A polyester coated filter material for a folding filter cartridge and a method of making the same

Abstract

The present application relates to filter material technical field, specifically to a kind of polyester film-coated filter material for folding filter cartridge and its preparation method, comprising the following steps: (1) two-component low-melting point polyester staple fiber and ordinary polyester staple fiber are mixed to make polyester fiber web one and polyester fiber web two, and the content of two-component low-melting point polyester staple fiber in polyester fiber web one is higher than that in polyester fiber web two;(2) according to the stacking order of polyester fiber web one, polyester filament base cloth and polyester fiber web two, composite needling is carried out to make polyester needle felt;(3) high temperature hot pressing finishing is carried out on polyester needle felt to make stiff polyester needle felt;(4) the surface of one side of stiff polyester needle felt is covered with PTFE microporous membrane.This application uses two-component low-melting point polyester staple fiber and ordinary polyester staple fiber as one of raw materials, and uses high temperature hot pressing finishing to give stiffness to polyester needle felt, so that the filtration efficiency and service life of folding filter cartridge are greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of filter material, in particular to a polyester film-coated filter material for a folding filter cartridge and a preparation method thereof. BACKGROUND

[0002] The efficient operation of a dust collector cannot be achieved without the cooperation of filter elements. Filter elements can intercept dust particles in dust-containing gas, thereby purifying the air, protecting the environment and the health of workers. Common forms of filter elements include filter bags and folding filter cartridges. Filter bags are usually made of soft filter material and need to be fitted on a skeleton during use, which are suitable for handling fine dust particles. Folding filter cartridges are made of hard filter material folded inward into a cylindrical shape and do not require a skeleton for support. Compared with filter bags, folding filter cartridges have many advantages, including longer service life, better air permeability, larger filter area and higher dust removal efficiency.

[0003] In order to ensure the stability and filtering effect of the folding filter cartridge during use, the filter material of the folding filter cartridge also needs to meet certain requirements. The filter material commonly used in folding filter cartridges at present mainly includes polyester spunbond nonwoven folding filter material and polyester spunlace nonwoven folding filter material. The polyester spunbond nonwoven folding filter material is made of polymer chips through extrusion melting, spinning, webbing and hot rolling. The polyester spunlace nonwoven folding filter material is formed by water jet technology using polyester fibers. The disadvantages of these two types of filter materials are that the resistance to washing and service life are limited, and the filtering performance is heavily dependent on the PTFE film on the surface.

[0004] Therefore, it is necessary to develop a polyester film-coated filter material for a folding filter cartridge and a preparation method thereof. SUMMARY

[0005] In view of the problems of limited resistance to washing and service life of the polyester spunbond nonwoven folding filter material and the polyester spunlace nonwoven folding filter material, the present application provides a polyester film-coated filter material for a folding filter cartridge and a preparation method thereof.

[0006] In a first aspect, the present application provides a preparation method of a polyester film-coated filter material for a folding filter cartridge, comprising the following steps:

[0007] (1) mixing bicomponent low-melting-point polyester staple fibers and ordinary polyester staple fibers in different proportions, and then performing carding, cross-laying and needle punching to prepare a polyester fiber web 1 and a polyester fiber web 2, wherein the content of bicomponent low-melting-point polyester staple fibers in the polyester fiber web 1 is higher than that in the polyester fiber web 2;

[0008] (2) performing composite needle punching according to the stacking order of the polyester fiber web 1, a polyester filament base cloth and the polyester fiber web 2 to prepare a polyester needle-punched felt;

[0009] (3) performing high-temperature heat pressing on the polyester needle-punched felt to prepare a stiffened polyester needle-punched felt;

[0010] (4) covering the one side surface of the stiffened polyester needle felt with the polyester fiber web two with PTFE microporous film to obtain the polyester film-coated filter material for the folding filter cartridge.

[0011] Further, in the polyester fiber web one, the weight ratio of the bicomponent low-melting point polyester staple fiber and the ordinary polyester staple fiber is 30%:70%-50%:50%;

[0012] In the polyester fiber web two, the weight ratio of the bicomponent low-melting point polyester staple fiber and the ordinary polyester staple fiber is 10%:90%-50%:50%.

[0013] Further, the fineness of the bicomponent low-melting point polyester staple fiber and the ordinary polyester staple fiber is 2-5D, and the length of the bicomponent low-melting point polyester staple fiber and the ordinary polyester staple fiber is 38-64mm.

[0014] Further, the melting point of the bicomponent low-melting point polyester staple fiber is 110-180℃, and the melting point of the ordinary polyester staple fiber is 256℃.

[0015] Further, the density of the compound needling in step (2) is 60-200 needles / cm 2 , and the depth is 6-15mm.

[0016] Further, the grammage of the polyester filament base cloth is 30-100g / m 2 , and the grammage of the polyester needle felt is 150-500g / m 2 .

[0017] Further, the high-temperature hot pressing finishing is performed using a three-roller calender in step (3), the upper roller temperature is controlled to be 50-150℃, the middle roller temperature is controlled to be 110-220℃, the lower roller is not heated, and the hot pressing pressure is 0.5-5MPa.

[0018] Further, the porosity of the PTFE film is 50%-80%, the thickness is 2-15μm, and the air permeability is 5-20cm / s.

[0019] In a second aspect, the application provides a polyester film-coated filter material for a folding filter cartridge, which is prepared by the above preparation method.

[0020] The application has the following advantages:

[0021] The application uses bicomponent low-melting point polyester staple fiber and ordinary polyester staple fiber as one of the raw materials, uses needle punching process and high-temperature hot pressing finishing, the bicomponent low-melting point polyester staple fiber is partially melted and gives the stiffened polyester needle felt with stiffness through hot pressing, so that the filtration efficiency and service life of the folding filter cartridge are greatly improved, and the requirements for preparing the folding filter cartridge are met.

[0022] The application sets two-component low-melting-point polyester short fibers with different contents on both sides of the polyester filament base cloth, and obtains stiffened polyester needle felt through composite needling and hot pressing, and sets PTFE microporous film on the side with low content of two-component low-melting-point polyester short fibers, compared with the other side, the performance of the filter material is obviously improved, and unexpected technical effects are achieved.

[0023] The application uses needle punching method instead of the existing spunbond method and water jet method, and the filter material of the needle punching method has obvious dust washing resistance and more complex three-dimensional pore structure, so that the filtration efficiency and service life are improved. DETAILED DESCRIPTION

[0024] In order to enable the personnel in the technical field to better understand the technical solutions in the application, the technical solutions in the embodiments of the application will be clearly and completely described below, obviously, the described embodiments are only some of the embodiments of the application, not all. Based on the embodiments in the application, all other embodiments obtained by the personnel in the field without creative labor should belong to the protection scope of the application.

[0025] Embodiment 1

[0026] A polyester film-coated filter material for a folding filter cartridge is prepared by the following preparation method:

[0027] (1) mixing two-component low-melting-point polyester short fibers (2-2.5D, 38-64mm, melting point 110℃) and ordinary polyester short fibers (2-2.5D, 38-64mm, melting point 256℃) with a weight ratio of 30%:70%, and then preparing polyester web one through carding, cross-laying and needling;

[0028] mixing two-component low-melting-point polyester short fibers (2-2.5D, 38-64mm, melting point 110℃) and ordinary polyester short fibers (2-2.5D, 38-64mm, melting point 256℃) with a weight ratio of 10%:90%, and then preparing polyester web two through carding, cross-laying and needling;

[0029] (2) according to the stacking order of the polyester web one, 30g / m 2 The polyester filament base cloth and the polyester web two are composite needled, the needling density is 500 needles / cm 2 , the needling depth is 6-10mm, and the polyester needle felt with a weight of 200g / m 2 is prepared;

[0030] (3) using three-roller calender to polyester needle-punched felt high temperature hot pressing finishing, control the upper roller temperature is 50℃, the middle roller temperature is 190℃, the lower roller is not heated, hot pressing pressure is 5MPa, made of stiff polyester needle-punched felt;

[0031] (4) in the stiff polyester needle-punched felt set polyester fiber network two one side surface cover PTFE microporous film, PTFE film porosity is 50%, thickness is 2μm, air permeability is 5cm / s, made of polyester film filter material for folding filter cartridge.

[0032] Example 2

[0033] A kind of polyester film filter material for folding filter cartridge, is prepared by using the following preparation method:

[0034] (1) the weight ratio of 50%: 50% of two-component low-melting point polyester staple fiber (3-3.5D, 38-64mm, melting point 180℃) and ordinary polyester staple fiber (2-2.5D, 38-64mm, melting point 256℃) is mixed, through carding, cross-laid and needle-punched, made of polyester fiber network one;

[0035] The weight ratio of 30%: 70% of two-component low-melting point polyester staple fiber (3-3.5D, 38-64mm, melting point 180℃) and ordinary polyester staple fiber (2-2.5D, 38-64mm, melting point 256℃) is mixed, through carding, cross-laid and needle-punched, made of polyester fiber network two;

[0036] (2) according to polyester fiber network one, 100g / m 2 The stacking order of polyester filament base cloth and polyester fiber network two is compounded and needled, the needle density is 60 needles / cm 2 , the needle depth is 8-12mm, made of 300g / m 2 of polyester needle-punched felt;

[0037] (3) using three-roller calender to polyester needle-punched felt high temperature hot pressing finishing, control the upper roller temperature is 150℃, the middle roller temperature is 200℃, the lower roller is not heated, hot pressing pressure is 1MPa, made of stiff polyester needle-punched felt;

[0038] (4) in the stiff polyester needle-punched felt set polyester fiber network two one side surface cover PTFE microporous film, PTFE film porosity is 80%, thickness is 15μm, air permeability is 15cm / s, made of polyester film filter material for folding filter cartridge.

[0039] Example 3

[0040] A kind of polyester film filter material for folding filter cartridge, is prepared by using the following preparation method:

[0041] (1) The bicomponent low-melting point polyester staple fiber (4-4.5D, 38-64mm, melting point 150℃) and the ordinary polyester staple fiber (2-2.5D, 38-64mm, melting point 256℃) with a weight ratio of 40%:60% are mixed, carded, cross-laid and needled to prepare a polyester fiber web one;

[0042] The bicomponent low-melting point polyester staple fiber (4-4.5D, 38-64mm, melting point 150℃) and the ordinary polyester staple fiber (2-2.5D, 38-64mm, melting point 256℃) with a weight ratio of 25%:75% are mixed, carded, cross-laid and needled to prepare a polyester fiber web two;

[0043] (2) The polyester fiber web one, 50g / m 2 The polyester long filament base cloth and the polyester fiber web two are laminated and needled to prepare a 205g / m 2 polyester needle felt; 2

[0044] (3) The polyester needle felt is subjected to high-temperature heat pressing using a three-roller calender, the upper roller temperature is controlled at 100℃, the middle roller temperature is controlled at 150℃, the lower roller is not heated, and the heat pressing pressure is 2.5MPa to prepare a stiffened polyester needle felt;

[0045] (4) The stiffened polyester needle felt is covered with a PTFE microporous film on one side of the polyester fiber web two to prepare a polyester film-coated filter material for a folding filter cartridge.

[0046] Comparative Example 1

[0047] Comparative Example 1 is a polyester spunbond film-coated filter material, and the preparation process is as follows: the polyester resin raw material is melted, extruded into fine filaments by a spinning pump, then cooled and laid, and finally consolidated and formed by hot rolling or chemical bonding, and then covered with a PTFE film to prepare a film-coated filter material, with a grammage of 207g / m 2 .

[0048] Comparative Example 2

[0049] A polyester film-coated filter material for a folding filter cartridge is prepared by the following preparation method:

[0050] (1) The bicomponent low-melting point polyester staple fiber (4-4.5D, 38-64mm, melting point 150℃) and the ordinary polyester staple fiber (2-2.5D, 38-64mm, melting point 256℃) with a weight ratio of 40%:60% are mixed, carded, cross-laid and needled to prepare a polyester fiber web one;

[0051] ​The bicomponent low-melting point polyester staple fiber (4-4.5D, 38-64mm, melting point 150℃) and the common polyester staple fiber (2-2.5D, 38-64mm, melting point 256℃) with a weight ratio of 25%:75% are mixed, carded, cross-laid and needled to form a polyester web, and the polyester web is carded, cross-laid and needled to form a polyester web two;

[0052] (2) The polyester web one, 50g / m 2 The polyester filament base fabric and the polyester web two are laminated and needled, the needling density is 120 needles / cm 2 , the needling depth is 8-12mm, and a 205g / m 2 polyester needle felt is prepared;

[0053] (3) The polyester needle felt is subjected to high-temperature heat pressing using a three-roller calender, the upper roller temperature is controlled at 100℃, the middle roller temperature is controlled at 150℃, the lower roller is not heated, the heat pressing pressure is 2.5MPa, and a stiffened polyester needle felt is prepared;

[0054] (4) The stiffened polyester needle felt is covered with a PTFE microporous film on the side surface of the polyester web one, the porosity of the PTFE film is 80%, the thickness is 8μm, and the air permeability is 10cm / s, and a polyester film-coated filter material for a folding filter cartridge is prepared.

[0055] Test Example 1

[0056] The time for the film-coated filter materials of Examples 1-3 and Comparative Example 1 to be washed through by a high-pressure water gun with a pressure of 3.5MPa is determined, and the result is as follows:

[0057] The washing resistance time of the film-coated filter materials of Examples 1-3 is 4-4.5min, the washing resistance time of the film-coated filter material of Comparative Example 1 is 2.3min, and the washing resistance time of the film-coated filter material of Comparative Example 2 is 3.0min.

[0058] Test Example 2

[0059] The film-coated filter material prepared in Example 3 is taken as a representative, and the air permeability, stiffness and filtration efficiency of the film-coated filter material of the application and the film-coated filter material of Comparative Example 1 are compared. The test results are shown in Table 1.

[0060] Table 1 Test results of film-coated filter materials

[0061]

[0062] The test results of the comparative example and the comparative example 1 can show that, compared with the common spunbonded film filter material, the film filter material prepared by using the needle punching process and the high temperature heat pressing finishing with the bicomponent low melting point polyester staple fiber and the common polyester staple fiber as one of the raw materials has higher stiffness and higher resistance to flushing, and thus has longer service life. Meanwhile, the air permeability and the filtration efficiency of the film filter material of the present application are also better than those of the film filter material of the comparative example 1, because the three-dimensional interwoven filter material structure is formed by needle punching, and the point bonding and covering method can be used with the PTFE film, the original microporous structure of the PTFE film can be reserved, and the filtration efficiency can be improved.

[0063] The test results of the comparative example and the comparative example 2 can show that, the PTFE film is covered on the side with low content of the bicomponent low melting point polyester staple fiber on the surface of the stiff polyester needle felt, the stiffness, the air permeability, the filtration efficiency and the resistance to flushing of the film filter material are all higher, which shows that the service life of the film filter material is significantly improved, and the film filter material can better meet the use requirements of the foldable filter cartridge. When the content of the bicomponent low melting point polyester staple fiber on one side of the PTFE film is greater than that on the other side, the performances of the film filter material are all reduced.

[0064] Although the present application has been described in detail by means of the preferred embodiments, the present application is not limited to the embodiments. Various modifications and replacements can be made to the embodiments of the present application by those skilled in the art without departing from the spirit and scope of the present application, and these modifications and replacements shall be included in the scope of the present application. Any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, and these changes or replacements shall be included in the protection scope of the present application.

Claims

1. A method for preparing polyester membrane filter media for pleated filter cartridges, characterized in that, Includes the following steps: (1) Mix bicomponent low-melting-point polyester staple fiber and ordinary polyester staple fiber in different proportions, and then process them by carding, cross-laying and needle punching to make polyester fiber web one and polyester fiber web two. The content of bicomponent low-melting-point polyester staple fiber in polyester fiber web one is higher than that in polyester fiber web two. (2) Polyester fiber web one, polyester filament base fabric and polyester fiber web two are stacked in the order of composite needle punching to make polyester needle punch felt; (3) The polyester needle-punched felt is subjected to high-temperature hot pressing to produce stiff polyester needle-punched felt; (4) A PTFE microporous film is covered on one side of the stiff polyester needle-punched felt with polyester fiber web II to obtain polyester membrane filter material for folded filter cartridge.

2. The preparation method according to claim 1, characterized in that, In polyester fiber web type 1, the weight ratio of bicomponent low-melting-point polyester staple fiber to ordinary polyester staple fiber is 30%:70%-50%:50%; In polyester fiber web II, the weight ratio of bicomponent low-melting-point polyester staple fiber and ordinary polyester staple fiber is 10%:90%-50%:50%.

3. The preparation method according to claim 1, characterized in that, Both bicomponent low-melting-point polyester staple fiber and ordinary polyester staple fiber have a fineness of 2-5D and a length of 38-64mm.

4. The preparation method according to claim 1, characterized in that, The melting point of bicomponent low-melting-point polyester staple fiber is 110-180℃, while the melting point of ordinary polyester staple fiber is 256℃.

5. The preparation method according to claim 1, characterized in that, Step (2) The density of compound acupuncture is 60-200 needles / cm. 2 The depth is 6-15mm.

6. The preparation method according to claim 1, characterized in that, The basis weight of polyester filament base fabric is 30-100 g / m. 2 The basis weight of polyester needle-punched felt is 150-500 g / m². 2 .

7. The preparation method according to claim 1, characterized in that, Step (3) Use a three-roll calender for high-temperature hot pressing, control the temperature of the upper roll to be 50-150℃, the temperature of the middle roll to be 110-220℃, and the hot pressing pressure to be 0.5-5MPa.

8. The preparation method according to claim 1, characterized in that, PTFE films have a porosity of 50%-80%, a thickness of 2-15μm, and an air permeability of 5-20cm / s.

9. A polyester membrane filter media for folded filter cartridges prepared by the preparation method according to any one of claims 1-8.

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