JP4657691B2 - Stabilizer for asphalt emulsion composition - Google Patents

Description

  The present invention relates to a stabilizer for an asphalt emulsion composition and an asphalt emulsion composition using the same.

  From the viewpoint of storage stability and mechanical stability of asphalt emulsion composition, as an emulsifier for oil-in-water asphalt emulsion, anionic emulsifier, cationic emulsifier, amphoteric emulsifier, nonionic emulsifier Are used according to their respective purposes.

  Among these, nonionic emulsifiers are preferably used when inorganic substances such as cement are mixed because they have good chemical stability.

Regarding such nonionic emulsifiers, for example, Patent Document 1 discloses rosins with a specific alkylene oxide added, and Patent Document 2 discloses a long-chain alcohol with an alkylene oxide added, from the viewpoint of a stabilizer for asphalt emulsions. Patent Document 3 discloses a stabilizer composed of a polyoxyethylene addition compound.
JP-A-11-116816 JP2000-103968A JP 2002-138201 A

  However, an asphalt emulsion composition using a nonionic emulsifier cannot be said to have sufficient storage stability at high temperatures, and there is room for further improvement in mechanical stability during construction.

  The present invention relates to a stabilizer for an asphalt emulsion composition for improving the storage stability at high temperature of the asphalt emulsion composition and the mechanical stability during construction, and the storage stability at high temperature and the mechanical stability during construction. It is an object of the present invention to provide an asphalt emulsion composition excellent in stability.

  The present invention relates to a stabilizer for asphalt emulsion compositions containing a cationic polymer (A) containing quaternary nitrogen.

  The present invention also relates to an asphalt emulsion composition comprising asphalt, a nonionic emulsifier, water and the stabilizer for the asphalt emulsion composition of the present invention.

  The stabilizer for an asphalt emulsion composition of the present invention can improve the storage stability of the asphalt emulsion composition at a high temperature and the mechanical stability during construction, and by using this, the storage stability at a high temperature can be improved. Asphalt emulsion compositions having excellent properties and mechanical stability during construction can be provided.

  The present inventors examined the asphalt emulsion composition from the viewpoints of storage stability and mechanical stability during construction. According to the techniques disclosed in Patent Documents 1 to 3, the storage stability at high temperatures, or When the asphalt emulsion is transported with a gear pump or the like, it has been found that the mechanical stability that the asphalt particles are fused and aggregated due to frictional shearing or the like and further gelation is not sufficiently ensured.

  Therefore, the present inventors examined from the viewpoint of an auxiliary agent for improving the storage stability and mechanical stability of the asphalt emulsion composition, and that the specific cationic polymer has an extremely excellent improvement effect. The headline and the present invention have been completed. This effect is remarkably exhibited also in an asphalt emulsion composition using a highly versatile nonionic emulsifier.

<Cationic polymer (A)>
As the cationic polymer (A) used in the present invention, a quaternary nitrogen, a polyoxyalkylene group comprising an alkyl group having 1 to 22 carbon atoms, an oxyalkylene group having 1 to 8 carbon atoms, and Formula (1)

Wherein R _{1 to} R ₅ may be the same or different and each represents a hydrogen atom or an alkyl or alkenyl group having 1 to 22 carbon atoms, and Z is —O— or —NY—. (Y is a hydrogen atom or a C1-C10 alkyl group), and n is a number of 1-10. However, R ₁ and R ₃ may be incorporated into the polymer structure, in which case R ₁ and R ₃ are not present. A polymer to which a group selected from the above is bonded is preferable.

  Examples of the counter ion of the cationic polymer include anionic ions such as halogen ions, sulfate ions, alkyl sulfate ions, phosphate ions, and organic acid ions. When used for concrete, anionic ions other than halogen ions are preferred from the viewpoint of preventing corrosion of reinforcing bars.

  As the cationic polymer (A), a polymer in which the quaternary nitrogen is derived from a diallyldimethylammonium salt is also suitable.

  The cationic polymer (A) includes a (meth) acrylic acid monomer having a cationic group, a styrene monomer having a cationic group, a vinylpyridine monomer, a vinylimidazoline monomer, and diallyldialkyl. A polymer having a structure derived from a monomer selected from the group consisting of amine monomers is preferred.

Specific examples of the cationic polymer (A) include poly (diallyldimethylammonium salt), polymethacryloyloxyethyldimethylethylammonium salt, polymethacrylamidopropyltrimethylammonium salt, polytrimethylallylammonium salt, cationized polysaccharide derivatives such as Cationic starch, cationized cellulose, cationized hydroxyethyl cellulose and the like, which may be obtained by polymerizing a monomer having a quaternary salt structure, or may be obtained by quaternizing the corresponding polymer with a quaternizing agent. . These may not be homopolymers, and may be a copolymer with a copolymerizable monomer as required. Specifically, diallyldimethylammonium salt-SO ₂ copolymer, diallyldimethylammonium salt-acrylamide copolymer, diallyldimethylammonium salt-acrylic acid-acrylamide copolymer, methacryloyloxyethyldimethylethylammonium salt-vinylpyrrolidone copolymer, methacrylamidopropyl And trimethylammonium salt-vinyl pyrrolidone copolymer. These may contain unreacted monomers, by-products, polymers of different cationization densities. These can be used in combination of two or more.

  Among the above, poly (diallyldimethylammonium salt), polymethacryloyloxyethyldimethylethylammonium salt, polymethacrylamidopropyltrimethylammonium salt, methacryloyloxyethyldimethylethylammonium salt-vinylpyrrolidone copolymer, and methacrylamidepropyltrimethylammonium salt-vinyl Cationic polymers selected from pyrrolidone copolymers are preferred.

  Compounds derived from the group represented by the general formula (1) include methacryloyloxyethyltrimethylammonium salt, methacryloyloxyethyldimethylethylammonium salt, methacryloyloxypropyltrimethylammonium salt, methacryloyloxypropyldimethylethylammonium salt, methacrylamide Ethyl trimethylammonium salt, methacrylamidoethyldimethylethylammonium salt, methacrylamideamidopropyltrimethylammonium salt, methacrylamidopropyldimethylethylammonium salt, acryloyloxyethyltrimethylammonium salt, acryloyloxyethyldimethylethylammonium salt, acryloyloxypropyltrimethylammonium salt, Acryloyloxypropyldimethyl Examples include tillammonium salt, acrylamidoethyltrimethylammonium salt, acrylamidoethyldimethylethylammonium salt, acrylamidopropyltrimethylammonium salt, acrylamidopropyldimethylethylammonium salt, and the like, and these are preferably alkyl sulfates, especially ethyl sulfate and methyl sulfate. .

The weight average molecular weight of the cationic polymer (A) is preferably 1,000 or more, more preferably 1,000 to 3,000,000, particularly preferably 5,000 to 1,500,000. This weight average molecular weight is measured by gel permeation chromatography under the following conditions.
Column: α-M (manufactured by Tosoh Corp.) 2 linked eluent: 0.15 mol / L Na sulfate, 1% acetic acid aqueous solution Flow rate: 1.0 mL / min
Temperature: 40 ° C
Detector: RI
Pullulan is used as molecular weight standard

  The cationic polymer (A) has a cationization density of 0.5 to 10 meq / g, more preferably 1 to 9 meq / g, and particularly preferably 3 to 8 meq / g. The cationization density can be measured by the method of Examples described later.

<Asphalt emulsion composition>
The stabilizer of the present invention is particularly preferably used in combination with a nonionic emulsifier as an emulsifier because the improvement in chemical stability of the asphalt emulsion composition is remarkable. Depending on the purpose, an anionic emulsifier, a cationic emulsifier, and an amphoteric emulsifier can be used in combination.

  The asphalt used in the production of the asphalt emulsion composition of the present invention is a residual oil (solid or semi-solid residue) obtained by distilling crude oil and collecting naphtha, gasoline, kerosene, light oil, etc., straight asphalt, Examples include cutback asphalt, blown asphalt, semi-blown asphalt, modified asphalt, natural bitumen, and recycled asphalt.

  The amount of asphalt in the asphalt emulsion composition is preferably 40 to 80% by weight, and the amount of water is preferably 20 to 60% by weight.

<Nonionic emulsifier>
Nonionic emulsifiers include (1) sorbitan esters, alkylene oxide adducts of sorbitan esters, (2) ethylene oxide adducts of long-chain alcohols such as palm oil reduced alcohol, beef tallow reduced alcohol, Ziegler alcohol, oxo alcohol, secondary alcohol, etc. (3) Alkylphenol ethylene oxide adducts, (4) alkyl glucosides, (5) triblock polymers obtained by adding alkylene oxides to long-chain alcohols, and (6) polypropylene glycol ethylene oxide adducts. From the viewpoints of storage stability and cement mixing properties, the average addition molar amount of ethylene oxide of the long-chain alcohol (2) is preferably 10 to 200 mol, and more preferably 30 to 90 mol. As (2), what added 30-200 mol of ethylene oxide on average to C12-16 alcohol is mentioned. In the triblock type polymer in which alkylene oxide is added to the long chain alcohol of (5), it is preferable that the end of the polymer chain is added with ethylene oxide. The polypropylene glycol ethylene oxide adduct (6) is preferably a polymer having a weight average molecular weight of 5000 to 10,000 and a total molecular weight of oxyethylene groups accounting for 75% by weight or more of the total molecular weight of oxyethylene groups and oxypropylene groups.

  Examples of the anionic emulsifier include fatty acids, alkyl sulfates, alkyl ether sulfates, alkylbenzene sulfonic acids, lignin sulfonic acids, alkyl phosphoric acids, and salts thereof.

  Examples of the cationic emulsifier include alkylamines, alkylpolyamines, alkylamidoamines, their ethylene oxide or propylene oxide adducts, alkylimidazoline mineral acids or lower carboxylates, and quaternary ammonium salts.

  Examples of the amphoteric emulsifier include betaine acetate, amide betaine, aminated lignin, sulfobetaine, imidazolium betaine, and amine oxide.

  In order to improve emulsifiability, an inorganic salt can be used in combination, and examples of the inorganic salt include sodium chloride, potassium chloride, calcium chloride, and aluminum chloride.

  In the asphalt emulsion composition of the present invention, the content of the stabilizer of the present invention (in terms of solid content) is preferably 0.001 to 0.5% by weight, from the viewpoint of storage stability after production of the asphalt emulsion composition, 0.01 to 0.05% by weight is particularly preferred.

  Further, the stabilizer (I) and the nonionic emulsifier (B) of the present invention are (I) / (B) = 0.15 / 100 to 42/100, more preferably 0.8 / 100 to 4.2 / 100 The weight ratio is preferably used.

  The asphalt emulsion composition of the present invention is preferably an asphalt emulsion (oil-in-water emulsion) containing water, and can be produced according to a usual method. In the asphalt emulsion composition of the present invention, the total concentration (in terms of solid content) of the stabilizer of the present invention and the nonionic emulsifier is preferably 1 to 5% by weight from the viewpoint of producing the asphalt emulsion composition. . Also in this case, it is preferable to satisfy the above weight ratio.

  The production method of the asphalt emulsion composition may be any method that is generally used. For example, methods such as a mechanical elastic emulsification method and a phase transition method can be used. A general emulsifier can be used for the production of the asphalt emulsion composition of the present invention, and a colloid mill, a Hallel homogenizer, a line mixer, etc. can be used depending on the purpose of use.

  The asphalt emulsion composition of the present invention can be suitably used when an inorganic material such as cement is mixed. In that case, as the cement, those defined in JIS R 5210, 5211, 5212, 5213 can be used.

  Both 60 parts by weight of molten asphalt obtained by heating and melting straight asphalt with a penetration of 80 to 100 at 145 ° C. and 40 parts by weight of an emulsified solution in which emulsifier and stabilizer are dissolved in 55 ° C. warm water are colloidal. An asphalt emulsion was produced through a mill. The emulsifier is dissolved in the above emulsion so that the final emulsion composition is 1.2% by weight (solid content) and the stabilizer is 0.02% by weight (solid content) in the final emulsion composition. Used (except for Comparative Example 2). The stabilizers in Table 1 and the emulsifiers in Table 2 were used in the combinations shown in Table 3. In Table 3, the weight% of the stabilizer and the emulsifier is the concentration in terms of solid content in the final emulsion composition.

  The following tests were performed on the obtained asphalt emulsion composition. The results are shown in Table 3.

Asphalt concentration: Measured according to “Evaporation residue” of JIS K 2280.

-Fluid residue: Measured based on the measurement method of the sieve residue shown in ASTM D 2397. The sieve residue is an asphalt solid contained in the asphalt emulsion, and 0.1% or less is a practically acceptable level, and the smaller the value, the better.

Storage stability: Based on JIS K 2280 “Storage stability”, the product was measured after being left in a constant temperature room at 35 ° C. for 5 days. The lower the numerical value, the higher the storage stability of the emulsion.

Mechanical stability: 1000 g of asphalt emulsion composition is circulated for 2 minutes using a gear pump (RP-PUMP type manufactured by DAIDO METAL Co.) at a discharge speed of 5000 ml / 1 minute. The asphalt emulsion after circulation for 2 minutes was passed through a 1 mm sieve and the amount of asphalt solids remaining on the sieve was measured. The lower the numerical value, the better the mechanical stability because there is no asphalt aggregation due to frictional shear of the gear pump.

  In the table, EO is ethylene oxide, and the number after () is the average number of added moles (the same applies hereinafter).

The cationization density measurement (colloidal titration) of the cationic polymer was performed as follows. First, a cationic polymer (which may be pure or in solution) is dissolved in water adjusted to pH 3.0 with phosphoric acid. Toluidine blue indicator was added, titrated with a 1 / 400N polyvinyl potassium sulfate solution, and the color change was determined as the end point. The cationization density was determined by the following calculation formula.
Cationization density (meq / g) = 1/400 × f × (mL) / 1000 × 1000 × 1 / [(g) × (%) / 100]
f: Factor of 1 / 400N polyvinyl potassium sulfate solution
(mL): dripping amount of polyvinyl potassium sulfate solution
(g): Sample amount
(%): Sample concentration

Claims (4)

A stabilizer for an asphalt emulsion composition containing a cationic polymer (A) containing quaternary nitrogen,
For the asphalt emulsion composition, the cationic polymer (A) containing quaternary nitrogen is a cationic polymer selected from cationic polymers containing quaternary nitrogen derived from diallyldimethylammonium salt and cationized hydroxyethyl cellulose . Stabilizer.   The stabilizer for asphalt emulsion compositions according to claim 1, wherein the cationic polymer (A) has a weight average molecular weight of 1000 or more. An asphalt emulsion composition comprising asphalt, a nonionic emulsifier, water, and the stabilizer for asphalt emulsion compositions according to claim 1 or 2.   The asphalt emulsion composition according to claim 3, comprising 0.1 to 30 parts by weight of the cationic polymer (A) with respect to 100 parts by weight of the nonionic emulsifier.