JP3450597B2 - Fluororesin molding - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel fluororesin molding having an antistatic property. Specifically, an antistatic layer made of a fluororesin whose surface resistivity is adjusted to 10 ¹³ Ω or less by allowing an ion exchange group to exist on the surface layer of a base material made of a fluororesin that does not substantially contain an ion exchange group. By having this, the fluororesin molded article has a good antistatic effect while maintaining the characteristics peculiar to the fluororesin, and has extremely low stain resistance.

[0002]

2. Description of the Related Art Fluorine resins are excellent in chemical resistance, heat resistance, electrical insulation properties and stain resistance and are used in a wide range of industrial fields. However, since the surface resistance of the fluororesin is extremely high, it has a great disadvantage that it is easily charged with static electricity.

For example, a fluororesin wafer carrier used in a semiconductor manufacturing process easily adsorbs fine particles in an atmosphere due to the charging property of the fluororesin, and as a result, the fine particles adsorbed on the wafer carrier are retained by the fine particles. However, there is a problem in that the produced wafer is contaminated and the defective rate of the product obtained by using the wafer is increased.

Further, in a pipe for transferring a flammable liquid, static electricity is generated due to friction caused by the passage of the flammable liquid in the pipe, which may cause ignition.

Conventionally, for the purpose of imparting antistatic properties to a fluororesin molding, a resin composition in which a conductive powder is mixed with a fluororesin and a molding made of the composition are known. For example, JP-A-61-37842, JP-A-62-223255, and JP-A-2-25575.
Japanese Unexamined Patent Publication (Kokai) No. 1 discloses a method for obtaining a molded product from a resin composition in which a fluorocarbon resin such as tetrafluoroethylene is mixed with carbon powder and carbon fiber powder, and fibrous conductive titanium oxide and conductive powder such as zinc oxide. ing.

Further, Japanese Patent Laid-Open No. 8-59864 discloses that
There is disclosed a fluororesin molded product having a surface made conductive by plasma-treating the surface layer of the fluororesin molded product to form C = C bonds, which are C-F bonds broken.

For the purpose of imparting hydrophilicity to a fluororesin molding, Japanese Patent Laid-Open No. 1-98641 discloses a porous tube of fluororesin containing a hydrophilic monomer containing an ion exchange group by irradiation with radiation. A method of graft-polymerizing on the surface of is disclosed.

[0008]

However, among the above, the molded product obtained from the resin composition mixed with the conductive powder needs to be mixed with a large amount of the conductive powder in order to impart the antistatic ability. Therefore, there is a problem that the conductive powder or impurities contained therein is eluted from the obtained fluororesin molding. Such a problem causes a phenomenon of contaminating a substance that comes into contact with the molded body, and particularly when the fluororesin molded body is used as a wafer carrier, the wafer carrier is liable to be caused by particles and the like caused by the eluted conductive powder. This causes a phenomenon that the wafer held on the wafer is contaminated. Further, in the use of a fluid transfer pipe, there is a risk of causing a phenomenon of contamination of the fluid.

Further, since the entire molded body is made of a fluororesin containing the electroconductive powder, the electrical insulation characteristics and stain resistance, which are the characteristics of the fluororesin, are impaired, and applications requiring such characteristics. Use is restricted in.

On the other hand, in the case of a method of introducing a hydrophilic monomer by a graft reaction for the purpose of imparting hydrophilicity, the fluororesin originally belongs to a decomposition type resin in such a reaction, and the monomer and the like are quantitatively and It is difficult to introduce a large amount, and ion-exchange groups are applied only in a very thin thickness of about several hundred angstroms from the surface. In addition, there is a concern that the decomposed resin may cause particles when the surface of the fluororesin molded product is irradiated with radiation.

As a result, the surface resistance of the above fluororesin molded article was not sufficiently reduced, and there was still room for improvement in antistatic effect, stain resistance and the like.

[0012]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a fluororesin molding which has a good antistatic effect and in which the elution of contaminants such as particles from the inside is extremely small. .

According to the present invention, the above object is to provide a fluororesin in which ion-exchange groups are present on the surface of a fluororesin substantially free of ion-exchange groups so as to exhibit a specific surface resistance. Can be achieved by forming an antistatic layer of

That is, according to the present invention, the amount of ion exchange groups is
Less than 0.20 mol% in terms of monomers containing on-exchange groups
The surface resistivity of the base material made of the fluororesin of 10 ¹³ is 10 ¹³ when the ion exchange group made of a perfluorosulfonic acid group or a perfluorocarboxylic acid group is present.
A fluororesin molded article having an antistatic layer made of a fluororesin adjusted to Ω or less.

In the present invention, the base material made of a fluororesin as the base material is substantially free of ion exchange groups. That is, when a resin having an ion exchange group is used as a substrate, a dimensional change occurs due to swelling of the molded body when immersed in a solvent, a chemical solution, or the like, and ions, inorganic substances, or organic substances are adsorbed and permeated. When used for carrier applications, the problem of contamination of the wafer that comes into contact therewith may occur. For example, fluorine-based ion exchange membranes and ion exchange resins are known as fluororesins having an ion exchange group as a base material, but these resins are for the purpose of permeation and adsorption of ions, and are usually It contains about a dozen or more mol% of exchange groups. Therefore, in the field where the stain resistance, which is a characteristic of the fluororesin, is required, such as the above-mentioned wafer carrier, the adsorption property of organic substances, ions, etc. possessed by the fluorine-based ion exchange membrane or the ion exchange resin is not preferable. Further, also in the use of a film made of a fluororesin, which is required to have antistatic ability, or a molded article of a tube, it is not preferable to permeate and adsorb inorganic substances such as ions and water, and organic substances such as alcohol.

Therefore, if the fluororesin does not contain ion-exchange groups or contains ion-exchange groups in an amount not more than the above-mentioned problems, that is, if the fluororesin is substantially free of ion-exchange groups, It can be used as the base material of the present invention without limitation. The amount of ion exchange groups in the fluororesin serving as the base material cannot be unconditionally limited because the dimensional stability, adsorption, and permeability required depending on the application are different, but generally, the amount of ion exchange groups is included. It is preferably less than 0.20 mol%, particularly preferably 0.1 mol% or less in terms of monomer.

In the present specification, the amount of ion-exchange groups contained in the fluororesin is represented by the composition with respect to the monomer units of all monomers of the ion-exchange groups.

Further, the fluororesin constituting the base material of the present invention substantially contains a filler such as the above-mentioned electroconductive substance from which an additive component is eluted, from the viewpoint of contamination when the molded body is used. Those that do not are preferably used. When a filler that does not elute is added, it is desirable to use an amount that does not significantly deteriorate the properties of the fluororesin substrate.

In the present invention, specific examples of the fluororesin preferably used as the base material include polytetrafluoroethylene, tetrafluoroethylene and an alkyl vinyl ether, and / or a functional group convertible to an ion exchange group described later. With a monomer (hereinafter, referred to as a precursor monomer) having, a copolymer of tetrafluoroethylene and hexafluoropropylene and / or a precursor monomer, polymonochlorotrifluoroethylene, tetrafluoroethylene and perfluorodimethyl Examples thereof include copolymers with dioxoles and polyperfluoroalkenyl vinyl ethers.

The above-mentioned alkyl vinyl ether is a perfluoroalkyl vinyl ether or a polyfluoroalkyl vinyl ether partially having a hydrogen atom. Specifically, the general _{formula, R f (CH 2) l} OCF = CF 2 ( where R _f is a perfluoroalkyl group, l is 0 or 1.) Said alkyl vinyl ether, copolymer obtained The ratio of hydrogen atoms to 0.2% by weight or less, preferably,
It is preferably used in the range of 0.15% by weight or less.

Of the above-mentioned fluororesins, perfluorocarbon resins such as polytetrafluoroethylene, copolymers of tetrafluoroethylene and perfluoroalkyl vinyl ether, and copolymers of tetrafluoroethylene and hexafluoropropylene are heat-resistant. Resistance, chemical resistance,
It is preferably used in terms of stain resistance and the like.

In the present invention, the antistatic layer formed on the surface of the above-mentioned substrate has a surface resistivity adjusted to less than 10 ¹³ Ω, preferably 10 ¹⁰ Ω or less by the presence of an ion exchange group. Made of resin.

In the present invention, the surface resistivity is JI
It carried out according to the method described in SK-6911.

Such an antistatic layer is present on the surface of a base material made of a fluororesin which does not substantially contain an ion exchange group, and the surface resistivity is lowered, whereby a conventional conductive substance is added to improve the antistatic property. Particles are generated from the surface of the applying means in an extremely small amount, and it is useful in applications where contamination of articles such as wafer carriers that come into contact with the particles is a problem. In addition, since the fluororesin serving as the base material does not contain a large amount of additives, the fluororesin molded product has sufficient strength, and is optimal for applications such as the above-mentioned wafer carrier that is subject to a physical load. Further, as compared with the ion exchange resin having the entire ion exchange group, since the impurity ions do not penetrate to the inside, the amount of the adsorbed impurity ions is small, and the contamination of the impurity ions with respect to the article that comes into contact with the obtained fluororesin molded product is low. Very few.

With respect to the fluororesin molding of the present invention, the chemical adsorption amount measured by the method described below is 50 ppb / cm ³ or less,
Particularly, it is 10 ppb / cm ³ or less.

From this, it is understood that the fluororesin molded product of the present invention is most suitable for the application in which the contamination property is a problem, such as the wafer carrier.

When the surface resistivity of the antistatic layer in which the ion exchange group is present in the fluororesin is larger than 10 ¹³ Ω,
The antistatic effect of the obtained fluororesin molded article is insufficient, for example, when the fluororesin molded article is a wafer carrier, static electricity accumulates on the surface and collects particles that are slightly present in the clean room. There is a problem that the wafer held on the wafer is contaminated by the particles.

The ion exchange group present in the antistatic layer is a perfluorosulfonic acid group or a perfluorocarbon group.
Rubonic acid group. These ion-exchange groups are perfluorinated.
Chemically via carbon chain or perfluoroether chain
It is bonded to a fluororesin.

[0029]

To describe these ion-exchange groups in more detail, the perfluorosulfonic acid group is represented by the following general formula: --CFR _F SO ₃ M (where R _F is F or CF ₃ , M is a hydrogen atom, an alkali metal, Or a group represented by NR ' ₄ (wherein R'is a hydrogen atom or a lower alkyl group),
The perfluorocarboxylic acid group is represented by the following general formula —CFR _F CO ₂ M (where R _F and M are the same as above).
It

Among these ion-exchange groups, the anion-exchange group is generally lower in chemical resistance than the cation-exchange group, and thus the cation-exchange group is preferable. In addition, the perfluorosulfonic acid group has good heat resistance to the perfluorocarboxylic acid group, and when the counter ion to be bonded is a hydrogen ion, it has a higher antistatic ability than the perfluorocarboxylic acid group, which is preferable.

In the present invention, the antistatic effect of the ion exchange group can be confirmed by the voltage decay rate. Generally, a voltage of 10 kV is applied for 1 minute, and the voltage decay rate after 1 second is 70% or more, It is preferably 90% or more.

The means for adjusting the surface resistivity of the antistatic layer to the above range is not particularly limited as long as it is a fluororesin containing an ion exchange group. Generally, in the antistatic layer, the concentration of ion exchange groups in the fluororesin is 0.25 mol% or more, preferably 0.2.
It is effective to have a layer of 5 to 20 mol%, more preferably 0.25 to 18 mol%. That is, in the case of a layer in which the amount of ion exchange groups is less than 0.25 mol%, the antistatic ability is not sufficiently exhibited even if the thickness is increased, and it is difficult to stably impart the antistatic property. Further, if it exceeds 20 mol%, the antistatic ability is high, but excessive adsorption of water, impurity ions and the like or swelling due to contact with water, alcohol and the like causes deformation of the fluororesin molded article and an antistatic layer. May cause partial peeling, which is not preferable.

In the antistatic layer of the present invention, since the side chain of the fluororesin contains an ion-exchange group chemically bonded, the antistatic effect is remarkably maintained for a long period of time, and contact with a liquid is prevented. Even if it is performed for a long period of time, its effect is not lost or reduced.

Furthermore, in the antistatic layer, the ion-exchange group may be present in the depth direction of the antistatic layer uniformly, or continuously or stepwise from the surface in the depth direction of the antistatic layer. You may make it exist so that the concentration may be lowered. In the latter case, the antistatic layer is provided with a concentration gradient so as to include a layer formed of a fluororesin having an ion exchange group content of 0.25 mol% or more.

In the above embodiment, the thickness of the layer containing the ion exchange groups of the antistatic layer at a concentration of 0.25 mol% or more is 1 μm or more, preferably 10 μm or more to achieve the surface resistivity. Preferred for. That is, when the thickness of the layer is less than 1 μm, the antistatic ability of the antistatic layer is not sufficient and it is difficult to stably impart the antistatic property to the fluororesin molding. Further, there is no particular upper limit to the thickness of the antistatic layer, and even if it is too thick, there is no particular problem in terms of antistatic property.

However, if the ion exchange group of the antistatic layer is 0.
If the thickness of the layer contained at a concentration of 25 mol% or more is too large, the strength of the fluororesin molding will be reduced, and the presence of ion exchange groups will cause adsorption of water and impurity ions. Have a problem.

Therefore, when the fluororesin molding of the present invention is used for a wafer carrier or the like described below, the upper limit of the thickness of the layer containing the ion exchange group of the antistatic layer at a concentration of 0.25 mol% or more. Is 50 with respect to the thickness of the base material.
% Or less, preferably 40% or less, more preferably 30%
The following is preferable. In particular, the upper limit of the thickness of the layer is more preferably 500 μm or less in absolute thickness.

When the fluororesin molded product is used for thin films such as films and sheets which will be described later, tubes, pipes and the like, the properties of the fluororesin such as insulation properties, ion impermeability, chemical resistance, etc. In order to sufficiently exert the effect, it is preferable to control the upper limit of the thickness of the layer so that the thickness of the substrate is 10 μm or more.

In the present invention, the antistatic layer is generally present on the entire surface of the molded product, but it may be present on a part of the surface of the molded product depending on the application.

For example, the structure may be such that one surface of a thin material such as a film or sheet has an antistatic layer on the inner or outer surface of a tube or pipe, and the other surface does not have an antistatic layer. . For example, the fluororesin molded article can be sufficiently used in applications where static electricity is a problem on one side and static electricity is not a problem on the other side.

The thickness of the antistatic layer, the amount of ion-exchange groups present and the thickness of the substrate of the present invention are the infrared absorption spectrum (hereinafter referred to as I
It is abbreviated as R spectrum. ) Can be found by measuring. That is, a film is cut out vertically from the surface of the fluororesin molded article of the present invention with a thickness of several tens to several hundreds of μm, and an IR spectrum is transmitted from the surface at intervals of several μm,
Or by measuring the reflection spectrum, or by shaving from the surface of the fluororesin molding of the present invention at several to several tens of μm, and measuring the reflection spectrum of the cut surface,
If there is an ion exchange group characteristic absorption derived from the base, for example, 1060cm around ^-1, 1680 cm around ^-1,
And 1780cm respectively around ^-1 perfluorosulfonic acid salt (-SO ₃ Na), perfluoro carboxylate (-CO ₂ Na), and perfluoro carboxylic acid groups (-CO ₂ H) is observed, these absorption The portion where is present can be determined as the thickness of the antistatic layer, and the amount of ion exchange groups present can be determined from the absorption strength.

On the other hand, when no ion-exchange group is present, these characteristic absorptions are not observed and polytetrafluoroethylene, a copolymer of tetrafluoroethylene and an alkyl vinyl ether, and a copolymerization of tetrafluoroethylene and hexafluoropropylene. Combined, absorption derived from polymonochlorotrifluoroethylene is 1200-1300 cm
^-1 , in the vicinity of 1420 cm ⁻¹ , 1710 cm ⁻¹ , and 1780 as absorption derived from a group convertible to an ion exchange group.
cm ^-1 vicinity, and 2100 cm ^-1 respectively perfluorosulfonic acid fluoride group near (-SO ₂ F), perfluoro carboxylic acid chloride group (-CO ₂ Cl), perfluoro carboxylic acid ester group (-CO ₂ CH ₃ ), And a perfluorocyano group (—CN) are observed, and the portion having the absorption can be the thickness of each layer.

The specific shape of the fluororesin molding according to the present invention is not particularly limited. For example, in FIG.
Examples thereof include a structure such as a wafer carrier having the structure shown in (1), a tubular body such as a tube and a pipe, and a thin molded body such as a sheet and a film.

The method for producing the fluororesin molding of the present invention is not particularly limited, but the following method can be mentioned as an example of a suitable production method.

1. A molded product is molded from a fluororesin having a group that can be converted into an ion-exchange group (hereinafter simply referred to as a precursor), and then the ion-exchange existing in the precursor existing within a predetermined thickness range from the surface of the molded product. A method for producing a fluororesin molded article in which a base material is composed of a precursor and an antistatic layer is formed on the surface thereof by forming an antistatic layer by converting a group that can be converted into a group into an ion exchange group (manufacturing Method 1), 2. A molded body is molded from a mixture of a precursor and a fluororesin that does not substantially have an ion-exchange group and a group that can be converted into an ion-exchange group, and then the precursor is present within a predetermined thickness range from the surface of the molded body. By converting a group that can be converted into an ion-exchange group present in the base material into a precursor and a group of a fluororesin that does not substantially have a precursor-convertible group and an ion-exchange group 2. A method for producing a fluororesin molded article having the antistatic layer formed on the surface thereof (Production Method 2), After obtaining a molded article using a fluororesin that does not substantially have a group that can be converted to an ion exchange group and an ion exchange group,
On its surface, the precursor is fused to a predetermined thickness, and then the group capable of being converted into an ion exchange group by converting the group capable of being converted into an ion exchange group in the precursor into an ion exchange group and an ion. 3. A method for producing a fluororesin molded article in which an antistatic layer is formed on the surface of a base material made of a fluororesin having substantially no exchange group (Production Method 3), 4. A fluororesin that does not have a group that can be converted to an ion-exchange group or a ion-exchange group and a precursor are co-extruded to form a multi-layer, and then the ion-exchange group in the precursor is converted to an ion-exchange group and charged. By forming the prevention layer,
Method for producing a multi-layer fluororesin molded article in which an antistatic layer having a predetermined thickness is formed on the surface of a base material made of a fluororesin having substantially no group capable of being converted into an ion exchange group and an ion exchange group (production method 4) etc. are mentioned.

Therefore, in the production of the fluororesin molding of the present invention, a production method suitable for the purpose of use, the type of resin used, etc. may be selected. In this case, in order to form the antistatic layer with high accuracy in thickness, the manufacturing methods 3 and 4 are preferable among the above manufacturing methods.

The above manufacturing method will be described in detail below.

The method for forming the fluororesin having an ion exchange group which constitutes the antistatic layer is, for example, a method in which a monomer having a group capable of being converted into an ion exchange group and a fluoroolefin are copolymerized and then converted into the ion exchange group. The method of converting into an ion exchange group is mentioned. The fluororesin having an ion exchange group obtained by this method has the following general formula

[0050]

[Chemical 1]

(However, R is composed of a perfluorocarbon chain or a perfluoroether chain, specifically,-(CF ₂ ) _m- (where m is an integer of 2 to 10), or

[0052]

[Chemical 2]

(Where n is an integer of 1 to 3), R _F is as described above, Z is SO ₃ M, or C.
O ₂ M (where M is as described above),
A is _{-CF 3, -O (CF 2)} d CF 3, -OCH 2 (C
F ₂ ) _e CF ₃ (where d is 0 or a positive number from 1 to 7, e
Is a positive number from 1 to 7. ) Or a chlorine atom. ).

Specifically, the fluororesin having a group capable of being converted into an ion exchange group, which is preferably used in the production method 1, is produced by copolymerization of tetrafluoroethylene and a monomer having a group capable of being converted into an ion exchange group. In this case, for the purpose of improving the moldability and physical properties of the copolymer, 30 mol% or less of hexafluoropropylene relative to tetrafluoroethylene, the following general formula CF ₂ ═CFO (CH ₂ ) _a C _b F _{2b + 1} ( However, a is 0 or 1 and b is an integer of 1 to 10.) Alkyl vinyl ethers represented by or monochlorotrifluoroethylene can be mixed and used.

Further, the monomer having a group capable of being converted into an ion exchange group is a monomer having a group capable of being converted into a perfluorosulfonic acid ion exchange group, represented by the following general formula CF ₂ ═CFO [CF ₂ CF (CF ₃ ) O] _o CF ₂ CFRF
A monomer represented by SO ₂ X (where X is F or Cl, RF is F or CF ₃ , and o is an integer of 1 to 3) is also converted into a perfluorocarboxylic acid ion exchange group. Examples of the monomer having such a group include the following general formula CF ₂ ═CFO [CF ₂ CF (CF ₃ ) O] _p (CF ₂ ) _q Y (where Y is CO ₂ R (where R is a lower alkyl group). ), CN, COF, COCl, p is an integer of 1 to 3, and q is an integer of 2 to 8.) or CF ₂ ═CFO (CF ₂ ) _r OCF (CF ₃ ) Y (provided that Y is CO ₂ R (provided that R is a lower alkyl group), CN, COF or COCl, and r is an integer of 2 to 8) is preferably used.
More specifically, examples of the monomer having a group capable of being converted into the ion exchange group are CF ₂ ═CFOCF ₂ CF ₂ S
O ₂ F, CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂
SO ₂ F, CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ C
F (CF ₃ ) OCF ₂ CF ₂ SO ₂ F, CF ₂ = CFOCF ₂
CF (CF ₃ ) SO ₂ F, CF ₂ = CFOCF ₂ CF (CF
₃ ) OCF ₂ CF (CF ₃ ) SO ₂ F, CF ₂ ═CFO (C
F ₂ ) _3-8 CO ₂ CH ₃ , CF ₂ = CFOCF ₂ CF ₂ OCF ₂
It can be mentioned _{CF (CF 3) CO 2 CH} 3.

Further, these monomers may be used alone or in combination without any problem.

For the copolymerization of tetrafluoroethylene and a monomer having a group capable of being converted into an ion exchange group, known methods can be used without any limitation. That is, the optimum polymerization method among the solution polymerization method, suspension polymerization method, and emulsion polymerization method may be selected in consideration of conditions such as copolymerizability.

In either case, copolymerization is carried out by dissolving tetrafluoroethylene under pressure in a dispersion or solution of a monomer having a group capable of converting into an ion exchange group.
When using another monomer in addition to the monomer or tetrafluoroethylene having a group that can be converted to an ion exchange group,
If the monomer is a gas such as hexafluoropropylene, it may be mixed with tetrafluoroethylene, and if it is a liquid such as an alkyl vinyl ether, it may be mixed with a monomer having a group capable of being converted into an ion exchange group and polymerized.

In the case of emulsion polymerization or suspension polymerization without using an organic solvent, water is suitable as the dispersion medium. On the other hand, solution polymerization, in the case of suspension polymerization using an organic solvent, the organic solvent acts as a chain transfer agent, lowers the molecular weight of the polymer, because the physical properties of the resulting copolymer may be poor,
The solvent used is preferably a fluorine-based liquid. In particular,
Perfluoroalkanes such as perfluorobutane, perfluoropentane, perfluorohexane, perfluoroheptane, perfluorooctane, perfluorocycloalkanes such as perfluorocyclobutane, perfluorocyclohexane, perfluoroethers, perfluorotributylamine Perfluoro tertiary amines such as, perfluoromorpholines, chlorofluoroethanes such as trifluoromonochloroethane, and the like are preferably used.

As the polymerization initiator, a persulfate such as ammonium persulfate is preferably used in the case of emulsion polymerization, and a known organic radical generator is used in the case of solution polymerization or suspension polymerization. Considering the heat resistance of the polymer, fluorine-based diacyl peroxides are preferably used, and specific examples include the following.

(CF ₃ CF ₂ CO ₂ ) ₂ , (HCF ₂ CF ₂ C
O ₂ ) ₂ , (ClCF ₂ CF ₂ CO ₂ ) ₂ , (CF ₃ CF ₂ CF
₂ CO ₂ ) ₂ , (CF ₃ CF ₂ CF ₂ OCF (CF ₃ ) CO ₂ )
_{2 In} addition, the pressure of the fluoroolefin during the polymerization cannot be unconditionally determined depending on the monomer composition and the polymerization temperature.
kg / cm ² -G is preferable. Further, the polymerization temperature varies depending on the decomposition temperature of the polymerization initiator used, and therefore cannot be unconditionally determined, but is usually 0 to 100 ° C. and 0 to 5 when a fluorine-based diacyl peroxide is used as the polymerization initiator.
0 ° C is preferred.

The thus obtained copolymer of tetrafluoroethylene and a monomer having a group capable of being converted into an ion exchange group is used in injection molding, extrusion molding, transfer molding,
It can be molded into molds, tubes, pipes, sheets, films and the like by compression molding and the like. A copolymer of a fluoroolefin and a monomer having a group capable of being converted into an ion-exchange group has different rigidity of a molded article depending on its composition, and a composition suitable for the application may be appropriately selected depending on the rigidity.

Next, in the method 2 for producing a fluororesin molded article of the present invention, the fluororesin having a group capable of being converted into an ion-exchange group and the fluororesin having no ion-exchange group specifically described in the production method 1, that is, A molded body can be obtained by molding after mixing with the fluororesin described for the base resin.

However, when polytetrafluoroethylene is used as the base resin, ordinary injection and extrusion molding cannot be performed, but molding can be performed by a polytetrafluoroethylene molding method based on compression molding.

In the method 3 for producing a fluororesin molding of the present invention, the precursor powder or dispersion liquid is applied to the surface of the substrate by an electrostatic coating method, a dip coating method, a spray coating method or the like, and then heated. Can be fused and molded by.

Further, the precursor powder or dispersion is applied to a metal mold whose inner surface is shaped according to the shape of the base material by the above-mentioned electrostatic coating method or the like to form a precursor layer. After that, a method in which the substrate is put in the frame and heated to fuse the precursor layer and the substrate is also possible.

In this case, since the base resin is heated and fused depending on the application without changing its shape, the melting point of the copolymer of tetrafluoroethylene and a monomer having a group capable of being converted into an ion exchange group is set to the base resin. 10 ℃ from the melting point of
It is preferable to keep the temperature as low as 20 ° C. In order to obtain such a copolymer, in the case of a binary copolymer of tetrafluoroethylene and a monomer having a group capable of converting to an ion exchange group, the content of the monomer having a group capable of converting to an ion exchange group is 4 The amount may be not less than mol%, preferably not less than 6 mol% and not more than 20 mol%. Further, the melting point can be lowered to a desired value by adding components such as alkyl vinyl ether and hexafluoropropylene to this system. In the case of a sheet-shaped molded product, it can also be manufactured by laminating the copolymer resin obtained by the manufacturing method 1 previously molded into a sheet and the base resin, and then heating and fusing.

Furthermore, in the method 4 for producing a fluororesin molded article of the present invention, the powder or dispersion liquid of the fluororesin having a group capable of being converted into an ion-exchange group specifically explained in the production method 1,
A laminate can be obtained by co-extrusion molding with a base resin. In this case, a resin that cannot be normally melt-extruded as the base resin, for example, in the case of using polytetrafluoroethylene, is converted to the ion-exchange group specifically described in the production method 1 on preformed polytetrafluoroethylene. A method of extrusion laminating a fluororesin having a group that can be selected can be selected, and when a usual melt-moldable resin is used as the base resin, in addition to the above extrusion laminating method,
A co-extrusion method in which two kinds of resins are laminated while being melt extruded can also be adopted. If necessary, a laminate having three or more layers can also be produced by this manufacturing method.

The conversion of a group capable of being converted into an ion exchange group in the fluororesin molded article produced by the above-described production method into a cation exchange group is preferably a hydrolysis reaction under an alkaline condition which is usually used. This hydrolysis reaction
The molded body may be immersed in an aqueous solution containing several to several tens% of an alkali such as NaOH, KOH, or tetraalkylammonium hydroxide, and heated at room temperature to 100 ° C for several hours to hundreds of tens of hours. In order to accelerate this hydrolysis, it is effective to add an organic solvent such as methanol, ethanol or dimethylsulfoxide.

In the present invention, the thickness of the antistatic layer is important for exhibiting the effects of the present invention, as described above, and in the case of the production method 1 and the production method 2, a group capable of being converted into an ion exchange group is used. It is evenly distributed in the thickness direction, and the thickness of the antistatic layer is adjusted by the hydrolysis conditions. However, the conditions of this hydrolysis reaction cannot be unconditionally determined depending on the concentration of alkali to be used, temperature, type and amount of organic solvent, amount of groups that can be converted into ion exchange groups, composition of resin and the like. Therefore, the thickness of the antistatic layer can be adjusted within the range of the present invention by previously measuring the hydrolysis conditions and the concentration in the thickness direction of the antistatic layer produced by the hydrolysis. In the case of the above production methods 1 and 2, the surface has a high concentration of ion exchange groups and a concentration gradient in which the concentration of ion exchange groups decreases in the thickness direction, but the concentration of ion exchange groups is 0.25 mol% or more. The thickness of the layer having a concentration of 1 μm or more should be 1 μm or more, and a substrate having a concentration of ion exchange groups of less than 0.20 mol%, particularly 0.10 mol% or less should be present under the antistatic layer. Is. Of course, there is no problem even if a transition layer having an ion exchange group concentration between them is present between the antistatic layer and the substrate.

Further, in the production method 3 of the present invention, after coating and fusing a fluororesin having a group capable of being converted into an ion exchange group so as to have a thickness not less than that preferable for exhibiting the effect of the present invention,
The thickness of the antistatic layer may be adjusted depending on the hydrolysis conditions.

In the case of manufacturing methods 3 and 4, the precursor layer may be subjected to conversion treatment so that the concentration of the ion-exchange groups is uniform over the entire thickness, and the same as in manufacturing methods 1 and 2. In addition, conversion treatment to ion exchange groups may be performed so that a concentration gradient of ion exchange groups is formed.

The hydrolysis is preferably carried out on the entire surface of the fluororesin molding, but depending on the application, one surface or a part of the hydrolysis may be carried out.

The counter ion of the cation exchange group after hydrolysis is Na ion, K ion or hydrogen ion, but there is no problem in conversion to other metal ion, hydrogen ion or ammonium ion by any known method. Adopted.

[0075]

As can be understood from the above description, the usual fluororesin has a surface resistance of 10 ¹⁶ Ω or more, and the voltage decay rate after one hour is several%, whereas the present invention has The surface resistance of the fluororesin molded product is less than 10 ¹³ Ω, and the voltage attenuation rate becomes almost 100% within a few seconds, and the fluororesin molded product is practically hardly charged.

The fluororesin molding having the antistatic layer obtained by the present invention hardly generates static electricity unlike the current fluororesins, and dissipates quickly when static electricity occurs. Further, since the fluororesin molded product of the present invention does not substantially have an ion exchange group in the base material, when immersed in a chemical solution, there is no adsorption or permeation of ions or inorganic or organic substances, so that contamination from the chemical solution Moreover, when this fluororesin molded product is transferred to other chemicals or water, it does not contaminate these chemicals or water more than necessary, and there is no dimensional change of the molded product. The excellent physical properties possessed can be retained.

Therefore, the molded article of the present invention can be suitably used in the semiconductor manufacturing industry, the food industry, the chemical industry, and the general fields of physics and chemistry where the generation of static electricity is disliked.

Specifically, since there is no adhesion of dust or the like due to static electricity, chemical solution transfer tubes, joints, valves, strainers, chemical solution containers, chips of vacuum tweezers, other peripheral parts during semiconductor manufacturing, jigs such as wafer carriers, etc. Can be suitably used as. In particular, the wafer carrier made of the fluororesin molded product of the present invention is excellent in antistatic property, so that not only the adhesion of fine particles in the use atmosphere due to static electricity to the wafer can be sufficiently suppressed, but also
There are no problems such as generation of particles and contamination by impure ions, and as a result, the defect rate of the wafer can be suppressed low.

Further, the tube of the present invention (including a pipe)
When a flammable liquid is transferred using, static electricity is prevented from being generated and accumulated due to the antistatic effect, so that not only the risk of ignition can be prevented, but also the generation of particles, swelling by the transfer liquid, and Is extremely useful without the problem of permeation of the transfer liquid.

Further, in the field of food production, the use of the molded product of the present invention makes it possible to prevent the adhesion of dust, which is a sanitary problem.

[0081]

EXAMPLES Examples will be shown below to describe the present invention in detail, but the present invention is not limited to these examples.

The surface resistivity, the voltage decay rate, and the amount of chemical adsorbed on the fluororesin molding were determined as follows.

(1) Surface resistivity The surface resistivity was measured according to JIS K-6911, and the surface resistivity was calculated by the following formula.

[0084]

[Equation 1]

Here, ρ _s : surface resistivity (Ω) d: outer diameter of inner circle of surface electrode (cm) D: inner diameter of surface annular electrode (cm) R _s : surface resistance (Ω) voltage 500 V measurement Time 30 seconds Average of 3 times (2) Voltage decay rate Using a static-Honest meter S-5109 (manufactured by Shishido Shokai), a voltage of 10 kV was applied for 1 minute, and the voltage after cutting off the voltage was measured. Resin size: 40 x 40 x 0.25 mm Attenuation rate = (initial voltage-voltage after t time) / initial voltage (unit:%) (3) Adsorption amount of chemical solution A test piece that had been rinsed with ultrapure water for 20 minutes It was put in a cleaned 1-liter quartz container, 500 ml of sulfuric acid for electronics industry was added, and the mixture was kept at room temperature for 10 minutes to adsorb the sulfuric acid to the test piece. Next, the test piece was taken out and rinsed with ultrapure water for 20 minutes, then 500 ml of ultrapure water was added and heated at 80 ° C. After 2 hours, ultrapure water was sampled and analyzed by ion chromatography, and the amount of sulfuric acid contained in the ultrapure water was calculated per 1 cm ^{2 of the} surface area of the test piece, which was defined as the adsorption amount of the chemical solution.

Reference Example 1 After putting 320 g of 1,1,2-trichlorotrifluoroethane which had been purified by distillation in advance into a 500 ml reactor made of stainless steel equipped with a stirrer, the inside was degassed, and then it was flushed with nitrogen gas. Atmospheric pressure was used. 0.039 g of methanol in the reactor
And, after adding 33.5 g of CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ SO ₂ F, the rotation speed of the stirring motor was set to 800 rotations, tetrafluoroethylene was introduced, and the pressure was set to 4 kg / cm ^2. -G
I chose

Next, while maintaining the inside of the reactor at 25 ° C., a 1,1,2-trichlorotrifluoroethane solution of bis (heptafluorobutyryl) peroxide (5% by weight) 1.77
g was introduced to initiate polymerization. During the polymerization, the polymerization temperature is 25
It was kept at ℃. After 120 minutes from the start of the reaction, the pressure in the reactor was released, the reactor was connected to a vacuum pump via a cooling trap and the pressure was reduced while stirring, and low boiling point components such as a solvent and unreacted monomers were recovered in the trap. . After distilling, the reactor was disassembled, the copolymer was taken out and vacuum dried at 150 ° C. for 12 hours to obtain 24 g of the copolymer.

From the measurement results of the nuclear magnetic resonance spectrum and infrared absorption spectrum, 95.7 mol% of the monomer unit based on tetrafluoroethylene in the above copolymer, CF ₂ = CF
It was confirmed that the monomer unit based on OCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ SO ₂ F was 4.3 mol% copolymerized. The specific melt viscosity of this copolymer at 372 ° C. was 4.6 × 10.
It was ⁶ poise.

Example 1 The copolymer obtained in Reference Example 1 was melt-molded into a film having a thickness of 0.25 mm, and then NaOH / DMSO / H ₂ O = 15/25/60 wt.
% Solution and hydrolyzed at 100 ° C. for 24 hours to form an antistatic layer. When the amount of ion exchange groups present in this film was examined, it was about 4.3 mol% on the surface, about 0.28 mol% at 10 μm from the surface, and 0.08 mol% at 20 μm from the surface and near the center. ,
It was 0.02 mol%. Therefore, the thickness of the layer in which the concentration of the ion exchange groups in the antistatic layer is 0.25 mol% or more is 10 μm.

Next, the surface resistivity of this film was measured to be 5.4 × 10 ⁸ Ω, and the voltage attenuation factor was measured to be 100% decay in 1 second. The chemical solution adsorption of this film was measured and found to be 1.0 ppb / cm ² . When this film was immersed in ion-exchanged water overnight, no elongation due to swelling was observed.

Further, 0.2 obtained by the above method.
A particle generation test was performed on a 5 mm film. That is, first, the film is 5 cm × 10 c
m sample, and rinsed with ultrapure water for 10 minutes in a class 1000 clean room. Then, isopropyl alcohol for electronics industry was put in the container, shaken for 5 minutes, and then left to stand. After 1 day, the isopropyl alcohol for electronic industry was replaced, and the mixture was shaken for 5 minutes and allowed to stand. The same replacement operation was repeated, and the number of particles of 0.3 to 2 μm contained in isopropyl alcohol after 1 day, 7 days, and 14 days was counted by a particle counter (KL-2, KL-2).
Measured using 2). 750 pieces / m one day later
90 particles / ml were observed after 7 days and 45 particles / ml after 14 days.

Particles contained in the isopropyl alcohol for electronic industry used in this experiment had a particle size of 20-4.
It was 0 / ml.

For comparison with the above film, PF
By mixing 5% by weight of conductive carbon and 5% by weight of carbon fiber powder with A and 90% by weight with a kneader brabender heated to 350 ° C for 20 minutes, and then melting at 350 ° C and cooling under pressure. A 0.25 mm thick sheet was formed.

5 cm × 10 c cut from the above sheet
The same operation as in Example 25 was performed on 5 samples of m. Particles of 1250 particles / ml after 1 day, 1140 particles / ml after 7 days, and 960 particles / ml after 14 days were observed.

Examples 2 to 4 and Comparative Example 1 According to the method for producing a copolymer of Reference Example 1, four types of copolymers were obtained by changing the content of the group capable of being converted into an ion exchange group. In the same manner as in 1, melt-molded into a film having a thickness of 0.25 mm. Then, NaOH / DMSO / H ₂ O = 15/25 / 60wt%
The solution was immersed in the above solution and hydrolyzed at 100 ° C. for 24 hours to form an antistatic layer.

The ion-exchange group concentration on the surface of the antistatic layer of the film after hydrolysis, the thickness of the layer having an ion-exchange group concentration of 0.25 mol% or more, the surface resistivity, and the voltage decay rate after 1 second. Table 1 shows the results of measurement of the amount of adsorbed chemicals, and the elongation due to swelling in pure water.

[0097]

[Table 1]

Examples 5 to 7 Copolymerization was carried out in the same manner as in Reference Example 1 except that the monomers shown in Table 2 were used as the monomer having a group capable of being converted into an ion exchange group in the method for producing the copolymer of Reference Example 1. Got united.

Next, as in the first embodiment, the thickness is 0.25 mm.
Melt-molded into a film of NaOH / DMSO / H ₂ O = 15/25 / 60wt%
It was immersed in the solution of No. 1 and hydrolyzed at 100 ° C. for 24 hours.

The content of ion-exchange groups on the surface of the antistatic layer, the thickness of the layer having an ion-exchange group concentration of 0.25 mol% or more, the surface resistivity, the voltage decay rate after 1 second, the amount of adsorbed chemical solution, Table 2 shows the results of measuring the elongation due to swelling with pure water.

[0101]

[Table 2]

Example 8 The copolymer obtained in Reference Example 1 was melt-molded into a film having a thickness of 0.25 mm, immersed in a solution of NaOH / DMSO / H ₂ O = 15/25/60 wt%, Hydrolysis was performed at 120 ° C. for 120 hours. The thickness of the layer having an ion exchange group concentration of 0.25 mol% or more in the antistatic layer of the obtained film was 40 μm.

The surface resistivity of the above film was measured to be 1.6 × 10 ⁸ Ω, and the voltage attenuation factor was measured to be 100% in 1 second. Further, the chemical solution adsorption of this film was measured and found to be 1.1 ppb / cm ² .
When this film was immersed in ion-exchanged water overnight, the elongation due to swelling was 0.1%.

Comparative Example 2 The copolymer obtained in Reference Example 1 was melt-molded into a film having a thickness of 0.25 mm and immersed in a solution of NaOH / DMSO / H ₂ O = 15/25/60 wt% to obtain 100 Hydrolysis was carried out at 0 ° C for 1 hour. The thickness of the antistatic layer of the obtained film was 0.5 μm.
The surface resistivity of the above film was measured and found to be> 1 × 10 ¹⁴ Ω. Furthermore, when the voltage decay rate after 1 second was measured, it was attenuated by 4% in 5 minutes. Also, when the chemical solution adsorption of this film was measured, it was 0.8 ppb / cm.
^{Was 2} . When this film was immersed overnight in ion-exchanged water, the elongation due to swelling was 0%.

Example 9 The copolymer obtained in Reference Example 1 was melt-molded into a film having a thickness of 0.25 mm and dipped in a solution of KOH / DMSO / H ₂ O = 15/25/60 wt% to obtain 100 Hydrolysis was carried out at 24 ° C. for 24 hours. The thickness of the layer having an ion exchange group concentration of 0.25 mol% or more in the antistatic layer of the obtained film was 10 μm.
The surface resistivity was measured and found to be 4.4 × 10 ⁸ Ω. Furthermore, when the voltage decay rate was measured, it was 100 in 1 second.
% Attenuated.

Example 10 The copolymer obtained in Reference Example 1 was melt-molded into a film having a thickness of 0.25 mm, and then NaOH / DMSO / H ₂ O = 15/25/60 wt.
% Solution and hydrolyzed at 100 ° C. for 24 hours. This was immersed in a 1N hydrochloric acid solution and stirred at 30 ° C. for 24 hours. The thickness of the layer having an ion exchange group concentration of 0.25 mol% or more in the antistatic layer of the obtained film is 10
was μm. The surface resistivity of the above film was measured and found to be 1.1 × 10 ⁹ Ω. Further, when the voltage decay rate after 1 second was measured, it was 100% decayed in 1 second.

Example 11 The film obtained in Example 10 was immersed in aqueous ammonia and stirred for 24 hours. The surface resistivity of the obtained film was measured and found to be 3.1 × 10 ⁹ Ω. Further, when the voltage decay rate after 1 second was measured, it was 100% decayed in 1 second.

Examples 12 to 14 Polytetrafluoroethylene (hereinafter referred to as PTFE), a copolymer of tetrafluoroethylene and an alkyl vinyl ether (hereinafter referred to as PFA), or tetrafluoroethylene and hexafluoropropylene. The copolymer (hereinafter referred to as FEP) and the copolymer obtained in Example 4 were mixed in a powder state to have a thickness of 0.25.
mm film melt-molded, NaOH / DMSO / H ₂ O = 15/25/60
It was immersed in a wt% solution and hydrolyzed at 100 ° C. for 24 hours.

The mixing ratio of the base material and the fluororesin having a group capable of being converted into an ion exchange group, the content of the ion exchange group on the surface of the antistatic layer of the obtained film, and the concentration of the ion exchange group are 0.25 mol%. The above layer thickness, surface resistivity,
The voltage decay rate after 1 second, the amount of chemical adsorbed, and the elongation due to swelling with pure water were measured, and the results are shown in Table 3.

[0110]

[Table 3]

Examples 15 to 17 PTFE, PFA, tetrafluoroethylene and CF ₂ = CFOC
Copolymer with H ₂ CF ₂ CF ₃
The powder of the copolymer obtained in Reference Example 1 is evenly adhered to the surface of the molded film (containing mol%), and then the powder is put into an electric furnace in a heating atmosphere to melt only the powder on the surface of the film. And attached. This was immersed in a solution of NaOH / DMSO / H ₂ O = 15/25/60 wt% and hydrolyzed at 100 ° C. for 24 hours to form an antistatic layer.

The thickness of the layer in which the concentration of ion-exchange groups in the antistatic layer of the obtained film was 0.25 mol% or more, the surface resistivity, the voltage decay rate after 1 second, the amount of adsorbed chemical, and the swelling with pure water. Table 4 shows the results obtained by measuring the elongation due to.

[0113]

[Table 4]

Example 18 The film obtained in Example 6 was immersed in 1N hydrochloric acid,
The ion-exchange group was converted to the acid type by stirring at 30 ° C. for 24 hours.
The surface resistivity of this film was measured to be 2.1 x 1
It was 0 ¹² Ω. The voltage decay rate after 1 second was 76%.

Reference Example 2 CF ₂ = CFOCF ₂ CF (CF ₃ ) OCF ₂ CF ₂ according to the production method of Reference Example 1.
SO ₂ F 4.8 mol% and tetrafluoroethylene 95.
A copolymer with 2 mol% was prepared.

Example 19 A 6-inch wafer carrier (25 sheets capacity: shown schematically in FIG. 1) was molded from the copolymer obtained in Reference Example 2 by an injection molding method. The wafer carrier was immersed in a solution of NaOH / DMSO / H ₂ O = 15/25/60 wt% and
Hydrolysis was carried out at 0 ° C. for 24 hours.

A part of the obtained wafer carrier was cut out so that the concentration of ion exchange groups in the antistatic layer was 0.2.
As a result of measuring the thickness of the layer of 5 mol% or more, it was 15 μm.

After the wafer was set on this wafer carrier, it was left in a class 1000 clean room for 24 hours. During this time, the number of particles of 0.3 μm or more attached to the entire surface of the wafer held at the end of the wafer carrier was five.

Next, the surface resistivity of this wafer carrier was measured and found to be 1.8 × 10 ⁸ Ω. Further, when a part of the wafer carrier was cut out and the voltage attenuation rate was measured, it was 100% in 1 second.

Comparative Example 3 A wafer carrier was molded in the same manner as in Example 19 except that a commercially available PFA was used, and after setting the wafer, it was left in a class 1000 clean room for 24 hours. The number of particles of 0.3 μm or more attached to the held wafer was about 300.

Next, the surface resistivity of this wafer carrier was measured and found to be> 1 × 10 ¹⁴ Ω. Further, when a part of the wafer carrier was cut out and the voltage attenuation rate was measured, it was 0.8% after 5 minutes and 6% after 30 minutes.

Example 20 A wafer carrier of the same type as in Example 19 was molded by an injection molding method using a commercially available PFA. The copolymer obtained in Reference Example 2 was electrostatically applied to the inside of a SUS mold frame fitted to this wafer carrier, and then the wafer carrier was placed in the frame and placed in an electric furnace heated to 350 ° C.
The precursor was fused to the surface of the wafer carrier. This wafer carrier was immersed in a solution of (CH ₃ ) ₄ N ⁺ OH ⁻ / DMSO / H ₂ O = 15/25/60 wt% and hydrolyzed at 100 ° C. for 24 hours. Several points were cut out from the wafer carrier and the concentration of ion exchange groups was measured. As a result, the concentration near the surface, and about 80 μm and 100 μm from the surface has an average of 4.
It is 8 mol%, 3.8 mol% and 0.05 mol%, and it can be said that the thickness of the antistatic layer is about 95 μm.

The surface resistivity was 2.1 × 10 ⁸ Ω, and the voltage decay rate was 100% in 1 second. Next, when a part of the wafer carrier was cut out and a chemical solution adsorption test was conducted, it was 1.8 ppb / cm ² .

Example 21 A wafer carrier was manufactured in the same manner as in Example 20. The wafer carrier was cut out at several places to measure the concentration of ion exchange groups. As a result, the concentrations in the vicinity of the surface and at about 300 μm and 340 μm from the surface were 4.8 mol%, 4.1 mol% and 0.1 mol% on average, and the thickness of the antistatic layer was about 330 μm. Can be said. The surface resistivity of the wafer carrier is 2.1 × 10.
^{It was 8} Ω, and the voltage decay rate was 100% in 1 second. The amount of the adsorbed drug solution was 35 ppb / cm ² .

Example 22 Using commercially available PFA and the copolymer obtained in Reference Example 2, a tube having an outer diameter of 8 mm and an inner diameter of 6 mm was molded by a two-layer extrusion molding method. In this case, the thickness of the commercially available PFA is 2.95.
mm, the thickness of the copolymer obtained in Reference Example 2 (thickness of the antistatic layer) was 50 μm. Replace this tube with NaOH / D
Immerse in the solution of MSO / H ₂ O = 15/25 / 60wt%,
The time hydrolysis was performed. When the tube was cut open and the surface resistivity was measured, it was 4.1 × 10 ⁸ Ω, and the voltage decay rate was 100% in 1 second. The concentration of the ion-exchange groups in this tube was near the surface, and the concentrations at about 50 μm and 70 μm from the surface were 4.7 mol%, 3.8 mol% and 0.1 mol% on average. It can be said that the thickness is about 65 μm.

When this tube was immersed in pure water overnight, no elongation due to swelling in the length direction or the diameter direction was observed.

Further, sulfuric acid for electronic industry was placed in 10 cm of the tube, placed in a 200 ml quartz container containing ultrapure water, kept at room temperature, and 24 hours later, ultrapure water was analyzed by ion chromatography to permeate a chemical solution. When the amount is calculated, it is 5 × 10
^{It was −12} g · cm / cm ² · s.

Comparative Example 4 Using the copolymer obtained in Reference Example 2, a tube having an outer diameter of 8 mm and an inner diameter of 6 mm was molded by an extrusion molding method. This tube was immersed in a solution of NaOH / DMSO / H ₂ O = 15/25/60 wt% and hydrolyzed at 100 ° C. for 7 days. The tube was cut open and the surface resistivity was measured to be 4.0 × 1.
It was 0 ⁸ Ω, and the voltage decay rate was 100% in 1 second.
Also, the content of ion-exchange groups in the center is 3.2 mol%.
Met. Further, when this tube was immersed in pure water overnight, the elongations due to swelling in the length direction and the diameter direction were 4.8% and 5.3%, respectively, and the permeation amount of the chemical solution was 7 × 10.
^{It was −9} g · cm / cm ² · s.

Example 23 A copolymer of CF ₂ = CFOCF ₂ CF ₂ CF ₂ CO ₂ CH ₃ and tetrafluoroethylene was obtained in the same manner as in Comparative Example 1. This copolymer is
The monomer unit derived from CF ₂ = CFOCF ₂ CF ₂ CF ₂ CO ₂ CH ₃ is 4.2.
It contained mol%. This copolymer was melt-molded into a film having a thickness of 0.35 mm. The film was heated in phosphorus pentachloride / phosphorus oxychloride for 24 hours at 120 ° C. Next, this membrane was washed and dried, and then reacted with dimethylamine in dry ether. The film was then washed with sodium borohydride in a dry dicryme at 10
After the reaction was carried out at 0 ° C. for 18 hours for reduction, the reaction with methyl iodide was carried out in a methanol solution at 60 ° C. for 16 hours to convert to an anion exchange group. As a result of IR analysis, the concentrations of ion exchange groups near the surface and at 75 μm and 120 μm from the surface were 3.8 mol%, 0.26 mol% and 0 mol%, and the antistatic layer was 75 μm. Further, the surface resistivity of the obtained film was measured and found to be 4.5 × 10 ⁸ Ω, and the voltage attenuation factor after 1 second was 100%.

Example 24 The copolymer obtained in Reference Example 1 was melt-molded into a film having a thickness of 0.25 mm and immersed in a solution of NaOH / DMSO / H ₂ O = 15/25/60 wt%, and 100 Hydrolysis was carried out at ℃ for 72 hours. IR
As a result of spectrum measurement, the film surface and 5 from the surface
The amount of ion exchange groups present at 0 μm, 60 μm and 70 μm was 3.8 mol%, 3.7 mol%, 0.25 mol%, 0.0
It was 1 mol%, and no ion exchange group was detected near the center. Therefore, the thickness of the antistatic layer of this film is 6
It can be said to be 0 μm. The surface resistivity of this film was measured to be 5.2 × 10 ⁸ Ω, and the voltage attenuation factor was measured to find that it was 100% attenuated in 1 second. Also, the chemical solution adsorption is 0.9
It was ppb / cm ² , and when it was immersed in ion-exchanged water overnight, the elongation due to swelling was 0.1%.

Comparative Example 5 The copolymer obtained in Reference Example 1 was melt-molded into a film having a thickness of 0.25 mm, immersed in a solution of NaOH / DMSO / H2O = 15/25/60 wt%, and at 100 ° C. The hydrolysis was performed for 168 hours. I
As a result of R spectrum measurement, the film surface, 50 from the surface
The amount of ion-exchange groups present in the vicinity of the center was 4.3 mol%, 1.0 mol%, and 0.8 mol%. The surface resistivity was measured to be 3.8 × 10 ⁸ Ω, and the voltage attenuation factor was measured to result in 100% attenuation in 1 second. Further, the chemical solution adsorption was 65 ppb / cm ² , and when it was immersed in ion-exchanged water overnight, it was expanded by about 4.5% due to swelling.

[Brief description of drawings]

FIG. 1 is a perspective view showing a typical structure of a wafer carrier composed of a fluororesin molding of the present invention.

[Explanation of symbols]

1 Wafer carrier body 2 Wafer holding groove

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI B29K 27:12 C08L 27:12 C08L 27:12 B65D 85/38 S (56) Reference JP-A-55-41810 (JP, A) ) JP 62-276049 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08J 7/12 B29D 23/00 C08J 7/04 H01L 21/68 B65D 85/86

Claims (7)

(57) [Claims] 1. The amount of ion-exchange groups comprises ion-exchange groups.
The surface resistivity of the base material made of a fluororesin of less than 0.20 mol% in terms of the amount of the monomer present is increased by the presence of an ion exchange group made of a perfluorosulfonic acid group or a perfluorocarboxylic acid group. A fluororesin molded article having an antistatic layer made of a fluororesin adjusted to 10 ¹³ Ω or less. 2. An antistatic layer comprising perfluorosulfonic acid
The fluororesin molded article according to claim 1, wherein an ion-exchange group composed of a group or a perfluorocarboxylic acid group is chemically bonded to the fluororesin through a perfluorocarbon chain or a perfluoroether chain. 3. The fluororesin molded article according to claim 1, wherein the antistatic layer comprises a layer made of a fluororesin containing an ion exchange group at a concentration of 0.25 mol% or more. 4. The fluororesin molded article according to claim 1, wherein the voltage attenuation rate after 1 second is 70% or more over 10 minutes at a voltage of 10 kV. 5. The fluororesin molding according to claim 1, wherein in the antistatic layer, the layer made of a fluororesin containing an ion exchange group at a concentration of 0.25 mol% or more has a thickness of 1 to 500 μm. Wafer carrier. 6. A tube made of a fluororesin molded article according to claim 1, wherein an antistatic layer is formed on the inner surface and / or the outer surface, and the substrate has a thickness of 10 μm or more. 7. A film made of a fluororesin molded article according to claim 1, wherein an antistatic layer is formed on at least one surface, and the substrate has a thickness of 10 μm or more.