Super absorbent polymer drying apparatus

Abstract

A super absorbent polymer drying apparatus is disclosed. The super absorbent polymer drying apparatus is a drying apparatus equipped with a conveyor (100) for drying the super absorbent polymer (12), and may include: a conveyor for transferring the super absorbent polymer; and a hot air supply part (200) for supplying dry hot air to the conveyor, wherein the conveyor may include a plurality of conveyor beds (110) connected to each other in a bent state, a link connecting part (115) for connecting between the plurality of conveyor beds, and a driving part (120) for driving the conveyor beds.

Description

Superabsorbent resin drying device

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority to Republic of Korea Patent Application No. 10-2020-0138510, dated October 23, 2020, the entire contents of which are incorporated herein by reference.

[0003]

[0004] The present invention relates to a superabsorbent resin drying device that improves the drying efficiency of superabsorbent resin.

[0005]

[0006] Generally, super absorbent polymer (SAP) is a white powder-like polymer material manufactured by reacting acrylic acid and caustic soda, and can absorb 500 to 1,000 times its own weight in moisture.

[0007] Superabsorbent polymer is a synthetic polymer material that transforms into a jelly-like form when it absorbs water and has the ability to store water without releasing it even when a certain amount of pressure is applied from the outside.

[0008] Superabsorbent polymer molecules have a network-like structure, and because of the many pores between them, they can absorb water well, and because of the difference in ion concentration between the inside of the superabsorbent polymer and the external solution (water), water moves into the inside of the superabsorbent polymer (osmotic pressure phenomenon). When water molecules flow into the inside of the superabsorbent polymer, the anions fixed inside try to occupy a certain space due to repulsion, and the space in the polymer chain expands, allowing more water to be absorbed (electrostatic repulsion).

[0009] These superabsorbent resins began to be put to practical use as sanitary products, and are now widely used in various fields, including sanitary products such as children's paper diapers, as soil conditioners for gardening, water-retaining materials for civil engineering and construction, seedling sheets, and as freshness-maintaining agents in the food distribution industry, as well as for steaming.

[0010] Known methods for manufacturing superabsorbent resins include a method using reverse phase suspension polymerization or a method using aqueous solution polymerization.

[0011] Among these, known methods using aqueous solution polymerization include a thermal polymerization method in which a polymer gel is broken and cooled while polymerizing in a kneader equipped with a shaft, and a photopolymerization method in which polymerization and drying are simultaneously performed by irradiating a high-concentration aqueous solution on a belt with ultraviolet rays, etc.

[0012] As a previously known method, there is a method for producing an absorbent resin in which a water-soluble ethylenically unsaturated monomer having a crosslinking agent is polymerized by irradiating it with ultraviolet rays in the presence of a radical photopolymerization initiator having a benzoyl group and a peroxide, and the absorbent resin produced through this polymerization reaction is manufactured into a powdered absorbent resin through processes such as cutting, drying, grinding, and surface treatment.

[0013] Among these, the drying process transfers the absorbent resin to a dryer via a conveyor belt, and the resin is dried into a sheet-shaped lump by being laminated to a thickness of approximately 100 mm on the conveyor belt.

[0014] In the drying process, the superabsorbent resin before drying has low bonding strength between superabsorbent resins, so the particles are easily separated, but the superabsorbent resin after drying has a solid structure as the particles bond to each other.

[0015] Meanwhile, conventional conveyor belts are installed in a flat state and perform drying operations of superabsorbent resins, which limits the drying amount during the drying process and thus has the problem of limiting drying efficiency.

[0016]

[0017] One embodiment of the present invention provides a super absorbent resin drying device capable of increasing the contact area of ​​hot air by installing a conveyor at an angle, thereby increasing the drying amount and improving the drying efficiency.

[0018]

[0019] One embodiment of the present invention is a drying device having a conveyor installed for drying a superabsorbent resin, which may include a conveyor for transporting the superabsorbent resin and a hot air supply unit for supplying drying hot air to the conveyor.

[0020] The conveyor may include a plurality of conveyor beds that are connected to each other in a curved state, a link connecting portion connecting between the plurality of conveyor beds, and a driving portion that drives the conveyor beds.

[0021] The conveyor bed may include a plurality of bed bodies on which a superabsorbent resin is deposited on the surface and transported, and a connecting groove formed on the side of the bed body to which the link connecting portion is connected.

[0022] The link connecting portion may include a link protrusion protruding from one side of the bed body and inserted into a connecting groove of an adjacent bed body.

[0023] The plurality of bed bodies can be connected at an angle ranging from 90 degrees to 170 degrees to each other.

[0024] The driving unit may include a rack gear installed along the edge of the bed body and a pinion gear meshed with the rack gear to provide a moving driving force to the bed body.

[0025] The rack gear may include a first rack gear installed along an edge of the upper surface of the bed body and a second rack gear installed along an edge of the lower surface of the bed body.

[0026] The pinion gear may include a first pinion gear that transmits rotational driving force to a first rack gear on the upper side of the bed body, and a second pinion gear that transmits rotational driving force to a second rack gear on the lower side of the bed body.

[0027] The first pinion gear can be engaged with the first rack gear at an upper side of a position where the plurality of bed bodies are connected at an angle to each other.

[0028] The second pinion gear can be engaged with the second rack gear at the lower side of the position where the plurality of bed bodies are connected at an angle to each other.

[0029]

[0030] According to one embodiment of the present invention, a plurality of bed bodies constituting a conveyor are connected to each other at an angle and operated by a driving force of a driving unit, so that the contact area of ​​hot air supplied to the conveyor is increased and the thickness of the crumb bed can be reduced, thereby improving the drying efficiency of a superabsorbent resin.

[0031]

[0032] FIG. 1 is a schematic diagram of a superabsorbent resin drying device according to one embodiment of the present invention.

[0033] Fig. 2 is a schematic plan view of a portion of the conveyor bed of Fig. 1 in which multiple bed bodies are connected.

[0034] Fig. 3 is a schematic plan view of a portion of the bed body of Fig. 2 separated.

[0035] Figure 4 is a cross-sectional view schematically illustrating the bed body taken along line AA of Figure 3.

[0036]

[0037] <Explanation of symbols>

[0038] 11...Dryer body

[0039] 12...Superabsorbent resin

[0040] 13...Input section

[0041] 100..Conveyor

[0042] 110..Conveyor bed

[0043] 111..bed body

[0044] 113..Connection Home

[0045] 115..link connection, link protrusion

[0046] 120..link connection

[0047] 121..Rack gear

[0048] 121a..1st rack gear

[0049] 121b..2nd rack gear

[0050] 123..pinion gear

[0051] 123a..1st pinion gear

[0052] 123b..2nd pinion gear

[0053] 200..Hot air supply department

[0054]

[0055] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts irrelevant to the description have been omitted to clearly explain the present invention, and the same reference numerals have been used throughout the specification to refer to identical or similar components.

[0056]

[0057] FIG. 1 is a schematic drawing of a superabsorbent resin drying device according to one embodiment of the present invention, FIG. 2 is a schematic plan view of a main part of a conveyor bed of FIG. 1 in a state where multiple bed bodies are connected, FIG. 3 is a schematic plan view of a main part of a bed body of FIG. 2 in a state where a portion of the bed body is separated, and FIG. 4 is a cross-sectional view schematically illustrating a bed body taken along line AA of FIG. 3.

[0058] As illustrated in FIGS. 1 to 4, a superabsorbent resin drying device (300) according to one embodiment of the present invention is a drying device in which a conveyor for drying a superabsorbent resin is installed, and may include a conveyor (100) for transporting a superabsorbent resin (12), and a hot air supply unit (200) for supplying drying hot air to the conveyor (100).

[0059] The conveyor (100) can be installed to receive the superabsorbent resin (12) and transport the superabsorbent resin (12) inside the dryer body (11).

[0060] An input portion (13) for supplying superabsorbent resin (12) to a conveyor (100) may be installed on the side of the dryer body (11).

[0061] The inlet (13) is installed to appropriately inject the superabsorbent resin (12) to be dried from the side of the dryer body (11) toward the conveyor (100). The superabsorbent resin (12) may be installed to be dropped by its own weight onto the conveyor (100) installed inside the dryer body (11).

[0062] The conveyor (100) can be installed so as to be movable in one direction or reverse by the driving operation of the driving unit (120) inside the dryer body (11), so that the superabsorbent resin (12) can be dried by hot air supplied through the hot air supply unit (200).

[0063] A plurality of hot air supply units (200) may be installed at the bottom of the conveyor (100) to supply hot air for drying to the conveyor (100).

[0064] To be more specific, the conveyor (100) may include a plurality of conveyor beds (110) that are connected to each other in a curved state, a link connecting portion (115) connecting between the plurality of conveyor beds (110), and a driving portion (120) that drives the conveyor beds (110).

[0065] A plurality of conveyor beds (110) may be installed in a state in which they are adjacent to each other and connected to each other. The conveyor beds (110) may be installed in a state in which they are connected to each other at an angle and are movable by the driving force of the driving unit (120) within the dryer body (11).

[0066] Such a conveyor bed (110) may include a plurality of bed bodies (111) on which a superabsorbent resin (12) is transported by being settled on the surface, and a connecting groove (113) formed on the side of the bed body (111) to which a link connecting portion (115) is connected.

[0067] The bed body (111) has a rectangular flat shape, and a plurality of bed bodies can be connected to each other by link connecting parts (115) in an adjacent state.

[0068] A bed body (111) may have a connecting groove (113) formed on one side to which a link connecting portion (115) is connected so that a plurality of bed bodies (111) are connected to each other in an adjacent state.

[0069] The connecting home (113) is formed in multiple numbers on one side of the bed body (111), and can be formed so that a link connecting part (115) formed on the side of any one of the adjacent bed bodies (111) among the multiple bed bodies (111) is connected.

[0070] These connecting grooves (113) are formed in two pieces spaced apart from each other on one side of the bed body (111), and can be connected with the link connecting part (115) inserted inside.

[0071] The link connecting portion (115) is formed by protruding on a side opposite to the side where the connecting groove (113) is formed in the bed body (111), and in this embodiment, it can be applied as a link protrusion that is connected while being inserted into the inside of the connecting groove (113). Hereinafter, the link connecting portion and the link protrusion use the same reference numbers.

[0072] The link protrusions (115) are two protruding from the side of the bed body (111) in a spaced-apart manner, and can be inserted and fixed into a connecting groove (113) formed in an adjacent bed body (111) when a plurality of bed bodies (111) are arranged adjacent to each other.

[0073] Here, a plurality of bed bodies (111) can be connected to each other at an angle ranging from 90 degrees to 170 degrees (A).

[0074] A plurality of bed bodies (111) can be installed at an angle of 5 to 45 degrees upwardly within the dryer body (11). In addition, a plurality of bed bodies (111) can be connected to each other at an angle of 90 to 170 degrees.

[0075] When viewed from the side, these multiple bed bodies (111) can be connected to each other in a zigzag shape in the upper and lower directions.

[0076] In this way, the conveyor (100) of the present embodiment has a plurality of bed bodies (111) connected to each other at an angle, so that the surface area where the superabsorbent resin is settled in the internal space of the dryer body (11) can be increased by 12% or more compared to a conventional flat conveyor.

[0077] That is, when the plurality of bed bodies (111) of the present embodiment are connected at an angle of 90 to 170 degrees relative to each other in comparison with a conventional 1 m flat conveyor, the connected length can be extended to 1.12 m. Accordingly, the thickness of the crumb bed installed on the upper surface of the bed body (111) can be reduced by 12%. The area with which hot air comes into contact can be increased by 12%, thereby improving the drying efficiency of the superabsorbent resin.

[0078] Meanwhile, the driving unit (120) can be installed movably inside the dryer body (11) in a state where a plurality of bed bodies (111) are connected to each other by link protrusions (115).

[0079] To be more specific, the driving unit (120) may include a rack gear (121) installed along the edge of the bed body (111), and a pinion gear (123) that meshes with the rack gear (121) to provide a moving driving force to the bed body (111).

[0080] The rack gear (121) may include a first rack gear (121a) installed along the edge of the upper surface of the bed body (111) and a second rack gear (121b) installed along the edge of the lower surface of the bed body (111).

[0081] The first rack gear (121a) can be installed at opposite edge positions on the upper surface of a plurality of bed bodies (111).

[0082] The second rack gear (121b) can be installed at opposite edge positions on the lower surface of a plurality of bed bodies (111).

[0083] A pinion gear (123) can be meshed with the first rack gear (121a) and the second rack gear (121b).

[0084] The pinion gear (123) may include a first pinion gear (123a) that transmits rotational driving force to a first rack gear (121a) on the upper side of the bed body (111), and a second pinion gear (123b) that transmits rotational driving force to a second rack gear (121b) on the lower side of the bed body (111).

[0085] The first pinion gear (123a) can be installed so as to mesh with the first rack gear (121a) on the upper side where a plurality of bed bodies (111) are connected to each other.

[0086] This first pinion gear (123a) can be installed in a state of meshing with the first rack gear (121a) at a position where the plurality of bed bodies (111) are connected to each other. Accordingly, the first pinion gear (123a) can transmit driving force to the conveyor (100) while supporting the upper side where the plurality of bed bodies (111) are connected to each other.

[0087] The first pinion gear (123a) is installed in multiple numbers to support the upper positions where multiple bed bodies (111) are connected to each other, and can be installed to support the upper positions where multiple bed bodies (111) are connected at an angle.

[0088] The second pinion gear (123b) can be installed so as to mesh with the second rack gear (121b) at the lower side where the plurality of bed bodies (111) are connected to each other.

[0089] This second pinion gear (123b) can be installed in a state of meshing with the second rack gear (121b) at a position where the plurality of bed bodies (111) are connected to each other. Accordingly, the second pinion gear (123b) can transmit driving force to the conveyor (100) while supporting the lower side where the plurality of bed bodies (111) are connected to each other.

[0090] The second pinion gear (123b) is installed in multiple numbers to support the lower positions where the multiple bed bodies (111) are connected to each other, and can be installed to support the lower positions where the multiple bed bodies (111) are connected at an angle.

[0091] The first pinion gear (123a) and the second pinion gear (123b) described above can be installed at alternate positions so as to support the upper and lower sides of the bed bodies (111) at positions where a plurality of bed bodies (111) are connected.

[0092] In this way, the first pinion gear (123a) and the second pinion gear (123b) can be installed to stably support a state in which a plurality of bed bodies (111) are connected at an angle, while appropriately transmitting driving force to the conveyor (100).

[0093] As described above, the superabsorbent resin drying device (300) of the present embodiment is operated by the driving force of the driving unit (120) in which a plurality of bed bodies (111) constituting the conveyor (100) are connected to each other at an angle, so that the contact area of ​​the hot air supplied to the conveyor (100) increases and the thickness of the crumb bed can be reduced, thereby improving the drying efficiency of the superabsorbent resin.

[0094]

[0095] The superabsorbent resin referred to in the present invention may be manufactured by conventional methods and is not particularly limited. For example, the superabsorbent resin may be polymerized by thermal polymerization or photopolymerization of a monomer composition solution containing raw materials for the superabsorbent resin.

[0096] The raw materials of the superabsorbent resin may include a monomer, a basic compound for neutralizing the monomer, a polymerization initiator, a crosslinking agent, and various additives.

[0097] The monomer may be used without limitation in its composition as long as it is a monomer commonly used in the production of superabsorbent resins. At least one selected from the group consisting of anionic monomers and their salts, nonionic hydrophilic monomers, and amino group-containing unsaturated monomers and their quaternary compounds may be used.

[0098] Specifically, anionic monomers and salts thereof of (meth)acrylic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethane sulfonic acid, 2-methacryloylethanesulfonic acid, 2-(meth)acryloylpropanesulfonic acid or 2-(meth)acrylamide-2-methyl propane sulfonic acid; nonionic hydrophilic-containing monomers of (meth)acrylamide, N-substituted (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate or polyethylene glycol (meth)acrylate; And at least one selected from the group consisting of amino group-containing unsaturated monomers such as (N,N)-dimethylaminoethyl(meth)acrylate or (N,N)-dimethylaminopropyl(meth)acrylamide and quaternary compounds thereof can be preferably used.

[0099] Monomer concentration can be appropriately selected and used by considering polymerization time, reaction conditions, etc.

[0100] The monomer composition solution contains a polymerization initiator, which may include a photopolymerization initiator when ultraviolet rays are irradiated from the polymerization energy supply unit, or a thermal polymerization initiator when hot air is supplied.

[0101] As a thermal polymerization initiator, one or more selected from the group of initiators consisting of a persulfate initiator, an azo initiator, hydrogen peroxide, and ascorbic acid can be used. Specifically, examples of persulfate-based initiators include sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), and ammonium persulfate ((NH4)2S2O8), and examples of azo-based initiators include 2, 2-azobis-(2-amidinopropane) dihydrochloride, 2, 2-azobis-(N, N-dimethylene)isobutyramidine dihydrochloride, 2-(carbamoylazo)isobutylonitril, 2, 2-Azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, 4,4-azobis-(4-cyanovaleric acid), etc. can be used. A more diverse range of thermal initiators is well described in Odian's book, "Principle of Polymerization (Wiley, 1981sus)", p203, and is not limited to the examples described above.

[0102] As the photopolymerization initiator, one or more selected from the group consisting of benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, benzyl dimethyl ketal, acyl phosphine, and α-aminoketone can be used. Meanwhile, as a specific example of the acyl phosphine, the commercially available lucirin TPO, i.e., 2,4,6-trimethyl-benzoyl-trimethyl phosphine oxide, can be used. A more detailed description of various photoinitiators, including but not limited to the examples described above, is given in Reinhold Schwalm's book "UV Coatings: Basics, Recent Developments and New Applications (Elsevier 2007)", p.115.

[0103] As the crosslinking agent, one or a combination of two or more selected from diacrylate crosslinking agents including hexanediol diacrylate, ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, propylene glycol diacrylate, dipropylene glycol diacrylate, and tripropylene diacrylate; triacrylate crosslinking agents, aziridine crosslinking agents; and epoxy crosslinking agents may be used.

[0104] The crosslinking agent may be included in an amount of about 0.01 to about 0.5 wt% based on the total content of the monomer composition solution.

[0105] Additives include thickeners, plasticizers, preservatives, and antioxidants.

[0106] These monomers, polymerization initiators, crosslinkers and additives can be prepared in the form of a solution dissolved in a solvent.

[0107] The solvent that can be used at this time can be used without limitation in its composition as long as it can dissolve the above-mentioned components, and for example, one or two or more selected from water, ethanol, ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, propylene glycol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, acetone, methyl amyl ketone, cyclohexanone, cyclopentanone, diethylene glycol monomethyl ether, diethylene glycol ethyl ether, toluene, xylene, butyrolactone, carbitol, methyl cellosolve acetate, and N,N-dimethylacetamide can be used in combination.

[0108] The solvent may be included as a residual amount excluding the above-described components in the total content of the composition solution.

[0109] Polymerization methods are largely divided into thermal polymerization and photopolymerization depending on the polymerization energy source. When thermal polymerization is usually performed, it can be performed in a reactor with a stirring shaft such as a kneader, and when photopolymerization is performed, it can be performed in a reactor with a movable conveyor belt or in a flat-bottomed container. However, the above-described polymerization method is an example, and the present invention is not limited to the above-described polymerization method.

[0110] For example, a hydrogel polymer obtained by thermal polymerization by supplying hot air or heating a reactor such as a kneader equipped with a stirring shaft as described above may have a size of several centimeters to several millimeters when discharged from the reactor outlet, depending on the shape of the stirring shaft equipped in the reactor. Specifically, the size of the obtained hydrogel polymer may vary depending on the concentration and injection speed of the injected monomer composition, and typically, a hydrogel polymer having a weight average particle diameter of 2 to 50 mm can be obtained.

[0111] In addition, when photopolymerization is performed in a reactor equipped with a movable conveyor belt as described above or in a flat-bottomed container, the form of the hydrogel polymer typically obtained may be a sheet-shaped hydrogel polymer having the width of the belt. At this time, the thickness of the polymer sheet varies depending on the concentration and injection speed or injection amount of the injected monomer composition, but it is preferred to supply the monomer composition so that a sheet-shaped polymer having a thickness of about 0.5 to about 5 cm can be obtained. If the monomer composition is supplied so that the thickness of the sheet-shaped polymer is excessively thin, the production efficiency is low, which is not preferred, and if the thickness of the sheet-shaped polymer exceeds 5 cm, the polymerization reaction may not occur evenly across the entire thickness due to the excessive thickness.

[0112] At this time, the typical moisture content of the hydrogel polymer obtained by this method may be about 40 to about 80 wt%. Meanwhile, throughout the present specification, "moisture content" refers to the content of moisture in relation to the total weight of the hydrogel polymer, which is the value obtained by subtracting the weight of the polymer in a dry state from the weight of the hydrogel polymer. Specifically, it is defined as a value calculated by measuring the weight loss due to moisture evaporation in the polymer during the process of drying by raising the temperature of the polymer through infrared heating. At this time, the drying conditions are such that the temperature is raised from room temperature to about 180°C and then maintained at 180°C, and the total drying time is set to 20 minutes, including 5 minutes of the temperature rising step, to measure the moisture content.

[0113] Thereafter, when drying the obtained functional gel polymer, the superabsorbent resin drying device of the present invention can be used.

[0114]

[0115] Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications can be made within the scope of the claims, the detailed description of the invention, and the attached drawings, and it is obvious that this also falls within the scope of the present invention.

Claims

1. A drying device equipped with a conveyor for drying superabsorbent resin, A conveyor for transporting the above superabsorbent resin; and A hot air supply unit that supplies drying hot air to the above conveyor; Including, The above conveyor, A plurality of conveyor beds connected to each other in a curved manner; A link connecting portion connecting between the plurality of conveyor beds; and A driving unit for driving the above conveyor beds; A super absorbent resin drying device comprising:

2. In paragraph 1, The above conveyor bed, A plurality of bed bodies on which the superabsorbent resin is transported while being settled on the surface; and A connecting groove formed on the side of the bed body to which the link connecting portion is connected; A superabsorbent resin drying device comprising:

3. In paragraph 2, The above link connection part is, A super absorbent resin drying device comprising a link protrusion protruding from one side of the bed body and inserted into the connecting groove of the adjacent bed body.

4. In paragraph 3, A super absorbent resin drying device in which the above plurality of bed bodies are connected at an angle of 90 to 170 degrees to each other.

5. In paragraph 4, The above driving part, A rack gear installed along the edge of the above bed body; and A pinion gear that meshes with the above rack gear and provides a driving force to the bed body; A super absorbent resin drying device comprising:

6. In paragraph 5, The above rack gear is, A first rack gear installed along the edge of the upper surface of the bed body; and A second rack gear installed along the edge of the lower surface of the bed body; A super absorbent resin drying device comprising:

7. In paragraph 6, The above pinion gear, A first pinion gear that transmits rotational driving force to the first rack gear on the upper side of the bed body; and A second pinion gear that transmits rotational driving force to the second rack gear at the lower side of the bed body; A super absorbent resin drying device comprising:

8. In paragraph 7, The above first pinion gear, A super absorbent resin drying device in which the plurality of bed bodies are connected to each other at an inclined position and are engaged with the first rack gear at the upper side.

9. In paragraph 8, The above second pinion gear, A super absorbent resin drying device in which the plurality of bed bodies are connected to each other at an inclined angle and are engaged with the second rack gear at the lower side.