JP2000080355A - Coating composition for protecting outdoor piled coal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating composition for protecting outdoor piled coal from quality deterioration, spontaneous ignition, dust-making, loss by outflow, lowering of workability and the like and a method therefor. SOLUTION: A water dispersible resin, for example, a polyurethane resin in an emulsion form and a water repellent, for example, a natural or synthetic wax are dispersed in water in a solid content ratio of 100/1-100/50 to give a coating composition. This composition is applied to the exposed surface outdoor piled coal at a spread of at least 0.01 kg/m2 to form a continuous film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an increase in the moisture content of open coal stored in power plants, steelworks, factories using coal, coal distribution bases, mines, etc., flowing coal, dust, reduced coal, and adhesion. -It relates to a coating composition for protecting from clogging, oxidative deterioration and spontaneous ignition.

[0002]

2. Description of the Related Art Normally, a large amount of coal is stored in a pile at a power plant, a steel mill, a factory using coal, a coal distribution base, a mine, and the like. Such open stack coal is
It has various problems such as rising water, flowing coal, dust, reducing coal, sticking / clogging, oxidative deterioration and spontaneous combustion.

[0003] Fine coal dust is scattered by the wind and deteriorates the working environment and the surrounding environment, and the deposited coal is washed away due to rainfall, and the amount of deposited coal is reduced or the deposited state is collapsed. And spend considerable time and effort re-depositing. Furthermore, if the piled coal mine absorbs rainwater or the like, the evaporation loss of water occurs when burning coal having an increased water content or when producing coke.

[0004] In addition, if the coal is left for a long period of time, the flow of air into the coal sediment causes an oxidation reaction of the coal, and the heat of the reaction accumulates, causing a problem that spontaneous ignition of the coal occurs. There is also.

[0005] At the time of coal transfer, clogging of a hopper due to coal adsorption due to moisture on the surface of the coal, or adhesion at a handling facility such as a belt conveyor has become a problem.

[0006] Conventionally, various proposals have been made as these remedies. For example, use of a surfactant to prevent dust as disclosed in JP-A-57-98579, or JP-A-2-29
2390 adhesion, blockage prevention, JP-A-59-226095
For preventing a rise in water due to the use of asphalt emulsions, the combined use of a vinyl polymer emulsion and a surfactant described in JP-A-2-88695, or JP-A-5-2304.
Methods for preventing spontaneous ignition and dust generation by using 80 water-absorbing synthetic resins have been proposed.

However, the method using a surfactant has a problem that not only the surfactant is washed away by rain but the effect is lost, but also the surrounding environment is polluted.

Further, vinyl acetate polymers, acrylic acid polymers and SBs conventionally used as film-forming agents have been used.
In the method using an aqueous emulsion such as R rubber latex, not only the wettability on the coal surface is insufficient and a uniform film cannot be formed, but also the water repellency of these films is poor and the strength is insufficient. Cracks are remarkable, especially moisture rise,
Not fully satisfactory as coal and dust prevention.

In order to solve the above-mentioned drawback of wettability, it has been proposed to use an aqueous emulsion of various polymers in combination with a surfactant. However, by using a surfactant together, the film strength of these film-forming agents can be improved. Is remarkably reduced, so that the cracks in the film are remarkable and have not yet been sufficiently satisfied.

[0010]

Accordingly, there is a need for a method of protecting open coal and a protective coating composition therefor that can overcome the disadvantages of the previously proposed methods.

[0011]

SUMMARY OF THE INVENTION The present invention provides a coating composition for protecting open-pile coal from quality deterioration, spontaneous ignition, dust generation, spill loss, reduced workability, and the like. This composition comprises a water-dispersible resin dispersed in water and a water repellent at a solid content ratio of 1
It is contained in the ratio of 00/1 to 100/50. Preferred water dispersible resins are polyurethane resins in the form of an emulsion, and preferred water repellents are natural or synthetic waxes.

The present invention also provides the coating composition of the present invention as a solid content of 0.01 kg /
to provide a protection method consists in applying in m ² or more amounts. Preferably, the coating composition is applied to the exposed surface of the piling coal pre-moistened with water, and the coating composition is preferably applied at least in two portions.

[0013] The applied coating composition forms a continuous film over the exposed surface of the coal pile. Preferably, the film exhibits a contact angle with water of at least 70 ° in the dry state and a tensile strength of 10 kg / cm ^{2 in} the wet state.

[0014]

[Requirements Constituting Means] Main requirements relating to the configuration of the invention will be described below.

Water-dispersible resins Examples of water-dispersible resins include vinyl acetate resin, ethylene vinyl acetate resin, alkyd resin, acrylic resin, acrylamide resin, natural rubber, synthetic rubber, petroleum resin, vinyl chloride resin, and styrene butadiene. Resin, acrylonitrile butadiene resin, methacrylate butadiene resin, styrene resin, polyester resin, polyurethane resin and the like. These resins can be used alone or
You may mix and use more than one type.

Of these, a polyurethane resin which forms a tough and flexible film at room temperature is particularly preferred.

Water repellent The water repellent used in the present invention in combination with the water-dispersible resin is:
It is added to make the contact angle of water of the dried film 70 ° or more.

Examples of the water repellent include natural waxes and synthetic waxes of plant type, animal type, mineral type, petroleum type, etc., and silicon type and fluorine type compounds. In the wax system,
In particular, polyolefin, polyethylene, polyethylene oxide, polypropylene, ethylene / acrylic acid copolymer, ethylene / vinyl acetate copolymer, paraffin,
Montan type, microcrystalline type, petrolatum type and the like. These water repellents may be used alone or in combination of two or more.

Of these, it is more preferable to use a paraffinic, microcrystalline, or petrolatum-based compound alone or in combination of two or more, which forms a flexible film and has good wettability with coal.

Compounding ratio of water-dispersible resin / water-repellent The compounding ratio of the water-dispersible resin and the water-repellent used in the present invention is 100/1 to 100/50 in terms of solid content ratio. The water-dispersible resin alone is insufficient in water repellency, and cannot prevent flowing coal and rise in coal moisture particularly during rainfall, and cannot satisfy the object.

In order to form a resin film having excellent water repellency on the coal surface, the mixing ratio of the water-dispersible resin and the water repellent must be 100/1 or more in terms of solid content.

However, if the water-repellent is added more than necessary, the strength of the resin film is extremely reduced due to the plasticizing effect of the water-repellent. As a result, problems such as contamination of the surrounding environment occur. Therefore, the mixing ratio of the water-dispersible resin and the water repellent is preferably in a range not exceeding 100/50 of the solid content ratio. A more suitable mixing ratio of the water-dispersible resin and the water-repellent for coating the coal surface with a tough resin film having excellent water repellency is a solid content ratio of 100/5 to 100/30.

The method of blending the water repellent used in the present invention may be a method of mixing a water-repellent emulsion type with a water-dispersible resin, or a water-repellent base material or a water-repellent before dispersion of the resin. A method in which a liquid agent emulsion is mixed with a urethane prepolymer and then emulsified is used.

Film Contact Angle and Wet Tensile Strength The dry film formed from the blend of the water-dispersible resin and the water repellent used in the present invention preferably has a water droplet contact angle of 70 ° or more. 80 to further develop the water repellent effect
° or more is more preferable.

The film formed from the blend of the water-dispersible resin and the water repellent used in the present invention has a tensile strength at wet of 1
It is preferably at least 0 kg / cm ² . If the tensile strength is low, cracks tend to occur on the coal surface during rainfall.
Wet tensile strength 1 to further prevent cracks on the coal surface
5 kg / cm ² or more is more preferable.

Aqueous polyurethane resin dispersion is prepared by reacting two or more active hydrogen atom-containing polyhydroxy compounds with an organic polyisocyanate compound having two or more isocyanate groups. It is obtained by emulsifying an NCO group-containing urethane prepolymer in water and then elongating the chain with a polyvalent amine compound or water. The urethane prepolymer is classified as follows according to the emulsification method.

(1) Two or more active hydrogen atom-containing polyhydroxy compounds, organic polyisocyanates, and N
Using a salt-forming agent, an NCO-group-containing urethane prepolymer synthesized from a compound having an active hydrogen atom and a salt-forming group reactive with a CO group is emulsified in water, and then chain-extended with a polyamine compound or water. Or cationic polyurethane resin aqueous dispersion obtained by

(2) NCO group-containing urethane prepolymer synthesized from two or more active hydrogen atom-containing polyhydroxy compounds, organic polyisocyanates, and mono- or polyhydric alcohol ethylene oxide alone or ethylene oxide and propylene oxide adducts. A nonionic polyurethane resin aqueous dispersion obtained by emulsifying a polymer in water and then chain extending with a polyvalent amine compound or water

(3) An NCO group-containing urethane prepolymer synthesized from two or more active hydrogen atom-containing polyhydroxy compounds and organic polyisocyanates is converted into water by using a surfactant such as an anion, cation, or nonionic. Polyurethane resin aqueous dispersion obtained by forced chain emulsification and chain elongation with polyvalent amine compound or water

(4) a polyhydroxy compound containing two or more active hydrogen atoms, an organic polyisocyanate, and N
An NCO group-containing urethane prepolymer synthesized from a compound having an active hydrogen atom and a salt-forming group reactive with a CO group is emulsified in water by using a salt-forming agent and a surfactant such as an anion, cation, or nonionic. Thereafter, a polyvalent amine compound or an aqueous dispersion of an anionic or cationic polyurethane resin obtained by chain elongation with water may be used.

Raw Materials for Use of Polyurethane Resin Dispersion Examples of the raw materials for use in the aqueous polyurethane resin dispersion used in the present invention include the following.

Active Hydrogen Atom-Containing Polyhydroxy Compound:
Examples of the polyhydroxy compound having two or more active hydrogen atoms in a molecule used in the present invention include ethylene glycol, diethylene glycol, butanediol, propylene glycol, polypropylene glycol, hexanediol, bisphenol A, bisphenol S, and hydrogenated bisphenol. A, dibromobisphenol A, 3
Polyhydric alcohols such as -methyl-1,5-pentanediol, 1,4-cyclohexanedimethanol, dihydroxyethyl terephthalate, hydroquinone dihydroxyethyl ether, trimethylolpropane, glycerin, polypropylene glyceride, and pentaerythritol;
Ester compounds from those alkylene derivatives or their polyhydric alcohols or their alkylene derivatives and polycarboxylic acids, polycarboxylic anhydrides, or polycarboxylic esters, polycarbonate polyols,
Polytetraethylene glycol, polycaprolactone polyol, polybutadiene polyol, olefin-based polyol, polythioether polyol, polyacetal polyol, castor oil polyol, castor oil derivative,
Examples include polyol compounds such as rosin and dimer acid.

Polyvalent amine compound: As the polyvalent amine compound used in the present invention, a compound having two or more amine groups is used. For example, ethylenediamine, propylenediamine, diethylenetriamine, hexylenediamine, triethylenetetramine, tetraethylene Examples include ethylenepentamine, isophoronediamine, xylylenediamine, diphenylmethanediamine, hydrogenated diphenylmethanediamine, and hydrazine.

Organic polyisocyanate compound: The organic polyisocyanate compound having two or more isocyanate groups in a molecule used in the present invention includes tolylene diisocyanate, diphenylmethane diisocyanate, and the like.
Xylylene diisocyanate, naphthylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated toluene diisocyanate, tetramethylene xylylene diisocyanate, and buret compounds and isocyanurate compounds of these isocyanates have been conventionally used. All aromatic, aliphatic and cycloaliphatic isocyanates can be used alone or as a mixture.

Further, those obtained by the addition reaction of these isocyanates with a polyvalent hydroxy compound such as trimethylolpropane are also included.

Compounds having a salt-forming group and corresponding salt-forming agents: The compounds having an active hydrogen atom reactive with an NCO group and a salt-forming group and the corresponding salt-forming agents used in the present invention include: . Compounds having a salt-forming carboxylic acid or sulfonic acid group and corresponding salt-forming agents b. A compound having a group that can be a quaternary or tertiary group that can be neutralized with an acid, and a corresponding salt-forming agent; c. Examples include compounds containing a halogen atom or a corresponding strong acid ester that causes a quaternization reaction, and corresponding salt-forming agents.

Examples of the compound having a salt-forming carboxylic acid or sulfonic acid group include hydroxy acids such as glycolic acid, malic acid, glycine, aminobenzoic acid, alanine, dimethylolpropionic acid, and dimethylolbutanoic acid; Examples thereof include acids, polyhydroxy acids, aminosulfonic acids such as taurine and 2-hydroxyethanesulfonic acid, and hydroxysulfonic acids.

Examples of the corresponding salt-forming agent include monohydric and divalent metal hydroxides such as sodium hydroxide, potassium hydroxide and calcium hydroxide, and tertiary amine compounds such as ammonia, trimethylamine and triethylamine. No.

Examples of the compound having a quaternary or tertiary group which can be neutralized with an acid include N, N-dimethylethanolamine, N-methyldiethanolamine, N-methyl-N- (3- Amino alcohols and amines such as (aminopropyl) -ethanolamine and N, N-dimethylhydrazine.

Examples of the corresponding salt-forming agents include organic and inorganic acids such as hydrochloric acid, nitric acid, formic acid, acetic acid, methyl chloride and benzyl chloride, and compounds having a reactive halogen atom.

Examples of the compound containing a halogen atom or a corresponding strong acid ester which causes a quaternization reaction include 2-chloroethanol and 2-bromomethanol.

Examples of the corresponding salt-forming agent include tertiary amines, sulfides, phosphines and the like.

Ethylene oxide adduct: The monoalcohol used in the present invention as the monoalcohol or polyhydric alcohol in ethylene oxide alone or in the ethylene oxide and propylene oxide adducts is
Methanol, ethanol, propanol, butanol,
Examples of polyhydric alcohols such as pentanol, hexanol, heptanol, octanol, and lauryl alcohol include the above-mentioned polyhydric alcohols.

Surfactants for emulsification: anions and cations used for producing the aqueous polyurethane resin dispersion of the present invention;
As the nonionic surfactants, those usually used in the field of surfactants may be used alone or in combination.

That is, specifically, polyoxyethylene polyoxypropylene glycol, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, polyoxyethylene sorbitan fatty acid ester, sorbitan fatty acid ester, alkylol Nonionic surfactants such as amide type nonionic surfactants, sodium alkylbenzene sulfonate, sodium dialkyl sulfosuccinate, disodium polyoxyalkyl sulfosuccinate, ammonium or sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenol ether sulfate Ammonium or sodium, polyoxyethylene dialkyl allyl ether Sulfates of sodium, polyoxyethylene alkenyl allyl ether sulfate ammonium, higher alcohol sulfuric ester sodium salt, phosphate ester type anionic surfactant, an anionic surfactant such as castor oil sulfated oil is generally used.

In addition, cationic and amphoteric activators can be used.

Application Method When applying the composition of the present invention to an open pile coal mine, it is preferable to uniformly apply a spray amount of 0.01 kg or more of solids per unit area (m ² ). If the amount of spraying is small, the water repellent effect and the coal solidification strength are weakened, and the effect of preventing the rise of water and the effect of preventing coal flow are insufficient. Conversely, if the amount of spraying is too large, problems arise in terms of film drying properties, environmental aspects, and economic efficiency.

In order to improve the wettability between the composition and the coal and to apply the coating efficiently and efficiently, it is preferable to spray the coal mine with water before application.

The number of times of spraying is preferably two or more times in order to repair the coal mine surface portion that is not sufficiently covered by one spraying. Even in the case of two times, it is effective and efficient to reduce the amount of the first application and increase the amount of the second application.

As a method of uniformly coating the coal mine surface, it is particularly preferable to spray the mist.

[0051]

Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these Examples.

Synthesis Example 1 Polypropylene polyol (MW 400, 2.0 functional)
130 parts by weight, 1,4-butanediol (MW90,
2.0 functional) 10.7 parts by weight, castor oil-D (MW95
0, 2.7 functional) 23 parts by weight, dimethylolpropionic acid (MW 134, 2.0 functional) 11.7 parts by weight, tolylene diisocyanate (MW 174, 2.0 functional) 10
After synthesizing 5.4 parts by weight of an NCO group-containing urethane prepolymer in methyl ethyl ketone, mixing with 8.8 parts by weight of triethylamine, emulsifying in water, collecting methyl ethyl ketone, and preparing a polyurethane emulsion having a nonvolatile content of 30%. Obtained.

Synthesis Example 2 Polypropylene polyol (MW 400, 2.0 functional)
130 parts by weight, 1,4-butanediol (MW90,
2.0 functional) 10.7 parts by weight, castor oil-D (MW95
0, 2.7 functional) 23 parts by weight, dimethylolpropionic acid (MW 134, 2.0 functional) 11.7 parts by weight, tolylene diisocyanate (MW 174, 2.0 functional) 10
After synthesizing 5.4 parts by weight of an NCO group-containing urethane prepolymer in methyl ethyl ketone, mixing 8.8 parts by weight of triethylamine and 2.8 parts by weight of a nonionic surfactant, emulsifying in water, and emulsifying methyl ethyl ketone. This was collected to obtain a polyurethane emulsion having a nonvolatile content of 30%.

Synthesis Example 3 Polypropylene polyol (MW 400, 2.0 functional)
130 parts by weight, 1,4-butanediol (MW90,
9.3 parts by weight (2.0 functions), 16.1 parts by weight of polypropylene polyol (MW1000, 3.0 functions), dimethylolpropionic acid (MW134, 2.0 functions)
1 part by weight, tolylene diisocyanate (MW 174,
2.0 functional parts) An NCO group-containing urethane prepolymer consisting of 100 parts by weight was synthesized in methyl ethyl ketone, 8.4 parts by weight of triethylamine and 2.7 parts by weight of a nonionic surfactant were mixed, and emulsified in water. Then, methyl ethyl ketone was recovered to obtain a polyurethane emulsion having a nonvolatile content of 30%.

Synthesis Example 4 Polypropylene polyol (MW 400, 2.0 functional)
130 parts by weight, castor oil-D (MW 950, 2.7 functional) 23 parts by weight, dimethylolpropionic acid (MW13
4, 2.0 functional) 15 parts by weight, 4,4'-diphenylmethane diisocyanate (MW 250, 2.0 functional) 12
An NCO group-containing urethane prepolymer composed of 8 parts by weight was synthesized in methyl ethyl ketone, mixed with 11.3 parts by weight of triethylamine, and then emulsified in water to recover methyl ethyl ketone to obtain a polyurethane emulsion having a nonvolatile content of 30%. .

Synthesis Example 5 Polypropylene polyol (MW 400, 2.0 functional)
130 parts by weight, 1,4-butanediol (MW90,
2.0 parts) 27 parts by weight, castor oil-D (MW950,
NC consisting of 23 parts by weight of 2.7 functional groups and 122 parts by weight of tolylene diisocyanate (MW 174, 2.0 functional groups)
After synthesizing an O-group-containing urethane prepolymer in methyl ethyl ketone, 15 parts by weight of a nonionic surfactant was mixed with the mixture and emulsified in water to recover methyl ethyl ketone to obtain a polyurethane emulsion having a nonvolatile content of 30%.

Synthesis Example 6 Polypropylene polyol (MW 400, 2.0 functional)
130 parts by weight, 1,4-butanediol (MW90,
2.0 parts by weight, 10 parts by weight, castor oil-D (MW950,
(2.7 functional) 20 parts by weight, N-methyldiethanolamine (MW 119.2, 2.0 functional) 15 parts by weight, tolylene diisocyanate (MW 174, 2.0 functional) 110
After synthesizing an NCO group-containing urethane prepolymer consisting of parts by weight in methyl ethyl ketone, 2.9 parts by weight of formic acid was mixed with the mixture and emulsified in water to recover methyl ethyl ketone to obtain a polyurethane emulsion having a nonvolatile content of 30%.

Synthesis Example 7 Polybutylene adipate (MW2000, bifunctional) 70
Parts by weight, 1,6-hexanediol (MW118, bifunctional) 20 parts by weight, trimethylolpropane (MW13
NCO group-containing urethane polymer consisting of 3 parts by weight of 4, 2.0 functional), 6.5 parts by weight of dimethylolpropionic acid (MW 134, 2.0 functional), and 70 parts by weight of isophorone diisocyanate (MW 222, 2.0 functional) After synthesizing with methyl ethyl ketone, 4.9 parts by weight of triethylamine was mixed and emulsified in water to recover methyl ethyl ketone to obtain a polyurethane emulsion having a nonvolatile content of 30%.

Synthesis Example 8 Polypropylene polyol (MW 400, 2.0 functional)
130 parts by weight, 1,4-butanediol (MW90,
2.0 functional) 10.7 parts by weight, castor oil-D (MW95
0, 2.7 functional) 23 parts by weight, dimethylolpropionic acid (MW 134, 2.0 functional) 11.7 parts by weight, tolylene diisocyanate (MW 174, 2.0 functional) 10
After synthesizing an NCO group-containing urethane prepolymer consisting of 5.4 parts by weight in methyl ethyl ketone, 8.8 parts by weight of triethylamine, 2.8 parts by weight of a nonionic surfactant and 56 parts by weight of a wax containing paraffin / microcrystalline are mixed. After mixing, the mixture was emulsified in water, and methyl ethyl ketone was recovered to obtain a polyurethane emulsion having a nonvolatile content of 30%.

Synthesis Example 9 Polypropylene polyol (MW 400, 2.0 functional)
130 parts by weight, 1,4-butanediol (MW90,
2.0 functional) 10.7 parts by weight, castor oil-D (MW95
0, 2.7 functional) 23 parts by weight, dimethylolpropionic acid (MW 134, 2.0 functional) 11.7 parts by weight, tolylene diisocyanate (MW 174, 2.0 functional) 10
After synthesizing 5.4 parts by weight of an NCO group-containing urethane prepolymer in methyl ethyl ketone, 8.8 parts by weight of triethylamine, 2.8 parts by weight of a nonionic surfactant and 92 parts by weight of a paraffin / microcrystalline wax emulsion were added. After mixing, the mixture was emulsified in water, and methyl ethyl ketone was recovered to obtain a polyurethane emulsion having a nonvolatile content of 30%.

EXAMPLES AND COMPARATIVE EXAMPLES A water-dispersible resin emulsion and a wax emulsion were blended according to the compositions shown in Tables 1 and 2. In the comparative example, as shown in Table 2, only the water-dispersible resin was blended, and no water repellent was blended. Instead of the water-dispersible resin, only a nonionic surfactant was dispersed in water and used.

Tables 1 and 2 also show the application conditions of the coating composition in the coal solidification strength and coal moisture test described below.

[0063]

[Table 1]

[0064]

[Table 2]

Evaluation Test The compositions of Examples and Comparative Examples were evaluated according to the following test methods.

[Measurement of characteristic values] Tensile strength of the film when wet The following compounding solution was applied on a Teflon plate, and the temperature was 20 ° C and 60% R
After leaving the film in an atmosphere of H for 3 days to form a film of about 200 microns, the film was immersed in water at 20 ° C. for 1 day and then JIS K
The maximum tensile strength and elongation were measured according to the tensile strength test No. 6301 (punch type: No. 3 type).

Water repellency test (1) The following formulation was applied on a teffin plate,
The film was allowed to stand for 3 days in an atmosphere of 0% RH to form a film of about 200 microns, and then the contact angle with water was measured. (2) A stainless steel vat having a length of 25 cm, a width of 30 cm and a depth of 7 cm is smoothly filled with 4 kg of coal (particle size: 10 mm or less, internal moisture: 8%), and the following mixture is solid at 0.1 kg.
/ M ² , uniformly spread on the coal surface,
It was dried under an atmosphere of 60% RH for 3 days. After drying, the bat is inclined at an inclination angle of 40 degrees, and the rainfall is 13 mm on the coal surface.
Considerable forced watering was performed. The water repellency was evaluated by the water repellency ratio based on the following formula.

[0068]

The higher the water repellency ratio (%), the better the water repellency.

Coal solidification strength and coal moisture evaluation test Approximately 140 kg of coal (particle size 20 mm or less, coal moisture 8%)
Was used to produce a pyramid of pyramids of 1 m × 1 m square and about 50 cm high outside, and 3 kg / m ² of water was sprayed the day before spraying. The following day, the compositions of Examples 1 to 17 in Table 1 (no pre-watering only in Example 5) and the compositions of Comparative Examples 1 to 4 were applied to each coal mine in a predetermined amount and in a predetermined spraying method (one time of actual spraying). 3 kg
/ M ² ). The second spraying was performed 6 hours after the first spraying. Three days after spraying, the coal solidification strength and coal moisture (sampled at a depth of 10 cm from the coal surface) were measured. One week after spraying, the coal mine was subjected to forced watering equivalent to a rainfall of 50 mm, and two days later, the coal solidification strength and the coal moisture were measured.

It should be noted that the higher the coal solidification strength, the more difficult it is for coal to flow.

(1) Measurement of Coal Moisture Coal samples are dried in an oven at 107 ° C. for 2 hours, and the weight loss is measured.

[0073]

(2) Coal compaction strength The compressive strength of the coal surface was measured using a soil hardness meter (average value at 5 locations). The results are shown in Tables 3 and 4.

[0075]

[Table 3]

[0076]

[Table 4]

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C09D 201/00 C09D 201/00 (72) Inventor Takeshi Fujiwara Takenodai 2 F2-304, Nagaokakyo-shi, Kyoto (72) Inventor Yoshiyuki Kitada 5-7-13-403 Takabacho, Nada-ku, Kobe City, Hyogo Prefecture (72) Inventor Tatsuya Tanio 9-21-15 Asumigaoka, Midori-ku, Chiba City, Chiba F-term (reference) 4J002 AC011 AC071 AE032 BA011 BB002 BB061 BC021 BC051 BD031 BF021 BG001 BG121 CF011 CK021 CP002 FD202 GT00 HA07 4J038 BA212 CA011 CA021 CA041 CA061 CA071 CB002 CB051 CC021 CD021 CF021 CG001 CG171 DD001 DD121 DF002 DG001 MA08 MA10 NA07 PC04

Claims (8)

[Claims] 1. A water-dispersible resin and a water-repellent agent having a solid content ratio of 100
/ 1 to 100/50 uniformly dispersed in water,
A coating composition for protecting open pile coal. 2. The contact angle of the dried film of the composition with water is 7
2. The composition of claim 1 which is at least 0 °. 3. The wet film of the composition has a tensile strength of 10
The composition according to claim 1, wherein the composition is not less than kg / cm ² . 4. The composition according to claim 1, wherein the water-dispersible resin is a polyurethane emulsion. 5. The composition according to claim 1, wherein the water repellent is a natural or synthetic wax. 6. A continuous film is formed by applying the composition according to any one of claims 1 to 5 in an amount of 0.01 kg / m ² or more in terms of solid content to an exposed surface of a field pile of coal. A method for protecting unloaded coal. 7. The method of claim 6, wherein the composition is applied after the exposed surface of the open pile is wetted with water. 8. The method according to claim 6, wherein the application of the composition is repeated at least twice.