JP2008240199A - Three-dimensional fibrous structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an environmentally friendly three-dimensional fibrous structure which is not a three-dimensional fibrous structure of knitted fabric constitution composed of only a conventional petroleum-derived polymer or biomass-derived polymer but the three-dimensional fibrous structure comprising a biomass-derived polymer in at least a part thereof and capable of offsetting disadvantages such as abrasion resistance of the biomass-derived polymer which is inferior to the petroleum-derived polymer. <P>SOLUTION: The three-dimensional fibrous structure is composed of conjugated fibers having a core-sheath shape. The three-dimensional fibrous structure is characterized in that the core part of the conjugated fibers is formed of the biomass-derived polymer and the sheath part is formed of the petroleum-derived general-purpose polymer and the three-dimensional fibrous structure has ≥90% void ratio. The three-dimensional fibrous structure is characterized in that the core part of the conjugated fibers is formed of polylactic acid and/or the sheath part is formed of polyethylene terephthalate. Furthermore, the three-dimensional fibrous structure is characterized in that the conjugated fibers are concentric core-sheath type conjugated fibers in which the core part and the sheath part of the conjugated fibers are nearly arranged on a concentric circle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a three-dimensional fiber structure composed of a composite fiber having a biomass-derived polymer as a core component, and is used for various cushions, bedding, mats, drainage materials and greening materials used in civil engineering and building fields. The present invention relates to a three-dimensional fiber structure that is applied to a three-dimensional fiber structure and has excellent wear resistance capable of withstanding the use.

  Most of the conventional synthetic fibers are made from limited fossil resources such as petroleum, but in recent years, the fossil resources are not only concerned with the remaining reserves, but also about carbon dioxide generated during incineration disposal. It has become a major social problem as a cause 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.

However, on the other hand, many of the biomass-derived synthetic fibers have the fact that their wear resistance is inferior to that of conventional general-purpose synthetic fibers. As a measure for improving this, for example, on the raw yarn surface, a case of a composite yarn in which a polylactic acid resin is arranged in the core and an aromatic polyester resin is arranged in the sheath is disclosed (for example, Patent Documents 1 and 2). And 3). However, details about specific applications are not described here, and the required characteristics of each material are not mentioned. By the way, about a three-dimensional fiber structure, various aspects are disclosed about the form, a sewing method, etc. (for example, refer patent documents 4-16), However, About these, it is only to the general synthetic fiber which consists of fossil resources. It is not formed with consideration for the environment. Therefore, a three-dimensional fiber structure in which wear resistance, which is a drawback of the biomass-derived polymer, has been not found yet while considering the environment by using the polymer derived from biomass.

JP 2004-353161 A JP 2005-187950 A JP 2005-232627 A Japanese Patent Laid-Open No. 05-187011 Japanese Patent Laid-Open No. 06-305064 Japanese Patent Application Laid-Open No. 07-238459 Japanese Patent Application Laid-Open No. 07-256804 JP 07-258952 A JP 07-289756 A Japanese Patent Laid-Open No. 08-074158 Japanese Patent Laid-Open No. 08-336445 Japanese Patent Laid-Open No. 08-336920 JP 2002-155453 A JP 2004-019059 A JP 2004-027406 A JP 2004-084090 A

  The present invention has been made in view of the current situation as described above, and is not a synthetic fiber composed only of conventional petroleum-derived polymers, but contains biomass-derived polymers at least in part, thereby reducing the amount of carbon dioxide generated. The object of the present invention is to provide a three-dimensional fiber structure that is environmentally friendly and that can compensate for such disadvantages as abrasion resistance, which is inferior to biomass-derived polymers compared to petroleum-derived polymers.

As a result of intensive investigations to solve such problems, the present inventors have obtained from a knitted fabric using a composite fiber in which a sheath part is a petroleum-based general-purpose polymer and a core part is made of a biomass-derived polymer. The three-dimensional fiber structure to be constructed has a reduced environmental burden and has no inferiority in wear resistance, etc., compared to a structure made of only a conventional general-purpose polymer by satisfying predetermined requirements in the configuration. The fact that it can be obtained has been found and the present invention has been reached.
That is, the gist of the present invention is as follows.

(A) A three-dimensional fiber structure composed of a knitted fabric using a composite fiber having a core-sheath shape, wherein the core of the composite fiber is a biomass-derived polymer and the sheath is a petroleum-based general-purpose polymer A three-dimensional fiber structure formed and having a porosity of 90% or more.
(B) The three-dimensional fiber structure according to (a), wherein the core of the composite fiber is formed of polylactic acid.
(C) The three-dimensional fiber structure according to (a) or (b), wherein a sheath portion of the composite fiber is formed of polyethylene terephthalate.
(D) The three-dimensional body according to any one of (a) to (c), wherein the core and sheath of the composite fiber are concentric core-sheath type composite fibers arranged substantially concentrically. Fiber structure.

  The three-dimensional fiber structure of the present invention is different from the conventional three-dimensional fiber structure of a knitted fabric composed only of a petroleum-derived polymer or a biomass-derived polymer, and preferably contains a biomass-derived polymer, so that it can be used at the time of incineration disposal. The amount of generated carbon dioxide can be greatly reduced. In addition, since the three-dimensional fiber structure of the present invention has a three-dimensional knitted fabric structure composed of a core-sheath composite fiber containing a polymer derived from biomass in the core part and a polymer derived from petroleum in the sheath part, it is derived from biomass. Thus, mechanical problems such as wear resistance, which are disadvantages of the polymer, are improved. Furthermore, since the three-dimensional fiber structure of the present invention has a porosity of 90% or more, the cushioning property and the moisture retaining property are good. It will be good. In addition, in the three-dimensional fiber structure of the present invention, the mechanical strength and the like are further improved by using the concentric core-sheath composite fiber.

  Hereinafter, the present invention will be described in detail. The three-dimensional fiber structure of the present invention has a three-dimensional knitted fabric structure, and the production technique thereof is not particularly limited.

  The three-dimensional fiber structure of the present invention needs to have a porosity of 90% or more, preferably 93 to 98%, and more preferably 94 to 98%. When the porosity is less than 90%, cushioning properties, heat retaining properties, filling properties such as earth and sand, and resin are poor in various applications used as a three-dimensional fiber structure. That is, by setting the porosity to 90% or more, for example, when used as a cushioning material, the degree of sinking in the thickness direction at the time of compression increases, so the degree of resilience increases and the cushioning property becomes good. Moreover, the heat retention based on heat insulation becomes favorable by having many air layers. In addition, when used for civil engineering materials, earth and sand etc. are easily filled in the voids, so it can be effectively laid on the foundation ground, and there is no useless space in the ground when buried, so A function that can be effectively stabilized appears. On the other hand, when the porosity is less than 90%, the above function is not exhibited. Moreover, in order to express such a function more effectively, for example, in a knitted fabric configuration including an upper base structure and a connecting yarn, the fineness of the connecting yarn is preferably 200 dtex or more.

  Various methods can be used for controlling the porosity, such as a method of changing the fineness to be used, a method of expanding and contracting in the width and length directions with a heat set, and a method of compressing with a hot press. However, it is not limited to these methods.

  The three-dimensional fiber structure of the present invention needs to be composed of a composite fiber having a core-sheath shape, and the core part of the composite fiber is formed of a biomass-derived polymer, and the sheath part is petroleum-based. It must be formed of a polymer derived from it. As a result, the three-dimensional fiber structure of the present invention is environmentally friendly because it is composed of a composite fiber containing at least a part of the biomass-derived polymer, that is, the core, and the sheath of the composite fiber is a petroleum-based polymer. Therefore, defects such as wear resistance, which is a mechanical problem peculiar to biomass-derived polymers, can be compensated.

  In addition, the conjugate fiber in the present invention is preferably a concentric core-sheath type conjugate fiber in which the core portion and the sheath portion are arranged substantially concentrically. By setting it as such a structure, the effect which distributes a general purpose polymer uniformly to a sheath part can be show | played. If the core portion is eccentric, a thin portion is formed in the sheath general-purpose polymer layer, and the wear resistance tends to decrease at the thin portion, which is not preferable. Such a core-sheath composite fiber can be produced by a known method.

  The petroleum-derived polymer in the present invention is not particularly limited as long as it can be melt-spun. Specifically, polyesters represented by polyalkylene terephthalates such as polyethylene terephthalate (PET), polybutylene terephthalate, polytrimethylene terephthalate: polyamides represented by nylon 6, nylon 66, nylon 46, nylon 11 and nylon 12: Polyolefins typified by polypropylene and polyethylene: Polychlorinated polymers typified by polyvinyl chloride and polyvinylidene chloride: Polytetrafluoroethylene and copolymers thereof, fluorinated fibers typified by polyvinylidene fluoride, etc. . 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 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 biomass-derived monomers such as polylactic acid, PTT (polytrimethylene terephthalate) and PBS (polybutylene succinate), and PHA (polyhydroxyalkanoates) such as polyhydroxybutyric acid And other microorganism production systems. Polylactic acid which is stable in heat resistance and has been 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.

  When polylactic acid is used, L-lactic acid and D-lactic acid are used alone or in combination as described above, but the melting point is 120 ° C. or higher and the heat of fusion is 10 J. / G or more is preferable. For example, the melting point of L-lactic acid and D-lactic acid, which are homopolymers of polylactic acid, is about 180 ° C., but in the case of a copolymer of D-lactic acid and L-lactic acid, the ratio 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 high-strength fibers. Even if fibers are obtained, heat resistance and wear resistance It is not preferable because it becomes inferior to the above. 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.

  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. In addition, 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, hydroxy Examples include heptanoic acid and hydroxyoctanoic acid. Among them, hydroxycaproic acid or glycolic acid is preferred 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. Moreover, when copolymerizing another component with such polylactic acid, it is preferable to make polylactic acid 80 mol% or more. If 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 purpose of the present invention, a heat stabilizer, a crystal nucleating agent, a matting agent, a pigment, a light-proofing agent, a weathering agent, a lubricant, an antioxidant, an antibacterial agent are included in polylactic acid as necessary. Agents, fragrances, plasticizers, dyes, surfactants, flame retardants, surface modifiers, various inorganic and organic electrolytes, and other similar additives may be added.

  Moreover, the well-known additive which shows an effect as a various filler, a thickener, and a crystal nucleating agent can be added to the petroleum-derived general-purpose polymer and biomass-derived polymer in the present invention as necessary. 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, behenic acid amide and other aliphatic amide compounds, aliphatic urea compounds, benzylidene sorbitol compounds, crosslinked polymer polystyrene, rosin metal salts And glass fiber and whiskers. The substance may be added as it is, or may be added after necessary treatment as a nanocomposite. In order to achieve a good price and good physical property balance, an inorganic filler is preferably blended. Moreover, the compounding of a crystal nucleating agent is preferable.

  In the composite fiber according to the present invention, if necessary, colorants such as pigments and dyes, odor absorbers such as activated carbon and zeolite, fragrances such as vanillin and dextrin, stabilizers such as antioxidants and ultraviolet absorbers. , Lubricants, mold release agents, water repellents, antibacterial agents and other secondary additives.

  In the resin composition constituting the conjugate fiber in the present invention, a plasticizer can be used in combination as long as the effects of the present invention are not impaired. By using a plasticizer, it is possible to reduce the melt viscosity during heat processing, especially during extrusion processing, and to suppress a decrease in molecular weight due to shearing heat generation, etc.In some cases, an improvement in crystallization speed can also be expected. Furthermore, when a film or sheet is obtained as a molded product, extensibility and the like can be imparted. Although there is no limitation in particular as a plasticizer, the following can be illustrated. That is, as a plasticizer to be used, an ether plasticizer, an ester plasticizer, a phthalic acid plasticizer, a phosphorus plasticizer and the like are preferable, and an ether plasticizer and an ester plasticizer from the viewpoint of excellent compatibility with polyester. A plasticizer is more preferred.

 Examples of ether plasticizers 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, and adipic acid. 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- Propylene glycol, 1,3-propylene glycol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, dihydric alcohols such as diethylene glycol, neopentyl glycol, polyethylene glycol, and glycerin Trimethylolpropane, it may be mentioned polyhydric alcohols pentaerythritol and the like.

Next, the present invention will be described in detail. In addition, the measuring method and evaluation method of each physical property value in an Example are as follows.
(1) Melting point (° C.) and heat of fusion (J / g) of polylactic acid: A differential scanning calorimeter DSC-2 manufactured by Perkin Elmer was used and measured under conditions of a temperature rising rate of 20 ° C./min.
(2) Content ratio (molar ratio) of L-lactic acid and D-lactic acid in polylactic acid: High-performance liquid chromatography (HPLC) method using an equal mass mixed solution of ultrapure water and 1N sodium hydroxide in methanol as a solvent. It was measured by. Sumichiral OA6100 was used for the column, and it detected with the UV absorption measuring device.
(3) Fiber fineness (dtex): Measured according to JIS L-10153 positive fineness.
(4) Strength (fiber) (cN / dtex): Measured according to JIS L-1013 standard time test for tensile strength and elongation.

(5) Abrasion resistance: A fatigue test was conducted using a dynamic load fatigue tester of JIS-L1021, and the appearance change was observed and evaluated. That is, the fluffing after stepping 10,000 times with a load of 1 kg was observed and evaluated according to the following criteria.
Good: Less fuzz and generally good.
Poor: There is much fuzz and there are concerns about practical use.
(6) Cushioning property: Evaluated by a sensory test. That is, for the cushioning properties when a 20 cm square test product was laid on the buttocks, evaluation by 10 subjects was performed according to the following criteria.
Good: 10 to 7 people judged that the cushioning property was good.
Bad: 6 to 0 people judged that cushioning is good.
(7) Porosity (%): The porosity was calculated by the following formula. The specific gravity of polylactic acid was 1.27, the specific gravity of polyester was 1.38, and the composite fiber multiplied by the ratio was used. (If the core-sheath ratio is 50/50, 1.27 × 0.5 + 1.38 × 0.5 = 1.325)
Porosity (%) = 100− (product mass per 1 m ² ) / (thickness) / (average specific gravity) × 100

(Example 1)
Polylactic acid having a melting point of 170 ° C., heat of fusion of 38 J / g, L / D of 98.5 / 1.5, which is the content ratio of L-lactic acid and D-lactic acid, and aromatic polyester having a melting point of 217 ° C. Each of the chips was dried under reduced pressure using PET copolymerized with 15 mol% of isophthalic acid and then supplied to a concentric core-sheath type composite melt spinning apparatus for melt spinning. At this time, the copolymer PET was arranged so as to be a sheath part and polylactic acid was a core part, the composite ratio (mass ratio) was 50/50, and melt spinning was performed at a spinning temperature of 240 ° C. The obtained conjugate fiber had a round sectional shape of 220 dtex / 48 filament, a tensile strength of 4.3 cN / dtex, and a cut elongation of 28.9%.

  Further, melt spinning was performed on concentric MF core-sheath composite spinning under the same conditions as above, and a monofilament of 220 dtex / 1 filament was obtained. The obtained composite monofilament had a round cross-sectional shape, a tensile strength of 3.8 cN / dtex, and a cut elongation of 34.1%. Next, a three-dimensional mesh fabric was produced using the obtained fibers. Using a warp knitting machine having a 14-gauge double-row needle bed with an improved knitting element capable of knitting a rigid monofilament, upper surface texture is L1 筬, L2 筬 is 220 dtex48 filament, lower surface texture is L5, L6 220 dtex / 48 filaments for both ridges, and a full set of 220 dtex / 1 filament monofilaments was passed through L3 and L4 ridges as connecting yarns for connecting the upper and lower ground structures. A three-dimensional fiber structure was produced.

(Comparative Example 1)
Polylactic acid having a melting point of 170 ° C., a heat of fusion of 38 J / g, and a content ratio of L-lactic acid to D-lactic acid of L / D of 98.5 / 1.5 was dried under reduced pressure. The melt spinning was carried out at a spinning temperature of 240 ° C. The obtained polylactic acid fiber had a round cross-sectional shape with a fineness of 220 dtex / 48 filament, a tensile strength of 4.5 cN / dtex, and a cut elongation of 30.4%. Further, melt spinning was performed on the concentric MF core-sheath composite spinning under the same conditions as above to obtain a monofilament of 220 dtex / 1 filament. The obtained composite monofilament had a round cross-sectional shape, a tensile strength of 3.7 cN / dtex, and a cut elongation of 30.1%. Next, the three-dimensional fiber structure was produced like Example 1 using the obtained fiber.

(Comparative Example 2)
As an aromatic polyester, PET copolymerized with 15 mol% of isophthalic acid having a melting point of 217 ° C. was dried under reduced pressure, then supplied to a melt spinning apparatus, and melt spinning was performed at a spinning temperature of 240 ° C. The obtained polyester fiber had a round cross-sectional shape with a fineness of 220 dtex / 48 filament, a tensile strength of 4.7 cN / dtex, and a cut elongation of 30.2%. Further, melt spinning was performed on the concentric MF core-sheath composite spinning under the same conditions as above to obtain a monofilament of 220 dtex / 1 filament. The obtained composite monofilament had a round cross section, the tensile strength was 3.9 cN / dtex, and the cut elongation was 24.1%. Next, a three-dimensional fiber structure of Comparative Example 2 was produced in the same manner as in Example 1 using the obtained fiber.

(Comparative Example 3)
Example 1 except that the concentric core-sheath composite yarn in Example 1 was changed to 240 dtex / 48 filament, the concentric MF core-sheath composite yarn was changed to 240 dtex / 1 filament, and the porosity was changed to 88%. In the same manner, a three-dimensional fiber structure of Comparative Example 3 was produced.

(Figure 1)

From the results, Example 1 and Comparative Example 2 were satisfactory in all respects such as appearance and wear resistance. However, while Example 1 using a polymer derived from biomass is an environmentally friendly material, Comparative Example 2 is a conventional material with a large environmental load and is not suitable for the purpose of the present invention. . Further, in Comparative Example 1, because of the fiber made only of polylactic acid, the fluff was severe and the wear resistance was poor. In Example 1 and Comparative Example 2, although some fluff was observed but in a practically unproblematic range, Comparative Example 1 was found to be partially broken and practical. It couldn't be tolerated.
Further, in Example 1 and Comparative Examples 1 and 2 in which the porosity was 90% or more, the cushioning property was good, but in Comparative Example 3 that was less than 90%, the cushioning property was poor.

Claims (4)

A three-dimensional fiber structure composed of a knitted fabric using a composite fiber having a core-sheath shape, wherein the core of the composite fiber is formed from a biomass-derived polymer, and the sheath is formed from a petroleum-based general-purpose polymer, A three-dimensional fiber structure having a porosity of 90% or more. The three-dimensional fiber structure according to claim 1, wherein the core of the composite fiber is formed of polylactic acid. The three-dimensional fiber structure according to claim 1 or 2, wherein a sheath portion of the composite fiber is formed of polyethylene terephthalate. The three-dimensional fiber structure according to any one of claims 1 to 3, wherein the composite fiber is a concentric core-sheath type composite fiber in which a core part and a sheath part are arranged substantially concentrically.