Method of solidifying geological formations and a two-chamber charge for solidifying geological formations

Patent holder: Bayer Aktiengesellschaft, Leverkusen (Federal Republic of Germany)

The method of solidification of geological formations and a two-chamber cartridge for solidification of geological formations i

The subject of the invention is a method of solidifying geological formations and mounds of rock or earth. and

A method of solidifying geological formations and making them impermeable to water or gas is known from German Patent Specification No. 1129 894. This method consists essentially in that the formation to be sealed or solidified is forced under pressure in a liquid medium, a mixture of ^{10 * * * *} cross-linked reaction products with the -NH-CO-O- group, namely a di- or polyisocyanate, with a polyhydric alcohol having at least 3 reactive hydroxyl groups. ^{15 * * * *}

Preferred di- or polyisocyanates are tolylene diisocyanate or prepolymers of toluene bisocyanate, and towel oil or hexanetriol as polyhydroxy compounds.

However, these compounds have disadvantages that make it difficult ^{20 * *} or even prevent their use in opencast workings. Namely, toluene diisocyanate has a relatively high vapor pressure, and its vapors are harmful to the human mucosa, especially in the respiratory organs.^{23 * * * * * *}

Toluene diiaocyanate prepolymers have high viscosity and generally insufficient storage stability. They have to be used almost without exception together with liquid carriers such as solvents or plasticizers. One-³⁰ Nakże Liquid carriers lower the flash point of the mixtures and reduce the strength of the polyurethanes produced.

In order to avoid the above-described disadvantages of toluene diisocyanate, polyisocyanates which, in addition to 4,4'-diisocyanate di-phenylmethane, in particular also contain polyphenyl and polymethylene polyisocyanates, are increasingly used in the preparation of cast polyurethane resins. These polyisocyanate mixtures, referred to in the international literature as MDI-, are used for the consolidation of geological formations and heaps of rock or earth masses with the use of, e.g. in German DAS patent specification No. 2,436,029, the disadvantage that they cannot be used together with conventional polyhydroxy compounds (see Bayer AG brochure "Biaygal) Baymidur, Połyurethan-Giessharz", edition ljlil ·. 1974, page 15, column 1, last paragraph where it is necessary to mix the MDI with the polyhydroxy compounds for 3 minutes because, with too short a mixing time, it prevents separation of the mixture; see also G. Lottandi and K. Schiegg, KUnststoffe.-Plaisfics, issue 2, 1976, page; 19, column 2, section 3),

The method usually used in the preparation of polyurethane to overcome the incompatibility of MDI with polyhydroxy compounds by increasing the reactivity of the mixture with the addition of catalysts, e.g. tertiary amines or compounds

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4 metals, cannot be used for the solidification of geological formations and the erection of rock or earthen masses, because the mixture of polyisocyanate and polyhydric compound should have sufficient time before solidification or an undesirable increase in viscosity to penetrate into the crevices and pores of the formation to be solidified. Mixtures of polyisocyanates with polyols are without the addition of the aforementioned catalysts and so they can be processed in only a short time, just enough for the purpose of solidification [Stahl: Das Verfestigen des KohlenbeJins unterhalfo der Kopfstrecke in mannlosumeni Streben mit Polyiurelthąnka , issue 15, page 667, left column, close <|.

Also, the second, chemically possible way to mitigate the incompatibility of JMDI with polyols, to make prepolymers, is not suitable for solidification purposes because the prepolymers are too viscous.

It has been surprisingly found that these incompatibility problems in solidifying geological formations using "MDI" as the polyisocyanate component can be overcome if a mixture is used as the polyisocyanate component which contains 19-89% by weight of diphenyl ethane 2,4'-diisocyanate. This finding is all the more unexpected as on the one hand, as mentioned above, this incompatibility has so far been overcome by increasing the reaction capacity (addition of catalysts), and on the other hand it is known that 2,4'-diwuiiziQcyandanod) Vufenylmethane has a lower reactivity with polyhydroxy compounds than the corresponding p, p 'isglomer (German Federal Republic Patent Document No. 19231214, sheet 5, line 63 et seq.).

The subject of the invention is therefore a method of solidifying geological or earth rock masses by introducing into voids in these formations or masses of reaction mixtures based on organic compounds, polyhydroxy and organic polyisocyanates, which give polyurethanes as a result of the reaction, and a feature of this method is that , that the polyisocyanate component is a polyisocyanate mixture containing 10-80% by weight of 2,4'-diphenylmethane-diphenyl cyanide.

The subject of the invention is also a two-chamber cartridge, suitable for the application of the method according to the invention, consisting of two separate containers, one of which contains a polyisocyanate component and the other contains a polyol component, whereby the amounts of both components are selected in such a way that when the cartridge is crushed a mixture is formed which produces polyurethane by reaction. The feature of this cartridge is that it contains as a polyisocyanate component a polyisocyanate mixture of which 19 to 91% by weight is 2,4'-diphenylmethane diisocyanate.

The polyolyso-cyanide component, which is essential for the development, in a mixture with all available polyhydroxyl compounds can be introduced into fractures, voids and pores after an extremely short-lasting mixing. In the formations to be solidified, the mixtures have enough time to penetrate into the smallest branches and crevices and after when hardened, they provide very good mechanical strength, in particular, polyurethanes joining the disturbed geological formation do not show any separation pathways of the mixture components. In addition, polyurethanes made with such polyisocyanates, solidifying geological formations or heaps of rock or earth masses, have the valuable, high bonding strength of coal and rock.

The polyol component which is essential according to the invention. The cyanate is a mixture of polyisocyanates containing 19-80%, preferably 15-60% by weight of 2,4'-diisocyanatodiphenylmethane. In addition to the 2,4 'isomer, the polyisocyanate component according to the invention, a and z, usually comprises other isomeric or homologous polyisocyanates of the diphenyl meltane series. , 4^,diphenylmethane diiaocyanate and optionally 9-20% by weight based on the total amount of the mixture of 2,2 'diisocyanates or anodes in phenylmethane or else mixtures of these isomers with larger ring polyphenylpolymethylene polyisocyanates. In the case of the latter mixtures, the content of such larger ring polyisocyanates is generally from 19 to 69% by weight, based on the total amount of the mixture.

(The above-mentioned first mixture suitable as the polyisocyanate component used according to the invention can be prepared by deistylating a divisocyanate mixture of the given composition from a polyisocyanate mixture, such as that obtained by phosgenation of the analine condensation products with formaldehyde.

A mixture containing larger ring polyisocyanates, also suitable for the process according to the invention, can be prepared, for example, by grinding the above-mentioned distillation product with a phosgenatate product with a reduced content of 4,4'-di-diphenylmethane cyanate, e.g. 1 9) 20 214. Such a mixture is a mixture of polyisocyanate with a content of M 2 in diphenylmethane-diisocyanate, kept within the limits according to the invention, can be produced directly by appropriately controlling the course of the aniline-formaldehyde condensation process.

For example, U.S. Patent No. 3,2 and 77,173 teaches a process for the preparation of polyamine misaininins of the diphenylmethane series having a high content of 2,4'-diaminodiphenylylmethane. By phosgenation of such a condensation product with a high content of 2,4'-diaminodivuphenyl. the meitane can be directly prepared from polyisocyanates which are usable in accordance with the invention.

Also in the German Federal Patent Specification DOS No. 1907,686 and in the United States Patent Document the routes leading to such polyisocyanate mixtures are given. In the base, it is also possible, however not preferred, to use MDI fractions with a high content of 2,4'-dithiyaoicyainodhTUiphenylisocyanate in admixture with other polyisocyanates, e.g., toLuylene diisocyanates.

Suitable polyol components in the process according to the invention are in principle known compounds for the production of polyurethanes for other purposes, such as hydroxyl-containing polyesters or polyethers, polybasic alcohols and towel oil. Hydroxyl-containing polyethers prepared from polybasic alcohols or aimlins, e.g. such as glycerin, trimethylpropene, ethylene glycol, propylene glycol and propylene oxide with OH numbers from 50-600, as well as mixtures thereof, both include towel oil.

The quantitative ratio in which the polyol component is to be mixed with the isocyanate can vary in wide glycines, and preferably enough isocyanate is used so that there are 0.5-2% per OH group, with 0.7-1-1.6 N2 groups. ABOUT. If the geological formations or rock or earth masses to be solidified contain a lot of moisture, it is preferable to use a greater excess of isocyanate. '' '

Furthermore, it is also possible to use customary additives for modifying the polyurethanes produced, for example polyurethane additives such as water, hydrofluorocarbons, accelerators, known from polyurethane chemistry; such as tertiary amines, metallocatalysts, and foam regulators, e.g., organosilicon compounds. Water binders, such as, for example, aluminosilicate, can also be added. sodium, in the zeOlite type, to prevent foaming of the solidifying agent. This dilute is usually mixed with the polyol component. '

When using the process according to the invention, the reaction mixture, which dialyzes the polyurethane by reaction, is preferably placed in pre-drilled holes which are preferably closed after the mixture has been placed before the reaction achieves remarkable progress. Such closing of the drill hole is recommended especially when, due to the simultaneous use of water or under the influence of water ingested in the geological formation subjected to solidification, or under the influence of the organic foaming agents used, the reaction mixture foams. '^:

The polyurethane-producing reaction mixture prepared according to the invention can be introduced in various ways into the geological formation IIb <Jo of the previously drilled hole. For example, a reaction mixture can be prepared by aiming outside the geological formation and entering this forirthkiji before the reaction begins. It is also possible to introduce the polyphyphisocyanate component and the polyol component into the hole by means of pumps or by forcing it with gas, the components being mixed, for example, in a continuous mixer placed in front of the hole or in a drilled hole. ;

The process according to the invention can also be carried out particularly advantageously using a known principle

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in U.S. Patent No. 3,693,196, using a two-chamber cartridge consisting of two separate containers, one containing a half cyanide component and the other containing a polyol component. The amount of the two components is chosen so that, when the cartridge is broken up and the two components have combined, a mixture is formed which gives a polyurethane reaction. When carrying out the process according to the invention with such naibojoi, the cartridges are inserted into a pre-drilled hole and mechanically broken to mix the two components. With such a ziwośc way of proceeding. preferably jeist) when both collections work well

B agree with each other, because intensive mixing of both components after crushing the cartridge is virtually no longer possible.

The advantages of the process according to the invention are demonstrated in the examples below, in which the following reference numerals are used. ·^! and. '

Isocyanate 1 - polyisocyanate containing up to 60% by weight of 2,4'-isocyanate diphenylmethane 1 to 40% by weight 4_r4^with-dh. daily cyanidiwu. of phenytanethiain. NiCO content 32/1%, j viscosity at 25 ° C is 13 mPa.fi.

Isocyanate 2 - polyaocyanate containing up to 30% by weight of 2.4% d | wuifflocyanate dipupsnylmethane, up to 43% by weight 4,4 '<lwii »xyj £ nanod Wufenyyl meltann, up to 11% by weight of divisocyanate»¹ nophenylmethyl cyanide and up to 16 wt.% of larger ring polyphenylmethylpolyitocyanate. NICO visibility 32.0%, viscosity at 25 ° C. is 72 miPajs. r

Isocyanate 3 - polyisocyanate containing customs duty ^r 3% 2,4^/-d | visuisocyanate | wufehyk) mefanie, up to 54% 4.4^/-diisocyanatodiphenyl) ananethane, up to J and 24% dW- <isocyanatophenylylymetoto> 4isocyanatobeinze_u and up to 19% polyphenylpolymethyneopahiisocyanates. NCO content 31 $%, viscosity at tempera¹ at 25 ° C is 75 mPa.s.

Polyol 1 —> a polyester polyol made of trimethylolpropane and propylene oxide, with an OH number of 370, an average molecular weight of 450 and a viscosity of 700 m | Pa at 25 ° Cj n ¹ Rooms 2 - polyol poflaether made of glycerin and propylene oxide, OH number '410, average molecular weight 480 and viscosity

620 mPajs at 25 ° C.

Polyol 3 - towel oil, commercial product ¹ origin niatorainegio, quality grade · 1. Product of extruding with OH number = 148 and viscosity

930 mPa.s at 25 ° C. .

Polyol 4 - a polyol ether made from ethylene. diamine and propylene oxide, OH = 01,¹ an average molecular weight of 3500 and a viscosity of 630 mPa · s at 25 ° C. ·

EXAMPLE 1 For rock solidification, a mixer dosing device for processing two-component plastics is used, consisting essentially of the following parts:

A. 2 steel hoppers with a capacity of 30 liters each, capable of being closed and fed with gas and piston gas in order to establish the initial pressure. ,. . '

B. 2 reciprocating pumps; dosing with common to¹ pneumatic momentum picking up from the trays

109 455 products contained in them under pre-pressure in a volume ratio of 1: 1 and supplying these products with db of a continuous mixer »G.

C. Pass-through mixer made in the form of ⁸stationary mixer, consisting of a steel pipe 70 cm long, external diameter 9.5 mm and internal diameter 8.1 mm, with 54 baffle plates inside, evenly spaced along the pipe (Mixer [dosing device doses 2 liters in 1 minute One of the reservoirs A is filled with polyOne 1 during the entire work, to which 5% by weight of finely divided sodium aluminosilicate of the zeolite type is added with vigorous stirring. The second reservoir is filled in test 1 with isocyanate 1, in test 2 with isocyanate 2 and in test 3 with isocyanate 3.

The material to be solidified is a rock mound with a height of 20 cm, consisting of gravel with a grain size of 5 - 40 mm. In order to solidify this mound, the opening of the outlet chuck is held directly on the top layer of gravel so that the polyisocyanate-polyol mixture is pressed from top to bottom, filling the free space between the stones. The degree of solidification is assessed 5 hours after switching off the mixing dosing device.

In tests 1 and 2, the solidifying material was completely homogeneous and hard ^ while in test 3 it was soft in both the top and the lowest layer and even with a little effort it was possible to release stones with the fingers, while in tests 1 and 2 it was not possible to do so even with a lot of effort.

... Example II. Wearing places apply. a dosing device consisting essentially of the following parts:

A. 2 containers as in example I., j

B. 2; gear metering pumps with electric drives. The dosing ratio is set to the desired value. by mechanical means. gears with stepless regulation._at . C. A continuous mixer consisting of a cylindrical mixing chamber 37 mm long and 116 mm in diameter. In the axis of the chamber there is a 36 mm long finger agitator with 6 mixing blades 3 mm wide and 14 mm long.

The agitator dosing device is adjusted so as to produce a mixture that contains 1 part by volume of the cyanogen component to 1.2 parts by volume of the parenchyma component. Mixing speed is 9000 revolutions / minute and 1 L per minute is dosed in 1 minute.⁸⁰sodium-type zealite in towel oil. 1-τ3 isocyanates are used in the following sequence as polyisocyanate components.

i In order to determine the stickiness of coal and rock by the reacting polyhydrolysis mixtures, ⁸⁸ *

nu with polyol, the coal and shale are broken into prisms measuring 4X4X16 cm and placed in the mold at a distance of 2 mm between the fracture surfaces, and then the mixture of polyisocyanate with polyol discharged from the outlet of the mixing chamber is poured. After the hardening time of 8 hours, the bending strength of the glued prisms is determined according to DIN 53 452 and it is taken as a measure of the adhesive strength.¹. The test results are given in the following table.

| T ab liić a

<td></td><td>The adhesion strength of iwęgllai</td><td>iStrength of bonding, [rocks ».</td>

<td>Isocyanate and l Isocyanate 2 Isocyanate 3</td><td>1024 MiPa, 0.98 MPa 0.3 (1) MP a</td><td>3] JiO! iMPa 2.85 MPa 0.96 MPa</td>

EXAMPLE 11 A polyol mixture is prepared by measuring 100 parts by weight of Polyol 1, 25 parts of Poldol 4 and 1.2 parts by weight of 25 Water. 100 g of this mixture is mixed in a plastic vessel with 100 g of isocyanate 1 for 25 seconds after the flame of an electrically driven stirrer with 200 revolutions / minute having a mixing plate 6 cm long and wide. 2 cm bones. This mixture is poured into a downwardly inclined hole 2 cm in diameter and 50 cm deep, previously drilled in the Łu rock with a drill bit. Immediately after filling, the opening is closed with a rubber stopper S5 and after 15 hours the shale scale is broken by force using a bow pickaxe. It is found that the polyurethane foam has pressed many centimeters from the hole into the cracks of the rock, sticking it together and solidifying it. No non-uniformity is found in the polyurethane by visually and by touching the needle with the steel blade. and (By carrying out the test in an analogous manner, but using the same amount of isocyanate instead of isocyanate 1, the adhesive strength of the polyurethane foam was lower and the foam was soft.¹ ofbjszalry, incompletely hardened ha due to separation of the mixture. ...