Indoor intumescent steel structure fireproof coating and preparation method thereof

Abstract

The present application relates to a kind of indoor intumescent steel structure fire-retardant coating and its preparation method, according to percentage by weight, including ammonium polyphosphate 12-16%, melamine 8-10%, pentaerythritol 5-7%, vinyl acetate-ethylene copolymer emulsion 25-30%, silicon dioxide-aramid composite 6-10%, filler 3-5%, smoke suppressant 0.5-1%, dispersant 3-5%, and the balance is water.The present application uses silicon dioxide-aramid composite and replaceable expandable graphite instead of ammonium polyphosphate, melamine and pentaerythritol, not only can effectively reduce the release of harmful gas in high temperature or flame combustion process, but also can effectively improve the fireproof performance of intumescent fire-retardant coating.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of indoor intumescent steel structure fire-retardant coating and its preparation method, belong to building coating material field. BACKGROUND

[0002] Intumescent fire-retardant coating is a kind of coating with expansion effect by adding intumescent flame retardant in coating.The expansion process of intumescent fire-retardant coating is: under the action of high temperature and flame, intumescent flame retardant in intumescent fire-retardant coating will have a series of chemical reactions, and form a dense carbon layer on the surface of coating, so as to isolate oxygen and temperature, and play a role of flame retardant.It is a composite environmental protection flame retardant mainly with C, P and N as main flame-retardant elements, with the characteristics of halogen-free, low toxicity, low smoke, preventing molten dripping and environmental friendly.Its flame-retardant mechanism: when polymer burns, acid source will first generate dehydrated inorganic acid, and react with hydroxyl group on carbon source to release water molecules;At the same time, gas source degrades to release non-combustible gas.With the rise of temperature, the material changes from hard to melt, and inert gas release will foam and expand the material;Temperature continues to rise, and the material further esterifies, dehydrates and carbonizes, and finally forms a porous and dense carbon layer.During the degradation process of the material, under the action of IFR, an expanded carbon layer with certain strength is generated on the surface of the material, which can isolate the contact of air and matrix, and isolate heat source at the same time, and has good flame retardancy.The most classic IFR flame-retardant system is a three-component mixed system of pentaerythritol / ammonium polyphosphate / melamine, and the three components account for more than 40% in coating, with high flame-retardant efficiency, but has the following problems: a large amount of toxic gas is generated during construction and curing, and the water resistance is poor;Most intumescent fire-retardant coatings use APP-MEL-PE flame-retardant system, so under the impact of flame or high temperature, a large amount of toxic gas will be released. SUMMARY

[0003] To solve the problems of poor water resistance and easy release of a large amount of toxic gas under high temperature of existing APP-MEL-PE flame-retardant system.

[0004] The technical scheme adopted by the present application is:

[0005] An indoor intumescent steel structure fire-retardant coating, according to weight percentage, includes ammonium polyphosphate 12-16%, melamine 8-10%, pentaerythritol 5-7%, vinyl acetate-ethylene copolymer emulsion 25-30%, silicon-fibroin composite 6-10%, filler 3-5%, smoke suppressant 0.5-1%, dispersant 3-5%, and the balance is water.

[0006] Further, preferably: the polymerization degree of the ammonium polyphosphate is ≥1000, and the non-volatile content of the vinyl acetate-ethylene copolymer emulsion is 54-56%.

[0007] Further, preferably: the filler is expandable graphite, alumina and titanium white, and the weight ratio of the expandable graphite, alumina and titanium white is 1:1:3.

[0008] Further, preferably: the smoke suppressant is one or a mixture of one or more of magnesium hydroxide, ferrocene, zinc stannate and diantimony trioxide.

[0009] Further, preferably: the dispersant is a wet dispersant.

[0010] Further, preferably: the preparation method of the silica-aramid composite is as follows:

[0011] (1) the aramid fiber is mixed with ethanol in a volume ratio of 1:1 and uniformly mixed, and ultrasonic treatment is performed;

[0012] (2) the aramid fiber after ultrasonic treatment is washed clean with pure water, and then steam explosion is performed;

[0013] (3) the aramid fiber after steam explosion is mixed with silica and uniformly ground;

[0014] (4) the ground aramid fiber and silica mixture is added to silane coupling agent, beta-cyclodextrin and water, the temperature is 60-80 DEG C, the reaction time is 4-6h, and the rotation speed is 400-600r / min;

[0015] (5) the product after reaction is dried at low temperature, crushed, and the silica-aramid composite is obtained.

[0016] Further, preferably: the ultrasonic treatment is specifically: ultrasonic power: 300-400W; time: 30-40min.

[0017] Further, preferably: the steam explosion is specifically: using time bomb explosion, pressure: 3.5-4.5MPa, time: 15-20min.

[0018] Further, preferably: the weight ratio of the aramid fiber, silica, silane coupling agent, beta-cyclodextrin and water is 1:4:0.5:1:5.

[0019] The preparation method of the indoor intumescent steel structure fireproof coating of the application comprises the following steps:

[0020] (1) according to the raw material ratio, pentaerythritol, silica-aramid composite, filler and smoke suppressant are mixed uniformly, stirred and dispersed for 30-60min, and the rotation speed is 1200-1500r / min;

[0021] (2) After the stirring of the raw materials, grind at room temperature for 30-40 min, 800-1000 r / min, and disperse into non-obvious caking particles;

[0022] (3) Add the remaining raw materials, rotate at 1200-1500 r / min, and stir and disperse for 30-40 min;

[0023] (4) Test and package.

[0024] The beneficial effects of the present application are:

[0025] The present application uses silica-aramid composite and expandable graphite to replace ammonium polyphosphate, melamine and pentaerythritol, which not only effectively reduces the release of harmful gases in the process of high temperature or flame combustion, but also effectively improves the fireproof performance of the intumescent fireproof coating.

[0026] The silica-aramid composite of the present application uses a combination of aramid fiber, silica, silane coupling agent and β-cyclodextrin, and is treated by a special process, so that it has good intumescent protective performance. The specific principle is as follows:

[0027] (1) Aramid fiber and silica can enhance each other's performance. Aramid fiber has high breaking strength, large elongation, soft feel, does not soften or melt at high temperature, only carbonizes, and has low smoke concentration and low heat release during combustion. Aramid fiber can increase the filling performance of silica, so that it has better dispersion and filling effect in the coating; silica can enhance the tensile strength and compression resistance of aramid fiber, so that the combination of the two can improve the mechanical properties and durability of the intumescent fireproof coating.

[0028] (2) The alkyl coupling agent can form a chemical bond between aramid fiber and silica, enhancing the interfacial bonding force between the two. The organic end of the silane coupling agent molecule forms a chemical bond with the fiber surface, while the inorganic end forms a chemical bond with the silica surface. Such coupling action can enhance the adhesion between the fiber and the silica, thereby improving the hydrophilicity and dispersibility of the aramid fiber, so that it can be better dispersed in the coating and improve the overall performance of the coating.

[0029] (3) β-cyclodextrin has intumescent properties in the coating. When exposed to high temperatures, β-cyclodextrin can absorb moisture and expand to form a microporous structure. This microporous structure can increase the volume of the coating and prevent heat conduction, thereby improving the fireproof performance of the intumescent fireproof coating. The presence of silica and silane coupling agent can further enhance the intumescent effect of β-cyclodextrin and improve the fireproof performance of the coating.

[0030] In addition, the filler of the present application uses expanded graphite. Expanded graphite, also known as expanded graphite paste, is a kind of graphite material with expansion property. It can expand at high temperature to form a porous structure, which plays a role in heat insulation and fire prevention.

[0031] In the expanded fireproof coating, the main functions of expanded graphite are as follows:

[0032] 1. Heat insulation performance: Expanded graphite can expand at high temperature to form a porous structure. This porous structure can gradually fill the voids in the coating to form a heat insulation layer. This can effectively block the heat transfer, reduce the surface temperature of the coating, and reduce the risk of fire occurrence and spread.

[0033] 2. Fireproof performance: Expanded graphite is a high-temperature resistant material that can resist high-temperature flames and smoke. When the coating is exposed to high temperature, expanded graphite will rapidly expand to form a dense porous structure. This porous structure can isolate oxygen and hinder the spread of flames and smoke. At the same time, expanded graphite can also absorb and dissipate heat, reducing the temperature of the flame and prolonging the burning time, thereby protecting the substrate and delaying the spread of fire.

[0034] 3. Increase the volume of the coating: The expansion property of expanded graphite can increase the volume of the coating. This volume expansion can form a three-dimensional network structure, increasing the thickness and solidity of the coating. At the same time, the increase in the volume of the coating can provide more heat resistance and enhance the fireproof performance of the coating. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below are only some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0036] Figure 1 The figure shows the comparison of the test piece before and after the fire resistance test. DETAILED DESCRIPTION

[0037] The technical solutions of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0038] The preparation method of the silica-aramid composite used in the present application is as follows:

[0039] (1) Aramid fiber and ethanol are mixed uniformly according to a volume ratio of 1:1, and ultrasonic treatment is performed, wherein the aramid fiber is original color aramid 1313, and the thickness and length are 1.67D and 5mm respectively;

[0040] (2) The aramid fiber after ultrasonic treatment is washed with pure water, and then steam explosion is performed;

[0041] (3) The aramid fiber after steam explosion is mixed uniformly with silica, and grinding is performed for 40min at a rotating speed of 1000r / min;

[0042] (4) The aramid fiber and silica mixture after grinding is added with a silane coupling agent, beta-cyclodextrin and water, and reaction is performed at a temperature of 80℃ for 5h at a rotating speed of 600r / min;

[0043] (5) The product after reaction is vacuum dried at 50℃, and is crushed to 300 mesh particles, so that a silica-aramid composite is obtained.

[0044] The ultrasonic treatment is specifically performed at an ultrasonic power of 300-400W for 30-40min, and the aramid fiber in the present embodiment is treated at an ultrasonic power of 300W for 40min. The ultrasonic treatment can effectively remove the slurry in the aramid fiber, so that the aramid fiber is better dispersed, and the subsequent reaction is facilitated.

[0045] The steam explosion is specifically performed at a pressure of 3.5-4.5MPa for 15-20min, and the QBS-80B type steam explosion process test table is used in the present embodiment at a pressure of 4.0MPa for 20min.

[0046] The aramid fiber is not soluble in water and emulsion, and when added to paint, there is a problem of uneven mixing due to stratification. The aramid fiber in the present embodiment is treated, and the hydrophilicity is greatly improved, so that the aramid fiber can be uniformly distributed in the paint, and no obvious stratification phenomenon occurs.

[0047] The aramid fiber is broken and crushed into smaller particles by the above treatment, so that the aramid fiber is more easily crushed. The product treated by the method of the present embodiment is dried and crushed, and the crushed product is sieved through a 200 mesh sieve, and the sieve residue is 5%.

[0048] Example 1

[0049] An indoor intumescent steel structure fireproof coating comprises, by weight percentage, ammonium polyphosphate 15%, melamine 10%, pentaerythritol 5%, vinyl acetate-ethylene copolymer emulsion 25%, silica-aramid composite 6%, filler 4%, smoke suppressant 0.5%, dispersant 4%, and the balance is water.

[0050] The polyphosphoric acid ammonium has a polymerization degree of ≥1000 and a particle size of 200 meshes, and is provided by Shandong Yunding Chemical Co., Ltd.

[0051] The non-volatile content of the vinyl acetate-ethylene copolymer emulsion is 54.5%.

[0052] The filler is expandable graphite, aluminum oxide and titanium white, and the weight ratio of the expandable graphite, aluminum oxide and titanium white is 1:1:3.

[0053] The smoke suppressant is diantimony trioxide.

[0054] The dispersant is a wet dispersant, and BYK110 wet dispersant is used.

[0055] The preparation method comprises the following steps:

[0056] (1) According to the raw material ratio, the pentaerythritol, the silicon dioxide-aramid composite, the filler and the smoke suppressant are uniformly mixed, stirred and dispersed for 30 min at a speed of 1500 r / min;

[0057] (2) The stirred raw materials are ground at room temperature for 40 min at a speed of 800 r / min, and are dispersed into no obvious caking particles;

[0058] (3) The remaining raw materials are added, stirred and dispersed for 30 min at a speed of 1500 r / min;

[0059] (4) Inspection and packaging.

[0060] Example 2

[0061] An indoor intumescent steel structure fireproof coating comprises, in percentage by weight, 12% of polyphosphoric acid ammonium, 8% of melamine, 6% of pentaerythritol, 26% of vinyl acetate-ethylene copolymer emulsion, 10% of silicon dioxide-aramid composite, 3% of filler, 0.5% of smoke suppressant, 3% of dispersant, and the balance of water.

[0062] The polyphosphoric acid ammonium has a polymerization degree of ≥1000 and a particle size of 200 meshes, and is provided by Shandong Yunding Chemical Co., Ltd.

[0063] The non-volatile content of the vinyl acetate-ethylene copolymer emulsion is 54.5%.

[0064] The filler is expandable graphite, aluminum oxide and titanium white, and the weight ratio of the expandable graphite, aluminum oxide and titanium white is 1:1:3.

[0065] The smoke suppressant is magnesium hydroxide.

[0066] The dispersant is a wet dispersant, and BYK110 wet dispersant is used.

[0067] The preparation method comprises the following steps:

[0068] (1) According to the raw material ratio, the pentaerythritol, the silica-aramid composite, the filler and the smoke suppressant are mixed uniformly, stirred and dispersed for 40 min at a speed of 1300 r / min;

[0069] (2) The stirred raw materials are ground at room temperature for 30 min at a speed of 1000 r / min, and are dispersed into no obvious caking particles;

[0070] (3) The remaining raw materials are added, stirred and dispersed for 30 min at a speed of 1300 r / min;

[0071] (4) Inspection and packaging.

[0072] Example 3

[0073] An indoor intumescent steel structure fireproof coating, according to the weight percentage, includes ammonium polyphosphate 16%, melamine 10%, pentaerythritol 7%, vinyl acetate-ethylene copolymer emulsion 30%, silica-aramid composite 8%, filler 5%, smoke suppressant 1%, dispersant 5%, and the balance is water.

[0074] The degree of polymerization of ammonium polyphosphate is ≥1000, and the particle size is 200 mesh from Shandong Yunding Chemical Co., Ltd.

[0075] The non-volatile content of the vinyl acetate-ethylene copolymer emulsion is 54.5%.

[0076] The filler is expandable graphite, aluminum oxide and titanium white, and the weight ratio of the expandable graphite, aluminum oxide and titanium white is 1:1:3.

[0077] The smoke suppressant is zinc stannate.

[0078] The dispersant is a wet dispersant, and BYK110 wet dispersant is used.

[0079] The preparation method thereof comprises the following steps:

[0080] (1) According to the raw material ratio, the pentaerythritol, the silica-aramid composite, the filler and the smoke suppressant are mixed uniformly, stirred and dispersed for 60 min at a speed of 1200 r / min;

[0081] (2) The stirred raw materials are ground for 40 min at room temperature at a speed of 800 r / min, and are dispersed into no obvious caking particles;

[0082] (3) The remaining raw materials are added, stirred and dispersed for 40 min at a speed of 1200 r / min;

[0083] (4) Inspection and packaging.

[0084] Example 4

[0085] An indoor intumescent steel structure fire retardant coating, comprising, in terms of weight percentage, ammonium polyphosphate 13%, melamine 9%, pentaerythritol 6%, vinyl acetate-ethylene copolymer emulsion 27%, silica-aramid composite 7%, filler 3%, smoke suppressant 1%, dispersant 4%, and the balance being water.

[0086] The degree of polymerization of the ammonium polyphosphate is ≥1000, and the particle size is 200 mesh, Shandong Yunding Chemical Co., Ltd.

[0087] The non-volatile content of the vinyl acetate-ethylene copolymer emulsion is 54.5%.

[0088] The filler is expandable graphite, aluminum oxide and titanium white, and the weight ratio of the expandable graphite, aluminum oxide and titanium white is 1:1:3.

[0089] The smoke suppressant is antimony trioxide.

[0090] The dispersant is a wet dispersant, and BYK110 wet dispersant is used.

[0091] A preparation method thereof, comprising the following steps:

[0092] (1) According to the raw material ratio, the pentaerythritol, silica-aramid composite, filler and smoke suppressant are uniformly mixed, stirred and dispersed for 40 min at a speed of 1300 r / min;

[0093] (2) The stirred raw materials are ground at room temperature for 40 min at a speed of 900 r / min, and dispersed to no obvious caking particles;

[0094] (3) The remaining raw materials are added, stirred and dispersed for 40 min at a speed of 1300 r / min;

[0095] (4) Inspection and packaging.

[0096] Comparative Example 1

[0097] The preparation method of the silica-aramid composite used is as follows:

[0098] (1) The aramid fiber and ethanol are uniformly mixed in a volume ratio of 1:1, and ultrasonic treatment is performed, and the aramid fiber is original color aramid 1313, with a thickness of 1.67D and a length of 5 mm;

[0099] (2) The aramid fiber treated by ultrasonic wave is washed clean with pure water, mixed uniformly with silica, and ground for 40 min at a speed of 1000 r / min;

[0100] (4) The mixture of milled aramid fiber and silica is added to silane coupling agent, β-cyclodextrin and water at a temperature of 80℃, and reacted for 5h at a rotation speed of 600r / min;

[0101] (5) The product after reaction is vacuum dried at 50℃, and crushed to 300 mesh particles to obtain the silica-aramid composite.

[0102] The ultrasonic treatment is specifically as follows: ultrasonic power: 300W; time: 40min.

[0103] Comparative Example 2

[0104] The same as Example 1, except that polyammonium phosphate, melamine and pentaerythritol are used instead of the silica-aramid composite, and the specific raw material ratio is as follows:

[0105] An indoor intumescent steel structure fireproof coating, according to the weight percentage, comprises polyammonium phosphate 18%, melamine 12%, pentaerythritol 1%, vinyl acetate-ethylene copolymer emulsion 25%, filler 4%, smoke suppressant 0.5%, dispersant 4%, and the balance is water.

[0106] Performance test:

[0107] The fireproof coatings prepared in Examples 1-4 and Comparative Examples 1 and 2 are tested for adhesive strength, water resistance, cold and hot cycle resistance and fire resistance according to GB 14907-2018 standard.

[0108] The fire resistance test uses GB / T 9978.1-2008 building fiber fire temperature test conditions: the test substrate is 36b hot-rolled I-beam (section modulus is 126m -1 ), the calculated span is 4200mm, the actual load is 207kN, and the coating thickness of the test piece is 3.0mm;

[0109] 2. The fire resistance test piece coating structure is as follows: HZ06-1 type epoxy zinc-rich anti-rust primer, fireproof coating, alkali-free glass fiber mesh cloth, fireproof coating, and special topcoat.

[0110] 3. The reference thermal insulation efficiency (coating thickness 2.08mm): 58min.

[0111] Smoke release: according to GB / T 8627-2007 Building Materials Smoke Density Test Method for Combustion or Decomposition, the coating is naturally air-dried, crushed, and then tested by pressing the air-dried coating into 25mm x 25mm x 6mm at a pressure of 5MPa for 10min.

[0112] The specific results are shown in Figure 1 and Table 1;

[0113] Figure 1 The fireproofing effect of the fireproof coating prepared in Example 3 before and after fireproofing is shown in Table 2. Figure 1 It can be seen that the indoor intumescent steel structure fireproof coating has good fireproof intumescent performance.

[0114] Table 1 Performance test results of fireproof coatings prepared in different examples

[0115]

[0116]

[0117] As can be seen from Table 1, the fireproof coating has excellent performance, and compared with Comparative Example 2 using an APP-MEL-PE flame-retardant system, the adhesion strength, water resistance, cold-heat cycle resistance and fire resistance are all significantly improved, and the smoke release amount is effectively reduced. The present application uses a silica-aramid composite, and the aramid fiber has high breaking strength, large elongation, soft hand feeling, does not soften or melt at high temperature, only carbonizes, and has low smoke concentration and low heat release during combustion. The aramid fiber forms a support layer after combustion, which has a heat insulation effect and can effectively reduce the average temperature of the test piece.

[0118] Steam explosion can reduce the diameter of aramid fiber, which is more conducive to grinding, and can increase the surface energy of aramid fiber, making it easier to disperse in liquid and increasing the interfacial compatibility with other materials. The aramid fiber of Comparative Example 1 of the present application is not treated by steam explosion, which leads to poor crushing effect of the aramid fiber, thereby affecting the reaction with silica, silane coupling agent and the like, and affecting the hydrophilicity and dispersibility of the coating. The residue after sieving of 200 mesh after crushing is 12%, which is much larger than 5% of the present application, resulting in a large amount of aramid fiber being sieved out and not entering the coating, thereby not playing the corresponding role, resulting in a significant decrease in the cold-heat cycle resistance and fire resistance of the coating.

[0119] Although the embodiments of the present application have been described above, modifications and replacements made by those skilled in the art without departing from the principles and spirits of the present application shall fall within the scope of the present application.

Claims

1. A fire-retardant coating for steel structures in buildings, characterized in that it comprises: According to the weight percentage, including polyphosphate 12-16%, melamine 8-10%, pentaerythritol 5-7%, vinyl acetate-ethylene copolymer emulsion 25-30%, silica-aramid composite 6-10%, filler 3-5%, smoke suppressant 0.5-1%, dispersant 3-5%, the balance is water; The preparation method of the silica-aramid composite is as follows: (1) Aramid fiber and ethanol are mixed uniformly according to a volume ratio of 1:1, and ultrasonic treatment is performed; (2) The aramid fiber after ultrasonic treatment is washed clean with pure water, and then steam explosion is performed; (3) The aramid fiber after steam explosion is mixed uniformly with silica, and grinding is performed; (4) The aramid fiber and silica mixture after grinding is added with silane coupling agent, β-cyclodextrin and water, the temperature is 60-80℃, the reaction time is 4-6h, and the rotation speed is 400-600r / min; (5) The product after reaction is dried at low temperature, crushed, and the silica-aramid composite is obtained; The ultrasonic treatment is specifically as follows: ultrasonic power: 300-400W; Time: 30-40min; The steam explosion is specifically as follows: using time bomb explosion, pressure 3.5-4.5MPa, time: 15-20min; The weight ratio of aramid fiber, silica, silane coupling agent, β-cyclodextrin and water is 1:4:0.5:1:5; The polyphosphate has a polymerization degree of ≥1000, the vinyl acetate-ethylene copolymer emulsion has a non-volatile content of 54-56%; The filler is expandable graphite, aluminum oxide and titanium white, and the weight ratio of the expandable graphite, aluminum oxide and titanium white is 1:1:

3.

2. The indoor intumescent steel structure fire-retardant coating according to claim 1, characterized in that: The smoke suppressant is one or a mixture of one or more of magnesium hydroxide, ferrocene, zinc stannate and diantimony trioxide.

3. The fire-retardant coating for indoor intumescent steel structure according to claim 1, characterized in that: The dispersant is a wet dispersant.

4. A process for the preparation of a fireproofing coating for steel structures in buildings according to any one of claims 1-3, characterized in that, The following steps are included: (1) According to the raw material ratio, pentaerythritol, silica-aramid composite, filler and smoke suppressant are mixed uniformly, and stirring and dispersion are performed for 30-60min at a rotation speed of 1200-1500r / min; (2) The raw material after stirring is ground at room temperature for 30-40min at a rotation speed of 800-1000r / min, and is dispersed to no obvious caking particles; (3) The remaining raw materials are added, the rotation speed is 1200-1500r / min, and stirring and dispersion are performed for 30-40min; (4) Inspection and packaging.

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