WO2017043721A1 - Blanket comprising silica aerogel and manufacturing method therefor - Google Patents

Abstract

The present invention provides a blanket comprising a silica aerogel and a manufacturing method therefor, the blanket comprising: a base material for the blanket; and a silica aerogel and an opacifier, which are located on at least one of the surface and the inside of the base material for the blanket, wherein the opacifier has a secondary particle phase, formed by aggregation of inorganic particles of a primary particle phase, and comprises 1-5 inorganic particles per 1 μm³ unit volume. According to the present invention, the blanket comprising the silica aerogel comprises an opacifier having excellent dispersibility and high surface activity due to chemical etching, and thus the blanket can exhibit excellent thermal insulation, particularly, flame retardancy with excellent thermal insulation at high temperature.

Description

Blanket with silica airgel and preparation method thereof

Citation with Related Applications

This application claims the benefit of priority based on Korean Patent Application No. 2015-0128547, filed on September 10, 2015 and Korean Patent Application No. 2016-0036566, filed on March 28, 2016. The contents are included as part of this specification.

Technical Field

The present invention relates to a blanket containing silica airgel having excellent thermal insulation and flame retardancy and a method for producing the same.

Recently, as industrial technologies are advanced, interest in aerogels having excellent insulating properties is increasing. The aerogels developed so far include organic aerogels such as resorcinol-formaldehyde or melamine-formaldehyde aerogel particles, silica (Silica, SiO ₂ ), alumina (Alumina, Al ₂ O ₃ ), titania (Titania, TiO _2). Or inorganic aerogels containing metal oxides such as carbon (C) aerogels.

Among these, silica airgel is a highly porous material, and has high porosity, specific surface area, and low thermal conductivity, and is expected to be applied in various fields such as insulation, catalyst, sound absorbing material, or interlayer insulating material of semiconductor circuits. have. Although the speed of commercialization is very slow due to complex manufacturing processes and low mechanical strength, the result of continuous research is increasing the speed of market expansion including insulation.

Since silica airgel has a low mechanical strength due to its porous structure, the silica airgel is usually combined with a substrate such as glass fiber, ceramic fiber, or polymer fiber to produce a product such as an airgel blanket or airgel sheet.

However, since the airgel powder is weakly adhered to the base material for the blanket, it is easy to be detached during the work, and the powder is blown off so much that the working environment is highly polluted. In addition, the density and mechanical strength of the airgel itself is very low, it is difficult to commercialize in the form of sheets or boards.

On the other hand, in order to maximize the effect as a heat insulating material, in particular, a high temperature heat insulating material in the manufacture of a blanket containing silica airgel has been used an opacifying agent having an absorption ability to the wavelength of the infrared (IR) region at a high temperature.

However, in the case of the conventional opacifier, since the particle size is large, there is a problem in that dispersibility is low and precipitates quickly. In order to solve this problem, a method of increasing the dispersibility of the opacity agent in a synthetic reaction system using various kinds of dispersants has been proposed, but since the dispersant is mostly composed of organic substances, the flame retardant performance of the blanket produced silica aerogel-containing blanket is reduced, There is also a problem of generating dust.

In addition, since the conventional opaque agent has a low surface activity of particles and thus is not easy to chemically bond with the silica precursor, the content of the opaque agent in the blanket to be produced is significantly low, so that the effect of improving the thermal insulation performance by using the opaque agent is improved. It was not big.

It is an object of the present invention to provide a blanket containing silica airgel having excellent heat insulation and flame retardancy, and a method of manufacturing the same.

Another object of the present invention to provide a heat insulating material prepared using the blanket containing the silica airgel.

Another object of the present invention is to provide a dispersion comprising an opaque agent, which is useful for preparing the blanket containing silica airgel.

In order to solve the above problems, according to an embodiment of the present invention a substrate for a blanket; And a silica aerogel and an opacifying agent, which are located on at least one of the surface and the inside of the blanket substrate, wherein the opacifying agent is a secondary particle in which inorganic particles on the primary particles are aggregated, and 1 per ³ μm of volume. Provided is a blanket comprising silica aerogels comprising from five to five inorganic particles.

In addition, according to another embodiment of the present invention, after dispersing the inorganic particles in a basic aqueous solution and etching, adding a water to prepare a dispersion containing an opacifier; Mixing the opacifier-containing dispersion with a silica precursor-containing solution to prepare a composition for opacifier-containing silica airgel formation; Preparing an opacifying agent-silica gel-based composite by adding a base catalyst and a hydrophilic polar organic solvent to the composition for forming the airgel-containing silica airgel, followed by adding and gelling the substrate for the blanket; And it provides a method for producing a blanket comprising a silica airgel comprising the step of drying the opaque agent-silica gel-based complex after hydrophobization surface modification.

According to another embodiment of the present invention provides a heat insulating material prepared using the blanket containing the silica airgel.

In addition, according to another embodiment of the present invention, an opacifying agent and water, wherein the opacifying agent provides a dispersion containing an opaque agent that the average zeta potential in water is -10mV to -60mV.

Blanket containing silica airgel according to the present invention, by including an opaque agent having excellent dispersibility, dispersion stability, and high surface activity through chemical etching, it can exhibit flame retardancy with excellent thermal insulation, in particular excellent thermal insulation at high temperatures have.

The following drawings, which are attached to this specification, illustrate preferred embodiments of the present invention, and together with the contents of the present invention serve to further understand the technical spirit of the present invention, the present invention is limited to the matters described in such drawings. It should not be construed as limited.

1 is a transmission electron microscope (TEM) photograph of the transparent agent prepared in Example 1;

Figure 2 is a TEM photograph of the opaque agent prepared in Comparative Example 1.

3 is a TEM photograph of a blanket containing silica airgel prepared in Example 1. FIG.

FIG. 4 is a TEM photograph of a blanket containing silica airgel prepared in Comparative Example 1. FIG.

5 is a graph illustrating the change of the average particle diameter and the average zeta potential of the opaque agent according to the content of KOH during the preparation of the opaque agent.

6 is a graph illustrating a particle size distribution of an opaque agent according to etching in Experimental Example 2. FIG.

Figure 7 is a photograph observing the change in dispersibility with time of the composition for forming an opaque-containing silica airgel prepared in Example 1 and Comparative Example 1 (in Figure 7 a) is just after manufacture, b) is left for 1 hour C) is after 3 hours stationary).

Hereinafter, the present invention will be described in more detail to aid in understanding the present invention.

The terms or words used in this specification and claims are not to be construed as being limited to their ordinary or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best describe their invention. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

In the present invention, when preparing a blanket containing silica airgel using an opaque agent, by reducing the particle size of the opaque agent through the chemical etching while increasing the surface activity, dispersibility and dispersion of the opaque agent in the reaction system without using a dispersant Increasing the stability and at the same time increasing the surface activity significantly can improve the thermal insulation of the blanket during the production of the blanket, in particular at high temperatures and flame retardancy.

That is, a blanket containing silica airgel according to an embodiment of the present invention, the blanket base material; And a silica airgel and an opaque agent disposed on at least one of the surface and the inside of the blanket substrate, wherein the opaque agent is a secondary particle in which inorganic particles on the primary particle are aggregated, and per 1 μm ³ unit volume. It contains 1 to 5 inorganic particles.

In the present invention, "primary particle" or "primary particle" means a single particle, and "secondary particle" or "secondary particle" means that two or more primary particles are physically and / or chemically bonded. It refers to a structure that is aggregated through to form a relatively large particle form.

In the present invention, the number of inorganic particles per unit volume is an average value.

Specifically, in the blanket containing silica airgel, the opacifying agent is prepared by chemically etching the inorganic particles using a strong base. At this time, the zeta potential at the particle size and the surface can be controlled by controlling the concentration of the base for etching and the etching process time. In the present invention, excellent dispersion and dispersion stability can be exhibited in the manufacture of a blanket containing silica airgel. By controlling the etching process so that the opacifying agent used in the present invention is smaller in size and uniform in size than the conventionally used opacifying agent. In addition, it has a high surface activity and can exhibit excellent bonding to substrates for silica aerogels and blankets.

Specifically, the preparation of the blanket containing silica airgel according to an embodiment of the present invention is carried out under hydrophilic conditions such as using water as a solvent. If the size of the inorganic particles becomes too large under such hydrophilic conditions, precipitation tends to occur due to the density of the inorganic particles themselves. In addition, the zeta potential on the surface of the inorganic particle, regardless of whether it is positive or negative, means that a large number of functional groups on the surface of the particle are distributed, and as a result, it may exhibit better dispersibility. As such, when the inorganic particles are uniformly dispersed by controlling the size of the inorganic particles and the surface zeta potential, a reaction such as a condensation reaction with the silica precursor may be uniform and more efficient.

More specifically, the opacifying agent may have an average zeta potential of -10 mV to -60 mV in water as a dispersion medium.

In the present invention, "zeta potential" is an index indicating the amount of surface charge of colloidal particles suspended in a liquid. When an electric field is applied to the colloid from the outside, the colloidal particles move in a direction opposite to the sign of the surface potential. The particle velocity is calculated by considering the applied electric field strength and hydrodynamic effects (solvent viscosity, dielectric constant, etc.). That is, the greater the absolute value of the zeta potential, the stronger the repulsive force between the particles, the higher the dispersion and dispersion stability. On the contrary, when the zeta potential approaches zero, the particles tend to aggregate.

The opacifying agent included in the silica airgel-containing blanket in the present invention includes various surface functional groups, specifically condensation-reactive functional groups, on the surface by an etching process, and as a result shows an average zeta potential in the above range. The average zeta potential of the opaque agent can be controlled by controlling the concentration of the strong base during the etching process and the etching time, and in the present invention, by having the average zeta potential in the above range, excellent dispersibility and dispersion stability in the reaction system for blanket production Can be represented. As a result, when the blanket is manufactured, it can be uniformly dispersed in a higher content on the surface and inside of the blanket, thereby exhibiting excellent IR absorption ability throughout the blanket, and can also exhibit a markedly improved thermal insulation. Considering the remarkable effect of the improvement effect according to the zeta potential control of the opacifier, the average zeta potential in water may be more specifically -30 mV to -60 mV, and even more specifically -50 mV to -60 mV Can be.

In addition, the opacifying agent may exhibit high reaction activity by forming a reactive functional group on the surface of the particle by the strong base treatment in the manufacturing process as described above. Specifically, the inorganic particles constituting the opacifying agent include a condensation-reactive functional group capable of easily condensation reaction with the silica precursor on the particle surface. Specifically, the condensation-reactive functional group may be a hydroxy group (-OH), an alkoxy group (-ROH), a carboxy group (-COOH) or an ester group (-COOR), and the like, and may include any one or two or more thereof. Wherein R in the alkoxy group and ester group is each independently an alkyl group having 1 to 20 carbon atoms, a cycloalkyl group having 3 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an arylalkyl group having 7 to 20 carbon atoms, or 7 to 20 carbon atoms. And hydrocarbon groups such as alkylaryl groups.

By condensation reaction with the silica precursor by the condensation-reactive functional groups formed on the surface of the inorganic particles easily and chemically bonded, it is possible to exhibit an excellent binding force to the silica airgel and the substrate for the blanket in the blanket prepared silica aerogel, resulting in Blanc The content of the opacifying agent in the jacket is increased, the true density of the blanket is increased, and the thermal insulation of the blanket can be further improved.

In addition, the opacifying agent may have a simpler structure and smaller particle diameter than the conventional one by the chemical etching process described above.

Usually, the opacifying agent has a secondary particulate form in which a plurality of inorganic particles on the primary particles are aggregated as a unit binder. The structure of the opacifying agent may be defined as the number of particles of the unit binder contained in the unit volume or the weight per unit volume, and closely affects the properties of the opacifying agent together with the particle diameter. As the structure of the opaque agent is developed, the surface area is reduced, and when the structure is less, the density of the unit binder is high and the distance between the unit binders is shortened, which requires a strong dispersion energy.

As the opaque agent used in the present invention is broken through such an etching process, the number of particles of the unit conjugate per unit volume is reduced and simple structuring compared to the conventional opaque agent. Specifically, the opacifying agent used in the present invention includes 1 to 5, more specifically 2 to 5, even more specifically 3 to 5 inorganic particles per 1 μm ³ unit volume.

In addition, the average particle diameter (D ₅₀ ) of the opaque agent may be 300nm to 1600nm under the conditions satisfying the above-described structuring conditions.

If the average particle size of the opacifying agent is less than 300 nm, there is a fear of a decrease in dispersibility due to intergranular aggregation, and if it exceeds 1600 nm, there is a fear of a decrease in its dispersibility. Considering the effect of improving the dispersibility and dispersion stability according to the control of the average particle diameter of the opaque agent, the average particle diameter (D ₅₀ ) of the opaque agent may be 300nm to 600nm.

In the present invention, the average particle diameter (D ₅₀ ) of the opacifying agent may be defined as the particle size at 50% of the particle size distribution. In the present invention, the mean particle diameter (D ₅₀ ) of the opaque agent is, for example, an electron microscope using a scanning electron microscopy (SEM) or a field emission scanning electron microscopy (FE-SEM) or the like. It can be measured by observation or by using a laser diffraction method. In the measurement by the laser diffraction method, more specifically, after dispersing the opaque agent in the dispersion medium, it is introduced into a commercially available laser diffraction particle size measuring device (e.g., Microtrac MT 3000) to give an ultrasonic wave of about 28 kHz to an output of 60 W. After the irradiation, the average particle diameter D ₅₀ at the 50% reference of the particle diameter distribution in the measuring device can be calculated.

In addition, the inorganic particles on the primary particles constituting the opaque agent have an average particle diameter (D ₅₀ ) of 50nm to 1000nm under the conditions satisfying the number of primary particles per unit volume and the average particle size range of the opaque agent. Can be. If the average particle diameter of the primary particles is less than 50 nm, there is a fear of a decrease in dispersibility due to intergranular aggregation. If the average particle diameter of the primary particles exceeds 1000 nm, there is a concern that the activity of the particle surface is low and the reactivity with the silica network is low. There is. More specifically, the primary particulate inorganic particles may have an average particle diameter of 100nm to 300nm.

On the other hand, in the present invention, the average particle diameter (D ₅₀ ) of the inorganic particles of the primary particle can be defined as the particle size at 50% of the particle size distribution, as defined above, the electron microscope such as TEM for the inorganic particles After the observation, the average particle diameter can be calculated from the results.

In addition, the inorganic particles on the primary particles may include irregularities formed on the surface of the primary particles in addition to the simplification of the structure of forming the secondary particles by the etching process described above. Unevenness on the surface of the primary particles can be confirmed according to a conventional particle surface observation method, specifically, can be observed through a scanning electron microscope or the like.

Moreover, since the said opacifier contains inorganic particle, the flame retardance of a silica airgel containing heat insulating material can be improved.

Specifically, the inorganic particles may include metal oxides such as silica (SiO ₂ ), alumina (Al ₂ O ₃ ), titania (TiO ₂ ), zirconia (ZrO ₂ ), tin oxide (SnO ₂ ), zinc oxide (ZnO), and iron oxide. ; Metal carbides such as beryllium carbide (Be ₂ C), titanium carbide (TiC) or silicon carbide (SiC); Metal nitrides such as vanadium nitride (VN), titanium nitride (TiN), molybdenum nitride (Mo ₂ N), tungsten nitride (TuN), niobium nitride (NbN), titanium nitride (TiN) or boron nitride (BN); Metal hydroxides such as magnesium hydroxide (Mg (OH ₂ )) or aluminum hydroxide (Al (OH) ₃ ); Metal salts such as calcium carbonate (CaCO ₃ ), and the like; Silicate compounds such as Ca ₃ SiO ₅ (tricalcium silicate), Ca ₂ SiO ₄ (dicalcium silicate), CaSiO ₃ (calcium metasilicate), and the like; Graphite such as natural graphite or artificial graphite; Carbon-based materials such as carbon black, acetylene black, ketjen black, channel black, furnace black, lamp black, thermal black and carbon fiber; Yttria stabilized zirconia (YSZ), calcia stabilized zirconia (CSZ), scandia-stabilized zirconia (SSZ), nickel-yttria stabilized zirconia cermet (Ni-YSZ cermet), etc. Such as ceramic particles; Or metal-containing pigments such as iron and manganese, and any one or a mixture of two or more thereof may be used.

Depending on the use of the blanket containing the silica airgel may be appropriately selected from the inorganic particles exemplified above.

Specifically, in the case of a high-temperature blanket having a use temperature range of 0 ° C to 600 ° C and a maximum usable temperature of 650 ° C, the inorganic particles include metal oxides such as titania or iron oxide; Metal hydroxides such as aluminum hydroxide (Al (OH) ₃ ); Iron and manganese-containing pigments and the like may be used, and more specifically, may be titania (TiO ₂ ) which exhibits excellent IR wavelength absorption at high temperatures. In addition, the TiO ₂ may have a rutile type, anatase type, or a mixed crystal structure thereof, and may have a rutile type crystal structure having better IR absorption ability.

In the case of a low temperature blanket having a use temperature range of -200 ° C to 150 ° C, a minimum usable temperature of -200 ° C, and a maximum usable temperature of 200 ° C, the inorganic particles include magnesium hydroxide (Mg (OH _2). ) Or metal hydroxides such as aluminum hydroxide (Al (OH) ₃ ), and the like, more specifically magnesium hydroxide may be used.

In addition, in the case of a blanket for room temperature having a use temperature range of -50 ° C to 200 ° C and a maximum use temperature of 200 ° C, graphite, a carbon-based material, a silicate compound, or a mixture thereof may be used as the inorganic particles.

The opacifying agent may be included in an amount of 10% to 70% by weight based on the total weight of the blanket containing silica airgel. If the content of the opaque agent is less than 10% by weight, the effect of using the opaque agent is insignificant, and if the content of the opaque agent exceeds 70% by weight, there is a fear of performance deterioration as a heat insulating material.

On the other hand, in the blanket with a silica airgel according to an embodiment of the present invention, the silica airgel is a porous porous structure containing a plurality of micropores, nano-size primary particles, specifically, the average particle diameter ( D ₅₀ ) may have a microstructure, that is, a three-dimensional network structure, in which primary particles of 100 nm or less, more specifically, 10 nm to 50 nm are combined to form a network-shaped cluster.

The porous structure of the silica airgel can control the size and density of the pores through the condition control in the manufacturing process. Specifically, the silica airgel may have a porosity of 90% or more and a tap density of 0.04 g / cm ³ to 0.5 g / cm ³ . In addition, the average pore diameter may be 20 nm or less, or 5 nm to 15 nm.

In the present invention, the tap density of the silica airgel can be measured using a tap density meter (TAP-2S, Logan Istruments co.), And the average pore diameter and porosity are measured using a partial pressure (0.11) using an ASAP 2010 instrument from Micrometrics. It can be measured by the adsorption / desorption amount of nitrogen according to <p / p _o <1).

In addition, the silica airgel may have an average particle diameter or specific surface area that can be easily penetrated or adhered to the voids of the substrate for the blanket used in the manufacture of the blanket. Specifically, the silica airgel may have a specific surface area of 700 m ² / g or more, more specifically 700 m ² / g to 1000 m ² / g. When the specific surface area condition is met together with the tap density, the volume occupied by the pores may result in low thermal conductivity and improved thermal insulation effect. The silica airgel may have an average particle diameter (D ₅₀ ) of 10 μm to 80 μm, more specifically 10 μm to 20 μm.

In the present invention, the specific surface area of the silica airgel can be by using a Micrometrics ASAP 2010 instrument of measuring the adsorption / desorption amount of nitrogen according to the partial pressure _{(0.11 <p / p o <} 1). In addition, the average particle diameter (D ₅₀ ) can be defined as the particle size at 50% of the particle size distribution, wherein the average particle diameter of the silica airgel can be measured using a laser diffraction method, more Specifically, the hydrophobic silica airgel is dispersed in a solvent, introduced into a commercially available laser diffraction particle size measuring apparatus (for example, Microtrac MT 3000), irradiated with ultrasonic waves of about 28 kHz at an output of 60 W, and then the particle diameter in the measuring apparatus. The average particle diameter (D ₅₀ ) at 50% of the distribution can be calculated.

In addition, the hydrophobic airgel may have a lower thermal conductivity than the base material for the blanket, which may increase the thermal insulation effect during manufacture of the blanket. Specifically, the silica airgel may have a thermal conductivity of 20 mW / mK or less.

In addition, the silica airgel is a hydrophobic surface treatment.

Normally, silica airgel maintains low thermal conductivity immediately after preparation, but the thermal conductivity gradually increases as the hydrophilic silanol group (Si-OH) present on the silica surface absorbs water in the air. Accordingly, in order to maintain low thermal conductivity, it is necessary to modify the silica airgel surface hydrophobicly. In the normal hydrophobic airgel, the degree of hydrophobicity or the degree of hydrophobicity can be confirmed by the carbon content contained in the hydrophobic airgel. In the present invention, the silica airgel is specifically, based on the total weight of the silica airgel at room temperature (23 ± 5 ° C.). It may have a carbon content of at least weight percent, or 8.5 to 12 weight percent.

Such silica airgel may be included in an amount of 20% to 80% by weight based on the total weight of the blanket containing silica airgel. Insulation increases as the content of the silica airgel in the blanket increases, but if it exceeds 80% by weight, the strength and adhesion in the subsequent blanket production may be deteriorated due to the low strength and adhesion of the silica airgel itself. In addition, when the content of the silica airgel in the blanket is too low, specifically less than 20% by weight there is a fear of lowering the thermal insulation.

Meanwhile, in the blanket containing silica airgel, the blanket base material may be a fiber, a film, a sheet, a net, a fiber, a porous body, a foam, a nonwoven fabric, or a laminate of two or more thereof. . In addition, fine irregularities may be formed or patterned on the surface thereof depending on the intended use. More specifically, the blanket substrate may be a fiber capable of further improving the thermal insulation performance by including a space or a space in which the hydrophobic airgel is easily inserted into the blanket substrate.

In addition, the blanket base material is specifically polyamide, polybenzimidazole, polyaramid, acrylic resin, phenol resin, polyester, polyether ether ketone (PEEK), polyolefin (for example, polyethylene, polypropylene or these Copolymer, etc.), cellulose, carbon, cotton, wool, hemp, nonwoven fabric, glass fiber or ceramic wool, and the like, but is not limited thereto. More specifically, the substrate may include any one or two or more selected from the group consisting of glass fibers, polyethylene, and polyester.

In addition, the blanket base material may have a low thermal conductivity, specifically 20 mW / mk or less, more specifically 15 mW / mk to 20 mW / mk.

In addition, the blanket substrate may be a hydrophobic surface treatment, and thus may further include a hydrophobic surface treatment layer on at least one surface of the blanket substrate.

Hydrophobic treatment of the substrate for the blanket can be carried out according to a conventional method, specifically, a chain-shaped hydrocarbon group, aromatic hydrocarbon group, halogenated alkyl group, organosilicon group, alkyl group, vinyl group, allyl group, aryl group, phenyl group It can be carried out by surface treating the substrate for the blanket using a compound containing a hydrophobic functional group, such as.

In addition, the blanket substrate is preferably low density, specifically, when the substrate is a fiber, the fibers constituting the fiber may have an average fiber diameter of 10㎛ to 30㎛. As such, the low density allows easy introduction of silica aerogels and opacifiers into the blanket substrate, thereby increasing the content of silica aerogels and opacifiers to increase the thermal insulation and at the same time increasing the flexibility of the finished blanket. It can increase.

In addition, the blanket substrate may be partially or entirely formed of a functional layer such as a heat reflection layer for improving heat insulation performance or a surface protection layer capable of improving life characteristics through surface protection.

For example, the heat reflection layer includes a compound capable of reflecting or blocking infrared radiation, and specifically, carbon black, carbon fiber, titanium dioxide, metal (aluminum, stainless steel, copper / zinc alloy, copper / chromium alloy) Etc.), nonmetals, fibers, pigments, and the like. In addition, the surface protective layer may include a high heat-resistant moisture-permeable waterproof material such as polytetrafluoroethylene.

The stacking of the functional layer may be performed by directly forming the functional layer on at least one surface of the insulating blanket, or laminating the functional layer after placing the functional layer. The laminating process may be performed according to conventional methods such as heat treatment or hot rolling treatment.

In the blanket containing silica airgel according to an embodiment of the present invention having the above-described structure and structure, inorganic particles are dispersed and etched in a basic aqueous solution, and then water is added to prepare a dispersion containing an opaque agent (step 1 ); Mixing the opacifier-containing dispersion with a silica precursor to prepare a composition for forming an opacifier-silica aerogel (step 2); Preparing a opaque-silica gel-based composite by adding a base catalyst and a polar organic solvent to the composition for forming an opaque-agent-silica aerogel, and then adding and gelling the substrate for a blanket (step 3); And a step (step 4) of drying the opacifying agent-silica gel-based composite after hydrophobization surface modification. Accordingly, according to another embodiment of the present invention, there is provided a method of manufacturing the blanket containing silica airgel.

Referring to each step below, step 1 for preparing a blanket containing a silica airgel according to an embodiment of the present invention is to prepare a dispersion containing an opacifier.

Specifically, the dispersion containing the opacifier may be prepared by dispersing the inorganic particles in a basic aqueous solution and etching them, and then adding water to the resulting inorganic particles. At this time, a chemical etching reaction occurs on the inorganic particles, and the inorganic particles are as described above.

Since the chemical etching of the inorganic particles is caused only by strong bases, the strong bases that can be used in the preparation of the dispersion containing the opaque agent include 12 or more, more specifically, under high acid dissociation constants, specifically 25 ° C. and 0.1M aqueous solution conditions. Basic materials having an acid dissociation constant (pKa) of 13.5 or more may be used. More specifically, the strong base may include sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, and the like, and any one or a mixture of two or more thereof may be used.

Specifically, the basic aqueous solution is prepared by dissolving the strong base in water, and considering the etching efficiency and fairness, the basic aqueous solution may include the strong base in a concentration of 0.1M to 10M. If the concentration of the basic aqueous solution is less than 0.1M, the etching efficiency for the inorganic particles is low, there is a fear that the preparation of the opacifying agent having the above-described physical properties may not be easy, and if it exceeds 10M it is not easy to control the etching reaction In addition, the pH of the dispersion containing the opacifier may be increased, which may affect silica airgel formation.

The etching reaction to the inorganic particles can be controlled according to the concentration of the strong base used and the time of the etching process. In the present invention, it is possible to appropriately determine the concentration and time of the base so that an opaque agent which realizes the physical properties such as zeta potential and particle size can be prepared. When using the basic aqueous solution described above, the etching time can be appropriately adjusted.

In addition, after completion of the etching process, the etching solution is removed and water is added. At this time, water serves as a dilution solvent for the base material used in etching and as a dispersion medium for the inorganic particles in the dispersion containing the opacifier, and may further act as an etching efficiency enhancer for the inorganic particles.

Alcoholic solvents such as aliphatic glycols, which are conventionally used in the manufacture of blankets containing silica airgel, may also be used, but such aliphatic glycols are simply surface-coated on the surface of the inorganic particles to make the surface of the inorganic particles hydrophilic. It acts as a dispersant to increase the acidity, and since ionization is not easy, it does not provide an effect of improving the etching efficiency for the inorganic particles. On the contrary, since water used in the present invention is easily ionized, the etching efficiency of the strong base with respect to the inorganic particles can be increased, and as a result, the size of the inorganic particles can be easily controlled. In addition, water may increase the activity of the surface of the inorganic particles, thereby increasing the condensation reaction efficiency with the silica precursor.

At this time, the water may be used in an amount such that the content of the opaque agent in the dispersion is 0.1g / 100ml to 3g / 100ml, more specifically 0.4g / 100ml to 2g / 100ml.

In addition, a dispersion process may be further performed to uniformly disperse the inorganic particles in the aqueous solution during the preparation of the dispersion containing the opaque agent, and the dispersion process may be performed by a conventional dispersion treatment such as stirring.

In addition, step 2 for preparing a blanket containing silica airgel according to an embodiment of the present invention, by mixing the opaque agent-containing dispersion prepared in step 1 with the silica precursor, the composition containing the opaque agent-silica airgel formation It is a step to prepare.

The silica precursor may specifically be silica alkoxide or water glass. The silica precursor may be added in a solution phase dissolved in a solvent.

The water glass may be used as a dilution solution prepared by adding and mixing water, specifically distilled water, to the water glass. In the water glass solution, the water glass is not particularly limited, but may specifically include 28 to 35% by weight of silica (SiO ₂ ), the water glass solution diluted by adding water to the water glass is 0.1 weight It may be one containing from 30% by weight of silica.

In addition, the solvent is capable of dissolving the silica precursor, specifically, may be water or a polar organic solvent, and may include any one or a mixture of two or more thereof. In addition, the polar organic solvent may be an alcohol such as ethanol.

The opacifier-containing dispersion and the precursor-containing solution may be mixed in an appropriate mixing ratio in consideration of the content of the opacifier and the silica airgel in the blanket to be prepared, and the content of the opacifier and the silica airgel in the blanket is As described.

 As a result of the above process, a composition for forming an opaque agent-containing silica airgel may be formed.

In addition, step 3 for preparing a blanket containing silica airgel according to an embodiment of the present invention, after the base catalyst and the polar organic solvent is added to the composition containing the opaque-containing silica airgel, the base for the blanket is added And gelation to prepare the opacifier-silica gel-based complex.

The base catalyst serves to promote gelation by increasing the pH in the reaction system, that is, the composition for forming an aerosol-silica aerogel, and specifically, may be ammonia or the like.

The polar organic solvent has excellent miscibility with the silica precursor, and may be uniformly present in the gel during gelation. As a result, the solvent substitution step can be omitted in the preparation of the opaque agent-silica gel-based composite.

Specifically, the polar organic solvent may be an alcohol solvent, and the alcohol solvent may be specifically a monohydric alcohol such as methanol, ethanol, isopropanol, butanol, or the like; Or polyhydric alcohols such as glycerol, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, sorbitol, and the like, and any one or a mixture of two or more thereof may be used. In consideration of the miscibility with water and the uniform dispersibility in silica gel, the alcohol-based compound may be an alcohol having 1 to 8 carbon atoms. In addition to the above effects, when considering the efficiency of the subsequent reforming reaction on the silica surface, the alcohol-based compound may be a linear alcohol having 1 to 4 carbon atoms, such as methanol, ethanol, propanol or n-butanol, 1 of these The species alone or a mixture of two or more thereof may be used. More specifically, the alcohol-based compound may be methanol, ethanol or a mixture thereof.

The base catalyst and the polar organic solvent may be added alone, or may be added in the form of a solution in which the base catalyst is dissolved in the polar organic solvent. In this case, the polar organic solvent may be used in an amount of 5 parts by weight to 20 parts by weight based on 1 part by weight of silica, more specifically 5 parts by weight to 16 parts by weight, and even more specifically 7 parts by weight to 10 parts by weight. Can be used in amounts. In addition, the base catalyst and the base catalyst-containing solution may be added in an amount such that the pH of the composition for forming an opaque-containing silica airgel is 8 to 14, more specifically, pH 8 to 9.

The base catalyst and the polar organic solvent as described above are added to the composition containing the opaque agent-silica aerogel-forming composition to prepare a mixed solution, and the quenching agent-silica gel is induced by immersing or casting the substrate for the blanket in the prepared mixed solution. Prepare the substrate composite. In this case, the blanket base material may be the same as described above.

Next, step 4 for preparing a blanket containing silica airgel according to an embodiment of the present invention, after the hydrophobization surface modification treatment for the opaque agent-silica gel-based composite prepared in step 3, dried to include silica airgel It is a step of manufacturing a blanket.

In this case, an aging process may be optionally further performed before the hydrophobization surface modification treatment.

The aging process is a process for leaving the opacifier-silica gel-based composite at a suitable temperature so that the chemical change is completely made. By aging the opacifier-silica gel-based composite, the network structure inside the silica gel is strengthened. You can. In addition, during aging, the moisture inside the silica gel may be replaced with a polar organic solvent, and as a result, it is possible to prevent the pore structure deformation and reduction of the silica gel due to evaporation of the moisture inside the silica gel in a subsequent drying process.

Specifically, the aging process may be carried out by maintaining the opacifying agent-silica gel-based composite at a temperature of 25 ° C. to 80 ° C., more specifically 50 to 80 ° C. in water, a polar organic solvent or a mixed solvent thereof. . In this case, the type of the polar organic solvent is the same as described above. However, the water, the polar organic solvent or a mixed solvent thereof may be used in an amount corresponding to a volume of 1 to 3 times the volume of the opacifying agent-silica gel-based composite.

In this case, a base may be further added to promote the reaction. The base may be the same as described above, and may be added in admixture with a polar organic solvent. Specifically, the base may be added in an amount of 20 parts by weight or less, more specifically 1 to 15 parts by weight, based on 100 parts by weight of the solvent added during the aging process.

In addition, the aging process may be performed until the chemical change in the opacifier-silica gel-based complex is completed, specifically, may be performed for 1 hour to 6 hours, or 1 hour to 2 hours.

On the other hand, the hydrophobized surface modification is a silane-based compound (for example, dimethyl dimethoxy silane, dimethyl diethoxy silane, methyl trimethoxy silane, vinyl trimethoxy silane, phenyl trimethoxy silane, tetraethoxy silane , Dimethyl dichloro silane, or 3-aminopropyl triethoxy silane, etc.), siloxane-based compounds (e.g., polydimethyl siloxane, polydiethyl siloxane, or octamethyl cyclotetra siloxane, etc.), silanol ) -Based compounds (e.g., trimethylsilanol, triethylsilanol, triphenylsilanol and t-butyldimethylsilanol, etc.) or silazane-based compounds (e.g. 1,2-diethyl Disilazane (1,2-diethyldisilazane), 1,1,2,2-tetramethyldisilazane (1,1,2,2-tetramethyldisilazane), 1,1,3,3- tetramethyldisilazane 1,1,3,3-tetramethyl disilazane), 1,1,1,2,2,2-hexamethyldisilazane (1,1,1,2,2,2-hexamethyldisilazane, HMDS), 1,1 , 2,2-tetra By using one or a mixture of two or more surface modifiers such as ethyldisilazane (1,1,2,2-tetraethyldisilazane) or 1,2-diisopropyldisilazane, etc. Can be.

In particular, the surface modifier may be a silazane-based compound including two or more alkyl groups in one molecule, and more specifically, the compound of Formula 1 below:

[Formula 1]

In Formula 1, R ¹¹ to R ¹³ , and R ²¹ to R ²³ may each independently be a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, provided that R ¹¹ to R ¹³ , and R ²¹ to R ²³ are each hydrogen at the same time. It is not an atom.

The silazane-based surface modifier may decompose when used with an alcohol-based compound to produce a 2-molecular alkoxysilane-based compound. In addition, the resulting alkoxysilane-based compound may contain up to three alkyl groups in one molecule, thereby further increasing the degree of hydrophobicity during surface modification of the silica aerogel. Accordingly, it is possible to minimize the amount of surface modifier used for hydrophobization of silica airgel.

Specific examples of the silazane-based compound include diethyldisilazane, tetramethyldisilazane, hexamethyldisilazane, tetraethyldisilazane or diisopropyldisilazane, and any one or two of them. Mixtures of the above may be used.

Among these, the silazane-based surface modifier may further increase the hydrophobicity of the silica airgel. In the silazane-based compound of Formula 1, tetraalkyldisilazane including four alkyl groups having 1 to 4 carbon atoms together with two hydrogen atoms may be used. Or hexaalkyldisilazane including six alkyl groups having 1 to 4 carbon atoms, and more specifically, hexamethyldisilazane (HMDS) or tetramethyldisilazane.

The surface modifier may be used in an amount of 0.6 parts by weight to 2 parts by weight based on 1 part by weight of silica contained in the sol. If the content of the surface modifier is less than 0.6 parts by weight, the hydrophobicity in the final silica airgel is low, there is a fear that the tap density may be increased, and when the content of the surface modifier exceeds 2 parts by weight, the tap density characteristics and the hydrophobicity may be increased. The effect of improving the degree characteristic may be insignificant. In view of the remarkable improvement of the use of the surface modifier, the surface modifier may be used in an amount of 0.6 parts by weight to 1.8 parts by weight, or 0.6 parts by weight to 1.2 parts by weight based on 1 part by weight of silica.

Specifically, the drying process may be performed by a supercritical drying process or an atmospheric pressure drying process using supercritical carbon dioxide.

Carbon dioxide (CO ₂ ) is a gaseous state at room temperature and atmospheric pressure, but if it exceeds a certain temperature and high pressure limit called the supercritical point, the evaporation process does not occur, so it becomes a critical state in which gas and liquid cannot be distinguished. Carbon dioxide in the state is called supercritical carbon dioxide. Supercritical carbon dioxide has a molecular density close to a liquid, but has a low viscosity, close to a gas, high diffusion efficiency, high drying efficiency, and short drying time.

The supercritical drying process may be performed according to a conventional method except for using the silica gel-based composite prepared in Step 2. Specifically, in the supercritical drying process, a silica gel-based composite is placed in a supercritical drying reactor, and then a solvent replacement process is performed in which a liquid CO ₂ is filled and the alcohol solvent inside the silica aerogel is replaced with CO ₂ . Thereafter, after raising the temperature to 40 ° C. to 50 ° C. at a constant temperature increase rate, specifically 0.1 ° C./min to 1 ° C./min, the pressure or more at which carbon dioxide becomes a supercritical state, specifically, 100 bar to 150 bar The pressure is maintained in a supercritical state of carbon dioxide for a period of time, specifically 20 minutes to 1 hour. In general, carbon dioxide is supercritical at a temperature of 31 ° C. and a pressure of 73.8 bar. The carbon dioxide may be maintained at a constant temperature and a constant pressure for 2 hours to 12 hours, more specifically, 2 hours to 6 hours at which the carbon dioxide becomes a supercritical state, and then the pressure may be gradually removed to complete the supercritical drying process.

In addition, in the case of the atmospheric pressure drying process, it can be carried out according to a conventional method such as natural drying under normal pressure (1 ± 0.3 atm), optionally heat treatment within 1 hour at 120 ℃ to 180 ℃ under the above pressure conditions May be In this case, in order to prevent aerogel structure shrinkage due to rapid drying of the residual solvent in the manufactured blanket, the blanket may be wrapped with a metal foil such as aluminum foil and then drilled through a plurality of holes.

As a result of the drying process as described above, a blanket comprising a porous silica airgel having nano-sized pores can be prepared.

As described above, the silica airgel-containing blanket prepared according to the above-described method may exhibit an improved flame retardancy along with low thermal conductivity since the opaque agent of the inorganic particles having excellent IR absorption ability is uniformly dispersed in the blanket. Accordingly, it is useful not only for thermal insulation thermal insulation plant facilities such as piping for various industrial facilities and industrial furnaces, but also as insulation, insulation, or non-combustible materials for aircraft, ships, automobiles, and building structures.

In addition, according to another embodiment of the present invention provides a dispersion containing an opaque agent, which is useful for the production of the blanket containing silica airgel.

As described above, the dispersion containing the opacifier is prepared by dispersing the inorganic particles in a basic aqueous solution containing a strong base and then etching them with water. The opacifier and water having the above-described physical properties as a result of chemical etching are prepared. It may include. At this time, the type and content of the opaque agent, and the method for producing a dispersion containing the opaque agent is as described above.

Hereinafter, the present invention will be described in more detail with reference to the following Examples and Experimental Examples. However, the following Examples and Experimental Examples are for illustrating the present invention and the scope of the present invention is not limited by these Examples and Experimental Examples.

Example 1

5 g of TiO ₂ having rutile crystallinity was added to a 2M potassium hydroxide (KOH) solution, and stirred for 3 hours to perform an etching reaction on TiO ₂ . 240 ml of water was added to the resulting etchant to purify to prepare a dispersion including an opaque agent in which TiO ₂ etched in water was dispersed.

To the precursor solution prepared by mixing 20 g of silica alkoxide precursor and 40 g of ethanol, 5 ml of the above-mentioned dispersion containing an opaque agent was added to prepare a composition for forming an opaque agent-silica aerogel.

A solution of 0.5 ml of an ammonia catalyst diluted with 12 ml of ethanol was added to the composition for forming a silica aerogel including the opaque agent so that the pH of the composition was 8-9, and cast on polyethylene terephthalate (PET) fiber to induce gelation. . After gelation was completed, the resulting opacifier-silica gel-based composite was aged at 50 ° C. for 70 minutes using 2.0% by weight aqueous ammonia solution. After completion of aging, the resulting opacifier-silica gel-based composite was subjected to hydrophobization surface modification for 12 hours using 80 ml of a surface modifier-containing solution prepared by mixing 4 ml of hexamethyldisilazane (HMDS) and 76 ml of ethanol. . After completion of the hydrophobization surface modification reaction, the resultant wet gel was dried at atmospheric pressure (1 atm) to prepare a blanket containing a silica airgel and an opaque agent of etched TiO ₂ .

Example 2

In Example 1, the blanket was subjected to the same method as in Example 1, except that PET fiber hydrophobized with hexamethyldisilazane (HMDS) was used instead of polyethylene terephthalate (PET) fiber. Prepared.

Comparative Example 1

To the precursor solution prepared by mixing 20 g of silica alkoxide precursor and 40 g of ethanol, 5 ml of a dispersion prepared by dispersing 5 g of TiO ₂ having rutile crystallinity as an opaque agent in 240 ml of distilled water was added to form an opaque agent-silica aerogel. The composition was prepared. To the composition containing the opaque agent-silica aerogel, a solution of 0.5 ml of an ammonia catalyst diluted with 12 ml of ethanol was added so that the pH of the composition was 8-9, and cast on PET fiber to induce gelation. After gelation was completed, the resulting opacifier-silica gel-based composite was aged at 50 ° C. for 70 minutes using 2.0% by weight aqueous ammonia solution. After completion of aging, the resulting opacifier-silica gel-based composite was subjected to hydrophobization surface modification for 12 hours using 80 ml of a surface modifier-containing solution prepared by mixing 4 ml of hexamethyldisilazane (HMDS) and 76 ml of ethanol. . After completion of the hydrophobization surface modification reaction, the resultant wet gel was dried at atmospheric pressure (1 atm) to prepare a blanket including silica airgel and an opacifying agent.

Experimental Example 1

The opaque agent prepared in Example 1 and Comparative Example 1 was observed using a transmission electron microscope. The results are shown in FIGS. 1 and 2, respectively.

As a result, in the case of the opaque agent prepared in Example 1, the inorganic particles in the average of four primary particles are bound in the unit volume, while in the case of the opaque agent of Comparative Example 1 which does not perform an etching process, It can be confirmed that the inorganic particles of 20 to 30 and an average of 25 primary particles are bonded and highly structured.

In addition, the opaque agent prepared in Example 1 had an average particle diameter (D ₅₀ ) of 320 nm, and the average particle diameter (D ₅₀ ) of the primary particulate inorganic particles constituting the same was 100 nm, and the surface of the primary particulate inorganic particles It was confirmed that fine irregularities were formed in the.

In addition, the blankets prepared in Examples 1 and 2 were milled under a condition of 6000 rpm using a milling equipment, and then observed using a transmission electron microscope. The results are shown in FIGS. 3 and 4.

In FIG. 3, a) is a TEM photograph of a composite of an airgel and an opaque agent in a blanket, b) is silicon (Si), and c) is titanium (Ti) in the composite. In FIG. 4, a) is a TEM photograph of the airgel and the opaque agent in the blanket, and b) is a photograph of the distribution of silicon (Si) in the blanket.

As a result, in the case of Example 1, a large amount of condensation-reactive functional groups, particularly hydroxy groups, are formed on the surface of the opaque agent by the etching process, and the opacity agent is well incorporated into the aerogel due to the enhancement of the bonding force with the silica precursor by the increased condensation-reactive functional group. You can see that. In addition, the airgel contained in the blanket was connected to each other to form a three-dimensional network structure.

On the other hand, in the blanket of Comparative Example 1 including an opaque agent that did not perform an etching process, the particle size of the opaque agent was large and the functionalities of the surface were small, so that it was easily separated from the airgel during the milling process. As a result, almost no Ti was observed upon TEM observation.

Experimental Example 2

The change of the average particle diameter and the average zeta potential was observed according to the amount of the base material used during the etching of the opacifying agent.

Specifically, in a potassium hydroxide solution prepared by varying the concentration of KOH as 0.1M, 1M, 2M, 4M and 10M as a base material, ₂ g of TiO ₂ having rutile crystallinity were added to each other at 25 ° C. for 2 hours. While stirring, the etching reaction was performed on TiO ₂ . 240 ml of water was added to the resulting etchant to purify to prepare a dispersion including an opaque agent in which TiO ₂ etched in water was dispersed. The zeta potential measuring device (Zetasizer Nano ZS90, manufactured by Malvern instruments) was used to measure the average particle diameter (avg.size) and average zeta potential (avg. Zeta potential) of TiO ₂ dispersed in the dispersion obtained above. The results are shown in FIG.

As a result, the absolute value of zeta potential of the opaque agent increases and the particle size decreases as the concentration of KOH increases. In addition, considering that the etching of inorganic particles is affected by the etching time along with the concentration of the base material, the zeta potential and particle size of the opacifier can be controlled by controlling the concentration of the base material and the etching time in the etchant. can do.

In addition, the particle size distribution of the opaque agent according to the etching or not was compared and evaluated.

In detail, except that 4M KOH is used as the base material, the etching process was performed once to three times in the same manner as above, and the particle size distribution of the opaque agent obtained according to the number of etching was observed. Particle size distribution was also observed for the opaque agent of Comparative Example 1, which was not subjected to the etching process for comparison. The results are shown in FIG.

As a result of the experiment, the opaque agent etched regardless of the number of etching showed a narrow particle distribution, it was confirmed that it has a uniform particle size.

On the other hand, in the case of the opaque agent of Comparative Example 1 was not dispersed in the dispersion medium when dispersed in the solvent for the particle size distribution analysis, it was impossible to measure. From these results, it can be seen that the opaque agent of Comparative Example 1 has a broad particle size distribution and no reproducibility.

In addition, the zeta potential of the opacifying agent in water was measured by the same method as described above with respect to the opacifying agent used or etched in Example 1 and Comparative Example 1. The results are shown in Table 1.

	Example 1	Comparative Example 1
Zeta potential (mV)	-31.3	-5.2

As a result, the absolute value of the zeta potential of the opacifying agent of Example 1 subjected to the etching process was significantly increased compared to that of the comparative example 1 which did not perform the etching process. From this, it can be seen that the content of functional groups on the surface of the opaque agent of Example 1 is increased by etching, and as a result, it can be expected that the dispersibility can be better.

Experimental Example 3

The dispersibility of the opaque agent prepared in Example 1 and Comparative Example 1 was evaluated.

After the dispersion prepared in Example 1 and Comparative Example 1, comprising the etched TiO ₂ a) immediately after the preparation, b) left to stand for 1 hour after preparation, and c) left to stand for 3 hours after preparation, the dispersion The transparency change of was observed, respectively. The results are shown in FIG.

As a result of the experiment, the dispersion containing the opaque agent prepared in Example 1 exhibited higher transparency compared to the dispersion of Comparative Example 1 immediately after preparation due to the uniform dispersion of the etched opaque agent. In addition, the dispersion containing the opaque agent prepared in Example 1 showed little change in transparency compared to Comparative Example 1 after 3 hours due to the excellent dispersion stability. On the other hand, in Comparative Example 1, the opacity of the dispersion was greatly reduced after 3 hours after the preparation of the dispersion due to precipitation of the opacifier.

Experimental Example 4

The average weight loss, thermal conductivity (T / C) and true density of the blankets prepared in Example 1 and Comparative Example 1 were measured, respectively. The results are shown in Table 2 below.

Average weight loss (ave.weight loss): After the hand-washing three times the same strength for the blanket of Example 1 and Comparative Example 1 prepared, the change in the weight of the blanket before the experiment was measured.

Thermal conductivity (T / C): The thermal conductivity of the blanket of Example 1 and Comparative Example 1 was measured on the conditions of normal temperature (25 degreeC) using the thermal conductivity measuring instrument (HFM436, NETZSCH company make).

True density: The weight ratio with respect to the unit volume of the blanket of Example 1 and the comparative example 1 which were manufactured was measured.

	Comparative Example 1	Example 1
Average weight loss (g)	0.15 g (white lump)	0.09 g (fine powder)
T / C (mW / mK)	15.1	13.4
True density (g / cc)	1.91	2.07

Considering that the true density of the silica airgel itself is 1.89 g / cc and the true density of the rutile TiO ₂ is 4.23 g / cc, the blanket according to Example 1 exhibited a higher true density than that of Comparative Example 1. From this, it can be seen that due to the etching effect of TiO ₂ , the blanket was more efficiently included in the blanket even when the same amount was used.

In addition, as the content of the opacifier increased, the blanket of Example 1 showed a thermal conductivity lower than 10% compared to that of Comparative Example 1.

In addition, the blanket of Example 1 exhibited a lower average weight loss compared to Comparative Example 1. Due therefrom by etching effect of TiO ₂ in the manufacture of blankets TiO ₂ is more excellent adhesion can be seen that attached to the blanket substrate.

Experimental Example 5

The specific surface area of the silica airgel in the blanket prepared in Example 1 and Comparative Example 1, the total pore volume and the average pore diameter (avg. Pore diameter) in the silica airgel was 3Flex (manufactured by Micromeritics). Each was measured using. The results are shown in Table 3 below.

	Comparative Example 1	Example 1	Reference Example
Specific surface area (m 2 / g)	789.9	850.8	761.4
Pore volume (cm 3 / g)	3.41	3.70	3.20
Pore diameter (nm)	12.23	12.07	12.55

Reference Example in Table 3 is a value for the silica airgel in the blanket prepared by carrying out the same method except in the manufacture of the blanket according to Comparative Example 1 using no opaque agent in the same manner.

As a result of the experiment, the surface area of the blanket prepared silica airgel containing the increase in the surface area of the TiO ₂ by the etching was increased, it can be seen that the finer pores are formed with a higher porosity than in Comparative Example 1.

Experimental Example 6

The hydrophobic change of the blanket prepared in Example 1 and Comparative Example 1 including the silica airgel was observed according to the high temperature treatment.

In detail, the blanket containing the silica airgel prepared in Example 1 and Comparative Example 1 and the blanket was heat-treated at 300 ° C. and 400 ° C. for 10 hours, and then the carbon (C) amount was changed using a carbon analyzer. The carbon content was measured. Each experiment was repeated twice. The results are shown in Table 4 below.

	C content
	Room temperature (23 ℃)		After 300 ℃ / 10 hours treatment		After 400 ℃ / 10 hours treatment
	Example 1	Comparative Example 1	Example 1	Comparative Example 1	Example 1	Comparative Example 1
Primary	8.99	9.51	3.13	2.70	1.57	1.05
Secondary	8.95	10.11	2.99	2.59	1.45	1.02
Average	9.0	9.8	3.1	2.6	1.5	1.0

As a result of the experiment, due to the increase in the surface area of the etched TiO ₂ , the blanket of Example 1 had a smaller hydrophobic decrease compared to Comparative Example 1 even after the high temperature treatment.

Claims (18)

1. Blanket substrate; And

   At least one of the surface and the inside of the blanket substrate, comprising a silica airgel and an opacifier,

   The opacifying agent is a silica airgel-containing blanket is a secondary particle shape in which the inorganic particles on the primary particles are aggregated, and contains 1 to 5 inorganic particles per 1 μm ³ unit volume.
2. The method of claim 1,

   The opaque agent is a blanket of silica airgel containing an average particle diameter of 300nm to 1600nm.
3. The method of claim 1,

   The inorganic particle blanket blanket silica silica gel containing any one or two or more condensation functional groups selected from the group consisting of hydroxy group, alkoxy group, carboxyl group and ester group on the surface of the particle.
4. The method of claim 1,

   The inorganic particle is a blanket blanket silica silica gel having irregularities on the surface.
5. The method of claim 1,

   The inorganic particle comprises a blanket, silica airgel containing any one or two selected from the group consisting of metal oxides, metal carbides, metal nitrides, metal hydroxides, metal salts, carbon-based materials, ceramic particles and mixtures thereof.
6. The method of claim 1,

   The inorganic particle is a blanket containing silica airgel that comprises at least one titanium oxide selected from the group consisting of rutile TiO ₂ and anatase type TiO ₂ .
7. The method of claim 1,

   The silica airgel blanket having a silica airgel that has a three-dimensional network structure combined primary particles.
8. The method of claim 1,

   The silica airgel is a blanket of silica airgel containing a specific surface area of 700m ² / g or more.
9. The method of claim 1,

   The silica airgel blanket is a silica airgel containing silica airgel is a hydrophobic silica airgel having a carbon content of at least 8% by weight relative to the total weight of the silica airgel.
10. The method of claim 1,

    The blanket substrate is a silica airgel blanket comprising a hydrophobic surface treatment layer on at least one side of the substrate.
11. The method of claim 1,

    The opaque agent comprises a silica airgel blanket that is chemically bonded to the silica airgel to form an opaque-silica airgel complex.
12. Dispersing the inorganic particles in the basic aqueous solution to be etched and preparing water, followed by adding water to prepare a dispersion containing an opacifier;

    Mixing the opacifier-containing dispersion with a silica precursor to prepare a composition for opacifier-containing silica airgel formation;

    Preparing an opaque agent-silica gel-based composite by adding a base catalyst and a polar organic solvent to the composition for forming an air opaque agent-silica aerogel, and adding and gelling the substrate for the blanket; And

    Hydrophobizing surface-modifying the opacifier-silica gel-based composite and then drying

    Method for producing a blanket containing silica airgel comprising a.
13. The method of claim 12,

    The basic aqueous solution is a silica airgel-containing blanket manufacturing method comprising a strong base and water having an acid dissociation constant value of 12 or more.
14. The method of claim 12,

    The etching may be performed by dispersing the inorganic particles in a basic aqueous solution containing a strong base having a dissociation constant value of 12 or more at a concentration of 0.1M to 10M, and then the average amount of the opaque agent in the final opaque-dispersing agent-containing dispersion is -10 mV to -60 mV. A method for preparing a blanket containing silica airgel that is carried out for a time to exhibit a zeta potential.
15. The method of claim 12,

    The hydrophobization surface modification is a method for producing a blanket containing silica airgel that is carried out using a silazane-based surface modifier comprising two or more alkyl groups in the molecule.
16. A heat insulating material comprising a blanket comprising a silica airgel according to any one of claims 1 to 11.
17. Contains an opaque agent and water,

    The opacifying agent is a dispersion comprising an opacifying agent is the average zeta potential in water is -10mV to -60mV.
18. The method of claim 17,

    The opacifying agent is a dispersion in which the inorganic particles on the primary particles are agglomerated secondary particles, containing 1 to 5 inorganic particles per 1 μm ³ unit volume.

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