JP3167091B2 - Polyolefin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyolefin film.

[0002]

2. Description of the Related Art Heat-sealing polyolefin films are used for packaging foods and the like.

[0003] When packaging a food having a high water content such as diaper or the like with such a polyolefin film, moisture penetrates into the gaps of the portions where the wrapping pieces of the polyolefin film overlap with each other, and both wrapping pieces are formed. Easy to adhere exactly. As a result, in such a package, when the package is opened, there is an unnecessarily strong resistance to peeling off the attached wrapping pieces, and in some cases, an unreasonable force is applied to the packaged item such as the onigiri. This causes the article to crack. Therefore, a high slip property is required for a polyolefin film for packaging a food having a high moisture content.

In the packaging of foods such as diapers, when the contact point between the article and the film is seen through as wet, or when water droplets generated by water vapor generated from the article are seen through, the appearance of the product is emphasized. In this case, there is a problem that the commercial value is reduced. Therefore, such a polyolefin film is required to have an appropriate degree of opacity such that the inside cannot be seen through the package.

[0005] Under the above background, the present inventors have proposed a heat-sealable polyolefin film having excellent slipperiness and moderate opacity as a 90% by weight of polypropylene.
And a base layer of a mixture of about 70% by weight and 10% to 30% by weight of high density polyethylene, and an average particle diameter of 0.5 to 3 μm.
m, a polyolefin film comprising a base layer containing a silicone rubber particle having a rubber hardness A of 30 to 80 of 0.05 to 1% by weight and a surface layer of a polyolefin having a lower melting point than the above-mentioned base layer has been proposed (Japanese Patent Application Laid-open No. No. 9638).

[0006]

This polyolefin film is good as a packaging film for diapers and the like. Particularly, when a lubricant such as higher fatty acid amides is further used in the surface layer thereof, its slip property is high. Can be further improved, and an extremely excellent packaging film can be obtained.

[0007] However, since the lubricant generally requires a certain curing period before it oozes out on the film surface after the film is produced, the effect of improving the slipperiness is hardly exhibited immediately after the film is produced. Therefore, in the above-mentioned polyolefin film, the slip property immediately after production is usually
It is difficult to greatly improve the effect of the silicone rubber particles blended in the surface layer. Thus, the polyolefin film, immediately after this production,
The slipperiness exhibited by the silicone rubber particles is not one step satisfactory at this time, and wrinkles occur in the film winding process, or a part of a thick winding state occurs because the film cannot be uniformly wound, and one time In the winding process, troubles such as thick winding could occur.

In view of the above background, the present invention relates to a heat-sealing polyolefin film having high slipperiness and moderate opacity and capable of satisfactorily packaging the food having a high moisture content. Improve slipperiness,
It is an object of the present invention to provide a polyolefin film in which troubles in a film winding step immediately after production are well suppressed.

[0009]

Means for Solving the Problems The present inventors have intensively studied to solve the above problems. As a result, they have found that the above problems can be solved by using specific crosslinked (meth) acrylic resin particles as particles to be contained in the film surface layer, and have completed the present invention.

That is, the present invention relates to 90% to 70% by weight of polypropylene and 10% to 30% by weight of high density polyethylene.
And a mean particle diameter of 0.4 to 7 μm.
m (crosslinked (meth) acrylic resin particles)
A polyolefin film for food packaging having a high moisture content, wherein a polyolefin surface layer having a lower melting point than a mixture of the above-mentioned polypropylene and high-density polyethylene containing 10% by weight is laminated.

[0011] In the polyolefin film of the present invention, the layer serving as the base layer comprises 90 to 70% by weight of polypropylene.
It is preferably formed from a mixture of 90 to 75% by weight of polypropylene and 10 to 30% by weight, preferably 10 to 25% by weight of high density polyethylene. Polypropylene films are generally transparent and the slipperiness between the films is not sufficient, but when a mixture of such polypropylene and the above amount of high-density polyethylene is used as the base layer of the film, The surface of the film is roughened so that the slipperiness between the films is improved, and the film has an appropriate degree of opacity such that the inside cannot be seen through when it is made into a packaging film. Here, as the polypropylene which is a component of the mixture, a known polypropylene can be used without any particular limitation. Specifically, in addition to a propylene homopolymer, a copolymer of propylene with another copolymerizable monomer such as an ethylene-propylene copolymer, a propylene-butene copolymer, and an ethylene-propylene-butene copolymer. It may be united. In the present invention, polypropylene has a melt flow index (hereinafter, abbreviated as MFI) = 0.5 to 1
0 g / 10 min (230 ° C.) and 1.0 to 5.0
g / 10 min (230 ° C.).

On the other hand, known high-density polyethylene can be used without any particular limitation. Specifically, the density is 0.945 g / cm ³ or more, preferably 0.945 to
At 0.960 g / cm ³ , MFI = 0.05 to 2.0 g
/ 10 min (190 ° C.) is preferred for imparting opacity to the film.

When the amount of the high-density polyethylene is less than 10% by weight in the above-mentioned mixture of polypropylene and high-density polyethylene, roughening of the film surface becomes insufficient, the slipperiness between the films is reduced, and the opacity of the film is reduced. Run out. On the other hand, when the amount of the high-density polyethylene is more than 30% by weight, the film forming property of the film is reduced.

Next, in the polyolefin film of the present invention, the base layer contains 0.05 to 1% by weight of crosslinked (meth) acrylic resin particles having an average particle diameter of 0.4 to 7 μm. A surface layer made of a polyolefin having a lower melting point than the mixture of the polypropylene and the high-density polyethylene, which is the material, is laminated. Therefore, the polyolefin film of the present invention can be subjected to heat sealing only the surface layer by applying heat lower than the melting point of the mixture forming the base layer and higher than the melting point of the polyolefin forming the surface layer. .

The low-melting-point polyolefin described in the present invention refers to a polyolefin that melts at a lower temperature than a mixture of polypropylene and high-density polyethylene, even if it does not necessarily show a clear peak in thermal analysis. Good.

In addition, since the surface of the base layer film is roughened, the surface of the film on which the surface layer is formed is similarly roughened due to the unevenness of the base layer film. In the polyolefin film of the present invention, such a surface layer contains crosslinked (meth) acrylic resin particles having a specific particle size that imparts good slip properties to the film as described above. In a polyolefin film, the crosslinked (meth) acrylic resin particles and the unevenness of the film surface act synergistically to significantly improve the slipperiness. In addition, such a surface layer may be formed on only one surface of the base layer, but is preferably formed on both surfaces of the base layer in consideration of operability at the time of packaging.

In the present invention, the crosslinked (meth) acrylic resin particles contained in the surface layer have an average particle diameter of 0.4 to 0.4.
It is 7 μm, preferably 1 to 5 μm. When the average particle size of the crosslinked (meth) acrylic resin particles is less than 0.4 μm,
When the effect of improving the slipperiness is poor, and when it exceeds 7 μm, on the contrary, not only is the appearance of the film unfavorable due to the generation of fish eyes centered on the spherical particles, but also the falling of the fine particles increases, and the packaging machine and the post-process There is a risk of contaminating the transport device and the package itself.

The crosslinked (meth) acrylic resin particles of the present invention are particles formed by crosslinking a unit containing a unit based on an acrylic monomer or a methacrylic monomer as a main component.
Known ones can be used without any limitation. Taking into account the good physical properties such as slipperiness and scratch resistance of the obtained film, the unit based on the (meth) acrylic monomer is 50 to 50.
100% by weight, preferably 70-100% by weight, while
Those containing units based on a crosslinking agent or another monomer copolymerizable with the (meth) acrylic monomer are preferably 0 to 50% by weight, more preferably 0 to 30% by weight.

The (meth) acrylic monomer is not particularly limited, but may be, for example, acrylic acid such as acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, or the like. Methacrylic acid or methacrylic acid ester derivatives such as acrylate derivatives, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, etc. No. Among them, it is more preferable to use a lower alkyl ester of acrylic acid or methacrylic acid such as methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate as a main component. These (meth) acrylic monomers may be used alone or in combination of two or more. Further, a metal salt of acrylic acid or methacrylic acid, an amide derivative, or an ester derivative having a special structure such as hydroxyethyl ester or dimethylaminoethyl ester may be used.

In order to provide a crosslinked structure, a (meth) acrylic monomer having two or more polymerizable double bond groups in the molecule may be copolymerized with the above (meth) acrylic monomer. Examples of such crosslinkable (meth) acrylic monomers include trimethylolpropane triacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, decaethylene glycol dimethacrylate, pentacontaector ethylene glycol dimethacrylate, 1,3-butylene dimethacrylate,
Allyl methacrylate, tilimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate,
Examples thereof include diethylene glycol dimethacrylate and diethylene glycol phthalate, and a plurality of these can be used in combination.

In addition, aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene and derivatives thereof, N, N-divinylaniline, divinyl ether, divinyl sulfide, etc., as long as the mixing ratio of the (meth) acrylic monomer is not impaired. It is also possible to use a crosslinking agent such as divinyl sulfonic acid to impart a crosslinked structure.

On the other hand, the (meta) used in the present invention
As the other monomer copolymerizable with the acrylic monomer, a known monomer is used without any particular limitation, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-
Styrene-based monomers such as phenylstyrene, o-chlorostyrene, m-chlorostyrene, and p-chlorostyrene;
Examples include ethylene, propylene, butylene, vinyl chloride, vinylidene chloride, vinyl acetate, acrylonitrile, methacrylonitrile, acrylamide, and N-vinylpyrrolidone.

The fact that the (meth) acrylic resin is particularly cross-linked means that when mixed with the polyolefin resin used for the film surface layer and melt-kneaded, the polyolefin resin retains the particle shape in the polyolefin resin. Essential for dispersal. The shape of the crosslinked (meth) acrylic resin particles is not particularly limited, but is preferably spherical in consideration of improvement in slipperiness.

In the polyolefin film of the present invention, the content of the crosslinked (meth) acrylic resin particles contained in the surface layer is 0.05 to 1% by weight, and 0.1 to 0.8% by weight. It is preferred that When the blending amount of the crosslinked (meth) acrylic resin particles is less than 0.05% by weight, the effect of improving the slipperiness is poor, and the blending amount is 1% by weight.
Even if it is added in excess of the above, improvement in the effect of improving the slipperiness cannot be expected.

In the polyolefin film of the present invention, the polyolefin having a lower melting point than the mixture of the polypropylene and the high-density polyethylene forming the base layer, which is the material resin of the surface layer, is not particularly limited. Preferably, the melting point is 10 to 80 ° C. lower than the melting point of the mixture of the base layer. If these polyolefins are specifically shown, ethylene, propylene, 1-
Α-olefin homopolymer such as butene, a copolymer of the α-olefins, a copolymer of a monomer other than the α-olefin and an α-olefin copolymerizable with the α-olefin, and These mixtures and the like are employed without any limitation. Examples of the monomer other than the α-olefin copolymerizable with the α-olefin include vinyl acetate and maleic acid. In the present invention, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-1-butene copolymer, ethylene-propylene-1-butene copolymer, ethylene-propylene-butadiene copolymer It is most preferable to use a blend containing these polyolefins as a main component.

In the polyolefin film of the present invention, the thickness of the base layer is not particularly limited, but is generally in the range of 10 to 100 μm, preferably 15 to 50 μm. The thickness of the surface layer laminated on the surface of the base layer is not particularly limited,
It imparts sufficient heat-sealing properties to the film, prevents the loss of crosslinked (meth) acrylic resin particles due to friction between the films, and sufficiently generates irregularities due to the irregularities on the surface of the base layer film. In order to improve the slipperiness, 0.5 to 5.0 μm, preferably 0.5 to 3.0 μm.
It is preferable to set the range to 0 μm.

In the polyolefin film of the present invention, the base layer formed of a mixture of polypropylene and high-density polyethylene has molecules oriented in a uniaxial direction or in a uniaxial direction and a direction substantially perpendicular to the uniaxial direction by stretching. Is preferred. In this case, the stretching ratio is generally preferably 1.1 to 8 times in the case of uniaxial stretching, and 3 to 12 times in the direction perpendicular to the direction of uniaxial stretching in the case of biaxial stretching. Similarly, in the surface layer laminated on the base layer, molecules may be oriented in the uniaxial direction, or in the uniaxial direction and a direction substantially perpendicular to the uniaxial direction.

[0028] The polyolefin film of the present invention may be produced by any method. Generally, it can be manufactured by the following method. First, a mixture of polypropylene and high-density polyethylene to be a base layer is extruded into a sheet, which is stretched in a uniaxial direction 1.1 to 8 times to obtain a uniaxially stretched sheet. Next, in order to form a surface layer, containing crosslinked (meth) acrylic resin particles,
A polyolefin having a lower melting point than the base layer is extruded into a sheet, and this is laminated on the uniaxially stretched sheet. Alternatively, the polyolefin film of the present invention can be obtained by further stretching the laminated sheet 3 to 12 times in a direction substantially perpendicular to the uniaxial stretching direction. The base layer and the surface layer can be simultaneously extruded and laminated, and this can be uniaxially or biaxially stretched by the same method as described above.

In the base layer and the surface layer of the polyolefin film of the present invention, various additives usually known to be added to a plastic film, for example, a heat stabilizer, an antioxidant, a crystal nucleating agent, an antistatic agent , A lubricant, an antiblocking agent, an antibacterial agent, a freshness preserving agent and the like may be added. Among them, use of a lubricant in the surface layer is preferred for improving the slipperiness of the film. Examples of the lubricant include higher fatty acid amides such as erucamide, oleamide, stearamide, ethylenebisstearamide, N-amide
Stearyl erucamide and the like can be preferably used. Usually, it is preferable that such a lubricant contains erucamide or oleamide.

The polyolefin film of the present invention is not particularly limited, but can be used as a packaging material for various articles. Considering that the films are extremely slippery and have an appropriate degree of opacity such that the inside cannot be seen through, it is preferable to use the film as a food film having a high water content, particularly, a packaging film for diaper.

FIG. 2 shows an example in which the polyolefin film of the present invention is used as an inner wrapping film for diapers which is eaten by winding with nori.

FIG. 1 is a cross-sectional view of a case where the polyolefin film of the present invention is used as an inner wrapping film and edible diapers are wrapped around nori and edible. In FIG. 1, the diaper 1 is composed of two inner wrapping films 2a and 2b composed of the polyolefin film of the present invention.
Its surface is covered and packaged. And the above 2
In the two inner wrapping films a and 2b, at least one (2a) edge portion on the diaper has a folded structure inside, and most of the diaper surface is in contact with the folded piece 3. . In FIG. 2, reference numeral 4 denotes an outer wrapping film having a rupture portion 5 at a predetermined location. The outer wrapping film and the inner wrapping film are bonded and fixed at predetermined locations at respective edges by heat sealing. A laver 6 is stored between the outer film and the inner wrapping films 2a and 2b. In such a diaper package, the rupture portion 5 of the outer packaging film is torn when edible,
By pulling both the interior and exterior packaging films together in the opposite directions of A and B and removing them from the diaper, a nori-wrapped diaper is easily made. At this time, in the folded piece 3 of the inner wrapping film 2a, the film does not slide on the diaper in the above-described pulling direction (A direction), but is peeled off from the diaper. Accordingly, the folded piece 3 can be easily peeled off from the surface of the diaper 3 even though the diaper having a highly adhesive surface is packaged.

On the other hand, the folded piece 3 is in close contact with the surface of the inner wrapping film 2a facing the folded piece in a wet state with the moisture of the diaper 1. However, since the inner wrapping film 2a is made of the polyolefin film of the present invention having good slipperiness between the films as described above, the folded piece 3 can easily be formed when the film is taken out. Slide on the opposing surface of the. As a result, in such a diaper package, the inner wrapping film can be easily pulled from the diaper with a small resistance.

Further, in such a diaper package, even when a highly transparent film is used as the outer wrapping film 4, the inner wrapping film 2a, 2b has an appropriate opacity, so that the inner diaper is not formed. Not seen through,
The diaper looks wet and does not impair its appearance.

[0035]

As described above, the polyolefin film of the present invention is not only excellent in the scratch resistance of the film and the heat sealing property, but also the sliding property between the films is further improved, so that it is extremely good. Therefore, for example, when the diaper is packaged, the diaper can be taken out very smoothly when the package is opened, and the diaper may be cracked due to excessive force applied to the diaper at the time of opening. Absent. In addition, it is excellent in bag-making workability at the time of laver packaging, etc., and is unlikely to cause poor film folding. Moreover, since the inside has an appropriate degree of opacity such that the inside cannot be seen through, the diaper is not seen through the wet feeling when the diaper or the like is packaged, and the commercial value of the diaper is not reduced. Further, it can be used for packaging by an automatic packaging machine by utilizing its heat sealing property.

In the polyolefin film of the present invention, troubles in winding the film hardly occur even during the production thereof, particularly due to the further improvement of the slipperiness of the film, and the quality control is difficult. Are also very preferred.

[0037]

EXAMPLES The present invention will be described below in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In addition, the measurement of the film physical properties in the following Examples and Comparative Examples was performed by the following methods.

(1) Haze The haze was measured according to JIS K6714.

(2) Scratch resistance Two films cut into a size of 20 cm × 30 cm were overlapped, one was fixed below, and one was set above. Put a 4.6kg weight on the upper film and lower film and 10c
The contact was performed in an area of mx 10 cm, and the upper film was horizontally moved to rub two times between 20 cm. The haze was measured before and after the operation, and the difference was 0% or more to less than 3%, ○: 3% or more to less than 10%, and X: 10% or more.

(3) Slipperiness I After forming the film, ASTM-D-1 was used at room temperature within 30 minutes.
It was measured in accordance with the 894 dynamic friction coefficient measuring method.

(4) Slippery II After film formation, after curing at 40 ° C. for 3 days, ASTM-D
It measured according to the dynamic friction coefficient measuring method of -1894.

(5) Heat Sealability A heat seal bar of 5 × 200 mm was used, and at each set temperature, a heat seal pressure of 1 kg / cm ² and a heat seal time of 1.0 second from a sample sealed at a temperature of 1.0 second.
A sample having a width of m was cut out and measured at a tensile speed of 100 mm / min using a tensile tester. The results were average values of five samples.

(6) Opening property of diaper A 20-μm-thick double-sided heat-sealable polypropylene biaxially stretched film having a thickness of 20 μm was used as the outer packaging film. In addition,
This outer wrapping film is provided with a 3 mm wide opening tape portion coated with a hot melt agent as a break portion at the time of opening. Each test film was used as an inner wrapping film, and a diaper wrapping film having a structure as shown in FIG. 2 was prepared using an impulse sealing machine and a simple iron. A commercially available diaper was wrapped with the diaper packaging film as shown in FIG. The diaper was actually opened and the openability of the diaper was evaluated. Each test film was evaluated with ten diapers, and a five-point evaluation was performed based on whether or not the diaper was broken at the time of opening.

5 points: 0 broken diapers 4 points: 〃 1 to 2 3 points: 〃 3 to 4 2 points: ５ 5 to 6 1 point: ７ 7 to 10 (7 ) Permeability of diaper Each test film was applied to a commercially available diaper surface, and it was observed whether the surface of the diaper could be seen through the film. When the film was opaque and the diaper could not be seen through, it was evaluated as ○.

The crosslinked (meth) acrylic resin particles used in the present invention are as follows.

Crosslinked methacrylic resin particles A: average particle diameter 2.0 μm “Tocello γ agent, γ-4” manufactured by Tokyo Cellophane Paper Co., Ltd. Crosslinked methacrylic resin particles B: average particle diameter 1-2 μm “MP -1400 "(manufactured by Soken Chemical Co., Ltd.)-Crosslinked methacrylic resin particle particles C: average particle diameter 2.0 μm" Eposter MA1002 "(manufactured by Nippon Shokubai Co., Ltd.)-Crosslinked methacrylic resin particle particles D: average particle diameter 4.0 μm" Eposter MA1004 " "Nippon Shokubai Co., Ltd.-Crosslinked acrylic resin particle particles E: those produced by the following method were used.

In a flask equipped with a stirrer, an inert gas inlet tube, a reflux condenser and a thermometer, a polyoxyethylene alkyl sulfonammonium (“HYTENOL N-0”) was added.
8 ", manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and 900 parts of deionized water in which 0.5 part was dissolved was charged. A mixture prepared in advance by mixing 70 parts of butyl acrylate, 30 parts of styrene, 1 part of azoisobutyronitrile and 5 parts of P-nitrobenzoic acid was added thereto. K. The mixture was stirred at 8000 rpm for 5 minutes with a homogenizer (manufactured by Tokushu Kika Kogyo Co., Ltd.) to form a uniform suspension. Next, the mixture was heated to 75 ° C. while blowing nitrogen gas, stirred at this temperature for 5 hours to carry out a suspension polymerization reaction, and then cooled. The suspension was filtered and dried to obtain crosslinked acrylic resin particles. At this time, non-volatile components (emulsion polymerized fine particles) contained in the filtrate were 1.3%.
It was 5 kg. As a result of measuring the obtained crosslinked acrylic resin particles with a Coulter counter, the average particle size was 4.1.
μm.

Examples 1-3 Melt Flow Index at 230 ° C. = 2.0 g
A mixture of 80% by weight of polypropylene / 10% and 20% by weight of a high-density polyethylene having a melt flow index at 190 ° C. of 1.0 g / 10 minutes and a density of 0.955 g / cm ³ was 240 wt. The resin was extruded into a sheet at a resin temperature of 0 ° C., and cooled and solidified by a chill roll maintained at 60 ° C. to form a 1.1 mm thick sheet.

Then, a melt flow index at 230 ° C. = 8.0 g / 10 min, 79.3% by weight of an ethylene-propylene copolymer, 20% by weight of a propylene-butene copolymer, and a crosslinked (meth) compound shown in Table 1. A mixture of 0.2% by weight of acrylic resin particles and 0.5% by weight of erucamide was extruded at 230 ° C. by an extruder and pelletized to obtain a polyolefin resin composition. The melting point (main peak in differential scanning calorimetry) of the resin component composed of a mixture of the ethylene-propylene copolymer and the propylene-butene copolymer was 136 ° C., which was 14 ° C. lower than the melting point of the resin component of the base layer. ° C was low.

Next, the above-mentioned sheet was stretched 4.8 times at 150 ° C. by a hot roll stretching machine to obtain a 230 μm uniaxially stretched sheet. The above polyolefin-based resin composition was extruded into a sheet at a resin temperature of 230 ° C. using a T-die extruder, and laminated on a uniaxially stretched sheet and a roll maintained at 70 ° C. to obtain a 240 μm two-layer sheet.

Further, the polyolefin resin composition was similarly laminated on the uniaxially stretched sheet surface side of the two-layer sheet to obtain a 250-μm three-layer sheet.

Subsequently, the three-layer sheet was stretched 10-fold at 160 ° C. using a transverse stretching machine, and the base layer comprising a mixture of polypropylene and high-density polyethylene was 23.0.
A polyolefin film having a thickness of 1.0 μm and a surface layer composed of the polyolefin resin composition of 1.0 μm and a total thickness of 25.0 μm was obtained. For the obtained polyolefin film, measure haze, scratch resistance, slipperiness, heat sealing property, openability of diaper, and transparency of diaper,
The results are shown in Table 2.

Examples 4 to 10 In Example 3, the types and contents of the crosslinked (meth) acrylic resin particles to be contained in the surface layer, the thicknesses of the base layer and the surface layer, and the resin composition of the base layer are shown in Table 1. Except having changed, it carried out similarly to Example 3, and obtained the polyolefin film. The resulting polyolefin film was measured for haze, scratch resistance, slip property, heat sealing property, diaper opening property, and diaper transparency, and the results are shown in Table 2.

Comparative Examples 1 to 3 In Examples 1, 4 and 5, except that the particles contained in the surface layer were changed to silicone rubber spherical particles having an average particle diameter of 2 μm and a rubber hardness A = 40 degrees. 1, 4, 5
A polyolefin film was obtained in the same manner as described above. The rubber hardness A was measured according to JIS K6301. The resulting polyolefin film was measured for haze, scratch resistance, slip property, heat sealing property, diaper opening property, and diaper transparency, and the results are shown in Table 2.

Comparative Example 4 Melt Flow Index at 230 ° C. = 2.0 g
/ 10 minutes of polypropylene was converted to 24 using a T-die extruder.
A polyolefin film was obtained in the same manner as in Example 3, except that a base layer was formed by extruding a sheet at a resin temperature of 0 ° C. Haze about the obtained polyolefin film,
The scratch resistance, slipperiness, heat sealability, diaper opening property, and diaper transparency were measured, and the results are shown in Table 1.

Comparative Examples 5 and 6 In Example 1, the particles contained in the surface layer were pulverized silica particles having an average particle diameter of 1.8 μm, and an average particle diameter of 2.0 μm.
A polyolefin film was obtained in the same manner as in Example 1, except that the particles were changed to non-melting type silicone resin spherical particles of μm. Haze about the obtained polyolefin film,
The scratch resistance, slipperiness, heat sealability, diaper opening property, and diaper transparency were measured, and the results are shown in Table 2.

[0057]

[Table 1]

[0058]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a case where edible rice wrapped around nori is wrapped using the polyolefin film of the present invention as an inner wrapping film.

[Explanation of symbols]

 1: rice ball 2a, 2b: inner wrapping film 3: folded piece 4: outer wrapping film 5: broken part 6: laver

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-9638 (JP, A) JP-A 7-17000 (JP, A) JP-A-7-40518 (JP, A) JP-A 3- 213339 (JP, A) JP-A-7-52338 (JP, A) JP-A-63-19253 (JP, A) JP-A-6-212404 (JP, A) JP-A-63-19252 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (1)

(57) [Claims] 1. A base layer comprising a mixture of 90% by weight to 70% by weight of polypropylene and 10% by weight to 30% by weight of a high-density polyethylene, and crosslinked (meth) acrylic resin particles having an average particle diameter of 0.4 to 7 μm. Water formed by laminating a surface layer of a polyolefin having a lower melting point than a mixture of the above polypropylene and high density polyethylene containing 0.05 to 1% by weight.
High content polyolefin film for food packaging .