ES2571995B2 - Composition for preparing prefabricated concrete and cement derivatives with bactericidal and fungicidal properties, precast concrete containing it and procedure for obtaining them - Google Patents

Abstract

The present invention relates to a composition for cement derivatives and precast concrete, precast concrete containing it and method of obtaining them. The composition of the invention has biocidal effects both in the presence and in the absence of light, since it includes organometallic components of different nature that are active under normal atmospheric conditions. Therefore, the prefabricated products of the invention can be used both inside and outside of buildings and public spaces and in both places they are able to reduce and / or eliminate bacteria, molds, allergens and other types of microorganisms.

Description

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DESCRIPTION

Composition to prepare precast concrete and cement derivatives with bactericidal and fungicidal properties. Prefabricated concrete containing it and procedure for obtaining them.

Object of the invention

The present invention relates to a composition for preparing prefabricated concrete and cement derivatives, as well as precast concrete containing it and the process for obtaining prefabricated products.

The composition of the invention has bactericidal, fungicidal and anti-allergenic effects, being able to reduce and / or eliminate the main bacterial agents causing infections and different types of fungi and molds and the major allergens for humans. This property is due to the incorporation of different organo-metallic compounds that are active in normal atmospheric conditions. Therefore, the prefabricated of the invention can be used both indoors and outdoors, mainly inside buildings, being of special interest in sanitary environments or related to human health that require high levels of hygiene.

Background of the invention

Bacteria are prokaryotic microorganisms of small size and with various morphologies. They have no nucleus, and are characterized by being protected by a cell wall composed of peptidoglycan, which gives them great resistance. The vast majority of bacteria are harmless. however, there are almost two hundred species that are pathogenic and therefore. causing various infectious diseases, which can be fatal, being the most frequent respiratory. In addition, some of them, as is the case of Pseudomonas aeruginosa, is especially opportunistic for immunosuppressed individuals, frequently becoming infected in hospitals and other health centers. Bacteria are treated with antibiotics. which inhibit the formation of the cell wall. However, the extensive use of antibiotics in agriculture and livestock, has caused many bacteria to develop resistance to them. Therefore, it is of great interest to investigate and develop new antibacterial agents that are capable of acting in the focus of the infection.

On the other hand, fungi are eukaryotic organisms that are divided between molds, yeasts and mushrooms. This group of organisms are characterized by having a cell wall composed of chitin, which, as in the case of bacteria, provides them with great resistance against fungicidal agents. Fungi have a great importance for industry, medicine and food, but nevertheless some of them produce mycotoxins and are the cause of fungal diseases of different severity in humans, animals and plants. Such fungal infections are especially common in weakened immune systems, resulting in hospitals, nursing homes, health centers, etc.

Another important group of microorganisms with adverse effects on human health are allergens. Allergens are substances that can induce a reaction of

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hypersensitivity in susceptible people who have previously been in contact with him. This hypersensitivity reaction involves the recognition of the allergen as a substance, foreign to the body, causing an excessive response of the immune system, which reacts by releasing substances that alter the body's homeostasis. The main route of contact for environmental allergens is inhalation. These types of allergens can be transported by air (aero-allergens) and inhaled through breathing. Many of the most common allergens such as pollen, mites, fungal and mold spores, epithelia, hairs, feathers and animal saliva, cockroaches and their wastes and smoke belong to this group.

At present, there are various chemical compounds widely used as bactericides. such as hydrogen peroxide, hypochlorites, iodine compounds, gaseous chlorine, quaternary ammonium salts, peracetic acid, etc. In recent research it has been discovered that silver and its compounds possess antimicrobial properties. The mechanism of action is not yet known, but it has been observed that silver causes damage to the membrane and the cytoplasm of bacteria, probably because the high reactivity of silver with sulfur causes enzymes in the cell membrane are attacked by silver. Regarding fungi, there is also a wide variety of fungicidal compounds, compounds of copper, mercury, stan, zinc, cadmium, organophosphorus, carbamates, halogenated hydrocarbons, aromatic nitro compounds, etc. Recently it has been observed that nanostructured calcium-silver phosphate powders are also capable of inhibiting the growth of fungal populations.

On the other hand, in recent years compositions have been developed for precast concrete and cement derivatives that help reduce air pollutants, mainly nitrogen oxides and volatile organic compounds. However, there is no known precast concrete or cement derivative that in addition to the aforementioned ecological properties, possesses antibacterial and fungicidal properties.

Some of the compositions for known precast concrete and cement derivatives are described in the following documents. Patent document with publication number ES2331169 describes a floor slab with capacity to degrade polluting elements or gases from the outside environment. This degradative activity only occurs under solar radiation conditions. The international application with publication number WO2004074202 also describes a pavement capable of reducing environmental pollutants by comprising in its composition a titanium dioxide photocatalyst. Similarly, the ability to remove contaminants is subject to exposure to solar radiation. The international application with publication number WO2014195533 describes prefabricated concrete and cement materials that are characterized by the ability to degrade volatile organic compounds in the absence of sunlight, and may be useful inside buildings. Finally, European Patent Publication EP2757081 describes an additive for permeable concretes that includes isisithiazolinone as a bactericide. However, no concrete or cement-based material is found that has bactericidal properties through the use of organo-metallic compounds, more preferably based on silver.

For what is known in the state of the art it is necessary and it is of great interest to develop a composition containing active components in conditions

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normal atmospheres, both in the presence and in the absence of light radiation, capable of destroying pathogenic bacteria and fungi. in both indoor and outdoor environments during daytime and nighttime hours.

The present composition object of the invention as well as precast concrete and cement derivatives derived therefrom represent an important advance against decontaminating building materials based on photocatatic reactions, since the invention is capable of destroying bacterial microorganisms and fungi in the absence. of light and inside buildings.

Description of the invention

The inventors have found a composition to manufacture prefabricated concrete and cement derivatives that allows to produce prefabricated concrete capable of destroying various pathogenic bacteria and fungal colonies in normal atmospheric conditions, both in the presence and absence of solar radiation. This is a great advantage since the precast concrete and cement derivative developed with the composition of the invention can be used as an antibacterial agent both outside and inside buildings, without any side effects, resulting in special interest in sanitary environments that require high levels of hygiene and disinfection.

There is nothing in the state of the art that suggests a composition for precast concrete and cement derivatives with bactericidal properties due to organo-metallic components.

The composition for preparing precast concrete and cement derivatives of the invention comprises silver clusters with antibacterial capacity against pathogenic bacteria. The silver clusters have a great bactericidal activity due to both their high specific surface area, and the bactericidal synergy that occurs between the silver clusters and other components of the invention. The clusters attack the cell wall and the cytoplasm of pathogenic bacteria, without the presence of light being necessary, being very useful in both indoor and outdoor environments, and of special interest in sanitary environments.

In addition to the silver clusters, the composition of the invention comprises: cement as a binder, marble, sand, silica, recycled materials and zeolites. Therefore, in a first aspect of the invention, it refers to a composition for preparing precast concrete and cement derivatives comprising:

• cement

• Sllice Arena

• Marmolina

• Recycled materials selected from the group of: glass, ceramic particles, rubber and mixtures thereof

• Zeolites

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• Silver Clusters

Silver clusters are compounds formed by a low number of silver atoms in oxidation state 0 and / or +1; specifically with a number of atoms between 1-200 atoms, preferably between 10 and 200 atoms, with a size smaller than 10 nm, preferably less than 1 nm.

The composition object of the present invention with the incorporation of silver clusters has an important bactericidal activity, which is favored by the electrostatic interaction between the bacterial cell membrane (with mostly negative charge) and the surface of the silver cluster ( with a certain positive charge character). In this way it is possible to eliminate the main bacterial agents that cause infections such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica and Legionella pneumophila. These types of materials have also been shown to be effective in eliminating one or more of the following fungi: Aspergillus Niger, Penicillium funiculosum, Paecilomyces variotii, Gliocladium virens, Chaetomium balloonsum, Aspergillus terreus, Aureobasidium pullulans, Penicillium ochrochlorisvicaderica virica, Scopulario trichlorisvicaderica virica, Scopulario trichlorisvicaderica, Scopulario trichloris, Scopulariois virica .

The composition has a bactericidal effect under normal atmospheric conditions, therefore it is used very advantageously inside buildings, especially inside buildings with sanitary functions or that have high levels of hygiene and disinfection requirements. For example, potential places of application of the invention are hospitals, health centers, nursing homes, storage rooms, laboratories and homes. Similarly, it can also be used in outdoor environments where a decrease in the bacterial agents present is desired.

The prefabricated invention may be monolayer or bilayer. The prefabricated bilayer consists of two layers, a base layer and a surface layer. The base layer comprises arid particles, recycled materials and cement, while the surface layer comprises the composition of the invention.

Precast concrete and / or cement derivatives can be used in multiple applications in the construction of buildings, such as: enclosures, foundations, linear elements, floor elements, street furniture, civil works elements, pipes, paving, modular building or Other type of specific solutions.

The present invention includes both the composition with silver clusters, as the precast concrete and cement derivatives containing it and the method of obtaining said precast concrete and cement derivatives. Therefore, a second aspect of the invention would be the process of obtaining said precast concrete or cement derivative, which comprises the following steps:

a) Pour a mixture of the components of the base layer comprising: arid particles, recycled materials and cement in a semi-dry state in a mold

b) Pouring a mixture of the components of the upper layer onto the base layer comprising the composition of the invention, which includes silver metal clusters, in a semi-dry state, so overlapping with the first mixture in the same mold

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c) Mechanical vibro-compaction process

d) Unmold the product obtained

e) Grind the surface face with a stone until a flat surface is achieved

Each of stages a) and b) is carried out through the corresponding concrete mixer, while the vibrating can be carried out by means of an electrice vibrating device. The polishing process is carried out in electric machines to which corundum stones or other abrasives for polishing are added. With the second polishing, the precast concrete flooring acquires a more natural shine where the colors of the aggregates are appreciated. The heads that carry the stones are powered by powerful electric motors. and the prefabricated dishes are carried to the heads by means of a hydraulic system in which pressure and time are controlled.

Description of the drawings

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, according to a preferred example of practical realization thereof, an set of drawings is accompanied as an integral part of said description. with illustrative and non-limiting character. The following has been represented:

FIG. 1 shows the halo of inhibition caused by the sample in the presence of a culture of Pseudomonas aeruginosa.

FIG. 2 shows the quantitative result of the Pseudomonas aeruginosa count after incubating on the sample according to JIS Z 2801-2000.

FIG. 3 shows the quantitative result of the Legionella pneumophila count after incubating on the sample according to JIS Z 2801-2000.

A preferred embodiment of the invention

As mentioned above, the first aspect of the invention relates to a composition for preparing precast concrete and cement derivatives comprising:

- cement;

- silica sand;

- marmolina;

- recycled materials selected from the group of: glass, ceramic particles, rubber and mixtures thereof;

- zeolites:

- silver clusters.

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The metallic silver clusters can agglomerate in the composition, thus losing part of their bactericidal capacity, therefore, in a preferred materialization, the silver cluster is deposited on a nano or sub-nanoparticulate support, thus decreasing the agglomeration of the clusters. Metal clusters have a great and selective activity when they are deposited in a suitable support, where the clusters are immobilized. The support-metal interactions lead to an optimal dispersion of the metal clusters, the clusters stabilizing against agglomeration processes. Possible solid supports of the silver cluster are: zeolite, sllice, ZnO, CuO, TiO2 anatase and rutile, chitosan. The crystalline structure of these supports also plays a fundamental role in the activity and selectivity of the clusters themselves. Preferably the composition of the invention comprises silver clusters supported on doped TiO2.

More preferably the silver clusters supported on doped TiO2 are in an amount between 0.01% and 10% of the total dry weight. More preferably, the silver clusters supported on doped TiO2 are in an amount between 0.01% and 4.99% of the total dry weight. More preferred, the silver clusters supported on doped TiO2 are in an amount between 0.01% and 1% of the total dry weight.

The preferred support is doped TiO2. The doped TiO2 has a synergistic effect with the silver cluster under normal atmospheric conditions, enhancing its bactericidal capacity. The presence of doped TiO2 favors the elimination and / or reduction of a large number of pathogenic bacteria both indoors and outdoors, both in the presence and in the absence of light radiation.

Preferably, the precast concrete composition comprises: cement selected from white cement or gray cement in an amount

between 1% and 85% of the total dry weight: marbles in an amount

between 1% and 30% of the total dry weight; zeolites in an amount

comprised between 0.01% and 10% of the total dry weight, resins in an amount between 0.01 and 10%. Preferably the recycled material is in a range between 1% and 15% in total dry weight. Preferably the recycled material is glass. Preferably the composition may include

pigments, and more preferably iron oxide pigments.

For the purpose of the present example, the individual values of the percentages indicated therein are such that the total composition never exceeds 100%.

Preferably the composition of the invention comprises cement selected from white cement or gray cement in an amount between 1% and 30% of the total dry weight.

Preferably the composition of the invention comprises silica sands in an amount comprised between 1% and 43% by weight.

Preferably, the composition of the invention comprises marble in an amount between 1% and 16% of the total dry weight.

Preferably the composition of the invention comprises zeolites in an amount between 1% and 10% of the total dry weight.

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Preferably the composition of the invention comprises resins in an amount between 1% and 10% of the total dry weight.

Preferably the composition of the invention comprises recycled materials selected from the group of: glass, ceramic particles, rubber and mixtures thereof in a range between 1% and 15% in total dry weight.

As already said a second aspect of the invention refers to a precast concrete comprising:

a) a base layer that includes:

- arid particles;

- resins

- recycled materials selected from the group of: glass, ceramic particles, rubber and mixtures thereof; Y

- cement and;

b) an upper layer on the base layer comprising the composition of the invention.

Preferably the base layer has a thickness between 0.001 mm and 550 mm, more preferably between 0.001 mm and 20 mm. Preferably the arid particles are in a proportion between 1% and 80% in total dry weight of the base layer, more preferably between 75% and 80% in total dry weight of the base layer.

In addition, the base layer may also include a water repellent that is in a range between 0.15% and 0.30% in total dry weight of the base layer, which acts as a reducing element for water filtration, being more preferably the range between 0.20% and 0.28% in total dry weight of the base layer. The base layer may also include a fluidizing additive which is in a range between 0.15% and 0.30% by total dry weight of the base layer, more preferably between 0.20% and 0.28% by weight dry total of the base layer that allows to reduce the amount of water required in the manufacturing process of the precast concrete. Preferably the base layer comprises a hydrophobe and a fluidizing agent.

The thickness of the surface layer of the precast concrete flooring is between 0.001 mm and 20 mm, preferably between 1 mm and 10 mm.

Finally, the procedure for obtaining the precast concrete comprising one or more of the following stages of:

a) pouring a mixture of the components of the base layer comprising: arid particles; recycled materials selected from the group of: glass, ceramic particles, resins, rubber and mixtures thereof; and cement in a semi-dry state in a mold;

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b) pouring a mixture of the components of the top layer comprising the composition for preparing cement derivatives and precast concrete of the invention in a semi-dry state in an overlapping manner with the first mixture in said mold;

c) vibrate the mixture of the two discharges from stage a) and b);

d) cook the mixture between 800 and 1,500 ° C;

e) unmold the product obtained;

f) roughing the surface face with a stone until a flat surface is achieved;

g) polish with a finer stone than the stone used in stage f) of

rough.

Preferably, the roughing stage is performed with a corundum or similar grain stone from 24 mm to 60 mm, and polishes the prefabricated all possible deformations leaving a smooth face free of imperfections. Preferably, the polishing step is performed with a stone from 80 mm to 300 mm, which brightens the surface and leaves it ready to be placed.

Examples

Example 1. Preparation of a slab with the composition of the invention

The components of the base layer are mixed: arid particles, glass, resins and cement to complete 100% in a semi-dry state and are poured into a mold of a slab of dimensions of 50 mm by 10 mm.

A mixture of the components of the surface layer which are cement 19%, silica sand 43%, silver cluster 2%, marble 16%, resin 3%, glass 7%, zeolites 10% is added to this layer. The surface layer has a thickness of 7 mm. The mixture is made to vibrate, it is demoulded, and finally it is rough and polished.

Example 2. Bactericidal effect of pavement slab of Example 1

In the present example, the pavement slab sample from Example 1 was tested, to assess the bactericidal capacity against Pseudomonas aeruginosa and Legionella pneumophila strains, the JIS Z 2801-2000 test standard.

A standardized amount of 1.2x105 microbial population was counted and covered with a plastic cover to prevent evaporation during a contact time of 24 h. The pieces were incubated during this period at 35.1 ° C and 90% humidity. Once completed, the existing microbial population was collected using a physiological saline phosphate buffer diluent and counted. The test was performed in duplicate.

Figure 1 shows the halo of inhibition caused by the sample in the presence of a culture of Pseudomonas aeruginosa.

The results of the sample (slab of Example 1) are shown in the table.

Table 1 Bactericidal effect against Pseudomonas aeruginosa: Reduction of 2.04 according to JIS Z 2801-2000, greater than 90%

 Name of

 Diluc tones Count Reduction

 produced

 10 ° 101 10- * 10J 10 "1

 White without

 > 330> 330> 330 37 4 A = 3.8 10s

 incubate

 > 330> 330> 330 39 4

 White

 > 330> 330 125 12 1 B = 1.2 10s

 incubated

 > 330> 330 112 11 1

 30 QA

 115 11 1 0 0 01.1 103 2.04

 114 12 1 0 0

Reduction R = pog (B / A) -log (C / A)] = [log (B / C)]

Table 2 Bactericidal effect against Legionella pneumophila: Reduction of 1.66 according to JIS Z 2801-2000, greater than 75%

10

 Name of

 Dilutions Count Reduction

 produced

 10 ° 10- ’10" 2 10-3 lO- *

 White without

 > 330> 330 126 12 1 A = 1.2 10s

 incubate

 > 330> 330 115 10 1

 White

 > 330> 330 49 5 0 B = 5 104

 incubated

 > 330> 330 52 5 0

 300A

 107 10 1 0 0 01.1 103 1.66

 105 8 0 0 0

Claims (16)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 1. Composition for preparing precast concrete and cement derivatives comprising: • cement; • silica sand; • marmolina; • recycled materials selected from the group of: glass, ceramic particles, rubber and mixtures thereof; • zeolites and; • silver clusters. 2. Composition according to revindication 1 characterized in that the silver clusters are supported on doped TiO2. 3. Composition according to revindication 2 characterized in that the silver clusters supported on doped TiO2 are between 0.001% and 10% of the total dry weight. 4. Composition according to revindication 3 because the silver clusters supported on doped TiO2 are between 0.001% and 4.99% of the total dry weight. 5. Composition according to revindication 4 because the silver clusters supported on doped TiO2 are between 0.001% and 3% of the total dry weight. 6. Composition according to any of the preceding claims comprising white and / or gray cement in an amount between 1% and 40% dry weight. 7. Composition according to any of the preceding claims comprising silica sands in an amount comprised between 1% and 50% dry weight. 8. Composition according to any of the preceding claims comprising marmoline in an amount comprised between 1% and 20% by dry weight. 9. Composition according to any of the preceding claims comprising zeolites in an amount comprised between 1% and 10% by dry weight. 10. Composition according to any of the preceding claims comprising recycled materials selected from the group: glass, ceramic particles, rubber and mixtures thereof in an amount between 1% and 15% dry weight. 5 10 fifteen twenty 25 30 35 40 Four. Five fifty 11. Composition according to any of the preceding claims comprising resin in an amount comprised between 1% and 10% by dry weight. 12. Composition according to any of the preceding claims comprising a hydrophobe and / or a plasticizer additive and / or a pigment. 13. Precast concrete comprising a) a base layer that includes: - arid particles; - resins - recycled materials selected from the group of: glass, ceramic particles, rubber and mixtures thereof; Y - cement and; b) an upper layer on the base layer comprising the composition of any of claims 1-12. 14. Precast concrete according to revindication 13 characterized in that the thickness of the top layer is between 0.001 mm and 20 mm. 15. Precast concrete according to any of claims 13-14 comprising in the base layer a hydrophobe and / or a plasticizing additive. 16. Procedure for obtaining the precast concrete according to any of claims 13-15 comprising the steps of: a) pouring a mixture of the components of the base layer comprising: arid particles; recycled materials selected from the group of: glass, ceramic particles, resins, rubber and mixtures thereof; and cement in a semi-dry state in a mold; b) pouring a mixture of the components of the top layer comprising the composition for preparing cement derivatives and precast concrete of the invention in a semi-dry state in an overlapping manner with the first mixture in said mold; c) vibrate the mixture of the two discharges from stage a) and b); d) unmold the product obtained; e) roughing the surface face with a stone until a flat surface is achieved; f) polish with a finer stone than the stone used in step e) of roughing.