JPH04370153A - Asphalt admixture - Google Patents

Abstract

PURPOSE:To provide the title admixture rapid in setting rate in general, also capable of easily regulating said setting rate, thus quickly responsive to the change in application or working environment. CONSTITUTION:The objective admixture comprising (A) an asphalt-based emulsion and (B) a liquid polybutadiene having at least one kind of functional group selected from hydroxyl, isocyanate and epoxy groups at the main chain terminals.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an asphalt mixture suitable for repairing cracks in concrete structures and asphalt-paved roads, and more particularly to an asphalt mixture whose curing time and pot life can be easily adjusted.

0002

[Prior Art] Conventionally, molten asphalt, molten asphalt mixed with rubber latex, which is a mixture of molten asphalt with rubber latex, or molten asphalt dispersed in water using an emulsifier, have been used as joint materials and crack repair materials for concrete structures and asphalt-paved roads. Asphalt emulsions are commonly used.

However, since molten asphalt cools and solidifies immediately after injection, it has the disadvantage that it cannot sufficiently fill the deep parts of cracks, and molten asphalt mixed with rubber latex has poor workability and is difficult to work with. The problem was that it was dangerous.

On the other hand, asphalt emulsions have the advantage of being easy and safe to handle, as well as having excellent permeability and being able to sufficiently fill the depths of cracks. However, on the other hand, the curing time is usually longer than one week, and the moisture content is high, resulting in a significant volume reduction after curing, which often requires repair. There was also the problem that if it rained immediately after injection, the emulsifier would separate and flow out through the cracks.

[0005] Various studies have therefore been made to increase the curing speed of asphalt emulsions, and methods have been developed, for example, of incorporating inorganic electrolytes, acid anhydrides, etc. as curing agents.

[0006]

[Problems to be Solved by the Invention] Regarding the curing speed, depending on the application, there are cases where a quick curing of about 1 minute is required, and there are cases where a pot life of about 30 to 60 minutes is required. Furthermore, the curing speed is often affected by the construction environment conditions; for example, in the summer,
In the winter, the pot life may extend to about 120 minutes and the curing time may extend to about 240 minutes. From this point of view, it is desirable for materials such as crack repair materials to have curing speeds that can be easily controlled depending on the application and environmental conditions, and that do not cause any inconvenience such as deterioration of the properties of the cured product. .

However, in the conventional technology as described above, since the curing agent has the property of disrupting the balance of emulsification and exerting a curing effect, a slight change in the amount of the curing agent may result in uncured or instantaneous curing. There was a problem in that it was difficult to adjust the curing time, such as curing.

The present invention has been made to address the problems of the prior art, and has a generally fast curing speed, and
The object of the present invention is to provide an asphalt mixture whose curing speed can be easily adjusted according to changes in the use or working environment without causing any inconvenience.

[0009]

[Means for Solving the Problems] The asphalt mixture of the present invention comprises (A) an asphalt emulsion and (B) at least one functional group selected from a hydroxyl group, an isocyanate group, and an epoxy group at the end of the main chain. It is characterized by being mixed with liquid polybutadiene.

The asphalt emulsion (A) used in the present invention is a component forming the main ingredient of the asphalt mixture of the present invention, and is an asphalt obtained by melting asphalt such as natural asphalt or petroleum asphalt and emulsifying it with an emulsifier. Examples include emulsions and rubber/asphalt emulsions in which heated and melted asphalt is blended with rubber latex and emulsified by mixing an emulsifier and a dispersion stabilizer. The water content is preferably about 50% by weight.

[0011] Examples of the asphalt include natural asphalt, petroleum asphalt, straight asphalt, blown asphalt, etc., which may be used alone or in combination. Examples of the rubber latex include styrene-butadiene copolymer (SBR), vinylpyridine SBR, carboxy-modified SBR, and acrylonitrile-butadiene copolymer (NBR), which may be used alone or in combination. The emulsifier may be any of anionic, cationic, and nonionic emulsifiers. Examples of anionic emulsifiers include fatty acid salts, higher alcohol sulfate ester salts, alkylbenzene sulfonates,
Examples of cationic emulsifiers include primary, secondary, and tertiary alkyl amine salts, and quaternary ammonium salts. Examples of nonionic emulsifiers include higher alcohols, higher Examples include fatty acid amines. Dispersion stabilizers include inorganic ones such as bentonite and clay, and organic ones such as polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, and polyacrylic acid soda. , starch, casein, etc. These are used alone or in combination to improve the stability of the resulting rubber/asphalt emulsion.

In addition to the above-mentioned components, the above-mentioned asphalt emulsion contains an anti-aging agent and a plasticizer in an amount of 5% or less of the rubber component in order to improve weather resistance, cold resistance, flexibility, etc. It can be added at a ratio of Examples of plasticizers include polybutene-1, phthalate ester compounds (dioctylhexyl phthalate, dimethyl phthalate, etc.), aliphatic dibasic acid ester compounds (diisodecyl succinate, etc.), and glycol ester compounds (diethylene glycol dibenzoate, etc.). ), fatty acid ester compounds (butyl oleate, etc.), phosphate ester compounds (
tricresyl, etc.). In addition, as hardening accelerators, extenders, or thickeners, metal oxides such as alumina, magnesia, and iron oxide, metal powders, stone powder (calcium carbonate powder), crushed stone powder, gravel, and wood powder (rice husks, sawdust, etc.) , cement, clay, and other fillers may be added within a range that does not impede the effects of the present invention.

The liquid polybutadiene (B) used in the present invention has a molecular weight of at least one functional group selected from a hydroxyl group, an isocyanate group, and an epoxy group at one or both ends of the polybutadiene main chain. It is a liquid product with a weight of about 1,000 to 3,500. Examples of such liquid polybutadiene having isocyanate groups at both ends include polybutadiene HTP-4 having a molecular weight of 3000 represented by formula (I), polybutadiene HTP-5M having a molecular weight of 3200 represented by formula (II);
Assuming that LD etc. has a hydroxyl group at both ends, the formula
Polybutadiene R-45HT with a molecular weight of 2800 represented by (III) and polybutadiene R-45HT with a molecular weight of 1200
15HT, and polybutadiene R-45EPT having a molecular weight of 2900 represented by the formula (IV) as a material having epoxy groups at both ends, which can be used alone or in combination. The liquid polybutadienes exemplified above are all trade names manufactured by Idemitsu Petroleum Science Co., Ltd.

[0014]

[Chemical formula 1]

[0015]

[Case 2]

[0016]

[Chemical formula 3]

[0017]

[C4]

This (B) liquid polybutadiene is (A
) has the role of a curing agent for asphalt emulsions, and by adding it to O/W type (oil particles dispersed in water) emulsions like the above asphalt emulsions, it can harden the terminal hydroxyl groups. Water hydrates in oil, chemically destroys the hydration layer, inverts the phase from O/W type to W/O type (water particles dispersed in oil), and the overall It is thought that it hardens quickly. Furthermore, the curing speed can be controlled by adjusting the amount of compounding, and this adjustment is easy.As with conventional hardening agents such as electrolytes, a slight change in the amount can significantly increase the curing time. On the other hand, there is no risk of instant hardening. In addition, the curing rate tends to be generally high for those having an isocyanate group at the end, and generally low for those having a hydroxyl group at the end. Therefore, by selecting the type and changing the blending amount, it is possible to obtain a desired curing time depending on the application and work environment.

The amount of liquid polybutadiene (B) is 10% of the solid content of the asphalt emulsion (A).
A range of 1 to 40 parts by weight per 0 parts by weight is suitable,
Within this range, the curing time can be controlled without impairing properties such as mechanical strength and elongation of the resulting cured product.

To obtain the asphalt mixture of the present invention,
The liquid polybutadiene (B) may be added as is to the asphalt emulsion (A) prepared in advance and mixed. It may also be added to and mixed with the asphalt emulsion. In this case, the solvent is preferably one that has low compatibility with water and does not react with the hydroxyl group, isocyanate group, or epoxy group at the end of the polybutadiene, such as ethyl acetate, butyl acetate,
Octyl acetate, cyclohexyl acetate, esters such as their acetylated products, dioctyl phthalate (DOP)
), dioctyl adipate (DOA), dioctyl sebacate (DOS), diisodecyl phthalate (DIDP
), oil-based solvents such as liquid paraffin and process oil, and non-polar solvents such as xylene, toluene, benzene, hexane, and hexanone.

[0021] The asphalt mixture of the present invention starts phase inversion curing at a curing rate largely based on the type and amount of liquid polybutadiene (B) as well as the mixing of the components, so that the asphalt mixture as a whole is uniform and sufficient. Cures with mechanical strength. This cured body is completely cured as the water inside further evaporates over time, forming a solidified body having excellent properties including mechanical properties.

[0022]

[Operation] In the asphalt mixture of the present invention, due to the curing action of the liquid polybutadiene (B), the phase changes from an O/W type with water as a matrix to a W/O type with an asphalt component as a matrix, and the entire mixture is rapidly is cured uniformly and with sufficient mechanical strength, but the curing action of liquid polybutadiene (B) is different from that of conventional curing agents;
By hydration of water to functional groups such as terminal hydroxyl groups,
Because the hydration layer is chemically destroyed,
By changing the blending amount, the curing time and pot life can be easily adjusted, and there is no risk of uncured or instantaneous curing. Further, the properties of the cured product do not deteriorate.

[0023]

[Examples] Examples of the present invention will be described below. Examples 1 to 14 Asphalt mixtures were prepared by mixing each component in the formulations shown in Tables 1 and 2. In Examples 5 to 14, liquid polybutadiene previously dissolved in a solvent was added to and mixed with the asphalt emulsion.

Next, the phase inversion curing time of each of the obtained asphalt mixtures was examined, and the elongation after curing was measured. The phase inversion curing time was determined by placing 30 g of the asphalt mixture in a 100 cc plastic container and measuring the time required for phase inversion curing when the mixture was left at 30°C. Also, the elongation is J
It was measured by the elongation measurement method of IS K 2208. The results are shown in the lower column of Table 1. For comparison, the two types of asphalt emulsions used in the examples (anionic rubber asphalt emulsion and cationic asphalt emulsion) were each used alone.
Phase inversion curing was attempted under the same conditions as in the examples. The result was that it remained uncured even after 3 days.

[0025]

[Table 1]

As is clear from Table 1 and the results of the comparative examples, the asphalt mixture of the present invention has different phase inversion curing times depending on the type and amount of liquid polybutadiene. Therefore, by appropriately selecting the type of liquid polybutadiene and changing its blending amount, it is possible to easily adjust from near-instant curing to relatively long curing time and pot life, depending on the purpose and application. can.

[0027]

As explained above, the asphalt mixture of the present invention comprises an asphalt emulsion and a liquid polybutadiene having at least one functional group selected from hydroxyl group, isocyanate group and epoxy group at the end of the main chain. The mixture generally cures in a short period of time, but the curing time can be adjusted by changing the amount of liquid polybutadiene as appropriate depending on the type of liquid polybutadiene. There is no risk of hardening. Therefore, it is possible to quickly respond to changes in usage and work environment.

Claims (1)

[Claims] Claim 1: (A) an asphalt emulsion; (B)
An asphalt mixture comprising a liquid polybutadiene having at least one functional group selected from a hydroxyl group, an isocyanate group and an epoxy group at the end of the main chain.