DESC:Field of the invention

[0001] The present invention relates to an insulated mat or sheet. More specifically, the present invention relates to a lightweight fibrous mat with embedded LCHP.

Background of the invention:

[0002] Presently, the demand for efficient thermal insulation materials has been steadily increasing across various industries, ranging from construction to transportation. Conventional and traditional insulation materials, often face challenges related to weight, flexibility, mechanical stability and efficiency. Existing insulation materials are bulky and rigid which fail to adapt in applications of irregular surfaces. Innovations in materials science have driven the development of lightweight, flexible, and high-performance insulation solutions.

[0003] One significant challenge in the field of thermal insulation is the need for materials that offer low thermal conductivity, mechanical strength and stability and adaptability to diverse shapes and surfaces. Conventional materials may lack the desired combination of properties, especially when faced with curved or irregular structures that require flexible or rigid panels.

[0004] Traditional insulation materials, such as rigid foam panels or dense fibers, tend to be heavy and lack flexibility. This poses challenges in applications where weight is a critical factor, such as in aerospace or automotive industries. Moreover, these materials may struggle to conform to irregular or curved surfaces, limiting their effectiveness in certain environments and applications.

[0005] Ensuring both mechanical stability and thermal insulation performance of the insulation material can be challenging. Conventional insulation materials may compromise one aspect for the other, leading to difficulties in meeting the diverse requirements of modern applications. For instance, mechanically robust insulation materials might lack the necessary flexibility for use in dynamic or irregular shapes and structures.

[0006] Many industries require insulation materials that can adapt to a wide range of shapes and structures, including curved or irregular surfaces. Existing solutions often fall short in providing materials that can be easily molded or applied to intricate designs without compromising their insulation properties.

[0007] Maintaining low thermal conductivity is crucial for effective insulation. Traditional insulation materials may struggle to achieve the desired balance between low thermal conductivity and other essential properties. This challenge becomes particularly pronounced in applications where minimizing heat transfer is critical, such as in the construction of energy-efficient buildings or the development of high-performance electronic devices.

[0008] Therefore, there is a need there is a need for a lightweight fibrous mat with embedded LCHP acting as a thermal insulation which can overcome few or all drawbacks of the existing prior art.

Objects of the invention:

[0009] An object of the present invention is to provide a lightweight fibrous mat with embedded LCHP which has low thermal conductivity.

[0010] One more object of the present invention is to provide a lightweight fibrous mat with embedded LCHP which is mechanically stable.

[0011] Another object of the present invention is to provide a lightweight fibrous mat with embedded LCHP which is used to produce panels.

[0012] Yet another object of the present invention is to provide a lightweight fibrous mat with embedded LCHP which conform to irregular and curved surfaces, making it ideal for use in complex or non-standard structures.
[0013] Further an object of the present invention is to provide a method for preparing a lightweight fibrous mat with embedded LCHP.

[0014] Another object of the present invention is to provide a method for preparing low conductivity hydrophobic powder particles.

Summary of the Invention

[0015] The disclosed invention is a lightweight fibrous mat for thermal insulation which comprises a fiber layer made of fibers which are interconnected and bonded to each other to form a robust network and a low conductivity hydrophobic powder (LCHP) particles embedded within the fiber layer. The lightweight fibrous mat exhibits a low thermal conductivity.

[0016] The invention also mainly discloses a method for preparing a lightweight fibrous mat with embedded LCHP which comprises steps of formulating a first sol by combining predefined amount of methyl trimethoxy silane with of ethanol in the presence of an acid catalyst such as oxalic acid , added in batches during the initial stages of the process, preparing a second sol by introducing second predefined amount of methyl trimethoxy silane into ethanol, followed by heating the second sol at 50-70°C for at least an hour, with continuous stirring and then cooling to room temperature and mixing of second sol uniformly after cooling to room temperature by placing in the container of an ultrasonic testing machine , and inserting a probe into the container, and generating shock waves on starting of electricity supply and cooling the container continuously by maintain a cool water bath around it, later on adding a base catalyst to the second sol while mixing.

[0017] A combined sol is prepared by combining the first sol with the second sol at a slow rate and hydrolysing for 24 hours and later impregnating the combined sol with fiber layer under vacuum conditions at a pressure of 10 mm of Hg wherein the combined sol penetrates the fiber layer and LCHP precursors are embedded within the fiber layer.

[0018] The next step involves gelating the impregnated fiber layer in a vessel, wherein the temperature of the vessel is varied between -15°C and 30°C for a period of 2 to 3 hours twice each thereby forming LCHP particles in situ within the fiber layer and later aging the gelled fiber layer in an ethanol environment for 24 to 72 hours. The resultant mat is obtained after draining the ethanol and combined sol from the vessel at a constant rate. The resulting mat is dried for 1-2 hours, with the flow of supercritical carbon dioxide and then thermally consolidating the resulting mat at 100 to 150°C for at least an hour to 2 hours to achieve a lightweight fibrous mat with embedded LCHP particles.

Brief description of drawings:
[0019] The advantages and features of the present invention will be understood better with reference to the following detailed description and claims taken in conjunction with the accompanying drawings, wherein like elements are identified with like symbols, and in which:

[0020] Figure 1 shows a flow chart of a preparation method for a lightweight fibrous mat with embedded LCHP in accordance with the present invention.
[0021] Figure 2 shows a flow chart of a preparation method for low conductivity hydrophobic powder (LCHP) particles in accordance with the present invention.

Detailed description of the invention

[0022] An embodiment of this invention, illustrating its features, will now be described in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open-ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items.

[0023] The terms “first,” “second,” and the like, herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another, and the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

[0024] The disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms.

[0025] The present invention relates to a lightweight fibrous mat and method of preparing same for thermal insulation, acoustic absorption, and adsorption of liquids, vapours, and gases. The present invention pertains to a novel lightweight fibrous mat designed for thermal insulation and other applications.

[0026] The lightweight fibrous mat comprises a fiber layer and low conductivity hydrophobic powder particles. The mat comprises at least one layer of fiber and one layer of low-conductivity hydrophobic powder (LCHP) particles, which are embedded within the fiber layer. The lightweight fibrous mat exhibits low thermal conductivity.

[0027] The fiber layer in the mat serves as the foundational element for the entire structure. The fiber layer includes at least one layer of fiber nonwoven, this layer is meticulously designed for optimal performance. The fiber layer are interconnected and bonded to each other to form a robust network.

[0028] The fibers used in the fiber layer include a variety of organic materials such as polyester and glass fiber which are preferably used. While the fiber layer is also made of organic materials like polyamide, meta-aramid, para-aramid, polyolefin, wool, viscose, acrylic and rayon.

[0029] In an embodiment, polystyrene (EPS) or polyurethane foam may be used in place of fiber layer. In another embodiment, mineral wool may be used in place of fiber layer. In another embodiment, Natural fibers such as cotton, hemp, or wool may be used in place of the fiber layer. The person skilled in the art can arrange any alternative to fiber to get the desired result.

[0030] The fibers are intricately bonded to not only embed low conductivity hydrophobic powder (LCHP) particles, but also to each other, to form a resilient network that ensures structural integrity even in irregular and dynamic conditions. This interconnectivity is complemented by the intentional selection of diverse organic fibers, facilitating adaptability and flexibility. Fiber nonwoven structure is critical for the final performance of the mat, as it provides the mechanical support for the embedded LCHP particles.

[0031] The selection of fibers with different cross-sectional shapes and diameters smaller than low conductivity hydrophobic powder (LCHP) particles ensures effective binding and contributes to the flexibility and strength of the overall mat structure. The ability of fiber to conform to various shapes, including curved or irregular surfaces, round, trilobal, pentalobal, ribbony, dumb bell shaped or star shaped in cross-section underscores its versatility.

[0032] The diameters of the fibers are chosen to be smaller than of LCHP particles to ensure effective binding, preventing shedding or detachment of granules under mechanical stress. Very thin fibers can be used to produce mat which are flexible and thicker fibers having greater bending stiffness are needed to bulkier and more rigid mat.

[0033] The linear density of the fibers typically ranges from 1.2 dtex to 2.4 dtex, though adjustments can be made depending on the desired flexibility or rigidity of the lightweight fibrous mat. The range allows for the production of the mat that is both flexible enough to conform to irregular or curved surfaces, yet strong enough to withstand mechanical stress and environmental conditions.

[0034] The fiber layer is primarily designed for thermal insulation, the fiber layer has utility in various industries where effective heat regulation is crucial, the fiber material has industrial-grade fibers. The fiber layer's flexibility allows it to conform to irregular surfaces, making it suitable for insulation in curved or irregular structures. Additionally, the fiber layer serves as an effective acoustic absorption material due to its low sound velocity. The fiber layer porosity makes it applicable as an adsorption material for liquids, vapors, and gases, with specific relevance to scenarios like oil spills during transportation.

[0035] The Low Conductivity hydrophobic powder (LCHP) possess porosities about 60%-90% and density below 0.092 to 0.22 g/cm3. The low density enables the lightweight of the fibrous mat. Also, the porosity of the particles improves the thermal insulation capabilities, preventing heat transfer. The LCHP has low conductivity which make it ideal for applications in thermal insulation.

[0036] The LCHP can be produced in various forms, including gels with enclosed air, through gelation under vacuum or microgravity conditions or by drying a suitable gel. The shaping of LCHP is achieved during the sol-gel process, and the external shape can be modified through comminution after gel drying, involving grinding and milling processes to produce particulate nanoparticles.

[0037] The LCHP particles are based on metal oxides of silicon or aluminum, though other organic materials based on silicon with similar properties can be used. The silicon dioxide compounds is preferable as when considered for sol gel technique. In another embodiment oxides of titanium, zinc, iron, manganese, and zirconium can also be used instead of oxides of silicon or aluminum.

[0038] The LCHP particles have hydrophobic surface groups that helps in preventing moisture collapse of the structure ensuring stability and durability. The fire class of the mat is determined by the fire class of LCHP particles and fibers, necessitating the use of low flammability fibers.

[0039] The applications of LCHP include insulation for curved or irregular surfaces, necessitating flexible or rigid panels composed of the insulant.

[0040] Referring now to figure 1, a method (1000) for making a lightweight fibrous mat with embedded LCHP particles in accordance with the present invention is illustrated. The method (1000) is described in conjunction with the lightweight fibrous mat with embedded LCHP described in the above paragraphs.

[0041] The method (1000) starts at step (1100).

[0042] At step (1200), in the initial stage, a first sol is prepared by combining first predefined amount of methyl trimethoxy silane with ethanol. An acid catalyst, specifically oxalic acid is added in batches during the process. It may be obvious to a person skilled in the art to use tetra ethyl orthosilicate, tetra methyl orthosilicate, sodium silicates, polysiloxanes and so on in place of methyl trimethoxy silane.

[0043] In present embodiment, the first sol is prepared by combination of 65 ml of methyl trimethoxy silane with 630 ml of ethanol. The synthesis occurs in the presence of an acid catalyst, specifically 100 ml of oxalic acid.

[0044] Further at step (1300), a second sol is prepared by introducing second predefined amount of methyl trimethoxy silane into of ethanol, after 12 hours. The second sol then undergoes controlled heating at 50 – 70°C for a duration of at least an hour, with continuous stirring to ensure uniformity. After heating, the sol is carefully allowed to cool down to room temperature.

[0045] It may be obvious to a person skilled in the art to use any alcohols like methanol, propanol, butanol, acetone, hexane and the like in place of ethanol for preparation of first sol and second sol.

[0046] In present embodiment, the second sol is prepared by introducing 385 ml of methyl trimethoxy silane into 700 ml of ethanol, after 12 hours the sol undergoes a controlled heating process at 60°C for a duration of 1 hour, with continuous stirring.

[0047] At Step (1400), the second sol is uniformly mixed by placing in the container of ultrasonic testing machine and inserting probes in the container. A machine generates shock wave of more than 20 kHz on starting of the electrical supply which results in mixing of the second sol. The container is continuously cooled down by maintaining a cooled water bath around it.
[0048] Further the method involve step (1500), after the cooling of the second sol, a 100 ml of base catalyst is added to the second sol along with stirring. In the present embodiment, the base catalyst used is ammonium hydroxide. It may be obvious to a person skilled in the art to use sodium hydroxide, sodium carbonate, or potassium carbonate and the like as the base catalyst.

[0049] At Step (1600), the first sol is slowly added to the second sol. The combination of the sol is subjected to hydrolysis. This results in a combined sol. The hydrolysis is done for 24 hours which ensures the sol particles undergo chemical reactions forming a stable solution at end.

[0050] Further at step (1700), the combined sol then impregnated into a fiber layer which is done under vacuum conditions, wherein the combined sol penetrates the fiber layer and LCHP precursors are embedded within the fiber layer.

[0051] A pressure of 10 mm of Hg is used during impregnation process. The vacuum ensures evenly distribution of combined sol throughout the fiber, for incorporation of LCHP particles.

[0052] At Step (1800), the impregnated fiber layer undergoes gelation process. The gelation process takes place in a vessel equipped with a chiller apparatus and heating element. The temperature is alternated between -15°C and 30°C for a period of 2 to 3 hours twice each for formation of gel form. After a 4-hour gelation period, the temperature is lowered to -15°C and maintained for 3 hours, later the temperature is elevated to 30°C for another 3 hours. Later on, the temperature is again reduced to -15°C for a duration of 2 hours, and subsequently raised to 30°C and maintained at this level for 2 hours, thereby forming LCHP particles in situ within the fiber layer. This temperature cycles ensures the LCHP particles are integrated and evenly distributed into the fiber layer and solidify the combined sol within the fibers.

[0053] Further at step (1900), the gelled fiber layer undergoes aging process for over a period of 24 to 72 hours within an ethanol environment. The aging stabilizes the gelled fiber layer and promote bonding in LCHP particles. After aging process, the ethanol and the combined sol are drained out from vessel through perforated bottom at a constant rate, obtaining a resulting mat. In present embodiment the aging process is carried out for 36 hours.

[0054] Further the method involve step (2000), where the resulting mat undergoes supercritical drying process for a duration of 1-2 hours to remove any residual or additional solvent. Supercritical carbon dioxide is used inside the extractor for drying and the direction of flow was kept from bottom to top ensuring uniform drying throughout the mat. This step removes any remaining moisture and maintain the structure of the mat.

[0055] At Step (2100), later, the resulting mat is subjected to thermal consolidation at a temperature between 100 to 150°C for a time duration varying from at least 1 hour to 2 hours to obtain a lightweight fibrous mat with embedded LCHP particles. At this stage, the volume proportion of the LCHP particles in the consolidated mat is established at 60% ensuring thermal insulation properties. The step ensures that the mat achieves the desired thermal insulation properties and mechanical strength and stability. In present embodiment, the resulting mat undergoes thermal consolidation at temperature 150°C for period of 60 minutes.

[0056] The method (1000) ends at step (2200).

[0057] The lightweight fibrous mat is complete with weight of 1500 GSM (grams per square meter) and its thermal conductivity of the mat is 0.018 W/mK, as measured by Kawabata Thermolabo KESF-7. These characteristics make the mat an effective option as a thermal insulation while remaining flexible and durable to use in various industrial applications.

[0058] The lightweight fibrous mat has several advantages and properties including low thermal conductivity, mechanical stability, adsorption capability, acoustic absorption. The mat’s composition and featuring blend of fibers such as glass fiber and polyester with LCHP particles results in a mechanical stable and lightweight material. This combination gives a mat with low thermal conductivity making it an excellent thermal insulation material. The in-situ synthesis of LCHP particles within the fiber nonwoven ensures a high-volume proportion of LCHP, enhancing the mat's insulation capabilities.
[0059] The present invention of lightweight fibrous mat has exceptional application in thermal insulation. Due to the versatility of the mat, it finds its application in acoustic absorption due to low sound velocity. The mat can be used in soundproofing applications, where its low sound velocity helps dampen noise and reduce unwanted vibrations. The mat, also serves as an effective adsorption material for liquids, gases and vapours enabling it for a valuable solution for scenarios such as oil spills during transportation. The porous structure allows for the efficient capture and containment of various substances. The lightweight fibrous mat is also used in varied insulation applications as internal wall insulation and fire protection sheets.

[0060] The lightweight fibrous mat also tested for hydrophobicity enabling it to be used as insulation in high and low temperatures and hot and cold applications. The mat also maintains its hydrophobicity at elevated temperatures which makes it suitable for applications in oil and gas industries. The applications may include storage of LNG (liquefied natural gas), PNG (piped natural gas) and liquid nitrogen.

[0061] Referring now to figure 2, a method (3000) for making low conductivity hydrophobic powder (LCHP) particles in accordance with the present invention is illustrated.

[0062] The method (3000) starts at step (3100).
[0063] At step (3200), in the initial stage, a first sol is prepared by combining first predefined amount of methyl trimethoxy silane with ethanol. An acid catalyst, specifically oxalic acid is added in batches during the process. It may be obvious to a person skilled in the art to use tetra ethyl orthosilicate, tetra methyl orthosilicate, sodium silicates, polysiloxanes and so on in place of methyl trimethoxy silane.

[0064] In present embodiment, the first sol is prepared by combination of 65 ml of methyl trimethoxy silane with 630 ml of ethanol. The synthesis occurs in the presence of an acid catalyst, specifically 100 ml of oxalic acid.

[0065] Further at step (3300), a second sol is prepared by introducing second predefined amount of methyl trimethoxy silane into of ethanol, after 12 hours. The second sol then undergoes controlled heating at 50 – 70°C for a duration of at least an hour, with continuous stirring to ensure uniformity. After heating, the sol is carefully allowed to cool down to room temperature.

[0066] It may be obvious to a person skilled in the art to use any alcohols like methanol, propanol, butanol, acetone, hexane and the like in place of ethanol for preparation of first sol and second sol.

[0067] In present embodiment, the second sol is prepared by introducing 385 ml of methyl trimethoxy silane into 700 ml of ethanol, after 12 hours the sol undergoes a controlled heating process at 60°C for a duration of 1 hour, with continuous stirring.

[0068] At Step (3400), the second sol is uniformly mixed by placing in the container of ultrasonic testing machine and inserting probes in the container. A machine generates shock wave of more than 20 kHz on starting of the electrical supply which results in mixing of the second sol. The container is continuously cooled down by maintaining a cooled water bath around it.

[0069] Further the method involve step (3500), where after the cooling of the second sol, a 100 ml of base catalyst is added to the second sol along with stirring. In the present embodiment, the base catalyst used is ammonium hydroxide. It may be obvious to a person skilled in the art to use sodium hydroxide, sodium carbonate, or potassium carbonate and the like as the base catalyst.

[0070] At Step (3600), the first sol is slowly added to the second sol. The combination of the sol is subjected to hydrolysis. This results in a combined sol. The hydrolysis is done for 24 hours which ensures the sol particles undergo chemical reactions forming a stable solution at end.

[0071] The combined sol is kept in CO2 supercritical drying machine to obtain low conductivity hydrophobic powder (LCHP) particles. The combined sol is immersed in liquid carbon dioxide at 25° C and 120 bar pressure for 30 minutes. Later, the combined sol is heated at pressure between 50 to 120 bars for around 90 minutes at supercritical temperature. The heating and recirculation of the sol results in LCHP lumps. The LCHP lumps are grinded to get superfine LCHP particles.

[0072] The method (3000) ends at step (3700).

[0073] The LCHP particles produced in the method (3000) by supercritical CO2 drying has enhanced thermal insulation and hydrophobic properties. The LCHP particle has the pore size in the mesoporous range of 2-50 nm, leading to high surface area and low thermal conductivity.

[0074] The LCHP particles has characteristics such as thermal stability upto 400° C to 700° C and silica content greater than 90%. The methyl groups (–CH3) are functionalized to enhance the hydrophobicity of LCHP particles.

[0075] The LCHP particles produced exhibit properties such as density ranging between 0.01 g/cm³ and 0.5 g/cm³ and specific surface area of 600–1500 m²/g. The LCHP particles has porosity ranging between 80% to 99.8% and thermal conductivity in range from 0.01–0.03 W/mK. The LCHP particles has hydrophobicity with water contact angle exceeding 120°.

[0076] The LCHP particles can be used as thermal insulation in high performance applications. The LCHP particles can be employed for oil adsorption with an adsorption capacity exceeding 10 times its weight and can be integrated into coatings for moisture sensitive electronics.

[0077] The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to explain the principles of the present invention best and its practical application, to thereby enabling others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the claims of the present invention.
,CLAIMS:We Claim:

1. A method (1000) for preparing a lightweight fibrous mat with embedded LCHP, the method (1000) comprising the steps of:
formulating a first sol by combining a first predefined amount of methyl trimethoxy silane with ethanol in the presence of an acid catalyst, added in batches during the initial stages of the process;
preparing a second sol by introducing a second predefined amount of methyl trimethoxy silane into ethanol, followed by heating the second sol between the range of 50- 70°C for at least an hour, with continuous stirring and then cooling to room temperature;
mixing of second sol uniformly after cooling to room temperature by placing in a container of an ultrasonic testing machine, and inserting a probe into the container, and generating shock waves on starting of electricity supply and cooling the container continuously by maintaining a cool water bath around it;
adding a base catalyst to the second sol while mixing;
preparing a combined sol by combining the first sol with the second sol at a slow rate and hydrolysing for at least 24 hours;
impregnating the combined sol with a fiber layer under vacuum conditions at a pressure of 10 mm of Hg, wherein the combined sol penetrates the fiber layer and LCHP precursors are embedded within the fiber layer;
gelating the impregnated fiber layer in a vessel, wherein the temperature of the vessel is varied between -15°C and 30°C for a period of 2 to 3 hours twice each, thereby forming LCHP particles in situ within the fiber layer;
aging the gelled fiber layer in an ethanol environment for a period of 24 to 72 hours;
draining the ethanol and combined sol from the vessel at a constant rate, obtaining a resulting mat;
drying of the resulting mat for 1-2 hours, with the flow of supercritical carbon dioxide; and
thermally consolidating the dried resulting mat at temperature ranging from 100°C to 150°C for period of at least an hour to 2 hours, thereby forming a lightweight fibrous mat with embedded LCHP particles.

2. The method (1000) as claimed in claim 1, wherein the first sol is formulated by combining 65 ml of methyl trimethoxy silane with 630 ml of ethanol in the presence of 100 ml of an acid catalyst.

3. The method (1000) as claimed in claim 1, wherein the second sol is prepared by introducing 385 ml of methyl trimethoxy silane into 700 ml of ethanol.

4. The method (1000) as claimed in claim 1, wherein thermal conductivity of the lightweight fibrous mat is 0.018 W/mK.

5. The method (1000) as claimed in claim 1, wherein the weight of the lightweight fibrous mat is 1500 grams per square meter (GSM).

6. The method (1000) as claimed in claimed 1, wherein the base catalyst is ammonium hydroxide.

7. A method (3000) for preparing LCHP particle, the method comprising of the steps:
formulating a first sol by combining a first predefined amount of methyl trimethoxy silane with ethanol in the presence of an acid catalyst, added in batches during the initial stages of the process;
preparing a second sol by introducing a second predefined amount of methyl trimethoxy silane into ethanol, followed by heating the second sol between the range of 50- 70°C for at least an hour, with continuous stirring and then cooling to room temperature;
mixing of second sol uniformly after cooling to room temperature by placing in a container of an ultrasonic testing machine, and inserting a probe into the container, and generating shock waves on starting of electricity supply and cooling the container continuously by maintaining a cool water bath around it;
adding a base catalyst to the second sol while mixing;
preparing a combined sol by combining the first sol with the second sol at a slow rate and hydrolysing for at least 24 hours, wherein the combined sol is dried supercritically with CO2, then heated and grinded to obtain the LCHP particles.

8. A method (3000) as claimed in claim 7, wherein the first sol is formulated by combining 65 ml of methyl trimethoxy silane with 630 ml of ethanol in the presence of 100 ml of an acid catalyst and the second sol is prepared by introducing 385 ml of methyl trimethoxy silane into 700 ml of ethanol and the base catalyst is ammonium hydroxide.

9. The method (1000) as claimed in claim 1, wherein the resultant lightweight fibrous mat includes:
a fiber layer made of fibers which are interconnected and bonded to each other to form a robust network;
a low conductivity hydrophobic powder (LCHP) particles embedded within the fiber layer;
wherein the resultant lightweight fibrous mat exhibits a low thermal conductivity.

10. The lightweight fibrous mat as claimed in claim 9 , wherein the fiber layer comprises organic fibers selected from the group consisting of polyester, glass fiber, polyamide, meta-aramid, para-aramid, polyolefin, wool, viscose, acrylic, and rayon.

11. The lightweight fibrous mat as claimed in claim 9 , wherein the fibers are flexible and conform to various shapes, including curved or irregular surfaces, and have cross-sectional geometries selected from the group consisting of round, trilobal, pentalobal, ribbony, dumbbell-shaped, and star-shaped.

12. The lightweight fibrous mat as claimed in claim 9 , wherein the low conductivity hydrophobic powder particles are selected from the group of oxides of silicon and aluminium.

13. The light weight fibrous mat as claimed in claim 9, wherein the diameter of fbers is smaller than average diameter of LCHP particles to ensure effective binding of a high proportion of LCHP particles in the nonwoven fibers.