conductive inorganic binder composition

Abstract

An inorganic binder composition, particularly a conductive inorganic binder composition, comprises at least one inorganic binder, a carbon nanotube, and carbonaceous particles, wherein the carbonaceous particles are chemically and / or physically different from the carbon nanotube.

Description

[Technical Field]

[0001] The present invention relates to inorganic binder compositions, particularly conductive inorganic binder compositions. Furthermore, the present invention relates to cured articles and objects based on inorganic binder compositions. Moreover, the present invention relates to a method for heating cured articles or objects, and to the use of inorganic binder compositions or cured articles as antistatic flooring and / or as heating elements for buildings or infrastructure structures for structural monitoring, electromagnetic shielding, electrostatic discharge protection, corrosion prevention of steel-reinforced concrete structures. [Background technology]

[0002] For example, conventional inorganic binder compositions such as cement-based mortar or concrete are rather good electrical insulators with high electrical resistivity.

[0003] For example, the electrical resistivity of concrete can vary depending on several factors, such as the type of concrete mix, moisture content, temperature, and the presence of additives or reinforcing materials. However, as a general guideline, the electrical resistivity of typical concrete is approximately 10 4 ~10 7 It is in the range of Ωm.

[0004] In contrast, conductive concrete, also known as smart concrete, is a special type of concrete that has been improved to have higher conductivity or lower electrical resistivity than conventional concrete. Conductive concrete can be used as antistatic flooring and / or as a heat source in buildings or infrastructure structures for structural monitoring, electromagnetic shielding, electrostatic discharge protection, and corrosion protection of steel-reinforced concrete structures.

[0005] The fundamental principle behind conductive inorganic binder compositions lies in integrating conductive additives, such as carbon black or metal particles, into the inorganic binder composition. These additives establish a conductive network within the inorganic binder composition, thereby allowing electric current to flow through the material.

[0006] In this regard, U.S. Patent Application Publication No. 2019 / 0218144 A1 (Pellenq et al.) describes, for example, a cement composite material filled with electrically conductive nanoporous carbon. The nanoporous carbon-filled cement composite material can be used in a wide variety of different applications, such as structural super-capacitors as energy solutions for self-sustaining homes and other structures, heated cement for de-icing paved roads, or as insulation for the lowest part of a house against capillary rise, protection of concrete against freeze-thaw (FT) or alkali-silica reaction (ASR) or other crystallization degradation processes, as well as as conductive cables, wires, or concrete traces. The nanoporous carbon described is, for example, carbon black, multi-walled carbon nanotubes, graphene flakes, activated porous carbon, and saccharose coke.

[0007] Similarly, International Publication No. 01 / 72657A1 (National Research Council of Canada) describes conductive concrete suitable for commercial and mass production. In this conductive concrete, carbonaceous particles are used as the conductive phase to achieve concrete with a low resistivity of 2 Ωcm. The conductive carbonaceous particles used as the conductive phase may be carbon from many different sources and may take the form of lumps or fibers. A preferred conductive carbonaceous particle is powdered coke, a by-product of steel smelting.

[0008] Furthermore, International Publication No. 2012 / 143221A1 (Henkel) describes compositions comprising 5 to 90% by weight of at least one inorganic binder, 0.1 to 10% by weight of soot, and 0.1 to 15% by weight of carbon fiber, based on the total weight of the composition. These compositions can be used, in particular, to manufacture flat heating elements for electrically heated surfaces of floors, walls, or ceilings.

[0009] However, well-known conductive inorganic binder compositions are not entirely convincing. In particular, when used in heating applications, it takes a considerably long time to reach the desired temperature using these compositions. [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] Therefore, the development of improved solutions that at least partially overcome the aforementioned shortcomings is still needed. [Means for solving the problem]

[0011] One of the objectives of the present invention is to provide improved solutions for conductive inorganic binder compositions. In particular, these solutions should enable the production of conductive inorganic binder compositions that can be cured more efficiently at the fastest possible heating rate. Furthermore, these solutions should offer as much flexibility as possible.

[0012] Surprisingly, it has been found that these objectives can be achieved using the composition described in claim 1. In particular, the present invention relates to an inorganic binder composition, especially a conductive inorganic binder composition, comprising at least one inorganic binder, carbon nanotubes, and carbonaceous particles, wherein the carbonaceous particles are chemically and / or physically distinct from the carbon nanotubes.

[0013] The present invention's combination of carbon nanotubes and carbonaceous particles results in a synergistic interaction between two different types of carbon-based materials. In particular, the heating rate of cured articles produced from the inorganic binder composition of the present invention is dramatically improved compared to similar compositions containing only one type of carbon-based material.

[0014] In particular, using the composition of the present invention, a cured article can be manufactured that can be heated from room temperature to a desired temperature of 100°C by applying a voltage of only 40 volts (V) for less than 10 minutes. Using only one type of carbon-based material, but under otherwise identical conditions, it already takes approximately 50 minutes to reach a temperature of 80°C.

[0015] Furthermore, the heating process using a cured article based on the inorganic binder composition of the present invention is highly advantageous in terms of power consumption.

[0016] While not intended to be constrained by theory, it is believed that combining different carbon-based materials significantly increases the number of contact points between conductive particles in the inorganic binder composition. This forms a percolation network, resulting in a continuous connection between the inorganic binder composition and percolated conductive particles to a degree sufficient to make the composition conductive, enabling highly efficient resistive heating.

[0017] Furthermore, the inorganic binder compositions of the present invention can be realized with different properties, for example, by selecting a specific inorganic binder and, optionally, by adding aggregates and / or additives. This allows for a wide range of control over the processing characteristics and properties of cured articles made from the compositions of the present invention.

[0018] In particular, the composition of the present invention or a cured article produced therefrom can be used for very different applications, especially (i) heating of buildings and infrastructure using, for example, floor heating screeds and / or heating panels, (ii) de-icing and snow melting on roads, bridges, footpaths, stairs, roofs, and runways of airports, (iii) electrical grounding and earthing, (iv) electrostatic discharge (ESD) protection, (v) structural monitoring of buildings and infrastructure, and (vi) electromagnetic shielding.

[0019] Overall, the inorganic binder composition of the present invention is very beneficial and can be used for a number of applications.

[0020] A further aspect of the present invention is the subject matter of the further independent claims and / or is outlined throughout this description and the dependent claims.

Mode for Carrying Out the Invention

[0021] A first aspect of the present invention is directed to an inorganic binder composition comprising at least one inorganic binder, carbon nanotubes, and carbonaceous particles, wherein the carbonaceous particles are chemically and / or physically different from the carbon nanotubes, particularly a conductive inorganic binder composition.

[0022] The "inorganic binder composition" used in the context of the present invention includes mixtures containing at least one inorganic binder. The inorganic binder composition can further include aggregates and / or other additives, which is also preferred in the context of the present invention.

[0023] The inorganic binder composition of the present invention need not essentially contain water and can exist in a dry form. Similarly, the inorganic binder composition of the present invention can contain some or all of the mixing water and can exist in a fluid or cured form.

[0024] In particular, in the dry state, the inorganic binder composition may not be conductive. Mixing of the inorganic binder composition with mixing water and / or curing of the inorganic binder composition may be required to obtain a conductive inorganic binder composition.

[0025] For this purpose, the term "particles" specifically refers to solids having an average particle size of less than 1000 μm, and especially less than 500 μm. Particle size, its distribution, or average particle size can be determined, in particular, by laser light scattering, preferably in accordance with the standard ISO 13320:2009. Specifically for this purpose, the Mastersizer 2000 apparatus from Malvern Instruments GmbH (Germany) can be used together with the Hydro 2000G dispersion unit and the Mastersizer 2000 software. The average or average particle size in this case corresponds to the D50 value (50% of particles are smaller than the specified value, and therefore 50% are larger).

[0026] Carbon nanotubes (CNTs) are essentially carbon tubes with a diameter typically in the range of less than 100 nm.

[0027] In particular, carbon nanotubes are selected from single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and / or nanotubes having an undetermined carbon wall structure.

[0028] In particular, although not manufactured by this method, single-walled carbon nanotubes can be imagined as being formed by cutting out a two-dimensional hexagonal lattice of carbon atoms and rolling it up along one of the Bravais lattice vectors of the hexagonal lattice to form a hollow cylinder. Multi-walled carbon nanotubes typically consist of nested single-walled carbon nanotubes that are weakly bonded to each other in a tree-ring-like structure.

[0029] In contrast to carbon nanotubes, carbon fibers are solid strands of carbon atoms. Specifically, carbon fibers consist of loosely packed layers of graphite sheets stacked parallel to each other. Thus, although based on the same type of atom, namely carbon, carbon fibers are structurally very different from carbon nanotubes. Typically, individual carbon fibers have a diameter of about 5-10 μm.

[0030] The carbon nanotubes particularly preferred for use in the compositions of the present invention are single-walled carbon nanotubes. These types of carbon nanotubes have been found to be very beneficial in that they increase the conductivity of the inorganic binder composition. However, other types of carbon nanotubes can also be used.

[0031] Carbon nanotubes preferably have an average outer diameter of about 0.4 to 25 nm, particularly 0.6 to 10 nm, for example 1 to 5 nm, and especially 1.2 to 2.0 nm. The outer diameter can be measured, for example, by light absorption in accordance with the standard ISO / TS 10868:2017.

[0032] Preferably, the carbon nanotubes have an average length of at least 0.5 μm, particularly at least 1 μm, particularly at least 4 μm, and particularly at least 5 μm. For example, the carbon nanotubes have an average length of 0.5 to 5,000 μm, particularly 1 to 1,000 μm, for example, >5 to 100 μm. The length of the carbon nanotubes can be measured by standard atomic force microscopy (AFM).

[0033] In particular, the average aspect ratio, i.e., the average ratio of the length of the carbon nanotube to its diameter, is at least 100, especially at least 1,000, especially at least 2,500, for example at least 3,000.

[0034] The specific surface area of ​​carbon nanotubes is preferably at least 100 m². 2 / g, especially at least 200m 2 / g, especially at least 300m 2 / g, for example, 300-1,000m 2 / g, or 300-600m 2 The specific surface area is / g. The specific surface area can be determined by BET surface area analysis using N2 in a conventional method well known to those skilled in the art.

[0035] Carbon nanotubes having such dimensions and properties have been found to be particularly beneficial with regard to an efficient increase in conductivity in an inorganic binder composition used in combination with further carbonaceous particles.

[0036] Very preferably, the carbon nanotubes have a G / D ratio > 10, particularly > 50, particularly > 70, for example > 90. The G / D ratio is defined as the intensity ratio of the peak near 1590 cm -1 (G band) in the Raman spectrum of the carbon nanotubes to the intensity of the peak near 1350 cm -1 (D band). The peak near 1590 cm -1 is due to the in-plane vibration of the six-membered rings typical of carbonaceous materials. The peak near 1350 cm -1 is due to defects in the carbon nanotubes. The intensity G / D ratio can be used as an indicator of the amount of defects in the carbon nanotubes. The larger the G / D ratio, the fewer the defects present in the carbon nanotubes.

[0037] Carbon nanotubes having the above-defined G / D ratio have a low density of defects, which has been found to be beneficial for improving the conductivity of the inorganic binder composition and providing a cured article capable of being heated by resistive heating.

[0038] Preferably, the carbonaceous particles are selected from any carbon material in which a population of carbon atoms involved in the sp 2 hybridization mechanism is dominant.

[0039] Particularly preferred carbonaceous particles are selected from carbon black, graphene flakes, multi-walled carbon nanotubes, coke particles, and / or activated carbon. Very preferably, the carbonaceous particles are selected from carbon black. The carbon black is particularly carbon black according to CAS 1333-86-4.

[0040] It has been found that carbonaceous particles of this type, particularly carbon black, are beneficial in combination with carbon nanotubes, particularly single-walled carbon nanotubes.

[0041] The carbonaceous particles are preferably 20-380 kg / m³ 3 , especially 50-150 kg / m 3 It has a bulk density. Bulk density is defined as the mass of a number of particles in a material divided by the total volume they occupy.

[0042] In particular, carbonaceous particles have an average particle size of 10-500 nm, especially 20-300 nm, especially 25-100 nm, especially 30-70 nm, or 40-60 nm.

[0043] Carbonaceous particles of this size and property have been found to be particularly beneficial to the present invention when used in combination with carbon nanotubes.

[0044] According to a very preferred embodiment, the carbonaceous particles are selected from carbon black having a particle size of 25–100 nm in particular, and the carbon nanotubes are single-walled carbon nanotubes having an average length of at least 5 μm and an average diameter of about 1.2–2.0 nm.

[0045] Preferably, the ratio of carbon nanotubes, particularly single-walled carbon nanotubes, to the total weight of the total dry components of the inorganic binder composition is 0.2 to 1000 ppm, preferably 1 to 900 ppm, more preferably 10 to 500 ppm, and particularly 100 to 400 ppm. In this context, "ppm" refers to the number of parts per million (10) based on weight. -6 This means that 1 ppm is equal to 0.0001% by weight.

[0046] In a very preferred embodiment, carbon nanotubes are used and / or provided in the form of a dispersion in a liquid, particularly in water. This facilitates further distribution of the nanotubes into the inorganic binder composition in a very efficient manner.

[0047] In particular, the ratio of carbon nanotubes in the dispersion, relative to the total weight of the dispersion, is 0.01–2% by weight, especially 0.1–1% by weight, or 0.2–0.6% by weight.

[0048] A preferred inorganic binder composition comprises at least one inorganic binder, single-walled carbon nanotubes having an average outer diameter of about 0.4 to 25 nm, and carbon black, preferably carbon black having a particle size of 25 to 100 nm.

[0049] A preferred inorganic binder composition comprises at least one inorganic binder, single-walled carbon nanotubes having an average length of at least 5 μm and an average diameter of about 1.2 to 2.0 nm, and carbon black, preferably carbon black having a particle size of 25 to 100 nm.

[0050] Furthermore, a dispersant, in particular an anionic surfactant selected from, for example, alkylbenzene sulfonates, such as sodium dodecylbenzenesulfonate, and / or alkyl ether sulfates, such as sodium laureth sulfate, may be present in the dispersion. In particular, the ratio of the dispersant in the dispersion based on the total weight of the dispersion is 0.1 to 5% by weight, especially 0.5 to 3% by weight or 1 to 2% by weight.

[0051] Based on the total weight of the dispersion, the proportion of liquid, particularly water, in the dispersion is particularly 93-99.9% by weight, particularly 95-99% by weight, and particularly 97.5-98.5% by weight.

[0052] Preferably, the ratio of the dispersion to the total weight of the total dry components of the inorganic binder composition is 0.005 to 1% by weight, particularly 0.01 to 0.5% by weight, for example, 0.01 to 0.2% by weight or 0.02 to 0.1% by weight.

[0053] The ratio of carbonaceous particles, particularly carbon black, to the total weight of all dry components of the inorganic binder composition is preferably 0.5 to 10% by weight, particularly 2 to 6% by weight, for example, 3 to 5% by weight or 3.5 to 4.5% by weight.

[0054] In particular, the weight ratio of carbonaceous particles to carbon nanotubes is 10–1,250,000, especially 50–125,000, especially 75–10,000, or 90–1,000.

[0055] In particular, the advantages of the present invention are realized by using such a ratio of carbon nanotubes and carbonaceous particles.

[0056] In particular, the ratio of carbonaceous particles to carbon nanotubes is selected such that a continuous percolation network of carbonaceous particles and carbon nanotubes is formed or present in the inorganic binder composition. In other words, in this case, the carbonaceous particles and carbon nanotubes form a continuous percolation network in the inorganic binder composition. This is especially true when the inorganic binder composition is in a cured state.

[0057] A percolation network is formed by the continuous connection of carbonaceous particles and carbon nanotubes in an inorganic binder composition, where percolation occurs to a degree sufficient to make the composition conductive. Percolation theory can be used to explain the conductive behavior of composite materials consisting of conductive particles and an insulating matrix. As the content of carbonaceous particles and carbon nanotubes gradually increases, a transition from insulator to conductor occurs in the inorganic binder composition. Percolation occurs and current can flow when there are pathways of carbonaceous particles and carbon nanotubes that allow the source electrode to connect to the drain electrode.

[0058] A preferred inorganic binder composition comprises at least one inorganic binder, carbon nanotubes, and carbon black, wherein the ratio of carbon nanotubes, particularly single-walled carbon nanotubes, is 100 to 700 ppm, and the ratio of carbon black is 0.1 to 1% by weight, with each ratio based on the total dry weight of the inorganic binder.

[0059] A preferred inorganic binder composition comprises at least one inorganic binder, carbon nanotubes, and carbon black, wherein the ratio of carbon nanotubes, particularly single-walled carbon nanotubes, based on the total weight of all dry components of the inorganic binder composition is 0.2 to 1000 ppm, preferably 1 to 900 ppm, more preferably 10 to 500 ppm, and particularly 100 to 400 ppm; and the ratio of carbon black, based on the total weight of all dry components of the inorganic binder composition, is 3.5 to 4.5% by weight.

[0060] In the context of the present invention, "inorganic binder" refers to a binder that reacts in the presence of water through a hydration reaction to form a solid hydrate or hydrate phase, particularly an inorganic binder. This may be, for example, a hydraulic binder (e.g., cement or hydraulic lime), a latent hydraulic binder (e.g., slag or blast furnace slag), a pozzolanic binder (e.g., fly ash, truss, or rice husk ash), or a non-hydraulic binder (gypsum or plaster). Mixtures of various binders are also possible.

[0061] In particular, the inorganic binder includes a hydraulic binder, preferably cement. Cement having a cement clinker content of 35% by weight is particularly preferred. Preferably, the cement is type CEM I, CEM II, CEM III, CEM IV, CEM V (according to standard EN 197-1), or calcium aluminate cement (according to standard EN 14647:2006-01), or calcium sulfoaluminate cement, or a mixture thereof. In particular, the cement is type CEM I, CEM II, calcium sulfoaluminate cement, or a mixture thereof. Naturally, cement manufactured in accordance with other relevant standards, such as relevant ASTM or Chinese standards, is also suitable. Furthermore, white cement can be used as the inorganic binder of the present invention.

[0062] The proportion of hydraulic binder in the total inorganic binder is preferably at least 5% by weight, more preferably at least 20% by weight, even more preferably at least 35% by weight, and particularly at least 65% by weight. In a more advantageous embodiment, the inorganic binder consists of at least 95% by weight of hydraulic binder, particularly cement.

[0063] However, it may be advantageous for the inorganic binder to include another binder in addition to, or instead of, the hydraulic binder. These are, in particular, latent hydraulic binders and / or pozzolanic binders. Suitable latent hydraulic binders and / or pozzolanic binders are, for example, slag, fly ash, and / or silica fume. Similarly, the binder composition may include inert substances such as, for example, limestone powder, quartz powder, and / or pigments.

[0064] Furthermore, the inorganic binder of the present invention, in particular cement, may include cement modifiers selected from the group consisting of grinding aids, strength modifiers, stimulants, accelerators, plasticizers, and fluidizers. The cement modifiers can be mutually ground together with the inorganic binder during grinding. They can also be mixed with the similarly ground inorganic binder.

[0065] Preferably, the inorganic binder is selected from cement, hydraulic lime, fly ash, slag, silica fume, and / or gypsum.

[0066] In addition to the inorganic binder, the inorganic binder composition according to the present invention preferably includes aggregates and / or additives. If present, the aggregates and / or additives are chemically and / or physically distinct from the carbonaceous particles and carbon nanotubes.

[0067] Preferably, the inorganic binder composition of the present invention includes aggregate. The aggregate may be any material that is non-reactive in the hydration reaction of the inorganic binder. The aggregate may be any aggregate typically used in inorganic binder compositions, particularly cement-based binder compositions. Typical aggregates include, for example, rock, crushed stone, gravel, slag, sand, especially quartz sand, river sand, and / or crushed sand, recycled concrete, glass, foamed glass, pumice, perlite, vermiculite, and / or fine aggregates, such as limestone powder, dolomite powder, aluminum oxide powder, silica fume, quartz powder, and / or steelmaking slag powder. Aggregates useful in the present invention can have any shape and size typically obtained from such aggregates.

[0068] The particle size of the aggregate depends on the application and may be, for example, within the range of 0.1 μm to 32 mm. Preferably, aggregates with different particle sizes are mixed to optimize the properties of the inorganic binder composition. Aggregates with different chemical compositions can also be used.

[0069] According to the embodiment, aggregate having a particle size of 8 mm or less, more preferably 5 mm or less, even more preferably 3.5 mm or less, most preferably 2.2 mm or less, particularly 1.2 mm or less, or 1.0 mm or less is used in the inorganic binder composition of the present invention.

[0070] The maximum particle size is limited, in particular, by the planned layer thickness during use of the inorganic binder composition mixed with water. For example, the maximum particle size of the aggregate should be the same as the layer thickness during use.

[0071] According to embodiments, the inorganic binder composition of the present invention comprises, based on the total dry weight of the inorganic binder composition, up to 85% by weight, preferably 30-80% by weight, more preferably 40-70% by weight of aggregate, preferably sand, particularly quartz sand, and / or limestone.

[0072] According to the embodiment, sand having a particle size of less than 1 mm, preferably less than 0.8 mm, is used in the inorganic binder composition of the present invention.

[0073] An inorganic binder composition containing this type of aggregate, when mixed with water, can be easily transported, readily mixed with additives, and yields a highly uniform inorganic binder matrix and surface after use. Furthermore, this helps to obtain a uniform distribution of carbon nanotubes and carbonaceous particles.

[0074] The inorganic binder composition may further advantageously contain additives common in the mortar and / or concrete industry, such as dispersants, plasticizers, fluidizers, accelerators, retarders, rheological modifiers, thickeners, anti-settling agents, pigments, rust inhibitors, fibers, strength enhancers, waterproofing agents, alkali-aggregate reaction inhibitors, chromate reducers, and / or antimicrobial agents. It may be advantageous to use two or more of the above additives in a single inorganic binder composition.

[0075] In particular, the ratio of the additive is 0 to 10% by weight, preferably 0.1 to 7% by weight, and more preferably 0.2 to 5% by weight, based on the total dry weight of the inorganic binder composition.

[0076] According to embodiments, the inorganic binder composition of the present invention comprises a dispersant and / or fluidizing agent selected from the group consisting of lignosulfonate, sulfonated vinyl copolymer, polynaphthalene sulfonate, sulfonated melamine formaldehyde condensate, polyethylene oxide phosphonate, polycarboxylate ether (PCE), or mixtures thereof. Preferably, the inorganic binder composition of the present invention comprises PCE.

[0077] Such additives are particularly useful for obtaining a uniform distribution of components in inorganic binder compositions, especially carbon nanotubes and carbonaceous particles.

[0078] According to the embodiment, the PCE comprises free carboxylic acid groups, i.e., unneutralized carboxylic acid groups, and / or carboxylic acid groups in the form of alkali and / or alkaline earth metal circles. A PCE without further anionic groups other than carboxylic acid groups is preferred. A PCE consisting of side chains of at least 80 mol%, preferably at least 90 mol%, and particularly preferably 100 mol%, of ethylene glycol units is even more preferred. Preferably, the side chains have an average molecular weight Mw in the range of 500 to 10,000 g / mol, preferably 800 to 8,000 g / mol, and particularly preferably 1,000 to 5,000 g / mol. Side chains of different molecular weights may also be present in the PCE. Most preferably, the PCE is composed of (meth)acrylic acid and methyl polyalkylene glycol (meth)acrylate. The PCE has an average molecular weight M of preferably 8,000 to 200,000 g / mol, particularly 10,000 to 100,000 g / mol, relative to a PEG standard. w It has.

[0079] According to a particularly preferred embodiment, the inorganic binder composition of the present invention: a) with at least one inorganic binder in an amount of 10-65% by weight, preferably 12-55% by weight, and especially 15-50% by weight; b) Carbon nanotubes in an amount of 0.2 to 1000 ppm, preferably 1 to 900 ppm, more preferably 10 to 500 ppm, and especially 100 to 400 ppm; c) 0.5-10% by weight, especially 2-6% by weight, for example 3-5% by weight or 3.5-4.5% by weight of carbonaceous particles; d) Aggregate in an amount of 0-85% by weight, preferably 30-80% by weight, more preferably 40-70% by weight, preferably sand and / or gravel; e) 0 to 10% by weight, preferably 0.1 to 7% by weight, more preferably 0.2 to 5% by weight, one or more additives selected from the group consisting of dispersants, plasticizers, fluidizers, accelerators, retarders, rheological modifiers, thickeners, anti-settling agents, pigments, rust inhibitors, fibers, strength enhancers, waterproofing agents, alkali-aggregate reaction inhibitors, chromate reducing agents, and / or antibacterial agents, f) Mixing water, in some cases, particularly mixing water in which the ratio of water to inorganic binder is 0.25 to 0.8; The values ​​include the total dry weight of the inorganic binder composition, excluding the mixing water.

[0080] According to the embodiment, the inorganic binder composition: a) with at least one inorganic binder in an amount of 10-65% by weight, preferably 12-55% by weight, and especially 15-50% by weight; b) Carbon nanotubes in an amount of 0.2 to 1000 ppm, preferably 1 to 900 ppm, more preferably 10 to 500 ppm, and especially 100 to 400 ppm; c) 0.5-10% by weight, especially 2-6% by weight, for example, 3-5% or 3.5-4.5% by weight of carbon black; d) Aggregate in an amount of 0-85% by weight, preferably 30-80% by weight, more preferably 40-70% by weight, preferably sand and / or gravel; e) 0 to 10% by weight, preferably 0.1 to 7% by weight, more preferably 0.2 to 5% by weight, one or more additives selected from the group consisting of dispersants, plasticizers, fluidizers, accelerators, retarders, rheological modifiers, thickeners, anti-settling agents, pigments, rust inhibitors, fibers, strength enhancers, waterproofing agents, alkali-aggregate reaction inhibitors, chromate reducing agents, and / or antibacterial agents, f) Depending on the case, water, particularly water in which the ratio of water to the inorganic binder is 0.25 to 0.8; These include the total dry weight of the inorganic binder composition, with each value based on that weight.

[0081] In particular, the inorganic binder composition is a mortar, concrete, screed, sealant, and / or grout composition.

[0082] In particular, the inorganic binder composition is a screed composition, especially a self-leveling screed composition. Such compositions can be used directly, for example, in the manufacture of antistatic flooring and / or flooring with integrated heating capability.

[0083] In particular, the inorganic binder composition is a dry composition. Within the scope of this context, "dry composition" means an inorganic binder composition having a water content of 0.5% by weight or less based on the total weight of the inorganic binder composition. In this case, no mixing water is present.

[0084] In another embodiment, the inorganic binder composition is a treatable composition containing mixed water. In this case, in particular, the ratio of water to inorganic binder in the inorganic binder composition is 0.25 to 0.7.

[0085] A further aspect of the present invention is a method for manufacturing a cured article: (i) A step of mixing the inorganic binder composition of the present invention with water, (ii) The step of arranging the mixture obtained in step (i) into any desired shape (iii) A step of curing the arranged mixture obtained in step (ii), Includes.

[0086] The ratio of water to inorganic binder in the inorganic binder composition in step (i) is preferably selected within the range of 0.25 to 0.7.

[0087] In particular, in step (i), the nanotubes are mixed with another component of the inorganic binder composition in the form of the aforementioned dispersion and / or water.

[0088] In particular, during step (iii), an electric current is passed through the placed mixture in order to resistively heat the mixture during the curing process. This accelerates the curing process.

[0089] This allows, for example, a voltage of 1 to 100V, especially 20 to 60V, especially 30 to 50V, to be applied between opposite sides of the arranged mixture, particularly via electrodes, especially graphite electrodes, in order to pass an electric current through the arranged mixture.

[0090] A further aspect of the present invention relates to a cured article comprising the aforementioned cured inorganic binder composition and / or obtained by curing the aforementioned inorganic binder composition with water. Thereafter, carbonaceous particles and carbon nanotubes preferably form a continuous percolation network as described above.

[0091] In particular, the hardened articles described above are part of, or form part of, runways, roads, sidewalks, stairs, floors, walls, ceilings, roofs, or supporting structures of buildings or infrastructure structures.

[0092] In particular, the cured articles are part of, or form part of, floors in a building, especially screeds. For example, the molded articles are part of, or form part of, antistatic floors and / or electrically heated floors.

[0093] In another preferred embodiment, the cured article is part of, or forms part of, an electrical component, in particular an electric capacitor, in particular a supercapacitor. A supercapacitor, also called an ultracapacitor, is a high-capacitance capacitor that has a much higher capacitance than other capacitors but has a lower voltage limit. This fills the gap between electrolytic capacitors and batteries.

[0094] For example, the cured material is a capacitor electrode.

[0095] The above-mentioned electrical components or capacitors can be used, for example, for energy storage. Accordingly, another aspect of the present invention relates to an object selected from runways, roads, sidewalks, stairs, floors, walls, ceilings, roofs, or supporting structures of buildings or infrastructure structures, comprising or comprising the aforementioned cured inorganic binder composition or the aforementioned cured article.

[0096] Furthermore, the present invention relates to a capacitor, particularly a supercapacitor, that includes or comprises at least one capacitor electrode containing the cured articles described herein.

[0097] In particular, the capacitor includes or comprises the cured articles described herein and includes at least two capacitor electrodes separated by a dielectric medium. The dielectric medium is, in particular, a porous medium that is permeable to electrolyte species, such as paper and / or cement.

[0098] However, the capacitor may also be based on a capacitor electrode comprising or consisting of the cured articles described herein, and at least one further capacitor electrode of a different material, such as metal or earth.

[0099] In particular, the capacitor may be part of a building or infrastructure structure.

[0100] In particular, the above-mentioned cured article or object is 10 at 20°C -6 From Ωm to 10 4 Less than Ωm, especially 10 -4 Ωm~10 3 It has an electrical resistivity of Ωm. In particular, the cured article has an electrical resistivity of less than 1,000 Ωm, especially less than 500 Ωm, and especially less than 100 Ωm. The electrical resistivity is measured especially after 28 days of curing.

[0101] When measuring electrical resistivity, for example, the sample can be placed between conductive electrodes, particularly graphite electrodes, connected to a DC power supply. By applying a voltage and using Ohm's law and the geometric dimensions of the sample, the electrical resistivity (= the reciprocal of conductivity) can be determined.

[0102] Furthermore, the present invention relates to a method for heating a cured article or object, wherein an electric current is passed through the cured article or object, and the cured article or object is heated by resistance heating.

[0103] Therefore, preferably, a voltage of 1 to 100V, particularly 20 to 60V, and particularly 30 to 50V, is applied, for example, between opposite sides of the cured article or object, particularly via electrodes, particularly graphite electrodes, so that a current flows through the cured article or object.

[0104] A further aspect of the present invention relates to the use of the aforementioned inorganic binder composition or cured article as an antistatic flooring for structural monitoring, electromagnetic shielding, electrostatic discharge protection, corrosion prevention of steel-reinforced concrete structures, as a heat source for buildings or infrastructure structures, as an element of an electric capacitor, particularly a supercapacitor, particularly as a capacitor electrode, and / or for the storage of electrical energy.

[0105] Furthermore, the present invention relates to the use of carbon nanotubes and carbonaceous particles for reducing the electrical resistivity of an inorganic binder composition, wherein the carbonaceous particles are chemically and / or physically different from carbon nanotubes.

[0106] The aforementioned special features and embodiments relating to the inorganic binder composition of the present invention are also advantageously realized in the aforementioned cured articles, objects, methods, and uses.

[0107] Further advantageous embodiments of the present invention are evident from representative embodiments. These examples are not intended to limit the scope of the invention in any way. [Brief explanation of the drawing]

[0108] [Figure 1] This shows a comparison of the temperature changes between the inorganic binder composition of the present invention and two reference compositions.

[0109] Typical Embodiments Mortar mixture To produce the dry mortar mixture M1 according to the present invention, 490 g of cement (CEM I 52.5), 1,350 g of quartz sand (CEN), and 1 g of fluidizer (polycarboxylate ether) were mixed with 3.6 wt% of carbon black (Vulcan XC72R; available from Cabot Corporation; average particle size: 50 nm) and 400 ppm of single-walled carbon nanotubes (used in the form of an aqueous dispersion of single-walled carbon nanotubes (OCSiAL Tuball® Coat_E H2O 0.4% (sodium dodecylbenzenesulfonate); available from OCSiAL Europe; average outer diameter: 1.6 nm; average length > 5 μm; G / D ratio > 90). The amount of nanotubes added was 400 ppm. All wt% and ppm values ​​are based on the total weight of the total dry components of the inorganic binder composition.

[0110] As the first reference mortar mixture R1, the same type of cement, quartz sand, and plasticizer used in mixture M1 were mixed with 4.5 wt% carbon black (Vulcan XC72R). In this case, carbon nanotubes were not added. However, the ratios of cement, sand, and plasticizer were maintained to be the same as those of mixture M1.

[0111] As a second reference mortar mixture R2, the same type of cement, quartz sand, and superplasticizer used in mixture M1 were mixed with 900 ppm of single-walled carbon nanotubes (used in the form of an aqueous dispersion of single-walled carbon nanotubes (OCSiAL Tuball® Coat_E H2O 0.4% (sodium dodecylbenzenesulfonate))). The amount of nanotubes added was 900 ppm. In this case, no carbon black was added. Again, the ratios of cement, sand, and superplasticizer were maintained to be the same as in mixture M1.

[0112] A mortar mixture was mixed with mixing water (w / c=0.6) in a Hobart mixer, and hardened in the form of a cubic specimen (4×4×16cm) to obtain a hardened mortar sample.

[0113] Thermoelectric testing A hardened mortar sample was placed between conductive graphite electrodes connected to a DC power supply. Next, a voltage of 40V was applied to the electrodes to resistively heat the sample. The temporary temperature change of the sample was measured using a thermographic camera.

[0114] Figure 1 shows the temperature changes of the three samples. Clearly, the sample based on mortar composition M1 of the present invention reached a temperature of 100°C within approximately 10 minutes. In contrast, the reference samples based on compositions R1 and R2 only reached a temperature of approximately 60-70°C within 36 minutes.

[0115] Clearly, the carbon black and carbon nanotubes in the mortar composition M1 of the present invention interact synergistically compared to another sample containing only one of the two carbon-based materials.

[0116] Therefore, using the mortar composition of the present invention, conductive cured articles can be manufactured that can be heated in a very efficient manner at a fairly fast heating rate. Furthermore, the above mortar composition can be easily adjusted to meet specific processing requirements and desired lipids by adjusting the formulation of the inorganic binder composition.

[0117] Those skilled in the art will recognize that the present invention can be implemented in other specific forms without departing from the intent or essential features of the invention. Accordingly, the embodiments disclosed herein are considered to be explanatory and not restrictive in all respects.

Claims

1. An inorganic binder composition, particularly a conductive inorganic binder composition, comprising at least one inorganic binder, a carbon nanotube, and carbonaceous particles, wherein the carbonaceous particles are chemically and / or physically different from the carbon nanotube.

2. The inorganic binder composition according to claim 1, wherein the carbon nanotube is a single-walled carbon nanotube.

3. The inorganic binder composition according to claim 1 or 2, wherein the carbon nanotubes have an average outer diameter of about 0.4 to 25 nm, particularly 0.6 to 10 nm, for example 1 to 5 nm, particularly 1.2 to 2.0 nm; and the carbon nanotubes have an average length of at least 0.5 μm, particularly at least 1 μm, particularly at least 4 μm, particularly at least 5 μm.

4. The inorganic binder composition according to any one of claims 1 to 3, wherein the carbonaceous particles are selected from carbon black, graphene flakes, multi-walled carbon nanotubes, coke particles, and / or activated carbon.

5. The inorganic binder composition according to any one of claims 1 to 4, wherein the carbonaceous particles are selected from carbon black.

6. The inorganic binder composition according to any one of claims 1 to 5, wherein the carbonaceous particles have an average particle size of 10 to 500 nm, particularly 20 to 300 nm, particularly 25 to 100 nm, particularly 30 to 70 nm, or 40 to 60 nm.

7. The inorganic binder composition according to any one of claims 1 to 6, wherein the carbonaceous particles are selected from carbon black having a particle size of 25 to 100 nm, and the carbon nanotubes are single-walled carbon nanotubes having an average length of at least 5 μm and an average diameter of about 1.2 to 2.0 nm.

8. The inorganic binder composition according to any one of claims 1 to 7, wherein the ratio of carbon nanotubes, particularly single-walled carbon nanotubes, based on the total weight of all dry components of the inorganic binder composition is 0.2 to 1000 ppm, preferably 1 to 900 ppm, more preferably 10 to 500 ppm, particularly 100 to 400 ppm; and the ratio of carbonaceous particles, particularly carbon black, based on the total weight of all dry components of the inorganic binder composition is 0.5 to 10% by weight, particularly 2 to 6% by weight, for example 3 to 5% by weight or 3.5 to 4.5% by weight.

9. The ratio of carbonaceous particles to carbon nanotubes is selected such that a continuous percolation network of carbonaceous particles and carbon nanotubes exists. The inorganic binder composition according to any one of claims 1 to 8.

10. The inorganic binder composition according to any one of claims 1 to 9, wherein the at least one inorganic binder is selected from cement, hydraulic lime, fly ash, slag, silica fume, and / or gypsum.

11. a) 10 to 65% by weight, preferably 12 to 55% by weight, and particularly 15 to 50% by weight of the at least one inorganic binder; b) With the carbon nanotubes in a concentration of 0.2 to 1000 ppm, preferably 1 to 900 ppm, more preferably 10 to 500 ppm, and particularly 100 to 400 ppm; c) 0.5 to 10% by weight, particularly 2 to 6% by weight, for example 3 to 5% by weight or 3.5 to 4.5% by weight of the carbonaceous particles; d) Aggregate in an amount of 0 to 85% by weight, preferably 30 to 80% by weight, more preferably 40 to 70% by weight, preferably sand and / or gravel; e) 0 to 10% by weight, preferably 0.1 to 7% by weight, more preferably 0.2 to 5% by weight, one or more additives selected from the group consisting of dispersants, plasticizers, fluidizers, accelerators, retarders, rheological modifiers, thickeners, anti-settling agents, pigments, rust inhibitors, fibers, strength enhancers, waterproofing agents, alkali-aggregate reaction inhibitors, chromate reducing agents, and / or antibacterial agents, f) Depending on the case, water, particularly water in which the ratio of water to the inorganic binder is 0.25 to 0.8; The inorganic binder composition according to any one of claims 1 to 10, comprising, each based on the total dry weight of the inorganic binder composition.

12. A cured article comprising a cured inorganic binder composition according to any one of claims 1 to 11, and / or a cured article that can be obtained by adding water to the inorganic binder composition according to any one of claims 1 to 11 and curing it.

13. An object selected from runways, roads, sidewalks, stairs, floors, walls, ceilings, roofs, or supporting structures for buildings or infrastructure structures, comprising or including a cured inorganic binder composition according to any one of claims 1 to 11 or a cured article according to claim 12.

14. A method for heating a cured article according to claim 12, or an object according to claim 13, wherein an electric current is passed through the cured article or the object, and in particular the cured article or the object is heated by resistance heating.

15. Use of the inorganic binder composition according to any one of claims 1 to 11, or the cured article according to claim 12, for use in structural monitoring, electromagnetic shielding, electrostatic discharge protection, corrosion prevention of steel-reinforced concrete structures, as antistatic flooring, as a heat-generating element for buildings or infrastructure structures, as an element of an electric capacitor, especially a supercapacitor, especially as a capacitor electrode, and / or for the storage of electrical energy.

Images