JPH05317452A - Powdery digestive - Google Patents

Abstract

PURPOSE: To realize a dry-powder fire extinguishing agent with high fire extinguishing activity, by constituting the extinguishing agent of an ordinary base material for dry-powder fire extinguishing agent and a mixture of thermoplastic elastic rubber of a specific block polymer coated or surrounded by a little amount of hydrophobic silica. CONSTITUTION: This powder fire extinguishing agent is constituted of an ordinary component for dry-powder fire extinguishing agent and a mixture of a specific thermoplastic elastic rubber-block copolymer and a little amount of hydrophobic silica. The block copolymer is selected from a group consisting of monovinyl-allene-conjugate diene-block copolymer, monovinyl-allene- monoolefin block copolymer, and a hydrogenated derivative of such the block copolymer. The hydrophilic silica is used by 0.1-3.0wt.% based on the amount of the thermoplastic elastomer block copolymer and combined with the block copolymer by a simple method so as to provide a sufficiently uniform surface coating.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a powder digestive agent according to the preamble of claim 1. Currently, there are essentially three types of powder extinguishing agents: • Gas fires and flame fires (Flammenbrand).
BC powder extinguisher to.・ ABC powder extinguishing agent for ember fire, gas fire and flame fire. D powder extinguisher or AB as a special powder extinguishing agent, eg for metal fires or as a universal powder extinguishing agent for ember fires, liquid fires, gas fires and metal fires
CD powder extinguisher.

Powdered extinguishing agents are thoroughly mixed in a gas stream, often compressed air or a gas stream consisting of gaseous carbonic acid or nitrogen, and injected into the fire until the fire is extinguished. The powder extinguisher base (Basisstoff) is usually the following chemicals: BC powder extinguisher: sodium bicarbonate,
Potassium sulfate, potassium hydrogen carbonate; ABC powder extinguishing agent:
Ammonium phosphate + ammonium sulphate and barium sulphate and components of BC powder extinguisher; D or ABCD powder extinguisher: sodium chloride, potassium chloride, melamine or boron trioxide and components of ABC powder extinguishing agent.

The powder extinguishing agent also contains, for example, additives for improving resistance to deterioration, lubricity and fluidity, stickiness or adhesion to an object to be burned, and additives for preventing agglomeration. Formulations for improving resistance to alteration are eg hydrophobizing agents such as waxes, metal stearates, especially silicones. The digestive effects of powder-type extinguishing agents are various, with BC powder acting mechanically by the powder flow by heterogeneous inhibition, while ABC powder is formed by the formation of a transparent layer (Glasurschicht) that blocks oxygen supply. Digests by controlling gas generation and promoting carbonization of solid materials. Metal fire-powder extinguisher (D-powder extinguisher) melts and sinters to form a low porosity, hard crust that blocks oxygen supply.

In general, the powder extinguishing agent and its decomposition products should be physiologically harmless when they hit the fire source, should be digested very well so that they can be moved long lastingly and satisfactorily. Conductive bridges should not form upon impact with the device. In particular, ABC powders often contain a proportion of diluent (inert powder) for cost reasons, which significantly reduces digestion.

An object of the present invention is to provide a powder digestive agent having a high digestive action. This object is solved by the features of claim 1. Advantageous other developments of the invention are revealed in the embodiments described at the end of the specification. According to it, the present invention provides the usual constituents of a powder extinguisher and a monovinyl-arene-conjugated diene-block copolymer, monovinyl-arene-monoolefin, coated or surrounded by a small amount of hydrophobic silica (silica, silicon dioxide). Selected from the group consisting of block polymers and hydrogenated derivatives of such block copolymers,
It is based on a composite action with a thermoplastic elastic rubber known per se. In this case, this effect is achieved in all types of powder extinguishing agents, but is particularly pronounced in BC powder extinguishing agents. The powder extinguisher according to the present invention comprises the usual ingredients of a powder extinguisher as well as certain thermoplastic elastic rubber
It is a mixture of a block copolymer and a mixture of small amounts of hydrophobic silica, with highly dispersible silicified pyrogen silicic acid or hydrophobic diatomaceous earth being preferred as the hydrophobic silica.

The copolymer may be a vinyl aromatic monomer / conjugated diene-block copolymer comprising a monovinyl aromatic polymer block combined with a conjugated diene-polymer block, or at least one monovinyl aromatic polymer block combined with a monoolefin polymer block. Including vinyl aromatic monomer / monoolefin monomer block copolymers as well as hydrogenated derivatives of these block copolymers. Block copolymers are especially
A linear binary block of a thermoplastic elastomer, including a conjugated vinyl diene or elastomeric monoolefin polymer block and a monovinylaromatic polymer block bound, including hydrogenated derivatives of such polymer block--a ternary block--. Radial and graft block polymers. The general structures of block molecules are linear ABAA block type, radial or graft AB block type and double AB block type. In this case, "A" means monovinyl aromatic polymer or hydrated polymer block and "B" means elastomer conjugated diene, hydrogenated diene, monoolefin or hydrogenated monoolefin polymer block. Monovinyl aromatic polymer blocks include either homopolymer blocks or copolymer blocks and are primarily important as monovinylaromatic monomers as the primary polymerized units. The conjugated diene- and hydrogenated diene polymer blocks and the mono-olefin and hydrogenated mono-olefin polymer blocks may be either homopolymeric or copolymeric species, their important property being that they have a composition that exhibits elastomeric properties. ..

Both blocks "A" and "B" can be partially or fully hydrogenated. If only partially hydrogenated, it is preferred that block "B", the conjugated diene polymer block, be hydrogenated so that it is less susceptible to oxidation. Therefore, these polymers can include unhydrogenated or partially or fully hydrogenated block polymers.

Monovinyl aromatic monomers that can be used to form the block copolymers according to the present invention include styrene, α-
Includes methyl styrene and cyclic alkylated styrene. These are either the mutual or a small amount of the conjugated diene and the block "A".
To form a copolymer. Conjugated dienes that can be used for the formation of block "B" or as a minor component in block "A" are especially conjugated dienes having 4 to 8 carbon atoms, especially butadiene and isoprene. Monoolefins that can be used to form the block "B" preferably have 2 to 8 carbon atoms, and ethylene, propylene and butylene are particularly preferable. Preferred mono-olefin "B" blocks include ethylene / propylene and ethylene / butylene copolymers. Representative block copolymers have the following constructions: polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene and polystyrene-poly (ethylene / butylene) polystyrene ABA ternary block copolymers; polystyrene-polybutadiene and polystyrene-poly. A-B radial or graft block copolymers of isoprene; polystyrene-polybutadiene, polystyrene-poly (ethylene / propylene) and polystyrene-poly (ethylene / butylene) AB binary block copolymers.

Preferred block copolymers are polystyrene-polybutadiene-polystyrene and polystyrene-
Linear AB of poly (ethylene / butylene) polystyrene
-A ternary block copolymer. In particular, the present invention refers to thermoplastic elastic rubbers under the trade names Kraton D and K.
raton G Shell Chemical Company (Sh
Materials such as those provided by the El Chemical Company (Houston, TX) are suitable. The most preferred materials are available from the manufacturer in pellet or powder form. The powder form is currently preferred.

Hydrophobic silica additives for use in compositions according to the invention with thermoplastic elastomers have been published in the technical and patent literature and are commercially available. The hydrophobic silica compound can be treated to render it hydrophobic. Essentially any type of silicon-containing compound can be included, including silica, diatomite, diatomaceous earth and other forms of diatomaceous earth. According to the invention, trade names Aerosil R-972, R-972
V, R-974, R-974V, R-976 at Degussa Corporation
(Lichfield, NJ)
Hydrophobic amorphous fuming silica compounds available from Park) are particularly preferred. Silica Compounds R-972 and R-97 Treated Totally with Dimethyldichlorosilane
4 is preferable. The hydrophobic silica is used in an amount of 0.1 to 3.0% by weight, especially 0.3 to 0.7% by weight, based on the amount of thermoplastic elastomer block copolymer.

The hydrophobic silica is easy to combine with the block copolymer by a simple mixing method, so that the polymer has a sufficiently uniform surface coating.

When using the powder extinguishing agent according to the invention, it has been found that a kind of viscous carpet or related layers is formed, but this formation has not yet been elucidated. This layer, when dropped at the fire source or fire site, significantly reduces the generation of flammable gases after extinguishing, especially in the case of liquid fires, significantly preventing flashback and actually avoiding explosive flashback. Become. This layer is quite heavy and stays on fire. This layer adheres to the fire spot and is surprisingly totally lifted up again after the fire spot has cooled. To that extent, the adhesiveness of this layer at the source of the fire at elevated temperatures can be exploited and the layer will be transported to the fire site as a new normal powder extinguisher and / or an inert powder, based on the adhesive action of the layer. Localize. Since the new powder extinguisher is foam compatible, it is possible to use the foam extinguisher and the powder extinguisher according to the present invention together.

After cooling the fire spot, the layer can be easily removed or treated in whole or in part, so that the waste treatment of the cooled fire spot is simple. The powder extinguishant guarantees this most desirable property, as this layer very effectively prevents flashback reproduction. Layering contributed by the usual constituents of powdered extinguishing agents (rather than the usual constituents do not produce noticeable or useful layering)
Apart from the usual ingredients, even if present in small amounts,
As is known, it is as effective as the usual powdered extinguisher without the mixture according to the invention. Moreover, the synergistic action of the mixing partners results in a high degree of digestibility, adsorption or absorption or coagulation (Abbindung) of flammable liquids based on the amount of powdered extinguishing agent comparable to the usual ingredients.

The new powder extinguisher is harmless, long lasting,
It is flexible, does not aggregate and can move particularly well. No special additives known per se for improving the durability or lubricity or flowability are necessary. Moreover, the hydrophobizing agents that conventional powder-digesting agents inevitably require are unnecessary, which simplifies the production of new powder-digesting agents. However, additives known per se may be present as long as the user desires.

The novel powder extinguishing agent is preferably 100-.
It is preferred to include up to 30% by weight of copolymers used in particle sizes of 300 μm, in particular 180-220 μm. The particular digestibility of the novel powdered digestive agents is likely due to the non-agglomerating interactions after mixing the particles of the powdered digestive agent's normal ingredients with the particles of the copolymer. The particles do not readily decompose again after mixing. The interaction of the particles with each other results in a very advantageous layering, which results in a completely new digestibility with a small amount of powdered extinguishing agent.

Another particular advantage of the present invention is that the powder extinguishing agent according to the invention is also capable of being used as a multipurpose powder by virtue of its ability to adsorb or absorb liquid in the event of a liquid fire. .. In this case, the formation of a closed layer on the digested liquid fire results in that the powder used for the digestion can be easily removed together with the liquid it has absorbed and can be disposed of without problems. The powder extinguishing agent according to the invention can also serve as a pure adsorbent or absorbent, especially for flammable liquids, which can help prevent fires.

The novel powdered extinguishing agent is not compressed either in packaging or in the digestive system. Filling the digestive tract with the powdered digestive agent according to the invention is also very simple due to its good flowability. The powder extinguishing agent according to the invention is very effectively released from the digestive organs as a cloud of powder in a uniform jet state during its use.

Claims (12)

[Claims] 1. A monovinyl-coated, conventional base for powder extinguishing agents and coated or surrounded by a small amount of hydrophobic silica.
Composed of a mixture with at least one thermoplastic elastic rubber selected from the group consisting of allene-conjugated diene-block copolymers, monovinyl-arene-monoolefin-block polymers and hydrogenated derivatives of such block copolymers. Powder extinguisher. 2. The powdery extinguishing agent according to claim 1, wherein the amount of the hydrophobic silica is 0.1 to 3.0% by weight based on the amount of the thermoplastic block copolymer. 3. The powder extinguishing agent according to claim 1, wherein the amount of hydrophobic silica is 0.1 to 0.7% by weight based on the amount of the thermoplastic elastic block copolymer. 4. A block copolymer having at least one monovinylaromatic polymer block bonded to an elastomeric conjugated diene polymer block; at least one monovinylaromatic polymer block bonded to an elastomeric monoolefin polymer block and such. 4. A thermoplastic elastomer linear binary block polymer, ternary block polymer and radial or graft polymer selected from the group consisting of hydrogenated derivatives of block copolymers. Powder extinguisher. 5. The powder extinguishing agent according to claim 4, wherein the elastomer block polymer is at least partially hydrogenated. 6. The powder extinguisher according to claim 4, wherein the non-elastomeric monovinyl aromatic polymer block is at least partially hydrogenated. 7. The block copolymers have the following constructions: polystyrene-polybutadiene-polystyrene, polystyrene-polyisoprene-polystyrene and polystyrene-poly (ethylene / butylene) polystyrene A-B-A ternary block copolymers; polystyrene-polybutadiene and polystyrene. An AB radial or graft block copolymer of polyisoprene; selected from block copolymers having polystyrene-polybutadiene, polystyrene-poly (ethylene / propylene) and polystyrene-poly (ethylene / butylene) AB binary block copolymers The powder digestive agent according to any one of claims 1 to 6, which is characterized in that. 8. A powder extinguishing agent according to any one of claims 1 to 7, which is a BC powder extinguishing agent and contains sodium hydrogen carbonate and / or potassium sulfate and / or potassium hydrogen carbonate as a base. .. 9. An ABC powder extinguishing agent, comprising ammonium phosphate + ammonium sulfate and / or barium sulfate and a BC powder extinguishing agent component as a base. Powder extinguisher. 10. A D powder extinguisher or an ABCD powder extinguisher, which has sodium chloride and / or potassium chloride and / or melamine or boron trioxide and ABC as a base.
8. A powdery extinguishing agent component is included.
The powder digestive agent according to any one of 1. 11. Powder extinguisher according to claim 1, characterized in that it comprises a thermoplastic elastic rubber in an amount of up to 30% by weight. 12. The particle size of the thermoplastic elastic rubber is 100 to 3
The powder digestive agent according to any one of claims 1 to 11, which has a diameter of 00 µm, particularly 180 to 220 µm.