Fluororesin composition and method for producing same

Abstract

A composition is disclosed that includes a PVDF polymer, 0.01-3% of one or more quaternary organic salts, and 10-1000 ppm of one or more dispersants, and has reduced optical haze, a high melting temperature, and a high elastic modulus. Also disclosed is a method for producing the composition.

Description

[Technical field]

[0001] The present invention provides a composition and method capable of finely dispersing a quaternary organic salt in a fluoropolymer, the composition providing a fluoropolymer having high transparency, high melting temperature and high modulus. [Background technology]

[0002] 2. Background of the Invention It is known that PVDF polymers with high transparency can be produced by blending PVDF with acrylic polymers or blending PVDF with quaternary ammonium salts, but both of these methods result in a decrease in the melting temperature of the PVDF polymer, as well as a decrease in the elastic modulus of the polymer in the case of quaternary ammonium salts.

[0003] Quaternary ammonium salts have been described to improve transparency in PVDF polymers, but have been shown to reduce the melting temperature and modulus of the polymer. Phosphonium, imidazolium, and ammonium organic salts increase the melting temperature in PVDF polymers, but have not been reported to improve transparency.

[0004] US Patent No. 6,610,766 describes the use of alkyl quaternary ammonium sulfates or sulfites with PVDF to increase the electrical resistivity of the polymer. It also describes improving the transparency of PVDF. Its examples and especially Figure 4 show that the melting temperature decreases with increasing amounts of ammonium salt added.

[0005] WO 2020 / 137108 and WO 2013 / 7116 further describe the use of alkyl quaternary ammonium sulfates or sulfites with PVDF. These compositions achieve good transparency and inhibit yellowing of thick sections by having an alkali metal concentration of 60 ppm or less in the polyvinylidene fluoride resin composition, a hydrogen fluoride concentration of 5 ppm or less in the polyvinylidene fluoride, and / or a rate of non-uniform bonds in the polyvinylidene fluoride of 4% or more. In some examples, Kynar® PVDF resins such as Kynar 1000HD containing residual surfactants with acid end groups are used. There is no mention of the melting temperature of PVDF being increased by the addition of quaternary ammonium salts.

[0006] WO 2007 / 145668 describes the use of onium salts with PVDF. The compositions are annealed at high temperatures and / or the onium salts are modified with nanoclay to achieve compositions with piezoelectric properties, high melting temperatures and low flexural modulus. There is no mention of the onium salts imparting transparency to the PVDF composition.

[0007] It is also known that the use of high temperature annealing in PVDF polymers increases the melting temperature of the polymer. An example is shown in a paper by Gregorio et al. (Journal of Materials Science, 35, 2000) which states that for PVDF homopolymers, the phase transition from α to γ ​​occurs in the solid state at temperatures of at least 155°C, which is about 10-20°C lower than the typical melting temperature of PVDF in the α phase. The transition from α to β phase increases the melting temperature by 5-10°C. Annealing can be used to improve the transparency of PVDF.

[0008] WO 2015 / 048697 describes the use of ammonium and phosphonium salts with PVDF containing residual surfactants with acid end groups. The salts are said to react with the acid end groups and improve the color stability of the product after melt processing. Preferred salts are quaternary ammonium halides. No mention is made of the effect of the salts on the transparency, melt temperature, or modulus of the polymer.

[0009] The problem faced was to provide a PVDF polymer with high transparency and high melting point, which maintains at least 65%, preferably 70%, more preferably 75% modulus, preferably storage modulus. Known methods for producing PVDF with high transparency include blending PVDF with acrylic polymers or blending PVDF with quaternary ammonium salts. Both approaches result in a decrease in the melting point of the PVDF polymer and a decrease in other properties such as the modulus of the polymer. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] U.S. Patent No. 6,610,766 [Patent Document 2] International Publication No. 2020 / 137108 [Patent Document 3] WO 2013 / 7116 [Patent Document 4] International Publication No. 2007 / 145668 [Patent Document 5] International Publication No. 2015 / 048697 [Non-patent literature]

[0011] [Non-Patent Document 1] Journal of Materials Science,35,2000 Summary of the Invention [Problem to be solved by the invention]

[0012] It has been unexpectedly found that when a PVDF polymer is combined with a quaternary salt and a suitable dispersing agent is present (preferably a copolymer containing blocks of ethylene oxide and propylene oxide, or a sulfate and sulfonate type salt), the resulting polymer has high transparency (haze less than 40% at 1 mm), a melting point at least 2°C higher and up to 7°C higher than the initial PVDF polymer, and a modulus that is retained at least 65%, preferably at least 75%, of the initial PVDF polymer. [Means for solving the problem]

[0013] Summary of the Invention The present invention is a composition and method for providing a PVDF ("polyvinylidene fluoride") polymer composition having high transparency, high melting temperature, and high modulus by modifying the PVDF polymer with a quaternary organic salt in the presence of a dispersing agent.

[0014] Surprisingly, it has been found that modifying PVDF polymer with a quaternary organic salt in the presence of a dispersing agent reduces the optical haze to less than 40% (1 mm thick section), retains greater than 65% modulus, and increases the melting temperature of the PVDF polymer by at least 2° C., thereby enabling a higher use temperature for the material. Without being limited by theory, it is believed that the dispersing agent is necessary to aid in the diffusion of the quaternary organic salt to the interface between the amorphous and crystalline domains of the PVDF polymer, thereby maximizing the nucleation effect on the transparency of the polymer without adversely affecting the melting temperature and modulus discussed above.

[0015] The present invention relates to a polyvinylidene fluoride composition having high transparency, high melting temperature and high modulus, comprising (a) a polyvinylidene fluoride polymer, (b) 10 ppm to 1000 ppm by weight of a dispersant based on the weight of the polyvinylidene fluoride polymer, and (c) 0.1 to 3% by weight of one or more quaternary organic salts (nucleating additives) based on the weight of the polyvinylidene fluoride polymer. Preferably, the composition comprises more than 60% by weight, preferably more than 80% by weight, more preferably more than 90% by weight of PVDF polymer based on the total solids content in the composition.

[0016] The present invention provides a method for producing a fluoroplastic with low optical haze, high melting temperature and high modulus, comprising adding a quaternary organic salt (nucleating additive) to a fluoroplastic with a dispersing agent present in the composition. The present invention also provides a method for producing a composition with low optical haze of less than 40%, preferably less than 35%, more preferably less than 30%, as measured by ASTM D1003 on a 1 mm section compression molded using the composition. It has been found that the efficient use of selected quaternary organic salts in PVDF polymers in conjunction with non-fluorinated and acid group-free dispersing agents reduces optical haze and surprisingly increases the melting temperature of the polymer while still providing high modulus retention. The present invention provides the use of dispersing agents to promote the diffusion of the quaternary organic salt in the polymer composition. Dispersion of the quaternary organic salt is a challenge, especially for some PVDF copolymers, due to the hydrophobic nature of the PVDF polymer. Poor dispersion of the quaternary organic salt can result in high optical haze due to the size of the quaternary organic salt itself in the final material. The dispersant is a quaternary organic salt that is present in the composition as small particles and is capable of diffusing to the interface between the amorphous and crystalline domains of the PVDF polymer.

[0017] Aspects of the invention Aspect 1: A resin composition comprising: (a) vinylidene fluoride polymers in which VDF accounts for more than 60% by weight, preferably more than 70% by weight, of all monomer units; (b) 0.1 to 3 weight percent, based on the weight of the polyvinylidene fluoride polymer, of one or more quaternary organic salts, and (c) 10 to 1000 ppm (by weight) of one or more amphipathic dispersants that do not contain fluorine atoms or acid groups. Including, The resin composition, wherein a 1 mm thick section compression molded at 230°C has an optical haze of less than 40% according to ASTM D1003.

[0018] Aspect 2: The resin composition of aspect 1, wherein the resin composition has a melting temperature that is at least 2° C. higher than the same PVDF resin composition except that it does not contain the quaternary organic salt, and has at least 65% retention of elastic modulus compared to the same composition except that it does not contain the quaternary organic salt.

[0019] Aspect 3: A resin composition according to Aspect 1 or 2, wherein the vinylidene fluoride polymer is a homopolymer or a copolymer having at least one comonomer selected from the group consisting of hexafluoropropene, 2,3,3,3-tetrafluoropropylene, and 3,3,3-trifluoropropene.

[0020] Aspect 4: The resin composition according to any one of Aspects 1 to 3, wherein the vinylidene fluoride polymer is a copolymer containing hexafluoropropylene.

[0021] Aspect 5: The resin composition according to any one of Aspects 1 to 4, comprising a total of 0.2 to 3 wt %, more preferably 0.3 to 2 wt %, of a quaternary organic salt based on the total weight of (a)+(b)+(c).

[0022] Aspect 6: The resin composition according to any one of Aspects 1 to 5, comprising a dispersant in a total amount of 10 ppm to 500 ppm based on the total weight of (a)+(b)+(c).

[0023] Aspect 7: The resin composition according to any one of Aspects 1 to 6, wherein the optical haze of a portion having a thickness of 1 mm that is compression molded at 230° C. is less than 35%, and more preferably less than 30%.

[0024] Aspect 8: The resin composition of any one of Aspects 1 to 7, wherein the melting temperature of the resin composition is at least 3° C. higher, more preferably at least 5° C. higher, than the melting temperature of the same composition except that it does not contain the quaternary organic salt.

[0025] Aspect 9: The resin composition of any of Aspects 1-8, wherein the resin composition has a modulus retention of at least 70%, more preferably at least 75%, compared to the same composition except that it does not contain the quaternary organic salt.

[0026] Aspect 10: The dispersant is a nonionic block copolymer containing a segment of polyethylene glycol, polypropylene glycol and / or polytetramethylene glycol, the nonionic block copolymer having 2 to 200 repeating units per block; Poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) having 2 to 200 repeat units per block arranged in an ABA triblock structure; Alkyl phosphonates, polyvinyl phosphonates, polyvinyl sulfonates, C7~C20 alkane sulfonates, Alkyl aryl sulfonates, aryl sulfonates, Alkanesulfonates, and Combinations of these 10. The resin composition according to any one of aspects 1 to 9, selected from the group consisting of:

[0027] Aspect 11: The resin composition of any one of Aspects 1 to 10, wherein the dispersant is a block copolymer and includes at least one block of poly(ethylene glycol) or at least one block of poly(propylene glycol).

[0028] Aspect 12: The resin composition of any one of Aspects 1 to 10, wherein the dispersant comprises a block copolymer having poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) groups.

[0029] Aspect 13: The resin composition of any one of Aspects 1 to 10, wherein the dispersant includes at least one of sodium lauryl sulfate, sodium laureth sulfate, sodium octyl sulfate, potassium lauryl sulfate, ammonium lauryl sulfate, sodium octyl sulfonate, potassium octyl sulfonate, ammonium octyl sulfonate, and mixtures thereof.

[0030] Aspect 14: The resin composition of any one of Aspects 1 to 13, wherein the quaternary organic salt is selected from the group consisting of quaternary ammonium salts, quaternary phosphonium salts, and combinations thereof.

[0031] Aspect 15: The composition of any of aspects 1-13, wherein the quaternary organic salt is selected from the group consisting of tetrabutylammonium bisulfate, heptyltriphenylphosphonium bromide, (2-hydroxyethyl)triphenylphosphonium bromide, (4-carboxybutyl)triphenylphosphonium bromide, and tetrabutylammonium tetrafluoroborate, and combinations thereof.

[0032] Aspect 16: A method for producing the resin composition according to any one of aspects 1 to 15, comprising the steps of: (a) preparing a PVDF polymer; (b) mixing a quaternary organic salt with a dispersing agent; (c) mixing the blend of (b) with the PVDF polymer of (a); Including, The amount of said quaternary organic salt is at least 0.1% by weight and not more than 3% by weight, based on the weight of the total dry composition, and the amount of said dispersing agent in the final composition is from 10 ppm to 1000 ppm (by weight), based on the weight of the total dry composition.

[0033] Aspect 17: A method for producing the resin composition according to any one of aspects 1 to 15, comprising the steps of: (d) providing a composition having a PVDF polymer and a dispersant in the form of a latex; (e) blending a quaternary organic salt with the latex to form a blend; (f) drying the blend of (e) to form a solid material. Including, The amount of said quaternary organic salt is at least 0.1% by weight and not more than 3% by weight, based on the weight of the total dry composition, and the amount of said dispersing agent in the final composition is from 10 ppm to 1000 ppm (by weight), based on the weight of the total dry composition.

[0034] Aspect 18: A method for producing the resin composition according to any one of aspects 1 to 15, comprising the steps of: (g) providing a composition having a PVDF polymer and a dispersing agent as a latex; (h) drying the latex to form a solid material; (i) blending a quaternary organic salt with the PVDF composition of (g) above; Including, The amount of said quaternary organic salt is at least 0.1% by weight and not more than 3% by weight, based on the weight of the total dry composition, and the amount of said dispersing agent in the final composition is from 10 ppm to 1000 ppm (by weight), based on the weight of the total dry composition.

[0035]

[0041] Aspect 19: An article comprising the resin composition of any of Aspects 1-15, wherein the article can be a film, a sheet, a rod, or a multilayer part.

[0036] Example 20: The article of example 19, wherein the article is a melt-processed article. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] Detailed Description of the Invention All documents cited in this application are incorporated herein by reference.

[0038] As used herein, percentages are weight percent unless otherwise specified, and molecular weights are weight average molecular weight unless otherwise specified. Melt viscosity (MV) is measured at 230° C., 100 seconds using ASTM D-3835. -1 It is measured in.

[0039] "Copolymer" means a polymer having two or more different monomer units. "Polymer" is used to mean both homopolymers and copolymers. For example, as used herein, "PVDF" and "polyvinylidene fluoride" are used to mean both homopolymers and copolymers unless otherwise specified. Polymers may be linear, branched, star, comb, block, or other structures. Polymers may be homogeneous, where the majority of polymer chains have a similar distribution of comonomer units, heterogeneous, where different polymer chains have widely different comonomer unit distributions and some chains have no comonomer units, and gradient, where polymer chains have a gradient distribution of comonomer units along the chain.

[0040] Amphiphilic means that the molecule has both hydrophobic (non-polar) and hydrophilic (polar) regions. Common examples of amphiphilic compounds are those known to be excellent surfactants in aqueous colloidal systems, such as those used in emulsion and suspension polymerization.

[0041] PVDF polymer In the present invention, a PVDF homopolymer or copolymer is used.

[0042] The term "PVDF copolymer" refers to a copolymer of vinylidene fluoride (VDF) with one or more other fluorinated or non-fluorinated comonomers, preferably a fluorinated comonomer. The PVDF copolymer of the present invention is one in which the vinylidene fluoride units account for more than 60% of the total weight of all monomer units in the polymer, more preferably more than 70% of the total weight of such units, and most preferably more than 75% of the total weight of such units. The fluorinated comonomer preferably accounts for at least 0.5% by weight of the PVDF copolymer, preferably at least 1% by weight, more preferably at least 4% by weight. The fluorinated comonomer is preferably between 0.5% and 30% by weight, more preferably between 1% and 20% by weight.

[0043] The fluorinated comonomer is selected from compounds that contain a vinyl group that can be opened to be polymerized and that contain at least one fluorine atom, at least one fluoroalkyl group, or at least one fluoroalkoxy group directly bonded to the vinyl group, with the exception of VDF, which is already present in the PVDF copolymer. Examples of fluorinated comonomers include, but are not limited to, vinyl fluoride; trifluoroethylene (VF3); chlorotrifluoroethylene (CTFE); 1,2-difluoroethylene; tetrafluoroethylene (TFE); hexafluoropropylene (HFP); 2,3,3,3-tetrafluoropropylene; 1,3,3,3-tetrafluoropropylene; 3,3,3-trifluoropropylene; perfluoro(alkyl vinyl) ethers such as perfluoro(methyl vinyl) ether (PMVE), perfluoro(ethyl vinyl) ether (PEVE), and perfluoro(propyl vinyl) ether (PPVE); perfluoro(1,3-dioxole); and perfluoro(2,2-dimethyl-1,3-dioxole) (PDD). Preferred PVDF copolymers include copolymers of VDF and HFP, copolymers of VDF and 2,3,3,3-tetrafluoropropylene, copolymers of VDF and 3,3,3-trifluoropropylene, and terpolymers of VDF, HFP and TFE.

[0044] The PVDF copolymer can be a copolymer of VDF and HFP. In one embodiment, the copolymer has at least 1% to 30% by weight, preferably up to 25% by weight, more preferably up to 15% by weight, of hexafluoropropene (HFP) units.

[0045] The PVDF copolymer may have at least 70% by weight of VDF units, preferably at least 75% by weight, more preferably at least 85% by weight.

[0046] The PVDF copolymers for use in the present invention have a high molecular weight. As used herein, high molecular weight means a PVDF copolymer that is viscoelastic at 230° C. and 100 seconds. -1 By "melt viscosity" we mean having a melt viscosity, as measured in accordance with ASTM method D-3835, of greater than 1.0 kpoise, preferably greater than 5 kpoise, and more preferably greater than 10 kpoise.

[0047] The PVDF copolymers used in the present invention are generally made by means known in the art using aqueous free radical emulsion polymerization, although suspension polymerization, solution polymerization, and supercritical CO2 polymerization processes may also be used.

[0048] In a typical emulsion polymerization process, a reactor is charged with deionized water, a water-soluble surfactant capable of emulsifying the reactant mass during polymerization, and optionally a paraffin wax antifouling agent. In some polymerizations, no surfactant is used. The mixture is stirred and deoxygenated. A predetermined amount of chain transfer agent (CTA) is then introduced into the reactor, the temperature of the reactor is raised to a desired level, and vinylidene fluoride and optionally one or more comonomers are fed into the reactor. Once the initial charge of vinylidene fluoride and optional comonomers has been introduced and the pressure in the reactor has reached a desired level, an initiator emulsion or initiator solution is introduced to start the polymerization reaction. The temperature of the reaction may vary depending on the characteristics of the initiator used, but one skilled in the art would know how to do so. Typically, the temperature is about 30°C to 150°C, preferably about 60°C to 120°C. Once the desired amount of polymer is reached in the reactor, the monomer feed is stopped, but the initiator feed is optionally continued to consume the residual monomer. Residual gases (including unreacted monomers) are vented and the latex is recovered from the reactor.

[0049] The surfactants used in the polymerization are non-fluorosurfactants known to those skilled in the art to be useful in PVDF emulsion polymerization. The PVDF polymer emulsion of the present invention does not contain a fluorosurfactant, and no fluorosurfactants are used in any part of the polymerization. The surfactants used in the polymerization also do not contain acid groups, as such groups have been shown to interact poorly with the quaternary organic salts of the present invention and prevent the desired property enhancement of the PVDF polymer. The non-fluorinated, acid-free surfactants useful in the PVDF polymerization of the present invention can be both ionic and non-ionic in nature, examples of which include, but are not limited to, sodium alkyl sulfates, sodium aryl sulfates, sodium alkyl sulfonates, sodium aryl sulfonates, polyvinyl sulfonates, polyethylene glycols and / or polypropylene glycols, and block copolymers thereof, and siloxane-based surfactants. In one embodiment, the emulsion polymerization is surfactant-free.

[0050] PVDF polymerization generally results in a latex having a solids level of 10-60% by weight, preferably 10-50% by weight, and a latex volume average particle size of less than 500 nm, preferably less than 400 nm, more preferably less than 300 nm. The discrete volume average particle size is generally at least 20 nm, preferably at least 50 nm.

[0051] To improve freeze-thaw stability, the PVDF latex may be mixed with small amounts (preferably less than 10% by weight, more preferably less than 5% by weight) of one or more other water-miscible solvents, such as ethylene glycol.

[0052] The PVDF latex may be used in the process of the present invention as is or may first be dried to a powder by means known in the art, including but not limited to spray drying, freeze drying, coagulation, drum drying, etc.

[0053] In some embodiments, a copolymer of VDF and HFP is used. In some embodiments, a homopolymer of VDF is used.

[0054] It is preferred that no fluorinated molecules other than the PVDF polymer are present in the composition.

[0055] Quaternary Organic Salts The quaternary organic salt acts as a nucleating additive for PVDF.

[0056] The quaternary organic salt is used in an amount of 0.1-3% by weight. The quaternary organic salt contains a quaternary cationic center that forms four covalent bonds, each bond to an alkyl or aryl group. The quaternary cationic center can be ammonium, phosphonium, or pyridinium. Examples of quaternary organic salts include alkyl and aryl ammonium salts, alkyl and aryl phosphonium salts, alkyl and aryl pyridinium salts, tetrabutylammonium bisulfate, heptyltriphenylphosphonium bromide, (2-hydroxyethyl)triphenylphosphonium bromide, (4-carboxybutyl)triphenylphosphonium bromide, and tetrabutylammonium tetrafluoroborate.

[0057] One or more quaternary organic salts may be present. The total amount of quaternary organic salts in the present invention is at least 0.1% and not more than 3% by weight based on the total composition. The amount of any one quaternary organic salt may be 0.1-3% by weight, preferably 0.2-3% by weight, more preferably 0.3-2% by weight based on the total composition.

[0058] Dispersants The amount of dispersant present in the composition of the present invention is from 10 ppm to 1000 ppm (by weight) of one or more dispersants, preferably from 10 ppm to 500 ppm, based on the total composition. The dispersant is amphiphilic. The term "dispersant" refers to a class of molecules that have both hydrophobic and hydrophilic moieties and are capable of stabilizing and dispersing hydrophobic molecules and aggregates of hydrophobic molecules in aqueous systems.

[0059] The dispersant does not include compounds containing fluorine atoms. The dispersant does not include compounds containing acid groups.

[0060] The dispersant is a non-fluorinated compound, i.e., the dispersant does not contain fluorine atoms. Fluorinated compounds do not provide good dispersion of the nucleating additive. Fluorinated dispersants have too high an affinity for fluororesins to function as dispersing aids for quaternary organic salts.

[0061] Dispersants containing acids do not function as dispersants in the present invention because the acid groups have too much polarity and do not have sufficient affinity with the PVDF resin, and instead have a detrimental effect on the dispersion of the quaternary organic salt.

[0062] Examples of non-fluorinated, acid-free dispersants include: non-ionic block copolymers containing segments of polyethylene glycol, polypropylene glycol and / or polytetramethylene glycol having 2 to 200 repeating units per block; Poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) having 2 to 200 repeat units per block arranged in an ABA triblock structure; Alkyl phosphonates, polyvinyl phosphonates, polyvinyl sulfonates, C7~C20 alkane sulfonates, Alkyl aryl sulfonates, aryl sulfonates, Alkane sulfates, and combinations thereof.

[0063] For non-ionic block copolymers containing segments of polyethylene glycol, polypropylene glycol and / or polytetramethylene glycol, the repeat units are preferably 3-100 in each block, and the end groups are preferably selected from hydrogen, hydroxyl, carboxyl, ester, ether and / or hydrocarbon. Also, poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) are preferably arranged in an ABA triblock structure with 2-200 repeat units per block, i.e., giving PEO-PPO-PEO.

[0064] Ionic dispersants exclude quaternary organic salts that contain a quaternary cationic center with four covalent bonds to alkyl or aryl groups, such as ammonium, phosphonium, pyridinium, etc. Quaternary ammonium cations have the structure NR +4 (R is an alkyl or aryl group). None of the four bonds are to hydrogen. The ammonium ion (NH4 + ) and primary, secondary, and tertiary ammonium cations, quaternary ammonium cations are permanently charged, regardless of the pH of their solution.

[0065] Ammonium cations for the dispersants used in the present invention include NH4, and monoalkyl, dialkyl, and trialkyl ammonium ions, where the alkyl moieties of the monoalkyl, dialkyl, or trialkyl ammonium ions each independently have a C1 to C20 alkyl group, preferably each alkyl group independently has 1 to 4 carbon atoms. Examples of alkyl phosphonates, polyvinyl phosphonates, and polyvinyl sulfonates include, but are not limited to, ammonium octyl phosphonate, ammonium dodecyl phosphonate, sodium octyl phosphonate, sodium dodecyl phosphonate, salts of polyvinyl phosphonic acid, such as the sodium, potassium, or magnesium salts, and salts of polyvinyl sulfonic acid, such as the sodium, potassium, or magnesium salts.

[0066] Alkanesulfonates include, but are not limited to, C7 to C20 straight chain 1-alkanesulfonates, C7 to C20 straight chain 2-alkanesulfonates, C7 to C20 straight chain 1,2-alkanedisulfonates, and mixtures thereof.

[0067] Alkylarylsulfonates include, but are not limited to, sodium dodecylbenzenesulfonate or ammonium dodecylbenzenesulfonate (SDDBS). The alkyl group can be C1-C20. The aryl group is generally benzene or a benzene derivative.

[0068] Alkane sulfates (also called alkyl sulfates) follow a general structure such as R-OSOM or MOSO-R-OSOM, where R is a hydrocarbon group and M is a monovalent cation preferably selected from the group consisting of an alkali metal ion, an ammonium ion, a monoalkyl, dialkyl, and a trialkylammonium ion, the alkyl portions of the monoalkyl, dialkyl, or trialkylammonium ion each independently having a C1-C20 alkyl group, preferably each alkyl group independently having 1-4 carbon atoms. Preferred M is selected from sodium, potassium, and ammonium. Examples include, but are not limited to, sodium lauryl sulfate, sodium octyl sulfate, potassium lauryl sulfate, ammonium lauryl sulfate, sodium laureth sulfate, and mixtures thereof.

[0069] Particularly preferred dispersants include blocks of PEG and PPG, such as poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol), PPG-PEG-PPG, or PEO-PPO-PEO. Examples of this type of surfactant are available under the trademark PLURONIC.

[0070] Mixing Process PVDF polymers are produced in the presence of non-fluorinated, acid-free dispersants or surfactant-free processes, and generally the polymer composition will contain residual dispersants when used. Optionally, additional dispersants can be added to the polymer composition after the polymerization process. If there is sufficient residual dispersant in the PVDF polymer from the polymerization process, the addition of dispersants is optional. Optionally, the residual dispersant used to produce the polymer is washed out of the polymer and the same or a different dispersant is added to the polymer after the polymerization process. The PVDF polymer, the quaternary organic salt, and the dispersant (residual from the polymerization and / or post-added) can be mixed in an aqueous medium and then dried to a particulate material, or they can be mixed as a solid ("dry") material. These components can be blended in any order or simultaneously. The dispersant can be mixed with the PVDF polymer and the quaternary organic salt in one step, or it can be mixed first with the quaternary organic salt and then with the PVDF polymer, or it can be mixed first with the PVDF polymer and then with the quaternary organic salt. Any mixing equipment known in the art can be utilized, including static mixers, Brabenders, and extruders.

[0071] In one embodiment, the blend of PVDF polymer, quaternary organic salt and dispersant can be produced by co-spray drying these components mixed in an aqueous medium. Effective amounts of PVDF polymer latex, quaternary organic salt (in latex, solution or solid state), and residual and / or post-added dispersant (in latex, solution or solid state) can be mixed and co-sprayed to achieve a well-mixed dry powder at the nanoscale. This co-spray dried composite can then be processed into the desired shape by any melt process known in the art, such as compression molding, injection molding, extrusion, co-extrusion, etc. The use of PVDF latex with small particle size (usually 20-400 nm) to produce the blend of the present invention results in a very intimate blend that helps to better disperse the nucleating additive in the material and further reduce optical haze.

[0072] Characterization of the compositions of the present invention The optical haze value of the polymer composition of the present invention is less than 40%, preferably less than 35%, more preferably less than 30%, as measured on a 1 mm thick PVDF section containing a dispersant and a quaternary organic salt.

[0073] The melting temperature of the polymeric composition of the present invention is at least 2°C, preferably 3°C, and more preferably at least 5°C higher than the melting temperature of the same composition but without the quaternary organic salt.

[0074] The elastic modulus of the compositions of the present invention comprising a dispersant and a quaternary organic salt has at least 65% retention of the elastic modulus, preferably greater than 70%, and even more preferably greater than 75% retention of the elastic modulus (preferably storage modulus) compared to the same composition but without the quaternary organic salt.

[0075] Not only do the compositions of the present invention have a high melting temperature and are able to retain greater than 65% of the modulus, but they also unexpectedly exhibit reduced optical haze, making them novel in their possessing all three properties, as improving one property typically comes at the expense of another.

[0076] Purpose The advantageous properties of PVDF polymer, including chemical inertness, biological purity, and excellent mechanical and thermomechanical properties, combined with consistent low haze, high melt temperature, and high modulus, allow the compositions of the present invention to be used in many applications.

[0077] The compositions of the present invention are melt processed to produce articles.The articles of the present invention are melt processed articles.

[0078] Some articles made from the compositions of the present invention include, but are not limited to, films, sheets, rods, pipes, tubes, and multi-layer parts. EXAMPLES

[0079] Test Method: Optical haze was measured according to ASTM D1003 and is reported as the percent optical haze for a part of a given thickness. A thickness of 1 mm was used in the examples.

[0080] Melt temperatures are measured by differential scanning calorimetry (DSC) using a TA Instruments Q2000 unit and ASTM E794. DSC runs are cycled twice from minus 75°C (198 Kelvin) to 210°C at 10°C / min, and the melt temperature is reported as the melt temperature peak (lowest temperature peak if there are multiple peaks) during the second thermal cycle. A material containing both a nucleating agent and a dispersing aid (Material X) is compared to an identical material (Material Y) except that it does not contain a nucleating agent. The increase or decrease in melt temperature is calculated as the difference between the melt temperature of Material X and the melt temperature of Material Y, and is expressed in degrees Celsius (°C).

[0081] The elastic modulus at room temperature is determined by various methods to measure either Young's modulus or storage modulus. Young's modulus is measured in tension mode according to ASTM D638 using an Instron 4202 instrument or a TA Instruments RSA-G2 analyzer. Storage modulus is obtained from dynamic mechanical analysis (DMA) in torsion mode according to ASTM D5279 using a TA Instruments ARES RDA III at a heating rate of 5°C / min. A material containing both a nucleating agent and a dispersing aid (material X) is compared to the same material (material Y) except that it does not contain a nucleating agent. The retention of elastic modulus is calculated as the ratio of the elastic modulus of material X to that of material Y. It is expressed as a percentage.

[0082] Example 1: PVDF homopolymer containing 300 ppm of Pluronic block copolymer of polyethylene glycol and polypropylene glycol is mixed with 1.5% tetrabutylammonium bisulfate at 200° C. in a twin screw extruder to produce pellets. The pellets are compression molded into 1 mm thick plaques at 220° C. under 5 MT pressure and cooled to room temperature over 10 minutes. A control 1 mm plaque of material without tetrabutylammonium bisulfate is also compression molded under the same conditions. Table 1 shows the optical haze, melting point and modulus of the materials. The optical haze of the material of Example 1 is 21.4%, which represents a retention of 77% relative to the control. Additionally, the material of Example 1 shows a 4.9° C. increase in melting point and 80-81% modulus retention compared to the control.

[0083] Example 2: PVDF homopolymer containing 300 ppm of sodium 1-octanesulfonate is mixed with 1.5% tetrabutylammonium bisulfate in a twin screw extruder at 200° C. to produce pellets. The pellets are compression molded into 1 mm thick plaques at 220° C. under 5 MT pressure and cooled to room temperature over 10 minutes. A control 1 mm plaque of material without tetrabutylammonium bisulfate is also compression molded under the same conditions. Table 1 shows the optical haze, melting point and modulus of the materials. The reduction in optical haze is 75%, the increase in melting point is 6.2° C., and the retention of storage modulus is 79-88%. The optical haze of the material of Example 2 is 24.4%, which represents a retention of 75% relative to the control. Additionally, the material of Example 2 shows a 6.2° C. increase in melting point and a retention of modulus of 79-88% compared to the control.

[0084] Example 3: VDF / HFP copolymer containing 300 ppm Pluronic block copolymer of polyethylene glycol and polypropylene glycol is mixed with 0.5% tetrabutylammonium bisulfate in a twin screw extruder at 200° C. to produce pellets. The pellets are compression molded into 1 mm thick plaques at 220° C. under 5 MT pressure and cooled to room temperature over 10 minutes. A control 1 mm plaque of material without tetrabutylammonium bisulfate is also compression molded under the same conditions. Table 1 shows the optical haze, melting point and modulus of the materials. The reduction in optical haze is 79%, the increase in melting point is 6.0° C. and the retention of modulus is 88%. The optical haze of the material of Example 3 is 17.3%, which represents a retention of 79% relative to the control. Additionally, the material of Example 3 shows a 6.0° C. increase in melting point and a retention of modulus of 88-90% compared to the control.

[0085] Example 4 (Comparative Example): PVDF homopolymer containing 300 ppm of Zonyl 1033D fluorinated amphiphile is mixed with 1.5% tetrabutylammonium bisulfate at 200°C in a twin screw extruder to produce pellets. The pellets are compression molded into 1 mm thick plaques at 220°C under 5 MT pressure and cooled to room temperature over 10 minutes. A control 1 mm plaque of material without tetrabutylammonium bisulfate is also compression molded under the same conditions. Table 1 shows the optical haze, melting point and modulus of the materials. The optical haze of the material of Comparative Example 4 is 20.2%, which represents a retention of 78% relative to the control. However, the melting point increases by less than 1°C and the retention of storage modulus is only 53%, which is much lower than the examples of the present invention.

[0086] [Table 1]

Claims

1. A resin composition comprising: (a) a vinylidene fluoride polymer in which VDF accounts for more than 60% by weight of all monomer units; (b) 0.1 to 3 wt. % of one or more quaternary organic salts, and (c) 10 to 1000 ppm (by weight) of one or more amphipathic dispersants, the amphipathic dispersants not containing fluorine atoms or acid groups. Including, The resin composition, wherein the optical haze of a 1 mm thick section compression molded at 230°C is less than 40% according to ASTM D1003.

2. 10. The resin composition of claim 1, wherein the resin composition has a melting temperature that is at least 2°C higher than the same PVDF resin composition except that it does not contain the quaternary organic salt, and has at least 65% retention of modulus of elasticity compared to the same composition except that it does not contain the quaternary organic salt.

3. The resin composition according to claim 1, wherein the vinylidene fluoride polymer is a homopolymer or a copolymer having at least one comonomer selected from the group consisting of hexafluoropropene, 2,3,3,3-tetrafluoropropylene, and 3,3,3-trifluoropropene.

4. The resin composition according to claim 1 , wherein the vinylidene fluoride polymer is a copolymer containing hexafluoropropylene.

5. 2. The resin composition according to claim 1, comprising a total of 0.2 to 3% by weight of a quaternary organic salt, based on the total weight of (a)+(b)+(c).

6. 2. The resin composition according to claim 1, comprising a total of 10 ppm to 500 ppm of dispersant based on the total weight of (a)+(b)+(c).

7. The resin composition according to claim 1, wherein the optical haze of a 1 mm thick section compression molded at 230°C is less than 35%.

8. 10. The resin composition of claim 1, wherein the melting temperature of the resin composition is at least 3°C higher than the melting temperature of the same composition but without the quaternary organic salt.

9. 10. The resin composition of claim 1, wherein the resin composition has at least 70% modulus retention compared to the same composition but without the quaternary organic salt.

10. The dispersant, a nonionic block copolymer comprising segments of polyethylene glycol, polypropylene glycol and / or polytetramethylene glycol, wherein the number of repeating units per block is 2 to 200; Poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) arranged in an A-B-A triblock structure with 2 to 200 repeating units per block; Alkyl phosphonates, polyvinyl phosphonates, polyvinyl sulfonates, C7 to C20 alkanesulfonates, Alkyl aryl sulfonates, aryl sulfonates, Alkanesulfonates, and combinations of these The resin composition according to claim 1, wherein the resin composition is selected from the group consisting of:

11. The resin composition of claim 1, wherein the dispersant is a block copolymer and comprises at least one block of poly(ethylene glycol) or at least one block of poly(propylene glycol).

12. The resin composition of claim 1, wherein the dispersant comprises a block copolymer having a poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) group or a PEO-PPO-PEO group.

13. The resin composition described in claim 1, wherein the dispersant comprises at least one of sodium lauryl sulfate, sodium laureth sulfate, sodium octyl sulfate, potassium lauryl sulfate, ammonium lauryl sulfate, sodium octyl sulfonate, potassium octyl sulfonate, ammonium octyl sulfonate, and mixtures thereof.

14. The resin composition of claim 1 , wherein the quaternary organic salt is selected from the group consisting of quaternary ammonium salts, quaternary phosphonium salts, and combinations thereof.

15. 2. The composition of claim 1, wherein the quaternary organic salt is selected from the group consisting of tetrabutylammonium bisulfate, heptyltriphenylphosphonium bromide, (2-hydroxyethyl)triphenylphosphonium bromide, (4-carboxybutyl)triphenylphosphonium bromide, and tetrabutylammonium tetrafluoroborate, and combinations thereof.

16. A method for producing the resin composition according to claim 1, comprising the following steps: (a) providing a PVDF polymer; (b) mixing a quaternary organic salt with a dispersant; (c) mixing the blend of step (b) with the PVDF polymer of step (a); Including, The amount of said quaternary organic salt is at least 0.1% by weight and not more than 3% by weight based on the weight of the total dry composition, and the amount of said dispersant in the final composition is from 10 ppm to 1000 ppm (by weight) based on the weight of the total dry composition.

17. A method for producing the resin composition according to claim 1, comprising the following steps: (d) providing a composition having a PVDF polymer and a dispersant in the form of a latex; (e) blending a quaternary organic salt with the latex to form a blend; (f) drying the blend of step (e) to form a solid material. Including, The amount of said quaternary organic salt is at least 0.1% by weight and not more than 3% by weight based on the weight of the total dry composition, and the amount of said dispersant in the final composition is from 10 ppm to 1000 ppm (by weight) based on the weight of the total dry composition.

18. A method for producing the resin composition according to claim 1, comprising the following steps: (g) providing a composition having a PVDF polymer and a dispersant as a latex; (h) drying the latex to form a solid material; (i) blending a quaternary organic salt with the PVDF composition of step (g); Including, The amount of said quaternary organic salt is at least 0.1% by weight and not more than 3% by weight based on the weight of the total dry composition, and the amount of said dispersant in the final composition is from 10 ppm to 1000 ppm (by weight) based on the weight of the total dry composition.

19. 10. An article comprising the resin composition of claim 1, wherein the article can be a film, a sheet, a rod, or a multi-layer part.

20. 20. The article of claim 19, wherein the article is a melt-processed article.