JPS58110456A - Rust inhibitor for steam-cured lightweight foamed concrete reinforcing bar - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention Steam-cured lightweight cellular concrete (hereinafter abbreviated as A, 1.0) is a slurry made by adding additives such as aluminum to a mixture of silicic raw materials, calcareous raw materials, and water. OA is manufactured by pouring the material into a formwork with reinforcing steel, allowing it to foam and semi-cure, then cutting it into the desired shape using piano wire, etc., and curing it with steam in an autoclave. , L, and O are lightweight construction materials with excellent heat insulation and durability, so they are used in various types of construction including high-rise buildings.

However, since A, L, and O have voids of approximately go%, they have the disadvantage that moisture and corrosive substances can penetrate inside and corrode the reinforcing steel.

To this end, reinforcing reinforcing bars are conventionally treated with appropriate anti-corrosion treatment. Until now, as a rust preventive agent for reinforcing reinforcing bars for A, L, and O, water-based slurry (Tokuko Showa 3A-2
3g'/9, da/-2g11.3.5/-3720
2, -3/-! ;g3'1 Publication) and products in which anti-rust pigments, etc. are added to a solution of natural or synthetic resin in an organic solvent (Tokukosho!;0-15g1 Publication and product names: Inato A/, LKOHIJR, OHIMI C, GM
BH Co., Ltd.) etc. were used.

However, while the anti-rust coating made of cement is hard and has sufficient bonding strength, the coating is breathable, so in order to have sufficient anti-corrosion properties, it is necessary to make the coating as thick as possible. . If the thickness of the coating is increased, the cement itself is brittle and will not follow the bending of the reinforcing bars, making it more likely to crack. Furthermore, since the diameter of the reinforcing bars including the coating becomes thick, cavities are likely to form above the reinforcing bars during the foaming process, and furthermore, the pot life is relatively short due to hydration of the cement. In addition, rust preventives that use organic solvents do not have the above problems, but organic solvents are harmful to the human body, and there is a risk of fire or explosion. It has the disadvantage of reduced adhesive strength.

In addition to these rust preventives, there are also examples of using synthetic rubber, thermoplastic resins, thermosetting resins, and inorganic powders in combination.
-400! ;7,! ;! -400jTg Publication), but even if this product is used for A, L, and C, the adhesive strength is insufficient, cranks occur during the work process, and rust prevention is insufficient, so it is not sufficient for all of them. It wasn't.

In view of the above-mentioned current situation, the present invention has a relatively thin coating that has sufficient rust prevention properties, does not cause cranking when the reinforcing bars are bent, is flexible, and has a strong bond between the reinforcing bars and A and L.

To provide a rust preventive agent for A, L, and O reinforcing bars that has strong adhesion to A, L, and O reinforcing bars, has a strong adhesion force to A, L, and O reinforcing bars, has little decrease in adhesive force even at high temperatures after autoclave curing, and is economically inexpensive. It is.

That is, the present invention adds inorganic powder consisting of Portland cement and silica powder of 100 mesh (Tyler sieve) or less to a polymer emulsion consisting of high styrene SBR latex, asphalt emulsion, and polystyrene emulsion added as necessary; This is a rust preventive agent for A, L, and O reinforcing bars, which is made by adding water and additives such as a dispersant, a water reducer, a setting retardant, an antifoaming agent, and an antisettling agent as necessary.

To explain the rust preventive agent according to the present invention in more detail, (1) a latex of styrene BBH with a styrene bond content of 65 to 3% by weight, and an asphalt emulsion, each having a solid content of 0.9 to 3% by weight; A polymer emulsion (waste, styrene bond amount!; 0-As weight% of SB
A polymer emulsion in which a small amount (less than half of the amount of SBH latex) of polystyrene emulsion is added to the latex of H to make the styrene bond amount 6S to 5% by weight, and an asphalt emulsion is mixed in the same ratio as (A). B).

An inorganic powder (0) made by mixing silica powder with a weight ratio of 7.3 to 1,5 parts by weight using a Tyler sieve to 100 meshes or less of silica powder to Portland cement.

3 parts of (0) per 1 part by weight of solid content of (A) or (B)
This is a rust preventive agent for A, L, and O whose main component is a mixture of ~6 parts by weight of Mighty (manufactured by Kao Soap), Balitsuku (manufactured by Fujisawa Pharmaceutical), etc. Set retardants include sodium hebutonate, sugar, etc. Antifoaming agents include the trade name Anti-Floss (Dai-Kogyo Pharmaceutical Cylinder), silicone (Shin-Etsu Chemical), etc. As an anti-settling agent, additives such as bentonite and asbestos and an appropriate amount of water may be added.

The SBH latex and asphalt emulsion used in the method of the present invention, and the polystyrene emulsion added as necessary, are added to have appropriate hardness, flexibility, and water impermeability, and to create a strong coating and adhesion to reinforcing steel. Yes, commercially available cement mixtures can be used, but 1. For SBH latex, the amount of styrene bonded is 6 to avoid cracking and to increase adhesive strength.
A high styrene SDR latex with a sMIk% of 5 to 7 sMIk% is suitable, and a SDR latex with a styrene binding amount of 50 to 65% by weight is suitable.
It can also be used by adding a small amount of polystyrene emulsion to BH latex to increase the amount of styrene bonded from 6S to 75% by weight, but if the amount of styrene bonded is 50% by weight.
In the following SBH latexes, for example those made by adding a large amount of polystyrene emulsion to the above-mentioned SBH latex with a bonding amount of 30% by weight to make the styrene bonding amount 6S to 5% by weight, the pot life of the rust inhibitor is short. This is undesirable because it causes cracks in the reinforcing steel coating.

Furthermore, if an SBR latex with a styrene bond content of less than t is used, the rubber elasticity becomes strong, and the coating becomes soft and the adhesive force decreases. To prevent this, adding a large amount of inorganic powder to the above materials improves hardness and adhesive strength, but 1. Rust resistance also decreases due to decreased flexibility and increased water absorption.

It is also possible to add a thermosetting resin, such as a phenolic resin or an epoxy resin, to the above latex to increase its hardness and adhesive strength, but this may shorten the pot life or produce a irritating odor. In this case, cracks are likely to occur in the coating.

In addition to SDR latex, it is also possible to use commercially available acrylic emulsions, polyurethane emulsions, polyester emulsions, acrylic ester emulsions, etc. for cement mixing, but from a cost standpoint, the present invention The combination of laws is optimal.

Next, the solid content of the asphalt emulsion is O
The reason why it is set at 0q to 30g parts by weight is that if the asphalt emulsion is less than 0.9 parts by weight, the adhesion of the coating to the reinforcing steel will be poor, resulting in a decrease in adhesive strength, and the rust prevention will be poor. Above 50%, the formed film is soft,
This is because the reinforcing steel mat becomes brittle and its adhesive strength decreases, and the cross portions of the reinforcing steel mat tend to crack.

This is because the addition of an inorganic powder consisting of cement and silica powder of less than 100 mesh is effective in compensating for the insufficient adhesive strength of the resin coating alone.

In addition to cement and powdered silica, powders such as talc, kaolin, calcium carbonate, lime, alumina, iron oxide, and zinc oxide can be used, but especially those that produce calcium silicate when cured in an autoclave. is valid,
Cement and powdered silica are preferred because they are inexpensive.

The cement is preferably ordinary Portland cement or moderate heat cement, and the powdered silica is pulverized silica or silica sand, as long as it does not quickly settle in the slurry, and the particle size is 100 mesh or less. There is no problem if there is. The mixing ratio of cement and powdered silica stone is /, 5:/ by weight.
-1,5 is preferable/, if the amount of cement is more than 3 to 1, the pot life will be shortened; conversely, if powdered silica stone is more than 9.5 to cement)/, 5, calcium silicate will be formed. The problem is that the adhesive strength decreases due to less IJ
In the present invention, 3 to 6 parts by weight of the inorganic powder @ is used for 1 part by weight of the solid content of the polymer emulsion (2). If it is less than 6 parts by weight, the coating will not only become soft and the adhesive force will decrease, but also the price will increase. Conversely, if it is more than 6 parts by weight, the flexibility of the coating will decrease and cracks will occur when the reinforcing bars bend. This is because it becomes more likely to occur, and the permeability of the coating increases, worsening the rust prevention properties of the reinforcing bars.

The rust preventive agent for A, L, and O reinforcing bars of the present invention may contain additives such as dispersants, setting retarders, etc., as described above, in order to improve workability and film properties. Added.

Further, water is added by adjusting the viscosity and concentration of the slurry 1, and increasing or decreasing it as appropriate so as to obtain the required coating thickness.

The rust preventive composition prepared as described above is stable and does not deteriorate in performance even if it is left in a sealed state for one month or more without evaporation of water after preparing the slurry. In addition, when continuously dipping reinforcing bars, even if the consumed and insufficient amount is replenished with new preparation, the properties of the rust preventive composition will not change or the performance will deteriorate. do not have.

The reinforcing bars A, L, and O manufactured using reinforcing bars treated with this rust preventive agent have sufficient adhesion and rust prevention properties, as seen in the examples.

The reason for this is not clear, but the autoclave curing in the A, L, and O manufacturing processes improves the anti-corrosion and dense layering properties of asphalt, the appropriate hardness, flexibility, and film-forming properties of SBR and polystyrene, and the effectiveness of cement and powdered silica. It is thought that the improvement in adhesion caused by the calcium silicate compound consisting of the following acts synergistically to form an excellent anti-rust coating.

Examples will be described below.

Example 1 Latex of high styrene SBH with a styrene bond amount of 70% by weight and a solid content of 45% by weight (trade name: Crossrene 5PX)
-/s Takeda Pharmaceutical) 60 parts by weight and an asphalt emulsion (trade name, Flint Coat-ya S) with a solid content of SS weight%
1 Shell Petrochemicals) 60 parts by weight, 50 parts by weight of ordinary Portland cement, powdered silica stone (Tokai Kogyo, patented) isθ parts by weight, and a dispersant under the trade name Mighty 130R (trade name).

Kao Soap) 1 part by weight, Sodium Hebutonate (Mie Kasei) 0. ! Add 0.2 parts by weight of Anti-Floss (trade name: Daiichi Kogyo Seiyaku) as an antifoaming agent and 70 parts by weight of water and mix well to obtain a viscosity of 3°O.
A rust preventive agent was made from a slurry of drinking water.

A reinforcing reinforcing bar with a diameter of 5.5 mff1 was immersed in the above rust preventive agent, and the gOC hot air drying, dipping, and drying operations were performed to give the reinforcing bar an average thickness of 0.3! mlN anti-rust coating was formed.

This reinforcing bar was fixed to a formwork, and A, L, and O with specific gravity O and S were manufactured according to the following conventional method.

Cut so that the reinforcing bar is located at the vertical center of the rectangular column of A, L, (!)
This was subjected to an adhesive force test using the punching method and
And a rust prevention test was conducted according to the Swedish standard (S engineering S1 g/l/l). To test pot life, use a container with a lid.
When adding the rust preventive agent of this example and leaving it in a sealed state,
When discarding 10% of this rust preventive agent every day and replenishing it with new rust preventive agent, we observed changes in the viscosity, gelation, and sedimentation of the rust preventive agent, and also observed changes in the viscosity of the rust preventive agent over a period of one month. A using the rust preventive agent.

L and O were made, and an adhesion test and a rust prevention test were conducted on the reinforcing bars. Further, after the reinforcing bars that had been subjected to anti-rust treatment were cured in an autoclave as they were, the reinforcing bars were bent at an angle of 50+1- and the occurrence of cracks was observed.

゛ As a result of the above tests, pot life (no change for more than 1 month), flexibility (no cracks), adhesive strength (20 to 9/Cm or more...the maximum load due to punching is removed by the surface area of the reinforcing bars) The results were satisfactory in terms of rust resistance (no rust), no cracks when bending the reinforcing bars, and so on.

Example 1 A product was produced in the same manner as in Example 1, except that the blending ratio of the raw materials was as shown in Table 1, and its properties were examined in the same manner.

The results are shown in Table 1 in comparison with a comparative example (using a rust preventive composition prepared with a blending ratio outside the claimed range).

Table note) Pot life: ○: There is no change for more than 1 month, or even if some sedimentation occurs, it returns to its original state with stirring.

Δ: gelatinized after 10~30 days Even if the sediment is stirred, it will not return to its original state. Dont return.

x: Gells within 10 days or does not return to its original state even if the sediment is stirred.

do not have. .

×; 3 No cracks occur after bending. Ru.

Adhesive strength (value where the maximum load due to punching is removed by the surface area of the reinforcing bar) ○; ko0kg7C1li or more △i 1O-j20119/e" ×ll0kg/scratch or less Rust prevention ○i DIN dakoko 3 and S work s 1g1
No rust in the anti-corrosion test conducted by TIT.

×: No rust observed in the rust prevention test. As is clear from the table, the rust preventive agent within the scope of the present invention showed sufficient results in all tests. The comparative example failed all tests except for the heat and heat.

Example 3 SBH with styrene content of 60% by weight and solid content of SO% by weight
Latex (trade name Crossren 0MX-02, Takeda Pharmaceutical Co., Ltd.) with a polystyrene emulsion with a solid content of 30% by weight (
The test was conducted in the same manner as in Example 1, except that 50% by weight of the product (trade name Crossrene SA-, 2de, Takeda Pharmaceutical) was added, and the mixing ratio of each raw material was as shown in Table 2. .

The results are shown in Table 2 in comparison with comparative examples.

As is clear from Table 2, compositions other than those of the present invention yielded unfavorable results such as shortened pot life, cracks, decreased adhesive strength, and decreased rust prevention. However, satisfactory results were obtained with all the compositions within the scope of the present invention.

Applicant: Sumitomo Metal Mining Co., Ltd. \DoP, ; , /

Claims (1)

[Claims] (1) Latex (a) of high styrene SBH with styrene bond amount O S ~ 75% by weight, styrene bond amount 30 ~
Add polystyrene emulsion to 65% by weight S, BR latex and add 4 styrene ills! r ~75% by weight (b), (a), or (b) with asphalt emulsion as solid content, respectively, 1 to 0.9 to 3. Polymer emulsion mixed in what weight ratio), cement and silica powder of less than 100 mesh /,! f vs./
- Inorganic powder (B) mixed at a weight ratio of 1.5, the above I
Steam curing in which water is added to a mixture of (A) and Φ), with A) and (B) as the main components, and B) in a weight ratio of 3 to B per solid content of A). Rust preventive agent for lightweight aerated concrete reinforcement.