Insulating material

Abstract

An insulating material comprising a porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone and expanded glass beads, modified with silica aerogel, wherein the silica aerogel is embedded within pores of the porous material.

Description

[0001] INSULATING MATERIAL

[0002] The present invention relates to an insulating material comprising a porous material modified with silica aerogel.

[0003] Background art

[0004] As is known, in the construction industry, one of the main goals is to achieve high energy performance of buildings, improving living comfort, ensuring excellent thermal insulation, insulation from heat and cold, and reducing energy consumption for both winter heating and summer cooling.

[0005] This goal is equally sought in the case of renovations as well, in order to improve existing buildings from an energy standpoint.

[0006] One of the most effective tools for improving the energy performance of a building is thermal cladding, a system for thermal insulation of the exterior that makes it possible to optimize the thermal insulation between the interior and exterior of the building.

[0007] Moreover, thermal cladding contributes to increasing the degree of acoustic insulation of the home and solves the problem of thermal bridges, i.e., the points of the building exterior where heat is lost or condensation and mold form.

[0008] Furthermore, the provision of thermal cladding and the consequent energy efficiency improvement entail an improvement in the energy class of the building, thus ensuring a revaluation of the property itself.

[0009] Thermal cladding, whether provided on the outside or inside of the building, comprises several elements, such as adhesive, a layer of thermal insulation material, anchoring screws, a base coat, a reinforcement layer or reinforcement, a finish coat plaster, and any accessories.

[0010] The layer of thermal insulation material can be provided in various ways, for example by means of prefabricated panels or by means of a resin or other material applied on site.

[0011] One of the problems with solutions, whether prefabricated panels or substances applied on site, is their synthetic nature. This material is therefore often highly flammable, with obvious negative consequences on the safety of the building thus constructed.

[0012] Currently, building insulation uses rock wool, which is advantageously fireproof and has a low heat transmission rate. However, the disposal of said material presents problems and entails high costs. In fact, rock wool is considered special waste, harmful to human health, which requires incineration, with a considerable environmental impact in terms of CO2.

[0013] The aim of the present invention is to provide an insulating material that is fire-retardant and at the same time breathable and hydrophobic.

[0014] Within this aim, an object of the invention is to obtain an insulating panel that is flame-retardant.

[0015] A further object of the invention is to offer a material that allows high energy performance to be achieved by the building that is insulated by means of the same, for example in the form of panels.

[0016] Another object is to provide a material that makes it possible to obtain high acoustic insulation.

[0017] Another object of the invention is to provide an insulating material whose disposal is less problematic with respect to rock wool.

[0018] Not least object of the present invention is to provide a material and a method for its provision with low environmental impact.

[0019] This aim, as well as these and other objects that will become more apparent hereinafter, are achieved by an insulating material comprising a porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone and expanded glass beads, modified with silica aerogel, characterized in that it comprises silica aerogel embedded within pores of said porous material.

[0020] The above aim and objects of the present invention are also achieved by a method for providing the insulating material according to the invention, comprising the steps of: (i) forming a first mixture in a mixing chamber by adding under agitation at a speed comprised between 1500 rpm and 1900 rpm:

[0021] - water preheated to a temperature comprised between 30 °C and 75°C, preferably 60°C,

[0022] - silica aerogel, and

[0023] - a foaming agent;

[0024] (ii) closing hermetically the mixing chamber and heating the first mixture obtained in step (i) to a temperature comprised between 30°C and 75°C, preferably 60°C, mixing for a time comprised between 3 minutes and 7 minutes, preferably 5 minutes, at a speed comprised between 1500 rpm and 1900 rpm;

[0025] (iii) forming a second mixture by adding, while stirring at a rate comprised between 40 and 60 rpm, preferably 50 rpm, for a time comprised between 3 and 7 minutes, preferably 5 minutes, a porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone, and expanded glass beads;

[0026] (iv) cooling the second mixture obtained in step (iii) to a temperature lower than or equal to 30°C by adding liquid nitrogen.

[0027] The above aim and objects of the invention are also achieved by an article comprising the construction material according to the invention.

[0028] In a first aspect, the present invention therefore relates to an insulating material comprising a porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone, and expanded glass beads, modified with silica aerogel, characterized in that it comprises silica aerogel embedded within pores of said porous material.

[0029] Preferably, the porous material is in the form of granules.

[0030] In a preferred embodiment, the porous material is expanded pearlite. For example, it is possible to use pearlite of the peralit®13 type (Perlite Italiana SRL), characterized by a particle size of 0.1 mm, a density of 60 kg / m3, and X 0.041. Preferably, the aerogel is in a quantity comprised between 0.7% and 75%, preferably between 0.7% and 40% by weight on the total weight of said insulating material. The aerogel is preferably silica aerogel with a density of 50-70 kg / m3, for example aerogel produced by AerogelZone™, characterized by a density of 50 kg / m3and a thermal conductivity X of 0.018.

[0031] Preferably, the insulating material according to the invention is characterized by a density comprised between 120 kg / m3and 170 kg / m3, preferably 150 kg / m3, a thermal conductivity (X) comprised between 0.018 W m-1K1and 0.025 W m-1K-1, preferably 0.020 W m-1K1measured according to UNI EN ISO 10456:2008 standard.

[0032] The insulating material according to the invention has a series of advantageous characteristics for its use in the thermal insulation of buildings and in particular for use in thermal claddings:

[0033] - the material is fire-retardant (class Al), does not produce fumes even at high temperatures, and is self-extinguishing without dripping when exposed to flames;

[0034] - the material is hydrophobic with an absorption equal to 0.1% of its weight after 24 hours of immersion in water. This characteristic helps prevent rising damp and infiltrations;

[0035] - the material is characterized by a low heat transmission rate. Thanks to the embedding of aerogel, which has a thermal conductivity (X) of 0.018 W m-1K-1, the material according to the invention has a thermal conductivity (X) comprised between 0.018 W m-1K1and 0.025 W m-1K-1, preferably 0.020 W m-1K1measured according to UNI EN ISO 10456:2008 standard.

[0036] The insulating material according to the invention also allows high acoustic insulation thanks to the porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone, and expanded glass beads, which comprises thousands of “microchambers” filled with aerogel that constitute an effective barrier to the passage of sound. In fact, following the methodology described in UNI EN 1265:2009, values of 22 dB are obtained with a thickness of 4 cm.

[0037] The insulating material according to the invention is furthermore characterized by a low environmental impact. Its production does not require the use of flames and does not entail the emission of harmful gases. As regards disposal, unlike rock wool, which requires combustion, the material according to the invention can simply be shredded and reused several times.

[0038] The insulating material according to the invention may also comprise cements for producing articles such as panels.

[0039] In a preferred embodiment, the construction material according to the invention further comprises one or more hydraulic binders selected from the group consisting of hydraulic lime, calcite and cement, in an amount comprised between 20% and 30% by weight on the total dry weight of the material. “Total dry weight” of the material is understood to mean the total weight of the solid components (porous material, aerogel and hydraulic binder).

[0040] In a preferred embodiment, the insulating material further comprises calcite and cement, each in an amount comprised between 10% and 15% by weight on the total dry weight of the insulating material.

[0041] In a preferred embodiment, the insulating material is constituted by:

[0042] - 40% by weight of expanded pearlite,

[0043] - 37% by weight of silica aerogel,

[0044] - 13% by weight of cement, and

[0045] - 10% by weight of calcite, each on the total weight of the insulating material.

[0046] In a second aspect, the present invention relates to a method for providing the insulating material according to the invention, comprising the steps of: (i) forming a first mixture in a mixing chamber by adding under agitation at a speed comprised between 1500 rpm and 1900 rpm:

[0047] - water preheated to a temperature comprised between 30 °C and 75°C, preferably 60°C,

[0048] - silica aerogel, and

[0049] - a foaming agent, such as for example horn-hoof mixture;

[0050] (ii) closing hermetically the mixing chamber and heating the first mixture obtained in step (i) to a temperature comprised between 30°C and 75°C, preferably 60°C, mixing for a time comprised between 3 minutes and 7 minutes, preferably 5 minutes, at a speed comprised between 1500 rpm and 1900 rpm;

[0051] (iii) forming a second mixture by adding, while stirring at a rate comprised between 40 and 60 rpm, preferably 50 rpm, for a time comprised between 3 and 7 minutes, preferably 5 minutes, a porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone, and expanded glass beads;

[0052] (iv) cooling to a temperature lower than or equal to 30°C the second mixture obtained in step (iii) by adding liquid nitrogen.

[0053] In a preferred embodiment, the method according to the invention comprises the steps of:

[0054] (i) forming a first mixture in a mixing chamber by adding under agitation at a speed comprised between 1500 rpm and 1900 rpm:

[0055] - 80% water preheated to a temperature comprised between 30°C and 75°C, preferably 60°C,

[0056] - 19% silica aerogel,

[0057] - 1% foaming agent, such as for example horn-hoof mixture, each on the total weight of the first mixture;

[0058] (ii) closing hermetically the mixing chamber and heating the first mixture obtained in step (i) to a temperature comprised between 30°C and 75°C, preferably 60°C, mixing for a time comprised between 3 minutes and 7 minutes, preferably 5 minutes, at a speed comprised between 1500 rpm and 1900 rpm;

[0059] (iii) forming a second mixture by adding, while mixing at a speed comprised between 40 and 60 rpm, preferably 50 rpm, for a time comprised between 3 and 7 minutes, preferably 5 minutes, 18% by weight of a porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone and expanded glass beads, on the total weight of the second mixture;

[0060] (iv) cooling the second mixture obtained in step (iii) to a temperature lower than or equal to 30°C by adding 3 L of liquid nitrogen for each cubic meter of the second mixture.

[0061] The inventors of the present invention have surprisingly observed that the addition of 1 % of foaming agent, and in particular of horn-hoof mixture, in step (i) makes it possible to obtain a high embedding of the aerogel in the granules of porous material (in particular pearlite) and to obtain the material characterized by a X comprised between 0.018 W m-1K1and 0.025 W m ' K1.

[0062] If the desired product is granules of porous material (for example, expanded pearlite) with embedded aerogel, after the cooling step (iv) it is sufficient to dry the product at ambient temperature and pressure or to speed up the drying process by evaporating the residual water by means of an autoclave.

[0063] Alternatively, the insulating material according to the invention can be used to form articles such as for example blocks.

[0064] In a preferred embodiment, the method according to the invention further comprises the step (v) of forming a third mixture by adding to the second mixture, in a weight ratio of 2:1 respectively, water and one or more hydraulic binders selected from the group consisting of hydraulic lime, calcite and cement, where the one or more hydraulic binders are in an amount comprised between 5% and 9% by weight on the weight of the third mixture. Preferably, in step (v) calcite and cement are added in equal parts. To form a block, after adding the one or more hydraulic binders selected from the group consisting of hydraulic lime, calcite and cement, the material is placed in formwork.

[0065] In a third aspect, the present invention comprises an article comprising the insulating material according to the invention.

[0066] For example, the insulating material according to the invention can be used to produce panels, external cladding, internal cladding, floor coverings, interspaces, sandwich panels, and building walls. Alternatively, the insulating material according to the invention can be used in the form of granules as insulation in other industrial fields.

[0067] The invention will now be described with reference to the following non-limiting examples.

[0068] EXAMPLE 1 : PREPARATION OF A MATERIAL ACCORDING TO THE INVENTION

[0069] 220 L of water preheated to 60 °C were placed in a mixing chamber together with 50 kg of aerogel (AerogelZone™) characterized by a density of 50 kg / m3and X 0.018, and 53 g of hom-hoof mixture (Agritalia SRL).

[0070] The mixer was sealed hermetically and the mixture was kept under agitation for 5 minutes at a speed of 1700 rpm, maintaining the temperature at 60°C. Subsequently, 60 kg of peralit®13 expanded pearlite (Perlite Italiana SRL) were introduced in the mixer and mixing was continued at a speed of 50 rpm for a further 5 minutes.

[0071] The mixture thus formed was cooled by introducing 3 L of liquid nitrogen in the mixer.

[0072] Rapid cooling makes it possible to trap the aerogel in the pores of the expanded pearlite.

[0073] EXAMPLE 2: PROVISION OF BLOCKS OF MATERIAL ACCORDING TO THE INVENTION

[0074] To obtain blocks, 20 kg of cement, 20 kg of calcite and 80 L of water at 60°C were added to the second cooled mixture obtained in Example 1, mixing at a speed of 60 rpm for 10 minutes, and cast into two form works, each 1 m long, 50 cm wide and 50 cm high, and left to rest at 50°C for 4 hours.

[0075] The block thus obtained was subjected to the following steps: i) the block was vacuum dried in an autoclave at a temperature of 50°C for 4 hours. ii) water vapor was introduced into the autoclave until a pressure of 8106 hPa was reached, maintaining the temperature at 190°C; during this “curing” process in saturated steam, the silica of the pearlite forms calcium silicate hydrate with the calcium hydroxide, which gives the material its mechanical properties.

[0076] A block of material characterized by a density of 150 kg / m3and fire class Al was thus obtained. The material also has a X of 0.2.

[0077] In practice it has been found that the invention fully achieves the intended aim, since it provides a new insulating material that is fire-retardant and at the same time breathable and hydrophobic, with a better thermal and acoustic insulation performance than the materials currently available and which can be manufactured and disposed of with procedures that have a low environmental impact.

[0078] The insulating material thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may furthermore be replaced with other technically equivalent elements.

[0079] In practice, the materials used, as well as the dimensions, may be any according to the requirements and the state of the art.

[0080] The disclosures in Italian Patent Application No. 102024000020371 from which this application claims priority are incorporated herein by reference.

Claims

CLAIMS1. An insulating material comprising a porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone and expanded glass beads, modified with silica aerogel, characterized in that it comprises silica aerogel embedded within pores of said porous material.

2. The insulating material according to claim 1, wherein said porous material is expanded pearlite.

3. The insulating material according to claim 1, wherein said aerogel is in an amount comprised between 0.7% and 75%, preferably between 0.7% and 40% by weight on the total weight of said insulating material.

4. The insulating material according to one or more of the preceding claims, wherein said porous material is characterized by a density comprised between 120 kg / m3and 170 kg / m3, preferably 150 kg / m3, a thermal conductivity (X) comprised between 0.018 W m-1K1and 0.025 W m-1K-1, preferably 0.020 W m-1K1measured according to UNI EN ISO 10456:2008 standard.

5. The insulating material according to one or more of the preceding claims, further comprising one or more hydraulic binders selected from the group consisting of hydraulic lime, calcite and cement, in an amount comprised between 20% and 30% by weight on the total dry weight of the insulating material.

6. The insulating material according to claim 5, further comprising calcite and cement, each in an amount comprised between 10% and 15% by weight on the total dry weight of the insulating material.

7. The insulating material according to claim 6, constituted by:- 40% by weight of expanded pearlite,- 37% by weight of silica aerogel,- 13% by weight of cement, and- 10% by weight of calcite, each on the total weight of the insulating material.

8. A method for providing the insulating material according to any one of the preceding claims, comprising the steps of:(i) forming a first mixture in a mixing chamber by adding under agitation at a speed comprised between 1500 rpm and 1900 rpm:- water preheated to a temperature comprised between 30 °C and 75°C, preferably 60°C,- silica aerogel,- a foaming agent;(ii) closing hermetically the mixing chamber and heating the first mixture obtained in step (i) to a temperature comprised between 30°C and 75°C, preferably 60°C, mixing for a time comprised between 3 minutes and 7 minutes, preferably 5 minutes at a speed comprised between 1500 rpm and 1900 rpm;(iii) forming a second mixture by adding, while stirring at a rate comprised between 40 and 60 rpm, preferably 50 rpm, for a time comprised between 3 and 7 minutes, preferably 5 minutes, a porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone, and expanded glass beads;(iv) cooling to a temperature lower than or equal to 30°C the second mixture obtained in step (iii) by adding liquid nitrogen.

9. The method according to claim 8, comprising the steps of:(i) forming a first mixture in a mixing chamber by adding under agitation at a speed comprised between 1500 rpm and 1900 rpm:- 80% water preheated to a temperature comprised between 30°C and 75°C, preferably 60°C,- 19% silica aerogel,- 1% foaming agent, each on the total weight of the first mixture;(ii) closing hermetically the mixing chamber and heating the first mixture obtained in step (i) to a temperature comprised between 30°C and75°C, preferably 60°C, mixing for a time comprised between 3 minutes and 7 minutes, preferably 5 minutes, at a speed comprised between 1500 rpm and 1900 rpm;(iii) forming a second mixture by adding, while mixing at a speed comprised between 40 and 60 rpm, preferably 50 rpm, for a time comprised between 3 and 7 minutes, preferably 5 minutes, 18% by weight of a porous material selected from the group consisting of expanded pearlite, vermiculite, pumice stone and expanded glass beads, on the total weight of the second mixture;(iv) cooling the second mixture obtained in step (iii) by adding 3 L of liquid nitrogen for each cubic meter of the second mixture.

10. The method according to claim 8 or 9, wherein said foaming agent in step (i) is hom-hoof mixture.

11. The method according to any one of claims 8 or 10, further comprising the step of:(v) forming a third mixture by adding to the second mixture water and one or more hydraulic binders selected from the group consisting of hydraulic lime, calcite and cement, in a proportion of 2:1 by weight, respectively, wherein the one or more hydraulic binders are in an amount comprised between 5% and 9% by weight on the weight of the third mixture.

12. An article comprising an insulating material according to any one of claims 1 to 7.