JP2009228377A - Civil engineering geogrid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a civil engineering geogrid containing a biomass-derived polymer at 25 wt.% at least to meet dynamic material property while reducing environmental load and economically producible. <P>SOLUTION: The civil engineering geogrid is formed by applying resin treatment to a foundation cloth composed of fiber containing the biomass-derived polymer with a strength of 5 cN/dtex or more and an elongation of 25% or less, having a cover factor of 350 to 900 and a quadrangular mesh form with one side of mesh size being 3-50 mm. The content ratio of the biomass-derived polymer to the geogrid is 25-50 mass%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a geogrid for civil engineering that is used by being laid in the soil for civil engineering work such as ground improvement and ground reinforcement.

  Most of the conventional synthetic fibers are made from limited fossil fuel resources such as oil, but in recent years, the fossil fuel resources are not only concerned with the remaining reserves but also carbon dioxide generated during incineration disposal. It has become a big social problem as an inducer of global warming. Therefore, there is an urgent need to search and develop new resources that can solve the above-mentioned problems. Among these, biomass-derived substances are attracting attention as resources that do not produce excess carbon dioxide even after disposal. This is because, even if the materials produced from biomass-derived substances are combusted, the carbon dioxide generated at that time was originally in the atmosphere, and in the time scale of human industrial activities, This is based on the idea that the macro balance of carbon dioxide does not increase. This is called carbon neutral and tends to be regarded as important.

  For example, biomass-derived plastic products have features such as less environmental impact than petroleum-based plastic products and do not disturb the balance of carbon dioxide gas, preventing global warming and saving fossil fuel resources. The recognition that it contributes to the conservation of the natural environment is becoming socially established. On the other hand, in order to promote the spread of plastic products derived from biomass, the Japan Bioplastics Association, a voluntary private organization, has established the “Biomass Plastic Identification and Labeling System” as a system for distinguishing it from existing petroleum-based plastic products. It is advocated, and the certification standard is that it contains 25.0 mass% or more of the biomass-derived polymer component.

  Here, focusing on the geogrid for civil engineering, a geogrid for civil engineering is disclosed in which synthetic fibers are woven and this base fabric is resin processed (see, for example, Patent Documents 1 and 2). However, all of these disclosed technologies use petroleum-derived polymers, and there is no description using a biomass-derived polymer, and there is no description suggesting the necessity thereof.

  Therefore, no technology for producing geogrids for civil engineering using environmentally friendly biomass has been found. Nevertheless, under the present circumstances, the biomass-derived polymer has a problem that it is not cheap because the production amount is smaller than that of the general-purpose resin.

JP 2004-036006 A JP 2001-140259 A

  The present invention has been made in view of such a situation, and is friendly to the environment such as reducing the amount of carbon dioxide generated by containing at least 25 wt% or more of a biomass-derived polymer, and used in combination with a petroleum-based polymer. It aims to provide a geogrid for civil engineering that can be produced economically.

  As a result of intensive studies to solve such problems, the present inventors have made a biomass-derived polymer 25 to 50 mass with respect to the total mass of the geogrid for civil engineering. It has been found that it is possible to obtain a geogrid for civil engineering that is environmentally friendly and has physical properties that are inferior to each other by containing it in the range of%.

That is, the gist of the present invention is as follows.
(A). A geogrid formed by subjecting a base fabric to resin processing, the base fabric comprising fibers having a strength of 5 cN / dtex or more and an elongation of 25% or less containing a biomass-derived polymer, and a cover of 200 to 900 It has a factor (CF: Formula (1) below) and a quadrilateral mesh-like shape in which one side of the mesh is 3 to 50 mm, and the content ratio of the biomass-derived polymer to the geogrid is 25 to 25 A geogrid for civil engineering, which is 50% by mass.
(B). The geogrid for civil engineering according to (a), wherein the base fabric is constituted by a core-sheath type composite fiber in which a biomass-derived polymer is disposed in a core part and a petroleum-based polymer is disposed in a sheath part.
(C). The civil engineering according to (a) and (b), wherein the fiber comprising the biomass-derived polymer is a composite fiber having a core-sheath structure, wherein the core part is made of polylactic acid and the sheath part is made of polyethylene terephthalate. Geogrid for.
CF = Td · (Ts / pt) ^1/2 + Yd · (Ys / py) ^1/2 (1)
Td: Vertical weave density (main / 2.54cm)
Yd: Horizontal weave density (main / 2.54cm)
Ts: Warp yarn fineness (decitex)
Ys: Weft yarn fineness (decitex)
pt: specific gravity of the warp yarn material (g / ^cm 3)
py: specific gravity of the weft material (g / cm ³ )

  Since the geogrid for civil engineering of the present invention contains 25 to 50% by mass of the biomass-derived polymer, it is also in the atmosphere for incineration disposal compared to the conventional geogrid for civil engineering in which all components are composed of petroleum-based polymers. There is little increase in carbon dioxide, and it has the effect of reducing global warming.

  In addition, the geogrid for civil engineering of the present invention contains fibers having a biomass-derived polymer rich in aliphatic components as a constituent component in an amount of 25 to 50% by mass, but has a strength of 5 cN / dtex or more and elongation of 25% or less. And has a cover factor in a suitable area and maintains a specific mesh form, so it maintains excellent performance in terms of mechanical properties and workability required for geogrids for civil engineering. Yes. In addition, these forms are maintained well against the force of the shearing method in the vertical direction in the soil or on the inclined surface because the base fabric made of the fibers and the processed resin in the present invention are closely joined. As a result, the above-mentioned mechanical characteristics and workability can be stably maintained.

  The geogrid for civil engineering of the present invention can be suitably used as a geogrid for civil engineering that is buried in the soil and used for civil works such as ground improvement and ground reinforcement.

Hereinafter, the present invention will be described in detail.
The geogrid for civil engineering of the present invention has a form formed by subjecting a base fabric composed of fibers containing a polymer derived from biomass to resin processing. The base fabric and the resin applied to the base fabric It consists of a processing part.

  The fiber composed of a polymer derived from biomass constituting the base fabric in the present invention (hereinafter sometimes referred to as fiber in the present invention) is used as warp and weft forming the base fabric, and has a strength. The filament needs to be 5 cN / dtex or more and an elongation of 25% or less, and preferably has a strength of 7 to 15 cN / dtex and an elongation of 10 to 22%. Here, if the strength of the fiber is less than 5 cN / dtex, the fiber may be unable to withstand the stress applied during and after the construction. Moreover, when the elongation of the fibers exceeds 25%, the civil geogrid may be stretched and collapsed when slipping of the debris after construction occurs.

  That is, the fiber according to the present invention has a property that the strength is 5 cN / dtex or more and the elongation is 25% or less, so that it is a geogrid having a polymer content ratio derived from biomass as described later, but derived from petroleum. Mechanical properties comparable to those of conventional geogrids made only of polymers can be maintained.

  The biomass-derived polymer in the present invention is not particularly limited as long as it can be melt-spun. Specifically, polymers obtained by chemically polymerizing monomers derived from biomass such as PLA (polylactic acid), PTT (polytrimethylene terephthalate), and PBS (polybutylene succinate), and PHA (polyhydroxybutyrate) such as polyhydroxybutyric acid. And microbial production systems such as alkanoates). Polylactic acid that is stable in heat resistance and relatively mass-produced is preferable.

  Examples of polylactic acid include poly D-lactic acid, poly L-lactic acid, poly D-lactic acid which is a copolymer of poly D-lactic acid and poly L-lactic acid, and a mixture of poly D-lactic acid and poly L-lactic acid (stereo Complex), a copolymer of poly D-lactic acid and hydroxycarboxylic acid, a copolymer of poly L-lactic acid and hydroxycarboxylic acid, poly D-lactic acid or poly L-lactic acid, aliphatic dicarboxylic acid and aliphatic diol Or a blend of these.

  In addition, when polylactic acid is used, it is one in which D-lactic acid and L-lactic acid are used alone or in combination as described above. Among them, the melting point is 120 ° C. or higher, and the heat of fusion is 10 J. / G or more is preferable. For example, poly L-lactic acid and poly D-lactic acid, which are homopolymers of polylactic acid, have a melting point of about 180 ° C., but in the case of a copolymer of D-lactic acid and L-lactic acid, If it is about 10 mol%, the melting point will be about 130 ° C. Furthermore, when any component is 18 mol% or more, the melting point is less than 120 ° C., the heat of fusion is less than 10 J / g, and almost completely amorphous properties are obtained. When such an amorphous polymer is used, it becomes difficult to heat-stretch particularly during the production process, and it becomes difficult to obtain high-strength fibers, and even if fibers are obtained, heat resistance, abrasion resistance Since it becomes inferior in property, it is not preferable. Therefore, as polylactic acid, L / D or D / which is the content ratio (molar ratio) of L-lactic acid or D-lactic acid represented by the content ratio of L-lactic acid or D-lactic acid when polymerizing using lactide as a raw material. L is preferably 82/18 or more, more preferably 90/10 or more, and even more preferably 95/5 or more.

  Further, when the polylactic acid used is a mixture (stereocomplex) of poly D-lactic acid and poly L-lactic acid as described above, the melting point is as high as 200 to 230 ° C. and is not easily affected by frictional heat or the like. Therefore, it is particularly preferable. Further, when the polylactic acid used is a copolymer of polylactic acid and hydroxycarboxylic acid, specific examples of hydroxycarboxylic acid include glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxypentanoic acid hydroxyheptane Examples thereof include acid, hydroxyoctanoic acid, etc. Among them, it is preferable from the viewpoint of cost to use hydroxycaproic acid or glycolic acid. In the case of a copolymer of polylactic acid, aliphatic dicarboxylic acid and aliphatic diol, the aliphatic dicarboxylic acid and aliphatic diol include sebacic acid, adipic acid, dodecanedioic acid, trimethylene glycol, 1,4-butane. Diol, 1,6-hexanediol, etc. are mentioned. Moreover, when copolymerizing another component with such polylactic acid, it is preferable to make polylactic acid 80 mol% or more. When the polylactic acid is less than 80 mol%, the crystallinity of the copolymerized polylactic acid tends to be low, and the melting point is less than 120 ° C. and the heat of fusion is less than 10 J / g.

  The molecular weight of polylactic acid is 1 to 100 (g / 10 min) as measured by a temperature of 210 ° C. and a load of 2160 g according to ASTM D-1238 method used as an index of molecular weight. More preferably, it is 5-50 (g / 10min). By setting the melt flow rate within this range, the strength, wet heat decomposability and wear resistance are further improved.

 For the purpose of enhancing the durability of polylactic acid, a terminal blocking agent such as an aliphatic alcohol, a carbodiimide compound, an oxazoline compound, an oxazine compound, or an epoxy compound may be added to polylactic acid. Furthermore, as long as it does not impair the object of the present invention, it is necessary to add a heat stabilizer, crystal nucleating agent, matting agent, pigment, light-proofing agent, weathering agent, lubricant, antioxidant, antibacterial agent in polylactic acid. Perfumes, plasticizers, dyes, surfactants, flame retardants, surface modifiers, various inorganic and / or organic electrolytes, and other similar additives may be added.

  The polymer other than the biomass-derived polymer used in the geogrid for civil engineering of the present invention is not particularly limited, but when used as a base fabric, it may be a petroleum-based polymer that can be melt-spun. preferable. Specifically, polyesters typified by polyalkylene terephthalates such as polyethylene terephthalate (PET), polybutylene terephthalate, polytrimethylene terephthalate: nylon 6, nylon 66, nylon 46, nylon 11 and nylon 12 Polyamide: Polyolefins typified by polypropylene and polyethylene: Polychlorinated polymers typified by polyvinyl chloride and polyvinylidene chloride: Polytetrafluoroethylene and its copolymers, fluorinated fibers typified by polyvinylidene fluoride, vinylon Resin etc. are mentioned. Polyester and polyamide polymer, which are low cost, are preferable. More preferably, since the biomass polymer has a large amount of an aliphatic polyester polymer, a polyester polymer is preferable in terms of compatibility. Particularly preferred is polyethylene terephthalate in view of cost and handleability.

  In view of viscosity, thermal characteristics, and compatibility, the polyester polymer may be copolymerized with other monomer components. For example, examples of the acid component include aromatic dicarboxylic acids such as isophthalic acid and 5-sulfoisophthalic acid: aliphatic dicarboxylic acids such as adipic acid, succinic acid, suberic acid, sebacic acid, and dodecanedioic acid, and alcohol components. Examples thereof include aliphatic diols such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Also, a hydroxycarboxylic acid such as glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxypentanoic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, or an aliphatic lactone such as ε-caprolactone may be copolymerized. .

  In addition, the base fabric in the present invention is not particularly limited, and can be handled with a woven fabric or a knitted fabric. In the field where strength is required, a woven fabric in which the strength of the raw yarn is easily reflected is preferable, and when a coarse mesh such as a grid is required, weft insertion Russell knitting can be used. The woven fabric is not particularly limited, and various forms can be taken depending on the use. The texture of the woven fabric can be selected as appropriate depending on the raw yarn and the conditions of use.

However, as the base fabric in the present invention, particularly in the case of a woven fabric, the cover factor (CF) needs to be 200 or more and less than 900. Formula (1) shows the formula for calculating the cover factor.
CF = Td · (Ts / pt) ^1/2 + Yd · (Ys / py) ^1/2 (1)
However, Td: Vertical weave density (main / 2.54cm)
Yd: Horizontal weave density (main / 2.54cm)
Ts: Warp yarn fineness (dtex)
Ys: Weft yarn fineness (dtex)
pt: specific gravity of the warp yarn material (g / ^cm 3)
py: specific gravity of the weft material (g / cm ³ )
Here, when the CF is less than 200, the mesh of the obtained base fabric and geogrid becomes too large, so that the strength required for reinforcement cannot be obtained. Moreover, the anti-slip effect of soil cannot be expected. On the other hand, when the CF is 900 or more, the mesh becomes small, so that it is not possible to expect a soil bridging or meshing effect through the reinforcing material.

  Furthermore, it is necessary for the base fabric in the present invention to have a quadrilateral mesh shape in which one side of the mesh is 3 to 50 mm, preferably 5 to 30 mm. Here, when one side of the mesh is less than 3 mm, the bridge or meshing effect of the upper and lower earth and stones via the mesh is hindered, the pulling resistance is reduced, and the reinforcing effect is diminished. On the other hand, when one side of the mesh exceeds 50 mm, the grid density in the earth and stones decreases, and the soil slip prevention effect decreases.

  In the geogrid for civil engineering of the present invention, the biomass-derived polymer is used as a fiber as a fiber, but the method and form thereof are not particularly limited. Specifically, a method of using a fiber made of a petroleum-derived polymer and a fiber made of a biomass-derived polymer in a twisted manner, a method of weaving separately in the weft direction of the fabric, and a petroleum-based system at predetermined intervals A method of setting and using fibers made of a polymer derived from and a fiber made of a polymer derived from a biomass, a method of covering and using a fiber made of a polymer derived from a biomass and a fiber made of a petroleum derived polymer, and a petroleum derived polymer Examples thereof include a composite fiber using a biomass-derived polymer and a method using a combination thereof. Among these, the method of using as a composite fiber is preferable because the mechanical property and the thermal property of the fiber made of petroleum-based polymer and the fiber made of biomass-derived polymer are different.

  Further, as the composite fiber, fibers obtained by a known technique such as a modified cross-section type composite fiber, a side-by-side type composite fiber, and a core-sheath type composite fiber can be appropriately selected. In use, a core-sheath type composite fiber is preferable. Furthermore, the core-sheath type composite fiber is a concentric core-sheath composite fiber in which the core part and the sheath part are substantially concentrically arranged, so that unevenness in mechanical and thermal properties is unlikely to occur. ,preferable. By setting it as such a structure, there can exist an effect which distributes a general purpose polymer uniformly to a sheath part. When it exists on an eccentricity, a thin part will arise in the general-purpose polymer layer of a sheath part, and when the general-purpose polymer layer is thin and contraction occurs during resin processing, it will be eccentric and cause misalignment and wrinkles. A composite fiber having such a core-sheath structure can be produced by a known technique.

  Furthermore, the core-sheath composite fiber preferably has a structure in which a biomass-derived polymer is disposed in the core and a polymer other than biomass is disposed in the sheath. Furthermore, it is more preferable that the core part is polylactic acid which is a biomass-derived polymer, and the sheath part is ethylene terephthalate which is a petroleum-based polymer.

  Moreover, as a core-sheath ratio (mass ratio) in the said core-sheath composite fiber, it is preferable that it is core part / sheath part = 50 / 50-90 / 10. When the ratio of the core part using the biomass-derived polymer is less than 50, the amount of the biomass-derived polymer used is small, so that it is not suitable for the purpose of the present invention. In addition, when the ratio of the core portion exceeds 90, the thickness of the sheath portion for maintaining the mechanical properties and weather resistance is reduced, so that the required physical properties of the obtained geogrid for civil engineering tend not to be maintained, which is not preferable. .

  The geogrid for civil engineering of the present invention is obtained by applying resin processing to a base fabric, but the type of the resin is not particularly limited. However, it is preferable to use a vinyl chloride resin, an acrylic resin, an epoxy resin, a vinyl ester resin, an unsaturated polyester resin, a phenol resin or the like in order to maintain good adhesion to the base fabric fiber. These resins may be mixed with additives such as curing agents, accelerators and pigments, and fillers such as talc, gypsum, clay and calcium carbonate as necessary. The resin processing applied to the base fabric is performed by impregnating the base fabric with a resin suitably selected for the base fabric. Specific methods are not particularly limited, and usual means such as dipping, coating, spraying, painting, etc. can be used, and these may be combined.

  The content ratio of the biomass-derived polymer in the geogrid for civil engineering of the present invention needs to be in the range of 25 to 50% by mass with respect to the total mass of the geogrid for civil engineering. When the content ratio of the biomass-derived polymer is less than 25% by mass, for example, the content ratio of a conventional general-purpose polymer such as polyethylene terephthalate is increased, so that the mechanical property of the geogrid for civil engineering tends to be favorable. However, it is not suitable for the environmental impact reduction and carbon neutral viewpoints that are the gist of the present invention, and is not applicable to bioplastics certification. On the other hand, when the content of the biomass-derived polymer exceeds 50% by mass, for example, when the biomass-derived polymer is an aliphatic polyester and is used for fibers constituting the base fabric, the mechanical strength of the obtained geogrid for civil engineering And properties required for weather resistance cannot be maintained.

  Therefore, in the geogrid for civil engineering of the present invention, since the content ratio is in the above range, compared with the conventional geogrid for civil engineering, which is composed of petroleum-based polymers, all the components are incinerated in the atmosphere. The degree of increasing carbon is small, and the effect of reducing global warming can be achieved. Moreover, it becomes possible to hold | maintain the effect with respect to the above environments, the mechanical characteristic calculated | required by the geogrid for civil engineering, workability, etc. with sufficient balance.

Next, although an example explains the present invention, the present invention is not limited to this. In addition, evaluation of the obtained fiber and the geogrid for civil engineering was performed by the following method.
(1) Yarn strength: measured according to JIS L-1069.
(2) Yarn elongation: measured according to JIS L-1069.
(3) Tensile strength: Geogrid was measured according to JIS L-1069, evaluated using a numerical value converted to 1 m width, and 19.6 cN / m or more was regarded as acceptable.

Example 1
Polylactic acid having a melting point of 170 ° C., heat of fusion of 38 J / g, a content ratio of L-lactic acid and D-lactic acid of 98.5 / 1.5 (manufactured by Nature Works), and aromatic polyester having a melting point of 217 ° C. Each chip was dried under reduced pressure using PET in which 15 mol% of isophthalic acid was copolymerized, and then supplied to a concentric core-sheath type compound melt spinning apparatus for melt spinning. At this time, melt-spinning was performed at a spinning temperature of 240 ° C. with a copolymer ratio of 50/50 and a composite ratio (core-sheath mass ratio) of copolymer PET as a sheath and polylactic acid as a core. The obtained composite fiber had a round cross-sectional shape with a fineness of 1100 dtex192 filament, a tensile strength of 5.4 cN / dtex, and a cut elongation of 21.0%. Using a yarn in which two yarns are twisted together as a warp, and using a yarn twisted in one yarn as a weft, the CF is 614 on a rapier loom (the yarn has a core-sheath mass ratio of 50/50 ( The calculation was performed assuming that 1.27 + 1.38) /2=1.325.)). Next, this base fabric was impregnated with a vinyl chloride resin having the following composition, and heat-treated at 150 ° C. for 3 minutes to obtain a geogrid for civil engineering of the present invention.
[Vinyl chloride resin composition]
・ 100 parts of vinyl chloride paste resin (Zeon 121 manufactured by Zeon Corporation)
・ Dioctel phthalate (plasticizer) 40 parts ・ Methyl isobutyl ketone / neftene thinner 10 parts (volume ratio: 1/1, diluent)

(Example 2)
The melt spinning was carried out in the same manner as in Example 1 to obtain a composite fiber having a fine cross-sectional shape of 1670 dtex 192 filament, and the tensile strength of the fiber was 5.6 cN / dtex and the cut elongation was 21.2%. Using a yarn in which five yarns are twisted and twisted for warp and weft, a rapier loom has a CF of 880 (the core yarn specific gravity is 50/50 (1.27 + 1.38) / 2 = 2). The calculation was performed as 1.325.). Next, a vinyl chloride resin was processed on this base fabric in the same manner as in Example 1 to obtain a geogrid for civil engineering of the present invention.

(Comparative Example 1)
The melt spinning was carried out in the same manner as in Example 1 to obtain a composite fiber having a fine cross-sectional shape of 1670 dtex 192 filament, and the tensile strength of the fiber was 5.6 cN / dtex and the cut elongation was 21.2%. Using a single twisted yarn as a warp, a rapier loom with a CF of 920 (the core specific gravity is 50/50 because the core-sheath mass ratio is 50/50) The calculation was performed assuming that 1.27 + 1.38) /2=1.325.)). Next, a vinyl chloride resin was processed on the base fabric in the same manner as in Example 1 to obtain a geogrid for civil engineering.

(Comparative Example 2)
The melt spinning was performed in the same manner as in Example 1 to obtain a composite fiber having a round cross-sectional shape with a fineness of 1100 dtex 192 filaments. The tensile strength of the fiber was 5.6 cN / dtex and the cut elongation was 21.2%. Using a single twisted yarn as a warp and a rapier loom with CF of 317 (the specific gravity of the raw yarn is 50/50 because the core-sheath mass ratio is 50/50) The calculation was performed assuming that 1.27 + 1.38) /2=1.325.)). Next, a vinyl chloride resin was processed on the base fabric in the same manner as in Example 1 to obtain a geogrid for civil engineering.

(Comparative Example 3)
The composite ratio (core-sheath mass ratio) was 95/5, and melt spinning was performed in the same manner as in Example 1 to obtain a composite fiber having a round cross-sectional shape of a fineness of 1400 dtex 210 filaments, and the tensile strength of the fibers was 4.5 cN / dtex. The elongation at break was 27.5%. Using a single twisted yarn as the warp and a rapier loom with a CF of 705 (the core specific gravity is 95/5 (the core-sheath mass ratio is 95/5) The calculation was performed assuming that 1.27 × 0.95 + 1.38 × 0.05) = 1.276. Next, a vinyl chloride resin was processed on the base fabric in the same manner as in Example 1 to obtain a geogrid for civil engineering.

(Comparative Example 4)
As an aromatic polyester, PET copolymerized with 15 mol% of isophthalic acid having a melting point of 217 ° C. was dried under reduced pressure, and then supplied to a melt spinning apparatus to perform melt spinning at a spinning temperature of 240 ° C. The obtained fiber had a round cross-sectional shape with a fineness of 1100 dtex192 filament, a tensile strength of 8.4 cN / dtex, and a cut elongation of 16.4%. A double-twisted woven structure having a CF of 601 was woven with a rapier loom using a single twisted yarn as a weft using a yarn obtained by twisting two of the original yarns as warp. Next, a vinyl chloride resin was processed on the base fabric in the same manner as in Example 1 to obtain a geogrid for civil engineering.
Table 1 shows the results of physical properties measured for each example and comparative example.

From the results of Table 1, Examples 1 and 2 were satisfactory in all items, and physical properties comparable to conventional geogrids for civil engineering were obtained. It can also be said to be an environmentally friendly material. On the other hand, Comparative Example 1 had no problem with the strength required for reinforcement, but because of the large cover factor, the mesh was small and there was no soil bridging or meshing effect through the reinforcing material. In Comparative Example 2, since the cover factor was small, the scale was large, the strength required for the geogrid was not obtained, and the soil slip prevention effect was not achieved. In Comparative Example 3, since the fiber comprising the polymer derived from biomass does not satisfy the structural requirements for both strength and elongation, the obtained geogrid for civil engineering is inferior in strength, such as earth pressure after laying. It was unbearable. In Comparative Example 4, there was no problem in physical properties, but since no biomass-derived polymer was used, the environmental load was not improved.

Claims (3)

A geogrid formed by subjecting a base fabric to resin processing, the base fabric comprising fibers having a strength of 5 cN / dtex or more and an elongation of 25% or less containing a biomass-derived polymer, and a cover of 200 to 900 It has a factor (CF: Formula (1) below) and a quadrilateral mesh-like shape in which one side of the mesh is 3 to 50 mm, and the content ratio of the biomass-derived polymer to the geogrid is 25 to 25 A geogrid for civil engineering, which is 50% by mass.

CF = Td · (Ts / pt) ^1/2 + Yd · (Ys / py) ^1/2 (1)
Td: Vertical weave density (main / 2.54cm)
Yd: Horizontal weave density (main / 2.54cm)
Ts: Warp yarn fineness (decitex)
Ys: Weft yarn fineness (decitex)
pt: specific gravity of the warp yarn material (g / ^cm 3)
py: specific gravity of the weft material (g / cm ³ ) The geogrid for civil engineering according to claim 1, wherein the base fabric is constituted by a core-sheath type composite fiber in which a biomass-derived polymer is disposed in a core part and a petroleum-based polymer is disposed in a sheath part. The geological structure for civil engineering according to claim 1 or 2, wherein the fiber comprising the biomass-derived polymer is a composite fiber having a core-sheath structure, wherein the core part is made of polylactic acid and the sheath part is made of polyethylene terephthalate. grid.