JPH037619B2 - - Google Patents

Description

[Detailed description of the invention]

In the present invention, an emulsion obtained by mixing a specific styrene-unsaturated carboxylic acid ester copolymer emulsion and a specific ethylene-vinyl acetate copolymer emulsion in a specific ratio is mixed into a cement composition, and water resistance ( water absorption/permeability), scratch resistance,
This invention relates to a cement composition with improved adhesive properties. Currently, cement compositions used in the architecture and civil engineering fields have a wide variety of applications, but the common performance requirements for these applications are workability (kneadability, coatability), water resistance (water absorption, Examples include water permeability), scratch resistance, and efflorescence resistance. Particularly recently, the method of applying a thin coat of cement mortar as a base preparation material for concrete surfaces has become popular, and the above performance is particularly required. BACKGROUND ART Conventionally, methods have been proposed for modifying cement compositions by mixing synthetic resin emulsion or synthetic rubber latex as an admixture into cement, sand, and other aggregates. For example, in Japanese Patent Publication No. 53-35816,
It has been shown to incorporate into cement compositions polymerized styrenic unsaturated carbon ester-acrylic acid or glycidyl methacrylate copolymer emulsions using nonionic surfactants in the HLB range of 14 to 19.5. Also, JP-A-54-43285
In the publication, unsaturated carboxylic acid ester and styrene having glass transition temperatures of -10°C to +20°C and -10°C to +10°C are polymerized in two stages in the presence of a nonionic emulsifier, and can be used for cement mixing. shown. Furthermore, for example, Japanese Patent Publication No. 47-33054 discloses that an ethylene-vinyl acetate copolymer emulsion using polyoxyethylene nonyl phenyl ether as an emulsifier is mixed into a cement composition. Furthermore, in Japanese Patent Publication No. 19913-1983, it is disclosed that a saturated monocarboxylic acid vinyl ester copolymer emulsion represented by ethylene-vinyl acetate with polyvinyl alcohol as a protective colloid is mixed into a cement composition. Publication No. 25406 discloses that a cement composition is mixed with an ethylene-vinyl acetate branched fatty acid vinyl ester copolymer emulsion using polyvinyl alcohol and polyoxyethylene octyl phenyl ether as an emulsifier.
-27370 discloses a cement composition containing an ethylene-vinyl acetate copolymer emulsion in which hydroxyethyl cellulose with an added mole number of ethylene oxide of 1.5 to 2.5 is used as a protective colloid and polyoxyethylene nonyl phenyl ether is used as an emulsifier. In Japanese Patent Publication No. 55-19913 and Japanese Patent Application Laid-Open No. 56-11937, ethylene-vinyl acetate-vinyl chloride copolymer emulsion using polyvinyl alcohol or polyvinyl alcohol and a nonionic emulsifier is mixed into a cement composition. What to do, Special Public Service 1977-
19914 discloses that an ethylene-saturated monocarboxylic acid vinyl ester-methyl methacrylate copolymer emulsion using polyvinyl alcohol or polyvinyl alcohol and a nonionic emulsifier, such as polyoxyethylene nonyl phenyl ether, is mixed into a cement composition; The same thing is disclosed in Japanese Patent Application Laid-open No. 55-85444. However, even cement compositions containing these synthetic resin emulsions are not satisfactory in terms of water resistance (water absorption, water permeability), scratch resistance, adhesion, etc. In view of the above-mentioned circumstances, the present inventors have conducted various studies aimed at improving the drawbacks of cement compositions as described above. - Discovered that water resistance (water absorption, water permeability), scratch resistance, and adhesion can be improved by incorporating an emulsion made by mixing a vinyl acetate copolymer emulsion in a specific ratio into a cement composition. This led to the present invention. That is, the present invention provides (A) a styrene-unsaturated carboxylic acid ester copolymer containing 1 to 15 parts by weight of polyvinyl alcohol per 100 parts by weight of resin solid content of the copolymer emulsion, and (B) polyvinyl alcohol. 1 to 15 parts by weight per 100 parts by weight of resin solids in the copolymer emulsion, and HLB
An ethylene/vinyl acetate copolymer emulsion containing 0.1 to 10 parts by weight of a higher fatty acid ester of a polyhydric alcohol having a polyhydric alcohol of 10 or less is mixed with the resin solid content of (A) and (B).
This is a modified cement composition obtained by mixing an emulsion blended with a ratio of 5:95 to 70:30 into a cement composition. This composition is a cement composition that has extremely low water absorption, excellent waterproof properties, and extremely high adhesive strength. That is, according to the present invention, when used as a groundwork preparation cement mortar for buildings, a cement mortar for repairs, a cement mortar for tiling, or a repair mortar for civil engineering, it not only enhances the adhesion to the base, but also improves the adhesion of conventional cement compositions. It is possible to obtain a cement composition in which the water absorption and waterproof properties, which were disadvantageous, are greatly improved, and which do not cause cracking.
It is possible to obtain a cement composition for surface treatment which has good coating properties and does not peel or fall off. In the present invention, the styrene-unsaturated polycarboxylic acid ester copolymer emulsion is a polymer having a glass transition temperature (Tg) of -10 to +20°C and containing styrene or α-methylstyrene with the general formula

It is a copolymer emulsion with an unsaturated carboxylic acid ester represented by the formula: (wherein R is a hydrogen atom or a methyl group, and R' is an alkyl group having 1 to 8 carbon atoms), and is represented by the general formula Representative examples include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, and 2-ethylhexyl esters of acrylic acid and methacrylic acid. These may be used alone or in combination of two or more. Furthermore, depending on the case, a monomer that can be copolymerized with these monomers, based on a total of 100 parts by weight,
For example, acrylonitrile, acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, acrylamide, N-methylolacrylamide,
N-butoxymethylacrylamide, glycidyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, sodium acrylic sulfonate, sodium vinyl sulfonate, 2-acrylamido-2-methylpropanesulfonic acid, etc. in an amount of less than 10 parts by weight. May be used. The ethylene-vinyl acetate copolymer emulsion in the present invention has a polymer Tg of -10 to +20.
In some cases, other monomers that can be copolymerized with vinyl acetate, such as vinyl esters other than vinyl acetate, vinyl chloride, (meth) ) Acrylic acid ester may be used in an amount of less than 50 parts by weight, and further acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, acrylamide, N-methylol acrylamide, N-butoxymethyl acrylamide, glycidyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxyethyl acrylate, sodium allylsulfonate, sodium vinylsulfonate, 2-acrylamide-2
-Methylpropanesulfonic acid or the like may be used in an amount of less than 10 parts by weight. The polyvinyl alcohol used in the present invention has a saponification degree of 70 to 99.5 mol% and an average polymerization degree of approximately 200 to 99.5 mol%.
2700 is preferably used. Furthermore, modified polyvinyl alcohol obtained by modifying the above-mentioned polyvinyl alcohol with carboxylic acid, sulfonic acid, glyoxal, etc. can also be used. These polyvinyl alcohols are preferably used in an amount of 1 to 15 parts by weight based on 100 parts by weight of the resin solid content of the styrene-unsaturated carboxylic acid ester copolymer emulsion and the ethylene-vinyl acetate copolymer emulsion. More preferably, it is 1.5 to 10 parts by weight. If the amount is less than 1 part by weight, a stable emulsion cannot be obtained, and if the amount exceeds 15 parts by weight, the water resistance will be poor. Further, the higher fatty acid ester of polyhydric alcohol used in the ethylene-vinyl acetate copolymer emulsion must have an HLB of 10 or less, preferably 8 or less, more preferably 6 or less;
Anything over 10 will not produce the desired effect.
The polyhydric alcohols mentioned here include ethylene glycol, propylene glycol, butanediol, pentanediol, glycerin, erythritol, pentaerythritol, arabite, sorbitol, sorbitan, mannitol, mannitan, diethylene glycol, diglycerin, taglycerin, dipropylene glycol, 1, 2, 3 butanetriol, etc., and these mono, di, tri, tetra,
Higher fatty acid esters such as Venta are used. Higher fatty acids include saturated and unsaturated fatty acids, including oleic acid, linoleic acid,
Linoleic acid, capric acid, pelargonic acid, capric acid, lauric acid, tridecanoic acid, myristic acid, bentadecanoic acid, palmitic acid, margaric acid, stearic acid, nonadecanoic acid, arachidic acid,
Examples include hebenic acid, ω-cyclohexyl fatty acid, ω-phenyl fatty acid, ω-cyclopentenyl fatty acid, oxyfatty acid, abietic acid, and tall oil fatty acid. As long as the HLB of the higher fatty acid ester of these polyhydric alcohols is 10 or less, it may be an adduct of polyethylene oxide. Specifically, sorbitan monooleate, sorbitan sesquiolate, sorbitan monostearate, sorbitan monopalmitate, sorbitan monolaurate, sorbitan trioleate, sorbitan tritol oil fatty acid ester, sorbitan monotol oil fatty acid ester, and sorbitan castor oil. ether, stearic acid monoglyceride,
Lauric acid monoglyceride, oleic acid monoglyceride, polyglycerin laurate, polyglycerin stearate, pentaerythritol monostearate, and polyethylene glycol dilaurate, polyethylene glycol distearate, polyethylene glycol dioleate, polyethylene glycol monostearate with HLB 10 or less, Examples include esters of higher fatty acids of polyethylene glycol such as polyethylene glycol monolaurate and polyethylene glycol monooleate. If the amount of these is less than 0.1 parts by weight based on the resin solid content of the ethylene-vinyl acetate copolymer emulsion, there will be no improvement effect, and if it exceeds 10 parts by weight, the stability of the emulsion will be impaired, and the cement composition This is not preferable because the adhesion strength decreases. The amount of higher fatty acid ester of polyhydric alcohol added is preferably 0.2 to 8 parts by weight, more preferably 0.3 to 6 parts by weight. What is important in the present invention is that in the case of a styrene-unsaturated carboxylic acid ester copolymer emulsion, in addition to polyvinyl alcohol, a small amount of an anionic surfactant or nonionic surfactant that is normally used in emulsion polymerization may be used. However, for ethylene/vinyl acetate copolymer emulsion, nonionic emulsifiers used in general emulsion polymerization such as polyoxyethylene nonyl phenyl ether, polyoxyethylene alkyl ether, or block copolymers of polyoxyethylene and polyoxypropylene are used. Even if the emulsifier has a low HLB such as a combination emulsifier, and even if the HLB is at the same level as a general emulsifier, the effect of the present invention will be lost, so it cannot be used.
In the present invention, it is necessary that the ester is a higher fatty acid ester of a polyhydric alcohol and has an HLB of 10 or less. The method for producing the ethylene-vinyl acetate copolymer emulsion used in the present invention is not particularly limited, but for example, ethylene, Obtained by emulsion polymerization of vinyl acetate and other monomers as necessary in an aqueous medium by a conventional method, and emulsion polymerization of the above monomer in an aqueous medium by a conventional method in the presence of polyvinyl alcohol. HLB in emulsion
A method of mixing higher fatty acid esters of polyhydric alcohols having a polyhydric alcohol of 10 or less is preferably employed. In the present invention, the blend ratio of the styrene-unsaturated carboxylic acid ester copolymer emulsion (A) and the ethylene-vinyl acetate copolymer emulsion (B) per resin solid content is (A):(B) 5: The ratio of (A) is 95 to 70:30, preferably 10:90 to 60:40. If (A) is less than this range, the adhesion will be poor, and if it is more than this, the water absorption will be poor. Also
If (B) is less than this range, the water absorption property will be poor, and if it is more than this range, the adhesive property will be poor and the purpose cannot be achieved. The amount of the mixed emulsion of emulsions (A) and (B) to be added to the cement composition is not particularly limited, but the amount generally used for each purpose is sufficient. That is, since economic efficiency is important in cement compositions, it is appropriate to add 3 to 100 parts by weight of the emulsion in terms of solid content per 100 parts by weight of cement in the cement composition. Further, since the effects of the present invention can be achieved by separately mixing the emulsions (A) and (B) with cement, this is also included within the scope of the present invention. EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto. Example 1 Resin solid content 40.2% (same as below weight %) containing 8 parts of sulfonic acid-modified polyvinyl alcohol with saponification degree of 88 mol % (same as below weight) and 0.2 part of sodium polyacrylate per resin solid content
Styrene-butyl acrylate copolymer emulsion (A') at Tg 3°C and resin solids content 56.1 parts containing 4.5 parts of polyvinyl alcohol with saponification degree of 88 mol% and 1.0 parts of sorbitan trioleate (HLB, 1.8) per resin solid content %, Tg0℃ ethylene-vinyl acetate copolymer emulsion (B') was mixed with 30 parts of (A') and 70 parts of (B') per resin solid content.
A homogeneous and stable emulsion was obtained. This emulsion was prepared with a resin solid content of 45%, 100 parts of cement,
100 parts of powder uniformly mixed with 100 parts of Silica Sand No. 7 and 0.2 parts of Hymetrose 90SH4000 (manufactured by Shin-Etsu Chemical Co., Ltd.)
1 part and 25 parts of water were added to obtain a cement mortar composition which was uniformly kneaded. This cement mortar composition was tested for normal adhesive strength and water absorption according to the cement filler evaluation method of the Housing and Urban Development Corporation.
The results are shown in the table. Example 2 The same procedure as in Example 1 was carried out except that (A') was changed to 60 parts and (B') was changed to 40 parts. The results are shown in the table. Example 3 Resin solid content containing 30 parts of (A') of Example 1, 4.8 parts of polyvinyl alcohol with a degree of saponification of 88 mol%, and 2.0 parts of sorbitan trioleate.
A cement composition was obtained by mixing 70 parts of 53.2% ethylene-vinyl acetate-vinyl chloride copolymer emulsion (B'') with a Tg of 5°C, and in the same manner as in Example 1.
I conducted a test. The results are shown in the table. Comparative Example 1 A cement composition was obtained and tested in the same manner as in Example 1 except that only (A') was used as the emulsion. The results are shown in the table. The resin solid content was 40.2%, and the test was conducted by adding 11.2 parts and 23.8 parts of water to 100 parts of powder as a cement mortar composition. Comparative example 2 (B′) without using (A′) as emulsion
A cement composition was obtained and tested in the same manner as in Example 1, except that only 10% of the cement composition was used. The results are shown in the table. Comparative example 3 (B″) without using (A′) as emulsion
A cement composition was obtained and tested in the same manner as in Example 3, except that only 10% of the cement composition was used. The results are shown in the table. Comparative Example 4 80 parts of (A') and 20 parts of (B') in Example 1 were mixed and used. However, this emulsion had a resin solid content of 42.6%, and a trial run was conducted by adding 1.5 parts and 24.5 parts of water to 100 parts of powder as a cement mortar composition. The results are shown in the table. Comparative Example 5 800 parts of (A') and 20 parts of (B'') of Example 3 were mixed and used. However, this emulsion had a resin solid content of 42.3% and a cement mortar composition of 100 parts of powder. The test was carried out by adding 10.6 parts of water and 24.4 parts of water.The results are shown in the table.

【table】

Claims (1)

[Claims] 1 (A) A styrene-unsaturated carboxylic acid ester copolymer emulsion containing 1 to 15 parts by weight of polyvinyl alcohol per 100 parts by weight of the resin solid content of the copolymer emulsion, and (B) a copolymer emulsion containing polyvinyl alcohol. An ethylene/vinyl acetate copolymer emulsion containing 1 to 15 parts by weight per 100 parts by weight of resin solids and 0.1 to 10 parts by weight of a higher fatty acid ester of a polyhydric alcohol with an HLB of 10 or less is added to (A). A modified cement composition obtained by mixing into a cement composition an emulsion blended so that the weight ratio of the resin solid content to that of (B) is 5:95 to 70:30.