JPH0131295Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a moisture-sensitive filter that utilizes the phenomenon that a water-absorbing resin expands in volume when it absorbs moisture.

That is, the present invention relates to a filter in which a particulate or fibrous water-absorbing resin is sandwiched between mesh-like materials that have a mesh opening diameter that prevents the resin from flowing out and that allows liquid to pass through. Regarding filters that have the characteristics of absorbing and retaining water when water is mixed into a liquid that is not mixed with water, and clogging and blocking the flow of liquid when excessive water enters. .

In recent years, cross-linked polyethylene oxide, cross-linked polyvinyl alcohol, hydrolysates of starch-polyacrylonitrile graft polymers, partially cross-linked starch-poly(meth)acrylic acid copolymers, etc., have been made water-insoluble and highly absorbent. A substance has been proposed that absorbs water and swells when it comes into contact with water, retaining water hundreds to thousand times its own weight, and once absorbed, it does not release even if a small amount of pressure is applied. Water-absorbing resins have been developed.

These water-absorbent resins with high water-absorbing capacity can be used in sanitary products, disposable diapers, disposable wipes, paper towels, medical gauze, etc.
It is also used in a wide range of applications, including preventing dew condensation in interior building materials such as wall and ceiling materials, and retaining water in agricultural soil retention sheets.

Water-absorbing resins have the property of expanding in volume in proportion to the amount of water they absorb, but liquids other than water, such as hydrophobic organic solvents, absorb almost no water and therefore hardly change in volume. have characteristics.

The present invention utilizes the selective absorbing property of the water-absorbing resin, which absorbs water only when it is present and expands in volume.

That is, the present invention uses a plurality of mesh-like materials such as nonwoven fabrics that have an opening diameter large enough to prevent the water-absorbing resin from flowing out in the form of particles or fibers, and that are permeable to liquid. This is an idea for a liquid filter prepared by preparing a number of filters and filling the spaces between the mesh-like materials with water-absorbing resin (in other words, the water-absorbing resin is sandwiched between the mesh-like materials in a sandwich-like manner).

By placing the filter of the present invention in a path where oil, gasoline, etc., and organic solvents such as toluene, benzene, etc., which are normally set not to contain water, flow, failures etc. may occur in this path. If water gets mixed in, the water-absorbing resin in the filter absorbs and retains the water if it is a small amount, and only organic solvents other than water pass through the path after the filter, preventing water from entering.

Furthermore, if a large amount of water gets into this route,
The water-absorbent resin, which acts as a filter material, absorbs water and expands, reducing its pores and eliminating the flow path for the liquid, eventually blocking the flow of the organic solvent itself. However, it is possible to prevent moisture from flowing into the path after the filter.

Next, an embodiment of the moisture sensitive filter of the present invention will be explained with reference to the drawings.

FIG. 1 is a perspective view showing the entire moisture-sensitive filter, and FIG. 2 is a cross-sectional view of the moisture-sensitive filter taken horizontally in the direction of liquid flow. Cylinder 1
is for filling the water-absorbent resin 2 inside, and both sides are covered with a mesh material 3 to prevent it from flowing out, and the mesh material 3 is attached to the filling cylinder 1 of the main body by screws or other means using a fixing frame 4. It has a basic structure that is tightened.

The water-absorbing resin 2 used in the present invention includes a starch-sodium acrylate graft polymer, a hydrolyzate of a starch-crylonitrile graft polymer, and a partially crosslinked starch-poly(meth)acrylic acid copolymer. , partially cross-linked starch-polymethyl methacrylate hydrolyzate, starch-graft polymers such as salts of the above substances, and methyl methacrylate-vinyl acetate copolymer hydrolyzate. Examples include those based on crosslinked synthetic resins, but basically any material that is made of a water-soluble polymer that has been crosslinked at a low density and made insoluble in water is acceptable, and is not particularly limited.

The shape of the water-absorbing resin 2 may be particulate, fibrous, etc., but before absorbing water, it has a certain amount of voids, cannot block the flow of liquid, and after absorbing water, the voids are closed.
Any filling state may be used as long as it blocks the flow of liquid.

The mesh material 3 used in the present invention must have an opening diameter large enough to prevent the water-absorbent resin 2 from flowing out, and must be made of a material that allows liquid to pass through and is not attacked by the liquid used. In addition to nonwoven fabrics and woven fabrics, metals, glass fibers, synthetic resin nets, porous inorganic materials, etc. may be used.

The materials used for the filling cylinder 1 and the fixing frame 4 of the moisture sensitive filter body of the present invention must also not be attacked by the liquid used, and specifically metals, synthetic resins, ceramics, etc. can be used.

<Example 1> In the basic structure of the moisture sensitive filter of the present invention shown in the drawings, the filling cylinder and fixing frame were made of stainless steel with a maximum outer diameter of 5 cm and a height of 20 cm, and 250 mesh was used as the mesh material. The water-absorbing resin used was cross-linked acrylic water-absorbing resin powder (product name: Aqua Keep, manufactured by Steel Chemical Co., Ltd.).
10SH" particle size 32 to 200 mesh) was filled to obtain a moisture sensitive filter.

This moisture-sensitive filter was inserted into a glass tube, and the space between the filter and the glass tube was sealed with an epoxy adhesive. A glass tube containing a moisture-sensitive filter was placed vertically on the ground, and toluene mixed with 5% water by weight was poured into the opening at the top of the tube.
Toluene mixed with 1.3% water is obtained, and when this toluene is poured from the top of the glass tube again, the concentration is 0.6%.
% water was reduced. Furthermore, when this toluene was poured into the top of the glass tube, the water content decreased to 0.1%.

Therefore, from this result, it was confirmed that by preparing several moisture-sensitive filters and arranging them in series in multiple stages with respect to the flow, it is possible to almost completely remove moisture.

<Example 2> When only toluene was poured from the top into a glass tube equipped with the moisture sensitive filter shown in Example 1, a flow rate of 3.2 per minute was obtained from the bottom of the glass tube. Next, when toluene mixed with 5% water by weight was flowed through this glass tube for 3 minutes, the flow rate was 0.8 per minute, 0.2 per minute after 6 minutes, and completely stopped after 9 minutes. This can be said to be an effect of the water-absorbing resin in the moisture-sensitive filter absorbing water, expanding its volume, and blocking the flow path. Due to this phenomenon, it was possible to appropriately determine when to replace the moisture sensitive filter of the present invention with a new one.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the moisture sensitive filter of the present invention, and FIG. 2 is a sectional view of the main part of the embodiment shown in FIG. 1 taken at the center. 1...Filling tube, 2...Water absorbent resin, 3...Mesh material, 4...Fixed frame.

Claims (1)

[Scope of utility model registration request] A particulate or fibrous water-insoluble water-absorbing resin that expands in volume when it absorbs water is placed between the mesh materials to the extent that the water-absorbing resin will clog the filter when it absorbs a large amount of water. A moisture sensitive filter characterized by being filled.