Porous article, method for preparing same, and use thereof

Abstract

The present invention relates to a polymer composition (C) for preparing porous articles, particularly microporous membranes or hollow fibers. More specifically, the present invention relates to a process for preparing a porous article from at least one polyphenylene sulfide (PPS) polymer, an additive, and at least one reinforcing filler, followed by shaping the article and contacting the article with water to dissolve the additive and create an interconnected pore network within the shaped article.

Description

Technical Field

[0001] Related Applications This application claims the benefit of U.S. Provisional Patent Application No. 62 / 898,245, filed Sep. 10, 2019, and European Patent Application Publication No. 19208586.8, filed Nov. 12, 2019, the entire contents of each of which are hereby incorporated by reference for all purposes.

[0002] The present invention relates to polymer compositions for preparing porous articles, particularly microporous membranes or shaped parts. More specifically, the present invention prepares a porous article from at least one polyphenylene sulfide (PPS) polymer, an additive, and at least one reinforcing filler, followed by shaping the article, contacting the article with water to dissolve the additive, and creating a pore network that communicates within the shaped article.

Background Art

[0003] Porous polymer membranes are used in a variety of applications. They can be prepared using a variety of processes.

[0004] The phase inversion method is currently the most commonly used method. Phase inversion means the process of film formation in which a polymer solution is inserted into a semi-solid gel phase by precipitation. In the non-solvent induced phase separation (NIPS) method, a homogeneous polymer solution (also referred to as a "dope solution") containing a polymer, a suitable solvent and / or co-solvent is usually processed into a film by casting and then precipitated by contacting it with a non-solvent medium. In the thermally induced phase separation (TIPS) method, precipitation is obtained by lowering the temperature of the polymer solution. These methods use solvents such as N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), diethyl phthalate (DEP), dibutyl phthalate (DBP) or dioctyl phthalate (DOP). The use of solvents causes serious environmental problems and waste disposal problems. Many active research efforts have been made to replace the use of solvents with environmentally friendly alternatives.

[0005] Another method known as the template leaching technique can be used to prepare porous membranes from polymers that are insoluble in common organic solvents. In this technique, a homogeneous film is prepared from a mixture of a membrane matrix material and a leachable component. The leachable component can be a soluble low molecular weight substance or a macromolecular material such as poly(vinyl alcohol) (PVA) or poly(ethylene glycol) (PEG). After the film is prepared, the leachable component is removed by a suitable chemical treatment, resulting in the formation of a porous structure. One drawback of this method is the low thermal stability of PEG and PVA, which degrade at temperatures above 300 °C.

[0006] U.S. Patent No. 4,196,070 discloses a method for forming a microporous fluorocarbon polymer sheet. This process includes the steps of mixing an aqueous dispersion of polytetrafluoroethylene (PTFE) with a metal organic salt, forming a wet sheet, a concentration step, a drying and sintering step, and a step of leaching out salt crystals.

[0007] U.S. Patent Application Publication No. 2007 / 0232502 relates to a resin porous article and a lubricating oil impregnated in the resin porous article. The resin contains polyethylene, polyether ether ketone (PEEK) and polyamide. The lubricating oil is a perfluoropolyether oil.

[0008] U.S. Patent No. 3,956,020 discloses a method for forming a porous polymer article. This method includes the steps of heating polyethylene, polypropylene or polyolefin, forming a composite by mixing salts, shaping the composite, cooling it to room temperature, forming a solid composite, dissolving the salts, and leaving the polymer as a porous article.

[0009] British Patent No. 920,229 relates to the production of microporous olefin polymers (mainly polyethylene and polypropylene polymers) using water-soluble anionic surfactants.

[0010] International Publication No. 2018 / 065526A1 pamphlet relates to a polymer composition for preparing a porous article. It is a process of preparing a porous article from a blend of at least one semi-crystalline or amorphous polymer and an additive, followed by shaping the article, contacting it with water to dissolve the additive, and creating the article.

[0011] European Patent Application Publication No. 1746125A1 discloses a method for manufacturing a resin porous article. This process includes the steps of adding a pore-forming substance to the resin, shaping, and extracting the pore-forming substance with a solvent that dissolves the pore-forming substance. This document describes blending a polymer and a water-soluble additive either by dry blending or alternatively blending the water-soluble additive in a solvent that dissolves the water-soluble additive, followed by removing the solvent (water) to obtain a moldable composition. The average pore diameter obtained for the porous membrane is 50 - 500 microns.

[0012] Some of the prior art standards using polytetrafluoroethylene (PTFE) have low tensile strength. A further problem with the method is the lack of uniform porosity of the resulting sheet. There are several other methods, such as the use of extractable plasticizers, solvent evaporation, sintering or bonding with adhesives, however, these methods cannot provide the very uniform ultrafine porous structure and ease of control that can be obtained by the present method. Furthermore, when a conventional sliding material containing a lubricating oil is formed into a sliding member, the lubricating oil is generally decomposed.

[0013] There is still a need to provide a porous article made from a polymer, prepared by an environmentally friendly process that does not use solvents such as NMP or DMF and is not accompanied by any radiation source. Another object of the present invention is to provide a concise and cost-effective process for preparing such porous articles. Another object of the present invention is to provide a porous membrane having an average pore size of less than 5 microns (μm), preferably less than 1 micron.

[0014] The method for manufacturing a porous article according to the present invention essentially eliminates all the drawbacks of prior art processes. This process enables the manufacture of strong ultrafine porous articles of solids having a porosity of up to about 60%, and the pore size can be from about 0.01 micron to about 5.0 microns. The porous article is manufactured from at least one polyphenylene sulfide (PPS) polymer that provides an excellent balance of properties such as exceptional mechanical strength, high heat resistance, excellent dimensional stability, inherent flame resistance, good chemical resistance, very high modulus of elasticity and creep resistance, and electrical properties. Furthermore, the porous article of the present invention may include a reinforcing filler that improves the tensile properties and toughens the pores. Summary of the Invention

[0015] An object of the present invention is to provide a polymer composition (C) suitable for preparing a porous polymer article, such as a membrane or hollow fiber.

[0016] According to the present invention, the polymer composition (C) of the present invention contains at least one polyphenylene sulfide (PPS) polymer.

[0017] According to the present invention, the polymer composition (C) of the present invention contains at least 28% by weight of additives based on the total weight of the polymer composition (C).

[0018] According to one embodiment, the polymer composition (C) of the present invention contains at least one reinforcing filler (F).

[0019] Another object of the present invention is to provide a simple and cost-effective process for preparing such porous articles, which process does not use solvents such as NMP or DMF and does not involve an irradiation source.

[0020] According to one embodiment of the present invention, this process includes, for example, a step of processing or shaping a polymer composition into an article by extrusion, and a step of contacting the article with water so as to dissolve one of the components of the polymer composition referred to herein as an "additive", thereby creating a pore network within the shaped article. The inventors have surprisingly found that certain additives that are water-soluble can be homogeneously incorporated in various polymer compositions, particularly semi-crystalline polymer compositions, and withstand severe conditions, i.e., do not deteriorate at high temperatures, especially those used in compounding. Together with the adjusted amount of the additive in the composition, the homogeneous distribution of the additive within the polymer composition provides the possibility of creating a communicating pore network within the shaped article by the step of dissolving it in water.

[0021] According to some embodiments, the porous polymer membrane (M) is used in automotive, 5G telecommunications, and medical / healthcare applications.

Embodiments for Carrying out the Invention

[0022] The present invention relates to a polymer composition (C) comprising at least one polyphenylene sulfide (PPS) polymer, at least 28% by weight of at least one additive based on the total weight of the polymer composition, and at least one reinforcing filler. This composition is used to prepare porous articles, such as microporous membranes or hollow fibers, and is used in a wide range of applications including general filtration (microfiltration and ultrafiltration), the food and dairy industries, wastewater treatment, hemodialysis, battery separators, pre-treatment for reverse osmosis, automotive, 5G telecommunications, and medical / healthcare management. More precisely, a homogeneous article (e.g., a film or membrane) is made from a mixture of a polyphenylene sulfide (PPS) polymer, an additive, and a reinforcing filler. After preparing the shaped article (e.g., a film or membrane), the additive, which is originally water-soluble, is removed from the shaped article by immersing it in water. As a result, a porous structure having a communicating pore network is formed (e.g., a porous film or a porous membrane). By this process, the porous shaped article obtained using such components exhibits not only high porosity but also good mechanical properties and chemical resistance.

[0023] For the sake of clarity, throughout this application, - “Melting temperature (Tm)” or “Tm” or “melting point” means the melting temperature measured by differential scanning calorimetry (DSC) at 20 °C / min according to ASTM D3418, as detailed in the examples, - The term “halogen” includes fluorine, chlorine, bromine, and iodine, unless otherwise specified, - The adjective “aromatic” means any mononuclear or polynuclear ring group (or moiety) having a number of π electrons equal to 4n + 2, where n is 1 or any positive integer, and the aromatic group (or moiety) can be an aryl and an arylene group (or moiety).

[0024] Polyphenylene sulfide (PPS) polymer According to the present invention, the polymer composition (C) of the present invention comprises at least one polyphenylene sulfide (PPS) polymer.

[0025] Polyphenylene sulfide (PPS) is a semi-crystalline, high-temperature engineering thermoplastic. The polyphenylene sulfide (PPS) polymer provides an excellent balance of properties such as exceptional mechanical strength, high heat resistance, excellent dimensional stability, inherent flame resistance, good chemical resistance, very high modulus of elasticity and creep resistance, and electrical properties. It further provides a high modulus of elasticity when reinforced. It is suitable for green initiatives (reusability) compared to conventional materials.

[0026] As used herein, poly(paraphenylene sulfide) (PPS) means any polymer containing at least 50 mol% of the repeating unit (R PPS ).

Chemical formula

[0027] Preferably, at least 60 mol%, 70 mol%, 80 mol%, 90 mol%, 95 mol%, 99 mol%, and most preferably all of the repeating units in PPS are the repeating unit (R PPS ).

[0028] The highly stable chemical bonds in its molecular structure impart significant molecular stability against both thermal degradation and chemical reactivity. This molecular structure also readily forms a highly thermally stable crystal lattice, and thus, PPS is a semi-crystalline polymer with a high crystal melting point of 285 o °C.

[0029] Generally, the polyphenylene sulfide (PPS) polymer in the polymer composition can have a weight average molecular weight (Mw) in the range of 10,000 g / mol to 150,000 g / mol, preferably 20,000 g / mol to 100,000 g / mol or 40,000 g / mol to 95,000 g / mol. The weight average molecular weight can be determined by gel permeation chromatography using ASTM D5296 with polystyrene standards.

[0030] PPS is manufactured and sold by Solvay Specialty Polymers USA, LLC under the trademark name Ryton® PPS. Excellent results were obtained when the polymer used to prepare the porous membrane was PPS.

[0031] Additive The polymer composition (C) of the present invention has the formula (I): R a -Ar-X b (I) (wherein, - Ar is an aromatic moiety and is selected from the group consisting of substituted or unsubstituted aromatic monocyclic or polycyclic groups having 5 to 18 carbon atoms, - Each of R's is the same as or different from each other and is selected from the group consisting of halogen, hydroxyl, C1-C18 aliphatic group, C1-C18 alicyclic group and C1-C18 aromatic, - a is an integer in the range of zero or 1 to 5, preferably, a is zero or 1, - X is (COO - ) 、 (M p+ ) 1 / p (wherein M p+ is a p-valent metal cation), - b is an integer in the range of 1 to 4, preferably, b is 1 or 2) also includes an additive of.

[0032] One of the essential features of the present invention is the use of an additive in the form of a salt of a carboxylic acid, more precisely a carboxylate -COO - The additive may contain 1 to 4 groups X that are the same as or different from each other, where X is (COO - ) 、 (M p+ ) 1 / p (wherein M p+ is a p-valent metal cation).

[0033] According to one embodiment, each R of the additive of formula (I) is the same as or different from each other and is selected from the group consisting of halogen, hydroxyl, and C1-C3 aliphatic groups (i.e., methyl, ethyl, or propyl).

[0034] According to one embodiment, M is selected from the group consisting of sodium, potassium, calcium, lithium, magnesium, silver, aluminum, zinc, nickel, copper, palladium, iron, and cesium. Preferably, M is sodium or potassium.

[0035] Alternatively, M can be specifically selected from among alkali metals (Group IA of the periodic table) or alkaline earth metals (Group IIA of the periodic table).

[0036] According to one embodiment, X is a sodium salt and / or a potassium salt of a carboxylic acid.

[0037] The additive used in the present invention can be inherently water-soluble.

[0038] The additive can be said to be extractable as defined below.

[0039] According to one embodiment of the present invention, the aromatic moiety of formula (I) is

Chemical formula

[0040] According to one embodiment of the present invention, the additive of formula (I) is such that each aromatic moiety of formula (I), for example, (Ar-A) to (Ar-D), contains 1, 2, or 3 groups X that are the same as or different from each other, where X is (COO- ) 、 (M p+ ) 1 / p (wherein M p+ is a p-valent metal cation).

[0041] According to one embodiment of the present invention, the additive of formula (I) is such that each aromatic moiety of formula (I) contains 1 or 2 groups X that are the same or different, where X is (COO - ) 、 (M p+ ) 1 / p (wherein M p+ is a p-valent metal cation).

[0042] According to one embodiment, the additive is of formula (II): [Chemical formula] (wherein - Each of -R is the same as or different from each other and is selected from the group consisting of halogen, hydroxyl, C1-C18 aliphatic group, C1-C18 alicyclic group, and C1-C18 aromatic group, - a is an integer in the range of zero or 1 to 5, - X is (COO - ) 、 (M p+ ) 1 / p (wherein M p+ is a p-valent metal cation), - b is either 1 or 2) is according to).

[0043] According to a further embodiment of the present invention, the additive of formula (I) or (II) is an additive wherein a is 0, 1, or 2.

[0044] According to another embodiment, since a is zero, the phenylene moiety has no substituents other than sulfonate or carboxylate functional groups.

[0045] According to another embodiment of the present invention, the additive salt is an alkyl or aryl benzoate, methyl benzoate, ethyl benzoate, propyl benzoate, and butyl benzoate.

[0046] According to another embodiment of the present invention, the additive is selected from the group consisting of sodium, or potassium alkyl, or aryl benzoate, sodium or potassium methyl benzoate, sodium or potassium ethyl benzoate, sodium or potassium propyl benzoate, and sodium or potassium butyl benzoate.

[0047] The additive is present in the composition of the present invention in an amount of at least 28% by weight based on the total weight of the composition.

[0048] According to another embodiment of the present invention, the composition contains about 28 to about 80% by weight, for example about 30 to about 75% by weight or about 35 to about 70% by weight of the additive.

[0049] According to one embodiment of the present invention, the additive has a melting temperature Tma (°C) of at least 150 °C, for example at least 170 °C, at least 180 °C, at least 190 °C, or at least 200 °C, as measured by differential scanning calorimetry (DSC) according to ASTM D3418.

[0050] According to an embodiment of the present invention, the polymer composition (C) is - at least one polyphenylene sulfide (PPS) polymer, and - at least 28% by weight of the polymer composition (C), for example at least one of the above-mentioned additives selected from the group consisting of sodium or potassium benzoate, sodium or potassium methyl benzoate, sodium or potassium ethyl benzoate, sodium or potassium propyl benzoate, and sodium or potassium butyl benzoate, preferably sodium or potassium benzoate, and - at least one reinforcing filler and comprises.

[0051] Reinforcing filler The polymer composition optionally contains at least one reinforcing filler such as a fibrous or particulate filler. The fibrous reinforcing filler is a material having a length, width, and thickness where the average length is considerably larger than both the width and thickness. Preferably, such a material has an aspect ratio defined as the average ratio between the length and the least of the width and thickness of at least 5. Preferably, the aspect ratio of the reinforcing fiber is at least 10, more preferably at least 20, even more preferably at least 50. The particulate filler has an aspect ratio of at most 5, preferably at most 2.

[0052] Preferably, the reinforcing filler is selected from mineral fillers such as talc, mica, kaolin, calcium carbonate, calcium silicate, magnesium carbonate, boron nitride; glass fibers, carbon fibers, boron carbide fibers; wollastonite; silicon carbide fibers, boron fibers, graphene, carbon nanotubes (CNT), basalt fibers and the like. Most preferably, the reinforcing filler is glass fiber, preferably chopped glass fiber or carbon fiber, preferably chopped carbon fiber.

[0053] Glass fiber is a silica-based glass compound containing several metal oxides that can be adjusted to yield different types of glass. The main oxide is silica in the form of quartz sand, and other oxides such as calcium, sodium, and aluminum are incorporated to lower the melting temperature and prevent crystallization. Glass fibers have a circular cross-section or a non-circular cross-section (so-called "flat glass fibers") including oval, elliptical, or rectangular. Glass fibers can be added as continuous fibers or chopped glass fibers. Glass fibers generally have an equivalent diameter of 5 to 20, preferably 5 to 15 μm, more preferably 5 to 10 μm. All glass fiber types such as A, C, D, E, M, S, R, T glass fibers (as described in Chapter 5.2.3, pages 43 - 48 of Additives for Plastics Handbook, 2nd ed, John Murphy, which is incorporated herein by reference) or any mixtures thereof can be used. For example, R, S, and T glass fibers are typically high-modulus glass fibers having a modulus of elasticity of at least 76, preferably at least 78, more preferably at least 80, and most preferably at least 82 GPa as measured according to ASTM D2343.

[0054] E, R, S, and T glass fibers are well-known in the art. They are described, inter alia, in Chapter 5, pages 197 - 225 of Fiberglass and Glass Technology, Wallenberger, Frederick T.; Bingham, Paul A. (Eds.), 2010, XIV, which is incorporated herein by reference. R, S, and T glass fibers consist essentially of oxides of silicon, aluminum, and magnesium. In particular, those glass fibers typically contain 62 - 75 wt% SiO2, 16 - 28 wt% Al2O3, and 5 - 14 wt% MgO. Unlike the ordinary E-glass fibers widely used in polymer compositions, R, S, and T glass fibers contain less than 10 wt% CaO.

[0055] Fibrous fillers, especially glass fibers, can have a cross-sectional longest diameter of at least 15 μm, preferably at least 20 μm, more preferably at least 22 μm, and even more preferably at least 25 μm. Advantageously, it is at most 40 μm, preferably at most 35 μm, more preferably at most 32 μm, and even more preferably at most 30 μm. Excellent results were obtained when the cross-sectional longest diameter was in the range of 15 to 35 μm, preferably 20 to 30 μm, and more preferably 25 to 29 μm.

[0056] Fibrous fillers, especially glass fibers, can have a cross-sectional shortest diameter of at least 4 μm, preferably at least 5 μm, more preferably at least 6 μm, and even more preferably at least 7 μm. Advantageously, it is at most 25 μm, preferably at most 20 μm, more preferably at most 17 μm, and even more preferably at most 15 μm. Excellent results were obtained when the cross-sectional shortest diameter was in the range of 5 to 20 μm, preferably 5 to 15 μm, and more preferably 7 to 11 μm.

[0057] Fibrous fillers, especially glass fibers, can have an aspect ratio of at least 2, preferably at least 2.2, more preferably at least 2.4, and even more preferably at least 3. The aspect ratio is defined as the ratio of the longest diameter to the shortest diameter in the cross-section of the glass fiber. Also, the aspect ratio of the glass fiber is at most 8, preferably at most 6, and more preferably at most 4. Excellent results were obtained when the ratio was about 2 to about 6, preferably about 2.2 to about 4.

[0058] The shape of the cross-section of the glass fiber, its length, its cross-sectional diameter, and its aspect ratio can be easily determined using optical microscopy.

[0059] The amount of the reinforcing filler, based on the total weight of the polymer composition, is 1 wt% to 40 wt%, preferably 5 wt% to 35 wt%, most preferably 10 wt% to 30 wt% in the case of particulate fillers, and 1 wt% to 50 wt%, preferably 2 wt% to 30 wt%, most preferably 3 wt% to 20 wt% in the case of fibrous fillers. Preferably, the polymer composition comprises about 10 wt% to about 20 wt%, most preferably about 15 wt% of glass fiber or carbon fiber, most preferably glass fiber. In some embodiments, the polymer composition comprises less than 10 wt%, less than 5 wt%, less than 1 wt% of fibrous filler, particulate filler, or both. In some aspects, the polymer composition does not contain fibrous filler, particulate filler, or both.

[0060] Basalt fiber is a material made from extremely fine fibers of basalt, which is composed of the minerals plagioclase, pyroxene, and cancrinite. They are similar to glass fibers but have better physical and mechanical properties than glass fibers and are considerably less expensive than carbon fibers.

[0061] Any component In some embodiments, the polymer composition (C) contains titanium dioxide (TiO2). The amount of titanium dioxide is preferably in the range of 0 pph to about 25 pph, such as about 0.1 pph to about 25 pph, such as about 5 pph to about 20 pph. The amount of titanium dioxide (TiO2) can be up to about 25 pph, preferably up to about 20 pph, preferably up to about 20 pph, preferably up to about 15 pph.

[0062] The polymer composition (C) may further optionally contain additional components such as ultraviolet stabilizers, heat stabilizers, antioxidants, pigments, processing aids, lubricants, flame retardants, plasticizers, and / or conductive additives such as carbon black and carbon nanofibers.

[0063] The polymer composition (C) may further comprise a water-soluble or dispersible polymer additive for the benefit of processing and / or optimizing the pore morphology and / or porosity. Examples of such polymers include sulfo-polyesters, polyvinyl alcohol, polyethylene oxide, polyethylene oxide / propylene oxide copolymers, polyethyleneimine, polyethyloxazoline, and polyvinylpyrrolidone. Such polymer additives are selected to maintain a stable state at the desired processing temperature and to allow substantial extraction with water from the final product.

[0064] The polymer composition (C) may further comprise a flame retardant, such as halogenated and halogen-free flame retardants.

[0065] Article (A) and uses comprising the polymer composition (C) The polymer composition (C) described herein can be used to produce a variety of molded articles. In the context of the present invention, the term "article" is thus to be understood in a broad sense. The term refers to any kind of product that can be formed from a polymeric material and includes (a) an intermediate product (or intermediate shaped article) that is non-porous and that results directly from a process that includes shaping the polymer composition of the present invention into a shaped article, for example, by injection molding, extrusion molding, or 3D printing, and (b) a final product (or final shaped article) that is porous and that is obtained from an intermediate product by, for example, immersion in water to dissolve additives and create pores. In this context, the additives are said to be water-soluble and / or extractable.

[0066] The polymer composition (C) can be used for heat insulating or sound insulating materials of variable shape and size.

[0067] The polymeric article (A) comprising the polymer composition (C) of the present invention can be used as a filter medium or membrane (e.g., microfiltration or ultrafiltration).

[0068] The article is preferably a membrane. The polymer compositions described herein are in fact very suitable for producing this type of membrane. The term "membrane" is used herein in its ordinary meaning, i.e., a membrane means an individual, usually thin interface that moderates the penetration of chemical species in contact with the membrane. This interface can be molecularly uniform (i.e., the structure can be completely uniform (dense membrane)) or chemically or physically non-uniform, for example, it can contain void pores or pores of finite dimensions (porous membrane). The membrane can be in the form of a flat sheet or a tubular form. Tubular membranes are classified based on their dimensions in tubular membranes having a diameter greater than 3 mm, capillary membranes having a diameter included in the range of 0.5 mm to 3 mm, and hollow microfibers having a diameter less than 0.5 mm. When high flux is required, flat sheet membranes are generally preferred, but hollow fibers are particularly advantageous in applications where a compact module with a large surface area is required.

[0069] Porous membranes can be characterized by their pore diameters. In some embodiments, the average pore diameter of the porous polymer membrane ranges from about 0.01 micron (μm) to about 5.0 microns, preferably from about 0.02 micron to about 2.0 microns, most preferably from about 0.05 micron to about 1.0 micron, and even more preferably from about 0.07 micron to about 0.5 micron.

[0070] Porous membranes can be characterized by permeability measurement (the volume of water permeating through the membrane under given pressure conditions), porosity (the ratio of the volume of voids to the total volume occupied by the membrane), and pore characteristics (average pore diameter, minimum pore diameter, and maximum pore diameter). Porous membranes can similarly be characterized by their mechanical properties (especially tensile properties) and chemical resistance (during a given time in various solvents after immersion).

[0071] The article can be used alone or in a bundle arrangement and configuration, for example, in a filtration system. The article can be, for example, a microfiltration membrane, an ultrafiltration membrane, or a support for reverse osmosis.

[0072] These articles can be used for the separation of various materials. The potential usefulness of such membrane articles varies depending on the membrane material, its structure (which varies depending on the preparation method), and the mode of operation. For example, such articles can permeate gases, such as oxygen or nitrogen, separate solutes of suspensions from solutions, such as separating soluble waste from blood (hemodialysis), or separate dissolved molecules, colloids, and suspended solids from smaller molecules (ultrafiltration), for example, in the production of latex or cheese.

[0073] The inventors have shown that the porous membrane of the present invention exhibits an improved porous structure.

[0074] Accordingly, the present invention also relates to a method of using a final shaped article, such as a porous membrane, in filtration and purification processes, such as wastewater filtration, in the preparation of ultrapure water, and in medical, pharmaceutical, or food applications including microbial removal, dialysis, and protein filtration.

[0075] That is, the present invention relates to the use of shaped articles for filtering or purifying liquids, such as wastewater filtration, for preparing ultrapure water, and in medical, pharmaceutical, or food applications including microbial removal, dialysis, and protein filtration.

[0076] The porosity of the membrane can range from 3 to 90%, preferably from 5 to 80% or from 20 to 70%. For example, the membrane has a porosity of about 50% or about 60%.

[0077] The pores can have an average diameter of at least 0.001 μm, at least 0.005 μm, at least 0.01 μm, at least 0.1 μm, at least 1 μm, at least 10 μm, and up to 50 μm.

[0078] According to one embodiment, a porous polymer article, such as a membrane, is used in an automobile.

[0079] According to another embodiment, a porous polymer article, such as a membrane, is used in 5G telecommunications.

[0080] According to another embodiment, a porous polymer article, such as a membrane, is used in medical / healthcare applications.

[0081] According to another embodiment, a porous polymer article, such as the porous membrane according to the present invention, can be used to filter biological solutions (e.g., biofilms, viruses, other large molecules) and / or buffers (e.g., solutions that may contain small amounts of solvents such as DMSO or other polar aprotic solvents).

[0082] According to another embodiment of the present invention, the polymer composition (C) is used as a support material in a process for manufacturing three-dimensional objects using an extrusion-based additive manufacturing system, also known as the fused deposition modeling process. The polymer composition (C) used as a support material in these 3D manufacturing methods is provided in the form of a filament. The filament can have a cylindrical shape or a substantially cylindrical shape, or a non-cylindrical shape such as a ribbon filament shape. Furthermore, the filament can have a hollow shape or a core-shell shape, and the support material of the present invention is used to form either the core or the shell.

[0083] Method for manufacturing the polymer composition (C), article (A) and porous article The present invention also relates to a method for manufacturing the above-described polymer composition (C), the method including a step of melt-mixing at least a polyphenylene sulfide (PPS) polymer, an additive, and a reinforcing filler.

[0084] More precisely, the polymer composition (C) comprises at least one polyphenylene sulfide (PPS) polymer in an amount of at least 28% by weight based on the total weight of the polymer composition (C) of the formula (I): R a -Ar-X b (I) (wherein, - Ar is an aromatic moiety and is selected from the group consisting of substituted or unsubstituted aromatic monocyclic or polycyclic groups having 5 to 18 carbon atoms, - Each of R's is the same as or different from one another and is selected from the group consisting of halogen, hydroxyl, C1-C18 aliphatic group, C1-C18 alicyclic group, and C1-C18 aromatic, - a is an integer in the range of zero or 1 to 5, - X is (COO - ) 、 (M p+ ) 1 / p (wherein M p+ is a p-valent metal cation), - b is an integer in the range of 1 to 4) can be produced by melt-mixing at least one additive of and optionally at least one reinforcing filler to provide a melt mixture.

[0085] The polymer composition (C) described herein is preferably provided in the form of pellets. These pellets can be used in injection molding or extrusion processes known in the art.

[0086] The polymer composition (C) can be prepared by methods known to those skilled in the art. For example, such methods include melt mixing processes. In some preferred embodiments, the preparation process of the polymer composition includes melt mixing at least one polymer (P) with at least 28% by weight of at least one additive of formula (I). The melt mixing process is typically carried out by heating a thermoplastic polymer together with additive (I) above the melting temperature (Tm) of the thermoplastic polymer (P), thereby forming a melt of the blend. It is advantageous to have a melt compounding that results in pellets together with the polymer, additive and optionally a reinforcing filler. Such a process can be carried out by heating the polymer (P) above the melting temperature (Tm) of the semi-crystalline polymer and / or above the glass transition temperature (Tg) of the amorphous polymer to form a melt of the polymer / additive (I) blend. In some embodiments, the processing temperature ranges from about 180 to 450 °C, preferably from about 220 to 440 °C, about 260 to 430 °C or about 280 to 420 °C. The processing temperature is preferably at least 15 °C, preferably at least 30 °C, at least 50 °C, at least 80 °C or at least 100 °C higher than the melting temperature (Tm) of the semi-crystalline polymer (or, if the composition contains several semi-crystalline polymers, the polymer with the highest Tm in the polymer composition). The processing temperature is preferably at least 15 °C, preferably at least 30 °C or at least 50 °C higher than the glass transition temperature (Tg) of the amorphous polymer (or, if the composition contains several amorphous polymers, the polymer with the highest Tg in the polymer composition). In the case of a blend of an amorphous polymer and a semi-crystalline polymer, the melt mixing process is carried out at the highest temperature of Tm or Tg.

[0087] In some preferred embodiments, the melt blending comprises heating a semi-crystalline polymer (P) together with an additive (I) above its melting temperature (Tm) to form a melt of the polymer / additive blend. Even more preferably, the processing temperature is at least 15 °C, preferably at least 20 °C, at least 30 °C, at least 40 °C or at least 50 °C higher than the melting temperature (Tm) of the semi-crystalline polymer.

[0088] The additive used in connection with the present invention is preferably in powder form.

[0089] The process for preparing the composition can be carried out in a melt blending apparatus, and for this purpose any melt blending apparatus known to those skilled in the art for preparing a polymer composition by melt blending can be used. Suitable melt blending apparatuses are, for example, kneaders, Banbury mixers, single-screw extruders and twin-screw extruders. Preferably, an extruder equipped with means for introducing all of the desired components either into the feed port of the extruder or into the melt is used. In the process for preparing the polymer composition, the components forming the composition are fed to the melt blending apparatus and melt blended therein. The components can be fed simultaneously as a powder mixture, also known as a dry blend, or as a granule mixer or individually.

[0090] The order of combining the components during the melt blending is not particularly limited. In one embodiment, the components can be mixed in a single batch, so that the respective desired amounts of the components can be added together and subsequently mixed. In other embodiments, a first subset of the components can be mixed together first, and one or more of the remaining components can be added to the mixture for further mixing. For clarity, it is not necessary for the total desired amount of each component to be mixed as a single amount. For example, in one or more of the components, some of the amount can be added first, mixed, and subsequently some or all of the remainder can be added and mixed.

[0091] The method for producing the polymer composition (C) may include several consecutive steps of melt mixing or extrusion molding under different conditions, if necessary.

[0092] Each step of the method itself or, when relevant, may further include a step of cooling the melt mixture.

[0093] The intermediate non-porous article (e.g., shaped non-porous membrane or shaped porous film) and the final porous article according to the present invention (e.g., porous membrane or porous film) are made from the polymer composition (C) using any suitable dissolution treatment method. Specifically, they are made by injection molding, extrusion molding, or 3D printing.

[0094] For this purpose, any standard molding technique can be used, and standard techniques including shaping the polymer composition in a molten / softened form can be advantageously applied, which include, among others, compression molding, extrusion molding, injection molding, transfer molding, etc. The article can be shaped using a die, and for example, when the article is a hollow fiber membrane, the die has an annular orifice.

[0095] According to one embodiment of the present invention, the method for forming a polymer article (intermediate non-porous or final porous) includes a step of printing a layer of a three-dimensional object from the provided polymer composition (C). According to this embodiment, the polymer article is actually formed using an additive manufacturing system of an extrusion molding type, also known as a fused deposition modeling method.

[0096] According to one embodiment of the present invention, the method for forming a polymer article (intermediate non-porous article or final porous article) includes at least a step of extruding the above-described polymer composition (C).

[0097] According to one embodiment of the present invention, a method of forming a porous polymer article (e.g., a porous membrane or a porous hollow fiber) additionally includes a step of immersing an intermediate non-porous article in, for example, water or a solution containing water to bring it into contact with water. The water used to dissolve the water-soluble additive can be, for example, various temperatures from room temperature to 95°C. The time required to dissolve the polymer varies. By way of example, the time can vary from 1 second to 2 hours or from 5 seconds to 1 hour.

[0098] According to this embodiment, the additive can be said to be extractable, that is, it can be substantially extracted from the intermediate product by contacting with water, for example, by immersing it in water, and the water can be heated to 95°C over a period of up to 2 hours in some cases. In this context, "substantially" means that at least 80% by weight, for example, at least 85% by weight, at least 90% by weight or at least 95% by weight of the additive is extracted from the intermediate product in order to obtain the final porous shaped article.

[0099] Accordingly, the present invention also relates to a method of forming a porous polymer membrane M), the method comprising (i) a step of preparing the above-described polymer composition (C); (ii) a step of processing the polymer composition (C) into a membrane, for example, extruding the polymer composition (C) into a flat membrane; (iii) a step of immersing the membrane in water and including.

[0100] The method of forming the porous polymer membrane (M) can include one or several optional steps. One optional step includes a step of stretching the membrane. This optional step can be particularly carried out during step (iii). Another optional step includes drying the membrane, for example, in an oven.

[0101] The present invention also relates to a porous polymer article (e.g., a membrane or a hollow tube) obtained by this method.

[0102] The porous polymer article may contain up to 20 wt% of additives, such as up to 15 wt% of additives, up to 10 wt% of additives, up to 5 wt% of additives, or less than 5 wt% of additives. According to one embodiment, the porous polymer article contains less than 1 wt% of additives.

[0103] An injection molded part having a fiber reinforcement provides significantly better mechanical strength (tensile strength, specific tensile strength) and modulus of elasticity (specific modulus of elasticity) than its porous non-reinforced equivalent. Adding glass fibers can proportionally increase other internal properties such as the dielectric constant and the dielectric loss factor.

[0104] The polymer composition (C) can generally be processed, without departing from the scope of the present invention, by injection molding it, if necessary, into an injection molded article to obtain a part having the required final shape.

[0105] The present invention relates to an article suitable for use in the oil / gas recovery industry, comprising at least one structural part produced by injection molding a polyphenylene sulfide (PPS) polymer composition (C), wherein the injection molded structural part of the polyphenylene sulfide (PPS) polymer composition (C) is characterized by improved mechanical properties, in particular high rigidity and high toughness, increased breakdown voltage, dimensional stability and good aesthetic properties.

[0106] The article according to the present invention can be coated or further processed.

[0107] Therefore, the method as detailed above may further include at least one additional step, including coating at least a portion of the surface of the part with at least one metal.

[0108] In case the disclosure of any patent, patent application and publication incorporated herein by reference conflicts with the description of this application to the extent that it may obscure the terms, the description shall prevail.

[0109] The present invention will be illustrated in more detail in the following sections by non-limiting examples below.

Example

[0110] Four examples and two corresponding comparative examples are provided.

[0111] Raw materials 1) PPS polymer: Ryton® QC160N from Solvay Specialty Polymers USA, LLC. 2) Sodium benzoate, product name of Fluid Energy, Telford, PA: micronized sodium benzoate (NaBz). 3) Glass fiber, T-779H from Nippon Electric Glass, Otsu, Japan.

[0112] Example 1 By blending the components in a Coperion ZSK-26 twin-screw extruder (Coperion GmbH, Stuttgart, Germany), a mixture of 42.75 weight percent (wt%) of Ryton® QC-160, 55 wt% of sodium benzoate, and 2.25 wt% of glass fiber (T-779H, Nippon Electric Glass, Otsu, Japan) was produced. This extruder had 12 barrel regions and a heated outlet die operating up to 450 o °C, enabling a mass throughput > 30 kg / hour. A side feeder was used on the Coperion ZSK-26 to introduce the glass fiber into barrel 7. When the actual melt temperature at the outlet die was measured with a hand-held instrument, it was found to be 375 o °C. ISO bars were manufactured and property tests were carried out. The data of these tests are shown in Tables 1 - 4. After extraction, this sample had a glass fiber content of 5 wt%.

[0113] Example 2 A mixture of 40.5 weight percent (wt%) of Ryton® QC-160N, 55 wt% of sodium benzoate, and 4.5 wt% of glass fiber (ECS03T-T779, Nippon Electric Glass, Otsu, Japan) was manufactured as described in Example 1. When the actual melting temperature at the exit die was measured with a handheld device, it was found to be 375 o °C. ISO bars were manufactured as described in Example 1 and property tests were conducted. The data from these tests are shown in Tables 1 - 4. After extraction, this sample had a glass fiber content of 10 wt%.

[0114] Example 3 A mixture of 38.25 weight percent (wt%) of Ryton® QC-160N, 55 wt% of sodium benzoate, and 6.75 wt% of glass fiber (ECS03T-T779, Nippon Electric Glass, Otsu, Japan) was manufactured as described in Example 1. When the actual melting temperature at the exit die was measured with a handheld device, it was found to be 410 o °C. ISO bars were manufactured as described in Example 1 and property tests were conducted. The data from these tests are shown in Tables 1 - 4. After extraction, this sample had a glass fiber content of 15 wt%.

[0115] Example 4 A mixture of 36 weight percent (wt%) of Ryton® QC-160N, 55 wt% of sodium benzoate, and 9 wt% of glass fiber (ECS03T-T779, Nippon Electric Glass, Otsu, Japan) was manufactured as described in Example 1. When the actual melting temperature at the exit die was measured with a handheld device, it was found to be 400 o °C. ISO bars were manufactured as described in Example 1 and property tests were conducted. The data from these tests are shown in Tables 1 - 4. After extraction, this sample had a glass fiber content of 20 wt%.

[0116] To obtain the appropriate mass ratios of the components, each material was fed into the feed section of the extruder using a K-Tron T-35 gravimetric feeder (from Coperion GmbH, Stuttgart, Germany). The components were melted and mixed with a screw designed to obtain a uniform melt composition. When the actual melt temperature at the exit die was measured with a handheld device, it was found to be 385 o °C.

[0117] The melt stream was air-cooled and fed into a Maag Primo 60E pelletizer (from Maag Automatik GmbH, Stuttgart, Germany). The typical production rate was 10 - 20 kg per hour. The pellets were recovered and stored in a sealed plastic bucket until used for injection molding. ISO bars were manufactured by injection molding and tested according to ISO 527-2. Before testing, the soluble components were extracted using hot water (80 - 95 o °C) for 24 hours and dried in a vacuum oven at 100 o °C and <20 inches Hg. The dimensional losses were measured at the neck width and thickness of the ISO bars and were found to be 1.0% and 2.5% respectively. For these samples, the percentage of porosity (%) was calculated by gravimetry. The results are shown in Table 1.

[0118] The mercury intrusion test was performed by the Particle Testing Authority (Norcross, GA). The data for porosity, bulk density and pore diameter, Dp (pore diameter at the maximum incremental mercury intrusion) are shown in Table 1.

[0119]

Table 1

[0120] Tensile tests were performed as described above, and the tensile strength and modulus of elasticity are shown in Table 2. The specific tensile strength and modulus of elasticity were calculated using the bulk density and are shown in Table 2.

[0121]

Table 2

[0122] The dielectric constant and dielectric tangent were measured at 2.4 GHz using the guidelines of ASTM D2520, Method B - Resonant Cavity Perturbation Technique by Electronics Consulting Laboratories (Red Lion, PA). The dielectric constant and dielectric tangent were measured on porous films, and these porous films are used for 5G applications. The presence of voids containing air with lower dielectric constant and dielectric loss results in an organized value of the dielectric properties of the composite of air and plastic in the insulating gap between the two electrodes. Therefore, lower dielectric properties (Dk, Df) of the porous material are obtained compared to the solid material. The dielectric properties are shown in Table 3.

[0123]

Table 3

[0124] The measurement of the thermal conductivity (K) was carried out on a hot disk (registered trademark) (Gothenburg, SE) at 23 o °C using a Kapton sensor. The thermal conductivity, K data of these samples are shown in Table 4.

[0125]

Table 4

[0126] Comparative Example 1 To produce a mixture of 40 weight percent (wt%) Ryton® PPS, QC-160N and 60 wt% sodium benzoate (manufactured by Fluid Energy, Telford, PA, product name: Micronized Sodium Benzoate), the components were blended in a Coperion ZSK-26 twin screw extruder (Coperion GmbH, Stuttgart, Germany). This extruder had 12 barrel zones and a heated exit die that operated up to 450 o °C and enabled a mass throughput > 30 kg / hour. The barrel profile shown below was used.

[0127]

Table 5

[0128] Comparative Example 1 does not use glass fiber. The porosity by weight measurement, porosity (Hg intrusion), bulk density, and pore diameter are shown in Table C1. When no glass fiber was used, in Comparative Example 1, the bulk density was lower and the pore diameter was larger, indicating that a fine pore structure was achieved when glass fiber was used.

[0129]

Table 6

[0130] The elastic modulus, specific elastic modulus, tensile strength, and specific tensile strength are shown in Table C2. When no glass fiber was used, in Comparative Example 1, the elastic modulus, specific elastic modulus, tensile strength, and specific tensile strength were lower.

[0131]

Table 7

[0132] The dielectric constant, dielectric loss factor, and thermal conductivity are shown in Table C3. When no glass fiber was used, in Comparative Example 1, the dielectric constant, dielectric loss factor, and thermal conductivity were lower.

[0133]

Table 8

[0134] Comparative Example 2 A mixture of 45% by weight of Radilon® S24E polyamide 6 and 55% by weight of sodium benzoate was prepared as described in Comparative Example 1. The following barrel profile was used.

[0135]

Table 9

[0136] When the actual melt temperature at the exit die was measured with a hand-held device, it was found to be 250 o °C. ISO bars were manufactured and extraction in hot water was carried out as described in Example 1. During extraction, the samples shrank considerably. The dimensional losses were measured at the neck width and thickness of the ISO bars and were found to be 19% and 29% respectively. Mercury was carried out as described in Example 1 and the data for these tests are shown in Table C4. The dimensional losses indicate that the samples lost porosity due to shrinkage, even though the weight measurement-based estimate of porosity was high. This is supported by mercury intrusion data showing a shift to a bimodal size distribution of lower porosity and higher density, as well as pore size Dp, for other examples of this operation. The lower values probably indicate collapsed pores. The larger values may be due to shrinkage-induced defects such as delamination of the skin layer on the bar surface from the bulk of the sample.

[0137]

Table 10

[0138] Furthermore, the method for manufacturing the above article includes machining of injection-molded standard shaped structural parts within parts having any type of size and shape. Non-limiting examples of the standard shaped structural parts include, in particular, plates, rods, slabs, sheets, films, and the like. The standard shaped structural parts are obtained by injection molding of the polymer composition (C).

Claims

1. A method for forming a porous polymer membrane (M), comprising: (i) - at least one polyphenylene sulfide (PPS); - at least 28% by weight, based on the total weight of the polymer composition (C), of a compound of formula (I): R ａ -Ar-X ｂ (I) (wherein - Ar is an aromatic moiety and is selected from the group consisting of substituted or unsubstituted aromatic monocyclic or polycyclic groups having 5 to 18 carbon atoms; - each of R's is the same as or different from each other and is selected from the group consisting of halogen, hydroxyl, C1-C18 aliphatic group, C1-C18 alicyclic group and C1-C18 aromatic group; - a is zero or an integer in the range of 1 to 5; - X is (COO － )( 、 (M ｐ＋ )( １／ｐ (wherein M ｐ＋ is a p-valent metal cation) and - b is an integer in the range of 1 to 4) of at least one additive; - at least one reinforcing filler to prepare a polymer composition (C); (ii) a step of processing the polymer composition (C) into a film; (iii) a step of immersing the film in water The method comprising.

2. The method according to claim 1, wherein step (i) comprises melt mixing at least one polyphenylene sulfide (PPS) with at least 28% by weight of the at least one additive of formula (I).

3. The method according to claim 2, wherein the melt mixing comprises heating the polyphenylene sulfide (PPS) together with the additive of formula (I) to a processing temperature (Tp) above the melting temperature (Tm) of the polymer to form a melt.

4. The method according to claim 3, wherein the processing temperature (Tp) is at least 15 °C higher than the melting temperature (Tm) of the polyphenylene sulfide (PPS).

5. Ar in formula (I) is 【Chemical 1】 (wherein Z is a divalent moiety and is selected from the group consisting of —SO ２ —, —CO— and alkylene having 1 to 6 carbon atoms) selected from the group consisting of The method according to any one of claims 1 to 4.

6. [Chemical Formula 2] The additive is of formula (II): (wherein - each of R's is the same as or different from each other and is selected from the group consisting of halogen, hydroxyl, C1-C18 aliphatic group, C1-C18 alicyclic group and C1-C18 aromatic group; - X is (COO － ), 、 (M ｐ＋ ), １／ｐ (where M ｐ＋ is a p-valent metal cation), and - a is zero or an integer in the range of 1 to 5; - b is either 1 or 2)

7. The method according to any one of claims 1 to 6, wherein the additive salt is selected from the group consisting of benzoate, methyl benzoate, ethyl benzoate, propyl benzoate and butyl benzoate.

8. The method according to any one of claims 1 to 7, comprising 30% to 70% by weight of said additive. **Claim 9** The method according to any one of claims 1 to 8, wherein the reinforcing filler is a fibrous filler, and the polymer composition comprises the fibrous filler in an amount in the range of 5% to 50% by weight based on the total weight of the polymer composition. **Claim 10** The method according to any one of claims 1 to 9, wherein the reinforcing filler is selected from the group consisting of glass fiber, carbon fiber, and basalt fiber.

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