Flame-retardant PVC wood-plastic plate and preparation method thereof

Abstract

The invention discloses a flame-retardant PVC (polyvinyl chloride) wood-plastic plate which is prepared from the following raw materials in parts by weight: 100 parts of SG-7 type PVC resin; 20-30 parts of modified wood powder; the composite flame retardant is composed of ammonium polyphosphate, aluminum hydroxide, molybdenum trioxide and zinc borate according to the weight ratio of 15: 20: 16: 4; the mass ratio of the aluminum-titanium composite coupling agent to the wood flour is 1: 100; 5-8 parts of a calcium-zinc stabilizer; the lubricant is composed of polyethylene wax, paraffin and calcium stearate according to the weight ratio of 1: 1: 1; and 5-10 parts of an acetyl butyl citrate plasticizer. The invention relates to the technical field of polymer composite materials, in particular to a flame-retardant PVC wood-plastic plate and a preparation method thereof.The flame-retardant PVC wood-plastic plate and the preparation method thereof have the remarkable advantages that due to a composite flame retardant, the oxygen index of the plate reaches 32.1%, the combustion performance reaches the UL94V-0 level, and the smoke density is reduced by 72.1%; the tensile strength, the impact strength and the bending strength are respectively improved by 339.6%, 59.1% and 179.5% when the wood powder is treated by the aluminum-titanium coupling agent; the extrusion temperature of 150-175 DEG C and the screw rotating speed of 12-18 r / min are accurately controlled, the problems of wood powder carbonization and flame retardant decomposition are avoided, and the quality consistency is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer composite materials, in particular to a flame-retardant PVC wood-plastic board and a preparation method thereof. BACKGROUND

[0002] Traditional PVC wood-plastic boards have poor flame-retardant properties due to containing a large amount of plant fibers, and dense smoke and toxic gases are easily generated during combustion. The existing technology improves the flame-retardant properties by adding aluminum hydroxide, molybdenum trioxide and other flame retardants, but there is a problem of difficult balance between flame-retardant efficiency and mechanical properties. For example, a high filling amount (20-40 parts) of aluminum hydroxide is required to achieve a certain flame-retardant effect, but the tensile strength and impact strength of the board are significantly reduced. In addition, wood powder has poor compatibility with the PVC matrix, resulting in weak interfacial bonding force of the material, which further affects the comprehensive performance. Therefore, it is of great significance to develop a PVC wood-plastic board with high-efficiency flame-retardant and excellent mechanical properties. SUMMARY

[0003] Therefore, the embodiments of the present application aim to provide a flame-retardant PVC wood-plastic board and a preparation method thereof to solve or alleviate the technical problems in the prior art, and at least provide a beneficial choice.

[0004] The object of the present application can be achieved by the following technical measures:

[0005] A flame-retardant PVC wood-plastic board is made of the following raw materials by weight:

[0006] 100 parts of SG-7 type PVC resin

[0007] 20-30 parts of modified wood powder

[0008] 25-30 parts of composite flame retardant, composed of ammonium polyphosphate, aluminum hydroxide, molybdenum trioxide and zinc borate in a weight ratio of 15:20:16:4

[0009] 0.5-1 part of aluminum-titanium composite coupling agent, with a mass ratio of 1:100 to wood powder

[0010] 5-8 parts of calcium-zinc stabilizer

[0011] 3-5 parts of lubricant, composed of polyethylene wax, paraffin and calcium stearate in a weight ratio of 1:1:1

[0012] 5-10 parts of acetyl butyl citrate plasticizer.

[0013] The object of the present application can also be achieved by the following technical measures:

[0014] A preparation method of a flame-retardant PVC wood-plastic board, characterized in that it comprises the following steps:

[0015] Wood powder surface treatment: after wood powder is vacuum dried at 120 DEG C for 3 hours, the wood powder is mixed with 1% ethanol solution of aluminum-titanium composite coupling agent at a mass ratio of 100:1, stirred at 70 DEG C for 10 minutes, and then dried at 120 DEG C for 1 hour;

[0016] Premixing and plasticizing: the PVC resin, calcium-zinc stabilizer, lubricant and plasticizer are mixed at 100-110 DEG C for 5-10 minutes, and then the modified wood powder and the composite flame retardant are added after cooling to 65 DEG C and continue to mix for 5-8 minutes;

[0017] Extrusion molding: the temperature of the double-screw extruder is controlled as follows: the feeding section is at 145 DEG C, the compression section is at 160-180 DEG C, the metering section is at 170-180 DEG C, and the head is at 160-170 DEG C, the screw rotation speed is 12-18 r / min, and the traction speed is 1.1-1.2 m / min;

[0018] Cooling and shaping: the cooling water temperature of the vacuum shaping table is 5-10 DEG C, and the plate is cut into the required size.

[0019] The object of the application can also be achieved by the following technical measures:

[0020] In the composite flame retardant, the molybdenum trioxide and zinc borate form a ceramic layer, so that the smoke density grade of the plate is less than or equal to 72.1%.

[0021] The object of the application can also be achieved by the following technical measures:

[0022] The aluminum-titanium composite coupling agent is chemically bonded to the hydroxyl group on the surface of the wood powder, so that the tensile strength of the plate is increased to 44.4 MPa, and the impact strength is increased to 14.8 kJ / m 2 .

[0023] The object of the application can also be achieved by the following technical measures:

[0024] In the extrusion molding stage, the compression section temperature of 160-180 DEG C promotes the dehydration and carbonization reaction of ammonium polyphosphate and aluminum hydroxide, and the head temperature of 160-170 DEG C prevents the melt from foaming too early.

[0025] The object of the application can also be achieved by the following technical measures:

[0026] In the wood powder surface treatment step, the interface bonding force between the wood powder treated by the coupling agent and the PVC matrix is enhanced, and the interface bonding strength is increased by 59.1%.

[0027] The object of the application can also be achieved by the following technical measures:

[0028] The oxygen index of the plate is greater than or equal to 32.1%, the combustion performance reaches UL94 V-0 level when the thickness is 1.6 mm, and the tensile strength is greater than or equal to 44.4 MPa.

[0029] The object of the present application can also be achieved by the following technical measures:

[0030] The synergistic effect of the composite flame retardant makes the plate form a dense carbon layer when burning, and the carbon layer thickness is greater than or equal to 50 microns, and the scanning electron microscope image shows a continuous graphitization structure.

[0031] The object of the present application can also be achieved by the following technical measures:

[0032] The plate is suitable for fields with high fireproofing requirements such as building exterior walls, indoor decoration, furniture manufacturing, etc., and the dimensional stability error is less than or equal to 1.5% in an environment of -20 to 80 degrees Celsius.

[0033] The object of the present application can also be achieved by the following technical measures:

[0034] The method comprises the following steps: in the premixing stage, the temperature is controlled in a gradient from 100-110 degrees Celsius to 65 degrees Celsius, to ensure that the flame retardant is uniformly dispersed and does not decompose prematurely, and the dispersion degree of the flame retardant in the premix is greater than or equal to 95%.

[0035] The embodiment of the present application has the following advantages due to the use of the above technical solutions:

[0036] I. High-efficiency flame retardation: the composite flame retardant system (APP:ATH:MoO3:ZnB=15:20:16:4) makes the plate's oxygen index reach 32.1%, the combustion performance reaches UL94V-0 level (1.6mm), and the smoke density level (SDR) is reduced to 72.1%.

[0037] II. Excellent mechanical properties: after the wood powder is treated with an aluminum-titanium composite coupling agent, the plate's tensile strength is increased by 339.6%, the impact strength is increased by 59.1%, and the bending strength is increased by 179.5%.

[0038] III. Process stability: precise control of the extrusion temperature (150-175 degrees Celsius) and the screw rotation speed (12-18r / min) avoids incomplete carbonization of the wood powder and decomposition of the flame retardant, and ensures product quality consistency.

[0039] The above summary is only for the purpose of the description and is not intended to limit in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be apparent from the drawings and the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the accompanying drawings in the following description only only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained without creative labor on the basis of these drawings.

[0041] Figure 1 The raw material composition diagram of the present application is shown in the following table:

[0042] Figure 2 The preparation step diagram of the present application is shown in the following table:

[0043] Figure 3 The flame-retardant mechanism diagram of the present application is shown in the following table:

[0044] Figure 4 The performance index diagram of the present application is shown in the following table. DETAILED DESCRIPTION

[0045] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0046] It should be noted that the terms "first", "second", "symmetrical", "array" and the like are only used for distinguishing description and position description purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "symmetrical" and the like can explicitly or implicitly include one or more of the features; similarly, for some features that are not limited in number by the words "two", "three" and the like, it should be noted that the features also belong to explicitly or implicitly including one or more of the features.

[0047] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "fixing" and the like should be understood in a broad sense; for example, it can be fixed connection, or detachable connection, or one-piece; it can be mechanical connection, it can be direct connection, it can be welding, it can be indirect connection through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the description and drawings in combination with specific circumstances.

[0048] The embodiments of the present application will be described in detail below.

[0049] As shown in Figures 1-4 A flame-retardant PVC wood-plastic board is made from the following raw materials by weight:

[0050] SG-7 type PVC resin 100 parts

[0051] Modified wood powder 20-30 parts

[0052] Composite flame retardant 25-30 parts, composed of ammonium polyphosphate, aluminum hydroxide, molybdenum trioxide and zinc borate in a weight ratio of 15:20:16:4

[0053] Aluminum-titanium composite coupling agent 0.5-1 parts, mass ratio to wood powder 1:100

[0054] Calcium-zinc stabilizer 5-8 parts

[0055] Lubricant 3-5 parts, composed of polyethylene wax, paraffin wax and calcium stearate in a weight ratio of 1:1:1

[0056] Acetyl citrate butyl plasticizer 5-10 parts

[0057] In the composite flame retardant, molybdenum trioxide and zinc borate form a ceramic layer, so that the smoke density of the plate is ≤72.1%;

[0058] The aluminum-titanium composite coupling agent chemically bonds to the hydroxyl groups on the surface of the wood powder, so that the tensile strength of the plate is increased to 44.4 MPa, and the impact strength is increased to 14.8 kJ / m 2 ;

[0059] The oxygen index of the plate is ≥32.1%, the combustion performance reaches UL94V-0 level when the thickness is 1.6 mm, and the tensile strength is ≥44.4 MPa;

[0060] The synergistic effect of the composite flame retardant makes the plate form a dense carbon layer when burning, the carbon layer thickness is ≥50 μm, and the scanning electron microscope image shows a continuous graphitization structure;

[0061] The plate is suitable for high fireproofing requirements in fields such as building exterior walls, indoor decoration, furniture manufacturing, and has a dimensional stability error of ≤1.5% in an environment of -20℃ to 80℃;

[0062] The flame-retardant PVC wood-plastic plate in the present application has multiple significant advantages through scientific raw material ratio and performance optimization:

[0063] From the flame retardant performance, the ammonium polyphosphate, aluminum hydroxide, molybdenum trioxide and zinc borate in the composite flame retardant synergistically act in a specific ratio, which not only builds a double flame retardant barrier through chemical carbonization and physical cooling, but also effectively reduces the smoke density (≤72.1%) by forming a ceramic layer with molybdenum trioxide and zinc borate, and cooperates with the oxygen index ≥32.1% and the UL94V-0 level combustion performance, solves the pain points of insufficient flame retardancy and large amount of smoke of traditional wood-plastic plates, and meets the needs of high fireproofing scenes.

[0064] From the mechanical properties, the aluminum-titanium composite coupling agent improves the compatibility of wood powder and PVC matrix through chemical bonding, increases the tensile strength to 44.4 MPa, and the impact strength to 14.8 kJ / m 2 , breaks the contradiction of "high flame retardant filling and mechanical properties", and takes into account the flame retardant and structural strength.

[0065] From the stability and applicability, the size stability error of ≤1.5% (-20℃ to 80℃) ensures that there is no warping and cracking in extreme environment, and the compact graphitized carbon layer of more than 50μm further improves the durability of fire resistance, which is widely applicable to fields with high requirements for fireproof and durable such as building exterior wall and indoor decoration, and expands the application boundary of wood-plastic board.

[0066] A preparation method of a flame-retardant PVC wood-plastic board, comprising the following steps:

[0067] Wood powder surface treatment: after the wood powder is vacuum dried at 120℃ for 3 hours, it is mixed with 1% ethanol solution of aluminum-titanium composite coupling agent at a mass ratio of 100:1, stirred at 70℃ for 10 minutes, and then dried at 120℃ for 1 hour;

[0068] Premixing and plasticizing: PVC resin, calcium-zinc stabilizer, lubricant and plasticizer are mixed at 100-110℃ for 5-10 minutes, and then modified wood powder and composite flame retardant are added after cooling to 65℃, and the mixture is continuously mixed for 5-8 minutes;

[0069] Extrusion molding: the temperature of the double-screw extruder is controlled at 145℃ for feeding section, 160-180℃ for compression section, 170-180℃ for metering section, and 160-170℃ for head section, the screw rotation speed is 12-18r / min, and the traction speed is 1.1-1.2m / min;

[0070] Cooling and shaping: the cooling water temperature of the vacuum shaping table is 5-10℃, and the board is cut into the required size;

[0071] In the extrusion molding stage, the compression section temperature of 160-180℃ promotes the dehydration and carbonization reaction of ammonium polyphosphate and aluminum hydroxide, and the head temperature of 160-170℃ prevents the melt from foaming too early;

[0072] In the wood powder surface treatment step, the interface bonding force between the wood powder treated by the coupling agent and the PVC matrix is enhanced, and the interface bonding strength is increased by 59.1%;

[0073] The preparation method of the flame-retardant PVC wood-plastic board further comprises the following steps: in the premixing stage, the temperature is controlled at 100-110℃ and then decreased to 65℃, which ensures that the flame retardant is uniformly dispersed and does not decompose too early, and the dispersion degree of the flame retardant in the premixing material is ≥95%;

[0074] The preparation method of the flame-retardant PVC wood-plastic board in the application provides reliable guarantee for product performance through fine process design, and has outstanding advantages:

[0075] In terms of process accuracy, the "three-stage wood powder treatment" effectively reduces the moisture content of the wood powder and strengthens the interfacial bonding force (increases by 59.1%) through vacuum drying, coupling agent grafting and secondary drying, and avoids subsequent processing defects; the gradient temperature control premixing process (100-110°C decreases to 65°C) not only ensures uniform dispersion of the additives, but also prevents the decomposition of the flame retardant in advance, so that the dispersion degree of the flame retardant is ≥95%, and the performance of the raw materials is fully utilized.

[0076] In terms of process performance enhancement, the four-stage temperature gradient design of extrusion molding (feeding section to precise temperature control of the die head) not only promotes the synergistic reaction of ammonium polyphosphate and aluminum hydroxide to enhance the flame retardancy, but also prevents the melt from foaming through low temperature control of the die head, and cooperates with stable screw speed and pulling speed to ensure that the board surface is smooth and the structure is dense; low temperature control of cooling and setting locks the internal structure and reduces internal stress, finally realizes stable product performance, high batch consistency, and reduces the risk of quality fluctuation in the production process.

[0077] The following are several specific embodiments of the application

[0078] Example 1

[0079] Raw material formula (weight parts)

[0080] SG-7 type PVC resin: 100 parts

[0081] Modified wood powder: 20 parts

[0082] Composite flame retardant: 25 parts (ammonium polyphosphate: aluminum hydroxide: molybdenum trioxide: zinc borate = 15:20:16:4)

[0083] Aluminum-titanium composite coupling agent: 0.2 parts (mass ratio to wood powder 1:100)

[0084] Calcium-zinc stabilizer: 5 parts

[0085] Lubricant (polyethylene wax: paraffin wax: calcium stearate = 1:1:1): 3 parts

[0086] Acetyl citrate butyl ester plasticizer: 5 parts

[0087] Preparation process

[0088] Wood powder surface treatment: wood powder 120°C vacuum drying for 3 hours, 1% ethanol solution of aluminum-titanium composite coupling agent mixed at 100:1, 70°C stirring for 10 minutes, 120°C drying for 1 hour.

[0089] Premixing and plasticizing: PVC resin, calcium-zinc stabilizer, lubricant, plasticizer were mixed at 100℃ for 8 minutes, then modified wood powder and composite flame retardant were added after cooling to 65℃ and mixed for another 6 minutes.

[0090] Extrusion molding: the feeding section of the twin-screw extruder was at 145℃, the compression section was at 160℃, the metering section was at 170℃, the die head was at 160℃, the screw rotation speed was 12r / min, and the pulling speed was 1.1m / min.

[0091] Cooling and shaping: the cooling water temperature of the vacuum shaping table was 5℃, and the product was cut into a shape.

[0092] Performance test results

[0093] Oxygen index: 31.8%, combustion performance reached UL94 V-0 level (1.6mm)

[0094] Tensile strength: 42.6MPa, impact strength: 14.2kJ / m 2

[0095] Smoke density level: 73.5%, carbon layer thickness: 48μm

[0096] Dimensional stability error from -20℃ to 80℃: 1.4%

[0097] Advantages

[0098] This embodiment further optimizes the processing fluidity of the material while ensuring the core flame retardant performance (oxygen index ≥31%, V-0 level) by reducing the amount of wood powder and the total amount of flame retardant, which is suitable for producing thin-walled boards (such as 1.6mm decorative panels), and the dimensional stability still meets the use requirements in low temperature environment.

[0099] Example 2

[0100] Raw material formula (weight parts)

[0101] SG-7 type PVC resin: 100 parts

[0102] Modified wood powder: 30 parts

[0103] Composite flame retardant: 30 parts (ammonium polyphosphate: aluminum hydroxide: molybdenum trioxide: zinc borate = 15:20:16:4)

[0104] Aluminum-titanium composite coupling agent: 0.3 parts (mass ratio to wood powder 1:100)

[0105] Calcium-zinc stabilizer: 8 parts

[0106] Lubricant (polyethylene wax: paraffin wax: calcium stearate = 1:1:1): 5 parts

[0107] Acetyl citrate butyl plasticizer: 10 parts

[0108] Preparation process

[0109] Wood powder surface treatment: same as example 1, adjust the amount of coupling agent to 0.3 parts to match the high wood powder ratio.

[0110] Premixing and plasticizing: mix PVC resin and additives at 110℃ for 10 minutes, then add wood powder and flame retardant after cooling to 65℃, and mix for 8 minutes.

[0111] Extrusion molding: feeding section 145℃, compression section 180℃, metering section 180℃, head 170℃, screw speed 18r / min, pulling speed 1.2m / min.

[0112] Cooling and shaping: vacuum shaping table cooling water temperature 10℃, cut into shape.

[0113] Performance test results

[0114] Oxygen index: 33.5%, combustion performance reaches UL94 V-0 level (3.2mm)

[0115] Tensile strength: 45.1MPa, impact strength: 15.3kJ / m 2

[0116] Smoke density level: 71.2%, carbon layer thickness: 55μm

[0117] -20℃ to 80℃ dimensional stability error: 1.2%

[0118] Advantages

[0119] This example significantly improves the oxygen index and carbon layer thickness of the material by increasing the amount of wood powder, the total amount of flame retardant, and adjusting the high temperature parameters of extrusion, suitable for producing thick-walled load-bearing plates (such as 3.2mm floor base material), and the high coupling agent amount effectively offsets the interface defects brought by high wood powder, further enhancing the mechanical properties.

[0120] Example 3

[0121] Raw material formula (weight parts)

[0122] SG-7 type PVC resin: 100 parts

[0123] Modified wood powder: 22 parts

[0124] Composite flame retardant: 29 parts (ammonium polyphosphate: aluminum hydroxide: molybdenum trioxide: zinc borate = 15:18:18:4, increase the proportion of molybdenum trioxide)

[0125] Aluminum-titanium composite coupling agent: 0.22 parts (mass ratio to wood powder 1:100)

[0126] Calcium zinc stabilizer: 6 parts

[0127] Lubricant: 4 parts

[0128] Acetyl butyl citrate plasticizer: 7 parts

[0129] Preparation process

[0130] Wood powder treatment: extend the stirring time of coupling agent to 12 minutes, strengthen the surface coating.

[0131] Extruder head temperature: 165°C (slightly higher than the base value).

[0132] Performance test results

[0133] Oxygen index: 32.5%, combustion performance UL94 V-0 level (1.6mm)

[0134] Smoke density level: 69.8% (significantly lower than the base example of 72.1%)

[0135] Impact strength: 14.5kJ / m 2 , Tensile strength: 43.2MPa

[0136] Advantages

[0137] This embodiment further reduces the smoke density while maintaining the mechanical properties by increasing the proportion of molybdenum trioxide and extending the coupling agent treatment time, especially suitable for hospitals, schools and other places with strict low smoke requirements, verifying the optimization effect of fine-tuning of flame retardant components on smoke suppression performance.

[0138] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any skilled person in the art can easily think of various changes or replacements within the technical range disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A fire-retardant PVC wood plastic board, which is made of the following raw materials by weight: 100 parts of SG-7 PVC resin; 20-30 parts of modified wood powder; 25-30 parts of composite flame retardant, which is composed of ammonium polyphosphate, aluminum hydroxide, molybdenum trioxide and zinc borate in a weight ratio of 15:20:16:4; 0.5-1 part of aluminum-titanium composite coupling agent, with a mass ratio of 1:100 to wood powder; 5-8 parts of calcium-zinc stabilizer; 3-5 parts of lubricant, which is composed of polyethylene wax, paraffin wax and calcium stearate in a weight ratio of 1:1:1; 5-10 parts of acetyl butyl citrate plasticizer.

2. The preparation method of the flame-retardant PVC wood-plastic board according to claim 1, characterized in that, The steps include: Surface treatment of wood powder: after the wood powder is vacuum dried at 120℃ for 3 hours, it is mixed with 1% ethanol solution of aluminum-titanium composite coupling agent at a mass ratio of 100:1, stirred at 70℃ for 10 minutes, and then dried at 120℃ for 1 hour; Premixing and plasticizing: PVC resin, calcium-zinc stabilizer, lubricant and plasticizer are mixed at 100-110℃ for 5-10 minutes, and then modified wood powder and composite flame retardant are added after cooling to 65℃, followed by continuous mixing for 5-8 minutes; Extrusion molding: the temperature of the double-screw extruder is controlled as follows: feeding section 145℃, compression section 160-180℃, metering section 170-180℃, and die head 160-170℃, with a screw rotation speed of 12-18r / min and a pulling speed of 1.1-1.2m / min; Cooling and shaping: the cooling water temperature of the vacuum shaping table is 5-10℃, and the board is cut into the required size.

3. The flame-retardant PVC wood-plastic panel according to claim 1, characterized in that, In the composite flame retardant, molybdenum trioxide and zinc borate form a ceramic layer, which makes the smoke density grade of the board ≤72.1%.

4. The flame-retardant PVC wood-plastic panel according to claim 1, characterized in that, The aluminum-titanium composite coupling agent improves the plate tensile strength to 44.4 MPa and the impact strength to 14.8 kJ / m 2 .

5. The preparation method of the flame-retardant PVC wood-plastic board according to claim 2, characterized in that, During the extrusion molding stage, the temperature of the compression section (160-180℃) promotes the dehydration and carbonization reaction of ammonium polyphosphate and aluminum hydroxide, and the temperature of the die head (160-170℃) prevents the melt from foaming too early.

6. The preparation method of the flame-retardant PVC wood-plastic board according to claim 2, characterized in that, In the surface treatment step of the wood powder, the interface bonding force between the wood powder treated with the coupling agent and the PVC matrix is enhanced, and the interface bonding strength is increased by 59.1%.

7. The flame-retardant PVC wood-plastic panel according to claim 1, characterized in that, The oxygen index of the board is ≥32.1%, the combustion performance reaches UL94 V-0 level when the thickness is 1.6mm, and the tensile strength is ≥44.4MPa.

8. The flame-retardant PVC wood-plastic panel according to claim 1, characterized in that, The synergistic effect of the composite flame retardant makes the board form a dense carbon layer during combustion, with a carbon layer thickness ≥50μm and a continuous graphitization structure shown in the scanning electron microscope image.

9. The flame-retardant PVC wood-plastic panel according to claim 1, characterized in that, The board is suitable for fields with high fireproofing requirements, such as building exterior walls, indoor decoration and furniture manufacturing, and the dimensional stability error is ≤1.5% in an environment of -20℃ to 80℃.

10. The preparation method of the flame-retardant PVC wood-plastic board according to claim 2, characterized in that, The steps include: During the premixing stage, the temperature is controlled by gradient from 100-110℃ to 65℃, which ensures uniform dispersion of the flame retardant and prevents premature decomposition, and the dispersion degree of the flame retardant in the premixing material is ≥95%.

Images