Aqueous intumescent cable fireproofing coating and method of making

Abstract

The application discloses a kind of water-based intumescent cable fire-retardant coating and preparation method, first take water as solvent, under low speed stirring state, add dispersing agent;Continue low speed stirring state to add carbonizing agent, foaming agent, dehydration carbonization catalyst, color filler, aluminum hydroxide composite flame retardant and ultraviolet absorber, after adding, using high speed stirring, add cosolvent in the process of stirring, obtain dispersion system;The dispersion system is ground, until system fineness≤60 μm, obtain sand mill slurry;Take the above sand mill slurry, under low speed stirring, add water-based emulsion, then add water-based bentonite slurry, defoaming agent and cosolvent, after high speed stirring, filter out insoluble, obtain water-based intumescent cable fire-retardant coating.The application uses aluminum hydroxide composite flame retardant to match N-P-C ternary flame-retardant system, segmented flame-retardant effect is generated, carbon layer expansion is effectively prolonged and substrate temperature rising rate is reduced.The application preparation process is simple, with low cost, quality stable characteristics.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of cable fireproof coating, and relates to a preparation technology of cable fireproof coating, in particular to a water-based intumescent cable fireproof coating and a preparation method. BACKGROUND

[0002] Power cable is an indispensable part of electrical engineering, and its main function is to transmit and distribute electric energy. With the rapid development of China's economy and the construction of urban informationization and modernization, the demand for power cable continues to increase, and the safe operation of power cable is particularly important. Power cable is flammable and connected in series, so materials with good fire resistance, flame retardation and heat insulation performance need to be used in cable design, and reasonable fireproof structure design needs to be adopted to ensure the normal operation of electrical systems. Intumescent fireproof coating has been widely used in the field of cable protection due to its excellent fireproof performance and good process performance.

[0003] Conventional intumescent fireproof coating usually uses acrylic resin or epoxy resin as the base material, and is matched with N-P-C ternary intumescent flame retardant system. Among them, ammonium polyphosphate is used as a dehydration carbon catalyst, pentaerythritol or di-pentaerythritol is used as a carbonizing agent, and melamine is used as a foaming agent. When exposed to fire or high temperature, these components work together to generate a heat-insulating carbonized layer, slowing down the temperature rise rate of the substrate in the fire environment. Aluminum hydroxide (ATH) is a commonly used metal oxide halogen-free flame retardant additive that can decompose and release water vapor under heating, and can react with ammonium polyphosphate to release non-combustible ammonia gas at high temperature, thereby reducing the surface temperature of the material and forming a heat barrier layer, which has the functions of flame retardation, smoke suppression and filling, and is widely used in various fireproof coatings.

[0004] However, in the water-based coating system, since each aluminum ion in the structure of aluminum hydroxide is surrounded by six hydroxyl ions and connected to each other through hydrogen bond interaction, based on the van der Waals force interaction between molecules, aluminum hydroxide can adsorb anions or small particles in an aqueous solution to form a flocculating body. The water-based fireproof coating system itself contains a large amount of pigment and filler, and mainly uses water as a diluent. Therefore, the use of untreated aluminum hydroxide in water-based coatings may have a negative impact on the storage stability and other film properties of the coating.

[0005] Phytic acid is a common bio-based phosphorus-containing flame retardant with a phosphorus content of 28%, which is the main source of phosphorus in plant tissues and mainly exists in the roots, stems and leaves of plants. As a recyclable natural resource, the acid produced by the pyrolysis of phytic acid can promote the rapid dehydration and carbonization of oxygen-containing polymer materials to form a dense coke layer, thereby effectively isolating the release of oxygen, heat and volatile flammable gases. However, when used alone as a flame retardant, phytic acid has low flame retardant efficiency, and due to its acidic nature, it is generally not suitable for direct use in conventional water-based acrylic emulsion systems. SUMMARY

[0006] To solve the above problems, the application provides an aluminum hydroxide composite flame retardant for water-based fireproof cable coating and a preparation method thereof.

[0007] To solve the above technical problems, the application adopts the technical scheme as follows:

[0008] On the one hand, the application provides a preparation method of water-based intumescent cable fireproof coating, including the following steps:

[0009] S1, taking water as a solvent, adding a dispersant under low-speed stirring;

[0010] S2, continuously adding a carbonizing agent, a foaming agent, a dehydration carbonization catalyst, a color filler, an aluminum hydroxide composite flame retardant and an ultraviolet absorber under low-speed stirring, adding the above-mentioned substances completely, then stirring at high speed, and adding a cosolvent in the stirring process to obtain a dispersion system;

[0011] S3, grinding the dispersion system until the fineness of the system is less than or equal to 60 microns to obtain a sanding slurry;

[0012] S4, taking the sanding slurry, adding a water-based emulsion under low-speed stirring, then adding a water-based bentonite slurry, a defoaming agent and a cosolvent, filtering out insoluble substances after high-speed stirring to obtain a water-based intumescent cable fireproof coating that can be used for coating.

[0013] The application also provides a preparation method of the above-mentioned aluminum hydroxide composite flame retardant, including the following steps:

[0014] S100, uniformly dispersing phytic acid (PA) in water for dilution;

[0015] S200, adding a silica sol aqueous solution to the phytic acid dispersion, stirring and mixing uniformly to obtain a dispersion system;

[0016] S300, neutralizing the dispersion system to neutral by a weak base;

[0017] S400, adding aluminum hydroxide (ATH);

[0018] S500, adding grinding balls for grinding and dispersing;

[0019] S600, collecting the filter residue after filtration, drying and then crushing and grinding again to obtain phytic acid-silica sol modified aluminum hydroxide composite flame retardant, which is denoted as PA-Si@ATH composite flame retardant.

[0020] Further, in step S100, the concentration of the phytic acid dispersed in water is 0.1-1 g / ml. Using a suitable concentration of phytic acid can achieve a better balance between the yield of the flame retardant and the quality of the product.

[0021] Further, in step S200, the mass concentration of the silica sol aqueous solution is 25-35%. Within this range, the silica sol aqueous solution can provide better modification effect.

[0022] Further, in the dispersion system, the mass ratio of phytic acid to silica sol is 0.5:1-1:0.5. A suitable mass ratio makes it easier to form a hydrophobic silica film.

[0023] Further, the dispersion system is stirred at room temperature for 1-4 hours to form. This time is sufficient for the dispersion system to be uniform, and it does not cause the preparation time to be too long.

[0024] Further, the weak base is ammonia, low-concentration sodium hydroxide, potassium hydroxide, and the most optimal is ammonia. Adjusting the pH value can also provide N elements to promote intumescent flame retardation.

[0025] Further, the mass ratio of aluminum hydroxide to phytic acid added is 1-7:1. A suitable ratio is conducive to forming a better isolation effect, so that the fireproof function of aluminum hydroxide can be fully utilized.

[0026] Further, in step S500, the grinding ball is zirconium beads, and the fineness after grinding is not greater than 20 microns.

[0027] Further, the particle size of the zirconium beads is 1-2 mm.

[0028] Further, in step S600, the filter residue is collected by centrifugal filtration, and after collection, the filter residue is rinsed with water multiple times.

[0029] Further, in step S600, after regrinding, the aluminum hydroxide composite flame retardant is obtained in the form of powder by passing through a 300-mesh sieve.

[0030] Further, the raw material composition of the water-based intumescent cable fire-retardant coating by weight is as follows:

[0031] Water-based emulsion 20-40 parts, dispersant 0.1-1.5 parts, char-forming agent 7-15 parts, foaming agent 7-15 parts, dehydration and carbonization catalyst 20-30 parts, color filler 5-10 parts, aluminum hydroxide composite flame retardant 3-10 parts, ultraviolet absorber 1-2 parts, cosolvent 2-6 parts, water-based bentonite slurry 0.5-1.5 parts, defoaming agent 0.1-1 part, deionized water 10-30 parts.

[0032] Further, the char-forming agent is any one or several of pentaerythritol, dipentaerythritol, phenol-formaldehyde resin, polyamide, butanetetrol, cyclohexanehexol and oxazine compound, and is preferably pentaerythritol.

[0033] Further, the foaming agent is a nitrogen-containing compound such as urea, melamine, polyamide, etc., and is preferably melamine.

[0034] Further, the dehydration and char-forming catalyst is any one or several of ammonium polyphosphate, phosphate ester and boric acid, and is preferably ammonium polyphosphate.

[0035] Further, the color filler is any one or several of titanium dioxide, talc, barium sulfate, calcium carbonate and silica powder, and is preferably a mixture of titanium dioxide and talc.

[0036] Further, the co-solvent is any one or several of dodecanol ester, propylene glycol, dipropylene glycol methyl ether, dipropylene glycol butyl ether, ethylene glycol phenyl ether and ethylene glycol butyl ether, and is preferably dodecanol ester and propylene glycol.

[0037] Further, the ultraviolet absorber includes UV-531 and Tinuvin 1130, etc.

[0038] Further, the aqueous emulsion is an acrylic emulsion or a vinyl acetate / acrylate copolymer such as King Industries TH-6681A, Wacker EZ 3066, Xiameter EMULTEX FR 728 and Bardac RS-6066, and is preferably RS-6066.

[0039] Further, the aqueous bentonite slurry is BYK LAPONITE RD, Himont BENTONE LT and CLAYMINTON HW, and is specifically RD.

[0040] Further, the defoaming agent is a mineral oil, a silicone, a polyether, a polyether-modified silicone such as BYK 024, 028, AFCONA-2503, 2505 and TEGO 810, and is preferably BYK 024.

[0041] Further, the dispersant is a sulfonate, a phosphate, a polyol type or a high-molecular type such as BYK 190 and TEGO 755W, and is specifically a high-molecular copolymer dispersion containing a pigment-affinity group such as BYK 190.

[0042] Further, in step S1, when the dispersant is added, the speed of low-speed stirring is 600-800 rpm, and the stirring time is 5-8 min.

[0043] Further, in step S2, the low speed is the same as in step S1, and the high speed stirring speed is 1500-2500 rpm, and the stirring time is 10-15 min.

[0044] Further, in step S2, during high speed stirring, part of the deionized water and a cosolvent can be used to clean the stirring shaft.

[0045] Further, in step S3, the grinding method is to add glass beads, replace the stirring paddle on the stirring shaft with a sand mill disc, and grind by driving the sand mill disc to rotate at high speed; after grinding, filter out the glass beads to obtain a sand mill slurry.

[0046] Further, in step S4, the low speed stirring speed is 600-800 rpm. After adding the emulsion, continue to stir for 5-10 min.

[0047] Further, in step S4, the high speed stirring speed is 1500-2500 rpm, and the dispersion time is 10-20 min.

[0048] On the other hand, the application also provides a water-based intumescent cable fireproof coating prepared by the above preparation method.

[0049] The flame-retardant mechanism of the aluminum hydroxide composite flame retardant used in the water-based fireproof cable coating is as follows:

[0050] Silica sol is a dispersion liquid of nanoscale silica particles dispersed in a solvent. Silica can crack the carbon layer and improve the oxidation resistance of the carbon layer when burning, thereby achieving a certain flame-retardant effect. Under suitable conditions, a layer of hydrophobic silica film can be formed on the surface of aluminum hydroxide by sol-gel method, cutting off the adsorption flocculation mechanism generated by aluminum ion hydrolysis ionization, while retaining the complete structure of aluminum hydroxide. Pure silica coating is not conducive to dispersion. Further, phytic acid and silica sol are grafted by silicon hydroxyl and hydrogen ion, forming a hydrophilic organic molecular segment, which can promote uniform dispersion in water and enhance the compatibility with the system, as shown in Figure 6 Based on the above method, the PA-Si@ATH composite flame retardant is prepared. Finally, the PA-Si@ATH composite flame retardant is added to the water-based cable coating system to prepare a fireproof coating with good fireproof performance and smoke suppression performance.

[0051] The coating of the intumescent fire-retardant paint generates acidic material polyphosphoric acid by thermal decomposition of ammonium polyphosphate when encountering fire or high temperature, and then the polyphosphoric acid undergoes esterification reaction with a polyol compound (pentaerythritol or dipentaerythritol), the product is dehydrated into carbon to form a carbon layer, at this time the base resin melts. The water vapor, ammonia gas and other gases generated by the esterification reaction and the non-combustible gas generated by melamine fill into the carbon layer, making the system expand and foam to form a porous foam carbon layer. However, the expanded carbon layer formed at this time has loose structure and low strength, and is prone to loose and fall off. The PA-Si@ATH-based composite flame-retardant material of the present application can produce segmented flame-retardant effect, effectively assist to prolong the carbon layer expansion time and strength of the system and reduce the substrate heating rate, and has the effects of catalyzing the reaction of the flame-retardant system, increasing the carbon content, improving the quality of the carbon layer, etc. At the initial stage of combustion, the outermost layer of phytic acid and ammonium polyphosphate synergistically decompose to generate some phosphorus-containing radicals such as HPO•, PO• and HPO2•, which can capture active HO• and H• generated in the combustion process of the polymer material, extinguish the combustion chain reaction, thereby reducing the flammability of the substrate and promoting the rapid dehydration and carbonization of the water-based acrylic polymer; then, the silica in the flame-retardant material shell participates in the catalytic carbonization reaction of pentaerythritol to generate an inorganic oxygen barrier and heat insulation protective layer with Si-O bond and / or Si-C bond and an expanded carbon layer, thereby improving the physical barrier effect; finally, the aluminum hydroxide in the core further releases water vapor to dilute the oxygen concentration at high temperature, delays the thermal decomposition of the polymer material, and reacts with the remaining ammonium polyphosphate at high temperature to generate aluminum phosphate, forming a protective layer and further improving the strength of the carbon layer and the residual carbon rate.

[0052] Compared with the prior art, the present application has the following beneficial effects:

[0053] (1) High flame-retardant and smoke-suppression efficiency, the segmented flame-retardant effect is produced by the synergistic effect of phytic acid, silica and aluminum hydroxide, which effectively assists to prolong the carbon layer expansion time and strength of the system and reduce the substrate heating rate, and has the effects of catalyzing the reaction of the flame-retardant system, increasing the carbon content, improving the quality of the carbon layer, etc.

[0054] (2) The phytic acid modified silica sol coats the aluminum hydroxide, which not only retains the complete structure of the aluminum hydroxide, but also promotes its more uniform dispersion in the paint system, thereby improving the compatibility and the comprehensive performance of the paint.

[0055] (3) The preparation process is simple, the PA-Si@ATH composite flame-retardant agent can be obtained by a mild reaction and preparation process, and the fire-retardant paint can be further prepared by reasonable process optimization, which has the characteristics of low cost and stable quality.

[0056] (4) Halogen-free environmental protection, PA-Si@ATH composite flame retardant, belongs to halogen-free flame retardant, non-toxic and efficient, has strong practical significance for the development of environmental protection industry and the wide use of green flame retardant, adapts to the trend of halogen-free flame retardant.

[0057] (5) The present application adopts aluminum hydroxide composite flame retardant to match N-P-C ternary flame retardant system, produces segmented flame retardant effect, effectively prolongs carbon layer expansion and reduces the heating rate of the substrate. BRIEF DESCRIPTION OF DRAWINGS

[0058] Figure 1 The preparation flow chart of the water-based intumescent cable fireproof coating of the present application.

[0059] Figure 2 The flow chart of preparing the aluminum hydroxide composite flame retardant of the present application.

[0060] Figure 3a The XRD pattern of aluminum hydroxide;

[0061] Figure 3b The XRD pattern of the phytic acid-silica sol mixture;

[0062] Figure 3c The XRD pattern of the modified aluminum hydroxide composite flame retardant.

[0063] Figure 4 The SEM morphology diagram of aluminum hydroxide before and after modification, wherein, Figure 4 (a) is the SEM morphology diagram of aluminum hydroxide before modification, Figure 4 (b) is the SEM diagram of aluminum hydroxide after modification, namely PA-Si@ATH.

[0064] Figure 5 The EDS element spectrum of aluminum hydroxide before and after modification, wherein, Figure 5 (a) is the EDS element spectrum of aluminum hydroxide before modification, Figure 5 (b) is the EDS element spectrum of aluminum hydroxide after modification, namely PA-Si@ATH.

[0065] Figure 6 The flame-retardant expansion schematic diagram of the cable fireproof coating after combustion in test example 1.

[0066] Figure 7 The schematic diagram of the grafting bonding principle of the surface phytic acid of aluminum hydroxide and silica sol through silicon hydroxyl and hydrogen ion. DETAILED DESCRIPTION

[0067] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is described in detail below with specific examples. It should be understood that the specific examples described herein are only used to explain the present application and are not limited to the present application. Any simple improvement of the preparation method of the present application under the concept of the present application is within the protection scope of the present application.

[0068] The preparation of the aluminum hydroxide composite flame retardant includes the following steps:

[0069] 10 g of phytic acid (PA) was uniformly dispersed in 20 ml of water for dilution, then 30 g of 30% silica sol aqueous solution was added dropwise to the PA dispersion, stirred at room temperature for 2 h, and the phytic acid was neutralized with ammonia water to make the pH of the system neutral, then 40 g of ATH powder was added, and an equal volume of zirconium beads with a particle size of 1-2 mm was added for grinding and dispersion, the fineness was less than 20 microns, the upper suspension was centrifuged and filtered, and multiple water rinsing was performed, then the filter was dried and crushed, and passed through a 300 mesh sieve to obtain the phytic acid-silica sol modified aluminum hydroxide composite flame retardant, marked as PA-Si@ATH.

[0070] The qualitative analysis of the XRD test of the samples before and after modification of the aluminum hydroxide is shown in Figures 3a-3c . Figure 3a The XRD pattern of the unmodified aluminum hydroxide is Figure 3b , the XRD pattern of the phytic acid-silica sol mixture is Figure 3c , and the XRD pattern of the modified aluminum hydroxide composite flame retardant is Figure 3a . The diffraction peak is sharp and the phase is clear, indicating that the crystallinity of the aluminum hydroxide is good and the purity is high. Figure 3a Since the silicon dioxide is an amorphous structure, such non-crystal structure has more burrs in the X-ray diffraction pattern, and the characteristic peak of amorphous silicon dioxide is around 23°. Figure 3c In the figure, a very long and sharp diffraction peak corresponding to aluminum hydroxide can be observed, and the overall amorphous peak area is large and the characteristic is more obvious, indicating that there is a large amount of silicon dioxide on the surface of the aluminum hydroxide. The SEM morphology analysis of the aluminum hydroxide before and after modification is shown in Figure 4 . Figure 4 In the figure, (a) is the SEM graph of the aluminum hydroxide before modification, Figure 4 (b) is the SEM graph of the aluminum hydroxide after modification, i.e. PA-Si@ATH; from Figure 4 the figure, it can be seen that the surface of the original aluminum hydroxide is relatively smooth and uniformly distributed, and after treatment and modification, the corners of the aluminum hydroxide are no longer prominent. The EDS element spectrum measurement of the aluminum hydroxide before and after modification is shown in Figure 5 . Figure 5 In the figure, (a) is the EDS element graph of the aluminum hydroxide before modification, Figure 5The middle (b) is the EDS element map of the modified aluminum hydroxide, i.e. PA-Si@ATH. The original aluminum hydroxide is analyzed by surface scanning. The main elements are Al and O, indicating that the purity is high. After modification, Si and P elements are added on the surface, indicating that the phytic acid modified silica sol is coated on the surface of the aluminum hydroxide. According to the XRD, SEM and EDS analysis in FIG. 3-3, it can be seen that the phytic acid modified silica sol is successfully coated on the surface of the aluminum hydroxide particles.

[0071] The PA-Si@ATH-based water-based intumescent fireproof coating was prepared by using the above-prepared aluminum hydroxide composite flame retardant as follows:

[0072] Example 1:

[0073] i Preparation of slurry:

[0074] Take 14.5 parts of deionized water, slowly add 0.5 parts of dispersant at a speed of 300-500 rpm for 5-8 min, then add 9 parts of melamine (MEL), 9 parts of pentaerythritol (PER), 20 parts of ammonium polyphosphate (APP), 8 parts of mixed pigment and filler (titanium dioxide: talc mass ratio 7:2), 4 parts of PA-Si@ATH composite flame retardant, 1 part of ultraviolet absorber (UV-531), and adjust the speed to 2000 rpm for 10-15 min. During this process, the stirring shaft and cylinder wall powder are cleaned with 1 part of propylene glycol and 2 parts of deionized water; then replace the sand mill disc, add glass beads with a weight ratio of 1:1, open the circulating water of the sand mill cylinder, and continue to stir and grind and disperse until the system fineness is ≤60 μm; filter to obtain the sand mill slurry.

[0075] ii Preparation of coating:

[0076] Take the above sand mill slurry, slowly add 28 parts of water-based emulsion at a speed of 600-800 rpm, stir for 5-10 min; 1 part of 10% water-based bentonite slurry, then add 0.3 parts of defoaming agent and the remaining 2 parts of dodecanol ester, continue to disperse at 1500-2500 rpm for 10-20 min, and then filter and package to obtain the intumescent water-based cable protective coating.

[0077] Example 2:

[0078] i Preparation of slurry:

[0079] Take 14.5 parts of deionized water, slowly add 0.5 parts of dispersant under the speed of 300-500 rpm for 5-8 min, then add 9 parts of melamine (MEL), 9 parts of pentaerythritol (PER), 20 parts of ammonium polyphosphate (APP), 8 parts of mixed color filler (titanium dioxide: talc mass ratio 7:2), 1 part of PA-Si@ATH composite flame retardant, 1 part of ultraviolet absorber (UV-531), and adjust the speed to 2000 rpm for 10-15 min of dispersion, during which 1 part of propylene glycol and 2 parts of deionized water are used to clean the stirring shaft and cylinder wall powder; then replace the sand mill disc, add glass beads with a weight ratio of 1:1, open the circulating water of the sand mill cylinder, continue to stir, grind and disperse until the system fineness is ≤60 μm; filter to obtain the sand mill slurry.

[0080] ii Coating preparation:

[0081] Take the above sand mill slurry, slowly add 28 parts of water-based emulsion under the speed of 600-800 rpm for 5-10 min; 1 part of 10% water-based bentonite slurry, then add 0.3 parts of defoaming agent and the remaining cosolvent 2 parts of dodecanol ester, continue to disperse at 1500-2500 rpm for 10-20 min, after uniform dispersion, filter and package to obtain the intumescent water-based cable protective coating.

[0082] Comparative Example 1

[0083] i Slurry preparation:

[0084] Take 14.5 parts of deionized water, slowly add 0.5 parts of dispersant under the speed of 300-500 rpm for 5-8 min, then add 9 parts of melamine (MEL), 9 parts of pentaerythritol (PER), 20 parts of ammonium polyphosphate (APP), 8 parts of mixed color filler (titanium dioxide: talc mass ratio 7:2), 4 parts of unmodified aluminum hydroxide, 1 part of ultraviolet absorber (UV-531), and adjust the speed to 2000 rpm for 10-15 min of dispersion, during which 1 part of propylene glycol and 2 parts of deionized water are used to clean the stirring shaft and cylinder wall powder; then replace the sand mill disc, add glass beads with a weight ratio of 1:1, open the circulating water of the sand mill cylinder, continue to stir, grind and disperse until the system fineness is ≤60 μm; filter to obtain the sand mill slurry.

[0085] ii Coating preparation:

[0086] Take the above sand mill slurry, slowly add 28 parts of water-based emulsion under the speed of 600-800 rpm for 5-10 min; 1 part of 10% water-based bentonite slurry, then add 0.3 parts of defoaming agent and the remaining cosolvent 2 parts of dodecanol ester, continue to disperse at 1500-2500 rpm for 10-20 min, after uniform dispersion, filter and package to obtain the intumescent water-based cable protective coating.

[0087] Comparative Example 2

[0088] i Preparation of slurry:

[0089] Take 14.5 parts of deionized water, slowly add 0.5 parts of dispersant under the speed of 300-500 rpm for 5-8 min, then add 9 parts of melamine (MEL), 9 parts of pentaerythritol (PER), 20 parts of ammonium polyphosphate (APP), 8 parts of mixed pigment and filler (titanium dioxide: talc mass ratio 7:2), 4 parts of silica sol, 1 part of ultraviolet absorber (UV-531), and adjust the speed to 2000 rpm for 10-15 min of dispersion. During this process, the stirring shaft and cylinder wall powder are cleaned with 1 part of propylene glycol and 2 parts of deionized water; then replace the sand mill disc, add glass beads with a weight ratio of 1:1, open the circulating water of the sand mill cylinder, and continue to stir and grind and disperse until the system fineness is ≤60 μm; filter to obtain the sand mill slurry.

[0090] ii Preparation of coating:

[0091] Take the above sand mill slurry, slowly add 28 parts of water-based emulsion under the speed of 600-800 rpm for 5-10 min; 1 part of 10% water-based bentonite slurry, then add 0.3 parts of defoaming agent and the remaining 2 parts of dodecanol ester, continue to disperse at 1500-2500 rpm for 10-20 min, after uniform dispersion, filter and package to obtain the intumescent water-based cable protective coating.

[0092] The cable coating prepared in the above Examples 1, 2 and Comparative Examples 1, 2 is tested for performance, and the results are shown in the following table;

[0093] Table 1 Performance of cable fireproof coating

[0094]

[0095] As can be seen from Table 1 above, the addition of PA-Si@ATH composite flame retardant can significantly improve the flame retardant performance, and has excellent performance, fully meeting the requirements of GB / T 28374 cable fireproof coating standard. Further, the XRD of Figure 3 shows that amorphous silicon dioxide can form a coating on the surface of ATH, Figure 4 and Figure 5 The morphology of aluminum hydroxide before and after modification and the EDS element map of the surface are shown, and the surface of the modified aluminum hydroxide has Si and P elements, which can play a synergistic effect in the cable fireproof coating. As shown in Figure 6 , the PA-Si@ATH-based water-based intumescent cable fireproof coating in Test Example 1 has excellent intumescent flame retardant effect, and a white aluminum-containing protective layer can be formed on its surface.

[0096] The above embodiments are only used for illustrating the present application, but not limiting the present application. Although the present application is explained in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications or equivalent replacements of the technical solutions of the present application do not deviate from the spirit and scope of the present application, and should be covered in the scope of the claims of the present application.

Claims

1. A process for the preparation of an aqueous intumescent fire-retardant coating for cables, characterized in that, The method comprises the following steps: Take water as solvent, and add dispersant under stirring; Continue to add carbonization agent, foaming agent, dehydration carbonization catalyst, color filler, aluminum hydroxide composite flame retardant and ultraviolet absorber under stirring, stir after adding, and add dissolving aid during stirring to obtain a dispersion system; Grind the dispersion system until the fineness of the system is less than or equal to 60 microns to obtain a sand mill slurry; Take the sand mill slurry, add water-based emulsion under stirring, then add water-based bentonite slurry, defoaming agent and dissolving aid, filter out insoluble substances after stirring to obtain a water-based intumescent cable fireproof coating that can be used for coating; The preparation method of the aluminum hydroxide composite flame retardant comprises the following steps: Dilute the phytic acid by uniformly dispersing it in water; Add a silica sol aqueous solution to the phytic acid dispersion, stir and mix uniformly to obtain a dispersion system; Neutralize the dispersion system to neutral with a weak base; Add aluminum hydroxide; Add grinding balls for grinding and dispersing; Collect the filter residue after filtration, dry and then crush and grind again to obtain a phytic acid-silica sol modified aluminum hydroxide composite flame retardant.

2. The process for the preparation of the water-based intumescent fire-retardant coating according to claim 1, characterized by the fact that: The raw material composition of the water-based intumescent cable fireproof coating by weight is as follows: Water-based emulsion 20-40 parts, dispersant 0.1-1.5 parts, carbonization agent 7-15 parts, foaming agent 7-15 parts, dehydration carbonization catalyst 20-30 parts, color filler 5-10 parts, aluminum hydroxide composite flame retardant 3-10 parts, ultraviolet absorber 1-2 parts, dissolving aid 2-6 parts, water-based bentonite slurry 0.5-1.5 parts, defoaming agent 0.1-1 part, deionized water 10-30 parts.

3. The process for the preparation of the water-based intumescent fire-retardant coating according to claim 2, characterized by the fact that: The carbonization agent is any one or several of pentaerythritol, di-pentaerythritol, phenolic resin, polyamide, butane tetrol, cyclohexane hexanol and xanthine compounds.

4. The process for the preparation of water-based intumescent fire-retardant coating according to claim 2, characterized in that: The dehydration carbonization catalyst is any one or several of ammonium polyphosphate, phosphate ester and boric acid.

5. The process for the preparation of water-based intumescent fire-retardant coating according to claim 2, characterized in that: The color filler is any one or several of titanium dioxide, talc powder, barium sulfate, calcium carbonate and silica powder.

6. The process for the preparation of water-based intumescent fire-retardant coating according to claim 2, characterized in that: The dissolving aid is any one or several of dodecanol ester, propylene glycol, dipropylene glycol methyl ether, dipropylene glycol butyl ether, ethylene glycol phenyl ether and ethylene glycol butyl ether.

7. The process for the preparation of water-based intumescent fire resistant coating according to claim 2, characterized in that: The ultraviolet absorber includes UV-531 and Tinuvin 1130.

8. An aqueous intumescent fire resistant coating, characterized in that, Prepared by the preparation method of any one of claims 1-7.

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