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CN-122008371-A - Modified poplar bark veneer with flame-retardant and mildew-proof functions and manufacturing method thereof

CN122008371ACN 122008371 ACN122008371 ACN 122008371ACN-122008371-A

Abstract

The invention discloses a modified poplar bark veneer with flame-retardant and mildew-proof functions and a manufacturing method thereof. The method comprises the steps of preprocessing poplar bark to remove lignin and open cell wall pits, preparing a modifying solution by using phytic acid, aminosilane modified chitosan and a metal cation cross-linking agent, forming a gradient protection structure in the poplar bark by vacuum-pressure impregnation, attaching the modified poplar bark to a base material after flexible drying, and performing hot press molding at 120-150 ℃. The esterification and polycondensation reaction is triggered under high temperature and high pressure, and a P-N-Si hybridization network is built in situ on the cell wall of the wood. The P-N-Si network of the veneer prepared by the invention contains phosphorus, nitrogen and silicon elements and is covalently combined with hydroxyl groups of the cell walls of the wood, so that the high-efficiency integration of flame retardance, mildew resistance and interface gluing enhancement of the poplar bark is successfully realized, and the defects of easy loss and strength reduction of the traditional modification are overcome.

Inventors

  • ZENG XINXIN
  • DAI ZHIHAO

Assignees

  • 抚州豪欣装饰新材料有限公司

Dates

Publication Date
20260512
Application Date
20260407

Claims (7)

  1. 1. The manufacturing method of the modified poplar bark veneer with the flame-retardant and mildew-proof functions is characterized by comprising the following steps of: step 1, pretreating a poplar bark raw material to remove lignin obstruction and opening wood cell wall pits; step 2, taking phytic acid as an acidic element, amino silane modified chitosan as an alkaline element, adding metal cations as a crosslinking bridging agent, and uniformly mixing to form a stable colloid system modified liquid; Step 3, placing the poplar bark pretreated in the step 1 into the modified liquid prepared in the step 2, and carrying out vacuum-pressure impregnation treatment to enable small molecules in the modified liquid to enter the cell wall, and enabling macromolecules to reside in the cell cavity so as to form a gradient protection structure in the poplar bark; Step 4, drying the soaked poplar bark, controlling the drying speed to enable the modifier entering the cell wall and residing in the cell cavity to be subjected to primary crystallization, and preventing the modifier from migrating and surface crystallization during subsequent hot pressing; And 5, attaching the flexible dried modified poplar bark to a base material, performing hot pressing at the temperature of 120-150 ℃, and utilizing high temperature to trigger esterification reaction and siloxane polycondensation reaction to construct a P-N-Si hybrid network in situ on the cell wall of the wood, so as to prepare the flame-retardant, mildew-proof and reinforced integrated modified poplar bark veneer.
  2. 2. The method for manufacturing the modified poplar bark veneer with the flame-retardant and mildew-proof functions, which is characterized by comprising the following steps of 1, placing a poplar bark raw material into a mixed solution for soaking, wherein the mixed solution comprises hydrogen peroxide with the mass concentration of 1% -5% and glacial acetic acid with the mass concentration of 1% -3%, and the soaking time is 30-120 minutes.
  3. 3. The method for manufacturing the modified poplar bark veneer with the flame-retardant and mildew-resistant functions, which is characterized in that in the step 2, metal cations are selected from one or a combination of more of Mg2 + 、Zn² + and Ca2 + , and the molar ratio of phytic acid to aminosilane modified chitosan to metal cations is (1-3): (1-2): (0.1-0.5).
  4. 4. The method for manufacturing the modified poplar bark veneer with the flame-retardant and mildew-proof functions, which is characterized in that in the step 3, the vacuum-pressure impregnation process comprises the steps of firstly vacuumizing for 15-30 minutes under the pressure of minus 0.08MPa to minus 0.1MPa, then injecting a modifying liquid, pressurizing to 0.5MPa to 1.0MPa, maintaining the pressure for 60-120 minutes, and finally releasing the pressure and taking out the poplar bark.
  5. 5. The method for manufacturing the modified poplar bark veneer with the flame-retardant and mildew-proof functions, which is characterized in that in the step 4, the flexible drying is performed by adopting a stepped heating drying method, the initial temperature is controlled to be 40-50 ℃, and then the temperature is increased to 70-85 ℃ at the rate of 2-5 ℃ per minute until the water content of the poplar bark is reduced to 8-12%.
  6. 6. The method for manufacturing the modified poplar bark veneer with the flame-retardant and mildew-resistant functions, which is characterized in that in the step 5, the hot press forming pressure is 1.0-2.5 MPa, the hot press time is 3-8 minutes, and the base material comprises one of a density board, a shaving board, a plywood and a solid wood board.
  7. 7. A modified poplar bark veneer with flame-retardant and mildew-proof functions is characterized by comprising a base material and a modified poplar bark attached to the base material, wherein the modified poplar bark is internally provided with a gradient protection structure, a P-N-Si hybrid network is formed in situ on the cell wall of the modified poplar bark, the P-N-Si hybrid network comprises phosphorus, nitrogen and silicon elements and is covalently combined with hydroxyl groups on the cell wall of the poplar bark, the P-N-Si hybrid network is formed by esterification and polycondensation reactions of phytic acid serving as an acid element, aminosilane modified chitosan serving as an alkaline element and one or more metal cations selected from Mg2 + 、Zn² + and Ca2 + serving as a crosslinking bridging agent.

Description

Modified poplar bark veneer with flame-retardant and mildew-proof functions and manufacturing method thereof Technical Field The invention relates to the technical field of wood processing and modification, in particular to a modified poplar bark veneer with flame-retardant and mildew-proof functions and a manufacturing method thereof. Background As a common fast-growing tree species, the poplar has the characteristics of short growth period, rich resources, easiness in rotary cutting processing and the like, and is widely applied to artificial board surface facing materials (wood veneer). However, poplar has the defects of lower natural density, high porosity and more nutrient substances, is inflammable and easy to damp and mould in the actual use process, and limits the application of the poplar in the fields of building decoration, furniture manufacturing and the like. In the prior art, the wood is generally impregnated with flame retardants containing phosphorus, nitrogen, boron and other elements and various mildew inhibitors to improve the flame retardance and mildew resistance of the wood. However, the conventional physical impregnation method has the defects that the water-soluble agent is not chemically combined with the internal groups of the wood, the agent is easy to migrate and run off in a humid environment, the flame retardant and mildew-proof effects are attenuated with time, and if the surface coating treatment is adopted, the agent is prevented from running off to a certain extent, but the natural texture of the wood is covered, and the visual and tactile effects of the veneer finish are lost. In addition, the wood treated by the anti-corrosion and flame-retardant agent often occupies active groups on the surface of the wood or forms an isolation layer on the surface, so that permeation and solidification of the adhesive in subsequent processing are hindered, the bonding strength of the modified veneer is reduced when the modified veneer is in hot pressing with the surface of the base material, and quality problems such as glue opening and bubbling are easy to occur. Disclosure of Invention The invention aims to solve the technical problems that an anti-corrosion and flame-retardant agent in the existing modified wood is easy to run off and the bonding strength is reduced after modification. The technical aim of the invention is realized by the following technical scheme that the manufacturing method of the modified poplar bark veneer with the flame-retardant and mildew-proof functions comprises the following steps: step 1, pretreatment; pretreating poplar bark raw materials to remove lignin obstruction and open wood cell wall pits; step 2, preparing a modifying liquid; taking phytic acid as an acidic element, amino silane modified chitosan as an alkaline element, adding metal cations as a crosslinking bridging agent, and uniformly mixing to form a stable colloid system modified liquid; Step 3, vacuum-pressure impregnation; Placing the poplar bark pretreated in the step 1 into the modified liquid prepared in the step 2, and carrying out vacuum-pressure impregnation treatment to enable small molecules in the modified liquid to enter the cell wall, and enabling macromolecules to stay in the cell cavity so as to form a gradient protection structure in the poplar bark; step 4, flexible drying; Drying the soaked poplar bark, controlling the drying speed to enable the modifier entering the cell wall and residing in the cell cavity to be subjected to primary crystallization, and preventing the modifier from migrating and surface crystallization during subsequent hot pressing; step 5, hot press molding; And attaching the flexible dried modified poplar bark to a base material, performing hot pressing at the temperature of 120-150 ℃, and utilizing high temperature to trigger esterification reaction and siloxane polycondensation reaction to construct a P-N-Si hybrid network on the wood cell wall in situ to prepare the flame-retardant, mildew-proof and reinforced integrated modified poplar bark veneer. In the step 1, the poplar bark raw material is placed in a mixed solution for soaking, wherein the mixed solution comprises hydrogen peroxide with the mass concentration of 1% -5% and glacial acetic acid with the mass concentration of 1% -3%, and the soaking time is 30-120 minutes. In the step 2, the metal cations are selected from one or a combination of more than one of Mg2 +、Zn²+ and Ca2 +, and the molar ratio of the phytic acid to the aminosilane modified chitosan to the metal cations is (1-3): 1-2): 0.1-0.5. In the step 3, the vacuum-pressure impregnation process is that firstly vacuumizing for 15-30 minutes under the pressure of minus 0.08MPa to minus 0.1MPa, then injecting the modifying liquid, pressurizing to 0.5MPa to 1.0MPa, maintaining the pressure for 60-120 minutes, and finally releasing the pressure and taking out the poplar bark. Further, in the step 4, the flexible drying adopts a step h