JPH06100344A - Production of powdery polymer composition - Google Patents

Abstract

PURPOSE:To provide a method for producing a powdery polymer composition containing a hydraulic substance excellent in dispersibility without causing blocking. CONSTITUTION:Polyvinyl alcohol having 500-1000 polymerization degree and >=85% saponification degree in an amount of 5-20wt.% is added to a copolymer, prepared by carrying out the emulsion polymerization of a monomer mixture of 5-30wt.% ethylene with 70-90wt.% vinyl acetate, 1-10wt.% unsaturated carboxylic acid ester and a nonionic emulsifying agent in an amount of 0.1-30wt.% and a protective colloid in an amount of 1 to <5wt.% based on the monomer mixture and having <=5 deg.C film-forming temperature to provide a polymer dispersion having a polymer concentration regulated to 40-50wt.% polymer concentration and the total solid concentration regulated to 45-55wt.%. The obtained polymer dispersion and an aqueous dispersion of a hydraulic substance are simultaneously introduced into a spray-drying tower and spray- dried.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a powdery polymer composition containing a hydraulic substance, which comprises a polymer dispersion and a hydraulic substance. More specifically, to prevent blocking between powdery polymer compositions,
The present invention relates to a method for producing a powdery polymer composition containing a hydraulic substance having excellent dispersibility. Further, its industrial application fields are diverse, such as solid and highly durable concrete, repair materials, floor materials, waterproof materials, adhesives and building materials.

[0002]

2. Description of the Related Art Conventionally, polymer dispersions have been mixed with cement, aggregates, water, etc. to obtain crack resistance, bending strength, mortar, concrete, etc.
It is known to be used for a highly durable mortar and the like having improved impact resistance and adhesiveness. It is also known that a synthetic hydrate is bonded and cured by a polymer dispersion and used as a building material or the like.

However, when the polymer dispersion is mixed with cement, a hydration reaction occurs and the composition hardens. Therefore, when it is applied, it must be prepared on site. Then, in such a case, the polymer dispersion has a problem that the transportation cost is high because it is dispersed in an aqueous system, that it is difficult to handle on site, and that a measurement error easily occurs. As a countermeasure against this, it has been desired to powder the polymer dispersion.

On the other hand, to prevent powdery polymers from blocking during storage, to have good redispersibility in water, and to support various applications such as adhesives, paints, cements and admixtures. It is basically required to have a low film-forming temperature.

However, the polymer dispersion having a low film-forming temperature has various improvements because it is difficult to adhere to the wall of the spray-drying tower during spray-drying or to be blocked during storage to form a powder. Has been added. For example, (1) a method of preparing and adding polyvinyl alcohol and the like (Japanese Patent Publication No. 53-47382), (2) a method of forming a copolymer having a high minimum film-forming temperature in emulsion particles by two-step polymerization (Japanese Patent Publication No. 60- 1900), (3) Method using dry anti-caking agent (Japanese Patent Publication No. 55-50971) and (4) Method using anti-blocking material (Japanese Patent Publication No. 57-139).
137) is known.

However, in (1), the solid content concentration of the polymer dispersion is as low as 20 to 30%, and it is necessary to remove a large amount of water during drying. In (2), it is necessary to take a complicated means of two-step polymerization to obtain an emulsion. In (3), the adhesion of the anti-caking agent to the polymer is not sufficient. Further, in (4), it is necessary to use three kinds of emulsifiers, an anionic emulsifier, a nonionic emulsifier and polyvinyl alcohol, in order to obtain a polymer dispersion.

As a result of various studies to solve the above-mentioned problems, the inventors of the present invention have simultaneously spray-dried a polymer dispersion having a low film-forming temperature, which is obtained by an easy method, and a hydraulic substance. The inventors have found that a powdery polymer composition containing a hydraulic substance having excellent workability and durability can be obtained, and completed the present invention.

[0008]

SUMMARY OF THE INVENTION That is, the present invention relates to ethylene of 5 to 30% by weight, vinyl acetate of 70 to 90% by weight, unsaturated carboxylic acid ester of 1 to 10% by weight, and a nonionic property to the monomer mixture. A degree of polymerization of 500 to 1000 with respect to a copolymer having a film forming temperature of 5 ° C. or less obtained by emulsion polymerization using 0.1 to 3% by weight of an emulsifier and 1 to less than 5% by weight of a protective colloid.
5-20% by weight of polyvinyl alcohol with a saponification degree of 85% or more
In addition, copolymer concentration 40 to 50% by weight, total solids concentration 45 to 55
A method for producing a powdery polymer composition containing a hydraulic substance, which comprises introducing the polymer dispersion in a weight percentage and an aqueous dispersion of the hydraulic substance into a spray drying tower at the same time and performing spray drying.

The present invention will be described in detail below.

The polymer dispersion according to the present invention is desired to have a low minimum film-forming temperature in view of its performance and workability, but if the temperature is 5 ° C. or lower, there is no particular problem in workability. Further, the monomer includes ethylene, vinyl acetate and unsaturated carboxylic acid ester. The unsaturated carboxylic acid ester as used herein is an unsaturated carboxylic acid ester and / or a diester of an unsaturated carboxylic acid, and examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, methyl crotonate, dimethyl itaconate, Examples thereof include dimethyl maleate, dimethyl fumarate, methyl acrylate, ethyl acrylate, propyl acrylate and butyl acrylate.

The composition of the monomer that affects the minimum film forming temperature of the polymer dispersion is such that the minimum film forming temperature is 5 ° C.
It is not particularly limited as long as it is the following, but ethylene content 5 to 30% by weight, vinyl acetate content 70 to 90
Weight percent and unsaturated carboxylic acid ester contents of 1 to 10 weight percent are preferred. If the amount of ethylene and unsaturated carboxylic acid ester is more than this, the bending strength and adhesive strength decrease,
If the amount of vinyl acetate is more than this, the minimum film forming temperature becomes high, and the water resistance and alkali resistance also decrease.

When the polymer dispersion is spray-dried, it is advantageous in terms of energy cost to dry it while keeping the solid content high, but on the other hand, the powder state is poor and the re-emulsification property and the storage stability are poor. There is a tendency. However, by using an emulsifier and a protective colloid as a dispersant when synthesizing the polymer dispersion, it becomes possible to carry out spray drying without a problem even when the solid content concentration is high.

The emulsifier according to the present invention is a nonionic emulsifier and is, for example, one kind or a mixture of two or more kinds of polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether and oxyethylene-oxypropylene block polymer. And, the amount used is appropriate to be 0.1 to 3% by weight with respect to the amount of charged monomers. If the amount of emulsifier used is less than 0.1% by weight, the polymer dispersion becomes mechanically unstable and 3% by weight
If it exceeds, the significant effect on the effect will not be recognized and it may be economically disadvantageous.

The protective colloid according to the present invention has a polymerization degree of 500.
.About.2500, saponification degree 80 to 93%, and one or more kinds of polyvinyl alcohol. Then, the amount of its use is appropriate to be less than 1 to 5% by weight with respect to the copolymer. When the amount of polyvinyl alcohol used is less than 1% by weight, the polymer dispersion is mechanically unstable, and when it is 5% by weight or more, the viscosity of the polymer dispersion becomes high and the powder state after spray drying may deteriorate.

Polymerization of the polymer dispersion according to the present invention can be carried out, for example, by adding monomers in a batch or by charging them all at once.
It is carried out by adding the catalyst at a polymerization temperature of 45 to 75 ° C. By this method, a polymer dispersion having a high solid content concentration can be easily obtained.

The catalyst for polymerizing the polymer dispersion is a redox catalyst commonly used in ethylene / vinyl acetate copolymerization. For example, hydrogen peroxide, persulfates, peroxides such as t-butyl hydroperoxide, formaldehyde sodium sulfoxylate, reducing sulfur oxide salts such as thiosulfuric acid or dithionous acid, and iron sulfate are used. .

When the polymer dispersion is spray-dried, by adding polyvinyl alcohol to the copolymer, the powdery polymer composition having good redispersibility can be dried even at a high tower inlet temperature of the spray-drying tower. Is obtained.

The polyvinyl alcohol according to the present invention preferably has a polymerization degree of 500 to 1000, more preferably 50.
0 to 600, the saponification degree is preferably 85% or more,
More preferably, it is 95% or more. If the degree of polymerization of polyvinyl alcohol is too large, the powdery polymer composition tends to be blocked, and the storage stability and re-emulsification property decrease, and if it is too small, the re-emulsification property of the powdery polymer composition deteriorates. If the degree of saponification is low, the re-emulsification property of the powdery polymer composition will be poor. The amount of polyvinyl alcohol used is preferably 5 to 30% by weight, more preferably 10 to 20% by weight, based on the copolymer. If the amount of polyvinyl alcohol used is greater than this, the clay in the mixture of the polymer dispersion and polyvinyl alcohol will rise too much and the workability will decrease. If the amount is too small, the re-emulsification property of the powdery polymer composition will be poor.

When the polymer dispersion is spray-dried, a hydraulic substance is simultaneously introduced into the spray-drying tower and spray-dried to obtain a powdery polymer composition having excellent storage stability without blocking.

Examples of the hydraulic material according to the present invention include those containing a cementitious material as a main component and / or ultrafine inorganic powder.

As the cementitious substance, various Portland cements such as ordinary Portland cement, early early-strength Portland cement, super early-strength Portland cement, and white Portland cement, mixed cement obtained by mixing these Portland cement with blast furnace slag and fly ash, and ultra-rapid hardening. Cement or alumina cement can be used. Here, as the ultra-rapid cement, there is, for example, fluorine-containing calcium aluminate. Further, low heat-generating cement such as moderate heat cement, blast furnace cement and fly ash cement, and sulfate resistant cement can also be used. The particle size of cementitious material is usually 5 ~
The one having a size of 30 μ is used, but a smaller one or a larger one can be used as long as it has hydraulic properties.

Further, it is also possible to use as a hydraulic substance a rapid hardening material, an expansive material, a high strength admixture and various other admixtures which are usually used in cement concrete. Examples of the quick-hardening material include those containing calcium aluminate as a main component, examples of the expanding material containing calcium sulfaluminate as a main component, and examples of the high-strength admixtures containing anhydrous gypsum as a main component. The particle size of these admixtures is usually 0.5 to 30μ, but
It is possible to use a smaller one or a larger one.

As the inorganic ultrafine powder, particles which are smaller by 1 order, preferably 2 orders than the cementitious substance, and there are no particular restrictions on the components of the ultrafine powder, but those which are readily soluble in water are not suitable. The production method is not particularly limited and may be an ordinary method, but from the viewpoint of economy, those produced by pulverization and classification and those produced as a by-product are preferable. Specifically, finely pulverized products such as blast furnace slag and fly ash, as well as siliceous dust and silica fume, which are by-products during the production of silicon, silicon-containing alloys, zirconia and the like, are suitable. Other,
Clay minerals such as silica gel, opalaceous silica, titanium oxide, aluminum oxide, zirconium oxide, various glasses, bentonite and other clay minerals, calcined products thereof, amorphous aluminosilicate, chromium oxide, and ultrafine powder of activated carbon can also be used.

An appropriate amount of these hydraulic substances used is 31 to 99 parts by weight based on 100 parts by weight of the solid content of the polymer dispersion. If the amount of the hydraulic substance used is less than 31 parts by weight, the effect of the hydraulic substance as an admixture of the hydraulic substance such as fluidity improvement, strength increase, denseness improvement, shrinkage reduction and crack resistance is small, and exceeds 99 parts by weight. And the redispersibility of the polymer dispersion is poor, and the crack resistance and adhesiveness are poor.

As the spray drying method, a method in which a polymer dispersion premixed with polyvinyl alcohol and an aqueous dispersion of a hydraulic material are sprayed at the same time, but the introduction routes are sprayed into the drying tower using different spray nozzles, Alternatively, a method in which a mixed slurry composed of a hydraulic substance and a polymer dispersion is prepared in advance and the slurry is sprayed into a drying tower with a two-fluid nozzle or a rotating disk can be used.

The aqueous dispersion of the hydraulic material in the present invention is a dispersion of the hydraulic material in water or a dispersion of the hydraulic material in a polymer dispersion.

[0027]

The present invention will be described in more detail with reference to the following examples. Example 1

A pressure resistant reactor equipped with a stirrer was charged with the following composition mixture. Water 400 parts by weight Vinyl acetate 430 parts by weight n-Butyl acrylate 15 parts by weight Emulsifier (Emulgen-913, manufactured by Kao Soap Co., Ltd.) 4 parts by weight Protective colloid (PVA-05, manufactured by Denki Kagaku Co., Ltd.) 20 parts by weight sulfuric acid Iron 0.01 parts by weight Sodium formaldehyde sulfoxylate 0.1 parts by weight Sodium acetate 0.5 parts by weight While stirring this solution well, ethylene was blown twice to remove air in the reaction can, and ethylene was pressurized to 60 parts. The reaction mixture was heated and heated, and when the internal temperature reached 60 ° C., a 5 wt% aqueous solution of ammonium persulfate was added to start the reaction. After that, the catalyst was continuously added so that the temperature inside the reaction vessel was kept constant at 60 ° C., and the polymerization was completed after 6 hours. During this period, the amount of the ammonium persulfate aqueous solution added was about 10 parts.
As a result, the copolymer dispersion with a solid content of about 56% by weight was about
930 copies were obtained.

Example 2 The polymer dispersion obtained by adding polyvinyl alcohol to the copolymer dispersion obtained in Example 1 and a hydraulic substance were simultaneously introduced into a spray drying tower for drying. The spray-drying system used was a three-fluid nozzle system, and a product name "Nippirosa-type spray dryer of West Germany" manufactured by Nippon Dairy Machinery Co., Ltd. was used as a spray-drying device.

That is, a polymer dispersion produced by adding an 18% by weight aqueous solution of polyvinyl alcohol having a degree of polymerization of 550 and a degree of saponification of 98% to the copolymer dispersion obtained in Example 1 was discharged from a central tube of a three-fluid nozzle. It was discharged at a rate of 2.5 to 4.0 kg / h, and slurries prepared by diluting blast furnace slag (average particle size of 1.0 μ by gas adsorption method) as a hydraulic substance from the outer pipe to 20 wt% with water of 2.5 to 4.0 kg / h were used. The compressed air was discharged from the outermost tube at a rate of 2.0 to 3.0 kgf / cm2.
Further, the temperature inside the dryer was 100 ° C. near the fluid nozzle and 130 ° C. near the fluid nozzle.
Table 1 shows each condition and the properties of the obtained powdery polymer composition.

[0031]

[Table 1]

[0032]

According to the method of the present invention, a powdery polymer composition containing a hydraulic substance and having excellent dispersibility in which blocking between powdery materials does not occur can be obtained. Moreover, this powdery polymer composition can be stored for a long period of time. Furthermore, by using the hydraulic substance-containing powdery polymer composition produced according to the present invention as an admixture for cement, a solid cement hardened product having excellent durability can be obtained.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C09J 131/04 JCH 6904-4J JCJ 6904-4J // C09J 1/00 AAA 6770-4J (72) Inventor Nobuyoshi Nakajima 6 Goi Minamikaigan, Ichihara, Chiba Denki Kagaku Kogyo Co., Ltd. (72) Inventor Kazuyuki Shimoda 6 Goi Minami Kaigan Ichihara, Chiba Denki Kagaku Kogyo Co., Ltd. Chiba (72) Inventor Hideki Hirano 6 Goi Minami Coast, Ichihara City, Chiba Denki Kagaku Kogyo Co., Ltd. Chiba Factory

Claims (1)

[Claims] 1. Ethylene 5 to 30% by weight, vinyl acetate 70 to
90% by weight, 1 to 10% by weight of unsaturated carboxylic acid ester, and 0.1 to 0.1% of a nonionic emulsifier with respect to the monomer mixture.
For a copolymer having a film-forming temperature of 5 ° C. or less, which is obtained by emulsion polymerization using 3% by weight and a protective colloid of 1 to less than 5% by weight,
Polyvinyl alcohol having a degree of polymerization of 500 to 1000 and a saponification degree of 85% or more is added in an amount of 5 to 20% by weight, and a copolymer concentration is 40 to 50% by weight,
Polymer dispersion containing a total solid content of 45 to 55% by weight, and an aqueous dispersion of a hydraulic substance are simultaneously introduced into a spray drying tower, and spray-dried. A hydraulic substance-containing powdery polymer composition characterized by being spray-dried. Method of manufacturing things.