JPH0987405A - Film for individual packaging of sanitary napkins - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To have excellent heat resistance while being thin and flexible. SOLUTION: At least one side of a polypropylene film is treated with silicone, and the tensile modulus of the silicone-treated polypropylene film is 25 Kgf / mm ² or less in both longitudinal and transverse directions, and a melting temperature of DSC measurement of 130 ° C or more. Characterize.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a film for an individual wrapping body of a sanitary napkin.

[0002]

2. Description of the Related Art Conventionally, a low-density polyethylene film, which is thin and flexible, has been used for individual packaging of sanitary napkins. This is to prevent noise when the package is opened.

Further, an individual wrapping body having an inner peripheral surface provided with a release agent layer is known. This is because it is not necessary to use release paper for the adhesive layer provided on the back surface of the napkin. Regarding such an individual wrapping body, Japanese Utility Model Publication No. 4-46738 discloses an individual wrapping body for a sanitary napkin in which a release agent layer is formed on the inner peripheral surface of the individual wrapping body that abuts an adhesive layer provided on the back surface of the napkin. Is disclosed.

By the way, as the film for an individual wrapping body as described above, it is not possible to use a low density polyethylene film which is thin and flexible. That is, when a release agent such as silicone is applied and cured to form a release agent layer on one surface of the film corresponding to the inner peripheral surface of the individual package, the curing temperature of the release agent is 140 to 160 ° C.
The pressure-sensitive adhesive layer is formed by applying a hot-melt type pressure-sensitive adhesive on the upper surface of the release agent layer, and the application temperature of this hot-melt type pressure-sensitive adhesive is 140 ° C or higher. This is because the polyethylene film melts or is significantly deformed when placed under such a temperature.

Therefore, Japanese Unexamined Patent Publication No. 61-122861 discloses
It discloses that a film having a multilayer structure of a low melting point film and a high melting point film is used as a film for an individual wrapping body. Polyethylene is used as the material of the low melting point film, and polypropylene and ionomer resin are used as the material of the high melting point film.

[0006] Japanese Utility Model Laid-Open No. 184543/1993 discloses a film for an individual wrapping body using an ultraviolet-curable silicone resin which cures at a low temperature on the surface of the film.

[0007]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The film for an individual wrapping body of No. 2861 has a problem that the manufacturing process becomes complicated and the manufacturing cost becomes high because the multilayer structure is adopted.

Further, since the low melting point film is provided on the outer peripheral surface of the package and the high melting point film is provided on the outer peripheral surface of the package, there is a problem that the method of sealing the package is limited.

On the other hand, the film for an individual wrapping body of Japanese Utility Model Laid-Open No. 3-184543 requires an ultraviolet irradiation device,
Further, there is a problem that a longer curing time is required as compared with the usual heating method.

Further, even if the temperature rise in the curing step of the silicone resin is avoided, when the adhesive layer is formed by applying a hot-melt type adhesive on the upper surface of the release agent layer, the temperature rise of the packaging film is avoided. Therefore, there is a problem that the film for packaging body is melted or is significantly deformed.

In view of the above points, it is an object of the present invention to provide a film for an individual wrapping body which is thin and flexible and has excellent heat resistance and peelability.

[0012]

A film for an individual wrapping body for a sanitary napkin according to the present invention has a polypropylene-based film having at least one side thereof subjected to silicone processing, and the polypropylene-based film subjected to the silicone processing has a tensile modulus of elasticity in the longitudinal and transverse directions. It is characterized in that the melting temperature in both directions is 25 Kgf / mm ² or less and the melting temperature measured by DSC is 130 ° C. or more.

When the tensile elastic modulus is 25 Kgf / mm ² or more, it lacks flexibility and makes a noise when the package is opened.

At a DSC measurement melting temperature of 130 ° C. or less, the packaging film melts in the step of curing the silicone resin and in the step of forming the adhesive layer by applying a hot-melt type adhesive on the upper surface of the release agent layer. Or it deforms remarkably.

The polypropylene film is made of, for example, 20% polypropylene or propylene copolymer.
~ 40 parts by weight, ethylene / propylene copolymer (containing 55% by weight or more of ethylene) 5 to 20 parts by weight, ethylene / propylene copolymer (containing 20 to 40% by weight or more of ethylene) 40 to 75 parts by weight It is obtained by mixing and forming into a film.

Further, an ethylene / propylene / α-olefin copolymer may be used in place of the above ethylene / propylene copolymer (containing 55% by weight or more of ethylene), and an ethylene / propylene copolymer (ethylene An ethylene / propylene / α-olefin copolymer or an ethylene / α-olefin copolymer may be used instead of 20 to 40% by weight or more).

Further, the thickness of the polypropylene film in the present invention is preferably 15 to 50 μm. This is because when the thickness is 15 μm or less, the strength is insufficient, so that the film is broken at the time of silicone processing or stretches in the longitudinal direction and contracts in the width direction. Also, if the thickness is 50 μm or more, the flexibility becomes poor.

The polypropylene film suitable for the film for individual packaging of sanitary napkins of the present invention preferably has a opacity of 40% or more by adding a pigment. This is because if the opacity is less than 40%, the napkin stored in the individual package will be visible from the outside.

Examples of the above-mentioned pigment include titanium oxide, talc, kaolin and the like. In the case of titanium oxide,
2 parts by weight or more is preferable for 100 parts by weight of the material of the polypropylene film.

[0020]

【Example】

(Example 1) Polypropylene elastomer KS-02
3 parts by weight of titanium oxide and 0.2 parts by weight of stearic acid monoglyceride as an antistatic agent are mixed with 100 parts by weight of 5P (manufactured by Highmont), melted at 150 ° C., and extruded with a tubular die to obtain polypropylene having a thickness of 25 μm. A system film was obtained.

This polypropylene film was subjected to corona discharge treatment so that the wetting tension was 40 dynes, and 0.3 g / m ^{2 of} silicone (KS774 manufactured by Shin-Etsu Chemical Co., Ltd.) was used.
Coating was performed to obtain a film for an individual packaging body of a sanitary napkin.

The tensile elastic modulus of this film for individual wrapping was 20 Kgf / mm ² in both longitudinal and transverse directions, the melting temperature measured by DSC was 158 ° C., and the opacity was 54%.

The peel strength of this individual packaging film is 3
It was as good as 0 g / 50 mm. In addition, a 180 ° C. hot melt adhesive (Esdyne 8620 manufactured by Sekisui Chemical Co., Ltd.
When G) was applied with a width of about 3 mm using a test gun for hot melt, no wrinkles, shrinkage, etc. occurred on this film for individual packaging. Further, the sound when the film for individual packaging body was torn or rolled was small and had a soft feeling.

(Example 2) The polypropylene elastomer KS-052P (manufactured by Highmont) was used in place of the polypropylene elastomer KS-025P (manufactured by Highmont) of Example 1, and a sanitary napkin was prepared in the same manner as in Example 1. To obtain a film for an individual wrapping body.

The tensile elastic modulus of this film for individual packaging was 13 Kgf / mm ² in both longitudinal and transverse directions, the melting temperature measured by DSC was 141 ° C., and the opacity was 58%.

The peel strength of this individual packaging film is 3
It was as good as 0 g / 50 mm. In addition, a 180 ° C. hot melt adhesive (Esdyne 8620 manufactured by Sekisui Chemical Co., Ltd.
When G) was applied with a width of about 3 mm using a test gun for hot melt, no wrinkles, shrinkage, etc. occurred on this film for individual packaging. Further, the sound when the film for individual packaging body was torn or rolled was small and had a soft feeling.

(Comparative Example 1) Low density polyethylene XM07
4-1 (Showa Denko KK) 100 parts by weight, titanium oxide 3 parts by weight, calcium carbonate 14 parts, and stearic acid monoglyceride 0.2 parts by weight as an antistatic agent are mixed and melted at 170 ° C., Extruded with a tubular die,
A polyethylene film having a thickness of 25 μm was obtained.

Example 1 was applied to this polyethylene film.
Silicone processing was performed in the same manner as in 2 to obtain a film for an individual package of a sanitary napkin.

The tensile elastic modulus of this film for individual wrapping was 15 Kgf / mm ² in both longitudinal and transverse directions, the melting temperature measured by DSC was 112 ° C., and the opacity was 50%.

The peel strength of this film for individual packaging is 3
Although it was as good as 0 g / 50 mm, when a 180 ° C. hot melt adhesive (Esdyne 8620G manufactured by Sekisui Chemical Co., Ltd.) was applied with a width of about 3 mm using a test gun for hot melt, the film for this individual package was Wrinkles and shrinkage occurred. The sound when the film for individual wrapping body was torn or rolled was small and had a soft feeling.

(Comparative Example 2) Low density polyethylene XM07
4-1 (Showa Denko KK) 70 parts by weight, high density polyethylene 5050 (Showa Denko KK) 30 parts by weight, titanium oxide 3 parts by weight, calcium carbonate 14 parts, and stearic acid monoglyceride as an antistatic agent. 0.
2 parts by weight were mixed, melted at 190 ° C. and extruded with a tubular die to obtain a polyethylene film having a thickness of 25 μm.

Example 1 was applied to this polyethylene film.
Silicone processing was performed in the same manner as in 2 to obtain a film for an individual package of a sanitary napkin.

The tensile elastic modulus of this film for an individual wrapping body was 34 Kgf / mm ² in both longitudinal and transverse directions, the melting temperature measured by DSC was 131 ° C., and the opacity was 50%.

The peel strength of this film for individual packaging is 2
Good as 8g / 50mm and 180 ℃ hot melt adhesive (Esdyne 8620G manufactured by Sekisui Chemical Co., Ltd.)
Was applied with a test gun for hot melt to a width of about 3 mm, and no wrinkles, shrinkage or the like was generated on the film for individual packaging. However, this film for an individual wrapping body had a rugged feel, and when it was torn or rolled, the sound was loud.

The tensile elastic modulus of each of the examples and comparative examples was measured according to JIS-K7127.

Further, the opacity was measured by a Photovolt type digital white photometer (TC-6D: manufactured by Tokyo Denshoku Co., Ltd.).

Further, the melting temperature measured by DSC is as follows: heating to 180 ° C. at a heating rate of 10 ° C./min, holding for 10 minutes, cooling to 40 ° C. at 10 ° C./min, and then 1 ° C. at 10 ° C./min.
By raising the temperature to 80 ° C., the highest melting peak temperature among the melting peak temperatures could be measured.

Further, the peeling strength is determined by the adhesive (BPS manufactured by Toyo Ink Co., Ltd.) on the silicone coated surface of the film.
-8170 is applied to a thickness of 100 μm (including solvent),
After drying for 3 minutes at 100 ℃, apply 5 to the adhesive surface.
A 0 g / m ² piece of high-quality paper is attached and left in an atmosphere of 20 ° C and 65% RH for 24 hours to obtain a film for individual wrapping and a high-quality paper laminate, which is adhered to the silicone-coated surface of the laminate. The peel resistance (U peel) from the agent layer was measured at a tensile speed of 0.3 m / min.

[0039]

EFFECT OF THE INVENTION The individual wrapping film for sanitary napkins of the present invention has a tensile elastic modulus of 25 Kgf / mm ^{2 in} both longitudinal and transverse directions and a DSC measurement melting temperature of 130 ° C. or more, so that it is thin and flexible. However, it has excellent heat resistance, and can be processed with silicone without melting or significantly deforming.

Further, the thickness of the individual wrapping film for sanitary napkins of the present invention is set to 15 to 50 μm, and it is possible to secure a necessary strength and obtain a more flexible touch.

Furthermore, the wrapping film of the sanitary napkin of the present invention can be made invisible from the outside by setting the opacity to 40% or more.

Claims (3)

[Claims] 1. A polypropylene film, at least one side of which is treated with silicone, and the polypropylene film subjected to the silicone treatment has a tensile modulus of 25 Kgf / mm ² or less in both longitudinal and transverse directions and a melting temperature of 130 ° C. or higher measured by DSC. A film for an individual wrapping body of a sanitary napkin, which is characterized by: 2. The film for an individual package of a sanitary napkin according to claim 1, wherein the polypropylene film has a thickness of 15 to 50 μm. 3. A film for an individual package of a sanitary napkin according to claim 1, wherein the silicone-treated polypropylene film has a opacity of 40% or more by adding a pigment. .