CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit pursuant to 35 U. S. C. §119 (e) of U. S.

Provisional Application No. 60/523,109 filed on November 19,2003, and prioirity is claimed on Japanese Patent Application No. 2003-381996 filed November 12,2003, and U. S. Provisional Applications 60/523,109 filed on November 19,2003, the contents of which are incorporated herein by reference.

BACKGROUND ART The polyethylene-base film is being suitably used, for example, as a container into which food, medicament or the like is filled, or as a package for packaging a container made of various plastics or metals and filled with food, medicament or the like.

In the latter case, the package for packaging of container is used for various purposes, for

example, for protecting a container or container contents by preventing the container from mechanical damages such as flaw or by inhibiting the permeation or transmission of oxygen or ultraviolet ray to thereby prevent deterioration of the container contents, or for applying printing or the like to indicate the container contents or how to treat the container contents or the container.

The container or package for packaging of container is generally produced by shaping an ethylene-base polymer or a composition thereof to obtain a polyethylene-base film and forming the film into a desired shape (for example, bag) by heat sealing or the like.

Conventionally, the polyethylene-base film used for a container or a package for packaging of container sometimes causes mutual sticking of films with each other.

For example, during storage of a roll-wound film in a warehouse, the films are sometimes sticking each other to generate blocking. When blocking is generated, the film in the step of processing it into a bag or the like can be hardly processed into a good shape and moreover, due to bad slipping of the film, the productivity may decrease.

Furthermore, during storage after processing into a bag or the like until filling of contents, the container or package may cause mutual sticking of inner surfaces to each other to worsen the openability and the contents may not be easily filled.

In recent years, the occasion of subjecting a container package obtained by packaging a container with a package to high-pressure steam sterilization is increasing in view of safety and hygiene and moreover, for enhancing the productivity, this treatment tends to be performed by more elevating the sterilization temperature and thereby shortening the sterilization time. As the film is exposed to a higher temperature, mutual sticking is of course more readily generated. Particularly, in medical uses, for more stably maintaining constant the quality of container contents, the high-pressure steam

sterilization is recently performed under the conditions of readily causing mutual sticking, that is, by depressurizing the inside of the package to reduce the space volume between the medical container and the package and contact the package and the medical container with each other.

Particularly, in the case of a container using a propylene-base polymer for the surface coming into contact with the package (outermost layer of the container), the propylene-base polymer used is mostly a propylene-base copolymer in which, for the purpose of imparting flexibility to the container, ethylene or butene-1 is used as a copolymerization component or an elastomer component such as styrene-base elastomer or olefin-base elastomer is added. Between the propylene-base polymer or elastomer component-containing propylene-base polymer and a package comprising a polyethylene-base film, mutual sticking readily occurs. Among propylene-base polymers, when the container comprises a propylene-ethylene random copolymer, mutual sticking very readily takes place between the container and a package comprising a polyethylene-base film.

Under these circumstances, with an attempt to improve mutual sticking resistance or slipperiness of the polyethylene-base film, there have been proposed, for example, (a) a technique of adding an antiblocking agent comprising an inorganic or organic filler such as silica, talc or spherical crosslinking polymethyl methacrylate or adding a metal soap-base lubricant such as calcium stearate, a fatty acid amide-base lubricant widely used as a lubricant for film, such as erucic acid amide, or the like (see, for example, Japanese Patent No. 3,207, 500), (b) a technique of attaching a powder particle such as charged cornstarch powder to a film. surface, and (c) a technique of physically roughening a film surface by crimping or the like and thereby reducing the contact area (see, for example, Japanese Unexamined Patent Application, First

Publication No. Hei 10-95466).

However, these conventional techniques have the following problems.

In the technique of (a), when an antiblocking agent or an additive such as lubricant is added, the powder material drops from the cross section on cutting the film and contaminates the product or the additive bled out to the surface mingles into the contents to cause a problem in the hygiene. Similarly, the technique (b) of attaching a powder particle such as charged cornstarch powder is inevitably accompanied with a hygienic problem that the powder mingles into the contents. In particular, when a treatment such as high-pressure steam sterilization is performed while contacting the container and the package, additives contained in the package may permeate through the container wall depending on the construction material of the container and deteriorate the contents. The technique (c) of mechanically roughening the film surface has a problem such as bad film outer appearance.

The present invention has been made under these circumstances and an object of the present invention is to provide a technique capable of realizing a polyethylene-base film excellent in the mutual sticking resistance and slipperiness, freed from fears for mingling of foreign matters into the contents when a container or the like is constituted, and favored with excellent film outer appearance, and also provide articles using the polyethylene-base film having these properties, such as a container.

DISCLOSURE OF THE INVENTION The present inventors have found that by combining specific ethylene-base polymers, mutual sticking resistance and slipperiness can be remarkably enhanced substantially without adding additives such as lubricant and antiblocking agent. The present invention has been accomplished based on this finding. The reasons why the

mutual sticking resistance can be enhanced by the present invention are not necessarily elucidated, but it is presumed that by using a resin composition containing specific ethylene-base polymers, a film with at least one surface being uniformly roughened is obtained and by virtue of reduction in the contact area of the film, mutual sticking property decreases.

That is, the present invention provides: (1) a polyethylene-base film comprising multiple kinds of ethylene-base polymers differing in at least one of the composition, density and melt flow rate, wherein at least one of the multiple kinds of ethylene-base polymers is a high-density polyethylene, the dynamic friction coefficient of at least one side surface is 0.40 or less and the surface having a dynamic friction coefficient of 0.40 or less is a rough surface having a one-surface external haze value of 5% or more, (2) the polyethylene-base film as described in (1), wherein the polyethylene-base film does not contain substantially a lubricant and an antiblocking agent.

(3) the polyethylene-base film as described in (1), wherein the ratio MFRMA, /MFRMIN of the maximum value MFRMAx to the minimum value MFRMIN of melt flow rates of all ethylene-base polymers is from 5 to 200, and (4) the polyethylene-base film as described in (1), wherein the total amount of high-density polyethylenes contained is from 20 to 100 parts by mass per 100 parts by mass in total of ethylene-base polymers.

The definitions and measuring methods for the"melt flow rate","dynamic friction coefficient"and"one-surface external haze value"used in the present invention are described later.

Also, the present invention provides:

(5) a laminated body obtained by providing the polyethylene-base film described in (1) while disposing the rough surface as an outermost surface, (6) the laminated body as described in (5), wherein a sealant layer comprising the polyethylene-base film and using the rough surface as the sealant surface and at least one support layer for supporting the sealant layer are provided, and (7) the laminated body as described in (5), wherein at least one layer selected from a light-shielding layer, a gas barrier layer, a printing layer and a protective layer is provided in the inner side of the polyethylene-base film.

Also, the present invention provides: (8) a container comprising the polyethylene-base film described in (1) or the laminated body described in (5), (9) a package for packaging of container, comprising the polyethylene-base film described in (1) or the laminated body described in (5), with the innermost surface being the rough surface of the polyethylene-base film, (10) a container package obtained by contactedly housing a container in the package for packaging of container described in (9) and subjecting it to high-pressure steam sterilization, (11) the container package as described in (10), wherein the temperature at the high-pressure steam sterilization is 121°C or more, (12) the container package as described in (10), wherein the container is a medical container, and (13) the container package as described in (10), wherein at least the outermost layer of the container comprises a propylene-base polymer.

Also, the present invention provides: (14) an ethylene-base polymer composition comprising multiple kinds of

ethylene-base polymers differing in at least one of the composition, density and melt flow rate, wherein at least one of the multiple kinds of ethylene-base polymers is a high-density polyethylene, the dynamic friction coefficient of at least one side surface of a film obtained by shaping the composition at a resin temperature of ISO to 260°C is 0.40 or less and the surface having a dynamic friction coefficient of 0.40 or less is a rough surface having a one-surface external haze value of 5% or more, (15) the ethylene-base polymer composition as described in (14), wherein the ethylene-base polymer composition does not contain substantially a lubricant and an antiblocking agent, (16) the ethylene-base polymer composition as described in (14), wherein the ratio MFRMA/MFRMIN of the maximum value MFRMAX to the minimum value MFRMiN of melt flow rates of all ethylene-base polymers is from 5 to 200, and (17) the ethylene-base polymer composition as described in (14), wherein the total amount of high-density polyethylenes contained is from 20 to 100 parts by mass per 100 parts by mass in total of ethylene-base polymers.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.

Ethylene-Base Polymer Composition The ethylene-base polymer composition of the present invention is a composition comprising multiple kinds of ethylene-base polymers differing in at least one of the composition, density and melt flow late and containing at least a high-density polyethylene as the ethylene-base polymer.

The ethylene-base polymer is not particularly limited as long as it is a polymer mainly comprising ethylene, but examples thereof include a homopolymer of ethylene,

an ethylene-base polyolefin such as ethylene a-olefin copolymer comprising ethylene and a-olefin having from 3 to 20 carbon atoms, and a polar group-containing ethylene-base copolymer comprising ethylene and a polar group-containing compound copolymerizable with the ethylene.

Specific examples of the ethylene-base polyolefin include a high-density polyethylene, a linear low-density polyethylene and a high-pressure process low-density polyethylene. Examples of the oc-olefin used in the ethylene-base polyolefin include propylene, 1-butene, 1-pentane, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene and 1-dodecene, and these can be used individually or in combination of two or more thereof.

Among these a-olefins, preferred are 1-butene, 1-pentene, 1-hexen, 4-methyl-1-pentene and 1-octene because of their excellent heat resistance.

Specific examples of the polar group-containing ethylene-base copolymer include a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and (meth) acrylic acid, a metal salt thereof, a copolymer of ethylene and an alkyl ester of (meth) acrylic acid, and a copolymer of ethylene, an alkyl ester of (meth) acrylic acid, and an unsaturated dicarboxylic acid such as maleic anhydride.

Among ethylene-base copolymers, ethylene-base polyolefins are preferred, because when processed, for example, into a container, the taste or odor of food, medicament or the like less transfers to the contents. In the present invention, as described above, at least a high-density polyethylene is used as the ethylene-base polymer and the high-density polyethylene has not only these properties of ethylene-base polyolefin in general but also excellent heat resistance. Among ethylene-base polyolefins, a linear low-density polyethylene also has excellent heat resistance and therefore, it is preferred to use this polyethylene in combination.

The ethylene-base polymer can be produced by a known production method

such as bulk process, solution process, slurry process and vapor phase process. At the polymerization, a catalyst such as Ziegler-Natta catalyst and metallocene-base catalyst can also be used. Furthermore, in producing a low-density polyethylene or the like by a high-pressure process, a radical initiator is often used.

The ethylene-base polymers used all preferably have a melt flow rate (hereinafter referred to as"MFR") of 0.1 to 50 g/10 min as measured according to JIS K 7210 under the conditions of a temperature of 190°C and a load of 21. 18N. If the MFR is less than this range, the shapability tends to decrease, whereas if it exceeds this range, the strength and heat sealability tends to decrease.

The composition of the present invention comprises a high-density polyethylene as a first ethylene-base polymer. The"high-density polyethylene"as used herein means a polyethylene having a density of 940 kg/m3 or more as measured according to JIS K 6922-2. As the density is higher, the resistance against heat and mutual sticking is more excellent. In particular, the density of the high-density polyethylene used is preferably 945 kg/m3 or more, more preferably 950 kg/m3 or more, because excellent mutual sticking resistance can be obtained at a sterilization treatment performed at a temperature of 121 °C or more. The density of the high-density polyethylene is not particularly limited in its upper limit, but the density of commercially available high-density polyethylenes is maximally about 966 kg/m3 and those having a density lower than this are easily available. Also, in view of excellence in the shapability, heat resistance and heat bondability, the MFR of the high-density polyethylene used is preferably from 0.1 to 40 g/10 min, more preferably from 0.2 to 20 g/10 min.

The composition of the present invention further contains a second ethylene-base polymer differing from the first ethylene-base polymer in at least one of the composition, density and MFR.

The second ethylene-base polymer is not particularly limited, but an ethylene-base polyolefin is preferred because when processed, for example, into a container, the taste or odor of food, medicament or the like less transfers to the contents, and a high-density polyethylene or a linear low-density polyethylene is more preferred because excellent heat resistance can be obtained. In particular, the high-density polyethylene has excellent heat resistance and is preferably used as the second ethylene-base polymer. In the case of containing a high-density polyethylene as the second ethylene-base polymer, this is constituted to differ from the first ethylene-base polymer in the density and/or MFR.

The MFR of the second ethylene-base polymer is not particularly limited, but in view of excellence in shapability, heat resistance and heat bondability, the MFR is preferably from 0.1 to 40 g/10 min, more preferably from 0.2 to 20 g/10 min.

In the ethylene-base polymer composition of the present invention, the total amount of high-density polyethylenes contained is preferably from 20 to 100 parts by mass, more preferably from 40 to 100 parts by mass, per 100 parts by mass in total of ethylene-base polymers. If the total amount of high-density polyethylenes is out of this range, depending on the shaping conditions and the like, for example, fish eye is generated to worsen the film outer appearance. Furthermore, in the case of containing a high-pressure process low-density polyethylene, a linear low-density polyethylene and an ethylene-base copolymer, if the total amount of these polymers exceeds 80 parts by mass, the effect of enhancing the resistance against heat or mutual sticking may not be noticeably expressed.

The ratio MFRMAx/MFRMiN of the maximum value MFRAx to the minimum value MFRMN of MFRs of all ethylene-base polymers constituting the composition of the present invention is preferably from 5 to 200, more preferably from 10 to 150, still more

preferably from 10 to 100. The present inventors have found that when MFRM/MFRMIN is in such a range, the film surface can be stably roughened and good mutual sticking resistance can be obtained. The reason why good mutual sticking resistance is expressed with the MFR ratio is in a specific range is not necessarily elucidated, but it is presumed that when the MFR ratio is in the above-described range, a non-uniformly mixed state of ethylene-base polymers with each other is provided within the range capable of film shaping and the film surface is readily roughened.

If MFRMAx/MFRMIN is less than 5, the film surface can hardly become a rough surface and the dynamic friction coefficient tends to elevate, whereas if MFRMAx/MFRMiN exceeds 200, not only bad shapability results to cause generation of gel or fish eye and give a bad film outer appearance but also formation of a good rough surface disadvantageously becomes difficult.

The amount of the ethylene-base polymer having a maximum MFR (MFRMAx) is preferably from 20 to 80 parts by mass, more preferably from 30 to 70 parts by mass, still more preferably from 40 to 60 parts by mass, per 100 parts by mass in total of ethylene-base polymers, and within this range, a good rough surface can be readily formed.

The ethylene-base polymer having a maximum MFR (MFRMAx) is preferably a high-density polyethylene, because more excellent mutual sticking resistance is expressed. Particularly, for obtaining more excellent resistance against mutual sticking and heat, it is preferred that the ethylene-base polymer having a maximum MFR (MFRM, Y) and the ethylene-base polymer having a minimum MFR (MFRMIN) both are constituted by a high-density polyethylene and almost no resin component other than these two kinds of high-density polyethylenes is contained.

The composition of the present invention, which does not contain substantially a

lubricant and an antiblocking agent, satisfies the condition that the dynamic friction coefficient of at least one side surface of a film obtained by shaping the composition at a resin temperature of 180 to 260°C is 0.40 or less, preferably 0.35 or less, more preferably 0.3 or less. In particular, the dynamic friction coefficient of at least one side surface which is not contacted with a first roll at the shaping is preferably 0.40 or less. The "first roll"as used herein means, for example, in the case of a flat film shaping machine such as T-die film shaping machine, a first roll (chill roll) for cooling the melted resin extruded from the die, and in the case of a tubular film shaping machine such as inflation film shaping machine, a first roll used to flatten out the tubular film coming out from the die. That is, in the case of a tubular film obtained by inflation film shaping or the like, the"surface not contacted with a first roll"corresponds to the inner surface of the tubular film.

In either case, if the dynamic friction coefficient of the surface exceeds 0.40, bad slipperiness results and when the film is processed into a bag or the like, the productivity disadvantageously decreases.

The lower limit of the dynamic friction coefficient is not particularly but is preferably about 0.1. If the dynamic friction coefficient is excessively low, this may cause a trouble, for example, the film overly slips at the roll-winding of the film to fail in giving a smooth roll end face or at the laminate shaping or processing into a bag or the like, the film delivered from the roll slips on the delivering roll and proceeds meanderingly.

As the density of the high-density polyethylene used is higher or as the amount of the high-density polyethylene occupying in the total amount of the composition is larger, the dynamic friction coefficient advantageously tends to more decrease.

In the present invention, the"dynamic friction coefficient"is determined by

using two sheets made of the same polyethylene-base film, superposing the same surfaces, which are subjected to the same treatment, for example, surfaces which are not contacted with the chill roll, and measuring the dynamic friction coefficient according to JIS K 7125 under the conditions that the slipping rate is 100 mm/min, the load is 200 g, the contact region is a square having an area of 4,000 mm2 and the slipping direction is the M direction at the shaping of film.

The composition of the present invention, which does not contain substantially a lubricant and an antiblocking agent, also satisfies the condition that the surface having a dynamic friction coefficient of 0.40 or less of a film obtained by shaping the composition at a resin temperature of 180 to 260°C is a rough surface having a one-surface external haze value of 5% or more, preferably 8% or more. The"one-surface external haze value"is a value calculated according to the following formula (1) from a haze value Hi measured by uniformly coating a liquid paraffin on both surfaces of a film (internal haze value) and a haze value Hs measured by uniformly coating a liquid paraffin on only one surface (one-surface haze value), and this is a numerical value used as an index for the cloudiness correlated with the degree of surface roughening. In the present invention, these internal haze value and one-surface haze value are measured according to JIS K 7105.

One-surface external haze value = Hs-Hi (1) In the case of producing a container or a package for packaging of container by using a polyethylene-base film obtained from the composition of the present invention or a laminated body comprising this film, the container or package for packaging of container is preferably constituted such that the surface having a one-surface external haze value of 5% or more works out to the sealant surface (that is, inner surface). By such a constitution, good mutual sticking resistance and good openability are expressed.

If either surface of the film has a one-surface external haze value of less than 5%, the mutual sticking resistance and openability are not satisfied and this is not preferred.

As the density of the high-density polyethylene used is higher or as the amount of the high-density polyethylene occupying in the total amount of the composition is larger, the one-surface external haze value advantageously tends to more elevate.

The one-surface external haze value of a laminated body can be measured in the same manner, but in the case of having an opaque layer such as aluminum foil, the value is measured by excluding the opaque layer.

The composition of the present invention comprising the first and second ethylene-base polymers as essential components may further contain other one or multiple ethylene-base polymers differing from the first and second ethylene-base polymers in at least one of the composition, density and MFR.

Furthermore, other polymers may be appropriately blended within not departing from the object of the present invention. Examples of other polymers include, but are not limited to, propylene-base polymers and various styrene-base elastomers such as ethylene-a-olefin elastomer and styrene-butadiene elastomer. However, other polymers are preferably selected such that both the polymer having a maximum MFR and the polymer having a minimum MFR in all polymers are an ethylene-base polymer, because a non-uniformly mixed state large enough to give a good rough surface can be easily maintained.

For the purpose of improving the strength or reducing the volume or calorie at the disposal by burning, an organic or inorganic filler may be blended or other commonly employed known additives such as antistatic agent, antioxidant, anticlouding agent, organic or inorganic pigment, ultraviolet absorbent and dispersant may be appropriately blended, if desired, within the range of not seriously impairing the effect of the present

invention. However, it is necessary not to contain a lubricant and an antiblocking agent.

Specific examples of the lubricant include a metal soap-base lubricant such as calcium stearate and magnesium stearate, a lubricant containing a fatty acid ester of monohydric or polyhydric alcohol, such as ester of higher fatty acid having from 4 to 22 carbon atoms and linear aliphatic monohydric alcohol having 2,4 or 5 carbon atoms, tributyl acetylcitrate, di-2-ethylhexyl adipate, ethanediol montanate, poly (1, 3-butanedioladipate), methyl acetyllicinolate, poly (propylene glycol-adipate, laurate), poly (1, 3-butylene glycol, 1,4-butylene glycol, octyalcohol adipate), rice bran wax and diisodecyl adipate, and an acid amide-base lubricant such as oleic acid amide, erucic acid amide, behenic acid amide, ethylenebisoleic acid amide, hexamethylenebisoleic acid amide and ethylenebiserucic acid amide. Specific examples of the antiblocking agent include an organic fine particle comprising a crosslinked product such as polymethyl methacrylate, polystyrene and polyamide, and an inorganic fine particle such as silica, zeolite, kieselguhr, talc, kaolinite and amorphous aluminosilicate The term"containing substantially no lubricant and no antiblocking agent"as used herein means that the lubricant and antiblocking agent may be contained to such a degree of not bleeding out to the polyethylene-base film surface. More specifically, the allowable content of lubricant is less than 0.3% by mass, preferably less than 0.2% by mass, more preferably less than 0.1% by mass, in the composition. The allowable content of antiblocking agent is less than 0.05% by mass, preferably less than 0.03% by mass, more preferably 0.01% by mass, in the composition.

Among lubricants, the metal soap-base lubricant is sometimes inevitably contained to a minimum content because this is already contained in resin raw materials for the purpose of, for example, successfully pelletizing the raw material resin or

neutralizing and thereby trapping an acidic compound such as chlorine compound used as a catalyst at the production of polymer. Accordingly, at least an acid amide-base lubricant and a fatty acid ester-base lubricant which are widely used as a lubricant for film are preferably not contained. It is of course most preferred not to contain the lubricant and antiblocking agent at all, because of no fears for bleeding out.

The method for preparing the composition of the present invention is not particularly limited, but examples thereof include a method of mixing respective constituent components in a mixer such as mixing roll, Banbury mixer, Henschel, tumbler and ribbon blender, and a method of continuously polymerizing and pelletizing different ethylene-base polymers in at least one reactor. Among these, a method of obtaining the composition by continuous polymerization is preferred in view of profitability.

The composition of the present invention is constituted as described above and in the present invention, specific ethylene-base polymers are combined, whereby the mutual sticking resistance and slipperiness are remarkably enhanced substantially without adding a lubricant and an antiblocking agent.

The composition of the present invention has such properties and therefore, is suitable not only as a film but also as a material for articles formed by shaping such as blow molding, injection molding, compression molding and vacuum molding. The shaped article obtained by using the composition of the present invention exhibits excellent releasability at the shaping. Furthermore, a bottle obtained by blow molding or the like, and a container such as tray obtained by compression molding, vacuum molding or the like exhibits good drawing-out property when packaged in various packages.

Polyethylene-Base Film The polyethylene-base film of the present invention is obtained by shaping the above-described ethylene-base polymer composition of the present invention into a film form.

That is, the polyethylene-base film is characterized by comprising multiple kinds of ethylene-base polymers differing in at least one of the composition, density and melt flow rate, wherein at least one of the multiple kinds of ethylene-base polymers is a high-density polyethylene, the dynamic friction coefficient of at least one side surface is 0.40 or less, and the surface having a dynamic friction coefficient of 0.40 or less is a rough surface having a one-surface external haze value of 5% or more. Moreover, it is preferable for the polyethylene-base film not to contain substantially a lubricant and an antiblocking agent, As described above, in the case of producing a container or a package for packaging of container by using the polyethylene-base film of the present invention, the container or package for packaging of container is preferably constituted such that the rough surface (surface having a one-surface external haze value of 5% or more) of the polyethylene-base film works out to the sealant surface (that is, inner surface).

The polyethylene-base film of the present invention is obtained by subjecting the composition of the present invention or a pelletized product thereof from an extruder or the like to shaping according to various film shaping methods. Examples of the film shaping method include a water-cooling or air-cooling extrusion inflation and a T-die method. In the present invention, an unstretched film after shaping by a film shaping machine such as T-die shaping machine and inflation shaping machine can be directly used as the polyethylene-base film of the present invention. If desired, the film may be subjected to a stretching treatment, but in the case of use as a sealant film, the film is

preferably used in the state of unstretched film directly after the shaping by a film shaping machine, that is, unstretched film not subjected to a positive stretching treatment.

At the production of the polyethylene-base film of the present invention, the resin temperature is not particularly limited, but the resin temperature measured at the position immediately after the ejection from a die outlet at the film shaping is preferably from 180 to 260°C, more preferably from 190 to 250°C, still more preferably from 200 to 250°C. If the resin temperature exceeds 260°C, uniform mixing of ethylene-base polymers with each other proceeds and a rough surface may be difficult to form on the film surface, whereas if it is less than 180°C, insufficient mixing of ethylene-base polymers with each other may result to cause an outer appearance failure.

The thickness of the film of the present invention is not particularly limited, but in view of profitability and processability into a container or the like, the thickness is preferably from 5 to 1, 000 J. m, more preferably from 10 to 400, um, still more preferably from 30 to 200 jj. m.

The polyethylene-base film of the present invention is obtained by using the above-described composition of the present invention and therefore, this film is substantially containing no lubricant and no antiblocking agent and moreover, exhibits excellent mutual sticking resistance and slipperiness even without applying a physical treatment such as mechanical roughening of the film surface or formation of irregularities on the film surface by using a semi-mat roll, a mat roll, a double mat roll, an emboss roll, other special worked roll or the like. Of course, such a physical treatment may be applied to the polyethylene-base film of the present invention.

The polyethylene-base film of the present invention has excellent mutual sticking resistance and slipperiness and therefore, during storage in the roll-wound form,

mutual sticking of films with each other does not occur. Furthermore, in the processing into a container, a package for packaging of container or the like, the film successfully slips without causing blocking and therefore, the productivity of container or the like can be enhanced. Also, the film is electrically less chargeable and hardly attracts dusts or foreign matters, so that a high-quality container or the like can be stably produced. By using the polyethylene-base film of the present invention, a container, a package for packaging of container and the like, which are excellent in the mutual sticking resistance and capable of realizing successful filling of contents or smooth drawing out of the container from the package, can be provided.

In addition, the polyethylene-base film of the present invention does not contain additives such as antiblocking agent and lubricant and therefore, when a container or the like is constituted, foreign matters ascribable to additives are not mingled into the contents. Moreover, since a physical treatment such as mechanical roughening of the film surface is not necessary, an excellent film outer appearance can be obtained.

Furthermore, the polyethylene-base film of the present invention has a fine irregular shape on the film surface, so that a printing ink, an adhesive or the like can be easily and successfully attached by virtue of the anchor effect and superior printing property and the like can also be imparted.

Laminated Body The polyethylene-base film of the present invention can be used by itself as a single-layer sealant film or the like but can also be used in the form of a laminated body comprising the polyethylene-base film and other layers. The laminated body of the present invention is obtained by providing the polyethylene-base film of the present invention while disposing the rough surface (surface having a one-surface external haze

value of 5% or more) as an outermost surface. As described above, in the case of producing a container or a package for packaging of container by using the laminated body of the present invention, the container or package for packaging of container is preferably constituted such that the rough surface of the polyethylene-base film of the present invention works out to the sealant surface (that is, inner surface).

In an embodiment of the laminated body of the present invention suitable as a sealant film, for example, the laminated body has a constitution such that a sealant layer comprising the polyethylene-base film of the present invention and using the rough surface of the film as the sealant surface and at least one support layer for supporting the sealant layer are stacked by co-extrusion or the like. The support layer is not particularly limited, but a general polyolefin such as ethylene-base polymer and propylene-base polymer is preferably used and because of excellent interface adhesive strength between the sealant layer and the support layer, an ethylene-base polymer is more preferably used. Examples of the propylene-base polymer used include a homopolypropylene, a propylene-ethylene random copolymer and a propylene-ethylene block copolymer. Among these, a propylene ethylene block copolymer is preferred.

By using such a component for the support layer, higher transparency than that of a sealant film having a single layer constitution can be obtained.

The thickness of the entire laminated body is not particularly limited but in the case of use as a sealant film, by taking account of sealability, the thickness is preferably from 20 to 250, um, more preferably from 30 to 150 u. m. Also, the ratio of the thickness of the support layer to the thickness of the polyethylene-base film as the sealant layer (support layer/sealant layer) is not particularly limited, but by taking account of sealability, the ratio is preferably from 50 to 95/from 50 to 5.

In another embodiment of the laminated body of the present invention, the

laminated body has a constitution such that at least one layer selected from a light-shielding layer, a gas barrier layer, a printing layer and a protective layer is provided in the inner side of the polyethylene-base film of the present invention.

The constituent components for the light-shielding layer, gas barrier layer, printing layer and protective layer are not particularly limited, but examples thereof include a polyethylene, a polypropylene, an ethylene-vinyl acetate copolymer saponified product, an aluminum foil, a biaxially stretched or unstretched polyamide, a biaxially stretched or unstretched polyethylene terephthalate (PET) or polyethylene naphthalate (PEN), aluminum oxide-deposited PET and silica-deposited PET.

In still another embodiment of the laminated body of the present invention, the laminated body has a constitution such that at least one layer selected from a light-shielding layer, a gas barrier layer, a printing layer and a protective layer is further stacked on the above-described laminated body obtained by using the polyethylene-base film of the present invention as the sealant layer and stacking thereon at least one support layer for supporting the sealant layer.

The method for preparing the laminated body of the present invention is not particularly limited, but examples thereof include a method of shaping a laminated body while simultaneously stacking multiple layers by melt-shaping, such as water-cooling or air-cooling (co) extrusion (multilayer) inflation method and (co) extrusion (multilayer) T-die method, a method of previously shaping a film or sheet of each layer and as needed, stacking these layers by using an adhesive or the like, such as dry laminating method, and a method of previously shaping one party film or sheet and melt-laminating thereon another layer, such as extrusion laminating method. Among these, a dry laminating method and an extrusion laminating method are preferred because various kinds of layers can be easily stacked.

The laminated body of the present invention has an outermost surface assumed by the rough surface having a fine irregular shape of the polyethylene-base film of the present invention and therefore, is resistant against mutual sticking, similarly to the polyethylene-base film of the present invention.

In the case where the polyethylene-base film of the present invention is stacked on one surface of the support layer, a laminated body having high surface smoothness in the support layer side while expressing mutual sticking resistance can be obtained.

On the other hand, in the case where the polyethylene-base film of the present invention is used for both outer layers and two outermost surfaces both are assumed by the rough surface, the laminated body of the present invention can allow the film surfaces in the contacted state to slip from each other on delivering from the roll, for example, in the slitting step at the time of processing the laminated body of the present invention into a bag or the like, and a remarkable effect of preventing mutual sticking can be expressed.

Furthermore, the laminated body having such a constitution is electrically less chargeable to scarcely attract dusts or foreign matters and expresses excellent mutual sticking resistance and coupled with these properties, this laminated body can advantageously allow smooth travelling of the laminator or slitter roll.

In the laminated body of the present invention, the rough surface having a fine irregular shape of the polyethylene-base film of the present invention is used as the outermost surface, so that a printing ink, an adhesive or the like can be easily and successfully attached by virtue of the anchor effect and superior printing property and the like can also be imparted.

Container The container of the present invention is characterized by comprising the

polyethylene-base film of the present invention or the laminated body of the present invention.

In an embodiment of the container of the present invention, the container is, for example, a soft bag where the polyethylene-base film of the present invention is used as the innermost layer. In this embodiment, the rough surface. of the polyethylene-base film of the present invention is preferably used as the innermost surface. Such a container is excellent in the resistance against mutual sticking of container inner surfaces with each other, easily openable and therefore, freed from fears for generation of an opening failure, for example, at the filling of contents.

In another embodiment of the container of the present invention, the container is, for example, a bag or tray where the polyethylene-base film of the present invention is used as the outermost layer. In this embodiment, the rough surface of the polyethylene-base film of the present invention is preferably used as the outermost surface. The bag-like container can be obtained by melt-bonding the polyethylene-base film or laminated body of the present invention with heat, high frequency, ultrasonic wave or the like and thereby processing it into a bag or the like. The container where the polyethylene-base film of the present invention is used as the outermost layer is prevented from mutual sticking between containers when integrally packaged or stored in a pile. Also, when further outer-packaged by vacuum contact packaging or the like, the container expresses an extremely excellent taking-out property.

Particularly, the container comprising singly the polyethylene-base film of the present invention and the container comprising the laminated body of the present invention with the innermost layer and the outermost layer both comprising the polyethylene-base film of the present invention can have both of the above-described two effects and these containers are preferred. In the case of the container where the

innermost layer and the outermost layer both comprise the polyethylene-base film of the present invention, the rough surface of the polyethylene-base film of the present invention is preferably used as the innermost surface and the outermost surface.

In addition, the container of the present invention comprises the polyethylene-base film of the present invention or the laminated body of the present invention and therefore, is freed from fears for mingling of foreign matters into the contents and favored with excellent film outer appearance and also with superior printing property.

Package for Packaging of Container The package for packaging of container of the present invention is characterized by comprising the polyethylene-base film of the present invention or the laminated body of the present invention, with the innermost surface being the rough surface of the polyethylene-base film.

The package for packaging of container of the present invention is used for housing in the inside thereof a container comprising a synthetic resin or the like, particularly, a container comprising a soft and flexible material such as film, and this can be obtained by melt-bonding the polyethylene-base film or laminated body of the present invention with heat, high frequency, ultrasonic wave or the like and thereby processing it into a bag or the like.

According to the present invention, a package for packaging of container freed from fears for mutual sticking of inner surfaces with each other of the package or mutual sticking between the outer surface of the container housed and the inner surface of the package can be obtained. In addition, the package for packaging of container of the present invention comprises the polyethylene-base film of the present invention or the

laminated body of the present invention and therefore, is freed from fears for mingling of foreign matters into the contents and favored with excellent film outer appearance and also with superior printing property.

Container Package The container package of the present invention is obtained by contactedly housing a container in the package for packaging of container of the present invention and subjecting it to high-pressure steam sterilization.

The container for use in the container package of the present invention is not particularly limited, but in view of shapability and profitability, examples thereof include a bag-like container comprising a synthetic resin-made sheet or film having a single-layer or multilayer structure. As for the container material, in addition to polyethylene, vinyl chloride and the like which have been conventionally used, a highly heat-resistant propylene-base polymer is used.

The high-pressure steam sterilization can be practiced by a method commonly used in the field of retort, medical care and the like, such as submersion in water or spraying.

The high-pressure steam sterilization temperature is not particularly limited, but from the standpoint of maintaining the flavor of food or the like or enhancing the sterilization effect, the temperature which has been heretofore approximately from 100 to 118°C recently tends to gradually elevate and in recent years, the treatment is practiced at a high temperature of 121°C or more. Furthermore, the high-pressure steam sterilization is practiced in many cases by depressurizing the inside of the package to contact the container and the package. It is also increasing to perform the high-pressure steam sterilization by housing together a tube, a connector or the like used on use of the

container and depressurizing the inside of the package to contact the container, package and other housed materials.

The container package of the present invention is excellent in the heat resistance and also remarkably excellent in the mutual sticking resistance after high-pressure steam sterilization at 121°C or more. In general, a container comprising a soft sheet or film made of a polyolefin-base resin readily causes mutual sticking due to contact with a package, but the container package of the present invention is freed from mutual sticking even in such a case. In particular, as described above in the"BACKGROUND ART", in the case of a container using a propylene-base polymer for the surface coming into contact with the package (outermost layer of the container), particularly a container comprising a propylene-base copolymer or a propylene-base polymer containing an elastomer component, mutual sticking readily occurs between the container and the package and drawing out of the container after opening the container package may encounter difficulty in some cases. The container package of the present invention has excellent mutual sticking resistance and therefore, the container can be very easily taken out. In this way, the mutual sticking resistance effect of the present invention is more clearly exerted in the container package housing a container with the outermost layer comprising a propylene-base polymer.

Furthermore, the container package of the present invention is freed from generation of mutual sticking even under severe conditions of a high-pressure steam sterilization treatment where the container and the package are laid in a strongly contacted state by depressurizing the inside of the package.

The present invention can be suitably applied, for example, to a container package for housing a medical container or a food container, particularly to a container package having packaged therein a medical container such as film bag, blown bag or

blown bottle filled with contents such as high calorie infusion or infusion for peritoneal dialysis (CAPD). In the present invention, additives such as lubricant and antiblocking agent are substantially not used and this eliminates fears that such an additive bleeds out to contaminate the container contents, and ensures very high hygiene.

Examples The present invention is described in greater detail below by referring to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Examples 1 to 7 and Comparative Examples 1 to 8 Composition Ethylene-base polymers and additives were blended to give a composition shown in Tables 1 and 2 and these were mixed by a Henschel mixer to obtain an ethylene-base polymer composition. Subsequently, this composition was shaped at a resin temperature of 230°C by a T-die shaping machine equipped with a mirror roll as the first roll for cooling to obtain a polyethylene-base film having a thickness of 70 um. In Tables, the unit of the amount blended is parts by mass.

Package The obtained film was cut into a square of 35 cm x 35 cm and by preparing two sheets of this film, the surfaces not contacted with the first roll for cooling were superposed and heat-sealed to each other at three edge parts to obtain a bag-like package for packaging of container. The heat-sealing was performed under the conditions such

that the seal width was 1 cm, the temperature at the upper part of heat seal bar was 180°C, the temperature at the lower part was 60°C, the pressure was 0.2 MPa and the treatment time was 1 second.

Container Separately, a propylene ethylene random copolymer having an MFR of 2 g/10 min as measured according to JIS K7210 at 230°C under a load of 21.18 N was shaped at a temperature of 230°C by a T-die shaping machine to obtain a film having a thickness of 200 p. m. The obtained film was cut into a square of 20 cm x 20 cm and two sheets of this film were superposed and heat-sealed to each other at three edge parts to prepare a bag-like container to be housed in the package prepared above. The heat-sealing was performed under the conditions such that the seal width was 1 cm, the temperature at the upper part of heat seal bar was 210°C, the temperature at the lower part was 60°C, the pressure was 0.2 MPa and the treatment time was 1 second.

After filling 1 L of distilled water in this container, the edges not melt-bonded were heat-sealed to each other to close the container.

Container Package The container containing distilled water was housed in the package prepared above and while depressurizing the inside of the package by a vacuum pump, the opening part of the package was heat-sealed to obtain a container package. This container package was further subjected to a sterilization treatment at 124°C for 30 minutes in a spray-system high-pressure steam sterilizer.

The ethylene-base polymers, antiblocking agents and lubricants used are shown

below. The MFR was measured according to JIS K 7210 at a temperature of 190°C under a load of 21.18 N, and the density was measured according to JIS K 6922-2 by a density gradient tube. In Tables, MFRMAx/MFRMiN is also shown together.

Ethylene-Base Polymers HD1 : high-density polyethylene having an MFR of 15 g/10 min and a density of 965 kg/m3 HD2: high-density polyethylene having an MFR of 8 g/10 min and a density of 955 kg/m3 HD3: high-density polyethylene having an MFR of 0.2 g/10 min and a density of 960 kg/m3 HD4: high-density polyethylene having an MFR of 0.6 g/10 min and a density of 955 kg/m3 HD5 : high-density polyethylene having an MFR of 5 g/10 min and a density of 955 kg/m3 HD6: high-density polyethylene having an MFR of 12 g/10 min and a density of 955 kg/m3 HD7 : high-density polyethylene having an MFR of 0.08 g/10 min and a density of 950 kg/m3 LL1 : an ethylene#1-hexene copolymer which is a linear low-density polyethylene having an MFR of 0. 5 g/10 min and a density of 922 kg/m3 LL2: an ethylene l-hexene copolymer which is a linear low-density polyethylene having an MFR of 15 g/10 min and a density of 935 kg/m3 LL3: an ethylene l-butene copolymer which is a linear low-density polyethylene having an MFR of 0.2 g/10 min and a density of 935 kg/m3

LD 1 : high-pressure process low-density polyethylene having an MFR of 50 g/10 min and a density of 917 kg/m3 Additives Cl : silica-base antiblocking agent C2: polymethyl methacrylate (PMMA)-base antiblocking agent C3: erucic acid amide Evaluation Items and Evaluation Methods Dynamic Friction Coefficient The dynamic friction coefficient of the polyethylene-base film was measured according to JIS K 7125 by superposing surfaces, which were not contacted with the first roll and setting the conditions such that the slipping rate was 100 mm/min, the load was 200 g, the contact region was a square having an area of 4,000 mm2 and the slipping direction was the M direction at the shaping of film.

One-Surface External Haze Value The one-surface external haze value of polyethylene-base film was measured according to JIS K 7105. More specifically, as the one-surface haze value (Hs), a haze value was measured by coating a liquid paraffin on the surface opposite the surface where the dynamic friction coefficient of polyethylene-base film was measured. Then, as the internal haze value (Hi), a haze value was measured by coating a liquid paraffin on another surface. From these values, the one-surface external haze value was calculated according to formula (1).

Film Outer Appearance The container package (30 cm x 30 cm) after high-pressure steam sterilization was partitioned into 9 regions each in a size of 10 cm x 10 cm, the roughness state on the surface was observed with an eye, the number of regions having a uniform and ground glass-like good outer appearance and the number of regions having a non-uniformly surface-roughened bad outer appearance were counted and the sample was rated according to the following criteria.

The number of regions having a good outer appearance was from 7 to 9.

A : The number of regions having a good outer appearance was from 4 to 6.

The number of regions having a good outer appearance was from 0 to 3.

Mutual Sticking Resistance The container package after high-pressure steam sterilization was opened by cutting and the container with distilled water was manually taken out from the container package. Based on the easiness in drawing out from the package, the mutual sticking between inner surfaces of the package and the mutual sticking between the package and the container were evaluated according to the following criteria. o : The container package was easily opened and the container with distilled water could be easily taken out without sticking to the package.

The container package was difficult to open and even if opened, the container with distilled water was firmly sticking to the package and could not be easily taken out.

Results

Evaluation results are shown together in Tables 1 and 2.

As seen in Table 1, in all of Examples 1 to 7 where two kinds of high-density polyethylenes or a high-density polyethylene and a linear low-density polyethylene were blended, the obtained polyethylene-base film had a dynamic friction coefficient of 0.40 or less and a one-surface external haze value of 5% or more and from the container package prepared by housing a container in the package using this film, the container could be very easily taken out without causing mutual sticking between inner surfaces of the package or between package and container even after applying a severe treatment of performing high-pressure steam sterilization at 121°C or more while depressurizing the inside of the container, despite not containing a lubricant or an antiblocking agent in the package. Furthermore, it is revealed that in the present invention, even when a container comprising a propylene-base copolymer easy to cause mutual sticking was used, good mutual sticking resistance described above was expressed. In addition, the obtained package had a good film outer appearance.

On the other hand, in Comparative Examples 1 and 5 where only one high-density polyethylene was blended as the ethylene-base polymer, the obtained polyethylene-base film had a large dynamic friction coefficient exceeding 0.4 to give bad slipperiness and had an insufficient one-surface external haze value of less than 5.0% and the package using this film was extremely poor in the mutual sticking resistance.

In Comparative Examples 2 to 4 where only one high-density polyethylene was blended as the ethylene-base polymer and a lubricant or antiblocking agent was added, the obtained polyethylene-base film had a dynamic friction coefficient of 0.4 or less to give good slipperiness, but the package using this film was still extremely poor in the mutual sticking resistance. Furthermore, in Comparative Examples 2 and 3 where the antiblocking agent was blended in a large amount of 0.5 parts by mass per 100 parts by

mass of the ethylene-base polymer, the obtained package had an extremely bad film outer appearance.

In Comparative Example 6 where a high-density polyethylene was not blended as the ethylene-base polymer but only two kinds of linear low-density polyethylenes were blended, the obtained polyethylene-base film had a good dynamic friction coefficient and a good one-surface external haze value, but the package using this film was extremely bad in the film outer appearance and the mutual sticking resistance.

In Comparative Example 7 where two kinds of high-density polyethylenes were blended but MFRMAX/MFRMIN was less than 5, the obtained polyethylene-base film had a dynamic friction coefficient exceeding 0.4 and a one-surface external haze value of less than 5.0% and the package using this film was extremely poor in the mutual sticking resistance.

In Comparative Example 8 where a high-density polyethylene and a high-pressure process low-density polyethylene were blended as the ethylene-base polymer and MFRMAX/MFRMIN was exceeding 200, the obtained polyethylene-base film had a dynamic friction coefficient exceeding 0.4 and the package using this film was extremely bad in the film outer appearance and the mutual sticking resistance.

Table 1 Additive Dynamic One-Surface Mutual Ethylene-Base Polymer Film Outer MFRMAX/MFRMIN Friction External Haze Value Sticking (blending ratio) (amount blended) Appearance Coefficient (%) Resistance Example 1 HD1/HD3 - 75 0.25 10.0 # # (30/70) Example 2 HD1/HD3 - 75 0.21 8.6 # # (50/50) Example 3 HD2/HD4 - 13 0.30 8.6 # # (80/20) Example 4 HD2/HD4 - 13 0.28 8.2 # # (50/50) Example 5 HD5/LL1 - 10 0.38 8.5 # # (70/30) Example 6 HD3/HD6 - 60 0.22 9.5 # # (50/50) Example 7 HD7/HD1 - 188 0.33 6.0 # # (50/50) Table 2 Additive Dynamic One-Surface Mutual Ethylene-Base Polymer Film Outer MFRMAX/MFRMIN Friction External Haze Value Sticking (blending ratio) (amount blended) Appearance Coefficient (%) Resistance Comparative HD2 - - 0.48 1.5 # # Example 1 (100) Comparative HD1 Cl - 0.30 4.5 # # Example 2 (100) (0.5) Comparative HD2 C2 - 0.32 3.5 # # Example 3 (100) (0.5) Comparative HD2 C3 - 0.32 3.5 # # Example 4 (100) (0.1) Comparative HD5 - - 0.52 2.0 # # Example 5 (100) Comparative LL2/LL3 - 75 0.31 8.2 # # Example 6 (50/50) Comparative HD2/HD5 - 1.6 0.50 2.2 # # Example 7 (50/50) Comparative HD3/LD1 - 250 0.85 8.5 # # Example 8 (50/50)

INDUSTRIAL APPLICABILITY In the present invention, specific ethylene-base polymers are combined, whereby mutual sticking resistance and slipperiness are remarkably enhanced substantially without adding additives such as lubricant and antiblocking agent and also without applying a physical treatment such as mechanical roughening of the film surface.

According to the present invention, an ethylene-base polymer composition, a polyethylene-base film and a laminated body, which are excellent in the mutual sticking resistance and slipperiness, excellent in the safety and hygiene with no fears for mingling of foreign matters into the contents when a container or the like is constituted, and also excellent in the film outer appearance, can be provided. Furthermore, by using the polyethylene-base film or laminated body of the present invention, a container, a package for packaging of container and a container package, which are excellent in the mutual sticking resistance and slipperiness, excellent in the safety and hygiene with no fears for mingling of foreign matters into the contents, and also excellent in the film outer appearance, can be provided.

The polyethylene-base film of the present invention comprises an inexpensive polyolefin and therefore, is low in the cost and its industrial value is very high.

The ethylene-base polymer composition of the present invention and the polyethylene-base film and laminated body each using the composition are excellent in the mutual sticking resistance and slipperiness, freed from fears for mingling of foreign matters into the contents when a container or the like is constituted, and favored with excellent film outer appearance, so that these can be preferably applied, for example, to a medical container or a food container such as film bag, blown bag or blown bottle for filling therein a high calorie infusion, an infusion for peritoneal dialysis (CAPD) or the like, to a container package for packaging such a container, and to a container package

having packaged therein a medical container such as film bag, blown bag or blown bottle filled with contents such as high calorie infusion or infusion for peritoneal dialysis (CAPD). In the present invention, additives such as lubricant and antiblocking agent are substantially not used and this eliminates fears that such an additive bleeds out to contaminate the container contents, and ensures very high hygiene.