JP3464863B2 - Asphalt emulsion - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-in-water type asphalt emulsion, and more specifically, asphalt emulsion properties such as emulsion stability, miscibility with aggregates, decomposition time control, adhesion, strength, high durability, Further, the present invention relates to an asphalt emulsion excellent in peeling prevention effect and the like.

[0002]

Bituminous materials such as asphalt obtained from petroleum have been widely used for paving materials, waterproof / adhesive materials, railroad tracks, etc. since ancient times, but they are very sticky. It is a substance with a high content and its workability is extremely poor as it is. Therefore, improve the fluidity of asphalt by heating the asphalt when performing the desired work (heating and melting method), adding an appropriate emulsifier and water to form an emulsion, and dissolving it in an appropriate solvent. Is being done.

Among these methods, an aqueous asphalt emulsion prepared by emulsion is generally called "asphalt emulsion". Asphalt emulsion is prepared by appropriately adding aggregates, fillers and other components. The composition is formed and is used, for example, for forming a pavement. At that time, the asphalt is hardened by evaporating and removing the aqueous component and causing so-called emulsion destruction.

There are three types of asphalt emulsions, anionic emulsions, cationic emulsions and nonionic emulsions, depending on the type of emulsifier (surfactant) used, and these emulsions are rapidly degradable for direct application to the working surface. The emulsion can be roughly classified into a slow-degrading emulsion that is used by mixing with the aggregate.

In any case, since the asphalt regenerated by breaking the emulsion acts as a binder between the aggregates, the function of adhering to the aggregates is extremely important. However, although the anionic emulsion and the nonionic emulsion have the advantage that they are well mixed with the aggregate, they have the major drawback of poor adhesion to the aggregate. On the other hand, the cationic emulsion imparts an adhesive function by exerting an electric attraction between the asphalt-dispersed particles and the aggregate, but it cannot be said to be sufficient in practical use, and its improvement measures are required. .

Further, it is important that the slow-degrading emulsion used by mixing with the aggregate has good mechanical stability by forced stirring and mixing, and that it does not decompose during transportation, spreading, rolling, etc. However, it is necessary to satisfy the following conditions: after the pavement, it decomposes to some extent quickly and has excellent adhesiveness, and that these properties are not affected by the type of aggregate, the temperature during construction, etc. To avoid this, use a large amount of emulsifier,
Further, a method of adding a water-soluble organic polymer such as polyvinyl alcohol, gelatin, methyl cellulose, polyacrylamide, guar gum or the like as a protective colloid has been widely considered. However, while the asphalt emulsion is stabilized, it improves the properties of the aggregate-asphalt interface,
It is not possible to obtain the effect of essentially improving the adhesion with the aggregate.

In addition, asphalt emulsion aggregate mixing property,
Various methods have heretofore been devised for improving the adhesion performance. For example, according to USP3871893 (1975), aminated lignin, alkylimidazoline-based and nonionic emulsifier combination system, further USP3979323 (1976) alkylimidazoline-based fatty acid salt, and also JP-A-7-118538 discloses a nonionic system. Improvements have been made with emulsifiers. However, although the aggregate mixing property is improved, the adhesion and peeling resistance due to the intervention of water are still insufficient. Further, in JP-A-57-42763, saturated fatty acids are used, and in USP3867162 (1975), tall oil fatty acids are considered to be used, but in this case, it is used in a compounding system in which cement showing alkalinity or iron ore is mixed. It is impossible. On the other hand, JP-A-63-17960 shows that the incorporation of tannic acid or a tannin compound in the asphalt emulsion can improve the mixing property with the aggregate, the decomposition time control, the adhesion property, and the peeling prevention effect. However, under recent circumstances where the quality of road asphalt and aggregate has deteriorated, it cannot be said that the effect is sufficient, and further modification of the asphalt emulsion is strongly desired,
It has become a big issue for the industry.

[0008]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that by incorporating polyphenols having a specific molecular weight distribution into an asphalt emulsion, the emulsion stability and the aggregate can be improved. It was found that an asphalt emulsion having dramatically improved mixing properties, adhesiveness to aggregates, strength development of composites, high durability, and peeling resistance was obtained,
The present invention has been completed.

That is, the present invention relates to column chromatography.
A polyphenol obtained by fractionation by
In the molecular weight distribution by gel permeation chromatography (GPC) measurement after acetylation of the polyphenols under specific conditions, the absolute area percentage of the components having a weight average molecular weight of 2800 or more on the chromatograph is 10% or less. > Ah is, chromatographed on a weight average molecular weight of 1,500 to 2,600
The absolute area percentage of the components is related to bitumen emulsion, characterized by containing der Ru polyphenols than 90%.

More specifically, the present invention relates to asphalt 40.
To 80 parts by weight and 60 to 20 parts by weight of water for a total of 100 parts by weight, the present invention relates to an asphalt emulsion characterized by containing 0.01 to 10.0 parts by weight of a surfactant and 0.01 to 10.0 parts by weight of the polyphenols. Is.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The polyphenols used in the present invention include those having two or more hydroxyl groups in the benzene ring, or phenols and their oxidatively polymerized substances. Specifically, quintet, gallic, smack,
Hydrolyzable tannins such as cod, baronia, chestnut, mirobaran, oak (kashiwa), dividibi, argalovia, lychetan, cascalote, gambia, quebracho, mimosa, acacia, mangrove, hemlock, spruce, burmacatchi, oak bark, oyster Examples thereof include condensed tannins such as astringent astringents, digipto, Chinese tannins, Turkish tannins, hamamelitannin, quebric acid, ellagic acid tannin, and purified tannic acid and lignin of these.

In the present invention, a compound having a desired molecular weight distribution can be obtained by separating these polyphenols by column chromatography. These are used alone or as a mixture.

The method for acetylating these compounds and measuring the molecular weight (distribution) by GPC is as follows.

[Acetylation Method] Polymer Analysis Handbook
(P.783 to 784, 1995, Kinokuniya Bookstore) acetylate the sample. That is, 2 g of a sufficiently dried sample was placed in a 50 ml Erlenmeyer flask with a stopper, and the pyridine was cooled with ice.
Add 10 ml of acetic anhydride and dissolve. When the fever disappears, close the cap tightly and let stand at room temperature (20 ℃) in the dark for 12 hours. Then, this is poured into a 200 ml beaker containing 100 ml of ice water to precipitate an acetylated product. This is filtered with a filter paper, washed with ice water, air-dried with nitrogen gas, and dried under reduced pressure at room temperature to obtain an acetylated product.

[GPC measurement conditions] Sample size: 0.5%, 100 ml column: G4000HXL + G2000HXL (manufactured by Tosoh) Eluent: 50 mM CH ₃ COOH / THF Flow rate: 1.0 ml / min Column temperature: 40 ° C Detector: R1 Standard substance: Polystyrene .

In the molecular weight distribution of polyphenols after acetylation, the absolute area percentage of components having a weight average molecular weight of 2800 or more on the chromatograph is 10% or less, and further 5% from the viewpoint of adhesion to aggregates. It is preferably below 1%, in particular. In addition, in the molecular weight distribution after acetylation, the weight average molecular weight on the chromatograph was 1500 to 2600.
The absolute percentage of the component is 90% or more, and particularly preferably 95% or more. Furthermore, in the molecular weight distribution after acetylation, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 1.4.
It is preferably 1.3 or less, more preferably 1.2 or less.

Examples of the asphalt used in the present invention include one or a mixture of two or more of petroleum straight asphalt, semi-blown asphalt, cutback asphalt, natural asphalt and the like. Further, synthetic rubber such as natural rubber, styrene-butadiene copolymer, styrene-isoprene copolymer, chloroprene copolymer, high molecular polymer such as polyethylene, ethylene-vinyl acetate copolymer, petroleum resin, thermoplastic resin, etc. Modified asphalt with addition of can also be used. Other than that, for example, inorganic fillers and organic fillers such as calcium carbonate, slaked lime, cement, activated carbon, petroleum-based softeners, plant-based softeners, various plasticizers,
If necessary, sulfur or the like can be added.

The surfactant component used in the present invention is
Any surfactant selected from cationic type, nonionic type, anionic type and amphoteric type may be used, and two or more kinds of multi-component type may be used. Here, in the case of a cationic emulsifier other than the quaternary salt type, it is used in the form of an acid salt such as hydrochloric acid, acetic acid, nitric acid or sulfamic acid. As the surfactant, one having an HLB of 10 or more is desirable, and the amount used is 0.01 to 10.0 parts by weight, preferably 0.
The appropriate amount is 05 to 3.0 parts by weight.

In the present invention, the polyphenols having a weight-average molecular weight of 2800 or more and an absolute area percentage of 10% or less in the molecular weight distribution by GPC measurement after acetylation of the polyphenols are used as an asphalt emulsion. 0.01 to 10.0 parts by weight, preferably
Use 0.1 to 3.0 parts by weight.

In addition, in practical use such as purpose of use and construction method, water-soluble inorganic salts such as ammonium chloride, calcium chloride, aluminum chloride and iron chloride, and water-soluble polymers such as polyvinyl alcohol, gelatin, hydroxyethyl cellulose, methyl cellulose and cationic starch. , Or water-soluble natural rubber, naphthalene sulfonic acid formaldehyde condensate, melamine sulfonic acid formaldehyde condensate, phenol sulfonic acid formaldehyde condensate, polycarboxylic acid copolymer and water-soluble salts thereof, and also crout obtained from softwood or hardwood Lignin, anionic polymer dispersants such as sulfonated lignin and water-soluble salts thereof, or gluconic acid, glucoheptonic acid, arabonic acid,
Oxycarboxylic acids such as malic acid, citric acid and water-soluble salts thereof, or monosaccharides such as glucose, fructose, galactose, saccharose and isomerized sugar, oligosaccharides such as dextrin, or sugars such as polysaccharides such as dextran. , Or molasses containing them, sugar alcohols such as sorbitol, epoxy compounds such as epichlorohydrin, etc. can be appropriately selected and used together (in some cases, reacted).

[0021]

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

Examples 1 to 6, Reference Examples 1 and 2 and Comparative Example 1 [Preparation of asphalt composition] Asphalt having a penetration of 80 to 100 was heated and melted at 145 ° C. On the other hand, after dissolving the surfactant shown in Table 2 and 0.15 part by weight of calcium chloride in warm water at 45 ° C., the polyphenols prepared by fractionation by column chromatography shown in Table 1 were added and dissolved. This 45 ℃ emulsified aqueous solution 40
An emulsion was prepared by simultaneously passing parts by weight and 60 parts by weight of the above-mentioned molten asphalt at 145 ° C. through a Haller homogenizer.
However, when the amine-based surfactant was used, hydrochloric acid was used and the pH of the emulsified aqueous solution was adjusted to 2. The following tests were conducted using the obtained emulsified aqueous solution. The results are summarized in Table 2. For comparison, an emulsion to which no polyphenols were added (Comparative Example 2) and an emulsion to which unfractionated polyphenols (Acacia) were added (Comparative Example 1) were prepared and the same test was conducted.

<Test Method> (1) Emulsion Storage Stability According to JIS K 2208-1980, ◯ indicates that the standard was passed, and x indicates that the standard was not passed.

(2) Adhesion with crushed stones Dry crushed stones of 5 to 13 mm are immersed in water for 1 minute, and immediately after being taken out, they are immersed in emulsion for 1 minute. Then, it is taken out from the emulsion, crushed stones are lined up on a glass plate, aged at room temperature for 24 hours, and then immersed in warm water at 80 ° C. for 1 hour. After 1 hour, the ratio of the area where the surface of the crushed stone is covered with the asphalt film is visually determined, and the adhesion area (%) is obtained. However, the number of crushed stones used in one test was 10, and the type of crushed stone was limestone. The judgment of the result was evaluated by the following x, Δ, ◯, and ⊚. ×: Asphalt adhesion area (%) is less than 50% △: Asphalt adhesion area (%) is 50% or more and less than 70% ○: Asphalt adhesion area (%) is 70% or more and less than 90% ◎: Asphalt adhesion area (%) Is over 90%.

(3) Aggregate mixability To 2200 g of dry aggregate having a composition suitable for the particle size distribution of the dense particle size mixture described in the road paving summary, 60 g of added water is added and mixed, and 240 g of asphalt emulsion is added to the asphalt. The compatibility of the emulsion with the aggregate was tested. The test temperature was 25 ° C., and the mixer used was an asphalt mixture preparation (5 liters) manufactured by World Test Co., Ltd. and kneaded for 2 minutes. The evaluation was evaluated by the following x, Δ, ◯, and ⊚. ×: Emulsion was decomposed during mixing Δ: Evenly mixed, but immediately decomposed ○: Evenly mixed, workability was short ◎: Evenly mixed, good workability and sufficient working time is there.

(4) Crush strength To 1140 g of dry aggregate having a composition suitable for the particle size distribution of the dense particle size mixture described in the road pavement summary, 24 g of added water was added and mixed, and then 60 g of asphalt emulsion was added and mixed. . This was placed in a mold for Marshall stability test, compacted 75 times, and then inverted and compacted 75 times. The sample was taken out of the mold, cured at 60 ° C. for 3 days, and then immersed in warm water at 60 ° C. for 24 hours. After cooling the specimen to 20 ° C., the rupture strength was measured with a load measuring device.

[0027]

[Table 1]

[0028]

[Table 2]

[0029]

As described above in detail, according to the present invention,
By preparing an asphalt emulsion by appropriately selecting asphalt, polyphenols having a specific molecular weight distribution, and a surfactant, emulsion storage stability, aggregate mixability,
An asphalt emulsion was obtained which satisfied all of the various market demands such as aggregate adhesion, strength, high durability, and peel resistance. Therefore, such an asphalt emulsion can be effectively used for applications such as road paving, railroad tracks, cement asphalt mortar, anticorrosion, rustproofing, waterproofing, adhesives, and agricultural land improvement materials. it can.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Sayuri Tamaki 1334 Minato Minato, Wakayama City, Wakayama Prefecture Research Institute (56) Reference JP-A-63-17960 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 95/00 C08K 5/13

Claims (2)

(57) [Claims] 1. A surfactant 0.01 to 1 to 100 parts by weight of a total of 40 to 80 parts by weight of asphalt and 60 to 20 parts by weight of water.
It contains 0.0 parts by weight and 0.01 to 10.0 parts by weight of polyphenols, and the polyphenols are subjected to column chromatography.
Was obtained by fractionation according to the following procedure, and in the molecular weight distribution by gel permeation chromatography measurement after acetylation under the following conditions, on the chromatograph,
Absolute area percentage of components with weight average molecular weight of 2800 or more is 10
% Or less, and the weight average molecular weight on the chromatograph is 15
An asphalt emulsion characterized in that the absolute area percentage of the components of 00 to 2600 is 90% or more. [Acetylation method] A sample is acetylated according to the Polymer Analysis Handbook (P.783 to 784, 1995, Kinokuniya Bookstore). That is, take 2 g of a sufficiently dried sample in a 50 ml Erlenmeyer flask with a stopper,
While cooling with ice, 10 ml of pyridine and 10 ml of acetic anhydride are added and dissolved. When the fever disappears, close the cap tightly at room temperature (20
℃), leave it in the dark for 12 hours. Then add this to ice water 100
Pour into a 200 ml beaker containing ml to precipitate the acetylated product. This is filtered with a filter paper, washed with ice water, air-dried with nitrogen gas, and dried under reduced pressure at room temperature to obtain an acetylated product. [Gel permeation chromatography measurement conditions] Sample size: 0.5%, 100 ml Column: G4000HXL + G2000HXL (manufactured by Tosoh) Eluent: 50 mM CH ₃ COOH / THF Flow rate: 1.0 ml / min Column temperature: 40 ° C Detector: R1 Standard substance: polystyrene 2. The weight average molecular weight (Mw) and the number average molecular weight (Mw) in the molecular weight distribution of polyphenols after acetylation.
The ratio of n) (Mw / Mn) is 1.4 or less is claim 1 Symbol placement of bitumen emulsion.