JPS5884160A - Cement dispersant - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a cement dispersant for hydraulic materials such as cement paste, mortar, and concrete, and more preferably, a cement dispersant for hydraulic materials such as cement paste, mortar, and concrete. This invention relates to a cement dispersant that provides high water-reducing, long-lasting workability and high strength.

Generally, when manufacturing pastes, solutar, concrete, etc. using cement, dispersants are used to improve their fluidity, and dispersants such as those mainly based on lignin sulfonates are used. , those based mainly on formalin condensates of β-naphthalene sulfonate, and those based on formalin high condensates of melamine having sulfonic acid residues, but these have the following drawbacks.

In other words, those mainly composed of lignin sulfonate are
Since short-term strength development is poor, this is improved by using calcium chloride, sodium sulfate, amines, etc., but on the other hand, the reinforcing steel corrodes, crystals precipitate in the winter, and air entrainment problems occur. , curing retardation, false setting, etc., so it is not possible to reduce the amount of water by using a large amount of it. In addition, β-naphthalene sulfonate formalin condensation products and formalin high condensation of melamine with sulfonic acid residues Products that are mainly made up of water can provide good workability with a low unit amount of water, but this requires a large amount of water to be added, and moreover, the workability drops significantly in a short period of time [7] , sufficient care must be taken when using it. For example, when these additives are used, the workability of concrete after mixing rapidly decreases, so handling operations must be completed within a very short period of time. If this additive is used in the production of ordinary ready-mixed concrete, it cannot be transported by concrete mixer truck or the like. Furthermore, even when manufacturing concrete products in a factory, it is necessary to pay sufficient attention to the decrease in workability of concrete after cross-contact. This cement dispersant contains as main components salts of a formalin cocondensate of sulfonic acid and a compound capable of cocondensation therewith, and amine acids.

The present invention will be explained in detail below. First, salts of formalin cocondensates (hereinafter referred to as cocondensates) of alkylnaphthalene sulfonic acids and compounds that can be cocondensed with the alkylnaphthalene sulfonic acids according to the present invention will be explained. The alkylnaphthalene sulfonic acid preferably has an alkyl group having 1 to 4 carbon atoms. The reason for this is that as the number of carbon atoms increases, air entrainment increases, which adversely affects strength development. Examples of the alkyl group include methyl, propyl, inzotetravir, butyl, and imbutyl.

Compounds that can be co-condensed with this alkylnaphthalene sulfonic acid include polycyclic aromatic compounds such as naphthalene and anthracene, and their sulfonated products, benzene, toluene,
One or more types selected from phenol, benzene derivatives of sodium benzoate, and sulfonated products thereof.

The amount of alkylnaphthalene sulfonic acid is preferably 0.05 to 0.5 mol per mol of all aromatic compounds in the cocondensate, or 0.1 to 0.6 mol per %. If the amount of alkylnaphthalene sulfonic acid is significantly smaller than 0.05 mol per mol of the wholly aromatic compound, the effect of improving workability etc. will be small, and if it exceeds 0.5 mol, the air entrainment will be unnecessarily large. There is no negative effect on strength development.

The salts of the co-condensate are alkali salts and/or alkaline earth salts, specifically sodium salts, potassium salts, calcium salts, and mixed salts thereof.

Examples of the method for producing salts of the cocondensate according to the present invention include:
It can be produced by condensing a sulfonated product of a mixture of alkylnaphthalene and naphthalene, or a sulfonated product obtained by reacting alcohol and naphthalene in sulfuric acid with formalin and neutralizing it with a base.

Next, humic acids will be explained. The amine acids used in the present invention include natural amine acids and nitrofumic acids. 0Natural 7-minic acids are substances represented by naturally occurring corrosive acids, and are present in aged charcoal and soil. It is a substance. Nitrohumic acids are amine acid-like substances obtained by acid decomposing coal with nitric acid to a low degree to reduce the molecular weight and increase the number of functional groups. All of these amino acids are effective, but water-insoluble substances are less effective. The ratio of salts and humic acids in the co-condensate is important for achieving a high water loss rate, long-lasting workability, that is, prevention of fluidity decline over time, and From the viewpoint of improving strength development, it is desirable that the weight ratio of the latter to the former be 1:0.03 to 2. The reason for this is that if the proportion of amine acids is extremely small, the sustainability of workability will be accelerated and the fluidity will deteriorate over time, and if the proportion of humic acids is increased, the sustainability of workability will be better. On the other hand, this is because the water-reducing property decreases and curing is delayed, resulting in insufficient strength development.

The additive ratio of the cement dispersant of the present invention to cement is usually about 0.01 to 3 inches. Furthermore, the cement dispersant of the present invention can be used in combination with water reducers, retarders, hardening accelerators, MuE agents, Mu1 water reducers, swelling agents, etc. that have been commonly used as admixtures for cement without any problem. There isn't.

The cement dispersant of the present invention may be added by any of the pre-addition method, post-addition method, and divided addition method.In particular, when using the pre-addition method, the change in workability over time is small compared to conventional dispersants. It is advantageous. The pre-addition method refers to a method in which a cement dispersant is added before or during the mixing of hydraulic materials, and the post-addition method refers to a method in which a cement dispersant is added after kneading hydraulic materials for a short time, and the divided addition method This is a method in which the cement dispersant is added to the hydraulic material in portions at regular intervals.

As a cement for combining hydraulic materials, ordinary, early strength,
Super early strength, moderate heat, white Portolan R cement, mixed cement containing silica, flyfish, granulated blast furnace slag, etc., expanded cement, rapid hardening cement with calcium aluminate and gypsum, alumina cement, and more. Examples include cement made of granulated blast furnace slag and an alkali stimulant such as hydroxide, oxide, carbonate, or sulfate of an alkali metal or alkaline earth metal. The material is cast-in-place concrete for civil engineering and construction, etc., and is produced by compacting in parallel, vibrating compaction, or centrifugal compaction, followed by heat curing such as room temperature curing, steam curing, or autoclave curing. It can be used as concrete for manufacturing factory products such as piles, poles, concrete pipes, box culverts, U-grooves, steel pipe concrete composites, blocks, etc.

As explained above, the present invention is a cement dispersant containing as main components salts of a formalin cocondensate of an alkylnaphthalene sulfonic acid and a compound capable of cocondensing therewith, and heptaminic acids. By imparting high water-reducing properties and long-lasting workability to hydraulic materials, it is possible to produce high-strength hydraulic materials with low air entrainment and almost no curing delay.

The present invention will be explained below with reference to Examples.

Note that all parts and parts in this specification are expressed on a weight basis.

Example 1 10 g of a cement dispersant having the proportions shown in Table 1 was dissolved in water, and 2.0 Kf of ordinary Portland cement was dissolved in water.
, 6.0 Kt of Ubukawa sand for Sagami was added and mixed for 1 minute at 60°C using a hand mixer to mix the mortar. We measured the mini-slump flow of this mortar immediately after mixing the soil,
The mortar was re-kneaded by varying the water tt until the flow value reached 260 m, and the water-cement ratio W/O was determined from the required amount of water at this time and is shown in Table 1. 7 days immediately after the crosstalk-
The mortar with a value of 260 remains silent after the flow measurement,
The mixture was kneaded for 15 seconds using a hand mixer every 15 minutes to establish a mini-slump flow. Mini slump flow is 15m (upper opening diameter 5C111, lower opening diameter 10cm)
The slump cone was immediately pulled up after filling the slump cone (cIft) with mortar, and the spread of the mortar at this time was measured. The results will be shown to the first group. Experiments 3 to 5 are based on the present invention.The examples (Experiments A6 to 5) showed better water reduction properties, lower flow over time, and compression after one day compared to the comparative examples (Experiments 7fL1 to 2). It is clear that the strength development is well-balanced and excellent.

Note in Table 1) The salts of the cocondensate are the sodium salt of methylnaphthalenesulfonic acid-naphthalenesulfone #I @ formalin cocondensate (methylnaphthalene (-EJ-)/naphthalene (-W) = 18.2/81 .8') and was manufactured as follows.

100 g of .beta.-methylnaphthalene and 400 g of naphthalene were added to 600 g of 98% concentrated sulfuric acid and sulfonated at 160 DEG C. for 1 hour, and then 610 g of 67% formalin was added dropwise at 100 DEG C. for 5 hours. At this time, when the viscosity increased, a small amount of water was added to lower the viscosity and the condensation alloy was continued. The obtained cocondensate was subjected to liming and sodation in a conventional manner to obtain a sodium salt.

Note 2) Aminated steel is made of nitrofumic acid sodium salt (
(manufactured by Nihon San Kagaku Kogyo M).

Example 2 Additives having the composition shown in Table 2 were dissolved in 6.24 Kf of water, and 12 # of ordinary Portland cement and 3 # of Yugawa sand for Sagami were dissolved in 6.24 Kf of water.
Mix concrete using 1.7 Kf and 42 Kf of Ubukawa gravel for Sagami (less than 25 cm), and reduce the slump after mixing.
I+ was established. Next, the concrete was remixed every #m120 minutes and the slump was remeasured, and its change over time was measured over a period of 60 minutes.The results are shown in Table 2. Experiments Muro and 7 are of the present invention.

From Table 2, the examples (Experiments A6-7) have an initial slump,
It is clear that this sample is superior to the comparative example (Experiment A8) in terms of the balance between slump reduction over time and strength development performance.

Patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] A cement dispersant comprising salts of a formalin cocondensate of an alkylnaphthalene sulfonic acid and a compound cocondensable therewith, and humic acids as main components.