JPH08231826A - Asphalt emulsion additive and cold-mixing asphalt composition - Google Patents

Abstract

PURPOSE: To obtain a cold-mixing asphalt compsn. excellent in pavement strength, durability, and water resistance by compounding an asphalt emulsion with a prepolymer which slowly resinifies in an aq. soln. CONSTITUTION: A formaldehyde condensate of a compd. represented by formulas I, II, III, or IV (wherein R1 , R3 , and R4 are each H or 1-9C alkyl; R2 is H or OH; RO is 2-3C oxyalkylene; n is 0-100; Z is H or SO3 X1 ; X1 and X2 are each H, a mono- or divalent metal, ammonium, etc.; and Y1 , Y2 , and Y3 are each H, CH2 OH, etc), etc., and a monomer cocondensable with these monomers or a salt of the condensate is used as an asphalt emulsion additive. The condensate its salt is a prepolymer having a wt. average mol.wt. of about 300-50,000 and is used pref. in an amt. of 0.5-50wt.% of the solid content of an asphalt emulsion in order to maintain sufficient binder strength, adhesion to aggregates, and flexibility. A catalyst is used for resinification, pref. an org. acid ester.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an asphalt emulsion additive and a room temperature mixing asphalt composition which can be applied to various applications such as a binder for pavement, a waterproofing agent and an adhesive.

[0002]

BACKGROUND OF THE INVENTION Bituminous substances such as asphalt obtained from petroleum are emulsified into pavement materials, waterproof and adhesive so that they can be handled at room temperature in order to provide workability. Widely used in materials and railway tracks. In addition, since the heating and mixing method heats asphalt and aggregates to around 150 ° C during manufacturing, carbon dioxide gas (main causative agent of global warming) from fuel and harmful gas from asphalt are generated, which is environmentally friendly. Also, it is preferable to use it in the form of an emulsion.

However, since the conventional asphalt composition using the asphalt emulsion has drawbacks such as pavement strength, durability, and weak water resistance as compared with the heating and mixing method, its range of use is limited, and thus heating by heating is difficult. It has been desired to develop an asphalt emulsion composition for room temperature pavement, which has an improved strength and durability as an alternative to the mixing method. The cause of the low strength of the asphalt emulsion composition is considered as follows. That is, in the asphalt emulsion composition, the asphalt particles finely emulsified in water become unstable due to evaporation of water, etc., and develop strength by coalescence, but coalescence is insufficient or coalescence is difficult. It is considered that the emulsifiers remaining in the asphalt and the water that was not completely removed become defects and the strength is reduced.

[0004] Conventionally, as a method for improving the drawbacks of these asphalt emulsions, for example, JP-A-2-206655 proposes a method of adding rubber or the like to the asphalt for the purpose of improving the strength of the asphalt. However, in these methods, since the asphalt has a hard property, coalescence of the asphalt particles hardly occurs at room temperature, and as a result, the strength of the asphalt composition has not been improved.

Further, the stability of asphalt emulsion varies depending on the type of emulsifier (a kind of surfactant) used and the material of the aggregate used, and the rate of strength development is slow because it depends on the rate of water removal. Problems such as this have also been pointed out.

[0006]

Means for Solving the Problems The inventors of the present invention have eagerly studied to improve the above-mentioned problems, and as a result, have clarified the cause of the strength reduction of an asphalt composition using an asphalt emulsion, and based on the findings, The inventors have completed an additive for asphalt emulsion and an asphalt composition capable of exhibiting strength equal to or higher than that of a heat-mixing type asphalt composition and controlling the rate of strength development.

That is, the present invention relates to an additive for an asphalt emulsion, which is characterized in that a water-soluble prepolymer, which undergoes a reaction gradually in an aqueous solution to form a resin, is an essential component, and an asphalt composition for room temperature mixing. It is a thing.

The asphalt composition generally comprises an asphalt emulsion optionally mixed with a filler such as stone powder, sand, gravel (including crushed stone) and the like. In an asphalt composition using an asphalt emulsion, water is removed by some method so that the asphalt particles are united with each other and strength is developed. However, the strength of the asphalt composition is reduced due to insufficient coalescence of the asphalt particles or defects caused by remaining water. Here, the present inventors
Focusing on the fact that the defects generated by the asphalt emulsion are due to the presence of water, by filling the space where water is present and the space where water was present with a substance that is stronger than asphalt, the strength of the asphalt composition It was found that the strength development rate of the asphalt composition, which was another problem, can be freely controlled by controlling the strength development rate of the space portion by a chemical reaction.

The water-soluble prepolymer in the present invention includes one or more kinds of monomers selected from the monomers represented by the following general formulas (1) to (8), and a monomer capable of cocondensing with these. It is a formaldehyde condensate or a salt thereof, and this water-soluble prepolymer is characterized in that it is made into a resin by a catalyst.

[0010]

Embedded image

(In the formula, R ₁ , R _{3 to} R ₈ ; H or C _{1 to} 9
Alkyl group R ₂ ; H or a hydroxyl group RO ₁ to RO ₄ ; an oxyalkylene group having a carbon number of 2 to 3 n _{1 to} n ₄ ; a positive number of 0 to 100 Z ₁ , Z ₂ ; H or SO ₃ X ₁ X ₁ , X ₂ ; H, monovalent and divalent metals, ammonium, alkylammonium or substituted alkylammonium Y _{1 to} Y ₇ ; H, CH ₂ OH or CH ₂ SO ₃ Z ₃ (Z ₃ is an alkali metal salt). ).

The condensate salt in the present invention is not particularly limited as long as the water solubility of the prepolymer is retained, but preferably, a water-soluble alkali metal salt, an alkaline earth metal salt, and Examples thereof include amine salts.

The weight average molecular weight of the prepolymer in the present invention is not particularly limited as long as it is water-soluble.
The range of 300 to 50,000 is preferable. If the molecular weight is too small, the resinification rate will be slow, while if the molecular weight is too large, the viscosity will be too high, so caution is required in handling.

The amount of the water-soluble prepolymer used in the present invention is 100 parts by weight of the solid content of the asphalt emulsion.
It is preferable to use 0.1 to 75.0 parts by weight. More preferably 0.5 per 100 parts by weight of the solid content of the asphalt emulsion.
~ 50.0 parts by weight. If the amount used is too small, the strength and temperature-sensitive properties as a binder and the function of adhering to the aggregate will be insufficient, while if the amount used is too large, the flexibility as a binder will be insufficient.

The catalyst used in the present invention is not particularly limited, but organic acid esters are preferable from the viewpoint of workability. As the organic acid ester, lactones or organic acid esters derived from a monohydric or polyhydric alcohol having 1 to 10 carbon atoms and an organic carboxylic acid having 1 to 10 carbon atoms are used alone or in a mixture. Particularly preferred are Y-butyrolactone, propionolactone, ε-caprolactone, formic acid ester, ethylene glycol diacetate, ethylene glycol monoacetate, triacetin, propylene carbonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate and the like.

The amount of the catalyst used in the present invention is preferably 1.0 to 50.0 parts by weight, more preferably 3.0 to 25.0 parts by weight, based on 100 parts by weight of the solid content of the prepolymer.
When the amount of catalyst used is small, there is no resinification promoting effect,
On the other hand, if the amount is too large, it is difficult to control the resinification time.

The asphalt composition for room temperature mixing of the present invention is characterized in that the asphalt emulsion and the above-mentioned prepolymer are essential components, and if necessary, a third component such as filler, latex, sand and gravel is added. .

The asphalt emulsion used in the present invention has four types of emulsifiers: anionic emulsion, cationic emulsion, nonionic emulsion and amphoteric emulsion. The surfactant used as an emulsifier in the present invention is an anion. , Cationic, nonionic, and amphoteric may be used, and one or more multi-component system may be used.

Examples of the anionic surfactant include carboxylic acid salts, sulfuric acid ester salts, sulfonic acid salts and phosphoric acid ester salts, and ethylene oxide and propylene oxide adducts thereof are also included.

Examples of the cationic surfactant include alkylamine salts, alkanolamines, quaternary ammonium salts, amine oxides and polyethylene polyamines, and also adducts of ethylene oxide and propylene oxide. Here, in the case of a cationic surfactant that is not a quaternary salt, hydrochloric acid, acetic acid, nitric acid, sulfamic acid, dimethylsulfate or the like is used in the form of each acid salt.

As the nonionic surfactant, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher alkylamine ethylene oxide adduct, fatty acid amide Polyethylene glycol type surfactants such as ethylene oxide adduct, ethylene oxide adduct of oil and fat, polypropylene glycol ethylene oxide adduct, etc., fatty acid ester of glycerol, fatty acid ester of pentaerythritol, fatty acid ester of sorbitol and sorbitan, fatty acid of sucrose Examples include polyhydric alcohol type surfactants such as esters, alkyl ethers of polyhydric alcohols, and fatty acid amides of alkanolamines.

Examples of the amphoteric surfactant include amino acid type and betaine type carboxylic acid salts, sulfuric acid ester salts, sulfonic acid salts, and phosphoric acid esters.

The emulsifier is used in an amount of 0.01 to 10.0% by weight, preferably 0.05 to 5.0% by weight, based on the total amount of water and asphalt.

Asphalt used in the asphalt emulsion includes petroleum straight asphalt, semi-blown asphalt, cutback asphalt, natural asphalt, petroleum tar, pitch, solvent deasphalting asphalt,
Examples include one kind alone or a mixture of two or more kinds selected from heavy oil and the like. In addition, synthetic rubber such as natural rubber, styrene-butadiene copolymer, chloroprene copolymer, and high molecular polymer such as polyethylene and ethylene / vinyl acetate copolymer, petroleum resin, modified asphalt mixed with thermoplastic resin, etc. Can also be used.

The aggregate and filler used in the present invention are not particularly limited, but examples thereof include commonly used crushed stone, crusher run, screenings, crushed stone dust, blast furnace slag, sand and the like. Further, light colored aggregates such as loxobite, artificially fired aggregates, aluminum powder, ceramic grains, colored aggregates, asphalt-coated crushed stones, recycled aggregates from waste asphalt pavement, and the like can also be used. Examples of fillers include fillers of screenings, stone powder, incinerator ash, clay, talc, expansion material, fly ash, various cements (super early strength cement, early strength cement, ordinary cement, mixed cement, etc.), etc. To be done.

The latex used in the present invention is added to impart flexibility to the asphalt composition, and examples thereof include styrene butadiene rubber, isoprene rubber, natural rubber emulsion, acrylic acid emulsion, vinyl acetate emulsion and the like. However, the present invention is not limited to these. The amount of the latex used is preferably 0.1 to 75.0% by weight based on 100 parts by weight of the solid content of the asphalt emulsion.

Further, in the present invention, water-soluble inorganic salts such as ammonium chloride, calcium chloride, aluminum chloride and iron chloride, polyvinyl alcohol, gelatin, polyethylene glycol, methyl cellulose and cationic starch are used in practical use such as purpose and method of use. A water-soluble polymer such as a water-absorbing polymer can be appropriately selected and used in combination.

[0028]

INDUSTRIAL APPLICABILITY As described above in detail, the present invention remarkably improves the strength of an asphalt composition by adding a water-soluble prepolymer to the asphalt emulsion, the reaction of which gradually progresses in an aqueous solution to form a resin. In addition, the rate of resinification can be freely controlled by the action of the catalyst. Therefore, the additive for asphalt emulsion and the asphalt composition for room temperature mixing of the present invention can be effectively used for various applications such as road paving, railroad lines, waterproofing agents and adhesives.

[0029]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Production Example of Water-Soluble Prepolymer Various monomers were added to an aqueous alkali solution, and stirred and dissolved. An aqueous formaldehyde solution was gradually added to this solution to synthesize various prepolymers shown below. The molecular weight of the prepolymer was adjusted by adjusting the reaction time. still,
The molecular weight of the prepolymer was determined as a weight average molecular weight by GPC (gel permeation chromatography). Adjust the sample to the specified concentration and then use the guard column TSK HXL (6.5 mm diameter x 4 cm) (manufactured by Tosoh Corporation)
One and TSK G3000HXL (7.8mm diameter x 30cm) 1
And one TSK G2500HXL (7.8 mm diameter x 30 cm) were connected in series and measured. In addition, polystyrene (manufactured by Tosoh Corporation) was used as a standard sample.

<Type of water-soluble prepolymer>A-1; formaldehyde condensate of phenol A-2; formaldehyde condensate of bisphenol A A-3; formaldehyde condensate of melamine A-4; formaldehyde condensate of furfuryl alcohol A-5: Formaldehyde condensate of phenol / sulfanilic acid A-6: Formaldehyde condensate of phenol / urea.

Example 1 Asphalt uses petroleum straight asphalt having a penetration of 80 to 100, and 1 is used for the total amount of water and asphalt.
An asphalt emulsion having an asphalt content of 60 wt% was prepared using wt% sodium oleate. After 24 hours, 10 parts by weight of the naturally cooled asphalt emulsion was added to 100 parts by weight of the aggregate, 10% by weight of various prepolymers shown in Table 1 was added to the solid content of the asphalt emulsion, and ethylene glycol diacetate was added to the prepolymer. For polymer solids
Various tests shown below were carried out by adding 10% by weight. Table 1 shows the test results.

<Strength Test> The strength of the asphalt composition is the Marshall stability test method (60 ° C.) described in the Pavement Test Manual (published by the Japan Road Association) in order to evaluate the strength of the pavement using the asphalt emulsion. Water immersion for 30 minutes). The specimen for Marshall stability test was prepared by the following method. The asphalt emulsion composition was prepared by mixing a crushed stone No. 6 and a crushed stone No. 7 in a bag mill mixer with 100 parts by weight of a fine-grained aggregate containing the asphalt emulsion, the asphalt emulsion additive of the present invention, and other additives. A predetermined amount was added and mixed for 20 seconds to prepare. The aggregate temperature was 20 ° C. After 10 minutes, the mixture was put into a mold, and a specimen for Marshall stability test was prepared on both sides at room temperature 50 times on one side, and allowed to cure for 24 hours in a thermostatic chamber at 20 ° C.

<Durability Test> In order to evaluate the durability of a pavement using an asphalt emulsion, a wheel tracking test (temperature 60 ° C., ground pressure 6.4 kgf) described in the Pavement Test Manual (published by the Japan Road Association). / cm ² ) was performed. A wheel tracking test specimen was prepared by the following method. Put the asphalt emulsion composition prepared for the strength test in a compacting mold and compact with a roller compactor,
A wheel-tracking test specimen was prepared and cured in a constant temperature room at 20 ° C for 24 hours.

<Evaluation of Water Resistance Performance> An adhesion test was carried out in order to evaluate the water resistance performance of the asphalt coated on the surface of the aggregate with the asphalt emulsion, and thus the peeling prevention performance.
The test method is as follows. Immerse 5 to 13 mm of dry aggregate in water (20 ° C.) for 1 minute, and immediately after taking it out, soak for 1 minute in the mixture of the asphalt emulsion and the asphalt emulsion additive of the present invention. Arrange the aggregate on a glass plate,
After curing this for 24 hours in a temperature-controlled room at 20 ℃,
Soak in warm water at ℃ for 30 minutes. After 30 minutes, the rate at which the surface of the aggregate was covered with the asphalt film was judged with the naked eye and displayed as an adhesion area (%). However, the number of aggregates used in one test is 10, and the average value is shown.

[0036]

[Table 1]

In the comparative example, sufficient strength was not obtained even after curing for 24 hours in a thermostatic chamber at 20 ° C., and the sample was broken when taken out from the compacting mold. Therefore, the test could not be conducted.

From the results shown in Table 1, the addition of the water-soluble prepolymer of the present invention may improve the strength, durability and water resistance of the asphalt emulsion composition.

Example 2 An asphalt emulsion composition was prepared and evaluated according to the conditions of Example 1 except that various catalysts shown in Table 2 were used. All the prepolymers including the comparative examples were A-
1 (molecular weight 3000) was used. Table 2 shows the results of the stability test with respect to the curing time.

[0040]

[Table 2]

* EGDA; ethylene glycol diacetate GE; formate ester PC; propylene carbonate Y-BR; Y-butyrolactone TA; triacetin.

From the results shown in Table 2, by combining the water-soluble prepolymer with an organic acid ester as a curing accelerator, the decomposition and coalescence of the asphalt emulsion is promoted, and the resinification rate of the asphalt emulsion composition is controlled. It is confirmed that things can be done.

Example 3 Prepolymers against solids of asphalt emulsion in Table 3
The asphalt emulsion composition was prepared and evaluated according to the conditions of Example 1 except that the ratio was used. As the prepolymer, A-1 (molecular weight 3000) was used. Table 3 shows the test results of various tests.

[0044]

[Table 3]

From the results shown in Table 3, when the amount of the prepolymer added is small, the flexibility tends to be particularly excellent.
It is confirmed that when the amount is large, the strength and durability are particularly excellent.

Example 4 Example 1 except that various auxiliary additives shown in Table 4 were used in the ratio shown in Table 4 with respect to the solid content of the asphalt emulsion.
The asphalt emulsion composition was prepared and evaluated according to the conditions described in 1. The prepolymer was not added in Comparative Examples, and all A-1 (molecular weight 3000) was used in the products of the present invention. The test results of various tests are shown in Table 4.

[0047]

[Table 4]

It is confirmed that sufficient strength is obtained also by adding the auxiliary additive. Although the purpose of use is different, latex is often used for the purpose of imparting flexibility, and the flow value is also improved in the examples, while cement and the like are used for strength improvement purposes together with adjustment of strength development time. Also, the tendency is confirmed in the examples.

Claims (6)

[Claims] 1. An additive for an asphalt emulsion, which comprises a water-soluble prepolymer as an essential component, which undergoes a reaction gradually in an aqueous solution to form a resin. 2. A water-soluble prepolymer, one or more monomers selected from the monomers represented by the following general formulas (1) to (8), and formaldehyde condensation with a monomer capable of co-condensing with these monomers. The asphalt emulsion additive according to claim 1, which is a substance or a salt thereof. Embedded image (In the formula, R ₁ and R _{3 to} R ₈ ; H or an alkyl group R ₂ having 1 to 9 carbon atoms; H or a hydroxyl group RO ₁ to RO _{4, and an} oxyalkylene group n _{1 to} n ₄ having 2 to 3 carbon atoms; 0 to 100 positive numbers Z ₁ , Z ₂ ; H or SO ₃ X ₁ X ₁ , X ₂ ; H, monovalent and divalent metals, ammonium, alkylammonium or substituted alkylammonium Y _{1 to} Y ₇ ; H, CH ₂ OH or CH ₂ SO ₃ Z ₃ (Z ₃ is an alkali metal salt) 3. The weight average molecular weight of the water-soluble prepolymer is
The additive for an asphalt emulsion according to claim 1 or 2, which is in the range of 300 to 50,000. 4. A resin composition of a water-soluble prepolymer progresses with a catalyst, according to any one of claims 1 to 3.
Additive for asphalt emulsion according to the item. 5. An asphalt composition for room temperature mixing, comprising an asphalt emulsion and the water-soluble prepolymer according to any one of claims 1 to 4 as an essential component. 6. An asphalt emulsion, the water-soluble prepolymer according to any one of claims 1 to 4, and a filler,
An asphalt composition for room temperature mixing, which comprises one or more selected from the group consisting of latex, sand and gravel as an essential component.