EP1948733A1 - Fluoropolymer composition for melt processing - Google Patents

Fluoropolymer composition for melt processing

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Publication number
EP1948733A1
EP1948733A1 EP06837041A EP06837041A EP1948733A1 EP 1948733 A1 EP1948733 A1 EP 1948733A1 EP 06837041 A EP06837041 A EP 06837041A EP 06837041 A EP06837041 A EP 06837041A EP 1948733 A1 EP1948733 A1 EP 1948733A1
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EP
European Patent Office
Prior art keywords
composition
ptfe
melt
pfa
ranges
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06837041A
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German (de)
French (fr)
Inventor
Shinichi Namura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chemours Mitsui Fluoroproducts Co Ltd
Original Assignee
Du Pont Mitsui Fluorochemicals Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Du Pont Mitsui Fluorochemicals Co Ltd filed Critical Du Pont Mitsui Fluorochemicals Co Ltd
Publication of EP1948733A1 publication Critical patent/EP1948733A1/en
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L27/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers
    • C08L27/02—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment
    • C08L27/12—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a halogen; Compositions of derivatives of such polymers not modified by chemical after-treatment containing fluorine atoms
    • C08L27/18—Homopolymers or copolymers or tetrafluoroethene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2205/00—Polymer mixtures characterised by other features
    • C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend

Definitions

  • the present invention pertains to a fluoropolymer composition for melt processing having excellent resistance to chemical permeation.
  • PFA the copolymer of tetrafluoroethylene (TFE) and perfluoro(alkyl vinyl ether) (PAVE) has excellent resistance to heat and chemicals.
  • PFA is used for melt molding of articles such as pipes for transporting various types of chemical solutions, fitting of the pipes, in making or lining pipes, fittings, valves, transportation containers, storage containers, pumps, and filter housings used in the pharmaceutical industry, and in other processes such as chemical plants, and semiconductor manufacturing process or liquid crystal manufacturing process; and for lining of articles such as steel pipes, valves and fittings.
  • PFA is exposed to highly permeable chemicals such as sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid, ammonia, their mixtures with hydrogen peroxide or ozone, developing or peeling solutions for photoresist to which a fluorinated surfactant is added, high-concentration ozone vapor, and ozone water.
  • highly permeable chemicals such as sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid, ammonia, their mixtures with hydrogen peroxide or ozone, developing or peeling solutions for photoresist to which a fluorinated surfactant is added, high-concentration ozone vapor, and ozone water.
  • PFA having high durability, as measured by flex life (sometimes called MlT flex life) and improved resistance to chemical permeation is desired.
  • Nitrogen gas permeability is ordinarily used as a convenient measure to evaluate the permeability of PFA.
  • Patent No. 6,649,699 the permeation resistance of PFA is improved, by blending PFA with polytetrafluoroethylene (PTFE) having low molecular weight. It is reported that the permeation resistance is improved with the increase of the PTFE mixture ratio.
  • the low molecular weight PTFE is eith'era 1 MIIH ' lowabli 1 PTFE directly obtained by the polymerization of the
  • PTFE or a PTFE which is obtained by the thermal decomposition or radiolysis of high molecular weight (non-melt processible) PTFE.
  • the low molecular weight PTFE obtained by direct polymerization is preferably blended with PFA because it is less costly, than the low molecular weight PTFE obtained by special treatments such as radiolysis, and furthermore has excellent thermal stability, and is more easily obtained in high purity, it is preferable for blending with the PFA.
  • the amount of the blended PTFE is increased to a level of 20% or greater of the PFA plus PTFE composition, the improvement of the permeation resistance of the composition does not increase in proportion to the increase of the PTFE content.
  • the purpose of the present invention is to provide an improved composition composed of PFA and a melt-flowable PTFE directly obtained by the polymerization having improved resistance to chemical permeation.
  • the fluoropolymer composition for melt processing of the present invention is composed of three components of (A) PFA, (B) melt-flowable PTFE directly obtained by polymerizing TFE, and (C) PTFE with a low molecular weight obtained by the radiolysis of a non-melt flowable high molecular weight PTFE.
  • the weight ratio of AJ(B + C) ranges from 80/20 to 30/70, and the weight ratio of (A + B)/C ranges from 99.99/0.01 to 90/10.
  • the composition of the present invention has improved permeation resistance, compared with a composition composed of two components of PFA (A) and PTFE.
  • Figure 1 shows the apparatus used in a hydrochloric acid permeation test.
  • the PFA (A) of the present invention is a copolymer of TFE and PAVE that can be manufactured by conventional methods such as solution polymerization, emulsion polymerization, or suspension polymerization.
  • PAVE used in the copolymer can be that of Formula 1 or 2. Examples include copolymers of TFE with perfluoro(methyl vinyl ether) (PMVE). This polymer, sometimes referred to as MFA, usually includes some PPVE in addition to PMVE.
  • Preferred comonomers are perfluoro(propyl vinyl ether) (PPVE) and perfluoro(ethyl vinyl ether) (PEVE), of which the PEVE is the more preferred comonomer. (Formula 1)
  • X is H or F.
  • n is an integer of 0 to 4.
  • m is an integer of 0 to 7.
  • CF 3 CF 3 q is an integer of 0 to 3.
  • the PAVE content in the PFA (A) is preferably 3 wt% or greater of the total wt % of PFA. If the content is less than 3 wt%, the durability of the composition obtained by mixing PTFE is unsatisfactory.
  • the lower limit of the PAVE content is preferably 5 wt% of the total PFA wt %. In general, with the increase of the content, the durability of the composition is improved.
  • high-temperature mechanical properties of the molded » " ⁇ " ⁇ pro ⁇ iict ⁇ etfer ' ioratiV-TH'e-lbreferable upper limit of the PAVE content is 15 wt%, and more preferably 10 wt% of the total PFA wt%.
  • the PFA (A) used in the present invention it is preferable for the PFA (A) used in the present invention to have a melt flow rate (hereinafter, abbreviated to MFR) of 0.01 g/10 min or 5 greater.
  • MFR melt flow rate
  • the preferred lower limit of the MFR is 0.05 g/10 min.
  • the upper limit of the MFR that can maintain a good durability is 100 g/10 min, preferably 70 g/10 min, and more preferably 40
  • PFA with an MFR of less than 0.01 g/10 min and PFA with an MFR of greater than 0.01 g/10 min can also be mixed to adjust the MFR between the above-mentioned upper limit and lower limit.
  • the PTFE (B) and the PTFE (C) are mixed with the above-mentioned PFA (A). Both the PTFE (B) and (C) are TFE
  • the PTFE (B) is a melt-flowable PTFE (that is, the melt flow rate can be measured by the method described in the Examples) directly
  • the MFR is not particularly limited but is usually selected from a range of 1 ,000
  • PTFE (B) can be manufactured by conventional methods such as solvent polymerization, emulsion polymerization, and suspension polymerization of TFE.
  • solvent polymerization emulsion polymerization
  • emulsion polymerization emulsion polymerization
  • suspension polymerization emulsion polymerization
  • PTFE (C) is a PTFE with a low molecular weight obtained by radiolysis of a non-melt flowable PTFE of high molecular weight.
  • Such non-melt flowable PTFE is often called "molding powder" or "fine powder.” Since the melt flowablity increases with decreasing molecular weight of the PTFE, the extent of decrease of the molecular weight can be , , om MFR of the PTFE as a function of degree of irradiation.
  • the PTFE (C) in the present invention has an MFR of 0.01 g/10 min or greater, and preferably 0.1 g/10 min or greater. If the MFR is less than 0.01 g/10 min, uniform dispersion of the PTFE in the composition is difficult.
  • the upper limit of the MFR is not particularly limited but is preferably in the range of 1 ,000 g/10 min or less.
  • the PTFE (C) can be manufactured by irradiation with gamma rays or an electron beam of the above-mentioned "molding powder” or "fine powder” at a temperature lower than the melting temperature under vacuum or in air or in an inert gas atmosphere until the radiation dose reaches 10 kGy-1 MGy.
  • the reaction is disclosed in Japanese Kokoku Patent Nos. Sho 47[1972]- 19609, Sho 52[1977]-38870, and GB 1 ,406,238.
  • the size of the PTFE (B) and the PTFE (C) particles are not particularly limited, and a powder with an average particle diameter of 0.01-100 ⁇ m can be used. A uniform composition is more easily obtained if the average particle diameter is preferably 0.05-50 ⁇ m, and more preferably 0.05-25 ⁇ m.
  • the above-mentioned PFA (A), PTFE (B), and PTFE (C) of the composition of the present invention are mixed in the weight ratio of A/(B + C) ranging from 80/20 to 30/70, and preferably ranging from 80/20 to 40/60, and more preferably ranging from 80/20 to 50/50. If the content of (B + C) is less than 20 wt%, the improvement of the permeation resistance is small, and if the content is more than 70 wt%, durability and mechanical strength of the composition decrease.
  • the composition of the present invention in which the PTFE component is composed of (B) and (C) has a permeation resistance improved by 20% or more compared to the permeation of PFA itself.
  • the ratio (A + B ) to C is in the range of 99.99/0.01 to 90/10 as the weight ratio of the PTFE (C), a sufficient improvement effect is obtained. If the ratio is less than 0.01 wt%, significant improvement in permeation resistance is not observed. The mixture ratio of more than 10 wt% tends to decrease the durability of the composition.
  • the (A + B)/C weight ratio is preferably 99.9/0.1 to 95/5, and more preferably 99/1 to 95/5. , mpoa ⁇ d of the above-mentioned PFA (A),
  • PTFE (B) 1 and PTFE (C) of the present invention can be melt processed and has an MFR of 0.1-100 g/10 min. If the MFR is less than 0.1 g/10 min, melt processing is difficult. If it is more than 100 g/10 min, the durability of the composition is unsatisfactory.
  • the MFR is preferably 0.5- 50 g/10 min.
  • the MFR of the composition can be estimated using the following equation.
  • (1/MFR of the composition) 1734 (weight % of PFA (A)) (1/MFR of PFA (A)) 1734 + (weight % of PTFE (B)) (1/MFR of PTFE (B)) 1734 + (weight % of PTFE (C)) (1/MFR of PTFE (C)) 1/34 .
  • the MFR of the composition sometimes deviates slightly from the numerical value obtained using the above-mentioned relation equation because of thermal decomposition or coupling phenomenon of the polymers during mixing or such post-treatments as fluorination
  • the MFR of the PFA (A), the PTFE (B), and the PTFE (C) can be estimated by taking this variation into consideration so that the MFR of the final composition will be in the desired range.
  • the PTFE In the manufacture of the composition of the present invention, if the PTFE is not well mixed, durability of articles made from the composition will be reduced. Therefore it is preferable to charge the PFA (A), the PTFE (B), and the PTFE (C) into a batch type or continuous kneader or coaxial extruder and to uniformly melt-knead the ingredients.
  • the PFA and PTFE powders can also be mixed in advance by dry or wet blending before melt-kneading. By wet blending is meant the mixing of dispersions of the PFA and one or both of the PTFEs.
  • These dispersions may be the dispersions obtained by aqueous dispersion polymerization of PFA and the PTFE made by polymerizing TFE to the desired low molecular weight, or the dispersions may be made from the polymer in powder form by dispersing the powder in preferably aqueous medium with a dispersing agent, such as a surfactant. After blending, the polymers are isolated from the dispersion medium.
  • a dispersing agent such as a surfactant
  • the mixture can be obtained by adding the PTFE (B) and PTFE (C) to a polymerization medium in a polymerization vessel in a ⁇ ro n ⁇ l & polym ⁇ rizatlon of TFE and PAVE to make PFA (A).
  • the PTFE (C) can be mixed with a powder of core/shell construction, which is obtained by adding particles of the PFA (A) to a polymerization medium in advance and initiating polymerization of the PTFE (B).
  • the PFA and the PTFE are preferably fluorinated before or after melt-kneading by the method described in U.S. Patent No. 4,743,658 and thereby reduce unstable end groups, to reduce the elution of fluorine ions, or to the improve the ozone resistance of articles made from the composition.
  • an improved resistance to chemical permeation can be obtained by mixing only a small amount of the higher cost PTFE (C) in addition to the PTFE (B), so that the cost penalty is minimized.
  • the PTFE has excellent heat resistance, chemical resistance, and purity similarly to that of the PFA, the composition of the present invention is suitable for a melt fabrication of parts for transferring various chemical solutions used in manufacturing processes of products such as chemicals, semiconductors and liquid crystal polymers.
  • Examples of articles made from the composition of the present invention include tubes, pipes, hoses, films, sheets, round bars, and square rods by extrusion; moldings, fittings, filter housings, valves, pumps, containers, wafer carriers, vessels, tanks, flow meters by injection molding; containers such as bottles by blow molding or rotation molding; lining of valves, pumps, pipes, joints, by transfer molding; lining of steel, such as steel containers, tanks, pipes, by rotation molding; and sheets, by compression molding.
  • PAVE content A sample was melt compressed at 350 0 C and cooled with water, so that a film with a thickness of about 50 ⁇ m was obtained. From the infrared absorption spectrum (in nitrogen atmosphere) of the film, the 1 . . , ,. " ra Vf "Content was ⁇ ' etermined according to the method described in U.S.
  • Melt flow rate (MFR): Using a melt indexer (made by Toyo Seiki Co., Ltd.) equipped with corrosion-resistant cylinder, die, and piston according to ASTM D1238-95, a 5 g sample was filled in the cylinder held at 372 ⁇ 1 0 C.
  • the sample was held for 5 min, and extruded through the die orifice under a load (piston and weight) of 5 kg.
  • the extrusion rate of the melt was measured and reported as the MFR.
  • Nitrogen gas permeability A film with a thickness of 0.25-0.35 mm prepared by a compression molding at 350 0 C was used for measuring the permeability at a temperature of 23 0 C by an S-69 type gas and water vapor permeability measurement device made by Shibata Kagaku Kikai
  • the above ingredients were blended by melt-kneading them at
  • compositions are obtained by melt- kneading similarly to Example 1.
  • the properties of the compositions are summarized in Table II. As in Table 1 , there is a large synergistic effect of
  • Amount mixed PFA 40 40 (part by weight) PTFE (B) 60 58.5 PTFE (C) 0 1.5

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Abstract

A composition having excellent resistance to chemical permeation, comprising (A) a tetrafluoroethylene-perfluoro(alkyl vinyl ether) copolymer, (B) a melt-flowable polytetrafluoroethylene directly obtained by the polymerization of tetrafluoroethylene, and (C) a polytetrafluoroethylene with a low molecular weight obtained by the radiolysis of a non-melt flowable polytetrafluoroethylene with a high molecular weight; the weight ratio of A/(B + C) is 80/20 to 30/70; and the weight ratio of (A + B)/C is 99.99/0.01 to 90/10.

Description

,.(
TITLE OF INVENTION
FLUOROPOLYMER COMPOSITION FOR MELT PROCESSING
FIELD OF INVENTION The present invention pertains to a fluoropolymer composition for melt processing having excellent resistance to chemical permeation.
BACKGROUND OF THE INVENTION
PFA, the copolymer of tetrafluoroethylene (TFE) and perfluoro(alkyl vinyl ether) (PAVE) has excellent resistance to heat and chemicals. PFA is used for melt molding of articles such as pipes for transporting various types of chemical solutions, fitting of the pipes, in making or lining pipes, fittings, valves, transportation containers, storage containers, pumps, and filter housings used in the pharmaceutical industry, and in other processes such as chemical plants, and semiconductor manufacturing process or liquid crystal manufacturing process; and for lining of articles such as steel pipes, valves and fittings.
In these applications, PFA is exposed to highly permeable chemicals such as sulfuric acid, hydrochloric acid, hydrofluoric acid, nitric acid, ammonia, their mixtures with hydrogen peroxide or ozone, developing or peeling solutions for photoresist to which a fluorinated surfactant is added, high-concentration ozone vapor, and ozone water. To suppress the corrosion of the equipment and the generation of cracks of molded articles due to permeation of these chemicals, PFA having high durability, as measured by flex life (sometimes called MlT flex life) and improved resistance to chemical permeation is desired. Nitrogen gas permeability is ordinarily used as a convenient measure to evaluate the permeability of PFA. Typical permeability of commercial PFA to nitrogen gas has been 0.8-1.2 x 10'10 cm3 (STP) ■ cm/cm2 ■ sec ■ cmHg. In Japanese Kokai Patent Application No. 2002-167488 U.S.
Patent No. 6,649,699, the permeation resistance of PFA is improved, by blending PFA with polytetrafluoroethylene (PTFE) having low molecular weight. It is reported that the permeation resistance is improved with the increase of the PTFE mixture ratio. The low molecular weight PTFE is eith'era1 MIIH'lowabli 1PTFE directly obtained by the polymerization of the
PTFE, or a PTFE which is obtained by the thermal decomposition or radiolysis of high molecular weight (non-melt processible) PTFE. In particular, since the low molecular weight PTFE obtained by direct polymerization is preferably blended with PFA because it is less costly, than the low molecular weight PTFE obtained by special treatments such as radiolysis, and furthermore has excellent thermal stability, and is more easily obtained in high purity, it is preferable for blending with the PFA. However, even if the amount of the blended PTFE is increased to a level of 20% or greater of the PFA plus PTFE composition, the improvement of the permeation resistance of the composition does not increase in proportion to the increase of the PTFE content. The purpose of the present invention is to provide an improved composition composed of PFA and a melt-flowable PTFE directly obtained by the polymerization having improved resistance to chemical permeation.
SUMMARY OF THE INVENTION
The fluoropolymer composition for melt processing of the present invention is composed of three components of (A) PFA, (B) melt-flowable PTFE directly obtained by polymerizing TFE, and (C) PTFE with a low molecular weight obtained by the radiolysis of a non-melt flowable high molecular weight PTFE. The weight ratio of AJ(B + C) ranges from 80/20 to 30/70, and the weight ratio of (A + B)/C ranges from 99.99/0.01 to 90/10. The composition of the present invention has improved permeation resistance, compared with a composition composed of two components of PFA (A) and PTFE. It is found surprisingly that there is a synergistic effect of PTFE (B) and PTFE (C), that is greater than the effect of either type of PTFE alone in a blend with PFA. Furthermore, small amounts of PTFE (C) as compared to PTFE (B) are effective in reducing permeability. PFA (A) and PTFE (B) even with small amounts of PTFE (C), have low nitrogen gas permeability of 0.7 x 10~10 cm3 (STP) ■ cm/cm2 'sec ■ cm Hg or less, compared with commercial PFA. g PlESCRIPTION OF THE FIGURE
Figure 1 shows the apparatus used in a hydrochloric acid permeation test.
DETAILED DESCRIPTION OF THE INVENTION
The PFA (A) of the present invention is a copolymer of TFE and PAVE that can be manufactured by conventional methods such as solution polymerization, emulsion polymerization, or suspension polymerization. PAVE used in the copolymer can be that of Formula 1 or 2. Examples include copolymers of TFE with perfluoro(methyl vinyl ether) (PMVE). This polymer, sometimes referred to as MFA, usually includes some PPVE in addition to PMVE. Preferred comonomers are perfluoro(propyl vinyl ether) (PPVE) and perfluoro(ethyl vinyl ether) (PEVE), of which the PEVE is the more preferred comonomer. (Formula 1)
Formula 1 : CF2=CF(OCF2CF)n-O-(CF2)mCF2X
I
CF3
X is H or F. n is an integer of 0 to 4. m is an integer of 0 to 7.
(Formula 2)
Formula 2: CF2=CF(OCF2CF)q-O-CF2CFCF3 I I
CF3 CF3 q is an integer of 0 to 3.
In the present invention, the PAVE content in the PFA (A) is preferably 3 wt% or greater of the total wt % of PFA. If the content is less than 3 wt%, the durability of the composition obtained by mixing PTFE is unsatisfactory. The lower limit of the PAVE content is preferably 5 wt% of the total PFA wt %. In general, with the increase of the content, the durability of the composition is improved. If the PAVE content is greater than 20 wt%, high-temperature mechanical properties of the molded » "■"■ proαiict αetfer'ioratiV-TH'e-lbreferable upper limit of the PAVE content is 15 wt%, and more preferably 10 wt% of the total PFA wt%.
It is preferable for the PFA (A) used in the present invention to have a melt flow rate (hereinafter, abbreviated to MFR) of 0.01 g/10 min or 5 greater. The lower the MFR, the greater the durability of articles made from the composition. If the MFR is less than 0.01 g/10 min, it is difficult to melt-process the composition. The preferred lower limit of the MFR is 0.05 g/10 min. The upper limit of the MFR that can maintain a good durability is 100 g/10 min, preferably 70 g/10 min, and more preferably 40
10 g/10 min. PFA with an MFR of less than 0.01 g/10 min and PFA with an MFR of greater than 0.01 g/10 min can also be mixed to adjust the MFR between the above-mentioned upper limit and lower limit.
In the present invention, the PTFE (B) and the PTFE (C) are mixed with the above-mentioned PFA (A). Both the PTFE (B) and (C) are TFE
15 homopolymer or a modified PTFE containing 1 wt% or less of a comonomer such as hexafluoropropylene, perfluoro(alkyl vinyl ether), fluoroalkylethylene, or chlorofluoroethylene.
The PTFE (B) is a melt-flowable PTFE (that is, the melt flow rate can be measured by the method described in the Examples) directly
20 obtained by polymerization of TFE without depending on treatments such as thermal decomposition or radiolysis, and has an MFR of 1 g/10 min or greater, preferably 5 g/10 min or greater. If the MFR is less than 1 g/10 min, the moldability of the composition is reduced. The upper limit of the MFR is not particularly limited but is usually selected from a range of 1 ,000
25 g/10 min or less. PTFE (B) can be manufactured by conventional methods such as solvent polymerization, emulsion polymerization, and suspension polymerization of TFE. U.S. Patent Nos. 3,067,262 and 6,060,167, Japanese Kokoku Patent No. Sho 57[1982]-22043, and U.S. Patent No. 5,789,504, disclose such methods.
30 PTFE (C) is a PTFE with a low molecular weight obtained by radiolysis of a non-melt flowable PTFE of high molecular weight. Such non-melt flowable PTFE is often called "molding powder" or "fine powder." Since the melt flowablity increases with decreasing molecular weight of the PTFE, the extent of decrease of the molecular weight can be , , om MFR of the PTFE as a function of degree of irradiation. The PTFE (C) in the present invention has an MFR of 0.01 g/10 min or greater, and preferably 0.1 g/10 min or greater. If the MFR is less than 0.01 g/10 min, uniform dispersion of the PTFE in the composition is difficult. The upper limit of the MFR is not particularly limited but is preferably in the range of 1 ,000 g/10 min or less. The PTFE (C) can be manufactured by irradiation with gamma rays or an electron beam of the above-mentioned "molding powder" or "fine powder" at a temperature lower than the melting temperature under vacuum or in air or in an inert gas atmosphere until the radiation dose reaches 10 kGy-1 MGy. The reaction is disclosed in Japanese Kokoku Patent Nos. Sho 47[1972]- 19609, Sho 52[1977]-38870, and GB 1 ,406,238.
The size of the PTFE (B) and the PTFE (C) particles are not particularly limited, and a powder with an average particle diameter of 0.01-100 μm can be used. A uniform composition is more easily obtained if the average particle diameter is preferably 0.05-50 μm, and more preferably 0.05-25 μm.
The above-mentioned PFA (A), PTFE (B), and PTFE (C) of the composition of the present invention, are mixed in the weight ratio of A/(B + C) ranging from 80/20 to 30/70, and preferably ranging from 80/20 to 40/60, and more preferably ranging from 80/20 to 50/50. If the content of (B + C) is less than 20 wt%, the improvement of the permeation resistance is small, and if the content is more than 70 wt%, durability and mechanical strength of the composition decrease. The composition of the present invention in which the PTFE component is composed of (B) and (C) has a permeation resistance improved by 20% or more compared to the permeation of PFA itself. If the ratio (A + B ) to C is in the range of 99.99/0.01 to 90/10 as the weight ratio of the PTFE (C), a sufficient improvement effect is obtained. If the ratio is less than 0.01 wt%, significant improvement in permeation resistance is not observed. The mixture ratio of more than 10 wt% tends to decrease the durability of the composition. The (A + B)/C weight ratio is preferably 99.9/0.1 to 95/5, and more preferably 99/1 to 95/5. , mpoaβd of the above-mentioned PFA (A),
PTFE (B)1 and PTFE (C) of the present invention can be melt processed and has an MFR of 0.1-100 g/10 min. If the MFR is less than 0.1 g/10 min, melt processing is difficult. If it is more than 100 g/10 min, the durability of the composition is unsatisfactory. The MFR is preferably 0.5- 50 g/10 min. The MFR of the composition can be estimated using the following equation.
(1/MFR of the composition)1734 = (weight % of PFA (A)) (1/MFR of PFA (A))1734 + (weight % of PTFE (B)) (1/MFR of PTFE (B))1734 + (weight % of PTFE (C)) (1/MFR of PTFE (C))1/34.
However, since the MFR of the composition sometimes deviates slightly from the numerical value obtained using the above-mentioned relation equation because of thermal decomposition or coupling phenomenon of the polymers during mixing or such post-treatments as fluorination, the MFR of the PFA (A), the PTFE (B), and the PTFE (C) can be estimated by taking this variation into consideration so that the MFR of the final composition will be in the desired range.
In the manufacture of the composition of the present invention, if the PTFE is not well mixed, durability of articles made from the composition will be reduced. Therefore it is preferable to charge the PFA (A), the PTFE (B), and the PTFE (C) into a batch type or continuous kneader or coaxial extruder and to uniformly melt-knead the ingredients. The PFA and PTFE powders can also be mixed in advance by dry or wet blending before melt-kneading. By wet blending is meant the mixing of dispersions of the PFA and one or both of the PTFEs. These dispersions may be the dispersions obtained by aqueous dispersion polymerization of PFA and the PTFE made by polymerizing TFE to the desired low molecular weight, or the dispersions may be made from the polymer in powder form by dispersing the powder in preferably aqueous medium with a dispersing agent, such as a surfactant. After blending, the polymers are isolated from the dispersion medium.
Also, the mixture can be obtained by adding the PTFE (B) and PTFE (C) to a polymerization medium in a polymerization vessel in aα ro n β l & polymθrizatlon of TFE and PAVE to make PFA (A). Alternatively, the PTFE (C) can be mixed with a powder of core/shell construction, which is obtained by adding particles of the PFA (A) to a polymerization medium in advance and initiating polymerization of the PTFE (B).
In the present invention, the PFA and the PTFE are preferably fluorinated before or after melt-kneading by the method described in U.S. Patent No. 4,743,658 and thereby reduce unstable end groups, to reduce the elution of fluorine ions, or to the improve the ozone resistance of articles made from the composition.
According to the present invention, an improved resistance to chemical permeation can be obtained by mixing only a small amount of the higher cost PTFE (C) in addition to the PTFE (B), so that the cost penalty is minimized. Also, since the PTFE has excellent heat resistance, chemical resistance, and purity similarly to that of the PFA, the composition of the present invention is suitable for a melt fabrication of parts for transferring various chemical solutions used in manufacturing processes of products such as chemicals, semiconductors and liquid crystal polymers. Examples of articles made from the composition of the present invention include tubes, pipes, hoses, films, sheets, round bars, and square rods by extrusion; moldings, fittings, filter housings, valves, pumps, containers, wafer carriers, vessels, tanks, flow meters by injection molding; containers such as bottles by blow molding or rotation molding; lining of valves, pumps, pipes, joints, by transfer molding; lining of steel, such as steel containers, tanks, pipes, by rotation molding; and sheets, by compression molding.
EXAMPLES
In the Examples and Comparative Examples explained below, a copolymer of TFE and PEVE obtained by the method described in U.S. Patent No. 5,760,151 is used as the PFA for making the compositions.
Properties were measured by the following methods: PAVE content: A sample was melt compressed at 3500C and cooled with water, so that a film with a thickness of about 50 μm was obtained. From the infrared absorption spectrum (in nitrogen atmosphere) of the film, the 1 . . , ,. " ra Vf "Content was^' etermined according to the method described in U.S.
Patent No. 5,760,151.
Melt flow rate (MFR): Using a melt indexer (made by Toyo Seiki Co., Ltd.) equipped with corrosion-resistant cylinder, die, and piston according to ASTM D1238-95, a 5 g sample was filled in the cylinder held at 372±10C.
The sample was held for 5 min, and extruded through the die orifice under a load (piston and weight) of 5 kg. The extrusion rate of the melt (g/10 min) was measured and reported as the MFR.
Nitrogen gas permeability: A film with a thickness of 0.25-0.35 mm prepared by a compression molding at 3500C was used for measuring the permeability at a temperature of 230C by an S-69 type gas and water vapor permeability measurement device made by Shibata Kagaku Kikai
K. K.
Comparative Example 1 and Examples 1, 2, and 3.
Ingredients
PFA (A): isPFA powder having an MFR of 1.5 g/10 min, PEVE content of 6.1 wt%, nitrogen gas permeability of 1.13 x 10'10 cm3 (STP) ■ cm/cm2 -sec ■ cmHg; PTFE (B): is PTFE powder (Zonyl® MP1600N made by Du Pont Co.) with an MFR of 20 g/10 min manufactured by a direct polymerization; PTFE (C): is PTFE powder (trade name: TLP made by DuPont-Mitsui Fluorochemicals Co., Ltd.) with an MFR of 0.4 g/10 min manufactured by radiolysis of a non-melt flowable PTFE having a high molecular weight. The above ingredients were blended by melt-kneading them at
360°C and 30 RPM for 10 min using a Plastomill (RH60 type) made by Toyo Seiki Co., Ltd. In these Examples, the weight ratio of A/(B + C) was set to 50/50, and the weight ratio of (A + B)/C was set to 100/0, 98.5/1.5, 95/5, and 90/10. The properties of each composition are summarized in Table I. ιr " " ■■' iω " '" " Comparative Example 2
90 parts by weight of the PFA (A) used in Example 1 and 10 parts by weight of the PTFE (C) used in Example 1 were melt-kneaded similarly to Example 1, so that a composition was obtained. The properties of the 5 composition are summarized in Table I. It can be seen that the combination of PTFE (B) and PTFE (C) reduces permeability to a greater extent that either of the PTFEs when used alone. This synergism is such that most of the benefit is obtained with even a small amount of PTFE (C). Further addition of PTFE (C) provides smaller incremental improvement.
10 Table 1
Comparative Example 1 Example 2 Example 3 Comparative
Example 1 Example 2
Amount PFA (A) 50 50 50 50 90 mixed (part by weight)
PTFE (B) 50 48.5 45 40 0
FPFE (C) 0 1.5 5 10 10
Properties of MFR (g/10 4.8 40 3.4 2.8 1.4 composition min)
Nitrogen gas 0.55 x 10"10 0.40 x 10'10 0.42 x 10"10 0.38 x 1Q-10 0.83 x 10'10 permeability, cm3 (STP) - cm/cm2 -sec • cmHg
Comparative Example 3 and Example 4.
15 Using the PFA (A), the PTFE (B), and the PTFE (C) of Example 1 , the weight ratio of A/(B + C) was set to 40/60, and the weight ratio of (A + B)/C was set to 100/0 and 98.5/1.5. Compositions are obtained by melt- kneading similarly to Example 1. The properties of the compositions are summarized in Table II. As in Table 1 , there is a large synergistic effect of
20 a small amount of PTFE (C) with PTFE (B) on permeation. Table 2
Comparative Example 4 Example 3
Amount mixed PFA (A) 40 40 (part by weight) PTFE (B) 60 58.5 PTFE (C) 0 1.5
Properties of MFR (g/10 min) 5.8 5.2 composition Nitrogen gas permeability, 0.51 x 10'10 0.34 x 10"10 cm3 (STP) • cm/cm2 -sec • cmHg
Hydrochloric Acid Permeation Samples from commercial PFA with an MFR of 1.9 g/10 min and a nitrogen gas permeability of 1.08 * 10-10 cm3 (STP) ■ cm/cm2 "sec ■ cmHg and from the composition of Example 4, were prepared as disk- shaped sheets with a thickness of 1 mm and a diameter of 77 mm by melt compression molding at 3500C. Reference is made to Fig. 1 , where these sheets 2a, 2b were sandwiched between cylinder 4 made of PTFE and container 1a and 1b made of PTFE with an inner diameter of 64 mm shown in Figure 1 via O- ring 3 made of a fluorine rubber and fastened, 60 ml_ 35% hydrochloric acid was put into the central cylinder 4 (a volume of 120 ml_), and the cylinder part was heated to 700C by a heater. Air 5a, 5b was fed to the PTFE containers 1a and 1 b, and the hydrochloric acid gas permeating through the sheets was trapped by trap bins 6a and 6b containing 300 ml_ pure water was put. Every three days, the chloride concentration (ppm) in the pure water was measured by an ion chromatography, and the amount of hydrochloric acid permeation was calculated using the following equation.
Hydrochloric acid permeation (unit: μg ■ mm/cm2) = chloride concentration x 300 x 1/(3.22 x 3.14)
This test was continued for 30 days. The total amount of hydrochloric acid permeated is summarized in Table III. The superior resistance of the Composition of Example 4 to hydrochloric acid permeation is clear. Table 3
Sample Commercial Composition of
PFA Example 4
Nitrogen gas permeability, cm3 (STP) - 1.08 x 10"10 0.34 x 10"10 cm/cm2 -sec • cm Hg
Total amount of hydrochloric acid 3.13 * 103 0.90 x 103 permeated (30 days) (μg ■ mm/cm2)

Claims

What is claimed is:
1. A fluoropolymer composition for melt processing, comprising (A) a tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer, (B) a melt- flowable polytetrafluoroethylene directly obtained by polymerization of tetrafluόroethylene, and (C) a polytetrafluoroethylene with a low molecular weight obtained by radiolysis of a non-melt flowable polytetrafluoroethylene with a high molecular weight; the weight ratio of A/(B + C) ranges from 80/20 to 30/70; and the weight ratio of (A + B)/C ranges from 99.99/0.01 to 90/10.
2. The composition of claim 1 , wherein the melt flow rate ranges from 0.1 to 100 g/10 min.
3. The composition of claim 1 , wherein the nitrogen gas permeability is 0.7 x 10-10 cm3 (STP) ■ cm/cm2 sec " cmHg or less.
4. The composition of claim 1 , wherein the perfluoro(alkyl vinyl ether) content of the copolymer (A) ranges from 3 to 20 wt%.
5. The composition of claim 1 , wherein the melt flow rate of the copolymer (A) ranges from 0.01 to100 g/10 min.
6. The composition of claim 1 , wherein the melt flow rate of the polytetrafluoroethylene (B) is 1 g/10 min or greater.
7. The composition of claim 1 , wherein the melt flow rate of the polytetrafluoroethylene (C) is 0.01 g/10 min or greater.
8. The composition of claim 1 , wherein the weight ratio of A/(B + C) ranges from 80/20 to 40/60.
9. The composition of claim 8, wherein the weight ratio of A/(B + C) ranges from 80/20 to 50/50. "" " "1O." •"■•T όmpo r D ca ms , w erein t e weight ratio of A/(B + C) ranges from 99.9/0.1 to 95/5.
11. The composition of claim 1 , wherein the melt processing is 5 extrusion.
12. The composition of claim 1 , wherein the melt processing is injection molding.
10 13. The composition of claim 1 , wherein the melt processing is blow molding.
14. The composition of claim 1 , wherein the melt processing is transfer molding.
15
15. The composition of claim 1 , wherein the melt processing is rotation molding.
16. The composition of claim 1 , wherein the melt processing is 20 compression molding.
EP06837041A 2005-11-08 2006-11-07 Fluoropolymer composition for melt processing Withdrawn EP1948733A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008037682A1 (en) 2008-08-14 2010-04-08 Strackharn, Klaus, Dr.med. Use of equipotent doses of local anesthetics or derivatives thereof for the treatment of chronic pain

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090152776A1 (en) * 2007-12-12 2009-06-18 E. I. Du Pont De Nemours And Company Core/Shell Polymer and Fluoropolymer Blending Blown Film Process
US8192677B2 (en) * 2007-12-12 2012-06-05 E. I. Du Pont De Nemours And Company Core/shell polymer and fluoropolymer blending blow molding and blown film process
BRPI0920472B1 (en) * 2008-09-26 2019-09-17 Whitford Corporation FLUOROPOLYMER COMPOSITION UNDERSTANDING HIGH MOLECULAR WEIGHT POLITETRAFLUOROETHYLENE (HPTFE), LOW MOLECULAR WEIGHT POLITETRAFLUORETHYLENE (LPTFE) AND PROCEDURE-FOLDING SUBFOLD AUCULATED AFTER CELLULAR APOLLUS
CA2784076A1 (en) * 2009-12-18 2011-06-23 Whitford Corporation Blended fluoropolymer compositions having multiple melt processible fluoropolymers
CN104093756B (en) * 2012-02-08 2016-09-28 纳幕尔杜邦公司 Core/shell fluoropolymers
JP6337504B2 (en) * 2014-02-21 2018-06-06 株式会社リコー Image processing apparatus, moving body, robot, device control method and program
CN104558365B (en) * 2014-12-24 2016-10-05 上海三爱富新材料股份有限公司 The preparation method of Meltability polytetrafluorethyletubular
JP7335685B2 (en) * 2018-06-07 2023-08-30 三井・ケマーズ フロロプロダクツ株式会社 Hot-melt fluororesin composition and injection-molded article made from the same

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0706542B1 (en) * 1993-06-30 2009-04-15 Dupont-Mitsui Fluorochemicals Co., Ltd. Containers and tubing formed from a TETRAFLUOROETHYLENE/FLUOROALKOXY TRIFLUOROETHYLENE COPOLYMER COMPOSITION
JP2002167488A (en) * 2000-11-30 2002-06-11 Du Pont Mitsui Fluorochem Co Ltd Tetrafluoroethylene/perfluoro(alkylvinyl ether) copolymer-reformed composition
JP3818641B2 (en) * 2001-11-30 2006-09-06 トヨタ自動車株式会社 Vehicle runway determination device and vehicle control device
JP2004228847A (en) * 2003-01-22 2004-08-12 Hitachi Ltd On-vehicle camera device
JP2004297306A (en) * 2003-03-26 2004-10-21 Pasuko:Kk Video recorder for road and river, and reproducing apparatus of video data
JP4262566B2 (en) * 2003-10-16 2009-05-13 株式会社日立製作所 In-vehicle imaging device and camera
WO2005038402A1 (en) * 2003-10-21 2005-04-28 Waro Iwane Navigation device

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2007056350A1 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102008037682A1 (en) 2008-08-14 2010-04-08 Strackharn, Klaus, Dr.med. Use of equipotent doses of local anesthetics or derivatives thereof for the treatment of chronic pain

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