EP0296559A2
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EP
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Modified polytetrafluoroethylene fine powder and process for preparing the same
Assignee: Daikin Industries Ltd
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Filing: 1988-06-22
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Granted: —
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Expires: 2008-06-22
Abstract
Abstract Modified PTFE fine powder which comprises colloidal particles of a copolymer comprising repeating units derived from tetrafluoroethylene and 0.02 to 0.3 % by weight, preferably 0.03 to 0.2 % by weight of repeating units derived from at least one fluoroalkyl vinyl ether selected from compounds of the formula: X(CF₂) n OCF=CF₂ (I) wherein X is a hydrogen, fluorine or chlorine atom and n is an integer of 1 to 6, and C₃F₇(OCF₂CF₂CF₂) m [OCF(CF₃)CF₂]₁OCF=CF₂ (II) wherein m and l are each an integer of 0 to 4 provided that at least one of them is not zero, which has a number average particle size of 0.05 to 0.6 µm, wherein the copolymer has a specific melt viscosity of from 6 x 10¹⁰ to 30 x 10¹⁰ poise, preferably from 8.0 x 10¹⁰ to 25 x 10¹⁰ poise at 380°C and a standard specific gravity (SSG, hereinafter defined) of from 2.135 to 2.175, preferably from 2.140 to 2.160 and a paste extruded article of the polymer has a green elongation of at least 400 % is provided.
Inventors
- 👤 Tetsuo Shimizu
- 👤 Kazutaka Hosokawa
- 👤 Masuo Kokumai
- 👤 Makoto Ono
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 11:26
CPC Classifications
C; C08; C08F; C08F214/00; C08F214/18; C08F214/26; C08F214/262
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
156 words
Modified polytetrafluoroethylene fine powder which comprises colloidal particles of a copolymer comprising repeating units derived from tetrafluoroethylene and 0.02 to 0.3 % by weight of repeating units derived from at least one fluoroalkyl vinyl ether selected from the group consisting of compounds of the formula: X(CF₂) n OCF=CF₂ (I) wherein X is a hydrogen, fluorine or chlorine atom and n is an integer of 1 to 6, and C₃F₇(OCF₂CF₂CF₂) m [OCF(CF₃)CF₂]₁OCF=CF₂ (II) wherein m and l are each an integer of 0 to 4 provided that at least one of them is not zero, which has a number average particle size of 0.05 to 0.6 µm, wherein the copolymer has a specific melt viscosity of from 6 x 10¹⁰ to 30 x 10¹⁰ poise at 380°C and a standard specific gravity (SSG, hereinbefore defined) of from 2.135 to 2.175 and a paste extruded article of the polymer has a green elongation of at least 400 %.
Claim 2
Dependent Claim
156 words
Modified polytetrafluoroethylene fine powder which comprises colloidal particles of a copolymer comprising repeating units derived from tetrafluoroethylene and 0.02 to 0.3 % by weight of repeating units derived from at least one fluoroalkyl vinyl ether selected from the group consisting of compounds of the formula: X(CF₂) n OCF=CF₂ (I) wherein X is a hydrogen, fluorine or chlorine atom and n is an integer of 1 to 6, and C₃F₇(OCF₂CF₂CF₂) m [OCF(CF₃)CF₂]₁OCF=CF₂ (II) wherein m and l are each an integer of 0 to 4 provided that at least one of them is not zero, which has a number average particle size of 0.05 to 0.6 µm, wherein the copolymer has a specific melt viscosity of from 6 x 10¹⁰ to 30 x 10¹⁰ poise at 380°C and a standard specific gravity (SSG, hereinbefore defined) of from 2.135 to 2.175 and a paste extruded article of the polymer has a green elongation of at least 400 %.
Claim 3
Dependent Claim
25 words
The modified polytetrafluoroethylene fine powder according to claim 1, wherein the content of the fluoroalkyl vinyl ether is from 0.03 to 0.2 % by weight.
Claim 4
Dependent Claim
26 words
The modified polytetrafluoroethylene fine powder according to claim 1, wherein the specific melt viscosity is from 8.0 x 10¹⁰ to 25 x 10¹⁰ poise at 380°C.
Claim 5
Dependent Claim
19 words
The modified polytetrafluoroethylene fine powder according to claim 1, wherein the standard specific gravity is from 2.140 to 2.170.
Claim 6
Dependent Claim
19 words
The modified polytetrafluoroethylene fine powder according to claim 4, wherein the standard specific gravity is from 2.140 to 2.160.
Claim 7
Dependent Claim
18 words
The modified polytetrafluoroethylene fine powder according to claim 1, wherein the fluoroalkyl vinyl ether is C₃F₇OCF=CF₂ or C₄F₉OCF=CF₂.
Claim 8
Dependent Claim
16 words
The modified polytetrafluoroethylene fine powder according to claim 1, wherein the fluoroalkyl vinyl ether is ClC₃F₆OCF=CF₂.
Claim 9
Dependent Claim
27 words
The modified polytetrafluoroethylene fine powder according to claim 1, wherein the fluoroalkyl vinyl ether is a compound of the formula: C₃F₇[OCF(CF₃)CF₂]₁OCF=CF₂ wherein l is 1 or 2.
Claim 10
Dependent Claim
184 words
A process for preparing polytetrafluoroethylene fine powder of claim 1, which comprises copolymerizing tetrafluoroethylene and at least one fluoroalkyl vinyl ether selected from the group consisting of the compounds of the formulae: X(CF₂) n OCF=CF₂ (I) wherein X is a hydrogen, fluorine or chlorine atom and n is an integer of 1 to 6, and C₃F₇(OCF₂CF₂CF₂) m (OCF(CF₃)CF₂]₁OCF=CF₂ (II) wherein m and l are each an integer of 0 to 4 provided that at least one of them is not zero in an aqueous medium containing 0.03 to 0.3 % by weight of a water-soluble fluorine-containing dispersant under reaction pressure of from 6 to 40 kg/cm²G at a temperature of from 10 to 95°C in the presence of a polymerization initiator wherein, after the copolymerization is initiated and at least 10 % by weight of the finally produced copolymer is copolymerized and before at most 85 % by weight of the finally produced copolymer is copolymerized, (a) a radical scavenger in an amount of 0.2 to 5 times mole of the polymerization initiator or (b) the polymerization temperature is lowered by 10 to 40°C.
Claim 11
Dependent Claim
50 words
The process according to claim 9, wherein the addition of the radical scavenger or decrease of the reaction temperature is effected after at least 30 % by weight of the finally produced copolymer is copolymerized and before at most 70 % by weight of the finally produced copolymer is copolymerized.
Claim 12
Dependent Claim
38 words
The process according to claim 9, wherein, as the polymerization initiator, 2 to 30 ppm of ammonium persulfate or alkali metal persulfate is used, and the reaction pressure is kept in a range from 6 ot 17 kg/cm²G.
Claim 13
Dependent Claim
44 words
The process according to claim 9, wherein, as the polymerization initiator, 20 to 1,000 ppm of disuccinic acid peroxide and a 1/50 to 1/50 time amount of ammonium persulfate are used in combination, and the reaction condition is changed by lowering the reaction temperature.
Claim 14
Dependent Claim
92 words
The process according to claim 9, wherein as the water soluble fluorine-containing dispersant, C n F 2n+1 COOM or C₃F₇O[CF(CF₃)CF₂O] p CF(CF₃)COOM wherein n is an integer of 6 to 9, p is 1 or 2 and M is an ammonium group or an alkali metal is used in a concentration of 0.05 to 0.2 % by weight, as the polymerization initiator, ammonium persulfate or alkali metal persulfate is used in a concentration of 5 to 20 ppm, and the reaction temperature is kept in a range from about 60 to 90°C.
Claim 15
Dependent Claim
47 words
The process according to claim 9, wherein, as the polymerization initiator, disuccinic acid peroxide in a concentration of 40 to 300 ppm and 1/50 to 1/8 time of the disuccinic acid peroxide of ammonium persulfate in a concentration of 3 to 10 ppm are used in combination.
Claim 16
Dependent Claim
42 words
The process according to claim 9, wherein the radical scavenger is at least one selected from the group consisting of aromatic hydroxy compounds, aromatic amine compounds and quinones which have solubility in water of at least 2.5 x 10⁻⁶ mole/l at 25°C.
Claim 17
Dependent Claim
12 words
The process according to claim 15, wherein the radical scavenger is hydroquinone.
Claim 18
Dependent Claim
14 words
The process according to claim 9, the fluoroalkyl vinyl ether is C₃F₇OCF=CF₂ or C₄F₉OCF=CF₂.
Claim 19
Dependent Claim
13 words
The process according to claim 9, wherein the fluoroalkyl vinyl ether is ClC₃F₆OCF=CF₂.
Claim 20
Dependent Claim
24 words
The process according to claim 9, wherein the fluoroalkyl vinyl ether is a compound of the formula: C₃F₇[OCF(CF₃)CF₂]₁OCF=CF₂ wherein l is 1 or 2.
References Cited (Backward Citations)
No citation records indexed.
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