A method for preparing fireproof and moistureproof solid wood slices

Abstract

This invention discloses a method for preparing fire-resistant and moisture-proof solid wood chips. Lignin with high aromatic ether and high nitrogen content is separated using a benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent system. An appropriate amount of chitin and a small amount of glutaraldehyde are added to the separated lignin solution, and then backfilled into the interior and surface of the lignin-treated wood chips via vacuum impregnation and adsorption. Combined with hot-pressing technology, high-density fire-resistant and moisture-proof solid wood chips are obtained. The water vapor transmission rate of the fire-resistant and moisture-proof solid wood chips is 8.1 g / m³ at 38℃ and 90% relative humidity. 2 / d, air permeability 5.6cm 3 / cm 2 The moisture absorption rate is 3.2%, and the peak heat release rate is 122.5 kW / m². 2 The total heat release is 15.2 MJ / m³. 2 The total amount of smoke produced was 0.6m³. 2 .

Description

Technical Field

[0001] This invention belongs to the field of solid wood material preparation technology, specifically relating to a method for preparing fire-resistant and moisture-proof solid wood chips. Background Technology

[0002] The production of functional materials from renewable forest resources is gaining increasing attention. Wood, the Earth's most abundant renewable resource, is widely used in construction, furniture, and packaging materials. However, the poor fire resistance and high moisture absorption of raw wood limit its application in various fields. Researchers have employed various processes to improve the fire and moisture resistance of materials, such as surface spraying with fire-retardant paint that decomposes into phosphoric acid at high temperatures, and impregnation with inorganic silicate and resin materials. However, these external additives significantly impact the recyclability and environmental friendliness of the wood itself. This method utilizes solvent separation to extract the hydrophobic and flame-retardant properties of lignin with high aromatic ether and nitrogen content, as well as the excellent film-forming properties of chitosan. Leveraging the porous structure of wood and combining it with hot-pressing technology, high-density fire-resistant and moisture-proof solid wood chips are produced. Summary of the Invention

[0003] In view of the shortcomings of existing technologies, such as poor fire resistance, high moisture absorption, and the fact that external additives can greatly affect the recyclability and environmental performance of the wood itself, this invention provides a method for preparing fireproof and moisture-proof solid wood chips.

[0004] To achieve the above-mentioned objectives, the present invention employs the following technical solution:

[0005] A method for preparing fire-resistant and moisture-proof solid wood chips includes the following steps:

[0006] Step 1: After treating the solid wood chips with a benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent system, acid precipitation was used to separate lignin with high aromatic ether content and high nitrogen content;

[0007] Step 2: Add chitin and glutaraldehyde to the separated lignin solution to obtain solution A;

[0008] Step 3: Solution A is backfilled into the interior and surface of the delignified wood chips by vacuum impregnation and adsorption.

[0009] Step 4: Obtain high-density fire-resistant and moisture-proof solid wood chips through hot pressing.

[0010] Furthermore, in the first step, the molar ratio of the benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent system is 1:4 to 1:8, and the solid-liquid ratio is 1:8; the treatment temperature of the benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent system is 100℃, and the treatment time is 5h.

[0011] Furthermore, the lignin with high aromatic ether content and high nitrogen content is separated from the lignin dissolved in benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent by acid precipitation, and then the lignin with high aromatic ether content and high nitrogen content is dispersed in 1% NaOH solution to obtain the separated lignin solution.

[0012] Furthermore, in the second step, the amount of chitin added to the separated lignin solution is 1-4% of the weight of the wood chips, and the amount of glutaraldehyde added is 0.1-0.4% of the weight of the wood chips.

[0013] Furthermore, the chitin is chitosan.

[0014] Furthermore, in the third step, the vacuum impregnation adsorption temperature is 25°C and the time is 24 hours.

[0015] Furthermore, in the fourth step, the hot pressing temperature is 105℃, the pressure is 6MPa, and the time is 6h.

[0016] Furthermore, the wood chips are linden wood chips or pine wood chips.

[0017] Beneficial effects

[0018] 1. This invention utilizes a benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent system to separate lignin with high aromatic ether content and high nitrogen content. An appropriate amount of chitin and a small amount of glutaraldehyde are added to the separated lignin solution, and the solution is backfilled into the interior and surface of the lignin-de-lignin board through vacuum impregnation and adsorption. Combined with hot pressing technology, high-density fireproof and moisture-proof solid wood chips are obtained.

[0019] 2. The fire-resistant and moisture-proof solid wood veneer obtained by this invention has a water vapor transmission rate of 8.1 g / m³ at 38℃ and 90% relative humidity. 2 / d, air permeability 5.6cm 3 / cm 2 The moisture absorption rate is 3.2%, and the peak heat release rate is 122.5 kW / m². 2 The total heat release is 15.2 MJ / m³. 2 The total amount of smoke produced was 0.6m³. 2 .

[0020] 3. The fireproof and moisture-proof solid wood veneer prepared by this invention not only has good fireproof and moisture-proof effects, but also has a simple structure, is easy to manufacture, and has low cost. At the same time, it is environmentally friendly and suitable for widespread use in interior wall decoration of various buildings, fire door frame production, and exterior surface decoration of home facilities. It can also be used as a substitute for metal and glass products in the production and manufacturing of various frames. Attached Figure Description

[0021] Figure 1These are scanning electron microscope (SEM) images of the original linden wood chips and the fire-resistant and moisture-proof linden wood chips of the present invention. In the images, A1 is a radial SEM image of the original linden wood chips, A2 is an axial SEM image of the original linden wood chips, B1 is a radial SEM image of the fire-resistant and moisture-proof linden wood chips, and B2 is an axial SEM image of the fire-resistant and moisture-proof linden wood chips.

[0022] Figure 2 These are the cone calorimetric data for the original linden wood chips and fire-resistant and moisture-proof linden wood chips used in this invention. Figure 2 A represents the heat release rate (HRR). Figure 2 B represents the total heat release (THR). Figure 2 C represents the total amount of smoke (TSP). Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the embodiments. Reagents or instruments used without a specified manufacturer are considered to be conventional products that can be purchased on the market.

[0024] The solid wood chips used in the following examples are linden wood chips and pine wood chips with dimensions of 100mm×100mm×3mm, respectively. Chitosan was purchased from Sigma-Aldrich, and other chemicals were purchased from Sinopharm Chemical Reagent Co., Ltd.

[0025] Preparation method of benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent: benzyltrimethylammonium chloride and hydroxyethyl ethylenediamine are stirred in an oil bath at 100℃ until completely dissolved and then set aside.

[0026] Solvent treatment method for wood chips: After heating the benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent oil bath to 100°C, the solid wood chips are completely immersed in the solvent. After keeping it at this temperature for 5 hours, the wood chips are removed and the residual chemicals are removed with hot water before use.

[0027] Preparation method of vacuum impregnation adsorption solution: The lignin dissolved in benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent is separated by acid precipitation, and then dispersed in 1% NaOH solution. Appropriate amounts of chitosan and glutaraldehyde are added and the solution is dispersed evenly before use.

[0028] Wood chip vacuum impregnation adsorption method: Place the wood chips washed with hot water into a glass container with vacuum impregnation adsorption solution added, and place the glass container in a vacuum desiccator at 25°C for 24 hours.

[0029] Wood chip hot pressing method: The wood chips that have been vacuum impregnated and adsorbed are placed in a square steel mold, and the hot pressing temperature is 105℃, the pressure is 6MPa, and the time is 6h.

[0030] Example 1

[0031] A method for preparing fire-resistant and moisture-proof linden wood chips, comprising the following steps:

[0032] Step 1: After treating the linden wood chips with benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent (molar ratio 1:6) at 100℃ for 5 hours, wash off the residual chemicals with hot water and set aside for later use;

[0033] Step 2: Use acid precipitation to separate the lignin dissolved in benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent, and then disperse it in 1% NaOH solution to obtain the separated lignin solution;

[0034] Step 3: Add 2% chitosan and 0.2% glutaraldehyde to the separated lignin solution to obtain solution A;

[0035] Step 4: At 25℃, vacuum impregnation adsorption is performed for 24 hours to backfill solution A into the interior and surface of the delignified linden wood chips;

[0036] Step 5: Hot pressing at 105℃, pressure of 6MPa, and time of 6 hours to obtain fireproof and moisture-proof linden wood chips.

[0037] The water vapor transmission rate of wood chips at 38°C and 90% relative humidity was determined according to the TAPPI T448om-09 standard method. The moisture absorption rate of wood chips was determined according to the LY / T 3036-2018 standard method. The gas transmission rate of wood chips was determined according to the GB1038.1-2022 standard method. The combustion performance of wood chips was determined using a cone calorimeter according to the ISO 5660-2015 standard method.

[0038] Experimental results:

[0039] As shown in Tables 1-1 and 1-2, the density of the original linden wood chips is 0.5 g / m³. 2 At 38℃ and 90% relative humidity (RH), the water vapor transmission rate is 128.0 g / m³. 2 / d, air permeability is 64.0cm 3 / m 2 The moisture absorption rate is 21.3% per second. Under the same test conditions, the density of linden wood chips increased to 1.3 g / m³ after fire-retardant and moisture-proof treatment. 2 The water vapor transmission rate decreased to 8.1 g / m. 2 / d, the air permeability decreased to 5.6cm. 3 / m 2 / s, the moisture absorption rate decreased to 6.2%. This is mainly because after lignin fills the cell cavity, the high aromatic ether structure in it can effectively increase the cross-linking between fibers and between fibers and lignin under hot pressing. With the synergistic effect of the polymer chitosan, the porosity of the material can be effectively reduced and the density of the material can be increased. Combined with the hydrophobic effect of lignin, its barrier efficiency against water, water vapor and air is increased, the permeability is significantly reduced, and the moisture-proof performance of the material is significantly improved.

[0040] The nitrogen element on lignin allows it to release non-combustible gases during combustion, diluting the oxygen concentration in the air. This, combined with the material's air-barrier effect, increases its peak heat release rate from 435.4 kW / m³. 2 Reduced to 122.5kW / m 2 The total heat release was 48.1 MJ / m 2 Reduced to 15.2 MJ / m 2 The total amount of smoke generated was 2.0m³. 2 Reduced to 0.6m 2 The fire resistance of the material is significantly improved.

[0041] Table 1-1 Moisture-proof Performance Indicators of Fire-resistant and Moisture-proof Linden Wood Chips

[0042]

[0043] Table 1-2 Fire Resistance Performance Indicators of Linden Wood Chips (Fireproof and Moisture-proof)

[0044]

[0045] Example 2

[0046] A method for preparing fire-resistant and moisture-proof pine chips, comprising the following steps:

[0047] Step 1: Pine wood chips are treated with benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent (molar ratio 1:6) at 100℃ for 5 hours, and then washed with hot water to remove residual chemicals before use.

[0048] Step 2: Use acid precipitation to separate the lignin dissolved in benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent, and then disperse it in 1% NaOH solution to obtain the separated lignin solution;

[0049] Step 3: Add 2% chitosan and 0.2% glutaraldehyde to the separated lignin solution to obtain solution A;

[0050] Step 4: At 25℃, vacuum impregnation adsorption is performed for 24 hours to backfill solution A into the interior and surface of the delignified linden wood chips;

[0051] Step 5: Hot-pressing at 105℃, 6MPa, and for 6 hours yields fire-resistant and moisture-proof pine chips. The water vapor transmission rate of the wood chips at 38℃ and 90% relative humidity is determined according to the TAPPI T448om-09 standard method. The moisture absorption rate of the wood chips is determined according to the LY / T3036-2018 standard method. The gas transmission rate of the wood chips is determined according to the GB1038.1-2022 standard method. The combustion performance of the wood chips is determined using a cone calorimeter according to the ISO 5660-2015 standard method.

[0052] Experimental results:

[0053] As shown in Tables 2-1 and 2-2, the density of the raw pine chips is 0.4 g / m³. 2 At 38℃ and 90% relative humidity (RH), the water vapor transmission rate is 116.0 g / m³. 2 / d, air permeability 75.0cm 3 / m 2 The moisture absorption rate is 20.3% per second. Under the same test conditions, the density of linden wood chips increased to 1.2 g / m³ after fire-retardant and moisture-proof treatment. 2 The water vapor transmission rate decreased to 10.2 g / m. 2 / d, air transmittance decreased to 9.6cm 3 / m 2 / s, the moisture absorption rate is reduced to 2.6%. The material's barrier efficiency against water, water vapor and air is increased, the permeability is significantly reduced, and the material's moisture-proof performance is significantly improved.

[0054] The nitrogen on the lignin releases non-combustible gases, which, combined with the material's air-barrier effect, increases its peak heat release rate from 655.4 kW / m³. 2 Reduced to 192.2 kW / m 2 The total heat release increased from 63.1 MJ / m 2 Reduced to 18.9 MJ / m 2 The total amount of smoke generated was 2.5m. 2 Reduced to 0.8m 2 The fire resistance of the material is significantly improved.

[0055] Table 2-1 Fire-resistant and moisture-proof performance indicators of pine chips

[0056]

[0057] Table 2-2 Fire-resistant and moisture-proof pine chips fire resistance performance indicators

[0058]

[0059] Example 3

[0060] The effects of the molar ratio of benzyltrimethylammonium chloride to hydroxyethyl ethylenediamine solvent and the composition of the vacuum impregnation solution on the properties of wood chips were investigated using the following steps:

[0061] Linden wood chips were treated with benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent at different molar ratios (1:4, 1:6, 1:8) for 5 hours, and then rinsed with hot water to remove residual chemicals before use. Lignin dissolved in the benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent was separated by acid precipitation and then dispersed in a 1% NaOH solution, with 1%, 2%, and 4% chitosan and 0.1%, 0.2%, and 0.4% glutaraldehyde added, respectively. The cleaned wood chips were then subjected to vacuum impregnation in the solution for 24 hours, followed by hot pressing for 6 hours (105℃, 6MPa) to obtain fire-resistant and moisture-proof linden wood chips. The water vapor transmission rate of the wood chips at 38℃ and 90% relative humidity was determined according to the TAPPI T448om-09 standard method. The moisture absorption rate of the wood chips was determined according to the LY / T 3036-2018 standard method. The gas permeability of wood chips was determined according to the standard method of GB1038.1-2022, and the combustion performance of wood chips was determined according to the standard method of ISO5660-2015.

[0062] Experimental results:

[0063] As shown in Tables 3-1 to 3-4, the solvent molar ratio and the composition of the vacuum impregnation solution have a significant impact on the fire and moisture resistance of solid wood chips. The preferred solvent molar ratio is 1:6, and the preferred vacuum impregnation solution composition contains 2% chitosan and 0.2% glutaraldehyde.

[0064] Table 3-1 Effect of solvent molar ratio on the moisture-proof performance of linden wood chips

[0065]

[0066] Table 3-2 Effect of Solvent Molar Ratio on the Fire Retardant Properties of Linden Wood Chips

[0067]

[0068] Table 3-3 Effect of Vacuum Impregnation Solution Composition on the Moisture Resistance of Linden Chips

[0069]

[0070] Table 3-4 Effect of Vacuum Impregnation Solution Composition on the Fire and Moisture Resistance of Linden Chips

[0071]

[0072] The scope of protection of this invention is not limited to the above embodiments. Variations and advantages that can be conceived by those skilled in the art without departing from the spirit and scope of the inventive concept are included in this invention and are protected by the appended claims.

Claims

1. A method for preparing fire-resistant and moisture-proof solid wood chips, characterized in that, Includes the following steps: Step 1: After treating the solid wood chips with a benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent system, acid precipitation was used to separate lignin with high aromatic ether content and high nitrogen content; Step 2: Disperse the separated lignin solution in a 1% NaOH solution, then add chitosan and glutaraldehyde to obtain solution A; Step 3: Solution A is backfilled into the interior and surface of the delignified wood chips by vacuum impregnation and adsorption. Step 4: Obtain high-density fire-resistant and moisture-proof solid wood chips through hot pressing.

2. The method for preparing fire-resistant and moisture-proof solid wood chips according to claim 1, characterized in that: In the first step, the molar ratio of the benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent system is 1:4 to 1:8, and the solid-liquid ratio is 1:8; the treatment temperature of the benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent system is 100 °C, and the treatment time is 5 h.

3. The method for preparing fire-resistant and moisture-proof solid wood chips according to claim 1, characterized in that: The lignin with high aromatic ether content and high nitrogen content was separated by acid precipitation from the lignin dissolved in benzyltrimethylammonium chloride-hydroxyethyl ethylenediamine solvent, and then the lignin with high aromatic ether content and high nitrogen content was dispersed in a 1% NaOH solution to obtain the separated lignin solution.

4. The method for preparing fire-resistant and moisture-proof solid wood chips according to claim 1, characterized in that: In the second step, the amount of chitosan added to the separated lignin solution is 1-4% of the weight of the wood chips, and the amount of glutaraldehyde added is 0.1-0.4% of the weight of the wood chips.

5. The method for preparing fire-resistant and moisture-proof solid wood chips according to claim 1, characterized in that: In the third step, the vacuum impregnation adsorption temperature is 25°C and the time is 24 hours.

6. The method for preparing fire-resistant and moisture-proof solid wood chips according to claim 1, characterized in that: In the fourth step, the hot pressing temperature is 105 ℃, the pressure is 6 MPa, and the time is 6 h.

7. The method for preparing fire-resistant and moisture-proof solid wood chips according to claim 1, characterized in that: The wood chips are either linden wood chips or pine wood chips.

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