JPH08252893A - Polyolefin film - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a heat-sealable polyolefin film having high slipperiness and appropriate opacity and capable of favorably packaging a food having a high water content. It is an object of the present invention to provide a polyolefin film which has improved properties and has successfully suppressed troubles and the like in the film winding step immediately after production. [Structure] Polypropylene 90% to 70% by weight, preferably 90% to 75% by weight and high density polyethylene 10
% By weight to 30% by weight, preferably 10% by weight to 25% by weight
And a surface layer of a polyolefin having a melting point lower than that of the base layer containing 0.05 to 1% by weight of crosslinked (meth) acrylic resin particles having an average particle size of 0.4 to 7 μm. the film.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polyolefin film.

[0002]

2. Description of the Related Art A heat-sealing polyolefin film is used for packaging foods and the like.

[0003] By the way, when such a polyolefin film is used to package foods having a high water content such as diaper, water penetrates into the gaps between the wrapping pieces of the polyolefin film, so that both wrapping pieces are separated from each other. Easy to attach. As a result, in such a package, when the package is opened, a feeling of unnecessarily strong resistance to peeling off both of the above-mentioned package pieces attached is generated, and in some cases, an unreasonable force is exerted on the packaged items such as rice balls. This causes the article to crack. Therefore, the polyolefin film for packaging such a food having a high water content is required to have high slipperiness.

Further, in the packaging of such foods as rice balls, the appearance is emphasized when the contact portion between the article and the film is seen through as if it is wet or the water droplets generated by the water vapor are seen through the article. In, there arises a problem of reducing the commercial value. Therefore, such a polyolefin film is required to have appropriate opacity so that the inside cannot be seen through when it is packaged.

Against the above background, the present inventors have found that 90% by weight of polypropylene is used as a heat-sealable polyolefin film having excellent slipperiness and appropriate opacity.
-70 wt% and high-density polyethylene 10 wt% -30 wt% mixture base layer, average particle size 0.5-3μ
m, and a polyolefin film in which a surface layer of a polyolefin having a lower melting point than the above base layer containing 0.05 to 1% by weight of silicone rubber particles having a rubber hardness A of 30 to 80 is laminated (JP-A-7- 9638).

[0006]

This polyolefin film is excellent as a packaging film for the above-mentioned rice balls, etc., and in particular, when a lubricant such as higher fatty acid amides is also used in the surface layer thereof, its slipperiness is improved. Can be further improved, and an extremely excellent packaging film can be obtained.

However, in general, a lubricant requires a certain curing period before leaching on the surface of the film after the film is manufactured, so that the effect of improving the slipperiness is hardly exhibited immediately after the film is manufactured. Therefore, in the polyolefin film, the slipperiness immediately after production is usually
It is difficult to further improve the effect beyond the effect of the silicone rubber particles blended in the surface layer. Then, the polyolefin film, immediately after this production,
The slipperiness exhibited by the silicone rubber particles is not satisfactory yet, and wrinkles are generated in the film winding process, or a part in a thick winding state is generated because the film cannot be wound evenly. Occasionally, troubles such as being unable to be thickly wound occurred in the winding process.

Against the above background, the present invention provides a heat-sealable polyolefin film which has high slipperiness and appropriate opacity, and which can satisfactorily package the food having a high water content. Improves slipperiness,
An object of the present invention is to provide a polyolefin film in which troubles and the like in the film winding step immediately after production are well suppressed.

[0009]

[Means for Solving the Problems] The present inventors have conducted extensive studies 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, according to the present invention, 90% by weight to 70% by weight of polypropylene and 10% by weight to 30% by weight of high density polyethylene.
Base layer of mixture with wt%, average particle size 0.4 ~ 7μ
The crosslinked (meth) acrylic resin particles of m are 0.05 to 1
It is a polyolefin film obtained by laminating a surface layer of a polyolefin having a melting point lower than that of a mixture of the above-mentioned polypropylene contained by weight% and high-density polyethylene.

In the polyolefin film of the present invention, the base layer is polypropylene 90 to 70% by weight.
It is preferably formed from a mixture of 90 to 75% by weight polypropylene and 10 to 30% by weight high density polyethylene, preferably 10 to 25% by weight. A polypropylene film is generally transparent and is not sufficiently slippery between the films, but when a mixture of such polypropylene and the above-mentioned 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 appropriate opacity so that the inside cannot be seen through when it is used as a packaging film. Here, the polypropylene that is a component of the mixture is not particularly limited, and known ones can be used. Specifically, other than propylene homopolymer, copolymerization of propylene with other copolymerizable monomers such as ethylene-propylene copolymer, propylene-butene copolymer, ethylene-propylene-butene copolymer, etc. It may be a united body. In the present invention, polypropylene has a melt flow index (hereinafter abbreviated as MFI) = 0.5 to 1
0g / 10min (230 ° C) and 1.0 to 5.0
It is preferably g / 10 min (230 ° C.).

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

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

Next, in the polyolefin film of the present invention, the above base layer contains 0.05 to 1% by weight of crosslinked (meth) acrylic resin particles having an average particle size of 0.4 to 7 μm, and the base layer. A surface layer made of a polyolefin having a melting point lower than that of the mixture of the polypropylene and the high-density polyethylene, which are the materials described above, 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 is a polyolefin that melts at a lower temperature than that of a mixture of polypropylene and high-density polyethylene, even if it does not always show a clear peak in thermal analysis. Good.

Further, since the surface of the base layer film is roughened, the surface of the film forming the surface layer is also roughened in accordance with the unevenness of the base layer film. Thus, the surface layer of the polyolefin film of the present invention contains crosslinked (meth) acrylic resin particles having a specific particle diameter that imparts good slipperiness to the film, as described above. In the polyolefin film, the crosslinked (meth) acrylic resin particles and the unevenness of the film surface act synergistically to remarkably improve the slipperiness. Note that such a surface layer may be formed on only one surface of the base layer, but it is preferably formed on both surfaces of the base layer in consideration of operability during packaging.

In the present invention, the crosslinked (meth) acrylic resin particles contained in the surface layer have an average particle size of 0.4 to
7 μm, preferably 1 to 5 μm. When the average particle diameter of the crosslinked (meth) acrylic resin particles is less than 0.4 μm,
If the slipperiness improving effect is poor and conversely exceeds 7 μm, not only the appearance of the film is unfavorable due to the generation of fish eyes centering on spherical particles, but also the fine particles drop out, which causes There is a risk of contaminating the carrier and the packaging itself.

The crosslinked (meth) acrylic resin particles of the present invention are particles which are crosslinked with a unit based on an acrylic monomer or a methacrylic monomer as a main component and are crosslinked.
Known materials can be used without any limitation. Considering 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 0 to 50% by weight, preferably 0 to 30% by weight, of a unit based on a crosslinking agent or another monomer copolymerizable with the (meth) acrylic monomer are suitable.

The (meth) acrylic monomer is not particularly limited, but for example, acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, dodecyl acrylate, or other acrylic acid or Acrylic acid ester derivatives, methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, and other methacrylic acid or methacrylic acid ester derivatives are available. Can be mentioned. Among these, it is more preferable that the main component is a lower alkyl ester of acrylic acid or methacrylic acid such as methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate. 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, an ester derivative having a special structure such as hydroxyethyl ester or dimethylaminoethyl ester may be used.

In order to impart a crosslinked structure, a (meth) acrylic monomer having two or more polymerizable double bond groups in the molecule may be copolymerized with the (meth) acrylic monomer. Examples of such crosslinkable (meth) acrylic monomers include trimethylolpropane triacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, decaethylene glycol dimethacrylate, pentacontahector ethylene glycol dimethacrylate, 1,3-butylene dimethacrylate,
Allyl methacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate,
Examples thereof include diethylene glycol dimethacrylate phthalate and the like, and it is possible to use a plurality of them in combination.

Aromatic divinyl compounds such as divinylbenzene, divinylnaphthalene, and their derivatives, N, N-divinylaniline, divinyl ether, divinyl sulfide, etc., within a range that does not hinder the blending ratio of the (meth) acrylic monomer. It is also possible to impart a crosslinked structure by using a crosslinking agent such as divinyl sulfonic acid.

On the other hand, used in the present invention (meta)
As the other monomer copolymerizable with the acrylic monomer, known monomers can be used without particular limitation, and examples thereof include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-methoxystyrene, p-tert-butylstyrene, p-
Styrenic monomers such as phenylstyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, etc.
Examples thereof include ethylene, propylene, butylene, vinyl chloride, vinylidene chloride, vinyl acetate, acrylonitrile, methacrylonitrile, acrylamide, and N-vinylpyrrolidone.

It should be noted that the fact that the (meth) acrylic resin is particularly crosslinked means that the polyolefin resin used in the film surface layer is mixed with the polyolefin resin and melt-kneaded in the polyolefin resin while maintaining the shape of the particles. It is essential for dispersion. The shape of the crosslinked (meth) acrylic resin particles is not particularly limited, but it is preferably spherical in consideration of improvement of 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. Is preferred. 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 over the range, the improvement effect of the slipperiness cannot be expected.

In the polyolefin film of the present invention, the polyolefin having a melting point lower than that of the mixture of the base layer-forming polypropylene and the high-density polyethylene, which is the raw material resin for the surface layer, is not particularly limited. The melting point is preferably 10 to 80 ° C. lower than the melting point of the mixture of the base layer. Specific examples of such polyolefins include ethylene, propylene, 1-
Homopolymers of α-olefins such as butene, copolymers of the above α-olefins, copolymers of monomers other than α-olefins copolymerizable with the above α-olefins and α-olefins, and These mixtures and the like can be adopted 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 blended product containing these polyolefins as main components.

In the polyolefin film of the present invention, the thickness of the base layer is not particularly limited, but it 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 property to the film and prevents the cross-linked (meth) acrylic resin particles from being lost due to friction between the films, and also sufficiently causes 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.
The range is preferably 0 μm.

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

The polyolefin film of the present invention may be manufactured 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 to form a sheet, which is stretched 1.1 to 8 times in a uniaxial direction to obtain a uniaxially stretched sheet. Then, in order to form a surface layer, containing crosslinked (meth) acrylic resin particles,
A polyolefin having a low melting point is extruded into a sheet form from the base layer and laminated on the uniaxially stretched sheet. Alternatively, the laminated sheet can be further stretched 3 to 12 times in a direction substantially perpendicular to the direction of uniaxial stretching to obtain the polyolefin film of the present invention. It is also possible to extrude the base layer and the surface layer at the same time to laminate them, and stretch them uniaxially or biaxially by the same method as described above.

In the base layer and surface layer of the polyolefin film of the present invention, various additives which are known to be usually added to plastic films, for example, heat stabilizers, antioxidants, crystal nucleating agents and antistatic agents are used. , A lubricant, an antiblocking agent, an antibacterial agent, a freshness-retaining agent and the like may be added. Above all, in order to improve the slipperiness of the film, it is preferable to use a lubricant in the surface layer. Examples of the lubricant include higher fatty acid amides such as erucic acid amide, oleic acid amide, stearic acid amide, ethylenebisstearamide, N-
Stearyl erucic acid amide and the like can be preferably used. Usually, such a lubricant preferably contains erucic acid amide and oleic acid amide.

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 suitable opacity so that the inside cannot be seen through, it is preferably used as a packaging film for foods with a high water content, especially rice diapers.

FIG. 2 shows an example in which the polyolefin film of the present invention is used as an inner wrapping film for rice balls wrapped with seaweed.

That is, 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 diaper which can be eaten with seaweed is wrapped. In FIG. 1, the rice ball 1 is composed of two inner packaging films 2a and 2b made of the polyolefin film of the present invention.
The surface is covered and packaged. And the above 2
At least one edge (2a) of the two inner packaging films a and 2b has a folded structure inside, and most of the surface of the diaper 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, and the outer wrapping film and the inner wrapping film are bonded and fixed by heat sealing at predetermined locations on each edge. In addition, seaweed 6 is housed between the exterior film and the inner packaging films 2a and 2b. In such a rice ball package, the rupture portion 5 of the outer wrapping film is torn when edible,
By pulling both the inner and outer packaging films together in opposite directions of A and B and removing them from the rice ball, a seaweed-wrapped rice ball is easily completed. At this time, in the folded piece 3 of the inner wrapping film 2a, the film is not slid on the diaper in the pulling direction (direction A) but is peeled off from the diaper. Therefore, the folded-back piece 3 can be easily peeled off from the surface of the diaper 3 even though the diaper having high surface tackiness is packaged.

On the other hand, the folded-back piece 3 is in close contact with the surface of the inner packaging film 2a facing the folded-back piece in a wet state with the moisture of the diaper 1. However, since the inner wrapping film 2a is composed of the polyolefin film of the present invention, which has good slipperiness between the films as described above, the folding piece 3 can be easily used when the film is taken up. Slide on the opposite side of. As a result, in such a diaper bag, the inner wrapping film can be easily pulled from the diaper with a small resistance force.

Further, in such a diaper bag, even when a highly transparent film is used as the outer wrapping film 4, since the inner wrapping films 2a and 2b have appropriate opacity, the inner diaper has Not see through,
The musubi does not look wet and spoil its appearance.

[0035]

INDUSTRIAL APPLICABILITY The polyolefin film of the present invention is excellent in scratch resistance and heat sealability of the film and further improved in slipperiness between the films. Therefore, for example, when packaging diaper, the diaper can be taken out very smoothly when the package is opened, and the diaper may be cracked due to excessive force applied when the packaging is opened. Absent. In addition, it has excellent bag-making processability such as packaging process of seaweed, and does not easily cause film folding defects. Moreover, since the inside has appropriate opacity so that it cannot be seen through, the diaper will not be seen through with a wet feeling when the diaper is packaged and its commercial value will not be reduced. Further, it can be used for packaging by an automatic packaging machine by utilizing its heat sealing property.

Thus, the polyolefin film of the present invention is less likely to cause problems during film winding even during the production thereof due to the improvement in the slipperiness of the above-mentioned film. Is also very preferred.

[0037]

EXAMPLES Examples and comparative examples will be given below for specifically explaining the present invention, but the present invention is not limited to these examples. The film properties in the following examples and comparative examples were measured by the following methods.

(1) Haze Measured according to JIS K 6714.

(2) Scratch resistance Two films cut into 20 cm × 30 cm were stacked, one film was fixed on the lower side, and the other was on the upper side. Place a 4.6 kg weight on the upper film and the lower film and 10c.
The area of m × 10 cm was brought into contact, and the upper film was moved horizontally to rub back and forth between 20 cm twice. The haze was measured before and after the operation, and the difference between 0% and less than 3% was evaluated as ◯, 3% or more and less than 10% was evaluated as Δ, and 10% or more was evaluated as x.

(3) Sliding property I After forming the film, the ASTM-D-1 is prepared within 30 minutes at room temperature.
It measured according to the dynamic friction coefficient measuring method of 894.

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

(5) Heat-sealing property A heat-sealing bar of 5 × 200 mm was used, and at each set temperature, heat-sealing pressure was 1 kg / cm ² , and heat-sealing time was 1.0 seconds.
A sample of m width was cut out and measured at a pulling speed of 100 mm / min using a tensile tester. The result was an average value of 5 samples.

(6) Opening property of rice ball A double-sided heat-sealing polypropylene biaxially stretched film having a thickness of 20 μm was used as an outer packaging film. In addition,
This outer wrapping film is provided with an opening tape portion having a width of 3 mm coated with a hot melt agent as a breaking portion when opening. Each test film was used as an inner wrapping film, and an impulse sealing machine and a simple iron were used to prepare a diaper packing film having a structure as shown in FIG. A commercially available rice ball was actually packaged as shown in FIG. 2 with such a rice ball packaging film. The rice ball was actually opened and the openability of the rice ball was evaluated. Each test film was evaluated with 10 rice balls, and a 5-step evaluation was performed depending on whether or not the rice balls were cracked when opened.

5 points: 0 pieces of broken rice balls 4 points: 〃 1 to 2 pieces 3 points: 〃 3 pieces to 4 pieces 2 points: 〃 5 pieces to 6 pieces 1 point: 〃 7 pieces to 10 pieces (7 ) Translucency of Omusubi Each test film was attached to the surface of a commercially available Omusubi, and it was observed whether the surface of the Omusubi was visible through the film. When the film was opaque and the rice ball could not be seen through, the film was evaluated as ◯, and when the surface of the film was seen and the surface was wet and observed, it was evaluated as ×.

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

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

A flask equipped with a stirrer, an inert gas inlet tube, a reflux condenser and a thermometer was charged with polyoxyethylene alkylsulfoammonium (“Hitenol N-0”).
8 ", manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and charged with 900 parts of deionized water. A previously prepared mixture containing 70 parts of butyl acrylate, 30 parts of styrene, 1 part of azoisobutyronitrile and 5 parts of P-nitrobenzoic acid was charged, and T. K. A homogenizer (manufactured by Tokushu Kika Kogyo Co., Ltd.) was stirred at 8000 rpm for 5 minutes to form a uniform suspension. Then, the mixture was heated to 75 ° C. while blowing nitrogen gas, and the suspension polymerization reaction was carried out by continuing stirring at this temperature for 5 hours and then cooling. This suspension was filtered and then dried to obtain crosslinked acrylic resin particles. At this time, the nonvolatile content (emulsion-polymerized fine particles) contained in the filtrate was 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 for 10 minutes and 20% by weight of high-density polyethylene with a melt flow index at 190 ° C. of 1.0 g / 10 minutes and a density of 0.955 g / cm ³ was used to prepare a mixture using a T-die extruder. It was extruded into a sheet at a resin temperature of ° C and cooled and solidified by a chill roll maintained at 60 ° C to prepare a sheet having a thickness of 1.1 mm.

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

Next, the above sheet was stretched by a heating roll stretching machine at 150 ° C. for 4.8 times to obtain a 230 μm uniaxially stretched sheet. The above polyolefin 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 kept at 70 ° C. to obtain a 240 μm two-layer sheet.

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

Subsequently, this three-layer sheet was stretched 10 times at 160 ° C. using a transverse stretching machine to give a base layer made of a mixture of polypropylene and high-density polyethylene of 23.0.
A polyolefin film having a thickness of 2 μm and a surface layer of the polyolefin resin composition of 1.0 μm each was obtained. About the obtained polyolefin film haze, scratch resistance, slipperiness, heat sealability, openability of the rice ball, the transparency of the rice ball was measured,
The results are shown in Table 2.

Examples 4 to 10 In Example 3, the kind and content of the crosslinked (meth) acrylic resin particles to be contained in the surface layer, the thickness of the base layer and the surface layer, and the resin composition of the base layer are shown in Table 1. A polyolefin film was obtained in the same manner as in Example 3 except that it was changed. For the obtained polyolefin film, haze, scratch resistance, slipperiness, heat sealability, diaper openability, and diaper transparency were measured, 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 sphere 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 in. The rubber hardness A was measured according to JISK6301. The obtained polyolefin film was measured for haze, scratch resistance, slipperiness, heat sealability, diaper opening and diaper transparency, and the results are shown in Table 2.

Comparative Example 4 Melt Flow Index at 230 ° C. = 2.0 g
/ 10 min polypropylene using T-die extruder for 24
A polyolefin film was obtained in the same manner as in Example 3 except that the base layer was formed by extruding into a sheet at a resin temperature of 0 ° C. Haze for the obtained polyolefin film,
Scratch resistance, slipperiness, heat sealability, diaper openability, 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 ground silica particles having an average particle diameter of 1.8 μm and an average particle diameter of 2.0.
A polyolefin film was obtained in the same manner as in Example 1 except that the non-melting type silicone resin spherical particles having a size of μm were used. Haze for the obtained polyolefin film,
The scratch resistance, slipperiness, heat sealability, diaper openability, and diaper transparency were measured, and the results are shown in Table 2.

[0057]

[Table 1]

[0058]

[Table 2]

[Brief description of drawings]

FIG. 1 is a transverse cross-sectional view of a diaper that can be wrapped with seaweed and eaten as a wrapping film 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: Folding piece 4: Outer wrapping film 5: Broken part 6: Nori

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Claims (1)

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