Asphalt emulsion decomposer and its use

Abstract

To provide a decomposing agent for a cationic asphalt emulsion excellent in decomposability even in construction at a low temperature such as in winter or at night.SOLUTION: A decomposing agent for a cationic asphalt emulsion comprises a sulfur-containing anionic surfactant (A), at least one sulfur-containing inorganic salt (B) selected from sulfate, sulfite, bisulfite and thiosulfate, and a compound (C) represented by a specific general formula (1), and has a specific gravity of 1.03 - 1.30 at 20°C. It is preferable that the surfactant (A) is a mixture of two or more kinds and essentially contains an aromatic sulfonate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an asphalt emulsion decomposer and its use. [Background technology]

[0002] Asphalt is the final refined product obtained after petroleum distillation to extract naphtha, gasoline, kerosene, diesel, etc., and has long been used as a paving material. Asphalt is a highly viscous semi-solid or solid at room temperature, and its high adhesiveness makes it very difficult to handle. One known method for improving workability during handling at room temperature is to use asphalt in a form emulsified in water using an emulsifier, and this emulsion is called asphalt emulsion. One way to classify asphalt emulsions is by the emulsifier used, which can be cationic, anionic, nonionic, etc., and the majority of asphalt emulsions used for road paving are cationic asphalt emulsions.

[0003] Required properties of asphalt emulsion include storage stability from the time of its production until its use at the construction site, and mechanical stability to prevent the emulsion from breaking down even when subjected to external forces such as shear and compression caused by pumps used to transport and spray the emulsion. Furthermore, after the asphalt emulsion is sprayed at the construction site, it is highly desirable that it be decomposed as quickly as possible and separated into water and asphalt as quickly as possible. This is because if moisture remains in the asphalt, it will not have the inherent adhesiveness that asphalt should have, resulting in poor adhesion. Generally, after spraying asphalt emulsion, it is necessary to wait until the moisture in the agent has evaporated and fully decomposed, during which time traffic restrictions are required on the road, resulting in a long time before the road can be reopened to traffic.

[0004] To solve this problem, a method using a decomposer that breaks down the emulsion of asphalt emulsion is known, and specific decomposers for cationic asphalt emulsions are proposed in Patent Documents 1 and 2. However, sufficient decomposition ability of asphalt emulsions could not be obtained. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-122352 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-164345 Summary of the Invention [Problem to be solved by the invention]

[0006] As a result of investigating the cause of the above-mentioned insufficient decomposition ability, it was found that the decomposing agents for conventional cationic asphalt emulsions are temperature dependent, and sufficient decomposition ability cannot be obtained, particularly at low temperatures. Therefore, an object of the present invention is to provide a decomposer for cationic asphalt emulsions that has excellent decomposability even when applied at low temperatures such as in winter or at night. [Means for solving the problem]

[0007] As a result of extensive research, the present inventors have discovered that the above-mentioned problems can be solved by a decomposer for cationic asphalt emulsions that contains a specific anionic surfactant, a specific sulfur-containing inorganic salt, and a compound having a specific structure and exhibits a certain specific gravity, and have thus arrived at the present invention. That is, the decomposer for the cationic asphalt emulsion of the present invention contains a sulfur-containing anionic surfactant (A), at least one sulfur-containing inorganic salt (B) selected from sulfates, sulfites, hydrogen sulfites, and thiosulfates, and a compound (C) represented by the following general formula (1), and has a specific gravity at 20°C of 1.03 to 1.30. RO-[(PO)p / (EO)q]-H (1)

[0008] (In formula (1), R represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, a phenyl group, an alkylphenyl group having 7 to 15 carbon atoms, an alkoxyphenyl group having 7 to 15 carbon atoms, or a benzyl group. PO represents an oxypropylene group, and EO represents an oxyethylene group. p and q represent the average number of moles added, where p=1 to 40, q=0 to 39, and p+q=1 to 40. [(PO)p / (EO)q] is a polyoxyalkylene group formed by the addition of p moles of PO to q moles of EO. The addition of PO and EO may be either a random addition or a block addition.) (However, when R is a hydrogen atom, p=2 to 40, q=0 to 39, and p+q=2 to 40.)

[0009] The decomposer for the cationic asphalt emulsion preferably satisfies the following invention-specific requirements. 1) The surfactant (A) is a mixture of two or more types and essentially contains an aromatic sulfonate. 2) The compound (C) has an average molecular weight (Mw) of 1,000 or less. 3) The solubility of the compound (C) in 100 g of water at 20° C. is 20 g or less. 4) It further contains a carboxylate (D) having 6 or more carbon atoms. 5) With respect to the decomposition agent, the weight ratio of the surfactant (A) is 0.1 to 40% by weight, the weight ratio of the sulfur-containing inorganic salt (B) is 0.1 to 20% by weight, and the total weight ratio (C+D) of the compound (C) and the carboxylate (D) is 0.1 to 40% by weight.

[0010] The method for spraying the asphalt emulsion of the present invention is a method for spraying the cationic asphalt emulsion by bringing the decomposing agent into contact with the cationic asphalt emulsion. [Effects of the Invention]

[0011] The decomposer for the cationic asphalt emulsion of the present invention has the effect of excellent decomposability at low temperatures. The method for spraying the asphalt emulsion of the present invention has the effect of excellent decomposability at low temperatures. DETAILED DESCRIPTION OF THE INVENTION

[0012] The decomposer for cationic asphalt emulsion of the present invention contains a sulfur-containing anionic surfactant (A), at least one sulfur-containing inorganic salt (B) selected from sulfates, sulfites, hydrogen sulfites, and thiosulfates, and a compound (C) represented by the following general formula (1), and exhibits a specific specific gravity at 20°C. RO-[(PO)p / (EO)q]-H (1) (In formula (1), R represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, a phenyl group, an alkylphenyl group having 7 to 15 carbon atoms, an alkoxyphenyl group having 7 to 15 carbon atoms, or a benzyl group. PO represents an oxypropylene group, and EO represents an oxyethylene group. p and q represent the average number of moles added, where p=1 to 40, q=0 to 39, and p+q=1 to 40. [(PO)p / (EO)q] is a polyoxyalkylene group formed by the addition of p moles of PO to q moles of EO. The addition of PO and EO may be either a random addition or a block addition.) (However, when R is a hydrogen atom, p=2 to 40, q=0 to 39, and p+q=2 to 40.)

[0013] [Sulfur-containing anionic surfactant (A)] The sulfur-containing anionic surfactant (A) is an essential component of the cationic asphalt emulsion decomposer of the present invention, and neutralizes the charge of the cationic emulsifier present on the oil droplet surfaces of the asphalt emulsion. Furthermore, because the hydrophobic group portion has affinity with the asphalt emulsion, it breaks down the oil droplets and promotes their coalescence. The surfactant (A) can be used in combination with the sulfur-containing inorganic salt (B) and compound (C), which will be described later, to achieve excellent low-temperature decomposability.

[0014] Examples of the surfactant (A) include aromatic sulfonates, aromatic sulfonic acids, aliphatic sulfonic acids, aliphatic sulfonates, and organic sulfates. Examples of aromatic sulfonates or aromatic sulfonic acids include alkylbenzenesulfonic acids, alkylbenzenesulfonates, naphthalenesulfonic acids, naphthalenesulfonates, alkylnaphthalenesulfonates, naphthalenesulfonate-formalin condensates, naphthalenesulfonate-formalin condensate salts, xylenesulfonates, toluenesulfonates, cumenesulfonates, and alkoxybenzenesulfonates. Examples of the aliphatic sulfonic acids or aliphatic sulfonate salts include alkyl or alkenyl sulfonic acids, alkyl or alkenyl sulfonate salts, melamine sulfonic acid, melamine sulfonate salts, alkyl melamine sulfonic acids, alkyl melamine sulfonate salts, melamine sulfonate-formaldehyde condensates, melamine sulfonate-formaldehyde condensates, alkyl melamine sulfonate-formaldehyde condensates, alkyl melamine sulfonate-formaldehyde condensates, alkyl sulfosuccinates, alkyl sulfosuccinate salts, fatty acid amide sulfonic acids, and fatty acid amide sulfonate salts.

[0015] Examples of organic sulfates include alkyl sulfates, alkyl sulfate salts, polyoxyalkylene alkyl ether sulfates, polyoxyalkylene alkyl ether sulfates, isobutyl oleate sulfate, alkylphenyl sulfates, alkylphenyl sulfates, polyoxyalkylene alkylphenyl ether sulfates, polyoxyalkylene alkylphenyl ether sulfates, sulfates of fats and oils, salts of sulfates of fats and oils, sulfates of hydrogenated fats and oils, salts of sulfates of hydrogenated fats and oils, sulfates of unsaturated fatty acid esters, and salts of sulfates of unsaturated fatty acid esters.

[0016] Among the sulfur-containing anionic surfactants (A), it is preferable to essentially contain an aromatic sulfonate salt in order to achieve the effects of the present invention. Among the sulfur-containing anionic surfactants (A), from the viewpoint of exerting the effects of the present application, alkyl sulfates, polyoxyalkylene alkyl ether sulfates, salts of sulfates of fats and oils, salts of sulfates of unsaturated fatty acid esters, alkyl sulfosuccinates, alkyl or alkenyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, xylene sulfonates, and alkoxy benzene sulfonates are preferred, and mixtures of two or more of these are even more preferred from the viewpoint of improving the decomposition property of the asphalt emulsion at low temperatures.

[0017] The alkyl group of the alkyl sulfate preferably has 4 to 30 carbon atoms, more preferably 6 to 22 carbon atoms, and even more preferably 8 to 18 carbon atoms, from the viewpoint of improving the decomposition property of the asphalt emulsion at low temperatures. The alkyl group of the polyoxyalkylene alkyl ether sulfate preferably has 4 to 30 carbon atoms, more preferably 6 to 22 carbon atoms, and even more preferably 8 to 18 carbon atoms, from the viewpoint of improving the decomposition property of the asphalt emulsion at low temperatures. Examples of the polyoxyalkylene group of the polyoxyalkylene alkyl ether sulfate include a polyoxyethylene group, a polyoxypropylene group, a polyoxybutylene group, and a group obtained by polymerizing two or more selected from the monomers constituting these groups. The number of moles of the polyoxyalkylene group added is preferably 1 to 30.

[0018] From the viewpoint of improving the decomposition property of the asphalt emulsion at low temperatures, the alkyl group of the alkylsulfonic acid preferably has 4 to 30 carbon atoms, more preferably 6 to 22, and even more preferably 8 to 18. The alkyl group of the alkylsulfonic acid may be linear or branched, and the alkyl group may have a distribution. The alkylsulfonic acid is not particularly limited, but examples thereof include pentanesulfonic acid, hexanesulfonic acid, heptanesulfonic acid, octanesulfonic acid, decanesulfonic acid, dodecanesulfonic acid, tetradecanesulfonic acid, hexadecanesulfonic acid, octadecanesulfonic acid, icosanesulfonic acid, and heneicosanesulfonic acid.

[0019] The salt of the organic sulfonic acid is not particularly limited, but examples thereof include sodium salts, potassium salts, magnesium salts, calcium salts, aluminum salts, monoethanolamine salts, diethanolamine salts, triethanolamine salts, and ammonium salts. Among these, sodium salts, potassium salts, and ammonium salts are preferred in terms of availability, safety, and environmental impact.

[0020] Examples of alkylbenzenesulfonic acids include octylbenzenesulfonic acid, decylbenzenesulfonic acid, dodecylbenzenesulfonic acid, xylenesulfonic acid, toluenesulfonic acid, and cumenesulfonic acid.

[0021] Examples of alkyl sulfosuccinic acids include dioctyl sulfosuccinic acid, didecyl sulfosuccinic acid, didodecyl sulfosuccinic acid, ditridecyl sulfosuccinic acid, octyl sulfosuccinic acid, decyl sulfosuccinic acid, dodecyl sulfosuccinic acid, and tridecyl sulfosuccinic acid.

[0022] [Sulfur-containing inorganic salt (B)] The sulfur-containing inorganic salt (B) is an essential component of the decomposer for the cationic asphalt emulsion of the present invention, and the sulfate ions, sulfite ions, hydrogen sulfite ions, and thiosulfate ions contribute to neutralizing the electric charge of the cationic emulsifier present on the surface of the oil droplets in the asphalt emulsion. In addition, the specific gravity of the decomposer can be adjusted to a specific range, and the difference in specific gravity with the asphalt emulsion sprayed earlier promotes natural mixing, resulting in the effect of rapid decomposition progressing not only in the surface layer that came into contact when sprayed, but also in the lower layer that did not come into contact with the decomposer.

[0023] Examples of the sulfur-containing inorganic salt (B) include sodium sulfate, potassium sulfate, magnesium sulfate, calcium sulfate, aluminum sulfate, iron sulfate, cobalt sulfate, nickel sulfate, copper sulfate, zinc sulfate, silver sulfate, zirconyl sulfate, ammonium sulfate, ammonium iron sulfate, aluminum ammonium sulfate, aluminum potassium sulfate, sodium nitrite, sodium hydrogen nitrite, and sodium thiosulfate. Among these, sodium sulfate, potassium sulfate, ammonium sulfate, and sodium thiosulfate are preferred in terms of availability, safety, and environmental impact.

[0024] [Compound (C)] The compound (C) is represented by the above general formula (1). In formula (1), R represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, a phenyl group, an alkylphenyl group having 7 to 15 carbon atoms, an alkoxyphenyl group having 7 to 15 carbon atoms, or a benzyl group. PO represents an oxypropylene group, and EO represents an oxyethylene group. In the case of an alkyl group having 1 to 8 carbon atoms, the alkyl group preferably has 1 to 6 carbon atoms, and more preferably has 1 to 4 carbon atoms. p and q each represent the average number of moles added, where p=1 to 40, q=0 to 39, and p+q=1 to 40. In terms of achieving the effects of the present invention, p is preferably 1 to 30, more preferably 1 to 20, even more preferably 1 to 15, and particularly preferably 1 to 12. From the viewpoint of achieving the effects of the present invention, q is preferably an integer of 0 to 30, more preferably an integer of 0 to 20, even more preferably an integer of 0 to 10, and particularly preferably an integer of 0 to 8. From the viewpoint of achieving the effects of the present invention, p+q is preferably 1 to 30, more preferably 1 to 20, even more preferably 1 to 10, and particularly preferably 1 to 8.

[0025] [(PO)p / (EO)q] indicates the addition form of PO and EO, and may be either a random addition form or a block addition form. When R is a hydrogen atom, p=2 to 40, q=0 to 39, and p+q=2 to 40. From the viewpoint of achieving the effects of the present invention, the average molecular weight (Mw) of the compound (C) is preferably 1,000 or less, more preferably 800 or less, and even more preferably 600 or less. The preferred lower limit of the average molecular weight (Mw) of the compound (C) is 90. From the viewpoint of achieving the effects of the present invention, it is preferable that p>q.

[0026] From the viewpoint of achieving the effects of the present invention, the solubility of the compound (C) in 100 g of water at 20° C. is preferably 20 g or less, more preferably 15 g or less, and even more preferably 10 g or less. The lower limit of the solubility of the compound (C) in 100 g of water at 20° C. is 0.

[0027] Examples of the compound (C) include polyoxyalkylene methyl ether, polyoxyalkylene ethyl ether, polyoxyalkylene propyl ether, polyoxyalkylene butyl ether, polyoxyalkylene hexyl ether, polyoxyalkylene octyl ether, polyoxyalkylene phenyl ether, polyoxyalkylene alkylphenyl ether, polyoxyalkylene benzyl ether, dipropylene glycol, and polyoxyalkylene glycol.

[0028] [Carboxylic acid salts with 6 or more carbon atoms (D)] The decomposer for the cationic asphalt emulsion of the present invention preferably further contains a carboxylate (D) having 6 or more carbon atoms, from the viewpoint of improving the decomposability of the asphalt emulsion at low temperatures. Examples of the carboxylic acid salt (D) having 6 or more carbon atoms include alkali metal salts of monobasic acids, alkali metal salts of polycarboxylic acids, and alkali metal salts of aromatic carboxylic acids.

[0029] The fatty acid used as the raw material for the alkali metal salt of a monobasic acid may have a distribution in the number of carbon atoms in the alkyl group, and the alkyl group may be linear or branched, and may be saturated or unsaturated. The number of carbon atoms in the alkyl group is preferably 6 to 24, more preferably 8 to 22, still more preferably 8 to 20, and particularly preferably 8 to 18. Examples of the alkali metal salt of a monobasic acid include sodium caprate, sodium oleate, sodium laurate, sodium coconut fatty acid, sodium tallow fatty acid, sodium castor oil fatty acid, and sodium naphthenate. Examples of alkali metal salts of polycarboxylic acids include disodium adipate, disodium pimelate, disodium suberate, disodium sebacate, disodium undecanoate, disodium dodecanoate, trisodium citrate, sodium carboxymethylcellulose, and sodium polymethacrylate. Examples of alkali metal salts of aromatic carboxylic acids include sodium benzoate, sodium phthalate, sodium terephthalate, sodium hydroxybenzoate, sodium salicylate, sodium anisate, and sodium cinnamate.

[0030] [Cationic asphalt emulsion decomposer] The specific gravity of the decomposer of the cationic asphalt emulsion of the present invention at 20°C is 1.03 to 1.30, preferably 1.03 to 1.20, and more preferably 1.03 to 1.15. If it is less than 1.03, decomposition does not progress to the non-contact lower layer portion. On the other hand, if it exceeds 1.30, the decomposition ability of the asphalt emulsion at low temperatures is poor.

[0031] The viscosity at 20°C of the decomposer for the cationic asphalt emulsion of the present invention is preferably 500 mPa·S or less, more preferably 400 mPa·S or less, even more preferably 300 mPa·S or less, and particularly preferably 200 mPa·S or less, from the viewpoint of excellent decomposability of the asphalt emulsion at low temperatures and uniform dispersion over a wide area. From the viewpoint of excellent decomposability of the asphalt emulsion at low temperatures, the preferred lower limit is 0.1 mPa·S.

[0032] From the viewpoint of excellent instantaneous decomposition properties, the weight proportion of the sulfur-containing anionic surfactant in the decomposing agent of the cationic asphalt emulsion of the present invention is preferably 0.1 to 40.0% by weight, more preferably 1.0 to 30.0% by weight, even more preferably 5.0 to 25.0% by weight, and particularly preferably 8.0 to 25.0% by weight. The weight ratio of the sulfur-containing inorganic salt in the decomposing agent of the cationic asphalt emulsion of the present invention is preferably 0.1 to 20.0% by weight, more preferably 0.5 to 15.0% by weight, and even more preferably 1.0 to 10.0% by weight. If it is less than 0.1% by weight, decomposition may not progress to the non-contact lower layer portion. If it exceeds 20.0% by weight, the stability of the decomposing agent solution may decrease, making uniform spraying difficult. The total weight ratio (C+D) of the compound (C) and the carboxylate (D) in the decomposing agent of the cationic asphalt emulsion of the present invention is preferably 0.1 to 40.0 wt%, more preferably 1.0 to 35.0 wt%, even more preferably 3.0 to 30.0 wt%, and particularly preferably 5.0 to 25.0 wt%. If it is less than 0.1 wt%, decomposition may not progress to the non-contact lower layer portion. If it exceeds 40.0 wt%, the stability of the decomposing agent solution may decrease, making uniform spraying difficult.

[0033] The pH of the decomposer for the cationic asphalt emulsion of the present invention is preferably 5.0 to 8.0, more preferably 5.5 to 7.5, in view of the decomposability of the asphalt emulsion at low temperatures, safety during spraying, and environmental impact.

[0034] The decomposer for cationic asphalt emulsion of the present invention is preferably used with the cationic asphalt emulsion "PK-4" specified in JIS-K2208 or "PKM-T" and "PKM-TQ" specified in the Japan Asphalt Emulsion Association Standard JEAAS, because the effects of the present application are exhibited without being affected by the type of emulsifier or other ingredients.

[0035] The decomposer for the cationic asphalt emulsion of the present invention may contain other components such as a water-soluble solvent, an emulsifier / solubilizer, and an antifoaming agent to the extent that the effect of the decomposer is not impaired.

[0036] The water-soluble solvent is not particularly limited, but examples thereof include methanol, ethanol, propanol, butanol, ethylene glycol, diethylene glycol, 2-ethoxyethanol, 2-(2-ethoxyethoxy)ethanol, 2-butoxyethanol, 2-(2-butoxyethoxy)ethanol, 3-methoxy-3-methyl-1-butanol, phenoxyethanol, dimethylformamide, dimethyl sulfoxide, and the like, and one or more of these may be used in combination.

[0037] The emulsifier / solubilizer is not particularly limited, and examples thereof include anionic surfactants other than the sulfur-containing anionic surfactant (A) and the carboxylic acid salt (D) having 6 or more carbon atoms of the present invention, cationic surfactants, amphoteric surfactants, nonionic surfactants, etc., and one or more of these may be used in combination.

[0038] The defoaming agent is not particularly limited, but examples thereof include ester-based defoaming agents, polyether-based defoaming agents, mineral oil-based defoaming agents, silicone-based defoaming agents, powder defoaming agents, and the like, and one or more of these may be used in combination.

[0039] The weight proportion of other components in the cationic asphalt emulsion decomposer of the present invention is not particularly limited, but is preferably 0.001 to 50 wt%, more preferably 0.01 to 30 wt%, even more preferably 0.01 to 20 wt%, and particularly preferably 0.01 to 10 wt% of the cationic asphalt emulsion decomposer. If the weight proportion of other components is less than 0.001 wt% of the cationic asphalt emulsion decomposer, the quality of the cationic asphalt emulsion decomposer may be reduced. On the other hand, if the weight proportion of other components exceeds 50 wt%, the effects of the present invention may be insufficient.

[0040] [Method for producing a decomposer for cationic asphalt emulsion] The method for producing the decomposing agent of the present invention is not particularly limited as long as no undissolved or undispersed components remain and the agent is uniformly dissolved or dispersed. For example, the following methods can be mentioned. (1) A method in which the sulfur-containing anionic surfactant (A), the sulfur-containing inorganic salt (B), the compound (C), and the carboxylic acid salt having 6 or more carbon atoms (D) are added little by little to water and / or a solvent under stirring and mixed. (2) A method in which the sulfur-containing inorganic salt (B) is dissolved in water and / or a solvent while stirring, and then the sulfur-containing anionic surfactant (A), the compound (C), and the carboxylic acid salt having 6 or more carbon atoms (D) are added little by little while stirring thoroughly and mixed. (3) A method in which (a) is a solution in which the sulfur-containing anionic surfactant (A), the compound (C), and the carboxylic acid salt having 6 or more carbon atoms (D) are dissolved in water and / or a solvent at a high concentration, and (b) is a solution in which the sulfur-containing inorganic salt (B) is dissolved in water at a high concentration is separately prepared, and (b) is added little by little while thoroughly stirring (a) and mixed. (4) A method in which the sulfur-based anionic surfactant (A), the sulfur-containing inorganic salt (B), the compound (C), and the carboxylic acid salt having 6 or more carbon atoms (D) are dissolved in water and / or a solvent at high concentrations separately and then mixed while thoroughly stirring.

[0041] [Method of spraying asphalt emulsion decomposer] The method for spraying the decomposing agent for asphalt emulsion of the present invention is a spraying method in which the decomposing agent of the present invention is brought into contact with the cationic asphalt emulsion. The decomposing agent for the asphalt emulsion may be sprayed simultaneously with the asphalt emulsion, or may be sprayed on top of the asphalt emulsion after it has been sprayed. Asphalt emulsions are sprayed onto road subgrades, base layers, and surface layers, and are also used for spray-on waterproofing of slopes, walls, etc., and since the decomposer of the asphalt emulsion of the present invention has excellent instantaneous decomposition properties, it can also be used for these purposes. When spraying, it is preferable to spray in mist form to ensure uniformity without any spots. For example, for small-scale paving, an engine sprayer, gear sprayer, air sprayer, hand sprayer, airless pump sprayer, etc. may be used, and for large-scale paving, equipment for spraying asphalt emulsion such as an asphalt sprayer, asphalt distributor, or asphalt finisher with emulsion spraying function may be used. The amount of decomposing agent to be sprayed is preferably 10 parts or more per 100 parts of the emulsion, from the viewpoint of excellent decomposition of the asphalt emulsion at low temperatures. [Example]

[0042] [Production of decomposing agent] Decomposers for cationic asphalt emulsions of Examples 1 to 22 and Comparative Examples 1 to 11 were produced by the method (3) above so as to have the mass ratios shown in Tables 1 to 5. The specific gravity and viscosity of the decomposing agent in each of the cationic asphalt emulsions of Examples 1 to 22 and Comparative Examples 1 to 11 were measured as follows, and the results are shown in Tables 1 to 5. The decomposition test of the asphalt emulsion was carried out as follows, and the test results are shown in Table 6.

[0043] 〔specific gravity〕 The specific gravity of the decomposing agent in the cationic asphalt emulsion at a temperature of 20°C was measured in accordance with the method described in JIS-Z8804-9. Density and specific gravity meter: Kyoto Electronics Manufacturing Co., Ltd. DA-200

[0044] 〔viscosity〕 The viscosity of the decomposer for the cationic asphalt emulsion at a temperature of 20°C was measured using a Brookfield viscometer.

[0045] [Asphalt emulsion decomposition test] On a slate board measuring 150mm long x 150mm wide x 3mm thick, 0.4L / m of cationic asphalt emulsion PK-4 was applied. 2 The test base was then evenly coated and allowed to dry naturally. The test base was then cured for at least four hours in thermostatic chambers at 5°C and 20°C, and the cationic asphalt emulsion and decomposer were cured for at least four hours in a thermostatic chamber at 20°C. 0.4L / m of cationic asphalt emulsion PK-4 was applied to the test base cured at each temperature. 2 The asphalt emulsion was applied to the sample, and then a decomposition agent in an amount of 10 wt% of the asphalt emulsion amount was quickly sprayed onto the sample from above using a sprayer. The sample was then returned to the thermostatic baths at 5°C and 20°C and allowed to stand. The state of decomposition of the emulsion was observed immediately after the start of the test and after 1 minute, 3 minutes, 5 minutes, and 10 minutes. ○ Asphalt has formed a film and is decomposed down to the lower layer △ 1 The surface is decomposed and forms a film, but the underlying layer contains undecomposed emulsion. △ 2 Decomposition occurs down to the bottom layer, but no film is formed and the aggregates settle. × Asphalt does not form a film and undecomposed emulsion remains If the asphalt emulsion had decomposed down to the lower layer within 10 minutes and formed a film, the test was deemed to have passed. If the asphalt emulsion had not decomposed even after 10 minutes or if the separated asphalt had not formed a film, the test was deemed to have failed.

[0046] The molecular weight and solubility (g / 100g) in 100g of water at 20°C of the compound (C) in the table are as follows. POP(2) methyl ether Molecular weight: 148 Solubility: >100 POP(2) propyl ether Molecular weight: 176 Solubility: 5.0 POP(1) butyl ether Molecular weight: 132 Solubility: 6.8 POP(2) butyl ether Molecular weight: 190 Solubility: 3.1 POE(3)POP(5) butyl ether Molecular weight: 497 Solubility: 16.0 POE(4)POP(12) butyl ether Molecular weight: 947 Solubility: 0.3 POP(1) phenyl ether Molecular weight: 152 Solubility: 0.2 POP(3) phenyl ether Molecular weight: 268 Solubility: <0.1 Polypropylene glycol 2000 Molecular weight: 2000 Solubility: <0.1

[0047] [Table 1]

[0048] [Table 2]

[0049] [Table 3]

[0050] [Table 4]

[0051] [Table 5]

[0052] [Table 6]

[0053] As can be seen from Tables 1 to 6, the decomposers for cationic asphalt emulsions according to Examples 1 to 22 contain a sulfur-containing anionic surfactant (A), at least one sulfur-containing inorganic salt (B) selected from sulfates, sulfites, hydrogen sulfites, and thiosulfates, and a compound (C) represented by the general formula (1) above, and have a specific gravity of 1.03 to 1.30 at 20°C, thereby solving the problem of the present application. On the other hand, the problems of the present application cannot be solved because there is no sulfur-containing inorganic salt (B) (Comparative Examples 1, 3, 5, and 8), no sulfur-containing anionic surfactant (A) (Comparative Examples 2, 3, 6, and 7), no compound (C) (Comparative Examples 1, 2, 4, 9, and 10), and the specific gravity is low (Comparative Examples 1, 3, 5, and 11).

Claims

1. A decomposer for cationic asphalt emulsions, comprising (A) a sulfur-containing anionic surfactant, (B) at least one sulfur-containing inorganic salt selected from sulfates, sulfites, hydrogen sulfites, and thiosulfates, and (C) a compound represented by the following general formula (1), and having a specific gravity at 20°C of 1.03 to 1.30: RO-[(PO)p / (EO)q]-H (1) (In formula (1), R represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkenyl group having 1 to 8 carbon atoms, a phenyl group, an alkylphenyl group having 7 to 15 carbon atoms, an alkoxyphenyl group having 7 to 15 carbon atoms, or a benzyl group. PO represents an oxypropylene group, and EO represents an oxyethylene group. p and q represent the average number of moles added, where p=1 to 40, q=0 to 39, and p+q=1 to 40. [(PO)p / (EO)q] represents a polyoxyalkylene group formed by the addition of p moles of PO and q moles of EO. The addition of PO and EO may be either a random addition or a block addition.) (However, when R is a hydrogen atom, p=2 to 40, q=0 to 39, and p+q=2 to 40.)

2. The decomposing agent according to claim 1, wherein the surfactant (A) is a mixture of two or more kinds and essentially contains an aromatic sulfonate.

3. The decomposing agent according to claim 1 or 2, wherein the compound (C) has an average molecular weight (Mw) of 1,000 or less.

4. The decomposition agent according to claim 1 or 2, wherein the solubility of the compound (C) in 100 g of water at 20°C is 20 g or less.

5. The decomposing agent according to claim 1 or 2, further comprising a carboxylic acid salt (D) having 6 or more carbon atoms.

6. The decomposing agent according to claim 5, wherein the weight ratio of the surfactant (A) is 0.1 to 40% by weight, the weight ratio of the sulfur-containing inorganic salt (B) is 0.1 to 20% by weight, and the total weight ratio (C+D) of the compound (C) and the carboxylate (D) is 0.1 to 40% by weight, relative to the weight of the decomposing agent.

7. A method for spraying an asphalt emulsion, comprising contacting a cationic asphalt emulsion with the decomposing agent according to claim 1 or 2.

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