Preparation method of artificial board pre-sizing flame-retardant inorganic fiber barrier layer

Abstract

The invention provides a preparation method of a pre-sizing flame-retardant inorganic fiber barrier layer of an artificial board, which comprises the following steps of: compounding an inorganic flame retardant and a thermocuring adhesive to form a flame-retardant adhesive, weaving inorganic fibers such as alkali-free glass fibers into grey cloth, performing thermoforming, dipping in a glue solution, drying and curing, and drying to obtain the pre-sizing flame-retardant inorganic fiber barrier layer of the artificial board. The flexible barrier layer with physical barrier and chemical flame retardance is prepared, the problems that a traditional wood artificial board is inflammable and a flame retardant is prone to loss are solved, compatibility of efficient fire prevention and industrial production is achieved, and the strict flame retardant requirement in the fields of buildings and furniture is met.

Description

Technical Field

[0001] This invention relates to the preparation of flame-retardant barrier layer materials for wood-based panels used in timber-framed buildings and furniture, and particularly to a method for preparing a pre-glued flame-retardant inorganic fiber barrier layer for wood-based panels. Technical Background As a natural organic material, wood is mainly composed of cellulose, hemicellulose, and lignin. It has a low ignition point, typically between 170 and 300°C, making it easily combustible and releasing large amounts of heat and smoke when exposed to fire. Untreated wood-based panels, such as plywood, particleboard, and fiberboard, also possess this characteristic, making them highly susceptible to spreading fire. Furthermore, because these panels contain adhesives, they may release even more toxic fumes when burning.

[0002] With the promotion of green building and sustainable development concepts, modern timber-framed buildings (especially high-rise timber-framed and prefabricated timber-framed buildings) are experiencing a global resurgence. However, there is a contradiction between the flammability of wood and building fire safety codes. Most countries and regions have clear fire resistance requirements for wood materials used in building structures or interior decoration, such as China's GB 8624 "Classification of Burning Performance of Building Materials and Products", the EU's EN 13501, and the US's ASTM E84. Flame retardant treatment can delay the ignition time of wood, reduce the flame spread rate, and decrease the heat release rate, buying valuable time for evacuation and fire rescue, and preventing premature failure of structural strength. Furniture is a major ignition source and accelerant in indoor fires. Wood-based panels are widely used in panel furniture, cabinets, office furniture, etc. If not flame retardant treated, they are easily ignited by cigarette butts, electrical sparks, high-temperature electrical appliances, etc.; when burning, they release large amounts of toxic fumes (such as CO, formaldehyde, etc.), harming human health; at the same time, their combustion behavior accelerates the occurrence of "flashover," causing the entire room to quickly become engulfed in flames. Therefore, regulations often require that furniture used in public places be made of flame-retardant engineered wood.

[0003] Flame-retardant treatment of wood-based panels used in timber-framed buildings and furniture is not only a basic requirement for meeting regulatory compliance, but also a key measure to protect people's lives and property, improve the fire resistance of buildings, and promote the sustainable use of timber. In the future, the application and standardization of efficient, environmentally friendly, and economical flame-retardant technologies in wood materials should continue to be promoted. In recent years, significant progress has been made in the research of flame-retardant wood-based panels, focusing on the development of advanced processing technologies such as environmentally friendly halogen-free flame retardants (e.g., phosphorus-nitrogen synergistic systems, bio-based flame retardants), nanocomposite technology, microencapsulation, and surface functionalization. Comprehensive fire performance evaluation methods, such as cone calorimeters, are being gradually introduced to drive product development towards high efficiency, low smoke, low toxicity, and multifunctional integration. Simultaneously, green manufacturing processes and standards systems are also continuously being improved. However, the field still faces multiple challenges: (1) it is difficult to balance flame retardancy efficiency with environmental protection and mechanical properties; (2) water-soluble flame retardants are prone to migration and loss, resulting in poor durability; (3) they are not compatible with existing adhesives and production lines; (4) they are costly and have limited market acceptance; in addition, the lack of comprehensive coverage of relevant mandatory standards and the lag in supervision have restricted the promotion and application of high-quality flame-retardant artificial boards.

[0004] Fiberglass has potential as a flame-retardant layer for engineered wood products. Its inorganic, non-metallic properties endow it with non-combustibility and high-temperature stability, allowing it to act as a physical barrier to slow the spread of fire. It primarily functions as an inorganic, non-combustible physical barrier and reinforcing framework: forming a covering layer on the surface of the board, effectively isolating heat and oxygen; simultaneously, its high strength and heat resistance enhance the integrity of the flame-retardant coating or composite structure, preventing cracking and peeling. However, it typically cannot be used alone as a flame-retardant system and needs to be used in conjunction with cement-based, resin-based materials or chemical flame retardants such as aluminum hydroxide to achieve high fire protection standards. Furthermore, in practical applications, the interface bonding process and cost factors must be considered.

[0005] This invention uses glass fiber as the main barrier layer and prepares a pre-glued flame-retardant inorganic fiber barrier layer for wood-based panels with rapid and continuous production characteristics by loading a composite coating with adhesive and flame-retardant barrier properties onto its surface and pores through an impregnation process. Summary of the Invention

[0006] (1) Synthesis of flame retardant adhesive: A synergistic flame retardant system (component A) is prepared by using inorganic Si, Mg, and Al flame retardants and nitrogen-phosphorus intumescent flame retardants as flame retardant additives. It is mainly composed of one or more of silica, silica powder, magnesium hydroxide, aluminum hydroxide, boehmite, ammonium polyphosphate, guanidine phosphate, and ammonium phytate. The adhesive body (component B) is prepared by using thermosetting adhesive as the adhesive body. It is mainly composed of one or more of phenolic resin, urea-formaldehyde resin, melamine-modified phenolic resin adhesive, melamine-modified urea-formaldehyde resin, and melamine-formaldehyde resin. The flame retardant adhesive is prepared by compounding and blending components A and B.

[0007] (2) Preparation of inorganic fiber barrier layer: Inorganic fiber is used as warp and weft. After surface treatment, it is woven by a braiding machine through warping-weaving-post-treatment process to prepare an inorganic fiber barrier layer with barrier properties.

[0008] (3) Preparation of pre-applied flame-retardant inorganic fiber barrier layer: The inorganic fiber barrier layer impregnated with flame-retardant adhesive is obtained by surface cleaning-impregnation and metering-drying and curing process.

[0009] Preferably, in step (1), the mass ratio of inorganic Si, Mg, and Al flame retardants to nitrogen-phosphorus intumescent flame retardants in component A is 3:8 to 6:1.

[0010] Preferably, in step (1), the solid content of the thermosetting adhesive in component B is 1.5%~20%, and the dispersion temperature is 15℃~50℃.

[0011] Preferably, in step (1), the mass ratio of components A and B is 5:5 to 5:1, and the mixture is stirred thoroughly until it is evenly dispersed.

[0012] Preferably, in step (2), the inorganic fiber is woven from one or more composites of alkali-free glass fiber, high-strength glass fiber, basalt fiber, and ceramic fiber.

[0013] Preferably, in step (2), the woven fabric is subjected to a short-term (1-3 minutes) heat setting treatment at a temperature of 150℃~350℃ during the post-processing.

[0014] Preferably, in step (3), the fabric is preheated during surface treatment at a temperature of 80°C to 120°C.

[0015] Preferably, in step (3), the (dry adhesive mass / dry cloth mass) during the impregnation and metering process is controlled between 10% and 120%, preferably 40% to 60%.

[0016] Preferably, in step (3), the drying and curing is carried out by low-temperature drying, with the drying temperature controlled between 60℃ and 105℃ and the drying time controlled between 1 and 13 minutes, to obtain a pre-applied flame-retardant inorganic fiber barrier layer. Detailed Implementation

[0017] To better illustrate the technical means and preparation process of this invention, the invention will be described below with reference to specific implementation examples.

[0018] Example 1: (1) Using ammonium polyphosphate, magnesium oxide, aluminum hydroxide, and 10% solid melamine-modified urea-formaldehyde resin solution as the components of flame retardant adhesive synthesis, the solution is prepared in a mass ratio of 1:1:1:9 and fully dispersed to obtain a flame retardant adhesive solution; (2) Using alkali-free glass fiber as warp and weft, the solution is woven by a weaving machine through a warping-weaving process. After weaving, it is dried at 200°C for 2 minutes to finally prepare an inorganic fiber barrier layer with barrier properties; (3) The inorganic fiber barrier layer prepared in (2) is preheated in a 100°C preheating zone, and then the flame retardant adhesive solution prepared in (1) is penetrated into the fiber bundle through a horizontal impregnation tank. The sizing rate (dry adhesive mass / dry cloth mass) is controlled between 50% and 60%. Then it is dried in a multi-temperature zone drying tunnel at 85°C for 7 minutes until constant weight is obtained, and finally a pre-sizing flame retardant inorganic fiber barrier layer is obtained. The resulting pre-adhesive flame-retardant inorganic fiber barrier layer appears as a dry, non-sticky flexible roll or sheet material; the surface is smooth, the adhesive layer evenly wraps the fibers, and the fiber texture is clearly visible but covered by the adhesive layer. When this pre-adhesive flame-retardant inorganic fiber barrier layer is placed between a wood-based panel and a panel veneer, and then hot-pressed, a flame-retardant panel can be obtained, which performs both flame-retardant and barrier functions.

[0019] 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 pre-adhesive flame-retardant inorganic fiber barrier layer for engineered wood panels, characterized in that, Includes the following steps: (1) Synthesis of flame retardant adhesive: A synergistic flame retardant system (component A) is prepared by using inorganic Si, Mg, and Al flame retardants and nitrogen-phosphorus intumescent flame retardants as flame retardant additives. It is mainly composed of one or more of silica, silica powder, magnesium hydroxide, aluminum hydroxide, boehmite, ammonium polyphosphate, guanidine phosphate, and ammonium phytate. The adhesive body (component B) is prepared by using thermosetting adhesive as the adhesive body. It is mainly composed of one or more of phenolic resin, urea-formaldehyde resin, melamine-modified phenolic resin adhesive, melamine-modified urea-formaldehyde resin, and melamine-formaldehyde resin. The flame retardant adhesive is prepared by compounding and blending components A and B. (2) Preparation of inorganic fiber barrier layer: Inorganic fiber is used as warp and weft, and after surface treatment, it is woven by a braiding machine through warping-weaving-post-treatment process to prepare an inorganic fiber barrier layer with barrier properties. (3) Preparation of pre-applied flame-retardant inorganic fiber barrier layer: The inorganic fiber barrier layer impregnated with flame-retardant adhesive is obtained by surface cleaning-impregnation and metering-drying and curing process; Preferably, in step (1), the mass ratio of inorganic Si, Mg, and Al flame retardants to nitrogen-phosphorus intumescent flame retardants in component A is 3:8 to 6:1; preferably, in step (1), the solid content of thermosetting adhesive in component B is 1.5% to 20%, and the dispersion temperature is 15°C to 50°C; preferably, in step (1), the mass ratio of components A and B is 5:5 to 5:1, and the mixture is stirred thoroughly until it is evenly dispersed. Preferably, in step (2), the inorganic fiber is woven from one or more of the following composites: alkali-free glass fiber, high-strength glass fiber, basalt fiber, and ceramic fiber; preferably, in step (2), the woven fabric is subjected to a short-time (1-3 minutes) heat setting treatment at a temperature of 150℃~350℃ during the post-processing. Preferably, in step (3), the fabric is preheated during surface treatment at a temperature of 80°C to 120°C; preferably, in step (3), the ratio of dry adhesive mass to dry fabric mass during impregnation and metering is controlled between 10% and 120%, preferably 40% to 60%; preferably, in step (3), the drying and curing is carried out by low-temperature drying, with the drying temperature controlled between 60°C and 105°C and the drying time controlled between 1 and 13 minutes, to obtain a pre-applied flame-retardant inorganic fiber barrier layer.