Polymeric spacer for insulating glazing with aerogel additive

Abstract

The present invention relates to a spacer (1) for an insulating glazing unit, which is made of a material which contains at least one polymeric base material, wherein at least one aerogel is added to the polymeric base material.

Description

[0001] The invention relates to a spacer for insulating glazing, a method for its manufacture and insulating glazing with the spacer.

[0002] In the windows and facades of buildings, insulating glass units are now almost exclusively used. Insulating glass units consist of at least two panes of glass, which are separated by a spacer at a defined distance from each other. The spacer is frame-like, usually rectangular, and is positioned around the perimeter of the glazing. This creates a space between the panes, which is typically filled with an inert gas. Compared to single glazing, insulating glass units significantly reduce heat flow between the interior space enclosed by the glazing and the outside environment. The spacer typically has a cavity filled with a desiccant to keep the space between the panes free of moisture.

[0003] Conventional spacers are made of a light metal (typically aluminum) or stainless steel. However, polymer spacers are also known, for example, from DE 27 52 542 C2 or DE 19 625 845 A1. Polymer spacers have lower thermal conductivity than metal spacers, thus significantly improving the thermal insulation of the glazing at the edges. Glass fibers are typically added to the polymer base material, increasing the stiffness and stability of the spacer and limiting the coefficient of thermal expansion. While glass fibers generally have a negative effect on thermal conductivity, this can be minimized by appropriate orientation of the glass fibers.

[0004] As a general rule, experts always strive to minimize heat flow through insulating glass. Therefore, there remains a need for spacers with reduced thermal conductivity.

[0005] The present invention is based on the objective of providing such an improved polymeric spacer which has a reduced thermal conductivity.

[0006] The object of the invention is achieved according to the invention by a polymeric spacer for insulating glazing according to claim 1. Preferred embodiments are described in the dependent claims.

[0007] The spacer according to the invention is made of a material which contains at least one polymeric base material. It is characterized in that at least one aerogel is added to the polymeric base material.

[0008] Aerogels are well known to those skilled in the art. They are highly porous solids, known for their very low thermal conductivity and heat-insulating properties. The addition of aerogel reduces the thermal conductivity of the spacer material compared to that of the polymeric base material. This is the major advantage of the present invention.

[0009] The spacer is fundamentally based on a polymeric base material. This determines the spacer's basic properties, which are influenced by additives (according to the invention, at least the aerogel, preferably also glass fibers, and optionally also colorants, stabilizers, and similar additives). The proportion of the polymeric base material in the spacer material is preferably at least 40 wt.%, particularly preferably at least 50 wt.%, and most preferably at least 60 wt.%. The proportion of the polymeric base material can, for example, range from 40 wt.% to 95 wt.%, or from 50 wt.% to 95 wt.%, or from 60 wt.% to 90 wt.%, or from 60 wt.% to 70 wt.%.

[0010] The spacer material contains at least one aerogel additive in addition to the polymeric base material. The aerogel content is preferably at least 5 wt.%, more preferably at least 10 wt.%. This advantageously reduces the material's heat transfer capacity. Generally, a higher aerogel content is beneficial for thermal conductivity. However, the aerogel content should not be too high, so that there is room for further additives (especially glass fibers) without significantly reducing the proportion of the polymeric base material. In an advantageous embodiment, the aerogel content is between 10 wt.% and 20 wt.%, more preferably between 10 wt.% and 15 wt.%.

[0011] Typically, polymer spacers contain added glass fibers. The glass fiber content primarily improves the mechanical properties of the spacer, particularly increasing its stiffness and limiting thermal expansion. The spacer according to the invention also preferably contains glass fibers. In an advantageous embodiment, glass fibers are added to the spacer material in addition to the aerogel. The glass fiber content is preferably at least 15 wt.%, particularly preferably at least 20 wt.%. Here, too, the glass fiber content should not be too high in order to leave room for the aerogel additive and not to reduce the proportion of the polymer base material too much. In a particularly advantageous embodiment, the glass fiber content is from 20 wt.% to 30 wt.%, preferably from 20 wt.% to 25 wt.%.

[0012] The spacer material may contain other additives, as is common in industrially processed plastics. These include, in particular, stabilizers, such as UV stabilizers or chemical stabilizers, color additives, and / or processing aids. The proportion of such other additives is preferably at most 5% by weight, more preferably at most 2% by weight, for example, from 0.1% to 2% by weight or from 0.5% to 2% by weight.

[0013] In a particularly advantageous embodiment, the material of the spacer contains (or consists of): at least 5 wt.% of the aerogel, preferably at least 10 wt.%, particularly preferably from 10 wt.% to 20 wt.%, most preferably from 10 wt.% to 15 wt.%, at least 15 wt.% of glass fibers, preferably at least 20 wt.%, particularly preferably from 20 wt.% to 30 wt.%, most preferably from 20 wt.% to 25 wt.%, at most 5 wt.% of other additives, in particular containing stabilizers (such as UV stabilizers), color additives, curing agents and / or processing aids, preferably at most 2 wt.%, particularly preferably from 0.1 wt.% to 2 wt.%, for example from 0.5 wt.% to 2 wt.%.

[0014] The remainder is formed by the polymeric base material, so that the sum of the components is 100 wt.%.

[0015] In a particularly advantageous embodiment, the material of the spacer contains (or consists of): at least 5 wt.% of the aerogel, at least 15 wt.% of glass fibers, at most 5 wt.% of said other additives, preferably at least 10 wt.% of the aerogel, at least 20 wt.% of glass fibers, at most 2 wt.% of other additives, particularly preferably from 10 wt.% to 20 wt.% of the aerogel, from 20 wt.% to 30 wt.% of glass fibers, at most 2 wt.% (for example from 0.1 wt.% to 2 wt.%) of said other additives, most preferably from 10 wt.% to 15 wt.% of the aerogel, from 20 wt.% to 25 wt.% of glass fibers, at most 2 wt.% (for example from 0.1 wt.% to 2 wt.% or from 0.5 wt.% to 2 wt.%) of said other additives.

[0016] The remainder is formed by the polymeric base material, so that the sum of the components is 100 wt.%.

[0017] The polymer base material is not fundamentally limited to specific polymers. Preferably, all polymers commonly used for conventional polymer spacers can be employed. Amorphous thermoplastics are particularly advantageous from a thermal perspective and are therefore preferred.

[0018] In an advantageous embodiment, the polymeric base material is polypropylene (PP), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylonitrile (ASA), acrylonitrile butadiene styrene polycarbonate (ABS / PC), styrene acrylonitrile (SAN), polyethylene terephthalate polycarbonate (PET / PC), polybutylene terephthalate polycarbonate (PBT / PC), polyethylene (PE), polycarbonate (PC), polystyrene (PS), polybutadiene, polynitrile, polyester, polyurethane, polymethyl methacrylate, polyacrylate, polyamide, polyethylene terephthalate (PET), glycol-modified PET (PETG), polybutylene terephthalate (PBT), or copolymers, derivatives, or mixtures thereof. Derivatives are understood to be, in particular, polymers with the basic chain of the aforementioned polymers, which bear additional substituents.

[0019] Preferred materials include polypropylene (PP), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylonitrile (ASA), acrylonitrile butadiene styrene polycarbonate (ABS / PC), styrene acrylonitrile (SAN), glycol-modified PET (PETG), polyethylene terephthalate polycarbonate (PET / PC), polybutylene terephthalate polycarbonate (PBT / PC) or copolymers or derivatives or mixtures thereof.

[0020] Contrary to what the name might suggest, aerogels are not gels, but highly porous solids. The name derives from the fact that aerogels are typically produced from gels, with the liquid component of the gel being replaced by a gas without the gel structure collapsing, for example, through supercritical drying or freeze-drying. Structurally, aerogels consist of a branching network of particle chains (dendritic structure) with numerous spaces (pores), particularly in the form of open pores. The particle chains have contact points with each other, so the aerogel can be considered a stable, sponge-like network. The particle chains themselves often result from the fusion of, for example, spherical particles. A very high volume fraction of aerogels consists of pores, especially open pores. Therefore, aerogels have a very low density. Aerogels can be produced, for example, using sol-gel processes.

[0021] Deposits may be present in the pores, for example, to influence the mechanical, thermal, or optical properties of the aerogel layer. The pores are typically air-filled, apart from any deposits.

[0022] For the purposes of this invention, porosity is defined as the proportion of the pore volume to the total volume of the aerogel. The aerogel preferably has a porosity of 50% to 99.98%, more preferably 80% to 99%, and most preferably 85% to 98%. The porosity can be determined by gas sorption measurement using nitrogen as the sample gas, and in particular using carbon dioxide (CO₂) as the sample gas at a temperature of 273 K.

[0023] The pore size of the aerogel is preferably from 1 nm to 50 nm, particularly preferably from 10 nm to 40 nm. This refers specifically to the diameter of the typically approximately spherical pores. The pore size can also be determined using the aforementioned gas sorption measurement.

[0024] The density of the aerogel is preferably from 0.16 mg / cm³ to 500 mg / cm³, and particularly preferably from 10 mg / cm³ to 300 mg / cm³. This refers to the bulk density based on the volume including the pore spaces, whereby the air in the pores is not included in the mass calculation.

[0025] The particles that make up the network of particle chains typically have a size of 1 nm to 10 nm.

[0026] Aerogels can be formed from various materials (material of the particle chains). The aerogel is preferably composed of silicate, a polymer, carbon, cellulose, or a metal oxide. In principle, all polymers and metal oxides are suitable. Examples include polyimide for a polymer and aluminum oxide, titanium oxide, zirconium oxide (all transparent and white or bluish), iron oxide (opaque, red, or yellow), chromium oxide (opaque, green, or blue), and vanadium oxide (opaque, olive green) for metal oxides. Strictly speaking, silicate aerosols do not have the chemical composition of a silicate, but rather something like SiO(OH)₂y(OR)₂z, where R is an organic residue and the parameters y and z depend on the manufacturing process. Nevertheless, they are generally referred to as such, and the term silicate is used accordingly within the scope of the present invention. In English, the term "silica aerogel" (i.e., SiO₂ aerogel) is also common.For the present invention, silicate aerogels, polymer aerogels, and cellulose aerogels are particularly preferred. These aerogels are well-researched and already commercially available in large numbers. According to the invention, at least one aerogel is added to the spacer material; however, several different aerogels can also be added.

[0027] In a particularly advantageous embodiment, the spacer material is foamed. During manufacturing, a foaming agent is typically added to the material, which decomposes (for example, thermally) and releases a gas, typically carbon dioxide (CO₂) or nitrogen (N₂). This creates pores in the material. These pores are, in particular, closed pores, so that the gas remains permanently trapped within them. Since the gas, especially CO₂ or N₂, has a lower thermal conductivity than the polymeric material, the thermal conductivity of the spacer is further reduced by these gas-filled pores.

[0028] Due to the foaming process, the spacer material contains gas inclusions with a volume fraction of preferably no more than 25 vol.%, for example from 5 vol.% to 25 vol.%, particularly preferably from 10 vol.% to 15 vol.%. This allows the thermal conductivity to be significantly reduced without the material being mechanically weakened to a critical degree.

[0029] The spacer is not limited to a specific shape. Here, we are referring to the cross-sectional shape. Typically, the spacer is designed as a hollow profile, meaning it has a cavity or hollow chamber surrounded by polymer walls. This cavity is specifically designed and suitable for holding a desiccant when installed, in order to keep the space between the panes of the insulating glass unit free of moisture. In principle, however, the spacer can also be solid, without an internal cavity.

[0030] In any case, the spacer has two opposing side surfaces, which are typically aligned parallel to each other. These side surfaces are designed to face the glass panes of the insulating glass unit and to be attached to them. The spacer also has an inner surface and an outer surface, the inner surface being designed to face the space between the panes and the outer surface being designed to face the external environment of the insulating glass unit.

[0031] The width of the spacer, according to the invention, is the distance between the side surfaces. The height of the spacer, according to the invention, is the distance between the inner and outer surfaces. The width is preferably from 5 mm to 35 mm, more preferably from 5 mm to 33 mm, for example from 10 mm to 20 mm. The height is preferably from 3 mm to 20 mm, more preferably from 5 mm to 10 mm, and most preferably from 5 mm to 8 mm.

[0032] In its hollow profile configuration, the spacer typically has two side walls designed to be attached to the glass panes of the insulating glass unit. These side walls are preferably aligned parallel to each other. At least the outer surface of the side walls (side faces), which in the installed position face the glass panes of the insulating glass unit, is typically flat. Preferably, the entire side walls are flat. This means that the inner surface, which faces the cavity, is also flat and the side wall has a constant material thickness.

[0033] The two side walls are connected by an inner wall and an outer wall. The side walls, the inner wall, and the outer wall enclose the aforementioned cavity. The inner wall is designed to face the space between the glass panes in the insulating glass unit. In an advantageous embodiment, the inner wall is provided with perforations to ensure the effect of a desiccant in the cavity on the space between the panes. The outer wall is opposite the inner wall, thus facing away from the aforementioned space, and is designed to face the external environment of the insulating glass unit.

[0034] The spacer preferably has a wall thickness of 0.5 mm to 2 mm, and particularly preferably of 0.8 mm to 1.5 mm. Wall thickness refers to the thickness of the walls, i.e., the side walls, the outer wall, and the inner wall; it can also be described as material thickness.

[0035] The ends of the spacers are open. This applies to the straight spacer sections in their initial state. For use in insulating glass units, the spacer is formed into a frame-like, particularly rectangular, shape in which there are no longer any open ends. This is done either by bending or by joining. When bending, the spacer is cut to the required length (whereby several straight spacer sections can first be joined together to form an extended workpiece using a longitudinal connector that is inserted into the opposing ends of both sections to be joined), bent into the frame-like shape so that the two ends point towards each other, and the two ends are then joined together, for example, by a longitudinal connector or a corner connector that is inserted into the opposing ends.During assembly, spacer sections are cut to size, forming the four sides of the frame, and these are then connected to each other via corner connectors that are inserted into the ends of adjacent sections.

[0036] In a preferred embodiment, the inner wall is also planar. The outer wall can also be entirely planar. Typically, the outer wall and the inner wall form a 90° angle with the side walls to which they are connected. In this case, the spacer has a rectangular profile. However, the outer wall is often composed of several planar sections: the middle section is parallel to the inner wall, and the sections adjacent to the side walls form an angle greater than 90° with the middle section on one side and the associated side wall on the other, in particular 120° to 150°, ideally 135°. The angled construction of the outer wall is particularly advantageous for applying a sealant in the edge area of ​​the finished insulating glass unit and has therefore proven especially effective. Each wall is connected at its ends to the respective ends of the two adjacent walls.

[0037] The outer surface and optionally also the side surfaces of the spacer are preferably provided with an insulating film that acts as a diffusion barrier. In the configuration of a hollow profile, the insulating film is arranged on the outer wall (more precisely, on the surface facing away from the cavity (outer surface) of the outer wall) and optionally on the side walls (more precisely, on the outer surfaces (side surfaces) of the side walls). The insulating film preferably comprises a polymeric film as a carrier film, for example, made of or based on polyethylene terephthalate, for example, with a thickness of 10 µm to 100 µm.Preferably, at least one metallic (in particular made of or based on iron, aluminum, silver, copper, gold, chromium, or alloys or mixtures thereof) and / or ceramic layer (in particular made of or based on silicon oxide and / or silicon nitride) is arranged on the carrier film, for example with a thickness of 1 nm to 1500 nm or of 10 nm to 1500 nm. The insulating film may contain further polymeric layers or films. The insulating film can, for example, be applied to the spacer sections by bonding or extruded together with the spacer sections.

[0038] The invention further comprises an insulating glass unit equipped with the spacer according to the invention. The insulating glass unit comprises at least two parallel glass panes connected to each other by a spacer according to the invention. The spacer is preferably arranged in an edge region between the glass panes, ideally circumferentially. The glass panes are preferably arranged in a plane parallel to each other. They preferably consist of soda-lime glass and preferably have a thickness of 1 mm to 10 mm, particularly preferably 3 mm to 8 mm. The two glass panes are held at a defined distance from each other by the spacer, so that a space between the panes is formed, which is preferably sealed by the circumferential spacer.This space between the panes is preferably filled with an inert gas, for example argon or krypton, to reduce the thermal conductivity through the insulating glazing.

[0039] The spacer (especially its side walls) is preferably connected to the glass panes via a sealant. The sealant is preferably a butyl sealant. An outer sealant is preferably applied to the outer wall, particularly in a peripheral gap between the glass panes, which is bounded by the glass panes and the outer wall of the spacer and is open to the outside. This outer sealant is preferably an organic sealant made of or based on polysulfides, silicones, RTV (room temperature curing) silicone rubber, HTV (high temperature curing) silicone rubber, peroxide-curing silicone rubber and / or addition-curing silicone rubber, polyurethanes, butyl rubber and / or polyacrylates.

[0040] The inner cavity of the spacer is preferably filled with a desiccant. Suitable desiccants include silica gels, molecular sieves, CaCl₂, Na₂SO₄, activated carbon, silicates, bentonites, and / or zeolites.

[0041] Insulating glass consisting of two panes of glass is also called double glazing. However, insulating glass can also comprise three panes of glass (triple glazing) or even more. Such insulating glass can be formed either by arranging a spacer between each adjacent pane of glass, wherein at least one spacer of the insulating glass is a spacer according to the invention, preferably all spacers of the insulating glass. Alternatively, it is also possible for the spacer according to the invention to connect the two outermost panes of glass and for its inner wall to have recesses for the intermediate pane, into which it is inserted.

[0042] The invention also comprises a method for manufacturing a spacer according to the invention. In this process, (a) melted a polymeric base material, (b) added at least one aerogel to the polymeric base material, (c) mixed the polymeric base material with the aerogel, (d) produced a spacer from the polymeric base material with the aerogel.

[0043] The production of the spacer in process step (d) is preferably carried out by extrusion.

[0044] In a first embodiment of the process, the base material is melted (process step (a)), the aerogel is added (process step (b)), the base material and aerogel are mixed (process step (c)) and the spacer is then produced directly from this melt (process step (d)), preferably by extrusion.

[0045] In a second embodiment, the process is carried out in two separate steps. The base material is melted (process step (a)), the aerogel is added (process step (b)), and the base material and aerogel are mixed (process step (c)). After process step (c), granules are produced, which in turn serve as the starting material for the actual production of the spacer. The granules are preferably produced by extrusion. Typically, a granulating device is used, for example, a type of fine perforated plate, through which the mass is extruded and cut off after a short extrusion length. The granules are then melted again, and the spacer is produced from them (process step (d)), preferably by extrusion.

[0046] The second embodiment is preferred. On the one hand, it allows for more robust process control. Problems, for example, during the mixing of the aerogel and base material do not directly lead to a halt in spacer production. Instead, the granules can be kept in stock in larger quantities. On the other hand, this embodiment also allows for the local separation of the two process steps. The granules can be transported. For example, the spacer manufacturer can purchase the granules in pre-fabricated form from a plastics supplier, who typically has greater expertise in plastics processing.

[0047] The melting of the base material and its mixing with the aerogel additive preferably takes place in an extruder, in particular in the extruder used to extrude the spacer (first embodiment) or the granules (second embodiment). A twin-screw extruder is especially preferred because it ensures better mixing than a single-screw extruder. In this process, the base material is conveyed through a heated cylinder by means of two rotating screw shafts and melted in the process.

[0048] The aerogel is added to the base material in a preferred process as a bulk material, particularly as granules or powder. This is advantageous with regard to a good and homogeneous mixing of the base material with the aerogel. The particle size is preferably at most (i.e., less than or equal to) 4 mm, and particularly preferably at most 2 mm.

[0049] If the spacer is also to contain a glass fiber component, glass fibers are added to the base material. In an advantageous process, this is done using the same extruder that is also used to add the aerogel additive.

[0050] However, it is also possible for the aerogel and glass fibers to be added in two separate steps. For example, it is conceivable that the manufacturer of the spacer purchases the base material already mixed with glass fibers and then adds the aerogel itself (especially in the first embodiment).

[0051] Typically, the spacer also contains further additives, referred to in the context of the present invention as "other additives," which are common for industrially processed plastics, in particular stabilizers (for example, UV stabilizers), color additives, and / or processing aids. These can be added to the base material in the same process step as the aerogel and any glass fibers. Alternatively, however, it is possible that the base material is already provided with these other additives in process step (a).

[0052] If the spacer is to be foamed, a foaming agent is added to the plastic mass, for example, in a proportion of 0.1% to 3% by weight. The foaming agent is decomposed, particularly thermally, releasing a gas that leads to the formation of gas-filled pores and thus to the foaming of the material. In the second embodiment, the foaming agent is preferably added to the molten granules from which the spacer is then produced, particularly by extrusion. This allows the degree of foaming, i.e., the properties of the spacer, to be adjusted directly during its production as desired in each individual case.

[0053] The spacer is typically manufactured in process section (d) in the form of straight sections similar to a continuous profile, typically with a unit length. If it is to be installed in insulating glass, the frame-like shape with the required dimensions is created. This can be done by bending, as is common practice for aluminum spacers, provided the polymer spacer is bendable. Bending can be ensured, for example, by a comparatively small fiberglass content and reinforcing strips in the side walls, as proposed in WO2015043848A1, or by an externally applied metallic foil, as disclosed in DE102010006127A1.When bending, the spacer is cut to the required length (whereby several straight spacer sections can first be joined together to form an extended starting piece using a longitudinal connector inserted into the opposing ends of both sections to be joined), bent into the frame-like shape so that the two ends point towards each other, and then the two ends are joined together, for example, by a longitudinal connector or a corner connector inserted into the opposing ends. Alternatively, four straight sections can be cut to length and joined together with corner connectors to form the frame-like spacer.

[0054] Preferably, an insulating film is applied at least to the outer surface of the base body.

[0055] The invention also includes the use of a spacer according to the invention in an insulating glass unit.

[0056] The invention is explained in more detail below with reference to a drawing and exemplary embodiments. The drawing is a schematic representation and not to scale. The drawing does not limit the invention in any way.

[0057] They show: Fig. 1 shows a perspective cross-section through a spacer according to the invention, Fig. 2 shows a cross-section through an insulating glass unit with the spacer made of Figure 1 .

[0058] Figure 1 Figure 1 shows a spacer 1 according to the invention for insulating glass. The spacer 1 is made of a polymeric base material (for example, SAN) to which an aerogel is added. The aerogel component advantageously reduces the thermal conductivity of the spacer 1, thus improving the thermal insulation performance of insulating glass in which the spacer 1 is used.

[0059] Furthermore, in preferred embodiments, the material of the spacer 1 contains a glass fiber component to improve its mechanical properties, particularly its stiffness. In addition, the material of the spacer 1 includes other common additives, such as chemical stabilizers, UV stabilizers, color additives, curing agents, and / or processing aids.

[0060] The material of spacer 1 can be foamed to further reduce thermal conductivity.

[0061] The spacer 1 consists of two parallel side walls, an inner wall and an outer wall, with the inner and outer walls running between the side walls. In the illustration, the side walls run vertically and are designed to be in contact with the glass panes of the insulating glass unit. The inner wall is shown horizontally at the top and is designed to face the inner cavity of the insulating glass unit. The outer wall is shown at the bottom and comprises a flat central section parallel to the inner wall and two flat edge sections arranged at an angle of approximately 135° to the central section and to the adjacent edge sections. The spacer 1 surrounds a cavity designed to be filled with a desiccant.

[0062] Figure 2Figure 1 shows a cross-section through an insulating glass unit in the area of ​​the spacer 1. The insulating glass unit consists of two glass panes 3, 4 made of soda-lime glass, for example, with a thickness of 4 mm, which are connected to each other via the spacer 1 located in the edge region. The side walls of the spacer 1 are connected to the glass panes 3, 4 via a sealing layer 5. The sealing layer 5 is made, for example, of butyl. An outer sealant 6 is applied around the perimeter of the insulating glass unit between the glass panes 3, 4 and the spacer 1. The sealant 6 is, for example, a silicone rubber.

[0063] The cavity of the spacer 1 is filled with a desiccant 7. The desiccant 7 is, for example, a molecular sieve. The desiccant 7 absorbs any residual moisture present between the glass panes 3 and 4, thus preventing condensation on the glass panes 3 and 4 in the space between the panes. The effect of the desiccant 7 is enhanced by holes (not shown) in the inner wall of the spacer 1.

[0064] The outer wall (and typically adjacent sections of each side wall, not shown here) is provided with an insulating film 2, on the surface facing away from the cavity. The insulating film 2 reduces diffusion through the spacer 1. This reduces moisture ingress into the interior of the pane or the loss of the inert gas filling from the interior of the pane. The insulating film 2 also improves the thermal properties of the spacer 1, thus reducing its thermal conductivity. The insulating film 2 comprises, for example, the following layer sequence: a polymeric carrier film (consisting of LLDPE (linear low-density polyethylene), thickness: 24 µm) / a metallic layer (consisting of aluminum, thickness: 50 nm) / a polymeric layer (PET, 12 µm) / a metallic layer (Al, 50 nm) / a polymeric layer (PET, 12 µm).

[0065] The effect of the aerogel additive can be estimated using the following simulations. The thermal conductivity was calculated for various base materials with different aerogel and glass fiber contents. The following thermal conductivity values ​​for the various components were used as a basis, with the thermal conductivity of the spacer being the additive result of the values ​​of its components, each with its corresponding percentage weighting: - SAN (base material): 0.16600 W / (mK) - ABS (base material), foamed: 0.09540 W / (mK) - Fiber optics assuming the following orientation: 0.26943 W / (mK) - Aerogel: 0.01000 W / (mK) The aerogel is Quarzene powder of type Z2TP from the company Svenska Aerogel a hydrophilic silicate-based aerogel with a mean particle size of 12 µm.

[0066] The composition and the calculated thermal conductivity can be found in Table 1. Table 1 ingredient composition Comparative example Example 1 Example 2 Example 3 SAN 65% by weight 65% by weight 65% by weight - ABS, foamed - - - 65% by weight fiber optics 35% by weight 25% by weight 20 wt.% 25% by weight Aerogel - 10 wt.% 15% by weight 10 wt.% Thermal conductivity 0.20220 W / (mK) 0.17626 W / (mK) 0.16329 W / (mK) 0.13037 W / (mK)

[0067] The comparison example is a conventional polymer spacer based on SAN with a comparatively high glass fiber content.

[0068] In Example 1, an aerogel content of 10% is used, with the glass fiber content reduced accordingly to keep the proportion of polymeric base material constant. This results in a 13% reduction in thermal conductivity compared to the reference example.

[0069] In example 2, a higher aerogel content of 15% is used, while the glass fiber content is reduced accordingly. This results in a 19% reduction in thermal conductivity compared to the reference example.

[0070] In Example 3, ABS is used instead of SAN as the base material, and the material is foamed. The aerogel and glass fiber content is the same as in Example 1. There is a 36% reduction in thermal conductivity compared to the reference example. Reference symbol list:

[0071] (1)Spacer (2)Insulating film (3)Glass pane (4)Glass pane (5)Sealing layer (6)Outer sealant (7)Desiccant

Claims

1. Spacer (1) for insulating glazing, made of a material which contains at least one polymeric base material, wherein at least one aerogel is added to the polymeric base material.

2. Spacer (1) according to claim 1, wherein the proportion of the polymeric base material is at least 40 wt.%, preferably at least 50 wt.%, most preferably at least 60 wt.%, and the aerogel proportion is at least 5 wt.%, preferably at least 10%, most preferably from 10 wt.% to 20 wt.%, most preferably from 10 wt.% to 15 wt.%.

3. Spacer (1) according to claim 1 or 2, wherein glass fibers are added to the polymeric base material and wherein the glass fiber content is at least 15 wt.%, preferably at least 20 wt.%, particularly preferably from 20 wt.% to 30 wt.%, most preferably from 20 wt.% to 25 wt.%.

4. Spacer (1) according to any one of claims 1 to 3, wherein the material contains - at least 5 wt.% of the aerogel, preferably at least 10 wt.%, particularly preferably 10 wt.% to 20 wt.%, most preferably 10 wt.% to 15 wt.%, - at least 15 wt.% of glass fibers, preferably at least 20 wt.%, particularly preferably 20 wt.% to 30 wt.%, most preferably 20 wt.% to 25 wt.%, - at most 5 wt.% of other additives, in particular containing stabilizers, color additives, curing agents and / or processing aids, preferably at most 2 wt.%, particularly preferably 0.1 wt.% to 2 wt.%, wherein the remainder is formed by the polymeric base material.

5. Spacer (1) according to any one of claims 1 to 4, wherein the polymeric base material is polypropylene (PP), acrylonitrile butadiene styrene (ABS), acrylonitrile styrene acrylonitrile (ASA), acrylonitrile butadiene styrene polycarbonate (ABS / PC), styrene acrylonitrile (SAN), glycol-modified PET (PETG), polyethylene terephthalate polycarbonate (PET / PC), polybutylene terephthalate polycarbonate (PBT / PC) or copolymers or derivatives or mixtures thereof.

6. Spacer (1) according to any one of claims 1 to 5, wherein the aerogel is a polymer aerogel, a silicate aerogel and / or a cellulose aerogel.

7. Spacer (1) according to any one of claims 1 to 6, wherein the material is foamed and has gas inclusions with a volume fraction of preferably at most 25 vol.%, particularly preferably of 10 vol.% to 15 vol.%.

8. Spacer (1) according to one of claims 1 to 7, which is constructed from two mutually parallel side walls which are connected to each other by an inner wall and an outer wall, wherein the side walls, the inner wall and the outer wall surround a hollow chamber.

9. Spacer (1) according to claim 8, wherein at least the outer wall is provided with an insulating film which preferably contains a polymeric carrier film and at least one metallic or ceramic layer.

10. Insulating glazing comprising at least two parallel glass panes (3, 4) which are connected to each other by a spacer (1) according to one of claims 1 to 9, which is arranged in the edge area between the glass panes (3, 4).

11. Method for producing a spacer (1) according to any one of claims 1 to 9, wherein (a) a polymeric base material is melted, (b) at least one aerogel is added to the polymeric base material, (c) the polymeric base material is mixed with the aerogel, (d) a spacer is produced from the polymeric base material with the aerogel.

12. Method according to claim 11, wherein the aerogel is added in process step (b) in the form of granules or powder, preferably with a particle size of at most 4 mm, particularly preferably at most 2 mm.

13. Method according to claim 11 or 12, wherein after process step (c) a granulate is produced which is melted before process step (d).

14. Method according to one of claims 11 to 13, wherein the spacer (1) is produced by extrusion in process step (d).

15. Method according to any one of claims 11 to 14, wherein the melting of the base material in process step (a) and the mixing of the aerogel with the base material in process step (c) takes place in a twin-screw extruder.

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