JP3170390B2 - Ballast coating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ballast coating method which is effective in preventing ballast from scattering when a vehicle passes and preventing ballast from flowing out due to wind and rain.

[0002]

2. Description of the Related Art Ballasts such as crushed stones and gravel laid on a track bed of a track move by wind pressure generated when a vehicle passes, and are scattered in severe cases. Each year, this trend is exacerbated by the speeding up of vehicles, which can affect private houses and buildings near the track and damage the underfloor part of the vehicle. In addition, the movement and outflow of the small-diameter ballast can also occur during a strong wind or heavy rain. The suppression of ballast movement
Although it is mainly due to the internal weight of the individual ballast due to its own weight and the ridge angle, when ballast having a small diameter, light weight and poor ridge angle is simply deposited, a single ballast on the surface cannot withstand a large wind pressure. As a countermeasure against this, it is effective to connect a large number of ballasts with an adhesive. Conventionally, a synthetic resin emulsion, such as a vinyl acetate emulsion, which forms a film by drying at room temperature and exhibits an adhesive force has been sprayed. However, future sprays will spill if diluted with rainwater before drying, causing pollution. In addition, there is a problem that the coating swells, peels off, disappears due to repeated rainfall even after drying, and loses its effect.

[0003]

In view of the above situation, the present invention adheres well to wet ballasts and does not fall off or flow out even after rainfall, so that spraying can be performed in any weather conditions. The purpose of the present invention is to provide a ballast coating method which is possible and is effective for preventing ballast from scattering and flowing out.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that a specific synthetic resin emulsion having good adhesion to a wet surface composed of a specific range of monomers and a specific synthetic resin emulsion have been developed. We found that there is a possibility of solving the problem by simultaneously spraying separately the electrolyte solution for gelling the emulsion as it adheres to the ballast, and further tested the type and amount of the monomer and the electrolyte solution, and Reached.

[0005] That is, the present invention has solved the above-mentioned problems, and comprises: (a) an ester of acrylic acid or methacrylic acid ; a diester of maleic acid, fumaric acid or itaconic acid ; vinyl esters of; one or more 70 to 99 wt% of (b) one or more 0.5 to 15 wt% of an unsaturated monomer having a carboxyl group, (iii) a sulfonic acid group or a sulfonic 0.5 to 15% by weight of one or more unsaturated monomers having an acid-base, (d) one or more ethylenically unsaturated monomers other than (a), (b) and (c) above; Is a mixture of a part A composed of a synthetic resin emulsion obtained by emulsion copolymerization of a monomer mixture composed of two or more kinds of the balance [a total of (a) to (d) 100%] and a part B composed of an electrolyte solution. Spray with a spray gun, Ballast coating method characterized by forming a gel coating which covers the surface, the one in which the subject matter.

Hereinafter, the present invention will be described in detail. The synthetic resin emulsion of Part A used in the present invention can be easily sprayed by a general spraying machine and a sprayer, and has a good affinity for a wet surface, so that it affects the weather on rainy and sunny days. Work can be performed without being performed, and also has good reactivity with the electrolyte solution of Part B and immediately forms a gelled film,
Helps prevent ballast from scattering and outflow.

The component (A) is a main component of the synthetic resin emulsion polymer and imparts dry film forming properties, film strength and water resistance of the film. If the amount is less than 70% by weight, these effects are insufficient. This component (a) includes acrylic acid and methacrylic acid methyl, ethyl, propyl,
i-propyl, n-butyl, i-butyl, t-butyl,
Esters such as hexyl, cyclohexyl, 2-ethylhexyl, lauryl, stearyl, oleyl, ethoxyethyl or benzyl, maleic acid, diesters of unsaturated dicarboxylic acids such as fumaric acid and itaconic acid with the above ester-forming components, and acetic acid And vinyl esters of fatty acids such as propionic acid, lauric acid, stearic acid and versatic acid.

[0008] The unsaturated monomer having a carboxyl group as component (ii) imparts mechanical stability to the synthetic resin emulsion, improves workability with a spray gun, and improves adhesion to ballast. . If the amount is less than 0.5% by weight, these effects are insufficient, and if it exceeds 15% by weight, the water resistance of the coating deteriorates. Examples of the monomer include unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid, unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid, and unsaturated dicarboxylic acids such as monomethyl maleate and monobutyl itaconate. Monoesters of acids and alcohols are exemplified.

The unsaturated monomer having a sulfonic acid group or a sulfonic acid group as the component (c) imparts wet adhesion in which the synthetic resin emulsion adheres well to ballast wet with rainwater, If the amount is less than 0.5% by weight, this effect is poor, and if it exceeds 15% by weight, the water resistance of the coating is impaired. Examples of the monomer include vinyl sulfonic acid, styrene sulfonic acid, allyl sulfonic acid, 3-allyloxy-2-hydroxypropane sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, and allyl alkyl sulfosuccinate. The sodium sulfonic acid in the molecule in these compounds,
Salts such as potassium or ammonium are also included.

The component (d) comprises (a), (b) and (c)
It is an ethylenically unsaturated monomer other than the component, and is used for imparting physical properties and film properties that cannot be exhibited only by the above components (a), (b), and (c), but impairs the object of the present invention. To avoid this, usually 30% by weight or less of the total amount of the monomers is used. Examples of such monomers include styrene, styrene derivatives, vinyl chloride, vinylidene chloride, acrylonitrile, glycidyl (meth) acrylate, divinylbenzene, ethylene glycol dimethacrylate, and the like.

The emulsion copolymerization method may be a general method, and various anionic and nonionic surfactants are used as an emulsifier, and potassium persulfate is used as a polymerization initiator.
A redox catalyst using ammonium persulfate, hydrogen peroxide, or a combination of these peroxides and a reducing agent is used. The emulsion polymerization system may contain, if necessary, a polymerization aid usually used for emulsion polymerization, such as a chain transfer agent, a buffer, and inorganic salts. The emulsion copolymerized synthetic resin emulsion thus obtained has a solid content, that is, T
g (glass transition temperature) is desirably -10 ° C to -60 ° C.
If the ratio is out of the range, the objective may not be achieved due to insufficient film-forming properties at low temperatures and a decrease in film strength at high temperatures.

The electrolyte solution of Part B is added for gelling, coagulating, salting out and further crosslinking the resin emulsion of Part A, and is preferably a monovalent, divalent or trivalent metal inorganic acid salt aqueous solution. , Na, K, Mg, Ca, Zn, Fe,
Al hydrochloric acid, nitric acid, sulfuric acid, borate and the like are used. These include sodium chloride, potassium chloride, magnesium chloride, calcium chloride, zinc chloride, aluminum chloride, ferrous chloride, ferric chloride, sodium sulfate, aluminum sulfate, or a complex salt thereof, or an aqueous solution of sodium borate. Illustrated, one or two of these
More than one species can be used in combination.

[0013] Since the resin emulsion gels rapidly due to the electrolyte solution in part B and loses fluidity, the gelled emulsion is not easily diluted and flows out even by rainfall during or after spraying and before drying. Absent. Further, since the polymer particles in the emulsion are no longer dispersed into single particles, they do not become turbid even when washed with rain, and do not cause wastewater pollution. The metal ions in the electrolyte are more than 2
Trivalent, more trivalent, the greater the emulsion coagulation effect,
Further, the polyvalent metal ion reacts with a carboxyl group in the polymer to form a metal salt crosslink, so that the water resistance of the dried film is remarkably improved. Accordingly, the electrolyte is more preferably a salt of a divalent or trivalent metal, that is, a salt of Mg, Ca, Zn, Fe, or Al.

The coating method of the present invention may be performed by an appropriate device such as an air spray, an airless spray, or a simple general sprayer such as a backpack type, depending on the application place, scale, etc., and there is no particular limitation on the spraying means. . However, since it is desirable that the synthetic resin emulsion of Part A and the electrolyte solution of Part B are separately sprayed to the same place and that the emulsion gels instantaneously, a sprayer or sprayer with two nozzles is used. It is desirable to spray or spray at the same time.

[0015]

EXAMPLES The present invention will be specifically described based on examples and comparative examples, but the present invention is not limited to the examples. In the examples, parts and% are parts by weight and% by weight, respectively.
Is shown. Example 1 A synthetic resin emulsion was prepared as follows. Synthetic resin emulsion (1): In a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube 70 parts of 2-ethylhexyl acrylate 20 parts of vinyl acetate 9 parts of methacrylic acid 9 parts 2-acrylamide-2-methyl Sodium propanesulfonate 1 part Polyethylene glycol nonyl phenyl ether (HLB17) 2 parts Sodium lauryl sulfate 0.5 part Ammonium persulfate 0.2 part Water 100 parts were charged and subjected to an emulsion copolymerization reaction at 70 ° C. for 6 hours while stirring in a nitrogen stream.

Then, the mixture is cooled and adjusted to pH 6 to 7 with aqueous ammonia.
To obtain a stable synthetic resin emulsion without coarse particles. It has a solids content of 50%, pH
6.2, viscosity 200 centipoise (25 ° C, Brookfield viscometer), Tg value -43 ° C. Solution A was prepared by mixing 100 parts of this synthetic resin emulsion with 1 part of red pigment and 20 parts of water to make it easier to judge the test. Electrolyte (1) was prepared by dissolving 10 parts of calcium chloride in 30 parts of water. Of B
The liquid was adjusted. The following tests 1 to 3 were performed using the solution A and the solution B. The results were as shown in Table 1.

1. Adhesiveness Andesite slabs (30 cm in width, 30 cm in length, 9.5 cm in thickness, and rough polished products) specified in JISA5003 (stone) were used as the adherend for the spray test. This is fixed at an angle of 45 degrees from the horizontal,
Put solution A and solution B in separate containers at the ratio adjusted above,
500g / total through air spray gun with mouth nozzle
It was sprayed an amount of the m ^2. The emulsion gelled as soon as it adhered to the slab, lost its fluidity, and the liquid falling from the slab was very small. This was left at 25 ° C. for one day to form a dried polymer film on the surface of the stone slab. A cellophane tape was stuck and peeled off from this film, but the film did not peel off because of good adhesion to the stone slab.

2. Adhesion to Wet Surface Another stone of the same type and size was fixed at a 45 ° angle, and the wet surface immediately after sprinkling and spraying was subjected to the same spraying and cellophane test as described above. The results were the same as above, and the adhesion to the slab was good and the coating did not peel off.

3. Adhesion condition after water spraying The dry adhesion film on the stone slab surface prepared for test 1 was sprayed for 1 hour or 3 hours using another spray gun under the condition of about 0.2 L / min.m ² . The state was visually observed with the degree of the red pigment and evaluated on a three-point scale. 〇: No change, △: About 1/3 dropout, with outflow, ×: Almost dropout, outflow

Examples 2 to 5 Synthetic resin emulsions (2) to (4) having the following compositions and properties and an electrolyte solution (2) were obtained in the same manner as in the synthetic resin emulsion (1). Synthetic resin emulsion (2): (Composition charged with monomer) 2-ethylhexyl acrylate 78 parts Methyl methacrylate 10 parts Methacrylic acid 2 parts Glycidyl acrylate 5 parts Sodium styrenesulfonate 5 parts (properties) Solid content = 52% pH = 6.8, viscosity 100 centipoise (25 ° C), Tg = -56 ° C

Synthetic resin emulsion (3): (Composition of monomers) 64 parts of butyl acrylate 32 parts of methyl methacrylate 3 parts of methacrylic acid 3 parts of sodium 2-acrylamido-2-methylpropanesulfonate 1 part (properties) Solid content = 50%, pH = 6.2, viscosity = 350 centipoise (25 ° C.), Tg = −13 ° C.

Synthetic resin emulsion (4): (Composition of charged monomers) 2-ethylhexyl acrylate 70 parts Vinyl acetate 16 parts Acrylic acid 7 parts Sodium vinyl sulfonate 7 parts (properties) Solid content = 48%, pH = 6.3, viscosity = 30 centipoise (25 ° C.), Tg = −49 ° C.

Electrolyte solution (2) 20 parts of sodium sulfate, 60 parts of water

Next, in the same manner as in Example 1, each of the above synthetic resin emulsions (2) to (4)
Liquid A was prepared by mixing 100 parts, 1 part of red pigment and 20 parts of water. These were combined with the electrolyte solution B in the combination shown in Table 1 and sprayed in the same manner as in Example 1 to observe the adhesion state after scotch tape test and water spraying.
The result as shown in was obtained.

[0025]

[Table 1]

Comparative Example 1 The same test as in the example was performed by spraying under the following conditions. 1. Adhesion In Example 1, instead of the synthetic resin emulsion (1), 100 parts of a vinyl acetate resin emulsion [manufactured by Konishi Co., Ltd., Bond CH-18], 100 parts of a red pigment, and 20 parts of water were mixed to prepare the liquid A. 375 g / m ^{2 was} sprayed without using the electrolyte solution B.
The emulsion dropped significantly from the slab during and after spraying, leaving only about 140 g / m ² on the surface of the slab, and there was a large difference in the residual adhesion between the upper and lower slabs.

2. Adhesion to wet surface As a result, the emulsion dropped much more than the above, and the amount remaining on the slab surface was only about 90 g / m ² .

3. Adhesion state after watering The amount of residual adhesion 1 hour after watering was extremely small, and after 3 hours watering, most of the particles fell off and flowed out.

[0029]

According to the present invention, spraying can be performed in any weather conditions, adheres well to a wet surface, and prevents scattering.
A ballast coating method is provided that is effective in preventing spills.
Due to this property, the ballast coating method of the present invention is extremely advantageous in practical use.

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Claims (1)

(57) [Claims] To 1. A track track bed ballast surface, (b) esters of acrylic acid or methacrylic acid; maleic acid, diesters of fumaric acid or itaconic acid; 70 to 99 wt one or more, vinyl esters of fatty acids (B) one or more unsaturated monomers having a carboxyl group 0.5 to 15% by weight; (c) one or two unsaturated monomers having a sulfonic acid group or a sulfonate group (D) a monomer mixture consisting of one or more of the ethylenically unsaturated monomers other than the above (a), (b) and (c), and the balance [(a) A) consisting of a synthetic resin emulsion obtained by emulsifying and copolymerizing (d) a part A consisting of a synthetic resin emulsion, and a part B consisting of an electrolyte solution, are sprayed with a spray gun to form a gelled film covering the surface. A bar characterized by being formed Last coating method.