CN111378118B

CN111378118B - Branched polyether intermediate, preparation method thereof and application thereof in preparation of phosphorus-containing group micromolecule water reducing agent with medium-low water reducing rate

Info

Publication number: CN111378118B
Application number: CN201811651190.8A
Authority: CN
Inventors: 冉千平; 杨勇; 韩正; 亓帅; 范士敏; 王涛; 马建峰; 王兵
Original assignee: Sobute New Materials Co Ltd; Bote Building Materials Tianjin Co Ltd
Current assignee: Sobute New Materials Co Ltd; Bote Building Materials Tianjin Co Ltd
Priority date: 2018-12-31
Filing date: 2018-12-31
Publication date: 2022-04-22
Anticipated expiration: 2038-12-31
Also published as: CN111378118A

Abstract

The invention provides a branched polyether intermediate, a preparation method thereof and application thereof in preparing a phosphorus-containing group micromolecule water reducing agent with a low water reducing rate. The branched polyether intermediate is obtained by firstly carrying out esterification reaction on polyether and a phosphorylation reagent to obtain polyether phosphate and then carrying out ring-opening reaction on a dihydroxy structure in the polyether phosphate and an epoxide. The phosphorus-containing group micromolecule water reducing agent with the medium-low water reducing rate is obtained by performing esterification reaction on the branched polyether intermediate and a phosphorylation reagent. The phosphorus-containing group micromolecule water reducing agent with medium and low water reducing rates has excellent slump retaining, slow setting and clay tolerance.

Description

Branched polyether intermediate, preparation method thereof and application thereof in preparation of phosphorus-containing group micromolecule water reducing agent with medium-low water reducing rate

Technical Field

The invention belongs to the field of preparation of concrete admixtures, and particularly relates to a branched polyether intermediate, a preparation method thereof and application thereof in preparation of a phosphorus-containing group micromolecule water reducing agent with medium-low water reducing rate.

Background

The water reducing agent is an indispensable additive in concrete, can reduce the dosage of concrete mixing water, improves the working performance of the concrete, and provides a premise and guarantee for the development of the concrete towards high performance.

In all varieties of water reducing agents, the more extensive contemporary polycarboxylic acid water reducing agents are used. The polycarboxylate superplasticizer has the advantages of low mixing amount, high water reducing rate, good workability and outstanding fluidity retention capacity, and is widely applied to civil or engineering projects such as buildings, railways, bridges, hydropower, nuclear power and the like.

However, with the increasing occurrence of various targeted demands in the construction industry, the defects that the polycarboxylate superplasticizer is sensitive to the fineness of cement particles, the content of stone powder, the content of mud, the content of sulfate and the like are continuously shown. Along with the reduction of high-quality sandstone aggregate, the large-scale popularization and application of machine-made sand and low-grade sandstone aggregate with high mud content become a trend, and how to improve the working performance of the water reducing agent in the low-quality sandstone aggregate is a great challenge for practitioners in the industry.

In recent years, researchers have become interested in phosphate adsorbing groups. There have been studies to confirm (Florent Dalas et al. decorating the analytical function and the side chains of comb-like hyperplastic to improve the adsorption [ J)]Cement and cement research 2015,67,21-30), the electronegativity and adsorption capacity of the phosphate group are higher than those of the sulfonic acid group and the carboxylic acid group, the adsorption on the surface of cement particles is faster, the adsorption balance can be quickly reached, and the phosphate group can be mixed with Ca in cement²⁺Forming complex to delay the hydration process of cement. At present, various patents and documents disclose a method for producing a water reducing agent containing phosphoric acid groups or phosphorous acid groups and the effects obtained thereby.

Patent CN103596993A discloses a copolymer with gem-diphosphate groups, which has a low sensitivity to clay in cement compared to polycarboxylic acid water-reducing agents. Patent CN 105837768B discloses a preparation method of a polyphosphate water reducing agent, and the phosphate water reducing agent has good water reducing and slump retaining properties. Patent CN105504297 reports a phosphorous acid concrete superplasticizer with polyethyleneimine structure. The polyether derivative can be used alone or in combination with a sulfonate water reducer, a polycarboxylic acid water reducer and the like, and can effectively improve the flowing property and slump retaining property of concrete. Patent CN102439063B discloses a low-molecular phosphoric acid water reducing agent. The water reducing agent is composed of a polyoxyalkyl chain and a phosphonic amino alkylene compound, shows a certain retardation effect, and the retardation effect can be prolonged along with the increase of the mixing amount. However, the water reducing agent has high preparation cost and difficult application.

From the above, slump retaining, retarding, water reducing and anti-clay abilities of phosphate groups including derivatives thereof are gradually recognized by practitioners in the industry. Currently, phosphate groups exist primarily as phosphite and phosphate groups. Wherein, phosphorous acid group can be connected with polyether derivative through mannich reaction, the polyether derivative is generally polyamino compound, the number of active hydrogen used for reaction on nitrogen atom is more than 2, the adsorption group is relatively concentrated, and the polyether derivative containing phosphorous acid group shows good performance.

However, in the synthesis of phosphate-based polyether derivatives, most of monophosphates and a small amount of phosphoric acid diesters are formed, and the density of the adsorption groups is not high, resulting in limited performance.

Disclosure of Invention

The invention provides a branched polyether intermediate, a preparation method thereof and application thereof in preparing a phosphorus-containing group micromolecule water reducing agent with medium and low water reducing rate. The phosphorus-containing group micromolecule water reducing agent with medium and low water reducing rates has excellent slump retaining, slow setting and clay tolerance.

The branched polyether intermediate is obtained by firstly carrying out esterification reaction on polyether and a phosphorylation reagent to obtain polyether phosphate and then carrying out ring-opening reaction on a dihydroxy structure in the polyether phosphate and an epoxide, and the preparation process is simple.

The structural formula of the branched polyether intermediate is shown in the following formula (I) when the epoxide is ethylene oxide.

The molecular weight of the polyether is 600-3000, and the structural formula of the polyether is shown as the following formula (II).

Wherein a represents the number of structural units of ethylene oxide, and a is 10-67; b represents the number of structural units of propylene oxide, and b is 0-10; in consideration of good water solubility of the water reducing agent polyether, the usage amount of the structural unit b of the propylene oxide in the polyether synthesis process is 0-20% of the mole number of the ethylene oxide.

The repeating units of the ethylene oxide and the propylene oxide of the polyether can be randomly or block copolymerized, and the arrangement sequence is not limited.

The polyether used in the present invention is synthesized by anionic polymerization using a basic catalyst known in the art, and the specific polyether synthesis process conditions are known to researchers in the art and are not described herein.

The phosphorylation reagent comprises one of phosphoric acid, phosphorus pentoxide, polyphosphoric acid and the like.

In the phosphorylation reaction, the molar ratio of phosphorus to polyether in a phosphorylation reagent is (1.01-1.1): 1.

the specific structural formula of the phosphate is shown as (III).

The epoxide comprises one of ethylene oxide, propylene oxide, glycidol, epichlorohydrin, 1, 2-butylene oxide, tetrahydrofuran and the like.

In the ring-opening reaction, the molar ratio of the epoxide to the phosphorus in the phosphating reagent in the step (1) is (2-2.2): 1.

the ring-opening reaction does not need to add extra catalyst, and the self acidity can catalyze the reaction.

The preparation method of the branched polyether intermediate comprises the following steps:

(1) firstly, adding polyether for priming, and completely adding a phosphorylation reagent under the condition of water bath heat preservation at 50-70 ℃. The method mainly aims to prevent the reaction from being too violent under the high-temperature condition, and simultaneously avoid polyether from being solidified and separated out under the low-temperature condition, which is not beneficial to the proceeding of the phosphorylation reaction. Then heating to 100-150 ℃, reacting for 5-24 h under the negative pressure condition of-0.05 MPa-0.1 MPa to obtain the polyether phosphate,

(2) carrying out ring-opening reaction on the polyether phosphate obtained in the step (1) and an epoxide at the temperature of 80-120 ℃ for 1-10 h to obtain the branched polyether intermediate

The application of the branched polyether intermediate is used for synthesizing a phosphorus acid group-containing micromolecule water reducing agent with medium and low water reducing rate.

The phosphorus-containing group micromolecule water reducing agent with the medium-low water reducing rate is obtained by utilizing a dihydroxyl structure in the branched polyether intermediate to perform esterification reaction with a phosphorylation reagent. The structural formula of the phosphorus group-containing micromolecule water reducing agent with medium and low water reducing rates is shown in IV by taking the case that the epoxide used by the branched polyether intermediate is ethylene oxide as an example.

In the phosphorylation reaction, the molar ratio of phosphorus in a phosphorylation reagent to hydroxyl in a branched polyether intermediate is (1.01-1.5): 1.

the reaction reagents and reaction conditions used in the reaction are the same as those in the step (1), and are not described in detail.

The product of the phosphorylation reaction contains a plurality of hydroxyl groups, and can continue to open the ring of the epoxy compound and continue the esterification reaction, thereby further increasing the number of the adsorption groups, which can be used as a variation of the invention and is not described herein.

The beneficial results are that: the invention provides a preparation method of a phosphorus-containing group micromolecule water reducing agent with a medium and low water reducing rate, which has simple preparation process, excellent slump retaining, retardation and clay tolerance.

According to the invention, the phosphorus-containing group micromolecule water reducing agent is polyether phosphate with branched tail ends, a bidentate chelate structure is formed, the density of a phosphoric acid adsorption group is higher, the steric effect is obvious, and the adsorption performance and the water reducing performance of the single polyether phosphate water reducing agent are improved.

Detailed description of the preferred embodiments

The present invention is described in detail below by way of examples, which are intended to be illustrative only and not to be construed as limiting the scope of the invention, and one skilled in the art will be able to make variations within the scope of the invention based on the disclosure herein, in reagents, catalysts and reaction process conditions. All equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

In the embodiment of the invention, the yield of the synthesized polyether phosphate in the step (1) can be identified by liquid chromatography, the model of the used column is a Bioband GP120-C185 mu m120 Lambda 250mm multiplied by 4.6mm reversed phase column, the mobile phase is methanol and water, and the volume ratio is 4: 1, flow rate 1 ml/min. The number average molecular weight of the final water reducing agent product was determined using a gel permeation chromatograph. (gel column: Shodex SB806+803 column in series; eluent: 0.1M NaNO3 solution; mobile phase velocity: 0.8 ml/min; injection: 20. mu.l of 0.5% aqueous solution; detector: Shodex RI-71 type differential refraction detector; standard: polyethylene glycol GPC standard (Sigma-Aldrich, molecular weight 1010000, 478000, 263000, 118000, 44700, 18600, 6690, 1960, 628, 232)

In the application embodiment of the invention, except for special description, the adopted cement is reference cement (P.042.5), the sand is medium sand with fineness modulus Mx of 2.6, and the stones are continuous graded broken stones with the particle size of 5-20 mm. The fluidity test of the cement paste is carried out according to the GB/T8077-2000 standard, the water adding amount is 87g, and the fluidity of the cement paste is measured on plate glass after stirring for 3 min. The test method of the gas content and the water reducing rate is carried out according to the relevant regulations of GB8076-2008 concrete admixture. Slump and slump loss were carried out according to the instructions of JC473-2001, concrete Pump (concrete Pump).

In the embodiment, the parts are specifically parts by mass, and the addition amount of other materials is converted into parts by mass.

Example 1

Preparation of polyether phosphate P-1

600 parts of methoxy polyether (Mn 600, a 13, b 0) are weighed into a reactor, and 121 parts of 85% phosphoric acid are added under the condition of water bath heat preservation at 50-70 ℃. Then transferring the mixture into an oil bath, raising the temperature to 120 ℃, keeping the reaction pressure between-0.05 MPa and-0.1 MPa, and keeping the temperature for reaction for 15 hours to obtain a brown yellow product, wherein the yield of the polyether phosphate P-1 is 98.2 percent through liquid phase test.

In the same manner, the following polyether phosphate can be obtained.

P-2: obtained from methoxypolyether (Mn ═ 1000, a ═ 21, b ═ 1) in 97.4% yield of polyether phosphate.

P-3: obtained from methoxypolyether (Mn: 1500, a: 30, b: 3) in 95.5% yield.

P-4: obtained from methoxypolyether (Mn ═ 2000, a ═ 38, b ═ 5) in 93.8% yield of polyether phosphate.

P-5: obtained from methoxypolyether (Mn ═ 2500, a ═ 45, b ═ 9) in a yield of 91.6% of polyether phosphate.

P-6: obtained from methoxypolyether (Mn ═ 3000, a ═ 65, b ═ 2) in 89.5% yield of polyether phosphate.

Example 2

Adding the P-1300 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 80 ℃, introducing 44 parts of ethylene oxide into the reaction kettle, and continuing to perform heat preservation reaction for 1 hour to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring-opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature within the range, adding 71.7 parts of a phosphorylation reagent phosphorus pentoxide, transferring the reaction bottle into an oil bath, raising the temperature of the reaction system to 100 ℃, and reacting for 12 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent, wherein the molecular weight is 884 and the molecular weight distribution is 1.03 through GPC test.

Example 3

Adding P-2500 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 90 ℃, introducing 60.9 parts of propylene oxide into the reaction kettle, and continuing to perform heat preservation reaction for 3 hours to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring-opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature within the range, adding 121 parts of phosphoric acid with the concentration of 85% as a phosphorylation reagent, transferring the reaction bottle into an oil bath, raising the temperature of the reaction system to 110 ℃, and reacting for 5 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent with the molecular weight of 1312 and the molecular weight distribution of 1.02 measured by GPC.

Example 4

Adding the P-3750 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 100 ℃, introducing 75.9 parts of glycidol into the reaction kettle, and continuing to perform heat preservation reaction for 2 hours to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring-opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature within the range, adding 195.2 parts of a phosphorylation reagent polyphosphoric acid, transferring the reaction bottle into an oil bath, raising the temperature of the reaction system to 120 ℃, and reacting for 14 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent, wherein the molecular weight is 1986 and the molecular weight distribution is 1.06 according to GPC (gel permeation chromatography) test.

Example 5

Adding P-41000 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 95 ℃, introducing 99.5 parts of epoxy chloropropane into the reaction kettle, and continuing to perform heat preservation reaction for 5 hours to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature within the range, adding 81.6 parts of a phosphorylation reagent, namely phosphorus pentoxide, transferring the reaction bottle into an oil bath, raising the temperature of the reaction system to 130 ℃, and reacting for 9 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent, wherein the molecular weight is 2381 according to a GPC test, and the molecular weight distribution is 1.10.

Example 6

Adding P-51250 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 110 ℃, introducing 73.2 parts of 1, 2-epoxybutane into the reaction kettle, and continuing to perform heat preservation reaction for 10 hours to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring-opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature range, adding 138.3 parts of a phosphorylation reagent poly 85% phosphoric acid, transferring the reaction bottle into an oil bath, raising the temperature of the reaction system to 140 ℃, and reacting for 7 hours under the pressure condition of-0.05-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent, wherein the molecular weight is 2840 through GPC test, and the molecular weight distribution is 1.15.

Example 7

Adding P-61500 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 120 ℃, introducing 75 parts of tetrahydrofuran into the reaction kettle, and continuing to perform heat preservation reaction for 9 hours to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature within the range, adding 110.9 parts of a phosphorylation reagent polyphosphoric acid, transferring the reaction bottle to an oil bath, raising the temperature of the reaction system to 150 ℃, and reacting for 16 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent, wherein the molecular weight is 3340 according to GPC test, and the molecular weight distribution is 1.16.

Example 8

Adding the P-1300 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 115 ℃, introducing 81.4 parts of glycidol into the reaction kettle, and continuing to perform heat preservation reaction for 8 hours to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring-opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature range, adding 92.3 parts of a phosphorylation reagent, namely phosphorus pentoxide, transferring the reaction bottle into an oil bath, raising the temperature of the reaction system to 145 ℃, and reacting for 18 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent, wherein the molecular weight is 1140 and the molecular weight distribution is 1.04 according to GPC test.

Example 9

Adding the P-3750 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 85 ℃, introducing 63.2 parts of propylene oxide into the reaction kettle, and continuing to perform heat preservation reaction for 7 hours to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring-opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature range, adding 172.9 parts of phosphoric acid with the concentration of poly 85% as a phosphorylation reagent, transferring the reaction bottle into an oil bath, raising the temperature of the reaction system to 135 ℃, and reacting for 20 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent with the molecular weight of 1812 and the molecular weight distribution of 1.07 through GPC test.

Example 10

Adding P-51250 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 105 ℃, introducing 47.5 parts of ethylene oxide into the reaction kettle, and continuing to perform heat preservation reaction for 4 hours to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring-opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature within the range, adding 124.2 parts of a phosphorylation reagent polyphosphoric acid, transferring the reaction bottle to an oil bath, raising the temperature of the reaction system to 125 ℃, and reacting for 24 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent, wherein the molecular weight is 2784 through GPC test, and the molecular weight distribution is 1.11.

Comparative example 1

Adding P-2500 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 112 ℃, introducing 69.6 parts of propylene oxide into the reaction kettle, and continuing to perform heat preservation reaction for 0.5h to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring-opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature within the range, adding 102.9 parts of a phosphorylation reagent, namely phosphorus pentoxide, then transferring the reaction bottle into an oil bath, raising the temperature of the reaction system to 115 ℃, and reacting for 3 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus group-containing micromolecule water reducing agent, wherein the molecular weight is 1312 according to the GPC test, and the molecular weight distribution is 1.30.

Comparative example 2

Adding P-41000 parts into a reaction kettle, and vacuumizing the reaction kettle to-0.1 MPa at room temperature. And then heating the reaction kettle to 70 ℃, introducing 95.3 parts of epichlorohydrin into the reaction kettle, and continuing to perform heat preservation reaction for 5 hours to stop the reaction when the pressure in the reaction kettle is reduced and the temperature is slightly increased, which indicates that the ring-opening reaction starts. And opening an emptying valve to balance the pressure in the reaction kettle, and opening the reaction kettle to discharge. Transferring the feed liquid into a reaction bottle, putting the reaction bottle into a water bath to reduce the temperature of the system to 50-70 ℃, maintaining the temperature range, adding 196 parts of phosphoric acid with the concentration of 85% of the phosphorylation reagent, transferring the reaction bottle into an oil bath, raising the temperature of the reaction system to 105 ℃, and reacting for 10 hours under the pressure condition of-0.05 to-0.1 MPa to obtain the phosphorus-containing group micromolecule water reducing agent with the molecular weight of 2381 and the molecular weight distribution of 1.23 measured by GPC.

Application example 1

The fluidity test of the cement paste is carried out according to the GB/T8077-2000 standard, 300g of reference cement is adopted, the water adding amount is 87g, and the fluidity of the cement paste is measured on plate glass after the stirring for 3 min. The results are shown in Table 1.

TABLE 1 Cement paste fluidity test results

The results in Table 1 show that the phosphorus-containing group micromolecule water reducing agent has a water reducing effect of medium and low degree, but has better slump retaining capability on cement.

Application example 2

The test method of the gas content and the water reducing rate is carried out according to the relevant regulations of GB8076-2008 concrete admixture. The slump of the fresh concrete of the water reducer and the change of slump over time of 60min and 120min are determined by referring to a related method of JC473-2001 concrete pumping aid, the mixing amount of the phosphorus-group-containing micromolecule water reducer is fixed to be 0.6 percent of the cement dosage, and the experimental results are shown in Table 2.

TABLE 2 test results of gas content, water reducing rate and slump of concrete

As can be seen from the concrete test results in Table 2, the phosphorus-containing group micromolecule water reducing agent disclosed by the invention has good slump retaining performance, certain retarding capacity and good air entraining performance.

Application example 3

To evaluate the sensitivity of the phosphorus group containing small molecule water reducing agent of the present invention to clay, the fluidity of the mortar with clay-containing sand configuration was tested. The testing of the expansion degree of the mortar refers to GB/T17671-1999 measuring method of cement mortar fluidity, wherein the used cement is reference cement, the mortar ratio is 1: 3; clay replaces 0.5 percent of the sand by mass; the water-cement ratio was 0.44. The fluidity of the fresh mortar containing the phosphorus group micromolecule water reducing agent and the change of the fluidity of the fresh mortar with time of 60min and 120min are measured. The results are shown in Table 3.

TABLE 3 mortar fluidity test results

From the results in table 3, it can be seen that the phosphorus group-containing small molecule water reducing agent of the present invention has good resistance to clay in sand.

Claims

1. A branched polyether intermediate is characterized in that polyether and a phosphorylation reagent are subjected to phosphorylation reaction to obtain polyether phosphate, and then a dihydroxy structure in the polyether phosphate and an epoxide are subjected to ring-opening reaction to obtain the branched polyether intermediate;

the molecular weight of the polyether is 600-3000, and the structural formula of the polyether is shown as the following formula (II):

wherein a represents the number of structural units of ethylene oxide, and a is 10-67; b represents the number of structural units of propylene oxide, and b is 0-10; the usage amount of the structural unit number b of the propylene oxide in the polyether synthesis process is 0 to 20 percent of the mole number of the ethylene oxide;

the ethylene oxide and propylene oxide repeating units of the polyether are randomly or block copolymerized;

the phosphorylation reagent comprises one of phosphoric acid, phosphorus pentoxide and polyphosphoric acid;

in the phosphorylation reaction, the molar ratio of phosphorus to polyether in a phosphorylation reagent is (1.01-1.1): 1;

the epoxide comprises one of ethylene oxide, propylene oxide, glycidol, epichlorohydrin, 1, 2-butylene oxide and tetrahydrofuran;

in the ring-opening reaction, the molar ratio of the epoxide to the phosphorus in the phosphorylation reagent is (2-2.2): 1;

2. The branched polyether intermediate of claim 1, having the formula (i):

3. a process for the preparation of a branched polyether intermediate as claimed in claim 1 or 2, characterised by the steps of:

(1) firstly adding polyether for priming, finishing adding a phosphorylation reagent under the condition of 50-70 ℃ water bath heat preservation, then heating to 100-150 ℃, reacting for 5-24 h under the negative pressure condition of-0.05 MPa to-0.1 MPa to obtain polyether phosphate,

(2) and (2) carrying out ring-opening reaction on the polyether phosphate obtained in the step (1) and an epoxide at the reaction temperature of 80-120 ℃ for 1-10 h to obtain the branched polyether intermediate.

4. A phosphorus group containing micromolecule water reducing agent with medium and low water reducing rate is characterized in that the phosphorus group containing micromolecule water reducing agent is obtained by esterification reaction of the branched polyether intermediate of claim 1 and a phosphorylation reagent;

in the esterification reaction, the molar ratio of phosphorus in a phosphorylation reagent to hydroxyl in a branched polyether intermediate is (1.01-1.5): 1.

5. the phosphorus-containing group small molecule water reducing agent with the medium and low water reducing rate according to claim 4, is characterized in that the structural formula is shown as the formula (IV):