JP4601967B2 - Primer composition, primer, and primer treatment method using the same - Google Patents

Description

  The present invention relates to a primer composition, a primer, and a primer treatment method using the primer composition, which are used for the purpose of improving adhesiveness when cement concrete is handed over by a cross-section repair method or the like.

One of the uses of polymer dispersions in the field of civil engineering and construction is a primer.
The primer has an effect of improving the adhesion strength between a mortar placed on the base such as concrete and the base such as concrete by applying to the base such as concrete.

In recent years, deterioration of concrete structures has progressed due to the effects of salt damage, neutralization, freezing and thawing, chemical corrosion, and the like, and the occurrence of cracks and floats on the surface is rapidly increasing.
As countermeasures, many repairs such as repairing parts such as repair mortar with excellent durability are carried out by checking the deteriorated part by hammering inspection, removing it with an electric pick, air pick, water jet, etc. Yes.

  At that time, a primer is used for the purpose of improving the adhesion strength between the newly-constructed repair mortar and the like and the groundwork such as concrete.

  It has been proposed to use a vinyl acetate-ethylene copolymer emulsion, a vinyl acetate polymer emulsion, an acrylate polymer emulsion, a copolymer emulsion thereof, or a mixed emulsion thereof as a primer. Although the effect which the adhesive force improves is obtained, it is not shown about containing an inorganic salt (refer patent document 1 and patent document 2).

In addition, even in the construction in a low temperature environment or in a season where strong wind blows at low humidity, the hardening of the mortar to be inherited on the adhesive surface is accelerated, so that the adhesive strength does not decrease. Polymer aqueous emulsions of ethylenically unsaturated compounds below ℃ and alkali metal chlorides, alkaline earth metal chlorides, zinc group element chlorides, iron group element chlorides, alkali metal silicates, It has been proposed to use, as a primer, a composition comprising a water-soluble inorganic salt selected from the group consisting of alkali metal rhodan salts and alkaline earth metal rhodan salts (see Patent Document 3).
However, if the water-soluble inorganic salt used is chloride, chloride ions may permeate and rust the reinforcing steel inside the concrete. There was a problem of lowering.

Furthermore, it has been proposed to use an epoxy-based primer that has higher adhesion than ethylene-vinyl acetate emulsion, styrene-butadiene emulsion, and acrylate emulsion, and has high durability such as alkali resistance. (See Patent Document 4).
However, this epoxy primer has a problem that it is highly irritating to the human body compared to other primers, and the primer treatment work by spraying becomes difficult.

Japanese Patent Publication No. 44-018757 Japanese Examined Patent Publication No. 62-059068 Japanese Patent Publication No. 50-038404 JP 2000-345101A

In this way, in the case of emulsion-based primers, there are problems such as falling easily due to their own weight if the mortar is thickly applied in the ceiling construction, and sufficient adhesion strength cannot be obtained. In some cases, it is easy to obtain sufficient adhesion strength, but in the construction of a large cross section, the work by spraying cannot be performed, and there is a problem that it is necessary to perform construction by brushing or roller coating, which takes time.
As a result of various studies to solve the above problems, the present inventors have obtained the knowledge that the above problems can be solved by using a specific primer composition, and have completed the present invention.

That is, the present invention comprises a polymer dispersion and one or more inorganic salts selected from the group consisting of potassium aluminate, lithium carbonate, and calcium nitrate, and aluminum sulfate. aluminum, the polymer dispersion 100 parts of solid basis, 2 to 100 parts, a primer composition to improve the adhesion strength between the repair mortar and cement concrete foundation, is La, thickener A primer composition containing the primer composition, a primer containing the primer composition, and a primer treatment method thereof.

Hereinafter, the present invention will be described in detail.
In addition, the cement concrete as used in this invention is a general term for paste, mortar, and concrete.
In the present invention, unless otherwise specified, parts and% are based on mass.

  The polymer dispersion used in the present invention (hereinafter referred to as the present polymer) is not particularly limited, but is a cement admixture polymer dispersion defined in JIS A 6203, such as acrylonitrile-butadiene rubber, styrene-butadiene. Rubber latex such as rubber, chloroprene rubber, and natural rubber, ethylene-vinyl acetate copolymer, polyacrylate ester, vinyl acetate vinyl versatate copolymer, styrene-acrylate ester copolymer, and acrylonitrile-acrylic Examples thereof include resin emulsions such as acrylic ester copolymers typified by acid esters.

In the present invention, the present polymer and one or more inorganic salts selected from the group consisting of aluminate, carbonate and nitrate, or the present polymer and aluminum sulfate are used in combination.
In the present invention, inorganic salts and aluminum sulfate all promote the coagulation of cement, and can be mixed with the present polymer or separately on a base such as cement concrete.

  The aluminate is not particularly limited, and specific examples include lithium aluminate, sodium aluminate, potassium aluminate, and calcium aluminate.

  Although it does not specifically limit as carbonate, Specifically, lithium carbonate, sodium carbonate, potassium carbonate, lithium hydrogencarbonate, sodium hydrogencarbonate, potassium hydrogencarbonate, etc. are mentioned.

  Examples of the nitrate include lithium nitrate, sodium nitrate, potassium nitrate, calcium nitrate, magnesium nitrate, lithium nitrite, sodium nitrite, potassium nitrite, calcium nitrite, magnesium nitrite, and barium nitrite.

Of these inorganic salts, it is preferable to use lithium salts or calcium salts that are considered harmless to the alkali-aggregate reaction.
The usage-amount of inorganic salt is 2-100 parts with respect to 100 parts of this polymer of solid content conversion, and 5-50 parts is preferable. If the amount is less than 2 parts, the effect of promoting the setting of cement is small, and the effect of improving the adhesive strength may not be expected.
In the present invention, inorganic salts can be used in the form of a powder or as an aqueous solution and mixed with the present polymer. Alternatively, the inorganic salts can be used separately from the present polymer and mixed on the ground surface of concrete or the like. is there.

In the present invention, it is possible to use aluminum sulfate in place of inorganic salts in order to promote cement setting.
The usage-amount of aluminum sulfate is 2-100 parts with respect to 100 parts of this polymer of solid content conversion, and 5-50 parts is preferable. If the amount is less than 2 parts, the effect of promoting the setting of cement is small, and the effect of improving the adhesive strength may not be expected.

In the present invention, it is preferable to further use a thickener for the purpose of increasing the viscosity of the primer composition, preventing dripping when used, or increasing the adhesive force on the adhesive surface of mortar or concrete. .
The thickening agent is not particularly limited, but celluloses such as methylcellulose, methylethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxyethylcellulose, and carboxymethylcellulose or salts thereof, polyacrylamide and its modified products, polyacrylamide moiety Examples include hydrolysates, sodium polyacrylate, sodium alginate, polyvinyl alcohol, and guar gum and xanthan gum.
The amount of thickener used is preferably 0.02 to 2 parts, more preferably 0.05 to 1 part, based on 100 parts of the present polymer in terms of solid content. If it is less than 0.02 part, dripping prevention and improvement in adhesive strength of mortar and concrete may not be expected. If it exceeds 2 parts, improvement in adhesive strength of mortar and concrete may reach its peak.
The thickener is preferably mixed in advance with the polymer, but when preparing an aqueous solution of inorganic salts or aluminum sulfate (hereinafter referred to as inorganic salts), it can also be mixed with the aqueous solution. Yes, it can be mixed with an aqueous solution of inorganic salts and the present polymer.

The primer composition of the present invention is preferably used by diluting 100 to 600 parts of water with respect to 100 parts of the present polymer in terms of solid content. If the solid content concentration of the polymer is too high, it may be difficult to obtain the effect of penetrating into the base.
Moreover, when using inorganic salts etc. as aqueous solution, when mixing with this polymer, it is preferable to adjust so that water may be 100-600 parts with respect to 100 parts of this polymer of solid content conversion.

The use amount of the primer composition of the present invention is preferably 50 to 1,000 g, more preferably 100 to 600 g, per 1 m ^{2 of} the surface to be coated or sprayed. If it is less than 50 g, the effect of improving the adhesive strength may not be obtained, and if it exceeds 1,000 g, the effect of improving the adhesive strength may reach its peak.

The primer treatment method of the primer composition of the present invention is not particularly limited, but any of a method of applying to a surface using a brush or a roller, or a method of spraying using a spray or a pressure sprayer is possible. It is.
In addition, polymer dispersions previously mixed with inorganic salts may be used, and inorganic salts can be used as aqueous solutions, and polymer dispersions and aqueous solutions such as inorganic salts can be applied or sprayed separately. It is.

  By using the primer composition of the present invention, it becomes possible to obtain adhesion strength at an early stage, and even in the construction of the ceiling surface, it is possible to obtain sufficient adhesion strength without peeling even if the repair mortar is thickened. It becomes.

  Hereinafter, the present invention will be described in detail based on examples.

To 100 parts of this polymer in terms of solid content, inorganic salts shown in Table 1 were mixed to obtain a primer composition, and further mixed with 200 parts of water to prepare a primer.
The surface of the mortar cured body polished with sandpaper was used as a base, the prepared primer 300 g / m ² was applied to the surface, the repair mortar was applied with a trowel, and the adhesion strength was measured after 2 days. The results are also shown in Table 1.

<Materials used>
Inorganic salts, etc. a: aluminate, potassium aluminate, reagent primary inorganic salts, etc. b: carbonate, lithium carbonate, reagent primary inorganic salts, etc. c: nitrate, calcium nitrate, reagent primary, main polymer A: ethylene-acetic acid Vinyl emulsion, solid concentration 45%
This polymer B: acrylate-acrylonitrile emulsion, solid content concentration 45%
Repair mortar: Polymer cement mortar for iron coating, commercial product

<Measurement method>
Adhesion strength: Measured with a Kenken-type pull-out tester in accordance with JIS A 1171

  The same procedure as in Example 1 was performed except that 100 parts of this polymer in terms of solid content was used as a primer composition using d such as inorganic salts shown in Table 2. The results are also shown in Table 2.

<Materials used>
Inorganic salts d: Aluminum sulfate, reagent grade 1

  The same procedure as in Example 1 was performed except that c20 parts of inorganic salts and the thickener shown in Table 3 were used as a primer composition with respect to 100 parts of this polymer A in terms of solid content. The results are also shown in Table 3.

<Materials used>
Thickener: methylcellulose, commercial product

  Example 1 except that c20 parts of inorganic salts and the thickener shown in Table 4 were used for 100 parts of this polymer A in terms of solid content, and the primer composition was applied as a primer composition in the amount shown in Table 4. As well as. The results are also shown in Table 4.

To 100 parts of this polymer A, inorganic salts shown in Table 5 and a thickener were mixed to obtain a primer composition, and 200 parts of water was further mixed to prepare a primer.
A 30cm long x 30cm wide x 6cm thick sandblasted concrete board is attached to the ceiling surface, and the prepared primer is sprayed on the surface to 300g / m ² and repaired once to a thickness of 7cm. Mortar was applied. The stability of the repaired mortar applied at that time and the adhesion strength after 7 days were measured. The results are also shown in Table 5.

<Measurement method>
Stability: If 7 cm cannot be applied, or even if it is applied, it will be peeled off after 1 day. If the mortar is not peeled off even after 1 day, it will be marked as ◯.
Adhesion strength: Two days after application, a core drill with an inner diameter of 55 mm drilled from the ground concrete plate to a depth of about 5 mm was used as a test specimen for the adhesion strength test for 5 days at 60% temperature and humidity. Measured using a Kenken pull-out tester.

Claims (4)

It contains a polymer dispersion and one or more inorganic salts or aluminum sulfate selected from the group consisting of potassium aluminate, lithium carbonate, and calcium nitrate, and the inorganic salts and aluminum sulfate are converted to solid content. A primer composition for improving the adhesion strength between cement concrete and repair mortar, characterized in that the amount is 2 to 100 parts per 100 parts of the polymer dispersion. Further, the primer composition according to claim 1, characterized in that it contains a thickener. Primer comprising the primer composition according to claim 1 or 2. A primer treatment method using the primer according to claim 3 .