JPH07316437A - Asphalt improver and method for improving asphalt - Google Patents

Abstract

PURPOSE:To obtain an improver which has an excellent balance among cohesive characteristics, exhibits high toughness and tenacity for an aggregate, and is suitable for improving asphalt for road pavement requiring resistances to flow abrasion and crack CONSTITUTION:An asphalt improver is prepd. by mixing asphaltite pref. in an amt. of 50-65wt.%, a tackifier pref. in an amt. of 25-35wt.%, and a polymer dispersion pref. in an amt. of 10-25wt.%. A method for improving asphalt is provided wherein asphalt is compounded and kneaded with the improver in such an amt. that the amts. of the asphaltite, tackifier, and polymer dispersion in the resulting improved asphalt are 2.5-13 pts.wt., 1.25-7 pts.wt., and 0.5-5 pts.wt., respectively, based on 100 pts.wt. asphalt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an asphalt modifier and a method for modifying the asphalt, and particularly to fluid resistance, abrasion resistance, crack resistance, etc., such as road pavement with heavy traffic of vehicles. The present invention relates to a novel modifier and an asphalt modifying method for providing a modified asphalt suitable for the demanding field.

[0002]

2. Description of the Related Art A composition obtained by mixing asphalt with aggregates such as stones and sand is relatively stable and has excellent wear characteristics.
It has the characteristics that it does not require a long curing period during construction and is inexpensive, so it is widely used as a paving material for roads and the like. However, asphalt is inferior in physical properties such as toughness and tenacity, and has the unfavorable temperature-sensitive property that it becomes soft or hard depending on the change in temperature as the biggest drawback. Therefore, for the purpose of improving such defects, polyethylene, ethylene-ethyl acrylate copolymer and other resins, styrene-
It has been attempted to modify by adding synthetic rubber such as butadiene random copolymer rubber, natural rubber or natural asphalt which is a hardened asphalt (Japanese Patent Laid-Open Nos. 1-254768 and 2-251570, No. 2-292368).

As a method for producing these modified asphalt, a premix type in which asphalt and resin, synthetic rubber, natural rubber or natural asphalt are melt-mixed at a factory in advance and supplied by a lorry, and asphalt and bone in an asphalt plant are used. There is a plant mix type in which a resin, a synthetic rubber, a natural rubber or a natural asphalt is added as a solid, a powder, a granular material or an emulsion directly and mixed in a mixer at the time of heating and mixing with a material.

In the former modified asphalt produced by the premix type, a resin, a synthetic rubber, a natural rubber or a modifier of natural asphalt is added to improve the temperature sensitivity of the asphalt. The melt viscosity of the asphalt produced becomes extremely high, and if it is stored in the molten state, it will lack stability and often cause gelation, and the asphalt and the modifier will separate, causing problems in terms of quality. I often do it.

Further, since it cannot be stored for a long period of time, it has a drawback that it is uneasy to transfer or supply it to a remote place and the supply range is restricted. The modified asphalt produced by the latter plant mix type is a modified asphalt obtained by adding a resin, synthetic rubber, natural rubber or natural asphalt as a modifier when the asphalt and the aggregate are heated and mixed in the asphalt plant. It is said that it has a merit that it does not need to be stored because it is made of a mixture, unlike the premix type, and that deterioration due to heat history can be prevented.

However, the modifier resin, synthetic rubber, natural rubber and the like used therein are solid, powder, granular material or emulsion in a mixer of an asphalt plant together with asphalt and aggregate for a short time. It is difficult to obtain a homogeneous modified asphalt mixture because it is difficult to achieve complete melting and uniform dispersion due to its high melting point. . Therefore, compared with the case of mixing ordinary petroleum asphalt (Japan Road Association standard: 60/80 or 80/100) in an asphalt plant, the production is carried out at a high mixing temperature and a long mixing time. For this,
It is said that the modified asphalt is susceptible to thermal deterioration, and the production capacity of the modified asphalt mixture per hour is reduced.

On the other hand, in the method of adding solid, powder, or granular natural asphalt as a modifier, the generation of dust is accompanied and the deterioration of the working environment is always a problem. Furthermore, since natural asphalt has properties equivalent to those obtained by simply curing asphalt, even if added alone to asphalt, the flowability at high temperatures is improved, and the flexibility at low temperatures is low. The improvement of the tenacity and the tenacity was insufficient, and the modified asphalt had a defect in quality.

[0008]

DISCLOSURE OF THE INVENTION The present invention overcomes the drawbacks of the conventional modified asphalt and has an excellent balance of physical properties such as temperature sensitivity, toughness and tenacity and workability, and particularly plant mix. It is an object of the present invention to provide an asphalt modifier and a method for modifying an asphalt that provides a type of modified asphalt.

[0009]

Means for Solving the Problems In order to solve the above problems, the inventors of the present invention have earnestly studied and, as a result, have obtained a wet powdery form obtained by previously mixing natural asphaltite, a tackifier and a polymer dispersion liquid. In order to complete the present invention, it was found that the composition of 1 is suitable as a modifier for giving a plant mix type modified asphalt having an excellent balance of physical properties such as temperature sensitivity, toughness and tenacity and workability. I arrived.

That is, according to the present invention, 1) an asphalt modifier, which is characterized by mixing asphaltite, a tackifier and a polymer dispersion, and 2) the mixing ratio of each component is asphaltite 50. ~ 65
% By weight, tackifier 25-35% by weight, polymer dispersion 1
0 to 25% by weight, the asphalt modifier according to 1 above, 3) The asphaltite has a softening point of 130 to 200 ° C., and a fixed carbon of 10 to 20%. 4) Asphalt modifier, 4) The tackifier has a viscosity of 20 to 80 cSt / 100 ° C,
The total amount of aromatic and naphthene components is 45% by weight or more, and the flash point is 2.
The asphalt modifier according to 1 or 2 above, which is a solvent-extracted oil at 20 ° C. or higher,

5) A vinyl polymer polymer dispersion obtained by emulsion homopolymerization or emulsion copolymerization of a monomer selected from vinyl acetate, acrylic, vinylidene chloride and vinyl chloride monomers. 3. The asphalt modifier according to 1 or 2 above, which is a synthetic rubber-based polymer dispersion obtained by emulsion homopolymerization or emulsion copolymerization of butadiene or a derivative thereof, and has a viscosity of 100 to 500 cps. 6) The asphalt modifier for paving according to any one of 1 to 5 above, wherein the asphalt is asphalt for paving. 7) A method for modifying asphalt, characterized in that a modifier, which comprises asphaltite, a tackifier, and a polymer dispersion, is blended in asphalt and kneaded.

8) 50-65% by weight of asphaltite,
Tackifier 25-35% by weight and polymer dispersion 10-2
A modifier composed of 5% by weight is used, and the blending ratio of each of the above components to 100 parts by weight of asphalt is asphaltite 2.
9. A method for modifying asphalt according to 7 above, which comprises blending 5 to 13 parts by weight, 1.25 to 7 parts by weight of tackifier and 0.5 to 5 parts by weight of the polymer dispersion, and kneading. 9. The method for modifying asphalt according to 7 or 8 above, which comprises blending a small amount of a modifier into a bag made of a thermoplastic resin, and 10) the asphalt is asphalt for paving.
A method for modifying the asphalt for pavement according to any one of 1 to 9 is provided.

The asphalt modifier of the present invention can be obtained by mixing asphaltite as a main raw material with a tackifier and a polymer dispersion at room temperature to form a wet powder. Of the raw materials for the asphalt modifier of the present invention, the main raw material is asphaltite, which is a natural product of asphalt that is oxidatively polymerized and hardened, and is known as Gilsonite, glan pitch, grahamite, or the like. Can be used. Among them, Gilsonite does not contain silt, clay, salt, etc. at all, melts 99.8% in carbon disulfide almost completely, and is obtained in a substantially pure form in nature, so there is little variation in quality. Particularly preferred as a raw material for the asphalt modifying material of the invention.

In the modifier of the present invention, a tackifier is blended for the purpose of preventing the asphaltite from scattering, improving the solubility and adjusting the viscosity of the modified asphalt to be high. The tackifier used in the present invention is an oily substance rich in aromatic and naphthene components obtained by solvent extraction in the process of producing a lubricating oil from crude oil, and generally has a boiling point (under atmospheric pressure) of 350 ° C. or higher, Viscosity 5-100 cSt / 100 ° C.,
Preferably, 20 cSt to 80 cSt / 100 ° C., penetration (JIS K 2207) 1000 or more, softening point (JIS K 2207) 20 ° C.
The following, especially when the total of aromatic and naphthene contents is 4
It preferably accounts for 5% by weight or more and has a flash point of 220 ° C. or more. It should be noted that the aromatic and naphthene contents may be contained in the above-mentioned ranges as measured by a known ring analysis method (nbM method).

In the modifier of the present invention, a polymer dispersion is blended for the purpose of improving the flow resistance of the modified asphalt and improving the wear resistance and crack resistance at low temperatures. The polymer dispersion used in the present invention, vinyl acetate-based, acrylic-based, vinyl polymer-based polymer dispersion obtained by emulsion homopolymerization or emulsion copolymerization of vinyl monomers such as vinylidene chloride and vinyl chloride. Examples thereof include synthetic rubber-based polymer dispersions obtained by emulsion homopolymerization or emulsion copolymerization of butadiene or a derivative thereof. Among these, styrene-butadiene copolymer rubber latex, methyl methacrylate-butadiene copolymer rubber latex, acrylonitrile-butadiene copolymer rubber latex, and chloroprene homopolymer rubber latex, synthetic rubber latex such as butadiene homopolymer rubber latex. Is preferred. In particular, a synthetic rubber latex which is an emulsion polymer having a viscosity of 100 to 500 cps is preferable. In the present invention, one kind or a mixture of two or more kinds may be used.

The asphalt modifier of the present invention is the above-mentioned 3
It is made by mixing the components. The blending ratio is asphaltite 50 to 65% by weight, preferably 53 to 53% by weight, tackifier 25 to 35% by weight, preferably 28 to 32% by weight, and polymer dispersion 10 to 25%.
%, Preferably 13 to 22% by weight. When the blending ratio of asphaltite is less than 50% by weight, the blending ratio of the tackifier and the polymer dispersion becomes high, and the temperature-sensitive modification such as the flow resistance of the modified asphalt becomes insufficient, resulting in 65% by weight. If it exceeds 0.1%, the blending ratio of the tackifier and the polymer dispersion becomes low, and the effect of modifying the crack resistance and abrasion resistance of the modified asphalt becomes insufficient. When the blending ratio of the tackifier is less than 25% by weight, the blending ratio of alfaltitite and the polymer dispersion becomes high,
The melt viscosity of the modified asphalt becomes high, resulting in deterioration of workability and dispersibility. If it exceeds 35% by weight, the blending ratio of the asphaltite and the polymer dispersion becomes low, and the temperature-sensitive modification such as fluidity resistance of the modified asphalt becomes insufficient. If the blending ratio of the polymer dispersion liquid is less than 10% by weight, the tenacity of the modified asphalt is not sufficient and the effect of modifying crack resistance is small, and if it exceeds 25% by weight, the melt viscosity of the modified asphalt becomes high and work It is accompanied by a decrease in sex and a decrease in dispersibility.

The asphalt modifier of the present invention is the above-mentioned 3
It can be easily produced by mixing the components by an appropriate method. Specific examples of the production method include (1) kneading the lumpy asphaltite and tackifier, and the polymer dispersion at room temperature with a Banbury mixer, a kneader, etc. Method for obtaining modifier, (2) Wet powder modifier obtained by mixing powdered asphaltite and tackifier, which have been ground to about 0.3 to 2.5 mm in advance, and a polymer dispersion with a mixer at room temperature. Is a method of obtaining

As the asphalt to be modified in the present invention, there are petroleum-based asphalts such as straight asphalt / PDA (propane debris) asphalt and semi-blown asphalt having a penetration of 20 to 150 at 25 ° C.
The range of 10 is preferable, and the range of 40 to 100 is particularly preferable. Further, the crude oil for producing asphalt is not particularly limited, and any of paraffin-based, naphthene-based, and mixed-base crude oil used in the production of ordinary petroleum products can be used. Further, the ratio of the wet-powder-like asphalt modifier to be added to the asphalt and the aggregate such as the mineral matter and sand when the mixture is produced by the plant mix is 1% asphalt.
5 to 20 parts by weight, especially 8 to 17 parts by weight is desirable with respect to 00 parts by weight. The basic composition of the asphalt modifier of the present invention is the ratio of the asphalt and the asphalt modifier, and when the asphalt modifier is less than 5 parts by weight, the improvement of temperature sensitivity such as fluidity resistance is improved. It is not sufficient and the modification effect is small. On the other hand, when it exceeds 20 parts by weight, the physical properties are good, but the melt viscosity of the modified asphalt becomes high, and workability and dispersibility are deteriorated.

The asphalt modifier of the present invention has various properties such as temperature-sensitive property (flow resistance), abrasion resistance, crack resistance, viscosity and penetration depending on the compounding ratio. Therefore, it can be applied to many applications such as road pavement, waterproofing material, vibration damping material, but the common effect is to significantly improve the flow resistance, wear resistance, crack resistance, etc. of asphalt. can give. The asphalt modifier of the present invention can be filled in a polyethylene bag or the like with a small amount of 1 to 3 kg, and when the asphalt plant mixes the asphalt and the aggregate to produce a modified asphalt mixture, a small amount of filling The entire polyethylene bag or the like can be directly added.

[0020]

The asphalt modifier obtained by the present invention retains the original characteristics of asphaltite, and has a high balance of cohesive strength properties in combination with a tackifier and a polymer dispersion. However, by exhibiting great toughness and tenacity with respect to aggregates, it is excellent as a modifier for asphalt for pavement and the like, which requires fluidity resistance, wear resistance, and crack resistance. Further, as a plant mix type asphalt modifier, it can be dissolved at a lower mixing temperature, can be uniformly dispersed in aggregate and asphalt, and a homogeneous modified asphalt mixture can be obtained.

Further, it can be put into a plant in a wet powder form with a small amount filled in a polyethylene bag or the like, and since it is easy to handle, the working efficiency can be improved and the working environment can be prevented from deteriorating. Since the asphalt modifier of the present invention has the above-mentioned characteristics, it can be suitably used as a plant mix type asphalt modifier of road asphalt.

[0022]

EXAMPLES The present invention will be described below based on examples.
The present invention is not limited to these. [Raw material raw material and asphalt] The raw material and asphalt of the modifier used in the examples and comparative examples are as follows.

1) Asphaltite: softening point of 162 ° C.,
Penetration (25 ° C) 0, fixed carbon 16% powder (particle size 0.
3-2.5 mm). 2) Tackifier: solvent-extracted oil having the following physical properties (1)
And (2).

[0024]

[Table 1] Table 1 Solvent-extracted oil 12 Viscosity (cSt, 100 ℃) 25.10 55.36 Flash point (℃) 252 282 Aromatic and naphthene content (% by weight) 57.5 65.5

3) Polymer dispersion: S having the following physical properties
BS-based emulsion polymers (A), (B) and (C).

[Table 2] Table 2 Emulsion polymer ABC latex viscosity (cps) 450 180 270 Total solids (%) 70 50 50 Average particle size (μ) 0.3 0.05 0.15

4) Asphalt: 3 types (80/100, 60/80 and 40 / having the following penetration and softening point:
60)

[Table 3] Table 3 Asphalt 80/100 60/80 40/60 Penetration (25 ℃) 91 70 52 Softening point (℃) 47.5 49.5 50.5

[Test Method and Measurement of Various Physical Properties] In the present invention, the test method and various physical properties were measured according to the following methods or conditions. (1) Asphalt test Standard test (JIS K 2207) Penetration: 25 ° C (1/10 mm), Softening point: (° C), Elongation: 7 ° C, 15 ° C (cm), Viscosity: 180 ° C (cSt ), Thin film heating extension residual rate: (%). Frass embrittlement point: JIS K 2207, viscosity: 60 ° C. (poise) (published by Japan Road Association (issue date: November 10, 1988) “Pavement Test Method Handbook”). Toughness Tenacity (from "Handbook of Pavement Testing"). (2) Mixed material mixture test (according to "Handbook of Pavement Test Methods") Marshall stability test, wheel tracking test, labeling test.

Examples 1 to 5 and Comparative Examples 1 to 4 Powdery (particle size 0.3 to 2.5 mm) asphaltite, tackifier and polymer dispersion in the proportions shown in Tables 4 and 5,
Mix for 5 minutes at room temperature with a mixer to prepare a wet powder asphalt modifier, and then add 5 to 20 parts by weight of the asphalt modifier to 100 parts by weight of asphalt melted at 160 ° C to 170 ° C. Modified asphalt was produced by mixing in a mixer for 15-20 minutes with parts of formulation. Physical properties of the obtained modifier composition are shown in Tables 4 and 5. In addition, among the numerical values in the table, those with a + after the numeral indicate the indicated numeral or more, and those with a − after the numeral indicate the indicated numeral or less. Also, Table 5
Include modified asphalt type II and semi-blown asphalt (AC10
The standard value of 0) is also shown. Modified asphalt type II is a modified asphalt by adding a thermoplastic resin alone or by using a thermoplastic resin and a rubber-based polymer together. Semi-blown asphalt is a blowing operation (blow heated air into straight asphalt). It is a modified asphalt having improved temperature sensitivity and increased viscosity at 60 ° C.

[0029]

[Table 4]

[0030]

[Table 5]

The modified asphalts of Examples 1 to 5 have improved elongation, Frass embrittlement point and tenacity, as compared with those of Comparative Example 1, and are excellent in crack resistance. Moreover,
Since the viscosity at 180 ° C is low, workability and workability can be improved. In addition, as compared with that of Comparative Example 2, the softening point,
Viscosity at 60 ° C, toughness and tenacity are improved, and it has excellent flow resistance. Compared with that of Comparative Example 3, the softening point, the elongation, the Frass embrittlement point, the viscosity at 60 ° C. and the tenacity were improved, and the flow resistance and the crack resistance were excellent. Compared to that of Comparative Example 4, the elongation, the frass embrittlement point, and the tenacity were improved, and the crack resistance was excellent. Moreover, 180 ° C
Because of its low viscosity, it is possible to improve workability and workability.

Examples 6 and 7 To the aggregate heated to 160 ° C. to 170 ° C., 1
The asphalt 60/80 which was heated and melted at 50 ° C. and a wet powdery asphalt modifier were added and mixed by heating for 5 minutes with a mixer. Then, obtain the modified asphalt mixture,
Specimens for Marshall stability test, wheel tracking test and labeling test were prepared.

Comparative Examples 5 and 6 Asphalt was previously heated and mixed with an asphalt modifier to obtain a uniformly dispersed modified asphalt. Then, the modified asphalt was heated to 160 ° C., charged into an aggregate heated to 160 ° C. to 170 ° C., and heated and mixed by a mixer for 5 minutes. Then, a modified asphalt mixture was obtained to prepare specimens for a Marshall stability test, a wheel tracking test, and a labeling test.
The composition components of the modified asphalt are shown in Table 6, and the performance results of the obtained mixture are shown in Table 7.

[0034]

[Table 6] Table 6 Types of mixture Dense grain 20MM Dense grain 13MMF No. 5 crushed stone 16.1-6 No. crushed stone 23.6 28.1 Aggregate component No. 7 crushed stone 15.1 13.1 (wt%) Coarse sand 17.5 21.5 Net sand 17.0 22.4 Stone powder 5.3 8.4 Binder 5.5 6.5 Binder Component Example 6 (corresponding to Example 4) Asphalt 60/80 5.09 6.02 Asphalt modifier 0.41 0.48 Example 7 (corresponding to Example 2) Asphalt 60/80 4.66 5.51 Asphalt modifier 0.84 0.99 Comparative Example 5 Example Modified asphalt of 4 5.5 6.5 Comparative example 6 Modified asphalt of Example 2 5.5 6.5

[0035]

[Table 7]

The modified asphalt composites of Examples 6 and 7 were compared with those of Comparative Examples 5 and 6 by the Marshall stability test,
Since the composite material performance in the wheel tracking test and labeling test hardly changed, the asphalt modifier of the present invention is uniformly melt-dispersed in the asphalt and the aggregate to obtain a uniform modified asphalt composite material. I was confirmed. The modified asphalt mixture using the asphalt modifier of the present invention is asphalt 6
The dynamic stability of the wheel tracking test is large and the flow resistance is improved, as compared with the asphalt mixture using 0/80. In addition, compared with the modified asphalt mixture using the commercially available modified type II modified asphalt, the dynamic stability of the wheel tracking test and the mixture performance of the amount of abrasion in the labeling test are comparable. Got

From the above results, it is understood that the asphalt modifier of the present invention can be effectively used as a paving asphalt modifier which is required to have fluidity resistance, abrasion resistance, crack resistance and the like. In particular, the asphalt modifier of the present invention is an asphalt plant, and when mixing the asphalt and the aggregate, a small amount of a thermoplastic resin bag made of polyethylene or the like in a wet powder form is directly charged with the bag. Since it can produce modified asphalt mixture, it can be used as a plant-mix type paving asphalt modifier, which has the effect of preventing deterioration of the work environment such as dust scattering and the improvement of work efficiency. You can

Claims (10)

[Claims] 1. An asphalt modifier, which is obtained by mixing asphaltite, a tackifier and a polymer dispersion. 2. The blending ratio of each component is asphaltite 50 to 65% by weight, tackifier 25 to 35% by weight, and polymer dispersion 10 to 25% by weight. Asphalt modifier. 3. Asphaltite has a softening point of 130 to 2
The temperature is 00 ° C and the fixed carbon content is 10 to 20%.
Asphalt modifier. 4. The tackifier has a viscosity of 20 to 80 cSt /
The asphalt modifier according to claim 1 or 2, which is a solvent-extracted oil having a total of aromatic and naphthene contents of 45% by weight or more and a flash point of 220 ° C or more at 100 ° C. 5. A vinyl polymer-based polymer dispersion obtained by emulsion homopolymerization or emulsion copolymerization of a monomer selected from vinyl acetate-based, acrylic-based, vinylidene chloride-based and vinyl chloride-based monomers, 3. A synthetic rubber polymer dispersion obtained by emulsion homopolymerization or emulsion copolymerization of butadiene or a derivative thereof, the viscosity of which is 100 to 500 cps, and the modifier for asphalt according to claim 1 or 2. 6. The asphalt modifier for paving according to claim 1, wherein the asphalt is an asphalt for paving. 7. A method for modifying asphalt, characterized in that a modifier comprising asphaltite, a tackifier, and a polymer dispersion is blended in asphalt and kneaded. 8. Asphaltite 50 to 65% by weight, tackifier 25 to 35% by weight, and polymer dispersion 10 to 25.
% Of asphaltite is added to 100 parts by weight of asphalt.
8. The method for modifying asphalt according to claim 7, wherein the blending is carried out so as to be -13 parts by weight, 1.25-7 parts by weight of tackifier and 0.5-5 parts by weight of the polymer dispersion and kneading. 9. The method for modifying asphalt according to claim 7, wherein the bag is made of a thermoplastic resin and a small amount of the modifier is added to the bag. 10. The method for modifying pavement asphalt according to claim 7, wherein the asphalt is pavement asphalt.