Normal-temperature synthesis method of multi-element-initiated slow-release slump-retaining polycarboxylic acid water reducer
阅读说明：本技术 一种多元引发缓释保坍型聚羧酸减水剂常温合成方法 (Normal-temperature synthesis method of multi-element-initiated slow-release slump-retaining polycarboxylic acid water reducer ) 是由 王远福 陈杰 方世昌 田应兵 于 2020-07-31 设计创作，主要内容包括：本申请涉及混凝土外加剂技术领域,具体公开了一种多元引发缓释保坍型聚羧酸减水剂常温合成方法,将包括不饱和聚氧乙烯醚、丙烯酸、缓释单体、链转移剂和自来水的底料投入反应釜中,搅拌至溶解,底料溶解后投入第一氧化剂溶液,搅拌至完全溶解后同时滴加事先配置好的A料和B料,滴加时间为2.5-3.5小时,在滴加反应至1-1.5小时时投入第二引发剂溶液。A、B料同时滴完后继续保温反应1-2小时,加自来水稀释至所需浓度即得。本专利的目的在于解决现有的聚羧酸减水剂无法在常温条件下合成导致的生产成本高的问题。(The application relates to the technical field of concrete admixtures, and particularly discloses a normal-temperature synthesis method of a multi-initiation slow-release slump-retaining polycarboxylic acid water reducer, which comprises the steps of putting a base material comprising unsaturated polyoxyethylene ether, acrylic acid, a slow-release monomer, a chain transfer agent and tap water into a reaction kettle, stirring until the base material is dissolved, putting a first oxidant solution after the base material is dissolved, stirring until the base material is completely dissolved, simultaneously dropwise adding a material A and a material B which are prepared in advance, wherein the dropwise adding time is 2.5-3.5 hours, and putting a second initiator solution when the dropwise adding reaction is 1-1.5 hours. A. And (4) continuing the heat preservation reaction for 1-2 hours after the material B is dripped simultaneously, and adding tap water to dilute to the required concentration to obtain the material B. The purpose of this patent is to solve the problem that current polycarboxylate water reducing agent can't synthesize the high manufacturing cost who leads to under the normal atmospheric temperature condition.)
1. A normal-temperature synthesis method of a multi-element initiated slow-release slump-retaining polycarboxylate superplasticizer is characterized by comprising the following steps: adding a bottom material comprising unsaturated polyoxyethylene ether, acrylic acid, a slow-release monomer, a chain transfer agent and tap water into a reaction kettle, stirring until the bottom material is dissolved, adding a first oxidant solution after the bottom material is dissolved, stirring until the bottom material is completely dissolved, simultaneously dropwise adding a material A and a material B which are prepared in advance, wherein the dropwise adding time is 2.5-3.5 hours, and adding a second initiator solution when the dropwise adding reaction is 1-1.5 hours; A. after the material B is dripped simultaneously, the reaction is continued for 1 to 2 hours under heat preservation, and tap water is added for dilution to the required concentration to obtain the material B;
the material A comprises unsaturated carboxylic acid, a slow release monomer and tap water;
the material B comprises a chain transfer agent, a reducing agent, a catalyst and tap water.
2. The normal-temperature synthesis method of the multi-element initiation slow-release slump-retaining type polycarboxylate water reducer as claimed in claim 1, wherein the method comprises the following steps: the unsaturated polyoxyethylene ether is methyl allyl alcohol polyoxyethylene ether with the molecular weight of 1000-3000.
3. The normal-temperature synthesis method of the multi-element initiation slow-release slump-retaining polycarboxylate superplasticizer according to claim 2, characterized by comprising the following steps: the oxidant solution is an oxidant aqueous solution, the oxidant is selected from one or more of hydrogen peroxide, tert-butyl hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, potassium permanganate and potassium dichromate, the using amount of the oxidant accounts for 0.7-1.8% of the mass of the unsaturated polyoxyethylene ether, the mass of the first oxidant accounts for 50-70% of the total amount of the oxidant, and the using amount of the second initiator accounts for 50-30% of the total amount of the oxidant.
4. The normal-temperature synthesis method of the multi-element initiation slow-release slump-retaining polycarboxylate superplasticizer according to claim 3, characterized by comprising the following steps: the unsaturated carboxylic acid is selected from one or more of acrylic acid, methacrylic acid, maleic acid and itaconic acid.
5. The normal-temperature synthesis method of the multi-element initiation slow-release slump-retaining type polycarboxylate water reducer as claimed in claim 4, wherein the method comprises the following steps: the slow release monomer is one or more than two of hydroxyethyl acrylate, hydroxypropyl acrylate and ethylene glycol maleate.
6. The normal-temperature synthesis method of the multi-element initiation slow-release slump-retaining polycarboxylate superplasticizer according to claim 5, characterized by comprising the following steps: the chain transfer agent is one or more than two of thioglycolic acid, mercaptopropionic acid, mercaptoethanol and sodium hypophosphite.
7. The normal-temperature synthesis method of the multi-element initiation slow-release slump-retaining type polycarboxylate water reducer as claimed in claim 1, wherein the method comprises the following steps: the reducing agent is one or more than two of vitamin C, sodium formaldehyde sulfoxylate, sodium bisulfite, ferrous sulfate and E51.
Technical Field
The invention relates to the technical field of concrete admixtures, in particular to a normal-temperature synthesis method of a multi-element initiation slow-release slump-retaining type polycarboxylic acid water reducing agent.
Background
The polycarboxylic acid water reducing agent has high water reducing rate and slump retaining capacity, and is more and more widely applied to the engineering of high-speed rail and highway buildings in China. At present, most of polycarboxylic acid water reducing agents are synthesized by heating a system and promoting an initiator to decompose to generate free radicals through heating, and the process has high energy consumption and high equipment maintenance cost. The main methods for synthesizing the polycarboxylic acid water reducing agent by heating comprise 3 methods: copolymerization synthesis, functionalization method, in-situ polymerization and grafting. The main method for normal-temperature synthesis is copolymerization synthesis, free radicals are generated through redox reaction, and the selection range of the relative polymerizable monomer types of the polycarboxylate superplasticizer synthesized at normal temperature is far smaller than the selection of raw materials for synthesizing the polycarboxylate superplasticizer by heating.
At present, the production process of the polycarboxylic acid water reducing agent is generally synthesized by free radical reaction at the temperature of 40-90 ℃. The reaction temperature is reduced, and the production cost is greatly reduced even if the synthesis is carried out by a pyrogen-free method.
In addition, the water quality requirement in the production of the polycarboxylic acid water reducing agent is high, treated softened water or deionized water is generally used, and if the polycarboxylic acid water reducing agent can be synthesized by tap water, the production is greatly simplified, and the cost is further reduced.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a normal-temperature synthesis method of a multi-element initiation slow-release slump-retaining polycarboxylate water reducer, and solves the problem of high production cost caused by the fact that the conventional polycarboxylate water reducer cannot be synthesized at normal temperature.
In order to solve the problems, the technical scheme adopted by the invention is as follows: a normal-temperature synthesis method of a multi-initiation slow-release slump-retaining polycarboxylate water reducer comprises the steps of putting a bottom material comprising unsaturated polyoxyethylene ether, acrylic acid, a slow-release monomer, a chain transfer agent and tap water into a reaction kettle, stirring until the bottom material is dissolved, putting a first oxidant solution into the reaction kettle, stirring until the bottom material is completely dissolved, simultaneously dropwise adding a material A and a material B which are prepared in advance, wherein the dropwise adding time is 2.5-3.5 hours, and putting a second initiator solution into the reaction kettle when the dropwise adding reaction is carried out for 1-1.5 hours; A. after the material B is dripped simultaneously, the reaction is continued for 1 to 2 hours under heat preservation, and tap water is added for dilution to the required concentration to obtain the material B;
the material A comprises unsaturated carboxylic acid, a slow release monomer and tap water;
the material B comprises a chain transfer agent, a reducing agent, a catalyst and tap water.
Further, the unsaturated polyoxyethylene ether is methyl allyl alcohol polyoxyethylene ether with the molecular weight of 1000-3000.
Further, the oxidant solution is an oxidant aqueous solution, the oxidant is selected from one or more of hydrogen peroxide, tert-butyl hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, potassium permanganate and potassium dichromate, the amount of the oxidant accounts for 0.7-1.8% of the mass of the unsaturated polyoxyethylene ether, the mass of the first oxidant accounts for 50-70% of the total amount of the oxidant, and the amount of the second initiator accounts for 50-30% of the total amount of the oxidant.
Further, the unsaturated carboxylic acid is selected from one or more of acrylic acid, methacrylic acid, maleic acid and itaconic acid.
Further, the slow release monomer is selected from one or more of hydroxyethyl acrylate, hydroxypropyl acrylate and ethylene glycol maleate.
Further, the chain transfer agent is selected from one or more than two of thioglycolic acid, mercaptopropionic acid, mercaptoethanol and sodium hypophosphite.
Furthermore, the reducing agent is selected from one or more than two of vitamin C, sodium formaldehyde sulfoxylate, sodium bisulfite, ferrous sulfate and E51, and E51 is a code number of a reducing agent commonly used in the field.
Further, the material A is dripped or the material B is dripped simultaneously by adopting the following equipment: the dripping equipment comprises a rack and a box body, wherein a motor is fixed at the part of the rack above the box body, an output shaft of the motor is arranged downwards vertically, a rotating rod is fixed on the output shaft of the motor, the lower end of the rotating rod extends to the lower part in the box body, and a stirring paddle is fixed at the lower end of the rotating rod; a first gear is fixed on the part of the rotating rod above the box body, a second gear is meshed on one side of the first gear, a third gear is meshed on one side of the second gear, the reduction ratio of the first gear to the second gear is 1:1.5-2, the reduction ratio of the second gear to the third gear is 1:50-100, the third gear is coaxially and fixedly connected with a first cam and a second cam, the first gear and the second gear are arranged along the horizontal direction, the first cam and the second cam are both half cams, and the first cam and the second cam are in central symmetry about the axis of the third gear; a cylinder body arranged along the horizontal direction is fixed on the rack, a piston is connected in the cylinder body in a sliding and sealing manner, a piston rod arranged along the horizontal direction is fixed on one side of the piston close to the third gear, the piston rod can be attached to the outer side walls of the first cam and the second cam, one end of the cylinder body close to the piston rod is provided with an opening, a spring is arranged in the cylinder body, one end of the spring is fixed on one side of the cylinder body close to the piston rod, the other end of the spring is fixed on the piston, a magnet is arranged on the side wall of the cylinder body close; one end of the cylinder body, which is far away from the spring, is provided with a one-way inlet valve, and one end of the lower end of the cylinder body, which is far away from the spring, is provided with a one-way outlet valve, and the one-way outlet valve is positioned right above the box body; a water cylinder is fixed on the frame, a sliding cylinder for storing a solution to be dripped is connected in the water cylinder in a sliding manner, the sliding cylinder can slide up and down along the water cylinder, the one-way inlet valve sucks the solution in the sliding cylinder through a suction pipe, and the suction pipe is a hard pipe; the number of the cylinder bodies is set to be 2, the cylinder bodies are connected in series on the piston rod, the number of the water cylinders is also set to be 2 correspondingly, and the water cylinders correspond to the cylinder bodies one to one.
The motor drives the rotating rod to rotate, and the rotating rod drives the stirring paddle to stir the interior of the box body; meanwhile, the rotating rod drives the first gear to rotate, the first gear drives the second gear to rotate, the second gear drives the third gear to rotate, and the third gear drives the first cam and the second cam to rotate.
Starting the electromagnet, wherein in an initial state, the piston rod is positioned at one end, far away from the first cam and the second cam, of the cylinder body, the far-axis point of the first cam is about to be separated from the piston rod, meanwhile, the electromagnet and the magnet attract each other to enable the piston to instantly and rapidly compress the spring and approach the magnet, negative pressure is generated in the cylinder body, and the cylinder body sucks the solution in the sliding cylinder through a suction pipe; meanwhile, the near-axis point of the second cam is just attached to the piston rod, the second cam rotates to enable the piston rod to push the piston to overcome the magnetic force of the electromagnet and slowly slide towards the direction far away from the first cam and the second cam, the solution is slowly discharged from the interior of the cylinder body and is dripped into the interior of the box body until the solution in the interior of the cylinder body is completely discharged, and at the moment, the far-axis point of the second cam is about to be separated from the piston rod; then, in the same way, the first cam pushes the piston to slide in the direction away from the first cam and the second cam, and the process is repeated. Utilize the electro-magnet to make the piston slide the imbibition to the direction that is close to first cam and second cam fast in the twinkling of an eye to utilize first cam and second cam to promote the piston in turn and slide the flowing back to the direction of keeping away from first cam and second cam, realize the imbibition in the twinkling of an eye of cylinder body and slowly dropwise add the solution that inhales to the box, realize the at uniform velocity dropwise add of solution.
Water is added into the water cylinder in advance, and the sliding cylinder gradually floats upwards under the buoyancy action of the water along with the reduction of the solution in the sliding cylinder, so that the lower end of the suction pipe is always submerged by the solution in the sliding cylinder.
According to the time length of the dripping, the solution is diluted to be integral multiple of the volume of the cylinder body, for example, when the reduction ratio of the first gear and the second gear is 1:2, the reduction ratio of the second gear and the third gear is 1:90, the dripping time length is 180min, and the rotating speed of the motor is 360r/min, the rotating speed of the first cam and the second cam is 2r/min, the cylinder body sucks liquid and discharges liquid 2 times per minute, the cylinder body discharges liquid 360 times in total, and the solution in the sliding cylinder needs to be diluted to be 360 times of the volume of the cylinder body.
A material and a material B are respectively contained in the sliding cylinders in the two water cylinders, and the two cylinder bodies are respectively used for absorbing the material A and the material B. The simultaneous dripping of the material A and the material B can be realized, and the dripping time of the material A and the dripping time of the material B are completely the same.
Furthermore, a marking line is arranged at the position where the suction pipe is submerged by the solution in the sliding cylinder. When the marking line floats above the surface of the solution, in order to prevent air from being sucked into the interior of the cylinder, water needs to be properly added to the interior of the water tank so that the marking line is submerged by the solution.
Furthermore, the periphery of the one-way outlet valve is sleeved with a flow guide pipe, and the lower end face of the flow guide pipe is oval. The solution is convenient to be dripped, and the waste caused by the suspension of the solution at the bottom of the cylinder body is avoided.
Furthermore, two ends of the suction pipe are connected through a quick connector. If only need stir, when need not to add solution, just make the cylinder body can't inhale the inside solution of slip cylinder through making quick-operation joint both ends separation, when needs carry out dropwise add solution, again with the quick-operation joint's on the corresponding straw both ends connect can to when dropwise add two kinds of solutions, the start time and the finish time of two kinds of solutions dropwise add respectively are relatively independent, needn't be identical completely, this equipment is applicable in other dropwise add reactions.
Furthermore, one end of the piston, which is close to the one-way outlet valve, is provided with a groove which is arranged along the vertical direction, a floating ball is connected in the groove in a sliding manner, an electromagnet switch which is arranged along the vertical direction is fixed at the bottom of the groove, when the electromagnet switch is pressed, the electromagnet is electrified, and when the electromagnet switch is loosened, the electromagnet is powered off; be provided with on the cylinder body and press the valve, the case of pressing the valve is arranged along the horizontal direction, and the case of pressing the valve is pressed when the case of pressing the valve and is opened, when the case of pressing the valve is loosened, presses the valve and closes, when the piston moves to the one end that is close to one-way outlet valve, the piston can be pressed the case of pressing the valve and the recess inside communicates with pressing the valve.
When liquid is in the cylinder body, the floating ball floats upwards under the buoyancy action of the liquid, the electromagnet switch is released, and the electromagnet is powered off; when the piston moves to one end close to the one-way outlet valve, the piston presses the valve core of the pressing valve, the interior of the groove is communicated with the pressing valve, liquid in the groove is discharged from the pressing valve, the floating ball moves downwards under the action of gravity and presses the electromagnet switch, and the electromagnet is electrified to enable the piston to move towards one end far away from the one-way outlet valve instantly. The electromagnet does not need to be electrified for a long time, so that the energy can be saved, and the service life of the electromagnet can be prolonged.
The beneficial effect that this scheme produced is:
(1) compared with the prior art, the slow-release slump-retaining polycarboxylic acid water reducing agent is mostly carried out at a higher temperature, a reaction kettle needs to be heated in the reaction process, the slow-release slump-retaining polycarboxylic acid water reducing agent can be synthesized at a low temperature and a normal temperature (0-40' C) by adopting a multi-element redox initiation system, the reaction kettle does not need to be heated, and the process is simple and energy-saving.
(2) Compared with the existing multi-element initiation synthesis technology, the invention innovatively introduces the retarding monomer, so that the polycarboxylate superplasticizer has good initial water reducing performance and excellent slump retaining performance.
(3) Compared with the existing low-temperature synthesized slow-release slump-retaining polycarboxylic acid water reducing agent technology, the method has the advantages that the reaction monomer cannot completely react at the later stage due to the consumption of the initiator when the reducing agent is added at one time, and the monomer conversion rate is low. According to the activity of different initiators, different oxidants are added in different periods of time according to the temperature of different periods of reaction, so that a multi-element initiation system is formed, the reaction is more complete, and the performance of the slow-release slump-retaining water reducer is greatly improved.
Drawings
Fig. 1 is an overall structural view.
Fig. 2 is a top view of the first cam and the second cam.
Fig. 3 is an enlarged view of a portion a in fig. 1.
Fig. 4 is an enlarged view of a portion B in fig. 1.
Detailed Description
The following is further detailed by way of specific embodiments:
reference numerals in the drawings of the specification include: the device comprises a