JP2001322110A - Setting retarder for inorganic molding surface and method for manufacturing inorganic molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a setting retarder for an inorganic molding surface such as a concrete or the like capable of washing out in an arbitrary period such as, for example, by an operator who is free from an operation even after an accelerated curing and forming a uniform washing-out surface not having an unevenness. SOLUTION: The setting retarder for the inorganic molding surface comprises a water soluble polymer or an aqueous emulsion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of curing a cement composition such as cement, mortar or concrete, which delays the curing of the cement composition adhered to a mold surface combined with the cement composition. The present invention relates to a setting retarder used in the above, or a setting retarder which can be applied directly to a laying surface of a cement composition to facilitate washing out of an aggregate or formation of a pattern, and a method for producing an inorganic molded article using the same.

[0002]

2. Description of the Related Art Conventionally, a general method for forming a pattern on a concrete product surface is disclosed in Japanese Patent Application Laid-Open No. 48-7141.
2, JP-A-52-98725, JP-A-54-11952
2, JP-A-61-22904, JP-A-63-21670
And (3) a method of adhering a patterned rubber mat to a predetermined portion of the inner surface of a concrete casting formwork, (2) a method of engraving a surface of a concrete product by using only the method, etc. A) a method of forming a pattern on the surface of the concrete product using a tool such as a saw blade or a gold comb while the concrete is uncured. However, the method (1) requires the use of an expensive rubber mat each time, resulting in an increase in cost. The method (2) requires a skilled expert to perform engraving, and generates dust and the like during engraving. The method (3) has a drawback such that it cannot be performed on a product that is released from a mold. In order to solve such problems, Japanese Patent Application Laid-Open Nos. 53-9809, 5-50413, 4-163104, 7-279413, 11-262908 and 11-262908 have been disclosed. In the method, as in the above, it takes time and effort to increase the cost, and even in the case of using a retarder, it has not been able to completely overcome the drawbacks such as poor washability, and an improvement has been desired.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, to have excellent handleability, and to effectively delay the hardening of the surface of an inorganic molded article such as a cement composition. An object of the present invention is to provide a setting retarder and a method for producing an inorganic molded article using the same.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop a setting retarder having the above-mentioned preferable properties, and as a result, found that a setting retarder for the surface of an inorganic molded article comprising a water-soluble polymer or an aqueous emulsion was obtained. It has been found that the retarder satisfies the above object. Also, the present inventors,
It has been found that a method for producing an inorganic molded article in which the retarder is applied to a mold surface or a laying surface of an inorganic molded article such as a cement composition satisfies the above object.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The water-soluble polymer used in the present invention is not particularly limited.
Examples include hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, sodium polyacrylate, and water-soluble starch.

[0006] Among these water-soluble polymers, when polyvinyl alcohol is used, a setting retarder having a particularly preferable setting retarding effect can be obtained. The method for producing polyvinyl alcohol is not particularly limited, and can be obtained by saponifying a vinyl ester polymer by a known method.

[0007] Here, as the vinyl ester,
Examples thereof include vinyl formate, vinyl acetate, vinyl propionate, and vinyl pivalate. In general, vinyl acetate is preferably used.

The polyvinyl alcohol may be obtained by copolymerizing a copolymerizable ethylenically unsaturated monomer as long as the effects of the present invention are not impaired. Such ethylenically unsaturated monomers include, for example, acrylonitrile,
Methacrylonitrile, acrylamide, methacrylamide, trimethyl- (3-acrylamido-3-dimethylpropyl) -ammonium chloride, acrylamide-
2-methylpropanesulfonic acid and its sodium salt, ethyl vinyl ether, butyl vinyl ether, N
-Vinylpyrrolidone, vinyl chloride, vinyl bromide, vinyl fluoride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, sodium vinyl sulfonate, sodium allyl sulfonate, N-vinyl pyrrolidone, N-
N such as vinylformamide and N-vinylacetamide
-Vinyl amides. Also, thiolacetic acid,
In the presence of a thiol compound such as mercaptopropionic acid, a vinyl ester monomer such as vinyl acetate is polymerized, or a vinyl ester monomer and the above ethylenically unsaturated monomer are copolymerized. Can also be used.

The degree of saponification of the polyvinyl alcohol polymer used in the present invention is not particularly limited, but is usually at least 50 mol%, preferably at least 60 mol%, more preferably 7 mol%.
Those having 0 mol% or more are used. When the saponification degree is less than 50 mol%, there is a concern that the water solubility, which is an intrinsic property of polyvinyl alcohol, is reduced. The degree of polymerization of the polyvinyl alcohol is not particularly limited, but is usually 100 to 8
000 is used, and 300-3000 is more preferably used. Further, polyvinyl alcohol is preferably used as an aqueous solution.
It is used after adjusting to a concentration of 0%, preferably 0.3 to 30%. If the concentration is less than 0.1%, sagging may occur when applied by spraying or the like. Also, 40%
If the concentration exceeds the above range, the viscosity of the aqueous solution becomes too high, and there is a concern that the workability becomes poor.

The aqueous emulsion used in the present invention is not particularly limited. Anionic, cationic, amphoteric, nonionic low molecular surfactants conventionally known as dispersants, or various kinds of polyvinyl alcohol, hydroxy, and the like as protective colloids. Emulsification obtained by emulsion polymerization of radically polymerizable ethylenically unsaturated monomers, diene monomers or polyfunctional monomers in an aqueous solution containing one or more water-soluble polymers such as ethyl cellulose. Aqueous emulsions obtained by the post-emulsification method of polymers represented by polymerization type aqueous emulsions and polyurethane emulsions are used alone or in combination of two or more. Among them, an aqueous emulsion obtained by emulsion polymerization using polyvinyl alcohol as a protective colloid is particularly preferred because of its excellent setting retarding effect. As the aqueous emulsion, a polyvinyl acetate aqueous emulsion, an ethylene-vinyl acetate copolymer aqueous emulsion, an acrylate resin aqueous emulsion and the like are preferably used.

The ethylenically unsaturated monomers constituting the emulsion polymerization type aqueous emulsion dispersoid of the present invention include olefins such as ethylene, propylene and isobutene, vinyl chloride, vinylidene chloride, vinyl fluoride and vinylidene fluoride. Halogenated olefins, vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl versatate, vinyl pivalate, acrylic acid, methyl acrylate, ethyl acrylate, n-propyl acrylate, i-acrylate Acrylates such as propyl, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate, hydroxypropyltrimethylammonium acrylate, and methacrylic acid , Methyl methacrylate, ethyl methacrylate, n- propyl methacrylate i- propyl, n- butyl methacrylate, i- butyl methacrylate, t- butyl methacrylate, 2
Methacrylic acid esters such as ethylhexyl, dodecyl methacrylate, octadecyl methacrylate, hydroxypropyltrimethylammonium methacrylate, acrylamide, methacrylamide, N-methylolacrylamide, N, N-dimethylacrylamide, acrylamide-2-methylpropanesulfonic acid And its sodium salt acrylamide, trimethyl-
(3-acrylamido-3-dimethylpropyl) -ammonium chloride, 3-acrylamidopropyltrimethylammonium chloride, 3-methacrylamidopropyltrimethylammonium chloride, N-methylacrylamide, N-ethylacrylamide, diacetoneacrylamide, acrylonitrile, methacrylonitrile Allyl compounds such as nitriles, allyl acetate, allyl chloride, styrene monomers such as styrene, α-methylstyrene, P-methylstyrenesulfonic acid and its sodium and potassium salts, and other N-vinylpyrrolidone And diene monomers include butadiene, isoprene, chloroprene and the like. Further, polyfunctional monomers include divinylbenzene, tetraallyloxyethane, N, N'-methylenebis-acrylamide, 2,2'-bis (4-acryloxypolyethoxyphenyl) propane, 1,3-butylene Glycol diacrylate, 1,5-pentanediol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, polypropylene Glycol diacrylate, pentaerythritol triacrylate,
Trimethylolpropane triacrylate, pentaerythritol tetraacrylate, allyl methacrylate, 1,4-butanediol diacrylate, ethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, neopentyl glycol dimethacrylate, 1,6-hexanediol diacrylate Methacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, dipropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, trimethylolethane trimethacrylate, trimethylolpropane trimethacrylate, 2,2-bis (4-methacryloxy Polyethoxyphenyl) propane, N, N'-m
-Phenylene bismaleimide, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate,
Triallyl trimellitate, diallyl chlorendate,
And ethylene glycol diglycidyl ether acrylate. One or more of these monomers are used.

In carrying out the emulsion polymerization for obtaining the aqueous emulsion used in the present invention, the above-mentioned monomer is temporarily or continuously added in the presence of water, the above-mentioned dispersant and / or protective colloid, and a polymerization initiator. The usual emulsion polymerization method such as heating and stirring can be carried out,
In addition, a method in which a monomer is previously mixed and emulsified with a dispersant and / or an aqueous protective colloid solution and then emulsified may be continuously added.

The amount of the dispersant and / or protective colloid of the aqueous emulsion used in the present invention is not particularly limited, but is usually 0.2 to 100 parts by weight of the monomer.
It is 50 parts by weight, preferably 0.5 to 20 parts by weight.
If the amount is less than 0.2 parts by weight, the polymerization stability decreases,
If it exceeds 50 parts, the viscosity may be too high. The concentration of the aqueous emulsion is not particularly limited, but is usually adjusted to a concentration of 1 to 65%, preferably 2 to 60%. When the concentration is less than 1%, there is a possibility that sagging may occur when the composition is applied to a laying surface or a mold surface by spraying or the like. When the concentration exceeds 65%,
There is a concern that the viscosity of the aqueous emulsion becomes too high, resulting in poor workability.

The polymerization initiator is not particularly restricted but includes, for example, potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, 2,2'-azobis (2-amidinopropane) dihydrochloride, Redox system using cumene hydroperoxide, benzoyl peroxide, isopropylbenzene peroxide or the like alone or in combination with a reducing agent such as sodium bisulfite, tartaric acid, L-ascorbic acid, formaldehyde sodium sulfoxylate, and ferrous sulfate is used. Can be

The water-soluble polymer used in the present invention may be added later to the aqueous emulsion. There is no particular limitation on the mixing ratio in this case.

In addition to the water-soluble polymers and aqueous emulsions described above, other retarders such as polyacrylamide, polyhydroxysilane, ascorbic acid, etc. Isoascorbic acid may be used in combination. Also, fine powder slag,
Inorganic powders such as fly ash, calcium carbonate, silica fume (ultrafine silica powder) and the like may be used as a thickener or a filler.

Typical examples of the method of using the setting retarder as a setting retarder on the surface of the inorganic molded article include a method of attaching the setting retarder to a laying surface or a mold surface during the production of the inorganic molded article. There is no particular limitation on the method of adhesion, and a method of applying using a brush, a roller, a rubber spatula, or the like, or a method of spraying with a spray or the like can be adopted. By adjusting the amount of the setting retarder, the washing depth of the obtained inorganic molded product can be appropriately adjusted. In a normal case, the amount (solid content) of the setting retarder is preferably about 3 to 300 g / m ² . In the present invention, as a method of producing an inorganic molded article, a cement setting retarder is attached to a mold surface or the like, and then, a cement, a mortar, or a water-curable inorganic molding material typified by a cement-based composition such as concrete. First, there is a method. After the water-curable inorganic molding material has been injected, necessary curing is performed. There is no particular limitation on the curing method, and accelerated curing such as steam curing and autoclave curing can be performed, but it goes without saying that air curing may be used. After curing, since the setting retarder is adhered to the mold surface, the inorganic molded body can be easily removed from the mold, and can be washed out at an appropriate time using high-pressure water or a brush according to a conventional method. This washing does not need to be performed immediately after demolding, and even if accelerated curing is performed, after demolding,
This can be done after several days. The washing depth can also be adjusted by the washing conditions, that is, the pressure of the high-pressure water and the washing timing. In the present invention, the compounding composition of the cement-based composition such as cement, mortar or concrete to be poured into the formwork is not particularly limited, and may be the compounding component of the cement-based composition generally used conventionally. In addition, as a method for producing an inorganic molded article in the present invention, a method of attaching a setting retarder to a laying surface at the time of producing an inorganic molded article can also be mentioned, and even this method can perform uniform washing.

In the present invention, since a water-soluble polymer or an aqueous emulsion is used as a setting retarder, due to its excellent setting retarding effect, even after accelerated curing, for example, a worker's hand can be used at any time. Sometimes it is possible to wash out. In addition, by adjusting the concentration of the water-soluble polymer or the aqueous emulsion, it is possible to apply by various sprays or the like, and it is possible to uniformly adhere to a mold surface or the like. Due to such features, it is widely used as a method of applying to a formwork surface at the time of casting concrete, or as a surface decorative molding method at the time of producing a hardened cementitious product.

[0019]

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. In the following Examples and Comparative Examples, “parts” and “%” mean on a weight basis unless otherwise specified.

Example 1 As a water-soluble polymer of a setting retarder, polyvinyl alcohol (PVA-1; polymerization degree 1700, saponification degree 98.5 mol%);
Using a 10% aqueous solution of PVA-117 manufactured by Kuraray Co., Ltd., 10 g / m ² (solid content) was applied to the concrete form surface by spraying, and dried sufficiently at 20 ° C. The coating workability at this time was determined according to the following criteria. ○ Very good, △ slightly uneven, × sagging occurred, then using the above formwork,
A cosmetic mortar having the following composition was injected. Cement: 1, fine aggregate: 1.5, seed stone: 2.5 Then, after steam curing was performed for 24 hours, the mold was removed and washed out by a standard method. The finished surface of the obtained product was observed and judged according to the following criteria. ○ Almost uniform, Δ slightly uneven, × hardened and unwashable The results are shown in Table 1.

Example 2 Instead of using PVA-1 used in Example 1, a 10% aqueous solution of polyvinyl alcohol (PVA-2; polymerization degree 1700, saponification degree 88 mol%; PVA-217 manufactured by Kuraray Co., Ltd.) was used. The test was performed in the same manner as in Example 1 except that the test was used. Table 1 shows the results.
Shown in

Example 3 Instead of using PVA-1 used in Example 1, a 5% aqueous solution of polyvinyl alcohol (PVA-3; polymerization degree 2400, saponification degree 88 mol%; PVA-224 manufactured by Kuraray Co., Ltd.) was used. A test was conducted in the same manner as in Example 1 except for using the same. The results are shown in Table 1.

Example 4 Instead of using PVA-1 used in Example 1, hydroxyethylcellulose (HEC SP600; Daicel Chemical Industries, Ltd.)
The test was carried out in the same manner as in Example 1 except that a 2% aqueous solution of the same was used. The results are shown in Table 1.

Example 5 A test was conducted in the same manner as in Example 1 except that a 2% aqueous solution of sodium carboxymethylcellulose (CMC 1180; manufactured by Daicel Chemical Industries, Ltd.) was used instead of using PVA-1 used in Example 1. Was done. The results are shown in Table 1.

Example 6 The same as Example 1 except that a 3% aqueous solution of methylcellulose (MC) (60SH-4000; manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of using PVA-1 used in Example 1. Was tested. The results are shown in Table 1.

Example 7 Instead of using PVA-1 used in Example 1, an ethylene-vinyl acetate copolymer emulsion (OM-420 manufactured by Kuraray Co., Ltd.)
The test was performed in the same manner as in Example 1 except that 0%, a concentration of 55%, and polyvinyl alcohol as protective colloid (containing polyvinyl alcohol) were diluted to a concentration of 10%. The results are shown in Table 1.

Example 8 A glass container equipped with a reflux condenser, a dropping funnel, a thermometer, a nitrogen inlet, and a stirrer was charged with polyvinyl alcohol (PVA-
4, polymerization degree 500, saponification degree 88 mol%, containing mercapto group; 60 g of Kuraray Co., Ltd. M-205), ion-exchanged water 5
40 g was charged and completely dissolved at 95 ° C. Next, after adjusting the pH to 4 with dilute sulfuric acid, 60 parts of methyl methacrylate, 60 parts of n-butyl acrylate, and 0.6 part of n-dodecyl mercaptan were added while stirring at 150 rpm, and the temperature was raised to 70 ° C. after replacement with nitrogen. . The polymerization was started by adding 30 parts of 1% potassium persulfate, and a mixture of 240 parts of methyl methacrylate, 240 parts of n-butyl acrylate, and 2.4 parts of n-dodecyl mercaptan was continuously added over 2 hours. . Three hours after the start of the polymerization, the conversion reached 99.4%, and the polymerization was terminated. Solids concentration 51.7
% Of a stable methyl acrylate / n-butyl acrylate copolymer emulsion was obtained. PVA used in Example 1
Instead of using 1, methyl acrylate / n-
The test was conducted in the same manner as in Example 1 except that the butyl acrylate copolymer emulsion was used after being diluted to 10%. The results are shown in Table 1.

Comparative Example 1 Instead of using PVA-1 used in Example 1, 5 of citric acid was used.
A test was conducted in the same manner as in Example 1 except that a% aqueous solution was used.
The results are shown in Table 1.

Comparative Example 2 A test was conducted in the same manner as in Example 1 except that the commercial setting retarder Lucazol F (Nippon Sika Co., Ltd.) was used instead of the PVA-1 used in Example 1. The results are shown in Table 1.

Comparative Example 3 A test was performed in the same manner as in Example 1 except that a 5% aqueous solution of aminotri (methylenephosphonic acid) was used instead of using PVA-1 used in Example 1. The results are shown in Table 1.

Example 9 Inorganic molded article blend; cement: 1, fine aggregate: 1.5, seed stone: 2.5 The inorganic molded article composition having the above composition was cast, and immediately thereafter, a water-soluble composition having a setting retarding effect was obtained. A 10% aqueous solution of polyvinyl alcohol (PVA-1; degree of polymerization: 1700, degree of saponification: 98.5 mol%; PVA-117 manufactured by Kuraray Co., Ltd.) is sprayed on the upper surface of the inorganic molded article composition as a polymer by 10 g / m ^2. (Solid content) was applied. The coating workability at this time was determined according to the following criteria. ○ Very good, Δ slightly uneven, × sagging. After curing in the air for 3 days, washing was carried out by an ordinary method, the finished surface of the upper part of the molded body was observed, and it was judged according to the following criteria. ○ Almost uniform, Δ slightly uneven, × hardened and unwashable The results are shown in Table 2.

Example 10 Instead of using PVA-1 used in Example 9, a 10% aqueous solution of polyvinyl alcohol (PVA-2; polymerization degree 1700, saponification degree 88 mol%; PVA-217 manufactured by Kuraray Co., Ltd.) was used. A test was performed in the same manner as in Example 9 except for using the same. Table 2 shows the results.
Shown in

Example 11 Instead of using PVA-1 used in Example 9, a 5% aqueous solution of polyvinyl alcohol (PVA-3; polymerization degree: 2400, saponification degree: 88 mol%; PVA-224 manufactured by Kuraray Co., Ltd.) was used. A test was performed in the same manner as in Example 9 except for using the same. The results are shown in Table 2.

Example 12 Instead of using PVA-1 used in Example 9, hydroxyethyl cellulose (HEC SP600; Daicel Chemical Industries, Ltd.)
The test was performed in the same manner as in Example 9 except that a 2% aqueous solution was used. The results are shown in Table 2.

Example 13 A test was conducted in the same manner as in Example 9 except that a 2% aqueous solution of sodium carboxymethylcellulose (CMC 1180; manufactured by Daicel Chemical Industries, Ltd.) was used instead of using PVA-1 used in Example 9. Was done. The results are shown in Table 2.

Example 14 The same as Example 9 except that a 3% aqueous solution of methylcellulose (MC) (60SH-4000; manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of using PVA-1 used in Example 9. Was tested. The results are shown in Table 2.

Example 15 Instead of using PVA-1 used in Example 9, an ethylene-vinyl acetate copolymer emulsion (OM-420 manufactured by Kuraray Co., Ltd.)
The test was performed in the same manner as in Example 9 except that 0%, a concentration of 55%, and polyvinyl alcohol as a protective colloid (10%) were used. The results are shown in Table 2.

Example 16 In a glass container equipped with a reflux condenser, a dropping funnel, a thermometer, a nitrogen inlet, and a stirrer, polyvinyl alcohol (PVA-
4, polymerization degree 500, saponification degree 88 mol%, containing mercapto group; 60 g of Kuraray Co., Ltd. M-205), ion-exchanged water 5
40 g was charged and completely dissolved at 95 ° C. Next, after adjusting the pH to 4 with dilute sulfuric acid, 60 parts of methyl methacrylate, 60 parts of n-butyl acrylate, and 0.6 part of n-dodecyl mercaptan were added while stirring at 150 rpm, and the temperature was raised to 70 ° C. after replacement with nitrogen. . The polymerization was started by adding 30 parts of 1% potassium persulfate, and a mixture of 240 parts of methyl methacrylate, 240 parts of n-butyl acrylate, and 2.4 parts of n-dodecyl mercaptan was continuously added over 2 hours. . Three hours after the start of the polymerization, the conversion reached 99.4%, and the polymerization was terminated. Solids concentration 51.7
% Of a stable methyl acrylate / n-butyl acrylate copolymer emulsion was obtained. PVA- used in Example 9
Instead of using 1, methyl acrylate / n-
The test was conducted in the same manner as in Example 9 except that the butyl acrylate copolymer emulsion was used after being diluted to 10%. The results are shown in Table 2.

Comparative Example 4 Instead of using PVA-1 used in Example 9, 5 of citric acid was used.
A test was conducted in the same manner as in Example 9 except that a 10% aqueous solution was used.
The results are shown in Table 2.

Comparative Example 5 A test was conducted in the same manner as in Example 9 except that PVA-1 used in Example 9 was replaced with a commercially available set retarder Lucazol F (Nippon Sika Co., Ltd.). The results are shown in Table 2.

Comparative Example 6 A test was conducted in the same manner as in Example 9 except that a 5% aqueous solution of aminotri (methylenephosphonic acid) was used instead of PVA-1 used in Example 9. The results are shown in Table 2.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

EFFECTS OF THE INVENTION The setting retarder for the surface of an inorganic molded article of the present invention can be washed out at any time after accelerated curing, for example, when an operator's hand is reached, due to an excellent setting delay effect. It is possible, and the washing surface is uniform and uniform. Moreover, by adjusting the concentration of the water-soluble polymer or aqueous emulsion, it is possible to apply by various sprays and the like, and it is possible to uniformly adhere to the formwork surface or the laying surface, etc., so that the application workability is excellent. ing. Due to such features, it can be widely used for application to a formwork surface during concrete casting, or as a surface decoration molding method for producing a cement-based cured product. In addition, the application to the mold surface makes it extremely easy to remove the inorganic molded body such as concrete.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4G053 AA07 DA11 4G055 AA01 BA76 4J002 AA001 BE021 GL00 HA07

Claims (5)

[Claims] 1. A set retarder for the surface of an inorganic molded article comprising a water-soluble polymer or an aqueous emulsion. 2. The setting retarder for the surface of an inorganic molded article according to claim 1, wherein the water-soluble polymer is polyvinyl alcohol. 3. The setting retarder for the surface of an inorganic molded article according to claim 1, wherein the aqueous emulsion is an aqueous emulsion containing polyvinyl alcohol as a protective colloid. 4. The setting retarder for a surface of an inorganic molded article according to claim 1, wherein the inorganic molded article is a cement, mortar or concrete molded article. 5. A method for producing an inorganic molded article, comprising applying a setting retarder comprising a water-soluble polymer or an aqueous emulsion to a mold surface or a laying surface during the production of the inorganic molded article.