Plant fiber mould pressing flowerpot and manufacturing method thereof

Abstract

The invention relates to the technical field of degradable flowerpots, in particular to a plant fiber mould pressing flowerpot and a manufacturing method of the plant fiber mould pressing flowerpot. 10 to 20 parts of a composite binder; wherein the plant fiber comprises at least one of straw and wheat straw, and the length of the straw and the wheat straw is 5-10 mm; the composite binder comprises the following components in parts by weight: 60-80 parts of modified urea-formaldehyde resin; 15 to 25 parts of epoxy resin; according to the plant fiber flowerpot, the plant fiber flowerpot with the height of 15 cm or above is successfully manufactured, and the industry blank is filled up; balanced strength distribution from bottom to top is achieved through fiber orientation and gradient density forming. The composite binder system obviously reduces the water absorption rate of the flowerpot and prolongs the service life of the product; the degradation speed is accurately controlled by regulating and controlling the ratio of the plant fibers to the binder.

Description

Technical Field

[0001] The present invention relates to the technical field of degradable flower pots, and in particular to a plant fiber molded flower pot and a manufacturing method thereof. Background Art

[0002] In the fields of horticulture and agriculture, flower pots have always played an important role as a carrier for plant growth. However, the traditional method of making flower pots faces many challenges. First, although common plastic flower pots are low-cost and easy to mass-produce, their non-biodegradable nature has caused a serious burden on the environment. Secondly, although flower pots made of ceramic or clay are environmentally friendly, they are often expensive and fragile, making them unsuitable for large-scale applications.

[0003] In recent years, with the improvement of environmental awareness, the technology of making flower pots with plant fibers as raw materials has gradually emerged. This type of technology usually uses agricultural waste such as crop straw and rice husks as the main raw materials, and makes flower pots through processes such as crushing and molding. However, there are still many limitations in the existing technology. First, the hydrophobicity of plant fibers is poor, resulting in high water absorption and easy deformation of the flower pots. Secondly, the bonding strength between fibers is insufficient, which makes the flower pots low in strength, especially when making flower pots with a height of more than 10 cm, cracking or deformation often occurs. Furthermore, it is difficult to achieve effective stretching of plant fibers in the vertical direction with the existing technology, which seriously limits the height of the flower pots.

[0004] The closest existing technology usually uses the method of crushing plant fibers into powder, then mixing them with a small amount of binder, and then making flower pots by molding. Although this method makes use of agricultural waste to a certain extent, there are still several key problems: first, the molding height is limited, and it is difficult to make flower pots with a height of more than 15cm; second, the wall thickness is uneven, resulting in uneven strength distribution; third, the degradation rate is difficult to control, either too fast to affect the service life, or too slow to achieve a true environmental protection effect.

[0005] In view of the above problems, there is an urgent need for a new type of plant fiber molded flower pot and a manufacturing method thereof, which can make full use of agricultural waste to achieve the manufacture of flower pots with a height of at least 15 cm, while ensuring the strength, water resistance and controllable degradability of the product. In addition, the method should also have good industrialization potential and be able to achieve large-scale, low-cost production. Summary of the invention

[0006] In view of the above problems, the present invention provides a plant fiber molded flowerpot and a manufacturing method thereof.

[0007] The object of the present invention is to provide a plant fiber molded flower pot, which is made of the following components in parts by weight:

[0008] 80-90 parts of plant fiber;

[0009] Composite adhesive 10-20 parts;

[0010] Wherein, the plant fiber comprises at least one of rice straw and wheat straw with a length of 5-10 mm;

[0011] The composite binder comprises the following components in parts by weight:

[0012] 60-80 parts of modified urea-formaldehyde resin;

[0013] Epoxy resin 15-25 parts;

[0014] Polyvinyl alcohol 5-15 parts.

[0015] Preferably, the flowerpot further comprises the following additives:

[0016] Based on the total weight of plant fiber and composite binder,

[0017] 0.5-1% calcium stearate;

[0018] 0.3-0.5% silane coupling agent;

[0019] 0.1-0.2% dicumyl peroxide.

[0020] Preferably, the molecular weight of the modified urea-formaldehyde resin is 3000-5000, the molecular weight of the epoxy resin is 700-1000, the hydrolysis degree of the polyvinyl alcohol is 87-89%, and the molecular weight is 44000-48000.

[0021] Preferably, the height of the flowerpot is not less than 15 cm.

[0022] The method for manufacturing the plant fiber molded flowerpot comprises the following steps:

[0023] (1) Plant fiber pretreatment:

[0024] First, cut the plant fiber into 2-10 mm length;

[0025] Secondly, soak in 1-3% NaOH solution at 60-70°C for 2-4 hours;

[0026] Then, rinse with clean water until neutral;

[0027] Finally, dry to a moisture content of 5-8%;

[0028] (2) Formula mixing:

[0029] uniformly mixing the pretreated plant fibers with the composite binder and the additives;

[0030] (3) Compression molding:

[0031] After the mixture is obtained, it is loaded into a mold for compression molding.

[0032] Preferably, the compression molding step comprises:

[0033] (1) Preheating stage:

[0034] Preheat the mixture to 60-70°C for 3-5 minutes and pre-compact at 0.5MPa;

[0035] (2) Main pressure stage:

[0036] First, maintain the pressure at 1.5 MPa for 30 seconds;

[0037] Secondly, increase the pressure to 2.5MPa and maintain for 60 seconds;

[0038] Again, increase the pressure to 3 MPa and maintain for 120 seconds;

[0039] (3) Demolding stage:

[0040] Cool down to 100°C at a rate of 2°C / min;

[0041] Then, maintain a pressure of 0.5 MPa for 5 minutes for post-curing;

[0042] Finally, 0.6-0.8MPa compressed air was used to assist demoulding.

[0043] Preferably, the temperature control of the main pressure stage is:

[0044] First, the starting temperature is 130°C;

[0045] Secondly, the temperature was raised to 160°C at a rate of 5°C / min;

[0046] Then, the temperature was maintained at 160°C until the molding was completed.

[0047] Preferably, the mold comprises:

[0048] Inner wall structure: adopts variable-section spiral groove design, with a top groove depth of 1.5mm and a bottom groove depth of 0.5mm; the spiral groove angle gradually decreases from 45° at the top to 30° at the bottom; the pitch gradually decreases from 15mm at the top to 8mm at the bottom;

[0049] Bottom structure: There is a protrusion in the center, the diameter of which is 1 / 3 of the diameter of the bottom of the mold, the height is 5-8mm, and the edge of the protrusion is designed to be an angle of 45°.

[0050] As a preference, it also includes a fiber orientation step:

[0051] Install electromagnetic coils on the bottom and side walls of the mold;

[0052] During the preheating stage, a low-frequency alternating current of 10-20 Hz is introduced;

[0053] The magnetic field strength generated by the alternating current is 0.1-0.2 Tesla.

[0054] Preferably, the method further comprises a gradient density forming step:

[0055] The density of the bottom of the mold is 7-8 pieces / cm 2 The compaction rod;

[0056] The density of the top of the mold is 5-6 pieces / cm 2 The compaction rod;

[0057] Wherein, the modified urea-formaldehyde resin in the composite adhesive further contains 5-8% of a flexible epoxy resin, and the molecular weight of the flexible epoxy resin is 500-700;

[0058] Furthermore, the composite adhesive further comprises 1-2% of an organic silicon modifier.

[0059] The technical solution and chemical mechanism of the present invention:

[0060] The present invention cleverly solves the above technical problems through a series of innovative designs. First, in terms of raw material selection, the present invention uses plant fibers with a length of 2-10 mm instead of traditional powdered fibers. This selection is based on the consideration of the mechanical properties of the fibers. Longer fibers can form a network structure and provide better mechanical strength.

[0061] Secondly, the present invention adopts a unique composite binder system, including modified urea-formaldehyde resin, epoxy resin and polyvinyl alcohol. From the perspective of chemical mechanism, these three components form a multi-scale cross-linked network. The methyl alcohol group (-CH2OH) in the modified urea-formaldehyde resin undergoes a condensation reaction with the hydroxyl group (-OH) on the surface of the plant fiber to form a stable covalent bond. The epoxy group of the epoxy resin opens under heating conditions and reacts with the fiber and other resin components, increasing the cross-linking density of the system. Polyvinyl alcohol forms hydrogen bonds with the fiber through its abundant hydroxyl groups, improving the interfacial bonding between the fiber and the resin.

[0062] Thirdly, the present invention introduces innovative fiber orientation technology. By applying an alternating magnetic field during the molding process and utilizing the paramagnetism of trace metal ions in plant fibers, partial orientation of the fibers in the vertical direction is achieved. This process can be explained by the spin theory in quantum mechanics. The external magnetic field causes the paramagnetic ions in the fibers to be oriented, thereby driving the orientation of the entire fiber.

[0063] In addition, the present invention also adopts gradient density molding and innovative mold design. Gradient density molding creates a density gradient from bottom to top by controlling the compaction degree at different heights, which helps the flow of materials during the molding process. The variable cross-section spiral groove design of the mold cleverly utilizes the principles of fluid mechanics to increase the driving force for the upward flow of materials.

[0064] Finally, the optimized molding process matches the rheological properties of the material. The segmented pressurization and temperature control scheme takes into account the viscoelastic changes of the material at different temperatures and pressures, ensuring uniform distribution and full cross-linking of the material in the mold.

[0065] Beneficial effects of the present invention:

[0066] 1. Height breakthrough: We have successfully realized the manufacturing of plant fiber flower pots with a height of more than 15cm, filling the gap in the industry.

[0067] 2. Balanced strength: Balanced strength distribution from bottom to top is achieved through fiber orientation and gradient density molding.

[0068] 3. Improved water resistance: The composite adhesive system significantly reduces the water absorption rate of the flower pot and increases the service life of the product.

[0069] 4. Controllable degradation: By adjusting the ratio of plant fiber to binder, precise control of degradation rate is achieved.

[0070] 5. Environmentally friendly: Make full use of agricultural waste, reduce the use of plastic, and comply with the concept of circular economy.

[0071] 6. Cost-effectiveness: Simplified production process and wide sources of raw materials make large-scale industrial production possible.

[0072] 7. Versatility: The unexpectedly discovered surface hydrophobicity and self-cleaning ability bring additional application value to the product.

[0073] In addition, the flowerpot of the present invention uses plant fiber as the main raw material, and the binder is selected from modified urea-formaldehyde resin, epoxy resin and polyvinyl alcohol. The flowerpot has good air permeability and water permeability, which is conducive to plant growth. During the growth period of flowers, the pot body will gradually decompose as a supplementary organic fertilizer for flowers until it is completely degraded and does not need to be recycled; compared with the pulp method, the raw material source of the present invention is wide, less water is used, the energy used for dehydration is saved, and the production cost is low; the present invention adopts a molding process for one-time molding, the production process is simple, and it is convenient for large-scale industrial production; by adjusting the ratio of plant fiber to binder and the production process parameters, the flowerpot of the present invention has good mechanical strength and air permeability and water permeability, and is suitable for the planting of various flowers.

[0074] In summary, the present invention not only solves the key problems in the prior art, but also achieves a comprehensive improvement in performance through a number of innovative designs, opens up a new direction for the application of plant fiber composite materials, and has important theoretical significance and practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 The present invention is a schematic diagram of the structure of the plant fiber molded flower pot.

[0076] Figure 2 Another structural schematic diagram of the invented plant fiber molded flowerpot.

[0077] Figure 3 Another structural top view of the invented plant fiber molded flowerpot.

[0078] Figure 4 Another bottom view of the plant fiber molded flower pot of the invention. DETAILED DESCRIPTION

[0079] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0080] Embodiment 1: A plant fiber molded flowerpot and a method for manufacturing the same

[0081] Please refer to Figure 1-4 The plant fiber molded flowerpot of this embodiment is made of the following components by weight: 85 parts of plant fiber and 15 parts of composite binder. The plant fiber is selected from straw with a length of 5 mm; the composite binder includes the following components by weight: 70 parts of modified urea-formaldehyde resin, 20 parts of epoxy resin, and 10 parts of polyvinyl alcohol. In addition, 0.5% of calcium stearate, 0.3% of silane coupling agent (KH-550), and 0.1% of diisopropylbenzene peroxide are added based on the total weight of the plant fiber and the composite binder.

[0082] In this embodiment, the molecular weight of the modified urea-formaldehyde resin is 3000, the molecular weight of the epoxy resin is 700, the hydrolysis degree of the polyvinyl alcohol is 87%, and the molecular weight is 44000. This combination can provide good bonding strength while ensuring certain toughness and water resistance.

[0083] The manufacturing method of the plant fiber molded flower pot comprises the following steps:

[0084] (1) Plant fiber pretreatment:

[0085] First, cut the straw to 2mm length;

[0086] Secondly, soak in 1% NaOH solution at 60°C for 2 hours;

[0087] Then, rinse with clean water until neutral;

[0088] Finally, it is dried to a moisture content of 5%.

[0089] (2) Formula mixing:

[0090] The pretreated plant fibers are uniformly mixed with the composite binder and additives.

[0091] (3) Compression molding:

[0092] After the mixture is obtained, it is loaded into a mold for compression molding. The compression molding steps include:

[0093] a) Preheating stage: preheat the mixture to 60°C for 3 minutes and pre-compact at 0.5MPa;

[0094] b) Main pressure stage:

[0095] First, maintain the pressure at 1.5 MPa for 30 seconds;

[0096] Secondly, increase the pressure to 2.5MPa and maintain for 60 seconds;

[0097] Again, the pressure was increased to 3 MPa and maintained for 120 seconds.

[0098] Temperature control: The starting temperature is 130°C, which is increased to 160°C at a rate of 5°C / min, and then maintained at 160°C until the molding is completed.

[0099] c) Demolding stage:

[0100] Cool down to 100°C at a rate of 2°C / min;

[0101] Then, maintain a pressure of 0.5 MPa for 5 minutes for post-curing;

[0102] Finally, 0.6 MPa compressed air is used to assist demoulding to obtain the plant fiber molded flower pot, the structure of which is as follows: Figure 1 shown.

[0103] In this embodiment, the mold adopts a special design. The inner wall structure is a variable-section spiral groove design, with a top groove depth of 1.5mm and a bottom groove depth of 0.5mm; the spiral groove angle gradually decreases from 45° at the top to 30° at the bottom; the pitch gradually decreases from 15mm at the top to 8mm at the bottom. A protrusion is provided at the center of the bottom structure, with a diameter of 1 / 3 of the diameter of the bottom of the mold and a height of 5mm. The edge of the protrusion is designed to be an angle of 45°. This design helps to improve the fluidity and molding performance of the material.

[0104] In addition, this embodiment also uses fiber orientation technology and gradient density molding method. Electromagnetic coils are installed at the bottom and side walls of the mold, and a low-frequency alternating current of 10 Hz is passed during the preheating stage to generate a magnetic field strength of 0.1 Tesla. The density of the mold bottom is 7 / cm 2 The top of the compaction rod has a density of 5 / cm 2 The application of these technologies significantly improves the strength and ductility of the flower pots.

[0105] Preferably, in the embodiment of the present invention, the modified urea-formaldehyde resin in the composite binder further comprises 5% of flexible epoxy resin (molecular weight of 500) and 1% of organosilicon modifier. This formula further improves the toughness and water resistance of the flower pot, and improves the interface bonding between the resin and the fiber.

[0106] Embodiment 2: A plant fiber molded flowerpot and its manufacturing method

[0107] The plant fiber molded flowerpot of this embodiment is made of the following components by weight: 90 parts of plant fiber and 10 parts of composite binder. The plant fiber is selected from wheat straw with a length of 10 mm; the composite binder includes the following components by weight: 80 parts of modified urea-formaldehyde resin, 15 parts of epoxy resin, and 5 parts of polyvinyl alcohol. In addition, 1% of calcium stearate, 0.5% of silane coupling agent (KH-550), and 0.2% of diisopropylbenzene peroxide are added based on the total weight of the plant fiber and the composite binder.

[0108] In this embodiment, the molecular weight of the modified urea-formaldehyde resin is 5000, the molecular weight of the epoxy resin is 1000, the hydrolysis degree of the polyvinyl alcohol is 89%, and the molecular weight is 48000. This combination can provide higher bonding strength and water resistance.

[0109] The manufacturing method of the plant fiber molded flower pot comprises the following steps:

[0110] (1) Plant fiber pretreatment:

[0111] First, cut the straw into 10mm length;

[0112] Secondly, soak in 3% NaOH solution at 70°C for 4 hours;

[0113] Then, rinse with clean water until neutral;

[0114] Finally, it is dried to a moisture content of 8%.

[0115] (2) Formula mixing:

[0116] The pretreated plant fibers are uniformly mixed with the composite binder and additives.

[0117] (3) Compression molding:

[0118] After the mixture is obtained, it is loaded into a mold for compression molding. The compression molding steps include:

[0119] a) Preheating stage: preheat the mixture to 70°C for 5 minutes and pre-compact at 0.5MPa;

[0120] b) Main pressure stage:

[0121] First, maintain the pressure at 1.5 MPa for 30 seconds;

[0122] Secondly, increase the pressure to 2.5MPa and maintain for 60 seconds;

[0123] Again, the pressure was increased to 3 MPa and maintained for 120 seconds.

[0124] Temperature control: The starting temperature is 130°C, which is increased to 160°C at a rate of 5°C / min, and then maintained at 160°C until the molding is completed.

[0125] c) Demolding stage:

[0126] Cool down to 100°C at a rate of 2°C / min;

[0127] Then, maintain a pressure of 0.5 MPa for 5 minutes for post-curing;

[0128] Finally, 0.8 MPa compressed air was used to assist demoulding.

[0129] In this embodiment, the mold design is the same as that of embodiment 1, but in terms of fiber orientation technology, a low-frequency alternating current of 20 Hz is introduced to generate a magnetic field strength of 0.2 Tesla. The density of the bottom of the mold is 8 / cm 2 The top of the compaction rod has a density of 6 / cm 2 This arrangement further improves the strength and molding properties of the flower pot.

[0130] Preferably, in the embodiment of the present invention, the modified urea-formaldehyde resin in the composite adhesive further comprises 8% of flexible epoxy resin (molecular weight of 700) and 2% of organosilicon modifier. This formula further improves the toughness and water resistance of the flower pot.

[0131] Embodiment 3: A plant fiber molded flowerpot and its manufacturing method

[0132] The plant fiber molded flowerpot of this embodiment is made of the following components in parts by weight: 87 parts of plant fiber and 13 parts of composite binder. Among them, the plant fiber is a mixture of rice straw and wheat straw with a length of 7.5 mm (1:1 ratio); the composite binder includes the following components in parts by weight: 75 parts of modified urea-formaldehyde resin, 17 parts of epoxy resin, and 8 parts of polyvinyl alcohol. In addition, 0.75% of calcium stearate, 0.4% of silane coupling agent (KH-550), and 0.15% of diisopropylbenzene peroxide are added based on the total weight of the plant fiber and the composite binder.

[0133] In this embodiment, the molecular weight of the modified urea-formaldehyde resin is 4000, the molecular weight of the epoxy resin is 850, and the degree of hydrolysis of polyvinyl alcohol is 88% and the molecular weight is 46000. This combination is intended to balance bonding strength, toughness and water resistance.

[0134] The manufacturing method of the plant fiber molded flower pot comprises the following steps:

[0135] (1) Plant fiber pretreatment:

[0136] First, cut the mixture of rice straw and wheat straw into 7.5 mm length;

[0137] Secondly, soak in 2% NaOH solution at 65°C for 3 hours;

[0138] Then, rinse with clean water until neutral;

[0139] Finally, it was dried to a moisture content of 6.5%.

[0140] (2) Formula mixing:

[0141] The pretreated plant fibers are uniformly mixed with the composite binder and additives.

[0142] (3) Compression molding:

[0143] After the mixture is obtained, it is loaded into a mold for compression molding. The compression molding steps include:

[0144] a) Preheating stage: preheat the mixture to 65°C for 4 minutes and pre-compact at 0.5 MPa;

[0145] b) Main pressure stage:

[0146] First, maintain the pressure at 1.5 MPa for 30 seconds;

[0147] Secondly, increase the pressure to 2.5MPa and maintain for 60 seconds;

[0148] Again, the pressure was increased to 3 MPa and maintained for 120 seconds.

[0149] Temperature control: The starting temperature is 130°C, which is increased to 160°C at a rate of 5°C / min, and then maintained at 160°C until the molding is completed.

[0150] c) Demolding stage:

[0151] Cool down to 100°C at a rate of 2°C / min;

[0152] Then, maintain a pressure of 0.5 MPa for 5 minutes for post-curing;

[0153] Finally, 0.7 MPa compressed air was used to assist demoulding.

[0154] In this embodiment, the mold design is the same as that in embodiment 1, but in terms of fiber orientation technology, a low-frequency alternating current of 15 Hz is introduced to generate a magnetic field strength of 0.15 Tesla. The density of the bottom of the mold is 7.5 / cm 2 The top of the compaction rod has a density of 5.5 / cm 2 This arrangement is designed to optimize the strength and forming properties of the flower pots.

[0155] Preferably, in the embodiment of the present invention, the modified urea-formaldehyde resin in the composite binder further comprises 6.5% of flexible epoxy resin (molecular weight is 600) and 1.5% of organosilicon modifier. This formula further balances the toughness, strength and water resistance of the flower pot.

[0156] Embodiment 4: A plant fiber molded flowerpot and a method for manufacturing the same

[0157] The plant fiber molded flowerpot of this embodiment is made of the following components by weight: 80 parts of plant fiber and 20 parts of composite binder. The plant fiber is selected from straw with a length of 8 mm; the composite binder includes the following components by weight: 60 parts of modified urea-formaldehyde resin, 25 parts of epoxy resin, and 15 parts of polyvinyl alcohol. In addition, 0.8% of calcium stearate, 0.45% of silane coupling agent (KH-550), and 0.18% of diisopropylbenzene peroxide are added based on the total weight of the plant fiber and the composite binder.

[0158] In this embodiment, the molecular weight of the modified urea-formaldehyde resin is 3500, the molecular weight of the epoxy resin is 800, the hydrolysis degree of the polyvinyl alcohol is 88.5%, and the molecular weight is 45000. This combination is intended to provide optimal bonding strength and processing performance.

[0159] The manufacturing method of the plant fiber molded flower pot comprises the following steps:

[0160] (1) Plant fiber pretreatment:

[0161] First, cut the straw to 8mm length;

[0162] Secondly, soak in 2.5% NaOH solution at 68°C for 3.5 hours;

[0163] Then, rinse with clean water until neutral;

[0164] Finally, it is dried to a moisture content of 7%.

[0165] (2) Formula mixing:

[0166] The pretreated plant fibers are uniformly mixed with the composite binder and additives.

[0167] (3) Compression molding:

[0168] After the mixture is obtained, it is loaded into a mold for compression molding. The compression molding steps include:

[0169] a) Preheating stage: preheat the mixture to 68°C for 4.5 minutes and pre-compact at 0.5 MPa;

[0170] b) Main pressure stage:

[0171] First, maintain the pressure at 1.5 MPa for 30 seconds;

[0172] Secondly, increase the pressure to 2.5MPa and maintain for 60 seconds;

[0173] Again, the pressure was increased to 3 MPa and maintained for 120 seconds.

[0174] Temperature control: The starting temperature is 130°C, which is increased to 160°C at a rate of 5°C / min, and then maintained at 160°C until the molding is completed.

[0175] c) Demolding stage:

[0176] Cool down to 100°C at a rate of 2°C / min;

[0177] Then, maintain a pressure of 0.5 MPa for 5 minutes for post-curing;

[0178] Finally, 0.75 MPa compressed air was used to assist demoulding.

[0179] In this embodiment, the mold design is the same as that in embodiment 1, but in terms of fiber orientation technology, a low-frequency alternating current of 18 Hz is introduced to generate a magnetic field strength of 0.18 Tesla. The density of the bottom of the mold is 7.8 / cm 2 The top of the compaction rod has a density of 5.8 / cm 2 This setting is designed to further optimize the strength and forming properties of the flower pot.

[0180] Preferably, in the embodiment of the present invention, the modified urea-formaldehyde resin in the composite binder further comprises 7% of flexible epoxy resin (molecular weight 650) and 1.8% of organosilicon modifier. This formula further optimizes the balance of toughness, strength and water resistance of the flower pot.

[0181] It is worth noting that the combination of a higher proportion of composite binder (20 parts) and a lower proportion of plant fiber (80 parts) in this embodiment is intended to provide better molding performance and surface finish. Among them, the higher content of epoxy resin (25 parts) helps to improve the water resistance and toughness of the product, while the increase in polyvinyl alcohol (15 parts) improves the compatibility between the fiber and the resin. This combination not only ensures the strength of the flower pot, but also significantly improves its durability and service life.

[0182] In addition, the fiber orientation technology and gradient density molding method used in this embodiment further enhance the overall performance of the flower pot. By applying a magnetic field of a specific frequency and intensity during the molding process, the plant fibers present a certain orientation, which not only improves the mechanical strength of the product, but also improves its crack resistance. At the same time, the gradient density molding technology ensures that the bottom of the flower pot has a higher strength, while the top maintains a certain ductility. This design cleverly solves the problem of uneven strength caused by the increase in height.

[0183] Comparative Example 1

[0184] This comparative example is intended to verify the effect of plant fiber length on product performance and is compared with Example 1.

[0185] A plant fiber molded flowerpot and a manufacturing method thereof, characterized in that the flowerpot is made of the following components in parts by weight: 85 parts of plant fiber and 15 parts of composite binder. The plant fiber is selected from straw with a length of 0.5 mm; and the composition of the composite binder is the same as that of Example 1.

[0186] The manufacturing method is substantially the same as that of Example 1, but in the plant fiber pretreatment step, the rice straw is cut to a length of 0.5 mm. Other steps and parameters remain unchanged.

[0187] The results show that the strength of the flowerpot made of plant fibers with a length of 0.5 mm is significantly lower than that of Example 1, and the surface roughness increases. This verifies the importance of the fiber length of 2-10 mm in the present invention, which ensures both sufficient mechanical strength and good surface quality.

[0188] Comparative Example 2

[0189] This comparative example is intended to verify the effect of the ratio of the composite binder components on the product performance, and is compared with Example 2.

[0190] A plant fiber molded flowerpot and a manufacturing method thereof, characterized in that the flowerpot is made of the following components in parts by weight: 90 parts of plant fiber and 10 parts of composite binder. The plant fiber is selected from wheat straw with a length of 10 mm; the composite binder includes the following components in parts by weight: 90 parts of modified urea-formaldehyde resin, 5 parts of epoxy resin, and 5 parts of polyvinyl alcohol.

[0191] The manufacturing method is basically the same as that of Example 2, except that the component ratio of the composite binder is changed.

[0192] The results show that the water resistance and toughness of the product are significantly reduced due to the significant reduction in the content of epoxy resin, which confirms the importance of the proportion of each component of the composite adhesive in the present invention, especially the key role of epoxy resin in providing water resistance and toughness.

[0193] Comparative Example 3

[0194] This comparative example is intended to verify the effect of fiber orientation technology on product performance and is compared with Example 3.

[0195] A plant fiber molded flowerpot and a method for manufacturing the same, wherein the components and basic manufacturing method of the flowerpot are the same as those of Example 3, but fiber orientation technology is not used.

[0196] In the manufacturing method, the compression molding step omits the process of introducing a low-frequency alternating current to generate a magnetic field.

[0197] The results show that the mechanical strength and crack resistance of the flower pot without fiber orientation treatment are inferior to those of Example 3. This verifies the importance of the fiber orientation technology in the present invention, which significantly improves the overall performance of the product.

[0198] Comparative Example 4

[0199] This comparative example is intended to verify the effect of the gradient density molding method on product performance and is compared with Example 4.

[0200] A plant fiber molded flowerpot and a method for manufacturing the same, wherein the components and basic manufacturing method of the flowerpot are the same as those of Example 4, but a gradient density molding method is not used.

[0201] In the manufacturing method, the bottom and top of the mold are both made of 7 pieces / cm 2 The compaction rod.

[0202] The results show that the flower pots without gradient density molding performed poorly in terms of the balance between bottom strength and top ductility, especially when the height exceeded 15 cm, which was more prone to cracks. This confirms the importance of the gradient density molding method in the present invention, which effectively solves the problem of uneven strength caused by increased height.

[0203] Comparative Example 5

[0204] This comparative example is intended to verify the effect of the plant fiber pretreatment process on product performance and is compared with Example 1.

[0205] A plant fiber molded flowerpot and a manufacturing method thereof, characterized in that the components of the flowerpot are the same as those in Example 1, but the plant fiber pretreatment process is different.

[0206] In the manufacturing method, the plant fiber pretreatment steps are as follows:

[0207] First, cut the straw into 5mm length;

[0208] Secondly, it is directly dried to a moisture content of 5%, omitting the alkalization step.

[0209] The other steps and parameters are the same as those in Example 1.

[0210] The results show that the flower pots made of plant fibers without alkalization treatment are significantly inferior to those in Example 1 in terms of strength, toughness and water resistance. This verifies the importance of the alkalization step in the present invention, which effectively removes part of the hemicellulose and lignin, increases the flexibility and reactivity of the fibers, and thus improves the performance of the final product.

[0211] Comparative Example 6

[0212] This comparative example is intended to verify the effect of mold design on product performance and is compared with Example 2.

[0213] A plant fiber molded flowerpot and a method for manufacturing the same, wherein the components and basic manufacturing method of the flowerpot are the same as those of Example 2, but the mold design is different.

[0214] In the manufacturing method, the mold adopts a common cylindrical design, the inner wall is smooth, and there is no spiral groove structure; the bottom is flat and there is no central protrusion.

[0215] The results show that the flower pots made using ordinary molds are inferior to Example 2 in terms of molding height and surface quality. In particular, when trying to make flower pots with a height of more than 15 cm, the success rate is significantly reduced, and the product wall thickness is uneven. This confirms the importance of the special mold design in the present invention, which effectively improves the fluidity and molding properties of the material, making it possible to make flower pots with a height of 15 cm and above.

[0216] Through these comparative examples, we can clearly see the innovation and superiority of the present invention in terms of plant fiber length selection, composite binder formulation, fiber orientation technology, gradient density molding method, plant fiber pretreatment process, and mold design. The synergistic effect of these innovative points enables the present invention to produce high-quality, high-performance plant fiber molded flower pots, which not only solves the problems existing in traditional flower pots, but also opens up a new way for the high-value utilization of agricultural waste.

[0217] The present invention has carried out the following test experiment design:

[0218] 1. Mechanical properties test

[0219] To evaluate the strength and toughness of the pots, we conducted compressive and flexural strength tests.

[0220] Test method: According to GB / T 1041-2008 standard, use a universal material testing machine to test. Cut the bottom of the flower pot into a square sample of 50mm×50mm×4mm to test its compressive strength. At the same time, cut the side wall of the flower pot into a long strip sample of 100mm×20mm×4mm to test its bending strength.

[0221] 2. Water absorption test

[0222] To evaluate the water resistance of the pots, we conducted a water absorption test.

[0223] Test method: According to GB / T 1934.1-2009 standard, immerse a 50mm×50mm×4mm sample in water at 23±2℃ for 24 hours and measure its mass increase percentage.

[0224] 3. Biodegradability test

[0225] To evaluate the environmental performance of the flower pots, we conducted a soil burial degradation test.

[0226] Test method: According to GB / T 19277.1-2011 standard, bury the sample of 50mm×50mm×4mm in active soil, cultivate it at 25±2℃ and relative humidity of 50±5%, and take it out every 30 days to measure the mass loss.

[0227] 4. Surface roughness test

[0228] To evaluate the surface quality of the flower pots, we conducted a surface roughness test.

[0229] Test method: Use a surface roughness meter to measure the arithmetic mean deviation Ra value of the sample surface according to GB / T 3505-2000 standard.

[0230] 5. Fiber orientation analysis

[0231] To evaluate the effect of fiber orientation technology, we conducted fiber orientation analysis.

[0232] Test method: Use X-ray diffraction (XRD) technology to measure the azimuthal distribution function (ODF) of the sample and calculate the Herman orientation factor.

[0233] 6. Heat deformation temperature test

[0234] To evaluate the heat resistance of the flower pots, we conducted a heat deformation temperature test.

[0235] Test method: According to GB / T 1634.2-2004 standard, use a heat deformation Vicat softening point tester to measure the heat deformation temperature of the sample under a load of 0.45MPa.

[0236] The test results are as follows:

[0237] Table 1: Mechanical and physical properties test results of each sample

[0238]

[0239]

[0240] Table 2: Biodegradability test results of each sample (mass loss percentage)

[0241] sample 30 days 60 days 90 days 120 days Example 1 5.2％ 12.8％ 22.5％ 35.7％ Example 2 4.8％ 11.9％ 21.3％ 33.8％ Example 3 5.0％ 12.3％ 21.9％ 34.5％ Example 4 4.5％ 11.2％ 20.1％ 32.3％ Comparative Example 1 6.8％ 15.7％ 26.9％ 41.2％ Comparative Example 2 5.5％ 13.6％ 23.8％ 37.1％ Comparative Example 3 5.3％ 13.1％ 23.0％ 36.2％ Comparative Example 4 4.7％ 11.6％ 20.8％ 33.1％ Comparative Example 5 6.1％ 14.5％ 25.2％ 39.3％ Comparative Example 6 5.4％ 13.3％ 23.4％ 36.8％

[0242] The results and discussion are as follows:

[0243] 1. Mechanical properties: The compressive strength and flexural strength of Examples 1-4 are significantly higher than those of the comparative examples. In particular, Example 4 has a compressive strength of 21.5 MPa and a flexural strength of 29.8 MPa, which is mainly due to the optimized fiber length, composite binder formula and fiber orientation technology. In contrast, the mechanical properties of Comparative Example 1 are significantly reduced due to the excessively short fibers.

[0244] 2. Water absorption: Examples 2 and 4 showed the lowest water absorption, 28.5% and 26.7%, respectively. This is attributed to the use of a higher proportion of epoxy resin and silicone modifier, which effectively improved the water resistance of the product. Comparative Examples 1 and 5 had higher water absorption, 38.5% and 36.9%, respectively, indicating that fiber length and pretreatment process have a significant effect on water resistance.

[0245] 3. Surface quality: Example 4 has the lowest surface roughness, with an Ra value of only 2.5 μm, which is due to the optimized fiber length and composite binder formula. Comparative Example 1 has the highest surface roughness, with an Ra value of 5.7 μm, which further confirms the importance of appropriate fiber length to surface quality.

[0246] 4. Fiber orientation: The Herman orientation factors of Examples 2 and 4 are 0.75 and 0.78 respectively, which are significantly higher than those of other samples, which verifies the effectiveness of the fiber orientation technology. Since Comparative Example 3 does not use the fiber orientation technology, its Herman orientation factor is only 0.45.

[0247] 5. Heat deformation temperature: Example 4 has the highest heat deformation temperature, reaching 101°C, which is mainly due to the optimized composite binder formula and high crosslinking density. Comparative Example 1 has the lowest heat deformation temperature, which is 85°C, indicating that the fiber length and binder formula have a significant effect on the heat resistance of the product.

[0248] 6. Biodegradability: All samples showed good biodegradability, but the degradation rate of Examples 1-4 was relatively moderate, with a mass loss of 32.3%-35.7% after 120 days. This moderate degradation rate not only ensures the stability of the product during its use period, but also allows for rapid degradation after disposal. Comparative Example 1 has the fastest degradation rate, with a mass loss of 41.2% after 120 days, which may lead to premature failure of the product during use.

[0249] In-depth analysis and unexpected technical effects:

[0250] 1. Synergistic enhancement effect: The present invention achieves synergistic improvement in mechanical strength, water resistance and surface quality by optimizing fiber length, composite binder formula and fiber orientation technology. In particular, Example 4 achieves the lowest water absorption and the best surface quality while maintaining high mechanical strength. This synergistic improvement in multiple properties is an unexpected technical effect and provides new ideas for the design of high-performance bio-based composite materials.

[0251] 2. Controllable biodegradability: The flowerpot of the present invention exhibits controllable biodegradability, which is achieved by precisely controlling the ratio of plant fiber to composite binder. In particular, Examples 2 and 4 maintain a moderate degradation rate while maintaining a low water absorption rate. This controllable degradation property allows the product to remain stable during its service life while being able to degrade quickly after being discarded, which is an unexpected balance effect.

[0252] 3. Improved thermal stability: The heat deformation temperature of Example 4 reached 101°C, which was beyond expectations. Generally, plant fiber-based composite materials have poor heat resistance, but the present invention significantly improves the heat resistance of the product by optimizing the composite binder formula and crosslinking density. This provides the possibility of expanding the application range of plant fiber composite materials.

[0253] 4. Multiple effects of fiber orientation: Fiber orientation technology not only improves the mechanical strength of the product, but also unexpectedly improves the dimensional stability and anti-warping performance of the product. This may be due to the oriented fiber network structure reducing the uneven distribution of internal stress, thereby improving the overall performance of the product.

[0254] 5. Surface functionalization: Although the initial design focused on surface roughness, the study found that the optimized surface structure also has certain hydrophobicity and self-cleaning capabilities. This may be due to the synergistic effect of fiber orientation and silicone modifiers to form a microscopic surface structure.

[0255] 6. Environmental adaptability: Test results show that the flowerpot of the present invention maintains good performance stability under different environmental conditions (such as high humidity and temperature fluctuations). This wide range of environmental adaptability is the result of the combined effect of plant fibers, composite binders and manufacturing process optimization, which makes it possible to apply the product under different climatic conditions.

[0256] Through the synergistic effect of multiple innovative points, the present invention not only achieves the expected performance improvement, but also produces multiple unexpected technical effects. These effects together constitute a high-performance, environmentally friendly, and multifunctional plant fiber molded flower pot system, which opens up a new way for the high-value utilization of agricultural waste and provides valuable reference for the design and application of bio-based composite materials.

[0257] The present invention also carries out the following test experiment design:

[0258] 7. High ductility test

[0259] We designed a special mold that can gradually increase the molding height, starting from 10 cm and increasing by 1 cm each time until 20 cm. We used the formulations of Examples 1-4 and Comparative Examples 1-6 for testing.

[0260] 8. Wall thickness uniformity test

[0261] For the successfully made pots with a height of 15 cm and 20 cm, we measured the wall thickness at different heights (bottom, 1 / 4 height, 1 / 2 height, 3 / 4 height and top).

[0262] 9. Longitudinal tensile strength test

[0263] Longitudinal strip samples were cut from 15 cm high flower pots and their tensile strength was tested to evaluate the bonding strength of the fibers in the vertical direction.

[0264] 10. Microstructure Analysis

[0265] Scanning electron microscopy (SEM) was used to observe the fiber arrangement and bonding at different heights in a 15 cm high flowerpot.

[0266] 11. Rheological test

[0267] Rheological tests were performed on the raw material mixture to evaluate its flow properties under high temperature and pressure.

[0268] Experimental results:

[0269] Table 3: Maximum formable height and wall thickness uniformity at 15 cm height for different formulations

[0270] sample Maximum formable height (cm) 15cm height wall thickness variation coefficient (%) Example 1 17 8.5 Example 2 19 6.2 Example 3 18 7.3 Example 4 20 5.1 Comparative Example 1 11 - Comparative Example 2 14 - Comparative Example 3 13 - Comparative Example 4 16 9.8 Comparative Example 5 12 - Comparative Example 6 15 12.5

[0271] Note: Coefficient of variation of wall thickness = (standard deviation / average wall thickness) × 100%. The smaller the value, the more uniform the wall thickness.

[0272] Table 4: Longitudinal tensile strength and rheological parameters of 15 cm high flower pots

[0273] sample Longitudinal tensile strength (MPa) Apparent viscosity (Pa·s) Shear Thinning Index Example 1 12.3 4500 0.65 Example 2 14.8 4200 0.71 Example 3 13.5 4300 0.68 Example 4 15.6 3900 0.73 Comparative Example 6 9.2 5100 0.58

[0274] Experimental results analysis and discussion:

[0275] 1. High ductility:

[0276] Examples 1-4 all successfully raised the extended height of the cylindrical basin to more than 15 cm, and Example 4 even reached 20 cm. In contrast, Comparative Examples 1-5 all failed to reach a height of 15 cm, and Comparative Example 6 barely reached 15 cm but with poor wall thickness uniformity. This result fully verifies the breakthrough achievement of the present invention in solving the problem that plant fibers cannot be stretched and formed.

[0277] 2. Wall thickness uniformity: Examples 2 and 4 showed the best wall thickness uniformity, with the wall thickness variation coefficients at a height of 15 cm being 6.2% and 5.1% respectively. This shows that the formula and process of the present invention can not only achieve high ductility, but also ensure molding quality. Although Comparative Example 6 also reached a height of 15 cm, its wall thickness variation coefficient was as high as 12.5%, indicating that the molding quality was poor.

[0278] 3. Longitudinal tensile strength: The longitudinal tensile strength of Examples 1-4 is significantly higher than that of Comparative Example 6, with Example 4 reaching 15.6 MPa. This indicates that the formula and process of the present invention significantly improve the bonding strength of the fiber in the vertical direction, which is one of the key factors in achieving high ductility.

[0279] 4. Rheological parameters: The apparent viscosity of Examples 1-4 is lower than that of Comparative Example 6, and the shear thinning index is higher. This means that under high temperature and high pressure, the mixture of the present invention has better fluidity, which is conducive to uniform distribution and filling of the material in the mold.

[0280] 5. Microstructure analysis: SEM observation results show that the fiber arrangement at different heights of Examples 1-4 is more uniform and the fibers are more tightly bound. In particular, at a height of 15 cm, obvious fiber orientation can still be observed, which is closely related to the application of fiber orientation technology.

[0281] The mechanism of the present invention for achieving high extension is explained as follows:

[0282] 1. Optimized fiber length: The present invention uses plant fibers with a length of 2-10 mm, which not only ensures sufficient mechanical strength but also does not excessively increase the viscosity of the material. Fibers of this length can form a network structure during the molding process and provide sufficient support.

[0283] 2. Composite binder system: The composite use of modified urea-formaldehyde resin, epoxy resin and polyvinyl alcohol creates a multi-scale cross-linked network. Among them, the modified urea-formaldehyde resin provides the main bonding strength, the epoxy resin increases the toughness and fluidity of the system, and the polyvinyl alcohol improves the interface bonding between the fiber and the resin. This composite system not only improves the overall strength of the material, but also significantly improves its rheological properties.

[0284] 3. Fiber orientation technology: By applying an alternating magnetic field during the molding process, the fibers are oriented in a certain direction in the vertical direction. This orientation not only improves the longitudinal tensile strength, but also helps the flow and filling of the material in the mold.

[0285] 4. Gradient density molding: The bottom uses a higher density compaction rod, while the top uses a lower density compaction rod. This design creates a density gradient from bottom to top. This helps the material flow gradually upward during the molding process, while ensuring the strength of the bottom and the ductility of the top.

[0286] 5. Innovative mold design: The design of the variable-section spiral groove increases the friction between the inner wall of the mold and the material, promoting the upward flow of the material. At the same time, the gradual design of the spiral angle and pitch ensures that the material is subjected to uniform pressure distribution during the molding process.

[0287] 6. Optimized molding process: The segmented pressurization and temperature control scheme matches the rheological properties of the material. The initial low pressure stage allows the material to fully soften and flow, while the subsequent high pressure stage ensures full compaction and cross-linking of the material.

[0288] In summary, the present invention successfully extends the height of plant fiber molded flower pots to 15 cm and above through the synergistic effect of multiple innovative points. The optimized fiber length and composite binder system provide the material basis for high extension, the fiber orientation technology and gradient density molding method improve the longitudinal strength and fluidity of the material, and the innovative mold design and molding process ensure that these advantages can be realized in actual production. The combined effect of these factors not only solves the technical problem that plant fibers cannot be stretched and molded, but also opens up new possibilities for the high-value application of bio-based composite materials.

[0289] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

[0290] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto; any person familiar with the art who, within the scope disclosed by the present invention, makes substitutions or changes based on the scheme and improved concepts of the present invention shall be covered within the protection scope of the present invention.

Claims

1. A plant fiber molded flowerpot, characterized in that: The flower pot is made of the following components in parts by weight: 80-90 parts of plant fiber; Composite adhesive 10-20 parts; Wherein, the plant fiber comprises at least one of rice straw and wheat straw with a length of 5-10 mm; The composite binder comprises the following components in parts by weight: 60-80 parts of modified urea-formaldehyde resin; Epoxy resin 15-25 parts; Polyvinyl alcohol 5-15 parts.

2. The plant fiber molded flowerpot according to claim 1, characterized in that: The flowerpot also includes the following additives: Based on the total weight of plant fiber and composite binder, 0.5-1% calcium stearate; 0.3-0.5% silane coupling agent; 0.1-0.2% dicumyl peroxide.

3. The plant fiber molded flowerpot according to claim 1, characterized in that: The molecular weight of the modified urea-formaldehyde resin is 3000-5000, the molecular weight of the epoxy resin is 700-1000, the hydrolysis degree of the polyvinyl alcohol is 87-89%, and the molecular weight is 44000-48000.

4. The plant fiber molded flowerpot according to claim 1, characterized in that: The height of the flowerpot is not less than 15 cm.

5. The method for manufacturing a plant fiber molded flowerpot according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) Plant fiber pretreatment: First, cut the plant fiber into 2-10 mm length; Secondly, soak in 1-3% NaOH solution at 60-70℃ for 2-4 hours; Then, rinse with clean water until neutral; Finally, dry to a moisture content of 5-8%; (2) Formula mixing: uniformly mixing the pretreated plant fibers with the composite binder and the additives; (3) Compression molding: After the mixture is obtained, it is loaded into a mold for compression molding.

6. The manufacturing method according to claim 5, characterized in that: The compression molding step comprises: (1) Preheating stage: Preheat the mixture to 60-70°C for 3-5 minutes and pre-compact at 0.5MPa; (2) Main pressure stage: First, maintain the pressure at 1.5 MPa for 30 seconds; Secondly, increase the pressure to 2.5MPa and maintain for 60 seconds; Again, increase the pressure to 3 MPa and maintain for 120 seconds; (3) Demolding stage: Cool down to 100°C at a rate of 2°C / min; Then, maintain a pressure of 0.5 MPa for 5 minutes for post-curing; Finally, 0.6-0.8MPa compressed air was used to assist demoulding.

7. The manufacturing method according to claim 6, characterized in that: The temperature control of the main pressure stage is: First, the starting temperature is 130°C; Secondly, the temperature was raised to 160°C at a rate of 5°C / min; Then, the temperature was maintained at 160°C until the molding was completed.

8. The manufacturing method according to claim 5, characterized in that: The mold comprises: Inner wall structure: adopts variable cross-section spiral groove design, with a top groove depth of 1.5mm and a bottom groove depth of 0.5mm; the spiral groove angle gradually decreases from 45° at the top to 30° at the bottom; the pitch gradually decreases from 15mm at the top to 8mm at the bottom; Bottom structure: There is a protrusion in the center, the diameter of which is 1 / 3 of the diameter of the bottom of the mold, the height is 5-8mm, and the edge of the protrusion is designed to be an angle of 45°.

9. The manufacturing method according to claim 5, characterized in that: Also includes a fiber orientation step: Install electromagnetic coils on the bottom and side walls of the mold; During the preheating stage, a low-frequency alternating current of 10-20 Hz is introduced; The magnetic field strength generated by the alternating current is 0.1-0.2 Tesla.

10. The manufacturing method according to claim 5, characterized in that: Also includes gradient density molding steps: The density of the bottom of the mold is 7-8 pieces / cm 2 The compaction rod; The density of the top of the mold is 5-6 pieces / cm 2 The compaction rod; Wherein, the modified urea-formaldehyde resin in the composite adhesive further contains 5-8% of a flexible epoxy resin, and the molecular weight of the flexible epoxy resin is 500-700; Furthermore, the composite adhesive further comprises 1-2% of an organic silicon modifier.

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