Method for preparing seedling raising container through self-gluing of bamboo sawdust powder

Abstract

The invention discloses a method for preparing a seedling culture container through self-gluing of bamboo sawdust powder, which comprises the following steps: step 1, adding alkali lignin, a liquefying agent and an acid catalyst into a reactor, heating, cooling the reactor to room temperature in an ice-water bath to obtain a reaction solution, adding magnesium oxide or calcium oxide into the reaction solution to neutralize the pH value of the reaction solution to 7, and filtering to obtain a filtrate; step 2, adding isocyanate into the filtrate obtained in the step 1, and mixing to obtain a mixed solution; and 3, stirring the mixed solution in the step 2 and the bamboo sawdust powder, pouring the mixture into a mold to obtain polyurethane foam, and demolding to obtain the seedling culture container. The bamboo sawdust-based seedling pot prepared by the method is excellent in degradation performance, can be directly transplanted without being removed, saves labor, reduces afforestation cost, avoids white pollution, can effectively treat 400,000 tons of waste produced by bamboo pulp enterprises every year, and improves the utilization rate of bamboo wood.

Description

Technical Field

[0001] The invention relates to the technical field of forestry seedling raising containers, in particular to a method for preparing a seedling raising container by self-gluing bamboo scraps powder. Background Art

[0002] Container seedling cultivation has become an important means of factory-based seedling cultivation in agriculture and forestry. Currently, most seedling containers are made of recycled plastic, which is difficult to degrade in the soil and pollutes the environment. At the same time, the seedlings need to be separated from the plastic seedling containers during planting, which not only increases labor input, but also easily causes root damage to the seedlings and reduces the survival rate.

[0003] The amount of bamboo chips and alkali lignin produced during the bamboo pulp preparation process is large and difficult to handle in a green way. We should make full use of the degradable properties of biomass to prepare green and environmentally friendly products and improve the utilization rate of bamboo resources. Summary of the invention

[0004] The present invention aims to solve the problems of environmental pollution caused by the use of a large number of plastic seedling pots in forestry production, and the large amount of bamboo chips and alkali lignin generated in the bamboo pulp preparation process and the difficulty in green treatment. The present invention utilizes the liquefied alkali lignin residue in the bamboo pulp production to form an adhesive component, and bonds the bamboo chip powder to form a degradable seedling container.

[0005] In order to achieve the above technical objectives, the technical solution provided by the present invention is:

[0006] A method for preparing a seedling container by self-gluing bamboo dust powder comprises the following steps:

[0007] Step 1: adding alkaline lignin, a liquefier, and an acid catalyst into a reactor, and cooling the reactor to room temperature in an ice water bath after heating to obtain a reaction solution, adding magnesium oxide or calcium oxide to the reaction solution to neutralize the reaction solution to pH 7, and then filtering to obtain a filtrate;

[0008] Step 2: adding isocyanate to the filtrate of step 1 and mixing to obtain a mixed solution;

[0009] Step 3: Take the mixed solution of step 2 and mix it with bamboo powder, then pour it into a mold to obtain polyurethane foam, and then demould it to obtain a seedling container.

[0010] Furthermore, in step 1, the components are calculated by weight as follows: 20-25 parts of alkali lignin, 70 parts of liquefier, and 5-10 parts of acid catalyst.

[0011] Furthermore, in step 1, the heating temperature is 120-180° C. and the heating time is 2-8 hours.

[0012] Furthermore, the liquefier is a mixture of polyethylene glycol-400 and glycerol in a ratio of 3:1.

[0013] Furthermore, in step 1, the acidic catalyst is concentrated sulfuric acid, phosphoric acid or solid acid.

[0014] Furthermore, in step 3, the components are 5-15 parts by weight of the mixed solution and 85-95 parts of the bamboo powder. Furthermore, the stirring time is 5-20 seconds.

[0015] Furthermore, in step 3, a release agent is coated inside the mold.

[0016] The present invention has the following beneficial effects:

[0017] The bamboo chip-based seedling container prepared by this invention has excellent degradation performance and can be directly transplanted without removal, saving labor, reducing afforestation costs, and avoiding white pollution. At the same time, it can effectively process 400,000 tons of waste generated by bamboo pulp enterprises each year and improve the utilization rate of bamboo materials. DETAILED DESCRIPTION

[0018] The technical solution of the present invention is described clearly and completely below. 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 creative work are within the scope of protection of the present invention.

[0019] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0020] Embodiment 1;

[0021] Add 20 parts of alkali lignin, 70 parts of liquefier (mixture of polyethylene glycol-400 and glycerol in a ratio of 3:1), and 5 parts of concentrated sulfuric acid into a reaction container, heat to 120°C for 2 hours, then cool the reaction container to room temperature in an ice water bath, add magnesium oxide to neutralize the reaction solution to pH 7, and then filter it. The filtrate is used for foaming to prepare a polyurethane seedling container.

[0022] Determine the hydroxyl value of the filtrate and then add isocyanate (In of PAPI) (NCO) / n (OH) 5 parts of the mixed solution were mixed with 95 parts of bamboo dust powder and stirred rapidly for 5 seconds, and then poured into a mold (the mold size was prepared as required) coated with a release agent (dimethyl silicone oil, etc.), matured at room temperature to obtain polyurethane foam, and then demolded to obtain a seedling container.

[0023] The wall of the seedling container has a breakage rate of ≤3.5% and is completely degraded after being buried in the soil for 150 days.

[0024] Embodiment 2:

[0025] Add 20 parts of alkali lignin, 70 parts of liquefier (mixture of polyethylene glycol-400 and glycerol in a ratio of 3:1), and 5 parts of phosphoric acid into a reaction container, heat to 160°C for 6 hours, then cool the reaction container to room temperature in an ice water bath, add magnesium oxide or calcium oxide to neutralize the reaction solution to pH 7, and then filter it. The filtrate is used for foaming to prepare a polyurethane seedling container.

[0026] Determine the hydroxyl value of the filtrate and then add isocyanate (In of PAPI) (NCO) / n (OH) 10 parts of the mixed solution were mixed with 90 parts of bamboo dust powder and stirred rapidly for 15 seconds, and then poured into a mold (the mold size was prepared as required) coated with a release agent (dimethyl silicone oil, etc.), matured at room temperature to obtain polyurethane foam, and then demolded to obtain a seedling container.

[0027] The wall of the seedling pot has a breakage rate of ≤2.5% and is completely degraded after being buried in the soil for 140 days.

[0028] Example 3

[0029] Add 25 parts of alkali lignin, 70 parts of liquefier (mixture of polyethylene glycol-400 and glycerol in a ratio of 3:1), and 10 parts of solid acid into a reaction container, heat to 180°C for 8 hours, then cool the reaction container to room temperature in an ice water bath, add calcium oxide to neutralize the reaction solution to pH 7, and then filter it. The filtrate is used for foaming to prepare a polyurethane seedling container.

[0030] Determine the hydroxyl value of the filtrate and then add isocyanate (In of PAPI) (NCO) / n (OH) 15 parts of the mixed solution were mixed with 85 parts of bamboo dust powder and stirred rapidly for 20 seconds, and then poured into a mold (the mold size was prepared as required) coated with a release agent (dimethyl silicone oil, etc.), matured at room temperature to obtain a polyurethane foam, and then demolded to obtain a seedling container.

[0031] The wall of the seedling container cup has a breakage rate of ≤1.5% and is completely degraded after being buried in the soil for 154 days.

[0032] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0033] The above specific implementation methods are detailed descriptions of the present invention. It cannot be determined that the specific implementation methods of the present invention are limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A method for preparing a seedling container by self-gluing bamboo dust powder, characterized in that: The steps include: Step 1: adding alkaline lignin, a liquefier, and an acid catalyst into a reactor, and cooling the reactor to room temperature in an ice water bath after heating to obtain a reaction solution, adding magnesium oxide or calcium oxide to the reaction solution to neutralize the reaction solution to pH 7, and then filtering to obtain a filtrate; Step 2: adding isocyanate to the filtrate of step 1 and mixing to obtain a mixed solution; Step 3: Take the mixed solution of step 2 and the bamboo shavings powder, stir them and pour them into a mold to obtain polyurethane foam, and then demould to obtain a seedling container.

2. The method for preparing a seedling container by self-gluing bamboo dust powder according to claim 1, characterized in that: In step 1, the components are calculated by weight as follows: 20-25 parts of alkali lignin, 70 parts of liquefier, and 5-10 parts of acid catalyst.

3. The method for preparing a seedling container by self-gluing bamboo dust powder according to claim 1, characterized in that: In the step 1, the heating temperature is 120-180° C. and the heating time is 2-8 hours.

4. The method for preparing a seedling container by self-gluing bamboo dust powder according to claim 1 or 2, characterized in that: The liquefier is a mixture of polyethylene glycol-400 and glycerol in a ratio of 3:

1.

5. The method for preparing a seedling container by self-gluing bamboo dust powder according to claim 1, characterized in that: In the step 1, the acidic catalyst is concentrated sulfuric acid, phosphoric acid or solid acid.

6. The method for preparing a seedling container by self-gluing bamboo dust powder according to claim 1, characterized in that: In the step 3, the components are calculated by weight: 5-15 parts of the mixed liquid and 85-95 parts of the bamboo powder.

7. The method for preparing a seedling container by self-gluing bamboo dust powder according to claim 1, characterized in that: The stirring time is 5-20 seconds.

8. The method for preparing a seedling raising container by self-gluing bamboo dust powder according to claim 1, characterized in that: In the step 3, a release agent is coated inside the mold.