JP2010227035A - Fiber material for culturing seaweed - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide fiber material for culturing seaweed suitable for production of culturing material having good seaweed-adhesive properties and root-taking properties, and favorably usable even in a place under severe wave conditions. <P>SOLUTION: The fiber material for culturing seaweed is used in water, and comprises lines of thread obtained by collecting a plurality of fibers twisted or not twisted. The lines of thread contain at least heat-fusible conjugate fibers. The heat-fusible conjugate fibers include a polylactic acid polymer having a high melting point and a polylactic acid polymer having a melting point lower than that of the high-melting-point polylactic acid polymer by ≥20°C. The low-melting-point polylactic acid polymer occupies at least part of the surface of the heat-fusible conjugate fiber, and the fibers forming the line of thread are mutually and thermally bonded via the melted or softened low-melting-point polylactic acid polymer. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a seaweed aquaculture fiber material used in water, and particularly to a seaweed aquaculture fiber material that has good adhesion and entrapment of seaweeds and can be suitably used even in severe wave conditions. .

  Conventionally, biodegradable fibers that reduce environmental impact are used as aquaculture nets for aquaculture of seaweeds such as seaweed, and the surface of biodegradable fibers is covered with polyvinyl alcohol resin to make it easier for the nori spores to adhere and grow A seaweed aquaculture net is known (Patent Document 1).

  Similarly, twisted yarns with different fineness, such as polylactic acid fiber, which is effective for reducing environmental impact, such as thickness, mediumness, and fineness, are twisted together. Seedlings and yarns from which spores are less likely to fall off are known (Patent Document 2).

  However, among the above conventional seaweed aquaculture materials, the seaweed aquaculture net with the surface of biodegradable fibers coated with polyvinyl alcohol resin is used in places with severe wave conditions such as outside the bay, the fiber surface coating resin is Since the polymer species is different from that of the biodegradable polymer, it is assumed that polyvinyl alcohol resins that are considered not to be sufficiently compatible with each other fall off from the biodegradable fiber and the spores of the seaweed are reduced. Moreover, when the method of twisting twisted yarns having different finenesses is used in a place where the wave conditions are severe, it is considered that the yarn breaks and spores fall off.

JP-A-9-96 JP 2006-129741 A

  The present invention provides a fiber material for aquaculture of seaweeds that solves the above problems and is suitable for obtaining aquaculture materials that have good adhesion and viability for seaweeds and that can be suitably used even in places with severe wave conditions. Is.

  The present invention is a fiber material for seaweed culture used in water, wherein the fiber material is a yarn in which a plurality of fibers are bundled without twisting or a plurality of fibers are twisted and gathered, and the yarn The strip contains at least a heat-fusible conjugate fiber, and the heat-fusible conjugate fiber has a high melting point polylactic acid polymer and a low melting point having a melting point that is 20 ° C. lower than the melting point of the high melting point polylactic acid polymer. A low-melting-point polymer composed of a polylactic acid-based polymer, wherein the low-melting-point polylactic acid-based polymer occupies at least a part of the surface of the heat-fusible composite fiber, and the fibers constituting the yarn are melted or softened. The gist of the present invention is a fiber material for seaweed aquaculture that is thermally bonded via a lactic acid polymer.

  Hereinafter, the present invention will be described in detail.

  Specifically, the fiber material for seaweed culture of the present invention is a thread for constituting seaweed culture material (culture net, rope, twisted yarn, etc.) for attaching seaweed and growing it in water. In this case, the plurality of fibers are bundled without twisting, or the plurality of fibers are twisted and bundled. The yarn contains at least a heat-fusible conjugate fiber.

  The heat-fusible conjugate fiber used in the present invention is composed of a high-melting polylactic acid polymer and a low-melting polylactic acid polymer having a melting point 20 ° C. lower than the melting point of the high-melting polylactic acid polymer, The low melting point polylactic acid polymer occupies at least a part of the surface of the composite fiber.

  In the present invention, the polylactic acid polymer is poly-D-lactic acid, poly-L-lactic acid, a copolymer of D-lactic acid and L-lactic acid, a copolymer of D-lactic acid and hydroxycarboxylic acid, Examples thereof include a polymer selected from the group consisting of a copolymer of L-lactic acid and hydroxycarboxylic acid, and a copolymer of D-lactic acid, L-lactic acid and hydroxycarboxylic acid. Examples of hydroxycarboxylic acids include glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid, hydroxyheptanoic acid, hydroxyoctanoic acid, etc. Among these, hydroxycaproic acid or glycolic acid should be used. Is preferable from the viewpoint of low cost.

  Poly-L-lactic acid and poly-D-lactic acid, which are homopolymers of polylactic acid, have a melting point of about 180 ° C. However, when the copolymer is used as a polylactic acid polymer, the practicality and melting point are taken into consideration. It is preferable to determine the copolymerization amount ratio of the polymer components. The control of the melting point of the polylactic acid polymer will be described below. The lactic acid monomer that constitutes polylactic acid has optically active carbon, and there exist optical isomers of D-form and L-form. When the L form is copolymerized with less than 1 mol% of the D form, the melting point is 170 ° C. or more, when the L form is copolymerized with less than 2 mol% of the D form, the melting point is 165 ° C. or more, and when the D form is copolymerized with 8 mol%, the melting point When the D form is copolymerized at about 130 ° C. and 12 mol%, the melting point can be controlled such that the melting point is 110 ° C. When the amount of copolymer of L-form is larger than that of D-form, and the D-form is 18 mol% or more (however, it does not exceed the amount of copolymerization of L-form), no clear crystalline melting point is observed, and softening temperature is 90 ° C Less amorphous strong polymer. In the present invention, when a copolymer of D-form and L-form is used, the copolymerization molar ratio of the employed copolymer is D-form / L-form (copolymerization mole ratio) = 100-82 / 0-18. Alternatively, when it is 0 to 18/100 to 82, a material having a practical melting point can be obtained.

  Further, as the polylactic acid polymer used in the present invention, polylactic acid having a stereocomplex having a melting point of 190 ° C. to 235 ° C. can be used. The polylactic acid forming the stereocomplex has 30/70 to 70/30 of poly-L-lactic acid having an optical purity of 70% to 100% and poly-D-lactic acid having an optical purity of 70% to 100%. It can be obtained by blending at a ratio (mass ratio). If the optical purity of poly-L-lactic acid or the optical purity of poly-D-lactic acid is less than 70%, formation of a stereocomplex that is a stereospecific bond is inhibited, and the crystal melting start temperature of the blended polylactic acid It is difficult to set the temperature to 190 ° C. or higher. When the blend ratio of poly-L-lactic acid and poly-D-lactic acid is out of the range of 30/70 to 70/30 (mass ratio), the stereocomplex that is stereospecific is the same as described above. Formation is inhibited, and it becomes difficult to make the crystal melting start temperature of polylactic acid 190 ° C. or higher. A more preferable blend ratio is 40/60 to 60/40. As a specific method for obtaining polylactic acid in which a stereo complex is formed by blending poly-L-lactic acid and poly-D-lactic acid, poly-L-lactic acid and poly-D-lactic acid are individually melted. Examples thereof include a method of uniformly kneading, a method of mixing poly-L-lactic acid pellets and poly-D-lactic acid pellets as uniformly as possible, and then melting them, and any method may be used.

  The polylactic acid polymer used in the present invention includes various inorganic particles such as titanium oxide, silicon oxide, calcium carbonate, silicon nitride, clay and talc, crosslinked polymer particles, various metal particles, etc., depending on the application. In addition to these particles, conventionally known additives such as anti-aging agents, antioxidants, anti-coloring agents, light resistance agents, inclusion compounds, antistatic agents, various coloring agents, various surfactants, various reinforcing fibers, etc. May be added as long as the effects of the present invention are not impaired.

  The heat-fusible conjugate fiber used in the present invention is composed of a high melting point polylactic acid polymer and a low melting point polylactic acid polymer, and the low melting point polymer occupies at least a part of the surface of the conjugate fiber. is there. Such a composite form includes a core-sheath type in which a low melting point polylactic acid polymer is disposed in a sheath and a high melting point polylactic acid polymer in a core, and a low melting point polylactic acid polymer and a high melting point polylactic acid polymer. The side-by-side type, in which the coalesced materials are bonded together, the sea-island type in which the high-melting-point polylactic acid-based polymer is arranged in many islands, the low-melting-point polylactic acid-based polymer in the sea, and the radiation type and multi-leaf type Examples thereof include a fine mold. In the present invention, it is preferable to adopt a core-sheath type composite form in consideration of the adhesiveness between fibers and the strength of the obtained fiber material for seaweed aquaculture.

  The difference in melting point between the high melting point polylactic acid polymer and the low melting point polylactic acid polymer is 20 ° C. or more (in addition, the polylactic acid polymer is highly amorphous and has no clear melting point. The visual softening temperature is considered the melting point.) If the difference between the melting points of the two is less than 20 ° C., even the high melting point polylactic acid polymer is softened or melted in the heat treatment process and the fiber form cannot be maintained. As a result, the molten polylactic acid polymer flows. Then, it is hardened in one place or falls off, and the bonding area becomes small, and the fibers cannot be effectively bonded to each other. Moreover, since a high melting point polylactic acid-type polymer does not maintain a fiber form, fiber strength falls. By setting the difference in melting point between the two to 20 ° C. or more, only the low melting point polylactic acid polymer is melted by heat treatment to bond the fibers together, while the high melting point polylactic acid polymer is affected by heat. Therefore, the mechanical strength and flexibility can be improved both in the dry state and in the wet state.

  In order to make the difference between the melting points of 20 ° C. or more, the polylactic acid may be appropriately selected and combined from the above-mentioned polylactic acids. For example, a high melting point polylactic acid polymer having a melting point of 170 ° C. or more (98 mol% L-form) As mentioned above, the combination of D isomer less than 2 mol%) and a low melting point polylactic acid polymer having a melting point of 155 to 110 ° C. (L isomer 82 to 95 mol%, D isomer 5 to 18 mol%). In addition, a high melting point polylactic acid-based polymer in which a stereocomplex having a melting point of 200 ° C. or higher or a crystal melting start temperature of 180 ° C. or higher is formed, and a poly-L having a relatively low D copolymer amount of 160 ° C. to 170 ° C. -Combination with lactic acid is also possible. In the combination of polylactic acid polymers, a high melting point polylactic acid polymer having a melting point of 110 ° C. or higher, and a low melting point polylactic acid polymer having a softening point of less than 90 ° C. Although a combination such as a lactic acid polymer may be used, it is difficult to perform sufficient heat setting in the heat setting process in the fiber manufacturing process, and thus the heat-fusible fiber itself is likely to be thermally contracted.

  A polylactic acid polymer formed by forming a stereocomplex having a melting point of 200 ° C. or higher or a crystal melting start temperature of 180 ° C. or higher is arranged in the core, and poly-L-lactic acid having a melting point of about 160 ° C. to 170 ° C. is used as the sheath. Since the core-sheath type composite fiber arranged can be heat-set at a high temperature at the time of fiber production, the resulting heat-fusible fiber is not subject to thermal shrinkage during heat treatment such as heat bonding treatment at the time of material production. Stable heat treatment can be performed without generating. The obtained material is preferable since the appearance of the surface is not disturbed due to texture hardening or unevenness generation. The crystal melting start temperature is a melting endotherm when a melting endotherm is drawn with a differential scanning calorimeter (Perkin Elmer, Diamond DSC, automatically measured at a heating rate of 20 ° C./min) (see FIG. 1). The point a at which crystal melting starts in the curve is indicated, and the crystal melting start temperature of 180 ° C. means that the temperature at the point a is 180 ° C. The term “polylactic acid polymer has crystallinity” means that a clear endothermic peak is drawn when a melting endothermic curve is drawn with a differential scanning calorimeter.

  The intrinsic viscosities of the high melting point polylactic acid polymer and the low melting point polylactic acid polymer may be appropriately selected depending on the spinning equipment, fiber physical properties and the like, and are not particularly limited.

  The composite ratio (mass ratio) of the high-melting point polylactic acid polymer and the low-melting point polylactic acid polymer constituting the heat-fusible conjugate fiber may be appropriately determined in consideration of thermal adhesiveness, etc. The range is 70/30 to 30/70, preferably 60/40 to 40/60. By setting the composite ratio of the high melting point polylactic acid-based polymer to 30 parts by mass or more, the strength of the yarn can be maintained, and the resulting fiber material has a good handleability without being cured. be able to. On the other hand, by setting the composite ratio of the high melting point polylactic acid polymer to 70 parts by mass or less, the ratio of the low melting point polylactic acid polymer that is an adhesive component does not decrease too much. Therefore, it is possible to obtain a material in which the fibers that are held and focused are not easily separated from each other, and the spores and the like that are held in the gaps between the fibers are not easily dropped even in a severe wave state.

  The heat-fusible conjugate fiber used in the present invention can be produced using a compound spinning device according to a conventional method. That is, it can be obtained by subjecting the composite spinning to a take-up speed of 4500 m / min or less and then drawing. When the take-up speed exceeds 4500 m / min, yarn breakage is likely to occur during spinning, and since the draw ratio is low, the strength after drawing is low, making it difficult to obtain a yarn with practical physical properties. In order to manufacture with good productivity, the take-up speed is preferably set to 1000 m / min or more. For drawing, the spun yarn can be wound once and then supplied to a drawing machine, or, after spinning, it can be drawn directly after being drawn through a drawing roller.

  The yarn constituting the seaweed culture fiber material of the present invention may be composed only of the above-mentioned heat-fusible conjugate fiber, but other than the heat-fusible conjugate fiber and the heat-fusible conjugate fiber. You may be comprised from a fiber. When other fibers are included, the other fibers are fibers composed of a polylactic acid polymer having a melting point higher by 20 ° C. than the melting point of the low melting point polylactic acid polymer constituting the heat-fusible conjugate fiber. Preferably there is. Another fiber is also composed of a polylactic acid-based polymer, so that the adhesiveness with the melted or softened low-melting-point polylactic acid-based polymer is good, so that the effects of the present invention are excellent. . In order to effectively achieve the object of the present invention, the content of the heat-fusible fiber composite fiber contained in the yarn is preferably 30% by mass or more, and more preferably 50% by mass or more.

  The form of the fiber forming the yarn may be continuous fiber or short fiber, but it is preferable to use continuous fiber in consideration of strength and the like. The cross-sectional shape of the fiber is not particularly limited, and for example, a multi-leaf such as a circle, an ellipse, a polygon such as a triangle, an alphabet such as a T-shape, a Y-shape, or an H-shape, a cross shape, a 5-leaf, a 6-leaf, etc. A shape, a square, a rectangle, a rhombus, a saddle shape, a horseshoe shape, etc. can be mentioned, and these shapes may be partially changed. Moreover, you may use combining suitably the fiber of these various cross-sectional shapes.

  The form of the yarn may be a continuous fiber, a spun yarn made of short fibers, or a mixture of continuous fibers and short fibers. In addition, a twisted yarn in which a multifilament and a monofilament are twisted together, a twisted yarn in which a multifilament and a spun yarn are twisted together, a twisted yarn in which a monofilament and a spun yarn are twisted together, or monofilaments or multifilaments are twisted together. It may be a twisted yarn.

  The single yarn fineness of the fibers forming the yarn may be selected as appropriate, but the fineness of each single yarn constituting the multifilament or spun yarn is preferably 3.3 to 22 dtex, It is preferable that the fineness is 55 to 2200 dtex, and the fineness of the spun yarn is also 55 to 2200 dtex. In the case of monofilaments, the single yarn fineness is preferably 55 to 1100 dtex, from the viewpoint of convergence, durability, or netting properties when the yarn is formed by twisting monofilaments when forming a material in the form of a net, 220 to More preferred is 670 dtex. When the single yarn fineness is too large, the contact points between the fibers are relatively decreased, and in some cases, sufficient adhesive strength may not be exhibited. The fineness of the yarn formed by these fibers may be selected as appropriate, but is about 60 to 50,000 dtex.

  In the yarn which is the fiber material for seaweed cultivation of the present invention, the constituent fibers are thermally bonded via a molten or softened low melting point polylactic acid polymer. Since at least the contact point between the fibers is thermally bonded by the low melting point polylactic acid polymer, the gap between the fibers is fixed without being deformed even by an external force, and the fibers can be prevented from being broken. The retained seaweed spores are less likely to fall off. The method of thermally bonding the fibers can be performed by passing through a heat treatment apparatus set to a temperature at which only the low melting point polylactic acid polymer melts or softens. What is necessary is just to set the processing time at the time of letting it pass in the heat processing apparatus suitably considering the preset temperature of a heat processing apparatus. As the heat treatment apparatus, it is preferable to heat treat the yarn by passing through a tunnel furnace having a specific diameter. By appropriately selecting the diameter of the yarn before the heat treatment in consideration of the inner diameter of the tunnel furnace, the size of the gap between the fibers can be appropriately set. In addition, after heating the yarn, the fibers can be thermally bonded while appropriately setting the size of the gap between the fibers by passing a tube having a predetermined inner diameter (diameter equal to or less than the diameter of the yarn). it can.

  In the present invention, using the above-described fiber material for seaweed aquaculture, netting or the like is performed to obtain a seaweed aquaculture material. Moreover, the above-mentioned seaweed culture fiber material, itself, can also be used as seaweed culture material. In the present invention, the seaweed aquaculture material is in the form of nets, ropes, twisted yarns, and is used to grow spores and seeds of seaweed such as seaweed, kelp, honda, mozuku, etc. Say what you do.

  The seaweed aquaculture material of the present invention may be composed only of the above-mentioned seaweed aquaculture fiber material, but the strength, flexibility, dryness, dimensional stability, adhesion of seaweed spores, seaweed spores, Depending on the purpose such as thinning out and adjusting specific gravity, other yarns composed of one or more fibers selected from other polyester fibers, polyamide fibers, polypropylene fibers, polyethylene fibers, etc. may be used in combination. In the seaweed cultivating material of the present invention, the content of the fiber material for cultivating seaweed of the present invention may be determined as appropriate according to the place of use and the respective required characteristics, but the total mass of the yarn constituting the seaweed cultivating material It is preferable to set it as 30 mass% or more.

  When the seaweed aquaculture material of the present invention is in the form of a net, the shape of the net is not particularly limited, and can be applied to conventionally known materials such as a knot net, a knotless net, a cocoon net, and a woven net.

  Moreover, there exists the following method as another embodiment for obtaining the seaweed culture material of this invention. That is, a seaweed aquaculture material is manufactured using yarns that are bundled with a plurality of fibers that are untwisted or that have a plurality of fibers that are twisted and that contain a heat-fusible composite fiber In this method, the yarn prepared as the material constituting the material is not yet heat-treated, and the fibers are not thermally bonded. As described above, the heat-fusible conjugate fiber is composed of a high-melting polylactic acid polymer and a low-melting polylactic acid polymer having a melting point that is 20 ° C. lower than the melting point of the high-melting polylactic acid polymer, The low melting point polylactic acid polymer occupies at least a part of the fiber surface. Sea yarn algae cultivation material that takes the form of a rope or net, etc. after making it into an appropriate form such as a rope or net using a yarn that has not been heat-treated yet and whose fibers are not thermally bonded to each other Further, heat treatment is performed at a temperature at which the low melting point polylactic acid polymer is melted or softened, and at least the contact points of the fibers are melted or softened to be thermally bonded through the low melting point polylactic acid polymer. The heat treatment may be performed at a temperature at which only the low melting point polylactic acid-based polymer that is a heat bonding component is melted or softened, and the treatment time may be appropriately set according to the treatment temperature. Specific examples of the heat treatment apparatus include a method of passing through a hot air circulation apparatus and a method of heat treatment along a hot roll. In the stage of forming a material such as a net by performing heat treatment after forming a suitable shape such as a rope or a net using a yarn that is not heat-bonded yet without heat treatment, Has the advantage that it is not hard because it does not have a thermal bonding point, and is flexible and easy to handle. In addition, by applying heat treatment after forming an appropriate form such as a rope or a net, a thermal bonding point can be formed at the contact between the yarns and at the contact between the yarns at the knot point, and the mechanical strength as a whole Seaweed aquaculture material excellent in

  The fiber material for seaweed aquaculture of the present invention comprises a high-melting polylactic acid-based polymer and a low-melting-point polylactic acid-based polymer, and a yarn containing a composite fiber in which the low-melting-point polylactic acid-based polymer occupies a part of the fiber surface. The fibers constituting the yarn are thermally bonded to each other by a molten or softened low melting point polylactic acid polymer. Therefore, seaweed aquaculture materials such as nets and ropes made using this yarn (seaweed aquaculture fiber material) are difficult to move because each fiber is scattered in seawater and adheres to the gaps between the fibers. This makes it difficult for the spores of the seaweed to fall off. Therefore, the seaweed culture material using the seaweed culture fiber material of the present invention has good seaweed survival even when used in places with severe wave conditions (fast flow areas) such as outside the bay. The growth of seaweeds growing on the surface is unlikely to occur. Moreover, since the adhesion of seaweeds can be maintained until harvesting once they are settled, according to the seaweed culture fiber material and seaweed culture material of the present invention, a high yield can be realized.

It is a figure which shows an example of a melting endothermic curve.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by these Examples.

Example 1
Using a composite spinning facility, a concentric core-sheath type composite monofilament composed of two types of polylactic acid having different melting points by a conventional method (core: melting point 170 ° C., D-form / L-form (copolymerization molar ratio) = 2 / 98, relative viscosity 1.89, sheath: melting point 130 ° C., D-form / L-form (copolymerization molar ratio) = 8/92, relative viscosity 1.90, core / sheath (mass ratio) = 1/1) Spinned. The relative viscosity was measured at a sample concentration of 0.5 g / dl and a temperature of 20 degrees using an equimolar mixture of phenol and ethane tetrachloride as a solvent for the polymer. The spun monofilament is cooled in a water bath at 20 ° C. and then stretched and heat-set to a total of 5.0 times according to a conventional method and wound on a bobbin. The single filament fineness is 600 dtex and the cross-sectional shape is a core-sheath type A composite monofilament was obtained. The resulting monofilament has a high elongation (measured at 25 cm gripping distance and 30 cm / min pulling speed using an autograph DSS-500 model manufactured by Shimadzu Corporation according to the method described in JIS L-1013). 1 cN / dtex, 34%.

  The obtained 36 monofilaments were twisted, passed through a tunnel furnace at 150 ° C. and heat-sealed, and the seaweed aquaculture fiber material of Example 1 was obtained.

Comparative Example 1
In Example 1, the fiber material of Comparative Example 1 was obtained in the same manner as in Example 1 except that the heat fusion processing was not performed after twisting 36 monofilaments.

Example 2
In Example 1, only the polylactic acid (melting point 170 ° C., D-form / L-form (copolymerization molar ratio) = 2/98, relative viscosity 1.89) used for the core when obtaining the core-sheath type composite monofilament was used. The monofilament monofilament having a single yarn fineness of 600 dtex and a circular cross section was obtained.

  Twelve single-phase monofilaments obtained and 24 core-sheath type composite monofilaments obtained in Example 1 were twisted, passed through a tunnel furnace at 150 ° C., and heat-sealed. A seaweed aquaculture fiber material was obtained.

Example 3
In Example 1, to obtain a core-sheath type composite monofilament, the core part had a melting point of 175 ° C., D-form / L-form (copolymerization molar ratio) = 0.5 / 99.5, and a melting point of 175 ° C., L-form / Example D (copolymerization molar ratio) = 0.6 / 99.4, with equal mass of polylactic acid having a relative viscosity of 1.91 Thus, the seaweed aquaculture fiber material of Example 3 was obtained. The polypolylactic acid forming the core of the obtained core-sheath type composite monofilament had a crystal melting start temperature of 205 ° C. and a melting point of 225 ° C., forming a stereo complex.

  Using the seaweed aquaculture material obtained in Examples 1 to 3 and Comparative Example 1 as a seaweed aquaculture material, seeding of seaweed was carried out in the same manner as onshore seedlings of laver nets. The seeded material was immersed in seawater to which nutrient salt was added and subjected to aeration culture for 30 days. After 30 days, the material was pulled up, and the appearance of nori buds was visually confirmed. Moreover, it confirmed similarly using the twisted yarn which twisted 36 vinylon filaments (Unitika company No. 5 yarn <MF5> 560dtex) often used for nori culture as a reference material.

  The seaweed aquaculture materials of Examples 1 to 3 and Comparative Example 1 all show the same brown color by seeding the seaweed immediately after seeding the seaweed and are as good as the twisted yarn made of the vinylon filament as a reference material The seeds were attached to. After 30 days of observing the growth of nori buds, the seaweed aquaculture material of Examples 1 to 3 had a brownish brown color throughout the entire material in the same manner as the twisted yarn made of vinylon filaments as a reference material. Was raising seedlings. On the other hand, in the material of Comparative Example 1, there were few places that exhibited a brownish brown color in some places, and the laver sprouts were not formed overall.

Example 4
Concentric core-sheath type composite multifilament made of two types of polylactic acid having different melting points by a conventional method using a composite spinning facility (core: melting point 170 ° C., D-form / L-form (copolymerization molar ratio) = 2 / 98, relative viscosity 1.89, sheath: melting point 130 ° C., D-form / L-form (copolymerization molar ratio) = 8/92, relative viscosity 1.90, core / sheath (mass ratio) = 1/1) Spinned. The spun multifilament was stretched and heat-set by a total of 3.3 times according to a conventional method, and wound on a bobbin to obtain a multifilament of 1100 dtex / 140 f. The multifilament tensile strength (measured with a constant-speed extension type tester using a method described in JIS L-1013 at a grip interval of 20 cm and a tensile speed of 20 cm / min) was 4.7 cN / dtex, 32%. It was. Three of the obtained multifilaments were converged to give an S twist of 120 times / m, and three of the obtained twisted yarns were converged to give a Z twist of 30 times / m. The obtained yarn was passed through a 150 ° C. tunnel furnace for heat-sealing, and the seaweed aquaculture fiber material of Example 3 was obtained. The obtained seaweed culture fiber material was used as a seaweed culture material, and brown kelp spores were attached by a conventional method. Observation of this after standing in running water for a week revealed that the degree of brown was almost unchanged and the color did not fade, indicating that the kelp spores were less likely to fall off and were good aquaculture materials.

Comparative Example 2
In Example 4, a fiber material was obtained in the same manner as in Example 4 except that the heat fusion process through a tunnel furnace was not performed. Using the obtained fiber material, a kelp spore adhesion test was conducted in the same manner as in Example 4. After standing for 1 week in running water, the brown color was remarkably reduced, and the degree of spore loss was large. I understood.

Claims (5)

A seaweed culture fiber material used in water, wherein the fiber material is a yarn in which a plurality of fibers are untwisted or bundled and a plurality of fibers are twisted and bundled, and the yarn is at least heat A low-melting-point polylactic acid-based polymer containing a fusible conjugate fiber, wherein the heat-fusible conjugate fiber has a melting point that is at least 20 ° C. lower than the melting point of the high-melting point polylactic acid-based polymer and the high-melting point polylactic acid-based polymer. A low-melting polylactic acid polymer in which at least a part of the surface of the heat-fusible composite fiber is composed of coalesced, and the fibers constituting the yarn are melted or softened. A seaweed aquaculture fiber material characterized by being thermally bonded via The yarn is composed of a heat-fusible conjugate fiber and a fiber other than the heat-fusible conjugate fiber, and the other fiber is a fiber composed of a polylactic acid-based polymer. The fiber material for seaweed culture described. A seaweed culture material comprising at least a part of the fiber material for seaweed culture according to claim 1 or 2. The seaweed culture material according to claim 3, wherein the seaweed culture material is in the form of a rope or a net. A method for producing a seaweed aquaculture material using yarns that are bundled with a plurality of fibers that are untwisted or bundled with a plurality of fibers and that contain a heat-fusible composite fiber as the plurality of fibers The heat-fusible composite fiber is composed of a high-melting polylactic acid polymer and a low-melting polylactic acid polymer having a melting point that is 20 ° C. or more lower than the melting point of the high-melting polylactic acid polymer. The melting point polylactic acid-based polymer occupies at least a part of the fiber surface, and is made into an appropriate shape such as a rope or a net using the yarn, and then at a temperature at which the low-melting point polylactic acid-based polymer melts or softens. A method for producing a seaweed aquaculture material, characterized in that heat treatment is performed and heat bonding is performed via a low melting point polylactic acid polymer in which at least a contact between fibers is melted or softened.