COMPOSITION FOR THE MANUFACTURE OF A FOAM MATERIAL BASED ON PHENOLIC RESIN

Abstract: A composition is prepared for the manufacture of a foam material based on phenolic resin comprising components for the manufacture of a phenolic resin, acid material and carbonate containing material, in which the carbonate containing material comprises at least one element having a valency greater than one.

Description: COMPOSITION FOR THE MANUFACTURE OF A FOAM MATERIAL BASED ON PHENOLIC RESIN The invention concerns a composition for the manufacture of homogenous foamed fire resistant phenolic resin materials. The invention also concerns homogenous foamed resin materials and a method for their manufacture. In addition the invention concerns the application in mining of the foamed resin materials named in the foregoing and their components. It is known to use various blowing agents for the manufacture of fire resistant foamed materials based on phenolic resin. In the past one used principally the reaction between the carbonates and/or bicarbonates of alkali metals and acids. Halogenated hydrocarbons (R11 ; R141b: R134a) and alkanes (butane; pentane; hexane) have also been used. In order to protect the environment, halgenated hydrocarbons, which in the past have been used as the ideal chemical blowing agent, are now only permissible for special applications. Alkanes are inflammable and are therefore ill suited for applications in underground mining. From FR-A-2,686,123 a mixture for the manufacture of a phenolic resin is known which, apart from sulphonic acid as the acid component, employs sodium bicarbonate as the component for the production of carbon dioxide (blowing agent). However, alkali metal carbonates and bicarbonates, which have already been employed previously, exhibit disadvantages in use, especially with regard to underground applications. If one considers these classical carbonates, such as sodium carbonate and bicarbonate then it can be ascertained that, at least in the lower regions of the prepared foam, their use leads to an heterogeneous foam structure. Caverns the size of a fist and shrinkage are formed in the case of larger quantities of foam. In addition, at the level of foam factors which it is desired to obtain, these carbonates easily form a sediment in the starting composition because the solubility of the carbonate in the resin is exceeded. After the components have stood for an extended period the sediment, which can only be suspended again with difficulty, contains lumps which lead to problems during mechanical processing. This condition can be traced back amongst other reasons to the carbonate's tendency to crystallise. The addition of a thixotroping agent which is intended to prevent sedimentation leads to a time delay. It is especially for mining applications that one wants a product which provides the desired foaming factor, possesses a low viscosity, exhibits a long shelf life, which is dissolved or dispersed and which does not settle out. The application of a fully soluble carbonate such as potassium carbonate would be conceivable. In fact such a measure does lead to an homogeneous foam and, in the case of immediate processing, no disadvantages are caused by sedimentation of the carbonate. In this case it has been shown however that even after only one week a significant increase in the viscosity is to be noted. After two weeks processing with the usual equipment is virtually no longer possible. In this case the only possibility is to create a three component system. However this would mean having to forego the use of available machines because one would wish to work on site with a two component system. If one considers at the same time therefore the shelf life, the ability to be processed, viscosity, sedimentation behaviour and/or solubility and foam structure, then known carbonate driven 2 component phenolic resin foam systems do not offer any satisfactory solution. The task of the present invention therefore is the preparation of a product which delivers the desired foaming factor, possesses a low viscosity, exhibits a long shelf life, remains dissolved or dispersed and which does not settle out. Surprisingly it has been found that materials containing difficult to dissolve carbonate containing materials in a finely divided form, preferably precipitated carbonates and/or hydroxide carbonates, lead to an excellent foam result if they are used in a mixture for the manufacture of a phenolic resin. The problem described above is solved by the subject matter according to claim 1. Further preferred embodiments are cited in the subsidiary claims. These carbonate containing materials preferably exhibit a bulk density in the range of 1-50 wt.% of their intrinsic material density. Preferred is a value in the range of 3-30 wt.% of the intrinsic material density, in particular 9-22 wt.% but also 1-20 wt.% or 2-11 wt.%. The intrinsic material density of these materials in general lies within the range of 1.7 to 8 g/cm 3 . The particle size of the carbonate containing materials preferably lies in the range 0.05-500 μm. Preferred ranges are 0.05-10 μm, but also 1-100 μm. Preferably the carbonate containing materials exhibit a large surface area. In general this depends on the fineness of the envisaged carbonate containing material. For example, depending on origin and manufacturing methods, the ranges are 0.5-30 m 2 /g or 10-100 m 2 /g but also 0.1-10 m 2 /g. A low bulk density can preferably be achieved by a precipitation process in a manner which is itself known. The precipitation process may if necessary be facilitated by the addition of organic solvents. But grinding and other comminution processes are however also suitable. Reference is made in particular to naturally occurring carbonate containing materials which according to their structure already occur in powder form or which can be converted into powder without any great expenditure. An example is chalk. The carbonate containing materials preferably are difficult to dissolve. Their solubility at 25°C is preferably pK > 2.9, in particular pK L 3 to 20, preferred pK L 4 to 11. The carbonate containing materials used in the present invention comprise at least one element having a valency greater than one. Preferably this element is selected from elements in the main groups II. -V. of the Periodic System of Elements, the transitional group of elements and from lanthanides. Preferred are elements of main group II. in particular magnesium and/or calcium. The carbonate containing materials used in the present invention may be of natural or of synthetic origin. Examples for carbonates are CaC0 3 , MgC0 3 , SrC0 3 , BaC0 3 , CuC0 3 , CoC0 3 , FeC0 3 , ZnC0 3 , La 2 (C0 3 ) 3 OR NiC0 3 . Natural carbonates are calcite, marble, tufaceous limestone sea chalk, writing chalk, chalk calcite (Ca containing) Jurassic, tertiary, shell, Zechstein, Devonian or triascalc dolomite, dolomitic limestone (containing Ca and Mg), strontiumnite, (containing Sr) or witherite (containing Ba). Examples of hydroxide carbonates (basic carbonates) are basic magnesium carbonates e.g. MgC0 3 Mg(OH) 2 3 H 2 0 3 MgC0 3 Mg(OH) 2 3 H 2 0 and mixed forms thereof, CuC0 3 Cu(OH) 2 , 2 NiC0 3 3 Ni(OH) 2 4 H 2 0 4 NiC0 3 2 Ni(OH) 2 4 H 2 0 and mixed forms thereof, basic aluminium carbonate, basic bismuth carbonate (Bi 2 0 2 C0 3 ) or basic zirconium carbonate. The basic magnesium carbonates are preferred. Carbonate containing materials can also be used which represent an homogeneous mixture of the above named materials and/or which in addition contain a carbonate of a univalent element. Furthermore, as long as the effect as a blowing agent is not impaired, mixtures consisting of carbonates and/or hydroxide carbonates and/or hydroxides can also be used. Through the use of hydroxide carbonates and/or mixtures of carbonates with hydroxides an advantageous buffer effect is achieved for the formation of the foamed resin. The compositions named above can be employed with the usual resole resins. They are applied to substrates, which are common in mining, rock or coal. Passageways are preferably closed e.g. ventilation dams are produced. By the use of the composition according to the invention for the manufacture of foamed phenolic resin materials the following additional advantages can be achieved in comparison with the usual compositions. 1. Because of the low bulk density the carbonate containing material will be held in suspension for a long time. If it should settle out after a prolonged period then it can easily be re-dispersed because it can not dissolve and form lumps. 2. Also the low bulk density is responsible for a fine uniform distribution which leads to a uniform foam structure. 3. The presence of an hydroxide carbonate and/or a mixture of carbonate and hydroxide, buffers the acid so that the spontaneous gas evolving reaction proceeds in a controlled manner and likewise supports a uniform foam structure. 4. Because of its lack of solubility, the carbonate containing material has no injurious effect on the phenolic resin so that only the natural viscosity increase is present which thus gives a shelf life of optimum stability. 5. Because of the heat of neutralisation/condensation the foam permits a good foam result, even at low ambient temperatures. The following example explains the invention. Example A pre-mix having the following composition is prepared: Resole resin 72.0 parts by weight Water 10.5 parts by weight Flame retarding agent 11.2 parts by weight (50% aqueous potassium tri- polyphosphate) Magnesium hydroxide carbonate 72.0 parts by weight (with a bulk density of 75 g/l) Resin component A is obtained. Resin component A is mixed with acid component B. The mixing ratio of components A:B is 100:25. Acid component B consists of the following constituents: Phenol sulphonic acid 44.0 parts by weight Sulphuric acid 24.0 parts by weight Water 32.0 parts by weight The mixture which is obtained is processed by means of a two component machine in the mixing ratio reported above. A pre-foamed mixture comes out of the mixer and hardens within about 2 to 3 minutes. The foam is very homogenous and has a raw density of about 45 kg./m 3 . The stated components have a shelf life of several months.

Claims: CLAIMS 1. A composition for the manufacture of a foam material based on phenolic resin, comprising components for the manufacture of a phenolic resin, acid material, and carbonate containing material, characterised in that the carbonate containing material comprises at least one element having a valency greater than one. 2. A composition according to claim 1 in which the composition is present as a two component mixture. 3. A composition for the manufacture of a foam material according to one of the claims 1 or 2 in which the carbonate containing material in the component for the manufacture of the phenolic resin is difficult to dissolve. 4. A composition for the manufacture of a foam material according to one of the claims 1 or 3 in which the carbonate containing material comprises at least one element of the main group II of the Periodic System of Elements. 5. A composition for the manufacture of a foam material according to one of the claims 1 or 4 in which the carbonate containing material is a carbonate. 6. A composition for the manufacture of a foam material according to one of the claims 1 or 4 in which the carbonate containing material is a hydroxide carbonate (basic carbonate). 7. A composition for the manufacture of a foam material according to one of the claims 1 or 4 in which the carbonate containing material is a mixture of carbonate and/or hydroxide carbonate (basic carbonates) and/or hydroxide. 8. A composition for the manufacture of a foam material according to one of the claims 1 or 5 in which the carbonate containing material exhibits a bulk density which amounts to 1-50 wt % of the intrinsic material density of the carbonate containing material. 9. A composition for the manufacture of a foam material according to one of the claims 1 or 7 in which the carbonate containing material is a magnesium hydroxide carbonate and exhibits a bulk density within the range of 60-600 g/l. 10 A method for the manufacture of a foam material based on phenolic resin which comprises mixing the components according to one of the claims 1-9, applying the mixture onto a substrate and allowing it to harden. 11. Foam material obtained according to claim 9. 12. The use of a composition according to one of the claims 1-9 for the coating of substrates, coal and rock which are common in mining.

Inventors: BODE HARALD, KRIZANOVIC OLGA, BODE, HARALD, KRIZANOVIC, OLGA
Applicants: BODE HARALD, FOSROC INTERNATIONAL LTD, KRIZANOVIC OLGA, BODE, HARALD, FOSROC INTERNATIONAL LIMITED, KRIZANOVIC, OLGA
Application year: 1998
Main classification: C08J9
IPC codes: C08G8, C08J9, C08K3