Biodegradable vegetation sheet

Abstract

To provide a biodegradable vegetation sheet into which dicotyledonous plants can be introduced and which is suitable for the growth of dicotyledonous plants. [Solution] This biodegradable vegetation sheet comprises a biodegradable nonwoven fabric body 11 and a biodegradable reinforcing net 15 attached to the surface of the nonwoven fabric body 11, with plant seeds 12 and fertilizer 13 attached to the backside of the nonwoven fabric body 11, and the nonwoven fabric body 11, formed into a sheet by intertwining fibers, is made primarily from animal hair fibers, the main component of which is keratin, and the animal hair fibers are intertwined with each other using a needle punch method to form the nonwoven fabric body 11 into a sheet so as to prevent slope erosion and have a fertilizer effect while allowing plant seeds to germinate.

Description

[Technical field]

[0001] The present invention relates to a biodegradable vegetation sheet for protecting the topsoil on slopes such as cuts and fills and for greening the slopes, and in particular to a biodegradable vegetation sheet suitable for the growth of dicotyledonous plants. [Background technology]

[0002] A widely known method of slope protection is the use of vegetation sheets, which are made of a moisture-retentive sheet body to which plant seeds and fertilizer are attached. Examples of this type of vegetation sheet that have been proposed include a type of vegetation sheet whose sheet body is primarily made of chemical fibers such as polyester fibers (Patent Documents 1 to 3), and a type of vegetation sheet whose sheet body contains biodegradable fibers such as cotton (Patent Documents 4 and 5). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 10-183630 [Patent Document 2] JP 2002-199811 A [Patent Document 3] JP 2010-101105 A [Patent Document 4] Japanese Patent Application Publication No. 7-138957 [Patent Document 5] Japanese Patent Application Publication No. 9-187165 Summary of the Invention [Problem to be solved by the invention]

[0004] Conventional vegetation sheets, which are mainly made of chemical fibers, have the following problems: <1> While synthetic fibers have excellent strength properties, they also have a large environmental impact due to the CO2 emissions they produce. <2> Chemical fibers do not decompose even over a long period of time, so they cannot be used as fertilizer. As a result, plants have no choice but to rely on chemical fertilizers to meet the nutrients needed for plant growth, which means the manufacturing costs of vegetation sheets with chemical fertilizers attached are high. <3> In order to maintain the fixed shape of the sheet itself, the vegetation sheet is formed by binding a large number of chemical fibers with a binder material such as a chemical bond, or by compressing a large number of groups of chemical fibers. As a result, the tissue of the vegetation sheet becomes denser and the chemical fibers adhere to each other, making it difficult for the gaps formed between the chemical fibers to expand and change, making it difficult for the cotyledons of the plant to penetrate the vegetation sheet when the plant germinates. <4> Reducing the basis weight of the synthetic fiber sheet body to make it coarser improves plant germination, but significantly reduces the effectiveness of the vegetation sheet in preventing slope erosion.

[0005] Conventional vegetation sheets containing biodegradable fibers in the sheet body have the following problems. <1> If the sheet body is formed thick in order to ensure a sufficient layer thickness of biodegradable fibers, not only will sunlight be blocked, creating an environment that is difficult for plant seeds to germinate, but it will also be difficult for cotyledons that germinate from the plant seeds to penetrate the sheet body. <2> Making the sheet thinner can improve the environment for plant seeds to germinate, but it also makes the slope more susceptible to erosion due to rainfall.

[0006] Conventional vegetation sheets that are mainly made of chemical fibers and conventional vegetation sheets that contain biodegradable fibers in the sheet body have the following common problems. <1> The tissue of the sheet itself is made up of numerous fiber groups, making it difficult for the cotyledons of the plant to penetrate the sheet itself. Therefore, if the seeds of dicotyledonous plants that germinate with two cotyledons are used as plant seeds, the cotyledons of the dicotyledonous plants cannot penetrate the main body of the sheet, and the plant seeds that can be introduced into the vegetation sheet are limited to monocotyledonous plants that germinate with one cotyledon.

[0007] The present invention aims to solve the above problems, enable the introduction of dicotyledonous plants, which was difficult to do with conventional vegetation sheets, and provide a biodegradable vegetation sheet suitable for the growth of dicotyledonous plants. [Means for solving the problem]

[0008] The present invention relates to a biodegradable vegetation sheet comprising a nonwoven fabric body formed into a sheet-like shape by intertwining biodegradable fibers and having plant seeds and fertilizer attached to the back side, the nonwoven fabric body being made primarily from animal hair fibers whose main component is keratin, and the animal hair fibers are intertwined with each other using a needle punch method to form the nonwoven fabric body into a sheet-like shape so as to enable the germination of plant seeds while retaining the effect of preventing slope erosion and providing fertilizer. In another embodiment of the present invention, the nonwoven fabric main body has a sheet thickness of 0.5 to 2 mm, and a puncture strength of 0.03 to 0.3 N. In another embodiment of the present invention, the animal hair fiber has a fiber length of 20 to 80 mm, a fiber width of 0.02 to 0.06 mm, and a basis weight of 50 to 150 g / m 2 It is. In another embodiment of the present invention, the animal hair fibers include any one or more of wool, mohair, cashmere, camel, alpaca, llama, angora rabbit, and the like. In another aspect of the invention, the nonwoven body may comprise biodegradable cotton or rayon. In another embodiment of the present invention, a biodegradable reinforcing net may be attached to the surface of the nonwoven fabric body. In another embodiment of the present invention, the reinforcing net has a mesh size that allows plant seeds to germinate and grow. In another embodiment of the invention, the plant seed comprises at least a dicotyledonous plant. Effect of the Invention

[0009] The present invention has at least one of the following advantages. <1> Animal hair fibers primarily composed of keratin are used as the biodegradable fibers in the nonwoven fabric body that constitutes the biodegradable vegetation sheet, and the animal hair fibers are intertwined with each other using a needle punching method, thereby providing a nonwoven fabric body that has both an anti-erosion effect on slopes and a fertilizer effect. <2> By selecting the sheet thickness of the nonwoven fabric body, the puncture strength of the nonwoven fabric body, the sheet thickness of the nonwoven fabric body, the puncture strength of the nonwoven fabric body, the fiber length of the animal hair fibers, the fiber width of the animal hair fibers or the basis weight of the animal hair fibers, it becomes possible to introduce dicotyledonous plants that have been difficult to introduce until now. <3> The animal hair fibers constituting the nonwoven fabric main body are intertwined with each other in a state in which the animal hair fibers can move. Therefore, when the plant seeds germinate, the cotyledons push aside the animal hair fibers in the nonwoven fabric body and grow while expanding the gaps, making it easier for the cotyledons to penetrate the vegetation sheet when germinating. <4> As the plant seeds can be introduced, not only monocotyledonous plants but also dicotyledonous plants can be introduced, which greatly expands the options for greening plants using vegetation sheets. <5> By combining fertilizer pre-applied to the biodegradable vegetation sheet with the nonwoven fabric body that functions as a slow-release fertilizer, a good fertilization environment can be maintained not only at the time of germination but also for a long period of time after germination in accordance with the growth of the plants. <6> Since the nonwoven fabric body functions as an effective fertilizer, the amount of fertilizer that is pre-applied to the biodegradable vegetation sheet can be reduced. [Brief description of the drawings]

[0010] [Figure 1] An explanatory diagram of the biodegradable vegetation sheet according to the present invention. [Diagram 2] Diagram of the decomposition of the biodegradable vegetation sheet [Diagram 3] An explanatory diagram of the nonwoven fabric that constitutes the biodegradable vegetation sheet [Figure 4] Enlarged structure of the nonwoven fabric with a basis weight of 50g / m3 [Diagram 5] Enlarged structure of the nonwoven fabric with a basis weight of 100g / m3 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The biodegradable vegetation sheet according to the present invention will be described below with reference to the drawings.

[0012] <1> Overview of biodegradable vegetation sheets The following description will be given with reference to Figures 1 and 2. The biodegradable vegetation sheet 10 according to the present invention (hereinafter referred to as "vegetation sheet 10") is a nonwoven fabric sheet for protecting the topsoil on the slopes of cut earth, banking earth, etc., and for greening the slopes. The vegetation sheet 10 according to the present invention comprises a biodegradable nonwoven fabric main body 11 having a substantially rectangular shape, and a biodegradable reinforcing net 15 bonded integrally to the surface 11a of the nonwoven fabric main body 11. The nonwoven fabric body 11 is a sheet-like material having water permeability and air permeability, and the back surface 11b thereof has plant seeds 12 and fertilizer 13 sprayed and glued thereon. The reinforcing net 15 is not essential, and may be omitted.

[0013] The present invention focuses on animal hair fibers as the biodegradable fibers that make up the nonwoven fabric body 11. By using animal hair fibers, we conducted repeated demonstration experiments to develop a vegetation sheet that has excellent slope erosion prevention properties, fertilizer properties, and water and heat retention properties, while also allowing dicotyledonous plant seeds to germinate. As a result, the inventors discovered an optimal combination of values ​​for the fiber length, fiber width, and basis weight of the animal hair fibers, and the penetration resistance of the vegetation sheet, leading to the completion of the present invention. The vegetation sheet 10 will be described in detail below.

[0014] <2.1> Sheet thickness of nonwoven fabric body The sheet thickness of the nonwoven fabric body 11 is preferably in the range of 0.5 mm to 2 mm. If the sheet thickness is thinner than 0.5 mm, the erosion suppression effect of the vegetation sheet 10 will be reduced, and if the sheet thickness is thicker than 2 mm, the penetration of the nonwoven fabric body 11 by the cotyledons of the plants will be hindered.

[0015] <2.2> Nonwoven fabric body material The nonwoven fabric body 11 is made primarily of animal hair fibers containing keratin as the main component. The animal hair fibers include, for example, one or more of wool, mohair, cashmere, camel, alpaca, llama, angora rabbit, and the like. Considering processability, availability, and cost, wool is a suitable material for the nonwoven fabric body 11.

[0016] Until now, animal hair fibers have been disposed of as waste, but by using these animal hair fibers as greening materials for slopes, the amount of animal hair fibers disposed of as waste can be significantly reduced.

[0017] The fibers constituting the nonwoven fabric body 11 may be 100% animal hair fibers, but the animal hair fibers may contain biodegradable cotton and / or rayon in part. Furthermore, it is also possible to add biodegradable plastics such as polylactic acid and biodegradable chemical fibers such as polyester.

[0018] <2.3> Means for forming nonwoven fabric into sheets An aggregate of animal hair fibers or the like is formed into a sheet using the needle punch method. By piercing a large number of animal hair fibers over the entire surface from both sides with a large number of needles, the large number of animal hair fibers can be integrated, and both the front surface 11a and the back surface 11b of the nonwoven fabric body 11 become raised, improving the fixation and germination of the plant seeds 12 and fertilizer 13.

[0019] <2.4> Fiber length The fiber length of the fibers constituting the nonwoven fabric body 11 is preferably in the range of 20 to 80 mm. If the fiber length is less than 20 mm, the animal hair fibers will not easily entangle and will be difficult to form into a sheet. If the fiber length of the nonwoven fabric body 11 is greater than 80 mm, the penetration of the nonwoven fabric body 11 by the cotyledons of plants, particularly the cotyledons of dicotyledonous plants, is hindered.

[0020] <2.5> Fiber width The fiber width (cross-sectional dimension) of the fibers constituting the nonwoven fabric body 11 is preferably in the range of 0.02 to 0.06 mm. FIG. 4 shows an enlarged view of animal hair fibers (wool) with a fiber width of 0.02 mm, and FIG. 5 shows an enlarged view of animal hair fibers (wool) with a fiber width of 0.04 to 0.05 mm.

[0021] If the fiber width of the nonwoven fabric body 11 is less than 0.02 mm, the fibers will not easily intertwine, making it difficult to form a sheet. If the fiber width of the nonwoven fabric body 11 is greater than 0.06 mm, the cotyledons of plants, particularly those of dicotyledonous plants, are prevented from penetrating the nonwoven fabric body 11 .

[0022] <2.6> Weight The weight per unit area of ​​the nonwoven fabric constituting the nonwoven fabric body 11 is 40 to 150 g / m 2 A range of is desirable. Figure 4 shows the basis weight of 50g / m 2 FIG. 5 shows a nonwoven fabric body 11 having a basis weight of 100 g / m 3 The nonwoven fabric body 11 is shown.

[0023] The weight of the nonwoven fabric is 40g / m 2 If it is smaller, unevenness in basis weight is likely to occur during the production of the nonwoven fabric body 11. If unevenness in the basis weight occurs, it is likely to induce unevenness in the erosion prevention effect and vegetation potential, and the fertilizer effect of the biodegradable fibers will not be sufficient. The weight of the nonwoven fabric is 150g / m 3 If it is larger, the shading effect will be stronger, worsening the germination environment for plants.

[0024] <2.7> Penetration resistance (puncture strength) of nonwoven fabric body Nonwoven fabric body 11 was tested for a suitable penetration resistance (puncture strength) so that nonwoven fabric body 11 could be quickly penetrated even in the case of dicotyledonous plants whose cotyledons do not have sharp tips. The puncture strength test is a test based on JIS Z 1707 "General rules for food-use plastic films" and is the force required to make a hole when the nonwoven fabric body 11 is pierced with a 0.5R·1mmΦ needle at a speed of 50 mm / min.

[0025] As a result, the penetration resistance of the nonwoven fabric body 11 in a puncture strength test is 0.3 N or less, and desirably 0.03 N or more. If the penetration resistance of nonwoven fabric body 11 in a puncture strength test exceeds 0.3 N, the penetration resistance of nonwoven fabric body 11 becomes so large that the penetration of nonwoven fabric body 11 by plant cotyledons, particularly cotyledons of dicotyledonous plants, is hindered. If the penetration resistance of the nonwoven fabric body 11 in a puncture strength test is less than 0.03 N, the soil particle capture ability decreases, and the erosion suppression effect of the vegetation sheet 10 deteriorates.

[0026] (Newtons), the larger the value, the stronger, and the smaller the value, the weaker. <3> Plant seeds that can be introduced The plant seeds 12 that can be attached to the nonwoven fabric body 11 can be either dicotyledonous or monocotyledonous plants, or a mixture of both. The reason why dicotyledonous plants can be introduced will be described later.

[0027] From the perspective of biodiversity conservation, it is desirable to use seeds of native plants that are indigenous to Japan whenever possible. As the plant seeds 12, various seeds of dicotyledonous plants as well as monocotyledonous plants can be introduced, so that the selection of greening plants using the vegetation sheet 10 is expanded.

[0028] <3.1>Dicotyledonous plants As the dicotyledonous plant, any one of the plants exemplified below can be used alone or in combination. ●Leguminous plants (Japanese bush clover, Japanese bush clover, etc.) Asteraceae plants (mugwort, etc.) ● Legumes (such as vetch and summer peas) Polygonaceae plants (Rumex obtusifolius, Rumex tenuifolia, Sorrel, etc.) - Anacardiaceae plants (such as sumac, Japanese lacquer tree, etc.) ●Oleaceae plants (lilac, lilac, sweet osmanthus, etc.) Euphorbiaceae plants (plants belonging to the genera Euphorbia, Acalypha, and Scutellaria, etc.) - Elaeaceae plants (Elastomataceae, Elastomataceae, Elastomataceae, etc.) Rosaceae plants Ericaceae plants

[0029] Furthermore, as dicotyledonous plants, any one or a combination of several types of plants such as European mustard, Japanese knotweed, Japanese laurel, onyx, thistle, eggplant, bamboo grass, violet, Japanese hazel, sowberry, chickweed, Japanese chestnut, Japanese mimosa, and American pokeweed can be used.

[0030] <3.2> Monocotyledonous plants As monocotyledonous plants, known seeds of plants of the Gramineae family (crabgrass, green foxtail, goosegrass, annual bluegrass, corn, etc.), plants of the Commelinaceae family (dayflower, Japanese laurel, wild ginger), plants of the Miscanthus genus (Japanese silverleaf, Miscanthus albicilla, Striped silverleaf) and the like can be used.

[0031] <4> fertilizer The fertilizer 13 applied to the nonwoven fabric body 11 may be of any type (chemical fertilizer, organic fertilizer) as long as it is one that is normally used as a fertilizer for plants. As the fertilizer 13, for example, a nitrogen-based fertilizer (G), a phosphorus-based fertilizer (P), and a potassium-based fertilizer (K) are appropriately mixed and used. In the present invention, the nonwoven fabric body 11 functions as a slow-acting fertilizer, so that the amount of fertilizer 13 adhered can be reduced.

[0032] <5> Reinforcement net For the reinforcing net 15, a net material made of biodegradable material (a net made of plant fibers such as hemp string), resin (chemical net), or metal (wire mesh) can be used. The mesh size of the reinforcing net 15 is such that it does not adversely affect the germination and growth of plants. As the biodegradable plant fiber material, for example, hemp, coconut, and animal hair fibers can be used. In this embodiment, a form in which a hemp net material is attached to one side of the nonwoven fabric body 11 as the reinforcing net 15 will be described.

[0033] By bonding the reinforcing net 15 to one side of the nonwoven fabric body 11, the strength of the nonwoven fabric body 11 is increased, improving the stability of the sheet when applied to a slope or the like.

[0034] [Slope protection method using vegetation sheets] A slope protection method using the vegetation sheet 10 will be described.

[0035] <1> Laying vegetation sheets After removing weeds, loose stones, etc. from the slope, a vegetation sheet 10 is laid on the slope. When laying the vegetation sheet 10, the back surface 11b of the vegetation sheet 10 is spread out toward the slope, and fixing pins such as anchor pins or bamboo skewers are driven into multiple points of the vegetation sheet 10 to fix it in place.

[0036] <2> Plant germination environment By limiting the dimensions and basis weight of the animal hair fibers constituting the nonwoven fabric body 11 to specific ranges, sunlight can be incident on the back side of the vegetation sheet 10, creating a good environment for the plant seeds 12 to germinate.

[0037] <3> Cotyledon elongation of plant seeds The germinated cotyledons of the plant seeds 12 penetrate between the animal hair fibers of the nonwoven fabric body 11 constituting the vegetation sheet 10 to the surface side, and then penetrate the meshes of the reinforcing net 15 and grow to the ground surface.

[0038] In particular, since the animal hair fibers of the nonwoven fabric body 11 are simply intertwined with each other in a state in which the animal hair fibers can move, the gaps formed between the animal hair fibers can expand and narrow in accordance with the displacement of each animal hair fiber. Therefore, the cotyledons of the plant seed 12 push aside the animal hair fibers of the nonwoven fabric body 11 and grow upward while expanding the gaps.

[0039] Therefore, even if the plant seeds 12 are dicotyledonous plants, they can penetrate the vegetation sheet 10 and germinate. When the plant seed 12 is a monocotyledonous plant, the cotyledons can penetrate the vegetation sheet 10 more easily.

[0040] <4> Growth environment of plants after germination In the vegetation sheet 10 according to the present invention, when the plant seeds 12 germinate, the fertilizer 13 attached to the vegetation sheet 10 functions to release fertilizer components. In other words, when the plant seeds 12 germinate, the biodegradable nonwoven fabric body 11 has not yet been fully converted into fertilizer, and so the fertilizer 13 mainly releases the fertilizer components.

[0041] The animal hair fibers, which are the main raw material of the nonwoven fabric body 11, contain a lot of protein, and as the animal hair fibers biodegrade in the soil, nitrogen (N) is generated and the resulting fertilizer can be used. In this way, the biodegradable animal hair fibers constituting the nonwoven fabric body 11 gradually biodegrade over time.

[0042] Therefore, the germinated plants grow by receiving the release of fertilizer components from both the fertilizer 13 and the nonwoven fabric body 11 . The fertilizer 13 quickly stops releasing the fertilizer components, but the nonwoven fabric body 11 containing the biodegradable fiber components continues to release small amounts of the fertilizer components over several months. The biodegradation of the nonwoven fabric body 11 progresses over a long period of time, so that the nonwoven fabric body 11 functions as a slow-acting fertilizer material.

[0043] In this way, the combination of fertilizer 13 and nonwoven fabric body 11 can maintain a good fertilization environment not only during germination but also for a long period of time after germination in accordance with the growth of the plants.

[0044] <5> Various functions of vegetation sheets The vegetation sheet 10 according to the present invention not only functions as fertilizer as described above, but also has a number of other functions as will be described below.

[0045] <5.1> Slope topsoil runoff prevention effect The vegetation sheet 10 according to the present invention has dimensions and basis weight of the animal hair fibers which are the main raw material, which are set so as to be able to suppress the loss of topsoil from slopes. Therefore, the vegetation sheet 10 exerts a high erosion prevention effect by pressing down the entire slope of the target planting area.

[0046] <5.2> Regulation of soil temperature The animal hair fibers, which are the main raw material of the vegetative sheet 10 of the present invention, contain a lot of air and have excellent heat insulating properties. Furthermore, animal hair fibers are known to generate heat when they absorb moisture. These functions prevent the soil from freezing in winter and raise the ground temperature during the low temperatures of spring and autumn, thereby maintaining a good growing environment for introduced plants all year round.

[0047] <5.3> Wild animal repellent effect The main raw material of the vegetative sheet 10 of the present invention contains animal hair fibers. When the animal hair fiber is wool, the wool has a unique odor. The unique odor of wool acts as a repellent for wild animals such as deer and wild boar. This makes it possible to prevent wild animals from entering areas greened with vegetation sheets, and effectively avoid damage to slopes and feeding damage caused by wild animals. [Explanation of symbols]

[0048] 10. Biodegradable vegetation sheet (vegetation sheet) 11...Nonwoven fabric body 11a: Surface of nonwoven fabric body 11b Back side of nonwoven fabric body 12...plant seeds 13...Fertilizer 15 Reinforcement sheet

Claims

1. A biodegradable vegetation sheet comprising a nonwoven fabric body having plant seeds and fertilizer attached to the back surface thereof and formed into a sheet shape by intertwining biodegradable fibers, The plant seeds include at least a dicotyledonous plant, The nonwoven fabric body is made primarily of animal hair fibers composed mainly of keratin, The animal hair fibers are entangled with each other by a needle punch method to form the nonwoven fabric body into a sheet while maintaining the effect of preventing erosion of slopes and the effect of fertilizer; The sheet thickness of the nonwoven fabric body is 0.5 to 2 mm, The puncture strength of the nonwoven fabric body is 0.03 to 0.3 N, The animal hair fiber has a basis weight of 40 to 150 g / m 2 ; The nonwoven fabric body is configured so that the cotyledons of the dicotyledonous plant can penetrate the nonwoven fabric body. Biodegradable vegetation sheet.

2. The fiber length of the animal hair fiber is 20 to 80 mm; The animal hair fiber has a fiber width of 0.02 to 0.06 mm. The biodegradable vegetation sheet according to claim 1.

3. 2. The biodegradable vegetation sheet according to claim 1, wherein the animal hair fiber comprises one or more of wool, mohair, cashmere, camel, alpaca, llama, angora rabbit, and the like.

4. 2. The biodegradable vegetation sheet according to claim 1, wherein the nonwoven fabric body comprises biodegradable cotton or rayon.

5. 2. The biodegradable vegetation sheet according to claim 1, wherein a biodegradable reinforcing net is attached to the surface of the nonwoven fabric body.

6. 6. The biodegradable vegetation sheet according to claim 5, wherein the mesh size of the reinforcing net is such that plant seeds can germinate and grow.

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