Ester polycarboxylic acid water reducing agent and preparation method thereof
The preparation of ester-based polycarboxylate superplasticizers by a one-step synthesis method solves the problems of cumbersome synthesis steps and poor adaptability of traditional ester-based polycarboxylate superplasticizers. It achieves excellent water-reducing and slump-retaining properties, adapts to different concrete raw materials, simplifies the production process, and reduces costs.
Patent Information
- Application Number
- CN202211739303.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-30
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2042-12-30
AI Technical Summary
Traditional ester-based polycarboxylate superplasticizers have complicated synthesis steps, high process control requirements, and difficult product quality control. They also have poor adaptability to different concrete raw materials, resulting in problems such as poor concrete cohesion, poor encapsulation, slow flow rate, segregation, and bleeding.
A one-step synthesis method was used to prepare ester-based polycarboxylate superplasticizers. A redox initiation system was used to carry out the reaction at room temperature, which simplified the process and improved the solubility of the raw materials. Polyethylene glycol methacrylate, unsaturated monomers, initiators, reducing agents and chain transfer agents were used as raw materials, and the superplasticizers were prepared by dropwise liquid contact reaction.
It achieves excellent water-reducing and slump-retaining properties of ester-based polycarboxylate superplasticizers, adapts to different concrete raw materials, solves concrete problems caused by material fluctuations, and has a simple process that can be mass-produced.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of concrete admixtures, in particular to an ester polycarboxylate superplasticizer and a preparation method thereof. BACKGROUND
[0002] The polycarboxylate superplasticizer is widely used in commercial concrete mixing station and key engineering projects such as bridges, tunnels, highways, ports and water conservancy. In recent years, with the rapid development of China's economic construction and the huge investment of the state in infrastructure construction, the production and application of polycarboxylate superplasticizers have broad prospects. With the increasing scarcity of high-quality sand and other resource materials, how to use different low-quality raw materials to mix high-performance concrete is the top priority in the research of concrete admixtures.
[0003] The synthesis of traditional ester polycarboxylate superplasticizers consists of two steps: the first step is to esterify MPEG monomer (polyethylene glycol monomethyl ether) with methacrylate to form a double-bond monomer; the second step is to free-radically polymerize the monomer synthesized by esterification with acrylic acid or methacrylic acid to form an ester polycarboxylate superplasticizer. The process synthesis of this superplasticizer is complicated, the process control requirements are high, and the product quality is difficult to control, which seriously limits the popularization and application of this type of product. SUMMARY
[0004] To solve the technical problems of poor adaptability of conventional ester polycarboxylate superplasticizers to different concrete raw materials, complicated synthesis steps and complex process in the prior art, one of the purposes of the present application is to provide an ester polycarboxylate superplasticizer which not only has excellent water-reducing performance and slump retention performance, but also has good adaptability to different concrete raw materials, and can effectively solve the problems of poor cohesiveness, poor encapsulation, slow flow rate, segregation and bleeding of concrete caused by material fluctuations and extensive use of inferior materials.
[0005] The second purpose of the present application is to provide a preparation method of an ester polycarboxylate superplasticizer, which adopts one-step synthesis method, can effectively shorten the synthesis time, has simple process, does not require strict reaction conditions and equipment, saves production cost, and can be used for large-scale production.
[0006] The third purpose of the present application is to provide an ester polycarboxylate superplasticizer prepared by the above preparation method.
[0007] To achieve one of the above purposes, the present application adopts the following technical solutions:
[0008] An ester polycarboxylate superplasticizer, by weight, comprises:
[0009] 100 parts of polyethylene glycol methacrylate, 20-30 parts of unsaturated monomer, 0.7-2 parts of initiator, 0.1-0.4 parts of reducing agent, 1-2 parts of chain transfer agent, 4-6 parts of sodium hydroxide and 180-200 parts of water.
[0010] In some preferred embodiments of the present application, the polyethylene glycol methacrylate is prepared by ethoxylation ring opening. The monomer prepared by this method has high purity and high double bond activity.
[0011] In some preferred embodiments of the present application, the number average molecular weight of the polyethylene glycol methacrylate is 500-2000.
[0012] In some preferred embodiments of the present application, the number average molecular weight of the polyethylene glycol methacrylate is one or more of 600, 1000 and 2000.
[0013] In some preferred embodiments of the present application, the polyethylene glycol methacrylate is a mixture of number average molecular weights of 600, 1000 and 2000 in equal mass proportions.
[0014] In some preferred embodiments of the present application, the unsaturated monomer is selected from one or two of acrylic acid, 2-acrylamide 2-methylpropane sulfonic acid, sodium methacryl sulfonate and 2-hydroxyethyl methacrylate phosphate ester; and / or
[0015] The initiator is ammonium persulfate; and / or
[0016] The reducing agent is sodium formaldehyde sulfoxylate and / or Bruggolite E51; and / or
[0017] The chain transfer agent is one or two of 3-mercaptopropionic acid, mercaptoethanol and mercaptoacetic acid.
[0018] To achieve the above-mentioned purpose two, the present application adopts the following technical solutions:
[0019] A preparation method of an ester polycarboxylic acid water reducing agent, comprising the following steps:
[0020] S1. Divide the polyethylene glycol methacrylate into two parts, mix the first part of the polyethylene glycol methacrylate with water to obtain a 1# dropping solution;
[0021] S2. Mix the reducing agent, the chain transfer agent and water to obtain a 2# dropping solution;
[0022] S3. Mix the unsaturated monomer with water to obtain a 3# dropping solution;
[0023] S4. Mix the second part of the polyethylene glycol methacrylate with water, add the initiator, and simultaneously add the 1# dropping solution, the 2# dropping solution and the 3# dropping solution for contact reaction, then add sodium hydroxide-water solution after the reaction, to obtain the water reducing agent.
[0024] The preparation method adopts a redox initiation system, compared with a conventional thermal decomposition initiation, can shorten the induction period, improve the polymerization rate, and thus can reduce the polymerization temperature, and even can polymerize at room temperature.
[0025] According to the present application, the purpose of adding water for mixing in each step of the preparation method is to dissolve raw materials, and water can be added according to actual conditions, which is not limited in the present application.
[0026] According to the present application, the mass ratio of the first part of polyethylene glycol methacrylate to the second part of polyethylene glycol methacrylate in the preparation method is (7-9):(1-3).
[0027] In some preferred embodiments of the present application, the ester polycarboxylic acid water reducer is prepared from raw materials including the following weight parts:
[0028] The polyethylene glycol methacrylate is 100 parts, the unsaturated monomer is 20-30 parts, the initiator is 0.7-2 parts, the reducing agent is 0.1-0.4 parts, the chain transfer agent is 1-2 parts, sodium hydroxide is 4-6 parts, and water is 180-200 parts.
[0029] In some preferred embodiments of the present application, the polyethylene glycol methacrylate is obtained by ethoxylation ring opening.
[0030] In some preferred embodiments of the present application, the number average molecular weight of the polyethylene glycol methacrylate is 500-2000.
[0031] In some preferred embodiments of the present application, the number average molecular weight of the polyethylene glycol methacrylate is one or more of 600, 1000 and 2000.
[0032] In some preferred embodiments of the present application, the polyethylene glycol methacrylate is a mixture of mass ratio of 600, 1000 and 2000 number average molecular weight.
[0033] In some preferred embodiments of the present application, the unsaturated monomer is selected from one or two of acrylic acid, 2-acrylamide 2-methylpropane sulfonic acid, sodium methacrylate sulfonate and 2-hydroxyethyl methacrylate phosphate ester; and / or
[0034] The initiator is ammonium persulfate; and / or
[0035] The reducing agent is sodium formaldehyde sulfoxylate and / or Bruggolite E51; and / or
[0036] The chain transfer agent is one or two of 3-mercaptopropionic acid, mercaptoethanol and mercaptoacetic acid.
[0037] In some preferred embodiments of the present application, the time for dropping in step S4 is 2-3 hours.
[0038] In some preferred embodiments of the present application, the conditions for the contact reaction include a temperature of 15-25℃ and a time of 2-3 hours.
[0039] To achieve the third aspect of the above object, the present application adopts the following technical solutions.
[0040] An ester polycarboxylic acid water reducer prepared by the preparation method.
[0041] Compared with the prior art, the present application has at least the following advantages or beneficial effects:
[0042] 1. The ester polycarboxylic acid water reducer provided by the present application has excellent water-reducing performance and slump retention performance, and is suitable for different concrete raw materials, which can effectively solve the problems of poor cohesion, poor wrapping, slow flow rate, segregation, and bleeding of concrete caused by material fluctuations and widespread use of inferior materials.
[0043] 2. The preparation method of the ester polycarboxylic acid water reducer provided by the present application adopts an oxidation-reduction initiation system one-step synthesis method, which can effectively shorten the synthesis time and has a simple process, without the need for harsh reaction conditions and equipment, and can be used for large-scale production. DETAILED DESCRIPTION
[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.
[0045] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict, and the present application will be described in detail below with reference to specific embodiments.
[0046] The preparation of the ester polycarboxylic acid water reducer in the present application is carried out at room temperature, i.e. 15-25℃, which does not affect the synthesis of the ester polycarboxylic acid water reducer.
[0047] The polyethylene glycol methyl acrylate with different number average molecular weights in the embodiments of the present application is purchased from Clariant Chemicals Co., Ltd.
[0048] Embodiment 1
[0049] An ester polycarboxylic acid water reducer, and a preparation method thereof, the preparation method comprising the following steps at room temperature:
[0050] (1) 80 g of polyethylene glycol methacrylate (number average molecular weight 600) was mixed with 40 g of deionized water to obtain a 1# dropping solution.
[0051] (2) 0.15 g of formaldehyde sodium sulfite, 1 g of mercapto propionic acid and 20 g of deionized water were mixed to obtain a 2# dropping solution;
[0052] (3) 21 g of acrylic acid and 20 g of deionized water were mixed to obtain a 3# dropping solution;
[0053] (4) 20 g of polyethylene glycol methacrylate (number average molecular weight 600) and 100 g of deionized water were added to a reactor, and after stirring, 0.7 g of ammonium persulfate was added, and 1# dropping solution, 2# dropping solution and 3# dropping solution were added dropwise to the reactor, the three dropping solutions were added for 2 h, and after the addition was completed, the reaction was continued for 1 h.
[0054] (5) 6 g of sodium hydroxide and 20 g of deionized water were mixed and then added to the reactor to obtain the ester-based polycarboxylic acid water reducer.
[0055] Example 2
[0056] This example is basically the same as Example 1, except that the number average molecular weight of the polyethylene glycol methacrylate is 1000.
[0057] Example 3
[0058] This example is basically the same as Example 1, except that the number average molecular weight of the polyethylene glycol methacrylate is 2000.
[0059] Example 4
[0060] This example is basically the same as Example 1, except that the polyethylene glycol methacrylate is a mixture of three products with different molecular weights, i.e. polyethylene glycol methacrylate with number average molecular weights of 600, 1000 and 2000 are mixed in equal mass proportions of 1:1:1.
[0061] Example 5
[0062] This example is basically the same as Example 4, except that the unsaturated monomer in step (3) is a mixture of 20 g of acrylic acid and 2 g of 2-hydroxyethyl methacrylate phosphate ester.
[0063] Example 6
[0064] This example is basically the same as Example 4, except that the unsaturated monomer in step (3) is a mixture of 20 g of acrylic acid and 2 g of 2-acrylamide 2-methylpropane sulfonic acid.
[0065] Comparative Example 1
[0066] The comparative example is basically the same as example 6, except that no formaldehyde sodium bisulfite is added.
[0067] Comparative Example 2
[0068] The comparative example is basically the same as example 6, except that the reaction temperature in step (4) is 70°C.
[0069] The results show that the reaction explodes to form a colloid after about 1 hour, and the synthesis fails.
[0070] Comparative Example 3
[0071] The water-reducing agent sample prepared according to comparative patent CN105294951A example 4.
[0072] Test Example 1
[0073] The ester polycarboxylic acid water-reducing agents prepared in examples 1-6 are subjected to homogeneity tests such as appearance, density, and neat paste fluidity according to the test method specified in GBT8077-2012 "Test method for homogeneity of concrete admixtures", and the test results are shown in Table 1.
[0074] Table 1 Homogeneity test results of ester polycarboxylic acid water-reducing agents prepared in examples 1-6
[0075]
[0076] As can be seen from the data in Table 1, the detection results of the ester polycarboxylic acid water-reducing agents prepared in examples 1-6, comparative examples 1 and 3 of the present application all meet the requirements of GB8076-2008 "Concrete admixtures", among which the neat paste fluidity of the ester polycarboxylic acid water-reducing agent prepared in example 6 is the largest, and the water-reducing performance is the best.
[0077] Test Example 2
[0078] The ester polycarboxylic acid water-reducing agent prepared in example 6 and commercially available ester polycarboxylic acid water-reducing agent products are subjected to the following concrete tests according to relevant standards such as GB8076-2008 "Concrete admixtures", GBT8077-2012 "Test method for homogeneity of concrete admixtures", etc.
[0079] The cement in the test raw materials is two kinds of cement from different manufacturers, i.e. Haisi PO42.5 and Jin Yu PO42.5; the sand is one kind of river sand with a fineness modulus of 2.6 and another kind of machine-made sand with a fineness modulus of 3.0; the stone is a continuous gradation of 5-20 mm; sample one is VIVID-611 ester polycarboxylic acid water reducing agent from Shanghai Sanrui High Polymer Material Co., Ltd.; sample two is ester polycarboxylic acid water reducing agent from Kezhijie New Material Group Co., Ltd.; and sample three is the ester polycarboxylic acid water reducing agent prepared in Example 6 of the present application. The concrete mixing ratio is shown in Table 2, and the concrete test results are shown in Table 3.
[0080] Table 2 Concrete mixing ratio (kg / m 3 )
[0081] cement sand stone water water reducing agent 380 791 1049 180 1.0％
[0082] Table 3 Concrete test results
[0083]
[0084] As can be seen from the data in Table 3, the slump within 1 h of the ester polycarboxylic acid water reducing agent prepared in Example 6 of the present application (sample three) has little difference compared with the commercially available ester polycarboxylic acid water reducing agents (sample one and sample two), indicating that the water reducing agent provided by the present application also has excellent water reducing performance compared with the commercially available ester polycarboxylic acid water reducing agents (sample one and sample two); in terms of the state of concrete, the ester polycarboxylic acid water reducing agent prepared in Example 6 of the present application (sample three) has better adaptability to concrete prepared with different cement and sand compared with the commercially available ester polycarboxylic acid water reducing agents (sample one and sample two). The above experimental results show that the water reducing agent provided by the present application not only has excellent water reducing performance, but also has better adaptability to different concrete.
[0085] It should be noted that the above-described examples are only used to explain the present application and do not constitute any limitation on the present application. The present application is described by referring to typical examples, but it should be understood that the words used therein are descriptive and explanatory words, rather than limiting words. The present application can be modified within the scope of the claims of the present application, and the present application can be revised without departing from the scope and spirit of the present application. Although the present application described therein relates to specific methods, materials and examples, it does not mean that the present application is limited to the specific examples disclosed therein, on the contrary, the present application can be extended to all other methods and applications with the same function.
Claims
1. An ester polycarboxylic acid water reducing agent, characterized by, Prepared by using the following components by weight parts: Polyethylene glycol methacrylate 100 parts, unsaturated monomer 20-30 parts, initiator 0.7-2 parts, reducing agent 0.1-0.4 parts, chain transfer agent 1-2 parts, sodium hydroxide 4-6 parts and water 180-200 parts; The polyethylene glycol methacrylate is a mixture of number average molecular weight of 600, 1000 and 2000 in mass ratio; The unsaturated monomer is selected from one or two of acrylic acid, 2-acrylamide 2-methylpropane sulfonic acid, sodium methacrylate and 2-hydroxyethyl methacrylate phosphate ester; The initiator is ammonium persulfate; The reducing agent is sodium formaldehyde sulfoxylate and / or Bruggolite E51; The chain transfer agent is one or two of 3-mercaptopropionic acid, mercaptoethanol and mercaptoacetic acid.
2. The ester-based polycarboxylate superplasticizer according to claim 1, characterized in that, The polyethylene glycol methacrylate is prepared by ethoxylation ring opening.
3. The method for producing the ester-based polycarboxylic acid water reducer as claimed in claim 1 or 2, characterized by, Comprising the following steps: S1. Divide the polyethylene glycol methacrylate into two parts, mix the first part of polyethylene glycol methacrylate with water to obtain 1# dropping solution; S2. Mix the reducing agent, chain transfer agent and water to obtain 2# dropping solution; S3. Mix the unsaturated monomer and water to obtain 3# dropping solution; S4. Mix the second part of polyethylene glycol methacrylate with water, add the initiator, and simultaneously add 1# dropping solution, 2# dropping solution and 3# dropping solution for contact reaction, then add sodium hydroxide-water solution, to obtain the water reducing agent.
4. The production method according to claim 3, characterized by, The time for dropping in step S4 is 2-3 hours.
5. The production method according to claim 3 or 4, characterized by, The conditions for contact reaction include: temperature of 15-25℃, time of 2-3 hours.
Citation Information
Patent Citations
Preparation method of ester type polycarboxylate water reducer
CN105294951A
Method for synthesizing polycarboxylic acid water reducing agent
CN101906193A