Polyurethane modified culture medium as well as preparation method and application thereof
By adding specific proportions of MDI and TDI type polyurethane prepolymers and high EO content polyether polyols to the seedling substrate, the problem of insufficient water retention capacity of the seedling substrate was solved, and efficient water retention and increased porosity of the substrate were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-31
- Publication Date
- 2026-04-03
AI Technical Summary
The existing seedling substrate has insufficient water retention capacity, making it difficult to meet the needs of large-scale planting.
MDI and TDI type polyurethane prepolymers were mixed with cultivation substrates, and the difference in NCO content between the two was controlled between -3 and 3. Polyurethane-modified cultivation substrates were prepared by combining polyether polyols with EO content ≥50%, thereby improving the water retention and porosity of the substrates.
It significantly improves the water retention capacity and porosity of polyurethane modified cultivation substrate, has moderate hardness, shortens the curing time, and improves the substrate's shaping effect.
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Abstract
Description
Technical Field
[0001] This application relates to the field of agricultural planting technology, specifically to a polyurethane modified cultivation substrate, its preparation method, and its uses. Background Technology
[0002] Traditional soil cultivation is susceptible to soil-borne diseases and continuous cropping obstacles, and soil resources are becoming increasingly scarce, making it difficult to meet the needs of large-scale planting. Therefore, substrate materials that can replace or optimize traditional soil use have received considerable attention. Since the introduction of factory-style tray seedling production technology in the 1980s, factory-style seedling production has flourished under the dual drive of market forces and policy, and the seedling substrate is the most important link in this technological route. Currently used seedling substrates are represented by coconut coir, vermiculite, and perlite, which, when mixed in a certain proportion, can achieve excellent water retention, moisture retention, and a loose, porous structure. These types of seedling substrates are not prone to compaction, and plant roots have ample space for respiration and growth, but there is still considerable room for improvement in their water retention capacity. Summary of the Invention
[0003] This application provides a polyurethane-modified cultivation substrate, its preparation method, and its uses, in order to solve the problem of insufficient water retention capacity in existing seedling substrates.
[0004] Therefore, this application provides a polyurethane-modified cultivation substrate, the raw materials of which include the following components: 100 volumes of cultivation substrate with an average particle size of 0.05-10 mm; 0.5-10 parts by weight of MDI-type polyurethane prepolymer; 1-10 parts by weight of TDI type polyurethane prepolymer; 75-100 parts by weight of water; where the unit of weight is g and the unit of volume is mL. The NCO content of MDI-type polyurethane prepolymer is denoted as a%, and the NCO content of TDI-type polyurethane prepolymer is denoted as b%. a and b satisfy: -3≤ab≤3.
[0005] The NCO content of MDI-type polyurethane prepolymer is the mass content of isocyanate in the MDI-type polyurethane prepolymer, and the NCO content of TDI-type polyurethane prepolymer is the mass content of isocyanate in the TDI-type polyurethane prepolymer.
[0006] In this application, the NCO content in both MDI-type and TDI-type polyurethane prepolymers was determined according to the following standard: GB / T12009.4-2016. The specific method is as follows: (1) Add 25 ml of di-n-butylamine solution (prepared by dissolving 129 g of di-n-butylamine in 1 L of toluene) to the iodine flask using a pipette, and rinse the flask wall with 10 ml of toluene. (2) Weigh the sample to an accuracy of 0.1 mg. Add the sample to an iodine flask containing di-n-butylamine. Shake gently to dissolve the sample completely. Let it stand at room temperature for 15 min. The reaction will cause the solution to heat up. The sample used for analysis should be completely liquefied. If it contains crystalline isocyanate, heat the sample carefully until it becomes a homogeneous liquid. (3) After the sample solution has cooled to room temperature, add 150 ml of acetone using a graduated cylinder and rinse the bottle wall and stopper; (4) Titrate excess di-n-butylamine by colorimetric titration; Colorimetric titration: Place the iodine flask on a magnetic stirrer and add 0.8 ml of bromophenol blue indicator solution (0.04% bromophenol blue sodium salt aqueous solution) with a pipette. Titrate with standard hydrochloric acid titration solution (concentration of 1 mol / L) until the color changes from blue to yellow and is maintained for 15 s. This is the titration endpoint.
[0007] (5) Perform blank tests at the same time. Each group of samples is titrated twice and the average value is taken.
[0008] In some implementations, 0.05 ≤ a ≤ 10; alternatively, 8.8 ≤ a ≤ 9.2.
[0009] In some implementations, 4 ≤ b ≤ 17; alternatively, 5.8 ≤ b ≤ 7.0.
[0010] In some embodiments, the cultivation substrate includes one or more of wood fiber, rice husk, peat, coconut coir, vermiculite, perlite, sawdust, sand, and red clay.
[0011] In some embodiments, the average particle size of the cultivation substrate is 0.05-10 mm.
[0012] In some embodiments, the raw materials for preparing the MDI-type polyurethane prepolymer include MDI-type isocyanate, a first polymeric polyol, a first chain extender, and a first polymerization inhibitor.
[0013] In some embodiments, the raw materials for preparing the TDI-type polyurethane prepolymer include TDI-type isocyanate, a second polymer polyol, a second chain extender, and a second polymerization inhibitor.
[0014] In some embodiments, the mass ratio of the MDI-type isocyanate, the first polymeric polyol, the first chain extender, and the first polymerization inhibitor in the raw materials for preparing the MDI-type polyurethane prepolymer is (50-80):(50-75):(0.1-5):(5-20).
[0015] In some embodiments, the mass ratio of the TDI-type isocyanate, the second polymer polyol, the second chain extender, and the second polymerization inhibitor in the raw materials for preparing the TDI-type polyurethane prepolymer is (24-30):(50-75):(0.1-5):(5-20).
[0016] In some embodiments, the MDI-type isocyanate is selected from one or more of 2,4-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate.
[0017] In some embodiments, the mass ratio of 4,4'-diphenylmethane diisocyanate to 2,4-diphenylmethane diisocyanate is ≥1:1.
[0018] In some embodiments, the TDI-type isocyanate is selected from one or more of toluene-2,4-diisocyanate and toluene-2,6-diisocyanate.
[0019] In some embodiments, the mass ratio of toluene-2,4-diisocyanate to toluene-2,6-diisocyanate is ≥1:1.
[0020] In some embodiments, the first polymeric polyol and the second polymeric polyol independently comprise polyether polyol and / or polyester polyol.
[0021] In some embodiments, the first chain extender and the second chain extender are independently selected from small molecule polyols. Optionally, the first chain extender and the second chain extender independently comprise C2-C8 diols and / or triols. More preferably, the first chain extender and the second chain extender independently comprise C2-C5 diols and / or triols. Even more preferably, the first chain extender and the second chain extender are independently selected from one or more of 1,2-propanediol, 1,3-butanediol, 1,2-pentanediol, and glycerol.
[0022] In some embodiments, the first polymerization inhibitor and the second polymerization inhibitor independently comprise phosphoric acid.
[0023] In some embodiments, the first polymer polyol and the second polymer polyol are independently selected from polyether polyols with an EO content of ≥50%, and polyether polyols with an EO content of ≥70% are optional.
[0024] EO is an ethylene oxide group with the structural formula -(O-CH2CH2)-.
[0025] The term "EO content" refers to the percentage of the mass of EO in a polyether polyol relative to the total mass of the polyether polyol.
[0026] In some embodiments, the raw materials of the polyurethane modified cultivation substrate also include 0.05-3 parts by weight of additives.
[0027] Optionally, the additive is selected from one or more of surfactants, pH adjusters, organic solvents, or rheology modifiers. Surfactants, by altering the interfacial tension of the water-substrate mixture, regulate the pore size of the polyurethane-modified cultivation substrate and assist in the uniform dispersion of large-particle cultivation substrate in water. Rheology modifiers alter the rheological properties of the water-substrate mixture, making it homogeneous and stable, allowing for prefabrication and long-term storage, and facilitating transportation in pipelines, thus helping to improve pipeline blockage issues during the production process.
[0028] Optionally, the surfactant includes one or more of nonionic surfactants, anionic surfactants, and amphoteric surfactants, with nonionic surfactants being a preferred choice; further optionally, the nonionic surfactant is selected from one or more of polyether polyols, polyoxyethylene ethers, and polyoxyethylene esters, and more preferably polyether polyols.
[0029] Optionally, the organic solvent is selected from one or more of 1,2-propanediol, 1,3-butanediol, and 1,2-pentanediol.
[0030] Optionally, the rheology modifier includes one or more of cellulose, xanthan gum, polyacrylic acid, and sodium polyacrylate.
[0031] In some embodiments, the additive comprises a composition of polyether polyol, sodium polyacrylate and cellulose, wherein the mass ratio of polyether polyol, sodium polyacrylate and cellulose is 1:(1-2):(1-2).
[0032] On the other hand, this application also provides a method for preparing any of the polyurethane-modified cultivation substrates described above, comprising the following steps: Step S1 involves mixing the cultivation substrate with water to obtain a water-based substrate; Step S2: Mix water, MDI-type polyurethane prepolymer and TDI-type polyurethane prepolymer, react and mature to obtain polyurethane modified cultivation substrate; optionally, in step S2, the mixing is carried out by homogenization; optionally, step S1 also includes the mixing of additives.
[0033] On the other hand, it also provides the application of any of the polyurethane modified cultivation substrates described above or the polyurethane modified cultivation substrates prepared by the methods described above in soilless cultivation.
[0034] The water hardness specified in the formula is ≤450 mg / L CaCO3. The types of water include, but are not limited to, deionized water, well water, tap water, river water, and lake water. A suitable water source can be selected according to production needs, but the water hardness should not exceed the range specified in this application. Otherwise, the performance of the polyurethane modified cultivation substrate will decrease, and the production process may be hindered.
[0035] 1. The polyurethane-modified cultivation substrate provided in this application comprises the following components: 100 parts by volume of cultivation substrate with an average particle size of 0.05-10 mm; 0.5-10 parts by weight of MDI-type polyurethane prepolymer; 1-10 parts by weight of TDI-type polyurethane prepolymer; and 75-100 parts by weight of water. Wherein, when the unit of weight is g, the unit of volume is mL. The NCO content of the MDI-type polyurethane prepolymer is denoted as a%, and the NCO content of the TDI-type polyurethane prepolymer is denoted as b%. a and b satisfy: -3 ≤ ab ≤ 3. Firstly, the MDI-type polyurethane prepolymer is used to improve the softness of the cultivation substrate, while the TDI-type polyurethane prepolymer is used to improve the rigidity of the cultivation substrate. A cultivation substrate that is too rigid is easily damaged during transportation and demolding, and is also detrimental to plant root growth. A cultivation substrate that is too soft will increase the difficulty of demolding. By adding the two specific types of polyurethane prepolymers mentioned above to the cultivation substrate, the hard segments of the polyurethane molecules, MDI and TDI, are arranged alternately, resulting in a polyurethane-modified cultivation substrate with both rigidity and flexibility, and excellent water retention and moisture retention capabilities. However, when the difference in NCO content between the two polyurethane prepolymers is greater than 3 or less than -3, the compatibility between the two prepolymers decreases, leading to poorer or harder shaping of the resulting polyurethane-modified cultivation substrate product, and a reduction in water retention capacity. For cultivation substrates with an average particle size <0.05mm or >10mm, the polyurethane-modified cultivation substrate made with polyurethane prepolymers exhibits poor shaping or is difficult to shape, and has small pores and poor water retention and moisture retention performance. Therefore, by adding the two specific types of polyurethane prepolymers to the cultivation substrate within the above-mentioned average particle size range and controlling the difference in NCO content between the two to between -3 and 3, the shaping effect, porosity, and water retention and moisture retention capabilities of the polyurethane-modified cultivation substrate are significantly improved, while maintaining a suitable level of hardness and softness.
[0036] 2. The polyurethane modified cultivation substrate provided in this application, by limiting 0.05≤a≤10; especially 8.8≤a≤9.2, makes the MDI type prepolymer more reactive, ensuring good molding of the modified substrate while further shortening the curing time.
[0037] 3. The polyurethane modified cultivation substrate provided in this application, by limiting 4≤b≤17; especially 5.8≤b≤7.0, makes the TDI type prepolymer more reactive, ensuring good molding of the modified substrate while further shortening the curing time.
[0038] 4. The polyurethane modified cultivation substrate provided in this application, in the raw materials for preparing MDI-type polyurethane prepolymer or TDI-type polyurethane prepolymer, uses polyether polyols with an EO content ≥50%, especially polyether polyols with an EO content ≥70%, which makes the soft segments of the prepolymer molecules more hydrophilic, accelerates the reaction rate, and shortens the preparation time of the polyurethane modified cultivation substrate.
[0039] 5. The polyurethane modified cultivation substrate provided in this application uses a composition including polyether polyol, sodium polyacrylate and cellulose as an auxiliary agent when preparing the water-based substrate, and controls the mass ratio of polyether polyol, sodium polyacrylate and cellulose to be 1:(1-2):(1-2). By changing the surface tension, the cultivation substrate and water are quickly and evenly mixed. Through the interaction of hydrogen bonds with water and the cross-linking of macromolecular groups with the cultivation substrate, the water-based substrate remains uniform and stable for a long time. Detailed Implementation
[0040] The following embodiments are provided to better understand this application. However, the following embodiments do not constitute a limitation on the content and scope of protection of this application. Any product that is the same as or similar to this application, derived by anyone under the guidance of this application or by combining the features of this application with other prior art, falls within the scope of protection of this application.
[0041] Unless otherwise specified, all experimental steps or conditions in the examples were performed according to conventional experimental procedures and conditions in the art. Reagents or instruments whose manufacturers are not specified are all commercially available products.
[0042] The peat was purchased from Tianyuansu Ecological Agriculture (Jinan) Co., Ltd., model: TYS-Imported Peat, with an average particle size of 0.05mm. Coconut coir A, purchased from Anhui Chunfen Agricultural Technology Co., Ltd., has an average particle size of 2mm; Coconut coir B, purchased from Anhui Chunfen Agricultural Technology Co., Ltd., has an average particle size of 9mm. Coconut coir C, purchased from Anhui Chunfen Agricultural Technology Co., Ltd., has an average particle size of 7.5 mm; Sawdust A, purchased from Fangcheng County Sanli Thermal Energy Development Co., Ltd., has an average particle size of 2.5mm; Sawdust B, purchased from Fangcheng County Sanli Thermal Energy Development Co., Ltd., has an average particle size of 4.5mm; Polyether polyol A: EO content is 70%, WANOL® PEG1000B, provided by Wanhua Chemical Group Co., Ltd., with an average molecular weight of 3000; Polyether polyol B: EO content is 60%, purchased from Guangdong Jieshi Chemical Co., Ltd., CF-60, average molecular weight is 3000; Hydroxypropyl methylcellulose, purchased from Aladdin, USP2910 grade; Sodium polyacrylate, supplied by Wanhua Chemical Group Co., Ltd., grade: WHS 700; Xanthan gum, purchased from Aladdin, USP grade.
[0043] Example 1 This embodiment provides a polyurethane-modified cultivation substrate, the formulation of which is shown in Table 1 below: Table 1. Raw materials and dosage of each raw material in polyurethane modified cultivation substrate
[0044] Its preparation method is as follows: 1) Take the cultivation substrate, add deionized water and stir evenly to obtain water-based substrate.
[0045] 2) Add MDI type polyurethane prepolymer and TDI type polyurethane prepolymer to the water material respectively, homogenize with a homogenizer at a speed of 4500 rpm for 14 seconds, pour into a mold and let stand for 15 minutes.
[0046] 3) Demolding to obtain polyurethane modified cultivation substrate.
[0047] The raw materials for the MDI-type polyurethane prepolymer include 60 kg of diisocyanate (4,4'-diphenylmethane diisocyanate: 2,4-diphenylmethane diisocyanate in a mass ratio of 1:1), 55 kg of polyether polyol A (70% EO content, WANOL® PEG1000B, Wanhua Chemical), 1.4 kg of propylene glycol, and 10 g of phosphoric acid.
[0048] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain MDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0049] The raw materials for the TDI type polyurethane prepolymer include 24.6 kg of diisocyanate (toluene-2,4-diisocyanate:toluene-2,6-diisocyanate in a mass ratio of 1:1), 75 kg of polyether polyol A (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 5 kg of propylene glycol, and 10 g of phosphoric acid.
[0050] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain TDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0051] Example 2 This embodiment provides a polyurethane-modified cultivation substrate, the formulation of which is shown in Table 2 below: Table 2. Raw materials and dosage of each raw material in polyurethane modified cultivation substrate.
[0052] The preparation method is the same as in Example 1.
[0053] The raw materials for the MDI-type polyurethane prepolymer include 72 kg of diisocyanate (4,4'-diphenylmethane diisocyanate: 2,4-diphenylmethane diisocyanate in a mass ratio of 5:1), 50 kg of polyether polyol A (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 0.2 kg of propylene glycol, and 10 g of phosphoric acid.
[0054] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain MDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0055] The raw materials for the TDI type polyurethane prepolymer include 24 kg of diisocyanate (toluene-2,4-diisocyanate:toluene-2,6-diisocyanate in a mass ratio of 5:1), 60 kg of polyether polyol A (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 1.9 kg of propylene glycol, and 10 g of phosphoric acid.
[0056] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain TDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0057] Example 3 This embodiment provides a polyurethane-modified cultivation substrate, the formulation of which is shown in Table 3 below: Table 3. Raw materials and dosage of each raw material in polyurethane modified cultivation substrate
[0058] The preparation method is the same as in Example 1. The raw materials for the MDI-type polyurethane prepolymer include 63 kg of diisocyanate (4,4'-diphenylmethane diisocyanate: 2,4-diphenylmethane diisocyanate in a mass ratio of 20:1), 75 kg of polyether polyol A (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 5 kg of propylene glycol, and 10 g of phosphoric acid.
[0059] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain MDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0060] The raw materials for the TDI type polyurethane prepolymer include 24.15 kg of diisocyanate (toluene-2,4-diisocyanate:toluene-2,6-diisocyanate in a mass ratio of 20:1), 72.5 kg of polyether polyol A (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 5 kg of propylene glycol, and 10 g of phosphoric acid.
[0061] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain TDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0062] Example 4 This embodiment provides a polyurethane-modified cultivation substrate, the formulation of which is shown in Table 4 below: Table 4. Raw materials and dosage of each raw material in polyurethane modified cultivation substrate
[0063] The preparation method is the same as in Example 1. The raw materials for the MDI-type polyurethane prepolymer include 63 kg of diisocyanate (4,4'-diphenylmethane diisocyanate: 2,4-diphenylmethane diisocyanate by mass ratio of 20:1), 55 kg of polyether polyol A (70% EO content, WANOL® PEG1000B, Wanhua Chemical), 2.7 kg of propylene glycol, and 10 g of phosphoric acid.
[0064] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain MDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0065] The raw materials for the TDI type polyurethane prepolymer include 25.2 kg of diisocyanate (toluene-2,4-diisocyanate:toluene-2,6-diisocyanate in a mass ratio of 20:1), 65 kg of polyether polyol A (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 2.6 kg of propylene glycol, and 10 g of phosphoric acid.
[0066] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain TDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0067] Example 5 This embodiment provides a polyurethane-modified cultivation substrate, the formulation of which is shown in Table 5 below: Table 5. Raw materials and dosage of each raw material in polyurethane modified cultivation substrate
[0068] The preparation method is the same as in Example 1. The raw materials for the MDI-type polyurethane prepolymer include 69.3 kg of diisocyanate (4,4'-diphenylmethane diisocyanate: 2,4-diphenylmethane diisocyanate by mass ratio of 20:1), 56 kg of polyether polyol A (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 1.1 kg of propylene glycol, and 10 g of phosphoric acid.
[0069] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain MDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0070] The raw materials for the TDI type polyurethane prepolymer include 25.2 kg of diisocyanate (toluene-2,4-diisocyanate:toluene-2,6-diisocyanate in a mass ratio of 20:1), 51.5 kg of polyether polyol A (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 2.5 kg of propylene glycol, and 10 g of phosphoric acid.
[0071] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain TDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0072] Example 6 This embodiment provides a polyurethane-modified cultivation substrate, the formulation of which is shown in Table 6 below: Table 6. Raw materials and dosage of each raw material in polyurethane modified cultivation substrate
[0073] The preparation method is the same as in Example 1. The raw materials for the MDI-type polyurethane prepolymer include 79.8 kg of diisocyanate (4,4'-diphenylmethane diisocyanate: 2,4-diphenylmethane diisocyanate by mass ratio of 20:1), 50 kg of polyether polyol A (70% EO content, WANOL® PEG1000B, Wanhua Chemical), 0.25 kg of propylene glycol, and 10 g of phosphoric acid.
[0074] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain MDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0075] The raw materials for the TDI type polyurethane prepolymer include 25.2 kg of diisocyanate (toluene-2,4-diisocyanate:toluene-2,6-diisocyanate in a mass ratio of 20:1), 50 kg of polyether polyol A (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 1.4 kg of propylene glycol, and 15 g of phosphoric acid.
[0076] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain TDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0077] Example 7 This embodiment provides a polyurethane-modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that the raw materials also include 1g of hydroxypropyl methylcellulose. In step 1), the hydroxypropyl methylcellulose is added to the cultivation substrate along with deionized water and mixed evenly.
[0078] Example 8 This embodiment provides a polyurethane-modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that the raw materials also include 1g of sodium polyacrylate. In step 1), the sodium polyacrylate is added to the cultivation substrate along with deionized water and mixed thoroughly.
[0079] Example 9 This embodiment provides a polyurethane-modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that the raw materials also include 1g of polyether polyol A. In step 1), polyether polyol A is added to the cultivation substrate together with deionized water and mixed evenly.
[0080] Example 10 This embodiment provides a polyurethane-modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that the raw materials also include 1g of 1,2-propanediol. In step 1), 1,2-propanediol is added to the cultivation substrate along with deionized water and mixed evenly.
[0081] Example 11 This embodiment provides a polyurethane-modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that the raw materials also include 1g of xanthan gum. In step 1), the xanthan gum is added to the cultivation substrate along with deionized water and mixed thoroughly.
[0082] Example 12 This embodiment provides a polyurethane-modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that the raw materials also include 1g of an auxiliary agent (specifically, sodium polyacrylate, polyether polyol A, and cellulose in a mass ratio of 1:1:2). The auxiliary agent is added to the cultivation substrate along with deionized water in step 1 and mixed thoroughly.
[0083] Example 13 This embodiment provides a polyurethane-modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that the raw materials also include 60g of an auxiliary agent, which is composed of sodium polyacrylate, polyether polyol A, and hydroxypropyl methylcellulose in a mass ratio of 1:2:1. In step 1), this auxiliary agent is added to the cultivation substrate along with deionized water and mixed evenly.
[0084] Example 14 This embodiment provides a polyurethane modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that polyether polyol B of the same mass is used instead of polyether polyol A in the preparation process of TDI type polyurethane prepolymer.
[0085] Example 15 This embodiment provides a polyurethane modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that polyether polyol B of the same mass is used instead of polyether polyol A in the preparation process of MDI type polyurethane prepolymer.
[0086] Example 16 This embodiment provides a polyurethane modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that the mass ratio of diisocyanate used in the preparation of TDI type polyurethane prepolymer is different. In this embodiment, toluene-2,4-diisocyanate:toluene-2,6-diisocyanate with a mass ratio of 1:5 is used as diisocyanate in the preparation of TDI type polyurethane prepolymer, and the total mass of diisocyanate remains unchanged.
[0087] Example 17 This embodiment provides a polyurethane modified cultivation substrate and its preparation method, which is basically the same as that in Example 1, except that the mass ratio of diisocyanate used in the preparation of MDI-type polyurethane prepolymer is different. In this embodiment, 4,4'-diphenylmethane diisocyanate:2,4-diphenylmethane diisocyanate with a mass ratio of 1:5 is used as diisocyanate in the preparation of MDI-type polyurethane prepolymer, and the total mass of diisocyanate remains unchanged.
[0088] Example 18 This embodiment provides a polyurethane-modified cultivation substrate and its preparation method, the formulation of which is shown in Table 7 below: Table 7. Raw materials and dosage of each raw material in polyurethane modified cultivation substrate
[0089] The preparation method is the same as in Example 1.
[0090] In this embodiment, the raw materials for the MDI-type polyurethane prepolymer include: 80 kg of diisocyanate (4,4'-diphenylmethane diisocyanate: 2,4-diphenylmethane diisocyanate in a mass ratio of 1:1), 50 kg of polyether polyol (70% EO content, WANOL® PEG1000B, Wanhua Chemical), 0.1 kg, and 10 g of phosphoric acid.
[0091] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain MDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0092] In this embodiment, the raw materials for the TDI-type polyurethane prepolymer include: 24 kg of diisocyanate (toluene-2,4-diisocyanate:toluene-2,6-diisocyanate in a mass ratio of 1:1), 71 kg of polyether polyol (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 2.5 kg of propylene glycol, and 10 g of phosphoric acid.
[0093] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain TDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0094] Example 19 This embodiment provides a polyurethane-modified cultivation substrate and its preparation method, the formulation of which is shown in Table 8 below: Table 8. Raw materials and dosage of each raw material in polyurethane modified cultivation substrate
[0095] The preparation method is the same as in Example 1.
[0096] In this embodiment, the raw materials for the MDI-type polyurethane prepolymer include: 80 kg of diisocyanate (4,4'-diphenylmethane diisocyanate: 2,4-diphenylmethane diisocyanate in a mass ratio of 1:1), 52 kg of polyether polyol (70% EO content, WANOL® PEG1000B, Wanhua Chemical), 0.3 kg, and 10 g of phosphoric acid.
[0097] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain MDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0098] The raw materials for the TDI-type polyurethane prepolymer in this embodiment include: 26 kg of diisocyanate (toluene-2,4-diisocyanate:toluene-2,6-diisocyanate in a mass ratio of 1:1), 70 kg of polyether polyol (EO content of 70%, WANOL® PEG1000B, Wanhua Chemical), 4.3 kg of propylene glycol, and 10 g of phosphoric acid.
[0099] The preparation method is as follows: the above raw materials are mixed at 75 °C for 5 h to obtain TDI type polyurethane prepolymer. The NCO content of the prepolymer is shown in Table 9.
[0100] Comparative Example 1 The only difference from Example 1 is that a cultivation substrate with the same mass and an average particle size of 0.04 mm (specifically, sand, collected from the Taklamakan Desert) was used instead of the cultivation substrate used in Example 1.
[0101] Comparative Example 2 The only difference from Example 1 is that a cultivation substrate with the same mass and an average particle size of 12 mm (specific type: perlite, manufacturer: Lingshou County Kaiqi Mineral Products Processing Plant, model: 98% perlite) was used instead of the cultivation substrate used in Example 1.
[0102] Comparative Example 3 The only difference from Example 1 is that the MDI-type polyurethane prepolymer is different. The MDI-type polyurethane prepolymer prepared in Example 2 is used instead of the MDI-type polyurethane prepolymer prepared in Example 1, resulting in ab being different, as shown in Table 9.
[0103] Comparative Example 4 The only difference from Example 1 is that the TDI-type polyurethane prepolymer is different. The TDI-type polyurethane prepolymer prepared in Example 5 is used instead of the TDI-type polyurethane prepolymer prepared in Example 1, resulting in ab being different, as shown in Table 9.
[0104] Comparative Example 5 The only difference from Example 1 is that no TDI-type polyurethane prepolymer was added.
[0105] Comparative Example 6 The only difference from Example 1 is that no MDI-type polyurethane prepolymer was added.
[0106] Table 9. Values of NCO content in prepolymers
[0107] Test Example 1 Polyurethane-modified cultivation substrates were prepared according to the methods of each embodiment and comparative example, wherein 72-cell trays were used as molds in the preparation process. After demolding, the state of the substrate was observed. If the substrate could stably maintain its shape in the mold, it was considered formed; if the substrate was loose and fragmented and could not maintain its shape in the mold, it was considered not formed.
[0108] Curing time: The time from the end of homogenization during the preparation process until the polyurethane modified cultivation substrate is completely cured is recorded.
[0109] Porosity test: The porosity of each group of polyurethane modified cultivation substrates was obtained by testing according to GB / T 10799-2008 standard.
[0110] Softness: Squeeze the polyurethane modified cultivation substrate by hand to feel its softness. The softness level is represented by 1, 2, 3, 4, and 5. The higher the number, the harder it is. 1 is very soft, 2 is relatively soft, 3 is moderately soft, 4 is relatively hard, and 5 is very hard.
[0111] Presence or absence of white crust: Observe the appearance of the matured polyurethane modified cultivation substrate and check for the presence of a white crust on the surface. If a white crust is present on the surface and it has a plastic feel, record it as "present". If no white crust appears on the surface and it presents the appearance of the cultivation substrate itself, record it as "absent".
[0112] Water absorption ratio: The polyurethane modified cultivation substrate was placed in a 50℃ oven for 24 hours and the initial mass m1 was recorded. Then, the polyurethane modified cultivation substrate was soaked in excess water for 2 hours and the mass m2 was recorded. The water absorption ratio n = (m2-m1) / m1.
[0113] Table 10 Test Results
[0114] The results show that, compared with comparative examples 1-6, the polyurethane modified cultivation substrate formulations provided in the embodiments of this application have a shaping effect, moderate porosity, water absorption, and softness / hardness, and no white crust on the surface.
[0115] Compared with Examples 7-13, Examples 7-13 of this application can significantly improve the stability of water-based materials by adding additives, thereby improving the water absorption of the matrix, especially Examples 12 and 13.
[0116] Compared with Examples 14-15, Example 1 of this application uses a prepolymer prepared by polyether polyol with EO content within the preferred range, which can further accelerate the maturation of the matrix, thereby shortening the maturation time and improving porosity and water absorption.
[0117] Compared with Examples 18-19, Examples 18-19 of this application can further improve the water absorption ratio and porosity of the matrix by limiting the NCO content of the MDI type polyurethane prepolymer or the NCO content of the TDI type polyurethane prepolymer within a preferred range.
[0118] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.
Claims
1. A polyurethane-modified cultivation substrate, characterized in that, Its raw materials include the following components: 100 volumes of cultivation substrate with an average particle size of 0.05-10 mm; 0.5-10 parts by weight of MDI-type polyurethane prepolymer; 1-10 parts by weight of TDI type polyurethane prepolymer; 75-100 parts by weight of water; where the unit of weight is g and the unit of volume is mL. The NCO content of MDI-type polyurethane prepolymer is denoted as a%, and the NCO content of TDI-type polyurethane prepolymer is denoted as b%. a and b satisfy: -3≤ab≤3.
2. The polyurethane-modified cultivation substrate according to claim 1, characterized in that, At least one of the following must be met: A. 0.05 ≤ a ≤ 10; Alternatively, 8.8 ≤ a ≤ 9.2; B, 4≤b≤17; optional, 5.8≤b≤7.0; C. The cultivation substrate includes one or more of the following: wood fiber, rice husk, peat, coconut coir, vermiculite, perlite, sawdust, sand, and red clay. D. The average particle size of the cultivation substrate is 0.05-10 mm.
3. The polyurethane-modified cultivation substrate according to claim 1 or 2, characterized in that, The raw materials for preparing the MDI-type polyurethane prepolymer include MDI-type isocyanate, a first polymer polyol, a first chain extender, and a first polymerization inhibitor; And / or, the raw materials for preparing the TDI-type polyurethane prepolymer include TDI-type isocyanate, a second polymer polyol, a second chain extender, and a second polymerization inhibitor.
4. The polyurethane-modified cultivation substrate according to claim 3, characterized in that, In the raw materials for preparing the MDI-type polyurethane prepolymer, the mass ratio of the MDI-type isocyanate, the first polymer polyol, the first chain extender, and the first polymerization inhibitor is (50-80):(50-75):(0.1-5):(5-20). And / or, in the raw materials for preparing the TDI type polyurethane prepolymer, the mass ratio of the TDI type isocyanate, the second polymer polyol, the second chain extender and the second polymerization inhibitor is (24-30):(50-75):(0.1-5):(5-20).
5. The polyurethane-modified cultivation substrate according to claim 3 or 4, characterized in that, The MDI type isocyanate is selected from one or more of 2,4-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate; And / or, the TDI type isocyanate is selected from one or more of toluene-2,4-diisocyanate and toluene-2,6-diisocyanate; And / or, the first polymer polyol and the second polymer polyol independently comprise polyether polyol and / or polyester polyol; And / or, the first chain extender and the second chain extender are independently selected from small molecule polyols; optionally, the first chain extender and the second chain extender independently comprise C2-C8 diols and / or triols; further optionally, the first chain extender and the second chain extender independently comprise C2-C5 diols and / or triols; more preferably, the first chain extender and the second chain extender are independently selected from one or more of 1,2-propanediol, 1,3-butanediol, 1,2-pentanediol, and glycerol. And / or, the first polymerization inhibitor and the second polymerization inhibitor independently include phosphoric acid.
6. The polyurethane-modified cultivation substrate according to claim 5, characterized in that, The first polymer polyol and the second polymer polyol are independently selected from polyether polyols with an EO content of ≥50%, and polyether polyols with an EO content of ≥70% are also optional.
7. The polyurethane-modified cultivation substrate according to any one of claims 1-6, characterized in that, The raw materials of the polyurethane modified cultivation substrate also include 0.05-3 parts by weight of additives; Optionally, the additive is selected from one or more of surfactants, pH adjusters, organic solvents, or rheology modifiers; Optionally, the surfactant includes one or more of nonionic surfactants, anionic surfactants, and amphoteric surfactants, with nonionic surfactants being a preferred choice; further optionally, the nonionic surfactant is selected from one or more of polyether polyols, polyoxyethylene ethers, and polyoxyethylene esters, and more preferably polyether polyols. Optionally, the organic solvent is selected from one or more of 1,2-propanediol, 1,3-butanediol, and 1,2-pentanediol; Optionally, the rheology modifier includes one or more of cellulose, xanthan gum, polyacrylic acid, and sodium polyacrylate.
8. The polyurethane-modified cultivation substrate according to claim 7, characterized in that, The additives include a composition of polyether polyol, sodium polyacrylate and cellulose, wherein the mass ratio of polyether polyol, sodium polyacrylate and cellulose is 1:(1-2):(1-2).
9. A method for preparing a polyurethane-modified cultivation substrate according to any one of claims 1-8, characterized in that, Includes the following steps: Step S1 involves mixing the cultivation substrate with water to obtain a water-based substrate; Step S2: Mix water, MDI-type polyurethane prepolymer and TDI-type polyurethane prepolymer, and mature to obtain polyurethane-modified cultivation substrate; optionally, in step S2, the mixing is carried out by homogenization; optionally, step S1 also includes the mixing of additives.
10. The application of a polyurethane modified cultivation substrate according to any one of claims 1-8 or a polyurethane modified cultivation substrate prepared by the preparation method according to claim 9 in soilless cultivation.