CN108559321B

CN108559321B - Ultrathin fireproof water-based paint

Info

Publication number: CN108559321B
Application number: CN201810482892.1A
Authority: CN
Inventors: 郑善
Original assignee: Tianjin Longhua Ruibo Technology Co Ltd
Current assignee: Tianjin Longhua Ruibo Technology Co., Ltd
Priority date: 2017-06-28
Filing date: 2017-06-28
Publication date: 2020-06-09
Anticipated expiration: 2037-06-28
Also published as: CN108676395A; CN107254204A; CN108676395B; CN108676396A; CN107254204B; CN108559321A; CN108676396B

Abstract

The invention belongs to the field of water-based paint, and particularly relates to ultrathin fireproof water-based paint. When the fireproof water-based paint is prepared, a component A and a component B are added, wherein the component A comprises an aerogel precursor, stepless powder and the like, and the component B is used as a bonding agent. According to the invention, the aerogel precursor is used as a core raw material to prepare the water-based fireproof coating, and as the aerogel material has a nano three-dimensional structure, the characteristics of effectively prolonging a solid heat conduction path, inhibiting gas convection heat transfer and reducing heat radiation are achieved, and the aerogel fireproof coating prepared by the aerogel material has heat insulation performance incomparable with the traditional material; after the fireproof water-based paint is coated on steel and dried, the fireproof water-based paint has high mechanical strength, realizes the fireproof A1 grade, has the advantages of good waterproof performance and low cost, and provides a novel material for building, environmental protection and industrial energy conservation.

Description

Ultrathin fireproof water-based paint

The application is a divisional application of a Chinese invention patent with the patent application number of 201710509731.2 (application date: 2017, 06, 28 and the name: an ultrathin fireproof water-based paint and a preparation method thereof).

Technical Field

The invention belongs to the field of water-based paint, and particularly relates to ultrathin fireproof water-based paint.

Background

The steel is not flammable, but has a high thermal conductivity, and the thermal conductivity at room temperature reaches 58.2W/mK. When the temperature of the steel reaches about 500 ℃ in fire or heat, the elastic modulus, the yield strength and the ultimate strength of the steel are obviously reduced, and the strain is rapidly increased, so that the steel is rapidly distorted and deformed, and the partial or whole collapse and damage of the steel structure are caused. Experiments show that the steel has the characteristic of heat resistance but not high temperature resistance, and the strength of the steel is gradually reduced along with the increase of the temperature. When the temperature of the steel structural member reaches 350 ℃, 500 ℃ and 600 ℃ under the action of fire, the strength is respectively reduced by 1/3, 1/2 and 2/3. When the temperature reaches above 500 ℃, the steel structural member softens and the building collapses and collapses instantly. The expansion type fireproof coating coated on the surface of the steel structure can prolong the supporting time of the steel structure building in fire, and win the time for people to evacuate from the fire scene.

The steel structure fire-retardant coating is developed to the present, and can be classified by different methods: the dispersion systems used are classified into water-soluble type and solvent type; the fire-proof type is classified into an expansion type and a non-expansion type; on the application range, the indoor type and the outdoor type are classified; the thickness is classified into a thick coating type, a thin coating type and an ultra thin type. The currently common medium-thickness coating and thin-coating coatings are mostly water-soluble, and ultra-thin coatings are water-soluble and solvent-soluble. Both the thin coating type and the ultra-thin type are basically expansion type, and the thick coating type is non-expansion type.

In recent years, with the increasing awareness of environmental protection, water-based fire-retardant coatings have received more and more attention. The water-based fireproof coating takes water as a solvent, so the price is lower than that of the oil-based fireproof coating, and the pollution to the atmosphere is reduced; the water-based paint only adopts a small amount of or does not adopt an organic solvent, so that the operation environment is improved, and meanwhile, the effects on reducing pollution and saving resources are obvious; the water-based paint coating has strong adhesive force and better adaptability to the surface of the material; the water-based paint construction coating tool can be cleaned by water, so that the consumption of a cleaning solvent is reduced; the water-based fireproof coating has good flattening performance, can be constructed at the positions of an inner cavity, a welding line, a corner angle, an edge and the like, and has good protection performance.

The flame retardant principle of the water-based fireproof coating is as follows: (1) inherently flame retardant or non-combustible. After the coating is heated in case of fire, a large amount of heat can be absorbed through physical changes such as melting and expansion and chemical actions such as decomposition and carbonization of components such as polymers and the like, and part of heat acting on an object is counteracted, so that the heating temperature rise process of the base material is delayed; (2) the incombustible inert gas is decomposed by heating when encountering fire, and the inflammable gas decomposed by heating of the protected substrate and oxygen in the air are diluted to inhibit combustion; (3) release active free radical when heated. The active free radical can slow down or stop the combustion chain reaction after being combined with the organic free radical; (4) the base material expands when heated to form an expanded carbon layer for heat insulation and oxygen insulation, and the base material is sealed, so that the base material is prevented from igniting and burning.

Patent CN102675992B describes an intumescent water-based facing fire retardant coating prepared from styrene-acrylic emulsion, ammonium polyphosphate, pentaerythritol, melamine, titanium dioxide, aluminum hydroxide, zinc borate, chlorinated paraffin, antiseptic, dispersant, film forming aid, cellulose ether, hydroxyl silicone oil and water. The product is soaked in water for 72 hours, and has no cracking, no bubbling and no falling off, and the fire-resistant time is 40 min. However, the fireproof coating has a short fire-resistant time due to the lack of strength and durability of the expanded carbon generated in a fire.

In addition, in the practical application of the fireproof coating in the existing market, the thickness of the coating is generally 20mm, and the problems of poor decoration and inconvenient construction can be caused by excessively thick coating.

Therefore, how to prepare a fire retardant coating with light and thin coating and long fire resistance time is a technical problem to be solved at present.

Disclosure of Invention

The invention aims to provide an ultrathin fireproof water-based paint aiming at the defects of the prior art, and the aerogel with good heat resistance is added into the fireproof water-based paint for modification, so that the heat conductivity coefficient of a coating can be effectively reduced. When the aerogel precursor meets fire, the oxidation process of the aerogel precursor and the fire compete for oxygen and heat, and then the aerogel forms a microscopic nano porous structure under the action of temperature, so that the aerogel has an ultra-strong heat insulation effect. In addition, the components such as cordierite, mullite and the like in the fireproof water-based paint expand to absorb a large amount of heat when encountering fire in the combustion process, and offset part of the heat acting on an object, so that the heating temperature rise process of the base material is delayed, and meanwhile, a ceramic membrane capable of resisting heat of thousands of degrees is generated on the surface of steel, so that the fireproof durability is effectively enhanced.

In order to achieve the purpose, the invention adopts the following technical scheme:

an ultrathin fireproof water-based paint comprises a component A and a component B; the weight part ratio of the component A to the component B is 0.5-1.5: 1;

the component A comprises, by weight, 30-70 parts of aerogel precursor, 3-15 parts of kaolin, 5-20 parts of cordierite, 8-25 parts of bentonite, 2-10 parts of diatomite, 2-10 parts of closed-cell perlite, 1-8 parts of ceramic fiber, 1-10 parts of titanium dioxide, 1-10 parts of wollastonite powder, 5-15 parts of mullite, 0.5-10 parts of heavy calcium material and 0.5-8 parts of alumina;

the component B comprises, by weight, 10-60 parts of sodium water glass, 10-60 parts of potassium water glass, 30-90 parts of water, 5-40 parts of silica sol, 1-15 parts of aluminum phosphate, 1-10 parts of coupling agent A, 1-15 parts of film forming additive, 5-30 parts of bentonite, 1-15 parts of organosilicon modified acrylic emulsion, 1-8 parts of flatting agent and 1-8 parts of film forming agent.

The components such as cordierite, mullite and the like in the fireproof water-based paint expand to absorb a large amount of heat when encountering fire in the combustion process, and offset part of the heat acting on an object, so that the heating temperature rise process of a base material is delayed, and meanwhile, ceramics which can resist heat of thousands of degrees are generated on the surface of steel, thereby effectively enhancing the fireproof durability.

As a preferred technical scheme:

in the ultrathin fireproof water-based paint, except the aerogel precursor and the ceramic fiber, the components A are solid powder with the diameter ranging from 0.5mm to 1.5 mm.

In the ultrathin fireproof water-based paint, the length of the ceramic fiber in the component A is less than 2mm, and the diameter is less than 20 μm.

The ultrathin fireproof water-based paint is characterized in that the leveling agent is a polyether siloxane leveling agent;

the film-forming auxiliary agent is ethylene glycol, propylene glycol, dodecyl alcohol ester or ethylene glycol butyl ether acetate;

the coupling agent A is one or two of KH560 and KH 550;

the film forming agent is selected from vinyl acetate-vinyl versatate polymerized emulsion, polyvinyl acetate emulsion, styrene-acrylic ester emulsion or polystyrene modified emulsion.

According to the ultrathin fireproof water-based paint, the solid content of the aerogel precursor is 5-35%; the water content of the silica sol is less than or equal to 70 percent, and the solid content of the organic silicon modified acrylic emulsion is more than or equal to 60 percent. The silica sol is a dispersion liquid of nano-scale silica particles in water, and the solid content of the organosilicon modified acrylic emulsion refers to the content of organosilicon modified acrylic solid in the emulsion.

The compression strength of the ultrathin fireproof water-based paint is more than 0.4MPa, the tensile strength is more than 0.1MPa, and the fireproof grade is A1 grade.

The preparation method of the aerogel precursor of the ultrathin fireproof water-based paint comprises the following steps:

(1) preparation of a mixed solution of a silicon source and a solvent

Putting sodium silicate with the modulus of 3.0-4.0 into a reaction kettle, adding deionized water with the mass of 1-3 times that of the sodium silicate for dilution, stirring the reaction kettle at the speed of 80-200 revolutions per minute for 30 minutes, and filtering the mixture through a 200-mesh sieve to obtain a sodium silicate solution;

the aqueous solution of sodium silicate is commonly called water glass, which is composed of alkali metal and silicon dioxide in different proportions and has the chemical formula R₂O·nSiO₂In the formula, R₂O is an alkali metal oxide, n is the ratio of the number of moles of silica to the number of moles of alkali metal oxide, called the modulus of water glass, most commonly sodium silicate waterglass Na₂O·nSiO₂；

(2) Sol gel

Taking acid A, adding metal salt A and rare earth acid salt A into the acid A, uniformly mixing, and adding into the sodium silicate solution obtained in the step (1) in a spraying manner; rapidly stirring the materials in the reaction kettle at the speed of 1200-2000 rpm while spraying, and controlling the pH value of the sodium silicate solution to be 1.5-3.0 to obtain sol;

(3) gel

Taking sodium hydroxide or ammonia water, adding deionized water to dilute until the pH value is 10-11.5, and adding the sodium hydroxide or ammonia water into a reaction kettle in a spraying manner; rapidly stirring the materials in the reaction kettle at the speed of 1200-2000 rpm while spraying, and stopping spraying when the pH value of the materials in the reaction kettle is 4.5-5.5 to obtain gel; in the prior art, the aging is generally carried out in a standing mode, the time is consumed for 3-5 days, and the gel is not stirred, because the aging process is generally considered to be required to be carried out in the prior art, and the structural growth of the aerogel can be facilitated by standing;

(4) aging of

Continuously stirring the mixture in the reaction kettle for 3 to 10 hours at the speed of 20 to 50 revolutions per minute, aging the materials in the reaction kettle, and controlling the temperature of the materials in the reaction kettle to be 35 to 50 ℃;

(5) solvent replacement

Continuously stirring in the reaction kettle for 60-180 minutes, and simultaneously adding a displacement solvent with the same volume as the aged material in the reaction kettle in the step (4) to displace the residual water;

(6) surface modification

Continuously stirring in the reaction kettle, and simultaneously continuously adding the coupling agent B with the same volume as the aged material in the reaction kettle in the step (4); stirring for 60-180 minutes to obtain the aerogel precursor coated with the replacement solvent and the coupling agent B. The coupling agent B added in the surface modification step (6) replaces water in the aerogel micropores, and the coupling agent B is filled in the gas inlet gel micropores, so that the stability of the micropore structure can be improved, and the average of the pore size is improved; in addition, the hydrophobic and hydrophilic functions of the aerogel can be adjusted by adding different coupling agents B for surface modification.

The aerogel precursor produced by the normal temperature and pressure process is a light porous amorphous inorganic nano material with a controllable structure, has a continuous three-dimensional reticular structure, has the porosity of more than 80 percent, the average pore diameter of about 20nm, the specific surface area of more than 500 square meters per gram and the density of less than 70kg/m³The thermal conductivity coefficient is less than 0.020W/(m.K) at normal temperature and normal pressure, and is lower than the thermal conductivity of 0.022W/(m.K) of static air, so that the material is an inexhaustible solid material with low cost, industrialization and low thermal conductivity.

In the step (2), the acid A is sulfuric acid, hydrochloric acid, oxalic acid or nitric acid, and is adjusted to 6-15mol/L by deionized water; the metal salt A is zirconium salt A or aluminum salt A; the rare earth A acid salt is cerium salt A, yttrium salt A or lanthanum salt A;

in the step (2), the molar ratio of the metal salt A to the rare earth A acid salt is 100:1-6 calculated by oxide; the mole ratio of the oxide of the metal salt A to the silicon oxide in the sodium silicate is 2-5: 100; the metal salt A and the rare earth A acid salt are liable to absorb moisture and cause inaccurate metering, so that in order to accurately quantify the amounts to be added, the metal salt A and the rare earth A acid salt are added in a molar ratio of 100: 1-6; in the step (2), the mole ratio of the oxide of the metal salt A to the silicon oxide in the sodium silicate is 2-5:100, respectively; for example, the metal salt A is aluminum sulfate, and calculated by oxides thereof, namely, the molar ratio of the aluminum oxide to the silicon oxide in the sodium silicate is 2-5:100, respectively;

in the step (5), the replacement solvent is one or a mixture of methanol, acetone, n-hexane or heptane; the stirring in the step (5) or the step (6) is to provide rapid forward stirring in the center of the reaction kettle, and baffle plates are provided at the periphery of the center of the reaction kettle;

in the step (6), the coupling agent B is one or a mixture of hexamethyldisilazane, bis (trimethylsilyl) acetamide, methoxytrimethylsilane, dimethoxydimethylsilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane and methyltrimethoxysilane.

The ultrathin fireproof water-based paint comprises the following steps:

(1) preparation of component A:

adding other solid components except the aerogel precursor in the component A into a sand mill together, grinding, sieving, adding the sieved powder and the aerogel precursor into a planetary grinder, adding water into a kneader, and kneading to obtain a component A;

(2) preparation of component B:

uniformly stirring the silica sol and the organic silicon modified acrylic emulsion, adding the rest components, uniformly stirring, adding 10-60 parts by weight of sodium water glass, 10-60 parts by weight of potassium water glass, 30-90 parts by weight of water, 5-40 parts by weight of silica sol, 1-15 parts by weight of aluminum phosphate and 1-10 parts by weight of coupling agent A, adding the components into a sand mill, and grinding to prepare a component B;

(3) and uniformly stirring the component A and the component B at a high speed to prepare mixed slurry, circularly grinding the mixed slurry by a sand mill for 20-40 minutes to prepare the ultrathin fireproof water-based paint.

The ultrathin fireproof water-based paint is characterized in that the grinding ball of the sand mill is a zirconium ball with the diameter of 0.8-2 mm; the sieving refers to passing through a stainless steel sieve, and the mesh number of the stainless steel sieve is 100-300 meshes;

the grinding time of the component A in the planetary grinding machine is 20-60min, the grinding speed of the main shaft is 50-200rpm, and the grinding speed of the auxiliary shaft is 200-800 rpm;

the rotation speed of the kneader is 50-200rpm, and the kneading time is 30-80 min;

the high-speed stirring speed is 500-1200rpm, and the high-speed stirring time is 30-60 min;

the grinding speed of the mixed slurry in a sand mill is 50-200rpm, and the grinding time is 20-80 min.

The working principle of the invention is as follows:

aerogels, also known as blue smoke, have the following properties: 1. the inside of the aerogel is distributed with a plurality of infinite nano holes and air hole walls, air can not flow freely in the nano holes and is relatively adsorbed on the air hole walls, the aerogel material is in a state similar to vacuum, convection heat transfer is effectively reduced, and heat can be transferred along the air hole walls when being transferred in the solid material; these porous walls constitute an infinitely long heat conduction path, which will significantly reduce heat conduction; 2. infinite air hole walls exist in the aerogel, and the air hole walls are equivalent to infinite heat insulation baffles, so that light and heat can be reflected, and radiation heat transfer is greatly reduced; 3. the aerogel can effectively penetrate through sunlight and prevent infrared heat radiation of the ambient temperature, and becomes an ideal transparent heat-insulating material, so that the heat conductivity of the material is greatly reduced;

based on the characteristics of the aerogel, the aerogel is added into the coating matrix to prepare the fireproof coating, so that the mechanical strength of the fireproof coating can be enhanced, the heat conductivity coefficient of the fireproof coating can be effectively reduced, the heat preservation and insulation capacity of the fireproof coating is improved, and the hydrophobic rate is improved.

The invention has the beneficial effects that:

1. according to the invention, materials such as silica sol, organic silicon modified acrylic emulsion and the like are selected as a bonding agent, an aerogel precursor is used as a core raw material, and the water-based fireproof coating is prepared;

2. the aerogel in the invention is added in the form of an aerogel precursor, and the drying treatment step is not carried out, so that the production cost is low; in addition, the aerogel precursor is prepared at normal temperature and normal pressure, the process is simple and stable, the safety is high, the process is reduced from the traditional 300h to 30h, the investment of a production device with the same energy production is only 1/20 of the traditional method, the price of raw materials is over 100 times lower than that of a traditional silicon source, and the product cost is only 1/10 of the traditional method;

3. the fireproof coating realizes the fireproof A1 grade, and the fireproof performance is obviously improved; when the fireproof coating is coated on steel, the fireproof coating can prevent fire for one hour at 300 ℃ under the condition that the thickness of the coating is 0.3 mm; in the case of a coating thickness of 3mm, fire protection can be carried out for three hours at 600 ℃ and, in the case of a coating thickness of 6mm, at 1000 ℃ for three hours.

4. The working principle of the aerogel precursor preparation in the invention is as follows: in the preparation method of the aerogel precursor, the metal salt A and the rare earth A acid salt are added in the gelling process, so that the effects of toughening and improving the heat resistance of the silica aerogel can be achieved; the aging and solvent replacement steps are carried out under the stirring state, so that the reaction efficiency is greatly improved, the process time is shortened, and the method is suitable for industrialization;

5. compared with the prior art, the preparation method of the aerogel precursor has the following advantages:

(1) in recent years, some related reports and patent documents about aerogel preparation under normal temperature and differential pressure exist in the prior art, but most of the reports and patent documents stay in a laboratory preparation stage, the process is long, and the process implementation range is too narrow, so that large-scale industrial production and application are difficult to realize; the invention provides a preparation method under normal temperature and normal pressure, which changes the relative static process in the prior art, applies stirring in the key process, accelerates the realization of hydrolysis, polycondensation and modification of aerogel, realizes the process of synthesizing aerogel precursor within 30h, provides a method for industrially preparing rare earth toughening aerogel in batches, and provides a premise for mass production and use of aerogel;

(2) one of the reasons for hindering the development of the aerogel in the prior art is that the aerogel has a net-shaped structure, but the structure has thin and fragile edges, low compressive strength and easy collapse under pressure, so that the performance is unstable; according to the invention, rare earth A acid salt and A metal salt are added, so that the toughness of the material is improved, and the strength of the aerogel is improved;

(3) the aerogel prepared by the prior art has low use temperature, is generally stable when used below 500 ℃, and can cause the change of the internal structure of the aerogel above 500 ℃ to reduce the heat conductivity coefficient; according to the invention, rare earth A acid salt and A metal salt are added, so that the temperature resistance of the material is improved, and the heat resistance temperature of the aerogel is increased.

6. The three-dimensional structure of the aerogel precursor plays an important role in the performance exertion process, and the three-dimensional structure cannot play a role if the holes in the aerogel precursor are blocked by the binding agent;

the traditional aerogel is prepared under high temperature and high pressure, if special treatment is not carried out in the later stage, the porous three-dimensional space is easily blocked by a binder or other raw materials to lose the heat insulation effect, in addition, the porous three-dimensional space of the aerogel is combined together to play a better heat insulation effect, and the three-dimensional space in the aerogel is cut into an island after being separated by the binder, so that the island effect is generated, and the heat insulation effect of the aerogel is reduced;

the aerogel precursor prepared by the method contains the displacement solvent, the displacement solvent occupies a porous three-dimensional space in the aerogel precursor, the binder or other raw materials cannot intrude into the porous space to occupy the three-dimensional space, the displacement solvent volatilizes in the drying process of the insulation board, and the porous three-dimensional structure can still be kept in the aerogel after the solvent is volatilized, so that the failure and the island effect caused by hole blockage are overcome, and the heat insulation performance is stronger.

In conclusion, compared with the traditional material, the product has the advantages of obviously reduced coefficient of heat conductivity and thermal coefficient, realization of A1-grade fire prevention, higher mechanical strength, better water resistance and low cost.

Detailed Description

The invention will be further illustrated with reference to specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Example 1

The preparation method of the silicon aerogel precursor comprises the following steps:

(1) preparation of a mixed solution of a silicon source and a solvent

And (3) filling the water glass with the modulus of 3.0 into a reaction kettle, diluting with deionized water with the mass of 2.5 times, stirring for 30 minutes at 180 revolutions per minute, and filtering through a 200-mesh sieve to obtain the water glass solution.

(2) Sol gel

Taking 8mol/L sulfuric acid, and adding zirconium sulfate salt (the molar ratio of the zirconium sulfate salt to the silicon oxide of the water glass solution is 5:100 in terms of zirconium oxide) and yttrium sulfate salt (the molar ratio of the yttrium sulfate salt to the aluminum oxide is 1:100 in terms of yttrium oxide); after uniform mixing, spraying and adding the water glass solution obtained in the step (1), rapidly stirring at 1300 rpm while spraying, stopping spraying when the pH value is controlled to be 1.5, and controlling the spraying time to be 100 minutes; a sol is obtained.

(3) Gel

And (3) spraying a sodium hydroxide solution with the pH value of 11, adding the sodium hydroxide solution into the sol obtained in the step (2), rapidly stirring at 1300 rpm while spraying, stopping spraying until the pH value is 5, and taking 120 minutes to obtain the gel.

(4) Aging of

The gel is continuously stirred for 10 hours in the reaction kettle at the speed of 40 r/min, and the temperature of the gel in the reaction kettle is controlled to be 45 ℃.

(5) Solvent replacement

And adding a replacement solvent n-hexane with the same volume as the aged material while stirring in the reaction kettle, and stirring for 2 hours.

(6) Surface modification

Adding a coupling agent with the same volume as the aged material into the reaction kettle; the coupling agent is dimethoxy dimethyl silane, and the silica aerogel precursor coated with the replacement solvent and the coupling agent is obtained after stirring for 150 minutes and surface modification.

The preparation method of the solid silicon aerogel comprises the following steps: and (2) performing microwave vacuum drying on the silicon aerogel precursor coated with the replacement solvent and the coupling agent, wherein nitrogen in a drying kettle is used for removing oxygen until the oxygen content is less than 3%, the negative pressure is 0.08MPa, the temperature is 95 ℃, the microwave frequency is controlled within the range of 2450MHZ +/-10 MHZ, and the toughened silicon aerogel solid powder is obtained in 55 minutes.

The product has the average pore diameter of 26nm, the specific surface area of 588 square meters per gram and the loose specific gravity of 0.057g/cm³Super-hydrophobic, flame-retardant, heat conductivity coefficient 0.021W/M.K, heat-resisting temperature 880 deg.C, and compressive strength 0.118 MPa.

Example 2

(1) preparation of a mixed solution of a silicon source and a solvent

And (3) putting water glass with the modulus of 3.2 into a reaction kettle, diluting with deionized water with the mass of 3 times, stirring for 30 minutes at 200 revolutions per minute, and filtering through a 200-mesh sieve to obtain a water glass solution.

(2) Sol gel

Taking 10mol/L nitric acid, and adding aluminum salt hydrochloride (the molar ratio of aluminum oxide to silicon oxide in the water glass solution is 2:100 in terms of aluminum oxide) and lanthanum salt hydrochloride (the molar ratio of lanthanum salt hydrochloride to aluminum oxide is 3:100 in terms of lanthanum oxide); after uniform mixing, spraying and adding the mixture into the water glass solution obtained in the step (1), rapidly stirring at 1200rpm while spraying, and controlling the pH value to 2.5, wherein the spraying time is controlled to be 100 minutes; a sol is obtained.

(3) Gel

And (3) spraying an ammonia water solution with the pH value of 10.5, adding the ammonia water solution into the sol obtained in the step (2), rapidly stirring at 1200rpm while spraying, stopping spraying until the pH value is 4.5, and taking 150 minutes to obtain gel.

(4) Aging of

Continuously stirring the reaction kettle for 5 hours at the speed of 30 r/min, and controlling the temperature of gel in the reaction kettle to be 50 ℃;

(5) solvent replacement

While stirring in the reaction kettle, the displacement solvent methanol with the same volume as the aged material is added to displace the residual moisture.

(6) Surface modification

Adding a coupling agent with the same volume as the aged material into the reaction kettle; the coupling agent is vinyl trimethoxy silane, and the surface of the vinyl trimethoxy silane is modified by stirring for 100 minutes to obtain a silicon aerogel precursor coated with a replacement solvent and the coupling agent.

The preparation method of the solid silicon aerogel comprises the following steps: and (2) performing microwave vacuum drying on the silicon aerogel precursor coated with the replacement solvent and the coupling agent, wherein nitrogen in a drying kettle is used for removing oxygen until the oxygen content is less than 2%, the negative pressure is 0.09MPa, the temperature is 110 ℃, the microwave frequency is controlled within the range of 2450MHZ +/-10 MHZ, and the toughened silicon aerogel solid powder is obtained in 50 minutes.

The product has the average pore diameter of 28nm, the specific surface area of 568 square meters/g and the loose specific gravity of 0.056g/cm³Super-hydrophobic, flame-retardant, thermal conductivity 0.0198W/M.K, heat-resisting temperature 920 ℃, and compressive strength 0.122 MPa.

Example 3

(1) preparation of a mixed solution of a silicon source and a solvent

And (3) putting the water glass with the modulus of 4.0 into a reaction kettle, diluting the water glass with deionized water with the mass of 3 times, stirring the mixture for 30 minutes at 80 revolutions per minute, and filtering the mixture through a 200-mesh sieve to obtain the water glass solution.

(2) Sol gel

Adding 15mol/L nitric acid into aluminum oxalate salt (calculated by alumina, the molar ratio of the aluminum oxalate salt to the silicon oxide in the water glass solution is 3:100) and lanthanum oxalate salt (calculated by lanthanum oxide, the molar ratio of the lanthanum oxalate salt to the aluminum oxide is 6: 100); after uniform mixing, spraying and adding the mixture into the water glass solution obtained in the step (1), rapidly stirring at the speed of 1800 rpm while spraying, controlling the pH value to 2.5, and controlling the spraying time to be 100 minutes; a sol is obtained.

(3) Gel

And (3) spraying a sodium hydroxide solution with the pH value of 11.5, adding the sodium hydroxide solution into the sol obtained in the step (2), rapidly stirring at 1200rpm while spraying, stopping spraying until the pH value is 5.5, and taking 80 minutes to obtain the gel.

(4) Aging of

Continuously stirring the reaction kettle for 5 hours at the speed of 50 revolutions per minute, and controlling the temperature of gel in the reaction kettle to be 35 ℃;

(5) solvent replacement

While stirring in the reaction kettle, adding a displacement solvent acetone with the same volume as the aged material to displace the residual water.

(6) Surface modification

Adding a coupling agent with the same volume as the aged material into the reaction kettle; the coupling agent is a mixture of hexamethyldisilazane, bis (trimethylsilyl) acetamide and methoxytrimethylsilane, the weight of which is one third of that of hexamethyldisilazane, the mixture is stirred for 180 minutes, and the surface of the mixture is modified to obtain the silica aerogel precursor coated with the replacement solvent and the coupling agent.

The preparation method of the solid silicon aerogel comprises the following steps: and (2) performing microwave vacuum drying on the silicon aerogel precursor coated with the replacement solvent and the coupling agent, wherein nitrogen in a drying kettle is used for removing oxygen until the oxygen content is less than 1%, the negative pressure is 0.12MPa, the temperature is 80 ℃, the microwave frequency is controlled within the range of 2450MHZ +/-10 MHZ, and the toughened silicon aerogel solid powder is obtained after 60 minutes.

The product has the average pore diameter of 27nm, the specific surface area of 575 square meters/g and the loose specific gravity of 0.058g/cm³Super-hydrophobic, flame-retardant, thermal conductivity 0.0202W/M.K, and heat-resisting temp725 ℃ and the compressive strength of 0.125 MPa.

Example 4

(1) preparation of a mixed solution of a silicon source and a solvent

And (3) putting the water glass with the modulus of 3.5 into a reaction kettle, diluting with deionized water with the mass of 2.5 times, stirring for 30 minutes at 120 revolutions per minute, and filtering through a 200-mesh sieve to obtain the water glass solution.

(2) Sol gel

Taking 6mol/L nitric acid, adding zirconium nitrate salt (calculated by zirconia, the molar ratio of the zirconium nitrate salt to the silicon oxide in the water glass solution is 4:100) and cerium nitrate salt (calculated by cerium oxide, the molar ratio of the cerium nitrate salt to the zirconium oxide is 4: 100); after uniform mixing, spraying and adding the mixture into the water glass solution obtained in the step (1), rapidly stirring at the speed of 2000 rpm while spraying, controlling the pH value to be 5, and controlling the spraying time to be 120 minutes; a sol is obtained.

(3) Gel

And (3) spraying an ammonia water solution with the pH value of 10.5, adding the ammonia water solution into the sol obtained in the step (2), rapidly stirring at 1300 rpm while spraying, stopping spraying until the pH value is 4.5, and taking 180 minutes to obtain the gel.

(4) Aging of

Continuously stirring the reaction kettle for 8 hours at the speed of 20 r/min, and controlling the temperature of gel in the reaction kettle to be 40 ℃;

(5) solvent replacement

The displacement solvent (acetone, n-hexane and heptane, one third by weight of a mixture) was added in the same volume as the aged material while stirring in the reaction kettle to displace the remaining water.

(6) Surface modification

Adding a coupling agent with the same volume as the aged material into the reaction kettle; the coupling agent is a mixture of phenyltriethoxysilane, phenyltrimethoxysilane and methyltrimethoxysilane, the weight of which is one third of that of the mixture, and the mixture is stirred for 60 minutes to obtain the silicon aerogel precursor coated with the replacement solvent and the coupling agent after surface modification.

The preparation method of the solid silicon aerogel comprises the following steps: and (2) performing microwave vacuum drying on the silicon aerogel precursor coated with the replacement solvent and the coupling agent, wherein nitrogen in a drying kettle is used for removing oxygen until the oxygen content is less than 3%, the negative pressure is 0.10MPa, the temperature is 100 ℃, the microwave frequency is controlled within the range of 2450MHZ +/-10 MHZ, and the toughened silicon aerogel solid powder is obtained within 30 minutes.

The product has the average pore diameter of 24nm, the specific surface area of 558 square meters per gram and the loose specific gravity of 0.061g/cm through detection³Super-hydrophobic, flame-retardant, heat conductivity coefficient of 0.0196W/M.K, heat resistance temperature of 729 ℃ and compressive strength of 0.121 MPa.

Examples 5 to 11

the component A comprises an aerogel precursor, kaolin, cordierite, ash calcium powder, diatomite, closed-cell perlite, ceramic fiber, titanium dioxide, wollastonite powder, mullite, heavy calcium material and alumina in parts by weight;

the component B comprises, by weight, 10-60 parts of sodium water glass, 10-60 parts of potassium water glass, 30-90 parts of water, 5-40 parts of silica sol, 1-15 parts of aluminum phosphate, 1-10 parts of coupling agent A, 1-15 parts of film forming additive, 5-30 parts of bentonite, 1-15 parts of organosilicon modified acrylic emulsion, 1-8 parts of flatting agent and 1-8 parts of film forming agent. The components of the ultra-thin fire-retardant water-based paint of examples 5-11 are shown in tables 1-3:

table 1 shows the details of the components of the ultra-thin fire-retardant aqueous coating compositions of examples 5 to 11

Table 2 shows the particle size or fiber length of component A in the ultra-thin fire-retardant water-based paint of examples 5 to 11

Table 3 shows the specific substances of the leveling agent, the coupling agent A, the film forming agent and the film forming aid in the component B of the ultra-thin fireproof water-based paint of examples 5-11

The ultrathin fireproof water-based paint comprises the following steps:

(1) preparation of component A:

(2) preparation of component B:

uniformly stirring the silica sol and the organic silicon modified acrylic emulsion, adding the rest components, and uniformly stirring to prepare a component B;

(3) and uniformly stirring the component A and the component B at a high speed to prepare mixed slurry, and circularly grinding the mixed slurry through a sand mill to prepare the ultrathin fireproof water-based paint.

Wherein, the grinding ball of the sand mill is a zirconium ball with the diameter of 0.8-2 mm; the sieving refers to passing through a stainless steel sieve, and the mesh number of the stainless steel sieve is 100-300 meshes;

the grinding time of the component A in the planetary grinding machine is 20-60min, the grinding speed of the main shaft is 50-200rpm, and the grinding speed of the auxiliary shaft is 200-800 rpm; the rotation speed of the kneader is 50-200rpm, and the kneading time is 30-80 min; the high-speed stirring speed is 500-1200rpm, and the high-speed stirring time is 30-60 min; the grinding speed of the mixed slurry in a sand mill is 50-200rpm, and the grinding time is 20-80 min. The ultra-thin fire-retardant water-based paint of examples 5 to 11 is shown in Table 4.

TABLE 4 ultra-thin, fire-retardant, aqueous coating compositions of examples 5-11

Second, performance detection

The product is detected according to GB/T9755-2014 synthetic resin emulsion exterior wall paint, and specific detection results are shown in Table 5.

Table 5 shows the results of the products of examples 5 to 11, which were tested according to GB/T9755-2014 synthetic resin emulsion exterior wall coatings

Testing the mechanical property of the product according to HG/T4758-2014, and detecting the combustion performance of the product of the embodiment 5-11 according to a method specified in GB8624-2012 'grading of combustion performance of building materials and products'; the results are shown in Table 6.

TABLE 6 mechanical and fire-retardant Properties of the products of examples 5 to 11 according to the invention

Claims

1. An ultrathin fireproof water-based paint is characterized in that: the water-based paint comprises a component A and a component B; the weight part ratio of the component A to the component B is 0.5-1.5: 1;

the component A comprises, by weight, 30-70 parts of aerogel precursor, 3-15 parts of kaolin, 5-20 parts of cordierite, 8-25 parts of sierozem powder, 2-10 parts of diatomite, 2-10 parts of closed-cell perlite, 1-8 parts of ceramic fiber, 1-10 parts of titanium dioxide, 1-10 parts of wollastonite powder, 5-15 parts of mullite, 0.5-10 parts of heavy calcium material and 0.5-8 parts of alumina;

the component B comprises, by weight, 10-60 parts of sodium water glass, 10-60 parts of potassium water glass, 30-90 parts of water, 5-40 parts of silica sol, 1-15 parts of aluminum phosphate, 1-10 parts of coupling agent A, 1-15 parts of film forming additive, 5-30 parts of bentonite, 1-15 parts of organosilicon modified acrylic emulsion, 1-8 parts of flatting agent and 1-8 parts of film forming agent;

the preparation method of the aerogel precursor comprises the following steps:

(1) preparation of a mixed solution of a silicon source and a solvent

(2) sol gel

Taking acid A, adding metal salt A and rare earth acid salt A into the acid A, uniformly mixing, and adding into the sodium silicate solution obtained in the step (1) in a spraying manner; rapidly stirring the materials in the reaction kettle at the speed of 1200-2000 rpm while spraying, and controlling the pH value of the sodium silicate solution to be 1.5-3.0 to obtain sol; in the step (2), the acid A is sulfuric acid, hydrochloric acid, oxalic acid or nitric acid, and is adjusted to 6-15mol/L by deionized water; the metal salt A is zirconium salt A or aluminum salt A; the rare earth A acid salt is cerium salt A, yttrium salt A or lanthanum salt A;

(3) gel

Taking sodium hydroxide or ammonia water, adding deionized water to dilute until the pH value is 10-11.5, and adding the sodium hydroxide or ammonia water into a reaction kettle in a spraying manner; rapidly stirring the materials in the reaction kettle at the speed of 1200-2000 rpm while spraying, and stopping spraying when the pH value of the materials in the reaction kettle is 4.5-5.5 to obtain gel;

(4) aging of

(5) solvent replacement

(6) surface modification

Continuously stirring in the reaction kettle, and simultaneously continuously adding the coupling agent B with the same volume as the aged material in the reaction kettle in the step (4); stirring for 60-180 minutes to obtain an aerogel precursor coated with a displacement solvent and a coupling agent B;

the leveling agent is a polyether siloxane leveling agent;

the film forming assistant is ethylene glycol, propylene glycol, dodecyl alcohol ester or ethylene glycol butyl ether acetate.

2. The ultra-thin fireproof water-based paint of claim 1, wherein the components A, except the aerogel precursor and the ceramic fiber, are solid powder with a diameter ranging from 0.5mm to 1.5 mm.

3. The ultrathin fireproof aqueous coating of claim 1, wherein in component a, the ceramic fibers have a length of less than 2mm and a diameter of less than 20 μm; the coupling agent A is one or two of KH560 and KH 550;

4. The ultrathin fireproof water-based paint of claim 1, wherein the solid content of the aerogel precursor is 5-35%; the water content of the silica sol is less than or equal to 70 percent, and the solid content of the organic silicon modified acrylic emulsion is more than or equal to 60 percent.

5. The ultrathin fireproof water-based paint of claim 1, wherein in the step (2), the molar ratio of the metal salt A to the rare earth A acid salt A is 100:1-6 calculated as oxide; the mole ratio of the oxide of the metal salt A to the silicon oxide in the sodium silicate is 2-5: 100.

6. The ultra-thin fireproof waterborne coating according to claim 1, wherein in step (5), the replacement solvent is one or more of methanol, acetone, n-hexane or heptane.

7. The ultra-thin fireproof waterborne coating of claim 1, wherein the stirring in step (5) or step (6) is rapid forward stirring in the center of the reaction kettle, and baffles are provided at the periphery of the center of the reaction kettle.

8. The ultra-thin fireproof waterborne coating of claim 1, wherein in step (6), the coupling agent B is one or more of hexamethyldisilazane, bis (trimethylsilyl) acetamide, methoxytrimethylsilane, dimethoxydimethylsilane, phenyltriethoxysilane, phenyltrimethoxysilane, vinyltrimethoxysilane, methyltriethoxysilane, and methyltrimethoxysilane.