JP2562094B2 - Granular asphalt containing inorganic particles and method for producing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a granular asphalt containing inorganic particles and a method for producing the same. In the present specification, "%" and "parts" mean "wt%" and "parts by weight", respectively.

[0002]

2. Description of the Related Art Asphalt is widely used as a road paving material, a waterproof material, a vibration damping material, a soundproofing material, and the like. However, since asphalt is a solid or semi-solid at room temperature, it needs to be constantly heated so as not to be solidified during transportation to the construction site. Further, at the time of use, it is necessary to carry out the work while the heat-melted asphalt does not solidify, or it is necessary to carry out the work while heating the semi-solid asphalt on site. For this reason, improvements in transportability, handleability, etc. have been demanded.

As a waterproof material, asphalt emulsion is used. This is to improve the transportability and handleability by emulsifying asphalt using water as a medium and imparting fluidity. However, since the asphalt emulsion contains water, it has poor drying property,
It has the drawback of limited use.

In order to solve such problems of asphalt, granulation of asphalt has been proposed and tried. Conventionally known asphalt granulation methods include a method in which asphalt is frozen and then mechanically crushed, a method in which an asphalt emulsion is spray-dried and granulated, and then microencapsulated.

[0005]

However, since the asphalt particles crushed after freezing do not have an anti-adhesion function (hereinafter referred to as an anti-adhesion function or an anti-adhesion property), they are adhered to each other and stored together at room temperature, It cannot retain its shape as particles.

The microencapsulated asphalt has improved anti-adhesion property and excellent room temperature storage property,
Since fine particles of 100 μm or less are encapsulated, it becomes extremely expensive and inferior in economic efficiency.

Therefore, the main object of the present invention is to provide a technique for inexpensively producing asphalt particles having excellent anti-adhesion properties.

[0008]

Means for Solving the Problems The present inventor has conducted extensive research in view of the current state of the art as described above, and as a result, in the case of adhering a specific fine powder to the surface of granular asphalt, It was found that the anti-adhesion property is improved. However, also in this case, if the particle size of the particles is small, the contact area between the particles is large, so that mutual adhesion cannot be completely prevented, and if a large amount is piled up, mutual fusion may be suppressed. Turned out not. On the other hand, it has been found that, when the particle size of the particles exceeds a certain level, the strength is insufficient and the particle shape cannot be maintained, and the particles collapse to cause fusion. After all, the granular asphalt with fine powder adhered to this surface can only be stored in small quantities in cans, bags, etc.
It has been found that the anti-adhesion property can be substantially improved.

As a result of further research, the present inventor has found that when an inorganic powder having a specific particle size is uniformly dispersed and contained inside the granular asphalt having the specific fine powder adhered to the surface as described above. Is a granular asphalt particle size of 0.1
It has been found that even if it is set to about 5 mm, the strength is improved and no collapse occurs. Then, in this case, since the contact area between the particles is reduced due to the increase in the particle diameter, it has been found that the fusion of the particles can be effectively prevented even if they are piled up in a large amount.

That is, the present invention provides a granular asphalt containing the following inorganic particles and a method for producing the same: Granular asphalt containing inorganic particles having the following characteristics: (1) The average particle size is 0.1 to 5.0 mm; (2) The BET specific surface area is 0.5 to 400 m ² / g. It is uniformly dispersed and contained; (3) The dispersed content of inorganic particles is 1 to 80 parts per 100 parts of asphalt; (4) Sulfate, silicate of alkaline earth metal and zinc,
Granular asphalt is a fine powder made of at least one selected from the group consisting of phosphates, carbonates, hydroxides and oxides, and having an average particle size of 0.5 to 20 μm as determined by light transmission particle size analysis. (5) The amount of fine powder used is 10 to 200 parts with respect to 100 parts of asphalt.

2. Asphalt has a softening point of 40-15
A granular asphalt containing the inorganic particles according to item 1, which is at least one of 0 ° C. straight asphalt, blown asphalt, propane deasphalting asphalt, elastomer-modified asphalt, and artificial synthetic asphalt.

3. A method for producing granular asphalt containing the inorganic particles according to the above item 1, which comprises the following steps: (1) Sulfate, silicate, phosphate of an alkaline earth metal and zinc while being stirred in an anionic surfactant aqueous solution. , carbonates, hydroxides and the fine powder of at least one selected from the group consisting of oxides charged, suspension Ru temper made to <br/>step; (2) heated and melted asphalt A step of mixing the inorganic particles having a BET specific surface area of 0.5 to 400 m ² / g with stirring; (3) stirring the suspension and the mixture obtained in the steps (1) and (2) above, respectively. Mix, granulate, dehydrate,
The process of drying.

4. Asphalt has a softening point of 40-15
5. A method for producing granular asphalt containing inorganic particles according to item 4, which is at least one of 0 ° C. straight asphalt, blown asphalt, propane deasphalting asphalt, elastomer-modified asphalt, and artificial synthetic asphalt.

The asphalt used in the present invention is not particularly limited and includes straight asphalt having a softening point of about 40 to 150 ° C., blown asphalt, propane deasphalting asphalt, elastomer modified asphalt, artificial synthetic asphalt and the like. These asphalts may be used as a mixture of two or more kinds.

In the present invention, as the inorganic particles uniformly dispersed and contained in the granular asphalt, those generally used as fillers in rubber, plastics, sealants and the like can be used as they are. More specifically, silicic acid anhydride, clay, talc, quartz powder,
Natural and synthetic silicic materials such as white carbon;
Examples thereof include metal oxides such as titanium oxide, calcium oxide, magnesium oxide and iron oxide; carbonates such as magnesium carbonate, calcium carbonate and zinc carbonate; carbon black such as furnace black, channel black and thermal black. These inorganic particles may be used alone or in combination of two or more kinds. B of inorganic particles
The ET specific surface area is preferably about 0.5 to 400 m ² / g. BET specific surface area of inorganic particles is 0.5m
^{When the amount} is less than ² / g, the inorganic particles become coarse and impair the performance of asphalt, while 400 m ²
If it exceeds / g, mixing into asphalt becomes difficult. The dispersed content with respect to 100 parts of asphalt may vary within a wide range depending on the BET specific surface area of the inorganic particles and the like, but it is preferably within the range of 1 to 80 parts. When the amount of the inorganic particles is small, the internal cohesive force of the granular asphalt is not sufficiently strengthened, so that the granular asphalt is likely to be deformed and flow when piled up at the time of storage, and the anti-adhesion property is not sufficiently exhibited. On the other hand, when the amount of the inorganic particles is excessive, the granulation itself becomes difficult, and the asphalt properties are impaired.

The fine powder to be adhered to the surface of the granular asphalt includes alkaline earth metals such as calcium, barium and magnesium and zinc sulfates, silicates, phosphates,
It comprises at least one selected from the group consisting of carbonates, hydroxides and oxides. Further, the average particle diameter obtained by the light transmission particle size analysis method needs to be 0.5 to 20 μm. When the average particle size of the fine powder is less than 0.5 μm, the amount of attached water increases, which causes foaming during heating and melting of asphalt. On the other hand, when it exceeds 20 μm, coarse particles are present in the asphalt product, which is not preferable. The amount of fine powder used is
It is about 10 to 200 parts per 100 parts of asphalt. If the amount of the fine powder used is too small, it becomes difficult to prevent the mutual adhesion of the granular asphalt, whereas if the amount is too large, the amount of the fine powder present in the free state increases and the asphalt Hinder the performance of. However, when assuming a situation in which a large amount of granular asphalt is present in contact with each other, a small amount of free fine powder may exert an action as an adhesion preventive agent between the granular asphalts, which is particularly disadvantageous. is not.

The granular asphalt according to the present invention is manufactured by the following steps.

(1) Step 1 First, the above-mentioned alkaline earth metal and zinc sulfate, silicate, phosphate, carbonate, hydroxide and oxide are added to an anionic surfactant aqueous solution with stirring. A fine powder consisting of at least one selected from the group is added to prepare a suspension. This fine powder not only suppresses mutual fusion of the granular asphalt, which is the final product, but also prevents mutual adhesion of the granular asphalt that is being formed in the asphalt granulation process described below.

As the surface active agent, one which is converted into an insoluble metal salt by a metathesis reaction with a small amount of metal ions dissolved in water derived from the fine powder is used. Examples of such anionic surfactants include those having 10 carbon atoms.
Above fatty acid alkali metal salts, naphthenic acid alkali metal salts, resin acid alkali metal salts, alpha olefin sulfonic acid sulfuric acid ester, alkylbenzene sulfonic acid sulfuric acid ester, alkyl (phenyl) sulfuric acid ester, methyl tauric acid alkali metal salt, sulfosuccinic acid alkali metal Examples include salt. The insoluble metal salt formed as described above is deposited on the surface of the fine powder to hydrophobize the surface, and the hydrophobized surface is firmly bound to the lipophilic asphalt surface. From this point of view, metal salts having high solubility such as calcium chloride cannot be used as fine powder in the present invention.

The surfactant varies depending on the type of fine powder, its average particle size, etc. Theoretically, the surface of the fine powder is formed by forming an adsorption layer of a surfactant consisting of a single molecule on the fine powder surface. It is sufficient to use an amount sufficient for making the material hydrophobic. Such a theoretical amount can be easily obtained by calculation, but when a large excess amount is used, unreacted surfactant remains on the surface of the fine powder to make the fine powder hydrophilic. Therefore, it is not preferable. Therefore, the amount of the surfactant used is preferably close to the theoretical amount.

[0021] The amount of the fine powder is preferably set to 20 to 150 parts per 100 parts of water in the aqueous surfactant solution. When the amount of the fine powder is too small, the asphalt becomes difficult to be granulated in the step 3 described later, while when the amount of the fine powder is too large, the asphalt does not adhere to the surface of the granular asphalt and exists in a free state. The amount of fine powder increases, which hinders the performance of asphalt.

(2) Step 2 On the other hand, the asphalt that has been heated and melted is mixed with inorganic particles with stirring to prepare an asphalt-inorganic particle mixture. The mixing ratio of the asphalt and the inorganic particles is 1 to 100 parts of the asphalt as described above.
The ratio is 80 parts.

(3) Step 3 Next, the fine powder suspension obtained in Step 1 and the asphalt-inorganic particle mixture obtained in Step 2 are mixed under heating. When the softening point of the asphalt is 100 ° C. or lower, the fine powder suspension obtained in step 1 may be heated above the softening point of the asphalt to mechanically mix the two in an open system. If the asphalt has a softening point of 100 ° C or higher, both are placed in a pressure-tight container equipped with a stirrer such as an autoclave and then heated, and stirring is started when the vapor pressure at a predetermined temperature is reached. Good. The mixing ratio of the fine powder suspension and the asphalt-inorganic particle mixture may be 30 to 100 parts of the latter asphalt to 100 parts of the former water. If the amount of asphalt with respect to water is too small, the heat energy required for heating to a predetermined temperature becomes large, which is uneconomical. On the other hand, when the amount of asphalt is excessive, the amount of water that forms the continuous phase is insufficient, and it becomes difficult to granulate the asphalt in a stable state.

Thus, granular asphalt is formed in the continuous phase of water during continuous stirring. The particle size of the granular asphalt can be controlled mainly by selecting the stirring speed and stirring time. For example, in general, when the stirring speed is increased and stirring is completed within a short time, granular asphalt having a small average particle diameter can be obtained. In contrast,
When the stirring speed is reduced and stirring is continued for a long time, granular asphalt having a large average particle diameter can be produced.

The granular asphalt formed in water is then dehydrated and dried to the desired product.

[0026]

EFFECTS OF THE INVENTION According to the present invention, it is possible to produce granular asphalt having excellent anti-adhesion property, high strength and large particle size.

Therefore, such granular asphalt can be stored, for example, in a piled state under normal temperature conditions without accommodating a small amount in a specific container.

[0028]

EXAMPLES Examples are shown below to further clarify the features of the present invention.

Example 1 2 g of sodium stearate was added to 5 kg of water, 2.5 kg of calcium carbonate having an average particle size of 5 μm was added, and a uniform dispersion was prepared by high speed mechanical stirring (product of step 1).

On the other hand, straight asphalt (penetration: 6
0-80, softening point 44-52 ℃) 3.5kg diameter 30
1 kg of quartz powder having a BET specific surface area of 3.0 m ² / g while being housed in a metal container of 0 mm x length of 500 mm, externally heated to 100 ° C by an electric heater and mechanically stirred.
Were mixed and dispersed (Step 2 product).

Then, the product of step 1 heated to 80 ° C. is rapidly added to the product of step 2 kept at 100 ° C., mechanical stirring (400 rpm) is started at the same time as the addition, and stirring is continued for 10 minutes. Granulation of asphalt was performed.
The entire system was then cooled to room temperature, dehydrated and dried to give the desired product.

Example 2 A granular asphalt was obtained in the same manner as in Example 1 except that artificial synthetic asphalt (penetration: 72, softening point: 50 ° C.) was used in place of the straight asphalt.

Example 3 A granular asphalt was obtained in the same manner as in Example 1 except that 10 g of sodium stearate and 2.5 kg of calcium carbonate having an average particle size of 1.3 μm were used in Step 1.

Example 4 A granular asphalt was obtained in the same manner as in Example 1 except that 11 g of sodium stearate and 2.5 kg of zinc oxide having an average particle size of 0.6 μm were used in Step 1.

Examples 5 to 7 Granular asphalt was produced in the same manner as in Example 1 except that the following inorganic particles were used in place of 1 kg of quartz in Step 2.

Example 5: BET specific surface area 100 m ² /
g of silicic anhydride 0.14 kg-Example 6: 0.35 kg of SRF black having a BET specific surface area of 29 m ² / g-Example 7: 1 kg of calcium oxide having a BET specific surface area of 2.5 m ² / g Example 8 stearin in 500 g of water Sodium acid 0.8g was added, and 200g barium carbonate with an average particle size of 0.8μm.
Was added and a uniform dispersion was prepared by high speed mechanical stirring (Step 1 product).

On the other hand, blown asphalt (penetration of 20
-40, softening point of 100 ° C or higher) 350 g of which is heated and melted at 150 ° C, and then mechanically stirred to have a BET specific surface area 1
100 g of 0 m ² / g talc were mixed and dispersed (Step 2 product).

Then, the product of step 1 and the product of step 2 were simultaneously charged into an autoclave having a volume of 2 liters equipped with a stirrer, and when heating was performed to start vapor pressure to reach 4 kg / cm ² , stirring was started, Agitation was continued for 7 minutes for granulation.
Then, the water-containing granular material was taken out into the atmosphere, cooled to room temperature, dehydrated, and dried to obtain a desired product.

Example 9 A granular asphalt was obtained in the same manner as in Example 3 except that an elastomer-modified asphalt (penetration: 30, softening point: 110 ° C.) was used instead of the blown asphalt.

Example 10 A granular asphalt was produced in the same manner as in Example 1 except that sodium resinate was used instead of sodium stearate.

Example 11 A granular asphalt was produced in the same manner as in Example 1 except that sodium alkylbenzenesulfonate was used instead of sodium stearate.

Example 12 Sodium resinate was used in place of sodium stearate, and granulation was performed in the same manner as in Example 8 to obtain granular asphalt.

Example 13 Granular asphalt was obtained by using sodium alkylbenzene sulfonate instead of sodium stearate and granulating in the same manner as in Example 8.

Comparative Examples 1-2 The amount of calcium carbonate used in Step 1 of Example 1 was
0.28 kg (Comparative Example 1) or 7.5 kg (Comparative Example
Granular asphalt was obtained in the same manner as in Example 1 except for 2) .

Comparative Examples 3 to 4 In Step 2 of Example 1, 30 g of silicic acid anhydride having a BET specific surface area of 200 m ² / g is used instead of the quartz powder (Comparative Example 3) or quartz having a BET specific surface area of 3 m ² / g. Powder
Granular asphalt was obtained in the same manner as in Example 1 except that 3.2 kg was used (Comparative Example 4).

Comparative Examples 5 to 6 Nonylphenol polyoxyethylene (nonionic type, HLB8.
Granular asphalt was obtained in the same manner as in Example 1 except that 8) was used (Comparative Example 5) or stearyl trimethylene ammonium chloride (cationic system) was used (Comparative Example 6).

Test Example 1 With respect to the granular asphalts obtained in the above Examples and Comparative Examples, the degree of granulation by mechanical stirring, the average particle size,
The anti-adhesion property, the tackiness at the time of heat melting, and the penetration degree were measured. The results are shown in Table 1.

In Table 1, the average particle size, anti-adhesion property and tackiness during heat melting were measured as follows.

-Average particle size ... The dried granular asphalt was subjected to dry sieving to examine the particle size distribution.

-Anti-adhesion property: 10 g of the sample was 4.5 cm x 4.
Put it in a 5 cm x 0.5 cm bag and put it at room temperature at 25 g / cm ²
(For straight asphalt) or 140g / c
Load m ² (for blown asphalt) 2
The presence or absence of solidification after leaving for a week was examined.

-Adhesiveness at the time of heat melting: The straight asphalt granules were heated to 100 ° C, and the blown asphalt granules were heated to 150 ° C to evaluate the tackiness of the hot melt.

Penetration: Measured at 25 ° C. and 100 g.

Table 1 Granulation Situation Average particle size (mm) Anti-adhesion property Hot melt Penetration Stickiness of Example 1 Stabilized granulation 0.2 to 1.0 None, high tackiness 25 2 〃 0.2 to 2.0 〃 〃 20 3 〃 0.2 to 3.0 〃 〃 23 4 〃 0.3 to 4.5 〃 〃 25 〃 0.4 to 5.0 〃 26 〃 26 〜4.0 〃 〃 21 7 〃 0.2 〜 1.5 〃 〃 30 8 〃 0.5 〜 1.3 〃 〃 15 9 〃 0.5 〜 2.0 〃 13 〃 28 〃 0.1 〜 0.7 〃 〃 30 11 〃 0.3 11 〃 0.3 11 〃 〃 〃 20 13 〃 0.2 to 1.1 〃 〃 18 Comparative Example 1 No granulation − − − − 2 Stable granulation 0.1 to 0.5 No stickiness small 8 3 〃 0.05 to 0.1 integrated sticky 60 4 product hard − − − − No granulation 5 Stable granulation 0.01 to 1.0 Integrated tackiness 25 6 Stable granulation 0.01 to 1.0 Integrated tackiness 25 From the results shown in Table 1, the excellent properties of the granulated asphalt according to the present invention are shown. it is obvious.

 ─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-62-201944 (JP, A) JP-B-47-40536 (JP, B1)

Claims (4)

(57) [Claims] 1. A granular asphalt containing inorganic particles having the following characteristics: (1) an average particle diameter of 0.1 to 5.0 mm; (2) a BET specific surface area of 0.5 to 400 m ² / g. Inorganic particles are uniformly dispersed and contained therein; (3) The dispersed content of the inorganic particles per 100 parts of asphalt is 1 to 80 parts; (4) Sulfate and silicate of alkaline earth metal and zinc ,
Granular asphalt is a fine powder made of at least one selected from the group consisting of phosphates, carbonates, hydroxides and oxides, and having an average particle size of 0.5 to 20 μm as determined by light transmission particle size analysis. (5) The amount of fine powder used is 10 to 200 parts with respect to 100 parts of asphalt. 2. The inorganic particles according to claim 1, wherein the asphalt is at least one of straight asphalt having a softening point of 40 to 150 ° C., blown asphalt, propane deasphalting asphalt, elastomer modified asphalt and artificial synthetic asphalt. Granular asphalt. 3. A method for producing granular asphalt containing inorganic particles according to claim 1, which comprises the following steps: (1) Alkaline earth metal and zinc sulfate and silicic acid in an anionic surfactant aqueous solution with stirring. salts, phosphates, carbonates, hydroxides and the fine powder of at least one selected from the group consisting of oxides charged, suspension Ru temper made to <br/>step; (2 ) A step of mixing the heat-melted asphalt with inorganic particles having a BET specific surface area of 0.5 to 400 m ² / g with stirring; (3) The suspension obtained in each of the above steps (1) and (2). And agitating the mixture, granulating, dehydrating and drying. 4. The inorganic particles according to claim 3, wherein the asphalt is at least one of straight asphalt having a softening point of 40 to 150 ° C., blown asphalt, propane deasphalting asphalt, elastomer-modified asphalt, and artificial synthetic asphalt. Manufacturing method of granular asphalt.