JPH0331340A - Asphalt emulsion - Google Patents

Abstract

PURPOSE:To provide the subject emulsion having good penetrability and safe workability and suitable for repairing the cracks of asphalt-paved roads, etc., by mixing an asphalt emulsion with an anionic emulsion in a specific solid content weight ratio. CONSTITUTION:(A) An asphalt emulsion and/or a rubber.asphalt emulsion are mixed with (B) an anionic copolymer emulsion in a solid content weight of A:B=99:1-50:50 to provide the objective emulsion, the anionic copolymer emulsion being prepared by copolymerizing an acrylic acid compound and/or a methacrylic acid compound with vinyl acetate in the presence of an acidic catalyst and subsequently adjusting the pH of the product with an alkali to 7 or larger. (C) A rubber latex is preferably further mixed with the components A and B in a solid content weight ratio of A:(B+C)=99:1-70:30.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to an asphalt-based emulsion suitable for repairing cracks in concrete and asphalt-paved roads.

(Prior Art) Conventionally, cracks in asphalt-paved roads have been repaired by pouring molten asphalt, molten asphalt mixed with rubber latex, or asphalt emulsion.

However, with this method, the molten asphalt that enters the crack immediately cools and solidifies, making it impossible to fill the tip of the crack, leaving only the area near the surface of the road closed. The strength of the parts is weak and cracks are likely to occur again.

Furthermore, since the temperature range in which it can be used is narrow, from about 5°C to 35°C, it tends to melt in the summer and easily cracks in cold regions. Furthermore, molten asphalt mixed with rubber latex is manufactured by dropping asphalt heated to about 100°C into the rubber latex little by little, making it difficult to work with. It also has the disadvantage of being highly dangerous.

Furthermore, asphalt emulsions require more than a week to harden, and since the water content is about 50% by weight, the volume decreases significantly after hardening, often requiring repair, and the flow temperature is low. Therefore, rutting etc. are likely to occur.

On the other hand, concrete, concrete milk, mixtures of concrete and resin, etc. have traditionally been used for repairing cracks in concrete in buildings, tunnels, underpasses, etc., and as binding agents for concrete and steel, but these are often used for drying purposes. The problem is that it takes time.

Furthermore, in recent years, crack repair materials for asphalt pavement have been proposed that are made by blending rubber latex with asphalt emulsion. It has the disadvantage that in order to dry it, it is necessary to accelerate dehydration and drying by heating. In addition, if the repair material is thick, only the surface hardens and the inside does not harden, and furthermore, there is a large volume reduction after drying, and there are drawbacks such as severe deterioration due to heat and ultraviolet rays and poor weather resistance.

In addition to the general-purpose water-stopping materials mentioned above, silicone-based waterstopping materials,
Epoxy-based water-stopping materials, water-absorbing polymer-based water-stopping materials, or cutback asphalt made by dissolving asphalt in a specific organic solvent are used as water-stopping materials and crack repair agents, but silicone-based water-stopping materials, Epoxy-based water-stopping materials have disadvantages such as poor permeability and inability to fill to the tip of cracks, poor adhesion, and high cost, while water-absorbing polymer-based waterstopping materials harden into a gel-like state. Extremely fragile;
It has drawbacks such as poor cold resistance and heat resistance, and furthermore, cutback asphalt has drawbacks such as poor cold resistance and heat resistance.

Furthermore, in recent years, repair materials have been developed that improve strength by mixing cationic asphalt emulsions with cationic emulsions of acrylic acid or methacrylic acid polymers, but these repair materials cure too quickly and crack. There were problems in that it was not possible to fully fill the tip of the emulsion, and the state of the emulsion was unstable, resulting in poor workability.

As described above, various materials have been proposed as water supply materials and crack repair agents, but it is still difficult to find a material that fully satisfies various properties such as permeability, cold resistance, high rubber elasticity, and appropriate curing speed. The current situation is that this is not the case.

(Problems to be Solved by the Invention) The present invention enables filling up to the tips of cracks, increases rubber elasticity, expands the applicable temperature range, can withstand use in cold regions, and penetrates into cracks. The object of the present invention is to provide an asphalt emulsion having a solidification time suitable for the work.

[Structure of the Invention] (Means for Solving the Problems) The asphalt emulsion of the present invention comprises (a) an asphalt emulsion and/or a rubber/asphalt emulsion;
(b) An anionic emulsion of a copolymer obtained by polymerizing an acrylic acid compound and/or a methacrylic acid compound and vinyl acetate in the presence of an acidic catalyst and having a pl+ of greater than 7 with an alkali, (a): ( b) is 99:1-5
(a): (b) + (c
) is 99+1 to 70:30 solid molecule f! It is characterized by being mixed so that the ffi ratio is achieved.

First, the anionic asphalt emulsion and rubber asphalt emulsion (a) used in the present invention will be explained. (Hereinafter, all ffi' parts and weight ratios are based on solid content.) The anionic asphalt emulsion is made of natural asphalt,
It is made by melting asphalt such as petroleum asphalt and emulsifying it using an anionic surfactant, which has the advantage of allowing sufficient working time and penetration time to solidify and making repair work easier. As an anionic rubber or asphalt emulsion, asphalt 100 parts by weight of rubber latex (hereinafter simply referred to as "parts") is heated and melted.
A high concentration emulsion containing 0 to 1200 parts of water and an anionic surfactant and a dispersion stabilizer with a water content of 8 to 35% by weight (hereinafter simply referred to as %) is suitable. The rubber latex used in the above high concentration emulsion is S[3R, vinylpyridine SBR.

Carboxy-modified SBI? , NBR latex is available.

The asphalt may be either natural asphalt or petroleum asphalt, and straight asphalt, blown asphalt, and others may be used alone or in combination. The temperature at which these asphalts are added to the rubber latex is preferably in the range of 70 to 150°C from the viewpoint of dispersibility and stability of the rubber latex.

Examples of anionic surfactants include fatty acid salts, higher alcohol sulfate ester salts, alkylbenzene sulfonates, and rosinates.

Dispersion stabilizers include inorganic ones such as bentonite and clay, and organic ones such as polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, sodium polyacrylate, starch, and casein, which can be used alone or in combination. This improves the stability of the resulting rubber/asphalt emulsion.

The anionic emulsion of a copolymer of an acrylic acid compound and/or a methacrylic acid compound and vinyl acetate of the present invention can be produced by adding an acidic catalyst such as ammonium persulfate to a mixture of these compounds, water, and an emulsifier, and then adding an acidic catalyst such as ammonium persulfate to the mixture with hot water. It can be obtained by polymerizing by stirring in an aqueous solution, followed by neutralization with alkali such as aqueous ammonia to make pi greater than 7 and stopping the reaction.

As acrylic acid compounds and methacrylic acid compounds,
Acrylic acid, acrylic acid ester, sodium polyacrylate, acrylate monomers dimethylaminoethyl acrylate, isobutyl acrylate, diethylene glycol ethoxylate acrylate, 2-ethoxyethyl acrylate, epoxy acrylate, n-ester acrylate, tetrahydrofurfuryl acrylate, trimethylolpropane triacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 1,4-butanediol diacrylate,
1,6-hexanediol diacrylate, pentaerythritol triacrylate, lauryl-tridecyl (
Mixed) acrylate, methyl methacrylate (t-butyl methacrylate, 2-ethylhexyl methacrylate, tridecyl methacrylate, stearyl methacrylate, cyclohexyl methacrylate, methacrylic acid, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, tetrahedron) Furfuryl methacrylate, ethylene dimethacrylate, tetraethylene glycol dimethacrylate, 1,3-butylene dimethacrylate, trimethylolpropane trimethacrylate, glycidyl methacrylate, n-butyl methacrylate, inbutyl methacrylate, 2-hydroxyethyl methacrylate , lauryl methacrylate, etc.

The weight ratio of each compound to be copolymerized is preferably in the range of 10:90 to 90:10: acrylic acid compound and/or methacrylic acid compound: vinyl acetate (monomer); if the vinyl acetate component is larger than this, polyvinyl acetate Since the number of parts increases, the hardness of the solidified product obtained will not be sufficient. Conversely, if the vinyl acetate component is less than this, the hardness will be too high.

The rubber latex (c) used in the present invention includes:
There are latexes such as styrene-butadiene copolymer (SBR), vinylpyridine SBR, carboxy-modified SBR, acrylonitrile-butadiene copolymer (NBI?), and natural rubber. As the SBR latex, it is desirable to use SBR latex and carboxy-modified SBR latex alone or in combination. When mixing, increasing the proportion of carboxy-modified SBR latex increases the tensile strength and elasticity of the resulting asphalt emulsion after solidification, so the blending ratio may be changed as appropriate depending on the application.

(b) an anionic emulsion of the copolymer; and (c)
The mixing ratio with rubber latex is (b):(c) -1
:10G to 240:10G (solid content weight ratio, same below) is appropriate, and lO:100 to 120:100
is more preferable.

Also, the mixing ratio of (a) asphalt emulsion etc. and (b) anionic emulsion is (a):(b) -99
:1 to 50:50, asphalt emulsion etc. of (a) and (b)
The mixing ratio of the anionic emulsion in ) and the rubber latex in (c) is (a): (b) + (c) -99:1 ~
The solids weight ratio is 70:30.゛If the amount of component (b) alone or the total amount of components (b) and (c) is greater than this, the solidification rate of the resulting asphalt-based emulsion will become too fast, making it impossible to inject into cracks. If the amount is less, the assimilation time will take too long (more than a week), which is undesirable.

In addition, in the present invention, in order to further improve weather resistance, cold resistance, and flexibility, anti-aging agents and plasticizers may be added at a rate of 5% by weight or less of the rubber component of the asphalt emulsion obtained. can. 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.)
etc. In addition, as hardening accelerators, extenders, or thickeners, alumina, magnesia, metal oxides such as iron oxide, metal powders, stone powder (calcium carbonate powder), crushed stone powder, gravel, wood powder (rice husks, sawdust, etc.) ), cement, clay, and other fillers can be added at a rate of 10% or less of the solid content of the resulting asphalt emulsion.

When filling cracks in roads with the asphalt emulsion of the present invention, a mixture of the above-mentioned components may be injected into the cracks using a nozzle, hose, etc. just before filling or several days before filling.

(Function) The asphalt emulsion of the present invention has the above-mentioned copolymer emulsion, rubber latex, etc. added to the asphalt emulsion, etc., so that the solidification time of the asphalt emulsion is appropriately adjusted, and the solidification time of the asphalt emulsion is adjusted appropriately, so that the asphalt emulsion can be applied to the tips of cracks on the road surface, etc. It is possible to reliably fill up to 100%, and also to cure within an appropriate amount of time. Furthermore, due to the presence of copolymer emulsion, rubber latex, etc., the solidified product exhibits excellent properties such as rubber elasticity and cold resistance.

Further, by adjusting the emulsion to be anionic, the stability of the emulsion can be improved and a stable state can be maintained for a long period of time.

(Example) Examples of the present invention will be described below.

Examples 1 to 9 Asphalt emulsions were prepared by mixing each component in the formulation shown in the following table. In addition, each component used was adjusted as follows.

Asphalt emulsion Niasphald is heated and melted, poured into water in which an anionic surfactant has been dissolved, at a ratio of asphalt:water of 50:50, and stirred and dispersed.

Rubber/asphalt emulsion: 100 parts of heat-eluted asphalt is poured into 100 parts of rubber latex (solid content: 50%), and an anionic surfactant and a dispersion stabilizer are added to the mixture, followed by stirring and dispersion.

Copolymer emulsion *1: Dissolve 10 parts of methyl methacrylate monomer and 10 parts of vinyl acetate monomer in 20 parts of water, add 4 parts of surfactant and 1 part of ammonium persulfate as a polymerization catalyst, After stirring at ~90°C for 8 hours and polymerizing, aqueous ammonia was poured to bring the pl+8.5
adjusted to.

Copolymer emulsion *2 10 parts of methyl acrylate monomer and 10 parts of vinyl acetate monomer are dissolved in 20 parts of water, 4 parts of surfactant and 1 part of ammonium persulfate as a polymerization catalyst are added, and 85~ After stirring at 90°C for 0 hours and polymerizing, aqueous ammonia was added to adjust the PL to +8.5.

SBR latex: solid content 50%, glass transition point -69
℃.

NBR latex: solid content 50%, glass transition point -55
℃.

Methyl methacrylate emulsion: Dissolve 10 parts of methyl methacrylate monomer in 10 parts of water, add 2 parts of surfactant and 0.5 part of ammonium persulfate as a polymerization catalyst, and stir at 85-90°C for 6 hours. , After polymerization, the pH was adjusted to 8.5 by pouring aqueous ammonia.

For comparison, as shown in Comparative Example in the table, asphalt emulsions were prepared by mixing each component in a ratio different from the composition of the present invention.

Next, various tests were conducted on the asphalt emulsions obtained in the Examples and Comparative Examples using the following methods.

Penetration and softening point: JIS K 22085.13
1: Measured in the same manner.

Glass transition point: Measured using a differential scanning calorimeter.

Solidification time: 20g of a sample was placed in a plastic container with a volume of 200cc, and the time required for solidification when left in the air (about 23°C) was measured.

Weather resistance: A sample with a thickness of 3a+m was placed on a disk with a diameter of 15o+s, and exposed outdoors while leaning at an angle of 45@, and the presence or absence of cracks was examined.

The results of these measurements are shown in the lower column of the table below.

(The following is a blank space) As shown in the same table, the asphalt emulsion of the present invention has an appropriate solidification time, and the solidification time can be easily adjusted by changing the mixing ratio of each component.

Furthermore, since the difference between the glass transition point and the softening point is large, it can be applied over a wide temperature range and has excellent weather resistance.

[Effects of the Invention] Since the asphalt emulsion of the present invention is configured as described above, it exhibits the following effects.

When an asphalt emulsion is used as component (a), it has good permeability and is safe to work with, and when a rubber asphalt emulsion is used, in addition to these effects, the softening point of the solidified product, Rubber elasticity and weather resistance are further improved,
It fully demonstrates its characteristics even in the summer. In addition, since a copolymer emulsion of an anionic acrylic acid compound and/or methacrylic acid compound and vinyl acetate is used as the main ingredient, the time required for drying and solidification is significantly shortened and cold resistance is improved. .

Furthermore, when rubber latex is used together with these curing agents, the proportion of rubber components in the emulsion increases, so mechanical properties such as elasticity are further improved, and cracks are less likely to occur even when external forces are applied.

Claims (2)

[Claims] (1) (a) Asphalt emulsion and/or rubber/asphalt emulsion, (b) acrylic acid compound and/or methacrylic acid compound, and vinyl acetate are polymerized in the presence of an acidic catalyst, and the pH is increased to higher than 7 with an alkali. (a):(b)=
An asphalt emulsion characterized by being mixed at a solid content weight ratio of 99:1 to 50:50. (2) Polymerize (a) an asphalt emulsion and/or a rubber/asphalt emulsion, (b) an acrylic acid compound and/or a methacrylic acid compound, and vinyl acetate in the presence of an acidic catalyst, and then raise the pH to more than 7 with an alkali. An anionic emulsion of the copolymer and (c) rubber latex, (a):(b)+(c)=99:1 to 70:3
An asphalt emulsion characterized by being mixed at a solid content weight ratio of 0.