JPS6143303B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a cement product with particularly improved shrinkage resistance and water resistance. Specifically, a copolymer resin emulsion (hereinafter simply referred to as emulsion) obtained by emulsion polymerization of ethylene, unsaturated polybasic acid ester, and vinyl acetate to a specific composition under high pressure is used as cement and, if necessary, filler (agent). The present invention relates to concrete, mortar, and other cement products that have particularly improved shrinkage resistance and water resistance when mixed with cement. cement or cement against sand, pebbles,
Cement products, which are formed by adding aggregate such as crushed stone, are widely used in the fields of civil engineering and architecture.
It has drawbacks such as insufficient bending strength, tensile strength, water resistance, shrinkage resistance, crack resistance, abrasion resistance, chemical resistance, etc. Conventionally, in order to improve these drawbacks, methods of mixing in so-called "susa" such as inorganic fibers, synthetic fibers, and vegetable fibers, vinyl acetate resin emulsions, synthetic rubber latexes, acrylic resin emulsions, ethylene vinyl acetate resins, etc. have been proposed. Attempts have been made to incorporate a synthetic resin emulsion such as an emulsion, but each method has advantages and disadvantages and has not yet resulted in a sufficient improvement method. For example, although the mixing of Susa is effective in improving crack resistance, it is essentially not possible to improve other properties such as water resistance, and on the contrary, the mixing causes a decrease in workability and an increase in the cement water ratio. This is not always satisfactory, as it causes a reduction in the quality of various animals, and furthermore, the protrusions cause a scratchy and poor finish. Contamination with vinyl acetate resin emulsion results in significantly poor water resistance due to the lack of essential alkali resistance, and mechanical strength such as adhesive strength, bending strength, and compressive strength is particularly low when cured in water, and crack resistance is rather poor due to contamination. This often leads to deterioration, and there are many problems in putting it into practical use. The inclusion of synthetic rubber latex does not necessarily provide sufficient shrinkage resistance, weather resistance, adhesive strength, etc., and the inclusion of acrylic acid ester resin emulsion results in inferior adhesive strength and bending strength. Among synthetic resin emulsions, ethylene vinyl acetate resin emulsions are said to have relatively superior properties, but they have poor water resistance, shrinkage resistance,
It is difficult to say that crack resistance is necessarily satisfactory, and in order to provide sufficient water resistance, it is necessary to perform waterproof construction such as applying a water-resistant ricin paint. There is still a drawback that the waterproof coating film cannot follow the cracks, causing problems such as tearing and water intrusion. However, as a result of intensive research to improve the above-mentioned drawbacks of cement products, the present inventors have found that by incorporating an emulsion with a specific composition, they have achieved significant improvements in physical properties that cannot be obtained with conventional ethylene vinyl acetate resin emulsions. This resulted in the production of cement products. That is, according to the present invention, as can be easily understood from the high degree of waterproofness and low water absorption, it has greatly improved water resistance, and also exhibits excellent shrinkage resistance. If we consider this together with the excellent bending strength/compressive strength ratio, which is one indicator of crack occurrence, we can obtain a cement product that has the major characteristics of having a high degree of shrinkage resistance and crack resistance. It also has excellent adhesive strength and abrasion resistance on the joint surface, making it possible to obtain an improved cement product without sacrificing conventional physical properties. The composition of the emulsion used in the present invention has an ethylene content of 5 to 25% by weight (hereinafter simply referred to as %).
The content of unsaturated polybasic acid esters is preferably 3 to 20%, preferably 5 to 15%, and the vinyl acetate content is preferably 90 to 70%, preferably 85 to 70%.
within the range of %. If the vinyl acetate content is 90% or more, it will be no different from a vinyl acetate resin emulsion, and if it is less than 70%, there will be disadvantages such as reduced adhesive strength and bending strength. If the content of unsaturated polybasic acid esters is less than 3%, the copolymerization effect will not be sufficient, and if it is more than 20%, although water resistance will be effective, shrinkage resistance will decrease, and furthermore, a good emulsion may not be obtained. This is disadvantageous because manufacturing becomes difficult and the price increases. When the amount of unsaturated polybasic acid ester is copolymerized, it is generally preferable to select a small amount when the amount of ethylene is large, and to select a relatively large amount in the opposite case, taking physical properties such as alkali resistance into consideration. The unsaturated polybasic acid esters used in the present invention are esters or ester salts of unsaturated polybasic organic acids, and more specifically, maleic acid monoesters, maleic diesters, fumaric acid monoesters, Fumaric acid diester, itaconic acid monoester, itaconic acid diester, citraconic acid monoester, citraconic acid diester, aconic acid monoester, aconic acid diester, aconic acid triester, methylene malonic acid monoester, methylene malonic acid diester, and these monoesters These include calcium salts, ammonium salts, and alkali metal salts such as sodium and potassium salts of esters or diesters, and these are not limited to one type, but two or more types may be used in combination. Although the mechanism of action of the present invention is not necessarily clear, there is a correlation between the amount of copolymerization of unsaturated polybasic acid esters and the specific gravity of cement products, and the copolymerization improves film-forming properties, water resistance, and alkali resistance. It is expected that the improvement in water resistance, shrinkage resistance, bending strength, abrasion resistance, etc. of cement products will be significantly improved. The method for producing the emulsion used in the present invention may be substantially the same as that for conventional ethylene vinyl acetate resin emulsions, and it is also advantageous that no special equipment or production method is required. In other words, the emulsion polymerization method is carried out under constant pressure using an autoclave with adjustable internal temperature, and the temperature is usually 0 to 70℃ and the pressure is 10℃.
A condition of ~80Kg/cm ² G is adopted. In producing the emulsion, all known materials such as polymerization catalysts, surfactants, protective colloids, buffering agents, and chain transfer agents can be used. The method of adding monomers such as acid esters and the method of adding polymerization catalysts, emulsifiers, etc. are carried out by appropriately selecting advantageous conditions. Further, vinyl chloride, vinylidene chloride, propylene, butadiene, branched fatty acid vinyl ester having 7 to 12 carbon atoms, acrylonitrile, methacrylonitrile, within the range that does not impair the effects of the present invention,
Vinyl propionate, vinyl butyrate, carbon number 1-8
or other copolymerizable monomers such as acrylic esters, acrylic acid, methacrylic acid, crotonic acid, maleic anhydride, acrylamide, etc. can be copolymerized. Furthermore, the method for producing the cement product of the present invention is no different from the conventional method. In other words, cement or cement with aggregate such as sand, pebbles, crushed stone, etc. is mixed with a predetermined amount of the above-mentioned elbow and the minimum amount of water necessary for the work, and is used for various constructions to produce cement products. It is something. The emulsion to be mixed may be obtained by emulsion polymerization as it is or may be diluted with water if necessary. Although the amount of mixing is not particularly limited, it is preferably several percent or more in order to obtain a sufficient effect. However, if more than necessary is mixed in, the strength and workability will be reduced, and the cost will increase, so it is preferable to select the mixing ratio within the range of about 2 to 30% (solid content/cement ratio). During kneading, antifoaming agents, water retention agents, fluidity improvers, AE agents, water reducing agents, waterproofing agents, swelling agents, foaming agents,
Preservatives, anti-mold agents, anti-rust agents, coloring agents such as pigments,
There is no problem with the combined use of known fillers such as anti-freezing agents, plasticizers, membrane-forming aids, and artificial lightweight aggregates, and with the addition of these to the emulsion in advance. The cement products of the present invention are used for finishing, repairing, waterproofing mortar, or waterproofing on various substrates such as ordinary concrete, lightweight concrete, mortar, gypsum board, PC board, ALC board, slate board, plywood board, various lath boards, and steel boards. Concrete, structural concrete, roads, sidewalks, floors, concrete for bridges, etc. Next, the present invention will be explained in detail by giving examples. [Production of emulsion] In a 20L autoclave equipped with a stirrer and jacket, add polyvinyl alcohol PA to 3.9Kg of water.
-18 (manufactured by Shin-Etsu Chemical Co., Ltd., 4% viscosity 24 centipoise, saponification degree 88 mol%) 60 g, PA-05 (manufactured by Shin-Etsu Chemical Co., Ltd., 4% viscosity 5 centipoise, saponification degree 88 mol%) 190 g, and ferrous sulfate Ammonium 0.05g
and 4.293 kg of vinyl acetate were charged, heated to 55°C, ethylene was injected at a pressure of 35 kg/cm ² G, and 20 g of 0.5% hydrogen peroxide and 5 g of sodium formaldehyde sulfoxylate were added. . then dibutyl maleate for 4 hours.
707g, 2% hydrogen peroxide solution 400g and 5% formaldehyde sodium sulfoxylate solution
Added 100g. After aging for 2 hours, a good emulsion with a solids content of 5.8% and a viscosity of 1780 centipoise was obtained. The copolymer compositions were 17% ethylene, 7% dibutyl maleate, and 76% vinyl acetate. Example 1, Comparative Examples 1 to 2 100 parts of ordinary Portland cement (parts indicate parts by weight, the same applies hereinafter) was mixed with 300 parts of river sand, and then the emulsion obtained above was mixed with 10 parts of the solid content and flowed. An appropriate amount of water was added so that the ratio was 170±5, the mixture was kneaded, and a specimen was molded. For comparison, ethylene vinyl acetate resin emulsion (solid content 55.4
%, ethylene content 20%) in solid content [Comparative Example 1], and a specimen obtained in the same manner except that no emulsion was added [Comparative Example 2] were prepared. . When various properties were measured for each of these specimens, the results were as shown in Table 1. However, *1 to *9 in Table 1 are as follows, respectively. *1 Tensile adhesive strength to concrete sidewalk board *2 JIS R 5201 (1977) *3 JIS A 1404 (1977) *4 JIS A 1129 (1975) *5 JIS A 1174 (1978) *6 JIS K 7204 (1974) Compliant

【table】

[Table] Examples 2 to 6, Comparative Examples 3 to 4 Emulsions having various compositions shown in Table 2 were prepared according to the emulsion manufacturing method used in Example 4. Test specimens were prepared in the same manner as in Example 1 except that these emulsions were used, and various properties were measured. The results were as shown in Table 3. However, the abbreviations used in Table 2 are as follows. VP: Vinyl propionate VAc: Vinyl acetate DEM: Diethyl maleate DBM: Dibutyl maleate BM: Butel maleate DEF: Diethyl fumarate EF: Ethyl fumarate BMA: Butylammonium maleate

【table】

【table】

Claims (1)

[Claims] 1. A copolymer resin emulsion having an ethylene content of 5 to 25% by weight, an unsaturated polybasic acid ester content of 3 to 20% by weight, and a vinyl acetate content of 90 to 70% by weight is mixed into cement. modified cement products.