JP2003301346A - Mesh sheet for civil engineering - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mesh sheet for civil engineering, requiring no post processing for applying a vinyl chloride resin or the like, having excellent lightweight and workability, functions required for the mesh sheet for civil engineering and excellent weathering resistance. <P>SOLUTION: This mesh sheet is woven/knitted by using a sheath-core conjugate fiber yarn having the core comprising a polyester polymer and the sheath comprising another polyester polymer having a lower melting point than that of the core polyester polymer and has ≥70% strength retention after 1, 000 h irradiation by a sunshine carbon arc weatherometer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight mesh sheet for civil engineering, which is excellent in weather resistance.

[0002]

2. Description of the Related Art Conventionally, geotextiles used for civil engineering work are used in various fields including ground improvement, ground strengthening, embankment strengthening and the like. The mesh sheet shape has been drawing attention because of its light weight and strong pull-out strength due to its engagement with stones. The necessary properties as a civil engineering mesh sheet include tensile strength, tear strength, toughness, abrasion resistance, intersection strength, etc., but it is also required to have excellent weather resistance because it is used outdoors.

As a civil engineering mesh sheet, a cloth covered with vinyl chloride resin is mainly used. For example, there is one in which a cloth woven of synthetic fiber yarn is processed by a method such as dipping or coating using a vinyl chloride resin. Since the mesh sheet coated with vinyl chloride resin has excellent workability,
Various processing methods can be adopted, and the flexibility can be adjusted as desired. However, those coated with a vinyl chloride resin are heavy and inferior in workability, and further weight reduction is desired.

On the other hand, a mesh sheet composed of multifilament yarns not coated with vinyl chloride resin is light in weight, but has a low density and its intersections are not fixed, so that misalignment is likely to occur and abrasion resistance is high. It is also inferior in terms of workability as a mesh sheet at the work site. Further, in JP-A-6-299470, a core-sheath composite in which a sheath component is composed of at least one selected from polyolefin resins, polyacrylic resins, melamine resins, urea resins, fluororesins and polyamide resins A mesh sheet woven and knitted with yarns made of fibers, in which the yarns are covered with a synthetic resin, has been proposed. However, in this case, under the special condition of high-temperature alkaline water resistance, although the desired durability can be obtained by the coating resin, the intersection strength required by the civil engineering mesh sheet is not sufficient, and the coating resin is However, for the purpose of weakening against abrasion and further reducing the weight, it is disadvantageous to coat the resin as the post-processing because the weight becomes heavier.

[0005]

DISCLOSURE OF THE INVENTION The present invention has been made in view of such a situation as described above, and is lightweight and excellent in workability without adding a vinyl chloride resin or the like by post-processing, and is a mesh for civil engineering. An object of the present invention is to provide a mesh sheet for civil engineering, which has a sheet with necessary functions and is also excellent in weather resistance.

[0006]

MEANS FOR SOLVING THE PROBLEMS The mesh sheet for civil engineering of the present invention is to solve the above-mentioned problems and is lower than the polyester polymer in the core portion and the polyester polymer in the sheath portion. Characterized by being knitted and woven using a core-sheath composite fiber yarn in which a polyester polymer having a melting point is arranged, and having a tenacity retention of 70% or more after irradiation with a sunshine carbon arc weather meter for 1000 hours. The main purpose is a mesh sheet for civil engineering.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The civil engineering mesh sheet of the present invention comprises a core-sheath composite fiber yarn in which a polyester-based polymer is arranged in the core portion and a polyester-based polymer having a melting point lower than that of the polyester-based polymer in the core portion is arranged in the sheath portion. It is a mesh sheet that has been knitted and woven using it. The polymer of the core portion of the core-sheath composite fiber yarn used in the present invention is a polyester polymer mainly composed of polyethylene terephthalate or ethylene terephthalate from the viewpoint of tensile strength, dimensional stability during use, and productivity. Is preferred. This polyester-based polymer contains polyethylene terephthalate as a main component, and has characteristics of polyethylene terephthalate, particularly a melting point of 240 ° C.
It may be a polyester obtained by copolymerizing a third component, an additive and the like to the extent that the above is maintained. The additives specifically include pigments, flame retardants, ultraviolet absorbers, antistatic agents, heat-resistant agents, and the like.

The sheath of the core-sheath composite fiber yarn used in the present invention must be provided with a polyester polymer having a lower melting point than the polyester polymer of the core. Since the polymer of the sheath and the polymer of the core are required to have adhesiveness to each other, a polyester polymer is also used for the sheath.

In order to make the polyester polymer used for the sheath portion have a melting point lower than that of the core portion, it is preferable to use the polyester copolymer for the sheath portion. As the polyester-based copolymer used for such a sheath,
One or more dibasic acids or their derivatives,
Examples thereof include polyester-based copolymers obtained by reacting one or more glycol-based compounds. Examples of the dibasic acid include aromatic dibasic acids such as terephthalic acid, isophthalic acid, phthalic acid, p-oxybenzoic acid, 5-sodium sulfoisophthalic acid, and naphthalenedicarboxylic acid.
Examples thereof include aliphatic dibasic acids such as oxalic acid, adipic acid, sebacic acid, azelaic acid and dodecanedicarboxylic acid, and alicyclic dibasic acids such as 1,2-cyclobutanedicarboxylic acid. On the other hand, examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol,
Examples thereof include propanediol, butanediol, pentanediol, hexanediol, neopentanediol, p-xylene glycol, and polyalkylene glycols such as polyethylene glycol and polytetramethylene glycol. This polymer has good thermal stability, and the raw materials can be supplied relatively inexpensively, which is industrially advantageous.

Further, as the polyester polymer of the sheath portion, a copolyester having a melting point (crystal melting point) at which the aromatic polyester and the aliphatic lactone are copolymerized is 100 ° C. or more is more preferable. In this case, the aromatic polyester is a polymer of ethylene terephthalate units and / or butylene terephthalate units, or in addition to these, isophthalic acid, 2,6-naphthalenedicarboxylic acid,
Adipic acid, sebacic acid, ethylene glycol, 1,6
-Hexanediol and the like are copolymerized, and the total of the components to be copolymerized is preferably about 20 mol% or less based on the number of moles of the constituent components of the polyester. As the aliphatic lactone, lactones having 4 to 11 carbon atoms may be used alone or in combination of two or more,
Particularly good lactones include ε-caprolactone and δ-
Valerolactone and the like can be mentioned.

The melting point of the polyester polymer of the sheath is 10
0 ° C or higher is preferable, and 130 ° C or higher is particularly preferable. If the melting point is less than 100 ° C., it tends to deform when used in a high temperature atmosphere, which is not preferable. Further, the polyester polymer of the sheath portion needs to have a lower melting point than the polyester polymer of the core portion, and is 20 ° C. or higher than the melting point or decomposition point of the polyester polymer which is the main component of the core portion. Having a low melting point is preferable for processing.

Since the mesh sheet for civil engineering of the present invention is used outdoors for a long period of time, it is required to have excellent weather resistance, and the index of this point is 1000 by a sunshine carbon arc weather meter. It is necessary that the tenacity retention rate after irradiation after a lapse of time is 70% or more. If it is less than that, durability for a long period of time is deteriorated, and the object of the present invention cannot be achieved.

From the viewpoint of providing such excellent weather resistance, the sheath portion of the core-sheath type composite fiber used in the mesh sheet for civil engineering of the present invention includes a terephthalic acid component, an aliphatic lactone component, an ethylene glycol component and A copolyester composed of a 1,4-butanediol component is preferred.

It is also preferable that the core of the core-sheath type composite fiber contains a weathering agent in order to improve weatherability. The kind, color and concentration of such a weatherproofing agent can be selected according to the application if the spinnability is not impaired so much and the weatherability is improved, but among them, inexpensive and versatile carbon is preferable. Examples of the method of incorporating a weathering agent into the core include polyester, preferably PET (polyethylene terephthalate) kneaded with a weathering agent at a concentration of about 20 to 40% by mass to form a masterbatch, and polyester used as a core component. It is possible to employ a method in which PET and PET are mixed and kneaded so as to have an arbitrary weatherproofing agent concentration by using a metering mixer or the like. Further, the concentration of the weatherproofing agent in the core component is about 0.2 to 2.0% by mass, and particularly 0.1.
5 to 1.0% by mass is preferable, and if the concentration is lower than this range, the weather resistance tends to be poor, and if the concentration is high, the yarn formability tends to deteriorate and the strength tends to deteriorate, such being undesirable.

The mass ratio of the core portion to the sheath portion of the core-sheath composite fiber yarn used in the present invention is preferably 50/50 to 90/10. When the mass ratio of the core portion is less than 50%, the ratio of the sheath portion increases and the adhesive strength at the intersections of the yarns becomes stronger, but the tensile strength of the mesh sheet itself becomes small, which is not preferable. On the other hand, when the mass ratio of the core portion exceeds 90%, the ratio of the sheath portion is too low, so that sufficient intersection strength cannot be obtained.

The core-sheath composite fiber yarn used in the present invention has a strength of 3.53 cN / in order to obtain basic physical properties such as tensile strength, tear strength, toughness, wear resistance, and adhesive strength at intersections of the mesh sheet. dtex or more, elastic modulus 60 cN / d
It is preferably tex or more. Further, in the present invention, since it is premised that the resin for the purpose of protecting the fiber and obtaining the intersection strength is not applied in the post-processing, the polyester polymer in the sheath is heat-treated to form the fiber yarn. In order to sufficiently cover and maintain the strength, it is preferable that the single filament fineness is 3.3 to 17 dtex and the number of filaments is 40 or more. Single filament fineness is 3.3d
When it is less than tex, weavability is difficult and strength is insufficient, which is not preferable. The single filament fineness is 17 dte
If it exceeds x, the adhesion between single fibers becomes insufficient,
In addition, there is a problem in wear resistance, which is not preferable. Further, if the number of filaments is less than 40, problems occur in strength, adhesion between single fibers, etc., which is not preferable.

Regarding the mesh sheet for civil engineering work, various standards such as required strength are required. Therefore, in manufacturing, a fiber yarn having a structure suitable for required strength can be used.

The civil engineering mesh sheet is required to be free from misalignment, to be free from misalignment even during work, and to be stable even when handled hard. As an index of the difficulty of misalignment, the pin hooking strength measured according to JIS-L-1096 is suitable, and the pin hooking strength is preferably 500 N or more.
The core-sheath composite polyester fiber filament yarn is preferably 550 to 1100 decitex in that the intersection of the warp and the weft is fixed and the pin hooking strength is 500 N or more.

The civil engineering mesh sheet of the present invention is
Since it is used outdoors under severe conditions, it preferably has excellent wear resistance, and the strength retention after the belt wear test, which is an index for this point, is preferably 80% or more. . If it is less than that, it is not preferable because it is inferior in wear resistance.

In the civil engineering mesh sheet of the present invention, after a coarse cloth is made using the above-mentioned core-sheath composite fiber yarn, the melting point of the polyester-based polymer of the sheath or more and the polyester-based polymer of the core are obtained. It can be obtained by heat-treating at a temperature below the melting point or decomposition point of to soften or melt the resin in the sheath and fuse the intersections of the yarns. Examples of the coarse fabric include a coarse woven fabric, a warp-inserted Russell knitted fabric, and the like. It is rational to heat the cloth by providing a heating zone before winding it on the cloth making machine, and the cost can be reduced. It is possible to prevent misalignment due to the fusion of the yarns, to make resin coating unnecessary, and to save labor in the processing steps. Of course, there is no problem even if heat treatment is performed in a separate step after winding.

As described above, the warp yarns and the weft yarns are fused by the resin of the sheath, and as a result, misalignment hardly occurs, workability is excellent, and tensile strength, tear strength, and pin strength are high. The mesh sheet for civil engineering has excellent physical properties such as hooking strength, toughness, and weather resistance. Further, the civil engineering mesh sheet of the present invention, at the time of construction, even when the mesh sheet is used as a large-area sheet to be joined, thermal bonding sewing is possible, and it is possible to increase the sewing strength in combination with sewing sewing. It will be possible.

[0022]

EXAMPLES Next, the present invention will be described in detail with reference to examples. The evaluation of the performance in the examples was performed by the following method. (1) Unit weight (unit: g / m ² ) It was measured according to JIS-L-1096. (2) Tensile strength (unit: kN / m), cutting elongation (unit:
%) Measured in 5 cm width according to JIS-L-1096, 1 m
Converted to width. (3) Belt wear (strength retention rate) Using a belt wear tester conforming to JIS-D-4606,
A 5 cm wide sample was subjected to a belt wear test with a load of 5 kg, a wear metal hexagonal rod, a repetition rate of 30 times / min, and a maximum number of repetitions of 10,000 times, and the tensile strength after the test was measured to make it stronger than the initial one. The retention rate was calculated. However, 100
The measurement was not performed for those cut up to 00 times. (4) Pin hooking strength (unit: N) It was measured according to JIS-L-1096. (5) Weather resistance (strength retention) Measured according to JIS-A-1415. Each sample was tested with a sunshine carbon arc lamp type weather resistance tester for 10
The strength of the sample was measured after irradiation for 00 hours, and the strength retention was determined from the following formula from the strength measured for the sample before irradiation. Tester: Sunshine carbon arc weather meter Type of light source: WS type black panel temperature: 63 ± 3 ° C Number of samples to be measured: 5 each Power retention rate calculation formula: Power retention rate (%) = (Power after irradiation / irradiation Previous strong) ×
100

Example 1 Polyethylene terephthalate (melting point 260 ° C.) was used as the core of the core-sheath composite fiber. The sheath has a molar ratio of terephthalic acid component to ethylene glycol component of 1:
Copolymerization obtained by adding ε-caprolactone to the PET oligomer of 1.13 at a ratio of 15 mol% to all acid components and 1,4-butanediol at a ratio of 50 mol% to all diol components. Polyester (melting point 160 ° C.) was used. A multifilament (1100 dtex / 96 filament) composed of a core-sheath composite fiber in which the above polyester-based polymer is arranged in a core part and a sheath part and the mass ratio of the core-sheath is 50/50 is used by a conventional composite spinning machine. I got it. Using a yarn obtained by plying 4 multifilaments with S twist 80 T / M as warp and weft, the warp density is 7.0 /
2.54 cm, weft density of 9.5 yarns / 2.54 cm, weaving with a mock weave fabric to obtain a woven fabric having a texture of 7.8 mm in both warp and weft. This fabric was heat-treated at 170 ° C. for 2 minutes to obtain a civil engineering mesh sheet.

Example 2 Carbon was added to the core in the same manner as in Example 1 except that carbon was added at a ratio of 0.63 parts by mass of carbon to 100 parts by mass of the polyester polymer of the core. A mesh sheet for civil engineering of the present invention was obtained.

Comparative Example 1 A polyester fiber 1100 dtex 96 filament made of polyethylene terephthalate was used in Example 1
Weaving was performed in the same manner as described above, a vinyl chloride resin having the following vinyl chloride paste composition was applied, and heat treatment was performed at 100 ° C. × 2 minutes for drying and 180 ° C. × 30 seconds for curing to obtain a comparative civil engineering mesh sheet. [Vinyl chloride paste composition] -Zeon 121 50 parts (Nippon Zeon Co., Ltd. vinyl chloride resin paste) -Dioctyl phthalate 15 parts (Mitsubishi Sunmont Co., plasticizer) -Diisonoyl phthalate 15 parts (Mitsubishi Sunmont Co., Ltd.) , Plasticizer) -Ade Force-O-130P 3 parts (Adeka Argus Chemical Co., Ltd., epoxy plasticizer) -KV-62B-4 3 parts (Kyodo Chemical Co., Ltd., barium-zinc powder stabilizer)・ 7 parts antimony trioxide (flameproofing agent) ・ 7 parts calcium carbonate (filler)

The characteristics of the civil engineering mesh sheets obtained in the above Examples and Comparative Examples are shown in Table 1 below.

[0027]

[Table 1]

As is apparent from Table 1, the civil engineering mesh sheets of the present invention obtained in Examples 1 and 2 have a higher pin hooking strength than Comparative Example 1 which is a conventional vinyl chloride resin processed product. It was a mesh sheet for civil engineering, which was extremely excellent in abrasion resistance and weather resistance. On the other hand, Comparative Example 1 was inferior in terms of weather resistance.

[0029]

EFFECTS OF THE INVENTION According to the present invention, it is possible to obtain a civil engineering mesh sheet which is excellent in basic performance as a civil engineering mesh sheet and is also excellent in weather resistance without resin coating.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) E02D 3/00 102 E02D 3/00 102 17/18 17/18 A // D01F 8/14 D01F 8/14 BF term (reference) 2D043 CA20 DD04 2D044 CA01 4L041 AA07 BA02 BA05 BA21 BA24 BC04 BD03 CA06 CA13 CB16 DD05 DD21 4L048 AA21 AA28 AA44 AA56 AC18 BA06 CA11 CA15 DA30

Claims (3)

[Claims] 1. A core-sheath composite fiber yarn in which a polyester polymer is arranged in a core portion and a polyester polymer having a melting point lower than that of a polyester polymer in a core portion is arranged in a sheath portion, and is knitted and woven. A mesh sheet for civil engineering, which has a high strength retention of 70% or more after irradiation with a sunshine carbon arc weather meter for 1000 hours. 2. The sheath part of the core-sheath composite fiber is a polyester copolymer comprising terephthalic acid, an aliphatic lactone, ethylene glycol and a 4,4-butanediol component. A mesh sheet for civil engineering. 3. The mesh sheet for civil engineering according to claim 1 or 2, wherein the core portion of the core-sheath composite fiber contains a weathering agent.