JP7193064B2 - Concrete formwork remover - Google Patents

Description

The present invention relates to a concrete form release agent. In particular, it relates to a concrete formwork release agent that is excellent in mold releasability of the formwork of a concrete molded product, suppression of adhesion of cement scum to the formwork, and easiness of cleaning the formwork.

Conventionally, when manufacturing concrete products, concrete is poured into a mold made of steel, ceramic, synthetic resin, etc., compacted by vibration or the like, steamed, sprayed with water, cured with wet cloth, and then released from the mold. At this time, in order to prevent the concrete from adhering to the formwork, a release agent is generally applied to the formwork in advance to facilitate the release from the formwork.

Concrete mold release agents are based on mineral oil, animal or vegetable oil, and are broadly classified into oil-based types and water-based (emulsion) types.

In general, the oil-based type is used by adding additives such as wax, resin, fatty acid, metal soap, surfactant, and rust preventive to lubricating oil such as machine oil and turbine oil, and diluting it with undiluted solution or kerosene or light oil. .

On the other hand, the emulsion type is used by diluting and mixing the release agent with water to form an emulsion, which is applied or sprayed on the mold.

As for the mold peeling action mechanism, alkali ions in the concrete react with organic acids in the stripping agent to form a water-soluble fatty acid soap. Furthermore, the presence of calcium ions in concrete produces metal soaps such as sparingly soluble calcium soaps. This metal soap forms a release layer between the concrete and the formwork to exert a release effect, a physical release agent that adheres to the formwork and forms a barrier that prevents concrete from adhering, and a lubricating oil film on the surface. There is also a lubricating type release agent that creates a lubrication and releases the mold, and there is also a release agent that has a combination of these.

Fatty acids containing or blended with animal and vegetable oils as main components react with the alkali content of cement to form water-soluble fatty acid soaps. Then, the sparingly soluble calcium soap reacts with the calcium contained in the cement to exhibit a peeling effect.

In general, oil-based formwork release agents tend to leave oil stains and pinholes on concrete moldings, but on the other hand, they have excellent mold-releasing power, and there is little adhesion of cement scum (slag) to the formwork after demolding. is easy to clean.

Patent Document 1 discloses, as an oil-based mold release agent, a concrete release agent comprising a mineral oil-based solvent containing phospholipid and sorbitan ester or its ethylene oxide adduct. The form release agent described in Patent Document 1 is a release agent that exhibits excellent releasability, smoothness of the concrete surface, and rust prevention effect. However, since it uses a mineral solvent as a base oil, there are concerns about the effects of environmental pollution and worker exposure.

Patent Document 2 discloses, as an emulsion-type mold release agent, a release oil containing animal oil and/or vegetable oil and a nonionic surfactant of polyoxyethylene sorbitol fatty acid esters. . The mold release agent described in Patent Document 2 is a concrete release agent that has excellent mold releasability, emulsification stability, and reduces environmental pollution. However, no mention is made of the releasability of concrete, the adhesion of slag to the formwork, and the cleanability of the formwork in the case of continuous pouring into the same formwork.

Japanese Patent No. 2938629 Japanese Patent No. 4205585

Mineral oil contains organic volatile components (VOCs) and components that are harmful to the human body, so there are concerns about worker exposure, health hazards due to odors, environmental pollution due to leakage to the soil, and safety such as fires due to its high flammability. It is

Therefore, in recent years, concrete form stripping agents that are designed to reduce worker and environmental pollution have been on the market and are becoming widespread.

These stripping agents are based on animal and vegetable oils and fatty acid esters, do not contain harmful components such as VOCs, and are low in flammability. It is also attracting attention from the point of view of risk assessment related to
Surfactants, rust preventives, and the like may be added as additives, and are usually diluted and mixed with water or pre-diluted and used in the form of an emulsion.

Compared to the oil-based release agents that use mineral oil as the base oil, these are often superior in the appearance of concrete moldings (less oil stains, air bubbles, and pinholes), but slag adheres to the formwork after demolding. There is a drawback that the formwork is easily soiled by the generated metallic soap, requiring labor to clean. When repeatedly pouring concrete, the formwork must be cleaned in advance with a scraper, sander, or the like, and it is difficult to remove from the formwork, which greatly impairs workability.

The object of the present invention is to solve the above problems by improving the releasability from the formwork, the appearance of the concrete product after demolding, and the emulsion stability when diluted and mixed with water, as well as the conventional vegetable oil as the base oil. To provide a concrete form stripping agent which reduces the labor for cleaning the form due to the adhesion of slag to the form after demolding, which is a drawback of the emulsion type stripping agent, and improves the workability.

Therefore, the inventors of the present invention have conducted intensive studies in view of the above problems, and as a result, have found that the above problems can be improved by blending animal and vegetable oils with polyoxyethylene glyceryls, which are fatty acids having a specific alkyl chain.
That is, the present invention is a form stripping agent for concrete, characterized by containing an animal or vegetable oil and a nonionic surfactant of fatty acid polyoxyethylene glyceryls having a linear/branched alkyl group of C8 to C22 carbon atoms. be.

The present invention includes the following aspects.

Item 1, (A) an animal or vegetable oil and (B) a fatty acid polyoxyethylene glycerin ester having a linear/branched alkyl group of C8 to C22 carbon atoms is used as a formwork release agent for concrete.

Item 2, the concrete mold release agent according to item 1, wherein the HLB value or mixed HLB value of (B) is in the range of 7 to 13.

Item 3. The mold release agent for concrete according to Item 1 or 2, wherein the mold release agent contains 1 to 20% of (B).

Item 4. The concrete mold release agent according to any one of Items 1 to 3, which is used by diluting and mixing the concrete mold release agent with water.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided a concrete mold release agent that has good releasability and reduces adhesion of concrete scum to the mold after demolding, thereby saving the time and labor required for mold cleaning. According to the concrete mold release agent of the present invention, it is expected that concrete products can be produced efficiently.

Specifically, the concrete mold release agent related to the present invention for achieving the above object is as follows.

The mold release agent for concrete of the present invention contains (A) an animal or vegetable oil and (B) fatty acid polyoxyethylene glycerin esters having a linear/branched alkyl group of C8 to C22 carbon atoms.

(A) Animal and vegetable oils Animal and vegetable oils are fats and oils derived from animals and/or plants. The animal or vegetable oil preferably has a flash point of 250° C. or higher at 1 atm. Animal and vegetable oils to be used include, for example, vegetable oils such as rice oil, rapeseed oil, corn oil, soybean oil, sesame oil, olive oil, coconut oil, castor oil, palm oil, palm kernel oil, linseed oil, cottonseed oil, peanut oil, and tung oil. , beef tallow, lard, and animal oils such as fish oil, preferably rice oil, rapeseed oil, corn oil, soybean oil, sesame oil, olive oil, castor oil, palm oil, cottonseed oil, peanut oil, vegetable oils such as tung oil, and beef tallow. , lard, and animal oils such as fish oil.

The animal and vegetable oils of the present invention can be used singly or in combination of two or more.

Refined or crude animal and vegetable oils can be used. Animal and vegetable oils are preferably liquid at room temperature so as not to solidify during production or storage.

Animal and vegetable oils can be about 80 to 99% by mass of the total mass of the concrete mold release agent of the present invention.

(B) Fatty acid polyoxyethylene glycerol esters (fatty acid polyoxyethylene glyceryls, nonionic surfactants)
The fatty acid polyoxyethylene glycerol esters (fatty acid polyoxyethylene glyceryls) of the present invention contain 1 to 3 (preferably 3) polyethylene glycols (the total number of ethylene oxide added moles is about 3 to 60 on average) per hydroxyl group of glycerin. , preferably about 3 to 20) are ether-bonded, polyethylene glycol and / or 1 to 3 hydroxyl groups that are not ether-bonded to polyethylene glycol and carbon atoms C8 to C22 (preferably C10 to C20, more preferably C12 to It has a structure in which C18) is ester-bonded with a fatty acid having a linear/branched alkyl group. Fatty acid polyoxyethylene glycerin esters are known to act as nonionic surfactants.

The fatty acid having an alkyl group of C8-C22 carbon atoms may be either linear or branched. A fatty acid having a branched chain is particularly preferred. Isostearic acid is particularly preferred from the viewpoint of economy and availability.

Examples of fatty acid polyoxyethylene glycerin esters include caprylic acid/capric acid polyoxyethylene (average ethylene oxide (hereinafter abbreviated as EO) added mole number 4 to 8) glycerin esters, (mono, di, tri) Polyoxyethylene oleate (average number of EO addition moles 5 to 30) glycerin esters, (mono, di, tri)polyoxyethylene stearate (average number of EO addition moles 5 to 30) glycerin esters, (mono, di, Tri) polyoxyethylene isostearate (average number of moles of ethylene oxide added: 3 to 60), glycerin esters, and the like.

The HLB value (Hydrophilic-Lipophilic Balance) of the surfactant alone and when mixed is 7 to 13 from the viewpoint of emulsion stability, solubility in base oil, and defoaming of bubbles generated when concrete is placed. is more preferable.

The HLB value is a value that indicates the degree of affinity of a surfactant between water and oil, and can be determined by the Griffin method.

Also, the HLB value when a surfactant is mixed can be determined by weighted average of the HLB values of each surfactant component.

The (B) fatty acid polyoxyethylene glycerin ester type nonionic surfactant having a linear/branched alkyl group of C8 to C22 carbon atoms, which is blended in the present invention, may be used singly or in combination of two or more.

The blending ratio of the fatty acid polyoxyethylene glycerin esters is not limited as long as it is dissolved in the release agent and an emulsified state is obtained when diluted and mixed with water. The mixing ratio of the fatty acid polyoxyethylene glycerin ester in the concrete mold release agent of the present invention can be about 1 to 20% by mass, preferably 3 to 15% by mass, based on the total mass.

(C) Additives The concrete mold release agent of the present invention may further contain commonly used additives.

Optional components include rust inhibitors, antioxidants, antifoaming agents, preservatives, viscosity index improvers, pour point depressants, and the like. These are about 5% by mass or less in the total mass of the concrete mold release agent of the present invention.

The concrete form stripping agent of the present invention is diluted with water such as tap water, mixed well, and used in the form of an emulsion. When diluted with water, the dilution concentration is, for example, 1- to 30-fold, more preferably 5- to 10-fold.

The method of applying the concrete mold release agent of the present invention to the mold is not limited and can be either spraying or mopping. Also, if the spraying amount or application amount is too large, ^{discoloration} or color unevenness of the concrete product may occur, and if it is too small, the effect may not be sufficiently obtained.

The concrete mold release agent of the present invention is various cements such as portland cement, blast furnace cement, fly ash cement, silica cement, and ecocement. Admixtures (materials) can also be used in concrete mixed with AE water reducing agents, rust preventives, fly ash, silica fume, and the like.

EXAMPLES The present invention will now be described with reference to examples. However, the scope of the present invention is not limited to these examples.

The release agents used in the examples are the release agents of the present invention (Examples 1-3) and comparative release agents (Comparative Examples 1-4).

Examples 1-3
Animal and vegetable oils and fatty acid polyoxyethylene glyceryls (nonionic surfactants) were mixed according to the formulation shown in Table 1 below to produce a concrete mold release agent.

Comparative Examples 1-3
According to the formulation shown in Table 2 below, a concrete formwork release agent was produced as a comparative example.

Comparative example 4
As Comparative Example 4, a concrete form release agent which does not belong to the scope of the present invention and has a commercially available soybean oil as a base oil was used.

Except for Comparative Example 1, each raw material was heated to 60° C. and mixed and dissolved while stirring well to obtain a release agent composition.

Evaluation method The release agents of Examples 1 to 3 and Comparative Examples 2 to 4 were diluted and mixed with water in a steel mold of 10 cm in length, 10 cm in width and 60 cm in length, and 5 mL of the release agent in an emulsion state was applied. Concrete of the material and composition shown in 1 was placed. Comparative Example 1 was the same as Examples 1 to 3 and Comparative Examples 1 to 3, except that the undiluted solution was applied.

At the time of casting, compaction was performed with a table-type vibrator at 3000 vpm. After casting, steam curing was performed, and after 24 hours, the conditions of demolded concrete and formwork were observed. These placement tests were repeated four times for each release agent.

Samples for Evaluation Samples from Examples 1 to 3 and Comparative Examples 1 to 4 were used. In the evaluation, except for Comparative Example 1, each of Examples 1 to 3 and Comparative Examples 2 to 4 was diluted 5-fold with tap water, thoroughly mixed and stirred, and evaluated in the form of emulsion. In Comparative Example 1, the undiluted solution was used.
Evaluation of stripping agent specimens
The following evaluation items were evaluated according to the contents and evaluation criteria shown below.

(1) Emulsification stability test A release agent sample was diluted 5 times with tap water, homogenized with a homogenizer at 10,000 rpm for 1 minute, allowed to stand for 12 hours, and the emulsified state was visually observed.
◯: The emulsified state is maintained and no separation is observed.
△: Slightly separated.
×: Separation.

(2) Concrete releasability Detachment condition when lifted by a crane at the time of demolding.
◯: Easily demolded in 4 tests.
Δ: Slightly adhered to the form even once in 4 tests, and demolding was somewhat difficult.
x: Those that adhered to the mold even once in the four tests and were difficult to remove from the mold.

(3) Appearance After demolding, the appearance of the concrete product was visually evaluated.
◯: The surface of the specimen after demolding is smooth, and there are few cracks or pinholes (30 mmφ or more and less than 10 per side).
Δ: The surface of the specimen after demolding is smooth with few cracks and pinholes (10 or more and less than 50 pieces of 30 mmφ per side).
x: Many cracks and pinholes on the surface of the specimen after demolding (50 or more of 30 mm diameter per side).

(4) Adhesion of slag to the surface of the formwork after demolding and cleanability of the formwork ◎: Almost no slag adhering to the formwork after demolding in all four tests, requiring the formwork to be cleaned. Those that had no properties or were easily removed.
◯: At least once in 4 tests, a thin slag adhered to each surface of the mold after demolding, and was easily removed.
Δ: At least once in four tests, slag was thinly adhered to the entire surface of the mold after demolding, and labor was required to remove it.
x: After demolding, slag adhered to the entire surface of the mold every test, and labor was required to remove it.

The results are shown in Table 4 below.

It is clear that the concrete formwork release agent of the present invention has good emulsification stability and releasability, and little adhesion of concrete scum to the formwork after repeated placement and demolding. By using the concrete mold release agent of the present invention, it is expected that the time and labor required for mold cleaning can be omitted, and concrete products can be produced efficiently.

Claims (3)

(A) animal or vegetable oil and (B) a nonionic surfactant which is a fatty acid polyoxyethylene glycerin ester having a linear/branched alkyl group of C8 to C22 carbon atoms. hand,
(A) contains 80 to 99% by mass of animal and vegetable oil in the total mass of concrete form release agent,
(B) contains 1 to 20% by mass of a nonionic surfactant in the total mass of the mold release agent for concrete,
Form stripping agent for concrete to be diluted 1 to 30 times with water . 2. The concrete mold release agent according to claim 1, wherein the HLB value or mixed HLB value of (B) the nonionic surfactant is in the range of 7-13. 3. The concrete mold release agent according to claim 1 or 2 , which is used by diluting and mixing the concrete mold release agent with water.