Facade greening using straw module fiber soil

Abstract

The application discloses a kind of facade greening uses straw module fiber soil, belong to landscaping technical field, including following weight part raw materials: fiber matrix 60-80 parts, urea-formaldehyde resin glue liquid 20-25 parts, amino bentonite 6-8 parts, the urea-formaldehyde resin glue liquid is prepared by following steps: with sodium hydroxide solution adjusting formaldehyde aqueous solution pH value is 8-9, temperature is raised to 40-45 DEG C, first stage urea is added, temperature is raised to 85-90 DEG C stirring reaction;With ammonium chloride solution adjusting pH value is 5-6, second stage urea and polyaldehyde sodium alginate are added, continue to react;With sodium hydroxide solution adjusting pH value is 7-8, third stage urea is added, stirring reaction;With sodium hydroxide solution adjusting pH value is 7-8 can be.Just with fiber matrix, urea-formaldehyde resin glue liquid and amino bentonite as raw material and be made of facade greening uses straw module fiber soil, has good water absorption, water retention effect.

Description

Technical Field

[0001] This invention belongs to the field of landscaping technology, specifically relating to a straw-modified fiber soil for facade greening. Background Technology

[0002] Vertical greening refers to the greening of buildings, which means making full use of different site conditions, selecting climbing plants and other plants to plant and attach to or cover various structures and other spatial structures. This includes greening of overpasses, building walls, slopes, river embankments, roofs, doorways, flower racks, pergolas, balconies, corridors, columns, fences, dead trees, and various artificial mountains and building facilities.

[0003] As a substrate material for vertical greening, it needs to withstand the natural environment of strong sunlight, high temperature and dryness, and as a substrate for plant growth, it needs to ensure the growth of plant roots. Traditional vertical greening substrate materials are mostly made of soil particles mixed with some plant fibers, with the addition of gravel and nutrient solution. Due to its loose structure, low durability and weak water retention capacity, its large-scale promotion and application in vertical greening is limited. Summary of the Invention

[0004] The purpose of this invention is to provide a straw module fiber soil for facade greening to solve the problems of low durability and water retention capacity of facade greening materials.

[0005] The objective of this invention can be achieved through the following technical solutions:

[0006] A type of straw module fiber soil for facade greening comprises the following raw materials in parts by weight: 60-80 parts fiber matrix, 20-25 parts urea-formaldehyde resin adhesive, and 6-8 parts aminated bentonite.

[0007] Further, the urea-formaldehyde resin solution is prepared by the following steps:

[0008] The pH of the formaldehyde aqueous solution was adjusted to 8-9 using sodium hydroxide solution, and the temperature was raised to 40-45℃. Urea (first-stage) was added, and the temperature was raised to 85-90℃ with stirring for 50 minutes. The pH was then adjusted to 5-6 using ammonium chloride solution, and urea (second-stage) and sodium alginate (polyaldehyde group) were added, with the reaction continuing for 20-30 minutes. The pH was adjusted to 7-8 using sodium hydroxide solution, and urea (third-stage) was added, with the reaction stirred for 20-30 minutes. The pH was then adjusted to 7-8 using sodium hydroxide solution to obtain urea-formaldehyde resin solution. Using a traditional urea-formaldehyde resin synthesis process, urea and sodium alginate (polyaldehyde group) were added in the second stage of synthesis to introduce aldehyde groups, reducing the amount of formaldehyde used and thus reducing the content of volatile formaldehyde at its source. Furthermore, the introduced aldehyde groups better bind with the raw materials during subsequent mixing.

[0009] Furthermore, the mass fraction of the aldehyde aqueous solution is 37%, the total molar ratio of urea and formaldehyde is 1:1.3; the molar ratio of urea in the first stage: urea in the second stage: urea in the third stage is 2:1:1.4; and the amount of polyaldehyde sodium alginate added is 3% of the mass of urea.

[0010] Furthermore, the polyaldehyde sodium alginate is prepared by the following steps:

[0011] Sodium alginate was added to anhydrous ethanol and stirred to obtain a dispersion. An aqueous solution of sodium periodate was then added, and the mixture was stirred at 20-30°C in the dark for 3-4 hours. After the reaction was complete, ethylene glycol was added to terminate the reaction, and ethanol was added to precipitate the precipitate. The precipitate was then filtered and dried under vacuum to obtain polyaldehyde sodium alginate. The mass fraction of sodium alginate in the dispersion was 15%, and the mass fraction of the aqueous solution of sodium periodate was 20%. The volume ratio of the dispersion to the aqueous solution of sodium periodate was 1:1 (the molar ratio of ethylene glycol to sodium periodate was 1:1).

[0012] Furthermore, the aminated bentonite is prepared by the following steps:

[0013] An equal volume of 3-aminopropyltriethoxysilane and a 90% (v / v) aqueous ethanol solution were mixed, and the pH was adjusted to 9 with hydrochloric acid. The mixture was stirred at 25°C for 20-30 min to obtain a silane coupling agent dispersion. Bentonite was then added and ultrasonically dispersed, and the mixture was stirred at 40°C for 2 h. After stirring, the mixture was filtered, washed with ethanol, dried, and ground through a 200-mesh sieve to obtain aminated bentonite. Introducing amino groups onto the surface of bentonite using a silane coupling agent not only improves the interfacial interaction between inorganic and organic matter but also provides more reaction sites. Combining aminated bentonite with polyaldehyde sodium alginate enhances the performance of straw-based modular fiber soil.

[0014] Furthermore, the fiber matrix comprises straw and coconut coir, wherein the mass ratio of straw to coconut coir is 3:1-2.

[0015] Furthermore, the straw is one or more of corn straw, rice straw, wheat straw, and sugarcane straw mixed in any proportion.

[0016] Furthermore, the straw undergoes alkaline treatment: the straw is dried (40°C) to constant weight, then soaked in a 2-3% sodium hydroxide aqueous solution for 2-4 hours, and then washed and dried (40°C). The purpose of alkaline treatment is to remove the wax on the surface of the straw, so that it can be better mixed with the raw materials and the bonding strength can be improved.

[0017] Furthermore, the length of the straw is 2-6 cm.

[0018] Furthermore, the facade greening uses straw module fiber soil prepared through the following steps:

[0019] Mix urea-formaldehyde resin and surfactant, add foam stabilizer and water and stir. Then add fiber matrix and modified bentonite, stir for 3-5 minutes, add curing agent, continue stirring for 1-2 minutes, and treat at 50-55℃ for 10-15 minutes to obtain a straw module fiber soil for facade greening.

[0020] Furthermore, the mass ratio of urea-formaldehyde resin adhesive, surfactant, foam stabilizer, water, and curing agent is 10:0.6:0.2:40:2.

[0021] Further, the curing agent is a mixture of phosphoric acid, ammonium dihydrogen phosphate, oxalic acid, and water in a mass ratio of 1.1:0.4:0.5:60; the surfactant is a mixture of sodium dodecylbenzenesulfonate and Tween-8O in a mass ratio of 1:3 or a mixture of sodium dodecylbenzenesulfonate and TSpan-80 in a mass ratio of 1:3; and the foam stabilizer is phenol.

[0022] The beneficial effects of this invention are:

[0023] A large amount of cultivation soil is needed in the process of vertical greening. This invention prepares a straw module fiber soil for vertical greening made of fiber matrix, urea-formaldehyde resin and aminated bentonite as raw materials, which has good water absorption and water retention effects.

[0024] The straw-based fiber soil of this invention can form a multi-layered water retention effect. The fiber matrix, urea-formaldehyde resin, and aminated bentonite in the raw materials can form a layered water absorption and release space system. The fiber matrix and aminated bentonite have different sizes. The bentonite has the function of absorbing water and expanding. The fiber matrix, as a substrate, provides loose physical support for the straw-based fiber soil. After being mixed with the raw materials, the urea-formaldehyde resin undergoes foaming treatment to form a porous foam material. It can also form a dynamic cross-linked structure of -C=N with the raw materials (derived from polyaldehyde sodium alginate and aminated bentonite, which have a dynamic reversible equilibrium in the aqueous phase). After breaking during the water absorption and expansion process, it has a good self-repair effect and can meet higher water absorption and retention requirements.

[0025] The urea-formaldehyde resin adhesive used in this invention has better adhesion and durability than untreated urea-formaldehyde resin, meeting the requirements for use in straw-modified fiber soil in natural environments with strong sunlight, high temperature, and dryness. Combined with the loose structure of the fiber matrix, it provides a lightweight, low-density planting system that adheres to the facade as a planting layer. It requires no external equipment or machinery, has no special requirements for the roof structure, and is widely applicable. After water is stored, it slowly releases moisture to support seed germination and plant growth, preventing root rot and other problems. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] Example 1

[0028] This embodiment provides an aminated bentonite, prepared through the following steps:

[0029] Equal volumes of 3-aminopropyltriethoxysilane and 90% ethanol aqueous solution were mixed, and hydrochloric acid was added to adjust the pH to 9. The mixture was stirred at 25°C for 20 min to obtain a silane coupling agent dispersion. Bentonite was added and ultrasonically dispersed. The mixture was stirred at 40°C for 2 h. After stirring, the mixture was filtered, washed with ethanol, dried, and ground through a 200-mesh sieve to obtain aminated bentonite.

[0030] Example 2

[0031] This embodiment provides a urea-formaldehyde resin adhesive, which is prepared through the following steps:

[0032] Sodium alginate was added to anhydrous ethanol and stirred to obtain a dispersion. An aqueous solution of sodium periodate was then added, and the mixture was stirred at 20°C in the dark for 3 hours. After the reaction was complete, ethylene glycol (the molar ratio of ethylene glycol to sodium periodate was 1:1) was added to terminate the reaction. Ethanol was then added to precipitate the precipitate, which was then filtered and dried under vacuum to obtain polyaldehyde sodium alginate. The dispersion contained 15% sodium alginate by mass, and the aqueous solution of sodium periodate contained 20% sodium periodate by mass, with a volume ratio of 1:1.

[0033] The pH of the formaldehyde aqueous solution was adjusted to 8 using sodium hydroxide solution, and the temperature was raised to 40°C. Urea (first stage) was added, and the mixture was heated to 85°C and stirred for 50 minutes. The pH was then adjusted to 5 using ammonium chloride solution, and urea (second stage) and sodium alginate (polyaldehyde) were added. The reaction was continued for 20 minutes. The pH was then adjusted to 7 using sodium hydroxide solution, and urea (third stage) was added. The reaction was stirred for 20 minutes. Finally, the pH was adjusted to 7 using sodium hydroxide solution to obtain urea-formaldehyde resin. The mass fraction of the formaldehyde aqueous solution was 37%, and the total molar ratio of urea to formaldehyde was 1:1.3. The molar ratio of urea (first stage):urea (second stage):urea (third stage) was 2:1:1.4. The amount of sodium alginate (polyaldehyde) added was 3% of the mass of urea.

[0034] Example 3

[0035] This embodiment provides a urea-formaldehyde resin adhesive, which is prepared through the following steps:

[0036] Sodium alginate was added to anhydrous ethanol and stirred to obtain a dispersion. An aqueous solution of sodium periodate was then added, and the mixture was stirred at 30°C in the dark for 4 hours. After the reaction was complete, ethylene glycol (the molar ratio of ethylene glycol to sodium periodate was 1:1) was added to terminate the reaction. Ethanol was then added to precipitate the precipitate, which was then filtered and dried under vacuum to obtain polyaldehyde sodium alginate. The dispersion contained 15% sodium alginate by mass, and the aqueous solution of sodium periodate contained 20% sodium periodate by mass, with a volume ratio of 1:1.

[0037] The pH of the formaldehyde aqueous solution was adjusted to 9 using sodium hydroxide solution, and the temperature was raised to 45°C. Urea (stage 1) was added, and the mixture was heated to 90°C and stirred for 50 minutes. The pH was then adjusted to 6 using ammonium chloride solution, and urea (stage 2) and sodium alginate (polyaldehyde) were added. The reaction was continued for 30 minutes. The pH was then adjusted to 8 using sodium hydroxide solution, and urea (stage 3) was added. The reaction was stirred for 30 minutes. Finally, the pH was adjusted to 8 using sodium hydroxide solution to obtain urea-formaldehyde resin. The mass fraction of the formaldehyde aqueous solution was 37%, and the total molar ratio of urea to formaldehyde was 1:1.3. The molar ratio of urea (stage 1):urea (stage 2):urea (stage 3) was 2:1:1.4. The amount of sodium alginate (polyaldehyde) added was 3% of the mass of urea.

[0038] Comparative Example 1

[0039] Compared with Example 3, this comparative example does not contain sodium polyaldehyde ester, but the other raw materials and preparation process are the same as in Example 3.

[0040] The free formaldehyde in the adhesives prepared in Examples 2-3 and Comparative Example 1 was tested according to standard GB / T14074-2017. The principle is as follows: ammonium chloride solution and a certain amount of sodium hydroxide are added to the sample, so that the generated ammonium hydroxide reacts with the formaldehyde in the resin adhesive to generate hexamethylenetetramine, and then the remaining ammonium hydroxide is titrated with hydrochloric acid.

[0041] Water resistance test of the adhesive: Take a wooden board (5cm long, 1cm wide, and 1mm thick), fix the wooden board with adhesive (with added hardener), add the prepared sample to boiling water, and record the time when the adhesive layer of the wooden board cracks.

[0042] The test results are recorded as shown in Table 1 below:

[0043] Table 1

[0044] project Example 2 Example 3 Comparative Example 1 Free formaldehyde content / % 0.212 0.205 0.384 Water resistance / min 60min 61min 27min

[0045] In the raw material formulation, increasing the amount of formaldehyde will lead to an increase in formaldehyde content, which in turn will lead to an increase in free formaldehyde content. This invention fundamentally reduces the formaldehyde content. Reducing the amount of formaldehyde will lead to a decrease in the hydroxymethyl content, which will reduce the bonding strength of the adhesive. This invention introduces sodium polyaldehyde alginate to reduce the amount of formaldehyde while maintaining the performance of the adhesive.

[0046] Example 4

[0047] This embodiment provides a straw module fiber soil for facade greening, comprising the following raw materials by weight: 60 parts fiber matrix, 20 parts urea-formaldehyde resin solution prepared according to the method in Example 2, and 6 parts aminated bentonite prepared according to the method in Example 1. It is prepared through the following steps:

[0048] The raw materials were weighed according to the specified weight proportions. Urea-formaldehyde resin and surfactant were mixed, followed by the addition of foam stabilizer and water. After stirring, fiber matrix and modified bentonite were added, and the mixture was stirred for 3 minutes. Then, curing agent was added, and stirring continued for 1 minute. The mixture was treated at 50℃ for 10 minutes to obtain a straw-modified fiber soil for vertical greening. The mass ratio of urea-formaldehyde resin, surfactant, foam stabilizer, water, and curing agent was 10:0.6:0.2:40:2. The curing agent is a mixture of phosphoric acid, ammonium dihydrogen phosphate, oxalic acid, and water in a mass ratio of 1.1:0.4:0.5:60. The surfactant is a mixture of sodium dodecylbenzenesulfonate and Tween-8O in a mass ratio of 1:3. The foam stabilizer is phenol. The fiber matrix includes straw and coconut coir, with a mass ratio of straw to coconut coir of 3:1. The straw is treated with alkaline solution: the straw is dried at 40°C to constant weight, then soaked in a 2% sodium hydroxide aqueous solution for 2 hours, washed with water, and dried at 40°C. The straw selected is corn straw with a length of 2-6 cm.

[0049] Example 5

[0050] This embodiment provides a straw module fiber soil for facade greening, comprising the following raw materials by weight: 80 parts fiber matrix, 25 parts urea-formaldehyde resin solution prepared according to the method in Example 3, and 8 parts aminated bentonite prepared according to the method in Example 1. It is prepared through the following steps:

[0051] The raw materials were weighed according to the specified weight proportions. Urea-formaldehyde resin and surfactant were mixed, followed by the addition of foam stabilizer and water. After stirring, fiber matrix and modified bentonite were added and stirred for 3 minutes. Then, curing agent was added and stirring continued for 1 minute. The mixture was treated at 50℃ for 10 minutes to obtain a straw-modified fiber soil for vertical greening. The mass ratio of urea-formaldehyde resin, surfactant, foam stabilizer, water, and curing agent was 10:0.6:0.2:40:2. The curing agent is a mixture of phosphoric acid, ammonium dihydrogen phosphate, oxalic acid, and water in a mass ratio of 1.1:0.4:0.5:60. The surfactant is a mixture of TSpan-80 in a mass ratio of 1:3. The foam stabilizer is phenol. The fiber matrix includes straw and coconut coir, with a mass ratio of straw to coconut coir of 3:2. The straw is treated with an alkaline solution: the straw is dried at 40°C to constant weight, then soaked in a 3% sodium hydroxide aqueous solution for 4 hours, washed with water, and dried at 40°C. The straw selected is corn straw with a length of 2-6 cm.

[0052] Example 6

[0053] This embodiment provides a straw module fiber soil for facade greening, comprising the following raw materials by weight: 80 parts fiber matrix, 25 parts urea-formaldehyde resin solution prepared according to the method in Example 3, and aminated bentonite prepared according to the method in Example 1. It is prepared through the following steps:

[0054] The raw materials were weighed according to the specified weight proportions. Urea-formaldehyde resin and surfactant were mixed, followed by the addition of foam stabilizer and water. After stirring, fiber matrix and modified bentonite were added, and the mixture was stirred for 5 minutes. Then, curing agent was added, and stirring continued for 2 minutes. The mixture was treated at 55℃ for 15 minutes to obtain a straw-modified fiber soil for vertical greening. The mass ratio of urea-formaldehyde resin, surfactant, foam stabilizer, water, and curing agent was 10:0.6:0.2:40:2. The curing agent is a mixture of phosphoric acid, ammonium dihydrogen phosphate, oxalic acid, and water in a mass ratio of 1.1:0.4:0.5:60. The surfactant is a mixture of TSpan-80 in a mass ratio of 1:3. The foam stabilizer is phenol. The fiber matrix includes straw and coconut coir, with a mass ratio of straw to coconut coir of 3:2. The straw is treated with an alkaline solution: the straw is dried at 40°C to constant weight, then soaked in a 3% sodium hydroxide aqueous solution for 4 hours, washed with water, and dried at 40°C. The straw selected is corn straw with a length of 2-6 cm.

[0055] Comparative Example 2

[0056] Compared with Example 6, this comparative example uses urea-formaldehyde resin solution instead of the sample prepared according to Comparative Example 1, while keeping the other raw materials and preparation process the same as in Example 6.

[0057] Comparative Example 3

[0058] Compared with Example 6, this comparative example replaces aminated bentonite with untreated bentonite, while the other raw materials and preparation process remain the same as in Example 6.

[0059] The water retention performance of samples prepared in Examples 4-6 and Comparative Examples 2-3 was tested: the water absorption ratio and water retention time of the samples were recorded; where, the water absorption ratio = the mass of the substrate after full water absorption / the mass of the substrate before full water absorption × 100%. The water retention time was tested as follows: water retention time = the time required for the fully water-absorbed substrate in the soil box to be placed in a 40℃ oven and dried with ventilation until the relative water holding capacity of the substrate is 0; the results are shown in Table 2.

[0060] Table 2

[0061] project Example 4 Example 5 Example 6 Comparative Example 2 Comparative Example 3 Absorption rate / % 3684 3699 3689 3257 3445 Water retention time / h 85 86 86 71 62

[0062] The water retention test results show that the straw module fiber soil for facade greening prepared by this invention has good water retention, which can extend the irrigation cycle of greening plants and reduce the amount of construction work.

[0063] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0064] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A type of facade greening using straw module fiber soil, characterized in that, The raw materials include the following parts by weight: 60-80 parts fiber matrix, 20-25 parts urea-formaldehyde resin solution, and 6-8 parts aminated bentonite, forming a dynamic cross-linked structure of -C=N between the raw materials; the urea-formaldehyde resin solution is prepared through the following steps: Adjust the pH of the formaldehyde aqueous solution to 8-9 with sodium hydroxide solution, heat to 40-45℃, add the first-stage urea, heat to 85-90℃ and stir for 50 minutes; adjust the pH to 5-6 with ammonium chloride solution, add the second-stage urea and polyaldehyde sodium alginate, and continue the reaction for 20-30 minutes; adjust the pH to 7-8 with sodium hydroxide solution, add the third-stage urea, and stir for 20-30 minutes; adjust the pH to 7-8 with sodium hydroxide solution to obtain urea-formaldehyde resin solution. The formaldehyde aqueous solution has a mass fraction of 37%, and the total molar ratio of urea to formaldehyde is 1:1.3; the molar ratio of urea in the first stage: urea in the second stage: urea in the third stage is 2:1:1.4; the amount of sodium polyaldehyde alginate added is 3% of the mass of urea.

2. The method of using straw module fiber soil for facade greening according to claim 1, characterized in that, The polyaldehyde sodium alginate is prepared by the following steps: Sodium alginate was added to anhydrous ethanol and stirred to obtain a dispersion. Sodium periodate aqueous solution was added and the mixture was stirred at room temperature in the dark for 3-4 hours. After the reaction was completed, ethylene glycol was added to terminate the reaction. Ethanol was added to precipitate the precipitate. After filtration and vacuum drying, polyaldehyde sodium alginate was obtained.

3. The method of using straw module fiber soil for facade greening according to claim 1, characterized in that, The aminated bentonite is prepared by the following steps: Equal volumes of 3-aminopropyltriethoxysilane and 90% ethanol aqueous solution were mixed, the pH was adjusted to 9, and the mixture was stirred at 25°C for 20-30 min to obtain a silane coupling agent dispersion. Bentonite was added and ultrasonically dispersed, and the mixture was stirred at 40°C for 2 h. After stirring, the mixture was filtered, washed with ethanol, dried, ground, and sieved to obtain aminated bentonite.

4. The straw module fiber soil for facade greening according to claim 1, characterized in that, The fiber matrix comprises straw and coconut coir, and the mass ratio of straw to coconut coir is 3:1-2.

5. The straw module fiber soil for facade greening according to claim 4, characterized in that, The straw is one or more of corn straw, rice straw, wheat straw, and sugarcane straw mixed in any proportion.

6. The straw module fiber soil for facade greening according to claim 4, characterized in that, The straw is treated with alkaline solution: the straw is dried to constant weight, then soaked in a 2-3% sodium hydroxide aqueous solution for 2-4 hours, and then washed and dried.

7. A method for using straw-modulated fiber soil for facade greening according to claim 4, characterized in that, The length of the straw is 2-6cm.

8. The straw module fiber soil for facade greening according to claim 1, characterized in that, The facade greening uses straw module fiber soil, which is prepared through the following steps: Mix urea-formaldehyde resin and surfactant, add foam stabilizer and water and stir. Then add fiber matrix and aminated bentonite and stir for 3-5 minutes. Add curing agent and continue stirring for 1-2 minutes. Treat at 50-55℃ for 10-15 minutes to obtain a straw module fiber soil for facade greening.

9. A method for using straw-modulated fiber soil for facade greening according to claim 8, characterized in that, The mass ratio of urea-formaldehyde resin adhesive, surfactant, foam stabilizer, water, and curing agent is 10:0.6:0.2:40:2; the curing agent is a mixture of phosphoric acid, ammonium dihydrogen phosphate, oxalic acid, and water in a mass ratio of 1.1:0.4:0.5:60; the surfactant is a mixture of sodium dodecylbenzenesulfonate and Tween-80 in a mass ratio of 1:3; and the foam stabilizer is phenol.