Sunshade net for matcha planting root system light control and preparation method

Abstract

The invention relates to the technical field of sunshade nets, and discloses a sunshade net for matcha planting root system light control and a preparation method. The sunshade net is characterized in that the sunshade net is formed by weaving blue ribbon-like filaments and silver ribbon-like filaments in an alternate distribution mode, the blue ribbon-like filaments are matched with high-refractive-index and low-refractive-index fillers, the blue ribbon-like filaments have optical non-uniformity, blue light can softly penetrate through the blue ribbon-like filaments, and therefore the blue ribbon-like filaments can form good scattering to irradiate leaves and roots of a tea tree. A good blue light quality environment is constructed for the tea leaves, and the formation of amino acids and nitrogen-containing aromatic substances in the tea leaves is promoted; the silver flat filaments have good light reflection performance, so that the transmission of ultraviolet rays is reduced, the influence of high temperature caused by directly covering the tea tent with the sunshade net is avoided, and the generation of tea polyphenol with bitter taste is reduced, so that the quality requirement of the matcha is met. The sunshade net is suitable for precise light control in a tea garden field and direct covering shading of a canopy surface, the effect of improving the quality of matcha is remarkable, and large-scale production and use can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of sunshade nets, and particularly to a sunshade net for controlling light on the roots of matcha tea plants and a preparation method thereof. Background Art

[0002] Matcha is a micro-powdered tea product made from fresh tea leaves of tea plants cultivated under covering, through hot air fixation, drying, and grinding processes. With the popularization of tea-containing foods, the demand for matcha has increased rapidly. Since matcha is often compounded with traditional food industrial raw materials, it is required that the flavor characteristics of the tea are prominent and stable. This poses higher requirements for the cultivation technology of directional regulation of stable tea quality.

[0003] Tea plants belong to light-loving plants, but the requirements for light by tea plants are neither too strong nor too weak, and they prefer scattered light rather than direct strong sunlight. Direct strong sunlight will cause damage to tea plants. Especially in summer, high temperature and strong light will promote the generation of tea polyphenols, such as the large generation of bitter-tasting substances flavonol glycosides, which will increase the bitterness of the tea leaves and greatly limit the use of matcha raw materials. In addition, the light quality environment is extremely crucial for the formation of tea quality components. According to existing research, blue and violet light can well promote the formation of tea amino acids, proteins, and nitrogen-containing aromatic substances, and the content of tea polyphenols is small, which is very beneficial to the formation of tea quality and is suitable for use as matcha raw materials.

[0004] The shading and covering cultivation technology can significantly change the components of tea leaves. Currently, the black sunshade net covering technology is usually used to cultivate matcha. By reducing direct sunlight and increasing diffused light, the chlorophyll content of the tea leaves is greatly increased, the bitterness of the tea leaves is reduced, and the freshness is improved. However, at the same time as shading, the transmission of blue light is also weakened, which limits the improvement of tea quality components.

[0005] On the other hand, most of the existing tea plant covering treatment technologies adopt the traditional method of setting up brackets and covering with a shed. This method is not conducive to the full mechanization operation of the tea garden, affects production efficiency, and the large-scale setting up of brackets in the tea garden requires a huge investment. Covering and removing the net consume a lot of labor, increasing the management and maintenance costs. Therefore, the direct covering mode on the tea canopy is the main development direction of future tea garden covering treatment. The direct covering on the tea canopy helps to realize the full mechanization operation of the tea garden, as well as the use and promotion of riding-type tea picking machines.

[0006] However, the widely used black sunshade nets at present are easy to absorb heat. If directly covered on the tea canopy, it can cause the tea plants to be in a high-temperature environment, not only easily resulting in the phenomenon of bud leaves being burned by high temperature, affecting the growth and quality of tea shoots. Moreover, when the tea plants are in a high-temperature environment, the water in the roots is easily evaporated. Summary of the Invention

[0007] To reduce the impact of strong ultraviolet rays on the quality of tea leaves, increase the biomass of tea plants, and solve the problem that the current black sunshade net used for directly covering the tea canopy surface is prone to causing bud and leaf burns and affecting the quality of fresh leaves, the present invention provides a sunshade net for controlling light on the root system of matcha tea cultivation and a preparation method. By preparing a sunshade net with blue flat filaments and silver flat filaments distributed alternately, the penetration of ultraviolet light can be effectively prevented, and the penetration of blue light can be increased, creating a cool growth environment for tea plants. This not only helps the growth of tea plants but also significantly improves the quality of tea leaves to meet the quality requirements of matcha tea.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A sunshade net for controlling light on the root system of matcha tea cultivation, characterized in that the sunshade net is composed of blue flat filaments and silver flat filaments distributed alternately and is fixed by knitting lines evenly distributed along the length direction of the flat filament strips; wherein:

[0010] The width of the blue flat filament is 5 - 8 mm and the thickness is 40 - 60 μm. It is obtained by hot melt extrusion, casting into a film, slicing with a blade, and hot stretching from high-density polyethylene, a dispersant, titanium dioxide, magnesium fluoride, and blue pigment powder.

[0011] The width of the silver flat filament is 5 - 8 mm and the thickness is 60 - 100 μm. It is obtained by hot melt extrusion, casting into a film, slicing with a blade, and hot stretching from high-density polyethylene, a dispersant, glass microspheres, zinc sulfide, and carbon black.

[0012] Preferably, the light-shielding rate of the sunshade net is 70 - 85%.

[0013] Preferably, the blue flat filament is prepared from high-density polyethylene, a dispersant, titanium dioxide, magnesium fluoride, and blue pigment powder according to the mass ratio of (90 - 95):(2 - 3):(0.5 - 1.0):(0.5 - 1.0):(0.05 - 0.08).

[0014] Preferably, the particle size distribution of the titanium dioxide D80 is 0.1 - 0.5 μm.

[0015] Preferably, the particle size distribution of the magnesium fluoride D90 is 1 - 2 μm.

[0016] Preferably, the blue pigment powder selects at least one of Pigment Blue 60 (CAS No.: 81 - 77 - 6), Pigment Blue 15:2 (CAS No.: 12239 - 87 - 1), and Pigment Blue 15 (CAS No.: 147 - 14 - 8).

[0017] The blue flat filaments have good blue light transmittance and ultraviolet blocking properties. At the same time, titanium dioxide has a relatively high refractive index. The refractive index of rutile titanium dioxide is 2.76, and that of anatase titanium dioxide is 2.55; magnesium fluoride has a relatively low refractive index of 1.38; the refractive index of high-density polyethylene is about 1.52; by using fillers with different refractive indices in the blue flat filaments, the blue flat filaments have optical inhomogeneity, and when light passes through, the light undergoes multiple refractions, thus forming good scattering.

[0018] Preferably, the silver flat filaments are prepared from high-density polyethylene, dispersant, glass microspheres, zinc sulfide, and carbon black according to the mass ratio of (90 - 95):(2 - 3):(1 - 2):(1 - 2):(0.2 - 0.3).

[0019] Preferably, the particle size of the glass microspheres is 10 - 50 μm, and the sphericity ≥ 85%; it not only has good high dispersion and fluidity, but also its spherical shape enhances the light reflection effect of the silver flat filaments.

[0020] Preferably, the particle size distribution of the zinc sulfide D50 is 0.3 - 0.5 μm. Zinc sulfide has a high refractive index, with a refractive index of 2.35 - 2.37 and good gloss, which makes the silver flat filaments produce a significant light reflection effect on the surface, enabling the sunshade net to have the performance of reflecting light and reducing temperature.

[0021] The silver flat filaments utilize the combination of glass microspheres, zinc sulfide, and carbon black to form a silver surface, having good light reflection performance and reducing the transmittance of ultraviolet rays.

[0022] Preferably, the dispersant is selected from at least one of polyethylene wax, stearic acid, ethylene bisstearamide, ethylene bisoleamide, and zinc stearate; its main function is to increase the dispersibility of each pigment and the hot flow processing performance of high-density polyethylene. It reduces the carbon deposition at the T-shaped extrusion die orifice and improves the surface gloss of the flat filaments.

[0023] Furthermore, the present invention provides a preparation method for a sunshade net for controlling light on the root system of matcha cultivation, specifically including the following steps:

[0024] S1. Prepare blue flat filaments: Mix high-density polyethylene, dispersant, titanium dioxide, magnesium fluoride, and blue pigment powder evenly in a color mixer according to the mass ratio of (90 - 95):(2 - 3):(0.5 - 1.0):(0.5 - 1.0):(0.05 - 0.08), send it to a twin-screw extruder for hot melt mixing, extrude it into a sheet-like melt through a T-shaped die orifice; the sheet-like melt is cast onto a roller, pre-stretched and cooled by rotating multiple groups of rollers to form a film, the film is cut into flat filament embryos by a filament cutting tool holder, and further preheated and traction-stretched by rollers, and then wound into a filament ingot by a wire winding machine to obtain blue flat filaments;

[0025] S2. Prepare silver flat filaments: Mix high-density polyethylene, dispersant, glass microspheres, zinc sulfide, and carbon black evenly in a color mixer according to the mass ratio of (90 - 95):(2 - 3):(1 - 2):(1 - 2):(0.2 - 0.3), send it to a twin-screw extruder for hot melt mixing and extrusion, and extrude it into a sheet-like melt through a T-shaped die; the sheet-like melt is cast onto a roller, pre-stretched and cooled by the rotation of multiple groups of rollers to form a film, the film is cut into flat filament embryos by a filament cutting tool holder, further preheated by a roller and traction stretched, and wound into a filament ingot by a winding machine to obtain silver flat filaments;

[0026] S3. Interlace the blue flat filaments and the silver flat filaments through a wire mesh weaving machine, and fix them by weaving with weaving wires evenly distributed along the length direction of the flat filament strips to form a plain weave mesh; arrange dense weaving wires inside the inner side of the mesh edge to form a connection strengthening part; turn the mesh edge inward and lock the edge to form an edge fixing part, and wind it to obtain a sunshade net for controlling light for the root system of matcha cultivation.

[0027] Preferably, the twin-screw extruder is an SHJ-75 type twin-screw extruder with a screw diameter of 75 mm, and the temperature control of each heating zone is: zone 1: 160 - 180 °C; zone 2: 190 - 200 °C; zone 3: 210 - 220 °C; zone 4: 210 - 220 °C; zone 5: 220 - 230 °C; T-shaped die: 210 - 220 °C.

[0028] Preferably, the roller preheating is carried out at a temperature of 100 - 120 °C; the stretching ratio of the traction stretching is controlled within 3 - 8 times; the linear speed of the traction stretching is ≥ 300 m / min. By controlling the stretching ratio, the width of the blue flat filaments is controlled to be 5 - 8 mm and the thickness is 40 - 60 μm; the width of the silver flat filaments is 5 - 8 mm and the thickness is 60 - 100 μm. Through high-speed stretching, the molecular chains of high-density polyethylene (HDPE) will be oriented along the stretching direction, increasing the tensile strength of the flat filaments.

[0029] Preferably, when weaving the plain weave mesh, the spacing of the evenly distributed weaving wires is controlled within 5 - 8 cm; dense weaving wires are arranged inside the inner side of the mesh edge, and the spacing of the dense weaving wires is 1 - 1.5 cm.

[0030] The present invention increases the blue light selective transmittance and scattering of the blue flat filaments; enhances the light reflection of the silver flat filaments; uses the sunshade net woven by the interlaced distribution of the blue flat filaments and the silver flat filaments to avoid the high temperature generated by directly covering the tea canopy with the sunshade net, which affects the growth of new leaf shoots, changes the light quality environment, reduces the temperature of the leaf surface and the root system, enhances the root coolness, reduces the content of tea polyphenols, improves the amino acid level of the tea leaves, reduces the phenolic ammonia ratio of the tea leaves, and improves the tea quality.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. The present invention effectively reflects ultraviolet light and selectively transmits blue light by preparing a sunshade net with blue flat filaments and silver flat filaments distributed alternately.

[0033] 2. The blue flat filaments of the sunshade net of the present invention are combined with high and low refractive index fillers, making the blue flat filaments optically inhomogeneous. While having good blue light transmittance, it promotes multiple refractions of light, can gently transmit blue light, and thus forms good scattered illumination on the leaves and roots of tea plants, constructs a good blue light quality environment for tea leaves, promotes the formation of amino acids and nitrogen-containing aromatic substances in tea leaves, and significantly improves the quality of tea leaves.

[0034] 3. The sunshade net of the present invention uses silver flat filaments, which have good light reflection performance, reduce the transmittance of ultraviolet rays, avoid the high temperature generated by directly covering the tea canopy with the sunshade net from affecting the growth of new leaf shoots, create a cool growth environment for the roots of tea plants, and reduce the generation of bitter-tasting tea polyphenols to meet the quality requirements of matcha.

[0035] 4. The sunshade net of the present invention is suitable for precise light control in tea gardens and direct covering of the canopy for shading. It has a significant effect on improving the quality of matcha and can be produced and used on a large scale. Description of the Drawings

[0036] Figure 1 It is a schematic diagram of a sunshade net for controlling light of the root system in matcha cultivation according to the present invention. Explanation of the reference numerals: 1 - blue flat filament; 2 - silver flat filament; 3 - knitting thread; 4 - edge locking.

[0037] Figure 2 It is a physical photo of the sunshade net for controlling light of the root system in matcha cultivation obtained in Example 1. Detailed Embodiments

[0038] To make the technical solutions and advantages of the present invention clearer, the present invention is further described in detail, including the detailed illustration clearly shown by the drawings. The described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the common knowledge in the art, the raw materials, equipment, and processes that are not clearly defined are the conventional technologies that can be understood by those of ordinary skill in the art.

[0039] Example 1

[0040] S1. Prepare blue flat filaments: Weigh 95 kg of high-density polyethylene (Braskem PE SHE150, Braskem, Brazil), 2.5 kg of polyethylene wax, 1.0 kg of titanium dioxide (rutile type, D80 particle size distribution of 0.1 - 0.5 μm), 0.8 kg of magnesium fluoride (D90 particle size distribution of 1 - 2 μm), and 0.06 kg of Pigment Blue 60. Mix them evenly in a color mixer and send them to an SHJ-75 twin-screw extruder. The temperature control of each heating zone is as follows: Zone 1: 180 °C; Zone 2: 190 °C; Zone 3: 210 °C; Zone 4: 220 °C; Zone 5: 230 °C; T-die: 220 °C. After hot melt mixing and extrusion, a sheet-like melt is extruded at the T-die. The sheet-like melt is cast onto a roller and pre-stretched and cooled by the rotation of multiple rollers to form a film. The film is cut into flat filament embryos by a filament splitting knife rest, further preheated to 115 °C by a roller, the linear speed of traction and stretching is adjusted to 400 m / min, the stretching ratio is controlled at 6 times, and the winding machine winds it into a filament ingot to obtain blue flat filaments with a width of 5 mm and a thickness of 60 μm;

[0041] S2. Prepare silver flat filaments: Weigh 91 kg of high-density polyethylene (Braskem PE SHE150, Braskem, Brazil), 2 kg of ethylene bisoleamide, 1.5 kg of glass microspheres (particle size of 10 - 50 μm, sphericity ≥ 85%), 1.5 kg of zinc sulfide (Sachtolith HD-S, average particle size of 0.3 μm, Sachtleben, Germany), and 0.25 kg of carbon black (660R, Cabot). First, mix the glass microspheres, zinc sulfide, and carbon black with ethylene bisoleamide evenly, and then mix them evenly with high-density polyethylene in a color mixer and send them to an SHJ-75 twin-screw extruder. The temperature control of each heating zone is as follows: Zone 1: 180 °C; Zone 2: 190 °C; Zone 3: 210 °C; Zone 4: 220 °C; Zone 5: 230 °C; T-die: 220 °C. After hot melt mixing and extrusion, a sheet-like melt is extruded at the T-die. The sheet-like melt is cast onto a roller and pre-stretched and cooled by the rotation of multiple rollers to form a film. The film is cut into flat filament embryos by a filament splitting knife rest, further preheated to 110 °C by a roller, the linear speed of traction and stretching is adjusted to 300 m / min, the stretching ratio is controlled at 4 times, and the winding machine winds it into a filament ingot to obtain silver flat filaments with a width of 7 mm and a thickness of 80 μm;

[0042] S3. Intersperse the blue flat filaments and the silver flat filaments through a weaving machine and fix them by weaving with weaving threads evenly distributed along the length direction of the flat filament strips to form a plain weave net. The spacing of the weaving threads is controlled at 5 cm. Dense weaving threads are arranged on the inner side of the net edge, with a spacing of 1 cm for the dense weaving threads to form a connection strengthening part. After folding the net edge inward and hemming, an edge fixing part is formed, and it is wound to obtain a sunshade net for controlling light for the root system of matcha cultivation.

[0043] As attached Figure 1Schematic diagram of a sunshade net for controlling light on the root system of matcha tea plants. It is formed by arranging blue flat filaments (1) and silver flat filaments (2) alternately and fixing them by knitting with knitting threads (3) to form a plain stitch net. Dense knitting threads are arranged on the inner side of the net edge, with a spacing of 1 cm between the dense knitting threads to form a connection strengthening part. After folding inward at the net edge, a hemming (4) is formed.

[0044] As shown in the appendix Figure 2 The physical photo of the sunshade net for controlling light on the root system of matcha tea plants obtained.

[0045] Example 2

[0046] S1. Prepare blue flat filaments: Weigh 95 kg of high-density polyethylene (Braskem PE SHE150, Braskem, Brazil), 2 kg of stearic acid, 0.5 kg of titanium dioxide (anatase type, with a particle size distribution of D80 being 0.3 - 0.5 μm), 0.5 kg of magnesium fluoride (with a particle size distribution of D90 being 1 - 2 μm), and 0.08 kg of Pigment Blue 15:2. Stir them evenly in a color mixer and send them to an SHJ-75 type twin-screw extruder. The temperature control of each heating zone is as follows: Zone 1: 160 °C; Zone 2: 190 °C; Zone 3: 210 °C; Zone 4: 220 °C; Zone 5: 230 °C; T-shaped die: 210 °C. After hot melt mixing and extrusion, the sheet-like melt is extruded through the T-shaped die. The sheet-like melt is cast onto a roller, pre-stretched and cooled by rotating multiple groups of rollers to form a film. The film is cut into flat filament embryos by a filament cutting tool rest, and then preheated to 120 °C by a roller. The linear speed of traction and stretching is adjusted to 450 m / min, and the stretching ratio is controlled at 7 times. The winding machine winds it into a filament bobbin to obtain blue flat filaments with a width of 5 mm and a thickness of 50 μm.

[0047] S2. Prepare silver flat filaments: Weigh 90 kg of high-density polyethylene (Braskem PE SHE150, Braskem, Brazil), 2 kg of ethylene bis-stearamide, 2.0 kg of glass microspheres (particle size 10 - 50 μm, sphericity ≥ 85%), 1.5 kg of zinc sulfide (Sachtolith HD-S, average particle size 0.3 μm, Sachtleben, Germany), and 0.2 kg of carbon black (660R, Cabot); first, add the glass microspheres, zinc sulfide, and carbon black to the ethylene bis-stearamide and mix evenly, then mix evenly with the high-density polyethylene in a color mixer, and send it to an SHJ-75 type twin-screw extruder. The temperature control of each heating zone is as follows: zone 1 at 180 °C; zone 2 at 200 °C; zone 3 at 220 °C; zone 4 at 220 °C; zone 5 at 230 °C; the T-shaped die orifice at 220 °C; after hot melt mixing and extrusion, extrude into a sheet-like melt through the T-shaped die orifice; the sheet-like melt is cast onto a roller, and through multiple groups of rotating rollers for pre-stretching and cooling to form a film. The film is cut into flat filament embryos by a filament cutting tool rest, further preheated to 100 °C by a roller, the linear speed of traction and stretching is adjusted to 300 m / min, the stretching ratio is controlled at 4 times, and the winding machine winds it into a filament ingot to obtain silver flat filaments with a width of 6 mm and a thickness of 85 μm;

[0048] S3. Interlace the blue flat filaments and the silver flat filaments through a wire weaving machine, and fix them by weaving with weaving wires evenly distributed along the length direction of the flat filament strips to form a plain weave net. The spacing of the weaving wires is controlled at 6 cm; set dense weaving wires inside the net edge, and the spacing of the dense weaving wires is 1.5 cm to form a connection strengthening part; turn the net edge inward and lock the edge to form an edge fixing part, and wind it to obtain a sunshade net for controlling light for the root system of matcha cultivation.

[0049] Example 3

[0050] S1. Prepare blue flat filaments: Weigh 90 kg of high-density polyethylene (Braskem PE SHE150, Braskem, Brazil), 2 kg of stearic acid, 1 kg of titanium dioxide (anatase type, D80 particle size distribution 0.3 - 0.5 μm), 1 kg of magnesium fluoride (D90 particle size distribution 1 - 2 μm), and 0.06 kg of pigment blue 15:2, mix evenly in a color mixer, and send it to an SHJ-75 type twin-screw extruder. The temperature control of each heating zone is as follows: zone 1 at 160 °C; zone 2 at 190 °C; zone 3 at 210 °C; zone 4 at 220 °C; zone 5 at 230 °C; the T-shaped die orifice at 210 °C; after hot melt mixing and extrusion, extrude into a sheet-like melt through the T-shaped die orifice; the sheet-like melt is cast onto a roller, and through multiple groups of rotating rollers for pre-stretching and cooling to form a film. The film is cut into flat filament embryos by a filament cutting tool rest, further preheated to 120 °C by a roller, the linear speed of traction and stretching is adjusted to 450 m / min, the stretching ratio is controlled at 6 times, and the winding machine winds it into a filament ingot to obtain blue flat filaments with a width of 6 mm and a thickness of 60 μm;

[0051] S2. Prepare silver flat filaments: Weigh 90 kg of high-density polyethylene (Braskem PE SHE150, Braskem, Brazil), 2 kg of ethylene bisstearamide, 2.0 kg of glass microspheres (particle size 10 - 50 μm, sphericity ≥ 85%), 2 kg of zinc sulfide (Sachtolith HD-S, average particle size 0.3 μm, Sachtleben, Germany), and 0.3 kg of carbon black (660R, Cabot); first, add the glass microspheres, zinc sulfide, and carbon black to the ethylene bisstearamide and mix evenly, then mix evenly with the high-density polyethylene in a color mixer, and send it to an SHJ-75 type twin-screw extruder. The temperature control of each heating zone is as follows: zone 1 is 180 °C; zone 2 is 200 °C; zone 3 is 220 °C; zone 4 is 220 °C; zone 5 is 230 °C; the T-shaped die is 220 °C; after hot melt mixing and extrusion, it is extruded into a sheet-like melt through the T-shaped die; the sheet-like melt is cast onto a roller, and pre-stretched and cooled by the rotation of multiple groups of rollers to form a film. The film is slit into flat filament embryos by a slitting tool holder, further preheated to 100 °C by a roller, the linear speed of traction and stretching is adjusted to 300 m / min, the stretching ratio is controlled at 3 times, and the winding machine winds it into a silk ingot to obtain silver flat filaments with a width of 6 mm and a thickness of 100 μm;

[0052] S3. Intersperse the blue flat filaments and the silver flat filaments through a wire mesh weaving machine, and fix them by weaving with weaving wires evenly distributed along the length direction of the flat filament strips to form a plain weave mesh. The spacing of the weaving wires is controlled at 8 cm; set dense weaving wires inside the mesh edge, and the spacing of the dense weaving wires is 1.5 cm to form a connection strengthening part; turn the mesh edge inward and lock the edge to form an edge fixing part, and wind it to obtain a sunshade net for controlling light for the root system of matcha cultivation.

[0053] Use the sunshade nets of Examples 1 - 3 and a commercially available 3-needle black sunshade net with a light shading rate of 70% for shade cultivation of Longjing 43# in Zhejiang region. In early summer, when the bud leaves grow to one bud and two leaves, directly cover the tea canopy with the sunshade net for shading. After covering for 25 days, pick, kill the green and dry it for detecting the content of quality components. Refer to "GB / T 8313 Detection Method for the Content of Tea Polyphenols and Catechins" to detect the tea polyphenol content of the tea. Refer to "GB / T 8314 Determination of Total Free Amino Acids in Tea" to detect the free amino acid content of the tea. By comparing with the reference sample without using the sunshade net, qualitatively analyze the change of the phenolic ammonia ratio, as shown in Table 1.

[0054] Table 1: Detection of Tea Polyphenol Content, Free Amino Acid Content, and Phenolic Ammonia Ratio

[0055]

[0056] Through qualitative analysis of test data, the blue-silver shading net of the present invention makes full use of the transmittance and scattering property of blue light to inhibit the synthesis of tea polyphenols and promote the accumulation of free amino acids. At the same time, the silver reflection cools down to avoid the influence of ultraviolet rays and high temperature on tea leaves. When directly covering the tea canopy for shading treatment, compared with the traditional black net, it can better maintain the reasonable temperature and light quality environment of the tea tree, promote the generation of amino acids, control the content of tea polyphenols, maintain a lower ratio of phenol to ammonia, and the fresh taste of the made tea is good while the bitter taste is reduced, thus meeting the quality requirements of matcha tea.

[0057] The above describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. What is described in the above embodiments and the specification only illustrates the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed.

Claims

1. A sunshade net for controlling light on the root system of matcha tea planting, characterized in that, The sunshade net is formed by alternately distributing blue flat filaments and silver flat filaments, and is fixed by weaving with weaving threads evenly distributed along the length direction of the flat filament strips; wherein: The blue flat filaments have a width of 5-8 mm and a thickness of 40-60 μm, and are obtained by hot-melting, extruding, casting into a film, slicing with a blade, and thermally stretching high-density polyethylene, a dispersant, titanium dioxide, magnesium fluoride, and blue pigment powder; The silver flat filaments have a width of 5-8 mm and a thickness of 60-100 μm, and are obtained by hot-melting, extruding, casting into a film, slicing with a blade, and thermally stretching high-density polyethylene, a dispersant, glass microspheres, zinc sulfide, and carbon black; 2. The sunshade net for controlling light on the root system of matcha planting according to claim 1, characterized in that, The light-shielding rate of the sunshade net is 70-85%; 3. The sunshade net for controlling light on the root system of matcha planting according to claim 1, characterized in that, The blue flat filaments are prepared from high-density polyethylene, a dispersant, titanium dioxide, magnesium fluoride, and blue pigment powder in a mass ratio of (90-95):(2-3):(0.5-1.0):(0.5-1.0):(0.05-0.08); 4. The sunshade net for controlling light of the root system in matcha planting according to claim 1, characterized in that, The particle size distribution of D80 of the titanium dioxide is 0.1-0.5 μm; the particle size distribution of D90 of the magnesium fluoride is 1-2 μm; 5. A sunshade net for controlling light on the root system of matcha planting according to claim 1, characterized in that, The blue pigment powder selects at least one of Pigment Blue 60, Pigment Blue 15:2, and Pigment Blue 15; 6. The sunshade net for controlling light on the root system of matcha planting according to claim 1, characterized in that, The silver flat filaments are prepared from high-density polyethylene, a dispersant, glass microspheres, zinc sulfide, and carbon black in a mass ratio of (90-95):(2-3):(1-2):(1-2):(0.2-0.3); 7. The sunshade net for controlling light on the root system of matcha planting according to claim 1, wherein The particle size of the glass microspheres is 10-50 μm, and the sphericity is ≥85%; the particle size distribution of D50 of the zinc sulfide is 0.3-0.5 μm; 8. The preparation method of the sunshade net for controlling light of the root system of matcha cultivation according to any one of claims 1-7 specifically includes the following steps: S1. Prepare blue flat filaments: Mix high-density polyethylene, a dispersant, titanium dioxide, magnesium fluoride, and blue pigment powder in a mass ratio of (90-95):(2-3):(0.5-1.0):(0.5-1.0):(0.05-0.08) evenly in a color mixer, send it to a twin-screw extruder for hot-melt mixing and extrusion, and extrude it into a sheet-like melt through a T-shaped die; the sheet-like melt is cast onto a roller, and is pre-stretched and cooled by rotating multiple groups of rollers to form a film. The film is cut into flat filament embryos by a wire-cutting knife rest, and further preheated by rollers, traction stretched, and wound into a wire ingot by a wire winding machine to obtain blue flat filaments; S2. Prepare silver flat filaments: Mix high-density polyethylene, a dispersant, glass microspheres, zinc sulfide, and carbon black in a mass ratio of (90-95):(2-3):(1-2):(1-2):(0.2-0.3) evenly in a color mixer, send it to a twin-screw extruder for hot-melt mixing and extrusion, and extrude it into a sheet-like melt through a T-shaped die; the sheet-like melt is cast onto a roller, and is pre-stretched and cooled by rotating multiple groups of rollers to form a film. The film is cut into flat filament embryos by a wire-cutting knife rest, and further preheated by rollers, traction stretched, and wound into a wire ingot by a wire winding machine to obtain silver flat filaments; S3. The blue flat filaments and the silver flat filaments are distributed alternately by a wire weaving machine, and are fixedly woven by knitting wires that are equally spaced along the length direction of the flat filament strips to form a plain stitch net; dense knitting wires are arranged inside the inner side of the net edge to form a connection strengthening part; the net edge is turned inwards and hemmed to form an edge fixing part, and then wound to obtain a sunshade net for controlling light for the root system of matcha planting.

9. The preparation method of the sunshade net for controlling light of the root system in matcha cultivation according to claim 8, characterized in that, The preheating of the roller is carried out at a temperature of 100-120 °C; the stretching ratio of the traction stretching is controlled at 3-8 times; the linear speed of the traction stretching is ≥300 m / min.

10. The preparation method of the sunshade net for controlling light of the root system of matcha tea planting according to claim 8, characterized in that, When weaving the plain stitch net, the spacing of the equally spaced knitting wires is controlled at 5-8 cm; dense knitting wires are arranged inside the inner side of the net edge, and the spacing of the dense knitting wires is 1-1.5 cm.

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