JPH11172564A - Laminated nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain laminated nonwoven fabric with excellent mechanical strength in addition to maintaining necessary heat treatment performance compared to nonwoven fabrics composed of conventional fibers with sheath/core structure. SOLUTION: This laminated nonwoven fabric has an intermediate 1st layer 11 and a 2nd layer 12 and 3rd layer 13 laminated on one side and the other side of the 1st layer 11, respectively; wherein the 1st layer 11 consists of a 1st nonwoven web, the 2nd layer 12 comprises conjugate fibers each composed of high-melting component and low-melting component, and the 3rd later 13 is made up of a 4th layer 14 comprising conjugate fibers each composed of high-melting component and low-melting component and 5th layer 15 comprising fibers made from a resin higher in melting point than the low-melting component of the fiber constituting the 4th layer 14; the 4th layer 14 is sandwiched between the 1st layer 11 and the 5th layer 15; the above-mentioned respective layers are mutually integrated through thermobonding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a laminated nonwoven fabric,
In particular, the present invention relates to a laminated nonwoven fabric suitable for producing a filter material, a bag, or the like by a heat bonding process.

[0002]

2. Description of the Related Art Conventionally, products such as filter materials and bags are manufactured from nonwoven fabrics. In such products, the required physical properties required for the product,
It is necessary to use a material that has both the strength required for the product. For example, a filter material is required to have a required filter performance and a predetermined strength necessary for a filter material as a product. In addition, bags, such as envelopes, are required to have the same strength and to have thermal adhesiveness for forming the bags.

As described above, nonwoven fabrics used for special applications are generally required to satisfy various performances.

[0004]

Some non-woven fabrics are required to have both thermal adhesiveness and thermal workability and required strength, depending on the use. As a material that satisfies such demands, there has been known a material in which a core portion is formed of an ester-based polymer and a sheath portion is formed of a core-sheath structure fiber formed of an olefin-based polymer to form a nonwoven fabric. . With this configuration, the ester-based polymer in the core generally has a higher melting point than the olefin-based polymer in the sheath. When performed, only the low-melting olefin polymer in the sheath contributes to the pressure welding, and at that time, the high-melting ester polymer in the core is not adversely affected by heat, thus maintaining the required filament strength. It becomes possible to do. Therefore, the nonwoven fabric can be formed into a nonwoven fabric by the heat bonding treatment, and the nonwoven fabric can have sufficient strength after the treatment.

An object of the present invention is to obtain a laminated nonwoven fabric which is more excellent in strength while maintaining the required heat treatment performance as compared with a conventional nonwoven fabric formed of fibers having a core-sheath structure. I do.

[0006]

In order to achieve this object, the present invention provides an intermediate first layer, and second and third layers laminated on one side and the other side of the first layer. And
The first layer is composed of a first nonwoven web, and the second layer is a composite fiber having a high melting point component and a low melting point component having a lower melting point than the high melting point component. The third layer has a structure in which a fourth layer and a fifth layer are further laminated, and the fourth layer has a high melting point. A third nonwoven web formed of fibers of a composite structure having a component and a low melting point component having a lower melting point than the high melting point component, wherein the fifth layer is a fourth layer And a fourth nonwoven web formed of fibers made of a resin having a higher melting point than the low melting point component of the fibers constituting the first layer. The fourth layer is sandwiched between a first layer and a fifth layer. So that the layers are integrated with each other by thermal bonding.

With such a configuration, the second layer and the fourth layer are formed of fibers of a composite structure having a high melting point component and a low melting point component having a lower melting point than the high melting point component. Therefore, it is possible to impart the required heat bonding performance and strength to the nonwoven fabric. Further, since the fifth layer is formed of a fiber made of a resin having a higher melting point than the low melting point component of the fiber constituting the fourth layer, the second layer and the fourth layer are formed as described above. Even if the low-melting-point component of the constituent fiber is subjected to thermal bonding treatment or thermal processing, the constituent fiber of the fifth layer is not adversely affected by heat, and therefore, the second layer and the fourth layer are not affected. Contributes to the strength of the nonwoven fabric at least as high as or higher than the high melting point component of the constituent fibers of the layer. For this reason, while maintaining the required heat treatment performance, it is possible to obtain excellent strength. Also,
By configuring the first layer with a non-woven web of special performance such as a filter material, the entire laminated nonwoven fabric can be made to conform to the characteristics of the first layer.

Further, the present invention provides a nonwoven fabric in which one layer and the other layer are laminated, wherein one layer comprises a high melting point component,
A fiber formed of a fiber having a composite structure having a low melting point component having a lower melting point than the high melting point component, and the other layer is made of a resin having a higher melting point than the low melting point component of the fiber constituting one layer. And one of these layers and the other layer are integrated with each other by thermal bonding.

According to such a configuration, one of the layers is
Since it is formed of a fiber having a composite structure having a high melting point component and a low melting point component having a lower melting point than the high melting point component, it is possible to impart the required heat bonding performance and strength to the nonwoven fabric. is there. Not only that, since the other layer is formed of fibers made of a resin having a higher melting point than the low melting point component of the fibers constituting one layer, the structure of one layer is not affected by heat. Strength can be imparted to the nonwoven fabric equal to or higher than the high melting point component of the fiber.
Therefore, similarly, the laminated nonwoven fabric excellent in strength can be obtained while maintaining the required heat treatment performance.

[0010]

FIG. 1 schematically shows the cross-sectional structure of a laminated nonwoven fabric according to a first embodiment of the present invention.
Here, reference numeral 11 denotes a first layer, and a second layer 12 and a third layer 13 are laminated on one surface and the other surface of the first layer 11, respectively. Further, the third layer 13 has a configuration in which a fourth layer 14 and a fifth layer 15 are stacked, and the fourth layer 14 is in contact with the first layer 11.

The first layer 11 is composed of a nonwoven web having the performance originally required for this laminated nonwoven fabric.
For example, when the laminated nonwoven fabric is used as a filter, the first layer 11 is formed of a nonwoven web having required filter characteristics. When the laminated nonwoven fabric is used as a bag such as an envelope, the first layer 11 is formed of a nonwoven web having a strength suitable for the bag, for example, a synthetic fiber composed of an ester-based or amide-based polymer component. It is constituted by a non-woven web formed in this manner.

The second layer 12 is made of, for example, a non-woven web formed of long fibers having a core-sheath structure.
This long fiber is formed of a polymer component having a lower melting point at the peripheral sheath portion than at the central core portion.

Each of the polymers for forming the core component and the sheath component has a fiber-forming property and can be melt-spun using a conventional melt-spinning apparatus. Examples of the combination of the polymer of the core component and the polymer of the sheath component include an amide type and an ester type, an ester type and an olefin type, and an amide type and an olefin type. Among them, amide polymers include nylon 6,
Polyamides such as nylon 46, nylon 66 or nylon 610 are polyester polymers such as polyethylene terephthalate, polybutylene terephthalate or a copolymer of diol and terephthalic acid / isophthalic acid. And polyolefins such as polypropylene, high-density polyethylene, linear low-density polyethylene and ethylene / propylene copolymer. For example, those using polyethylene terephthalate for the core component and polyethylene for the sheath component are particularly suitable. These polymer components may be added with additives such as ordinary matting agents, heat stabilizers, pigments or polymer crystallization accelerators.

In this long fiber, as described above, it is necessary that the melting point of the polymer component of the surrounding sheath portion is lower than that of the polymer component of the central core portion. Is preferred. The melting point of the polymer as used herein is obtained by using a differential calorimeter DSC-2 manufactured by Perkin Elmer and measuring the amount of the sample at about 5 mg and the scanning speed at 20 ° C./min according to the manual of the apparatus. It is determined from the DSC curve. When the difference in melting point of the polymer component between the sheath portion and the core portion was less than 30 ° C., at least partially hot pressing was performed between the fibers of the web by a heating roll for integration of the laminated web as described below. At times, the polymer component on the high melting point side is thermally degraded, and the strength of the nonwoven fabric is reduced.

Instead of the above-mentioned core-sheath structured long fiber, a long fiber having a side-by-side structure in which a high melting point component and a low melting point component are arranged in parallel, or a composite long fiber having another configuration may be used. The same operation and effect can be exhibited.

The fourth layer 14 is preferably formed of a nonwoven web formed of, for example, long fibers having a core-sheath structure similar to the second layer 12. As a result, the second layer 12 and the fourth layer 14 formed of the same long fibers having the same core-sheath structure are arranged on both surfaces of the first layer 11.

The fifth layer 15 needs to be formed of long fibers made of a resin having a higher melting point than the sheath of the long fibers of the core-sheath structure constituting the fourth layer 14. As such a resin, that is, a polymer component, the same polymer component as that of the core of the fiber having a core-sheath structure constituting the fourth layer 14 can be exemplified. Specifically, the polymer component of the long fiber constituting the fifth layer 15 has a melting point higher by 20 ° C. or more than the melting point of the polymer component of the sheath portion of the fiber having the core-sheath structure constituting the fourth layer 14. It is preferable to have This melting point difference is 20
When the temperature is lower than 0 ° C., for example, when a nonwoven fabric is subjected to thermal bonding as described below to produce a bag, the melting point of the polymer constituting the fiber between the heater side and the non-heater side of the bag making machine, that is, the bonding surface side. The difference is small, and the problem that the polymer melts and adheres to the heater when the heating / compression treatment is performed at a high temperature and the product quality and the yield are reduced easily occurs.

Accordingly, specifically, as the polymer component of the sheath portion of the long fiber constituting the fourth layer 14, particularly preferred are high-density polyethylene, linear low-density polyethylene, polypropylene or ethylene / propylene copolymer. Examples include olefin-based polymers such as coalesced copolymers and copolymers of diol and terephthalic acid / isophthalic acid. At that time, particularly preferred as the polymer component of the core portion of the same long fiber is an ester polymer or an amide polymer such as polyethylene terephthalate or polybutylene terephthalate. Further, as the polymer component of the long fiber constituting the fifth layer 15, an ester polymer such as polyethylene terephthalate or polybutylene terephthalate or an amide polymer like the polymer component of the core of the fourth layer 14 is preferable. It is a system polymer.

For example, the long fibers constituting the fifth layer 15 are formed of polyethylene terephthalate, the cores of the long fibers constituting the fourth layer 14 are also formed of polyethylene terephthalate, and the fourth layer 14 is formed of polyethylene terephthalate. It is particularly preferable that the sheath of the constituent long fibers is formed of polyethylene.

Further, for example, if the long fibers constituting the fifth layer 15 are formed of polyethylene terephthalate and the core of the long fibers constituting the fourth layer 14 are formed of copolymerized polyethylene, The melting point of the long fibers of the fifth layer 15 is higher than that of the core of the long fibers of the layer 14, and the function of imparting the strength of the nonwoven fabric by the fifth layer 15 can be further clarified. At this time, the fourth
The sheath portion of the long fiber constituting the layer 14 is preferably made of a polyolefin such as polyethylene or polypropylene.

As described above, the core-sheath type is the most suitable as the composite form of the long fibers constituting the second layer 12 and the fourth layer 14. However, a high melting point component may be exposed on the surface of the conjugate fiber, such as a side-by-side type. In the case of the side-by-side type, as each polymer component, those having compatibility with each other are selected.
It is preferable to prevent separation of the high melting point component and the low melting point component. The cross-sectional shape is usually a circular cross-sectional shape, but may be various irregular cross-sectional shapes such as a flat type or a polygonal type or a hollow cross-sectional shape. Further, the compounding ratio of the high melting point component and the low melting point component is not particularly limited, but from the viewpoint of balancing thermal bonding between fibers by the low melting point component and retention of nonwoven fabric strength by the high melting point component. If
Extremely unbalanced ones are not preferred. Usually, the ratio (weight ratio) of the high melting point component to the low melting point component is (low melting point component) /
(High melting point component) = 1/4 to 2/1.

The fineness of the fibers constituting each layer is not particularly limited. However, when it is extremely small, a unique hand is exhibited, but productivity is lowered, which is not preferable. When the size is large, the laminated nonwoven fabric is not preferable because the flexibility is lowered and the feeling is deteriorated. Usually, it is good to be about 2 to 10 denier.

The laminated nonwoven fabric of the present invention has the second layer 1 on one side.
2 and the other surface is formed by a fifth layer. That is, in the laminated nonwoven fabric of the present invention, on one surface of the nonwoven fabric, that is, the surface where the second layer 12 is exposed, the polymer component of the low melting point component, which is a component of the composite long fiber, is present. The other surface, that is, the surface where the fifth layer 15 is exposed, contains a polymer component having a higher melting point than the low melting point component. Therefore, even when the web roll is partially hot pressed between the fibers of the web by a heating roll to form a laminated nonwoven fabric, the fifth layer 15
Since the polymer component having a high melting point does not deteriorate due to heat, there is an advantage that the strength of the obtained nonwoven fabric does not decrease. Further, when the laminated nonwoven fabric is subjected to a thermal bonding process to produce a bag such as an envelope, for example, if the second layer 12 is subjected to a thermal bonding process with the side of the second layer 12 as a bonding surface, sufficient thermal bonding is performed even at a low processing temperature. As a result, the polymer does not melt and adhere to the heater, thereby lowering product quality and yield.

Next, a method for producing the laminated nonwoven fabric of the present invention will be described. For example, the fourth layer 14 and the fifth layer 15
Are temporarily integrated in advance by a partial thermal pressure welding process to form a third layer 13, and then the third layer 13 and the second layer 12 are combined with one side of the first layer 11 and the other. The laminated nonwoven fabric of the present invention can be obtained by laminating on a surface and performing full-scale thermal pressure contact. Alternatively, depending on the use of the laminated nonwoven fabric, the fifth layer 15 and the fourth layer 14 may be used as described above.
It is also possible to obtain a finished product at the stage where the components are integrated by partial heat welding.

More specifically, the constituent fibers of the fourth layer and the constituent fibers of the fifth layer are melt-spun from a melt spinning apparatus, and both spun long fibers are air-spun respectively disposed downstream of the melt spinning apparatus. After being taken up by a sucker, or after being taken up by a take-up roll, after being continuously stretched between a take-up roll and a stretching roll disposed downstream of the take-up roll, the drawer is downstream or drawn from the air sucker. Spreading is performed by a spreader arranged downstream of the roll in the web advancing direction, and both long fibers are ejected and deposited from an ejection hole arranged below the spreader to form a laminated web. I do. The fifth layer 15 and the fourth layer are temporarily integrated by partially heat-pressing the laminated web to form the third layer 13.

In the above-mentioned steps, the constituent fibers of the fourth layer and the constituent fibers of the fifth layer are individually melt-spun and formed into sheets by a conventional spunbonding method. By performing the partial thermocompression bonding, the fourth layer 14 and the fifth layer 15 can be similarly integrated to form the third layer 13.

At this time, by disposing the fifth layer 15 composed of only the high melting point component on the hot embossing roll side and disposing the fourth layer 14 on the flat cooling roll side, the completed laminated web is heated. Therefore, it can be prevented from being wound around a roll. As described above, at this stage, the fifth layer 1
It is also possible to completely integrate the fifth and fourth layers 14 into a finished product.

The first layer 11 and the second layer 12 are similarly formed as webs, and then these webs are integrated as shown in FIG. That is, in FIG. 2, 21 is a hot embossing roll, 22 is a flat cooling roll, and a third layer 13 is provided between these rolls 21 and 22.
And the first layer 11 and the second layer 12 are fed in a stacked state. At this time, as shown in the figure, the third layer 13, that is, the fifth layer 15 is in contact with the hot embossing roll 21, and
By feeding the second layer 12 so that the second layer 12 is in contact with the cooling roll 22, it is possible to prevent the laminated nonwoven fabric that is completed in the same manner as described above from being wound around the roll due to heat.

When a filter is manufactured from the completed laminated nonwoven fabric, a filter of a desired form can be obtained by pleating the laminated nonwoven fabric obtained by integrating the nonwoven webs. it can.
At this time, when the third layer 13 is formed by laminating the fifth layer 15 and the fourth layer 14 and performing hot embossing, as shown in FIG. 2, the laminated nonwoven fabric is formed by hot embossing. By controlling the thermal pressure contact ratio when the whole is integrated, desired air permeability can be imparted to the obtained filter.

When a bag such as an envelope is manufactured from the laminated nonwoven fabric, thermal processing is performed at a controlled temperature to change the heat shrinkage of the second layer 12 and the third layer 13.
By thermally shrinking the second layer 12 to a greater extent, the second layer 12 becomes the innermost and the fifth layer 15 becomes the outermost, as schematically shown in FIG. Molding. Then, as shown in FIG. 4, this cylindrical body is bent to form the second layer 12 on the inner surface side containing the low melting point component.
By performing heat sealing using the method, necessary portions can be sealed.

[0031]

EXAMPLES In the following examples, measurement of various characteristic values was carried out.
It carried out by the following method. (1) Melting point (° C.): Measured using a differential scanning calorimeter DSC-2 manufactured by Perkin Elmer Co. under the condition of a temperature rising rate of 20 ° C./min. Melting point. (2) Intrinsic viscosity of polyester: A mixture of phenol and ethane tetrachloride was used as a solvent, and 0.5 g of a sample was dissolved in 100 cc of the solvent. (3) Melt index of polyethylene (g / 10
Min): Measured according to the method described in ASTM-D-1238 (E). (4) Non-woven fabric weight (g / m ² ): A total of 10 sample pieces of 10 cm long × 10 cm wide were prepared from a sample in a standard state.
After reaching the equilibrium moisture, the weight (g) of each sample piece was weighed, and the average value of the obtained values was converted into a unit area (m ² ) to obtain a basis weight (g / m ² ). (5) Tensile strength (kg / 5 cm width) and tensile elongation (%) of nonwoven fabric: Measured according to the method described in JIS-L-1096A. That is, the sample length is 15 cm and the sample width is 5
cm of the nonwoven fabric in the machine direction (MD) and the direction perpendicular to it (CD), and 10 points in each of the sample directions. (Tensilon UTM-4-1-100 manufactured by Toyo Baldwin Co., Ltd.) was used, and the sample was stretched at a gripping interval of 10 cm and a tensile speed of 10 cm / min.
The average value of the obtained load values at cutting (kg / 5 cm width) was defined as the tensile strength (kg / 5 cm width), and the average value of the elongation rate at cutting (%) was defined as the tensile elongation (%). . (6) Tear strength (kg) of nonwoven fabric: JIS-L-109
The measurement was performed according to the method described in 6D. That is, 6.3
Five points of a sample piece of × 10 cm were prepared in the machine direction (MD) of the nonwoven fabric, and 2 cm perpendicular to the center of both grips of the sample piece using an Elmendorf-type tensile tester (manufactured by Daiei Kagaku Seiki Co., Ltd.).
The remaining 4.3 cm was torn in the machine direction (MD) of the nonwoven fabric, and the average value of the obtained load values was taken as the tear strength (kg). (7) Delamination strength (g / 5 cm width): sample length is 15c
m, a total of three sample pieces each having a sample width of 5 cm were prepared, and for each sample, in the longitudinal direction of the nonwoven fabric, a constant-speed elongation type tensile tester (Tensilon UTM-4-1- manufactured by Toyo Baldwin Co., Ltd.)
100), the end of one web and the end of the other web in the composite nonwoven fabric having a laminated structure are gripped by upper and lower chucks, and a 5 cm length is forcibly peeled at a peeling speed of 5 cm / min. The average value of the obtained load values was defined as the delamination strength (g / 5 cm width). (8) Air permeability (cc / cm ² / sec): JIS-L-10
The measurement was carried out according to the method described in 96A. That is, 20
After preparing five sample pieces of × 20 cm and attaching the sample piece to one end of the cylinder using a Frazier-type tester (APS-360 manufactured by Daiei Kagaku Seiki Co., Ltd.), the tilt type barometer was 1.27 cm in water column. Adjust the suction pump to indicate the pressure of
From the pressure indicated by the vertical barometer at that time and the type of air hole used, the value of the amount of air was determined from the table attached to the tester, and the average value of the determined amount of air was calculated as the air permeability (cc / cc).
cm ² / sec).

Example 1 A laminated nonwoven fabric was manufactured using only the fourth layer and the fifth layer. That is, a spinneret having a spinning hole group consisting of 64 single-component spinning holes and a spinning hole group consisting of 64 core-sheath composite spinning holes was used.
Then, a long fiber with a circular cross section of 3 denier fineness made of polyethylene terephthalate having an intrinsic viscosity of 0.70 is spun out of the single-component spinning hole, and polyethylene having the same core component as the single component is spun out of the core-sheath composite spinning hole. Terephthalate, sheath component made of high-density polyethylene having a nominal melt index of 20 g / 10 min, fineness of 3 denier, core / sheath weight ratio of 1
/ 1 core-sheath composite long fiber was spun out. The spun long fiber group was picked up by a plurality of independent jets, respectively, spouted from a plurality of ejection holes, and a web composed of both long fibers was piled up and deposited, and conveyed by a normal nonwoven web conveyance device. .

Then, the deposit was passed through a hot-pressing device equipped with a hot embossing roll and a flat cooling roll to integrate the webs. At this time, the web composed of the long fibers having a circular cross section was brought into contact with the hot emboss roll, and the web composed of the core-sheath composite long fibers was brought into contact with the flat cooling roll.

As a result, a laminated nonwoven fabric was obtained. The physical properties of this laminated nonwoven fabric were as follows. Weight 35 (g / m ² ) Tensile strength (MD) 10.5 (g / 5 cm width) Tensile strength (CD) 3.5 (g / 5 cm width) Tensile elongation (MD) 16 (%) Tensile elongation ( CD) 22 (%) Tear strength (MD) 0.21 (kg) Peel strength 55 (g / 5 cm width) Air permeability 215 (cc / cm ² / sec)

Example 2 A laminated nonwoven fabric having a sectional structure shown in FIG. 1 was manufactured. That is, the laminated nonwoven fabric obtained in Example 1, a nonwoven web for constituting a filter material, and a nonwoven web formed of the same core-sheath composite long fiber as that of Example 1 were used. In the state of being laminated as shown in FIG.
These webs were integrated with each other by passing through a hot-pressing device equipped with a hot embossing roll and a flat cooling roll. At this time, the web made of the long fibers having a circular cross section in the laminated nonwoven fabric obtained in Example 1 was brought into contact with the hot embossing roll, and the web made of the same core-sheath composite long fibers as in Example 1 was flattened. It was brought into contact with a cooling roll.

The obtained laminated nonwoven fabric has a sheath portion of a core-sheath long fiber in which a low melting point component is disposed on one side and the other side of a nonwoven web for forming a filter material. Was subjected to a heat treatment after being in contact therewith, and thus had excellent peeling resistance between layers.

Further, the obtained laminated nonwoven fabric was pleated by heat to produce a filter element. Then, a desired filter material was obtained by housing the filter element inside the frame. This filter material had the expected filter performance. In addition, since the core portion of the core-sheath structured long fiber and the long fiber having a circular cross-section are both high melting point components, and these are not adversely affected by heat during thermal processing, the obtained filter material is required. It was powerful.

[0038]

As described above, according to the present invention, the second layer and the fourth layer each have a composite structure fiber having a high melting point component and a low melting point component having a lower melting point than the high melting point component. , The required heat bonding performance and strength can be imparted to the nonwoven fabric. Further, since the fifth layer is formed of a fiber made of a resin having a higher melting point than the low melting point component of the fiber constituting the fourth layer, the second layer and the fourth layer are formed as described above. Even if the low-melting-point component of the constituent fiber is subjected to thermal bonding treatment or thermal processing, the constituent fiber of the fifth layer is not adversely affected by heat. The constituent fibers can contribute to the strength of the nonwoven fabric equal to or higher than the high melting point component of the constituent fibers of the second layer and the fourth layer. For this reason, a laminated nonwoven fabric excellent in strength can be obtained while maintaining the required heat treatment performance. In addition, by configuring the first layer with a nonwoven web having a special performance such as a filter material, the entire laminated nonwoven fabric can be made to conform to the characteristics of the first layer.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a schematic structure of a laminated nonwoven fabric according to an embodiment of the present invention.

FIG. 2 is a view for explaining a manufacturing process of the laminated nonwoven fabric of FIG. 1;

FIG. 3 is a view for explaining a step of manufacturing a bag using the laminated nonwoven fabric of FIG. 1;

FIG. 4 is a view for explaining a step subsequent to FIG. 3;

[Explanation of symbols]

 11 first layer 12 second layer 13 third layer 14 fourth layer 15 fifth layer

Claims (10)

[Claims] 1. A semiconductor device comprising: an intermediate first layer; and a second layer and a third layer laminated on one side and the other side of the first layer, wherein the first layer is a first layer. A second nonwoven fabric formed of a fiber having a composite structure having a high melting point component and a low melting point component having a lower melting point than the high melting point component. The third layer has a configuration in which a fourth layer and a fifth layer are further laminated, and the fourth layer has a high melting point component and a higher melting point component. A third nonwoven web formed of a fiber having a composite structure having a low melting point component having a low melting point, wherein the fifth layer is formed from a low melting point component of the fiber constituting the fourth layer. Also comprises a fourth nonwoven web formed of fibers made of a resin having a high melting point, wherein the fourth layer is sandwiched between a first layer and a fifth layer. Wherein the respective layers are integrated with each other by thermal bonding. 2. The laminated nonwoven fabric according to claim 1, wherein the second layer and the fourth layer are formed of the same material. 3. The second layer and the fourth layer, wherein the high melting point component is formed of an ester polymer and the low melting point component is formed of an olefin polymer. The laminated nonwoven fabric according to claim 2. 4. The laminated nonwoven fabric according to claim 3, wherein the fibers of the fifth layer are formed of an ester polymer. 5. A fiber having a core-sheath structure in which a high melting point component constitutes a core portion and a low melting point component constitutes a sheath portion, or a low melting point component and a high melting point component. 5 is formed of fibers having a side-by-side structure arranged in parallel with each other.
13. The laminated nonwoven fabric according to the above item. 6. The laminated nonwoven fabric according to claim 1, wherein the first layer is formed of a filter material. 7. A nonwoven fabric in which one layer and another layer are laminated, wherein one layer has a high melting point component and a low melting point component having a lower melting point than the high melting point component. The other layer is formed of fibers made of a resin having a higher melting point than the low melting point component of the fibers constituting the one layer, and the one layer and the other layer are mutually bonded by thermal bonding. A laminated nonwoven fabric characterized by being integrated. 8. The fiber according to claim 7, wherein one of the layers has a core-sheath composite structure having a core made of a high-melting component and a sheath made of a low-melting component. The laminated nonwoven fabric according to the above. 9. The laminated nonwoven fabric according to claim 8, wherein the core of the fiber in one layer is formed of an ester polymer and the sheath is formed of an olefin polymer. . 10. The laminated nonwoven fabric according to claim 9, wherein the fibers of the other layer are formed of an ester polymer.