JPH0153218B2 - - Google Patents

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 specifically, a pulp containing a salt of a naphthalene sulfonic acid formalin condensate and a lignin sulfonate with a reduced content of low molecular weight substances. A wastewater treatment product containing as a main component a salt of a copolymer of an ethylenically unsaturated dicarboxylic acid and a hydrocarbon compound having a double bond, or a product in which an antifoaming agent is further added to these components. Contains as a main component,
This product relates to a cement dispersant that provides high water-reducing properties, sustainable workability, and high strength. Generally, dispersants are used to improve the fluidity of pastes, mortars, concrete, etc. using cement. - There are those mainly based on a formalin condensate of naphthalene sulfonate, and those mainly based on a high formalin condensate of melamine having a sulfonic acid residue, but these have the following drawbacks. In other words, lignin sulfonate-based products have poor short-term strength, so they are used in combination with calcium chloride, sodium sulfate, amines, etc. to improve this, but on the other hand, they may corrode the reinforcing steel. In winter, crystals precipitate, and furthermore, it has air entrainment, curing retardation, and false setting, so it cannot be used in large quantities to reduce the amount of water. In addition, products mainly composed of formalin condensates of β-naphthalene sulfonate and formalin high condensates of melamine having sulfonic acid residues can provide good workability with a small amount of water per unit; have to do more,
Moreover, 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 the concrete after mixing rapidly decreases, so it is necessary to complete the handling work within an extremely short period of time. When this additive is used in the production of normal ready-mixed concrete, it cannot be transported by concrete mixer trucks or the like. Furthermore, even when manufacturing concrete products in a factory, it is necessary to pay sufficient attention to the reduction in workability of concrete after mixing. The present invention aims to solve these drawbacks, and the first invention is a salt of naphthalene sulfonic acid formalin condensate, the content of components having a molecular weight of 2000 or less in the total solid content is 30%. Contains as a main component a treated pulp effluent containing the following lignin sulfonate as a main component, and a water-soluble salt of a copolymer of an ethylenically unsaturated dicarboxylic acid and a hydrocarbon compound having a double bond. The second invention is a cement dispersant comprising as a main component an antifoaming agent added to these components. The present invention will be explained in detail below. First, the salt of the naphthalene sulfonic acid formalin condensate according to the present invention will be explained. This is not limited to single condensates of naphthalene sulfonic acid, but also polycyclic aromatic compounds such as naphthalene, alkylnaphthalene, and anthracene, or their sulfonic acid compounds, and benzene derivatives such as benzene, toluene, phenol, benzoic acid, etc. It may be a formalin cocondensate with one or more compounds selected from sulfonic acid compounds and the like. Salts of these formalin condensates include alkali salts and/or alkaline earth salts, specifically sodium salts, potassium salts, calcium salts, and mixed salts thereof. As a commercially available salt of naphthalene sulfonic acid formalin condensate, the product name ``Mighty'' (Kao Soap
(manufactured by Takemoto Yushi Co., Ltd.), product name: "Pole Huain" (manufactured by Takemoto Yushi Co., Ltd.)
(manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), product name “Ceroflo-R155” (Daiichi Kogyo Seiyaku Co., Ltd.)
Co., Ltd.). Next, we will explain the pulp effluent treatment product (hereinafter simply referred to as the pulp effluent treatment product), which is mainly composed of lignin sulfonate in which the content of components with a molecular weight of 2000 or less in the total solid content is reduced to 30% or less. do. In the present invention, the reason why the content of components with a molecular weight of 2,000 or less in the treated pulp waste liquid is limited to 30% or less is that the content of components with a molecular weight of 2,000 or less is 30% or less.
This is based on the fact that when a cement dispersant containing more than 5% of the total amount of carbon dioxide is used as a cement dispersant, hardening retardation is large and dispersibility becomes low. The molecular weight of the lignin sulfonate can be measured by gel permeation chromatography using silica gel that has been subjected to hydrophilic treatment using standard polystyrene sulfonic acid with a known molecular weight as a standard. In order to obtain such a treated pulp waste liquid, the pulp waste liquid may be used as a raw material, and it may be subjected to various chemical or physical treatments to remove low molecular components. As the raw material, sulfite pulp waste liquid is preferable, and coniferous pulp waste liquid is preferable. Further, as a method for removing low molecular weight components, a dialysis method using a cellulose membrane can be employed in the laboratory, but a method such as an ultrafiltration method is preferable in an industrial setting. In particular, when pulp wastewater is treated by ultrafiltration, it is advantageous because any component can be fractionated according to its molecular size. Next, a water-soluble salt of a copolymer of an ethylenically unsaturated dicarboxylic acid and a hydrocarbon compound having a double bond (hereinafter referred to as a polyhydric carboxylic acid copolymer) will be explained. This is a necessary component to synergistically prevent the deterioration of workability over time by working together with the above two components. A mixture preferably in a molar ratio of 1:1 to 3:1 is copolymerized using a polymerization initiator, and the resulting copolymer is hydrolyzed with an alkali metal base such as sodium or potassium or ammonia. or by partially esterifying these. Examples of ethylenically unsaturated dicarboxylic acids include maleic acid, itaconic acid, and citraconic acid. Maleic acid is preferably a derivative thereof, and hydrocarbon compounds having double bonds include styrene, methylstyrene, etc. styrenic compounds and <sub>C4</sub> to <sub>C16</sub> chain and/or cyclic olefin hydrocarbons, specifically butene-1, butene-2, isobutylene, pentene-1, pentene-2, 2-methyl- Butene-1, 2-methyl-butene-2, 4-methyl-pentene-1, hexene-1, etc., cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene,
Cyclopentadiene, dicyclopentadiene, 2
-ethyl-5-norbornene, 2-cyano-5-
Examples include norbornene and 2-acetyl-5-norbornene. Among these hydrocarbon compounds, styrene compounds are highly effective. The ratio of the salt of the naphthalene sulfonic acid formalin condensate to the treated pulp wastewater is determined by the weight of the latter relative to the former, from the viewpoint of high water-reducing properties and sustainable workability, that is, prevention of fluidity decline over time, and improvement of strength development. A ratio of 95:5 to 5:95 is desirable. The reason for this is that when the proportion of the salt of the naphthalene sulfonic acid formalin condensate exceeds this range, the sustainability of workability deteriorates and the fluidity decreases over time, and when the proportion of the pulp wastewater treated product exceeds this range, This is because curing is delayed and strength development becomes insufficient. In addition, the proportion of the polyhydric carboxylic acid copolymer is the total amount of the former two components by weight.
5 to 95 to 95 to 5, preferably 5 to 95 to 50
~50 range. If the proportion of the polyhydric carboxylic acid copolymer is significantly higher or lower than this, the strength development will be insufficient or false coagulation will occur. If a cement dispersant containing the above-mentioned naphthalene sulfonic acid formalin condensate salt, pulp wastewater treatment product, and polyhydric carboxylic acid copolymer as main components is used, high water-reducing properties and sustainability can be achieved in hydraulic materials. It has the effect of being able to produce a high-strength hydraulic material that provides a certain level of workability and has almost no curing delay. The second invention is the cement dispersant of the first invention further containing an antifoaming agent, thereby further improving the strength development while retaining the characteristics of the cement dispersant of the first invention. Can be done. Antifoaming agents used in the present invention include partial esters of polyhydric alcohol fatty acids, block polymers of polypropylene oxide and polyethylene oxide, higher alcohols, silicones, and mixtures thereof. Specific commercially available products include:
Examples include Nippon Oil & Fats Co., Ltd.'s product name ``Days Home'' and Toshiba Silicone Company's product name ``TSA732.'' The addition rate of the cement dispersant of the present invention to cement is usually about 0.05 to 1%. Furthermore, the cement dispersant of the present invention can be used in combination with water reducing agents, retarders, hardening accelerators, AE agents, AE water reducing agents, swelling agents, etc. that have been commonly used as admixtures for cement without any problem. do not have. Currently, there is a strong demand for the development of better additives to prevent the consistency of hydraulic materials from deteriorating over time, and the present invention meets this demand. Therefore, the cement dispersant of the present invention may be added by any of the pre-addition method, post-addition method, and divided addition method, and it is particularly advantageous to use the pre-addition method. 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. The cement used to prepare hydraulic materials includes normal, early strength, ultra early strength, medium heat, white Portland cement, mixed cement containing silica, fried wood, granulated blast furnace slag, etc., expanded cement, calcium aluminate and stone. Examples include rapid hardening cement in which Kou is present, alumina cement, and cement made of granulated blast furnace slag and alkaline irritants such as hydroxides, oxides, carbonates, and sulfates of alkali metals or alkaline earth metals. It will be done. The hydraulic material to which the cement dispersant of the present invention has been added can be used as cast-in-place concrete for civil engineering and construction purposes, and after compaction, vibration compaction, or centrifugal force compaction, it is cured at room temperature, steam cured, or heated in an autoclave. It is used as concrete for manufacturing factory products such as piles, poles, concrete pipes, box culverts, U-shaped grooves, steel pipe concrete composites, and blocks. The present invention will be explained below with reference to Examples. Note that all parts and percentages described in this specification are expressed on a weight basis. Example 1 The additives shown in Table 1 were dissolved in a predetermined amount of water,
Add 2.0 kg of ordinary Portland cement and 6.0 kg of river sand from the Sagami River to this, and mix at 30°C using a hand mixer.
The mortar was kneaded by mixing for 1 minute. The mini-slump flow of this mortar was measured immediately after mixing, and the mortar was re-kneaded by varying the amount of water until the flow value reached 260 mm.The water-cement ratio W/C was calculated from the required water amount at this time and is shown in Table 1. It was shown to. The mortar with a flow value of 260 mm immediately after kneading was allowed to stand after flow measurement, and was kneaded for 15 seconds with a hand mixer every 15 minutes to measure mini-slump flow.
Mini slump flow is 15cm high (direct diameter of the upper opening 5cm)
After filling mortar into a slump cone with a diameter of 10 cm (diameter 10 cm from the bottom opening), the slump cone was immediately pulled up and the spread of the mortar was measured. The results are shown in Table 1. As is clear from Table 1, the Examples are superior to the Comparative Examples in terms of the balance of performance in water reduction, flow change over time, and strength development. The additive symbols shown in Table 1 represent the following components. N: Soda salt of β-naphthalenesulfonic acid formalin condensate L: Ultrafiltered sulfite pulp effluent (using an ultrafiltration membrane with a separation limit of MW 6000) Soda salt of polymer Y: Soda salt of a copolymer of styrene and maleic anhydride at a molar ratio of 1:1 S: Commercially available silicone antifoaming agent (trade name "TSA732")

[Table] Example 2 Additives with the composition shown in Table 2 were dissolved in 6.24 kg of water, 12.0 kg of ordinary Portland cement, 31.7 kg of river sand from the Sagami River, and 42.0 kg of river gravel from the Sagami River (25 mm or less).
6.3 kg of water was added to mix concrete with a target slump of 18 cm. The additives were added in advance to a portion of the mixing water at the beginning, and the slump was adjusted using the final adjustment water. Immediately after mixing, concrete with a slump of 18 cm was allowed to stand, and the slump was re-measured every 20 minutes after being remixed every 20 minutes, and changes over time were measured over 60 minutes. From Table 2, Examples have water reduction properties, initial slump,
It is clear that the performance balance of slump change over time and strength development performance is superior to the comparative example.

[Table] It is a thing.

Claims (1)

[Scope of Claims] 1. A treated pulp effluent mainly composed of a salt of a naphthalenesulfonic acid formalin condensate, ligninsulfonic acid in which the content of components with a molecular weight of 2000 or less in the total solid content is 30% by weight or less, and a cement dispersant containing as a main component a water-soluble salt of a copolymer of an ethylenically unsaturated dicarboxylic acid and a hydrocarbon compound having a double bond. 2 Salts of naphthalene sulfonic acid formalin condensates, treated pulp effluents whose main component is lignin sulfonic acid with a content of components with a molecular weight of 2000 or less in the total solid content of 30% by weight or less, ethylenically unsaturated dicarboxylic acids A cement dispersant comprising, as main components, a water-soluble salt of a copolymer of and a hydrocarbon compound having a double bond, and an antifoaming agent.