GB2096622A - Process for the production of sealing and waterproofing masses based on a bituminous emulsion - Google Patents

Abstract

A process is described for the production of sealing and/or insulating bituminous masses suitable for storage and/or application as a single component, wherein at least one inorganic and/or organic fibrous filler material, a latex-containing, anion-active, stable bituminous emulsion and a clay material are used, and wherein the filler material(s) is or are dispersed or distributed in an aqueous ammonia medium the ammonia content of which 2-12 weight percent of the weight of the clay material; and wherein furthermore there are added: a) as a clay material, a K2O-containing kaolin in an amount 1 DIVIDED 3-1 DIVIDED 2the weight of the filler material(s); and b) as the latex-containing anion- active stable bitumen emulsion with a latex content (based on 100% latex dry matter) of 4-12 weight percent, in an amount 5 to 6 times the weight of the filler material; and the thus produced mass is homogenised, if so required. a

Description

SPECIFICATION Process for the production of sealing and waterproofing masses based on a bituminous emulsion The invention concerns the production of sealing and waterproofing masses based on a bituminous emulsion, which masses can be stored, break rapidly and are produced from a latexcontaining anionic bitumous emulsion with the addition of inorganic (mineral) or organic fibrous filler material.

It is known that in the production of bituminous emulsions, the properties regarded as important from the point of view of the utilisation technology can only be assured by the addition of various additives having polar or non-polar surface properties. In assuring the stability of water-insulating masses base on bituminous emulsions a great role is played by the quality of the emulsifier and the stabiliser employed. On the one hand, on storage of the finished insulating masses the stability and non-separation of the aqueous medium system must be assured while on the other hand after its application the emulsion should quickly break on the application surface and should rapidly dry in the form of a uniform continuous hydrophobic film layer.

It is also known that the stability of anionic, mainly latex-containing bituminous emulsions is deleteriously affected by the addition of fibrous filler materials because these break up the emulsion system. The filler materials play an important role in the formation of the hydrophobic film, they improve the mechanical rigidity while at the same time they cause the emulsion to be degraded and thus to separate out. Because of the filler materials the break-up of the emulsion takes place in an irreversible manner, that is to say the emulsion cannot be re-established by stirring. For this reason in the industrial practice of applying anionic bituminous emulsions, the filler is only added at the site of utilisation and for this reason the application of the mass is complicated and requires great expertise.

In the known processes, such as for instance in Patent Specification No. 54935 of the German Democratic Republic, in the normal production of aqueous bituminous emulsions bentonites which swell well in water and other various organic emulsifying agents are employed and in this way was an attempt made to increase the stability of the emulsion. The employed emulsifiers containing bentonite improve the stability of the emulsion but they have a disadvantageous effect, which is exhibited after application of the emulsion, namely they lower the water-repelling capacity (hydrophobia) of the insulating mass, and when swollen by the water may take up water in a reversible manner.The protective colloids utilised for stabilising the gel-like masses such as casein, modified carbohydrate and cellulose derivatives or synthetic polyacrylic acid esters containing free carboxyl groups, or their alkali metal or ammonium salts are either water-soluble or swell in water and therefore the hydrophobic properties of the bitumen film formed in this way are deleteriously affected. Consequently, bubbles or blisters may be formed in the bituminous layer, the insulating layer is softened, and leaks can form.

When fillers such as asbestos fibres, graphite or silica gel or silicic acid of a high degree of dispersion are added to the insulating materials based on a bituminous emulsion then the situation is further worsened because even more stabilisers need to be added to prevent the settling out of the fillers. However, in the case of adding fibrous or filamentary filling materials, even by increasing the amount of bentonite emulsifiers or modified bentonite emulsifiers, the storability of the emulsions with a gel-like consistency cannot be reliably solved.

An aim of the invention is to provide an insulating and/or sealing mass that can be applied as a single component and which consists of the combination of an aqueous dispersion containing a stably dispersed filler and an anionic bituminous emulsion to which latex has been added, which is stable in storage, does not separate or settle out, can be applied in situ after transport to the site and mild agitation, breaks quickly after application on the surface to be sealed or insulated, readily gives up its water content and after the break-up of the emulsion a continuous film layer is formed which does not exhibit water absorption, blistering or leaks.

The above aim is sought to be achieved by the use of mineral-based stabiliser(s) which is/are mixed with anion-active bituminous emulsions, homogenised and form(s) a stable gel containing more than 50% by weight of solid matter. The thus produced sealing and/or insulating masses are combinations of anion-active bituminous emulsions with additives of aqueous dispersions and latex materials.

The invention accordingly concerns a process for the production of anion-active waterinsulating or sealing masses which is as claimed in claim 1. The product can be stored for a long time and includes bitumen containing a filler and latex, wherein organic or inorganic fibrous filling material, such as asbestos fibre, mineral wool, or pulped synthetic fibres, such as polyester or polypropylene fibres, is dispersed in 2-3 times its weight of an aqueous ammonia solution to which are then added, per part of the filler material, about T to + parts of a clay e.g.

kaolin containing potassium oxide, especially ground illite, and 5-6 parts of stable anionic bitumen emulsion containing latex, expediently in several batches, and the thus formed mass is homogenised, if so required. The ground illite contains at most 5% by weight residue retained on a sieve of DIN 70 mesh; its chemical composition by weight is 50-65% SiO2, 18-31% Al203, 4-6% K20, and up to 5% Fe203, and/or up to 2% CaO and/or up to 4%MgO and/or up to 1% Na20.

A mineralogical characteristic of illite is that it is a three-layered clay mineral wherein a part of the silicon is replaced by aluminium and to bind the thus formed filler excess potassium ions are located between the planes of the lattice. If a portion of the potassium ions is exchanged for another cation, they take up water and they push the lattice planes further apart. In the course of hydration the so-called base distance between the lattice planes characteristic of illite increases from 10 A to 15-20 A and thus the illite becomes more like montmorillonite.

The ground illite is expediently allowed to swell for 24 hours before use in an equal amount of water by weight.

Preferable, the aqueous ammonia medium contains, per part of the clay material, 2.5 to 6.5 weight percent, particularly 3.5 to 5.5 weight percent ammonia.

The aqueous ammonia medium may be a 25% by volume aqueous ammonia solution of 15-25% by weight, preferably 20%, based on the weight of the ground illite; or an equivalent, larger amount of ammonia solution of lower concentration.

Preferably, the concentration of ammonia is 0.3-3.0 volume percent, more preferably 0.4-1.6 volume percent and most preferably 0.5 to 0.8 volume percent.

The latex content of the bituminous emulsion is preferably 4-10 weight percent expressed on the basis of 100% latex dry matter.

Preferably, the emulsion is produced with the aid of an emulsifier consisting of 0.1 part by weight of a water-soluble copper salt, 35-40 parts by weight of a 25 volume percent aqueous ammonia solution and 30-40 parts by weight of oleic acid or olein, and is a stable emulsion, with pH preferably adjusted to 9-10; the product containing 80-100 parts by weight of latex having a dry matter content of 60%, (or equivalent amount of latex of different dry matter content) 500-600 parts by weight of bitumen and 270 parts by weight of water.

The thus produced water-insulating mass is primarily suitable for sealing and waterproofing roofs or for repairing bituminous insulations by a single or double application. In general layers of 8-10 mm are formed. The application may take place by mechanical scattering or by manual smearing, in dependence on the size of the surface area to be protected.

According to our discovery the stability of the aqueous bituminous sealing and/or insulating mass of high dry matter content can be attributed to the fact that the potassium ions in the potassium oxide-containing kaolin, especially illite, are in part exchanged by ammonia (ammonium ions), whereupon the illite can take up water, swell and to a certain extent come to resemble montmorillonite. The possibility of rapidly exchanging the potassium ions with ammonium ions in the aqueous medium is connected with the fact that the ammonium ion is selectively adsorbed on the surfaces of the anisometric illite particles and then is integrated into the crystal lattice. However, it is assumed that only a part of the illite crystals is transformed because the diffusion into the interior of the anisometric particles takes a longer time.The intensity of the diffusion is related to the ammonium concentration of the aqueous sytem. The ammonium ions built into the crystal lattice increase the water absorption but this takes place in a reversible manner. By reducing the ammonium content of the system (and this process takes place after the application of the water-insulating mass when the ammonia evaporates in the air) the intermediate or transitional mineral product that swells similarly to montmorillonite reverts back to illite, which is less prone to water absoption. The limited swelling of the illite in the aqueous ammonia medium and the reversion of the translational mineral product to a nonswelling mineral product after the evaporation of the ammonia results in the formation of a useful waterproofing or water-insulating mass of high stability and gel-like consistency.Thus the stability of the thixotropic mass of gel-like consistency stops or ceases after application, as a consequence of the evaporation of the ammonia; rapid water loss takes place and this is a precondition of the rapid formation of the insulating layer. The limited swelling of the illite under the influence of the ammonia and its transformation after the evaporation of the ammonia is a specific phenomenon: in the case of another cation this process does not take place. An important property of the mass according to the invention is also that in the thus formed surface film layer the homogeneity is preserved, it integrates well with the original bituminous base, the number of fault locations is minimized, and the rigidity and flexiblility of the film are better as a result of the uniform distribution of the additive and filler.

The invention is further described in the following non-limiting Examples: Example 1 The sealing and/or insulating mass is made up of the following components: To prepare 1000 kg of the mass, 100 kg asbestos fibres of 3 mm fibre length are mixed for 5 minutes in a dry state, then 285 kg water and 7 kg of 25 volume percent aqueous ammonia solution are added to it. 35 kg of kaolin from Füzérradvány of the following composition is added to the amnonia solution: SiO2 content: 50-65 weight percent Al203 content: 20 weight percent Fe203 content: approx. 1 weight percent K20 content: approx. 6 weight percent Retained by sieve of DIN 70 mesh: at most 5% by weight.

In several batches 580 kg of anionic bitumen emulsion is added to this aqueous ammonia medium, taking care that the homogeneity of the mass should be maintained during this process.

If required, the whole finished mass is homogenized and with the aid of a screw pump packaged via a filling apparatus.

In place of asbesto fibre, other mineral fibrous material or pulped polypropylene or polyester fibre could be used.

The anionic bituminous emulsion was made in the following way: In a mixer 300 parts by weight of water were heated and 0.1 part by weight of copper-llsulphate (pentahydrate) was dissolved in the water under agitation. 35 parts by weight of a 25 volume percent aqueous ammonia solution were mixed with the copper sulphate solution until the colour of the solution changed from light blue to deep blue. After adding the ammonia solution 30-40 parts by weight of technical quality oleic acid was added and the solution was stirred for 30 minutes until it clarified.

Thereafter under constant stirring at 75"C 40-60 parts by weight of natural latex were added and the temperature of the aqueous phase was maintained betwwen 70-80"C. Under mixing at a high rpm 500-600 parts by weight of B-90 distilled bitumen heated to 120 C were added to the aqueous phase, taking care that during the mixing the temperature should rise no higher than 100"C. After adding the full amount of the bitumen, the emulsion was maintained under vigorous stirring until it became stable.

Example 2 The preparation of 1000 kg of sealing and/or insulating mass was carried as in Example 1, but with the difference that 580 kg of anionic bituminous emulsion was used, having the following components: Bitumen SzB-90 560 parts by weight CuSO4.5H20 0.1 part by weight 25 volume percent ammonia solution 40 parts by weight olein 40 parts by weight latex (Baypren 4R) 100 parts by weight water 270 parts by weight; and with additional difference that 40 parts by weight of kaolin was used which was pre-swelled in water in a ratio of 1:1 and which had the following composition: SiO2 content 50-65 weight percent Al203 content 20 weight percent Fe203 content 5 weight percent, and Fineness of grinding: Retained on a sieve of DIN 100 mesh at most 11 weight percent.

For the homogenization a wet grinder-sedimenter was used which consists of a coarse grinder unit and a fine grinder unit. The fine grinder unit was provided with hammer breakers provided with impact bars. The pre-ground mass was passed through an impeller mixer wherein it was passed through several filter plates of diminishing bore cross-sections and in this way the stability of the product was increased. The stability of the thus produced mass is satisfactory even after longer storage times and can be applied on site after gentle stirring for insulating purposes in the form of a sediment-free material which can be sprayed out.

Claims (10)

1. A process for the production of sealing and/or insulating bituminous masses suitable for storage and/or application as a single component, wherein at least one inorganic and/or organic fibrous filler material, a latex-containing, anion-active, stable bituminous emulsion and a clay material are used, and wherein the filler material(s) is or are dispersed or distributed in an aqueous ammonia medium the ammonia content of which 2-12 weight percent of the weight of the clay material; and wherein furthermore there are added: a) as a clay material, a K20-containing kaolin in an amount 3 the weight of the filler material(s); and b) the latex-containing anion-active stable bitumen emulsion with a latex content (based on 100% latex dry matter) of 4-1 2 weight percent, in an amount 5 to 6 times the weight of the filler material; and the thus produced mass is homogenised, if so required.

2. A process according to claim 1, characterised in that the K20-containing kaolin is ground illite.

3. A process according to claim 1, characterised in that the filler material is asbestos fibres or filaments, mineral wool and/or pulped plastics fibre, polyester fibre, polypropylene fibre, or other plastics fibre.

4. A process according to any preceding claim, characterised in that as a potassium oxidecontaining kaolin, an illite is utilized which contains 50 to 65 weight percent SiO2, 18 to 31 weight percent Al203, 4 to 6 weight K20 as well as, optionally, up to 5 weight percent Fe203 and/or up to 2 weight percent CaO and/or up to 4 weight percent MgO and/or up to 1 weight percent Na20.

5. A process according to any preceding claim, characterised in that before using the ground illite it is swelled in an equal mass of water.

6. A process according to any preceding claim, characterised in that the aqueous ammonia medium is 25 volume percent aqueous ammonia solution of 15-25 weight percent ammonia content, or an equivalent larger amount of lower amonia concentration, related to the K2O- containing kaolin, mixed with the water.

7. A process according to any preceding claim, characterised in that the aqueous ammonia medium is used in an amount 2-3 times the weight of the filler material(s).

8. A process according to any preceding claim, characterised in that as the latex-containing anion-active, stable bituminous emulsion is used which contains 40 to 100 parts by weight of latex containing 60 weight percent of dry matter, or equivalent parts by weight of latex of a different dry matter content, and 500-600 parts by weight of bitumen and 250-350 parts by weight of water, which emulsion is prepared with an emulsifier consisting of 0. 1 part by weight of a water-soluble copper salt, 35 to 40 parts by weight of a 25 volume percent aqueous ammonia solution (or an equivalent of larger weight but lower concentration) and 30-40 parts by weight of oleic acid or olein.

9. A process for the production of storable sealing or insulating masses which are applicable in a single component and are based on a bituminous emulsion, characterised in that an inorganic or organic fibrous or filamentary filler material is dispersed in 2 to 3 times its weight of an aqueous ammonia medium, to which dispersion are then added, per part by weight of filler material, on the one hand approximately Tto i parts of kaolin containing potassium oxide, especially ground illite and, on the other hand, 5 to 6 parts of latex-containing, anionic stable bituminous emulsion, and if required the thus formed mass is homogenised.

10. A process according to claim 1 or claim 9 substantially as herein described with reference to any one of the Examples.