JPS62148247A - Perforated resin film - Google Patents

Abstract

PURPOSE:To obtain a perforated resin film which does not make water permeate through despite the permeability to air, by making a hole diameter and the number of holes are set within specific ranges respectively. CONSTITUTION:A thermoplastic resin film is used as the base material and holes 2 whose diameters are 50-300mu are bored through the film at the rate of 50-300 piece per 1cm<2> so as to piece through both the surfaces of the film. Then resin of a wall forming the hole 2 forms a pleat 3 by fusing at the time of perforation. A perforated resin film 1 which does not permeate through water despite the permeability to air is obtained by so constituting the perforated film 1 that a quantity of permeation of water (JIS L-1079) at an hour measured under terms of 25 deg.C and 1kg/cm<2> is 0ml/cm<2>, permeability to water measured in conformity to JIB Z-0208 is more than 1,000g/m<2>.24hr.one atmospheric pressure and permeability to air measured by making use of an Ohken type permeability.smoothness testing machine manufactured in conformity to JIS Z IS P-8117 is less than 30sec.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is a film that allows gases such as nitrogen and oxygen to pass through, which is useful as a packaging film for fresh flowers and vegetables, and as a leak-proof material for sanitary napkins and disposable diapers. However, it relates to a perforated resin film that does not allow water to pass through.

[Prior art and 4 points in between] For packaging films for fresh flowers, fruits, etc., it is important to consider the balance between the competing performance requirements of prevention of moisture loss and breathability.
A resin film is used in which circular holes with a diameter of 4 to 5 mm are perforated at intervals of about 5 C7n, at the expense of preventing moisture from escaping.

However, since this perforated film has large pore diameters, moisture easily evaporates under conditions of a little over 100 lbs. or high temperatures, resulting in fresh flowers wilting and fruits becoming shriveled.

In addition, non-perforated arbor film is used as a leak-proofing material for disposable diapers and sanitary napkins, but this film has poor air permeability and swells easily.

[Specific measures to solve the problem]

The present invention provides a perforated resin film that has 1g leak-proof property and air permeability, and provides a perforated resin film that has air permeability but does not allow water to pass through by adjusting the pore diameter and number of holes.

In other words, 1 the present invention provides (a) a thermoplastic resin film as a material, and (b) a film in which pores having a diameter of 50 to 300 microns penetrate the front and back surfaces of the film at a rate of 50 to 300 per CfrL2. It is perforated (C
) The resin on the wall forming the holes melts in the bath during punching to form pleats, and (d) the punched film is heated at 25°C,
The permeation amount of water in 1 hour (JIS L-1079) measured under the condition of 1 kg/crn2 is 0 milliliter/c
(e) Moisture permeability measured in accordance with JIS Z-0208 is 1,000,97 m2/24 hours/
(f) JIS P-8117
A perforation that has air permeability but does not allow water to pass through, characterized by an air permeability of 30 seconds or less measured using the Oken style air permeability/smoothness test made in accordance with the above. The present invention provides a resin film.

[Thermoplastic resin film]

The film is made by melt-kneading thermoplastic resins such as polypropylene, polyethylene, polyamide, polyvinyl chloride, polyethylene, lenterephthalate, etc., or mixtures of these resins using an extruder, and then melt-kneading the mixture using an 'r-die, an inflation die, etc. It is obtained by extruding it into a film and cooling it. In the case of blown film, the cylindrical film is further cut open with a cutter to make it flat in order to facilitate perforation.

The thickness of the film is between 10 and 200 microns.

[Drilling]

The film is perforated using a hot needle or an electron beam.

It is preferable that the holes be arranged so that they have a regular pattern in appearance.

As a result of this perforation, the wall 3 of the hole 2 in the perforated portion of the film 1 is melted and cooled, forming folds 3 having a different melt orientation than the other film portion 1', as shown in FIG. The folds 3 improve the tear resistance of the film.

The pores 2 have a wide pore diameter t1 at the surface of the film 1 and a narrow pore diameter t2 at the center of the film, and this structure seems to be effective in preventing liquid leakage.

One surface of the perforated film is smooth and the other surface is rough, with part of the folds 3 of the holes 2 forming convex portions 4 projecting from the film surface.

The pore diameter t1 is 50 to 300 microns, and the number of pores is 50 to 300 microns.
300 i1m/cm'', so that the resulting perforated film has breathability and liquid leakage properties, i.e., at 25°C,
The permeation amount of water per hour measured under the condition of 1 kg/crn2 is 0 milliliter 2, and the moisture permeability is 1.00.
097m", 24 hours, 1 atm or more, air permeability 3
The hole diameter, number of holes, and hole spacing are selected to be less than 0 seconds.

It is difficult with current technology to obtain pores with a pore diameter of less than 50 microns, and it is difficult to provide a film with liquid leakage resistance when the pore diameter exceeds 300 microns. The number of holes is determined according to the hole diameter so as to satisfy the above-mentioned air permeability and water vapor permeability.

〔application〕

To package fresh flowers 5 and vegetables using the perforated resin film of the present invention, wrap them so that the rough side is on the inside and the smooth side is on the outside, and temporarily fasten with an adhesive tie f6f (see Figure 3). ).

Furthermore, when used as a liquid leakage prevention material for sanitary napkins and disposable diapers, the smooth side is used on the side in contact with the liquid absorbent body, and the sparse side is used on the outside of the liquid absorbent body.

The present invention will be explained below with reference to Examples.

Example 1 Mitsubishi Yukafuki polypropylene '°Noblen FB-3''
(trade name, melting point approximately 164°C) was melted and kneaded using extrusion @ sound, then extruded into a film at a temperature of 200°C using a goo, and cooled to approximately 30°C to obtain a film with a wall thickness of 60 microns. .

This film was perforated with a hole diameter of 200 microns and a number of holes of 100/crrL2 using a hot wire to obtain a perforated resin film having a cross-sectional structure shown in the perspective view of Fig. 1 and Fig. 2. One side of the film was smooth and the other side was a rough surface with protrusions 4 around the holes.

25℃, lkl of this perforated film? /crrL'', the permeation amount of water per hour is 0 milliliter/cfrL2, the moisture permeability is 12,000, and Si
'/m'' for 24 hours at 1 atm, and the air permeability was 2 seconds.

Examples 2-4. Comparative Example 1 A film having the physical properties shown in Table 1 was obtained in the same manner as in Example 1, except that the diameter and number of holes punched by a hot needle were changed as shown in Table 1.

Comparative Example 2 An unperforated film obtained in the same manner as in Example 1 was perforated with a hole diameter of 2 mm and a number of holes of 5/CrrL2 using a punch to obtain a perforated film.

There were no folds in the holes in this film, and both sides were smooth.

Table 1 shows the physical properties of this film.

Example 5 Polyethylene "° Yucalon YM-61" manufactured by Mitsubishi Yuka Co., Ltd.
” (Product name) 98 parts, manufactured by 5 Hara Sangyo Co., Ltd. Titanium dioxide 0
After melting and kneading a composition consisting of 2 parts of "Tie Bake CR-60" (trade name) using an extruder,
It was extruded into a film at a temperature of 30°C and cooled to about 30°C to obtain a white, opaque film with a wall thickness of 20 microns.

This film 1 &: Perforated in the same manner as in Example 1.

The hole diameter of this perforated film is 200 microns, and the number of holes is 10.
One surface was smooth and the other surface was rough with convex portions around the holes.

The amount of water that permeates through this perforated film in 1 hour measured at 25°C and 1 U/cr IL20 is 0 ml/c.
1rL2, moisture permeability is 10,000. ! i'/m2
- 24 hours, 1 atm, air permeability was 3 seconds.

Application Example 1 Using the perforated film obtained in Example 1, fresh flowers that had been sufficiently watered and sprayed with a mist were packaged in the form shown in FIG. 3.

The packaged flowers were left in a constant temperature room at 25° C. and humidity 30 S RH for 3 days.

The same thing was done with the films of Comparative Examples 1 and 2.

Table 2 shows the changes in appearance of these films and flowers.

Table 2 Application Example 2 The perforated film obtained in Example 5 was wrapped in a single layer around the arm with a width of 50 strips, assuming that it would be used as a base material for a patch.

After 2 hours, the bowl was immersed in warm water at 40°C for 10 minutes.
I wiped the water off with a towel.

After another 50 minutes, the film was unwound and the arm was observed. The same thing was done with the film of Example 5 before perforation.

When the film before perforation was used, the arm had a slight white color, but when the film of Example 5 was used, the reddish color was slightly lighter.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a perforated resin film, FIG. 2 is a partial sectional view of the perforated film of the present invention, and the third factor is a diagram of fresh flowers packaged using the perforated film of the present invention. In the figure, 1 is a perforated film, 2 is a hole, 2' is a hole diameter, 3 is a pleat, 4 is a convex portion made of residual resin from the perforation, 5 is a flower, and 6 is an adhesive tape for sealing. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1) (a) A thermoplastic resin film is used as the material, (b) This film has 1 cm pores with a pore diameter of 50 to 300 microns.
There are 50 to 300 perforations per ^2 that penetrate the front and back surfaces of the film, (c) the resin on the wall that forms these holes melts during the perforation to form pleats, and (d) this The perforated film has a water permeation rate of 1 hour (JIS L-1) measured at 25°C and 1 kg/cm^2.
079) is 0 ml/cm^2, and (e) J
Moisture permeability measured according to IS Z-0208 is 1.0
00g/m^2, 24 hours, 1 atm or more, (f)
It has air permeability, characterized by an air permeability of 30 seconds or less as measured using an Oken air permeability/smoothness tester made in accordance with JIS P-8117, but does not allow water to pass through. Perforated resin film. 2) The perforated resin film according to claim 1, wherein one surface of the film is smooth and the other surface is rough. 3) The perforated resin film according to claim 1, wherein the film has a wall thickness of 10 to 200 microns.