JP6122804B2 - Method for curing coating layer, curing apparatus, and method for producing laminated film using the curing method - Google Patents

Description

  The present invention relates to a coating layer curing method and a curing apparatus, and a method for producing a laminated film using the curing method, and more particularly to a mixed gas containing oxygen in an ultraviolet irradiation space when curing a photocurable coating layer by ultraviolet irradiation. Related to the technology to supply.

  In recent years, as an optical film used for a liquid crystal display device, an optical compensation film used as a retardation plate in a liquid crystal cell, an antireflection film for preventing reflection on a liquid crystal display device, glare, etc., an antiglare film Such optical films are typical.

  These optical films can improve the intended function by laminating a plurality of coating layers having different properties, or can have various functions in one optical film. For example, in the case of an antireflection film, a plurality of antireflection layers having different refractive indexes are provided on the hard coat layer provided on the surface of a continuous belt-like support (for example, a flexible plastic film). By doing so, an antireflection film having high scratch resistance can be produced.

  The hard coat layer is generally formed by curing by irradiating the photocurable coating layer with ultraviolet rays. For this curing, an ultraviolet (UV) irradiation device is often employed. Specifically, a coating solution containing a monomer having an ultraviolet curable functional group such as an acryl group is applied to the support to form a photocurable coating layer. Then, a hard-coat layer is formed by polymerizing the photocurable coating layer with ultraviolet rays to form a polymer. Here, if oxygen is present when the photocurable coating layer is irradiated with ultraviolet rays, radicals generated from the polymerization initiator are lost.

  Therefore, in order to accelerate the curing of the photocurable coating layer by irradiating with ultraviolet rays, it is important to reduce the oxygen concentration in the ultraviolet irradiation space as much as possible as in Patent Document 1. Specifically, it is preferable to cover the ultraviolet irradiation space with a casing and introduce an inert gas (for example, nitrogen gas) into the casing to reduce the oxygen concentration in the ultraviolet irradiation space as much as possible.

  However, when the hard coat layer is formed by curing the photocurable coating layer in this way, the amount of residual double bonds on the surface is very small, so that another coating layer (on the hard coat layer ( For example, when the antireflection layer is laminated, the adhesion is reduced. As a result, there is a problem that the antireflection layer is easily peeled off from the hard coat layer after being laminated.

  For example, in Patent Document 2, an oxygen concentration in an ultraviolet irradiation space is reduced to 0 by providing a mixed gas supply device that combines compressed air whose flow rate is adjusted by a valve and nitrogen gas whose flow rate is adjusted by a valve from each pipe. It is proposed to control the oxygen concentration range from 0.05 to 1.0%.

  Thus, the degree of curing of the photocurable coating layer varies depending on the oxygen concentration of the mixed gas supplied to the ultraviolet irradiation space. Therefore, it is necessary to reduce the oxygen concentration of the mixed gas to be supplied when it is desired to impart a high degree of curing to the photocurable coating layer, and to increase the oxygen concentration of the mixed gas when it is desired to impart a low degree of curing.

JP-A-11-104562 JP 2006-95442 A

  By the way, how much the target oxygen concentration of the mixed gas supplied to the ultraviolet irradiation space is to be determined depends on the photo-curing coating liquid formulation (type and amount of curing component, type of polymerization agent, etc.) and coating. It depends on the coating thickness of the layer. In other words, the optimum target oxygen concentration set differs depending on the type of the photocurable coating layer, and it is necessary to cope with various types as compared with the conventional one.

  From such a background, the oxygen concentration region of the mixed gas can be accurately adjusted to the target oxygen concentration in an oxygen concentration region of 0.1 to 10.0% larger than 0.05 to 1.0% of Patent Document 2. It is becoming necessary. In this case, if the variation in the target oxygen concentration is within ± 5% in all the oxygen concentration regions of 0.1% to 10.0%, the photo-curing coating layer has both scratch resistance and adhesion. It can be cured to be satisfactory and there is no problem.

  However, the mixed gas supply apparatus proposed in Patent Document 2 has a problem in that it cannot be accurately adjusted to the target oxygen concentration in all of the wide oxygen concentration region of 0.1 to 10.0%. In particular, in the low oxygen region of the oxygen concentration region, the amount of compressed air is extremely small relative to the amount of nitrogen gas, so it is difficult to accurately adjust the target oxygen concentration by valve control. Even if the compressed air operation valve method (AOV) is used, the ratio of nitrogen gas: compressed air is limited to about 10: 1 (corresponding to 2% oxygen concentration), and the target oxygen concentration is accurately adjusted in the low oxygen region. Difficult to do.

  The present invention has been made in view of such circumstances, and the mixed gas can be accurately adjusted to the target oxygen concentration in all of the wide oxygen concentration region of 0.1 to 10.0%, so that one mixed gas is supplied. An object of the present invention is to provide a coating layer curing method, a curing device, and a method for producing a laminated film using the curing method capable of dramatically increasing the degree of freedom of a target oxygen concentration of a mixed gas that can be adjusted with accuracy by an apparatus. To do.

  In order to achieve the above-described object, the coating layer curing method according to the present invention irradiates the photocurable coating layer formed on the transported belt-shaped support with ultraviolet rays from the irradiation surface of the ultraviolet irradiation device. In the curing method of the coating layer to be cured, the oxygen-containing gas and the inert gas are merged from the respective pipes in the ultraviolet irradiation space between the irradiation surface and the coating layer to be 0.1% to 10.0%. A mixed gas supply step is provided for supplying a mixed gas mixed to a target oxygen concentration in an oxygen concentration region. In the mixed gas supply step, a plurality of valves having different nominal diameters are provided in series or in parallel in the oxygen-containing gas pipe. By adjusting the flow rate of the oxygen-containing gas according to the level of the target oxygen concentration in the oxygen concentration region, by selecting a valve to be used from among a plurality of valves, the mixed gas is mixed with the target oxygen concentration in all regions of the oxygen concentration region. To adjust within 5% ± against.

  Here, the “nominal diameter” means a nominal dimension for expressing the size of the valve, and the smaller the nominal diameter value, the smaller the diameter of the valve flow path.

  The “target oxygen concentration in the oxygen concentration region of 0.1% to 10.0%” differs depending on the type of the photocurable coating layer formed on the support. The optimum target oxygen concentration set according to the product type from the range of 0% oxygen concentration region. “Selecting a valve to be used among a plurality of valves” is not limited to selecting one valve when, for example, three valves having different nominal diameters are provided, and two are selected. This also includes the case of selecting three.

  Further, the optimum target oxygen concentration and the relationship between the target oxygen concentration and the nominal diameter of the valve can be grasped in advance by a preliminary test or the like. “Oxygen-containing gas” refers to a gas containing oxygen, such as compressed air or oxygen gas.

  According to the present invention, the target oxygen in the range of 0.1% to 10.0% by combining the oxygen-containing gas and the inert gas from the respective pipes in the ultraviolet irradiation space between the irradiation surface and the coating layer. In the mixed gas supply process for supplying the mixed gas mixed in the concentration, a plurality of valves having different nominal diameters are provided in series or in parallel on the oxygen-containing gas pipe, and the flow rate adjustment of the oxygen-containing gas to be mixed is a target in the oxygen concentration region. By selecting a valve to be used from among a plurality of valves according to the level of oxygen concentration, the mixed gas was adjusted within ± 5% of the target oxygen concentration in all regions of the oxygen concentration region.

  That is, as the target oxygen concentration in the oxygen concentration region decreases, the nominal diameter of the valve selected from the plurality of valves decreases, and as the target oxygen concentration increases, the nominal diameter of the valve selected from the plurality of valves increases. To do. In this case, for example, when three valves having different nominal diameters are provided, two of the three valves having the smallest nominal diameter and the next smallest valve are selected as the target oxygen concentration in the oxygen concentration region decreases. Including selection. Similarly, as the target oxygen concentration increases, the selection includes two of the three valves having the largest nominal diameter and the second largest valve among the three valves.

  As a result, even in a wide oxygen concentration range of 0.1% to 10.0%, the mixed gas can be accurately adjusted with respect to the target oxygen concentration. The degree of freedom of the target oxygen concentration of the mixed gas that can be adjusted can be dramatically increased. Therefore, it is possible to cope with various types of photo-curing coating layers with one mixed gas supply device from a variety requiring a low target oxygen concentration to a variety requiring a high target oxygen concentration.

  In this case, the variation with respect to the target oxygen concentration needs to be within ± 5%, preferably within ± 1%, and more preferably within ± 0.1%.

  In the coating layer curing method of the present invention, the plurality of valves are preferably needle valves.

  Although the present invention can be applied to various valves, the needle valve is suitable for adjusting a valve with a small flow rate, and among needle valves having different nominal diameters for adjusting the flow rate of an oxygen-containing gas having a small mixing ratio with respect to the mixed gas. By selecting the valve to be used, the target oxygen concentration can be adjusted with higher accuracy even in a wide range of oxygen concentration regions.

  In the coating layer curing method of the present invention, the oxygen concentration of the supplied mixed gas is measured, and the measured value is compared with the target oxygen concentration so that the measured value changes within the target oxygen concentration ± 5%. Of these valves, it is preferable to feedback control the opening degree of the valve in use.

  Thus, by providing feedback control means for each valve having a different nominal diameter, the target oxygen concentration can be adjusted with higher accuracy even in a wide range of oxygen concentration regions.

  In this case, the accuracy can be further improved by combining feedback control with the needle valve.

  In the coating layer curing method of the present invention, it is preferable that the plurality of valves are arranged in series with the pipe, and the larger nominal valve is disposed upstream of the smaller nominal diameter valve.

  This is because a valve that is not used among a plurality of valves needs to be fully opened. Therefore, by disposing a valve with a large nominal diameter upstream of a valve with a small nominal diameter, it is possible to prevent a decrease in gas pressure due to the valve itself disposed at the upstream position. It can be performed with high accuracy.

  In order to achieve the above-described object, the coating layer curing device according to the present invention includes an ultraviolet irradiation device that irradiates and cures a photocurable coating layer formed on a transported belt-like support by ultraviolet rays. In a coating layer curing apparatus, comprising: a mixed gas supply device that supplies a mixed gas of an oxygen-containing gas and an inert gas to an ultraviolet irradiation space between the irradiation surface of the ultraviolet irradiation device and the coating layer; The oxygen-containing gas pipe of the supply device is provided with a plurality of valves having different nominal diameters in series or in parallel as flow rate adjusting valves.

  According to the present invention, since a plurality of valves having different nominal diameters are provided in series or in parallel in the oxygen-containing gas pipe in the mixed gas supply device, the flow rate adjustment of the oxygen-containing gas to be mixed is performed in the oxygen concentration region. By selecting a valve to be used from among a plurality of valves according to the level of the target oxygen concentration, the mixed gas can be adjusted to within ± 5% of the target oxygen concentration in all regions of the oxygen concentration region. it can.

  As a result, even in a wide oxygen concentration range of 0.1% to 10.0%, the mixed gas can be accurately adjusted with respect to the target oxygen concentration. The degree of freedom of the target oxygen concentration of the mixed gas that can be adjusted can be dramatically increased. Therefore, it is possible to cope with various types of photo-curing coating layers with one mixed gas supply device from a variety requiring a low target oxygen concentration to a variety requiring a high target oxygen concentration.

  In the present invention, the plurality of valves are preferably needle valves.

  In the present invention, the oxygen concentration meter that measures the oxygen concentration of the supplied mixed gas, and the measured value is compared with the target oxygen concentration so that the measured value changes within the target oxygen concentration ± 5%. It is preferable to include feedback control means for controlling the opening degree of the valve in use among the plurality of valves. Thereby, even in a wide oxygen concentration region, the target oxygen concentration can be adjusted with higher accuracy.

  In the present invention, it is preferable that the plurality of valves are arranged in series with the pipe, and that the valve having the larger nominal diameter is arranged upstream of the valve having the smaller nominal diameter. Thereby, the valve control of the small nominal diameter valve arranged at the downstream position can be performed with high accuracy.

  In order to achieve the above-mentioned object, a method for producing a laminated film according to the present invention irradiates a photocurable coating layer coated on a belt-shaped support to be conveyed from an irradiation surface of an ultraviolet irradiation device. A curing step of curing the photocurable coating layer, and a laminating step of coating and laminating another coating layer on the photocurable coating layer after curing, and a method for producing a laminated film In the curing step, the oxygen-containing gas and the inert gas are merged from the respective pipes in the ultraviolet irradiation space between the irradiation surface and the coating layer, and the oxygen concentration region of 0.1% to 10.0% is obtained. A mixed gas supply step for supplying a mixed gas mixed at a target oxygen concentration, and in the mixed gas supply step, a plurality of valves having different nominal diameters are provided in series or in parallel in the piping of the oxygen-containing gas to mix the oxygen-containing gas to be mixed Adjust the flow rate in the oxygen concentration area By selecting a valve to be used among a plurality of valves according to the level of the definitive target oxygen concentration, in all areas of the oxygen concentration region is adjusted within 5% ± the mixed gas with respect to the target oxygen concentration.

  As described above, by incorporating the coating layer curing method of the present invention into the method for producing a laminated film, even when the optimum target oxygen concentration required for the photocurable coating layer varies widely, the target can be accurately obtained. The oxygen concentration can be adjusted. As a result, the degree of freedom of the target oxygen concentration of the mixed gas that can be adjusted by one mixed gas supply device can be dramatically increased, so that the scratch resistance is independent of the coating liquid formulation and coating thickness of the photocurable coating layer. It becomes possible to produce a laminated film that satisfies the above and adhesiveness.

  According to the coating layer curing method and curing apparatus of the present invention, the mixed gas can be accurately adjusted to the target oxygen concentration in all of a wide range of oxygen concentration of 0.1 to 10.0%. The degree of freedom of the target oxygen concentration of the mixed gas that can be accurately adjusted by the apparatus can be dramatically increased.

  Therefore, according to the method for producing a laminated film of the present invention, there is only one product from a variety requiring a low target oxygen concentration to a variety requiring a high target oxygen concentration in order to satisfy both scratch resistance and adhesion. The mixed gas supply device can be used for various types of photocurable coating layers. Therefore, it becomes possible to produce a laminated film that satisfies both the scratch resistance and the adhesiveness regardless of the coating liquid formulation and coating thickness of the photocurable coating layer.

The side view of the ultraviolet irradiation device in the curing device of the embodiment of the present invention The block diagram of the mixed gas supply apparatus in the hardening apparatus of embodiment of this invention Configuration diagram with multiple needle valves with different nominal diameters arranged in parallel Configuration diagram with feedback control means for multiple needle valves with different nominal diameters Overall configuration diagram showing an example of a production line for a hard coat layer in a method for producing a laminated film Explanatory drawing explaining the layer structure of an antireflection film as an example of a laminated film Configuration diagram in which valve temperature maintenance means is provided for multiple needle valves with different nominal diameters Explanatory drawing explaining the test result of the Example and comparative example of this invention

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a coating layer curing method and a curing apparatus according to the present invention and a method for producing a laminated film using the curing method will be described in detail below with reference to the accompanying drawings.

  As shown in FIGS. 1 and 2, the coating layer curing device 5 according to the embodiment of the present invention mainly includes an ultraviolet irradiation device 10 and a mixed gas supply device 22.

  FIG. 1 is a side view showing an example of an ultraviolet irradiation device 10 in which two ultraviolet lamp houses 16 and 16 are arranged in series along a conveyance line of a web 12 (support). The number of the ultraviolet lamp houses 16 is not limited to two, but may be one or three or more.

  As shown in FIG. 1, the ultraviolet irradiation device 10 includes a pair of support rollers 14 and 14 that support a continuously conveyed web 12, a pair of ultraviolet lamp houses 16 and 16, and an irradiation surface 16 </ b> A of the ultraviolet lamp house 16. The projecting member 20 extends from the peripheral edge of the four circumferences toward the web 12 and forms an ultraviolet irradiation space 18 between the irradiation surface 16 </ b> A and the web 12.

  The ultraviolet lamp house 16 is a means for irradiating the photocurable coating layer formed on the surface of the web 12 with ultraviolet rays to cure the coating layer, and has a square box shape with an open front end surface on the support roller 14 side. Have Inside the ultraviolet lamp house 16, an ultraviolet lamp 16B and a reflection mirror 16C are disposed. And quartz glass is provided in the open | released front end surface of the ultraviolet lamp house 16, and the irradiation surface 16A is formed.

  The support roller 14 is a roller member in which the web 12 is disposed opposite to the irradiation surface 16A of the ultraviolet lamp house 16 and wraps and supports the continuously conveyed web 12, and has a length substantially equal to the width of the web 12 (this example). The width of the web 12 is slightly longer).

  The overhanging member 20 includes a pair of long side plates 20A and 20A arranged to face each other along the axial direction of the support roller 14, and a short side plate 20B that closes both sides (front and back sides in FIG. 1) of the long side plates 20A and 20A. , 20B and a top plate 20C that closes the tip surfaces of the pair of ultraviolet lamp houses 16,16. Further, the front end portions of the long side plate 20A and the short side plate 20B have folded pieces 20D and 20D extending substantially at right angles to the support roller 14 side. Needless to say, the lengths of the folded pieces 20D and 20D do not come into contact with the surface of the web 12 wound around and supported by the support roller 14. It is preferable that the distance between the tips of the folded pieces 20D and 20D and the surface of the web 12 is 5 mm or less. As a result, a substantially hermetically sealed ultraviolet irradiation space 18 surrounded by the projecting member 20 is formed between the irradiation surface 16A and the web 12 supported by being wound around the pair of support rollers 14.

  Although there is no restriction | limiting in particular in the material of the overhang | projection member 20, The resin material (for example, polyimide sheet) which has 150 degreeC or more heat resistance is preferable for the front-end | tip part of the folding pieces 20D and 20D. Alternatively, it is preferably formed of a rubber material having heat resistance of 150 ° C. or higher (for example, silicone rubber, fluorine rubber, chlorosulfonated polyethylene rubber, etc.).

  By setting it as such a structure, the front-end | tip part of the folding pieces 20D and 20D is formed with the member which has heat resistance. Further, since the distance between the tip of the folded pieces 20D and 20D and the surface of the web 12 is 5 mm or less (for example, 2 mm, 3 mm, etc.), the oxygen concentration in the ultraviolet irradiation space 18 is hardly affected by outside air. It is easy to stabilize.

  Further, a pair of mixed gas supply ports 20E and 20F supplied from a mixed gas supply device 22 (see FIG. 2), which will be described later, is formed at a substantially central position of the opposing long side plate 20A of the projecting member 20.

  Then, the mixed gas adjusted to the target oxygen concentration with the oxygen-containing gas and the inert gas is supplied from the mixed gas supply device 22 to the ultraviolet irradiation space 18 of the ultraviolet irradiation device 10 configured as described above. Accordingly, the curing process is performed by irradiating the photocurable coating layer with ultraviolet rays while supplying the mixed gas having the target oxygen concentration to the ultraviolet irradiation space 18 of the ultraviolet irradiation device 10.

  FIG. 2 is a configuration diagram showing an example of the mixed gas supply device 22, in which the oxygen-containing gas and the inert gas are merged into the ultraviolet irradiation space 18 of the ultraviolet irradiation device 10 from the respective pipes and mixed to the target oxygen concentration. This is a device for supplying the mixed gas.

  The target oxygen concentration of the mixed gas supplied to the ultraviolet irradiation space 18 is determined depending on the formulation of the coating solution for the photo-curing coating layer (type and amount of curing component, type of polymerizing agent, etc.) and coating of the coating layer. It depends on the thickness. That is, the optimum target oxygen concentration set by the type of the photocurable coating layer formed on the web 12 shifts in the range of 0.1% to 10.0%.

  Therefore, the mixed gas supply device 22 is required to accurately adjust the mixed gas to the target oxygen concentration over a wide range of oxygen concentration of 0.1% to 10.0%.

  The mixed gas supply device 22 of the present embodiment will be described below using an example in which compressed air is used as the oxygen-containing gas and nitrogen gas is used as the inert gas. Further, an example in which the ultraviolet irradiation device 10 is installed in the air conditioning clean room 24 and the mixed gas supply device 22 is installed in the power chamber 26 will be described.

  As shown in FIG. 2, the mixed gas supply device 22 is configured by a mixed gas supply line including two lines so that the mixed gas can be supplied to the two supply ports 20 </ b> E and 20 </ b> F of the ultraviolet irradiation device 10. The mixed gas supply line includes a nitrogen gas line 28 and a compressed air line 30.

  The nitrogen gas line 28 is branched into a first nitrogen pipe 32A and a second nitrogen pipe 32B in the middle of the nitrogen pipe 32, and the nitrogen gas from the nitrogen cylinder 34 is divided into the first nitrogen pipe 32A and the second nitrogen pipe 32B. Is done. The nitrogen pipe 32 before branching is provided with an on-off valve 36, a pressure gauge 38, and a pressure adjustment valve 40, and the pressure of nitrogen gas flowing through the nitrogen gas line 28 is adjusted.

  The first nitrogen pipe 32A and the second nitrogen pipe 32B are respectively provided with flow rate adjusting valves 42A and 42B and flow meters 44A and 44B in order from the nitrogen cylinder 34 side. Thereby, the flow rate of nitrogen gas for preparing the mixed gas is adjusted. The flow rate adjusting valves 42A and 42B are not particularly limited, but will be described below with an example of a disk valve.

  The first nitrogen pipe 32A is connected to the first supply port 20E of the ultraviolet irradiation device 10, and the second nitrogen pipe 32B is connected to the second supply port 20F.

  On the other hand, in the compressed air line 30, the compressed air pipe 46 is branched into the first compressed air pipe 46A and the second compressed air pipe 46B in the middle, and the compressed air from the compressor 48 is compressed into the first compressed air pipe 46A and the second compressed air pipe 46B. The air is divided into the air pipe 46B. The compressed air pipe 46 before branching is provided with an on-off valve 50, a pressure gauge 52, and a pressure adjusting valve 54, and the pressure of the compressed air flowing through the compressed air line 30 is adjusted.

  The branched first compressed air piping 46A communicates with the first nitrogen piping 32A, and the second compressed air piping 46B communicates with the second nitrogen piping 32B. Thereby, the compressed gas flowing through the first compressed air pipe 46A (or the second compressed air pipe 46B) merges with the nitrogen gas flowing through the first nitrogen pipe 32A (or the second nitrogen pipe 32B), and the two gases are mixed. Is done.

  The first compressed air pipe 46A is provided with needle valves 56A, 58A, 60A in series as a plurality of flow rate adjusting valves having different nominal diameters. Similarly, needle valves 56B, 58B, and 60B are provided in series in the second compressed air pipe 46B as a plurality of flow rate adjustment valves having different nominal diameters.

  The types of flow rate adjusting valves having different nominal diameters provided in the first compressed air pipe 46A and the second compressed air pipe 46B are not particularly limited, but in the present embodiment, an example of a needle valve will be described.

  That is, the first compressed air pipe 46A is provided with a first needle valve 56A, a second needle valve 58A, and a third needle valve 60A in order from the compressor 48. A flow meter 62A is provided downstream of the third needle valve 60A in the compressed air flow direction.

  Similarly, a first needle valve 56B, a second needle valve 58B, and a third needle valve 60B are provided in order from the compressor 48 in the second compressed air pipe 46B. A flow meter 62B is provided downstream of the third needle valve 60B in the compressed air flow direction.

  Here, the “needle valve” is a valve that adjusts the opening of the orifice hole by rotating the needle pin back and forth to the orifice with a certain hole, thereby changing the flow rate of gas or fluid. Say.

  And in order to implement the hardening method of a photocurable coating layer using the ultraviolet irradiation device 10 of the above-mentioned hardening apparatus 5, the mixed gas supply process is performed using the mixed gas supply apparatus 22. FIG.

  That is, in the first compressed air piping 46A and the second compressed air piping 46B, a plurality of needle valves 56A having different nominal diameters according to the level of the target oxygen concentration in the oxygen concentration region of 0.1% to 10.0%. By selecting a valve to be used from 58A, 60A (56B, 58B, 60B), the mixed gas is adjusted within ± 5% of the target oxygen concentration in all the oxygen concentration regions.

  For example, as the plurality of needle valves provided in the first compressed air pipe 46A and the second compressed air pipe 46B, the nominal diameter of the first needle valves 56A and 56B is 15A, and the nominal diameter of the second needle valves 58A and 58B is 6A. The nominal diameter of the third needle valves 60A, 60B can be 1A.

  In this case, the nominal diameters of the first needle valves 56A and 56B, the second needle valves 58A and 58B, and the third needle valves 60A and 60B may be larger on the upstream side when viewed from the flow direction of the compressed air. preferable. This is because, in selecting the needle valve to be used among the three needle valves 56A, 58A, 60A (or 56A, 58A, 60A) in the first compressed air pipe 46A (or the second compressed air pipe 46B), This is because a needle valve that is not used needs to be fully opened. For example, when the third needle valve 60A (or 60B) having the smallest nominal diameter is used, the needle valve 56A, 58A (or 56B, 58B) having the large nominal diameter is replaced with the third needle valve 60A (or 60B) having the small nominal diameter. ) To the upstream side. Thereby, the pressure drop by the needle valve which is not used can be suppressed, and the valve control of the used third needle valve 60A can be performed with higher accuracy.

  However, when three or more needle valves are arranged in series, for example, needle valves having the same nominal diameter such as nominal diameters 15A, 1A, and 1A can be arranged from the upstream side.

  Further, the plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) are not limited to three as shown in FIG. 2, and may be two or more.

  Furthermore, the plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) is not limited to being arranged in series, and as shown in FIG. 3, the plurality of needle valves 56A, 58A, 60A ( 56B, 58B, 60B) can also be arranged in parallel.

  And the needle valve to be used can be selected from the plurality of needle valves arranged as shown in FIGS. 2 and 3 as follows.

  The first selection method is a method of selecting one needle valve to be used from among a plurality of needle valves in accordance with the target oxygen concentration level in the oxygen concentration region (hereinafter referred to as “valve proper use method”).

  The second selection method is a method of selecting and combining a plurality of needle valves among a plurality of needle valves according to the level of the target oxygen concentration in the oxygen concentration region (hereinafter referred to as “valve combination method”).

  The valve selection method selects the third needle valve 60A, 60B having the smallest nominal diameter among the plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) as the target oxygen concentration in the oxygen concentration region decreases. . Conversely, as the target oxygen concentration in the oxygen concentration region increases, the first needle valve 56A, 56B having the largest nominal diameter is selected from the plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B).

  Further, in the valve combination method, the third needle valves 60A, 60B having the smallest nominal diameter among the plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) as the target oxygen concentration in the oxygen concentration region decreases. Then, the second needle valves 58A and 58B having the smaller nominal diameter are selected.

  Conversely, as the target oxygen concentration in the oxygen concentration region increases, the first needle valves 56A, 56B having the largest nominal diameter among the plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) are called next. The second needle valves 58A and 58B having a large diameter are selected.

  Also, in the valve combination method, when a plurality of needle valves are selected in a state where a plurality of needle valves are arranged in series as shown in FIG. 2, the gas flow rate is roughly adjusted with a needle valve having a large upstream diameter. A fine adjustment with a needle valve having a small nominal diameter on the downstream side is preferable.

  As shown in FIG. 3, when a plurality of needle valves are selected in a state where the plurality of needle valves are arranged in parallel, it is preferable to appropriately adjust the opening degrees of the plurality of needle valves.

  The optimum target oxygen concentration set according to the type of the photocurable coating layer and the relationship between the target oxygen concentration and the nominal diameter of the needle valve can be grasped in advance by a preliminary test or the like. In addition, whether to select the proper valve use method or the valve combination method according to the oxygen concentration region can be determined in advance by a preliminary test or the like.

  As a result, even in a wide oxygen concentration range of 0.1% to 10.0%, the mixed gas can be accurately adjusted to the target oxygen concentration. The degree of freedom of the target oxygen concentration of the mixed gas can be dramatically increased. Therefore, it is possible to cope with various types of photo-curing coating layers with one mixed gas supply device 22 from a variety requiring a low target oxygen concentration to a variety requiring a high target oxygen concentration.

In order to adjust a mixed gas having a target oxygen concentration of 0.1%, which is the lower limit value of the oxygen concentration region, by mixing nitrogen gas and compressed air, a compressed air flow rate of 0.1 m with respect to a nitrogen gas flow rate of 100 m ³ / h. ³ / h is required. Further, the target oxygen concentration is an upper limit value of the oxygen concentration region is adjusted with 10% of a mixed gas by mixing with the compressed air and nitrogen gas, the nitrogen gas flow rate of 90m 3 / ^h compression to the air flow rate 10 m ³ / It is necessary to set h.

That is, the nitrogen gas amount can cover a wide oxygen concentration range of 0.1% to 10.0% by adjusting the flow rate in a small flow rate range of 90 m ³ / h to 100 m ³ / h. However, compressed air amount, it is necessary to flow rate adjustment by 0.1m ³ / ^{10m 3/100} times the flow rate range to the upper limit of h from the lower limit value of h. Therefore, when the flow rate of compressed air is adjusted with a single valve as in the prior art, the variation of the target oxygen concentration within a wide range of oxygen concentration of 0.1% to 10.0% is within ± 5%. An area that cannot be suppressed is generated.

  On the other hand, like the mixed gas supply device 22 of the embodiment of the present invention, the first compressed air pipe 46A and the second compressed air pipe 46B are provided with a plurality of needle valves 56A, 58A, 60A ( 56B, 58B, 60B). Then, the needle valve to be used is selected from among the plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) according to the level of the target oxygen concentration in the oxygen concentration region (0.1% to 10.0%). As a result, it is possible to accurately adjust within ± 5% of the target oxygen concentration with one mixed gas supply device 22.

  The mixed gas supply device 22 of FIG. 4 is provided with a feedback control means for each of a plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) having different nominal diameters. FIG. 4 shows a case where a plurality of needle valves having different nominal diameters are arranged in series, but feedback control means can also be provided when they are arranged in parallel as shown in FIG.

  As shown in FIG. 4, oxygen concentration meters 64A and 64B for measuring the oxygen concentration of the mixed gas are provided in the first nitrogen pipe 32A and the second nitrogen pipe 32B through which the mixed gas flows. The oximeters 64A and 64B are connected to the controller 66 by signal cables or wirelessly, and the measurement values measured by the oximeters 64A and 64B are sent to the controller 66. The controller 66 is connected to a drive unit (not shown) for adjusting the opening amounts of a plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) having different nominal diameters by a signal cable or wirelessly.

  As the oxygen concentration meter, for example, a low concentration zirconia oxygen concentration meter OX400 manufactured by Yokogawa Electric Co., Ltd. or a high-functional zirconia oxygen concentration meter LC-860 manufactured by Toray Engineering Co., Ltd. may be used. it can. As a measurement location, as shown in FIG. 4, it is preferable to measure the oxygen concentration of the mixed gas immediately before being supplied to the ultraviolet irradiation device 10.

  Moreover, the target oxygen concentration of the mixed gas can be input to the controller 66 from an input means (not shown), and the measured value measured by the oxygen concentration meters 64A and 64B is compared with the input target oxygen concentration. The controller 66 then includes a plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) such that the oxygen concentration of the mixed gas measured by the oxygen concentration meters 64A, 64B changes within the target oxygen concentration ± 5%. ) Feedback control of the opening of the needle valve in use.

  In this way, in addition to the operation of selecting the needle valve to be used among the plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) having different nominal diameters, feedback control means is provided for each needle valve. This makes it possible to adjust the oxygen concentration of the mixed gas with an accuracy within the target oxygen concentration ± 0.1%.

  Next, a method for producing a laminated film incorporating the coating layer curing device 5 configured as described above will be described.

  FIG. 5 is an example of the overall configuration of a production line 75 for forming a hard coat layer in an apparatus for producing an antireflection film as a laminated film. FIG. 6 shows an example of the layer structure of the antireflection film 3, in which a low refractive index layer is laminated as the antireflection layer 2 on the hard coat layer 1 formed on the web 12.

  As shown in FIG. 5, the belt-like web 12 is continuously sent out from the feeder 76 to the production line, and various treatments are performed in the following order to form the hard coat layer 1.

  The web 12 delivered from the delivery device 76 is guided by the guide roller 78 and sent to the dust remover 80, and foreign matters such as dust adhering to the surface of the web 12 are removed (web dust removal step).

  Next, the web 12 is sent to the gravure coating coater 82, and a photocurable coating solution for forming the hard coat layer 1 is applied onto the web 12. Thereby, a photocurable coating layer is formed on the web 12 (photocurable coating layer coating step).

  The gravure coating coater 82 includes a gravure roller 82A having a cell formed on the roller surface, a liquid receiving pan 82B provided below the gravure roller 82A, and a surplus portion of the coating liquid before coating. The doctor blade 82C is scraped off.

  The continuously conveyed web 12 is supported in parallel with the gravure roller 82A by the upstream guide roller 82D and the downstream guide roller 82E.

Since the gravure coating coater 82 is particularly effective for thin layer coating, for example, it is suitable for a production line that performs ultra-thin layer coating with a wet coating amount of 5 ml / m ² or less (wet film thickness during coating is 5 μm or less). Applicable.

  As a coating method, in addition to the above-described gravure coating coater 82, a bar coater, a roll coater (transfer roll coater, reverse roll coater, etc.), die coater, extrusion coater, fountain coater, curtain coater, dip coater, spin coater, spray coater Or a slide hopper etc. are employable.

  Next, the web 12 on which the photocurable coating layer is formed is sequentially sent to the drying zone 84 and the heating zone 86, and the organic solvent containing the photopolymerization initiator in the photocurable coating solution is dried into the drying zone 84. And evaporates by passing through the heating zone 86 (drying / heating step of the photocurable coating layer). The drying method of the drying zone 84 and the heating method of the heating zone 86 are not particularly limited.

  Next, the photocurable coating layer is dried and heated, and the web 12 is sent to the ultraviolet irradiation device 10 that is the curing device 5 for curing the photocurable coating layer. The photocurable coating layer is cured by irradiating ultraviolet rays from the irradiation surface 16A of the ultraviolet irradiation device 10 (curing step of the photocurable coating layer). In addition, the ultraviolet irradiation device 10 of FIG. 5 is illustrated with one ultraviolet lamp house 16 and one support roller 14.

  Finally, the web 12 on which the photocurable coating layer has been cured is wound around a winder 88. Thereby, the hard coat layer 1 is formed on the web 12.

  Then, another coating layer (for example, an antireflection layer) is applied to the cured web 12 on which the hard coat layer 1 is formed by the same production line as in FIG. As another coating layer, in addition to the antireflection layer, an optical functional layer such as an optical compensation layer and an antiglare layer, and any coating layer other than the optical functional layer are also included in the present invention.

  Since the mixed gas supply device 22 of the present embodiment is incorporated as a device for supplying the mixed gas containing oxygen to the ultraviolet irradiation device 10 of the production line 75 described above, an oxygen concentration region of 0.1 to 10.0% Thus, the mixed gas can be accurately adjusted to the target oxygen concentration.

  As a result, the degree of freedom of the target oxygen concentration of the mixed gas that can be adjusted by one mixed gas supply device 22 can be dramatically increased, so that the scratch resistance can be improved regardless of the coating liquid formulation and coating thickness of the hard coat layer 1. It becomes possible to produce a laminated film satisfying adhesion.

  Next, another aspect of the mixed gas supply device 22 will be described with reference to FIG.

  FIG. 7 shows a preferred embodiment of the mixed gas supply device 22 when the production line 75 for forming the hard coat layer 1 is continuously operated for a long time (for example, for 3 days).

  The mixed gas supply device 22 shown in FIG. 7 is basically the same as FIG. 2, but the valve product temperatures of a plurality of needle valves 56A, 58A, 60A (56B, 58B, 60B) having different nominal diameters are made constant. A valve product temperature maintaining means 68 for maintaining is provided.

  The valve product temperature maintaining means 68 includes a heat insulating casing 70 with a heater 70A surrounding the needle valves 56A, 58A, 60A (56B, 58B, 60B), a temperature sensor 72 provided in the heat insulating casing 70, and a temperature sensor. And a temperature control means 74 for controlling the heater 70A so that the inside of the heat insulating casing 70 (temperature environment around the valve) is maintained at a constant temperature (for example, normal temperature) based on the measured temperature 72. The valve product temperature maintaining means 68 is not limited to the above configuration, and any means may be used as long as the valve product temperature can be maintained constant.

  Thus, by providing the valve product temperature maintaining means 68 to a plurality of needle valves having different nominal diameters, the target oxygen concentration can be accurately adjusted in a wide range of oxygen concentration of 0.1 to 10.0%. In addition, the target oxygen concentration once adjusted can be prevented from changing over time due to the temperature environment of the power chamber 26 in which the needle valve is installed.

  It is also possible to combine the feedback control means shown in FIG. 7 with the valve product temperature maintaining means 68. In the present embodiment, the example of compressed air has been described as the oxygen-containing gas. However, oxygen gas may be used.

  Next, preferred embodiments of the web 12 and the hard coat layer 1 will be described.

  The web 12 is preferably a plastic film. Examples of the plastic film include cellulose esters (eg, triacetylcellulose, diacetylcellulose, propionylcellulose, butyrylcellulose, acetylpropionylcellulose, nitrocellulose) and polyolefins (eg, polypropylene, polyethylene, polymethylpentene, triacetylcellulose, In addition, since polyolefin has a small retardation and high optical uniformity, it is preferable for use as a polarizing plate. In particular, when used in a liquid crystal display device, triacetyl cellulose is preferable.

  The hard coat layer 1 is provided on the surface of the web 12 in order to impart physical strength to the laminated film.

  The hard coat layer 1 is preferably formed by a crosslinking reaction or a polymerization reaction of a photocurable coating layer containing an ionizing radiation curable compound. For example, it can be formed by applying a photocurable compound containing an ionizing radiation curable polyfunctional monomer or polyfunctional oligomer on the web 12 and causing the polyfunctional monomer or polyfunctional oligomer to undergo a crosslinking reaction or a polymerization reaction. it can. Further, in order to adjust the refractive index and strength of the hard coat layer 1, inorganic fine particles may be included.

  The functional group of the ionizing radiation-curable polyfunctional monomer or polyfunctional oligomer is preferably a light, electron beam, or radiation polymerizable group, and among them, a photopolymerizable functional group is preferable.

  Examples of the photopolymerizable functional group include unsaturated polymerizable functional groups such as a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among them, a (meth) acryloyl group is preferable.

  It is preferable to use a photopolymerization initiator for the polymerization reaction of the photopolymerizable polyfunctional monomer. As the photopolymerization initiator, a photoradical polymerization initiator and a photocationic polymerization initiator are preferable, and a photoradical polymerization initiator is particularly preferable.

  The mixed gas supply device shown in FIG. 2 that selects a valve to be used from among a plurality of needle valves having different nominal diameters for adjusting the flow rate of the compressed air can be accurately adjusted in an oxygen concentration region of 0.1 to 10.0%. The degree of freedom of the target oxygen concentration of the mixed gas was examined (Examples 1 to 4).

  In addition, using a conventional mixed gas supply device that adjusts the flow rate of compressed air with a single valve, the degree of freedom of the target oxygen concentration of the mixed gas that can be accurately adjusted in the oxygen concentration range of 0.1 to 10.0% It investigated (Comparative Examples 1-2).

<Test conditions>
In the test, five target oxygen concentrations of 0.1%, 1%, 3%, 6%, and 10% were set in the oxygen concentration region of 0.1 to 10.0%. And the precision of the valve control in each target oxygen concentration at the time of performing the compressed air flow rate adjustment method of Comparative Examples 1-2 and Examples 1-4 shown below was investigated.

That is, a compressed air pipe is connected to the nitrogen pipe, and a nitrogen flow rate flowing through the nitrogen pipe is controlled between 90 and 100 m ³ / h, and a compressed flow rate flowing between the compressed air pipes is between 0.1 and 10 m ³ / h. The valve was controlled. In addition, the nitrogen flow rate adjustment method was performed by providing a disk valve in nitrogen piping in Comparative Examples 1-2 and Examples 1-4. In Examples 1 to 4, the above-described “valid use method” was used as a valve selection method.

<Compression air flow rate adjustment method>
Comparative Example 1 is a case where the flow rate of compressed air is adjusted by providing only a needle valve with a nominal diameter of 1A in the compressed air piping.

  Comparative Example 2 is a case where the flow rate of compressed air is adjusted by providing only a needle valve with a nominal diameter of 15A in the compressed air piping.

  -Example 1 ... Two needle valves with nominal diameters of 1A and 15A are arranged in series on the compressed air piping, and the needle valve to be used is selected from the two needle valves to adjust the flow rate of the compressed air. This is the case.

  Example 2 This is a case where feedback control means is provided in each of the two needle valves of Example 1 to adjust the flow rate of the compressed air.

  [Example 3] Three needle valves having nominal diameters of 1A, 6A, and 15A are arranged in series in a compressed air pipe, and one of the three needle valves to be used is selected to be compressed air. In this case, the flow rate is adjusted.

  Example 4 is a case where feedback control means is provided for each of the three needle valves of Example 3 to adjust the flow rate of the compressed air.

  In Examples 1 to 4, the needle valve having a larger nominal diameter was arranged upstream in the flow direction of the compressed air. Further, the flow rate of nitrogen gas was adjusted with one disk valve provided in a pipe through which nitrogen gas flows.

<Evaluation method of test results>
A: The gas mixture can be adjusted to within the target oxygen concentration ± 0.1%, which is acceptable.
B: The gas mixture can be adjusted within the target oxygen concentration ± 1%, which is acceptable.
C: The gas mixture can be adjusted within the target oxygen concentration ± 5%, which is acceptable.
D: The mixed gas could not be adjusted within the target oxygen concentration ± 5%, and failed.

<Test results>
The test results are shown in the table of FIG.

  As can be seen from the table of FIG. 8, Comparative Example 1 can cover the target oxygen concentration within ± 5% in the range of 0.1% to 3.0% in the oxygen concentration region of 0.1 to 10.0%. The range of 6.0% to 10.0% cannot be covered. That is, it can be seen that the variation exceeds ± 5% between 3.0% and 6.0%.

  Further, Comparative Example 2 can cover the target oxygen concentration within ± 5% in the range of 6.0% to 10.0% in the oxygen concentration region of 0.1 to 10.0%. The range of 0.0% cannot be covered.

  On the other hand, Examples 1-4 can cover the target oxygen concentration within ± 5% for all of the oxygen concentration regions of 0.1 to 10.0%. In particular, as in Examples 2 and 4, it was possible to achieve remarkably good accuracy within the target oxygen concentration ± 0.1% by using feedback control together.

  From this result, the curing apparatus provided with the mixed gas supply device of the present embodiment can accurately adjust the mixed gas to the target oxygen concentration in all of the wide oxygen concentration region of 0.1 to 10.0%. The degree of freedom of the target oxygen concentration of the mixed gas that can be accurately adjusted with one mixed gas supply device can be dramatically increased.

  Therefore, if the curing method and apparatus of the present invention are incorporated into a laminated film production line, a high target oxygen concentration is required from a variety that requires a low target oxygen concentration to satisfy both scratch resistance and adhesion. A single mixed gas supply device can handle various types of hard coat layers. Therefore, it is possible to produce a laminated film satisfying the scratch resistance and adhesion regardless of the coating liquid formulation and the coating thickness of the hard coat layer.

  In this embodiment, the needle valve is described as an example of a valve having a different nominal diameter. However, when other valves are used, the oxygen concentration region that can cover the target oxygen concentration within ± 5% is different from that of the needle valve, but the tendency of the test results is the same as that of the needle valve.

  DESCRIPTION OF SYMBOLS 1 ... Hard-coat layer, 2 ... Antireflection layer, 3 ... Antireflection film, 5 ... Curing apparatus, 10 ... Ultraviolet irradiation apparatus, 12 ... Web, 14 ... Support roller, 16 ... Ultraviolet lamp house, 16A ... Irradiation surface, 18 DESCRIPTION OF SYMBOLS ... UV irradiation space, 20 ... Overhang member, 20E, 20F ... Supply port of mixed gas, 22 ... Mixed gas supply device, 24 ... Air-conditioning clean room, 26 ... Power room, 28 ... Nitrogen gas line, 30 ... Compressed air line, 32 ... Nitrogen piping, 32A ... First nitrogen piping, 32B ... Second nitrogen piping, 34 ... Nitrogen cylinder, 36 ... Open / close valve, 38 ... Pressure gauge, 40 ... Pressure adjustment valve, 42A, 42B ... Flow rate adjustment valve (disc valve) ), 44A, 44B ... flow meter, 46 ... compressed air piping, 46A ... first compressed air piping, 46B ... second compressed air piping, 48 ... compressor, 50 ... open / close valve, 52 ... pressure gauge, 54 Pressure regulating valve, 56A, 58A, 60A (56B, 58B, 60B) ... 1st to 3rd flow regulating valve (needle valve), 62A, 62B ... flow meter, 68 ... valve product temperature maintaining means, 70A ... heater, 70 ... Insulating casing, 72 ... Temperature sensor, 74 ... Temperature control means

Claims (9)

In the curing method of the coating layer in which the photocurable coating layer formed on the belt-shaped support to be conveyed is cured by irradiating with ultraviolet rays from the irradiation surface of the ultraviolet irradiation device,
In the ultraviolet irradiation space between the irradiation surface and the coating layer, an oxygen-containing gas and an inert gas are merged from the respective pipes to obtain a target oxygen concentration in an oxygen concentration region of 0.1% to 10.0%. A mixed gas supply step for supplying a mixed gas mixture;
In the mixed gas supply step,
A plurality of valves having different nominal diameters are provided in series or in parallel in the piping of the oxygen-containing gas,
By adjusting the flow rate of the oxygen-containing gas to be mixed among the plurality of valves according to the level of the target oxygen concentration in the oxygen concentration region, in all regions of the oxygen concentration region , Adjusting the mixed gas to within ± 5% of the target oxygen concentration ,
Wherein the plurality of valves needle valve der Ru method of curing the coating layer.   A valve having a smaller nominal diameter is selected from among the plurality of valves as the target oxygen concentration in the oxygen concentration region is lower, and a valve having a larger nominal diameter is selected from the plurality of valves as the target oxygen concentration is higher. The method for curing a coating layer according to claim 1.   The method for curing a coating layer according to claim 1, wherein the selected valves are a plurality of valves having different nominal diameters. Measure the oxygen concentration of the supplied mixed gas,
A feedback control is performed on the degree of opening of the plurality of valves so that the measured value transitions within the target oxygen concentration ± 5% by comparing the measured value with the target oxygen concentration. Item 4. The method for curing a coating layer according to any one of Items 1 to 3 . Together with the plurality of valves are arranged in series on the pipe, according to claims 1 to disposed upstream of smaller nominal diameter of the valve a valve larger nominal diameter to any one of the fourth coating layer Curing method. An ultraviolet irradiation device that cures the photocurable coating layer formed on the belt-shaped support to be conveyed by irradiating ultraviolet rays, and oxygen in an ultraviolet irradiation space between the irradiation surface of the ultraviolet irradiation device and the coating layer In a coating layer curing device comprising: a mixed gas supply device that supplies a mixed gas of a contained gas and an inert gas;
The piping of the oxygen-containing gas of the mixed gas supply device is provided with a plurality of valves having different nominal diameters in series or in parallel as flow rate adjusting valves ,
Wherein the plurality of valves curing apparatus Ru needle valve der coating layer. An oxygen concentration meter for measuring the oxygen concentration of the supplied mixed gas;
Feedback control for controlling the opening of the valve in use among the plurality of valves such that said measured value by comparing said measured value with objectives oxygen concentration measured is to remain at the target oxygen concentration within ± 5% And a coating layer curing device according to claim 6 . 8. The coating layer curing device according to claim 6, wherein the plurality of valves are arranged in series with the pipe, and a valve having a large nominal diameter is arranged upstream of a valve having a small nominal diameter. A curing step of curing the photocurable coating layer by irradiating the photocurable coating layer coated on the transported belt-shaped support with ultraviolet rays from the irradiation surface of the ultraviolet irradiation device, and light after curing In a method for producing a laminated film comprising at least a laminating step of coating and laminating another coating layer on a curable coating layer,
In the curing step, an oxygen-containing gas and an inert gas are merged from each pipe into an ultraviolet irradiation space between the irradiation surface and the coating layer, and an oxygen concentration region of 0.1% to 10.0%. A mixed gas supply step of supplying a mixed gas mixed with the target oxygen concentration of
In the mixed gas supply step,
A plurality of valves having different nominal diameters are provided in series or in parallel in the piping of the oxygen-containing gas,
By adjusting the flow rate of the oxygen-containing gas to be mixed among the plurality of valves according to the level of the target oxygen concentration in the oxygen concentration region, in all regions of the oxygen concentration region , Adjusting the mixed gas to within ± 5% of the target oxygen concentration ,
Wherein the plurality of valves method for producing a laminated film Ru der needle valve.

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