JPH0248449A - Cement composition - Google Patents

Abstract

PURPOSE:To obtain the title composition excellent in flexural and compressive strength and adherability to base materials and long in pot-life by incorporating cement with an admixture comprising a specific sulfonated melamine resin and an aqueous dispersion of a specific emulsion polymerization product. CONSTITUTION:An admixture comprising (A) a polymer aqueous dispersion (pref. acrylic, acrylic-styrene-based or SBR-based emulsion polymerization product) <=30 deg.C in polymer glass transition temperature, prepared by emulsion polymerization of an alpha,beta-ethylenic unsaturated monomer and (B) a sulfonated melamine resin, i.e., a melamine sulfonate HCHO condensate >=100000 in weight- average molecular weight, prepared, e.g., by reaction between an amino group- contg. substance consisting mainly of melamine, HCHO and an sulfite in an aqueous medium followed by pH adjustment, in the weight ratio (on a solid bases) A/B=(20/80) to (99/1) is incorporated into cement.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cement composition that provides cement mortar with extremely excellent physical strength and adhesion to various substrates.

[Problems to be solved by conventional techniques and inventions] Civil engineering;
In the construction field, there is a method of improving mortar by mixing emulsion polymers such as polyvinyl acetate emulsion, acrylic emulsion, other synthetic resin emulsion, and SBR latex as admixtures with cement, sand, and other aggregates. It has been proposed and put into practical use.

From the viewpoint of workability, these emulsion polymers usually contain large amounts of emulsifiers and protective colloids in order to prolong the pot life (hereinafter abbreviated as "pot life") of mortar when mixed with cement. ing. However, mortar mixed with these materials has high air propagation properties, and although the bending strength of the cured product is considerably improved, the compressive strength is not significantly improved.Furthermore, the adhesion to the base material is also significantly improved on concrete surfaces. However, there were drawbacks such as the adhesion to smooth substrates such as steel plates and ceramic tiles not being sufficiently improved.

[Means to solve the problem]

In view of the advantages and disadvantages of the conventional technology, the present inventors have discovered that when mixed with cement, the pot life is long, both bending and compressive strength are significantly improved, and the adhesion to various substrates is also excellent. As a result of intensive research on the ideal admixture, we found that an admixture containing a specific ratio of an emulsion polymer with a specific polymer glass transition temperature and a formaldehyde condensate of melamine sulfonate with a specific molecular weight was extremely superior. Discovered that it has properties as a cement admixture,
This led to the present invention.

That is, in the present invention, the glass transition temperature of the polymer obtained by emulsion polymerization of α,β-ethylenically unsaturated monomer is 30°C.
The following polymer aqueous dispersion (a) and a formalin condensate (b) of melamine sulfonate having a weighted average molecular weight of 100,000 or more are (a): value) = 20:80 to 99:1 (
This invention relates to a cement composition in which an admixture having a solid content ratio (weight/solid content) is blended into cement.

Polymer aqueous dispersion, which is the main component of the admixture of the present invention (
Hereinafter, it will be abbreviated as "emulsion polymer". ) The α,β-ethylenically unsaturated monomer that is a component during emulsion polymerization includes, for example,
Methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, 1so-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, etc. (Meth)acrylic acid esters; esters of maleic acid, fumaric acid, and itaconic acid; monobasic acids such as acrylic acid, methacrylic acid, vinylsulfonic acid, and vinyltoluenesulfonic acid, and their salts; itaconic acid and fumaric acid , unsaturated dibasic acids such as maleic acid and their half esters, salts Amides of α,β-ethylenically unsaturated acids such as niacrylamide, methacrylamide, maleic acid amide; N-methylolacrylamide or methacrylamide, noacetone Substituted amides of unsaturated carboxylic acids such as acrylamide; vinyl esters such as vinyl acetate, vinyl propionate, vinyl tertiary carboxylate; aromatic vinyl compounds such as styrene and vinyltoluene; heterocyclic vinyl compounds such as vinylpyrrolidone; Vinyl chloride, acrylonitrile, vinyl ether, vinyl ketone, vinyl amide, etc.; Vinylidene halide compounds such as vinylidene chloride, vinylidene fluoride; α-olefins such as ethylene and glopyrene; Tzenes such as butadiene; noaryl phthalate, divinylbenzene, allyl Acrylate, trimesterol glo!
Examples include monomers having two or more unsaturated bonds in one molecule, such as trimethacrylate, which may be used alone or as a mixture of two or more.

The combination of these monomers can improve the saponification resistance of acrylic, acrylic-styrene, SBR, saran, vinyl acetate, and vinyl acetate, as well as ethylene, (meth)acrylic acid ester, versatile vinyl ester, etc. Various emulsion polymers such as modified vinyl acetate-based emulsion polymers can be obtained by polymerization, but vinyl acetate-based ones are not preferred in consideration of saponification resistance when mixed with cement. Furthermore, considering the saponification resistance and the affinity with cement, the emulsion polymer of the present invention may include acrylic, acrylic-styrene,
SBR emulsion polymers are preferred.

These emulsion polymers can be obtained by carrying out conventional emulsion polymerization under normal pressure or under increased pressure.

Examples of the emulsifier used in this case include commonly used anionic emulsifiers, nonionic emulsifiers, and canon-type emulsifiers. Examples of protective colloids include nonionic water-soluble polymers such as polyvinyl alcohol and hydroxyethyl cellulose, and polymer electrolytes. These emulsifiers and protective colloids are each used singly or as a mixture of two or more, but it is desirable to use them in as small a quantity as possible in consideration of foaming and adhesive properties when mixed with cement, and it is usually a single filter. 0.1 of the total mass amount
It is preferably about 8% by weight.

In addition, a polymerization initiator is used during polymerization, and there are no particular restrictions on this, but representative examples include water-soluble inorganic peroxide,
These include persulfates, organic peroxides, and azo compounds.

The emulsion polymer thus obtained is roughly classified into anionic, nonionic, and cationic types depending on the charge of the particles. In consideration of miscibility, it is preferable to refrain from using cationic types.

Furthermore, the glass transition temperature of the emulsion polymer is 30°C.
It is necessary that the following is true. If the temperature exceeds 30°C, it is difficult to impart flexibility to the cement, and a temperature range of +15 to -30°C is preferred.

Next, a formalin condensate of melamine sulfonate having a weight average molecular weight of 100,000 or more (hereinafter abbreviated as "sulfonated melamine resin"), which is another main component of the admixture of the present invention, will be explained.

Using a sulfonated melamine resin with a similar basic structure, the average molecular weight of melamine was 5.
,000 to 50,000 is a special public service issued in 1977-139.
No. 9, JP-A-57-100959, JP-A-Sho 5
These are proposed in Japanese Patent No. 9-43012, etc., and these are cement dispersants, so-called water-reducing agent compositions, whose main component is a sulfonated melamine resin.

However, the sulfonated melamine resin of the present invention has a molecular weight of io
It has an extremely high molecular weight of more than o, ooo, and has almost no cement dispersibility in itself.

As a method for producing a sulfonated melamine resin, for example, an amino group-containing substance containing melamine as a main component, formaldehyde, and a sulfite are mixed in an aqueous medium at a temperature of -10 or higher and a temperature of 60 to 8.
The reaction was carried out at 0°C for 0.5 to 6 hours (preliminary reaction), and then the - of the reaction mixture was adjusted to 3.5 to 6.5, and the temperature was adjusted to 20 to 7.
After reacting at 0° C. for 1 to 10 hours (post-stage reaction), there is a method in which the - of the reaction mixture is adjusted to 7 to 13 and then cooled.

At this time, the amino group-containing substance whose main component is melamine is melamine alone or melamine and 20%
It is a mixture with an amine-containing compound such as urea, guanamines, nonanamide, thiourea, etc. in a proportion of ft% or less. Examples of formaldehyde include formalin and paraformaldehyde, and examples of sulfites include sodium chloride, ammonium sulfite, sodium bisulfite, ammonium bisulfite, and sodium pyrosulfite.

In the above-mentioned production process, the alkaline substances used to increase the P content of the reaction mixture at the beginning of the first stage reaction (methylolation and sulfomethylenation reaction process) and the second stage reaction (condensation reaction process) are caustic powder, Common alkaline substances such as caustic potash and aqueous ammonia are conveniently used, but caustic soda is particularly preferred from the viewpoint of economy and the like. As the acidic substance used to lower the - of the reaction mixture between the first and second reactions, common acids such as sulfuric acid, nitric acid, hydrochloric acid, amidosulfonic acid, phosphoric acid, formic acid, and p-toluenesulfonic acid can be used. However, since the base of such acids remains in the reactants, the use of substances that have a negative effect on cement hardening or are highly toxic should be avoided; for example, hydrochloric acid, which corrodes iron, should not be used. It's good to hold back.

By the way, the weight average molecular weight as used in the present invention is 100.0.
In order to obtain a sulfonated melamine resin with a high molecular weight of 0.00 or more, (1) the subsequent reaction (condensation reaction step) of the above-mentioned manufacturing process is carried out for a long time to increase the molecular weight; or (2)
By adjusting the stoichiometric amounts of the amino groups of the amino group-containing substance containing melamine as a main component, the sulfite groups of the sulfite, and formaldehyde, the melamine molecules contained in the reaction system of the first stage reaction can be adjusted. A crosslinking component (hereinafter abbreviated as "polymethylolmelamine") in which three or more of the hydrogen atoms of the six amine groups are substituted with methylol groups is produced, and in the subsequent reaction (condensation reaction step) Partially made into Kurihashi to increase the molecular weight, or (3)
There are various methods such as separately synthesizing the above-mentioned polymethylolmelamine, adding it to the reaction system before the second stage reaction, and partially crosslinking it in the second stage reaction to increase the molecular weight.

The molecular weight of the sulfonated melamine resin thus obtained is 1.
If it is less than 00,000, not only will the bending and compressive strength of the hardened cement made by mixing the emulsion polymer with the admixture, the compressive strength, and the adhesion to various substrates decrease, but also the admixture will deteriorate when the admixture is mixed with the cement. Since the miscibility is also poor, the weight average molecule t of the sulfonated melamine resin used in the present invention is ioo,
It needs to be more than ooo. The higher the molecular weight of the sulfonated melamine resin, the better the physical strength of the mixed cement hardened product, but if the molecular weight is too high, there are disadvantages such as the viscosity of the resin water bath becoming too high. A range of oooo is preferred, and a range of 200,000 to 500.00Of is more preferred.

In the present invention, the above-mentioned multiplication polymer (a) and the high molecular weight sulfonated melamine resin (b) are mixed in a solid weight ratio of (a):(b)=20:80 to 9921. It is preferable to mix it with More preferably 30 near 0 to 97:
If the amount of sulfonated melamine resin in the admixture is less than 1, the bending and compressive strength of the hardened cement obtained by mixing the resin will not be sufficiently improved, and the miscibility (fluidity) during mixing will be poor. , pot life) are not sufficiently improved, and conversely, if the weight exceeds 80%, although bending and compressive strength are sufficiently improved, adhesion to various substrates is not sufficiently improved, which is not preferable.

Furthermore, if the emulsion polymer and the sulfonated melamine resin are separately blended into cement, the effects of the present invention will not be achieved at all. Therefore, either a pre-blended product of the emulsion polymer and the sulfonated melamine resin is prepared, the sulfonated melamine resin is used as a protective colloid during polymerization of the emulsion polymer, or the sulfonated melamine resin is placed in a separate container and both are combined immediately before use. It is necessary to blend the

In the present invention, when a high molecular weight sulfonated melamine resin is mixed with an emulsion polymer, it is adsorbed onto the particle surface of the emulsion polymer, as if the functional group density of the emulsion polymer had become extremely high, resulting in poor dispersibility. It is presumed that the cement composition will exhibit excellent physical properties due to the mutual effect of the two.

The proportion of the admixture used in the present invention to be mixed with cement is preferably 3 to 50 parts by weight, more preferably 5 to 30 parts by weight, in terms of solid content, per 100 parts by weight of cement. If it is less than 3 parts by weight, the various physical properties of the hardened cement product will not be sufficiently improved, and if it exceeds 50iii parts, the physical strength of the hardened cement product will deteriorate, which is not preferable.

As the cement, portland cement, mixed cement such as blast furnace slag cement, alumina cement, etc. can be used, but portland cement is particularly preferred. Other fine aggregates such as sand and silica sand, coarse aggregates such as gravel, shrinkage softeners such as Flyanyu and C8A (manufactured by iKikagaku Co., Ltd.),
Foaming agents such as aluminum powder, water retention agents such as methylcellulose, lightweight materials such as perlite and foamed melamine, fibers such as polyvinyl alcohol fibers, carbon fibers, and steel fibers, known AE agents (air entraining agents), AE water reducing agents, All-C, such as a high performance water reducing agent, can be used as long as it does not significantly impede the advantages of the present invention.

〔Example〕

Next, the present invention will be explained by reference examples and examples.

Below, unless otherwise specified, all parts and weights are based on weight.

Reference Example 1 (Preparation of sulfonated melamine resin) 49.0 parts of water and 42.0 parts of melamine (per 1.0 g of amino group) were placed in a reaction vessel with a thermometer, stirrer, and reflux condenser with stirring. , 81.0 parts of 37% formalin (per 1.0 g, 26.0 parts of sodium bisulfite (0.25 g/m), and further 2.2 parts of caustic soda -'i
It was adjusted to 13.1.

Next, the temperature in the reaction system was raised to 75°C, and at the same temperature, 2,
It was held for 5 hours.

After that, the total temperature in the reaction system was brought to 55°C, and 7.1 parts of concentrated sulfuric acid diluted with 100.0 parts of water was added dropwise over 1 hour.
-4.4. If the pH was further maintained at 1 hour at the same temperature, the reaction mixture became viscous (15.000 cps at 25°C).
)', At this point, 150.0 parts of water was added, and the mixture was further maintained at the same temperature for 3 hours.After that, 5.0 parts of caustic soda and 70.0 parts of water were added, and the mixture was cooled to room temperature. The resin is a colorless translucent liquid with a solid content of 20.0% and a viscosity of 180.
cps (25℃), pH 11.2, weight average molecule t3
00,000 (by chromatography using polyethylene glycol t-1 quasi-substance). This is referred to as fully sulfonated melamine resin a-(1).

Reference Example 2 (Same) Into the same reaction vessel as in Reference Example 1, add 49.0 g of water while stirring.
parts, melamine 42.0 parts (amine group 1.0 gram equivalent)
, 37 formalin 81.0 parts (1.0 gram equivalent),
Add 26.0 parts of sodium bisulfite (0.25 gram equivalent) and further add 2.2 parts of caustic soda to make 13.1 parts of gold.
Then, the temperature inside the reaction system was raised to 750°C and maintained at the same temperature for 2.5 hours. After that, in the reaction system @ 55 degrees
7.1 parts of concentrated sulfuric acid diluted with 100.0 parts of water was added dropwise over 1 hour to obtain -4.4. When kept at the same temperature for an additional 1.5 hours, the reaction mixture became viscous (2
25.000 cps at 5℃), at this point water 150.0
1 part and kept at the same temperature for another 4 hours to make sure. Thereafter, 5.0 parts of caustic soda and 70.0 parts of water were added, and the mixture was cooled to room temperature. The obtained resin is a colorless translucent liquid with a solid content of 19.
9%, viscosity 370 cps (25°C), ) (110,
The weight average molecular weight was 450.000 (approximately the measurement limit of an e-el-miniature chromatograph).

This will be referred to as gold sulfonated melamine resin a-(2).

Reference Example 3 (Same) In a reaction vessel similar to Reference Example 1, add 57.5 liters of water while stirring.
parts, melamine 42.0 parts, (amine group 1.0 gram equivalent), 37 thiformin 81.0 parts (], O gram equivalent)
, sodium bisulfite (0.33 gram equivalent) was added, and a few ounces of caustic soda was added to adjust the Pl (total 12.0).Then, the temperature in the reaction system was raised to a total of 75°C, and at the same temperature 1. Holds time.

Next, the temperature in the reaction system was brought to 55° C. and 7.5 parts of concentrated sulfuric acid diluted with 100.0 parts of water was added to bring the temperature to -3.9.

Further, it was kept at the same temperature for 12 hours, and then 5,3 liters of caustic soda was added.
M and 61.5 parts of water were added, and the mixture was cooled to room temperature. The obtained resin was a colorless transparent liquid with a solid content of 30.0 cm and a viscosity of (2
5° C.) 550 cps, pH 11.8, and weight average molecular weight 12.0.000.

This is referred to as sulfonated melamine tree III & -(3).

Reference Example 4 (Same) In a reaction vessel similar to Reference Example 1, the same amounts of water, melamine, 37 thiformin, and sodium bisulfite as in Reference Example 3 were charged with stirring, and further 2.2 g of caustic soda was charged.
Pi (total 12.0. After that, the temperature in the reaction system was set to 7.
The temperature was raised to 5°C and maintained at the same temperature for 1 hour.

Then, the total temperature in the reaction system was brought to 55 DEG C., and 6.9 parts of sulfuric acid was diluted with 100.0 parts of water to bring the temperature to -4.5.

The temperature was further maintained for 2 hours, and then 5.0 parts of caustic soda and 59.5 parts of water were added, and the mixture was cooled to room temperature. The resulting resin is a colorless transparent liquid with a solid content of 30.1% and a viscosity of 60.
cps (25°C) Pill, 5, weight average molecular weight 25,000. This is referred to as sulfonated melamine resin a-(4).

Sulfonated melamine resin a with the molecular weight of the plants obtained above
-(1), a-(2), a-(3), and a-(4), and "7 Gin Coat 550", a commercially available emulsion polymer for cement mixing [solid content: 40 chips]. , acrylic type, glass transition temperature (hereinafter abbreviated as rTgJ) 5 parts 5°C; manufactured by Dainippon Ink & Chemicals Co., Ltd.], "Yodozol GF
-5J (Solid content: 45 inches, acrylic steel, Tg
O±5℃; Kanebo NS Co., Ltd.! ! ! ri, and [
Rough Star 0182AJ (solid content 48 cm, SBR type,
Tg-5, 5°C, Dainippon Ink & Chemicals Co., Ltd.) were mixed together, and added to water to adjust the solid content to 20-40%. Table 1 shows a list of formulations.

/ 6 ~ Examples 1 to 8, Comparative Examples 1 to 9 Various physical properties of each admixture listed in Table 1 when kneaded in total cement are summarized in Table 2.

In addition, the test method is the following 9.

〔Test method〕

(1 mix: water/cement ratio is mortar flow 175
Adjust so that it is ±5.

(2) Curing: Air dry curing at 20℃ and 60% moisture.

(3) Strength measurement: 3 specimens with 0 bending strength and compressive strength of 4X4X16cIrL each? 'l:
Measured according to JIS-R-5201 after curing.

0 Layer strength: Apply mortar to the following base material with a trowel.
After curing, install 4 x 4 t, *attachmeno) f,
Determined by Kenken-type adhesive force tester (average of 5 locations) (Base material) Cement concrete 30 x 30 c IIL concrete sidewalk board steel plate: 30 x 30 c IIL polished mild steel plate (CC-150)
Sunday puffer with sandpaper) Ceramic tile: JI
The surface of a product that complies with S-A-5209 (4 No. Mortar pot life (pot life): mortar adjusted to have a flow of 175 ± 5 as above, total temperature 20℃,
Leave it in a 60% RH atmosphere and measure the time it can be worked with a trowel (flow of 150 or more) from the time of blending.

(Evaluation +111i) ◎... 2 hours or more ○... 1 to 2 hours △... 30 to 1 hour The cement composition of the present invention, which contains all admixtures containing a specific proportion of sulfonated melamine m-fat, has excellent bending and compressive strength, and also has excellent adhesion to substrates, and the pot life of the cement composition is extremely long. The fluidity of cement is also good.

Claims (1)

[Claims] 1. Polymer aqueous dispersion (a) obtained by emulsion polymerization of α,β-ethylenically unsaturated monomer and having a glass transition temperature of 30°C or lower, and melamine having a weight average molecular weight of 100,000 or more. The formaldehyde condensate of sulfonate (b) and (a):(b)=20:80 to 99:1
A cement composition made by blending an admixture with cement within the range of (weight/solid content ratio).