JPS59190245A - Cement fluidizing composition - 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 relates to cement fluidizing compositions.

More specifically, the present invention relates to a cement fluidizing composition that can improve the fluidity of concrete, mortar, cement paste, etc., which are hydraulic cement compounds, and improve the workability and workability thereof. It is widely known that the most basic condition for improving the durability and strength of a compound is to reduce as much as possible the amount of water required for kneading and mixing.

However, reducing the amount of water required for mixing lowers the fluidity of the hydraulic cement mixture and improves its workability.
Therefore, in order to reduce the amount of water required for mixing without impairing workability, so-called water reducers are generally used.

The water reducing effect of water reducing agents used for this purpose is as follows:
It is thought that this phenomenon occurs when fluidity is imparted by dispersing cement particles, and in order to further improve the water-reducing effect, it is necessary to find a more excellent dispersant for cement particles.

Conventionally, it was reported in the 4th year of the Japanese Patent Publication that naphthalene sulfonic acid/formaldehyde condensates or melamine sulfonic acid/formaldehyde condensates are effective for dispersing cement particles.
Publication No. 1-11787 or Special Publication No. 52-1899
There is a strong desire to develop an inexpensive water reducing agent.

Under these circumstances, the inventors of the present invention conducted intensive studies to find a water reducing agent that has higher cement fluidity, is inexpensive, and is industrially advantageous. However, when inexpensive sodium silicate, which has been confirmed in experiments by the present inventors to have no water-reducing effect, is used in combination with the melamine sulfonic acid/formaldehyde condensate, surprisingly The inventors have discovered that the condensate can further improve the inherent fluidity-improving effect of cement, and have completed the present invention.

That is, the present invention provides a cement fluidizing composition containing a melamine sulfonic acid/formaldehyde complex or a salt thereof and sodium silicate in a weight ratio of 100:2 to 200.

When the composition of the present invention is added to a hydraulic cement mixture, its fluidity is greatly improved and its water-reducing effect becomes remarkable. In other words, in order to obtain the same water reduction effect as the conventional melamine sulfonic acid/formaldehyde condensate, a part of the condensate can be replaced with extremely inexpensive sodium silicate, which has a very large economic effect.

The melamine sulfonic acid/formaldehyde condensate used in the present invention can be prepared by a method known per se.
Publication No. 8991, West German Patent Publication No. 167101.7
For example, melamine, formaldehyde, and potassium sulfite are mixed in a molar ratio of l:
2-8.5: 0°9-1.5 in aqueous solution, temperature 50°C ~
The reaction was carried out under conditions of 80°C and pH 10-13, adjusted to pH 2-4.5 with dilute mineral acid, and reacted at 30-60°C to 30-90°C.
Obtained by condensation for minutes.

The melamine sulfonic acid/formaldehyde condensate used in the present invention is not particularly limited and can be obtained by any of the methods described above or other known methods, but it is preferable that the unreacted melamine sulfonic acid content in the condensate is 8
The content of the melamine sulfonic acid/formaltehyde condensate having three or more melamine nuclei is 70% by weight or more. Among these composites, the viscosity of a 40-weight aqueous solution is 25° (10 to 1000 cps
Preferably.

Examples of the condensate residue include salts of alkali metals such as sodium and potassium, or alkaline earth metals such as calcium.

The sodium silicate used in the present invention is generally called hydraulic lath, and is represented by the chemical formula of Na0-nsic)z @XI (20, for example, JIS K], /1.08). −・(Acid sorter (hydraulic lath)
can also be used.

In producing the cement fluidizing composition of the present invention, the mixing ratio of the melamine sulfonic acid/formaldehyde condensate and sodium silicate is 100% of the former and 2 to 2% of the latter.
00 parts by weight, preferably 8 to 100 parts by weight. If the latter mixing ratio is less than 2 parts by weight, the effect of adding sodium silicate will not be sufficiently exhibited, while if it exceeds 200 parts by weight, it will absorb carbon dioxide gas from the air due to the unique properties of sodium silicate. This results in the formation of insoluble components and impairs the stability of the composition.

The form of the composition of the present invention is not particularly limited, and it can be used in the form of a dry powder or an aqueous solution. When used in the form of an aqueous solution, it is usually preferable to use an aqueous solution with a solid content of 60 kg or less. Various additives commonly used in this technical field, such as curing accelerators, retarders, and air transport agents, may be added to the composition of the present invention.

The composition of the present invention may be added to cement and mixed in advance,
Or added to the water required for mixing when preparing hydraulic cement mixtures such as concrete, mortar, and cement paste.1. It can be used as Furthermore, the melamine sulfonic acid/formaldehyde condensate and the sodium silicate may be added to the cement or the water required for mixing as described above so as to achieve the mixing ratios described above.

The amount of the composition of the present invention added to cement is
Hydraulic cement mixture or melamine sulfonic acid/
The type of formaldehyde condensate, furthermore melamine sulfonic acid, /Pol 005-5% by weight, preferably 0.2-2
The Sensito fluidizing composition of the present invention has an extremely high cement fluidizing effect, and therefore can significantly reduce the amount of water required for mixing without impairing the workability and workability of hydraulic cement mixtures. By reducing the amount, its strength and durability can be improved.

Next, the present invention will be explained in more detail using examples. In the examples, "part" and "cross" are parts by weight and parts by weight, respectively.

Silkworm example melamine, pormaldehyde, and sodium sulfite,
The molar ratio was adjusted to 1:3.2:1.2, and then the temperature was raised to 60°C and adjusted to pH 1O15 with a caustic sorter aqueous solution, and heating was continued until sodium sulfite was no longer detected.

After that, the pH was adjusted to 3.5 with dilute sulfuric acid, and the pH was adjusted to 9 at 50°C.
The total reaction was allowed to proceed for 0 minutes. After the reaction, the pH was adjusted to 9.0 with an aqueous solution of caustic soda, and water was added to adjust the solid content to 20%.

The viscosity of this product at 20°C is 15 cp, and the sl-I of melamine sulfonic acid/formaldehyde condensate
It contained 90.5% of trinuclear or higher components of Jium salt.

Example 1 To 100 parts of the melamine sulfonic acid/formaldehyde condensate (hereinafter referred to as S condensate) obtained in the reference example, J 151 silicate sorter (manufactured by Fuji Ishigakusha) was added to the
Cement fluidizing compositions were prepared by adding and mixing them in the proportions shown in the table.

Water was added to 275s of each prepared composition to give 1402s.
water/cement = 27.5%) and 500 parts of ordinary Portland cement (manufactured by Onoda Cement Co., Ltd.) (Addition of cement fluidizing composition to cementffi 0
．． After stirring in a mortar mixer for 3 minutes, the cement paste was subjected to vertical vibrations of 15 times/15 seconds on a flow table, and the spread (flow value) of the cement paste was measured.

hmm The results are shown in Table 1.

ゝ＼１＼、＼、＼- Table 1 Example 2 The melamine sulfonic acid/bormaldehyde composite obtained in Reference Example 1 and JISI sodium silicate were added to cement in the proportions shown in Table 2. Each of these was added to 500 parts of ordinary Portland cement to give a concentration of 27.5%, and the same procedure as in Example (2) was carried out to measure the flow value. The results are shown in Table 2.

Table 2 Example 8 A cement fluidizing composition was prepared using 100 parts of a commercially available melamine sulfonic acid/formaldehyde condensate (Melmen F-10, manufactured by Showa Denko) and 20 parts of JISI sodium silicate, The flow value was measured in the same manner as in Example 1 and found to be 220 am. -10,000 Melment F
When -10 and sodium silicate were used alone, the flow values were 190 and 140, respectively.

Claims (1)

[Claims] ■) Cement fluidizing composition 1 containing a melamine sulfonic acid/formaldehyde condensate or its salt and sodium silicate in a weight ratio of 100:2 to 200.
．． 2) The cement fluidizing composition according to claim 1, wherein the NaO2 and 5in2 contents of the sodium silicate are 8 to 35 weight kems and 20 to 70% by weight, respectively.