JPS6032566B2 - Formwork forming method for cement products - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for molding cement products.

In general, the production of cement products such as cement mortar or concrete is carried out by pouring slurry into molds made of various materials and removing the mold after hardening. A mold release agent is applied to the inner surface of the formwork to prevent staining of the cement product surface or local setting failure. As the mold release agent, an aqueous emulsion such as paraffin, mineral oil, or metal soap, or a synthetic resin solvent such as vinyl chloride or phenol is used. When the mold release agent is applied to the mold surface, the mold release agent is not satisfactory and has problems such as staining the surface of the cement molded product and causing discoloration. The present inventors conducted intensive research in view of such problems and completed the present invention.The purpose of this invention is to have excellent demoldability, and to prevent corrosion of formwork without affecting the quality of cement products. The object of the present invention is to provide a mold forming method for manufacturing cement products without any process.

That is, the present invention uses higher fatty acid metal salts, higher fatty acid polyalcohol ester alkylene oxide adducts, and/or higher fatty acid polyalkylene glycol esters, alkylnaphthalenes, and/or sulfones of naphthalenes when molding a cement slurry. This is a method for forming a cement product in a formwork, characterized in that an aqueous dispersion containing an acid-formaldehyde high condensate is uniformly applied to the formwork at a rate of 10 to 50 times. The higher fatty acids of the higher fatty acid metal salts used in the present invention may have 12 to 22 carbon atoms and may be either saturated or unsaturated, or may be a mixture of both.

Further, the metal includes calcium, aluminum, zinc, zirconium, magnesium, beryllium, barium, copper, or lead. In particular, calcium, aluminum or bad lead salts of saturated fatty acids having 16 to 18 carbon atoms are preferred. The higher fatty acid metal salts may be used alone or in combination of two or more. Further, the higher fatty acid in the higher fatty acid polyhydric alcohol ester alkylene oxide adduct shown in the present invention is the same as in the case of the higher fatty acid metal salt described above, and the polyhydric alcohol that forms the ester with the higher fatty acid is glycerin, trimethylol. These include propane, solpitol, bentaerythritol, etc. Esters of higher fatty acids and polyhydric alcohols can be obtained by reacting the two according to conventionally known methods, and esters of 1 to 3 moles of higher fatty acids per 1 mole of polyhydric alcohol, that is, monoesters, gesters, triesters, etc. It is. The alkylene oxide added to the higher fatty acid polyhydric alcohol ester is an alkylene oxide having 2 or 3 carbon atoms, and the number of moles added is 2 to 30 moles.

The alkylene oxides may be added alone or in a mixed manner, and when added in a mixed manner, the form of addition may be block or random. The applicable range of the number of moles of alkylene oxide to be added differs depending on the type of higher fatty acid and the type of ester, but in general, the higher the molar ratio of higher fatty acid to higher fatty acid polyhydric alcohol with a larger number of carbon atoms, the higher the number of added moles. The number of moles is large, and the proportion of ethylene oxide in alkylene oxide is large.

If the number of moles of the alkylene oxide added is 4.0 mm above the range of 2 to 30 moles, the hydrophilicity will be insufficient, and if the number is also large, the higher fatty acid metal salt will not wet properly.

The higher fatty acid polyhydric alcohol ester alkylene oxide adduct exhibits a more favorable synergistic effect with other mixed components when ethylene oxide is used as the alkylene oxide.

Further, the higher fatty acid in the higher fatty acid polyalkylene glycol ester according to the present invention is the same as that of the higher fatty acid polyhydric alcohol ester alkylene oxide adduct described above.

The polyalkylene glycol that forms an ester with a higher fatty acid has 2 or 3 carbon atoms, and may be used alone or in combination, or may have different alkylenes in one molecule, and its shape may be block or random. But it's okay. The molecular weight of the polyalkylene glycol is 100 to 1200, and the ester is 1 to 2 moles of polyalkylene glycol to 1 to 2 moles of higher fatty acid.
It refers to the monoester or gester which is commonly referred to as mole.

The molecular weight of polyalkylene glycol varies depending on the type of higher fatty acid and the type of ester, but in general, the higher carbon number of the esterified higher fatty acid is higher, the molecular weight is higher, and a larger proportion of ethylene oxide is required. be.

If the molecular weight of the polyalkylene glycol is smaller than the above-mentioned range, hydrophilicity will be insufficient, and if it is larger, the overflow of higher fatty acid metal salts will be poor.

The higher fatty acid polyalkylene glycol ester exhibits a more favorable synergistic effect with other mixed components when the polyalkylene glycol is polyethylene glycol.

This also includes higher fatty acid alkylene oxide adducts, which are considered to be substantially the same as higher fatty acid polyalkylene glycol monoesters.

The number of moles of alkylene oxide added in this case corresponds to the molecular weight of polyalkylene glycol, and specifically is about 2 to 30 moles.

The alkylnaphthalene and/or naphthalene sulfonic acid formaldehyde high condensate shown in the present invention has 1 to 4 carbon atoms.
Alkylnaphthalene, naphthalene, or a dry distillate of lime containing substantially alkylnaphthalene or naphthalene as a main component, is sulfonated using a sulfonating agent such as concentrated sulfuric acid or fuming sulfuric acid in a conventional manner, and then formalin is used. The polymer is highly condensed and preferably has an average molecular weight of 1000 or more. Due to the additive effect of mixing the above components, a peeling effect between the cement product and the formwork can be obtained.

In particular, 30 to 95 parts by weight of higher fatty acid metal salt, 1 to 15 parts by weight of higher fatty acid polyhydric alcohol ester alkylene oxide adduct or/and higher fatty acid polyalkylene glycol ester, alkylnaphthalene and/or naphthalene sulfonic acid formaldehyde. 4 to 6 high condensates
A more favorable peeling effect can be obtained than when the amount is mixed in the range of 5 parts by weight, which is preferable.

Further, the present invention is usually prepared in the form of an aqueous dispersion, and is preferably used after being diluted with water if necessary.

When using the aqueous dispersion of the ingredient, brush it on the molded surface of metal foam, waterproof plywood, hardboard, wood, etc.
Alternatively, immediately after applying a predetermined amount by spraying with an air sprayer, or after drying the aqueous dispersion by air drying, hot air drying, etc., cement mortar or concrete is poured and used as a mold frame. .

The amount of the aqueous dispersion applied varies depending on the type of mold, surface condition, etc., and for example, it is necessary to use a larger amount for hardboard, wood, etc. than for metal foam.

Furthermore, compared to a new mold, it is necessary to apply a larger amount of hot water to a mold that has already been used several times. Considering the various conditions mentioned above, the amount of the aqueous dispersion to be applied must be at least 1 part of the active ingredient; if it is less than that, the desired mold release property will be degraded. Furthermore, it is advantageous in terms of surface finish and cost that the maximum amount of coating does not exceed 5 parts per coat based on the active ingredient. If it is used in excess of the above range, it may conversely contaminate the cement mortar or concrete surface, which is undesirable. More preferably, the amount of active ingredient applied is 2
It ranges from 0 to 10 females. The higher fatty acid polyhydric alcohol ester alkylene oxide adduct and/or higher fatty acid polyalkylene glycol ester used in the present invention is a ester-based nonionic surfactant that promotes wetting of higher fatty acid metal salts and acts as a dispersant. When left in contact with cement, which is a strong alkaline agent, the ester bonds are broken in a relatively short period of time, the surface activity decreases, and the hydrophilicity decreases.

In addition, alkylnaphthalene and/or naphthalene sulfonic acid formaldehyde high condensate can be used in combination with higher fatty acid polyhydric alcohol ester alkylene oxide adduct or/and higher fatty acid polyalkylene glycol ester to form water of higher fatty acid metal salt. It has the effect of significantly improving dispersibility and dispersion stability. Peeling of the cement product from the formwork due to the synergistic effect of the above ingredients applied to the formwork does not occur rapidly upon contact with the cement slurry, but occurs gradually while the cement hardens, and the surface of the cement product becomes delicate. This has the effect of smoothing the surface and preventing the formation of pinholes or small holes. In addition to the components used in the present invention, nonionic surfactants and anionic surfactants include polyoxyethylene alkyl phenyl ether and polyoxyethylene alkyl ether type nonionic surfactants for wetting higher fatty acid metal salts. There are also surfactants and anionic surfactants such as sodium alkylbenzenesulfonate and sodium lower alkylnaphthalenesulfonate, which are commonly known as dispersants, but these have synergistic effects even when mixed and used as substitutes for the components shown in the present invention. No action is shown, and effects such as those of the present invention cannot be expected.

According to the present invention, a cement product such as cement mortar or concrete, which has excellent mold releasability and has a smooth surface and excellent surface appearance and properties, can be obtained.

The present invention will be explained below with reference to Examples. In addition, the aqueous dispersion shown in the examples is a mixture of a specified amount of a higher fatty acid polyhydric alcohol ester alkylene oxide adduct or/and a higher fatty acid polyalkylene glycol ester (hereinafter referred to as component B) in a specified amount of water. A higher fatty acid metal salt (hereinafter referred to as component A) is added to the diluted product, and after homogenization, a specified amount of alkylnaphthalene and/or a sulfonic acid formaldehyde high condensate of naphthalene (hereinafter referred to as component C) is added. The mixture was dispersed uniformly to make the active ingredient 10%.

Example: Particle size 5 for normal Boltland cement? The following river sand was added twice by weight, water was added in an amount of 6% by weight based on the cement, and the mixture was mixed uniformly to form a slurry.

Next, a predetermined amount of a dispersion containing the three ABC components shown in Table 1 is applied to a form board made of steel, waterproof plywood, and FRP.
Air dried indoors. Each mold board (90 skins x 90 skins)
The cement slurry was poured on top to a thickness of 2 skins and allowed to harden. After 2 hours, the cured product was demolded and its releasability and surface finish were examined.

The results are shown in Table 2. Judgment was based on the table below.

Each symbol in Table 1 indicates each component below, and the numerical values are parts by weight of each component.

As is clear from Table 2, the method of the present invention had excellent peelability during demolding of the cement product, and the surface of the cement product was smooth and no staining was observed.

Claims (1)

[Claims] 1. When forming a cement slurry into a mold, it contains higher fatty acid metal salts, higher fatty acid polyhydric alcohol ester alkylene oxide adducts, and/or higher fatty acid polyalkylene glycol esters, alkylnaphthalenes, and/or sulfonic acid formaldehyde high condensates of naphthalenes. Place the aqueous dispersion in the mold in an amount of 10 to 10% by weight of the mixed components.
A mold forming method for cement products, characterized by uniform application of 500 g/m^2.