state, it is possible to specifically specify the impact of changes in the state before or after a certain process, changes in the state caused by the process, or changes in the state during the process on the difference γ. Therefore, when the difference γ deviates from the allowable range, it is easy to adjust the manufacturing conditions.

As a result, the material cost of the polarizing film 4 can be further reduced, and the manufacturing yield of the polarizing film 4 can be further improved. In addition, the polarizing film 4 with more stable quality can be manufactured uniformly in a more stable step.

When the positions of the first end portion 2 a and the second end portion 2 b of the film 2 are obtained at the acquisition point 20 ₁ (before N processes are performed), linear polarization characteristics, for example, have not yet been generated in the film 2 . Therefore, the film 2 is usually a transparent film without an absorption axis. At this time, the position acquisition device 30 having the end detector 31A shown in FIG. 4 is used to detect the first end 2a and the second end 2b of the film 2 on the conveyance roller R, thereby reliably detecting The first end portion 2a and the second end portion 2b of the film 2 are detected. As a result, the difference γ can be calculated more accurately. Here, the case of acquiring point 20 ₁ has been described as an example. However, the same applies to acquiring points 20 ₂ and 20 _3. The position acquisition device 30 having the end detector 31A shown in FIG. 4 can be used to reliably obtain the point 20 1 . The first end portion 2a and the second end portion 2b of the film 2 are detected.

When the film 2 is subjected to dyeing treatment and stretching treatment, the film 2 will be given linear polarization characteristics. When the film 2 is conveyed, tension is given to the film 2 along the conveyance direction of the film 2 . Therefore, when the film 2 is gradually stretched by any one of swelling treatment, dyeing treatment, cross-linking treatment and drying treatment while conveying the film 2 , linearly polarizing characteristics are gradually imparted to the film 2 after the dyeing treatment. In addition, as shown in Figure 1, the drying process is usually performed at the end of N processes. Therefore, when the positions of the first end 2a and the second end 2b of the film 2 are obtained after the dyeing process and the stretching process are performed, the position acquisition device having the end detector 31B shown in FIG. 5 can be used. 30, and reliably detect the first end 2a and the second end 2b. As a result, the difference γ can be calculated more accurately.

As shown in FIGS. 4 and 5 , in the type where the position acquisition device 30 includes the housings 34 and 35 , the light irradiation part 32 and the light detection parts 33 and 36 can be prevented from being corroded by iodine. Since a treatment liquid containing iodine is used in the production of the polarizing film 4 , iodine may be present in the production environment, causing corrosion of, for example, the photodetectors 33 and 36 . In this regard, as shown in FIGS. 4 and 5 , by arranging the light irradiation part 32 and the light detection parts 33 and 36 in the housings 34 and 35 , the aforementioned corrosion caused by iodine can be prevented. It is preferred that the inside of the casings 34 and 35 be pressurized in advance by supplying gas or the like.

The present invention is not limited to the above-mentioned embodiments and various modifications. Of course, it also includes all changes shown in the scope of the patent application and within the meaning and scope equivalent to the scope of the patent application.

The case of manufacturing a polarizing film as an optical film has been exemplified. However, the present invention is also applicable to a manufacturing method and a manufacturing device of an optical film that require monitoring the difference in change in shrinkage ratio between the first width and the second width of the film during the process of manufacturing the optical film from the film. Another example of the optical film includes a protective film, a retardation film, a surface treatment film, an antireflection film, and a diffusion film.

When the N processes include dyeing and stretching, the position acquisition device having the end detector 31B shown in Figure 5 is suitably used in the upstream position to obtain the membrane that has been dyed and stretched. The position of the first end and the second end (the positions of both ends of the membrane). This is because, in this case, the film tends to have linear polarization characteristics when the two ends of the film are positioned at the upstream site. When N processes are performed while conveying the film, the film is gradually stretched as described above. Therefore, the position acquisition device having the end detector 31B can be suitably applied to the case where the upstream position is a position where the first end and the second end of the film that has been dyed are to be detected.

The detection method of the first end portion and the second end portion of the film 2 is not particularly limited to the illustrated method. For example, the first end and the second end can also be detected by measuring machines such as laser displacement meters and LED displacement meters. The entire film 2 may be photographed with a camera or the like, and the positions of the first and second ends may be calculated from the obtained image. As shown in Figure 3, in the method of obtaining the positions of the first end 2a and the second end 2b of the film 2, the detection of the first end 2a is respectively arranged at the first end 2a and the second end 2b. It is sufficient to install the device at the position of the second end portion 2b, so it is preferable from the viewpoint of installation space and machine management (maintenance and inspection, etc.).

The stretching treatment in the stretching treatment part is not limited to the wet stretching method, and a dry stretching method may also be used. In the aforementioned embodiments, the process sequence illustrated for manufacturing the polarizing film may also be Appropriate changes or combinations may be made without departing from the scope of the invention. Each processing unit may have one processing tank or a plurality of processing tanks. The N processes are not limited to the number of illustrated processes.

The definition of the difference between the first rate of change of the first width of the film (the first rate of reduction) and the second rate of change of the second width of the film (the second rate of reduction) is not limited to the illustrated definition, as long as it can be expressed The difference between the first change rate and the second change rate of the membrane between the upstream part and the downstream part is sufficient.

The above-described embodiments and various modifications may be appropriately combined within the scope that does not deviate from the gist of the present invention.

2: Membrane

4: Polarizing film (optical film)

6: Raw material roll

11, 11 ₁ to 11 ₆ : Roller

12, 12 ₁ to 12 ₁₂ : Guide roller

13 ₁ : Swelling treatment department

13 ₂ :Dyeing processing department

13 ₃ : Cross-linking processing department

13 ₄ : Cleaning processing department

13 ₅ : Drying processing department

20, 20 ₁ to 20 ₁₂ : Acquisition points (plural parts)

Claims (28)

A method for manufacturing an optical film, which is a method of manufacturing an optical film by subjecting a long film to N processes (N is an integer of 1 or more); the method is to perform the N processes while transporting the film; during the transport In, the positions of the first end and the second end of the film in the width direction are continuously obtained at a plurality of locations; and the reference position in the width direction of the film and the position of the first end are When the distance between the positions is the first width and the distance between the reference position and the second end is the second width, the distance between the two positions selected from the plurality of positions is determined based on the upstream position of the second position. The first obtained result of the position of the one end and the aforementioned second end portion is used to calculate the aforementioned reference position, and the first width and the second width in the aforementioned upstream portion are calculated based on the aforementioned reference position and the aforementioned first obtained result. , calculate the first width and the second width in the downstream position based on the second obtained result of the position of the aforementioned first end portion and the aforementioned second end portion in the aforementioned reference position and the downstream portion among the aforementioned two locations. , and calculate the first change rate of the first width based on the first width in the aforementioned upstream location and the first width in the aforementioned downstream location, and calculate the first change rate of the first width in the aforementioned upstream location based on the second width in the aforementioned upstream location and the first width in the aforementioned downstream location. The second change rate of the second width is calculated from the two widths, and the difference between the first change rate of the first width and the second change rate of the second width is calculated. The method for manufacturing an optical film according to claim 1, wherein the reference position in the upstream portion is a central position in the width direction of the film in the upstream portion. The method for manufacturing an optical film as described in Item 1 or 2 of the patent application, wherein in at least one combination of the upstream location and the downstream location selected from the plurality of locations, the first change rate and The difference in the aforementioned second change rate is 1.0% or less. The method for manufacturing an optical film as described in Item 1 or 2 of the patent application, wherein the first of all combinations of the upstream portion and the downstream portion is selected from the plurality of locations. The difference between the change rate and the aforementioned second change rate is 1.0% or less. The method for manufacturing an optical film as described in Item 1 or 2 of the patent application, wherein the upstream position is a position before one of the N processes is performed, and the downstream position is where one of the N processes is performed. position after execution. The method for manufacturing an optical film as described in Item 1 or Item 2 of the patent application, wherein the aforementioned N processes include the i-1th process, the i-th process and the i+1th process (i is 2 The above integer); the aforementioned upstream location is between the location of the aforementioned i-1th process and the location of the aforementioned i-th process, and the aforementioned downstream location is between the location of the aforementioned i-th process and the aforementioned i+1th process between positions. The method for manufacturing an optical film as described in item 1 or 2 of the patent application, wherein the aforementioned N processes include the i-1th process and the i-th process (i is an integer above 2); the aforementioned upstream The site is located at the position in the aforementioned i-1th process, and the aforementioned downstream site is between the aforementioned location of the aforementioned i-1th process and the aforementioned location of the i-th process; or the aforementioned upstream site and the aforementioned downstream site are respectively between Between the position of the aforementioned i-1th processing and the position of the aforementioned i-th processing; or the aforementioned upstream position is the position before the aforementioned i-1th processing, and the aforementioned downstream position is in the aforementioned i-1th processing Location. According to the manufacturing method of the optical film described in claim 1 or 2, during the transportation, the imaging unit is used to obtain images of the first end portion and the second end portion of the film. In the manufacturing method of the optical film described in Item 1 or 2 of the patent application, during the aforementioned transportation, the aforementioned second light is obtained based on the brightness of at least one of the reflected light and the transmitted light from the aforementioned film. The position of the end portion and the aforementioned second end portion, wherein the reflected light and the transmitted light from the aforementioned film are caused by the light incident on the aforementioned film. The method for manufacturing an optical film according to claim 1 or 2, wherein the film is transported by a transport roller; and the film on the transport roller is irradiated with light, and the light irradiated is determined by The difference in the brightness of the reflected light of the film and the conveying roller causes the position of the first end portion and the second end portion to be obtained. The manufacturing method of an optical film as described in item 9 of the patent application, wherein the aforementioned transmitted light is the transmitted light from the aforementioned film, wherein the transmitted light from the aforementioned film is incident on the aforementioned film through a polarizing filter. Made of the light of membrane. The manufacturing method of the optical film described in Item 9 of the patent application is to obtain the position of the first end and the second end of the film based on the brightness of the light obtained by the transmitted light passing through the polarizing film. The method for manufacturing an optical film as described in Item 1 or 2 of the patent application, wherein the N treatments include at least one of swelling treatment, dyeing treatment, stretching treatment and drying treatment. The manufacturing method of an optical film as described in Item 1 or Item 2 of the patent application, wherein the aforementioned optical film is a polarizing film. An apparatus for manufacturing an optical film, which is provided with: N processing units (N is an integer equal to or greater than 1) for performing at least a process of imparting optical characteristics to the film; The conveying mechanism conveys the film; the plurality of position acquisition devices are arranged at a plurality of positions on the conveying mechanism, and continuously acquire the width direction of the film being conveyed by the conveying mechanism at the plurality of positions. The positions of the first end and the second end on the film; and the calculation part are: the distance between the reference position in the width direction of the film and the position of the first end is the first width, When the distance between the reference position and the second end is set to the second width, the first end of the upstream position acquisition device among the two position acquisition devices selected from the plurality of position acquisition devices is and the first obtained result of the position of the second end portion, to calculate the aforementioned reference position, and calculate the first width and the second width in the upstream part based on the aforementioned reference position and the aforementioned first obtained result, according to the aforementioned The reference position and the second acquisition result of the position of the first end part and the second end part in the downstream side position acquisition device of the two position acquisition devices are used to calculate the first width and the second width in the downstream part. width, and calculate the first change rate of the first width based on the first width in the aforementioned upstream location and the first width in the aforementioned downstream location, and calculate the first change rate of the first width based on the second width in the aforementioned upstream location and the aforementioned first width in the downstream location. The second change rate of the second width is calculated, and the difference between the first change rate of the first width and the second change rate of the second width is calculated. The apparatus for manufacturing an optical film according to claim 15, wherein the reference position in the arrangement location of the upstream side position acquisition device is a central position in the width direction of the film in the arrangement location. The optical film manufacturing device according to claim 15 or 16, wherein at least one combination of the upstream side position acquisition device and the downstream position acquisition device is selected from the plurality of position acquisition devices. The difference between the first change rate and the second change rate is 1.0% or less. The optical film manufacturing device according to claim 15 or 16, wherein a plurality of combinations of the upstream side position acquisition device and the downstream position acquisition device are selected from the plurality of position acquisition devices. In all combinations, the difference between the aforementioned first change rate and the aforementioned second change rate is less than 1.0%. The optical film manufacturing device described in claim 15 or 16, wherein the upstream position acquisition device is disposed in front of one of the N processing units, and the downstream position acquisition device is Arranged after the aforementioned processing unit. For example, the optical film manufacturing device described in item 15 or 16 of the patent application, wherein the aforementioned N processing units include the i-1 processing unit, the i processing unit and the i+1 processing unit. (i is an integer of 2 or more); the upstream position acquisition device is arranged between the i-1th processing unit and the i-th processing unit; the downstream position acquisition device is arranged between the i-th processing unit between the i+1th processing unit. The optical film manufacturing device described in Item 15 or 16 of the patent application, wherein the aforementioned N processing units include the i-1th processing unit and the i-th processing unit (i is an integer above 2) ; The upstream position acquisition device is arranged at the position of the i-1th processing unit, and the downstream position acquisition device is arranged between the i-1th processing unit and the i-th processing unit; or The aforementioned upstream side position acquisition device and the aforementioned downstream side position acquisition device are respectively arranged between the aforementioned i-1th processing unit and the aforementioned i-th processing unit; or the aforementioned upstream side position acquisition device is arranged between the aforementioned i-1th processing unit. before the processing unit, and the downstream position acquisition device is arranged at the position of the i-1th processing unit. The optical film manufacturing device described in Item 15 or 16 of the patent application, wherein at least one of the plurality of position acquisition devices has a device for photographing at least the first end and the second end of the film. Camera department. The optical film manufacturing device described in claim 15 or 16, wherein at least one of the plurality of position acquisition devices has a light detection part that detects reflected light from the film and at least one of transmitted light, wherein the reflected light and the transmitted light from the aforementioned film are caused by light incident on the aforementioned film. The apparatus for manufacturing an optical film according to claim 15 or 16, wherein at least one position acquisition device among the plurality of position acquisition devices has a light irradiation part that irradiates light to the film. The manufacturing device of an optical film according to claim 24, wherein the conveying mechanism has a conveying roller; the light irradiation unit irradiates light to the film on the conveying roller; and the plurality of position acquisition devices include The at least one position acquisition device obtains the first position of the film based on the difference in brightness of the light reflected from the film and the conveyance roller due to the light irradiated from the light irradiation part to the film on the conveyance roller. The position of the end and the second end. The optical film manufacturing apparatus according to claim 24, wherein a polarizing filter is provided between the light irradiation part and the film. The apparatus for manufacturing an optical film according to claim 23, wherein a polarizing filter is provided between the light detection part and the film. For example, the optical film manufacturing device described in Item 15 or 16 of the patent application, wherein the N processing sections include a swelling treatment section, a dyeing treatment section, a cross-linking treatment section, a stretching treatment section and a drying treatment section. At least any kind of processing department.

Images