Preparation method of flame-retardant artificial board composite facing material

Abstract

The invention discloses a preparation method of a flame-retardant artificial board composite facing material, and belongs to the technical field of artificial board facing. According to the method, a multi-stage flame-retardant protection structure is formed by constructing a physical barrier layer of a silicon-based flame-retardant fiber skeleton and combining chemical flame-retardant modification of a resin matrix. The preparation process comprises the following steps: preparing a silicon flame retardant into the fiber base layer by adopting a tank furnace wire drawing process, and performing high-temperature treatment and siloxane activation to obtain the activated flame-retardant base layer; melamine formaldehyde resin and a silicon flame retardant are compounded to prepare a flame-retardant modified adhesive; the activated flame-retardant base layer is soaked in a modified adhesive and then dried to be semi-cured to serve as a reinforcing layer, then the printing paper is soaked in melamine formaldehyde resin and then dried to be semi-cured to serve as a facing layer, and finally the activated flame-retardant base layer and the facing layer are assembled to be subjected to pre-hot pressing forming. The interlayer bonding force is enhanced through interface activation treatment, the compatibility of a flame retardant and a resin matrix is improved, and the obtained composite material has excellent flame retardance (capable of reaching the B1 level), high bonding strength and good toughness and is suitable for the fields of indoor decoration and furniture manufacturing with high fireproof safety requirements.

Description

Technical Field

[0001] This invention relates to a method for preparing a flame-retardant composite engineered wood panel surface material, and more particularly to a method for preparing a flame-retardant wood-based engineered wood panel composite surface material that can be rapidly hot-pressed and bonded. Technical Background Engineered wood products, as a fundamental material in interior decoration, furniture manufacturing, and building decoration, are widely used due to their high resource utilization rate, good dimensional stability, and ease of processing. However, engineered wood products and their surface materials are mainly composed of wood fibers or organic polymers, and their inherent flammability has become a key bottleneck restricting their application in high-rise buildings, public places, and other areas with strict fire safety requirements. In the event of a fire, these materials will not only burn rapidly, promoting the spread of fire, but will also release large amounts of dense smoke and toxic gases, seriously threatening personnel evacuation and fire rescue. Therefore, the development of engineered wood composite surface materials that combine excellent flame retardant properties with good physical and mechanical properties is of great significance for improving the overall fire safety level of interior decoration.

[0002] In existing technologies, the main approaches to improving the flame retardant properties of engineered wood panel finishes are surface coating with flame-retardant paint or direct addition of flame retardants to the resin matrix. However, these methods have significant limitations in practical applications. On the one hand, traditional surface-coated flame-retardant layers are prone to wear and peeling during long-term use, and their adhesion to the substrate is limited, making it difficult to provide durable flame retardant protection. On the other hand, while directly adding flame retardants to impregnating resins or adhesives is simple, a high dosage is often required to ensure the flame retardant effect. This not only significantly reduces the resin's fluidity and wettability to paper or substrates but also easily leads to the deterioration of the mechanical properties of the finish, such as decreased toughness and reduced adhesive strength, thus affecting the surface decoration quality and service life of the engineered wood panel. Furthermore, existing technologies mostly employ a single flame retardant mechanism, making it difficult to form an efficient and stable physical thermal insulation barrier on the material surface. This results in rapid pyrolysis of the material interior under high-temperature flame impact, and the flame retardant efficiency still needs improvement.

[0003] Inorganic silicon-based flame retardants exhibit unique advantages in the flame retardant field due to their low toxicity, low smoke, good thermal stability, and ability to form a dense silicate protective layer. However, when applied directly in powder form to engineered wood panel veneer systems, they generally suffer from poor dispersibility and incompatible compatibility with organic resin matrices, easily forming defects at the interface, which become stress concentration points and weaken the overall strength and toughness of the material. How to organically combine the highly efficient flame-retardant properties of silicon-based flame retardants with the good mechanical properties and decorative effects required for engineered wood panel veneer materials is a pressing technical challenge that needs to be addressed in this field.

[0004] In response to the current situation where existing engineered wood panel veneer materials struggle to balance flame retardancy, toughness, and adhesive strength, this invention constructs a physical barrier layer with a silicon-based flame-retardant fiber material as its framework, combined with chemical flame-retardant modification of the resin matrix, to achieve multi-level flame-retardant protection. Simultaneously, it utilizes interface activation technology to enhance the bonding force between the various structural layers, thereby fundamentally improving the overall performance of flame-retardant engineered wood panel composite veneer materials and meeting increasingly stringent fire safety standards and high-end application requirements. Summary of the Invention

[0005] To address the problems of insufficient flame retardancy, poor toughness, and low bonding strength in existing engineered wood panel finishes, this invention develops a novel flame-retardant composite finish material for engineered wood panels, thereby improving the flame retardancy and strength of these finishes and further enhancing the safety performance of engineered wood panels. A method for preparing this flame-retardant composite finish material mainly includes the following steps: (1) Preparation and activation of the barrier layer: The silicon flame retardant is spun and woven by the pool furnace drawing process to obtain the flame retardant base layer, which is then subjected to high temperature treatment and activated by siloxane to finally obtain the activated flame retardant base layer. (2) Flame retardant modification of adhesives: using melamine-formaldehyde resin as a pre-cured adhesive, flame retardant pre-cured adhesives are obtained by adding silicone flame retardants. (3) Preparation of composite decorative material: First, the activated flame-retardant barrier layer prepared in (1) is impregnated with the flame-retardant modified adhesive prepared in (2) and dried to a semi-cured state to obtain a reinforced flame-retardant barrier layer; then, the printing paper is impregnated with melamine-formaldehyde resin and dried to a semi-cured state to obtain a decorative semi-cured layer; then, the decorative layer semi-cured sheet and the reinforcing layer semi-cured sheet are sequentially assembled and fed into a hot press for preheating and pressing in the order from bottom to top or from top to bottom to obtain a flame-retardant artificial board composite decorative material.

[0006] Preferably, in step (1), the silicon-based flame retardant is one or more of SiO2, talc, aluminum silicate, pyrophyllite powder, basalt powder, and glass powder. Preferably, in step (1), the thickness of the flame-retardant base layer is controlled between 0.03 mm and 0.50 mm; Preferably, in step (1), the siloxane is mainly one or more of isocyanate-based silane, N-β-(aminoethyl)-γ-aminopropyltrimeth(eth)oxysilane, γ-aminopropyltriethoxysilane, 3-ureopropyltriethoxysilane, and 3-isocyanate-based propyltriethoxysilane. Preferably, in step (1), the silane coupling agent is prepared into a 0.5-2% alcohol-water solution, wherein the volume ratio of alcohol to water is 4:1, and after stirring evenly, it is allowed to stand for hydrolysis for 30-90 min. Preferably, in step (1), the high-temperature treatment temperature is controlled between 150 and 450 ℃, and the treatment time is between 10 and 1000 s; Preferably, in step (1), the flame-retardant base layer treated at high temperature is immersed in the above-mentioned treatment liquid for 3-5 minutes to ensure full immersion. Preferably, in step (1), the impregnated flame-retardant base layer is dried at 105-120℃ for 15-20 min to allow the silane to undergo a polycondensation reaction with the glass fiber surface; Preferably, in step (2), the solid content of melamine-formaldehyde resin is controlled at 40%~70%; Preferably, in step (2), the silicon-based flame retardant is one or more of SiO2, talc, aluminum silicate, pyrophyllite powder, basalt powder, and glass powder. Preferably, in step (2), the amount of silicon-based flame retardant added is 10-15% of the solid content of melamine-formaldehyde resin, and the mixture is stirred and mixed at 40-50 °C for 30-60 min to obtain flame-retardant modified melamine-formaldehyde resin. Preferably, in step (3), the amount of resin impregnated in the flame-retardant barrier layer is controlled at 60%~150%, the drying temperature is controlled at 100~140℃, and the drying time is 5~30s; Preferably, in step (3), the amount of resin impregnated with the printing paper is controlled at 80%~150%, the drying temperature is controlled at 100~140℃, and the drying time is 5~60s; Preferably, in step (3), the preheating temperature is 100~140 ℃, the hot pressing pressure is 0.5-1.0 MPa, and the hot pressing time is 5~50s; Compared with the prior art, the present invention has the following beneficial effects: 1. Significantly improved interfacial bonding strength: Pretreatment of the flame-retardant base layer with KH-550 silane coupling agent forms a chemically bonded "molecular bridge" between the flame-retardant base layer fiber surface and melamine-formaldehyde resin, which increases the interfacial bonding strength by more than 50% and significantly improves water resistance and aging resistance.

[0007] 2. Flame retardant performance meets B1 standard: The melamine-formaldehyde resin modified with silicone flame retardant has a limiting oxygen index of over 31.9%, and meets the B1 flame retardant standard requirement in vertical burning tests; at the same time, the introduction of the flame retardant base layer impregnated with silicone flame retardant modified melamine-formaldehyde resin further enhances the overall flame retardant performance.

[0008] 3. Significantly improved toughness: The introduction of silicone-based flame retardants increases the elongation at break of melamine-formaldehyde resin by 124%, effectively solving the problems of high brittleness and easy cracking of traditional melamine-formaldehyde resin, and improving the wear resistance of the finishing layer by 25%.

[0009] 4. Improved production efficiency: The addition of silicone-based flame retardants reduces the curing time of melamine-formaldehyde resin to half of the original time, thereby reducing energy consumption and improving production efficiency.

[0010] 5. Integrated Structural Design: Through the synergistic effect of the reinforcing layer and the finishing layer, the composite material possesses both high strength, high flame retardancy, and excellent decorative effect, meeting the application requirements of high-end decorative materials. Detailed Embodiments: To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0011] The specific embodiments of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0012] Example 1 Using SiO2 as raw material, a flame-retardant base layer with a thickness of 0.1 mm was produced using a tank furnace drawing process. After dewaxing by high-temperature heat treatment at 350℃, it was ready for use. A 1% KH-550 alcohol-water solution (ethanol:water = 4:1, volume ratio) was prepared, stirred evenly, and allowed to stand for hydrolysis for 60 minutes. The dewaxed flame-retardant base layer was immersed in the treatment solution for 5 minutes, then removed and dried in an oven at 110℃ for 20 minutes to obtain an activated flame-retardant base layer treated with a coupling agent. 100 parts of melamine-formaldehyde resin with a solid content of 55% were added, and 6.6 parts of SiO2 were added. The mixture was stirred and mixed at 45℃ for 45 minutes to obtain a flame-retardant modified melamine-formaldehyde resin. The activated flame-retardant base layer treated above was impregnated with the flame-retardant modified melamine-formaldehyde resin, with the impregnation amount controlled at 120%, and dried at 100℃ to a semi-cured state to obtain a reinforcing layer semi-cured sheet. The printing paper is impregnated with melamine-formaldehyde resin adhesive, with the impregnation amount controlled at 80%, and dried at 100℃ to a semi-cured state for later use. The impregnated printing paper and the activated flame-retardant base layer are then assembled sequentially and fed into a hot press. The hot pressing temperature is 110℃, the pressure is 0.5 MPa, and the hot pressing time is 10s to obtain the flame-retardant artificial board composite decorative material.

[0013] Performance testing: The limiting oxygen index was 32.5% according to GB / T 2406.3-2022; the surface bond strength was 0.52 MPa according to GB / T 17657-2013; and the immersion peel test was qualified.

[0014] Specific embodiments of the present invention have been described above. However, those skilled in the art should understand that the above embodiments are intended to illustrate the principles of the invention, and the present invention is not limited to the specific embodiments. Any technical modifications made to the present invention without departing from the technology of the present invention are within the protection scope of the present invention.

Claims

1. A method for preparing a flame-retardant engineered wood composite surface material mainly includes the following steps: (1) Preparation and activation of the barrier layer: The silicon flame retardant is spun and woven by the pool furnace drawing process to obtain the flame retardant base layer, which is then subjected to high temperature treatment and activated by siloxane to finally obtain the activated flame retardant base layer. (2) Flame retardant modification of adhesives: using melamine-formaldehyde resin as a pre-cured adhesive, flame retardant pre-cured adhesives are obtained by adding silicone flame retardants. (3) Preparation of composite decorative material: First, the activated flame-retardant barrier layer prepared in (1) is impregnated with the flame-retardant modified adhesive prepared in (2) and dried to a semi-cured state to obtain a reinforced flame-retardant barrier layer; then, the printing paper is impregnated with melamine-formaldehyde resin and dried to a semi-cured state to obtain a decorative semi-cured layer; then, the decorative layer semi-cured sheet and the reinforcing layer semi-cured sheet are sequentially assembled and fed into a hot press for preheating and pressing in the order from bottom to top or from top to bottom to obtain a flame-retardant artificial board composite decorative material.

2. Preferably, in step (1), the silicon-based flame retardant is one or more of SiO2, talc, aluminum silicate, pyrophyllite powder, basalt powder, and glass powder; Preferably, in step (1), the thickness of the flame-retardant base layer is controlled between 0.03 mm and 0.50 mm; Preferably, in step (1), the siloxane is mainly one or more of isocyanate-based silane, N-β-(aminoethyl)-γ-aminopropyltrimeth(eth)oxysilane, γ-aminopropyltriethoxysilane, 3-ureopropyltriethoxysilane, and 3-isocyanate-based propyltriethoxysilane. Preferably, in step (1), the silane coupling agent is prepared into a 0.5-2% alcohol-water solution, wherein the volume ratio of alcohol to water is 4:1, and after stirring evenly, it is allowed to stand for hydrolysis for 30-90 min. Preferably, in step (1), the high-temperature treatment temperature is controlled between 150 and 450 ℃, and the treatment time is 10 to 1000 s; Preferably, in step (1), the flame-retardant base layer treated at high temperature is immersed in the above-mentioned treatment liquid for 3-5 minutes to ensure full immersion. Preferably, in step (1), the impregnated flame-retardant base layer is dried at 105-120°C for 15-20 min to allow silane to undergo a polycondensation reaction with the glass fiber surface.

3. Preferably, in step (2), the solid content of melamine-formaldehyde resin is controlled at 40%~70%; Preferably, in step (2), the silicon-based flame retardant is one or more of SiO2, talc, aluminum silicate, pyrophyllite powder, basalt powder, and glass powder. Preferably, in step (2), the amount of silicon-based flame retardant added is 10-15% of the solid content of melamine-formaldehyde resin, and the mixture is stirred and mixed at 40-50 °C for 30-60 min to obtain flame-retardant modified melamine-formaldehyde resin.

4. Preferably, in step (3), the amount of resin impregnated in the flame-retardant barrier layer is controlled at 60%~150%, the drying temperature is controlled at 100~140℃, and the drying time is 5~30s; Preferably, in step (3), the amount of resin impregnated with the printing paper is controlled at 80%~150%, the drying temperature is controlled at 100~140℃, and the drying time is 5~60s; Preferably, in step (3), the preheating temperature is 100~140 ℃, the hot pressing pressure is 0.5-1.0 MPa, and the hot pressing time is 5~50s.