A glass fiber filter paper, a preparation method and application thereof

Abstract

The present application relates to a kind of glass fiber filter paper and its preparation method and application.The glass fiber filter paper includes at least three layers of glass fiber layers, and the glass fiber layers between layer and layer are gradient arrangement;Three layers of the outer layer of the glass fiber layer is combined with non-woven fabric layer.The method includes: according to the proportion, at least three kinds of glass fiber, dispersing agent and water are uniformly mixed, and at least three kinds of glass fiber slurry are obtained;At least three kinds of glass fiber slurry are formed on the non-woven fabric laid on the paper forming net, and the glass fiber paper film is formed, is pressed and is initially dried, and at least three layers of dry paper film are obtained;At least three layers of paper film are released at the same speed, at the same time, the non-woven fabric on at least one middle layer paper film is removed, then at least three layers of paper film are glued and combined, and adhesive curing is carried out.The technical problem to be solved is how to make the thickness of glass fiber filter paper less than 0.5mm, the filter material quality less than 110g / m 2 , the breaking strength is higher than 210kPa, while the pollution capacity is higher than 160g / m 2 , and the filtering precision is better than β (10 μm) greater than 300.

Description

Technical Field

[0001] This invention relates to the field of glass fiber materials technology, and in particular to a glass fiber filter paper with high dirt holding capacity, high filtration ratio, and thinness, as well as its preparation method and application. Background Technology

[0002] Traditional plant fiber filter media cannot be used in high-temperature fuel, engine oil, and hydraulic oil systems due to their limited operating temperature. Metal fiber filter media meet the strength and temperature resistance requirements for oil filtration, but the high density of metal materials and the coarse diameter of metal fibers result in heavy filter media with lower filtration accuracy. Glass fiber filter media, with its low density, high temperature resistance, and filament diameter down to a few hundred nanometers, is the best alternative to traditional plant fiber and metal fiber filter media. However, current filter media are generally made of single-layer glass fiber composite nonwoven fabric to filter fuel, engine oil, etc. The dirt-holding capacity, filtration accuracy, and service life of this single-layer glass fiber paper are difficult to meet the high-precision requirements of rapidly developing technologies in the automotive, marine, heavy-duty vehicle, thermal power, nuclear power, and machining equipment industries.

[0003] The surface of glass fiber filter media lacks abundant functional groups, and its high stiffness makes it difficult to entangle and form a paper membrane. Furthermore, glass fiber-based filter media have low wet strength, making paper production challenging. The thickness of the glass fiber filter media significantly impacts filtration accuracy and dirt-holding capacity; therefore, current glass fiber-based filter media are generally thick and heavy, making it difficult to achieve lightweight design. Existing technology discloses a filter material with woven or non-woven fabric as the upper and lower layers and a filter layer in the middle, wherein the filter layer is composed of 96%–99% glass microfibers and 1%–4% synthetic fibers. Although this prior art mentions a three-layer filter paper, the upper and lower non-woven fabrics occupy two layers, leaving only one glass fiber filter layer in the middle. Therefore, filtration accuracy and dirt-holding capacity are not simultaneously improved. Summary of the Invention

[0004] In view of this, the main objective of this invention is to provide a glass fiber filter paper with high dirt holding capacity, high filtration ratio, and thinness, as well as its preparation method and application. The technical problem to be solved is how to make the thickness of the glass fiber filter paper less than 0.5 mm and the filter material mass less than 110 g / m³. 2 Its burst strength is higher than 210 kPa, and its dirt holding capacity is higher than 160 g / m³. 2 The filtration accuracy is better than β(10μm) greater than 300.

[0005] The objective of this invention and the technical problem it solves are achieved by the following technical solution. This invention proposes a glass fiber filter paper comprising at least three glass fiber layers arranged in a gradient between the layers; a non-woven fabric layer is laminated to the outer layer of the at least three glass fiber layers.

[0006] Preferably, in the aforementioned glass fiber filter paper, at least three of the glass fiber layers are composed of glass fibers of different diameters.

[0007] Preferably, in the aforementioned glass fiber filter paper, the diameter of the glass fiber is 0.1 μm-10 μm.

[0008] Preferably, in the aforementioned glass fiber filter paper, the nonwoven fabric layer is a nonwoven fabric of varying density with a basis weight of 10 g / m². 2 -40 g / m 2 .

[0009] Preferably, in the aforementioned glass fiber filter paper, the glass fiber diameter between at least three of the glass fiber layers exhibits a gradient change, and the pore size between the layers also exhibits a gradient change.

[0010] Preferably, in the aforementioned glass fiber filter paper, the thickness of the glass fiber filter paper is less than 0.5 mm and the basis weight is less than 110 g / m³. 2 Bursting strength higher than 210 kPa, dirt holding capacity higher than 160 g / m³ 2 The filtration ratio β (10μm) is greater than 300.

[0011] The objective of this invention and the technical problem it solves are achieved through the following technical solution. This invention proposes a method for preparing glass fiber filter paper, comprising the following steps:

[0012] At least three types of glass fibers, dispersant, and water are mixed evenly according to the formula to obtain at least three types of glass fiber slurries; the at least three types of glass fiber slurries are respectively used to form glass fiber paper films on non-woven fabric laid on a paper forming wire, and after pressing and initial drying, at least three dry paper films are obtained; the at least three paper films are released at the same speed, and at the same time, the non-woven fabric on at least one intermediate paper film is removed, and then the at least three paper films are sizing and laminating to obtain the glass fiber filter paper.

[0013] Preferably, in the aforementioned method for preparing glass fiber filter paper, the concentration of glass fiber is 0.0001 g / ml to 0.008 g / ml and the forming speed is 4 m / min to 40 m / min during the glass fiber paper membrane forming process.

[0014] Preferably, in the aforementioned method for preparing glass fiber filter paper, the pressing load is 5N-80N.

[0015] Preferably, in the aforementioned method for preparing glass fiber filter paper, the initial drying temperature is 80°C-150°C.

[0016] Preferably, in the aforementioned method for preparing glass fiber filter paper, the sizing ratio is 5wt%-10wt% based on the mass of at least three layers of paper film.

[0017] Preferably, in the aforementioned method for preparing glass fiber filter paper, the method includes the following steps:

[0018] S1. Mix the glass fiber A layer, dispersant and water evenly according to the formula to obtain the first glass fiber slurry;

[0019] S2. Lay the non-woven fabric on the paper forming mesh; then, form the first glass fiber slurry obtained in step S1 onto the non-woven fabric to obtain the first non-woven fabric paper film.

[0020] S3 involves pressing and initially drying the first nonwoven paper film obtained in step S2 to obtain a dried A-layer paper film.

[0021] S4 Mix the B-layer glass fiber, dispersant and water evenly according to the formula to obtain the second glass fiber slurry. Repeat steps S2-S3 to prepare the B-layer paper film.

[0022] S5 Mix the C-layer glass fiber, dispersant and water evenly according to the formula to obtain the third glass fiber slurry. Repeat steps S2-S3 to prepare the C-layer paper film.

[0023] S6 releases the A, B, and C layers of paper film at the same speed, while removing the non-woven fabric on the B layer of paper film. Then, the three layers of paper film are bonded together with adhesive and cured to obtain the glass fiber filter paper.

[0024] The objectives of this invention and the technical problems it solves can be further achieved by the following technical measures. This invention proposes a filter material comprising a filter layer, wherein the filter layer is made of the aforementioned glass fiber filter paper.

[0025] By employing the above technical solution, the glass fiber filter paper, its preparation method, and its application provided by the present invention have at least the following advantages:

[0026] The glass fiber filter paper provided by this invention adopts a multi-layer base paper composite, which has a significant gradient structure compared with traditional glass fiber filter paper. The pores inside the fiber paper show a gradual decrease in size from top to bottom. The small pores in the lower layer can effectively intercept small-sized pollutants, thereby improving the filtration ratio, while the large pores in the upper layer can accommodate more pollutants, effectively improving the dirt holding capacity. At the same time, this gradient structure reduces the resistance encountered by the fluid when passing through the glass fiber filter paper. Therefore, it overcomes the problem of simultaneously improving dirt holding capacity and filtration ratio, and realizes the preparation of high-performance adjustable glass fiber paper.

[0027] The glass fiber filter paper provided by this invention has excellent properties such as high dirt holding capacity, high filtration ratio, thinness, and high strength; its thickness is less than 0.5 mm and its basis weight is less than 110 g / m³. 2 Its burst strength is higher than 210 kPa, and its dirt holding capacity is higher than 160 g / m³. 2 The filtration accuracy is better than β(10μm) greater than 300.

[0028] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the glass fiber filter paper according to an embodiment of the present invention;

[0030] Figure 2 This is a SEM image of the glass fiber filter paper according to an embodiment of the present invention;

[0031] Wherein, 1-nonwoven fabric; 2-first glass fiber layer; 3-second glass fiber layer; 4-third glass fiber layer. Detailed Implementation

[0032] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following detailed description, in conjunction with preferred embodiments, provides a detailed explanation of the specific implementation methods, structures, features, and effects of a glass fiber filter paper and its preparation method according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0033] Unless otherwise specified, all materials or reagents mentioned below are commercially available, and the methods described are conventional methods.

[0034] Some embodiments of the present invention provide a glass fiber filter paper comprising at least three glass fiber layers, each layer composed of glass fibers with different diameter ratios, exhibiting a gradient change in glass fiber diameter and pore size between layers, effectively increasing dirt holding capacity and filtration ratio; the outer layer of the at least three composite glass fiber layers is composited with a non-woven fabric layer, which provides strength and protection for the glass fiber filter paper. This design overcomes the existing challenge of simultaneously increasing dirt holding capacity and filtration ratio while controlling the thickness of the glass fiber filter. Specifically, as... Figure 1As shown, the glass fiber filter paper comprises three glass fiber layers, namely, a first glass fiber layer 2, a second glass fiber layer 3, and a third glass fiber layer 4, with different layers composed of glass fibers of different diameters. The outer layer of the three composite glass fiber layers is composited with a non-woven fabric layer 1.

[0035] In the above technical solution, at least three glass fiber layers are composed of glass fibers of different diameters; the resulting pore size is distributed in an inverted trapezoidal shape, which can reduce energy loss during fluid flow, that is, reduce the pressure difference between the upper and lower surfaces of the filter paper, thereby increasing the dirt holding capacity.

[0036] In specific implementation, the diameter of the glass fiber can be 0.1μm-10μm (including glass fibers prepared by conventional drawing, spinning and other processes). If the diameter is greater than 10μm, the diameter of the glass fiber is too high, resulting in an excessively large pore size, which cannot effectively intercept pollutants. If the diameter is less than 0.1μm, the diameter is too low, resulting in a small pore size, which increases the pressure difference between the top and bottom of the filter paper, thus hindering the improvement of the dirt holding capacity.

[0037] Depending on the external forces acting on the filter material during use, the nonwoven fabric layer can be a nonwoven fabric of different densities, with a basis weight of 10 g / m². 2 -40 g / m 2 .

[0038] Furthermore, some embodiments of the present invention also provide a method for preparing glass fiber filter paper, comprising the following steps:

[0039] At least three types of glass fibers, dispersant, and water are mixed evenly according to the formula to obtain at least three types of glass fiber slurries; the at least three types of glass fiber slurries are respectively formed into glass fiber paper films on non-woven fabric laid on a paper forming wire, and after pressing and initial drying, at least three dry paper films are obtained; the at least three paper films are released at the same speed, while the non-woven fabric on at least one intermediate paper film is removed, and then the at least three paper films are glued and laminated, and the adhesive is cured to obtain the glass fiber filter paper.

[0040] Specifically, the preparation method may include the following steps:

[0041] 1) Weigh the A-layer glass fiber, sodium silicate dispersant, and water according to the mass ratio and put them into a mixing tank for stirring and mixing to obtain a first glass fiber slurry with a concentration of 0.0001 g / ml-0.008 g / ml. Specifically, the mass ratio of the A-layer glass fiber to the sodium silicate dispersant can be (100-2000):1. If the mass ratio is greater than 2000:1, the sodium silicate content is too low and the glass fiber cannot be well dispersed; if the mass ratio is less than 100:1, the sodium silicate dispersant is too high, resulting in a viscous liquid that is difficult to disperse and affects paper forming.

[0042] 2) Lay the nonwoven fabric on the paper forming wire of the papermaking equipment.

[0043] 3) The first glass fiber slurry in the mixing tank is drawn into the distributor. The concentration of the first glass fiber is adjusted within the range of 0.0001 g / ml to 0.008 g / ml, and the forming wire speed is adjusted within the range of 4 m / min to 40 m / min. If the concentration is less than 0.0001 g / ml, the glass fiber slurry concentration is too low; if the speed is greater than 40 m / min, the forming wire speed is too fast, and continuous paper cannot be formed. If the concentration is greater than 0.008 g / ml, the glass fiber slurry concentration is too high; if the speed is less than 4 m / min, the forming wire speed is too low, which will lead to glass fiber accumulation. Glass fiber paper film is formed on nonwoven fabric to obtain the first nonwoven paper film. The extraction can be carried out using any glass fiber slurry extraction method in the prior art, and this invention does not impose specific limitations.

[0044] 4) Press the first nonwoven paper film in step 3) with a load of 5N-80N. When the load is greater than 80N, the pressure is too high and the glass fiber is easily crushed; when the load is less than 5N, the pressure is too low and the excess water cannot be effectively squeezed out.

[0045] 5) The first nonwoven glass fiber paper film obtained in step 4) is initially dried at 80-150℃ to obtain the dried A layer paper film. If the temperature is below 80℃, it will be too low to dry; if the temperature is above 150℃, it will be too high and lead to wasted energy.

[0046] 6) Weigh out glass fibers and sodium silicate dispersant of different diameters required for the B layer paper membrane according to the different ratios between the three-layer or multi-layer paper, and repeat steps 1)-5) to prepare the B layer paper membrane. Weigh out glass fibers and sodium silicate dispersant of different diameters required for the C layer paper membrane according to the different ratios between the three-layer or multi-layer paper, and repeat steps 1)-5) to prepare the C layer paper membrane. The mass ratio of the A, B, and C layers of paper membrane is (1-5):(1-5):(1-5). Mismatched multilayer ratios will result in the inability to improve the dirt holding capacity and filtration ratio; for example, it can be 1:1:1, 2:2:1, or 3:3:2. In addition, if the A layer paper membrane uses 10μm glass fibers, then the diameter of the glass fibers used in the B and C layers of paper membrane gradually decreases.

[0047] 7) The A, B, and C layers of paper film are released at the same speed using a feeding roller, while the non-woven fabric on the B layer is removed. This allows the three layers to bond better, and the three layers are initially composited using a circular roller. The non-woven fabric in the B layer provides support for the B layer paper film, especially when this layer is thin. Adding non-woven fabric in the middle increases the overall weight and does not improve filtration performance. Therefore, removing the non-woven fabric is necessary for bonding with the upper and lower glass fiber filter paper layers. The same-speed release can be achieved using any existing method for releasing the original paper at the same speed; this invention does not impose specific limitations. The three layers of paper film are then bonded together using an adhesive applicator and subsequently placed in a drying oven or drying cylinder at 120℃-210℃ for adhesive curing. If the temperature is below 120℃, the adhesive will not cure properly, and the filter material strength will not improve. If the temperature is above 210℃, it will not only waste resources but also damage the adhesive. Based on the mass of the three-layer paper film, the adhesive application ratio is 5wt%-10wt%. If the ratio is less than 5wt%, the adhesive content is too low and will not stabilize the fibers of the fiberglass paper film. If the adhesive application is greater than 10wt%, the adhesive content is too high and will clog the pores. Considering the curing temperature of 120-210℃, the adhesive can be selected as a water-soluble resin adhesive.

[0048] The above technical solution involves mixing and combining glass fibers of different diameters, preparing and compounding them in layers, and then increasing their strength by impregnating them with a water-soluble adhesive for curing. During the preparation process, by controlling the glass fiber diameter and content ratio, a glass fiber filter paper with high dirt-holding capacity, high filtration ratio, thinness, and high strength is synthesized.

[0049] Some embodiments of the present invention also provide a filter material, including a filter layer, wherein the filter layer is made of the aforementioned glass fiber filter paper. The filter material includes oil filter elements used in the automotive, aerospace, and industrial fields.

[0050] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0051] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0052] The thickness and basis weight (i.e., the mass per unit area of ​​the filter material) are tested according to GB / T451; the burst strength is tested according to GB / T454.

[0053] Example 1

[0054] This embodiment provides a method for preparing glass fiber filter paper, including the following steps:

[0055] 1) Weigh 10kg of A-layer glass fiber (glass fiber cotton with a filament diameter of 7 micrometers) and 0.02kg of sodium silicate dispersant according to the formula and put them into a mixing tank to mix with water and stir to prepare the first glass fiber slurry with a concentration of 0.002g / ml.

[0056] 2) The weight is 15g / m 2 Non-woven fabric is laid on the paper forming wire of the papermaking equipment.

[0057] 3) The first glass fiber slurry in the mixing tank is extracted into the slurry distributor and formed into a glass fiber paper film on the nonwoven fabric at a speed of 10 m / min to obtain the first nonwoven paper film.

[0058] 4) The first nonwoven paper film obtained in step 3) is pressed under a load of 10N to obtain the first nonwoven glass fiber paper film.

[0059] 5) The first nonwoven glass fiber paper film obtained in step 4) is initially dried at 100°C for 2 minutes to obtain the dried A layer paper film.

[0060] 6) Weigh 10 kg of B-layer glass fiber (glass fiber cotton with a filament diameter of 4 micrometers) according to the formula, and add it to a mixing tank with water and stir to prepare a second glass fiber slurry with a concentration of 0.002 g / ml. Repeat steps 2)-5) to prepare the B-layer paper film. Weigh 10 kg of C-layer glass fiber (glass fiber cotton with a filament diameter of 2 micrometers) according to the formula, and add it to a mixing tank with water and stir to prepare a third glass fiber slurry with a concentration of 0.002 g / ml. Repeat steps 2)-5) to prepare the C-layer paper film.

[0061] 7) The dried A, B, and C layers of paper film are released at the same speed of 5 m / min by the feeding roller, while the non-woven fabric on the B layer of paper film is removed. The three layers of paper film are initially bonded by the circular roller. The paper film enters the sizing device, where 8 wt% (based on the mass of the three layers of paper film) of adhesive (specifically a water-soluble resin adhesive) is applied to the three layers of paper film for bonding. The paper film is then dried in a drying oven at 120°C for 20 minutes to cure the adhesive and obtain the glass fiber filter paper.

[0062] According to tests conducted by multi-pass testing equipment, the dirt-holding capacity of the three-layer glass fiber filter paper prepared in this embodiment is as high as 235 g / m³. 2 The filtration ratio β (10μm) is 697, the thickness is 0.46mm, and the basis weight is 98g / m³. 2Its bursting strength is 280 kPa.

[0063] Example 2

[0064] This embodiment provides a method for preparing glass fiber filter paper, including the following steps:

[0065] 1) Weigh 10kg of A-layer glass fiber (glass fiber cotton with a filament diameter of 6 micrometers) and 0.02kg of sodium silicate dispersant according to the formula, put them into a mixing tank and mix them with water to prepare the first glass fiber slurry with a concentration of 0.002g / ml.

[0066] 2) The weight is 15g / m 2 Non-woven fabric is laid on the paper forming wire of the papermaking equipment.

[0067] 3) The first glass fiber slurry in the mixing tank is extracted into the slurry distributor and formed into a glass fiber paper film on the nonwoven fabric at a speed of 10 m / min to obtain the first nonwoven paper film.

[0068] 4) The first nonwoven paper film obtained in step 3) is pressed under a load of 10N to obtain the first nonwoven glass fiber paper film.

[0069] 5) The first nonwoven glass fiber paper film obtained in step 4) is initially dried at 100°C for 3 minutes to obtain the dried A layer paper film.

[0070] 6) Weigh 10 kg of B-layer glass fiber (glass fiber cotton with a filament diameter of 4 micrometers) according to the formula, and add it to a mixing tank with 0.02 kg of sodium silicate dispersant. Mix and stir to prepare a second glass fiber slurry with a concentration of 0.002 g / ml. Repeat steps 2)-5) to prepare the B-layer paper film. Weigh 10 kg of C-layer glass fiber (glass fiber cotton with a filament diameter of 2 micrometers) according to the formula, and add it to a mixing tank with 0.02 kg of sodium silicate dispersant. Mix and stir to prepare a second glass fiber slurry with a concentration of 0.002 g / ml. Repeat steps 2)-5) to prepare the C-layer paper film.

[0071] 7) The dried A, B, and C layers of paper film are released at the same speed of 5 m / min by the feeding roller, while the non-woven fabric on the B layer of paper film is removed. The three layers of paper film are initially bonded by the circular roller. The paper film enters the sizing device, where 8 wt% (based on the mass of the three layers of paper film) of adhesive (specifically a water-soluble resin adhesive) is applied to the three layers of paper film for bonding. The paper film is then dried in a drying oven at 120°C for 20 minutes to cure the adhesive and obtain the glass fiber filter paper.

[0072] The glass fiber filter paper prepared in this embodiment was observed by scanning electron microscopy as follows: Figure 2 As shown. From Figure 2The cross-section of the fiberglass paper shows that the pore size of the fiberglass filter paper gradually decreases.

[0073] According to tests conducted by multi-pass testing equipment, the dirt-holding capacity of the three-layer glass fiber filter paper prepared in this embodiment is as high as 210 g / m³. 2 The filtration ratio β (10μm) is 1037, the thickness is 0.44mm, and the basis weight is 95g / m³. 2 Its burst strength is 295 kPa.

[0074] Example 3

[0075] This embodiment provides a method for preparing glass fiber filter paper, including the following steps:

[0076] 1) Weigh 5 kg of A-layer glass fiber (glass fiber cotton with a filament diameter of 10 micrometers) and 5 kg of A-layer glass fiber (glass fiber cotton with a filament diameter of 5 micrometers) according to the formula, and put them into a mixing tank with water in sequence with 0.02 kg of sodium silicate dispersant to prepare the first glass fiber slurry with a concentration of 0.002 g / ml.

[0077] 2) The weight is 15g / m 2 Non-woven fabric is laid on the paper forming wire of the papermaking equipment.

[0078] 3) The first glass fiber slurry in the mixing tank is extracted into the slurry distributor and formed into a glass fiber paper film on the nonwoven fabric at a speed of 10 m / min to obtain the first nonwoven paper film.

[0079] 4) The first nonwoven paper film obtained in step 3) is pressed under a load of 10N to obtain the first nonwoven glass fiber paper film.

[0080] 5) The first nonwoven glass fiber paper film obtained in step 4) is initially dried at 100°C for 3 minutes to obtain the dried A layer paper film.

[0081] 6) Weigh 10 kg of B-layer glass fiber (glass fiber cotton with a filament diameter of 4 micrometers) according to the formula, and add it to a mixing tank with water and stir to prepare a second glass fiber slurry with a concentration of 0.002 g / ml. Repeat steps 2)-5) to prepare the B-layer paper film. Weigh 10 kg of C-layer glass fiber (glass fiber cotton with a filament diameter of 1 micrometer) according to the formula, and add it to a mixing tank with water and stir to prepare a third glass fiber slurry with a concentration of 0.002 g / ml. Repeat steps 2)-5) to prepare the C-layer paper film.

[0082] 7) The dried A, B, and C layers of paper film are released at the same speed of 5 m / min by the feeding roller, while the non-woven fabric on the B layer of paper film is removed. The three layers of paper film are initially bonded by the circular roller. The paper film enters the sizing device, where 8 wt% (based on the mass of the three layers of paper film) of adhesive (specifically a water-soluble resin adhesive) is applied to the three layers of paper film for bonding. The paper film is then dried in a drying oven at 120°C for 20 minutes to cure the adhesive and obtain the glass fiber filter paper.

[0083] According to tests conducted by multi-pass testing equipment, the dirt-holding capacity of the three-layer glass fiber filter paper prepared in this embodiment is as high as 223 g / m³. 2 The filtration ratio β (10μm) is 1978, the thickness is 0.42mm, and the basis weight is 95g / m³. 2 Its bursting strength is 302 kPa.

[0084] Example 4

[0085] The difference between this embodiment and embodiment 1 is that the glass fiber layer in this embodiment is 4 layers, including a fourth glass fiber layer D. 5 kg of glass fiber (glass fiber with a diameter of 1 micrometer) of layer D is weighed according to the formula and put into a mixing tank with 0.02 kg of sodium silicate dispersant in sequence and mixed with water. The mixture is stirred to prepare a fourth glass fiber slurry with a concentration of 0.002 g / ml. Steps 2) to 5) are repeated to prepare the D layer paper film.

[0086] After testing with multiple testing devices, the dirt-holding capacity of the four-layer glass fiber filter paper prepared in this embodiment reached as high as 243 g / m³. 2 The filtration ratio β (10μm) is 5037, the thickness is 0.47mm, and the basis weight is 97g / m³. 2 Its bursting strength is 313 kPa.

[0087] Example 5

[0088] The difference between this embodiment and embodiment 1 is that in step 6) of this embodiment, 5 kg each of glass fiber B layer with a diameter of 7 micrometers and 4 micrometers are weighed according to the ratio and put into a mixing tank with 0.02 kg of sodium silicate dispersant and mixed with water to prepare a second glass fiber slurry with a concentration of 0.002 g / ml. Steps 2)-5) are repeated to prepare the B layer paper film.

[0089] After testing with multiple testing devices, the dirt-holding capacity of the three-layer glass fiber filter paper prepared in this embodiment reached as high as 249 g / m³. 2 The filtration ratio β (10μm) is 450, the thickness is 0.45mm, and the basis weight is 96g / m³. 2 Its bursting strength is 287 kPa.

[0090] Comparative Example 1

[0091] 1) Weigh 10kg of A-layer glass fiber (glass fiber cotton with a filament diameter of 6 micrometers) and 0.02kg of sodium silicate dispersant according to the formula, put them into a mixing tank and mix them with water to prepare the first glass fiber slurry with a concentration of 0.002g / ml.

[0092] 2) The weight is 15g / m 2 Non-woven fabric is laid on the paper forming wire of the papermaking equipment.

[0093] 3) The first glass fiber slurry in the mixing tank is drawn into the slurry distributor and formed into a glass fiber paper film on the nonwoven fabric at a speed of 6 m / min to obtain the first nonwoven paper film.

[0094] 4) The first nonwoven paper film obtained in step 3) is pressed under a load of 10N to obtain the first nonwoven glass fiber paper film.

[0095] 5) The first nonwoven glass fiber paper film obtained in step 4) is initially dried at 100°C for 3 minutes to obtain the dried A layer paper film.

[0096] 6) Weigh 10 kg of B-layer glass fiber (glass fiber cotton with a filament diameter of 2 micrometers) according to the formula, and put it into a mixing tank with 0.02 kg of sodium silicate dispersant in sequence. Mix and stir to prepare a second glass fiber slurry with a concentration of 0.002 g / ml. Repeat steps 2) to 5) to prepare the B-layer paper film.

[0097] 7) The dried A and B layers of paper film are released at the same speed of 5 m / min by the feeding roller, while the non-woven fabric on the B layer of paper film is removed. The two layers of paper film are initially bonded by the circular roller. The paper film enters the sizing device, where 8 wt% (based on the mass of the three layers of paper film) of adhesive (specifically a water-soluble resin adhesive) is applied to the three layers of paper film for bonding. The paper film is then dried in a drying oven at 120°C for 20 minutes to cure the adhesive and obtain the glass fiber filter paper.

[0098] According to tests conducted using multiple testing devices, the dirt-holding capacity of the two-layer glass fiber filter paper prepared in this comparative example is 96 g / m³. 2 The filtration ratio β (10μm) is 279, the thickness is 0.41mm, and the basis weight is 90g / m³. 2 Its bursting strength is 227 kPa.

[0099] Because this comparative example lacks the gradient transition of multiple intermediate glass fiber layers, the fluid experiences greater resistance when flowing through the filter paper where the pore size suddenly decreases from large to small. The pressure difference between the upper and lower surfaces is quickly reached, making it difficult to simultaneously increase the dirt holding capacity and filtration ratio.

[0100] Single-layer glass fiber filter paper prepared from a mixture of fibers of different coarseness and fineness is difficult to control simultaneously in terms of dirt holding capacity and filtration ratio. While double-layer glass fiber filter paper prepared from glass fibers can control both dirt holding capacity and filtration ratio, the adjustment range is limited. As can be seen from Examples 1-5, the glass fiber filter paper of this invention has a thickness of 0.42mm-0.47mm and a basis weight of 95g / m³. 2 -98 g / m 2 Its burst strength is 280kPa-313kPa, and its dirt holding capacity is 210g / m³. 2 -249 g / m 2 The filtration ratio β (10μm) is 450-5037. By reducing the thickness of each layer of glass fiber filter paper, three or more layers of glass fiber filter paper can be prepared, which can construct a gradient structure in which the internal pore size of the glass fiber filter paper gradually decreases, effectively reducing the resistance when the fluid flows through the pore size. Therefore, the three or more layers of gradient glass fiber filter paper proposed in this invention can achieve the requirements of ultra-large dirt holding capacity and high filtration ratio.

[0101] By adjusting the number of fiberglass paper layers and the combination of fiberglass diameters, the dirt holding capacity and filtration ratio can be effectively improved. Using larger diameter fiberglass helps increase dirt holding capacity, but reduces filtration efficiency. By constructing a multi-layer gradient structure, especially when the transition between the transition layer and the upper and lower fiber layers is relatively smooth, the dirt holding capacity and filtration ratio can be maximized.

[0102] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0103] The numerical range described in this invention includes all values ​​within this range, and also includes any range value composed of any two values ​​within this range. Different values ​​of the same indicator appearing in all embodiments of this invention can be arbitrarily combined to form a range value.

[0104] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A type of glass fiber filter paper, characterized in that, The glass fiber filter paper comprises at least three glass fiber layers, with the glass fiber layers arranged in a gradient. A non-woven fabric layer is laminated to the outer layer of each of the at least three glass fiber layers. Each of the at least three glass fiber layers is composed of glass fibers of different diameters. The glass fiber diameters and pore sizes of the at least three glass fiber layers exhibit a gradient variation. The glass fiber diameters used in the three glass fiber layers are 7μm, 4μm, and 2μm; or 6μm, 4μm, and 2μm; or a mass ratio of... The glass fiber filter paper is prepared in a 1:1 ratio with 10μm and 5μm filaments as the first layer, 4μm filaments as the second layer, and 1μm filaments as the third layer; or with 7μm filaments as the first layer, 7μm and 4μm filaments as the second layer, and 2μm filaments as the third layer; or with four layers of glass fiber using glass fiber filaments of 7μm, 4μm, 2μm, and 1μm diameter; the thickness of the glass fiber filter paper is less than 0.5mm, and the basis weight is less than 110g. Bursting strength higher than 210 kPa, dirt holding capacity higher than 160 kPa The filtration ratio β of 10μm is greater than 300.

2. The glass fiber filter paper as described in claim 1, characterized in that, The nonwoven fabric layer is a nonwoven fabric of varying density, with a basis weight of 10. -40 .

3. A method for preparing the glass fiber filter paper according to claim 1 or 2, characterized in that, Includes the following steps: At least three types of glass fibers, dispersant, and water are mixed evenly according to the formula to obtain at least three types of glass fiber slurries; the at least three types of glass fiber slurries are respectively formed into glass fiber paper films on non-woven fabric laid on a paper forming wire, and after pressing and initial drying, at least three dry paper films are obtained; the at least three paper films are released at the same speed, while the non-woven fabric on at least one intermediate paper film is removed, and then the at least three paper films are glued and laminated, and the adhesive is cured to obtain the glass fiber filter paper.

4. The method for preparing glass fiber filter paper as described in claim 3, characterized in that, During the glass fiber paper film forming process, the concentration of glass fiber is 0.0001 g / ml to 0.008 g / ml, and the forming screen speed is 4 m / min to 40 m / min.

5. The method for preparing glass fiber filter paper as described in claim 3, characterized in that, The pressing load is 5 N - 80 N; the initial drying temperature is 80℃ - 150℃.

6. The method for preparing glass fiber filter paper as described in claim 3, characterized in that, The sizing ratio is 5 wt%-10 wt% based on the mass of the three-layer paper film.

7. A filter material, characterized in that, Includes a filter layer, wherein the filter layer is made of glass fiber filter paper as described in any one of claims 1 or 2.

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