Flame-retardant anti-static anti-explosion air pipe and preparation method thereof

Abstract

The invention discloses a preparation method of a flame-retardant, antistatic and anti-explosion air pipe, the air pipe adopts PVC (polyvinyl chloride) paste resin as a matrix, a reinforcing layer is glass fiber or basalt fiber, and a multi-layer structure is formed by combining a dip coating or lamination composite process with a PVC layer; the preparation method comprises the following steps: a, preparing a PVC paste resin matrix material, wherein the PVC paste resin matrix material is prepared from the following raw materials in parts by weight: 27 to 54 parts of PVC paste resin, 10 to 20 parts of PVC blended resin, 25.5 to 30.5 parts of plasticizer, 2.1 to 2.3 parts of rapeseed oil, 0.59 to 0.89 part of calcium-zinc stabilizer, 3 to 10 parts of antistatic agent and 20 to 50 parts of flame retardant; b, combining the reinforcing layer with the matrix by adopting a dipping or coating process; and c, processing and forming by adopting a winding process. According to the invention, the PVC paste resin is used as a matrix, the reinforcing layer is made of glass fibers or basalt fibers, and the flame retardant and the antistatic agent are added, so that the flame retardance and the antistatic property of the air duct can be improved. And meanwhile, other raw materials are added and reasonably blended, so that the air pipe disclosed by the invention also has good anti-knock performance.

Description

Technical Field

[0001] The present invention relates to a duct and a preparation method thereof, in particular to a flame-retardant, antistatic and explosion-proof duct and a preparation method thereof. Background Art

[0002] At present, ducts are widely used for ventilation in fields such as coal mines, chemical industries, tunnels and underground projects. Especially at the connection between the ventilation duct and the fan, on the one hand, the wind pressure is high, and on the other hand, the fan vibrates greatly, so the requirements for the duct are further improved. The traditional ducts have the following problems:

[0003] Lack of flame retardancy: Some plastic ducts are flammable, posing a fire hazard.

[0004] Insufficient antistatic performance: It is easy to cause sparks due to static electricity accumulation, posing a safety hazard.

[0005] Poor impact resistance and explosion-proof performance: Traditional ducts mostly use hard materials for toughening or use air duct cloth with a flame-retardant and antistatic layer coated as a flame-retardant and antistatic duct. The explosion-proof duct is easy to rupture under the impact of high-pressure air flow or explosion.

[0006] Patent CN111320828A introduces a nano flame-retardant and antistatic air duct cloth and a preparation method thereof. This scheme uses a nano flame-retardant coating to prepare an air duct cloth. The air duct cloth prepared by this method is thinner and has poor compressive performance; Patent CN102786754B - a flame-retardant, antistatic and toughened PVC pipe for biogas uses rigid PVC as the base material and achieves explosion-proof performance through toughening. The pipes prepared by this method have good actual use performance, but are easily damaged at the connection between the fan and the pipe due to large vibrations. Summary of the Invention

[0007] The purpose of the present invention is to provide a flame-retardant, antistatic and explosion-proof duct and a preparation method thereof. The duct of the present invention has the functions of flame retardancy, antistatic and explosion proof, so as to improve its safety and durability.

[0008] The technical solution of the present invention: A preparation method of a flame-retardant, antistatic and explosion-proof duct, the duct uses PVC paste resin as the matrix, the reinforcing layer is glass fiber or basalt fiber, and a multi-layer structure is formed by combining with a PVC layer through an impregnation coating or lamination composite process; the preparation method includes the following steps:

[0009] a: Prepare the PVC paste resin matrix material: The PVC paste resin matrix material is composed of the following raw materials in parts by weight:

[0010] 27 - 54 parts of PVC paste resin, 10 - 20 parts of PVC blending resin, 25.5 - 30.5 parts of plasticizer, 2.1 - 2.3 parts of rapeseed oil, 0.59 - 0.89 parts of calcium-zinc stabilizer, 3 - 10 parts of antistatic agent, 20 - 50 parts of flame retardant;

[0011] b: The reinforcing layer is combined with the matrix by using an impregnation or coating process;

[0012] c: The winding process is used for processing and forming.

[0013] In the preparation method of the above-mentioned flame-retardant, antistatic and explosion-proof air duct, in the step a, the specific method for preparing the PVC paste resin matrix material is as follows:

[0014] First, dry the antistatic agent, flame retardant, calcium-zinc stabilizer, PVC paste resin, and PVC blending resin in an environment of 40°C for 2 hours. Take the plasticizer and divide it into two parts by mass fraction, one part is 90% and the other part is 10%. First, stir 90% of the plasticizer at 200 revolutions per minute for 0.5 minutes, and add the calcium-zinc stabilizer while stirring. Then, stir at 1000 revolutions per minute for 5 minutes. After the small materials are mixed evenly, adjust the stirring speed to 200 revolutions per minute, and then slowly add the PVC paste resin and PVC blending resin. After adding, continue to stir at 200 revolutions per minute for 5 minutes. Then, adjust the rotation speed to 1000 revolutions per minute and stir for 10 minutes. After all the powder materials are stirred evenly, adjust the rotation speed to 200 revolutions per minute, add the remaining 10% of the plasticizer and rapeseed oil, and then stir at 1000 revolutions per minute for 15 minutes. During the stirring process, control the temperature of the whole system to be kept below 40°C, and then filter with a 120-mesh sieve to make a colloid with an automatic viscosity of 1200 ± 100 mPa·s, that is, the PVC paste resin matrix material is obtained.

[0015] In the preparation method of the above-mentioned flame-retardant, antistatic and explosion-proof air duct, the winding process for processing and forming in the step c is specifically as follows: The winding pipe body mold rotates along the main axis. The mold uses a variable inner diameter mold, and its structure is that the outside uses stainless steel with a large deformation amount as the support body, and the inside uses steel wire as the support body. A heating tube and a sensor are connected to the outside of the support body. The heating tube is heated and cured at 200 - 230°C, and the power supply is connected to the outside through a rotary joint.

[0016] In the preparation method of the above-mentioned flame-retardant, antistatic and explosion-proof air duct, the antistatic agent is selected from conductive carbon black, carbon nanotubes or metal fibers.

[0017] In the preparation method of the above-mentioned flame-retardant, antistatic and explosion-proof air duct, the flame retardant is selected from phosphorus-nitrogen based flame retardants, antimony trioxide or aluminum hydroxide.

[0018] In the preparation method of the above-mentioned flame-retardant, antistatic and explosion-proof air duct, the flame retardant is aluminum hydroxide, and its particle size is less than 10 μm.

[0019] In the preparation method of the above-mentioned flame-retardant, antistatic and explosion-proof air duct, the plasticizer is tributyl acetylcitrate plasticizer or DINCH.

[0020] An air duct prepared by a preparation method of a flame-retardant, antistatic and explosion-proof air duct.

[0021] Advantages of the present invention: Compared with the prior art, the present invention adopts the above technical solution. By using PVC paste resin as the matrix, the reinforcing layer is glass fiber or basalt fiber, and a flame retardant and an antistatic agent are added, so that the flame retardancy and antistatic performance of the air duct can be improved, and the surface resistance of the air duct is lower than 10 6 Ω, and the air duct reaches the UL94 V-0 flame retardant grade. At the same time, by adding other raw materials and reasonably adjusting the materials used among them, the air duct of the present invention also has good tensile strength, impact strength and pressure resistance. The flame-retardant, antistatic and explosion-proof air duct of the present invention has good flame retardancy, antistatic and flexible explosion-proof capabilities, and can be widely used in the field of coal mining. Description of the drawings

[0022] Figure 1 Schematic diagram of the flame retardant performance when a common flame retardant is used alone;

[0023] Figure 2 Schematic diagram of the influence of the dosage of aluminum hydroxide on the flame retardant performance and mechanical properties of the system;

[0024] Figure 3 Schematic diagram of the influence of the particle size of aluminum hydroxide on the flame retardant performance and mechanical properties of the system. Detailed implementation manners

[0025] The following further illustrates the present invention in conjunction with embodiments, but it is not used as a basis for limiting the present invention.

[0026] Embodiment 1 of the present invention:

[0027] Raw materials: 89.6 kg of PVC paste resin (polymerization degree 1200), 33.6 kg of PVC blending resin, 70 kg of tributyl acetate-citric acid plasticizer, 5.32 kg of rapeseed oil, 12 kg of antistatic agent conductive carbon black, 30 kg of flame retardant phosphorus-nitrogen based flame retardant, 1.96 kg of calcium-zinc stabilizer.

[0028] Preparation method: First, dry the antistatic agent, flame retardant, calcium-zinc stabilizer, PVC paste resin, and PVC blending resin in an environment at 40°C for 2 hours. Take tributyl acetylcitrate plasticizer and divide it into two parts by mass fraction. One part is 63 kg and the other part is 7 kg. First, stir 63 kg of the plasticizer at 200 revolutions per minute for 0.5 minutes. While stirring, add the antistatic agent, flame retardant, and calcium-zinc stabilizer. Then stir at 1000 revolutions per minute for 5 minutes. After the small ingredients are mixed evenly, adjust the stirring speed to 200 revolutions per minute, and slowly add the PVC paste resin and PVC blending resin. After adding, continue to stir at 200 revolutions per minute for 5 minutes. Then adjust the rotation speed to 1000 revolutions per minute and stir for 10 minutes. After all the powder materials are stirred evenly, adjust the rotation speed to 200 revolutions per minute, add the remaining 7 kg of plasticizer and rapeseed oil, and then stir at high speed at 1000 revolutions per minute for 15 minutes to obtain the product. First, the fiber is infiltrated through the PVC paste resin and wound linearly around the core mold and cured by heating at 230°C to fully crosslink the material and improve the mechanical properties. Finally, demolding can obtain the explosion-proof air duct.

[0029] Example 2 of the present invention:

[0030] Raw materials: 80 kg of PVC paste resin (polymerization degree 1200), 20 kg of PVC blending resin, 65 kg of dioctyl terephthalate plasticizer, 15 kg of carbon nanotubes, 20 kg of antimony trioxide, 4 kg of rapeseed oil, 1.9 kg of calcium-zinc stabilizer,

[0031] Preparation method: First, dry the antistatic agent, flame retardant, calcium-zinc stabilizer, PVC paste resin, and PVC blending resin in an environment at 40°C for 2 hours. Take tributyl acetylcitrate plasticizer and divide it into two parts by mass fraction. One part is 90% and the other part is 10% g. First, stir 90% of the plasticizer at 250 revolutions per minute for 1 minute. While stirring, add the antistatic agent, flame retardant, and calcium-zinc stabilizer. Then stir at 1000 revolutions per minute for 3 minutes. After the small ingredients are mixed evenly, adjust the stirring speed to 200 revolutions per minute, and slowly add the PVC paste resin and PVC blending resin. After adding, continue to stir at 200 revolutions per minute for 5 minutes. Then adjust the rotation speed to 1000 revolutions per minute and stir for 10 minutes. After all the powder materials are stirred evenly, adjust the rotation speed to 200 revolutions per minute, add the remaining 10% of the plasticizer and rapeseed oil, and then stir at high speed at 1000 revolutions per minute for 15 minutes to obtain the product. First, the fiber is infiltrated through the PVC paste resin and wound linearly around the core mold and cured by heating at 220°C to fully crosslink the material and improve the mechanical properties. Finally, demolding can obtain the explosion-proof air duct.

[0032] Example 3 of the present invention:

[0033] Raw materials: 70 kg of PVC paste resin (degree of polymerization 1200), 30 kg of PVC blending resin, 60 kg of DINCH, 4.5 kg of rapeseed oil, 13.9 kg of metal fiber, 1.7 kg of calcium-zinc stabilizer, 20 kg of aluminum hydroxide

[0034] Preparation method: First, dry the antistatic agent, flame retardant, calcium-zinc stabilizer, PVC paste resin, and PVC blending resin at 40 °C for 2 hours. Take DINCH and divide it into two parts by mass fraction, one part is 80% and the other part is 20% g. First, stir 80% of the plasticizer at 200 revolutions per minute for 1 minute, and add the antistatic agent, flame retardant, and calcium-zinc stabilizer while stirring. Then stir at 1000 revolutions per minute for 3 minutes. After the small materials are mixed evenly, adjust the stirring speed to 250 revolutions per minute, and then slowly add the PVC paste resin and PVC blending resin (it needs to be added slowly and wait until the powder is infiltrated before adding more). After adding, continue to stir at 250 revolutions per minute for 6 minutes, then adjust the rotation speed to 1000 revolutions per minute and stir for 15 minutes. After all the powder materials are stirred evenly, adjust the rotation speed to 200 revolutions per minute, add the remaining 20% of the plasticizer and rapeseed oil, and then stir at high speed at 1000 revolutions per minute for 15 minutes to obtain. First, the fiber is infiltrated through the PVC paste resin and wound linearly around the core mold and cured by heating at 200 °C to fully crosslink the material and improve the mechanical properties. Finally, demold to obtain the explosion-proof air duct.

[0035] The air ducts prepared in the above examples were tested, and their performance is shown in Table 1.

[0036] Table 1

[0037] Index Example 1 Example 2 Example 3 Flame retardant grade UL94V-0 UL94V-0 UL94V-0 Surface resistance <![CDATA[1.0×10 6 Ω]]> <![CDATA[1.0×10 5 Ω]]> <![CDATA[1.0×10 5 Ω]]> Tensile strength 15MPa 18MPa 14MPa Impact strength <![CDATA[30KJ / m 2 > <![CDATA[32KJ / m 2 > <![CDATA[28KJ / m 2 > Voltage withstand capacity 1.5MPa 2.0MPa 1.8MPa

[0038] Since static electricity will be generated when gas flows in the air duct, excessive static electricity accumulation may lead to serious accidents such as fires or explosions. Increasing the addition of antistatic agents can effectively avoid excessive static electricity accumulation and reduce the risk of fires or explosions. According to the regulations of AQ1071-2009 "Safety Technical Requirements for Non-metallic Gas Transmission Pipes for Coal Mines", the resistance value ≤ 1×10 6 can meet the antistatic requirements.

[0039] Among them, taking conductive carbon black as an example, conductive carbon black is an inorganic compound with good electrical conductivity, which can effectively eliminate or reduce static electricity accumulation, reduce the risk of fires or explosions, has good chemical stability, will not decompose due to moisture or heat, does not produce harmful gases, and will not cause harm to the environment and human body. Based on the advantages of conductive carbon black as an antistatic agent, conductive carbon black is added as an antistatic agent to the resin-based fiber composite material. The resistance change is shown in Table 2 below. Based on this test, the dosage of the antistatic agent was confirmed.

[0040] Table 2

[0041] Acetylene black / % Resistance value / Ω 0 <![CDATA[10 12.1 > 0.6 <![CDATA[10 11.5 > 0.8 <![CDATA[10 11.4 > 1.0 <![CDATA[10 11.4 > 1.2 <![CDATA[10 11.3 > 1.5 <![CDATA[10 10.0 > 2.0 <![CDATA[10 9.6 > 3.0 <![CDATA[10 6.7 > 4.0 <![CDATA[10 5.5 >

[0042] Combined with the action mechanism of the flame retardant, that is, how to terminate the chain reaction of the free radical HO0 generated by combustion, based on the flame retardant mechanism, the commonly used flame retardants such as aluminum hydroxide, antimony trioxide, and decabromodiphenyl ether were optimized, and the results are shown in Figure 1 。

[0043] From Figure 1 it can be seen that by adding the organic halogen-containing flame retardant decabromodiphenyl ether and utilizing the flame retardant effect of halogen, the combustible can be self-extinguished, and the more the addition amount, the more obvious the flame retardant effect. Due to the generation of HX, the pungent smell is strong during curing, which affects the operating environment. Antimony trioxide is a relatively good variety among inorganic flame retardants. From Figure 1 it can be seen that the more the addition amount, the better the flame retardancy, but the cost performance is relatively low, and the industrial application cost is relatively high. Inorganic Al(OH)3 is a relatively good flame retardant material. Aluminum hydroxide can quickly absorb heat, release water and oxygen, and form aluminum oxide, thereby reducing the combustion temperature and calorific value of the substance and achieving the flame retardant effect. At the same time, aluminum hydroxide has good chemical stability, is not easy to decompose, does not produce harmful gases, does not harm the environment and human body, and the price is relatively moderate. Therefore, aluminum hydroxide can be preferentially selected as the flame retardant.

[0044] Based on the advantages of aluminum hydroxide, using the paste resin material as the matrix and aluminum hydroxide as the flame retardant filler, the experimental results of studying the effects of the content and particle size of aluminum hydroxide on the flame retardancy and mechanical properties of the system are shown in Table 3, Figure 2 、 Figure 3 。The results show that when the mass fraction of added aluminum hydroxide is greater than 40%, the flame retardant performance of the system is significantly improved; when the mass fraction of aluminum hydroxide is 60%, the limiting oxygen index of the material is 34.3%, and the vertical burning test reaches the highest flame retardant level V-0; the impact strength increases with the increase of the content of aluminum hydroxide, and the flexural strength reaches the maximum when the mass fraction of aluminum hydroxide is 40%. The particle size of aluminum hydroxide has a greater impact on the flame retardancy and mechanical properties of the unsaturated resin-aluminum hydroxide system. After the superfine refinement of aluminum hydroxide, the flexural strength, impact strength, and oxygen index of the system are all greatly increased; the thermal mass loss rate of the material is significantly smaller than that of pure unsaturated resin, and the residual carbon content is significantly increased. When the particle size of aluminum hydroxide is greater than 10 μm, the influence on the flame retardant performance of the filler is not obvious; when the particle size is less than 10 μm, the flame retardant performance is significantly improved. When the flame retardants are of equal amount, the smaller the particle size, the larger the specific surface area, and the better the flame retardant effect. With the decrease of the particle size, the flexural strength and impact strength of the blend material system increase continuously.

[0045] Table 3 Relationship between the content and particle size of aluminum hydroxide and the vertical burning grade

[0046] Aluminum oxide content (%) Vertical combustion grade Aluminum oxide particle size (μm) Vertical combustion grade 0 --- 22.21 V-0 10 Did not reach V-1 17.22 V-0 20 Did not reach V-1 12.66 V-0 30 Did not reach V-1 6.57 V-0 40 V-0 50 V-0 60 V-0

Claims

1. A method for preparing a flame retardant, antistatic and explosion-resistant air duct, characterized in that: The air duct uses PVC paste resin as a matrix, and the reinforcement layer is glass fiber or basalt fiber, and the PVC layer is combined by an impregnation coating or lamination composite process to form a multi-layer structure; the preparation method includes the following steps: a: Preparation of PVC paste resin matrix material: The PVC paste resin matrix material is composed of the following raw materials in parts by weight: 27-54 parts of PVC paste resin, 10-20 parts of PVC blended resin, 25.5-30.5 parts of plasticizer, 2.1-2.3 parts of rapeseed oil, 0.59-0.89 parts of calcium-zinc stabilizer, 3-10 parts of antistatic agent, 20-50 parts of flame retardant; b: Use impregnation or coating process to combine the reinforcement layer with the substrate; c: It is processed by winding technology.

2. The method for preparing a flame-retardant, antistatic and explosion-resistant air duct according to claim 1, characterized in that: In the step a, the specific method for preparing the PVC paste resin matrix material is: First, dry the antistatic agent, flame retardant, calcium-zinc stabilizer, PVC paste resin, and PVC blended resin at 40°C for 2 hours, take the plasticizer and divide it into 2 parts by mass, one part is 90% and the other part is 10%, first stir the 90% plasticizer at 200 rpm for 0.5 minutes, add the calcium-zinc stabilizer while stirring, then stir at 1000 rpm for 5 minutes, adjust the stirring speed to 200 rpm after the small materials are evenly mixed, and then slowly add the PVC paste resin, PVC blended resin, and the mixture. After the fat is added, continue stirring at 200 rpm for 5 minutes, then adjust the speed to 1000 rpm and stir for 10 minutes. After the powder material is completely stirred, adjust the speed to 200 rpm, add the remaining 10% of plasticizer and rapeseed oil, and then stir at 1000 rpm for 15 minutes. During the stirring process, control the temperature of the entire system to be kept below 40°C, and then filter with a 120-mesh screen to produce a colloid with an automatic viscosity of 1200±100mpa.s, that is, a PVC paste resin matrix material.

3. The method for preparing a flame-retardant, antistatic and explosion-resistant air duct according to claim 1, characterized in that: The winding process of step c is specifically as follows: the winding tube body mold rotates along the main axis, the mold adopts a variable inner diameter mold, and its structure is that stainless steel with a large deformation amount is used as the support body on the outside, and steel wire is used as the support body on the inside. The outside of the support body is connected to a heating tube and a sensor heating tube, which is heated and cured at 200-230°C, and the power supply is connected to the outside through a rotating joint.

4. The method for preparing a flame-retardant, antistatic and explosion-resistant air duct according to claim 1, characterized in that: The antistatic agent is selected from conductive carbon black, carbon nanotubes or metal fibers.

5. The method for preparing a flame-retardant, anti-static and explosion-resistant air duct according to claim 1, characterized in that: The flame retardant is selected from phosphorus-nitrogen flame retardants, antimony trioxide or aluminum hydroxide.

6. The method for preparing a flame-retardant, anti-static and explosion-resistant air duct according to claim 5, characterized in that: The flame retardant is aluminum hydroxide, and the particle size thereof is less than 10 μm.

7. The method for preparing a flame-retardant, anti-static and explosion-resistant air duct according to claim 1, characterized in that: The plasticizer is tributyl acetate citrate plasticizer or DINCH.

8. An air duct prepared by the method for preparing a flame-retardant, antistatic and explosion-resistant air duct as claimed in any one of claims 1 to 7.

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