AU5932899A

AU5932899A - Reactive two-component polyurethane foam composition and a fire-protective sealing method

Info

Publication number: AU5932899A
Application number: AU59328/99A
Authority: AU
Inventors: Christian Forg; Franz Heimpel; Herbert Munzenberger; Stefan Rump
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 1998-12-24
Filing date: 1999-11-10
Publication date: 2000-06-29
Anticipated expiration: 2019-11-10
Also published as: AU758313B2; EP1013706A1; DE19860339C2; DE19860339A1; PL337395A1

Description

-1-

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name of Applicant/s: Actual Inventor/s: Address for Service: Invention Title: Hilti Aktiengesellschaft Herbert Munzenberger and Franz Heimpel and Stefan Rump and Christian Forg BALDWIN SHELSTON WATERS MARGARET STREET SYDNEY NSW 2000 'REACTIVE TWO-COMPONENT POLYURETHANE FOAM COMPOSITION AND A FIRE-PROTECTIVE SEALING METHOD' The following statement is a full description of this invention, including the best method of performing it known to me/us:- File: 25508AUP00 la REACTIVE TWO-COMPONENT POLYURETHANE FOAM COMPOSITION AND A FIRE-PROTECTIVE SEALING METHOD Field of Invention The present invention relates to a reactive two- 5 component polyurethane foam composition for producing heat- and flame-resistant foams, with a polyol component and a polyisocyanate component and a method for the fireprotective sealing of openings and/or ducts in walls and/or ceilings of buildings using these polyurethane foams.

Background Information and Prior Art In accordance with the building regulations of the individual German States, there are special fire protection guidelines for public and larger buildings. These include measures, which are required for limiting the spread of fires that may occur. The spread of fires is prevented, for example, owing to the fact that the building is divided into special fire sections. The walls and ceilings of the buildings, which form the boundaries of the fire section, are tested in accordance with the DIN 4102 Standard by the Institut fur Bautechnik und Massivbau, Braunschweig (IBMB) or by a different State Institute 2 (such as a Material Testing Institute) and licensed by the Deutschen Institut fir Bautechnik, Berlin (DIBT). Openings and break-throughs in these walls and ceilings must not have a negative effect on these walls and ceilings. For this reason, openings (doors, windows) and break-throughs or ducts for pipes, cables or cable routes must be closed off in such a manner, that they do not affect the original fire resistance of the wall or the ceiling. This whole system is tested by a State Institute ofor its behavior in the event of a fire (testing of a building 10 component). After a successful test, the Building Inspectors ~license the tested fire-protection article in the defined fire wall or fire ceiling with a detailed implementation by the DIBT.

Parallel to this the building material, which oooee S• describes the proposed fire protection system with respect to oooe° its combustion behavior, is licensed. Fire-protection products ["may be offered for sale, sold and installed only if the building S"material and the building component have been tested.

Some fire-protection articles, which evidently are suitable for effectively sealing off pipe and cable ducts with the formation of the aforementioned fire sections, are already known on the market. However, these facilities are not always easily installed. Frequently, these openings are not readily 3 accessible, for example, when they are in corners or can be reached only from one side, behind a suspended ceiling or below the ceiling of a roof. The installation of the fire-protection article is very labor intensive here due to the mounting of frameworks or the manufacturing of openings or of the articles.

Furthermore, one-component polyurethane foam compositions are known under the name of "fire protection foam".

They have only been tested as building materials, but only in very few cases also as a building component. These materials are suitable only for very limited areas of applications, primarily for filling narrow and deep gaps with foam. In the event of a fire, the wall of the gap of a material, such as concrete, withdraws so much heat from the flame, that the one- S• component foam introduced withstands the fire for a certain i o period of time. However, in the case of larger openings, such as cable ducts or pipe leadthroughs, these systems fail completely.

Moreover, the flame-protective properties of the foam depend very much on the surrounding conditions. At low room air and underground temperatures and, with that, at a low relative humidity, these one-component polyurethane foam compositions will not react completely for days and partially collapse. In 4 the event of a fire, the openings and gaps formed offer an ideal place for the fire to cross into the next fire section of the building, which is believed to be safe.

At high temperatures, on the other hand, the curing of the outer foam zone is greatly accelerated. At the same time, however, the entry of heat and water into the center of the foam is hindered by the closed cell nature of the foam and the therefrom resulting insulating effect. On the one hand thus, "heat and moisture cannot reach of the center of the foam. On the other, the reaction at the surface is already completed, so that the capillaries are closed off and heat and moisture can no longer be transported into the center. The centrally located portion of the foam can therefore no longer react completely and S"collapses after some time. However, this effect cannot be eoo recognized from the outside. The user sees a smooth, clean foam surface, which simulates the best fire properties but, in the case of a fire, is practically ineffective.

The DE-A-42 34 374 already discloses a fire-protection closing-off material for cables and other supply lines, which are combustible or at risk in a fire. This material consists of a mixture, which is present in the form of two components, which react when mixed to form a foam, which belongs to the family of 5 polyurethanes and is difficult to ignite and adheres outstandingly to mineral substrates and to metal. Moreover, the polyurethane foam body is formed using a polyalcohol, namely a polyether polyol as binder component and an isocyanate component, namely a diisocyanate. The polyol component preferably contains intumescing additives and the components may contain known flame retardants. Moreover, the foam composition *of the bulkhead material can be introduced directly into the openings of the building component from multicomponent 10 cartridges or by means of metering pumps. However, it has turned out that this fire-protection bulkhead material based on polyurethane foams must be applied using expensive cartridges or metering pumps and results in a foam, which is not sufficiently stable. This makes it difficult or impossible to use such materials for openings, which are not readily accessible, such as overhead openings.

The object of GB-A1 404 822 are rigid polyisocyanurate foams with excellent dimensional stability at high temperatures and a high fire resistance. As an essential component, these polyisocyanurate foams contain intumescing materials, such as expanding graphite or vermiculite, that is, organic or inorganic solids which, when heated to a temperature of about 150 0

C,

increase in their volume at least about threefold. It has 6 turned out that these intumescing materials are harmful to the flame resistance aimed for, if such foams are to be applied in situ for the fire-protective sealing of openings and/or ducts in walls and/or ceilings of buildings. Due to their forceful expansion, the components, intumescing under high pressure, destroy the connecting and insulating carbon crust. The latter is broken off and the heat of the flame attacks previously protected foam layers.

S. The US patent 4,452,829 describes cross-linked 10 polyisocyanurate compositions, which can be sprayed onto a surface and rapidly foam and cross link there with the formation S" of a rigid or flexible composition, which provides a heatresistant flame-resistant coating. The sprayable •polyisocyanurate composition is prepared by mixing and reacting two components A and B, one of which is a methylenebis(diphenylisocyanate) of low functionality and a polyether triol and the other a polyether triol and optionally a blowing agent, as well as a halogenated hydrocarbon, such as chlorofluoromethane, as well as a catalyst for the reaction of the polyisocyanate with the polyol. This polyisocyanurate foam composition, which can be sprayed on, does not satisfy either with respect to the fire protection properties or with respect to the stability during use.

7 The DE-C-29 30 881 discloses a method for producing flame-resistant, urethane modified polyisocyanurate foams, which are formed by reacting an organic polyisocyanate with a low molecular weight diol in the presents of an isocyanate trimerizing catalyst. The components, used to form this foam, may additionally contain a blowing agent, foam stabilizers as well as fire-resistant fibrous materials or inorganic fillers or also phosphorus compounds or inorganic flame retarders, such as S• antimony oxide. These foams are produced in a mold by mixing 10 the components and foaming and, because of their improved flame resistance and thermal insulation properties, can be used as "thermally insulating materials in construction. Because of their initial low strengths, these polyisocyanurate foams are also not suitable for the in situ fire protective sealing off of openings and/or ducts in walls and/or ceilings of buildings and, instead, are used as pre-fabricated components. However, the manufacture of such molded parts is expensive and such parts do not make it possible to close off the irregular surfaces of openings in masonry and of cable coatings hermetically.

Moreover, adequate adhesion to the substrates is not attained.

8 Object of the Invention The object, on which the present invention is based, therefore consists of providing a polyurethane foam composition, which can be used for producing heat-resistant and flameresistant foams, especially for the fire protective sealing of openings and/or of ducts in walls and/or ceilings of buildings and ensures a rapid and reliable installation with good accessibility on many substrates typical of construction.

Summary of the Invention .9° 10 This objective is now accomplished by the reactive two-component polyurethane foam composition of claim 1. The dependent claims relate to preferred embodiments of the object of the invention and to a method for the fire protective sealing using these two-component polyurethane foam compositions.

o* 15 The object of the invention therefore is a reactive 9**999 two-component polyurethane foam composition for producing heatresistant and flame-resistant foams, with a polyol component (A) and a polyisocyanate component characterized in that the polyol component contains Al) 39.5 to 92.2% by weight of at least one polyester alcohol with a hydroxyl number ranging from 130 to 550 and a viscosity of 4,000 to 10,000 mPas 9 A2) 0.6 to 4.0% by weight of one or more catalysts for the reaction between the polyol and the polyisocyanate, A3) 0.2 to 1.4% by weight of at least one chemical blowing agent, A4) 6.5 to 32.5% by weight of at least one physical blowing agent and 0.5 to 22.5% by weight of the red phosphorus; the polyisocyanate component contains Bl) 78.9 to 99.9% by weight of at least one organic 10 polyisocyanate with an average isocyanate functionality of more than 2.2 and B2) 0.1 to 21.1% by weight of at least one physical blowing agent; the ratio of isocyanate groups of the polyisocyanate component 15 to the hydroxyl groups of the polyol component is between 1.4 and 3.0 to 1; and the foam composition is free of solid intumescing materials, which increase their volume when heated.

It is an essential characteristic of the inventive polyurethane foam composition that the two separate components, namely the polyol component and the polyisocyanate component contain all the constituents which, within the scope of an exothermic reaction, which proceeds without problems even at 10 underground temperatures of 50C, provide a three-dimensional, cross-linked polyurethane foam, which is distinguished by surprisingly advantageous fire protection properties. Due to the presence of a physical blowing agent in both components, it becomes possible, on the one hand, to expel all the constituents of the polyurethane foam composition under the pressure of the blowing agent from the pressure vessels, in which they are contained, so that only a hose BUPPly line with an outlet valve is required, which enables the foam to be delivered readily even to openings, which are difficult to reach. on the other hand, these physical blowing agents bring about additional foaming of the foam with escape of the blowing agent, which leads to a higher initial strength of the foam, so that this foam composition can readily be introduced into larger, even overhead ceiling openings, without formwork or the like being required.

*sees: 0 0600 **so Accordingly, when the inventive, reactive twocomponent polyurethane foam composition is used even when access is available only on one side, it is not necessary to sheathe the opening or to adapt the geometry of the opening to the fire protection material or the fire protection material to the shape of the opening. After curing, finishing work by cutting, sawing or the like can be carried out quickly and easily, so that newly 11 formed openings of removed cables or pipes can be closed off once again quickly and easily.

Due to the use of the selected polyester alcohol and the red phosphorus in the polyol component a high fire protection is assured, which is better than that achieved with the materials of the DE-A-32 34 374 and GB-B-I 404 822.

It is a significant point of view of the invention *that the polyurethane composition is free of added, solid, S"intumescing materials, the volume of which increases upon *ee. e 10 heating, such as expanding graphite, vermiculite or similar materials having a layered structure, which expand when heated and increase their volume at least threefold. It has turned out S" that the presence of such intumescent materials is disadvantageous, since the matrix formed by these means is too b eel 15 rigid and has too little strength, so that, in the event of a o fire, it breaks open. As a result, there is a rapid loss of .ooo insulating properties and a rapid advance of the depolymerization zone in the foamed material.

In contrast to this, the inventive two-component polyurethane foam composition provides a polyurethane foam, which optimally meets the requirements of the DIN 4102 Standard, 12 sections 5, 9, 11 and 12 in preventive structural fire protection.

As polyol component the inventive, two-component polyurethane foam composition preferably contains, as polyester alcohol an aromatic polyester alcohol with a hydroxyl number of 130 to 550, like the commercially obtainable polyester alcohol Terol 196, with a hydroxyl functionality of 2, an acid number of about 3 and a hydroxyl of about 178.

As catalyst preferably a mixture of catalysts is 10 used, which catalyze the reaction of the polyol with the polyisocyanate with formation of polyisocyanurate groups (trimerization catalyst) and optionally the formation of polyurethane groups and/or polyurea groups. In this connection,

S

the presence of a trimerization catalyst is necessary for the formation of a high proportion of isocyanurate groups-containing polyurethane foam for achieving the high fire resistance values.

Such catalysts, which catalyze the trimerization of isocyanates with formation of isocyanurate groups, are known to those skilled in the art. They are, preferably, metal salts of organic and/or inorganic acids, such as alkali metal salts or alkaline earth metal salts of carboxylic acids, such as sodium acetate, potassium acetate, potassium adipate, sodium benzoate, 13 potassium octoate or also tin salts, such as tin octoate or lead octoate, or aliphatic and aromatic amines, preferably tertiary amines, such as 2,4,6-tris(dimethylaminomethyl)-phenol, triethylamine, N-ethylmorpholine, N-methylmorpholine, tetramethyliminobispropylamine and the like. Such trimerization catalysts are described, for example, in the British patent 1,404,822 and the US patent 4,880,848.

Aside from the trimerization catalyst, preferred pursuant to the invention, the catalyst, used in the polyol 10 component may contain a catalyst, which reacts with the polyisocyanate group with formation of polyurethane groups and/or polyurea groups. Catalysts of this type are amines, such as tetramethyliminobispropylamine, dimethylcyclohexylamine, which are obtainable commercially under the name of catalyst LB or Polycat.

Preferably, a catalyst mixture is used, which contains at least one trimerization catalyst and optionally one or more catalysts for forming polyurethane groups and/or polyurea groups.

As component the polyol component of the inventive polyurethane foam composition contains a chemical 14 blowing agent, that is, a substance which reacts with one or more of the components of the polyol component or of the polyisocyanate component especially with the polyisocyanate, which releases gas during this reaction. A preferred chemical blowing agent is water, which releases carbon dioxide upon reaction with the polyisocyanate and thus causes foaming of the reaction products formed.

The polyol component as well as the polyisocyanate component each necessarily contains a physical blowing 10 agent, that is, a substance with a relatively low boiling point, which is lower than 170°C, preferably lower than 75 0 C and especially lower than 0 C. Since the overall reaction of the polyol component with the polyisocyanate component which takes place, is strongly exothermic, the boiling point of 15 the physical blowing agent is exceeded during this reaction, so that the blowing agent evaporates and foams the whole system.

Pursuant to the invention, a physical blowing agent with a boiling point below 0 C is preferably used because, with the help of this blowing agent, the two components of the claimed polyurethane foam composition, which preferably are filled into separate pressure tanks, can be driven out of these pressure containers and additional foaming of the material is brought 15 about, so that a very high expansion pressure of the foam, which is formed, is generated and, during the application, presses the foam into all the crevices of the opening that is to be treated, the foam adapting itself intimately to the surrounding material.

At the same time, the presence of the evaporating physical blowing agent brings about a higher stability of the foam that is forming, so that the latter can also be brought easily even into overhead areas or areas which are not readily accessible.

Pursuant to the invention, fluorinated blowing agents, 10 such as 1,1,1,2-tetrafluoroethane (blowing agent 134a) and/or 1,1,1,2,3,3,3-tetrafluoropropane (blowing agent 227) are preferably used as physical blowing agents. Pursuant to the invention, it is also possible to use a mixture, selected from fluorine-containing blowing agents of the type given above, and propane, butane and/or methyl ether as physical blowing agent.

The physical blowing agents, present in the polyol component (A) and the polyisocyanate component may be the same or different.

As an essential component, the polyol component of the inventive polyurethane foam composition contains red phosphorus as component which preferably is used in a 16 powdery or particulate form and is coated or microencapsulated, for example, by being coated by a melamine resin.

As already stated above, the polyol component of the inventive polyurethane foam composition contains at least one polyester alcohol. However, it has proven to be advantageous to use a mixture of polyols with a gradation of reactivities. Accordingly, the polyol component preferably contains, as additional component A6), 0 to 1.9% by weight of a further hydrocarbon, which reacts with the polyol component and 10 has a hydroxyl number ranging from 900 to 2,000 and a viscosity of 1,000 to 5,000 mPas, preferably an aliphatic diol and especially 1,4-dihydroxybutane and/or glycerol. These highly reactive polyols, with a hydroxyl number of 900 to 2,000, function as the spark for a larger group of moderately reactive polyols, which may be present as an additional component A7) in an amount of 0 to 4.5% by weight. The latter comprises polyether alcohols with a hydroxyl number ranging from 600 to 1,200 and a viscosity of 4,000 to 10,000 mPas. These moderately reactive polyols, the reaction of which is prodded by the highly reactive polyols of the aforementioned type A6), in turn initiate the reaction of the quantitatively largest group of polyester alcohols Al) with a hydroxyl number ranging from 170 to 550.

17 By using such a combination of an aromatic polyester alcohol as main component and a diol and one or more polyether alcohols of the defined type as subsidiary components, the claimed polyurethane foam composition yields a product with properties, which are improved even further with respect to the practical application and the strength and fire protection properties attained.

For improving the foam properties even further, it is possible to add 0 to 1.0% by weight of at least one foam 10 stabilizer, such as an organic silicone foam stabilizer, a surface-active siloxane and/or a silane, preferably a polysiloxane with a modified terminal group to the polyol component as a further component A8).

The foam stabilizer brings about the formation 15 predominantly of closed cells, as a result of which the eeoc insulating effect of the foam and, with that, also the fire resistance are increased. It has been observed that the time required to burn through a closed cell foam is twice that required to burn through a predominantly open cell polyurethane foam. Furthermore, the mechanical strength of the cell structure is increased by the foam stabilizer.

18 As main component Bi), the polyisocyanate component contains at least one organic polyisocyanate with an average isocyanate functionality of more than 2.2 and preferably of 2.25 to 3.2 or more, the isocyanate functionality being the number of isocyanate groups per molecule. In this connection, it is essential to the invention that the number of isocyanate groups in the polyisocyanate, contained in the polyisocyanate component exceeds the number of reactive hydrogen atoms, namely hydroxyl groups, which are present in the constituents of the 1. 10 polyol component These extra isocyanate groups are required for producing the polyisocyanurate groups under the action of trimerization catalysts and provide the high structural strength and fire resistance desired. Accordingly, the ratio of isocyanate groups of the polyisocyanate component to the hydroxyl groups of the polyol component (that is, the NCO/OH index) is between 1.4 and 3.0 to 1 and preferably between 1.55 and 2.5 to 1. This ratio can be controlled by the type and the amount of the polyol components of the polyol component and the nature and amount of the polyisocyanate of the polyisocyanate component as well as by the ratio by weight of component to component which is employed and, for the examples described below, generally is between 1.6 and to 1.

19 The highly reactive polyisocyanates, which are used pursuant to the invention, bring about a good spatial crosslinking with all reactants used, namely with the polyols, the amines and generally hydrocarbons containing hydroxyl groups as well as the reaction with themselves. As organic polyisocyanate Bl), the polyisocyanate component preferably contains at least one polyarylpolyalkylenepolyisocyanate, for example, a polymethylenepolyphenolpolyisocyanate of the following general formula L Jn in which N is a number from 1 to 2, so that the average isocyanate functionality is at least 2, preferably at least and especially ranges from 2.25 to 3.2 or higher.

Pursuant to the invention, it is important that the ratio of isocyanate groups to hydroxyl groups in the components of the polyisocyanate component and the polyol component (A) present is between 2 and 8 to 1 and preferably between 4 and 7 to 1, the polyisocyanates preferably being used in such amounts, 20 that they supply 200 to 800% and preferably 400 to 700% of the stoichiometric amount of the isocyanate groups, which yield for the reaction of all hydroxyl groups, which are present in all polyols used as reagents.

According to the teachings of the present invention, the polyol component and the polyisocyanate component (B) must be mixed in such a manner, that there is a clear excess of isocyanate, so that an isocyanurate structure is produced by the reaction of the isocyanate due to the action of the 10 trimerization catalyst. This excess is brought about by the use of the defined ratio by weight of polyisocyanate component (B) e* to polyol component of between 1.6 and 2.5 to 1.

As additionally polyisocyanate Bl), the polyisocyanate component may contain polyisocyanates, which are normally o 15 used for the synthesis of polyurethane foams and correspond to the formula OCN-R-NCO, in which R represents an aliphatic or aromatic group, preferably an aromatic group, such as toluene diisocyanate, diphenylmethane diisocyanate, triphenyl diisocyanate, naphthyl diisocyanate, chlorophenyl-2,4diisocyanate, ethylene diisocyanate, 1,4-tetramethyl diisocyanate, p-phenylene diisocyanate, hexamethylene diisocyanate, 3,3-dimethyl-4,4-biphenylene diisocyanate, 3,3- 21 dimethoxy-4,4-biphenylene diisocyanate and, particularly, diphenylmethane-4,4-diisocyanate.

The polyisocyanate component may also contain 0.4% by weight of at least one foam stabilizer as an additional component B3). As foam stabilizer, those of the type named above can be used, and the polyol component and the polyisocyanate component may contain similar or different foam stabilizers.

Pursuant to the invention, it is furthermore possible 10 to add 0 to 3.4% by weight of an inorganic flame retardant, such as ammonium polyphosphate and preferably a powdery or particulate ammonium polyphosphate enveloped (coated) with a melamine resin to the polyol component as an additional component A9). In this connection, it is preferred that the S 15 polyol component contains the red phosphorus A5) and the inorganic flame retardant A9) in a mixing ratio of 60 to 80% by weight of red phosphorus to 40 to 20% by weight of inorganic flame retardant.

Furthermore, it is possible to add 0 to 5.0% by weight and preferably 1 to 3% by weight of an inorganic fire protection additive, such as a material forming a crust or glass, such as a 22 phosphate, a borate, a low melting silicate, an alkali metal or an alkaline earth metal oxide, hydroxide or carbonate, a watercontaining salt, an ablative material, a hydraulically setting alkaline earth aluminosilicate, plaster and/or melamine or a melamine derivative to the polyol component as an additional component As a further additional constituent or instead of the fire protective additive A10), the polyol component may contain 0 to 3.4% by weight of one or more organic flame 10 retardants, such as a halogenated hydrocarbon, a phosphoruscontaining hydrocarbon and/or a nitrogen-containing compound as additional component All), these additional constituents being used alone or in the form of mixtures. Preferred organic flame retardants are trichloropropyl phosphate, melamine, triethyl phosphate and/or salts or esters of phosphonic acid, such as diethyleneethyl phosphonate.

~In accordance with a further preferred embodiment of the invention, it is possible to add 0 to 0.9% by weight of similar or different dyes and/or pigments to the polyol component and or the polyisocyanate component as additional constituent A12). These dyes or pigments, which are preferably inorganic or organic pigments and/or organic dyes, 23 are intended to indicate to the ultimate consumer whether the two constituents, when brought out into the openings that are to be treated, are present in the suitable mixing ratio, because the presence of such dyes result in different colorations of the foaming mixture as a function of the mixing ratios of the constituents. By means of a color table and a suitable mixing device, it is therefore possible for the ultimate consumer to vary the mixing ratio as a function of the properties of the foam aimed for and to check the mixed colorations achieved.

10 In accordance with a particularly preferred embodiment .of the invention, the polyol component and the polyisocyanate component are present in separate pressure vessels, which are connected over a flexible hose with a delivery device, which includes a mixing head. Preferably, the pressure vessels are single chamber or double chamber pressure boxes of sheet steel or aluminum. Double chamber pressure boxes 0*0.* are boxes, in which the corresponding components of the .so* •o inventive polyurethane composition are contained in a flexible o pouch, which forms one chamber of the double chamber pressure box. On the other hand, in the second chamber on the outside, there is a gas under pressure, which expels the components of the polyurethane foam composition, present in the inner pouch, under pressure from the double chamber pressure box. In this 24 connection, the inner pouch of the two double chamber pressure boxes preferably is charged separately with the constituents of the polyol component or of the polyisocyanate component (B) and then filled under pressure with 20 to 50% of the given amount of the physical blowing agent A4) or B2), while the cavity between the inner pouch and the wall of the pressure box is acted upon by a gas under pressure, preferably by compressed air or nitrogen.

When such double chamber pressure boxes are used, the amount of blowing agent, introduced into the inner pouch, preferably is reduced by 50 to 80%, because the remaining expelling pressure is supplied by the gas under pressure in the outer box. Furthermore, the inner pouch, before it is filled, can be charged with mechanical devices which, on the one hand, 15 assume the function of swirling elements for swirling up the o +o• material while it is being shaken and, on the other, ensure optimum discharge of the pouch contents through the valve.

••go A further possibility of using such a double chamber pressure box consists of charging the inner pouch with the catalyst mixture and the chemical blowing agent and of introducing the main component of the material into the surrounding inner region of the double chamber pressure box and 25 supplying these components over separate hoses to the discharging device, so that, when the discharging device is actuated, a defined amount of a catalyst mixture is added to the main component automatically from the inner pouch and mixed in the static mixer of the mouthpiece of the discharging device.

Pursuant to the invention, however, separate single chamber pressure boxes are preferably filled with the constituents of the polyol component and the polyisocyanate .component respectively and then placed under pressure by the eo 10 physical blowing agent A4) or B2).

*°oS o

S

*5@4 In accordance with a further, preferred embodiment of the invention, additional swirling elements are brought into the oOe 0 pressure vessel. Preferably, these additional swirling elements have a density, which is significantly higher than that of the

S

15 surrounding medium in order thus to achieve better swirling of 5 the constituents when the pressure vessel is shaken.

S In accordance with a particular preferred embodiment of the invention, the delivery device is in the shape of a handle with a squeeze-type closing device for the supplying hoses, which are connected with the pressure vessels and fastened to the handle. The handle furthermore comprises a 26 mixing head in the form of a mouthpiece with a static mixer, by means of which the components and of the inventive polyurethane foam composition, supplied separately over the two supplying hoses, are mixed uniformly and homogeneously. In the case of this preferred embodiment of the invention, it is possible to fasten the two pressure vessels with the components of the polyurethane foam compositions, for example, to the belt of the user of the device, so that the latter, while using the equipment, need merely take hold of, with one hand, the delivery device in the form of the handle with the mixing head and, by actuating the squeeze-type closing device, release the openings of the supplying hoses, so that the two constituents of the polyurethane foam composition, under the action of the blowing agent contained in the two components, are expelled through the mixing head, in which the two components are mixed intimately, over the mouthpiece and out of the delivery device. The mixture, which emerges from the mouthpiece of the delivery device and commences to react when the components are added together, foams up, the foaming process being aided by the evaporation of the physical blowing agent present. On the basis of these chemical and physical processes, rapid foaming of the material, introduced into the regions to be treated, takes place with formation of a stable foam, which cures very rapidly. In this way, it is readily possible to line openings and/or ducts 27 in walls and/or ceilings of buildings with the heat- and flameresistant foam formed and, with that, achieve the desired fire protection.

Therefore, yet another object of the invention is a method for the fireproof sealing of openings and/or ducts in walls and/or ceilings of buildings. The method consists of ""introducing the reactive two-component polyurethane foam composition of the above-described nature with the help of the delivery device with the mixing head, in which the components 10 are mixed, into the opening and/or the duct and permitting it to foam and cure there.

The present invention accordingly provides a reactive two-component polyurethane foam composition, with which heat- .and flame-resistant foams can be generated in situ and introduced into cavities or openings, which are to be sealed against fires, by means of which the requirements of the DIN 4102 Standard can be fulfilled in preventative structural fire protection. Because of the inventive possibilities for bringing out the foam in situ with a discharging device, which is optimized for compactness and for which the polyol component (A) and the polyisocyanate component are present in separate pressure vessels, which can be fastened to the back or the belt 28 of the user and are connected over two supplying hoses with the delivery device in the form of a handle, it is possible to manipulate this application device with one hand and to apply the inventive two-component polyurethane foam composition in an extremely simple manner. Due to the compactness of the delivery device, which merely comprises the handle with the squeeze-type closing device and the mouthpiece, the maneuverability of the is not affected, so that the claimed polyurethane foam composition can be introduced even into narrow gaps in angular pipe and cable shafts. This represents a considerable advantage over conventional fire protection, bulkhead materials, which either have to be expelled manually from bulky multi-component :cartridges or pressed with the help of metering pumps into the cavities that are to be treated.

15 The inventive ratio of isocyanate groups of the polyisocyanate component to the hydroxyl groups of the polyol component (that is, the NCO/OH ratio) of between 1.4 and 3.0 to 1 is ensured by appropriately adapting the viscosity, the driving gas pressure and the cross section of the pipelines of the two components. The correct mixing ratio during the foaming can be checked by the color of the resulting foam if, in accordance with the preferred embodiment of the invention, a 29 pigment or dye is contained in one or both components and The mixing of the polyol component and the polyisocyanate component in the mixing head of the delivery device results in a stable foam, which expands once again after it is brought out into the cavities that are to be sealed. Due to the evaporation of the solvent (frothing effect), the stability of the foam, after it is brought out, is increased even more. Due to physical effects, namely the evaporation of 10 the physical blowing agent, or chemical effect, for example, the reaction of the water with the polyisocyanate with formation of carbon dioxide, the exothermic chemical reaction, which sets in about 20 to 60 seconds later, leads to a further formation of gas. The stable foam, brought out in this manner, can be o e 15 introduced even into the cavities to be treated, for example, between cable, cable routes and openings, into fissures and gaps of the masonry, shutting these off tightly and firmly. The foam is tack-free after 30 to 180 seconds and can be cut if required.

The inventive, reactive two-component polyurethane foam composition is distinguished by a series of advantages in comparison to conventional polyurethane foams.

30 For example, the foam cures independently of the surroundings, that is, it is significantly less susceptible to a low relative humidity or to low temperatures, since all reactants are contained completely in the components and For example, even at underground temperatures of 5 0 C, the desired reaction, with foaming and curing, can be brought about without any difficulties.

.o The fire behavior of this foam differs significantly from that of conventional polyurethane foams. The carbonization rate is a third to a quarter of that of conventional polyurethane foams, that is, the foam withstands a flame at a temperature of about 900 0 C for a period three to four times as ee long.

Because solid, intumescing materials, which increase their volume considerably when heated in the case of a fire, are not used, the carbon crust formed is significantly sturdier than that formed by known polyurethane foams and can thus be removed less rapidly by the mechanical action of the turbulent combustion gases. As a result, in the event of a fire, the foam has a significantly higher strength with a high thermal insulation capability, as a result of which improved fire protection is imparted to the material below. When solid 31 intumescing materials are used, a brittle, rigid matrix results, which chips off and cracks, so that a thermally insulating carbonized foam layer, which brings about the insulating capability desired for protecting the material below, is not formed.

**Before the combustion, the foam structure produced is very solid with a compression strength of iN/mm 2 in comparison 9 .00 to conventional structural foams with a compression strength of see only 0.03N/mm 2 This very solid foam structure is very helpful 10 in the event of a fire. If, for example, a cable duct is sealed with the inventive two-component polyurethane foam composition, the solid foam secures the cable sheathing, which swells up in the event of a fire because of the high thermal conductivity of 0.0.the copper leads, so that the cables mutually seal one another 15 when the inventive material is used. Hot and poisonous combustion gases can then not flow between the cables through the cable shaft.

In the event of a fire, the foam, produced pursuant to the invention, depolymerizes very slowly. The shrinkage effect during the depolymerization is surprisingly slight and largely prevents the resulting openings for the passage of fumes.

32 The foam, produced using the inventive two-component polyurethane foam composition, has an expansion pressure, which is greater by a factor of about 10 than that of conventional single component polyurethane foams, as used for construction purposes. This high foam pressure forces the foam into all crevices of the opening to be treated and presses it intimately against the building component soffit, as a result of which a e :...positive, tight fire insulation is achieved.

The inventive polyurethane foam composition exhibits 10 outstanding adhesion to all typical construction substrates.

000* J9 S Even under extreme climatic conditions, the fire protection foam, produced using the inventive polyurethane foam composition, does not exhibit measurable shrinkage in a 20 mm gap in wood. Conventional foams used in construction contract up to 4 mm in a 20 mm gap in wood. In rigid gaps, this leads to crack formation in the foam or at the component soffit. In fire tests, such cracks caused the component to fail within minutes, in that it burns through.

In contrast to conventional polyurethane foams, the foam, produced from the inventive, two-component polyurethane foam composition, exhibits no dripping or flowing of the foam, 33 when the latter is heated to a temperature ranging from 250 0 C to 450 0 C, so that the opening, closed off with this foam, remains closed off. Even in the event of smoldering fires, the inventive polyurethane foam composition provides outstanding fire protection.

The following example explains the invention further.

The composition of the polyol component and the polyisocyanate component is given in the following Tables 1 and 2.

*0 oo *o *o 34 Table 1: Polyol Component (A) 0. 0.

Numer Component Percentage Al) Aromatic polyester alcohol in diethylene glycol- 48.9 (approx._90%) OH number 178 (Terol 196) A7) Polyether polyol with an OH number of 400 3.8 ~(Lupranol 3321) A6) 1,4-Dikiydroxybutale 1.4 (OH number 1240, density 1.02) A6) Glycerol OH number 1800, density 1.23) 0.3 Trichloropropyl phosphosphate All)- Triethyl phosphate 5.4 A2) Trimerizing catalyst (potassium salt 0.7 (catalyst LB) A2) Dimethylcyclohexylamile 0.2 (catalyst for the urethane reaction) A3) Tertiary amine catalyst (Polycat 43) 0.3 A3) Water 0.9 AB) Red dye dispersed in a poyeter polyol 0.7 (Renol LC-FU) AS) Foam stabilizer polydimethylsiloxale polyether 0.7 copolymer (Tegostat 8471) A9) Ammonium polyphosphate 3.2 (coated with a melamine resin) Red phosphorus (coated with a melamine 7.6 formaldehyde resin) A4) 1,1,1,2-Tetrafluoroethane (blowing agent 134a) 1.

A4) Methyl ether 0.4 100 Table 2: Polyisocyanate Component (B) Number Component Percentage B1) Diphtenylmethane-4,4-diisocyanate and homoEog-ues 88.2 and isomers, density 1,25, viscosity approx.

600 mPas at 75 0 C (Suprasec 2085) B3) Foam stabilizer (polydimethylsiloxane-polyether 0.3 copolymer) (Tegostab 8471) B4) Blue dye powder form (Renal Blue A2R-E) 0.9 B2) 1,1,1,2-Tetrafluoroethale (blowing agent 134a)T -5.9 B3) Propane/butane mixture (0.25/99.75) 4.7 35 The constituents, given above, are mixed and brought into separate boxes A and B, the blowing gas mixture of blowing agent 134a and methyl ether or the propane/butane mixture in each case being forced in under pressure at the end.

With the help of two supplying hoses, the pressure vessels are connected with a delivery device in the form of a handle with a mouthpiece, the mouthpiece containing a mixing head with a static mixer. When the squeezing valve, present in the handle, is actuated, the two hoses are opened, so that the respective components A and B, under the action of the internal pressure of the blowing agent, are forced through the hoses into the mixing head of the delivery device and into the mixer present therein and emerge from the mouthpiece with foaming.

Because of the large expansion force of the polyurethane foam composition, even larger openings and ducts through walls and/or ceilings can be sealed in this way, a high strength of the fire protection foam being attained after the material cures even under unfavorable weather conditions, that is, at low temperatures and a low relative humidity.

Comparison Example To illustrate the improved fire protection properties of the with the help of the reactive two-component polyurethane 36 foam composition, foams were produced in accordance with DE-A-42 34 374 and GB-B-14 04 822 and introduced into openings with a diameter of 110 mm in 100 mm thick foam mortar. After exposure to a flame for 30 minutes at 900 0 C, the properties, given in the following Table 3, were obtained.

Table 3: Properties after DE 42 34 374 GB 14 04 822 Inventive foam exposure to a flame Residual height 93 mm 95 mm 98 mm (original height 100 mm Thickness of 30 mm 30 mm 40 mm unchanged foam Thickness of the 25 mm 20 mm 20 mm yellowish decomposition layer Ash evaluation Heavy, yet not Light, Light, yet very solid, highly solid, torn compact, no large grooved apart cracks Edge evaluation 10 mm wide 10 mm wide 5 mm wide gap width (maximum) 25 mm deep 25 mm deep 10 mm deep Density (kg/m 78 70 It is evident from the Table above that the foam, produced from the inventive reactive two-component polyurethane foam composition, exhibits a distinctly better fire behavior than do the products of the state of the art. The properties given show that a significantly better fire resistance can be obtained with the inventive polyurethane foam composition.

Claims

1. A reactive two-component polyurethane foam composition for producing heat- and flame-resistant foams, with a polyol component and a polyisocyanate component characterized in that the polyol component contains Al) 39.5 to 92.2% by weight of at least one polyester alcohol with a hydroxyl number ranging from 130 to 550 and a viscosity of 4,000 to 10,000 mPas A2) 0.6 to 4.0% by weight of one or more catalysts for the reaction between the polyol and the polyisocyanate, A3) 0.2 to 1.4% by weight of at least one chemical blowing *agent, S" A4) 6.5 to 32.5% by weight of at least one physical blowing agent and 15 A5) 0.5 to 22.5% by weight of the red phosphorus; the polyisocyanate component contains Bl) 78.9 to 99.9% by weight of at least one organic polyisocyanate with an average isocyanate functionality of more than 2.2 and B2) 0.1 to 21.1% by weight of at least one physical blowing agent; the ratio of isocyanate groups of the polyisocyanate component to the hydroxyl groups of the polyol component is between 1.4 and 3.0 to 1; and the foam composition is free of 38 solid intumescing materials, which increase their volume when heated.

2. The two-component polyurethane foam composition of claim 1, characterized in that, as polyester alcohol Al), the polyol component contains an aromatic polyester alcohol.

3. The two-component polyurethane foam composition of at least one of the claims 1 or 2, characterized in that, as catalyst A2), the polyol component contains a mixture of catalysts, which catalyze the reaction of the polyol with the 10 polyisocyanate with formation of polyisocyanurate groups (trimerization catalyst) and optionally of polyurethane groups and/or polyurea groups.

4. The two-component polyurethane foam composition of claim 3, characterized in that, as catalyst A2), the polyol component contains a mixture of tin salts of organic acids, alkali salts and/or alkaline earth salts of organic and/or inorganic acids, lead salts of organic acids and/or aliphatic and/or aromatic amines. and/or aromatic amines. 39 The two-component polyurethane foam composition of claim 3, characterized in that, as trimerization catalyst, the polyol component in the catalyst mixture A2) contains a strong base, an alkali metal carboxylate and/or a tertiary amine.

6. The two-component polyurethane foam composition of claims 3 to 5, characterized in that, as catalyst mixture A2), the polyol component contains a mixture of dimethylcyclohexylamine and/or a disubstituted amine, such as tetramethyliminobispropylamine.

7. The two-component polyurethane foam composition of at least one of the claims 1 to 6, characterized in that, as i chemical blowing agent A3), the polyol component contains water. S

8. The two-component polyurethane foam composition of at least one of the claims 1 to 7, characterized in that, as physical blowing agents A4) and B2), the polyol component (A) and the polyisocyanate component contain similar or different blowing agents or blowing agent mixtures. 40

9. The two-component polyurethane foam composition of claim 8, characterized in that the physical blowing agent A4) or B2) is a blowing agent with a boiling point at a standard temperature and pressure of not more than 170 0 C and preferably of not more than 75 0 C and particularly of not more than 0°C. The two-component polyurethane foam composition of at least one of the claims 8 to 9, characterized in that the physical blowing agents A4) and B2) comprise at least one fluorine-containing blowing agent. 10 11. The two-component polyurethane foam composition of o• claim 10, characterized in that, as fluorine-containing blowing agent A4) and B2), 1,1,1,2-tetrafluoroethane (blowing agent 134a) and/or 1,1,1,2,3,3,3-heptafluoropropane (blowing agent 227) is contained.

12. The two-component polyurethane foam composition of one of the claims 8 to 11, characterized in that, as physical blowing agent A4) and B2), a mixture is contained, which is selected from fluorine-containing blowing agents, propane, butane and/or methyl ether. 41

13. The two-component polyurethane foam composition of at least one of the claims 1 to 12, characterized in that, as component A5), the polyol component contains coated or microencapsulated red phosphorus.

14. The two-component polyurethane foam composition of at least one of the claims 1 to 13, characterized in that, as additional component A6), the polyol component contains 0 to 1.9% by weight of a further hydrocarbon, which reacts with the polyol component and has a hydroxyl number ranging from 900 to 2,000 and a viscosity of 1,000 to 5,000 mPas.

15. The two-component polyurethane foam composition of claim 14, characterized in that, as further hydrocarbon A6), which reacts with the polyol component, the polyol component A6) contains an aliphatic diol.

16. The two-component polyurethane foam composition of claim 15, characterized in that, as aliphatic diol A6), the polyol component contains 1,4-dihydroxybutane and/or glycerol. &V 42

17. The two-component polyurethane foam composition of at least one of the claims 1 to 16, characterized in that, as additional component A7), the polyol component contains 0 to by weight of a polyether alcohol with a hydroxyl number ranging from 600 to 1,200 and a viscosity of 4,000 to 10,000 mPas.

18. The two-component polyurethane foam composition of claim 17, characterized in that, as polyether alcohol A7), the polyol component contains an aromatic polyether alcohol. 10 19. The two-component polyurethane foam composition of at least one of the claims 1 to 18, characterized in that, as additional component A8), the polyol component contains 0.1 to 1.0% by weight of at least one foam stabilizer. 6

20. The two-component polyurethane foam composition of at least one of the claims 1 to 19, characterized in that, as organic polyisocyanate Bl), the polyisocyanate component (B) contains at least one polyarylpolyalkylenepolyisocyanate with an average isocyanate functionality of 2.25 to 3.2 or more, preferably polymethylene-polyphenyl-polyisocyanate and/or diphenylmethane-4,4'-diisocyanate. 43

21. The two-component polyurethane foam composition of at least one of the claims 1 to 20, characterized in that, as additional component B3), the polyisocyanate component (B) contains 0 to 0.4% by weight of at least one foam stabilizer.

22. The two-component polyurethane foam composition of claim 21, characterized in that the polyol component and the polyisocyanate component contain similar or different organic foam stabilizers.

23. The two-component polyurethane foam composition of 10 claim 22, characterized in that as organic silicone foam o stabilizer, the polyol component and the polyisocyanate component contain a surface-active siloxane and/or a silane, preferably a polysiloxane with a modified terminal group.

24. The two-component polyurethane foam composition of at least one of the claims 1 to 23, characterized in that the S polyol component contains the red phosphorus A5) in a form, in which it is coated by a melamine resin. 44 The two-component polyurethane foam composition of at least one of the claims 1 to 24, characterized in that, as additional component A9), the polyol component contains 0 to 3.4% by weight of an inorganic flame retardant.

26. The two-component polyurethane foam composition of claim 25, characterized in that, as inorganic flame retardant A9), the polyol component contains ammonium polyphosphate preferably coated by a melamine resin. e e a.*

27. The two-component polyurethane foam composition of claims 25 and 26, characterized in that the polyol component (A) contains a mixture of the red phosphorus A5) and the inorganic flame retardant A9) in a ratio of 60 to 80% by weight of red phosphorus to 40 to 20% by weight of inorganic flame retardant.

28. The two-component polyurethane foam composition of 15 at least one of the claims 1 to 27, characterized in that, as additional component A10), the polyol component contains 0 to 5.0% of an inorganic flame retardant additive. 45

29. The two-component polyurethane foam composition of claim 28, characterized in that, as inorganic flame retardant additive A10), the polyol component contains a crust-forming or glass-forming material, such as a phosphate, a borate, a low- melting silicate, an alkali metal or alkaline earth metal oxide, hydroxide or carbonate, a water-containing salt, an ablative material, a hydraulically binding alkaline earth aluminosilicate, plaster and/or melamine or a melamine derivative. 10 30. The two-component polyurethane foam composition of at least one of the claims 1 to 29, characterized in that, as S" additional component All), the polyol component contains 0 to 3.4% by weight of one or several organic flame retardants.

31. The two-component polyurethane foam composition of S 15 claim 30, characterized in that the polyol component (A) oooo contains an organic flame retardant selected from halogenated hydrocarbons, phosphorus-containing hydrocarbons and/or nitrogen-containing compounds individually or in the form of a mixture. 46

32. The two-component polyurethane foam composition of one of the claims 30 to 31, characterized in that, as organic flame retardant All), the polyol component contains trichloropropyl phosphate, melamine, triethyl phosphate and/or salts or esters of phosphonic acid, such as diethyleneethyl phosphonate.

33. The two-component polyurethane foam composition of one of the claims 1 to 32, characterized in that, as additional component A12) and B4), the polyol component and/or the 10 polyisocyanate component contains 0 to 0.9% by weight of **oo similar or different dyes or pigments.

34. The two-component polyurethane foam composition of claim 33, characterized in that, as pigment or dye, an inorganic or organic pigment and/or an organic dye is contained. 15 35. The two-component polyurethane foam composition of at least one of the claims 1 to 34, characterized in that the polyol component and the polyisocyanate component are in separate pressure vessels, which are connected in each case over a flexible hose with a delivery device with a mixing head. 47

36. The two-component polyurethane foam composition of claim 35, characterized in that the pressure vessels are single chamber or double chamber pressure boxes of sheet steel or aluminum.

37. The two-component polyurethane foam composition of claim 36, characterized in that the single chamber pressure boxes are charged with the constituents of the polyol component or of the polyisocyanate component and then filled under pressure with the physical blowing agents A4) and/or B2). 10 38. The two-component polyurethane foam composition of claim 37, characterized in that the inner pouch of the double chamber pressure boxes is charged with the constituents of the polyol component or the polyisocyanate component and then filled under pressure with 20% to 50% of the given amount of the physical blowing agent A4) and/or B2) and the cavity between the inner pouch and the wall of the box is acted upon by a gas under pressure. 48

39. The two-component polyurethane foam composition of one of the claims 34 to 37, characterized in that the pressure vessels additionally contain swirling elements, which preferably have a density, which is significantly higher than that of the surrounding medium, for swirling the constituents. The two-component polyurethane foam composition of at least one of the claims 35 to 39, characterized in that the delivery device has the shape of a handle with a squeeze-type closing device for the supplying hoses fastened to the handle S1:' 0 and a mixing head in the form of a mouthpiece with a static mixer.

41. The method for the fire-protective sealing of openings and/or ducts in wall and/or ceilings of buildings, characterized in that the reactive two-component polyurethane 15 foam composition of at least one of the preceding claims is introduced into and foamed and allowed to cure in the opening and/or the duct with the help of the delivery device with a mixing head, in which the two components are mixed.

42. A reactive two-component polyurethane foam composition for producing heat and flame-resistant foams substantially as herein described with reference to any one 49 of the embodiments of the invention illustrated in the accompanying examples. DATED this 10th Day of November, 1999 HILTI AKTIENGESELLSCHAFT Attorney: CAROLINE M BOMMER Fellow Institute of Patent Attorneys of Australia of BALDWIN SHELSTON WATERS