A modified polymer sealing material and a method for preparing a particleboard substrate

Abstract

This invention belongs to the field of particleboard processing technology and discloses a modified polymer sealing material and a method for preparing a particleboard substrate. The modified polymer sealing material is composed of a matrix resin, modified filler, toughening agent, curing agent, moisture-proofing agent, and environmentally friendly solvent, achieving a three-dimensional connection of "resin-filler-wood fiber" to solve the problem of traditional filler agglomeration. The toughening agent bonds to the cross-linked network, improving the material's elongation at break. A hydrophobic film is formed in the moisture-proofing agent, ultimately achieving multi-dimensional functions of "penetration-filling-protection-reinforcement." Each step works synergistically to ensure a tight bond between the sealing layer and the board edge. Controlled stirring parameters during material preparation ensure uniform dispersion; coating penetration ensures full pore filling; segmented curing balances shaping and cross-linking effects; and post-processing and testing ensure dimensional accuracy and performance standards. The material can be customized to specific scenarios, making it suitable for humid environments such as furniture manufacturing and interior decoration, and possesses industrial-scale promotion value.

Description

Technical Field

[0001] This invention belongs to the field of particleboard processing technology, specifically a modified polymer sealing material and a method for preparing a particleboard substrate. Background Technology

[0002] Particleboard is widely used in furniture manufacturing and interior decoration due to its low cost and good processing performance. However, the edges of the board are the transition area between the core layer and the surface. The particle size of the chips is large (1-3mm), the adhesive content is low (8%-10%), and there are a large number of interconnected pores (pore size 100-500nm). It is easily damaged by humid environments: moisture penetration causes the edge expansion rate to reach 5%-15%, adhesive hydrolysis reduces the bonding strength by 30%-50%, and it is also easy to breed mold, which harms air quality. Existing moisture-proof solutions have defects: PVC edge banding has poor compatibility with wood fibers and is easy to fall off after 1-2 years, with an expansion rate of more than 8% after 24 hours of soaking; ordinary moisture-proof paint cannot penetrate the pores, the cracking rate at low temperature of -20℃ exceeds 15%, and the VOCs content exceeds 300g / L; wood edge banding is expensive and difficult to use on a large scale.

[0003] Patent 120904835A discloses an ultra-high strength epoxy structural adhesive for wind power hybrid towers and its preparation method. This patent uses only a single bisphenol A type epoxy resin matrix system, which is rigid but lacks toughness. If the particleboard size changes, the adhesive layer may fail due to internal cracking or debonding. The use of silica powder or alumina powder is a conventional function of traditional fillers. The coupling agent is added as an independent component, and the interface modification effect with the filler and resin depends on the uniformity of the mixing process. The interface bonding is weak, and the effect is not ideal. It does not consider moisture-proof and mildew-proof functions, and the colloid has no inhibitory function. It has many problems and cannot be widely used.

[0004] In summary, while adhesive sealants are indeed used in particleboard processing technology, they still suffer from problems such as incompatibility between rigid bonding and materials, insufficient durability and moisture resistance, and poor process adaptability. Therefore, it is of great significance to develop a technology that uses sealing materials to seal the edges of particleboard to improve moisture resistance, bonding strength, weather resistance, and environmental friendliness. Summary of the Invention

[0005] The purpose of this invention is to provide a modified polymer sealing material. This modified polymer sealing material is composed of a matrix resin, modified filler, toughening agent, curing agent, moisture-proofing agent, and environmentally friendly solvent. The matrix resin is a blend of epoxy resin E-44 and polyurethane resin; the former forms high-strength chemical bonds with wood fibers, while the latter possesses elasticity and water resistance. The modified filler is modified with silane coupling agent KH-550 to achieve a three-dimensional connection between resin, filler, and wood fibers, solving the problem of traditional filler agglomeration. The toughening agent, a polyether polyol containing active hydroxyl groups, reacts and bonds with the polyurethane to form a cross-linked network, synergistically improving the material's elongation at break with dioctyl phthalate. The moisture-proofing agent, an organosilicon waterproofing agent, forms a hydrophobic film, while nano-zinc oxide has antibacterial, UV absorption, and curing catalytic functions. Ultimately, it achieves a multi-dimensional function of "penetration-filling-protection-reinforcement."

[0006] Another object of the present invention is to provide a method for preparing a particleboard substrate. The method involves spraying a modified polymer sealing material onto the edge surface of a particleboard, followed by curing and polishing to obtain the particleboard substrate.

[0007] The objective of this invention is achieved through the following solution: A modified polymer sealing material, the sealing material comprising the following components in parts by weight: 40-60 parts of matrix resin, 20-30 parts of modified filler, 5-10 parts of toughening agent, 3-6 parts of curing agent, 2-5 parts of moisture-proofing agent, and 5-10 parts of solvent; the matrix resin is a compound of epoxy resin E-44 and polyurethane resin in a mass ratio of 1:(1-1.5).

[0008] Preferably, the sealing material comprises the following components in parts by weight: 45-55 parts of matrix resin, 25-30 parts of modified filler, 8-10 parts of toughening agent, 5-6 parts of curing agent, 3-5 parts of moisture-proofing agent, and 8-10 parts of solvent; the matrix resin is a mixture of epoxy resin E-44 and polyurethane resin in a mass ratio of 1:(1-1.5).

[0009] Epoxy resin E-44 contains multiple epoxy groups, which, after reacting with the curing agent, form a highly cross-linked three-dimensional rigid network, improving the material's high modulus, high strength, and dimensional stability. The epoxy groups in the epoxy resin and the hydroxyl groups generated after curing together form hydrogen bonds with the abundant hydroxyl groups on the surface of wood fibers, with a strength higher than physical adsorption force, achieving an essential and firm bond between the adhesive layer and the wood. Polyurethane consists of soft segments (polyether / polyester polyol) and hard segments (isocyanate and chain extender). The soft segments provide high elasticity and high elongation at break, while the hard segments provide physical cross-linking points. When the material is subjected to external force, the flexible segments of polyurethane can absorb and dissipate energy through segment extension, slippage, and orientation, thereby buffering stress, avoiding the initiation and propagation of cracks caused by stress concentration, and improving the material's impact resistance, fatigue resistance, and deformation adaptability. Polyurethane resin itself has good hydrophobicity and hydrolysis resistance, which can block water molecule pathways and enhance the overall material's moisture resistance. The synergistic compounding of the two can form an interpenetrating polymer network, improving the material's strength, rigidity, toughness, and load-bearing capacity.

[0010] Preferably, the modified filler is one or both of nano-silica and mica powder modified with a silane coupling agent; the silane coupling agent is KH-550.

[0011] Nano-silica and mica powder have extremely high specific surface area and rigidity. When uniformly dispersed in the resin matrix, they can effectively hinder the movement of polymer chain segments and act as physical cross-linking points, improving the modulus, hardness, wear resistance and thermal stability of the material. The silanol groups generated after the alkoxy groups of KH-550 hydrolyze react with the hydroxyl groups on the surface of the filler to form Si-O-Si bonds, thereby coating the surface of the filler with an organic molecular layer and reducing its surface energy. The amino groups at the other end of the KH-550 molecule undergo ring-opening reactions with the epoxy groups of the epoxy resin, and at the same time react with the isocyanate groups in the polyurethane prepolymer to form a three-dimensional connection of "resin-filler-wood fiber", which improves the interfacial bonding strength.

[0012] Preferably, the toughening agent is a mixture of dioctyl phthalate and polyether polyol in a mass ratio of 1:(1-1.5); the moisture-proofing agent is a mixture of organosilicon waterproofing agent and nano zinc oxide in a mass ratio of (1-2):1.

[0013] Polyether polyols contain terminal hydroxyl groups, which can react directly with polyurethane prepolymers. Their chemical bonds are locked in the cross-linked network to form flexible segments, preventing the migration of small molecule plasticizers and improving long-term toughening effect. Dioctyl phthalate is a small molecule intercalated in the polymer macromolecular chain, increasing the interchain spacing, weakening intermolecular forces, and making the chain segments easier to move under external force. Polyether polyols provide a stable and flexible network skeleton, while dioctyl phthalate provides efficient chain segment mobility, improving the elongation at break of the material.

[0014] During the curing process, organosilicon molecules migrate to the material-air interface, forming a dense monomolecular water-transporting layer on the material surface. This reduces the surface energy, increases the contact angle from 60° to 110°, and prevents penetration. Zn in nano-zinc oxide... 2+ The slow release of ions disrupts the cell membrane structure of molds / bacteria and inhibits their enzyme activity, achieving long-lasting and broad-spectrum antibacterial and antifungal effects. Zinc oxide can effectively absorb ultraviolet rays from sunlight and convert them into heat energy, protecting the internal epoxy / polyurethane resin molecular chains from degradation by ultraviolet light and preventing yellowing, chalking, and strength reduction of the material. The surface of nano zinc oxide particles has catalytic activity, playing a heterogeneous catalytic role in the curing reaction and reducing the reaction activation energy.

[0015] Preferably, the curing agent is one or both of ethylenediamine or isocyanate; the solvent is one or both of acetone or ethyl acetate.

[0016] The curing agent initiates and participates in the curing reaction of the resin, transforming linear or oligomeric macromolecules into a three-dimensional network solid. The two primary amine groups on the ethylenediamine molecule contain four active hydrogens, each of which can open an epoxy group to undergo an addition polymerization reaction, thereby achieving cross-linking and curing of the epoxy resin. Isocyanates contain highly active -NCO groups, which react with compounds containing active hydrogens to form a polyurethane network.

[0017] Acetone and ethyl acetate can fully dissolve the resin, reducing the viscosity of the entire system to a low level suitable for high-pressure spraying, thus improving the deep penetration efficiency of the material. Both have moderate volatility, and when combined, they balance the drying speed and completely evaporate during the curing process, reducing product residue and meeting environmental protection requirements.

[0018] This invention discloses a particleboard substrate, which is prepared by spraying the modified polymer sealing material onto the edge surface of a particleboard and then curing and polishing it.

[0019] Preferably, the surface roughness of the particleboard substrate is 3.2-6.3 μm, and the moisture content at the board edge is 8%-12%.

[0020] Surface pretreatment and sanding remove the compacted wood fibers and adhesive layers formed during the cutting process, exposing the porous and fresh wood structure. The roughness of 3.2-6.3μm provides a large number of capillary channels and micro-pits for the liquid sealing material, which facilitates the material's penetration under high pressure, while avoiding cracks caused by excessive roughness, which would make it difficult for the material to be completely filled. Amine curing agents react readily with water, and excessive moisture consumes the curing agent, resulting in incomplete curing, soft resin, and low strength. Isocyanates react with water preferentially compared to alcohols to generate carbon dioxide and urea bonds. Carbon dioxide forms bubbles in the adhesive layer, and urea bonds reduce the material's toughness. Excessive moisture content generates huge shrinkage stress on the cured sealing layer, which can easily lead to cracking or delamination.

[0021] This invention discloses a method for preparing a particleboard substrate, comprising the following steps: S1. Add the matrix resin, modified filler, toughening agent, and moisture-proofing agent to the mixing tank according to the weight parts, and stir for 15-20 minutes at a speed of 500-800 r / min and a temperature of 25-30℃; add the curing agent and solvent, reduce the speed to 300-500 r / min and continue stirring for 5-8 minutes, and adjust the viscosity of the material to 1500-2000 mPa·s. S2: Use a high-pressure spray gun to spray the material onto the edge surface of the board. After spraying, let it stand for 5-10 minutes before spraying a second time. S3. Place the coated particleboard substrate into a curing chamber with humidity below 50% for segmented curing, allow it to cool naturally to room temperature, sand the surface of the sealed layer with 240-320 grit sandpaper at a speed of 1.5-2 m / min, blow away dust with compressed air, and then conduct testing.

[0022] Preferably, in step S2, the high-pressure spray gun nozzle has a diameter of 1.5-2.0 mm, a pressure of 0.8-1.0 MPa, and a distance of 15-20 cm for spraying; the material coating thickness is 0.8-1.2 mm, and the penetration depth is greater than 0.5 mm.

[0023] High-pressure spray guns with nozzle diameters of 1.5-2.0mm, pressures of 0.8-1.0MPa, and distances of 15-20cm are used for spraying to ensure high-speed material jets, overcome surface tension barriers, achieve uniform coverage, and penetrate to a depth greater than 0.5mm.

[0024] Preferably, the specific steps of the segmented curing in step S3 are as follows: segmented curing at a heating rate of 5-10℃ / min: the first stage is cured at 40-50℃ for 1-2 hours, and the second stage is cured at 60-70℃ for 3-4 hours.

[0025] Solvents acetone and ethyl acetate have low boiling points. Rapid heating causes the solvents inside the board and coating to vaporize rapidly, generating a large number of bubbles and causing defects such as blistering and unevenness on the board surface. At the same time, rapid heating exacerbates the cross-linking reaction of epoxy and polyurethane, leading to local overheating and uneven reaction. The first stage is low-temperature curing, with the temperature slightly below the boiling point of the solvent, which gently evaporates most of the residual solvent and initiates the pre-gel point reaction of the epoxy and polyurethane system, initially transforming the viscous liquid into a non-flowing elastic gel state and forming a cross-linked network. The second stage is medium-temperature curing, which carries out the epoxy and polyurethane amine curing reaction. The epoxy, isocyanate, hydroxyl, and amine groups have high activity, which increases the cross-linking density of the material, improves the interpenetrating network structure, and enhances the material performance.

[0026] The beneficial effects of this invention are as follows: (1) Each step works together to ensure that the sealing layer is tightly bonded to the edge of the board. In the pretreatment stage, the pores are opened by grinding and the moisture content is controlled to avoid solidification bubbles. The stirring parameters are controlled during material preparation to ensure uniform dispersion. Coating and penetration ensure that the pores are fully filled. Segmented curing takes into account both shaping and cross-linking effects. Post-treatment and testing ensure dimensional accuracy and performance meet the standards. (2) This invention has excellent moisture resistance, high bonding strength, strong weather resistance and environmental protection. It can be customized according to specific scenarios and is suitable for damp scenarios such as furniture manufacturing and interior decoration. It has industrial promotion value. Detailed Implementation

[0027] Example 1:

[0028] This embodiment provides a modified polymer sealing material, specifically comprising the following components in parts by mass: 50 parts of matrix resin, 25 parts of modified filler, 8 parts of toughening agent, 5 parts of curing agent, 3 parts of moisture-proofing agent, and 8 parts of solvent; The matrix resin is a mixture of epoxy resin E-44 and polyurethane resin in a mass ratio of 1:1, with 25 parts of epoxy resin E-44 and 25 parts of polyurethane resin. The modified filler consists of 15 parts modified nano-silica and 10 parts modified mica powder. The toughening agent is a mixture of dioctyl phthalate and polyether polyol in a mass ratio of 1:1, with 4 parts of dioctyl phthalate and 4 parts of polyether polyol. The curing agent is 3 parts ethylenediamine and 2 parts isocyanate; The moisture-proofing agent is a mixture of organosilicon waterproofing agent and nano zinc oxide in a mass ratio of 2:1, with 2 parts of organosilicon waterproofing agent and 1 part of nano zinc oxide; The solvent is a mixture of acetone and ethyl acetate in a volume ratio of 1:1.

[0029] This embodiment also provides a method for preparing a particleboard substrate, which specifically includes the following steps: S1, add the matrix resin, modified filler, toughening agent, and moisture-proofing agent to the mixing tank according to the weight parts, and stir for 18 minutes at 700 r / min and 28℃; add the curing agent and solvent, reduce the speed to 350 r / min and continue stirring for 6 minutes, and adjust the material viscosity to 1800 mPa·s; S2 uses 18mm thick ordinary particleboard, sanded with 150-grit sandpaper to Ra=4.2μm, dusted with 0.5MPa, dried at 70℃ for 2.5h until the moisture content is 10%, and sprayed onto the pre-treated and sanded board edge surface with a thickness of 1.0mm using a high-pressure spray gun with a nozzle of 1.8mm and a pressure of 0.9MPa. After spraying, it is left to stand for 8 minutes to allow 0.6mm of penetration, and then a second spray is performed. S3. Place the coated particleboard substrate into a curing chamber with 45% humidity, heat it to 45℃ at 5℃ / min and cure for 1.5h, then heat it to 65℃ at 8℃ / min and cure for 3.5h. Allow it to cool naturally to room temperature, sand the surface of the sealed layer with 320-grit sandpaper at a speed of 2m / min, blow away the dust with compressed air, and then conduct testing. Example 2:

[0030] This embodiment provides a modified polymer sealing material, specifically comprising the following components in parts by mass: 50 parts of matrix resin, 30 parts of modified filler, 10 parts of toughening agent, 6 parts of curing agent, 5 parts of moisture-proofing agent, and 10 parts of solvent; The matrix resin is a mixture of epoxy resin E-44 and polyurethane resin in a mass ratio of 1:1.5, wherein the epoxy resin E-44 comprises 20 parts and the polyurethane resin comprises 30 parts. The modified filler consists of 20 parts of modified nano-silica and 10 parts of modified mica powder. The toughening agent is a mixture of dioctyl phthalate and polyether polyol in a mass ratio of 1:1, with 5 parts of dioctyl phthalate and 5 parts of polyether polyol. The curing agent is 2 parts ethylenediamine and 4 parts isocyanate; The moisture-proofing agent is a mixture of organosilicon waterproofing agent and nano zinc oxide in a mass ratio of 1.5:1, with 3 parts of organosilicon waterproofing agent and 2 parts of nano zinc oxide; The solvent is a mixture of acetone and ethyl acetate in a volume ratio of 1:1.

[0031] This embodiment also provides a method for preparing a particleboard substrate, which specifically includes the following steps: S1, add the matrix resin, modified filler, toughening agent, and moisture-proofing agent to the mixing tank according to the weight parts, and stir for 18 minutes at 700 r / min and 28℃; add the curing agent and solvent, reduce the speed to 350 r / min and continue stirring for 6 minutes, and adjust the material viscosity to 2000 mPa·s; S2 uses 25mm thick ordinary particleboard, sanded with 180-grit sandpaper to Ra=3.5μm, blown with 0.6MPa dust, dried at 80℃ for 3 hours to a moisture content of 8%, and sprayed onto the pre-treated and sanded board edge surface with a thickness of 1.2mm using a 2.0mm nozzle and 1.0MPa high-pressure spray gun. After spraying, it is left to stand for 10 minutes to allow 0.6mm of penetration, and then a second spray is performed. S3. Place the coated particleboard substrate into a curing chamber with 40% humidity, heat to 50℃ at 4℃ / min and cure for 2 hours, then heat to 70℃ at 6℃ / min and cure for 4 hours. Allow it to cool naturally to room temperature, sand the surface of the sealed layer with 280-grit sandpaper at a speed of 2m / min, blow away dust with compressed air, and then perform testing. Example 3:

[0032] This embodiment provides a modified polymer sealing material, specifically comprising the following components in parts by mass: 50 parts of matrix resin, 20 parts of modified filler, 5 parts of toughening agent, 3 parts of curing agent, 2 parts of moisture-proofing agent, and 5 parts of solvent; The matrix resin is a mixture of epoxy resin E-44 and polyurethane resin in a mass ratio of 1:1, with 25 parts of epoxy resin E-44 and 25 parts of polyurethane resin. The modified filler consists of 10 parts of modified nano-silica and 10 parts of modified mica powder. The toughening agent is a mixture of dioctyl phthalate and polyether polyol in a mass ratio of 1:1, with 2.5 parts of dioctyl phthalate and 2.5 parts of polyether polyol. The curing agent is 2 parts ethylenediamine and 4 parts isocyanate; The moisture-proofing agent is a mixture of organosilicon waterproofing agent and nano zinc oxide in a mass ratio of 1:1, with 1 part of organosilicon waterproofing agent and 1 part of nano zinc oxide. The solvent is a mixture of acetone and ethyl acetate in a volume ratio of 1:1.

[0033] This embodiment also provides a method for preparing a particleboard substrate, which specifically includes the following steps: S1, add the matrix resin, modified filler, toughening agent, and moisture-proofing agent to the mixing tank according to the weight parts, and stir for 15 minutes at 500 r / min and 28℃; add the curing agent and solvent, reduce the speed to 300 r / min and continue stirring for 5 minutes, and adjust the material viscosity to 1500 mPa·s; S2 uses 15mm thick ordinary particleboard, sanded with 120-grit sandpaper to Ra=3.2μm, blown with 0.4MPa dust, dried at 60℃ for 2 hours to a moisture content of 12%, and sprayed onto the pre-treated and sanded board edge surface with a thickness of 0.8mm using a 1.5mm nozzle and 0.8MPa high-pressure spray gun. After spraying, it is left to stand for 10 minutes to allow 0.5mm of penetration, and then a second spray is performed. S3. Place the coated particleboard substrate into a curing chamber with 40% humidity, heat to 50℃ at 4℃ / min and cure for 2 hours, then heat to 70℃ at 6℃ / min and cure for 4 hours. Allow it to cool naturally to room temperature, sand the surface of the sealed layer with 280-grit sandpaper at a speed of 2m / min, blow away dust with compressed air, and then perform testing. Example 4:

[0034] This embodiment provides a modified polymer sealing material, specifically comprising the following components in parts by mass: 40 parts of matrix resin, 25 parts of modified filler, 8 parts of toughening agent, 5 parts of curing agent, 3 parts of moisture-proofing agent, and 8 parts of solvent; The matrix resin is a mixture of epoxy resin E-44 and polyurethane resin in a mass ratio of 1:1, with 20 parts of epoxy resin E-44 and 20 parts of polyurethane resin. The modified filler consists of 15 parts modified nano-silica and 10 parts modified mica powder. The toughening agent is a mixture of dioctyl phthalate and polyether polyol in a mass ratio of 1:1, with 4 parts of dioctyl phthalate and 4 parts of polyether polyol. The curing agent is 3 parts ethylenediamine and 2 parts isocyanate; The moisture-proofing agent is a mixture of organosilicon waterproofing agent and nano zinc oxide in a mass ratio of 2:1, with 2 parts of organosilicon waterproofing agent and 1 part of nano zinc oxide; The solvent is a mixture of acetone and ethyl acetate in a volume ratio of 1:1.

[0035] This embodiment also provides a method for preparing a particleboard substrate, which specifically includes the following steps: S1, add the matrix resin, modified filler, toughening agent, and moisture-proofing agent to the mixing tank according to the weight parts, and stir for 18 minutes at 700 r / min and 28℃; add the curing agent and solvent, reduce the speed to 350 r / min and continue stirring for 6 minutes, and adjust the material viscosity to 1800 mPa·s; S2 uses 18mm thick ordinary particleboard, sanded with 150-grit sandpaper to Ra=4.2μm, dusted with 0.5MPa, dried at 70℃ for 2.5h until the moisture content is 10%, and sprayed onto the pre-treated and sanded board edge surface with a thickness of 1.0mm using a high-pressure spray gun with a nozzle of 1.8mm and a pressure of 0.9MPa. After spraying, it is left to stand for 8 minutes to allow 0.6mm of penetration, and then a second spray is performed. S3. Place the coated particleboard substrate into a curing chamber with 45% humidity, heat it to 45℃ at 5℃ / min and cure for 1.5h, then heat it to 65℃ at 8℃ / min and cure for 3.5h. Allow it to cool naturally to room temperature, sand the surface of the sealed layer with 320-grit sandpaper at a speed of 2m / min, blow away the dust with compressed air, and then conduct testing. Example 5:

[0036] This embodiment provides a modified polymer sealing material, specifically comprising the following components in parts by mass: The matrix resin consists of 60 parts, modified filler of 25 parts, toughening agent of 8 parts, curing agent of 5 parts, moisture-proofing agent of 3 parts, and solvent of 8 parts. The matrix resin is a mixture of epoxy resin E-44 and polyurethane resin in a mass ratio of 1:1, with 30 parts of epoxy resin E-44 and 30 parts of polyurethane resin. The modified filler consists of 15 parts modified nano-silica and 10 parts modified mica powder. The toughening agent is a mixture of dioctyl phthalate and polyether polyol in a mass ratio of 1:1, with 4 parts of dioctyl phthalate and 4 parts of polyether polyol. The curing agent is 3 parts ethylenediamine and 2 parts isocyanate; The moisture-proofing agent is a mixture of organosilicon waterproofing agent and nano zinc oxide in a mass ratio of 2:1, with 2 parts of organosilicon waterproofing agent and 1 part of nano zinc oxide; The solvent is a mixture of acetone and ethyl acetate in a volume ratio of 1:1.

[0037] This embodiment also provides a method for preparing a particleboard substrate, which specifically includes the following steps: S1, add the matrix resin, modified filler, toughening agent, and moisture-proofing agent to the mixing tank according to the weight parts, and stir for 18 minutes at 700 r / min and 28℃; add the curing agent and solvent, reduce the speed to 350 r / min and continue stirring for 6 minutes, and adjust the material viscosity to 1800 mPa·s; S2 uses 18mm thick ordinary particleboard, sanded with 150-grit sandpaper to Ra=4.2μm, dusted with 0.5MPa, dried at 70℃ for 2.5h until the moisture content is 10%, and sprayed onto the pre-treated and sanded board edge surface with a thickness of 1.0mm using a high-pressure spray gun with a nozzle of 1.8mm and a pressure of 0.9MPa. After spraying, it is left to stand for 8 minutes to allow 0.6mm of penetration, and then a second spray is performed. S3. Place the coated particleboard substrate into a curing chamber with 45% humidity, heat it to 45℃ at 5℃ / min and cure for 1.5h, then heat it to 65℃ at 8℃ / min and cure for 3.5h. Allow it to cool naturally to room temperature, sand the surface of the sealed layer with 320-grit sandpaper at a speed of 2m / min, blow away the dust with compressed air, and then conduct testing.

[0038] Comparative Example 1: This comparative example provides a moisture-proof solution for traditional PVC edge banding strips, specifically comprising the following components: 1.5mm thick commercially available ordinary PVC edge banding, EVA hot melt adhesive; The ordinary PVC edge banding strip is unmodified and has a density of 1.35 g / cm³. 3 Temperature resistance range: -10℃ to 60℃; The EVA hot melt adhesive has a solid content of 60%, a melting point of 90-110℃, and a viscosity of 2500mPa·s / 180℃.

[0039] This comparative example also provides a traditional method for preparing a particleboard substrate, which specifically includes the following steps: S1, take an 18mm thick ordinary particleboard, cross-sand it with 150-grit sandpaper until Ra=4.2μm, blow it with 0.5MPa compressed air, and dry it at 70℃ for 2.5h until the moisture content is 10%; S2, using a manual edge banding machine, heats the EVA hot melt adhesive to 180℃ to melt it, and then evenly applies it to the edge of the particleboard, with an adhesive application rate of 120g / m². 2 Immediately attach the PVC edge banding strip, compact it with a pressure roller at 0.6MPa and a speed of 1.5m / min, and allow it to cool naturally at room temperature for 30 minutes. S3, use 240-grit sandpaper to manually remove excess burrs from the edge banding strip.

[0040] Comparative Example 2: This comparative example provides a common alkyd resin moisture-proof paint application solution, specifically comprising the following components: Commercially available ordinary alkyd resin moisture-proof paint, turpentine; The alkyd resin moisture-proof paint has a solid content of 45%, and its main components are alkyd resin and titanium dioxide, without any penetrating additives. The turpentine oil has a VOC content >95%.

[0041] This comparative example also provides a traditional method for preparing a particleboard substrate, which specifically includes the following steps: S1, take an 18mm thick ordinary particleboard, cross-sand it with 150-grit sandpaper until Ra=4.2μm, blow it with 0.5MPa compressed air, and dry it at 70℃ for 2.5h until the moisture content is 10%; S2, mix moisture-proof paint and turpentine in a mass ratio of 4:1, stir at room temperature for 5 minutes until the viscosity is 1200 mPa·s, apply two coats by hand with a wool brush, the first coat has a dry film thickness of 0.3 mm, dry at room temperature of 25℃ and humidity of 60% for 2 hours, then apply the second coat, the total dry film thickness is 0.6 mm; after the coating is completed, cure at room temperature for 24 hours. S3, remove surface dust.

[0042] Comparative Example 3: This comparative example provides a sealing solution using an unmodified polymer material, specifically comprising the following components: Commercially available ordinary alkyd resin moisture-proof paint, turpentine; The alkyd resin moisture-proof paint has a solid content of 45%, and its main components are alkyd resin and titanium dioxide, without any penetrating additives. The turpentine oil has a VOC content >95%.

[0043] This embodiment also provides a traditional method for preparing a particleboard substrate, which specifically includes the following steps: S1, take an 18mm thick ordinary particleboard, cross-sand it with 150-grit sandpaper until Ra=4.2μm, blow it with 0.5MPa compressed air, and dry it at 70℃ for 2.5h until the moisture content is 10%; S2, mix moisture-proof paint and turpentine in a mass ratio of 4:1, stir at room temperature for 5 minutes until the viscosity is 1200 mPa·s, apply two coats by hand with a wool brush, the first coat has a dry film thickness of 0.3 mm, dry at room temperature of 25℃ and humidity of 60% for 2 hours, then apply the second coat, the total dry film thickness is 0.6 mm; after the coating is completed, cure at room temperature for 24 hours. S3, remove surface dust.

[0044] Test Example 1: This test example is for the performance testing of particleboard substrates prepared in Examples 1-5 and Comparative Examples 1-3. The specific results are shown in Table 1. Example 1: Adhesion grade 1, 24-hour expansion rate 1.2%, temperature cycling cracking rate 0.5%, VOCs 95 g / L: Balanced performance; epoxy resin E-44 and polyurethane resin are compounded in a 1:1 ratio to form an interpenetrating network, balancing rigid and flexible segments; modified nano-silica and mica powder are bridged by KH-550 to form a strong three-dimensional network with resin and wood; combined with 0.9MPa high-pressure penetration, grade 1 adhesion is achieved; organosilicon waterproofing agent forms a highly efficient hydrophobic film on the surface, with deep penetration extending the penetration path; polyurethane has good water resistance; the three work synergistically to reduce the expansion rate; polyether polyol chemical bonding toughens the substrate; nano-zinc oxide resists UV aging; segmented curing in the substrate preparation process fully crosslinks the materials, improving their performance; the acetone / ethyl acetate compound solvent itself has low VOCs and is fully driven away and volatilized during segmented curing, leaving little residue.

[0045] Example 2: Adhesion grade 0, expansion rate 1.0%, cracking rate 0.3%, VOCs 90g / L: The proportion of polyurethane was increased, the modified filler was increased to 30 parts, and the moisture-proofing agent was increased to 5 parts, resulting in stronger toughness and deformation ability; the physical barrier was more complete, the three-dimensional reinforcing network was denser, and the moisture resistance and crack resistance were improved; the spraying pressure was increased to 1.0MPa, the penetration rate was higher, and the curing temperature was increased to 70℃, which is conducive to achieving a higher degree of crosslinking.

[0046] Example 3: Adhesion grade 1, expansion rate 2.4%, cracking rate 1.0%, VOCs 130g / L: The functional component mass fraction is low, the solvent is insufficient to completely solubilize the resin and filler, it cannot become a low viscosity solution, the mixing is uneven, there are agglomerates, and the resin molecular chains are not fully extended, and the chain segment cross-linking reaction is incomplete.

[0047] Examples 4 and 5: Reduced adhesion, deteriorated moisture resistance and weather resistance, and excessive VOCs: Example 4: The low resin content resulted in an excessively thin resin layer on the surface of fillers and other particles, weak interfacial bonding, and insufficient resin coating, leading to decreased adhesion. Microscopic defects may exist inside the cured material, resulting in decreased moisture resistance and weather resistance, and small molecules are more likely to remain, increasing VOCs. Example 5: The high resin content resulted in incomplete curing, with a large number of unreacted linear molecular chains, reduced material strength and heat resistance, and increased susceptibility to cracking during temperature cycling. The incompletely cross-linked network encapsulated more solvent molecules, resulting in the highest VOC content. The high resin content also led to greater curing shrinkage, generating greater internal stress and weakening adhesion.

[0048] Comparative Example 1: Adhesion grade 3, expansion rate 8.5%, cracking rate 25%, VOCs 150g / L: Relies on the physical adhesion of EVA hot melt adhesive, with no chemical bond to the wood. The interface is fragile and easily delaminated due to humidity and heat, resulting in poor adhesion; only physical edge sealing is used, without sealing the pores on the board edges, allowing moisture to penetrate from the inside of the edge sealing strip or micro-gap; the large difference in thermal expansion coefficients between PVC and the board makes it prone to gaps after temperature cycling, accelerating water ingress and resulting in poor moisture resistance; under drastic temperature changes, both EVA adhesive and PVC age, become brittle, and shrink, leading to delamination and edge curling; EVA hot melt adhesive itself contains small molecule substances, which are released during high-temperature construction, resulting in high VOC content.

[0049] Comparative Example 2: Adhesion grade 2, expansion rate 6.2%, cracking rate 18%, VOCs 350g / L: Alkyd paint forms a film on the edge surface of the board, which cannot penetrate. It relies solely on the physical bonding between the paint film and the sanded wood, without chemical bonds or deep anchoring, resulting in an unstable adhesion grade 2. The thin paint film is prone to micro-cracks, allowing moisture to easily penetrate. The different expansion coefficients of the paint film and the substrate make it easy to peel off from the interface after temperature and humidity cycles, leading to a high expansion rate. Turpentine, a high-VOC, low-solids oil, is used as a diluent, resulting in a large amount of solvent evaporating into the air and exceeding the standard.

[0050] Comparative Example 3: Adhesion grade 2, expansion rate 4.1%, cracking rate 12%, VOCs 320g / L: The filler was not treated with KH-550, and it was easy to agglomerate in the resin. It could not form a three-dimensional connection and was just a regular filler. It was applied by brushing and cured at room temperature, which could not achieve high pressure penetration and full cross-linking. It lacked the core features of the example and its performance dropped sharply.

[0051] In summary, this invention constructs an interpenetrating network using a compound of epoxy-polyurethane resins, achieves a three-dimensional chemical bridge between the resin, filler, and wood by utilizing fillers modified with silane coupling agents, and combines the synergistic effects of toughening agents and moisture-proofing agents with high-pressure penetration spraying and segmented curing processes to form a deeply anchored, dense composite material layer on the edge of particleboard. Experimental data fully demonstrate that Examples 1 and 2 exhibit superior performance in terms of adhesion, moisture resistance, durability, and environmental friendliness, significantly outperforming traditional physical edge sealing, surface coating, and unmodified simplified solutions.

Claims

1. A modified polymer sealing material, characterized in that, The sealing material comprises the following components in parts by weight: 40-60 parts of matrix resin, 20-30 parts of modified filler, 5-10 parts of toughening agent, 3-6 parts of curing agent, 2-5 parts of moisture-proofing agent, and 5-10 parts of solvent; the matrix resin is a mixture of epoxy resin E-44 and polyurethane resin in a mass ratio of 1:(1-1.5).

2. The modified polymer sealing material according to claim 1, characterized in that, The sealing material comprises the following components in parts by weight: 45-55 parts of matrix resin, 25-30 parts of modified filler, 8-10 parts of toughening agent, 5-6 parts of curing agent, 3-5 parts of moisture-proofing agent, and 8-10 parts of solvent; the matrix resin is a mixture of epoxy resin E-44 and polyurethane resin in a mass ratio of 1:(1-1.5).

3. The modified polymer sealing material according to claim 1 or 2, characterized in that, The modified filler is one or both of nano-silica and mica powder modified with a silane coupling agent; the silane coupling agent is KH-550.

4. The modified polymer sealing material according to claim 1 or 2, characterized in that, The toughening agent is a compound of dioctyl phthalate and polyether polyol in a mass ratio of 1:(1-1.5); the moisture-proofing agent is a compound of organosilicon waterproofing agent and nano zinc oxide in a mass ratio of (1-2):

1.

5. The modified polymer sealing material according to claim 1 or 2, characterized in that, The curing agent is one or both of ethylenediamine or isocyanate; the solvent is one or both of acetone or ethyl acetate.

6. A particleboard substrate, characterized in that, Based on the modified polymer sealing material according to any one of claims 1-5, the modified polymer sealing material is sprayed onto the edge surface of a particleboard and then cured and polished to prepare a particleboard substrate.

7. The particleboard substrate according to claim 6, characterized in that, The particleboard substrate has a surface roughness of 3.2-6.3 μm and a moisture content of 8%-12% at the board edge.

8. A method for preparing a particleboard substrate according to any one of claims 6-7, characterized in that, Includes the following steps: S1. Add the matrix resin, modified filler, toughening agent, and moisture-proofing agent to the mixing tank according to the weight parts, and stir for 15-20 minutes at a speed of 500-800 r / min and a temperature of 25-30℃; add the curing agent and solvent, reduce the speed to 300-500 r / min and continue stirring for 5-8 minutes, and adjust the viscosity of the material to 1500-2000 mPa・s; S2: Use a high-pressure spray gun to spray the material onto the pre-treated and sanded board edge surface. After spraying, let it stand for 5-10 minutes before spraying a second time. S3. Place the coated particleboard substrate into a curing chamber with humidity below 50% for segmented curing, allow it to cool naturally to room temperature, sand the surface of the sealed layer with 240-320 grit sandpaper at a speed of 1.5-2 m / min, blow away dust with compressed air, and then conduct testing.

9. The method for preparing a particleboard substrate according to claim 8, characterized in that, In step S2, the high-pressure spray gun nozzle diameter is 1.5-2.0mm, the pressure is 0.8-1.0MPa, and the distance is 15-20cm for spraying; the material spraying thickness is 0.8-1.2mm, and the penetration depth is greater than 0.5mm.

10. The method for preparing a particleboard substrate according to claim 8, characterized in that, The specific steps of the segmented curing in step S3 are as follows: segmented curing at a heating rate of 4-10℃ / min: the first stage is cured at 40-50℃ for 1-2 hours, and the second stage is cured at 60-70℃ for 3-4 hours.

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