AU2011269334A1

AU2011269334A1 - A ventilation grid and method of forming a ventilation grid by moulding

Info

Publication number: AU2011269334A1
Application number: AU2011269334A
Authority: AU
Inventors: Edwin Gauch; Bernhard Ludecke; Michael Raab
Original assignee: Promat GmbH
Current assignee: Promat GmbH
Priority date: 2010-06-23
Filing date: 2011-06-22
Publication date: 2013-02-07
Anticipated expiration: 2031-06-22
Also published as: ES2625465T3; WO2011160832A3; PT2585518T; EP2585518B1; DK2585518T3; DE202011050518U1; DE202010009459U1; LT2585518T; PL2585518T3; SI2585518T1; HUE032084T2; AU2011269334B2; EP2585518A2; HRP20170733T1; WO2011160832A2

Abstract

The invention relates to an intumescent composition containing a polymer binding agent, expandable graphite and at least one inorganic filler. The invention also relates to an intumescent moulded body which is produced by means of injection moulding of said type of composition, in particular a ventilation grid for preventing the passage of fire and smoke in the event of a fire from one room into another.

Description

1 Intumescent injection moulding material and moulded body produced therefrom, in particular fireproof grid The present invention relates to an intumescent composition containing a polymer binding agent, expandable graphite (exfoliated graphite), and at least one inorganic filler as well as an intumescent moulded body, which is manufactured by injection moulding such a composition, in particular a ventilation grate that during a fire prevents fire and smoke from passing from one room into another. Compositions of the type previously mentioned are disclosed in the prior art. For example, document DE 100 24 421 Al discloses a fire retardant, intumescent mixture that has a polymer, which can be produced from ethylene, vinyl acetate, and optionally further monomers, with a vinyl acetate content of 40 to 85% by weight. The mixture furthermore contains intumescent graphite, a mineral filler, and optionally additional additives. The mixture described here is used to manufacture moulded bodies, the shaping procedure being performed by extrusion, calendering or compression moulding. With such mixtures, it is considered to be partially disadvantageous that while dimensionally stable moulded bodies can be produced, they can be produced only by the above-mentioned shaping procedures. This is due to the fact that the mixture is relatively hard because of the desired rigidity the moulded bodies are intended to possess. This problem cannot be obviated by increasing the processing temperature since this would heat the exfoliated graphite beyond its trigger temperature ("onset temperature"), which would then cause it to react during production. Finally, the shape variety of moulded bodies that can be produced with such a mixture is limited by such shaping procedure. Finer structures can be manufactured with undue difficulty or with only considerable outlay. Moreover, the length of the production cycle is relatively long. The problem addressed by the present invention thus consists in providing an intumescent composition that can be worked in a manner more conducive to ease of shaping and with which more complex and more intricate structures above all can be manufactured. Moreover, it would be desirable to reduce the time required to produce moulded bodies from such compositions.

2 This problem is solved by an intumescent composition containing a polymer binding agent, expandable graphite (exfoliated graphite), and at least one inorganic filler, wherein the composition is characterized in that it can be injection moulded and the polymeric binding agent has a thermoplastic polymer with a softening point of 160'C or less. The invention is based on the knowledge that by using thermoplastics with a maximum softening point of 160'C, such compositions can be processed in an injection-moulding unit. More complex structures can be manufactured in this manner, such as fireproof grids. The thermoplastic polymer used according to the invention is furthermore characterized by a softening point that is below the "onset temperature" of the expanding graphite, that is to say the temperature at which the expanding graphite begins to swell. In this manner, an already partial activation of the intumescent components during the production of moulded bodies composed of such compositions can be prevented. Moreover, owing to its suitability for injection moulding, the composition according to the invention permits the production of moulded bodies in bulk, that is to say with short station times and favorable reproducibility. The softening point of the thermoplastic polymer is conventionally determined using dynamic differential scanning calorimetry (DSC) according to DIN EN ISO 111357-1, DIN 53 765 or ASTM D 3418. The softening point or the glass transition temperature of the binding agent used according to the invention is < 170'C in particular. The softening point or the glass transition temperature (Tg) as well is customarily determined using dynamic differential scanning calorimetry (DSC) according to DIN EN ISO 111357-1, DIN 53 765 or ASTM D 3418. The thermoplastic polymer or polymer mixture used according to the invention advantageously has a softening point of at least 50'C, more preferred of at least 60'C. Especially preferred is when the softening point is maximally 160'C, preferably at maximally 150'C, most preferred at maximally 130'C. These maximal softening points ensure that the active ingredient, which intumesces in the event of a fire, is not activated during processing.

3 In manufacturing the intumescing composition, the individual components are mixed together in the simplest case, wherein the thermoplastic polymer is expediently used as granules. It is, however, equally possible initially to fuse the thermoplastic polymer and to then mix the remaining components with the melt, which can occur in an extruder, for example. The exfoliated graphite and the inorganic filler can independently thereof be used as, for example, a powder and/or granules. The invention provides that the composition contains expandable graphite that is often designated as exfoliated graphite. This includes commercial expandable graphite intercalation compositions. Owing to the layered structure of graphite, atoms or small molecules can intercalate or be embedded between carbon layers. An expandable graphite salt or GIC (graphite intercalation composition) results therefrom. High-purity exfoliated graphites have a large proportion of intercalated layers. Under the effect of heat, the layers are pulled apart like an accordion through thermolysis, by means of which the graphite flakes expand. Depending on the type of graphite, the expansion can already begin at approximately 150'C and almost suddenly. With free expansion, the final volume can reach hundreds of times that of the initial volume. Such expandable graphite intercalation compounds are produced, for example, by dispersing graphite particles in a solution that contains an oxidizing agent and the compound to be intercalated. Nitric acid, potassium chlorate, chromic acid, potassium permanganate, hydrogen peroxide and the like are often used as oxidizing agents. Concentrated sulfuric acid, for example, is used as a compound to be intercalated. The conversion occurs at temperatures from 60'C to 130'C over a period of up to four hours. Thereafter, the excess of acid is separated, the remaining acid present in the solid product is removed through multiple washings with water, and the material is subsequently dried. Such a production process is described in EP 0 085 121 B1, for example. Examples of expandable silicates used are, for example, phyllosilicates such as vermiculite. Phyllosilicates are constructed of octaeder- and tetraeder layers between which exchangeable cations such as magnesium and aluminum cations are intercalated, the proportions of which vary according to the origin of the phyllosilicate. Owing to the presence of intermediate layer water, such expandable phyllosilicates undergo expansion upon heating due to spontaneous release of the intermediate layer water. This causes the layers to be moved apart and thus an 4 increase in volume. The temperature at which this expansion process begins is designated as onset temperature, which is about 320'C for native expandable vermiculite. In a manner similar to that with exfoliated graphite, other compounds can also be intercalated in the interstitial layers of phyllosilicates, which causes onset temperatures to vary and particularly a shifting to lower temperatures. In this manner, the response characteristic of the intumescent material can adapt to the requirements. In addition to phyllosilicates as expanding silicate material, sodium silicate or potassium silicate can be used singularly or in combination. They are conventionally used in the form of sodium silicate or potassium silicate in the production of the grid according to the invention. The composition according to the invention can contain 10 to 85% by weight expandable graphite, in particular 20 to 50% by weight in relation to the entire composition. To ensure optimal workability in an injection-moulding unit, the compositions according to the invention are preferably as free from water as possible. Under the meaning of the present invention, this is understood to mean that the percentage of free water, which is not water of crystallization or intercalated in the pores of the solid, is less than 1% by weight, particularly less than 0.5% by weight. According to one development of the composition according to the invention, the thermoplastic polymer used herein is characterized by a softening point of 50 to 150'C, particularly 70 to 140'C. More advantageously, the thermoplastic polymer or the polymer mixture used according to the invention has a softening point of at least 50'C, more preferred of at least 60'C. Especially preferred is a softening point of maximally 150'C, advantageously of 140'C, more preferably of maximally 130'C. This is particularly advantageous since the softening point of these polymers is below the onset temperature of the expandable graphite. Additionally preferred is when the softening point of the thermoplastic polymer and the onset temperature of the expandable graphite are coordinated in such a manner that the softening point of the thermoplastic polymer is at least 10 0 C, especially at least 15'C or even at least 20'C above the onset temperature of the expandable graphite.

5 The contents of the thermoplastic polymer can vary in vast ranges and the composition can be adjusted based on the consistency desired. The contents can, for example, be 10 to 60% by weight, in particular 30 to 50% by weight, respectively with regard to the entire composition. The thermoplastic polymer can consist of a single polymer or of a mixture of different polymers. In such a mixture, polymers that are not thermoplastic can also be used as long as the overall mixture has thermoplastic characteristics. The thermoplastic polymer used according to the invention can be selected from a group comprising polyolefins such as polyethylene, in particular (PE-HD (HDPE), PE-LD (LDPE), PE-LLD (LLDPE), PE-HMW, PE-UHMW), polypropylene, also polyurethane, polyvinyl acetate, polyvinyl ether, polyvinyl propionate, polystyrene, natural or synthetic rubber, silicone, poly-(meth)acrylate and homo and copolymers based on (meth)acrylates, acrylonitrile, vinyl esters, vinyl ethers, vinyl chloride, and/or styrene as well as hybrid polymers preferably those based on polyethylene oxide and/or polypropylene oxide with dimethylsilyl end groups, polymethacrylic acid alkyl ester, polyacrylic acid alkyl ester, polymethacrylic acid aryl ester), polyacrylic acid aryl ester and/or copolymers thereof with n butyl acrylate, vinyl acetate and/or styrene, furthermore ethylene acrylic acid acrylate copolymers, ethylene acrylic acid maleic anhydride, ethylene butyl acrylic copolymers, ethylene butene copolymers, ethylene ethyl acetate copolymers, ethylene methacrylic acid estercopolymers, ethylene methacrylic acid copolymers, ethylene methyl acrylate copolymers or mixtures of these homo-, co-, or terpolymers. In a further configuration of the composition according to the invention, the proportion of inorganic filler is 0.1 to 50% by weight, in particular 2 to 30% by weight. Such filler content lends the composition improved stability without, however, increasing the viscosity of the composition upon melting that it loses its favorable injection-moulding qualities. Moreover, the addition of inorganic filler reduces the proportion of thermoplastic polymer, making the composition less expensive to manufacture. An additional advantage consists in the reduction of volumetric shrinkage during injection moulding owing to the addition of inorganic fillers in the amounts specified. In this manner, the dimensional accuracy of the manufactured moulded body is improved.

6 Within the framework of the present invention, theoretically all inorganic fillers can be used that are suitable for filling polymer compositions, in particular for filling thermoplastics. Preferably the inorganic filler selected is from the group comprising glass, in particular fiberglass, glass powder, (hollow) glass beads, and glass flakes, (quartz) sand, gypsum, fumed silica, bentonite, chalk, kaoline, rock flour, barite, and/or wollastonite as well as mixtures thereof. Other water-insoluble inorganic fillers can also be used. In addition to the fillers, the composition can also contain one or more additives in customary amounts, such as additives with a ceramifying effect, glass frits, fiberglass, ammoniumphosphate, zinc borate, kaoline, clay and/or betonite, flame-resistant additives with an ablative effect such as aluminum hydroxide, aluminum hydroxide trihydrate, boehmite (AIOOH), magnesium hydroxide, zinc borate and/or calcium sulfate, in particular flame resistant additives that are supplementary, intumescent, especially inorganic flame-resistant additives such as sodium borosilicate, encapsulate borosilicate. Some of these additives also simultaneously function as fillers. Additives can furthermore be used as stabilizers, pigments, fungicides and/or softeners. Among the stabilizers, in particular UV stabilizers or antioxidants, that can be used as additives within the framework of the invention are phosphites, phenols, sterically hindered phenols of high molecular weight, polyfunctional phenols, sulfur- and phosphor-containing phenols or amines. Non-reactive, fine, inorganic minerals are suitable as pigments. They can be powdered, precipitated, or surface-treated. Examples are chalk, coated chalk, powdered limestone, calcium-magnesium carbonate, aluminum oxide and -hydroxide, precipitated silicic acid, titanium dioxide, barium sulphate, sodium or aluminum silcate, zeolites, betonites or powdered minerals. The particle size should be between 1 to 200 pm, in particular between 3 to 50 pm. It must be ensured that materially there is no common clear delimitation between the usable fillers and pigments since chalk, for example, can be used as both filler as well as white pigment. Particularly preferred is the use of flame-retardant additives that are also designated as a fire protection agent. Present useable fire-protection agents are, for example, polybrominated diphenyl ethers (PentaBDE, OctaBDE, DeccaBDE), TBBPA, and HBCD, melamine, urea, 7 APP (ammoniumpolyphosphate), TCEP (Tris(clorethyl)phosphate), TCPP (Tris(clorpropyl)phosphate), TDCPP (Tris(dichlorisoproply)phosphate), TPP (triphenylphosphate), TEHP (Tri-(2-ehtylhexyl)phosphate), TKP (Trilresylphosphate), ITP ("isopropylated tirphenylphosphate") mono-, bus-, and tris)isopropylphenyl)phosphate of differing degrees of isopropylation, BDP (Bisphenol-A-bis(diphenylphosphate)), RDP (resorcinol bis (diphenyl phosphate)), ATH (aluminum hydroxide), MDH (magnesium hydroxide), ammonium sulfate ((NH4(2SO4) and -phosphate ((NH4(2P04), EDAP (ethylene diamine acid phosphate), GP (guanidine phosphate) or also mixtures thereof. An additional object of the present invention relates to an intumescent moulded body manufactured by injection moulding an intumescent injection moulding material according to the invention. To manufacture such a moulded body, it is necessary to proceed in such a manner that a composition according to the invention is first produced as described above as a solid mixture. This composition is then processed on a conventional injection moulding machine and filled into an injection mould that has already been set up. After the moulded bodies have cooled or solidified, they can be removed from the injection mould. Alternatively, the composition can also first be produced in the injection moulding machine, the melting and mixing taking place in an extruder of the injection moulding machine. A composition produced in this manner can either be directly further processed into moulded bodies in an injection moulding machine or can first be extruded and granulated thereafter. The pellets that are obtained can then be used at a later time for manufacturing moulded bodies according to the invention. The subject matter of the present invention is moreover a ventilation grate for preventing fire and smoke from leaving one room and entering another during a fire, the ventilation grate being composed of a multitude of intersecting grate ribs and consists of a composition that contains a binding agent and an active agent that foams at least in a fire. The ventilation grate is advantageously an intumescent moulded body that is manufactured by injection moulding a composition according to the invention.

8 Ventilation grates within a building represent a danger during a fire because fire and smoke can easily travel through them from one room to the next. To address this problem, document DE 195 24 766 Al proposed a self-closing flap the valve flaps of which are coated with an intumescent material to increase heat resistance in the event of a fire. The fire resistance of such air flaps is, however, not very satisfactory since the intumescent coating is relatively thin and the air flap itself is made of metal, which thereby permits thermal bridges to be formed easily. Furthermore, ventilation grates are known from the prior art that consist entirely of a material that has intumescent properties. The Helios Ventilatoren GmbH & Co company sells a ventilating brick that contains an organic material that foams in the event of a fire. Such ventilating bricks are manufactured using a casting process in which the components of the brick are first mixed together and thereafter cast into the desired shape. Since such castable compositions usually have high viscosities owing to the proportion of organic intumescent materials, the shaping possibilities are very limited for bricks manufactured therewith. Particularly the manufacture of more delicate structures of sufficient quality is not possible with such compositions. Furthermore, the curing times of the composition used is found to be insufficient since it has a disadvantageous effect on the length of cycle with a casting mould during production. The problem addressed by this invention thus consists in creating a ventilation grate that is self-closing by means of intumescence, that can be manufactured more easily, and that can be realized having more complex structures. This problem is solved by the use of exfoliated graphite and/or a siliceous material in combination with a thermoplastic polymer binding agent. One first subject matter of the present invention thus concerns a ventilation grate for preventing fire and smoke from moving from one room to another during a fire, the ventilation grate being composed of a multiplicity of intersecting grate ribs and furthermore of a composition that contains at least one active agent that foams in the event of fire and a binding agent, said active agent that foams in the event of a fire being selected from exfoliated graphite and/or expandable siliceous material, with the binding agent furthermore being a thermoplastic polymer.

9 The use of a thermoplastic polymer makes it possible for the composition containing exfoliated graphite and/or an expanding silicate material to be placed into the mould by means of injection moulding in the shape of the ventilation grate according to the invention. The use of an injection-moulding method makes shorter production times possible and the manufacture of ventilation grates with more delicate structures is also possible. Such structures that are more delicate are, for example, delicate grate ribs or, in order to combine a plurality of ventilation grates, tongues and grooves therein. They can be moulded as a dovetail tongue and groove, for example. In the event of a fire, the exfoliated graphite or the expanding silicate material in the material of the ventilation grate expands because of the effects of the heat or, in other words, it increases the volume of the grate ribs. In this manner, the grate passages become increasingly narrowed at the location of the fire until virtually no air and/or no smoke can pass through the grate. During this process, the thermoplastic polymer used as a binding agent ensures the required cohesion since it is transferred in its plastic state through the heat of the fire. Since the material of the grate can withstand high temperatures for a longer period of time, more effective fire protection is achieved. In contrast, the standard ventilation grate behaves like a metal grate. An additional advantage of the self-closing ventilation grate according to the invention consists in the fact that light soiling caused by dust, grease or the like practically does not negatively affect the function of the grate. Furthermore, no moving parts need be provided that could possibly fail in case of an emergency. The ventilation grates according to the invention can, for example, be manufactured to have the strength of a brick and can be integrated into a wall immediately after being produced or can also later be placed in a purpose-built opening therefor. Cement mortar or a cement adhesive can be used, for example, for joining with the masonry or a concrete wall. In an advantageous configuration of the ventilation grate according to the invention, the composition contains no organic, intumescing materials.

10 In a development of the present invention, the ventilation grate can have an integral cladding and be configured as a square or cylindrical body. The integral cladding covers the grate on all lateral faces so that only the inlet and outlet surfaces defined by the grate ribs remain unobstructed. The ventilation grate according to the invention can furthermore have at least one coupling device with which the ventilation grate can be connected to further ventilation grates like a module, the coupling device preferably being positioned on the exterior of the cladding. With the one construction type of ventilation grate, differently dimensioned vents can be created in building walls given that, for example, two or four ventilation grates according to the invention are joined together to form one grate. A tongue and groove joint is a particularly well suited type of connection between a plurality of ventilation grates. In this instance, the connecting device accordingly consists in a groove or a tongue that are configured in such a manner that correspond to one another. It is also possible that the ventilation grate according to the invention has only grooves and the tongues, as a separate component, are placed in the respective grooves to connect a plurality of grates. These separate tongues preferably consist of the same composition as the ventilation grate. To obtain a particularly solid interconnection between a plurality of ventilation grates, the groove can have an undercut and the tongue a shape that corresponds thereto. In particular, this can be designed in the form of a dovetail tongue and groove. Prior to installation, the ventilation grates can thus be pre-assembled by being slid together at the desired location. The undercuts prevent the differing grate modules from falling apart during installation. The tongue and groove joint can be fixed with an adhesive. In a particularly advantageous manner, both tongue and groove taper along their longitudinal direction. A run-up surface is formed in this and the ventilation grates to be coupled to one another can only be pushed so far into one another that the grate ribs are positioned so as to be flush with one another. Precise installation at the construction site is hereby made considerably easier.

11 The connecting device used extends preferably along the longitudinal extension of the cladding and particularly extends over the entire longitudinal extension, thus ending with the edge of the cladding. According to a particularly preferred embodiment of the ventilation grate according to the invention, said ventilation grate has four connecting devices that are arranged such that the ventilation grate can be connected in a modular manner with four additional ventilation grates. Such an embodiment can be so configured, for example, that the ventilation grate has a cladding with a rectangular or square cross section and each of the rectangular or square cladding surfaces has a connecting device. If tongue and groove connections are used in the connecting devices in the previously described embodiment, it is furthermore preferred that two of the four connecting devices be configured as grooves and two as tongues. Especially preferred is that they are arranged on the cladding of the air vent in such a manner that the two grooves are provided on adjacent cladding surfaces and two tongues are likewise provided on two adjacent cladding surfaces. Such a configuration allows for any number of air vents according to the invention to be joined together in a modular fashion. In addition or alternatively to the previously-described connection devices configured on the air vent, the air vent can also be associated with at least one coupling means with which the air vent can be connected to further air vents in a modular fashion. Elastic tongues and/or clamps, for example, are candidates for such coupling means. Within the context of the present invention, it can be provided that the grate ribs of an air vent have at least two different strengths and when forming the grate are arranged in such a manner that one or more stronger grate ribs follow a plurality of adjacent, weaker grate ribs. In this manner, stabilizing stronger grate ribs can be provided in certain intervals so as to increase the overall stability of the grate. The stronger ribs can, for example, have a strength that is 1.5 times, preferably at least 2 times, more preferably at least 2.5 times or even at least 5 or 6 times the strength of the weaker grate ribs. It is also possible to use a plurality of stronger ribs of varying thicknesses.

12 This arrangement of stronger and weaker grate ribs can be provided in a crossed grate structure for both or optionally for a group of crossed grate ribs. If both groups of crossed grate ribs have this configuration, the intervals in which the stronger grate ribs are used can be the same or different. Ventilation grates according to the invention can, owing to the favorable injection moulding qualities of the composition used, theoretically have any possible shape and arrangement of grate ribs. In this manner, the grate ribs form at least in sections a crossed grate structure or honeycomb structure. According to a particularly preferred embodiment of the ventilation grate according to the invention, said ventilation grate can be manufactured by or through an injection moulding process. A further object of the present invention relates to a method for manufacturing a ventilation grate to prevent fire and smoke from passing from one room to another in the event of a fire, comprising the following steps: - preparing a mould, in particular an injection mould, having a plurality of cavities for forming intersecting grate ribs of the ventilation grate; - introducing a fluid composition into the mould, preferably in the injection moulding, the composition containing a material that foams in the event of a fire, which material contains exfoliated graphite and/or an expandable silicate material and a thermoplastic polymer; - curing the composition to form a ventilation grate; - removing the ventilation grate from the mould. The use of an injection moulding process is especially preferred owing to the above mentioned advantages. In a development of the method according to the invention, prior to being introduced into the mould, the composition, which contains a material that foams in the event of a fire and the thermoplastic polymer, is produced in separate work step in which the thermoplastic polymer is melted and the material that foams in the event of a fire as well as auxiliary agents if desired and mixed with the melt. In another preferred manner, the melting and mixing can be affected in one extruder. A composition produced in this manner can either be processed 13 further immediately in an injection moulding machine or first extruded and granulated. The pellets obtained can then be used later for the production of ventilation grates according to the invention. The present invention is described in greater detail using the embodiments shown in figures 1 to 3, which show in Fig. 1 a ventilation grate according to the invention in the plan view, Fig. 2 a ventilation grate according to the invention viewed laterally and Fig. 3 a ventilation grate according to the invention in a three-dimensional representation. Figure 1 shows a ventilation grate 1 according to the invention. The ventilation grate 1 consists of a composition of 40% by weight exfoliated graphite, 40% by weight HDPE as thermoplastic polymer as well as 20% by weight chalk as filler. The thermoplastic polymer was initially melted in an extruder and the exfoliated graphite as well as chalk intermixed after which the composition was granulated. Thereafter, the ventilation grate 1 was manufactured from these pellets in an injection moulding machine. The ventilation grate 1 has a square cross-section and has a plurality of horizontal and vertical grate ribs 2, 3, 4, 5 that form grate openings 6 as air passages and that correspond to the grate pattern. The horizontal and vertical grate ribs 2, 3, 4, 5 each have thinner grate ribs 2, 4 and thicker, stabilizing grate ribs 3, 5. The grate ribs 2, 3, 4, 5 are enclosed in a circumferential cladding 7 on the outside of which are four connecting elements 8, 9, 10, 11 of which two on adjacent external sides are configured as tongues 8, 11 and the other two are configured as grooves 9, 10. The grooves 9, 10 have undercuts 12, 13 with which the tongues 8, 11 have corresponding shapes 14, 15. Figures 2 and 3 show the ventilation grate 1 depicted in figure 1 from a lateral figure (figure 2) and in a three-dimensional view seen obliquely from above (figure 3). It can be seen in these representations that the groove 9 tapers along its longitudinal direction to the left. In the view shown in figure 2, the grate ribs 4 running on the inside of the ventilation grate 1 are covered by the cladding 7 owing to the particular perspective, yet are indicated by dotted lines.

14 The ventilation grate 1 depicted in the figures is introduced into, for example, a concrete wall. In a fire, the intumescent active ingredient, such as exfoliated graphite, that is contained in the ventilation grate 1 expands owing to the effects of heat. Since the cladding 7 of the ventilation grate 1 is in direct contact with the concrete wall, expansion is not possible in this direction. Accordingly, the volumetric expansion must occur practically only within the grate 1. The expansion of the grate ribs 2, 3, 4, 5 as well as of the cladding 7 causes the grate openings 6 to close in little time and no smoke or combustion gases can pass through the ventilation grate. The spreading of the fire to the adjacent rooms by means of hot combustion gases is thereby effectively prevented. Reference signs 1 Ventilation grate 2 Grate rib 3 Grate rib 4 Grate rib 5 Grate rib 6 Grate opening 7 Cladding 8 Tongue (connecting device) 9 Groove (connecting device) 10 Groove (connecting device) 11 Tongue (connecting device) 12 Undercut 13 Undercut 14 Corresponding shape 15 Corresponding shape

Claims

1. Intumescent composition containing a polymer binding agent, expandable graphite (exfoliated graphite), and at least one inorganic filler, characterized in that the composition can be injection moulded and the polymeric binding agent has a thermoplastic polymer with a softening point of 160'C or less.

2. Composition as specified in claim 1, characterized in that the composition is as free of water as possible.

3. Composition as specified in claim 1 or claim 2, characterized in that the thermoplastic polymer has a softening point of 50 to 150'C, in particular of 70 to 140'C.

4. Composition as specified in one of the preceding claims, characterized in that the softening point of the thermoplastic polymer is at least 10 0 C, especially at least 15'C, above the onset temperature of the expandable graphite.

5. Composition as specified in one of the preceding claims, characterized in that the thermoplastic polymer content is 10 to 60% by weight, particularly 30 to 50% by weight.

6. Composition as specified in one of the preceding claims, characterized in that the thermoplastic polymer is selected from a group comprising polyolefins such as polyethylene, in particular (PE-HD (HDPE), PE-LD (LDPE), PE-LLD (LLDPE), PE HMW, PE-UHMW), polypropylene, also polyurethane, polyvinyl acetate, polyvinyl ether, polyvinyl propionate, polystyrene, natural or synthetic rubber, silicone, poly (meth)acrylate and homo and copolymers based on (meth)acrylates, acrylonitrile, vinyl esters, vinyl ethers, vinyl chloride, and/or styrene as well as hybrid polymers preferably those based on polyethylene oxide and/or polypropylene oxide with dimethylsilyl end groups, polymethacrylic acid alkyl ester, polyacrylic acid alkyl ester, polymethacrylic acid aryl ester), polyacrylic acid aryl ester and/or copolymers thereof with n-butyl acrylate, vinyl acetate and/or styrene, furthermore ethylene acrylic acid acrylate copolymers, ethylene acrylic acid maleic anhydride, ethylene butyl acrylic copolymers, ethylene butene copolymers, ethylene ethyl acetate copolymers, ethylene methacrylic 16 acid estercopolymers, ethylene methacrylic acid copolymers, ethylene methyl acrylate copolymers or mixtures of these homo-, co-, or terpolymers.

7. Composition as specified in one of the preceding claims, characterized in that the proportion of expandable graphite is 10 to 85% by weight, in particular 20 to 50% by weight.

8. Composition as specified in one of the preceding claims, characterized in that the proportion of inorganic filler is 0.1 to 50% by weight, in particular 2 to 30% by weight.

9. Composition as specified in one of the preceding claims, characterized in that the inorganic filler is selected from the group comprising glass, in particular fiberglass, glass powder, (hollow) glass beads, and glass flakes, (quartz) sand, gypsum, fumed silica, bentonite, chalk, kaoline, rock flour, barite, and/or wollastonite as well as mixtures thereof.

10. Composition as specified in one of the preceding claims, characterized in that the composition contains a flame-retardant additive.

11. Composition as specified in claim 10, characterized in that the flame-retardant additive is selected from the group comprising polybrominated diphenyl ethers (pentaBDE, octaBDE, deccaBDE), TBBPA, and HBCD, melamine, urea, APP (ammonium polyphosphate), TCEP (Tris(clorethyl)phosphate), TCPP (Tris(clorpropyl)phosphate), TDCPP (Tris(dichlorisoproply)phosphate), TPP (triphenylphosphate), TEHP (Tri-(2 ehtylhexyl)phosphate), TKP (Trilresylphosphate), ITP ("isopropylated tirphenylphosphate") mono-, bus-, and tris)isopropylphenyl)phosphate of differing degrees of isopropylation, RDP (resorcinol bis (diphenyl phosphate)), BDP (Bisphenol A-bis(diphenylphosphate)), ATH (aluminum hydroxide), MDH (magnesium hydroxide), ammonium sulfate ((NH4(2SO4) and -phosphate ((NH4(2P04), EDAP (ethylene diamine acid phosphate), GP (guanidine phosphate) or also mixtures thereof.

12. Composition as specified in one of the preceding claims, characterized in that the composition contains one or more additives that are particularly selected from the additives with a ceramifying effect, flame-resistant additives with an ablative effect, 17 supplementary intumescent fire-resistant additives, stabilizers, pigments, softeners and/or fungicides.

13. Intumescent moulded body, characterized in that the moulded body is produced by injection moulding a composition according to one of the previous claims 1 to 12.

14. Intumescent granules, characterized in that the granules are produced by injection moulding a composition according to one of the previous claims 1 to 12 followed by subsequent granulating or through granulation of a moulded body as specified in claim 3.

15. Ventilation grate (1) for preventing the passage of fire and smoke from one room to another during a fire, the ventilation grate being constructed from a plurality of intersecting grate ribs (2, 3, 4, 5) and consisting of a composition that contains a binding agent and an active agent that foams at least in the event of a fire, in particular as a moulded body according to claim 13, characterized in that the active ingredient that foams in the event of a fire is composed of an exfoliated graphite and/or expandable silicate material and the binding agent is a thermoplastic polymer.

16. Ventilation grate according to claim 15, characterized in that the expandable silicate material is selected from vermiculite, sodium and/or potassium silicate, in particular sodium and/or potassium water glass.

17. Ventilation grate according to claim 15 or 16, characterized in that that composition contains 10 to 85% by weight of the active ingredient that foams in the event of a fire, in particular 20 to 50% by weight as relates to the entire composition. 18

18. Ventilation grate according to one of the preceding claims, characterized in that the composition contains 10 to 60% by weight of the thermoplastic polymer, in particular 30 to 50% by weight as relates to the entire composition.

19. Ventilation grate according to one of the preceding claims, characterized in that the composition contains one or more auxiliary agents that are particularly selected from the additives with a ceramifying effect, flame-resistant additives with an ablative effect, supplementary intumescent fire-resistant additives, stabilizers, pigments, fungicides, softeners, and/or fillers.

20. Ventilation grate according to one of the preceding claims, characterized in that the ventilation grate has an integral cladding (7) and is configured as a square or cylindrical body.

21. Ventilation grate according to one of the preceding claims, characterized in that the ventilation grate has at least one connecting device (8, 9, 10, 11) with which the ventilation grate can be connected to additional ventilation grates in a modular fashion, the connecting device (8, 9, 10, 11) being preferably arranged on the exterior of the cladding (7).

22. Ventilation grate according to claim 21, characterized in that the connecting device (8, 9, 10, 11) is agroove (9, 10) or a tongue (8, 11).

23. Ventilation grate according to claim 22, characterized in that the groove (9, 10) has an undercut (12, 13) and the tongue (8, 11) has a shape (14, 15) that corresponds thereto.

24. Ventilation grate according to claim 21 or 22, characterized in that the groove (9, 10) and tongue (8, 11) taper along their longitudinal direction.

25. Ventilation grate according to one of claims 21 to 24, characterized in that the connecting device (8, 9, 10, 11) extends along the longitudinal extension of the cladding (7). 19

26. Ventilation grate according to one of claims 21 to 25, characterized in that the ventilation grate has four connecting devices (8, 9, 10, 11) that are arranged in a manner that the air gate can be connected with four additional ventilation grates in a modular fashion.

27. Ventilation grate according to one of the preceding claims, characterized in that the ventilation grate is associated with at least one coupling means with which the ventilation grate can be connected to additional ventilation grates.

28. Ventilation grate according to claim 27, characterized in that the coupling means are configured as tongue and/or as clamps.

29. Ventilation grate according to one of the preceding claims, characterized in that the ventilation grate ribs (2, 3, 4, 5) of a ventilation grate have two different strengths and are arranged to form the grate in such a manner that one or a plurality of thicker grate ribs (3, 5) follow after a plurality of adjacent thinner ribs (2, 4).

30. Ventilation grate according to one of the preceding claims, characterized in that the ventilation grate ribs (2, 3, 4, 5) form a crossed grate structure or honeycomb structure at least in sections.

31. Ventilation grate according to one of the preceding claims, characterized in that the ventilation grate can be manufactured by injection moulding.

32. Method of manufacturing a ventilation grate (1) to prevent fire and smoke from passing from one room to the next in a fire, comprising the following steps: - preparing a mould, in particular an injection mould, with a plurality of cavities for forming intersecting grate ribs (2, 3, 4, 5) of the ventilation grate; - introducing a fluid composition into the mould, preferably in the injection moulding, the composition containing a material that foams in the event of a fire, which material contains exfoliated graphite and/or an expandable silicate material and a thermoplastic polymer; - curing the composition to form a ventilation grate; - removing the ventilation grate from the mould. 20

33. Method according to claim 32, characterized in that the composition composed of the material that foams in a fire and the thermoplastic polymer is produced in a separate work step prior to introduction into the mould, the thermoplastic polymer being melted and the material that foams in a fire as well as auxiliary agents if desired are intermixed with the melt.

34. Method as specified in claim 33, characterized in that the melting and intermixing is performed in an extruder.