Liquid mulch formation composition

Abstract

The present invention provides a liquid mulch-forming composition that can form a solidified layer with thickness, excellent strength, and water permeability. [Solution] The liquid multi-forming composition of the present invention contains (A) a resin and (B) a surfactant, wherein the mass ratio of (B) surfactant to (A) resin is 0.2 or more.

Description

Technical Field

[0001] The present invention relates to a composition for forming a liquid multi.

Background Art

[0002] The seed spraying method, which is one of the greening methods, is excellent for construction over a wide area and is the simplest and most economical method among the slope greening methods that can also be applied to slopes with a high altitude or gradient. However, it has poor erosion prevention effect until initial growth and may be eroded by rain on the slope, so attention is required to the soil geology of the construction site and the construction period. In particular, coastal areas are sandy and prone to drying, so in addition to being unsuitable for greening, they are easily eroded by rain and wind, so it has been desired to prevent erosion of the slope and protect it by greening from the perspective of landscape. Conventionally, in order to solve these problems, synthetic resin has been used as a bonding material in the seed spraying method, but the problem has been to form a strong solidified layer that prevents seeds from being washed away until plants grow in terms of erosion prevention.

[0003] In soil storage facilities and construction sites, in order to prevent the scattering of the soil surface by wind and the outflow of soil by rain, soil is covered immediately at the end of daily work or covered with a sheet. However, the resin film used has problems such as the need for a recovery operation after use and the scattering of the deteriorated resin film.

[0004] Liquid mulch-forming compositions have been proposed as a technology to prevent soil scattering and erosion (Patent Documents 1-4). These compositions, consisting of resin emulsions, prevent soil scattering and erosion by spraying them, and further stabilize the soil with plants that germinate and grow by mixing seeds into the liquid mulch-forming composition and spraying it. Recently, biodegradable liquid mulch-forming compositions have also been proposed from an environmental perspective. However, conventional liquid mulch-forming compositions could only form a thin film. In particular, when exposed to large amounts of rainwater such as torrential downpours, the thin film breaks down, and sufficient erosion prevention effect cannot be obtained. Therefore, for erosion prevention applications, it is necessary to cover the seeds with sheets or the like to prevent them from being washed away until the plants sprout, which is inefficient and difficult to implement in large-scale construction projects. In order to prevent damage from natural factors such as exposure to large amounts of rainwater, there has been a need for a technology to form a solidified layer that is thick, strong, and also permeable, i.e., has good drainage.

[0005] The applicant has proposed a soil modifier that is excellent in improving plant growth, film formation, soil aggregation, and water retention (Patent Document 5). This technology improves the properties of the film by incorporating a larger amount of nonionic surfactant into the resin than conventional methods, and studies have been conducted on the application of a base material to soil, in which the soil modifier is added and mixed with a soil-based material. However, the studies at this stage have assumed that the aforementioned sheets, etc., will be used to cover seeds to prevent them from being washed away, and have focused on the film properties of the film itself formed by the soil modifier and the modification of the soil surface, without considering the formation of a thick solidified layer by the soil itself into which the components have penetrated. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2006-087324 [Patent Document 2] Japanese Patent Publication No. 2004-313048 [Patent Document 3] Japanese Patent Publication No. 2001-045879 [Patent Document 4] Japanese Patent Publication No. 2000-004687 [Patent Document 5] Patent No. 7367252 [Overview of the project] [Problems that the invention aims to solve]

[0007] This invention has been made in view of the above circumstances, and aims to provide a liquid multi-forming composition that can form a thick solidified layer. [Means for solving the problem]

[0008] Conventionally, resins have been dispersed with surfactants to produce aqueous dispersions of resins. However, the amount of surfactant is usually determined based on the need for stable dispersion of resin particles, and it was thought that increasing it beyond what is necessary would break down the emulsion. Therefore, the mass ratio of surfactant was not increased beyond what is necessary. However, in order to solve the above problem, the inventors conducted diligent research and unexpectedly discovered that increasing the mass ratio of surfactant to resin beyond a certain range allowed for the formation of a thicker solidified layer compared to conventional methods, making it suitable for use as a liquid multi-forming composition. This led to the completion of the present invention.

[0009] In other words, the liquid multi-forming composition of the present invention contains (A) a resin and (B) a surfactant, and is characterized in that the mass ratio of (B) surfactant to (A) resin is 0.2 or more. [Effects of the Invention]

[0010] The liquid mulch-forming composition of the present invention promotes penetration into soil and other materials, enabling the formation of a thicker solidified layer compared to conventional methods. In particular, it can form a solidified layer that is thick, strong, and has excellent water permeability and drainage. [Brief explanation of the drawing]

[0011] [Figure 1] These are photographs of the state after spraying the liquid mulch-forming compositions of Example 1 and Comparative Example 3 onto a vegetation substrate and allowing them to penetrate, as well as the solidified layer removed from it. [Modes for carrying out the invention]

[0012] The following describes specific embodiments for carrying out the present invention.

[0013] The liquid multi-forming composition of the present invention contains (A) a resin and (B) a surfactant. <(A) Resin> In the liquid mulch-forming composition of the present invention, (A) resin is the main component for forming a solidified layer, particularly a thick solidified layer, on the surface of soil or the like by spraying the liquid mulch-forming composition onto soil or the like.

[0014] (A) The resin is not particularly limited, but examples include synthetic resins and biodegradable resins. Among these, biodegradable resins are preferred because they decompose in the environment and do not require recovery work.

[0015] The synthetic resin is not particularly limited, but examples include thermoplastic resins such as vinyl acetate resin, polyolefin resin, polyester resin, polyether resin, polythioether resin, polysulfone resin, polycarbonate resin, polyamide resin, and fluororesin; and thermosetting resins such as phenolic resin, urea resin, urethane resin, melamine resin, guanamine resin, epoxy resin, acrylic resin, and silicone resin. These may be used individually or in combination of two or more.

[0016] The biodegradable resin is not particularly limited, but examples include polylactic acid, copolymers of lactic acid and other hydroxycarboxylic acids, polycaprolactone, copolymers of caprolactone and other hydroxycarboxylic acids, polyhydroxybutyrate, copolymers of polyhydroxybutyrate and other hydroxycarboxylic acids, and dibasic acid polyesters such as polybutylene succinate, polybutylene succinate adipate, polyethylene succinate, and polybutylene adipate. These may be used individually or in combination of two or more.

[0017] Among the biodegradable resins mentioned above, the other hydroxycarboxylic acids in the copolymer are not particularly limited, but include, for example, glycolic acid, 2-hydroxybutanoic acid, 2-hydroxypentanoic acid, 2-hydroxyhexanoic acid, 2-hydroxyheptanoic acid, 2-hydroxyoctanoic acid, 2-hydroxy-2-methylpropanoic acid, 2-hydroxy-2-methylbutanoic acid, 2-hydroxy-2-ethylbutanoic acid, 2-hydroxy-2-methylpentanoic acid, 2-hydroxy-2-ethylpentanoic acid, 2-hydroxy-2-propylpentanoic acid, 2-hydroxy-2-butylpentanoic acid, 2-hydroxy Examples include roxy-2-methylhexanoic acid, 2-hydroxy-2-ethylhexanoic acid, 2-hydroxy-2-propylhexanoic acid, 2-hydroxy-2-butylhexanoic acid, 2-hydroxy-2-pentylhexanoic acid, 2-hydroxy-2-methylheptanoic acid, 2-hydroxy-2-ethylheptanoic acid, 2-hydroxy-2-propylheptanoic acid, 2-hydroxy-2-butylheptanoic acid, 2-hydroxy-2-methyloctanoic acid, 3-hydroxypropanoic acid, 4-hydroxybutanoic acid, 5-hydroxypentanoic acid, 6-hydroxyhexanoic acid, and 7-hydroxyheptanoic acid. These may be used individually or in combination of two or more. Lactic acid and hydroxycarboxylic acid may take the form of D-isomer, L-isomer, D / L-isomer, etc., but any form is acceptable and is not particularly limited. When polylactic acid is used, the D-lactic acid content is preferably 1 to 30 mol%, and more preferably 5 to 20 mol%.

[0018] Among these, polylactic acid and polycaprolactone are preferable, and polycaprolactone is more preferable because they are suitable for sufficiently obtaining the effects of the present invention.

[0019] The molecular weight of the biodegradable resin is not particularly limited, but when shown in descending order of preference, it is 1,000 to 1,000,000, 10,000 to 800,000, and 50,000 to 600,000. Among them, the weight average molecular weight of polylactic acid is preferably 50,000 to 1,000,000, more preferably 100,000 to 800,000, and even more preferably 200,000 to 600,000 from the viewpoint of being suitable for sufficiently obtaining the effects of the present invention. The weight average molecular weight of polycaprolactone is preferably 1,000 to 200,000, more preferably 10,000 to 150,000, and even more preferably 50,000 to 100,000 from the viewpoint of being suitable for sufficiently obtaining the effects of the present invention. The weight average molecular weight (Mw) of polylactic acid and polycaprolactone can be determined by, for example, gel permeation chromatography (GPC) by comparing with a standard substance with a known molecular weight according to the method described in the Examples section below.

[0020] The liquid multi-forming composition of the present invention preferably has a low minimum film-forming temperature (MFT) from the viewpoint of forming a film with high strength. Considering forming a film at the temperature in the atmosphere, the minimum film-forming temperature of the liquid multi-forming composition is preferably 50°C or lower, and more preferably 40°C or lower. When containing polylactic acid or the like having a high minimum film-forming temperature as the resin, it is preferable to use a plasticizer in combination. Polylactic acid has a minimum film-forming temperature of, for example, 160°C or higher, but it can be lowered to 100°C or lower by blending a plasticizer.

[0021] <(B) Surfactant> In the liquid multi-forming composition of the present invention, the (B) surfactant is a main component for dispersing the (A) resin in the (C) aqueous solvent. It is also a main component for promoting the penetration of the liquid multi-forming composition into soil or the like and forming a solidified layer having thickness and strength.

[0022] In this invention, the terms (A) resin and (B) surfactant are used with their usual meanings in mind. However, a person skilled in the art can clearly select which category a substance that is both a resin and a surfactant belongs to based on its function, thereby clarifying the range of mass ratios of the two specified in this invention. In this invention, the terms (A) resin and (B) surfactant are distinguished from the common technical knowledge for solidifying soil in the technical fields related to this invention, particularly in promoting growth and preventing soil scattering and erosion in greening work. (A) Resins may be particularly hydrophobic (water-insoluble) in order to adhere soil particles together without dissolving in the soil and to form an insoluble film. In this invention, among substances that are resins in the usual sense, those that have surfactant properties are (B) surfactants.

[0023] The liquid mulch-forming composition of the present invention has a mass ratio of (B) surfactant to (A) resin of 0.2 or higher. Among these, the preferred ratios are, in order: 0.4 or higher, 0.6 or higher, 0.8 or higher, 1.0 or higher, 1.5 or higher, 2.0 or higher, 2.5 or higher, 3.0 or higher, 3.5 or higher, 4.0 or higher, 4.5 or higher, 5.0 or higher, 5.5 or higher, 6.0 or higher, 6.5 or higher, and 7.0 or higher. When the mass ratio is within this range, it is suitable for forming a solidified layer that is thick, strong, and permeable. It also leads to soil aggregation and improved water retention. These contribute to the formation of a strong solidified layer and improved plant growth. If there is too much (A) resin, the resin particles cannot be dispersed stably, and the formed film will also be uneven. It was previously thought that increasing the amount of surfactant, especially nonionic surfactant, too much could break down the emulsification and that excessive water permeability would prevent the formation of a film on the soil surface. However, by using surfactant (B) in a mass ratio of 0.2 or more to resin (A), and in particular by using surfactant (B1) with a molecular weight greater than 5000 and surfactant (B2) with a molecular weight of 5000 or less as surfactant (B), it is possible to form a uniform and thick film on the soil surface without breaking down the emulsification. The upper limit of this mass ratio is not particularly limited, but in order of preference, suitable for obtaining the effects of the present invention by ensuring fluidity that is easy to work with and avoiding excessive foaming during use, the following are preferred: 150 or less, 100 or less, 90 or less, 80 or less, 70 or less, 60 or less, 50 or less, 40 or less, 30 or less, 20 or less, and 10 or less.

[0024] Covering the soil surface on which crops and plants grow is called mulching, and it can provide effects such as protecting seeds, regulating soil temperature, suppressing weeds, preventing drying, and preventing diseases. While mulch is a film that is simply covered with a sheet, liquid mulch, as in the present invention, is a solidified layer formed by spraying a liquid composition and allowing it to penetrate the soil. Since the composition for forming liquid mulch is a composition that makes this possible, it must be a composition that penetrates the soil. Soil modifiers are used in vegetation work. Examples of soil modifiers include bonding agents for seed scattering, topsoil spraying, and vegetation (thick layer) base material spraying. Seed scattering is a method of scattering seeds, fertilizers, curing materials, bonding agents, etc., using a spraying machine such as a pump, while topsoil spraying and vegetation base material spraying are methods of mixing topsoil and vegetation base material and spraying them, respectively. This bonding agent is used by adding and mixing a small amount of it, along with fertilizers, etc., to the main material such as vegetation base material or topsoil. In contrast, among soil modifiers, liquid mulch-forming compositions mainly consist of components that penetrate the soil and form a solidified layer.

[0025] (B) The surfactant preferably contains (B1) a surfactant with a molecular weight greater than 5000 or (B2) a surfactant with a molecular weight of 5000 or less. Among these, (B) the surfactant preferably contains both (B1) a surfactant with a molecular weight greater than 5000 and (B2) a surfactant with a molecular weight of 5000 or less.

[0026] <(B1) Surfactants with a molecular weight exceeding 5000> In the liquid multi-forming composition of the present invention, (B1) a surfactant having a molecular weight greater than 5000 is a component for dispersing (A) the resin in (C) an aqueous solvent. That is, it stably disperses the resin particles in the liquid multi-forming composition of the present invention, which is an aqueous dispersion of resin, in the solvent. (B1) A surfactant having a molecular weight greater than 5000 can contribute to the formation of a solidified layer with thickness and strength, either as an auxiliary component of (B2) a surfactant having a molecular weight of 5000 or less, or as (B1) a surfactant having a molecular weight greater than 5000 alone.

[0027] (B1) The surfactant has a molecular weight of over 5000. By using the (B1) surfactant, a solidified layer with thickness and strength can be formed by dispersing the (A) resin in the (C) aqueous solvent in the form of fine resin particles. The molecular weights of the (B1) surfactant, in order of preference, are 10,000 or more, 50,000 or more, 60,000 or more, 70,000 or more, 80,000 or more, 90,000 or more, and 100,000 or more. The upper limit of the molecular weight is not particularly limited, but is preferably 300,000 or less.

[0028] (B1) The surfactant is not particularly limited, but examples include nonionic polymers, anionic polymers, cationic polymers, and amphoteric polymers.

[0029] Examples of nonionic polymers include polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, maleated polybutene, maleated polybutadiene, polymethyl vinyl ether, and acrylic acid / alkyl methacrylate copolymers.

[0030] Examples of anionic polymers include polyacrylates, polymethacrylates, acrylate / acrylamide copolymers, and polystyrene sulfonates.

[0031] Examples of cationic polymers include carboxymethylcellulose and cationized cellulose.

[0032] (B1) The molecular weight of a surfactant is determined by considering the average molecular weight that has been conventionally used, depending on its type. Typical examples include the weight-average molecular weight (Mw) or, in the case of polyvinyl alcohol, the average molecular weight based on the viscosity-average degree of polymerization. The weight-average molecular weight (Mw) can be determined, for example, by comparing it with a standard substance of known molecular weight using gel permeation chromatography (GPC).

[0033] Among the surfactants (B1) described above, nonionic polymers are preferred, and polyvinyl alcohol is more preferred, as they are suitable for obtaining the effects of the present invention.

[0034] The polyvinyl alcohol is not particularly limited, but for example, unmodified polyvinyl alcohol, special polyvinyl alcohol with a branched structure, and modified polyvinyl alcohol can be used. The modified polyvinyl alcohol is not particularly limited, but for example, ethylene-modified polyvinyl alcohol, carbonyl-modified polyvinyl alcohol, carboxyl-modified polyvinyl alcohol, alkyl ether-modified polyvinyl alcohol, acetoacetyl-modified polyvinyl alcohol, acetamide-modified polyvinyl alcohol, diacetone group-modified polyvinyl alcohol, acrylonitrile-modified polyvinyl alcohol, silicone-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, and the like can be used.

[0035] The degree of saponification of polyvinyl alcohol is not particularly limited, but it is preferably 98% or less, more preferably 90% or less, as it is suitable for obtaining the effects of the present invention. Furthermore, it is preferably 70% or more, and more preferably 75% or more.

[0036] The average molecular weight of polyvinyl alcohol can be calculated from the viscosity-average degree of polymerization, the degree of saponification, and the molecular weights of vinyl acetate units and vinyl alcohol units. The degree of polymerization of polyvinyl alcohol can be calculated from the intrinsic viscosity [η] (unit: liters / g) measured in water at 30°C after resaponification of polyvinyl alcohol with sodium hydroxide, as described in JIS K 6726, based on the following formula. Viscosity average degree of polymerization = ([η]×10000 / 8.29) (1 / 0.62) This viscosity-average degree of polymerization is converted to an average molecular weight by converting the molecular weight of vinyl acetate units and vinyl alcohol units according to the proportion of saponification. In the case of modified polyvinyl alcohol, the same calculation is performed from the viscosity-average degree of polymerization as described above.

[0037] In the liquid mulch-forming composition of the present invention, the mass ratio of (B1) surfactant having a molecular weight of more than 5000 to (A) resin is not particularly limited, but in order of preference, it is 0.0001 or more, 0.0005 or more, 0.001 or more, 0.005 or more, 0.01 or more, 0.05 or more, 0.01 or more, 0.05 or more, 0.1 or more, and 0.5 or more. When the mass ratio is within this range, the dispersibility of (A) resin is improved. When the particle size of the resin particles is fine, it is effective in bonding between fine soil particles, leading to soil aggregation and improved water retention. These contribute to the formation of a strong solidified layer and improved plant growth. The upper limit of the mass ratio is not particularly limited, but in order of preference, it is 50 or less, 40 or less, 30 or less, 20 or less, and 10 or less, which are suitable for obtaining the effects of the present invention.

[0038] <(B2) Surfactants with a molecular weight of 5000 or less> In the liquid mulch-forming composition of the present invention, (B2) a surfactant with a molecular weight of 5000 or less is a component that promotes the penetration of the liquid mulch-forming composition into soil, etc., and forms a solidified layer with thickness and strength. (B2) A surfactant with a molecular weight of 5000 or less can contribute to the action of dispersing (A) the resin in (C) an aqueous solvent, that is, the action of stably dispersing the resin particles in the liquid mulch-forming composition of the present invention, which is an aqueous dispersion of resin, in the solvent, either as an auxiliary component of (B1) a surfactant with a molecular weight of more than 5000, or by itself as (B2) a surfactant with a molecular weight of 5000 or less.

[0039] (B2) The surfactant is preferably one that has water permeability. (B2) The molecular weights of the surfactants are, in order of preference, 4500 or less, 4000 or less, and 3500 or less.

[0040] (B2) The surfactant is not particularly limited, but examples include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Among these, nonionic surfactants and anionic surfactants are preferred because they are suitable for obtaining the effects of the present invention.

[0041] Nonionic surfactants are not particularly limited, but examples include polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polypropylene glycol ethylene oxide adducts; polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether; polyoxyethylene alkylphenol ethers such as polyoxyethylene nonylphenyl ether; polyoxyalkylene fatty acid esters such as polyoxyethylene fatty acid esters; polyoxyalkylene sorbitan fatty acid esters such as sorbitan fatty acid esters and polyoxyethylene sorbitan fatty acid esters; polyoxyalkylene glycerin fatty acid esters such as glycerin fatty acid esters and polyoxyethylene glycerin fatty acid esters; and polyoxyalkylene polyglycerin fatty acid esters such as polyglycerin fatty acid esters and polyoxyethylene polyglycerin fatty acid esters. These may be used individually or in combination of two or more.

[0042] The anionic surfactant is not particularly limited, but for example, anionic surfactants such as phosphate ester salts, sulfonates, sulfates, and carboxylates can be used. These may be used individually or in combination of two or more.

[0043] Examples of phosphate ester salt type anionic surfactants include alkyl phosphates, polyoxyalkylene alkyl ether phosphates, alkylaryl ether phosphates, and fatty acid amide ether phosphates.

[0044] Examples of sulfonate-type anionic surfactants include alkanesulfonates, α-olefin sulfonates, internal olefin sulfonates, α-sulfo fatty acid methyl ester salts, acyl isethionates, alkyl glycidyl ether sulfonates, alkyl sulfosuccinates, polyoxyalkylene alkyl sulfosuccinates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, N-acyl methyl taurate salts, formalin condensate sulfonates, paraffin sulfonates, alkylamide sulfonates, alkenylamide sulfonates, alkyl glyceryl ether sulfonates, and alkylaryl ether sulfonates.

[0045] Examples of sulfate ester type anionic surfactants include alkyl sulfates, alkenyl sulfates, alkyl ether sulfates, alkenyl ether sulfates, polyoxyalkylene alkyl ether sulfates, alkylaryl ether sulfates, fatty acid alkanolamide sulfates, fatty acid monoglyceride sulfates, polyoxyalkylene aliphatic amide ether sulfates, alkylglyceryl ether sulfates, and sulfated fatty acid alkyl esters.

[0046] Examples of carboxylate-type anionic surfactants include fatty acid soaps, alkyl ether carboxylates, alkylene alkyl ether carboxylates, fatty acid amide ether carboxylates, acyl lactates, N-acyl glutamates, N-acyl alanines, N-acyl sarcosines, N-acyl-ω-amino acid salts, alkyl sulfoacetates, alkenyl sulfoacetates, alkenyl succinates, rosinates, naphthenates, and the like.

[0047] The salts that constitute anionic surfactants are not particularly limited, but examples include alkali metal salts, amine salts, and ammonium salts. Examples of alkali metal salts include sodium salts and potassium salts. Examples of amine salts include salts derived from amine compounds.

[0048] Cationic surfactants are not particularly limited, but examples include alkylamine salts, quaternary ammonium salts, alkylpyridinium salts, fatty acid triethanolamine monoester salts, alkylpolyoxyethyleneamines, and the like.

[0049] In the liquid mulch-forming composition of the present invention, the mass ratio of (B2) surfactant with a molecular weight of 5000 or less to (A) resin is not particularly limited, but in order of preference, it is 0.001 or more, 0.005 or more, 0.01 or more, 0.05 or more, 0.1 or more, 0.5 or more, and 1.0 or more. When the mass ratio is within this range, it is suitable for promoting the penetration of the liquid mulch-forming composition into soil, etc., and forming a solidified layer that is thick, strong, and permeable. The upper limit of the mass ratio is not particularly limited, but in order of preference, it is suitable for obtaining the effects of the present invention, and is 150 or less, 100 or less, 90 or less, 80 or less, 70 or less, 60 or less, 50 or less, 40 or less, 30 or less, 20 or less, and 10 or less.

[0050] <(C) Aqueous solvent> The liquid multi-forming composition of the present invention preferably contains (C) an aqueous solvent in addition to (A) a resin and (B) a surfactant. In the liquid multi-forming composition of the present invention, (C) the aqueous solvent is a medium for dispersing (A) the resin as resin particles. The (C) aqueous solvent is not particularly limited, but examples include water, or a mixed solvent of water and an organic solvent that is compatible with water. In the case of a mixed solvent, the ratio of water is not particularly limited, but is preferably 90% by mass or more, and more preferably 95% by mass or more, based on the total amount of the mixed solvent. In the mixed solvent, the organic solvent is not particularly limited, but examples include monohydric alcohols and polyhydric alcohols. Examples of monohydric alcohols include methanol, ethanol, isopropyl alcohol (IPA), n-propyl alcohol, butanol, and 3-methoxy-3-methyl-1-butanol, and examples of polyhydric alcohols include glycerin and butylene glycol.

[0051] <Aqueous resin dispersion> The liquid mulch-forming composition of the present invention is preferably a resin aqueous dispersion in which (A) resin is dispersed as resin particles in (C) an aqueous solvent. The solid content of the liquid mulch-forming composition of the present invention is not particularly limited, but it is preferable to have a low concentration from the viewpoint of promoting the penetration of the liquid mulch-forming composition into soil, etc., and forming a solidified layer that is thick, strong, and permeable. The solid content, in order of more preferable based on the total amount of the liquid mulch-forming composition, is 20% by mass or less, 10% by mass or less, less than 8% by mass, 5% by mass or less, and 3% by mass or less. Here, the solid content is the solid content immediately before use by spraying, etc., and is the percentage of mass obtained by subtracting the amount of water or other aqueous solvent from the total amount of the liquid mulch-forming composition. When vegetation materials such as seeds or soil are added to the liquid mulch-forming composition and sprayed, etc., these are excluded from the solid content. Furthermore, the lower limit of the solid content, in order of preference from the standpoint of being suitable for obtaining the effects of the present invention, is 0.01% by mass or more, 0.05% by mass or more, 0.1% by mass or more, and 0.3% by mass or more.

[0052] The liquid mulch-forming composition of the present invention uses (A) a resin and (B) a surfactant, particularly (B1) a surfactant with a molecular weight of more than 5000, which makes the resin particles finer. This promotes the penetration of the liquid mulch-forming composition into soil, etc., and contributes to the formation of a solidified layer that is thick, strong, and permeable. The particle size of the resin particles of (A) resin dispersed in (C) an aqueous solvent is not particularly limited, but as an example, it can be smaller than 1.0 μm.

[0053] The liquid multi-forming composition of the present invention may contain other components not shown above, as long as they do not impair the effects of the present invention. These other components are not particularly limited, but examples include viscosity modifiers, pH adjusters, pH buffers, preservatives, and defoamers. These may be used individually or in combination of two or more.

[0054] <Manufacturing method> The method for producing the liquid multi-forming composition of the present invention is not particularly limited, but for example, it can be produced by appropriately mixing and stirring each component using a stirrer or the like. The mixing order of the components is not particularly limited. Among these, from the viewpoint of stabilizing the (A) resin more stably in an (C) aqueous solvent with the (B) surfactant and exhibiting the effects of the present invention, it is preferable that the composition is a compound of an aqueous resin dispersion containing the (A) resin and a portion of the (B) surfactant and an aqueous solution containing the remainder of the (B) surfactant. Specifically, an aqueous resin dispersion containing the (A) resin and a portion of the (B) surfactant is prepared in advance, while an aqueous solution containing the remainder of the (B) surfactant is prepared separately. These are then mixed to obtain the liquid multi-forming composition of the present invention. In the present invention, where the mass ratio of (A) resin to (B) surfactant is 0.2 or more, there is a concern that combining (A) resin and (B) surfactant at the same time may impair stability during the resin particle formation stage. However, by preparing a resin aqueous dispersion containing (A) resin and a portion of (B) surfactant in advance, a fine and stable resin particle dispersion can be formed, and then by mixing it with the remaining (B) surfactant, the resin particles can be stabilized. This promotes the penetration of the liquid mulch-forming composition into soil, etc., and contributes to the formation of a solidified layer that is thick, strong, and permeable. Among these, considering these points, it is preferable that the mixture is a resin aqueous dispersion containing (A) resin and (B1) a surfactant with a molecular weight of more than 5000, and an aqueous solution containing (B2) a surfactant with a molecular weight of 5000 or less. Specifically, (B2) a resin aqueous dispersion containing a surfactant with a molecular weight of 5000 or less is prepared in advance, while (A) a resin and (B1) a surfactant with a molecular weight of more than 5000 are prepared separately. Then, these are mixed to obtain the liquid multi-forming composition of the present invention.(B2) By preparing an aqueous resin dispersion containing (A) resin and (B1) surfactant with a molecular weight greater than 5000 without incorporating surfactants with a molecular weight of 5000 or less, a fine and stable resin particle dispersion can be formed. Subsequently, by mixing it with (B2) surfactants with a molecular weight of 5000 or less, the resin particles can be stabilized, thereby promoting the penetration of the liquid mulch-forming composition into soil, etc., and contributing to the formation of a solidified layer that is thick, strong, and permeable.

[0055] A specific method for pre-preparing an aqueous resin dispersion containing (A) resin and a portion of (B) surfactant is to stir-mix an organic solvent, water, (A) resin, a portion of (B) surfactant, etc., in a sealed tank equipped with a stirring device, and then remove the organic solvent under reduced pressure. The stirring and mixing may be performed under heating to dissolve and disperse the solid raw materials, followed by cooling, and then the organic solvent may be removed. The organic solvent is not particularly limited, but examples include ester-based organic solvents, chlorine-based organic solvents, aromatic hydrocarbons, etc. Other methods include dispersing (A) resin under heating and pressurization without using an organic solvent, or a phase inversion method.

[0056] The liquid multi-forming composition of the present invention may be prepared by simultaneously blending (A) a resin, (B) a surfactant, and (C) an aqueous solvent to produce a resin aqueous dispersion, which may then be used as the liquid multi-forming composition. Specifically, the method described above as a way to pre-prepare a resin aqueous dispersion containing (A) a resin and a portion of (B) a surfactant can be applied.

[0057] <Application>

[0058] The liquid mulch-forming composition of the present invention is not particularly limited in terms of its application to the following: bare slopes, embankments, reclaimed land, and bare land in developed areas resulting from tunnel construction, road construction, etc.

[0059] The method for applying the liquid mulch-forming composition of the present invention to the soil surface is not particularly limited and can be carried out by spraying, etc. For example, the liquid mulch-forming composition may be diluted with water as needed, taking into consideration the workability and spraying efficiency during spraying, and then sprayed. The method of spraying onto the soil is not particularly limited and can be carried out using conventionally known methods such as shower nozzles, sprayers, and sprinklers.

[0060] For sand drift prevention applications, for example, by diluting the liquid mulch-forming composition of the present invention with water as needed and spraying it on an outdoor slope, the sprayed liquid mulch-forming composition forms a thick and strong solidified layer on the soil surface, thereby preventing dust from scattering from the soil surface. The liquid mulch-forming composition of the present invention has a plant growth promoting effect, and as a secondary effect of plant root growth, it can further improve the soil solidification performance.

[0061] Similarly, for erosion prevention applications, for example, by diluting the liquid mulch-forming composition of the present invention with water and spraying it on an outdoor slope, the sprayed liquid mulch-forming composition forms a thick and strong solidified layer on the soil surface, thereby preventing rapid erosion caused by wind and rain.

[0062] The liquid mulch-forming composition of the present invention can be suitably used as a seed-containing growth substrate material, such as a greening substrate or a vegetation substrate. Growth substrates such as greening substrates and vegetation substrates are created on slopes such as embankments and cuts associated with the construction of land, roads, dams, etc., and on bare slopes and embankments on hillsides that are difficult to green due to development work or disasters, with the aim of regenerating topsoil where plants can grow. A growth substrate material containing the liquid mulch-forming composition of the present invention can be used to create a growth substrate by spraying, etc., and allows for dense plant growth through germination and growth. For example, by mixing the liquid mulch-forming composition of the present invention with water, seeds, and other necessary materials such as soil, fertilizer, and seed spraying curing material, and spraying it on an outdoor slope, temporary soil erosion can be prevented immediately after spraying due to the solidification of the soil surface by the liquid mulch-forming composition, and soil stabilization can be achieved by the plants that germinate and grow thereafter. The liquid mulch-forming composition of the present invention is effective in bonding fine soil particles due to its fine particle size, contributing to improved soil aggregation and water retention, and enhancing plant growth. Its permeability ensures good drainage, promoting rainwater infiltration into the soil and reducing the amount of rainwater lost as surface water. Furthermore, its water retention prevents poor plant germination and wilting due to soil dryness, resulting in good growth and providing erosion prevention. [Examples]

[0063] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. 1. Preparation of liquid multi-forming composition In the examples and comparative examples, the following components were used for the liquid multi-forming composition. [Aqueous resin dispersion] Resin aqueous dispersion 1: Vinyl acetate resin aqueous dispersion ((A) vinyl acetate resin 8% by mass, (B1) surfactant with molecular weight exceeding 5000 8% by mass) Resin aqueous dispersion 2 Polylactic acid resin aqueous dispersion ((A) 8% by mass of polylactic acid with a molecular weight of 400,000, (B1) 8% by mass of surfactant with a molecular weight of over 5,000) Resin aqueous dispersion 3 Polycaprolactone resin aqueous dispersion 1 ((A) 8% by mass of polycaprolactone with a molecular weight of 64,000, (B1) 8% by mass of a surfactant with a molecular weight exceeding 5000) Resin aqueous dispersion 4 Polycaprolactone resin aqueous dispersion 2 ((A) 8% by mass of polycaprolactone with a molecular weight of 64,000, (B1) 0.1% by mass of a surfactant with a molecular weight exceeding 5000) Resin aqueous dispersion 5 Polycaprolactone resin aqueous dispersion 3 ((A) 0.8% by mass of polycaprolactone with a molecular weight of 64,000, (B1) 0.8% by mass of a surfactant with a molecular weight exceeding 5000)

[0064] For the above (B1) surfactant with a molecular weight exceeding 5000, polyvinyl alcohol (molecular weight: 100,000, saponification degree: 80%) was used respectively. The molecular weight of polyvinyl alcohol is the value calculated from the viscosity average degree of polymerization, saponification degree, and the molecular weights of vinyl acetate units and vinyl alcohol units described in JIS K 6726 as described above.

[0065] The molecular weight of the biodegradable resin is the weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography under the following apparatus and conditions. <GPC measuring apparatus> Column: Manufactured by JASCO Corporation Detector: RI detector for liquid chromatogram RI-1530 manufactured by JASCO Corporation [Measurement conditions] Solvent: Chloroform (special grade) Measurement temperature: 50 °C Flow rate: 1.0 ml / min Sample concentration: 15 mg / ml Injection volume: 2 μl Calibration curve: Universal Calibration Analysis program: ChromNAV (Ver.1.19.02)

[0066] [(B1) Surfactant with a molecular weight exceeding 5000] Polyvinyl alcohol Molecular weight: 1,00,000 Saponification degree: 80% [(B2) Surfactants with a molecular weight of 5000 or less] Polyoxyethylene (5 molar) nonylphenyl ether (molecular weight 400) Polyoxyethylene (20 mol) oleyl ether (molecular weight 1150) A copolymer of ethylene oxide (EO) and propylene oxide (PO) (polypropylene glycol ethylene oxide adduct). Number average molecular weight: 3300. EOPO ratio (EO:PO) = 46:54 Sodium dioctyl sulfosuccinate (molecular weight 445) Polyoxyethylene (2 moles) lauryl ether potassium phosphate (molecular weight 372)

[0067] Each component was placed in a sealed dispersion tank according to the component ratios shown in Tables 1A to 1C. Then, 1.5 times the amount of ethyl acetate was added to the deionized water, and the mixture was heated to 65°C and dispersed using a predetermined stirring dispersion apparatus. After dispersion, the mixture was rapidly cooled to 40°C. Subsequently, the ethyl acetate was removed under reduced pressure to obtain resin aqueous dispersions 1 to 5.

[0068] In Examples 1-14 and Comparative Examples 1 and 2, a liquid mulch-forming composition was obtained by mixing two solutions: a resin aqueous dispersion and an aqueous solution of (B2) a water permeable agent among (B) surfactants. In Examples 15 and Comparative Example 3, a single resin aqueous dispersion was used as the liquid mulch-forming composition. In the comparison between Examples 15 and 16, a comparison was made between a single solution (Example 15) and a two-solution solution (Example 16). In Example 16, (B1), which corresponds to the difference between the resin aqueous dispersion 5 used in Example 15 and the resin aqueous dispersion 4 used in Example 16, was added to form a second aqueous solution, which was then mixed with the first resin aqueous dispersion 4 to form a liquid mulch-forming composition. Comparative Example 4 used an aqueous solution of (B1) a surfactant with a molecular weight of over 5000.

[0069] 2. Evaluation The liquid multi-forming compositions of the examples and comparative examples were evaluated as follows.

[0070] (1) Layer properties [Thickness] Vegetation base material was prepared in stainless steel trays with the following composition ratios (mass) to a thickness of 10 cm. Using these, liquid mulch-forming compositions were sprayed onto the stainless steel trays in the ratios listed in Tables 1A to 1C without tilting them, and after being left outdoors for one day, the thickness of the sprayed surface was measured. It was determined that the problem of the invention could be solved if the result was ○ or greater. Composition of vegetation substrate Bark compost: 50% Peat moss: 20% Black soil: 30% Evaluation Criteria ◎++: 6cm or larger ◎+: 5cm or more, less than 6cm ◎: 3cm or more but less than 5cm ○: 2cm or more but less than 3cm △: 1cm or more but less than 2cm ×: Less than 1cm Figure 1 shows the state after spraying the liquid mulch-forming compositions of Example 1 and Comparative Example 3 onto a vegetation substrate and allowing them to penetrate, as well as a photograph of the solidified layer removed from there.

[0071] [Water permeability] Vegetation substrate material was prepared in stainless steel trays with the above composition ratio (mass) to a thickness of 10 cm. Using these, liquid mulch-forming compositions were sprayed onto the stainless steel trays in the ratios listed in Tables 1A to 1C without tilting them, and after being left outdoors for one day, 5 ml of water was irrigated from above and the penetration speed of the surface was measured. Evaluation Criteria ◎+: Less than 3 seconds ◎: 3 seconds or more but less than 6 seconds ○: 6 seconds or more but less than 8 seconds △: 8 seconds or more but less than 10 seconds ×: More than 10 seconds

[0072] [Strength] Vegetation substrate material was prepared in stainless steel trays with the above composition ratio (mass) to a thickness of 10 cm. Using these trays, liquid mulch-forming compositions were sprayed onto the stainless steel trays in the ratios listed in Tables 1A to 1C without tilting them, and left outdoors for one day. The surface strength was then measured. Using a digital force gauge, the strength (N) was measured after 60 days and 180 days and evaluated according to the following criteria. ◎+: 30 or more ◎: 20 or more and less than 30 ○: 10 or more and less than 20 △: 5 or more, less than 10 ×: Less than 5

[0073] (2) Sand drift prevention test Place decomposed granite soil (particle size 10 mm or less) in a stainless steel tray, and add the liquid mulch-forming compositions of the examples and comparative examples to it at a rate of 250 g / m² of active ingredient. 2 The plants were sprayed and then left to cure. [Amount of dust scattered] After 60 and 180 days, a blower was operated on the test specimen (wind speed 10 m / s x 5 minutes), and the amount of dust dispersed was measured and evaluated according to the following criteria. ◎++: Less than 5% ◎+: 5% or more but less than 10% ◎: 10% or more but less than 30% ○: 30% or more but less than 40% △: 40% or more but less than 50% ×: 50% or more

[0074] (3) Erosion prevention test Vegetation base materials were prepared in stainless steel trays with the following composition ratio (mass), and these were used to implement the topsoil spraying method and the thick-layer base material spraying method. The application sites had an incline angle of approximately 45°, and the thickness of the sprayed surface was 5 mm in both cases. Composition of vegetation substrate Bark compost: 50% Peat moss: 20% Black soil: 30% Various raw materials were mixed with 100 parts by mass of the above-mentioned vegetation base material in the following composition. Fertilizer (High Control 700 (product name) manufactured by Asahi Kasei Corporation): 0.3% Seeds (forage grass: Kentucky 31 fescue): 0.05% Liquid multi-forming compositions of the examples and comparative examples: 5%

[0075] [Whether or not it has collapsed] After being left outdoors for 30 days, a rainfall test was conducted from a height of 1 meter at 100 mm / hr for 15 minutes. The presence or absence of collapse was then measured and evaluated according to the following criteria. ◎++: Less than 5% ◎+: 5% or more but less than 10% ◎: 10% or more but less than 30% ○: 30% or more but less than 40% △: 40% or more but less than 50% ×: 50% or more

[0076] [Soil runoff] After being left outdoors for 30 days, a rainfall test was conducted from a height of 1m at 100mm / hr for 15 minutes, followed by measurement of soil runoff, which was evaluated according to the following criteria. ◎++: Less than 5% ◎+: 5% or more but less than 10% ◎: 10% or more but less than 30% ○: 30% or more but less than 40% △: 40% or more but less than 50% ×: 50% or more

[0077] The results of the above evaluation are shown in Tables 1 to 1C.

[0078] [Table 1A]

[0079] [Table 1B]

[0080] [Table 1C]

Claims

1. A liquid mulch-forming composition comprising (A) a resin and (B) a surfactant, wherein the mass ratio of (B) surfactant to (A) resin is 0.2 or more.

2. (B) The liquid multi-forming composition according to claim 1, wherein the surfactant comprises (B1) a surfactant having a molecular weight greater than 5000 and (B2) a surfactant with a molecular weight of 5000 or less.

3. The liquid multi-forming composition according to claim 1, wherein the solid content is less than 8% by mass.

4. A liquid mulch-forming composition according to any one of claims 1 to 3, comprising a resin aqueous dispersion containing (A) a resin and a portion of (B) a surfactant, and an aqueous solution containing the remainder of (B) a surfactant.

5. The liquid mulch-forming composition according to claim 2, which is a compound of (A) a resin and (B1) an aqueous resin dispersion containing a surfactant having a molecular weight of more than 5000, and (B2) an aqueous solution containing a surfactant with a molecular weight of 5000 or less.

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