A method for continuously preparing a high molecular water-absorbing resin at normal temperature and pressure in a closed system

Abstract

The application discloses a method for continuously preparing a high-molecular water-absorbing resin at normal temperature and pressure in a closed mode, and belongs to the technical field of high-molecular water-absorbing resin preparation. The application provides a method for continuously preparing a high-molecular water-absorbing resin at normal temperature and pressure in a closed mode, which comprises the following steps: 1, preparing a reaction solution; 2, continuously filling the reaction solution into a plastic film bag to form a first pre-prepared body which is continuously output; and 3, continuously performing a closed polymerization reaction on the reaction solution in the film bag through UV radiation. The application realizes the closed and continuous preparation of the high-molecular water-absorbing resin at normal temperature and pressure, does not need to use heating and pressurizing equipment, and does not discharge gas during the preparation process; on the one hand, the product preparation cost is reduced; on the other hand, the cleanness, safety and stability of the preparation process are ensured. In addition, the continuous preparation method can greatly improve the product preparation efficiency and preparation scale, the monomer conversion rate of the product is high, the residual monomer is low, and the water absorption performance is excellent.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high molecular water-absorbing resin preparation, in particular to a method for continuously preparing high molecular water-absorbing resin at normal temperature and pressure in a closed environment. BACKGROUND

[0002] High molecular water-absorbing resin (SAP) is a new type of functional polymer material, which can absorb water several hundred times of its own mass, and has good water retention capacity. SAP also has a three-dimensional network structure, and is insoluble in water and organic solvents. SAP has the properties of absorbing urine, blood, and absorbing fertilizers and organic drugs. Therefore, SAP has been widely used in agriculture, forestry, gardening, physiology, health, food, civil construction, daily chemical industry, and health care.

[0003] There are mainly two methods for preparing traditional SAP. One is belt polymerization, which is an open "explosive polymerization" polymerization production method using a continuous belt reactor. A large amount of volatile waste gas is generated due to the heat of polymerization, which can easily cause equipment corrosion and environmental pollution, and the monomer residue is high, and the output efficiency is low. The other is kettle polymerization, which is a method of generating high molecular water-absorbing resin by controlling the reaction conditions in a reaction kettle. The reaction liquid becomes solid in the later stage and needs to be pressed out under high pressure. If the reaction liquid ratio or the reaction condition control is improper, there is a risk of explosion. SUMMARY

[0004] In order to solve the problems of low safety and high cost in the preparation of related high molecular water-absorbing resin, the present application provides a method for continuously preparing high molecular water-absorbing resin at normal temperature and pressure in a closed environment. The reaction rate of the reaction liquid polymerization reaction is controlled based on the energy of UV light (Ultraviolet Rays, i.e. ultraviolet light), and no explosive polymerization occurs at normal temperature and pressure. No waste gas is generated in the closed environment, which ensures the safety of the preparation process. And it can realize the efficient continuous preparation of water-absorbing resin, greatly improve the preparation efficiency of water-absorbing resin, reduce the preparation cost, and the product has high monomer conversion rate, low residual monomer and excellent water absorption performance.

[0005] The present application provides a method for continuously preparing high molecular water-absorbing resin at normal temperature and pressure in a closed environment, which comprises a filling module, a packaging module, a first transmission module and a polymerization module connected in sequence.

[0006] The filling module comprises a material inlet and a continuous feeding assembly connected with the material inlet.

[0007] The continuous feeding assembly continuously outputs the reaction liquid through the material inlet, and the reaction liquid comprises a polymerization monomer solution.

[0008] The packaging module comprises an automatic bag making mechanism connected with the material inlet, and a continuous film feeding assembly connected with the automatic bag making mechanism.

[0009] The automatic bagging mechanism is used to continuously package the transparent plastic film provided by the continuous film supply assembly into continuous plastic reaction bags;

[0010] The preparation step comprises:

[0011] S1, using the packaging module to prepare the bottom and side edge sealing, and continuously produce the plastic reaction bag, at the same time, filling the reaction liquid into the plastic reaction bag through the feeding port of the filling module, and discharging the gas in the plastic reaction bag, to form the first preform continuously output;

[0012] S2, using the first transmission module to interface the first preform, and continuously transmitting to the polymerization module according to the output rate of the first preform;

[0013] S3, the polymerization module uses UV light to continuously irradiate the first preform, the UV light is used for UV radiation polymerization reaction of the reaction liquid, and continuously provides the energy of polymerization reaction, so that the reaction liquid occurs continuous controllable polymerization reaction in the sealed state of the plastic reaction bag wrapping, the reaction liquid is converted from liquid to solid, and the water absorbing resin gel is formed.

[0014] Using the above technical solution, the reaction liquid is placed in the sealed plastic reaction bag, and the continuous irradiation of the UV light makes the UV light directly participate in the polymerization reaction of the reaction liquid, and provides energy for the polymerization of the reaction liquid itself, thereby controlling the process of the polymerization reaction of the reaction liquid, avoiding the traditional way of initiating the reaction liquid by UV light, high temperature and initiator to initiate the explosive polymerization reaction of the reaction liquid, thereby causing a large amount of reaction gas and heat to be generated in the reaction process, which is difficult to ensure the safety and environmental protection requirements of the reaction process.

[0015] On this basis, the filling module and the packaging module can continuously generate the first preform, on the one hand, the long-time reaction requirement of the UV polymerization reaction can be completed in the conveying process, and the continuity and sufficiency of the reaction process can be ensured; on the other hand, the first preform can be continuously produced and reacted, thereby greatly improving the efficiency of the preparation method, and the efficiency of the entire preparation process can be regulated by the production rate of the first preform, having extremely flexible adaptability. And can improve the monomer conversion rate of the reaction liquid, reduce the residual monomer in the prepared water absorbing resin.

[0016] In some embodiments, the reaction liquid is a homopolymer or copolymer aqueous solution of hydrophilic polymer monomer, including acrylic acid monomer, acrylic acid salt monomer or acrylamide monomer, and the initial temperature of the reaction liquid is-10-25℃.

[0017] By adopting the technical scheme, the temperature of the reaction liquid is set to be-10-25℃, on the one hand, the temperature range conforms to the natural climate temperature of the factory processing environment, and is easy to realize and control; on the other hand, the temperature rising rate of the reaction liquid after starting the polymerization reaction can be controlled, so as to ensure the uniformity, controllability and continuity of the polymerization reaction of the reaction liquid.

[0018] In some embodiments, the polymerization module adopts UV light with a wavelength of 320-400 nm and an intensity of 1-30 mW / cm2.

[0019] By adopting the technical scheme, the intensity of the UV light is ensured to be greater than 1 mW / cm2, so that the radiant energy of the UV light can be efficiently utilized to continuously promote the controllable polymerization reaction of the reaction liquid; and the UV light can completely irradiate and penetrate the entire plastic reaction bag, so as to ensure that the reaction liquid in the plastic reaction bag can uniformly absorb the energy of the UV light, ensure the uniformity of the reaction process, improve the uniformity of the reaction liquid after the polymerization reaction, make the monomer conversion rate of the reaction liquid high, and the residual monomer low. At the same time, the intensity of the UV light is prevented from being too large, which increases the difficulty of control and affects the uniformity of the product.

[0020] In some embodiments, the first transmission module is a horizontal conveying belt;

[0021] The step S2 comprises:

[0022] The starting end of the first preform naturally slides to the surface of the conveying belt under the action of gravity;

[0023] The conveying belt drives the first preform towards the polymerization module, and makes the first preform lay flat on the surface of the conveying belt;

[0024] And the thickness of the first preform is 50-150 mm.

[0025] By adopting the technical scheme, the first preform can be stably laid on the surface of the conveying belt, which facilitates the subsequent irradiation of the first preform by the UV light; at the same time, the thickness of the first preform is 50-150 mm, which can ensure that the thickness of the first preform is not too large to ensure that the UV light can uniformly irradiate the first preform, and can also avoid that the thickness of the first preform is too small to affect the overall preparation efficiency.

[0026] In some embodiments, the polymerization module comprises a second transmission module which is connected to the first transmission module, and an irradiation device which is arranged opposite to the second transmission module;

[0027] The second transmission module receives the first preform of the first transmission module and uniformly transmits the first preform;

[0028] The light device forms stable UV light towards the surface of the second transmission module;

[0029] Step S3 comprises:

[0030] S31, using UV light to irradiate the first preform for a first duration, so that the flowability of the reaction solution in the first preform decreases to a first threshold value;

[0031] S32, the first preform is turned upside down, so that the bottom surface of the first preform faces the light device;

[0032] S33, every second duration, repeat the step S32 until the water-absorbing resin gel is formed.

[0033] The above technical solution is adopted to turn the first preform at regular intervals, ensure the uniformity of the controllable polymerization reaction of the reaction solution in the first preform, and guarantee the quality of the final product.

[0034] In some embodiments, the first duration is 5-100 min; the second duration is 5-60 min;

[0035] In the step S33, the number of times of repeating the step S32 is 1-8 times.

[0036] In some embodiments, the second transmission module comprises a plurality of transmission belts arranged horizontally and spaced apart in the thickness direction, and a turnover mechanism connecting adjacent two transmission belts;

[0037] The turnover mechanism comprises a first turnover belt and a second turnover belt arranged oppositely, and a turnover channel is formed between the first turnover belt and the second turnover belt;

[0038] At the entrance of the turnover channel, the first turnover belt is butt-jointed with the lower transmission belt, and the turnover channel is bent in the thickness direction, so that at the exit of the turnover channel, the second turnover belt is butt-jointed with the upper transmission belt; and the turnover channel can clasp and fix the first preform to avoid the first preform from sliding in the turnover channel;

[0039] A light device is arranged above each transmission belt;

[0040] The step S32 comprises:

[0041] When the first preform is transmitted to the end of the transmission belt, the first turnover belt and the second turnover belt clasp the first preform into the turnover channel;

[0042] The turnover channel turns the first preform upside down and transmits the turned first preform to the upper transmission belt.

[0043] By arranging multiple conveying belts in the thickness direction, the overall land area of the device can be reduced, and meanwhile, the turnover mechanism can be conveniently arranged between two adjacent conveying belts; and the turnover mechanism can stably convey the first preform to the upper conveying belt while turning over the first preform, thereby ensuring the continuity and stability of the entire preparation process.

[0044] In some embodiments, the continuous feeding assembly comprises a plurality of storage tanks for storing reaction liquid;

[0045] The plurality of storage tanks are connected to the feeding port and sequentially feed the feeding port;

[0046] The continuous output of reaction liquid comprises: when the volume of reaction liquid in the previous storage tank decreases to a set value, the next storage tank starts to feed the feeding port, so that the two storage tanks feed the feeding port at the same time until the reaction liquid in the previous storage tank is exhausted;

[0047] The exhausted storage tank is replenished with liquid to ensure continuous feeding of the feeding port.

[0048] In some embodiments, the continuous film feeding assembly provides a transparent plastic film, which is a transparent PE film, and continuously provides a strip-shaped transparent plastic film, the transparent plastic film comprising a first edge and a second edge along the conveying direction;

[0049] The automatic bag making mechanism comprises a plurality of edge sealing devices arranged along the forming direction of the plastic reaction bag;

[0050] After the first edge and the second edge of the transparent plastic film wrap around the conveying port, they overlap and enter the plurality of edge sealing devices, and any one of the plurality of edge sealing devices seals the first edge and the second edge.

[0051] By using the above technical solution, the first edge and the second edge can be sealed by any one of the plurality of edge sealing devices, so that when the edge sealing device for sealing is damaged or needs to be maintained, the remaining edge sealing devices can be used for sealing to ensure the continuity and reliability of the working process of the automatic bag making mechanism.

[0052] In some embodiments, the continuous film feeding assembly comprises a plurality of film feeding rolls, a splicing device and a buffer device;

[0053] Any one of the plurality of film feeding rolls connects the transparent plastic film to the splicing device and the buffer device in sequence;

[0054] The discharge port of the buffer device guides the transparent plastic film to the automatic bag making mechanism, the buffer device is used for buffering the transparent plastic film of the first length, and when the film supply roll stops supplying the film, the buffer device can continue to provide the transparent plastic film of the first length;

[0055] The continuous supply step of the transparent plastic film comprises:

[0056] The transparent plastic film of any one of the plurality of film supply rolls is sequentially transported to the splicing device and the buffer device, and the buffer device starts to store the transparent plastic film of the first length;

[0057] When the transparent plastic film of any one of the film supply rolls is used up, the splicing device clamps the tail end of the transparent plastic film, and the buffer device continues to transport the buffered transparent plastic film;

[0058] The head end of the transparent plastic film of any other one of the plurality of film supply rolls is connected to the splicing device;

[0059] The splicing device releases the clamping of the transparent plastic film after heat-sealing and connecting the tail end of the transparent plastic film and the head end of another transparent plastic film;

[0060] At this time, the buffer device starts to store the transparent plastic film while maintaining the transportation of the transparent plastic film until the transparent plastic film of the first length is stored, thereby realizing the continuous supply of the transparent plastic film.

[0061] By using the above technical scheme, when a film supply roll is used up, the buffer device can still continue to provide the transparent plastic film of the first length, so that another film supply roll is connected to the tail end of the transparent plastic film of the used film supply roll through the splicing device during the process of providing the transparent plastic film by the buffer device, thereby continuously supplying the transparent plastic film without stopping the preparation process. BRIEF DESCRIPTION OF DRAWINGS

[0062] Figure 1 It is a flowchart of a continuous closed preparation of a high molecular water-absorbing resin at room temperature and normal pressure according to an embodiment of the present application;

[0063] Figure 2 It is a structure diagram of a film roll unit, a splicing device, a buffer device and an automatic bag making mechanism according to an embodiment of the present application;

[0064] Figure 3 It is a side view structure diagram of an automatic bag making mechanism according to an embodiment of the present application.

[0065] Explanation of reference signs:

[0066] 1, film supply roll; 2, transparent plastic film; 3, first preform;

[0067] 10, filling module;

[0068] 20. Packaging module;

[0069] 30. Post-processing module;

[0070] 40. Aggregation module;

[0071] 100. Film roll unit; 110. Film roll fixing member; 120. Driving member; 130. Abutting member; 140. First roller set; 150. Second roller set; 160. Third roller set;

[0072] 200. Splicing device; 210. Heat sealing apparatus; 220. First guide roller; 230. Second guide roller;

[0073] 300. Buffering device; 310. Conveying roller; 320. Guide rail;

[0074] 400. Automatic bag making mechanism; 410. Filling tube; 420. Film bag forming mold; 430. Film clamping device; 431. Clamping plate; 440. Edge sealing device; 441. Driving wheel; 442. Driven wheel; 443. Conveyor belt; 450. Transverse sealing apparatus. DETAILED DESCRIPTION

[0075] The subject matter of the present application can be more easily understood and appreciated with reference to the following detailed description of the preferred embodiments and included examples. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of conflict between the definitions and the disclosure provided herein, the definition provided in this specification shall control. As used herein, the term "made" is synonymous with "comprising." As used herein, the terms "comprise", "comprises" and "comprising" are used in the sense of "including", "includes" or "include", and not by way of

[0076] The conjunctive term "consisting of" precludes any element, step, or ingredient not specifically recited. If used in the claims, this phrase shall not be construed to mean that the claimed subject matter is composed of the specific elements recited. The phrase "consisting of" shall not be interpreted to mean that any element, step or ingredient not specifically recited is excluded from the claimed subject matter. When the phrase "consisting of" follows the introductory clauses "a", "an" or "the", it defines the scope of a claim with the exclusion of equivalents.

[0077] When equivalent, concentration, or other value or parameter is expressed in a range or a preferred range or a series of upper preferred values and lower preferred values, it is to be understood that the stated range or preferred range includes all ranges formed from any of the upper preferred values and any of the lower preferred values, even if the range is not expressly stated. For example, if a range is stated as "1 to 5," the described range should be interpreted to include ranges of "1 to 4," "1 to 3," "1 to 2," "1 to 2 and 4 to 5," "1 to 3 and 5," etc. When numerical ranges are described herein, unless otherwise stated, the range is intended to include both the upper and lower values and all intervening values of the range.

[0078] The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. "Optional" or "any of" means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event occurs and instances where it does not.

[0079] Approximating language should also be construed to mean and provide support for modifying or changing by approximations or equivalents. By way of example, a numerical value should be construed in accordance with the principles that underlie the approximating language, so that the numerical value is not too narrowly interpreted. In this application, ranges are used as a shorthand for describing a group of values. Each grouping of a range is individually disclosed and individually considered. For example, a range of "1 to 5" is individually disclosed as a range of "1 to 4," "1 to 3," "1 to 2," "1 to 2 and 4 to 5," "1 to 3 and 5," etc. In certain instances, the approximating language can correspond to the precision of an instrument for measuring the value. Numerical ranges include all values from and including the lower and the upper values, in increments of one unit. In this application, the use of "about" or "approximately" in connection with a value capably means that the value is the recited value, plus or minus a margin within ten percent (10%) of the recited value, unless otherwise stated.

[0080] In addition, the indefinite articles "a" and "an" preceding an element or component of the application are intended to be construed to mean either one or more than one of that element or component. As a result, the terms "a" and "an" should be interpreted to mean "at least one" or "one or more." As used herein, the indefinite articles "a" and "an" are used interchangeably in the disclosure.

[0081] It should be noted that the conventional explosive polymerization reaction is initiated by UV light (Ultraviolet Rays), high temperature and initiator as the reaction liquid, which is a rapid polymerization reaction by the UV light, high temperature and initiator of part of the reaction liquid, and the high temperature generated by the rapid polymerization reaction of the part of the reaction liquid and other initiators in the reaction liquid, thereby continuously initiating the polymerization reaction and producing a chain reaction to form the explosive polymerization phenomenon, resulting in high temperature, high pressure and gas by-products. (Wherein, the role of UV light is the same as that of high temperature, mainly to improve the stability of the reaction liquid to initiate the explosive polymerization reaction, and does not participate in the subsequent polymerization reaction of the reaction liquid after the initiation of the explosive polymerization reaction).

[0082] Therefore, in the prior art, in order to reduce the influence of high temperature and high pressure generated by explosive polymerization reaction, the safety and controllability of the preparation process can also be ensured by reducing the volume of the reaction solution participating in the polymerization reaction, for example, belt polymerization, which requires that the prepared raw materials are coated on the conveyor belt in a small amount and uniformly, and are placed in an open environment to provide rapid expansion of the volume and emission of the temperature during the explosive polymerization reaction of the reaction solution; then, the raw materials on the conveyor belt are heated to initiate the polymerization reaction; however, this method can only uniformly coat a small amount of reaction solution on the conveyor belt, and the thickness is extremely small and difficult to seal (the thickness is usually less than 30 mm), on the one hand, the efficiency of the polymerization reaction is low and waste gas is easily generated, which pollutes the indoor environment of the factory or increases the cost of waste gas treatment. On the other hand, the thickness of the reaction solution is extremely small, and it is difficult to control the uniformity of the polymerization reaction, resulting in more residual monomers in the final product and poor quality.

[0083] In the kettle reaction, the reaction solution is placed in a reaction kettle with high sealing performance and strength to ensure the sealing performance of the reaction solution during the polymerization reaction. However, the product after the polymerization reaction of the reaction solution is a gel-like solid structure, and high pressure is required to press the product out of the reaction kettle after the polymerization reaction, and once the reaction condition control deviates during the polymerization reaction, the explosive polymerization reaction of the reaction solution is easily triggered, thereby generating high temperature and high pressure, which easily causes the safety risk of explosion of the reaction kettle. Therefore, this method has extremely high requirements for the reaction kettle and the production environment, and the polymerization product produced by the explosive polymerization reaction is difficult to control the degree of monomer conversion of the polymerization product due to the fast polymerization reaction process, resulting in high residual monomers in the product and poor quality. Further, the reaction process needs to be closed, and continuous production of the product cannot be achieved, and the preparation efficiency of the product cannot be improved.

[0084] Therefore, please refer to Figure 1 , Figure 2 and Figure 3 , Figure 1 is a flow diagram of a continuous closed preparation of a high molecular water-absorbing resin at normal temperature and pressure according to an embodiment of the present application, Figure 2 is a structure diagram of a film roll unit, a splicing device, a buffer device and an automatic bag making mechanism provided by the embodiment of the present application, Figure 3 is a side view structure diagram of the automatic bag making mechanism provided by the embodiment of the present application.

[0085] It should be noted that the structure diagrams not shown in the present application can be realized by using conventional technical means in the prior art.

[0086] As shown in Figure 1 and Figure 2 , the embodiment of the present application provides a method for continuously and closedly preparing a high molecular water-absorbing resin at normal temperature and pressure, which comprises a filling module 10, a packaging module 20, a first transmission module (not shown in the figure) and a polymerization module 40 connected in sequence.

[0087] The filling module 10 comprises a feeding port and a continuous feeding assembly (not shown in the figure) connected with the feeding port;

[0088] The continuous feeding assembly continuously outputs the reaction liquid through the feeding port, and the reaction liquid comprises a polymerization monomer solution;

[0089] The packaging module 20 comprises an automatic bag making mechanism 400 which is connected with the feeding port, and a continuous film feeding assembly (not shown in the figure) connected with the automatic bag making mechanism 400;

[0090] The automatic bag making mechanism 400 is used to continuously package the transparent plastic film 2 provided by the continuous film feeding assembly into a continuous plastic reaction bag;

[0091] The preparation steps comprise:

[0092] S1, using the packaging module 20 to prepare a plastic reaction bag which is continuously produced and sealed at the bottom, and at the same time, filling the reaction liquid into the plastic reaction bag through the feeding port of the filling module 10, and discharging the gas in the plastic reaction bag to form a first preform 3 which is continuously outputted;

[0093] S2, using the first transmission module to interface the first preform 3, and continuously transmitting the first preform 3 to the polymerization module 40 according to the output rate of the first preform 3;

[0094] S3, the polymerization module 40 continuously irradiates the first preform 3 with UV light, and the UV light is used for UV radiation polymerization reaction of the reaction liquid, and continuously provides energy for the polymerization reaction, so that the reaction liquid occurs a continuous controllable polymerization reaction in a closed state wrapped by the plastic reaction bag, and the reaction liquid is converted from liquid state to solid state to form a water absorbing resin gel.

[0095] In the process, the reaction liquid is continuously irradiated by the UV light, and the UV light directly participates in the polymerization reaction of the reaction liquid, the reaction liquid uses the energy of the UV light to stagely break the chemical bonds of monomers, and the chemical bonds of monomers in the reaction liquid perform a controllable polymerization reaction under the action of the UV light, so as to avoid the chain reaction similar to the explosive polymerization reaction, and realize the controllable polymerization reaction. Therefore, no or only a small amount of additional gas by-products are generated, so that the reaction liquid can be placed in a closed environment such as a plastic reaction bag to perform a controllable polymerization reaction.

[0096] Further, due to the controllability of the polymerization reaction process of the reaction liquid, the polymerization reaction of the reaction liquid which is sufficiently irradiated by the UV light is extremely sufficient, so that the purity of the reaction product is extremely high, thereby the purity and quality of the final product can be greatly improved.

[0097] Therefore, based on the above polymerization mode, the embodiment of the present application can continuously generate the first preform 3 through the filling module 10 and the packaging module 20, so as to realize the continuity of the reaction process. On the one hand, the efficiency of the preparation method is greatly improved; on the other hand, the efficiency of the entire preparation process can be regulated through the production rate of the first preform 3, which has extremely flexible adaptability.

[0098] The polymer water-absorbing resin can be continuously produced in a closed environment at normal temperature and pressure, and the reaction conditions are mild, efficient and controllable. The reaction process does not produce waste gas and is environmentally friendly. The reaction liquid can efficiently utilize the radiation energy of UV light to continuously promote the controllable polymerization reaction of the reaction liquid, improve the fullness of the reaction liquid polymerization reaction, and increase the monomer conversion rate of the reaction liquid and reduce the residual monomer. At the same time of improving the performance requirements of the water-absorbing resin product, the low cost and high efficiency of industrialization and popularization and application are met.

[0099] In one embodiment, a post-processing module 30 for processing the prepared water-absorbing resin gel is further included. The post-processing module 30 can perform processes such as shearing, drying, and surface treatment on the water-absorbing resin gel, and prepare the final polymer water-absorbing resin product.

[0100] In one embodiment, the reaction liquid is an aqueous solution of homopolymer or copolymer monomers of hydrophilic polymers, including acrylic acid monomers, acrylic acid salt monomers, or acrylamide monomers. The initial temperature of the reaction liquid is -10-25°C (natural climate temperature), and the neutralization degree is 50-90%.

[0101] On the one hand, the use of initiators can avoid the explosive polymerization reaction of the reaction liquid caused by the initiators, which can cause high temperature or a large amount of gas and safety hazards. At the same time, the use of raw materials is reduced, and the cost of the preparation process is reduced. On the other hand, by setting the temperature of the reaction liquid to -15-30°C, the temperature of the reaction liquid after the polymerization reaction starts will not rise too fast, thereby affecting the uniformity and controllability of the polymerization reaction of the reaction liquid.

[0102] In one embodiment, the initial temperature of the solution of acrylic acid monomers or sodium acrylate monomers is -10-25°C, and can also be -5-15°C. In other alternative embodiments, the initial temperature can be less than -10°C or more than 25°C.

[0103] In one embodiment, the reaction liquid can be prepared by acid-base neutralization, and the neutralization degree can be 50-90%. In other alternative embodiments, the neutralization degree of the reaction liquid can be less than 50% or more than 90%.

[0104] In another embodiment, when the reaction solution is an acrylic monomer solution or an acrylamide monomer solution, the concept of neutralization degree can also be absent.

[0105] In one embodiment, the polymerization module 40 uses UV light with a wavelength of 320-400 nm and an intensity of 1-30 mW / cm2. When the intensity of the UV light is greater than 1 mW / cm2, the radiant energy of the UV light can be efficiently utilized to continuously drive the controllable polymerization reaction of the reaction solution; and the UV light can be fully irradiated and penetrated through the entire plastic reaction bag, ensuring that the reaction solution in the plastic reaction bag can uniformly absorb the energy of the UV light, ensuring the uniformity of the reaction process and improving the uniformity of the reaction solution after polymerization. At the same time, it avoids that the UV light intensity is too large, which leads to a too fast polymerization reaction, increases the control difficulty, and affects the uniformity of the product.

[0106] In one embodiment, the light source of the UV light is set to an ultraviolet LED lamp, and the intensity of the UV light is more preferably 3-15 mW / cm2.

[0107] When the reaction solution is placed in the first preform 3 (the thickness can exceed 50 mm) formed by a sealed transparent plastic bag to perform a controllable polymerization reaction, by using an ultraviolet LED lamp with an illumination intensity limited to 3-30 mW / cm2 as a light source, it can be ensured that the actual other heat generated by the UV light is extremely low, and most of its energy is directly used to provide energy for the polymerization process, thereby ensuring a mild polymerization reaction process and a controllable reaction process.

[0108] At the same time, since the heat during the polymerization reaction of the first preform 3 is controllable, dangerous reactions such as thermal polymerization or violent polymerization are less likely to occur, thereby greatly increasing the thickness of the first preform 3 under UV light illumination in actual production. On the one hand, it can ensure that the ultraviolet light energy can fully penetrate the entire reaction solution, so that the reaction solution can fully perform a polymerization reaction; on the other hand, the increase in the thickness of the first preform 3 can greatly increase the volume of the water-absorbing resin product under the same irradiation area, thereby greatly improving the yield and output efficiency of the water-absorbing resin.

[0109] It should be noted that the first preform 3 can be formed by sealing the reaction solution with a flexible plastic reaction bag, and the flowability of the reaction solution is relatively large when the reaction solution has not been fully polymerized.

[0110] Therefore, in order to ensure the stability of the transmission process, in one embodiment, the first transmission module is set to a horizontal conveying belt; thereby ensuring stable transmission of the first preform 3.

[0111] Step S2 includes:

[0112] The starting end of the first preform 3 naturally slides down to the surface of the conveying belt under the action of gravity;

[0113] In one aspect, under the action of gravity, the excess gas in the plastic reaction bag can be discharged from the upper opening, thereby reducing the gas falling into the inside of the first preform 3 of the conveying belt to ensure the uniformity and quality of the polymerization process.

[0114] At the same time, the conveying belt drives the first preform 3 towards the polymerization module 40 and makes the first preform 3 lay flat on the surface of the conveying belt; and the thickness of the first preform 3 is 50-150 mm.

[0115] It should be noted that the polymerization reaction of the reaction solution in the first preform 3 relies on the direct irradiation of ultraviolet light, and the ultraviolet light has high penetration, so the thickness of the first preform 3 can exceed 50 mm, thereby greatly improving the efficiency of the entire preparation process. The preparation thickness of the traditional belt type "explosion polymerization" reaction is usually not more than 30 mm.

[0116] Further, since the intensity of the UV light decays when penetrating the first preform 3, and the first preform 3 has high fluidity before the reaction, and the first preform 3 needs to be turned over in the subsequent preparation process, therefore, in the preferred embodiment, the thickness of the first preform 3 can be not more than 150 mm, thereby reducing the requirement for the wrapping strength of the plastic reaction bag, and facilitating the UV polymerization, transportation and turning over of the first preform 3.

[0117] At the same time, it should also be noted that the energy of the UV light decreases with the increase of the penetration distance in the process of penetrating the first preform 3, thereby causing the polymerization reaction efficiency of the first preform 3 to be higher on the side close to the UV light source and lower on the side away from the UV light source, thereby making it difficult to ensure the uniformity of the overall polymerization process of the first preform 3. Therefore, the thickness of the first preform 3 is not suitable to exceed 150 mm.

[0118] In other alternative embodiments, in the case of small-batch production or without considering the preparation efficiency, the thickness of the first preform 3 can also be less than 50 mm, for example, set to 30 mm, 40 mm, 45 mm, etc. At the same time, in the case of using high-intensity UV light irradiation, or simultaneously irradiating both sides of the first preform 3, etc., the thickness of the first preform 3 can also exceed 150 mm, for example, set to 160 mm, 180 mm, 200 mm, etc.

[0119] In one embodiment, the starting end of the transparent plastic film 2 can be heat sealed and closed, then the reaction solution is poured in, and the gas in the starting end of the transparent plastic film 2 is evacuated under the action of gravity, thereby forming the starting end of the first preform 3.

[0120] It should be noted that the greater the width of the first preform 3, the greater the volume of the reaction liquid it contains, the more difficult it is to turn over, and the greater the strength of the plastic reaction bag it contains and the area required for UV light irradiation. Therefore, in an embodiment, the width of the first preform 3 can be 800-1500mm.

[0121] In an embodiment, the polymerization module 40 includes a second conveying module that interfaces with the first conveying module, and a light irradiation device that is arranged opposite the second conveying module;

[0122] The second conveying module receives the first preform 3 of the first conveying module and uniformly conveys the first preform 3;

[0123] The light irradiation device forms stable UV light irradiation towards the surface of the second conveying module.

[0124] It should be noted that due to the energy attenuation of UV light during penetration of the first preform 3, when the first preform 3 is only subjected to unilateral UV light irradiation, the polymerization reaction rates on the upper and lower sides of the first preform 3 are different, affecting the uniformity of the polymerization process of the first preform 3.

[0125] Therefore, in an embodiment, step S3 includes:

[0126] S31, using UV light to irradiate the first preform 3 for a first duration, so that the fluidity of the reaction liquid in the first preform 3 decreases to a first threshold value;

[0127] S32, turning over the first preform 3 upside down so that the bottom surface of the first preform 3 faces the light irradiation device;

[0128] S33, repeating step S32 every second duration until the water-absorbing resin gel is formed. So that the upper and lower sides of the first preform 3 can be subjected to uniform UV light irradiation, thereby ensuring the uniformity of the overall polymerization process of the first preform 3, thereby improving the purity and quality of the water-absorbing resin.

[0129] In an embodiment, the first duration is 5-100min; the second duration is 5-60min;

[0130] In step S33, the number of times step S32 is repeated is 1-8 times.

[0131] It should be noted that the first duration and the second duration can be freely set according to the thickness of the first preform 3 and the intensity of the UV light, as long as the fluidity can decrease to the first threshold value after the first preform 3 is irradiated for the first duration, so as to facilitate the turning over of the first preform 3. The second duration can be determined and controlled according to the conveying rate and length of the second conveying module, and depends on the total duration of the full reaction of the first preform 3 and the required number of turns.

[0132] Therefore, in other alternative embodiments, the first time length can also be less than 5 minutes or greater than 100 minutes; the second time length can be less than 5 minutes or greater than 60 minutes; and the number of times of turning over can be greater than 8.

[0133] It should be noted that the first preform 3 has relatively large fluidity at the beginning of the reaction, so it needs to be transported by a horizontal conveying belt, and in order to realize the continuity of the preparation process, the first preform 3 needs to be transported in a specific path in one direction. At the same time, at least one turning over of the first preform 3 needs to be realized on the path to complete the double-sided irradiation of the first preform 3.

[0134] Therefore, in one embodiment, the second conveying module includes a plurality of conveying belts arranged in the thickness direction and horizontally, and a turning over mechanism (not shown in the figure) connecting adjacent two conveying belts;

[0135] The turning over mechanism includes oppositely arranged first and second turning over belts, and a turning over channel is formed between the first and second turning over belts;

[0136] At the entrance of the turning over channel, the first turning over belt is butt-jointed with the lower conveying belt, and the turning over channel is bent in the thickness direction, so that at the exit of the turning over channel, the second turning over belt is butt-jointed with the upper conveying belt; and the turning over channel can clasp and fix the first preform 3 to avoid the first preform 3 from sliding in the turning over channel;

[0137] The upper side of each conveying belt is correspondingly provided with an irradiation device;

[0138] Step S32 includes:

[0139] When the first preform 3 is conveyed to the end of the conveying belt, the first and second turning over belts clasp the first preform 3 into the turning over channel;

[0140] The turning over channel drives the first preform 3 to turn over up and down, and conveys the turned over first preform 3 to the upper conveying belt.

[0141] Among them, arranging the plurality of conveying belts in the thickness direction is beneficial to reduce the overall floor area of the equipment, and at the same time, it is convenient to arrange the turning over mechanism between adjacent two conveying belts; and the turning over mechanism can stably convey the first preform 3 to the upper conveying belt while turning over the first preform 3, ensuring the continuity and stability of the entire preparation process.

[0142] In other alternative embodiments, the plurality of conveying belts can also be arranged in an S shape, a meander shape, etc. on the same horizontal plane, so as to facilitate the stable conveying of the first preform 3, and also avoid the additional energy loss caused by conveying the first preform 3 in the thickness direction.

[0143] It should be noted that the first preform 3 is a flexible structure of a plastic reaction bag wrapping liquid, and the reaction product after the reaction liquid of the first preform 3 polymerizes is in a gel state and has high flexibility. Therefore, in other alternative embodiments, the first preform 3 between adjacent conveying belts can be manually turned over, and at the same time, the reaction state of the first preform 3 can be manually detected during the turning over process.

[0144] In one embodiment, the continuous feeding assembly includes a plurality of storage tanks for storing reaction liquid;

[0145] The plurality of storage tanks are connected to the feeding port and sequentially feed the feeding port;

[0146] The process of continuously outputting the reaction liquid includes: when the volume of the reaction liquid in the previous storage tank decreases to a set value, the next storage tank starts to feed the feeding port, so that the two storage tanks feed the feeding port at the same time until the reaction liquid in the previous storage tank is exhausted;

[0147] The exhausted storage tank is replenished with liquid to ensure continuous feeding of the feeding port.

[0148] In one embodiment, the transparent plastic film 2 provided by the continuous film feeding assembly is set as a transparent PE film, and a strip-shaped transparent plastic film 2 is continuously provided, and the transparent plastic film 2 includes a first edge and a second edge in the conveying direction;

[0149] The automatic bag making mechanism 400 includes a plurality of edge sealing devices 440 arranged in the direction of forming the plastic reaction bag;

[0150] The first edge and the second edge of the transparent plastic film 2 overlap after wrapping the conveying port and enter the plurality of edge sealing devices 440, and any one of the plurality of edge sealing devices 440 heat seals the first edge and the second edge.

[0151] Among them, the plurality of edge sealing devices 440 can heat seal the first edge and the second edge, so that when the edge sealing device 440 that is heat sealed is damaged or needs to be maintained, the remaining edge sealing devices 440 can be used for heat sealing, to ensure the continuity and reliability of the working process of the automatic bag making mechanism 400.

[0152] In one embodiment, the continuous film feeding assembly includes a plurality of film feeding rolls 1, a splicing device 200, and a buffer device 300;

[0153] Any one of the plurality of film feeding rolls 1 sequentially connects the transparent plastic film 2 to the splicing device 200 and the buffer device 300;

[0154] The discharge port of the buffer device 300 guides the transparent plastic film 2 to the automatic bag making mechanism 400, the buffer device 300 is used to buffer the first length of the transparent plastic film 2, and when the film roll 1 stops supplying the film, the buffer device 300 can continue to provide the first length of the transparent plastic film 2;

[0155] The continuous supply step of the transparent plastic film 2 includes:

[0156] The transparent plastic film 2 of any one of the plurality of film rolls 1 is sequentially transported to the splicing device 200 and the buffer device 300, and the buffer device 300 starts to store the first length of the transparent plastic film 2;

[0157] When the transparent plastic film 2 of any one of the film rolls 1 is used up, the splicing device 200 clamps the tail end of the transparent plastic film 2, and the buffer device 300 continues to buffer the transparent plastic film 2;

[0158] The transparent plastic film 2 of any other one of the plurality of film rolls 1 is connected to the splicing device 200 at the head end;

[0159] The splicing device 200 releases the clamping of the transparent plastic film 2 after heat-sealing the tail end of the transparent plastic film 2 and the head end of the other transparent plastic film 2;

[0160] At this time, the buffer device 300 starts to store the transparent plastic film 2 while continuing to transport the transparent plastic film 2 until the first length of the transparent plastic film 2 is stored, thereby realizing the continuous supply of the transparent plastic film 2.

[0161] When a film roll 1 is used up, the buffer device 300 can still continue to provide the first length of the transparent plastic film 2, so that in the process of providing the transparent plastic film 2 by the buffer device 300, another film roll 1 is connected to the tail end of the transparent plastic film 2 of the used film roll 1 through the splicing device 200, thereby continuously supplying the transparent plastic film 2 without stopping the preparation process.

[0162] As shown in FIGS. Figure 2 and Figure 3 In one embodiment, the film roll 1 is arranged on the film roll unit 100, and the film roll unit 100 provides the transparent plastic film 2 to the automatic bag making mechanism 400 through the buffer device 300.

[0163] The splicing device 200 is arranged between the film roll unit 100 and the inlet of the buffer device 300, the transparent plastic film 2 of the film roll unit 100 is connected to the inlet of the buffer device 300 through the splicing device 200, and the splicing device 200 can clamp the transparent plastic film 2.

[0164] The automatic bag making mechanism 400 is arranged corresponding to the discharge port of the buffer device 300, and continuously pulls the transparent plastic film 2 of the discharge port, and continuously makes the plastic reaction bag, and continuously fills the plastic reaction bag to form the continuous first preform.

[0165] In one embodiment, the buffer device 300 comprises a plurality of movable conveying rollers 310 distributed on both sides of the first straight line, and the rotating shafts of the conveying rollers 310 are parallel to each other and perpendicular to the first straight line. The feeding port and the discharge port of the buffer device 300 are located on the first straight line.

[0166] The transparent plastic film 2 is wound in a zigzag shape through the plurality of conveying rollers 310 on both sides of the first straight line.

[0167] The buffer device 300 has a first state and a second state, and

[0168] In the first state, the connecting device 200 is not clamped, and the plurality of conveying rollers 310 apply a tensioning force to the transparent plastic film 2, so that the transparent plastic film 2 is continuously transmitted to the discharge port of the buffer device 300 at a preset tensioning force, and a certain length of the transparent plastic film 2 is stored through the distance between the plurality of conveying rollers 310;

[0169] In the second state, the connecting device 200 is clamped, and at least one conveying roller 310 moves towards the first straight line, and the transparent plastic film 2 is continuously transmitted to the discharge port of the buffer device 300 while maintaining the preset tensioning force, that is, when the connecting device 200 is clamped, the feeding port of the buffer device 300 no longer feeds, at this time, the storage of the transparent plastic film 2 is released by moving the conveying roller 310, so that the discharge port of the buffer device 300 can still continuously discharge, avoiding the stop of the subsequent process steps, such as filling, and the polymerization reaction, unpacking, and cutting after filling, etc. steps, to realize the continuous and reliable process, thereby ensuring the production efficiency and controlling the production cost. Preferably, the length of the stored transparent plastic film 2, i.e. the storage length, is 10-20 m.

[0170] In one embodiment, the two ends of the conveying roller 310 are slidingly arranged on the guide rail 320, and are connected with independent driving members to drive the conveying roller 310 to slide on the guide rail 320.

[0171] This way improves the movement reliability of the conveying roller 310 through the guide rail 320, thereby improving the storage release reliability, ensuring that the transparent plastic film 2 is continuously transmitted at a preset tensioning force, maintaining the normal operation of the subsequent process, and realizing the closed and continuous preparation of the hydrophilic resin. Moreover, by connecting each conveying roller 310 with an independent driving member, the independent control movement of each conveying roller 310 is realized, further improving the movement reliability of the conveying roller 310.

[0172] In one embodiment, the extension direction of each guide rail 320 is perpendicular to the first straight line, ensuring that the conveying roller 310 moves along a direction perpendicular to the first straight line, reducing the control difficulty of the conveying roller 310 movement distance and the storage release ratio, and further improving the storage release reliability.

[0173] In one embodiment, the system further comprises a control unit connected to each driving member.

[0174] When the first state is switched to the second state, the control unit controls at least one conveying roller 310 close to the feeding port of the buffer device 300 to move towards the first straight line by a first distance, for example, 1 / 4-3 / 4 of the length of the guide rail 320, and the tension of the transparent plastic film 2 at the feeding port of the buffer device 300 is quickly reduced through the movement of the conveying roller 310, avoiding the sudden increase of the transparent plastic film 2 tension at this position caused by the sudden stop of feeding, and affecting the transparent plastic film 2 tension in the buffer device 300, thereby affecting the overall process.

[0175] In the second state, the control unit controls at least one conveying roller 310 to move towards the first straight line, so that the transparent plastic film 2 at the discharge port of the buffer device 300 is continuously fed, that is, the movement of the conveying roller 310 is gradually controlled in coordination with the reduction of the storage, ensuring that the tension remains unchanged.

[0176] When the second state is switched to the first state, the control unit controls at least one conveying roller 310 close to the feeding port of the buffer device 300 to move away from the first straight line by a second distance, for example, 1 / 4-3 / 4 of the length of the guide rail 320, and the tension of the transparent plastic film 2 at the feeding port of the buffer device 300 is quickly increased through the movement of the conveying roller 310, avoiding the loosening and accumulation of the transparent plastic film 2 at this position caused by the sudden decrease of the transparent plastic film 2 tension at the initial stage of feeding, and affecting the transparent plastic film 2 tension in the buffer device 300, thereby affecting the overall process; then, the control unit controls at least one conveying roller 310 to move away from the first straight line until all conveying rollers 310 move to the end of the corresponding guide rail 320 away from the first straight line, realizing storage and restoring normal operation.

[0177] In one embodiment, in the second state, the control unit controls a plurality of conveying rollers 310 to move towards the first straight line in order from near to far from the discharge port of the buffer device 300, and when the previous conveying roller 310 moves to the first straight line, the next conveying roller 310 moves, which can quickly respond to the subsequent process operation beat, adjust the discharge film strip tension, so that the transparent plastic film 2 at the discharge port of the buffer device 300 is continuously fed, thereby improving the output stability and reliability of the transparent plastic film 2 at the feeding port of the buffer device 300, and ensuring the normal operation of the subsequent filling process.

[0178] In an embodiment, the splicing device 200 comprises a heat sealing device 210, a first guide assembly arranged between the discharge port of the film roll unit 100 and the heat sealing device 210, and a second guide assembly arranged between the heat sealing device 210 and the inlet port of the buffer device 300.

[0179] In an embodiment, the first guide assembly comprises two first guide rollers 220 arranged oppositely, which are used to guide the transparent plastic film 2 output by the film roll unit 100 to the heat sealing device 210 in a first state, and guide the plurality of transparent plastic films 2 output by the film roll unit 100 to overlap and be transmitted to the heat sealing device 210 in a second state, so as to improve the butt joint accuracy of the plurality of transparent plastic films 2, thereby improving the film splicing effect.

[0180] In an embodiment, the two first guide rollers 220 are slidingly arranged in the first guide rail 320 and can be fixed in the first guide rail 320 by fasteners, and the first guide rail 320 is vertically arranged, so that the height position of the two first guide rollers 220 can be adjusted according to the position of the splicing device 200, thereby improving the butt joint accuracy of the plurality of transparent plastic films 2 and improving the film splicing effect.

[0181] In a specific embodiment, the heat sealing device 210 is used to clamp and heat seal the plurality of transparent plastic films 2 located in the heat sealing device 210 in the second state. For example, the film splicing device in the prior art such as CN201863420U can realize clamping and heat sealing film splicing.

[0182] It can be understood that the heat sealing device 210 can also comprise a cutting mechanism, so as to cut off the film strip about to be used up, so as to reduce the overlapping part of the plurality of film strips after film splicing, and improve the quality of the film strip.

[0183] In an embodiment, the second guide assembly comprises a second guide roller 230, and the second guide roller 230 is used to guide the transparent plastic film 2 at the discharge port of the heat sealing device 210 to the inlet port of the buffer device 300.

[0184] In an embodiment, the second guide roller 230 is slidingly arranged in the second guide rail 320 and can be fixed in the second guide rail 320 by fasteners, and the second guide rail 320 is vertically arranged, so that the height position of the second guide roller 230 can be adjusted according to the position of the splicing device 200 and the inlet port of the buffer device 300, thereby improving the butt joint accuracy of the plurality of transparent plastic films 2 and improving the film splicing effect.

[0185] In an embodiment, the film roll unit 100 comprises a plurality of film roll fixing members 110, a driving member 120 corresponding to each of the plurality of film roll fixing members 110, and an abutting member 130 corresponding to each of the driving members 120.

[0186] The film roll holder 110 is used to connect the film supply roll 1, which is a roll of transparent plastic film 2. Multiple film roll holders 110 can store multiple film supply rolls 1 simultaneously, thereby shortening the film splicing time and improving production efficiency when a film supply roll 1 is about to run out. It also reduces the length of the transparent plastic film 2 stored in the buffer device 300, thereby controlling the volume of the buffer device 300 and improving control reliability. Typically, two film roll holders 110 are sufficient.

[0187] The drive unit 120 is kept in contact with the edge of the film supply roll 1, that is, the outermost surface film of the film supply roll 1, through the abutment member 130, and drives the film supply roll 1 to rotate to unfold the transparent plastic film 2. That is, the drive unit 120 directly drives the film supply roll 1 to rotate and unwind. Compared with the conventional method of driving the film supply roll 1 to rotate through the film roll fixing member, it can directly adapt to different types of film supply rolls 1, with high versatility and effective cost control.

[0188] It should be noted that conventional film roll unwinding machines use film roll fixing components, such as unwinding shafts, to drive the film roll 1 to rotate and unwind. The unwinding shaft needs to be customized according to the type of film roll, which is costly, has poor versatility, and is inconvenient to operate.

[0189] In one embodiment, the film roll unit 100 further includes a first roller group 140, a second roller group 150 and a third roller group 160 arranged sequentially along the conveying direction of the transparent plastic film 2.

[0190] In one embodiment, the first guide assembly, the heat sealing device 210, and the second guide assembly are located on the same straight line.

[0191] In one embodiment, the abutment 130 is a pneumatic rod.

[0192] In one embodiment, the drive element 120 is an electric roller.

[0193] Please see Figure 3 and combined Figure 2 Understand. Figure 3 This is a side view of the automatic bag-making mechanism 400 provided in an embodiment of this application.

[0194] In one embodiment, the automatic bag-making mechanism 400 includes a filling tube 410 that docks with a feed inlet and a film bag forming assembly.

[0195] The film bag forming assembly is used to continuously receive transparent plastic film 2 and to form a reaction bag by connecting the first and second sides of the transparent plastic film 2 along its length, that is, to form a closed (except for the front opening for continuous filling) and continuous reaction bag.

[0196] The filling tube 410 extends into the film bag forming assembly and continuously fills the plastic reaction bag, i.e. to realize the preparation of a closed and continuous first preform, and to further provide a basis for realizing the closed and continuous preparation of the hydrophilic resin.

[0197] In one embodiment, the film bag forming assembly comprises, in sequence along the filling direction, a film bag forming die 420, a film clamping device 430, a plurality of edge sealing devices 440, and a transverse sealing device 450.

[0198] In one embodiment, the film bag forming die 420 is trumpet-shaped and covers the circumference of the filling tube 410, and is used to guide the first edge and the second edge of the transparent plastic film 2 in the length direction to cover the circumference of the filling tube 410.

[0199] In one embodiment, the film clamping device 430 is used to guide the first edge and the second edge of the transparent plastic film 2 in the length direction to adhere, and then the edge sealing device 440 is used for edge sealing, which improves the flatness of the edge sealing, thereby improving the firmness of the edge sealing, and further improving the quality of the continuous reaction bag, thereby providing a basis for realizing continuous filling.

[0200] In one embodiment, the film clamping device 430 comprises two clamping plates 431 arranged oppositely, and the clamping plates 431 have a first length along the filling direction and extend to the feeding port of the closest edge sealing device 440, so that the film clamping device 430 has a simple structure and closely cooperates with the edge sealing device 440, further ensuring that the transparent plastic film 2 entering the edge sealing device 440 is flatly adhered on both sides, thereby improving the flatness and firmness of the edge sealing.

[0201] In one embodiment, the edge sealing device 440 is used to continuously pull and fixedly connect the side edges of the transparent plastic film 2 after adhesion.

[0202] The plurality of edge sealing devices 440 can be operated alternately or synchronously. Preferably, the plurality of edge sealing devices 440 synchronously pull the transparent plastic film 2, and only one edge sealing device 440 fixedly connects the side edges of the transparent plastic film 2 after adhesion, for example, by heat sealing connection, i.e. alternating sealing, synchronous pulling, so as to achieve better sealing effect and pulling effect, and at the same time, when one edge sealing device 440 fails, the alternation ensures continuous production.

[0203] In one embodiment, the transverse sealing device 450 is used to fixedly connect the bottom of the transparent plastic film 2 after the two sides are fixed, so as to form a plastic reaction bag. It can be understood that the transverse sealing device 450 is usually operated only once at the beginning of the process, and the bottom of the continuous plastic reaction bag is sealed.

[0204] In one embodiment, the edge sealing device 440 comprises two rolling heat sealing assemblies arranged oppositely.

[0205] The rolling heat sealing assembly comprises a driving wheel 441, a driven wheel 442 and a conveyor belt 443 wound around the two, at least one of the driving wheel 441 and the driven wheel 442 is provided with a heating element and is used to continuously pull and heat seal the side edges of the transparent plastic film 2 after being attached.

[0206] The method increases the limited distance of the edge sealing device 440 to the transparent plastic film 2 (plastic reaction bag) for pulling and conveying, thereby improving the conveying stability and reliability of the transparent plastic film 2 (plastic reaction bag), providing a stable environment for filling, and further ensuring the stable and reliable filling. And the heating element transmits heat to the conveyor belt 443 through the driving wheel 441 or the driven wheel 442, increasing the heat sealing distance, further improving the edge sealing firmness, and further improving the quality of the continuous reaction bag, providing a basis for realizing continuous filling.

[0207] Preferably, one of the driving wheel 441 and the driven wheel 442 close to the film clamping device 430 is provided with a heating element, thereby improving the edge sealing efficiency, that is, by forming a continuous plastic reaction bag as soon as possible, thereby ensuring the safety of filling.

[0208] In one embodiment, the filling pipe 410 is vertically arranged, and the filling direction is the direction of gravity.

[0209] In one embodiment, the end of the filling pipe 410 is located at the horizontal plane of the feeding port of the film clamping device 430.

[0210] The embodiment of the present application realizes the closed and continuous preparation of the polymer water-absorbing resin gel at normal temperature and pressure, that is, without the use of heating equipment or pressurizing equipment, thereby reducing the equipment cost, further reducing the manufacturing cost, and improving the safety of the preparation process. At the same time, the closed preparation has no harmful gas emission to the outside, and no treatment equipment is needed, realizing environmental protection while further controlling the preparation cost. In addition, the continuous preparation production improves the preparation efficiency and preparation scale, further reducing the preparation cost.

[0211] Three specific examples are given below to specifically illustrate the technical effect of the controllable polymerization reaction of the present application.

[0212] Example 1:

[0213] Step 1, preparation of reaction solution: neutralize acrylic acid with alkali to prepare a sodium acrylate aqueous solution with a neutralization degree of 60%, and control the temperature at 5°C. The amount of the reaction solution can meet the needs of subsequent continuous filling and continuous polymerization; wherein the neutralization solution is the reaction solution of this embodiment 1;

[0214] Step 2, continuously filling and forming a first preform 1 with continuous output: continuously filling the neutralized solution into the transparent PE film tube to form a continuous first preform 1, and controlling the width of the first preform 1 to be 1000 mm and the thickness to be 120 mm;

[0215] Step 3, continuous polymerization reaction: placing the first preform 1 under the irradiation of a UV light source with a wavelength of 385 nm and an intensity of 20 mW / cm2for 90 min, so that the neutralized solution undergoes a polymerization reaction to generate a high molecular water-absorbing resin gel, wherein the first preform 1 is turned over every 30 min.

[0216] The high molecular water-absorbing resin gel is subjected to processes such as shearing, drying, and surface treatment, and a final high molecular water-absorbing resin product is prepared.

[0217] According to GB / T22875-2018, it is found that:

[0218]

[0219] As can be seen from the above table, the water-absorbing resin prepared in Example 1 meets the standard indicators, especially the residual monomer indicator far exceeds the standard indicator.

[0220] Example 2:

[0221] Step 1, preparing a reaction solution: preparing a potassium acrylate aqueous solution with a neutralization degree of 80% by adding potassium hydroxide to acrylic acid, and controlling the temperature of the reaction solution to be 0°C;

[0222] Step 2, continuously filling and forming a first preform 1 with continuous output: continuously filling the reaction solution into the transparent PE film tube to form a continuous first preform 1, and controlling the width of the first preform 1 to be 1000 mm and the thickness to be 100 mm;

[0223] Step 3, continuous polymerization reaction: synchronously sending the first preform 1 to the polymerization reaction area with the filling, and placing it under the irradiation of a UV light source with a wavelength of 320 nm and an intensity of 15 mW / cm2for 120 min, so that the neutralized solution undergoes a polymerization reaction to generate a high molecular water-absorbing resin gel, wherein the first preform 1 is turned over every 40 min. The high molecular water-absorbing resin gel is subjected to processes such as shearing, drying, and surface treatment, and a final high molecular water-absorbing resin product is prepared.

[0224] Example 2 is based on Example 1, and the starting temperature of the reaction solution is reduced and the neutralization degree is increased. At the same time, the wavelength of the UV light is reduced and the UV light intensity is reduced, and the second length of time for turning over and the total irradiation length of time are increased.

[0225] According to GB / T22875-2018, it is found that:

[0226]

[0227] From the above table, the indicators of the water-absorbing resin product prepared in Example 2 all meet the standard indicators, and the residual monomer is further improved compared to Example 1. At the same time, the absorption capacity, water retention capacity and pressurized absorption capacity also exceed the standard indicators, especially the residual monomer indicator far exceeds the standard indicators and similar products in the prior art.

[0228] Example 3:

[0229] Step 1, preparation of reaction solution: sodium hydroxide neutralization degree of 75% of acrylic acid sodium aqueous solution and acrylamide are added to prepare the reaction solution, and the temperature is controlled at -3℃;

[0230] Step 2, continuous filling and forming a continuous output of the first preform 1: continuously fill the reaction solution into the transparent PE film tube to form a continuous first preform 1, control the width of the first preform 1 to be 1000mm and the thickness to be 60mm;

[0231] Step 3, continuous polymerization reaction: the first preform 1 is sent into the polymerization reaction zone at the same time of filling, and is placed under the irradiation of UV light source with wavelength of 360nm and intensity of 10mW / cm2 for 150min, so that the neutralization solution generates polymerization reaction to generate high molecular water-absorbing resin gel, wherein it is turned over every 30min. The high molecular water-absorbing resin gel is subjected to shearing, drying, surface treatment and other processes to obtain the final high molecular water-absorbing resin product.

[0232] Among them, compared with Example 2, the starting temperature of the reaction solution is further reduced, and the neutralization degree is controlled within a reasonable range; at the same time, the wavelength of UV light is set to 360nm and the intensity is set to 10mW / cm2, the second length of time for turning over is reduced, the turning over frequency is increased, and the total irradiation time is further increased.

[0233] According to GB / T22875-2018, the following results are obtained:

[0234]

[0235] From the above table, the indicators of the high molecular water-absorbing resin product prepared in Example 3 are further improved based on Example 2, and all exceed the current standard indicators, especially the residual monomer indicator is further optimized.

[0236] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims

1. A method for continuously and sealed preparation of superabsorbent polymers at room temperature and pressure, characterized in that, The filling module, the packaging module, the first conveying module and the polymerization module are sequentially connected; The filling module comprises a feeding port and a continuous feeding assembly connected with the feeding port; The continuous feeding assembly continuously outputs the reaction liquid through the feeding port, and the reaction liquid comprises a polymerization monomer solution; The packaging module comprises an automatic bag making mechanism butting against the feeding port and a continuous film feeding assembly connected with the automatic bag making mechanism; The automatic bag making mechanism is used for continuously packaging the transparent plastic film provided by the continuous film feeding assembly into a continuous plastic reaction bag; The preparation steps comprise: S1, using the packaging module to prepare a plastic reaction bag with a bottom and side edge sealed and continuously produced, and simultaneously filling the reaction liquid into the plastic reaction bag through the feeding port of the filling module to fill the plastic reaction bag and discharge the gas in the plastic reaction bag to form a first preform continuously output; S2, using the first conveying module to butt against the first preform and continuously conveying to the polymerization module at the output rate of the first preform; S3, the polymerization module continuously irradiates the first preform with UV light, the UV light is used for UV radiation polymerization of the reaction liquid, and continuously provides energy for the polymerization reaction, so that the reaction liquid continuously and controllably polymerizes in the sealed state of the plastic reaction bag to form a water absorbing resin gel; The polymerization module comprises a second conveying module butting against the first conveying module and a UV light irradiation device oppositely and spaced apart from the second conveying module; The second conveying module receives the first preform of the first conveying module and uniformly conveys the first preform; The light irradiation device forms stable UV light irradiation towards the surface of the second conveying module; Step S3 comprises: S31, irradiating the first preform with UV light for a first time length, so that the fluidity of the reaction liquid in the first preform decreases to a first threshold value; S32, turning over the first preform upside down so that the bottom surface of the first preform faces the light irradiation device; S33, repeating the step S32 every second time length until the water absorbing resin gel is formed; The second conveying module comprises a plurality of conveying belts spaced apart and horizontally arranged in the thickness direction, and a turnover mechanism connecting adjacent two conveying belts; The turnover mechanism comprises oppositely arranged first and second turnover belts, and a turnover channel is formed between the first and second turnover belts; At the entrance of the turnover channel, the first turnover belt butts against the lower conveying belt, and the turnover channel is bent in the thickness direction, so that at the outlet of the turnover channel, the second turnover belt butts against the upper conveying belt; and the turnover channel can clasp and fix the first preform to prevent the first preform from sliding in the turnover channel; Above each conveying belt, a light irradiation device is correspondingly arranged; The step S32 comprises: When the first preform is conveyed to the end of the conveying belt, the first and second turnover belts clasp the first preform into the turnover channel; The turnover channel drives the first preform to turn over and transfers the turned over first preform to the upper conveying belt.

2. The method of claim 1, wherein the method is a continuous method at room temperature and normal pressure. The reaction solution is an aqueous solution of homopolymer or copolymer monomers of hydrophilic polymers, including acrylic acid monomers, acrylic acid salt monomers or acrylamide monomers, and the initial temperature of the reaction solution is -10-25℃.

3. The method for preparing superabsorbent polymers in a continuous, closed-loop manner at room temperature and pressure according to claim 1, characterized in that, The wavelength of the UV light used in the polymerization module is 320-400 nm, and the intensity is 1-30 mW / cm2.

4. The method of claim 1, wherein the method is a continuous method at room temperature and normal pressure. The first transmission module is a horizontal conveying belt. The step S2 includes: The starting end of the first preform naturally slides down to the surface of the conveying belt under the action of gravity. The conveying belt drives the first preform towards the polymerization module and makes the first preform lay flat on the surface of the conveying belt, and the thickness of the first preform is 50-150 mm.

5. The method of claim 1, wherein the method is characterized by the steps of: continuously preparing the polymer water-absorbing resin at room temperature and normal pressure in a closed system. The first time length is 5-100 min, and the second time length is 5-60 min. In the step S33, the number of times of repeating the step S32 is 1-8.

6. The method of claim 1, wherein the method is a continuous method at room temperature and normal pressure. The continuous feeding assembly includes a plurality of storage tanks for storing reaction solution. The plurality of storage tanks are connected to the feeding port and sequentially feed the feeding port. The process of continuously outputting reaction solution includes: when the capacity of the reaction solution in the previous storage tank decreases to a set value, the next storage tank starts to feed the feeding port, so that the two storage tanks feed the feeding port at the same time until the reaction solution in the previous storage tank is exhausted. The exhausted storage tank is replenished with solution to ensure continuous feeding of the feeding port.

7. The method of claim 1, wherein the method is a continuous method at room temperature and normal pressure. The transparent plastic film provided by the continuous film supply assembly is a transparent plastic film, and a strip-shaped transparent plastic film is continuously provided, the transparent plastic film includes a first edge and a second edge along the conveying direction. The automatic bag making mechanism includes a plurality of edge sealing devices arranged along the forming direction of the plastic reaction bag. The first edge and the second edge of the transparent plastic film overlap after wrapping the feeding port and enter the plurality of edge sealing devices, and any one of the plurality of edge sealing devices heat seals the first edge and the second edge.

8. The method for continuously preparing polymer water-absorbing resin at room temperature and pressure in a closed system according to claim 1, characterized in that: The continuous film supply assembly includes a plurality of film supply rolls, a connecting device and a buffer device. Any one of the plurality of film supply rolls connects the transparent plastic film to the connecting device and the buffer device in sequence. The discharge port of the buffer device guides the transparent plastic film to the automatic bag making mechanism, the buffer device is used to buffer the transparent plastic film of a first length, and when the film supply roll stops supplying film, the buffer device can continue to provide the transparent plastic film of the first length. The continuous supply step of the transparent plastic film includes: The transparent plastic film of any one of the plurality of film supply rolls is sequentially conveyed to the connecting device and the buffer device, and the buffer device starts to store the transparent plastic film of the first length. When the transparent plastic film of any one of the film supply rolls is used up, the connecting device clamps the tail end of the transparent plastic film, and the buffer device continues to buffer the transparent plastic film. The first end of the transparent plastic film of any one of the other film supply rolls is connected to the connecting device; The connecting device releases the clamping of the transparent plastic film after heat-sealing the tail end of the transparent plastic film and the first end of the other transparent plastic film; At this time, the buffer device starts to store the transparent plastic film until the first length of the transparent plastic film is stored while maintaining the conveying of the transparent plastic film, realizing the continuous supply of the transparent plastic film.

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