JPH01299624A - Hygroscopic fiber - Google Patents

Abstract

PURPOSE:To obtain a moisture absorbing agent having high moisture absorbing capacity, high moisture absorbing velocity, easy handleability, and satisfactory shape retaining property after absorbing moisture by allowing fibers which are swelled by water as hygroscopic fiber to contain a moisture absorbing agent. CONSTITUTION:Any material having >=3cc/g, pref. >=5cc/g moisture absorbing factor may be useful so far as it is fibrous. Water swellable fibers such as those obtd. by modifying acrylic fiber, cellulose fiber, etc., to have water absorbing property, are used. A water-soluble moisture absorbing agent such as LiCl, CaCl2, is incorporated into said fibers. The hygroscopic fiber obtd. by this method has high moisture absorbing capacity and high moisture absorbing velocity. The fibers are handleable easily since the moisture absorbing agent is contained in the inside of water swellable fibers, generating no oozing of liquid generated after moisture absorption. The fiber is suitable for use at any kinds of place.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to hygroscopic fibers that remove moisture in space.

(Prior Art) Hygroscopic agents have conventionally been used as a means for removing moisture in space.

Shape retention even after moisture absorption p1 Reusable hygroscopic agents include silica gel, synthetic zeolite, sodium sulfate, activated alumina, and activator, but these hygroscopic agents have a small amount of moisture absorption, a slow moisture absorption rate, It has drawbacks such as requiring high temperatures for drying after absorbing moisture.

In addition, hygroscopic agents such as lithium chloride, calcium chloride, magnesium chloride, and phosphorus pentoxide absorb a large amount of moisture and also have a fast rate of moisture absorption, but these hygroscopic agents are deliquescent, and absorb moisture and liquefy and contaminate others. It has drawbacks such as difficulty in handling, difficulty in molding, and difficulty in recycling.

In order to solve this drawback, methods have been proposed in JP-A-52-17042 and JP-A-63-81522, which use a mixture of a water-absorbing resin and a deliquescent salt.

However, when using the moisture absorbent in the form of a sheet, nonwoven fabric, etc. by the above method, it is necessary to spray the moisture absorbent onto the sheet, nonwoven fabric, etc., and use means such as sandwiching or wrapping the moisture absorbent. There are problems such as easily falling off, insufficient moisture absorption ability, and requiring complicated steps to process into the above-mentioned form.

(Problems to be Solved by the Invention) The objects of the present invention are to absorb a large amount of moisture, have a fast moisture absorption rate, be easy to handle, be easily processed into various shapes, and have good shape retention after moisture absorption. The object of the present invention is to provide a hygroscopic fiber which has excellent properties and is also easily recyclable.

The present invention will be explained in detail below.

The water-swellable fibers related to the present invention have a water absorption capacity of 8 C.
e / 1 or more, preferably 5 cc / 1 or more, and can be used as long as it has a fiber shape, for example, acrylonitrile (hereinafter referred to as AN) , polyacrylate-
Heat-treated polyhydric alcohol copolymer, starch-acrylic alcohol or its salt copolymer, starch-AN
Saponified N-graft polymer, vinyl acetate-acrylic/L'
Fibers made of saponified acid ester copolymers, saponified vinyl acetate-unsaturated dicarboxylic acid copolymers, etc.; Acrylic fibers, cellulose fibers, polyvinyl alcohol fibers, etc. treated with water absorption modification treatment (hydrogel formation); Fibers Examples include those whose surface is coated with a hydrophilic polymer. Among them, Hydroge/L/ (water-absorbing and water-insoluble polymer)
Composite water-absorbing fibers, such as LANSEAL (registered version a of Nippon Exlan Kogyo Co., Ltd.), which is formed from an outer layer and an inner layer of AN-based polymer, have excellent water absorption ability and maintain practical levels of physical properties such as strength and elongation. Therefore, it is desirable that fiber molded articles such as sheets and nonwoven fabrics can be easily produced.

Next, the moisture absorbent used in the present invention may be any water-soluble moisture absorbent, and examples thereof include lithium chloride, calcium chloride, magnesium chloride, sodium VTFI, lithium bromide, phosphorus pentoxide, etc. Among these
Although a combination of salts or more salts may be used, monovalent salts are preferred because they have a high permeability into the hydrogel and, as a result, a large amount of the moisture absorbent can be contained in the hydrogel.

The content of such a moisture absorbing agent is preferably 1 to 40% based on the dry weight of the water-swellable fibers; if it is below the lower limit of this range, sufficient moisture absorption cannot be obtained, and if it exceeds the upper limit, it may cause damage to the fiber surface. Practical because the moisture absorbent is exposed and falls off or peels off.
It's not economical.

Next, the means for incorporating the moisture absorbent into the water-swellable A&fiber is not particularly limited as long as moisture absorbent fibers satisfying a predetermined moisture absorbent content can be obtained, but for example, the following means are preferably employed. be able to.

Water swelling in an aqueous solution of moisture absorbent ll11! i: soaking the fibers;
The water-swellable fibers are allowed to absorb the moisture absorbent aqueous solution and then dried.

Here, the concentration of the moisture absorbent is preferably 1 to 80% by weight,
More preferably, it is 1 to 2096. If the f! km properties, and it is not possible to increase the moisture absorbent content.

In addition, the forms of water-swollen 11il fibers include ultrashort fibers,
It may be in the form of either short fibers or long fibers, or may be processed into threads, woven fabrics, sheets, knitted fabrics, etc. and then treated with a moisture absorbent. Furthermore, other fibers such as natural, recycled, and synthetic fibers may be used. There is no problem in using them together.

The immersion temperature and time can be appropriately selected depending on the desired moisture absorbent content, but a temperature of 100c or less and a time of 10 seconds to 80 minutes are preferably used.

Next, it is preferable to completely remove the aqueous solution adhering to the cloth surface after liquid absorption by centrifugal dehydration or the like, since the moisture absorbent will not fall off or peel off from the fibers after drying.

Next, to dry the fibers, it is preferable to use a temperature of 80C to 200C; temperatures below 80C take a long time to dry, and temperatures above 2000C cause deterioration of the fibers.

The drying time is not particularly limited, as long as the m-fibers can be dried.

The above-mentioned drying conditions are also suitably used when regenerating fibers after moisture absorption.

(Effect of the invention) Hygroscopicity of the invention 1! The fiber absorbs a large amount of moisture, has a fast moisture absorption rate, and has a moisture absorbing agent inside the water-swellable fiber, making it easy to handle. Can be used.

In addition, it can be easily processed into various shapes, has excellent shape retention after moisture absorption, and since the moisture absorbent does not fall off, the moisture absorption ability of recycled bonds does not decrease, and food products such as confectionery and seaweed that dislike moisture □ 4; Storage area for daily necessities such as medicine closet and shoe rack;
A noteworthy effect of the present invention is that it has provided a hygroscopic fiber that can be suitably used for preventing dew condensation in houses.

(Examples) In order to facilitate understanding of the present invention, Examples are shown below, but the scope of the present invention is not limited in any way by the description of these Examples.

In addition, the percentages described in the examples are, unless otherwise specified,
! Based on ll1 weight standard.

In addition, the water absorption capacity and moisture absorption rate described in the following examples were measured and calculated by the following method.

■ Water absorption capacity (Ce/II) Immerse a 0.1F sample fiber in pure water and keep it at 25C for 24 hours.
After a period of time, the fibers were wrapped in a nylon filter cloth (200 mesh) and water between the fibers was removed using a centrifugal dehydrator (80 G x 80 minutes, where G is gravitational acceleration). The weight of the sample thus prepared is measured (wlg). Next, the sample is dried in an 80c vacuum dryer until it becomes the opposite weight, and the weight is measured (
wzg). From the above measurement results, it was calculated using the following formula. Therefore, the water absorption capacity is a numerical value that indicates how many times the weight of the fiber can absorb and retain water. Moisture absorption rate (%2) Sample fiber 5.Oy was dried with hot air *ai at 120C.

Dry for 5 hours and measure the weight C"113f) 6 Next,
The sample is placed in a predetermined constant temperature bath at a temperature of 20°C for 8M.

cw4y absorbs moisture in this way and measures the weight of the nine samples.
). From the above measurement results, it was calculated using the following formula.

Denier X5LM (water absorption rate 150cc/non-51,
After immersing in 500 cc of 6% lithium chloride aqueous solution at 20C for 80 minutes, centrifugal dehydration was performed at 800GX for 5 minutes, and then 120e in a hot air dryer.

After drying for 5 hours, a hygroscopic fiber 1 was obtained.

Next, hygroscopic fibers 2.8 and 4 were obtained in the same manner as above except that sodium sulfate, magnesium chloride, and calciramura chloride were used as the lithium chloride base.

Table 1 shows the measurement results of the moisture absorption rate of each hygroscopic fiber at relative humidity of 82%, 65% and 95%.
Hygroscopic '111 fibers 5.6 and 7 were obtained in the same manner as in Example 1 except that the fibers were reduced to 0%. The results are shown in Table 2.

Table 2 From Tables 1 and 2 above, it can be seen that hygroscopic fibers having a desired moisture absorption rate can be obtained depending on the type and content of the hygroscopic agent.

Further, no liquid seepage was observed from the hygroscopic delicate material after such moisture absorption.

Example 8! l! 1 g of the hygroscopic fiber l used in Example 1 was dried in a hot air dryer.
oc, after 6 hours of drying, again at 82% relative humidity, 66
When moisture was absorbed under % and 95%, each moisture absorption rate was 1
5.8%, 52.1%, and 195.6%, which shows that it is reproducible.

Claims (1)

[Claims] A hygroscopic fiber made of water-swellable fiber containing a hygroscopic agent.