JP2000026146A - Powdery cement dispersant and cement composition using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a powdery cement dispersant with high concn. easy to handle by adding a polyalkylene glycol or a fatty acid having a specified number of C atoms to an aq. soln. of a polycarboxylic acid type high molecular compd. having a polyalkylene glycol chain and converting the aq. soln. into dry powder. SOLUTION: The powdery cement dispersant contains particles contg. 100 pts.wt. polycarboxylic acid type high molecular compd. having a polyalkylene glycol chain, about 0.2-30 pts.wt. polyalkylene glycol or 8-22C fatty acid and, optionally, about 0.1-30 pts.wt. inorg. powder and preferably has 5-2,000 μm average particle diameter. The polycarboxylic acid type high molecular compd. is preferably a (meth)acrylic acid or maleic acid copolymer having a number average mol.wt. of about 2,000-50,000. The polyalkylene glycol is preferably a polyethylene glycol having a number average mol.wt. of 1,000-200,000 or a polypropylene glycol having a number average mol.wt. 2,000-6,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cement dispersant used for producing a cement composition having excellent fluidity, and more particularly, to a cement dispersion of powder which can be preliminarily incorporated into a premix product. Agent.

[0002]

2. Description of the Related Art In general, it is desirable that a composition using cement, such as concrete or mortar, has a small water-cement ratio (W / C ratio) in order to improve strength and durability. However, when the W / C ratio is small, there is a problem that the fluidity and workability deteriorate. Therefore, even if the W / C ratio is small, good fluidity and workability can be secured.
Cement dispersants have been used.

[0003] In recent years, examples of using a dispersant containing a polycarboxylic acid-based polymer as a main component as a cement dispersant capable of obtaining good fluidity at a low water cement ratio have been increasing.

[0004]

However, since a dispersant containing a polycarboxylic acid-based polymer as a main component is generally produced as an aqueous solution, it is not possible to mix it in a premix product such as plastering material in advance. However, there is a drawback that the cost is higher than that of the powder cement dispersant in transportation and the like.

[0005] In addition, powder cement dispersants which are currently widely used and are mainly composed of a naphthalene sulfonate formalin condensate and a melamine sulfonate formalin condensate are carcinogenic according to the evaluation of IARC (International Agency for Research on Cancer). Therefore, a powder cement dispersant containing a polycarboxylic acid-based polymer compound as a main component is desired from the viewpoint of safety because it may contain formalin.

As a technique for pulverizing a cement admixture such as a liquid cement dispersant, a method utilizing the heat of digestion reaction of quick lime (Japanese Patent Publication No. 7-14829) and a method using a spray dryer (Japanese Patent No. 2669761). ), A method of reducing the solubility of a polymer compound, which is a main component of a cement dispersant, in water to facilitate powderization (JP-A-9-3097)
No. 56), but when these methods are used to produce a powder cement dispersant having a high polycarboxylic acid-based polymer compound concentration, it becomes a gum in the process of drying and solidifying, or the powdered one is solidified. And a large amount of heat energy is required for drying, and the performance of the dispersant for cement is deteriorated. Accordingly, an object of the present invention is to solve the above problems and to provide a powder cement dispersant obtained by pulverizing an aqueous solution of a polycarboxylic acid polymer compound used in a cement dispersant at a high concentration.

[0007]

Means for Solving the Problems In view of such circumstances, the present inventors have conducted intensive research to solve the above problems, and as a result,
The content of the polycarboxylic acid-based polymer compound is reduced by drying and powdering the polycarboxylic acid-based polymer compound having a polyalkylene glycol chain together with one or more substances selected from polyalkylene glycols and fatty acids. It has been found that even when the temperature is increased, the state becomes gum-like and cannot be powdered, and that the powdered substance does not solidify and a powder cement dispersant in a good state can be obtained, and the present invention has been completed.

That is, the present invention relates to a polycarboxylic acid polymer having a polyalkylene glycol chain, one or more selected from polyalkylene glycols and fatty acids having 8 to 22 carbon atoms, and an inorganic powder if necessary. It is intended to provide a powdery cement dispersant containing particles containing, and a cement composition containing the same and cement.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The polycarboxylic acid polymer having a polyalkylene glycol chain used in the present invention is:
There is no particular limitation as long as it is used as a cement dispersant. Examples thereof include (a) a (meth) acrylic acid-based copolymer and (b) a maleic acid-based copolymer. The above may be used as a mixture.

Among these, (a) includes a group —COO
M (wherein, M represents a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium or an organic amine) and a (meth) acrylic acid-based copolymer having a polyalkylene glycol chain are preferred. b)
Preferred examples include a polyalkylene glycol alkenyl ether-maleic anhydride copolymer described in JP-A-6-239652.

M in the group (COOM) of the (meth) acrylic acid-based copolymer (a) is a hydrogen atom; an alkali metal such as sodium or potassium; an alkaline earth metal such as calcium or magnesium; ammonium or an organic compound. Amines are preferred. Further, the polyalkylene glycol chain is represented by -O (C
H ₂ C (R ^a ) HO) _b —, wherein R ^a represents a hydrogen atom or a methyl group, b is preferably from 5 to 109, particularly preferably from 20 to 109, further preferably from 30 to 109 .

Further, preferred as (a) are:
In all the structural units, 40 to 80 mol% of the structural unit (1) represented by the following formula (1), 2 to 25 mol% of the structural unit (2) represented by the following formula (2), and the following formula (3) (Meth) acrylic acid having a number average molecular weight of 2000 to 50,000 having 3 to 20 mol% of the structural unit (3) represented by formula (1) and 1 to 45 mol% of the structural unit (4) represented by the following formula (4). Acid-based copolymers are exemplified.

[0013]

Embedded image

[Wherein R¹, R^Two, R^FourAnd R^FiveAre the same
Or differently represents a hydrogen atom or a methyl group;^ThreeAnd R
⁶Represents an alkyl group having 1 to 3 carbon atoms;¹Is hydrogen field
Metal, alkali metal, alkaline earth metal, ammonium or
Represents an organic amine, and X represents -SO _ThreeM^TwoOr -O-Ph-
SO_ThreeM^Two(Where M^TwoIs a hydrogen atom, an alkali metal,
Indicating alkaline earth metal, ammonium or organic amine,
Ph represents a phenylene group), and n represents 5 to 109
Indicates an integer)

In the above formulas (1) to (4), R ¹ , R ² , R
⁴ and R ⁵ are preferably a methyl group. R ³ and R ⁶
As a methyl group, an ethyl group, an n-propyl group, an i-
A propyl group is exemplified, and a methyl group is particularly preferred. Further, as M ¹ , sodium, potassium, calcium, magnesium, alkanolamine and the like are preferable,
Particularly, sodium is preferable from the viewpoint of solubility in water. Examples of M ² in the group X include alkali metal atoms such as sodium and potassium, alkaline earth metals such as calcium and magnesium, and organic amines such as alkanolamines such as ammonium and ethanolamine.
As Among these X, -SO ₃ Na are preferred. Further, n in the formula (4) is preferably from 5 to 109, particularly preferably 20 to
To 109, more preferably 30 to 109. The content of the structural unit (1) is preferably from 40 to 80 mol%, and particularly preferably from 45 to 75 mol%. The content of the structural unit (2) is preferably 2 to 25 mol%, and particularly preferably 5 to 25 mol%.
Preferably, it is 20 mol%. The content of the structural unit (3) is preferably from 3 to 20 mol%, particularly preferably from 5 to 15 mol%. The structural unit (4) is 1
It is preferable that it is -45 mol%, and it is especially preferable that it is 3-40 mol%. In addition, mol% of a structural unit is
The molar% of each structural unit is shown when all the structural units of (1) to (4) are 100 mol%.

Particularly preferred as (a) is a constitutional unit represented by the following formula (5) in an amount of 40 to 70 mol% in all the constitutional units, 5 to 30 mol% of (6), 1 to 20 mol% of the structural unit (7) represented by the following formula (7), 1 to 30 mol% of the structural unit (8) represented by the following formula (8), A (meth) acrylic acid-based copolymer having a number average molecular weight of 2,000 to 50,000 and a structural unit (9) represented by the following formula (9) at a ratio of 1 to 30 mol% is exemplified.

[0017]

Embedded image

[Wherein, R⁷, R⁸, R^Ten, R¹¹, R¹³Passing
And R¹⁴Represent the same or different hydrogen atoms or methyl groups
Then R⁹, R¹²And R^FifteenRepresents an alkyl group having 1 to 3 carbon atoms.
Show, M ^ThreeIs hydrogen atom, alkali metal, alkaline earth gold
Genus, ammonium or an organic amine, where Y is -SO_Three
M^FourOr -O-Ph-SO_ThreeM^Four(Where M^FourIs hydrogen field
Metal, alkali metal, alkaline earth metal, ammonium or
Represents an organic amine, and Ph represents a phenylene group).
And m represents an integer of 5 to 109, and p is an integer of 5 to 50.
Is shown.

In the above formulas (5) to (9), R ⁷ , R ⁸ , R
¹⁰ , R ¹¹ , R ¹³ and R ¹⁴ are preferably a methyl group. Also,
R ⁹ , R ¹² and R ¹⁵ are a methyl group, an ethyl group, n
-Propyl group and i-propyl group. Among them, a methyl group is preferable. As M ³ and M ⁴ , sodium, potassium, calcium, magnesium, alkanolamine and the like are preferable, and sodium is particularly preferable.
The -SO ₃ Na is preferably a group Y. In the formula (8), m is preferably from 5 to 109, particularly preferably from 20 to 109, and more preferably from 30 to 109. Further, p in the formula (9) is preferably from 5 to 109, particularly preferably from 20 to 109, and more preferably from 30 to 109. The content of the structural unit (5) is preferably from 40 to 70 mol%, particularly preferably from 45 to 6 mol%.
Preferably it is 5 mol%. The structural unit (6) is 5
Preferably it is 30 mol%, especially 8 to 23 mol%
It is preferred that The content of the structural unit (7) is preferably 1 to 20 mol%, particularly preferably 1 to 15 mol%. The content of the structural unit (8) is preferably from 1 to 30 mol%, particularly preferably from 5 to 25 mol%. Further, the content of the structural unit (9) is preferably 1 to 30 mol%, and particularly preferably 3 to 25 mol%. In addition, mol% of a structural unit shows mol% of each structural unit when the total of all the structural units of (5)-(9) is 100 mol%.

The (meth) acrylic acid-based copolymer comprising the above structural units includes a number average molecular weight of 2,000 to 5,000.
0 (GPC method, polyethylene glycol equivalent) is preferable, and 3500 to 30,000 is more preferable.

On the other hand, as the polyalkylene glycol used for powdering, polyethylene glycol having a molecular weight of 1,000 to 20,000 and polypropylene glycol having a molecular weight of 2,000 to 6,000 are preferred.
Of these, polyethylene glycol is particularly preferred, and polyethylene glycol having an average molecular weight of 2,000 to 4,000 is more preferred.

The fatty acid having 8 to 22 carbon atoms may be saturated or unsaturated, and may be linear or branched. Specifically, caprylic acid, pelargonic acid,
Capric acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachinic acid, behenic acid, undecylenic acid, oleic acid, elaidic acid, setleyic acid, erucic acid , Brassic acid and salts thereof. As the salts of the above fatty acids, metal salts such as sodium, potassium, barium, calcium, zinc, aluminum and magnesium are preferable. Of these, stearic acid and salts thereof are preferred, and particularly preferred is calcium stearate.

The polyalkylene glycol and the fatty acid are
One type or two or more types may be used as a mixture, and the amount used is 0.2 to 30 parts by weight with respect to 100 parts by weight of the solid content of the polymer compound such as the polycarboxylic acid-based polymer compound. It is particularly preferable to use 0.5 to 20 parts by weight.

In the present invention, an inorganic powder may be further added in addition to the above essential components. As the inorganic powder used in the present invention, a powder of an inorganic salt such as calcium carbonate or calcium silicate, a clay mineral powder such as kaolinite or bentonite, or a fine powder such as blast furnace slag or fly ash can be used. These inorganic powders are particularly effective for pulverizing polymer compounds which are difficult to pulverize, but in order to pulverize the aqueous solution of the polymer compound at a high concentration, the amount of the inorganic powder used is high. The amount is preferably 0.1 to 30 parts by weight, particularly preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the solid content of the molecular compound aqueous solution.

The cement admixture of the present invention has an average particle size of 5 to 5.
It is preferably in the range of 2000 μm, particularly 10 to
Preferably it is 1000 μm. Average particle size is 5μm
If it becomes less, the powder cement dispersant tends to aggregate,
If it exceeds 2,000 μm, the solubility in water decreases, and the dispersibility in cement over time increases, which is not preferable. The powdery cement dispersant of the present invention comprises, for example, a polycarboxylic acid-based polymer compound, one or more selected from polyalkylene glycols and fatty acids having 8 to 22 carbon atoms, an inorganic powder if necessary, and water. Can be produced by drying and solidifying a mixture containing Preferably, when the powder is dried while kneading and stirring, it is relatively easily crushed, so that a powder cement dispersant having a high content of a polycarboxylic acid-based polymer compound and a good condition can be produced. Dry powdering by kneading and stirring is preferably performed in a reduced pressure state or a dry gas atmosphere while heating to about 40 to 120 ° C., preferably 60 to 100 ° C., so that the polycarboxylic acid-based polymer compound is A powder in a good state can be obtained without deterioration. The dried and powdered cement dispersant has an average particle size of 5 to 2,000 by any pulverizing / classifying method.
It is desirable to adjust the thickness to μm, preferably 10 to 1000 μm.

The cement to which the cement dispersant of the present invention can be applied is not particularly limited, and is usually a mixed cement such as ordinary Portland cement, blast furnace cement, silica cement, fly ash cement, etc. Alkali cement may be used, and it is also effective for spraying cement containing a quick-hardening material. Further, it is also effective for a concrete composition in which blast furnace slag and fly ash are added at the time of concrete preparation.

The amount of the powder cement dispersant of the present invention added to cement is 0.01 to 100 parts by weight of cement.
It is preferably 5 parts by weight, particularly preferably 0.05 to 3 parts by weight. Further, the cement composition of the present invention can contain various commonly used aggregates, extenders, admixtures and the like as long as the effects of the present invention are not impaired.

[0028]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.
The materials used in the examples are as follows.

[Materials used]

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

Polyalkylene glycol: polyethylene glycol (molecular weight: 4,000), fatty acid: calcium stearate, manufactured by Kanto Chemical Co., Ltd. Inorganic powder: calcium carbonate, manufactured by Kanto Chemical Co., Ltd. Cement: ordinary Portland cement manufactured by Chichibu Onoda Co., Ltd. Cement dispersant used in the above: Naphthalene sulfonate formalin condensate (Mighty 1 manufactured by Kao Corporation)
00) Melamine sulfonate formalin condensate (SKW TR
(Merment F10M manufactured by OSTBERG AG) [Dry powdering method] Drying machine: Rotary evaporator (Model R114-A-W, manufactured by Shibata Scientific Co., Ltd.) [Moisture measurement method] Ket moisture meter (KETT ELE)
FD-60 manufactured by CTRIC LABORATORY
Measured at 0)

Example 1 A rotary evaporator was charged with a mixture of 33 g of an aqueous solution of a polycarboxylic acid polymer compound (30% solid content) and 1 g of polyethylene glycol (molecular weight 4000) shown in Table 1, and the bath temperature was 80 ° C. and the degree of vacuum was 30 Torr. Then, concentrate to dryness (5 hours), crush the solid in a mortar, particle size 50-50
0 μm to obtain a powder cement dispersant (powder dispersant 1) of the present invention.

Example 2 A rotary evaporator was charged with a mixture of 33 g of an aqueous solution of a polycarboxylic acid polymer compound (solid content: 30%) shown in Table 1 and 1 g of calcium stearate. The mixture was dried and powdered under the same conditions as in Example 1; A powder dispersant 2) was obtained.

EXAMPLE 3 A rotary evaporator was charged with a mixture of 33 g of an aqueous solution of a polycarboxylic acid polymer compound (solid content 30%), 1 g of polyethylene glycol (molecular weight 4000) and 1 g of calcium stearate as shown in Table 1. The powder was dried and powdered under the same conditions to obtain (Powder Dispersant 3).

Example 4 A rotary evaporator was charged with a mixture of 33 g of an aqueous solution of a polycarboxylic acid polymer compound (solid content 30%), 1 g of polyethylene glycol (molecular weight 4000) and 1 g of calcium carbonate shown in Table 1. Dry powdering was performed under the same conditions to obtain (powder dispersant 4).

Example 5 A rotary evaporator was charged with a mixture of 33 g of an aqueous solution of a polycarboxylic acid polymer compound (solid content 30%) shown in Table 1 and 1 g of calcium stearate and 1 g of calcium carbonate, and dried under the same conditions as in Example 1. This was powdered to obtain (powder dispersant 5).

Example 6 A rotary evaporator was charged with a mixture of 33 g of an aqueous solution of a polycarboxylic acid polymer compound (solid content 30%) shown in Table 2 and 0.5 g of polyethylene glycol (molecular weight 4000) under the same conditions as in Example 1. And dried to obtain (powder dispersant 6).

Example 7 A rotary evaporator was charged with a mixture of 33 g of a polycarboxylic acid-based polymer compound aqueous solution (solid content 30%) shown in Table 3 and 1 g of polyethylene glycol (molecular weight 4000), and dried under the same conditions as in Example 1. This was powdered to obtain (powder dispersant 7).

Example 8 A rotary evaporator was charged with a mixture of 33 g of a polycarboxylic acid-based polymer compound aqueous solution (solid content 30%) shown in Table 3 and 1 g of calcium stearate, and dried under the same conditions as in Example 1 to obtain a powder. A powder dispersant 8) was obtained.

Example 9 A rotary evaporator was charged with a mixture of 33 g of an aqueous solution of a polycarboxylic acid polymer compound (solid content 30%) shown in Table 3, 1 g of polyethylene glycol (molecular weight 4000) and 1 g of calcium stearate. Dry powdering was performed under the same conditions to obtain (powder dispersant 9).

Example 10 A rotary evaporator was charged with a mixture of 33 g of an aqueous solution of a polycarboxylic acid-based polymer compound (solid content 30%), 1 g of polyethylene glycol (molecular weight 4000), and 1 g of calcium carbonate as shown in Table 3. Dry powdering was performed under the same conditions to obtain (powder dispersant 10).

Example 11 A rotary evaporator was charged with a mixture of 33 g of an aqueous solution of a polycarboxylic acid polymer compound (solid content 30%) shown in Table 4 and 0.5 g of polyethylene glycol (molecular weight 4000) under the same conditions as in Example 1. And dried to obtain (powder dispersant 11).

Comparative Examples 1 to 4 33 g of an aqueous solution of a polycarboxylic acid polymer compound (solid content: 30%) shown in Tables 1 to 4 was dried under the conditions of Example 1 and dispersed in a powder cement shown in Table 5. Agent (powder dispersant 12
To 15).

[0047]

[Table 5]

As shown in Table 5, polyalkylene glycol and / or
In addition, it can be seen that those using no fatty acid (Comparative Examples 1 to 4) cannot efficiently obtain a good powder cement dispersant.

The performance test of the obtained powder cement dispersant was performed as follows.

Test Example 27 parts by weight of water was added to 100 parts by weight of ordinary Portland cement, and the mixture was mixed using a Hobart mixer for 3 minutes to prepare a paste, and the flow value was measured. In addition, the powder cement dispersant of the present invention is used by being mixed in advance with cement (by the percentage of the cement), and the aqueous solution of the polycarboxylic acid polymer compound is used by being mixed with the kneading water (by the percentage of water). did. Table 6 shows the test results. [Flow value measurement method] A vinyl chloride pipe (internal volume: 100 ml) having an inner diameter of 50 mm and a height of 51 mm was placed on a 5 mm-thick shingle glass sheet, and after filling with the adjusted paste,
Pull up the pipe. After the spread had stopped, the diameter in two perpendicular directions was measured, and the average value was taken as the flow value.

[0051]

[Table 6]

Table 6 shows that the product of the present invention has a higher dispersing effect than the existing powder dispersant.

[0053]

The powder cement dispersant of the present invention is obtained by pulverizing an aqueous solution of a cement dispersant containing a polymer having a specific structure as a main component, which has conventionally been difficult to powder, using a specific additive. It can be used for premix products, and exhibits excellent performance with a small amount of addition compared to conventional powder cement dispersants.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08K 5/09 C08K 5/09 C08L 55/00 C08L 55/00 71/02 71/02 // C08F 290/06 C08F 290 / 06 C04B 103: 40 (72) Inventor Hirotaka Isomura 2-4-2 Daisaku, Sakura-shi, Chiba Prefecture Inside the Central Research Laboratory, Noda Co., Ltd. (72) Inventor Koichi Soeda 2-4-2 Daisaku, Sakura-shi, Chiba Prefecture (72) Inventor Kenjiro Makino 2-517 Sakuragaoka, Nobeoka-shi, Miyazaki Prefecture F-term (reference) DE17Y DE29Y 4G012 PB16 PB31 PB32 PB36 4J002 BG011 BG031 BH001 CH022 DE237 DJ007 DJ037 EF026 EF056 EG016 EG026 EG036 4J027 AC03 AC04 AC06 AJ01 AJ08 BA02 BA06 BA07 CA09 CA14 CA18 CA24 CA36

Claims (6)

[Claims] 1. A powdery cement containing particles containing a polycarboxylic acid-based polymer compound having a polyalkylene glycol chain and one or more selected from a polyalkylene glycol and a fatty acid having 8 to 22 carbon atoms. Dispersant. 2. Particles comprising a polycarboxylic acid-based polymer compound having a polyalkylene glycol chain, an inorganic powder, and one or more kinds selected from polyalkylene glycol and a fatty acid having 8 to 22 carbon atoms. A powdery cement dispersant to be contained. 3. The polycarboxylic acid-based polymer compound having a polyalkylene glycol chain is one or more selected from a (meth) acrylic acid-based copolymer and a maleic acid-based copolymer. Or the powdery cement dispersant according to 2 above. 4. The powdery cement dispersant according to claim 1, wherein the polyalkylene glycol is polyethylene glycol having an average molecular weight of 1,000 to 200,000 and / or polypropylene glycol having an average molecular weight of 2,000 to 6,000. 5. The powdery cement dispersant according to claim 1, having an average particle size of 5 to 2000 μm. 6. A cement composition comprising the powdery cement dispersant according to any one of claims 1 to 5 and cement.