Anti-segregation agent and preparation method thereof

Abstract

The present invention relates to an anti-segregation agent and a preparation method thereof, the anti-segregation agent comprising, by weight: 30 to 50 parts of an early anti-segregation component; 45 to 70 parts of a late anti-segregation component; and water; the raw materials for preparing the late anti-segregation component include unsaturated acid, acrylamide and / or its derivatives, thickening functional monomers, oxidants, reducing agents and water; the raw materials for preparing the early anti-segregation component include guar gum, lauroyl chloride, alkaline solution, solvent and water. The present invention prepares the anti-segregation agent by compounding the early anti-segregation component and the late anti-segregation component, which can greatly prolong the action time of the anti-segregation agent, and the anti-segregation agent prepared by the present invention can be stably stored and has excellent action effect.

Description

Technical Field

[0001] The invention relates to the technical field of concrete admixtures, in particular to an anti-segregation agent and a preparation method thereof. Background Art

[0002] 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.

[0003] Anti-segregation agents are usually added to concrete to improve the flow properties of the concrete mixture. Anti-segregation agents adjust the fluidity and viscosity of the concrete mixture and rescue segregated concrete, thereby improving the quality and stability of concrete.

[0004] Anti-segregation agent needs to be added during premixing at the commercial concrete mixing station. In the actual application process of the project, affected by factors such as temperature, transportation distance, and ground material quality, the commercial concrete will be very different from its initial condition when it arrives at the construction site. Problems such as concrete segregation and water seepage still exist, and the strength of the concrete will also be affected. Summary of the invention

[0005] 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.

[0006] To achieve the above object, the present invention provides a technical solution:

[0007] An anti-segregation agent, in parts by weight, comprising:

[0008] 30-50 parts of anti-segregation component in the early stage;

[0009] 45-70 parts of late stage anti-segregation component; and

[0010] water;

[0011] 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;

[0012] The raw materials for preparing the preliminary anti-segregation component include guar gum, lauroyl chloride, alkaline solution, solvent and water.

[0013] Preferably, in parts by weight, the raw materials for preparing the late-stage anti-segregation component include:

[0014]

[0015] Preferably, the raw materials for preparing the thickening functional monomer include: 2-(hydroxy-p-toluenemethyl)-methyl acrylate and oxalic acid.

[0016] Preferably, the acrylamide and / or its derivatives include at least one of acrylamide, 2-acrylamido-2-phenylethanesulfonic acid, N-isobutylacrylamide and N-hydroxyacrylamide.

[0017] Preferably, the unsaturated acid monomer includes at least one of acrylic acid and methacrylic acid.

[0018] Preferably, the oxidizing agent comprises at least one of barium persulfate and ammonium persulfate.

[0019] Preferably, the reducing agent comprises sodium hypophosphite.

[0020] The present invention also provides a method for preparing the anti-segregation agent, comprising the steps of:

[0021] The anti-segregation agent is obtained by compounding the early anti-segregation component, the late anti-segregation component and water.

[0022] Preferably, the preparation steps of the late anti-segregation component include:

[0023] The unsaturated acid, the acrylamide and / or its derivatives, the thickening functional monomer and water are mixed to prepare a base material;

[0024] Adjust the pH of the base material to 8-9.5, add liquid A and liquid B dropwise to the base material, and keep the temperature for reaction for 2-5 hours after the addition is completed, so as to obtain the late-stage anti-segregation component;

[0025] Wherein, the liquid A includes the reducing agent and water;

[0026] The B liquid includes the oxidant and water.

[0027] Preferably, the preparation steps of the early anti-segregation component include:

[0028] The guar gum is dissolved in water, and the pH value is adjusted to 7-8 using an alkali to obtain a guar gum aqueous solution;

[0029] lauroyl chloride is dropped into the guar gum aqueous solution to react and obtain a mixed solution;

[0030] Pour the solvent into the mixture, terminate the reaction, filter, wash, filter and dry to obtain the early anti-segregation component.

[0031] Beneficial effects of the present invention:

[0032] The anti-segregation agent prepared by the 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.

[0033] The late 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, greatly improve the action time and stability of the anti-segregation agent, and the late anti-segregation agent inhibits the segregation phenomenon of concrete in the later stage.

[0034] 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.

[0035] The anti-segregation agent prepared by the invention has safe process, stable storage, easy control of conditions and is easy for industrial production. DETAILED DESCRIPTION

[0036] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0037] 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.

[0038] An anti-segregation agent, in parts by weight, comprising:

[0039] 30-50 parts of anti-segregation component in the early stage;

[0040] 45-70 parts of late stage anti-segregation component; and

[0041] water;

[0042] 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;

[0043] The raw materials for preparing the preliminary anti-segregation component include guar gum, lauroyl chloride, alkaline solution, solvent and water.

[0044] In one embodiment, the raw materials for preparing the anti-segregation component in the early stage include, by weight:

[0045]

[0046]

[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] Add 2-(hydroxy-p-toluenemethyl)-methyl acrylate, oxalic acid, a catalyst and an inhibitor into a reactor equipped with a condensing device, 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.

[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 includes 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]

[0055] 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.

[0056] In one embodiment, the unsaturated acid monomer includes at least one of acrylic acid and methacrylic acid.

[0057] In one embodiment, the oxidant includes at least one of barium persulfate and ammonium persulfate.

[0058] In one embodiment, the reducing agent comprises sodium hypophosphite.

[0059] The present invention also provides a method for preparing the anti-segregation agent, comprising the steps of:

[0060] The anti-segregation agent is obtained by compounding the early anti-segregation component, the late anti-segregation component and water.

[0061] In one embodiment, the preparation steps of the late anti-segregation component include:

[0062] The unsaturated acid, the acrylamide and / or its derivatives, the thickening functional monomer and water are mixed to prepare a base material;

[0063] Adjust the pH of the base material to 8, add solution A and solution B dropwise to the base material, and keep the temperature for reaction for 2 to 5 hours after the addition is completed, so as to obtain the late-stage anti-segregation component;

[0064] Wherein, the liquid A includes the reducing agent and water;

[0065] The B liquid includes the oxidant and water.

[0066] In one embodiment, the steps of preparing the early anti-segregation component include:

[0067] The guar gum is dissolved in water, and the pH value is adjusted to 7-8 using an alkali to obtain a guar gum aqueous solution;

[0068] lauroyl chloride is dropped into the guar gum aqueous solution to react and obtain a mixed solution;

[0069] Pour the solvent into the mixture, terminate the reaction, filter, wash, filter and dry to obtain the early anti-segregation component.

[0070] The mass ratio of guar gum: water: solvent: lauroyl chloride is 1: (55-65): (60-70): (2-3).

[0071] Embodiment and comparative example:

[0072] 1. Preparation of preliminary anti-segregation components

[0073] dissolving guar gum in water at 25° C. and adjusting the pH value to 7 using an alkali to obtain a guar gum aqueous solution;

[0074] The initial reaction temperature was 25°C, and lauroyl chloride was slowly added dropwise to the guar gum aqueous solution for 1.5 h.

[0075] Pour into a solvent (ethanol) to terminate the reaction and filter. Dry the product at 25°C for 24 hours, wash with ethanol, filter, and dry to obtain the early anti-segregation component.

[0076] Among them, the mass ratio of guar gum: water: ethanol: lauroyl chloride is 1:60:65:2.4.

[0077] 2. Preparation of thickening functional monomer

[0078] The product is prepared from 2-(hydroxy-p-toluenemethyl)-methyl acrylate and oxalic acid.

[0079] The specific steps are as follows:

[0080] Add 2-(hydroxy-p-toluenemethyl)-methyl acrylate, oxalic acid, catalyst (concentrated sulfuric acid) and inhibitor (p-hydroxyanisole) into a reactor equipped with a condensing device, 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.

[0081] The mass ratio of 2-(hydroxy-p-toluenemethyl)-methyl acrylate: oxalic acid: catalyst: inhibitor = 100:50:1:1.

[0082] The structural formula of the thickening functional monomer is as follows:

[0083]

[0084] 3. Preparation of late anti-segregation components

[0085] Preparation steps:

[0086] Mixing unsaturated acid, acrylamide and / or its derivatives, the thickening functional monomer prepared in step 2 and water to prepare a base material;

[0087] The initial reaction temperature is 60-75°C, the pH of the base material is adjusted to 8-9.5, and liquid A and liquid B are added dropwise to the base material for 1.5-3 hours. After the addition is completed, the reaction is kept warm for 2-5 hours to obtain the late-stage anti-segregation component;

[0088] Wherein, the liquid A includes the reducing agent and water;

[0089] The B liquid includes the oxidant and water.

[0090] The raw materials, mass fractions and reaction conditions for preparing the late-stage anti-segregation components in each embodiment are shown in Table 1.

[0091] Table 1 Preparation raw materials and mass fractions of the late anti-segregation components in each embodiment

[0092]

[0093] 4. Preparation of anti-segregation agent

[0094] The early anti-segregation component prepared in step 1, the late anti-segregation component prepared in step 3 and water are compounded 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.

[0095] Table 2 The quality of the pre-anti-segregation component and the post-anti-segregation component in Examples 1 to 4

[0096]

[0097] Comparative Example 1

[0098] The difference between Comparative Example 1 and Example 1 is that no thickening functional monomer is added when preparing the later anti-segregation component.

[0099] Comparative Example 2

[0100] The difference between Comparative Example 1 and Example 1 is that when preparing the anti-segregation agent, no preliminary anti-segregation component is added.

[0101] In order to verify the effects of the above embodiments and comparative examples, C30 concrete mix ratio was used:

[0102] Cement 360kg / m 3 , sand 840kg / m 3 、Stone (1) 805kg / m 3 、Stone (2) 205kg / m 3 , water 170kg / m 3 , try mixing 15L of concrete.

[0103] First, adjust the amount of admixture until the concrete segregates, keep the same mix ratio, add an appropriate amount of anti-segregation agent after mixing, and then stir for 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.

[0104] Table 3 Concrete performance test results

[0105]

[0106] Table 4 Concrete compressive strength test results

[0107]

[0108] It can be seen from Tables 3 and 4 that under the conditions of equal dosage of anti-segregation agent, Comparative Example 1, which does not introduce thickening functional monomers, has poor anti-segregation retention ability (the non-segregated state cannot be maintained at the beginning of 1 hour, and severe segregation occurs after 3 hours); Comparative Example 2, which does not compound the early anti-segregation component, has poor initial anti-segregation effect (the whole is in a state of slight segregation).

[0109] Therefore, the anti-segregation agents prepared in Examples 1 to 4 of the present invention have strong anti-segregation retention ability and high strength.

[0110] It should be noted that the specific parameters or some reagents in the above embodiments are specific embodiments or preferred embodiments of the present invention, rather than limiting the present invention; those skilled in the art can make adaptive adjustments within the scope of the present invention.

Claims

1. An anti-segregation agent, It is characterized in that In parts by weight, the anti-segregation agent comprises: 30-50 parts of anti-segregation component in the early stage; 45-70 parts of late stage anti-segregation component; and water; 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; The raw materials for preparing the anti-segregation component in the early stage include guar gum, lauroyl chloride, alkaline solution, ethanol and water; The mass ratio of guar gum: water: ethanol: lauroyl chloride is 1: (55-65): (60-70): (2-3); The raw materials for preparing the thickening functional monomer include: 2-(hydroxy-p-toluenemethyl)-methyl acrylate, oxalic acid, a catalyst and an inhibitor; The mass ratio of 2-(hydroxy-p-toluenemethyl)-methyl acrylate: oxalic acid: catalyst: inhibitor = 100: (45-80): (0.5-2): (0.5-1.5); The catalyst includes at least one of concentrated sulfuric acid, heteropoly acid, stannous oxide and dibutyltin oxide; The polymerization inhibitor includes at least one of p-hydroxyanisole, hydroquinone, p-tert-butylcatechol and phenothiazine.

2. The anti-segregation agent according to claim 1, It is characterized in that In parts by weight, the raw materials for preparing the late-stage anti-segregation component include: 200-400 parts of unsaturated acid; 1000-1400 parts of acrylamide and / or its derivatives; 1 to 5 parts of thickening functional monomer; 20-40 parts of oxidant; 2 to 14 parts of reducing agent; and water.

3. The anti-segregation agent according to claim 1, It is characterized in that The acrylamide and / or its derivatives include at least one of acrylamide, 2-acrylamido-2-phenylethanesulfonic acid, N-isobutylacrylamide and N-hydroxyacrylamide.

4. The anti-segregation agent according to claim 1, It is characterized in that The unsaturated acid monomer includes at least one of acrylic acid and methacrylic acid.

5. The anti-segregation agent according to claim 1, It is characterized in that The oxidant includes at least one of barium persulfate and ammonium persulfate.

6. The anti-segregation agent according to claim 1, It is characterized in that The reducing agent includes sodium hypophosphite.

7. A method for preparing the anti-segregation agent according to any one of claims 1 to 6, It is characterized in that Includes steps: The anti-segregation agent is obtained by compounding the early anti-segregation component, the late anti-segregation component and water.

8. The method for preparing the anti-segregation agent according to claim 7, It is characterized in that The preparation steps of the late anti-segregation component include: The unsaturated acid, the acrylamide and / or its derivatives, the thickening functional monomer and water are mixed to prepare a base material; 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 temperature for reaction for 2-5 hours after the addition is completed, so as to obtain the late-stage anti-segregation component; Wherein, the liquid A includes the reducing agent and water; The B liquid includes the oxidant and water.

9. The method for preparing the anti-segregation agent according to claim 7, It is characterized in that The preparation steps of the early stage anti-segregation component include: The guar gum is dissolved in water, and the pH value is adjusted to 7-8 using an alkaline solution to obtain a guar gum aqueous solution; lauroyl chloride is dropped into the guar gum aqueous solution to react and obtain a mixed solution; Pour ethanol into the mixture, terminate the reaction, filter, wash, filter and dry to obtain the early anti-segregation component.

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