JPH03187960A - Water-reducing agent for cement - Google Patents

Abstract

PURPOSE:To improve the flowability of a cement composition in a state reduced in the ageing change of the flowability by employing a bisphenol compound as a phenol compound in a small amount in a reducing agent containing an aromatic aminosulfonic acid.the phenol.formaldehyde condensate. CONSTITUTION:The water-reducing agent for cement contains as a main component the formaldehyde condensate of 4-aminobenzene sulfonic acid or a salt thereof and a bisphenol compound or salt thereof. The remained monomer (the aromatic aminosulfonic acid) in the aromatic aminosulfonic acid mixing agent is reduced, and polar groups and a steric property are imparted to the hydrophobic skeleton, thereby permitting to improve the flowability of the cement composition without deteriorating the flowability ageing reduction- preventing effect thereof. The bisphenol compound includes bisphenols A, S and F.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a water reducing agent used in cement compositions such as cement paste, mortar, and concrete. The present invention relates to a water reducing agent for cement that has improved workability with little reduction in workability.

[Conventional technology]

In recent years, workability has been improved in mortar work and concrete work, etc.9 Strength and durability have been improved.

Although various water reducing agents have been used for the purpose of improving various physical properties such as reducing cracking properties, a high performance AE water reducing agent is still required.

[Problem to be solved by the invention]

Conventionally, sulfonated melamine resin salts, polycarboxylic acid salts, naphthalene sulfonic acid formaldehyde high condensate salts, lignin sulfonate salts, etc. have been used as water reducing agents for cement, but sulfonated melamine resin salts have a small water reducing effect. , a large amount of addition is required, and polycarboxylate is
Although it has a large water-reducing effect, increasing the amount added causes a significant setting delay, resulting in insufficient curing in some cases. Naphthalenesulfonic acid formaldehyde high condensate salt has a large water reduction effect, little condensation delay, and low air entrainment, but
mortar.

The fluidity of concrete decreases significantly over time.

Although lignin sulfonate has a large water-reducing effect, there are problems such as a large amount of air being mixed in, which adversely affects the physical properties of mortar and concrete.

Recently, concrete admixtures containing aromatic aminosulfonic acids, phenols, and formaldehyde condensates have been developed (Japanese Unexamined Patent Publication No. 1-113419). This admixture is said to improve the consistency of cement compositions and reduce changes in fluidity such as slump loss over time, but further improvements such as a large amount of residual monomer during condensation are desired. It is rare.

[Means to solve the problem]

The present invention reduces the residual monomer (aromatic aminosulfonic acid) of an aromatic aminosulfonic acid-based admixture, and also provides a polar group and stericity to the hydrophobic skeleton, thereby preventing the fluidity from decreasing over time. The aim was to further improve the fluidity of cement compositions without impairing the properties, and this was achieved as a result of intensive research. The water reducing agent for cement of the present invention includes (1) 100 parts by weight of 4-aminobenzenesulfonic acid (sulfanilic acid) or a salt thereof (b) 20 to 150 parts by weight of a bisphenol compound or a salt thereof (C) 20 to 65 parts by weight of formaldehyde The main component is a formaldehyde condensate of a bisphenol compound and 4-aminobenzenesulfonic acid, which is produced by heating and condensing 4-aminobenzenesulfonic acid under aqueous conditions.

The bisphenol compound used in the present invention has the general formula [In the formula, X is OOH It is a compound represented by Kishi is used.

In order to produce the condensate, which is the main component of the water reducing agent of the present invention, it is necessary to carry out the condensation at the specific ratio mentioned above, and if it deviates from this, the water reducing property and fluidity will deteriorate.

The aging characteristics deteriorate.

In this condensation reaction, the influence of alkali is significant, and the addition rate of alkali is from 0.90 to 4-aminobenzenesulfonic acid molar ratio in the case of bisphenol compound/4-aminobenzenesulfonic acid-0,5/ ]. Preferably it is 1.30. If this value is exceeded, the amount of residual monomer (unreacted 4-aminobenzenesulfonic acid) increases rapidly.

The weight average molecular weight of the condensate, which is the main component of the water reducing agent of the present invention, was determined by gel permeation chromatography (G, P
, C,l is in the range of 10,000 to 50,000, and if it deviates from this range, the fluidity improving effect decreases.

[For production]

The condensate used in the present invention is a formaldehyde condensate of 4-aminobenzenesulfonic acid and phenol (hereinafter abbreviated as compound A) shown in JP-A-1-113419.
The fluidity improvement effect is remarkable compared to This is based on the following reasons in addition to the contribution of the structure of the bisphenol compound.

After the condensation reaction of compound A, about 10% of 4-aminobenzenesulfonic acid remains as a residual monomer.

This is thought to be because phenol tends to form a homopolymer, and as a result, unreacted 4-aminobenzenesulfonic acid tends to remain.

In this way, the condensation reaction of compound A using phenol involves side reactions, and due to the properties of phenol itself,
It is necessary to use complicated means such as a first step (reaction with a weak alkali) and a second step (reaction with a strong alkali).

- In the case of the formaldehyde condensate of 4-aminobenzenesulfonic acid-bisphenol compound, which is the main component of the water reducing agent of Rikiki's invention, the residual monomer is reduced to about 173 compared to the case of compound A.

This is thought to be because the bisphenol compound of the present invention is poorly soluble in water or alkali, and is less likely to produce a homopolymer as a side reaction than phenol.

In addition, the present invention using bisphenol compounds is characterized in that it is not necessary to use complicated reaction means as in the case of compound A using phenol.

The water reducing agent for cement of the present invention has a water reducing agent of 0.01 to 2
．． 0%, preferably 0.1-0.6%. If the amount is too small, the expected effect will not be obtained, and if it is too large, the cement will be excessively dispersed, causing a separation phenomenon, which is not preferable.

Cement is ordinary Portland cement, early strength cement, ultra early strength cement, and blast furnace cement.

Moderate heat cement, fly ash cement, sulfate-resistant cement, etc. are used. Also other cement additives, such as water reducing agents, air entraining agents.

Set retardant, waterproofing agent, swelling agent, silica hume.

It can also be used in combination with stone powder, etc.

〔Example〕

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

Example 1 A predetermined amount of the following substances was charged into a reaction vessel.

(I) 4-aminobenzenesulfonic acid 173.20 g (1 mol) (H) 2.2-bis(4-hydroxyphenyl)propane 114.15 g (0.5 mol) (m) 95% NaOH42,IIg, (1 mol) 768.74 g of water Next, to this solid-liquid suspension, (IV) 35% formaldehyde aqueous solution 1
71.43 g (2 mol) was added dropwise under reflux, and the resulting reaction mixture was stirred for 10 hours to obtain a transparent aqueous condensate solution.

Weight average molecular weight (My) of the obtained condensate and unreacted 4-
The amount of aminobenzenesulfonic acid is 24.950.
It was 2.8% (based on solid content).

The weight average molecular weight was measured by gel permeation chromatography (GPC) and converted using a pullulan standard. Unreacted 4-aminobenzenesulfonic acid was determined from the area ratio using a GPC differential refractometer. These are shown in Table-1.

Examples 2 to 6 Reaction conditions (I) (TI) (m) (I
V) 4-aminobenzenesulfonic acid, 2,2-bis(
A condensate was obtained in the same manner as in Example 1 except that the molar ratios of 4-hydroxyphenyl)propane, NaOH and formaldehyde were varied.

These results are shown in Table-1.

Table 1 Example 7 ~lO Predetermined amounts of the following four types of substances were charged into a reaction vessel.

(I) 4-aminobenzenesulfonic acid 173.20 g (1 mol) (II) 4.4'-dihydroxydiphenylmethane 10
0.12 g (0.5 mol) (III) 95% NaOH42.11 g (1 mol)
736.110 g of water Next, add 1 part of 35% formaldehyde aqueous solution to this solid suspension. ! ,
43 g (2 mol) were added under reflux and the reaction mixture was stirred under reflux for 10 hours to obtain an aqueous solution of the condensate.

The weight average molecular weight (My) of the obtained condensate and the amount of residual 4-aminobenzenesulfonic acid were 29.865.
It was 3.6% (based on solid content).

The weight average molecular weight was measured by gel permeation chromatography and converted using a pullulan standard. The residual 4-aminobenzenesulfonic acid was determined from the area ratio using a differential refractometer using gel permeation chromatography. The results are shown in Table 2.

In addition, Examples 8 to 11 were obtained by changing the bisphenol compounds as shown in Table 2 and carrying out the same procedure.

The results are also listed in Table 2.

2 Comparative Example 1 Mix specified amounts of the following four types of substances in a reaction container, and
The pH was adjusted to 8.11 with an aqueous NNaOH solution.

(■) 4-Aminobenzenesulfonic acid 173.20 g (1 mol) (II) Phenol 94. IOg (1 mol) (III) 95% NaOH42, IIg (1 mol) Water 721.97 g Next, (mV) 35% formaldehyde aqueous solution 1?
1.43 g (2 mol) was added under reflux and 7.5 g (2 mol) was added under reflux.
The mixture was stirred for an hour (first step).

The mixture was cooled to room temperature and adjusted to pH 1 with 20% aqueous NaOH.
The condensate was adjusted to 1.0 and refluxed for 3 hours (2nd step) to obtain a condensate.

The weight average molecular weight (My) of the obtained condensate and the amount of residual 4-aminobenzenesulfonic acid were 2 fl and 375.
It was 11.8% (based on solid content).

The weight average molecular weight was measured by gel permeation chromatography and converted using a pullulan standard. The residual 4-aminobenzenesulfonic acid was determined from the area ratio using a differential refractometer using gel permeation chromatography.

Comparative Examples 2-4 Reaction conditions (1) (II) (IV) 4-
A condensate was obtained in the same manner as in Comparative Example 1 by changing the molar ratios of aminobenzenesulfonic acid, phenol, and formaldehyde.

These results are shown in Table 3.

Table 3 (1+II+III): Water = OJ: 0.7 (weight ratio) [Test example] 0 Concrete test The consistency of concrete to which the water reducing agent of the present invention was added was compared to the consistency of concrete to which the water reducing agent of the comparative example was added. The slump loss (temporal change in fluidity) of concrete was compared with that of concrete.

The formulation is shown in Table 4.

For concrete, cement, aggregate, and water or water containing a water reducing agent were mixed for 3 minutes using a 1001 portable tilting mixer, and slump was measured immediately and 30.60 minutes later. The slump and air content of concrete were determined in accordance with JIS.

The measurement results are shown in Table 5, and the product of the present invention (example) was able to obtain the target slump with a lower addition rate than the conventional water reducing agent (comparative example). It shows that it is excellent.

5 Table 4 Mixture * C cement: Ordinary Portland cement Specific gravity 3
．． 16W Water; Tap water S Fine aggregate: Kashima river sand specific gravity 2.59F,
t 2.62G Coarse aggregate - Yamaguchi disease crushed stone Specific gravity 2.71
F, t li, 866 [Effects of the Invention] By using the product of the present invention, the desired fluidity can be obtained with a smaller amount added than conventional cement admixtures, and there is little change in fluidity over time ( A composition can be manufactured.

Table 5 *Weight% of cement

Claims (4)

[Claims] (1) A water reducing agent for cement whose main components are a formaldehyde condensate of 4-aminobenzenesulfonic acid or its salt and a bisphenol compound or its salt. (2) Bisphenol compounds have the following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, X in the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, ▲ Numerical formulas, chemical formulas, etc.
There are tables, etc. ▼, ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼
The water reducing agent for cement according to claim 1, which is a bisphenol compound represented by , ▲ numerical formula, chemical formula, table, etc. ▼ or -O-]. (3) 4-aminobenzenesulfonic acid or its salt 10
0 parts by weight and 20 to 20 parts of bisphenol compound or its salt
The water reducing agent for cement according to claim 1 or 2, characterized in that it contains a bisphenol compound/4-aminobenzenesulfonic acid condensate produced by condensing 150 parts by weight and 20 to 65 parts by weight of formaldehyde. (4) The water reducing agent for cement according to any one of claims 1 to 3, wherein the molecular weight of the condensate is 10,000 to 50,000.