AU667540B2

AU667540B2 - Method of implementation of sealing or filling with self-foaming phenolic resins, in particular in the field of underground mining

Info

Publication number: AU667540B2
Application number: AU41369/93A
Authority: AU
Inventors: Adolphe Weber
Original assignee: WEBER A SA
Current assignee: A WEBER SA
Priority date: 1992-01-14
Filing date: 1993-06-21
Publication date: 1996-03-28
Anticipated expiration: 2013-06-21
Also published as: ES2155831T3; AU4136993A; CZ282310B6; DE69330124T2; DE69330124D1; FR2686123A1; EP0629655B1; CZ118493A3; EP0629655A1; FR2686123B1

Description

I P/00/Oil1 w~w~~~u~iuuRegutation 3.2 667540

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

TO BE COMPLIEED BY APPLICANT Name of Applicant: A. WEBER S.A.

ActWA Inventor(s): ADOLPHE WEBER '.ddress for Service: CALLINAN LAWRIE, 278 High Street, Kew, 3101, Victoria, Australia 1.vention Title: "Method of implementation of sealing or filling with self-foaming phenolic resins, in particular in the field of underground mining" The following statement is a full description of this invention, including the best method of performing it known to me:- IL. a The present invention relates to the field of mining operations, in particular to the sealing of galleries or the consolidation of walls of mine shafts, and has for its object a method of implementation of sealing or of filling with self-foaming phenolic resins, in particular in the field of underground mining.

Within the scope of underground mining operations, and especially that of coal mining, the phenolic resins, which are well known for their resistance to fire and their weak emission of smoke, are currently widely utilised.

For this purpose, the French Patent FR-A-2 457 964 describes various phenolic resins catalysed with one or several strong acids and which expand under the influence of the evaporation of a porogenic pore generating) liquid, generally consisting of a chlorofluorohydrocarbon such as trichlorotrifluoroethane. The resin-catalyst reaction is of the exothermic type which liberates heat, causing heating and evaporation of the porogenic liquid.

However, this known foaming method and likewise other existing methods, possess a certain number of disadvantages. Actually, cold foaming, that is to say S at a temperature in the range from 1 C to 15 is impossible owing to the fact S0. that the heat of reaction is insufficient for heating the mixture, namely the resin and the catalyst, to reach the temperature required to evaporate the porogenic S liquid.

The poorly catalysed duroplast obtained from this reaction is friable and practically not expanded. In conclusion, for obtaining an acceptable foam, it is necessary to preheat the raw materials to a temperature in the range from 18 °C to or else to store said raw materials in a warm environment.

Furthermore, the resins utilised are generally applied by means of metering pumps from which the mixture of resin and catalyst issues, according to a known method, in the form of a liquid at the level of the mixing head and does not harden until after several minutes of reaction time. When the solidification has taken place, the mixture becomes heated and then, after the internal temperature has reached a value in the range from 30 C to 60 C, corresponding to the boiling point of the 3 type of porogenic liquid selected, it expands.

This method of filling cavities by foaming therefore always necessitates the use of a leak-proof casing for the purpose of avoiding the loss or the flowing-out of the materials utilised, because the expansion and the solidification is not sufficiently rapid.

Lastly, the phenolic resins which are expanded in situ and actually utilised, all employ porogenic agents based on C.F.C. which contribute to the destruction of the ozone layer and are thus to be banned within the scope of all new implementations.

Foaming methods using carbonates generally associated with C.F.C. have been attempted in the past without success.

Actually existing formulations are stated to contain three components, namely resin-carbonate-catalyst.

Other formulations necessitate continuous mixing of the resin-carbonate, to Savoid sedimentation which would result in non-uniform foaming or the absence of foaming.

These known methods cannot be used in the field of mining which necessitates the use of simple robust materials, having a regular foam structure and, in particular, consisting of formulated resols having a durability of more than several months.

The objective of the present invention is to overcome these disadvantages.

Actually, it has for its object a method of implementation of sealing or filling in that it consists of effecting a mixture of a foaming resin including sodium bicarbonate as the porogenic agent along with a catalyst containing, in particular, sulphordic acids, for the purpose carrying out, even at low temperatures, a practically instantaneous transformation into foam with a very rapid expansion rate, without requiring the setting up of a sealed leak-proof casing.

The sodium bicarbonate reacts chemically, on contact with the catalyst, with -L the sulphonic or analogous acids, to liberate carbon dioxide gas during the course of the reaction.

The gas liberated thus allows for practically instantaneous transformation of the resin-catalyst mixture into foam, no matter what the temperature of the raw materials, the chemical reaction of acid with bicarbonate being independent of the temperature.

Such a characteristic is more especially interesting in the field of underground mining, in certain cold zones, such as air adits and deeper galleries which do not permit the utilisation of phenolic foams based on owing to the fact that the temperature of the resin-catalyst mixture does not reach the evaporation temperature of the C.F.C.

Furthermore, the mixture obtained in this way can be used to produce a nonflammable foam which is not susceptible to post-combustion and the foaming mixture may be sprayed directly onto the rock, the coal or any other materials, of S which it ensures insulation against heat, gases and air.

In addition, the reaction of the phenolic resin based upon bicarbonate with the acid catalyst occurs practically instantaneously, so that the mixture issuing from the equipment used for its application foams and solidifies very rapidly, so that the construction of leak-proof casings, which is generally complicated and expensive, may be avoided, as can the loss of material by leakage during the filling of large cavities.

Another special advantage of the present invention resides in the fact that the phenolic foam, which is produced instantaneously, has an initial given volume which increases progressively until the carbonate is completely neutralised. This property, dep ".ding upon the development of a secondary expansion by gas, is very important in the field of underground mining. Actually, the primary instantaneous foaming partly fills the void, whereas the secondary expansion ensures the complete filling of the void and subjects it to pressure, thus ensuring that it is perfectly leak-proof against gas.

5 ill The foaming mixture for implementation of the method is advantageously a two-component mixture, of which the individual constituents have a life span greater than several months, and it comprises a resin consisting of a resol, of water, of sodium bicarbonate, of a thixotropic agent and of mineral fillers, and also a catalyst component consisting of phenolsulphonic acid, toluenesulphonic acid, benzenesulphonic acid, xylenesulphonic acid, sulphuric acid and water.

In order to facilitate a very rapid expansion of the foaming mixture, the sodium bicarbonate advantageously has the following particle-size distribution particle diameters up to 0.040 mm 40% to 1 0 particle diameters from 0.041 up to 0.100 mm 60% to By way of example, the two-component foaming mixture has the following preferred composition Resin component resol: 60% to water: 0% to sodium bicarbonate 5% to thixotropic agent (silica) 0.5% to 3% mineral fillers 0% to Catalyst component phenolsulphonic acid 40% to toluenesulphonic acid 10% to S benzenesulphonic acid 0% to xylenesulphonic acid 0% to sulphuric acid 10% to water: 10% to By virtue of the present invention it is possible to realise sealing or filling by means of self-foaming phenolic resins having a very rapid rate of expansion and not containing any especially in the field of underground mining.

,I

I

I 1 6 Furthermore, the method in accordance with the present invention may be implemented even at relatively low temperatures, close to 2 C, without the need for constructing sealed leak-proof casings.

Lastly, the method in accordance with the present invention may be implemented with the use of make-shift casings, that is to say, which may not be entirely leak-proof, being made from rough panels not completely sealed together, possibly with a covering of canvas which is not leak-proof, the seeping out the expanding foam through the non-sealed locations taking place only to a limited extent, largely due to the very rapid rate of expansion.

1 0 It is to be understood that the invention is not limited to the form of embodiment described in the foregoing. Modifications may be possible, especially from the point of view of the composition of the various components, without going outside the scope of protection of the invention.

4

Claims

1. A method of sealing or of filling cavities with self-foaming phenolic resins, in particular in the field of underground mining, comprising the preparation of a mixture of two components, namely a foaming resin including sodium bicarbonate as the porogenic agent and a catalyst containing especially sulphonic acids, for the purpose of achieving, even at low temperatures, a practically instantaneous transformation into foam with a very rapid rate of expansion, without the need for constructing sealed leak-proof casings.

2. A composition for use in the sealing or filling of cavities comprising; a resin component comprising a resol resin and sodium bicarbonate; and, a catalyst system; said catalyst system comprising phenclaulphonic acid, toluenesulphonic acid, sulphonic acid and water.

3. A composition as claimed in claim 2 wherein said resin component contains a thixotropic agent.

4. A composition as claimed in claims 2 or 3 wherein said resin component also contains water and/or mineral fillers. A composition as claimed in any one of claims 2 to 4 wherein the catalyst system also contains benzenesulphonic acid and/or xylenesulphonic acid.

6. A two-part mixture for use in the sealing or filling of cavities having the following composition: c

11- i- ii -8- Resin component resol: water: sodium bicarbonate: thixotropic agent (silica): mineral fillers: Catalyst component phenolsulphonic acid: toluenesulphonic acid: benzenesulphonic acid: xylenesulphonic acid: o sulphuric acid: water: DATED this 2 6 i 60% to 0% to 5% to 0.5% to 3% 0% to 40% to 10% to 0% to 0% to 10% to 10% to 1 day of JUNE 1993. A. WEBER S.A. by their Patent Attorneys: CALLINAN LAWRIE 7/ i; L ABSTRACT Method of implementation of sealing or of filling with self-foaming phenolic resins, in particular in the field of underground mining The present invention relates to a method of implementation of sealing or of filling with self-foaming phenolic resins, in particular in the field of underground mining. The method is characterised in that it consists of effecting a mixture of a foaming resin including sodium bicarbonate as the porogenic pore generating) agent along with a catalyst containing, in particular, sulphonic adds, for the purpose of carrying out, even at low temperatures, a practically instantaneous transformation into foam with a very rapid expansion rate, without requiring the S° setting up of a sealed leak-proof casing. 4 C C f v t k