Method for producing resin joined body

Abstract

To join two resin molded bodies formed of different fluororesin materials without depending on mechanical joining and so as not to generate the lowering of the strength of a joining surface.SOLUTION: A resin-junction body manufacturing method for manufacturing a junction body in which molded bodies formed of a fluororesin material are joined together includes the steps of: forming a first resin-molded body 51 of a shape having an accommodating portion 51a from a first fluororesin material that gels and maintains its shape at a melting temperature or higher; accommodating in the accommodating portion 51a a second resin-molded body 53 made of a second fluororesin material that melts and liquefies at the melting temperature or higher; and heating the first resin-molded body 51 in which the second resin-molded body 53 is disposed in the accommodating portion 51a to the melting temperature or higher and then cooling the first resin-molded body 51 and the second resin-molded body 53.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for producing a resin joined body by joining two resin molded bodies made of different fluorine-based resin materials. [Background technology]

[0002] For example, when controlling the flow rate of chemicals used in semiconductor manufacturing equipment, diaphragm valves are often used. These valve valves have a diaphragm with a diaphragm that separates the flow path or valve chamber through which the chemical flows from the actuator and a valve body supported at the center of the diaphragm. In diaphragm valves, the diaphragm repeatedly elastically deforms to move the valve body toward and away from the valve seat, thereby controlling the flow rate. Since such diaphragms come into contact with the chemicals, they require chemical resistance and flexural durability due to the repeated elastic deformation. For this reason, diaphragms are typically made from polytetrafluoroethylene (PTFE), which has high flexural durability. Because PTFE cannot be injection molded, diaphragms are manufactured by cutting a block that is compression-molded and then sintered from powdered PTFE. However, PTFE tends to generate dust, which can generate particles from the diaphragm's valve body, which repeatedly contacts and separates from the valve seat. In semiconductor manufacturing, the inclusion of particles in the chemicals significantly impacts the yield of semiconductor manufacturing. Therefore, it is preferable to suppress dust generation from the valve body portion of the diaphragm that comes into contact with the chemical solution.

[0003] One method for suppressing dust generation from the valve body is to form the valve body from perfluoroalkoxyalkane (PFA), a fluororesin material that is less likely to generate dust. However, PFA has low flexural durability, making it unsuitable for use in diaphragms that undergo repeated elastic deformation. Therefore, it has been proposed to join a valve body made from PFA to a diaphragm made from PTFE. Thus, there is a demand for joining molded bodies made from different fluororesin materials, and solutions to this demand have also been proposed.

[0004] For example, Patent Document 1 discloses a fluid control valve in which a diaphragm member (i.e., diaphragm portion) is formed from PTFE, a first fluororesin material, and is provided with a diaphragm membrane and a rod-shaped portion provided in the center of the diaphragm membrane, and has an outer circumferential uneven surface on the outer periphery of part of the rod-shaped portion; this diaphragm member is formed from PTFE, the first fluororesin material, and a valve seat abutment member (i.e., valve portion) is formed from PFA, a second fluororesin material that can be injection molded, and has a valve seat abutment surface and a recessed portion provided on the opposite side thereof; the rod-shaped portion is fitted into the recessed portion so that the outer circumferential uneven surface formed on the outer periphery of the rod-shaped portion of the diaphragm member and the inner circumferential uneven surface formed on the inner periphery of the recessed portion of the valve seat abutment member are tightly engaged with each other, thereby joining the diaphragm member and the valve seat abutment member. Furthermore, Patent Document 1 discloses a method for manufacturing a fluid control valve, which includes an insert molding process in which a second round rod is injection-molded from a second fluororesin material with a first round rod formed from a first fluororesin material inserted therein, followed by cutting the first round rod into the shape of the diaphragm member and the second round rod into the shape of the valve seat abutment member. Patent Document 2 discloses a method for manufacturing a fluid control device, in which a valve body is formed by combining a main member and a seating member that abuts against the valve seat, and the contact surface between the seating member material and the main member material is melted by irradiation with an infrared beam or a hot plate, and then machined from the welded combined material to produce the combined body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6873991 [Patent Document 2] Japanese Patent Application Publication No. 2020-200840 Summary of the Invention [Problem to be solved by the invention]

[0006] In the technology disclosed in Patent Document 1, when two resin molded bodies made of different fluororesin materials are joined by engaging their concave and convex surfaces (mechanical bonding), if an impact is applied to the resin joined body, such as when the valve body and valve seat abut when the valve is closed, minute gaps may form between the concave and convex surfaces due to differences in hardness of the materials. Furthermore, temperature changes in the fluid can also cause the joined body to expand and contract, creating minute gaps between the concave and convex surfaces. In particular, in fluid devices such as valves, if liquid penetrates and accumulates in such gaps, this can lead to deterioration of the valve body and the problem of particles increasing over time.

[0007] Furthermore, even when a joined body is formed by insert molding, as in the technology disclosed in Patent Document 1, the temperature difference between the molded body that serves as the insert and the injection-molded resin material becomes large, which can cause thermal strain on the uneven surface and reduce the strength of the joined surface. Similarly, even when two resin molded bodies are welded at their joining surfaces using an infrared beam or a hot plate, as in the technology disclosed in Patent Document 2, the temperature difference between the molten joining surface and the unmelted part becomes large, which can cause thermal strain and reduce the strength of the joined surface.

[0008] Therefore, an object of the present invention is to solve the problems present in the prior art by joining two resin molded bodies made of different fluororesin materials without relying on mechanical bonding and without causing a decrease in the strength of the joining surface. [Means for solving the problem]

[0009] In consideration of the above object, the present invention provides a method for producing a resin joined body by joining two resin molded bodies made of different fluororesin materials, the method comprising the steps of: forming a cup-shaped first resin assembly having a cylindrical container from a first fluororesin material that can gel and maintain its shape even at or above its melting point; accommodating a second resin assembly made of a second fluororesin material that melts and becomes liquid at or above its melting point, into the container; and heating the first resin assembly containing the second resin assembly in the container to or above the melting points of the first and second fluororesin materials, and then cooling the first resin assembly to transform the first resin assembly into a first resin molded body and the second resin assembly into a second resin molded body, and joining the first resin molded body and the second resin molded body together.

[0010] In the above-described method for producing a resin bonded body, a second resin assembly made of a second fluororesin material is accommodated in a cylindrical accommodation portion of a cup-shaped first resin assembly made of a first fluororesin material, so that the second fluororesin material can be easily retained within the first resin assembly regardless of its shape. Furthermore, since the first resin assembly is formed from a first fluororesin material that can gel (i.e., become gel-like) and maintain its shape even when melted at or above its melting point, the second resin assembly can be maintained in the accommodation portion of the first resin assembly even when the second resin assembly made of the second fluororesin material melts and becomes liquid at or above the melting points of the first and second fluororesin materials (i.e., at or above the higher of the melting points of the first and second fluororesin materials). Furthermore, when the first resin assembly containing the second resin assembly is heated, both the first resin assembly and the second resin assembly are heated as a whole to a temperature above their melting points and melt, integrating the first fluororesin material constituting the first resin assembly with the second fluororesin material constituting the second resin assembly. When this is cooled, the first resin molded body formed from the first fluororesin material and the second resin molded body formed from the second fluororesin material are integrated and molded (hereinafter referred to as "integral melt molding"), producing an integrally joined bonded body. Furthermore, because the first resin molded body and the second resin molded body are integrated and melt molded after being heated as a whole, the occurrence of thermal strain can be suppressed.

[0011] In the above-described method for producing a resin bonded body, the first resin assembly is preferably formed in a cup shape having a recess at an end thereof.

[0012] The first resin assembly may include a cylindrical tubular body, the interior of which serves as the storage portion. In this case, the first resin assembly preferably includes a cylindrical tubular body and a solid rod-like or plate-like body disposed adjacent to the lower part of the tubular body.

[0013] In the above-described method for producing a resin joined body, the first resin aggregate may be a round bar or plate formed from the first fluororesin material, or may be one obtained by cutting these, or may be one obtained by cold compression molding or preforming the first fluororesin material.

[0014] Furthermore, in the method for producing a resin bonded body, the second resin assembly may be formed by molding a second fluororesin material to have a shape and size that can be accommodated in the accommodation portion. In this case, the second resin assembly may be formed by cold compression molding or preforming the second fluororesin material to have a shape and size that can be accommodated in the accommodation portion. Furthermore, the second resin assembly may be made of powder or pellets of the second fluororesin material. Since the second fluororesin material is accommodated and held in the accommodation portion of the first resin assembly, it can be in various forms even if it is a material that melts and becomes liquid when heated to or above its melting point.

[0015] It is preferable that the first fluorine-based resin material is polytetrafluoroethylene (PTFE), and the second fluorine-based resin material is perfluoroalkoxyalkane (PFA).

[0016] In one embodiment, the resin bonded body manufacturing method further includes a diaphragm manufacturing step of manufacturing, from the resin bonded body, a diaphragm for a diaphragm valve, the diaphragm portion having a diaphragm portion and a valve body portion supported at a center of the diaphragm portion so as to move toward and away from a valve seat, and the diaphragm manufacturing step can include the steps of manufacturing a resin bonded body by bonding a first resin molded body and the second resin molded body, cutting a portion of the resin bonded body made of the second resin molded body to form at least a portion of the valve body portion that abuts against the valve seat, and cutting a portion of the resin bonded body made of the first resin molded body to form the diaphragm portion and remaining portions of the valve body portion.

[0017] In the diaphragm manufacturing step, the diaphragm portion, which undergoes repeated deformation, can be formed from PTFE, which has high bending durability, and at least the valve body portion that contacts the valve seat can be formed from PFA, which has low dust-generating properties. Therefore, the bending durability of the diaphragm portion can be ensured while suppressing the generation of particles due to contact and separation between the valve body and the valve seat.

[0018] In another embodiment, the resin bonded body manufacturing method further includes a diaphragm valve manufacturing step of manufacturing, from the resin bonded body, a diaphragm valve including: a valve body in which a first flow path, a second flow path, and a valve chamber in which the first flow path and the second flow path communicate with each other; and a diaphragm having a diaphragm portion and a valve body portion supported at a center of the diaphragm portion, wherein the diaphragm valve manufacturing step can include a step of cutting the resin bonded body to form the first flow path, the second flow path, and the valve chamber from the resin bonded body so that the valve seat is formed in at least the second resin molded body of the resin bonded body.

[0019] In the above diaphragm valve manufacturing step, the valve seat, which is prone to generating particles when it comes into contact with and separates from the valve body, can be made from a second resin molded body made of PFA, which has low dust-generating properties, and the generation of particles due to the contact and separation between the valve body and the valve seat can be suppressed. Also, because the remaining portion of the valve body of the diaphragm valve can be made from PTFE, which is cheaper than PFA, it is possible to reduce the amount of PFA used in the diaphragm valve (more specifically, the valve body) and reduce raw material costs compared to when the entire valve body is made from PFA. [Effects of the Invention]

[0020] According to the present invention, when a first resin assembly containing a second resin assembly housed in a cylindrical housing is heated, both the first resin assembly and the second resin assembly are heated as a whole to a temperature equal to or higher than the melting points of the first and second fluororesin materials, melting and integrating the first and second fluororesin materials constituting the first and second resin assembly. At this time, the first resin assembly gels and maintains its shape, so that the melted, liquid second resin assembly is held within the housing that maintains the cylindrical shape of the first resin assembly and is integrated with the first resin assembly. When this is cooled, the first resin molded body formed from the first fluororesin material and the second resin molded body formed from the second fluororesin material are integrally melt-molded, producing an integrally bonded joined body. Since it is possible to manufacture a joined body by integrally joining molded bodies made of different fluororesin materials through integral melt molding, even when manufacturing a diaphragm from the joined body, it is possible to prevent gaps from forming at the joining surface of the two resin molded bodies even when subjected to an impact when the valve is closed. Furthermore, since the two resin assemblies are heated simultaneously, it is possible to suppress the occurrence of thermal strain and prevent a decrease in the strength of the joining surface between the first resin molded body and the second resin molded body. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view showing the overall configuration of one embodiment of a diaphragm valve including a valve body and a diaphragm made from a resin bonded body produced by the resin bonded body production method of the present invention. [Figure 2] FIG. 1 is an explanatory view for explaining a first embodiment of a method for producing a resin bonded body according to the present invention. [Figure 3] 1 is a cross-sectional view showing a resin bonded body produced by a method for producing a resin bonded body according to the present invention. [Figure 4] FIG. 4 is an explanatory view for explaining a second embodiment of the method for producing a resin bonded body according to the present invention. [Figure 5] FIG. 4 is an explanatory view for explaining a third embodiment of the method for producing a resin bonded body according to the present invention. [Figure 6]FIG. 4 is a cross-sectional view of a resin joined body, with the shape after cutting indicated by a broken line, superimposed on the resin joined body, for illustrating the process of manufacturing the diaphragm of the diaphragm valve shown in FIG. 1 by cutting the resin joined body shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view showing a diaphragm produced by cutting the resin bonded body shown in FIG. 6. [Figure 8] 4 is a cross-sectional view showing a modified form of a diaphragm produced by cutting the resin bonded body shown in FIG. 3. FIG. [Figure 9] FIG. 4 is a cross-sectional view of a resin joined body, with the shape after cutting indicated by a broken line, superimposed on the resin joined body, for illustrating the process of manufacturing the valve body of the diaphragm valve shown in FIG. 1 by cutting the resin joined body shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view showing a valve body produced by cutting the resin bonded body shown in FIG. 9. [Figure 11] FIG. 1 is a cross-sectional view showing a first modified example of a resin bonded body produced by the method for producing a resin bonded body of the present invention. [Figure 12] 12 is a cross-sectional view showing a first modified embodiment of a valve body produced by cutting the resin bonded body of the first modified embodiment shown in FIG. 11. FIG. [Figure 13] FIG. 10 is a cross-sectional view showing a second modified example of a resin bonded body produced by the method for producing a resin bonded body of the present invention. [Figure 14] 14 is a cross-sectional view showing a second modified embodiment of a valve body produced by cutting the resin bonded body of the second modified embodiment shown in FIG. 13. FIG. [Figure 15] 4 is a cross-sectional view showing another modified example of a diaphragm produced by cutting the resin bonded body shown in FIG. 3. FIG. [Figure 16] FIG. 10 is a cross-sectional view showing a third modified example of a resin bonded body produced by the method for producing a resin bonded body of the present invention. [Figure 17] 17 is a cross-sectional view showing a third modified embodiment of a valve body produced by cutting the resin bonded body of the third modified embodiment shown in FIG. 16. FIG. [Figure 18]1 is a cross-sectional view showing a wafer transport box produced by cutting a resin bonded body produced by the resin bonded body production method of the present invention. [Figure 19] 1 is a cross-sectional view showing a tank produced by cutting a resin bonded body produced by the method for producing a resin bonded body of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a method for producing a resin bonded body according to the present invention will be described with reference to the drawings.

[0023] First, the overall configuration of one embodiment of a diaphragm valve using a diaphragm and a valve body made from a resin bonded body produced by the resin bonded body production method according to the present invention will be described with reference to Figure 1. Diaphragm valve 11 includes valve body 13, diaphragm 15, and drive unit 17 that drives diaphragm 15, with drive unit 17 attached to the top of valve body 13.

[0024] The valve body 13 has a valve chamber 19 formed in the center of the upper part, and first and second flow paths communicating with the valve chamber 19. The valve chamber 19 has an annular valve seat 21, to which the diaphragm 15 moves in contact, formed around the opening from the first flow path to the valve chamber 19. In the illustrated embodiment, the first flow path is an inlet flow path 25 that extends from an inlet port 23 formed on one of the opposing side surfaces of the valve body 13 and opens at the center of the bottom of the valve chamber 19, and the second flow path is an outlet flow path 29 that extends from an outlet port 27 formed on the other of the opposing side surfaces of the valve body 13 and opens at a side surface of the valve chamber 19, and the annular valve seat 21 is formed around the opening from the inlet flow path 25 to the valve chamber 19.

[0025] The drive unit 17 includes a drive unit housing 31 attached to the top of the valve body 13 and having a mechanism accommodating space formed therein, a cover member 33 attached to the top of the drive unit housing 31, a stem 35 connected to the diaphragm 15, and a drive mechanism housed in the mechanism accommodating space and driving the stem 35. In this embodiment, a cylinder portion is formed as the mechanism accommodating space inside the drive unit housing 31, and the drive mechanism is composed of a piston 37 housed in the cylinder portion and a coil spring 39 as a biasing member.

[0026] The piston 37 has a piston body 37a slidably accommodated in the cylinder portion of the drive unit housing 31 and a guide shaft 37b extending upward from the piston body 37a, and a stem 35 is connected to the piston body 37a so as to extend downward from the piston body 37a. The stem 35 is slidably inserted into a through-hole provided through the bottom of the drive unit housing 31, and its tip is connected to the diaphragm 15 (more specifically, the valve body 15c described below). The outer peripheral surface of the piston body 37a is in vertical slidable contact with the inner peripheral surface of the cylinder portion, dividing the internal space of the cylinder portion into an upper space 41 surrounded by the top surface of the piston body 37a, the inner peripheral wall of the cylinder portion, and the ceiling surface of the cylinder portion (i.e., the lower surface of the lid member 33), and a lower space 43 surrounded by the bottom surface of the piston body 37a, the inner peripheral wall of the cylinder portion, and the bottom surface of the cylinder portion (i.e., the bottom of the drive unit housing 31). The guide shaft 37b is slidably inserted into a through hole provided through the cover member 33, and guides the piston 37 in its up and down movement.

[0027] A vent hole 45 communicating with the cylinder section that defines the upper space 41 is formed in the cover member 33, and ventilation is possible between the upper space 41 and the outside through the vent hole 45. A working fluid supply port 47 communicating with the bottom of the cylinder section that defines the lower space 43 is formed in the side of the drive unit housing 31, and working fluid can be supplied from the working fluid supply port 47 into the lower space 43. Furthermore, a coil spring 39 is arranged in a compressed state between the lower surface of the cover member 33 (the ceiling surface of the cylinder section) and the upper surface of the piston body 37a.

[0028] The diaphragm 15 includes a diaphragm portion 15b having a base portion 15a protruding downward at its center, a diaphragm portion 15b, and a valve body portion 15c joined to the base portion 15a. The diaphragm portion 15b is formed to extend radially outward from the outer periphery of the upper end of the base portion 15a, and the outer periphery of the diaphragm portion 15b has a roughly circular shape. The outer periphery of the diaphragm portion 15b is sandwiched between the upper surface of the surrounding area of ​​the upper opening of the valve chamber 19 of the valve body 13 and the bottom surface of the drive unit housing 31. The valve body portion 15c has a shape like a truncated cone connected to a cylinder, and is positioned so that its bottom surface (valve seat abutment surface) faces the valve seat 21. The base portion 15a is joined to the valve body portion 15c so that its circumferential surface smoothly connects with the side surface of the truncated cone portion of the valve body portion 15c. In this way, the diaphragm 15 separates the valve chamber 19 from the drive section 17 with the valve body section 15c supported above the valve chamber 19 via the diaphragm section 15b.

[0029] In the illustrated embodiment, a connecting hole 49 is provided that penetrates the base portion 15a of the diaphragm 15 and extends to the valve body portion 15c. The connecting hole 49 includes a small diameter hole portion 49a located closer to the drive portion 17 and a large diameter hole portion 49b located within the valve body portion 15c and provided at the lower end of the connecting hole 49. The distal end (lower end) of the stem 35 is provided with a locking portion 35a that is larger than the intermediate portion, and the diaphragm 15 and the stem 35 are connected by press-fitting the locking portion 35a through the small diameter hole portion 49a into the large diameter hole portion 49b, so that the diaphragm 15 (more specifically, the valve body portion 15c) can move toward and away from the valve seat 21 via the stem 35 as the piston 37 moves up and down. If the stem 35 is connected to the valve body portion 15c as described above, even if the base portion 15a and the valve body portion 15c are separated, it can be prevented from detaching from the diaphragm 15. In the illustrated embodiment, the stem 35 is connected to the valve body portion 15c, but as long as the valve body portion 15c can be moved toward and away from the valve seat 21 by the up and down movement of the piston 37 via the stem 35, the stem 35 may be connected only to the base portion 15a joined to the valve body portion 15c, or may have another configuration.

[0030] In the illustrated embodiment, the valve body 13 includes a first valve body portion 13a in which the valve chamber 19 is formed and a second valve body portion 13b, which is the remaining portion. The first valve body portion 13a is formed from perfluoroalkoxyalkane (PFA), which generates little dust, and the second valve body portion 13b is formed from polytetrafluoroethylene (PTFE), which is less expensive and has higher flexural durability than PFA. Because the valve chamber 19, including the valve seat 21 that contacts and separates from the valve disc portion 15c, is formed from PFA, particle generation due to contact between the valve disc portion 15c and the valve seat 21 can be suppressed. Furthermore, because the second valve body portion 13b is formed from PTFE, which is less expensive than PFA, it is possible to reduce the raw material costs of the valve body 13 while suppressing particle generation, compared to when the entire valve body 13 is formed from PFA. Furthermore, since the diaphragm 15, particularly the diaphragm portion 15b, is subjected to repeated bending, the base portion 15a and the diaphragm portion 15b are made of PTFE, which has high bending durability, while the valve body portion 15c is made of PFA, which has low dust-generating properties, since it is prone to generating particles when it comes into contact with the valve seat 21. The PTFE or PFA used to form the valve body 13 and the diaphragm 15 may be chemically modified or cross-linked by ionizing radiation. Chemically modified PTFE is particularly preferred. The drive unit housing 31, cover member 33, stem 35, and piston 37 of the drive unit 17 may be made of an appropriate material, such as polyvinylidene fluoride (PVDF), PTFE, PFA, or polychlorotrifluoroethylene (PCTFE).

[0031] As described above, in the illustrated embodiment, the valve body 13 and the diaphragm 15 include portions formed from different fluororesin materials, namely, PTFE and PFA. In such cases, the two portions formed from different materials have conventionally been mechanically joined as described in Patent Document 1, welded as described in Patent Document 2, or joined using an adhesive. However, in the case of mechanical joining, in a portion such as the diaphragm 15 (particularly its valve body portion 15c) that is subjected to impact by contacting and separating from the valve seat 21, deformation due to the impact can create gaps at the joint surface between, for example, the base portion 15a and the valve body portion 15c. Liquid in the valve chamber 19 can seep into these gaps, causing material deterioration and making particles more likely to be generated. Furthermore, in the case of welding, for example, only the joint interface between the base portion 15a and the valve body portion 15c is heated and melted using an infrared beam or the like. Therefore, the temperature difference between the melted and unmelted portions causes thermal strain, resulting in a decrease in the strength of the joint interface. Furthermore, when adhesive is used, particularly since the base portion 15a and the valve body portion 15c are placed inside the valve chamber 19, there is a risk that components of the adhesive will dissolve from the bonding interface between the base portion 15a and the valve body portion 15c and mix with the liquid inside the valve chamber 19.

[0032] Therefore, in the present invention, first resin assembly 51 having cylindrical storage portion 51a is made from PTFE, and second resin assembly 53 made of PFA is stored in storage portion 51a of first resin assembly 51, which is heated to a temperature above the melting points of PTFE and PFA (i.e., a temperature above the higher of the melting points of PTFE and PFA) to melt and integrate first resin assembly 51 made of PTFE and second resin assembly 53 made of PFA into a molded body (hereinafter referred to as "integral melt molding"), thereby producing a resin assembly in which the first resin assembly 51 made of PTFE and the second resin assembly 53 made of PFA are integrally joined together, and the produced resin assembly is then cut to produce valve body 13 and diaphragm 15 which include a portion made of PTFE and a portion made of PFA as described above. Heating the first resin aggregate 51 and the second resin aggregate 53 (i.e., the PTFE and PFA that constitute them) to above their melting points does not need to be carried out under pressure, and can be carried out in an unpressurized state (a state in which no particular pressure is applied).

[0033] In this specification, the term "integral melt molding" refers to the melting and integrating of two entire bodies into a single unit, and is used as a different concept from "welding," which melts and joins only the joining surfaces of solidified bodies, and "insert molding," which melts only one of the bodies. Furthermore, in this specification, the term "resin aggregate" refers to a powdered or pelleted resin material formed into a predetermined shape, and includes, for example, a powdered resin material formed by cold compression molding or preforming, or a plate or rod formed from a resin material by compression molding or injection molding and then cutting the powdered or pelleted resin material into a predetermined shape, or a mold filled with a powdered or pelleted resin material, regardless of whether it is in a solid form. Furthermore, the "resin aggregate" does not necessarily have to be formed as a single unit, but may be formed by assembling multiple individual parts.

[0034] A first embodiment of a method for producing a resin joined body, in which a first resin molded body formed from a first fluororesin material and a second resin molded body formed from a second fluororesin material are joined together, will be described in detail below with reference to FIGS. 2 and 3. Hereinafter, an example will be given in which PTFE is used as the first fluororesin material and PFA is used as the second fluororesin material. PTFE and PFA may be chemically modified or crosslinked by ionizing radiation. Chemically modified PTFE is particularly preferred.

[0035] First, a first resin assembly 51 having a cylindrical storage portion 51a is produced from PTFE, a first fluororesin material. In the first embodiment, a cup-shaped first resin assembly 51 having a recess at its upper end that functions as the storage portion 51a, as shown in FIG. 2, is produced. The first resin assembly 51 may be produced by cutting a recess at the upper end of a rod-shaped body or plate compression-molded from PTFE using a mold by a free-baking method, hot-molding method, or the like. Similarly, the first resin assembly 51 may be produced by compression-molding a cup-shaped rod-shaped body or plate having a recess at its upper end using a mold by a free-baking method, hot-molding method, or the like. Furthermore, the first resin assembly 51 does not need to be integrally formed. For example, it may be produced 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 a tubular body and a rod-shaped or plate-shaped body (including a sheet-shaped body) are integrally formed, they may be fabricated separately and then joined by welding. Welding can be performed, for example, by laser welding, hot plate welding, hot air welding, or baking. When the first resin assembly 51 is fabricated from a rod-shaped PTFE body, the PTFE rod-shaped body may be fabricated by extrusion molding. Furthermore, a second resin assembly 53 is fabricated from PFA, a second fluororesin material, having a shape and size that can be accommodated in the accommodation section 51a (recess) of the first resin assembly 51, as shown in FIG. 2 . The second resin assembly 53 is preferably a rod-shaped body whose outer periphery is complementary to the inner circumferential surface of the cylindrical accommodation section 51a. However, since the second resin assembly is liquefied by being heated to or above its melting point and melting, and assumes a shape complementary to the inner circumferential surface of the accommodation section 51a, it is sufficient that the shape and size can be accommodated in the accommodation section 51a. Furthermore, the height of the second resin assembly may be approximately equal to or shorter than the depth of the storage section 51a, as long as the second resin assembly does not overflow from the storage section 51a when heated to or above its melting point and liquefied. The second resin assembly can be produced directly from PFA, for example, by extrusion molding or injection molding using a mold.

[0036] Next, the second resin assembly 53 is accommodated in the accommodation portion 51a (recess) of the first resin assembly 51 and is heated and baked in a baking furnace. The first resin assembly 51 is made of PTFE, and therefore can gel and maintain its cup shape even when heated to above its melting point and melted. On the other hand, the second resin assembly 53 is made of PFA, and therefore can liquefy when heated to above its melting point and melted. However, since the second resin assembly 53 is accommodated in the accommodation portion 51a of the first resin assembly 51, which can gel and maintain its cup shape even when heated to above its melting point and melted, it can remain held within the accommodation portion 51a even when heated to above its melting point and melted into a liquid. This eliminates the need for a mold to maintain contact with the PTFE even when the PFA liquefies, thereby reducing manufacturing costs. The first resin assembly 51 and the second resin assembly 53 are melted and integrally molded by being heated to or above the melting points of the first fluororesin material PTFE and the second fluororesin material PFA (i.e., a temperature above the higher of the melting points of PTFE and PFA), and are integrally bonded to each other. Furthermore, the heating of the first resin assembly 51 and the second resin assembly 53 does not need to be performed under pressure, and can be performed in a pressureless state (a state in which no pressure is particularly applied). Unlike other methods, the generation of distortion and residual stress can be suppressed by integrally melt-molding the first resin assembly 51 and the second resin assembly 53 by heating them in a pressureless state.

[0037] With the second resin assembly 53 accommodated in the accommodation portion 51a (recess) of the first resin assembly 51, the first resin assembly 51 and the second resin assembly 53 are heated in a sintering furnace to above the melting points of PTFE and PFA and then cooled, whereupon, as shown in FIG. 3, the first resin assembly 51 becomes a first resin molded body 55 and the second resin assembly 53 becomes a second resin molded body 57 having a shape roughly complementary to the accommodation portion 51a (recess), resulting in a resin bonded body 59 in which the first resin molded body 55 and the second resin molded body 57 are integrally bonded over the entire contact surface.

[0038] In the resin bonded body 59 manufactured in this manner, the first resin molded body 55 and the second resin molded body 57 are bonded together over the entire contact surface, so that no gap is formed between the first resin molded body 55 and the second resin molded body 57 even when an external force is applied to the resin bonded body 59. Furthermore, because the first resin molded body 55 and the second resin molded body 57 are heated and melted as a whole, no thermal strain occurs, and the strength of the bonded surface between the first resin molded body 55 and the second resin molded body 57 is not reduced due to the occurrence of thermal strain. When a tensile test was performed using a rod-shaped test piece made of the resin bonded body 59 manufactured by the above-described method, it was confirmed that the resin bonded body 59 had sufficient bond strength that the bonded portion between the first resin molded body 55 and the second resin molded body 57 broke at other locations before the bonded portion between the first resin molded body 55 and the second resin molded body 57 and did not peel off.

[0039] In the method for producing a resin joined body 59 obtained by joining a first resin molded body 55 formed from a first fluororesin material and a second resin molded body 57 formed from a second fluororesin material according to the present invention, a first resin assembly 51 having a container 51a is prepared from the first fluororesin material, a second resin assembly 53 made of a second fluororesin material is accommodated in the container 51a (recess) of the first resin assembly 51, and the second fluororesin material of the second resin assembly 53 is held in the container 51a of the first resin assembly 51 that has gelled when heated to a temperature equal to or higher than the melting points of the first and second fluororesin materials. Therefore, the method for producing a resin joined body 59 obtained by joining a first resin molded body 55 formed from PTFE and a second resin molded body 57 formed from PFA is not limited to the first embodiment.

[0040] In the first embodiment, instead of the second resin assembly 53 produced from PFA by a molding method such as extrusion molding or injection molding, PFA powder or pellets filled in the accommodation portion 51a (recess) of the first resin assembly 51 may serve as the second resin assembly 53. Because the first resin assembly 51 is formed in a cup shape, even if the second resin assembly is made of PFA powder or pellets, it can be held within the accommodation portion 51a. Furthermore, when the PFA powder or pellets, which are the second fluororesin material, are heated to or above their melting point in a firing furnace, they melt and liquefy within the accommodation portion 51a of the first resin assembly 51, which maintains its shape even when gelled, similar to the second resin assembly 53 in the resin bonded body manufacturing method according to the first embodiment. Therefore, the PFA, which is the second fluororesin material, is in close contact with the bottom and peripheral surfaces of the accommodation portion 51a of the first resin assembly 51 and is integrated with the PTFE of the gelled first resin assembly 51. By cooling this, it is possible to produce a resin joined body 59 in which a first resin molded body 55 formed from the first resin aggregate 51 and a second resin molded body 57 formed from the second resin aggregate 53 are integrally joined without using a mold, as in the resin joined body production method of the first embodiment. Furthermore, the resin joined body 59 produced by this method can have the same characteristics as the resin joined body 59 produced by the resin joined body production method of the first embodiment.

[0041] Furthermore, as a second embodiment of the method for producing a resin joined body for producing a resin joined body 59 obtained by joining a first resin molded body 55 and a second resin molded body 57, instead of the molded body produced from PTFE powder in the method for producing a resin joined body of the first embodiment, a cup-shaped body having a cylindrical accommodation portion 51a (recess) formed from PTFE powder by cold compression molding may be used as the first resin assembly 51, and instead of the molded body produced from PFA powder in the method for producing a resin joined body of the first embodiment, a body formed from PFA powder by cold compression molding so as to have a shape and size that can be accommodated in the accommodation portion 51a of the first resin assembly 51 may be used as the second resin assembly 53. Note that, as in the first embodiment, the first resin assembly 51 does not need to be configured as an integral body, and may be produced by combining, for example, a cylindrical tubular body and 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, which are separately cold-compression molded. In addition, when the tubular body and the rod-shaped body or plate-shaped body (including sheet-shaped bodies) are integrally formed, they may be produced separately and then joined by welding. Welding can be performed by, for example, laser welding, hot plate welding, hot air welding, baking, etc.

[0042] When the first resin assembly 51 formed by cold compression molding into a cup shape having a cylindrical accommodation portion 51a (recess) at its upper end is heated to above its melting point in a baking furnace, it gels and maintains its cup shape, just like the first resin assembly 51 formed into a cup shape by a molding method such as extrusion molding or injection molding. When the second resin assembly 53 formed by cold compression molding is heated to above its melting point in a baking furnace, it melts and liquefies, just like the second resin assembly 53 formed by a molding method such as extrusion molding or injection molding. Therefore, the PFA, which is the second fluororesin material, is in close contact with the bottom and peripheral surfaces of the accommodation portion 51a of the first resin assembly 51, and is integrated with the PTFE of the gelled first resin assembly 51. By cooling this, it is possible to produce a resin joined body 59 in which a first resin molded body 55 formed from the first resin assembly 51 and a second resin molded body 57 formed from the second resin assembly 53 are integrally joined by integral melt molding, without using a mold, as in the resin joined body production method of the first embodiment. Furthermore, the resin joined body 59 produced by this method can have the same characteristics as the resin joined body 59 produced by the resin joined body production method of the first embodiment.

[0043] 4, in the method for producing a resin bonded body according to the second embodiment, it is preferable to place the first resin assembly 51, with the second resin assembly 53 accommodated in the accommodation portion 51a (recess), in a mold 61, and cover the side of the mold 61 on which the second resin assembly 53 is arranged with a heat insulating material 63. Covering the side on which the second resin assembly 53, made of PFA with a low melting point, with the heat insulating material 63 makes it difficult for heat from the sintering furnace to be transmitted to the second resin assembly 53, and it becomes possible to melt the PTFE forming the first resin assembly 51 and the PFA forming the second resin assembly 53 almost simultaneously.

[0044] In the method for producing a resin joined body according to the second embodiment, instead of the second resin aggregate 53 produced by cold compression molding, PFA powder or pellets filled in the accommodation portion 51a (recess) of the first resin aggregate 51 can be used as the second resin aggregate 53. The time required for melting of the second fluororesin material PFA can be delayed by using pellet-like PFA rather than powder-like PFA.

[0045] Furthermore, as a third embodiment of the method for producing a resin joined body 59 obtained by joining a first resin molded body 55 and a second resin molded body 57, instead of the molded body produced from PTFE powder in the method for producing a resin joined body of the first embodiment, a cup-shaped body formed from PTFE powder by preforming the PTFE powder into a recess that functions as the accommodation portion 51a may be used as the first resin assembly 51, and instead of the molded body produced from PFA powder in the method for producing a resin joined body of the first embodiment, a body preformed from PFA powder so as to have a shape and size that can be accommodated in the accommodation portion 51a of the first resin assembly 51 may be used as the second resin assembly 53, and the resin joined body 59 may be produced by hot molding. In this case, the first resin assembly 51 having the second resin assembly 53 accommodated in the accommodation portion 51a is placed in a mold 61 and heated. As in the first embodiment, the first resin aggregate 51 does not need to be constructed as an integral unit, but may be produced by combining, for example, a cylindrical tubular body and a solid rod-shaped body or plate-shaped body (including a sheet-shaped body) arranged adjacent to the lower part of the cylindrical tubular body and the preformed bodies.

[0046] When heated above its melting point, first resin assembly 51 formed by preforming into a cup shape having a recess at its upper end that functions as storage portion 51a also gels and maintains its cup shape, similar to first resin assembly 51 formed into a cup shape by a molding method such as extrusion molding or injection molding. Similarly, when heated above its melting point, second resin assembly 53 formed by preforming also melts and liquefies, similar to second resin assembly 53 formed by a molding method such as extrusion molding or injection molding. Therefore, PFA, which is the second fluororesin material, is in close contact with the bottom and peripheral surfaces of storage portion 51a of first resin assembly 51, and is integrated with the gelled PTFE of first resin assembly 51. By cooling this, it is possible to produce a resin joined body 59 in which a first resin molded body 55 formed from the first resin aggregate 51 and a second resin molded body 57 formed from the second resin aggregate 53 are integrally joined by integral melt molding, as in the method for producing a resin joined body of the first embodiment. The resin joined body 59 produced by this method can have the same characteristics as the resin joined body 59 produced by the first method for producing a resin joined body.

[0047] 5, in the resin bonded body manufacturing method of the third embodiment, the first resin assembly 51, with the second resin assembly 53 accommodated in the accommodation portion 51a (recess), is placed in a mold 61, and the area around the second resin assembly 53 in the mold 61 is preferably heated by a first band heater 65, and the area below the second resin assembly 53 is heated by a second band heater 67. By using different band heaters 65 and 67, the heating temperature of the first band heater 65, which heats the area where the second resin assembly 53 made of PFA, which has a relatively low melting point, is placed, can be set lower than the heating temperature of the second band heater 67, which heats the area where only the first resin assembly 51 made of PTFE, which has a relatively high melting point, is placed. This makes it possible to melt the PTFE that forms the first resin assembly 51 and the PFA of the second resin assembly 53 almost simultaneously. The first band heater 65 and the second band heater 67 may be any heater capable of heating the mold, and other heating devices such as rod heaters may be used instead.

[0048] In the method for producing a resin bonded body according to the third embodiment, instead of the second resin aggregate 53 produced by preforming, PFA powder or pellets filled in the accommodation portion 51a (recess) of the first resin aggregate 51 may be used as the second resin aggregate 53. PFA in pellet form can melt more slowly than PFA in powder form.

[0049] The resin bonded body 59 thus produced can be used as an intermediate material for various parts. A method for manufacturing parts of the diaphragm valve 11 from the resin bonded body 59 will be described below as an example.

[0050] FIG. 6 shows a method for producing a diaphragm 15 from a resin bonded body 59. A diaphragm 15 as shown in FIG. 7 can be produced by cutting the resin bonded body 59 as indicated by the dashed line in FIG. 6. The diaphragm 15 shown in FIG. 7 is used in the diaphragm valve 11 shown in FIG. 1. In the diaphragm 15, the diaphragm portion 15b having the base portion 15a at its center is made of a first resin molded body 55 formed from a first fluororesin material in the resin bonded body 59, i.e., made from PTFE, which has high flexural durability. Furthermore, the valve body portion 15c of the diaphragm 15 is made of a second resin molded body 57 formed from a second fluororesin material in the resin bonded body 59, i.e., made from PFA, which has low dust generation properties. Because the first resin molded body 55 and the second resin molded body 57 of the resin bonded body 59 are integrally bonded by integral melt molding, the boundary surface (bonding surface) between the base portion 15a and the valve body portion 15c of the diaphragm 15 is also integrally bonded. Therefore, even if the valve body portion 15c abuts against the valve seat 21 and is deformed by impact when the valve is closed, no gap is generated at the boundary surface between the base portion 15a and the valve body portion 15c, and a decrease in strength due to liquid in the valve chamber 19 entering the gap can be prevented. Furthermore, because both the first resin assembly 51 and the second resin assembly 53 are heated and then cooled overall, the occurrence of thermal strain is suppressed, and a decrease in strength due to thermal strain can also be suppressed.

[0051] 6, it is also possible to form only the vicinity of the valve seat abutment surface that abuts against the valve seat 21 from the second resin molded body 57 of the resin joined body 59, and only the vicinity of the abutment surface against the valve seat 21 from PFA, which has low dust-generating properties, as in the diaphragm 15' shown in FIG. 8. In this case, the connecting hole 49 is provided only in the base portion 15a. The first resin molded body 55 and the second resin molded body 57 of the resin joined body 59 are integrally melt-molded, and the base portion 15a and the valve body portion 15c made from these are integrally formed. Therefore, as the stem 35 moves up and down, the valve body portion 15c moves in conjunction with the base portion 15a, and can move toward and away from the valve seat 21.

[0052] FIG. 9 shows a method for producing a valve body 13 from a resin bonded body 59. The valve body 13 shown in FIG. 10 can be produced by cutting the resin bonded body 59 as indicated by the dashed line in FIG. 9. The valve body 13 shown in FIG. 10 is used in the diaphragm valve 11 shown in FIG. 1. In the valve body 13, the first valve body portion 13a, in which the valve chamber 19 is formed, is made from a second resin-molded body 57 formed from a second fluororesin material in the resin bonded body 59, i.e., PFA, which has low dust-generating properties. The second valve body portion 13b, in which the inlet 23 and outlet 27 of the valve body 13 are formed, is made from a first resin-molded body 55 formed from a first fluororesin material in the resin bonded body 59, i.e., PTFE, which is less expensive than PFA. The inlet flow path 25 and the outlet flow path 29 are provided so as to straddle the first valve body portion 13a and the second valve body portion 13b, extending from the inlet 23 and the outlet 27 to the valve chamber 19. The valve seat 21 provided on the first valve body portion 13a is formed of PFA, which has low dust-generating properties. Therefore, even if the valve disc portion 15c abuts against the valve seat 21 when the valve is opened or closed, the generation of particles can be suppressed, and contamination of the liquid in the valve chamber 19 by generated particles can be reduced. Furthermore, the first valve body portion 13a is made from the second resin molded body 57 formed from the relatively expensive PFA, and the second valve body portion 13b of the valve body 13 is made from the first resin molded body 55 formed from the relatively inexpensive PTFE. Therefore, compared to when both the first valve body portion 13a and the second valve body portion 13b of the valve body 13 are made from PFA, it is possible to reduce the raw material costs of the valve body 13 while suppressing the generation of particles caused by the valve body portion 15c abutting against the valve seat 21.

[0053] Alternatively, a third resin assembly made of a third fluororesin material may be placed on top of second resin assembly 53 placed in accommodation portion 51a (recess) of first resin assembly 51, and the resulting assembly may be heated to or above its melting point and then cooled to produce resin joined body 59' in which a first resin molded body made of the first fluororesin material, a third resin molded body 69 made of the third fluororesin material, and a second resin molded body made of the second fluororesin material are sandwiched between them and joined together by integral melt molding, as shown in Fig. 11. By using PTFE as the first and third fluororesin materials and PFA as the second fluororesin material and performing cutting as indicated by the dashed line in Fig. 11, a valve body 13' as shown in Fig. 12 can be produced.

[0054] The valve body 13' includes a second valve body portion 13b made from a first resin molded body 55 formed from a first fluororesin material, a first valve body portion 13a made from a second resin molded body 57 formed from a second fluororesin material, and a third valve body portion 13c made from a third resin molded body 69 formed from a third fluororesin material. The valve chamber 19 is formed across the first valve body portion 13a and the third valve body portion 13c so that the valve seat 21 is made from the second resin molded body 57. The inlet 23 and outlet 27 of the valve body 13 are provided in the second valve body portion 13b made from the first resin molded body 55, and the inlet flow path 25 and outlet flow path 29 extend from the inlet 23 and outlet 27 to the valve chamber 19, straddling the second valve body portion 13b made from the first resin molded body 55 of the resin joined body 59 and the first valve body portion 13a made from the second resin molded body 57. In this valve body 13', only a portion of the valve chamber 19, including the valve seat 21 with which the valve disc portion 15c comes into contact when the valve is opened or closed, is made of PFA, which is low in dust generation but relatively expensive. This suppresses the generation of particles due to the impact when the valve disc portion 15c comes into contact with the valve seat 21 when the valve is closed, while also achieving even lower raw material costs than the valve body 13 shown in FIG. 10.

[0055] Furthermore, by disposing second resin assembly 53, which has a smaller volume than that of accommodation portion 51a (recess) of first resin assembly 51, in the recess, and heating the resulting assembly to or above the melting points of the first and second fluororesin materials (i.e., to a temperature equal to or higher than the higher of the melting points of the first and second fluororesin materials), and then cooling it, it is possible to produce a resin joined body 59″ as shown in FIG. 13, in which only a portion of accommodation portion 51a is filled with a second resin-molded body made of the second fluororesin material and the two bodies are integrally joined together by integral melt molding. By using PTFE as the first fluororesin material and PFA as the second fluororesin material and performing cutting as indicated by the dashed line in FIG. 13, a valve body 13″ as shown in FIG. 14 can be produced. In the valve body 13", only the portion of the valve chest 19 that forms the valve seat 21 is the first valve body portion 13a made of a second resin molded body 57 made of the second fluororesin material, and the remaining portion is the second valve body portion 13b made of a first resin molded body 55 made of the first fluororesin material. Only the portion of the valve chest 19 that forms the valve seat 21 with which the valve disc portion 15c comes into contact and separates when the valve is opened and closed is made of PFA, which has low dust-generating properties but is relatively expensive. This suppresses the generation of particles due to the impact when the valve disc portion 15c comes into contact with the valve seat 21 when the valve is closed, while also reducing raw material costs compared to the valve body 13 shown in FIG. 12. Furthermore, because the space portion of the valve chest 19 overlaps with the portion of the accommodation portion 51a that is not used as the second resin molded body, the amount of unnecessary cutting can be reduced, and raw material costs can be suppressed.

[0056] The above describes a method for producing the diaphragms 15, 15' and valve bodies 13, 13, 13" of the diaphragm valve 11 from the resin joined bodies 59, 59', 59" produced by the method for producing a resin joined body of the present invention. However, even if a valve body or valve element portion of another type of valve, such as a constant pressure valve or a flow control valve, is produced from a resin joined body produced by the method for producing a resin joined body of the present invention, the same effects as those of the diaphragm 15, 15' and valve bodies 13, 13, 13" of the diaphragm valve 11 produced as described above can be achieved.

[0057] Next, referring to FIG. 1, the operation of the diaphragm valve 11 will be described. As shown in FIG. 1, under normal conditions when no working fluid is supplied to the actuator 17 from the working fluid supply port 47, the piston 37 of the actuator 17 is pushed downward by the coil spring 39. As a result, the valve body 15c moves toward the valve seat 21 via the stem 35 and is pressed against the valve seat 21, placing the diaphragm valve 11 in the closed state as shown in FIG. 1. Accordingly, the diaphragm 15b, which supports the valve body 15c via the base 15a, also deforms away from the actuator 17. When working fluid is supplied to the working fluid supply port 47 of the actuator 17 from this state, the fluid pressure of the working fluid that has flowed into the lower space 43 of the cylinder acts upward on the piston body 37a, pushing the piston 37 up against the biasing force of the coil spring 39. At this time, air in the upper space 41 is released to the outside through the vent 45. As a result, the valve body portion 15c is moved away from the valve seat 21 via the stem 35, and the diaphragm valve 11 is placed in the open state. Accordingly, the diaphragm portion 15b is also deformed in the direction approaching the drive portion 17. When the supply of working fluid to the working fluid supply port 47 is stopped, the piston 37 is again urged downward by the coil spring 39 and pressed down, so that the valve body portion 15c is pressed against the valve seat 21, and the valve is placed in the closed state again.

[0058] As described above, in the diaphragm valve 11, the valve element 15c repeatedly moves toward and away from the valve seat 21, and particularly when the valve element 15c abuts against the valve seat 21, impact is likely to generate particles. However, in the diaphragm valve 11, the valve element 15c that abuts against the valve seat 21 is formed from PFA, which has low dust-generating properties, so that generation of particles from the valve element 15c can be suppressed. Similarly, the first valve body portion 13a of the valve body 13, in which the valve chamber 19 is formed, is also formed from PFA, which has low dust-generating properties, so that generation of particles from the valve seat 21 can be suppressed. In addition, the intermediate material of the diaphragm 15 is produced as a resin bonded body 59 in which both the first resin molded body 55 made of PTFE and the second resin molded body 57 made of PFA are heated and melted throughout, and the first resin molded body 55 and the second resin molded body 57 are integrally bonded to each other by integral melt molding. Therefore, even if the disc portion 15c abuts against the valve seat 21 and is deformed by the impact, no gap is formed between the disc portion 15c and the base portion 15a, and no thermal strain occurs, preventing a decrease in strength due to heating in both the valve body 13 and the diaphragm 15. Furthermore, since the second valve body portion 13b other than the first valve body portion 13a that repeatedly comes into and out of contact with the disc portion 15c is made of PTFE, which is a cheaper material than PFA, an increase in the manufacturing cost of the valve body 13 can be suppressed compared to when the entire valve body 13 is manufactured from PFA. Such effects can be similarly obtained when the resin joined body according to the present invention is applied to a constant pressure valve or a flow control valve that includes a valve body having a base portion, a disc portion, and a valve seat where the disc portion comes into and out of contact with each other, in addition to an on-off valve such as the diaphragm valve 11 described above.

[0059] The method for producing a resin bonded body according to the present invention and the method for producing a diaphragm 15 for a diaphragm valve from a resin bonded body 59 produced by the resin bonded body production method and a diaphragm valve 11 using the diaphragm 15 have been described above with reference to the illustrated embodiments. However, the present invention is not limited to the illustrated embodiments. For example, the above description uses PTFE as the first fluororesin material and PFA as the second fluororesin material. However, the first fluororesin material and the second fluororesin material are not limited to PTFE and PFA as long as the first fluororesin material can gel and maintain its shape even when melted when heated above its melting point, and the second fluororesin material can melt and liquefy when heated above its melting point. For example, ethylene tetrafluoroethylene copolymer (ETFE), perfluoroethylene propene copolymer (FEP), polyvinylidene fluoride (PVDF), or the like may be used as the second fluororesin material instead of PTFE. Furthermore, in the method for producing a resin bonded body according to the present invention, it is only necessary that the accommodation portion 51a be capable of accommodating the second resin assembly 53. The bottom of the cylindrically formed first resin assembly 51 may be placed on a mold, and the bottom of the internal space of the cylindrical first resin assembly 51 may be closed with the mold to form a recess that functions as the accommodation portion 51a, and the second resin assembly 53 may be accommodated in the recess thus formed. In this case, the mold is preferably tub-shaped or dish-shaped.

[0060] Furthermore, by cutting out a part made from the resin bonded body 59 from an appropriate position, it is possible to change which area of ​​the part is made from a different fluororesin material. For example, by changing the cutting position from the resin bonded body 59, it is possible to make only a part of the valve seat abutment surface of the diaphragm 15" made from the second resin molded body 57, as in the diaphragm 15 shown in Figure 7 or the diaphragm 15' shown in Figure 8, rather than making the entire valve seat abutment surface that abuts against the valve seat 21 in the valve body portion 15c of the diaphragm 15 or 15' made from the second resin molded body 57 made from the low-dust-generating PFA.

[0061] Furthermore, depending on the location of the portions desired to be formed from different fluororesin materials, the number of accommodation portions 51a of the first resin assembly 51 and the volume of the second resin assembly 53 to be placed in each accommodation portion 51a may be changed to manufacture the resin joined body 59. For example, by forming three accommodation portions 51a in the first resin assembly 51 and using PTFE as the first fluororesin material and PFA as the second fluororesin material, a resin joined body 159 is manufactured in which second resin molded bodies 157A, 157B, and 157C made of the second fluororesin material are formed at separate positions within a first resin molded body 155 made of the first fluororesin material, as shown in Fig. 16. This resin joined body 159 is then cut as indicated by the dashed line in Fig. 16 to manufacture a valve body 113 as shown in Fig. 17. In the valve body 113, only the portion of the valve chamber 19 that forms the valve seat 21, the inlet fitting where the inlet port 23 connected to the inlet flow path 25 is formed, and the outlet fitting where the outlet port 27 connected to the outlet flow path 29 is formed are made into a first valve body portion 13a made of a second resin molded body 57 made of a second fluororesin material, and the remaining portion is made into a second valve body portion 13b made of a first resin molded body 55 made of a first fluororesin material. By forming only the portion of the valve chamber 19 that forms the valve seat 21 with which the valve disc portion 15c comes into and out of PFA, which has low dust generation and high abrasion resistance but is relatively expensive, it is possible to suppress the generation of particles due to the impact when the valve disc portion 15c comes into contact with the valve seat when the valve is closed, and to suppress wear of the fitting when the tube is connected.

[0062] Additionally, while the above description exemplifies the fabrication of a component of a diaphragm valve 11 from a resin bonded body 59 manufactured according to the present invention, the component manufactured from the resin bonded body 59 manufactured according to the present invention is not limited to a component of a diaphragm valve, and may be a component of other types of valves or other types of components. For example, as shown in FIG. 18 , by changing the shape of the second resin molded body 57 and using PTFE as the first fluororesin material and PFA as the second fluororesin material to manufacture the resin bonded body 59, it is possible to fabricate a wafer transport box (so-called FOUP) 201 having a first portion 203 located on the inner surface and made of PFA and a second portion 205 located on the outer surface and made of PTFE. In the wafer transport box 201, the inner surface that comes into contact with the wafer is made of highly abrasion-resistant PFA, thereby suppressing wear. 19, by producing a resin joint body 59 using PTFE as the first fluororesin material and PFA as the second fluororesin material, it is possible to produce a tank 301 having an inner layer 303 located on the inner surface side and made of PFA, and an outer layer 305 located on the outer surface side and made of PTFE. In addition, it is possible to produce a pump, a nozzle, a pressure sensor, etc. from the resin joint body 59 produced according to the present invention. [Explanation of symbols]

[0063] 11 Diaphragm valve 13 Valve body 13' Valve body 13" valve body 13a First valve body portion 13b second valve body portion 13c Third valve body portion 15 diaphragm 15' diaphragm 15" diaphragm 15a Base part 15b Diaphragm part 15c Valve body 19 Valve chamber 21 Valve seat 25 Inlet channel 29 Outlet flow path 51 First resin assembly 51a Storage section 53 Second resin assembly 55 First resin molding 57 Second resin molding 59 Resin joint 59' Resin joint 59" Resin joint 113 Valve body 155 First resin molding 157A Second resin molding 157B Second resin molding 157C Second resin molding 159 Resin joints 201 Wafer transport box 203 First Part 205 Second Part 301 Tank 303 Inner layer 305 Outer layer

Claims

1. 1. A method for producing a resin joined body by joining two resin molded bodies formed from different fluorine-based resin materials, comprising: forming a first resin assembly having a cylindrical containing portion from a first fluororesin material that can maintain its shape by gelling even when the temperature is equal to or higher than the melting point; a step of accommodating a second resin assembly made of a second fluororesin material that melts and becomes liquid when the temperature reaches or exceeds its melting point in the accommodating portion; heating the first resin assembly containing the second resin assembly in the housing portion to a temperature equal to or higher than the melting points of the first fluororesin material and the second fluororesin material, and then cooling the first resin assembly to transform it into a first resin molded body and the second resin assembly into a second resin molded body, and bonding the first resin molded body and the second resin molded body together; A method for producing a resin bonded body, comprising:

2. The method for producing a resin joined body according to claim 1 , wherein the first resin aggregate is formed into a cup shape having a recess at an end thereof.

3. The method for producing a resin joined body according to claim 1 , wherein the first resin assembly includes a cylindrical tubular body, and the inside of the tubular body serves as the container portion.

4. 4. The method for producing a resin joined body according to claim 3, wherein the first resin assembly comprises a cylindrical tubular body and a solid rod-like or plate-like body disposed adjacent to the lower part of the tubular body.

5. 2. The method for producing a resin joined body according to claim 1, wherein the first resin assembly is a round bar or plate molded from the first fluororesin material, or one obtained by cutting such a bar or plate.

6. 2. The method for producing a resin joined body according to claim 1, wherein the first resin aggregate is formed by cold compression molding or preforming the first fluororesin material.

7. 6. The method for producing a resin joined body according to claim 5, wherein the second resin assembly is formed from a second fluororesin material so as to have a shape and size that can be accommodated in the accommodation portion.

8. 7. The method for producing a resin joined body according to claim 6, wherein the second resin assembly is formed from a second fluororesin material so as to have a shape and size that can be accommodated in the accommodation portion.

9. 8. The method for producing a resin joined body according to claim 7, wherein the second resin assembly is formed by cold compression molding or preforming the second fluororesin material so as to have a shape and size that can be accommodated in the accommodation portion.

10. 9. The method for producing a resin joined body according to claim 8, wherein the second resin assembly is formed by cold compression molding or preforming the second fluororesin material so as to have a shape and size that can be accommodated in the accommodation portion.

11. 6. The method for producing a resin joined body according to claim 5, wherein the second resin aggregate is made of powder or pellets of the second fluororesin material.

12. 7. The method for producing a resin joined body according to claim 6, wherein the second resin aggregate is made of powder or pellets of the second fluororesin material.

13. a diaphragm manufacturing step of manufacturing a diaphragm for a diaphragm valve from the resin bonded body, the diaphragm having a diaphragm portion and a valve body portion supported at the center of the diaphragm portion so as to come into contact with and separate from a valve seat, The diaphragm manufacturing step a step of cutting a portion of the resin joined body that is configured by the second resin molded body to form at least a portion of the valve body that abuts against the valve seat; cutting a portion of the resin joined body that is formed by the first resin molded body to form the diaphragm portion and the remaining portions of the valve body portion; The method for producing a resin bonded body according to claim 1 , comprising:

14. a diaphragm valve manufacturing step of manufacturing, from the resin bonded body, a diaphragm valve including a valve body formed with a first flow path, a second flow path, and a valve chamber to which the first flow path and the second flow path communicate, and a diaphragm having a diaphragm portion and a valve body portion supported at a center of the diaphragm portion, 2. The resin bonded body manufacturing method according to claim 1, wherein the diaphragm valve manufacturing step includes a step of cutting the resin bonded body to form the first flow path, the second flow path, and the valve chamber from the resin bonded body so that the valve seat is formed at least in the second resin molded body of the resin bonded body.

15. 15. The method for producing a resin joined body according to claim 1, wherein the first fluorine-based resin material is polytetrafluoroethylene (PTFE), and the second fluorine-based resin material is perfluoroalkoxyalkane (PFA).

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