JP2009018239A - Method of manufacturing spiral liquid separation element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a leak-free spiral liquid separation element by using a high-performance reverse osmosis membrane. <P>SOLUTION: The method comprises manufacturing a spiral liquid separation element 29 by winding a permeate passage material 20, a reverse osmosis membrane 8, a raw liquid passage material 9 and another reverse osmosis membrane 8, in this order in a superimposed form, around a hollow central tube 34 having holes in the surface. In applying an adhesive to adhere the three circumferential edges of the reverse osmosis membrane 8, the permeate passage material 20 and the another reverse osmosis membrane 8 together, the adhesive-applied part 28 of the reverse osmosis membrane yet in a wet state before subsequent application of the adhesive is dried, and then the adhesive is applied for adhesion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a spiral liquid separation element using a reverse osmosis membrane and a reverse osmosis membrane drying apparatus.

  The spiral type liquid separation element is basically composed of a hollow central tube, a reverse osmosis membrane surrounding the hollow central tube, a permeate channel material, and a raw solution channel material. Usually, a liquid separation element having such a structure is a reverse osmosis membrane unit with a raw liquid flow path material sandwiched between reverse osmosis membranes, and this unit and permeate flow path material are alternately stacked and bonded with an adhesive. It is manufactured by joining and enclosing it around a central tube after forming an envelope so that one side becomes a liquid flow path. Here, the separation performance of the spiral type liquid separation element is not limited to the fact that there is no defect in the reverse osmosis membrane, but also depends on the adhesiveness of the adhesive applied to the permeate channel material. It depends on the adhesive width and adhesive viscosity of the agent.

  In addition, as a required characteristic of a spiral liquid separation element using a reverse osmosis membrane, there is no elution of ionic substances and all organic carbon (TOC) components from the liquid separation element and separation of fine particles and the like as well as separation performance. It is emphasized. In order to satisfy these characteristics, the member in contact with the permeated liquid in the liquid separation element needs to be made of a material with very little elution of ionic substances and TOC components, and a structure in which fine particles do not fall off.

  The reverse osmosis membrane used for manufacturing the spiral liquid separation element needs to be held in a wet state in order to maintain the separation performance. However, when a urethane adhesive is applied and bonded, the isocyanate reacts with water to generate carbon dioxide, which causes foaming and leakage due to insufficient sealing. There is a problem of losing. In order to avoid this problem, the adhesive may be applied after the reverse osmosis membrane is dried.

However, once the reverse osmosis membrane is dried, there is a problem that the separation performance is not restored even if it is returned to a wet state before use. In order to obtain a dry membrane, the reverse osmosis membrane is an aqueous solution of a polyhydric alcohol such as glycerin. It is necessary to dry the film after the immersion treatment in order to form a dry film (see Patent Documents 1 and 2). Therefore, conventionally, when the adhesive-treated portion is dried, the adhesive-treated portion is treated with a glycerin aqueous solution and then dried, and an adhesive is applied to the dried film. According to this method, foaming due to the adhesive can be suppressed even if urethane adhesive is applied, but elution of the TOC component from the reverse osmosis membrane is unavoidable, and it is necessary to wash for a long time before use. Met. This has led to a decrease in the yield of water, which in turn has increased the production cost of pure water.
JP 58-156307 A JP 2000-271451 A

  An object of the present invention is to provide a method capable of producing a leak-free spiral liquid separation element using a high-performance reverse osmosis membrane in producing the spiral liquid separation element as described above.

In order to solve the above problems, the method of the present invention is specified as the following (1) to (8).
(1) A spiral liquid separation element is formed by winding a permeate channel material, a reverse osmosis membrane, a raw solution channel material, and a reverse osmosis membrane in a state of being sequentially stacked around a hollow central tube having a hole on the surface. In the method of manufacturing the reverse osmosis membrane, the flow path material, and the adhesive application portion of the reverse osmosis membrane in a wet state before applying the adhesive when applying the adhesive to adhere the three sides around the reverse osmosis membrane A method for producing a spiral liquid separation element, comprising drying an adhesive and then applying an adhesive.
(2) The method of drying the adhesive-applied portion of the reverse osmosis membrane is any one of drying by bringing a heated member into contact, drying by blowing hot air, and drying by applying light. Alternatively, the method of manufacturing a spiral liquid separation element according to (1) above, which is a combination thereof.
(3) The method for producing a spiral liquid separation element as described in (2) above, wherein the drying by applying light is drying by irradiation with light from a halogen heater.
(4) The adhesive is a urethane-based adhesive, and the main component isocyanate and the curing agent polyol are mixed in a weight ratio of isocyanate: polyol = 1: 1 to 1: 5. The method for producing a spiral liquid separation element according to any one of the above (1) to (3).
(5) The spiral mold according to any one of (1) to (4) above, wherein the moisture content of the adhesive-applied portion of the reverse osmosis membrane is dried to be 10% or less when the adhesive is applied. A method for manufacturing a liquid separation element.
(6) The reverse osmosis membrane is a reverse osmosis membrane having a laminated structure including a base material layer and a reverse osmosis functional thin film layer, wherein the adhesive application portion is dried from the surface on the base material layer side. The manufacturing method of the spiral type liquid separation element in any one of said (1)-(5) to do.
(7) The method for producing a spiral liquid separation element according to any one of the above (1) to (6), wherein the adhesive has a viscosity of 40 PS to 150 PS.
(8) The method for producing a spiral liquid separation element according to any one of (1) to (7), wherein the adhesive width of the adhesive-applied portion of the reverse osmosis membrane is in the range of 5 mm to 80 mm.

  According to the method for manufacturing a spiral liquid separation element of the present invention, only the adhesive-coated portion is dried even when a wet osmosis reverse osmosis membrane in which elution of ionic substances and TOC components is extremely small and fine particles do not fall off is used. By doing so, leakage due to foaming of the adhesive is suppressed, and a liquid separation element having high separation performance and high quality can be obtained.

  Hereinafter, embodiments of the method of the present invention will be described in detail with reference to the drawings.

  FIGS. 1A to 1F are schematic views of a manufacturing flow illustrating a step of laminating a reverse osmosis membrane unit and a permeate flow channel material according to the method of the present invention in a step of manufacturing a spiral liquid separation element. It is. FIG. 2 is a schematic configuration side view showing a stage before the objects stacked in FIG. 1 are wound around the water collecting pipe. FIG. 3 is a schematic side view showing the winding process. FIG. 4 is a partially cutaway perspective view showing an example of a spiral type liquid separation element manufactured in this manner.

  First, as shown in FIG. 1 (a), the reverse osmosis membrane is pulled out on a work table (not shown) from the reverse osmosis membrane roll 1 wound in a roll shape (unwinding step). The drawn reverse osmosis membrane is cut into a predetermined length by the cutter 6 to obtain a sheet-like reverse osmosis membrane 8. The sheet-like reverse osmosis membrane 8 is folded in half so that the functional layer side is on the inside, and placed on a work table (not shown).

  Next, as shown in FIG. 1 (b), the stock solution channel material is unwound from the stock solution channel material roll 10, and then cut into a fixed length by a cutter 11 to obtain a sheet-like stock solution channel material 9. The This stock solution channel material 9 is sandwiched between the sheet-like separation membranes 8 to form a reverse osmosis membrane unit 14 shown in FIG. On the other hand, as shown in FIG. 1 (d), the permeate flow path material unwound from the permeate flow path material roll 19 is cut into a fixed length by a cutter 21, and the sheet-like permeate flow path material 20 and To do.

  The sheet-like permeate passage material 20 is placed on the work table 3. The reverse osmosis membrane unit 14 is overlapped at a predetermined position on the first permeate flow path material 20, and then the second permeate flow path material 20 ′ at a predetermined position on the reverse osmosis membrane unit 14. Repeat. Next, using the adhesive application gun 27 or an adhesive-containing polybag (with one small opening) from above the second permeate channel material 20 ′, the adhesive is removed as shown in FIG. As shown in (plan view), the reverse osmosis membrane unit 14 of the laminated reverse osmosis membrane unit 14 is applied in a U-shape that opens to the double fold side 81.

  When the next reverse osmosis membrane unit 14 'is overlapped after the application of the above-mentioned adhesive, the upper surface of the reverse osmosis membrane in the lower membrane unit, the permeate passage material thereon, and the reverse osmosis membrane thereon Are attached to the lower surface of each of the three sides of the U-shape.

  Next, the permeate passage material 20 ″ is further stacked thereon, the adhesive is applied in the same manner, and the reverse osmosis membrane unit 14 ″ is stacked, and is similarly bonded on the three sides of the U-shape. In the same manner, the permeated liquid channel material 20 is stacked and coated with an adhesive, and the reverse osmosis membrane unit 14 is stacked and bonded a predetermined number of times to form a layered structure as shown in FIG. In this laminated structure, it is preferable that about 4 to 10 reverse osmosis membrane units are arranged.

  Subsequently, the lowermost permeate flow path material 20 in the laminated structure shown in FIG. 2 is bonded to the periphery of the water collecting pipe 34 with a tape or the like, and then, as shown in FIG. The laminated structure 29 is wound around the water collection pipe 34 in a roll shape while being pressed by a pair of nip rolls 44 with an appropriate pressure. In this way, a spiral type liquid separation element having a structure as illustrated in FIG. 4 is obtained.

  In the method of the present invention, it is necessary to dry a portion (including the vicinity thereof) to which the adhesive is applied before applying the adhesive in the above-described process. This drying may be performed in a stage after being cut into a single sheet and before being bent, or may be performed in a stage in which a reverse osmosis membrane unit is formed with a raw material flow path material interposed therebetween.

  The reverse osmosis membrane used in the method of the present invention has been stored in a wet state in order to maintain the separation performance, and the membrane surface portion exhibiting the membrane separation function is used in the production of a liquid separation element while still in a wet state. Is done. Examples of the reverse osmosis membrane include a flat membrane having a separation functional layer made of aromatic polyamide. As the resin constituting the separation functional layer, cellulose acetate, aliphatic polyamide, polyvinyl alcohol, polyethersulfone and the like can be used besides aromatic polyamide.

  Prior to applying the adhesive, the adhesive-applied portion (including the vicinity thereof) of the reverse osmosis membrane stored in a wet state is dried. However, the membrane surface portion that exhibits the separation function is not dried and remains wet. This drying is preferably performed to such an extent that the moisture content of the adhesive application portion is reduced to 10% or less. If the water content exceeds 10%, the main component isocyanate of the urethane-based adhesive reacts with water to generate carbon dioxide, which causes foaming and causes leakage due to insufficient sealing.

  As a method for drying the adhesive-applied portion, a method in which a heated member is brought into contact, hot air is blown, or light is applied is employed. Among these, a drying method of irradiating light heat from a halogen heater is preferably employed because it can be dried in a short time and the drying width can be arbitrarily selected by selecting the irradiation distance. In the case of using a halogen heater, it is preferable to irradiate the surface of the reverse osmosis membrane on the substrate layer side without drying the performance of the ultrathin film layer. Moreover, it is preferable to use a polyester nonwoven fabric or cotton as an underlay for drying the reverse osmosis membrane.

  FIG. 5 shows an example of an apparatus for drying one side of the reverse osmosis membrane with a halogen heater. First, as shown in FIG. 5 ((A) plan view, (B) side view), a wet reverse osmosis membrane 52 cut into a sheet is placed on a flat polyester non-woven cloth underlay 53. . Next, an irradiator 50 having a halogen heater 51 is installed at a predetermined position at a predetermined irradiation distance, and dried by irradiating with photothermal heat. As the halogen heater 51, one having a light emission length of 550 mm, a rating of 2,000 W, and a lamp load of 36 W / cm at the time of rating is used. The irradiator includes a condensing type and a parallel light type. Among them, the condensing type is preferable because the irradiation width can be reduced.

  The stock solution channel material used in the present invention is a sheet-like thin porous material. Specifically, a plastic net having a three-dimensional cross structure is effective as a material having a small fluid flow resistance and a small thickness. As the permeate flow path material, a sheet-like thin porous material is used, but a material that can withstand an external pressure in the thickness direction is preferable. Specifically, a knitted fabric such as polyester tricot processed with resin is used.

  The water collection tube is provided for the purpose of collecting the permeated liquid that has permeated through the reverse osmosis membrane, and has a hollow shape and a large number of holes that are connected to the hollow portion on the surface of the tube. The material is made of a hard material such as PVC or ABS. Various materials such as plastic and metal such as stainless steel are used. The number of central tubes is basically one.

  The adhesive preferably has a viscosity in the range of 40 PS to 150 PS, and more preferably 50 PS to 120 PS. If the adhesive viscosity is too high, the reverse osmosis membrane and the permeate flow will be reduced when the laminated structure in which the reverse osmosis membrane unit and the permeate flow path material are alternately stacked is wrapped around the water collection pipe. It becomes difficult for the road material to slip on the bonding surface, and as a result, wrinkles are easily generated and the performance of the reverse osmosis membrane element is easily impaired. On the other hand, if the adhesive viscosity is too low, the adhesive will flow out of the predetermined adhesive surface part between the reverse osmosis membrane and the permeate flow path material to contaminate the device, and will adhere to unnecessary parts and reverse. While impairing the performance of the osmotic membrane element, the work efficiency of the spilled adhesive is remarkably lowered.

  The amount of the adhesive applied is preferably such that an application width of 5 mm to 80 mm can be secured after the reverse osmosis membrane unit is wound around the water collection pipe, for example, a range of 8 g to 30 g per side is preferable. If the coating amount is too large, the coating width becomes too wide and the permeation effective membrane area becomes narrow, and if it is too small, it causes a leak.

  In the present invention, the adhesive is preferably a urethane-based adhesive. In order to make the viscosity in the range of 40 PS to 150 PS, the isocyanate as the main agent and the polyol as the curing agent are used in the ratio of isocyanate: polyol = 1: 1 to 1: 5. What mixed in the ratio is preferable. The viscosity of the adhesive is measured in advance with a B-type viscometer (JIS K 6833) by measuring the viscosity of the main agent, the curing agent alone, and a mixture that defines the blending ratio.

It is a manufacturing flow figure which illustrates the process of laminating | stacking a reverse osmosis membrane unit and a permeate flow path material by this invention method. It is a schematic structure side view which shows the step before the thing laminated | stacked on the process of FIG. 1 is wound around a water collection pipe. It is a schematic side view which shows a winding process. It is a partially cutaway perspective view showing an example of a spiral type liquid separation element manufactured by the method of the present invention. It is the top view (A) and side view (B) which show an example of the apparatus in the case of drying one side part of a reverse osmosis membrane with a halogen heater.

Explanation of symbols

1. 2. Reverse osmosis membrane roll Working table 6. Cutter 8. Sheet-fed reverse osmosis membrane 9. Single-wafer stock solution flow path material10. Stock solution flow path material roll 11. Cutter 14. Reverse osmosis membrane unit 19. Permeate flow path material roll 20. Sheet-like permeate channel material 21. Cutter 27. Adhesive application gun 28. Adhesive application part 29. Laminated structure 34. Water collecting pipe 43. Drive roll 44. Nip roll 50. Irradiator 51. Halogen heater 52. Sheet-like reverse osmosis membrane 53. Underlay

Claims (8)

A spiral liquid separation element is manufactured by winding a permeate channel material, a reverse osmosis membrane, a stock solution channel material, and a reverse osmosis membrane sequentially around a hollow central tube having a hole on the surface. In the method, when the adhesive is applied to adhere the reverse osmosis membrane, the permeate channel material and the three sides of the reverse osmosis membrane, the adhesive applied portion of the reverse osmosis membrane in a wet state is dried before applying the adhesive. Then, a method of manufacturing a spiral liquid separation element, wherein an adhesive is applied and adhered. The method of drying the adhesive-applied portion of the reverse osmosis membrane is any one or a combination of drying by contacting a heated member, drying by blowing warm air, and drying by applying light. The method for manufacturing a spiral liquid separation element according to claim 1, wherein: 3. The method for producing a spiral liquid separation element according to claim 2, wherein the drying by applying light is drying by irradiation with light from a halogen heater. The adhesive is a urethane-based adhesive, wherein the main component isocyanate and the curing agent polyol are mixed in a weight ratio of isocyanate: polyol = 1: 1 to 1: 5. The manufacturing method of the spiral type liquid separation element in any one of Claims 1-3. The method for producing a spiral-type liquid separation element according to any one of claims 1 to 4, wherein the moisture content of the adhesive-applied portion of the reverse osmosis membrane is dried so as to be 10% or less when the adhesive is applied. . The reverse osmosis membrane is a reverse osmosis membrane having a laminated structure including a base material layer and a reverse osmosis functional thin film layer, wherein drying of the adhesive application portion is performed from the surface on the base material layer side. The manufacturing method of the spiral type liquid separation element in any one of 1-5. The method for producing a spiral liquid separation element according to claim 1, wherein the adhesive has a viscosity of 40 PS to 150 PS. The method for producing a spiral liquid separation element according to any one of claims 1 to 7, wherein the adhesive width of the adhesive-applied portion of the reverse osmosis membrane is in the range of 5 mm to 80 mm.

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