Compositions – Fire retarding – Intumescent
Reexamination Certificate
1999-08-06
2003-04-08
Medley, Margaret (Department: 1714)
Compositions
Fire retarding
Intumescent
C427S154000, C427S445000, C428S703000, C428S913000, C428S920000, C428S921000, C442S414000, C442S417000, C523S179000, C523S142000, C523S217000, C523S310000, C524S196000, C524S415000, C524S416000, C524S499000, C524S589000, C524S590000
Reexamination Certificate
active
06544445
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a fire-resistant elastic closure for openings in the form of a preformed composite block.
In structural components (walls, ceilings) classified under fire prevention regulations, openings are not permitted because, in the event of a fire, flames and smoke can spread through the openings into the adjoining rooms. Above all in cases where lines (cables, pipes) are passed through these openings, the material which is to be used to close the rest of the opening has to satisfy particular requirements. Hitherto, the following means have been used to seal openings of the type in question:
mineral fiber boards or loose mineral fibers in combination with fireproof coatings and putties,
mortar products,
fireproof pads and
polyurethane foam elements.
Some of these products have very good properties. However, the ideal solution lies in a combination of simple production and processing coupled with low material costs, high fire resistance and the possibility of rapid installation and removal.
A fireproof and smoke-proof closure for wall openings is known from German Utility Model G 87 16 908.6. This closure is made in the form of a conical stopper by foaming a fine-cell two-component foam in a suitable mold. In practice, it has been found that these conical stoppers are attended by handling difficulties which are aggravated by their tacky outer skin. In addition, numerous hollow molds have to be kept on hand in order to obtain stoppers differing in size.
A fire-retardant composite foam of polyurethane foam flakes is described in DE 35 42 326 C1. It is made by mixing the foam flakes with intumescent compounds which expand in the event of fire as a binder and/or additive and then press-molding the resulting mixture. Intumescent compounds in the form of expanded graphite may be used as the additive while intumescent compounds in the form of an epoxy resin with a melamine hydrohalide as binder may be used as the binder. The composite foam thus obtained is suitable as a composite foam panel which is placed over surfaces to be protected.
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a fire-resistant elastic closure for openings in the form of a preformed composite block of
a) at least one type of elastically compressible particles,
b) at least one heat-activated expanding agent,
c) at least one heat-activated binder and
d) at least one adhesive by which the elastically compressible particles and the other constituents are joined to form the composite block.
The closure according to the invention is easy to make and may consist largely or entirely of recycled material. The closure according to the invention has excellent mechanical properties, particularly in regard to strength, abrasion resistance and elasticity. The closure according to the invention also has excellent fire-resistant properties. It may readily be formulated in such a way that it has a fire resistance of >F90 according to DIN 4102. Its fire resistance is thus of the same order as that of concrete components which is particularly advantageous.
In the event of fire, the heat-activated expanding agent leads to an increase in volume and provides for particularly tight sealing of the opening. Also, additional voids are created which increase heat insulation. The at least one heat-activated binder becomes tacky under the effect of heat and ensures that the individual constituents of the composite block hold together and do not disintegrate into crumbs in the event of fire. In one advantageous embodiment, at least two heat-activated binders kicking in at different temperatures are provided. Suitable heat-activated binders are, in particular, organic thermoplastics which melt at low temperatures, inorganic hotmelt adhesives, such as borates, ammonium polyphosphate, which softens over a broad temperature range and at the same time has flame-retardant properties, and glass which develops its adhesive properties at relatively high temperatures. The glass is preferably present in fine-particle form, more particularly in the form of fibers, hollow microbeads or glass powder, in particular to avoid separation of the raw materials.
In one preferred embodiment, at least two expanding agents expanding at different temperatures are provided as expanding agents. This also enables the expansion properties to be controlled over a broad temperature range. Particularly suitable expanding agents are expanded graphite and—where expansion is also desirable at high temperatures—unexpanded vermiculite and/or perlite.
To produce the composite block, the individual constituents may be premixed in fine-particle form and then mixed with the adhesive which is preferably sprayed onto the stirred mixture. The mixture wetted with the adhesive is then press-molded into a block, preferably under the effect of heat which may be uniformly introduced into the mixture, more particularly by a pulse of steam.
In one preferred embodiment of the invention, the at least one expanding agent and the at least one heat-activated binder are present in the form of granules containing both constituents. Highly uniform distribution of the constituents in the closure is obtained in this way, resulting in highly uniform mechanical and fire-retardant properties. Particularly suitable granules of this type are described as a swelling agent composition in DE 39 30 722 A1. Reference is expressly made here to the disclosure of that document. In general, the composite blocks are made up of 10 to 50% by weight and more particularly around 40% by weight of elastically compressible particles, 20 to 70% by weight and, more particularly, 40 to 60% by weight of the combination of heat-activated expanding agents and heat-activated binder and 0.5 to 20% by weight and more particularly around 10% by weight of adhesive. The combination of heat-activated expanding agent and heat-activated binder generally splits up into 40 to 80% by weight and more particularly 30 to 50% of expanding agent, more particularly expanding agent mixture, and 60 to 20% by weight and more particularly 70 to 50% by weight of binder, more particularly binder mixture.
In one preferred embodiment, the adhesive which holds the constituents of the composite block together is a diisocyanate, more particularly diphenyl methane diisocyanate, which is preferably set with water. The water of the steam pulse or the aqueous medium with which the adhesive is added may be used for setting. In another preferred embodiment of the invention, the adhesive which holds the constituents of the composite block together is a thermoplastic, more particularly a thermoplastic which can be applied in an aqueous medium, for example in the form of a dispersion. This thermoplastic may simultaneously act as the heat-activated binder. Examples of such thermoplastics are polyvinyl acetate/ethylene copolymers and polyvinyl acetate/ethylene/vinyl chloride terpolymers.
The closure according to the invention is preferably porous and, more particularly, has a rough surface. On the one hand, this makes it particularly compressible. On the other hand, the rough surface provides for effective adhesion in the openings to be closed.
Interestingly, it has been found that, despite its heterogeneous composition, the closure according to the invention has the properties of a homogeneous material. This is partly attributable to the fact that the particle sizes of its individual constituents, more particularly the elastically compressible particles, are different which provides for a uniform and dense packing. The elastically compressible particles may be substantially solid, such as pieces of rubber or pieces of cork. However, they are preferably porous. Thus, in one preferred embodiment, the composite block is a composite foam block while the elastically compressible particles are foam particles. Other suitable compressible particles are balls of fibers. Fibers and other compressible particles may also be present in combination with one another. In preferred embodiments, the elastically com
Graf Robert
Kaiser Maria-Elisabeth
Drach John E.
Henkel Kommanditgesellschaft auf Aktien
Trzaska Steven J.
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