Non-woven fabric for filtration and preparation method thereof

Abstract

The invention provides a non-woven fabric for filtration and a preparation method thereof, and belongs to the technical field of textiles. The non-woven fabric for filtering comprises a flat net fiber layer, a first inclined net fiber layer and shaped glass fiber gridding cloth located between the flat net fiber layer and the first inclined net fiber layer. Wherein the materials of the flat net fiber layer and the first inclined net fiber layer are respectively and independently selected from polyethylene glycol terephthalate or polytrimethylene terephthalate; the shaped glass fiber gridding cloth is obtained by shaping and fixing the glass fiber gridding cloth through a shaping agent.

Description

Technical Field

[0001] The invention belongs to the technical field of weaving and manufacturing textile products, and more specifically relates to a nonwoven fabric for filtering and a preparation method thereof. Background Art

[0002] Existing conventional short-fiber nonwoven fabrics for filtration are prone to rupture, deformation and other problems when impacted, thereby affecting the filtration efficiency and effect. Summary of the invention

[0003] In view of the above technical problems, the present invention provides a nonwoven fabric for filtration and a preparation method thereof, in order to solve the above technical problems. In this regard, the technical solution provided by the present invention is as follows.

[0004] As a first aspect of the present invention, a nonwoven fabric for filtration is provided, comprising: a flat mesh fiber layer, a first oblique mesh fiber layer, and a shaped glass fiber mesh cloth located between the flat mesh fiber layer and the first oblique mesh fiber layer; wherein the materials of the flat mesh fiber layer and the first oblique mesh fiber layer are independently selected from polyethylene terephthalate (PET) or polytrimethylene terephthalate (PTT); and the shaped glass fiber mesh cloth is obtained by fixing the glass fiber mesh cloth with a setting agent.

[0005] As a second aspect of the present invention, a method for preparing a non-woven fabric for filtration is provided, comprising: subjecting a flat mesh fiber layer raw material and a first oblique mesh fiber layer raw material to crystallization drying, metered spinning, cooling and drawing, and filament laying to obtain a flat mesh fiber layer and a first oblique mesh fiber layer; adding a shaped glass fiber mesh cloth between the flat mesh fiber layer and the first oblique mesh fiber layer, fixing the glass fiber mesh cloth through needle punching and hot rolling to obtain a non-woven fabric for filtration; wherein the flat mesh fiber layer raw material and the first oblique mesh fiber layer raw material are each independently selected from polyethylene terephthalate (PET) or polypropylene terephthalate (PTT); and the shaped glass fiber mesh cloth is obtained by fixing the glass fiber mesh cloth with a setting agent.

[0006] Based on the above technical solution, the present invention provides a non-woven fabric for filtration and a preparation method thereof, which has at least the following beneficial effects:

[0007] (1) In the embodiment of the present invention, a shaped glass fiber mesh cloth is introduced between the flat mesh fiber layer and the first oblique mesh fiber layer, which can solve the problem that the current non-woven fabric has weak impact resistance and is easy to deform. The combination of the flat mesh fiber layer and the first oblique mesh fiber layer can, on the one hand, enhance the impact resistance of the non-woven fabric, and on the other hand, improve the production quality of the non-woven fabric and improve the uniformity of fiber distribution in the non-woven fabric.

[0008] (2) The flat mesh fiber layer and the inclined mesh fiber layer are made of the same material, so that the prepared non-woven fabric has higher strength and lower production cost; by combining PET and PTT materials, the prepared non-woven fabric has higher filtration efficiency and good tensile strength and elasticity.

[0009] (3) In the embodiments of the present invention, the preparation process of the non-woven fabric for filtration provided by the present invention is relatively simple and can be produced continuously, thus ensuring the consistency of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic diagram of the structure of the nonwoven fabric for filtration in an embodiment of the present invention;

[0011] Figure 2 A schematic diagram of the structure of a nonwoven fabric for filtration in another embodiment of the present invention;

[0012] Figure 3 This is a schematic diagram of the process for preparing a nonwoven fabric for filtration in Example 1 of the present invention;

[0013] Figure 4 This is a schematic diagram of the web-forming structure of the nonwoven fabric for filtration in Example 1 of the present invention;

[0014] Figure 5 Schematic diagram of the web-forming structure of the nonwoven fabric for filtration in Example 2 of the present invention. DETAILED DESCRIPTION

[0015] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0016] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The term "comprising" used herein indicates the existence of features, steps, operations, but does not exclude the existence or addition of one or more other features.

[0017] In the case of using expressions such as "at least one of A, B, and C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.). In the case of using expressions such as "at least one of A, B, or C, etc.", it should generally be interpreted in accordance with the meaning of the expression generally understood by those skilled in the art (for example, "a system having at least one of A, B, or C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0018] In view of the problem that conventional short-fiber nonwoven fabrics for filtration are prone to rupture and deformation when impacted, thus affecting the filtration efficiency and effect, the present invention provides a new nonwoven fabric for filtration, which introduces a shaped glass fiber mesh cloth to enhance the ability of the nonwoven fabric for filtration to resist impact and reduce deformation. By combining a flat mesh fiber layer, a shaped glass fiber mesh cloth and an inclined mesh fiber layer, the strength, uniformity and quality of the nonwoven fabric can be further improved. Furthermore, by modifying the fibers during the spinning stage of the nonwoven fabric, the prepared nonwoven fabric can have antibacterial properties, and by modifying the nonwoven fabric after needle-punching fixation and hot rolling treatment, the prepared nonwoven fabric can have anti-fouling, waterproof, flame-retardant and other properties.

[0019] Figure 1 Schematic diagram of the structure of the nonwoven fabric for filtration in an embodiment of the present invention.

[0020] Specifically, Figure 1 As shown, as a first aspect of the present invention, a non-woven fabric for filtration is provided, comprising: a flat mesh fiber layer, a first oblique mesh fiber layer, and a shaped glass fiber mesh cloth located between the flat mesh fiber layer and the first oblique mesh fiber layer; wherein the materials of the flat mesh fiber layer and the first oblique mesh fiber layer are independently selected from polyethylene terephthalate (PET) or polytrimethylene terephthalate (PTT); the shaped glass fiber mesh cloth is obtained by fixing the glass fiber mesh cloth with a setting agent.

[0021] In the embodiment of the present invention, a shaped glass fiber mesh cloth is introduced between the flat mesh fiber layer and the first oblique mesh fiber layer, which can solve the problems of weak impact resistance and easy deformation of the current non-woven fabric. The combination of the flat mesh fiber layer and the oblique mesh fiber layer can enhance the impact resistance of the non-woven fabric on the one hand, and improve the production quality of the non-woven fabric and the uniformity of the non-woven fabric fibers on the other hand.

[0022] According to an embodiment of the present invention, the glass fiber mesh cloth is formed by cross-weaving transverse glass fibers and longitudinal glass fibers, and the woven glass fiber mesh cloth is a mesh of 8-10 mm square. The pure glass fiber mesh cloth is relatively soft in texture, and is easily deformed during the process of filament laying and needle-punching fixation with the flat mesh fiber layer and the first oblique mesh fiber layer. It cannot effectively improve the impact resistance of the non-woven fabric and cannot effectively solve the problem of deformation of the non-woven fabric. In this regard, the present invention proposes to use a shaped glass fiber mesh cloth, wherein the shaped glass fiber mesh cloth is obtained by fixing the glass fiber mesh cloth with a setting agent. Furthermore, the setting agent includes: epoxy resin and amine curing agent, and the amine curing agent is selected from one or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, and diethylaminopropylamine, and can be cured at room temperature. By shaping the glass fiber mesh cloth with epoxy resin and amine curing agent, it is beneficial to improve the strength of the glass fiber mesh cloth, and make the glass fiber mesh cloth have a certain deformation resistance to prevent deformation during the reinforcement process. It can solve the problems of deformation, uneven distribution of glass fibers and bending that are prone to occur during the needle punching reinforcement stage of the current glass fiber woven mesh, and improve the impact resistance of the non-woven fabric.

[0023] According to one embodiment of the present invention, the nonwoven fabric for filtration of the present invention may include: a PET flat mesh fiber layer, a shaped glass fiber mesh cloth and a PET first oblique mesh fiber layer in sequence. Since PET has good tensile strength, the nonwoven fabric composed of such a structure and material has higher strength and lower production cost. The nonwoven fabric for filtration of the present invention may also include a PTT flat mesh fiber layer, a shaped glass fiber mesh cloth and a PTT first oblique mesh fiber layer. PTT has a good bending elastic modulus, which is conducive to forming a porous three-dimensional structure, thereby improving the filtering performance of the nonwoven fabric, but the tensile strength of the pure PTT is slightly low, and by introducing a shaped glass fiber mesh cloth, the tensile strength of the nonwoven fabric prepared only with PTT can be improved. The present invention can also prepare a nonwoven fabric including a PET flat mesh fiber layer, a shaped glass fiber mesh cloth, and a PTT first oblique mesh fiber layer, or a nonwoven fabric including a PTT flat mesh fiber layer, a shaped glass fiber mesh cloth, and a PET first oblique mesh fiber layer by combining PET and PTT. The prepared nonwoven fabric has high filtering efficiency and good tensile strength and elasticity.

[0024] According to an embodiment of the present invention, the flat mesh fiber layer is formed by laying a single layer of fibers, and the first oblique mesh fiber layer is formed by cross-laying two layers of fibers, wherein the fibers in the flat mesh fiber layer and the first oblique mesh fiber layer are filaments. By using filament fibers, the problem that the existing short filament fibers are easy to break and deform when the non-woven fabric is impacted can be solved. Further, in terms of the mass percentage of the fiber layer, the flat mesh fiber layer is 20%-80%, the first oblique mesh fiber layer is 20%-80%, and the total is 100%. For example, in terms of the mass percentage of the fiber layer, the PET flat mesh fiber layer is 20%-80%, the PTT first oblique mesh fiber layer is 20%-80%, and the total is 100%; or in terms of the mass percentage of the fiber layer, the PTT flat mesh fiber layer is 20%-80%, the PET first oblique mesh fiber layer is 20%-80%, and the total is 100%. Furthermore, the thickness of the flat mesh fiber layer is positively correlated with the mass percentage of the flat mesh fiber layer, and the thickness of the first oblique mesh fiber layer is positively correlated with the mass percentage of the first oblique mesh fiber layer. In other words, the higher the mass percentage of the flat mesh fiber layer in the nonwoven fabric, the greater the proportion of the flat mesh fiber layer to the total thickness of the nonwoven fabric; the higher the mass percentage of the first oblique mesh fiber layer in the nonwoven fabric, the greater the proportion of the first oblique mesh fiber layer to the total thickness of the nonwoven fabric. If the mass percentage of the PTT flat mesh fiber layer or the PTT first oblique mesh fiber layer is higher, the obtained nonwoven fabric has higher fluffiness and better filtration performance; if the mass percentage of the PET flat mesh fiber layer or the PET first oblique mesh fiber layer is higher, the obtained nonwoven fabric has higher strength. More specifically, for example, in terms of the mass percentage of the fiber layer, the PET flat mesh fiber layer is 20%, the PTT first oblique mesh fiber layer is 80%, and the total is 100%, wherein the thickness of the PTT first oblique mesh fiber layer is greater, and the fiber distribution in the obtained nonwoven fabric is more uniform, the quality is better, and the air permeability and filtration performance are better. For example: the PET flat mesh fiber layer is 80%, the PTT first oblique mesh fiber layer is 20%, and the total is 100%. Among them, the mass percentage of the PET flat mesh fiber layer is higher, the thickness of the PET flat mesh fiber layer is greater, and the obtained non-woven fabric has higher tensile strength and stronger durability. For another example: the PET flat mesh fiber layer is 50%, the PTT first oblique mesh fiber layer is 50%, and the total is 100%. The obtained non-woven fabric has good filtering performance and excellent strength.

[0025] According to an embodiment of the present invention, the non-woven fabric of the present invention may further include: antibacterial substances and / or antifouling additives. The antibacterial substances are antibacterial agents with bactericidal functions, such as Ag ions, Cu ions, etc., and the non-woven fabric has antibacterial properties by adding antibacterial substances. The antifouling additives are compounds with waterproof and oil-proof functions, such as fluorine-containing monomers. Furthermore, the antibacterial substances and / or antifouling additives may be distributed in each fiber layer of the non-woven fabric, or may be distributed only in the flat mesh fiber layer or the first oblique mesh fiber layer.

[0026] Figure 2 It is a schematic diagram of the structure of a nonwoven fabric for filtration in another embodiment of the present invention.

[0027] According to another embodiment of the present invention, Figure 2 As shown, the nonwoven fabric for filtration may also include: a second oblique mesh fiber layer, the material of the second oblique mesh fiber layer is the same as that of the first oblique mesh fiber layer, and the second oblique mesh fiber layer is arranged on one side of the first oblique mesh fiber layer close to the shaped glass fiber mesh cloth.

[0028] In the above-mentioned embodiment of the present invention, a structure of two oblique mesh fiber layers, a glass fiber mesh cloth and a flat mesh fiber layer is adopted, and the fiber distribution in the obtained non-woven fabric is more uniform and the strength is higher.

[0029] Specifically, the nonwoven fabric for filtration in another embodiment includes: a flat mesh fiber layer, a shaped glass fiber mesh cloth, a second oblique mesh fiber layer, and a first oblique mesh fiber layer. More specifically, the nonwoven fabric may include: a PET flat mesh fiber layer, a shaped glass fiber mesh cloth, a PET second oblique mesh fiber layer, and a PET first oblique mesh fiber layer. Since PET has good tensile strength, the nonwoven fabric with such a structure and composed entirely of PET materials also has higher strength and lower production cost. The nonwoven fabric for filtration in another embodiment may include: a PET flat mesh fiber layer, a shaped glass fiber mesh cloth, a PTT second oblique mesh fiber layer, and a PTT first oblique mesh fiber layer; or a PTT flat mesh fiber layer, a shaped glass fiber mesh cloth, a PET second oblique mesh fiber layer, and a PET first oblique mesh fiber layer. By combining PET and PTT materials, the obtained nonwoven fabric has good filtration performance and good tensile strength, and can resist impact crushing and deformation.

[0030] According to an embodiment of the present invention, in another embodiment of the nonwoven fabric for filtration, the first oblique mesh fiber layer and the second oblique mesh fiber layer are also formed by cross-laying two layers of fibers, the flat mesh fiber layer is also formed by laying a single layer of fibers, and the glass fiber mesh cloth is also formed by cross-weaving transverse glass fibers and longitudinal glass fibers, and the woven glass fiber mesh cloth is a mesh of 8-10 mm square. The woven glass fiber mesh cloth is fixed by a setting agent to form a fixed glass fiber mesh cloth, and the setting agent includes epoxy resin and amine curing agent, and the amine curing agent is as defined in the above embodiment. Furthermore, the fibers in the flat mesh fiber layer, the first oblique mesh fiber layer and the second oblique mesh fiber layer in the nonwoven fabric are all filaments, which can solve the problem that the existing short filament fibers are easily broken and deformed when the nonwoven fabric is prepared by impact. Further, in another embodiment of the nonwoven fabric for filtration, in terms of the mass percentage of the fiber layer, the flat mesh fiber layer is 20%-80%, the oblique mesh fiber layer is 20%-80%, and the total is 100%, wherein the oblique mesh fiber layer is 20%-80%, which means that the total amount of the first oblique mesh fiber layer and the second oblique mesh fiber layer is 20%-80%, and specifically, the mass percentage between the first oblique mesh fiber layer and the second oblique mesh fiber layer can be flexibly adjusted as needed. For example: in terms of the mass percentage of the fiber layer, the PET flat mesh fiber layer is 20%-80%, the PTT oblique mesh fiber layer (including the first oblique mesh fiber layer and the second oblique mesh fiber layer) is 20%-80%, and the total is 100%; or the PTT flat mesh fiber layer is 20%-80%, the PET oblique mesh fiber layer (including the first oblique mesh fiber layer and the second oblique mesh fiber layer) is 20%-80%, and the total is 100%. Furthermore, the thickness of the flat mesh fiber layer is positively correlated with the mass percentage of the flat mesh fiber layer, the thickness of the first oblique mesh fiber layer is positively correlated with the mass percentage of the first oblique mesh fiber layer, and the thickness of the second oblique mesh fiber layer is positively correlated with the mass percentage of the second oblique mesh fiber layer. In other words, the higher the mass percentage of the flat mesh fiber layer in the non-woven fabric, the greater the proportion of the flat mesh fiber layer to the total thickness of the non-woven fabric; the higher the mass percentage of the first oblique mesh fiber layer in the non-woven fabric, the greater the proportion of the first oblique mesh fiber layer to the total thickness of the non-woven fabric; the higher the mass percentage of the second oblique mesh fiber layer in the non-woven fabric, the greater the proportion of the second oblique mesh fiber layer to the total thickness of the non-woven fabric. If the mass percentage of the PTT flat mesh fiber layer or the PTT oblique mesh fiber layer (including the first oblique mesh fiber layer and the second oblique mesh fiber layer) is higher, the obtained non-woven fabric has higher fluffiness and better filtering performance; if the mass percentage of the PET flat mesh fiber layer or the PET oblique mesh fiber layer (including the first oblique mesh fiber layer and the second oblique mesh fiber layer) is higher, the obtained non-woven fabric has higher strength.More specifically, for example, in terms of the mass percentage of the fiber layer, the PET flat mesh fiber layer is 60%, the PTT first oblique mesh fiber layer is 20%, and the PTT second oblique mesh fiber layer is 20%, totaling 100%; or the PTT flat mesh fiber layer is 30%, the PET first oblique mesh fiber layer is 35%, and the PET second oblique mesh fiber layer is 35%, totaling 100%; wherein the PET flat mesh fiber layer or the PET oblique mesh fiber layer has a higher proportion, a greater thickness, and the strength of the fibers in the obtained nonwoven fabric is greater. For another example: the PTT flat mesh fiber layer is 60%, the PET first oblique mesh fiber layer is 20%, and the PET second oblique mesh fiber layer is 20%, totaling 100%; or the PET flat mesh fiber layer is 30%, the PTT first oblique mesh fiber layer is 35%, and the PTT second oblique mesh fiber layer is 35%, totaling 100%; wherein the PTT flat mesh layer or the PTT oblique mesh fiber layer has a higher mass percentage, and its thickness is also higher, and the obtained nonwoven fabric has a higher fluffiness and better filtering performance.

[0031] According to an embodiment of the present invention, the nonwoven fabric for filtration in another embodiment may further include: antibacterial substances and / or antifouling additives, and the antibacterial substances and / or antifouling additives in another embodiment are the same as those described above and will not be described in detail herein. Further, the antibacterial substances and / or antifouling additives may be distributed in at least one of the flat mesh fiber layer, the first oblique mesh fiber layer, and the second oblique mesh fiber layer.

[0032] As a second aspect of the present invention, a method for preparing a non-woven fabric for filtration is provided, comprising: subjecting a flat mesh fiber layer raw material and a first oblique mesh fiber layer raw material to crystallization drying, metered spinning, cooling drawing, and filament laying to obtain a flat mesh fiber layer and a first oblique mesh fiber layer; adding a shaped glass fiber mesh cloth between the flat mesh fiber layer and the first oblique mesh fiber layer, fixing the glass fiber mesh cloth through needle punching and hot rolling to obtain a non-woven fabric for filtration; wherein the flat mesh fiber layer raw material and the first oblique mesh fiber layer raw material are each independently selected from polyethylene terephthalate or polytrimethylene terephthalate; and the shaped glass fiber mesh cloth is obtained by fixing the glass fiber mesh cloth with a setting agent.

[0033] In the embodiments of the present invention, the preparation process of the nonwoven fabric for filtration provided by the present invention is relatively simple and can be produced continuously, thus ensuring the consistency of the product.

[0034] According to an embodiment of the present invention, the shaped glass fiber mesh cloth can be obtained by the following method: spraying a solution containing a shaping agent on the woven glass fiber mesh cloth, or immersing the woven glass fiber mesh cloth in a solution containing a shaping agent, wherein the shaping agent includes an epoxy resin and an amine curing agent.

[0035] According to an embodiment of the present invention, the flat mesh fiber layer raw material and the first inclined mesh fiber layer raw material are crystallized and dried separately, comprising: passing the flat mesh fiber layer raw material and the first inclined mesh fiber layer raw material through a fluidized bed crystallization and a drying tower for crystallization and drying. By passing the flat mesh fiber layer raw material and the first inclined mesh fiber layer raw material through a fluidized bed crystallization and a drying tower respectively, the moisture in the flat mesh fiber layer raw material and the first inclined mesh fiber layer raw material can be fully dried.

[0036] Specifically, the steps of crystallization and drying of PET and PTT slice raw materials include: adding PET slice raw materials to a wet material bin, removing moisture from the PET slice raw materials through a boiling crystallization bed and a drying tower, wherein the PET crystallization temperature is 180±5°C and the drying temperature is 170±5°C. Adding PTT slice raw materials to a wet material bin, removing moisture from the PTT slice raw materials through a boiling crystallization bed and a drying tower, wherein the PTT crystallization temperature is 100±10°C and the drying temperature is 130±5°C.

[0037] According to an embodiment of the present invention, metered spinning includes: conveying the dried flat mesh fiber layer raw material and the first inclined mesh fiber layer raw material to a screw extruder, filtering through a melt filter to obtain a flat mesh fiber layer melt and a first inclined mesh fiber layer melt; the flat mesh fiber layer melt and the first inclined mesh fiber layer melt are metered by a metering pump, spun by a spinning assembly, and cooled and stretched to obtain a flat mesh layer fiber bundle and a first inclined mesh layer fiber bundle.

[0038] Specifically, continuing to take PET and PTT as examples, the crystallized and dried PET slice raw materials and PTT slice raw materials are transported to a screw extruder, and filtered through a melt filter to obtain PET melt and PTT melt. Subsequently, the PET melt and PTT melt are metered by a metering pump, spun by a spinning assembly, and cooled and stretched to obtain PET fiber bundles and PTT fiber bundles.

[0039] According to an embodiment of the present invention, the filament laying includes: respectively dispersing the flat mesh layer fiber bundle and the first oblique mesh layer fiber bundle into monofilaments and evenly spreading them on a web-forming machine to form a flat mesh fiber layer and a first oblique mesh fiber layer. For example: according to the flat mesh and oblique mesh laying methods, the PET fiber bundle and the PTT fiber bundle are respectively filament laid to obtain a PET flat mesh fiber layer or a PET first oblique mesh fiber layer; and a PTT flat mesh fiber layer or a PTT first oblique mesh fiber layer.

[0040] According to an embodiment of the present invention, a shaped glass fiber mesh is added between the flat mesh fiber layer and the first oblique mesh fiber layer, and the shaped glass fiber mesh is used to increase the lateral and longitudinal deformation resistance of the non-woven fabric for filtration, thereby improving the impact resistance of the non-woven fabric. For example, a shaped glass fiber mesh is added between the PTT flat mesh fiber layer and the first oblique mesh fiber layer of PET; or a shaped glass fiber mesh is added between the PET flat mesh fiber layer and the first oblique mesh fiber layer of PTT.

[0041] According to an embodiment of the present invention, acupuncture fixation includes two steps of reinforcement: pre-acupuncture and main acupuncture, wherein the density of pre-acupuncture and main acupuncture is 21-36 needles / cm 2 The flat mesh fiber layer, the shaped glass fiber mesh cloth and the first oblique mesh fiber layer are successively reinforced by pre-needling and main needling to form a nonwoven fabric with a certain strength.

[0042] According to an embodiment of the present invention, the nonwoven fabric is subjected to hot rolling treatment to obtain nonwoven fabrics for filtering of different thicknesses. The thickness of the nonwoven fabric for filtering is controlled by controlling the temperature of the hot rolling treatment. The higher the temperature of the hot rolling treatment and the greater the pressure, the thinner the nonwoven fabric formed, and vice versa. The hot rolling treatment temperature is 200-240°C and the pressure is 45-55 bar.

[0043] According to another embodiment of the present invention, the method for preparing a non-woven fabric for filtration also includes: the raw material of the second oblique mesh fiber layer is subjected to crystallization drying, metered spinning, cooling and stretching, and filament laying to obtain a second oblique mesh fiber layer; the second oblique mesh fiber layer is arranged on the side of the first oblique mesh fiber layer close to the shaped glass fiber mesh cloth, and is subjected to needle punching, fixation, and hot rolling to obtain a non-woven fabric for filtration; wherein the raw material of the second oblique mesh fiber layer is the same as the raw material of the first oblique mesh fiber layer.

[0044] According to an embodiment of the present invention, before metered spinning, the method for preparing a nonwoven fabric for filtration further includes: adding antibacterial substances. After drying the flat mesh fiber layer raw material and the first oblique mesh fiber layer raw material, antibacterial substances are added to at least one of the flat mesh fiber layer raw material and the first oblique mesh fiber layer raw material, respectively, and mixed. After mixing evenly, metered spinning and other operations are performed to obtain a nonwoven fabric for filtration with antibacterial properties. Alternatively, after drying the flat mesh fiber layer raw material, the first oblique mesh fiber layer raw material, and the second oblique mesh fiber layer raw material, antibacterial substances are added to at least one of the flat mesh fiber layer raw material, the first oblique mesh fiber layer raw material, and the second oblique mesh fiber layer raw material, and mixed. After mixing evenly, metered spinning and other operations are performed to obtain a nonwoven fabric for filtration with antibacterial properties, wherein the antibacterial substances are metal ions, such as silver ions.

[0045] According to an embodiment of the present invention, after the hot rolling treatment, the method for preparing a non-woven fabric for filtration further includes: immersing the non-woven fabric in a glue solution containing an anti-fouling additive, and obtaining the non-woven fabric for filtration after drying. The preparation of the glue solution containing the anti-fouling additive includes: adding an initiator, a curing agent, and an anti-fouling additive to an acrylic emulsion, heating the temperature to 70-90°C, and keeping the temperature for 2-3 hours. Furthermore, the anti-fouling additive is a fluorine-containing monomer, for example, at least one selected from perfluoroacrylate, perfluorohexylethyl acrylate, and perfluorooctylethyl acrylate, and the amount of the anti-fouling additive (i.e., the fluorine-containing monomer) added is 1wt-5wt%. The mass ratio of acrylic emulsion to curing agent is 25-20:1; the initiator is selected from azobisisobutylamidine hydrochloride; the curing agent is a peroxide compound, such as at least one selected from benzoyl peroxide-N, N-dimethylaniline, ammonium persulfate-sodium bisulfite, potassium persulfate-sodium bisulfite, hydrogen peroxide-tartaric acid, hydrogen peroxide-dangbaikuai, ammonium persulfate-ferrous sulfate, hydrogen peroxide-ferrous sulfate. Acrylic emulsion is an aqueous dispersion of butyl acrylate and styrene copolymer. Further, the configuration of the glue containing antifouling additives includes: 2000kg water, 350-400kg acrylic emulsion containing antifouling additives, and 75-100kg corn starch. The drying method includes: round mesh penetration drying, and the drying temperature is 150~220℃.

[0046] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments and drawings.

[0047] Example 1

[0048] Figure 3 This is a schematic diagram of the process for preparing nonwoven fabric for filtration in Example 1 of the present invention.

[0049] like Figure 3 As shown, the method for preparing nonwoven fabric for filtration includes: step 1 to step 12.

[0050] Step 1: Loading: Add PET chips and PTT chips into the wet material bin respectively.

[0051] Step 2: Crystallization and drying. The wet PET chips and wet PTT chips are transported to a fluidized crystallization bed and a drying tower for crystallization and drying, respectively. The crystallization temperature of PTT is 100±10°C, the drying temperature is 130±5°C, the crystallization temperature of PET is 180±5°C, the drying temperature is 170±5°C, and the drying time is 6 hours.

[0052] Step 3: Adding metal ion antibacterial substances. The dried PET slice raw materials and PTT slice raw materials are respectively sent to the screw extruder for melting, and the metal ion antibacterial substances are added for blending to obtain PET melt and PTT melt with antibacterial function.

[0053] Step 4-Step 5: metering spinning and cooling and stretching. After the PET melt and the PTT melt are metered by a metering pump, spun by a spinning assembly, and cooled and stretched, a PET fiber bundle and a PTT fiber bundle are obtained, wherein the speed of the PTT metering pump is 20 r / min, the speed of the PET metering pump is 18 r / min, and the total stretching pressure is 2.3 bar.

[0054] Step 6: Spread the wires and lay the net. Figure 4 In the web-forming method shown in the figure, the PET fiber bundle and the PTT fiber bundle are respectively laid to obtain a PET flat web fiber layer and a PTT first oblique web fiber layer, wherein the swinging frequency is 170 times / min, the web-forming speed is 17m / min, and the gram weight of the obtained PET flat web fiber layer is 57.59g / m 2 The weight of the first oblique fiber layer of PTT is 54.17g / m 2 , where in terms of fiber layer mass percentage, the PET flat mesh fiber layer is 51.5%, the PTT first oblique mesh fiber layer is 48.5%, and the total is 100%.

[0055] Step 7: Add the shaped glass fiber mesh cloth. The transverse fibers and the longitudinal fibers are woven into a 10 mm square glass fiber mesh cloth. A solution containing a shaping agent is sprayed on the surface of the glass fiber mesh cloth, and after drying, a shaped glass fiber mesh cloth is obtained, wherein the gram weight of the glass fiber mesh cloth is 16 g / cm 2 .

[0056] Step 8: Needle Punch Reinforcement. The PET flat mesh fiber layer, the shaped glass fiber mesh cloth, and the PTT first oblique mesh fiber layer are reinforced by two processes: pre-needle punching and main needling to obtain a nonwoven fabric with a certain strength. The density of the pre-needle punching is 24 needles / cm 2 The pre-needling depth is 9 mm, and the main needling density is 31 needles / cm 2 , the pre-needle depth is 7mm.

[0057] Step 9: Hot rolling treatment: The nonwoven fabric is subjected to hot rolling treatment, with the roller temperature being 200°C and the pressure on the east and west sides being 50 bar.

[0058] Step 10: Dipping in glue: The nonwoven fabric after hot rolling treatment is dipped in glue solution of antifouling additive to obtain a wet nonwoven fabric with waterproof and antifouling properties.

[0059] Step 11: Post-treatment: The wet nonwoven fabric is dried to obtain a dry nonwoven fabric for filtration, wherein the drying method is a rotary mesh penetration drying at a drying temperature of 220°C.

[0060] Step 12: Cut and roll. The weight of the finished nonwoven fabric for filtration is 146 g / m2 , thickness is 0.90mm.

[0061] Furthermore, the performance of the nonwoven fabric for filtration of Example 1 was tested, and the specific test results are shown in Table 1.

[0062] Test method for thermal dimensional stability: Cut the non-woven fabric for filtration to be tested, hang a 4kg weight from it, and keep it at 200℃ for 15 minutes to determine the thermal dimensional stability.

[0063] Table 1

[0064]

[0065] Example 2

[0066] Example 2 The same method as Example 1 is used to prepare a nonwoven fabric for filtration, except that the structure of the nonwoven fabric includes: a PTT flat mesh fiber layer, a shaped glass fiber mesh cloth, and two PET oblique mesh fiber layers. The specific structure is as follows: Figure 2 As shown, the specific preparation steps are as follows: step 1 to step 12.

[0067] Step 1: Loading: Add PET chips (for forming the oblique web fiber layer) and PTT chips (for forming the flat web fiber layer) into the wet material bin.

[0068] Step 2: Crystallization and drying. The wet PET chips and wet PTT chips are transported to a fluidized crystallization bed and a drying tower for crystallization and drying, respectively. The crystallization temperature of PTT is 100±10°C, the drying temperature is 130±5°C, the crystallization temperature of PET is 180±5°C, the drying temperature is 170±5°C, and the drying time is 6 hours.

[0069] Step 3: Adding metal ion antibacterial substances. The dried PET slice raw materials and PTT slice raw materials are respectively sent to the screw extruder for melting, and the metal ion antibacterial substances are added for blending to obtain PET melt and PTT melt with antibacterial function.

[0070] Step 4-Step 5: metering spinning and cooling and drawing. After the PET melt and the PTT melt are metered by a metering pump, spun by a spinning assembly, and cooled and drawn, a PET fiber bundle and a PTT fiber bundle are obtained, wherein the speed of the PTT metering pump is 15 r / min, the speed of the PET metering pump is 20 r / min, and the total drawing pressure is 2.4 bar.

[0071] Step 6: Spread the wires and lay the net. Figure 5In the web-forming method shown in the figure, the PET fiber bundle and the PTT fiber bundle are respectively laid to obtain a PTT flat web fiber layer, a PET first oblique web fiber layer and a PET second oblique web fiber layer (i.e., a PET oblique web fiber layer), wherein the swinging frequency is 170 times / min, the web-forming speed is 20m / min, and the gram weight of the obtained PTT flat web fiber layer is 72.52g / m 2 The total weight of the first PET oblique fiber layer and the second PET oblique fiber layer is 69g / m 2 The weight of each oblique mesh fiber layer is 34.5g / m 2 , where in terms of fiber layer mass percentage, the PTT flat mesh fiber layer is 51.2%, the PTT first oblique mesh fiber layer is 48.8%, and the total is 100%.

[0072] Step 7: Add the shaped glass fiber mesh cloth. The transverse fibers and the longitudinal fibers are woven into a 10 mm square glass fiber mesh cloth. A solution containing a shaping agent is sprayed on the surface of the glass fiber mesh cloth, and after drying, a shaped glass fiber mesh cloth is obtained, wherein the gram weight of the glass fiber mesh cloth is 16 g / cm 2 .

[0073] Step 8: Needle Punch Reinforcement. The PTT flat mesh fiber layer, the shaped glass fiber mesh cloth, the PET second oblique mesh fiber layer and the PET first oblique mesh fiber layer are reinforced by pre-needle punching and main needling to obtain a nonwoven fabric with a certain strength. The density of pre-needle punching is 24 needles / cm 2 The pre-needling depth is 9 mm, and the main needling density is 31 needles / cm 2 , the pre-needle depth is 7mm.

[0074] Step 9: Hot rolling treatment: The nonwoven fabric is subjected to hot rolling treatment, with the roller temperature being 200°C and the pressure on the east and west sides being 50 bar.

[0075] Step 10: Dipping in glue: The nonwoven fabric after hot rolling treatment is dipped in glue solution of antifouling additive to obtain a wet nonwoven fabric with waterproof and antifouling properties.

[0076] Step 11: Post-treatment: The wet nonwoven fabric is dried to obtain a dry nonwoven fabric for filtration, wherein the drying method is a rotary mesh penetration drying at a drying temperature of 220°C.

[0077] Step 12: Cut and roll. The weight of the finished nonwoven fabric for filtration is 193g / m 2 , thickness is 1.25mm.

[0078] Furthermore, the performance of the nonwoven fabric for filtration of Example 2 was tested, and the specific test results are shown in Table 2.

[0079] Table 2

[0080]

[0081] Comparative Example 1

[0082] Comparative Example 1 uses the same method as in Example 1 to prepare a nonwoven fabric for filtration, except that: Comparative Example 1 does not use a shaped glass fiber mesh cloth. In other words, the nonwoven fabric of Comparative Example 1 only has a PET flat mesh fiber layer and a PTT first oblique mesh fiber layer.

[0083] Furthermore, the performance of the nonwoven fabric for filtration of Comparative Example 1 was tested, and the specific test results are shown in Table 3.

[0084] Table 3

[0085]

[0086] Comparative Example 2

[0087] Comparative Example 2 uses the same method as in Example 1 to prepare a nonwoven fabric for filtration, except that a woven glass fiber mesh cloth is used. In other words, the nonwoven fabric in Comparative Example 2 includes a PET flat mesh fiber layer, a glass fiber mesh cloth, and a PTT first oblique mesh fiber layer.

[0088] Furthermore, the performance of the nonwoven fabric for filtration of Comparative Example 2 was tested, and the specific test results are shown in Table 4.

[0089] Table 4

[0090]

[0091] Comparative Example 3

[0092] Comparative Example 3 uses the same method as in Example 1 to prepare a nonwoven fabric for filtration, except that a PTT oblique mesh fiber layer is used, and the oblique mesh fiber layer is double-layered. In other words, the nonwoven fabric in Comparative Example 3 includes a PTT first oblique mesh fiber layer and a PTT second oblique mesh fiber layer.

[0093] Furthermore, the performance of the nonwoven fabric for filtration of Comparative Example 3 was tested, and the specific test results are shown in Table 5.

[0094] Table 5

[0095]

[0096] It can be seen from the above embodiments and comparative examples that the nonwoven fabric of the present invention has excellent mechanical properties and impact resistance, and has high stability.

[0097] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A nonwoven fabric for filtering, comprising: A flat mesh fiber layer, a first oblique mesh fiber layer, and a shaped glass fiber mesh cloth located between the flat mesh fiber layer and the first oblique mesh fiber layer; The materials of the flat mesh fiber layer and the first oblique mesh fiber layer are independently selected from polyethylene terephthalate or polytrimethylene terephthalate; the shaped glass fiber mesh cloth is obtained by shaping and fixing the glass fiber mesh cloth with a shaping agent.

2. The nonwoven fabric for filtration according to claim 1, further comprising: a second oblique mesh fiber layer, wherein the material of the second oblique mesh fiber layer is the same as that of the first oblique mesh fiber layer; Wherein, the second oblique mesh fiber layer is arranged on a side of the first oblique mesh fiber layer close to the shaped glass fiber mesh cloth.

3. The nonwoven fabric for filtration according to claim 2, wherein: The fibers in the flat mesh fiber layer, the first oblique mesh fiber layer, and the second oblique mesh fiber layer are filaments.

4. The nonwoven fabric for filtration according to any one of claims 2 to 3, wherein The glass fiber mesh cloth is formed by cross-weaving transverse glass fibers and longitudinal glass fibers; The flat mesh fiber layer is formed by laying a single layer of fibers, and the first oblique mesh fiber layer and the second oblique mesh fiber layer are formed by cross-laying two layers of fibers.

5. The nonwoven fabric for filtration according to claim 1 or 2, wherein: Calculated in terms of fiber layer mass percentage, the flat mesh fiber layer accounts for 20%-80%, the oblique mesh fiber layer accounts for 20%-80%, and the total accounts for 100%.

6. The nonwoven fabric for filtration according to claim 5, wherein: The thickness of the flat mesh fiber layer is positively correlated with the mass percentage of the flat mesh fiber layer, and the thickness of the oblique mesh fiber layer is positively correlated with the mass percentage of the oblique mesh fiber layer; The setting agent comprises epoxy resin and amine curing agent.

7. The nonwoven fabric for filtration according to claim 2, further comprising: Antimicrobial substances and / or antifouling additives; The antibacterial substance and / or antifouling additive is located in at least one of the flat mesh fiber layer, the first oblique mesh fiber layer, and the second oblique mesh fiber layer.

8. A method for preparing a nonwoven fabric for filtration, comprising: The raw material of the flat mesh fiber layer and the raw material of the first oblique mesh fiber layer are respectively subjected to crystallization drying, metering spinning, cooling and drawing, and filament laying to obtain the flat mesh fiber layer and the first oblique mesh fiber layer; Adding a shaped glass fiber mesh cloth between the flat mesh fiber layer and the first oblique mesh fiber layer, fixing by needle punching and hot rolling to obtain a non-woven fabric for filtration; The raw material of the flat mesh fiber layer and the raw material of the first oblique mesh fiber layer are independently selected from polyethylene terephthalate or polytrimethylene terephthalate; the shaped glass fiber mesh cloth is obtained by shaping and fixing the glass fiber mesh cloth with a shaping agent.

9. The method according to claim 8, further comprising: The raw material of the second oblique web fiber layer is subjected to crystallization drying, metered spinning, cooling and drawing, and filament laying to obtain the second oblique web fiber layer; The second oblique mesh fiber layer is arranged on a side of the first oblique mesh fiber layer close to the shaped glass fiber mesh cloth, and is fixed by needle punching and hot rolling to obtain a non-woven fabric for filtration; The raw material of the second oblique mesh fiber layer is the same as the raw material of the first oblique mesh fiber layer.

10. The method according to claim 8 or 9, before the metered spinning, the method further comprises: Add antimicrobial substances; and / or After the hot rolling process, the method further comprises: The nonwoven fabric is immersed in a glue solution containing an antifouling additive and dried to obtain a nonwoven fabric for filtering.

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