JPS6028660B2 - Moisture-permeable gas shield - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a permeable gas shield used, for example, in a total heat exchanger of an air conditioning device, and in particular to an improvement in gas shielding rate.

In recent years, air conditioning equipment such as heating or cooling has developed and spread, and as the living areas using these equipment have expanded,
The characteristics of moisture permeable gas shields for air conditioning equipment are now required to have low air permeability and high moisture permeability.

Due to the way in which the total heat exchanger for air conditioning equipment is used, the air taken into the room from the outdoors does not mix with the air discharged from the room to the outdoors. Water vapor is also required to be transferred between the intake air and exhaust air to exchange heat). Therefore, in order to meet such demands, the present inventors first prepared an aqueous solution of a water-soluble polymer substance to which lithium halide (hygroscopic agent) was added, such as paper, cloth, nonwoven fabric, asbestos paper, etc.
We have invented a gas shield with improved green permeability, which has low air permeability and high moisture permeability, by impregnating or coating a porous member such as a thin ceramic plate.

(Hakama Sekisho 49-45882) The air permeability coefficient (quantitative value of breathability) and moisture permeability coefficient (quantitative value of moisture permeability) of this transparent woven gas shield are determined by the content of the lithium halide and water-soluble polymer substance. Depending on the rate, the air permeability coefficient mainly decreases with the increase of the content of water-lacquered polymeric substances, and the moisture permeability coefficient mainly increases with the increase of the content of lithium halide. however,
The air permeability coefficient and the moisture permeability coefficient of the gas shield do not change independently, but when the content of the hydrophobic polymer substance is increased in order to reduce the air permeability, the moisture permeability coefficient also decreases.
Ha to improve moisture permeability. It is not enough to increase the content of lithium genide; it is also necessary to simultaneously decrease the content of water-soluble polymeric substances. In this way, with regard to the content of water-soluble polymer substances, the decrease in the air permeability coefficient and the increase in the green permeability coefficient of gas shielding materials are in a contradictory relationship, and therefore, conventional moisture permeable gas shielding materials provide high moisture permeability and low velocity air permeability. There was a limit to what I could do.

However, in order to further improve the performance of total heat exchangers for air conditioning equipment, a gas shield with improved permeability that provides high moisture permeability and low air permeability has become required, and the present inventors As a result of extensive research, we found that by slightly impregnating a non-hydrophobic porous material with a weakly hydrophobic material, water solubility cannot easily penetrate into the interior, and then a solution of a polymeric substance containing a moisture absorbent is added. When we created a gas shield with a structure in which a dense hygroscopic thin layer was formed on the surface layer of a porous member by impregnating or coating it with It was discovered that a transparent green gas shielding material having excellent selective gas permselectivity could be obtained, and the present invention was completed.

That is, the gist of the present invention is to form a layer of a polymeric substance containing a moisture absorbent on a weakly hydrophobic porous member through which at least water molecules flow.

The weakly hydrophobic porous member is preferably a non-hydrophobic porous member made of a weakly hydrophobic material, such as a natural resin such as rosin or casein, which is generally used as a sizing agent.
Alternatively, solutions using synthetic resins such as melamine resin, vinyl resin, polyester resin, and polyamide resin (
Preferably, those that have been subjected to a weak hydrophobic treatment by immersion in an aqueous solution or the like are used.

In this weakly hydrophobic treatment, it is preferable that the non-hydrophobic porous portion is impregnated with about 1 to 2% by weight of the weakly hydrophobic material. If the amount of impregnation is less than 1%, the weak hydrophobic effect will not appear, and if it is more than 20%, the voids in the porous portion will become smaller, impairing moisture permeability and increasing hydrophobicity, which is not preferable. Further, as the non-hydrophobic porous member, for example, Japanese paper, filter paper, Western paper, asbestos paper, glass fiber paper, textile fabric, nonwoven fabric, or a thin plate of porous ceramics can be used. Further, as the moisture absorbent, halides, oxides, acid salts, hydroxides, etc., which are generally used as drying agents, as well as hygroscopic substances, polyhydric alcohols, etc. can be used.

Lithium halide is preferably used. Further, as the polymer substance, a general water-soluble synthetic resin, a natural substance, or a mixture thereof is usually used, such as polyvinyl alcohol resin, polyvinyl methyl ether resin,
Polyacrylic acid resin, polymethacrylic acid resin, methyl cellulose, etc. are used.

Furthermore, when forming a dense hygroscopic thin layer of the polymeric material containing the moisture absorbent on the weakly hydrophobic porous member, the content may be 20 to 5% by weight with respect to the porous member. It is preferable to do so.

If the content is less than 2% by weight, the air permeability will be high, and if the content is more than 5% by weight, the moisture permeability will be poor, so both are not preferred. Such a thin layer may include, for example, the moisture absorbents 1 to 5
It is suitably formed by a method such as preparing an aqueous solution of 5 to 2% by weight of the polymeric substance and soaking or coating the porous member with this aqueous solution.
Note that, for example, a flame retardant may be added as necessary. In the thus obtained permeable gas shield, a layer of a polymeric substance containing a moisture absorbent is formed as a fine hygroscopic thin layer on the surface or surface layer of a weakly hydrophobic porous member as a base. ,
For example, gases such as air and carbon dioxide are blocked by this delicate thin layer and can hardly pass through, but water vapor is adsorbed on the surface of the hygroscopic thin layer and condenses to form liquid water. It can be permeated by moving the capillary tubes present in the thin layer by capillary force, reaching the back surface of the porous member, and vaporizing again from this back surface.

Note that water vapor can permeate in any direction depending on the concentration gradient of water vapor.

Furthermore, the liquid water filling the capillary tube can sufficiently prevent gas from permeating through the capillary tube.

This will provide a high degree of gas selective permselectivity. The moisture-permeable gas shield obtained in this way is used as it is or in a layered manner, for example, in a total heat exchanger for air conditioning equipment. This is extremely advantageous in terms of hygiene management, as it exchanges heat without mixing with the air discharged outdoors, and the moisture in the air is transferred from the intake air to the discharged air, reducing changes in indoor humidity and temperature. .

Furthermore, since this transparent green gas shielding material has permeation selectivity for gas molecules, it is widely used in various other fields. The present invention will be explained below with reference to Examples.

Example 1 Industrial furnace paper was soaked in a 16% rosin aqueous solution and subjected to a weak hydrophobic treatment.

After drying (impregnation rate 12%) lithium chloride content 2.3% (weight %, same hereinafter) and polyvinyl alcohol content 12%
A fine, hygroscopic thin layer was formed on the surface layer of the industrial furnace paper. The content of lithium chloride and polyvinyl alcohol was 26%. The cross section of the moisture-permeable gas shield obtained in this way has the structure shown in Figure 1, and the lithium chloride and polyvinyl alcohol observed under a microscope are relatively dense and few It formed a porous membrane with many capillaries.
In the figure, 1 is furnace paper, and 2 is a hygroscopic thin layer formed on the surface layer of this furnace paper 1. The characteristics of this moisture-permeable gas shield and the characteristics when it was used as a partition of a total heat exchanger were as shown in the table below.

Example 2 Japanese paper was impregnated with a 12% melamine resin solution (impregnation rate 16).
%) Weak hydrophobic treatment was performed.

An aqueous solution containing 3.8% lithium bromide and 8% polyvinyl alcohol was applied to this weakly hydrophobic Japanese paper to form a hygroscopic thin layer. The content of the hygroscopic polymer substance is 21
%Met. The moisture-permeable gas shield thus obtained had the cross-sectional structure shown in FIG. In the figure, 1 is Japanese paper, and 2 is a hygroscopic thin layer formed on the surface of the Japanese paper 1. The properties of this moisture permeable gas shield and the properties when used as a partition member of a total heat exchanger are as shown in the table below.

Example 3 A porous ceramic plate was impregnated with a 13% aqueous rosin solution (impregnation rate 10%) to perform a weak hydrophobic treatment.

This weakly hydrophobic ceramic plate contains 4% lithium chloride.
A hygroscopic thin layer was formed on the surface by immersing the polyacrylic acid resin in a 15% aqueous solution. The properties of the moisture-permeable gas shield thus obtained and the properties when used as a partition member of a total heat exchanger are as shown in the table below.

Reference Example A moisture-permeable gas shielding material was obtained in the same manner as in Example 1 without performing the weak hydrophobic treatment using industrial furnace paper.

In addition, since the weak hydrophobization treatment was omitted, the moisture absorbent and the polymer substance were mixed into the interior of the industrial furnace paper, resulting in a content of about 35%. The properties of the moisture-permeable gas shield thus obtained and the properties when used as a partition member of a total heat exchanger are as shown in the table below.

Table '1} shown in the above table was measured on the plate-shaped sample obtained as described above, and '2} was measured using this to fabricate a simulated total heat exchanger. This is what was measured.

Note that the specific gas leakage rate was measured using carbon dioxide gas. As is clear from this table, the improvement in gas leakage rate is particularly remarkable.

As explained above, this invention achieves good moisture permeability by using a weakly hydrophobic porous material and forming a layer of a hygroscopic polymer material thereon to form a moisture permeable gas shield. It has the effect of reducing air permeability while maintaining

[Brief explanation of the drawing]

Both FIGS. 1 and 2 are sectional views showing one embodiment of the present invention. In the figure, 1 is a weakly hydrophobic porous member, and 2 is a thin layer of a hygroscopic polymeric material. Note that the same symbols in each figure indicate corresponding parts. 1st
Figure 2

Claims (1)

[Claims] 1. A moisture-permeable gas in which a layer of a polymer material containing a moisture absorbent is formed on a weakly hydrophobic porous member through which at least water molecules flow, and the layer blocks gas. Coverage. 2. The moisture-permeable gas shield according to claim 1, wherein the weakly hydrophobic porous member is a non-hydrophobic porous member impregnated with a weakly hydrophobic material. 3. The moisture-permeable gas shield according to claim 2, wherein Japanese paper is used as the non-hydrophobic porous member. 4. The moisture-permeable gas shield according to claim 2, wherein filter paper is used as the non-hydrophobic porous member.
5. The moisture permeable gas shield according to claim 2, wherein ceramic is used as the non-hydrophobic porous member. 6. The moisture permeable gas shield according to claim 2, wherein a sizing agent is used as the weakly hydrophobic material. 7. The moisture-permeable gas shield according to claim 6, wherein glue is used as the sizing agent. 8. The moisture-permeable gas shield according to claim 2, wherein a synthetic resin is used as the weakly hydrophobic material. 9. The moisture-permeable gas shield according to claim 8, wherein melamine resin is used as the synthetic resin. 10. The moisture-permeable gas shield according to any one of claims 1 to 9, wherein lithium chloride is used as the moisture absorbent. 11. The moisture-permeable gas shield according to any one of claims 1 to 10, wherein polyvinyl alcohol is used as the polymeric substance.