Preparation Method of Hydrophilic Porous Noise-Reducing Organic Surface Coverings

Abstract

The present invention discloses a preparation method of a hydrophilic porous noise-reducing organic ground cover, which is specifically implemented according to the following steps: Step 1, obtain branches and cut the branches to obtain cut pieces or cut grains; Step 2, naturally dry the cut pieces or cut grains obtained in Step 1 to form a common organic ground cover; Step 3, prepare an infiltration modifier solution, and then perform surface modification on the common organic ground cover formed in Step 2 by spraying or infiltration, and finally obtain a cut material substrate after pre-drying; Step 4, prepare a pore-forming agent; Step 5, enable the cut material substrate obtained in Step 3 to fully absorb the pore-forming agent prepared in Step 4, and then undergo track-type microwave drying to obtain a hydrophilic porous noise-reducing organic ground cover. The present invention utilizes tracheids to absorb the pore-forming agent to form gas-induced pores, forming a surface porous structure, which can effectively reduce noise.

Description

Technical Field

[0001] The present invention belongs to the technical field of surface coverings, and particularly relates to a preparation method of a hydrophilic porous noise-reducing organic surface covering. Background Art

[0002] The impact of noise is not limited to the aesthetic feeling of the environment. It also has a negative impact on the habitats of birds and animals, and is also an important factor leading to the incidence of human cardiovascular diseases, aging and myocardial infarction. Porous sound-absorbing materials are widely used in engineering facilities such as buildings and roads, such as sound-absorbing guardrails on highways and porous sound-absorbing walls in concert halls. The porous sound-absorbing mechanism is that there are a large number of tiny pores inside the material. Sound waves can penetrate deep into the material along these pores and interact with the material to achieve phenomena such as Helmholtz resonance and conversion of sound energy into heat energy to eliminate and absorb sound. Surface porosity is a prerequisite for forming a good sound-absorbing material. The sound absorption coefficient is the sum of the sound wave energy absorbed by the substance and the incident sound wave energy. The larger the sound absorption coefficient, the better the sound absorption effect of this material. Generally, materials with an average sound absorption coefficient greater than 0.2 are called sound-absorbing materials.

[0003] Organic coverings are made from organic waste such as urban garden pruning and agricultural crop straw as the main base materials. After removing leaves and impurities, they are processed through extrusion, cutting, drying, coloring and other processes to form different flower colors and patterns. They have the ability to regulate soil temperature, reduce soil salinity, effectively control weeds, absorb and decompose pollution, beautify and green the environment, reduce soil erosion and compaction, and reduce the green space maintenance cost. They can be laid on the bare ground surface of parks, green belts, urban gardens, landscape woodlands, GMP standard enterprise factory areas, and construction excavation sites to form a covering. The cuttings and particles of garden pruning branches can be used as surface coverings. However, the vessel elements and tracheids in the xylem of garden pruning are dead cells with thick walls and elongation, showing various patterns of annular, spiral, scalariform, reticulate and pitted on the walls. Among them, tracheids are single cells with sharp ends, no perforations in the end walls, smooth and less porous surfaces, and do not have the ability to reduce noise. Summary of the Invention

[0004] The purpose of the present invention is to provide a preparation method of a hydrophilic porous noise-reducing organic surface covering, and solve the problems that existing surface coverings and garden coverings have poor hydrophilicity and cannot effectively reduce noise.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is: a preparation method of a hydrophilic porous noise-reducing organic surface covering, which is specifically implemented according to the following steps:

[0006] Step 1, obtain branches and cut the branches to obtain cuttings or particles.

[0007] Step 2: Naturally dry the cutting pieces or cutting grains obtained in Step 1 to form a common organic ground cover;

[0008] Step 3: Prepare an infiltration modification liquid, then perform surface modification on the common organic ground cover formed in Step 2 by spraying or infiltration, and finally obtain a cutting material substrate after pre-drying;

[0009] Step 4: Prepare a pore-forming agent;

[0010] Step 5: Let the cutting material substrate obtained in Step 3 fully absorb the pore-forming agent prepared in Step 4, and then undergo track-type microwave drying to obtain a hydrophilic porous noise-reducing organic ground cover.

[0011] As a preferred technical solution of the present invention, in Step 1, the branches are the products after removing fallen fruits, fallen flowers, leaf stalks, and leaves from garden pruning wastes.

[0012] As a preferred technical solution of the present invention, the width and thickness of the cutting pieces or cutting grains are 0.5 cm - 3 cm, and the length is 1 cm - 8 cm.

[0013] As a preferred technical solution of the present invention, in Step 2, the temperature for natural drying is 18°C - 35°C.

[0014] As a preferred technical solution of the present invention, in Step 3, the infiltration modification liquid is composed of 1% - 2% glycerol, 5% - 7% ethanol, and the balance is water by mass percentage.

[0015] As a preferred technical solution of the present invention, in Step 3, the temperature for pre-drying is 50°C - 70°C, and the time is 10 min - 10 min.

[0016] As a preferred technical solution of the present invention, in Step 4, the pore-forming agent is composed of 3% - 15% ammonium bicarbonate, 2% - 6% ammonium chloride, and the balance is water by mass percentage.

[0017] As a preferred technical solution of the present invention, in Step 5, the moisture content of the cutting material substrate remains at 50% - 80% after fully absorbing the pore-forming agent prepared in Step 4.

[0018] As a preferred technical solution of the present invention, in Step 5, the power of the track-type microwave drying is 100 kw - 140 kw, and the moisture content after track-type microwave drying is 1.5% - 2%.

[0019] The beneficial effects of the present invention are as follows: For the preparation method of a hydrophilic porous noise-reducing organic ground cover of the present invention, a wetting modifier is used to perform surface modification on xylem, which improves the hydrophilicity of xylem vessels and tracheids, making it easier for pore-forming agents to penetrate. Moreover, after laying, the water content is greater than that of ordinary organic covers, which can effectively keep the ground surface moist. The method of using vessels and tracheids to absorb pore-forming agents is combined with microwave to form "micro gas explosion", forming a microporous structure on the vessel wall. Compared with ethanol-water as the reference pore-forming agent and compared with ordinary ground covers, the hydrophilic porous noise-reducing organic ground cover formed by the present invention has a more obvious porous structure and has sound absorption ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a comparison effect diagram of the water contact angle photos before and after the hydrophilic modification of the cutting surface;

[0021] Figure 2 It is a comparative electron microscope micrograph of the hydrophilic porous noise-reducing organic ground cover prepared by the method of the present invention;

[0022] Figure 3 It is a noise reduction comparison diagram of the hydrophilic porous noise-reducing organic ground cover prepared by the method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0023] The following further describes the present invention in detail with reference to the attached drawings and specific embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0024] The present invention will be further described below through examples, but is not limited to the following examples.

[0025] Example 1

[0026] The preparation method of a hydrophilic porous noise-reducing organic ground cover of the present invention is specifically implemented according to the following steps:

[0027] Step 1: After removing fallen fruits, fallen flowers, petioles and leaves from garden pruning waste, the branches are obtained, and the branches are cut into cutting pieces or cutting grains with a width and thickness of 0.5 cm and a length of 1 cm;

[0028] Step 2: The cutting pieces or cutting grains obtained in Step 1 are naturally dried at 18 °C to form an ordinary organic ground cover;

[0029] Step 3: Prepare a wetting modification liquid composed of 1% glycerol, 5% ethanol and 94% water by mass percentage; then, the ordinary organic ground cover formed in Step 2 is surface-modified by spraying or wetting, and finally pre-dried at 50 °C for 20 min to obtain a cutting substrate;

[0030] Step 4, prepare the pore-forming agent; the pore-forming agent is composed of 3% ammonium bicarbonate, 2% ammonium chloride and 95% water by mass percentage;

[0031] Step 5, make the cutting substrate obtained in Step 3 fully absorb the pore-forming agent prepared in Step 4, and keep the moisture content at 50%. Then, it is dried by a 140-kw crawler-type microwave until the water content is 2%, obtaining a hydrophilic porous noise-reducing organic ground cover.

[0032] Example 2

[0033] A preparation method of a hydrophilic porous noise-reducing organic ground cover of the present invention is specifically implemented according to the following steps:

[0034] Step 1, after removing fallen fruits, fallen flowers, leaf stalks and leaves from garden pruning waste, obtain branches, and cut the branches into cutting pieces or cutting grains with a width and thickness of 3 cm and a length of 8 cm;

[0035] Step 2, naturally dry the cutting pieces or cutting grains obtained in Step 1 at 135 °C to form a common organic ground cover;

[0036] Step 3, prepare an infiltration modification liquid composed of 2% glycerol, 7% ethanol and 91% water by mass percentage; then, perform surface modification on the common organic ground cover formed in Step 2 by spraying or infiltration, and finally pre-dry it at 70 °C for 10 min to obtain a cutting substrate;

[0037] Step 4, prepare the pore-forming agent; the pore-forming agent is composed of 15% ammonium bicarbonate, 6% ammonium chloride and 79% water by mass percentage;

[0038] Step 5, make the cutting substrate obtained in Step 3 fully absorb the pore-forming agent prepared in Step 4, and keep the moisture content at 80%. Then, it is dried by a 100-kw crawler-type microwave until the water content is 1.5%, obtaining a hydrophilic porous noise-reducing organic ground cover.

[0039] Example 3

[0040] A preparation method of a hydrophilic porous noise-reducing organic ground cover of the present invention is specifically implemented according to the following steps:

[0041] Step 1, after removing fallen fruits, fallen flowers, leaf stalks and leaves from garden pruning waste, obtain branches, and cut the branches into cutting pieces or cutting grains with a width and thickness of 2 cm and a length of 5 cm;

[0042] Step 2, naturally dry the cutting pieces or cutting grains obtained in Step 1 at 26 °C to form a common organic ground cover;

[0043] Step 3: Prepare an infiltration modification liquid composed of 1.5% glycerol, 6% ethanol, and the balance being water by mass percentage; then perform surface modification on the ordinary organic ground cover formed in Step 2 by spraying or infiltration, and finally pre-dry at 60°C for 15 minutes to obtain a cutting substrate;

[0044] Step 4: Prepare a pore-forming agent; the pore-forming agent is composed of 10% ammonium bicarbonate, 4% ammonium chloride, and 86% water by mass percentage;

[0045] Step 5: After the cutting substrate obtained in Step 3 fully absorbs the pore-forming agent prepared in Step 4 and the moisture content is maintained at 70%, then undergo track-type microwave drying with 120 kw until the water content is 1.7% to obtain a hydrophilic porous noise-reducing organic ground cover.

[0046] In the present invention, xylem infiltration modification is used to increase the hydrophilicity of vessels and tracheids. After microwave treatment, the pore-forming agent completely volatilizes into gas, and a large amount of gas forms "micro gas explosions" in tracheids, resulting in micropores on the surface of cutting chips or cutting grains, forming a surface-porous cover.

[0047] The key technology of the present invention is to use the extrusion cutting chips or cutting grains of garden greening pruning as the substrate of the organic cover, embed tiny gas-producing liquid droplets into the xylem vessels of the substrate, and form "micro gas explosions" under the action of microwave to produce micropores in tracheids, forming an organic ground cover with a porous and interlaced sound-absorbing structure on the surface of the vessel wall, achieving the effect of absorbing low-frequency noise after being laid on the ground surface.

[0048] The hydrophilic mechanism of the present invention is to use a low-molecular-weight composite alcohol solution to increase the stretching degree of hydroxyl groups in the lignin of the cover, thereby promoting the infiltration of the ammonium salt pore-forming agent into the vessels and filling the tracheids.

[0049] Since the decomposition temperature of the ammonium bicarbonate solution is from 36°C to 60°C and the process is relatively long, which is not sufficient to produce a "gas explosion" effect, the pore-forming principle of the present invention is that ammonium chloride decomposes to produce HCl under the action of microwave, further accelerating the rapid decomposition of ammonium bicarbonate to form "micro gas explosions". CO2 will not slowly overflow due to dissolution. After experimental screening of the appropriate proportion of the ammonium salt solution, the acid-base ammonium salts react completely quickly under the action of microwave.

[0050] NH4Cl → NH3↑ + HCl↑

[0051] NH4HCO3 → NH3↑ + CO2↑ + H2O

[0052] NH4HCO3 + HCl → NH4Cl + H2O + CO2↑

[0053] Table 1 Comparison of the sound absorption coefficient α values of different covers at 900 Hz

[0054]

[0055]

[0056] Combined with Figure 1 , from the comparison data, the hydrophilic porous noise-reducing organic surface covering of the present invention is more hydrophilic than the ordinary organic soil covering, and has stronger water absorption in practical applications.

[0057] From the data results in Table 1, it can be seen that with the increase of the laying thickness of the covering of the present invention, it can reach the range of sound-absorbing materials (α>0.2) and ideal sound-absorbing materials (α>0.5).

[0058] Combined with Figure 2 , their magnification factors are all 1.80k, where a is the characterization diagram of the outer wall of the conduit of the ordinary organic covering, b is the characterization diagram of the deep pore channels of the conduit of the ordinary organic covering, c is the characterization diagram of the gas explosion effect on the conduit wall of the covering produced by using 5% ethanol-aqueous solution as the pore-forming agent, and d is the characterization diagram of the gas explosion effect on the conduit wall of the organic covering of the present invention (obtained in Example 2). It can be seen from the microscopic electron microscopy characterization that compared with the ordinary organic soil covering and the covering using ethanol and water as the pore-forming agent with the same microwave treatment, the pore-forming ability of the tracheids is significantly enhanced, changing the smooth surface characteristics of the ordinary organic soil covering and forming noise-reducing pores.

[0059] Combined with Figure 3 , Figure 3 is in a simulated environmental temperature of 19°C, relative humidity of 50%, atmospheric pressure of 101325 Pa, air density of 1.2061 kg / m 3 , sound speed of 342.651 m / s, air characteristic impedance of 413.273 Pa·s / m, laying thickness of the covering of 1 cm, and the sound absorption coefficient α of the impedance large tube is tested for the audible mid-low frequency noise in the range of 20 Hz - 1200 Hz. It can be seen that the sound absorption ability of the hydrophilic porous noise-reducing organic surface covering of the present invention (obtained in Example 2) is higher than that of the ordinary organic covering, and the sound absorption coefficient for the low frequency of 400 Hz to the mid-frequency of 1200 Hz reaches above 0.2.

Claims

1. A preparation method of a hydrophilic porous noise-reducing organic ground cover, characterized in that, The implementation is specifically carried out according to the following steps: Step 1: Obtain the branches and cut them to get cut pieces or cut grains; Step 2: Naturally dry the cut pieces or cut grains obtained in Step 1 to form a common organic ground cover; Step 3: Prepare an infiltration modification liquid, and then perform surface modification on the common organic ground cover formed in Step 2 by spraying or infiltration. Finally, obtain a cut material substrate after pre-drying; Step 4: Prepare a pore-forming agent; Step 5: Make the cut material substrate obtained in Step 3 fully absorb the pore-forming agent prepared in Step 4, and then undergo track-type microwave drying to obtain a hydrophilic porous noise-reducing organic ground cover.

2. The preparation method of the hydrophilic porous noise-reducing organic ground cover according to claim 1, characterized in that, In Step 1, the branches are the products after removing fallen fruits, fallen flowers, leaf stalks and leaves from garden pruning wastes.

3. The preparation method of the hydrophilic porous noise-reducing organic surface covering according to claim 2, characterized in that, In Step 1, the width and thickness of the cut pieces or cut grains are 0.5 cm - 3 cm, and the length is 1 cm - 8 cm.

4. The preparation method of the hydrophilic porous noise-reducing organic surface covering according to claim 1, characterized in that In Step 2, the temperature for natural drying is 18°C - 35°C.

5. The preparation method of the hydrophilic porous noise-reducing organic surface covering according to claim 3, characterized in that, In Step 3, the infiltration modification liquid is composed of 1% - 2% glycerol, 5% - 7% ethanol and the balance is water by mass percentage.

6. The preparation method of the hydrophilic porous noise-reducing organic surface covering according to claim 4, wherein In Step 3, the temperature for pre-drying is 50°C - 70°C, and the time is 10 min - 20 min.

7. The preparation method of the hydrophilic porous noise-reducing organic surface covering according to claim 5, wherein, In Step 4, the pore-forming agent is composed of 3% - 15% ammonium bicarbonate, 2% - 6% ammonium chloride and the balance is water by mass percentage.

8. The preparation method of the hydrophilic porous noise-reducing organic surface covering according to claim 6, wherein, In Step 5, the moisture content of the cut material substrate remains at 50% - 80% after fully absorbing the pore-forming agent prepared in Step 4.

9. The preparation method of the hydrophilic porous noise-reducing organic surface covering according to claim 7, characterized in that, In Step 5, the power of the track-type microwave drying is 100 kw - 140 kw, and the moisture content after track-type microwave drying is 1.5% - 2%.

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