Polyether diacitates or their salt-based surfactants and their use
Polyether diacitates or salt-based surfactants address the environmental concerns of PFOA by reducing surface tension and improving dispersion stability in fluorine-containing polymers, enabling lower surfactant usage and safer production methods.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- ZHONGHAO CHENGUANG RES INST OF CHEMICALINDUSTRY CO LTD
- Filing Date
- 2021-09-28
- Publication Date
- 2026-04-13
Abstract
Description
cross reference
[0001] This application claims priority based on Chinese Patent Application No. 202110653981.X, filed on June 11, 2021, with the title of the invention "Polyether Dio Acid or Salt-Based Surfactant and Use thereof," and incorporates its entire contents by reference. [Technical Field]
[0002] The present invention relates to the technical field of fluorine-containing polymers, and more particularly to polyether diacitates or their salt-based surfactants and their use. [Background technology]
[0003] Among the many types of surfactants, fluorine-containing surfactants exhibit superior performance. Perfluorooctanoic acid (PFOA) and its salts (e.g., ammonium salts and sodium salts) are the most widely used types of fluorine-containing surfactants, and their primary application is as an additive in the manufacture of fluorine-containing functional polymer materials. In recent years, as PFOA has become more widely used, its potential impact on the environment and health has gradually become apparent, leading to increasingly strict restrictions on its production and use.
[0004] From a molecular structure perspective, fluorine-containing surfactants that replace PFOA need to possess not only excellent surface properties that meet the requirements of water repellency, oil repellency, and high surfactant activity, but also properties such as low toxicity and easy decomposition that meet the requirements of environmental protection and health. Currently, the technological routes for developing PFOA substitutes both domestically and internationally are mainly divided into two types: those that develop fluorinated carbon-based surfactants containing short chains or branched chains, and those that introduce ether bonds and methylene groups or similar groups into fluorinated carbon chains.
[0005] In CN101535352A, a fluorine-containing polyetheric acid or a salt thereof with a number-average molecular mass of at least 800 g / mol is used as the main emulsifier, and [R1-O n -LA-] - Y+ Structure (wherein R1 is a linear or branched partially or fully fluorinated aliphatic group which may contain an ether linkage, n is 0 or 1, L is a non-fluorinated, partially or fully fluorinated linear or branched alkylene group which may contain an ether linkage, A- is an anion such as a carboxylate group, sulfonate group, sulfonamide group or phosphonate group, Y + is hydrogen, ammonium, or alkali metal cation, and R1-O n By using a compound having a -L- chain length of 6 atoms or less or a siloxane surfactant as an auxiliary emulsifier, a high-performance aqueous dispersion of a fluorine-containing polymer is produced, and the amount of fluorine-containing emulsifier used is less than 0.03% (parts by mass) of the amount of aqueous dispersion used.
[0006] CN101223228A discloses the production of an aqueous dispersion of a fluorine-containing polymer using a nonionic, non-fluorinated emulsifier, wherein the emulsifier used comprises polyethylene glycol and / or polypropylene glycol segments having 3 to 100 repeating units, and in terms of structure, each end may contain the same or different terminal groups, such as hydroxyl groups, carboxylic acid esters, benzoic acid esters, acrylates, methacrylates, ethers, hydrocarbons, phenols, functionalized phenols, esters, fatty acid esters, etc.
[0007] This invention was made in view of the above. [Overview of the project]
[0008] The present invention provides polyether diacitates or salt-based surfactants that are safe to use, environmentally friendly, easily biodegradable, and can replace the use of some fluorine-containing surfactants in fluorine-containing polymers. Another aspect of the present invention provides the use of said polyether diacitates or salt-based surfactants.
[0009] Specifically, the present invention provides the following technical solutions.
[0010] The present invention relates to a general structural formula: X-L-(O-CH2CHZ) a -(O-CR 1 R 2 CR 3 R 4 ) b -O-L-X (wherein, Z represents H or CH3, L represents an alkylene group having 1 to 5 carbon atoms, X represents -COOM or -SO3M, M represents H + , NH 4+ or Na + , R1 to R4 each independently represent a hydrogen atom, a fluorine atom, a non-fluorinated alkyl group or alkoxy group, a partially fluorinated alkyl group or alkoxy group, or a fully fluorinated alkyl group or alkoxy group, and a and b each independently represent a positive integer of 0 to 10.) To provide a polyether diacid or a salt-based surfactant represented by the following formula:
[0011] In the present invention, it has been unexpectedly discovered that the above polyether diacid or its salt-based surfactant can significantly reduce the surface tension of the polymerization system, improve the stability of the aqueous dispersion of the fluorine-containing polymer, and significantly reduce the amount of the fluorine-containing surfactant used.
[0012] In the present invention, the polyether segment of the polyether diacid or its salt-based surfactant has an arbitrary chain structure in which oxygen atoms in the molecular main chain are separated by saturated hydrocarbon groups having two carbon atoms. In the structural formula of the polyether diacid or its salt-based surfactant, one or more fluorinated hydrocarbon groups may be present. Representative structures have the following repeating units. -CH2-CH2-O- (2) -CH2-CF2-O- (3) -CF2-CF2-O- (4) -CH2-CCH3-O- (5) -CF2-CCF3-O- (6) -CH2-CH(OCH3)-O- (7) -CH2-CH(CH2OH)-O- (8);
[0013] The polyether diacid or salt-based surfactant provided in the present invention has two terminal groups X which are carboxylate groups or sulfonate groups, the carboxylate groups and sulfonate groups may exist in the form of an acid or a salt thereof, and has at least two ether bonds, preferably at least four ether bonds, and more preferably at least six ether bonds.
[0014] In a preferred embodiment, Z represents H, L represents the alkylene group of C2, X represents -COOM, and M represents NH4. + Represents R 1 ~R 4 Each of the symbols independently represents a hydrogen atom, and a and b independently represent positive integers from 1 to 5.
[0015] Furthermore, the polyether diacitic acid or its salt-based surfactant is one or two selected from the following structural formulas. NH 4 OOC-CH2CH2-(O-CH2CH2)3-O-CH2CH2-COONH 4 NH 4 OOC-CH2CH2-(O-CH2CH2)5-O-CH2CH2-COONH 4
[0016] The present invention also provides the use of the polyether diacitate or its salt-based surfactant in the production of a fluorine-containing polymer, preferably in the production of an aqueous dispersion of the fluorine-containing polymer.
[0017] The present invention also provides a dispersant comprising the aforementioned polyether diacitate or its salt-based surfactant, and a fluorine-containing surfactant.
[0018] Using the polyether diacitate or its salt-based surfactant provided in the present invention as a dispersant makes it easy to separate the fluorine-containing polymer from the aqueous dispersion.
[0019] In a preferred embodiment, the fluorine-containing surfactant has a general structural formula: R f -O-CZ1Z2CZ3Z4-X (In the formula, R f The first part represents a perfluoroalkyl group or alkoxy group of C1 to C5, the second part represents a hydrogen atom or a fluorine atom, the third part represents -COOM or -SO3M, and the fourth part represents H + NH4 + or Na + (This represents...) It is represented by [this].
[0020] In the present invention, the fluorine-containing surfactant is particularly suitable for use in combination with the polyether diacitate or its salt-based surfactant according to the present invention.
[0021] Furthermore, the fluorine-containing surfactant is one or more selected from the following structural formulas. CF3-O-CF(CF3)CF2-O-CH2CH2COOM CF3OCF2OCF2CF2-O-CH2CH2COOM CF3-OCF(CF3)CF2-O-CH2CH2SO3M CF3OCF2OCF2CF2-O-CH2CH2SO3M (In the formula, M is H + or NH4 + (This represents...)
[0022] Furthermore, the fluorine-containing surfactant has the general structural formula: CF3-OCF(CF3)-CF2-O-CH2CH2COONH4 It is represented by [this].
[0023] In a preferred embodiment, the amount of the fluorine-containing surfactant used is 5 to 50%, and preferably 10 to 30%, based on the total mass of the dispersant.
[0024] In the present invention, when the mass ratio of polyether diacitor or a salt-based surfactant and a fluorine-containing surfactant is within the above range, the surface tension when a mixture of the two is dissolved in water to a concentration of 2000 ppm is at least 20% lower than the surface tension when the same concentration of fluorine-containing surfactant is used alone.
[0025] The present invention also provides a method for producing an aqueous dispersion of a fluorine-containing polymer, comprising polymerizing at least one fluorine-containing monomer in an aqueous dispersion system using the above-mentioned dispersant as a dispersant.
[0026] In a preferred embodiment, the fluorine-containing monomer is one or more selected from tetrafluoroethylene (TFE), vinylidene fluoride (VDF), and chlorotrifluoroethylene (CTFE).
[0027] In the present invention, the fluorine-containing polymer obtained by polymerization includes one or more comonomers selected from hexafluoropropylene (HFP), perfluoroalkylethylene monomers, and fluorovinyl ethers. Of these, the perfluoroalkylethylene monomer is one or more selected from tetrafluoroethylene (TFE), hexafluoropropylene (HFP), and vinylidene fluoride (VDF), and the fluorovinyl ether is perfluoroalkyl vinyl ether (PAVE), such as perfluoropropyl vinyl ether (PPVE), perfluoroethyl vinyl ether (PEVE), or perfluoromethyl vinyl ether (PMVE).
[0028] In specific embodiments, the comonomers are tetrafluoroethylene and perfluoropropylene, tetrafluoroethylene and perfluoroalkoxy vinyl ether, tetrafluoroethylene and perfluoropropylene and vinylidene fluoride, vinylidene fluoride and perfluoropropylene, and vinylidene fluoride and tetrafluoroethylene.
[0029] In a preferred embodiment, the content of the dispersant in water is 10 to 10,000 ppm, preferably 50 to 5,000 ppm, and more preferably 200 to 1,500 ppm.
[0030] In the above proposed technology, the water referred to is polymerization water.
[0031] In a preferred embodiment, the aqueous dispersion of the fluorine-containing polymer is an aqueous dispersion of polytetrafluoroethylene, an aqueous dispersion of polychlorotrifluoroethylene, or an aqueous dispersion of polyvinylidene fluoride.
[0032] Specifically, the above manufacturing method can be used to produce polytetrafluoroethylene (PTFE) homopolymers and modified PTFE dispersions. The PTFE homopolymers and modified PTFE dispersions generally contain at least 1 × 10⁻⁶ units. 8It has a melt viscosity of Pa·s, and at such a high melt viscosity, the flow of the polymer in the molten state is not significant, making it impossible to process and mold by melt processing methods. Polytetrafluoroethylene homopolymer refers to a high polymer obtained by polymerizing high-purity tetrafluoroethylene monomers, and there are no significant comonomers. Modified PTFE refers to a copolymer obtained by copolymerizing TFE with a low concentration of a second monomer, and the melting point of the resulting polymer is not significantly lower than the melting point of PTFE. The concentration of such comonomers is preferably less than 1% by weight, more preferably less than 0.5% by weight, and it is preferable to use a minimum amount of at least about 0.05% by weight to obtain a significant modification effect. Modified PTFE containing a small amount of comonomer has better film-forming properties during the sintering process. Suitable copolymer-modified monomers include fluorine-containing olefins and fluorine-containing vinyl ethers, such as perfluoropropylene (HFP) or perfluoroalkyl vinyl ether (PAVE), preferably perfluoroethyl vinyl ether (PEVE) and perfluoropropyl vinyl ether (PPVE). Furthermore, it may be modified with monomers such as chlorotrifluoroethylene (CTFE) and perfluorobutylethylene (PFBE).
[0033] The above manufacturing method can also be used to produce dispersions of melt-processable non-elastomer fluorine-containing polymers. Examples of such melt-processable non-elastomer fluorine-containing polymers include copolymers of polychlorotrifluoroethylene (PCTFE) or tetrafluoroethylene (TFE) with at least one fluorinated copolymerizable monomer (comonomer). The presence of a sufficient amount of the fluorinated copolymerizable monomer in the polymer causes the melting point of the copolymer to be significantly lower than that of a polytetrafluoroethylene (PTFE) homopolymer, for example, reducing the melting temperature to 315°C or below. A preferred melt-processable non-elastomer copolymer produced by the method according to the present invention comprises at least about 40 to 99 mol% of tetrafluoroethylene units and about 1 to 60 mol% of at least one other unit. Preferred comonomers containing TFE are perfluoroolefins having 3 to 8 carbon atoms, such as hexafluoropropylene (HFP) and perfluoroalkyl vinyl ether (PAVE).
[0034] The fluorine-containing polymer produced by the method according to the present invention comprises polymerization units from at least one fluorine-containing monomer, preferably a copolymer unit from at least one fluorine monomer and a copolymer unit from a second different monomer. The fluorine-containing monomer includes, but is not limited to, fluorine-containing olefins and fluorine-containing vinyl ethers.
[0035] The manufacturing method according to the present invention can also be used for the synthesis of polyvinylidene fluoride (PVDF) and copolymers of polyvinylidene fluoride, as well as for the synthesis of polyvinyl fluoride (PVF) and copolymers of vinyl fluoride.
[0036] The present invention also provides an aqueous dispersion of a fluorine-containing polymer produced by the method described above. [Effects of the Invention]
[0037] The polyether diacitic acid or salt-based surfactant provided in the present invention significantly reduces the surface tension of the polymerization system, improves the stability of aqueous dispersions of fluorine-containing polymers, and significantly reduces the amount of fluorine-containing surfactant used. [Modes for carrying out the invention]
[0038] The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.
[0039] In the examples, unless otherwise specified, all test methods and apparatus used are common in the art. Unless specific techniques or conditions are explicitly stated in the examples, they are carried out in accordance with the techniques and conditions described in the literature in the art or in the product instructions. Reagents and equipment whose manufacturers are not specified are all common products available through legitimate channels.
[0040] Embodiments of the present invention were carried out in a vertical or horizontal reactor equipped with a stirrer. The polymerization method was batch polymerization. In polymerization, deionized water was used as the dispersion medium, and gaseous TFE was introduced into the aqueous phase under stirring, and the polymerization reaction was initiated by bringing it into sufficient contact with a radical initiator in water under stirring and the action of a dispersant. In order to ensure the polymerization rate, it is necessary to ensure the pressure of the monomer in the reactor and to maintain the pressure in the polymerization reactor by replenishing the monomer after the start of the reaction. The reactor further includes a cooling jacket surrounding the reactor to control the temperature of the polymerization reaction by removing the heat of polymerization with cooling water.
[0041] In a typical polymerization method for PTFE homopolymers and modified PTFE, deionized water was first placed in a reactor as the polymerization medium, and paraffin was added as a stabilizer. The reactor was sealed, and the oxygen gas in the reactor was replaced with nitrogen gas so that the oxygen content was less than 30 ppm. Some or all of the dispersant was added and dispersed in the deionized water. The deionized water in the reactor was heated to the polymerization temperature by operating a stirrer. Some or all of the comonomer (e.g., HFP or perfluoroalkyl vinyl ether) was added, and then TFE was added and the reactor was pressurized to the polymerization pressure. A radical initiator solution, such as ammonium persulfate solution, was added. Succinic acid was used to reduce the formation of PTFE homopolymers and modified PTFE. A redox initiator system such as ammonium persulfate / sodium bisulfite may be used, in which case a lower polymerization temperature can be used. After the start of polymerization, TFE was continuously added to maintain the stability of the polymerization pressure. At each stage of polymerization, auxiliary agents such as comonomers, chain transfer agents, and some surfactants, as well as some initiators, may be added depending on the desired product performance.
[0042] When the amount of added monomer reached a predetermined value, the addition of TFE was stopped, the operation of the stirrer was stopped, the unpolymerized monomers in the reactor were recovered, nitrogen gas was blown into the reactor to replace the contents, and then the reactor was emptied. The resulting aqueous dispersion of fluorine-containing polymer was transferred to a storage tank and awaited further processing. The solid content of the aqueous dispersion of fluorine-containing polymer produced by the method according to the present invention is preferably at least about 10% by weight, and more preferably at least about 20% by weight. The solid content of the fluorine-containing polymer produced by the method according to the present invention is preferably in the range of about 20% by weight to about 40% by weight, and more preferably about 25% by weight to about 35% by weight.
[0043] In the preferred method of the present invention, the total weight of the undispersed fluorine-containing polymer (coagulation) produced during the polymerization process is less than 5% by weight of the stable fluorine-containing polymer dispersed in water, more preferably less than 1% by weight, and most preferably less than 0.5% by weight.
[0044] The aqueous dispersion of the fluorine-containing polymer obtained by polymerization according to the present invention can be used to obtain a fine powder with an average particle size of about 500 μm by a deemulsification and agglomeration method. Through a process flow such as washing and drying, a fluorine-containing dispersed resin product can be obtained that is used in fields such as the manufacture of films, fibers, and extruded tubes.
[0045] The aqueous dispersion of the fluorine-containing polymer obtained by polymerization according to the present invention can also be sold in aqueous dispersion form. Typically, the initial aqueous dispersion obtained by polymerization is concentrated, but before concentration, it is necessary to stabilize the aqueous dispersion by adding a nonionic surfactant, and then perform chemical concentration or vacuum concentration. The solid content of the concentrated aqueous dispersion of the fluorine-containing polymer is generally about 35% to 65% by weight.
[0046] The production of melt-processable fluorine-containing copolymers may employ similar polymerization processes, but unlike PTFE homopolymers and modified PTFE, they utilize large quantities of comonomers. The comonomers may be added to the reactor in batches during the polymerization process, or they may be uniformly mixed with the TFE monomers and then continuously added to the reactor. To improve the melt flow rate of melt-processable fluorine-containing copolymers, the molecular weight of the copolymer is typically controlled using chain transfer agents. A stable, concentrated aqueous dispersion of the fluorine-containing polymer can be produced by a concentration operation using an aqueous dispersion of the same fluorine-containing polymer. Furthermore, melt-processable fluorine-containing copolymers can be processed into granules or thin sheets through processes such as flocculation, washing, and drying.
[0047] Example 1 30 kg of deionized water, 1000 g of paraffin, and NH40 in a 50 L stainless steel reactor with stirring blades. 4 OOC-CH2CH2-(O-CH2CH2)3-O-CH2CH2-COONH 48g of surfactant A and 2g of CF3-OCF(CF3)-CF2-O-CH2CH2COONH4 (fluorine-containing surfactant B) were added, the reactor was sealed, and the system was purged three times with nitrogen gas and twice with TFE gas so that the oxygen content inside the reactor was less than 30 ppm. The reactor was heated, and when it reached 80°C, TFE was added so that the pressure inside the reactor was 2.0 MPa, and ammonium persulfate solution (an aqueous solution obtained by dissolving 60 mg of ammonium persulfate in 100 ml of deionized water) was added using a metering pump, and the stirring speed was set to 100 rpm. After the polymerization reaction started, the internal pressure of the reactor was maintained at 2.0 ± 0.05 MPa by continuously adding TFE. The polymerization heat was removed by flowing cooling water through the reactor jacket, and the polymerization temperature inside the reactor was stably maintained. When the added TFE reached 1.6 kg, 150 g of a mixed aqueous solution of surfactant A and fluorine-containing surfactant B (with a surfactant weight ratio of 4:1 and a content of 20% by weight) was added using a metering pump. When the amount of TFE consumed reached 13 kg, the addition of monomers and stirring were stopped, unreacted monomers in the reactor were recovered until the pressure reached a micro positive pressure, the reaction vessel was emptied to terminate the polymerization reaction, and aqueous dispersion A of PTFE was obtained. The polymer concentration was 29.9% by weight, and the particle size of the primary particles in the aqueous dispersion was 0.23 μm.
[0048] The resulting aqueous dispersion was condensed with an aqueous solution of saturated ammonium bicarbonate. The polymer was washed several times with warm water and filtered to obtain a polymer powder with an average particle size of 506 μm. This powder was dried in an oven at 180°C for 24 hours to obtain 12.85 kg of white polymer. A standard specific gravity test was performed, and the standard specific gravity of the polymer was found to be 2.173.
[0049] Example 2 30 kg of deionized water, 1000 g of paraffin, and NH40 in a 50 L stainless steel reactor with stirring blades. 4 OOC-CH2CH2-(O-CH2CH2)3-O-CH2CH2-COONH 44g of surfactant A and 1g of surfactant B (CF3-OCF(CF3)-CF2-O-CH2CH2COONH4) were added, the reactor was sealed, and the system was purged three times with nitrogen gas and twice with TFE gas so that the oxygen content inside the reactor was less than 30 ppm. The reactor was heated, and when it reached 80°C, TFE was added so that the pressure inside the reactor was 2.0 MPa, and ammonium persulfate solution (an aqueous solution obtained by dissolving 60 mg of ammonium persulfate in 100 ml of deionized water) was added using a metering pump, and the stirring speed was set to 100 rpm. After the polymerization reaction started, the internal pressure of the reactor was maintained at 2.0 ± 0.05 MPa by continuously adding TFE. The polymerization heat was removed by flowing cooling water through the reactor jacket, and the polymerization temperature inside the reactor was stably maintained. When the added TFE reached 1.6 kg, 75 g of a mixed aqueous solution of surfactant A and fluorine-containing surfactant B (with a surfactant weight ratio of 4:1 and a content of 20% by weight) was added using a metering pump. When the amount of TFE consumed reached 13 kg, the addition of monomers and stirring were stopped, unreacted monomers in the reactor were recovered until the pressure reached a micro positive pressure, the reaction vessel was emptied to terminate the polymerization reaction, and aqueous dispersion A of PTFE was obtained. The polymer concentration was 29.6% by weight, and the particle size of the primary particles in the aqueous dispersion was 0.26 μm.
[0050] The resulting aqueous dispersion was condensed with an aqueous solution of saturated ammonium bicarbonate. The polymer was washed several times with warm water and filtered to obtain a polymer powder with an average particle size of 557 μm. This powder was dried in an oven at 180°C for 24 hours to obtain 12.72 kg of white polymer. A standard specific gravity test was performed, and the standard specific gravity of the polymer was found to be 2.172.
[0051] Example 3 30 kg of deionized water, 1000 g of paraffin, and NH40 in a 50 L stainless steel reactor with stirring blades. 4 OOC-CH2CH2-(O-CH2CH2)5-O-CH2CH2-COONH 44g of surfactant A and 1g of surfactant B (CF3-OCF(CF3)-CF2-O-CH2CH2COONH4) were added, the reactor was sealed, and the system was purged three times with nitrogen gas and twice with TFE gas so that the oxygen content inside the reactor was less than 30 ppm. The reactor was heated, and when it reached 80°C, TFE was added so that the pressure inside the reactor was 2.0 MPa, and ammonium persulfate solution (an aqueous solution obtained by dissolving 60 mg of ammonium persulfate in 100 ml of deionized water) was added using a metering pump, and the stirring speed was set to 100 rpm. After the polymerization reaction started, the internal pressure of the reactor was maintained at 2.0 ± 0.05 MPa by continuously adding TFE. The polymerization heat was removed by flowing cooling water through the reactor jacket, and the polymerization temperature inside the reactor was stably maintained. When the added TFE reached 1.6 kg, 75 g of a mixed aqueous solution of surfactant A and fluorine-containing surfactant B (with a surfactant weight ratio of 4:1 and a content of 20% by weight) was added using a metering pump. When the consumption of TFE reached 13 kg, the addition of monomers and stirring were stopped, unreacted monomers in the reactor were recovered until the pressure reached a micro positive pressure, the reaction vessel was emptied to terminate the polymerization reaction, and aqueous dispersion A of PTFE was obtained. The polymer concentration was 29.7% by weight, and the particle size of the primary particles in the aqueous dispersion was 0.25 μm.
[0052] The resulting aqueous dispersion was condensed with an aqueous solution of saturated ammonium bicarbonate. The polymer was washed several times with warm water and filtered to obtain a polymer powder with an average particle size of 536 μm. This powder was dried in an oven at 180°C for 24 hours to obtain 12.75 kg of white polymer. A standard specific gravity test was performed, and the standard specific gravity of the polymer was found to be 2.170.
[0053] Example 4 30 kg of deionized water, 1000 g of paraffin, and NH40 in a 50 L stainless steel reactor with stirring blades. 4 OOC-CH2CH2-(O-CH2CH2)5-O-CH2CH2-COONH 44g of surfactant A and 1g of surfactant B (CF3-OCF(CF3)-CF2-O-CH2CH2COONH4) were added, the reactor was sealed, and the system was purged three times with nitrogen gas and twice with TFE gas so that the oxygen content inside the reactor was less than 30 ppm. 8g of perfluoropropylene was added to raise the temperature of the reactor, and when it reached 80°C, TFE was added so that the pressure inside the reactor was 2.0 MPa. Ammonium persulfate solution (an aqueous solution obtained by dissolving 80 mg of ammonium persulfate in 100 ml of deionized water) was added using a metering pump, and the stirring speed was set to 80 rpm. After the polymerization reaction started, the internal pressure of the reactor was maintained at 2.0 ± 0.05 MPa by continuously adding TFE. The polymerization heat was removed by flowing cooling water through the reactor jacket, and the polymerization temperature inside the reactor was stably maintained. When the added TFE reached 1.6 kg, 75 g of a mixed aqueous solution of 20% by weight surfactant A and fluorine-containing surfactant B (surfactant weight ratio 4:1) was added using a metering pump. When the amount of TFE consumed reached 13 kg, the addition of monomers and stirring were stopped, unreacted monomers in the reactor were recovered until the pressure reached a micro positive pressure, the reaction vessel was emptied to terminate the polymerization reaction, and an aqueous dispersion of PTFE A was obtained. The polymer concentration was 29.9% by weight, and the particle size of the primary particles in the aqueous dispersion was 0.25 μm.
[0054] The resulting aqueous dispersion was condensed with an aqueous solution of saturated ammonium bicarbonate. The polymer was washed several times with warm water and filtered to obtain a polymer powder with an average particle size of 533 μm. This was dried in an oven at 180°C for 24 hours to obtain 12.83 kg of white polymer. A standard specific gravity test was performed, and the standard specific gravity of the polymer was found to be 2.176, with an extrusion pressure of 23.2 MPa.
[0055] Example 5 30 kg of deionized water, 1000 g of paraffin, and NH40 in a 50 L stainless steel reactor with stirring blades. 4 OOC-CH2CH2-(O-CH2CH2)5-O-CH2CH2-COONH 44g of surfactant A and 1g of surfactant B (CF3-OCF(CF3)-CF2-O-CH2CH2COONH4) were added, the reactor was sealed, and the system was purged three times with nitrogen gas and twice with TFE gas so that the oxygen content inside the reactor was less than 30 ppm. 6g of perfluoropropyl vinyl ether (PPVE) was added, and the reactor was heated. When it reached 80°C, TFE was added so that the pressure inside the reactor was 2.0 MPa. Ammonium persulfate solution (an aqueous solution obtained by dissolving 80 mg of ammonium persulfate in 100 ml of deionized water) was added using a metering pump, and the stirring speed was set to 80 rpm. After the polymerization reaction started, the internal pressure of the reactor was maintained at 2.0 ± 0.05 MPa by continuously adding TFE. The polymerization heat was removed by flowing cooling water through the reactor jacket, and the polymerization temperature inside the reactor was stably maintained. When the added TFE reached 1.6 kg, 75 g of a mixed aqueous solution of 20% by weight surfactant A and fluorine-containing surfactant B (surfactant weight ratio 4:1) was added using a metering pump. When the amount of TFE consumed reached 13 kg, the addition of monomers and stirring were stopped, unreacted monomers in the reactor were recovered until the pressure reached a micro positive pressure, the reaction vessel was emptied to terminate the polymerization reaction, and an aqueous dispersion of PTFE A was obtained. The polymer concentration was 29.8% by weight, and the particle size of the primary particles in the aqueous dispersion was 0.24 μm.
[0056] The resulting aqueous dispersion was condensed with an aqueous solution of saturated ammonium bicarbonate. The polymer was washed several times with warm water and filtered to obtain a polymer powder with an average particle size of 566 μm. This was dried in an oven at 180°C for 24 hours to obtain 12.81 kg of white polymer. A standard specific gravity test was performed, and the standard specific gravity of the polymer was found to be 2.160, with an extrusion pressure of 24.1 MPa.
[0057] Comparative Example 1 30 kg of deionized water, 1000 g of paraffin, and 410 g of CF3-OCF(CF3)-CF2-O-CH2CH2COONH were added to a 50 L stainless steel reactor equipped with stirring blades. The reactor was sealed, and the system was purged three times with nitrogen gas and twice with TFE gas to reduce the oxygen content inside the reactor to less than 30 ppm. The reactor was heated to 80°C, at which point TFE was added to bring the reactor pressure to 2.0 MPa. Ammonium persulfate solution (an aqueous solution obtained by dissolving 60 mg of ammonium persulfate in 100 ml of deionized water) was added using a metering pump, and the stirring speed was set to 100 rpm. After the polymerization reaction started, the internal pressure of the reactor was maintained at 2.0 ± 0.05 MPa by continuously adding TFE. The polymerization heat was removed by circulating cooling water through the reactor jacket, and the polymerization temperature inside the reactor was stably maintained. When the added TFE reached 1.6 kg, 150 g of a 20 wt% ammonium perfluorooctanoate aqueous solution was added using a metering pump. When the TFE consumption reached 13 kg, the addition of monomers and stirring were stopped, unreacted monomers in the reactor were recovered until a micro positive pressure was reached, the reaction vessel was emptied to terminate the polymerization reaction, and aqueous dispersion A of PTFE was obtained. The polymer concentration was 29.7 wt%, and the particle size of the primary particles in the aqueous dispersion was 0.25 μm.
[0058] The resulting aqueous dispersion was condensed with an aqueous solution of saturated ammonium bicarbonate. The polymer was washed several times with warm water and filtered to obtain a polymer powder with an average particle size of 535 μm. This powder was dried in an oven at 180°C for 24 hours to obtain 12.75 kg of white polymer. A standard specific gravity test was performed, and the standard specific gravity of the polymer was found to be 2.169.
[0059] Comparative Example 2 30 kg of deionized water, 1000 g of paraffin, and 410 g of CF3-OCF(CF3)-CF2-O-CH2CH2COONH were added to a 50 L stainless steel reactor equipped with stirring blades. The reactor was sealed, and the system was purged three times with nitrogen gas and twice with TFE gas to reduce the oxygen content inside the reactor to less than 30 ppm. 8 g of perfluoropropylene was added to raise the temperature of the reactor. When the temperature reached 80°C, TFE was added to bring the reactor pressure to 2.0 MPa. Ammonium persulfate solution (a solution obtained by dissolving 80 mg of ammonium persulfate in 100 ml of deionized water) was added using a metering pump, and the stirring speed was set to 80 rpm. After the polymerization reaction started, the internal pressure of the reactor was maintained at 2.0 ± 0.05 MPa by continuously adding TFE. The polymerization heat was removed by circulating cooling water through the reactor jacket, and the polymerization temperature inside the reactor was stably maintained. When the added TFE reached 1.6 kg, 150 g of a 20 wt% ammonium perfluorooctanoate aqueous solution was added using a metering pump. When the TFE consumption reached 13 kg, the addition of monomers and stirring were stopped, unreacted monomers in the reactor were recovered until a micro positive pressure was reached, the reaction vessel was emptied to terminate the polymerization reaction, and aqueous dispersion A of PTFE was obtained. The polymer concentration was 30.0 wt%, and the particle size of the primary particles in the aqueous dispersion was 0.23 μm.
[0060] The resulting aqueous dispersion was condensed with an aqueous solution of saturated ammonium bicarbonate. The polymer was washed several times with warm water and filtered to obtain a polymer powder with an average particle size of 546 μm. This was dried in an oven at 180°C for 24 hours to obtain 12.85 kg of white polymer. A standard specific gravity test was performed, and the standard specific gravity of the polymer was found to be 2.175, with an extrusion pressure of 23.5 MPa.
[0061] Comparative Example 3 30 kg of deionized water, 1000 g of paraffin, and 410 g of CF3-OCF(CF3)-CF2-O-CH2CH2COONH were added to a 50 L stainless steel reactor equipped with stirring blades. The reactor was sealed, and the system was purged three times with nitrogen gas and twice with TFE gas to reduce the oxygen content inside the reactor to less than 30 ppm. 6.0 g of perfluoropropyl vinyl ether (PPVE) was added, and the reactor was heated. When the temperature reached 80°C, TFE was added to bring the reactor pressure to 2.0 MPa. Ammonium persulfate solution (a solution obtained by dissolving 80 mg of ammonium persulfate in 100 ml of deionized water) was added using a metering pump, and the stirring speed was set to 80 rpm. After the polymerization reaction started, the internal pressure of the reactor was maintained at 2.0 ± 0.05 MPa by continuously adding TFE. The polymerization heat was removed by circulating cooling water through the reactor jacket, and the polymerization temperature inside the reactor was stably maintained. When the added TFE reached 1.6 kg, 150 g of a 20 wt% ammonium perfluorooctanoate aqueous solution was added using a metering pump. When the TFE consumption reached 13 kg, the addition of monomers and stirring were stopped, unreacted monomers in the reactor were recovered until a micro positive pressure was reached, the reaction vessel was emptied to terminate the polymerization reaction, and aqueous dispersion A of PTFE was obtained. The polymer concentration was 29.9 wt%, and the particle size of the primary particles in the aqueous dispersion was 0.25 μm.
[0062] The resulting aqueous dispersion was condensed with an aqueous solution of saturated ammonium bicarbonate. The polymer was washed several times with warm water and filtered to obtain a polymer powder with an average particle size of 527 μm. This was dried in an oven at 180°C for 24 hours to obtain 12.8 kg of white polymer. A standard specific gravity test was performed, and the standard specific gravity of the polymer was found to be 2.157, with an extrusion pressure of 25.2 MPa. Although the present invention has been described in detail above through a general description, a mode for carrying out the invention, and a test, it will be apparent to those skilled in the art that several modifications or improvements may be made based on the present invention. Accordingly, any such modifications or improvements made without departing from the spirit of the present invention are all included within the scope of protection sought by the present invention. [Industrial applicability]
[0063] This invention provides a polyether diacitate or a salt-based surfactant and its use. The general structural formula of the polyether diacitate or salt-based surfactant is: XL-(O-CH2CHZ) a -(O-CR 1 R 2 CR 3 R 4 ) b -OLX(wherein Z represents H or CH3, L represents an alkylene group C1-C5, X represents -COOM or -SO3M, and M represents H) + NH4 + or Na + Represents R 1 ~R 4 The compounds are represented as follows: each independently represents a hydrogen atom, a fluorine atom, a non-fluorinated alkyl or alkoxy group, a partially fluorinated alkyl or alkoxy group, and a and b independently represent positive integers from 0 to 10. The polyether diacitates or salt-based surfactants provided in the present invention significantly reduce the surface tension of the polymerization system, improve the stability of aqueous dispersions of fluorine-containing polymers, and significantly reduce the amount of fluorine-containing surfactants used, thus offering good economic value and application prospects.
Claims
1. A polyether diacitate or a salt-based surfactant used as a dispersant for polymerization of fluorine-containing monomers, characterized by being one or two selected from the following structural formulas. NH ４ OOCC-CH ２ CH ２ -(O-CH ２ CH ２ ) ３ -O-CH ２ CH ２ -COONH ４ NH ４ OOCC-CH ２ CH ２ -(O-CH ２ CH ２ ) ５ -O-CH ２ CH ２ -COONH ４
2. Use of the polyether diacitate or salt-based surfactant described in claim 1 in the production of a fluorine-containing polymer.
3. The use according to claim 2, which is used in the production of an aqueous dispersion of a fluorine-containing polymer.
4. A dispersant comprising a polyether diacitate or a salt-based surfactant and a fluorine-containing surfactant as described in claim 1, The aforementioned fluorine-containing surfactant has a general structural formula: R ｆ -O-CZ １ Z ２ CZ ３ Z ４ -X (In the formula, R ｆ C １ ~C ５ Represents a perfluoroalkyl group or alkoxy group, Z １ ~Z ４ X represents a hydrogen atom or a fluorine atom, and X is -COOM or -SO ３ M represents H ＋ NH ４ ＋ or Na ＋ (This represents...) A dispersant characterized by being represented by the following: the law of nature,
5. The dispersant according to claim 4, characterized in that the fluorine-containing surfactant is one or more selected from the following structural formulas. CF ３ -O-CF(CF ３ )CF ２ -O-CH ２ CH ２ COOM CF ３ OCF ２ OCF ２ CF ２ -O-CH ２ CH ２ COOM CF ３ -OCF(CF ３ )CF ２ -O-CH ２ CH ２ SO ３ M CF ３ OCF ２ OCF ２ CF ２ -O-CH ２ CH ２ SO ３ M (In the formula, M is H) ＋ or NH ４ ＋ (This represents...)
6. The aforementioned fluorine-containing surfactant has the structural formula: CF ３ -OCF(CF ３ )-CF ２ -O-CH ２ CH ２ COONH ４ The dispersant according to claim 5, characterized in that it is represented by [a specific formula / method].
7. The dispersant according to claim 4, characterized in that the amount of the fluorine-containing surfactant used is 5 to 50% of the total mass of the dispersant.
8. The dispersant according to claim 7, characterized in that the amount of the fluorine-containing surfactant used is 10 to 30% of the total mass of the dispersant.
9. A method for producing an aqueous dispersion of a fluorine-containing polymer, characterized by comprising polymerizing at least one fluorine-containing monomer in an aqueous dispersion system using the dispersant described in any one of claims 4 to 8 as a dispersant.
10. The manufacturing method according to claim 9, characterized in that the content of the dispersant in water is 10 to 10,000 ppm.
11. The manufacturing method according to claim 10, characterized in that the content of the dispersant in water is 50 to 5000 ppm.
12. The manufacturing method according to any one of claims 9 to 11, characterized in that the aqueous dispersion of the fluorine-containing polymer is an aqueous dispersion of polytetrafluoroethylene, an aqueous dispersion of polychlorotrifluoroethylene, or an aqueous dispersion of polyvinylidene fluoride.