JP2010260216A - Fluororesin molding and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluororesin molding having high strength and excellent chemical resistance, which can prevent generation of components adversely affecting semiconductors or the like and to provide a method for manufacturing the same. <P>SOLUTION: The fluororesin molding 10 includes: a bottomed cylindrical or cylindrical molding body 1 composed of a fluororesin-containing compound containing a fluororesin (A) and reinforcing fiber (B); and a fluororesin layer 2 provided on the inner surface of the molding body 1 and composed of a fluororesin (C) selected from a polytetrafluoroethylene or a tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fluororesin molded body and a method for manufacturing the same, and more particularly to a fluororesin molded body suitable as a container used in a semiconductor manufacturing process, the medical field, and the like, and a method for manufacturing the same.

  Fluororesin has excellent chemical resistance, heat resistance, and purity, so it is used as a material for containers such as storage containers, processing containers, and cleaning containers used in the semiconductor manufacturing process and medical field. For example, in a semiconductor manufacturing process, a cleaning container made of polytetrafluoroethylene (PTFE) is used.

  In recent years, semiconductor products, glass substrates for LCD, etc. have become larger, and with the progress of mass production of products, large semiconductor products, glass substrates for LCD, etc. can also be processed, and at one time There is a demand for a large container capable of processing a large amount of semiconductor products.

As one of means for meeting the above requirements, it is conceivable to increase the size of the fluororesin container. However, the enlarged PTFE container has a problem that it is inferior in strength.
In addition, PTFE has a relatively high coefficient of thermal expansion among fluororesins, so that expansion and contraction due to temperature change is relatively large. For this reason, the PTFE container has a problem that when it is used in a semiconductor manufacturing process involving a temperature change, the welded portion tends to be broken by repeated expansion and contraction.

On the other hand, for the purpose of improving the mechanical properties of a fluororesin, a composite material in which reinforcing fibers are blended with a fluororesin is conventionally known.
As a conventional technique related to such a composite material, for example, Japanese Patent Application Laid-Open No. 54-114559 (Patent Document 1) prepares a mixture containing tetrafluoroethylene-based resin particles, graphite fibers, water and an organic dispersion medium. A technique is disclosed in which a compound (tetrafluoroethylene resin particles and graphite fiber) is separated from the product, dried, and then compression molded. Japanese Patent Application Laid-Open No. 7-503983 (Patent Document 2) discloses a method for producing a sheet-like composite in which a mixture of a flake-like fluororesin and graphite fiber is heated and pressed.

  However, when a container made of such a composite material is used in a semiconductor wet process, the reinforced fibers such as carbon fibers exposed on the surface of the container may be corroded by the penetration of a chemical solution contained in the container, thereby deteriorating the container. . Further, when a lining material is bonded to the inner surface of such a container, there is a risk of generating impurities (adhesive) that adversely affect the semiconductor product.

  In JP-A-5-287700 (Patent Document 3), a raw material for papermaking mainly composed of fluorine fibers such as PTFE fiber is prepared by a wet papermaking method using a three-dimensional papermaking mold, and obtained. The molded raw material thus obtained is heat treated at a temperature equal to or higher than the melting point of the fluorine fiber to form a preform, and further, the preform is inserted into a male and female mold corresponding to the product dimensions and subjected to heat treatment to be porous. A technique for manufacturing a molded body is disclosed.

Patent No. 3900204 JP 2007-152718 A JP-A-5-287700

  The present invention is intended to solve the problems associated with the prior art as described above, and is suitable for use in semiconductor manufacturing processes, medical fields, etc., has high strength, excellent chemical resistance, semiconductors, etc. An object of the present invention is to provide a fluororesin molded product that hardly generates a component that adversely affects the product and a method for producing the same.

The fluororesin molded body of the present invention is
A bottomed tubular or tubular molded body comprising a fluororesin composition containing the fluororesin (A) and the reinforcing fibers (B);
And a fluororesin layer made of a fluororesin (C) selected from polytetrafluoroethylene or a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer provided on the inner surface of the molded body.

In the fluororesin molded product of the present invention, the reinforcing fiber (B) is preferably a carbon fiber.
The method for producing the fluororesin molded body of the present invention is as follows.
A bottomed tubular or tubular molded body comprising a fluororesin composition containing the fluororesin (A) and the reinforcing fibers (B);
Production of a fluororesin molding comprising a fluororesin layer comprising a fluororesin (C) selected from polytetrafluoroethylene or a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer provided on the inner surface of the molding body A method,
Step (I) of preforming the fluororesin composition to form a preform for the molded body.
Filling the preform with the fluororesin (C) (II),
The preformed body and the fluororesin (C) are heated and pressurized, and then cooled to form a molded body composed of the molded body main body and the block of the fluororesin (C) bonded to the inner surface thereof. Step (III), and step (IV) of cutting the block so that the fluororesin layer comprising the fluororesin (C) remains along the inner surface of the molded body.
It is characterized by having.

As a preferable aspect of the said process (I),
Fluororesin fiber (a) and reinforcing fiber (B) made of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (however, the ratio of both is (a) :( B) = 70 to 90:10) 30 (however, the sum of both is 100) is sprayed onto the mold to form the preform (Ia)
Is mentioned.

  According to the present invention, there is provided a fluororesin molded body having high strength, excellent chemical resistance, and hardly generating a component that adversely affects a semiconductor or the like.

FIG. 1 is a schematic cross-sectional view of a bottomed cylindrical fluororesin molded body of the present invention. FIG. 2 is a diagram schematically illustrating a method for producing a bottomed cylindrical fluororesin molded body of the present invention. FIG. 3A schematically shows a tubular fluororesin molded body of the present invention. FIG. 3A is a cross-sectional view taken along the S1-S2 cross section indicated by the arrow in FIG. FIG. 4 is a schematic cross-sectional view of the tubular fluororesin molded body of the present invention.

Hereinafter, the present invention will be described in more detail by taking a bottomed cylindrical molded body as an example.
[Fluoropolymer molded product]
This will be described with reference to FIG. A fluororesin molded body 10 of the present invention includes a bottomed cylindrical molded body 1 made of a fluororesin composition containing a fluororesin (A) and a reinforcing fiber (B), and an inner surface of the molded body. A fluororesin comprising a fluororesin (C) selected from polytetrafluoroethylene (hereinafter also referred to as “PTFE”) or tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (hereinafter also referred to as “PFA”). Layer 2.

<Molded body 1>
The molded body 1 is made of a fluororesin composition containing a fluororesin (A) and reinforcing fibers (B).

What is necessary is just to select the shape of the molded object main body 1 suitably according to the specific use of the fluororesin molded object 10 of this invention.
Examples of the fluororesin (A) include PTFE, PFA, a copolymer of ethylene and tetrafluoroethylene (ETFE), a copolymer of tetrafluoroethylene and hexafluoropropylene (FEP), and polychlorotrifluoroethylene. (PCTFE), a resin in which a part of fluorine atoms of PTFE is substituted with a substituent (for example, modified PTFE) can be mentioned. Among these, PFA, ETFE, and FEP are preferred because they have a low melt viscosity and are easily compatible with reinforcing fibers.

  Examples of the reinforcing fibers (B) include carbon fibers, glass fibers, aramid fibers, boron fibers, aluminum fibers, silicon carbide fibers, and the like, and examples thereof include short fibers, long fibers, and whiskers.

  Among these, carbon fiber is preferable because of its excellent chemical resistance. As the carbon fiber, any of a PAN (polyacrylonitrile) -based carbon fiber and a pitch-based carbon fiber can be used, and a PAN-based carbon fiber is preferable from the viewpoint of producing a molded article having higher strength.

  The fiber length of the reinforcing fiber (B) is preferably 1 to 30 mm, more preferably 5 to 20 mm. The fiber diameter of the reinforcing fiber (B) is preferably 1 to 15 μm. When the fiber length and fiber diameter are in the above ranges, the effect of reinforcing the fluororesin (A) is sufficiently exhibited.

The reinforcing fiber (B) may be obtained by cutting a reinforcing fiber having a fiber length equal to or longer than the desired fiber length into the desired length.
Examples of commercially available carbon fibers include “STS40 F13” manufactured by Toho Tenax (from which the sizing agent is removed, fiber diameter: 7 μm).

  The weight ratio ((A) :( B)) between the fluororesin (A) and the reinforcing fiber (B) is preferably 70 to 90:10 to 30 (however, the total of both is 100). ). The molded body 1 having a weight ratio in the above range has a particularly high strength.

<Fluorine resin layer 2>
The fluororesin layer 2 is made of a fluororesin (C) selected from PTFE or PFA, and is provided on the inner surface of the molded body 1.

What is necessary is just to select the thickness of the fluororesin layer 2 suitably according to the specific use of the fluororesin molded object 10 of this invention.
<Fluoropolymer molded body 10>
The fluororesin molded body 10 of the present invention is formed from PTFE or PFA on the inner surface of a bottomed cylindrical molded body 1 made of a fluororesin composition containing the fluororesin (A) and the reinforcing fiber (B). Since the fluororesin layer 2 is provided, the reinforcing fiber (B) does not come into contact with the contents of the fluororesin molded body.

  Therefore, for example, even when this fluororesin molded body 10 is used as a cleaning container in a semiconductor process, the chemical solution placed in the container does not corrode the reinforcing fibers (B) and does not deteriorate the container 10. Further, since the molded body 1 and the fluororesin layer 2 are in close contact with each other without using an adhesive or the like, impurities (adhesive) that adversely affect the semiconductor product are not generated.

  Moreover, since the fluororesin molded body 10 of the present invention contains the reinforcing fiber (B) in the molded body 1, the mechanical strength is high, the bottomed cylindrical molded body can be thinned, and the large size It is possible to correspond to For example, even if the fluororesin molded body 10 of the present invention is 2 mm thick, it has a strength equivalent to 10 mm thickness of a conventional bottomed cylindrical molded body made of only a fluororesin.

  Therefore, the fluororesin molded product 10 of the present invention can be used as a container such as a storage container, a processing container, a cleaning container, etc. used for processes such as semiconductor manufacturing and processing, medical treatment, etc. It is preferable as a processing container such as a glass substrate for LCD or a container for processing a large amount of semiconductor devices and the like at a time.

[Method for producing fluororesin molding]
The method for producing the fluororesin molded body of the present invention described above is as follows.
Step (I) of preforming the fluororesin composition to form a bottomed tubular preform for the molded body.
Step (II) of filling the preform with the fluororesin (C),
The preformed body and the fluororesin (C) are heated and pressurized, and then cooled to form a molded body composed of the molded body main body and the block of the fluororesin (C) bonded to the inner surface thereof. Step (III), and step (IV) of cutting the block so that the fluororesin layer comprising the fluororesin (C) remains along the inner surface of the molded body.
have.

<Process (I)>
In step (I), as shown in FIG. 2, the fluororesin composition is preformed to form a bottomed cylindrical preform 4 for the molded body 1.

  As a method for producing a preform, for example, a spray-up method in which a fluororesin composition is sprayed on a mold, a wet papermaking method using a three-dimensional mold, or a fluororesin composition is sucked into a mold. Examples include a deposition method and a manual hand layup method.

As a preferred embodiment of the step (I),
Fluororesin fiber made of PFA (hereinafter also referred to as “PFA fiber”) (a) and reinforcing fiber (B) (however, the ratio of both is (a) :( B) = 70 to 90:10) 30 (however, the total of both is 100) is sprayed onto the mold to form the preform (Ia).

  In this step (Ia), since the PFA fiber (a) is used as the fluororesin raw material of the molded body 1, the PFA fiber (a) and the reinforcing fiber (B) are entangled, and a bottomed cylindrical preform The shape of can be stably maintained. If the step (Ia) is employed, even a three-dimensionally shaped preform can be easily formed.

The PFA is perfluoroethylene represented by tetrafluoroethylene and the formula: CF ₂ ═CF—O—R _f (wherein R _f represents a fluoroalkyl group, preferably a C 1-10 fluoroalkyl group). It is a copolymer with alkyl vinyl ether. A perfluoroalkyl vinyl ether may be used individually by 1 type, and may use 2 or more types together.

  The PFA preferably contains 99.5 to 92% by mass of a structural unit derived from tetrafluoroethylene and 0.5 to 8% by mass of a structural unit derived from perfluoroalkyl vinyl ether (provided that the amount of PFA is 100% by mass). To do.)

  The average fiber length of the PFA fiber (a) is preferably 1 to 50 mm, more preferably 5 to 20 mm. The fiber diameter of the PFA fiber (a) is preferably 10 to 40 μm. When the fiber length and the fiber diameter are within the above ranges, the PFA fiber (a) is particularly well entangled with the reinforcing fiber (B) when mixed with the reinforcing fiber (B). It can be held stably.

The PFA fiber (a) may be obtained by cutting a PFA fiber having a fiber length equal to or longer than the desired fiber length into the desired length.
Examples of commercially available PFA fibers include “HASTEX” (fiber diameter of about 20 μm) manufactured by Toyo Polymer.

The ratio between the PFA fiber (a) and the reinforcing fiber (B) is (a) :( B) = 70 to 90:10 to 30 (however, the sum of both is 100). .
In the step (Ia), a conventionally known spray-up method can be applied. That is, the PFA fiber (a) and the reinforcing fiber (B) can be supplied to the jet fluid and sprayed onto a mold to form a deposit, that is, a preform.

  The PFA fiber (a) and the reinforcing fiber (B) may be separately supplied to the jetting fluid. A mixture containing the PFA fiber (a) and the reinforcing fiber (B) is prepared in advance, and the mixture is jetted. The fluid may be supplied. By preparing the mixture in advance, the molded body 1 having a more uniform composition can be produced.

As this mixture, a dispersion liquid containing the PFA fibers (a) and the reinforcing fibers (B) in the above ratio and a dispersion medium may be prepared.
Examples of the jet fluid include water and air. Examples of the dispersion medium include water, and a dispersant for improving dispersibility, such as a surfactant or polyvinyl alcohol, may be mixed in the dispersion.

In addition, when using a dispersing agent as mentioned above, it is preferable to remove a dispersing agent by water washing etc. from the deposit obtained.
The shape of the mold may be appropriately selected so as to correspond to the shape of the molded body to be manufactured.

  The mold may be a mold that allows the injection fluid and / or dispersion liquid to efficiently pass therethrough, but a net-shaped mold is preferable. When a mesh mold is used, the PFA fibers (a) and the reinforcing fibers (B) can be deposited while allowing most of the jet fluid or dispersion medium to pass through the meshes during the spraying. A preform can be formed.

  The mesh size and the wire diameter of the net-shaped mold may be appropriately set in consideration of the fiber length of the PFA fiber (a) and the reinforcing fiber (B), the passage of the jet fluid or the dispersion medium, etc. The mesh opening may be 0.5 to 10 mm, and the wire diameter may be 0.25 to 1 mm.

  In the step (I), the powder of the fluororesin (A) and the reinforcing fiber (B) (however, the ratio of both is preferably (A) :( B) = 70 to 90:10 in weight ratio). -30 (however, the total of both is 100)) and, if necessary, a thickener or a dispersion medium is mixed to prepare a mixture, and a mold having a shape corresponding to the molded body is prepared. The preform may be formed by applying the mixture to the inner surface. By mixing the powder of fluororesin (A) and reinforcing fibers (B) with a thickener or dispersion medium, the fluororesin and reinforcing fibers can be applied to the inner surface of the mold corresponding to the molded body. The preform which becomes can be formed easily.

Examples of the thickener include water glue and polyvinyl alcohol (PVA), and water glue is particularly preferable.
Examples of the dispersion medium include water and alcohol water, and water is preferable.

  When water paste or the like is used as a thickener and when a dispersion medium such as water is used, a preform including a thickener, dispersion medium, or the like may be formed first. In such a case, it is preferable to remove the thickener, the dispersion medium and the like from the preform.

Examples of the method for removing the thickener, the dispersion medium, and the like include water washing, washing with an organic solvent, and volatilization removal.
When the bulk density of the preform is low and it is difficult to heat and press mold the preform in step (III), before the step (II), the entire preform or one It is preferable to increase the bulk density of the part.

As the method,
Partially heating and pressurizing the deposited body (temperature: about 290 to 350 ° C., pressure: about 0.05 to 1 MPa) to increase the bulk density of the part;
Pressurizing the deposited body as a whole (room temperature, pressure: about 0.05 to 1 MPa) to increase the bulk density;
And the like.

<Process (II)>
In step (II), as shown in FIG. 2, the bottomed cylindrical preform 4 formed in step (I) is filled with the fluororesin (C) selected from PTFE or PFA.

As a form of the said fluororesin (C), a powder, a fiber, a pellet, etc. are mentioned, for example.
The filling amount of the fluororesin (C) may be appropriately adjusted in consideration of the thickness of the preform, the thickness of the molded body, the shape of the mold used for the heat and pressure molding in the step (III), etc. In general, when the filling amount of the fluororesin (C) is increased, the adhesion between the formed body 1 and the fluororesin layer 2 is increased.

<Step (III)>
In step (III), as shown in FIG. 2, the preform and the fluororesin (C) are heated and pressurized, and then cooled. By doing so, the molded body 1 is molded and the fluororesin (C) block 6 is formed on the inner surface thereof. That is, in the step (III), the molded body 1 and the fluororesin (C) block 6 are integrally molded.

  The conditions such as the temperature at the time of the heat and pressure molding may be set so that the fluororesin (A) and the fluororesin (C) are melted. When the fluororesin (C) is PTFE, for example, the temperature may be 320 to 360 ° C., the pressure may be 5 to 25 Mpa, and the time may be 1 to 120 minutes. When the fluororesin (C) is PFA, for example, the temperature may be 300 to 350 ° C., the pressure may be 5 to 20 Mpa, and the time may be 1 to 120 minutes.

In step (III), the pre-molded body and the fluororesin (C) are heated and pressurized by, for example, placing them in a mold having a shape corresponding to the shape of the molded body main body 1 to be formed.
In step (III), since the fluororesin (C) is melted, pressure is evenly applied to the contact surface between the fluororesin (C) and the preform, so that the molded body and the fluororesin (C) A molded body formed by adhering to the block is obtained.

  In cooling, it is preferable that the pressure is gradually lowered while being pressurized, and the pressure is released after sufficiently cooling (for example, to room temperature). By performing the cooling in this manner, it is possible to more reliably prevent the molded body body and the fluororesin (C) from being separated from each other.

<Step (IV)>
In step (IV), as shown in FIG. 2, the block is cut so that the fluororesin layer made of the fluororesin (C) remains along the inner surface of the molded body.

What is necessary is just to set suitably the thickness of the said fluororesin layer which should remain | survive according to the use etc. of the fluororesin molded object of this invention, for example, 0.5-5 mm may be sufficient.
Although the bottomed tubular fluororesin molded body has been described above, the present invention is not limited to the above shape.

  For example, as shown in FIGS. 3 and 4, the fluororesin molding of the present invention is also applicable to cylindrical fluororesin moldings 11 and 12 that are not integrally provided with a bottom plate. In addition, a cylinder, a square tube, etc. are contained in a cylinder shape.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
[Example 1]
Carbon fiber (“STS40 F13” (manufactured by Toho Tenax)) was thoroughly washed with acetone to remove the sizing agent, then dried at 80 ° C. for 2 hours, and then cut to a length of 12 mm.

Further, PFA fibers (“HASTEX” (manufactured by Toyo Polymer)) were cut into a length of 12 mm.
4 g of PFA fiber and 1 g of carbon fiber prepared as described above were put into 20 L of water and stirred to prepare a uniform dispersion.

  Water is sprayed from a spray gun toward a wire mesh (mesh size: 1.40 mm, wire diameter: 0.717 mm (JIS Z 8801)) having a bowl-like shape (maximum diameter 60 mm × depth 25 mm), and the above dispersion is applied to this water stream. Was added dropwise little by little to spray and deposit PFA fibers and carbon fibers on the outer surface of the wire mesh to form a preform.

Next, the preform is placed in a mold (inner dimensions: 76φ × 30L, bottomed cylindrical (cup)), and PTFE powder (“M-18”, About 350 g of Daikin Industries Co., Ltd. was charged, heated to 340 ° C., then pressurized to 10 MPa and held for 10 minutes. These were allowed to cool to room temperature with heating stopped and then cooled, then the pressure was released, and the resulting cup-shaped molded body and the PTFE block (density 2.1 g / d) adhered to the inner surface thereof cm ³ ) was removed from the mold.

  The block of PTFE was cut so that a PTFE layer having a thickness of 1 mm remained along the inner surface of the molded body, and a fluororesin molded body was obtained.

1: molded body body 2: fluororesin layer 10: bottomed tubular fluororesin molded body 3: mold 4: preformed body 5: fluororesin selected from PTFE and PFA (C)
6: Block of fluororesin (C) 11: Cylindrical fluororesin molded body 12: Cylindrical fluororesin molded body

Claims (4)

A bottomed tubular or tubular molded body comprising a fluororesin composition containing the fluororesin (A) and the reinforcing fibers (B);
A fluororesin molding comprising a fluororesin layer made of a fluororesin (C) selected from polytetrafluoroethylene or a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer, provided on the inner surface of the molding body.   The fluororesin molded body according to claim 1, wherein the reinforcing fiber (B) is a carbon fiber. A bottomed tubular or tubular molded body comprising a fluororesin composition containing the fluororesin (A) and the reinforcing fibers (B);
Production of a fluororesin molding comprising a fluororesin layer comprising a fluororesin (C) selected from polytetrafluoroethylene or a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer provided on the inner surface of the molding body A method,
Step (I) of preforming the fluororesin composition to form a preform for the molded body.
Filling the preform with the fluororesin (C) (II),
The preformed body and the fluororesin (C) are heated and pressurized, and then cooled to form a molded body composed of the molded body main body and the block of the fluororesin (C) bonded to the inner surface thereof. Step (III), and step (IV) of cutting the block so that the fluororesin layer comprising the fluororesin (C) remains along the inner surface of the molded body.
The manufacturing method of the fluororesin molded object characterized by having.   The step (I) is a fluororesin fiber (a) and a reinforcing fiber (B) made of a tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (provided that the ratio of both is (a) :( B) = 70-90: 10-30 (however, the sum of both is 100) is a step (Ia) of spraying the mold onto the mold to form the preform. 3. A method for producing a fluororesin molded article according to 3.