CN101113189A - Method for preparing modified polytetrafluoroethylene - Google Patents
Method for preparing modified polytetrafluoroethylene Download PDFInfo
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- CN101113189A CN101113189A CN 200710014845 CN200710014845A CN101113189A CN 101113189 A CN101113189 A CN 101113189A CN 200710014845 CN200710014845 CN 200710014845 CN 200710014845 A CN200710014845 A CN 200710014845A CN 101113189 A CN101113189 A CN 101113189A
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- tetrafluoroethylene
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Abstract
The invention relates to a preparation method of tetrafluoroethylene and pertains to the polymer chemistry field. In the water medium of a water-soluble initiation system, under the pressure of 0.3-3Mpa and modifier, the tetrafluoroethylene is prepared and the reaction temperature is 0-80 DEG C. The resin obtained by the method of the invention has excellent processability and is better than ordinary PTFE resin.
Description
Technical field
The invention belongs to field of polymer technology, relate to a kind of polymerization process of tetrafluoroethylene, relate in particular to method by the suspension polymerization modified Teflon.
Background technology
The method of modified poly can be used for synthetic various polymkeric substance, to improve polymer properties.The uniform distribution of general requirement properties-correcting agent is so that obtain the highest product performance.
For the tetrafluoroethylene (PTFE) for preparing modification, usually use a spot of comonomer, this comonomer comprises R 1216 (HFP), the close ether of perfluoro-methyl vinyl (PMVE), the close ether of perfluoro propyl vinyl (PPVE), trifluorochloroethylene (CTFE) perfluorobutyl ethylene or non-fluorine-containing unsaturated hydrocarbons.The molar content of this properties-correcting agent is generally less than 1% for being no more than 2% in the modified ptfe that obtains.
Typical suspension polymerization known in the art comprises the following steps: a kind of liquid medium is pre-loaded in the vertical response still of band stirring, chuck, be pre-loaded into other modifier components of comprising initiator on a small quantity, deoxidation, with nitrogen replacement, be pressurized to predeterminated level, stir, make system to reach temperature required with TFE, add more TFE and properties-correcting agent attemperation according to predetermined benchmark.The process that adds initiator with identical or different speed can continue until the part of whole batch of material or lasting batch of material or only adds before reaction, the process of TFE suspension polymerization is generally carried out in water or CO 2 medium, substantially do not participate in polyreaction, cheap and safety, in whole polymerization process, maintain certain level, select the non-constant operating parameters of equipment usually.
Chinese patent application CN1147262 discloses a kind of method of suspension polymerization of tetrafluoroethylene, it is characterized in that beginning polymerization and be warming up to comparatively high temps in reaction process at low temperature.
Chinese patent application CN1163281 discloses a kind of non-free flowable molding powders of modified polytetrafluoroethylenes.The unitary tetrafluoroethylene suspension polymer of at least a perfluoroalkyl vinyl ether that will contain 0.01～1% weight is ground to particle diameter to be 10～50 μ m and to assemble in water, and obtaining tap density is the non-particulate shape of 450/l, the molding powder machine that does not play dirt.
Chinese patent application CN1058219 discloses the method for making tetrafluoro ethylene polymer in a kind of aqeous suspension, before polymerization begins, pressurize in the tetrafluoroethylene suspension polymerization process and send into tetrafluoroethylene and indifferent gas mixture, these mixture stagnation pressure 5～50 crust, corresponding additional tetrafluoroethylene is to remain on said concentration in this scope in tetrafluoroethylene concentration 30～70mol% polymerization process, and the characteristics of the granular PTFE powder of gained are that grain pattern and abrasive property are improved.
Chinese patent application CN1714109 discloses a kind of granular tetrafluoroethylene of lower molecular weight of direct polymerization, and described being aggregated in the water medium carried out in the presence of radical initiator and telogen.Described reaction vessel fully stirs between polymerization period, so that tetrafluoroethylene or modified Teflon are condensed.Melt viscosity is about 1 * 10
6Granular tetrafluoroethylene of lower molecular weight or modified Teflon powder that Pas is following are directly emanated out from reaction vessel.Has melt viscosity about 1 * 10 according to low molecular weight polytetrafluoroethylene of the present invention or modified Teflon powder
6Below the Pas, the about 8m of specific surface area
2Below/the g, can extract the about 3ppm of content of fluoride or lower (by weight), and be about 5 or lower indicated narrow molecular weight distributions by polydispersity index.The lower molecular weight powder particle has about 2～about 40 microns of average particle size, and described powder does not contain granularity substantially less than about 1 micron particle.So the low molecular weight material of producing is suitable for use as the additive such as other materials such as printing ink, coating, lubricating grease, lubricant and plastics.
Chinese patent application CN1774457 discloses a kind of melt-processable tetrafluoroethylene/fluorinated vinyl ether copolymer by suspension polymerization, the multipolymer of a kind of melt-processable, toughness tetrafluoroethylene and fluorinated vinyl ether is pressed suspension polymerization production, comprise: tetrafluoroethylene and fluorinated vinyl ether carry out copolymerization in the reaction vessel of the pressurization that water medium, radical initiator and telogen are housed, stirring, this water medium is substantially free of fluorine-containing organic solvent.During the polyreaction material in the described reaction vessel is fully stirred so that the multipolymer of tetrafluoroethylene and fluorinated vinyl ether is condensed.With melt viscosity less than about 1 * 10
6This melt-processable of Pa.s, toughness copolymer are directly separated from reaction vessel.
Above-mentioned patent application CN1147262 and patent application CN1058219, the single polymers that obtains, the polymkeric substance particle diameter that patent application CN1163281 and patent application CN1714109 obtain is less, molecular weight is lower, patent application CN1774457 obtains the polymkeric substance of melt-processable, the application facet high to performance requriements can't satisfy, and the product big for dimensional requirement also can't satisfy.
Summary of the invention
The present invention is directed to the deficiencies in the prior art, a kind of polymerization process of tetrafluoroethylene is provided.
The invention provides a kind of polymerization process of tetrafluoroethylene, be included in the water medium of water soluble initiator, under the 0.3-3Mpa pressure, prepare tetrafluoroethylene in the presence of properties-correcting agent, temperature of reaction is 0-80 ℃.
Preferably, described properties-correcting agent is undersaturated hydro carbons, and undersaturated hydro carbons is selected from perfluoroolefine, non-Fluorine containing olefine; Perfluoroolefine is selected from R 1216 (HFP) or perfluoroalkyl vinyl ether, and non-Fluorine containing olefine comprises unsaturated alkane such as ethene, propylene.Perfluoroalkyl vinyl ether is selected from the close ether of perfluoro-methyl vinyl (PMVE), the close ether of perfluoro propyl vinyl (PPVE) or trifluorochloroethylene (CTFE).The molar content of properties-correcting agent is 0.01～2% of a tetrafluoroethylene, preferred 1-0.01%, more preferably 0.5-0.1%.
Preferably, water soluble initiator is selected from persulfuric acid salt initiator system or redox initiation system.The Sulfates initiator system is selected from ammonium persulphate or the inferior salt of sulfuric acid.Initiator concentration is the 0.1-2% of polymkeric substance, volume percent.
Preferably, pressure is 0.5～2.0Mpa, preferred 0.5～1.2Mpa.
The invention has the advantages that TFE is aggregated under certain pressure, the temperature condition begins, and the polymerization later stage reaches higher temperature, and finishes polymerization under hot conditions.The pressure of TFE carries out in comparison constant pressure 0.2～2.0Mpa scope.The critical temperature of TFE is 33 ℃.Carry out being lower than under this temperature, pressure must keep certain level, in order to avoid TFE carries out in liquid phase.
The amount of polymerization reactor medium of packing in the present invention is 40～80% of a reaction vessel volume, the best is 50～70%, the volume that can make full use of reactor can make polymkeric substance possess certain space again, and reaction heat energy safety is removed, and makes full use of reactor volume and improves reaction efficiency.
Pressure can suitably be adjusted in the method for the invention, high pressure is more excellent aspect the raising speed of response, the polymerization of TFE is heat release, high reaction rate depends on the control of reaction heat, and polymeric pressure depends on the design of equipment and the consideration of TFE polymerization safety, general suspension polymerization for TFE, the known pressure scope is 0.3～3Mpa, be generally 0.4～1.8Mpa, maintenance constant reaction pressure is beneficial to the control of reaction, but pressure also can change.
The initiator that uses in practice of the present invention is included in the TFE polymerization process, all effective radical initiator.This initiator can decompose free radical by given pace in reaction system.Be suitable for the inferior salt of TFE polymeric initiator system such as persulphate/sulfuric acid, persulphate/ferrous sulfate/sulfuric acid, and inorganic peroxide initiator.
Initiator concentration influences the speed of polyreaction in the present invention, polymer performance, and initiator amount is for obtaining the amount of enough PTFE.Set forth as the tetrafluoroethylene field, it depends on the efficient of initiator.Initiator amount is a benchmark for reaching polymer weight.
The stirring velocity of polymeric kettle among the present invention is fast TFE (with other comonomer that exists) to be distributed to aqueous phase, and the heat of polymerization of reaction is in time conducted, and polymerization velocity depends on good stirring efficiency in the presence of enough promoting agent initiators.
Method of the present invention can be used for preparing the PTFE resin of various particle diameter powder, and described resin has the character of improvement, and the polymkeric substance that is obtained is through smashing to pieces, washing, and drying can obtain the middle granularity and the fine powder of required particle diameter after the pulverizing.
Method of the present invention can be used for preparing the polytetrafluoroethyl-ne alkene copolymer, and prepared multipolymer has specific physical and mechanical property ideal and is used for for example inwall etc. of electric wire, cable, container of electrochemical applications field.Method of the present invention obtains resin and has superior processing characteristics, is better than common PTFE resin.
Embodiment
If no special instructions, the medium that the inventive method is used is at water known in the art, uses the equipment of TFE suspension polymerization well known in the art and technology to carry out.
The standard specific gravity of resin properties: PTFE (SSG) is measured by the method for ASTMD-4895.
Multipolymer is formed: use disclosed method in the United States Patent (USP) 4,837,267, measure the co-monomer content of modified ptfe resin by Fourier transform infrared spectroscopy.
The contrast fluoropolymer is according to US5,106,911; US5, the method that discloses in 710,217 preparation.
By the following examples the present invention is further detailed, but the present invention is not limited thereto.If no special instructions, the amount among the embodiment " part " all is parts by volume.
Embodiment 1
In a polymeric kettle with propeller agitator and 20L, 13 parts of (parts by volume, the as follows) soft water of packing into add 0.038 part of ammonium persulphate, and 0.0038 part of ferrous sulfate adds 0.5 part of PPVE.Build kettle cover, find time in the still still temperature drop to 20 ℃, the qualified back of substitutability analysis oxygen level adds TFE to 1.0Mpa, stirring velocity is constant, reaction for some time afterreaction speed can decrease, and stopped reaction when treating that TFE consumes 4200g is pulverized the dry back of washing with the polymkeric substance of reaction and obtained 4KgPTFE, through the molar content through infrared spectra detection PPVE is 0.5%, and the polymer performance index of acquisition is superior.Film after the turning can weld, and is transparent, has superior processing characteristics.
Embodiment 2
The 12.5 parts of soft water of in a polymeric kettle with propeller agitator and 20L, packing into, add 0.032 part of initiator, add 0.0032 part of ferrous sulfate, add 0.5 part of PPVE, build kettle cover, find time in the still, with still be cooled to 20 ℃ of substitutability analysis oxygen levels qualified after, add TFE to 1.2Mpa, stirring velocity is constant, stopped reaction when question response speed reduction TFE consumes 4200g is pulverized the polymkeric substance that obtains, the dry back acquisition of washing 4KgPTFE, through the infrared spectra check and analysis, the molar content of PPVE is 0.52%, and the PTFE performance index of acquisition are superior, have extremely excellent processing characteristics.
Embodiment 3
In a polymeric kettle with propeller agitator and 20L, the 13 parts of soft water of packing into, add 0.038 part of ammonium persulphate, add 0.0038 part of ferrous sulfate, add 0.25 part of PPVE and build kettle cover, find time in the still still temperature drop to 20 ℃, the qualified back of substitutability analysis oxygen level adds TFE to 0.8Mpa, stirring velocity is constant, stopped reaction when question response speed reduction TFE consumes 4200g is pulverized the dry back acquisition of washing 4KgPTFE with the polymkeric substance that reacts, and the molar content of process infrared spectra check and analysis PPVE is 0.26%, the PTFE performance index that obtain are superior, have extremely excellent processing characteristics
Embodiment 4
In a polymeric kettle with propeller agitator and 20L, the 13 parts of soft water of packing into, add 0.038 part of ammonium persulphate, add 0.0038 part of ferrous sulfate, add 0.25 part of PPVE and build kettle cover, find time in the still still temperature drop to 20 ℃, the qualified back of substitutability analysis oxygen level adds TFE to 1.2Mpa, stirring velocity is constant, and stopped reaction when question response speed reduction TFE consumes 4200g is pulverized the dry back acquisition of washing 4KgPTFE with the polymkeric substance of reaction, molar content through infrared spectra check and analysis PPVE is 0.23%, the transformation efficiency of PPVE is 84%, and the PTFE performance index of acquisition are superior, have extremely excellent processing characteristics.
Embodiment 5
In a polymeric kettle with propeller agitator and 20L, the 13 parts of soft water of packing into, add 0.023 part of initiator, add 0.5 part of PPVE, build kettle cover, find time in the still, the qualified back of substitutability analysis oxygen level adds TFE to 0.1Mpa, and stirring velocity is constant, with temperature rise to 70 in the reactor ℃, add TFE to 0.8Mpa, stopped reaction when question response speed reduction TFE consumes 4200g is pulverized the dry back acquisition of washing 3.98KgPTFE with the polymkeric substance that reacts, and the molar content of process infrared spectra check and analysis PPVE is 0.35%, the PTFE performance index that obtain are superior, have extremely excellent processing characteristics.
Embodiment 6
In a polymeric kettle with propeller agitator and 20L, the 12.5 parts of soft water of packing into, add 0.023 part of ammonium persulphate, add 0.5 part of CTFE, build kettle cover, find time in the still, the qualified back of substitutability analysis oxygen level adds TFE to 0.1Mpa, and stirring velocity is 500 rev/mins, with temperature rise to 65 in the reactor ℃, add TFE to 1.0Mpa, stopped reaction when question response speed reduction TFE consumes 4200g is pulverized the dry back acquisition of washing 4KgPTFE with the polymkeric substance of reaction, molar content through infrared spectra check and analysis PPVE is 0.4%, the transformation efficiency of PPVE is 71%, and the PTFE performance index of acquisition are superior, have extremely excellent processing characteristics.
Embodiment 7
In a polymeric kettle with propeller agitator and 20L, the 12.5 parts of soft water of packing into, add 0.023 part of ammonium persulphate, add 0.14 part of PMVE, build kettle cover, find time in the still, the qualified back of substitutability analysis oxygen level adds TFE to 0.1Mpa, and stirring velocity is constant, with temperature rise to 70 in the reactor ℃, add TFE to 1.2Mpa, stopped reaction when question response speed reduction TFE consumes 4200g is pulverized the dry back acquisition of washing 4KgPTFE with the polymkeric substance that reacts, and the molar content of process infrared spectra check and analysis PPVE is 0.1%, the PTFE performance index that obtain are superior, have extremely excellent processing characteristics.
Embodiment 8
In a polymeric kettle with propeller agitator and 20L, the 13 parts of soft water of packing into, add 0.038 part of ammonium persulphate, add 0.0038 part of ferrous sulfate, add 0.9 part of HFP, build kettle cover, find time in the still, after the substitutability analysis oxygen level is qualified, with still temperature drop to 20 ℃, stirring velocity is constant, adds TFE to 1.0Mpa, stopped reaction when question response speed reduction TFE consumes 4.2Kg, the polymkeric substance of reaction is pulverized the dry back of washing obtain 3.9KgPTFE, molar content through infrared spectra check and analysis PPVE is 0.1%, and the PTFE performance index of acquisition are superior, have extremely excellent processing characteristics.
Claims (7)
1. the polymerization process of a tetrafluoroethylene is included in the water medium of water soluble initiator, prepares tetrafluoroethylene under 0.3-3Mpa pressure, in the presence of properties-correcting agent, and temperature of reaction is 0-80 ℃.
2. the polymerization process of tetrafluoroethylene as claimed in claim 1, it is characterized in that, described properties-correcting agent is selected from R 1216 (HFP), the close ether of perfluoro-methyl vinyl (PMVE), the close ether of perfluoro propyl vinyl (PPVE) or trifluorochloroethylene (CTFE), the molar content of properties-correcting agent is 0.01～2% of a tetrafluoroethylene, preferred 1-0.01%, more preferably 0.5-0.1%.
3. the polymerization process of tetrafluoroethylene as claimed in claim 1 is characterized in that, water soluble initiator is selected from persulfuric acid salt initiator system or redox initiation system.
4. the polymerization process of tetrafluoroethylene as claimed in claim 3 is characterized in that, the Sulfates initiator system is selected from ammonium persulphate or the inferior salt of sulfuric acid.
5. the polymerization process of tetrafluoroethylene as claimed in claim 1 is characterized in that, initiator concentration is the 0.1-2% volume percent of polymkeric substance.
6. the polymerization process of tetrafluoroethylene as claimed in claim 1 is characterized in that, pressure is 0.5～2.0Mpa.
7. the polymerization process of tetrafluoroethylene as claimed in claim 1 is characterized in that, pressure is 0.5～1.2Mpa.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200710014845 CN101113189A (en) | 2007-08-24 | 2007-08-24 | Method for preparing modified polytetrafluoroethylene |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 200710014845 CN101113189A (en) | 2007-08-24 | 2007-08-24 | Method for preparing modified polytetrafluoroethylene |
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| CN101113189A true CN101113189A (en) | 2008-01-30 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102977250A (en) * | 2012-12-30 | 2013-03-20 | 南京肯特复合材料有限公司 | Modified polytetrafluoroethylene, preparation method of modified polytetrafluoroethylene and application of modified polytetrafluoroethylene to high frequency connector |
| CN105315395A (en) * | 2015-10-22 | 2016-02-10 | 浙江巨圣氟化学有限公司 | Preparation method of high-performance suspension PTFE |
| CN109721670A (en) * | 2018-11-12 | 2019-05-07 | 江苏梅兰化工有限公司 | A kind of preparation method of narrow partial size suspension injecting tetrafluoroethylene PTFE resin |
| CN114276213A (en) * | 2021-12-30 | 2022-04-05 | 浙江博瑞电子科技有限公司 | Method for removing trace unsaturated impurities of fluorine-containing organic matter |
-
2007
- 2007-08-24 CN CN 200710014845 patent/CN101113189A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102977250A (en) * | 2012-12-30 | 2013-03-20 | 南京肯特复合材料有限公司 | Modified polytetrafluoroethylene, preparation method of modified polytetrafluoroethylene and application of modified polytetrafluoroethylene to high frequency connector |
| CN102977250B (en) * | 2012-12-30 | 2016-03-30 | 南京肯特复合材料有限公司 | Modified Teflon, manufacture method and the application on high frequency connectors thereof |
| CN105315395A (en) * | 2015-10-22 | 2016-02-10 | 浙江巨圣氟化学有限公司 | Preparation method of high-performance suspension PTFE |
| CN109721670A (en) * | 2018-11-12 | 2019-05-07 | 江苏梅兰化工有限公司 | A kind of preparation method of narrow partial size suspension injecting tetrafluoroethylene PTFE resin |
| CN114276213A (en) * | 2021-12-30 | 2022-04-05 | 浙江博瑞电子科技有限公司 | Method for removing trace unsaturated impurities of fluorine-containing organic matter |
| CN114276213B (en) * | 2021-12-30 | 2024-03-19 | 浙江博瑞电子科技有限公司 | Method for removing trace unsaturated impurities of fluorine-containing organic matters |
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Open date: 20080130 |