JPS58194770A - Cement additive - 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 provides a cement additive that is useful for improving the loss of fluidity of hydraulic materials such as cement paste, mortar, and concrete over time. The present invention relates to a cement additive containing polyvinyl alcohol copolymerized with dimethyl malate or its alkaline hydrolysis MqlJ and a cement dispersant.

Conventionally, VCkment dispersants have been used to improve the fluidity of hydraulic materials. As a cement dispersant,
For example, those mainly consisting of increased lignin sulfone rII, β
-Naphthalene sulfone #formalin condensation @rchiyx There are some that are based mainly on formalin condensates of melamine having sulfonic acid residues, but these have the following drawbacks.

In other words, those mainly composed of lignin sulfonate are
Short term Il! Since the J degree is poor, it is used in combination with enriched calcium, sodium sulfate, amines, etc. to store electricity, but it has the disadvantage that workability decreases in a short period of time during construction in the summer.

In addition, β-naphthalene sulfone #I formalin condensates and formalin high condensates of melamine with sulfonic acid residues can provide good workability with a small amount of water; In addition, workability decreases significantly in a short period of time, so sufficient care must be taken when using it. For example, when these additives are used, the workability of concrete after mixing rapidly decreases, so it is necessary to complete the composting operation within a very short period of time. When this decorative calorific agent is used in the production of normal ready-mixed concrete, it cannot be transported using a concrete mixer or the like. Furthermore, even when manufacturing concrete products in a factory, it is necessary to pay sufficient attention to a decrease in the workability of the concrete after mixing.

As a result of various studies aimed at resolving these drawbacks, the present inventor found that it is sufficient to use these cement dispersants in combination with polyvinyl alcohol obtained by copolymerizing dimethyl malate or its alkaline hydrolyzate. , has completed the present invention.

The present invention will be explained in detail below.

Examples of preferred cement dispersants applicable to the present invention are as follows.

1. Base yarn of naphthalene sulfonic acid formalin condensate This is a single naphthalene sulfonic acid - hardware K11jd
Polycyclic aromatic compounds such as naphthalene, alkylnaphthalene, and anthracene, or their sulfo/acid combinations, benzenes such as benzene, toluene, phenol, and benzoic acid, or their sulfonic acid compounds, etc. It may also be a formalin co-condensate with one or more (t' compounds). Examples of these formalin condensation salts include alkali salts and/or alkaline earth salts, and specifically are sodium salts, potassium salts, calcium salts and mixed salts thereof.

Commercially available products of naphthalene sulfonic acid formalin condensate include the product name "Mighty" (manufactured by Kao Soap Co., Ltd.), the product name "1 Ball Fine" (manufactured by Monomoto Yushi C Co., Ltd.), and the product name "Cellflow R155J (manufactured by Monomoto Yushi C Co., Ltd.). -manufactured by Kogyo Seijyo Co., Ltd.).

2. As a base commercial product of a formalin high condensate of melamine having sulfonic acid residues, the product name is "Melment" (Showa Denko K.K.)
), product name rNL-4000J (manufactured by Nisso Master Builders Co., Ltd.), and product name ``np-20J (manufactured by El So Master Builders Co., Ltd.).

6. Lignin sulfone #! Commercially available salt yarn products include the trade name "Hozolith/%5 LJ" (made by Nikka Master Builders Co., Ltd.) and the trade name "F Sunflow Hi" (made by Deyu Kokusaku Pulp Co., Ltd.).

The amount of the above-mentioned cement dispersant used can be freely selected depending on the required water-reducing properties and fluidity.

On the other hand, the dimethylmale()Y copolymerized vinyl alcohol or its alkaline hydrolyzate according to the present invention is necessary for maintaining the fluidity Y of cement paste, mortar, concrete, etc. in which the cement dispersant is used. It is an ingredient. The proportion of dimethyl malate contained in the copolymerized and modified polyvinyl alcohol is 0.1 to 5.
It is preferable to set the amount to about 0 mol. Furthermore, the dimethyl malate portion may be hydrolyzed with an alkali cosmogen such as sodium, potassium, or lithium.

To produce vinyl alcohol by copolymerizing dimethylmale()Y, for example, when vinyl acetate is polymerized in a methanol solution, dimethylmale()Y is continuously added and copolymerized, and then acetic acid All you need to do is saponify the vinyl part. Further, in order to further hydrolyze the dimethyl malate portion, an alkali such as caustic soda may be added in a methanol solution or an aqueous solution, and the reaction may preferably be carried out at a high temperature. In these, the degree of saponification rate and hydrolysis rate does not significantly affect the effects of the present invention, and any degree can be used.

The amount of dimethylmale()Y copolymerized phosphorivinyl alcohol or its alkaline hydrolyzate used is 0.01 to 0.5% by weight, preferably 0.02 to 0.2% by weight based on the cement. If the amount of electricity is -, the effect of maintaining fluidity will be greater.

The cement to which the product of the present invention is added is normal, early strength,
Super early strength, moderate heat, white Portland cement, silica, fly ash5. Mixed cement containing granulated blast furnace slag, expanded cement, calcium alinate and gypsum Y, hard cement, alumina cement, and hydration of granulated blast furnace slag and alkali metals or alkaline earth metals. Examples include cement made of alkaline irritants such as substances, oxides, carbonates, and sulfates.

The hydraulic material to which the cement additive V# of the present invention has been added can be used for cast-in-place concrete for civil engineering construction, etc., as well as for curing at room temperature, steam curing, or autoclave after being compacted, vibratory compacted, or centrifugally compacted. For example, pile, I
– concrete pipes, box culverts, U-shaped grooves,
Used as concrete for manufacturing factory products such as steel pipe concrete composites and zolotsk.

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

Example The additives shown in Table 1 were dissolved in a predetermined amount of water, and to this was added 2.0 U of ordinary Portolan R cement and 6.0 U of Sagami grade river sand.
The mixture was mixed for 1 minute at 30'C using a kg'Y Toguchi Eno-P mixer and kneaded with mortar. The mini-slump flow Y 5111 immediately after mixing of this mortar is constant L, the water amount is varied until the flow value becomes 26 ON, the mortar t'p4m is kneaded, and the water-cement ratio W10Y: is calculated from the required water amount at this time. Shown in the table. The mortar, which had a flow value of 260 wm immediately after cross-crossing, was allowed to stand still after the flow measurement, and every 15 minutes, the cross-crossing was performed for 15 seconds using a hand mixer. Mini slump flow is a slump cone with a height of 15α (upper opening 1 diameter 5cIL, lower opening 10cIL) immediately after filling with mortar! The potash of the mortar was measured and determined. The result is the first
Shown in the table.

t' Margin 1'7 Note that the symbols for additives shown in Table 1 represent the following components.

N: Soda salt of β-naphthalene sulfonic acid formalin condensate M: Soda salt of melamine sulfonic acid formalin condensate L: Sodium salt of lignin sulfonic acid M: Polyvinyl alcohol co-electrolyzed at a molar ratio of dimethyl maley) Y B Nidimethyl male) Polyvinyl alcohol copolymerized with Y molar ratio of 5 and 1 4 Hydrolyzed with NaOH 0 Nidimethyl male) Y molar ratio of 50 tatami Copolymerized polyvinyl alcohol D Nidimethyl maleate with a molar ratio of 501 Copolymerized polyvinyl alcohol Y hydrolyzed with NaOH

Claims (1)

[Claims] Polyvinyl alcohol obtained by copolymerizing dimethyl malate or its alkaline hydrolyzate, a cement dispersant, and t.
A government-owned cement additive.