JP2019063751A - Filter material for automobile fuel - Google Patents

Abstract

To provide a filter material for automobile fuel which has performance of sufficiently capturing fine particles and achieves a long life.SOLUTION: There is provided a filter material for automobile fuel in which a prefilter layer formed of a reinforcement material formed of a synthetic resin and a long fiber spunlace non-woven fabric as an upstream side outermost layer, a main filter layer formed of a short fiber spunlace non-woven fabric, and a cover material formed of a long fiber non-woven fabric layer as a downstream side outermost layer are joined to each other integrally with each other, and porosity is 80-87%.SELECTED DRAWING: None

Description

  The present invention relates to an automotive fuel filter material in which a plurality of non-woven fabrics are laminated. More particularly, the present invention relates to an automotive fuel filter material for a suction filter used on the primary side of a fuel pump installed in an automotive fuel tank.

Conventionally, a filter (hereinafter, also referred to as "suction filter") used on the primary side of a fuel pump installed in an automobile tank is a woven fabric mesh, a long fiber nonwoven fabric represented by a spunbond nonwoven fabric or a meltblown nonwoven fabric, A filter material using a staple-punched non-woven fabric or a short-fiber non-woven fabric represented by a thermal bond non-woven fabric, etc. is used. These filter materials have a trapping performance of particles of about 5 to 50 μm, preferably 10 to 30 μm or more It has been required to be excellent in particle capture performance.
In recent years, the required performance has been raised from the higher performance of the injector, and the further higher capturing performance and the longer life are required.

Nonwoven fabrics produced by the conventional spunbond method, meltblowing method, electrospinning method, etc. are not necessarily uniform in fiber arrangement when viewed in a small area, and therefore lack in uniformity of fiber spacing, fabric weight, fiber diameter, air permeability There is a problem that the variation in the properties related to the filter performance such as is large. Such variations appear as performance variations such as capture performance and life as a filter material, so it is difficult to maintain stable filter performance in a small area of about 50 to 500 cm ² in filtration area, and as a suction filter It was considered unsuitable as a filter material to be used.

In order to solve such a problem, a means for reducing the particle trapping property of the filter material has been adopted, but as a means therefor, a spunbond non-woven fabric which becomes a non-woven fabric having a larger fiber diameter than a non-woven fabric produced by melt blowing method or the like. Spunlace nonwoven fabric is used as a filter material, and woven fabric is used as a filter material.
Although the service life of the filter material can be extended as compared with the filter material using a melt-blown nonwoven fabric in each means, the span of the required particle capturing performance can be obtained by using a spunbond nonwoven fabric, although the effect is obtained. It is necessary to perform processing in a later step, such as performing surface smoothing processing in a step after preparation of the bonded nonwoven fabric. In this case, as with synthetic long-fiber non-woven fabrics such as melt-blown non-woven fabrics, although the capture efficiency is high, the capture mode is surface filtration, and there is a problem that the filter medium surface is blocked early by particles and has a short life. .

With respect to the above problems, in Patent Document 1 below, by using a spunlace nonwoven fabric having a spunbond nonwoven fabric as an intermediate layer as a filter material, sufficient fine particles can be obtained as compared with the case where a woven fabric is used as an intermediate layer. It has been found that a long-life filter material can be obtained while maintaining the trapping performance, and by laminating a long-fiber spunlaced non-woven fabric, further longevity can be expressed.
However, according to the technology described in Patent Document 1, when fine particles are captured, the surface is finally clogged, and after an increase in a certain differential pressure, the differential pressure increases in an accelerating manner. Under high pressure conditions, it was not possible to obtain a satisfactory life.

Patent No. 5281719 Patent No. 4350193 Patent No. 4559667 gazette

  SUMMARY OF THE INVENTION In view of the problems of the prior art described above, the problem to be solved by the present invention is to provide a filter material for automobile fuel which has sufficient capturing performance of fine particles and achieves long life even under high pressure conditions. It is.

As a result of intensive studies and repeated experiments to solve the above problems, the present inventors form a graded graded structure of spunbonded nonwoven fabrics having different fiber diameters in which thermocompression bonding is released by processing as a prefilter layer. Conventional automobile fuel filter materials by laminating a spunlaced non-woven fabric having a collection property higher than that of the prefilter layer as the main filter layer, and making the porosity 80% to 87%. It has been found that a filter material for automobile fuels can be obtained which has a high fine particle capturing performance and a long life even under high pressure conditions as compared with the above, and the present invention has been completed.
That is, the present invention is as follows.

[1] A cover made of a reinforcing material made of a synthetic resin as the upstream outermost layer, a prefilter layer made of a long fiber spunlace nonwoven fabric, a main filter layer made of a short fiber spunlace nonwoven fabric, and a long fiber nonwoven fabric as the downstream innermost layer A filter material characterized in that the materials are integrally joined and the porosity is 80 to 87%.
[2] The main filter layer is composed of two or more short fiber spunlaced non-woven fabrics, the total weight of the main filter layer is 250 to 300 g / m ² , the air permeability is 10 to 20 ml / cm ² / sec, the fiber diameter is The filter material according to the above [1], which has an inclined structure of 2 to 15 μm and in which the fiber diameter decreases from the upstream side to the downstream side of the filter material.
[3] The prefilter layer is composed of three or more long fiber spunlace nonwoven fabrics, the fabric weight of the long fiber spunlace nonwoven fabric is 50 to 100 g / m ² , and the air permeability is 80 to 180 ml / cm ² / sec, The filter material according to the above [1] or [2], which has a fiber diameter of 9 to 15 μm and an inclined structure in which the air permeability and the fiber diameter decrease from the upstream side to the downstream side of the filter material.
[4] The filter according to any one of the above [1] to [3], wherein the total basis weight of the filter material is 500 to 700 g / m ² and the air permeability is 5 to 10 ml / cm ² / sec. Material.
[5] The filter material according to any one of the above [1] to [4], which is for automobile fuel.

  In the filter material for automobile fuel according to the present invention, bulky non-woven fabric having a sloped structure in which the fiber diameter decreases from upstream to downstream is laminated, and the porosity after integral bonding is adjusted to 80 to 87%. It is possible to form a cake layer on the surface layer while providing a gradient function of sequentially capturing particles different in size, and to extend the filter life.

It is a conceptual diagram which shows the integral joining method of the filter material of this embodiment. It is a flowchart which shows the process of a capture efficiency measurement. It is a flowchart which shows the single pass test used for lifetime evaluation. It is a welding pattern figure used for the example. It is a figure explaining the manufacture direction of the main layer nonwoven fabric used in the example.

Hereinafter, embodiments of the present invention will be described in detail.
The automotive fuel filter material of the present embodiment includes a reinforcing material made of a synthetic resin as the upstream outermost layer, a prefilter layer made of a long fiber spunlace nonwoven fabric, a main filter layer made of a short fiber spunlace nonwoven fabric, and a downstream innermost layer The cover material which consists of a long fiber nonwoven fabric layer is integrally joined, and the porosity is 80 to 87%.

The main filter layer of the present embodiment is preferably made of two or more layers of staple fiber spunlaced non-woven fabric, and the basis weight of the entire main filter layer is 250 to 300 g / m ² , and the air permeability is 10 to 20 ml / cm ² / sec The fiber diameter is 2 to 15 μm, and the fiber diameter has an inclined structure that decreases from the upstream side to the downstream side of the filter material. In addition, a long-fiber non-woven fabric may be used as an intermediate layer between the two-layer short-fiber spunlaced non-woven fabric, and the three layers may be integrated by spunlacing.

In the present specification, the term "integral bonding" broadly means bonding and integrating a plurality of non-woven fabrics and the like by thermocompression bonding or the like, and is not intended to be limited to a specific bonding method.
By making the fiber diameter into the above-mentioned configuration, it is possible to provide a gradient function in which the fiber diameter is changed in the thickness direction of the non-woven fabric and to hold fine particles of different particle diameters in each layer to extend the filter life. Become.
In the present specification, a short fiber spunlace non-woven fabric refers to a non-woven fabric in which short fibers are formed into a web and fibers are entangled by high pressure water flow, for example, carded web, random web, wet papermaking web etc. by high pressure columnar flow, A three-dimensional entangled nonwoven fabric can be mentioned. Above all, a wet ultrafine fiber non-woven fabric made into a wet paper-making web using ultra-fine short fibers and three-dimensional entangled by high pressure columnar flow is compared with synthetic long fiber non-woven fabric such as spun bond non-woven fabric and melt-blown non-woven fabric. It is preferable as a non-woven fabric for a suction filter from the viewpoint that physical properties that affect filter performance such as air permeability are uniform and the capture efficiency of fine particles is excellent.

Further explaining the inclined structure, when laminating three layers of nonwoven fabric A, nonwoven fabric B and nonwoven fabric C, they are laminated from the upstream side with nonwoven fabric A, nonwoven fabric B and nonwoven fabric C, and the fiber diameter is nonwoven fabric A> nonwoven fabric B> nonwoven fabric C Or the air permeability is in the relationship of nonwoven fabric A> nonwoven fabric B> nonwoven fabric C, or both.
However, it is not the limitation about an intermediate layer at the time of using a long fiber nonwoven fabric as an intermediate layer between two layers of short fiber spunlace nonwoven fabrics, and integrating three layers by spunlace processing.

  As a material of the long fiber non-woven fabric used as the short fiber and the intermediate layer of the short fiber spun lace non-woven fabric of the main filter layer, a thermoplastic resin is preferable in order to perform integral bonding. Examples of thermoplastic resins include nylon 6, nylon 66, copolyamide fibers, olefin fibers such as polyethylene, polypropylene and copolypropylene, and polyester fibers such as polyethylene terephthalate and copolyester. In these examples, it is preferable to use a polyester fiber or a polyamide fiber having a small swelling with respect to fuel oil and having a relatively easy handleability in lamination processing and the like.

The pre-filter layer of the present embodiment is preferably composed of three or more long fiber spunlace nonwoven fabrics, the fabric weight of the long fiber spunlace nonwoven fabric is 50 to 100 g / m ² , and the air permeability is 80 to 180 ml / cm ² / sec, the fiber diameter is 9 to 15 μm, and the air permeability and the fiber diameter have a sloped structure that decreases from the upstream side to the downstream side of the filter material.
The long fiber spunlaced non-woven fabric used for the prefilter layer of the present embodiment can be obtained, for example, by a known spunbond method. For example, it can be obtained by melt spinning to obtain a web of continuous filaments and partially thermocompression bonding with a pair of embossing rolls and a smoothing roll. It is necessary to make bulk of spunbonded non-woven fabric in the state of thermocompression bonded by breaking the thermocompression bonding by processing, and processing for the spunbonded non-woven fabric is a water jet processing method of injecting high pressure water flow, It is preferable to release the thermocompression bonding by a method such as needle punching.
In the spunbonded nonwoven fabric from which thermocompression bonding has been released by these processes, the fibers are uniformly arranged three-dimensionally and the voids inside the nonwoven fabric are increased, so that the diameter of the pores formed by the fiber entanglement is The effect of life extension can be obtained because the amount of internal particle trapping is increased while maintaining uniformity and high particle trapping performance.

The long fiber spunlaced non-woven fabric is laminated in one or more layers, preferably in three or more layers, and the fiber diameter decreases from the upstream side to the downstream side of the filter material, and the air permeability is from the upstream side of the filter material It is preferable to have a gradient structure that becomes smaller toward the downstream side, and to have a gradient function of sequentially capturing different particles, and the fiber diameter of each layer is 9 to 16 μm, the air permeability 110 to 300 ml / cm ² / sec, the fabric weight 50 to 100 g / l. It is preferable that it is m < ² > and the porosity 90% or more.

  Further explaining the inclined structure, when laminating three layers of nonwoven fabric A, nonwoven fabric B and nonwoven fabric C, they are laminated from the upstream side with nonwoven fabric A, nonwoven fabric B and nonwoven fabric C, and the fiber diameter is nonwoven fabric A> nonwoven fabric B> nonwoven fabric C Or the air permeability is in the relationship of nonwoven fabric A> nonwoven fabric B> nonwoven fabric C, or both.

  As a material of the long fiber spunlaced non-woven fabric of the pre-filter layer, a thermoplastic resin is preferable in order to perform integral bonding. Examples of thermoplastic resins include nylon 6, nylon 66, copolyamide fibers, olefin fibers such as polyethylene, polypropylene and copolypropylene, and polyester fibers such as polyethylene terephthalate and copolyester. In these examples, it is preferable to use a polyester fiber or a polyamide fiber having a small swelling with respect to fuel oil and having a relatively easy handleability in lamination processing and the like.

  Although the non-woven fabric generally improves the capture performance, which is an important performance for the filter material, by reducing the fiber diameter, it is in a trade-off relationship that the filter life becomes short. In general, when a non-woven fabric having a fiber diameter of 5 μm or less such as a melt-blown non-woven fabric is laminated, the life becomes short, and the performance becomes insufficient as a suction filter material. In addition, by increasing the fiber diameter, the life can be extended, but the capture performance is lowered, so that the performance is also insufficient as a suction filter material.

  Therefore, by laminating the prefilter layer having the life extension effect and the main filter layer having the supplementary performance, it is possible to make the life and the supplementary performance compatible.

  The innermost layer in the present embodiment is a layer disposed at the most downstream portion of the filter material, and the suction filter usually has a bag shape as shown in FIG. 2 of Patent Document 2 and FIG. 1 of Patent Document 3. No, in order to prevent the inner surface of the bag from coming into close contact and obstructing the flow of fuel, a space forming part is internally provided. Furthermore, such spacing forming parts are in contact with the surface of the most downstream part of the filter material with aggregate-like projections in order to always form the internal space properly. Therefore, there is a risk that fiber breakage may occur in the filter material in contact with the projection due to vibration or the like when the vehicle is traveling, and if this progresses, the broken fibers are released from the filter material and flow into the fuel pump to cause fuel It may lead to damage to the pump. In order to solve such a problem, by using a spunbond non-woven fabric or monofilament woven fabric as a cover material at the most downstream part of the filter material, it is possible to prevent fiber tearing caused by the contact between the suction filter and the filter material. Thus, a highly reliable filter material in terms of strength can be obtained.

  As a material of a cover material, in order to perform integral joining, a thermoplastic resin is preferable. Examples of thermoplastic resins include nylon 6, nylon 66, copolyamide fibers, olefin fibers such as polyethylene, polypropylene and copolypropylene, and polyester fibers such as polyethylene terephthalate and copolyester. In these examples, it is preferable to use a polyester fiber or a polyamide fiber having a small swelling with respect to fuel oil and having a relatively easy handleability in lamination processing and the like.

  The reinforcing material of the present embodiment is disposed at the most upstream portion of the filter material, and the bag-like outer surface is in close contact with the inner surface of the fuel tank at the most upstream portion of the filter material to inhibit the flow of fuel. In order to prevent the problem and to prevent the fibers used in the filter material from being broken or released by contact with the inner surface of the fuel tank, monofilament woven fabric, ordinary spunbonded non-woven fabric or the like can be laminated.

  As a material of a reinforcing material, in order to perform integral joining, a thermoplastic resin is preferable. Examples of thermoplastic resins include nylon 6, nylon 66, copolyamide fibers, olefin fibers such as polyethylene, polypropylene and copolypropylene, and polyester fibers such as polyethylene terephthalate and copolyester. In these examples, it is preferable to use a polyester fiber or a polyamide fiber having a small swelling with respect to fuel oil and having a relatively easy handleability in lamination processing and the like.

  The materials of the reinforcing material, the prefilter layer, the main filter layer, and the cover material are preferably all the same material in consideration of the processability at the time of integral bonding.

In the present embodiment, the reinforcing material, the pre-filter layer, the main filter layer, and the cover material are integrally joined by heat welding. As a method of integral joining, partial welding by ultrasonic welding is preferable. To explain using FIG. 1, the raw material (1) is sent out and the ultrasonic horn (2) is pressed against the pin roll (3) Only the pin portion of 3) is welded by ultrasonic waves.
Generally, adjustment of the thickness of the filter material after integral bonding includes adjustment by contact pressure between the ultrasonic horn and the pin roll, and adjustment by calendering after ultrasonic welding.
Moreover, as the pattern of partial welding, since the welded part does not function as a filter, a pattern in which the distances between welded parts are aligned at equal intervals like parallel type or regular triangle type is preferable from the viewpoint of dead area, It is preferable that a welding area ratio is 0.1 to 4.0%.
The pattern in which the distances between welds are arranged at equal intervals means that all the distances between partial welds (18) are equally spaced as shown in FIG.

As filter performance required for the filter material for suction filter, it is required to maintain capture efficiency of fine particles required from various performances of the connected fuel pump and sufficient filter life while maintaining capture efficiency. The filter performance of the filter material of this embodiment is preferably a differential pressure measured by a measurement method according to JIS-B-8356-8, in which the capture efficiency of fine particles with a particle diameter of 10 μm or more is 95% or more. The arrival time for the increase amount of 10 kPa is 30 minutes or more, and the arrival time for the increase amount of the differential pressure to 30 kPa is 60 minutes or more.
The filter material of the present embodiment uses a spunbond non-woven fabric from which thermocompression bonding has been released as a prefilter layer, uses a wet ultrafine fiber non-woven fabric as a main filter layer, and controls the porosity to 80% to 87%. A cake layer is formed by the filter residue on the surface of the outermost layer which is the most upstream portion, and under high pressure conditions while maintaining sufficient fine particle capture efficiency by the density gradient of the prefilter layer and the density gradient of the main filter layer. Filter life can be dramatically increased.

Hereinafter, the present invention will be specifically described by way of examples. The characteristics in the examples were measured by the following methods.
(1) Weight per unit area (g / m ² )
The sample of 100 mm × 100 mm was collected at seven points in the width direction and at four points in the length direction, the weight was measured, converted to g / m ² , and the average value was determined.

(2) Thickness (mm)
The thickness at a load of 100 g / cm ² was measured at five points using a measuring element: φ 16 by a method based on the measurement method defined in JIS-L-1913-2010, and the average value was determined.

(3) Void ratio (%)
From the basis weight and the thickness described above, the following formula:
(1-weight / 1000 ÷ specific gravity ÷ thickness) × 100
Calculated by The specific gravity of polyethylene terephthalate was 1.38. The porosity per unit area was determined, and it was shown by an average value of three or more places.

(4) Fiber diameter (μm)
The surface of the non-woven fabric was enlarged by a photomicrograph, the fiber diameter (thickness) was measured at 10 points, and the average value was determined.

(5) Permeability (ml / cm ² / sec)
Three points were measured with a flange type tester defined in JIS-L-1913-2010, and the average value was determined.

(6) Particle capture efficiency (%)
It measured by the simple method based on JIS-B8356-8 method. That is, as shown in FIG. 2, a dust obtained by mixing JIS 7 type dust in a proportion of 3 mg / L in JIS No. 2 light oil present in the dust liquid tank (6), stirring and uniformly dispersing, a dust tank while propeller stirrer using a stirrer (5) in the inner, passed through a filter holder (9) samples at a flow rate of 12ml / min / cm ² through a tube (8) using a metering pump (7), before and after passing The solution was collected in a collection bottle (10), and the particle size distribution of each solution was measured with a particle size distribution meter to determine the capture (collection) efficiency of 10 .mu.m particle diameter.
When measuring the particle size distribution, using Accusizer MODEL 780 / SIS manufactured by PSS as a measuring instrument, the number of particles of 10 μm was measured for the test solution before and after passing the sample. The capture efficiency is as follows:
Capture efficiency [%] = (1−number of particles on the outlet side / number of particles on the inlet side) × 100
Determined by

(7) Filter life It measured by the simple method based on JIS-B8356-8 method. That is, as shown in FIG. 3, JIS 8 type dust is added to JIS No. 2 gas oil in the gas oil tank (13) at a rate of 20 mg / L using a tube pump (7), and the gas oil is flowed at a flow rate of 150 ml / min. The filter life time was measured by passing the sample filter (9) and measuring the time (minutes) until the differential pressure rise measured by the pressure gauge (17) installed before and after the sample filter reaches 10 kPa and 30 kPa. .

  Table 1 below shows main layer nonwoven fabrics (main layer 1 and main layer 2) used in the examples and comparative examples, and their physical properties. The main layer non-woven fabric is produced by the method shown in FIG. 5, and the intermediate layer (24) is a spun bond non-woven fabric produced by a known spun bond method. The materials of the upstream layer (short fibers), the intermediate layer (24), and the downstream layer (short fibers) were all polyethylene terephthalate.

  The prefilter layer nonwoven fabric (pre-layer 1, pre-layer 2, pre-layer 3) used for the Example and the comparative example in the following Table 2 and those physical properties are shown. The materials of the pre-layer 1, the pre-layer 2 and the pre-layer 3 were all polyethylene terephthalate.

[Examples 1 to 3]
As shown in FIG. 1, the reinforcing material (the outermost layer), the prefilter layer (the prelayer), the main filter layer, and the cover material (the innermost layer) (collectively shown as the raw material (1)) are ultrasonically welded. Integrally bonded to obtain a filter material. By changing the ultrasonic welding conditions, in particular, by the contact pressure between the ultrasonic horn (2) and the pin roll (3), samples having different thicknesses (integral bonding joint (4)) were obtained. Processing conditions are shown in Table 3 below.

In the first to third embodiments, the following configuration and integral connection were performed in order:
・ Fiber diameter 150 μm, 45 mesh, plain weave monofilament fabric ・ Pre-layer 1
Pre-layer 2
Pre-layer 3
・ Main layer 1
・ Fiber diameter 13.5μm, 35g / m ² in basis weight, spunbonded nonwoven fabric

Comparative Examples 1 and 2
In Comparative Examples 1 and 2, the main layer 1 and the main layer 2 were used alone, respectively, and the filter performance of the single main filter layer was confirmed.

Comparative Example 3
In Comparative Example 3, the following configuration and integral bonding were performed in order:
・ Fiber diameter 70μm, 50 mesh, plain weave monofilament fabric ・ Pre-layer 1
Pre-layer 2
Pre-layer 3
・ Main layer 1
Fiber diameter: 13.5 μm, fabric weight: 25 g / m ² , spun bond non-woven fabric In Comparative Example 3, a prefilter layer is laminated on the main filter layer used in Comparative Example 1, and further, reinforcing material and cover material are used for ultrasonic welding. The filter performance of the integrated filter material was confirmed.

The welding patterns in Examples 1 to 3 and Comparative Examples 1 to 3 were all arranged in an equilateral triangle arrangement as shown in FIG.
The results are shown in Table 4 below.

  When Comparative Examples 1 and 2 are compared, when the fiber diameter is reduced, the supplementation efficiency is improved but the life tends to be reduced. In addition, in Comparative Examples 1 and 2, the time to reach 30 kPa after reaching 10 kPa is very short compared to Examples 1 to 3 with respect to the life. This is considered to be because in the comparative examples 1 and 2, the internal capture is finished and the surface of the filter medium is clogged.

  In Comparative Example 3, by stacking the pre-filter layer, high capture and long life were achieved as compared with Comparative Example 1. However, in Comparative Example 3, as compared with Examples 1 to 3, regarding the life, the time to reach 30 kPa after reaching 10 kPa as in the case of the main filter single layer is very short. In Comparative Example 3, the prefilter layer was laminated, and by increasing the density gradient as the whole of the filter material, the improvement of the supplementability and the increase in life were achieved, but the porosity of the prefilter layer is high, and the main filter When the layer is closed, it is considered to be in a state of being closed as a filter material.

On the other hand, in Examples 1 to 3, the same pre-filter layer and main filter layer as in Comparative Example 3 were laminated, and the porosity of the entire filter material was kept low, and the filter performance was confirmed. It was confirmed that when the porosity is reduced to 82% to 86%, a high capture and long life filter material can be obtained.
In Examples 1 to 3, the porosity of the pre-filter layer is lower than that of Comparative Example 3 by suppressing the porosity to a low level, and it is considered that a cake layer is formed in the pre-filter layer.
From the above results, it was found that it is necessary to adjust the porosity of the integrally joined filter material in order to achieve the desired filter performance.

  The present invention is a filter material for automobile fuel in which non-woven fabrics are laminated, and since the trapping property of fine particles is improved and the filter life is extended compared to the conventional one, a fuel pump installed in a fuel tank for automobile It can be suitably used as a filter material of a suction filter used on the primary side of

DESCRIPTION OF SYMBOLS 1 raw material 2 ultrasonic horn 3 pin roll 4 integral joining anti-5 stirrer 6 dust liquid tank 7 tube pump 8 tube 9 sample filter 10 collection bottle 11 magnet gear pump 12 clean up filter 13 light oil tank 14 flow meter 15 dust liquid tank 16 stirring pump Reference Signs List 17 pressure gauge 18 partial welded portion 19 sheet making process 20 water jet process 21 drying process 22 winding process 23 a short fiber slurry 23 b short fiber slurry 24 middle layer

Claims (5)

  A reinforcing material made of synthetic resin as the upstream outermost layer, a pre-filter layer made of long fiber spunlace non-woven fabric, a main filter layer made of short fiber spunlace non-woven fabric, and a cover material made of long fiber non-woven fabric as the downstream innermost layer A filter material which is bonded and has a porosity of 80 to 87%. The main filter layer is composed of two or more short fiber spunlace nonwoven fabrics, the total weight of the main filter layer is 250 to 300 g / m ² , the air permeability is 10 to 20 ml / cm ² / sec, and the fiber diameter is ² to 15 μm The filter material according to claim 1, wherein the filter material has a sloped structure in which the fiber diameter decreases from the upstream side to the downstream side of the filter material. The prefilter layer is composed of three or more layers of long fiber spunlace nonwoven fabric, the fabric weight of the long fiber spunlace nonwoven fabric is 50 to 100 g / m ² , the air permeability is 80 to 180 ml / cm ² / sec, and the fiber diameter is The filter material according to claim 1 or 2, wherein the filter material has an inclined structure of 9 to 15 μm, and the air permeability and the fiber diameter decrease from the upstream side to the downstream side of the filter material. The total basis weight of the filter material is is a 500~700g / m ^2, and air permeability is 5~10ml / cm ² / sec, the filter material according to any one of claims 1 to 3.   The filter material according to any one of claims 1 to 4, which is for automobile fuel.

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