JP3193733B2 - Liquid-impervious leak-proof sheet for disposable body fluid treatment products - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leak-proof sheet used for a back sheet of a disposable body fluid treatment article, and more particularly to a liquid-impervious leak-proof sheet having excellent elasticity and cloth-like feel. .

[0002]

BACKGROUND OF THE INVENTION disposable fluid processing products represented in training pants and disposable diapers, generally, a liquid-permeable top sheet and a liquid-impermeable back sheet, and in the case of many, the absorber between these And a basic configuration. To the backsheet liquid-impermeable uses liquid-impervious leak-barrier sheet, as the sheet, facilities hydrophobic plastic film, a rubber sheet, a nonwoven fabric and it water-repellent treatment of hydrophobic fibers Such materials are known as conventional materials. The shape of the disposable diaper includes an open type and a pants type. Pants-type diapers and other pants-type disposable body fluid treatment products should have good fit during wear,
It has advantages such as less leakage of bodily fluids around the legs and waist caused by this, and easy wearing operation.
However, it is not always easy to exert all of these advantages at the same time.

[0003]

In a pants-type disposable body fluid treatment article as described above, if a conventional material is used for the liquid-impervious leak-proof sheet, a plastic film does not have sufficient elasticity. Good fit cannot be obtained. In addition, the feeling peculiar to the plastic film is generally disliked by consumers. In the case of a rubber sheet , excellent elasticity is obtained, but the feel is disliked like a plastic film. The appearance is far from giving the wearer a favorable impression, and rubber materials are generally expensive. Although it is conceivable to improve the feel and appearance by using a clothed rubber, it is difficult to adopt this in this field where cost competition is severe. In the case of a nonwoven fabric , the feel is good, but the stretchability is insufficient, good fit cannot be obtained, and leakproofness is not sufficient.

[0004] In view of the above situation, the present invention provides a liquid-impervious leakproof sheet that is suitable for use as a backsheet for disposable body fluid treatment articles by joining a stretchable film and a stretchable nonwoven fabric. It is an object.

[0005]

[MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The present invention provides a stretch film having a basis weight of 10 to 30 g / m ^2.
And a stretchable nonwoven fabric having a basis weight of 25 to 45 g / m ²
5-20% of the product is intermittently joined at the rate of
A disposable that uses a cloth positioned outside the body fluid treatment product
In the liquid-impervious leak-proof sheet of a body fluid treatment article,
Elongation stress at 50% elongation in the longitudinal direction
Elongation of stretchable film at 50% elongation in the machine direction
Greater than the force, elongating the stretchable film by 50% in the machine direction.
The permanent set after elongation is 50% elongation of the stretchable nonwoven fabric in the machine direction.
Smaller than the permanent set after long, and the elastic nonwoven fabric
Is a non-woven fabric containing crimped fibers, and the fibers are hydroentangled.
At one point.

[0006] In the present invention, the term "longitudinal direction" means a nonwoven fabric.
/ Film produced on machine line or later processed
The nonwoven / film along the line.
Direction (MD).

[0007]

When the backsheet is constituted by the leak-proof sheet according to the present invention constituted as described above, the elasticity of the elastic film and the elastic nonwoven fabric cooperate with each other due to intermittent joining of the body fluid. The elasticity suitable for the processing article can be obtained. The leak-proof sheet is liquid-impermeable and stretchable due to the presence of the stretchable film. The presence of the stretchable nonwoven fabric gives the leakproof sheet a cloth-like feeling, and its relatively large elongational stress acts to prevent the stretchable film from being unnecessarily stretched. Accordingly, the body fluid treatment article using the leak-proof sheet for the back sheet is excellent in not only leak-proof property but also fit and appearance. Such features according to the present invention are particularly well exhibited when the body fluid treatment article is a pants type. In particular, the elongation stress of the nonwoven fabric is
With the article due to the low elongation stress of the film
To compensate for the disadvantages, such as fit lack of, and the full
Due to the large elongation of the nonwoven fabric
To compensate for defects such as the appearance of large wrinkles as the article
And the non-woven fabric is a melt bond,
Fusion of fibers such as tobron, and fiber bonding via a binder
Different from those that maintain the sheet form depending on the case, the fiber
The sheet shape is maintained by mechanical entanglement by water flow.
Therefore, while having excellent cloth-like feel,
Even if a relatively large elongation set is generated during wear,
Uniformly shrinks with the lum and recovers almost to the original appearance
And maintain a given bulkiness and drape,
The wrinkles and looseness are caused, and the fluff is caused by fiber breakage.
No appearance occurs, and the appearance and fit are excellent.

[0008] The leakproof sheet according to the present invention is applied to the illustrated embodiment.
Therefore, it will be described as follows.

[0009]

FIG. 1 shows a pants-type disposable diaper 1 in which a leak-proof sheet according to the present invention is used as a back sheet 15. The diaper 1 includes a top sheet 9, a back sheet 15, and an absorber 12 interposed therebetween.
(See FIG. 2 described later). An elastic sheet 4 as a leg elastic member, a plurality of thread rubbers 6 as a waist elastic member, and a plurality of thread rubbers 5 as a waist elastic member.
You .

FIG. 2 is a developed view schematically showing the shape of each member for obtaining the diaper 1 of FIG. The topsheet 9, the backsheet 15, and the absorbent body 12 have a conventional hourglass shape in a disposable diaper. Absorber 12 is intermittently adhered to the back surface of top sheet 9 with a hot melt adhesive (not shown), and back sheet 15 is further covered with top sheet 9 so as to cover absorber 12.
And is adhered to the periphery of the top sheet 9 with a hot melt adhesive (not shown). On the surface of the back sheet 15 facing the top sheet 9, elastic members 4, 5, and 6, which are under extension, are respectively bonded by a hot melt adhesive. After all of these bondings have been performed, the front and rear waist portions 13 , 14 are bent in two in the vertical direction so as to contact with each other, and the front and rear waist portions 13 , 14 are bent .
14 are joined by the heat-sealing wire 7 (see FIG. 1).
A diaper 1 is formed. In this diaper 1, the front and rear torso
The top located at the crotch between the surrounding parts 13 and 14
Notch 1 of each of sheet 9 and back sheet 15
Numeral 6 forms a leg circumference 2 (see FIG. 1). Around the torso
The elastic member 6 is located below the front and rear waist parts 13 and 14.
And the excreta excreted in the crotch
Machine that prevents fluid from flowing to the waist and leaking from around the waist
Has ability.

The top sheet 9 is a liquid-permeable non-woven fabric made of polyethylene, polypropylene, or other thermoplastic fibers, and is preferably made of an elastic material. The absorber 12 is a compression molded product of ground pulp containing 10% by weight of superabsorbent polymer particles. The back sheet 15 is formed of the leak-proof sheet according to the present invention.

FIG. 3 is an end view taken along the line X--X in FIG. In the figure, a back sheet 15 is a stretch film 11 at a position facing a top sheet 9 and a hot melt adhesive 1
The diaper 1 is made of a stretchable nonwoven fabric 10 which is intermittently adhered to the diaper 1 via an intermediary 7. The film 11 and the nonwoven fabric 10 are adhered so that their longitudinal directions (hereinafter, referred to as MD) substantially coincide with each other. This MD is a diaper 1
In the vertical direction. The elastic film 11 imparts liquid impermeability and excellent elasticity to the back sheet 15, and is a thermoplastic elastomer obtained by using a thermoplastic polymer such as polyethylene or polypropylene as a hard phase and a rubber component as a soft phase. (TPE) is suitable in terms of stretchability, cost, workability, storage stability, and the like. Also,
Such a stretchable film 11 has a basis weight of 10 to 30 g / m ^2.
And the elongation stress at the time of MD 50% elongation is 150 to 400 g /
(100 mm length × 25 mm width) is appropriate. If the basis weight is less than 10 g / m ² , the thickness of the film becomes thin, the strength becomes insufficient, and the elongation stress tends to be insufficient, so that it is difficult to realize the good fit of the diaper 1. 30g
If the basis weight exceeds / m ² , the elongation stress becomes large and excessive quality and high cost are undesirably caused. Non-woven fabric 10
Suppresses stretching of the elastic film 11 when the diaper 1 is about to be worn and during wearing, imparts a moderate elongation stress to the back sheet 15, and softens the feel of the diaper 1. The purpose is to make it feel like a bulky cloth. For this purpose, the nonwoven fabric 10 has some elasticity and has a larger elongation stress than the film 11. It has a basis weight of 25 to 45 g / m ² , MD
The elongation stress at 50% elongation is larger than that of the film 11 700 to 1500 g / (100 mm length × 25 mm width)
It is preferable to have As such a stretchable nonwoven fabric, for example, a nonwoven fabric containing at least 80% by weight of a fiber formed by thermally crimping a composite fiber of polyethylene and polypropylene or a composite fiber of polypropylene and modified polypropylene having a fineness of 1 to 7d, more preferably Such heat crimped fiber 8
A nonwoven fabric consisting of 0 to 100% by weight and having fibers entangled under the action of a high-pressure jet stream is preferred. The bonding area between the film 11 and the nonwoven fabric 10 is 5 to 20% by a soft adhesive such as a soft hot melt adhesive 17 at normal temperature.
Are intermittently joined so as to occupy. Such intermittent joining is performed, for example, by applying an adhesive in the form of dots or lines, and is generally preferably in the form of dots, but is preferably intermittent if it is linear. An excessively small bonding area makes it difficult to realize integral expansion and contraction of the film 11 and the nonwoven fabric 10, while an excessively large bonding area increases the elongation stress of the back sheet 15 and undesirably impairs feel. . However, functionally, the back sheet 15 may have a locally high bonding area ratio of 20% or more.

Further, regarding the film 11, 5
It is preferable to use one having a permanent set of 15% or less when stretched by 0%. On the other hand, the nonwoven fabric 10 only needs to have this permanent set of about 20 to 50%. When the diaper 1 is worn, the nonwoven fabric 10 stretches beyond the limit of elastic deformation,
Even if a large permanent distortion is generated, the nonwoven fabric 10 is wrinkled and shrinks together with the shrinkage of the film 11. So diaper 1
Can provide a good fit to the wearer and a slack-free appearance.

Table 1 shows the back sheet 1 shown in FIGS.
5 shows the configuration and physical properties of the leakproof sheet according to the present invention, which is suitable for use in No. 5, together with Comparative Examples. The leakproof sheet is made of a core-sheath type composite fiber of polypropylene and modified polypropylene made into a non-woven fabric by high-pressure jet water flow, and then heat-treated and crimped. It is configured by intermittent joining with a hot melt adhesive.
The non-woven fabric before crimping has a basis weight of 20 g / m ² , and the crimping ratio is changed by changing the heat treatment temperature and time to obtain non-woven fabrics having various basis weights shown in Table 1. .

[0015]

[Table 1]

[Brief description of the drawings]

FIG. 1 is a perspective view of a pants-type disposable diaper using a leak-proof sheet according to the present invention as a back sheet.

FIG. 2 is an exploded perspective view showing the configuration of the diaper of FIG.

FIG. 3 is an end view taken along line XX in FIG. 2;

[Description of Signs] 1 Body fluid treatment article 9 Top sheet 10 Elastic non-woven fabric 11 Elastic film 15 Leak-proof sheet (back sheet)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-212357 (JP, A) JP-A-63-203805 (JP, A) JP-A-63-28960 (JP, A) 41006 (JP, U) Hikaru 1-164707 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) A61F 13/514

Claims (5)

(57) [Claims] (1)Basis weight 10-30g / m ² Stretch film
And basis weight 25-45 g / m ² The joint surface with the elastic non-woven fabric
5-20% of the product is intermittently joined at the rate of
A disposable that uses a cloth positioned outside the body fluid treatment product
In liquid-impervious leak-proof sheets for body fluid treatment products, Elongation resistance when the stretchable nonwoven fabric is stretched by 50% in the machine direction.
The force is applied when the stretchable film is stretched by 50% in the machine direction.
Greater than the elongation stress Permanent set after stretching the stretchable film by 50% in the machine direction
Is the permanent set of the stretchable nonwoven fabric after elongation by 50% in the machine direction.
Smaller than and The stretchable nonwoven fabric contains crimped fibers, and the fibers
Non-woven fabric entangled The leak-proof sheet
G. 2. The stretchable nonwoven fabric according to claim 2 , wherein the elongation stress is 700.
~ 1500g / (100mm length x 25mm width)
And, the elongation stress of the stretchable film is 150-4.
2. The amount is 00 g / (100 mm length × 25 mm width).
The leakproof sheet as described. 3. The stretchable film according to claim 1 , wherein the permanent set is 15 or more.
% Or less and the permanent set of the elastic nonwoven fabric
The leakproof sheet according to claim 1, wherein the ratio is 20 to 50%. 4. The crimped fiber in the stretchable nonwoven fabric
The leak-proof sheet according to claim 1, wherein the content is 80% by weight or more.
G. 5. The fiber according to claim 1, wherein said fiber is heat-crimped.
Item 7. The leakproof sheet according to Item 1.