Biodegradable seedling raising tray and preparation method thereof

Abstract

The invention provides a biodegradable seedling raising tray and a preparation method thereof.The preparation method comprises the following steps that 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of compatilizer and 1-2 parts of coupling agent are put into a high-speed mixer to be mixed to form a mixture; slowly adding 3-8 parts of a urea aqueous solution into the mixture, and uniformly mixing to form a mixed raw material; putting the mixed raw material into a double-screw extruder, extruding, cooling and pelletizing to obtain master batch particles; and putting the master batch particles into an injection molding machine, and carrying out injection molding to form the biodegradable seedling raising tray. The prepared biodegradable seedling raising plate has the advantages of being convenient to produce, good in seedling raising effect, degradable and free of environmental pollution.

Description

Technical Field

[0001] The invention relates to the technical field of biodegradable materials, and more specifically to a biodegradable seedling tray and a preparation method thereof. Background Art

[0002] With the continuous improvement of scientific and technological levels, agricultural planting is gradually developing towards industrialization and industrialization. The cultivation of seedlings of fruits, vegetables and flowers can reduce the use of seeds, improve land utilization, increase the multiple cropping index, and create higher economic benefits. It is a planting method currently commonly used by farmers.

[0003] Seedling trays are one of the essential tools for raising crop seedlings. They are conducive to mechanized production, standardized management, labor cost savings, and long-distance transportation. They can also control root growth, reduce seedling acclimatization time, and increase crop survival rate. A seedling tray with excellent performance and reasonable design can make crop planting more efficient.

[0004] Traditional petroleum-based seedling trays are mostly made of polyethylene or polyvinyl chloride, which are odorless and non-toxic, have good chemical stability, high rigidity, hardness and strength, strong radiation resistance, mature and complete production systems, and low cost. However, due to its strong water resistance, it will hinder the seedlings from absorbing external water and limit the growth of seedlings. For crop growers, most of them need to take the cultivated seedlings out of the seedling tray one by one and then transplant them into the planting soil. This process is labor-intensive and easy to cause damage to the roots of the seedlings, making their growth state worse, reducing the survival rate, and causing certain economic losses. In addition, traditional seedling trays are non-degradable and will cause certain pollution to the environment.

[0005] Among degradable materials, pulp materials have poor wet strength and are easily damaged in a humid seedling environment; aliphatic polyester degradable materials degrade slowly, and if they cannot be degraded in time after transplanting with trays, it will affect the normal growth and development of seedlings; plant fiber seedling trays are common agricultural materials with low costs, but the output and acquisition of raw materials also limit their production scale and production areas. In the processing process, most of them need to undergo complex pre-treatment of plant fibers or use high temperature and high pressure production processes to ensure the quality of the seedling trays, which is not convenient enough in industrial production.

[0006] In summary, there is currently a lack of a seedling tray that is convenient to produce, has good seedling raising effects, is degradable, and does not pollute the environment. Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] The technical problem to be solved by the present invention is that the existing seedling trays have the problems of inconvenient production, poor seedling raising effect, non-degradability and environmental pollution.

[0009] (II) Technical solution

[0010] To achieve the above object, the technical solution adopted by the present invention is:

[0011] In a first aspect, the present invention provides a method for preparing a biodegradable seedling tray, comprising the following steps:

[0012] Put 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of compatibilizer, and 1-2 parts of coupling agent into a high-speed mixer to form a mixture;

[0013] Slowly add 3-8 parts of urea aqueous solution to the mixture and mix well to form a mixed raw material;

[0014] The mixed raw materials are put into a twin-screw extruder, extruded, cooled and pelletized to obtain masterbatch particles;

[0015] The master batch particles are put into an injection molding machine to form a biodegradable seedling tray through injection molding.

[0016] Preferably, the preparation method of the urea aqueous solution is as follows:

[0017] Mix equal amounts of pure water and urea at room temperature and stir until all urea crystals are dissolved to obtain a clear urea aqueous solution.

[0018] Preferably, the corn starch is activated high-amylose corn starch.

[0019] Preferably, the mixed raw material is put into a twin-screw extruder, extruded, cooled and pelletized to obtain masterbatch particles, which specifically includes the following steps:

[0020] The mixed raw materials are put into a twin-screw extruder, the extrusion temperature is set to 150-160°C, and the temperature of the front conveying section is set to below 80°C, the speed of the twin-screw extruder is set to 180-250r / min, the weight loss feed rate is 15-30kg / h, extrusion cooling and pelletizing are performed, and vacuum is drawn during the extrusion process, and the vacuum degree is 0.06-0.08MPa.

[0021] Preferably, the step of placing the master batch particles into an injection molding machine and injection molding the biodegradable seedling tray specifically comprises the following steps:

[0022] Put the masterbatch particles into the injection molding machine, set the injection temperature to 145-185°C, the injection pressure to 35-70 bar, the injection speed to 15%-50%, the holding pressure to 30-50 bar, the holding time to 0.5-2 minutes, and continuously inject to form a biodegradable seedling tray.

[0023] Preferably, the step of adding 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of compatibilizer, and 1-2 parts of coupling agent into a high-speed mixer to mix to form a mixture specifically comprises the following steps:

[0024] Put 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of compatibilizer, and 1-2 parts of coupling agent into a high-speed mixer and mix at a speed of 150 r / min for 2 minutes at room temperature.

[0025] Preferably, slowly adding 3-8 parts of urea aqueous solution to the mixture and mixing them evenly to form a mixed raw material specifically comprises the following steps:

[0026] Slowly add 3-8 parts of the prepared urea aqueous solution into the mixture, and continue mixing at a speed of 300 r / min for 3 minutes at room temperature.

[0027] In a second aspect, the present invention further provides a biodegradable seedling tray, which is prepared by the method for preparing a biodegradable seedling tray described in any one of the above technical solutions.

[0028] (III) Beneficial effects

[0029] The above technical solution of the present invention has at least the following advantages:

[0030] In the present invention, PBS degradable resin is used as the main material for forming the seedling tray, so that the seedling tray itself has a structural strength that meets the use requirements, and the material can be degraded in the natural environment, which is environmentally friendly; corn starch is added to the components, and the corn starch can accelerate the degradation rate of the seedling tray; further, the corn starch preferably uses activated high-amylose corn starch with better thermoplasticity, so that it can be better integrated with the PBS degradable resin, and the addition of urea aqueous solution as a plasticizer promotes this process; the present invention selects urea and water as two raw materials to prepare the plasticizer, which are cheap and easy to obtain. The two are first mixed, which can effectively reduce urea crystals in the finished product. Urea is easily soluble in water, and the mixing of the two is very simple; the seedling tray can be formed by injection molding or blow molding, and the processing process and equipment are simple and the processing time is short; the seedling tray prepared by the present invention is used for seedling cultivation, and the seedling tray can be degraded in the soil without affecting the growth of plant roots. The substances produced by degradation are not only harmless, but also can be used as nutrients to make the land more fertile and help the growth of plants. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 It is a schematic flow chart of a method for preparing a biodegradable seedling tray provided in an embodiment of the present invention.

[0033] Figure 2 It is a specific implementation flow chart of the method for preparing the biodegradable seedling tray provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0035] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly located on the other element or indirectly located on the other element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or indirectly connected to the other element.

[0036] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention, and do not indicate that a device or element must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0037] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating relative importance or indicating the number of technical features. In the description of the present invention, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. The specific implementation of the present invention is described in more detail below in conjunction with specific embodiments:

[0038] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a method for preparing a biodegradable seedling tray, comprising the following steps:

[0039] S1. Put 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of compatibilizer, and 1-2 parts of coupling agent into a high-speed mixer to form a mixture;

[0040] S2. Slowly add 3-8 parts of urea aqueous solution to the mixture and mix well to form a mixed raw material;

[0041] S3, putting the mixed raw materials into a twin-screw extruder, extruding, cooling and pelletizing to obtain masterbatch particles;

[0042] S4. Put the masterbatch particles into an injection molding machine to form a biodegradable seedling tray through injection molding.

[0043] In one embodiment, the preparation method of urea aqueous solution is as follows:

[0044] Mix equal amounts of pure water and urea at room temperature and stir until all urea crystals are dissolved to obtain a clear urea aqueous solution.

[0045] In one embodiment, the corn starch is activated high amylose corn starch.

[0046] In one embodiment, the mixed raw material is put into a twin-screw extruder, extruded, cooled and pelletized to obtain masterbatch particles, which specifically includes the following steps:

[0047] The mixed raw materials are put into a twin-screw extruder, the extrusion temperature is set to 150-160°C, and the temperature of the front conveying section is set to below 80°C, the speed of the twin-screw extruder is set to 180-250r / min, the weight loss feed rate is 15-30kg / h, extrusion cooling and pelletizing are performed, and vacuum is drawn during the extrusion process, and the vacuum degree is 0.06-0.08MPa.

[0048] In one embodiment, the master batch particles are put into an injection molding machine, and injection molding is performed to form a biodegradable seedling tray, which specifically includes the following steps:

[0049] Put the masterbatch particles into the injection molding machine, set the injection temperature to 145-185°C, the injection pressure to 35-70 bar, the injection speed to 15%-50%, the holding pressure to 30-50 bar, the holding time to 0.5-2 minutes, and continuously inject to form a biodegradable seedling tray.

[0050] In one embodiment, 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of compatibilizer, and 1-2 parts of coupling agent are put into a high-speed mixer to mix to form a mixture, which specifically includes the following steps:

[0051] Put 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of compatibilizer, and 1-2 parts of coupling agent into a high-speed mixer and mix at a speed of 150 r / min for 2 minutes at room temperature.

[0052] In one embodiment, 3-8 parts of urea aqueous solution are slowly added to the mixture and mixed evenly to form a mixed raw material, which specifically includes the following steps:

[0053] Slowly add 3-8 parts of the prepared urea aqueous solution into the mixture and continue mixing at 300 r / min for 3 minutes at room temperature.

[0054] An embodiment of the present invention further provides a biodegradable seedling tray, which is prepared by using the preparation method of the biodegradable seedling tray in any one of the above embodiments.

[0055] The seedling raising tray prepared by the embodiment of the present invention is beige or brown in color according to different process steps, has no irritating odor, has a structural strength that meets the use requirements, and has a processing rate of more than 95%.

[0056] The seedling tray prepared in this embodiment is placed in a constant temperature and humidity chamber with a humidity of 60%, and the seedling tray loses its structural strength after 5-7 days; after being buried in normal temperature and humidity soil for 30 days, the seedling tray can be mostly degraded, basically meeting the requirements of transplanting with pots. The seedling tray can be degraded in the soil without affecting the growth of plant roots, and the substances produced by degradation are not only harmless, but can also be used as nutrients to make the land more fertile and help the growth of plants.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a biodegradable seedling tray, characterized in that: The following steps are involved: Put 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of compatibilizer, and 1-2 parts of coupling agent into a high-speed mixer to form a mixture; Slowly add 3-8 parts of urea aqueous solution to the mixture and mix well to form a mixed raw material; The mixed raw materials are put into a twin-screw extruder, extruded, cooled and pelletized to obtain masterbatch particles; The master batch particles are put into an injection molding machine to form a biodegradable seedling tray through injection molding.

2. The method for preparing the biodegradable seedling tray according to claim 1, characterized in that: The preparation method of the urea aqueous solution is as follows: Mix equal amounts of pure water and urea at room temperature and stir until all urea crystals are dissolved to obtain a clear urea aqueous solution.

3. The method for preparing the biodegradable seedling tray according to claim 1, characterized in that: The corn starch is activated high-amylose corn starch.

4. The method for preparing the biodegradable seedling tray according to claim 1, characterized in that: The mixed raw material is put into a twin-screw extruder, extruded, cooled and pelletized to obtain masterbatch particles, which specifically includes the following steps: The mixed raw materials are put into a twin-screw extruder, the extrusion temperature is set to 150-160°C, and the temperature of the front conveying section is set to below 80°C, the speed of the twin-screw extruder is set to 180-250r / min, the weight loss feed rate is 15-30kg / h, extrusion cooling and pelletizing are performed, and vacuum is drawn during the extrusion process, and the vacuum degree is 0.06-0.08MPa.

5. The method for preparing the biodegradable seedling tray according to claim 1, characterized in that: The step of placing the master batch particles into an injection molding machine and injection molding the biodegradable seedling tray specifically comprises the following steps: Put the masterbatch particles into the injection molding machine, set the injection temperature to 145-185°C, the injection pressure to 35-70 bar, the injection speed to 15%-50%, the holding pressure to 30-50 bar, the holding time to 0.5-2 minutes, and continuously inject to form a biodegradable seedling tray.

6. The method for preparing the biodegradable seedling tray according to claim 1, characterized in that: The method comprises the following steps: putting 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of a compatibilizer, and 1-2 parts of a coupling agent into a high-speed mixer and mixing to form a mixture: Put 50-60 parts of PBS degradable resin, 35-45 parts of corn starch, 1-3 parts of compatibilizer, and 1-2 parts of coupling agent into a high-speed mixer and mix at a speed of 150 r / min for 2 minutes at room temperature.

7. The method for preparing the biodegradable seedling tray according to claim 1, characterized in that: The step of slowly adding 3-8 parts of urea aqueous solution to the mixture and mixing them evenly to form a mixed raw material specifically comprises the following steps: Slowly add 3-8 parts of the prepared urea aqueous solution into the mixture, and continue mixing at a speed of 300 r / min for 3 minutes at room temperature.

8. A biodegradable seedling tray, characterized in that: The biodegradable seedling tray is prepared by the preparation method of the biodegradable seedling tray according to any one of claims 1 to 7.

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