New production technology of wooden fire doors

After nearly 20 years of development, there are currently 372 wooden fireproof door manufacturers in my country, 28 fire-retardant timber manufacturers for building interior decoration, 26 fire-retardant plywood and blockboard manufacturers, and fire-retardant decorative panels. There are 15 enterprises, 6 fire-retardant particleboard manufacturers, 4 fire-retardant fiberboard manufacturers, and 111 decorative fire-retardant coating manufacturers.
Except for wooden fire doors, the application of fire-retardant wood and its products in the interior decoration of buildings in my country has not yet been popularized. At present, most of the interior decoration projects of buildings use fire-retardant coatings to protect wood and wood-based panels. Compared with developed countries, there is a very large gap. The main problems are: ① The product varieties and grades cannot meet the needs of the market. ② Constrained by the wood void structure, it is difficult for liquid to penetrate into most of the wood, so most of the wood is difficult to be treated with flame retardant impregnation. ③ The fire-retardant impregnated wood needs to be dried twice. The drying cycle is 15 to 45 days, and the production cycle is longer. ④ When flame retardant impregnation treatment and drying are performed on the veneer, the veneer is damaged greatly and the operation is complicated. ⑤ After flame-retardant treatment, the strength of wood and wood-based panels is reduced by 15-40%, which affects the application of the product.
⑥ The price of fire-retardant treated wood and products is higher. ⑦ The relevant fire protection laws and regulations have not been effectively implemented. The use of fire-retardant coatings for fire protection of wood and its products has the following problems: ① The wood and its products lose the beautiful decorative effect of natural textures. Although the thin transparent fire-retardant coatings have been published, the texture and patterns of natural wood are retained to a certain extent, but With a brushing amount of 500g/m2 or more, the woodiness of the product is significantly reduced; ② After a period of time, the coating will crack, which reduces the fire protection and decoration effects; ③ More than 3 times of painting or spraying work increases the on-site construction Workload and difficulty;

④ Water-soluble fire-resistant coatings have poor waterproof and moisture-proof properties, and solvent-based fire-retardant coatings cause environmental pollution. Currently, there is no decorative fire-retardant coating with a service life of more than 3 years.

New technology of fire-retardant impregnation treatment of wood and its products There are two main fire-retardant treatment methods for wood and its products commonly used at home and abroad, atmospheric pressure method and pressure method. The former includes brushing method, spraying method, immersion treatment method, hot and cold tank method, double diffusion method, etc.; the latter is also called vacuum-pressurization method, including full-cell method, half-cell method, frequency pressure method, circulation method, etc. .
It is usually necessary for the flame retardant to be evenly distributed inside the wood material. In order to improve the permeability and depth of penetration, researchers at home and abroad have proposed the following new impregnation treatment methods. (1) CO2 supercritical fluid treatment of wood technology: This method can treat almost all wood species without obvious adverse effects on the treated wood.
(2) Wood laser scoring method: The laser scoring method does not damage the wood tissue and makes it easy to inject the medicine [3]. Compared with the claw-shaped knife scoring method, the laser scoring method has a 50% increase in the liquid medicine impregnated into the wood.
(3) Low-pressure steam blasting method: Low-pressure steam blasting method can destroy the closed pits, improve the intercellular conductivity and improve the permeability. The electron micrograph shows that the pits are part of the blasting treatment. Selective destruction. (4) Compression pretreatment technology: first compress the wood horizontally to selectively destroy the pit periphery and the pit membrane, and the intrusion body in the orifice tube is also destroyed, which improves the permeability.
(5) Hot water (steam) treatment method: For coniferous woods, hot water (steam) treatment can remove the arabinogalactose gum covering the pores and open the blocked pores, thereby improving Permeability: The greater the strength of the cooking treatment, the greater the effect of improving the permeability. The electron micrographs show that there are cracked pit plugs after the cooking treatment [3]. Using microwave heating to pretreat the wood can not only increase the heating speed, but also improve the permeability of the medicine. (6) Oscillation and pressure treatment method: while the wood is subjected to pressure treatment, a method of oscillating is applied. After the shock treatment, the penetration and absorption of the drug increased significantly.
(7) For the use of enzymes, microorganisms, and bacteria to improve the permeability of wood. (8) Acoustic wave and ultrasonic treatment method: While the wood is pressurized, the effect of sound wave or ultrasonic wave is also a research direction to improve the permeability of wood. (9) Centrifugal rotation treatment technology: the wood is impregnated in a centrifugal separator, and the centrifugal impregnation under normal pressure increases the absorption of the wood to the medicine.

The flame retardant used for new wood materials and treatment process wood flame retardant is mainly based on inorganic P-N series. In order to improve the flame retardant effect and resistance to loss, reduce the moisture absorption rate and toxicity, the following researches are mainly carried out: (1) Choose suitable additives and emulsifiers, and mix the non-water-soluble flame retardants into aqueous solutions or emulsions for wood materials The flame retardant treatment reduces the moisture absorption, loss rate of flame retardant wood materials, and the influence of flame retardants on the strength of wood materials. (2) The double diffusion method is used to generate water-insoluble compounds in the wood material.
(3) Resin-based flame retardants not only impart flame retardant effects to wood materials, but also improve the physical and mechanical properties of wood materials. (4) Research on multifunctional wood material treatment agent with flame retardant, antiseptic and insect proof.
(5) Research on synergists and anti-smoke agents.

Fireproof sheet and its application Fireproof sheet refers to a new type of sheet with a thickness of 0.2~5mm, which can improve the combustion grade and fire resistance of the protected material. It is composed of framework materials, binders and flame retardants. Composition.