JP7104963B2 - Laminated continuous fiber nonwoven fabric and method for producing the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a civil engineering material composed of a laminated long-fiber nonwoven fabric and a method for producing the same, and in particular, the laminated long-fiber material is resistant to deformation due to compression, maintains the voids of the nonwoven fabric, and can maintain high air permeability and water permeability. The present invention relates to a civil engineering material composed of nonwoven fabric and a manufacturing method thereof.

Long-fiber nonwoven fabrics have conventionally been used for various purposes. Among long-fiber non-woven fabrics, non-woven fabrics made of polyester long fibers have higher rigidity than synthetic fibers other than polyester, and are therefore used, for example, as supports to be laminated and bonded to filter materials.

Patent Document 1 discloses a nonwoven fabric used as a filter support, which is composed of continuous polyester fibers composed of a low-melting component and a high-melting component, and is partially thermocompressed. Nonwoven fabrics having high strength and excellent rigidity are disclosed.

However, since the nonwoven fabric of Patent Literature 1 is partially thermocompression-bonded to improve its rigidity, the nonwoven fabric itself is crimped to crush the voids between the fibers.
Japanese Patent Application Laid-Open No. 2003-275519 (Claims)

The inventor of the present invention aims to obtain a nonwoven fabric having a high basis weight and air permeability, and having excellent rigidity while maintaining the interfiber voids, instead of partially heat-pressing to crush the interfiber voids to exhibit rigidity. investigated.
On the other hand, the present inventor has developed a polyester nonwoven fabric having a special cross-sectional shape (Japanese Patent Application Laid-Open No. 2013-76182). This is a nonwoven fabric having polyester long fibers as constituent fibers, and is characterized in that the cross-sectional shape of the polyester long fibers is a substantially Y4 shape that is connected vertically and horizontally at the lower end of a substantially Y shape. be. Such a polyester nonwoven fabric is composed of long fibers with a unique cross-sectional shape, and thus has a characteristic of high rigidity.

Then, when the above-mentioned long fibers with a unique cross-sectional shape were used to form a nonwoven fabric by a specific means, it was found that a non-woven fabric was obtained that was difficult to compress in the thickness direction and could maintain inter-fiber voids, and a patent application was filed. (Japanese Patent Application No. 2016-224280). The present invention utilizes the aforementioned patent application, and an object of the present invention is to obtain a civil engineering material that has high basis weight and air permeability, and that is resistant to compression in the thickness direction while maintaining interfiber voids.

形状（以下、「略Ｙ４形状」という。）で、単繊維繊度が１２デシテックス以上であり（ただし、１３．２デシテックス以下を除く。）、
細繊度ウェブは、単繊維繊度が８デシテックス未満であり、
積層長繊維不織布の目付が１００ｇ／ｍ^２以上、１００ｇｆ／ｃｍ^２荷重時の嵩密度が０．１３０ｇ／ｃｃ以下であることを特徴とする土木資材を要旨とする。
That is, the present invention is a civil engineering material that is buried in the soil or laid in contact with the soil, and the civil engineering material is either a ground reinforcement material, a rainwater separation material, or a drainage material,
The civil engineering material is composed of a large fineness web having long fibers having a large single fiber fineness as constituent fibers and a fine fineness web having long fibers having a single fiber fineness smaller than that of the large fineness web. Consists of needle-punched laminated long-fiber nonwoven fabric,
The large fineness web and the fine fineness web are formed by three-dimensionally entangling the constituent fibers and stacking them together.
The thick fineness web has polyester long fibers as constituent fibers, and the cross-sectional shape of the polyester long fibers is substantially Y-shaped and connected vertically and horizontally at the lower end.

Shape (hereinafter referred to as “substantially Y4 shape”) and single fiber fineness of 12 decitex or more (excluding 13.2 decitex or less) ,
The fine fineness web has a single fiber fineness of less than 8 decitex,
A civil engineering material characterized by a laminated filament nonwoven fabric having a basis weight of 100 g/m ² or more and a bulk density of 0.130 g/cc or less under a load of 100 gf/cm ² .

In the present invention , the laminated long-fiber nonwoven fabric includes a large fineness web whose constituent fibers are long fibers having a large single fiber fineness, and a fine fineness web whose constituent fibers are long fibers whose single fiber fineness is smaller than that of the large fineness web. and are laminated.

First, the thick fineness web that constitutes long fibers having a large single fiber fineness will be described. The thick fineness web is composed of polyester long fibers, and the polyester long fibers have a characteristic cross-sectional shape of the fibers. This cross-sectional shape has four substantially Y-shapes as shown in FIG. The lower end 1 of the substantially Y shape is connected vertically and horizontally to form a substantially Y4 shape as shown in FIG. This substantially Y4 shape has four concave portions 2, eight convex portions 3, and four small concave portions 4, so that it is excellent in bulkiness. In addition, the four concave portions 2 easily trap dust and the like, and are excellent in filter performance and dust trapping performance. In addition, the substantially +-shaped portion 5 in the center and the four substantially V-shaped portions 6 connected to the ends of the substantially +-shaped portion 5 provide high rigidity. In other words, the combination of the substantially +-shaped portion 5 and the substantially V-shaped portion 6 having high rigidity, rather than a simple deformed shape such as a hexagon or a Y-shape, provides higher rigidity.

The polyester long fibers constituting the large fineness web may be made of one type of polyester, or may be made of a combination of a low-melting polyester and a high-melting polyester. When it is composed of one type of polyester, it is preferably composed of polyethylene terephthalate because of its excellent fiber strength and thermal stability. In the case of a combination of low-melting polyester and high-melting polyester, the substantially V-shaped portion 6 of the cross-sectional shape of the polyester long fiber is formed of low-melting polyester, and the substantially +-shaped portion 5 is formed of high-melting polyester. A composite type is preferable. When using composite type polyester long fibers, only the low melting point polyester is softened or melted during temporary pressure bonding for shape retention before the needle punching process described later, and the low melting point polyesters are temporarily thermally bonded to each other. It is better to have a degree.

The single fiber fineness of the polyester long fibers constituting the large fineness web is 12 decitex or more (excluding 13.2 decitex or less) . If the fineness is less than 12 decitex, the stiffness of the polyester long fibers having a large fineness tends to decrease, and the stiffness of the polyester long fiber nonwoven fabric tends to decrease. It becomes large, and it is difficult to achieve the object of the present invention . The details of the method for obtaining the polyester long fibers constituting the large fineness web used in the present invention are described in detail in the above-mentioned JP-A-2013-76182.

In the present invention, since long fibers having this unique cross-sectional shape and having various irregularities are three-dimensionally entangled with each other, in a layer (large fineness web) composed of polyester long fibers, has large voids between fibers and is bulky.

Such three-dimensional entanglement of long fibers can be obtained by needle-punching a fiber web formed by accumulating long fibers. That is, a fibrous web in which long fibers are accumulated is prepared, and the fibrous web is subjected to a needle punching process to move the fiber axis direction of the accumulated long fibers also in the thickness direction, thereby entangling the long fibers. Let Since the polyester long fibers constituting the large fineness web in the present invention have a unique cross section and are excellent in rigidity, the fibers are entangled by moving the fiber axis direction of such long fibers also in the thickness direction. As a result, a layer (thick fineness web) having high rigidity in the thickness direction, little change in thickness against compression, and capable of maintaining voids between fibers is obtained.

In order to have such a high rigidity in the thickness direction, little change in thickness against compression, and to be able to maintain voids between fibers, the basis weight of the large fineness web should be 70 g/m ² or more. By setting the basis weight to 70 g/m ² or more, the relative number of constituent fibers can be secured, the fibers can be sufficiently entangled by needle punching, and the rigidity and strength can be maintained. A more preferable basis weight of the thick fineness web made of polyester long fibers is 100 g/m ² or more, and a more preferable basis weight is 200 g/m ² or more. The upper limit of the basis weight of the thick fineness web made of polyester long fibers is about 1000 g/m ² , although it may be appropriately set according to the use of the laminated long-fiber nonwoven fabric of the present invention.

The laminated continuous fiber nonwoven fabric of the present invention is obtained by laminating and integrating a fine fineness web composed of long fibers having a small single fiber fineness on at least one side of the large fineness web made of polyester long fibers having a unique cross section as described above. there is The filament fineness of the filaments constituting the fine fineness web is less than 8 decitex, preferably 2 to 6 decitex.

As described above, the large fineness web is composed of long fibers with a unique substantially Y4-shaped cross section and is three-dimensionally entangled, so there are large gaps between the fibers, and these gaps are difficult to compress in the thickness direction. It is resistant to crushing and maintains. On the other hand, in the fine fineness web, since the single fiber fineness of the constituent fibers is small, the gaps between the fibers are small, and when compressed in the thickness direction, the gaps are easily crushed and become smaller. Therefore, the laminated long-fiber nonwoven fabric of the present invention is characterized by having two different layers in terms of the size of inter-fiber voids, bulkiness, and retention of voids against compression.

The cross-sectional shape of the filaments constituting the fine fineness web is not particularly limited as long as it has a circular cross-section. A flat cross section is also preferable to reduce the gap. Further, the long fibers constituting the fine fineness web are preferably synthetic fibers, and more preferably polyester fibers.

In the laminated long-fiber nonwoven fabric of the present invention, the constituent fibers are integrated by three-dimensional entangling to maintain the form of the nonwoven fabric, and the large fineness web and the fine fineness web are integrated by the entangling. The mass ratio of the large denier web and the fine denier web may be appropriately selected according to the application of the laminated continuous fiber nonwoven fabric. From the viewpoint of obtaining a nonwoven fabric, it is preferable that the ratio of the large fineness web is large, and the ratio of large fineness web/fine fineness web is preferably 1 to 10/1.

In order to obtain a laminated nonwoven fabric by lamination and integration, a large fineness web and a fine fineness web are prepared respectively, a fine fineness web is laminated on at least one side of the large fineness web, and the laminated laminate is subjected to a needle punching treatment, Long fibers are three-dimensionally entangled and integrated. As a lamination form, even in a laminate of a large fineness web/fine fineness web in which a fine fineness web is laminated on one side of a large fineness web, a fine fineness web/thickness web in which fine fineness webs are laminated on both sides of a large fineness web It may be a fineness web/fineness web.

Needle punching may be performed from only one side of the laminate, or may be performed from both sides. The number of needle punching treatments may be appropriately designed in consideration of the basis weight of the laminate, etc., but the number of punches is preferably about 30 to 120 punches/cm ² . For the large fineness web and fine fineness web, it is also possible to use a web obtained by temporarily heat-bonding fibers together in consideration of transportability and the like. Temporary thermal bonding between fibers should be such that they can be easily unraveled by the impact of needle punching.

The laminated long-fiber nonwoven fabric of the present invention has a bulk density of 0.130 g/cc or less under a load of 100 gf/cm ² . The laminated long-fiber nonwoven fabric of the present invention is less likely to be compressed in the thickness direction and more likely to maintain the initial voids between fibers, so that the bulk density is 0.130 g/cc or less even under a load of 100 gf/cm ² . , the voids in the nonwoven fabric can be maintained, and the bulkiness is excellent.

The bulk density under a load of 100 gf/cm ² is measured by the following method. That is, the thickness is measured according to JIS L1913 6.1 Thickness (ISO method) A method. At that time, 10 sample pieces of 10 cm long × 10 cm wide were used as samples from the sample in the standard state, and a presser hood with an area of 10 cm ² was used, and a load of 100 gf/cm ² was applied to increase the thickness. Measure. The thickness (μm) of the non-woven fabric is obtained from the average value of the thicknesses measured at 10 points, and the bulk density is calculated as follows.

Bulk density (g/cc) = basis weight (g/m ² )/thickness (μm)

Furthermore, in the present invention, the bulk density, which is measured by the same method as described above, is preferably 0.160 g/cc or less when the load is 300 gf/cm ² .

The laminated long-fiber nonwoven fabric of the present invention has bulkiness, is less likely to be compressed in the thickness direction when compressed, and easily maintains its bulkiness, and can be applied to various uses. For example, since it has properties of high rigidity and excellent dust removal properties, it can be suitably used as a filter material. That is, if it is used as a filter material, it will not be easily compressed and will be excellent in handleability.

The laminated long-fiber nonwoven fabric of the present invention is buried in the soil or laid in contact with the soil in civil engineering applications , and is used as a reinforcing material for soil reinforcement, rainwater separation, etc., a separating material, and a drainage material. At this time, the drainage function is mainly performed by the layer of the thick fineness web, which maintains voids with little change in thickness against compression, while the fineness web layer has small voids, which prevents soil particles from entering the web. It plays a role of shielding against That is, if the fine fineness web is not laminated and only the large fineness web is used, soil particles and the like are likely to enter large voids in the large fineness web and block the voids. Although it becomes difficult to maintain the voids of the web, since the fine fineness web is laminated on the large fineness web, the voids of the large fineness web are covered so that foreign matter does not enter directly into the voids. It is possible to maintain the voids between the fibers of the large fineness web over a long period of time, maintain the air permeability and water permeability, etc., and function well.

The laminated long-fiber nonwoven fabric constituting the civil engineering material of the present invention is formed by laminating a large fineness web and a fine fineness web composed of polyester long fibers having a substantially Y4 shape, and the constituent fibers are three-dimensionally arranged. Since the web is integrated by entangling it, it is bulky, and since the large fineness web is composed of highly rigid polyester long fibers, it is difficult to compress in the thickness direction, and the inter-fiber gaps are maintained even when pressurized. , the bulkiness can be maintained.

The present invention will be described below based on examples, but the present invention is not limited to the examples. The present invention is a nonwoven fabric composed of a large fineness web having polyester long fibers having a specific cross-sectional shape as constituent fibers, and the constituent fibers are three-dimensionally entangled to be integrated. should be interpreted as being based on the knowledge that it has high rigidity and is difficult to compress in the thickness direction.

Example 1
(Creation of thick fineness web)
100 mol % of terephthalic acid (TPA) as a dicarboxylic acid component and 100 mol % of ethylene glycol (EG) as a diol component were copolymerized to prepare polyethylene terephthalate (relative viscosity [ηrel] 1.38, melting point 260° C.). Then, using the nozzle hole shown in FIG. Melt spinning was performed at a single hole throughput of 8.33 g/min.

A group of filaments discharged from a nozzle hole was introduced into an air sucker inlet 2 m below and pulled so that the fineness of polyester long fibers was 16.4 decitex. After the polyester long fibers discharged from the air sucker outlet were spread by a spreader, they were accumulated on a moving net conveyor to obtain a fiber web. This fiber web was embossed with a roll having a surface temperature of 190° C. (the area of each embossed protrusion tip is 0.7 mm ² , and the area ratio of the embossed protrusions to the total roll area is 15%) and a flat roll. Introduced into a clothing device, temporarily heat-bonded to improve transportability under the condition of a linear pressure of 150 N / cm between both rolls, and a basis weight of 100 g / m ² made of polyester long fibers with a cross section of approximately Y4 shape. A polyester filament nonwoven web was obtained. A web obtained by stacking two polyester long fiber nonwoven webs thus obtained was used as a large fineness web (basis weight: 200 g/m ² ).

(Preparation of fine fineness web)
100 mol % of terephthalic acid (TPA) as a dicarboxylic acid component and 100 mol % of ethylene glycol (EG) as a diol component were copolymerized to prepare polyethylene terephthalate (relative viscosity [ηrel] 1.38, melting point 260° C.). Then, using a nozzle hole with a hole diameter of 0.4 mm, melt spinning was performed at a spinning temperature of 285° C. and a single hole discharge rate of 1.67 g/min.

A group of filaments discharged from a nozzle hole was introduced into an air sucker inlet 2 m below and pulled so that the fineness of polyester long fibers was 3.3 decitex. After the polyester long fibers discharged from the air sucker outlet were spread by a spreader, they were accumulated on a moving net conveyor to obtain a fiber web. This fiber web was embossed with a roll having a surface temperature of 190° C. (the area of each embossed protrusion tip is 0.7 mm ² , and the area ratio of the embossed protrusions to the total roll area is 15%) and a flat roll. Introduced into a clothing device, temporarily heat-bonded to improve transportability under the condition of a linear pressure of 150 N / cm between ^both rolls, and made of polyester long fibers with a circular cross section. A woven web was obtained. The resulting web was used as a fine denier web.

(Preparation of laminated continuous fiber nonwoven fabric)
A laminate (basis weight: 340 g/m ² ) in which fine denier webs (each 70 g/m ² ) is laminated on both sides of a large denier web (basis weight: 200 g/m ² ) was needle-punched. In the needle punching treatment, a needle punching oil (UN-12 manufactured by DIC) is attached to 0.5% by mass with respect to the mass of the fiber, and a needle manufactured by Grotz-Beckert (654851 B271F7 JBF 15 × 18 × 40×3 C3+3 G 28017), the needle depth was 10 mm, and the number of punches was 60 punches/cm ² . The basis weight of the laminated long-fiber nonwoven fabric obtained by three-dimensionally entangling the fibers was 360 g/m ² .

Example 2
In Example 1, as the large fineness web, a lamination of three long fiber non-woven webs made of polyester long fibers with a unique irregular cross section was used as a large fineness web (basis weight: 300 g/m ² ); In this regard, as a laminate, a laminate (basis weight: 370 g/m ² ) in which a fine denier web (70 g/m ² ) is laminated on one side of a large denier web (basis weight: 300 g/m ² ) was subjected to a needle punching process. , Needle-punching treatment was performed in the same manner as in Example 1 to obtain a laminated long-fiber nonwoven fabric of Example 2. The basis weight of the obtained laminated long-fiber nonwoven fabric of Example 2 was 386 g/m ² .

Comparative example 1
In Example 1, only a fine fineness web was used without using a large fineness web, and in the needle punching process, five fine fineness webs (polyester continuous fiber nonwoven web with a basis weight of 70 g / m ² ) were stacked as a laminate. A long-fiber nonwoven fabric of Comparative Example 1 was obtained by needle-punching in the same manner as in Example 1, except that a laminated body (basis weight: 350 g/m ² ) was obtained. The basis weight of the obtained long-fiber nonwoven fabric of Comparative Example 1 was 402 g/m ² .

With respect to the obtained laminated filament nonwoven fabrics of Examples 1 and 2 and Comparative Example 1, the thickness and the thickness and bulk density under various loads were determined. Then, the thickness and the thickness under various loads were converted into the thickness per 100 g/m ² basis weight and the thickness per 100 g/m ² basis weight under the specific load was obtained.

As described above, the thickness and the thickness under various loads were measured according to JIS L1913 6.1 Thickness (ISO method) A method. 10 sample pieces, and a presser hood having an area of 10 cm ² was used for measurement. There were four loads of 20 gf/cm ² , 100 gf/cm ² and 300 gf/cm ² . The thickness (μm) of the nonwoven fabric was determined from the average value of the thicknesses measured at 10 points, and the bulk density was calculated according to the following formula.

Bulk density (g/cc) = basis weight (g/m ² )/thickness (μm)

In addition, the air permeability of the obtained laminated long-fiber nonwoven fabrics of Examples 1 and 2 and Comparative Example 1 was measured. Air permeability (cc/cm ² ) was measured using a Frazier type air permeability tester (DAIEI KAGAKUSEIKI SEISAKUSHO LTD. TEXTILE AIR PERMEABILITY TESTER) in accordance with JIS L 1096 "General Textile Test Method". , and the tilt-type barometer was fixed at 12.7 mm to measure air permeability. Then, the air permeability value obtained was converted to per 100 g/m ² of basis weight, and the air permeability per 100 g/m ² of basis weight was obtained.

Table 1 shows the results.

本発明の実施例と、比較例とを対比すれば明らかなとおり、実施例に係る積層長繊維不織布は、圧縮した際の厚みの変化が少なく、嵩密度も高いので繊維間空隙を維持していることが分かる。また、実施例に係る積層長繊維不織布の通気度も、比較例と対して、高いものであった。

As is clear from comparing the examples of the present invention with the comparative examples, the laminated filament nonwoven fabrics according to the examples show little change in thickness when compressed and have a high bulk density, so that inter-fiber voids can be maintained. I know there is. Moreover, the air permeability of the laminated long-fiber nonwoven fabric according to the example was also higher than that of the comparative example.

FIG. 2 is a view showing one substantially Y shape of the substantially Y4 shape, which is the cross-sectional shape of polyester long fibers used in the present invention. FIG. 2 is a diagram showing a substantially Y4 shape, which is the cross-sectional shape of polyester long fibers in the present invention. It is the figure which showed the nozzle hole of Y4 type used for this invention.

1 Lower end of one substantially Y shape of substantially Y4 shape which is the cross-sectional shape of the polyester filament 2 Concave portion formed in substantially Y4 shape 3 Convex portion formed in substantially Y4 shape 4 Small concave portion formed in substantially Y4 shape 5 Substantially +-shaped portion in substantially Y4 shape 6 Substantially V-shaped portion in substantially Y4 shape

Claims (3)

A civil engineering material to be buried in the soil or laid in contact with the soil, the civil engineering material being a ground reinforcement material, a rainwater separation material, or a drainage material,
The civil engineering material is A thick fineness web whose constituent fibers are long fibers having a large single fiber fineness and a fine fineness web whose constituent fibers are long fibers whose single fiber fineness is smaller than that of the coarse fineness web are laminated.needle punchLaminated long fiber nonwoven fabriccomposed by,
The large fineness web and the fine fineness web are formed by three-dimensionally entangling the constituent fibers and stacking them together.
The thick fineness web has polyester long fibers as constituent fibers, and the cross-sectional shape of the polyester long fibers is connected vertically and horizontally at the lower end of a substantially Y shape.

shape (hereinafter referred to as “substantially Y4 shape”), and the single fiber fineness is12decitex or better(However, 13.2 decitex or less is excluded.),
The fine fineness web has a single fiber fineness of less than 8 decitex,
The basis weight of the laminated long fiber nonwoven fabric is 100 g/m²100 gf/cm or more²Characterized by having a bulk density under load of 0.130 g/cc or lesscivil engineering materials. 2. The civil engineering material according to claim 1, wherein the polyester filaments constituting the thick fineness web are polyethylene terephthalate filaments. The single fiber fineness is 12 decitex or more (excluding 13.2 decitex or less) , and the cross-sectional shape of the long fibers is approximately Y-shaped and connected vertically and horizontally at the lower end.

Polyester filaments having a shape (hereinafter referred to as "approximately Y4 shape") having a single fiber fineness of less than 8 decitex are deposited on one side of a large fineness web formed by stacking the polyester filaments. Laminating the fine fineness web formed by
2. The method of manufacturing a civil engineering material according to claim 1, wherein the laminate is needle-punched to three-dimensionally entangle the filaments constituting the laminate to integrate them.

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