An ultra-thin high water-resistant naturally degradable creped paper mulch and a preparation method thereof

Abstract

This invention discloses an ultra-thin, highly water-resistant, biodegradable crepe paper mulch film and its preparation method, aiming to replace traditional plastic mulch film, solve the problem of agricultural mulch film pollution, and promote the development of organic agriculture. This paper mulch film consists of layers of topcoat and core pulp. The topcoat is mainly composed of corn starch, silicone water-resistant agent, and water (by weight, 5-10 parts, 2-6 parts, and 84-93 parts, respectively). The silicone water-resistant agent contains carboxyl groups, alcohol hydroxyl groups, and polysiloxane oxygen-containing functional groups, possessing both excellent water resistance and environmental friendliness. The basis weight of the topcoat is 2-3 g / m². The core pulp is made from 100% unbleached recycled fiber, with a basis weight of 30-38 g / m². The paper mulch film has a wrinkling rate of 10-20%. The paper mulch film has excellent technical indicators: thickness 1.5-2.5 mm / 16 ply, longitudinal elongation 6-15%, longitudinal tensile strength 12000-20000 mN, longitudinal wet strength 4000-8000 mN, water absorption 20-35 g / m² (3 layers for 60 seconds), and visible light transmittance 0.3-1.5%. Its low cost, combined with high water resistance, good elasticity and biodegradability, makes it an ideal upgrade solution for the agricultural mulch film industry.

Description

Technical Field

[0001] This invention belongs to the field of green, low-carbon, and environmentally friendly agriculture and new material production technology, specifically relating to an ultra-thin, highly water-resistant, biodegradable crepe paper mulch film and its preparation method. Background Technology

[0002] Agricultural plastic film (referred to as agricultural film) has been widely used in agricultural production over the past four decades, playing a vital role in heat preservation, water retention, and promoting crop growth. However, the long-term excessive use of agricultural film and the lack of effective recycling and disposal measures have led to an increasingly serious problem of "white pollution," severely damaging the soil ecological environment. China implemented a plastic restriction order in 2008, and against this backdrop, biodegradable mulch film has become a research hotspot in the agricultural field.

[0003] After more than a decade of research and development, biodegradable mulch film (dual-degradable mulch film) has emerged, which is prepared by combining photodegradation and biodegradation. However, this type of mulch film produces small plastic particles after degradation. Although it does not have a significant negative impact on crop growth in the short term, as the usage time increases, plastic particles accumulate in the soil, which are not only difficult to remove, but also continue to pollute the soil and damage its structure.

[0004] Currently, domestic paper mulch film is still mainly in the research stage and has not yet achieved industrialized production. Limited by both production and raw material costs, existing paper mulch film is expensive, making it unaffordable for farmers. Most farmers still prefer to choose plastic mulch film, which offers better functionality and is cheaper. At the same time, existing biodegradable paper mulch film also suffers from poor functionality, lacking sufficient tensile strength and water resistance, making it unsuitable for automated film-laying machinery and unable to meet the complex needs of field planting. Traditional polyethylene mulch film is difficult to recycle 100%, and its residues cannot be degraded by soil microorganisms or absorbed by crops, further exacerbating soil pollution.

[0005] Therefore, developing a low-cost paper mulch film with high water resistance, good elasticity and biodegradability to replace traditional plastic mulch film has become the key to solving the current agricultural mulch film pollution problem and promoting the development of organic agriculture. Summary of the Invention

[0006] I. Purpose of the Invention To address the shortcomings of existing agricultural plastic mulch films, such as severe pollution, low dry and wet strength, lack of elasticity, and poor water resistance, as well as the high cost and insufficient functionality of existing paper mulch films, this invention provides an ultra-thin, highly water-resistant, biodegradable wrinkled paper mulch film and its preparation method. This paper mulch film is made from 100% recycled fibers, achieving low-cost production while possessing excellent elasticity, dry and wet strength, and water resistance. It is compatible with various mulching agricultural machinery, and its degradation increases soil organic matter, meeting the needs of ecological agriculture development.

[0007] II. Technical Solution To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows: An ultra-thin, highly water-resistant, biodegradable crepe paper mulch film is provided. The mulch film includes a top coating layer and a core pulp layer stacked together. The top coating layer is mainly composed of corn starch, organosilicon water-resistant agent and water. The components are expressed by weight as follows: 5-10 parts corn starch, 2-6 parts organosilicon water-resistant agent and 84-93 parts water.

[0008] The silicone water-resistant agent in the topcoat layer contains carboxyl groups, alcohol hydroxyl groups, and polysiloxane oxygen-containing functional groups, exhibiting excellent water resistance and being environmentally friendly. The basis weight of the topcoat layer is 2g / m²-3g / m², the basis weight of the core pulp is 30g / m²-38g / m², the wrinkling rate of the paper film is 10-20%, and the core pulp is made from 100% unbleached recycled fibers.

[0009] The technical specifications of this paper mulch film meet the following requirements: thickness of 1.5-2.5mm / 16ply, longitudinal elongation of 6-15%, longitudinal tensile strength of 12000-20000mN, longitudinal wet strength of 4000-8000mN, water absorption of 20-35g / m² (3 layers for 60 seconds), and visible light transmittance of 0.3-1.5%.

[0010] An ultra-thin, highly water-resistant, biodegradable crepe paper mulch film and its preparation method. The method for preparing the aforementioned mulch film specifically includes the following steps: Preparation of core pulp (S1) S11 pulping: Waste paper is added to a pulper for pulping to produce high-consistency pulp; S12 Impurity Removal: The slurry undergoes a series of processes including high-consistency sand removal, coarse screening, low-consistency sand removal, fine screening, multi-disc thickening, and thermal dispersion. Specifically, high-consistency sand removal uses a high-consistency sand remover to remove heavy impurities, primarily metals; coarse screening uses a coarse pressure screen to separate larger impurities; low-consistency sand removal uses a low-consistency heavy slag remover to remove heavy impurities, primarily sand particles; fine screening uses a fine pressure screen to remove fine impurities; multi-disc thickening uses a multi-disc thickener to concentrate the slurry; and thermal dispersion further refines the molten materials in the slurry, ultimately yielding a pure, concentrated slurry. S13 Pulping and Storage: The pulp after removing impurities is sent to a high-consistency refiner for fiber-reducing pulping. After pulping, the pulp is stored in a pulping tower for later use. S14 Slurry Tank Sizing: AKD and aluminum sulfate are added to the slurry tank to sizing the slurry and improve its basic properties; S15 Flow System: Dilutes the sizing pulp to a concentration of 0.5%-1.0%, and adds wet strength agent and dry strength agent to enhance the dry and wet strength of the paper film; S16 Molding: The diluted slurry is shaped using a molding screen, while simultaneously dewatering, increasing the slurry concentration from 0.5%-1.0% to 20%-25%. S17 pressing: The slurry after molding is pressed to further increase its concentration to 46%-55%; S18 Drying: The pressed pulp is dried to increase the pulp concentration to 90%-95%, forming qualified core pulp.

[0011] Coating and sizing (S2): The core pulp obtained in step S1 is coated and sizing is performed to form a top coating layer and a bottom sizing layer on the two surfaces of the core pulp, respectively, to obtain the base paper film.

[0012] Calendering and winding (S3): Calendering the base paper mulch film improves its surface smoothness and density. Then, winding it up produces an ultra-thin, highly water-resistant, biodegradable creped paper mulch film.

[0013] III. Beneficial Effects Compared with the prior art, the present invention has the following beneficial effects: Excellent performance and suitable for agricultural needs: This paper mulch film has good water resistance, elasticity and high dry and wet strength. The longitudinal elongation can reach 6-15%, and the longitudinal wet strength is not less than 4000mN. It can be used in various automated agricultural film laying machines and can be used stably in both dry and irrigated fields. The film laying operation is convenient and it is not easy to become brittle. It can effectively play the roles of heat preservation, water retention, shading and weed suppression.

[0014] Supporting organic farming and improving quality of life and ecology: Paper mulch film is made of natural fibers and has the characteristics of being light-proof and opaque. Combined with its function of shading and suppressing weeds, it eliminates the need for herbicides, providing favorable conditions for the cultivation of organic crops. At the same time, it avoids the pollution of soil and environment by herbicides, which helps to improve the quality of agricultural products and people's living standards.

[0015] Green and low-carbon, achieving ecological recycling: This invention replaces plastic with paper, using 100% natural recycled fibers as raw materials, making full use of waste resources, and the production process adopts a low-energy-consumption technology, resulting in a low carbon footprint. After crop harvest, the paper mulch film can be naturally degraded by microorganisms in the soil without additional collection and treatment. The degradation products can increase soil organic matter, while also loosening the soil, preventing soil compaction, and improving soil structure, which meets the requirements of ecological agriculture development.

[0016] Low cost and easy to promote: By adopting recycled fiber raw materials and optimizing production processes, the production cost and raw material cost of paper mulch film have been significantly reduced, solving the problem of high price and difficulty in promotion of existing paper mulch film. This lays the foundation for large-scale replacement of traditional plastic mulch film and has broad market application prospects. Attached Figure Description

[0017] Appendix Figure 1 Simplified process flow diagram for the production of ultra-thin water-resistant wrinkled paper mulch film Detailed Implementation

[0018] The present invention will be further described in detail below with reference to specific embodiments. These embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention.

[0019] Example 1 This embodiment provides an ultra-thin, highly water-resistant, biodegradable crepe paper mulch film, comprising a top coating layer and a core pulp. The components of the top coating layer by weight are: 5 parts corn starch, 2 parts organosilicon water-resistant agent, and 93 parts water. The basis weight of the top coating layer is 2 g / m², the basis weight of the core pulp is 30 g / m², and the crepe rate of the mulch film is 10%.

[0020] The preparation method of this paper mulch film is as follows: Pulping: Recycled corrugated cardboard waste paper is added to a hydrauler to produce high-consistency pulp; Impurity removal: The high-concentration slurry is fed into a high-concentration sand remover to remove heavy impurities such as metals. Then, it is separated into large-sized impurities by a coarse pressure screen. Subsequently, it is passed through a low-concentration heavy slag remover to remove sand particles and other impurities. Fine pressure screens remove small impurities. After being concentrated by a multi-disc thickener, it is subjected to thermal dispersion treatment to refine the hot melt. Pulping and storage: The pure pulp is sent to a high-consistency refiner for fiberization and pulping, and then stored in a pulping tower after pulping; Sizing in the slurry forming tank: Add AKD and aluminum sulfate to the slurry forming tank to sizing the slurry; Delivery system: Dilute the slurry to a concentration of 0.5%, and add wet strength agent and dry strength agent; Forming: The slurry is formed using a forming screen and then dehydrated, increasing the slurry concentration to 20%. Pressing: Press the pulp to a concentration of 46%; Drying: Dry the pulp to a concentration of 90% to obtain core pulp; Coating and sizing: A top coating layer and a bottom sizing layer are formed on both sides of the core pulp to produce the base paper film; Calendering and winding: The base paper film is calendered and then wound to obtain the finished product.

[0021] The paper mulch film was tested and found to have a thickness of 1.5mm / 16ply, a longitudinal elongation of 6%, a longitudinal tensile strength of 12000mN, a longitudinal wet strength of 4000mN, a water absorption of 20g / m² (3 layers for 60 seconds), and a visible light transmittance of 0.3%, meeting the technical requirements.

[0022] Example 2 This embodiment provides an ultra-thin, highly water-resistant, biodegradable crepe paper mulch film. The components of the topcoat layer by weight are: 8 parts corn starch, 4 parts organosilicon water-resistant agent, and 88 parts water. The basis weight of the topcoat layer is 2.5 g / m², the basis weight of the core pulp is 34 g / m², and the crepe rate of the paper mulch film is 15%.

[0023] In its preparation method, the concentration of the slurry after dilution in step S15 is 0.8%, the concentration of the slurry after molding in step S16 is 22%, the concentration after pressing in step S17 is 50%, and the concentration after drying in step S18 is 92%. The remaining steps are the same as in Example 1.

[0024] Tests show that the paper mulch film has a thickness of 2.0mm / 16ply, a longitudinal elongation of 10%, a longitudinal tensile strength of 16000mN, a longitudinal wet strength of 6000mN, a water absorption of 28g / m² (3 layers in 60 seconds), and a visible light transmittance of 1.0%. Its performance is well-balanced and suitable for various agricultural planting scenarios.

[0025] Example 3 This embodiment provides an ultra-thin, highly water-resistant, biodegradable crepe paper mulch film. The components of the topcoat layer are as follows by weight: 10 parts corn starch, 6 parts organosilicon water-resistant agent, and 84 parts water. The basis weight of the topcoat layer is 3 g / m², the basis weight of the core pulp is 38 g / m², and the crepe rate of the mulch film is 20%.

[0026] In its preparation method, the concentration of the slurry after dilution in step S15 is 1.0%, the concentration of the slurry after molding in step S16 is 25%, the concentration after pressing in step S17 is 55%, the concentration after drying in step S18 is 95%, and the remaining steps are the same as in Example 1.

[0027] Tests showed that the paper mulch film has a thickness of 2.5mm / 16ply, a longitudinal elongation of 15%, a longitudinal tensile strength of 20000mN, a longitudinal wet strength of 8000mN, a water absorption of 35g / m² (3 layers for 60 seconds), and a visible light transmittance of 1.5%. It exhibits excellent strength and water resistance, making it suitable for use in field planting in complex environments.

[0028] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made based on the description and drawings of the present invention, or direct / indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A type of ultra-thin, highly water-resistant, biodegradable crepe paper mulch, characterized in that, The film comprises a layered top coating and a core pulp. The top coating is mainly composed of corn starch, silicone water-resistant agent, and water, with the following weight fractions: 5-10 parts corn starch, 2-6 parts silicone water-resistant agent, and 84-93 parts water. The core pulp is made of 100% unbleached recycled fiber. The basis weight of the top coating is 2g / m²-3g / m², the basis weight of the core pulp is 30g / m²-38g / m², and the wrinkling rate of the paper film is 10-20%.

2. The ultra-thin, highly water-resistant, biodegradable crepe paper mulch film as described in claim 1, characterized in that, The organosilicon water-resistant agent in the topcoat layer contains carboxyl groups, alcohol hydroxyl groups, and polysiloxane oxygen-containing functional groups.

3. The ultra-thin, highly water-resistant, biodegradable crepe paper mulch film as described in claim 2, characterized in that, The technical specifications of the paper mulch film are as follows: thickness of 1.5-2.5mm / 16ply, longitudinal elongation of 6-15%, longitudinal tensile strength of 12000-20000mN, longitudinal wet strength of 4000-8000mN, water absorption of 20-35g / m² (3 layers for 60 seconds), and visible light transmittance of 0.3-1.5%.

4. A method for preparing an ultra-thin, highly water-resistant, biodegradable crepe paper mulch film as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Core pulp is prepared from waste paper through a papermaking process; S2. Coating and surface sizing are applied to the core pulp obtained in S1, forming a top coating layer and a bottom sizing layer on the two surfaces of the core pulp to form the base paper film. S3. Calender and roll the original paper mulch film formed in S2 to obtain the finished paper mulch film.

5. The method for preparing the ultra-thin, highly water-resistant, biodegradable crepe paper mulch film according to claim 4, characterized in that, Step S1 specifically includes the following steps: S11. Pulping: Waste paper is added to a pulper for pulping to obtain high-consistency pulp. S12. Impurity Removal: The slurry undergoes high-consistency sand removal, coarse screening, low-consistency sand removal, fine screening, multi-disc concentration and thermal dispersion treatments in sequence to remove various impurities from the slurry and refine the hot melt. S13. Pulping and storage: The pulp after removing impurities is sent to a high-consistency refiner for fiberization and pulping, and then stored in a pulping tower. S14. Sizing in the slurry tank: Add AKD and aluminum sulfate to the slurry tank to sizing the slurry; S15, Flow system: Dilutes the slurry after sizing to obtain a slurry with a concentration of 0.5%-1.0%, and adds wet strength agent and dry strength agent; S16. Shaping: The slurry is shaped and dewatered using a shaping screen, increasing the slurry concentration to 20%-25%; S17. Pressing: The pulp after pressing is made to increase its concentration to 46%-55%; S18. Drying: The pressed pulp is dried to increase the pulp concentration to 90%-95% to form core pulp.

6. The method for preparing the ultra-thin, highly water-resistant, biodegradable crepe paper mulch film according to claim 5, characterized in that, In step S12, the high-concentration sand removal uses a high-concentration sand remover to remove heavy impurities, mainly metals; the coarse screening uses a coarse pressure screen to separate larger impurities; the low-concentration sand removal uses a low-concentration heavy slag remover to remove heavy impurities, mainly sand particles; and the fine screening uses a fine pressure screen to remove fine impurities.

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