JPS60259897A - Total heat exchange element - Google Patents

Abstract

PURPOSE:To improve the water resistant adhesion property and to make the moisture permeability and the gas barrier property excellent, by a method wherein cellulose ester and organic high molecular materials having large hydrophilic nature and elasticity and having capability to form films by oneself and compatibility, are mixed and compounded in a solvent, and is made into the moisture permeable film. CONSTITUTION:Cellulose ester and organic high molecular materials having the compatibility with cellulose ester, larger hydrophilic nature and elasticity than cellulose ester, and the film forming capability by oneself are mixed and compounded in a solvent, and is made into moisture permeable film by coating and drying. The brittleness of this elment is covered cellulose ester being elasticified by high molecular material, and moisture permeability and film forming property are improved by the hydrophilic nature of high molecular material, and is excellent for the gas barrier property and total heat exchange property is improved, and also water resistance adhesion property becomes good. It is desirable to treat moisture permeable films for porosity sheets.

Description

[Detailed description of the invention] B. Purpose of the invention Industrial applications The present invention relates to a total heat exchanger.

Recently, heat exchangers have been used as ventilation systems for houses and buildings, and in particular, total heat exchangers, which perform not only sensible heat exchange but also latent heat exchange at the same time, are becoming popular as extremely useful devices.

This total heat exchange is achieved by partitioning the two types of air streams to be heat exchanged by an element having thermal conductivity and moisture permeability. The present invention relates to a total heat exchange element.

Prior Art Conventional total heat exchange elements include, for example, the Japanese Patent Publication No. 50-68
82, in which a fibrous base material is impregnated with a hygroscopic organic polymer resin, JP-B No. 52-10214, in which a hydrophilic organic polymer film alone is used, JP-B No. 51-42884 Those using Japanese paper or asbestos paper or unglazed ceramics impregnated with high-boiling point polyhydric alcohol, etc., as in No. 1987, and those using polyhydric alcohol in a hollow membrane of regenerated cellulose as in JP-A-54-87955. As in JP-A-54-18657R1, a porous material is impregnated with a solution of a hydrophilic polymer containing an additive, and then the additive is removed to form pores and a hygroscopic substance is attached to the porous material. can be given.

Problems to be Solved by the Invention Among these conventional technologies, for example, those using hydrophilic polymers have a major drawback in that they have poor water-resistant adhesion, and the parts where elements are bonded together contain water and are easily peeled off. Products using this hydrophilic polymer have a problem in that their moisture permeability is significantly reduced at low humidity. Similarly, those using polyhydric alcohol also have the disadvantage of weak adhesiveness when moisture is absorbed.

In addition, none of these conventional technologies can be said to have satisfactory total heat exchange performance, and it is necessary to further improve the most important physical properties of this element, that is, gas barrier properties (air impermeability) and moisture permeability. considered desirable.

The present invention improves water-resistant adhesion and improves moisture permeability and gas barrier properties.
The object of the present invention is to provide a total heat exchange element that has excellent properties and can therefore improve total heat exchange performance.

Structure of the Invention The structure of the present invention consists of esterified cellulose, which has greater hydrophilicity and flexibility than the esterified cellulose, has film-forming ability by itself, and is compatible with the esterified cellulose. The gist of the present invention is a total heat exchange element characterized by having as an essential component a moisture-permeable film containing an organic polymer substance.

Measures to Solve the Problem First, we focused on the high moisture permeability of esterified cellulose, and researched using it alone and various plasticizers, but the combination of ordinary plasticizers resulted in a decrease in moisture permeability. Knowing that there is a drawback that the plasticizer gradually migrates and elutes, resulting in large changes over time, we further investigated the combination of various substances, and as shown in the patent application filed at the same time as the present invention. We succeeded in finding an organic substance that meets the specific conditions of maintaining the full moisture permeability of esterified cellulose, improving film-forming properties, and improving water-resistant adhesion. At the same time, organic polymers that do not act as plasticizers but can be blended with esterified cellulose as a suitable blend material to improve total heat exchangeability and water-resistant adhesion can also be used in addition to organic substances under these specific conditions. He succeeded in inscribing the material into ink.

This organic polymer substance is compatible with esterified cellulose, has greater hydrophilicity and flexibility than esterified cellulose, and has film-forming ability by itself.

In the present invention, esterified cellulose, for example cellulose acetate is the most common one, and examples of the organic polymer substances include low acetate cellulose acetate, low saponification degree polyvinyl alcohol, partially esterified polyacrylic acid. etc.

Low-acetyl cellulose acetate is more hydrophilic and flexible than cellulose acetate with a high degree of acetylation, which has a group of +7, has film-forming ability by itself, and is naturally compatible with cellulose acetate having a group of 1. It is.

Also, similar to the above, low saponification degree polyvinyl alcohol has much higher hydrophilicity and flexibility than cellulose acetate.
It also has compatibility with cellulose acetate.

Note that polyvinyl alcohol with a high degree of saponification has poor compatibility with cellulose acetate and cannot be used for the purpose of the present invention.

Similarly, partially esterified polyacrylic acid also has the above-mentioned physical properties necessary for the present invention, like the above two types of polymeric substances.

If the hydrophilicity of these polymeric substances is lower than that of esterified cellulose, the moisture permeability will decrease, and if the flexibility of these polymeric substances is lower than that of esterified cellulose, it will not be possible to compensate for the brittleness of esterified cellulose. Furthermore, if these polymeric substances do not have film-forming ability, if they are blended with esterified cellulose, this blend will also have low film-forming ability and poor gas barrier properties.

Note that these polymeric substances are not limited to those that require compatibility in order to be blended with esterified cellulose, and may be any other organic polymeric substance that satisfies the above conditions. Of course.

The device of the present invention is prepared by mixing and blending the above-mentioned organic polymeric substance and esterified cellulose in a suitable solvent, and coating and drying the mixture to form a moisture-permeable film. The device of the present invention may use this film alone, but in most cases, this film is formed by treating a porous sheet such as a base paper to form an integral film. It is used for

Note that the blending ratio of esterified cellulose and the organic polymer substance described above does not need to be particularly limited, but the former is usually 90 to 50%
It is preferable to mix 10 to 50 parts by weight of the latter to 0 parts by weight.

Function The device of the present invention has gas barrier properties because the esterified cellulose is softened by the polymer substance to cover its brittleness, and the hydrophilicity of the polymer substance improves moisture permeability and film forming properties. Therefore, the total heat exchangeability is improved, and the water-resistant adhesive property is also improved due to the polymeric material.

Example 1 A blend of 70 parts by weight of cellulose acetate with a degree of acetylation of 55 degrees and a degree of polymerization of 150 as a polymer material with a degree of acetylation of 45 degrees and a degree of polymerization of 1
The sample was coated with cellulose acetate of 305g7/d, air-dried, and then heat-treated at 80°C for 5 minutes to prepare a test piece.

Example 2 70 parts by weight of cellulose acetate, the same as in Example 1, and 30 parts by weight of polyvinyl alcohol with a degree of saponification of 40% as a blended polymer substance were coated on the base paper in the same amount as in Example 1. Comparative Example 1 Cellulose acetate with a degree of acetylation of 61 degrees and a degree of polymerization of 360 was used in place of the blended polymer material of Example 1, and methinone chloride was used as a solvent. The conditions were all the same as in Example 1, and the base paper was coated to the same amount and heat treated in the same manner to prepare a test piece.

Comparative Example 2 Polyethylene glycol was used as a hydrophilic plasticizer instead of the blended polymer of Example 1, and the other conditions were as in Example 1.
A test piece was obtained in the same manner.

Blank test] Only the base paper used in Example 1 was used as a test piece.

Blank test 2 The base paper used in Example 1 was coated with a solution of only the base cellulose acetate from Example 1 to a coating weight of 5 g solids/rpf, and was heat-treated in the same manner to obtain a test piece. .

For each of the above test specimens, a total heat exchanger was fabricated to exchange total heat through the bellows-type partition surface, and each
A two-way total heat exchange between outside air at 2°C and indoor air at RH 4nm and 25°C is performed to improve humidity exchange efficiency, latent heat exchange efficiency, carbon dioxide transfer rate (gas transferability), water resistance adhesion, and curl. When the phenomena were measured, the results shown in the following table were obtained.

(Margin below C) 0 In terms of water-resistant adhesion, the mark O indicates that the test piece was laminated with ethyl-vinyl acetate/I/resin and did not peel off after being immersed in water for 5 minutes. In addition, regarding the curl phenomenon, those with a large change over time are marked with an X, those with a slight change are marked with a Δ, and those with almost no change are marked with an ○.

From this table, it is recognized that Examples 1 and 2 have excellent latent heat exchange properties, low moisture permeability, good gas barrier properties, and high water-resistant adhesion. Since it is not possible to cover the blank test 1, it has the disadvantage that, like blank test 2, the curling phenomenon is significant. 1, Comparative Example 2 had poor gas barrier properties and water resistant adhesion, and Blank Test 1 had very low gas barrier properties.

Furthermore, Examples 1 and 2 overcome the drawback of cellulose acetate, which is brittleness, and improve film-forming properties.

C. Effects of the Invention As explained in detail above, the total heat exchange element of the present invention improves the moisture permeability of the esterified cellulose by adding a polymeric substance having high flexibility and hydrophilicity to the esterified cellulose. It overcomes the fragility, improves film-forming properties, and improves its gas barrier properties, making it extremely useful as a total heat exchange element. It has the excellent effect of not peeling off when it absorbs moisture.

B

Claims (1)

[Claims] 1. Esterified cellulose, which has greater hydrophilicity and flexibility than the esterified cellulose, has film-forming ability by itself, and is compatible with the esterified cellulose. 1. A total heat exchange element comprising, as an essential component, a moisture-permeable film containing an organic polymeric substance containing: 2. The total heat exchange element according to claim 1, wherein the porous sheet is treated with a moisture permeable film as an essential component.