JP2001214123A - Primer composition for civil engineering and construction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a primer composition for civil engineering and construction which is excellent in adhesion of metallic materials to hydraulic inorganic substances typified by concrete and mortar. SOLUTION: This primer composition essentially contains a polymer emulsion which is prepared by the emulsion copolymerization of a (meth)acrylic ester with an unsaturated monomer having a phosphoric ester group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a primer composition containing a polymer emulsion as an essential component,
More specifically, it contains an acrylic polymer emulsion as an essential component and is useful for adhesiveness between metal materials and concrete and mortar.
The present invention relates to a primer composition suitable for a case where adhesion between a metal material and a hydraulic inorganic substance is required, such as a concrete-filled steel pipe column, a steel pipe burial method, steel fiber concrete, and anticorrosion / antifouling.

[0002]

2. Description of the Related Art Hydraulic inorganic materials such as concrete and mortar and metal materials such as reinforcing steel have been used in civil engineering and construction fields for a long time to compensate for the disadvantages of their material properties. However, the adhesion between the materials is extremely poor due to the large difference in the material properties. In view of this, a method has been devised for providing reinforcing ribs on the surface of a reinforcing bar to enhance the adhesion to a hydraulic inorganic substance by a physical method. However, even in such a method, the reinforcement and concrete are not strictly integrated with each other, and a slip occurs at the rebar-concrete interface, which leads to cracking of the concrete, or a case in which the reinforcement moves to rust. Has occurred. Further, in recent years, as the maintenance of concrete structures has become active, it has been required to improve the adhesion between the repair material and the reinforcing steel. As a general repair method, the deteriorated concrete is hung up to the vicinity of the reinforcing bar and backfilled with mortar is used as a general method. In this case, the surface of the reinforcing bar is exposed on the concrete base to which the mortar is applied, and its total area occupies 10 to 50% of the base surface. Therefore, increasing the adhesion between the reinforcing steel and the mortar is one of the important techniques for developing an excellent repair method.

[0003]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention has been developed in consideration of the following problems.
An object of the present invention is to provide a primer composition having excellent adhesion performance with a hydraulic inorganic substance represented by mortar.

[0004]

In order to achieve the above-mentioned goal,
The primer composition of the present invention is a polymer emulsion obtained by emulsion-copolymerizing an unsaturated monomer having a phosphate group and at least one unsaturated monomer mixture selected from an acrylate and a methacrylate. It is characterized by containing as an essential component. With such a configuration, the adhesion between the metal material and the hydraulic inorganic substance can be improved. It is considered that such excellent properties of the present invention are partly due to the fact that phosphate groups can be effectively chemically modified on the particle surface of the polymer emulsion.

[0005] In the above structure, the average particle diameter of the polymer emulsion is preferably 30 to 200 nm. If the average particle diameter exceeds 200 nm, the specific surface area of the polymer particles becomes small, and it becomes impossible to effectively chemically modify phosphate ester groups and the like on the surface of the polymer particles. Is remarkably increased, and it is not easy to handle during production or use. From the viewpoint of improving the fine packing property, the average particle diameter is more preferably 50 nm or more, and further preferably 150 nm or less, and further preferably 100 nm or less.

In the above structure, it is preferable to carry out emulsion polymerization using an emulsifier containing a molecule having a polyoxyalkylene group and an ethylenically unsaturated bond. By using such a reactive emulsifier, not only the polyoxyalkylene group in addition to the phosphate group but also chemically modifying the polymer particle surface, it is possible to suppress a decrease in water resistance due to the presence of a free emulsifier. it can.

[0007]

First, the unsaturated monomer used in the present invention will be described. As the unsaturated monomer having a phosphate ester group, an unsaturated phosphate ester represented by the following chemical formula (1) is preferable, and in particular, (2-hydroxyethyl) methacrylate acid phosphate, (2-hydroxyethyl) acrylate acid phosphate,
(3-Hydroxypropyl) methacrylate acid phosphate is preferred. Further, a monoester and a diester are preferably used, and a monoester is most preferred.

[0008]

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In the formula (1), X represents a hydrogen atom or a methyl group, and 1 represents 1 to 100, preferably 1 to 50, and more preferably 1 to 20. S is 1 or 2. These may be acids or salts of alkali metals, alkaline earth metals, amines and the like. The content of the unsaturated monomer having a phosphate group is preferably 0.1 to 10% by weight of the total unsaturated monomer. If it exceeds 10% by weight, the water resistance of the film may be reduced, or the cement hardening reaction may be inhibited. If the amount is less than 0.1% by weight, the adhesion performance may not be sufficiently exhibited or rust may be generated on the surface of the metal material.

The acrylate and methacrylate are not particularly limited, but alkyl acrylate and alkyl methacrylate are preferred. In this case, the alkyl group has 1 to 1 carbon atoms.
18 are preferred, and more specifically,
Methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, octyl methacrylate, 2-methacrylic acid Ethylhexyl and the like can be used.

These unsaturated monomers may be used alone or in an appropriate combination of two or more. By using these unsaturated monomers, in the present invention, a phosphate ester group is introduced on the surface of the acrylate-based polymer emulsion particles to improve the adhesion, and as described above, the phosphate ester is used. By introducing an appropriate amount of the group, it is possible to obtain the effect of alleviating the strain generated between different materials while suppressing the decrease in the water resistance of the film.
It is intended to provide a primer composition suitable for construction.

In order to improve the performance derived from the resin film, such as strength, water resistance and chemical resistance, a mixture containing a plurality of functional groups in one molecule is added to the mixture containing these unsaturated monomers. Is preferably copolymerized. As the crosslinking agent, trimethylolpropane trimethacrylate, glycidyl acrylate, glycidyl methacrylate, bisphenol A polyoxyethylene adduct diacrylate, bisphenol A polyoxyethylene adduct dimethacrylate, triallyl isocyanurate, N-
Methylol acrylamide, N-methylol methacrylamide, divinylbenzene and the like can be used, but N-methylol acrylamide, N-methylol methacrylamide or trimethylolpropane trimethacrylate is preferred. The crosslinking agent is preferably used in a range of 0.1 to 5% by weight based on the unsaturated monomer.

Further, the mixture may contain other unsaturated monomers, for example, styrenes such as styrene and α-methylstyrene, dienes such as butadiene and isoprene, and acetic acid as long as the performance of the polymer emulsion is not impaired. Vinyl esters such as vinyl and vinyl propionate,
Nitriles such as acrylonitrile and α-methylacrylonitrile may be appropriately used in combination.

Next, the emulsifier which can be used in the present invention will be described. As the emulsifier, those having a polyoxyalkylene group are preferable. For example, an anionic emulsifier such as a polyoxyalkylene alkylaryl ether sulfate salt or a nonionic emulsifier such as a polyoxyalkylene alkyl aryl ether can be used.
As the emulsifier, those having an ethylenically unsaturated bond are preferable. By using such a reactive emulsifier, it is possible to suppress a decrease in water resistance due to a free emulsifier. As the emulsifier having an ethylenically unsaturated bond, for example, an anionic or nonionic emulsifier represented by the following chemical formulas (2) and (3) can be suitably used.

[Example of anionic emulsifier]

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[Example of anionic emulsifier]

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However, in equations (2) and (3), A
Is an alkylene group having 2 or 3 carbon atoms (for example, -CH ₂
—CH ₂ — or —CH ₂ —CH (CH ₃ ) —), M ₁ is a monovalent or divalent cation, n is 0 to 100, preferably 3 to 100, more preferably 5 to 40, R ₀ Is an alkyl group, alkenyl group or aralkyl group (arylated alkyl group) having 6 to 18 carbon atoms. In the emulsifier represented by the chemical formula (2) or (3), it is preferable to use those having n of 3 or more, preferably 5 or more and having both a polyoxyalkylene group and an ethylenically unsaturated bond.

The emulsifier may be used in combination with one or more of an anionic emulsifier and a nonionic emulsifier. Specific examples of emulsifiers that can be used in combination are shown below.

[Representative example of anionic emulsifier] Polyoxyalkylene alkylaryl ether sulfonate sulfate group represented by the following chemical formula (4)

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A polyoxyalkylene alkyl ether sulfate salt represented by the following chemical formula (5):

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A polyoxyalkylene alkyl aryl ether sulfate group represented by the following chemical formula (6):

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Emulsifiers represented by the following chemical formulas (7) to (12)

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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Here, m is 0 or 1, and R ₁ has 6 carbon atoms.
To 20 alkyl groups, R ₂ is a hydrogen atom or a methyl group,
₃ is an alkyl group having 1 to 30 carbon atoms, an alkenyl group, a phenyl group having an alkyl group or an alkenyl group, or a fatty acid residue, R ₄ is a methylene group, an ethylene group or a phenylene group, and A, n and M ₁ Is the same as above.

[Representative example of nonionic emulsifier] Polyoxyalkylene alkyl aryl ether represented by the following chemical formula (13)

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A polyoxyalkylene alkyl ether represented by the following chemical formula (14)

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[0031] Here, A, n and _{R 1} are as defined above. The emulsifier used in combination is preferably an anionic emulsifier having an oxyalkylene group such as an oxyethylene group and an oxypropylene group in the molecule. The emulsifier is preferably used in the range of 0.5 to 10% by weight, more preferably 0.5 to 5% by weight, based on the unsaturated monomer. If the amount is less than 0.5% by weight, a large amount of agglomerates are generated during emulsion polymerization, and it becomes difficult to obtain a polymer emulsion of a desired size. This is because there is a risk of doing so.

Examples of the polymerization initiator include hydrogen peroxide alone, a combination of hydrogen peroxide and a carboxylic acid such as tartaric acid, citric acid and ascorbic acid, and a mixture of hydrogen peroxide with oxalic acid, sulfinic acid and salts thereof. Or a combination with an oxyaldehyde, a water-soluble iron salt, or the like, or a peroxide such as a persulfate, a percarbonate, or a perborate, or 2,2′-azobis (2-amidinopropane) and a salt thereof; Water-soluble azo initiators such as 2,2'-azobis (N, N'-dimethyleneisobutylamidine) and its salts, and 4,4'-azobis (4-cyanovaleric acid) and its salts can be used. . In preparing the polymer emulsion used in the present invention, it is preferable to use the water-soluble azo initiator in a range of 0.1 to 3% by weight based on the amount of the unsaturated monomer constituting the polymer emulsion.

The polymer emulsion of the present invention can be prepared by the following general emulsion polymerization using the above-mentioned unsaturated monomer, emulsifier and polymerization initiator as appropriate. That is, a monomer dropping method in which an emulsifier is dissolved in an aqueous phase, a part of an unsaturated monomer mixture is emulsified and solubilized, a polymerization initiator is added, and then the remaining unsaturated monomer is dropped as it is. Alternatively, an emulsifier, a pre-emulsification method in which a part of water and an unsaturated monomer mixture are previously mixed and emulsified, and the emulsified product is added dropwise, can be prepared. From the viewpoint of reducing the amount of polymer adhered, it is preferable to use a pre-emulsification method.

The polymer emulsion of the present invention has good workability when the viscosity at a solid content of 40% by weight is 50 to 200 cP (Brookfield viscometer).
In addition, those having a low viscosity can contain a solid content of 50% by weight or more. The emulsion of the present invention can be used in the form of an emulsion obtained by emulsion polymerization as described above. It is also possible to apply by diluting with water (polymer emulsion: water = 1: 1 to 10). It is preferable that the amount of application is appropriately changed depending on the condition of the base, and about 50 to 100 g / m ² is suitable for a normal steel material. As a coating method, brush coating, roller coating, spraying, or the like can be used. If a single coating cannot provide a sufficient coating amount, coating may be performed a plurality of times.

After application to a reinforcing steel bar, a steel plate, a steel pipe, or the like, concrete, mortar, or the like may be poured immediately. Is preferred.
In addition, since it has a high performance as a normal primer (adhesion between concrete and mortar), it shows its best performance when it is mixed on a cement hardened surface such as a repair section and a metal material surface such as a reinforcing bar. I do.

[0036]

The present invention will now be described more specifically with reference to examples and comparative examples. In the following examples, “parts” and “%” mean “parts by weight” and “% by weight”, respectively.

[Preparation of polymer emulsion] (1) Polymer emulsion no. No. 1 in a glass reaction vessel equipped with a thermometer, a stirrer, a reflux condenser, a nitrogen introduction pipe, and a dropping funnel. 3.0 parts of an emulsifier shown as 1 and 140.0 parts of water were charged and dissolved,
The inside of the system is replaced with nitrogen gas. Table 1 shows No. 50.0 parts of 100.0 parts of the unsaturated monomer mixture shown as 1 and 143.0 parts of the aqueous emulsifier solution previously dissolved were emulsified and mixed,
5.0 parts of these are added to the reaction vessel and the temperature is raised to 65 ° C. After the temperature was raised, 0.3 part of 2,2'-azobis (2-amidinopropane) dihydrochloride was dissolved in 0.8 part of water, added to the reaction vessel, and immediately emulsified with the residual unsaturated monomer. Object 14
5.0 parts were continuously dropped into the reaction vessel over 60 minutes, and polymerization was carried out at 65 ° C. After the completion of dropping, 180 ° C at 65 ° C
After aging for a minute, the polymerization is completed. After cooling to room temperature, the solid content was adjusted to 40%. 1
And

[0038]

[Table 1]

[0039]

[Table 2]

(2) Polymer emulsion No. 2-N
o. 6 Using the emulsifier of Table 2 and the unsaturated monomer of Table 1, Prepared according to 1. (3) Polymer emulsion No. 7 EVA (ethylene-vinyl acetate) emulsion commercially available [trade name: NS Hyflex HF-1000]
(Nippon Kasei).

[Confirmation of Properties of Polymer Emulsion] The average particle size of the obtained polymer emulsion was measured with a light scattering photometer (ELS-800 manufactured by Otsuka Electronics Co., Ltd.). [Primer evaluation test] Japanese Society of Finishings Standard M-10
1 An adhesion strength test was performed in accordance with “Quality Standard of Water Absorption Control Material for Coating Cement Mortar”. However, the substrate is 5m
An m-thick steel plate (300 × 300 mm) was used. Further, a three-fold dilution (polymer emulsion: water = 1: 2) was applied using a polymer emulsion water as a primer to 100 g / m ² . The composition of the coating mortar was cement: river sand = 1: 1, and the ratio of water cement was 38%. A specimen cured for 14 days at a temperature of 20 ° C. and a humidity of 80% was used as a standard test specimen. .

The evaluation was carried out by calculating the adhesion strength and the fracture surface condition in accordance with the above-mentioned standard, and a notch for attaching a jig for measuring the adhesion strength was formed on the surface of the specimen by 40 ×.
When inserted in a size of 40 mm, the ratio of peeling due to poor adhesion was calculated and defined as the floating ratio. Table 1 shows the above evaluation results.
And Table 3. Emulsion No. 1 to No. The adhesion performance of the example using the primer containing No. 5 was good in both the adhesion strength, the fracture surface state, and the floating rate in both the standard and the water resistance evaluation.

[0043]

[Table 3]

[0044]

According to the primer composition of the present invention, the adhesiveness between a metal material such as a reinforcing steel bar or a steel plate and a hydraulic inorganic material such as concrete or mortar can be enhanced.
Further, the steel material coated with the primer of the present invention can be used as a rust preventive agent by spraying and applying it to the reinforcing steel laid when constructing a new concrete structure because the progress of rusting is extremely slow.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C09D 133/10 C09D 133/10 E04G 23/02 E04G 23/02 D // (C08F 230/02 (C08F 230/02 220 : 12) 220: 12) F-term (reference) 2E176 AA04 BB27 4J011 KA02 KA04 KA06 KA14 KA15 KB14 4J038 CG141 CH031 CJ161 CL001 GA06 GA14 HA156 MA08 MA10 NA03 NA12 PB05 4J100 AL03Q AL04Q AL08P BA03P BA65P CA23P

Claims (1)

[Claims] An emulsion copolymerization of an unsaturated monomer mixture containing an unsaturated monomer having a phosphate group and at least one unsaturated monomer selected from acrylates and methacrylates. A primer composition for civil engineering and construction, comprising a polymer emulsion obtained as an essential component.