Liquid mulching film as well as preparation method and application thereof

Abstract

The invention discloses a liquid mulching film as well as a preparation method and application thereof. The liquid mulching film comprises 20-25 parts of polyvinyl alcohol; 10 to 13 parts of crushed straw; 15-20 parts of plant ash; 20 to 24 parts of xanthan gum; and 100 to 120 parts of water. The molecular weight of the polyvinyl alcohol is 170000-180000. The straw is corn straw, and the particle size of the crushed corn straw is 80-200mm; the plant ash is residues obtained after straw or rice straw is burnt, and the particle size of the plant ash is 0.5-2 mm; the viscosity of the xanthan gum is greater than or equal to 1200 mPa.s, and the ignition residue is 5.5-16.0; the liquid mulching film is sprayed on the surface of soil, and the mulching film is formed after natural air drying; the obtained mulching film is high in mechanical performance, good in water resistance, obvious in temperature increasing and entropy keeping, biodegradable, capable of being used for heat preservation and water resistance of soil, free of negative effects on physical and chemical properties of the soil and capable of increasing fertility of the soil after being degraded.

Description

Technical Field

[0001] The invention belongs to the technical field of composite materials, and in particular relates to a liquid ground film and a preparation method and application thereof. Background Art

[0002] Liquid mulch technology is an innovative agricultural covering technology, and its principle is mainly based on the three-dimensional cross-linked grid structure formed by the physical change of polymers. This structure can fill small holes and cracks in the ground, prevent water from invading the underground structure, and effectively prevent leakage. At the same time, the liquid mulch can form a solid waterproof barrier, which can not only prevent the base layer structure from being eroded by water, but also maintain waterproof performance for a long time.

[0003] Polyvinyl alcohol (PVA) is a water-soluble synthetic polymer with the molecular formula [CH2CH(OH)]n. Polyvinyl alcohol has some unique properties. It has good solubility in water, and the specific solubility depends on its degree of alcoholysis; Polyvinyl alcohol is thermally stable, with no obvious change below 40°C, but will gradually change color and become brittle when heated above 100°C; Polyvinyl alcohol is a crystalline atactic material, mainly composed of segments connected by 1,3-diol bonds, and has excellent film-forming, emulsifying and adhesive properties. These properties make polyvinyl alcohol widely used in liquid ground films.

[0004] Plastic mulch has multiple hazards to the environment and agricultural products. First, it is exposed to the soil for a long time and cannot be degraded, forming "white pollution" and increasing ground garbage. Second, plastic mulch affects the physical and chemical properties of the soil, causing soil compaction and reduced fertility, which in turn affects the root growth and yield of crops. In addition, plastic mulch may also release harmful substances, affecting the quality of agricultural products. Summary of the invention

[0005] In response to the above problems, the present invention provides a high-performance environmentally friendly liquid mulch film and a preparation method and application thereof. The resulting product has high mechanical properties, good water resistance, obvious warming and entropy retention, and is biodegradable. It not only does not have a negative impact on the physical and chemical properties of the soil, but can also increase the fertility of the soil after degradation.

[0006] In order to achieve the above purpose, the technical solutions adopted are as follows:

[0007] A liquid ground film, the composition of which is as follows by weight:

[0008] 20-25 parts of polyvinyl alcohol; 10-13 parts of crushed straw; 15-20 parts of wood ash; 20-24 parts of xanthan gum; 100-120 parts of water.

[0009] According to the above scheme, the molecular weight of the polyvinyl alcohol is 170,000-180,000.

[0010] According to the above scheme, the straw is corn straw, and the particle size after crushing is 80-200mm.

[0011] According to the above scheme, the wood ash is the residue after burning straw or rice straw, and the particle size is 0.5-2mm.

[0012] According to the above scheme, the viscosity of the xanthan gum is ≥1200 mPa·s, and the ignition residue is 5.5-16.0.

[0013] The method for preparing the liquid mulch film comprises the following steps:

[0014] The polyvinyl alcohol is mixed with water to prepare a polyvinyl alcohol solution; the straw crushed material, wood ash and xanthan gum are added in sequence and mixed and stirred to evenly disperse the materials and then let them stand to obtain a liquid mulch film.

[0015] The application of the liquid mulch film in agriculture includes spraying the liquid mulch film on the soil surface and forming the mulch film after natural air drying.

[0016] According to the above scheme, the spraying amount of the liquid mulch film on the soil surface is 80 to 100 L / mu.

[0017] A ground film is formed by spraying the above-mentioned liquid ground film on the soil surface and letting it dry naturally.

[0018] A soil heat preservation method comprises spraying the above-mentioned liquid ground film on the soil surface and naturally drying the ground film to cover the soil surface.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention uses polyvinyl alcohol as a raw material. The polyvinyl alcohol film has the characteristics of good density and high crystallinity, which makes it have good mechanical properties and barrier properties. Polyvinyl alcohol is also a biodegradable material, which can be decomposed into carbon dioxide and water by microorganisms in the natural environment, and will not cause pollution to the environment. At the same time, polyvinyl alcohol is non-toxic, tasteless, and harmless to the human body, and will not cause harm to human health and the environment.

[0021] The invention adds xanthan gum to polyvinyl alcohol, which has the following effects: 1. Improve mechanical properties: enhance tensile strength. The addition of xanthan gum enhances the tensile strength of the polyvinyl alcohol film through intermolecular interaction, making it more durable. 2. Enhance thermal insulation and water resistance: The hydrophobic groups in the xanthan gum hinder the flow of water molecules. At the same time, the pure polyvinyl alcohol film has good gas barrier properties. After the two are blended and compounded, the barrier properties of the composite film are increased. The liquid ground film has better thermal insulation and water resistance.

[0022] The invention uses straw powder and wood ash as raw materials. The straw powder and wood ash are purely natural, and the products generated during degradation will not pollute the environment, while increasing soil fertility.

[0023] The invention sprays an organic solvent containing polyvinyl alcohol, straw powder, plant ash and xanthan gum onto the soil surface, and forms a biodegradable mulch film with high mechanical properties, good water resistance and obvious temperature increase and entropy retention after a cross-linking reaction and natural air drying. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 : Actual picture of the liquid ground film dispersion obtained in Example 1.

[0025] Figure 2 : Actual picture of the mulch film obtained after spraying and air-drying the liquid mulch film dispersion obtained in Example 1.

[0026] Figure 3 : Comparison chart of the thermal insulation and entropy retention effects of the liquid mulch obtained in Example 1.

[0027] Figure 4 : Comparison chart of the thermal insulation and entropy retention effects of the liquid mulch obtained in Example 2. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution in the present invention will be described clearly and completely below, and the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] A specific embodiment provides a liquid ground film, and its composition by weight is as follows:

[0030] 20-25 parts of polyvinyl alcohol; 10-13 parts of crushed straw; 15-20 parts of wood ash; 20-24 parts of xanthan gum; 100-120 parts of water.

[0031] Specifically, the molecular weight of the polyvinyl alcohol is 170,000-180,000. The straw is corn straw, and the particle size after crushing is 80-200 mm. The plant ash is the residue after burning straw or rice straw, and the particle size is 0.5-2 mm. The viscosity of the xanthan gum is ≥1200 mPa·s, and the ignition residue is 5.5-16.0. Unless otherwise specified, the remaining raw materials are obtained through conventional commercial channels.

[0032] The specific embodiment also provides a method for preparing the above-mentioned liquid mulch film, comprising the following steps:

[0033] The polyvinyl alcohol is mixed with water to prepare a polyvinyl alcohol solution; the straw crushed material, wood ash and xanthan gum are added in sequence and mixed and stirred to evenly disperse the materials and then let them stand to obtain a liquid mulch film.

[0034] The specific implementation also provides the application of the above-mentioned liquid mulch in agriculture, including spraying the above-mentioned liquid mulch on the soil surface and forming a mulch after natural air drying. Specifically, the spraying amount of the liquid mulch on the soil surface is 80 to 100 L / mu. Specific application scenarios include but are not limited to soil insulation or soil waterproofing.

[0035] The specific embodiment also provides a soil heat preservation method, which includes spraying the above-mentioned liquid ground film on the soil surface and allowing it to dry naturally to form a ground film covering the soil surface.

[0036] Example 1

[0037] The specific amount of each ingredient is: 20g polyvinyl alcohol; 10g straw crushed material; 15g wood ash; 20g xanthan gum; 100g water.

[0038] Step 1: Pour polyvinyl alcohol powder into a beaker at room temperature, add a certain amount of distilled water, stir magnetically, heat in a water bath, and prepare a polyvinyl alcohol solution.

[0039] Step 2: Use a grinder to grind a certain amount of straw into powder, add the straw powder into the polyvinyl alcohol solution, and stir until uniform to obtain dispersion A.

[0040] Step 3: Add plant ash and xanthan gum to dispersion A in sequence, and stir again until uniform to obtain dispersion B. Let the prepared dispersion B stand for 24 hours to obtain liquid mulch dispersion C. See attached for the actual picture Figure 1 shown.

[0041] Step 4: Spray the dispersion C on the soil surface and allow it to dry naturally to form a degradable mulch film. Figure 2 shown.

[0042] Example 2

[0043] The specific amount of each ingredient is: 25g polyvinyl alcohol; 13g straw crushed material; 20g wood ash; 24g xanthan gum; 120g water.

[0044] Step 1: Pour polyvinyl alcohol powder into a beaker at room temperature, add a certain amount of distilled water, stir magnetically, heat in a water bath, and prepare a polyvinyl alcohol solution.

[0045] Step 2: Use a grinder to grind a certain amount of straw into powder, add the straw powder into the polyvinyl alcohol solution, and stir until uniform to obtain dispersion A.

[0046] Step 3: Add plant ash and xanthan gum to dispersion A in sequence, and stir again until uniform to obtain dispersion B. Allow the prepared dispersion B to stand for 24 hours to obtain liquid mulch dispersion C.

[0047] Step 4: Spray the dispersion C on the soil surface and allow it to dry naturally to form a degradable mulch film.

[0048] Example 3

[0049] The specific amount of each ingredient is: polyvinyl alcohol 23g; straw crushed material 11g; wood ash 18g; xanthan gum 22g; water 11g.

[0050] Step 1: Pour polyvinyl alcohol powder into a beaker at room temperature, add a certain amount of distilled water, stir magnetically, heat in a water bath, and prepare a polyvinyl alcohol solution.

[0051] Step 2: Use a grinder to grind a certain amount of straw into powder, add the straw powder into the polyvinyl alcohol solution, and stir until uniform to obtain dispersion A.

[0052] Step 3: Add plant ash and xanthan gum to dispersion A in sequence, and stir again until uniform to obtain dispersion B. Allow the prepared dispersion B to stand for 24 hours to obtain liquid mulch dispersion C.

[0053] Step 4: Spray the dispersion C on the soil surface and allow it to dry naturally to form a degradable mulch film.

[0054] The liquid mulch obtained in Example 1 and Example 2 was tested for its effect on soil heat preservation and entropy retention. At the same time, 3wt%, 4wt%, 5wt%, 7wt%, and 8wt% polyvinyl alcohol solutions and plastic mulch were set as comparative examples. The mulch was a thickened PE film produced by Shandong Yuncheng Yiming Plastic Industry, and the film blowing and rolling width could reach 5 meters, and the unfolding width could reach 20 meters.

[0055] The test results are attached. Figure 3 and attached Figure 4 As shown. Among them, CH1 and CH2 are recorded open ground temperatures, CH3 and CH4 are measured as the land temperature sprayed with 3% polyvinyl alcohol solution, CH5 and CH6 are measured as the land temperature sprayed with 4% polyvinyl alcohol solution, CH7 and CH8 are measured as the land temperature sprayed with the liquid mulch obtained in Example 1 and Example 2, respectively, CH9 and CH10 are measured as the land temperature sprayed with 6% polyvinyl alcohol solution, CH11 and CH12 are measured as the land temperature sprayed with 7% polyvinyl alcohol solution, CH13 and CH14 are measured as the land temperature sprayed with 8% polyvinyl alcohol solution, and CH15 and CH16 are measured as the land temperature covered with plastic mulch.

[0056] Through the attachment Figure 3The analysis shows that the liquid mulch has a significant effect of heat preservation and entropy retention. Compared with blank land, the land temperature sprayed with the liquid mulch is significantly increased by 4 to 5 degrees. Compared with plastic mulch, the land temperature is significantly increased by 2 to 3 degrees.

[0057] Through the attachment Figure 4 The analysis shows that the liquid mulch has a significant effect of heat preservation and entropy retention. Compared with blank land, the temperature of the land sprayed with the liquid mulch is significantly increased. Compared with the plastic mulch, the land temperature is significantly increased.

Claims

1. A liquid ground film, characterized in that The composition is calculated by weight as follows: 20-25 parts of polyvinyl alcohol; 10-13 parts of crushed straw; 15-20 parts of wood ash; 20-24 parts of xanthan gum; 100-120 parts of water.

2. The liquid ground film according to claim 1, characterized in that The molecular weight of the polyvinyl alcohol is 170,000-180,000.

3. The liquid ground film according to claim 1, characterized in that The straw is corn straw, and the particle size after crushing is 80-200mm.

4. The liquid ground film according to claim 1, characterized in that The wood ash is the residue after burning straw or rice straw, and the particle size is 0.5-2 mm.

5. The liquid ground film according to claim 1, characterized in that The xanthan gum has a viscosity of ≥1200 mPa·s and a residue on ignition of 5.5-16.

0.

6. The method for preparing the liquid ground film according to claim 1, characterized in that The following steps are involved: The polyvinyl alcohol is mixed with water to prepare a polyvinyl alcohol solution; the straw crushed material, wood ash and xanthan gum are added in sequence and mixed and stirred to evenly disperse the materials and then let them stand to obtain a liquid mulch film.

7. The use of the liquid mulch film according to claim 1 in agriculture, characterized in that The method comprises spraying the liquid ground film on the soil surface and forming the ground film after natural air drying.

8. The use of the liquid mulch film in agriculture as claimed in claim 7, characterized in that The spraying amount of the liquid mulch film on the soil surface is 80-100 L / mu.

9. A ground film, characterized in that The liquid ground film according to claim 1 is sprayed on the soil surface and naturally dried to form the ground film.

10. A soil heat preservation method, characterized in that The method comprises spraying the liquid ground film according to claim 1 on the soil surface, and naturally drying the ground film to cover the soil surface.

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