Grouting reinforcement material and preparation method and application thereof

Abstract

The invention provides a grouting reinforcement material and a preparation method and application thereof, and relates to the technical field of materials. Specifically, the method comprises the following steps: preparing a first mixture containing polyether polyol, a catalyst, a foaming agent, a cross-linking agent and a plasticizer; preparing a second mixture containing coal gangue, expandable graphite and polyisocyanate; the first mixed material and the second mixed material are fully mixed, and the mining grouting reinforcement material is obtained after standing and curing. The hard polyurethane grouting reinforcement material provided by the invention is simple and convenient to operate and high in safety coefficient in the application process, the coal gangue and the expansible graphite are compounded to serve as a flame-retardant filler to be modified into the polyurethane grouting material, the flame-retardant property of the material is effectively improved, and meanwhile, resource utilization of the coal gangue is realized.

Description

Technical Field

[0001] The present invention relates to the field of material technology, in particular to a grouting reinforcement material and a preparation method and application thereof. Background Art

[0002] For a long time, the energy consumption structure has been dominated by coal. However, five major disasters are common in the mining process: gas, coal dust, floods, fires, and roof accidents. These disasters pose a threat to the safety of miners and have a negative impact on the healthy development of the mining industry. In order to improve the safety of the mining process, grouting reinforcement materials can be used in this field to seal, fill, and bond the cracks and cavities in the rock and soil in the mine, consolidate the rock into blocks and form a new network skeleton structure, and effectively solve the problems of cracks and faults in the soft rock mass. It has become an effective preventive measure. Polyurethane grouting materials suitable for underground reinforcement and fire prevention in coal mines have the advantages of simple operation, good adhesion, corrosion resistance, and good aging resistance. They can be used to fill cracks or cavities in tunnels, wrap mine pipes, reinforce broken rock layers, seal water seepage channels, and make lightweight false roofs in goafs to reduce surface subsidence. Polyurethane grouting materials have outstanding performance in terms of efficient support, energy conservation and environmental protection. However, their limiting oxygen index is less than 27, making them flammable materials. When a fire occurs, they will burn rapidly and release large amounts of heat and toxic smoke, increasing the danger on site.

[0003] Gangue is a solid waste generated during the mining and washing of coal. With the mining of coal, the amount of gangue is also increasing. Large-scale storage or landfill not only occupies land, but also causes environmental pollution, and the actual utilization efficiency is insufficient. The main chemical components of gangue include SiO2, Al2O3, Fe2O3 and a small amount of alkali metal oxides, and it is expected to be used as an inorganic filler to improve the matrix material. For example, patent application number 202311250218.8 discloses a method for preparing a gangue / polyurethane grouting composite material. The surface of the gangue powder is modified by a silane coupling agent, and the modified gangue powder is added to the polyurethane grouting material as a filler, thereby reducing the cost of the grouting material while ensuring that the composite grouting material still has a sufficiently high compressive strength. The grouting composite material obtained in this patent has a compressive strength of more than 40MPa within 24 hours. However, it still does not mention the flame retardant performance defects of the polyurethane.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The first purpose of the present invention is to provide a preparation method of a grouting reinforcement material, which is used to solve the defects of traditional polyurethane grouting reinforcement materials in terms of flame retardant performance, and to provide a new resource application path for coal gangue in an expansive way.

[0006] The second object of the present invention is to provide a grouting reinforcement material.

[0007] The third object of the present invention is to provide the use of the grouting reinforcement material in the mining field.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are adopted:

[0009] A method for preparing a grouting reinforcement material comprises the following steps:

[0010] Prepare a first mixed material comprising polyether polyol, catalyst, foaming agent, cross-linking agent and plasticizer; prepare a second mixed material comprising coal gangue, expandable graphite and polyisocyanate;

[0011] The first mixed material and the second mixed material are fully mixed, and after standing and solidifying, a mining grouting reinforcement material is obtained.

[0012] A grouting reinforcement material comprises a material prepared by the preparation method of the grouting reinforcement material.

[0013] And the application of the grouting reinforcement material in mining.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) The present invention provides a grouting reinforcement material and a preparation method thereof, specifically, a polyurethane grouting reinforcement material based on a composite modification of coal gangue and expandable graphite and a preparation method thereof; the material of the present invention achieves excellent flame retardant properties based on inorganic modification, and achieves the advantage of low cost by combining with waste recycling.

[0016] (2) When the grouting reinforcement material of the present invention is used in coal mines or ore mining, it has the advantages of short material curing time, convenient operation, and greater safety for operators and the environment; and when there is a fire safety hazard, the grouting reinforcement material of the present invention has lower toxic gas release after combustion and a high amount of residual carbon; the limiting oxygen index of the composite grouting material obtained by testing is greater than 30, which meets the coal mine safety production standards and effectively improves the flame retardant properties of the composite material. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments, but those skilled in the art will understand that the following embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially. In addition, the terms "one", "two", and "1" are only used for descriptive purposes and should not be interpreted as indicating or suggesting relative importance.

[0018] The first aspect of the present invention is to provide a method for preparing a grouting reinforcement material, which mainly includes the following steps: preparing a first mixture containing polyether polyol, a catalyst, a foaming agent, a cross-linking agent and a plasticizer; preparing a second mixture containing coal gangue, expandable graphite and polyisocyanate; fully mixing the first mixture and the second mixture, and obtaining a mining grouting reinforcement material after standing and curing.

[0019] As a preferred embodiment, the coal gangue mainly includes the following components by mass percentage: SiO2 45% to 65%, Al2O3 15% to 28%, Fe2O3 7% to 15%, TiO2 <4%, MgO <5%, CaO <4%, K2O <8%, and low content of sulfur, chlorine oxides or oxygen-containing salts, and other inevitable impurities.

[0020] As a preferred embodiment, the fineness of the coal gangue is 0.05 mm to 0.1 mm, including but not limited to any one of 0.05, 0.055, 0.06, 0.065, 0.7, 0.075, 0.08, 0.085, 0.09, 0.095, and 0.1 (mm), or a numerical range consisting of any two thereof. In the present invention, the coal gangue raw material needs to be finely ground and screened in advance before using the coal gangue of appropriate fineness as the filling material for the polyurethane gaps. Otherwise, it will be difficult to achieve both the mechanical properties and flame retardant properties of the reinforcement material.

[0021] In some optional embodiments, the gangue is pre-treated by grinding using equipment such as a ball mill, a vibration mill, a stirred mill, a jet mill, a pressure roller mill or a ring roller mill, and then sieved through a sieve to obtain the raw material of the gangue suitable for the above-mentioned fineness range.

[0022] In addition to solving the resource utilization channel of the coal gangue, the present invention also involves another inorganic filling material "expandable graphite"; it is a green intumescent flame retardant. After this material expands when heated, it will form a worm-like carbon layer, which effectively prevents the spread of flames. However, when used alone as a modified material for grouting materials in the mining field, it is easy to produce a "popcorn effect", resulting in damage to the structure of cracks and cavities in the rock and soil body, and easily causing instability of the filling layer.

[0023] In the present invention, by synergizing coal gangue and expandable graphite as inorganic modified fillers for polyurethane grouting reinforcement materials, on the one hand, the disadvantages of the flame retardant properties of the polyurethane reinforcement material itself can be effectively solved, and on the other hand, instability in the mechanical properties of the polyurethane reinforcement material during the high-temperature flame retardant process will not be caused.

[0024] As a preferred embodiment, the particle size of the expandable graphite is 70-90 mesh. In some more preferred embodiments, the expansion multiple of the expandable graphite is 180-220, and the carbon content of the expandable graphite is 95%±2%.

[0025] As a preferred embodiment, the mass ratio of the coal gangue to the expandable graphite is 1:4 to 4:1, including but not limited to any one of 1:4, 1:3, 1:2, 1:1, 2:1, 2:3, 3:1, 3:2, 3:4, 4:1, 4:3, etc., or a numerical range consisting of any two of them.

[0026] As a preferred embodiment, the ratio of the sum of the mass of the gangue and the expandable graphite to the sum of the mass of the first mixture and the polyisocyanate is 10% to 15%, including but not limited to any one of 10%, 10.5%, 11%, 11.5%, 12%, 12.5%, 13%, 13.5%, 14%, 14.5%, and 15%, or a numerical range consisting of any two of them.

[0027] It can be understood that the total amount of the inorganic modified material used to enhance the flame retardant properties in the present invention should be within the above-mentioned distribution coefficient range and total amount range, on the one hand to avoid the reduction of the mechanical properties of the reinforcement material when the modified material is excessive, and on the other hand to avoid the reduction of the mechanical properties of the reinforcement material when the amount of a certain component in the coal gangue or expandable graphite is too high.

[0028] As a preferred embodiment, the polyether polyol includes at least one of polyether polyol 4110, polyether polyol 330N, or polyether polyol 3628. Those skilled in the art will appreciate that these polyether polyols correspond to the commonly used commodity categories in the industry. Furthermore, the present invention utilizes a trifunctional series of polyether polyols. These three polyether polyols offer varying performance advantages. For example, polyether polyol 4110 yields a grouting reinforcement material with higher mechanical strength and aging resistance, while polyether polyol 330N exhibits improved toughness.

[0029] As a preferred embodiment, the polyisocyanate includes at least one of MDI or PAPI; wherein MDI is diphenylmethane diisocyanate, and PAPI is polymethylene polyphenyl polyisocyanate.

[0030] As a preferred embodiment, the catalyst includes an organotin catalyst, including but not limited to DBTDL (dibutyltin dilaurate), T-9 (stannous octoate), DBTDA (dibutyltin diacetate), DBTM (dibutyltin maleate), etc.

[0031] As a preferred embodiment, the foaming agent includes at least one of n-pentane, cyclopentane or isopentane; due to the volatility of the above-mentioned physical foaming agent in the polymerization reaction system, the foaming agent is heated and vaporized during the process of generating the polyurethane material, forming a large number of tiny bubbles in the polymer matrix, thereby forming expansion foaming.

[0032] As a preferred embodiment, the cross-linking agent includes at least one of glycerol, triethanolamine, trimethylolpropane, pentaerythritol or castor oil; the cross-linking agent introduces additional reactive sites to form chemical bonds between the molecular chains of the polyurethane material, thereby improving the performance of the polyurethane reinforcement material.

[0033] As a preferred embodiment, the plasticizer includes at least one of DOP (dioctyl phthalate), DOTP (dioctyl terephthalate), ATBC (acetyl tributyl citrate) or TOTM (trioctyl trimellitate); the plasticizer is inserted between the polyurethane molecular chains, weakening the interaction force between the molecular chains and reducing the crystallinity of the molecular chains, thereby making the polyurethane material soft and improving its processing properties, such as reducing the melt viscosity, to facilitate molding operations such as extrusion and injection molding.

[0034] As a preferred embodiment, the molar ratio of the polyether polyol to the polyisocyanate is (1-1.2):1.

[0035] As a preferred embodiment, based on the total amount of the polyether polyol and the polyisocyanate used, the ratio of the catalyst to the total amount is 0.5% to 2%, the ratio of the foaming agent to the total amount is 5% to 10%, the ratio of the crosslinking agent to the total amount is 2% to 8%, and the ratio of the plasticizer to the total amount is 3% to 8%.

[0036] As a preferred embodiment, the mass ratio of the first mixed material to the second mixed material is (0.8-0.95):1.

[0037] As a preferred embodiment, during the preparation process of the first mixture and the second mixture, as well as the thorough mixing, oscillation, stirring, shaking, centrifugation, heating and the like can be independently selected to assist in the process, which helps to accelerate dispersion and obtain a relatively uniform dispersion system.

[0038] It should be noted that the specific implementation steps and equipment of the preparation and the thorough mixing are not specifically limited. In some more preferred embodiments, mechanical stirring can be used. For reference, the stirring frequency in the preparation of the first mixture is 500 rpm to 800 rpm, and the stirring frequency in the preparation of the second mixture is 800 rpm to 1200 rpm; the stirring frequency in the thorough mixing is 600 rpm to 1500 rpm, and the stirring time is 20 min to 120 min.

[0039] As a preferred embodiment, the ambient temperature for static curing is 70°C to 90°C, and the static curing time is 3h to 5h; in some optional embodiments, the ambient temperature for static curing includes but is not limited to 70, 72, 75, 78, 80, 82, 85, 88, 90 (°C), and the static curing time includes but is not limited to any one of 3, 3.2, 3.5, 3.8, 4, 4.2, 4.5, 4.8, 5 (h) or a numerical range composed of any two of them.

[0040] In the present invention, after obtaining a relatively uniform mixture, it is necessary to store it at a specific ambient temperature for a certain period of time to realize the synthesis reaction of polyurethane. On the one hand, when the temperature is too low, the molecular thermal motion is not obvious enough, so it can only be compensated by the reaction time, which reduces the production efficiency of the grouting material. On the other hand, when the molecular activity and molecular thermal motion are too high, there may be evaporation or failure of the raw materials, or waste of heat resources. Therefore, the conditions for static curing are limited to the above range.

[0041] As a preferred embodiment, before the static solidification, the method further includes: pouring the fully mixed mixture of the first mixture and the second mixture into a mold, thereby obtaining the grouting reinforcement material of a preset volume or shape.

[0042] A second aspect of the present invention is to provide a grouting reinforcement material, comprising a material produced by the method for producing a grouting reinforcement material as described in the first aspect. It is understood that the grouting reinforcement material described in this aspect may be produced solely by the method described in the first aspect, or may additionally include other reinforcement materials in addition to the material produced by the method described in the first aspect.

[0043] The third aspect of the present invention is to provide use of the grouting reinforcement material according to the second aspect in mining.

[0044] The following examples or comparative examples of the present invention all use coal gangue from the same source with the chemical composition shown in Table 1.

[0045] Table 1 Composition of coal gangue

[0046]

[0047] Example 1

[0048] (1) The coal gangue was crushed, ground and sieved to obtain coal gangue fine powder with a fineness of 0.074 mm, and the fine powder was mixed with expandable graphite (80 mesh, expansion multiple 200, carbon content 95%) in a mass ratio of 1:1 to obtain a modified filler.

[0049] (2) 60 parts by weight of polyether polyol 4110, 1 part by weight of catalyst (dibutyltin dilaurate), 5 parts by weight of foaming agent (cyclopentane), 3 parts by weight of crosslinking agent (triethanolamine), and 3 parts by weight of plasticizer (dioctyl phthalate) were stirred and mixed at room temperature and 600 rpm until uniform, to obtain component A.

[0050] (3) The modified filler obtained in step (1) and polyisocyanate (diphenylmethane diisocyanate) were stirred and mixed at a mass ratio of 0.15:1 at room temperature and 1000 rpm until uniform, to obtain component B.

[0051] (4) Component A and component B were quickly stirred and mixed at a mass ratio of 1:1 when the modified filler was not included, and after injection molding, the mixture was allowed to stand and cure at 80° C. for 4 hours to obtain the coal gangue / expandable graphite grouting composite material of this embodiment.

[0052] Example 2: is basically the same as Example 1, except that in step (1), the mass ratio of coal gangue to expandable graphite is 1:4.

[0053] Example 3: is basically the same as Example 1, except that in step (1), the mass ratio of coal gangue to expandable graphite is 4:1.

[0054] Example 4: is basically the same as Example 1, except that in step (3), the modified filler and the polyisocyanate are mixed in a mass ratio of 0.1:1.

[0055] Example 5: is basically the same as Example 1, except that the type of polyether polyol is replaced by polyether polyol 4110 (number average molecular weight is 600), and the polyisocyanate is replaced by PAPI.

[0056] Example 6: is basically the same as Example 1, except that the foaming agent is replaced by n-pentane, the cross-linking agent is replaced by glycerol, and the plasticizer is replaced by trioctyl trimellitate.

[0057] Comparative Example 1: basically the same as Example 3, except that step (1) is eliminated and no modified filler is added in step (3).

[0058] Comparative Example 2: basically the same as Example 4, except that step (1) is eliminated and no modified filler is added in step (3).

[0059] Comparative Example 3: The process is basically the same as Example 1, except that the modified filler in step (3) is replaced with 0.074 mm coal gangue fine powder.

[0060] Comparative Example 4: is basically the same as Example 1, except that the modified filler in step (3) is replaced by expandable graphite.

[0061] Test example

[0062] The flame retardant properties of the polyurethane grouting composite materials prepared in the above embodiments and comparative examples were tested, and the results are recorded in Table 2. The specific testing method is as follows:

[0063] 1) Fifteen samples of the composite material for detection of limiting oxygen index in each example were prepared, each with a size of 150 mm × 10 mm × 10 mm. The loss on ignition (LOI) was tested according to the standard GB / T2406.2-2009. A TA SDT-Q600 thermogravimetric analyzer was used, with a sampling rate of 5 to 10 mg. The test temperature range was 30°C to 850°C, the protective gas was air, and the flow rate was 30 mL / min. The thermogravimetric carbon residue was calculated.

[0064] 2) Prepare three composite material samples in each example, all with dimensions of 100 mm × 100 mm × 3 mm. Test according to standard GB / T 16172 using a British FTT0007 cone calorimeter to measure the ignition time and combustion heat release of the sample material (the data are averaged over three times).

[0065] Table 2 Flame retardant performance test results

[0066]

[0067] Although the present invention has been illustrated and described using specific embodiments, it should be appreciated that the above embodiments are merely intended to illustrate the technical solutions of the present invention rather than to limit them. Those skilled in the art should understand that the technical solutions described in the above embodiments may be modified, or some or all of the technical features thereof may be replaced by equivalents, without departing from the spirit and scope of the present invention. However, these modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments of the present invention. Therefore, this means that all such replacements and modifications within the scope of the present invention are included in the appended claims.

Claims

1. A method for preparing a grouting reinforcement material, characterized in that: The steps include: Prepare a first mixed material comprising polyether polyol, catalyst, foaming agent, cross-linking agent and plasticizer; prepare a second mixed material comprising coal gangue, expandable graphite and polyisocyanate; The first mixed material and the second mixed material are fully mixed, and after standing and solidifying, a mining grouting reinforcement material is obtained.

2. The preparation method according to claim 1, characterized in that The fineness of the coal gangue is 0.05mm to 0.1mm; And / or, the particle size of the expandable graphite is 70 mesh to 90 mesh.

3. The preparation method according to claim 1, characterized in that Includes at least one of the following features (A) to (F): (A) the polyether polyol comprises at least one of polyether polyol 4110, polyether polyol 330N, or polyether polyol 3628; (B) the polyisocyanate comprises at least one of MDI or PAPI; (C) the catalyst comprises an organotin catalyst; (D) the blowing agent comprises at least one of n-pentane, cyclopentane or isopentane; (E) the cross-linking agent comprises at least one of glycerol, triethanolamine, trimethylolpropane, pentaerythritol or castor oil; (F) The plasticizer includes at least one of DOP, DOTP, ATBC or TOTM.

4. The preparation method according to claim 1, characterized in that The ratio of the sum of the mass of the gangue and the expandable graphite to the sum of the mass of the first mixed material and the polyisocyanate is 10% to 15%; And / or, the mass ratio of the first mixed material to the second mixed material is (0.8-0.95):

1.

5. The preparation method according to claim 1, characterized in that The molar ratio of the polyether polyol to the polyisocyanate is (1-1.2):

1.

6. The preparation method according to claim 1, characterized in that The mass ratio of the coal gangue to the expandable graphite is 1:4 to 4:

1.

7. The preparation method according to claim 1, characterized in that The ambient temperature for the static curing is 70° C. to 90° C., and the time for the static curing is 3 hours to 5 hours.

8. The preparation method according to claim 1, characterized in that The following steps are also included: The fully mixed mixture of the first mixed material and the second mixed material is poured into a mold, and is allowed to stand and solidify to obtain the grouting reinforcement material.

9. A grouting reinforcement material, characterized in that: The invention comprises a material prepared by the method for preparing the grouting reinforcement material according to any one of claims 1 to 8.

10. Use of the grouting reinforcement material according to claim 9 in mining.

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