KR100490515B1 - High-tenacity high-modulus drainage filter and preparation thereof - Google Patents

Abstract

The present invention is a high-strength, high-stiffness drainage filter material and a method of manufacturing the same, and a non-woven fabric made of long fiber having mechanical properties and chemical resistance, such as excellent tensile strength, tear strength, and bursting strength, compared to a conventional non-woven fabric made of short fibers. High-strength, high-stiffness drainage filter material formed of short fibers that have excellent process efficiency and low manufacturing cost as well as excellent sewing efficiency due to no entanglement that occurs during carding of long fibers while showing the same physical properties. And to a method for producing the same.

Description

High strength high rigidity drainage filter material and its manufacturing method {High-tenacity high-modulus drainage filter and preparation

The present invention relates to a drain filter material used in the soft ground and a manufacturing method thereof, and to a high strength high rigid drain filter material formed of short fibers.

The soft ground drainage filter material is composed of a two-layer structure that wraps the corrugated plastic core with the filter material. When it is installed vertically in the soft ground, the excess pore water in the ground passes through the filter material due to the osmotic pressure and the internal plastic core It is discharged upward through the drain. The filter material must maintain its original strength and rigidity in the wet state so as not to enter between the synthetic resin plates during the consolidation process of the soft ground, and sufficient water permeability without clogging caused by soil particles.

Conventionally, a heat-sealed nonwoven fabric made of short fibers or a nonwoven fabric containing a binder resin has been used, but such a short fiber nonwoven fabric has a mechanical property including strength and rigidity, clogging of soil particles due to excessive pore size, and poor water permeability. Therefore, it is not suitable as a filter material and is not currently used. Therefore, 100% polypropylene long fiber spunbond nonwoven fabric is now widely used as a filter material.

In the manufacturing method of the long fiber filter material, the spun polypropylene filament is stretched by a heating roller, the filament is forcibly charged by a corona discharge device, and a web is formed, and then in a steam chamber equipped with a calender roller. There is a method of manufacturing a spunbond nonwoven fabric by fusion bonding. The 100% polypropylene long fiber spunbond nonwoven fabric has excellent mechanical and chemical properties including tensile strength, tear strength, and tear strength, and excellent resistance to bacteria and microorganisms. Do. In addition, there is little creep even for a large compressive force and the pore size can be properly adjusted. However, since the non-woven fabric uses long fibers, when the general card machine is used instead of the corona discharge device, the web is not entangled with fibers in the card cloth, and the end product is expensive.

Therefore, the present invention is to provide a high-strength, high rigidity drain filter material formed of short fibers that can solve all the problems of the prior art as described above.

In order to solve the above problems, the inventors of the present invention use a synthetic fiber having a short fiber length without using the existing long fiber, thereby increasing the selection of raw materials and efficiently providing a web even in a general carding machine. It is possible to obtain a great effect on cost reduction, and by controlling the length of fiber used, the number of crimps, the punching density of the needle punching and the heat fusion temperature, it overcomes the shortcomings of short fiber nonwovens and is higher than the physical properties of long fiber nonwovens. The present invention has been completed by knowing that it is possible to manufacture a drainage filter material having excellent physical properties in the form of a plate.

Therefore, according to the present invention, in the method for producing a drainage filter material, the laminated fiber layer is formed after carding and laminating synthetic fibers having a fiber length of 40 to 65 mm, a crimp number of 5 to 7 pieces / cm, and a fineness of 4 to 8 deniers. There is provided a method for producing a high strength, high rigidity drainage filter material comprising needle punching at a punching density of 200 to 500 PPSC and thermally fusion at a heat fusion temperature of 100 to 130 ° C.

In addition, according to the manufacturing method is provided a high-strength, high rigidity drain filter material characterized in that the sheet formed by laminating and bonding the synthetic fibers of the short fibers comprises the following characteristics.

(a) tensile strength in the longitudinal direction of 950 to 1100, in the width direction of 930 to 1100 kgf / m,

(b) Initial stiffness is 4500 to 7000 in the longitudinal direction, 4000 to 6000 kgf / cm 2 in the width direction,

(c) the density is 0.5 to 0.8 g / cm 3,

(d) Permeability coefficient is 1 × 10 ⁻³ to 9 × 10 ⁻³ cm / sec and

(e) Effective hole size (AOS) is 70-110 micrometers.

Hereinafter, the present invention will be described in more detail.

The high strength high rigidity drain filter material of the present invention is manufactured by laminating and bonding using short synthetic fibers.

The raw material fibers are classified into matrix fibers and binder fibers, and the matrix fibers are preferably fibers which have high initial stiffness and can be used universally, such as polypropylene or polyester fibers. For the binder fiber, in order to pursue high strength and high rigidity and thereby form stability, it is preferable to select a composite type of heat-sealed fiber rather than a single type of heat-sealed fiber.

In order to satisfy the permeability coefficient and effective hole size (AOS) required as the drain filter material, the matrix fiber used in the present invention should carefully select the crimp number and the fiber length of the short fiber. The crimp number of short fibers is preferably 5-7 pieces / cm. If the number of crimps is too small, the carding process is unstable. If the number of crimps is too large, the web obtained is bulky, the coefficient of permeability and the effective hole size are small, and the shape stability Not good. In addition, the fiber length is most preferably about 40 to 65 mm. Fibers having a fiber length of less than 40 mm behave as floating fibers in the carding machine, resulting in high unevenness and loss rate of the web. The carding process becomes unstable due to entanglement or cutting between the needles, and the effective hole size becomes too large, so that the permeation effect is high, but soil or floating matter penetrates into the hole and eventually cannot drain. The short fiber diameter used as the drain filter material of the present invention is preferably in the range of 4 to 6 denier, but larger fineness, for example, 10 denier, has a disadvantage in that the uniformity of the fiber web is reduced and the surface of the fiber web is rough. The smaller fine fiber web has a disadvantage of insufficient strength.

In the present invention, the prepared fibers are arranged to form a web. As a method, a fiber web may be formed using a general carding machine as well as an aerodynamic method.

The molded fibrous web is primarily improved in strength through a needle punching process, which is a composite web bonding process. The stroke per minute of the needle punching machine is selected in consideration of the fiber web weight and manufacturing speed. The punching density is often applied to the PPSC (punching per square centimeter) unit in the present invention is preferably about 200 to 500 PPSC when the fiber web weight is 150 to 300g / ㎡. When the weight of the fiber web is small, it is preferable to reduce the punching density in order to prevent cutting of the fiber web constituent fibers. Most importantly, it is important to select the punching density so that the fibrous web can improve the tensile strength as much as possible through the punching process, especially 400 PPSC at 200g / m2. Such needle punching may be used in any case, such as a down stroke, an up stroke, and a double stroke. The up and down movement distance of the needle board should be set to 35 to 40mm because it prevents the short fibers from being scattered slightly. In addition, preliminary punching is also a good method, which is necessary to maintain uniform tensile strength.

After the needle punching is finished, the fiber web is fused by the binder fiber and the matrix fiber through a hot air process or a hot calendar process, thereby reinforcing the strength and rigidity secondarily. Low melting point polyethylene terephthalate (LMPET) / polyethylene terephthalate (PET), polyethylene (PE) / polyethylene terephthalate (PET) and polyethylene (PE) / polypropylene (PP), etc. currently used in general It is preferable to select the processing temperature of a calendering process in 100-130 degreeC. In the hot air process, heat is not directly applied to the fiber, and therefore, it is preferable to treat the fiber at a temperature higher than 10 ° C. above the heat calendar process. When polypropylene (PP) fiber is used as matrix fiber, when the treatment temperature is over 130 ℃, thermal shrinkage of matrix fiber is greatly occurred and yellowing phenomenon is severe, so the appearance of filter material is not good. There is a disadvantage in that the lack of required tensile strength.

Since the drain filter material should be thin like paper, the nip point spacing between the upper and lower rollers in the thermal calendar of the present invention is preferably 0.1 to 0.3 mm. The nip point spacing is equally applied to the nip point spacing for a general roller during hot air treatment.

In the present invention, it is possible to obtain the following waste filter material by the manufacturing method as described above. A drain filter material comprising: a high strength, high stiffness drain filter material comprising: a sheet formed by stacking and bonding synthetic fibers of short fibers;

(a) tensile strength in the longitudinal direction of 950 to 1100, in the width direction of 930 to 1100 kgf / m,

(b) Initial stiffness is 4500 to 7000 in the longitudinal direction, 4000 to 6000 kgf / cm 2 in the width direction,

(c) the density is 0.5 to 0.8 g / cm 3,

(d) Permeability coefficient is 1 × 10 ^-3 to 9 × 10 ^-3 cm / sec and

(e) Effective hole size (AOS) is 70-110 micrometers.

Drainage filter material used in soft ground should be thin and in case of soft ground type, it needs tensile strength to withstand it, and its original strength is tight even when wet so that no soil or floating material enters between synthetic resin plates during the consolidation process of soft ground. And rigidity must be maintained. In particular, the initial stiffness is large enough to maintain this state and the water permeability is good, so this initial stiffness is an important factor for the drain filter material. When the density of the drain filter material is less than 0.5 g / cm 3, the drain material is broken by the pressure, and thus it is impossible to serve as a sufficient drain filter. In addition, when the effective hole size (AOS) exceeds 110㎛, it is preferable to minimize the dust particles as they pass through the drain filter material, so that the smallest possible size is required. AOS) has a disadvantage in that the permeability is significantly lower. Therefore, the drainage filter material must have a permeability coefficient and at least 800kgf / m tensile strength and at least 3,500kgf / cm 2 initial stiffness, and there should be no clogging of the filter material.

The following examples are given as non-limiting examples of producing the high strength, high rigidity drain filter material of the present invention.

Example 1

As binder fibers, low melting polyethylene terephthalate (LMPET) / polyethylene terephthalate (PET) composite fibers were used, and matrix fibers were mixed using polypropylene (PP) fibers. Fineness and fiber length of binder fiber and matrix fiber are 6 denier and 64mm. The web forming process produced a random web by the aerodynamic method and the composition ratio of the raw fiber (matrix fiber / binder fiber) was 15/85. The web bonding process used a combination of a needle punching process and a thermal fusion process. The web weight was 190g / ㎡. The punching density was about 400 PPSC, and the heat filter temperature and winding speed were 110 ° C. and 1.5 m / min, respectively, in the heat fusion process to prepare drainage filter material.

Example 2

A drain filter material was manufactured in the same manner as in Example 1 except for changing the composition ratio, web weight, and heat fusion process of the raw material fibers (matrix fiber / binder fiber) as shown in Table 1.

Matrix / Binder Fiber Ratio Weight (g / ㎡) Heat Fusion Method Example 2 25/75 190 Thermal calendar method Example 3 35/65 190 Thermal calendar method Example 4 15/85 210 Hot air treatment Example 5 25/75 210 Hot air treatment Example 6 35/65 210 Hot air treatment

[Comparative Example]

The spunbonded sheet is formed by stretching the melt-spun polypropylene filament filament with a heating roller and forcibly charging the filament by a corona discharge device to form a web, and then fusion in a steam chamber equipped with a calender roller. Was prepared.

The mechanical properties of the drain filter material obtained by the above Examples and Comparative Examples were measured and shown in Table 2.

Tensile strength (kgf / m) Initial Stiffness (kgf / m) Tear strength (kgf) Density (g / cm 3) Permeability coefficient (× 10 ^-3 cm / s) Effective hole size (㎛) Longitudinal direction Width direction Longitudinal direction Width direction Example 1 1015 1006 6898 5863 7.6 0.63 1.5 108 Example 2 984 958 5717 4810 7.9 0.58 2.4 97 Example 3 954 931 5241 4629 9.1 0.53 5.8 92 Example 4 1085 1047 6275 5476 9.6 0.73 2.3 103 Example 5 1057 1043 5214 4819 9.6 0.64 3.8 91 Example 6 1051 1021 4897 4359 9.5 0.62 6.4 78 Comparative example 1034 1079 4424 4132 10.5 0.52 3.2 98

As described above, the drainage material according to the present invention is a high-strength, high-strength, thin and hard paper-like sheet, and has a new characteristic different from the conventional single fiber nonwoven filter material bonded by a simple heat welding process or a binder resin. It can maintain its original strength and stiffness even when wet, so that soil or suspended matter does not enter between synthetic resin boards while providing a permeability effect during the soft ground consolidation process. There is an advantage.

Claims (5)

In the method for producing a drainage filter material, after carding and laminating synthetic fibers having a fiber length of 40 to 65 mm, a crimp number of 5 to 7 pieces / cm, and a fineness of 4 to 8 deniers, the laminated fiber layer is punched at a density of 200 to 500. A method for producing a high strength, high strength drainage filter material comprising needle punching with PPSC and thermally fusion at a thermal fusion temperature of 100 to 130 ° C. delete The method of manufacturing a high strength high rigidity drain filter material according to claim 1, wherein the heat fusion method is a hot air or a hot calendar process. The method of manufacturing a high strength, high rigidity drain filter material according to claim 3, wherein the nip point spacing between the upper and lower rollers is 0.1 to 0.3 mm when thermally fused by the thermal calendar process. In the drain filter material, A high strength, high stiffness drainage filter material comprising: a sheet formed by laminating and bonding short fibers of synthetic fibers; (a) tensile strength in the longitudinal direction of 950 to 1100, in the width direction of 930 to 1100 kgf / m, (b) Initial stiffness is 4500 to 7000 in the longitudinal direction, 4000 to 6000 kgf / cm 2 in the width direction, (c) the density is 0.5 to 0.8 g / cm 3, (d) Permeability coefficient is 1 × 10 ^-3 to 9 × 10 ^-3 cm / sec and (e) Effective hole size (AOS) is 70-110 micrometers.