Manufacturing method for fluororesin molded products

Abstract

To provide a fluororesin molded article having a low particle property and excellent high temperature durability, and a method for manufacturing the same.SOLUTION: A method for manufacturing a fluororesin molded article includes: inserting one part of a placing piece into a hole provided in a reinforcing material; holding the reinforcing material in a cavity defined between a movable-side mold and a stationary-side mold by fixing the other part of the placing piece protruded from the reinforcing material removably to the movable-side mold side; after flowing a first fluororesin being a meltable fluororesin into the cavity, cooling the first fluororesin to form a primary molded article; taking out the primary molded article with the placing piece; removing the placing piece from the hole of the reinforcing material to obtain the primary molded article having a space portion corresponding to the placing piece; and sealing the space portion of the primary molded article with a second fluororesin.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fluororesin molded article and a method for producing the same. [Background technology]

[0002] Fluorine resins such as polytetrafluoroethylene (PTFE) are resistant to chemicals and heat, and as a result, among the molded products obtained from PTFE, one-piece tanks such as square tanks are used in the chemical cleaning process for semiconductors and liquid crystals, and round ones such as ring-shaped ones are used as cups for cleaning silicon wafers one by one.

[0003] Molded products made of PTFE have the characteristic that residual stress is likely to remain inside, and therefore warping and bending easily occur. For this reason, as disclosed in Patent Document 1, fluororesin molded products made of PTFE with reinforcing material embedded inside have been used. Molded products with reinforcing material embedded can suppress deformation even in high temperature environments.

[0004] However, since fluororesin molded products made by compression molding PTFE are essentially made by sintering powder, they tend to have lower particle generation properties compared to molded products made of molten fluororesin. On the other hand, with the recent trend toward finer semiconductors, cleaning equipment used for cleaning is required to have an extremely high level of low particle generation properties, and the chemicals used to remove particles are also becoming hotter. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2011-020304 A Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fluororesin molded article having low particle generation and excellent high-temperature durability, and a method for producing the same. [Means for solving the problem]

[0007] According to a first aspect of the present invention, there is provided a method for manufacturing a fluororesin molded product. The method for manufacturing a fluororesin molded product includes inserting a part of a placing piece into a hole provided in a reinforcing material, heating a movable mold and a fixed mold, holding the reinforcing material in a cavity defined between the movable mold and the fixed mold by removably fixing another part of the placing piece protruding from the reinforcing material to the movable mold side, closing the movable mold and the fixed mold, flowing a first fluororesin, which is a molten fluororesin, into the cavity, and then cooling the first fluororesin to form a primary molded product, opening the movable mold and the fixed mold, and taking out the primary molded product together with the placing piece, removing the placing piece from the hole in the reinforcing material to obtain a primary molded product having a space portion corresponding to the placing piece, and sealing the space portion of the primary molded product with a second fluororesin. Effect of the Invention

[0009] According to the present invention, it is possible to provide a fluororesin molded article having low particle generation and excellent high-temperature durability, and a method for producing the same. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a cross-sectional view showing a state in which a fixed mold and a movable mold of the injection molding die according to the embodiment are being opened. [Diagram 2] FIG. 2 is a cross-sectional view showing a state in which a fixed mold and a movable mold of the injection molding die according to the embodiment are closed. [Diagram 3] FIG. 2 is a partially exploded perspective view showing a step in the manufacture of a fluororesin molded article according to the embodiment. [Figure 4] FIG. 3 is a partially cutaway cross-sectional view showing a step in the manufacture of a fluororesin molded article according to the embodiment. [Diagram 5] 1 is a cross-sectional view illustrating a process for producing a fluororesin molded article according to an embodiment of the present invention. [Figure 6] 3A and 3B are a top view and a side view, respectively, which illustrate schematic examples of shapes of plugs used in one step of the production of a fluororesin molded product according to the embodiment. [Figure 7] 1 is a cross-sectional view illustrating a process for producing a fluororesin molded article according to an embodiment of the present invention. [Figure 8] 1 is a cross-sectional view illustrating a process for producing a fluororesin molded article according to an embodiment of the present invention. [Figure 9] FIG. 1 is a perspective view showing a schematic diagram of a rectangular tank as a fluororesin molded product according to one embodiment. [Figure 10] 10 is a schematic cross-sectional view taken along line XX of the rectangular tank shown in FIG. 9. [Figure 11] 10 is a schematic cross-sectional view taken along line XI-XI of the rectangular tank shown in FIG. 9. [Figure 12] FIG. 10 is a plan view showing a schematic view of the upper surface of the rectangular tank shown in FIG. [Figure 13] FIG. 2 is a top view showing a schematic diagram of a cup for a single wafer cleaning apparatus as a fluororesin molded product according to one embodiment. [Figure 14] 14 is a schematic cross-sectional view taken along line XIV-XIV of the rectangular tank shown in FIG. 13. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments will be described with reference to the drawings as appropriate. Note that the same reference numerals are used to designate common components throughout the embodiments, and duplicated descriptions will be omitted. Also, each figure is a schematic diagram for explaining the embodiments and for facilitating understanding thereof, and the shapes, dimensions, ratios, etc. may differ from those of the actual device, but these can be appropriately modified in design by taking into consideration the following explanation and known techniques. (First embodiment) The method for producing a fluororesin molded article according to the first embodiment will be described below with reference to FIGS.

[0012] 1 and 2 show an injection molding die 100 capable of manufacturing a fluororesin molded product by injection molding. The injection molding die 100 comprises a fixed die 20 and a movable die 40. FIG. 1 shows a state in which the fixed die 20 and the movable die 40 are opening. FIG. 2 shows a state in which the fixed die 20 and the movable die 40 are closing. The movable die 40 is configured to be movable in a direction approaching and moving away from the fixed die 20. A cavity 50 is defined between the fixed die 20 and the movable die 40. The cavity 50 is a hollow portion.

[0013] The movable side mold 40 includes a movable side mounting plate 41, spacer blocks 42a and 42b, a movable side mold plate 43, an ejector plate 44, and ejector pins 45a and 45b. The spacer blocks 42a and 42b are fixed to the movable side mounting plate 41. The movable side mold plate 43 is fixed to the spacer blocks 42a and 42b. The ejector plate 44 is attached to the movable side mounting plate 41. The ejector pins 45a and 45b are fixed to the ejector plate 44. The movable side mold plate 43 includes a protrusion 430 as a core. The movable side mold plate 43 is provided with through holes 46a and 46b along the direction in which the movable side mold 40 can move. The ejector pin 45 extends from the ejector plate 44 and is inserted into the through holes 46a and 46b. The ejector pin 45 is configured to be able to eject a molded product formed in the cavity 50 after injection molding. Although the number of ejector pins is two here as an example, the number of ejector pins may be one or more than two.

[0014] The fixed-side mold 20 includes a fixed-side attachment plate 21, a fixed-side mold plate 22, a sprue 23, and a gate 24. The fixed-side mold plate 22 is fixed to the fixed-side attachment plate 21. The fixed-side mold plate 22 has a recess 220. When the fixed-side mold 20 and the movable-side mold 40 are closed, a cavity 50 corresponding to the shapes of the recess 220 of the fixed-side mold plate 22 and the protrusion 430 of the movable-side mold plate 43 is defined between them.

[0015] The movable-side mold plate 43 has a movable-side first surface 43a that contacts the fixed-side mold plate 22. The fixed-side mold plate 22 has a fixed-side first surface 22a that contacts the movable-side mold plate 43. When the fixed-side mold 20 and the movable-side mold 40 are closed, the surface where the movable-side first surface 43a and the fixed-side first surface 22a contact is called a parting line PL.

[0016] The sprue 23 is a through hole that penetrates the fixed-side mounting plate 21 and the fixed-side mold plate 22. The gate 24 is an opening at the boundary between the fixed-side mold plate 22 and its recess 220. Here, the case where the gate 24 is a direct gate is shown, but the fixed-side mold 20 may also be provided with, for example, a separate runner. The configuration of the sprue, runner, gate, etc. in the fixed-side mold can be appropriately changed depending on the shape of the desired fluororesin molded product.

[0017] A piece mount portion 47a is provided in a part of the through hole 46a of the movable-side mold plate 43. Similarly, a piece mount portion 47b is provided in a part of the through hole 46b. The piece mounting parts 47a and 47b may be through holes that are continuous with the through holes 46a and 46b, as shown in Fig. 3, which will be described later. The piece mounting parts 47a and 47b define a space having a semi-conical shape that expands in diameter in an inverse tapered manner from a certain portion of the through holes 46a and 46b to the movable-side first surface 43a (parting line PL). Note that the shape of the piece mounting parts is one example, and the shape is not limited as long as it does not impair the function of the piece, which will be described later.

[0018] The method for producing a fluororesin molded article according to the embodiment is carried out, for example, as follows, using the above-mentioned injection molding die 100. The method for producing a fluororesin molded article will be further described with reference to Fig. 3 to Fig. 8. Fig. 3 is a partially exploded perspective view showing one step in the production of a fluororesin molded article according to the embodiment.

[0019] 3, a part of the placement piece 31a and a part of the placement piece 31b are inserted into the through holes 6a and 6b, respectively, provided in the reinforcing material 6. The through holes 6a and 6b may be holes that do not penetrate the reinforcing material 6.

[0020] The reinforcing material 6 is a component that can be contained in the final fluororesin molded product. By containing the reinforcing material 6 inside the fluororesin molded product, deformation such as warping and bending of the fluororesin molded product can be suppressed. It is preferable that the entire reinforcing material 6 is embedded in the fluororesin molded product, but a part of the reinforcing material 6 may be exposed.

[0021] The shape of the reinforcing material 6 is not particularly limited, and may be, for example, plate-like or rod-like. The reinforcing material 6 has at least one hole into which a part of the placing piece 31 can be inserted. The number of placing pieces 31 held in the cavity 50 is not particularly limited, and may be one or more. Therefore, the number of reinforcing materials contained in the fluororesin molded product may be one or more. The material of the reinforcing material 6 may be, for example, at least one selected from the group consisting of metal, ceramic, and resin. A single fluororesin molded product may have multiple types of reinforcing materials 6 that are different from each other in material and / or shape.

[0022] The insert 31 is used to hold the reinforcing material 6 in the cavity 50 during injection molding. The above-mentioned Figs. 1 and 2 show an example of a state in which the reinforcing material 6 is held in the cavity 50. For example, as shown in Fig. 3, the insert 31 is, for example, a male screw having a male screw portion. Specifically, the insert 31 has a head portion 310, a shaft portion 311, and a male screw portion 312. Meanwhile, the inner walls of the through holes 6a and 6b of the reinforcing material 6 form female screw portions. Therefore, the male screw portions of the insert 31 can be screwed into the through holes 6a and 6b of the reinforcing material 6.

[0023] A part of the piece 31a (here, the male screw portion 312a) is inserted into the through hole 6a of the reinforcing material 6, thereby fixing the piece 31a to the reinforcing material 6. Similarly, a part of the piece 31b (here, the male screw portion 312b) is inserted into the through hole 6b of the reinforcing material 6, thereby fixing the piece 31b to the reinforcing material 6. The other part of the piece 31a, i.e., the head 310a and the shaft 311a, protrudes from the reinforcing material 6. The other part of the piece 31b, i.e., the head 310b and the shaft 311b, protrudes from the reinforcing material 6. If the length (length perpendicular to the radial direction) of the shaft 311 of the piece 31 is too small, it is not preferable because the molten first fluororesin may not easily flow between the reinforcing material 6 and the movable-side mold plate 43 during injection molding.

[0024] In this embodiment, the case where the base 31 is a male thread as described above is described as an example, however, bases having other configurations may be used as long as they can hold the reinforcing material 6 within the cavity 50 during injection molding.

[0025] Next, the movable mold 40 and the fixed mold 20 are preheated. In particular, the movable mold plate 43 and the fixed mold plate 22 are heated. Typically, the preheating is performed in a state where the movable mold 40 and the fixed mold 20 are closed. The temperatures of the movable mold plate 43 and the fixed mold plate 22 can be appropriately set depending on the composition of the fluororesin to be poured, but are set within a range of 180°C to 200°C, for example.

[0026] Next, the other part of the piece 31a and the other part of the piece 31b protruding from the reinforcing material 6 are attached to the piece attachment parts 47a and 47b provided on the movable side mold plate 43. However, this attachment is performed so that the piece 31 can be protruded together with the reinforcing material 6 by the protruding action of the ejector pins 45a and 45b in a process after the injection molding. Specifically, of the head part 310a and the shaft part 311a of the piece 31 protruding from the reinforcing material 6, only the head part 310a is fitted into the piece attachment part 47. The head part 310a has a shape corresponding to the space defined by the piece attachment part 47, for example. Since the head part 310a is merely fitted into the piece attachment part 47, the piece 31 can be pushed out of the piece attachment part 47 by the protruding action of the ejector pins 45a and 45b. In other words, the other part of the piece 31 protruding from the reinforcing material 6 is fixed to the movable side mold plate 43 in a removable state, thereby holding the reinforcing material 6 within the cavity 50.

[0027] Next, the movable mold 40 is moved in a direction approaching the fixed mold 20. The movable first surface 43a and the fixed first surface 22a are brought into contact with each other, thereby closing the molds. Then, a first fluororesin, which is a melt-type fluororesin, is poured into the sprue 23 from an injection molding machine (not shown). The first fluororesin is heated to a temperature at which it is in a molten state. The molten first fluororesin passes through the sprue 23 and the gate 24, and flows into the cavity 50. The first fluororesin that has flowed into the cavity 50 surrounds the reinforcing material 6 while filling the cavity 50.

[0028] The reinforcing material 6 and the movable-side mold plate 43 are connected by the placing piece 31, and the shaft portion 311 of the placing piece 31 is exposed in the cavity 50. Therefore, the first fluororesin covers the reinforcing material 6 except for the portion of the shaft portion 311 of the placing piece 31. Compared to the temperature of the first fluororesin in a molten state, the temperatures of the movable-side mold plate 43 and the fixed-side mold plate 22 are lower. Therefore, the molten first fluororesin that has flowed into the cavity 50 is cooled and solidified due to the temperature difference with the mold. In this way, a primary molded product having a first fluororesin portion made of the first fluororesin is obtained.

[0029] The solidified primary molded product is ejected from the movable mold plate 43 by the ejection pin 45, and the primary molded product is removed from the injection mold 100. Thereafter, gate cutting, annealing treatment, cutting processing, etc. may be performed on the primary molded product as necessary. In this manner, the primary molded product 11 shown in FIG. 4 is obtained.

[0030] Here, the first fluororesin will be described. The first fluororesin is a melt-type fluororesin. Most of the fluororesin molded product according to the embodiment is composed of a first fluororesin part made of the first fluororesin. Therefore, compared with the case where most of the fluororesin molded product is composed of a non-melt-type fluororesin, the amount of particles (impurities) on the molded product surface can be reduced. That is, a fluororesin molded product with excellent low particle properties can be obtained.

[0031] The first fluororesin is, for example, at least one selected from the group consisting of perfluoroalkoxyalkane (PFA), tetrafluoroethylene-perfluoromethoxy copolymer (MFA), ethylene-tetrafluoroethylene copolymer (ETFE), perfluoroethylenepropene copolymer (FEP) and polyvinylidene fluoride (PVDF). The first fluororesin may consist of only one of these fluororesins, or may be a mixture of two or more of them. From the viewpoint of improving the high-temperature durability and chemical resistance of the fluororesin molded product, it is preferable that the first fluororesin contains PFA. The first fluororesin may consist of only PFA.

[0032] The melt flow rate of the first fluororesin is, for example, in the range of 2 g / 10 min to 50 g / 10 min. In injection molding, increasing the melt flow rate of the resin to be injected makes it easier for the resin to reach every corner of the cavity. In order to increase the melt flow rate without changing the type of resin, it is effective to reduce the weight average molecular weight of the resin.

[0033] 1 and 2 show a mold for injection molding, but the manufacturing method of a fluororesin molded article according to the embodiment may be performed by transfer molding instead of injection molding. For example, a transfer pot may be used as the fixed mold, and the first fluororesin may be melted in the transfer pot, and then the first fluororesin may be caused to flow into the cavity through a sprue by the piston movement of a plunger.

[0034] Fig. 4 is a partially cutaway cross-sectional view that shows the obtained primary molded product 11. Fig. 4(a) shows a state in which the holders 31a and 31b are attached to the primary molded product 11. Fig. 4(b) is an enlarged partially cutaway cross-sectional view that shows a state in which the holder 31a has been removed from the primary molded product 11. The primary molded product 11 has a rib 2.

[0035] The above-mentioned injection molding produces a primary molded product 11 with the mounting piece attached, as shown in FIG. 4(a). When the mounting piece 31a is removed, a primary molded product 11 having a space 32a is produced, as shown in FIG. 4(b). The space 32a is made up of a through hole 11a provided in the primary molded product 11 and a hole 6a provided in the reinforcing material 6. The through hole 11a has a shape corresponding to the shape of the shaft portion 311a of the mounting piece 31a. The hole 6a has a shape corresponding to the shape of the male screw portion 312a of the mounting piece 31a. In other words, the space 32a is a space corresponding to a shape that combines the shape of the shaft portion 311a and the shape of the male screw portion 312a of the mounting piece 31a.

[0036] Similarly, the primary molded product 11 further has a space 32b (not shown) that corresponds to the shape of the shaft portion 311b of the placement piece 31b and the shape of the male screw portion 312b.

[0037] Next, a method for sealing the space 32 of the primary molded product 11 with the second fluororesin will be described with reference to Figs. 5 to 8. The space 32 of the primary molded product 11 is sealed to obtain a fluororesin molded product. Fig. 5 shows a schematic diagram of a procedure for inserting a plug 33A made of the second fluororesin into the space 32a and performing heat pressing. Fig. 5(a) is a schematic cross-sectional view showing an enlarged view of the space 32a and its periphery. Fig. 5(b) is a cross-sectional view showing a schematic diagram of the plug 33A inserted into the space 32a being heat pressed. The plug 33A inserted into the space 32a is melted, so that at least a part of the space 32a is filled with the second fluororesin.

[0038] For sealing, a plug 33A made of the second fluororesin is prepared in advance. The plug 33A can be prepared separately, for example, by injection molding. The shape of the plug 33A is not particularly limited, but for example, the plug 33A includes a cylindrical shaft portion 331 and a head portion 330 having a diameter larger than that of the shaft portion 331. The shaft portion 331 is formed, for example, with a diameter and length that allow it to be inserted into a hole 6a provided in the reinforcing material 6. The head portion 330 is formed, for example, with a diameter and length that allow it to be inserted into the through hole 11a. It is preferable that the plug 33A has a shape corresponding to the space portion 32a.

[0039] The head 330 of the plug 33A preferably has ribs 330a and 330b. The shaft 331 of the plug 33A preferably has ribs 331a. The head 330 and shaft 331 have ribs, which can prevent a gap from being generated between the plug 33A and the inner wall of the primary molded product 11 that defines the space 32a. The plug 33A preferably has a configuration that allows it to be inserted deeper into the space 32 by torque. For example, the top surface 332 of the head 330 of the plug 33A preferably has a recess 333 into which a hexagonal wrench can be fitted, as shown in FIG. 6.

[0040] As shown in FIG. 5(b), when the plug 33A is inserted into the space 32a, at least three points, the ribs 330a, 330b, and 331a, come into contact with the inner wall defining the space 32a. In this way, the plug 33A and the space 32a are in contact with each other at three or more points, so that the space 32a can be sealed with high precision by the plug 33A. Then, the plug 33A is subjected to heat pressing. Specifically, a heat pressing plate 120 is pressed against the upper surface 332 of the plug 33A and the upper surface 110 of the primary molded product 11 along a pressing direction P.

[0041] The conditions of the heat press can be adjusted appropriately depending on the type of the second fluororesin constituting the plug 33A. For example, when the plug 33A is made of PFA, the heat press plate 120 can be set at a temperature of 320°C to 400°C, and the heat press can be performed for 10 to 60 seconds at a pressure of 0.01 MPa to 0.6 MPa. If the temperature of the heat press is too high, the fluororesin will decompose, so the conditions are adjusted taking into consideration the melting point of the second fluororesin used. By performing the heat press, the plug 33A melts and the space 32a is filled with the molten second fluororesin. It is preferable that the entire space 32a is filled with the second fluororesin.

[0042] The shape of the plug to be inserted into the space 32a is not limited to the shapes shown in Figures 5 and 6. The plug may have a shape shown in Figure 7. Plug 33B shown in Figure 7 has a shape similar to that of plug 33A except for the shape of its shaft portion 331. Shank 331 of plug 33B does not have a rib, but has a tapered portion 331b at the joint with head 330.

[0043] When the plug 33B is inserted into the space 32a shown in Fig. 7(a), at least three points, i.e., the ribs 330a, 330b and the tapered portion 331b, come into contact with the inner wall defining the space 32a, as shown in Fig. 7(b). The plug 33B and the space 32a are in contact with each other at three or more points, so that the space 32a can be sealed with high precision by the plug 33B. Then, the heat press is performed in the same manner as in the case of the plug 33A described above.

[0044] Thereafter, the heat press plate 120 is pressed against the upper surface 110 of the primary molded product 11 and allowed to cool, thereby solidifying the second fluororesin. In this manner, a fluororesin molded product can be obtained in which the space 32 that the primary molded product 11 had is sealed with the second fluororesin. The portion of the fluororesin molded product that is made of the second fluororesin is referred to as the second fluororesin part. Also, the portion of the fluororesin molded product that is made of the above-mentioned first fluororesin is referred to as the first fluororesin part.

[0045] FIG. 8 is a cross-sectional view that shows the solidified second fluororesin part 7a and its periphery. It is preferable that there is no gap between the inner wall that defines the space part 32a and the second fluororesin part 7a. It is also preferable that there is no or almost no step at the boundary between the upper surface 332 (exposed part of the second fluororesin part 7a) of the head part 330 of the plug 33 and the upper surface 110 of the primary molded product 11. In other words, it is preferable that the boundary is flat. After sealing the space part with the second fluororesin, at least a part of the fluororesin molded product may be cut. This can improve the dimensional accuracy and increase the flatness of the boundary.

[0046] The second fluororesin may be a melt-type fluororesin usable as the first fluororesin described above, or may be a non-melt-type fluororesin. That is, the second fluororesin is, for example, at least one selected from the group consisting of PFA, MFA, ETFE, FEP, PVDF, and polytetrafluoroethylene (PTFE). The second fluororesin may consist of only one of these fluororesins, or may be a mixture of two or more of them.

[0047] The second fluororesin and the first fluororesin may have different compositions, but preferably have the same composition. By making them have the same composition, the affinity of the boundary between the plug 33 and the primary molded product 11 is increased after the heat press, and a lower particle property can be obtained. According to one example, both the first fluororesin and the second fluororesin are made of only PFA.

[0048] 5 to 8, a method of sealing the space 32 with the second fluororesin has been described in which a plug made of the second fluororesin is molded in advance, inserted into the space 32, and then subjected to hot pressing, but the method of sealing the space 32 is not limited to this. For example, a welding rod made of the second fluororesin may be prepared, melted, and poured into the space 32, and the molten second fluororesin may be cooled and solidified.

[0049] The manufacturing method for a fluororesin molded product described above provides a fluororesin molded product comprising: a first fluororesin part made of a first fluororesin that is a melt-type fluororesin; a reinforcing material having a hole provided in a space defined by the first fluororesin part; and a second fluororesin part made of a second fluororesin and filling the hole.

[0050] Since at least a part of the fluororesin molded product contains a reinforcing material, the fluororesin molded product has superior high-temperature durability compared to a case where the fluororesin molded product does not have a reinforcing material. Therefore, even if the weight-average molecular weight of the first fluororesin is reduced in order to increase the melt flow rate, the deformation of the fluororesin molded product can be suppressed. Furthermore, at least the part (first fluororesin part) made of the first fluororesin of the fluororesin molded product is formed of a melt-type fluororesin that can be injection molded or transfer molded. Therefore, the surface of the molded product is smooth and particles as impurities are unlikely to be generated. In other words, the fluororesin molded product has low particle properties.

[0051] Second embodiment According to the second embodiment, there is provided a fluororesin molded product that can be molded by the manufacturing method for a fluororesin molded product described in the first embodiment. An example of the fluororesin molded product is a square tank 1 shown in Figs. 9 to 12. Another example of the fluororesin molded product is a cup 60 for a single-wafer cleaning apparatus shown in Figs. 13 and 14. However, the type of the fluororesin molded product according to the second embodiment is not particularly limited as long as it is a fluororesin molded product that can be manufactured by the manufacturing method for a fluororesin molded product according to the first embodiment.

[0052] 9 to 12 show a square tank 1. The square tank 1 may have, for example, a container structure. Specifically, the square tank 1 includes a rectangular bottom plate 4, frame-shaped walls 3a to 3d extending in a direction perpendicular to the main surface of the bottom plate 4, and a rib 2 surrounding the ends of the walls 3a to 3d. FIG. 9 is a perspective view showing a square tank 1 as a fluororesin molded product according to one embodiment. FIG. 12 is a plan view showing the top surface of the square tank 1 shown in FIG. 9. The X-axis and Y-axis directions are perpendicular to each other, and the Z-axis direction is perpendicular to the X-axis and Y-axis directions.

[0053] The bottom plate 4 of the rectangular tank 1 extends in the X-axis and Y-axis directions, and the wall portion 3 extends in the Z-axis direction. The ribs 2 are the ends of the wall portion 3 and extend from the open end of the rectangular tank 1 along the X-axis and Y-axis directions.

[0054] In the square tank 1, the bottom plate 4, the wall portion 3, and a portion of the rib 2 are made of a first fluororesin portion. As shown in FIG. 12, a reinforcing material 6 is embedded in each of the four sides of the frame-shaped rib 2. Here, as an example, the reinforcing material 6 is a rectangular plate having a predetermined thickness. A portion of the reinforcing material 6 does not have to be embedded in the fluororesin molded product. In other words, a portion of the reinforcing material 6 may be exposed. However, it is preferable that the entire reinforcing material 6 is embedded in the fluororesin molded product.

[0055] A schematic cross-sectional view of the rib 2 along the X-axis direction is shown in Fig. 10. Fig. 10 is a schematic cross-sectional view of the square tank 1 along the XX line shown in Fig. 9. The elongated plate-like reinforcing material 6 is embedded along the short side direction of the square tank 1. The reinforcing material 6 has two holes 6a and 6b into which a part of the insert piece can be inserted when the square tank 1 is manufactured. The square tank 1 also has through holes 11a and 11b that communicate with these holes and penetrate from these holes to the upper surface 110 of the square tank 1. However, the space 32a consisting of the hole 6a and the through hole 11a is filled with the second fluororesin part 7a. The space 32b consisting of the hole 6b and the through hole 11b is filled with the second fluororesin part 7b.

[0056] The second fluororesin parts 7h and 7g on the other short side of the square tank 1 also have shapes corresponding to parts of the pieces used during manufacture, similar to the above-mentioned second fluororesin parts 7a and 7b. The second fluororesin parts 7c and 7d on one long side of the square tank 1 and the second fluororesin parts 7e and 7f on the other long side also have shapes corresponding to parts of the pieces used during manufacture.

[0057] Fig. 11 is a schematic cross-sectional view taken along line XI-XI of the rectangular tank 1 shown in Fig. 9. The reinforcing material 6 is contained within the rib 2. The reinforcing material 6 is embedded at a predetermined distance from each wall surface constituting the rib 2, i.e., the inner wall of the rectangular tank 1, the upper surface 110, the lower end of the rib 2, and the end surface of the rib 2 in the X-axis direction, etc. In this way, the reinforcing material is located within the space defined by the first fluororesin part formed by injection molding with the first fluororesin.

[0058] The square tank 1 has reinforcing material 6 in the rib 2, which can suppress deformation of the wall at the open end of the tank. In other words, the square tank 1 has excellent high-temperature durability. In addition, the first fluororesin part is made of a melt-type fluororesin, so the square tank 1 has low particle generation.

[0059] It is desirable that the thickness of each part constituting the square tank 1 is 3 mm or more.

[0060] In the rectangular tank shown in Figures 9 to 12, the case where the reinforcing material is provided inside the rib has been described, but the reinforcing material may be embedded inside the bottom plate and / or the wall (side wall). Also, although a single tank has been described as an example here, the present invention is not limited to this and can be applied to double tanks, tanks in which the inside of a single tank is divided into multiple spaces, round tanks, triangular tanks, and polygonal tanks, etc.

[0061] Next, a cup 60 for a single-wafer cleaning apparatus, which is another example of a fluororesin molded product, will be described with reference to Figs. 13 and 14. Fig. 13 is a plan view that shows a schematic upper surface of the cup 60. Fig. 14 is a schematic cross-sectional view taken along line XIV-XIV of the cup 60 shown in Fig. 13. The cup 60 can be manufactured, for example, by the manufacturing method for a fluororesin molded product according to the first embodiment described above.

[0062] The cup 60 includes an annular wall surface 61, an upper wall surface 62 extending from the wall surface 61, and a through hole 64 provided in the upper wall surface 62. The annular wall surface 61 is a cylindrical wall surface extending along the Z-axis direction. The upper wall surface 62 is a wall surface extending from the upper end of the wall surface 61 at least in the X-axis direction and / or the Y-axis direction. The through hole 64 has an outer edge concentric with the wall surface 61, and penetrates the upper wall surface 62 from one surface to the other surface. Although not shown, for example, a semiconductor wafer as an object to be cleaned is placed inside the cup 60. A chemical liquid for cleaning the wafer can be supplied onto the surface of the semiconductor wafer through the through hole 64.

[0063] The annular wall surface 61 contains a reinforcing material 6 along the annular ring. The material and shape of the reinforcing material 6 are not particularly limited as long as they can increase the high-temperature durability of the fluororesin molded product, but as an example here, the reinforcing material 6 is a ring made of stainless steel. As described above, there may be multiple reinforcing materials. As the multiple reinforcing materials, for example, a ring-shaped member divided into multiple pieces can be used.

[0064] As shown in Fig. 14, the reinforcing material 6 of the cup 60 has holes 6a and 6b. Although not shown, holes 6c and 6d of the reinforcing material 6 exist at positions corresponding to the second fluororesin parts 7c and 7d in Fig. 13 showing a top view. That is, the reinforcing material 6 has four holes 6a to 6d. These holes are used to hold the reinforcing material 6 in the cavity using a retaining piece during injection molding. In addition, through holes 60a to 60d exist from each of the four holes 6a to 6d of the reinforcing material 6 to the bottom surface 65 of the cup 60 (however, 60c and 60d are not shown).

[0065] The four holes 6a-6d of the reinforcing material 6 and the four through holes 60a-60d form spaces 32a-32d corresponding to the shapes of the pieces used during injection molding. The spaces 32a-32d are all filled with the second fluororesin portions 7a-7d by carrying out the sealing step in the manufacturing method for a fluororesin molded product according to the first embodiment. Thus, the cup 60 includes the four second fluororesin portions 7a-7d.

[0066] In the cup 60, the portion other than the portion constituted by the reinforcing material 6 and the second fluororesin portions 7a to 7d is constituted by the first fluororesin portion.

[0067] The dimensions of the cup 60 are not particularly limited, but are, for example, as follows: The outer diameter of the cup 60 is, for example, within a range of 250 mm to 800 mm. The inner diameter of the cup 60 is, for example, within a range of 205 mm to 550 mm. The height of the cup 60 is, for example, within a range of 60 mm to 200 mm.

[0068] Since the cup 60 contains the reinforcing material 6 along the annular wall surface 61, even if the wall surface 61 is exposed to a high-temperature environment or a high-temperature chemical liquid adheres to the wall surface 61, the deformation of the wall surface 61 can be suppressed. That is, the high-temperature durability of the cup 60 is excellent. In addition, since the first fluororesin portion is made of a melt-type fluororesin, the particulate nature of the cup 60 is low.

[0069] In the cup 60 according to the present embodiment described above, the reinforcing material is contained within the annular wall surface 61, but the position of the reinforcing material is not limited to within the wall surface 61. For example, the reinforcing material may be located inside the upper wall surface 62.

[0070] The present invention is not limited to the above-mentioned embodiment, and can be modified in various ways in the implementation stage without departing from the gist of the invention. In addition, each embodiment may be implemented in combination as appropriate as possible, and in that case, the combined effect can be obtained. Furthermore, the above-mentioned embodiment includes inventions at various stages, and various inventions can be extracted by appropriate combinations of the disclosed multiple constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, if the problem described in the "Problem to be Solved by the Invention" column can be solved and the effect described in the "Effect of the Invention" column can be obtained, the configuration from which the constituent elements are deleted can be extracted as the invention. The invention as described in the claims of the present application as originally filed is set forth below. [1] Inserting a part of the support piece into a hole provided in the reinforcement material; Heating the movable mold and the fixed mold; removably fixing another part of the piece protruding from the reinforcing material to the movable mold side, thereby holding the reinforcing material within a cavity defined between the movable mold and the fixed mold; closing the movable mold and the fixed mold, and injecting a first fluororesin which is a molten fluororesin into the cavity, and then cooling the first fluororesin to form a primary molded product; opening the movable mold and the fixed mold to remove the primary molded product together with the piece; removing the piece from the hole of the reinforcing material to obtain the primary molded product having a space corresponding to the piece; sealing the space of the primary molding with a second fluororesin; A method for producing a fluororesin molded article by a method comprising the steps of: The fluororesin molded product is A first fluororesin part made of the first fluororesin; the reinforcing material provided in the space defined by the first fluororesin portion and having the hole; a second fluororesin portion filled in the hole and made of the second fluororesin; A method for producing a fluororesin molded product comprising the steps of: [2] The method for producing a fluororesin molded product according to [1], wherein the first fluororesin is at least one selected from the group consisting of perfluoroalkoxyalkane, tetrafluoroethylene-perfluoromethoxy copolymer, ethylene-tetrafluoroethylene copolymer, perfluoroethylenepropene copolymer, and polyvinylidene fluoride. [3] The method for producing a fluororesin molded product according to [1] or [2], wherein the second fluororesin is at least one selected from the group consisting of perfluoroalkoxyalkane, tetrafluoroethylene-perfluoromethoxy copolymer, ethylene-tetrafluoroethylene copolymer, perfluoroethylenepropene copolymer, polyvinylidene fluoride, and polytetrafluoroethylene. [4] The method for producing a fluororesin molded article according to any one of [1] to [3], wherein the first fluororesin and the second fluororesin have the same composition. [5] The method for producing a fluororesin molded product according to any one of [1] to [4], wherein the first fluororesin and the second fluororesin each consist solely of a perfluoroalkoxyalkane. [6] The method for producing a fluororesin molded article according to any one of [1] to [5], wherein the reinforcing material is at least one selected from the group consisting of metals, ceramics, and resins. [7] The sealing is preparing a plug made of the second fluororesin and having a shape corresponding to the piece; Inserting the plug into the space of the primary molding; pressing a heat press plate against the plug to melt the plug and fill at least a portion of the space with the second fluororesin; cooling the second fluororesin to form a second fluororesin portion; The method for producing a fluororesin molded article according to any one of [1] to [6] above, which is carried out by a method comprising the steps of: [8] A fluororesin molded product produced by the method according to any one of [1] to [7]. [Explanation of symbols]

[0071] 1...square tank, 2...rib, 3...wall, 4...bottom plate, 6...reinforcing material, 7...second fluororesin part, 11...primary molded product, 11a, 11b...through hole, 20...fixed side mold, 21...fixed side mounting plate, 22...fixed side mold plate, 23...sprue, 24...gate, 31...placement piece, 32...space, 33...plug, 40...movable side mold, 41...movable side mounting plate, 42a, 42b...space a nozzle block, 43...movable side mold plate, 44...ejector plate, 45...ejector pin, 46a, 46b...through hole, 47...piece mounting portion, 50...cavity, 60...single wafer cleaning apparatus cup, 61...wall surface, 62...upper wall surface, 64...through hole, 65...bottom surface, 100...injection molding mold, 120...heat press plate, 310...head portion, 311...shaft portion, 312...male screw portion.

Claims

1. Inserting a part of the placement piece into a hole provided in the reinforcing material; Heating the movable mold and the fixed mold; removably fixing another part of the piece protruding from the reinforcing material to the movable mold side, thereby holding the reinforcing material within a cavity defined between the movable mold and the fixed mold; closing the movable mold and the fixed mold, and flowing a first fluororesin, which is a molten fluororesin, into the cavity, and then cooling the first fluororesin to form a primary molded product; opening the movable mold and the fixed mold to remove the primary molded product together with the piece; removing the piece from the hole of the reinforcing material to obtain the primary molded product having a space corresponding to the piece; sealing the space of the primary molding with a second fluororesin; A method for producing a fluororesin molded article by a method comprising the steps of: The fluororesin molded product is A first fluororesin part made of the first fluororesin; the reinforcing material provided in a space defined by the first fluororesin portion and having the hole; a second fluororesin portion filled in the hole and made of the second fluororesin; A method for producing a fluororesin molded product comprising the steps of:

2. The method for producing a fluororesin molded product according to claim 1, wherein the first fluororesin is at least one selected from the group consisting of perfluoroalkoxyalkane, tetrafluoroethylene-perfluoromethoxy copolymer, ethylene-tetrafluoroethylene copolymer, perfluoroethylenepropene copolymer, and polyvinylidene fluoride.

3. The method for producing a fluororesin molded product according to claim 1 or 2, wherein the second fluororesin is at least one selected from the group consisting of perfluoroalkoxyalkane, tetrafluoroethylene-perfluoromethoxy copolymer, ethylene-tetrafluoroethylene copolymer, perfluoroethylenepropene copolymer, polyvinylidene fluoride, and polytetrafluoroethylene.

4. The method for producing a fluororesin molded product according to any one of claims 1 to 3, wherein the first fluororesin and the second fluororesin have the same composition.

5. 5. The method for producing a fluororesin molded product according to claim 1, wherein the first fluororesin and the second fluororesin each consist solely of a perfluoroalkoxyalkane.

6. 6. The method for producing a fluororesin molded product according to claim 1, wherein the reinforcing material is at least one selected from the group consisting of metals, ceramics, and resins.

7. The sealing is preparing a plug made of the second fluororesin and having a shape corresponding to the piece; Inserting the plug into the space of the primary molding; pressing a heat press plate against the plug to melt the plug and fill at least a portion of the space with the second fluororesin; cooling the second fluororesin to form a second fluororesin portion; The method for producing a fluororesin molded article according to any one of claims 1 to 6, which is carried out by a method comprising the steps of:

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