Materials for promoting the growth of seaweeds, paints for manufacturing the same materials, and methods for manufacturing the same materials

Abstract

To provide a material that is not only excellent in handleability, but also capable of efficiently supplying in sea, iron which is important mineral for growth of seaweed.SOLUTION: A seaweed growth promotion material is provided with a coating layer on a base material. The coating layer includes a resin component and an iron supply agent. The iron supply agent may be a chelated matter chelated by a chelation substance. The chelation substance may be organic acid. The resin component may be one or more kinds selected from a polyester resin and a polyolefin resin. The base material may be formed into any form selected from a fiber, twist yarn, rope, woven fabric, non-woven fabric, and net. A coating for forming the coating layer includes the resin component and bivalent iron. The material is produced by a step of applying the coating to the base material and a step of drying the coating applied to the base material.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a material for promoting the growth of seaweeds, a paint for producing the material for promoting the growth of seaweeds, and a method for producing the material for promoting the growth of seaweeds.

Background Art

[0002] For the growth of useful seaweeds such as kelps and sargassums, nutrients and minerals such as nitrogen, phosphorus, and silicon are required, just like land plants such as trees and grasses. In particular, it has been pointed out that iron is essential for the growth of these seaweeds. In areas where the iron concentration in seawater is low, seaweed beds where the above-mentioned useful seaweeds grow disappear, and a phenomenon called "sabaki" occurs frequently, in which calcareous seaweeds grow significantly. The disappearance of seaweed beds and the spread of sabaki areas not only lead to a decrease in useful seaweeds but also a decrease in fishery resources because fishery animals inhabiting the seaweed beds also decrease. As a countermeasure, a technique has been proposed to restore seaweed beds by installing a structure for promoting the growth of seaweeds mainly made of concrete in sabaki areas (Patent Documents 1 and 2).

[0003] As a sea area for cultivating edible seaweeds such as nori, an inner bay where various minerals including iron flow richly from rivers is suitable. However, due to deforestation of forests that play a role in supplying nutrients to rivers, construction of dams and estuary weirs that stagnate water flow, etc., the ability of rivers as a source of nutrients including iron has decreased, and in recent years, crop failures of cultivated nori and cultivated wakame have become serious. As a means to solve this problem, a cultivation net in which iron powder is sprayed on the fibers constituting the net has been disclosed (Patent Document 3).

[0004] In Patent Documents 1 and 2, since the structure serving as an iron supply source is made of concrete, it is very heavy, and there is a problem that its handleability is poor from manufacturing to transportation and throwing it into the sea. In addition, due to the characteristics of the method of installing heavy objects, the places where the concrete structure can be installed are almost limited to the coastal areas.

[0005] The aquaculture net described in Patent Document 3 has a problem that not only does the strength of the fiber decrease by spraying iron powder, but also the iron powder easily falls off from the aquaculture net in the sea, losing the function of locally supplying iron within a short period of time.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] In view of these problems, an object of the present invention is to provide a material that is not only excellent in handleability but also can efficiently supply iron, which is an important mineral in the growth of seaweeds, in the sea.

Means for Solving the Problems

[0008] In order to solve the above problems, the material for promoting the growth of seaweeds of the present invention has a coating layer provided on a base material, the coating layer is contains a resin component and an iron supply agent while not containing water-soluble glass , the iron supply agent is iron fulvate chelated with fulvic acid, the resin component is a saturated polyester resin, the material of the base material is a polyester resin or a polyamide resin, the base material is characterized by being in any form selected from fibers, yarns, ropes, woven fabrics, non - woven fabrics, and nets.

[0013] The paint of the present invention is a paint for forming the coating layer of the above-mentioned material for promoting the growth of seaweeds, and the above-mentioned is characterized by containing a resin component and an iron supply agent

[0014] The method for producing the material for promoting the growth of seaweeds of the present invention is characterized by including a step of applying the above paint to a base material and a step of drying the paint applied to the base material.

Effect of the Invention

[0015] According to the material for promoting the growth of seaweeds of the present invention, iron can be efficiently and simply supplied in the sea, whereby the growth of seaweeds is promoted, and the recovery of seaweed beds and the increase in the yield of edible seaweeds are expected.

Mode for Carrying Out the Invention

[0016] The material for promoting the growth of seaweeds in the embodiment of the present invention has a base material and a coating layer. Among these, the coating layer contains a resin component and an iron supply agent

[0017] of the substrate Examples of the materials include resin, concrete, stone, wood, metal, etc. is suitable. Among these, resin can be preferably used from the viewpoint of handleability. The resin type is For example, polyester resin, polyolefin resin, polyamide resin, polyacetal resin, fluororesin, vinyl resin, etc. can be mentioned. In the present invention Among these, from the viewpoint of processability, polyester resin, polyamide resin is used. As the shape of the substrate, the material From the viewpoint of ease of handling during installation and the size of the surface area, fiber, twisted yarn, rope, fabric, non-woven fabric, net must be any of .

[0018] Contained in the coating layer The resin component is from seaweedsIt is preferably one that does not inhibit reproduction. This resin component may be a single type of resin or a combination of multiple types of resins. For example, polyester resin, polyolefin resin, polyamide resin, alkyd resin, acrylic resin, epoxy resin, amino resin, fluororesin, silicone resin, urethane resin, vinyl resin, cellulose resin, etc., or copolymers, mixtures, etc. containing these may be mentioned. Among these, from the viewpoint of hydrophilicity, polyester resin, urethane resin, and polyamide resin are preferable, and polyester resin is more preferable. Also, a resin hydrophilized by copolymerizing a polar component such as maleic anhydride with a polyolefin resin can also be suitably used. However, in the present invention, a saturated polyester resin is used as the resin component contained in the coating layer.

[0019] The polyester resin referred to here means a resin having an ester bond, and the monomer components include dibasic carboxylic acid, dihydric alcohol, hydroxycarboxylic acid, tribasic or higher carboxylic acid, monocarboxylic acid, tribasic or higher alcohol, monoalcohol, lactone, and oxirane. Biodegradable polyester resins such as polylactic acid, polyglycolic acid, polycaproic acid, polybutylene succinate, polybutylene succinate adipate, and 3-hydroxybutanoic acid·3-hydroxyhexanoic acid copolymer (PHBH) can also be used.

[0020] The iron supply agent contained in the coating layer will be described. Although iron is an essential element for seaweeds as a trace element, as described in paragraph 0057 of JP-A-2015-107061, when the iron concentration becomes 1 μg / L or less, seaweeds will be in an iron-deficient state, not only will their growth be stagnated, but also their color will fade.

[0021] The iron supply agent contained in the coating layer serves as a source for supplying the iron necessary for seaweeds, and is required to contain elemental iron or an iron compound. As described in paragraph 0005 of WO 2007 / 013217, it is known that iron ions easily form and precipitate ferric hydroxide or the like in the presence of water. However, if this precipitate is formed in seawater, the iron content eluted in the seawater will decrease. As a result, there is a concern that the concentration of iron in the seawater attributable to the growth of seaweeds may fall below the required amount. In order to prevent the formation of the precipitate, the iron supply agent preferably has divalent iron, which is easily absorbed by algae, chelated by a chelating substance. In the present invention, iron fulvate chelated with fulvic acid is used as the iron supply agent.

[0022] Here, the chelating substance is a substance having an action of complexing (dissolving in seawater) iron ions. is Examples thereof include organic acids, humic acids, polyphenols and the like. In the present invention, as described above, fulvic acid is used as the chelating substance.

[0023] Generally, it is known that seaweeds take in and utilize iron ions in divalent form during the growth process. From this viewpoint, the chelating substance preferably has an effect of complexing iron ions in a divalent state. Furthermore, since it is suggested in paragraph 0059 of JP 2015-107061 A that the bioavailability of iron varies depending on the chelating substance being complexed, it is more preferable that the chelating substance has a high bioavailability capable of further promoting the growth of seaweeds. From this perspective as well, in the present invention, as described above, fulvic acid is used as the chelating substance.

[0024] The content of the iron supply agent in the coating layer is preferably in the range of 0.1 to 300 parts by mass, more preferably 0.5 to 200 parts by mass, and even more preferably 1 to 100 parts by mass with respect to 100 parts by mass of the resin component. When the content of the iron supply agent is less than 0.1 part by mass with respect to 100 parts by mass of the resin component, the effect of addition is small and it is difficult to obtain the effects of the present invention. When the content of the iron supply agent exceeds 300 parts by mass, the adhesiveness and durability of the resulting coating film may decrease.

[0025] Although the mechanism of iron elution from the material for promoting the growth of seaweeds of the present invention into seawater has not been fully elucidated, it is presumed that the water absorption and hydrolysis of the resin are influential. The presumed elution mechanism will be described below. That is, when the material is immersed in seawater, the resin component contained in the coating layer absorbs a small amount of water due to the inherent properties of the resin and becomes in a swollen state. The swollen state can be considered microscopically as a state where the interval between the polymer chains of the resin component has widened, and it is considered that iron elutes into seawater by the movement of the iron supply agent from the gaps between these polymer chains. Furthermore, the water-absorbed resin component undergoes hydrolysis depending on the resin type. When hydrolysis occurs, the resin component becomes brittle from the surface of the coating layer in contact with seawater, and in some cases, a part of it falls off. As a result, the iron supply agent is exposed on the surface and iron elutes into seawater. Since the water absorption rate and hydrolyzability of the resin component are determined by the selected resin type, when it is desired to increase the elution amount, a resin type with a high water absorption rate and / or hydrolyzability can be selected, and when it is desired to reduce the elution amount and extend the elutable period, a resin type with a low water absorption rate and / or hydrolyzability can be selected. On the other hand, also with respect to the iron supply agent, it is desirable that it has high solubility in water in order to be dissolved by the small amount of water absorbed as described above and to pass through the gaps between the polymer chains in the swollen state. Also from this viewpoint, the iron supply agent is chelated with a chelating substance shall be .

[0026] The coating material of the present invention can be obtained by mixing, in an arbitrary method, solutions in which the above resin component and iron supply agent are respectively dissolved or dispersed in a liquid medium.

[0027] The liquid medium used when adjusting the coating material may be an aqueous medium (including water) or a non-aqueous medium. The aqueous medium refers to water or a water-soluble organic solvent with a solubility of 50 g / L or more in water at 20°C. Specific examples of such water-soluble organic solvents include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, cyclohexanol, etc.; ketones such as methyl ethyl ketone, methyl isobutyl ketone, ethyl butyl ketone, cyclohexanone, isophorone, etc.; ethers such as tetrahydrofuran, dioxane, etc.; esters such as ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, isobutyl acetate, sec-butyl acetate, 3-methoxybutyl acetate, methyl propionate, ethyl propionate, diethyl carbonate, dimethyl carbonate, etc.; glycol derivatives such as ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol ethyl ether acetate, propylene glycol, propylene glycol monomethyl ether, propylene glycol monobutyl ether, propylene glycol methyl ether acetate, etc.; and further, 3-methoxy-3-methylbutanol, 3-methoxybutanol, acetonitrile, dimethylformamide, dimethylacetamide, diacetone alcohol, ethyl acetoacetate, etc.

[0028] When the liquid medium is an aqueous medium, the paint becomes an aqueous paint, and in its production, the resin may be dissolved or dispersed in water for preparation. The temperature and stirring conditions during dissolution / dispersion may be arbitrary. For example, when the iron supply agent is unstable in a solvent-based system or when special consideration for environmental protection is required, the aqueous paint can be effectively used.

[0029] As a method for dissolving or dispersing the resin component and the iron supply agent in the aqueous medium, a known method can be used. When a water-soluble resin component and an iron supply agent are used, a solution can be obtained by heating, stirring, or even pressurizing in the aqueous medium. When a water-insoluble resin component and an iron supply agent are used, it is effective to use a method of dispersing them in the aqueous medium to obtain a dispersion. When dispersing using a non-volatile emulsifier, in order to maintain high performance of the water resistance of the coating film, the content of the emulsifier in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and most preferably zero with respect to the total solid content. When emulsifiers are present in the coating film, they tend to cause a decrease in the water resistance, durability, and adhesion to the substrate of the coating film.

[0030] Examples of the non-aqueous medium include hydrocarbons represented by toluene, heptane, xylene, amylbenzene, isopropylbenzene, octane, cyclohexane, cyclohexylbenzene, cyclohexene, cyclopentane, dipentene, cymene, turpentine oil, hexane, pentane, mesitylene, methylcyclohexane, etc. The above liquid medium may be used alone or as a mixture of two or more kinds.

[0031] When the liquid medium is a non-aqueous medium, the paint becomes a solvent-based paint, and in its production, the resin may be dissolved in an organic solvent for preparation. The temperature and stirring conditions during dissolution may be arbitrary. For example, when the resin cannot be dissolved or dispersed in water, when the iron supply agent is unstable in an aqueous paint, or when fast drying is required, the solvent-based paint can be effectively used.

[0032] As a method for dissolving or dispersing a resin component and an iron supplier in a non-aqueous medium, a known method can be used, and a method of dissolving the resin component and the iron supplier in a non-aqueous medium is common. Examples of the dissolving method include heating, stirring, and even pressurizing the resin component and the iron supplier in a water-insoluble solvent. By this, a solution of the resin component and the iron supplier can be obtained.

[0033] The concentration of non-volatile components such as the resin component and the iron supplier in the paint is not particularly limited as long as the paint has a viscosity that can be applied to the substrate. Usually, in order to obtain an appropriate viscosity for coating, the concentration of non-volatile components is preferably 60% by mass or less, and more preferably 30 - 50% by mass.

[0034] In addition to the resin component and the iron supplier, additives such as cross-linking agents, inorganic particles, pigments, and dyes may be added to the paint as long as the object of the present invention is not impaired.

[0035] As the cross-linking agent, a self-crosslinkable cross-linking agent, a cross-linking agent having a plurality of functional groups reactive with a carboxyl group in the molecule, a metal complex having a polyvalent coordination site, etc. can be used. Specifically, oxazoline-based cross-linking agents, isocyanate-based cross-linking agents (including blocked types), amine-based cross-linking agents, carbodiimide-based cross-linking agents, melamine-based cross-linking agents, urea-based cross-linking agents, epoxy-based cross-linking agents, zirconium salt compounds, silane coupling agents, organic peroxides, etc. can be mentioned. Among them, a cross-linking agent having a plurality of functional groups reactive with a carboxyl group in the molecule is more preferable. Examples of such cross-linking agents include oxazoline-based cross-linking agents, carbodiimide-based cross-linking agents, epoxy-based cross-linking agents, isocyanate-based cross-linking agents, amine-based cross-linking agents, melamine-based cross-linking agents, etc. These may be used in combination of a plurality. By adding a cross-linking agent, an increase in the coating film strength, an improvement in the adhesion to the substrate, an improvement in water resistance, insolubilization of the coating film, etc. can be achieved. The addition amount of the cross-linking agent may be appropriately selected in consideration of both the effects of the present invention and the effects of the addition purpose, but is preferably 1 - 50 parts by mass, and more preferably 1 - 30 parts by mass with respect to 100 parts by mass of the resin component.

[0036] Examples of the inorganic particles include metal oxides such as magnesium oxide, zinc oxide, and tin oxide; inorganic particles such as calcium carbonate and silica; and layered inorganic compounds such as vermiculite, montmorillonite, hectorite, hydrotalcite, and synthetic mica. From the perspective of the liquid stability of the paint, the average particle diameter of these inorganic particles is preferably 0.005 to 10 μm, more preferably 0.005 to 5 μm. The addition amount is appropriately set according to the purpose, but usually, 0.01 to 30 parts by mass is preferably added per 100 parts by mass of the resin component. Note that a plurality of inorganic particles may be mixed and used.

[0037] Examples of the pigments and dyes include titanium oxide, zinc white, carbon black, etc., and any of disperse dyes, acid dyes, cationic dyes, reactive dyes, etc. can be used. The addition amount is appropriately set according to the purpose, but usually, 0.01 to 30 parts by mass is preferably added per 100 parts by mass of the resin component.

[0038] Various agents such as a leveling agent, an antifoaming agent, an anti-wicking agent, a pigment dispersant, an ultraviolet absorber, a thickener, a weathering agent, and a flame retardant can also be added to the paint of the present invention as required.

[0039] The above additives may be used alone or in combination of two or more.

[0040] As a method for applying the paint of the present invention, there is no particular limitation, and any conventionally used coating method may be selected according to the type of the substrate. Examples of the coating method include roll coating, spray coating, dip coating, brush painting, and the like. Further, if necessary, it is preferable to provide a drying step for removing the liquid medium in the paint after coating. The drying method and drying conditions are not particularly limited and can be appropriately set according to the thickness of the coating film and the like. In order to dry efficiently, it is preferable to perform heat drying. The drying temperature is preferably 40 to 250°C, more preferably 60 to 200°C. Also, from the viewpoint of productivity and the like, the drying time is preferably 5 to 1200 seconds, more preferably 10 to 900 seconds, and even more preferably 20 to 600 seconds. Further, heat treatment may be performed in any step after drying.

[0041] For example, when dip coating is selected, after immersing the substrate in a paint containing a resin component and an iron supply agent and then pulling it up, and heating and drying it in a hot air dryer under the conditions of 100°C for 120 seconds, the material for promoting the growth of seaweeds in the present invention can be obtained. Also, when a fiber product is used as the substrate, as the time point for forming the coating layer on the substrate, there are the time point when the fiber is produced, the time point when the fiber is twisted into a yarn, the time point when the fiber or yarn is processed such as knitted or woven, etc., and these may be appropriately selected according to the usage of the material.

[0042] The thickness of the coating layer in the present invention may be appropriately set according to the purpose. For example, as the thickness of the coating film after drying, 0.1 to 500 μm is preferable, 0.5 to 200 μm is more preferable, and 1 to 100 μm is even more preferable. When the thickness of the coating film is less than 0.1 μm, the effect of the present invention is small, and when it exceeds 500 μm, the effect becomes saturated, which is economically disadvantageous.

Examples

[0043] (Adjustment of paint) A saturated copolymerized polyester resin (trade name: Elitel, product number: UE-3600, a resin that exhibits adhesiveness to polyethylene terephthalate resin) manufactured by Unitika Ltd. was prepared. Also, the following were prepared as iron suppliers. · Iron fulvate (manufactured by P.I.C. Bio, dried product of Canadian fulvate, iron content in the dried product: 5.23% by mass) · Iron(II) oxide (manufactured by Terada Yakuen Kogyo Co., Ltd., containing 60% iron oxide, black powder, iron content: 0.466 g / g)

[0044] The above-mentioned saturated copolymerized polyester resin (UE-3600) was dissolved in a mixed solution of toluene / methyl ethyl ketone = 1 / 1 (mass ratio) so that the solid content became 30% by mass. Then, an iron supplier was mixed into the solution so that the ratio of the iron supplier to the resin was as shown in Table 1 below, and the mixture was stirred to prepare the paints of Production Examples 1 to 5.

[0045]

Table 1

[0046] (Preparation of Mesh and Sheet) A mesh as a base material was manufactured as follows. That is, polyethylene terephthalate with a melting point of 260°C was prepared, and long fibers with a fineness of 8.7 decitex were produced. Next, 192 of these long fibers were converged to obtain a polyester multifilament yarn of 1670 decitex / 192. Eight of these multifilament yarns were made into a cord and applied to a net-making machine to produce a 15 cm square knotted net. Next, this knotted net was heat-treated in an atmosphere of 150°C for 3 minutes while applying tension in the width direction with a pin tenter type heat treatment device, and then a cooling treatment was performed to obtain the target net fabric.

[0047] A sheet as a base material was manufactured as follows. That is, a polyester resin (polyethylene terephthalate, relative viscosity: 1.62, intrinsic viscosity: 1.2, melting point 255°C) was pressed with a press machine at 210°C × 0.1 MPa × 1 minute to obtain a sheet of 5.5 × 5.5 × 0.1 cm.

[0048] (Coating method) Regarding the above-mentioned net, the net was immersed in the paint, and after lifting the net from the paint, the excess paint was dropped, and further dried at 100 °C for 5 minutes with a hot air dryer.

[0049] Regarding the sheet, the paint was applied to both sides of the sheet with a wire bar so that the coating amount was 10 g / m 2 for each side, and then dried at 100 °C for 2 minutes for each side with a hot air dryer.

[0050] (Evaluation) The elution status of iron was tested. That is, the net or sheet with the coating layer formed as a sample was placed in a petri dish and immersed in 70 g of artificial seawater. After one week, the sample was taken out of the petri dish, and the elution amount (ppm) of iron from the sample was measured using an ICP mass spectrometer to conduct the evaluation.

[0051] (Example 1) The net as the base material was immersed in the paint of Production Example 1 to form a coating layer. The mass difference before and after the application of the paint, that is, the mass of the coating layer, was 1.06 g. As shown in Table 1, since the paint of Production Example 1 had a resin component / divalent iron supply agent (mass ratio) of 100 / 20, the mass of the divalent iron supply agent contained in this paint was 1.06×20 / (100 + 20) = 0.177 g. Since this divalent iron supply agent, that is, iron fulvate, had an iron content of 5.23 mass% as described above, ultimately, the mass of iron contained in this divalent iron supply agent was 0.177×0.0523 = 0.009 g.

[0052] The evaluation results for Example 1 are shown in Table 2.

[0053]

Table 2

[0054] ( Reference Example 1 ) A coating layer was formed using a sheet as the base material and the paint of Production Example 2. Since the sheet was 5.5 × 5.5 cm in size as described above, when converted to "m 2 ", it was 5.5 × 5.5 / 10000 (m 2 ). Since the paint was applied to both sides of this sheet at 10 g / m 2 for each side, the mass of the coating layer was 5.5 × 5.5 / 10000 × 10 × 2 = 0.061 g. Also, when calculated by the same method as in Example 1, the mass of the divalent iron supply agent contained in this paint was 0.030 g, and the mass of iron contained in this divalent iron supply agent was 0.030 × 0.0523 = 0.002 g. Reference Example 1 The evaluation results for

[0055] ( Reference Example 2 ) A coating layer was formed using a sheet as the base material and the paint of Production Example 3. As a result, similarly, the mass of the coating layer was 0.061 g, the mass of the divalent iron supply agent contained in the paint was 0.006 g, and the mass of iron contained in this divalent iron supply agent was 0.003 g. Reference Example 2 The evaluation results for

[0056] ( Reference Example 3 ) A coating layer was formed using a sheet as the base material and the paint of Production Example 4. As a result, similarly, the mass of the coating layer was 0.061 g, the mass of the divalent iron supply agent contained in the paint was 0.0030 g, and the mass of iron contained in this divalent iron supply agent was 0.014 g. Reference Example 3 The evaluation results for

[0057] (Comparative Example 1) A coating layer was formed using a net as the base material and the paint of Production Example 5 which contains a resin component but does not contain a divalent iron supply agent. In this Comparative Example 1, naturally, both the mass of the divalent iron supply agent contained in the paint and the mass of iron contained in this divalent iron supply agent were 0 g. The evaluation results for Comparative Example 1 are shown in Table 2.

[0058] (Comparative Example 2) A coating layer was formed using a sheet as the base material and the paint of Production Example 5. Also in this Comparative Example 2, as in Comparative Example 1, both the mass of the divalent iron supply agent contained in the paint and the mass of iron contained in this divalent iron supply agent were 0 g. Table 2 shows the evaluation results for Comparative Example 2.

[0059] As is clear from Table 2, from the Example 1 materials of the present invention, it was confirmed that iron was eluted into artificial seawater after one week had passed. Therefore, it was considered to function effectively in promoting the growth of seaweeds in seawater.

Claims

1. A coating layer is provided on a substrate, the coating layer contains a resin component and an iron supply agent and does not contain a water-soluble glass, the iron supply agent is iron fulvate chelated with fulvic acid, the resin component is a saturated polyester resin, the material of the substrate is a polyester resin or a polyamide resin, the substrate is in any form selected from fiber, yarn, rope, fabric, non-woven fabric, and net, and is a material for promoting the growth of seaweeds.

2. A paint for forming the coating layer of the material for promoting the growth of seaweeds according to Claim 1, the paint containing the resin component and the iron supply agent according to Claim 1.

3. A method for manufacturing the material for promoting the growth of seaweeds according to Claim 1, the method including a step of applying the paint according to Claim 2 to a substrate and a step of drying the paint applied to the substrate.

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