Formaldehyde-free flame-retardant shaving board and preparation process thereof

Abstract

The invention provides a formaldehyde-free flame-retardant shaving board and a preparation process thereof. According to the method, the main material wood shavings of the shaving board are modified, boron is introduced, meanwhile, phosphorus-containing isocyanate and silicon-containing isocyanate are used as adhesives to replace traditional aldehyde adhesives, and three-dimensional network boron nitride is added, so that the prepared shaving board has the advantages of being low in formaldehyde emission and high in dry heat resistance, meanwhile, the smoke density grade is reduced, and the service life of the shaving board is prolonged. The limit oxygen index is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of artificial boards, and in particular relates to a formaldehyde-free flame-retardant particle board and a preparation process thereof. Background Art

[0002] Particleboard is a common type of man-made board, which is made from wood processing residues, logging residues, small diameter wood or wood plant fiber raw materials processed into shavings (or chips), and then pressed with adhesive. As a substitute for wood boards, particleboard improves the utilization rate of wood and eases the contradiction of wood shortage in my country. Particleboard products are currently widely used in custom furniture, kitchen and bathroom and architectural decoration, packaging, ships and vehicles.

[0003] The raw material of particleboard, wood, is an organic compound composed of carbon, hydrogen and oxygen elements. It is a combustible material, and its flammability can easily lead to fires. With the increasing number of buildings in cities, more and more particleboard materials are used in furniture production and building materials. The flammability of particleboard materials also poses a potential threat to people's lives and property, and at the same time greatly limits the application of particleboard in furniture and other aspects. Traditional particleboard production mainly uses formaldehyde-based adhesives represented by urea-formaldehyde resin, which have problems such as high formaldehyde emission, poor heat resistance, poor flame retardancy, and easy release of a lot of smoke when burning.

[0004] Therefore, how to achieve formaldehyde-free particleboard, increase the heat resistance of particleboard, improve flame retardancy, reduce smoke density level under combustion and decomposition conditions, and thus improve personal safety has become a focus area. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a formaldehyde-free flame-retardant particleboard and a preparation process thereof, aiming to solve the problems of traditional particleboard having high formaldehyde emission, poor heat resistance, poor flame retardant performance, and easy release of a large amount of thick smoke when burning.

[0006] The present invention introduces boron element by modifying the particle board's main material, wood particles, and uses phosphorus-containing isocyanate and silicon-containing isocyanate as adhesives to replace traditional aldehyde adhesives, and adds three-dimensional network boron nitride, so that the prepared particle board has low formaldehyde emission and high dry heat resistance, while reducing the smoke density level and improving the limiting oxygen index.

[0007] The technical solution of the present invention is as follows:

[0008] The first aspect of the present invention provides a process for preparing a formaldehyde-free flame-retardant particleboard, which is characterized by comprising the following preparation steps:

[0009] Step S1: weighing 60-70 parts of wood chips, 10-15 parts of adhesive, 2-5 parts of pentaerythritol and 5-10 parts of boron nitride;

[0010] Step S2: uniformly mixing the wood chips, adhesive, pentaerythritol and boron nitride in step S1 in a mixer, and paving the mixture to form a slab;

[0011] Step S3: sending the slab described in step S2 into a hot press to perform hot pressing and fixing forming to obtain a plate;

[0012] Step S4: cutting, cooling and sanding the board described in step S3 to prepare a formaldehyde-free flame-retardant particleboard.

[0013] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0014] As a preferred technical solution of the present invention, the wood shavings are boron-containing wood shavings; the preparation of the boron-containing wood shavings includes the following steps: 10 to 15 parts of wood shavings and 30 to 40 parts of hydrogen peroxide are mixed evenly, ultrasonically vibrated for 10 to 15 minutes, and then 5 to 8 parts of boric acid and 2 to 4 parts of ethyl orthosilicate are added, stirred evenly, and then put into a reactor, heated to 80°C, reacted for 90 minutes, and kept warm for 4 hours. After the insulation is completed, the material is cooled and collected to obtain the boron-containing wood shavings.

[0015] The boron element in the boron-containing wood chips decomposes when heated to produce boric anhydride or boric acid, forming a glassy melt that covers the surface of the particleboard, isolating the spread of oxygen and heat and suppressing the generation of thick smoke and molten droplets. In addition, the boron element in the wood chips combines with the phosphorus and silicon elements in the isocyanate to improve the flame retardant properties of the particleboard through the synergistic effect of boron, phosphorus and silicon.

[0016] As a preferred technical solution of the present invention, the adhesive is an isocyanate adhesive; the isocyanate adhesive is phosphorus-containing isocyanate and silicon-containing isocyanate; the mass ratio of the phosphorus-containing isocyanate to the silicon-containing isocyanate is 1:(0.5-1).

[0017] Preferably, the phosphorus-containing isocyanate is selected from any one or a combination of at least two of phosphorus-containing isocyanate I, phosphorus-containing isocyanate II and phosphorus-containing isocyanate III;

[0018] Wherein, the structural formula of the phosphorus-containing isocyanate I is:

[0019]

[0020] Wherein, the structural formula of the phosphorus-containing isocyanate II is:

[0021]

[0022] Wherein, the structural formula of the phosphorus-containing isocyanate III is:

[0023]

[0024] During combustion, the phosphorus-based groups in phosphorus-containing isocyanates will generate phosphaphenanthrene groups in the gas phase, which can capture the free radicals of the gas phase cracking gas, form a stable structure, and play a free radical quenching role; at the same time, the nitrogen-containing structure can also obtain a hindered amine structure with a quenching effect, forming a non-flammable gas, playing a gas phase dilution role. Phosphorus-nitrogen can cooperate with each other in the gas phase to effectively improve the flame retardant efficiency of particleboard. Phosphorus-containing isocyanates contain benzene ring structures, which have large intermolecular steric hindrance, large chemical bond energy, and good thermal stability of the material. The heat resistance is improved by introducing benzene rings into particleboard.

[0025] It should be noted that the source of phosphorus-containing isocyanate is not particularly limited in the present invention, and it can be purchased from the market or prepared by itself. The preparation method of phosphorus-containing isocyanate is not particularly limited in the present invention, and it can be prepared by referring to the method described in "Holtschmidt H, Oertel G. Isocyanates of Esters of Some Acids of Phosphorus and Silicion [J]. Angewandte Chemie International Edition, 2010, 1 (12): 617-621."

[0026] Preferably, the silicon-containing isocyanate is selected from any one or a combination of at least two of silicon-containing isocyanate I, silicon-containing isocyanate II and silicon-containing isocyanate III;

[0027] Wherein, the structural formula of the silicon-containing isocyanate I is:

[0028]

[0029] Wherein, the structural formula of the silicon-containing isocyanate II is:

[0030]

[0031] Wherein, the structural formula of the silicon-containing isocyanate III is:

[0032]

[0033] Under high temperature environment, silicon element has low surface energy and can easily migrate to the surface of particleboard to form silicon-containing protective layer, which improves the thermal stability of carbon layer on the surface of particleboard. Nitrogen element will produce flame-retardant nitrogen-containing compounds to dilute the concentration of combustion gas near the flame and play a flame retardant effect. The limiting oxygen index is increased through the synergistic effect of silicon and nitrogen. Silicon-containing isocyanate is composed of multiple benzene rings and has a rigid biphenyl structure, which can effectively increase the energy resistance of molecular chain segment conformational changes, reduce the diffusion movement of chain segments under high temperature conditions, and increase the heat resistance of particleboard.

[0034] It should be noted that the source of the silicon-containing isocyanate is not particularly limited in the present invention, and the isocyanate can be purchased from the market or prepared by itself. The preparation method of the silicon-containing isocyanate is not particularly limited in the present invention, and can be prepared by referring to the method described in "Holtschmidt H, Oertel G. Isocyanates of Esters of Some Acids of Phosphorus and Silicion [J]. Angewandte Chemie International Edition, 2010, 1 (12): 617-621."

[0035] As a preferred technical solution of the present invention, the boron nitride is a three-dimensional network boron nitride; the preparation of the three-dimensional network boron nitride includes the following steps: adding 5 to 10 parts of boron nitride to 25 to 50 parts of deionized water, and obtaining a boron nitride suspension by ultrasonic dispersion; adding 1 to 2 parts of 1,4-butanediol diglycidyl ether and 0.5 to 1 part of triethylenetetramine to 25 to 50 parts of deionized water, and magnetically stirring for 10 minutes to obtain a mixed solution; the boron nitride suspension and the mixed solution are uniformly mixed and magnetically stirred for 1 minute, poured into a mold, and placed in an environment of -70°C for 24 hours, freeze-dried at a temperature of -50°C and a pressure of 10Pa for 24 hours, and thermally cured at 150°C for 4 hours to obtain a three-dimensional network boron nitride.

[0036] The high thermal conductivity of the three-dimensional network boron nitride is conducive to the continuous transfer of high heat generated during combustion to the material away from the ignition point, avoiding excessive local temperature inside the material, and weakening the violent combustion caused by the rapid accumulation of a large amount of combustibles produced by the decomposition of local materials, thereby slowing down the spread of flames and increasing the limiting oxygen index; at the same time, the three-dimensional porous skeleton structure of boron nitride can also provide structural support for the carbon layer, making it easier for particleboard to form a heat-insulating and oxygen-isolating layer, thereby effectively reducing the diffusion of combustible gases into the flame area and reducing the smoke density level.

[0037] In a second aspect, the present invention provides a formaldehyde-free flame-retardant particleboard prepared by the method described in the first aspect.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The present invention uses phosphorus-containing isocyanate and silicon-containing isocyanate as adhesives, which can avoid formaldehyde generated by using aldehyde adhesives and achieve formaldehyde-free release; and because phosphorus-containing isocyanate and silicon-containing isocyanate are combined with boron-containing wood chips, boron, phosphorus and silicon have a synergistic flame retardant effect, thereby improving the limiting oxygen index without adding any additional flame retardant.

[0040] (2) The phosphorus-containing isocyanate and silicon-containing isocyanate used in the present invention contain rigid structures such as benzene rings, which can effectively increase the energy resistance of molecular chain segment conformational changes, reduce the diffusion movement of chain segments under high temperature conditions, and increase the heat resistance of particleboard. DETAILED DESCRIPTION

[0041] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0042] The sources of some components in the embodiments and comparative examples are as follows:

[0043] Wood shavings: corn straw shavings (purchased from Wanhua Jingzhou Company);

[0044] Adhesive: urea-formaldehyde resin adhesive (purchased from Zibo Huasen Adhesive Co., Ltd.);

[0045] Pentaerythritol: The CAS number of pentaerythritol is 115-77-5;

[0046] Flame retardant: The CAS number of melamine polyphosphate is 218768-84-4;

[0047] Preparation of boron-containing shavings: 10 parts of shavings (corn straw shavings, purchased from Wanhua Jingzhou Company) and 30 parts of hydrogen peroxide (CAS No. 7722-84-1) are mixed evenly, ultrasonically shaken for 10 to 15 minutes, and then 5 to 8 parts of boric acid (CAS No. 10043-35-3) and 2 to 4 parts of ethyl orthosilicate (CAS No. 78-10-4) are added, stirred evenly, and then put into a reactor, heated to 80°C, reacted for 90 minutes, and kept warm for 4 hours. After the insulation is completed, the material is cooled and collected to obtain the boron-containing shavings.

[0048] Preparation of three-dimensional network boron nitride: 5 parts of boron nitride (CAS No. 10043-11-5) are added to 25 parts of deionized water, and a boron nitride suspension is obtained by ultrasonic dispersion; 1 part of 1,4-butanediol diglycidyl ether (CAS No. 2425-79-8) and 0.5 parts of triethylenetetramine (CAS No. 112-24-3) are added to 25 parts of deionized water, and magnetic stirring is performed for 10 minutes to obtain a mixed solution; the boron nitride suspension and the mixed solution are uniformly mixed and magnetically stirred for 1 minute, poured into a mold, and placed in an environment of -70°C for 24 hours, freeze-dried at a temperature of -50°C and a pressure of 10Pa for 24 hours, and thermally cured at 150°C for 4 hours to obtain a three-dimensional network boron nitride.

[0049] Example 1

[0050] This embodiment provides a formaldehyde-free flame-retardant particleboard and a preparation process thereof, the preparation method comprising the following steps:

[0051] Step S1: weighing 60 parts of boron-containing wood shavings, 10 parts of phosphorus-containing isocyanate I, 5 parts of silicon-containing isocyanate III, 4 parts of pentaerythritol and 5 parts of three-dimensional network boron nitride;

[0052] Step S2: uniformly mixing the boron-containing wood shavings, phosphorus-containing isocyanate, silicon-containing isocyanate, pentaerythritol and three-dimensional network boron nitride described in step S1 in a mixer, and paving to form a slab;

[0053] Step S3: sending the slab described in step S2 into a hot press to obtain a plate by hot pressing and fixing the plate, wherein the hot pressing speed of the hot pressing section is 0.2 mm / s, the hot pressing temperature is 230° C., and the hot pressing plate surface pressure is 2.0 MPa;

[0054] Step S4: cutting, cooling and sanding the board described in step S3 to prepare a formaldehyde-free flame-retardant particleboard.

[0055] Example 2

[0056] This embodiment provides a formaldehyde-free flame-retardant particleboard and a preparation process thereof, the preparation method comprising the following steps:

[0057] Step S1: weighing 70 parts of boron-containing wood shavings, 5 parts of phosphorus-containing isocyanate II, 5 parts of silicon-containing isocyanate I, 5 parts of pentaerythritol and 10 parts of three-dimensional network boron nitride;

[0058] Step S2: uniformly mixing the boron-containing wood shavings, phosphorus-containing isocyanate, silicon-containing isocyanate, pentaerythritol and three-dimensional network boron nitride described in step S1 in a mixer, and paving to form a slab;

[0059] Step S3: sending the slab described in step S2 into a hot press to obtain a plate by hot pressing and fixing the plate, wherein the hot pressing speed of the hot pressing section is 0.1 mm / s, the hot pressing temperature is 160° C., and the hot pressing plate surface pressure is 1.0 MPa;

[0060] Step S4: cutting, cooling and sanding the board described in step S3 to prepare a formaldehyde-free flame-retardant particleboard.

[0061] Example 3

[0062] This embodiment provides a formaldehyde-free flame-retardant particleboard and a preparation process thereof, the preparation method comprising the following steps:

[0063] Step S1: weighing 65 parts of boron-containing wood shavings, 7 parts of phosphorus-containing isocyanate III, 5 parts of silicon-containing isocyanate II, 2 parts of pentaerythritol and 8 parts of three-dimensional network boron nitride;

[0064] Step S2: uniformly mixing the boron-containing wood shavings, phosphorus-containing isocyanate, silicon-containing isocyanate, pentaerythritol and three-dimensional network boron nitride described in step S1 in a mixer, and paving to form a slab;

[0065] Step S3: sending the slab described in step S2 into a hot press to obtain a plate by hot pressing and fixing the plate, wherein the hot pressing speed of the hot pressing section is 0.12 mm / s, the hot pressing temperature is 210° C., and the hot pressing plate surface pressure is 1.4 MPa;

[0066] Step S4: cutting, cooling and sanding the board described in step S3 to prepare a formaldehyde-free flame-retardant particleboard.

[0067] Example 4

[0068] This embodiment provides a formaldehyde-free flame-retardant particleboard and a preparation process thereof. The only difference from Embodiment 1 is that 65 parts of boron-containing particles are replaced with 60 parts of particles in this embodiment, and the rest is the same as Embodiment 1.

[0069] Example 5

[0070] This embodiment provides a formaldehyde-free flame-retardant particleboard and a preparation process thereof. The only difference from Embodiment 1 is that in this embodiment, 10 parts of phosphorus-containing isocyanate I and 5 parts of silicon-containing isocyanate III are replaced with 15 parts of urea-formaldehyde resin adhesive, and the rest is the same as Embodiment 1.

[0071] Example 6

[0072] This embodiment provides a formaldehyde-free flame-retardant particle board and a preparation process thereof. The only difference from Embodiment 1 is that this embodiment does not contain 5 parts of three-dimensional network boron nitride, and the rest is the same as Embodiment 1.

[0073] Comparative Example 1

[0074] This embodiment provides a particleboard and a preparation method thereof, the preparation method comprising the following steps:

[0075] Step S1: weighing 60 parts of wood chips, 15 parts of urea-formaldehyde resin adhesive and 4 parts of pentaerythritol;

[0076] Step S2: uniformly mixing the wood chips, urea-formaldehyde resin adhesive and pentaerythritol in step S1 in a mixer, and paving the mixture to form a slab;

[0077] Step S3: sending the slab described in step S2 into a hot press to obtain a plate by hot pressing and fixing the plate, wherein the hot pressing speed of the hot pressing section is 0.2 mm / s, the hot pressing temperature is 230° C., and the hot pressing plate surface pressure is 2.0 MPa;

[0078] Step S4: cutting, cooling and sanding the board described in step S3 to prepare a formaldehyde-free flame-retardant particleboard.

[0079] Comparative Example 2

[0080] This comparative example provides a particleboard and a preparation method thereof, which is different from comparative example 1 only in that 8 parts of melamine polyphosphate are added in this comparative example.

[0081] Comparative Example 3

[0082] This comparative example provides a particleboard and a preparation method thereof, and the only difference from comparative example 1 is that in this comparative example, 60 parts of wood chips are replaced with 60 parts of wood chips containing boron.

[0083] Comparative Example 4

[0084] This comparative example provides a particle board and a preparation method thereof, and the only difference from comparative example 1 is that in this comparative example, 15 parts of urea-formaldehyde resin adhesive are replaced by 10 parts of phosphorus-containing isocyanate I and silicon-containing isocyanate III.

[0085] Comparative Example 5

[0086] This comparative example provides a particle board and a preparation method thereof, and the only difference from comparative example 1 is that 5 parts of three-dimensional network boron nitride are added in this comparative example.

[0087] The particleboards provided in the above embodiments and comparative examples were tested, and the specific testing methods are as follows:

[0088] Formaldehyde emission: Tested in accordance with the requirements of GB 18580-2017 Limits of formaldehyde emission from artificial boards and their products for interior decoration and renovation materials.

[0089] Dry heat resistance: Tested with reference to the requirements of GB / T 17657-2022 Test methods for physical and chemical properties of wood-based panels and veneered wood-based panels; dry heat resistance is evaluated according to the following provisions to determine the level of surface change;

[0090] Level 5: No significant change;

[0091] Level 4: Slight changes in gloss and / or color when viewed from a certain angle;

[0092] Grade 3: Moderate changes in gloss and / or color;

[0093] Level 2: There is a noticeable change in gloss and / or color;

[0094] Level 1: Surface cracking and / or blistering.

[0095] Smoke density rating (SDR): Tested in accordance with the requirements of GB / T 8627-2007 Test method for smoke density of burning or decomposition of building materials.

[0096] Limiting oxygen index (LOI): Tested with reference to the requirements of GB / T 2406.2-2009 Plastics - Oxygen index method for combustion behavior - Part 2: Room temperature test.

[0097] The above performance test data is shown in Table 1:

[0098] Table 1

[0099]

[0100]

[0101] From the above content, it can be seen that the present invention introduces boron element by modifying the main material of particle board, using phosphorus-containing isocyanate and silicon-containing isocyanate as adhesives to replace traditional aldehyde adhesives, and adding three-dimensional network boron nitride, thereby preparing formaldehyde-free flame-retardant particle board (Examples 1 to 3), which has no detected formaldehyde emission, dry heat resistance reaches level five, smoke density grade (SDR) is 36.75~36.83, and limiting oxygen index (LOI) is 40.1~40.3.

[0102] Compared with Example 1, if boron-containing wood shavings are not used, the smoke density level increases and the limiting oxygen index decreases (Example 4); compared with Example 1, if phosphorus-containing isocyanate and silicon-containing isocyanate are not used, the dry heat resistance decreases, the limiting oxygen index decreases, and the formaldehyde emission reaches 0.32 mg / m3 (Example 5); compared with Example 1, if three-dimensional network boron nitride is not used, the limiting oxygen index decreases and the smoke density level increases (Example 6).

[0103] Comparative Example 1 does not adopt the technical innovation of the present invention, so the performance is poor, the formaldehyde emission is 0.33 mg / m3, the dry heat resistance is level four, the smoke density level is 46.14, and the limiting oxygen index is 31.4; compared with Comparative Example 1, if polyphosphate melamine flame retardant is added, the limiting oxygen index increases to 33.9 (Comparative Example 2); compared with Comparative Example 1, if boron-containing shavings are used, the smoke density level is reduced to 42.47 (Comparative Example 3); compared with Comparative Example 1, if phosphorus-containing isocyanate and silicon-containing isocyanate are used, no formaldehyde emission is detected, the dry heat resistance reaches level five, and the limiting oxygen index reaches 35.7 (Comparative Example 4); compared with Comparative Example 1, if 5 parts of three-dimensional network boron nitride are used, the smoke density level is reduced to 41.36, and the limiting oxygen index reaches 35.4 (Comparative Example 5).

[0104] In summary, the present invention introduces boron element by modifying the wood particles, the main material of the particle board, and uses phosphorus-containing isocyanate and silicon-containing isocyanate as adhesives to replace traditional aldehyde adhesives, and adds three-dimensional network boron nitride, so that the prepared particle board has low formaldehyde emission and high dry heat resistance, while reducing the smoke density level and improving the limiting oxygen index.

[0105] The applicant declares that the present invention illustrates the detailed process flow of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed process flow, that is, it does not mean that the present invention must rely on the above-mentioned detailed process flow to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A process for preparing formaldehyde-free flame-retardant particleboard, characterized in that: The preparation process includes the following steps: Step S1: weighing 60-70 parts of wood chips, 10-15 parts of adhesive, 2-5 parts of pentaerythritol and 5-10 parts of boron nitride; Step S2: uniformly mixing the wood chips, adhesive, pentaerythritol and boron nitride in step S1 in a mixer, and paving the mixture to form a slab; Step S3: sending the slab described in step S2 into a hot press to perform hot pressing and fixing forming to obtain a plate; Step S4: cutting, cooling and sanding the board described in step S3 to prepare a formaldehyde-free flame-retardant particleboard.

2. The process for preparing the formaldehyde-free flame-retardant particleboard according to claim 1, characterized in that: The wood shavings are boron-containing wood shavings.

3. The process for preparing the formaldehyde-free flame-retardant particleboard according to claim 2, characterized in that: The preparation of the boron-containing wood shavings comprises the following steps: 10 to 15 parts of wood shavings and 30 to 40 parts of hydrogen peroxide are mixed evenly, ultrasonically vibrated for 10 to 15 minutes, 5 to 8 parts of boric acid and 2 to 4 parts of ethyl orthosilicate are added, stirred evenly, and then put into a reactor, heated to 80° C., reacted for 90 minutes, kept warm for 4 hours, and after the end of the heat preservation, cooled and collected the output to obtain the boron-containing wood shavings.

4. The process for preparing the formaldehyde-free flame-retardant particleboard according to claim 1, characterized in that: The adhesive is an isocyanate adhesive.

5. The process for preparing the formaldehyde-free flame-retardant particleboard according to claim 4, characterized in that: The isocyanate adhesive is phosphorus-containing isocyanate and silicon-containing isocyanate; the mass ratio of the phosphorus-containing isocyanate to the silicon-containing isocyanate is 1:(0.5-1).

6. The process for preparing the formaldehyde-free flame-retardant particleboard according to claim 5, characterized in that: The phosphorus-containing isocyanate is selected from any one or a combination of at least two of phosphorus-containing isocyanate I, phosphorus-containing isocyanate II and phosphorus-containing isocyanate III; Wherein, the structural formula of the phosphorus-containing isocyanate I is: Wherein, the structural formula of the phosphorus-containing isocyanate II is: Wherein, the structural formula of the phosphorus-containing isocyanate III is:

7. The process for preparing the formaldehyde-free flame-retardant particleboard according to claim 5, characterized in that: The silicon-containing isocyanate is selected from any one or a combination of at least two of silicon-containing isocyanate I, silicon-containing isocyanate II and silicon-containing isocyanate III; Wherein, the structural formula of the silicon-containing isocyanate I is: Wherein, the structural formula of the silicon-containing isocyanate II is: Wherein, the structural formula of the silicon-containing isocyanate III is:

8. The process for preparing formaldehyde-free flame-retardant particleboard according to claim 1, characterized in that: The boron nitride is a three-dimensional network boron nitride.

9. The process for preparing the formaldehyde-free flame-retardant particleboard according to claim 8, characterized in that: The preparation of the three-dimensional network boron nitride includes the following steps: adding 5 to 10 parts of boron nitride to 25 to 50 parts of deionized water, dispersing by ultrasonic to obtain a boron nitride suspension; adding 1 to 2 parts of 1,4-butanediol diglycidyl ether and 0.5 to 1 part of triethylenetetramine to 25 to 50 parts of deionized water, and magnetically stirring for 10 minutes to obtain a mixed solution; the boron nitride suspension and the mixed solution are uniformly mixed and magnetically stirred for 1 minute, poured into a mold, placed in an environment of -70°C for 24 hours, freeze-dried at a temperature of -50°C and a pressure of 10Pa for 24 hours, and thermally cured at 150°C for 4 hours to obtain a three-dimensional network boron nitride.

10. A formaldehyde-free flame-retardant particleboard prepared according to the method of any one of claims 1 to 9.

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