JP2003079660A - Film for sanitary article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film for a sanitary article which is excellent in water resistance and mechanical strength and is soluble in water immediately. SOLUTION: The film for a sanitary article is used which comprises a base film made from a modified polyvinyl alcohol-based resin having a saponification degree of 95 mol% or more and containing an ethylene content of 3-40 mol%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hygiene product film which is preferably used as a back sheet for hygiene products.

[0002]

2. Description of the Related Art Conventionally, a film having both water solubility, water resistance and strength is useful in various fields such as sanitary goods, cleaning sheets, agricultural films, food packaging films and general packaging films. Film development is desired. In particular, for sanitary products such as sanitary napkins and absorbent sheets for absorbent articles, there is a demand for a film that does not cause clogging of pipes even when flushed in a toilet after use and has a small load on a septic tank.

In a sanitary article, a body fluid absorbent member is generally sandwiched between and wrapped by a body fluid permeable top sheet and a body fluid impermeable back sheet, and the hygiene article is fixed to underwear on the outer surface of the back sheet. The adhesive layer for doing is provided. FIG. 1 is a sectional view schematically showing a conventional sanitary article. In the figure, 1 indicates a hygiene article, which has a configuration in which a body fluid permeable topsheet 11, a body fluid absorbent member 12, a body fluid impermeable backsheet 13, and an adhesive layer 14 are laminated in this order, Further, a release paper 15 is temporarily fixed on the adhesive layer 14.

The above-mentioned sanitary products are discarded after use, but conventionally, as a whole, a non-water-decomposable member is often included as a whole. It is often used, and there is a problem in that it causes pipe clogging when flushed to the toilet.

As a method for solving this problem, for example, Japanese Patent Application Laid-Open No. 9-272719 discloses a film made of polyvinyl alcohol having excellent water solubility.
However, although the above-mentioned film is excellent in water solubility, when it is used as a back sheet of a sanitary article, for example, there is a problem in that the water resistance is insufficient and the film swells due to sweat, body fluid, etc. and its strength is reduced.

[0006]

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, the present invention is excellent in water resistance and mechanical strength, and
It is intended to provide a film for hygiene products that quickly dissolves in water.

[0007]

The film for hygiene articles of the present invention has a saponification degree of 95 mol% or more and an ethylene content of 3 to 3.
40 mol% of modified polyvinyl alcohol resin (hereinafter,
It is characterized by comprising a base film made of modified PVA).

Examples of the modified PVA constituting the above-mentioned substrate fill include ethylene-vinyl alcohol copolymer and the like.

When the ethylene content of the ethylene-vinyl alcohol copolymer is low, the water resistance of the hygiene product film is low, and when it is high, the hydrophilicity of the hygiene product film is low. It is limited and is preferably 3 to 20 mol%.

When the saponification degree of the modified PVA becomes low,
The water resistance of the hygiene article film decreases, the mechanical strength decreases due to moisture, and the water solubility increases, so the content is limited to 95 mol% or more. Incidentally, the water-soluble in the present invention,
It means dissolution in water with a large amount of water flow, and the saponification degree is a value measured according to JIS K 6726.

If the degree of polymerization of the above-mentioned modified PVA becomes large, the water solubility of the hygienic product film decreases, and extrusion molding becomes difficult in the manufacturing process, and if it becomes small, the water resistance and mechanical strength of the hygienic product film decrease. However, since extrusion molding becomes difficult, 300 to 600 is preferable. Further, when higher moldability is required, it is preferable that a modified PVA having a higher degree of polymerization is mixed with the modified PVA. If the degree of polymerization of the modified PVA having a higher degree of polymerization becomes larger, extrusion molding becomes difficult.
Is preferred. The degree of polymerization is a value measured according to JIS K 6726. Modified P with higher degree of polymerization
The amount of VA mixed is preferably 5 to 50% by weight, because if it increases, extrusion molding becomes difficult and a base film becomes difficult to obtain, and if it decreases, the mixed effect cannot be obtained.

If desired, a polyhydric alcohol may be added to the modified PVA in order to improve the flexibility of the hygienic film. Examples of the polyhydric alcohol include dihydric alcohols such as ethylene glycol, diethylene glycol, triethylene glycol and polyethylene glycol; trihydric alcohols such as glycerin; tetrahydric alcohols such as diglycerin; and polyglycerin. . These may be used alone or in combination of two or more. Further, among these polyhydric alcohols, glycerin or diglycerin has good compatibility with the modified PVA, and the flexibility of the hygiene article film is excellent, and the amount of smoke generated when the modified PVA is extrusion-molded is small. It is preferable because it has excellent properties.

The amount of the polyhydric alcohol added is appropriately determined according to the intended use and the required flexibility, but when the amount is low, the flexibility of the hygiene product film decreases, and when it is high, the hygiene product film is added. Since the water resistance decreases and it easily bleeds out on the film surface and transfers to the contact object,
The amount is preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, based on 100 parts by weight of the modified PVA.

The method for producing the substrate film is not particularly limited, but if necessary, additives such as polyhydric alcohol are added to the modified PVA, and a kneader mixer, a kneading roll or the like is used in a conventionally known kneading apparatus. After melt-kneading, a method of supplying the kneaded product to an extruder and extrusion-molding a film having a predetermined thickness from a mold such as a T-die attached to the tip of the extruder is preferable. The melt kneading may be performed in an extruder.

In the above-mentioned extrusion molding method, the production process is usually good because the drying step required for the casting method applied to polyvinyl alcohol resins is not required, and
Since the thickness and the tensile strength can be easily adjusted, for example, a thin base film having a thickness of 30 μm or less can be easily manufactured.

In the above extrusion molding, the film extruded from the mold is wound on a roll while being cooled. When the film is wound, tension is applied by adjusting the speed of the roll, and the film extrusion direction (MD). And MD
It is preferable to adjust the tensile strength in the direction orthogonal to (TD). The tensile strength in both directions can be appropriately determined depending on the application.

The basis weight of the above-mentioned base film is appropriately determined according to the use, but when it is small, it becomes difficult to manufacture the film, and when it is large, the film becomes too stiff and is used as a back sheet for sanitary goods. because feeling is lowered when used, preferably from 5 to 100 g / m ^2, more preferably from 10 to 40 g / m ^2.

The above-mentioned substrate film is preferably used as a laminated film in which a water-decomposable substrate is laminated and integrated on one surface in order to improve the water-decomposability.

The above-mentioned water-decomposable substrate is preferably a sheet-like material having water-decomposability, and for example, a fibrous body made of water-decomposable fibers in which the fibers are separated from each other in the entangled state in water. Among them, non-woven fabric is preferable. Examples of the water-decomposable fiber include pulp, rayon, cupra, cotton, hemp, wool and silk, and among them, pulp is preferable.

The water-decomposable fiber may be bound with a water-soluble binder. Examples of the water-soluble binder include cellulose-based resins such as polyvinyl alcohol, methyl cellulose, and hydroxyethyl cellulose; starch, sodium alginate, sodium polyacrylate, polyacrylic acid ester, and the like.

In addition to the above non-woven fabric, a sheet in which short fibers made of synthetic resin are bound to each other by a water-soluble binder can be used as long as it has water-decomposability. Examples of the synthetic resin include polyethylene-based resin, polypropylene-based resin, polyester-based resin, polyamide-based resin, and the like. As the water-soluble binder, those similar to those used for the nonwoven fabric are used.

When the basis weight of the water-decomposable substrate is small, the strength is low, and it becomes difficult to process it into a laminated film. When it is large, the water-decomposability of the laminated film is low.
100 g / m ² is preferred.

The method for laminating and integrating the water-decomposable base material on the base material film is not particularly limited. For example, the modified PVA is attached to the tip of the extruder from a mold such as a T-die to a predetermined thickness. It is preferable that the film is extruded and laminated on a water-decomposable substrate.

The above-mentioned extrusion lamination method generally does not require water as in the casting method applied to the above-mentioned modified PVA. Therefore, when the above-mentioned modified PVA film and the water-decomposable substrate are laminated and integrated, the It is possible to easily and surely laminate and integrate the flexible substrate without being decomposed by water. In addition, in the method by extrusion lamination, the drying step required for the casting method or the like is unnecessary, so that the production efficiency is good, and since the thickness and the tensile strength are easily adjusted, for example, the modified PVA film having a thickness of 30 μm or less is used. Can be easily laminated on the water-decomposable substrate.

Further, in the method of extrusion lamination,
Since the modified PVA film and the water-decomposable substrate are laminated and integrated on the entire surface, in the obtained laminated film, the dispersibility of the water-decomposable substrate, which is easily dispersed in water, promotes the water-decomposability of the modified PVA film and is laminated. The film quickly hydrolyzes.

Except for the above method, extruded modified PVA
The film may be partially adhered to one surface of the water-degradable substrate with an adhesive to form a laminated film. In addition, when water resistance is more required, one surface of the modified PVA film may be coated with a water-insoluble resin.

The base film or laminated film of the present invention can be suitably used as the backsheet 13 of the conventional sanitary article 1 shown in FIG. That is, the body fluid absorbent member is sandwiched and surrounded by the back sheet and the top sheet, and the pressure-sensitive adhesive layer is formed on the surface of the back sheet opposite to the body fluid absorbent member side, thereby forming a sanitary article.

Since the above-mentioned base film or laminated film has water solubility but also excellent water resistance, it is impermeable to a small amount of water such as body fluid and sweat.

The surface sheet is preferably a sheet having water disintegratability and body fluid permeability, and specific examples thereof include the same as those used as the water disintegratable substrate. Further, when the basis weight of the surface sheet is small, the strength is low, and the surface sheet is easily broken when the hygiene product is used, and when it is large, the wearing feeling of the hygiene product is deteriorated.
˜100 g / m ² is preferred.

The body fluid absorbing member preferably has water-disintegrating property and body fluid-absorbing property, and specific examples thereof include the same as those used as the above-mentioned water-decomposable base material. If the basis weight of the body fluid absorbing member is small, the body fluid absorbency of the sanitary article is reduced, and if it is large, the hygiene article becomes too stiff and the wearing feeling is reduced.
100 g / m ² is preferred.

As the above-mentioned pressure-sensitive adhesive, any conventionally known one can be used, and for example, an acrylic pressure-sensitive adhesive is preferably used.

[0032]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples of the present invention, but the present invention is not limited to these Examples.

(Examples 1 and 2, Comparative Examples 1 and 2) The ethylene-polyvinyl alcohol copolymer (hereinafter referred to as EVOH) having a predetermined blending amount shown in Table 1 (polymerization degree, saponification degree and ethylene content are (Each shown in Table 1) was put into an extruder, melt-kneaded at 220 ° C., and then a T-die (lip width 500 mm, clearance 0.
5 mm) and extruded at a speed of 30 m / min and a thickness of 30
A film for hygiene products having a thickness of μm and a basis weight of 35 g / m ² was obtained.
Incidentally, EVOH (1) was used alone in Example 1 and Comparative Examples 1 and 2, and EVOH (1) and (2) were used in combination in Example 2.

(Embodiment 3) As in Embodiment 2, EVOH
(1) and (2) are charged into an extruder and melt-kneaded at 220 ° C., and a T-die (lip width 500 mm, clearance 0.
5 mm) and extruded at a speed of 30 m / min, the basis weight is 15
Laminated on one side of a g / m ² pulp non-woven fabric, basis weight 3
A hygienic film comprising a laminated film of 5 g / m ² was obtained.

The following items were evaluated for the films for hygiene products obtained in the above Examples and Comparative Examples, and the results are shown in Table 1. (1) Water decomposability Based on JIS P 4501, the ease of loosening was evaluated.

(2) A water resistant cylinder having a diameter of 92 mm was placed on a horizontal desk with its opening facing upward, and a film for sanitary goods was placed in this opening so as to cover all of the opening and tensioned. I put it up so that I wouldn't put it on. When the hygiene product film was a laminated film with a nonwoven fabric, the nonwoven fabric was stretched so as to face the cylinder side. Next, after dropping 0.1 cm ³ of water droplets on the center of the stretched hygiene product film, a 5.5 g weight was placed on the dropped portion and left to stand. And the time until it fell was measured.

[0037]

[Table 1]

[0038]

EFFECT OF THE INVENTION The hygiene article film of the present invention has the above-mentioned constitution, is excellent in strength and shows excellent water solubility in a large amount of water flow, and shows excellent water resistance in a small amount of water. Moreover, the strength is not lowered by absorbing water. In the film for hygiene products of the present invention, the disintegrating power of the water-decomposable base material in water promotes the water-disintegration of the modified PVA film and the water-decomposable base material is rapidly hydrolyzed in water. . Therefore, the film for hygiene products of the present invention is preferably used as a back sheet of hygiene products which requires water resistance and strength during use and may be washed with water after use.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a conventional sanitary article.

[Explanation of symbols]

1 sanitary goods 11 Surface sheet 12 Body fluid absorbent material 13 Back sheet 14 Adhesive layer 15 Release paper

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4C003 CA06 CA07 HA04                 4F100 AK69A AR00B AT00A DG01B                       DG02B EH17 EH23 GB15B                       GB72 JB07 JB09 JB09B                       JK01 YY00A

Claims (2)

[Claims] 1. A hygienic film comprising a base film made of a modified polyvinyl alcohol resin having a saponification degree of 95 mol% or more and an ethylene content of 3 to 40 mol%. 2. The film for sanitary goods according to claim 1, wherein a water-decomposable substrate is laminated on one surface of the substrate film.