JP2008184694A - Fiber aggregate for civil engineering works and construction - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber aggregate for civil engineering works and construction, which is friendly for environment, such as the reduction in generated carbon dioxide, and can eliminate defects, such as inferior abrasion resistance, of products using polymers derived from biomass in comparison with products using polymers derived from petroleum. <P>SOLUTION: This fiber aggregate for the civil engineering works and the construction includes conjugated fibers in which the cross-sectional shape of each fiber has a sheath-core shape, and a sheath portion includes a polymer derived from petroleum and a core portion is derived from biomass. The sheath portion of the conjugated fiber preferably includes polyethylene terephthalate, and the core portion preferably includes polylactic acid. In particular, the fiber aggregate for the engineering works and the construction include sandbags formed of woven fabrics, overland nets and safety nets formed of knitted fabrics, or the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a civil engineering / construction fiber assembly composed of a composite fiber containing a biomass-derived polymer as one component.

  Most of the conventional synthetic fibers are made from precious fossil resources such as petroleum, but in recent years, fossil resources are not only concerned about the shortage of resources, but also the amount of carbon dioxide generated is large in society. It has an influence. Carbon dioxide immobilization is expected to be effective in preventing global warming, and in particular, carbon dioxide-immobilized substances are highly attracting attention and are derived from biomass in order to comply with the Kyoto Protocol that imposes a target value for carbon dioxide reduction. Active use of the material is desired.

  Carbon dioxide produced when biomass-derived synthetic fibers and synthetic resins are burned is originally in the air and does not increase in the atmosphere. This is called carbon neutral and tends to be regarded as important. However, many of the synthetic fibers derived from biomass are inferior to conventional general-purpose synthetic fibers in wear resistance.

  As for composite fibers made of petroleum-derived polymers and biomass-derived polymers, composite fibers in which a polylactic acid-based resin is arranged in the core and an aromatic polyester-based resin is arranged in the sheath have been proposed (for example, Patent Documents). 1-3). However, these are related to raw yarns, and details about specific uses are not described, and required characteristics for each use are not disclosed.

  On the other hand, as for civil engineering / construction fiber assemblies, various types of forms and sewing methods are disclosed (for example, see Patent Documents 4 to 6). However, general synthetic fibers are used for these fiber assemblies, and they are not environmentally friendly.

Further, a method for producing a civil engineering / construction fiber assembly using biomass fibers is also disclosed (see, for example, Patent Documents 7 and 8). However, because these fiber assemblies are made of polylactic acid fibers, they have poor wear resistance, and environmentally friendly and excellent wear resistance for civil engineering / construction fiber assemblies are still not available. Not proposed.
JP 2004-353161 A JP 2005-187950 A JP 2005-232627 A Japanese Patent Laid-Open No. 11-50428 JP 2004-257151 A JP 2005-154982 A JP 2004-183173 A JP 2000-129646 A

  The present invention has been made in view of the current situation as described above, and uses a composite fiber containing at least a part of a polymer derived from biomass, instead of a synthetic fiber consisting only of a conventional petroleum-based polymer. Civil engineering / construction that is environmentally friendly, such as reducing the amount of carbon dioxide generated, and that can eliminate defects such as wear resistance that are inferior to products using biomass-derived polymers compared to products using petroleum-derived polymers It is a technical problem to provide a fiber assembly for use.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have a cross-sectional shape of a core-sheath shape, the sheath is composed of a petroleum-based polymer, and the core is composed of a biomass-derived polymer. It was found that a civil engineering / construction fiber assembly using a composite fiber having excellent wear resistance has reached the present invention.

That is, the gist of the present invention is as follows.
(1) Civil engineering / construction fiber assembly characterized in that the cross-sectional shape is a core-sheath shape, the sheath part is composed of a petroleum-derived polymer, and the core part is composed of a biomass-derived polymer. .
(2) The civil engineering / construction fiber assembly according to (1) above, wherein the sheath of the composite fiber is polyethylene terephthalate and the core is polylactic acid.
(3) The fiber assembly for civil engineering / construction as described in (1) or (2) above, wherein the fiber assembly is an earthenware formed of a woven fabric.
(4) The soilbag as described in (3) above, wherein the cover factor (CF) represented by the following formula (A) of the woven fabric is 1000 or more.
Cover factor (CF) = Td · (Ts / ρt) ^1/2 + Yd · (Ys / ρy) ^1/2 (A)
However,
Td: Warp weave density (main / 2.54cm)
Yd: Weft density (main / 2.54cm)
Ts: warp fineness (decitex)
Ys: Weft fineness (decitex)
ρt: specific gravity of warp material (g / cm ³ )
ρy: specific gravity of the weft material (g / cm ³ )
(5) The fiber assembly for civil engineering / construction as described in (1) or (2) above, wherein the fiber assembly is a land net formed of knitted fabric.
(6) The above (5), characterized in that it comprises a raschel knitted fabric composed of an insertion yarn and a loop yarn, and the fineness ratio (insertion yarn fineness / loop yarn fineness) of the insertion yarn and loop yarn is 1.0 or more. The listed land net.
(7) The civil / construction fiber assembly according to (1) or (2), wherein the fiber assembly is a safety net formed of a knitted fabric.
(8) The above (7), characterized in that it comprises a raschel knitted fabric composed of an insertion yarn and a loop yarn, and the fineness ratio (insertion yarn fineness / loop yarn fineness) of the insertion yarn and loop yarn is 1.0 or more. The safety net described.

  Since the civil engineering / construction fiber assembly of the present invention uses a composite fiber having a core formed of a polymer derived from biomass, it is more than a conventional synthetic fiber composed of a petroleum-based polymer. The amount of carbon dioxide generated at the stage of production and disposal is reduced, and it is environmentally friendly, and physical properties such as abrasion resistance can be improved compared to a fiber assembly using a single fiber derived from a biomass.

  Therefore, according to the present invention, despite the use of a biomass-derived polymer in part and environmentally friendly composite fibers, the physical properties such as wear resistance are good, sandbags, land nets, safety A civil engineering / construction fiber assembly suitable for uses such as a net is provided.

Hereinafter, the present invention will be described in detail.
The civil engineering / construction fiber assembly according to the present invention is composed of a core-sheath type composite fiber having a sheath part made of a petroleum-based polymer and a core part made of a biomass-derived polymer.

  First, the petroleum-derived polymer constituting the sheath portion of the core-sheath type composite fiber used in the present invention is not particularly limited as long as it can be melt-spun. Specifically, polyesters typified by polyalkylene terephthalates such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polytrimethylene terephthalate (PTT) composed of petroleum-derived 1,3-propanediol and terephthalic acid. , Nylon 6, nylon 66, nylon 46, polyamide represented by nylon 11 and nylon 12, polyolefin represented by polypropylene and polyethylene, polychlorinated polymer represented by polyvinyl chloride and polyvinylidene chloride, polytetrafluoroethylene In addition, a fluorinated fiber represented by a copolymer thereof, polyvinylidene fluoride and the like can be used. Of these, low cost polyesters and polyamide polymers are preferred. Moreover, since there are many aliphatic polyesters as a polymer derived from biomass, polyester type is more preferable in consideration of compatibility, and PET is particularly preferable in consideration of cost and handleability.

  In view of viscosity, thermal characteristics, compatibility, polyester polymers include aromatic dicarboxylic acids such as isophthalic acid and 5-sulfoisophthalic acid, adipic acid, succinic acid, suberic acid, sebacic acid, dodecanedioic acid, etc. Aliphatic dicarboxylic acids, and ethylene glycol, propylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and other aliphatic diols, glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxypentane Acids, hydroxycarboxylic acids such as hydroxyheptanoic acid and hydroxyoctanoic acid, and aliphatic lactones such as ε-caprolactone may be copolymerized.

  Next, the biomass-derived polymer constituting the core of the core-sheath type composite fiber used in the present invention is not particularly limited as long as it can be melt-spun. Specifically, biomass-derived monomers such as polylactic acid (PLA), polytrimethylene terephthalate (PTT) and polybutylene succinate (PBS) consisting of biomass-derived 1,3-propanediol and terephthalic acid are chemically treated. Examples thereof include polymers obtained by polymerization and microorganism-producing polymers such as polyhydroxyalkanoates (PHA) such as polyhydroxybutyric acid. Among these, polylactic acid, which has stable heat resistance and is relatively mass-produced, is preferable.

  Examples of polylactic acid include poly D-lactic acid, poly L-lactic acid, poly D, L-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), copolymer of poly D-lactic acid and hydroxycarboxylic acid, copolymer of poly L-lactic acid and hydroxycarboxylic acid, poly D-lactic acid or poly L-lactic acid and aliphatic dicarboxylic acid and aliphatic It is preferable to use a copolymer with a diol or a blend thereof. The polylactic acid is one in which L-lactic acid and D-lactic acid are used alone or in combination as described above. Among them, the melting point is 120 ° C. or more, and the heat of fusion is 10 J / g or more. It is preferable that

  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, the proportion of any component is 10 mol. When it is about%, the melting point is about 130 ° C. Furthermore, when the proportion of any of the components is 18 mol% or more, the melting point is less than 120 ° C. and the heat of fusion is less than 10 J / g, which is almost completely amorphous. When such an amorphous polymer is used, it becomes difficult to heat-stretch particularly in the production process, and it becomes difficult to obtain a high-strength fiber, and even if a fiber is obtained, it is inferior in heat resistance and wear resistance. Since it tends to become a thing, it is not preferable.

  Therefore, as polylactic acid, L / D or D / which is the content ratio (molar ratio) of L-lactic acid and D-lactic acid indicated 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. Among polylactic acids, a mixture (stereo complex) of poly D-lactic acid and poly L-lactic acid as described above is particularly preferable because it has a high melting point of 200 to 230 ° C. and is hardly affected by frictional heat or the like.

  In the case of a copolymer of polylactic acid and hydroxycarboxylic acid, specific examples of hydroxycarboxylic acid include glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxypentanoic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, etc. Can be mentioned. Of these, the use of hydroxycaproic acid or glycolic acid is preferable from the viewpoint of cost. 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. Thus, when making polylactic acid copolymerize another component, it is preferable that polylactic acid shall be 80 mol% or more. When the polylactic acid is less than 80 mol%, the crystallinity of the copolymerized polylactic acid tends to be low, the melting point is less than 120 ° C., and the heat of fusion is less than 10 J / g.

  The molecular weight of the polylactic acid is preferably 1 to 100 (g / 10 min) as measured by a temperature of 210 ° C. and a load of 2160 g according to the 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, strength, wet heat decomposability, and wear resistance are improved. Further, 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.

  In the above-mentioned polylactic acid, as long as the effects of the present invention are not impaired, a heat stabilizer, a crystal nucleating agent, a matting agent, a light-resistant agent, a weathering agent, a fragrance, a surfactant, a flame retardant, Surface modifiers, various inorganic and organic electrolytes, and other similar additives may be added.

  For the above-mentioned petroleum-derived polymers and biomass-derived polymers, known additives that are effective as various fillers, thickeners, and crystal nucleating agents as needed as long as the effects of the present invention are not impaired. Can be added. Specifically, carbon black, calcium carbonate, silicon oxide and silicate, zinc white, high-site clay, kaolin, basic magnesium carbonate, mica, talc, quartz powder, diatomaceous earth, dolomite powder, titanium oxide, zinc oxide , Antimony oxide, barium sulfate, calcium sulfate, alumina, calcium silicate, boron nitride, behenamide, aliphatic amide compounds, aliphatic urea compounds, benzylidene sorbitol compounds, crosslinked polymer polystyrene, rosin metal salts And glass fiber and whiskers. These may be added as they are, or may be added after necessary treatment as a nanocomposite. In order to reduce the price and achieve a good physical property balance, an inorganic filler is preferably blended. Also preferred is a crystal nucleating agent.

  In addition, for petroleum-derived polymers and biomass-derived polymers, if necessary, colorants such as pigments and dyes, odor absorbents such as activated carbon and zeolite, fragrances such as vanillin and dextrin, antioxidants, ultraviolet absorption Stabilizers such as agents, lubricants, mold release agents, water repellents, antibacterial agents and other secondary additives can be blended.

  Furthermore, a plasticizer can be blended with the above petroleum-derived polymer or biomass-derived polymer, if necessary, as long as the effects of the present invention are not impaired. By blending a plasticizer, it is possible to reduce the melt viscosity at the time of heat processing, particularly at the time of extrusion processing, to suppress a decrease in molecular weight due to shearing heat generation and the like, and in some cases, an improvement in crystallization speed can be expected. The type of plasticizer is not particularly limited, but as a plasticizer for a polymer derived from biomass, particularly an aliphatic polyester, an ether plasticizer, an ester plasticizer, a phthalic acid plasticizer, or a phosphorus plasticizer. An ether plasticizer and an ester plasticizer are more preferable from the viewpoint of excellent compatibility with polyester.

  Specific examples of the ether plasticizer include polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Examples of ester plasticizers include esters of aliphatic dicarboxylic acids and aliphatic alcohols. Examples of aliphatic dicarboxylic acids include oxalic acid, succinic acid, sebacic acid, adipic acid, and the like. Examples of aliphatic alcohols include monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, n-hexanol, n-octanol, 2-ethylhexanol, n-dodecanol, stearyl alcohol, ethylene glycol, 1, 2 -Dihydric alcohols such as propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, polyethylene glycol, and glycerin , It may be mentioned trimethylolpropane, polyhydric alcohol pentaerythritol and the like. In addition, two or more kinds of blends selected from copolymers, di-copolymers, tri-copolymers, tetra-copolymers, etc., or their homopolymers, copolymers, etc., comprising a combination of two or more of the above polyether and polyester. Can be mentioned. Furthermore, esterified hydroxycarboxylic acid and the like can also be used. One or a plurality of the above plasticizers can be used as necessary.

  Moreover, as a plasticizer of a petroleum-derived polymer, particularly a polyester such as PET, an ether plasticizer, an ester plasticizer, a phthalic acid plasticizer, a phosphorus plasticizer, or the like is preferable.

  The composite fiber constituting the civil engineering / construction fiber assembly of the present invention has a cross-sectional core-sheath shape, the sheath is formed of the above-described petroleum-based polymer, and the core is derived from the biomass described above. It is necessary to be formed of the polymer. By using such a composite fiber, the polymer derived from biomass is contained in at least a part, that is, in the core part, so that the amount of carbon dioxide generated at the stage of production to disposal is reduced and it is environmentally friendly. In addition, because it is a composite fiber surrounded by a sheath formed of a petroleum-derived polymer in the core, it eliminates defects such as abrasion resistance that are inferior to biomass-derived polymer fibers compared to petroleum-derived polymer fibers can do. Such a core-sheath type composite fiber can be produced by a known method.

  The above-mentioned composite fiber is preferably a concentric core-sheath type composite fiber in which the core portion and the sheath portion are arranged substantially concentrically, and by having such a configuration, a petroleum-derived polymer is formed in the sheath portion. Can be arranged uniformly. When the core portion and the sheath portion are eccentric, a thin portion is formed in the petroleum-derived polymer layer of the sheath portion, but the wear resistance tends to be poor at the thin portion of the polymer layer.

  Moreover, as a ratio of the core part of a core-sheath-type composite fiber mentioned above, and a sheath part, 20 / 80-80 / 20 are preferable by the mass ratio of a core / sheath. When the mass ratio of the core / sheath is less than 20/80, the ratio of the polymer derived from biomass decreases, and the merit of using the polymer derived from biomass such as a carbon dioxide reduction effect is not preferable. On the other hand, if the mass ratio of the core / sheath exceeds 80/20, it is difficult to obtain the improvement in wear resistance which is the object of the present invention. The form of the composite fiber may be either a long fiber or a spun yarn using a short fiber, but a long fiber is preferable for improving wear resistance.

  The form of the civil engineering / construction fiber assembly of the present invention is not particularly limited, and examples thereof include fabrics such as woven fabrics, knitted fabrics, and non-woven fabrics. In addition to the above-mentioned composite fiber, it may be composed of one or more kinds of fibers selected from fibers such as polyamide 6 such as nylon 6 and nylon 66, and aromatic polyester such as PET, PBT, and PTT. Good.

  However, in order to obtain an environment-friendly fiber assembly that can reduce the amount of carbon dioxide generated from the stage of production to disposal, it is preferable to use 50% by mass or more, particularly 70% by mass or more of the above composite fiber.

  The civil engineering / construction fiber assembly of the present invention may be subjected to additional processing such as coating depending on the application. However, when coating is performed, the polymer constituting the base fabric that has been conventionally used is combined with the composite fiber sheath portion. By using it as a petroleum-derived polymer, there is an advantage that a product can be produced by almost the same treatment as before.

Also, in the coating, it is also preferable to use a biomass-derived polymer from the environmental viewpoint, such as polymers obtained by chemically polymerizing monomers derived from biomass such as polylactic acid, PTT and PBS, and PHA such as polyhydroxybutyric acid. More preferable is a coating of a microorganism production system dissolved in an organic solvent or an emulsified solution.
The coating method is not particularly limited, and specifically, a knife coating method, a dipping method, a laminating method, and the like can be employed.

  As a concrete use of the civil engineering / construction fiber assembly of the present invention, for example, a bag material used for dehydration such as sewage sludge, etc. Examples include sandbags, soft ground protective agents, reinforcing grid materials, various drainage materials, erosion prevention materials, water shielding sheets and nets attached to each member, ropes and laces, safety nets, land nets, and the like.

  The above sandbags include general sandbags that are generally filled with earth and sand, large sandbags, water tanks that are filled with superabsorbents, vegetation sandbags that are filled with fertilizer, peat moss, etc. However, these sandbags are preferably formed of woven fabric.

The fabric that forms the sandbag is not particularly limited, and can take various forms depending on the use of the sandbag, and the texture of the fabric can be selected in a timely manner depending on the raw yarn and the situation in which it is used. is there. However, the cover factor (CF) shown in the following (A) of this woven fabric is preferably 1000 or more.
Cover factor (CF) = Td · (Ts / ρt) ^1/2 + Yd · (Ys / ρy) ^1/2 (A)
However,
Td: Warp weave density (main / 2.54cm)
Yd: Weft density (main / 2.54cm)
Ts: warp fineness (decitex)
Ys: Weft fineness (decitex)
ρt: specific gravity of warp material (g / cm ³ )
ρy: specific gravity of the weft material (g / cm ³ )
When the cover factor (CF) is less than 1000, the porosity of the cloth constituting the sandbag is too large, so that not only the earth and sand, polymer absorbent, concrete, etc. that are put into the inside easily come out, but also the eyes of the fabric. It becomes easy to slip.

  The land net, which is a civil engineering / construction fiber assembly, is used at golf courses, driving ranges, various sports fields, etc., and the safety net is used for construction work and civil engineering work. The land net and the safety net are preferably formed of knitted fabric. When these nets are formed of a knitted fabric, not only flexibility can be imparted, but also elongation due to the structure occurs, so that excellent physical properties such as toughness required for these nets can be imparted.

  The knitted fabric forming these nets is not particularly limited, and a knitting structure used for industrial materials can be adopted. More specifically, a raschel knitted, a knotless knitted fabric, a knotted knitted fabric, etc. Can be mentioned. The knitting structure can be selected in a timely manner depending on the raw yarn and the conditions of use, but Russell knitting and no-knot knitted fabric other than the knot knitting where stress concentrates on the knot portion are more preferable. When straight line strength is required, knotless knitting is preferable, and when the use situation is severe and part of the net is damaged, or when the straight line strength of the raw yarn is relatively weak, but the knot strength is good For example, it is preferable to apply a Russell knitting composed of loops.

  The raschel knitted fabric composed of the insertion yarn and the loop yarn preferably has a fineness ratio (insertion yarn fineness / loop yarn fineness) of the insertion yarn and the loop yarn of 1.0 or more. When the fineness ratio is less than 1.0, for example, when a raw yarn having the same strength is used, the knitted fabric strength is satisfied, but a strong portion beyond the cutting of the insertion yarn becomes unnecessary. That is, the unnecessary portion of the loop yarn increases the mass of the knitted fabric. With the aging of on-site workers and the need to reduce the weight of materials, it is unsuitable for the current situation.

Next, the present invention will be specifically described with reference to examples. In addition, each physical property in an Example was measured and evaluated by the following method.
(1) Melting point of polylactic acid (° C.), heat of fusion (J / g)
A differential scanning calorimeter DSC-2 manufactured by Perkin Elmer was used, and the measurement was performed under the condition of a heating rate of 20 ° C./min.
(2) Content ratio (molar ratio) of L-lactic acid and D-lactic acid in polylactic acid
It measured by the high performance liquid chromatography (HPLC) method by using the equal mass mixed solution of the ultrapure water and the methanol solution of 1N sodium hydroxide as a solvent. Sumichiral OA6100 was used for the column, and it detected with the UV absorption measuring device.
(3) Fiber fineness (dtex)
It measured according to JIS L-1013 positive fineness.
(4) Strength (fiber) (cN / dtex)
It measured according to the standard time test of JIS L-1013 tensile strength and elongation.
(5) Strong ((knitted fabric) (N)
Regarding raschel knitting The knitted fabric having a knitted structure with a total fineness of less than 5,000 dtex conforms to the method of 6.11.1 (a) of 6.11, JIS L 1043. The measurement was performed at a tensile speed of 200 mm / min according to the method 6.11.1 (b). For knotless knitted fabric (penetrating type), the knitting yarn in the other direction is cut along the direction of the original yarn (straight line) (the knitting yarn length in the other direction is cut to 1 cm). Measurements were taken at speed.

(6) Abrasion resistance A test was performed in accordance with the abrasion resistance test of JIS D-4604. A load of 1.25% of the strength value of the sample was hung on one end of the sample (knitted fabric or woven fabric), the other end was passed over a round file, and then fixed to the vibrating drum. Next, the vibrating drum was reciprocated by a crank and a crank arm, and the sample was repeatedly worn 30 times per minute, 5,000 times, and the appearance of the sample was observed.
(7) Implementation test 1 (for safety net and land net)
The end of the knitted fabric was sewed three times while passing through the rope so that the tailored dimensions were 4m x 4m. Check the mass of the net after tailoring, hold the net with a 15% (60 cm) sag, spread it horizontally on the steel frame, and expose it for half a year. Observed.

(8) Implementation test 2 (for civil engineering and construction)
For civil engineering materials tailored to 4.7 x 3.2 m, 8 tons of human-sized walnut stone, and for civil engineering materials tailored to 3.0 x 2.0 m, 2 tons Each of them was dropped twice from 1m height, and the damage of civil engineering materials was observed.
(9) Implementation test 3 (for sandbags)
The raw cloth for clay was cut into a width of 50 cm × 122 cm, bent from the center, and sewn at both ends to prepare a 48 cm × 60 cm bag. 20 kgf of earth and sand was placed in the bag and allowed to fall freely 10 times from above 2 m, and the state after dropping was visually observed.
(10) Implementation test 4 (for sandbags)
According to JIS Z1651, a flexible container having a round shape and a two-point belt suspension with a peripheral diameter of 1200 mm and a height of 1200 mm was prepared, and this was used as a large soil container. 2000 kgf of earth and sand was put into the bag body, and it was allowed to fall freely from above 2 m, and the state after dropping was visually observed.

(Example 1)
Polylactic acid (PLA) having a melting point of 170 ° C., a heat of fusion of 38 J / g, and a content ratio (molar ratio) of L-lactic acid to D-lactic acid of 98.5 / 1.5 is aromatic. As polyester, copolymerized PET obtained by copolymerizing 15 mol% of isophthalic acid having a melting point of 217 ° C. was dried under reduced pressure, and then supplied to a concentric core-sheath type composite melt spinning apparatus to perform melt spinning. At this time, melt spinning was performed at a spinning temperature of 240 ° C. with a copolymer / PET being a sheath and a polylactic acid being a core so that the core / sheath mass ratio was 50/50. The obtained composite fiber had a round cross-sectional shape with a fineness of 1560 dtex 140 filament, a tensile strength of 4.3 cN / dtex, and a cut elongation of 28.9%.

Next, the obtained composite fiber was used as an insertion yarn and a loop yarn, and a knitted fabric was produced with a 9G Russell knitting machine so that the knitting configuration would be 13 real (10 mm on a side).

(Example 2)
Using the conjugate fiber obtained in Example 1, a knotless knitted fabric in which 10 pieces were twisted together using a knotless knitting machine was produced (one side 25 mm).
(Example 3)
Melt spinning was performed in the same manner as in Example 1 to obtain two types of composite fibers having a round cross-sectional shape and a fineness of 1560 dtex 140 filaments and 1670 dtex 140 filaments. All of these composite fibers had a tensile strength of 4.3 cN / dtex and a cut elongation of 28.9%.

Next, using a 1560 dtex 140 filament yarn as an insertion yarn and a 1670 dtex 140 filament yarn as a loop yarn, a knitted fabric was produced with a 9G Russell knitting machine so that the knitting configuration would be 13 full scales (10 mm per side).

(Comparative Example 1)
Only the polylactic acid used in Example 1 was supplied to the melt spinning apparatus, and melt spinning was performed at a spinning temperature of 240 ° C. The obtained polylactic acid fiber had a round cross-sectional shape with a fineness of 1430 dtex, a tensile strength of 4.5 cN / dtex, and a cut elongation of 30.9%.
Next, knitting was performed in the same manner as in Example 1 using the obtained fiber to obtain a knitted fabric.
(Comparative Example 2)
Using the fibers used in Comparative Example 1, knitting was performed in the same manner as in Example 2 to obtain a knitted fabric.
(Comparative Example 3)
Only the copolymerized PET used in Example 1 was supplied to a melt spinning apparatus, and melt spinning was performed at a spinning temperature of 240 ° C. The obtained fiber had a round cross-sectional shape with a fineness of 1430 dtex, a tensile strength of 4.5 cN / dtex, and a cut elongation of 27.8%.
Next, knitting was performed using this fiber in the same manner as in Example 1 to obtain a knitted fabric.

  Table 1 shows the knitted fabrics obtained in Examples 1 to 3 and Comparative Examples 1 to 3 and the results of evaluating the knitted fabrics as a land net and a safety net.

As is clear from Table 1, the knitted fabrics obtained in Examples 1 to 3 can satisfy all evaluation items such as wear resistance, and are excellent for land nets and safety nets. Because it uses a composite fiber using polylactic acid, a polymer derived from biomass, it was an environmentally friendly material. In addition, the knitted fabric of Example 1 in which the fineness ratio of the insertion yarn and the loop yarn is 1 is almost equal in strength to the knitted fabric of Example 3 in which the fineness ratio is 0.93, but the total weight is about It was as light as 5%.
On the other hand, the knitted fabrics obtained in Comparative Examples 1 and 2 had poor wear resistance and could not withstand practical use. In addition, the knitted fabric of Comparative Example 3 using fibers made of copolymerized PET, which is a petroleum-derived polymer, has good evaluation items such as abrasion resistance, but is not an environmentally friendly material.

Example 4
A polylactic acid having a melting point of 170 ° C., a heat of fusion of 38 J / g, a content ratio (molar ratio) of L-lactic acid to D-lactic acid of 98.5 / 1.5, and an aromatic polyester Using a copolymerized PET obtained by copolymerizing 15 mol% of isophthalic acid having a melting point of 217 ° C., each chip was dried under reduced pressure, and then supplied to a concentric core-sheath type composite melt spinning apparatus to perform melt spinning. At this time, melt spinning was performed at a spinning temperature of 240 ° C. with a copolymer PET being a sheath and polylactic acid being a core, a core / sheath mass ratio of 50/50. The obtained conjugate fiber had a round cross-sectional shape with a fineness of 1430 dtex 210 filament, a tensile strength of 4.3 cN / dtex, and a cut elongation of 28.9%.

  Next, a knitted fabric was produced using this composite fiber so that the knitting structure would be 13 full-scale with a 9G Russell knitting machine (one side 25 mm). Two pieces of this knitted fabric cut to 3.0 m x 4.0 m are overlapped and folded in half so as to be about 3.0 x 2.0 m, leaving the side facing the two folds as an opening. Then, the two sides of the side part were stitched together and tied together to form a drawstring bag. Next, a nylon rope having a thickness of 6 mm (tensile strength: 0.75 t) was inserted as a tying rope along the entire circumference of the opening part into the stitches below the opening part by three stitches. Similarly, along the entire circumference of the opening, a 22 mm thick polyester rope (tensile strength: 6.3 t) is inserted as a suspension rope into the stitches at the bottom of the fifth stitch from the opening, and civil engineering / construction materials are used. Obtained.

(Example 5)
Using the conjugate fiber obtained in Example 4, a knitted fabric was produced with a 9G Russell knitting machine so that the knitting structure would be 103 (one side 75 mm). Two pieces of this knitted fabric cut to 4.7 m x 6.4 m are overlapped and folded in half so as to be about 4.7 x 3.2 m, leaving the side facing the double fold as an opening. Then, the two sides of the side part were stitched together and tied together to form a drawstring bag.
Next, a nylon rope having a thickness of 6 mm (tensile strength: 0.75 t) was inserted as a tying rope along the entire circumference of the opening part into the stitches three stitches below the opening part. Similarly, along the entire circumference of the opening, a 30 mm thick polyester rope (tensile strength: 12.0 t) is inserted as a hanging rope into the stitches at the bottom of the fifth stitch from the opening, and civil engineering / construction materials are placed. Obtained.

(Example 6)
Using the conjugate fiber obtained in Example 4, a knotless knitted fabric in which 10 pieces were twisted using a knotless knitting machine was produced (one side 25 mm). Using the obtained knitted fabric, sewing was carried out in the same manner as in Example 10 to obtain civil engineering / construction materials.
(Example 7)
Civil engineering was carried out in the same manner as in Example 10 except that the conjugate fiber obtained in Example 4 was used and a knitted fabric was produced with a 9G Russell knitting machine so that the knitting structure was 5 real (one side 25 mm).・ We made construction materials.

(Comparative Example 4)
Only the polylactic acid used in Example 4 was supplied to the melt spinning apparatus, and melt spinning was performed at a spinning temperature of 240 ° C. The obtained polylactic acid fiber had a round cross-sectional shape with a fineness of 1430 dtex, a tensile strength of 4.5 cN / dtex, and a cut elongation of 30.9%.
Using the obtained polylactic acid fiber, knitting and sewing were performed in the same manner as in Example 4 to obtain civil engineering / construction materials.
(Comparative Example 5)
Using the polylactic acid fiber obtained in Comparative Example 4, knitting and sewing were performed in the same manner as in Example 5 to obtain civil engineering / construction materials.
(Comparative Example 6)
Using the polylactic acid fiber obtained in Comparative Example 4, knitting and sewing were performed in the same manner as in Example 6 to obtain civil engineering / construction materials.

(Comparative Example 7)
Only the copolymerized PET used in Example 4 was supplied to a melt spinning apparatus, and melt spinning was performed at a spinning temperature of 240 ° C. The obtained copolymer PET fiber had a round cross-sectional shape with a fineness of 1430 dtex, a tensile strength of 4.5 cN / dtex, and a cut elongation of 27.8%.
Using the obtained copolymerized PET fiber, knitting and sewing were performed in the same manner as in Example 4 to obtain civil engineering / construction materials.
(Comparative Example 8)
Using the copolymerized PET fiber obtained in Comparative Example 7, knitting and sewing were performed in the same manner as in Example 5 to obtain civil engineering / construction materials.
(Comparative Example 9)
Using the copolymerized PET fiber obtained in Comparative Example 7, knitting and sewing were performed in the same manner as in Example 6 to obtain civil engineering / construction materials.

  The evaluation results of the civil engineering / construction materials obtained in Examples 4 to 7 and Comparative Examples 4 to 9 are shown in Tables 2 and 3.

As is clear from Tables 2 and 3, the civil engineering / construction materials obtained in Examples 4 to 6 are satisfactory in all evaluation items such as wear resistance and are obtained in Example 7. The civil engineering / construction materials had a slightly lower knitted fabric strength, but had utility as civil engineering / construction materials. In addition, since these materials use composite fibers using polylactic acid, which is a polymer derived from biomass, they were environmentally friendly materials.
On the other hand, the civil engineering / construction materials obtained in Comparative Examples 4 to 6 had poor wear resistance and could not withstand practical use. In addition, the civil engineering / construction materials of Comparative Examples 7 to 9 using fibers made of copolymerized PET, which is a petroleum-derived polymer, have good evaluation items such as wear resistance, but are not environmentally friendly materials.

(Example 8)
A polylactic acid having a melting point of 170 ° C., a heat of fusion of 38 J / g, a content ratio (molar ratio) of L-lactic acid to D-lactic acid of 98.5 / 1.5, and an aromatic polyester Using a copolymerized PET obtained by copolymerizing 15 mol% of isophthalic acid having a melting point of 217 ° C., each chip was dried under reduced pressure, and then supplied to a concentric core-sheath type composite melt spinning apparatus to perform melt spinning. At this time, melt spinning was performed at a spinning temperature of 240 ° C. with a copolymer PET being a sheath and polylactic acid being a core, a core / sheath mass ratio of 50/50. The obtained composite fiber had a round cross-sectional shape with a fineness of 280 dtex48 filament, a tensile strength of 4.3 cN / dtex, and a cut elongation of 28.9%.

This composite fiber was used for warp and weft, and weaved at a weaving density of 41 pieces / 2.54 cm in both warp and weft with a rapier loom to obtain a fabric for earthenware. The cover factor (CF) of this fabric was 1192. (Since the mass ratio of the composite fiber is 50/50, the specific gravity of the fiber was calculated as (1.27 + 1.38) /2=1.325.)

Example 9
Each chip was prepared using the polylactic acid used in Example 8 as an aromatic polyester, and copolymerized PET obtained by copolymerizing 15% by mole of isophthalic acid having a melting point of 217 ° C. and kneading 1.5% of carbon black. After drying under reduced pressure, it was supplied to a concentric core-sheath type composite melt spinning apparatus to perform melt spinning. At this time, melt spinning was performed at a spinning temperature of 240 ° C. with a copolymer PET being a sheath and polylactic acid being a core, a core / sheath mass ratio of 50/50. The obtained conjugate fiber had a round cross-sectional shape with a fineness of 1670 dtex192 filament, a tensile strength of 4.5 cN / dtex, and a cut elongation of 30.1%.

This composite fiber was used for warp and weft, and weaved at a weave density of 22 / 2.54 cm in both warp and weft with a rapier loom to obtain a fabric for earthenware. The cover factor (CF) of this fabric was 1562.

(Example 10)
The composite fiber obtained in Example 8 was used for warp and weft, and weaved at a weaving density of 32 / 2.54 cm in both warp and weft with a rapier loom to obtain a fabric for earthenware. The cover factor (CF) of this fabric was 930.
(Comparative Example 10)
Only the polylactic acid used in Example 8 was supplied to the melt spinning apparatus, and melt spinning was performed at a spinning temperature of 240 ° C. The obtained polylactic acid fiber had a round cross-sectional shape with a fineness of 280 dtex48 filament, a tensile strength of 4.5 cN / dtex, and a cut elongation of 30.9%.

Using the obtained polylactic acid fiber, weaving was performed in the same manner as in Example 8 to obtain a fabric for earthenware. The cover factor (CF) of this fabric was 1218.
(Comparative Example 11)
Only the copolymerized PET used in Example 8 was supplied to a melt spinning apparatus, and melt spinning was performed at a spinning temperature of 240 ° C. The obtained copolymerized PET fiber had a round cross-sectional shape with a fineness of 280 dtex48 filaments, a tensile strength of 4.5 cN / dtex, and a cut elongation of 27.8%.
Using the obtained copolymerized PET fiber, weaving was performed in the same manner as in Example 8 to obtain a woven fabric for earthenware. The cover factor (CF) of this fabric was 1168.

  Table 4 shows the evaluation results of the sandbag fabrics obtained in Examples 8 to 10 and Comparative Examples 10 and 11.

As is clear from Table 4, the soil woven fabric obtained in Examples 8 and 9 satisfies all the evaluation items such as abrasion resistance, and the soil woven fabric obtained in Example 10 is satisfactory. The cover factor (CF) was slightly small, but it had practicality as a sandbag. In addition, these sandbag fabrics are environmentally friendly materials because they use a composite fiber using polylactic acid, which is a polymer derived from biomass.
On the other hand, the clay woven fabric obtained in Comparative Example 10 has poor wear resistance and could not withstand practical use. In addition, the sandbag fabric of Comparative Example 11 using fibers made of copolymerized PET, which is a petroleum-derived polymer, has good evaluation items such as abrasion resistance, but is not an environmentally friendly material.

Claims (8)

  A civil engineering / construction fiber assembly characterized in that the cross-sectional shape is a core-sheath shape, the sheath portion is composed of a petroleum-derived polymer, and the core portion is composed of a biomass-derived polymer.   2. The civil engineering / construction fiber assembly according to claim 1, wherein the sheath of the composite fiber is polyethylene terephthalate and the core is polylactic acid.   The fiber assembly for civil engineering / construction according to claim 1 or 2, wherein the fiber assembly is a sandbag made of woven fabric. The sandbag according to claim 3, wherein the cover factor (CF) shown in the formula (A) of the fabric is 1000 or more.
Cover factor (CF) = Td · (Ts / ρt) ^1/2 + Yd · (Ys / ρy) ^1/2 (A)
However,
Td: Warp weave density (main / 2.54cm)
Yd: Weft density (main / 2.54cm)
Ts: warp fineness (decitex)
Ys: Weft fineness (decitex)
ρt: specific gravity of warp material (g / cm ³ )
ρy: specific gravity of the weft material (g / cm ³ )   The civil engineering / construction fiber assembly according to claim 1 or 2, wherein the fiber assembly is a land net formed of knitted fabric.   The land net according to claim 5, wherein the land net comprises a raschel knitted fabric comprising an insertion yarn and a loop yarn, and the fineness ratio (insertion yarn fineness / loop yarn fineness) of the insertion yarn and the loop yarn is 1.0 or more. .   The fiber assembly for civil engineering / construction according to claim 1 or 2, wherein the fiber assembly is a safety net formed of knitted fabric. 8. The safety net according to claim 7, wherein the safety net is made of a Russell knitted fabric including an insertion yarn and a loop yarn, and a fineness ratio (insertion yarn fineness / loop yarn fineness) of the insertion yarn and the loop yarn is 1.0 or more. .