JPH09110492A - Admixture for cement extruded product and composition for cement extruded product containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the extrusion pressure and to improve formability, fluidity, surface smoothness, bending strength, etc., by using a single polymer or copolymer of a specified compd. as the main component of the admixture. SOLUTION: This admixture for a cement extruded product is obtd. by (co) polymn. of 20-100wt.% compd. expressed by formula I (R<1> and R<2> are each H or methyl groups), 0-80wt.% of a compd. expressed by formula II (R<3> is H or a methyl group, R<4> is 1-4C straight-chain or branched-chain alkylene group, X<1> is H, alkali metals, ammonium salt or org. ammonium salt), and 0-40wt.% of a compd. expressed by formula III in the presence of a radical polymn. initiator. In formula III, R<5> is H or a methyl group, X<2> is CN, COOR<6> , CONH2 , CONHR<7> , COR<8> , OCOR<9> , OR<10> , R<6> is an alkali metal, ammonium salt, or 1-4C alkyl group (wherein H in the alkyl group can be replaced by OH or 1-4C di-substd. alkylamino group), and R<7> -R<10> are 1-4C alkyl groups. When the admixture is dissolved in a supernatant of a cement, the soln. has 100 to 10,000cps viscosity (with 1.2wt.% measured by a B-type rotary viscometer).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an admixture to be added to a composition for cement extruded products, and more specifically to a composition for cement extruded products which has excellent moldability, fluidity, surface smoothness, and reduced extrusion pressure. And further relates to an admixture for improving bending strength and the like. The present invention also relates to a composition for cement extruded products to which the admixture is added.

[0002]

2. Description of the Related Art When extruding a water-kneaded product containing cementitious material as a main component, a particular problem is that the water-kneaded product has a poor water-retaining property due to the extrusion pressure applied to the die, which causes a dehydration phenomenon and makes extrusion impossible. Is to be. Conventionally, in order to prevent this dehydration phenomenon, cellulose derivatives such as methyl cellulose ether, hydroxypropyl methyl cellulose ether, methyl hydroxyethyl methyl cellulose ether, hydroxyethyl cellulose ether, hydroxypropyl cellulose ether, and partial hydrolysis of polyvinyl alcohol, polyethylene oxide, polyacrylamide, etc. It is known from JP-B-43-7134 to add a water-soluble polymer substance such as a decomposition product.

However, in such a conventional cement extrusion molded plate, demands for performance such as heat resistance, sound insulation and durability have been improved in recent years, and molded products having complicated shapes are increasing. A very high decoupling force acts during extrusion molding of such a complicated shape, and the frictional heat generated inside thereof causes the temperature of the cement kneaded product to rise, particularly in summer, to 40 to 90 ° C. In the cement extrusion molding at such a high temperature, among the admixtures for cement extrusion molding plates, the admixtures such as methylcellulose, hydroxypropylmethylcellulose and hydroxyethylmethylcellulose having a gel point are 40 to 90.
Since it causes gelation at high temperature of ℃, the function as an admixture for extruded plates decreases significantly, the water retention function of cement-kneaded products is lost, the extrusion pressure rises rapidly, and the extruded plates crack. There was a problem.

JP-A-60-104109 reports that an N-vinylacetamide compound is used as a copolymerization component as a dispersant for cement slurry, but the content of the N-vinylacetamide compound is 0 to 0. It is as small as 5% by weight, and its effect has not been clarified for the use of cement extruded boards as the use of the present invention. Further, JP-A-60-42403 discloses a cross-linked product of a copolymer containing an N-vinylacetamide compound, but this is not for improving the fluidity of cement and is not suitable for the construction. The invention was invented with the intention of absorbing excess water in the crosslinked product. In addition, Japanese Patent Publication 2-235
Japanese Patent Publication No. 66 discloses a copolymer of an N-vinylacetamide compound and 2-acrylamido-2-methylpropanesulfonate, the use of which is a water-soluble boring aid. The copolymer of the present invention has a dispersion-stabilizing effect on the inorganic particles as well as the effect of the present invention, and also stabilizes the dispersion of the cement particles by the surface-active effect. This is to reduce the extrusion pressure by imparting fluidity to the product.

[0005]

In view of the above circumstances, the present invention provides a cement extrusion molded article composition which has a good moldability when the cement extrusion molded article is molded without causing deterioration of the dehydration function due to high temperature gelation. An object of the present invention is to provide an admixture for a cement extrusion molded article, which brings about fluidity, surface smoothness, lowering of extrusion pressure, and further improves bending strength and the like.

[0006]

In view of such circumstances,
As a result of repeated intensive studies, the admixture for a cement extrusion molded product of the present invention brings a composition for a cement extrusion molded product into moldability, fluidity, surface smoothness, decrease in extrusion pressure, and further flexural strength and the like. Found to improve. That is, the present invention is characterized by being a water-soluble polymer which is a specific (co) polymer. Addition of water-soluble polymer does not cause deterioration of dehydration function due to high-temperature gelation during molding of cement extrusion molded plate, and it has moldability and fluidity in composition for cement extrusion molded product or hydraulic compound. Is an admixture for cement extruded products, which has improved properties, surface smoothness, extrusion pressure, and improved bending strength.

The present invention provides (A) general formula (1) CH ₂ ═C
HNR ¹ COR ² (wherein, R ¹ and R ² independently represent a hydrogen atom or a methyl group), a homopolymer of the compound, or a copolymer of the compound with a monomer copolymerizable with the compound. Regarding an admixture for a cement extrusion molded article, which is characterized by comprising:

(B) General formula (1) CH ₂ ═CHNR ¹ C
20 to 100% by weight of a compound represented by OR ² (wherein, R ¹ and R ² independently represent a hydrogen atom or a methyl group), and general formula (2) CH ₂ ═CR ³ CONHR ⁴ SO ₃
X ¹ (In the formula, R ³ represents a hydrogen atom or a methyl group, R ⁴ represents a linear or branched alkylene group having 1 to ⁴ carbon atoms, X ¹ represents a hydrogen atom, an alkali metal, an ammonium salt or an organic ammonium salt. 0 to 80% by weight of the compound represented by the formula (3) CH ₂ ═CR ⁵ X ² (wherein R ⁵ is a hydrogen atom or a methyl group, X ² is CN, COOR ⁶ , CO).
NH _2, CONHR ⁷ , COR ⁸ , OCOR ⁹ or OR
Indicates ^10, R ⁶ is a hydrogen atom, an alkali metal, an ammonium salt, a hydrogen atom of an alkyl group (the alkyl group of the organic ammonium salt or 1 to 4 carbon atoms is OH, di-substituted alkyl amino group having 1 to 3 carbon atoms Can be replaced.)
R ^{7 to} R ¹⁰ independently represent an alkyl group having 1 to 4 carbon atoms. ) A compound for a cement extrusion molded article, which comprises a (co) polymer having 0 to 40% by weight of the compound represented by the formula (1) as a monomer,

(C) An aqueous solution of a homopolymer or a copolymer dissolved in a cement supernatant liquid has a 1.2 wt% aqueous solution viscosity of 100 to 10,000 cps in a B type rotational viscometer.
And (D) cement, sand and the admixture for cement extruded products according to any one of claims 1 to 3, which is characterized in that It relates to a composition for extruded products.

As the compound represented by the general formula (1),
N-vinylformamide, N-vinylacetamide, N
-Methyl-N-vinylformamide, N-methyl-N-
Vinylacetamide may be mentioned, but N is particularly preferable.
-Vinylacetamide.

As the compound represented by the general formula (2),
For example, 2-acrylamido-2-methyl-propanesulfonic acid, 2-acrylamidoethanesulfonic acid, 2-methacrylamidoethanesulfonic acid, 3-methacrylamidopropanesulfonic acid or salts thereof can be mentioned as suitable examples.

As the compound represented by the general formula (3),
For example, methyl acrylate, ethyl acrylate, propyl acrylate, 2-hydroxyethyl acrylate, acrylamide, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl acrylamide, acrytonitrile, methyl vinyl ketone, ethyl vinyl ketone, propyl Vinyl ketone, vinyl acetate, methyl vinyl ether, ethyl vinyl ether,
Propyl vinyl ether, methyl methacrylate, ethyl methacrylate, propyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, N, N-dimethylaminoethyl methacrylate, methacrylamide, N, N-dimethylaminopropyl methacrylamide, N, N- Examples thereof include dimethylacrylamide and N, N-diethylacrylamide.

When the amount of the compound represented by the general formula (1) is less than 20% by weight, it becomes difficult to impart sufficient water retention property to the cement paste. When the compound represented by the general formula (2) is 80% by weight, the smoothness of the surface of the molded plate tends to deteriorate. The compound represented by the general formula (3) is 4
If it exceeds 0% by weight, it becomes difficult to obtain a water-soluble copolymer, so that water retention and fluidity cannot be imparted to the cement paste. The viscosity of a 1.2% aqueous solution at 20 ° C is 10
If it is less than 0 cps, sufficient water retention cannot be imparted to the cement paste. On the other hand, when it exceeds 10,000 cps, the fluidity is lowered, the extrusion pressure is increased, and the number of cracks for extrusion molded products is increased. The 1.2% aqueous solution viscosity referred to here means that the copolymer is brought to a concentration of 1.2% by weight by using 3 L of water added to 30 g of Portland cement, stirring for 30 minutes, and then leaving still. It is a value obtained by measuring the viscosity of the adjusted liquid with a Brookfield rotational viscometer at 60 rpm.

In order to produce the cement admixture according to the present invention, methods such as aqueous solution polymerization, reverse phase suspension polymerization and precipitation precipitation polymerization can be used, but are not particularly limited to these methods. As the polymerization initiator, an ordinary radical polymerization initiator can be used, and 2,2′-azobis (2
-Amidinopropane) dihydrochloride, 2,2-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride, 2,2'-azobis [2-
(3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (5-hydroxy-3,4,5,6-tetrahydropyrimidin-2-ylpropane] dihydrochloride, Azo initiators such as 2,2′-azobis [2- (N-benzylamidinopropane] dihydrochloride, t-
Butyl hydroperoxide, peroxides such as succinic acid peroxide, or so-called redox initiators, etc., in which peroxides or persulfates and reducing agents such as triethanolamine and sodium thiosulfate are present in the same system, can give. The copolymer obtained by the aqueous solution polymerization can be dried and pulverized into powder. The copolymer obtained by the reverse phase suspension polymerization can be filtered and dried to obtain a powder. The resulting powder is added as a powder to the extrudate formulation. In addition, some of the aqueous solutions having low viscosity are hard to be made into powders, so that the aqueous solutions can be used as they are. In this case, n-butyl mercaptan having a chain transfer action, triethylamine, isopropyl alcohol, thioglycol-
Ammonium acetate, sodium hypophosphite, etc. are used.

Examples of the composition for cement extruded products containing cement and sand as essential components include, for example, 100 parts by weight of Portland cement, 25 parts by weight of silica sand, and fibrous reinforcing agent 3.
1 part by weight and 1.3 parts by weight of an admixture are added to form a premix agent, and water is added to form a paste.

The additive amount of the admixture is 0.1 to 3.0% by weight based on the composition for cement extrusion molding,
Preferably it is 0.5 to 2.0% by weight. 0.1% by weight
If the amount is less, sufficient water retention cannot be given to the cement paste. When it is more than 3.0% by weight, the fluidity is remarkably reduced, which is not preferable. If necessary, a water-soluble polymer that can be added as a cement extrusion molded product admixture can be used in combination with the cement extrusion molded product admixture of the present invention. Examples of such water-soluble polymers include, but are not limited to, methyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, hydroxyethyl cellulose and the like.

The present invention will be specifically described below with reference to production examples and examples, but the present invention is not limited thereto.

[0018]

【Example】

Production Example 1 250 g of N-vinylacetamide was placed in a glass reactor, and 740 g of water was added and dissolved. After removing dissolved oxygen by nitrogen aeration in a thermostat at 20 ° C., 0.125 g of 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride dissolved in 10 g of water was added. In addition, the reaction was performed under aeration of nitrogen. After the completion of the reaction, the product was dried at 50 ° C. for 5 hours. After sufficient removal of water, the powder was reduced to 100 mesh or less by a small crusher. The obtained copolymer has a 1.2% aqueous solution viscosity of 3
00 cps.

Production Example 2 In a glass reactor, 2-acrylamido-2-methyl-
100 g of propanesulfonic acid was added, and 365 g of water was added and dissolved. The pH was adjusted to 8 with sodium hydroxide, and 25 g of N-vinylacetamide was dissolved.
The mixture was vigorously stirred in a constant temperature bath at ℃. After removing dissolved oxygen by nitrogen aeration, dissolved in 10 g of water 2,
2'-azobis [2- (2-imidazolin-2-yl)
Propane] dihydrochloride (0.2 g) was added, and the mixture was reacted under nitrogen aeration. After the reaction was completed, the product was dried at 105 ° C for 5 hours. After sufficient removal of water, the powder was reduced to 100 mesh or less by a small crusher. The obtained copolymer had a 1.2% aqueous solution viscosity of 650 cps.

Production Example 3 In a glass reactor, 2-acrylamido-2-methyl-
25 g of propanesulfonic acid was added, and 445 g of water was added and dissolved. The pH was adjusted to 8 with sodium hydroxide, and 25 g of N-vinylacetamide and 0.01 g of sodium hypophosphite were dissolved. In a constant temperature bath at 50 ° C, vigorously stir and remove dissolved oxygen by aeration with nitrogen, add 0.5 g of 2,2'-azobis (2-amidinopropane) dihydrochloride dissolved in 5 g of water, and aerate with nitrogen. Reacted below. The copolymer obtained is 1.2%
The aqueous solution had a viscosity of 384 cps.

Production Example 4 A glass reactor was charged with N-vinylacetamide 112.5.
g, 12.5 g of acrylonitrile, and 0.0625 g of sodium hypophosphite were added, and 360 g of water was added and dissolved. In a 20 ° C. constant temperature bath, dissolved oxygen was removed by aeration of nitrogen, and then dissolved in 10 g of water, 2,2′-azobis [2- (2-imidazolin-2-yl) propane]
0.2 g of dihydrochloride was added, and the reaction was carried out under aeration of nitrogen. After the completion of the reaction, the product was dried at 50 ° C. for 5 hours. After sufficient removal of water, the powder was reduced to 100 mesh or less by a small crusher. The copolymer obtained is 1.2
% Aqueous solution viscosity was 95 cps.

Production Example 5 In a glass reactor, 2-acrylamido-2-methyl-
35 g of propanesulfonic acid was added, and 445 g of water was added and dissolved. The pH was adjusted to 8 with sodium hydroxide, and 10 g of N-vinylacetamide, 5 g of acrylonitrile and 0.01 g of sodium hypophosphite were dissolved. In a constant temperature bath at 50 ° C, vigorously stir and remove dissolved oxygen by aeration with nitrogen, add 0.5 g of 2,2'-azobis (2-amidinopropane) dihydrochloride dissolved in 5 g of water, and aerate with nitrogen. Reacted below.
The obtained copolymer has a 1.2% aqueous solution viscosity of 290 cps.
Met.

Examples 1 to 7 The copolymers obtained in Production Examples 1 to 5 were added to the composition for extrusion molded plate, and the effect was examined. Here cement: sand =
4: 1, W / C = 0.28. Table 1 shows the results
And 2.

[0024]

[Table 1]

[0025]

[Table 2]

Examples 8 to 14 The copolymers obtained in Production Examples 1 to 5 were added to compositions for fireproof double pipes, and their effects were investigated. Here cement: sand =
4: 3, W / C = 0.6. The results are shown in Tables 3 and 4.

[0027]

[Table 3]

[0028]

[Table 4]

[0029]

The addition of the admixture for cement extrusion molded articles of the present invention brings about excellent moldability, fluidity, surface smoothness, and reduction of extrusion pressure in the composition for cement extrusion molded articles. Material mechanical properties are improved.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08F 218/04 MLH C08F 218/04 MLH 220/06 MLS 7824-4J 220/06 MLS MLU 7824-4J MLU 220/12 MME 220/12 MME 220/28 MMN 220/28 MMN 220/34 MMR 220/34 MMR 220/42 MMY 220/42 MMY 220/58 MNG 220/58 MNG // (C04B 28/02 24: 26 14:06 14:38) 103: 32 103: 44

Claims (4)

[Claims] 1. General formula (1) CH ₂ ═CHNR ¹ COR
² (in the formula, R ¹ and R ^{2 each} independently represent a hydrogen atom or a methyl group), or a homopolymer of the compound or a copolymer of the compound and a monomer copolymerizable with the compound. An admixture for cement extrusion products characterized by: 2. General formula (1) CH ₂ ═CHNR ¹ COR
² (wherein R ¹ and R ² independently represent a hydrogen atom or a methyl group) 20 to 100% by weight, the general formula (2) CH ₂ ═CR ³ CONHR ⁴ SO ₃ X
¹ (In the formula, R ³ represents a hydrogen atom or a methyl group, R ⁴ represents a linear or branched alkylene group having 1 to ⁴ carbon atoms, and X ¹ represents a hydrogen atom, an alkali metal, an ammonium salt or an organic ammonium salt. 0 to 80% by weight of a compound represented by the formula: CH ₂ ═CR ⁵ X ² (wherein R ⁵ is a hydrogen atom or a methyl group, X ² is CN, COOR ⁶ , CO
NH _2, CONHR ⁷ , COR ⁸ , OCOR ⁹ or OR
Indicates ^10, R ⁶ is a hydrogen atom, an alkali metal, an ammonium salt, a hydrogen atom of an alkyl group (the alkyl group of the organic ammonium salt or 1 to 4 carbon atoms is OH, di-substituted alkyl amino group having 1 to 3 carbon atoms Can be replaced.)
R ^{7 to} R ¹⁰ independently represent an alkyl group having 1 to 4 carbon atoms. An admixture for a cement extrusion molded article, which comprises a (co) polymer having 0 to 40% by weight of the compound represented by the formula (1) as a monomer. 3. A B-type rotational viscometer of an aqueous solution obtained by dissolving a homopolymer or a copolymer in a cement supernatant.
The admixture for a cement extrusion molded article according to claim 1, wherein the viscosity of a 2% by weight aqueous solution is 100 to 10,000 cps. 4. A composition for a cement extruded product, which comprises cement, sand and the admixture for a cement extruded product according to any one of claims 1 to 3.