DE1271060B - Liquid coating agent for the weatherproof closure of discontinuous surfaces in pit rooms and earthworks - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

E21f

German class: 5 d-11/00

Number: 1271060

File number: P 12 71 060.0-24

Filing date: May 4 , 1962

Opening day: June 27 , 1968

The invention relates to a liquid coating agent for the weatherproof sealing of discontinuous surfaces in pit clearing and earthworks on the basis of aqueous natural or synthetic rubber dispersions or of mixtures of such dispersions and a filler material.

In pit rooms and earthworks, especially in coal mines, there is often the risk that spontaneous heating sets in due to the entry of air into cracked and broken layers or that the heating becomes stronger or that disturbances occur in the weather management. Also can Gases, such as methane, escape through cracks in the layers into the working and conveyor lines, explosive mixtures can result and the risk of fire is increased. It is in It is highly desirable to reduce these danger points and, if possible, to eliminate them.

From British patent specification 866 804 gas-tight coatings for underground structures, such as tunnels or tunnels, are known, which can contain synthetic polymers and fillers, such as asbestos or other additives such as metal oxides, onto the surface of the Walls and subsequent drying are obtained, the liquid coating composition used containing such a component that the dried coating is flame-resistant because it releases an incombustible gas under the influence of an open flame. Such coatings are clearly inferior to the coatings obtainable according to the invention, as the comparison tests given below show.

The German Auslegeschrift 1 082 867 relates to a method for airtight and liquid-tight sealing of weather or fire dams in pits or the like, in which a rubber latex or an emulsion of a rubber-like (plastomer) natural or plastic, from which the plastomeric material is made can be easily felled, sprayed or dusted on the embankment and on the adjacent roofs, bumps and brine and the plastomeric material is precipitated immediately after the atomization. The coatings obtainable according to the above-mentioned German Auslegeschrift show a low resistance to cracks and breakage and are deformed or liquid to a considerable extent at higher temperatures. The use of aqueous natural or synthetic rubber dispersions and a fibrous filler cannot be found in the German patent application mentioned.

German Patent 915 483 relates to sprayable plastic coating and sealing compounds for application to the undersides of automobiles

Liquid coating agent

for the weatherproof closure of discontinuous

Surfaces in mining and earthworks

Applicant:

Dunlop Rubber Company Limited, London

Representative:

Dr. F. Zumstein,

Dipl.-Chem. Dr. rer. nat. Ε. Assmann
and Dipl.-Chem. Dr. R. Koenigsberger,
Patent Attorneys, 8000 Munich 2, Bräuhausstr. 4th

Named as inventor:

Reginald Royston Stapleton,

Water Orton, Warwickshire (UK)

Claimed priority:

Great Britain 6 May 1961 (16 547)

an asphalt base, for example gilsonite, which contain rubber solutions, fillers and fibers and considerable amounts of organic solvents. The coatings obtainable according to the cited German patent are completely unsuitable for the purposes of the present invention, since they are not sufficiently flexible and not sufficiently stable and contain harmful amounts of organic solvents. A coating that can be used for the present purposes must be sufficiently flexible, since coatings for sealing pit walls are often subject to considerable stresses due to earth movements. The flammability of the coatings according to the cited German patent is obvious, since the coatings contain considerable amounts of mineral oil. Since these coatings still contain 25 to 40% volatile hydrocarbons, which evaporate when they are applied, their use in pits leads to a considerable risk of explosion and damage to health. In contrast, the coatings that are obtained with the water-based coating agent according to the invention, which is explained in more detail below, have clear advantages.
The liquid coating agent according to the invention based on aqueous natural or synthetic rubber dispersions or mixtures of such dispersions and a filler material is characterized in that the filler material consists at least partially of natural or synthetic fibers with a fiber length of up to 1.27 cm, the fibers

809 567/67

in an amount between 10 and 30% of the dry matter, and a reaction product of Diphenylamine with Weights of the mass are available and the total amount of diisobutylene, which is sold under the trade name Octamine of the filler material is controlled so that the viscosity is obtainable.

the mass is between 5000 and 100000 poise. The liquid coating compositions according to the invention

All natural or synthetic 5 can be produced in any internal mixer or in any mixed rubber dispersions for the production of the invention machine, and preferred coating agents are used, since all components, with the exception of the fibers, are dispersions, which, on drying and the rubber dispersion, first result in the form of non-flammable coatings, for example poly-aqueous solutions, dispersions or slurry chloroprene, are preferred. It is known that mungen mixed with one another by io. Then the fiber graft polymerisation of a rubber latex is to be mixed in, followed by the rubber specials of a natural rubber latex with a dispersion. In the case of very viscous mixtures, it is sometimes necessary to add only part of the fiber, trichlorobromomethane, to some halogenated hydrocarbons, for example, if a dispersion is obtained, then the equivalent part of the rubber dispersion which provides a rubber whose flame-resistant properties are 15 and, in the same way, other equivalent proportions is significantly improved. Such graft poly fibers and rubber dispersion are added until the merisate dispersions contain between 20 and 70 Ge total amount has been incorporated.
percent by weight trichlorobromomethane in the graft poly- The preferred liquid merizate according to the invention and are suitable for the production of inventive coating agents are 100 parts by weight (dry) of the liquid coating agents according to the invention. 20 rubber latex with 20 to 50 parts by weight of fiber,

In the case of the liquid coating 20 to 120 parts by weight of expanding filler according to the invention, 5 to 20 parts by weight, natural fibers, such as parts by weight of metal oxide, 1 to 3 parts by weight of anti-asbestos, cotton, jute and wool, and artificial oxidants, 2 to 10 parts by weight of stabilizing agents, are used as fibers. synthetic fibers in question. To artificial agent and 0.5 to 2 parts by weight Dickungsbzw, synthetic fibers that are used kön- 25 medium mixed. The solids content of the composition can include rayon fibers, polyamide fibers such as nylon, between 40 and 70%, and is usually and polyester fibers. The fibers are each in the order of 50 to 60 ° / ο
a length of up to 1.27 cm. Asbestos fibers are preferably added The viscosity of the liquid according to the invention, with asbestos fibers, the length of which does not exceed 0.68 cm coating agent between 5000 and 100000 poise, are most suitable. As already above 30 with a viscosity between 20,000 and 50,000 poise indicated That the fibers make up 10 to 30% of the dry is preferred.

weight of the crowd. The liquid coating compositions according to the invention

The fluids according to the invention can contain delayed action coagulants or solid coating agents as well as other fillers which contain heat-sensitive coagulants and act as extenders and stiffeners. To 35 can on each porous or cracked surface be added fillers which may be used are introduced to the flow of gases to verhingehören chalk, kaolin, barite, lithopone the.

and other commonly used rubber fillers. The application of the liquid substances according to the invention. If appropriate, dyes and coating agents can also be used on such discontinuous top-coloring constituents. 40 surfaces can be cleaned with a trowel, brush, roller or spray

The liquid coating agent according to the invention are carried out with a gun. The masses can be applied, preferably containing metallic oxides of group II, in order to produce coatings with an average thickness of the periodic table of the elements, in particular 0.34 cm, which is practically zinc oxide or magnesium oxide compared to gases. The usual anti-impermeable are. Cavities and cracks in the discontinuous surface to be coated with oxidants, stabilizers and production means 45 can also be filled with the sealing compound for rubber dispersions. can be a local deposit of the mass up to the thickness

The preferred stabilizing agent is casein, made from one inch and more. To an unnecessary usually in the form of ammonium caseinate, but to prevent consumption of liquid coating compositions may also contain other stabilizing agents includ-, 50, the cavities and cracks can preferably first lent soaps with low foaming power, advertising used with wire mesh, burlap or similar Stofden. Some or all of the stabilizing agents may be covered before the coating agent is optionally used to form the desired impermeable overfill and the other additives included in the composition.
Disperse ingredients. Polyacrylates, beispiels- 55 The rubber component of the masses coagulated as ammonium polyacrylate, are the preferred due to the combined influence of dry out thickener is, but they can all On the other planning and present coagulants with verzögerren known latex thickener, such as methyl ter effect and / or heat-sensitive coagulating cellulose or gum tragacanth can be used. agents, such as zinc oxide, especially in the presence

In the liquid coating 60 according to the invention of ammonium salt. The applied coating can contain all known rubber antioxidants, in addition to or instead of a spray treatment agent, a mixture, for example with a coagulant, such as antioxidants, is preferred. Examples of a calcium chloride solution, acetic acid, or antioxidant usable are a reactive acid. It is of course possible, a diarylamine and a ketone 65 tion product by means of a spray gun, the coagulant gleichaldehyds that Avail- under the trade name BXA time to apply the liquid coating agent is hch, 2,2'-methylenebis (4-ethyl -6-t-butylphenol), the film formed is then not a continuous heterogeneous layer available under the trade name Calco 425, but consists of one

individual particles of a gelled or semi-gelled material that are weakly adhered to one another. That's why If a coagulant is used, this is preferably only applied when the liquid Coating agent has already been applied to the surface to be treated.

The coatings obtained from the liquid coating compositions according to the invention also adhere well to all of them Surfaces normally found when working underground, for example in coal mines, like on coal, stone, wood, steel and sackcloth.

When the coagulated and dried films of the liquid coating compositions according to the invention were tested for gas impermeability, it was found that they withstand the penetration of air (or other gases) when the gas is applied at a pressure which is approximately 0.035 kg / cm ² above the Atmospheric pressure. Such a pressure difference between air or other gases is greater than is usually expected from experience in underground work.

A film produced from a liquid coating agent according to the invention can easily be tested for gas impermeability be examined by z. B. the film between the flanges of two flanged together Pipes are attached and it is observed whether gas applied to one side of the film at the test pressure passes to the other side; this can be observed by placing this permeating gas in a container filled with water is filled, introduced or by any other suitable device.

The following examples serve to further illustrate the invention.

example 1

Parts Dry Moist Polychloroprene latex 100 167 12.5 ⁰ / o Ammoniumcaseinat- dispersion 5 40 50% zinc oxide dispersion 10 20th 50% BXA antioxidant dispersion 1 2 30% ^e Calco 425 Antioxydans- dispersion 1 3.3 Asbestos fibers (fibers no longer than 0.68 cm) 25th 25th 75% ig ^e Schlämmkreidedispersion 25th 33.3 15 ⁰ / oig ^e Ammoniumpolyacrylat- 1 6.7 168 297.3 Total solids 56.5%

60

The dispersions of zinc oxide, whiting, BXA, Calco 425 and ammonium caseinate are combined mixed with the ammonium polyacrylate solution in an internal mixer, and mixing continues while first the asbestos fibers and then the polychloroprene latex are added. the Compound has a viscosity of about 20,000 poise and, when sprayed and dried, gives a film,

which is substantially impermeable to air at a pressure of 0.035 kg / cm ² above atmospheric pressure.

B e i s ρ i e 1 2

A mixture is prepared as in Example 1, but with the following composition:

Parts Dry Moist 100 167 12.5% pure ^e Ammoniumcaseinat- dispersion 7.5 60 25% potassium hydroxide solution ... 0.9 3.6 50% ig ^e BXA-antioxidant dispersion 0.5 1.0 33.3% pure ^e-Octamine antioxidant dispersion 0.5 1.5 50% zinc oxide dispersion 10 20th 72% slurry chalk dispersion 100 139 Asbestos fibers (no longer than 0.68 cm) 45 45 264.4 437.1 Total solids 60.4%

A sprayed and dried film made from the mixture with the composition according to Example 2 is stiffer than the film obtained with the mixture of Example 1, but has satisfactory strength properties and is practically impermeable to air if, as described in Example 1, Is tested.

Example 3

In this example, polychloroprene latex is replaced by a chemically modified natural rubber latex replaced, on which trichlorobromomethane (T.C.B.M.) is grafted, so that it is practically non-flammable is. The mixture has the following composition:

Parts Dry Moist 70:30 natural rubber / T.C.B.M 100 167 12.5% pure ^e Ammoniumcaseinat- dispersion 2.5 20th 25% di- (2-ethylhexyl) phosphate 2.5 10 50% BXA antioxidant 0.5 1 33.3% pure ^e-Octamine antioxidant dispersion 0.5 1.5 50% antimony trioxide dispersion 25th 50 50% zinc oxide dispersion 5 10 72% slurry chalk dispersion 75 139 Asbestos fibers (no longer than 0.68 cm) 45 45 256.0 443.5 57.8 «/ ο

Example 4

A mixture is made according to the following approach:

XTU LJiCIl 100 167 Whipping chalk 25th 25th Asbestos fibers (no longer than 0.65 cm) 25th 25th 150 217 69 1%

is non-flammable and has satisfactory tensile properties.

Similar compositions are obtained when up to 100 parts of chlorinated paraffin per 100 parts by weight dry natural rubber can be used.

Example 6

A coating agent is produced which has the same composition as in Example 5, with the exception that the amount of natural rubber given in Example 5 is replaced by:

The polychloroprene latex is placed in a mixer and the dry filler powder becomes slow admitted. The resulting mixture of latex and filler then becomes the asbestos fibers added slowly so that they do not form lumps or mats.

The viscosity of the coating agent is in the range of 20,000 to 50,000 poise, and the coating is after after spraying and drying, impermeable to air in the investigation according to Example 1, not combustible and shows satisfactory tensile properties.

Example 5

A mixture is made with the following composition:

Parts Dry Moist Natural rubber latex 75 125 Styrene-butadiene copolymer 25th 42

Parts Dry Moist Natural rubber latex 100 167 Chlorinated paraffin 50 50 12.5% ammonium caseinate 5 40 50% zinc oxide dispersion 10 20th 50% BXA antioxidant dispersion 1 2 30% CaIco 425 antioxidant dispersion 1 3.3 Asbestos fibers (no longer than 0.68 cm) 25th 25th 75% slurry chalk dispersion 25th 33.3 15% ammonium polyacrylate 1 6.7 218 247.3 Total solids 62, 3%

The zinc oxide, Searm chalk, BXA, Calco 425 and ammonium caseinate dispersions and the solution of ammonium polyacrylate are mixed in an internal mixer and mixing is continued while adding first the asbestos fibers and then the chlorinated paraffin and natural rubber latex. The composition has a viscosity in the range from 5000 to 100,000 poise and, after spraying and drying, gives a film which is ^{practically impermeable to air at a pressure of 0.035 kg / cm 2} above atmospheric pressure and which makes 60 Percent by weight of the copolymer. The properties of the resulting coating are the same as in Example 5, except that the film is stiffer.

Similar coatings are obtained when the amount of styrene-butadiene copolymer rubber latex is in the range up to 50 percent by weight of the dry weight of the total rubber used and when the styrene-butadiene copolymer rubber contains styrene in amounts of 50 to 70 percent by weight of the copolymer. The following test report shows the superiority of the coatings obtained using liquid coating compositions according to the invention over the coatings obtained in accordance with British patent specification 866 804:
The three coating mixtures according to the above examples 1, 2 and 3 were compared with the sealing compounds claimed on page 2 of British patent specification 866 804 in lines 5 to 15 and 34 to 45 and in claims 5 and 9.

a) Comparison with the mass according to claim 9 of British patent specification 866 804

A dried film from this mass burned violently and was therefore completely unsuitable for Use in a pit. In addition, the film was under the pressure conditions found in a pit not flexible; the slightest attempt to bend the film under pressure gave one immediately Breakage of the film, which represents a loss of gas sealing properties.

In contrast, the three coatings according to Examples 1 to 3 of the present invention were flame resistant and flexible under pressure.

b) Comparison with the mass according to claim 5 of British patent specification 866 804

A dried film made from this mass was sufficiently fire resistant, except for a large one Area was set on fire. The material, however, was very thermoplastic, and a film underneath Tension and temperatures often found in pits stretched and broke quickly. The expansion tests carried out for comparison at elevated temperatures correspond to the pit

conditions where surface temperatures above 80 ° C often occur.

Films of 5 × 2 × 0.05 cm were produced from the mass according to British patent specification 866 804 and, in an elongation test at temperatures of 38 and 55 ° C., with corresponding films from the three coatings according to Examples 1 to 3 of the present invention compared. The films were each clamped at one end and a weight of 100 g at the lower end hanging, wherein a group of the films at 38 ° C and the other was examined at 55 ⁰ C. The films according to claim 5 of patent specification 866 804 stretched at 38 ^° C. to 400% within 4 minutes after the start of the test and then broke, while the films broke at 55 ^° C. without significant expansion within 30 seconds of the start of the test at this temperature .

In contrast, there was no measurable occurrence with the coatings according to Examples 1 to 3 of the present invention The foils stretched at 38 or 55 ° C. under these test conditions, and there was also no cracking on.

Claims (7)

Patent claims: 1. Liquid coating agent for the weatherproof sealing of discontinuous surfaces in pit rooms and earthworks based on an aqueous dispersion of a natural or synthetic Rubber, in particular a polychloroprene latex or a dispersion of a graft copolymer of natural rubber latex and trichlorobromomethane, or a mixture of such aqueous dispersions, and a filler material, preferably 1 to 3 parts by weight a rubber antioxidant, 2 to 10 parts by weight of a rubber stabilizer and 0.5 to 2 parts by weight of a rubber thickener per 100 parts (dry weight) of the Rubber dispersion are included, characterized in that the filler material consists at least partially of natural or synthetic fibers with a fiber length of up to 1.27 cm, the fibers being present in an amount between 10 and 30% of the dry weight of the mass and the total amount of filler material is controlled so that the viscosity of the mass is between 5000 and 100,000 poise. 2. Liquid coating agent according to claim 1, characterized in that the fiber consists of asbestos fibers with a fiber length not exceeding 0.68 cm in length in an amount between 20 and 50 parts by weight of the dry rubber. 3. Liquid coating agent according to claim 1 and 2, characterized by a further content a common rubber extender in an amount between 20 and 120 parts by weight 100 parts by weight of the rubber dispersion. 4. Liquid coating agent according to claim 1 to 3, characterized in that further a Group II metal oxide present in an amount between 5 and 20 parts by weight per 100 parts by weight (dry) of the rubber dispersion is. 5. Liquid coating agent according to claim 4, characterized in that the oxide of a metal Group II zinc oxide is present. 6. Liquid coating agent according to claim 1 to 5, characterized in that the total solids content between 40 and 70 percent by weight, preferably between 50 and 60 percent by weight, of the crowd. 7. Liquid coating agent according to claim 1 to 6, characterized in that the viscosity the mass is between 20,000 and 50,000 poise. Considered publications:
German Patent Nos. 915 483, 946 699;
German Auslegeschrift No. 1082 867;
British Patent No. 866,804;
"Glückauf", 1952, p. 1002. 809 567/67 6.68 © Bundesdruckerei Berlin