Building element for a building and method for producing thereof

Abstract

The invention refers to a building element for a building or a section of a building comprising a support layer (1), and an insulating layer (2), which is arranged on said support layer (1), wherein said insulating layer (2) comprises a plurality of silk cocoons (3). In the preferred embodiments, said insulating layer (2) is arranged in a zone delimited by a top layer (4) and by said support layer (1) further comprising a plurality of interstices (5) surrounding said silk cocoons (3). The present invention also contributes to the development of insulation materials, which are proper for sustainable building elements in the construction industry. The building elements present proper thermal and acoustic properties, making them particularly suitable for being used as insulating elements.

Description

BUILDING ELEMENT FOR A BUILDING AND METHOD FOR PRODUCING THEREOF

[0001] The invention pertains to building elements for a building or a section of a building, besides methods of producing said building elements, which are used as materials for construction in general.

[0002] The construction industry is responsible for more than one-third of the total energy consumption and greenhouse gas emissions. One of the solutions to minimize this contribution can be achieved by improving building materials’ insulation properties given the great impact that these properties will have on the overall energy efficiency of buildings.

[0003] Insulation materials play a crucial role in the construction industry due to their numerous benefits and importance.

[0004] Insulation materials significantly improve the thermal efficiency of buildings by reducing heat transfer. They help to keep the interior spaces warm during colder months and cool during hotter months. By minimizing heat loss or gain, insulation reduces the need for excessive heating or cooling, thereby saving energy and reducing utility costs.

[0005] Insulation contributes to energy conservation by reducing the amount of energy required to maintain a comfortable indoor environment. By minimizing heat transfer through walls, roofs, and floors, insulation helps to lower the demand for heating and cooling systems. This, in turn, reduces the reliance on fossil fuels or electricity, leading to reduced greenhouse gas emissions and a more sustainable built environment.

[0006] Insulation enhances occupant comfort by maintaining more consistent and comfortable indoor temperatures. It helps to prevent drafts, cold spots, or excessive heat buildup, ensuring a more pleasant living or working environment. Additionally, insulation can contribute to improved indoor air quality by reducing the infiltration of outdoor pollutants, allergens, and moisture into the building.

[0007] Insulation materials with proper vapor barriers or moisture resistance properties help control condensation and moisture-related issues within buildings. By preventing the accumulation of moisture in walls, roofs, and floors, insulation minimizes the risk of mold growth, rot, and structural damage. It also helps to maintain the integrity and durability of building components.

[0008] Insulation materials with sound-absorbing properties can help reduce noise transmission between different spaces within a building or from outside sources. This contributes to acoustic comfort and privacy, making the indoor environment more peaceful and conducive to concentration and relaxation.

[0009] Several materials have caught the attention of researchers in recent years to improve buildings’ energy efficiency, such as cork, besides several synthetic foamed materials, such as extruded polystyrene (XPS), expanded polystyrene (EPS), polyurethane (PUR) foams, polyisocyanurate (PIR) foams, phenolic foams, or polyethylene (PE) foams.Technical Problem

[0010] Synthetic foamed materials are widely used as insulation in buildings due to their excellent thermal and acoustic properties, but these materials usually are not produced from recycled or renewable resources, or said materials are not recyclable themselves.

[0011] There is a need to identify insulation materials proper for building elements in the construction industry that contribute to its sustainability, besides helping in achieving green building certifications and standards by reducing the environmental impact of buildings and improving overall building performance.

[0012] There is a need for alternative building elements that are lightweight materials, having lower thermal conductivities, lower thermal diffusivities, besides having higher specific heat properties compared to state—of—the—art materials. Furthermore, there is an additional need for alternative building elements that have proper thermal insulation properties along with proper acoustic insulation properties.Solution to Problem

[0013] The present invention solves the problems regarding the need to identify insulation materials proper for building elements in the construction industry by providing a building element for a building or a section of a building comprising an insulating layer including a plurality of silk cocoons.

[0014] Unexpectedly for a person skilled in the technical field of the construction industry, the incorporation of silk cocoons in building elements improves their thermal properties, making these elements particularly suitable for insulation purposes in the construction industry, considering that the building elements according to the present invention also have a proper performance as an acoustic insulating material. Therefore, a building element for a building or a section of a building comprising an insulating layer including a plurality of silk cocoons has a combined insulating action, being proper as a thermal and acoustic insulating material.Advantageous Effects of Invention

[0015] The building elements comprising silk cocoons can be provided in flexible or rigid support layers, broadening their applications when insulating different components of a building, such as an interior wall, an exterior wall, a foundation wall, a floor, a slab floor, a ceiling, a joist space, a band joist, a roof, or a duct of a building.

[0016] The silk cocoons can improve the thermal and acoustic insulation properties of a building material comprising, for example, cement, in comparison with other commercially available solutions, for example, EPS or expanded cork agglomerate (ICB).

[0017] The thermal conductivity, thermal diffusivity, specific heat, and acoustic properties of the building elements according to the present invention are of the same order of magnitude as those of known materials, for example, EPS or ICB, making the building elements hereinafter a relevant alternative to the known materials in the prior art.

[0018] To promote an understanding of the principles of the embodiments of the present invention, reference will be made to the embodiments illustrated in the figures and the language used to describe the same. Anyway, it must be understood that there is no intention of limiting the scope of the present invention to the contents of the figures. Any alterations or later changes of the inventive features illustrated herein, and any additional application of the principles and embodiments of the invention shown, which would normally occur for one skilled in the art when reading this description, are considered within the scope of the claimed invention.Fig.1

[0019] illustrates a cross-section view of a building element comprising a rigid support layer, and an insulating layer comprising a plurality of silk cocoons;Fig.2

[0020] illustrates a cross-section view of a building element comprising a flexible support layer, a flexible top layer, and an insulating layer comprising a plurality of silk cocoons;Fig.3

[0021] illustrates a cross-section view of a building element comprising a rigid support layer, a rigid top layer, and an insulating layer comprising a plurality of silk cocoons;Fig.4

[0022] illustrates a cross-section view of a building element comprising a rigid support layer, a rigid top layer, and an insulating layer comprising a plurality of silk cocoons, wherein interstices surrounding said silk cocoons are made of the same material as the external layers, forming a continuous zone with them;Fig.5

[0023] illustrates a top view of a building element comprising a film of polyethylene (PE) / polyamide as support, and top layers;Fig.6

[0024] illustrates results regarding compressive and flexural strength, besides the variation of mass of the building elements;Fig.7

[0025] illustrates results regarding the acoustic properties of the building elements.

[0026] The present invention, as illustrated in, refers, in the first aspect, to a building element for a building or a section of a building, comprising a support layer (1), and an insulating layer (2), which is arranged on said support layer (1); wherein said insulating layer (2) comprises a plurality of silk cocoons (3).

[0027] In other embodiments, as illustrated in Figures 2 or 3, the building element further comprises a top layer (4), wherein said insulating layer (2) is arranged in a zone delimited by said top layer (4) and by said support layer (1).

[0028] Preferably, the support layer (1) or the top layer (4) is made of a material selected from the group consisting of a polymer, a copolymer, a macromolecule, a cement paste, a mortar construction material, a concrete construction material, gypsum, a clay, or combinations thereof or composites thereof. Therefore, considering the mechanical properties of the support layer (1) or the top layer (4), the building element can feature flexible or rigid properties. The selection of the material or materials for preparing the support layer (1) or the top layer (4) is guided by the targeted application of the building element with its thermal and acoustic insulation characteristics.

[0029] The building element for a building or a section of a building is configured for the erection of an interior wall, an exterior wall, a foundation wall, a floor, a slab floor, a ceiling, a joist space, a band joist, a roof, a cladding, or a duct of a building. Taking into consideration the mechanical properties of the section of a building, selecting a flexible material for preparing a support layer (1) or the top layer (4), for example, a polymer or a copolymer, is a proper choice when the building element is designed to insulate, for example, a duct or a joist space. On the other hand, rigid materials, for example, concrete or clay, are proper when the building element is connected to an interior wall, an exterior wall, a foundation wall, a floor, a slab floor, a ceiling, or a roof.

[0030] Preferably, as illustrated in Figures 3 or 4, said insulating layer (2) further comprises a plurality of interstices (5) surrounding said silk cocoons (3), wherein said interstices (5) comprise at least one of the group consisting of air, air with reduced pressure, a polymer, a copolymer, a macromolecule, a cement paste, a mortar construction material, a concrete construction material, gypsum, a clay, or combinations thereof or composites thereof.

[0031] The thermal and acoustic insulation performance of the building element according to the present invention can be boosted by stacking a plurality of layers of silk cocoons (3) in the insulating layer (2).

[0032] In other preferred embodiments, as illustrated in, a plurality of said silk cocoons (3) is embedded in an internal portion of said support layer (1), for example, when the support layer (1) is prepared from a cement paste, a mortar construction material, a concrete construction material.

[0033] In other preferred embodiments, as illustrated in, a plurality of said silk cocoons (3) is embedded in an internal portion of said top layer (4), for example, when the top layer (4) is prepared from a cement paste, a mortar construction material, a concrete construction material.

[0034] In other preferred embodiments, as illustrated in, the support layer (1), the top layer (4), and the plurality of interstices (5) surrounding said silk cocoons (3) are made of the same material and form a continuous zone, wherein said material comprises a polymer, a copolymer, a macromolecule, a cement paste, a mortar construction material, a concrete construction material, gypsum, a clay, a lime, a plaster, an adhesive, a resin, or combinations thereof or composites thereof. This embodiment is particularly useful when it is desired to conciliate the optimal thermal and acoustic insulation characteristics of the building element together with, for example, the high compressive strength or flexural strength of a cement, mortar, or concrete construction material. Even more preferably, as illustrated in, the support layer (1), the top layer (4), and the plurality of interstices (5) surrounding said silk cocoons (3) are made of a material selected from the group consisting of a cement paste, a mortar construction material, a concrete construction material, gypsum, a clay, or composites thereof. In these embodiments, said insulating layer (2) comprises preferably from 30000 to 90000 silk cocoons (3) / m3of the building element, preferably from 50000 to 75000 silk cocoons (3) / m3of the building element.

[0035] In other preferred embodiments, at least one of the support layer (1) or the top layer (4) is made of a mesh, a fabric, a polymeric film, or composites thereof, wherein the polymer of said polymeric film is a polymer selected from the group consisting of polyvinyl chloride, polycarbonate, polyethylene, polyethylene terephthalate, polypropylene, polymethyl methacrylate, polyester, polyepoxide, polystyrene, polyurethane, or composites thereof or copolymers thereof. This embodiment is particularly useful when it is desired to conciliate the optimal thermal and acoustic insulation characteristics of the building element together with flexible enclosing layers of the insulating layer (2).

[0036] Even more preferably, as illustrated in, the support layer (1) and the top layer (4) are made of a polymer selected from the group consisting of polyvinyl chloride, polycarbonate, polyethylene, polyethylene terephthalate, polypropylene, polymethyl methacrylate, polyester, polyepoxide, polyamide, polystyrene, polyurethane, or composites thereof or copolymers thereof; and said insulating layer (2) further comprises a plurality of interstices (5) surrounding said silk cocoons (3), wherein said interstices (5) comprises air with reduced pressure; and said insulating layer (2) comprises from 500 to 3000 silk cocoons (3) / m2of the building element, preferably from 1000 to 2000 silk cocoons (3) / m2of the building element. In volumetric terms, said insulating layer (2) comprises preferably from 30000 to 90000 silk cocoons (3) / m3ofthe building element, preferably from 50000 to 75000 silk cocoons (3) / m3of said building element.

[0037] The present invention refers, in a second aspect, to a method for producing a building element, as defined in the first aspect, comprising the following steps:

[0038] a) Providing a support layer (1); and

[0039] b) Arranging an insulating layer (2) on said support layer (1); wherein said insulating layer (2) comprises a plurality of silk cocoons (3).

[0040] In the preferred embodiments, the method for producing a building element, as defined in the first aspect, comprises the following steps:

[0041] a) Providing a support layer (1) and a top layer (4); and

[0042] b) Arranging the insulating layer (2) in a zone delimited by said top layer (4) and by said support layer (1).

[0043] In other preferred embodiments, the method for producing a building element, as defined in the first aspect, comprises the following steps:

[0044] a) Providing a support layer (1) and a top layer (4); and

[0045] b) Arranging the insulating layer (2) in a zone delimited by said top layer (4) and by said support layer (1) by molding, and embedding a plurality of silk cocoons (3) in at least one internal portion of said support layer (1) or internal portion of said top layer (4); wherein the support layer (1), the top layer (4), and a plurality of interstices (5) surrounding said silk cocoons (3) are made of the same material and form a continuous zone.

[0046] In the preferred embodiments, the present invention refers to a method for producing a building element comprising the steps:

[0047] a) Feeding a cement into a first mixing zone; and

[0048] b) Mixing the hydration agent, for example, water, and the cement in the first mixing zone to obtain the cement paste construction material; and

[0049] c) Molding at least one of a support layer (1) or a top layer (4), which are made of the cement paste construction material; and

[0050] d) Embedding a plurality of silk cocoons (3) in at least one internal portion of said support layer (1) or internal portion of said top layer (4).

[0051] Alternatively, in the preferred embodiments, the present invention refers to a method for producing a building element comprising the steps:

[0052] a) Feeding a cement into a first mixing zone; and

[0053] b) Mixing the hydration agent, for example, water, and the cement in the first mixing zone to obtain the cement paste construction material; and

[0054] c) Molding and embedding a plurality of silk cocoons (3) in the cement paste construction material, wherein the support layer (1), the top layer (4), and the plurality of interstices (5) surrounding said silk cocoons (3) are made of the same material and form a continuous zone.

[0055] In the preferred embodiments, the present invention also refers to a method for producing a building element comprising the steps:

[0056] a) Feeding a cement into a first mixing zone; and

[0057] b) Mixing the hydration agent, for example, water, and the cement in the first mixing zone to obtain the cement paste construction material; and

[0058] c) Feeding the cement paste construction material into a second mixing zone; and

[0059] d) Feeding a fine-grain bulk material mixture into the second mixing zone; and

[0060] e) Mixing the cement paste construction material and the fine-grain bulk material mixture in the second mixing zone to obtain a mortar construction material;

[0061] f) Molding at least one of a support layer (1) or a top layer (4), which are made of the mortar construction material; and

[0062] g) Embedding a plurality of silk cocoons (3) in at least one internal portion of said support layer (1) or internal portion of said top layer (4).

[0063] Alternatively, in the preferred embodiments, the present invention also refers to a method for producing a building element comprising the steps:

[0064] a) Feeding a cement into a first mixing zone; and

[0065] b) Mixing the hydration agent, for example, water, and the cement in the first mixing zone to obtain the cement paste construction material; and

[0066] c) Feeding the cement paste construction material into a second mixing zone; and

[0067] d) Feeding a fine-grain bulk material mixture into the second mixing zone; and

[0068] e) Mixing the cement paste construction material and the fine-grain bulk material mixture in the second mixing zone to obtain a mortar construction material; and

[0069] f) Molding and embedding a plurality of silk cocoons (3) in the mortar construction material, wherein the support layer (1), the top layer (4), and the plurality of interstices (5) surrounding said silk cocoons (3) are made of the same material and form a continuous zone.

[0070] In the preferred embodiments, the present invention also refers to a method for producing a building element comprising the steps:

[0071] a) Feeding a cement into a first mixing zone; and

[0072] b) Mixing the hydration agent, for example, water, and the cement in the first mixing zone to obtain the cement paste construction material; and

[0073] c) Feeding the cement paste construction material into a second mixing zone; and

[0074] d) Feeding a fine-grain bulk material mixture into the second mixing zone; and

[0075] e) Mixing the cement paste construction material and the fine-grain bulk material mixture in the second mixing zone to obtain a mortar construction material; and

[0076] f) Feeding the mortar construction material into a third mixing zone; and

[0077] g) Feeding a coarse-grain bulk material mixture into the third mixing zone; and

[0078] h) Mixing the mortar construction material and the coarse-grain bulk material mixture in the third mixing zone to obtain the concrete construction material; and

[0079] i) Molding at least one of a support layer (1) or a top layer (4), which are made of the concrete construction material; and

[0080] j) Embedding a plurality of silk cocoons (3) in at least one internal portion of said support layer (1) or internal portion of said top layer (4); and

[0081] k) Allowing the concrete construction material to set and cure.

[0082] Alternatively, in the preferred embodiments, the present invention also refers to a method for producing a building element comprising the steps:

[0083] a) Feeding a cement into a first mixing zone; and

[0084] b) Mixing the hydration agent, for example, water, and the cement in the first mixing zone to obtain the cement paste construction material; and

[0085] c) Feeding the cement paste construction material into a second mixing zone; and

[0086] d) Feeding a fine-grain bulk material mixture into the second mixing zone; and

[0087] e) Mixing the cement paste construction material and the fine-grain bulk material mixture in the second mixing zone to obtain a mortar construction material; and

[0088] f) Feeding the mortar construction material into a third mixing zone; and

[0089] g) Feeding a coarse-grain bulk material mixture into the third mixing zone; and

[0090] h) Mixing the mortar construction material and the coarse-grain bulk material mixture in the third mixing zone to obtain the concrete construction material; and

[0091] i) Molding and embedding a plurality of silk cocoons (3) in the concrete construction material, wherein the support layer (1), the top layer (4), and the plurality of interstices (5) surrounding said silk cocoons (3) are made of the same material and form a continuous zone; and

[0092] j) Allowing the concrete construction material to set and cure.

[0093] Preferably, the ratio between the mass of the hydration agent and cement is in the range from 0.2 to 0.7 in the cement paste construction material, more preferably, said ratio is in the range of 0.4 to 0.6.

[0094] Preferably, the ratio between the mass of silk cocoons (3) and the mass of a construction material is in the range of 0.03 to 0.05 for any construction material of the group consisting of cement, mortar, concrete, or gypsum.

[0095] Preferably, the fine-grain bulk material mixture, such as sand aggregates, has a particle size distribution from 1 mm to 4 mm in the mortar construction material.

[0096] Preferably, the ratio between the mass of fine-grain bulk material mixture and cement is in the range from 0.2 to 10.0 in the mortar construction material, more preferably from 1 to 6.

[0097] Preferably, the coarse-grain bulk material mixture has a particle size distribution from 4 mm to 25 mm in concrete construction material.

[0098] Preferably, the ratio between the mass of fine-grain bulk material mixture and coarse-grain bulk material mixture is in the range from 0.2 to 1.0 in the concrete construction material. Preferably, the ratio between the mass of the coarse-grain bulk material mixture and cement is in the range of 0.2 to 1.0 in the concrete construction material.

[0099] Table 1 illustrates some examples and weight ratios of the raw materials used in some embodiments.

[0100] Raw MaterialCompositionCementWaterFine-grain bulk material mixtureCoarse-grain bulk material mixturecement paste construction material1 kgfrom 0.2 to 0.7 kg--mortar construction material1 kgfrom 0.2 to 0.7 kgfrom 0.2 to 10 kg-concrete construction material1 kgfrom 0.2 to 0.7 kgfrom 0.2 to 1.0 kg

[0101] As it will be fully understood by a person skilled in the art, any one of the cement paste construction material, the mortar construction material, or the concrete paste construction material may comprise at least one admixture.

[0102] As previously indicated, the methods are carried out when the cementitious materials are not hardened, i.e., still fresh.

[0103] Cementitious materials take between 2 to 3 h to harden after their preparation and, when hardened, it is not possible to properly handle the mixture.

[0104] As it will be understood by a person skilled in the art, admixtures, wherein the number and amounts of such components can widely vary, may be optionally added to at least one of the mixing zones. Examples of admixtures that can be used in the construction materials of the present invention include but are not limited to, air-entraining agents, strength-enhancing amines and other strengtheners, dispersants, water reducers, superplasticizers, water-binding agents, rheology-modifying agents, viscosity modifiers, set accelerators, set retarders, corrosion inhibitors, pigments, wetting agents, water-soluble polymers, water repellents, strengthening fibers, permeability reducers, pumping aids, fungicidal admixtures, germicidal admixtures, insecticidal admixtures, finely divided mineral admixtures, alkali reactivity reducer, and bonding admixtures.

[0105] The first mixing zone, the second mixing zone, and the third mixing zone are preferably selected from the group consisting of a stationary mixer, a paving mixer, a truck mixer, a mobile volumetric mixer, a mobile batcher mixer, as it will be understood by a person skilled in the art. Said mixing zones may comprise a single mixing zone, where the methods for producing a cement paste, a mortar, and a concrete construction material are executed in the same device. Alternatively, the first mixing zone and the second mixing zone may constitute a single mixing zone for producing a cement paste and a mortar construction material. Alternatively, the second mixing zone and the third mixing zone may constitute a single mixing zone for producing mortar and concrete construction materials.

[0106] Examples and comparative tests

[0107] The silk cocoons (3) were used to prepare the building element without any treatment. Therefore, it is unnecessary to remove the chrysalis comprised in a silk cocoon.

[0108] A set of 22 silk cocoons (3) were measured to determine their average dimensions, namely a longitudinal length of 3.216 ± 0.144 cm and a transversal length of 1.811 ± 0.184 cm. The average mass of the silk cocoons (3) in the very sample was 0.633 ± 0.060 g. Moreover, a sample of 11 silk cocoons (3) had their chrysalis taken out, being obtained an average value of mass without chrysalis of 0.304 ± 0.022 g. A result recited as X ± Y, means average value ± standard deviation.

[0109] The tensile strength of a cocoon ribbon was determined by using a load cell at a speed of 50 ± 10 N / s, wherein the maximum force applied (Fmax) was 0.054 ± 0.018 kN, being obtained a tensile strength (σ) of 1.60 ± 0.37 GPa. The tensile strength of a whole cocoon was determined by using a load cell at a speed of 50 ± 10 N / s, wherein the maximum force applied (Fmax) was 0.443 ± 0.049 kN, being obtained a tensile strength (σ) of 4.57 ± 0.99 GPa.

[0110] The following materials were used as a support layer (1) and a top layer (4) to prepare a building element according to the invention: cement, and a composite layer of polyethylene / polyamide (PE / PA). The cement was commercial CEM II / A – L42.5R, certified according to the standard NP EN 197-1. The PE / PA was a commercial bag (140 mµ).

[0111] The comparative examples were prepared using XPS, extruded polystyrene balls (E_EPS), and expanded cork agglomerate (ICB). Technical specifications of the used XPS are: commercial XPS; d = 20 mm; λ = 0.033 W / mK; R = 0.6 m2K / W; and density = 30 kg / m3. Technical specifications of the used E-EPS are: commercial E_EPS; d = 20 mm; density = 15 kg / m3. Technical specifications of the used ICB are: d= 20mm; λ = 0.04 W / mK; R = 0.6 m2K / W; density = 30 kg / m3. In these recited specifications, d stands for thickness, λ stands for thermal conductivity, and R stands for thermal resistance.

[0112] Table 2 presents the set of samples prepared to carry out a comparison between a building element for insulating a building or a section of a building and insulation materials known in the prior art.

[0113] SampleCompositeInventionSC_PE / PASilk cocoon encapsulated in Polyethylene / Polyamide (PE / PA) filmSC_CPSilk cocoon embedded in Cement PasteSC_CP_SWSilk cocoon Sandwiched between Cement PasteSC_0.5CPSilk cocoon embedded in Cement PasteControlCPCement pasteCP_XPSCement paste with XPS particlesCP_S_EPSCement paste with EPS spheresXPSXPSICBICB

[0114] Sample SC_PE / PA - Silk cocoon encapsulated inPolyethylene / polyamide film

[0115] Two samples of a building element according to the invention were produced, wherein the support layer (1) and the top layer (4) are made of PE / PA film with the dimensions 100x100x20 mm. These samples were also evaluated by hot disk thermal analysis.

[0116] The PE / PA film was used to encapsulate the cocoons, which were fixed among them, and the support layer (1) and the top layer (4) by applying a vacuum to make interstices (5) surrounding said silk cocoons (3) comprising air with reduced pressure. The insulating layer (2) comprised 1625 cocoons / m2. The density of the samples was 0.102 g / cm3.illustrates a top view of a building element according to the invention comprising a support layer and a top layer made of a PE / PA film.

[0117] Sample SC_CP - Silk cocoon embedded in cement paste

[0118] To produce the samples for flexural and compressive tests (standard EN 1015-11: 2019), it was used a ratio between the mass of distilled water and cement of 0.4 in the cement paste construction material. The insulating layer (2) comprised 65000 cocoons / m3.

[0119] The building element comprises the support layer (1), the top layer (4), and the plurality of interstices (5) surrounding said silk cocoons (3) made of the cement paste material and forming a continuous zone. The building element was produced in a shape of a board with a 2.0 cm thickness and planar dimensions of 20 cm x 40 cm. The insulating layer (2) comprised 1625 cocoons / m2. The density of the samples was 0.938 g / cm3.

[0120] The results of compressive and flexural strength and the variation of mass are presented in. In Table 1 the results are compared after 28 days using as reference a cement paste.

[0121] The results of compressive and flexural strength and the variation of mass for the sample SC_CP are presented in. In Table 3 the results of compressive and flexural strength are compared after 28 days using as reference a cement paste. As expected, the results obtained for the compressive and flexural strengths show a decrease for the material SC_CP compared to the reference cement pastes, wherein this decrease occurs due to the creation of hollow spaces in the cement matrix, which are originated from the cocoons, which also led to the decrease in the weight of the sample SC_CP to practically half of the amount referred to reference cement paste as can be seen in Table 3.

[0122] SampleStrength at 28 days [MPa]Mass (g)CompressiveFlexuralSC_CP5.481.4062.00Ref. cement paste28.272.82115.80

[0123] The standard EN 13055:2016

[0022] specifies the properties of Lightweight Aggregates (LWA) and fillers derived thereof obtained by processing natural or manufactured materials and mixtures of these aggregates for concrete, mortar and grout, bituminous mixtures and surface treatments and unbound and hydraulically bound applications in construction works. This European Standard covers LWA of mineral origin having particle densities not exceeding 2000 kg / m3or lose bulk densities not exceeding 1200 kg / m3including natural LWA; LWA manufactured from natural materials; LWA manufactured from by-products of industrial processes or from recycled source materials; LWA as by-products of industrial processes. The approximately 100 kg / m3of the cocoons are far below the standard values. And for the composite SC_CP, the density is between 800 and 1600 kg / m3, and even with values of commercial products that are in the order of 1000 kg / m3.

[0124] Sample SC_CP_SW - Silk cocoon sandwiched between the cement paste

[0125] The building element comprises the support layer (1) and the top layer (4) made of cement paste, and the plurality of interstices (5) surrounding said silk cocoons (3) comprise air, as illustrated in. To produce the samples for flexural and compressive tests, it was used a ratio between the mass of distilled water and cement of 0.4 in the cement paste construction material. The building element was produced in a shape of a board with a 2.0 cm thickness and comprised 1625 cocoons / m2. The density of the samples was 0.773 g / cm3.

[0126] Sample SC_0.5CP - Silk cocoon embedded in cement paste

[0127] The building element comprises the top layer (4) made of cement paste, as illustrated in. To produce the samples for flexural and compressive tests, it was used a ratio between the mass of distilled water and cement of 0.4 in the cement paste construction material. The building element was produced in a shape of a board with a 2.0 cm thickness and comprised 1625 cocoons / m2. The density of the samples was 0.455 g / cm3.

[0128] Control samples for hot disk thermal analysis:

[0129] CP; CP_XPS; CP_S_EPS; XPS and ICB

[0130] The following materials were used to prepare control samples:

[0131] CP – The cement was commercial CEM II / A – L42.5R, certified according to the standard EN 1015-11: 2019. A ratio between the mass of distilled water and cement of 0.4 was used in the cement paste construction material.

[0132] CP_XPS – The cement was commercial CEM II / A – L42.5R, certified according to the standard EN 1015-11: 2019. A ratio between the mass of distilled water and cement of 0.4 was used in the cement paste construction material. XPS particles, in a ratio of 30% by volume, were added to the mixture.

[0133] P_S_EPS – The cement was commercial CEM II / A – L42.5R, certified according to the standard EN 1015-11: 2019. A ratio between the mass of distilled water and cement of 0.4 was used in the cement paste construction material. The ratio of XPS balls in the cement paste was identical to that of cocoons / CP, namely 1625 balls / m2.

[0134] Technical specifications of the used XPS are: commercial XPS; d = 20 mm; λ = 0.033 W / mK; R = 0.6 m2k / W; density = 30 Kg / m3.

[0135] Technical specifications of the used E-EPS are: commercial E_EPS; d = 20 mm; density = 15 kg / m3.

[0136] Technical specifications of the used ICB are: commercial ICB; d= 20mm; λ = 0.04 W / mK; R = 0.6 m2K / W; density = 30 Kg / m3.

[0137] In these recited specifications, d stands for thickness, λ stands for thermal conductivity, and R stands for thermal resistance.

[0138] Hot disk thermal analysis

[0139] The thermal conductivity, diffusivity, and specific heat tests of the samples were carried out by using the Transient Plane Source (TPS) method. The equipment used was the Hot Disk® TPS 1000 Thermal Constants Analyser (with isotropic bulk type I model), which has been widely implemented for the quick characterization of the material thermal properties. The Hot Disk 4922 sensor with associated Kapton insulation was used, with the measurement module and associated software for analysis that incorporates tools for measurements and automatic control of the external temperature. The Hot Disk 4922 sensor with a radius of 14.6 mm was placed between two uniform and identical samples having 20mm thickness. Parameters, such as output power and measurement time, were fixed at 150 mW and 10 s for samples with higher density: SC_CP; SC_CP_SW; SC_0.5_CP; CP; CP_XPS and CP_S_EPS. And 150 mW and 10s for the lightest samples: SC_PE / PA; XPS and ICB.

[0140] The results of the hot disk thermal analysis are presented in Table 4.

[0141] SampleDensity [g / cm3)]Thermal Conductivity [W / mK]Thermal Diffusivity [mm2 / K]Specific heat [MJ / m3K]SC_PE / PA0,1020,0560,6550,086SC_CP0,9380,5100,2562,065SC_CP_SW0,7730,2540,1212,290SC_0.5CP0,4550,6140,7250,847CP1,8181,8067,8310,232CP_XPS1,5700,6990,3802,113CP_S_EPS0,7900,7468,6190,089XPS0,0280,0290,7060,041ICB0,0990,0410,2520,167

[0142] The thermal conductivity of a material is a measure of its ability to conduct heat. Heat transfer occurs at a lower rate in materials of low thermal conductivity than in materials of high thermal conductivity. For insulation materials low thermal conductivity is mandatory.

[0143] Thermal diffusivity measures the rate of transfer of heat of a material from the hot end to the cold end and is related to the specific heat that measures the quantity of heat required to raise the temperature of one gram of a substance by one Celsius degree. For an insulator material, the ideal case is to have the lowest value for thermal conductivity and diffusivity and the highest specific heat, to maintain the temperature and avoid the release of heat. As a matter of comparison, the XPS and ICB are commercially available insulators.

[0144] The cement paste comprising incorporated cocoons shows better thermal properties than the normal cement reference (CP), the cement with XPS particles (CP_XPS), and the EPS spheres with identical size to the cocoons (CP_S_EPS). These results show that the silk cocoons can improve the insulation properties of a material like cement better than the commercially available XPS, with the purpose of creating a cement base insulator. The material SC_CP_SW with the presence of air on the core of the silk cocoons presents the lowest thermal diffusivity due to the air present, and lower thermal diffusivity than SC_CP. The material SC_0.5CP, with the exposed silk cocoons, also has proper outcomes and can be considered a better insulator than the cement with XPS.

[0145] By using a plastic bag PE / PA with silk cocoons it was possible to achieve thermal results that are very similar to the commercially available insulation materials. For instance, the thermal conductivity, thermal diffusivity, and specific heat of the material SC_PE / PA are of the same order of magnitude as those of XPS, whereas the thermal diffusivity and specific heat are slightly higher than those of ICB. Therefore, the material SC_PE / PA presents the capability to be used as insulation material, like XPS and ICB, with the advantage of being a more flexible product, than the abovementioned two materials.

[0146] Acoustic tests

[0147] The experimental determination of sound absorption in samples of reduced size (3 and 9 cm in diameter and thickness of 2 cm) was carried out in an impedance tube, according to EN ISO 10534-2:2001 - Transfer function method. Range: 100 Hz to 6300 Hz. Normal incidence (90º).

[0148] It can be verified inthat, the SC-CP sample presented a sound absorption improvement in almost the entire spectrum, with some emphasis on the medium frequencies.

[0149] The term “silk cocoon” refers to the cocoon of the pupal phase produced by the family of mothsBombycidae, in particular the genusBombyx, and the familySaturniidae, in particular the genusAntheraea. Among the various species of silk moths, the preferred silk cocoons are those of the speciesBombyx mori,Antheraea assamensis,Antheraea mylitta,Samia Cynthia,Philosamia ricini, orGonometa postica. Therefore, a plurality of silk cocoons comprises at least two silk cocoons. Moreover, a plurality of silk cocoons can comprise cocoons of a unique genus or family or combinations thereof.

[0150] The term “cement paste construction material” refers to the fraction of concrete that includes or is formed from a mixture that comprises one or more types of hydraulic cement, and optionally one or more types of admixtures. Freshly mixed cement paste is an approximate Bingham fluid and typically includes cement and optional admixtures. Hardened cement paste is a solid which includes hydration reaction products of cement and a hydration agent, such as water.

[0151] A plurality of types of Portland cement may be used for producing a cement paste construction material, for example, Portland cement, Portland slag cement, Portland silica fume cement, Portland pozzolan cement, Portland fly ash cement, Portland burnt shale cement, Portland limestone cement, Portland composite cement, White Portland cement, Blast furnace cement, Pozzolanic cement, Composite cement or mixtures thereof.

[0152] Preferably, the ratio between the mass of the hydration agent and cement is in the range of 0.2 to 0.7. More preferably, the said ratio is in the range of 0.4 to 0.6.

[0153] A mortar construction material can be prepared of a cement paste construction material when this is not hardened, i.e., still fresh.

[0154] The cement paste construction material takes between 2 to 3 h to harden after its preparation and, when hardened, it is not possible to properly handle the mixture.

[0155] The term “mortar construction material” refers to the paste fraction plus a fine-grain bulk material mixture but excludes a coarse-grain bulk material mixture.

[0156] The term “fine-grain bulk material mixture” refers to solid particulate materials that pass through a Number 4 sieve (ASTM C125 and ASTM C33), for example, sand particles having particle sizes less than 5 mm. More preferably, the fine-grain bulk material mixture, such as sand aggregates, has a particle size distribution from 1 mm to 4 mm.

[0157] Therefore, the fine-grain bulk material mixture is to be understood as any mineral kind, calcareous, siliceous or silico-calcareous, or other. This definition also comprises fillers or other particulate inorganic materials likely to be present in hydraulic compositions.

[0158] In the preferred embodiments according to the present invention, the ratio between the mass of fine-grain bulk material mixture and cement is in the range from 0.5 to 10, more preferably from 1 to 6. More preferably, the ratio between the mass of the fine-grain bulk material mixture and cement is in the range of 0.5 to 10.

[0159] A concrete construction material can be produced of a mortar construction material when it is not hardened, i.e., still fresh, to properly handle the mixture.

[0160] The term “coarse-grain bulk material mixture” refers to solid particulate materials that are retained on a Number 4 sieve (ASTM C125 and ASTM C33). Examples of commonly used coarse aggregates include grave, ⅜ inch rock, and ¾ inch rock. The size particle distribution in the coarse-grain bulk material mixture (9) is in the range of 4 mm to 25 mm. The normal range for the coarse-grain bulk material mixture is between 4mm and 25mm, but depending on the type of application the aggregate may be higher, as it will be understood by a person skilled in the art.

[0161] Therefore, the coarse-grain bulk material mixture is to be understood as any mineral kind, calcareous, siliceous, silico-calcareous, or other. This definition also comprises fillers, and other particulate inorganic materials likely to be present in hydraulic compositions.

[0162] As used in this description, the expressions “about” and “approximately” refer to a range in values of roughly 10% of the specified number.

[0163] As used in this description, the expression. “substantially” means that the real value is within an interval of about 10% of the desired value, variable or related limit, particularly within about 5% of the desired value, variable or related limit or particularly within about 1% of the desired value, variable or related limit.

[0164] Moreover, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from the context, the phrase “X employs A or B” is intended to mean any of the natural inclusive permutations. That is, the phrase “X employs A or B” is satisfied by any of the following instances: X employs A; X employs B; or X employs both A and B.

[0165] In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from the context to be directed to a singular form.

[0166] Further, as used herein, the term “exemplary” is intended to mean serving as an illustration or example of something and is not intended to indicate a preference.

[0167] The subject matter described above is provided as an illustration of the present invention and must not be interpreted to limit it. The terminology used to describe specific embodiments, according to the present invention, must not be interpreted to limit the invention. As used in this description, the definite and indefinite articles, in their singular form, aim to include in the interpretation the plural forms, unless the context of the description explicitly indicates the contrary.

[0168] It will be understood that the expressions “comprise” and “include” when used in this description, specify the presence of the characteristics, the elements, the components, the steps, and the related operations, but do not exclude the possibility of other characteristics, elements, components, steps, and operations from being also contemplated.

[0169] All modifications, provided that they do not modify the essential features of the following claims, must be considered within the scope of protection of the present invention.

[0170] 1. a support layer;

[0171] 2. an insulating layer;

[0172] 3. a silk cocoon;

[0173] 4. a top layer;

[0174] 5. an interstice.

Claims

A building element for a building or a section of a building, comprising a support layer (1), and an insulating layer (2), which is arranged on said support layer (1);characterized in thatsaid insulating layer (2) comprises a plurality of silk cocoons (3).The building element, according to claim 1,whereinsaid building element further comprises a top layer (4), wherein said insulating layer (2) is arranged in a zone delimited by said top layer (4) and by said support layer (1).The building element, according to the previous claim,whereinat least one of the support layer (1) or the top layer (4) is made of a material selected from the group consisting of a polymer, a copolymer, a macromolecule, a cement paste, a mortar construction material, a concrete construction material, gypsum, a clay, or combinations thereof or composites thereof.The building element, according to any one of the previous claims,whereinsaid insulating layer (2) further comprises a plurality of interstices (5) surrounding said silk cocoons (3), wherein said interstices (5) comprises at least one of the group consisting of air, air with reduced pressure, a polymer, a copolymer, a macromolecule, a cement paste, a mortar construction material, a concrete construction material, gypsum, a clay, or combinations thereof or composites thereof.The building element, according to any one of the previous claims,whereinsaid insulating layer (2) comprises a plurality of stacked layers of silk cocoons (3).The building element, according to any one of the previous claims,whereina plurality ofsaid silk cocoons (3) is embedded in an internal portion of said support layer (1).The building element, according to any one of claims 2 to 6,whereinaplurality ofsaid silk cocoons (3) is embedded in an internal portion of said top layer (4).The building element, according to any one of claims 2 to 7,whereinthe support layer (1), the top layer (4), and the plurality of interstices (5) surrounding said silk cocoons (3) are made of the same material and form a continuous zone, wherein said material comprises a polymer, a copolymer, a macromolecule, a cement paste, a mortar construction material, a concrete construction material, gypsum, a clay, a ceramic, or combinations thereof or composites thereof.The building element, according to any one of claims 2 to 8,whereinat least one of the support layer (1) or the top layer (4) is made of a mesh, a fabric, a polymeric film, or composites thereof, wherein the polymer of said polymeric film is selected from the group consisting of polyvinyl chloride, polycarbonate, polyethylene, polyethylene terephthalate, polypropylene, polymethyl methacrylate, polyester, polyepoxide, polystyrene, polyurethane, or composites thereof or copolymers thereof.The building element, according to the previous claim,whereinthe support layer (1) and the top layer (4) are made of a polymer selected from the group consisting of polyvinyl chloride, polycarbonate, polyamide, polyethylene, polyethylene terephthalate, polypropylene, polymethyl methacrylate, polyester, polyepoxide, polystyrene, polyurethane, or composites thereof or copolymers thereof; and said insulating layer (2) further comprises a plurality of interstices (5) surrounding said silk cocoons (3), wherein said interstices (5) comprises air with reduced pressure; and said insulating layer (2) comprises from 500 to 3000 silk cocoons (3) / m2of the building element, preferably from 1000 to 2000 silk cocoons (3) / m2of the building element.The building element, according to claim 8,whereinthe support layer (1), the top layer (4), and the plurality of interstices (5) surrounding said silk cocoons (3) are made of a material selected from the group consisting of a cement paste, a mortar construction material, a concrete construction material, gypsum, a clay, a ceramic, a lime, a plaster, an adhesive, a resin, or composites thereof.The building element, according to the previous claim,whereinsaid insulating layer (2) comprises from 30000 to 90000 silk cocoons (3) / m3of the building element, preferably from 50000 to 75000 silk cocoons (3) / m3of the building element.The building element, according to any one of the previous claims,whereinsaid building element is configured for the erection of an interior wall, an exterior wall, a foundation wall, a floor, a slab floor, a ceiling, a joist space, a band joist, a roof, a cladding, or a duct of a building.The building element, according to the previous claim,whereinsaid building element has thermal and acoustic insulation characteristics.A method for producing a building element, as defined in any one of the previous claims,characterized bycomprising the following steps:a) Providing a support layer (1); andb) Arranging an insulating layer (2) on said support layer (1); wherein said insulating layer (2) comprises a plurality of silk cocoons (3).The method for producing a building element, according to any one of claims 2 to 14,characterized bycomprising the following steps:a) Providing a support layer (1) and a top layer (4); andb) Arranging the insulating layer (2) in a zone delimited by said top layer (4) and by said support layer (1).The method for producing a building element, according to any one of claims 8 to 14,characterized bycomprising the following steps:a) Providing a support layer (1) and a top layer (4); andb) Arranging the insulating layer (2) in a zone delimited by said top layer (4) and by said support layer (1) by molding, and embedding a plurality of silk cocoons (3) in at least one internal portion of said support layer (1) or internal portion of said top layer (4); wherein the support layer (1), the top layer (4), and a plurality of interstices (5) surrounding said silk cocoons (3) are made of the same material and form a continuous zone.

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