Needle valve and method for manufacturing the same

Abstract

To provide a needle valve that reduces generation of particles, and a manufacturing method.SOLUTION: A needle valve 1 includes: a diaphragm 3 including a needle part 3a and a deformable membrane part 3b extending outwards therefrom; and a body 5 in which a valve chamber 6 is formed and which includes a cylindrical flow path part 5a that opens to the valve chamber. The opening area of the flow path part can be adjusted by a reciprocating movement of the needle part in the direction of a movement axis C. Each of the needle part and the flow path part is such that a tertiary carbon concentration M1 (mol%) at one end in each axial direction and a tertiary carbon concentration M2 (mol%) at the other end satisfy M1≥0.01, M2≥0.01, and 0.8≤M1 / M2≤1.2. A manufacturing method includes: a step of obtaining a cut piece of a cross-linked PFA film cross-linked such that a tertiary carbon concentration is greater than or equal to 0.01 mol%; a step of obtaining a re-molded object by re-molding the cut piece; and a step of obtaining a needle part and a flow path part from the re-molded object.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a needle valve and a manufacturing method thereof, and more particularly to a needle valve equipped with a diaphragm used for fluid control and a manufacturing method thereof. [Background technology]

[0002] Needle valves can be used to control various fluids in various situations, for example, to control the flow and flow rate of chemicals used in semiconductor manufacturing. In this case, the needle valve has a body and a diaphragm made of fluororesin such as polytetrafluoroethylene (PTFE) or perfluoroalkoxyalkane (PFA) because of its excellent chemical resistance and bending durability. The body has a valve chamber connected to a plurality of flow paths, and the diaphragm is allowed to reciprocate in the direction of the movement axis within the valve chamber. Therefore, the size of the gap between the needle portion located at the lower end of the diaphragm and the flow path portion is changed, thereby realizing a change in the flow rate.

[0003] In such a needle valve, it is necessary to prevent particle generation due to contact between the needle part and the flow path part. Particles are fine particles of the material that constitutes the needle valve. The needle part and the flow path part are not necessarily designed to contact each other, but are designed to have a small gap between them for the purpose of flow control. Therefore, the smaller the gap, the higher the probability of contact between the two due to variations during assembly and variations due to dimensional tolerances of parts. Since the needle part and the flow path part are in a liquid contact area, if particles are generated at these points, they may be mixed into the chemical liquid that is circulating. If the above-mentioned chemical liquid is, for example, a cleaning liquid used in semiconductor manufacturing, the cleaning liquid containing particles will circulate, which causes a problem of reduced cleanliness due to cleaning. To address this problem, the technology of Patent Document 1 below is known. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-095226 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned Patent Document 1 discloses a flow control valve having a degree of freedom that allows the rod to tilt around the elastic body as a fulcrum, and is provided with an annular elastic body on the outer peripheral surface of a rod linked to the needle valve body, in order to suppress the occurrence of wear even when the needle valve body hits the annular valve seat on one side. According to this configuration, when the needle valve body hits the annular valve seat on one side, the rod tilts, and the contact pressure applied to the needle valve body is alleviated to suppress wear. However, the degree of freedom cannot be increased without limit, and the temperature of the chemical solution may be as high as about 200°C. Considering the dimensional changes such as expansion and contraction caused by temperature changes, it is not considered that wear resistance can be sufficiently achieved by the degree of freedom alone. In addition, Patent Document 1 describes that the needle valve body and the annular valve seat are made of fluororesin (e.g., PFA or PTFE) (

[0040] ,

[0024] ), but does not describe or suggest cross-linked fluororesin.

[0006] The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a needle valve capable of suppressing generation of particles, and a manufacturing method thereof. [Means for solving the problem]

[0007] That is, the present invention includes the following. [1] A needle valve comprising: a diaphragm having a needle portion and a membrane portion extending outward from the needle portion and deformable in a direction of a movement axis; and a body having a valve chamber formed therein and a cylindrical flow path portion opening into the valve chamber, wherein the flow path portion has an axis coincident with that of the needle portion, and the opening area of ​​the flow path portion can be adjusted by reciprocating movement of the needle portion in the direction of the movement axis due to deformation of the membrane portion, The needle valve is characterized in that, when a tertiary carbon concentration at one end in each axial direction is M1 (mol %) and a tertiary carbon concentration at the other end in each axial direction is M2 (mol %), each of the needle portion and the flow path portion satisfies M1≧0.01, M2≧0.01, and 0.8≦M1 / M2≦1.2. [2] The diaphragm comprises a base made of a non-crosslinked fluororesin; The needle valve according to the above-mentioned [1], which is integrated with the base portion, has the needle portion, and has an end portion made of the cross-linked PFA. [3] The body includes a base portion made of a non-crosslinked fluororesin; The needle valve according to [1] or [2] above, which is integrated with the base, has the flow path portion, and has an end portion made of the cross-linked PFA. [4] The needle valve according to any one of [1] to [3] above, wherein the distance between the one end and the other end is 250 μm or more. [5] A needle valve described in any one of [1] to [4] above, wherein the needle portion and the flow path portion are made of remolded pieces of a cross-linked PFA film that has been cross-linked so that the tertiary carbon concentration is 0.01 mol % or more. [6] The needle valve described in [2] above, wherein the diaphragm and the body are cut from a composite body formed by integrating an intermediate material made of non-crosslinked fluororesin as the base and a remolded piece of crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol % or more. [7] A method for manufacturing a needle valve according to any one of [1] to [6] above, A cutting step of obtaining cut pieces of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more; a remolding step of remolding the cut pieces to obtain a remolded product; and obtaining the needle portion and the flow path portion from the remolded product. [8] A method for producing a needle valve as described in [7] above, comprising an integration step of obtaining a composite material by integrating an intermediate material made of a non-crosslinked fluororesin with the remolded product. [9] The integration step includes a cut piece receiving step of receiving the cut piece in a cavity provided in the intermediate material; and a firing step of melting the cut piece in the cavity to obtain the remolded product and integrating the intermediate material with the remolded product.

[10] The method for manufacturing a needle valve described in [8] or [9] above, wherein the integration process includes an injection process of injecting a molten material of the cut piece into a cavity formed in the intermediate material to obtain the remolded product within the cavity and integrate the intermediate material with the remolded product.

[11] The integrating step includes a cut piece receiving step of receiving the cut piece in a cavity provided in the intermediate material; a compression molding step of compressing the cut piece in the cavity to obtain the remolded product and integrating the intermediate material with the remolded product.

[12] A method for producing a needle valve as described in [7] above, comprising a welding step of obtaining a composite material by welding an intermediate material made of a non-crosslinked fluororesin and the remolded product obtained in advance. Effect of the Invention

[0008] According to the needle valve of the present invention, generation of particles can be suppressed.

[0009] That is, in a needle valve in which the tertiary carbon concentration M1 (mol %) at one end in the axial direction of the needle part and the tertiary carbon concentration M2 (mol %) at the other end in the axial direction of the flow passage part satisfy M1≧0.01, M2≧0.01, and 0.8≦M1 / M2≦1.2, the needle part from one end to the other in the axial direction and the flow passage part from one end to the other in the axial direction are formed of sufficiently cross-linked cross-linked PFA, so that generation of particles from these locations can be suppressed. Therefore, compared with a needle valve that does not satisfy the above relationship between M1 and M2, the needle valve of the present invention can suppress generation of particles.

[0010] In the above needle valve, the diaphragm can have a base made of a non-crosslinked fluororesin and an end portion made of crosslinked PFA, which is integrated with the base and has a needle portion. In this case, since a non-crosslinked fluororesin having better bending durability than crosslinked PFA can be used as the base, the bending durability of the membrane portion of the diaphragm can be particularly improved. In addition, since it is not necessary to form the entire diaphragm from crosslinked PFA, the manufacturing cost of the needle valve can be reduced.

[0011] In the above needle valve, the body can have a base made of a non-crosslinked fluororesin and an end portion made of crosslinked PFA, which is integrated with the base and has a flow path. In this case, since a non-crosslinked fluororesin having better bending durability than crosslinked PFA can be used as the base, the bending durability of the membrane portion of the diaphragm can be particularly improved. In addition, since it is not necessary to form the entire body from crosslinked PFA, the manufacturing cost of the needle valve can be reduced.

[0012] In the above needle valve, the distance between one end and the other end can be 250 μm or more. Normally, it is difficult to crosslink a thick non-crosslinked PFA from the viewpoint of radiation transmittance, but this can be achieved by the manufacturing method of the needle valve described later. By providing a needle part and a flow path part with the distance of 250 μm or more, wear of the needle part and the flow path part can be suppressed compared to the case where the distance is less than 250 μm, and therefore accurate flow control can be performed for a longer period of time.

[0013] In the above-mentioned needle valve, the needle part and the flow path part can be made of a remolded piece of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more. That is, it is difficult to crosslink a thick non-crosslinked PFA film so that the tertiary carbon concentration is 0.01 mol% or more over the entire front and back from the viewpoint of radiation transmittance, but it is possible to obtain a crosslinked PFA film with a tertiary carbon concentration of 0.01 mol% or more over the entire front and back by irradiating a non-crosslinked PFA film having a thickness that allows this to be done. In addition, if the member is made of crosslinked PFA remolded from the cut piece obtained by cutting this crosslinked PFA film, it can be a crosslinked PFA member that is uniformly crosslinked throughout, regardless of its thickness. By forming the needle part and the flow path part from such a crosslinked PFA member with a uniform degree of crosslinking throughout, it is possible to significantly suppress the generation of particles due to contact between the needle part and the flow path part.

[0014] In the above needle valve, the diaphragm and the body can be cut from a composite material that is an integrated combination of an intermediate material made of a non-crosslinked fluororesin as a base and a remolded cut piece of a crosslinked PFA film that has been crosslinked to have a tertiary carbon concentration of 0.01 mol% or more. In this case, a non-crosslinked fluororesin that has better flexural durability than crosslinked PFA can be used as the base, so that the membrane portion of the diaphragm in particular can have excellent flexural durability. In addition, since it is not necessary to form the entire diaphragm or body from crosslinked PFA, the manufacturing cost of the needle valve can be reduced.

[0015] According to the method for producing a needle valve of the present invention, it is possible to produce a needle valve capable of suppressing generation of particles.

[0016] That is, when the method includes a cutting step of obtaining a cut piece of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more, a remolding step of remolding the cut piece to obtain a remolded product, and a forming step of obtaining a needle part and a flow path part from the remolded product, a crosslinked PFA film that is uniformly crosslinked so that the tertiary carbon concentration is 0.01 mol% or more can be obtained. Then, by remolding the cut piece of the uniformly crosslinked crosslinked PFA film, a remolded product (crosslinked PFA member) made of crosslinked PFA that is uniformly crosslinked so that the entire product has a tertiary carbon concentration of 0.01 mol% or more can be obtained. By forming the needle part and the flow path part from such a crosslinked PFA member that has a uniform degree of crosslinking throughout, the generation of particles due to contact between the needle part and the flow path part can be significantly suppressed.

[0017] The manufacturing method of the needle valve may include an integration step of obtaining a composite material by integrating an intermediate material made of a non-crosslinked fluororesin and a remolded product. In this case, since a non-crosslinked fluororesin having better flexural durability than crosslinked PFA can be used, the membrane part of the diaphragm can be formed by the intermediate material part of the composite material, and the membrane part can have excellent flexural durability. In addition, since it is not necessary to form the entire diaphragm or the body from crosslinked PFA, the manufacturing cost of the needle valve can be reduced. In the manufacturing method of the needle valve, the integration step may include a cut piece accommodation step of accommodating the cut pieces in a cavity provided in the intermediate material, and a firing step of melting the cut pieces in the cavity to obtain a remolded product and integrating the intermediate material and the remolded product. In addition, in the manufacturing method of the needle valve, the integration step may include an injection step of injecting the melted cut pieces into a cavity provided in the intermediate material to obtain a remolded product in the cavity and integrating the intermediate material and the remolded product. In addition, in the manufacturing method of the needle valve, the integration step can include a cut piece accommodation step of accommodating the cut pieces in a cavity provided in the intermediate material, and a compression molding step of compressing the cut pieces in the cavity to obtain a remolded product and integrating the intermediate material and the remolded product. In addition, in the manufacturing method of the needle valve, the integration step can include a cut piece accommodation step of accommodating the cut pieces in a cavity provided in the intermediate material, and a compression molding step of compressing the cut pieces in the cavity to obtain a remolded product and integrating the intermediate material and the remolded product. In addition, the manufacturing method of the needle valve can include a welding step of obtaining a composite material by welding the intermediate material made of a non-crosslinked fluororesin and the previously obtained remolded product. By including these steps, a composite material can be obtained by integrating the intermediate material made of a non-crosslinked fluororesin and the remolded product, so that a diaphragm can be obtained that has a needle part and a flow path part entirely formed from a uniformly crosslinked crosslinked PFA, as described above, and also has a membrane part with excellent bending durability. Furthermore, since the diaphragm or the body does not need to be entirely made from cross-linked PFA, the manufacturing costs of the needle valve can be reduced. [Brief description of the drawings]

[0018] The present invention will be further described in the following detailed description by way of non-limiting examples of exemplary embodiments according to the invention and with reference to the several drawings mentioned, in which like reference numerals refer to like parts throughout the several views of the drawings.

[0019] [Figure 1] FIG. 2 is a vertical cross-sectional view of the needle valve of the embodiment. [Diagram 2] FIG. 4 is a vertical cross-sectional view of a diaphragm that constitutes a needle valve. [Diagram 3] FIG. 2 is a vertical cross-sectional view of a body that constitutes a needle valve. [Figure 4] 1A and 1B are diagrams illustrating the operation of a needle valve, in which (a) shows the fully closed state and (b) shows the fully open state. [Diagram 5] FIG. 1 is an explanatory diagram for explaining a method for producing a needle valve, where (a) shows a cross-linked PFA film, (b) shows a cutting process of the cross-linked PFA film, and (c) shows a remolding process of the cut pieces of the cross-linked PFA film. [Figure 6] FIG. 1 is an explanatory diagram for explaining a manufacturing method of a needle valve (a process for integrating an intermediate material and a remolded product), in which (a) shows an oblique view of the intermediate material and the remolded product, and (b) shows a longitudinal cross-sectional view of the remolded product contained in the container portion of the intermediate material. [Figure 7] 1A and 1B are explanatory diagrams for explaining a manufacturing method of a needle valve (a process for forming a needle portion), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a diaphragm obtained by cutting the composite material. [Figure 8] 1A and 1B are explanatory diagrams for explaining a manufacturing method for another type of needle valve (a step of forming a needle portion), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a diaphragm obtained by cutting the composite material. [Figure 9] 11A and 11B are explanatory diagrams for explaining a manufacturing method for a needle valve of still another embodiment (a step of forming a needle portion), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a diaphragm obtained by cutting the composite material. [Figure 10] FIG. 1 is an explanatory diagram for explaining a manufacturing method of a needle valve (a process for integrating an intermediate material and a remolded product), in which (a) shows an oblique view of the intermediate material and the remolded product, and (b) shows a longitudinal cross-sectional view of the remolded product contained in the container portion of the intermediate material. [Figure 11] 1A and 1B are explanatory diagrams for explaining a manufacturing method of a needle valve (a process for forming a flow path portion), in which (a) shows a longitudinal cross-sectional view of a composite material, and (b) shows a longitudinal cross-sectional view of a body obtained by cutting the composite material. [Figure 12] FIG. 11 is an explanatory diagram for explaining a manufacturing method of a needle valve of another embodiment (a process of integrating an intermediate material and a remolded product). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The matters shown herein are illustrative and are intended to exemplify the embodiments of the present invention, and are described for the purpose of providing what is believed to be the most effective and easily understandable explanation of the principles and conceptual features of the present invention. In this respect, it is not intended to show structural details of the present invention beyond the extent necessary for a fundamental understanding of the present invention, and the description in conjunction with the drawings will make it clear to those skilled in the art how some forms of the present invention can be actually embodied.

[0021] The present invention will now be described in detail with reference to the accompanying drawings.

[0022] 1, the needle valve 1 of this embodiment includes a diaphragm 3 having a needle portion 3a and a membrane portion 3b extending outward from the needle portion 3a and deformable in the direction of the movement axis C, and a body 5 in which a valve chamber 6 is formed and which has a cylindrical flow path portion 5a that opens into the valve chamber 6. In the needle valve 1, the flow path portion 5a is aligned with the needle portion 3a, and the needle portion 3a is moved back and forth in the direction of the movement axis C due to deformation of the membrane portion 3b, thereby making it possible to adjust the opening area of ​​the flow path portion 5a. In addition, the needle valve 1 includes a drive portion 15 that drives the diaphragm 3.

[0023] The diaphragm 3 is disposed so as to close the upper opening of the valve chamber 6, and is fixed to the body 5. The diaphragm 3 has a needle portion 3a disposed in the center, an annular membrane portion 3b formed thin so as to be easily bent and supporting the needle portion 3a, and an outer peripheral edge portion 3c disposed on the outer peripheral side of the membrane portion 3b (see FIG. 2). The diaphragm 3 has a valve body portion 3d disposed so as to surround the needle portion 3a. The diaphragm 3 further has a connection portion 3e disposed above the needle portion 3a and connected to a stem 16 of the drive portion 15. The diaphragm 3 partitions the valve chamber 6 and the drive portion 15 while supporting the needle portion 3a and the valve body portion 3d in the valve chamber 11 via the membrane portion 3b.

[0024] The needle portion 3a protrudes toward the flow passage portion 5a beyond the tip of the valve body portion 3d (specifically, the tip of the rib 4). The needle portion 3a has a tapered shape that tapers toward the flow passage portion 5a. The shape of the flow passage portion 5a (flow passage defined by the inner circumference of the flow passage portion 5a) in a cross section (transverse section) perpendicular to the axial direction and the shape of the needle portion 3a in the same transverse section are made to correspond to each other (for example, both are circular, etc.). Furthermore, each portion is formed and assembled so that the center of the flow passage portion 5a in the same transverse section approximately coincides with the center of the needle portion 3a in the same transverse section. Therefore, by adjusting the insertion position of the needle portion 3a with respect to the flow passage portion 5a, the size of the flow passage defined by the inner peripheral surface of the flow passage portion 5a and the outer peripheral surface of the needle portion 3a is adjusted, and the flow rate of the flow passage portion 5a is adjusted.

[0025] The membrane portion 3b is provided so as to expand radially outward from the needle portion 3a. More specifically, it is formed so as to extend radially outward from the outer periphery of the lower end of the connection portion 3e. The outer periphery of the membrane portion 3b has a roughly circular shape. The outer periphery edge portion 3c has an L-shaped cross section. At least a part of the outer periphery edge portion 3c is sandwiched between the body 5 and the pressing member 21. The valve body portion 3d is provided with an annular rib 4 protruding toward the flow path portion 5a. The rib 4 is pressed against the valve seat surface 5b to fully close the flow path of the flow path portion 5a. The outer periphery of the connection portion 3e and the inner periphery of the lower end of the stem 16 are formed with threaded portions 26 that mesh with each other. The diaphragm 3 and the stem 16 are connected via the connection portion 3e, and the insertion position of the needle portion 3a relative to the flow path portion 5a is adjusted by raising and lowering the diaphragm 3 via the stem 16 by the drive portion 15.

[0026] In this embodiment, the diaphragm 3 is provided with the valve body portion 3d, but the present invention is not limited to this, and a configuration without the valve body portion 3d (see FIG. 9) may be adopted. In this case, for example, a stopper portion that engages with the stem 16 can be provided on the drive unit housing 17 side, etc., to regulate the lowering end position of the needle portion 3a of the diaphragm 3.

[0027] As shown in Fig. 2, the diaphragm 3 has a base 33a made of a non-crosslinked fluororesin, and an end 33b made of crosslinked PFA, which is integrated with the base 33a and has a needle portion 3a. That is, the base 33a including the membrane portion 3b is made of a non-crosslinked fluororesin which is cheaper than crosslinked PFA and has high bending durability. The end 33b including the needle portion 3a is made of crosslinked PFA which has high abrasion resistance and strength. Furthermore, the diaphragm 3 is cut from a composite material 45 which integrates an intermediate material 44 made of a non-crosslinked fluororesin which becomes the base 33a, and a remolded product 43 (remolded product 43 which becomes the end 33b) of a cut piece 42 of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more (see Figs. 7 to 9).

[0028] The type of fluororesin constituting the non-crosslinked fluororesin is not limited, and a polymer (homopolymer or copolymer) using a fluorine-substituted polymerizable compound as a monomer, such as tetrafluoroethylene [F2C=CF2], hexafluoropropene [F2C=CF2-CF3], difluoroethylene [H2C=CF2], chlorotrifluoroethylene [F2C=CFCl], perfluoroalkoxyethylene (perfluoromethoxyethylene [F2C=CF-O-CF3], perfluoroethoxyethylene [F2C=CF-O-CF2-CF2], etc.), can be used. Among these, ethylene (non-fluorine-substituted ethylene) can be used as a copolymer monomer. Specifically, for example, PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane, tetrafluoroethylene-perfluoroalkoxyethylene copolymer resin), FEP (tetrafluoroethylene-hexafluoropropene copolymer resin), ETFE (ethylene-tetrafluoroethylene copolymer resin), PVDF (polyvinylidene fluoride, difluoroethylene polymer), PCTFE (polychlorotrifluoroethylene), ECTFE (ethylene-chlorotrifluoroethylene copolymer resin), etc. can be used. These may be used alone or in combination of two or more. Among these, non-crosslinked PTFE is preferable as the base 33a from the viewpoints of suppressing melting due to heating, maintaining the shape by gelation, and reducing material costs.

[0029] Moreover, crosslinking in fluororesin means that different polymer molecules constituting the fluororesin form carbon-carbon bonds. Therefore, non-crosslinked PFA usually does not have tertiary carbon, but crosslinked PFA does. Therefore, the presence or absence of tertiary carbon corresponds to the presence or absence of crosslinking in PFA, and it can be seen that the higher the tertiary carbon concentration, the more crosslinks there are in PFA. In the present invention, crosslinking is considered to occur when the tertiary carbon concentration is 0.01 mol% or more. The upper limit of this tertiary carbon concentration is not limited, but is usually 0.7 mol% or less. By maintaining the tertiary carbon concentration at 0.7 mol% or less, the mechanical strength of the crosslinked PFA can be maintained high.

[0030] Tertiary carbon concentration of cross-linked PFA 19 F-NMR measurement (measurement device: solid 19 The integral values ​​of the peaks A to G shown in Table 1 below are measured by F-NMR (Bruker Biospin AVANCE III-400WB, measurement conditions: 376 MHz, rotation speed 27 kHz), and then calculated (based on peak C) using the following calculation formula (1). The presence of tertiary carbon can be ascertained from the presence of peak C and / or peak G, but as described above, the tertiary carbon concentration is basically calculated according to formula (1) using the peak intensity of peak C. However, when peak C is not detected and only peak G is detected, the tertiary carbon concentration is calculated using formula (2) below. This is because the tertiary carbon concentration calculated by formula (1) and the tertiary carbon concentration calculated by formula (2) are usually substantially the same value.

[0031] In addition, the following formula [I A / 3 ], [I B / 5 ], [I C / 6 ], [I D / 4 ], [I E / 2 ], [I F / 1 ] and [I G / 1 ] are as follows: [I A / 3 ]: Equivalent F in the structure of "A" in Table 1 * Since there are three peaks, the peak intensity based on "A" is "I A ", then one F in "A" * The peak intensity for I A / 3" and this value is [I A / 3 ] should be written. [I B / 5 ]: Equivalent F in the structure of "B" in Table 1 * Since there are five, the peak intensity based on "B" is "I B ", then one F in "B" * The peak intensity for I B / 5" and this value is [I B / 5 ] should be written. [I C / 6 ]: Equivalent F in the structure of "C" in Table 1 * Since there are six peaks, the peak intensity based on "C" is "I C ", then one F in "C" * The peak intensity for I C / 6" and this value is [I C / 6 ] should be written. [I D / 4 ]: Equivalent F in the structure of "D" in Table 1 * Since there are four, the peak intensity based on "D" is "I D ", then one F in "D" * The peak intensity for I D / 4" and this value is [I D / 4 ] should be written. [I E / 2 ]: Equivalent F in the structure of "E" in Table 1 * Since there are two, the peak intensity based on "E" is "I E ", then one F in "E" * The peak intensity for I E / 2" and this value is [I E / 2 ] should be written. [I F / 1 ]: Equivalent F in the structure of "F" in Table 1 * Since there is only one, the peak intensity based on "F" is "I F ", then one F in "F" * The peak intensity for I F / 1" and this value is [I F / 1 ] should be written. [I G / 1 ]: Equivalent F in the structure of "G" in Table 1 * Since there is only one, the peak intensity based on "G" is "I G ", then one F in "G" * The peak intensity for I G / 1" and this value is [I G / 1 ] should be written.

[0032] [Formula (1)]I C / 6 Tertiary carbon concentration based on Tertiary carbon concentration (mol%) = [I C / 6 ] / {[I A / 3 ]+[I B / 5 ]+[I D / 4 ]+[I E / 2 ]+[I F / 1 ]+[I G / 1 ]}×100 [Formula (2)]I G / 1 Tertiary carbon concentration based on Tertiary carbon concentration (mol%) = {[I G / 1 ]-[I A / 3 ]} / {[I B / 5 ]+[I C / 6 ]+[I D / 4 ]+[I E / 2 ]+[I F / 1 ]}×100

[0033] [Table 1]

[0034] The needle portion 3a is made of cross-linked PFA from one end to the other end, and satisfies M1>0.01, M2>0.01, and 0.8≦M1 / M2≦1.2, where M1 (mol%) is the tertiary carbon concentration at one end and M2 (mol%) is the tertiary carbon concentration at the other end. That is, the needle portion 3a has a tertiary carbon concentration M1 at one end that exceeds 0.01 mol%, and at the same time, the tertiary carbon concentration M2 at the other end also exceeds 0.01 mol%. In addition, the ratio (M1 / M2) of M1 to M2 is 0.8 or more and 1.2 or less, and M1 and M2 are close to each other. Therefore, the needle portion 3a is made of cross-linked PFA that is uniformly cross-linked from one end to the other end. The needle portion 3a has a distance D1 between one end and the other end of about 250 to 6000 μm (see FIG. 2), which is 250 μm or more. The needle portion 3a is a portion of the end portion 33b that can be inserted into the flow path portion 5a and has a tapered shape at a certain angle (see FIG. 2).

[0035] The needle portion 3a made of cross-linked PFA that is uniformly cross-linked from one end to the other may be formed in any manner, but can be formed from a remolded product 43 of a cut piece 42 of a cross-linked PFA film 41 that has been cross-linked so that the tertiary carbon concentration is 0.01 mol % or more (see Figure 5). That is, for example, in the case of a thin film-like non-crosslinked PFA of less than 250 μm, radiation can be irradiated so as to reach both sides of the film. On the other hand, for example, in the case of a thick film-like non-crosslinked PFA of 250 μm or more, it becomes difficult to transmit radiation, and a crosslinked PFA film with different degrees of crosslinking on the front and back is formed. In addition, the output of radiation can be increased to transmit the front and back of the non-crosslinked PFA film, but as a result, the degree of crosslinking on the front and back may differ due to attenuation during transmission, and the use of high-output radiation leads to a rapid increase in costs, making it difficult to adopt. Therefore, in order to obtain a crosslinked PFA that is low-cost and has a high degree of freedom in shape while reliably crosslinking, radiation is irradiated to a thin film-like non-crosslinked PFA of less than 250 μm so as to reach both sides of the film, the film is uniformly crosslinked, and then the cut pieces 42 obtained by cutting the film are remolded, whereby a crosslinked PFA having a desired shape that is uniformly crosslinked can be obtained. Furthermore, for example, among fluororesins, PTFE is difficult to melt-form, regardless of whether it is crosslinked or not. On the other hand, since PFA can be melt-molded even after crosslinking, it is possible to obtain a block of crosslinked PFA 43 from cut piece 42 of crosslinked PFA film 41 by remolding.

[0036] The body 5 is formed with a valve chamber 6 at the center of the upper part, and with a first flow passage and a second flow passage communicating with the valve chamber 6. The body 5 is also formed with a flow passage portion 5a where the needle portion 3a faces the opening from the first flow passage to the valve chamber 6. The upper end surface of the flow passage portion 5a of the body 5 constitutes a valve seat surface 5b with which the rib 4 of the valve body portion 3d comes into contact (see Figs. 2 and 3). In this embodiment, the first flow passage is formed with an inlet flow passage 8 that extends from an inlet port 7 formed on one of the opposing side surfaces of the body 5 and opens at the center of the bottom of the valve chamber 6. The valve seat surface 5b is formed around the opening from the inlet flow passage 8 to the valve chamber 6. The second flow passage is formed with an outlet flow passage 10 that extends from an outlet port 9 formed on the other opposing side surface of the body 5 and opens to the outside of the bottom of the valve chamber 6. The outlet flow passage 10 opens to the outside of the bottom of the valve chamber 6 and is formed so as to be at the same height as the inlet flow passage 8.

[0037] The upper part of the body 5 is provided with a recess 12 for receiving the fitting part 21b of the pressing member 21. A drive unit housing 17 is disposed above the body 5, and a base plate 13 is disposed below the body 5. The drive unit housing 17 has a hollow cylindrical shape, and the base plate 13 has a flange shape. The drive unit housing 17, the body 5, and the base plate 13 are integrally fastened with bolts and nuts (not shown). The body 5 is sandwiched and fixed between the drive unit housing 17 and the base plate 13.

[0038] The body 5 has a base 35a made of a non-crosslinked fluororesin, and an end 35b made of crosslinked PFA, which is integrated with the base 35a and has a flow path 5a (see FIG. 11). That is, the base 35a (specifically, a portion of the body 5 having a larger volume than the end 35b) is made of a non-crosslinked fluororesin that is less expensive than crosslinked PFA. The end 35b, which includes the flow path 5a, is made of crosslinked PFA, which has high abrasion resistance and strength. Furthermore, the body 5 is cut from a composite material 45 that integrates an intermediate material 44 made of a non-crosslinked fluororesin that becomes the base 35a, and a remolded product 43 (i.e., the remolded product 43 that becomes the end 35b) of a cut piece 42 of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more (see FIG. 5, FIG. 10, and FIG. 11).

[0039] The type of fluororesin constituting the non-crosslinked fluororesin is not limited, and as described above in the description of the diaphragm 3, a polymer (homopolymer or copolymer) using a fluorine-substituted polymerizable compound such as tetrafluoroethylene, hexafluoropropene, difluoroethylene, chlorotrifluoroethylene, perfluoroalkoxyethylene (perfluoromethoxyethylene, perfluoroethoxyethylene) as a monomer can be used. Of these, ethylene (non-fluorine-substituted ethylene) can be used as a monomer for the copolymer. Specifically, for example, PTFE, PFA, FEP, ETFE, PVDF, PCTFE, ECTFE, etc. can be used. These may be used alone or in combination of two or more. Of these, non-crosslinked PTFE is preferable as the base 35a from the viewpoints of suppressing melting due to heating and maintaining the shape by gelation, and of reducing material costs. Moreover, the cross-linking in the fluororesin is also as described above in the explanation of the diaphragm 3.

[0040] When the tertiary carbon concentration at one end in the axial direction is M1 (mol%) and the tertiary carbon concentration at the other end in the axial direction is M2 (mol%), the flow path portion 5a satisfies M1>0.01, M2>0.01, and 0.8≦M1 / M2≦1.2. Therefore, the flow path portion 5a is formed of crosslinked PFA that is uniformly crosslinked along the axial direction, and has high wear resistance and strength. Furthermore, the flow path portion 5a is formed of a remolded product 43 of a cut piece 42 of a crosslinked PFA film that is crosslinked so that the tertiary carbon concentration is 0.01 mol% or more. The flow path portion 5a has a distance D2 between one end and the other end of about 250 to 6000 μm (see FIG. 2), which is 250 μm or more. The thickness D3 of the flow path portion 5a is also about 250 to 12000 μm (see FIG. 2), which is 250 μm or more.

[0041] The flow path section 5a made of cross-linked PFA that is uniformly cross-linked from one end to the other may be formed in any manner, but can be formed from a remolded product 43 of a cut piece 42 of a cross-linked PFA film 41 that has been cross-linked so that the tertiary carbon concentration is 0.01 mol % or more (see Figure 5). That is, for example, in the case of a thin film-like non-crosslinked PFA of less than 250 μm, radiation can be irradiated so as to reach both sides of the film. On the other hand, for example, in the case of a thick film-like non-crosslinked PFA of 250 μm or more, it becomes difficult to transmit radiation, and a crosslinked PFA film with different degrees of crosslinking on the front and back is formed. In addition, the output of radiation can be increased to transmit the front and back of the non-crosslinked PFA film, but as a result, the degree of crosslinking on the front and back may differ due to attenuation during transmission, and the use of high-output radiation leads to a rapid increase in costs, making it difficult to adopt. Therefore, in order to obtain a crosslinked PFA that is low-cost and has a high degree of freedom in shape while reliably crosslinking, radiation is irradiated to a thin film-like non-crosslinked PFA of less than 250 μm so as to reach both sides of the film, the film is uniformly crosslinked, and then the cut pieces 42 obtained by cutting the film are remolded, whereby a crosslinked PFA having a desired shape that is uniformly crosslinked can be obtained. Furthermore, for example, among fluororesins, PTFE is difficult to melt-form, regardless of whether it is crosslinked or not. On the other hand, since PFA can be melt-molded even after crosslinking, it is possible to obtain a block of crosslinked PFA 43 from cut piece 42 of crosslinked PFA film 41 by remolding.

[0042] The above-mentioned driving unit 15 is manually operated to move the diaphragm 3 forward and backward in the axial direction together with the stem 16 to adjust the position of the needle portion 3a relative to the flow passage portion 5a. The driving unit 15 moves the stem 16 by a screw system that utilizes the meshing of threads. Specifically, the driving unit 15 is composed of a screw portion 27 provided to mesh with the inner peripheral surface of the through hole 24 of the driving unit housing 17 and the outer peripheral surface of the first stem 16a, and a screw portion 28 provided to mesh with the inner peripheral surface of the first stem 16a and the outer peripheral surface of the second stem 16b. However, the driving unit 15 is not limited to a screw system operated manually, and may be, for example, a form in which the diaphragm 3 is driven by using a fluid pressure (such as air pressure) or an electric actuator equipped with a motor, solenoid, or the like.

[0043] The stem 16 is connected to the connection portion 3e of the diaphragm 3 and extends toward the opposite side to the flow passage portion 5a. The stem 16 has a first stem 16a and a second stem 16b connected to the first stem 16a via a screw portion 28. The connection portion 3e of the diaphragm 3 is connected to the lower end of the second stem 16b via a screw portion 26. The first stem 16a is made of PVDF. The first stem 16a has a hollow cylindrical shape with an open lower end. A stopper portion 18 that expands radially outward is provided at the lower end of the first stem 16a. A handle 19 for rotating the first stem 16a is attached to the upper end of the first stem 16a. The second stem 16b is also made of PVDF. The outer periphery of the lower part of the second stem 16b is formed in a hexagonal shape.

[0044] The drive unit housing 17 is made of PVDF. A through hole 24 through which the first stem 16a is inserted is formed at the upper end of the drive unit housing 17. A step portion 17a having a hexagonal inner peripheral surface is provided at the lower part of the drive unit housing 17. The pressing member 21 is made of PVDF. The pressing member 21 has a step portion 21a and a cylindrical fitting portion 21b provided on the lower outer peripheral side of the step portion 21a. The step portion 21a and the fitting portion 21b all have a hexagonal outer peripheral surface. A through hole 22 having a hexagonal inner peripheral surface is formed at the center of the pressing member 21. The lower part of the second stem 16b is inserted into the through hole 22 in a non-rotatable manner. The step portion 21a of the pressing member 21 is non-rotatably fitted into the step portion 17a of the drive unit housing 17. Further, the fitting portion 21b of the pressing member 21 is non-rotatably fitted into the recess 12 of the body 5. As a result, the pressing member 21 supports the second stem 16b so as to be vertically movable and non-rotatable.

[0045] Next, a method for manufacturing the needle valve 1 having the above configuration will be described. First, the intermediate material 44 having a cylindrical cavity 44a is made from a non-crosslinked fluororesin. PTFE can be used as this non-crosslinked fluororesin. In this embodiment, as shown in Fig. 6 (manufacturing the diaphragm 3) and Fig. 10 (manufacturing the body 5), a cup-shaped intermediate material 44 having a recess functioning as a cavity 44a at its upper end is manufactured. The intermediate material 44 may be formed by any method, but may be manufactured, for example, by forming a recess by cutting at the upper end of a rod-shaped body or plate compression-molded from a non-crosslinked fluororesin using a mold by a free baking method, hot molding method, or the like. Similarly, the intermediate material 44 may be manufactured by compression-molding a cup-shaped rod-shaped body or plate having a recess at its upper end from a non-crosslinked fluororesin using a mold by a free baking method, hot molding method, or the like. Moreover, the intermediate material 44 does not need to be integrally formed, and can be produced, for example, by combining a cylindrical tubular body with a solid rod-shaped body or plate-shaped body (including a sheet-shaped body) disposed adjacent to the lower part of the cylindrical tubular body. In this case, the tubular body and the rod-shaped body or plate-shaped body may be joined by screwing or uneven fitting. Furthermore, when the tubular body and the rod-shaped body or plate-shaped body (including a sheet-shaped body) are integrally formed, they may be produced separately and then joined by welding. The welding can be performed, for example, by laser welding, hot plate welding, hot air welding, heating block welding, diffusion bonding, baking, etc. When the intermediate material 44 is produced from a rod-shaped body of non-crosslinked fluororesin, the rod-shaped body of non-crosslinked fluororesin may be produced by extrusion molding.

[0046] On the other hand, a remolded object 43 having a shape and size that can be accommodated in the cavity 44a (recess) of the intermediate material 44 as shown in Figures 6 and 10 is produced from the cross-linked PFA (remolding step). The remolded object 43 may be remolded in a place other than the cavity 44a, or may be remolded inside the cavity 44a. When remolding at a location other than the cavity 44a, a rod-shaped body whose outer peripheral shape is complementary to the inner peripheral surface of the cylindrical cavity 44a can be remolded from the crosslinked PFA in the same manner as the intermediate material 44 described above. In this case, a cut piece 42 of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more can be used as the raw material for the crosslinked PFA. That is, for example, as shown in FIG. 5(a), a crosslinked PFA film 41 can be formed by irradiating a film made of non-crosslinked PFA (non-crosslinked PFA film) with radiation. That is, by irradiating a thin non-crosslinked PFA formed in a film shape with radiation, a crosslinked PFA film that is uniformly crosslinked on both sides can be obtained. More specifically, by irradiating the uncrosslinked PFA film to be irradiated with radiation at an accelerating voltage such that the absorbed dose on the back side of the irradiated surface is 20% or more (preferably 60% or more) of the absorbed dose on the front side relative to the thickness of the uncrosslinked PFA film to be irradiated in a temperature environment above the melting point of the uncrosslinked PFA, a crosslinked PFA film having a tertiary carbon concentration of 0.01 mol % or more across both sides of the film can be obtained.

[0047] Thereafter, as shown in FIG. 5(b), the crosslinked PFA film that has been uniformly crosslinked on both sides is cut to obtain cut pieces 42, thereby obtaining a crosslinked PFA material with a higher degree of freedom in shape. Furthermore, as shown in FIG. 5(c), the cut pieces 42 of the crosslinked PFA film are placed in a cavity of a mold 46 having a predetermined shape, and are then heated and melted, followed by solidification to obtain a remolded product 43. This remolded product 43 can be placed in the cavity 44a of the intermediate material 44 after being shaped by cutting or the like so that it can be placed in the cavity 44a. Also, for example, from the viewpoint of being able to heat and melt it, the height of the remolded product 43 may be approximately equal to the depth of the cavity 44a, or may be shorter than the depth of the cavity 44a, so long as it does not overflow from the cavity 44a when heated and melted. The remolded product 43 can also be directly produced from the crosslinked PFA by extrusion molding or injection molding using a mold, for example.

[0048] On the other hand, when remolding the remolded product 43 inside the cavity 44a, as shown in FIG. 12, the cut pieces 42 of the cross-linked PFA film described above are placed in the cavity 44a (cut piece placement process), and are heated and melted in the cavity 44a to obtain the remolded product 43 made of cross-linked PFA having a shape complementary to the inner surface of the cavity 44a. In this case, only the cut pieces 42 of the crosslinked PFA film housed in the cavities 44a can be heated and melted, but the cavity 44a can also be heated. That is, for example, the entire intermediate material 44 can be heated. This method is preferably used when the intermediate material 44 is made of non-crosslinked PTFE. The non-crosslinked PTFE is gelled and not melted even at a temperature at which the crosslinked PFA is heated and melted. Therefore, the general shapes of the intermediate material 44 and the cavity 44a can be maintained. Then, after the cut pieces 42 of the crosslinked PFA film are heated and melted, they are remolded into a shape corresponding to the cavity 44a, and then cooled and solidified, and at the same time, the cavity 44a is also cooled and solidified, and at that time, the two (the intermediate material 44 and the remolded product 43) are integrated, and a composite material 45 of these is obtained (firing process).

[0049] In this way, when the remolded object 43 is remolded inside the cavity 44a, the production of the remolded object 43 and the integration of the obtained remolded object 43 with the intermediate material 44 can be realized by one heating, melting, cooling and solidification, so that excellent manufacturing efficiency can be achieved. In addition, since a mold for obtaining the remolded object 43 is not required, the needle valve can be manufactured at low cost. Furthermore, when the remolded object 43 is obtained inside the cavity 44a while the entire intermediate material 44 is heated, the occurrence of distortion and residual stress can be suppressed, so that excellent bonding strength can be obtained between the two. This effect can be obtained more significantly by performing heating under no pressure (in a state where no pressure is particularly applied). In addition, when the remolded object 43 is remolded inside the cavity 44a, the cavity 44a and the remolded object 43 can be bonded over the entire contact surface, so that the intermediate material 44 and the remolded object 43 can be bonded more firmly than a composite material having selective bonding points such as laser welding. Moreover, even if an external force acts on the composite material 45, it is possible to prevent a gap from being generated between them. As described above, a rod-shaped composite material 45 obtained by remolding the remolded object 43 inside the cavity 44a was used as a test piece, and a tensile test was performed by setting the intermediate material 44 and the remolded object 43 so as to separate them.It was confirmed that the joint between the intermediate material 44 and the remolded object 43 did not break, but broke at a location other than the joint.

[0050] In addition, when obtaining crosslinked PFA, it is also possible to select, for example, non-crosslinked PFA powder as a starting material without using a non-crosslinked PFA film. However, when crosslinked PFA powder is obtained from non-crosslinked PFA powder, the crosslinked PFA powder is remolded, but there is a problem that the melt is likely to contain gas when heated and melted. That is, the melt viscosity of crosslinked PFA is higher than that of non-crosslinked PFA, and the higher the degree of crosslinking, the higher the melt viscosity. Therefore, when trying to obtain abrasion resistance with priority, it requires time and cost for degassing, so it is preferable to use cut pieces of crosslinked PFA film from the viewpoint of excellent degassing ability during heat melting. In addition, crosslinked PFA film can be crushed into, for example, powder or fine particles, but it is less expensive to use cut pieces. Furthermore, it is preferable to use cut pieces from the viewpoint of more effectively maintaining the mechanical strength obtained by crosslinking.

[0051] As described above, when the entire intermediate material 44 is heated and the cut pieces 42 accommodated in the cavity 44a are heated and melted to obtain the remolded product 43 (firing process), the integration process can be performed simultaneously with the cooling and solidification, but the same effect can be obtained by the following method. That is, for example, the melted cut pieces 42 of the cross-linked PFA film can be injected into the cavity 44a provided in the intermediate material 44 to obtain the remolded product 43 in the cavity 44a, and the intermediate material 44 and the remolded product 43 can be integrated using an injection process. Also, after accommodating the cut pieces 42 of the cross-linked PFA film in the cavity 44a provided in the intermediate material 44 (cut piece accommodation process), the cut pieces 42 can be compressed in the cavity 44a to obtain the remolded product 43 and integrate the intermediate material 44 and the remolded product 43 (compression molding process). Heating can be performed at the same time as this compression. The heating may be performed at a temperature as required. For example, the heating may be performed at a temperature lower than the melting point of the cross-linked PFA, or may be performed at a temperature higher than the melting point of the cross-linked PFA.

[0052] On the other hand, when the remolded object 43 is obtained separately, an integration step is performed to obtain a composite material 45 by integrating the intermediate material 44 with the remolded object 43 accommodated in the cavity 44a (recess) of the intermediate material 44. The integration may be performed by any method, but for example, the integration can be performed by simultaneously heating both to a temperature equal to or higher than the higher of the melting points of the non-crosslinked fluororesin constituting the intermediate material 44 and the crosslinked PFA constituting the remolded object 43. That is, the intermediate material 44 and the remolded object 43 can be joined by melting at least one of them at least on its surface.

[0053] The intermediate material 44 and the remolded product 43 can also be joined by welding. That is, this can be achieved by providing a welding process for obtaining a composite material by welding the intermediate material 44 and the remolded product 43. This welding can be performed by, for example, laser welding, hot plate welding, hot air welding, heating block welding, diffusion bonding, etc. Each of these methods can be said to be a method of melting at least a part of the contact area between the intermediate material 44 and the remolded product 43 to weld them together.

[0054] 7(a) and 7(b) show a method for producing a diaphragm 3 from a composite material 45. A diaphragm 3 as shown in FIG. 7(b) can be produced by cutting a composite material 45 as shown by a dashed line in FIG. 7(a). The diaphragm 3 shown in FIG. 7(b) is used in the needle valve 1 shown in FIG. 1. In the diaphragm 3, a membrane portion 3b having a base portion 33a at the center is produced from an intermediate material 44 formed from a non-crosslinked fluororesin in the composite material 45. The non-crosslinked fluororesin constituting the intermediate material 44 is formed from PTFE from the viewpoint of high bending durability.

[0055] Moreover, the end 33b of the diaphragm 3 is formed of cross-linked PFA from the viewpoint of low dust generation. Moreover, in the composite material 45, the intermediate material 44 and the remolded product 43 are integrally bonded by sintering (integral melt molding). Therefore, the entire boundary surface (joint surface) between the base 33a and the end 33b of the diaphragm 3 is integrally bonded. Therefore, even if an impact is applied, no gap is generated at the boundary surface between the base 33a and the end 33b, and it is possible to prevent a decrease in strength due to the liquid in the valve chamber 6 penetrating into the gap. Moreover, since both the intermediate material 44 and the remolded product 43 are heated overall and then cooled, the occurrence of thermal strain is suppressed, and the decrease in strength due to thermal strain is also suppressed.

[0056] In addition, by cutting out the parts made from the composite material 45 from an appropriate position, it is possible to change which part of the part is made from a different fluororesin. That is, in Fig. 7(a) and Fig. 7(b), the tip side from the film part 3b is made from cross-linked PFA which generates less dust, but for example, as shown in Fig. 8(a) and Fig. 8(b), by changing the cutting position, it is possible to make the end part 33b made from cross-linked PFA smaller and the base part 33a made from non-cross-linked fluororesin larger. In this case, it is possible to make substantially only the needle part 3a from cross-linked PFA, and it is possible to obtain a needle valve 1 which generates less dust while keeping costs down.

[0057] Next, the action and effect of the needle valve 1 configured as above will be described. In the fully closed state of the needle valve 1 (see FIG. 4(a)), the fluid flowing in from the inlet flow path 8 is closed by the rib 4 of the valve body portion 3d being pressed against the valve seat surface 5b. When the handle 19 is rotated in the valve opening direction from the fully closed state, the first stem 16a rotates and rises, the rotation of the first stem 16a is transmitted to the second stem 16b, which rises, the diaphragm 3 connected to the second stem 16b rises, and the rib 4 of the valve body portion 3d moves away from the valve seat surface 5b. When the handle 19 is further rotated to raise the diaphragm 3, the needle portion 3a rises and the valve is in a half-open state. At this time, a part of the needle portion 3a is inserted into the flow path portion 5b. The opening area of ​​flow path section 5b minus needle section 3a becomes the area of ​​the passage, and the flow rate of flow path section 5b is adjusted by adjusting the area of ​​the passage. When adjusting the flow rate, the opening is adjusted by operating handle 19 so as to obtain the desired flow rate. When handle 19 is further rotated from the half-open state, stopper section 18 of first stem 16a is pressed against the ceiling surface of drive section housing 17, the rotation of first stem 16a is stopped, and needle valve 1 becomes fully open (see FIG. 4(b)).

[0058] As described above, when the needle valve 1 is fully closed, the rib 4 of the valve body 3d is pressed against the valve seat surface 5b to seal the fully closed state. When the opening is increased, the diaphragm 3 rises, and the needle portion 3a and the valve body 3d rise to the fully open state as the diaphragm 3 rises. Even when fully open, the needle portion 3a does not come out of the flow path portion 5b, and the flow rate is adjusted from fully closed to fully open. [Industrial Applicability]

[0059] INDUSTRIAL APPLICABILITY The present invention can be widely used as a needle valve having a diaphragm used for fluid control and a manufacturing method thereof. [Explanation of symbols]

[0060] 1; needle valve, 3; diaphragm, 3a; Needle part, 3b; Membrane part, 3c; Outer periphery part, 5; body; 5a; flow passage portion; 5b; valve seat surface; 6; Valve chamber, 7; inlet; 8; inlet channel; 9; Outlet; 10; outlet flow path, 12; recess, 13; base plate, 15; Drive unit, 16; stem, 16a; first stem, 16b; second stem, 17; drive unit housing, 17a; step portion, 18; stopper part, 19;Handle, 21; pressing member; 21a; step portion; 21b; fitting portion; 22; through hole, 24; through hole; 26, 27, 28; threaded part, 33a; base; 33b; end; 35a; base; 35b; end; 41; Cross-linked PFA film, 42; Cross-linked PFA film cut pieces, 43; remolding; 44; intermediate material, 44a; cavity, 45; composite materials, 46;Molds, C; Movement axis.

Claims

1. A needle valve comprising a diaphragm having a needle portion and a membrane portion extending outward from the needle portion and deformable in the direction of the movement axis, and a body having a valve chamber formed therein and a cylindrical flow path portion opening into the valve chamber, wherein the axis of the flow path portion coincides with that of the needle portion, and the opening area of ​​the flow path portion can be adjusted by the reciprocating movement of the needle portion in the direction of the movement axis due to the deformation of the membrane portion, Each of the needle portion and the flow channel portion is made of bridged PFA from one end to the other, and the tertiary carbon concentration at one end in each axial direction is M １ (Assuming mol%), the tertiary carbon concentration at the other end in each axial direction is M ２ (When expressed as mol%), M １ ≥0.01, M ２ ≥ 0.01, and 0.8 ≤ M １ / M ２ Satisfying ≤ 1.2, The diaphragm comprises a base made of non-crosslinked fluororesin, A needle valve characterized by having an end portion made of the bridging PFA, which is integrated with the base portion and includes the needle portion.

2. The body comprises a base made of non-crosslinked fluororesin, The needle valve according to claim 1, having an end portion which is integrated with the base portion and includes the flow channel portion and is made of the bridging PFA.

3. The needle valve according to claim 1, wherein the distance between the one end and the other end is 250 μm or more.

4. The needle valve according to claim 1, wherein the needle portion and the flow channel portion are made of a remolded product of a crosslinked PFA film crosslinked to have a tertiary carbon concentration of 0.01 mol% or more.

5. The needle valve according to claim 1, wherein the diaphragm and the body are cut from a composite formed by integrating an intermediate material made of a non-crosslinked fluororesin that forms the base and a remolded product of a crosslinked PFA film crosslinked to have a tertiary carbon concentration of 0.01 mol% or more.

6. A method for manufacturing a needle valve according to claim 1, A cutting process to obtain cut pieces of a crosslinked PFA film that has been crosslinked so that the tertiary carbon concentration is 0.01 mol% or more, A reshaping step to reshape the aforementioned cut pieces to obtain a reshaped product, A method for manufacturing a needle valve, comprising a forming step of obtaining the needle portion and the flow path portion from the remolded product.

7. A method for manufacturing a needle valve according to claim 6, comprising an integration step to obtain a composite material by integrating an intermediate material made of a non-crosslinked fluororesin and the remolded product.

8. The integration process includes a piece-filling step of filling the piece in a cavity provided in the intermediate material, A method for manufacturing a needle valve according to claim 7, comprising a firing step of melting the cut pieces in the cavity to obtain the remolded product and integrating the intermediate material and the remolded product.

9. The method for manufacturing a needle valve according to claim 7, wherein the integration step includes an injection step of injecting molten material of the cut fragments into a cavity provided in the intermediate material to obtain a remolded product within the cavity and to integrate the intermediate material and the remolded product.

10. The integration process includes a piece-filling step of filling the piece in a cavity provided in the intermediate material, A method for manufacturing a needle valve according to claim 7, comprising a compression molding step of compressing the cut pieces in the cavity to obtain the remolded product and integrating the intermediate material and the remolded product.

11. A method for manufacturing a needle valve according to claim 6, comprising a welding step to obtain a composite material by welding an intermediate material made of a non-crosslinked fluororesin and the previously obtained remolded product.

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