JPH0569428A - Concrete release agent - Google Patents

Abstract

PURPOSE:To provide a concrete release agent utilized so as to be applied to a form in order to facilitate the demolding to the form used in concrete construction and the production of a concrete molded product. CONSTITUTION:A concrete release agent is composed of a mineral oil type solvent containing phospholipid and sorbitan fatty acid ester or an ethylene oxide adduct thereof. This release agent shows excellent effect in releasability and reduces the contamination of a form after demolding and finishes the surface of concrete smoothly and, therefore, the cleaning of the form or the repairing of a product is eliminated. Since the adsorbing force to the form is strong, anti-corrosion effect can be expected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a concrete applied to a formwork for facilitating demolding of the formwork used in various concrete works and production of concrete molded products. It relates to a release agent.

[0002]

2. Description of the Related Art Regarding the performance of a concrete mold release agent, it is easy to remove the concrete surface from the mold, but the appearance of the finished surface is not impaired and no rust is found on the mold. Things are also required. Conventionally, as a concrete mold release agent, mineral oil is used alone, or a mixed oil such as fatty acid and animal / vegetable oil based on mineral oil is used [for example, see Lubrication, 1982, (6) 17 ].

[0003]

However, the conventional mineral oils or the releasing agents based on mineral oils do not have sufficient releasability, and it is difficult to remove concrete from the form, A large amount of concrete adheres to the mold after molding, resulting in inferior smoothness of the concrete surface, resulting in poor surface aesthetics. Therefore, it is necessary to clean the concrete adhering to the formwork, repair the concrete surface, and the like, and there is a problem that work efficiency is reduced.

[0004]

In view of the above problems, the present inventor has conducted earnest studies to obtain a release agent having excellent releasability, and has completed the present invention. The present inventors have found that when a general oil-based mold release agent is used, the mold release agent is peeled off from the mold frame by physical impact or vibration of concrete placing on the mold frame or a vibrator, and the release agent remains on the mold frame. It has been found that the absence of the above causes a decrease in peelability. Therefore, the inventors of the present invention have completed the present invention by paying attention to the chemical adsorption force for increasing the adsorption force of the oil component to the metal mold. That is, the present invention relates to a concrete mold release agent comprising a mineral oil solvent containing a phospholipid and a sorbitan fatty acid ester or an ethylene oxide adduct thereof.

The phospholipid as used herein means phosphatidylcholine, phosphatidylethanolamine, etc.,
A typical example is lecithin obtained by extracting or purifying soybean or egg yolk. When this phospholipid and sorbitan fatty acid ester are mixed with mineral oil to form a mold release agent, the phospholipid is strongly adsorbed on the metal mold, and the presence of the phospholipid increases the adsorptive power of the mineral oil to the mold to improve releasability. It was found that it was significantly improved. It was also found that sorbitan fatty acid ester improves the solubility of phospholipids that are poorly soluble in mineral oil, and that a uniform and stable release agent can be obtained. The phospholipid used in the present invention refers to phosphatidylcholine, phosphatidylethanolamine, etc. as described above, and the representative one is natural lecithin obtained from soybean or egg yolk, and the extraction method and the purification method are particularly limited. Not a thing. The sorbitan fatty acid ester used in the present invention is a monoester, diester or triester of a saturated or unsaturated fatty acid having an alkyl group or an alkenyl group having 12 to 18 carbon atoms. From the viewpoint of solubility, the number of moles of ethylene oxide added is preferably 15 or less. Examples of sorbitan fatty acid esters or ethylene oxide adducts thereof include sorbitan monolaurate, sorbitan monooleate, sorbitan dioleate, polyoxyethylene sorbitan monooleate (ethylene oxide addition mole number 1 to 15 moles), and the like. It is possible to use one kind or two or more kinds.

The present inventor has also found that the content of phospholipid in the mineral solvent is 2 to 10% by weight, the sorbitan fatty acid ester or its ethylene oxide adduct is 0.2 to 5% by weight.
It was found that the range of (1) to (3) exhibits an extremely excellent peeling effect. Beyond these limits is economically disadvantageous,
On the other hand, if it is less than the lower limit, a sufficient effect cannot be obtained on peelability and product stability. The mineral oil used in the present invention is not particularly limited to spindle oil, machine oil, transformer oil, silicone oil and the like.

As a method for applying the release agent of the present invention to the mold, a mop coating method, a spray coating method, etc. are suitable.
The method is not limited to these, and any method is possible, and it can be used in a mold other than metal. Concrete using the release agent of the present invention, civil engineering,
It is not limited to architecture and secondary products, but applies to all concrete that uses formwork. The same applies to the type of concrete, and it can be widely used from zero-slump cemented concrete to high-fluidity concrete, for example, vibration-free concrete such as high-fluidity / non-separable concrete.

Therefore, the mixing conditions and materials of concrete are not limited, and various admixtures (agents),
For example, fly ash, slag, silica fume, high-performance water reducing agent, AE (air entrainment) agent, AE water reducing agent, foaming agent,
Concretes containing retarders, early strengtheners, water-soluble polymers, crack-reducing agents, sustained-release dispersants, etc. are targeted.

[0009]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Table 1 shows the contents of the release agent of the present invention and the comparative release agent used in the examples, and the properties of the dissolved state.

[0010]

[Table 1]

Table 2 shows the composition of the concrete used in the examples.

[0012]

[Table 2]

*; Mixing conditions of cement weight% concrete Cement (C); Normal Portland cement Specific gravity = 3.16 Water (W); Tap water sand (S); Kinokawa river sand Specific gravity = 2.58 Gravel (G); Takarazuka crushed stone Specific gravity = 2.60 s / a; Sand / (sand + gravel) admixture; Naphthalene-based high-performance water-reducing agent [Product name: Mighty 150, made by Kao Corporation] Concrete adjustment 100 l Kneading forced mixer [Pacific Metals Co., Ltd.] In [Production], all materials were added and mixed for 3 minutes. Fluidity of concrete The slump (cm value) was measured according to JIS A 1101 method, and it was 8.5 cm 2.

The peelability of the concrete (dirt on the mold) and the surface condition (aesthetic appearance) of the concrete were measured according to the following methods. Evaluation Test Method 2 to 4 ml of the mold release agent of the present invention or the comparative mold release agent shown in Table 1 is applied to an iron mold having a length of 10 cm, a width of 10 cm and a height of 30 cm by spraying. Next, concrete having the composition shown in Table 2 was placed in the form, and at the time of placing, the concrete was vibrated for 30 seconds with a table vibrator of 3000 vpm and filled. 2 days after casting
Observe the peelability (dirt of the form) and the condition of the surface of the demolded concrete. The state of adhesion of concrete on the surface of the demolding frame was observed with the naked eye, and judged by the following 5 grades. [Criteria] XX: Thickly adhered to the entire surface of the mold X: Partially thickly adhered △: Thinly adhered to the entire mold surface ○: Partially thinly adhered ◎: Almost no adhesion ・ Measurement of concrete surface condition Horizontal 10 cm, The number of surface voids in 200 cm ² having a height of 20 cm (including those having no smoothness and having a peeled surface) of 2 mm or more was measured.

Table 3 shows the results of the peelability (dirt of the mold) and the appearance of the surface of the demolded concrete.

[0016]

[Table 3]

*: Since the mixture is separated into two layers,
A uniform release film cannot be formed. From the results shown in Table 1, it was found that the products of the present invention had good compatibility and were homogeneous release agents.
From the results, it can be seen that the mold release agent of the present invention is an excellent mold release agent because it has releasability (fewer stains on the mold) and less voids on the concrete surface due to it, as compared with the comparative product.

[0018]

EFFECTS OF THE INVENTION The mold release agent of the present invention has excellent releasability, has little stain on the mold after demolding, and has a smooth concrete surface. Is eliminated. In addition, since it has a strong adsorption force to the form, it can be expected to have a rust preventive effect.

Claims (3)

[Claims] 1. A concrete mold release agent comprising a mineral oil solvent containing a phospholipid and a sorbitan fatty acid ester or an ethylene oxide adduct thereof. 2. The content of the phospholipid 2 in the mineral oil-based solvent is 2.
The mold release agent according to claim 1, wherein the content of the sorbitan fatty acid ester or its ethylene oxide adduct is 0.2 to 5% by weight. 3. The concrete mold release agent according to claim 1, wherein the phospholipid is lecithin.