A water retaining agent for pumping concrete and preparation method thereof

Abstract

The present invention proposes a water retaining agent for pumping concrete and a preparation method thereof, and belongs to the technical field of concrete water retaining agent. The raw materials for preparing the water retaining agent for pumping concrete include: 100 parts of an intermediate, 50-200 parts of epichlorohydrin, 2-10 parts of a NaOH solution and 10-50 parts of a perchloric acid solution, and the raw materials for preparing the intermediate include, by weight, 100 parts of methyl 2,5-dihydroxybenzoate and 150-450 parts of a monomer, wherein the monomer is an aliphatic monobasic acid substituted with an end amino group. The benzene ring of the water retaining agent prepared by the present invention is a rigid structure, and when concrete is pumped, the water retaining agent molecule is under shearing action, and due to the rigid structure of the benzene ring, the molecular chain stretches in the shearing direction, so that the water retaining agent molecule has no effect on the plastic viscosity of the concrete, and the pumpability is better.

Description

Technical Field

[0001] The invention belongs to the technical field of concrete water retaining agents, and in particular relates to a water retaining agent for pumping concrete and a preparation method thereof. Background Art

[0002] Concrete is prone to bleeding and segregation in engineering projects, which causes the concrete's working performance to decline and holes and exposed reinforcement to appear. In order to improve these defects of concrete, adding an appropriate amount of water-retaining agent can achieve the effect of improving workability, increasing cohesion, and preventing bleeding. Commonly used concrete water-retaining agents include cellulose, dextrin, guar gum, xanthan gum, and water-soluble polymers. These water-retaining agents will increase the plastic viscosity of concrete while resisting segregation, making concrete pumping more difficult.

[0003] Therefore, there is an urgent need to develop a water-retaining agent for pumped concrete that can increase the water retention of concrete when the concrete is static, reduce bleeding and segregation, and does not affect the plastic viscosity of the concrete. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a water retaining agent for pumping concrete and a preparation method thereof.

[0005] To achieve the above object, the present invention provides a water retaining agent for pumping concrete, the structural formula of which is:

[0006]

[0007] Among them, R is C4H8, C5H 10 、C6H 12 、C7H 14 、C8H 16 、C9H 18 , C 10 H 20 , C 12 H 24 or C 14 H 28 ; The value of n satisfies that the weight average molecular weight of the water retaining agent is 1 million to 3 million.

[0008] Furthermore, the water retaining agent for pumping concrete is prepared from raw materials including, by weight, 100 parts of an intermediate, 50-200 parts of epichlorohydrin, 2-10 parts of a NaOH solution, and 10-50 parts of a perchloric acid solution;

[0009] The raw materials for preparing the intermediate include, by weight, 100 parts of methyl 2,5-dihydroxybenzoate and 150-450 parts of monomers;

[0010] The monomer is an aliphatic monobasic acid substituted with an amino group at the terminal.

[0011] Further, the monomer includes one or more of 4-aminobutyric acid, 5-aminopentanoic acid, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 12-aminododecanoic acid and 14-aminotetradecanoic acid.

[0012] Furthermore, the concentration of the NaOH solution is 30 wt %, and the concentration of the perchloric acid solution is 30 wt %.

[0013] The present invention also proposes a method for preparing the water retaining agent for pumping concrete, comprising the following steps:

[0014] (1) methyl 2,5-dihydroxybenzoate, a monomer and a catalyst are stirred uniformly and heated for reaction. After the reaction is completed, the mixture is cooled to room temperature to obtain an intermediate;

[0015] (2) The intermediate obtained in step (1) is uniformly stirred with epichlorohydrin and a catalyst and heated for reaction, and then a NaOH solution and a perchloric acid solution are added dropwise. After the addition is completed, the mixture is kept warm and subjected to reduced pressure distillation to obtain the water retaining agent for pumping concrete.

[0016] Furthermore, in step (1), the heating reaction temperature is 80-150° C. and the time is 1-8 hours.

[0017] Furthermore, in step (1), the catalyst is one or more of dibutyltin dilaurate, dibutyltin oxide, tetrabutyl titanate and magnesium acetylacetonate, and the amount of the catalyst added is 2.5-17 parts by weight.

[0018] Furthermore, in step (2), the catalyst is triethylbenzyl ammonium chloride, and the amount of the catalyst added is 0.8-3 parts by weight.

[0019] Furthermore, in step (2), the heating reaction temperature is 60-90° C. and the time is 1-8 hours.

[0020] Furthermore, in step (2), NaOH solution and perchloric acid solution are added dropwise at 50-80°C.

[0021] Furthermore, in step (2), the NaOH solution is added dropwise for 1-5 hours, and the solution is kept warm for 1-3 hours after the addition is completed. The perchloric acid solution is then added dropwise for 0.5-2 hours, and the solution is kept warm for 1-2 hours after the addition is completed.

[0022] Compared with the prior art, the present invention has the following advantages and technical effects:

[0023] The following reactions occur during the preparation of the water retaining agent for pumped concrete of the present invention:

[0024]

[0025] Where R is C4H8, C5H 10 、C6H 12 、C7H 14 、C8H 16 、C9H 18 , C 10 H 20 , C 12 H 24 or C 14 H 28 .

[0026] The generated water retainer has a rigid benzene ring structure, which makes the water retainer in a stretched state in the cement paste. The R group makes the product flexible, just like a rope connecting short sticks. When the concrete is static, the water retainer molecules are stretched in the cement paste, isotropic, and the molecules are entangled with each other, making the concrete viscosity larger, which can effectively reduce bleeding and segregation. When the concrete is pumped, the water retainer molecules are sheared, and due to the rigid structure of the benzene ring, the molecular chain stretches in the shear direction, so that the water retainer molecules can reduce bleeding and segregation without affecting the plastic viscosity of the concrete. DETAILED DESCRIPTION

[0027] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0028] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0029] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0030] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0031] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0032] The embodiment of the present invention provides a water retaining agent for pumping concrete, the structural formula of which is:

[0033]

[0034] Among them, R is C4H8, C5H 10 、C6H 12 、C7H 14 、C8H 16 、C9H 18 , C 10 H 20 , C 12 H 24 or C 14 H 28 ; The value of n satisfies that the weight average molecular weight of the water-retaining agent is 1 million to 3 million, that is, by controlling the value of n, the weight average molecular weight of the water-retaining agent is 1 million to 3 million.

[0035] In a preferred embodiment of the present invention, the water retaining agent for pumping concrete is calculated by weight, and the raw materials for preparing the water retaining agent for pumping concrete include: 100 parts of intermediate, 50-200 parts of epichlorohydrin, 2-10 parts of NaOH solution and 10-50 parts of perchloric acid solution; the raw materials for preparing the intermediate include, by weight, 100 parts of methyl 2,5-dihydroxybenzoate and 150-450 parts of monomer; the monomer is an aliphatic monobasic acid substituted with a terminal amino group.

[0036] In a preferred embodiment of the present invention, the monomer includes one or more of 4-aminobutyric acid, 5-aminopentanoic acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 12-aminododecanoic acid and 14-aminotetradecanoic acid.

[0037] In a preferred embodiment of the present invention, the concentration of the NaOH solution is 30 wt %, and the concentration of the perchloric acid solution is 30 wt %.

[0038] The embodiment of the present invention also provides a method for preparing the water retaining agent for pumping concrete, comprising the following steps:

[0039] (1) methyl 2,5-dihydroxybenzoate, a monomer and a catalyst are stirred uniformly and heated for reaction. After the reaction is completed, the mixture is cooled to room temperature to obtain an intermediate;

[0040] (2) The intermediate obtained in step (1) is uniformly stirred with epichlorohydrin and a catalyst and heated for reaction, and then a NaOH solution and a perchloric acid solution are added dropwise. After the addition is completed, the mixture is kept warm and subjected to reduced pressure distillation to obtain the water retaining agent for pumping concrete.

[0041] In step (1) of the preferred embodiment of the present invention, the heating reaction temperature is 80-150° C. and the time is 1-8 hours.

[0042] In step (1) of the preferred embodiment of the present invention, the catalyst is one or more of dibutyltin dilaurate, dibutyltin oxide, tetrabutyl titanate and magnesium acetylacetonate, and the amount of the catalyst added is 2.5-17 parts by weight.

[0043] In step (2) of the preferred embodiment of the present invention, the heating reaction temperature is 60-90° C. and the time is 1-8 hours.

[0044] In step (2) of the preferred embodiment of the present invention, the catalyst is triethylbenzyl ammonium chloride, and the amount of the catalyst added is 0.8-3 parts by weight.

[0045] In step (2) of the preferred embodiment of the present invention, NaOH solution and perchloric acid solution are added dropwise at 50-80°C.

[0046] In step (2) of the preferred embodiment of the present invention, the NaOH solution is added dropwise for 1-5 hours, and the mixture is kept warm for 1-3 hours after the addition is complete. The perchloric acid solution is then added dropwise for 0.5-2 hours, and the mixture is kept warm for 1-2 hours after the addition is complete.

[0047] The reaction process in the preparation process of the water retaining agent for pumped concrete in the embodiment of the present invention is as follows:

[0048]

[0049] Where R is C4H8, C5H 10 、C6H 12 、C7H 14 、C8H 16 、C9H 18 , C 10 H 20 , C 12 H 24 or C 14 H 28 .

[0050] All raw materials used in the examples of the present invention are commercially available.

[0051] In the embodiments of the present invention, "room temperature" refers to "25±2°C".

[0052] In the embodiments of the present invention, "parts" represent "parts by weight" unless otherwise specified.

[0053] The technical solution of the present invention is further illustrated by the following embodiments.

[0054] Example 1

[0055] (1) Add 100 parts of methyl 2,5-dihydroxybenzoate, 150 parts of monomer (4-aminobutyric acid) and 2.5 parts of catalyst (dibutyltin dilaurate) into a three-necked flask equipped with a stirrer and a thermometer, stir evenly and heat to 80°C, react for 4 hours and then cool to room temperature to obtain an intermediate;

[0056] (2) 100 parts of the intermediate obtained in step (1), 50 parts of epichlorohydrin and 0.8 parts of triethylbenzyl ammonium chloride were added to a three-necked flask equipped with a stirrer and a thermometer, stirred evenly and heated to 60°C. After reacting for 3 hours, the temperature was adjusted to 50°C, and then 2 parts of 30wt% NaOH solution were added dropwise for 2 hours. After the addition was completed, the mixture was kept warm for 1 hour. Then 10 parts of 30wt% perchloric acid solution were added dropwise for 0.5 hours. After the addition was completed, the mixture was kept warm for 1 hour. Water and epichlorohydrin were removed by distillation under reduced pressure to obtain a water retaining agent for pumping concrete.

[0057] Example 2

[0058] (1) Add 100 parts of methyl 2,5-dihydroxybenzoate, 230 parts of monomer (10-aminodecanoic acid) and 7 parts of catalyst (dibutyltin oxide) into a three-necked flask equipped with a stirrer and a thermometer, stir evenly and heat to 110°C, react for 6 hours and then cool to room temperature to obtain an intermediate;

[0059] (2) 100 parts of the intermediate obtained in step (1), 100 parts of epichlorohydrin and 2.4 parts of triethylbenzyl ammonium chloride were added to a three-necked flask equipped with a stirrer and a thermometer, stirred evenly and heated to 80°C. After reacting for 6 hours, the temperature was adjusted to 70°C, and then 10 parts of a 30wt% NaOH solution were added dropwise for 3 hours. After the addition was completed, the mixture was kept warm for 3 hours. Then, 15 parts of a 30wt% perchloric acid solution were added dropwise for 1 hour. After the addition was completed, the mixture was kept warm for 1 hour. Water and epichlorohydrin were removed by distillation under reduced pressure to obtain a water retaining agent for pumping concrete.

[0060] Example 3

[0061] (1) Add 100 parts of methyl 2,5-dihydroxybenzoate, 300 parts of monomer (14-aminotetradecanoic acid) and 2.5 parts of catalyst (tetrabutyl titanate) into a three-necked flask equipped with a stirrer and a thermometer, stir evenly and heat to 130°C, react for 7 hours and then cool to room temperature to obtain an intermediate;

[0062] (2) 100 parts of the intermediate obtained in step (1), 150 parts of epichlorohydrin and 3 parts of triethylbenzyl ammonium chloride were added to a three-necked flask equipped with a stirrer and a thermometer, stirred evenly and heated to 90°C. After reacting for 12 hours, the temperature was adjusted to 80°C, and then 8 parts of 30wt% NaOH solution were added dropwise for 5 hours. After the addition was completed, the mixture was kept warm for 3 hours. Then, 50 parts of 30wt% perchloric acid solution were added dropwise for 2 hours. After the addition was completed, the mixture was kept warm for 2 hours. Water and epichlorohydrin were removed by vacuum distillation to obtain a water retaining agent for pumping concrete.

[0063] Example 4

[0064] (1) Add 100 parts of methyl 2,5-dihydroxybenzoate, 230 parts of monomer (6-aminocaproic acid) and 5 parts of catalyst (dibutyltin oxide) into a three-necked flask equipped with a stirrer and a thermometer, stir evenly and heat to 130°C, react for 6 hours and then cool to room temperature to obtain an intermediate;

[0065] (2) 100 parts of the intermediate obtained in step (1), 150 parts of epichlorohydrin and 2 parts of triethylbenzyl ammonium chloride were added to a three-necked flask equipped with a stirrer and a thermometer, stirred evenly and heated to 90°C. After reacting for 8 hours, the temperature was adjusted to 50°C, and then 10 parts of 30wt% NaOH solution were added dropwise for 2 hours. After the addition was completed, the mixture was kept warm for 1 hour. Then 40 parts of 30wt% perchloric acid solution were added dropwise for 1.5 hours. After the addition was completed, the mixture was kept warm for 2 hours. Water and epichlorohydrin were removed by distillation under reduced pressure to obtain a water retaining agent for pumping concrete.

[0066] Example 5

[0067] (1) Add 100 parts of methyl 2,5-dihydroxybenzoate, 450 parts of monomer (12-aminododecyl acid) and 17 parts of catalyst (magnesium acetylacetonate) into a three-necked flask equipped with a stirrer and a thermometer, stir evenly and heat to 150°C. After reacting for 1 hour, cool to room temperature to obtain an intermediate;

[0068] (2) 100 parts of the intermediate obtained in step (1), 200 parts of epichlorohydrin and 0.8 parts of triethylbenzyl ammonium chloride were added to a three-necked flask equipped with a stirrer and a thermometer, stirred evenly and heated to 90°C. After reacting for 1 hour, the temperature was adjusted to 80°C, and then 2 parts of 30wt% NaOH solution were added dropwise for 1 hour. After the addition was completed, the temperature was kept warm for 1 hour. Then 50 parts of 30wt% perchloric acid solution were added dropwise for 2 hours. After the addition was completed, the temperature was kept warm for 2 hours. Water and epichlorohydrin were removed by vacuum distillation to obtain a water retaining agent for pumping concrete.

[0069] Example 6

[0070] (1) Add 100 parts of methyl 2,5-dihydroxybenzoate, 150 parts of monomer (7-aminoheptanoic acid) and 2.5 parts of catalyst (tetrabutyl titanate) into a three-necked flask equipped with a stirrer and a thermometer, stir evenly and heat to 80°C, react for 8 hours and then cool to room temperature to obtain an intermediate;

[0071] (2) 100 parts of the intermediate obtained in step (1), 50 parts of epichlorohydrin and 3 parts of triethylbenzyl ammonium chloride were added to a three-necked flask equipped with a stirrer and a thermometer, stirred evenly and heated to 60°C. After reacting for 12 hours, the temperature was adjusted to 50°C, and then 10 parts of 30wt% NaOH solution were added dropwise for 5 hours. After the addition was completed, the mixture was kept warm for 3 hours. Then, 10 parts of 30wt% perchloric acid solution were added dropwise for 0.5 hours. After the addition was completed, the mixture was kept warm for 1 hour. Water and epichlorohydrin were removed by vacuum distillation to obtain a water retaining agent for pumping concrete.

[0072] Comparative Example 1

[0073] Cellulose (purchased from Shandong Meikai Chemical Co., Ltd.).

[0074] Comparative Example 2

[0075] (1) Add 100 parts of methyl 2,5-dihydroxybenzoate, 150 parts of monomer (16-aminohexadecanoic acid) and 2.5 parts of catalyst (dibutyltin dilaurate) into a three-necked flask equipped with a stirrer and a thermometer, stir evenly and heat to 80°C, react for 4 hours and then cool to room temperature to obtain an intermediate;

[0076] (2) 100 parts of the intermediate obtained in step (1), 50 parts of epichlorohydrin and 0.8 parts of triethylbenzyl ammonium chloride were added to a three-necked flask with a stirrer and a thermometer, stirred evenly and heated to 60°C. After reacting for 3 hours, the temperature was adjusted to 50°C, and then 2 parts of 30wt% NaOH solution were added dropwise for 2 hours. After the addition was completed, the temperature was kept warm for 1 hour. Then 10 parts of 30wt% perchloric acid solution were added dropwise for 0.5 hours. After the addition was completed, the temperature was kept warm for 1 hour. Water and epichlorohydrin were removed by vacuum distillation to obtain a water retaining agent for pumping concrete.

[0077] Performance Testing

[0078] The water retaining agent prepared in Examples 1-6, the cellulose in Comparative Example 1 and Comparative Example 2 were used to test the working performance of cement concrete, with the dosage of 0.5 / 10,000 (0.5 unit mass of water retaining agent per 10,000 unit mass of the mixture), wherein the initial expansion of the concrete was controlled to 580±5 mm, the concrete mix ratio was shown in Table 1, and the concrete performance test results were shown in Table 2. The water reducing agent was GK-3000 (Shijiazhuang Changan Yucai Building Materials Co., Ltd.).

[0079] Table 1 Concrete mix ratio (kg / m 3 )

[0080]

[0081] Table 1 5-10 For example, stone 5-10 Indicates stones with a particle size of 5-10mm.

[0082] Table 2 Concrete performance test results

[0083]

[0084] It can be seen from the data in Table 2 that when the expansion degree of concrete is similar, the anti-bleeding and segregation effect of Examples 1-6 is stronger, and the pouring time is significantly shorter, so that the plastic viscosity of the concrete is lower and the pumpability is better.

[0085] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A water retaining agent for pumping concrete, characterized in that: The structural formula is: ， Among them, R is C4H8, C5H 10 、C6H 12 、C7H 14 、C8H 16 、C9H 18 , C 10 H 20 , C 12 H 24 or C 14 H 28 ; The value of n satisfies that the weight average molecular weight of the water retaining agent is 1 million to 3 million; The raw materials for preparing the water retaining agent for pumping concrete include, by weight: 100 parts of intermediate, 50-200 parts of epichlorohydrin, 2-10 parts of NaOH solution and 10-50 parts of perchloric acid solution; The raw materials for preparing the intermediate include, by weight, 100 parts of methyl 2,5-dihydroxybenzoate and 150-450 parts of monomers; The monomers include one or more of 4-aminobutyric acid, 5-aminopentanoic acid, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 12-aminododecanoic acid and 14-aminotetradecanoic acid.

2. The water retaining agent for pumped concrete according to claim 1, characterized in that: The concentration of the NaOH solution is 30 wt %, and the concentration of the perchloric acid solution is 30 wt %.

3. A method for preparing a water retaining agent for pumping concrete according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) methyl 2,5-dihydroxybenzoate, a monomer and a catalyst are stirred uniformly and heated for reaction. After the reaction is completed, the temperature is cooled to room temperature to obtain an intermediate; (2) The intermediate obtained in step (1) is uniformly stirred with epichlorohydrin and a catalyst and heated for reaction, and then a NaOH solution and a perchloric acid solution are added dropwise. After the addition is completed, the mixture is kept warm and subjected to reduced pressure distillation to obtain the water retaining agent for pumping concrete.

4. The method for preparing a water retaining agent for pumped concrete according to claim 3, characterized in that: In step (1), the heating reaction temperature is 80-150° C. and the time is 1-8 hours.

5. The method for preparing a water retaining agent for pumped concrete according to claim 3, characterized in that: In step (1), the catalyst is one or more of dibutyltin dilaurate, dibutyltin oxide, tetrabutyl titanate and magnesium acetylacetonate, and the amount of the catalyst added is 2.5-17 parts by weight.

6. The method for preparing a water retaining agent for pumped concrete according to claim 3, characterized in that: In step (2), the heating reaction temperature is 60-90° C. and the time is 1-8 hours.

7. The method for preparing a water retaining agent for pumped concrete according to claim 3, characterized in that: In step (2), the catalyst is triethylbenzyl ammonium chloride, and the amount of the catalyst added is 0.8-3 parts by weight.

8. The method for preparing a water retaining agent for pumped concrete according to claim 3, characterized in that: In step (2), NaOH solution and perchloric acid solution are added dropwise at 50-80°C.

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