Spunbond non-woven fabrics for liquid filter and method for preparing same

Abstract

The present invention relates to spunbond non-woven fabrics for a liquid filter and a method for preparing same. According to the present invention, provided are spunbond nonwoven fabrics for a liquid filter and a method for preparing same, wherein the spunbond nonwoven fabrics exhibit excellent filtration performance while having a high water pass-through rate.

Description

Spunbond nonwoven fabric for liquid filter and method for manufacturing the same

[0001] The present invention relates to a spunbond nonwoven fabric for a liquid filter and a method for manufacturing the same.

[0002]

[0003] A filter is a material or device that creates a pressure difference on both sides of a partition wall through which a gas or liquid containing another phase passes to separate the other phase from the gas or liquid.

[0004] Nonwoven fabrics are commonly used for filters. In particular, spunbond nonwoven fabrics are used in various industrial fields, including filters, due to their high productivity and excellent mechanical properties.

[0005] The performance of nonwoven fabrics for filters can vary depending on several factors that make up the nonwoven fabric. For example, the performance of nonwoven fabrics for filters can vary depending on factors such as the thickness, weight per unit area, and the fineness of the filaments that make up the nonwoven fabric.

[0006] Nonwoven fabrics for liquid filters typically require high water permeability and superior filtration efficiency. However, focusing on filtration efficiency in nonwoven fabrics for liquid filters tends to increase pressure loss, reducing water permeability and shortening their service life. Conversely, focusing on water permeability in nonwoven fabrics for liquid filters tends to extend their service life but decrease filtration efficiency.

[0007] Accordingly, there is a need for the development of a nonwoven fabric for liquid filters that has a high water permeability and excellent filtration performance, thus exhibiting a long service life.

[0008]

[0009] The present invention provides a spunbond nonwoven fabric for a liquid filter that has a high water permeability and exhibits excellent filtration performance.

[0010] And, the present invention provides a method for manufacturing the spunbond nonwoven fabric for the liquid filter.

[0011]

[0012] According to one embodiment of the invention,

[0013] A fiber web comprising a first polyester filament having a melting point of 250°C or higher and a second polyester filament having a melting point of 150°C to 220°C,

[0014] The above first polyester filament comprises a hollow cross-section filament and a heteromorphic cross-section filament having a fineness of 1 to 10 denier,

[0015] The hollow cross-section filament and the irregular cross-section filament have a fineness difference of 2 denier or more.

[0016] A spunbond nonwoven fabric for liquid filters is provided.

[0017]

[0018] According to another embodiment of the invention,

[0019] A step of forming a first polyester filament by melt spinning a first polyester having a melting point of 250°C or higher;

[0020] A step of forming a second polyester filament by melt spinning a second polyester having a melting point of 150°C to 220°C;

[0021] A step of forming a fiber web in which the first filament and the second filament are mixed; and

[0022] A step of heat treating the above fiber web under pressure to form a spunbond nonwoven fabric,

[0023] The above first polyester filament comprises a hollow cross-section filament and a heteromorphic cross-section filament having a fineness of 1 to 10 denier,

[0024] The hollow cross-section filament and the irregular cross-section filament have a fineness difference of 2 denier or more.

[0025] A method for manufacturing the spunbond nonwoven fabric for the above liquid filter is provided.

[0026]

[0027] Hereinafter, a spunbond nonwoven fabric for a liquid filter and a method for manufacturing the same according to embodiments of the present invention will be described in more detail.

[0028]

[0029] Unless explicitly stated otherwise in this specification, terminology is used only to describe specific embodiments and is not intended to limit the invention.

[0030] As used herein, the singular forms also include the plural forms unless the context clearly dictates otherwise.

[0031] As used herein, the term "including" means specifying a particular characteristic, region, integer, step, operation, element and / or component, but does not exclude the presence or addition of other particular characteristics, regions, integers, steps, operations, elements, components and / or groups.

[0032] In this specification, terms including ordinal numbers, such as "first" and "second," are used to distinguish one component from another and are not limited by the ordinal numbers. For example, within the scope of the present invention, the first component may also be referred to as the second component, and similarly, the second component may be referred to as the first component.

[0033] As used herein, "denier" is a unit of fineness based on the mass (grams) per 9000 meters of fiber length. For example, 1 denier can be expressed as 1 g / 9000 m, or 0.11 mg / m, or 0.11 tex.

[0034]

[0035] According to one embodiment of the invention,

[0036] A fiber web comprising a first polyester filament having a melting point of 250°C or higher and a second polyester filament having a melting point of 150°C to 220°C,

[0037] The above first polyester filament comprises a hollow cross-section filament and a heteromorphic cross-section filament having a fineness of 1 to 10 denier,

[0038] The hollow cross-section filament and the irregular cross-section filament have a fineness difference of 2 denier or more.

[0039] A spunbond nonwoven fabric for liquid filters is provided.

[0040]

[0041] As a result of the research of the present inventors, it was confirmed that a spunbond nonwoven fabric satisfying the configurations as in the above-mentioned implementation example can provide a long service life by exhibiting excellent filtration performance for liquids while having a high water permeability.

[0042] In particular, since the spunbond nonwoven fabric for the liquid filter includes filaments satisfying the above configurations, the amount of particles captured by the nonwoven fabric can be increased, while the pressure on the surface of the nonwoven fabric due to the particles and liquid flow rate can be reduced, thereby ensuring a long service life.

[0043] Accordingly, the above spunbond nonwoven fabric can be suitably used as a material for liquid filters such as swimming pool filters, water purifier filters, etc.

[0044]

[0045] According to one embodiment, the spunbond nonwoven fabric for the liquid filter comprises a fiber web in which first polyester filaments having a melting point of 250° C. or higher and second polyester filaments having a melting point of 150° C. to 220° C. are blended.

[0046]

[0047] The above first polyester filament has a melting point of 250°C or higher, or from 250°C to 265°C, or from 250°C to 260°C, or from 255°C to 260°C.

[0048] For example, the first polyester filament may include at least one first polyester selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polytetrafluoroethylene, and copolymers thereof that meet the melting point range.

[0049]

[0050] The second polyester filament has a melting point that is at least 30° C. lower than the first polyester filament. Preferably, the second polyester filament has a melting point of 150° C. to 220° C., or 160° C. to 220° C., or 160° C. to 210° C., or 170° C. to 210° C., or 180° C. to 210° C., or 190° C. to 210° C.

[0051] For example, the second polyester filament may include at least one second polyester selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polytetrafluoroethylene, and copolymers thereof that meet the melting point range.

[0052]

[0053] The fiber web comprises 70 to 95 wt% of the first polyester filament and 5 to 30 wt% of the second polyester filament. For example, the fiber web may comprise 75 to 95 wt% of the first polyester filament and 5 to 25 wt% of the second polyester filament. For another example, the fiber web may comprise 75 to 90 wt% of the first polyester filament and 10 to 25 wt% of the second polyester filament. For yet another example, the fiber web may comprise 75 to 85 wt% of the first polyester filament and 15 to 25 wt% of the second polyester filament.

[0054] In order to secure the bonding strength of the filaments in the above fiber web, it is preferable that the second polyester filaments are included in an amount of 5 wt% or more, or 10 wt% or more, or 15 wt% or more.

[0055] However, if the second polyester filament is excessively included in the fiber web, the mechanical properties of the fiber web may deteriorate due to a decrease in the content of the first polyester filament, and the workability of the spinning process and subsequent processes may deteriorate. Therefore, it is preferable that the second polyester filament is included in an amount of 30 wt% or less or 25 wt% or less.

[0056]

[0057] According to one embodiment, the first polyester filament comprises a hollow cross-section filament and a heterogeneous cross-section filament.

[0058]

[0059] The above hollow cross-section filament is a filament whose central cross-section is empty. The above hollow cross-section filament may have a hollow circular cross-section or a hollow irregular cross-section.

[0060] Preferably, the hollow cross-section filament may have a hollowness (a percentage of the inscribed circle area based on the circumscribed circle area of ​​the hollow cross-section) of 10% to 30%.

[0061] In order to maintain the hollow shape during the filament spinning process, it is preferable that the hollow cross-section filament has a hollowness ratio of 10% or more. However, if the hollowness ratio is excessive, the mechanical properties of the filament may deteriorate and it may be difficult to maintain the hollow shape. Therefore, it is preferable that the hollow cross-section filament has a hollowness ratio of 30% or less. Specifically, the hollowness of the hollow cross-section filament may be 10% to 30%, or 15% to 30%, or 15% to 25%.

[0062]

[0063] The above-described heteromorphic cross-section filament is a filament having a cross-section other than circular. For example, the above-described heteromorphic cross-section filament may have a Y-shaped, W-shaped, triangular, star-shaped, cross-shaped, flat, or multi-lobed cross-section.

[0064]

[0065] It is preferable that the hollow cross-section filament and the irregular cross-section filament included in the first polyester filament each have a fineness of 1 to 10 denier. In order to maintain the shape of the hollow cross-section and the irregular cross-section during the spinning process of the filament, it is preferable that the hollow cross-section filament and the irregular cross-section filament each have a fineness of 1 denier or more. However, in order to prevent deterioration of spinnability and operability, such as pack leakage, it is preferable that the hollow cross-section filament and the irregular cross-section filament each have a fineness of 10 denier or less.

[0066]

[0067] In particular, the hollow cross-section filament and the irregular cross-section filament have a fineness difference of 2 denier or more. Specifically, the fineness difference may be 2 denier or more, or 2 to 9 denier, or 2 to 8 denier, or 2 to 7 denier.

[0068] In order to realize excellent filtration performance and long service life of the spunbond nonwoven fabric for liquid filters, it is preferable that the hollow cross-section filament and the irregular cross-section filament have a fineness difference of 2 denier or more.

[0069] Under the above fineness conditions, the hollow cross-section filament may have a fineness greater or less than that of the heterogeneous cross-section filament.

[0070]

[0071] And, the first polyester filament may comprise 30 to 70 wt% of the hollow cross-section filament and 30 to 70 wt% of the irregular cross-section filament. For example, the first polyester filament may comprise 35 to 70 wt% of the hollow cross-section filament and 30 to 65 wt% of the irregular cross-section filament. In another example, the first polyester filament may comprise 35 to 65 wt% of the hollow cross-section filament and 35 to 65 wt% of the irregular cross-section filament. In yet another example, the first polyester filament may comprise 40 to 65 wt% of the hollow cross-section filament and 35 to 60 wt% of the irregular cross-section filament.

[0072] In order to realize excellent liquid filtration performance and long service life of the spunbond nonwoven fabric, it is preferable that the first polyester filament includes the hollow cross-section filament and the irregular cross-section filament within the above-described range.

[0073]

[0074] In one embodiment, the second polyester filament may be a circular cross-section filament.

[0075] Preferably, the second polyester filament may be a circular cross-section filament having a fineness of 1 to 5 denier, or 1 to 4 denier, or 2 to 4 denier. In order to secure the bonding strength of the filaments in the fiber web, it is preferable that the second polyester filament have a fineness within the above-described range.

[0076]

[0077] The weight and thickness of the spunbond nonwoven fabric for the above liquid filter are not particularly limited and can be adjusted within an appropriate range depending on the field of application.

[0078] Preferably, the spunbond nonwoven fabric for the liquid filter has a density of 50 g / m 2 350 g / m 2 , or 100 g / m 2 350 g / m 2 , or 100 g / m 2 300 g / m 2 , or 100 g / m 2 250 g / m 2 , or 120 g / m 2 250 g / m 2 , or 120 g / m 2 200 g / m 2 It can have a weight per unit area of ​​.

[0079] And, the spunbond nonwoven fabric for the liquid filter may have a thickness of 0.1 mm to 1.0 mm, or 0.2 mm to 1.0 mm, or 0.2 mm to 0.8 mm, or 0.3 mm to 0.8 mm, or 0.3 mm to 0.6 mm, or 0.4 mm to 0.6 mm, or 0.45 mm to 0.6 mm, or 0.45 mm to 0.55 mm.

[0080]

[0081] According to another embodiment of the invention,

[0082] A step of forming a first polyester filament by melt spinning a first polyester having a melting point of 250°C or higher;

[0083] A step of forming a second polyester filament by melt spinning a second polyester having a melting point of 150°C to 220°C;

[0084] A step of forming a fiber web in which the first filament and the second filament are mixed; and

[0085] A step of heat treating the above fiber web under pressure to form a spunbond nonwoven fabric,

[0086] The above first polyester filament comprises a hollow cross-section filament and a heteromorphic cross-section filament having a fineness of 1 to 10 denier,

[0087] The hollow cross-section filament and the irregular cross-section filament have a fineness difference of 2 denier or more.

[0088] A method for manufacturing the spunbond nonwoven fabric for the above liquid filter is provided.

[0089]

[0090] According to one embodiment, the spunbond nonwoven fabric for the liquid filter can be manufactured by a method of melt-spinning a first polyester and a second polyester to form a fiber web in which the first polyester filaments and the second polyester filaments are mixed, and heat-treating the web under pressure.

[0091]

[0092] In the above manufacturing method, the respective characteristics of the first polyester, the first polyester filament, the second polyester, and the second polyester filament are as described above.

[0093]

[0094] In one embodiment, the first polyester and the second polyester may be independently melted and spun through separate spun rods to form the first and second polyester filaments. Alternatively, the first polyester and the second polyester may be each melted and spun through a single spun rod for mixing, the number and shape of the spun rods of the different resins being adjustable, to form the first and second polyester filaments.

[0095] In particular, in the step of forming the first polyester filament, the hollow cross-section filament and the irregular cross-section filament can be obtained by spinning the molten first polyester through a nozzle capable of controlling the ratio of the hollow cross-section discharge holes and the irregular cross-section discharge holes.

[0096]

[0097] In the above melt spinning, the spinning speed and tension can be controlled taking into account the desired fineness of the first and second polyester filaments.

[0098] In addition, it is preferable that the steps of forming the first and second polyester filaments are each performed at a spinning speed of 4000 m / min to 6000 m / min, or 4500 m / min to 6000 m / min, or 4500 m / min to 5500 m / min. In order to form filaments having an appropriate degree of crystallinity, the spinning speed is preferably 4000 m / min or more, or 4500 m / min or more. However, if the spinning speed is excessive, filament entanglement may occur during the spinning process, which may lower the uniformity of the nonwoven fabric. Therefore, the spinning speed is preferably 6000 m / min or less, or 5500 m / min or less.

[0099]

[0100] The first and second polyester filaments are blended to form the fiber web. The blended first and second polyester filaments are laminated on a continuously moving net conveyor by a conventional opening method such as an electrostatic charging method, a collision plate method, and an air current diffusion method to form the fiber web. Here, the fiber web preferably contains 70 to 95 wt% of the first polyester filament and 5 to 30 wt% of the second polyester filament.

[0101]

[0102] Next, a step of heat treating the fiber web under pressure to form a spunbond nonwoven fabric is performed.

[0103] The above step is a step of obtaining a spunbond nonwoven fabric by thermally bonding the filaments included in the fiber web. For example, the fiber web is passed through a roller heated to approximately 200°C and dried with hot air, thereby obtaining a spunbond nonwoven fabric with appropriate smoothness and thickness. Conventional devices such as a calendar roller and a smooth roller can be used in the above step. The roller is heated to a temperature capable of melting the second polyester filaments to a bondable degree.

[0104]

[0105] According to the present invention, a spunbond nonwoven fabric for a liquid filter having a high water permeability and excellent filtration performance and a method for manufacturing the same are provided.

[0106]

[0107] Hereinafter, preferred embodiments are presented to aid understanding of the invention. However, the following examples are intended only to illustrate the invention and are not intended to limit the invention to these embodiments.

[0108]

[0109] Example 1

[0110] Polyethylene terephthalate (PET; first polyester) having a melting point of 255°C and co-polyester (Co-PET; second polyester) having a melting point of 210°C were each melted using a continuous extruder at 280°C.

[0111] The above first polyester melt was spun through a spinneret equipped with a spinneret having a hollow cross-section discharge hole and a deformed cross-section discharge hole to form hollow cross-section filaments (hollowness 10%) and deformed cross-section filaments (Y-shaped cross-section) having the finenesses described in Table 1 below. The continuous filaments spun through the spinneret were solidified with cooling air, and then stretched using a high-pressure air stretching device at a spinning speed of 5000 m / min to obtain a first polyester filament. At this time, the first polyester filament was prepared to include 50 wt% of the hollow cross-section filament and 50 wt% of the deformed cross-section filament.

[0112] The second polyester melt was spun through a nozzle having a circular cross-section discharge hole to form a second polyester filament having a fineness of 3 denier.

[0113] The first polyester filament and the second polyester filament were mixed in a weight ratio of 80:20 (weight %) and laminated on a continuously moving net conveyor to form a fiber web.

[0114] The above fiber web is passed through a smooth roller maintaining 200 ℃ and 35 N / mm and dried with hot air to produce a spunbond nonwoven fabric (weight per unit area 135 g / m 2 , thickness 0.51 mm) was manufactured.

[0115]

[0116] Examples 2 to 4 and Comparative Examples 1 to 4

[0117] A spunbond nonwoven fabric was manufactured in the same manner as in Example 1, except that the hollow cross-section filament and the irregular cross-section filament were manufactured to have the finenesses described in Table 1 below.

[0118] However, in Comparative Example 3, the production of nonwoven fabric was impossible due to leakage of the radiation pack during the radiation process.

[0119]

[0120] Filament Fineness (Denier)Spin Pack Pressure (Psi)Nonwoven Weight (g / m) 2 )Non-woven fabric thickness (mm) Hollow cross-section Deformed cross-section Example 16115631350.51 Example 26417511350.53 Example 39420541350.55 Example 42919351350.53 Comparative example 12211201350.43 Comparative example 29936901350.58 Comparative example 3133---Comparative example 45516231350.50

[0121]

[0122] Exam example

[0123] (1) Thickness of nonwoven fabric

[0124] The thickness of nonwoven fabric was measured according to KS K ISO 9073-2:2006 of the Korean Standards Association.

[0125] The distance between the reference plate on which the nonwoven fabric specimen was positioned and the pressurizer that was parallel to the reference plate and applied the specified pressure to the nonwoven fabric was measured. Ten nonwoven fabric specimens (20 cm x 20 cm) were prepared according to each of the examples and comparative examples, and the average value of their thickness is shown in Table 2 below. The ProGage Thickness Tester from Thwing-Albert Instrument was used to measure the thickness.

[0126]

[0127] (2) Filtration performance of nonwoven fabric

[0128] 2-1. Water flow

[0129] The liquid filtration performance of spunbond nonwoven fabrics was evaluated using a disk filter holder tester. Spunbond nonwoven fabric specimens (width x length = 0.525 cm x 0.225 cm) according to examples and comparative examples were prepared. Water containing dust particles was applied at a flow rate of 1.0 bar to the nonwoven fabric specimens, and the water passage (liter / min) was measured. The dust particles were 20 mg / m2 of A2 Fine TEST Dust of ISO-12103-1. 3 was applied at a concentration of .

[0130] 2-2. Filtration efficiency (%)

[0131] After the above water flow rate test, the filtration efficiency for particles with a diameter of 10 ㎛ or more among the dust particles was evaluated using a Liquid Particle Counter from PAMAS.

[0132]

[0133] (3) Radioactivity

[0134] When manufacturing nonwoven fabrics according to examples and comparative examples, the occurrence of filament detachment and breakage and the uniformity of the fiber web were evaluated based on the criteria below.

[0135] - ◎: ​​Filament detachment and breakage are very rare, and normal filaments are continuously laminated on the net to form a very uniform non-woven fabric.

[0136] - ○: Filament detachment and breakage are rare, and normal filaments are continuously laminated on the net to form a relatively uniform nonwoven fabric.

[0137] - △: Many filament breaks occur, and the filaments are not normal, but non-woven fabric can be formed.

[0138] - X: Filament breakage occurs frequently and the filaments are not normal, making it difficult to form non-woven fabric.

[0139]

[0140] Flow rate (liter / min) Filtration efficiency (%) Radioactivity Example 195.487.1○ Example 298.890.1◎ Example 3107.294.5○ Example 490.191.2○ Comparative Example 123.181.2△ Comparative Example 2130.143.9X Comparative Example 3---Comparative Example 480.161.4○

[0141]

[0142] Referring to Tables 1 and 2 above, the spunbond nonwoven fabrics of the examples are expected to have a long service life as a liquid filter, as they exhibit a filtration efficiency of 87.1% or more while having a water permeability of 90.1 liter / min or more.

[0143] The spunbond nonwoven fabrics of Comparative Examples 1 and 4 each exhibited inferior water permeability and filtration efficiency compared to the examples. The spunbond nonwoven fabric of Comparative Example 2 exhibited the highest water permeability but the lowest filtration efficiency, and thus is expected to have a short service life.

[0144]

[0145] Although the present invention has been described above through limited embodiments, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. A fiber web comprising a first polyester filament having a melting point of 250°C or higher and a second polyester filament having a melting point of 150°C to 220°C, The above first polyester filament comprises a hollow cross-section filament and a heteromorphic cross-section filament having a fineness of 1 to 10 denier, The above hollow cross-section filament and the above irregular cross-section filament have a fineness difference of 2 denier or more. Spunbond nonwoven fabric for liquid filters.

2. In paragraph 1, A spunbond nonwoven fabric for a liquid filter, wherein the fiber web comprises 70 to 95 wt% of the first polyester filaments and 5 to 30 wt% of the second polyester filaments.

3. In paragraph 1, A spunbond nonwoven fabric for a liquid filter, wherein the first polyester filament comprises 30 to 70 wt% of the hollow cross-section filament and 30 to 70 wt% of the irregular cross-section filament.

4. In paragraph 1, A spunbond nonwoven fabric for a liquid filter, wherein the hollow cross-section filaments and the irregular cross-section filaments have a fineness difference of 3 to 9 denier.

5. In paragraph 1, A spunbond nonwoven fabric for a liquid filter, wherein the hollow cross-section filaments have a hollowness (a percentage of the inscribed circle area based on the circumscribed circle area of ​​the hollow cross-section) of 10% to 30%.

6. In paragraph 1, The above-mentioned heterogeneous cross-section filaments are spunbond nonwoven fabrics for liquid filters having a Y-shaped, W-shaped, triangular, star-shaped, cross-shaped, flat, or multi-lobed cross-section.

7. In paragraph 1, A spunbond nonwoven fabric for a liquid filter, wherein the second polyester filament is a circular cross-section filament having a fineness of 1 to 5 denier.

8. In paragraph 1, 50 g / m 2 350 g / m 2 A spunbond nonwoven fabric for liquid filters, having a weight per unit area of:

9. In paragraph 1, A spunbond nonwoven fabric for liquid filters having a thickness of 0.1 mm to 1.0 mm.

10. A step of forming a first polyester filament by melt spinning a first polyester having a melting point of 250°C or higher; A step of forming a second polyester filament by melt spinning a second polyester having a melting point of 150°C to 220°C; A step of forming a fiber web in which the first filament and the second filament are mixed; and Comprising a step of heat treating the above fiber web under pressure to form a spunbond nonwoven fabric, The above first polyester filament comprises a hollow cross-section filament and a heteromorphic cross-section filament having a fineness of 1 to 10 denier, The above hollow cross-section filament and the above irregular cross-section filament have a fineness difference of 2 denier or more. A method for manufacturing a spunbond nonwoven fabric for a liquid filter according to claim 1.

11. In Article 10, A method for manufacturing a spunbond nonwoven fabric for a liquid filter, wherein the steps of forming the first polyester filament and the second polyester filament are each performed at a spinning speed of 4000 m / min to 6000 m / min.