KR20150076665A - Composite fiber aggregate for total heat exchange element, Preparation method thereof and total heat exchange element comprising the same - Google Patents

Abstract

The present invention relates to a composite fiber assembly for heat exchange elements and a manufacturing method thereof and, more specifically, a composite fiber assembly, which is made by introducing hydrophilic fibers to melt-blowing fibers with bulky property, thereby implementing water vapor transmission and air permeability at the same time, a manufacturing method thereof and a heat exchange element including the same.

Description

TECHNICAL FIELD [0001] The present invention relates to a composite fiber aggregate for an electric heating exchange element, a method for manufacturing the composite fiber aggregate, and an entire heat exchange element including the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite fiber aggregate for an electrothermal converting element having a bulky structure and a manufacturing method thereof, and further relates to an electrothermal switching element including the same.

Recently, it has been pointed out that various syndromes are emerging due to volatile organic compounds emitted from building materials, furniture, and daily necessities in the room.

To solve these problems, it has become mandatory to install ventilation equipment in buildings by the recently revised Building Standard Act, and ventilation is added to domestic air conditioners, and ventilation of buildings is being promoted.

As the airtightness of the buildings increases, and the ventilation becomes difficult due to the change of lifestyle due to the diffusion of the air-conditioning and heating, the volatile organic compounds can easily stay indoors. In order to solve this problem, An entire heat exchanger that is less likely to be emitted and suppresses energy consumption has been attracting attention. That is, there is a growing need to develop a heat exchanger capable of preventing waste of energy due to ventilation in a ventilation system for exchanging fresh outside air with contaminated air in the room.

The total enthalpy heat exchanger has a structure in which spacers are disposed between a liner stacked in a vertical direction with a certain space therebetween, and each liner. The liner functions as a heat exchange medium between the air flowing in the upper part and the lower part, and the spacer has a corrugated shape to form an air flow path for air flow. The air flow path has a structure in which the air flow paths intersect with each other. One of the air flow paths is a flow path through which room air flows to the outside, and the other is a flow path through which outdoor air flows into the inside. Accordingly, the indoor air and the outdoor air pass through the liner while exchanging heat with each other while passing through the respective air passages, and the latent heat or the sensible heat of the indoor air to be discharged is absorbed by the outdoor air sucked.

Currently, paper materials are mainly used as total heat exchange materials. Paper materials can cause dew condensation in the process of exchanging heat, and there is a possibility that corruption may occur because the mold due to the generation of moisture may be inhabited. Also, it has a disadvantage in that it is difficult to apply to a total heat exchanger having a high flow rate of 8,000 CMH (Cubic Meter per Hour) or more because of low impact and tensile strength. It is urgently required to develop a new energy saving heat transfer material having improved durability capable of improving the disadvantages of such paper materials. In the prior art patent (Publication No. 10-2012-0029873, Publication No. 10-2005-0040068, etc.), there is mentioned a functional paper technology for an electric heat exchanger having improved the existing paper material. A technology for replacing existing paper heat exchanging materials with a meltblown nonwoven fabric made of a paper material has been researched and developed. In a prior patent (Publication No. 10-2013-0009081), a nonwoven fabric is impregnated with polyvinyl acetate, However, since there is a problem of low moisture permeability, it is not able to replace the conventional paper material.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a composite fiber aggregate in which hydrophilic monomers are introduced into meltblown fibers so as to replace an existing heat exchange element of a paper material, Method.

In order to solve the above-mentioned problems, the present invention relates to a composite fiber aggregate for an electric heating exchange element, comprising meltblown fiber; And polyvinyl acetate (PVA) staple fibers, synthetic fibers coated with a hydrophilic polymer, and natural fibers.

In one preferred embodiment of the present invention, the hydrophilic staple fiber has a degree of saponification of 85% to 98%, a fineness of 0.1 to 10 denier, and a fiber length of 22 mm to 64 mm.

In one preferred embodiment of the present invention, the meltblown fibers include alpha-olefins containing at least one selected from the group consisting of ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene; And low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene, polypropylene random copolymer, poly 1-butene, poly 4-methyl-1-pentene, ethylene propylene random copolymer, ethylene 1-butene random copolymer A polyolefin containing at least one selected from propylene 1-butene random copolymer; And an olefin compound containing at least one member selected from the group consisting of an olefin compound and an olefin compound.

Further, as a preferred embodiment of the present invention, the meltblown fibers may have an average diameter of 1 탆 to 10 탆.

In another preferred embodiment of the present invention, the composite fiber aggregate comprises meltblown fibers and hydrophilic staple fibers at a weight ratio of 4 to 9: 1 to 6.

In another preferred embodiment of the present invention, the various types of composite fiber aggregates described above may be nonwoven fabrics having a surface area of 40 to 100 g / m ² .

As another preferred embodiment of the present invention, the various types of composite fiber aggregates described above have a water vapor permeability of 6,000 to 9,000 g / m ² · 24 h measured at a surface density of 50 g / m ^{2 according to the} ISO 2528 test method .

In another preferred embodiment, the composite fiber aggregate of the various forms described above of the present invention, the surface density 50 g / m ² day time, ISO5636 / 5 the measured air permeability of 5,000 ~ 10,000 sec / 100㎖ on the basis of the test method . ≪ / RTI >

Another aspect of the present invention relates to a method of producing the composite fiber aggregate for various types of heat exchanging elements as described above, wherein an olefin resin containing at least one selected from alpha-olefin and polyolefin is heated at a hot air temperature of 250 < Characterized in that a composite fiber aggregate is produced by blowing hydrophilic staple fibers to a spinning meltblown stream when spinning the meltblown at 280 ° C to mix the spinning meltblown fibers with the hydrophilic staple fibers .

In one preferred embodiment of the present invention, the hydrophilic staple fibers may be characterized in that they have been subjected to an opening process and a carding process before blowing.

As a preferred embodiment of the present invention, in the production method of the present invention, the composite fiber aggregate is prepared by mixing the meltblown fibers and the hydrophilic staple fibers, , And then calendered at 100 ° C to 120 ° C.

Further, the present invention relates to an all-heat-exchanging element characterized by including the above-described various types of composite fiber aggregates, and further relates to an total enthalpy heat exchanger including the total heat-exchanging element.

Unlike the electrothermal exchange element in which a conventional hydrophilic polymer is coated or impregnated with a conventional hydrophilic polymer, the composite fiber aggregate for an electrothermal converting element of the present invention has excellent durability as well as excellent moisture permeability and excellent durability. It is expected that it will replace the total heat exchange element.

Fig. 1 is a schematic view of the composite fiber aggregate for electric heat exchanger prepared in Example 1. Fig.
Fig. 2 is a schematic view of a composite fiber aggregate for an electric heating exchange system according to the present invention, in which supporting layers are introduced on both sides.

Hereinafter, the present invention will be described in more detail.

When the olefin resin such as alpha-olefin or polypropylene is melt-blown at a hot air temperature of 250 ° C to 280 ° C, the composite fiber aggregate of the present invention blows hydrophilic staple fibers to the melt- the mixed fiber bundle comprising the meltblown fibers 12 and the hydrophilic short fibers 11 as shown in Fig. 1 can be produced by mixing the melt-blown fibers and the hydrophilic staple fibers by blowing them. At this time, if the hot air temperature is less than 250 ° C, the thickness of the polypropylene meltblown fibers becomes thick, so that it is difficult to ensure the desired degree of air permeability and moisture permeability. When the temperature exceeds 280 ° C, the polypropylene meltblown fibers are not stably focussed The hydrophilic fibers can not be mixed stably and the structure of the composite fiber aggregate may be poor. Therefore, it is preferable to perform the operation within the above temperature range.

In the present invention, the hydrophilic staple fibers serve to form a hydrophilic channel in the complex fiber aggregate. As the hydrophilic staple fibers, there are used polyvinyl acetate (PVA) staple fibers, synthetic fibers coated with a hydrophilic polymer, and natural fibers At least one selected from among PVA short fibers and synthetic fibers coated with a hydrophilic polymer may be used.

In the present invention, the hydrophilic staple fiber preferably has a fineness of 0.1 to 10 denier, preferably 3 to 7 denier, and when it is less than 0.1 denier, there may be a problem in opening the staple fiber, and when it exceeds 10 denier There is a problem of maintaining the moisture permeability and permeability performance of the target total heat exchanging element, and therefore, it is preferable to use the material within the above range. The hydrophilic staple fibers preferably have a fiber length of 22 to 64 mm, preferably 30 to 45 mm, more preferably 35 to 40 mm. If the fiber length is less than 22 mm, , It is difficult to maintain uniformity of fiber bundle because it is difficult to supply uniform quantities. When the fiber bundle exceeds 64 ㎜, the bundle of short fibers having a relatively thick thickness Because of the increase in the number of individuals, there may be a problem that the performance of the moisture permeability and the specularity is deteriorated.

The hydrophilic polyvinyl alcohol staple fiber preferably has a degree of saponification of 85 to 98%, preferably 88 to 95%. When the degree of saponification is less than 85%, the stiffness of the staple fiber is low , And if it exceeds 98%, the hydrophilicity may be lowered. Therefore, it is preferable to use hydrophilic staple fibers having a degree of saponification within the above range.

The meltblown fiber 12, which is one of the components of the composite fiber aggregate of the present invention, is not particularly limited as long as it is melt-blown and can form meltblown fibers. However, ethylene, propylene, 1 One or more alpha-olefins selected from butene, 1-hexene, 4-methyl-1-pentene and 1-octene; Or low density polyethylene, linear low density polyethylene (LLDPE), high density polyethylene (HDPE), polypropylene, polypropylene random copolymer, poly 1-butene, poly 4-methyl-1-pentene, ethylene propylene random copolymer, At least one polyolefin selected from random copolymers and propylene 1-butene random copolymers; Polyester, polyamide (nylon-6, nylon-66, polymethoxyl adipamide and the like); Polyvinyl chloride; Polyimide; Ethylene-vinyl acetate copolymer; Ethylene vinyl acetate vinyl alcohol copolymer; Ethylene (meth) acrylic acid copolymers; Ethylene-acrylic acid ester-carbon monoxide copolymer, polycarbonate; And polystyrene; At least one selected from the above-mentioned alpha-olefins; And the polyolefin, and more preferably, the polyolefin is used.

The meltblown fiber 12 may have a diameter of 1 to 10 탆, preferably 1 to 5 탆. If the diameter of the meltblown fiber is less than 1 탆, the production cost is greatly increased due to a decrease in productivity. There may be a problem that the sound absorption performance is decreased due to the decrease of the compression recovery rate. When the diameter exceeds 10 탆, the structure of the composite fiber aggregate is not formed densely, which may result in a problem of durability deterioration have.

The composite fiber aggregate of the present invention preferably contains the meltblown fiber and the hydrophilic short fiber in a weight ratio of 4 to 9: 1 to 6, preferably 4 to 8: 2 to 6, When the amount of the meltblown fibers is less than 4 parts by weight, the hydrophilic staple fibers are increased and the pores of the composite fiber aggregate are increased. As a result, the air permeability is greatly decreased, If the amount of hydrophilic short fibers is less than 2 parts by weight in the ratio of 8: 2 by weight, hydrophilic channels may be less in the composite fiber aggregate, and the effect of improving the moisture permeability may be insufficient. Therefore, the composite fiber aggregate is preferably prepared so as to have a weight ratio within the above range.

As described above, in the composite fiber aggregate of the present invention, the meltblown fibers 12 composed of ultrafine fibers and the hydrophilic short fibers 11 are present together at a specific ratio, so that they can form a large surface area and an air layer, As well as,

The composite fiber aggregate of the present invention described above is a nonwoven fabric having a surface density of 40 to 100 g / m ² , preferably a surface density of 40 to 80 g / m ² , more preferably 40 to 70 g / m ² good. In this case, when the surface density is 40 g / m ² , sufficient mechanical properties such as strength and durability are not obtained, and there may be a problem in development of durability and moisture permeability. When the density exceeds 100 g / m ² , The resistance is increased, and as a result, there is a problem that the dumping performance is deteriorated. Therefore, it is preferable to have the surface density within the above range.

Such a composite fiber aggregate of the present invention, the surface density 50 g / m ² days time, as measured in accordance with ISO2528 test water vapor transmission rate is ^{6,000 ~ 9,000 g / m 2 ·} 24h, preferably 6,100 ~ 8,700 g / m ² · 24 h, and more preferably 6,200 to 8,600 g / m ² · 24.

When the area density of the composite fiber aggregate of the present invention is 50 g / m ² , the permeability is 5,000 to 10,000 sec / 100 ml, preferably 5,500 to 9,500 sec / 100 ml when measured according to the ISO 5636/5 test method , And more preferably 5,800 to 9,200 sec / 100 ml. If the air permeability is too low, the amount of air to be permeated becomes too large. If the permeability is high, the amount of air to be permeated becomes too small. As a result, the air stays for a proper time, It is good enough to exchange them.

As shown in FIG. 2, the composite fiber assembly 10 of the present invention can be applied to various known materials applied to the surface of the interior cover such as a nonwoven fabric, a woven fabric, a knitted fabric, a foam, Known materials such as paper, spunbond fabric, meltblown fabric, staple web and the like can be used alone, or two or more support layers 20 and 30 can be formed. The support layers 20 and 30 maintain the shape of the composite fiber aggregate and provide strength and prevent the hydrophilic staple fibers 11 from being detached as the seal passes to maintain the moisture permeability and permeability constantly. have.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples should not be construed as limiting the scope of the present invention, and should be construed to facilitate understanding of the present invention.

[ Example ]

Example  One

PVA fibers having a degree of saponification of 88 to 95%, a fineness of 7 da (de) and a fiber length of 38 mm were prepared. Next, the PVA staple fibers were subjected to opening and carding processes, and then blown into polypropylene melt blown yarns having an average diameter of 2.3 탆 through a blowing device to obtain polypropylene meltblown fibers The short fibers and the PVA short fibers were mixed. The meltblown spinning temperature and hot air temperature were set at 270 ° C. Then, the PVA fibers were mixed with each other in a vertically descending meltblown air stream so that the PVA staple fibers were 20% by weight and the polypropylene meltblown fibers were 80% by weight. The total area density was 50 g / m ² Were prepared. The resultant was passed through a hot chamber at 120 ° C at a speed of 5 m / min to heat-set, and then calendered at 110 ° C to produce a nonwoven fabric as shown in Fig.

Example  2 ~ Example  3

A composite fiber aggregate (total area density of 50 g / m ² ) in the form of a meltblown nonwoven fabric having a PVA staple fiber of 40 wt% and a polypropylene meltblown fiber of 60 wt% was prepared in the same manner as in Example 1 Example 2 was carried out.

Then, a composite fiber aggregate in the form of a meltblown nonwoven fabric having 60% by weight of PVA staple fibers and 40% by weight of polypropylene meltblown fibers was produced in the same manner as in Example 1, g / m < ² >) was performed

Example  4

Except that the PVA fibers having a degree of saponification of 88 to 95%, a fineness of 6 da (de) and a fiber length of 35 mm were 50% by weight and a polypropylene meltblown fiber was 50% by weight, (Total area density of 50 g / m < ² >) in the form of a non-woven fabric was prepared and Example 4 was carried out.

Example  5

Except that 40% by weight of PVA fibers having a degree of saponification of 88 to 95%, a fineness of 6 denier (de), a fiber length of 35 mm and a meltblown content of 60% by weight of polypropylene meltblown fibers were measured in the same manner as in Example 1, (Total area density of 70 g / m < ² >) in the form of a non-woven fabric was prepared.

Comparative Example  One

Polypropylene melt blown yarns having an average diameter of 2.3 占 퐉 were spun to prepare a fibrous aggregate having a total area density of 50 g / m < ^{2 &} gt ;. The meltblown spinning temperature and hot air temperature were set at 270 ° C.

Next, the fiber aggregate was immersed in a final processing agent using a 6% / L PVA aqueous solution and 6% lithium chloride (LiCl) relative to the PVA content to adjust the pickup ratio to 9% Lt; RTI ID = 0.0 > 130 C < / RTI > for 1 minute. Next, calendering was carried out at 110 DEG C and 55 kPa to prepare a polypropylene nonwoven fabric impregnated with a PVA aqueous solution.

Comparative Example  2

(Total area density of 50 g / m ² ) in the form of a meltblown nonwoven fabric having 10% by weight of PVA staple fibers and 90% by weight of polypropylene meltblown fibers was produced in the same manner as in Example 1 Comparative Example 2 was conducted.

Comparative Example  3

A composite fiber aggregate (total area density of 50 g / m ² ) in the form of a meltblown nonwoven fabric having 70% by weight of PVA staple fibers and 30% by weight of polypropylene meltblown fibers was prepared in the same manner as in Example 1, Comparative Example 3 was carried out.

Comparative Example  4

Except that PVA short fibers having a saponification degree of 88 to 95%, a fineness of 4 denier (de) and a fiber length of 75 mm were 40% by weight and polypropylene meltblown fibers were 60% by weight, (Total area density of 50 g / m < ² >) was prepared and Comparative Example 4 was carried out.

Comparative Example  5

Except that PVA short fibers having a degree of saponification of 88 to 95%, a fineness of 4 denier (de) and a fiber length of 75 mm were 40% by weight and polypropylene meltblown fibers were 60% by weight, (Total area density of 50 g / m < ² >) was prepared and Comparative Example 4 was carried out.

Experimental Example  One : Moisture permeability  And specularity measurement experiment

The moisture permeability and permeability of each of the meltblown nonwoven fabric composite fibers prepared in the above Examples and Comparative Examples were measured by the following methods, and the results are shown in Table 1 below.

(One) Moisture permeability  How to measure

The moisture vapor permeability (g / m ² · 24 h) per 24 hours was measured by measuring the weight of water vapor passing through the composite fiber assemblies of Examples and Comparative Examples at a relative humidity of 90% according to the ISO2528 test method.

(2) Method of measuring air permeability

The Gurley permeability (sec / 100 ml), which is the time taken for 100 ml of air to pass through the composite fiber assemblies of the Examples and Comparative Examples, was measured according to the ISO 5636/5 test method.

division Water vapor permeability (g / m ² 24h) Air permeability (sec / 100 ml) Example 1 6,548 8,560 Example 2 7,212 8,924 Example 3 8,121 7,841 Example 4 7,612 8,042 Example 5 7,414 8,412 Comparative Example 1 4,947 9,342 Comparative Example 2 5,741 9,241 Comparative Example 3 5,804 8,731 Comparative Example 4 5,915 8,241

As a result of the test results shown in Table 1, the composite fiber aggregates of Examples 1 to 5 exhibited excellent moisture permeability and permeability. However, in the case of Comparative Example 1 in which the PVA resin was impregnated in the nonwoven fabric, the coated PVA resin blocked the pores of the fiber aggregate, which increased the resistance and increased the time taken for the permeation, m ² · 24h. Further, in the case of Comparative Example 2, the moisture permeability was less than 6,000 g / m ² · 24h, which means that the hydrophilic channel was so small that the effect of improving the moisture permeability was insufficient.

In the case of Comparative Example 3 and Comparative Example 4 using hydrophilic staple fibers having a fiber length exceeding 64 mm, the fiber length of the staple fibers was too long to be uniformly mixed into the meltblown fiber aggregate, and the hydrophilic channels were relatively small This results in relatively poor water vapor permeability.

Through the above Examples and Experimental Examples, it was confirmed that the composite fiber aggregate of the present invention not only has excellent moisture permeability and permeability but also excellent physical properties such as strength and durability. This composite fiber aggregate of the present invention replaces the conventional paper heat exchanger as a material for solving the problem of dew condensation and durability which is a problem of a paper material used as a conventional total heat exchanger, It is expected to be able to provide.

10: composite fiber aggregate 11: PVA staple fiber
12: polypropylene meltblown short fibers 20, 30: support layer

Claims (12)

Meltblown fibers; And
Hydrophilic staple fibers containing at least one selected from polyvinyl acetate (PVA) staple fibers, synthetic fibers coated with a hydrophilic polymer, and natural fibers;
Wherein the composite fiber aggregate for an electric heating exchange element comprises:
The composite fiber aggregate for electric heating exchange elements according to claim 1, wherein the hydrophilic staple fiber has a degree of saponification of 85% to 98%, a fineness of 0.1 to 10 denier, and a fiber length of 22 mm to 64 mm.
The method of claim 1, wherein the meltblown fibers
Alpha-olefins containing at least one selected from ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and 1-octene; And
But are not limited to, low density polyethylene (LDPE), high density polyethylene (HDPE), polypropylene, polypropylene random copolymer, poly 1-butene, poly 4-methyl-1-pentene, ethylene propylene random copolymer, ethylene 1-butene random copolymer, A polyolefin containing at least one selected from a 1-butene random copolymer;
Wherein the olefin compound comprises at least one member selected from the group consisting of ethylene,
The composite fiber bundle for an electric heating exchange element according to claim 1, wherein the meltblown fibers have an average diameter of 1 占 퐉 to 10 占 퐉.
The composite fiber aggregate for an electric heating exchange element according to claim 1, wherein the composite fiber aggregate comprises meltblown fibers and hydrophilic staple fibers at a weight ratio of 4 to 9: 1 to 6.
The composite fiber aggregate according to any one of claims 1 to 5, wherein the composite fiber aggregate is a nonwoven fabric,
And a surface area of 40 to 100 g / m < ² >.
The composite fiber aggregate according to claim 6, wherein the composite fiber aggregate has a moisture permeability of 6,000 to 9,000 g / m ² · 24 h measured at a surface density of 50 g / m ² according to the ISO2528 test method, and is measured according to the ISO 5636 / And a time-permeability of 5,000 to 10,000 sec / 100 ml.
When the olefin resin containing at least one selected from the group consisting of alpha-olefins and polyolefins is melt-blown at a hot air temperature of 250 ° C to 280 ° C, the hydrophilic staple fibers are blown to the melt- ) To produce a composite fiber aggregate by mixing the melt-blown fibers and the hydrophilic short fibers to be radiated.
The method of claim 8, wherein the hydrophilic staple fibers are subjected to an opening process and a carding process before the blowing process.
The composite fiber aggregate according to claim 8, wherein the composite fiber aggregate is passed through a hot chamber at 110 to 130 占 폚 at a speed of 4 to 6 m / min to heat-fix the fiber aggregate, and then calendered at 100 to 120 占 폚. (EN) METHOD FOR PRODUCING COMPOSITE FIBER COLLECTION.
The total enthalpy heat exchanging element according to claim 6, comprising the composite fiber aggregate.
11. The total enthalpy heat exchanger according to claim 11, comprising the total heat-exchanging element.

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