Needle valve and method for manufacturing same

Abstract

The purpose of the present invention is to provide a needle valve that reduces the generation of particles, and a manufacturing method of the needle valve. A needle valve 1 comprises: a diaphragm 3 having a needle part 3a and a deformable membrane part 3b extending outwards from the needle part 3a; and a body 5 in which a valve chamber 6 is formed and which has 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 made of cross-linked PFA from one end to another end, and a tertiary carbon concentration M1 (mol%) at the 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 comprises: a step for 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 for obtaining a re-molded object by re-molding the cut piece; and a step for obtaining a needle part and a flow path part from the re-molded object.

Description

Needle valve and its manufacturing method

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

[0002] Needle valves can be used to control various fluids in a variety of situations, including controlling the flow and volume of chemicals used in semiconductor manufacturing. In this case, the needle valve includes a body and a diaphragm made of a fluororesin, such as polytetrafluoroethylene (PTFE) or perfluoroalkoxyalkane (PFA), due to its excellent chemical resistance and flexural durability. The body includes a valve chamber connected to multiple flow paths, and the diaphragm is reciprocally movable within the valve chamber along its axis of movement. This allows the size of the gap between the needle portion, located at the bottom end of the diaphragm, and the flow path portion to be changed, thereby changing the flow rate.

[0003] In such needle valves, it is necessary to prevent particle generation due to contact between the needle and the flow path. Particles are micro-sized particles of the material that makes up the needle valve. The needle and the flow path 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 in assembly and dimensional tolerances of parts. Furthermore, since the needle and the flow path are in a liquid-contact area, particles generated in these areas may be mixed into the flowing chemical liquid. If the above-mentioned chemical liquid is, for example, a cleaning liquid used in semiconductor manufacturing, the flowing cleaning liquid may contain particles, resulting in a problem of reduced cleanliness during cleaning. To address this issue, the technology described in Patent Document 1 below is known.

[0004] Japanese Patent Application Laid-Open No. 2022-095226

[0005] The above-mentioned Patent Document 1 discloses a flow control valve having a degree of freedom in which a rod connected to a needle valve body has an annular elastic body on the outer peripheral surface thereof, and the rod can tilt around the elastic body as a fulcrum, in order to suppress wear even when the needle valve body makes partial contact with the annular valve seat. According to this configuration, when the needle valve body makes partial contact with the annular valve seat, the rod tilts, reducing the contact pressure applied to the needle valve body and suppressing wear. However, the degree of freedom cannot be increased without limit, and considering that the temperature of the chemical solution can reach high temperatures of around 200°C and dimensional changes such as expansion and contraction due to temperature changes, it is unlikely that sufficient wear resistance can be achieved by the degree of freedom alone. Furthermore, Patent Document 1 describes (

[0040] ,

[0024] ) the use of fluororesin (e.g., PFA or PTFE) for the needle valve body and the annular valve seat, but does not describe or suggest cross-linked fluororesin.

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a needle valve that can suppress the generation of particles, and a method for manufacturing the same.

[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 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 flow path portion is axially aligned with 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, wherein each of the needle portion and the flow path portion is made of cross-linked PFA from one end to the other, and the tertiary carbon concentration at one end in each axial direction is adjusted to M １ (mol %), and the tertiary carbon concentration at the other end in each axial direction is M ２ (mol %), M １ ≧0.01, M ２ ≧0.01 and 0.8≦M １ / M ２≦1.2. [2] The needle valve according to [1] above, wherein the diaphragm has a base made of a non-crosslinked fluororesin and an end portion integral with the base, comprising the needle portion and made of the crosslinked PFA. [3] The needle valve according to [1] or [2] above, wherein the body has a base made of a non-crosslinked fluororesin and an end portion integral with the base, comprising the flow path portion and made of the crosslinked PFA. [4] The needle valve according to any of [1] to [3] above, wherein the distance between the one end and the other end is 250 μm or more. [5] The needle valve according to any of [1] to [4] above, wherein the needle portion and the flow path portion are made of a remolded piece of a crosslinked PFA film crosslinked to have a tertiary carbon concentration of 0.01 mol % or more. [6] The needle valve according to [2] above, wherein the diaphragm and the body are cut from a composite formed by integrating an intermediate material made of a non-crosslinked fluororesin serving as the base and a remolded product of a cut piece of a crosslinked PFA film crosslinked to have a tertiary carbon concentration of 0.01 mol% or more. [7] The needle valve manufacturing method according to any of [1] to [6] above, comprising: a cutting step of obtaining a cut piece of a crosslinked PFA film crosslinked to have a tertiary carbon concentration of 0.01 mol% or more; a remolding step of remolding the cut piece to obtain a remolded product; and a forming step of obtaining the needle portion and the flow path portion from the remolded product. [8] The needle valve manufacturing method according to [7] above, comprising an integration step of obtaining a composite formed by integrating an intermediate material made of a non-crosslinked fluororesin and the remolded product. [9] The method for manufacturing a needle valve according to [8] above, wherein the integration step includes a cut piece accommodating step of accommodating the cut piece in a cavity formed in the intermediate material, and a firing step of melting the cut piece in the cavity to obtain the re-molded product and integrate the intermediate material and the re-molded product.

[10] The method for manufacturing a needle valve according to [8] or [9] above, wherein the integrating step includes an injection step of injecting a melt of the cut pieces into a cavity formed in the intermediate material to obtain the remolded product in the cavity and integrate the intermediate material with the remolded product.

[11] The method for manufacturing a needle valve according to any of [8] to

[10] above, wherein the integrating step includes a cut piece accommodating step of accommodating the cut pieces in a cavity formed in the intermediate material, and a compression molding step of compressing the cut pieces in the cavity to obtain the remolded product and integrate the intermediate material with the remolded product.

[12] The method for manufacturing a needle valve according to [7] above, comprising a welding step of welding an intermediate material made of a non-crosslinked fluororesin and the previously obtained remolded product to obtain a composite material.

[0008] The needle valve of the present invention can suppress the generation of particles.

[0009] That is, the needle portion and the flow passage portion each have a tertiary carbon concentration M １ (mol %), the tertiary carbon concentration M at the other end in each axial direction ２ (mol%) is M １ ≧0.01, M ２ ≧0.01 and 0.8≦M １ / M ２ In a needle valve that satisfies the condition ≦1.2, the needle portion from one end to the other in the axial direction and the flow path portion from one end to the other in the axial direction are formed of sufficiently cross-linked PFA, so that particle generation from these locations can be suppressed. １ and M ２ In comparison with a needle valve that does not satisfy the above relationship, the needle valve of the present invention can suppress particle generation.

[0010] In the 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, a non-crosslinked fluororesin, which has superior flexural durability compared to crosslinked PFA, can be used for the base, thereby improving the flexural durability of the membrane portion of the diaphragm in particular. Furthermore, 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 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, the base can be made of a non-crosslinked fluororesin, which has better flexural durability than crosslinked PFA, and therefore the membrane portion of the diaphragm can have excellent flexural durability. Furthermore, since the entire body does not need to be made of crosslinked PFA, the manufacturing cost of the needle valve can be reduced.

[0012] In the above-described needle valve, the distance between one end and the other end can be 250 μm or more. Normally, crosslinking a thick non-crosslinked PFA from both sides is difficult from the standpoint of radiation transmittance, but this can be achieved by the needle valve manufacturing method described below. Furthermore, by providing a needle portion and a flow path portion with this distance of 250 μm or more, wear on the needle portion and the flow path portion can be suppressed compared to when this 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 portion and flow path portion can be made from a remolded piece of a crosslinked PFA film crosslinked to a tertiary carbon concentration of 0.01 mol% or more. In other words, crosslinking a thick non-crosslinked PFA film to a tertiary carbon concentration of 0.01 mol% or more across the entire front and back is difficult from the standpoint of radiation transmittance. However, it is possible to irradiate a non-crosslinked PFA film of a thickness that allows this to be achieved, thereby obtaining a crosslinked PFA film with a tertiary carbon concentration of 0.01 mol% or more across the entire front and back. Furthermore, if a member made of crosslinked PFA is remolded from the cut pieces of this crosslinked PFA film, it can be a crosslinked PFA member that is uniformly crosslinked throughout, regardless of its thickness. By forming the needle portion and flow path portion from such a crosslinked PFA member with a uniform degree of crosslinking throughout, particle generation due to contact between the needle portion and the flow path portion can be significantly suppressed.

[0014] In the above-described needle valve, the diaphragm and body can be cut from a composite material that integrates an intermediate material made of a non-crosslinked fluororesin base and a remolded cut piece of a crosslinked PFA film that has been crosslinked to a tertiary carbon concentration of 0.01 mol% or more. In this case, a non-crosslinked fluororesin that has superior flexural durability compared to crosslinked PFA can be used as the base, thereby improving the flexural durability of the membrane portion of the diaphragm in particular. Furthermore, 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 manufacturing a needle valve of the present invention, it is possible to manufacture a needle valve that can suppress the generation of particles.

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

[0017] The needle valve manufacturing method can include an integration step of integrating an intermediate material made of a non-crosslinked fluororesin with a remolded product to obtain a composite material. In this case, since a non-crosslinked fluororesin with superior flexural durability compared to crosslinked PFA can be used, the membrane portion of the diaphragm can be formed from the intermediate material portion of the composite material, thereby improving the flexural durability of the membrane portion. Furthermore, since the diaphragm or the body does not need to be entirely made of crosslinked PFA, the manufacturing cost of the needle valve can be reduced. In the needle valve manufacturing method, the integration step can include a cut piece receiving step of receiving cut pieces in a cavity formed 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 with the remolded product. In addition, in the needle valve manufacturing method, the integration step can include an injection step of injecting the molten cut pieces into a cavity formed in the intermediate material to obtain a remolded product in the cavity and integrating the intermediate material with the remolded product. In the above-mentioned method for manufacturing a needle valve, the integration step can include a cut piece accommodation step of accommodating cut pieces in a cavity formed 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 with the remolded product. In the above-mentioned method for manufacturing a needle valve, the integration step can include a cut piece accommodation step of accommodating cut pieces in a cavity formed 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 with the remolded product. In addition, the above-mentioned method for manufacturing a needle valve can include a welding step of obtaining a composite material by welding an intermediate material made of a non-crosslinked fluororesin and a previously obtained remolded product. By including these steps, a composite material can be obtained by integrating an intermediate material made of a non-crosslinked fluororesin and a remolded product, as described above. Therefore, a diaphragm can be obtained that has a needle portion and a flow path portion entirely formed from uniformly crosslinked crosslinked PFA, as well as a membrane portion with excellent flexural durability. Furthermore, since it is not necessary to form the entire diaphragm or body from cross-linked PFA, the manufacturing cost of the needle valve can be reduced.

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

[0019] FIG. 1 is a longitudinal cross-sectional view of a needle valve according to an embodiment; FIG. 2 is a longitudinal cross-sectional view of a diaphragm constituting the needle valve; FIG. 3 is a longitudinal cross-sectional view of a body constituting the needle valve; FIG. 4 is an explanatory diagram of the operation of the needle valve, where (a) shows a fully closed state and (b) shows a fully open state; FIG. 5 is an explanatory diagram for explaining a method for manufacturing 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; FIG. 6 is an explanatory diagram for explaining a method for manufacturing a needle valve (a process for integrating an intermediate material and a remolded product), where (a) shows a perspective view of the intermediate material and the remolded product, and (b) shows a longitudinal cross-sectional view of the remolded product housed in the housing portion of the intermediate material; FIG. 7 is an explanatory diagram for explaining a method for manufacturing a needle valve (a process for forming a needle portion), where (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. 1 is an explanatory diagram for explaining a method for manufacturing a needle valve of another embodiment (a step of forming a needle portion), where (a) shows a longitudinal cross-section of a composite material, and (b) shows a longitudinal cross-section of a diaphragm obtained by cutting the composite material.

[0034] FIG. 1 is an explanatory diagram for explaining a method for manufacturing a needle valve of yet another embodiment (a step of forming a needle portion), where (a) shows a longitudinal cross-section of a composite material, and (b) shows a longitudinal cross-section of a diaphragm obtained by cutting the composite material.

[0035] FIG. 1 is an explanatory diagram for explaining a method for manufacturing a needle valve (a step of integrating an intermediate material with a remolded product), where (a) shows a perspective view of the intermediate material and the remolded product, and (b) shows a longitudinal cross-section of the remolded product housed in the housing portion of the intermediate material.

[0036] FIG. 2 is an explanatory diagram for explaining a method for manufacturing a needle valve (a step of forming a flow path), where (a) shows a longitudinal cross-section of a composite material, and (b) shows a longitudinal cross-section of a body obtained by cutting the composite material.

[0037] FIG. 2 is an explanatory diagram for explaining a method for manufacturing a needle valve of another embodiment (a step of integrating an intermediate material with a remolded product).

[0020] The matters set forth herein are for illustrative purposes only and are intended to provide an illustrative description of the embodiments of the present invention, with the aim 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 regard, 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, taken together with the drawings, will make clear to those skilled in the art how some forms of the present invention may be actually embodied.

[0021] The present invention will be specifically described below by way of examples with reference to the drawings.

[0022] 1, the needle valve 1 of this embodiment comprises 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 having a valve chamber 6 formed therein and a cylindrical flow path portion 5a opening into the valve chamber 6. In the needle valve 1, the flow path portion 5a is aligned with the axis of the needle portion 3a, and the opening area of ​​the flow path portion 5a can be adjusted by the reciprocating movement of the needle portion 3a in the direction of the movement axis C due to deformation of the membrane portion 3b. The needle valve 1 also comprises a drive unit 15 that drives the diaphragm 3.

[0023] The diaphragm 3 is positioned to close the upper opening of the valve chamber 6 and is fixed to the body 5. The diaphragm 3 has a central needle portion 3a, an annular membrane portion 3b that is thin-walled to facilitate bending and supports the needle portion 3a, and an outer peripheral edge portion 3c that is provided on the outer periphery of the membrane portion 3b (see FIG. 2). The diaphragm 3 also has a valve body portion 3d that is positioned to surround the needle portion 3a. The diaphragm 3 also has a connection portion 3e that is provided above the needle portion 3a and is connected to the stem 16 of the actuator 15. The diaphragm 3 supports the needle portion 3a and valve body portion 3d within the valve chamber 11 via the membrane portion 3b, thereby separating the valve chamber 6 from the actuator 15.

[0024] The needle portion 3a protrudes toward the flow path 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 narrows toward the flow path portion 5a. The shape of the flow path portion 5a (the flow path defined by the inner periphery of the flow path portion 5a) in a cross section (transverse cross section) perpendicular to the axial direction corresponds to the shape of the needle portion 3a in the same transverse cross section (for example, both are circular). Furthermore, each part is formed and assembled so that the center of the flow path portion 5a in the same transverse cross section substantially coincides with the center of the needle portion 3a in the same transverse cross section. Therefore, by adjusting the insertion position of the needle portion 3a relative to the flow path portion 5a, the size of the flow path defined by the inner periphery of the flow path portion 5a and the outer periphery of the needle portion 3a is adjusted, and the flow rate of the flow path portion 5a is adjusted.

[0025] The membrane portion 3b is configured to expand radially outward from the needle portion 3a. More specifically, it is formed 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 generally circular shape. The outer peripheral edge portion 3c has an L-shaped cross section. At least a portion of the outer peripheral edge portion 3c is sandwiched between the body 5 and the presser member 21. The valve body portion 3d is provided with an annular rib 4 that protrudes 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. A threaded portion 26 that meshes with each other is formed on the outer peripheral surface of the connection portion 3e and on the inner peripheral surface of the lower end of the stem 16. 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 using the drive unit 15.

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

[0027] As shown in Figure 2, the diaphragm 3 has a base 33a made of a non-crosslinked fluororesin and an end portion 33b made of crosslinked PFA, which is integrated with the base 33a and has a needle portion 3a. Specifically, the base 33a, including the membrane portion 3b, is made of a non-crosslinked fluororesin, which is less expensive than crosslinked PFA and has high flexural durability. The end portion 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 that forms the base 33a, and a remolded product 43 (remolded product 43 that forms the end portion 33b) of a cut piece 42 of a crosslinked PFA film crosslinked to a tertiary carbon concentration of 0.01 mol% or more (see Figures 7 to 9).

[0028] The type of fluororesin constituting the non-crosslinked fluororesin is not limited, and may be tetrafluoroethylene [F ２ C=CF ２ ], hexafluoropropene [F ２ C=CF ２ -CF ３ ], difluoroethylene [H ２ C=CF ２ ], chlorotrifluoroethylene [F ２ C=CFCl], perfluoroalkoxyethylene (perfluoromethoxyethylene [F ２ C=CF-O-CF ３ ], perfluoroethoxyethylene [F ２ C=CF-O-CF ２ -CF ２Polymers (homopolymers or copolymers) using fluorine-substituted polymerizable compounds such as ethylene (non-fluorine-substituted ethylene) as monomers can be used. Among these, ethylene (non-fluorine-substituted ethylene) can be used as the 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 preferred for the base 33a because it is less likely to melt when heated, can maintain its shape by gelation, and can reduce material costs.

[0029] Furthermore, crosslinking in fluororesin refers to the formation of carbon-carbon bonds between different polymer molecules that make up the fluororesin. Therefore, while non-crosslinked PFA typically does not contain tertiary carbon, crosslinked PFA does. Therefore, the presence or absence of tertiary carbon corresponds to the presence or absence of crosslinks within the PFA, and it can be seen that the higher the tertiary carbon concentration, the more crosslinks there are within the PFA. In the present invention, a tertiary carbon concentration of 0.01 mol% or higher is considered crosslinked. The upper limit of this tertiary carbon concentration is not limited, but is typically 0.7 mol% or less. Maintaining a tertiary carbon concentration of 0.7 mol% or less allows the mechanical strength of the crosslinked PFA to be maintained at a high level.

[0030] The tertiary carbon concentration of cross-linked PFA １９ F-NMR measurement (measuring device: solid １９The 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 the tertiary carbon concentration is calculated (based on Peak C) using the following calculation formula (1). The presence of tertiary carbon can be determined by the presence of Peak C and / or Peak G, but as described above, the tertiary carbon concentration is basically calculated according to Calculation Formula (1) using the peak intensity of Peak C. However, if Peak C is not detected and only Peak G is detected, the tertiary carbon concentration is calculated using the following Calculation Formula (2). This is because the tertiary carbon concentration calculated by Calculation Formula (1) and the tertiary carbon concentration calculated by Calculation Formula (2) are usually substantially the same value.

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

[0032] [Calculation 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]

[0034] The needle portion 3a is made of cross-linked PFA from one end to the other end, and the tertiary carbon concentration at one end is M １ (mol %), and the tertiary carbon concentration at the other end is M ２ (mol %), M １ >0.01, M ２ >0.01 and 0.8≦M １ / M ２ ≦1.2. That is, the needle portion 3 a has a tertiary carbon concentration M １ is greater than 0.01 mol %, and at the same time, the tertiary carbon concentration M ２ In addition, these M １ and M ２ Ratio to (M １ / M ２ ) is 0.8 or more and 1.2 or less, and M １ and M ２ Therefore, the needle portion 3a is formed from a cross-linked PFA that is uniformly cross-linked from one end to the other end. １ The diameter of the needle portion 3a is approximately 250 to 6000 μm (see FIG. 2), and is set to be 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 crosslinked PFA uniformly crosslinked from one end to the other, can be formed in any manner, but can be formed from a remolded product 43 of a cut piece 42 of a crosslinked PFA film 41 crosslinked to a tertiary carbon concentration of 0.01 mol% or more (see Figure 5). That is, for example, a thin film of non-crosslinked PFA less than 250 μm thick can be irradiated with radiation so that it reaches both the front and back of the film. On the other hand, for example, a thick film of non-crosslinked PFA greater than 250 μm thick makes it difficult for radiation to penetrate, resulting in a crosslinked PFA film with different degrees of crosslinking on the front and back. It is also possible to increase the radiation output to penetrate both the front and back of the non-crosslinked PFA film, but this can result in different degrees of crosslinking on the front and back due to attenuation during penetration. Furthermore, the use of high-power radiation leads to a rapid increase in costs, making it difficult to adopt. Therefore, in order to obtain crosslinked PFA at low cost and with a high degree of freedom in shape while ensuring crosslinking, a thin film of non-crosslinked PFA less than 250 μm is irradiated with radiation so that it penetrates both the front and back of the film to uniformly crosslink the film, and then the cut pieces 42 obtained by cutting the film are remolded to obtain crosslinked PFA with a uniformly crosslinked desired shape. Furthermore, for example, among fluororesins, PTFE is difficult to melt-form, regardless of whether it is crosslinked or not. In contrast, PFA can be melt-formed even after crosslinking, so it is possible to obtain a block-shaped crosslinked PFA 43 by remolding the cut pieces 42 of the crosslinked PFA film 41.

[0036] The body 5 is formed with a valve chamber 6 at its upper center, and with first and second flow paths communicating with the valve chamber 6. The body 5 is also formed with a flow path portion 5a, where the needle portion 3a faces the opening from the first flow path to the valve chamber 6. The upper end surface of the flow path portion 5a of the body 5 forms 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 path is an inlet flow path 8, which 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 path 8 to the valve chamber 6. The second flow path is an outlet flow path 10, which 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 path 10 opens to the outside of the bottom of the valve chamber 6 and is formed to be at the same height as the inlet flow path 8.

[0037] The upper part of the body 5 is provided with a recess 12 that receives the fitting portion 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, body 5, and base plate 13 are fastened together 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 portion 35b made of crosslinked PFA, which is integrated with the base 35a and includes a flow path portion 5a (see FIG. 11 ). Specifically, the base 35a (specifically, a portion of the body 5 having a larger volume than the end portion 35b) is made of a non-crosslinked fluororesin, which is less expensive than crosslinked PFA. The end portion 35b, including the flow path portion 5a, is made of crosslinked PFA, which has high abrasion resistance and strength. Furthermore, the body 5 is cut from a composite material 45, which integrates an intermediate material 44 made of a non-crosslinked fluororesin that forms the base 35a, and a remolded product 43 (i.e., the remolded product 43 that forms the end portion 35b) of a cut piece 42 of a crosslinked PFA film crosslinked to a tertiary carbon concentration of 0.01 mol % or more (see FIGS. 5 , 10 , and 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, polymers (homopolymers or copolymers) using fluorine-substituted polymerizable compounds such as tetrafluoroethylene, hexafluoropropene, difluoroethylene, chlorotrifluoroethylene, perfluoroalkoxyethylene (perfluoromethoxyethylene, perfluoroethoxyethylene) as monomers can be used. Of these, ethylene (non-fluorine-substituted ethylene) can be used as the copolymer monomer. 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 preferred for the base 35a from the viewpoints of suppressing melting due to heating, maintaining shape by gelation, and reducing material costs. Furthermore, crosslinking in the fluororesin is also as described above in the description of the diaphragm 3.

[0040] The flow path 5a has a tertiary carbon concentration at one end in the axial direction of M １ (mol %), and the tertiary carbon concentration at the other end in the axial direction is M ２ (mol %), M １ >0.01, M ２ >0.01 and 0.8≦M１ / M ２ ≦1.2. Therefore, the flow path portion 5a is formed from cross-linked PFA that is uniformly cross-linked in the axial direction, and has high abrasion resistance and strength. Furthermore, the flow path portion 5a is formed from a remolded product 43 of a cut piece 42 of a cross-linked PFA film that is cross-linked so that the tertiary carbon concentration is 0.01 mol% or more. The flow path portion 5a has a distance D between one end and the other end. ２ The thickness D of the flow path portion 5a is about 250 to 6000 μm (see FIG. 2), and is set to 250 μm or more. ３ The thickness is about 250 to 12,000 μm (see FIG. 2), and is set to be 250 μm or more.

[0041] The flow path section 5a, made of crosslinked PFA uniformly crosslinked from one end to the other, can be formed in any manner, but can be formed from a remolded product 43 of a cut piece 42 of a crosslinked PFA film 41 crosslinked to a tertiary carbon concentration of 0.01 mol% or more (see Figure 5). That is, for example, a thin film of non-crosslinked PFA less than 250 μm thick can be irradiated with radiation so that it reaches both the front and back of the film. On the other hand, for example, a thick film of non-crosslinked PFA greater than 250 μm thick makes it difficult for radiation to penetrate, resulting in a crosslinked PFA film with different degrees of crosslinking on the front and back. While it is possible to increase the output of radiation to penetrate both the front and back of the non-crosslinked PFA film, this can result in different degrees of crosslinking on the front and back due to attenuation during penetration. Furthermore, using high-output radiation leads to a rapid increase in costs, making it difficult to adopt. Therefore, in order to obtain crosslinked PFA at low cost and with a high degree of freedom in shape while ensuring crosslinking, a thin film of non-crosslinked PFA less than 250 μm is irradiated with radiation so that it penetrates both the front and back of the film to uniformly crosslink the film, and then the cut pieces 42 obtained by cutting the film are remolded to obtain crosslinked PFA with a uniformly crosslinked desired shape. Furthermore, for example, among fluororesins, PTFE is difficult to melt-form, regardless of whether it is crosslinked or not. In contrast, PFA can be melt-formed even after crosslinking, so it is possible to obtain a block-shaped crosslinked PFA 43 by remolding the cut pieces 42 of the crosslinked PFA film 41.

[0042] The aforementioned driver 15 is manually operated to move the diaphragm 3 together with the stem 16 back and forth in the axial direction to adjust the position of the needle 3a relative to the flow path 5a. The driver 15 moves the stem 16 by a screw mechanism that utilizes thread engagement. Specifically, the driver 15 is composed of a threaded portion 27 that is provided to engage with the inner circumferential surface of the through-hole 24 of the driver housing 17 and the outer circumferential surface of the first stem 16a, and a threaded portion 28 that is provided to engage with the inner circumferential surface of the first stem 16a and the outer circumferential surface of the second stem 16b. However, the driver 15 is not limited to a manually operated screw mechanism. For example, the driver 15 may be driven by fluid pressure (such as air pressure) or by an electric actuator including 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 from the flow path portion 5a. The stem 16 has a first stem 16a and a second stem 16b connected to the first stem 16a via a threaded portion 28. The connection portion 3e of the diaphragm 3 is connected to the lower end of the second stem 16b via a threaded 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 extending 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 portion of the second stem 16b is hexagonal.

[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 stepped portion 17a with a hexagonal inner peripheral surface is provided at the lower portion of the drive unit housing 17. The presser member 21 is also made of PVDF. The presser member 21 has the stepped portion 21a and a cylindrical fitting portion 21b provided on the lower outer peripheral side of the stepped portion 21a. The stepped portion 21a and the fitting portion 21b all have hexagonal outer peripheral surfaces. A through-hole 22 with a hexagonal inner peripheral surface is formed in the center of the presser member 21. The lower portion of the second stem 16b is non-rotatably inserted into the through-hole 22. The stepped portion 21a of the presser member 21 is non-rotatably fitted into the stepped portion 17a of the drive unit housing 17. Furthermore, the fitting portion 21b of the pressing member 21 is fitted non-rotatably into the recess 12 of the body 5. As a result, the pressing member 21 supports the second stem 16b so that it can move up and down and cannot rotate.

[0045] Next, a method for manufacturing the needle valve 1 having the above configuration will be described. First, an intermediate member 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, a cup-shaped intermediate member 44 having a recess at its upper end that functions as the cavity 44a is made, as shown in FIG. 6 (for manufacturing the diaphragm 3) and FIG. 10 (for manufacturing the body 5). The intermediate member 44 may be formed by any method, but may be made, for example, by forming a recess by cutting the upper end of a rod-shaped body or plate that has been compression-molded from the non-crosslinked fluororesin using a mold by a free baking method, hot molding method, or the like. Similarly, a cup-shaped rod-shaped body or plate having a recess at its upper end may also be made by compression-molding from the non-crosslinked fluororesin using a mold by a free baking method, hot molding method, or the like. Furthermore, the intermediate member 44 does not need to be integrally formed. For example, it can be formed 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 threading or by fitting of recesses and protrusions. 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 formed separately and then joined by welding. Welding can be performed by, for example, laser welding, hot plate welding, hot air welding, heating block welding, diffusion bonding, baking, etc. When the intermediate member 44 is formed from a rod-shaped body of non-crosslinked fluororesin, the rod-shaped body of non-crosslinked fluororesin may be formed by extrusion molding.

[0046] Meanwhile, a remolded product 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 crosslinked PFA (remolding process). The remolded product 43 may be remolded at a location 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 circumferential shape is complementary to the inner circumferential 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 to a tertiary carbon concentration of 0.01 mol% or more can be used as the raw material for the crosslinked PFA. That is, for example, as shown in Figure 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 radiation to a thin film of non-crosslinked PFA, it is possible to obtain a crosslinked PFA film that is uniformly crosslinked on both sides. More specifically, by irradiating radiation in a temperature environment equal to or higher than the melting point of the non-crosslinked PFA with an acceleration 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 with respect to the thickness of the non-crosslinked PFA film to be irradiated, it is possible to obtain a crosslinked PFA film having a tertiary carbon concentration of 0.01 mol% or more on both sides of the film.

[0047] Then, as shown in FIG. 5( b), the crosslinked PFA film that has been uniformly crosslinked across its front and back surfaces is cut to obtain cut pieces 42, thereby obtaining a crosslinked PFA material with greater shaping flexibility. Furthermore, as shown in FIG. 5( c), the cut pieces 42 of the crosslinked PFA film are placed in the cavity of a mold 46 having a predetermined shape, heated and melted, and then solidified to obtain a remolded product 43. This remolded product 43 can be shaped by cutting or other methods to fit into the cavity 44a of the intermediate material 44, and then placed in the cavity 44a. Furthermore, for example, from the standpoint of being able to heat-melt it, the height of the remolded product 43 may be approximately equal to or shorter than the depth of the cavity 44a, as long as it does not overflow the cavity 44a when heated and melted. The remolded product 43 can also be produced directly from the crosslinked PFA, for example, by extrusion molding or injection molding using a mold.

[0048] On the other hand, when reforming the remolded product 43 inside the cavity 44a, as shown in FIG. 12, the cut pieces 42 of the crosslinked PFA film described above are placed in the cavity 44a (cut piece placement process) and heated and melted in the cavity 44a, thereby obtaining a remolded product 43 made of crosslinked PFA having a shape complementary to the inner circumferential surface of the cavity 44a. In this case, it is possible to heat and melt only the cut pieces 42 of the crosslinked PFA film placed in the cavity 44a, but it is also possible to heat the cavity 44a as well. That is, for example, the entire intermediate material 44 can be heated. This method is suitable for use when the intermediate material 44 is made of non-crosslinked PTFE. Non-crosslinked PTFE gels and does not melt even at the temperature at which 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 piece 42 of the cross-linked PFA film is heated and melted, it is remolded into a shape corresponding to the cavity 44a, and then cooled and solidified, at the same time the cavity 44a is also cooled and solidified, at which point the two (intermediate material 44 and remolded product 43) are integrated, resulting in a composite material 45 (firing process).

[0049] In this way, by reforming the remolded product 43 inside the cavity 44a, the production of the remolded product 43 and the integration of the resulting remolded product 43 with the intermediate material 44 can be achieved by a single heating / melting / cooling / solidification process, thereby achieving excellent manufacturing efficiency. Furthermore, since a mold for obtaining the remolded product 43 is not required, needle valves can be manufactured at low cost. Furthermore, when the remolded product 43 is obtained inside the cavity 44a while heating the entire intermediate material 44, the occurrence of distortion and residual stress can be suppressed, thereby achieving excellent bonding strength between the two. This effect can be more pronounced by heating under no pressure (no particular pressure is applied). Furthermore, when the remolded product 43 is reformed inside the cavity 44a, the entire contact surface between the cavity 44a and the remolded product 43 can be bonded, resulting in a stronger bond between the intermediate material 44 and the remolded product 43 compared to composite materials that have selective bonding locations, such as those formed by laser welding. Furthermore, it is possible to prevent a gap from being generated between the two even when an external force is applied to the composite material 45. As described above, when a rod-shaped composite material 45 obtained by remolding the remolded product 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 product 43 so as to separate them, it was confirmed that the joint between the intermediate material 44 and the remolded product 43 did not break, but broke at a location other than the joint.

[0050] In addition, when obtaining crosslinked PFA, it is possible to select, for example, non-crosslinked PFA powder as the 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, which poses the problem of the melt being more 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 prioritizing abrasion resistance, degassing requires effort and cost, so it is preferable to use cut pieces of crosslinked PFA film from the perspective of excellent degassing properties during heat melting. Furthermore, crosslinked PFA film can be pulverized into, for example, powder or fine particles, but cutting into cut pieces is less expensive. Furthermore, it is preferable to use cut pieces from the perspective of more effectively maintaining the mechanical strength obtained by crosslinking.

[0051] As described above, when the entire intermediate material 44 is heated to heat and melt the cut pieces 42 contained in the cavity 44a to obtain the remolded product 43 (firing process), the integration process can be performed simultaneously as the material cools and solidifies. However, the same effect can also be achieved by other methods, such as the following. That is, for example, a melt of the cut pieces 42 of the crosslinked PFA film can be injected into the cavity 44a of the intermediate material 44 to obtain the remolded product 43 within the cavity 44a, and the intermediate material 44 and the remolded product 43 can be integrated using an injection process. Alternatively, the cut pieces 42 of the crosslinked PFA film can be accommodated in the cavity 44a of the intermediate material 44 (cut piece accommodation process), and then the cut pieces 42 can be compressed within 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 simultaneously during this compression. The heating temperature can be set as required, and for example, the heating may be performed at a temperature lower than the melting point of the cross-linked PFA, or at a temperature higher than the melting point of the cross-linked PFA.

[0052] On the other hand, if the remolded product 43 is obtained separately, an integration step is performed to integrate the intermediate material 44 and the remolded product 43 contained in its cavity 44a (recess) to obtain a composite material 45. The integration may be performed by any method, but for example, the integration can be achieved by simultaneously heating both materials to a temperature equal to or higher than the melting point of the non-crosslinked fluororesin constituting the intermediate material 44 and the melting point of the crosslinked PFA constituting the remolded product 43, whichever is higher. That is, the intermediate material 44 and the remolded product 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 in which the intermediate material 44 and the remolded product 43 are welded together. 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 portion 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. The diaphragm 3 shown in FIG. 7(b) can be produced by cutting the composite material 45 as shown by the 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, the membrane portion 3b having the base portion 33a in the center is produced from an intermediate material 44 in the composite material 45, which is made of a non-crosslinked fluororesin. Note that the non-crosslinked fluororesin that constitutes the intermediate material 44 is made of PTFE, which has high flexural durability.

[0055] Furthermore, the end 33b of the diaphragm 3 is formed from cross-linked PFA, which generates little dust. In the composite material 45, the intermediate material 44 and the re-molded material 43 are integrally bonded by sintering (integral melt molding). Therefore, the entire boundary surface (joint surface) between the base 33a and end 33b of the diaphragm 3 is integrally bonded. Therefore, even if an impact is applied, no gaps are generated at the boundary surface between the base 33a and end 33b, and a decrease in strength due to liquid in the valve chamber 6 penetrating into the gaps can be prevented. Furthermore, because both the intermediate material 44 and the re-molded material 43 are heated and then cooled overall, the occurrence of thermal strain is suppressed, and a decrease in strength due to thermal strain is also suppressed.

[0056] Note that by cutting out a part made from the composite material 45 at an appropriate position, it is possible to change which areas of the part are made from different fluororesins. That is, in Figures 7(a) and 7(b), the tip side of the film portion 3b is made from cross-linked PFA, which has low dust-generating properties. However, as shown in Figures 8(a) and 8(b), for example, by changing the cutting position, it is possible to make the end portion 33b made from cross-linked PFA smaller and the base portion 33a made from non-cross-linked fluororesin larger. In this case, essentially, only the needle portion 3a can be made from cross-linked PFA, and a needle valve 1 with low dust-generating properties can be obtained at lower costs.

[0057] Next, the operation and effect of the needle valve 1 configured as described above will be described. When the needle valve 1 is in the fully closed state (see FIG. 4( a)), the fluid flowing in from the inlet flow path 8 is blocked by the rib 4 of the valve body 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 then rises. The diaphragm 3 connected to the second stem 16b rises, and the rib 4 of the valve body 3d moves away from the valve seat surface 5b. When the handle 19 is further rotated to raise the diaphragm 3, the needle 3a rises, resulting in a half-open state. At this time, a portion of the needle 3a is inserted into the flow path 5b. The opening area of ​​flow path portion 5b minus needle portion 3a is the area of ​​the passage, and the flow rate of flow path portion 5b is adjusted by adjusting the area of ​​the passage. To adjust the flow rate, the handle 19 is operated to adjust the opening to achieve the desired flow rate. When the handle 19 is further rotated from the half-open state, the stopper portion 18 of the first stem 16a presses against the ceiling surface of the drive unit housing 17, stopping the rotation of the first stem 16a and bringing the needle valve 1 into the fully open state (see FIG. 4(b)).

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

[0059] The present invention can be widely used as a needle valve having a diaphragm used for fluid control and a method for manufacturing the same.

[0060] REFERENCE SIGNS LIST 1 needle valve, 3 diaphragm, 3a needle portion, 3b membrane portion, 3c outer peripheral edge portion, 5 body, 5a flow path portion, 5b valve seat surface, 6 valve chamber, 7 inlet port, 8 inlet flow path, 9 outlet port, 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 portion, 19 handle, 21 pressing member, 21a step portion, 21b fitting portion, 22 through hole, 24 through hole, 26, 27, 28 threaded portion, 33a base portion, 33b end portion, 35a base portion, 35b end portion, 41: Crosslinked PFA film, 42: Cut pieces of crosslinked PFA film, 43: Remolded material, 44: Intermediate material, 44a: Cavity, 45: Composite material, 46: Mold, 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, the flow path portion being aligned with the axis of the needle portion, and the opening area of ​​the flow path portion being adjustable by the reciprocating movement of the needle portion in the direction of the movement axis due to the deformation of the membrane portion, wherein each of the needle portion and the flow path portion is made of cross-linked PFA from one end to the other, and the tertiary carbon concentration of one end in each axial direction is adjusted to M １ (mol %), and the tertiary carbon concentration at the other end in each axial direction is M ２ (mol%), M １ ≧0.01, M ２ ≧0.01 and 0.8≦M １ / M ２ A needle valve characterized in that it satisfies ≦1.

2.

2. The needle valve according to claim 1, wherein the diaphragm has: a base made of a non-crosslinked fluororesin; and an end portion which is integrated with the base, has the needle portion, and is made of the crosslinked PFA.

3. The needle valve according to claim 1, wherein the body has: a base made of a non-crosslinked fluororesin; and an end portion which is integrated with the base, has the flow path portion, and is made of the crosslinked PFA.

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

5. A needle valve as described in claim 1, wherein the needle portion and the flow path portion are made from 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. A needle valve as described in claim 2, wherein the diaphragm and the body are cut from a composite body comprising 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 as described in claim 1, comprising: a cutting step for obtaining cut pieces of a crosslinked PFA film crosslinked so that the tertiary carbon concentration is 0.01 mol% or more; a remolding step for remolding the cut pieces to obtain a remolded product; and a forming step for obtaining the needle portion and the flow path portion from the remolded product.

8. The method for manufacturing a needle valve according to claim 7, further 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. A method for manufacturing a needle valve as described in claim 8, wherein the integration process includes a cut piece accommodating process for accommodating the cut piece in a cavity provided in the intermediate material, and a sintering process for melting the cut piece in the cavity to obtain the remolded product and integrate the intermediate material with the remolded product.

10. A method for manufacturing a needle valve as described in claim 8, wherein the integration process includes an injection process in which a molten material of the cut piece is injected 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. A method for manufacturing a needle valve as described in claim 8, wherein the integration process includes a cut piece accommodating process for accommodating the cut piece in a cavity provided in the intermediate material, and a compression molding process for compressing the cut piece in the cavity to obtain the remolded product and integrate the intermediate material with the remolded product.

12. A method for manufacturing a needle valve as set forth in claim 7, further comprising a welding step of obtaining a composite material by welding an intermediate material made of a non-crosslinked fluororesin and the previously obtained remolded product.

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