Biodegradable vegetation sheet

Abstract

To provide a biodegradable vegetation sheet that allows for the introduction of dicotyledonous plants and is suitable for the growth of dicotyledonous plants. [Solution] A biodegradable vegetation sheet comprising a biodegradable nonwoven fabric body 11 and a biodegradable reinforcing net 15 attached to the surface of the nonwoven fabric body 11, wherein plant seeds 12 and fertilizer 13 are attached to the back surface of the nonwoven fabric body 11, and the nonwoven fabric body 11, which is formed into a sheet by intertwining fibers, is mainly made of animal hair fibers with keratin as the main component, and the animal hair fibers are intertwined with each other by a needle punching method to form the nonwoven fabric body 11 into a sheet, which has slope erosion prevention effect and fertilizer effect, while enabling the germination of plant seeds.

Description

Technical Field

[0001] The present invention relates to a biodegradable vegetation sheet for protecting topsoil and greening slopes in earth cutting, embankment, etc., and particularly to a biodegradable vegetation sheet suitable for the growth of dicotyledonous plants.

Background Art

[0002] A slope protection method using a vegetation sheet in which plant seeds and fertilizers are attached to a moisture-retaining sheet body is widely known. As this type of vegetation sheet, there have been proposed a vegetation sheet in which the sheet body is mainly made of chemical fibers such as polyester fibers (Patent Documents 1 to 3), and a vegetation sheet in which the sheet body contains biodegradable fibers such as cotton (Patent Documents 4 and 5).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0004] Conventional vegetation sheets mainly made of chemical fibers have the following problems. , <1>While chemical fibers have excellent strength characteristics, they have a large environmental load due to CO2. <2>Since chemical fibers are not decomposed even after a long period of time, they do not become fertilizer. Therefore, because the nutrients necessary for plant growth must be obtained from chemical fertilizers, the manufacturing cost of vegetation sheets with chemical fertilizers attached is high. <3> To maintain the shape of the sheet itself, the vegetation sheet is formed by binding together numerous chemical fibers with a binder material such as chemical bond, or by compressing a large group of chemical fibers. Therefore, as the structure of the vegetation sheet becomes denser and the chemical fibers adhere to each other, the gaps formed between the chemical fibers do not expand or change easily, making it difficult for the cotyledons of plants to penetrate the vegetation sheet when they germinate. <4> Reducing the weight of the synthetic fiber sheet to create a coarser structure improves plant germination, but significantly reduces the erosion-preventing effect of the vegetation sheet on slopes.

[0005] Conventional vegetation sheets that contain biodegradable fibers in the sheet itself have the following problems: <1> If the sheet itself is made thick to ensure sufficient layer thickness of biodegradable fibers, not only will sunlight be blocked, creating an environment where plant seeds are less likely to germinate, but the cotyledons that germinate from the plant seeds will also have difficulty penetrating the sheet itself. <2> Making the sheet itself thinner can improve the germination environment for plant seeds, but it makes the slope more susceptible to erosion from rainfall.

[0006] Conventional vegetation sheets primarily made of synthetic fibers and conventional vegetation sheets containing biodegradable fibers in the sheet itself share the following common problems. <1> The sheet itself has a structure in which numerous fiber clusters are gathered together, making it difficult for plant cotyledons to penetrate the sheet. Therefore, if dicotyledonous plant seeds, which germinate with two cotyledons, are used, the cotyledons of the dicotyledonous plant cannot penetrate the sheet itself, limiting the plant seeds that can be introduced into the vegetation sheet to monocotyledonous plants, which germinate with one cotyledon.

[0007] The present invention aims to solve the above problems, enable the introduction of dicotyledonous plants which was difficult 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 by intertwining biodegradable fibers and having plant seeds and fertilizer attached to the back surface, wherein the nonwoven fabric body is mainly made of animal hair fibers with keratin as the main component, and the animal hair fibers are intertwined by a needle punching method to form the nonwoven fabric body into a sheet, while possessing slope erosion prevention and fertilizer properties, and enabling the germination of plant seeds. In another embodiment of the present invention, the sheet thickness of the nonwoven fabric body is 0.5 to 2 mm, and the puncture strength of the nonwoven fabric body is 0.03 to 0.3 N. In another embodiment of the present invention, the fiber length of the animal hair fiber is 20 to 80 mm, the fiber width of the animal hair fiber is 0.02 to 0.06 mm, and the basis weight of the animal hair fiber is 50 to 150 g / m². 2 That is the case. In another embodiment of the present invention, the animal hair fibers include one or more of the following: wool, mohair, cashmere, camel, alpaca, llama, angora rabbit, etc. In another embodiment of the present invention, the nonwoven fabric body may contain 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 mesh size of the reinforcing net is such that plant seeds can germinate and grow. In another embodiment of the present invention, the plant seeds include at least dicotyledonous plants. [Effects of the Invention]

[0009] The present invention provides at least one of the following effects. <1>By using animal hair fibers with keratin as the main component in the biodegradable fibers of the non-woven fabric body that constitutes the biodegradable vegetation sheet, and intertwining the animal hair fibers with each other by the needle punching method, it is possible to provide a non-woven fabric body that has both an erosion prevention effect and a fertilizer effect on the slope surface. <2>By selecting the sheet thickness of the non-woven fabric body, the piercing strength of the non-woven fabric body, the sheet thickness of the non-woven fabric body, the piercing strength of the non-woven 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, etc., it becomes possible to introduce dicotyledonous plants, which have hitherto been difficult to introduce. <3>The animal hair fiber group that constitutes the non-woven fabric body is intertwined with each other in a state where the animal hair fibers can move. Therefore, when the plant seeds germinate, the cotyledons grow while pushing aside the animal hair fiber group of the non-woven fabric body and expanding the gap, so the cotyledons are more likely to penetrate the vegetation sheet when germinating. <4>As plant seeds, not only monocotyledonous plants but also dicotyledonous plants can be introduced, so the options for greening plants using the vegetation sheet are significantly expanded. <5>By combining the fertilizer pre-attached to the biodegradable vegetation sheet with the non-woven fabric body that functions as a slow-release fertilizer, it is possible to maintain a good fertilization environment for a long time according to the growth of the plants not only at the time of germination but also after germination. <6>Since the non-woven fabric body functions as an effective fertilizer, the amount of fertilizer pre-attached to the biodegradable vegetation sheet can be reduced.

Brief Description of the Drawings

[0010] [Figure 1] Explanatory drawing of the biodegradable vegetation sheet according to the present invention [Figure 2] Decomposition model diagram of the biodegradable vegetation sheet [Figure 3] Explanatory drawing of the non-woven fabric body that constitutes the biodegradable vegetation sheet <M000094> [Figure 4] Enlarged tissue diagram of the non-woven fabric body with a basis weight of 50 g / m3 [Figure 5] Enlarged tissue diagram of the non-woven fabric body with a basis weight of 100 g / m3

Mode for Carrying Out the Invention

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

[0012] <1> Overview of Biodegradable Vegetation Sheets Please refer to Figures 1 and 2 for further explanation. The biodegradable vegetation sheet 10 according to the present invention (hereinafter referred to as "vegetation sheet 10") is a nonwoven fabric sheet for protecting topsoil and greening slopes such as cut and fill slopes. The vegetation sheet 10 according to the present invention consists of a biodegradable nonwoven fabric body 11 having a substantially rectangular shape and a biodegradable reinforcing net 15 integrally bonded to the surface 11a of the nonwoven fabric body 11. The nonwoven fabric body 11 is a sheet-like material that is permeable to water and breathable, and plant seeds 12 and fertilizer 13 are sprayed onto its back surface 11b and glued in place. Reinforcement net 15 is not mandatory, and it may be omitted in some cases.

[0013] This invention focuses on animal hair fibers as biodegradable fibers that constitute the nonwoven fabric body 11. In developing a vegetation sheet using animal hair fibers that possesses excellent slope erosion prevention, fertilizing, and water / heat retention properties, while also enabling the germination of dicotyledonous plant seeds, repeated field experiments were conducted. As a result, we were able to determine a suitable combination of values ​​for the fiber length, fiber width, 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 explained in detail below.

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

[0015] <2.2> Material of the nonwoven fabric itself The nonwoven fabric body 11 is primarily made from animal hair fibers with keratin as the main component. Animal hair fibers include, for example, one or more of the following: wool, mohair, cashmere, camel, alpaca, llama, Angora rabbit, etc. Considering processability, availability, and cost-effectiveness, wool is suitable as the material for the nonwoven fabric body 11.

[0016] Previously, animal hair fibers were disposed of as waste, but by utilizing these animal hair fibers as greening materials for slopes, the amount of animal hair fibers that need to be discarded can be significantly reduced.

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

[0018] <2.3>Method for forming nonwoven fabric into a sheet The needle punching method is used to form sheets from aggregates of animal hair fibers, etc. By piercing a large number of animal hair fibers with numerous needles from both sides across the entire surface, the numerous animal hair fibers can be integrated, and both the surface 11a and back surface 11b of the nonwoven fabric body 11 become napped, improving the adhesion and germination of 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 become less likely to intertwine, making it difficult to form them into sheets. If the fiber length of the nonwoven fabric body 11 is greater than 80 mm, it inhibits the penetration of the nonwoven fabric body 11 by plant cotyledons, especially the cotyledons of dicotyledonous plants.

[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. Figure 4 shows a magnified view of animal hair fibers (wool) with a fiber width of 0.02 mm, and Figure 5 shows a magnified 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 become less likely to intertwine, making it difficult to form a sheet. If the fiber width of the nonwoven fabric body 11 is greater than 0.06 mm, it will inhibit the penetration of the nonwoven fabric body 11 by plant cotyledons, especially the cotyledons of dicotyledonous plants.

[0022] <2.6> Meat size The basis weight (weight per unit area) of the nonwoven fabric constituting the nonwoven fabric body 11 is 40-150 g / m². 2 A range of this magnitude is desirable. Figure 4 shows a basis weight of 50g / m². 2 Figure 5 shows the nonwoven fabric body 11, with a basis weight of 100 g / m². 3 This shows the nonwoven fabric body 11.

[0023] Nonwoven fabric with a basis weight of 40g / m² 2 If the size is smaller, unevenness in weight distribution is more likely to occur during the manufacturing of the nonwoven fabric body 11. Unevenness in the distribution of the material can easily lead to inconsistencies in erosion prevention and vegetation growth, and also prevent the full fertilizing effect of the biodegradable fibers from being obtained. Nonwoven fabric with a basis weight of 150g / m² 3 If the shade is too large, the shading effect will be stronger, worsening the conditions for plant germination.

[0024] <2.7> Penetration resistance (puncture strength) of the nonwoven fabric itself To ensure that even dicotyledonous plants with non-pointed cotyledon tips can quickly penetrate the nonwoven fabric body 11, the optimal penetration resistance (puncture strength) of the nonwoven fabric body 11 was tested. The puncture strength test is a test conducted in accordance with JIS Z 1707 "General Rules for Plastic Films for Food Use," and measures the force required to create a hole in the nonwoven fabric body 11 when 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, as determined by the puncture strength test, should be 0.3N or less, and preferably 0.03N or more. If the penetration resistance of the nonwoven fabric body 11, as determined by a puncture strength test, exceeds 0.3N, the penetration resistance of the nonwoven fabric body 11 increases, inhibiting penetration of the nonwoven fabric body 11 by plant cotyledons, especially those of dicotyledonous plants. When the penetration resistance of the nonwoven fabric body 11, as determined by a puncture strength test, falls below 0.03 N, the ability to capture soil particles decreases, and the erosion suppression effect of the vegetation sheet 10 deteriorates.

[0026] In Newton's units, a larger value indicates greater strength, and a smaller value indicates weaker strength. <3> Plant seeds that can be introduced The plant seeds 12 that can be attached to the nonwoven fabric body 11 can be a mixture of one or both dicotyledonous plants and monocotyledonous plants. The reasons why dicotyledonous plants can be introduced will be explained later.

[0027] From the perspective of biodiversity conservation, it is desirable to use seeds of native Japanese plants whenever possible. As plant seeds 12, various types of seeds can be introduced, including not only monocotyledonous plants but also dicotyledonous plants, thus expanding the range of plants that can be used for greening with the vegetation sheet 10.

[0028] <3.1>Dicotyledonous plants As for dicotyledonous plants, it is possible to use any one or a combination of the following examples of plants. ● Leguminous plants (Lespedeza bicolor, Lespedeza thunbergii, etc.) ● Plants of the Asteraceae family (such as mugwort) ● Leguminous plants (such as Vicia cracca, Vicia hirsuta, etc.) ● Polygonaceae plants (such as dock, Japanese dock, and sorrel) ● Anacardiaceae plants (such as Rhus javanica and Trichosanthes ursinus) ● Oleaceae plants (lilac, dwarf lilac, sweet osmanthus, etc.) ● Euphorbiaceae plants (plants belonging to genera such as Euphorbia, Celtis sinensis, and Indigofera japonica) ● Elaeagnaceae plants (Elaeagnus multiflora, Elaeagnus umbellata etc.) ● Rosaceae plants ●Ericaceae plants

[0029] Furthermore, as for dicotyledonous plants, any one or a combination of the following species can be used: Brassica juncea, Crepis japonica, Erigeron annuus, Thistle, Solanum nigrum, Macleaya cordata, Viola grypoceras, Lactuca indica, Sow thistle, Gnaphalium affine, Potentilla fragarioides, Chickweed, and Phytolacca americana.

[0030] <3.2> Monocotyledonous plants As monocotyledonous plants, known seeds of grasses (such as crabgrass, foxtail grass, goosegrass, annual bluegrass, and maize), Commelinaceae plants (such as dayflower, gentian, and Japanese ginger), and Miscanthus genus plants (such as silk grass, Japanese cedar, and striped cedar) can be used.

[0031] <4> fertilizer The fertilizer 13 attached to the nonwoven fabric body 11 can be of any type (chemical fertilizer, organic fertilizer) as long as it is a type commonly used as plant fertilizer. For fertilizer 13, for example, nitrogen-based fertilizer (G), phosphorus-based fertilizer (P), and potassium-based fertilizer (K) are used in appropriate proportions. In this invention, the nonwoven fabric body 11 functions as a slow-release fertilizer, thereby reducing the amount of fertilizer 13 that adheres to it.

[0032] <5> Reinforcement net The reinforcing net 15 can be made of biodegradable (nets made of plant fibers such as hemp twine), resin (chemical nets), or metal (wire mesh) netting. The mesh size of the reinforcing net 15 is designed so as not to adversely affect plant germination and growth. Biodegradable plant fiber materials can include, for example, hemp and coconut fiber, as well as animal hair fibers. In this example, we will describe a configuration in which a hemp mesh material is attached to one side of the nonwoven fabric body 11 as a reinforcing net 15.

[0033] By laminating a 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 it is installed on slopes, etc.

[0034] [Slope protection method using vegetation sheets] This section describes a slope protection method using vegetation sheets 10.

[0035] <1> Installation of vegetation sheets After removing weeds, trees, and loose stones from the slope, lay vegetation sheets 10 on the slope. When laying the vegetation sheet 10, the back side 11b of the vegetation sheet 10 is unfolded facing the slope, and fixing pins such as anchor pins or bamboo skewers are driven into multiple places on the vegetation sheet 10 to secure it.

[0036] <2> Plant germination environment By limiting the dimensions and basis weight of the animal hair fibers that make up the nonwoven fabric body 11 to a specific range, sunlight can enter the back side of the vegetation sheet 10, creating a favorable environment for the germination of plant seeds 12.

[0037] <3> Elongation of cotyledons in plant seeds The germinated cotyledons of the plant seeds 12 penetrate between the animal hair fibers of the nonwoven fabric body 11 that makes up the vegetation sheet 10, then penetrate the surface side, and then extend to the ground surface by passing through the mesh of the reinforcing net 15.

[0038] In particular, since the animal hair fibers of the nonwoven fabric body 11 are only intertwined with each other in a state where the animal hair fibers can move, the gaps formed between the animal hair fibers can be widened or narrowed in accordance with the displacement of each animal hair fiber. Therefore, the cotyledons of the plant seeds 12 grow upward, pushing aside the animal hair fibers of the nonwoven fabric body 11 and expanding the gaps.

[0039] Therefore, even if the plant seed 12 is from a dicotyledonous plant, it can penetrate the vegetation sheet 10 and germinate. If the plant seed 12 is from a monocotyledonous plant, the cotyledons will penetrate the vegetation sheet 10 more easily.

[0040] <4> Plant growth environment after germination In the vegetation sheet 10 according to the present invention, when plant seeds 12 germinate, the fertilizer 13 attached to the vegetation sheet 10 functions and releases fertilizer components. In other words, when the plant seeds 12 germinate, the biodegradable nonwoven fabric body 11 has not yet fully decomposed into fertilizer, so the fertilizer 13 is the main component that releases fertilizer components.

[0041] The animal hair fibers, which are the main raw material of the nonwoven fabric body 11, contain a large amount of protein, and when the animal hair fibers biodegrade in the soil, nitrogen (N) is released and they are converted into fertilizer. Thus, the biodegradable animal hair fibers that make up the nonwoven fabric body 11 gradually decompose 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 stops releasing its fertilizer components early on, but the nonwoven fabric body 11, which contains biodegradable fiber components, continues to release small amounts of fertilizer components over several months. As the nonwoven fabric body 11 undergoes biodegradation over a long period, the nonwoven fabric body 11 functions as a slow-release fertilizer.

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

[0044] <5> Various effects of vegetation sheets As described above, the vegetation sheet 10 according to the present invention not only acts as fertilizer, but also exhibits several other effects as described below.

[0045] <5.1> Effect of suppressing topsoil erosion on slopes The vegetation sheet 10 according to the present invention is configured such that the dimensions and basis weight of the animal hair fibers used as the main raw material can suppress the erosion of topsoil on the slope. Therefore, the vegetation sheet 10 presses down on the entire slope to be greened, exhibiting a high erosion prevention effect.

[0046] <5.2> Regulating effect of soil temperature The animal hair fibers, which are the main raw material of the vegetation sheet 10 of the present invention, contain a lot of air and have excellent heat insulation properties. Furthermore, animal hair fibers are known to generate heat when they absorb moisture. These features prevent soil freezing in winter and raise soil temperature during low temperatures in spring and autumn, thus maintaining a favorable growing environment for introduced plants throughout the year.

[0047] <5.3> Repellent effect of wild animals The main raw material of the vegetation sheet 10 of the present invention contains animal hair fibers. If the animal hair fiber is wool, then wool has a distinctive odor. The distinctive scent of wool acts as a repellent against wild animals such as deer and wild boars. Therefore, by preventing wild animals from entering areas that have been greened with vegetation sheets, it is possible to effectively avoid damage from grazing and slope destruction caused by wild animals. [Explanation of Symbols]

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

Claims

1. A biodegradable vegetation sheet comprising a nonwoven fabric body formed into a sheet by intertwining biodegradable fibers, with plant seeds and fertilizer attached to the back surface, The aforementioned nonwoven fabric body is mainly made from animal hair fibers with keratin as the main component, The nonwoven fabric is characterized by being formed into a sheet by intertwining animal hair fibers using a needle punching method, while possessing slope erosion prevention and fertilizing properties, and enabling plant seed germination. Biodegradable vegetation sheet.

2. The sheet thickness of the aforementioned nonwoven fabric body is 0.5 to 2 mm. The nonwoven fabric body is characterized by having a puncture strength of 0.03 to 0.3 N. The biodegradable vegetation sheet according to claim 1.

3. The fiber length of the aforementioned animal hair fibers is 20 to 80 mm. The fiber width of the aforementioned animal hair fiber is 0.02 to 0.06 mm. The basis weight of the aforementioned animal hair fibers is 40 to 150 g / m ２ It is characterized by being, The biodegradable vegetation sheet according to claim 1 or 2.

4. The biodegradable vegetation sheet according to claim 1 or 2, characterized in that the animal hair fibers include one or more of the following: wool, mohair, cashmere, camel, alpaca, llama, Angora rabbit, etc.

5. The biodegradable vegetation sheet according to claim 1, characterized in that the nonwoven fabric body contains biodegradable cotton or rayon.

6. The biodegradable vegetation sheet according to claim 1, characterized in that a biodegradable reinforcing net is attached to the surface of the nonwoven fabric body.

7. The biodegradable vegetation sheet according to claim 6, characterized in that the mesh size of the reinforcing net has a mesh size that allows plant seeds to germinate and grow.

8. The biodegradable vegetation sheet according to claim 6, characterized in that the plant seeds include at least dicotyledonous plants.

Images