A collapse-preserving polycarboxylic acid water-reducing agent prepared from ester-terminated unsaturated polyether monomer and a preparation method thereof

Abstract

The present invention relates to a collapse-preserving polycarboxylic acid water-reducing agent prepared from an ester-terminated unsaturated polyether monomer and a preparation method thereof. The structural formula of the ester-terminated unsaturated polyether monomer is as follows: wherein R1 and R2 are (CH2) n , n is an integer of 2-8; R3 is C1-C 12 The ester-terminated unsaturated polyether monomer prepared by the present invention has various molecular structures, adjustable hydrophilicity and lipophilicity, and controllable molecular weight. Compared with the traditional collapse-retaining polycarboxylic acid water-reducing agent, the ester-terminated polyether is gradually hydrolyzed in concrete, so that the prepared water-reducing agent has a higher retention capacity.

Description

Technical Field

[0001] The invention relates to the field of admixtures, and in particular to a collapse-preserving polycarboxylic acid water-reducing agent prepared from an ester-terminated unsaturated polyether monomer and a preparation method thereof. Background Art

[0002] As one of the important raw materials for synthesizing polycarboxylic acid water reducers, the molecular structure of vinyl alcohol macromonomers has a very important influence on the synthesis process and performance of polycarboxylic acid water reducers. At present, the most common vinyl alcohol macromonomers on the market mainly include allyl polyethylene glycol ether (APEG), methyl allyl polyethylene glycol ether (HPEG) and isopentenyl polyethylene glycol ether (TPEG). Although the synthesis process of this type of macromonomer is simple, the chemical properties are stable, and the product quality is good, there are also many problems. On the one hand, among the existing vinyl alcohol macromonomers, HPEG and TPEG products account for the vast majority, and the product structure is relatively simple. On the other hand, due to the structural limitations of traditional polyether macromonomers, the water reduction and slump retention performance of polycarboxylic acid water reducers cannot be qualitatively improved. Therefore, the entire industry is in urgent need of developing more new polyether macromonomer varieties, expanding the product types and functions of macromonomers, and improving the comprehensive performance of polycarboxylic acid water reducers. Summary of the invention

[0003] In view of the prior art, the present invention develops a collapse-preserving polycarboxylic acid water-reducing agent prepared from an ester-terminated unsaturated polyether monomer and a preparation method thereof, so as to solve the problems of a single polyether monomer structure, poor concrete workability and insufficient retention performance. The water-reducing agent synthesized from an ester-terminated unsaturated polyether monomer has strong adaptability, good dispersibility and collapse-preserving performance.

[0004] Based on this, the present invention provides an ester-terminated unsaturated polyether monomer, the structural formula of the ester-terminated unsaturated polyether monomer is as follows:

[0005]

[0006] Wherein, R1 and R2 are (CH2) n , n is an integer of 2-8; R3 is C1-C 12 A straight chain or branched saturated alkyl group, a and b are integers of 0-100.

[0007] Preferably, a and b are integers of 1-70.

[0008] Furthermore, the preparation method of the ester-terminated unsaturated polyether monomer is:

[0009] Under the action of a catalyst, a terminal enol ester is used as an initiator to carry out a ring-opening polymerization reaction with ethylene oxide and / or propylene oxide at 100-120° C. and 0.2-0.5 MPa to obtain the ester-terminated unsaturated polyether monomer.

[0010] Preferably, the ring-opening polymerization reaction time is 2-4 hours.

[0011] Furthermore, the structural formula of the terminal enol ester is as follows:

[0012]

[0013] Wherein, R1 and R2 are (CH2) n , n is an integer of 2-8; R3 is C1-C 12 A straight chain or branched saturated alkyl group.

[0014] Furthermore, the amount of the terminal enol ester is 0.1-15% of the total mass of the raw materials for preparing the ester-terminated unsaturated polyether monomer;

[0015] The amount of ethylene oxide and / or propylene oxide used is 85-99% of the total mass of the raw materials for preparing the ester-terminated unsaturated polyether monomer.

[0016] Furthermore, the catalyst is a mixture of an alkaline catalyst and a rare earth metal catalyst, and the amount of the catalyst used is 0.01-0.2% of the total mass of the raw materials for preparing the ester-terminated unsaturated polyether monomer;

[0017] The alkaline catalyst includes at least one of KOH, NaOH, and CH3ONa;

[0018] The rare earth metal is lanthanum.

[0019] The second object of the present invention is to provide a collapse-retaining polycarboxylic acid water-reducing agent prepared from an ester-terminated unsaturated polyether monomer.

[0020] Furthermore, the collapse-retaining polycarboxylate water-reducing agent includes the following raw materials, by weight: 200 parts of an ester-terminated unsaturated polyether monomer, 4-10 parts of a cross-linking monomer, 5-12 parts of an unsaturated acid, 2-10 parts of a functional monomer, 0.2-3 parts of a molecular weight regulator, 0.1-2 parts of a reducing agent, 0.5-5 parts of an oxidant, and 150-300 parts of deionized water.

[0021] Furthermore, the structural formula of the cross-linking monomer is as follows,

[0022]

[0023] R4 is (CH2CH2O) m , m is an integer from 1 to 6;

[0024] The structural formula of the functional monomer is as follows:

[0025]

[0026] R5 is H or CH3, and X is CH2 or CH2CH2.

[0027] Furthermore, the unsaturated acid is at least one of acrylic acid, methacrylic acid and itaconic acid;

[0028] The reducing agent is at least one of L-ascorbic acid, azobisisopropylimidazoline hydrochloride, azobiscyclohexylcarbonitrile, sodium bisulfite, sodium pyrosulfite, chlorinated acetic acid, ferrous sulfate heptahydrate, and ammonium ferrous sulfate;

[0029] The oxidant is at least one of hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate;

[0030] The molecular weight regulator is at least one of mercaptopropionic acid, mercaptoethanol, sodium hypophosphite, mercaptopropanol, mercaptopropionic acid ester and p-phenol.

[0031] The third object of the present invention is to provide a method for preparing the above-mentioned collapse-retaining polycarboxylate water-reducing agent, which comprises at least the following steps:

[0032] S1, dividing deionized water into three parts, adding the ester-terminated unsaturated polyether monomer, the oxidant, the crosslinking monomer and the first part of deionized water into a reactor, stirring and dissolving to obtain a first mixed solution;

[0033] S2, taking the functional monomer, the unsaturated acid and the second portion of deionized water, stirring and mixing, to obtain solution A;

[0034] S3, taking the molecular weight regulator, the reducing agent and the third part of deionized water, stirring and mixing, to obtain solution B;

[0035] S4. Add solution A and solution B to the first mixed solution at the same time under stirring at room temperature; after the addition is completed, add alkali to neutralize the pH to 5-7, so as to obtain the collapse-retaining polycarboxylic acid water-reducing agent.

[0036] Specifically, the mass ratio of the first part of deionized water, the second part of deionized water, and the third part of deionized water is (150-250):20:30.

[0037] In summary, the present invention has the following beneficial effects:

[0038] 1. The ester-terminated unsaturated polyether monomer prepared by the present invention has diverse molecular structures, adjustable hydrophilicity and lipophilicity, and controllable molecular weight. Compared with the traditional collapse-retaining polycarboxylic acid water-reducing agent, as the cement hydration proceeds, the concrete solution is strongly alkaline, and the ester-terminated polyether will gradually hydrolyze in an alkaline environment, and the released carboxyl groups will continuously adsorb and disperse the cement particles, thereby ensuring that the concrete can have good fluidity for a long time. Therefore, the prepared water-reducing agent has a higher retention capacity.

[0039] 2. The present invention introduces a new branched structure into the ester-terminated unsaturated polyether monomer molecule to form a hydrophobic unit in the water reducer, thereby overcoming the problem that the water reducer synthesized from traditional straight-chain monomers is prone to water exudation and segregation, resulting in poor workability of concrete, and thus greatly improving the slump retention performance of the synthesized polycarboxylic acid water reducer.

[0040] 3. The present invention introduces a cross-linking monomer into the molecular structure of the polycarboxylate water-reducing agent, so that the prepared polycarboxylate water-reducing agent molecules present a micro-cross-linking structure, which can effectively lock the moisture in the concrete, thereby further improving the water retention of the polycarboxylate water-reducing agent. DETAILED DESCRIPTION

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials and reagents used in the following examples are all commercially available unless otherwise specified. The quantitative tests in the following examples were performed in triplicate, and the data are the average or average ± standard deviation of the triplicate experiments.

[0043] In addition, the "and / or" in the full text includes three solutions. Taking A and / or B as an example, it includes technical solution A, technical solution B, and a technical solution that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.

[0044] Example 1

[0045] The preparation method of the ester-terminated unsaturated polyether monomer is as follows:

[0046] 56.5g of initiator, 1.5g of CH3ONa and 0.06g of rare earth metal lanthanum catalyst were added to a reactor, wherein the structural formula of the initiator was: CH2=CH-O-CH2CH2-O-CH2CH2-OOC-CH2CH3, and the pre-reaction temperature was controlled to be 35°C, and the pre-reaction time was 0.8 hour; after the pre-reaction was completed, the temperature was heated and vacuumed at 90°C, and then replaced with nitrogen, the temperature was raised to 100°C, 529g of ethylene oxide was introduced, the reaction temperature was controlled at 105°C and a pressure of 0.35MPa, and the reaction was continued until the pressure no longer decreased, 331g of propylene oxide was continuously introduced, the reaction temperature was controlled at 105°C and a pressure of 0.35MPa, and the reaction was continued until the pressure no longer decreased; after the reaction was completed, the temperature was lowered to 60°C and the material was discharged to obtain an ester-terminated unsaturated polyether monomer.

[0047] A collapse-retaining polycarboxylate water-reducing agent, comprising the following raw materials in parts by mass:

[0048] 200 parts of ester-terminated unsaturated polyether monomer, 5 parts of crosslinking monomer, 5 parts of acrylic acid, 6 parts of allyl glycidyl ether, 1 part of mercaptopropionic acid, 0.5 parts of L-ascorbic acid, 2.0 parts of hydrogen peroxide, and 220 parts of deionized water.

[0049] The molecular weight of the ester-terminated unsaturated polyether monomer is 3000, and its structural formula is: CH2=CH-O-CH2CH2-O-CH2CH2-O-(CH2CH2O) a -(CH2CH3CHO) b -OC-CH2CH3;

[0050] The structural formula of the cross-linking monomer is:

[0051] CH2=CH-O-CH2CH2O-CH2CH2O-CH2CH2O-CH=CH2.

[0052] The preparation method of the above-mentioned collapse-retaining polycarboxylate water-reducing agent is as follows:

[0053] S1, adding an ester-terminated unsaturated polyether monomer, hydrogen peroxide, a crosslinking monomer and 170 parts of deionized water into a reactor, stirring and dissolving to obtain a first mixed solution;

[0054] S2, taking allyl glycidyl ether, acrylic acid and 20 parts of deionized water, stirring and mixing, to obtain solution A;

[0055] S3, taking mercaptopropionic acid, L-ascorbic acid and 30 parts of deionized water, stirring and mixing to obtain solution B;

[0056] S4. Under stirring at room temperature, solution A and solution B are added dropwise to the first mixed solution at the same time; after the addition is completed, alkali is added to neutralize the pH to 6, thereby obtaining a collapse-retaining polycarboxylic acid water-reducing agent.

[0057] Example 2

[0058] The preparation method of the ester-terminated unsaturated polyether monomer is as follows:

[0059] 76.2 g of initiator, 1.5 g of KOH and 0.02 g of rare earth metal lanthanum catalyst were added into a reactor, wherein the structural formula of the initiator is: CH2=CH-O-CH2CH2-O-CH2CH2-OOC-CH2CH3, the pre-reaction temperature was controlled to be 35°C, and the pre-reaction time was 0.8 hour; after the pre-reaction was completed, the temperature was heated and vacuumed at 90°C, and then replaced with nitrogen, the temperature was raised to 100°C, 1142 g of ethylene oxide was introduced, the reaction temperature was controlled to be 105°C, and the pressure was 0.35 MPa, and the reaction was carried out until the pressure no longer decreased; after the reaction was completed, the temperature was lowered to 60°C and the material was discharged to obtain an ester-terminated unsaturated polyether monomer.

[0060] A collapse-retaining polycarboxylate water-reducing agent, comprising the following raw materials in parts by mass:

[0061] 200 parts of ester-terminated unsaturated polyether monomer, 6 parts of crosslinking monomer, 12 parts of acrylic acid, 8 parts of glycidyl methacrylate, 1.5 parts of mercaptoethanol, 0.5 parts of L-ascorbic acid, 2.5 parts of hydrogen peroxide, and 220 parts of deionized water.

[0062] The molecular weight of the ester-terminated unsaturated polyether monomer is 3000, and its structural formula is: CH2=CH-O-CH2CH2-O-CH2CH2-O-(CH2CH2O) a -OC-CH2CH3;

[0063] The structural formula of the cross-linking monomer is: CH2=CH-O-CH2CH2O-CH2CH2O-CH=CH2.

[0064] The preparation method of the collapse-resistant polycarboxylic acid water-reducing agent in Example 2 is the same as that in Example 1.

[0065] The difference between Comparative Example 1 and Example 1 is that the ester-terminated unsaturated polyether monomer is replaced by ethylene glycol monovinyl polyoxyethylene ether with the same molecular weight and the same mass fraction.

[0066] The difference between Comparative Example 2 and Example 1 is that no crosslinking monomer is added.

[0067] The difference between Comparative Example 3 and Example 1 is that no functional monomer is added.

[0068] Comparative Example 4: The collapse-preventing agent is S10E collapse-preventing agent produced by Fujian Kezhijie New Materials Group Co., Ltd. The mother liquor of the collapse-preventing agent is obtained by copolymerizing isopentanol polyoxyethylene ether, acrylic acid, and hydroxyethyl acrylate in a redox system. The molecular structure of the mother liquor is:

[0069]

[0070] Concrete performance testing

[0071] The concrete mix ratio is shown in Table 1, where the cement used is Minfu P.O42.5 ordinary Portland cement; the machine-made sand is matched with stone powder, the machine-made sand fineness modulus is 2.8, the mud content is 4.5% and the powder content is relatively high; the stone powder fineness modulus is 2.7, and the mud content is 14.9%.

[0072] Table 1 Concrete mix ratio (unit: kg / m 3 )

[0073] cement Fly ash Mineral powder Stone powder Machine-made sand Stone water 220 50 80 150 780 900 175

[0074] The collapse-retaining polycarboxylate water reducer prepared in each embodiment and comparative example was compounded in an equal ratio of water reducer mother liquor: collapse-retaining polycarboxylate water reducer: water = 6:4:40, wherein the water reducer mother liquor was uniformly HPEG polycarboxylate water reducer produced by Fujian Kezhijie New Materials Group Co., Ltd.

[0075] The test method is based on GB / T 8076-2008 "Concrete Admixtures", GB / T 50080-2016 "Standard for Test Methods for Performance of Ordinary Concrete Mixtures", and GB / T 50081-2019 "Standard for Test Methods for Physical and Mechanical Properties of Concrete". The test results are shown in Table 2.

[0076] Table 2 Performance test results

[0077]

[0078] As shown in Table 2, the product of the embodiment has a high water reduction rate and good slump retention performance, the initial concrete flow rate is fast, the workability is good, and there is no water seepage, while the comparative example 1 uses ethylene glycol monovinyl polyoxyethylene ether, and the 1h slump retention performance decreases significantly; the comparative example 2 does not add a cross-linking monomer, and although the initial state is better, the concrete loses quickly in 2h; the comparative example 3 does not add a functional monomer, the concrete state is obviously worse, the exposed stone is obvious, and there is more water seepage; the comparative example 4 loses quickly in both 1h and 2h, and there is more water seepage.

[0079] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for preparing an ester-terminated unsaturated polyether monomer, characterized in that: The structural formula of the ester-terminated unsaturated polyether monomer is as follows: ， Wherein, R1 and R2 are (CH2) n , n is an integer of 2-8; R3 is C1-C 12 A straight or branched saturated alkyl group, a and b are integers from 0 to 100, and a and b are not 0 at the same time; The preparation method of the ester-terminated unsaturated polyether monomer is as follows: Under the action of a catalyst, a terminal enol ester is used as an initiator to carry out a ring-opening polymerization reaction with ethylene oxide and / or propylene oxide at 100-120° C. and 0.2-0.5 MPa to obtain the ester-terminated unsaturated polyether monomer; The catalyst is a mixture of an alkaline catalyst and a rare earth metal catalyst, and the alkaline catalyst includes at least one of KOH, NaOH, and CH3ONa; The rare earth metal is lanthanum.

2. The method for preparing an ester-terminated unsaturated polyether monomer according to claim 1, characterized in that: The structural formula of the terminal enol ester is as follows: ， Wherein, R1 and R2 are (CH2) n , n is an integer of 2-8; R3 is C1-C 12 A straight chain or branched saturated alkyl group.

3. The method for preparing an ester-terminated unsaturated polyether monomer according to claim 1, characterized in that: The amount of the terminal enol ester is 0.1-15% of the total mass of the raw materials for preparing the ester-terminated unsaturated polyether monomer; The amount of ethylene oxide and / or propylene oxide used is 85-99% of the total mass of the raw materials for preparing the ester-terminated unsaturated polyether monomer.

4. The method for preparing an ester-terminated unsaturated polyether monomer according to claim 1, characterized in that: The amount of the catalyst used is 0.01-0.2% of the total mass of the raw materials for preparing the ester-terminated unsaturated polyether monomer.

Images