JPS61205796A - Total heat exchanging element - Google Patents

Abstract

PURPOSE:To improve moisture permeability and prevent elution of moisture absorbent upon high humidity or dewing by a method wherein a processing layer, containing porous base material, soluble high polymer, high moisture absorbing high polymer and the moisture absorbent as essential ingradients, is provided. CONSTITUTION:Employed high moisture absorbing high polymer is consisting of hydrolyzate of starch-acrylonitrile and grafting starch series isobutylene-maleic anhydride added with crosslinking agent. Soluble high polymer is commonly consisting of polyvinyl alcohol while moisture absorbent is commonly consisting of halogenated lithium. In case the element is consisting of soluble high polymer, powder high moisture absorbing high polymer and moisture absorbent, the powder high moisture absorbing high polymer is preferable to be 5-20% with respect to the soluble high polymer, the moisture absorbent is preferable to be 5-50% with respect to the soluble high polymer and 5-1,000% with respect to the high moisture absorbing high polymer. On the other hand, in case the soluble high polymer and the crosslinking agent are blended as the potential substance of the high moisture absorbing high polymer, the moisture absorbent is mixed by 5-1,000% with respect to the composition of soluble high polymer and crosslinking agent.

Description

[Detailed Description of the Invention] A. Purpose of the Invention Industrial Application Field The present invention relates to a total heat exchanger.Recently, heat exchangers have come to be used as ventilation devices for houses and buildings.
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 this total heat exchange element.

2. Description of the Related Art Conventional total heat exchange elements include, for example, the Hikosho 52-15
(As disclosed in Japanese Patent No. 171, a technique of treating a breathable porous body with a water-soluble polymer and lithium halide (hygroscopic agent) is known as a basic technique.

Further, Japanese Patent Application Laid-Open No. 59-tn7197 discloses a material to which a super absorbent resin is added.

Furthermore, JP-A-57-2 (17F+28) discloses a three-layer structure in which a porous member is coated with an aqueous solution of a hydrophilic polymer and a moisture absorbent, and another porous member is laminated thereon. ing.

However, Japanese Patent Application Laid-open No. Sho F16-89NF1 proposes an absorbent-containing paper impregnated with a water-absorbing agent.

Problems to be Solved by the Invention The conventional total heat exchange elements as described above are still unsatisfactory in terms of performance, and further improvements are desired. First of all, the above-mentioned special public service 1507-1507
The material disclosed in Publication No. 1 has a major drawback in that the moisture absorbent is eluted during high humidity or dew condensation, and the performance deteriorates over time, making it difficult to contain a large amount of moisture absorbent.

In addition, the super absorbent resin used in JP-A-59-1 (1719'7) has a low hygroscopicity compared to the moisture absorbent, and the total heat exchange efficiency is low. be.

Next, the method disclosed in JP-A-57-2117528 forms a moisture absorbing layer on the inside, so although it is effective in preventing elution of the moisture absorbent, it is not perfect, and the manufacturing process is complicated, and extra sheets are required. This has the problem of being disadvantageous in terms of cost due to the necessity of Furthermore, JP-A-56-
Since the product disclosed in the A9NN publication uses an adsorbent such as silica gel or activated carbon to adsorb moisture, it has the disadvantage that this effect is large on the static 1L type permeable type, especially in the case of the static 1L type transmission type.

The present invention was made with the aim of solving these drawbacks of the conventional technology.It is possible to improve moisture permeability by containing a large amount of moisture absorbing agent, and the moisture absorbing agent dissolves even in times of high humidity or dew condensation. The purpose of this project is to develop a total heat exchange element that does not cause heat loss.

Structure of the Invention The structure of the present invention is a total heat exchange element characterized in that a porous base material is provided with a treatment layer containing a water-soluble polymer, a super absorbent polymer, and a moisture absorbent as essential components. The gist of this paper is as follows.

Measures to solve the problem We considered adding an additive that does not reduce the hygroscopicity of the hygroscopic agent and also prevents the hygroscopic agent from eluting in times of high humidity or dew condensation. They have found that polymers with high molecular weight are very suitable.

When coating the Tsuma Q1 porous substrate with a water-soluble polymer and a moisture absorbent, we learned that if a highly water-absorbing polymer is blended into the solution, a very excellent effect can be obtained.

In other words, in order to achieve the object of the present invention, the treatment layer provided on the porous base material contains three essential components: a water-soluble polymer, a moisture absorbent, and a superabsorbent polymer. This makes it extremely effective.

The superabsorbent polymer in the present invention refers to a polymer compound that has an extremely high water absorption ability, and has the ability to absorb and retain water several hundred to 1,000 times its own weight, such as starch-acrylonitrile. Hydrolysates, polyacrylates, vinyl acetate-acrylic systems, vinyl alcohol-acrylic acid systems, other acrylic systems, isobutylene-manoic anhydride systems, grafted starch threads, etc. are available in powder form. The most well-known sweet liquid type is one made by adding a crosslinking agent to 1d inbutylene to maleic anhydride.

The superabsorbent polymer used in the present invention may change into a superabsorbent polymer during the treatment process (i.e., it may be a water-soluble polymer at the time of coating the porous substrate). It is also possible to use a material that reacts with a pre-mixed crosslinking agent during the drying process to produce a superabsorbent polymer.

In this case, the water-soluble polymer that is converted into a superabsorbent polymer may be of the same type as the water-soluble polymer that is combined with 8 as an essential component, or may be of a different type. Of course.

A similar example of the former is one that utilizes the fact that polyvinyl alcohol reacts with a cyclic acid anhydride such as maleic anhydride or phthalic anhydride to transform into a modified polyvinyl alcohol that has high water absorption performance. . A porous base material is prepared by adding a cyclic acid anhydride that reacts with polyvinyl alcohol by blending an excess amount of polyvinyl alcohol into the Tsumashikoat liquid, and adding a moisture absorbent to this. When the coating layer is coated and then subjected to dry heat treatment, the modified polyvinyl alcohol is generated, and the coated layer contains polyvinyl alcohol, highly water-absorbent modified polyvinyl alcohol, and a moisture absorbent. Examples of different types include water-soluble polymers in which hydrophilic groups such as carboxylic acids, carboxylates, and amides are introduced by applying an alkaline substance to Beo7fin-maleic anhydride copolymer, and polyvalent epoxy as a crosslinking agent. One example is to combine them. Examples of the α-olefin include unsaturated hydrocarbons having carbon atoms of 12 or less, such as ethylene, propylene, isobutylene, butene, and butadiene, and suitable alkaline substances include sodium hydroxide, ammonia, and methylamine. be. Further, as the polyhydric epoxy as a crosslinking agent, glycerin, glycidyl ether, C poly)ethylene glycol diglycidyl ether, glycerin triglycidyl ether, etc. are preferably used.

In the present invention, the superabsorbent polymer as an essential component may be incorporated by itself as described above, but
If a material that becomes a super absorbent polymer is added during the above-mentioned processing steps, the product will be superior in terms of processing. The reason is,
For example, if powdered superabsorbent polymer is added at the beginning, it will absorb water from the treated aqueous solution and swell, making coating difficult. be.

Therefore, before treatment or during coating, it is a water-soluble polymer, but through heat treatment such as the drying process, it changes from water-soluble to highly water-absorbent, and when it dries to almost no water content (it becomes a highly water-absorbent polymer). Things become the most convenient.

In the Examples described later, the method of converting the aforementioned different types of water-soluble polymers into superabsorbent polymers during the treatment process using a crosslinking agent is shown as an optimal example.

The water-soluble polymer as an essential component used in the present invention is most commonly polyvinyl alcohol, but other synthetic, semi-synthetic, and natural polymers such as methylated cellulose, sodium polyacrylate, polyacrylamide, starch, and Various water-soluble polymers can be used.

The moisture absorbent used in the present invention is most commonly a lithium halide such as lithium chloride, but calcium chloride, potassium acetate, guanidine hydrochloride, glycerin, triethylene glycol, etc. can also be used. Those used as dehumidifiers can be suitably used.

Next, the blending ratio of each essential component in the present invention will be explained.

1. In the case of a composition consisting of a water-soluble polymer, a powdered superabsorbent polymer, and a moisture absorbent, the powdered superabsorbent polymer absorbs water during processing, so it is often not mixed from the standpoint of efficiency. 〈〈The powdered superabsorbent polymer is preferably 5 to 20 parts per 100 parts of the water-soluble polymer, and the moisture absorbent at this time is 5 to 50 parts per 100 parts of the water-soluble polymer. 5 to 1000 parts per 100 parts of super absorbent polymer
It is desirable that the

On the other hand, when a water-soluble polymer and a crosslinking agent are combined as potential substances for a superabsorbent polymer, the moisture absorbing agent should be added in an amount of 5 to 1000 parts per 100 parts of the water-soluble polymer + crosslinking agent mixture.
There is no particular restriction on the blending ratio of the water-soluble polymer as an essential component and the above-mentioned latent substance in terms of the process. However, when coating with particular emphasis on gas barrier properties, use a water-soluble polymer with good film-forming properties such as polyvinyl alcohol or carboxymethyl cellulose in combination or combination to the extent that gas barrier properties and liquid retention properties are not impaired. It is desirable to determine the blending ratio.

Function In the present invention, the superabsorbent polymer exhibits the ability to absorb and retain moisture absorbed by the moisture absorbent, and its water retention capacity holds the moisture absorbent and water and prevents elution of the moisture absorbent. It exerts the effect of producing T, b Super absorbent polymer itself has a small ability to absorb water vapor from the air, but when a moisture absorbent absorbs water vapor from the air and converts it into liquid moisture, the super absorbent polymer absorbs this moisture. It immediately absorbs and retains water, and the two exert a synergistic effect, absorbing moisture from the humid air through the linked action of moisture absorption - moisture conversion → water absorption, and transferring it to the other low humidity air through the porous base material. It moves it to. Moreover, this super absorbent polymer retains the moisture absorbent along with the water due to its swelling action, so even if there is a lot of moisture at the edge of the basket, the moisture absorbent hardly ever elutes and falls off.

The water-soluble polymer as an essential component has the effect of forming the entire layer into a film shape, and forms the base of this treated layer, and is necessary to obtain a film layer with moisture permeability. There is no need to say that it is an ingredient.

Example: Polyvinyl alcohol with a degree of saponification of 99 degrees or less (denoted by PVA) was used as a water-soluble polymer that was an essential component,
A copolymer of isobutylene-maleic anhydride as a water-soluble polymer that produces a super absorbent polymer (hereinafter referred to as A)
Glycerin diglycidyl ether (hereinafter referred to as B) was used as the crosslinking agent for A. In addition, the above PVA, A,
B, lithium chloride in three ways shown in Table 1 INα1 to N1
Coating liquids were prepared with the mixing ratio of 5), and each was coated on a mixed paper made of pulp and glass fiber as a porous base material so that the amount of PVA attached was 5 g/d.

A pipe-type total heat exchanger was manufactured using each sheet thus obtained. In other words, from each sheet, a large number of pipes with an inner diameter of 6 meters and a length of 1 meter were made, 50 pipes were lined up horizontally at 5-way intervals, mouthpieces were attached to both ends, and these pipes were further stacked in 10 layers at 5-shoulder intervals for a total of 50 pipes. The total heat exchanger consisted of 500 pipes.

Two types of experiments were conducted using each of these total heat exchangers as described below.

Experiment: An air flow with RH 65% B 2°C was passed through the pipe, and an air flow with RH 4 (1% 25°C) was passed around the outer circumference of the pipe in opposition to the air flow, and the total heat exchange efficiency was measured.

Experiment 2: After experiment 1, RH90% as humid air
The total heat exchange element was subjected to severe humid treatment by passing airflow at B2°C both inside and outside the pipe for 100 hours. Then, the total heat exchange efficiency was measured under the same conditions as in Experiment 1.

These results are summarized in Table 1.

Table 1 According to this table, the experiment in which A and B, which produce superabsorbent polymers, are not blended is more effective than experiment 1.≠i
I understand.

In comparison, the difference between Experiment 1 and Experiment 2 for N[L2 and 3 was very small, and it was determined that the performance had hardly deteriorated even after long-term harsh treatment with humid air. It is recognized that this is a total heat exchange element that does not elute and does not change over time.

The crushed Nα3 contains twice as much moisture absorbent as the Nα2, and as a result, the total heat exchange efficiency is improved, resulting in very excellent results. This shows that the blending of super absorbent polymers makes it possible to increase the condensation rate of the moisture absorbent and greatly contributes to improving the performance of the total heat exchange element.

C. The effect layer of the invention is provided, and the process is particularly excellent when this super absorbent polymer is generated during the treatment process.

In the total heat exchange element of the present invention, even when the hygroscopic agent absorbs a large amount of water, such as during high humidity or dew condensation, the super absorbent polymer retains the hygroscopic agent along with this large amount of water, preventing its elution. However, it also eliminates the major drawback of the conventional method, which is that the total heat exchange efficiency decreases over time without being sticky. Furthermore, since the liquid retention capacity of this super absorbent polymer is extremely large, the blending ratio of moisture absorbing agent can be made much higher than that of conventional total heat exchange elements, and therefore the total heat exchange performance itself can also be improved. It has very good effects, such as being able to significantly improve the situation.

Claims (1)

[Scope of Claims] 1. A total heat exchange element comprising a porous base material and a treatment layer containing a water-soluble polymer, a highly water-absorbing polymer, and a moisture absorbent as essential components. 2. The total heat exchange element according to claim 1, wherein the superabsorbent polymer is produced during a treatment step by blending a water-soluble polymer and a crosslinking agent.