Anti-isolation agents and methods of preparation.

Abstract

Invention details;

Description

Anti-segregation agent and preparation method thereof

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application with application number 202311741286.4 filed with the Chinese Patent Office on December 18, 2023, entitled "Anti-segregation agent and its preparation method", the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present invention relates to the technical field of concrete admixtures, in particular to an anti-segregation agent and a preparation method thereof. Background Art

[0004] During the concrete mixing process, due to material fluctuations, human errors and other reasons, concrete materials are prone to segregation, resulting in the separation of components of the concrete mixture, thus affecting the quality and performance of the concrete.

[0005] Anti-segregation agents are usually added to concrete to improve the flow properties of the concrete mixture. Anti-segregation agents regulate the fluidity and viscosity of the concrete mixture, rescue segregated concrete, and thus improve the quality and stability of concrete.

[0006] Anti-segregation agent needs to be added during pre-mixing at the commercial concrete mixing station. In the actual application process of the project, due to the influence of factors such as temperature, transportation distance, and quality of ground materials, the commercial concrete will be very different from its initial condition when it arrives at the construction site. Problems of concrete segregation and water seepage still exist, and the strength of the concrete will also be affected.

[0007] Summary of the Invention

[0008] Based on this, it is necessary to provide an anti-segregation agent that can be stably stored and has excellent effect and a preparation method thereof.

[0009] To achieve the above object, the present invention provides a technical solution:

[0010] An anti-segregation agent, in parts by weight, comprising:

[0011] 30-50 parts of anti-segregation component in the early stage;

[0012] 45-70 parts of late stage anti-segregation component; and

[0013] water;

[0014] The raw materials for preparing the late-stage anti-segregation component include unsaturated acid, acrylamide and / or its derivatives, thickening functional monomers, oxidizing agent, reducing agent and water;

[0015] The raw materials for preparing the early stage anti-segregation component include guar gum, lauroyl chloride, alkaline solution, solvent and water.

[0016] Preferably, the raw materials for preparing the late-stage anti-segregation component include, by weight:

[0017] Preferably, the raw materials for preparing the thickening functional monomer include: 2-(hydroxy-p-toluenemethyl)-methyl acrylate and oxalic acid.

[0018] Preferably, the acrylamide and / or its derivatives include at least one of acrylamide, 2-acrylamido-2-phenylethanesulfonic acid, N-isobutylacrylamide and N-hydroxyacrylamide.

[0019] Preferably, the unsaturated acid monomer includes at least one of acrylic acid and methacrylic acid.

[0020] Preferably, the oxidizing agent comprises at least one of barium persulfate and ammonium persulfate.

[0021] Preferably, the reducing agent comprises sodium hypophosphite.

[0022] The present invention also provides a method for preparing the above-mentioned anti-segregation agent, comprising the steps of:

[0023] The anti-segregation agent is obtained by compounding the early anti-segregation component, the late anti-segregation component and water.

[0024] Preferably, the preparation steps of the late anti-segregation component include:

[0025] Mixing the unsaturated acid, the acrylamide and / or its derivatives, the thickening functional monomer and water to prepare a base material;

[0026] Adjust the pH of the base material to 8-9.5, add solution A and solution B dropwise to the base material, and keep the mixture warm for 2-5 hours to obtain the late-stage anti-segregation component;

[0027] Wherein, the liquid A comprises the reducing agent and water;

[0028] The B solution includes the oxidant and water.

[0029] Preferably, the steps of preparing the anti-segregation component in the early stage include:

[0030] Dissolving guar gum in water and adjusting the pH value to 7-8 with alkali to obtain a guar gum aqueous solution;

[0031] lauroyl chloride is dropped into the guar gum aqueous solution to react and obtain a mixed solution;

[0032] Pour the solvent into the mixture, terminate the reaction, filter, wash, filter and dry to obtain the early anti-segregation component.

[0033] Beneficial effects of the present invention:

[0034] The anti-segregation agent prepared by the present invention introduces guar gum modified with lauroyl chloride as an early anti-segregation component. The guar gum modified with lauroyl chloride has good thickening ability and can reduce the occurrence of concrete segregation in the early stage.

[0035] The late-stage anti-segregation component of the anti-segregation agent prepared by the present invention introduces a thickening functional monomer prepared from 2-(hydroxy-p-tolumethyl)-methyl acrylate and oxalic acid to form a cross-linked structure, which can significantly improve the workability of concrete and greatly increase the action time and stability of the anti-segregation agent. The late-stage anti-segregation agent suppresses the segregation phenomenon of concrete in the late stage.

[0036] The present invention adopts the early anti-segregation component and the late anti-segregation component to prepare the anti-segregation agent, which can greatly prolong the action time of the anti-segregation agent.

[0037] The anti-segregation agent prepared by the invention has the advantages of safe process, stable storage, easy control of conditions and easy industrial production. DETAILED DESCRIPTION

[0038] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below with reference to specific embodiments.

[0039] In the examples, the test methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are all commercially available unless otherwise specified.

[0040] An anti-segregation agent, in parts by weight, comprising:

[0041] 30-50 parts of anti-segregation component in the early stage;

[0042] 45-70 parts of late stage anti-segregation component; and

[0043] water;

[0044] The raw materials for preparing the late-stage anti-segregation component include unsaturated acid, acrylamide and / or its derivatives, thickening functional monomers, oxidizing agent, reducing agent and water;

[0045] The raw materials for preparing the early stage anti-segregation component include guar gum, lauroyl chloride, alkaline solution, solvent and water.

[0046] In one embodiment, the raw materials for preparing the anti-segregation component in the early stage include, by weight:

[0047] In one embodiment, the raw materials for preparing the thickening functional monomer include: 2-(hydroxy-p-toluenemethyl)-methyl acrylate and oxalic acid.

[0048] The specific preparation steps of the thickening monomer are as follows

[0049] 2-(hydroxy-p-toluenemethyl)-methyl acrylate, oxalic acid, a catalyst and a polymerization inhibitor are added to a reactor equipped with a condensing device. Under nitrogen protection, the reaction is carried out at a constant temperature of 100-120°C for 4-8 hours. After the reaction is completed, the temperature is lowered to 40°C to obtain a thickening functional monomer.

[0050] The mass ratio of 2-(hydroxy-p-toluenemethyl)-methyl acrylate: oxalic acid: catalyst: polymerization inhibitor is 100: (45-80): (0.5-2): (0.5-1.5).

[0051] The catalyst comprises at least one of concentrated sulfuric acid, heteropoly acid, stannous oxide and dibutyltin oxide;

[0052] The polymerization inhibitor includes at least one of p-hydroxyanisole, hydroquinone, p-tert-butylcatechol and phenothiazine;

[0053] The structural formula of the thickening functional monomer is as follows:

[0054] In one embodiment, the acrylamide and / or its derivatives include at least one of acrylamide, 2-acrylamido-2-phenylethanesulfonic acid, N-isobutylacrylamide and N-hydroxyacrylamide.

[0055] In one embodiment, the unsaturated acid monomer includes at least one of acrylic acid and methacrylic acid.

[0056] In one embodiment, the oxidizing agent includes at least one of barium persulfate and ammonium persulfate.

[0057] In one embodiment, the reducing agent comprises sodium hypophosphite.

[0058] The present invention also provides a method for preparing the above-mentioned anti-segregation agent, comprising the steps of:

[0059] The anti-segregation agent is obtained by compounding the early anti-segregation component, the late anti-segregation component and water.

[0060] In one embodiment, the preparation steps of the late anti-segregation component include:

[0061] Mixing the unsaturated acid, the acrylamide and / or its derivatives, the thickening functional monomer and water to prepare a base material;

[0062] Adjust the pH of the base material to 8, add solution A and solution B dropwise to the base material, and keep the mixture warm for 2 to 5 hours after the addition is complete to obtain the late-stage anti-segregation component;

[0063] Wherein, the liquid A comprises the reducing agent and water;

[0064] The B solution includes the oxidant and water.

[0065] In one embodiment, the steps of preparing the anti-segregation component in the early stage include:

[0066] Dissolving guar gum in water and adjusting the pH value to 7-8 with alkali to obtain a guar gum aqueous solution;

[0067] lauroyl chloride is dropped into the guar gum aqueous solution to react and obtain a mixed solution;

[0068] Pour the solvent into the mixture, terminate the reaction, filter, wash, filter and dry to obtain the early anti-segregation component.

[0069] The mass ratio of guar gum: water: solvent: lauroyl chloride is 1: (55-65): (60-70): (2-3).

[0070] Examples and Comparative Examples:

[0071] 1. Preparation of early anti-segregation components

[0072] dissolving guar gum in water at 25° C. and adjusting the pH value to 7 with alkali to obtain a guar gum aqueous solution;

[0073] The initial reaction temperature was 25°C, and lauroyl chloride was slowly added dropwise to the guar gum aqueous solution for 1.5 h.

[0074] The mixture was poured into a solvent (ethanol) to terminate the reaction and filtered. The product was dried at 25° C. for 24 h, washed with ethanol, filtered, and dried to obtain the early anti-segregation component.

[0075] The mass ratio of guar gum: water: ethanol: lauroyl chloride is 1:60:65:2.4.

[0076] 2. Preparation of thickening functional monomer

[0077] The product is prepared from 2-(hydroxy-p-toluenemethyl)-methyl acrylate and oxalic acid.

[0078] The specific steps are as follows:

[0079] Add 2-(hydroxy-p-toluenemethyl)-methyl acrylate, oxalic acid, catalyst (concentrated sulfuric acid) and polymerization inhibitor (p-hydroxyanisole) into a reactor equipped with a condenser, and react at a constant temperature of 100-120°C for 4-8 hours under nitrogen protection. After the reaction, cool to 40°C to obtain a thickening functional monomer.

[0080] The mass ratio of 2-(hydroxy-p-toluenemethyl)-methyl acrylate: oxalic acid: catalyst: polymerization inhibitor = 100:50:1:1.

[0081] The structural formula of the thickening functional monomer is as follows:

[0082] 3. Preparation of late anti-segregation components

[0083] Preparation steps:

[0084] Mixing unsaturated acid, acrylamide and / or its derivatives, the thickening functional monomer prepared in step 2, and water to prepare a base material;

[0085] The initial reaction temperature is 60-75°C, the pH of the base material is adjusted to 8-9.5, and solution A and solution B are added dropwise to the base material for 1.5-3 hours. After the addition is completed, the temperature is kept to react for 2-5 hours to obtain the late-stage anti-segregation component;

[0086] Wherein, the liquid A comprises the reducing agent and water;

[0087] The B solution includes the oxidant and water.

[0088] The raw materials, mass fractions, and reaction conditions for preparing the late-stage anti-segregation component in each embodiment are shown in Table 1.

[0089] Table 1 Preparation of raw materials and mass fractions of the late anti-segregation components in each embodiment

[0090] 4. Preparation of anti-segregation agent

[0091] The early anti-segregation component prepared in step 1, the late anti-segregation component prepared in step 3 and water were mixed to prepare an anti-segregation agent with a mass concentration of 15 wt%. The mass ratio of the early anti-segregation component to the late anti-segregation component in Examples 1 to 4 is shown in Table 2.

[0092] Table 2 Mass of the pre-anti-segregation component and the post-anti-segregation component in Examples 1 to 4

[0093] Comparative Example 1

[0094] The difference between Comparative Example 1 and Example 1 is that no thickening functional monomer is added when preparing the later anti-segregation component.

[0095] Comparative Example 2

[0096] The difference between Comparative Example 1 and Example 1 is that no pre-segregation component is added when preparing the anti-segregation agent.

[0097] In order to verify the effects of the above embodiments and comparative examples, C30 concrete mix ratio was used:

[0098] Cement 360kg / m 3 , sand 840kg / m 3 、Stone (1) 805kg / m 3 Stone (2) 205kg / m 3 , water 170kg / m 3 , trial mix 15L of concrete.

[0099] First, adjust the amount of admixture until the concrete segregates, keeping the same mix ratio. After mixing, add an appropriate amount of anti-segregation agent and stir for another 30 seconds. The concrete performance test results are shown in Table 3, and the experimental results such as the concrete compressive strength test results are shown in Table 4.

[0100] Table 3 Concrete performance test results

[0101] Table 5 Concrete compressive strength test results

[0102] It can be seen from Tables 3 and 4 that under the conditions of the anti-segregation agent dosage, the comparative example 1 in which the thickening functional monomer is not introduced has a poor anti-segregation retention ability (the non-segregated state can no longer be maintained after 1 hour, and severe segregation occurs after 3 hours); the comparative example 2 in which the early anti-segregation component is not compounded has a poor initial anti-segregation effect (the whole is in a slightly segregated state).

[0103] Therefore, the anti-segregation agents prepared in Examples 1 to 4 of the present invention have strong anti-segregation retention ability and high strength.

[0104] It should be noted that the specific parameters or some reagents in the above embodiments are specific embodiments or preferred embodiments under the concept of the present invention, and are not intended to limit the present invention; those skilled in the art can make adaptive adjustments within the concept and protection scope of the present invention.

Claims

DEPCT671. Anti-separation agent characterized by the following components: 30-50 parts by weight of the first anti-separation component; 45-70 parts by weight of the second anti-separation component; and water; where the raw materials for the preparation of the second anti-separation component consist of unsaturated acids, acrylamide and / or its derivatives, functional monomers, thickeners, oxidizing agents, reducing agents, and water; and the raw materials for the preparation of the first anti-separation component. The first component consists of guar gum, lauryl chloride, alkali solution, solvent, and water.

2. The anti-separation agent of claim 1, which is characterized by the raw materials for the preparation of the second anti-separation component, consists of: 200-400 parts by weight of unsaturated acids; 1000-1400 parts by weight of acrylamide and / or its derivatives; 1-5 parts by weight of thickening functional monomers; 20-40 parts by weight of oxidizing agents; 2-14 parts by weight of reducing agents; and water. 3.The anti-disintegration agent of claim 1, characterized by the raw material for the preparation of functional monomers, is composed of methyl 2-(hydroxy-p-toluene methyl)-acrylate and oxalic acid.

4. The anti-disintegration agent of claim 1, characterized by the selection of acrylamide and / or its derivatives from a group consisting of acrylamide, 2-acrylamido-2-phenyl-ethenesulfonic acid, N-isobutyl acrylamide, N-hydroxyacrylamide and combinations of such substances.5 6. The anti-dissociation agent of claim 1, characterized by the selection of an unsaturated acid from a group comprising acrylic acid, methacrylic acid, and mixtures thereof.

7. The anti-dissociation agent of claim 1, characterized by the selection of an oxidizing agent from a group comprising barium persulfate, ammonium persulfate, and mixtures thereof.

8. The anti-dissociation agent of claim 1, characterized by the selection of a reducing agent, sodium hypophosphite.The method for preparing the anti-separation agent under any of the claims 1 through 7 is characterized by the following assembly procedure: the combination of the first anti-separation component, the second anti-separation component, and water to obtain the anti-separation agent.

9. The method of claim 8 is characterized by the following procedure: the second anti-separation component is prepared by the following steps: mixing unsaturated acids, acrylamide and / or their derivatives and functional monomers thickened in water to prepare the substrate; and adjusting the substrate to a pH of 8-9.5, adding liquids A and B drop by drop to the substrate followed by a reaction for 2-5 hours to obtain the second anti-separation component; where liquid A is composed of the reducing agent and water; and liquid B is composed of the oxidizing agent and water.10.The method of claim 8 is characterized by the first anti-dissociation component being prepared by the following steps: dissolving guar gum in water followed by adjusting to pH 7-8 with an alkali solution to obtain an aqueous guar gum solution; adding drop by drop of lauryl chloride to the aqueous guar gum solution for the reaction to obtain a mixture; and adding a solvent to the mixture followed by filtration, washing, vacuum filtration, and drying to obtain the first anti-dissociation component.