ES2820313B2 - COVERING STRUCTURE TO WRAP EXTERIOR ENCLOSURES OF BUILDINGS - Google Patents

Description

DESCRIPTION

COVERING STRUCTURE TO WRAP CLOSURES

EXTERIOR OF BUILDINGS

TECHNICAL SECTOR

The present invention belongs to the construction sector and in particular, to the sector of manufacture of covering structures for wrapping exterior walls of buildings. It should be noted that said structure is formed by a cushion configured to be swollen by a fluid that comprises two walls which are formed by a sheet of bacterial cellulose.

BACKGROUND OF THE INVENTION

The present invention arises from the interest in improving hitherto existing processes for the manufacture of building systems in a sustainable way. In particular, it is about offering a covering system for wrapping exterior walls of buildings that is biodegradable, giving the possibility of replacing plastics such as ETFE and PTFE, which have a very high environmental impact, not only due to their production, but also for its difficult degradation.

It is therefore about offering a material that meets all the requirements established by current regulations in relation to inflatable cushions that are installed on the facades or roofs of buildings, but has the great advantage that it is obtained through a process of natural production in static cultivation, whose emissions in this process are practically zero, and it does not generate waste since it is totally biodegradable. In this way, it is possible to reduce the environmental impact associated with these processes for obtaining the materials that are currently used for inflatable cushion systems or similar systems that require the use of plastics.

In textile architecture, canvases or fabrics of plastic material are used, which have a great ecological impact in their production. However, plastic materials are leaving a large ecological footprint on our planet, and raise new sustainable alternatives must be a maxim in the development of new materials for this sector.

Based on this, there is a need to be able to find an alternative to these toxic materials both in their manufacture and in their disposal process. That is why the present invention proposes the use of bacterial cellulose to replace said plastic materials.

Bacterial cellulose is a completely natural and highly sustainable production material, which was discovered in 1886, bacterial cellulose is an organic compound generated by bacteria among other microorganisms grown in a culture medium with abundant carbon and nitrogen. (PICHETH GF, PIRICH CL, SIERAKOWSKI MR, WOEHL MA, SAKAKIBARA CN, DE SOUZA CF MARTIN AA, DA SILVA R., DE FREITAS RA (2017) Bacterial cellulose in biomedical applications: a reviwe. Int. J. Biol. Macromol. 104, 97-106).

Said material is synthesized by acetobacteria, which encompass a large number of bacteria, including gluconacetobacter, Komagataeibacter, rhizobium, agrobacterium, aerobacter, achromobacter, azotobacter, sarcin and salmonella, among others. (LUSTRI WR, GOMEZ DE OLIVEIRA BARUD H., BARUD HS PERES MFS, GUTIERREZ J., TERCJAK A. ET AL (2015) Microbial cellulosebiosynthesis mechanisms and medical applications. In M Polleto, & HL Ornaghi (Eds.) Cellulose-fundamental aspects and current trends. In tech. At Http://dx.doi.org/10).

These bacteria synthesize a layer of cellulose on the surface of their colony to protect themselves from sunlight, potential competitors, and dehydration.

Bacteria make up this cellulose by secreting nanofibers into D-glucose polymer chains linked by glycosidic bonds. In turn, the macromolecular chains are linked by glucan molecules. These macromolecules fall one on top of the other giving rise to protofibers, which accumulate on top of each other until reaching the nanometric scale. (HIRAI A., TSUJI M., HORII F. (2002) Study of band-link cellulose assembles produced by Acetobacter xylinum at 40C. Cellulose, 9, 105-113; CHEN SQ, LOPEZ-SANCHEZ P., WANG D., MIKKELSEN D., GADLEY MJ (2018) Mechanical properties of bacterial cellulose synthesis by diverse strains of the genus Komagataeibacter. Food Hydrocolloids, 81). The union of these accumulating on the surface, will form the bacterial cellulose.

This resulting cellulose has the same molecular formula as plant cellulose, except that bacterial cellulose has a unique pore network structure. This network has a high index of crystallinity or ordering of its molecules, high mechanical stability and greater purity, since it does not have lignin or pectin, existing in vegetable cellulose. (QIU Y., QIU L., CUI J., WEI Q (2016) Bacterial cellulose and bacterial cellulose-vaccarin membranes for wound healing, Mater. Sci. Eng C59, 303-309; BARUD HS REGIANI T., MARQUES RFC LUSTRI WR MESSADDEQ Y., RIBEIRO SJL (2011) Antimicrobial bacterial cellulose-silver nanoparticles composites membranes. Journal of Nanomaterials. Volume 2011. Article ID 721631).

The present invention is mainly focused on the bacterial cellulose synthesized by Komagataeibacter during the fermentation of kombucha tea. Originally from Asia, this tea consists of a green tea, inoculated with a colony of yeasts and bacteria, some of these acetobacteria. These microorganisms produce a fermentation in the tea. During this fermentation process some bacteria produce a layer of cellulose on the surface. (NGUYEN V.T. FLANAGAN B., GIDLEY M.J., DYKES G.A. (2008). Characterization of cellulose for fashion. RJTA 19, 65-69).

In the state of the art, several documents related to this cellulose material gestated in kombucha tea have been found, such as the scientific article SU MINYIM JI EUN SONG HYE RIMKIM. Production and characterization of bacterial cellulose fabrics by nitrogen sources of tea and carbon sources of sugar. Process Biochemistry Volume 59, Paris A, August 2017, Pages 26-36, which empirically establishes the tea dosage sources with the highest performance for the creation of textile material. Another article that analyzes this material is RACHEL TAMACHADO, JUNKAL GUTIERREZ, AGNIESZKA TERCJAK, ELIANE TROVATTI, FERNANDA GM, UAHIB GABRIELA DE PADUA MORENO, ANDRESA P.NASCIMENTO, ANDRESA A.BERRETA, SIDNEY JLUDRERNEIRO, S.BARERNEIRO. Carbohydrate Polymers. Volume 152, 5 November 2016, Pages 841-849, in which the differences and similarities between bacterial cellulose are discussed produced commercially and that generated in kombucha tea.

This material has been worked as a textile and exhibited in a TED talk by Suzanne Lee, where the textile character of this material and its use in fashion is disseminated.

Likewise, the use of this material for the manufacture of cigarette paper has also been described in patent application US 2019/0174815 A1.

However, to date the surprising use of this material in the construction sector has not been described.

Taking into account the state of the art where the use of this bacterial cellulose is described both in textile materials or cigarette paper, it could be assumed that the material has a low resistance, but in no case does it suggest that this type of material could be used in the construction sector, taking into account the environmental or stress conditions to which said material may be subjected in the construction sector.

The present document describes the use of the bacterial cellulose generated during the fermentation of kombucha tea for the manufacture of covering structures to wrap exterior walls of buildings.

One of the biggest problems generated in the construction industry takes place in the demolition or demolition stage of a building since normally, the elements that make up said building cannot be separated, recycled or reused in new buildings, thereby causing a large ecological footprint.

Currently there are already patents referring to this construction system, such as patent application GB2387183A, "Inflatable plastics cushion releasably held in a rigid frame", in which a rigid frame system for inflatable plastic membrane cushions is defined.

In recent years, many practices have been developed aimed at reducing this ecological footprint, such as those that aim to extend the years of use of buildings, reduce energy consumption, inside them, through passive strategies such as the use of materials that provide better insulation, while being reusable or recyclable, or using different architectural strategies that reduce heat exchange between the interior and exterior of the air-conditioned rooms of the building, like the double skin.

Thanks to the method object of the invention, construction materials are obtained with the same technical characteristics of resistance as the plastic materials currently used, and at the same time, with a practically zero associated environmental impact. The material object of the present invention is sustainable and allows it to be adapted to the needs of the construction industry, allowing the development of different covering structures to wrap the exterior walls of buildings.

Therefore, the present invention is presented as an improved alternative to the systems that currently exist on the market, since the bacterial cellulose described here is obtained by a process that barely releases emissions and whose final product is biodegradable. The fact of replacing the plastic materials that are currently used in the sector is a great advantage, effectively solving the high environmental pollution caused by manufacturing these construction parts, not only in their manufacture due to the toxic emissions implied by the I work with different plastic materials, but also the pollution caused by the difficult elimination of the waste they generate.

DESCRIPTION OF THE INVENTION

A first object of the present invention is the method for obtaining a bacterial cellulose sheet for the manufacture of a covering structure to wrap the exterior walls of buildings.

This new method is characterized because its raw material is a material that can be considered a waste material that is generated during the fermentation of Kombucha tea through the action of a symbiotic culture of bacteria and yeasts known as SCOBY. In the context of the present invention, SCOBY is an acronym for Symbiotic Colony Of Bacteria and Yeast, used in the production of various beverages and foods. This symbiotic colony includes bacterial species of the genus Acetobacter, as well as several species of Saccharomyces and other types of yeast. In relation to the present invention, within the bacteria of the genus Acetobacter, it is worth noting Komagataeibacter xylinus, which is present in Kombucha tea. Based on the foregoing and in the context of the present application, a SCOBY or Scoby Kombucha colony is defined as the symbiotic colony that has been used in the method object of the present invention, which has a gel or semi-solid appearance that is characterized in that it comprises 1012 mo./gr of the symbiotic colony described herein.

Fermented Kombucha tea is also defined in the context of the present invention, which is the sweetened tea obtained after fermentation by the action of Scoby Kombucha.

As previously indicated, during the fermentation process of Kombucha tea, a layer of bacterial cellulose is generated on the culture medium. Said layer of bacterial cellulose, which also comprises part of the Scoby Kombucha culture within its matrix, is removed from the container where the fermentation takes place and is subjected to a series of treatments, giving rise to a material that is surprisingly suitable for manufacturing. Cover structures to wrap exterior building enclosures.

To carry out the fermentation, it is necessary to dissolve sugar and tea leaves in water, which in preferred embodiments are green tea leaves, and add the symbiotic culture Scoby Kombucha.

In embodiments of the present invention, a carbohydrate source is employed, which in preferred embodiments may be sucrose and other preferred embodiments may be fructose, which are the source of the carbon necessary for cellulose synthesis.

Green tea is also added to the culture medium, which provides nitrogen as a reaction catalyst. And a regulator of pH like vinegar to keep it below 7 and prevent contamination.

To obtain bacterial cellulose, bacteria of the genus Acetobacter synthesize D-glucose polymers that are linked together by glycosidic bonds. In turn, the macromolecular chains are linked together by glucan molecules. The macromolecules fall on top of each other, giving rise to protofibers, which accumulate on the surface until they generate bacterial cellulose.

Therefore, the method for obtaining a bacterial cellulose sheet for the manufacture of a covering structure to wrap exterior walls of buildings, for building structures, is characterized in that it comprises the following stages:

Stage A: Obtaining the bacterial cellulose membrane:

To obtain the cellulose membrane, a Scoby Kombucha culture comprising 1012 mo / g is grown as described in the present document, which is in an amount, indicated in percentage by weight, comprised between 8% to 15% , and preferred form 11%, in a culture medium which in turn comprises, in percentage by weight:

• From 70% to 77% of distilled water free of chlorine and lime;

• 6% to 10% from a carbohydrate source, preferably sucrose; • From 0.5% to 1.5% of dry ground tea leaves;

• 3% to 10% fermented Kombucha tea; and

• From 3% to 8% vinegar.

In a particular embodiment of the present invention, between 100 and 300gr, preferably 200gr, of the Scoby Kombucha culture comprising 1012 mo / gr described herein is grown in a culture medium comprising:

• From 1 liter to 1.5 liters of distilled water free of chlorine and lime;

• 100 to 150 g of a carbohydrate source, preferably sucrose;

• From 7.5 to 10 grams of dry ground tea leaves, preferably green tea;

• 100 to 150ml of vinegar or Kombucha tea.

The culture is carried out at a temperature between 25 ° C and 30 ° C, since temperatures outside these thresholds can generate latency or death of the microorganisms respectively. Regarding the humidity conditions, the cultivation is carried out at a humidity lower than 70%, preferably between 60% and 70%, to avoid the gestation of competitors in the environment.

In relation to the culture time, this technical characteristic may vary since the thickness of the sample obtained is directly proportional to the culture time as a result of:

t = 7.7e

Being:

t = days of culture

e = thickness of the bacterial cellulose membrane to be obtained in millimeters.

In a preferred embodiment, so that the material can have a competent mechanical capacity to be used later for the conformation of the walls of an inflatable cushion suitable for the covering structure to wrap exterior walls of buildings, the thickness of the membrane is between 4 mm to 6 mm. To obtain a membrane of this thickness, the culture time is between 3 weeks and 3 months, in a more preferred embodiment, between 1 and 2 months, and in an even more preferred embodiment, the culture time is 1 month and half.

In a preferred embodiment of the present invention, the culture of step A of the present method is carried out in a mold that has a dimension slightly larger than the bacterial cellulose sheet to be obtained. For this reason, said mold has a depth greater than the thickness of the cellulose membrane to be obtained, but said depth cannot be less than 0.03 m, being able to have a depth of between 0.15 m to 0.3 m greater with Regarding the thickness of the bacterial cellulose membrane, to prevent contamination in the culture medium. On the other hand, the geometric shape in plane can vary depending on the way in which it is desired to obtain the cellulose membrane. In realizations Preferred of the present invention, said mold can have a rectangular shape and can have a width between 30cm and 4m, preferably between 1m and 2m and a length between 30cm and 4m, preferably between 1m and 2m.

As a result of this cultivation step, a bacterial cellulose membrane is obtained that in turn comprises part of the Scoby Kombucha, which is described herein, forming part of the matrix of said bacterial cellulose membrane and that in embodiments of the The present invention is comprised between 5% to 10% of the culture with respect to the total weight of the cellulose membrane obtained.

Stage B: Dehydration of the bacterial cellulose membrane.

Next, the bacterial cellulose membrane is subjected to a dehydration process that consists of subjecting the sheet to a temperature between 45 ° C to 70 ° C, for a period of between 36 to 50 hours, preferably 48 hours. In this way, the cellulose membrane obtained is dehydrated until it has between 1% to 10% of its humidity, and more preferably between 1% to 5%, and in an even more preferred embodiment up to 1% humidity. .

Due to this procedure, the material undergoes a shrinkage of between 80% to 95% in thickness, and in a more preferred embodiment between 85% to 90% in thickness and of around 5% to 10% in length. Therefore, the resulting thicknesses, in a preferred embodiment, would be between 0.3 and 1mm and, in an even more preferred embodiment, between 0.6 and 0.8mm.

In this way, a dehydrated bacterial cellulose sheet is obtained with dimensions suitable for the use proposed herein for said cellulose sheet.

Stage C: NaHCQ3 treatment.

Once the dehydration stage is finished, the resulting sheet is subjected to a surface treatment, except for the edges of the sheet, by which a dose of sodium bicarbonate (NaHCQ3) is applied, applying from 5g to 15g per 100cm2, being in a preferred embodiment from 8g to 13g per 100cm2, and in a an even more preferred embodiment, a dose of 9g to 11g per 100cm2, to prevent odor and improve the viability of the material for habitability.

Stage D: Wax-oil treatment.

Next, the cellulose sheet obtained from the previous treatment is impregnated with a wax-oil solution comprising between 30% to 50% beeswax and 50% to 70% coconut oil by weight with respect to the total weight of said solution, comprising in a preferred embodiment, 30% beeswax and 70% coconut oil, and in another preferred embodiment, 50% beeswax and 50% coconut oil.

Said solution, in order to be correctly applied over the entire surface of the sheet, must be heated to a temperature that can be between 80 ° C and 105 ° C and, in a more preferred embodiment, between 85 ° C and 95 °. C, and in an even more preferred embodiment, at a temperature of 90 ° C.

The amount of volume of the wax-oil solution that is applied to the cellulose sheet object of the present invention, will be the necessary to soak said sheet, which within the scope of the present invention, is considered a sufficient amount of the solution until the sheet does not accept more of said beeswax and coconut oil solution, and begins to drip, without applying to the edges of the sheet. Therefore, in the context of the present invention, the amount of beeswax and coconut oil solution that is applied to the bacterial cellulose sheet will depend on the dimensions of said sheet.

In particular embodiments of the present invention, the volume quantity of the wax-oil solution that is applied to the cellulose sheet object of the present invention, will be at least 1ml of beeswax and coconut oil solution for every 13cm2 , being in a preferred embodiment between 1ml to 20 ml per 13cm2, and in an even more preferred embodiment, from 2 to 5ml per 13cm2, without applying said solution to the perimeter of the cellulose sheet.

This last conditioning treatment gives the material greater impermeability, increases durability and improves its elasticity, and makes it more resistant against external atmospheric agents, favoring its viability for use in facade cushions.

Stage E: Drying the bacterial cellulose sheet

Finally, the cellulose sheet soaked in the mixture of beeswax and oil is allowed to dry using a perimeter drying system with catenary sagging, as shown in Figure 1 of this document. The drying temperature is 20 ° C to 35 ° C, preferably 25 ° C, for a period between 36 to 72 hours, preferably 48 hours.

In order to be able to use this material for the manufacture of covering structures to wrap exterior building enclosures, it would be expected that a pattern would have to be used, as is done with the synthetic materials used in the state of the art. , in order to give the sheet obtained the synclastic shape necessary to manufacture an inflatable cushion such as that described in the present document. However, thanks to the method of obtaining the cellulose sheet object of the invention a surprising effect is observed, which is that the cellulose sheet obtained in the stage acquires a certain shape during this drying stage, and preferably, acquires the Synclastic shape necessary to form the walls of the cushion that comprises the covering structure for wrapping the exterior enclosures of buildings that is described in the present document. For this, said cellulose sheet obtained in stage E is dried in a perimeter drying system with catenary sagging, allowing it to deform under its own weight, thus generating the curvature required by the cushion without the need to use any type of pattern.

In the context of the present invention, a synclastic shape is understood when the curvature of a surface at a given point is of the same sign in all directions. Likewise, in the context of the present invention, patterning for a textile material is understood as cutting templates in plane to obtain a certain shape, which in the case of the present invention, would be the synclastic shape.

As already indicated, thanks to the method and, therefore, to the material obtained from it, the material is not patterned to obtain the inflatable cushions described in this document.

In the context of the present invention, the bacterial cellulose membrane is defined as the membrane that is formed on top of the SCOBY culture and that is obtained after stage A of culture of the method object of the invention. As explained above, said membrane undergoes a series of subsequent treatments, which are described in stages B to E of the method object of the invention, obtaining a material with a series of technical characteristics that are described below and to which it is referred to as a bacterial cellulose sheet or sheet herein, to be able to distinguish it from the initial membrane that is not treated.

Another object of the present invention is the bacterial cellulose sheet that is obtained by the method described in this document, and that is characterized in that it can have a thickness between 0.3mm and 1.1mm, preferably between 0 , 4 to 0.8mm, and a mechanical tensile capacity of between 8MPa and 15MPa.

This relationship between thickness and breaking stress is obtained by simple tensile tests. Said tests will be carried out in accordance with the UNE-EN ISO 13934-1: 2013 standard according to point 1 "Determination of maximum force and elongation at maximum force by the strip method".

The use of bacterial cellulose sheet for the manufacture of the walls of inflatable cushions for building structures is also an object of the present invention.

It is likewise, object of the present invention, a covering structure to wrap exterior enclosures of buildings, such as roofs or facades, where said structure comprises a cushion, configured to be inflated with a fluid. Said fluid is preferably air although the cushion can also be inflated with other fluids or combinations of them, such as hydrogen or helium, with preference being given to those gases of reduced weight compared to their volume and with a high thermal insulation index, suitable for use. as a covering element for building enclosures.

This cushion comprises a first and a second wall each comprising of them, a bacterial cellulose sheet as defined in the previous embodiment, an anchor rope arranged on the perimeter of one of the sheets, then the other sheet is placed leaving the rope in the middle. The excess of perimeter sheets with respect to the rope is folded over it. This joint is reinforced by a biological weld. This joint is reinforced and sealed by a perimeter profile that frames the cushion. In turn, it consists of a fluid inlet element, configured to blow air between the two walls of the cushion.

The two walls or surfaces of the cushion are preferably rectangular, although they can have any shape as long as their perimeters are complementary, that is, the perimeters of the two walls can be assembled with the anchor rope, in the defined way, comprising two surfaces. convex once the cushion has been inflated.

The biological welding used to fix the anchor rope to the two walls of the cushion, consists of moistening, with the culture medium used in stage A of the method object of the invention, the perimeter area of said two walls, removing the Scoby Kombucha comprised in the matrix of the bacterial cellulose sheet of its dormant state, causing the remaining bacteria to produce more bacterial cellulose fibers which generate a micro-bond between both walls of the cushion and with the anchor rope. Next, the edge is dehydrated again to return the material to the sheet state, then it is treated with sodium bicarbonate (NaHC03) and, finally, it is soaked with the solution of beeswax and coconut oil, in the same conditions listed earlier in this document.

The covering structure also comprises a clamping frame, configured to hold and exert pressure on the perimeter of the two walls of the cushion, fixed by the anchor rope, said pressure exerting a hermetic seal between said two walls, where the clamping frame it is configured to be attached to a supporting surface, keeping the cushion in an inflated state.

In this way, the clamping frame can generate a pressure around the entire perimeter of the two walls to avoid any type of leakage of fluid injected between them.

The support surface on which the clamping frame can be fixed can be an enclosure of a building, such as a facade or a roof, although it can also be a structure or frame arranged on said enclosure, configured to support the frame, the fixation between said frame and the support being fixed or removable rigid, that is, it can be joined by permanent joints such as rivets or welds or removable joints such as bolts.

By means of this embodiment, when the covering structure is arranged wrapping exterior walls of buildings, the first wall is located in an internal part and the second wall in an external part visible from the outside of the building.

In one embodiment, the fluid inlet element comprises:

- a fluid conduit connected to a hole, located in one of the walls of the cushion, preferably in the second wall of the cushion; and - a valve located inside said fluid conduit;

wherein the fluid conduit is configured to insufflate a fluid between the two walls of the cushion; and where the valve is configured to block the exit of said fluid through the hole in the second wall.

The hole is made from a hole in one of the cushion walls, so that the fluid conduit with the valve can fit into said hole.

The fluid conduit is preferably made of polyethylene, and has a cylindrical shape with a diameter between 30 and 100 mm, more preferably 50 mm.

With this embodiment, when a plurality of covering structures are arranged surrounding an exterior enclosure of a building, it is possible to have a network of conduits, also preferably made of polyethylene, connected to each fluid conduit of each covering structure, by means of the which the fluid can be directed in order to insufflate the cushions comprised in said structures.

So that the fluid reaches all the structures to which the network is connected conduits, preferably, said fluid is blown at a pressure of between 250 to 500 Pa, and in an even more preferred embodiment, the pressure is 300 Pa.

In one embodiment, the covering structure comprises a pressure probe configured to measure the pressure of the fluid insufflated between the two walls of the cushion. This probe makes it possible to know the state of said cushion, allowing to regulate the entry of fluid, if necessary, or to know if said cushion has any leakage that affects its operation.

In one embodiment, the clamping frame, the first and the second wall of the cushion have a rectangular shape, and a complementary size, that is, the perimeters of the two walls can be assembled with the anchor rope, in the defined way in the first embodiment, comprising two convex surfaces once the cushion has been inflated; where the clamping frame comprises a width between 30cm to 4m, preferably between 50cm and 2m and a length between 30cm to 4m, preferably between 50cm and 2m. These sizes and shapes make the covering structure suitable to adapt to different types and sizes of facades or roofs.

In one embodiment, the clamping frame comprises:

- a support profile configured to be fixed to a support surface by means of a rigid, fixed or removable joint. Said support profile is preferably metallic, and more preferably aluminum, as it is a material resistant to the inclemencies to which it may be subjected if it forms part of an envelope of a building enclosure, in addition to its low weight.

- a sealing profile, preferably made of rubber and more preferably made of neoprene rubber, comprising two jaws arranged in the same way as the support profile to which they are assembled, said shape being, preferably, rectangular, said two jaws configured to clamp onto the perimeter of the two walls of the cushion, like a clamp;

- a gasket cover plate assembled to the support profile and configured to exert pressure on the two jaws of the sealing profile;

- a longitudinal cavity, located inside the support profile, said longitudinal cavity configured to house the anchor rope when the clamping frame is holding and exerting a clamping pressure on the perimeter of the two walls of the cushion.

In one embodiment, the cushion comprises a sheet of rice paper located between the first and second walls, and is configured to prevent sticking between them.

Also part of the invention is the use of the covering element as defined in any of the previous embodiments, to cover facades and roofs of buildings in floating, ventilated, covering structures and double skin enclosures. Said facades or roofs can comprise one or more covering structures, which can be placed one after the other, in a straight line, vertically, horizontally or inclined.

At present, the use of cellulose membranes as a textile for clothing and even for cigarette paper is known, which suggests that this material has a certain resistance, but what is really surprising is the use that is proposed in this document to cover facades and roofs of buildings in floating, ventilated, covering and double skin insulation structures.

One of the main benefits derived from the present invention is that the bacterial cellulose sheet, being a material of natural origin, is a surprising solution for the manufacture of the walls of inflatable cushions of a covering structure to wrap exterior enclosures. of buildings that have the following properties and advantages:

• It is respectful with the environment since its origin is natural,

• It presents a minimum energy consumption during its production,

• It is biodegradable in nature,

• It has mechanical properties suitable for use in inflatable cushions for façade roofs,

• It presents a high malleability which allows it to adapt various shapes which allows its use in different types of structures according to the needs of building,

• It is not necessary to pattern the material to obtain the inflatable cushions, • It has low density,

• It has a high water absorption capacity,

• The drink in which the bacterial cellulose membrane is manufactured is already produced industrially, which would favor a synergy between the food industry and the construction materials industry.

• No toxicity, no allergen and high biological compatibility.

BRIEF DESCRIPTION OF THE FIGURES

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, the following figures are attached as an integral part of said description, for illustrative and non-limiting purposes:

Figure 1: Image example of a perimeter drying system with catenary sagging of the bacterial cellulose sheet.

Figure 2: Represents a lateral view of the connection of the membrane of inflatable cushions made of textile material made by bacterial cellulose such as the one described in the present document.

Figure 3: Represents a plan view of an inflatable cushion of the object of the invention.

Figure 4: Represents a sectional view of an inflatable cushion of the object of the invention.

Below is a list of the references used in the figures:

1. Cushion;

1st First wall of the cushion;

1b Second wall of the cushion

2. Anchor rope;

3. Fluid inlet element;

4. Clamping frame;

4.1. Support profile;

4.2. Sealing profile;

4.3. Gasket cover plate;

4.4. Longitudinal cavity;

5. Pressure probe;

DESCRIPTION OF A PREFERRED EMBODIMENT

In order to contribute to a better understanding of the invention, and in accordance with a practical embodiment thereof, an example of a preferred embodiment of the present invention is attached as an integral part of this description.

Example 1: Method of obtaining a bacterial cellulose sheet suitable for the manufacture of inflatable cushions for building structures.

To obtain the bacterial cellulose membrane of the desired dimensions, a culture was prepared on a mold with a dimension slightly greater than the piece: 1.7m x 1.7m. and a depth of 4.30mm.

Stage A: Obtaining the bacterial cellulose membrane

100gr Scoby Kombucha was grown in a culture medium that included:

• 1 l of distilled water free of chlorine and lime;

• 100 gr of sucrose;

• 7.5 g of green tea;

• 100 ml of vinegar;

• 100 ml of fermented Kombucha tea.

The culture was carried out at a temperature of 28 ° C, and at a relative humidity of less than 70%. These culture conditions were maintained for 1 month and a half to obtain a 4mm membrane.

Stage B: Dehydration of the bacterial cellulose membrane.

The cellulose membrane was subjected to a dehydration process at a temperature of 65 ° C, obtaining a dehydrated cellulose membrane with a 1% humidity and a thickness of 0.5mm.

Stage C: Treatment with NaHC03.

The resulting sheet was applied 11g per 100cm2 of sodium bicarbonate (NaHC03).

Stage D: Wax-oil treatment.

The cellulose sheet obtained from the previous treatment was impregnated with a solution of beeswax and coconut oil in a proportion of 50% -50%, which was at a temperature of 90 ° C, until said sheet was completely soaked .

Stage E: Drying the bacterial cellulose sheet

Finally, the cellulose sheet soaked in the mixture of beeswax and oil was left to dry for 48 hours at a temperature of 30 ° C on a perimeter frame, allowing it to deform into a catenary under its own weight, thus generating the synclastic shape required by the cushion for use in the manufacture of the walls of the inflatable cushion to wrap exterior walls of buildings.

Example 2: Preferred realization of the cushion to wrap exterior walls of buildings

In view of the figures, and according to the numbering adopted, a preferred embodiment of an inflatable cushion (1) suitable for installation on roofs and / or facades of buildings can be observed that comprises the two walls of the cushion (1a, 1b) of 1.50m x 1.50m which are each formed by a sheet of bacterial cellulose as described herein and which is 0.5mm thick.

The walls of the cushion (1a, 1b) of 0.5mm thickness surround an anchor rope (2) where both walls of the cushion (1a, 1b) meet. For the union of both walls of the cushion (1a, 1b), one wall is placed on the other around the anchor rope (2) the other sheet and the perimeter area of the membranes is moistened, and Let it dry by sealing the pieces by biological welding, which consists of removing the material from its dormant state, generating the bacteria a micro-union between the parts. Once dehydrated again, it is soaked with the wax-oil solution.

Said walls are fixed to a 150mm aluminum support profile (4.1) through a neoprene sealing profile (4.2). The anchor rope (2) will be housed in a longitudinal cavity (4.4). The aluminum profile is compressed by means of an upper flashing plate (6) screwed on by means of flashing adjusting screws (7).

On the other hand, one of the walls of the cushion (1) is perforated and a fluid inlet element (3) is adjusted to insufflate a fluid between the two walls of the cushion (1a, 1b) comprising a 5mm fluid conduit in diameter and a valve located inside said conduit.

Finally, said fluid conduit is connected to the network of conduits and air will be blown at a pressure of 300Pa. The material has a test tensile strength capacity of 8MPa and a modulus of elasticity of 15,000MPa, therefore, neither deformation nor rupture will occur.

Claims (13)

1. Method for obtaining a bacterial cellulose sheet for the manufacture of a covering structure to wrap exterior walls of buildings characterized by the following stages: - Stage A: Obtain a bacterial cellulose membrane by cultivating 100gr to 300gr of a Scoby Kombucha colony comprising 1012 mo / gr. at a temperature between 25 ° C and 30 ° C, and a humidity of less than 70%, in a culture medium that comprises, in percentage by weight: • From 70% to 77% of distilled water free of chlorine and lime; • 6% to 10% from a carbohydrate source; • From 0.5% to 1.5% of dry ground tea leaves; • 3% to 10% fermented Kombucha tea; and • From 3% to 8% vinegar. And for a time that the relationship fulfills: t = 7.7e Being: t = days of culture e = thickness of the bacterial cellulose membrane to be obtained in millimeters. - Stage B: Dehydrate the bacterial cellulose membrane obtained in stage A by subjecting said membrane to a temperature between 45 ° C to 70 ° C for a period between 36 to 50 hours Stage C: Apply a dose between 5g to 15g per 100cm2 of NaHCO3 on the surface of the dehydrated sheet obtained in the previous stage. - Stage D: Apply a minimum of 1ml for every 13cm2 of a wax-oil solution comprising between 30% to 50% beeswax and 50% to 70% coconut oil by weight with respect to the total weight of said solution, at a temperature between 80 ° C and 105 ° C on the surface of the dehydrated sheet obtained in the previous stage, except for the perimeter edge of said sheet. - Stage E: Dry the bacterial cellulose sheet obtained in the stage with a perimeter drying system with catenary sagging at a temperature between 20 ° C to 35 ° C, for a period of 36 to 72 hours. 2. Method for obtaining a bacterial cellulose sheet, according to the preceding claim, wherein the bacterial cellulose membrane obtained in step A has a thickness between 4mm to 6mm. 3. Method for obtaining a bacterial cellulose sheet, according to any of the preceding claims, wherein the beeswax and coconut oil solution comprises beeswax and coconut oil in a 50% -50% ratio. 4. Method for obtaining a bacterial cellulose sheet, according to any of the preceding claims, wherein the bacterial cellulose sheet obtained in stage B has a relative humidity between 1% to 10% of its humidity and a thickness comprised between 0.4mm and 1mm. 5. Method for obtaining a bacterial cellulose sheet, according to any of the preceding claims, where a dose ranging from 9g to 11g per 100cm2 of NaHCO3 is applied. 6. Bacterial cellulose sheet obtained from a method according to any one of claims 1 to 5, characterized in that it has a thickness between 0.3mm and 0.8mm and a mechanical tensile capacity of between 8MPa and 15MPa. 7. Covering structure for wrapping exterior walls of buildings, characterized in that said structure comprises: - a cushion (1), configured to be inflated with a fluid, wherein said cushion comprises: or a first (1a) and a second wall (1b) each formed by a bacterial cellulose sheet as defined in claim 6; or an anchor rope (2) arranged on a perimeter, and fixed on the inside, of the two walls (1a, 1b) of the cushion, by means of a biological weld; and or a fluid inlet element (3) configured to insufflate a fluid between the two walls (1a, 1b) of the cushion (1); - a clamping frame (4), configured to hold and exert pressure on the perimeter of the two walls (1a, 1b) of the cushion (1), fixed by the anchor rope (2), said pressure exerting a hermetic seal between said two walls (1a, 1b); where the pinching frame (4) is configured to be fixed to a bearing surface, keeping the cushion (1) in an inflated state. 8. Cover structure, according to the preceding claim, wherein the fluid inlet element (3) comprises: - a fluid conduit connected to a hole located in one of the walls of the cushion, preferably in the second wall of the cushion; and - a valve located inside said fluid conduit; wherein the fluid conduit is configured to insufflate a fluid between the two walls of the cushion (1a, 1b); and where the valve is configured to block the outlet of said fluid through the hole in the second wall (1b). Cover structure according to any of the preceding claims, comprising a pressure probe (5) configured to measure the pressure of the fluid blown between the two walls (1a, 1b) of the cushion (1). 10. Cover structure, according to any of the preceding claims, wherein the clamping frame (4), the first (1a) and the second wall (1b) of the cushion (1) have a rectangular shape, and a complementary size; and where the clamping frame (4) comprises a width between 30cm to 4m and a length between 30cm to 4m. 11. Cover structure, according to any of the preceding claims, wherein the clamping frame (4) comprises: - a support profile (4.1) configured to be fixed to a support surface by means of a rigid connection; - a sealing profile (4.2), comprising two jaws arranged in the same way as the support profile (4.1) to which they are assembled, said two jaws configured to clamp on the perimeter of the two walls (1a, 1b) of the cushion ( 1); - a gasket cover plate (4.3) assembled to the support profile (4.1) and configured to exert pressure on the two jaws of the sealing profile (4.2); - A longitudinal cavity (4.4), located inside the support profile (4.1), said longitudinal cavity (4.4) configured to house the anchor rope (2) when the clamping frame (4) is holding and exerting a pressure of press on the perimeter of the two walls (1a, 1b) of the cushion (1). 12. Covering structure according to any of the preceding claims, wherein the cushion (1) comprises a sheet of rice paper located between the first and second walls, and is configured to prevent adherence between them. 13. Use of the covering structure as defined in any of claims 6 to 12, to cover facades and roofs of buildings in floating, ventilated, double skin covering and insulation structures.