JPH02228363A - Room temperature-hardening asphaltic material and preparation thereof - Google Patents

Abstract

PURPOSE:To improve the adhesive properties to aggregates, application properties at room temp., load bearing strength, Marshal stiffness, etc., by compounding calcium carbonate, a specific straight asphalt, a modified polyethylene, a surfactant, and a lubricant. CONSTITUTION:85-98wt.% calcium carbonate (aggregate) (e.g. limestone) heated to 120-200 deg.C and having a particle diameter of 1-10mm is mixed with 15-2wt.% straight asphalt with a rate of penetration of 40-100. Then, 3-20wt.% (based on said asphalt, the same applies hereunder) modified polyethylene with an m.p. of 90-120 deg.C and an acid value of 0.1-100 and having carboxyl groups or groups derived from carboxyl groups, 2-10wt.% surfactant (e.g. polyoxyethylene alkyl ether), and 5-40wt.% lubricating oil (e.g. machine oil) with a specific gravity of 0.82-0.98 and a flashpoint of 150-300 deg.C are added thereto under stirring. The resulting mixture is allowed to cool to room temp.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an asphalt room temperature curing composite material.

Specifically, it relates to an asphalt room-temperature-curing composite material that has excellent adhesion to aggregate, can be applied at room temperature, has good productivity, and can provide a road paving material that has properties equivalent to load strength and Marshall stiffness. It is.

(Prior art) A composition made by blending asphalt with aggregate is relatively stable, has excellent frictional properties, does not require a long curing period during construction, and is inexpensive, making it suitable for roads. It is widely used as a paving material.

However, as the viscosity of asphalt is highly temperature dependent, it has drawbacks such as softening in the summer and causing rutting (and hardening in the winter, causing cracks and severe wear due to traffic such as chains). In addition, since the adhesive strength at the bonding surface between aggregate or base material, which is generally an inorganic material, and asphalt is weak, water tends to penetrate into the bonding surface and cause the asphalt to peel off.The peeling resistance of this asphalt As a way to improve the average molecular weight of asphalt,
A method of adding a specific amount of a maleated organic compound having an acid value of 10 to 10,000 and an acid value of 10 to 250 has been proposed (Japanese Patent Publication No. 61-26589). However, this method cannot improve peeling resistance. Although effective, it has the drawback that rutting resistance is not improved at all.

Modified asphalt is also known, which is made by blending specific modified polyethylene with asphalt (Japanese Patent Laid-Open No. 62-275
160), this modified asphalt has excellent paved road surface properties including rutting resistance, but it was said that heating construction was required.

(Problems to be Solved by the Invention) Asphalt mixtures made by blending the above-mentioned modified asphalt into aggregate at high temperatures of 120 to 200°C are prepared for each construction, and are constructed while maintaining high temperatures of approximately 120 to 150°C. It needs to be transported to the site. This high-temperature heating mixture is used in large quantities in large-scale, continuous pavement work, but it was not economical for small-scale or partial renovation work.

~]1 It was also necessary to add cantback asphalt oil or the like to which gasoline or kerosene was added as an asphalt room-temperature curing mixture, which required a complicated process.

(Means for Solving the Problems) The present inventors have found that the present invention is capable of being stored at room temperature for a long period of time, can be constructed at room temperature, is suitable for small-scale and easy construction, and has excellent load strength, marshall stiffness, etc. As a result of intensive studies to obtain an asphalt room-temperature-curing composite material, we found that calcium carbonate or magnesium carbonate-based aggregate, penetration rate 40-1
00 straight asphalt, having a carboxyl group or a group derived from a carboxyl group, melting point 90-1
The inventors have completed the present invention by discovering that the above object can be achieved by an asphalt cold-curing composite material consisting of modified polyethylene at 20°C, a surfactant, and a lubricating oil.

Furthermore, in producing the asphalt cold-curing mixture, since the flash point of lubricating oil is high, aggregates heated to 120 to 200°C are combined with other raw materials such as straight asphalt, modified polyethylene, surfactants, and lubricating oil. can be added at once, and is easier to manufacture in terms of safety and handling than when gasoline or kerosene is used.

The present invention will be explained in detail below.

In the present invention, calcium carbonate or magnesium carbonate-based aggregates are used. Limestone is suitable as an aggregate containing calcium carbonate as a main component. Also Ca
Dolomite (with a composition represented by CO3/MgC0)
Dolomite) is also preferably used. The composition of dolostone is Ca
It can also be expressed as Mg (COs)z, but there are few naturally occurring pure ones, and it is expressed as Ca (M
It often contains small amounts of other elements X in the form gX)(C03)2. In the above formula, X is Fe, Go, Ni, P
b.

Examples include Mn, Zn, Cu, Cr, Ba, and ACSr. Of course, a mixture of limestone and dolomite can also be used as aggregate. The aggregate is crushed and sieved to a particle size of 1 to 10 μl, preferably 3 to 7 μl. The present invention uses calcium carbonate or magnesium carbonate aggregate as the main component. However, a small amount of 40% by weight or less of aggregate such as sandstone, basalt, andesite, river gravel, river sand, sea sand, artificial aggregate, etc. can be mixed and used. The carbonate aggregate of the present invention is characterized by being crushed by a relatively small impact force and having a rough crushed surface. It is presumed that this contributes to improved adhesion (@ release test) with straight asphalt and modified polyethylene. Furthermore, during the tamping operation after applying the asphalt cold-curing mixture, some of the carbonate aggregates are crushed and the surface area increases, and this causes the lubricating oil to volatilize or to the aggregates due to the action of the surfactant. 'Twoll
& Promotes adhesion and hardening.

...-1'' In the present invention, the penetration is 4 as straight asphalt.
A value of 0 to 100 is used. Straight asphalt and blown asphalt with a penetration degree of less than 40 have too high a softening point and do not have sufficient affinity with the modified polyethylene and lubricating oil used in the present invention. On the other hand, straight asphalt with a penetration of over 100 has a softening point of 40.
℃ or below, causing problems with the load strength of the hardened asphalt mixture. Softening and rutting, especially in the summer, are a problem.

The modified polyethylene used in the present invention includes modification of polyethylene with an unsaturated carboxylic acid and/or a derivative thereof, modification of polyethylene by oxidative decomposition with oxygen, etc.
or a combination thereof, and contains a carboxyl group and/or a group derived from a carboxyl group in its molecule.

Modified polyethylene usually has an acid value of 0.1 to 100,
Preferably it is 0.1 to less than 10.

If the acid value is less than 0.1, the water resistance and peeling resistance will not be sufficient, and if the acid value is more than 100, the adhesion will be improved, but the temperature sensitivity will be suppressed in the high temperature range. It is not preferred because the durability is not sufficient. The above acid value is determined by dissolving 1 g of the sample in 100 mJ of varaxylene and titrating the solution at 135°C with potassium hydroxide using phenolphthalein as an indicator at 120°C, preferably 100 to 115°C.

When the melting point is 90°C or lower, uniform mixing with asphalt is sufficient, but temperature sensitivity is not sufficiently suppressed, and when the melting point is 120°C or higher, the iron wheel roller after construction, The flow of the mixture is large when compacted with tire rollers,
The finished surface is rough (undesirable).

As for the melting point, in differential thermal scanning analysis, the much-anticipated maximum endothermic peak temperature was used, which was obtained by heating a 10-inch sample at a rate of 10° C./min in a nitrogen atmosphere.

Polyethylene that is a raw material for modified polyethylene includes high-pressure low-density polyethylene, linear low-density polyethylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-propylene-butadiene copolymer, and ethylene-vinyl acetate copolymer. These can be used alone or in mixtures.

As a method for modifying polyethylene, a modification method in which an unsaturated carboxylic acid and/or a derivative thereof is grafted onto raw polyethylene is particularly suitable. As the raw material polyethylene, either one produced by a normal polymerization method or one obtained by pulverizing a molded product can be used. When graft-polymerized modified polyethylene is directly blended into asphalt, the raw material must have a viscosity average molecular weight of 7500, although it depends on the type and amount of monomer to be grafted.
~15,000 polyethylene is preferred.

In addition, polyethylene with a molecular weight of tens of thousands or more, especially 2 to
When using polyethylene of 30,000 or more, the polyethylene may be thermally decomposed in advance to lower its molecular weight. For example, high molecular weight polyethylene is heated to 350~
Raw polyethylene suitable for the purpose of the present invention can be prepared by pyrolysis at 450'C for 1 to 30 minutes.

The methods for grafting unsaturated carboxylic acids and/or their derivatives onto these raw polyethylenes include a solution method, slurry method, or melt-kneading method in which the raw material polyethylene and unsaturated carboxylic acids and/or their derivatives are mixed in the presence of a radical reaction initiator. This is carried out by contacting at high temperature using a known method such as. When using the melt-kneading method, unsaturated carboxylic acid and/or its derivatives and a radical reaction initiator are tri-blended with a Henschel mixer or the like to raw polyethylene powder or pellets at a predetermined mixing ratio, or unsaturated carboxylic acid is added to an organic solvent. An acid and/or its derivative and a radical reaction initiator are dissolved, sprayed onto polyethylene powder or pellets, and blended using a Henschel mixer or the like. This blended polyethylene powder or pellets is put into a kneading machine such as a Banbury mixer or a double screw mixer, and at a temperature of 100 to 300°C, 0.1
The above-described modified polyethylene is obtained by melt-kneading for ~30 minutes. The amount of unsaturated carboxylic acid and/or its derivatives to be blended into the raw material polyethylene is adjusted as appropriate so that the degree of modification of the resulting modified polyethylene, that is, the acid value thereof, falls within the above-mentioned range. , usually 0.0l-101i for the raw material polyethylene
The amount of the radical reaction initiator is preferably 0.02 to 5% by weight, more preferably 0.05 to 1.0%, and the amount of the radical reaction initiator is 0.5% by weight or less based on the raw material polyethylene. , preferably 0.001 to 0.1% by weight, more preferably 0.001 to 0.1% by weight. O is used within the range of 1 to 0.05% by weight.

Examples of unsaturated carboxylic acids and derivatives thereof include unsaturated carboxylic acids such as maleic acid, fumaric acid, acrylic acid, methacrylic acid, and citraconic acid, and derivatives such as their anhydrides, esters, and amides. Among these, maleic anhydride and acrylic acid are preferred, and maleic anhydride is particularly preferred.

Further, as a radical reaction initiator, an organic peroxide, an azobis compound, or the like is used. Organic peroxides include benzoyl peroxide, acetyl peroxide,
Dimomonobutyl peroxide, L-butyl peroxylaurate, dicumyl peroxide, α, α'-bis(t-butylperoxyisopropyl)benzene, 2.
5-dimethyl-2,5-di(t-butylperoxy)hexane-3,2,5-dimethyl-2,5-di(butylperoxy)hexane, L-butylperoxybenzoate, n-butyl -4,4-bis(L-butylperoxy)pivalate, octanoyl peroxide, p-
Examples include menthane hydroperoxide. Also,
Azobis compounds include azobisisobutyronitrile,
Examples thereof include 2.2'-azobis(2,4,4-)rismethylvaleronitrile) and 2.2'-azobis(2-cyclopropylpropionitrile).

Another modification method is to graft-modify polyethylene with an unsaturated carboxylic acid and/or its derivative by the method described above, and then thermally or oxidatively decompose it, for example, converting high-molecular-weight polyethylene to unsaturated carboxylic acid and/or its derivatives. Examples include thermal decomposition at 350 to 450°C for 1 to 30 minutes in an active gas atmosphere or oxidative decomposition at 150 to 200°C for 1 to 30 minutes in an oxidizing atmosphere.

Another modification method is to introduce carboxyl groups by oxidatively decomposing polyethylene with a molecular weight higher than that in an oxidizing atmosphere. and use it. Oxidative decomposition is carried out by heating polyethylene at 150 to 200 ml while stirring and blowing oxygen or an oxygen-containing gas such as air into the polyethylene.
This is carried out by oxidizing at a temperature of 0.000C for 1 to 30 minutes.

Regardless of the modification method, raw material polyethylene, etc.
It is necessary to introduce a carboxyl group and/or a group derived from a carboxyl group, i.e., an ester, an acid amide, etc., and furthermore, a portion of the carbonyl group or hydroxyl group may be present in the modified polyethylene. etc. are adjusted so that the acid value of the resulting modified polyethylene is usually in the range of 0.1-100, preferably 0.2-10. If the acid value is 100 or more, adhesion is improved, but it is not preferable in terms of suppressing temperature sensitivity in high temperature ranges and durability. On the other hand, if the acid value is 0.1 or less, water resistance, adhesion, and peeling resistance are poor. Sexual improvement is not sufficient.

Examples of surfactants include anionic surfactants such as fatty acid salts, sulfate ester salts, sulfonate salts, and phosphate ester salts; cationic surfactants mainly containing quaternary ammonium salts;
Amphoteric surfactants such as alkyl betaine; polyoxyethylene alkyl ether, polyoxyethylene alkylphenol ether, polyoxyethylene styrenated phenol eniter, polyoxyethylene alkylamino ether, polyethylene glycol fatty acid ester, polyoxyethylene polypropylene glycol, glycerin fatty acid It lowers the viscosity of liquid media containing esters, sorbitan fatty acid esters, phalt, modified polyethylene, lubricating oils, etc., and also increases the affinity and storage stability between asphalt and aggregate. A cationic surfactant or a nonionic surfactant is preferably used depending on the polarity with the aggregate and modified polyethylene.

As the lubricating oil, an ordinary plate having a specific gravity of 0.82 to 0.98 and a flash point of about 150 to 300°C is used.

Specifically, machine oil, turbine oil, axle oil, diesel engine oil, motor oil, process oil, and mixtures thereof are used.

In the present invention, the above-mentioned calcium carbonate or magnesium carbonate aggregate, straight asphalt with a penetration degree of 40 to 100, modified polyethylene with a melting point of 90 to 120°C having a carboxyl group or a group derived from a carboxyl group, and an interface An asphalt cold-cure mix is prepared by mixing an activator and a lubricating oil. The mixing ratio of each of the above components is selected, for example, from the following range.

The total amount of carbonate aggregate and straight asphalt is 10
If 0 parts by weight, the aggregate is 85 to 98% by weight, preferably 90 to 96% by weight, and the asphalt is 2 to 15% by weight.
, preferably from 4 to 10% by weight.

The amount of other additives used depends on the nature of the aggregate and asphalt.
Depending on the shape, blending ratio, etc., and the relationship between other additives, they are selected appropriately to suit each case. Polyethylene is 3 to 20% by weight, preferably 5 to 10% by weight, surfactant is 2 to 10% by weight,
Preferably 3 to 6% by weight, and more preferably 5 to 40% by weight of lubricant.
, preferably from 10 to 30% by weight.

In addition, when mixing the above components, rubber-like substances such as 5BR-NBR and BR, polymer modifiers such as thermosetting resins such as epoxy resin, calcium hydroxide, and metals such as manganese, cobalt, nickel, and iron, etc. It is also possible to add additional additives.

The order of mixing the above components is not particularly limited, but is appropriately selected in consideration of the melting point of asphalt, the melting point of modified polyethylene, the flammability of lubricating oil, etc. For example, aggregate heated to 120 to 200°C is weighed and put into a mixer, and a molten liquid mixture containing the four components of straight asphalt, modified polyethylene, surfactant, and lubricating oil is added dropwise to it while stirring. Alternatively, it can be supplied in atomized form. Considering the blending ratio, the straight asphalt component and the other three component mixture can be divided and supplied.

The flash point of lubricating oil is 150 to 300°C, which is sufficiently high that there is almost no risk of ignition when mixing.1) However, when using a lubricating oil with a lower flash point, first, straight asphalt, aggregate, etc. A molten liquid mixture containing modified polyethylene and a surfactant is added, and the resulting mixture is once discharged to another mixer until the temperature of the mixture is 140°C.
Preferably, a predetermined amount of lubricating oil may be added after the mixture is cooled down to below 100°C.

The mixture obtained by blending each predetermined component is cooled to around room temperature by natural cooling or forced cooling in a mixer, and then discharged from the mixer and packed into polyethylene bags (20 kg each).
, packaged in 30 kg etc. and commercialized.

(Examples) The present invention will be explained in more detail by Examples below, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Example 1 (A) Production of modified polyethylene High-pressure low density polyethylene with a viscosity average molecular weight of 40,000 and a melting point of 105°C was thermally decomposed at 400°C for 10 minutes under a nitrogen cloud atmosphere to obtain raw polyethylene. . 5000 ppm of maleic anhydride and α, α′-
Blend 250 ppm of bis(tert-butylperoxyisopropyl)benzene, heat mix at 250°C,
Modified polyethylene grafted with maleic acid was obtained. The resulting modified polyethylene had a melt viscosity of 18,500 cps at 160°C, an acid value of 5.0, a melting point of 110°C, and a viscosity average molecular weight of 12,000.

Bar (B) Manufacture of alfalt room temperature curing composite material Penetration 60
/80 straight asphalt 100 parts by weight, (A)
8 parts by weight of the modified polyethylene obtained in step 1, 20 parts by weight of lubricating oil (motor oil), and 4 parts by weight of nonionic surfactant (polyoxyethylene lauryl amino ether) were mixed at once, and the mixture was further heated to 150°C and stirred to form a uniform mixture. A molten liquid mixture was obtained.

3000 parts by weight of dolomite crushed to an average particle size of 5 am was heated to 150°C and charged into an asphalt mixer,
While stirring, 132 parts by weight of the above molten liquid mixture was added and mixed in several portions. Thereafter, it was cooled to room temperature to obtain an asphalt mixture.

(C) Peeling test for physical property measurement of asphalt mixture is 0110 when the peeling area percentage is 5% or less.
% or more was indicated as ×. In addition, storage stability was evaluated by the following method. That is, the asphalt mixture is packed into 30 kg bags and stored in 10 stacks.

After a certain period of time, the bottom stack of 10 bags is opened and used for on-site construction.

The difficulty of leveling is evaluated using the following index.

Example 2 Maleic anhydride 5000 ppm and α,
250 ppm of α'-bis(tert-butylperoxyisopropyl)benzene was blended and mixed under heating at 250°C to obtain modified polyethylene grafted with maleic acid. Furthermore, this was thermally decomposed at 400° C. for 15 minutes under a nitrogen atmosphere. The resulting modified polyethylene had a melt viscosity of 11,500 cps at 160°C, an acid value of 3.0, and a melting point of 10.
The viscosity average molecular weight was 10,500 at 5°C.

Using this modified polyethylene, an asphalt cold-curing composite material was prepared in the same manner as in Example 1, and the physical properties were measured in the same manner to obtain the results shown in Table 1.

Example 3 An asphalt mixture was prepared in the same manner as in Example 1 except that the blended amounts of each component were changed as shown in Table 1, and the physical properties were similarly measured to obtain the results shown in Table 1. Ta.

Example 4 An asphalt mixture was prepared in the same manner as in Example 1 except that limestone was used instead of the dolomite used in Example 1, and the physical properties were measured in the same manner to obtain the results shown in Table 1.

Example 5 Ethylene-vinyl acetate copolymer (vinyl acetate content 15
Weight%, melt flow rate 2g/10min, density 0.9
33 g/cd) as a raw material, maleic anhydride was subjected to a graft reaction in the same manner as in Example 1 to obtain modified polyethylene. Using this, an asphalt cold-curing composite material was prepared in the same manner as in Example 1, and the physical properties were similarly measured to obtain the results shown in Table 1.

Comparative Example 1 An asphalt mixture was produced in the same manner as in Example 1 except that the addition of a surfactant was omitted. Its physical properties are shown in Table 2.

Comparative Example 2 An asphalt mixture was produced in the same manner as in Example 1 except that the addition of modified polyethylene was omitted.

Its physical properties are shown in Table 2.

Comparative Example 3 Asphalt polymerization was carried out in the same manner as in Example 1, except that 8 parts by weight of ethylene-vinyl acetate copolymer (melt index 1.5 g 710 minutes, vinyl acetate content 20 mol%) was used instead of 8 parts by weight of modified polyethylene. manufactured the material. Its physical properties are shown in Table 2.

Comparative Example 4 A room temperature product made of crushed limestone with a grain size of 5 to 13 mm as aggregate and asphalt emulsion (soft straight asphalt with a penetration rate of 20/40 dispersed in water using an emulsifier). The physical properties of the hardened asphald composite material (commercially available) were measured, and the results shown in Table 2 were obtained.

2 (Effects of the Invention) The asphalt room-temperature curing material of the present invention differs from heating material that is applied in a heated state, and the room-temperature material taken out from the packaging is laid on the area to be paved, repaired, etc. Then, by tamping it, it can be opened and used immediately without the need for special curing treatment. In other words, due to the interaction of modified polyethylene, surfactant, and lubricating oil, asphalt is evenly coated around the calcium carbonate or magnesium carbonate aggregate with good adhesion, and has excellent fluidity and workability even at room temperature, and is storage stable. It also has excellent sex. After construction, it is thought that the asphalt containing modified polyethylene forms a kind of network, and that, combined with the volatilization of some of the lubricating oil, the carbonate-based aggregates are firmly bound together. It also has excellent productivity and storage stability.

Paved roads constructed with the asphalt cold-curing mixture of the present invention have excellent water resistance and durability, as well as excellent load strength and marshall stiffness.

Claims (2)

[Claims] (1) Calcium carbonate or magnesium carbonate aggregate,
An asphalt cold-curing composite material consisting of straight asphalt with a penetration of 40 to 100, a modified polyethylene having a carboxyl group or a group derived from a carboxyl group and a melting point of 90 to 120°C, a surfactant, and a lubricating oil. (2) Straight asphalt, modified polyethylene, surfactant, and lubricating oil are added to the aggregate heated to 120 to 200°C with stirring, and then cooled to room temperature. A method for producing asphalt room-temperature-curing composite material.