A water reducing agent, its preparation method and application

Abstract

The application relates to the technical field of building materials, and particularly discloses a water reducing agent and a preparation method and application thereof. The water reducing agent disclosed by the application comprises the following components in parts by weight: 30-35 parts of a six-carbon monomer, 2-4 parts of a small monomer, 2-3 parts of a slow-release monomer, 1-2 parts of a functional monomer, 0.5-1 part of a chain transfer agent, 0.1-0.5 parts of a reducing agent, 0.1-0.5 parts of an oxidizing agent, 1-3 parts of a pH regulator, 1-3 parts of an anti-caking agent and 50-60 parts of soft water. Meanwhile, the application also discloses a preparation method of the water reducing agent. The water reducing agent provided by the application can effectively improve the fluidity of a gypsum-based self-leveling mortar, can reduce a flow loss, and can further improve a fluidity retention rate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of building materials, and in particular to a water reducing agent and a preparation method and application thereof. BACKGROUND

[0002] Gypsum is a kind of green building material, and due to its rich resources and simple processing, gypsum products are widely used. Gypsum-based self-leveling mortar is a kind of dry mortar powder specially used for ground leveling, which is prepared and mixed uniformly in a factory by using gypsum cementing material, aggregate and various building admixtures. The gypsum-based self-leveling mortar has the following advantages: it can be pumped for construction, and the operation is easy, convenient and efficient; the ground constructed by using the gypsum-based self-leveling mortar has the advantages of accurate size, high levelness, no hollowing and no cracking, and has good heat preservation performance and sound insulation effect. Therefore, the gypsum-based self-leveling mortar has a broad application prospect.

[0003] The development of gypsum-based self-leveling mortar building materials is also subject to certain restrictions: the theoretical gypsum-water ratio of building gypsum (semi-hydrated gypsum) is 18.6%, while the actual gypsum-water ratio is 60-80%, which reduces the strength of building gypsum. One of the key technologies to improve the strength of building gypsum is to use gypsum water reducing agent.

[0004] However, due to the lack of systematic research on gypsum water reducing agent, the development of gypsum water reducing agent tends to lag behind. At present, the basic research on gypsum water reducing agent is much weaker than that on concrete water reducing agent, and the research on the structure, adsorption characteristics, action mechanism and adaptability of gypsum water reducing agent is very little, which leads to the fact that the theory of concrete water reducing agent is copied in the application of gypsum water reducing agent. There is no special polycarboxylic acid water reducing agent for gypsum, and most of the polycarboxylic acid water reducing agents for concrete are still used in stone building materials. Although there are many similarities between cement-based building materials and gypsum-based building materials, completely following the theory is not conducive to the development of gypsum building materials.

[0005] With the development of the construction industry, the requirements for water reducing agents in engineering applications are gradually increasing. As an important high-performance water reducing agent, polycarboxylic acid water reducing agent has the advantages of high water reducing rate, high fluidity, strong dispersing ability, low dosage, strong molecular structure design, and small flow loss, and has been greatly popularized and applied.

[0006] In the gypsum-based self-leveling mortar, the fluidity and flow loss of the gypsum-based self-leveling mortar have always been a difficult problem in construction, especially after short-time stirring on site, which affects the leveling performance of the gypsum-based self-leveling mortar, and especially after a period of storage, the leveling performance is greatly reduced. If water is added to reshape, the actual strength and durability of the gypsum-based self-leveling mortar cannot meet the index requirements. If water reducing agent or on-site water supplement is added, these measures are complicated to operate, increase the cost and have poor safety.

[0007] In addition, due to rich gypsum resources, and a wide variety of, raw material regional difference is big, etc., resulting in product fluctuation is bigger; even meet the initial flowability of gypsum self-leveling mortar, but the flow loss is more serious, it is difficult to guarantee the requirements of construction. SUMMARY

[0008] In order to improve the flowability of gypsum-based self-leveling mortar, while reducing the flow loss, the application provides a water reducing agent and its preparation method and application.

[0009] In the first aspect, the application provides a water reducing agent.

[0010] A water reducing agent, comprising the following components by weight: 30-35 parts of six-carbon monomer, 2-4 parts of small monomer, 2-3 parts of slow-release monomer, 1-2 parts of functional monomer, 0.5-1 parts of chain transfer agent, 0.1-0.5 parts of reducing agent, 0.1-0.5 parts of oxidizing agent, 1-3 parts of pH regulator, 1-3 parts of anti-caking agent, 50-60 parts of soft water;

[0011] The small monomer is selected from one or more of acrylic acid, methacrylic acid;

[0012] The slow-release monomer is selected from one or more of hydroxypropyl acrylate, hydroxyethyl acrylate;

[0013] The functional monomer is selected from one or more of 2-acrylamido-2-methylpropane sulfonic acid, sodium methacrylate sulfonate, sodium allyl sulfonate.

[0014] Through multiple tests, it is found that the water reducing agent prepared by the above formula applied to gypsum-based self-leveling mortar can significantly improve the flowability of gypsum-based self-leveling mortar, while effectively reducing the flow loss of gypsum-based self-leveling mortar, so that the flowability retention rate of gypsum-based self-leveling mortar is good.

[0015] The water reducing agent disclosed in the application has carboxylic acid, hydroxyl, vinyl and amino groups in its structure, and the product is polymerized to fully exert the synergistic effect between the components. Due to the introduction of functional monomers with sulfonic acid structure, the steric hindrance is large, so that the water reducing agent applied to gypsum-based self-leveling mortar has excellent high flowability effect and retention effect. The ester group structure in the structure of the water reducing agent can hydrolyze and release carboxylic acid groups with water reducing effect under alkaline conditions, so that the water reducing agent has outstanding durability.

[0016] Preferably, the six-carbon monomer is selected from one or more of hydroxyethyl-3-butenyl ether, hydroxypropyl allyl ether, diethylene glycol monovinyl ether, isopentenyl alcohol polyoxyethylene ether, and 4-hydroxybutyl vinyl ether.

[0017] Preferably, the six-carbon monomer is isopentenyl alcohol polyoxyethylene ether.

[0018] Further, the molecular weight of the isopentenol polyoxyethylene ether is 3000-5000.

[0019] In a specific embodiment, the molecular weight of the isopentenol polyoxyethylene ether can be 3000, 4000, 5000.

[0020] In some specific embodiments, the molecular weight of the isopentenol polyoxyethylene ether can also be 3000-4000, 4000-5000.

[0021] The applicant found in the test process that when using isopentenol polyoxyethylene ether as a six-carbon monomer, the molecular weight of the isopentenol polyoxyethylene ether will significantly affect the flow loss of the gypsum-based self-leveling mortar, and when the molecular weight of the isopentenol polyoxyethylene ether is controlled to be in the above range, the flow loss of the gypsum-based self-leveling mortar can be significantly reduced.

[0022] Preferably, the functional monomer is sodium methallyl sulfonate and sodium allyl sulfonate in a weight ratio of (1-1.3):(0.2-0.5).

[0023] In a specific embodiment, the weight ratio of the sodium methallyl sulfonate and the sodium allyl sulfonate can be 1:0.2, 1:0.3, 1:0.5, 1.2:0.2, 1.2:0.3, 1.2:0.5, 1.3:0.2, 1.3:0.3, 1.3:0.5.

[0024] In some specific embodiments, the weight ratio of the sodium methallyl sulfonate and the sodium allyl sulfonate can also be (1-1.2):0.2, (1-1.2):0.3, (1-1.2):0.5, (1.2-1.3):0.2, (1.2-1.3):0.3, (1.2-1.3):0.5, 1.3:(0.2-0.3), 1.3:(0.3-0.5), 1.3:(0.2-0.5).

[0025] Through test analysis, it can be known that when the functional monomer is controlled to be the sodium methallyl sulfonate and the sodium allyl sulfonate in the above weight ratio, the fluidity of the gypsum-based self-leveling mortar can be further improved, and the flow loss of the gypsum-based self-leveling mortar is reduced.

[0026] Preferably, the oxidizing agent is selected from one or more of hydrogen peroxide, potassium persulfate, and ammonium persulfate.

[0027] Preferably, the oxidizing agent is hydrogen peroxide.

[0028] Preferably, the pH regulator is selected from one or more of sodium bicarbonate, sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

[0029] Preferably, the pH regulator is sodium hydroxide.

[0030] Preferably, the chain transfer agent is selected from one or more of mercaptopropionic acid, mercaptoethanol.

[0031] Preferably, the reducing agent is selected from one or more of ascorbic acid, sodium formaldehyde sulfoxylate, E51.

[0032] Preferably, the anti-caking agent is selected from one or more of calcined kaolin, fumed silica, ground calcium powder.

[0033] Preferably, the water reducing agent further comprises a modifier 0.01-0.1 parts; the modifier comprises a weight ratio of (0.5-1.5):(0.5-1.5) silane defoaming agent and polyether air entraining agent.

[0034] The present application introduces a modifier of silane structure and polyether structure into the water reducing agent, which is applied to the gypsum-based self-leveling, and has a more obvious effect of reducing the surface tension of the solution than the conventional carbon-carbon structure; the small closed gas structure is introduced, so that the hydrophobicity is reduced, and the subsequent spray drying of the water reducing agent powder is facilitated.

[0035] Through test analysis, it is known that when the above-mentioned modifier is added into the water reducing agent, the large bubbles can be eliminated, and the closed small bubbles are introduced; at the same time, the application performance of the water reducing agent in the gypsum-based self-leveling mortar can be further improved, so that the fluidity of the gypsum-based self-leveling mortar is further improved, and the flow loss of the gypsum-based self-leveling mortar is reduced.

[0036] In the second aspect, the present application provides a preparation method of the above-mentioned water reducing agent, which specifically comprises the following steps:

[0037] Under normal temperature conditions, water, a six-carbon monomer and a functional monomer are mixed, the temperature of the mixed system is adjusted to 16-20℃, then 1 / 3 of the amount of a small monomer is added for mixing, and the temperature is controlled to be unchanged, to obtain component A;

[0038] The remaining 2 / 3 of the amount of the small monomer, a chain transfer agent and a slow-release monomer are mixed to obtain component B;

[0039] The reducing agent is diluted with water by 8-10 times to obtain component C;

[0040] The component B and the component C are simultaneously added dropwise into the component A, the dropwise adding time of the component B is controlled to be 30-50 min, and the dropwise adding time of the component C is controlled to be 60-80 min; after the dropwise adding of both is completed, the temperature is kept for 1 h, the pH regulator is added, stirring is carried out for 20-40 min, the anti-caking agent is added, and stirring is continued for 20-40 min;

[0041] After spray drying, the water reducing agent is obtained.

[0042] The application performance of the water reducing agent obtained by screening the raw material addition sequence and controlling the reaction temperature in the reaction system of component A is excellent, which can effectively improve the fluidity of the gypsum-based self-leveling mortar and reduce the flow loss of the gypsum-based self-leveling mortar.

[0043] In addition, the preparation method provided by the application is a free radical polymerization reaction, and the reaction temperature in the reaction system of component A and the low-valence time of components B and C are controlled, so that the reaction temperature does not need to be monitored in the subsequent preparation process, thereby further optimizing the preparation process of the water reducing agent. The preparation method provided by the application can replace the technology for synthesizing the water reducing agent under low temperature conditions in the prior art, so that the application does not need to increase the investment in equipment such as heat sources, has the advantages of saving energy consumption, short synthesis time, economy and environmental protection; at the same time, the reaction conditions of the application are easy to control, the production equipment and production process are simple, and there is no "three wastes" discharge.

[0044] Optionally, when the water reducing agent contains a modifier, the preparation method of the water reducing agent specifically comprises the following steps:

[0045] Under normal temperature conditions, water, a six-carbon monomer and a functional monomer are mixed, the temperature of the mixed system is adjusted to 16-20℃, then 1 / 3 of the amount of a small monomer is added and mixed, and the temperature is controlled to be unchanged, to obtain component A;

[0046] The remaining 2 / 3 of the amount of the small monomer, a chain transfer agent and a slow-release monomer are mixed to obtain component B;

[0047] The reducing agent is diluted 8-10 times with water to obtain component C;

[0048] The components B and C are simultaneously added dropwise into the component A, the drop completion time of the component B is controlled to be 30-50 min, the drop completion time of the component C is controlled to be 60-80 min, after the drop of both is completed, the temperature is kept for 50-70 min, a modifier and a pH adjuster are added, stirring is performed for 20-40 min, an anti-caking agent is added and stirring is continued for 20-40 min, and then the water reducing agent is obtained through spray drying.

[0049] Preferably, the conditions for spray drying are that the inlet temperature is 140-160℃, the outlet temperature is 60-80℃, and the speed of the atomizer is 18000-20000r / min.

[0050] In a third aspect, the application provides the use of the above-mentioned water reducing agent in the field of building materials.

[0051] In summary, the technical scheme of the application has the following effects:

[0052] 1. The application provides a high-fluidity slow-release polycarboxylic acid water reducer suitable for gypsum-based self-leveling mortar. By selecting the preparation raw materials and their weight parts, and controlling the molecular structure and molecular weight of the six-carbon monomer, a high-fluidity slow-release polycarboxylic acid water reducer can be obtained, which can effectively improve the fluidity of the gypsum-based self-leveling mortar and reduce the flow loss of the gypsum-based self-leveling mortar.

[0053] 2. The application introduces a functional monomer with a sulfonic acid structure, a modifier with an ester group structure that can hydrolyze to release a carboxylic acid group with water-reducing effect under alkaline conditions, a silane structure, and a polyether structure into the water reducer, which can effectively improve the application performance of the water reducer in the gypsum-based self-leveling mortar, thereby improving the fluidity of the gypsum-based self-leveling mortar and reducing the flow loss of the gypsum-based self-leveling mortar.

[0054] 3. The application further optimizes the preparation process of the water reducer by selecting the addition sequence of the preparation raw materials, utilizing the synergistic effect between the raw materials, and the inlet and outlet temperatures of the spray drying, replacing the existing technology of synthesizing the water reducer under low temperature conditions, so that the application does not need to increase the investment in equipment such as heat source, has the advantages of saving energy consumption, short synthesis time, and economic environmental protection.

[0055] 4. The water reducer powder synthesized under non-heating conditions and by spray drying has significantly higher fluidity and lower flow loss than the ordinary polycarboxylic acid water reducer on the market in the gypsum-based self-leveling mortar, and can significantly improve the adaptability to different gypsums.

[0056] 5. The application further optimizes the preparation process of the water reducer, which can replace the existing technology of synthesizing the water reducer under low temperature conditions, so that the application does not need to increase the investment in equipment such as heat source, has the advantages of saving energy consumption, short synthesis time, and economic environmental protection; at the same time, the reaction conditions of the application are easy to control, the production equipment and process are simple, and there is no "three wastes" discharge. DETAILED DESCRIPTION

[0057] In a first aspect, the application provides a water reducer, which comprises the following components in parts by weight: 30-35 parts of a six-carbon monomer, 2-4 parts of a small monomer, 2-3 parts of a slow-release monomer, 1-2 parts of a functional monomer, 0.5-1 part of a chain transfer agent, 0.1-0.5 part of a reducing agent, 0.1-0.5 part of an oxidizing agent, 1-3 parts of a pH adjuster, 1-3 parts of an anti-caking agent, and 50-60 parts of soft water.

[0058] The small monomer is selected from one or more of acrylic acid and methacrylic acid.

[0059] The slow-release monomer is selected from one or more of hydroxypropyl acrylate and hydroxyethyl acrylate.

[0060] The functional monomer is selected from one or more of 2-acrylamido-2-methylpropane sulfonic acid, sodium methacrylate sulfonate, and sodium allyl sulfonate;

[0061] The six-carbon monomer is selected from one or more of hydroxyethyl-3-butenyl ether, hydroxypropyl allyl ether, diethylene glycol monovinyl ether, isopentenyl alcohol polyoxyethylene ether, and 4-hydroxybutyl vinyl ether.

[0062] Specifically, the six-carbon monomer is isopentenyl alcohol polyoxyethylene ether with a molecular weight of 3000-5000.

[0063] Further, the functional monomer is sodium methacrylate sulfonate and sodium allyl sulfonate in a weight ratio of (1-1.3):(0.2-0.5).

[0064] Meanwhile, the oxidizing agent is selected from one or more of hydrogen peroxide, potassium persulfate, and ammonium persulfate.

[0065] The pH regulator is selected from one or more of sodium bicarbonate, sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

[0066] The chain transfer agent is selected from one or more of mercaptopropionic acid and mercaptoethanol.

[0067] The reducing agent is selected from one or more of ascorbic acid, sodium hyposulfite formaldehyde, and E51 (epoxy resin).

[0068] The anti-caking agent is selected from one or more of calcined kaolin, fumed silica, and heavy calcium powder.

[0069] Further, the oxidizing agent is hydrogen peroxide; and the pH regulator is sodium hydroxide.

[0070] In addition, the water reducing agent further includes a modifier in an amount of 0.01-0.1 parts; the modifier includes a silane defoaming agent and a polyether air entraining agent in a weight ratio of (0.5-1.5):(0.5-1.5).

[0071] In a second aspect, the application provides a preparation method of the water reducing agent, specifically including the following steps:

[0072] Under normal temperature conditions, water, the six-carbon monomer, and the functional monomer are mixed, the temperature of the mixed system is adjusted to 16-20°C, then the oxidizing agent and 1 / 3 of the amount of the small monomer are mixed, and the temperature is controlled to be unchanged to obtain component A;

[0073] The remaining 2 / 3 of the amount of the small monomer, the chain transfer agent, and the slow-release monomer are mixed to obtain component B;

[0074] The reducing agent is diluted 8-10 times with water to obtain component C;

[0075] The B component and the C component are simultaneously added dropwise into the A component, the drop completion time of the B component is controlled to be 30-50 min, the drop completion time of the C component is controlled to be 60-80 min; after both are dropped, 1 h of heat preservation is performed, a pH regulator is added, 20-40 min of stirring is performed, an anti-caking agent is added, and 20-40 min of continuous stirring is performed;

[0076] The water-reducing agent can be obtained through spray drying.

[0077] Optionally, when the water-reducing agent contains a modifier, the preparation method of the water-reducing agent specifically comprises the following steps:

[0078] Under normal temperature conditions, water, a six-carbon monomer and a functional monomer are mixed, the temperature of the mixed system is adjusted to be 16-20 ℃, then 1 / 3 of the amount of a small monomer is mixed with an oxidizing agent, the temperature is controlled to be unchanged, and an A component is obtained;

[0079] 2 / 3 of the amount of a small monomer, a chain transfer agent and a slow-release monomer are mixed to obtain a B component;

[0080] The reducing agent is diluted 8-10 times with water to obtain a C component;

[0081] The B component and the C component are simultaneously added dropwise into the A component, the drop completion time of the B component is controlled to be 30-50 min, the drop completion time of the C component is controlled to be 60-80 min; after both are dropped, 50-70 min of heat preservation is performed, a modifier and a pH regulator are added, 20-40 min of stirring is performed, an anti-caking agent is added, and 20-40 min of continuous stirring is performed;

[0082] The water-reducing agent can be obtained through spray drying.

[0083] The spray drying conditions are as follows: an inlet temperature of 140-160 ℃, an outlet temperature of 60-80 ℃ and an atomizer rotating speed of 18000-20000 r / min.

[0084] In a third aspect, the application provides application of the water-reducing agent in the field of building materials.

[0085] The application will be further described in detail below in combination with examples, comparative examples and performance detection tests, and the examples cannot be understood as limiting the scope of the application.

[0086] Unless otherwise specified, the examples are carried out under conventional conditions or conditions recommended by manufacturers. The reagents used are conventional products that can be obtained through commercial channels.

[0087] Examples

[0088] Examples 1-5

[0089] Examples 1-5 respectively provide a water-reducing agent.

[0090] The difference between the above examples is the amount of each raw material, as shown in Table 1.

[0091] The preparation method of the water reducing agent in the above examples is as follows:

[0092] S1: Under normal temperature conditions, mix water, six-carbon monomers, and functional monomers, adjust the temperature of the mixed system to 16-20°C, then add an oxidizing agent and 1 / 3 of the amount of small monomers for mixing, control the temperature, and obtain component A;

[0093] Mix the remaining 2 / 3 of the amount of small monomers, chain transfer agents, and slow-release monomers to obtain component B;

[0094] Dilute the reducing agent with water by 10 times to obtain component C;

[0095] S2: Add components B and C to component A at the same time, control the drop completion time of component B to be 40-50 min, and control the drop completion time of component C to be 70-80 min; after both are dropped, keep warm for 60 min, add a pH adjuster, stir for 30 min, add an anti-caking agent and continue stirring for 30 min, and obtain a mixed slurry;

[0096] S3: Spray dry the mixed slurry under the conditions of an inlet temperature of 150°C, an outlet temperature of 70°C, and a centrifugal dryer atomizer speed of 20,000 r / min, and a water reducing agent is obtained.

[0097] Table 1 Amount of each raw material in Examples 1-5

[0098]

[0099]

[0100] Example 6

[0101] The present example provides a water reducing agent.

[0102] The difference between the present example and Example 1 is that the molecular weight of iso-pentenyl alcohol polyoxyethylene ether is 3000, and the remaining raw material components and the preparation method of the water reducing agent are the same as those of Example 1.

[0103] Example 7

[0104] The present example provides a water reducing agent.

[0105] The difference between the present example and Example 1 is that the molecular weight of iso-pentenyl alcohol polyoxyethylene ether is 4000, and the remaining raw material components and the preparation method of the water reducing agent are the same as those of Example 1.

[0106] Example 8

[0107] The present embodiment provides a water reducing agent.

[0108] The present embodiment differs from Example 1 in that the molecular weight of isoamylene polyoxyethylene ether is 6000, and the remaining raw material components and the preparation method of the water reducing agent are the same as those of Example 1.

[0109] Example 9

[0110] The present embodiment provides a water reducing agent.

[0111] The present embodiment differs from Example 1 in that the functional monomer is sodium allylsulfonate, and the remaining raw material components and the preparation method of the water reducing agent are the same as those of Example 1.

[0112] Example 10

[0113] The present embodiment provides a water reducing agent.

[0114] The present embodiment differs from Example 1 in that the functional monomer is 2-acrylamido-2-methylpropanesulfonic acid, and the remaining raw material components and the preparation method of the water reducing agent are the same as those of Example 1.

[0115] Example 11

[0116] The present embodiment provides a water reducing agent.

[0117] The present embodiment differs from Example 1 in that the functional monomers are sodium methallylsulfonate and sodium allylsulfonate at a weight ratio of 1.3:0.2, and the remaining raw material components and the preparation method of the water reducing agent are the same as those of Example 1.

[0118] Example 12

[0119] The present embodiment provides a water reducing agent.

[0120] The present embodiment differs from Example 1 in that the functional monomers are sodium methallylsulfonate and sodium allylsulfonate at a weight ratio of 1:0.5, and the remaining raw material components and the preparation method of the water reducing agent are the same as those of Example 1.

[0121] Example 13

[0122] The present embodiment provides a water reducing agent.

[0123] The present embodiment differs from Example 1 in that the functional monomers are sodium methallylsulfonate and sodium allylsulfonate at a weight ratio of 1.3:0.1, and the remaining raw material components and the preparation method of the water reducing agent are the same as those of Example 1.

[0124] Example 14

[0125] The embodiment provides a water reducing agent.

[0126] The embodiment is different from the embodiment 1 in that the functional monomer is sodium methacrylate sulfonate and sodium allyl sulfonate with a weight ratio of 1:0.6, and the preparation method of the remaining raw material components and the water reducing agent is the same as that in the embodiment 1.

[0127] Embodiment 15

[0128] The embodiment provides a water reducing agent.

[0129] The embodiment is different from the embodiment 1 in that the water reducing agent further comprises 0.05 parts of a modifier; the modifier is a silane defoaming agent and a polyether air entraining agent with a weight ratio of 1:1, and the remaining raw material components are the same as those in the embodiment 1.

[0130] The preparation method of the water reducing agent in the embodiment is as follows:

[0131] S1: under normal temperature conditions, water, a six-carbon monomer and a functional monomer are mixed, the temperature of the mixed system is adjusted to 16-20 DEG C, then 1 / 3 of the amount of a small monomer is added and mixed, and the temperature is controlled to be unchanged, to obtain an A component;

[0132] The remaining 2 / 3 of the amount of the small monomer, a chain transfer agent and a slow-release monomer are mixed to obtain a B component;

[0133] The reducing agent is diluted 10 times with water to obtain a C component;

[0134] S2: the B component and the C component are simultaneously added dropwise into the A component, the dropwise adding time of the B component is controlled to be 40-50 min, the dropwise adding time of the C component is controlled to be 70-80 min; after the dropwise adding of both is completed, the mixture is preserved for 60 min, a modifier and a pH regulator are added, the mixture is stirred for 30 min, an anti-caking agent is added and the mixture is continuously stirred for 30 min, to obtain a mixed slurry;

[0135] S3: the mixed slurry is subjected to spray drying under the conditions that the inlet temperature is 150 DEG C, the outlet temperature is 70 DEG C and the rotation speed of a centrifugal drying atomizer is 20000 r / min, to obtain the water reducing agent.

[0136] Embodiment 16

[0137] The embodiment provides a water reducing agent.

[0138] The embodiment is different from the embodiment 15 in that the modifier is a silane defoaming agent and a polyether air entraining agent with a weight ratio of 1.5:0.5, and the preparation method of the remaining raw material components and the water reducing agent is the same as that in the embodiment 15.

[0139] Embodiment 17

[0140] The embodiment provides a water reducing agent.

[0141] The embodiment is different from the embodiment 15 in that a modifier is a silane defoaming agent and a polyether air entraining agent in a weight ratio of 0.5:1.5, and the preparation methods of the remaining raw material components and the water reducing agent are the same as those in the embodiment 15.

[0142] Embodiment 18

[0143] The embodiment provides a water reducing agent.

[0144] The embodiment is different from the embodiment 15 in that a modifier is a silane defoaming agent and a polyether air entraining agent in a weight ratio of 1:0.4, and the preparation methods of the remaining raw material components and the water reducing agent are the same as those in the embodiment 15.

[0145] Embodiment 19

[0146] The embodiment provides a water reducing agent.

[0147] The embodiment is different from the embodiment 15 in that a modifier is a silane defoaming agent and a polyether air entraining agent in a weight ratio of 0.4:1, and the preparation methods of the remaining raw material components and the water reducing agent are the same as those in the embodiment 15.

[0148] Embodiment 20

[0149] The embodiment provides a water reducing agent.

[0150] The embodiment is different from the embodiment 1 in that the preparation method of the water reducing agent is different, and the raw material components in the water reducing agent are the same as those in the embodiment 1.

[0151] The preparation method of the water reducing agent in the embodiment is as follows:

[0152] S1: under normal temperature conditions, water, a six-carbon monomer and a functional monomer are mixed, the temperature of the mixed system is adjusted to 16-20 DEG C, then 1 / 3 of the dosage of a small monomer is mixed into an oxidizing agent, the temperature is controlled to be unchanged, and an A component is obtained;

[0153] The remaining 2 / 3 of the dosage of the small monomer, a chain transfer agent and a slow-release monomer are mixed to obtain a B component;

[0154] The reducing agent is diluted 10 times with water to obtain a C component;

[0155] S2: the B component and the C component are simultaneously added dropwise into the A component, the dropwise adding time of the B component is controlled to be 30-40 min, the dropwise adding time of the C component is controlled to be 60-70 min, after the dropwise adding of both is completed, the temperature is kept for 60 min, a pH regulator is added, stirring is performed for 30 min, an anti-caking agent is continuously added and stirring is continuously performed for 30 min, and a mixed slurry is obtained;

[0156] S3: The mixed slurry is spray dried under the conditions of an inlet temperature of 150°C, an outlet temperature of 70°C, and a centrifugal drying atomizer rotating speed of 20000r / min, to obtain the water reducing agent.

[0157] Comparative Examples 1-3

[0158] The above comparative examples each provide a water reducing agent.

[0159] The above comparative examples differ from Example 1 in that the amounts of the raw materials added to the water reducing agent are different, as shown in Table 2; and the preparation method of the water reducing agent in the above comparative examples is the same as that of Example 1.

[0160] Table 2: Amounts of raw materials in Comparative Examples 1-3

[0161]

[0162]

[0163] Comparative Example 4

[0164] The above comparative example provides a water reducing agent.

[0165] The above comparative example differs from Example 1 in that the preparation method of the water reducing agent is different: the order of addition of the raw materials is different; and the raw material components of the water reducing agent are the same as those of Example 1.

[0166] The preparation method of the water reducing agent in the above comparative example is as follows:

[0167] S1: Under normal temperature conditions, water, a six-carbon monomer, and a functional monomer are mixed, the temperature of the mixed system is adjusted to 16-20°C, and then a small monomer of an oxidizing agent is added for mixing, with the temperature being controlled to remain unchanged, to obtain component A;

[0168] A small monomer, a chain transfer agent, and a slow-release monomer are mixed to obtain component B;

[0169] The reducing agent is diluted 10 times with water to obtain component C;

[0170] S2: Components B and C are simultaneously added dropwise to component A, the dropwise addition of component B is controlled to be completed in 40-50min, and the dropwise addition of component C is controlled to be completed in 70-80min; after both are added dropwise, the mixture is kept at temperature for 60min, a pH adjuster is added, the mixture is stirred for 30min, an anti-caking agent is added, and the mixture is stirred for another 30min, to obtain a mixed slurry;

[0171] S3: The mixed slurry is spray dried under the conditions of an inlet temperature of 150°C, an outlet temperature of 70°C, and a centrifugal drying atomizer rotating speed of 20000r / min, to obtain the water reducing agent.

[0172] Comparative Example 5

[0173] The present comparative example provides a water reducing agent.

[0174] The present comparative example differs from Example 1 in that the preparation method of the water reducing agent is different: in step S1, the system temperature is not controlled to be 16-20°C; and the raw material components of the water reducing agent are the same as those of Example 1.

[0175] The preparation method of the water reducing agent in the present comparative example is as follows:

[0176] S1: Under normal temperature conditions, water, a six-carbon monomer, and a functional monomer are mixed, and then a 1 / 3 amount of a small monomer is added to the mixture, and the temperature is controlled to be unchanged, to obtain component A;

[0177] The remaining 2 / 3 amount of the small monomer, a chain transfer agent, and a slow-release monomer are mixed to obtain component B;

[0178] The reducing agent is diluted 10 times with water to obtain component C;

[0179] S2: Components B and C are simultaneously added dropwise to component A, the dropwise addition of component B is controlled to be completed in 40-50 min, and the dropwise addition of component C is controlled to be completed in 70-80 min; after the dropwise addition of both components is completed, the mixture is kept at a constant temperature for 60 min, a modifier and a pH adjuster are added, the mixture is stirred for 30 min, an anti-caking agent is added, and the mixture is further stirred for 30 min to obtain a mixed slurry;

[0180] S3: The mixed slurry is subjected to spray drying under the conditions of an inlet temperature of 150°C, an outlet temperature of 70°C, and a centrifugal dryer atomizer rotating speed of 20,000 r / min, to obtain the water reducing agent.

[0181] Performance test

[0182] According to the relevant provisions of JC / T1023 2021 “Gypsum-based self-leveling mortar”, the gypsum self-leveling mortar prepared using Guizhou phosphogypsum is shown in Table 3, and then the water reducing agent is added at a dosage of 2.5 wt‰; the initial fluidity, 30 min fluidity, and 60 min fluidity of the gypsum are tested. The market gypsum-based polycarboxylic acid water reducing agent PC-city is used as a comparison, and the polycarboxylic acid water reducing agent PC-0 is used as a comparison for cement-based materials.

[0183] At the same time, according to the same detection method, the water reducing agent is applied to the preparation of the gypsum self-leveling mortar using Shandong desulfurization gypsum at a dosage of 2 wt‰, and the initial fluidity, 30 min fluidity, and 60 min fluidity of the gypsum are tested.

[0184] Table 3 Formulation of gypsum self-leveling mortar prepared using Guizhou phosphogypsum

[0185] Guizhou phosphogypsum powder P.O cement Suspension agent HPMC (20,000) Defoaming agent Gypsum retarder Water addition amount (ml) 950 50 0.4 0.3 1 0.2 460

[0186] Table 4 Shandong phosphogypsum prepared gypsum self-leveling mortar formula

[0187]

[0188] The test results are shown in Table 5.

[0189] Table 5 Test results of the fluidity and fluidity retention of the gypsum-based self-leveling mortar

[0190]

[0191]

[0192] In combination with Table 5, by comparing the test results of Comparative Examples 1-20 and Comparative Examples 1-5 and PC-city, PC-0, it can be seen that the water reducing agent prepared by the present application using 30-35 parts of the six-carbon monomer, 2-4 parts of the small monomer, 2-3 parts of the slow-release monomer, 1-2 parts of the functional monomer, 0.5-1 part of the chain transfer agent, 0.1-0.5 part of the reducing agent, 0.1-0.5 part of the oxidizing agent, 1-3 parts of the pH regulator, 1-3 parts of the anti-caking agent, and 50-60 parts of soft water can be applied to the gypsum-based self-leveling mortar, which can significantly improve the fluidity of the gypsum-based self-leveling mortar, while the flow loss is small, and the fluidity retention rate of the gypsum-based self-leveling mortar is good.

[0193] By comparing the test results of Comparative Examples 1-5 and Comparative Examples 1-3, the water reducing agent obtained by screening the weight parts of each raw material component can be applied to the gypsum-based self-leveling mortar, which can significantly improve the fluidity and fluidity retention rate of the gypsum-based self-leveling mortar.

[0194] By comparing the test results of Comparative Example 1 and Examples 6-8, when the molecular weight of prenol polyoxyethylene ether is controlled to be 3000-5000, the fluidity of the gypsum-based self-leveling mortar can be further improved, and the flow loss of the gypsum-based self-leveling mortar can be reduced.

[0195] By comparing the test results of Comparative Example 1 and Examples 9-14, compared with selecting sodium allyl sulfonate, 2-acrylamido-2-methylpropane sulfonic acid, and sodium allyl sulfonate as the functional monomer alone, the present application selects sodium methallyl sulfonate and sodium allyl sulfonate as the functional monomer, and controls the weight ratio of the two to be (1-1.3):(0.2-0.5), which can further improve the fluidity of the gypsum-based self-leveling mortar and reduce the flow loss of the gypsum-based self-leveling mortar.

[0196] By comparing the test results of comparative example 1 and examples 15-19, when the silane defoaming agent and the polyether air entraining agent are added in the water reducing agent as the modifier, the fluidity of the gypsum-based self-leveling mortar can be further improved, and the flow loss of the gypsum-based self-leveling mortar can be reduced.

[0197] By comparing the test results of comparative example 1 and example 20, when the dropping time of the B component is controlled to be 30-50 min and the dropping time of the C component is controlled to be 60-80 min in the preparation method of the water reducing agent, the water reducing agent with good application performance can be obtained while the reaction time is reduced and the cost is reduced.

[0198] Although the present application has been described in detail with general description and specific embodiments above, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application claimed.

Claims

1. A water-reducing agent, characterized in that, It includes the following components by weight: 30-35 parts of hexacarbon monomer, 2-4 parts of small monomer, 2-3 parts of slow-release monomer, 1-2 parts of functional monomer, 0.5-1 part of chain transfer agent, 0.1-0.5 parts of reducing agent, 0.1-0.5 parts of oxidizing agent, 1-3 parts of pH adjuster, 1-3 parts of anti-caking agent, 50-60 parts of soft water, and 0.01-0.1 parts of modifier; The six-carbon monomer is isopentenyl alcohol polyoxyethylene ether with a molecular weight of 5000; The small monomer is selected from one or more of acrylic acid and methacrylic acid; The sustained-release monomer is selected from one or more of hydroxypropyl acrylate and hydroxyethyl acrylate; The functional monomer is sodium methacrylate sulfonate and sodium allyl sulfonate in a weight ratio of 1.3:0.1 or sodium methacrylate sulfonate and sodium allyl sulfonate in a weight ratio of 1:0.

6. The chain transfer agent is selected from one or more of mercaptopropionic acid and mercaptoethanol; The reducing agent is selected from one or more of ascorbic acid, sodium formaldehyde sulfoxylate, and E51; The oxidant is selected from one or more of hydrogen peroxide, potassium persulfate, and ammonium persulfate; The pH adjuster is selected from one or more of sodium bicarbonate, sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. The anti-caking agent is selected from one or more of calcined kaolin, fumed silica, and heavy calcium carbonate powder; The modifier comprises a silane defoamer and a polyether air-entraining agent in a weight ratio of (0.5-1.5):(0.5-1.5); The water-reducing agent is prepared by the following steps: At room temperature, water, a six-carbon monomer, and a functional monomer are mixed, and the temperature of the mixture is adjusted to 16-20℃. Then, an oxidant and 1 / 3 of the amount of the small monomer are added and mixed, while keeping the temperature constant, to obtain component A. The remaining 2 / 3 of the small monomer, chain transfer agent, and sustained-release monomer are mixed to obtain component B; Dilute the reducing agent with water 8-10 times to obtain component C; Add components B and C dropwise to component A simultaneously, controlling the dropwise addition time of component B to 30-50 min and the dropwise addition time of component C to 60-80 min; after both components have been added, keep warm for 1 h, add modifier and pH adjuster, stir for 20-40 min, add anti-caking agent and continue stirring for 20-40 min; The water-reducing agent can be obtained by spray drying.

2. The method for preparing the water-reducing agent as described in claim 1, characterized in that, It is prepared by the following steps: At room temperature, water, a six-carbon monomer, and a functional monomer are mixed, and the temperature of the mixture is adjusted to 16-20℃. Then, an oxidant and 1 / 3 of the amount of the small monomer are added and mixed, while keeping the temperature constant, to obtain component A. The remaining 2 / 3 of the small monomer, chain transfer agent, and sustained-release monomer are mixed to obtain component B; Dilute the reducing agent with water 8-10 times to obtain component C; Add components B and C dropwise to component A simultaneously, controlling the dropwise addition time of component B to 30-50 min and the dropwise addition time of component C to 60-80 min; after both components have been added, keep warm for 1 h, add modifier and pH adjuster, stir for 20-40 min, add anti-caking agent and continue stirring for 20-40 min; The water-reducing agent can be obtained by spray drying; the spray drying conditions are: inlet temperature 140-160℃, outlet temperature 60-80℃, and atomizer speed 18000-20000r / min.

3. The application of the water-reducing agent as described in claim 1 in the field of building materials.

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