JP2011057868A - Method of manufacturing fluororesin molded body and fluororesin molded body formed by the manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a fluororesin molded body which is inexpensive and excellent in conductivity and electromagnetic wave absorbing property, using a smaller amount of a functional filler than in the past, and to provide a fluororesin molded body manufactured by the manufacturing method. <P>SOLUTION: There is provided a method of manufacturing a fluororesin molded body having a sea-island structure, the method including: melting and kneading, at a temperature T<SB>k</SB>, a mixture (ac-1) of a fluoropolymer (a) for sea part having a viscosity α of 10<SP>3</SP>-10<SP>7</SP>P at the kneading temperature T<SB>k</SB>and a functional filler (c) and a fluoropolymer (b) for island part having a viscosity β which is higher than the viscosity α of the fluoropolymer (a) for sea part at the kneading temperature T<SB>k</SB>, the temperature T<SB>k</SB>being equal to or higher than the temperature at which at least the fluoropolymer (a) for sea part melts and lower than both decomposition temperatures of the fluoropolymers (a) and (b), so that the functional filler (c) is dispersed in the fluoropolymer (a) for sea part at a higher concentration than in the fluoropolymer (b) for island part thereby preparing a molten kneaded product (abc-1); and then molding the molten kneaded product (abc-1). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a fluororesin molded body and a fluororesin molded body obtained by the production method, and more particularly to a method for producing a fluororesin molded body having a sea-island structure.

Conventionally, for example, when imparting properties such as electrical conductivity and thermal conductivity to a polymer material, the polymer material is combined with a material (filler) having excellent properties.
When preparing such a composite material of a polymer material and a filler, a method of mixing solid phases using a kneader such as a biaxial extruder, a kneader, or a biaxial roll, or the polymer material as a good solvent In addition, the liquid phases are mixed in a state where the filler is dissolved or dispersed in the solution, and then the solvent is removed to obtain a composite material, or the combination of the solid phase and the liquid phase is mixed. Is known (Patent Document 1).

  However, the composite material produced by the above method is basically in a state where the filler is uniformly dispersed in the polymer matrix (uniform dispersion system). Such a uniform dispersion system may be advantageous for imparting properties such as improving mechanical strength and imparting flame retardancy, but in order to improve conductivity such as conductivity and thermal conductivity, these properties may be used. It is necessary to use a large amount of a filler having a large amount, and there is a problem that the mechanical strength of the composite material is reduced by using a large amount of the filler. In addition, many of the fillers are expensive, and there is a problem that the price of the composite material obtained by using a large amount of fillers increases. Furthermore, when a large amount of filler is used, impurities derived from the filler often occur, and it has been difficult to use the composite material for devices that are desired to reduce impurities such as semiconductor-related devices and electronic devices. .

In order to solve such problems, a method is disclosed in which conductive fillers are unevenly distributed in a composite material, and a conductive path (path) is efficiently formed in the composite material (Patent Documents 2 and 3). .
However, there is no description about a method for improving conductivity in a composite material made of a fluororesin.

JP-A-10-237300 Japanese Patent Laid-Open No. 10-309904 JP 2000-336212 A

  The present invention is intended to solve the problems associated with the prior art as described above, and has the characteristics of a fluororesin (heat resistance, cold resistance, chemical resistance, mechanical characteristics, etc.), and a fluorine-containing polymer. And a functional filler, and a method for producing a fluororesin molded body that is less expensive than conventional and has a low cost, conductivity such as conductivity and thermal conductivity, and excellent electromagnetic wave absorption, and the production It aims at providing the fluororesin molded object manufactured by the method.

The first production method of the fluororesin molded product of the present invention is a mixture (ac-1) of a marine fluoropolymer a having a viscosity α of 10 ³ to 10 ⁷ P at a kneading temperature T _k and a functional filler c. When,
A fluorine-containing polymer for island part b having a higher viscosity β at the kneading temperature T _k than the viscosity α of the sea-part fluorine-containing polymer a;
Melting and kneading at a temperature T _k that is at least equal to or higher than the melting temperature of the fluoropolymer a for sea and lower than the decomposition temperature of the fluoropolymers a and b,
Compared to the fluorine-containing polymer b for islands, the functional filler c is dispersed at a higher concentration in the fluorine-containing polymer a for seas to prepare a melt-kneaded product (abc-1),
Next, this melt-kneaded product (abc-1) is formed.

In addition, the second production method of the fluororesin molded body of the present invention includes a sea part fluoropolymer a having a viscosity α of 10 ³ to 10 ⁷ P at a kneading temperature T _k ,
A functional filler c;
A fluorine-containing polymer for island part b having a higher viscosity β at the kneading temperature T _k than the viscosity α of the sea-part fluorine-containing polymer a;
Melting and kneading at a temperature T _k that is at least equal to or higher than the melting temperature of the fluoropolymer a for sea and lower than the decomposition temperature of the fluoropolymers a and b,
Compared with the fluorine-containing polymer b for islands, the functional filler c is dispersed at a higher concentration in the fluorine-containing polymer a for seas to prepare a melt-kneaded product (abc-2),
Next, this melt-kneaded product (abc-2) is formed.

In the present invention, the melt-kneading temperature T _k is a viscosity at the kneading temperature T _k of the sea part fluoropolymer a alpha (poise), the viscosity at the kneading temperature T _k of the fluoropolymer b for the island It is preferable that β (pores) be in a temperature range that satisfies the relationship β / α ≧ 10 ² .

In the sea part fluorine-containing polymer a and the island part fluorine-containing polymer b used in the present invention, the viscosity α in any of the polymers a and b is between the viscosity and the melting temperature (melting point). As β (P, poise) increases, the melting temperatures (melting points) T _ma and T _mb tend to increase.

In the present invention, the viscosity α, β (P, poise) of the polymers a and b is β / α ≧ 10 ² , particularly preferably β / α ≧ 10 ^4. In this case, the melting temperatures (melting points) T _ma and T _mb of the fluoropolymer a for sea and the fluoropolymer b for island preferably satisfy T _mb > T _ma (° C.).

In the present invention, the sea part fluorine-containing polymer a and the island part fluorine-containing polymer b have a melting temperature (melting point) T _ma or T _mb of a lower temperature to a decomposition temperature T _da or T _db . Of these, in the lower temperature range, it is preferable to use those in which the relationship between the viscosity α and β (P, Poise) is β> α at any temperature.

In the method for producing a fluororesin molded body of the present invention, the sea part fluoropolymer a is preferably PFA, and the island fluoropolymer b is preferably PTFE.
In the method for producing a fluororesin molded body of the present invention, the functional filler c is preferably carbon black.

Here, “functionality” means conductivity and electromagnetic wave absorption.
The production method of the fluororesin molded product of the present invention is such that the blending amount of the functional filler c in the total (a + c) 100% by volume of the sea part fluoropolymer a and the functional filler c is 0.1 to 50% by volume. It is preferable that

  In the method for producing a fluororesin molded product of the present invention, 25 parts of the above-mentioned island-containing fluoropolymer b is used with respect to 100% by volume (a + b) of the sea-part-containing polymer a and the island-part fluoropolymer b. It is preferably used in an amount of ˜75% by volume.

The fluororesin molded product of the present invention is obtained by any one of the above production methods.
The fluororesin molded body according to the present invention is preferably used for heat conduction, electrical conduction, or electromagnetic wave absorption.

  According to the present invention, an inexpensive fluororesin having the characteristics of a fluororesin (heat resistance, cold resistance, chemical resistance, mechanical characteristics, etc.), excellent conductivity such as conductivity and thermal conductivity, and electromagnetic wave absorption A molded object can be manufactured easily. Moreover, the said fluororesin molded object of this invention is excellent in the said characteristic.

FIG. 1 is a schematic cross-sectional view schematically showing the structure of the fluororesin molded body of the present invention. FIG. 2 is a schematic cross-sectional view schematically showing the structure of the fluororesin molded body obtained in Comparative Example 1.

Hereinafter, the present invention will be specifically described.
[Method for producing fluororesin molding]
The first production method of the fluororesin molded body of the present invention,
A mixture (ac-1) of a fluorine-containing polymer a for marine having a viscosity α of 10 ³ to 10 ⁷ P at a kneading temperature T _k and a functional filler c;
A fluorine-containing polymer for island part b having a higher viscosity β at the kneading temperature T _k than the viscosity α of the sea-part fluorine-containing polymer a;
Melt kneading at a temperature T _k that is at least a temperature T _ma at which the fluoropolymer a for sea part melts and lower than the decomposition temperatures T _da and T _{db of the} fluoropolymers a and b;
Compared to the fluorine-containing polymer b for islands, the functional filler c is dispersed at a higher concentration in the fluorine-containing polymer a for seas to prepare a melt-kneaded product (abc-1),
Next, this melt-kneaded product (abc-1) is molded to produce a fluororesin molded body having a sea-island structure.

Moreover, the 2nd manufacturing method of the fluororesin molding of this invention is as follows.
A fluorine-containing polymer a for sea part having a viscosity α of 10 ³ to 10 ⁷ P at a kneading temperature T _k ;
A functional filler c;
A fluorine-containing polymer for island part b having a higher viscosity β at the kneading temperature T _k than the viscosity α of the sea-part fluorine-containing polymer a;
Melt kneading at a temperature T _k that is at least a temperature T _ma at which the fluoropolymer a for sea part melts and lower than the decomposition temperatures T _da and T _{db of the} fluoropolymers a and b;
Compared with the fluorine-containing polymer b for islands, the functional filler c is dispersed at a higher concentration in the fluorine-containing polymer a for seas to prepare a melt-kneaded product (abc-2),
Next, this melt-kneaded product (abc-2) is molded to produce a fluororesin molded body having a sea-island structure.

In the present invention, between the melting temperatures (melting points) T _ma and T _mb , the kneading temperature T _k , and the decomposition temperatures T _da and T _db of these polymers a and b, T _ma <T _mb , T _k <T _da , It is preferable that there is a relationship of _Tdb . Further, at the kneading temperature T _{k of the} polymers a and b and the filler c, their viscosities α and β (P, Poise) have a relationship of β> α.

<Fluorine-containing polymer a for sea>
The marine fluoropolymer a used in the present invention has a viscosity (viscosity α) of 10 ³ to 10 ⁷ P (poise), preferably 10 ⁴ to 10 ⁵ P at a kneading temperature T _k (° C.) (200 to 400 ° C.). ) -Containing fluorine-containing polymer.

This sea part fluorine-containing polymer a constitutes the sea part (2) in the fluororesin molded body (1) shown in FIG.
Such a marine fluoropolymer a includes tetrafluoroethylene and the formula: CF ₂ = CF—O—R _f (wherein R _f is a fluoroalkyl group, preferably a C 1-10 fluoroalkyl group. Perfluoro (alkyl vinyl ether) {perfluoro (alkyl vinyl ether) represented by) may be used alone or in combination of two or more. } PFA [viscosity at 340 to 400 ° C., viscosity 10 ⁴ to 10 ⁵ P];
Tetrafluoroethylene / hexafluoropropylene copolymer [FEP, viscosity of 10 ⁴ to 10 ⁵ P at 310 to 370 ° C.];
Polychlorotrifluoroethylene [PCTFE, viscosity at 240 to 260 ° C., viscosity 10 ⁶ to 10 ⁷ P];
Polyvinylidene fluoride [PVDF, viscosity at 10 to 250 ° C., 10 ³ to 10 ⁴ P];
Ethylene / tetrafluoroethylene copolymer [ETFE, viscosity at 280 to 340 ° C., viscosity 10 ³ to 10 ⁴ P];
Etc.
(* Above, "Fluorine Resin Handbook" (editor Takaomi Satokawa, publisher Nikkan Kogyo Shimbun, first edition, 1st edition), page 396. The temperature shown is the general processing temperature described in the handbook, and the viscosity is the temperature range. Is shown in

  PFA that can be used in the present invention 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 perfluoro (alkyl vinyl ether) (provided that , The total amount of structural units of PFA is 100% by mass).

When the marine fluoropolymer a is PFA, it has a desired viscosity at the kneading temperature T _k , and has surface properties such as chemical resistance, heat resistance, non-adhesiveness, low friction, water and oil repellency, Excellent electrical and mechanical properties, combined with the properties of a thermoplastic resin that can be melt-molded, it can be processed freely, and these excellent properties can be used in a wide range of temperatures from extremely low to high temperatures. It is preferable because a fluororesin molded body capable of maintaining various characteristics can be produced.

The sea part fluorine-containing polymer a contains 20 to 80% by volume, preferably 25 to 75% by volume of the fluorine-containing polymer a in 100% by volume of the fluorine-containing polymer a and the fluorine-containing polymer b (a + b). It is desirable that
As a commercial item of such fluorine-containing polymer a for sea part, PFA940HP-Plus by Mitsui DuPont Fluorochemical Co., etc. can be mentioned, for example.

<Fluorine-containing polymer b for islands>
Fluoropolymer b for island used in the present invention, in the kneading temperature T _k, is a fluorine-containing polymer having a high viscosity β than the viscosity α in the above kneading temperature T _k of the sea part fluoropolymer a. The viscosity beta of islands for fluoropolymer b, in the kneading temperature _{T k, β / α ≧ 10} 2, preferably satisfy the relation of β / α ≧ 10 ^4, at a given temperature T _k, fluorine-containing resin molded article prepared When the components a, b and c for use are melt-kneaded (second production method) or the mixture ac-1 and the polymer b are melt-kneaded (first production method), the functional filler c is The high-concentration and uniform dispersion only in the fluorine-containing polymer a for the island, and the tendency to hardly exist in the fluorine-containing polymer b for the island portion remarkably appear, and as a result, the effect of the present invention as described above appears remarkably. In the present invention, however, the island-containing fluoropolymer b is 10 ⁵ to 10 ¹¹ P (poise), preferably 10 ⁷ to 10 ¹¹ P, more preferably 10 ¹⁰ to 10 ¹¹ P at the kneading temperature T _k . Fluorine-containing poly having a viscosity (viscosity β) Mer is preferred. This island portion fluoropolymer b constitutes the island portion (3) in the fluororesin molded body (1) shown in FIG.

In the fluororesin molded body of the present invention, by using the island-containing fluorine-containing polymer b having the above viscosity at the kneading temperature T _k , the sea-portion fluorine-containing polymer a has a higher content than the island-containing fluorine-containing polymer b. It is possible to disperse the functional filler c at a higher concentration.

As such a fluorine-containing polymer b for islands, polytetrafluoroethylene [PTFE, viscosity of about 1.0 × 10 ¹¹ P (poise) at 330 ° C.] is preferable, but other fluorine-containing polymers may be kneaded. Any fluororesin satisfying β / α ≧ 10 ² at the temperature T _k can be used as the fluoropolymer b of the present invention. For example, tetrafluoroethylene (CF ₂ = CF ₂ ), C _n F _{2n + 1} C = CF ₂ (n = 1-12), C _n F _{2n + 1} O [CF (CF ₃ ) CF ₂ O] mCF = CF ₂ (n = 1-5, m = 0-10), a copolymer with a comonomer such as ClCF = CF ₂ (PTFE copolymer resin), polychlorotrifluoroethylene [PCTFE, 240-260 Viscosity of 10 ⁶ to 10 ⁷ P] and the like can be mentioned. When a fluorine-containing polymer having a viscosity of 10 ⁹ P or less at a melt-kneading temperature T _k such as PCTFE is used as the fluorine-containing polymer b, β / α ≧ at the melt-kneading temperature T _k as the fluorine-containing polymer a. It is preferable to use a fluororesin satisfying 10 ² .

  In addition, the melting point of the island fluorine-containing polymer b represented by PTFE is higher than the melting point of the sea fluorine-containing polymer a represented by PFA, and the decomposition temperature of these fluorine-containing polymers a and b is fluorine-containing. It is preferably higher than the melting point temperature of the polymer a.

When the island-containing fluoropolymer b is PTFE, it has a desired viscosity at the kneading temperature T _k and has surface properties such as chemical resistance, heat resistance, non-adhesiveness, low friction, water repellency and oil repellency. It is preferable because of its excellent electrical and mechanical properties.

  Moreover, since PTFE has compatibility with the above-mentioned fluoropolymer a for sea part at a temperature equal to or higher than the melting point of PTFE, the obtained fluororesin molded body is preferable because it can have high strength.

  The island-containing fluorine-containing polymer b contains 20 to 80% by volume, preferably 25 to 75% by volume of the fluorine-containing polymer b in 100% by volume (a + b) of the fluorine-containing polymer a and the fluorine-containing polymer b. It is desirable that

  When the fluoropolymer b for islands is contained in the above amount in the fluororesin molding, the conductivity and electromagnetic wave absorption of the resulting fluororesin molding can be obtained even if the functional filler c is used in a relatively small amount. Can be improved.

Examples of the shape of the island portion fluoropolymer b used in the present invention include particulate and fibrous fluoropolymers.
The shape of the island portion fluorine-containing polymer b may be appropriately changed according to the desired shape of the fluororesin molded body, but in the case of a particle shape, the average particle diameter is 0.1 to 100 μm. It is preferable that Also, any of molding powder, fine powder, and dispersion can be used.

It is preferable that the island-containing fluorine-containing polymer b used in the present invention has the above-mentioned shape because a fluororesin molded body having excellent conductivity and electromagnetic wave absorption and high strength can be obtained.
Examples of such commercially available island-part fluoropolymer b include PTFE powder M12 manufactured by Daikin Industries, Ltd.

<Functional filler c>
The functional filler c used in the present invention is a filler for imparting heat conductivity, conductivity such as electric conductivity, and / or electromagnetic wave absorption to the fluororesin molded body, and is not particularly limited. However, the conductive filler, the heat conductive filler, and / or the electromagnetic wave absorbing filler can be increased, and can be appropriately changed depending on the use of the obtained fluororesin molding.

  Although it does not necessarily limit as an electroconductive filler which can be used by this invention, For example, a metal, an electroconductive metal oxide, a carbon material, a whisker etc. are mentioned, These are combined 1 type (s) or 2 or more types. Can be used.

Examples of the metal include gold, silver, copper, and aluminum.
Examples of the conductive metal oxide include zinc oxide, tin oxide, and indium oxide.

Examples of the carbon material include carbon black, carbon fiber, carbon nanotube, and carbon nanocoil.
As said whisker, a potassium titanate whisker etc. are mentioned, for example.

  Among them, carbon black is generally used as a functional filler because of its excellent electrical conductivity. Use this material because of its shape, cost, availability, and ease of handling. Is most desirable.

As the conductive filler, one kind may be used alone, or two or more kinds having different materials and characteristics may be used in combination.
As the heat conductive filler that can be used in the present invention, known heat conductive fillers used industrially can be used without limitation.

  Examples of such known thermally conductive fillers include graphite (graphite), carbon black, carbon fiber, carbon nanotube, carbon nanocoil, boron nitride, aluminum nitride, silicon nitride, alumina, magnesium oxide, beryllium oxide, titanium oxide, Zirconium oxide, zinc oxide, magnesium hydroxide, aluminum hydroxide, barium hydroxide, calcium hydroxide, aluminum powder, copper powder, iron powder, titanium carbide, boron carbide, aluminum carbide, silicon carbide, diamond, polymer film firing Then, a pulverized film pulverized product can be used. In particular, carbon black and graphite (graphite) are generally used as thermal conductive fillers because of their excellent thermal conductivity. This material is used because of its shape, cost, availability, and ease of handling. It is most desirable to use

  In addition, metal nitrides such as boron nitride and aluminum nitride, and metal hydroxides such as magnesium hydroxide, dispersibility in terms of being able to increase the flame retardance of sheets, in terms of insulation and high thermal conductivity However, magnesium oxide, alumina, and magnesium hydroxide are preferable.

A heat conductive filler may be used individually by 1 type, and may use it in combination of 2 or more types from which a material and a characteristic differ.
As the electromagnetic wave absorbing filler that can be used in the present invention, any one or more of conductive filler, dielectric filler, and magnetic filler can be used.

As such a conductive filler, the above-mentioned conductive filler can be used, and carbon black, graphite, carbon fiber, and ferrite are preferable.
Dielectric fillers include titanium dioxide, barium titanate, barium zirconate titanate, strontium titanate, calcium titanate, bismuth titanate, magnesium titanate, barium neodymium titanate, titanate Barium tin, barium magnesium niobate, barium magnesium tantalate, lead titanate, lead zirconate, lead zirconate titanate, lead niobate, lead magnesium niobate, lead nickel niobate, One or more fillers selected from lead tungstate, calcium tungstate, and lead magnesium tungstate can be used.

Although it does not necessarily limit as a magnetic filler, For example, a magnetic alloy metal (Sendust, permalloy) and a ferrite can be mentioned. Ferrite is a group of iron oxides having a composition of MO · Fe ₂ O ₃ , where M is a divalent metal ion, for example, Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ^{2. +} , Zn ²⁺ and the like. It can be obtained by mixing metal oxide and iron oxide powders, compression molding and firing. M is not limited to one kind, and various magnetic characteristics can be produced by mixing two or more kinds in combination to form a solid solution.

  As the functional filler c that can be used in the present invention, any of the above-mentioned fillers can be used. Among them, the use of carbon black is excellent in conductivity, thermal conductivity, and electromagnetic wave absorption. It is most desirable because of its shape, cost, availability, and ease of handling. A fluororesin molded body obtained by using carbon black as the filler c is preferable because it can be used for any of heat conduction, electric conduction, and electromagnetic wave absorption.

  The functional filler c has a blending amount of the functional filler c of 0.1 to 50% by volume, preferably 100% by volume (a + c) of the sea part fluorine-containing polymer a and the functional filler c. 1 to 30% by volume is desirable.

  If the blending amount of the functional filler c is in the above range, a fluororesin molded body having sufficient conductivity, electromagnetic wave absorption and high strength can be obtained, and the production of the fluororesin molded body is facilitated. preferable.

  In particular, in the present invention, since the functional filler c is unevenly distributed in the molded body, the amount used is higher than that of the filler used in the mixed material imparted with conductivity to the conventional resin as described above. Since a fluororesin molded body having sufficient conductivity can be obtained even in a small amount, it is preferable. Moreover, since the amount of filler that causes the strength deterioration of the molded body is small, the obtained molded body has high strength. Furthermore, when used in semiconductor-related equipment and electronic equipment, the amount of filler that becomes an impurity is small, so that the obtained molded body can be suitably used in fields where reduction of impurities is desired.

Examples of the shape of the functional filler c used in the present invention include particulate, fibrous, tubular, and fibrous fillers.
What is necessary is just to change suitably the shape of such a functional filler c according to the shape and use of a desired fluororesin molded object.

  When the functional filler c used in the present invention has the above shape, it becomes easy to disperse (unevenly) in the sea part fluorine-containing polymer a, and a fluororesin molded article having excellent conductivity and electromagnetic wave absorption can be obtained. preferable.

  Examples of such commercially available functional filler c include acetylene black (Denka Black) manufactured by Denki Kagaku Kogyo Co., Ltd., carbon fiber (Lahema) manufactured by Teijin Limited, and carbon fiber (VGCF) manufactured by Showa Denko K.K. it can.

<Method for producing fluororesin molding>
The first production method of the fluororesin molded body of the present invention is to knead the a, b and c components in the following two stages. In the first stage, the marine fluoropolymer a and the functional filler c In a second stage, this mixture (ac-1) and the island-containing fluoropolymer b are kneaded. That is,
A mixture (ac-1) of a fluorine-containing polymer a for marine having a viscosity α of 10 ³ to 10 ⁷ P at a kneading temperature T _k and a functional filler c;
A fluorine-containing polymer for island part b having a higher viscosity β at the kneading temperature T _k than the viscosity α of the sea-part fluorine-containing polymer a;
Melt kneading at a temperature T _k that is at least equal to or higher than the temperature at which the fluoropolymer a for sea part melts and lower than the decomposition temperature of the fluoropolymers a and b;
Compared to the fluorine-containing polymer b for islands, the functional filler c is dispersed at a higher concentration in the fluorine-containing polymer a for seas to prepare a melt-kneaded product (abc-1),
Next, this melt-kneaded product (abc-1) is formed.

Moreover, the 2nd manufacturing method of the fluororesin molding of this invention knead | mixes said a, b, c component in 1 step. That is,
A fluorine-containing polymer a for sea part having a viscosity α of 10 ³ to 10 ⁷ P at a kneading temperature T _k ;
A functional filler c;
A fluorine-containing polymer for island part b having a higher viscosity β at the kneading temperature T _k than the viscosity α of the sea-part fluorine-containing polymer a;
Melt kneading at a temperature T _k that is at least equal to or higher than the temperature at which the fluoropolymer a for sea part melts and lower than the decomposition temperature of the fluoropolymers a and b;
Compared with the fluorine-containing polymer b for islands, the functional filler c is dispersed at a higher concentration in the fluorine-containing polymer a for seas to prepare a melt-kneaded product (abc-2),
Next, this melt-kneaded product (abc-2) is formed.

In the present invention, in any of the first and second production methods, the melt kneading temperature T _k is _{equal to} the viscosity α of the sea part fluoropolymer a at the kneading temperature T _k , The viscosity β of the fluoropolymer b at the kneading temperature T _k is usually a temperature that satisfies the relationship β / α ≧ 10 ² , preferably a temperature that satisfies the relationship β / α ≧ 10 ^4. However, as shown in FIG. 1, a fluororesin molded body having a sea-island structure in which the functional filler c is unevenly distributed (existing) only in the sea part, and the functional filler c is substantially not present at all in the island part ( 1) is obtained, and is preferable because it is excellent in various properties such as conductivity as described above.

  In addition, the obtained fluororesin molded article has substantially physical properties in terms of conductivity such as conductivity and thermal conductivity corresponding to the type of filler, and electromagnetic wave absorption in both the first and second production methods. Almost no difference and good.

    In particular, in the first production method (two-stage production method), the functional filler c can be uniformly dispersed in the marine fluoropolymer a better than in the second production method (one-stage production method). In addition, the second manufacturing method (one-step manufacturing method) can obtain the fluororesin molding of the present invention in one step as compared to the first manufacturing method (two-step manufacturing method). It is excellent in that it is efficient.

  According to the method for producing a fluororesin molded body of the present invention, the fluoropolymers a and b and the functional filler c are kneaded under the condition that the two or more types of fluoropolymers a and b used have a predetermined viscosity difference. In order to produce a fluororesin molded body, the functional filler c is easily contained in the sea part fluorine-containing polymer a as compared with the island part fluoropolymer b. c can be dispersed at a higher concentration. That is, in the present invention, it is important to have a sufficient viscosity difference as described above when mixing (kneading) resins having different viscosities, that is, when kneading.

Therefore, according to the method for producing a fluororesin molded body of the present invention, a fluororesin molded body having excellent conductivity and electromagnetic wave absorbability can be obtained.
Further, in the molding stage, a fluororesin molded body having a desired shape can be easily produced.

  In the production method (I), the method of mixing the marine fluoropolymer a and the functional filler c is not particularly limited, but a known kneader such as a kneader, roll mill, intermix, or Banbury mixer is used. Depending on the type of polymer a, etc., it is usually higher than the melting temperature (melting point) of the marine fluoropolymer a to less than the decomposition temperature, and preferably about 10-30 ° C. higher than the melting temperature (melting point). ”To“ temperature lower by 10 to 20 ° C. than the decomposition temperature ”For example, in PFA, the mixture (ac-1) is produced by mixing at 310 to 340 ° C., preferably 320 to 340 ° C. for 1 to 60 minutes. be able to.

In the above production methods (I) and (II), the method for kneading the sea part fluorine-containing polymer a, the functional filler c, and the island part fluorine-containing polymer b is not particularly limited. The melt-kneaded product (abc-1) or (abc-2) can be prepared by kneading at a kneading temperature T _k for 1 to 60 minutes using a known kneader such as a mix or a Banbury mixer.

In the present invention, the kneading temperature T _k is a temperature at which the sea part fluorine-containing polymer a, the functional filler c, and the island part fluorine-containing polymer b, which are at least essential components, are kneaded together.

As the kneading temperature T _k , a temperature that is at least equal to or higher than the melting temperature of the sea part fluorine-containing polymer a and lower than the decomposition temperature of the sea part and island part fluoropolymers a and b is employed.

The specific kneading temperature T _k in the present invention varies depending on the types of the fluoropolymers a and b used. In the present invention, the viscosities α and β of the fluoropolymer a for the sea part and the fluoropolymer b for the island part are used. (P, Poise) is selected such that the types and molecular weights of the polymers a and b are such that β / α ≧ 10 ² , particularly preferably β / α ≧ 10 ^4, and the kneading temperature T _k is also selected. It is desirable that

Accordingly, the kneading temperature T _k satisfying such a viscosity ratio is usually not less than the melting temperature (melting point) of the marine fluoropolymer a and less than the decomposition temperature, preferably 10 to 30 from the melting temperature (melting point). It is about 200-400 degreeC, Preferably, it is 300-350 degreeC, for example, 200 degreeC lower than the decomposition temperature of the polymer a of a lower decomposition temperature.

By kneading the sea part fluorine-containing polymer a, the functional filler c, and the island part fluorine-containing polymer b at such a temperature T _k in one stage or two stages (preferably in a predetermined amount ratio). In addition, it is possible to efficiently and easily produce a fluororesin molded body having a sea-island structure and having excellent “conductivity” such as conductivity or thermal conductivity and electromagnetic wave absorption.

  In particular, when kneading at a temperature equal to or higher than the melting point of the fluoropolymers a and b and lower than the decomposition temperature of the fluoropolymers a and b, it is compatible at the interface of the fluoropolymer b having a high viscosity and has higher strength. The fluororesin molded body can be produced, which is preferable.

More specifically, PTFE shows highest melting point 327 ° C. and a high decomposition temperature (500 ° C.), the high viscosity (330 ° C. at a viscosity of 10 ¹¹ P, a viscosity of ¹⁰ at 380 ℃ 10 P~10 ¹¹ P) Therefore, PTFE is selected as the fluorine-containing polymer b, and when the viscosity at the kneading temperature T _k is β, the viscosity ratio β / α has a lower viscosity α than PTFE so that the viscosity ratio β / α is in the above range. When PFA is selected as the polymer a, the melting temperature (melting point) is 300 to 310 ° C., the decomposition temperature is 400 ° C., the viscosity is 10 ⁴ P to 10 ⁵ P at 380 ° C., and the viscosity is 10 ⁵ P at 330 ° C. Indicates.

From the above, the kneading temperature T _k when using PFA as the sea part fluoropolymer a and using PTFE as the island fluoropolymer b is 310 to 380 ° C., preferably 320 to 350 ° C. In the PTFE-PFA system, β / α> 10 ^{4 at the} kneading temperature T _k .

Such a PTFE-PFA system has particularly excellent mechanical, chemical, electrical and other properties among the fluorine-containing polymers, and β / α> 10 ^4. A fluororesin molded product that is more unevenly distributed in the sea is obtained, and is excellent in electrical conductivity, thermal conductivity, and electromagnetic wave absorption. Furthermore, PFA and PTFE are compatible at or above the melting point of PTFE. You can get a body.

  In the production method (I) or (II), the method for molding the melt-kneaded product (abc-1) or (abc-2) is not particularly limited. Examples thereof include injection molding or extrusion molding. When a fluororesin molded body is molded by such a molding method, a fluororesin molded body having a desired size and shape may be molded from the beginning, or a large molded body in advance using the above molding method. After molding, a fluororesin molded body having a desired size and shape can be produced by cutting into a desired size.

Conditions such as the temperature at the time of molding are not particularly limited, but usually, among the fluorine-containing polymers contained, the decomposition temperature of all the fluorine-containing polymers contained from the melting point of the lower melting point sea-containing fluorine-containing polymer a to The melting point of both the sea part fluoropolymer a and the island fluoropolymer b to the decomposition temperature or less, for example, the temperature is 200 to 400 ° C., the pressure is 50 to 400 kgf / cm ² , and the time is 1 It can be ˜60 minutes.

[Fluoropolymer molded product]
The fluororesin molded product of the present invention is a molded product having a sea-island structure.
Such a schematic cross-sectional view of an example of the fluororesin molded body of the present invention is schematically shown in FIG.

The fluororesin molded body (1) of the present invention shown in FIG. 1 has a functional filler c (4) in the sea part fluorine-containing polymer a (2) as compared with the island part fluoropolymer b (3). Is dispersed at a higher concentration. That is, the functional filler c (4) is unevenly distributed in the fluororesin molded body (1). This is because the functional filler c (4) is preferentially introduced (mixed / dispersed) into the fluorine-containing polymer a (2) having a low viscosity at the kneading temperature T _k , and the fluorine-containing polymer having a high viscosity. This is because the amount introduced into b (3) is very limited.

  In particular, in the fluororesin molded body of the present invention having such a structure, the functional filler c (4) may be unevenly distributed in the film thickness direction of the molded body (up and down direction on the paper surface). As shown in Fig. 2), the same amount of functional filler (7) is used, and the film thickness direction (vertical direction on the paper surface) is higher than that of a conventional molded body obtained by uniformly dispersing the filler in the molded body. Thus, a molded article having excellent conductivity such as heat and electricity and electromagnetic wave absorption can be obtained.

  As described above, the fluororesin molded body (1) of the present invention comprises the fluoropolymers a (2) and b (3) and the functional filler c (4), and the functional filler c (4) is the molded body. (1) In the polymer a (2) that constitutes the sea part, it is substantially unevenly distributed only in the polymer b (3) that constitutes the island part. Chemical properties, heat resistance, non-adhesiveness, low friction properties, water / oil repellency and other surface properties, electrical properties, and mechanical properties of polymers, and functional fillers with conductivity and electromagnetic wave absorption Even if the content of the expensive functional filler is small as compared with the conventional molded body composed of a resin and a functional filler, the molded body has higher conductivity and electromagnetic wave absorption than the conventional molded body. Moreover, even if the content of the functional filler is smaller than before, a fluororesin molded product having physical properties such as electrical conductivity and thermal conductivity equivalent to or higher than that of the conventional product can be obtained, and the content of fluororesin is conventionally increased. Therefore, the fluororesin molded body of the present invention is an inexpensive fluororesin molded body having excellent properties such as excellent strength and low generation of impurities derived from the filler.

Although the fluororesin molded body of this invention should just have a desired shape according to a use, shapes, such as a sheet | seat (film) shape, plate shape, rod shape, can be mentioned, for example.
When such a fluororesin molded product of the present invention has a low surface resistivity and a low volume resistivity and a high electrical conductivity, it makes use of the characteristics as a conductive material or has a high thermal conductivity. When it is a thing, it can be used as a heat conductive material, and when it is a thing with high electromagnetic wave absorptivity, it can be used as an electromagnetic wave absorptive material taking advantage of the characteristic.

  As the conductive material, for example, it can be used in various applications where the generation of static electricity should be prevented. As a specific example, it can be used in a food kneading roll, a transport chute / pipe / belt, a wafer basket that is a jig for storing a wafer when cleaning and drying a semiconductor wafer, and the like.

In the fluororesin molded body for electrical conduction (for conductive material),
The surface resistivity (Ω / □) of the fluororesin molded body (according to the four probe method) is 10 ⁰ to 10 ¹⁰ ,
The surface resistivity (Ω / □) (by the ring electrode method) is 10 ⁰ to 10 ¹⁰ ,
Volume resistivity (Ω · cm) (by four-probe method) is 10 ⁻¹ to 10 ⁹ ,
The volume resistivity (Ω · cm) (by the ring electrode method) is preferably 10 ⁻¹ to 10 ⁹ .
The fluororesin molded body of the present invention can be suitably used for electrical conduction because both the surface resistivity and the volume resistivity are particularly low.

In addition, as a heat conductive material, for example, by interposing between a heat generator such as an electronic component and a heat sink such as a heat sink or a heat pipe, it is suitable for effective heat conduction between the two. Yes. Examples of the covering object include a mobile notebook personal computer, a mobile phone, and a circuit board.
In the fluororesin molded body for heat conduction (for heat conductive material), the heat conductivity is usually 0.5 W / m · K to 3 W / m · K, preferably 0.7 W / m · K to 2 W / m · K.

  As an electromagnetic wave absorbing material, for example, for the purpose of suppressing interference of electromagnetic waves generated by currents flowing in various wirings inside electronic devices such as personal computers and mobile phones, and suppressing the radiation of electron waves from electronic devices. It can be used by sticking to a device or a component inside the device.

[Example]
EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.

[Example 1]
Kneader of PFA (10 ⁵ P (330 ° C.), Mitsui DuPont Fluorochemicals, 940HP-Plus) and carbon black (CB, acetylene black, Denki Kagaku Kogyo, Denka Black) at a volume ratio of 75:25. (Toyo Seiki Co., Ltd., Lab Plast Mill) was used and mixed at 330 ° C. for 10 minutes (Material A).

The material A and PTFE (10 ¹¹ P (330 ° C.), Daikin Industries, M12) were mixed at 330 ° C. (T _k) using the above kneader so that material A: PTFE = 50: 50 (volume%). And kneaded at 350 ° C. for 60 minutes, and then placed in a mold and kept at room temperature (25 ° C.) at a pressure of 200 kgf / cm ² for 10 minutes. The mold was formed into a shape of 50 × 0.5 ^t mm.

[Example 2]
A fluororesin molded body was formed in the same manner as in Example 1 except that the kneading ratio of PFA (940HP-Plus), carbon black (CB) and PTFE (M12) was changed as shown in Table 1.

[Example 3]
PFA (10 ⁵ P (330 ° C), Mitsui DuPont Fluorochemicals, 940HP-Plus) and carbon black (CB, acetylene black, Denki Black, Denka Black) and PTFE (10 ¹¹ P (330 ° C), Daikin Industries, Ltd., M12) was kneaded for 10 minutes at 330 ° C. (T _k ) using a kneader (Toyo Seiki, Labo Plast Mill) at a volume ratio of 37:13:50, and this kneaded product After being melted by heating at 350 ° C. for 60 minutes, it is placed in a mold and kept at a normal temperature of 25 ° C. and a pressure of 200 kgf / cm ² for 10 minutes to form a mold of 50 × 50 × 0.5 ^t mm. did.

[Example 4]
A fluororesin molded body was formed in the same manner as in Example 3 except that the kneading ratio of PFA (940HP-Plus), carbon black (CB), and PTFE (M12) was changed as shown in Table 1.

[Example 5]
FEP (10 ⁴ P (300 ° C.), manufactured by Daikin Industries, NP-20) and carbon black (CB, acetylene black, manufactured by Denki Kagaku Co., Ltd., Denka Black) at a volume ratio of 39:11 kneader (Toyo (Made by Seiki Co., Ltd., Lab Plast Mill) was mixed at 300 ° C. for 10 minutes (Material A).

This material A and PTFE (10 ¹¹ P (330 ° C.), Daikin Industries, Ltd., M12) are mixed at 300 ° C. (T _k) using the kneader so that the material A: PTFE = 50: 50 (volume%). And kneaded at 350 ° C. for 60 minutes, and then put in a mold and kept at room temperature (25 ° C.) at a pressure of 200 kgf / cm ² for 10 minutes, 50 × A molded body of 50 × 0.5 ^t mm was produced.

[Example 6]
A fluororesin molded body was formed in the same manner as in Example 5, except that the kneading ratio of FEP (NP-20), carbon black (CB) and PTFE (M12) was changed as shown in Table 2.

[Example 7]
FEP (10 ⁴ P (300 ° C.), Daikin Industries, NP-20) and carbon black (CB, acetylene black, Denka Black, Denka Black) and PCTFE (10 ⁶ P (300 ° C.), Daikin Industries M-300) was kneaded for 10 minutes at 300 ° C. (T _k ) using a kneader (Toyo Seiki, Labo Plast Mill) at a volume ratio of 39:11:50, and this kneaded product After being melted by heating at 300 ° C. for 60 minutes, it was placed in a mold and held at a normal temperature of 25 ° C. and a pressure of 6 MPa for 10 minutes to mold into a shape of 50 × 50 × 0.5 ^t mm.

[Comparative Examples 1 and 2]
A fluororesin molded body was formed in the same manner as in Example 1 except that the kneading ratio of PFA (940HP-Plus) and carbon black (CB) was changed as shown in Table 1.

[Comparative Examples 3 and 4]
A fluororesin molded body was formed in the same manner as in Example 5 except that the kneading ratio of FEP (NP-20) and carbon black (CB) was changed as shown in Table 2.

[Comparative Example 5]
FEP (10 ⁴ P (330 ° C.), Daikin Industries, NP-20) and carbon black (CB, acetylene black, Denki Black, Denka Black) and PFA (10 ⁵ P (330 ° C.), Mitsui DuPont) 940HP-Plus, manufactured by Fluorochemical Co., Ltd., and kneaded at 330 ° C. (T _k ) for 10 minutes using a kneader (Toyo Seiki Co., Ltd., Labo Plast Mill) at a volume ratio of 39:11:50. The kneaded material was heated and melted at 345 ° C. for 60 minutes, then placed in a mold and held at room temperature at 25 ° C. and a pressure of 6 MPa for 10 minutes, and molded into a 50 × 50 × 0.5 ^t mm shape. .

(Evaluation of molded body)
The molded bodies produced in Examples 1 to 7 and Comparative Examples 1 to 5 were subjected to surface resistance by the double ring electrode method (ASTM D257, manufactured by Toa DKK Corporation) and the four probe method (JIS K 7194, manufactured by Mitsubishi Chemical Corporation). Rate and volume resistivity were measured respectively.
The results are shown in Tables 1 and 2.

(result)
Also when the molded body was manufactured by kneading in one stage (Examples 1 and 2), the electrical resistivity showed the same value as when the molded body was manufactured by kneading in two stages (Examples 3 and 4). This indicates that a molded body in which carbon black is unevenly distributed can be obtained equally in the first manufacturing method and the second manufacturing method.

  (I) Examples 1 and 3 and Comparative Example 1, (ii) Examples 2 and 4 and Comparative Example 2, (iii) Example 5 and Comparative Example 3, and (iv) Example 6 and Comparative Example 4, respectively. The volume% of carbon black which is a conductive material in the obtained fluororesin molded body was the same, and the volume resistivity and the surface resistivity of (i) to (iv) showed similar values. That is, it is a feature of the present invention that there is no large difference in resistivity between the comparative example having a large amount of CB and the embodiment having a CB amount that is half that amount. In order to obtain the same resistivity, the structure of the embodiment ( This means that a smaller amount of CB is sufficient. This is because the amounts of carbon black used in the fluororesin molded bodies obtained in Examples 1 and 3 and Comparative Example 2 were the same, but the molded bodies of Examples 1 and 3 in which carbon black was unevenly distributed were used. Compared with the molded body of Comparative Example 1 which is simply composed of PFA and carbon black, the carbon black is uniformly dispersed, and is not unevenly distributed, both the surface resistivity and the volume resistivity are lower in any measurement method. It is clear from the rate. Similar results could be found even when PFA was changed to FEP (the molded body of Example 5 and the molded body of Comparative Example 4).

When the melt viscosity α, β (Poise, β> α) of the fluoropolymers a, b satisfies the relationship β / α ≧ 10 ^{2 at} the melt kneading temperature T _k (Examples 1 to 7), the function The filler was unevenly distributed in the fluorine-containing polymer having a lower melt viscosity (α) at the melt kneading temperature T _k , and both the surface resistivity and the volume resistivity showed low resistivity in any measurement method.

On the other hand, at the melt-kneading temperature T _k , the melt viscosity α, β (Poise, β> α) of the fluoropolymers a, b does not satisfy the relationship β / α ≧ 10 ² (Comparative Example 5, β / α = 10 ¹ ), the functional filler was dispersed in the fluororesin molded body, and both the surface resistivity and the volume resistivity showed high resistivity in any measurement method.

  According to the method for producing a fluororesin molded body of the present invention, it is shown that a fluororesin molded body with improved electrical conductivity could be obtained even when the amount of filler used was small.

1: Fluororesin molded product showing one embodiment of the present invention 2: Fluorine-containing polymer a for sea area, (PFA)
3: Fluorine-containing polymer for island part b, (PTFE)
4: Functional filler (carbon black (acetylene black))
5: Molded body obtained in Comparative Example 1 6: PFA
7: Carbon black (acetylene black)

Claims (9)

A mixture (ac-1) of a fluorine-containing polymer a for marine having a viscosity α of 10 ³ to 10 ⁷ P at a kneading temperature T _k and a functional filler c;
A fluorine-containing polymer for island part b having a higher viscosity β at the kneading temperature T _k than the viscosity α of the sea-part fluorine-containing polymer a;
Melting and kneading at a temperature T _k that is at least equal to or higher than the melting temperature of the fluoropolymer a for sea and lower than the decomposition temperature of the fluoropolymers a and b,
Compared to the fluorine-containing polymer b for islands, the functional filler c is dispersed at a higher concentration in the fluorine-containing polymer a for seas to prepare a melt-kneaded product (abc-1),
Then, this melt-kneaded material (abc-1) is shape | molded, The manufacturing method of the fluororesin molded object which has a sea island structure characterized by the above-mentioned. A fluorine-containing polymer a for sea part having a viscosity α of 10 ³ to 10 ⁷ P at a kneading temperature T _k ;
A functional filler c;
A fluorine-containing polymer for island part b having a higher viscosity β at the kneading temperature T _k than the viscosity α of the sea-part fluorine-containing polymer a;
Melting and kneading at a temperature T _k that is at least equal to or higher than the melting temperature of the fluoropolymer a for sea and lower than the decomposition temperature of the fluoropolymers a and b,
Compared with the fluorine-containing polymer b for islands, the functional filler c is dispersed at a higher concentration in the fluorine-containing polymer a for seas to prepare a melt-kneaded product (abc-2),
Then, the manufacturing method of the fluororesin molding which has a sea-island structure characterized by shape | molding this melt-kneaded material (abc-2). The melt kneading temperature T _k is the viscosity α (poise) at the kneading temperature T _k of the sea part fluoropolymer a and the viscosity β (poise) at the kneading temperature T _k of the island fluoropolymer b. Is a temperature satisfying the relationship of β / α ≧ 10 ^2. The method for producing a fluororesin molded body according to claim 1 or 2, wherein   The method for producing a fluororesin molded body according to any one of claims 1 to 3, wherein the sea part fluoropolymer a is PFA and the island fluoropolymer b is PTFE.   The method for producing a fluororesin molded body according to any one of claims 1 to 4, wherein the functional filler c is carbon black.   The compounding quantity of the functional filler c in the total (a + c) 100 volume% of the fluoropolymer a for sea part and the functional filler c is 0.1 to 50 volume%. The manufacturing method of the fluororesin molded object in any one of.   The island-containing fluoropolymer b is used in an amount of 25 to 75% by volume based on 100% by volume (a + b) of the sea-part containing polymer a and the island-containing fluoropolymer b. The manufacturing method of the fluororesin molded object in any one of Claims 1-6.   A fluororesin molded article obtained by the production method according to claim 1.   The fluororesin molded body according to claim 8, wherein the fluororesin molded body is used for heat conduction, electrical conduction, or electromagnetic wave absorption.