Patent ID: 12194325

DETAILED DESCRIPTION OF THE INVENTION

According to a first aspect of the invention, a composite material is provided which is produced by a method comprising the following steps:i) providing a carrier material,ii) providing a plurality of particles of at least one layered, physically acting blowing agent,iii) mixing the carrier material and the layered, physically acting blowing agent to produce a precursor,characterized in that the precursor, during or after step iii), is subjected to a mechanical shaping method in which adjacent particles of the layered, physically acting blowing agent are arranged substantially in parallel with one another over the entire composite material.

One concept of the above-mentioned composite material is to combine a structurally anisotropic, physically intumescent material (layered, physically acting blowing agent) with a carrier material and to use the structural anisotropy of the physically intumescent material, by alignment or orientation of the particles, in order to thus influence the direction of expansion in the event of a fire and to thus be able to control this in a targeted manner. The alignment or orientation of the particles of the layered, physically acting blowing agent in the carrier material is achieved in that the precursor, during or after step iii), is subjected to a mechanical shaping method. In the case of the layered, physically acting blowing agents used in the context of the present invention, expansion takes place in the event of fire substantially in one direction, specifically perpendicularly to the individual layers of which the physically acting blowing agent is formed. If the adjacent particles of the layered, physically acting blowing agent are now arranged substantially in parallel with one another over the entire composite material, in the event of heat input expansion takes place substantially perpendicularly to the parallel particles and it is possible to control the expansion in a desired direction.

For a better understanding of the invention, the following explanations of the terminology used herein are considered useful. In the context of the invention:the term “composite material” describes a material which is obtained during production by firmly combining different materials and of which the chemical and physical properties exceed those of the individual components;the term “carrier material” describes a composition comprising one or more polymers. The carrier material is characterized in that the polymer or polymers form a continuous phase;the term “firmly bonded” describes a bond between two materials which results from molecular forces and holds the layers together in such a way that they form a solid body in their entirety. The separation of a firm bond is often possible only by destroying the elements that were connected to one other by a firm bond.the term “form-fitting” describes a connection between two materials which results from at least two connecting parts interlocking. In the context of the present invention, a form-fit connection can be produced in particular by the plastic deformability of the polymeric carrier material being used to bring about interlocking.“physical intumescence” means the formation of a voluminous, insulating layer by means of expansion of a compound that releases gases, without a chemical reaction between two compounds having taken place, thereby causing the volume of the compound to increase by a multiple of the original volume. In the context of the present invention, the term “physically acting blowing agent” means a material or a component which is capable of exhibiting physical intumescence when a certain temperature, the so-called activation temperature, is exceeded;the term “thermal expansion” or simply “expansion” means the volume increase of a material or a component caused by physical and/or chemical intumescence;a “polymer” is a molecule having six or more repetition units, which can have a structure that can be linear, branched, star-shaped, twisted, hyper-branched or crosslinked; polymers can have a single type of repetition unit (“homopolymers”) or they can have more than one type of repetition unit (“copolymers”);the term “solids content” means the content of non-volatile proportions of a composition. The solids content is determined according to DIN EN ISO 3251 (2008);“contain” and “comprise” mean that further constituents may be present in addition to those mentioned. These terms are intended to be inclusive and therefore encompass the term “consist of.” “Consist of” is intended to be exclusive and means that no further constituents may be present. In a preferred embodiment, the terms “contain” and “comprise” mean the term “consist of”;a range limited by numbers, e.g. “5 to 60 wt. %,” means that the two extreme values and any value within this range are disclosed individually.

Step i) for producing the composite material according to the invention comprises providing a carrier material. The carrier material preferably comprises a polymer dispersion based on water or solvent, in particular an aqueous polymer dispersion. Examples of aqueous polymer dispersions which have proven particularly useful are aqueous acrylate dispersions, aqueous dispersions or emulsions of urea resins, formaldehyde resins or melamine resins, polyvinyl acetates, polyvinyl alcohols, acrylonitrile, styrene acrylates and their copolymers.

The carrier material of the composite material according to the invention preferably comprises an aqueous acrylate (copolymer) dispersion, more preferably an aqueous dispersion of a polyalkyl (meth)acrylate and/or an alkyl (meth)acrylate copolymer. These are preferably aqueous dispersions which are obtained by polymerization, in particular by emulsion polymerization of alkyl (meth)acrylates and/or by copolymerization of alkyl (meth)acrylates with themselves and/or with copolymerizable comonomers, such as preferably (meth)acrylic acid, (meth)acrylamide, styrene, itaconic acid, acrylonitrile and/or citraconic acid, wherein the alkyl groups of the alkyl (meth)acrylates preferably have 1 to 6 C atoms, more preferably 1 to 4 C atoms. Particularly preferred according to the invention are aqueous dispersions of polybutyl acrylate, polyethylhexyl acrylate or alkyl (meth)acrylate-styrene copolymers. The acrylate (copolymer) dispersion may contain both homopolymers and copolymers or mixtures of homopolymers and/or copolymers and, preferably with a pH in the range of from 7 to 9, preferably a pH of 8, which is adjusted if necessary with dilute sodium hydroxide solution or ammonia solution, is mixed with the other constituents. This aqueous acrylate (copolymer) dispersion preferably has a solids content of from 40 to 90 wt. %, more preferably 50 to 80 wt. %. The acrylate (copolymer) dispersions preferably used according to the invention are known to a person skilled in the art and are commercially available. The curing takes place physically by drying.

It is further preferred for the carrier material to have a softening or decomposition point in the temperature range of from 80° C. to 500° C., preferably from 90° C. to 400° C., more preferably from 110° C. to 300° C. By appropriately selecting the softening or decomposition temperature of the carrier material, the expansion properties of the composite material according to the invention can be influenced. If premature softening or decomposition of the carrier material occurs in the event of a fire, this may possibly lead to a reorientation of the particles of the layered, physically acting blowing agent by deformation and/or melting of the carrier material. If the softening or decomposition temperature of the carrier material is too high, the expansion of the layered, physically acting blowing agent is hindered.

The carrier material may further comprise at least one organic and/or inorganic fiber which is selected in particular from the group consisting of glass fiber, ceramic fiber, carbon fiber, polyamide fiber, metal fiber, boron fiber, natural fiber, rock fiber and mixtures thereof. The presence of an organic and/or inorganic fiber in the carrier material facilitates the incorporation and orientation of the layered, physically acting blowing agent into the carrier material. Particularly suitable fibers are glass fibers and/or metal fibers, in particular consisting of E-glass, silicate fibers or mineral wool fibers.

The organic or inorganic fibers preferably have a length of from 1 mm to 25 mm, more preferably from 2 mm to 20 mm, and particularly preferably from 3 mm to 15 mm. By way of example, glass fibers from STW may be mentioned here.

The organic or inorganic fibers are preferably contained in the carrier material in an amount of from 0.1 to 25.0 wt. %, preferably from 0.5 to 15.0 wt. %, particularly preferably from 1.0 to 6.0 wt. % based on the total weight of the solids content of the composite material.

It is particularly preferred for the longitudinal extent of the organic and/or inorganic fiber to be substantially parallel to the particles of the layered, physically acting blowing agent. In this case, the organic and/or inorganic fibers support the effect of the expansion being targeted in one spatial direction in the event of a fire.

Because the ash crust formed in the event of a fire may be too unstable and, depending on its density and structure, may therefore be blown away by air streams, which has a negative effect on the sealing effect of the fire protection element, the carrier material may additionally contain at least one ash crust stabilizer.

An “ash crust stabilizer” is a so-called skeleton-forming compound which stabilizes the carbon skeleton (ash crust) formed from the physically acting blowing agent and the carrier material. In this connection, the fundamental mode of action is that the inherently very soft carbon layers being formed are mechanically strengthened by inorganic compounds. The addition of such an ash crust stabilizer contributes to significant stabilization of the intumescence crust in the event of a fire, because these additives increase the mechanical strength of the intumescent layer and/or prevent it from falling off, as a result of which the insulating effect is maintained or enhanced.

The compounds commonly used in fire protection formulations and known to a person skilled in the art, for example particulate metals, such as aluminum, magnesium, iron and zinc, may be considered as ash crust stabilizers or skeleton-forming substances. The particulate metal can be present in the form of a powder, flakes, scales, fibers, threads and/or whiskers, the particulate metal in the form of powder, flakes or scales having a particle size of ≤50 μm, preferably of from 0.5 to 10 μm. If the particulate metal is used in the form of fibers, threads and/or whiskers, a thickness of from 0.5 to 10 μm and a length of from 10 to 50 μm are preferred. Alternatively or additionally, an oxide or a compound of a metal of the group comprising aluminum, magnesium, iron or zinc may be used as the ash crust stabilizer, in particular iron oxide, preferably iron trioxide, titanium dioxide, and/or a borate such as zinc borate. Examples of such additives are also found in U.S. Pat. Nos. 4,442,157 A, 3,562,197 A, GB 755 551 A, as well as EP 138 546 A1.

Preferably, the ash crust stabilizer is a phosphorus-containing compound selected from salts and derivatives of the oxoacids of phosphorus. The oxoacids of phosphorus are used because their range is very large.

As phosphoric acid compounds, the following may be mentioned by way of example: monoammonium phosphate, diammonium phosphate, ammonium phosphate, ammonium polyphosphate, melamine phosphate, melamine resin phosphates, potassium phosphate, polyol phosphates such as, for example, pentaerythritol phosphate, glycerol phosphate, sorbitol phosphate, mannitol phosphate, dulcitol phosphate, neopentyl glycol phosphate, ethylene glycol phosphate, dipentaerythritol phosphate and the like. Preferably, a polyphosphate or an ammonium polyphosphate is used as a phosphoric acid compound. In this regard, melamine resin phosphates are understood to be compounds such as the reaction products of Lamelite C (melamine-formaldehyde resin) with phosphoric acid.

The ash crust stabilizer is preferably contained in the carrier material in an amount of approximately 5 to 35 wt. %, preferably 7 to 30 wt. %, particularly preferably 10 to 28 wt. %, based on the total weight of the solids content of the composite material.

In addition, other fire protection additives, in particular those which cause chemical intumescence, and those which act ablatively, may be contained in the composition. “Chemical intumescence” means the formation of a voluminous, insulating ash layer by means of compounds which are coordinated with one another and which react with one another under the effect of heat. These are generally a carbon source, an acid former and a gas former.

A “carbon source” is an organic compound which, due to incomplete combustion, leaves behind a carbon skeleton and is burned incompletely to form carbon dioxide and water (carbonization). These compounds are also known as “carbon-skeleton-forming substances.” An “acid former” is a compound which, under the effect of heat, i.e. above approximately 150° C., forms a non-volatile acid, for example due to decomposition, and thereby acts as a catalyst for carbonization. In addition, it may contribute to lowering the viscosity of the melt of carrier material; the term “dehydrogenation catalyst” is used synonymously in this context. A “gas former” is a compound which decomposes at an elevated temperature with the development of inert, i.e. non-combustible, gases and expands the carbon skeleton formed by the carbonization and optionally the softened binder into a foam (intumescence).

Optionally, the carrier material may contain other conventional additives, such as plasticizers, fillers, pigments, additives for adjusting the rheological properties, thickeners, dispersants, emulsifiers, biocides, fungicides, preservatives and anti-aging agents, antifreeze agents, wetting agents, defoamers and/or skin-formation retardants. These other additives are commercially available products known to a person skilled in the art.

Fillers which can be used are the fillers commonly used and known to a person skilled in the art. The following can be mentioned by way of example as fillers: chalk, barium sulfate, quartz, talc, kaolin, calcium sulfate and/or calcium silicate. The filler may be used alone or as a mixture of two or more.

As pigments, the carrier material may preferably contain iron oxide, titanium dioxide, zinc sulfide, zinc oxide and/or organic or inorganic color pigments.

The carrier material may for example contain highly dispersed silica, bentonites or modified bentonites, polyacrylates and/or cellulose derivatives, such as cellulose ethers, as additives for adjusting the rheological properties.

The additives may be contained in the carrier material in an amount of from approximately 0.25 to 2.5 wt. %, preferably 0.5 to 1.7 wt. %, particularly preferably 0.8 to 1.6 wt. %, based on the sum of the solids content of the composite material.

Step ii) for producing the composite material according to the invention comprises providing a plurality of particles of at least one layered, physically acting blowing agent. In the context of the present invention, the term “layered” is understood to mean a material which is structurally anisotropic in the form of layers. The layered structure is due to the fact that the interactions within a layer are much more pronounced than between the layers. In the context of the present invention, this means in particular that covalent bonds are present within the layers, with only weak interaction in the form of electrostatic and/or van der Waals forces acting between the layers. The layered, physically acting blowing agent comprises a plurality of particles. It is essential to the invention that adjacent particles of the layered, physically acting blowing agent are arranged substantially in parallel with one another over the entire composite material owing to the mechanical shaping method.

Preferably, the layered, physically acting blowing agent is in the form of flakes, the adjacent flakes being arranged substantially in parallel with one another over the entire composite material.

The average particle size of the layered, physically acting blowing agent can be within a broad range depending on the application. Preferably, the layered, physically acting blowing agent has an average particle size of from 50 μm to 4.0 mm, preferably from 80 μm to 3.5 mm and particularly preferably from 100 μm to 3.0 mm. The average particle size can be determined by the methods known to a person skilled in the art, for example by means of sieving analysis according to DIN 66165 (2016).

The layered, physically acting blowing agent is preferably selected from the group consisting of graphite intercalation compounds (also known as expandable graphite) phyllosilicate intercalation compounds and combinations thereof, with graphite intercalation compounds or expandable vermiculite being preferred.

Known intercalation compounds of SOx, NOx, halogen, acetic acid, nitric acid and/or strong acids in graphite can be considered as examples of graphite intercalation compounds. These are also referred to as graphite salts. Graphite intercalation compounds that give off SO2, SO3, NO and/or NO2while expanding at temperatures (activation temperatures) of from 120 to 350° C., for example, are preferred. Expandable graphites suitable for the present invention are commercially available.

Preferably, the graphite intercalation compounds have an average particle size of from 50 μm to 1.0 mm, preferably from 70 μm to 0.7 mm and particularly preferably from 90 μm to 0.5 mm.

Suitable phyllosilicate intercalation compounds (expandable phyllosilicates) are, for example, those compounds which can be obtained by incorporation of intercalation compounds into native, expandable phyllosilicates, in particular native vermiculite. Representatives of the alcoholates of lithium and potassium and salts of lithium, sodium and potassium with organic acids and/or aqueous solutions thereof, which are incorporated into the native phyllosilicate by cation exchange, are preferred as the intercalation compound. In this regard, reference is made to DE 1029083 A1 and the literature cited therein, e.g. EP 0 429 246 A1, the contents of which are hereby incorporated into this application.

The phyllosilicate intercalation compounds preferably have an average particle size of from 100 μm to 4.0 mm, preferably from 120 μm to 3.5 mm and particularly preferably from 150 μm to 3.0 mm.

Step iii) for producing the composite material according to the invention comprises mixing the carrier material and the layered, physically acting blowing agent to produce a precursor. The mixing of the carrier material and the layered, physically acting blowing agent to produce a precursor takes place preferably in a multi-component mixing system. A precursor is obtained in which the layered, physically acting blowing agent is homogeneously and isotropically distributed within the carrier material.

Depending on the application, the layered, physically acting blowing agent can be present in the precursor, and correspondingly also in the composite material, in a very broad weight percent range. However, it is preferred for the layered, physically acting blowing agent to be contained in the composite material in an amount of from 10 to 90 wt. %, preferably from 15 to 70 wt. %, more preferably from 20 to 55 wt. %, based on the total weight of the solids content of the composite material.

In order to produce the composite material according to the invention, it is essential to the invention that the precursor, during or after step iii), is subjected to a mechanical shaping method in which adjacent particles of the layered, physically acting blowing agent are arranged substantially in parallel with one another over the entire composite material.

It is essential to the present invention that adjacent particles of the layered, physically acting blowing agent are arranged substantially in parallel with one another over the entire composite material. In the event of a fire, the layered, physically acting blowing agent expands substantially perpendicularly to the layers from which it is constructed. A substantially parallel alignment of adjacent particles over the entire composite material ensures that the expansion takes place substantially in one spatial direction. The substantially parallel alignment of the particles thus allows spatial control of the expansion behavior in the event of a fire. When using the composite material according to the invention as or in a fire protection element, it is thus possible to steer the expansion in a reinforced manner in the direction of the passage opening to be closed and thus to reduce or prevent lateral pushing-out out of the passage opening. The layered, physically acting blowing agent used is available to a great extent for the closure of the passage opening such that the closure ability is improved overall, which is associated with a significant reduction in the use of material with respect to the layered, physically acting blowing agent.

The term “over the entire composite material” in the context of the present invention is understood to mean that, when considering the orientation of adjacent particles of the layered, physically acting blowing agent, an overall consideration of the composite material is necessary and the substantially parallel orientation of adjacent particles has to be present substantially for the entire volume of the composite material in order to lead to the essential effect according to the invention. A local, random parallel arrangement of adjacent particles in parts of the composite material does not lead to the effect essential to the invention of a directed expansion in the context of the invention. However, due to the fact that the orientation is considered at the level of the individual particles and their adjacent particles, it is not absolutely necessary for all of the particles of the layered, physically acting blowing agent to have a substantially parallel alignment. If, for example, there is a bending of the composite material during application, the adjacent particles of the layered, physically acting blowing agent are arranged substantially in parallel, but not all particles are arranged substantially in parallel with one another due to the bending of the composite material.

The term “substantially in parallel” in the context of the present invention is understood to mean that the adjacent particles do not have to satisfy the strictly mathematical requirements of parallel planes, but rather slight tilting of the planes is also permitted. Even with slight tilting of the planes, the above-described effect of an expansion occurring substantially in one spatial direction is still ensured. Furthermore, the term “substantially in parallel” in the context of the present invention also includes a situation whereby a small proportion of adjacent particles need not be arranged in parallel, which may be for production-related reasons, for example. Preferably, at least 75%, more preferably at least 80%, more preferably at least 85%, more preferably at least 90%, more preferably at least 95% of the adjacent particles of the layered, physically acting blowing agent show a parallel arrangement.

The substantially parallel arrangement of the adjacent particles of the layered, physically acting blowing agent over the entire composite material can be determined by visual inspection of the composite material, optionally with the aid of a microscope, by a person skilled in the art.

A quantification of any tilting of the particles that may be present can theoretically be described by a perpendicular (90°) being allowed to fall on an arbitrarily selected particle of the layered, physically acting blowing agent. Upon displacement of this perpendicular with respect to particles adjacent to this particle, there is preferably a maximum angular deviation from 90° of 25°, more preferably 15°, more preferably 10°, more preferably 5° and even more preferably 2°.

The term “adjacent particles” in the context of the present invention is understood to mean those particles which are in close proximity to a particular particle in all three spatial directions, i.e. which are arranged within a first sphere around a particle. Preferably, the term “adjacent particles” does not only mean the directly adjacent particles, but also those particles which are directly adjacent to the directly adjacent particles of a particle, i.e. particles which go beyond the first sphere and are arranged around a particle within a second sphere.

During production of the composite material according to the invention, adjacent particles of the layered, physically acting blowing agent are arranged substantially in parallel with one another over the entire composite material by the mechanical shaping method. It follows that, within the composite material, all particles of the layered, physically acting blowing agent can be arranged substantially in parallel with one other. This constitutes a preferred embodiment of the present invention.

However, a substantially parallel alignment of all particles of the layered, physically acting blowing agent is not absolutely necessary in order to achieve the effect essential to the invention of a targeted expansion in substantially one spatial direction. This is for example the case when the composite material according to the invention is in the form of a long bandage which is wound for example around a conduit guide which passes through a passage opening. In this case, the adjacent particles of the layered, physically acting blowing agent are arranged substantially in parallel, but not all particles are arranged substantially in parallel with one another due to the winding and the associated bending of the bandage. If the adjacent particles are arranged in this case in the longitudinal direction of the bandage substantially in parallel with one another over the entire composite material, the expansion in the event of a fire takes place substantially in the direction of the center of the passage opening.

Preferably, the mechanical shaping method is selected from the group consisting of extrusion with shaped mouthpieces in specific geometries, injection molding, squeegeeing, calendering, pultrusion, and combinations thereof. Preferably, the mechanical shaping method is selected from extrusion with shaped mouthpieces in specific geometries and/or calendering.

Within the context of the present invention, the term “extrusion” is understood to mean pressing a mass out of a shaping opening under pressure. The shaping opening is also referred to as a mouthpiece. Preferably, the extrusion is carried out using a piston extruder or a screw extruder. The use of mouthpieces with special geometries in which the ratio of height to length is as small as possible allows the alignment of the adjacent particles of the layered, physically acting blowing agent over the entire composite material. Advantageously, the dimensions of the mouthpiece (length:height) are in a range of from 310 mm:10 mm to 7 mm:0.5 mm. It is further preferred that the maximum height of the mouthpiece is ≤10 mm, more preferably ≤5 mm, in particular ≤2 mm, more preferably ≤1.5 mm, and particularly preferably ≤1.0 mm.

Within the context of the present invention, the term “squeegeeing” is understood to mean a method in which the precursor is applied to a surface using a squeegee.

Within the context of the present invention, the term “calendering” is understood to mean a method in which a calender comprising one or more rollers is used. The precursor prepared in step iii) is passed once or several times through the gap of the roller. It is advantageous if this step is performed several times, for example 4 or 5 times. In this case, it is also advantageous if the spacing between the rollers is slightly reduced with each step. Preferably, the rolls have a spacing of ≤10 mm, more preferably a spacing in the range of from 0.5 mm to 8 mm, more preferably from 1.0 mm to 5.0 mm, and most preferably from 1.0 to 3.0 mm.

Within the context of the present invention, the term “pultrusion” is understood to mean a method in which the precursor is applied to a material for pulling, such as a glass fiber woven fabric, and a pulling force is then exerted on this material.

Within the context of the present invention, the term “injection molding” is understood to mean a method in which the precursor is liquefied in an injection-molding machine and injected into a mold under pressure.

According to a preferred embodiment, the composite material according to the invention is a moldable mass or as a molded part, in particular in the form of strips, rings or plates.

The composite material preferably has a maximum average layer thickness of ≤10 mm, more preferably ≤8 mm, and particularly preferably ≤5 mm. In a preferred embodiment, the composite material has an average layer thickness of from 0.5 mm to 4.6 mm.

DESCRIPTION OF THE DRAWINGS

Embodiments will be explained in more detail with reference to the accompanying drawings.

FIG.1is a cross section of an embodiment of a composite material according to the invention;

FIG.2is a schematic view of a composite material that is preferred according to the invention;

FIG.3is a photograph of a fire protection element known from the prior art with expandable graphite embedded in a polymeric carrier material;

FIG.4is a photograph of a test setup;

FIG.5shows the graphical evaluation of the expansion attempts of a composite material according to the invention in comparison to fire protection elements known from the prior art.

FIG.1is a cross section of a composite material (1) according to the invention. The composite material (1) comprises a carrier material (2) and at least one layered, physically acting blowing agent (3). Adjacent particles of the layered, physically acting blowing agent (3) are arranged substantially in parallel with one another. The layered, physically acting blowing agent (3) is embedded within the carrier material (2) and is distributed substantially uniformly within the carrier material (2).

FIG.2is a three-dimensional view of a composite material (1) that is preferred according to the invention. The particles of the layered, physical blowing agent (3) are shown in the form of flat cuboids. Adjacent particles of the layered, physical blowing agent (3) are arranged in parallel with one another over the entire composite material (1).FIG.2shows a preferred embodiment in which all the adjacent particles of the layered, physical blowing agent (3) are arranged in parallel with one another over the entire composite material (1).

FIG.3is a photograph of a microscopic analysis (25 times magnification) of a composite material (4) known from the prior art which is used as an intumescent inlay in a fire protection sleeve (Hilti, CP644 fire protection sleeve, layer thickness of the composite material 4.5 mm). The inlay was produced by means of extrusion using a standard die and comprises a plurality of expandable graphite particles (6) embedded in a polymeric carrier material (5). The microscopic analysis shows that the individual expandable graphite particles (6) are aligned in the machine direction. A view of the entire inlay shows an isotropic and random alignment of the individual expandable graphite particles (6) along the machining plane, in which adjacent expandable graphite particles can be arranged in parallel with one another at individual local points. The photograph shows that there is no substantially parallel orientation of adjacent expandable graphite parts (6) over the entire inlay.

FIG.4is a photograph of a test setup by means of which the substantially parallel arrangement of adjacent particles of the layered, physically acting blowing agent can be established.

FIG.5shows the graphical evaluation of the expansion attempts of a composite material according to the invention in comparison to fire protection elements known from the prior art.

The invention is not limited to the embodiments shown. In particular, individual features of one embodiment can be contained independently of the other features of the corresponding embodiment in a further embodiment according to the invention, i.e. the features described can be combined with one another as desired.

According to a second aspect of the present invention, a method for producing the composite material according to the invention is provided, comprising the following steps:i) providing a carrier material,ii) providing a plurality of particles of at least one layered, physically acting blowing agent,iii) mixing the carrier material and the layered, physically acting blowing agent to produce a precursor,

characterized in that the precursor, during or after step iii), is subjected to a mechanical shaping method in which adjacent particles of the layered, physically acting blowing agent are arranged substantially in parallel with one another over the entire composite material.

The above statements on the production of the composite material according to the invention apply similarly to the method according to the invention.

The composite material according to the invention is suitable for use as a fire protection element or for being integrated into a fire protection element. Therefore, according to a third aspect of the present invention, a fire protection element is provided which comprises the composite material according to the invention.

The fire protection element according to the invention can be configured in all forms that geometrically allow the use as a fire protection element. In a preferred embodiment, the fire protection element is strip-shaped and is in the form of an endless bandage.

The fire protection element according to the invention may comprise one or more composite materials according to the invention. If the fire protection element comprises more than one composite material, it is advantageous, if two or more composite materials are layered, to arrange a functional layer between the composite materials. The functional layer preferably extends continuously between the two or more composite materials. Preferably, the functional layer comprises at least one semi-rigid material or the functional layer preferably consists of the at least one semi-rigid material. In the context of the present invention, the term “semi-rigid material” is understood to mean a material which has both sufficient mechanical strength to be able to absorb the inflation pressure emanating from the composite material without being destroyed and sufficient flexibility such that the expansion of the layered, physically acting blowing agent is not hindered. It has proven advantageous for the semi-rigid material to be selected from the group consisting of expanded metal, glass fibers, aluminum foil and combinations thereof.

The present invention further relates to the use of a composite material according to the invention as a fire protection element for sealing passage openings and/or joints in components.

The invention will be explained in more detail with reference to the following examples.

EXAMPLES

A formulation was prepared with the constituents listed in Table 1 below, and the indicated constituents were mixed together. The formulation prepared comprises a carrier material as well as a layered, physically acting blowing agent and can be used as a starting material for the production of a composite material according to the invention.

TABLE 1Constituents formulation for the preparation of a compositematerial according to the invention [wt. %]1Aqueous acrylate dispersion (65% acrylate38.1and 35% water)Expandable graphite (Kaisersberg)26.5Short-cut glass fibers (diameter ~10 μm,4.4length 6 mm)Ammonium polyphosphate18.3Melamine polyphosphate5.3Dipentaerythritol7.4

To produce a composite material according to the invention, a defined amount of the above formulation was applied to a PE film having a smooth surface and the starting material was then covered on both sides by wrapping the PE film. The starting material covered with PE film (layer thickness 10 mm) was calendered (distance between the rollers in the calender between 0.5 mm and 10.0 mm). The distance between the rollers of the calender was reduced in steps of 1 mm and the aforementioned steps were repeated until the desired layer thickness was reached. To smooth the surface, the last processing step was carried out twice with the calender. Alternatively, this step was performed by applying pressure via a roller. The composite materials thus produced exhibit a substantially parallel alignment of the layered, physically acting blowing agent within the carrier material, which was determined by means of visual inspection under a microscope.

Furthermore, a composite material according to the invention (composite material2) was produced according to the above description, where the starting material of the product CP 648-E from Hilti was used as a formulation. This formulation comprises a carrier material (aqueous acrylate dispersion) and a layered, physically acting blowing agent.

To determine the expansion properties of the composite materials produced, a device for function replacement testing was used to determine the amount of expansion (upward direction of expansion). For comparison, the so-called expansion factor can be determined from these measurements, which represents the quotient of the expansion height of the composite material with respect to the total weight of the composite material. The measuring device for performing the function replacement test consisted of two horizontally arranged heatable plates. The top plate had a constant weight. Composite materials to be measured (circular with a diameter of 45 mm) were arranged between the heatable plates and subjected to a temperature program (starting temperature 50° C., heating rate 20° C./min, intermediate temperature 100° C. (5 min), heating rate 20° C., final temperature 500° C. (15 min hold time). The top plate was able to record expansion in height.

In order to show a substantially parallel alignment of adjacent particles of the layered, physically acting blowing agent over the entire composite material, the following test setup was selected. 4.5 mm and 5.00 mm thick strips were cut from the relevant composite material and these strips were rolled up as shown inFIG.2. A strip was rolled up (Example 2) such that the expansion takes place in the x-direction (=height) and a strip was rotated by 90° (Example 1) such that the expansion takes place in a planar direction.Example 1: rolled sample by 90°, assumption: predominantly planar expansion;Example 2: rolled sample, assumption: expansion predominantly in height;Example 3: punched-out reference sample, 45 mm diameter.

In addition to the expansion height, the total surface area of the expanded samples was determined by software with reference to photographs.

TABLE 2Expansion heights and total surface areas of compositematerials 1 and 2, slight deviations fromthe theoretical expansion behavior can beattributed to the sample preparation.SampleTotalCompositeMassthicknessExpansionsurfacematerial[g][mm]height [mm]area [cm2]1Ex. 15.555.07.12137Ex. 25.775.011.7089Ex. 35.765.017.31712Ex. 19.404.57.88186Ex. 29.444.514.93120Ex. 39.304.515.71126

It was found that all samples according to Example 1 had only a low expansion height, but demonstrated a large increase in the total surface area. The samples of composite materials1and2according to Examples 2 and 3 have expanded significantly more in height in comparison, whereas the total surface area remained significantly smaller.

Furthermore, the expansion characteristics of the composite material2of the present invention were examined, using the above-described device for functional replacement testing, in comparison with the expansion characteristics of the commercially available product Fi-Block—Firewrap (available in 2 thicknesses: 0.9 mm and 2.45 mm) from Sekisui, Japan. This product is based on a polymeric carrier material in which expandable graphite is embedded. To determine the expansion properties of the commercially available Fi-Block Firewrap, circular samples weighing 1.60 g (0.9 mm thickness) and 6.33 g (2.45 mm thickness) were punched out. These samples were placed in the device for functional replacement testing, the temperature program was started and the upward expansion was measured. The results in comparison with the results of the expansion of the composite material according to the invention are shown inFIG.5. It has been shown that the samples that are not according to the invention exhibit a substantially lower expansion height than the composite materials according to the invention. Furthermore, the occurrence of a negative expansion height in the samples that are not according to the invention can be explained by a melting of the polymeric carrier material which takes place before the expansion of the expandable graphite takes place.