JP2003236480A - Washing method for water absorbing article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a washing method for water absorbing articles which can prevent the water absorbing properties of the water absorbing articles including a synthetic fiber from being deteriorated after washing them repeatedly, keep the feeling good, and allows the reuse of the articles. <P>SOLUTION: This washing method comprises a process where, in washing of the water absorbing articles including the synthetic fiber, the articles are treated with an aqueous solution containing a hydrophilic polyester resin and/or a hydrophilic polyurethane resin and then heat treated at 140°C or lower. It is preferable that the washing is sterilizing washing where hot water treatment is performed in the presence of chlorine, and it is preferable that the synthetic fiber is a polyester fiber. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a washing method suitable for a water-absorbent article that is repeatedly reused. More specifically, the present invention relates to an optimal washing method for diapers used in hospitals and the like.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for diapers, sick clothes, etc. used in hospitals, bed sheets, pillow covers, yukatas, etc. used in hotels other than hospitals, and water absorbent articles used for them. The use of is also increasing rapidly. From the viewpoint of environmental problems, water-absorbent articles that can be reused by washing have been attracting attention rather than disposable water-absorbent articles. However, the conventional product made of 100% cotton has drawbacks that it consumes a large amount of energy when it is washed for reuse, especially when it is dried, and wrinkles easily occur. Therefore, in recent years, water-absorbent articles containing synthetic fibers, which dry quickly and are easy to handle, have been attracting attention. However, since these synthetic fibers are hydrophobic fibers, they have inferior water absorbency, and there is an essential problem that it is difficult to retain a large amount of water.

As a method for improving this drawback, a method of blending a hydrophilic substance at the spinning stage as a modification at the stage of the fiber raw yarn (Japanese Patent Laid-Open No. 50-711676),
A number of treatment methods have been proposed, such as a treatment method with an aqueous dispersion of a block copolymer containing polyalkylene glycol (Japanese Patent Publication No. 45-10794). But,
Although the water-absorbing performance of the water-absorbent article that has been subjected to these treatments is practical for initial performance and household laundry, it is sufficient for many unspecified people to reuse these water-absorbing articles. Therefore, there is a problem that the water absorbing performance cannot be maintained for the water absorbent article after such washing.

Incidentally, since such a water absorbent article is generally outsourced to a cleaning company, guidelines are provided for a washing method for sufficient washing and sterilization. For example, regarding the washing method for diapers, "Guideline of the Ministry of Health and Welfare for Rental Diapers" issued by Japan Diaper Business Promotion Association (November 2, 1993)
5 days) and the washing method is shown in detail. The guidelines define washing with hot water at 60 ° C. or 80 ° C. for 10 minutes or more, washing with a free chlorine concentration of 250 mg / liter or more, and the like. In addition, regarding bedding, the Ministry of Health and Welfare Health Policy Bureau Guidance Section Manager's notice “About outsourcing of hospitals, clinics, etc.” (May 1999)
In the 10th day of the month, No. 37), the washing conditions are almost the same as those of diapers.

[0005]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above-mentioned problems of the prior art and to prevent the water absorption performance from being deteriorated even when the water absorbent article containing synthetic fibers is repeatedly washed and to have a feeling. It is an object of the present invention to provide a good and reusable method for washing a water absorbent article.

[0006]

A method of washing a water-absorbent article according to the present invention is a method for washing a water-absorbent article containing synthetic fibers, in which the article is treated with an aqueous solution containing a hydrophilic polyester resin and / or a hydrophilic polyurethane resin, Next, the method is characterized by having a step of heat treatment at a temperature of 140 ° C. or lower. Furthermore, it is preferable that the washing is a sterilization washing in which hot water treatment is performed in the presence of chlorine, and the synthetic fiber is a polyester fiber.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method of washing a water absorbent article of the present invention relates to washing of a water absorbent article containing a synthetic fiber. An article to be absorbed, which is particularly suitable for the washing method of the present invention, is a sheet-like article, particularly preferably a cloth made of fibers. Here, the form of the fibers constituting the cloth may be either a long fiber filament processed yarn or a spun yarn in the case of a woven or knitted material, and may be a long fiber entangled body or a short fiber entangled body in the case of a non-woven fabric. Also,
It may be a cotton-like stuffed cotton or the like, or may be a laminate of woven or knitted fabric, non-woven fabric, stuffed cotton or the like. More specifically, it is a diaper, a hospital wardrobe or the like used in a hospital or the like, a bed sheet, a pillow cover, a yukata or the like which is also used in a hotel or the like other than the hospital,
In particular, the washing method of the present invention is effective for products such as cloth diapers that are washed a great number of times.

The synthetic fibers contained in the water-absorbent article which is the object of the present invention include any of polyester fibers, polyamides, acrylic fibers and the like, however, a synthetic fiber content is preferably high because it is a lightweight cloth. . A particularly preferred synthetic fiber is polyester fiber. The higher the content of polyester fibers, the better the dimensional stability during industrial washing, the easier the dehydration during washing, the shorter the drying time, and the less energy consumed in the washing process. Further, heat shrinkage in the drying process tends not to occur, wrinkles are less likely to occur after drying, and the ironing process can be omitted. Examples of the polyester fiber include polyethylene terephthalate fiber, polybutylene terephthalate fiber, polyethylene naphthalate fiber, and the like, and polyethylene terephthalate fiber is most suitable from the viewpoint of cost and performance balance. It may also contain other components such as a hydrophilic component and a pigment.

The content of synthetic fibers in the water absorbent article is 1
It is preferably 0% by weight or more, and more preferably 50% by weight or more. In particular, when the synthetic fiber is a polyester fiber and the water absorbent article is a 100% polyester fiber product, it can be recycled as a polymer raw material, which is preferable. As the remaining components other than synthetic fibers, natural fibers such as cotton, regenerated fibers such as rayon can be used, or materials other than fibers may be used.

The water absorbent article used in the present invention is preferably one in which the fiber surface is subjected to a hydrophilic treatment to further promote the water absorbing function. As the hydrophilic treatment, for example, fibers modified by blending polyethylene glycol with polyester may be used, or the polyester surface may be treated with alkali or other hydrophilic treatment to make the fiber surface hydrophilic. The water absorption may be improved by changing the ratio. The preferred initial water absorption rate is 10 seconds or less according to JIS L1018A method (dropping method),
Particularly preferred is a water-absorbing article for 1 second or less, and the washing method of the present invention is preferably applied to such a water-absorbing article.

The washing method of the present invention is a method of treating an absorbent article as described above with an aqueous solution containing a hydrophilic polyester resin and / or a hydrophilic polyurethane resin.

The hydrophilic polyester resin used in the present invention is a polyester resin containing a hydrophilic component such as polyethylene glycol. More specifically, for example, a polyester polyether block copolymer having terephthalic acid as an acid component, Isophthalic acid and an ester-forming derivative thereof, or / and a sulfonic acid metal group-containing dicarboxylic acid such as dimethyl 5-sodium sulfoisophthalate are contained in an amount of 0 to 40 mol% based on the total amount of the acidic component. Aliphatic glycols such as glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol, neopentyl glycol and the general formula [Chemical formula 1] (wherein R is hydrogen or an alkyl group, an aryl group, a cycloalkyl group, n It is a positive integer determined by the molecular weight.) A copolymer containing polyethylene glycol having a molecular weight of 600 to 4000, and / or an ester-forming derivative thereof in an amount of 20 to 80% by weight, preferably 40 to 80% by weight. To be Commercially available products of these hydrophilic polyester resins are SR-10 manufactured by Takamatsu Yushi Co., Ltd.
00, SR-1800, SR-6200, SR-500
0, Nicepol PR manufactured by Nika Kagaku Co., Ltd.

[0013]

[Chemical 1]

Further, in the washing method of the present invention, the hydrophilic polyurethane resin used simultaneously with or separately from the hydrophilic polyester resin is a polyurethane resin having a hydrophilic group such as a hydroxyl group, and more specifically,
For example, a liquid organopolysiloxane, a polyether polyol containing a polyoxypropylene group, and a polyurethane compound obtained by reacting a specific tertiary amino compound containing at least two hydroxyl groups in one molecule with a diisocyanate compound are available. Can be mentioned. Commercially available products of these polyurethane-based resins include Evaphanol N and Evaphanol N-20 manufactured by Nichika Chemical Co., Ltd., MTB-516 and TS-1437 manufactured by Takamatsu Yushi Co., Ltd., and the like.

The method for washing a water-absorbent article of the present invention comprises a step of treating with an aqueous solution containing the above-mentioned hydrophilic polyester resin and / or hydrophilic polyurethane resin, followed by heat treatment at a temperature of 130 ° C. or lower. .

Particularly, the washing method of the present invention is preferably sterilization washing in which hot water treatment is performed in the presence of chlorine. Such sterilization washing process, 60 ℃ or 80 ℃
Generally, washing with hot water for 10 minutes or more and washing with a free chlorine concentration of 250 mg / liter or more are preferably used as the main washing steps, and then a detergent washing step and a drying step are generally performed.

The treatment step of the present invention can be performed by dipping in the washing step after the main washing step, spraying before the drying step, spraying in the dryer during the drying step, etc.
In consideration of the labor and time required for the treatment, the immersion is most preferable in the final step of the cleaning step. The concentration during the treatment is preferably in the range of 0.025 to 2.0% by weight. When the concentration of the treatment liquid is too low, the treatment tends to have to be repeated many times in order to exhibit the water absorption performance. On the contrary, when the concentration is higher than 2.0% by weight, the low temperature treatment as in the present invention makes it impossible to sufficiently fix the fibers to the fibers and the durability tends to be lowered. Then, dehydration treatment is performed thereafter, and the final adhesion amount of the hydrophilic polyester resin and / or the hydrophilic polyurethane resin is 0.001% by weight to the water-absorbent article treated with the resin.
It is preferable to deposit 5.0% by weight. More preferably, 0.01 wt% or more is preferably attached.

Next, in the washing method of the present invention, the water-absorbent article to which the hydrophilic resin is attached is 140 ° C. or lower, preferably 1
The heat treatment is performed at 30 ° C. or lower, most preferably 60 to 120 ° C. When the treatment is performed at a temperature higher than 140 ° C., the water-absorbent article is deteriorated, which is unsuitable as a treatment that needs to be repeated many times. Further, at a temperature lower than 60 ° C., the adhesion to the fiber tends to be weak, and the heat treatment time tends to be too long. As a method of such treatment, for example, a tunnel dryer is used, and the temperature of the hot air outlet is set to 1
It is realized by setting the temperature below 40 ° C. The preferable heat treatment time depends on the thickness of the water absorbent article, the basis weight, etc.
It takes time for the water-absorbent article to be sufficiently dried, but not to be overdried. For example, when a tunnel dryer is used, the temperature of the air discharged from the drum is low to 90 ° C., more preferably Is obtained by drying from low temperature to 80 ° C.

The water-absorbent article obtained by using such a method for washing a water-absorbent article of the present invention has sufficient water-absorbing performance even after washing. The preferred range of water absorption performance is to maintain the initial value of water absorption performance.
The L1018A method (dropping method) is 10 seconds or less, and most preferably 1 second or less. Furthermore, the water-absorbent article obtained by this washing method has a low slimy feel when it comes into direct contact with the skin, has an excellent feeling, and has excellent performances such as stain resistance and antistatic property. A preferable value of antistatic property is a value measured by a friction electrification voltage measurement method of JIS L1094, and is in a range of 1000 V or less, more preferably 250 V or less.

Therefore, according to the method for washing water-absorbent articles of the present invention, the water supply performance does not deteriorate even after repeated re-washing, and it is suitable for washing bed sheets, pillowcases, yukatas, etc. used in hospitals and hotels. This is a suitable method, and is the most suitable washing method for diapers, hospital clothes, etc. used in hospitals and the like.

[0021]

EXAMPLES The present invention will be described below with reference to examples.
The invention is not limited to this example.
In the examples and comparative examples, the evaluation method was measured by the following method.

(1) Water-absorbent article used The water-absorbent article used was a tricot 2 bar knitting machine, with 56 decitex / 24 filament polyethylene terephthalate multifilament yarn arranged on the back reed with a structure of 10/12. Knit the ground structure and arrange the 139 decitex / 24 filament polyethylene terephthalate multifilament yarn on the front reed and
A knitted fabric with a 0/45 satin structure is knitted into a ground structure, and a loop having a height of 3 mm is formed on the surface of the knitted fabric. , By cutting a part of the loop, the loop and the fluff are mixed on the surface, and the density in the warp direction is 46 /
2.54 cm (inch), density in the weft direction is 44 / cm
I got a (inch) knitted fabric. Further, the knitted fabric is subjected to a hydrophilic treatment to obtain an initial water absorption rate of 1 second or less and a friction electrification voltage of 16
The knitted fabric of V was used as a test cloth.

(2) Laundry test The washing machine uses Poesgen PWZ501-10D (10-layer continuous washing machine manufactured by Asahi Seisakusho Co., Ltd.). (November 25, 1993) in accordance with the washing by a continuous washing machine (method of using a chlorine agent having a disinfecting effect during the washing process). Then, after dehydration was carried out by a hydraulic dehydrator (ASP-350, manufactured by Asahi Seisakusho), it was dried using a tunnel dryer (APT-3120, manufactured by Asahi Seisakusho).

(3) Water absorption speed The water absorption speed was measured based on the dropping method of JIS L1018 A method (dropping method). The test cloth was placed horizontally, one drop of pure water was dropped on the test cloth, and the time (second) until the water drop was completely erased from the surface of the test cloth was measured.

(4) Resistance to recontamination The resistance to recontamination was evaluated by having the same patient wear a test cloth, subjecting the cloth to a washing treatment with the excrement adhering to it, and visually examining the removal of excrement. Recontamination ○: Manure was completely removed. Δ: The excrement was removed, but a trace of slight adhesion was seen. ×: excrement remained.

(5) Antistatic property The antistatic property was measured by the friction electrification voltage measuring method of JIS L1094. The average value of the measurements in the vertical and horizontal directions was used for evaluation.

[Example 1] SR-1000 manufactured by Takamatsu Yushi Co., Ltd., which is a hydrophilic polyester resin, was added to the 10th layer of the continuous washing machine, which is the final step of the washing step, to obtain 0.1%.
The test cloth was treated with an aqueous solution concentration. The wet pickup after hydraulic dewatering was 40%. Further, the hot air outlet temperature of the dryer was set to 130 ° C., and the drying treatment was performed until the temperature of the outlet increased from a low temperature to 80 ° C. The temperature inside the drum was maintained at 120 ° C. or lower. Table 1 shows the water absorption rate, the redeposition resistance, and the antistatic property of the test cloth after the treatment. The test cloth had little slimy properties and excellent texture even after washing tests of 10 and 20 times, and was excellent in water absorption performance, anti-soil redeposition property, and antistatic property.

[Example 2] As in Example 1, the hydrophilic polyurethane resin Evaphanol N-20 manufactured by Nichika Kagaku Co., Ltd. was added to the 10th layer of the continuous washing machine to obtain 0.05%.
The test cloth was treated with an aqueous solution concentration. The wet pickup after hydraulic dewatering was also the same as in Example 1. Further, the same drying treatment as in Example 1 was performed. Table 1 shows the water absorption rate, the redeposition resistance, and the antistatic property of the test cloth after the treatment. The test cloth had little slimy properties and excellent texture even after washing tests of 10 and 20 times, and was excellent in water absorption performance, anti-soil redeposition property, and antistatic property.

[Comparative Example 1] As in Example 1, the 10th layer of the continuous washing machine contains a quaternary ammonium salt as a main component and ethylene glycol or the like as a performance-improving agent mixed with Lion Corporation. The water-absorbing softening agent Softes Co., Ltd. was added and the test cloth was treated with a 0.1% aqueous solution concentration. Also,
The wet pickup after hydraulic dewatering was also the same as in Example 1. Further, the same drying treatment as in Example 1 was performed. Table 1 shows the water absorption rate, the redeposition resistance, and the antistatic property of the test cloth after the treatment. Although the test cloth was excellent in feeling, the water absorption performance was deteriorated as the number of washing tests was increased, and the performance was also deteriorated in stain resistance and antistatic property.

[Comparative Example 2] A washing test was carried out without adding anything to the 10th layer of the continuous washing machine which is the final step of the washing step. Table 1 shows the water absorption rate, the redeposition resistance, and the antistatic property of the test cloth after the treatment.

[0031]

[Table 1]

[0032]

EFFECTS OF THE INVENTION The washing method of the present invention provides a water-absorbing article which has good texture and is reusable, even if the water-absorbing article containing synthetic fibers is repeatedly washed. Is the way.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) // A61F 5/44 D06M 101: 32 D06M 101: 32 15/507 AF term (reference) 3B155 AA12 AA15 AA21 AB01 AB07 BB00 GA00 GA25 3B201 AA08 BB02 BB82 BB95 4C058 AA03 BB03 BB07 BB09 CC06 JJ01 JJ08 JJ16 JJ21 4C098 AA09 CD03 DD08 DD09 DD10 DD16 DD23 DD26 DD27 DD28 4L033 AA07 AB04 AC07 CA45 CA51 DA

Claims (3)

[Claims] 1. In the washing of a water absorbent article containing synthetic fibers, it is treated with an aqueous solution containing a hydrophilic polyester resin and / or a hydrophilic polyurethane resin, and then 140 ° C.
A method for washing a water absorbent article, comprising a step of heat treatment at the following temperature. 2. The method for washing a water absorbent article according to claim 1, wherein the washing is a sterilization washing in which hot water treatment is performed under a chlorine content. 3. The method for washing a water absorbent article according to claim 1, wherein the synthetic fiber is a polyester fiber.