JPH0657148A - Surface course material for colored pavement and its production - Google Patents

Abstract

PURPOSE:To produce the surface course material which can give a paved road of a high dynamic stability on the site of a pavement work or in an asphalt plant without causing dusting by coloring a bituminous material with a coloring masterbatch prepared by dispersing pigment particles in a thermoplastic resin. CONSTITUTION:This material is prepared by coloring a bituminous material with a coloring masterbatch. The bituminous material comprises at least one member selected from among asphalt, tar, etc. Especially, a decolored asphalt can be effectively colored with a small amount of the masterbatch. The coloring masterbatch can be obtained by kneading a molten thermoplastic resin with a large amount of pigment particles in a pigment to thermoplastic resin ratio of usually 50:50 by weight, and coloring the obtained mixture. The pigment may be an inorganic or organic one and is desirably inorganic one excellent in weathering resistance, hiding power and chemical resistance. As the thermoplastic resin, a polyethylene of a weight-average molecular weight of 10000 or above is desirably-used. The bituminous material us colored by adding the masterbatch to an aggregate, dry-mixing the obtained mixture, adding a molten asphalt to the mixture, and mixing the entire lot.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colored pavement surface layer material and a method for producing the same.

[0002]

2. Description of the Related Art Pavement roads are finished by using bituminous materials (bitumen; hereinafter the same) such as asphalt as a surface binder. The road surface of the paved road has a dark dark color due to the bituminous material. On the roadway, the route classification and the passing vehicle classification are currently displayed by an arrow or a road sign drawn on the road surface. If the sections can be identified by the color of the road surface, the vehicle driver can easily recognize the sections, which is useful for safe driving and smooth vehicle operation.

In a promenade or an amusement park passage, not only a dark and dark road surface but also a road surface of a desired color makes the route easy to understand and the scenery is colored. Therefore, it was considered to color the surface of the paved road. Asphalt is colored by spray-mixing asphalt at a plant or pavement site where pigments such as rouge (Fe ₂ O ₃ ) and chromium oxide (Cr ₂ O ₃ ) are directly mixed with aggregate such as gravel. Be seen.

[0004]

The pigment used for coloring the asphalt is a very fine particle of, for example, 0.1 to 0.3 μm, so that the pigment particles are greatly scattered when metered, charged or mixed. , Significantly deteriorates the working environment and adversely affects the health and safety of workers. In addition, even if you try to automate the work such as weighing, adding, and mixing pigments,
Since the pigment particles are fine, the fluidity is poor, automation is not possible, and human resources have to be relied upon.

In order to improve these drawbacks, it has been considered to use a pigment such as a valve pattern which is granulated and processed into a bead shape, but it is scattered when it is put into an aggregate or the like and stirred. The current situation is that the problems have not been resolved and continue to this day. On the other hand, the more paved roads pass, the more likely they are to be damaged, and therefore high dynamic stability is required.

An object of the present invention is to provide a colored paving surface material which can automate coloring work of bituminous materials such as asphalt and is useful for making paved roads having high dynamic stability. An object of the present invention is to provide a method for easily producing a colored pavement surface material at a pavement site, an asphalt plant, or the like without generating dust.

[0007]

In order to solve the above-mentioned problems, the present invention provides a colored pavement surface material for paving in which a paving aggregate and a bituminous material are mixed, wherein the bituminous material is contained in a large amount. A colored pavement surface layer material characterized by being colored with a coloring masterbatch obtained by dispersing the pigment particles of 1. in a thermoplastic resin.

The present invention, in order to solve the above problems,
A bituminous material is obtained by mixing a coloring masterbatch in which a large amount of pigment particles are dispersed in a thermoplastic resin with a heated paving aggregate and then mixing it with a liquid bituminous material. Provided is a method for producing a colored pavement surface material for coloring.
The bituminous material used in the present invention is at least one selected from asphalt, tar and the like. As the asphalt, for example, petroleum asphalt, natural asphalt, asphalt cement, decolorized asphalt and the like are used. The decolorized asphalt can enhance the coloring effect with a small amount of use, and is particularly advantageous in terms of the coloring effect when coloring with a pigment having a weak coloring power. As the tar, for example, crude tar (coal tar, oil tar, etc.) is further distilled to distill out a part of water and volatile substances. Either of two types, one for room temperature and one for heating Or more than one is used.

The pigment used in the present invention may be either an inorganic pigment or an organic pigment and is not particularly limited, but an inorganic pigment excellent in weather resistance, hiding power and chemical resistance is preferable.
As such an inorganic pigment, for example, red iron oxide, chromium oxide, yellow iron oxide and titanium dioxide are particularly preferable. Since the organic pigment has a low hiding power, it is used in combination with a pigment having a hiding power such as titanium dioxide when increasing the hiding power. Organic pigments are generally inferior in weather resistance to inorganic pigments, but among them, copper phthalocyanine blue, copper phthalocyanine green, quinacridone red, which are excellent in weather resistance,
Perylene red, tetrachloroisoindolinone yellow, etc. are used.

The thermoplastic resin used in the present invention is polyethylene, polypropylene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, etc., and any one of them may be used alone or two or more of them may be used in combination. Or Polyethylene has a weight average molecular weight of 1
For example, one selected from low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, or the like may be used, or two or more may be used in combination.

The coloring masterbatch used in the present invention is obtained by putting a large amount of pigment particles in a heat-melted thermoplastic resin and kneading the mixture to make it a cooled solid. At this time, the pigment particles fly up to generate dust, which is removed by kneading with a kneading device such as an extruder or an integral mixer in a closed state.

The coloring masterbatch comprises a thermoplastic resin and a pigment which are kneaded by heating to contain the pigment in a high concentration. The weight ratio of the thermoplastic resin to the pigment is influenced by the oil absorption amount of each pigment, but normally, pigment: thermoplastic resin = 5
Although it is 0:50 (weight ratio), the higher the proportion of the pigment, the better, and preferably pigment: thermoplastic resin = 70: 30-9.
It is in the range of 0:10 (weight ratio). Pigment ratio is 50:
If it is less than 50, a large amount of the coloring masterbatch will be used for coloring the bituminous material, which may increase the cost, and if it is more than 90:10, the coloring masterbatch may not be pellets or bitumen. When the material is colored, the coloring masterbatch may be poorly dissolved in the bituminous material.

The coloring masterbatch used in the present invention may be composed of only the pigment and the thermoplastic resin, but may contain other additives. Examples of such additives include metal soap for favorably dispersing the pigment in the resin, polyethylene wax (polyethylene having a weight average molecular weight of less than 10,000) for adjusting the hardness of the bituminous material, APP. (Atactic polypropylene) and the like, and any one or two or more thereof are used.

The shape of the coloring masterbatch used in the present invention is not particularly limited, and various shapes such as square pellets, round pellets, and cylindrical pellets can be adopted, and one side is 2-3 mm. Square pellets, diameter 2 ~
A cylinder having a length of 3 mm and a length of 2 to 3 mm is particularly preferable. If it is larger than this, there is a risk of dissolution failure, and if it is smaller, the weighing accuracy during automatic weighing may be deteriorated. To obtain the coloring masterbatch as pellets, heat and knead with a two-roll mill, stretch into a sheet, and then use a square pelletizer to
Any method such as a method of extruding a prism having a diameter of -5 mm or a thickness of 3-5 mm with a continuous extruder, cooling in a water tank, and cutting into a length of 2-5 mm may be used.

The pavement aggregate used in the present invention is not particularly limited as long as it is a granular material. For example, gravel, crushed stone,
Desired particles from coarse aggregate to fine particles, which are generally used in asphalt pavement, such as sand and filler. In the present invention, for coloring the bituminous material using the coloring masterbatch, for example, the following method is adopted. In the production of an asphalt mixture in a conventional asphalt plant, usually, a required amount of pavement aggregate accumulated by heating and drying is weighed and heated to 180 to 200 ° C. in a kiln,
Add it to the aggregate by spraying molten asphalt in a mixer,
The mixture is mixed for about 60 seconds. Before the asphalt is added by the mixer, the coloring masterbatch is added to the aggregate and mixed for about 5 seconds by a dry method, and then the molten asphalt is added and mixed. During this mixing, the components (color pigment, thermoplastic resin, and additives used as necessary) in the masterbatch are also melted and dispersed in the bituminous material. As a result, the bituminous material is colored and a colored paving surface material is obtained. The use of a coloring masterbatch allows automated weighing.

In the colored pavement surface material of the present invention, the use ratio of the bituminous material and the pavement aggregate is appropriately set according to the grade and application of the paved road. For example, asphalt used for conventional paved roads. The range of usage ratios adopted in the mixture is adopted. The amount of the coloring masterbatch used for coloring the bituminous material is not particularly limited as long as it is an amount sufficient for coloring the bituminous material. For example, with respect to 100 parts by weight of the bituminous material. A ratio of 6 to 10 parts by weight is preferable. If it is less than this range, the color of the bituminous material may be erased and desired coloring may not be possible, and if it exceeds this range, the physical strength may be adversely affected, or the coloring price may be higher than the coloring effect. When the bituminous material is decolorized asphalt, the amount of the coloring masterbatch used can be smaller than the above range, for example, 2 to 8 parts by weight.

When the surface layer of a road pavement is prepared using the colored paving surface material of the present invention obtained as described above, the colored bituminous material serves as a binder for the paving aggregate. How to use the colored pavement surface material of the present invention (paving method, etc.)
Is the same as the conventional method of using the pavement surface material. A paved road made using the colored pavement surface material of the present invention,
Since the bituminous material used for the binder of the surface layer is colored with a pigment, the bituminous material has a road surface that exhibits a desired color rather than the dark dark color originally possessed.

[0018]

In the present invention, since the bituminous material is colored by the coloring masterbatch in which a large amount of pigment particles are dispersed in the thermoplastic resin, a large amount of pigment dust is generated during the coloring work of the bituminous material. There is no problem, work becomes easy, and automation can be achieved. Moreover, since the thermoplastic resin used in the coloring masterbatch is added to the bituminous material and dispersed by the coloring operation, the bituminous material thus colored is used as the binder of the aggregate of the pavement surface layer. When used for paving, a colored paved road with high dynamic stability can be obtained.

[0019]

EXAMPLES Specific examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples. (Reference Example 1) 70 kg of valve stem (Fe ₂ O ₃ ) and 30 low-density polyethylene in a 200-liter drum tumbler
kg and 2.5 kg of zinc stearate were added and mixed for 20 minutes. This mixture was heated and kneaded with a twin-screw extruder, and the diameter was 3 m.
A pellet-shaped colorant composition (masterbatch for coloring) having a length of m and a length of 3 mm was obtained.

(Reference Example 2) 120 kg of chromium oxide (Cr ₂ O ₃ ), 30 kg of low-density polyethylene and 4.0 kg of polyethylene wax were put into a 200-liter high speed mixer and mixed for 2 minutes. This mixture was kneaded by heating with a single-screw extruder to obtain a pellet-shaped colorant composition (coloring masterbatch) having a diameter of 2 mm and a length of 2 mm.

(Example 1) 940 kg of asphalt composition against 60 kg of the colorant composition obtained in Reference Example 1 above
(Breakdown: Asphalt 42.5kg, Gravel 897.5kg)
The mixture was stirred for 60 seconds in a heated melting pot to melt-mix the colorant composition and asphalt, and then the red colored paving surface material was taken out. During this series of work, no dust was generated and the work could be performed easily. Further, the colorant composition had a pellet shape and had good fluidity and could be automatically measured.

Example 2 60 kg of the colorant composition obtained in Reference Example 2 above is 940 kg of the asphalt composition.
(Breakdown: 36.5 kg asphalt, 903.5 kg gravel)
Was melted and mixed with the colorant composition and asphalt by stirring for 60 seconds in a heated melting pot, and then a green colored paving surface material was taken out. During this series of work, no dust was generated and the work could be performed easily. Further, the colorant composition had a pellet shape and had good fluidity and could be automatically measured.

(Comparative Example 1) A colored pavement surface material was obtained by repeating the same operation as in Example 1 except that 41 kg of valve pattern was used in place of the colorant composition in Example 1, but the valve pattern was changed. There was no choice but to manually put it in the melting pot, and moreover, a large amount of dust was generated, making the work difficult. (Comparative Example 2) A colored pavement surface material was obtained by repeating the same operation as in Example 2 except that 47 kg of chromium oxide was used instead of the colorant composition in Example 2, but the same as in Comparative Example 1. It was the result. [Test Method] The dynamic stability (DS) of the colored pavement surface materials of Examples 1 and 2 and Comparative Examples 1 and 2 was examined by a wheel tracking test. The result is the sample density,
It is shown in Table 1 together with the standard density and the compaction degree.

[0024]

[Table 1]

As shown in Table 1, the colored pavement surface materials of Examples 1 and 2 are significantly improved in dynamic stability as compared with those of Comparative Examples 1 and 2, and the surface layer of the pavement as an asphalt mixture is used. Can be used to make colored paved roads with less dents on the road surface.

[0026]

INDUSTRIAL APPLICABILITY The colored pavement surface material of the present invention is useful for making a paved road which is easy to color and has a high dynamic stability. According to the method for producing a colored pavement surface material of the present invention, such a colored pavement surface material can be easily produced at a pavement site or an asphalt plant without generating dust.

Claims (2)

[Claims] 1. A colored pavement surface layer material obtained by mixing a paving aggregate and a bituminous material, wherein the bituminous material comprises a large amount of pigment particles dispersed in a thermoplastic resin. A colored pavement surface material characterized by being colored in batches. 2. A coloring masterbatch obtained by dispersing a large amount of pigment particles in a thermoplastic resin is mixed with a heated paving aggregate and then mixed with a liquid bituminous material. , A method for producing a colored pavement surface material for coloring a bituminous material.