JP2002186837A - Fluid separation element and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid separation element and a manufacturing method therefore aiming at an adhesive used for the fluid separation element and capable of reducing an amount of elution substance from the adhesive. SOLUTION: The fluid separation element is formed using at least a separation membrane and an adhesive. In the fluid separation element and the manufacturing method therefor, it is characterized in that a consumption of potassium permanganate of the adhesive curing substance in use against a substance to be oxidized is 2 ppm/g or less.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid separation element and a method for manufacturing the same, and more particularly, to the amount of eluted substances from an adhesive in an element in which the separation membranes are bonded to each other or the separation membrane is bonded to a counterpart member using an adhesive. The present invention relates to a fluid separation element and a method for manufacturing the fluid separation element, which can reduce the pressure.

[0002]

2. Description of the Related Art Separation membranes, for example, reverse osmosis membranes, are bonded to each other in a predetermined bag shape using an adhesive, or a separation membrane unit formed in a single separation membrane or in a bag shape is collected. 2. Description of the Related Art The structure of a fluid separation element that is adhered to a mating member such as a water pipe is known. For example, separation membranes composed of reverse osmosis membranes are adhered in a bag shape so as to sandwich a raw liquid flow path material therebetween to form a separation membrane unit, and the separation membrane unit and the permeate flow path material are alternately stacked and collected. A spiral fluid separation element wound around a water tube is known.

[0003] When processing using such a fluid separation element, particularly when a processing solution containing extremely few impurities is required, for example, when performing processing for producing ultrapure water, the processing liquid is transferred from the fluid separation element to the processing water. It is necessary to keep the amount of eluted material extremely low. In order to reduce the amount of eluted substances from the separation membrane itself and other constituent members of the fluid separation element, various materials have been proposed for such constituent materials, but little attention has been paid to adhesives.

[0004]

As mentioned above, when assembling a fluid separation element, an adhesive is usually used for joining various parts, especially for joining separation membranes. When used for the purpose, it is used in the form of a mixture with a dedicated cured product. The cured adhesive comes into contact with the undiluted solution or the permeated processing liquid more or less, but if the amount of eluted from this adhesive is large, the amount of eluted substance in the processing liquid will not matter even if a high-performance separation membrane is used. It is difficult to keep the low level. In particular, when producing ultrapure water, it is required to reduce the amount of eluted substances in the treated water, especially the amount of TOC (total organic carbon) eluted.

Accordingly, an object of the present invention is to provide a fluid separation element which can pay attention to an adhesive used for a fluid separation element and reduce the amount of eluate from the adhesive, and a method of manufacturing the same. .

[0006]

In order to solve the above-mentioned problems, a fluid separation element of the present invention is a fluid separation element formed using at least a separation membrane and an adhesive. The cured product is characterized in that the consumption of potassium permanganate with respect to the oxidizable substance is 2 ppm / g or less.

In this fluid separating element, the adhesive is
It is preferable that the resin be cured at a curing temperature of 30 ° C. or more and 50 ° C. or less. The higher the temperature of the adhesive, the more the reaction proceeds. Therefore, by adopting such curing temperature conditions, a desired cured state can be obtained quickly. Preferably, the cured adhesive has been cured to a reaction rate of 95% or more before washing with warm water. It is desirable to carry out the reaction as much as possible before washing with hot water.

[0008] In particular, a reverse osmosis membrane can be used as the separation membrane.

[0009] The method for manufacturing a fluid separation element according to the present invention comprises:
When the separation membrane is bonded with an adhesive, the method comprises using a cured adhesive having a consumption of potassium permanganate to the oxidizable substance of 2 ppm / g or less.

In this method, it is preferable to cure the adhesive at a curing temperature of 30 ° C. or more and 50 ° C. or less, and it is preferable to cure the adhesive to a reaction rate of 95% or more before washing with warm water. A reverse osmosis membrane can be used as the separation membrane.

In the fluid separation element and the method of manufacturing the same according to the present invention, in order to reduce the amount of eluted substances from the adhesive, a specific adhesive cured product is used, particularly focusing on the adhesive cured product. I do. That is, the amount of eluted oxidizable substance, particularly the amount of TOC eluted, can be substantially determined by the consumption of potassium permanganate, so that the consumption of potassium permanganate relative to the oxidizable substance is not more than a specific value, In other words, by using an adhesive cured product of 2 ppm / g or less, the amount of eluted material from the cured adhesive can be suppressed to an extremely low level.

[0012] By optimizing the curing conditions of the adhesive using the specific cured adhesive, the amount of eluted material from the cured adhesive can be further reduced.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail. In the fluid separation element of the present invention, an adhesive is used to bond the separation membranes or the separation membrane to a partner member (for example, a water collecting pipe),
A cured adhesive is used to cure the adhesive. As the adhesive, for example, an adhesive composed of a polyurethane resin composition or the like is used. For example, an adhesive containing a main agent composed of a polyisocyanate component and a curing agent composed of a polyol component as a cured adhesive is used. As the cured adhesive, a specific cured adhesive having a potassium permanganate consumption of 2 ppm / g or less relative to the oxidizable substance is used.

As for the cured adhesive itself, various performances can be adjusted by communicating required specifications to an adhesive maker. In the present invention, potassium permanganate consumption for an oxidizable substance is particularly 2 ppm. / G or less of the specific cured adhesive is used.

The consumption amount of potassium permanganate can be used as a representative index indicating the amount of the oxidizable substance eluted from the adhesive, and in particular, the TOC elution amount can be quantified.

The method for measuring potassium permanganate consumption is as follows:
The method for measuring the consumption of potassium permanganate described in the “Instruments and Containers and Packaging” in the Ministry of Health and Welfare's “Standards for Foods and Additives (Extracts)” can be applied.

If the consumption of potassium permanganate with respect to the oxidizable substance of the cured adhesive used exceeds 2 ppm / g, it is difficult to achieve the extremely low amount of eluate in the treatment fluid, which is the target of the present invention, In particular, it is difficult to keep the TOC elution amount low under extremely severe water quality conditions such as ultrapure water generation.

The amount of eluted material from the cured adhesive is as follows:
Since it changes depending on the curing conditions of the adhesive, a lower amount of eluted material can be achieved by optimizing the curing conditions.

The curing temperature of the adhesive is preferably in the range of 30 ° C. to 50 ° C., since the higher the temperature, the more the curing proceeds. That is, a curing condition of 30 ° C. or higher, which is higher than room temperature, is selected. If the temperature is too high, the adhesive itself may be deteriorated or the separation membrane may be adversely affected.

At the stage when the adhesive is almost cured,
Wash off deposits, precipitates, impurities, etc. by washing with warm water,
After a while, it is provided for processing. By the time of performing the hot water washing, the curing reaction of the adhesive is substantially completed, and it is preferable that the hot water adversely affects the curing reaction or that the hot water and the adhesive do not cause an undesirable reaction. . In other words, the higher the reaction rate until the washing with warm water, the lower the amount of eluate can be reduced,
It is desirable to advance the reaction as much as possible before washing with hot water, and it is desirable that the adhesive has undergone a curing reaction to a reaction rate of 95% or more before washing with warm water.

In the treatment using the fluid separation element according to the present invention, when the treatment is performed after washing with hot water,
Within a very short time after the start of the treatment, a processing fluid having an extremely low eluted substance amount, particularly a TOC elution amount, can be obtained. In addition, when stored for a long time before the actual treatment after washing with hot water, the amount of TOC eluted generally increases, but the amount of eluted material in the fluid separation element according to the present invention is extremely low in the manufacturing stage. Therefore, for example, even if processing is started after storage for about one month, within a very short time after the processing is started,
A processing fluid with an extremely low eluted amount, especially a TOC eluted amount is obtained.

[0022]

EXAMPLE 1 An operating pressure of 1.5 MPa and a membrane flux of 1.0 m using a fluid separation membrane module in which one spiral type fluid separation element using the cured adhesive of the present invention is accommodated in a pressure vessel.
^The TOC elution amount was measured under the conditions of ³ / m ² · day, a recovery rate of 50%, and a temperature of 25 ° C. The hot water washing conditions are as follows: temperature 60 ° C., pressurizing pressure 0.4 MPa, membrane flux 0.4 m
^The test was performed at ³ / m ² / day for 20 hours. The fluid separation element has a diameter of 200 mm, a length of 1 m, and a packed membrane area of 39 m ^2.
In this case, the separation membranes are bonded to each other with an adhesive so as to form a bag. The adhesive was cured at 40 ° C. for 30 hours, and had a reaction rate of 95% before washing with warm water. The consumption amount of potassium permanganate of the cured adhesive was 2 ppm / g.

The results are shown in Table 1. Table 1 shows that the TOC concentration of the permeated water 3 hours after the start of the treatment was very low immediately after the washing, and further decreased 10 hours after the start of the treatment. Also,
After washing with hot water, even after storage for one month, the increase in TOC concentration is about 2 ppb compared to the above value (TOC concentration 3 hours after the start of treatment), and the time required for startup is extremely short. Has become.

Comparative Example 1 The same adhesive (main agent) as in Example 1 was cured at a temperature of 25 ° C. for 20 hours, with a conversion of 85% and a consumption of potassium permanganate of the cured adhesive of 5 ppm / g. A fluid separation element similar to that of Example 1 was used except that was used. The TOC elution amount was measured using the same fluid separation element membrane module as in Example 1.

The results are shown in Table 1. Immediately after washing and after storage for one month, the TOC concentration was higher than that in Example 1. In addition, the value immediately after the cleaning was at the same level as the value without the hot water cleaning.

[0026]

[Table 1]

[0027]

As described above, according to the fluid separation element and the method of manufacturing the same of the present invention, the use of an adhesive cured product having a potassium permanganate consumption of a specific value or less allows the fluid separation element to be removed from the fluid separation element. Can be treated with an extremely low amount of eluted material, and extremely excellent treatment performance can be exhibited in the production of ultrapure water and the like.

Claims (10)

[Claims] 1. A fluid separation element formed by using at least a separation membrane and an adhesive, wherein a consumption amount of potassium permanganate with respect to an oxidizable substance of a used cured adhesive is 2 ppm / g or less. A fluid separation element, comprising: 2. The fluid separation element according to claim 1, wherein the adhesive is cured at a curing temperature of 30 ° C. or more and 50 ° C. or less. 3. The cured adhesive has been cured to a reaction rate of 95% or more before washing with hot water.
Or 2 fluid separation elements. 4. The separation membrane according to claim 1, wherein the separation membrane is a reverse osmosis membrane.
The fluid separation element according to any one of the above. 5. The fluid separation element according to claim 1, which is for generating ultrapure water. 6. The fluid separation element according to claim 1, wherein the adhesive is used to bond the separation membrane to the oxidizable substance, and the consumption of potassium permanganate to the oxidizable substance is 2 ppm / g or less. Production method. 7. The method for manufacturing a fluid separation element according to claim 6, wherein the adhesive is cured at a curing temperature of 30 ° C. to 50 ° C. 8. The method for producing a fluid separation element according to claim 6, wherein a curing reaction of the adhesive is performed to a reaction rate of 95% or more before washing with hot water. 9. The separation membrane according to claim 6, wherein the separation membrane is a reverse osmosis membrane.
The method for producing a fluid separation element according to any one of the above. 10. A method for producing ultrapure water, comprising using the fluid separation element according to any one of claims 1 to 5 to reduce the amount of eluate from an adhesive during processing.