Smoke-suppressing layered flame-retardant decorative plywood and its preparation method

Abstract

This invention provides a smoke-suppressing, layered flame-retardant decorative plywood and its preparation method. The method achieves excellent flame-retardant and bonding properties through layered flame retardancy and interfacial cross-linking. The preparation includes: immersing wood veneer successively in a THPE aqueous solution and a phytic acid aqueous solution, or successively in a THPE aqueous solution, an EDTA-2Na aqueous solution, and a phytic acid aqueous solution; removing and drying the veneer to obtain flame-retardant wood veneer; mixing melamine-modified urea-formaldehyde resin and flame retardant A with water, then adding flour and stirring until homogeneous to obtain a flame-retardant adhesive. Flame retardant A is a mixture composed of CS-APP and any one or a combination of soluble starch, sucrose, and glucose; CS-APP is a mixture composed of chitosan and ammonium polyphosphate; using the flame-retardant wood veneer as the upper and lower surface veneers of the plywood to prepare the plywood substrate; applying the flame-retardant adhesive to the upper and lower surfaces of the plywood substrate and then covering it with decorative wood veneer before performing a pressing process.

Description

Technical Field

[0001] This invention relates to the flame-retardant process of decorative plywood, and more particularly to a smoke-suppressing layered flame-retardant decorative plywood and its preparation method. Background Technology

[0002] Traditional veneer plywood often uses impregnation to improve its flammability. However, impregnation of plywood veneer can cause small-molecule flame retardants to leach out as temperature and humidity change. Furthermore, the leachation of flame retardants can break the cross-linked molecular chains of the adhesive at the microscopic interface, thus affecting the bonding strength. Summary of the Invention

[0003] This invention was developed in view of the above problems, and its purpose is to provide a smoke-suppressing layered flame-retardant decorative plywood and its preparation method, which achieves good flame-retardant and bonding performance through layered flame retardancy and interfacial cross-linking.

[0004] Firstly, a method for preparing a smoke-suppressing, layered, flame-retardant decorative plywood is provided, comprising:

[0005] (1) The wood veneer is immersed in a THPE aqueous solution with a concentration of 0.75-1.0 mol / L, pressurized to 0.5-1.2 MPa and maintained for 1-2 h, and then further immersed in a phytic acid aqueous solution with a concentration of 0.5-0.65 mol / L, pressurized to 0.5-1.0 MPa and maintained for 1-2 h, and then the wood veneer is dried at a temperature of 75-80℃ for 30-60 min to obtain flame-retardant wood veneer;

[0006] (2) Melamine-modified urea-formaldehyde resin and flame retardant A are mixed evenly with an appropriate amount of water and left to stand until the pH value of the system is 7.2-7.5. Then flour is added and stirred evenly to obtain a flame retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:(15-28):(6-10). Flame retardant A is a mixture composed of any one or combination of CS-APP and soluble starch, sucrose and glucose in a mass ratio of 1:(0.3-0.6). CS-APP is a mixture composed of chitosan and ammonium polyphosphate in a mass ratio of (1-7):(94-99).

[0007] (3) The flame-retardant wood veneer is used as the upper and lower surface veneers of the plywood to make the plywood substrate. The flame-retardant adhesive is applied to the upper and lower surfaces of the plywood substrate and then decorative wood veneer is applied before pressing.

[0008] A preferred preparation of a smoke-suppressing, layered, flame-retardant decorative plywood is also provided, comprising:

[0009] (1) The wood veneer is immersed in a THPE aqueous solution with a concentration of 0.75-1.0 mol / L, pressurized to 0.5-1.2 MPa and maintained for 1-2 h, then the wood veneer is immersed in an EDTA-2Na aqueous solution with a concentration of 0.3-1.5 mol / L, preferably 0.6-0.9 mol / L, 0.7-0.8 mol / L or 0.75 mol / L, pressurized to 0.5-1.0 MPa and maintained for 1-2 h, then further immersed in a phytic acid aqueous solution with a concentration of 0.5-0.65 mol / L, pressurized to 0.5-1.0 MPa and maintained for 1-2 h, then the wood veneer is removed and dried at 75-80℃ for 30-60 min to obtain flame-retardant wood veneer;

[0010] (2) Melamine-modified urea-formaldehyde resin and flame retardant A are mixed evenly with an appropriate amount of water and left to stand until the pH value of the system is 7.2-7.5. Then flour is added and stirred evenly to obtain a flame retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:(15-28):(6-10). Flame retardant A is a mixture composed of any one or combination of CS-APP and soluble starch, sucrose and glucose in a mass ratio of 1:(0.3-0.6). CS-APP is a mixture composed of chitosan and ammonium polyphosphate in a mass ratio of (1-7):(94-99).

[0011] (3) The flame-retardant wood veneer is used as the upper and lower surface veneers of the plywood to make the plywood substrate. The flame-retardant adhesive is applied to the upper and lower surfaces of the plywood substrate and then decorative wood veneer is applied before pressing.

[0012] In the above two preparations, the order of steps (1) and (2) is not important, and the preparation of flame-retardant wood veneer and flame-retardant adhesive can be carried out separately.

[0013] In the two preparations described above, CS-APP is prepared by the following method: An appropriate amount of ammonium polyphosphate is added to a saturated chitosan-acetic acid solution and stirred until homogeneous. The mixture is then filtered and dried to obtain powder. The obtained powder is further added to a saturated chitosan-acetic acid solution and stirred until homogeneous. This process of adding the obtained powder to the saturated chitosan-acetic acid solution, stirring until homogeneous, and then filtering and drying to obtain powder is preferably repeated at least twice, more preferably 5 to 10 times.

[0014] In both of the above preparation processes, flame-retardant wood veneers are used as the top and bottom surface veneers, and untreated flame-retardant wood veneers are used as the core veneers for assembly. Adhesive is applied between the veneers, followed by a pressing process. The adhesive is applied by coating, with a coating amount of 200–220 g / m². 2The pressing process includes sequential cold pressing and hot pressing. The cold pressing pressure is 0.1–0.2 MPa, and the cold pressing time is 40–50 min. The hot pressing pressure is 1–2 MPa, and the hot pressing time is 45–48 min. The hot pressing temperature is 120–145°C. Further, the adhesive applied between the plates can be a urea-formaldehyde resin adhesive or a phenolic resin adhesive.

[0015] In both of the above preparations, the flame-retardant adhesive is applied by coating, with a coating amount of 170–190 g / m³. 2 The pressing process after applying decorative wood veneer includes: placing the pre-formed board with the applied decorative wood veneer in a cold press with a pressure of 0.1-0.2 MPa for 35-45 minutes, and then transferring it to a hot press with a temperature of 100-120℃ and a pressure of 1-1.5 MPa for 300-420 seconds.

[0016] In addition, smoke-suppressing layered flame-retardant decorative plywood prepared by the above two preparation methods is also provided.

[0017] According to the board manufacturing technology of the present invention, flame-retardant veneers are placed on the upper and lower surfaces of plywood, which are then coated with flame-retardant urea-formaldehyde resin adhesive by roller coating. The following beneficial effects are achieved, based on mechanism and experimental verification.

[0018] The flame-retardant adhesive layer and the flame-retardant veneer layer form a layered flame retardant structure. Above the interface, in the surface adhesive layer, melamine, chitosan-modified ammonium polyphosphate, and soluble starch and other sugars form a porous carbon layer through the interaction of gas source, enhanced acid source, and carbon source. Below the interface, in the veneer layer, with the pyrolysis, the phosphorus oxygen free radicals formed by the pyrolysis of phytic acid further capture the volatile components of incomplete combustion, thereby improving the flame retardant efficiency.

[0019] Flame-retardant adhesives, by adding chitosan and compounding with soluble starch, sucrose, glucose, and other polyhydroxy sugars, can form van der Waals forces with the lignin and other hydroxyl groups in the chemical structure of wood veneer during cold pressing, creating chemically stable adhesive nails. During hot pressing, some of the weaker van der Waals forces cross-link through phytic acid branching and THPE hydroxyl groups to form a stable chemical structure, further enhancing the stability of the adhesive nails. This relatively stable chemical interaction at the interface, through the formation of chemically stable adhesive nails, increases the thermal decomposition temperature during combustion and simultaneously promotes the formation of a dense char layer at the interface.

[0020] During the heating and drying process after impregnation of flame-retardant veneer, a hydroxyl cross-linking reaction occurs between the hydroxyl groups on the wood, the hydroxyl groups on THPE, and the hydroxyl groups on phytic acid. This enhances the thermal stability of the flame retardant in the surface veneer of the plywood substrate. Not only does the cross-linking structure facilitate the formation of a dense char layer during combustion, but the flame-retardant components are also less likely to be lost.

[0021] The further addition of EDTA-2Na catalyzes the reaction between THPE and phytic acid. As a small-molecule branched acid source, EDTA-2Na supplements the main acid source, phytic acid, during combustion, rapidly promoting char formation in the early stages of combustion. Furthermore, THPE and EDTA-2Na form char at different degrees, corresponding to different combustion stages, thus improving the flame-retardant effect. The flame-retardant performance is particularly optimal when the concentration of EDTA-2Na aqueous solution is around 0.75 mol / L, indicating that at this concentration, THPE and EDTA-2Na promote the formation of a denser char layer. Attached Figure Description

[0022] Figure 1 This is a schematic diagram illustrating the structure of the decorative plywood with multi-layer flame-retardant treatment according to the present invention. Detailed Implementation

[0023] Veneered plywood is a type of engineered wood panel used for decoration, also known as veneered plywood. It is made by pressing a veneer layer onto a plywood substrate using a specific pressing process. In this invention, the veneer layer is a decorative wood veneer, specifically, for example, planed solid wood veneer or reconstituted decorative veneer.

[0024] Solid wood veneer is made from thin slices of logs, which can be processed through multiple steps such as high-temperature painting. Reconstituted decorative veneer is made by laminating and molding sliced ​​or rotary-dried solid wood chips. There are no restrictions on the species of solid wood used; for example, poplar, teak, walnut, birch, eucalyptus, ash, etc., any wood species that can be used for decorative surfaces within the industry and possesses the corresponding properties is included in the solid wood materials used for reconstituted decorative veneer.

[0025] This embodiment provides a method for applying a flame-retardant veneer to plywood with flame-retardant urea-formaldehyde resin adhesive via roller coating, thereby achieving a layered flame-retardant structure. The flame-retardant veneer is made of wood veneer that has undergone flame-retardant impregnation treatment, forming a char-forming interface with the flame-retardant urea-formaldehyde resin adhesive. (Refer to...) Figure 1 The diagram shown illustrates the structure of a typical fire-retardant veneer plywood according to the present invention. The fire-retardant veneer plywood consists of plywood as a base material and a veneer layer. The plywood is assembled from fire-retardant veneers with fire-retardant impregnation treatment on the upper and lower surfaces and ordinary veneers as the core layer. Ordinary adhesive is applied between the veneers to form an ordinary adhesive layer. The upper and lower veneer layers are both composed of decorative wood veneers, which are assembled with the plywood and fire-retardant adhesive is applied between the veneers to form a fire-retardant adhesive layer.

[0026] The flame-retardant urea-formaldehyde resin adhesive is obtained by uniformly mixing melamine-modified urea-formaldehyde resin and flame retardant A with an appropriate amount of water, then adding flour and stirring until homogeneous. Specifically, the mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A, and flour is 85:(15-28):(6-10), wherein flame retardant A is a mixture composed of any one or combination of CS-APP and soluble starch, sucrose, and glucose in a mass ratio of 1:(0.3-0.6), and CS-APP is a mixture composed of chitosan and ammonium polyphosphate in a mass ratio of (1-7):(94-99).

[0027] Flame retardant A is prepared by uniformly mixing CS-APP with any one or a combination of soluble starch, sucrose, and glucose.

[0028] CS-APP is prepared by the following method: an appropriate amount of ammonium polyphosphate is added to a saturated chitosan acetic acid solution and stirred evenly, then filtered and dried to obtain powder. The obtained powder is further added to a saturated chitosan acetic acid solution and stirred evenly, then filtered and dried to obtain powder.

[0029] Repeating the cycle of adding the obtained powder to a saturated chitosan-acetic acid solution, stirring until homogeneous, filtering and drying to obtain the powder, can create a microstructure in which ammonium polyphosphate and chitosan encapsulate each other, resulting in a denser char layer during combustion. This cycle can be repeated more than twice. As the number of cycles increases, the flame retardant performance improves, but considering the balance between cost and effectiveness, 5 to 10 cycles are preferred.

[0030] The flame-retardant impregnation treatment of wood veneer involves impregnation with three flame-retardant components, as detailed below:

[0031] 1. THPE aqueous solution.

[0032] THPE is tetrahydroxypropylethylenediamine, and its structural formula is as follows.

[0033]

[0034] 2. EDTA-2Na aqueous solution.

[0035] EDTA-2Na is disodium ethylenediaminetetraacetate, and its structural formula is as follows.

[0036]

[0037] 3. Phytic acid aqueous solution.

[0038] The structural formula of phytic acid is as follows.

[0039]

[0040] During the heating and drying process after impregnation, a hydroxyl cross-linking reaction occurs between the hydroxyl groups on the wood, the hydroxyl groups on THPE, and the hydroxyl groups on phytic acid. This enhances the thermal stability of the flame retardant in the surface veneer of the plywood substrate. Not only does the cross-linking structure facilitate the formation of a dense char layer during combustion, but the flame retardant components are also less likely to be lost. Furthermore, the addition of EDTA-2Na acts as a catalyst in the reaction between THPE and phytic acid, and works with THPE to promote the formation of a better dense char layer.

[0041] The following specific embodiments and comparative examples clearly illustrate the substantial innovation and significant technical effects of the present invention.

[0042] Example 1:

[0043] Preparation of materials:

[0044] 1. Wood veneer: 1.2mm thick poplar veneer

[0045] 2. Decorative veneer: 0.2mm thick poplar veneer

[0046] 3. Melamine-modified urea-formaldehyde resin

[0047] The solid content is 58%, and the melamine content is 10% (as a percentage of the total urea content);

[0048] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0049] 4. Flame retardant A

[0050] It was obtained by uniformly mixing CS-APP and soluble starch (purchased from Aladdin Biochemical Technology, with an active ingredient content of ≥99%) at a mass ratio of 1:0.3.

[0051] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0052] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid solvent until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added and stirred evenly. After filtration and drying, powder 1 was obtained. Powder 1 was then added to the saturated chitosan acetic acid solution and stirred evenly. After filtration and drying, chitosan-modified ammonium polyphosphate powder CS-APP was obtained, with CS content of 1 wt% and APP content of 99 wt%.

[0053] 5. Treatment solution 1

[0054] 0.75 mol / L tetrahydroxypropylethylenediamine aqueous solution (THPE aqueous solution)

[0055] 6. Treatment liquid 2

[0056] 0.50 mol / L phytic acid aqueous solution

[0057] 7. Flour (industrial grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0058] 8. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water to adjust the solid content to 58% before application, purchased from Guangzhou Yuanye Chemical).

[0059] preparation:

[0060] Step 1 (Flame-retardant impregnation treatment of veneer):

[0061] A certain number of wood veneers are placed in a vacuum pressure impregnation tank. Treatment solution 1 is injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covers the wood veneers. The pressure is increased to 0.5MPa and maintained for 1 hour. Then, the pressure is reduced to normal pressure 0.2MPa and the treatment solution 1 is extracted. Treatment solution 2 is then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure is increased to 0.5MPa and maintained for 1 hour. The wood veneers are then removed and placed in a forced-air drying oven to dry at 80℃ for 30 minutes to obtain flame-retardant veneers.

[0062] Step 2 (Preparation of flame-retardant adhesive):

[0063] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.2. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:15:6.

[0064] Step 3 (Plywood substrate assembly process):

[0065] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process, wherein the ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer at a coating amount of 220 g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The cold pressing pressure is 0.1 MPa and the cold pressing time is 40 min. The hot pressing pressure is 2 MPa and the hot pressing time is 45 min. The hot pressing temperature is 120℃.

[0066] Step 4 (Decorative Panel Assembly Process):

[0067] Flame-retardant adhesive is applied to the top and bottom surfaces of the plywood substrate using a gluing machine, with a coating amount of 170 g / m². 2The blanks are then covered with decorative veneers to form a preform, and then subjected to a pressing process. The pressing process includes: placing the blank in a cold press with a pressure of 0.1 MPa for 45 minutes, and then transferring it to a hot press with a temperature of 100℃ and a pressure of 1 MPa for 300 seconds, thereby obtaining a smoke-suppressing, layered, flame-retardant decorative veneer plywood.

[0068] test:

[0069] The prepared smoke-suppressing, layered, flame-retardant decorative veneer plywood was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0070] Oxygen index: 31.5%

[0071] Peak heat release rate: 202.43 kW / m 2

[0072] Total flue gas emission: 238.29 m³ 2 / m 2

[0073] Surface adhesive strength: 0.58 MPa

[0074] Example 2:

[0075] Preparation of materials:

[0076] 1. Wood veneer: 1.2mm thick poplar veneer

[0077] 2. Decorative veneer: 0.2mm thick poplar veneer

[0078] 3. Melamine-modified urea-formaldehyde resin

[0079] The solid content is 58%, and the melamine content is 10% (as a percentage of the total urea content);

[0080] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0081] 4. Flame retardant A

[0082] It was obtained by uniformly mixing CS-APP and soluble starch (purchased from Aladdin Biochemical Technology, with an active ingredient content of ≥99%) at a mass ratio of 1:0.3.

[0083] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0084] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added, stirred evenly, filtered, and dried to obtain powder 1. Powder 1 was then added to the saturated chitosan-acetic acid solution, stirred evenly, filtered, and dried. This process was repeated three times to obtain chitosan-modified ammonium polyphosphate powder CS-APP, with a CS content of 3.5 wt% and an APP content of 96.5 wt%.

[0085] 5. Treatment solution 1

[0086] 0.75 mol / L tetrahydroxypropylethylenediamine aqueous solution (THPE aqueous solution)

[0087] 6. Treatment liquid 2

[0088] 0.50 mol / L phytic acid aqueous solution

[0089] 7. Flour (industrial grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0090] 8. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water before application to adjust the solid content to 58%, purchased from Guangzhou Yuanye Chemical).

[0091] preparation:

[0092] Step 1 (Flame-retardant impregnation treatment of veneer):

[0093] A certain number of wood veneers are placed in a vacuum pressure impregnation tank. Treatment solution 1 is injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covers the wood veneers. The pressure is increased to 0.5MPa and maintained for 1 hour. Then, the pressure is reduced to normal pressure 0.2MPa and the treatment solution 1 is extracted. Treatment solution 2 is then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure is increased to 0.5MPa and maintained for 1 hour. The wood veneers are then removed and placed in a forced-air drying oven to dry at 80℃ for 30 minutes to obtain flame-retardant veneers.

[0094] Step 2 (Preparation of flame-retardant adhesive):

[0095] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.2. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:15:6.

[0096] Step 3 (Plywood substrate assembly process):

[0097] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process, wherein the ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer at a coating amount of 220 g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The cold pressing pressure is 0.1 MPa and the cold pressing time is 40 min. The hot pressing pressure is 2 MPa and the hot pressing time is 45 min. The hot pressing temperature is 120℃.

[0098] Step 4 (Decorative Panel Assembly Process):

[0099] Flame-retardant adhesive is applied to the top and bottom surfaces of the plywood substrate using a gluing machine, with a coating amount of 170 g / m². 2 The blanks are then covered with decorative veneers to form a preform, and then subjected to a pressing process. The pressing process includes: placing the blank in a cold press with a pressure of 0.1 MPa for 45 minutes, and then transferring it to a hot press with a temperature of 100℃ and a pressure of 1 MPa for 300 seconds, thereby obtaining a smoke-suppressing, layered, flame-retardant decorative veneer plywood.

[0100] test:

[0101] The prepared smoke-suppressing, layered, flame-retardant decorative veneer plywood was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0102] Oxygen index: 33.5%

[0103] Peak heat release rate: 196.38 kW / m 2

[0104] Total flue gas emission: 227.01m³ 2 / m 2

[0105] Surface adhesive strength: 0.60 MPa

[0106] Example 3:

[0107] Preparation of materials:

[0108] 1. Wood veneer: 1.2mm thick poplar veneer

[0109] 2. Decorative veneer: 0.2mm thick poplar veneer

[0110] 3. Melamine-modified urea-formaldehyde resin

[0111] The solid content is 58%, and the melamine content is 10% (as a percentage of the total urea content);

[0112] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0113] 4. Flame retardant A

[0114] It was obtained by uniformly mixing CS-APP and soluble starch (purchased from Aladdin Biochemical Technology, with an active ingredient content of ≥99%) at a mass ratio of 1:0.3.

[0115] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0116] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added and stirred evenly. After filtration and drying, powder 1 was obtained. Powder 1 was then added to the saturated chitosan-acetic acid solution and stirred evenly. After filtration and drying, the process was repeated 7 times. Chitosan-modified ammonium polyphosphate powder CS-APP was obtained, with a CS content of 6.8 wt% and an APP content of 93.2 wt%.

[0117] 5. Treatment solution 1

[0118] 0.75 mol / L tetrahydroxypropylethylenediamine aqueous solution (THPE aqueous solution)

[0119] 6. Treatment liquid 2

[0120] 0.50 mol / L phytic acid aqueous solution

[0121] 7. Flour (industrial grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0122] 8. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water before application to adjust the solid content to 58%, purchased from Guangzhou Yuanye Chemical).

[0123] preparation:

[0124] Step 1 (Flame-retardant impregnation treatment of veneer):

[0125] A certain number of wood veneers are placed in a vacuum pressure impregnation tank. Treatment solution 1 is injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covers the wood veneers. The pressure is increased to 0.5MPa and maintained for 1 hour. Then, the pressure is reduced to normal pressure 0.2MPa and the treatment solution 1 is extracted. Treatment solution 2 is then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure is increased to 0.5MPa and maintained for 1 hour. The wood veneers are then removed and placed in a forced-air drying oven to dry at 80℃ for 30 minutes to obtain flame-retardant veneers.

[0126] Step 2 (Preparation of flame-retardant adhesive):

[0127] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.2. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:15:6.

[0128] Step 3 (Plywood substrate assembly process):

[0129] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process, wherein the ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer at a coating amount of 220 g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The hot pressing pressure is 2 MPa, the hot pressing time is 45 min, and the hot pressing temperature is 120℃. The cold pressing pressure is 0.1 MPa, and the cold pressing time is 40 min.

[0130] Step 4 (Decorative Panel Assembly Process):

[0131] Flame-retardant adhesive is applied to the top and bottom surfaces of the plywood substrate using a gluing machine, with a coating amount of 170 g / m². 2 The blanks are then covered with decorative veneers to form a preform, and then subjected to a pressing process. The pressing process includes: placing the blank in a cold press with a pressure of 0.1 MPa for 45 minutes, and then transferring it to a hot press with a temperature of 100℃ and a pressure of 1 MPa for 300 seconds, thereby obtaining a smoke-suppressing, layered, flame-retardant decorative veneer plywood.

[0132] test:

[0133] The prepared smoke-suppressing, layered, flame-retardant decorative veneer plywood was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0134] Oxygen index: 34.7%

[0135] Peak heat release rate: 192.33 kW / m 2

[0136] Total flue gas emission: 209.09m³ 2 / m 2

[0137] Surface adhesive strength: 0.64 MPa

[0138] Example 4:

[0139] Preparation of materials:

[0140] 1. Wood veneer: 3.6mm thick eucalyptus veneer

[0141] 2. Decorative veneer: 0.2mm thick eucalyptus veneer

[0142] 3. Melamine-modified urea-formaldehyde resin

[0143] The solid content is 56%, and the melamine content is 8% (as a percentage of the total urea content);

[0144] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0145] 4. Flame retardant A

[0146] It was obtained by uniformly mixing CS-APP and sucrose (purity ≥99% white granulated sugar, purchased from Aladdin Biochemical Technology) at a mass ratio of 1:0.5.

[0147] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0148] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added and stirred evenly. After filtration and drying, powder 1 was obtained. Powder 1 was then added to the saturated chitosan-acetic acid solution and stirred evenly. After filtration and drying, the process was repeated 7 times. Chitosan-modified ammonium polyphosphate powder CS-APP was obtained, with a CS content of 6.8 wt% and an APP content of 93.2 wt%.

[0149] 5. Treatment solution 1

[0150] 0.85 mol / L tetrahydroxypropylethylenediamine aqueous solution (THPE aqueous solution)

[0151] 6. Treatment liquid 2

[0152] 0.60 mol / L phytic acid aqueous solution

[0153] 7. Flour (industrial grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0154] 8. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water to adjust the solid content to 58% before application, purchased from Guangzhou Yuanye Chemical).

[0155] preparation:

[0156] Step 1 (Flame-retardant impregnation treatment of veneer):

[0157] A certain number of wood veneers are placed in a vacuum pressure impregnation tank. Treatment solution 1 is injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covers the wood veneers. The pressure is increased to 1.2MPa and maintained for 2 hours. After returning to normal pressure 0.2MPa, treatment solution 1 is extracted. Treatment solution 2 is then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure is increased to 0.8MPa and maintained for 1.5 hours. The wood veneers are then removed and placed in a forced-air drying oven to dry at 75℃ for 60 minutes to obtain flame-retardant veneers.

[0158] Step 2 (Preparation of flame-retardant adhesive):

[0159] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.5. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:28:10.

[0160] Step 3 (Plywood substrate assembly process):

[0161] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process. The ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer, with an adhesive application rate of 220 g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The hot pressing pressure is 1 MPa, the hot pressing time is 48 min, and the hot pressing temperature is 145℃. The cold pressing pressure is 0.15 MPa, and the cold pressing time is 45 min.

[0162] Step 4 (Decorative Panel Assembly Process):

[0163] Flame-retardant adhesive is applied to the top and bottom surfaces of the plywood substrate using a gluing machine, with a coating amount of 185 g / m². 2 The plywood is then assembled by covering each plywood with decorative veneer, and then subjected to a pressing process. The pressing process includes placing the plywood in a cold press with a pressure of 0.2 MPa for 40 minutes, and then transferring it to a hot press with a temperature of 120℃ and a pressure of 1.5 MPa for 330 seconds. This process yields smoke-suppressing, layered, flame-retardant decorative veneer plywood.

[0164] test:

[0165] The prepared smoke-suppressing, layered, flame-retardant decorative veneer plywood was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0166] Oxygen index: 35.1%

[0167] Peak heat release rate: 189.47 kW / m2

[0168] Total flue gas emission: 198.15m³ 2 / m 2

[0169] Surface adhesive strength: 0.66 MPa

[0170] Example 5:

[0171] Preparation of materials:

[0172] 1. Wood veneer: 3.6mm thick eucalyptus veneer

[0173] 2. Decorative veneer: 0.40mm thick poplar veneer

[0174] 3. Melamine-modified urea-formaldehyde resin

[0175] The solid content is 56%, and the melamine content is 9% (as a percentage of the total urea content);

[0176] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0177] 4. Flame retardant A

[0178] It was obtained by uniformly mixing CS-APP and glucose (industrial grade glucose powder, 99% effective ingredient, purchased from Aladdin Biochemical Technology) at a mass ratio of 1:0.6.

[0179] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0180] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added and stirred evenly. After filtration and drying, powder 1 was obtained. Powder 1 was then added to the saturated chitosan-acetic acid solution and stirred evenly. After filtration and drying, the process was repeated 7 times. Chitosan-modified ammonium polyphosphate powder CS-APP was obtained, with a CS content of 6.8 wt% and an APP content of 93.2 wt%.

[0181] 5. Treatment solution 1

[0182] A 1.0 mol / L aqueous solution of tetrahydroxypropyl ethylenediamine (THPE)

[0183] 6. Treatment liquid 2

[0184] 0.65 mol / L phytic acid aqueous solution

[0185] 7. Flour (industrial grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0186] 8. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water before application to adjust the solid content to 58%, purchased from Guangzhou Yuanye Chemical).

[0187] preparation:

[0188] Step 1 (Flame-retardant impregnation treatment of veneer):

[0189] A certain number of wood veneers are placed in a vacuum pressure impregnation tank. Treatment solution 1 is injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covers the wood veneers. The pressure is increased to 1.0MPa and maintained for 1.5 hours. After returning to normal pressure 0.2MPa, treatment solution 1 is extracted. Treatment solution 2 is then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure is increased to 1.0MPa and maintained for 2 hours. The wood veneers are then removed and placed in a forced-air drying oven to dry at 75℃ for 45 minutes to obtain flame-retardant veneers.

[0190] Step 2 (Preparation of flame-retardant adhesive):

[0191] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.3. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:14:7.

[0192] Step 3 (Plywood substrate assembly process):

[0193] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process, wherein the ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer at a rate of 200 g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The hot pressing pressure is 1.5 MPa, the hot pressing time is 48 min, and the hot pressing temperature is 125℃. The cold pressing pressure is 0.1 MPa, and the cold pressing time is 50 min.

[0194] Step 4 (Decorative Panel Assembly Process):

[0195] Flame-retardant adhesive is applied to the top and bottom surfaces of the plywood substrate using a gluing machine, with a coating amount of 190 g / m². 2 The plywood is then assembled by covering each plywood with decorative veneer, and then subjected to a pressing process. The pressing process includes placing the plywood in a cold press with a pressure of 0.1 MPa for 35 minutes, and then transferring it to a hot press with a temperature of 115℃ and a pressure of 1.3 MPa for 420 seconds. This process yields smoke-suppressing, layered, flame-retardant decorative veneer plywood.

[0196] test:

[0197] The prepared smoke-suppressing, layered, flame-retardant decorative veneer plywood was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0198] Oxygen index: 34.9%

[0199] Peak heat release rate: 190.77 kW / m 2

[0200] Total flue gas emission: 207.19m³ 2 / m 2 .

[0201] Surface adhesive strength: 0.65 MPa

[0202] Example 6:

[0203] Preparation of materials:

[0204] 1. Wood veneer: 1.2mm thick poplar veneer

[0205] 2. Decorative veneer: 0.2mm thick poplar veneer

[0206] 3. Melamine-modified urea-formaldehyde resin

[0207] The solid content is 58%, and the melamine content is 10% (as a percentage of the total urea content);

[0208] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0209] 4. Flame retardant A

[0210] It was obtained by uniformly mixing CS-APP and soluble starch (purchased from Aladdin Biochemical Technology, with an active ingredient content of ≥99%) at a mass ratio of 1:0.3.

[0211] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0212] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added, stirred until homogeneous, filtered, and dried to obtain powder 1. Powder 1 was then added to the saturated chitosan-acetic acid solution, stirred until homogeneous, filtered, and dried. This process was repeated 7 times to obtain chitosan-modified ammonium polyphosphate powder CS-APP, with a CS content of 6.8 wt% and an APP content of 93.2 wt%.

[0213] 5. Treatment solution 1

[0214] 0.75 mol / L tetrahydroxypropylethylenediamine aqueous solution (THPE aqueous solution)

[0215] 6. Treatment liquid 2

[0216] 0.50 mol / L phytic acid aqueous solution

[0217] 7. Treatment liquid 3

[0218] 0.35 mol / L EDTA-2Na aqueous solution (disodium ethylenediaminetetraacetate)

[0219] 8. Flour (industrial grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0220] 9. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water to adjust the solid content to 58% before application, purchased from Guangzhou Yuanye Chemical).

[0221] preparation:

[0222] Step 1 (Flame-retardant impregnation treatment of veneer):

[0223] A certain number of wood veneers were placed in a vacuum pressure impregnation tank. Treatment solution 1 was injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covered the wood veneers. The pressure was increased to 0.5MPa and maintained for 1 hour. Then, the pressure was reduced to normal pressure 0.2MPa and the treatment solution 1 was extracted. Treatment solution 3 was then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure was increased to 0.5MPa and maintained for 1 hour. Then, the pressure was reduced to normal pressure 0.2MPa and the treatment solution 3 was extracted. Treatment solution 2 was then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure was increased to 0.5MPa and maintained for 1 hour. The wood veneers were then removed and placed in a forced-air drying oven and dried at 80℃ for 30 minutes to obtain flame-retardant veneers.

[0224] Step 2 (Preparation of flame-retardant adhesive):

[0225] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.2. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:15:6.

[0226] Step 3 (Plywood substrate assembly process):

[0227] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process, wherein the ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer at a coating amount of 220 g / m². 2After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The hot pressing pressure is 2 MPa, the hot pressing time is 45 min, and the hot pressing temperature is 120℃. The cold pressing pressure is 0.1 MPa, and the cold pressing time is 40 min.

[0228] Step 4 (Decorative Panel Assembly Process):

[0229] Flame-retardant adhesive is applied to the top and bottom surfaces of the plywood substrate using a gluing machine, with a coating amount of 170 g / m². 2 The plywood is then assembled by covering each plywood with decorative veneer, and then subjected to a pressing process. The pressing process includes placing the plywood in a cold press with a pressure of 0.1 MPa for 45 minutes, and then transferring it to a hot press with a temperature of 100℃ and a pressure of 1 MPa for 300 seconds. This yields a preferred smoke-suppressing, layered flame-retardant decorative veneer plywood.

[0230] test:

[0231] The selected smoke-suppressing, layered flame-retardant decorative veneer plywood was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0232] Oxygen index: 37.5%

[0233] Peak heat release rate: 188.23 kW / m 2

[0234] Total flue gas emission: 186.92m³ 2 / m 2

[0235] Surface adhesive strength: 0.68 MPa

[0236] Example 7:

[0237] Preparation of materials:

[0238] 1. Wood veneer: 1.2mm thick poplar veneer

[0239] 2. Decorative veneer: 0.2mm thick poplar veneer

[0240] 3. Melamine-modified urea-formaldehyde resin

[0241] The solid content is 58%, and the melamine content is 10% (as a percentage of the total urea content);

[0242] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0243] 4. Flame retardant A

[0244] It was obtained by uniformly mixing CS-APP and soluble starch (purchased from Aladdin Biochemical Technology, with an active ingredient content of ≥99%) at a mass ratio of 1:0.3.

[0245] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0246] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added, stirred until homogeneous, filtered, and dried to obtain powder 1. Powder 1 was then added to the saturated chitosan-acetic acid solution, stirred until homogeneous, filtered, and dried. This process was repeated 7 times to obtain chitosan-modified ammonium polyphosphate powder CS-APP, with a CS content of 6.8 wt% and an APP content of 93.2 wt%.

[0247] 5. Treatment solution 1

[0248] 0.75 mol / L tetrahydroxypropylethylenediamine aqueous solution (THPE aqueous solution)

[0249] 6. Treatment liquid 2

[0250] 0.50 mol / L phytic acid aqueous solution

[0251] 7. Treatment liquid 3

[0252] 0.75 mol / L EDTA-2Na aqueous solution (disodium ethylenediaminetetraacetate)

[0253] 8. Flour (industrial grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0254] 9. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water to adjust the solid content to 58% before application, purchased from Guangzhou Yuanye Chemical).

[0255] preparation:

[0256] Step 1 (Flame-retardant impregnation treatment of veneer):

[0257] A certain number of wood veneers were placed in a vacuum pressure impregnation tank. Treatment solution 1 was injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covered the wood veneers. The pressure was increased to 0.5MPa and maintained for 1 hour. Then, the pressure was reduced to normal pressure 0.2MPa and the treatment solution 1 was extracted. Treatment solution 3 was injected directly into the impregnation tank (at normal pressure 0.2MPa) and the pressure was increased to 0.8MPa and maintained for 1.5 hours. Then, the pressure was reduced to normal pressure 0.2MPa and the treatment solution 3 was extracted. Treatment solution 2 was injected directly into the impregnation tank (at normal pressure 0.2MPa) and the pressure was increased to 0.5MPa and maintained for 1 hour. The wood veneers were then removed and placed in a forced-air drying oven and dried at 80℃ for 30 minutes to obtain flame-retardant veneers.

[0258] Step 2 (Preparation of flame-retardant adhesive):

[0259] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.2. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:15:6.

[0260] Step 3 (Plywood substrate assembly process):

[0261] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process, wherein the ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer at a coating amount of 220 g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The hot pressing pressure is 2 MPa, the hot pressing time is 45 min, and the hot pressing temperature is 120℃. The cold pressing pressure is 0.1 MPa, and the cold pressing time is 40 min.

[0262] Step 4 (Decorative Panel Assembly Process):

[0263] Flame-retardant adhesive is applied to the top and bottom surfaces of the plywood substrate using a gluing machine, with a coating amount of 170 g / m². 2 The plywood is then assembled by covering each plywood with decorative veneer, and then subjected to a pressing process. The pressing process includes placing the plywood in a cold press with a pressure of 0.1 MPa for 45 minutes, and then transferring it to a hot press with a temperature of 100℃ and a pressure of 1 MPa for 300 seconds. This yields a preferred smoke-suppressing, layered flame-retardant decorative veneer plywood.

[0264] test:

[0265] The selected smoke-suppressing, layered flame-retardant decorative veneer plywood was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0266] Oxygen index: 38.9%

[0267] Peak heat release rate: 182.75 kW / m 2

[0268] Total flue gas emission: 179.64 m³ 2 / m 2

[0269] Surface adhesive strength: 0.73 MPa

[0270] Example 8:

[0271] Preparation of materials:

[0272] 1. Wood veneer: 1.2mm thick poplar veneer

[0273] 2. Decorative veneer: 0.2mm thick poplar veneer

[0274] 3. Melamine-modified urea-formaldehyde resin

[0275] The solid content is 58%, and the melamine content is 10% (as a percentage of the total urea content);

[0276] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0277] 4. Flame retardant A

[0278] It was obtained by uniformly mixing CS-APP and soluble starch (purchased from Aladdin Biochemical Technology, with an active ingredient content of ≥99%) at a mass ratio of 1:0.3.

[0279] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0280] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added, stirred until homogeneous, filtered, and dried to obtain powder 1. Powder 1 was then added to the saturated chitosan-acetic acid solution, stirred until homogeneous, filtered, and dried. This process was repeated 7 times to obtain chitosan-modified ammonium polyphosphate powder CS-APP, with a CS content of 6.8 wt% and an APP content of 93.2 wt%.

[0281] 5. Treatment solution 1

[0282] 0.75 mol / L tetrahydroxypropylethylenediamine aqueous solution (THPE aqueous solution)

[0283] 6. Treatment liquid 2

[0284] 0.50 mol / L phytic acid aqueous solution

[0285] 7. Treatment liquid 3

[0286] 1.40 mol / L EDTA-2Na aqueous solution (disodium ethylenediaminetetraacetate)

[0287] 8. Flour (industrial grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0288] 9. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water to adjust the solid content to 58% before application, purchased from Guangzhou Yuanye Chemical).

[0289] preparation:

[0290] Step 1 (Flame-retardant impregnation treatment of veneer):

[0291] A certain number of wood veneers were placed in a vacuum pressure impregnation tank. Treatment solution 1 was injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covered the wood veneers. The pressure was increased to 0.5MPa and maintained for 1 hour. Then, the pressure was reduced to normal pressure 0.2MPa and the treatment solution 1 was extracted. Treatment solution 3 was then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure was increased to 1.0MPa and maintained for 2 hours. Then, the pressure was reduced to normal pressure 0.2MPa and the treatment solution 3 was extracted. Treatment solution 2 was then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure was increased to 0.5MPa and maintained for 1 hour. The wood veneers were then removed and placed in a forced-air drying oven and dried at 80℃ for 30 minutes to obtain flame-retardant veneers.

[0292] Step 2 (Preparation of flame-retardant adhesive):

[0293] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.2. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:15:6.

[0294] Step 3 (Plywood substrate assembly process):

[0295] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process, wherein the ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer at a coating amount of 220 g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The hot pressing pressure is 2 MPa, the hot pressing time is 45 min, and the hot pressing temperature is 120℃. The cold pressing pressure is 0.1 MPa, and the cold pressing time is 40 min.

[0296] Step 4 (Decorative Panel Assembly Process):

[0297] Flame-retardant adhesive is applied to the top and bottom surfaces of the plywood substrate using a gluing machine, with a coating amount of 170 g / m². 2 The blanks are then covered with decorative veneers to form a preform, and then subjected to a pressing process. The pressing process includes: placing the blank in a cold press with a pressure of 0.1 MPa for 45 minutes, and then transferring it to a hot press with a temperature of 100℃ and a pressure of 1 MPa for 300 seconds, thereby obtaining a smoke-suppressing, layered, flame-retardant decorative veneer plywood.

[0298] test:

[0299] The selected smoke-suppressing, layered flame-retardant decorative veneer plywood was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0300] Oxygen index: 38.3%

[0301] Peak heat release rate: 186.83 kW / m 2

[0302] Total flue gas emission: 186.79m³ 2 / m 2

[0303] Surface adhesive strength: 0.70 MPa

[0304] Comparative Example 1:

[0305] Preparation of materials:

[0306] 1. Wood veneer: 1.2mm thick poplar veneer

[0307] 2. Decorative veneer: 0.2mm thick poplar veneer

[0308] 3.. Treatment solution 1

[0309] 0.75 mol / L tetrahydroxypropylethylenediamine aqueous solution (THPE aqueous solution)

[0310] 4. Treatment liquid 2

[0311] 0.50 mol / L phytic acid aqueous solution

[0312] 5. Flour (industrial-grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0313] 6. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water to adjust the solid content to 58% before application, purchased from Guangzhou Yuanye Chemical).

[0314] preparation:

[0315] Step 1 (Flame-retardant impregnation treatment of veneer):

[0316] A certain number of wood veneers are placed in a vacuum pressure impregnation tank. Treatment solution 1 is injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covers the wood veneers. The pressure is increased to 0.5MPa and maintained for 1 hour. Then, the pressure is reduced to normal pressure 0.2MPa and the treatment solution 1 is extracted. Treatment solution 2 is then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure is increased to 0.5MPa and maintained for 1 hour. The wood veneers are then removed and placed in a forced-air drying oven to dry at 80℃ for 30 minutes to obtain flame-retardant veneers.

[0317] Step 2 (Plywood Substrate Assembly Process):

[0318] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process, wherein the ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer at a coating amount of 220 g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The hot pressing pressure is 2 MPa, the hot pressing time is 45 min, and the hot pressing temperature is 120℃. The cold pressing pressure is 0.1 MPa, and the cold pressing time is 40 min.

[0319] Step 3 (Decorative Panel Assembly Process):

[0320] The plywood substrate is coated with urea-formaldehyde resin adhesive on both the top and bottom surfaces using a glue coating machine, with a coating amount of 170 g / m². 2 The plywood is then assembled by covering each plywood with decorative veneer, and then subjected to a pressing process. The pressing process includes placing the plywood in a cold press with a pressure of 0.1 MPa for 45 minutes, and then transferring it to a hot press with a temperature of 100℃ and a pressure of 1 MPa for 300 seconds. This yields the comparative plywood with layered flame-retardant decorative veneer.

[0321] test:

[0322] The prepared smoke-suppressing layered flame-retardant decorative veneer plywood of the control group was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0323] Oxygen index: 28.1%

[0324] Peak heat release rate: 296.11 kW / m 2

[0325] Total flue gas emission: 291.54 m³ 2 / m 2

[0326] Surface adhesive strength: 0.55 MPa

[0327] Comparative Example 2:

[0328] Preparation of materials:

[0329] 1. Wood veneer: 1.2mm thick poplar veneer

[0330] 2. Decorative veneer: 0.2mm thick poplar veneer

[0331] 3. Melamine-modified urea-formaldehyde resin

[0332] The solid content is 58%, and the melamine content is 10% (as a percentage of the total urea content);

[0333] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0334] 4. Flame retardant A

[0335] It was obtained by uniformly mixing CS-APP and soluble starch (purchased from Aladdin Biochemical Technology, with an active ingredient content of ≥99%) at a mass ratio of 1:0.3.

[0336] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0337] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added and stirred until homogeneous. The mixture was then filtered and dried to obtain powder 1. Powder 1 was then added to the saturated chitosan-acetic acid solution and stirred until homogeneous. This process was repeated 7 times to obtain chitosan-modified ammonium polyphosphate powder CS-APP, with a CS content of 6.8 wt% and an APP content of 93.2 wt%.

[0338] 5. Flour (industrial-grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0339] 6. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water to adjust the solid content to 58% before application, purchased from Guangzhou Yuanye Chemical).

[0340] preparation:

[0341] Step 1 (Preparation of flame-retardant adhesive):

[0342] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.2. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:15:6.

[0343] Step 2 (Plywood Substrate Assembly Process):

[0344] Take 5 sheets of wood veneer and assemble them into a plywood substrate according to the ordinary plywood assembly process. The ordinary plywood assembly process is as follows: apply urea-formaldehyde resin adhesive between each layer, with an adhesive application rate of 220g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The hot pressing pressure is 2 MPa, the hot pressing time is 45 min, and the hot pressing temperature is 120℃. The cold pressing pressure is 0.1 MPa, and the cold pressing time is 40 min.

[0345] Step 3 (Decorative Panel Assembly Process):

[0346] Flame-retardant adhesive is applied to the top and bottom surfaces of the plywood substrate using a gluing machine, with a coating amount of 170 g / m². 2 Each piece is then covered with a decorative veneer to form a blank, and then subjected to a pressing process. The pressing process includes: placing it in a cold press with a pressure of 0.1 MPa for 45 minutes, and then transferring it to a hot press with a temperature of 100℃ and a pressure of 1 MPa for 300 seconds, thereby obtaining the flame-retardant decorative veneer plywood of the comparison group.

[0347] test:

[0348] The prepared smoke-suppressing layered flame-retardant decorative veneer plywood of the control group was subjected to flame retardancy and mechanical tests, and the performance test results are as follows.

[0349] Oxygen index: 27.3%

[0350] Peak heat release rate: 288.74 kW / m 2

[0351] Total flue gas emission: 283.19m³ 2 / m 2

[0352] Surface adhesive strength: 0.57 MPa

[0353] Comparative Example 3

[0354] Preparation of materials:

[0355] 1. Wood veneer: 1.2mm thick poplar veneer

[0356] 2. Decorative veneer: 0.2mm thick poplar veneer

[0357] 3. Melamine-modified urea-formaldehyde resin

[0358] The solid content is 58%, and the melamine content is 10% (as a percentage of the total urea content);

[0359] It was prepared using the method described in Example 1 of patent CN200610059841.5.

[0360] 4. Flame retardant A

[0361] It was obtained by uniformly mixing CS-APP and soluble starch (purchased from Aladdin Biochemical Technology, with an active ingredient content of ≥99%) at a mass ratio of 1:0.3.

[0362] CS-APP is an intumescent flame retardant component, and its preparation method is as follows:

[0363] Chitosan (CS, degree of deacetylation ≥90%, purchased from Aladdin Biochemical Technology) was dissolved in 1000 mL of acetic acid until saturated. Then, an appropriate amount of ammonium polyphosphate (APP, analytical grade, purchased from Shandong Changsheng Flame Retardant New Materials) was added and stirred until homogeneous. The mixture was then filtered and dried to obtain powder 1. Powder 1 was then added to the saturated chitosan-acetic acid solution and stirred until homogeneous. This process was repeated 7 times to obtain chitosan-modified ammonium polyphosphate powder CS-APP, with a CS content of 6.8 wt% and an APP content of 93.2 wt%.

[0364] 5. Treatment solution 1

[0365] 0.75 mol / L tetrahydroxypropylethylenediamine aqueous solution (THPE aqueous solution)

[0366] 6. Treatment liquid 2

[0367] 0.50 mol / L phytic acid aqueous solution

[0368] 7. Flour (industrial grade wheat flour, purchased from Guangzhou Shenchuang Chemical)

[0369] 8. Urea-formaldehyde resin adhesive (water-soluble urea-formaldehyde resin powder, mixed with water before application to adjust the solid content to 58%, purchased from Guangzhou Yuanye Chemical).

[0370] preparation:

[0371] Step 1 (Flame-retardant impregnation treatment of veneer):

[0372] A certain number of wood veneers are placed in a vacuum pressure impregnation tank. Treatment solution 1 is injected directly into the impregnation tank (at normal pressure 0.2MPa) until it covers the wood veneers. The pressure is increased to 0.5MPa and maintained for 1 hour. Then, the pressure is reduced to normal pressure 0.2MPa and the treatment solution 1 is extracted. Treatment solution 2 is then injected directly into the impregnation tank (at normal pressure 0.2MPa). The pressure is increased to 0.5MPa and maintained for 1 hour. The wood veneers are then removed and placed in a forced-air drying oven to dry at 80℃ for 30 minutes to obtain flame-retardant veneers.

[0373] Step 2 (Preparation of flame-retardant adhesive):

[0374] Melamine-modified urea-formaldehyde resin and flame retardant A are added to an appropriate amount of water, stirred evenly, and left to stand for 1-2 hours until the pH value of the system is 7.2. Then flour is added and stirred evenly to obtain a flame-retardant adhesive. The mass ratio of melamine-modified urea-formaldehyde resin, flame retardant A and flour is 85:15:6.

[0375] Step 3 (Plywood substrate assembly process):

[0376] Two flame-retardant impregnated wood veneers were used as the top and bottom layers, and three untreated wood veneers were used as the core layer for assembly. A five-layer plywood substrate was prepared according to the ordinary plywood assembly process, wherein the ordinary plywood assembly process involves applying urea-formaldehyde resin adhesive between each layer at a coating amount of 220 g / m². 2 After assembly, the blanks are prepared by a pressing process, which includes cold pressing and hot pressing. The hot pressing pressure is 2 MPa, the hot pressing time is 45 min, and the hot pressing temperature is 120℃. The cold pressing pressure is 0.1 MPa, and the cold pressing time is 40 min.

[0377] Step 4 (Decorative Panel Assembly Process):

[0378] The plywood substrate is coated with urea-formaldehyde resin adhesive on both the top and bottom surfaces using a glue applicator, with a coating amount of 20 g / m². 2 After cold pressing at 0.1 MPa for 30 minutes, a further flame-retardant adhesive is applied to the flame-retardant adhesive, with an application amount of 170 g / m². 2 Each piece is then covered with a decorative veneer to form a blank, and then subjected to a pressing process. The pressing process includes: placing it in a cold press with a pressure of 0.1 MPa for 45 minutes, and then transferring it to a hot press with a temperature of 100℃ and a pressure of 1 MPa for 300 seconds, thereby obtaining the flame-retardant decorative veneer plywood of the comparison group.

[0379] test:

[0380] The flame-retardant decorative veneer plywood of the control group was subjected to flame-retardant and mechanical tests, and the performance test results are as follows.

[0381] Oxygen index: 30.7%

[0382] Peak heat release rate: 261.66 kW / m 2

[0383] Total flue gas emission: 266.94 m³ 2 / m 2

[0384] Surface bonding strength: 0.50 MPa.

Claims

1. A method for preparing a smoke-suppression type layered flame-retardant veneered plywood, the method comprising: impregnating wood veneers in a THPE aqueous solution with a concentration of 0.75-1.0 mol / L, pressurizing to 0.5-1.2 MPa and maintaining for 1-2 h, further impregnating the wood veneers in a phytic acid aqueous solution with a concentration of 0.5-0.65 mol / L, pressurizing to 0.5-1.0 MPa and maintaining for 1-2 h, and taking out the wood veneers to dry at a temperature of 75-80 ℃ for 30-60 min to obtain flame-retardant wood veneers; uniformly mixing melamine modified urea-formaldehyde resin and flame retardant A with an appropriate amount of water, placing the mixture to a system with a pH value of 7.2-7.5, and then adding flour to obtain a flame-retardant adhesive, wherein the mass ratio of melamine modified urea-formaldehyde resin, flame retardant A and flour is 85: (15-28) : (6-10), wherein the flame retardant A is a mixture composed of CS-APP and any one or combination of soluble starch, sucrose and glucose with a mass ratio of 1: (0.3-0.6), wherein the CS-APP is a mixture composed of chitosan and ammonium polyphosphate with a mass ratio of (1-7) : (94-99), and using the flame-retardant wood veneers as upper and lower surface veneers of the plywood to prepare a plywood substrate, applying the flame-retardant adhesive on the upper and lower surfaces of the plywood substrate, and then performing a pressing process after covering decorative wood veneers on the plywood substrate. characterized in that 2.The method of claim 1, wherein the decorative wood veneers are sliced solid wood veneers or reconstituted decorative veneers. 3.The method of claim 1, wherein the decorative wood veneers have a thickness of 0.2-0.4 mm. 4.The method of claim 1, wherein the preparation of the plywood substrate using the flame-retardant wood veneers as upper and lower surface veneers comprises: assembling the wood veneers, which have not been subjected to flame-retardant impregnation treatment, as core boards, applying adhesive between the boards, and then performing a pressing process. 5.The method of claim 4, wherein the adhesive applied in the preparation of the plywood substrate is urea-formaldehyde resin adhesive or phenol-formaldehyde resin adhesive. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The adhesive is applied by coating, with a coating amount of 200-220 g / m 2 ; ​ ​ ​ 6. The preparation method of claim 1, wherein, the pressing process comprises: placing the group of boards after being covered with the decorative wood veneer into a cold press with a pressure of 0.1-0.2 MPa for cold pressing for 35-45 min, and then transferring to a hot press with a temperature of 100-120 °C and a pressure of 1-1.5 MPa for hot pressing for 300-420 s. The fire-retardant adhesive is applied by coating, and the coating amount is 170-190 g / m 2 ; the veneered plywood is prepared by the preparation method of any one of claims 1-6.

7. A smoke-suppressing layered fire-retardant veneer-laminate characterized by ​

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