Thermal insulation plaster

Abstract

Thermal insulation plaster as a heat-insulating base coat for facades, comprising a dry mortar made of at least one binder, a mixture of lightweight aggregates and additives to improve the material properties, characterized in that the mixture of lightweight aggregates comprises either aluminosilicates, preferably of different grain sizes, or expanded perlite, aerogel granules and a synthetically produced lightweight aggregate with a mineral composition from the tobermorite group.

Description

[0001] The present invention relates to a thermal insulation plaster as a heat-insulating base coat for facades, comprising a dry mortar made of at least one binder, a mixture of lightweight aggregates and additives to improve the material properties.

[0002] Insulating plasters serve as a base for topcoats. Thanks to their low density and strength, insulating plasters offer excellent vapor permeability (diffusion) and are considered lightweight plasters. However, since the plaster surface must be water-repellent and impact-resistant, insulating plaster is unsuitable as a topcoat.

[0003] The low dry density is achieved by using mineral and / or organic lightweight aggregates with an open-pore structure instead of the usual sands. These properties of the lightweight plasters significantly reduce the risk of cracking that could occur later or during application, as the material exhibits high elasticity and elongation to compensate for static and thermal stresses and is specifically tailored to the masonry substrate. A thermal insulation plaster must have a low thermal conductivity of ≤ 0.2 W / (m·K) to effectively contribute to the thermal insulation of a building.

[0004] Thermal insulation plasters must possess the following key properties. First, they must have low thermal conductivity, meaning they reduce heat flow through the wall and thus contribute to energy savings. They are also lighter than conventional plasters, which reduces the load on the building structure and facilitates application. Thermal conductivity can be further reduced by incorporating porous structures into the plaster. High porosity contributes to thermal insulation because the trapped air pores act as an insulating layer, improving the plaster's insulating performance. Thermal insulation plasters are also vapor-permeable, allowing moisture to escape from the masonry. This helps prevent moisture problems and mold growth.Thanks to their high elasticity and extensibility, thermal insulation plasters can compensate for movements in the substrate and minimize the risk of cracking. Furthermore, thermal insulation plasters are designed to be resistant to various weather conditions such as rain, frost, and UV radiation. They are also generally non-combustible or flame-retardant, which improves the building's fire safety.

[0005] Against this background, the invention is based on the objective of providing a crack-resistant thermal insulation plaster which, on the one hand, has a particularly low thermal conductivity and, on the other hand, is weather-resistant.

[0006] The problem is solved by a thermal insulation plaster according to the features of independent claim 1. Meaningful embodiments of such a thermal insulation plaster can be found in the subsequent dependent claims.

[0007] The invention describes a thermal insulation plaster intended as a heat-insulating base coat for facades, comprising a dry mortar made of at least one binder, a mixture of lightweight aggregates, and additives for improving the material properties. According to the invention, the thermal insulation plaster is characterized in that the mixture of lightweight aggregates comprises either aluminosilicates, preferably of different grain sizes, or expanded perlite, aerogel granules, and a synthetically produced lightweight aggregate with a mineral composition from the tobermorite group. This makes the thermal insulation plaster a high-performance thermal insulation plaster.

[0008] The thermal insulation plaster according to the invention, which comprises a dry mortar, exhibits both the properties of a conventional plaster and additional thermal insulation properties. This type of plaster is supplied in the form of dry mixes that only need to be mixed with water on the construction site. The thermal insulation plaster has low thermal conductivity, which means that it reduces heat flow through the wall and thus contributes to energy savings. Furthermore, due to the addition of lightweight aggregates, this thermal insulation plaster is lighter than conventional plasters, which reduces the load on the building structure and facilitates application. The lightweight aggregates can include aerogel granules, which have a high porosity. This contributes to thermal insulation because the enclosed air pores act as an insulating layer.Expanded perlite and a mineral composition from the tobermorite group, for example tobermorite, can also be added to the thermal insulation plaster, thereby increasing the compressive strength of the plaster and reducing its weight. The thermal insulation plaster according to the invention also contains at least one binder, such as hydraulic lime, lime and / or cement, and additives to improve the material properties, such as air-entraining agents to increase porosity and improve thermal insulation, fibers to reinforce and increase crack resistance, water-repellent agents to improve water repellency, or retarders or accelerators to control the setting time.

[0009] At least one binder can be cement, which is added to the dry mortar at a weight of 30 to 50%. Cement is a widely used and effective binder in plaster mixes due to its numerous beneficial properties. Cement gives the plaster high compressive and tensile strength, which improves the structural integrity and durability of the plaster layer. This is particularly important for exterior plasters, which are exposed to mechanical stress and weathering. Cement-based plasters also adhere well to a variety of substrates, including masonry, concrete, and existing plaster layers. This ensures a stable and lasting bond between the plaster and the substrate. Cement is resistant to various weather conditions such as rain, frost, and UV radiation. This makes cement-based plasters resistant to environmental influences and contributes to the longevity of the plaster layer.Cement-based plasters are generally water-repellent, meaning they are less susceptible to moisture absorption and related damage such as mold growth and frost damage. Cement has a relatively fast setting time, which can shorten construction time and accelerate progress. This is particularly advantageous for projects with tight deadlines.

[0010] In one specific embodiment, at least one binder can be natural hydraulic lime, which is added to the dry mortar at a weight percentage of 10 to 40%. NHL lime can set both in air and underwater. This property makes it versatile, especially in damp environments or in applications requiring a certain degree of water resistance. Furthermore, NHL lime plasters are highly breathable, meaning they allow moisture to escape from the masonry. This helps prevent moisture buildup and related problems such as mold growth, which is particularly important in historic buildings. Compared to cement-based plasters, NHL lime is more flexible and can better accommodate movement in the substrate, reducing the risk of cracking. This property is especially advantageous in buildings subject to natural movement or temperature fluctuations.

[0011] Ideally, the thermal insulation plaster should have a thermal conductivity of less than 0.03 W / (m·K). Low thermal conductivity means the plaster allows less heat to pass through, resulting in better thermal insulation for the building. This contributes to energy savings by reducing heat loss in winter and heat absorption in summer. Consequently, the building's heating and cooling requirements are reduced, lowering both energy costs and CO2 emissions.

[0012] Polypropylene and / or polyethylene fibers can be added to the dry mortar to increase elasticity and reduce cracking, preferably at a weight percentage of 1%. In addition to increasing fire resistance, the fibers also enhance the tensile strength and crack resistance of the thermal insulation plaster.

[0013] Preferably, a surfactant can be added to the dry mortar to prevent cracking. These additives improve the plaster's flexibility, adhesion, and workability and help to balance stresses. Synthetic resins and polymers, among other substances, can be used. These are often employed to improve the plaster's flexibility and adhesion. They increase elasticity and help absorb stresses, thus reducing cracking. Air-entraining agents also reduce cracking by creating small, evenly distributed air pores in the plaster, which help to distribute stresses. Plasticizers can also be used, as they improve the plaster's workability and pliability, facilitating application and reducing the risk of cracking during drying and curing. Retarders and accelerators, water repellents, silica fume, or superplasticizers can also be used.

[0014] Specifically, the dry mortar can contain the additives hydroxyethylmethylcellulose, a modified starch, and sodium alkyl sulfates. These three additives have a beneficial effect on water retention and pore formation, thus improving the properties of the thermal insulation plaster.

[0015] At least one binder can be clay dust, which is added to the dry mortar at a weight percentage of 20 to 40%. Clay is used as a component of plaster mixes for several reasons. It is a traditional building material that has been used in many cultures for centuries and offers a number of advantages relating to both ecological and structural aspects.

[0016] In one embodiment, a binder can be natural hydraulic lime, wherein the natural hydraulic lime is added to the dry mortar with a weight fraction of 20 to 40 wt. %.

[0017] The thermal insulation plaster can have a thermal conductivity of less than 0.055 W / (m·K).

[0018] It is particularly advantageous for the aluminosilicates to have grain sizes between 1 and 300 µm, and for them to be added to the dry mortar at a weight fraction of 50 to 70 wt.%. Aluminosilicates offer a multitude of advantages that make them a valuable component in plaster mixes. Their use improves the mechanical strength, thermal insulation, fire resistance, moisture regulation, and workability of the plaster, while also being environmentally friendly and sustainable.

[0019] Finally, it may be provided that the dry mortar contains perlite at a weight fraction of 5 to 10 wt.%, aerogel granules with a size of 0.3 to 4 mm at a weight fraction of 5 to 15 wt.%, and a synthetically produced lightweight aggregate with a mineral composition from the tobermorit group at a weight fraction of 15 to 25 wt.%. Aerogel is a high-performance material used in these high-performance thermal insulation plasters to improve the energy efficiency, workability, and durability of the plasters.

[0020] The above describes a crack-resistant thermal insulation plaster which, on the one hand, has a particularly low thermal conductivity and, on the other hand, is weather-resistant.

Claims

[1] Thermal insulation plaster as a thermally insulating base coat for facades, comprising a dry mortar made of at least one binder, a mixture of lightweight aggregates and additives to improve the material properties, characterized by that the mixture of lightweight aggregates comprises either aluminosilicates, preferably of different grain sizes, or expanded perlite, aerogel granules and a synthetically produced lightweight aggregate with a mineral composition from the tobermorite group. [2] Thermal insulation plaster according to claim 1, characterized by that at least one binding agent is cement, which is added to the dry mortar in a weight proportion of 30 to 50 wt.%. [3] Thermal insulation plaster according to claim 2, characterized by that at least one binder is naturally hydraulic lime, which is added to the dry mortar in a proportion of 10 to 40% by weight. [4] Thermal insulation plaster according to claim 2 or 3, characterized bythat it has a thermal conductivity of less than 0.03 W / (m·K). [5] Thermal plaster according to one of the preceding claims, characterized by that polypropylene and / or polyethylene fibres are added to the dry mortar as an additive to increase elasticity and reduce cracking, preferably in a weight proportion of 1%. [6] Thermal plaster according to one of the preceding claims, characterized by that a surfactant is added to the dry mortar to prevent cracking. [7] Thermal plaster according to one of the preceding claims, characterized by that the dry mortar contains the additives hydroxyethylmethylcellulose, a modified starch, and sodium alkyl sulfates. [8] Thermal insulation plaster according to claim 1, characterized by that at least one binding agent is clay dust, wherein the clay dust is added to the dry mortar in a weight proportion of 20 to 40 wt.%. [9] Thermal insulation plaster according to claim 8, characterized by that at least one binder is natural hydraulic lime, the natural hydraulic lime being added to the dry mortar in a proportion of 20 to 40% by weight. [10] Thermal insulation plaster according to claim 8 or 9, characterized by that it has a thermal conductivity of less than 0.055 W / (m·K). [11] Thermal plaster according to claims 8 to 10, characterized by that the dry mortar contains the additives hydroxyethylmethylcellulose, a modified starch and sodium alkyl sulfates. [12] Thermal plaster according to one of the preceding claims, characterized by that the aluminosilicates have grain sizes between 1 and 300 µm, with the aluminosilicates being added to the dry mortar in a weight proportion of 50 to 70 wt.%. [13] Thermal plaster according to one of claims 1 to 11, characterized bythat expanded perlite with a weight proportion of 5 to 10 wt. %, aerogel granules with a size of 0.3 to 4 mm with a weight proportion of 5 to 15 wt. % and a synthetically produced lightweight aggregate with a mineral composition from the tobermorite group with a weight proportion of 15 to 25 wt. % are added to the dry mortar.