A multi-dimensional plant growth matrix material

Abstract

The invention discloses a multidimensional plant growth matrix material, and relates to the technical field of soilless cultivation. The multidimensional plant growth matrix material disclosed in the invention is a polyurethane foam matrix for soilless cultivation, and it is a mixture white material obtained by mixing bio-oil-based polyester / polyether polyol, amine catalyst, foam stabilizer, sodium secondary alkyl sulfonate and deionized water; organic modified diatomite and cross-linking agent are mixed into a premix; polyisocyanate is added to the mixture white material, stirred for 15-25s, then dioctyltin mercaptide and premix are added sequentially, stirring is continued for 5-8s, poured into a mold for curing for 2-4h, then warmed to 60-70°C for 3-8h. The preparation method of the matrix material provided by the invention is simple and easy to operate, and the raw material is environmentally friendly, so that the matrix material obtained is biodegradable, has excellent mechanical properties and compressive strength, and has high water absorption, high water retention rate and high porosity at the same time, has a higher cation exchange capacity, and is conducive to the growth of multidimensional plants.

Description

Technical Field

[0001] The invention belongs to the technical field of soilless cultivation, and in particular relates to a hydrophilic polyurethane foam matrix material suitable for multi-dimensional plant growth and a preparation method thereof. Background Art

[0002] Three-dimensional greening can be carried out on the vertical greening of building facades such as slopes, walls, and roofs, becoming an important way to strengthen urban greening construction. However, at present, urban slope greening mainly uses geotextiles to cover the soil, and then fixes it on the slope with metal wires and rivets as a green growth matrix. This method is practical, but the operation process is cumbersome, the weather resistance is poor, and the price is high; the traditional three-dimensional greening matrix of walls, roofs, etc. is made of some soil particles mixed with some plant fibers and added with gravel and nutrient solution. Its structure is loose, requires containers, has low durability, is easy to breed pests, and has weak water retention capacity. The shortcomings limit its large-scale promotion and application in three-dimensional greening. Therefore, in view of the above shortcomings, based on the particularity of the formation of three-dimensional greening, the research and development of artificially formed soilless cultivation matrix has become a hot topic of research.

[0003] Artificially synthesized soilless cultivation with substrates is divided into inorganic substrates, organic substrates and synthetic substrates. Inorganic substrates are mineral materials such as ceramsite, gravel, perlite, vermiculite, rock wool, etc., which have high utilization rates of nutrient solution, but during the planting process, the nutrient solution and water volatilize more seriously, increasing costs; organic substrates are plant residues such as sawdust, straw, peat, rice husks and similar materials, which are rich in nutrients and pores, but the roots of plants are prone to root rot and are easily infected by bacteria and diseases, resulting in increased planting costs; synthetic substrates commonly used are urea-formaldehyde resin, phenolic resin and polyurethane foam substrates, but urea-formaldehyde foam releases toxic free formaldehyde and is brittle, phenolic foam is brittle, and residual acid pollutes the environment. Therefore, polyurethane foam is used as the main soilless cultivation substrate for three-dimensional greening due to its light weight, high open porosity, good water retention and water absorption.

[0004] Polyurethane foam contains carboxyl (-COOH), hydroxyl (-OH) and other strong hydrophilic groups. It is a polymer material with a certain degree of cross-linking. It has excellent properties such as resistance to salt water, dilute acid and alkali. During use, it will not cause changes in the chemical composition, pH, conductivity, etc. of the nutrient solution due to the stability of the matrix structure, and can maintain its stable use. Since soilless cultivation is to cultivate crops in an inactive solid matrix adsorbed with nutrient solution, the matrix must have a certain size of solid matter, good solid and supporting effects, good mechanical strength and compressive resistance; have larger pores, retain water and hydrophilicity, retain fertilizer and be breathable, and can absorb nutrient solution; stable chemical properties, do not contain harmful ingredients, do not cause qualitative changes in the nutrient solution, do not add burden to the environment, and be renewable or biodegradable. However, the existing polyurethane foam has average water-retaining and hydrophilic properties, and highly absorbent resin SAP is conventionally added to enhance its water absorption and water-retaining properties. Due to its low density, it has low strength and poor compression resistance, and is prone to collapse after a period of use. It does not react with the nutrient solution, but has no adsorption effect on the nutrient solution, and its fertilizer retention is average. The raw materials used in its preparation are petrochemical products, which makes the polyurethane foam non-recyclable and cannot be biodegraded by itself, which brings a burden to the environment and is not in line with the principle of sustainable development. Summary of the invention

[0005] The purpose of the present invention is to provide a soilless cultivation multidimensional plant growth material with polyurethane foam as a matrix and a preparation method thereof. The preparation method of the matrix material is simple and easy to operate, and the raw materials are environmentally friendly, so that the obtained matrix material is biodegradable, has excellent mechanical properties and compressive strength, and has high water absorption rate, high water retention rate and high porosity, and has a high cation exchange capacity, which is conducive to the growth of multidimensional plants.

[0006] In order to achieve the purpose of the present invention, the present invention provides a multi-dimensional plant growth matrix material, which is a polyurethane foam matrix for soilless cultivation. The material is composed of the following raw materials in parts by weight: 100 parts of natural oil-based polyester / polyether polyol, 31-50 parts of polyisocyanate, 20-40 parts of organic modified diatomaceous earth, 0.6-1.5 parts of amine catalyst, 0.2-0.4 parts of dioctyltin mercaptan, 1-3 parts of sodium secondary alkyl sulfonate, 0.3-1.5 parts of foam stabilizer, 0-1.2 parts of cross-linking agent and 1.5-3.0 parts of deionized water.

[0007] Preferably, the natural oil-based polyester / polyether polyol is a solvent-free, branched polyether / polyester polyol with a hydroxyl value ranging from 160 to 920 mg KOH / g, containing renewable and biodegradable components. The natural oil-based polyester / polyether polyol in the present invention is selected from any one or two of BASF's models Sovermol 815, Sovermol 750 or Sovermol 805. In the present invention, since the selected polyol contains renewable and biodegradable groups, compared with the polyurethane products made from traditional petrochemical products, the polyurethane foam generated by the reaction of the selected polyol, isocyanate, etc. in the present invention is renewable and biodegradable under certain conditions, which conforms to the modern environmental protection concept.

[0008] Further, the polyisocyanate is polymeric diphenylmethane diisocyanate (PMDI), which is an isomer mixture consisting of 80% 2,4-toluene diisocyanate and 20% 2,6-toluene diisocyanate (TDI). Preferably, the polyisocyanate of the present invention is BASF's Lupranate T80.

[0009] Furthermore, the preparation method of the organic modified diatomite is:

[0010] (1) Place diatomaceous earth in a 5 mol / L H2SO4 solution, stir at 60-70°C for 1 hour, filter, wash with deionized water, and dry for later use;

[0011] (2) The silane coupling agent KH-602 (i.e., N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane), ethanol and water are mixed evenly in appropriate proportions to prepare an aminosilane solution, and then the diatomaceous earth is added to the aminosilane solution, stirred at room temperature for 3-5 hours, and filtered to obtain silane-modified diatomaceous earth;

[0012] (3) Evenly mix appropriate amounts of triethanolamine soap, castor oil and water, then add ethanol, stir evenly at 60°C to obtain a transparent solution, then add the above-mentioned silane-modified diatomaceous earth into the transparent solution, stir at 60°C for 6-8h, filter, wash with deionized water, and dry to obtain organic modified diatomaceous earth.

[0013] Diatomaceous earth is non-toxic and tasteless, exists in large quantities in nature, has high purity, low cost, light weight, high porosity, strong permeability, and excellent water absorption and cation adsorption properties. However, when diatomaceous earth is directly added to polyurethane foam, it is unevenly dispersed, easy to unite, and block the pores, resulting in small and uneven pore sizes, making the polyurethane foam solid shape unstable, brittle, and reducing water absorption and water retention performance and air permeability, which is not conducive to the growth of multi-dimensional plants.

[0014] The present invention purifies diatomite and then activates it using a silane coupling agent KH-602 containing a diamino group, so that the surface of the modified diatomite contains -NH2, -OH and the like, thereby improving the surface activity of the diatomite. The activated diatomite is then further modified using a microemulsion obtained by mixing triethanolamine soap, castor oil, water and ethanol, so that the surface of the organically modified diatomite contains a large number of active functional groups such as -COOH, -OH and -NH2, thereby allowing the surface active groups of the diatomite to participate in the reaction with the polyurethane during foaming and chain growth, so that the diatomite can be uniformly dispersed in the pores of the matrix material of the present invention, and the compressive strength, water absorption rate, water retention rate and cation exchange capacity (with better adsorption) of the matrix material of the present invention are improved.

[0015] Furthermore, the diatomaceous earth is purified diatomaceous earth, and the purification adopts a roasting method, and the roasting temperature is 600-700° C., which is used to remove organic impurities in the diatomaceous earth.

[0016] Furthermore, in the step (1), the ratio of the diatomaceous earth to the H2SO4 solution is 0.02-0.05 g / mL, so as to remove impurities such as iron and aluminum in the diatomaceous earth.

[0017] Furthermore, in the step (2), the mass ratio of the silane coupling agent KH-602, ethanol and water is 1:(1-2):(3-5), and the mass ratio of the diatomaceous earth to the silane coupling agent KH-602 is 1:(0.2-0.4).

[0018] Furthermore, in step (3), the mass ratio of triethanolamine soap, castor oil, water and ethanol in the transparent solution is (1-3):1:(5-7):(2-4), and the ratio of the silane-modified diatomaceous earth to the transparent solution is 0.3-0.6 g / g.

[0019] Furthermore, the amine catalyst is composed of bis(2-dimethylaminoethyl) ether and triethanolamine in a mass ratio of 3:1. The present invention adopts a combination of bis(2-dimethylaminoethyl) ether and triethanolamine in an appropriate ratio for catalysis, has good catalytic activity for the foaming and gelling reaction of polyurethane, can effectively adjust and control the pore structure in the foaming process, so that the pore diameter of the foam of the present invention is large and uniform, and can also have a good synergistic effect with dioctyltin mercaptan, so that the organic modified diatomaceous earth can be evenly dispersed in the polyurethane foam, thereby improving the comprehensive performance of the present invention.

[0020] Further, the foam stabilizer is an organosilicon surfactant;

[0021] The cross-linking agent is diethanolamine or glycerol.

[0022] The present invention also provides a method for preparing a multidimensional plant growth matrix material, which specifically comprises the following steps:

[0023] S1. The bio-oil-based polyester / polyether polyol, amine catalyst, foam stabilizer, sodium secondary alkyl sulfonate and deionized water are uniformly mixed to obtain a white mixture;

[0024] S2. The organically modified diatomaceous earth and the crosslinking agent are mixed uniformly to obtain a premix;

[0025] S3. Add polyisocyanate to the white mixture, stir at 1000-1500 rpm for 15-25 seconds, then add dioctyltin mercaptan and the premix in sequence, continue stirring for 5-8 seconds, pour into a mold and cure for 2-4 hours, then heat to 60-70°C and mature for 3-8 hours to obtain a polyurethane foam matrix.

[0026] The present invention has achieved the following beneficial effects:

[0027] The polyurethane foam matrix of the present invention is by first rapidly foaming and reacting bio-oil-based polyester / polyether polyol and polyisocyanate in the presence of amine catalysts, foam stabilizers, deionized water and sodium secondary alkyl sulfonate, then adding organic modified diatomite, under the effects of dioctyltin mercaptide, crosslinking agent, etc., while polyurethane continues to foam and react, isocyanate, -OH, -NH2, etc. are reacted with the active groups on the surface of diatomite, and the addition time is controlled well, so that diatomite is dispersed in the pores after foaming, and is obtained after solidification and aging. The present invention, by controlling the order of addition and the time of addition, makes the matrix obtained have excellent mechanical properties and compressive strength, and simultaneously has high water absorption, high water retention rate, high porosity and higher cation exchange capacity, and is suitable for the planting, cultivation and growth of multidimensional plants.

[0028] The secondary alkyl sodium sulfonate of the present invention is an anionic surfactant. During the foaming process, the organic anion and the polymer undergo ion exchange, so that the anion is attached to the polymer surface, the surface tension of the foam is increased, and the present invention is helpful to form open-cell bubbles, and the water absorption, water retention and air permeability of the present invention are increased; at the same time, it can also be used as a foaming auxiliary agent to improve the foaming efficiency of the present invention. The present invention uses dioctyltin mercaptide with large steric hindrance, which has good stability and delayed catalytic effect, and then controls the polyurethane during the foaming process, which can fully react with the active groups on the surface of diatomaceous earth, so that the diatomaceous earth can be evenly dispersed in the pores of the present invention, and the compressive strength and adsorption air permeability of the present invention are improved. The raw materials used in the present invention are non-toxic, the matrix material has a stable structure, can be recycled and reused, and can be biodegraded. It belongs to an environmentally friendly material and meets national environmental protection requirements. The present invention can prepare soilless cultivation substrates of various shapes according to requirements. The substrates are light in weight, uniform in pores, stable in properties, form good plant growth pores, can carry nutrient solutions of various needs, and can effectively adsorb organic components and various cations in the nutrient solution to prevent them from being lost. The substrates have excellent water and fertilizer retention effects, high cation exchange capacity, and are beneficial to the growth of multi-dimensional plants. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are 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.

[0030] The multi-dimensional plant growth matrix material and the preparation method thereof of the present invention are described below in conjunction with specific embodiments.

[0031] The multi-dimensional plant growth matrix material provided in the embodiment of the present invention is a polyurethane foam matrix.

[0032] Example 1

[0033] In parts by weight, the preparation method of the polyurethane foam matrix of this embodiment 1 is:

[0034] S1. 100 parts of bio-oil-based polyester / polyether polyol, 1.5 parts of amine catalyst, 1.2 parts of foam stabilizer, 3 parts of sodium secondary alkyl sulfonate and 3 parts of deionized water were mixed to obtain a white mixture;

[0035] S2. Add 50 parts of polyisocyanate to the above mixture, stir at 1500 rpm for 15 seconds, then add 0.4 parts of dioctyltin mercaptan and 40 parts of organic modified diatomaceous earth in sequence, continue stirring for 8 seconds, pour into a mold and cure for 4 hours, then heat to 60°C and mature for 8 hours to obtain a polyurethane foam matrix.

[0036] The preparation method of the organic modified diatomite is as follows: 40g of 200-mesh calcined diatomite is placed in 1L of 5mol / LH2SO4 solution, stirred at 70°C for 1h, filtered, washed with deionized water 3 times, and dried at 120°C for standby use; 3g of silane coupling agent KH-602, 6g of ethanol and 12g of deionized water are mixed evenly to prepare an aminosilane solution, and then the above 10g of diatomite is added to the aminosilane solution, stirred at room temperature for 4h, filtered, and silane-modified diatomite is obtained; 3g of triethanolamine soap, 1g of castor oil and 5g of water are mixed evenly, and then 3g of ethanol is added, stirred evenly at 60°C to obtain a transparent solution, and then the above 5g of silane-modified diatomite is put into 10g of the transparent solution, stirred at 60°C for 6h, filtered, washed with deionized water twice, and dried.

[0037] The bio-oil-based polyester / polyether polyol is selected from BASF's Sovermol 750;

[0038] The amine catalyst is composed of bis(2-dimethylaminoethyl) ether and triethanolamine in a mass ratio of 3:1;

[0039] The foam stabilizer is selected from Dow Corning DC-29 silicone polyether surfactant;

[0040] The above-mentioned sodium secondary alkyl sulfonate is selected from Clariant's Wehylclean SAS 60;

[0041] The polyisocyanate is polymeric diphenylmethane diisocyanate (PMDI), selected from BASF's Lupranate T80;

[0042] The above-mentioned dioctyltin mercaptan is selected from Xindian Chemical;

[0043] The above triethanolamine soap is triethanolamine oleate soap, which is provided by Tesco Chemicals;

[0044] The above castor oil is provided by Jinan Nochuang Chemical.

[0045] Example 2

[0046] By weight, the preparation method of the polyurethane foam matrix of this embodiment 2 is:

[0047] S1. 100 parts of bio-oil-based polyester / polyether polyol, 0.6 parts of amine catalyst, 0.7 parts of foam stabilizer, 1.2 parts of sodium secondary alkyl sulfonate and 1.5 parts of deionized water were mixed to obtain a mixture of white material;

[0048] S2. 25 parts of organically modified diatomaceous earth and 1 part of diethanolamine were mixed to obtain a premix;

[0049] S3. Add 31 parts of polyisocyanate to the white mixture, stir at 1000 rpm for 15 seconds, then add 0.2 parts of dioctyltin mercaptan and the premix in sequence, continue stirring for 8 seconds, pour into a mold and cure for 2 hours, then heat to 70°C and mature for 5 hours to obtain a polyurethane foam matrix.

[0050] The preparation method of the organic modified diatomite is as follows: 40g of 200-mesh calcined diatomite is placed in 1L of 5mol / LH2SO4 solution, stirred at 70°C for 1h, filtered, washed with deionized water 3 times, and dried at 120°C for standby use; 4g of silane coupling agent KH-602, 8g of ethanol and 15g of deionized water are mixed evenly to prepare an aminosilane solution, and then the above 10g of diatomite is added to the aminosilane solution, stirred at room temperature for 4h, filtered, and silane-modified diatomite is obtained; 3g of triethanolamine soap, 1g of castor oil and 5g of water are mixed evenly, and then 3g of ethanol is added, stirred evenly at 60°C to obtain a transparent solution, and then the above 6g of silane-modified diatomite is put into the 10g transparent solution, stirred at 60°C for 6h, filtered, washed with deionized water twice, and dried.

[0051] The bio-oil-based polyester / polyether polyol is selected from BASF's Sovermol 805;

[0052] The above-mentioned amine catalyst, foam stabilizer, sodium secondary alkyl sulfonate, polyisocyanate, dioctyltin mercaptan, triethanolamine soap and castor oil are the same as those in Example 1, and specific reference is made to Example 1.

[0053] Example 3

[0054] In parts by weight, the preparation method of the polyurethane foam matrix of this embodiment 3 is:

[0055] S1. 100 parts of bio-oil-based polyester / polyether polyol, 1.2 parts of amine catalyst, 1.5 parts of foam stabilizer, 2.3 parts of sodium secondary alkyl sulfonate and 2.4 parts of deionized water were mixed to obtain a mixture of white material;

[0056] S2. 20 parts of organically modified diatomaceous earth and 1.2 parts of diethanolamine were mixed to obtain a premix;

[0057] S3. Add 42 parts of polyisocyanate to the above mixture, stir at 1000 rpm for 20 seconds, then add 0.3 parts of dioctyltin mercaptan and the above premix in sequence, continue stirring for 8 seconds, pour into a mold and cure for 3 hours, then heat to 70°C and mature for 6 hours to obtain a polyurethane foam matrix.

[0058] The preparation method of the organic modified diatomite is as follows: 40g of 200-mesh calcined diatomite is placed in 1L of 5mol / LH2SO4 solution, stirred at 70°C for 1h, filtered, washed with deionized water 3 times, and dried at 120°C for standby use; 3g of silane coupling agent KH-602, 5g of ethanol and 12g of deionized water are mixed evenly to prepare an aminosilane solution, and then the above 10g of diatomite is added to the aminosilane solution, stirred at room temperature for 4h, filtered, and silane-modified diatomite is obtained; 3g of triethanolamine soap, 1g of castor oil and 5g of water are mixed evenly, and then 4g of ethanol is added, stirred evenly at 60°C to obtain a transparent solution, and then the above 5g of silane-modified diatomite is put into 10g of the transparent solution, stirred at 60°C for 6h, filtered, washed with deionized water twice, and dried.

[0059] The bio-oil-based polyester / polyether polyol is selected from BASF's Sovermol 815;

[0060] The above-mentioned amine catalyst, foam stabilizer, crosslinking agent, sodium secondary alkyl sulfonate, polyisocyanate, dioctyltin mercaptan, triethanolamine soap and castor oil are the same as those in Example 1, and specific reference is made to Example 1.

[0061] Example 4

[0062] In terms of parts by weight, the preparation method of the polyurethane foam matrix of this embodiment 4 is the same as that of embodiment 3 in terms of raw materials and specific steps, and specific reference is made to embodiment 3. The difference is that the addition amount of the organically modified diatomaceous earth in this embodiment 4 is modified to 32 parts.

[0063] Example 5

[0064] In terms of parts by weight, the preparation method of the polyurethane foam matrix of this Example 5 is the same as that of Example 3 in terms of raw materials and specific steps, and specific reference is made to Example 3. The difference is that the amount of organically modified diatomaceous earth added in this Example 4 is modified to 40 parts.

[0065] Comparative Example 1

[0066] The components and preparation method of the polyurethane foam matrix of this comparative example are the same as those in Example 4, and specific reference is made to Example 4. The difference is that the diatomite in this comparative example is not modified by using a microemulsion, that is, silane-modified diatomite is added in this comparative example, and its preparation method is as follows: 40 g of 200-mesh calcined diatomite is placed in 1 L of 5 mol / L H2SO4 solution, stirred at 70°C for 1 hour, filtered, washed with deionized water 3 times, and dried at 120°C for standby use; 3 g of silane coupling agent KH-602, 5 g of ethanol and 12 g of deionized water are mixed evenly to prepare an aminosilane solution, and then the above 10 g of diatomite is added to the aminosilane solution, stirred at room temperature for 4 hours, filtered, and silane-modified diatomite is obtained.

[0067] Comparative Example 2

[0068] The components and preparation method of the polyurethane foam matrix of this comparative example are the same as those in Example 4, and specific reference is made to Example 4. The difference is that the diatomaceous earth in this comparative example is not modified with aminosilane, that is, the diatomaceous earth modified with microemulsion is added in this comparative example, and its preparation method is as follows: 40g of 200-mesh calcined diatomaceous earth is placed in 1L of 5mol / L H2SO4 solution, stirred at 70°C for 1h, filtered, washed with deionized water 3 times, and dried at 120°C for standby use; 3g of triethanolamine soap, 1g of castor oil and 5g of water are mixed evenly, and then 4g of ethanol is added, stirred evenly at 60°C to obtain a transparent solution, and then the above 5g of acid-treated standby diatomaceous earth is put into 10g of the transparent solution, stirred at 60°C for 6h, filtered, washed with deionized water 2 times, and dried.

[0069] Comparative Example 3

[0070] The components and preparation method of the polyurethane foam matrix of this comparative example are the same as those of Example 4, and specific reference is made to Example 4. The difference is that the diatomaceous earth in this comparative example is not modified by aminosilane and microemulsion, that is, the diatomaceous earth added in this comparative example is purified, and the preparation method is as follows: 40 g of calcined diatomaceous earth with 200 mesh is placed in 1 L of 5 mol / L H2SO4 solution, stirred at 70°C for 1 hour, filtered, washed with deionized water 3 times, and dried at 120°C for use.

[0071] Comparative Example 4

[0072] The components and preparation method of the polyurethane foam matrix of this comparative example are the same as those in Example 4, and specific reference is made to Example 4. The difference is that no organic modified diatomaceous earth is added to this comparative example, and its preparation method is a conventional one-step method, that is: 100 parts of bio-oil-based polyester / polyether polyol, 1.2 parts of amine catalyst, 1.5 parts of foam stabilizer, 1.2 parts of diethanolamine, 0.3 parts of dioctyltin mercaptide, 2.3 parts of sodium secondary alkyl sulfonate and 2.4 parts of deionized water are mixed uniformly to obtain a mixture white material; 42 parts of polyisocyanate are added to the above mixture white material, stirred at 1000 rpm for 28 seconds, poured into a mold for curing for 3 hours, and then heated to 70°C for aging for 6 hours.

[0073] Comparative Example 5

[0074] The components and preparation method of the polyurethane foam matrix of this comparative example are the same as those of Example 4, and specific reference is made to Example 4. The difference is that dioctyltin mercaptan is not added in this comparative example, but stannous octoate is used to replace dioctyltin mercaptan.

[0075] Comparative Example 6

[0076] The components and preparation method of the polyurethane foam matrix of this comparative example are the same as those in Example 4, and specific reference is made to Example 4. The difference is that in this comparative example, no secondary alkyl sulfonate sodium is added, but a cell opener Q100-A is added to replace the secondary alkyl sulfonate sodium, which is selected from Shanghai Qiguang.

[0077] Comparative Example 7

[0078] The components of the polyurethane foam matrix of this comparative example and the raw materials and preparation methods of the components are the same as those in Example 4, and specific reference is made to Example 4. The difference is that the preparation method of the polyurethane foam matrix of this comparative example is different, which is specifically as follows: by weight, the preparation method of the polyurethane foam matrix of Example 3 is: 100 parts of bio-oil-based polyester / polyether polyol, 1.2 parts of amine catalyst, 1.5 parts of foam stabilizer, 32 parts of organic modified diatomaceous earth, 1.2 parts of diethanolamine, 0.3 parts of dioctyltin mercaptide, 2.3 parts of sodium secondary alkyl sulfonate and 2.4 parts of deionized water are mixed uniformly to obtain a mixture white material; 42 parts of polyisocyanate are added to the above mixture white material, stirred at 1000 rpm for 28 seconds, poured into a mold for curing for 3 hours, and then heated to 70°C for aging for 6 hours to obtain a polyurethane foam matrix.

[0079] The density, compression strength, water absorption rate, water retention rate, open porosity, cation exchange capacity and other properties of the polyurethane foam matrix (i.e., multidimensional plant growth matrix material) prepared in the above Examples 1-5 and Comparative Examples 1-7 were tested, and the test results are shown in Tables 1 and 2 below.

[0080] Density: Tested according to GB / T6343-2009, the sample is made into a size of 50 mm×50 mm×50 mm, the size is accurately measured with a vernier caliper, the mass is weighed with a balance, and the density is calculated.

[0081] Compression strength: tested in accordance with GB / T8813-2008.

[0082] Water absorption:

[0083] Cut a sample of 1g, soak it in water for 1d, use a filter to absorb excess water on the surface and weigh it, and use the following formula to calculate the foam water absorption rate:

[0084]

[0085] Water retention rate:

[0086] Cut a sample with a mass of 1 g, soak it in water for 1 day to fully absorb water, mix it with 3 times the mass of dry soil, put it into a cloth bag and put it into a container, fill and cover it with about 100 mm of soil with dry soil, dry it in an oven at 50°C for 1 day, and then weigh the mass of the soil in the bag.

[0087] Use the following formula to calculate foam water retention:

[0088]

[0089] Cation exchange capacity: According to GB 7863-1987 National Standard for Determination of Cation Exchange Capacity of Forest Soil (GB), in the actual test process, the sample was modified to the polyurethane foam matrix of the present invention and 5 g was weighed, and the other steps were the same.

[0090] Table 1 Test results of polyurethane foam matrix properties obtained in Examples and Comparative Examples

[0091]

[0092] According to the test results of Table 1 above, it can be seen that the multidimensional plant growth matrix material of the present invention is light in weight and has relatively excellent compressive strength, hydrophilicity, water retention, porosity and cation exchange capacity. The use of the organic modified diatomite of the present invention, that is, the diatomite is activated by aminosilane and then modified by microemulsion, significantly improves the compressive resistance, hydrophilicity, water retention, porosity and cation exchange capacity of the present invention; the use of dioctyltin mercaptan significantly improves the compressive resistance and hydrophilic water retention of the present invention; the use of anionic surfactants significantly improves the porosity of the present invention, which is beneficial to the improvement of the hydrophilic water retention performance of the matrix material; the use of a certain feeding sequence and feeding time can significantly improve the compressive strength, hydrophilicity, water retention, porosity and cation exchange capacity of the present invention.

[0093] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0094] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A multidimensional plant growth matrix material, which is a polyurethane foam matrix for soilless cultivation, characterized in that: The invention is composed of the following raw materials in parts by weight: 100 parts of natural oil-based polyester / polyether polyol, 31-50 parts of polyisocyanate, 20-40 parts of organic modified diatomaceous earth, 0.6-1.5 parts of amine catalyst, 0.2-0.4 parts of dioctyltin mercaptan, 1-3 parts of sodium secondary alkyl sulfonate, 0.3-1.5 parts of foam stabilizer, 0-1.2 parts of crosslinking agent and 1.5-3.0 parts of deionized water; The preparation method of the polyurethane foam matrix specifically comprises the following steps: S1. The bio-oil-based polyester / polyether polyol, amine catalyst, foam stabilizer, sodium secondary alkyl sulfonate and deionized water are uniformly mixed to obtain a white mixture; S2. The organically modified diatomaceous earth and the crosslinking agent are mixed uniformly to obtain a premix; S3. The polyisocyanate is added to the white mixture, stirred at 1000-1500rpm for 15-25s, and then dioctyltin mercaptan and the premix are added in sequence, stirring is continued for 5-8s, poured into a mold and cured for 2-4h, and then heated to 60-70°C for aging for 3-8h to obtain a polyurethane foam matrix; The preparation method of the organic modified diatomaceous earth is: (1) Place diatomaceous earth in a 5 mol / L H2SO4 solution, stir at 60-70°C for 1 hour, filter, wash with deionized water, and dry for later use; (2) The silane coupling agent KH-602, ethanol and water are mixed evenly in an appropriate ratio to prepare an aminosilane solution, and then the diatomaceous earth is added to the aminosilane solution, stirred at room temperature for 3-5 hours, and filtered to obtain silane-modified diatomaceous earth; (3) Evenly mix appropriate amounts of triethanolamine soap, castor oil and water, then add ethanol, stir evenly at 60°C to obtain a transparent solution, then add the above-mentioned silane-modified diatomaceous earth into the transparent solution, stir at 60°C for 6-8h, filter, wash with deionized water, and dry to obtain organic modified diatomaceous earth.

2. The multidimensional plant growth matrix material according to claim 1, characterized in that: The polyisocyanate is an isomer mixture consisting of 80% 2,4-toluene diisocyanate and 20% 2,6-toluene diisocyanate.

3. The multidimensional plant growth matrix material according to claim 1, characterized in that: The diatomaceous earth is purified diatomaceous earth, and the purification is carried out by roasting method, and the roasting temperature is 600-700°C.

4. The multidimensional plant growth matrix material according to claim 1, characterized in that: In the step (1), the ratio of the diatomaceous earth to the H2SO4 solution is 0.02-0.05 g / mL.

5. The multidimensional plant growth matrix material according to claim 1, characterized in that: In the step (2), the mass ratio of the silane coupling agent KH-602, ethanol and water is 1:(1-2):(3-5), and the mass ratio of the diatomaceous earth to the silane coupling agent KH-602 is 1:(0.2-0.4).

6. The multidimensional plant growth matrix material according to claim 1, characterized in that: In the step (3), the mass ratio of triethanolamine soap, castor oil, water and ethanol in the transparent solution is (1-3):1:(5-7):(2-4), and the ratio of the silane-modified diatomaceous earth to the transparent solution is 0.3-0.6 g / g.

7. The multidimensional plant growth matrix material according to claim 1, characterized in that: The amine catalyst is composed of bis(2-dimethylaminoethyl) ether and triethanolamine in a mass ratio of 3:

1.

8. The multidimensional plant growth matrix material according to claim 1, characterized in that: The foam stabilizer is an organosilicon surfactant; The cross-linking agent is diethanolamine or glycerol.

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