JPH02292368A - Asphalt modifier - Google Patents

Abstract

PURPOSE:To form an asphalt modifier with a large grasping force and adhesive force to an aggregate, soluble in an asphalt in a short time and with good long-term stability by emulsifying and dispersing a thermoplastic elastomer in the presence of a specified surface active agent. CONSTITUTION:A water-based emulsified dispersion is formed by emulsifying and dispersing a thermoplastic elastomer in the presence of an emulsifying and dispersing agent wherein 10wt.% or less polyalkylene oxide group-contg. anionic surface active agent based on this elastomer is a main component with a mean particle diameter of 5mum or smaller. As said emulsifying and dispersing agent, an anionic surface active agent of formula I (wherein R is an active hydrogen compd. residue; (n) is an integer of 2 to 3; (m) is an integer of 1 to 10; (l) is an integer of 1 to 2; A is an alkali metal salt, ammonium salt or an amine salt of a compd. selected from sulfonic acid, sulfate, phosphate and acetic acid) and if necessary, a nonionic surface active agent of formula II (wherein R' is an active hydrogen compd. residue; (p) is an integer of 2 to 3; (q) is an integer of 0 to 20) are used at a ratio of I/II of 100/0-60/40.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an asphalt modifier that imparts suitable properties to asphalt for road paving, and more particularly, it relates to an asphalt modifier that imparts properties suitable for asphalt for road paving, and more particularly, it relates to an asphalt modifier that imparts properties suitable for asphalt for road paving. The present invention relates to an asphalt modifier comprising an aqueous emulsified dispersion of a thermoplastic elastomer that can be dissolved in asphalt in a short time.

[Prior art] In recent years, by adding polymeric materials such as rubber and resin (including elastomers, the same applies hereinafter) to asphalt,
Modified asphalt with improved viscosity at 60°C, toughness, tenancy, temperature sensitivity, etc. has been used for the purpose of improving flow resistance, abrasion resistance, etc. of pavement, and its effects have been confirmed. The following are known as conventional modifiers or modification methods.

(1) There is an existing method of mixing polymeric materials such as rubber and resin with asphalt. For example, (1) a method in which the rubber or resin is dissolved in an organic solvent, and then added little by little to heated and melted sulfate while stirring, and the solvent is evaporated at the same time as the dissolution is allowed to occur. A method in which solid or molten resin is kneaded with non-volatile heavy oil, cut into pieces, and then mixed and dissolved in heated and melted asphalt. ■ Solid or molten resin is stirred and added little by little to heated and melted asphalt. There are methods such as dissolving it.

(2) A method using an aqueous emulsion obtained by emulsifying and dispersing a rubber or thermoplastic block copolymer obtained by solution polymerization as a modifier has also been attempted, but this method is described in JP-A-61-23610. However, it has not been put into practical use due to the following problems.

(3) There is a method in which an aqueous emulsified dispersion of rubber is used as a modifier.

[The problem that the invention seeks to solve] The prior art as described above has the following problems.

In the case of (1) above, each method requires a complicated process and has the disadvantage that resins and rubbers deteriorate because they are exposed to high temperatures for a long time during the process.

In addition, in methods that use organic solvents, organic gases are generated during mixture production due to vaporization of the organic solvents contained, creating a risk of ignition, and gases generated during road paving work can cause harm to the human body. There are operational problems such as, and when the organic solvent does not completely evaporate, the effect of modifying asphalt by the polymeric material is hindered.

In the case of (2), the problems caused by organic solvents in (1) can be solved by using an aqueous emulsion, and high workability and safety can be ensured. Since it is difficult to make the combined particle size small and uniform, the dispersion stability is poor, and therefore the emulsion cannot be maintained in a stable state for a long period of time. In addition, a large amount of emulsifying and dispersing agent is required to achieve sufficient emulsification, which greatly impairs the characteristics originally possessed by rubber, thermoplastic block copolymers, etc., and their modification is insufficient. The problem is that it cannot be achieved.

In the case of (3), since an aqueous emulsion dispersion is used, (2)
High workability and safety can be ensured as in the case of . Furthermore, for example, the content of the emulsifying dispersant in the aqueous emulsion of rubber latex and thermoplastic elastomer obtained by emulsion polymerization is usually 1 to 3% by weight, and the particle size of the emulsion is as small as 1 μm, resulting in poor dispersion stability. Because of its excellent properties, it is advantageous for modifying asphalt, and rubber-based products have traditionally been used in plant mixes.

However, an aqueous emulsion dispersion using a thermoplastic elastomer has not yet been put into practical use.

[Means for Solving the Problems] The present inventors have overcome the problems in the above-mentioned existing methods for producing asphalt mixtures and methods using thermoplastic elastomers obtained by solution polymerization, and can mix them into asphalt in a short time. As a result of intensive research into an aqueous emulsion dispersion that dissolves, is harmless, does not impair the original properties of thermoplastic elastomers, and has good long-term stability.
We have arrived at the present invention.

That is, the present invention provides a thermoplastic elastomer in which the average particle size of the thermoplastic elastomer is reduced to 5 μm or less in the presence of an emulsifying dispersant whose main component is an anionic surfactant containing a polyalkylene oxide group in an amount of 10% by weight or less based on the elastomer. This is an asphalt modifier made of an aqueous emulsified dispersion.

[Structure and operation of the invention] Examples of the thermoplastic elastomer used in the present invention include ethylene-vinyl acetate (vinyl acetate, hereinafter the same) copolymer (BVA), styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), styrene-ethylene-butylene, styrene block copolymer (S
BBS), and these can be used alone or in combination of two or more.

The emulsifying dispersant of the present invention has the general formula R [(C,,H..0). }. A --゜゛［
I] and the general formula R' {Cp8.0} qH -...
-・[II] [R and R' are residues of a compound containing an active hydrogen atom, usually having 8 to 22 hydrocarbons, having a ring structure, straight or branched, or having a sulfuric acid atom. ,
Atoms other than carbon, such as nitrogen and oxygen, may be contained in the carbon matrix. ] An anionic surfactant [I] represented by [I] and a nonionic surfactant [■] are used if necessary.

Among these, preferred are monohydric alcohols having 10 to 13 carbon atoms, compounds having 20 to 21 carbon atoms, and specifically, for example, the terminal -DH group, -SH group, -N
il. group, -NH group, -C-OH group, etc., from which the H group is removed.

(1) In the case of alcohol: 1. Synthetic primary alcohols such as 2-ethylhexanol, n-tanol, decanol, dodecanol, tetradecanol, hexadecanol, octadecanol, alfol, dovanol, tercitol S1 Residues obtained by removing active hydrogen from synthetic secondary alcohols such as softanol and oxo alcohol, benzyl alcohol, and octylphenol and nonylphenol as phenol.

(2) For amines: Residues obtained by removing active hydrogen from higher amines such as laurylamine, laurylmethylamine, and dioleylamine.

(3) In the case of thiol: Residues obtained by removing active hydrogen from lauryl thiol, layl thiol, etc.

(4) For carboxylic acids: Residues obtained by removing active hydrogen from lauric acid, myristic acid, palmitic acid, oleic acid, stearic acid, behenic acid, etc.

Among the anion salts represented by A in general formula [I], the anion component is sulfonic acid, sulfate ester, phosphate ester, or acetic acid, and the counter ion is usually an alkali metal (for example, Li, Na, κ), Lower amines such as ammonia, methylamine, ethylamine, monoethanolamine, diethanolamine and triethanolamine. Preferred among these are sulfate esters and alkali metal salts of acetic acid.

In general formulas [I] and [II], n and p are integers indicating the number of carbon atoms in the oxyalkylene group, and examples thereof include an oxyethylene group and an oxypropylene group. The oxyethylene group and the oxypropylene group may be bonded alone, in blocks, or randomly. Regarding the degree of polymerization of the oxyalkylene group, m is usually an integer of 1 to 10, preferably 2 to 10.
It is an integer of 4. q is usually an integer of 0 to 20, preferably 3 to 10. L is A is a sulfonate,
In the case of sulfate ester salt and acetate salt, L=1, and A
When is a phosphate ester salt, t is an integer of 1 to 2.

An anionic surfactant represented by the general formula [I] and a general formula [
The usage ratio (weight ratio) of the nonionic surfactant represented by [II] is usually 100/0 to 60/40, preferably 1
00/0 to 80/20, more preferably 100/0 to 9
It is 2/8. If the ratio exceeds 60/40, the resulting aqueous dispersion will have a large particle size and poor emulsion stability.

Anionic surfactants represented by general formula [I] and [I
It is important to adjust the total amount of the nonionic surfactant represented by I] to usually 10% by weight or less, preferably 1 to 7% by weight, based on the thermoplastic elastomer. 10% by weight
If it exceeds this value, the original properties of the thermoplastic elastomer that modifies asphalt, such as the effect of improving toughness and tenacity, will be impaired, and as a result, it will not be possible to modify asphalt as desired.

In the process of emulsifying and dispersing a thermoplastic elastomer, an organic solvent can be used for the purpose of lowering the softening point of the elastomer and making emulsifying and dispersing easier. Examples of the organic solvent include those capable of dissolving the thermoplastic elastomer, such as toluene, xylene, n-hexane, and cyclohexane. The amount of these organic solvents used is
The amount is 50 to 300% by weight, preferably 100 to 200% by weight, based on the thermoplastic elastomer. After emulsification and dispersion, these organic solvents have a content of 0.0% relative to the aqueous emulsion dispersion. 4
It is removed from the system in an amount of less than 0.1% by weight, preferably less than 0.1% by weight. The content of these organic solvents contained in the aqueous emulsion dispersion is 0. If it is 4% by weight or less, there is no risk of organic gas igniting due to vaporization of the organic solvent contained during the production of the mixture with asphalt, and the harm to the human body caused by organic gas during road paving work is minimized. It can be suppressed and there is no problem in operation. It is also possible to prevent the adverse effects of solvents on the paving effect.

The average particle diameter of the aqueous emulsified dispersion of thermoplastic elastomer used in the present invention is 5 μr! If this is the case, the dispersion stability of the resulting aqueous emulsified dispersion decreases, causing separation or aggregation, which poses a practical problem. Dispersion stability can be improved by setting the average particle diameter to 5 μm or less, which corresponds approximately to the range in which particles can move due to thermal motion.

Furthermore, the aqueous emulsion dispersion of the thermoplastic elastomer of the present invention may contain or be used in combination with an antioxidant, an ultraviolet absorber, a preservative and fungicide, an antifoaming agent, or a pigment.

[Example] Hereinafter, the present invention will be further explained with reference to Examples, but the present invention is not limited thereto. In addition, % in the examples
indicates weight 1%.

Example 1 500 g of JSR SIS 5000 (styrene-isoprene block copolymer manufactured by Japan Synthetic Rubber ■) and 750 g of toluene were placed in a container equipped with a paddle-type low-speed stirrer, condenser, and aftercooler, and the mixture was stirred for 80 minutes while stirring was stopped. Raise the temperature to ~90℃, JSR SIS 5
000 was dissolved in toluene. After dissolving, polyoxyethylene nonylphenol ether sulfate ester soda salt (
Add 25 g of dasalt (4 mole ethylene oxide adduct) and stir with a paddle-type low-speed stirrer at a circumferential speed of room/min. After dissolving,
Pour 750g of warm water (60-70℃) in 60 minutes,
0/W type emulsion, and then 60 to 70
Toluene was removed at a temperature of 720 to 640 mmHg under reduced pressure to obtain a white liquid aqueous emulsion dispersion composition having a concentration of 55% and a viscosity of 520 cps. The average particle size of this material was measured using a Microtrac particle size analyzer (manufactured by Nikkiso ■) and was 1.
5μm, and the toluene content was 0.0 by gas chromatography.
It was 8%.

Example 2 JSR SIS 5000 in Example 1 is converted to SBS
The same operation was performed except for using TR-2000C (styrene-butadiene block copolymer manufactured by Nippon Gosei Rubber ■) to obtain a white liquid aqueous emulsion dispersion composition having a concentration of 54% and a viscosity of 560 cps. The average particle size of this product is 2.5μ
m, and the toluene content was 0.10%.

Example 3 In Example 1, polyoxyethylene nonylphenol ether sulfate ester sodium salt (ethylene oxide 4 mole adduct) was replaced with polyoxyethylene dodecyl ether acetate sodium salt (ethylene oxide 3 mole adduct) 2
3.0g and polyoxyethylene nonylphenol ether (ethylene oxide 4 mole adduct) 2,0
Perform the same operation, replacing g with a concentration of 55% and a viscosity of 52.
A white liquid aqueous emulsion dispersion composition of 0 cps was obtained. The average particle diameter of this product was 1.2 μm, and the toluene content was 0.02%.

Example 4 In Example 1, the amount of polyoxyethylene nonylphenol ether sulfate ester soda salt was changed to 50 g, and the same operation was performed to obtain a concentration of 53% and a viscosity of 650 cp.
A white liquid aqueous emulsion dispersion composition of s was obtained. The average particle size of this material is 2.0 μm, and the toluene content is 0.
．． It was 0.8%.

Example 5 The same operation as in Example 4 was performed except that the polyoxyethylene nonylphenol ether sulfate ester sodium salt was replaced with polyoxyethylene dodecyl ether acetate sodium salt (3 mole ethylene oxide adduct), and the concentration was 53.
%, and a viscosity of 630 cps, a white liquid aqueous emulsion dispersion composition was obtained. The average particle diameter of this product was 1.2 μm, and the toluene content was 0.10%.

Example 6 The same operation as in Example 5 was performed except that the amount of polyoxyethylene dodecyl ether sodium acetate (3 moles of ethylene oxide adduct) was changed to 35 g, and the concentration was 54%.
A white liquid aqueous emulsion dispersion composition with a viscosity of 680 cps was obtained. The average particle diameter of this product was 1.8 μm, and the toluene content was 0.08%.

Example 7 In Example 3, the amounts of polyoxyethylene dodecyl ether sodium acetate (3 moles of ethylene oxide adduct) and polyoxyethylene nonylphenol ether (4 moles of ethylene oxide adduct) were each 20 g.
, 5g, and the same operation was performed to obtain a white liquid aqueous emulsion dispersion composition having a concentration of 53% and a viscosity of 510 cps.

The average particle diameter of this product was 3.0 μm, and the toluene content was 0.05%.

Example 8 In Example 3, the amounts of polyoxyethylene dodecyl ether sodium acetate (3 moles of ethylene oxide adduct) and polyoxyethylene nonylphenol ether (4 moles of ethylene oxide adduct) were each 15 g.
, Perform the same simulation except for 10g, and the concentration was 54%.
A white liquid aqueous emulsion dispersion composition with a viscosity of 530 cps was obtained. The average particle diameter of this product was 5.0 μm, and the toluene content was 0.90%.

Comparative Example 1 The same operation as in Example 1 was carried out except that the amount of polyoxyethylene nonylphenol ether sulfate sodium salt was changed to 75 g, and the concentration was 54% and the viscosity was 750 cp.
A white liquid aqueous emulsion dispersion composition of s was obtained. The average particle size of this product is 1.5 μm, and the toluene content is 0.
．． It was 0.8%.

Comparative Example 2 In Comparative Example 1, polyoxyethylene nonylphenol ether sulfate ester sodium salt (ethylene oxide 4 mole adduct) was replaced with polyoxyethylene dodecyl ether acetate sodium salt (ethylene oxide 3 mole adduct) 6
9.0g and 6.0g of polyoxyethylene nonylphenol ether (4 moles of ethylene oxide adduct), the same experiment was performed, and the concentration was 52% and the viscosity was 680c.
A white liquid aqueous emulsion dispersion composition of PS was obtained. The average particle diameter of this product was 1.2 μm, and the toluene content was 0.10%.

Comparative Example 3 In Example 3, polyoxyethylene dodecyl ether sodium acetate (3 moles of ethylene oxide adduct) and polyoxyethylene nonylphenol ether (4 moles of ethylene oxide adduct) were each added at 13.75%
g, and 11.25 g, and the same operation was performed to obtain a white liquid aqueous emulsion dispersion composition having a concentration of 50% and a viscosity of 420 cps. The average particle size of this product is 10.0
μm, and the toluene content was 0.35%.

Test Example 1 Regarding the aqueous emulsion dispersion compositions (Examples 1 to 8) produced by the method of the present invention and the compositions produced in Comparative Examples 1 to 3, the stability of appearance over time was measured and these compositions were ,
Straight asphalt (needleness 60-80) 10
0 parts by weight, added 3% by weight in terms of solid content, and stirred at a predetermined temperature with a stirrer (3-blade stirring blade) at 4% per minute.
Stirring was performed at 00 to 500 revolutions, and the solubility and physical properties of the mixed asphalt at that time were measured.

Also, for comparison, SIS 5000 and SBS T
Straight asphalt with and without 3% R-2000C granules was also tested. The results are shown in Tables 1, 2 and 3.

Monoray” B A1 B σ》 cN? Judgment was made visually according to the following criteria.

O: Stable ascent; F6) No separation) △: Slightly poor stability; Separated somewhat) ×: Separated into C layer with poor stability.

The modified asphalt sample preparation method described in the table was followed.

(Judgment Criteria) Visual judgment was made according to the following criteria.

◎: Completely dissolved Δ: Some insoluble matter is present ×: Too much insoluble matter [Effect of the invention] The aqueous emulsion dispersion composition of the present invention has the following effects.

As the internal cohesive force of asphalt can be increased due to its large gripping force and adhesion to aggregate, asphalt using the present invention can be used to prevent rutting, corrugation, cracking of road surfaces seen at low temperatures, or spiked tires. It is possible to effectively prevent separation phenomena caused by

In addition, the thermoplastic elastomer used in the present invention is a fine particle dispersion with low viscosity and good stability that retains its original characteristics, so it is easier to handle and has a lower It can be dissolved in a short time at the melting and mixing temperature, and the dissolution time can be significantly shortened. Therefore, it is useful not only for shortening the premix process but also for shortening the plant mix process in on-site pavement work. In addition, since it can be mixed and dissolved at low temperatures and in a short time, there is less risk of heat deterioration of the modified asphalt during mixing, and the road paving effect can be improved.

Furthermore, since the aqueous dispersion composition contains only a small amount of solvent, there is no risk of ignition due to solvent scattering, and there is no harm to the human body due to the generation of gas during the production of the mixture, which is advantageous in terms of work. Furthermore, there is no performance deterioration of the modified asphalt due to solvent content.

Patent applicant: Sannopco Co., Ltd. Nigo Shoji Co., Ltd.

Claims (1)

[Claims] 1. A thermoplastic elastomer in the presence of an emulsifying dispersant whose main component is an anionic surfactant containing a polyalkylene oxide group in an amount of 10% by weight or less based on the elastomer,
An asphalt modifier comprising an aqueous emulsified dispersion in which the average particle diameter is emulsified and dispersed to be 5 μm or less. 2. The emulsifying dispersant has the general formula R[(C_nH_2_nO)_m]-_tA...[
I ] [However, R is the active hydrogen atom-containing compound residue, n is 2
an integer of ~3, m is an integer of 1 to 10, t is an integer of 1 to 2,
A represents an alkali metal salt, ammonium salt, or amine salt of a compound selected from sulfonic acid, sulfuric acid ester, phosphoric acid ester, and acetic acid. ] and an anionic surfactant represented by the general formula R'-(C_pH_2_pO)-_qH... [II] [
However, R' is a residue of a compound containing an active hydrogen atom, and p is 2 to 3.
is an integer of 0 to 20, and q is an integer of 0 to 20. ] The asphalt modifier according to any one of claims 1 to 3, wherein the asphalt modifier comprises a nonionic surfactant represented by .