Oil-water separation filter and method for manufacturing the same

Abstract

The present invention provides an oil-water separation filter, which is an oil-water separation filter comprising a non-woven fabric having a plurality of pores formed between fibers, wherein the plurality of pores penetrate between a side into which a liquid containing water and oil flows and another side opposite to the side from which the liquid flows out. A water-repellent and oil-repellent membrane is formed comprising oxide particles (B) having an average particle size of 2 to 90 nm and a carboxyl-containing substance (C), wherein the oxide particles (B) having an average particle size of 2 to 90 nm are particles having a fluorine-based functional group component (A) having a perfluoroether structure of formula (1) bonded to the fiber surface of the non-woven fabric. Component (A) is contained in the membrane at a ratio of 0.3 to 5.0% by mass, and component (A) and particles (B) are contained in the membrane at a total ratio of 30 to 90% by mass, the mass ratio (A / B) is in the range of 0.01 to 0.2, and the filter air permeability is 0.05 to 14 ml / cm 2 / sec. C p F 2p+1 ‑O‑C q F 2q ‑O‑C r F 2r ‑X‑Y (1)

Description

Technical Field

[0001] The present invention relates to an oil-water separation filter and a method for manufacturing the same, wherein the oil-water separation filter is capable of separating a liquid containing water and oil, such as emulsified oil or water-soluble oil, into water and oil. More specifically, the present invention relates to an oil-water separation filter having a water-repellent and oil-repellent film formed on the fiber surface of a nonwoven fabric, wherein the water-repellent and oil-repellent film has water repellency and oil repellency (hereinafter, sometimes referred to as water-repellent and oil-repellent). Background Art

[0002] Generally, a liquid containing water and oil (hereinafter sometimes simply referred to as a liquid) is classified into floating oil in which oil floats on the water surface, dispersed oil in which oil particles float in water, and emulsified oil or water-soluble oil in which oil and water are mixed and emulsified, according to the mixing state of the oil and water.

[0003] The applicant has proposed an oil-water separation filter, which is an oil-water separation filter comprising a nonwoven fabric having a plurality of pores formed between fibers, wherein the plurality of pores penetrate between a side into which a liquid containing water and oil flows and another side opposite to the side, and the oil-water separation filter is characterized in that a plurality of pores are formed between fibers on the surface of the fibers at a rate of 1 m 2 The nonwoven fabric is formed into an oil-water separation membrane (equivalent to the "water-repellent and oil-repellent membrane" of the present invention) at a ratio of 0.1 to 30 g, the oil-water separation membrane having a silica sol hydrolyzate, the silica sol hydrolyzate containing a fluorinated silane represented by the following formula (28) having both water-repellent and oil-repellent functions, the fluorinated silane being contained in the silica sol hydrolyzate at a ratio of 0.01 to 10% by mass, and the air permeability of the oil-water separation filter being 0.05 to 10 ml / cm 2 / sec, the fluorinated silane contains a perfluoroamine structure (see Patent Document 1 (Claim 1, paragraph

[0016] )). In the formula (28), E is a hydrocarbon group having 2 to 10 carbon atoms and contains one or more bonds selected from ether bonds, CO-NH bonds, and O-CO-NH bonds.

[0004] [Chemistry 9]

[0005]

[0006] In the oil-water separation filter, when the liquid flows into the oil-water separation filter, in the case where the oil particles of the liquid containing water and oil are larger than the pore diameter, the passage of the oil particles of the liquid containing water and oil will be physically blocked. Moreover, even if the oil particles of the liquid containing water and oil are slightly smaller than the pore diameter, the fiber surface of the non-woven fabric will chemically repel the oil particles of the water-soluble oil. On the other hand, the materials showing water and oil repellency represented by polytetrafluoroethylene and the like are difficult to impart water permeability to the non-woven fabric because they do not have hydroxyl groups, but the invention proposed by the above-mentioned applicant can impart water permeability to the non-woven fabric because the oil-water separation membrane is mainly composed of silica sol hydrolyzate having hydroxyl groups. As a result, even if the liquid containing water and oil is emulsified oil or water-soluble oil, the oil will accumulate in the oil-water separation filter, and the water can be separated into water and oil by passing through the oil-water separation filter. Furthermore, since the oil-water separation membrane contains the silica sol hydrolyzate as a main component, the oil-water separation membrane is firmly adhered to the fiber surface of the nonwoven fabric and has durability.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent document 1: Japanese Patent Application Publication No. 2019-42707. Summary of the invention

[0010] Technical problem to be solved by the invention

[0011] However, the fluorine-containing silane shown in patent document 1 is a perfluoroamine structure, and the perfluoro group is bonded with nitrogen as the center, so it is easy to take a rigid structure. Therefore, if the content of fluorine in the liquid composition is increased, the adhesion of the oil-water separation membrane to the fiber of the non-woven fabric is sometimes reduced, and from the viewpoint of durability, there is still room for improvement. In addition, since it strongly shows water repellency when compared with the fluorine-based compounds of the perfluoroether structure, if the liquid containing water and oil is passed through the oil-water separation filter shown in patent document 1, there is a problem of long liquid flow time.

[0012] An object of the present invention is to provide an oil-water separation filter which has good filtration efficiency for removing oil from a liquid containing water and oil, such as emulsified oil or water-soluble oil, and has no problem with a short liquid flow time. Another object of the present invention is to provide a method for simply manufacturing such an oil-water separation filter.

[0013] Solutions to Solve Problems

[0014] The first aspect of the present invention is an oil-water separation filter, which is an oil-water separation filter comprising a non-woven fabric having a plurality of pores formed between fibers, wherein the plurality of pores penetrate between a side through which a liquid containing water and oil flows in and another side opposite to the side through which the liquid flows out, and the oil-water separation filter is characterized in that a water-repellent and oil-repellent film is formed on the fiber surface of the non-woven fabric, the water-repellent and oil-repellent film comprising oxide particles (B) having an average particle size of 2 nm to 90 nm and a substance (C) containing a carboxyl group and / or an acetyl group (hereinafter referred to as "a substance containing a carboxyl group, etc."), the oxide particles (B) are combined with There is a fluorine-based functional group component (A) containing a perfluoroether structure represented by the following general formula (1) or formula (2), the fluorine-based functional group component (A) is contained in the water-repellent and oil-repellent film at a ratio of 0.3 mass % to 5.0 mass %, the fluorine-based functional group component (A) and the oxide particles (B) are contained in the water-repellent and oil-repellent film at a total ratio of 30 mass % to 90 mass %, the mass ratio (A / B) of the fluorine-based functional group component (A) to the oxide particles (B) is in the range of 0.01 to 0.2, and the air permeability of the oil-water separation filter is 0.05 ml / cm 2 / sec~14ml / cm 2 / Second.

[0015] [Chemistry 1]

[0016] C p F 2p+1 -OC q F 2q -OC r F 2r -XY (1)

[0017] C p F 2p+1 -OC q F 2q -XY (2)

[0018] In the above formula (1) and formula (2), p, q and r are each the same or different integers of 1 to 6, and the perfluoroether group may be linear or branched. In addition, in the above formula (1) and formula (2), X is a hydrocarbon group having 2 to 10 carbon atoms, and may contain one or more bonds selected from ether bonds, CO-NH bonds, O-CO-NH bonds and sulfonamide bonds. Furthermore, in the above formula (1) and formula (2), Y is a main component of a hydrolyzate of silane or a silica sol-gel.

[0019] Further explanation of this Y, Y is the site that is bonded to the oxide particles (B). As a specific example, in the formula (3) or (4) described later, as Y, a structure formed by partial hydrolysis of Z can be cited. In addition, as Y, the main component of the silica sol gel formed by mixing the silane compound of formula (3) or (4) with silicon alkoxides such as tetraethoxysilane and tetramethoxysilane, and hydrolyzing and polymerizing, etc. can also be cited. Further, as Y, the main component of the silica sol gel formed by mixing the silane compound of formula (3) or (4) with silicon alkoxides such as tetraethoxysilane and tetramethoxysilane, and silanes containing ethoxy, vinyl, and ether groups, etc., and hydrolyzing and polymerizing, etc. can also be cited. In addition, the above-mentioned carboxyl-containing substance (C) is an adhesive for making the oxide particles (B) bonded with the above-mentioned fluorine-based functional group component (A) and the substrate of the non-woven fabric close.

[0020] A second aspect of the present invention is an oil-water separation filter, which is the invention based on the first aspect, wherein the oxide particles (B) are oxide particles of one kind selected from Si, Al, Mg, Ca, Ti, Zn and Zr.

[0021] The third aspect of the present invention is an oil-water separation filter, which is an invention based on the first aspect, wherein the aforementioned carboxyl-containing substance (C) is a polyolefin-based aqueous dispersion having a carboxyl group, a self-emulsified liquid of an ethylene-vinyl acetate copolymer, or a self-emulsified liquid of an ethylene-vinyl acetate-acrylic acid copolymer.

[0022] A fourth aspect of the present invention is an oil-water separation filter, which is the invention based on the first aspect, wherein the nonwoven fabric is composed of a single layer or a laminate of a plurality of layers.

[0023] The fifth aspect of the present invention is an oil-water separation filter, which is an invention based on any one of the first or fourth aspects, wherein the fibers constituting the aforementioned non-woven fabric are one or more fibers selected from polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE), glass, alumina, carbon, cellulose, pulp, nylon and metal.

[0024] The sixth aspect of the present invention is a method for manufacturing an oil-water separation filter 13, as Figure 4 As shown, it includes: a process of mixing an aqueous dispersion 54 of fluorine oxide particles, a carboxyl-containing substance 55, and a solvent 56 obtained by mixing water and an alcohol having 1 to 4 carbon atoms and containing 40% by mass or less of an alcohol having 1 to 4 carbon atoms to prepare a liquid composition for forming a water-repellent and oil-repellent film (hereinafter sometimes referred to as a liquid composition) 60; a process of immersing a non-woven fabric 20 in a diluted solution of the liquid composition 60 for forming a water-repellent and oil-repellent film; and a process of dehydrating and drying the immersed non-woven fabric.

[0025] The seventh aspect of the present invention is a method for manufacturing an oil-water separation filter, which is an invention based on the sixth aspect, wherein the aforementioned carboxyl-containing substance (C) is a polyolefin-based aqueous dispersion having a carboxyl group, a self-emulsifying liquid of an ethylene-vinyl acetate copolymer, or a self-emulsifying liquid of an ethylene-vinyl acetate-acrylic acid copolymer.

[0026] The eighth aspect of the present invention is a method for manufacturing an oil-water separation filter, which is an invention based on the sixth aspect, wherein an aqueous dispersion 54 of fluorine oxide particles is prepared by adding a mixed fluorine-based compound 52 to an aqueous dispersion 51 of oxide particles and adding a mixed catalyst 53 to the mixed solution.

[0027] A ninth aspect of the present invention is a method for manufacturing an oil-water separation filter, which is the invention based on the sixth aspect, wherein the oxide particles are oxide particles of one kind selected from Si, Al, Mg, Ca, Ti, Zn and Zr.

[0028] Effects of the Invention

[0029] In the oil-water separation filter of the first aspect of the present invention, when a liquid containing water and oil flows into the oil-water separation filter from one side, when the oil particles in the liquid are larger than the pore diameter, the passage of the oil particles in the liquid is physically prevented. Moreover, even when the oil particles in the liquid are slightly smaller than the pore diameter, the fiber surface of the non-woven fabric chemically repels the oil particles of the water-soluble oil. In addition, the water-repellent and oil-repellent film comprises oxide particles (B) with an average particle size of 2nm to 90nm and carboxyl-containing substances (C) combined with fluorine-based functional group components (A), so the formed film has high water repellency and oil repellency. In addition, during film formation, the oxide particles (B) with an average particle size of 2nm to 90nm are combined with each other in the film through carboxyl-containing substances (C), so that the strength of the film and the adhesion of the film can be improved. The oil-water separation filter has the advantages of good filtration efficiency for removing oil from a liquid containing water and oil and short liquid flow time.

[0030] In the oil-water separation filter of the second aspect of the present invention, the oxide particles contained in the water-repellent and oil-repellent membrane are oxide particles of one type selected from Si, Al, Mg, Ca, Ti, Zn and Zr, so oxide particles suitable for the use environment of the oil-water separation filter can be included from a variety of oxide particles.

[0031] In the oil-water separation filter of the third aspect of the present invention, the carboxyl-containing substance is a polyolefin-based aqueous dispersion having a carboxyl group, a self-emulsifying liquid of an ethylene-vinyl acetate copolymer, or a self-emulsifying liquid of an ethylene-vinyl acetate-acrylic acid copolymer. Therefore, the aqueous dispersion or self-emulsifying liquid acts as a binder for the fluorine-containing oxide particles, and when the liquid composition is formed into a film on the surface of the substrate, the film can also be firmly bonded to the surface of the substrate.

[0032] In the oil-water separation filter of the fourth aspect of the present invention, when the non-woven fabric is composed of a single layer, it becomes an oil-water separation filter with a simple structure. When the non-woven fabric is composed of a multi-layer stack, each layer can be constructed according to the particle size of the oil particles in the liquid containing water and oil flowing in, the concentration of the oil component, etc.

[0033] In the oil-water separation filter of the fifth aspect of the present invention, the material of the fibers constituting the non-woven fabric can be selected from polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE), glass, alumina, carbon, cellulose, pulp, nylon and metal according to the particle size of the oil particles in the liquid containing water and oil flowing in, the concentration of the oil, etc.

[0034] In the method for the 6th viewpoint of the present invention, by mixing the aqueous dispersion of fluorine oxide particles, carboxylic material etc. and solvent and preparing water-repellent and oil-repellent film-forming liquid composition, nonwoven fabric is impregnated in the diluent of the water-repellent and oil-repellent film-forming liquid composition, nonwoven fabric is deliquated and dried, thus manufacturing oil-water separation filter, therefore the first, manufacturing is simple. The second, water-repellent and oil-repellent film can be uniformly formed on the fiber surface of nonwoven fabric. In addition the third, because the oxide particles of the particle surface being water-repellent and oil-repellent are present in carboxylic material etc., therefore while maintaining water-repellent and oil-repellent, the air permeability of nonwoven fabric is easily reduced.

[0035] In the method for manufacturing an oil-water separation filter according to the seventh aspect of the present invention, the carboxyl-containing substance is a polyolefin-based aqueous dispersion having a carboxyl group, a self-emulsifying liquid of an ethylene-vinyl acetate copolymer, or a self-emulsifying liquid of an ethylene-vinyl acetate-acrylic acid copolymer. Therefore, the aqueous dispersion or self-emulsifying liquid acts as a binder for the fluorine-containing oxide particles, and when the liquid composition is formed into a film on the surface of the substrate, the film can also be firmly bonded to the surface of the substrate.

[0036] In the method for producing an oil-water separation filter according to the eighth aspect of the present invention, a fluorine-containing compound is added to the aqueous dispersion of oxide particles, and a mixed catalyst is added to the mixed solution. Therefore, an aqueous dispersion in which fluorine-containing oxide particles are uniformly dispersed can be obtained.

[0037] In the manufacturing method of the oil-water separation filter of the 9th aspect of the present invention, the oxide particles are oxide particles of one type selected from Si, Al, Mg, Ca, Ti, Zn and Zr. Therefore, an oil-water separation filter containing oxide particles suitable for the use environment of the oil-water separation filter can be manufactured from a variety of oxide particles.

[0038] In the manufacture method of the oil-water separation filter of any one of the 6th to 9th viewpoints of the present invention, since the water-repellent and oil-repellent film is also bonded to the fiber surface of the nonwoven fabric while reducing the air permeability, the oil-repellent performance can be fully obtained. Further, by oxide particles, the effect of improving the abrasion strength of the film can also be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 : is a structural diagram of an oil-water separation device having an oil-water separation filter according to an embodiment of the present invention.

[0040] Figure 2 : This is a cross-sectional view of a single-layer nonwoven fabric according to the present embodiment.

[0041] Figure 3 : This is a cross-sectional view of the two-layer nonwoven fabric of this embodiment.

[0042] Figure 4 : is a flow chart for manufacturing the oil-water separation filter of this embodiment.

[0043] Figure 5 : is a diagram showing the structure of an apparatus used in the filtration test of each oil-water separation filter of the embodiment and the comparative example. DETAILED DESCRIPTION

[0044] Next, a mode for carrying out the present invention will be described with reference to the drawings.

[0045] 〔Oil-water separation device〕

[0046] like Figure 1 As shown, the oil-water separator 10 of this embodiment includes: a cylindrical liquid inflow portion 12 into which a liquid 11 containing water and oil flows; a sheet-shaped oil-water separation filter 13 that separates the oil in the liquid 11 from the water; a funnel-shaped water collection portion 16 that collects the water 14 separated from the oil-water separation filter 13; and a bottomed cylindrical water storage portion 17 that stores the water 14 that flows in from the water collection portion 16. A liquid inflow pipe 18 is provided above the liquid inflow portion 12, and a drain pipe 19 is provided at the bottom of the water storage portion 17.

[0047] In the case where the oil-water separation filter 13 is only composed of non-woven fabric, although not shown in the figure, a porous metal support plate for reinforcing the non-woven fabric is arranged as a whole under the oil-water separation filter 13 so that the oil-water separation filter 13 can withstand the pressure of the liquid in the liquid inlet part 12. The oil-water separation filter 13 and the support plate are clamped by the liquid inlet part 12 and the water collection part 16.

[0048] 〔Oil-water separation filter〕

[0049] like Figure 2As shown in FIG. 1 , the oil-water separation filter 13 of this embodiment includes a nonwoven fabric 20 and a water-repellent and oil-repellent film 21 formed on the fiber surface of the nonwoven fabric. The nonwoven fabric 20, which is a main component of the oil-water separation filter 13, has a surface 20a into which a liquid containing water and oil flows, and another surface 20b opposite to the surface 20a from which the filtrate flows out, and is composed of a single layer. Figure 3 As shown in the figure, the nonwoven fabric can also be made into a two-layer laminate of an upper nonwoven fabric 30 and a lower nonwoven fabric 40 to form the oil-water separation filter 23. In this case, the upper surface of the nonwoven fabric 30 of the upper layer becomes the side 30a into which the liquid containing water and oil flows, and the lower surface of the nonwoven fabric 40 of the lower layer becomes the other side 40b opposite to the side 30a from which the filtrate flows out. The lower surface 30b of the nonwoven fabric 30 is in close contact with the upper surface 40a of the nonwoven fabric 40. It should be noted that the laminate is not limited to two layers, and can also be composed of multiple layers such as three layers and four layers.

[0050] like Figure 2 As shown in the enlarged view in the center, the nonwoven fabric 20 is formed by entanglement of a plurality of fibers 20c, and pores 20d are formed between the fibers. The pores 20d penetrate between one side 20a and the other side 20b of the nonwoven fabric 20. A water-repellent and oil-repellent film 21 is formed on the surface of the fibers 20c of the nonwoven fabric. The unit weight of the nonwoven fabric is preferably 10 g / m 2 ~400g / m 2 The range is preferably 100 g / m 2 ~350g / m 2 range, but is not limited to this range. The water-repellent and oil-repellent film 21 comprises oxide particles (B) having an average particle size of 2nm to 90nm and carboxyl-containing substances, etc. (C). The fluorine-based functional group component (A) shown in the above-mentioned general formula (1) or formula (2) is combined with the oxide particles (B). The fluorine-based functional group component (A) is contained in the water-repellent and oil-repellent film 21 at a ratio of 0.3% to 5.0% by mass, preferably 0.4% to 4.0% by mass. In addition, carboxyl-containing substances, etc. (C) are contained in the water-repellent and oil-repellent film 21 at a ratio of 10% to 70% by mass, preferably 15% to 65% by mass. In addition, the fluorine-based functional group component (A) and the oxide particles (B) are contained in the water-repellent and oil-repellent film 21 at a total ratio of 30% to 90% by mass, preferably 35% to 85% by mass. Furthermore, the mass ratio (A / B) of the fluorine-containing functional group component (A) to the oxide particles (B) is in the range of 0.01 to 0.2, preferably 0.014 to 0.18.

[0051] like Figure 2As shown in the further enlarged view of the upper part, the water-repellent and oil-repellent film 21 is formed by bonding a plurality of oxide particles 21a whose particle surface is covered with fluorine-based functional group components with 21b such as carboxyl-containing substances as adhesives. The water-repellent and oil-repellent film 21 forms a thick film in appearance due to the oxide particles 21a, which can narrow the pores 20d between the fibers. In addition, the film thickness can be controlled by changing the particle size of the oxide particles and the containing ratio of the oxide particles in the film component.

[0052] In the state of the oil-water separation filter 13 with the water-repellent and oil-repellent film 21 formed on the fiber surface, the nonwoven fabric 20 has a 0.05 ml / cm 2 / sec~14ml / cm 2 / sec air permeability. Air permeability is less than 0.05ml / cm 2 / second, or the weight per unit area exceeds 400g / m 2 When the water permeability is poor, it is difficult to obtain the filtrate. The air permeability exceeds 14ml / cm 2 / second, or the unit area weight of the non-woven fabric is less than 10g / m 2 When the size of the pores 20d of the nonwoven fabric becomes much larger than the oil particles 22 in the mixed liquid, the oil particles 22 pass through the pores of the nonwoven fabric together with the water and leak out of the oil-water separation filter 13, making it impossible to separate the water and the oil. The air permeability is preferably 0.1ml / cm 2 / sec~10ml / cm 2 / sec. The air permeability is measured using a Frazier-type tester described in JIS-L1913:2000.

[0053] When the content of the fluorine-based functional group component (A) in the water-repellent and oil-repellent film 21 is less than 0.3% by mass, the oil-repellent effect is poor, and the performance of repelling oil particles becomes insufficient. When the content of the fluorine-based functional group component (A) exceeds 5.0% by mass, the film-forming property is poor, and the adhesion of the water-repellent and oil-repellent film to the nonwoven fabric deteriorates.

[0054] The average particle size of the oxide particles (B) contained in the water-repellent and oil-repellent film 21 is in the range of 2nm to 90nm, preferably 2nm to 85nm. When the average particle size is less than 2nm, it is easy to cause agglomeration of the oxide particles and it is difficult to disperse in the medium. When it exceeds 90nm, the oxide particles (B) fall off from the water-repellent and oil-repellent film. When the content ratio of carboxyl-containing substances (C) in the water-repellent and oil-repellent film 21 is less than 10% by mass, the strength of the film and the adhesion of the film are prone to deterioration. If it exceeds 70% by mass, it is difficult to give oil repellency to the film. In the water-repellent and oil-repellent film 21, when the total amount of the fluorine-based functional group component (A) and the oxide particles (B) is less than 30% by mass, the oil repellency of the water-repellent and oil-repellent film is reduced. In addition, if the total amount exceeds 90% by mass, the content of carboxyl-containing substances (C) is relatively low, and the water-repellent and oil-repellent film cannot be firmly bonded to the non-woven surface. In addition, when the mass ratio (A / B) is less than 0.01, the oil repellency of the water-repellent and oil-repellent film is poor, and when it exceeds 0.2, the adhesion of the water-repellent and oil-repellent film to the fiber surface is reduced. It should be noted that in this specification, the average particle size of the oxide particles refers to the average value of the size obtained by measuring the particle size of 200 points using image analysis in the particle shape observed using a transmission electron microscope (TEM).

[0055] The function of the oil-water separator 10 having such an oil-water separator filter 13 will be described. Figure 1 As shown, first, the oil-water separation filter 13 is clamped by the liquid inlet 12 and the water collecting part 16. Then, the liquid 11 containing water and oil is supplied to the liquid inlet 12 from the inlet pipe 18. The liquid in this embodiment is a water-soluble oil. The liquid 11 stored in the liquid inlet 12 is in contact with one side 20a ( Figure 2 Here, since the oil-water separation filter 13 has a predetermined air permeability and the water-repellent and oil-repellent film 21 exhibits water-repellent and oil-repellent properties, water (not shown) in the water-soluble oil is repelled by the water-repellent and oil-repellent film 21, and at the same time, due to the presence of hydroxyl groups of carboxyl-containing substances, the water-soluble oil is repelled by the water-soluble oil. Figure 2 The water 14 reaches the other side 20b through the pores 20d formed between the fibers 20c and the fibers 20c as shown in the enlarged view of the nonwoven fabric 20, and drips from there to be collected in the water collecting portion 16. The collected water 14 flows from the water collecting portion 16 to the water storage portion 17 and accumulates in the water storage portion 17. When a certain amount of water 14 is stored in the water storage portion 17, the drain valve (not shown) is opened, and the water 14 separated from the oil is obtained from the drain pipe 19.

[0056] On the other hand, Figure 2As shown in the enlarged view of FIG, due to the oil repellency of the water-repellent and oil-repellent film 21 formed on the fiber surface of the nonwoven fabric 20, and also due to the prescribed air permeability of the oil-water separation filter, the oil particles 22 in the liquid cannot pass through the oil-water separation filter 13 even if the particle size is slightly smaller than the pore size of the pore 20d, and stay between the fibers 20c and 20c of the nonwoven fabric 20. Since the water-repellent and oil-repellent film 21 contains oxide particles 21a, the film becomes uneven, and the degree of adhesion of the oil particles 22 to the film is low. Thereby, the oil particles 22 are captured by the nonwoven fabric. The oil-water separation filter 13 is regularly removed from the oil-water separation device 10 to recover the oil accumulated in the nonwoven fabric 20.

[0057] [Method for manufacturing oil-water separation filter]

[0058] The oil-water separation filter is generally manufactured by the following method.

[0059] like Figure 4 As shown, a fluorine compound 52 containing a fluorine functional group component (A) is mixed in an aqueous dispersion 51 of oxide particles, and a catalyst 53 is further mixed to prepare an aqueous dispersion 54 of fluorine oxide particles. A liquid composition 60 for forming a water-repellent and oil-repellent film is prepared by mixing the aqueous dispersion 54, a carboxyl-containing substance 55, and a solvent 56. A liquid is prepared by diluting the liquid composition 60 for forming a water-repellent and oil-repellent film with a solvent 61 formed by mixing water and an alcohol having a carbon number of 1 to 4 in the range of a boiling point of less than 120°C, immersing the nonwoven fabric 20 in the diluted liquid 62, lifting it from the diluted liquid, unfolding the nonwoven fabric on a horizontal metal mesh (gold mesh) or the like in the atmosphere at room temperature, removing the liquid until a certain amount of liquid is reached, and drying, thereby manufacturing an oil-water separation filter 13.

[0060] 〔Preparation of non-woven fabric〕

[0061] First, prepare a 0.05 ml / cm 2 / sec~18ml / cm 2 Specifically, a nonwoven fabric having an air permeability of 0.05 ml / cm 2 / sec~14ml / cm 2 When the water-repellent and oil-repellent film is formed as a thick film, a nonwoven fabric with high air permeability is selected, and when the water-repellent and oil-repellent film is formed as a thin film, a nonwoven fabric with low air permeability is selected.

[0062] As the nonwoven fabric, for example, there are cellulose mixed ester membrane filters, glass fiber filter paper, and nonwoven fabrics mixed with polyethylene terephthalate fibers and glass fibers (produced by Anji Filter Paper Co., Ltd., trade name: 340). In this way, the nonwoven fabric is made of one or more fibers selected from polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE), glass, alumina, carbon, cellulose, pulp, nylon and metal. The fiber can also be a fiber mixed with two or more fibers. In order to obtain the above-mentioned air permeability, the thickness of the fiber (fiber diameter) is preferably 0.01μm to 10μm, but it is not limited to this range. For the thickness of the nonwoven fabric, when the oil-water separation filter is a single layer, it is preferably 0.2mm to 0.8mm, and when it is a multi-layer laminate, it is preferably a thickness of 0.2mm to 1.6mm.

[0063] [Method for producing a liquid composition for forming a water- and oil-repellent film]

[0064] [Preparation of aqueous dispersion of oxide particles]

[0065] First, oxide particles are dispersed in an aqueous solvent to prepare an aqueous dispersion of oxide particles. Examples of oxide particles include SiO 2 、Al 2 O 3 , MgO, CaO, TiO 2 、ZnO、ZrO 2 As the aqueous solvent, water or a mixed solvent of water and an alcohol having 1 to 4 carbon atoms can be exemplified. As the water, in order to prevent impurities from being mixed in, ion exchange water, pure water, etc. are preferably used.

[0066] [Preparation of aqueous dispersion of fluorine oxide particles]

[0067] Next, a fluorine compound containing a fluorine-containing functional group component represented by the above formula (1) or formula (2) is added to the prepared aqueous dispersion of the oxide particles to synthesize a composite material in which the oxide particles and the fluorine-containing functional group component are nanocomposite. In order to further promote the reaction, a catalyst is added. Thus, an aqueous dispersion of fluorine-containing oxide particles is prepared.

[0068] Examples of the catalyst include organic acids, inorganic acids, bases, and titanium compounds. Examples of organic acids include formic acid and oxalic acid. Examples of inorganic acids include hydrochloric acid, nitric acid, and phosphoric acid. Examples of bases include sodium hydroxide, lithium hydroxide, magnesium hydroxide, potassium hydroxide, calcium hydroxide, and ammonia. Examples of titanium compounds include tetrapropoxytitanium, tetrabutoxytitanium, tetraisopropoxytitanium, and titanium lactate. The catalyst is not limited to the above substances.

[0069] The fluorine compound containing a fluorine functional group component is represented by the following general formula (3) or formula (4). More specifically, the perfluoroether group in these formulas (3) or (4) includes perfluoroether structures represented by the following formulas (5) to (13).

[0070] [Chemistry 2]

[0071]

[0072] [Chemistry 3]

[0073] C 2 F 5 -OC 2 F 4 -OC 2 F 4 - (5)

[0074] C 2 F 5 -OC 3 F 6 -OC 2 F 4 - (6)

[0075] C 3 F 7 -OC 3 F 6 -OC 2 F 4 - (7)

[0076] C 4 F 9 -OC 3 F 6 -OC 2 F 4 - (8)

[0077] C 3 F 7 -OC 2 F 4 -OC 2 F 4 - (9)

[0078] [Chemistry 4]

[0079] C 2 F 5 -OC 2 F 4 - (10)

[0080] C 2 F 5 -OC 3 F 6 - (11)

[0081] C 3 F 7 -OC 3 F 6 - (12)

[0082] C 3 F 7 -OC 4 F 8 - (13)

[0083] In addition, as X in the above formula (3) and formula (4), structures represented by the following formulas (14) to (18) can be cited. It should be noted that the following formula (14) shows an example including an ether bond, the following formula (15) shows an example including an ester bond, the following formula (16) shows an example including an amide bond, the following formula (17) shows an example including a carbamate bond, and the following formula (18) shows an example including a sulfonamide bond.

[0084] [Chemistry 5]

[0085]

[0086] Herein, in the above formulas (14) to (18), R 2 and R 3 is a hydrocarbon group having 0 to 10 carbon atoms, R 4 is a hydrogen atom or a hydrocarbon group having 1 to 6 carbon atoms. 3 Examples of the hydrocarbon group include alkylene groups such as methylene and ethylene. 4 Examples of the hydrocarbon group include phenyl and the like in addition to alkyl groups such as methyl and ethyl.

[0087] In addition, in the above formula (3) and formula (4), R 1 Examples include a methyl group and an ethyl group.

[0088] In the above formula (3) and formula (4), Z is not particularly limited as long as it is a hydrolyzable group that can be hydrolyzed to form a Si-O-Si bond. Specific examples of such hydrolyzable groups include alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, aryloxy groups such as phenoxy, naphthoxy, aralkyloxy groups such as benzyloxy, phenethoxy, and acyloxy groups such as acetoxy, propionyloxy, butyryloxy, valeryloxy, pivaloyloxy, and benzoyloxy. Among them, methoxy and ethoxy are preferably used.

[0089] Herein, as specific examples of the fluorine-based compounds represented by the above formula (3) or formula (4) and containing a fluorine-based functional group component having a perfluoroether structure, for example, the structures represented by the following formulas (19) to (27) can be cited. It should be noted that in the following formulas (19) to (27), R is a methyl group or an ethyl group.

[0090] [Chemistry 6]

[0091]

[0092] C 3 F 7 -OC 3 F 6 -CH 2 -OC 3 H 6 -Si-(OR) 3 (twenty three)

[0093] [Chemistry 7]

[0094]

[0095] As described above, the fluorine-based compound contained in the liquid composition for forming a water- and oil-repellent film of the present embodiment has a perfluoroether group having a plurality of short-chain perfluoroalkyl and perfluoroalkylene groups having a carbon number of 6 or less bonded to an oxygen atom in the molecule, and the fluorine content in the molecule is high, so that the formed film can be endowed with excellent water- and oil-repellent properties.

[0096] 〔Substances containing carboxyl groups, etc〕

[0097] The carboxyl-containing material is a polyolefin-based aqueous dispersion having a carboxyl group, a self-emulsified liquid of an ethylene-vinyl acetate copolymer, or a self-emulsified liquid of an ethylene-vinyl acetate-acrylic acid copolymer. As commercially available products, commercially available products of ethylene-vinyl acetate systems include SEPOLSION VA406N, SEPOLSION VA407N (all manufactured by Sumitomo Seika Chemicals Co., Ltd.), Sumikaflex S-201HQ, S-465HQ, S-408HQE (all manufactured by Sumitomo Chemical Co., Ltd.), AQUATEX EC-1800, EC-1200 (all manufactured by Japan Controlled Chemical Co., Ltd.). Commercially available products of polyolefins having a carboxyl group include ZAIKTHENE A, ZAIKTHENE L, and ZAIKTHENE N (all manufactured by Sumitomo Seika Chemicals Co., Ltd.), and commercially available products of ethylene-vinyl acetate-acrylic acid include Sumikaflex S-900HL (manufactured by Sumitomo Chemical Co., Ltd.).

[0098] [Liquid composition for forming water- and oil-repellent film]

[0099] The water-repellent and oil-repellent film-forming liquid composition of the present embodiment is manufactured by the above-mentioned manufacturing method, comprising oxide particles (B) combined with the above-mentioned fluorine-based functional group component (A), carboxyl-containing substances (C), and solvent (D). The fluorine-based functional group component (A) has a perfluoroether structure shown in the above-mentioned general formula (1) or formula (2), and is included in the water-repellent and oil-repellent film-forming liquid composition with 0.3 mass % to 5.0 mass %. In addition, when the total amount of components except the solvent (D) is set to 100 mass %, carboxyl-containing substances (C) are included in the water-repellent and oil-repellent film-forming liquid composition with 10 mass % to 70 mass %. Further, when the total amount of components except the solvent (D) is set to 100 mass %, the total content ratio of the fluorine-based functional group component (A) and the oxide particles (B) is 30 mass % to 90 mass % in the liquid composition. Furthermore, the mass ratio (A / B) of the fluorine-based functional group component (A) to the oxide particles (B) is in the range of 0.01 to 0.2. The above-mentioned solvent (D) is a solvent in which the content of the alcohol with carbon numbers of 1 to 4 is 40% by mass or less, which is formed by mixing water and an alcohol with carbon numbers of 1 to 4. The content of the alcohol with carbon numbers of 1 to 4 is set to 40% by mass or less for operational safety and storage stability of the liquid composition. In addition, by forming a mixed solvent formed by mixing water and an alcohol with carbon numbers of 1 to 4, the drying speed is increased and the film-forming property is improved. As alcohols with carbon numbers of 1 to 4, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and 2-methyl-2-propanol can be cited.

[0100] Specific examples of the perfluoroether structure represented by the general formula (1) or (2) include the structures represented by the formulae (19) to (27).

[0101] The water-repellent and oil-repellent film-forming liquid composition of the present embodiment except solvent contains carboxyl-containing substances as main components, and further contains oxide particles, so the strength of the water-repellent and oil-repellent film is improved, and a high-strength water-repellent and oil-repellent film having excellent adhesion to the fiber of nonwoven fabric and being difficult to peel off can be obtained. In addition, the water-repellent and oil-repellent film-forming liquid composition contains the fluorine-based functional group component of the perfluoroether structure shown in the above-mentioned general formula (1) or formula (2), so it has an oil-repellent effect.

[0102] [Method for forming a water- and oil-repellent film on the fiber surface of nonwoven fabric]

[0103] In order to form a water-repellent and oil-repellent film on the fiber surface of the nonwoven fabric of the present embodiment, a liquid composition for forming a water-repellent and oil-repellent film is prepared by diluting a solvent obtained by mixing water and an alcohol having a carbon number of 1 to 4 and a boiling point of less than 120°C. The mixing ratio of water and alcohol in the solvent (water:alcohol) is 1:0 to 5 in terms of mass ratio. In addition, the mass ratio of the solvent to the liquid composition (liquid composition: solvent) is 1:0.1 to 10. The nonwoven fabric is immersed in the dilution prepared in this way, lifted up from the dilution, and spread on a horizontal metal wire mesh or the like in the air at room temperature to remove the liquid until a certain amount of liquid is reached. As another method, the lifted nonwoven fabric is shaken to remove excess liquid, or the lifted nonwoven fabric is passed through a liquid squeezer (press) for dehydration. The dehydrated nonwoven fabric is dried in the air at a temperature of 25°C to 140°C for 0.5 hours to 24 hours. Thus, as Figure 2 As shown in the enlarged view in the center, a water-repellent and oil-repellent film 21 is formed on the surface of the fiber 20c constituting the nonwoven fabric 20. When the amount of liquid removal is small, the water-repellent and oil-repellent film is formed as a thick film on the fiber surface of the nonwoven fabric, and when the amount of liquid removal is large, the water-repellent and oil-repellent film is formed as a thin film on the fiber surface of the nonwoven fabric.

[0104] Example

[0105] Next, the embodiments of the present invention are described in detail together with comparative examples. First, Synthesis Examples 1 to 6 and Comparative Synthesis Examples 1 to 3 for preparing aqueous dispersions of fluorine oxide particles are described, and then Examples 1 to 8 and Comparative Examples 1 to 4 for preparing liquid compositions for forming water- and oil-repellent films and manufacturing oil-water separation filters using these Synthesis Examples and Comparative Synthesis Examples are described.

[0106] [Synthesis Examples 1 to 6 for preparing aqueous dispersions of fluorine-containing oxide particles, Comparative Synthesis Examples 1 to 3]

[0107] <Synthesis example 1>

[0108] An aqueous dispersion of silicon dioxide (ST-OXS, manufactured by Nissan Chemical Co., Ltd., SiO 2 In a beaker containing 50.0 g of fluorine-containing compound (10%), 0.08 g of the fluorine-containing compound represented by the above formula (19) was added and mixed. Next, 0.005 g of nitric acid was added and mixed at 40° C. for 2 hours to obtain an aqueous dispersion of silica particles (aqueous dispersion of fluorine-containing silica particles) in which silica particles and the fluorine-containing compound were combined. The mass ratio (A / B) of the fluorine-containing functional group component (A) to the silica as oxide particles (B) was 0.01.

[0109] <Synthesis example 2>

[0110] An aqueous dispersion of silicon dioxide (ST-XS, manufactured by Nissan Chemical Co., Ltd., SiO 2 In a beaker containing 50.0 g of fluorine-containing compound (concentration 30%), 0.45 g of the fluorine-containing compound represented by the above formula (20) was added and mixed. Next, 0.005 g of nitric acid was added, and then the same operation as in Synthesis Example 1 was performed to obtain an aqueous dispersion of silica particles (aqueous dispersion of fluorine-containing silica particles). The mass ratio (A / B) was 0.03.

[0111] <Synthesis Example 3>

[0112] An aqueous dispersion of silicon dioxide (ST-ZL, manufactured by Nissan Chemical Co., Ltd., SiO 2 In a beaker containing 50.0 g of fluorine-containing compound (concentration 30%), 0.75 g of the fluorine-containing compound represented by the above formula (21) was added and mixed. Next, 0.005 g of nitric acid was added, and then the same operation as in Synthesis Example 1 was performed to obtain an aqueous dispersion of silica particles (aqueous dispersion of fluorine-containing silica particles). The mass ratio (A / B) was 0.05.

[0113] <Synthesis example 4>

[0114] In the presence of an aqueous dispersion of zirconium dioxide (SZR-W, manufactured by Sakai Chemical Co., Ltd., ZrO 2 In a beaker containing 50.0 g of fluorine-containing compound (concentration 30%), 3.00 g of the fluorine-containing compound represented by the above formula (27) was added and mixed. Next, 0.009 g of nitric acid was added, and then the same operation as in Synthesis Example 1 was performed to obtain an aqueous dispersion of zirconium dioxide particles (aqueous dispersion of fluorine-containing zirconium dioxide particles). The mass ratio (A / B) of the fluorine-containing functional group component (A) to the zirconium dioxide as oxide particles (B) was 0.19.

[0115] <Synthesis example 5>

[0116] An aqueous dispersion of titanium dioxide (TKS-203, manufactured by TIKA Corporation, TiO 2 In a beaker containing 50.0 g of fluorine-containing compound (20% concentration), 0.30 g of the fluorine-containing compound represented by the above formula (27) was added and mixed. Next, 0.001 g of nitric acid was added, and then the same operation as in Synthesis Example 1 was performed to obtain an aqueous dispersion of titanium dioxide particles (aqueous dispersion of fluorine-containing titanium dioxide particles). The mass ratio (A / B) of the fluorine-containing functional group component (A) to the titanium dioxide as oxide particles (B) was 0.03.

[0117] <Synthesis Example 6>

[0118] In a beaker to which 50.0 g of an aqueous dispersion of zinc oxide having an average particle size of 25 nm (MZ-500, manufactured by Teika Co., Ltd., ZnO concentration 30%) was added, 0.45 g of the fluorine compound represented by the above formula (27) was added and mixed. Next, 0.005 g of nitric acid was added, and then the same operation as in Synthesis Example 1 was performed to obtain an aqueous dispersion of zinc oxide particles (an aqueous dispersion of fluorine-containing zinc oxide particles). The mass ratio (A / B) of the fluorine-based functional group component (A) to the zinc oxide as the oxide particles (B) was 0.03.

[0119] <Comparative Synthesis Example 1>

[0120] An aqueous dispersion of titanium dioxide (R32, manufactured by Sakai Chemical Co., Ltd., TiO 2 In a beaker containing 50.0 g of fluorine-containing functional group component (A) and 0.45 g of the fluorine-containing compound represented by the above formula (27) was added and mixed. Next, 0.005 g of nitric acid was added, and then the same operation as in Synthesis Example 1 was performed to obtain an aqueous dispersion of titanium dioxide particles (an aqueous dispersion of fluorine-containing titanium dioxide particles). The mass ratio (A / B) of the fluorine-containing functional group component (A) to the titanium dioxide as oxide particles (B) was 0.03.

[0121] <Comparative Synthesis Example 2>

[0122] In a beaker having added thereto 50.0 g of the same aqueous dispersion of silica as in Synthesis Example 2, 0.08 g of the fluorine compound represented by the above formula (27) was added and mixed. Next, 0.005 g of nitric acid was added, and then the same operation as in Synthesis Example 1 was performed to obtain an aqueous dispersion of silica particles (aqueous dispersion of fluorine-containing silica particles). The mass ratio (A / B) was 0.005.

[0123] <Comparative Synthesis Example 3>

[0124] In a beaker having added thereto 50.0 g of the same aqueous dispersion of silica as in Synthesis Example 2, 3.45 g of the fluorine compound represented by the above formula (27) was added and mixed. Next, 0.011 g of nitric acid was added, and then the same operation as in Synthesis Example 1 was performed to obtain an aqueous dispersion of silica particles (aqueous dispersion of fluorine-containing silica particles). The mass ratio (A / B) was 0.22.

[0125] The contents of the aqueous dispersions of fluorine-containing oxide particles of Synthesis Examples 1 to 6 and Comparative Synthesis Examples 1 to 3 are shown in Table 1. In Table 1, R in the fluorine-containing silanes represented by Formulas (19) to (21) and (27) as fluorine-containing compounds is ethyl.

[0126] [Table 1]

[0127]

[0128] (Note) (A) is a fluorine-based functional group component, and (B) is an oxide particle.

[0129] [Examples 1 to 8 and Comparative Examples 1 to 4 for preparation of a liquid composition for forming a water- and oil-repellent film and production of an oil-water separation filter]

[0130] <Example 1>

[0131] 10.57 g of the aqueous dispersion of fluorinated silica particles obtained in Synthesis Example 1, 5.00 g of SEPOLSION VA406N (manufactured by Sumitomo Seika Co., Ltd.), which is a self-emulsifying liquid of ethylene-vinyl acetate copolymer as a substance containing a carboxyl group, and 789.43 g of a solvent obtained by mixing 513.13 g of water and 276.30 g of industrial alcohol (AP-7, manufactured by Japan Alcohol Industries Co., Ltd.) were mixed to prepare a water-repellent and oil-repellent film-forming liquid composition. 250.00 g of the obtained water-repellent and oil-repellent film-forming liquid composition was diluted with 50.00 g of a mixed solvent of water and industrial alcohol (by mass ratio, water: industrial alcohol = 1:1) to prepare a dilution.

[0132] As the substrate of the oil-water separation filter, a laminate of a nonwoven fabric composed of glass fibers on the upper layer and PET fibers on the lower layer (a two-layer nonwoven fabric) was used. The air permeability of the laminate was 2.1 ml / m 2 / sec. The two layers of nonwoven fabric were immersed in the above dilution, excess liquid was shaken off, and dried at room temperature for 24 hours to produce an air permeability of 2.00 ml / cm 2 / sec oil-water separation filter.

[0133] The contents are shown in Tables 2 and 3 below.

[0134] Table 2 also shows the content ratio of "fluorinated functional group component (A) in the liquid composition excluding the solvent", the content ratio of "carboxyl group-containing substances (C) in the liquid composition excluding the solvent" and the "total content ratio of fluorinated functional group component (A) and oxide particles (B) in the liquid composition excluding the solvent". It should be noted that the content ratio (%) of the fluorine-containing functional group component (A) in the liquid composition excluding the solvent, when expressed in consideration of the content ratio of the carboxyl-containing substance (C), is the percentage of {(A) / [(A)+(B)+(C)]}, the content ratio (%) of the carboxyl-containing substance (C) in the liquid composition excluding the solvent is the percentage of {(C) / [(A)+(B)+(C)]}, and the total content ratio (%) of the fluorine-containing functional group component (A) and the oxide particles (B) in the liquid composition excluding the solvent, when expressed in consideration of the content ratio of the carboxyl-containing substance (C), is the percentage of {[(A)+(B)] / [(A)+(B)+(C)]}.

[0135] [Table 2]

[0136]

[0137] (Note) (A) is a fluorine-based functional group component, (B) is an oxide particle, and (C) is a carboxyl group-containing substance.

[0138] [Table 3]

[0139]

[0140] <Examples 2 to 8 and Comparative Examples 1 to 3>

[0141] As shown in Table 2, in Examples 2 to 6, the aqueous dispersions of fluorine-containing oxide particles obtained in Synthesis Examples 1 to 6 shown in Table 1 were used to determine the weight of each. In Example 7, the aqueous dispersion of fluorine-containing oxide particles obtained in Synthesis Example 1 shown in Table 1 was used to determine the weight. In Example 8, the aqueous dispersion of fluorine-containing oxide particles obtained in Synthesis Example 2 shown in Table 1 was used to determine the weight. In Comparative Examples 1 to 3, the aqueous dispersions of fluorine-containing oxide particles obtained in Comparative Synthesis Examples 1 to 3 shown in Table 1 were used to determine the weight of each.

[0142] As the carboxyl group-containing substance, Sumikaflex S-408HQE (manufactured by Sumitomo Chemical Co., Ltd.), which is a self-emulsifying liquid of ethylene-vinyl acetate copolymer, was used in Examples 2 and 8, and SEPOLSION VA406N (manufactured by Sumitomo Seika Chemicals Co., Ltd.), which is a self-emulsifying liquid of ethylene-vinyl acetate copolymer, was used in Examples 3 to 6 and Comparative Examples 1 to 3, and the weights of each were determined. In Example 7, ZAIKTHENE A (manufactured by Sumitomo Seika Chemicals Co., Ltd.), which is a polyolefin-based aqueous dispersion having a carboxyl group, was used, and the weight thereof was determined.

[0143] As the solvent, a solvent obtained by mixing water and industrial alcohol (AP-7, manufactured by Nippon Alcohol Industries, Ltd.) in the amounts shown in Table 2 was used in Examples 2 to 8 and Comparative Examples 1 to 3.

[0144] In this manner, each water- and oil-repellent film-forming liquid composition of Examples 2 to 8 and Comparative Examples 1 to 3 was prepared.

[0145] Furthermore, as shown in Table 3, the air permeability of the nonwoven fabric before immersion, the type of the base material of the oil-water separation filter, and the air permeability of the oil-water separation filter (after immersion) were selected.

[0146] It should be noted that the nonwoven fabrics used in Example 7 and Comparative Examples 2 and 3 are different from the nonwoven fabrics in Example 1. They are nonwoven fabrics consisting of a layer of mixed fibers of PET fibers and glass fibers (PET: glass = 80:20 by mass ratio), and the air permeability before impregnation is 9.5 ml / cm 2 / sec (Example 7 and Comparative Example 2), 15.0ml / cm 2 / sec (Comparative Example 3). The nonwoven fabric used in Example 8 is a one-layer nonwoven fabric composed of polypropylene (PP) fibers, and the air permeability before impregnation is 14.0 ml / cm 2 / Second.

[0147] Furthermore, the nonwoven fabric was immersed in the diluted liquid of the liquid composition for forming a water-repellent and oil-repellent film obtained in Examples 2 to 8 and Comparative Examples 1 to 3, respectively, in the same manner as in Example 1, and deliquored and dried to obtain oil-water separation filters of Examples 2 to 8 and Comparative Examples 1 to 3 having the air permeabilities shown in Table 3.

[0148] <Comparative Example 4>

[0149] In Comparative Example 4, the same operation as in Example 1 described in Patent Document 1 was performed to obtain a liquid composition for forming a water-repellent and oil-repellent film. Specifically, 8.52 g of a 3-pentamer of tetramethoxysilane (TMOS) as a silicon alkoxide (Mitsubishi Chemical Corporation, trade name: MKC Silicone MS51), 0.48 g of 3-glycidoxypropyltrimethoxysilane (GPTMS: Shin-Etsu Chemical Co., Ltd., trade name: KBM-403) as an ethoxysilane, 0.24 g of a fluorine-containing silane (R: ethyl) represented by the following formula (29) as a fluorine-based compound, and 17.58 g of ethanol (EtOH) (boiling point 78.3° C.) as an organic solvent were mixed, and 3.37 g of ion exchange water was added, and the mixture was stirred at 25° C. for 5 minutes in a removable flask to prepare a mixed solution. In addition, 0.05 g of hydrochloric acid at a concentration of 35% by mass was added to the mixed solution as a catalyst, and the mixture was stirred at 40° C. for 2 hours. Thus, a liquid composition for forming an oil-water separation membrane containing a silica sol hydrolyzate was prepared. As in Example 1, the same nonwoven fabric as in Example 1 was immersed in a dilution of the liquid composition for forming a water-repellent and oil-repellent film, and deliquored and dried to obtain an oil-water separation filter having the characteristics shown in Table 3.

[0150] [Chemistry 8]

[0151]

[0152] <Comparative test and evaluation>

[0153] The 11 oil-water separation filters obtained in Examples 1 to 8 and Comparative Examples 1 to 4 were separately installed in Figure 5 The oil-water separation test device 100 shown in FIG. Figure 1The symbols of the oil-water separation test device 100 are represented by adding 100 to the symbols of the elements corresponding to the oil-water separation test device 100. In the oil-water separation test device 100, as the emulsified oil, 0.25 g of HISCREW OIL NEXT, a screw compressor oil produced by Hitachi, was mixed with 5 liters of ion exchange water at 9000 rpm for 3 minutes, and an emulsified oil (liquid containing water and oil) with a turbid oil concentration of 50 ppm was used. The emulsified oil was supplied to the liquid inlet 112 and filtered by the oil-water separation filter 113. The filtrate 114 passed through the oil-water separation filter 113 and stored in the water storage part (flask with a branch) 117 was collected, and the "(a) oil concentration of the filtrate", "(b) turbidity of the filtrate", and "(c) passage time of the filtrate" were evaluated by the following method. The results are shown in the above Table 3. It should be noted that the oil-water separation filter 113 is supported by a metal sieve plate (mesh plate) 120. In addition, when filtering the emulsified oil, the 12 oil-water separation filters obtained in Examples 1 to 8 and Comparative Examples 1 to 4 were adjusted to a predetermined vacuum degree (-10 kPa) by a suction pump (not shown) connected to the branch pipe 121 of the flask 117, and the pressure in the flask was reduced to perform suction filtration on the oil-water separation filter 113. Reference numeral 122 is a vacuum gauge.

[0154] (a) Oil concentration of filtrate

[0155] The oil concentration of the filtrate was determined by measuring the residual oil content of the filtrate using an oil content meter (manufactured by Horiba, Ltd., OCMA-555), and the oil concentration of the filtrate was obtained. The detection limit of the oil content meter varies depending on the type of oil, but is 1 ppm for the emulsified oil used. It should be noted that in the "oil concentration of the filtrate" in Table 3 and Table 4 described later, "<1" indicates that the oil content is below the detection limit of the oil content meter.

[0156] (b) Turbidity of the filtrate

[0157] The turbidity of the filtrate was measured using a Lacom Tester turbidity meter TN-100 (manufactured by Aswan Co., Ltd.) The smaller the turbidity, the better the oil-water separation property, and 1.5 or less is an acceptable level.

[0158] (c) Filtrate passage time

[0159] The measurement of the passage time of the filtrate is to measure the time from when the suction pump starts to work until the total amount of the emulsified oil passes through the oil-water separation filter 113 and reaches the water storage part (flask with a branch) 117.

[0160] It is clear from Table 3 that the oil-water separation filter of Comparative Example 1 is prepared by the comparative synthesis example 1 of the oxide (titanium dioxide) particle containing the average particle diameter of 230nm to form a water-repellent and oil-repellent film liquid composition, nonwoven fabric is immersed in the liquid composition, and deliquescence, drying and making, therefore the average particle diameter of oxide particles is too large, it is difficult to use the carboxyl-containing material as the adhesive component etc. oxide particles are bonded to the fiber surface of nonwoven fabric. As a result, the oil concentration of the filtrate is less than the detection limit of 1ppm, the turbidity of the filtrate is high, being 4.0, and the passing time of the filtrate is longer, being 96 seconds, and the filtration efficiency is poor.

[0161] The oil-water separation filter of Comparative Example 2 has poor oil repellency due to the fact that the fluorine-based functional group component (A) in the water- and oil-repellent membrane is too little, at 0.005 mass %. Therefore, the passage time of the filtrate is short, at 40 seconds, the oil concentration of the filtrate is high, at 7.0 ppm, and the turbidity of the filtrate is also high, at 2.0.

[0162] The oil-water separation filter of Comparative Example 3 has a high air permeability of 15.0 ml / cm 2 / second, so the passage time of the filtrate is short, which is 35 seconds, but since the fluorine-based functional group component (A) in the water-repellent and oil-repellent membrane is excessive, which is 17.8% by mass, the adhesion of the water-repellent and oil-repellent membrane to the non-woven fabric is poor, the oil concentration of the filtrate is very high, which is 42.0ppm, and the turbidity of the filtrate is also very high, which is 5.0.

[0163] The air permeability of the oil-water separation filter of Comparative Example 4 is appropriate, which is 2.1 ml / cm 2 / second, the oil concentration of the filtrate was less than the detection limit of 1 ppm, and the turbidity of the filtrate was 0.5. On the other hand, since the fluorine compound having the perfluoroamine structure of formula (29) was used, the structure of the fluorine compound of the oil-water separation filter of Comparative Example 4 was rigid, and the water repellency was easily strong. Therefore, compared with the oil-water separation filters containing the fluorine compound having the perfluoroether structure of Examples 1 to 8, the passage time of the filtrate was longer, which was 120 seconds, and the filtration efficiency was poor.

[0164] In contrast, the oil-water separation filters of Examples 1 to 8 satisfy the requirements of the first aspect of the present invention, so the oil concentration of the filtrate is less than the detection limit of 1 ppm, or 1.3 ppm (Example 7) or 1.4 ppm (Example 8), the turbidity of the filtrate is less than 0.5, or 1.1 (Example 7) or 1.2 (Example 8), and the passage time of the filtrate is 33 seconds to 95 seconds, and the filtration efficiency is good. The oil concentration of the filtrate in Example 8 is 1.4 ppm and the turbidity of the filtrate is 1.2 because the air permeability of the oil-water separation filter is relatively large, which is 13.1 ml / cm 2 / Seconds sake.

[0165] Industrial Applicability

[0166] The oil-water separation filter of the present invention can be used in fields where it is necessary to separate oil from emulsified oil or water-soluble oil and recover water.

[0167] Explanation of symbols

[0168] 13, 23 Oil-water separation filter

[0169] 20 Non-woven fabric

[0170] 20a Non-woven fabric side

[0171] 20b The other side of the non-woven fabric

[0172] 20c Non-woven fabric fibers

[0173] 20d non-woven fabric pores

[0174] 21 Water and oil repellent film

[0175] 21a Fluorine-containing oxide particles

[0176] 21b Carboxyl-containing substances, etc.

[0177] 22 Oil particles.

Claims

1. An oil-water separation filter comprising a nonwoven fabric having a plurality of pores formed between fibers, wherein the plurality of pores penetrate between a side through which a liquid containing water and oil flows in and another side opposite to the side through which the liquid flows out, wherein the oil-water separation filter is characterized in that: A water- and oil-repellent film is formed on the fiber surface of the nonwoven fabric. The water- and oil-repellent film comprises oxide particles (B) having an average particle size of 2 nm to 90 nm and a substance (C) containing a carboxyl group and / or an acetyl group, wherein the oxide particles (B) are combined with a fluorine-based functional group component (A) having a perfluoroether structure represented by the following general formula (1) or formula (2), The oxide particles (B) are oxide particles of one kind selected from the group consisting of Si, Al, Mg, Ca, Ti, Zn and Zr, The fluorine-based functional group component (A) is contained in the water- and oil-repellent film at a ratio of 0.3% to 5.0% by mass, The fluorine-based functional group component (A) and the oxide particles (B) are contained in the water- and oil-repellent film in a total amount of 30% to 90% by mass, and The mass ratio (A / B) of the fluorine-based functional group component (A) to the oxide particles (B) is in the range of 0.01 to 0.2, The air permeability of the oil-water separation filter is 0.05 ml / cm 2 / sec~14ml / cm 2 / Second; [Chemistry 1] C p F 2p+1 -O-C q F 2q -O-C r F 2r -X-Y (1) C p F 2p+1 -O-C q F 2q -X-Y (2) In the above formula (1) and formula (2), p, q and r are each the same or different integers of 1 to 6, and the perfluoroether group may be linear or branched. In addition, in the above formula (1) and formula (2), X is a hydrocarbon group having 2 to 10 carbon atoms and may contain one or more bonds selected from ether bonds, CO-NH bonds, O-CO-NH bonds and sulfonamide bonds. Furthermore, in the above formula (1) and formula (2), Y is a main component of a hydrolyzate of silane or a silica sol-gel.

2. The oil-water separation filter according to claim 1, wherein: The carboxyl and / or acetyl group-containing substance (C) is a polyolefin-based aqueous dispersion having a carboxyl group, a self-emulsified liquid of an ethylene-vinyl acetate copolymer, or a self-emulsified liquid of an ethylene-vinyl acetate-acrylic acid copolymer.

3. The oil-water separation filter according to claim 1, wherein: The nonwoven fabric is composed of a single layer or a laminate of multiple layers.

4. The oil-water separation filter according to claim 1 or 3, wherein: The fibers constituting the nonwoven fabric are one or more fibers selected from the group consisting of polyethylene terephthalate (PET), polypropylene (PP), polytetrafluoroethylene (PTFE), glass, alumina, carbon, cellulose, pulp, nylon and metal.

5. A method for manufacturing an oil-water separation filter, comprising: A step of preparing a water- and oil-repellent film-forming liquid composition by mixing an aqueous dispersion of fluorine oxide particles, a substance (C) containing a carboxyl group and / or an acetyl group, and a solvent containing 40% by mass or less of an alcohol having 1 to 4 carbon atoms, which is a mixture of water and an alcohol having 1 to 4 carbon atoms; a step of immersing a nonwoven fabric in a diluted solution of the water- and oil-repellent film-forming liquid composition, and a step of removing the diluted solution from the immersed nonwoven fabric and drying the nonwoven fabric, In the step of preparing the liquid composition for forming a water- and oil-repellent film, The fluorine-containing oxide particles are oxide particles (B) having an average particle size of 2 nm to 90 nm and bonded with a fluorine-based functional group component (A) having a perfluoroether structure represented by the following general formula (1) or formula (2), wherein the oxide particles (B) are oxide particles of one selected from Si, Al, Mg, Ca, Ti, Zn and Zr. The carboxyl and / or acetyl-containing substance (C) is a polyolefin-based aqueous dispersion having a carboxyl group, a self-emulsified liquid of an ethylene-vinyl acetate copolymer, or a self-emulsified liquid of an ethylene-vinyl acetate-acrylic acid copolymer, The fluorine-based functional group component (A) is contained in the formed water- and oil-repellent film at a ratio of 0.3% to 5.0% by mass, and the fluorine-based functional group component (A) and the oxide particles (B) are contained in the water- and oil-repellent film at a total ratio of 30% to 90% by mass, The mass ratio (A / B) of the fluorine-based functional group component (A) to the oxide particles (B) is in the range of 0.01 to 0.2, [Chemistry 2] C p F 2p+1 -O-C q F 2q -O-C r F 2r -X-Y (1) C p F 2p+1 -O-C q F 2q -X-Y (2) In the above formula (1) and formula (2), p, q and r are each the same or different integers of 1 to 6, and the perfluoroether group may be linear or branched. In addition, in the above formula (1) and formula (2), X is a hydrocarbon group having 2 to 10 carbon atoms and may contain one or more bonds selected from ether bonds, CO-NH bonds, O-CO-NH bonds and sulfonamide bonds. Furthermore, in the above formula (1) and formula (2), Y is a main component of a hydrolyzate of silane or a silica sol-gel.

6. The method for manufacturing an oil-water separation filter according to claim 5, wherein: The aqueous dispersion of the fluorine-containing oxide particles is prepared by adding a fluorine-based compound to an aqueous dispersion of the oxide particles to obtain a mixed solution, and adding a mixed catalyst to the mixed solution.

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