High-performance polyethylene fireproof coating and preparation method thereof

Abstract

The invention relates to the technical field of coatings, in particular to a high-performance polyethylene fireproof coating and a preparation method thereof. Comprising the following raw materials in parts by weight: 50-70 parts of polyethylene resin, 10-20 parts of hydrated zinc borate, 15-25 parts of flame-retardant expanded vermiculite powder, 5-10 parts of nano ceramic microspheres, 3-8 parts of silane modified glass fibers, 5-10 parts of a flame-retardant plasticizer, 2-5 parts of a surface treating agent and 1-3 parts of a dispersing agent. According to the invention, the silane modified glass fiber and the polyethylene resin form a hydrophobic network through surface chemical bonding to block a moisture permeation path, the surface treating agent further optimizes the surface energy of the coating and reduces the interaction between polar groups and water molecules, and the silane modified glass fiber and the polyethylene resin synergistically construct a stable hydrophobic barrier to greatly reduce the water absorption of the coating; the water resistance and outdoor durability of the coating are remarkably improved, and the problems that a traditional coating is poor in water resistance due to moisture absorption of a flame retardant and prone to stripping after being exposed to a humid environment for a long time are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and particularly to a high-performance polyethylene fireproof coating and a preparation method thereof. Background Art

[0002] Due to its light weight, corrosion resistance and easy processing, etc., polyethylene fireproof coatings are widely used in fields such as construction and cables. This coating uses polyethylene resin as the matrix and forms an intumescent flame retardant system by adding flame retardants, generating a carbon layer at high temperatures to delay the spread of flames. The polyethylene resin itself has excellent hydrophobicity, and the introduction of flame retardant fillers can further improve the fire resistance limit of the coating.

[0003] In the prior art, the flame retardant added to polyethylene fireproof coatings is usually zinc borate. Because the polar groups on its surface are easy to combine with water molecules, after absorbing moisture, it causes internal expansion stress in the coating, destroys the structural compactness, and weakens the adhesion between the coating and the substrate after water penetration, resulting in problems such as insufficient water resistance and coating peeling in the coating in a long-term humid environment.

[0004] Based on this, the present invention provides a high-performance polyethylene fireproof coating and a preparation method thereof. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-performance polyethylene fireproof coating and a preparation method thereof. The high-performance polyethylene fireproof coating prepared by the present invention not only has good water resistance performance, but also improves the adhesion and fireproof performance of the coating.

[0006] To achieve the above purpose, the present invention provides the following technical solution: A high-performance polyethylene fireproof coating and a preparation method thereof, including the following raw materials in parts by weight: 50 - 70 parts of polyethylene resin, 10 - 20 parts of hydrated zinc borate, 15 - 25 parts of flame-retardant expanded vermiculite powder, 5 - 10 parts of nano-ceramic microspheres, 3 - 8 parts of silane-modified glass fiber, 5 - 10 parts of flame-retardant plasticizer, 2 - 5 parts of surface treatment agent, and 1 - 3 parts of dispersant.

[0007] Preferably, the polyethylene resin can be selected from at least one of high-density polyethylene, linear low-density polyethylene and metallocene polyethylene.

[0008] Preferably, the particle size of the flame-retardant expanded vermiculite powder is 200 - 400 mesh, and its surface is coated with a layer of ammonium polyphosphate.

[0009] Preferably, the flame-retardant plasticizer can be selected from at least one or a combination of triphenyl phosphate, chlorinated paraffin and epoxidized soybean oil.

[0010] Preferably, the surface treatment agent can be selected from at least one of titanate coupling agent, silane coupling agent KH-570 and zinc stearate.

[0011] Preferably, the dispersant can be selected from at least one or a combination of sodium polyacrylate, sodium dodecyl sulfate, and sodium lignosulfonate.

[0012] Preferably, the method for preparing the nano-ceramic microspheres comprises the following steps: Step 1: Pretreatment of raw materials. Alumina, silica, and calcium carbonate are selected in a mass ratio of 3:2:1, added to a planetary ball mill with a ball-to-material ratio of 5:1, a rotation speed of 300 - 500 r / min, and argon gas is introduced for protection. Ball milling is carried out for 8 - 10 h to obtain a mixed powder. Step 2: High-temperature calcination. The mixed powder is transferred to a tube furnace, and the temperature is raised to 1300 - 1400 °C at a heating rate of 10 °C / min, held for 3 - 4 h, and then naturally cooled to 200 °C and taken out to obtain a porous ceramic matrix. Step 3: Silica sol impregnation. The porous ceramic matrix is placed in an ultrasonic cleaner, silica sol is added, the frequency is set at 40 - 45 kHz, the power is 300 - 400 W, and after treatment for 40 - 50 min, it is transferred to a centrifuge, and the rotation speed is set at 2000 - 3000 r / min for continuous dehydration for 30 - 40 min to obtain a base material. Step 4: Drying and shaping. The base material is transferred to a vacuum drying oven, the vacuum degree is set at -(0.08 - 0.09) MPa, the temperature is 90 - 100 °C, and drying treatment is carried out for 4 - 5 h to obtain nano-ceramic microspheres for use.

[0013] Preferably, in Step 1, the purity of alumina is ≥99%, the particle size of silica is 1 - 5 μm, the particle size of calcium carbonate is 200 - 250 mesh, and in Step 3, the mass ratio of the porous ceramic matrix to silica sol is 1:5.

[0014] Preferably, the method for preparing the silane-modified glass fiber comprises the following steps: Step 1: Pickling and activation. E-glass fibers with a diameter of 10 μm are immersed in a hydrochloric acid solution with a mass concentration of 5%, placed in a constant-temperature oscillator, the temperature is set at 20 - 25 °C, the rotation speed is 100 - 120 r / min, and continuous treatment is carried out for 15 - 20 min to obtain activated fibers. Step 2: Washing and neutralizing with water. The activated fibers are washed with deionized water until the pH value is 7, and then transferred to a forced-air drying oven, set at 80 - 85 °C, and pre-dried for 30 - 40 min to obtain dried fibers. Step 3: Coupling agent treatment. The dried fibers are immersed in an ethanol solution containing 3% silane coupling agent KH-550, transferred to a high-pressure reactor, the pressure is set at 0.4 - 0.5 MPa, the temperature is 50 - 60 °C, and under the condition of a stirring speed of 50 - 100 r / min, treatment is carried out for 1 - 2 h to obtain a fiber base material. Step 4: Secondary drying. Spread the fiber base material flat on a stainless-steel tray, transfer it to an inert gas drying oven, introduce nitrogen, set the flow rate at 10 L / min, and dry it for 2 - 3 h under the conditions of a temperature of 110 - 120 °C to obtain a fiber blank. Step 5: Surface carding. Arrange the orientation of the fiber blank through a fiber carding machine with a card clothing density of 20 teeth / cm² to obtain silane-modified glass fibers with a surface contact angle ≥ 110°, for later use.

[0015] Preferably, the preparation method of the high-performance polyethylene fireproof coating includes the following steps: S1: Weigh the polyethylene resin as needed and heat it to 160 - 180 °C until it melts, then add a flame retardant plasticizer and stir to mix, obtaining a molten mixture. S2: Transfer the molten mixture to a high-speed disperser, sequentially add zinc borate hydrate, flame retardant expanded vermiculite powder, and a dispersant, and disperse it at a high speed of 800 - 1000 r / min for 20 - 30 min to obtain a mixed material. S3: Transfer the mixed material to a vacuum planetary mixer, add nano-ceramic microspheres and silane-modified glass fibers, and perform a defoaming treatment at a vacuum degree of -0.08 MPa, a revolution speed of 30 r / min, and a rotation speed of 60 r / min for 15 - 20 min to obtain a mixture. S4: Transfer the mixture to a mixer, cool it to below 60 °C, add a surface treatment machine, set the stirring speed at 200 - 300 r / min, and continuously stir for 20 - 30 min to prepare the high-performance polyethylene fireproof coating.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. In this preparation method, the silane-modified glass fibers added in the preparation of the high-performance polyethylene fireproof coating form a hydrophobic network with the polyethylene resin through surface chemical bonding, blocking the moisture penetration path. The surface treatment agent further optimizes the surface energy of the coating, reducing the interaction between polar groups and water molecules. The two work together to build a stable hydrophobic barrier, greatly reducing the water absorption rate of the coating and significantly improving the water resistance and outdoor durability of the coating, solving the problems of poor water resistance of traditional coatings due to the moisture absorption of flame retardants and easy peeling after long-term exposure to a humid environment.

[0017] 2. In this preparation method, the nano-ceramic microspheres added in the preparation of the high-performance polyethylene fireproof coating are based on alumina and silica, and form a porous structure through high-temperature calcination. They absorb a large amount of heat through physical adsorption and chemical decomposition, delaying the temperature rise of the substrate. At the same time, they induce the pyrolysis of the polyethylene resin into carbon. The surface of the flame-retardant expanded vermiculite powder is coated with ammonium polyphosphate, which expands to form a honeycomb-like carbon-silicon layer at high temperature, covering the surface of the coating, isolating oxygen and blocking the diffusion of combustible gases. The two work together to form a dense and continuous carbon-silicon composite layer, effectively inhibiting the spread of flames, shortening the combustion self-extinguishing time, and significantly improving the flame-retardant performance, solving the problems of low flame-retardant efficiency of traditional polyethylene coatings, easy melting and dripping at high temperatures, and inability to form a stable barrier layer, thus meeting the requirements of high-fire scenarios.

[0018] 3. In this preparation method, the silane-modified glass fiber undergoes surface chemical bonding treatment to form a stable interfacial bond with the polyethylene resin. The silane coupling agent on the fiber surface bonds with the resin active groups through a hydroxyl condensation reaction. At the same time, the physical interpenetrating structure of the fiber forms a three-dimensional mechanical anchoring network in the coating, enhancing the mechanical interlocking effect between the coating and the substrate. The nano-ceramic microspheres improve the compatibility with the resin through surface silica sol modification, promote the uniform distribution of fillers in the dispersion process, reduce the agglomeration of components such as expanded vermiculite powder, and avoid interface defects caused by local stress concentration. Its rigid porous structure can also partially absorb the shrinkage stress during the curing process of the coating, relieve the difference in thermal expansion coefficients between the substrate and the coating, and inhibit the generation of microcracks. Under the synergistic action of the two, a dense and uniform composite structure is formed inside the coating, solving the problems of poor adhesion and easy peeling of traditional coatings due to uneven dispersion of fillers and weak interfacial bonding, and achieving a durable and firm bond between the coating and the substrate. Detailed implementation manners

[0019] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Embodiment

[0020] This embodiment provides a high-performance polyethylene fireproof coating and its preparation method, including the following raw materials in parts by weight: 50 parts of polyethylene resin, 10 parts of zinc borate hydrate, 15 parts of flame-retardant expanded vermiculite powder, 5 parts of nano-ceramic microspheres, 3 parts of silane-modified glass fiber, 5 parts of flame-retardant plasticizer, 2 parts of surface treatment agent, and 1 part of dispersant.

[0021] Among them, the polyethylene resin selects high-density polyethylene.

[0022] Among them, the particle size of the flame-retardant expanded vermiculite powder is 200 mesh, and its surface is coated with an ammonium polyphosphate layer.

[0023] Among them, triphenyl phosphate is selected as the flame retardant plasticizer.

[0024] Among them, titanate coupling agent is selected as the surface treatment agent.

[0025] Among them, sodium polyacrylate is selected as the dispersant.

[0026] Among them, the preparation method of nano-ceramic microspheres includes the following steps: Step 1: Raw material pretreatment, select alumina, silica and calcium carbonate according to the mass ratio of 3:2:1, add them to a planetary ball mill, with a ball-to-material ratio of 5:1, a rotation speed of 300 r / min, and argon gas protection, ball mill for 8 h to obtain a mixed powder; Step 2: High-temperature calcination, transfer the mixed powder to a tube furnace, set the heating rate to 10 °C / min and heat up to 1300 °C, keep warm for 3 h, and then naturally cool to 200 °C and take it out to obtain a porous ceramic matrix; Step 3: Silica sol impregnation, place the porous ceramic matrix in an ultrasonic cleaner, add silica sol, set the frequency to 40 kHz and the power to 300 W, after treating for 40 min, transfer it to a centrifuge, set the rotation speed to 2000 r / min and continuously dehydrate for 30 min to obtain a base material; Step 4: Drying and shaping, transfer the base material to a vacuum drying oven, set the vacuum degree to -0.08 MPa and the temperature to 90 °C, and carry out drying treatment for 4 h to obtain nano-ceramic microspheres for use.

[0027] Among them, in Step 1, the purity of alumina is ≥99%, the particle size of silica is 1 μm, the particle size of calcium carbonate is 200 mesh, and in Step 3, the mass ratio of the porous ceramic matrix to silica sol is 1:5.

[0028] Among them, the preparation method of silane-modified glass fiber includes the following steps: Step 1: Pickling and activation, immerse the E-glass fiber with a diameter of 10 μm in a hydrochloric acid solution with a mass concentration of 5%, place it in a constant temperature oscillator, set the temperature to 20 °C and the rotation speed to 100 r / min, and continuously treat for 15 min to obtain activated fibers; Step 2: Water washing and neutralization, wash the activated fibers with deionized water until the pH value is 7, transfer them to a blast drying oven, set the temperature to 80 °C, and pre-dry for 30 min to obtain dried fibers; Step 3: Coupling agent treatment, immerse the dried fibers in an ethanol solution containing 3% silane coupling agent KH-550, transfer them to a high-pressure reactor, set the pressure to 0.4 MPa, the temperature to 50 °C, and the stirring speed to 50 r / min, and treat for 1 h to obtain a fiber base material; Step 4: Secondary drying. Lay the fiber base material flat on a stainless-steel tray, transfer it to an inert gas drying oven, introduce nitrogen, set the flow rate at 10 L / min, and dry it for 2 h at a temperature of 110 °C to obtain a fiber blank. Step 5: Surface carding. Arrange the orientation of the fiber blank through a fiber carding machine with a card clothing density of 20 teeth / cm² to obtain silane-modified glass fibers with a surface contact angle ≥ 110°, for later use.

[0029] Among them, the preparation method of the high-performance polyethylene fireproof coating includes the following steps: S1: Weigh the polyethylene resin as needed and heat it to 160 °C for melting, then add a flame retardant plasticizer and stir to mix to obtain a molten mixture. S2: Transfer the molten mixture to a high-speed disperser, and sequentially add zinc borate hydrate, flame-retardant expanded vermiculite powder, and a dispersant, and disperse at a high speed for 20 min at 800 r / min to obtain a mixed material. S3: Transfer the mixed material to a vacuum planetary mixer, add nano-ceramic microspheres and silane-modified glass fibers, and perform a defoaming treatment for 15 min under a vacuum of -0.08 MPa, with a revolution speed of 30 r / min and a rotation speed of 60 r / min to obtain a mixture. S4: Transfer the mixture to a mixer, cool it to below 60 °C, add a surface treatment machine, set the stirring speed at 200 r / min, and continuously stir for 20 min to prepare the high-performance polyethylene fireproof coating. Example

[0030] A high-performance polyethylene fireproof coating and its preparation method include the following raw materials in parts by weight: 70 parts of polyethylene resin, 20 parts of zinc borate hydrate, 25 parts of flame-retardant expanded vermiculite powder, 10 parts of nano-ceramic microspheres, 8 parts of silane-modified glass fibers, 10 parts of flame retardant plasticizer, 5 parts of surface treatment agent, and 3 parts of dispersant.

[0031] Among them, the polyethylene resin selects linear low-density polyethylene.

[0032] Among them, the particle size of the flame-retardant expanded vermiculite powder is 400 mesh, and its surface is coated with a layer of ammonium polyphosphate.

[0033] Among them, the flame retardant plasticizer selects chlorinated paraffin.

[0034] Among them, the surface treatment agent selects silane coupling agent KH-570.

[0035] Among them, the dispersant selects sodium dodecyl sulfate.

[0036] Among them, the preparation method of the nano-ceramic microspheres includes the following steps: Step 1: Pretreatment of raw materials. Select alumina, silica and calcium carbonate according to a mass ratio of 3:2:1, add them to a planetary ball mill with a ball-to-material ratio of 5:1, a rotation speed of 500 r / min, and under argon protection, ball mill for 10 h to obtain a mixed powder; Step 2: High-temperature calcination. Transfer the mixed powder to a tube furnace, set the heating rate at 10 °C / min and heat up to 1400 °C, hold for 4 h, and then cool naturally to 200 °C and take out to obtain a porous ceramic matrix; Step 3: Silica sol impregnation. Place the porous ceramic matrix into an ultrasonic cleaner, add silica sol, set the frequency at 45 kHz and the power at 400 W, after treatment for 50 min, transfer it to a centrifuge and set the rotation speed at 3000 r / min to continuously dehydrate for 40 min to obtain a base material; Step 4: Drying and shaping. Transfer the base material to a vacuum drying oven, set the vacuum degree at -0.09 MPa and the temperature at 100 °C, and conduct drying treatment for 5 h to obtain nano-ceramic microspheres for later use.

[0037] Among them, in Step 1, the purity of alumina is ≥99%, the particle size of silica is 5 μm, and the particle size of calcium carbonate is 250 mesh. In Step 3, the mass ratio of the porous ceramic matrix to silica sol is 1:5.

[0038] Among them, the preparation method of silane-modified glass fiber includes the following steps: Step 1: Pickling and activation. Immerse the E-glass fiber with a diameter of 10 μm in a hydrochloric acid solution with a mass concentration of 5%, place it in a constant temperature oscillator, set the temperature at 25 °C and the rotation speed at 120 r / min, and continuously treat for 20 min to obtain activated fibers; Step 2: Washing and neutralizing. Wash the activated fibers with deionized water until the pH value is 7, transfer them to a blast drying oven, set at 85 °C, and pre-dry for 40 min to obtain dried fibers; Step 3: Coupling agent treatment. Immerse the dried fibers in an ethanol solution containing 3% silane coupling agent KH-550, transfer them to a high-pressure reaction kettle, set the pressure at 0.5 MPa, the temperature at 60 °C, and the stirring speed at 100 r / min, and treat for 2 h to obtain a fiber base material; Step 4: Secondary drying. Spread the fiber base material on a stainless steel tray, transfer it to an inert gas drying oven, introduce nitrogen, set the flow rate at 10 L / min, and dry at 120 °C for 3 h to obtain a fiber blank; Step 5: Surface carding. Arrange the orientation of the fiber blank through a fiber carding machine with a card clothing density of 20 teeth / cm² to obtain silane-modified glass fiber with a surface contact angle ≥110° for later use.

[0039] Among them, the preparation method of the high-performance polyethylene fireproof coating includes the following steps: S1: Weigh polyethylene resin as needed and heat it to 180 °C until it melts. Then add a flame retardant plasticizer and stir to mix, obtaining a molten mixture. S2: Transfer the molten mixture to a high-speed disperser, and sequentially add zinc borate hydrate, flame retardant expanded vermiculite powder, and a dispersant. Disperse at a high speed of 1000 r / min for 30 min to obtain a mixed material. S3: Transfer the mixed material to a vacuum planetary mixer, add nano-ceramic microspheres and silane-modified glass fibers. Carry out defoaming treatment for 20 min under the conditions of a vacuum degree of -0.08 MPa, a revolution speed of 30 r / min, and a rotation speed of 60 r / min to obtain a mixture. S4: Transfer the mixture to a mixer, cool it to below 60 °C, add a surface treatment machine, set the stirring speed at 300 r / min, and continuously stir for 30 min to prepare a high-performance polyethylene fireproof coating. Example

[0040] A high-performance polyethylene fireproof coating and its preparation method, including the following raw materials by weight: 60 parts of polyethylene resin, 15 parts of zinc borate hydrate, 20 parts of flame retardant expanded vermiculite powder, 8 parts of nano-ceramic microspheres, 6 parts of silane-modified glass fibers, 8 parts of flame retardant plasticizer, 4 parts of surface treatment agent, and 2 parts of dispersant.

[0041] Among them, the polyethylene resin selects metallocene polyethylene.

[0042] Among them, the particle size of the flame retardant expanded vermiculite powder is 300 mesh, and its surface is coated with a layer of ammonium polyphosphate.

[0043] Among them, the flame retardant plasticizer selects epoxy soybean oil.

[0044] Among them, the surface treatment agent selects zinc stearate.

[0045] Among them, the dispersant selects sodium lignosulfonate.

[0046] Among them, the preparation method of the nano-ceramic microspheres includes the following steps: Step 1: Raw material pretreatment. Select alumina, silica, and calcium carbonate according to a mass ratio of 3:2:1, add them to a planetary ball mill, with a ball-to-material ratio of 5:1, a rotation speed of 400 r / min, and under argon protection, ball mill for 9 h to obtain a mixed powder. Step 2: High-temperature calcination. Transfer the mixed powder to a tube furnace, set the heating rate at 10 °C / min and heat up to 1350 °C, keep it warm for 3.5 h, and then naturally cool to 200 °C and take it out to obtain a porous ceramic matrix. Step 3: Silica sol impregnation. Place the porous ceramic matrix into an ultrasonic cleaner, add silica sol, set the frequency to 43 kHz and the power to 350 W. After treating for 45 min, transfer it to a centrifuge and set the rotation speed to 2500 r / min to continuously dehydrate for 35 min to obtain the base material; Step 4: Drying and shaping. Transfer the base material to a vacuum drying oven, set the vacuum degree to -0.085 MPa and the temperature to 95 °C, and conduct drying treatment for 4.5 h to obtain nano-ceramic microspheres for standby.

[0047] Among them, in Step 1, the purity of alumina ≥ 99%, the particle size of silica is 35 μm, and the particle size of calcium carbonate is 230 mesh. In Step 3, the mass ratio of the porous ceramic matrix to the silica sol is 1:5.

[0048] Among them, the preparation method of the silane-modified glass fiber includes the following steps: Step 1: Pickling and activation. Immerse the E-glass fiber with a diameter of 10 μm in a hydrochloric acid solution with a mass concentration of 5%, place it in a constant temperature oscillator, set the temperature to 23 °C and the rotation speed to 110 r / min, and continuously treat for 18 min to obtain activated fibers; Step 2: Washing and neutralizing. Wash the activated fibers with deionized water until the pH value is 7, transfer them to a blast drying oven, set the temperature to 83 °C, and pre-dry for 35 min to obtain dried fibers; Step 3: Coupling agent treatment. Immerse the dried fibers in an ethanol solution containing 3% silane coupling agent KH-550, transfer them to a high-pressure reaction kettle, set the pressure to 0.45 MPa, the temperature to 55 °C, and stir at a speed of 80 r / min for 1.5 h to obtain fiber base materials; Step 4: Secondary drying. Spread the fiber base materials on a stainless steel tray, transfer them to an inert gas drying oven, introduce nitrogen, set the flow rate to 10 L / min, and dry at a temperature of 115 °C for 2.5 h to obtain fiber blanks; Step 5: Surface combing. Arrange the orientation of the fiber blanks through a fiber carding machine with a carding density of 20 teeth / cm² to obtain silane-modified glass fibers with a surface contact angle ≥ 110° for standby.

[0049] Among them, the preparation method of the high-performance polyethylene fireproof coating includes the following steps: S1: Weigh the polyethylene resin as required and heat it to 1700 °C for melting, then add a flame retardant plasticizer and stir and mix to obtain a molten mixture; S2: Transfer the molten mixture to a high-speed disperser, and successively add zinc borate hydrate, flame retardant expanded vermiculite powder, and a dispersant, and disperse at a high speed of 900 r / min for 25 min to obtain a mixed material; S3: Transfer the mixture to a vacuum planetary mixer, add nano-ceramic microspheres and silane-modified glass fibers, and perform degassing treatment for 18 min under the conditions of a vacuum degree of -0.08 MPa, a revolution speed of 30 r / min, and a rotation speed of 60 r / min to obtain a mixture; S4: Transfer the mixture to a mixer, cool it to below 60 °C, add a surface treatment machine, set the stirring speed at 250 r / min, and continuously stir for 25 min to prepare a high-performance polyethylene fireproof coating.

[0050] Comparative Example 1: The difference between this comparative example and Examples 1-3 is that nano-ceramic microspheres are not added in the process of preparing the high-performance polyethylene fireproof coating in this comparative example.

[0051] Comparative Example 2: The difference between this comparative example and Examples 1-3 is that silane-modified glass fibers are not added in the process of preparing the high-performance polyethylene fireproof coating in this comparative example.

[0052] Comparative Example 3: The difference between this comparative example and Examples 1-3 is that neither nano-ceramic microspheres nor silane-modified glass fibers are added in the process of preparing the high-performance polyethylene fireproof coating in this comparative example.

[0053] Comparative Example 4: The difference between this comparative example and Examples 1-3 is that the silane-modified glass fibers are not processed under pressure in a high-pressure reaction kettle and dried under nitrogen protection during the preparation process in this comparative example.

[0054] Perform performance tests on the high-performance polyethylene fireproof coatings prepared in Examples 1-3 and Comparative Examples 1-4, and record the obtained test data in the following table:

[0055] It can be seen from the comparison of the data in the table that the oxygen indices of the polyethylene fireproof coatings prepared by the preparation methods of Examples 1-3 are all ≥ 35.5%, and the oxygen indices of the polyethylene fireproof coatings prepared by the preparation methods of Comparative Examples 1-4 are ≤ 33%. Through analysis, it can be known that nano-ceramic microspheres are added in Examples 1-3, and their porous structure absorbs heat and expands at high temperatures, and cooperates with expanded vermiculite powder to form a dense carbon layer, effectively blocking the transfer of heat and oxygen. Nano-ceramic microspheres are not added in Comparative Examples 1 and 3, and the fireproof performance decreases significantly. This shows that nano-ceramic microspheres can significantly improve the fireproof performance of polyethylene fireproof coatings.

[0056] It can be seen from the comparison of the data in the table that the water absorption rates of the polyethylene fireproof coatings prepared by the preparation methods of Examples 1-3 are all ≤1.9%, and the water absorption rates of the polyethylene fireproof coatings prepared by the preparation methods of Comparative Examples 1-4 are ≥3.5%. Through analysis, it can be known that silane-modified glass fibers are added in Examples 1-3. The silane-modified glass fibers are combined with the polyethylene resin through chemical bonds to form a hydrophobic network structure. At the same time, the surface treatment agent further reduces the water absorption rate. In Comparative Examples 2 and 3, silane-modified glass fibers are not added, and the water resistance drops significantly. In Comparative Example 4, due to the lack of treatment in a high-pressure reactor and nitrogen protection, the fiber modification effect is average and the water absorption rate is high. This shows that silane-modified glass fibers can significantly improve the water resistance of polyethylene fireproof coatings.

[0057] It can be seen from the comparison of the data in the table that the adhesion of the polyethylene fireproof coatings prepared by the preparation methods of Examples 1-3 is all Grade 1, and the adhesion of the polyethylene fireproof coatings prepared by the preparation methods of Comparative Examples 1-4 is Grade 2-3. In Comparative Example 3, nano-ceramic microspheres and silane-modified glass fibers are not added, and the adhesion is the worst. Through analysis, it can be known that nano-ceramic microspheres and silane-modified glass fibers are added simultaneously in Examples 1-3, which can significantly improve the adhesion of the polyethylene fireproof coatings.

[0058] In the description of this specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0059] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A high-performance polyethylene fireproof coating and its preparation method, characterized in that, It comprises the following raw materials in parts by weight: 50 - 70 parts of polyethylene resin, 10 - 20 parts of zinc borate hydrate, 15 - 25 parts of flame-retardant expanded vermiculite powder, 5 - 10 parts of nano-ceramic microspheres, 3 - 8 parts of silane-modified glass fiber, 5 - 10 parts of flame-retardant plasticizer, 2 - 5 parts of surface treatment agent, and 1 - 3 parts of dispersant.

2. The high-performance polyethylene fireproof coating according to claim 1, wherein The polyethylene resin can be at least one selected from high-density polyethylene, linear low-density polyethylene, and metallocene polyethylene.

3. The high-performance polyethylene fireproof paint according to claim 1, characterized in that, The particle size of the flame-retardant expanded vermiculite powder is 200 - 400 mesh, and its surface is coated with a layer of ammonium polyphosphate.

4. The high-performance polyethylene fireproof coating according to claim 1, characterized in that, The flame-retardant plasticizer can be at least one or a combination of triphenyl phosphate, chlorinated paraffin, and epoxidized soybean oil.

5. The high-performance polyethylene fireproof coating according to claim 1, characterized in that, The surface treatment agent can be at least one selected from titanate coupling agent, silane coupling agent KH-570, and zinc stearate.

6. The high-performance polyethylene fireproof coating according to claim 1, characterized in that, The dispersant can be at least one or a combination of sodium polyacrylate, sodium dodecyl sulfate, and sodium lignosulfonate.

7. The high-performance polyethylene fireproof coating according to claim 1, wherein The preparation method of the nano-ceramic microspheres comprises the following steps: Step 1: Raw material pretreatment. Alumina, silica, and calcium carbonate are selected in a mass ratio of 3:2:1, added to a planetary ball mill with a ball-to-material ratio of 5:1, a rotation speed of 300 - 500 r / min, and argon gas protection. Ball milling is carried out for 8 - 10 h to obtain a mixed powder. Step 2: High-temperature calcination. The mixed powder is transferred to a tube furnace, and the temperature is raised to 1300 - 1400 °C at a heating rate of 10 °C / min, held for 3 - 4 h, and then naturally cooled to 200 °C and taken out to obtain a porous ceramic matrix. Step 3: Silica sol impregnation. The porous ceramic matrix is placed in an ultrasonic cleaner, silica sol is added, the frequency is set to 40 - 45 kHz, the power is 300 - 400 W, and after treatment for 40 - 50 min, it is transferred to a centrifuge, and the rotation speed is set to 2000 - 3000 r / min for continuous dehydration for 30 - 40 min to obtain a base material. Step 4: Drying and shaping. The base material is transferred to a vacuum drying oven, the vacuum degree is set to -(0.08 - 0.09) MPa, the temperature is 90 - 100 °C, and drying treatment is carried out for 4 - 5 h to obtain nano-ceramic microspheres for use.

8. The high-performance polyethylene fireproof coating according to claim 7, wherein In the said Step 1, the purity of alumina is ≥99%, the particle size of silica is 1 - 5 μm, and the particle size of calcium carbonate is 200 - 250 mesh. In the said Step 3, the mass ratio of the porous ceramic matrix to silica sol is 1:

5.

9. The high-performance polyethylene fireproof coating according to claim 1, characterized in that, The preparation method of the silane-modified glass fiber comprises the following steps: Step 1: Pickling activation. Alkali-free glass fiber with a diameter of 10 μm is immersed in a hydrochloric acid solution with a mass concentration of 5%, placed in a constant-temperature oscillator, the temperature is set to 20 - 25 °C, the rotation speed is 100 - 120 r / min, and continuous treatment is carried out for 15 - 20 min to obtain activated fiber. Step 2: Washing and neutralizing with water. The activated fiber is washed with deionized water until the pH value is 7, transferred to a blast drying oven, the temperature is set to 80 - 85 °C, and pre-dried for 30 - 40 min to obtain dried fiber. Step 3: Coupling agent treatment. Immerse the dried fibers in an ethanol solution containing 3% silane coupling agent KH-550, transfer them to a high-pressure reactor, set the pressure at 0.4 - 0.5 MPa, the temperature at 50 - 60 °C, and the stirring speed at 50 - 100 r / min, and treat for 1 - 2 h to obtain a fiber base material; Step 4: Secondary drying. Spread the fiber base material on a stainless-steel tray, transfer it to an inert gas drying oven, introduce nitrogen, set the flow rate at 10 L / min, and dry at 110 - 120 °C for 2 - 3 h to obtain a fiber blank; Step 5: Surface carding. Arrange the orientation of the fiber blank through a fiber carding machine with a card clothing density of 20 teeth / cm² to obtain silane-modified glass fibers with a surface contact angle ≥ 110°, for later use.

10. A method for preparing the high-performance polyethylene fireproof coating according to any one of claims 1 to 9, characterized in that, The method includes the following steps: S1: Weigh the polyethylene resin as needed and heat it to 160 - 180 °C for melting, then add a flame retardant plasticizer and stir to mix, obtaining a molten mixture; S2: Transfer the molten mixture to a high-speed disperser, successively add zinc borate hydrate, flame retardant expanded vermiculite powder, and a dispersant, and disperse at a high speed of 800 - 1000 r / min for 20 - 30 min to obtain a mixed material; S3: Transfer the mixed material to a vacuum planetary mixer, add nano-ceramic microspheres and silane-modified glass fibers, and perform degassing treatment at a vacuum degree of -0.08 MPa, a revolution speed of 30 r / min, and a rotation speed of 60 r / min for 15 - 20 min to obtain a mixture; S4: Transfer the mixture to a mixer, cool it to below 60 °C, add a surface treatment machine, set the stirring speed at 200 - 300 r / min, and continuously stir for 20 - 30 min to prepare a high-performance polyethylene fireproof coating.

Images