JP6933242B2 - Multilayer film - Google Patents

Description

The present invention relates to a multilayer film.

In recent years, as a medical packaging, a deep-drawn package (sometimes referred to as a "deep-draw package" in the present specification) has been used. The deep-drawn package is formed by joining a bottom material made of a multilayer film having a recess forming a storage part in the center and a lid material made of polyethylene non-woven fabric or sterilized paper by heat sealing or the like. Has been done. Then, a gauze for business use, a cotton swab, a medical device, and the like are stored in the recess.

As a multilayer film used for such an application, for example, a film in which an outer layer of nylon and an inner moisture-proof layer are laminated is disclosed (see Patent Document 1).

Japanese Unexamined Patent Publication No. 03-187734

However, with conventional multilayer films such as those disclosed in Patent Document 1, when a molded product is manufactured by heat molding, the desired shape of the molded product cannot be normally reproduced, and the moldability is high. There was a problem that there was something inferior to.

An object of the present invention is to provide a multilayer film having excellent moldability during heat molding.

In order to solve the above problems, the present invention adopts the following configuration.
[1]. A multilayer film, the multilayer film includes a sealant layer, a first protective layer, and a second protective layer. The sealant layer is one outermost layer of the multilayer film, and the second protective layer. Is arranged between the sealant layer and the first protective layer without contacting the first protective layer, and when the thickness of the multilayer film is T, the second protective layer Is a multilayer film arranged at a distance of 0.1T to 0.45T from the surface of the sealant layer opposite to the first protective layer side.
[2]. The multilayer film according to [1], wherein the multilayer film further includes a first base material layer between the first protective layer and the second protective layer.
[3]. The multilayer film according to [1] or [2], wherein the sealant layer contains linear low-density polyethylene.

[4]. The molecular weight distribution (Mw / Mn) of the linear low-density polyethylene is 7.0 or less, and the number average molecular weight (Mn) of the linear low-density polyethylene is 20000 or more, according to [3]. Multilayer film.
[5]. The multilayer film according to any one of [1] to [4], wherein the first protective layer and the second protective layer contain the same constituent materials.
[6]. The multilayer film according to any one of [1] to [5], wherein the first protective layer and the second protective layer contain a polyamide.
[7]. The multilayer film according to any one of [2] to [6], wherein the first base material layer contains linear low-density polyethylene.

According to the present invention, there is provided a multilayer film having excellent moldability during heat molding.

It is sectional drawing which shows typically an example of the multilayer film of this embodiment. It is sectional drawing which shows typically an example of the conventional multilayer film. It is sectional drawing which shows typically the package which was constructed by using the multilayer film of this embodiment.

<< Multilayer film >>
The multilayer film according to the embodiment of the present invention includes a sealant layer, a first protective layer, and a second protective layer, and the sealant layer is one outermost layer of the multilayer film and is the second protective layer. The layer is arranged between the sealant layer and the first protective layer without contacting the first protective layer, and when the thickness of the multilayer film is T, the second protection is provided. The layer is arranged at a distance of 0.1T to 0.45T from the surface of the sealant layer opposite to the first protective layer side.
By having such a structure, the multilayer film of the present embodiment can normally reproduce the target shape in the molded product when the molded product is manufactured by heat molding, and is excellent in moldability.

Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, in the figure used in the following description, in order to make it easy to understand the features of the present invention, the main part may be enlarged and shown, and the dimensional ratio of each component is the same as the actual one. Is not always the case.

FIG. 1 is a cross-sectional view schematically showing an example of the multilayer film of the present embodiment.
The multilayer film 1 shown here includes a sealant layer 13, a first protective layer 11, and a second protective layer 12.
The sealant layer 13 is one outermost layer of the multilayer film 1, and the first protective layer 11 is the other outermost layer of the multilayer film 1.
In the multilayer film 1, the second protective layer 12 is arranged between the sealant layer 13 and the first protective layer 11. However, the second protective layer 12 is not in contact with the first protective layer 11.
That is, in the multilayer film 1, the sealant layer 13, the second protective layer 12, and the first protective layer 11 are laminated in this order in the thickness direction thereof, except that the second protective layer 12 is the first protective layer 11. It is arranged and configured without contact with.

The multilayer film 1 further includes a first base material layer 14 between the first protective layer 11 and the second protective layer 12.

The multilayer film 1 further includes a second base material layer 15 between the second protective layer 12 and the sealant layer 13.
Here, the second base material layer 15 is arranged in direct contact with the sealant layer 13.

The multilayer film 1 further includes between the first protective layer 11 and the first base material layer 14, between the first base material layer 14 and the second protective layer 12, and between the second protective layer 12 and the second base layer 12. An adhesive layer 16 is provided between the material layer 15 and the material layer 15.

In this way, the multilayer film 1 includes the sealant layer 13, the second base material layer 15, the adhesive layer 16, the second protective layer 12, the adhesive layer 16, the first base material layer 14, the adhesive layer 16 and the first protective layer 11. Are laminated in this order in these thickness directions.

The surface of the sealant layer 13 opposite to the first protective layer 11 side (sometimes referred to as the "second surface" in the present specification) 13b is one outermost surface of the multilayer film 1 (in the present specification). Is sometimes referred to as the "second surface") 1b.
The surface of the first protective layer 11 opposite to the sealant layer 13 side (sometimes referred to as the "first surface" in the present specification) 11a is the other outermost surface of the multilayer film 1 (in the present specification). Is (sometimes referred to as a "first surface") 1a.

When the thickness of the multilayer film 1 (in other words, the distance between the first surface 11a of the first protective layer 11 and the second surface 13b of the sealant layer 13) is T, the second surface of the multilayer film 1 is the second. The protective layer 12 is arranged at a distance of 0.1T to 0.45T from the second surface 13b of the sealant layer 13.
In other words, in the multilayer film 1, the surface of the second protective layer 12 on the sealant layer 13 side (sometimes referred to as the “second surface” in the present specification) 12b and the second surface 13b of the sealant layer 13 The distance D between, is 0.1T to 0.45T.

In terms of the higher moldability of the multilayer film 1 during heat molding, in the multilayer film 1, the second protective layer 12 is, for example, 0.12T to 0.44T from the second surface 13b of the sealant layer 13. , 0.15T to 0.42T, 0.2T to 0.41T, and 0.2T to 0.4T.

The thickness T of the multilayer film 1 is preferably 60 to 180 μm, more preferably 80 to 160 μm, and even more preferably 90 to 120 μm.
Hereinafter, the configuration of each layer will be described in more detail.

<Sealant layer>
The sealant layer 13 is a layer that can be heat-sealed with each other or with other members.
The second surface 13b of the sealant layer 13 is a sealing surface.
The sealant layer 13 may or may not have an easy peel property that exhibits pseudo-adhesiveness with the adherend.

Hereinafter, first, the sealant layer 13 having no easy peeling property will be described.
Such a sealant layer 13 is preferably a resin layer containing a resin, and more preferably a resin layer containing a polyolefin-based resin. Such a sealant layer 13 can be heat-sealed more easily.

The resin contained in the sealant layer 13 may be of only one type, of two or more types, and when there are two or more types, the combination and ratio thereof can be arbitrarily selected according to the purpose. ..

The polyolefin-based resin is not particularly limited as long as it is a resin having a constituent unit derived from an olefin, and may be, for example, a copolymer having only one constituent unit or two constituent units. The above-mentioned copolymer may be used, and the copolymer may be, for example, either a block copolymer or a random copolymer.

Examples of the polyolefin resin include polyethylene (PE), polypropylene (PP), ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), and ethylene-methacrylate copolymer (EMAA). ), Ethylene-methyl acrylate copolymer (EMA), ethylene-methyl methacrylate copolymer (EMMA), ethylene-ethyl acrylate copolymer (EEA), ionomer resin (ION resin) and the like.
Examples of the polyethylene include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE, for example, metallocene-catalyzed linear low-density polyethylene (mLLDPE), etc.).
The ionomer resin is, for example, a resin in which a copolymer of ethylene and a small amount of acrylic acid or methacrylic acid has an ion cross-linking structure by salt formation of an acid portion thereof and metal ions. Can be mentioned.
In addition, in this specification, a simple description of "low density polyethylene" means "low density polyethylene other than linear low density polyethylene" unless otherwise specified.

As the preferred polyolefin-based resin, polyethylene is mentioned in that it is a general-purpose resin and inexpensive.

The sealant layer 13 is particularly preferably containing a linear low-density polyethylene among the polyethylenes, because the sealant layer 13 is particularly excellent in sealing property.

The sealant layer 13 may contain the resin and other non-resin components.
Examples of the non-resin component include additives known in the art.
Examples of the additive include antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, thickeners, thickeners, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers and the like. Can be mentioned.

The non-resin component contained in the sealant layer 13 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be arbitrary depending on the purpose. You can choose.

In the sealant layer 13, the ratio of the content of the resin to the total mass of the sealant layer 13 is preferably 80% by mass or more, more preferably 90% by mass or more, for example, 95% by mass or more. It may be either 97% by mass or more and 99% by mass or more. When the ratio is at least the lower limit value, the sealing property of the sealant layer 13 becomes higher.
The upper limit of the ratio is not particularly limited, and the ratio may be 100% by mass or less.

In the sealant layer 13, the ratio of the content of the polyolefin resin to the content of the resin is preferably 80% by mass or more, more preferably 90% by mass or more, for example, 95% by mass or more. , 97% by mass or more and 99% by mass or more. When the ratio is at least the lower limit value, the sealing property of the sealant layer 13 becomes higher.
The upper limit of the ratio is not particularly limited, and the ratio may be 100% by mass or less.

Next, the sealant layer 13 having an easy peel property will be described.
Of the easy-peel sealant layers 13, those suitable for use with resin adherends (in the present specification, such sealant layers are referred to as "easy-peel type 1 sealant layers". (There is), for example, those containing an ethylene-vinyl acetate copolymer (EVA) can be mentioned.

The easy peel type 1 sealant layer 13 may contain only an ethylene-vinyl acetate copolymer (that is, may be composed of an ethylene-vinyl acetate copolymer), or may be composed of an ethylene-vinyl acetate copolymer. The polymer and other components (sometimes referred to as "other components" in the present specification) may be contained (that is, the ethylene-vinyl acetate copolymer and the other components). It may consist of).

The other component contained in the sealant layer 13 of Easy Peel Type 1 is not particularly limited and may be arbitrarily selected depending on the intended purpose. For example, it may be either a resin component or a non-resin component.

The other component, which is a resin component, is a resin other than the ethylene-vinyl acetate copolymer.
The other component, which is a resin component, may be a homopolymer having only one constituent unit, or may be a copolymer having two or more constituent units.
More specifically, as the other component which is a resin component, for example, an ethylene-methacrylic acid copolymer, an ionomer resin (ION resin), a polyolefin such as polypropylene, and an olefin copolymer such as an ethylene propylene copolymer. And so on. The sealant layer 13 containing these other components (resin components) has higher easy peeling properties. The ionomer resin, which is the other component, is the same as that described above.

Examples of the other component, which is a non-resin component, include additives known in the art.
Examples of the additive as a non-resin component include the same additives as those described above as those contained in the sealant layer 13 having no easy peeling property.

The other components contained in the sealant layer 13 of Easy Peel Type 1 may be only one kind, two or more kinds, and when there are two or more kinds, the combination and ratio thereof are the object. It can be selected arbitrarily according to.

In the sealant layer 13 of Easy Peel Type 1, the ratio of the content of the ethylene-vinyl acetate copolymer to the total mass of the sealant layer 13 is preferably 5% by mass or more, and preferably 10% by mass or more. More preferably, it may be any of, for example, 30% by mass or more, 50% by mass or more, and 70% by mass or more. When the ratio is equal to or higher than the lower limit value, the easy peelability of the sealant layer 13 becomes higher.
The upper limit of the ratio is not particularly limited, and the ratio may be 100% by mass or less.

Among the easy-peel sealant layers 13, those suitable for use on sterilized paper as an adherend (in the present specification, such a sealant layer is referred to as "easy-peel type 2 sealant layer". (May be) include, for example, those containing linear low density polyethylene (LLDPE).

The multilayer film 1 provided with the easy peel type 2 sealant layer is suitable for producing a medical packaging body. By performing deep drawing molding on such a multilayer film 1, a molded body (sometimes referred to as a “bottom material” in the present specification) having recesses constituting a storage portion in the package is produced. However, with medical equipment such as commercial gauze, cotton sticks, and medical equipment stored in the recess, sterile paper and heat, which are adherends (sometimes referred to as "lid material" in the present specification). By sealing, a medical packaging body in which the medical device is stored in the recess (storage portion) can be obtained. Such medical packaging is classified as a deep-squeezed packaging, and since the sterilized paper is breathable, it can be sterilized with a sterilizing gas before its use, and it is sterilized at the time of its use. The paper can be easily peeled off. The deep-drawn package will be described in more detail later.

The molecular weight distribution (Mw / Mn) of the linear low-density polyethylene is preferably 7.0 or less, more preferably 5.0 or less, further preferably 4.0 or less, and 3 It is particularly preferably 5.5 or less.
The number average molecular weight (Mn) of the linear low-density polyethylene is preferably 20,000 or more, more preferably 25,000 or more, further preferably 28,000 or more, and particularly preferably 30,000 or more. ..
The linear low-density polyethylene preferably satisfies both the conditions of these molecular weight distributions and the number average molecular weight. By using such a linear low-density polyethylene, foreign matter adhesion on the molding hot plate (sometimes referred to simply as "hot plate" in the present specification) is suppressed during molding of the multilayer film. .. That is, such a linear low-density polyethylene has a high ability to prevent equipment contamination due to foreign matter adhesion, and makes it possible to prolong the continuous operation of equipment related to molding, for example.

From this point of view, in the present embodiment, the molecular weight distribution (Mw / Mn) of the linear low-density polyethylene is 7.0 or less, and the number average molecular weight (Mn) of the linear low-density polyethylene is It is preferably 20,000 or more, for example, the molecular weight distribution (Mw / Mn) of the linear low-density polyethylene is 5.0 or less, and the number average molecular weight (Mn) of the linear low-density polyethylene is 25,000 or more. The molecular weight distribution (Mw / Mn) of the linear low-density polyethylene may be 4.0 or less, and the number average molecular weight (Mn) of the linear low-density polyethylene may be 28,000 or more. Often, the molecular weight distribution (Mw / Mn) of the linear low-density polyethylene may be 3.5 or less, and the number average molecular weight (Mn) of the linear low-density polyethylene may be 30,000 or more.

In the present specification, both Mw (weight average molecular weight) and Mn (number average molecular weight) are values obtained from polystyrene-equivalent values measured by gel permeation chromatography (GPC).

The linear low density polyethylene (LLDPE) is preferably a metallocene-catalyzed linear low density polyethylene (mLLDPE) in terms of increasing the above-mentioned effects.

When the sealant layer 13 of Easy Peel Type 2 contains linear low-density polyethylene, it may contain only linear low-density polyethylene (that is, it may be made of linear low-density polyethylene. ), And may contain linear low density polyethylene and other components (sometimes referred to as "other components" herein) (ie, linear low density polyethylene and It may consist of the other components).

The other component contained in the sealant layer 13 of Easy Peel Type 2 is not particularly limited and may be arbitrarily selected depending on the intended purpose. For example, it may be either a resin component or a non-resin component.

The other component, which is a resin component, is a resin other than linear low-density polyethylene.
The other component, which is a resin component, may be a homopolymer having only one constituent unit, or may be a copolymer having two or more constituent units.
More specific examples of the other component, which is a resin component, include low-density polyethylene (LDPE), terpene-based resin, and the like. The terpene resin is an additive for improving heat sealability at low temperatures.

Examples of the other component, which is a non-resin component, include additives known in the art.
Examples of the additive as a non-resin component include the same additives as those described above as those contained in the sealant layer 13 having no easy peeling property.

The other components contained in the sealant layer 13 of Easy Peel Type 2 may be only one kind, two or more kinds, and when there are two or more kinds, the combination and ratio thereof are the object. It can be selected arbitrarily according to.

When the sealant layer 13 of Easy Peel Type 2 contains linear low-density polyethylene and low-density polyethylene, [content of linear low-density polyethylene in the sealant layer 13 (parts by mass)]: [in the sealant layer 13]. The mass ratio of [content of low-density polyethylene (parts by mass)] is preferably 50:50 to 99: 1, more preferably 60:40 to 99: 1, and 80:20 to 99: It is more preferably 1.

When the sealant layer 13 of Easy Peel Type 2 contains linear low-density polyethylene, the ratio of the total content of the linear low-density polyethylene and the low-density polyethylene to the total mass of the sealant layer 13 in the sealant layer 13. Is preferably 30% by mass or more, and more preferably 50% by mass or more. When the ratio is at least the lower limit value, the heat seal strength is more stable, and the paper residue at the time of peeling of the sterilized paper is suppressed to a higher degree.
The upper limit of the ratio is not particularly limited, and the ratio may be 100% by mass or less.
When the sealant layer 13 does not contain low-density polyethylene, the content of the low-density polyethylene is set to 0 parts by mass here.

The multilayer film 1 provided with such an easy peel type 2 sealant layer 13 can be heat-sealed with sterilized paper particularly preferably at a temperature of, for example, 135 to 155 ° C.

The sealant layer 13 may be composed of one layer (single layer) or may be composed of two or more layers, regardless of whether or not the sealant layer 13 has an easy peeling property. When the sealant layer 13 is composed of a plurality of layers, the plurality of layers may be the same as or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

In the present specification, not only in the case of the sealant layer 13, "a plurality of layers may be the same or different from each other" means "all layers may be the same or all layers may be the same". It may be different, and only a part of the layers may be the same. ”Furthermore,“ a plurality of layers are different from each other ”means“ at least one of the constituent materials and the thickness of each layer is different from each other ”. Means that.

The thickness of the sealant layer 13 is preferably 3 to 100 μm, more preferably 4 to 80 μm, and preferably 5 to 60 μm, regardless of whether or not the sealant layer 13 has easy peeling properties. More preferred. When the thickness of the sealant layer 13 is at least the above lower limit value, the sealing strength of the sealant layer 13 is appropriately increased. When the thickness of the sealant layer 13 is not more than the upper limit value, it is possible to prevent the sealant layer 13 from becoming excessively thick. For example, when the sealant layer 13 has an easy peel property, the thickness of the sealant layer 13 is not more than the upper limit value, so that the easy peel property becomes higher.
Here, the "thickness of the sealant layer 13" means the thickness of the entire sealant layer 13, and for example, the thickness of the sealant layer 13 composed of a plurality of layers is the total of all the layers constituting the sealant layer 13. Means the thickness of.

<First protective layer>
The first protective layer 11 is a layer for protecting the structure of the multilayer film 1 such as suppressing the occurrence of pinholes in the multilayer film 1.

The first protective layer 11 is preferably a resin layer containing a resin.

Examples of the resin contained in the first protective layer 11 include polyamide, polyester, polyolefin, polyvinyl resin, and polycarbonate.

For example, the first protective layer 11 containing polyamide has higher strength, and damage in the first protective layer 11 is remarkably suppressed. Further, by providing such a first protective layer 11, the multilayer film 1 has a protective action on the layer on the sealant layer 13 side of the first protective layer 11 and the packaging object in the package described later. The protective effect is significantly increased. As described above, the first protective layer 11 which is a resin layer containing polyamide is preferable in that it has higher strength.

Examples of the polyamide include a polyamide obtained by polymerizing or copolymerizing a cyclic lactam (lactam having 3 or more ring members), an amino acid, or a nylon salt which is a reaction product of a diamine and a dicarboxylic acid. Be done.

Examples of the cyclic lactam include ε-caprolactam, ω-enantractam, ω-laurolactam, α-pyrrolidone, α-piperidone and the like.

Examples of the amino acid include 6-aminocaproic acid, 7-aminoheptanoic acid, 9-aminononanoic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid and the like.

Examples of the diamine forming the nylon salt include tetramethylenediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, undecamethylenediamine, dodecamethylenediamine, 2,2. Aliphatic amines such as 4-trimethylhexamethylenediamine and 2,4,4-trimethylhexamethylenediamine;
1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, isophorone diamine, piperazine, bis (4-aminocyclohexyl) methane, 2,2-bis- (4-aminocyclohexyl) propane, etc. Alicyclic diamine;
Examples thereof include aromatic diamines such as m-xylylenediamine and paraxylylenediamine.

Examples of the dicarboxylic acid forming the nylon salt include aliphatic dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sepatic acid, undecandic acid, and dodecandioic acid;
Hexahydroterephthalic acid, and alicyclic carboxylic acids such as hexahydroisophthalic acid;
Telephthalic acid, isophthalic acid, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1,7- Examples thereof include aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid and 2,7-naphthalenedicarboxylic acid.

More specifically, as the polyamide, for example, 4-nylon, 6-nylon, 7-nylon, 11-nylon, 12-nylon, 46-nylon, 66-nylon, 69-nylon, 610-nylon, 611. -Nylon, 612-Nylon, 6T-Nylon, 6I Nylon, Copolymer of 6-Nylon and 66-Nylon (Nylon 6/66), Copolymer of 6-Nylon and 610-Nylon, 6-Nylon and 611-Nylon Copolymer, 6-nylon and 12-nylon copolymer (nylon 6/12), 6-nylon and 612 nylon copolymer, 6-nylon and 6T-nylon copolymer, 6-nylon and 6I-nylon Copolymers, 610-nylon copolymers of 6-nylon and 66-nylon, 12-nylon copolymers of 6-nylon and 66-nylon (nylon 6/66/12), 6-nylon and 66-nylon and 612- Copolymer with Nylon, Copolymer with 66-Nylon and 6T-Nylon, Copolymer with 66-Nylon and 6I-Nylon, Copolymer with 6T-Nylon and 6I-Nylon, Copolymer with 66-Nylon and 6T-Nylon and 6I-Nylon Examples thereof include a copolymer of.

The polyamide is 6-nylon, 12-nylon, 66-nylon, nylon 6/66, nylon 6/12 or nylon 6/66/12 in terms of heat resistance, mechanical strength, availability, and the like. Is preferable.

Examples of the polyester contained in the first protective layer 11 include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBN). And so on.

Examples of the polyolefin contained in the first protective layer 11 include polyethylene and polypropylene.

The polyvinyl-based resin contained in the first protective layer 11 is a resin having a structural unit derived from a monomer having a vinyl group (ethenyl group). Examples of the polyvinyl-based resin include polyvinyl chloride (PVC) and ethylene-vinyl alcohol copolymer (EVOH).

The resin contained in the first protective layer 11 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be arbitrary depending on the purpose. You can choose.

The first protective layer 11 preferably contains one or more selected from the group consisting of polyamide, polyester, polyolefin, polyvinyl resin and polycarbonate, and more preferably contains polyamide. Such a multilayer film 1 has higher pinhole resistance during heat molding.

The first protective layer 11 may contain the resin and other non-resin components.
Examples of the non-resin component include additives known in the art.
Examples of the additive which is a non-resin component include the same additives as those described above as those contained in the sealant layer 13.

The non-resin component contained in the first protective layer 11 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be determined according to the purpose. It can be selected arbitrarily.

In the first protective layer 11, the ratio of the content of the resin to the total mass of the first protective layer 11 is preferably 80% by mass or more, more preferably 90% by mass or more, for example, 95. It may be any of mass% or more, 97% by mass or more, and 99% by mass or more. When the ratio is at least the lower limit value, the effect obtained by using the resin in the first protective layer 11 becomes higher.
The upper limit of the ratio is not particularly limited, and the ratio may be 100% by mass or less.

When the first protective layer 11 contains a polyamide, the ratio of the content of the polyamide to the content of the resin in the first protective layer 11 is preferably 80% by mass or more, preferably 90% by mass or more. Is more preferable, and for example, it may be any of 95% by mass or more, 97% by mass or more, and 99% by mass or more. When the ratio is at least the lower limit value, the protective ability of the multilayer film 1 by the first protective layer 11 becomes higher.
The upper limit of the ratio is not particularly limited, and the ratio may be 100% by mass or less.

The first protective layer 11 may be composed of one layer (single layer) or may be composed of two or more layers. When the first protective layer 11 is composed of a plurality of layers, the plurality of layers may be the same as or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness _{X 11} of the first protective layer 11 is not particularly limited, but is preferably 1 to 100 [mu] m, more preferably from 3 to 50 [mu] m, for example, it may be 5 to 20 [mu] m. By thickness X ₁₁ of the first protective layer 11 is not less than the lower limit, the protection capability of the first protective layer 11 is further increased. By thickness X ₁₁ of the first protective layer 11 is equal to or less than the upper limit, it is avoided that the thickness of the first protective layer 11 becomes excessive.
Here, the "thickness of the first protective layer 11" means the thickness of the entire first protective layer 11, and for example, the thickness of the first protective layer 11 composed of a plurality of layers is the thickness of the first protective layer 11. Means the total thickness of all the layers that make up.

<Second protective layer>
Like the first protective layer 11, the second protective layer 12 is also a layer for protecting the structure of the multilayer film 1 such as suppressing the occurrence of pinholes in the multilayer film 1.

Examples of the constituent material (containing component) of the second protective layer 12 include the same constituent material (containing component) of the first protective layer 11 described above.
The content of the constituent material of the second protective layer 12 is the same as the content of the same constituent material of the first protective layer 11 described above.
Here, detailed description of the constituent materials of the second protective layer 12 and the content thereof will be omitted.

In the multilayer film 1, the first protective layer 11 and the second protective layer 12 may be the same as or different from each other. "The first protective layer and the second protective layer are different from each other" means that "at least one of the constituent materials and the thickness is different from each other when the first protective layer and the second protective layer are compared". For example, when the second protective layer 12 actually contains a component (constituent material) that the first protective layer 11 does not actually contain among the components (constituent materials) listed above, or actually. Even if the second protective layer 12 contains a component contained in the first protective layer 11, if the content (part by mass) thereof is different from that of the first protective layer 11, the first protective layer 11 and the second protective layer 11 and the second protective layer 11 The protective layers 12 are different from each other.

The second protective layer 12 may be composed of one layer (single layer) or may be composed of two or more layers. When the second protective layer 12 is composed of a plurality of layers, the plurality of layers may be the same as or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness _{X 12} of the second protective layer 12 is not particularly limited, but is preferably 1 to 100 [mu] m, more preferably from 1 to 50 [mu] m, for example, it may be 1 to 20 [mu] m. By thickness X ₁₂ of the second protective layer 12 is not less than the lower limit, the protection capability of the second protective layer 12 is further increased. By thickness X ₁₂ of the second protective layer 12 is less than the upper limit, it is avoided that the thickness of the second protective layer 12 becomes excessive.
Here, the "thickness of the second protective layer 12" means the thickness of the entire second protective layer 12, and for example, the thickness of the second protective layer 12 composed of a plurality of layers is the thickness of the second protective layer 12. Means the total thickness of all the layers that make up.

It is preferable that the first protective layer 11 and the second protective layer 12 contain the same constituent materials in terms of increasing the moldability of the multilayer film 1 at the time of heat molding.
For example, it is preferable that the first protective layer 11 and the second protective layer 12 both contain one or more selected from the group consisting of polyamide, polyester, polyolefin, polyvinyl resin and polycarbonate.
The first protective layer 11 and the second protective layer 12 both contain polyamide in terms of the higher moldability of the multilayer film 1 during heat molding and the higher protective ability of the multilayer film 1. It is more preferable to include it.

When the first protective layer 11 and the second protective layer 12 contain the same constituent materials, the contents (mass parts) of the constituent materials in the first protective layer 11 and the second protective layer 12 are the same as each other. It may be different from each other. By selecting any of these, the moldability of the multilayer film 1 at the time of heat molding may be improved.

<First base material layer>
The first base material layer 14 is a layer for imparting flexibility to the multilayer film 1.
The first base material layer 14 has an arbitrary configuration, and the multilayer film 1 does not have to include the first base material layer 14, but the multilayer film 1 includes the first base material layer 14, which is the same. Both flexibility and pinhole resistance are high.

The first base material layer 14 is preferably a resin layer containing a resin.

Examples of the resin contained in the first base material layer 14 include polyethylene-based resins.

Examples of the polyethylene-based resin include an ethylene homopolymer (that is, polyethylene) and an ethylene-based copolymer.

Examples of the ethylene homopolymer include low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE, for example, metallocene-catalyzed linear low-density polyethylene (mLLDPE), etc.), medium-density polyethylene (MDPE), and the like. High density polyethylene (HDPE) and the like can be mentioned.

The ethylene-based copolymer has a structural unit derived from ethylene and a structural unit derived from a monomer other than ethylene.
Examples of the ethylene-based copolymer include an ethylene-vinyl acetate copolymer (EVA resin), an ethylene-methyl acrylate copolymer (EMA resin), an ethylene-methyl methacrylate copolymer (EMMA resin), and ethylene. -Ethyl acrylate copolymer (EEA resin), ethylene-acrylate copolymer (EAA resin), ethylene-methacrylic acid copolymer (EMAA resin), ethylene-ethyl acrylate-maleic anhydride copolymer (E) -EA-MAH resin), ionomer resin (ION resin) and the like.
The ionomer resin is, for example, a resin in which a copolymer of ethylene and a small amount of acrylic acid or methacrylic acid has an ion cross-linking structure by salt formation of an acid portion thereof and metal ions. Can be mentioned.

The resin contained in the first base material layer 14 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof are arbitrary depending on the purpose. Can be selected.

The first base material layer 14 preferably contains polyethylene, more preferably linear low-density polyethylene, and may contain metallocene-catalyzed linear low-density polyethylene. Such a multilayer film 1 has higher flexibility and pinhole resistance.

The first base material layer 14 may contain the resin and other non-resin components.
Examples of the non-resin component include additives known in the art.
Examples of the additive which is a non-resin component include the same additives as those described above as those contained in the sealant layer 13.

The non-resin component contained in the first base material layer 14 may be only one kind, may be two or more kinds, and when there are two or more kinds, the combination and ratio thereof depend on the purpose. Can be selected arbitrarily.

In the first base material layer 14, the ratio of the content of the resin to the total mass of the first base material layer 14 is preferably 80% by mass or more, more preferably 90% by mass or more, for example. , 95% by mass or more, 97% by mass or more, and 99% by mass or more. When the ratio is at least the lower limit value, the effect obtained by using the resin in the first base material layer 14 becomes higher.
The upper limit of the ratio is not particularly limited, and the ratio may be 100% by mass or less.

When the first base material layer 14 contains the polyethylene-based resin, the ratio of the content of the polyethylene-based resin to the content of the resin in the first base material layer 14 is preferably 80% by mass or more. It is more preferably 90% by mass or more, and may be, for example, 95% by mass or more, 97% by mass or more, or 99% by mass or more. When the ratio is at least the lower limit value, the flexibility and pinhole resistance of the multilayer film 1 are further increased.
The upper limit of the ratio is not particularly limited, and the ratio may be 100% by mass or less.

The first base material layer 14 may be composed of one layer (single layer) or may be composed of two or more layers. When the first base material layer 14 is composed of a plurality of layers, the plurality of layers may be the same as or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

_{The thickness X 14} of the first base material layer 14 is not particularly limited, but is preferably 10 to 150 μm, more preferably 20 to 100 μm, and may be, for example, 25 to 60 μm. _{When the thickness X 14 of} the first base material layer 14 is at least the above lower limit value, the flexibility of the multilayer film 1 becomes higher. When the thickness X ₁₄ of the first base material layer 14 is equal to or less than the upper limit value, it is possible to prevent the thickness of the first base material layer 14 from becoming excessive.
Here, the "thickness of the first base material layer 14" means the thickness of the entire first base material layer 14, and for example, the thickness of the first base material layer 14 composed of a plurality of layers is the first. It means the total thickness of all the layers constituting the base material layer 14.

<Second base material layer>
Like the first base material layer 14, the second base material layer 15 is also a layer for imparting flexibility to the multilayer film 1.
The second base material layer 15 also has an arbitrary configuration, and the multilayer film 1 does not have to be provided with the second base material layer 15, but the multilayer film 1 is provided with the second base material layer 15. Both flexibility and pinhole resistance are high.

Examples of the constituent material (containing component) of the second base material layer 15 include the same constituent material (containing component) of the first base material layer 14 described above.
The content of the constituent material of the second base material layer 15 is the same as the content of the same constituent material of the first base material layer 14 described above.
Here, detailed description of the constituent materials of the second base material layer 15 and the content thereof will be omitted.

In the multilayer film 1, the first base material layer 14 and the second base material layer 15 may be the same as or different from each other. "The first base material layer and the second base material layer are different from each other" means that "at least one of the constituent materials and the thickness is different from each other when comparing the first base material layer and the second base material layer". means. For example, when the second base material layer 15 contains a component that is not actually contained in the first base material layer 14 among the components (constituent materials) listed above as those contained in the first base material layer 14. Even if the second base material layer 15 actually contains the component contained in the first base material layer 14, if the content (part by mass) is different from that of the first base material layer 14, the first base material layer 14 The base material layer 14 and the second base material layer 15 are different from each other.

The second base material layer 15 may be composed of one layer (single layer) or may be composed of two or more layers. When the second base material layer 15 is composed of a plurality of layers, the plurality of layers may be the same as or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

_{The thickness X 15} of the second base material layer 15 is not particularly limited, but is preferably 3 to 50 μm, more preferably 3 to 30 μm, and may be, for example, 3 to 20 μm. _{When the thickness X 15 of} the second base material layer 15 is at least the above lower limit value, the flexibility of the multilayer film 1 becomes higher. When the thickness X ₁₅ of the second base material layer 15 is equal to or less than the upper limit value, it is possible to prevent the thickness of the second base material layer 15 from becoming excessive.
Here, the "thickness of the second base material layer 15" means the thickness of the entire second base material layer 15, and for example, the thickness of the second base material layer 15 composed of a plurality of layers is the second. It means the total thickness of all the layers constituting the base material layer 15.

The first base material layer 14 and the second base material layer 15 may contain the same constituent materials. The multilayer film 1 provided with such a first base material layer 14 and a second base material layer 15 has higher flexibility and pinhole resistance.
For example, the first base material layer 14 and the second base material layer 15 both preferably contain polyethylene, more preferably both contain linear low-density polyethylene, and both contain metallocene-catalyzed linear low-density polyethylene. You may be.

When the first base material layer 14 and the second base material layer 15 contain the same constituent materials, the contents (mass parts) of the constituent materials in the first base material layer 14 and the second base material layer 15 are different from each other. They may be the same or different from each other. By selecting any of these, the flexibility of the multilayer film 1 may be increased.

As described above, in the multilayer film 1, the first base material layer 14 and the second base material layer 15 have an arbitrary configuration, but include at least the first base material layer 14 (that is, the first base material layer 14). It is preferable that both the base material layer 14 and the second base material layer 15 are provided, or the first base material layer 14 is provided and the second base material layer 15 is not provided).

<Adhesive layer>
The adhesive layer 16 is a multilayer film 1, in which two adjacent layers (here, a first protective layer 11 and a first base material layer 14, a first base material layer 14 and a second protective layer 12, and a second protective layer are used. It is a layer for adhering 12 and the second base material layer 15), and contains a component that exhibits adhesiveness.
The adhesive layer 16 has an arbitrary configuration, and the multilayer film 1 does not have to include a part or all of the adhesive layer 16 shown here, but the multilayer film 1 includes the adhesive layer 16. The structure is more stable.

The adhesive layer 16 is preferably a resin layer containing an adhesive resin.

Examples of the adhesive resin include polyolefin resins and the like.
The polyolefin-based resin is a resin having a structural unit derived from an olefin, and may be, for example, a modified polyolefin such as an acid-modified polyolefin having an acidic group.
Examples of the polyolefin-based resin include ethylene-based copolymers, propylene-based copolymers, butene-based copolymers, and modified products of these copolymers (in other words, modified copolymers).
The polyolefin-based resin is preferably a random copolymer, a graft copolymer, or a block copolymer from the viewpoint of further improving the adhesiveness.

Examples of the ethylene-based copolymer contained in the adhesive layer 16 include the ethylene-based copolymer described above as being contained in the first base material layer 14, and a modified product (modified copolymer) thereof.
Examples of the propylene-based copolymer contained in the adhesive layer 16 include a copolymer of propylene and a vinyl group-containing monomer, a modified product thereof (modified copolymer), and the like. More specific examples of such a propylene-based copolymer include maleic anhydride graft-modified linear low-density polypropylene and propylene-based thermoplastic elastomer.
Examples of the butene-based copolymer contained in the adhesive layer 16 include a copolymer of 1-butene and a vinyl group-containing monomer, a copolymer of 2-butene and a vinyl group-containing monomer, and modification of these copolymers. (Modified copolymer) and the like can be mentioned.

The adhesive layer 16 contains only one type of component (for example, the adhesive resin) that exhibits adhesiveness, or may be two or more types, and if there are two or more types, those components. The combination and ratio can be arbitrarily selected according to the purpose.

The adhesive layer 16 may contain other components in addition to the component exhibiting adhesiveness (for example, the adhesive resin) as long as the adhesiveness is not impaired.
Examples of the other components contained in the adhesive layer 16 include antioxidants and the like.

The other components contained in the adhesive layer 16 may be only one type, may be two or more types, and when there are two or more types, the combination and ratio thereof may be arbitrary depending on the purpose. You can choose.

In the adhesive layer 16, the ratio of the content of the component exhibiting adhesiveness to the total mass of the adhesive layer 16 (for example, the ratio of the content of the adhesive resin) is preferably 80% by mass or more, and is 90. It is more preferably mass% or more. When the ratio is equal to or higher than the lower limit value, the adhesiveness of the adhesive layer 16 becomes higher.
The upper limit of the ratio is not particularly limited, and the ratio may be 100% by mass or less.

The adhesive layer 16 may be composed of one layer (single layer) or may be composed of two or more layers. When the adhesive layer 16 is composed of a plurality of layers, the plurality of layers may be the same as or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.

The thickness of the adhesive layer 16 is not particularly limited, but is preferably 0.1 to 30 μm, more preferably 0.5 to 20 μm, and particularly preferably 1 to 10 μm.
When the thickness of the adhesive layer 16 is equal to or greater than the lower limit, the adhesive layer 16 has better adhesiveness. When the thickness of the adhesive layer 16 is not more than the upper limit value, it is possible to prevent the adhesive layer 16 from becoming excessively thick.
Here, the "thickness of the adhesive layer 16" means the thickness of the entire adhesive layer 16, and for example, the thickness of the adhesive layer 16 composed of a plurality of layers is the total of all the layers constituting the adhesive layer 16. Means the thickness of.

The adhesive layers 16 in FIG. 1, which constitute the multilayer film 1, may be all the same, may be all different, or may be partially the same. Here, the fact that the adhesive layers 16 are different means that at least one of the constituent materials and the thickness is different between the adhesive layers 16 to be compared.

<Other layers>
The multilayer film 1 includes a first protective layer 11, a second protective layer 12, a sealant layer 13, a first base material layer 14, and a second base material layer 15 within a range that does not impair the effects of the present invention. , And the adhesive layer 16, and other layers that do not correspond to any of the above may be provided.

The other layer is not particularly limited and may be arbitrarily selected depending on the intended purpose.
The arrangement position of the other layer is not particularly limited as long as the sealant layer 13 is the outermost layer of the multilayer film 1, and can be appropriately selected depending on the type thereof.
The other layer may be composed of one layer (single layer) or may be composed of two or more layers. When the other layer is composed of a plurality of layers, the plurality of layers may be the same as or different from each other, and the combination of the plurality of layers is not particularly limited as long as the effects of the present invention are not impaired.
The thickness of the other layer is not particularly limited and can be appropriately selected depending on the type thereof.

The multilayer film of the present embodiment is not limited to the multilayer film 1, and a part of the configuration of the multilayer film 1 may be changed, deleted, or added without departing from the gist of the present invention. ..

For example, in the multilayer film 1, the first protective layer 11 is the outermost layer, but in the multilayer film of the present embodiment, the first protective layer does not have to be the outermost layer. However, the first protective layer is preferably the outermost layer in terms of increasing the moldability of the multilayer film at the time of heat molding.

In the multilayer film 1, the sealant layer 13 and the second base material layer 15 are directly in contact with each other and laminated. However, in the multilayer film of the present embodiment, these are placed between the sealant layer and the second base material layer. One layer or two or more layers other than the above may be arranged, and the sealant layer and the second base material layer may be laminated via this layer.

The multilayer film of the present embodiment has high moldability at the time of heat molding, and the desired shape can be normally reproduced in the obtained molded product. The reason is presumed as follows.
That is, when comparing the outermost surface layer side of one of the conventional multilayer films with the outermost surface layer side of the other, the degree of shrinkage during heating tends to be different because the conventional multilayer films have layers having different characteristics. It is presumed that the multilayer film during heating is likely to warp. Therefore, when the multilayer film is heat-molded, the shape of the molded product is deformed due to such a difference in the degree of shrinkage, and the molded product having the desired shape cannot be obtained.

FIG. 2 is a cross-sectional view schematically showing an example of a conventional multilayer film. The multilayer film 7 shown here includes a sealant layer 73, a base material layer (sometimes referred to as a “comparative base material layer” in the present specification) 74, an adhesive layer 76, and a protective layer (in the present specification). (Sometimes referred to as a "comparative protective layer") 71 are laminated in this order in these thickness directions. In the multilayer film 7, one outermost layer is the sealant layer 73 and the other outermost layer is the protective layer 71, and the characteristics of these two layers are different. It may not be possible to obtain a molded product having a shape. Further, the base material layer 74 may also intensify such a decrease in moldability depending on the type thereof.
The base material layer 74 may be omitted.

On the other hand, the multilayer film of the present embodiment has a sealant layer on the outermost surface layer, a first protective layer on the outermost surface layer side opposite to the sealant layer, and further has the same characteristics as the first protective layer. The second protective layer is provided in a specific range area on the sealant layer side. In the multilayer film of the present embodiment, layers having different characteristics from each other, such as a sealant layer and a first protective layer, are arranged at positions separated from each other in the thickness direction in this way. Therefore, there is a possibility that a difference in the degree of shrinkage during heating is likely to occur, but the second protective layer arranged in the region on the sealant layer side makes it difficult for such a difference in the degree of shrinkage during heating to occur. It is presumed that it is. Therefore, it is presumed that the desired shape can be normally reproduced in the molded product obtained by heat molding the multilayer film of the present embodiment.

<< Manufacturing method of multilayer film >>
The multilayer film of the present embodiment is, for example, a feed block method in which a resin or a resin composition used as a material for forming each layer is melt-extruded using several extruders, or a coextrusion T-die method such as a multi-manifold method. , Air-cooled or water-cooled coextrusion inflation method or the like.

Further, in the multilayer film of the present embodiment, a resin, a resin composition or the like which is a material for forming any of the layers in the multilayer film is coated on the surface of another layer for forming the multilayer film, if necessary. It can also be produced by forming a laminated structure in a multilayer film and, if necessary, further laminating layers other than these so as to have a desired arrangement form.

Further, in the multilayer film of the present embodiment, two or more films for forming any two or more layers are separately prepared in advance, and these films are extruded by a dry laminating method using an adhesive. It can also be produced by laminating and laminating by any of a laminating method, a hot melt laminating method and a wet laminating method, and if necessary, further laminating layers other than these so as to have a desired arrangement form. At this time, as the adhesive, an adhesive capable of forming the adhesive layer may be used.

Further, in the multilayer film of the present embodiment, as described above, two or more films separately prepared in advance are laminated by laminating by a thermal (heat) laminating method or the like without using an adhesive. If necessary, it can also be manufactured by further laminating layers other than these so as to have a desired arrangement form.

When producing the multilayer film of the present embodiment, two or more of the methods for forming any layer (film) in the multilayer film described above may be combined.

Regardless of the production method, the resin composition used as a material for forming any layer in the multilayer film contains the desired component (constituent material) of the layer to be formed. The product may be produced by adjusting the type and content of the contained components so as to be contained in. For example, the ratio of the contents of the components that do not vaporize at room temperature in the resin composition is usually the same as the ratio of the contents of the components in the layer formed from the resin composition.

<< Packaging >>
The multilayer film of this embodiment is suitable for forming a package.
By using the multilayer film, the package provided with the multilayer film of the present embodiment can normally reproduce the desired shape.

The package of the present embodiment is not particularly limited as long as it includes the above-mentioned multilayer film of the present embodiment.
An example of the package of the present embodiment is a deep-drawn package.
The deep-drawn package is constructed by using a bottom material having a recess for forming a storage portion, storing the target object in the recess, and sealing the stored object with a thin lid material. It is a thing.
The deep-drawn package is suitable for use, for example, in packaging medical devices, foods, and the like.

FIG. 3 is a cross-sectional view schematically showing the package of the present embodiment.
In the figures after FIG. 3, the same components as those shown in the already explained figures are designated by the same reference numerals as in the case of the already explained figures, and detailed description thereof will be omitted.

The package 101 shown here includes a lid material 8 and a bottom material 10.
The bottom material 10 is obtained by deep drawing the multilayer film 1 shown in FIG. 1 (deep drawing molded body).
In the bottom material 10 in FIG. 3, the distinction between the layers in the multilayer film 1 constituting the bottom material 10 is omitted.

A recess 100 is formed in the bottom material 10.
One surface (sometimes referred to as "second surface" in the present specification) 10b of the region excluding the recess 100 of the bottom material 10 and one surface of the lid material 8 (in the present specification, "the second surface"). (Sometimes referred to as "two surfaces") 8b are both sealing surfaces and face each other.
The package 101 is composed of a seal of the lid material 8 and the bottom material 10. More specifically, the second surface 10b of the region excluding the recess 100 of the bottom material 10 and the second surface 8b of the lid material 8 are overlapped and sealed with each other in a region near their peripheral edges. As a result, in the region of the recess 100 of the bottom material 10, the storage portion 101a is formed between the second surface 10b of the bottom material 10 and the second surface 8b of the lid material 8. Then, the stored object 9 is stored in the storage portion 101a.
The second surface 10b of the bottom material 10 is the same as the second surface 13b of the sealant layer 13 in the multilayer film 1. The other surface (first surface) 10a of the bottom member 10 is the same as the first surface 11a of the first protective layer 11 in the multilayer film 1.

In FIG. 3, in the storage portion 101a of the package 101, some gaps can be seen between the stored object 9 and the bottom material 10 and between the stored object 9 and the lid material 8. The presence of these gaps is not essential in the package 101 in which the stored items 9 are stored.

The thickness of the bottom material 10 in the flat portion is the same as the thickness of the multilayer film 1 described above.

The lid material 8 can be appropriately selected depending on the use of the package 101.

For example, examples of the lid material 8 when the package 101 is used as a food package include those made of a single-layer or multi-layer resin film that can be used in a normal deep-drawing package.
The thickness of the lid material 8 made of the resin film may be, for example, 30 to 150 μm.

For example, examples of the lid material 8 when the package 101 is used as a medical package include polyethylene non-woven fabric, sterilized paper, and the like.
The thickness of the lid material 8 made of the polyethylene non-woven fabric or sterilized paper may be, for example, 50 to 500 μm.

The sterilized paper is mainly composed of paper, can be heat-sealed with the bottom material 10 (sealant layer 13), has air permeability, and prevents the permeation of bacteria through the paper (has antibacterial property). ), As long as sterilization treatment is possible, there is no particular limitation.

The sterilized paper preferably has small pores capable of exhibiting breathability and antibacterial properties.
More specifically, it is preferable that the sterilized paper is composed of 0.0001 to 20 dtex fibers and has a basis weight of 10 to 300 g / m ² .

The packaging of the present embodiment preferably includes, for example, the multilayer film according to the above-described embodiment of the present invention and sterile paper, and at least a part of the sealant layer in the multilayer film is said. Examples include a package that is heat-sealed on the surface of sterile paper. Here, as the "at least a part of the sealant layer" to be heat-sealed, for example, as described above, a region near the peripheral edge portion of the sealing surface of the sealant layer can be mentioned.

The package body of the present embodiment is not limited to the package body 101, and a part of the structure may be changed, deleted or added in the package body 101 within a range that does not deviate from the gist of the present invention. ..
For example, the package 101 uses the multilayer film 1 shown in FIG. 1, but the package of the present embodiment may use a multilayer film other than the multilayer film 1 shown in FIG. ..

<< Manufacturing method of packaging >>
In the packaging body of the present embodiment, for example, the lid material and the bottom material are superposed so as to form the storage portion in a state where the stored object to be packaged is stored in the recess in the bottom material. It can be manufactured by heat sealing.
When the lid material does not have air permeability, the inside of the area to be the accommodating portion may be evacuated and heat-sealed.

For example, when the lid material is sterilized paper, the lid material (sterilized paper) and the bottom material can be heat-sealed particularly preferably at a temperature of 135 to 155 ° C.

Hereinafter, the present invention will be described in more detail with reference to specific examples. However, the present invention is not limited to the examples shown below.
Examples 5 and 6 are reference examples.

[Example 1]
<< Manufacturing of multilayer film >>
Polyamide (PA) (“UBE Nylon 1022B” manufactured by Ube Industries, Ltd.) was prepared as the resin contained in the first protective layer and the second protective layer.
Further, as a resin contained in the adhesive layer, an adhesive polyethylene (PE) -based resin (“NF536” manufactured by Mitsui Chemicals, Inc.) was prepared.
Further, as the resin contained in the first base material layer, the second base material layer and the sealant layer, metallocene-catalyzed linear low-density polyethylene (mLLDPE) (1) (“5220G” manufactured by Dow Chemical Co., Ltd., molecular weight distribution (Mw). / Mn): 3.1, number average molecular weight (Mn): 3.08 × 10 ⁴ ) and metallocene-catalyzed linear low-density polyethylene (mLLDPE) (2) (Prime Polymer “SP3530”, melting point: 97 , 121 and 125 ° C., a molecular weight distribution (Mw / Mn): 7.7, number average molecular weight (Mn): and 1.37 × 10 ^4), were prepared.

Using the above-mentioned polyamide, adhesive polyethylene-based resin, and metallocene-catalyzed linear low-density polyethylene (1), the sealant layer (thickness 10 μm), the second base material layer (thickness 10 μm), and adhesion are performed by extrusion processing. Layer (thickness 7 μm), second protective layer (thickness 6 μm), adhesive layer (thickness 7 μm), first substrate layer (thickness 36 μm), adhesive layer (thickness 7 μm), and first protective layer (thickness 7 μm) A multilayer film (thickness 90 μm) having the structure shown in FIG. 1 was produced in which (thickness 7 μm) was laminated in this order in these thickness directions.

<< Evaluation of multilayer film >>
<Manufacturing of molded products>
A molded product was produced by forming a recess (pocket) in the multilayer film obtained above under the following molding conditions and performing deep drawing molding using a deep drawing molding machine (“R535” manufactured by Multiback Co., Ltd.).
[Molding condition]
Molding temperature: 108 ° C
Heating time: 1.5 seconds Molding time: 3.0 seconds Pressurization time: 0.4 seconds Mold size: Width 8.9 mm, length 270 mm, depth 6.99 mm, end R4.45 mm

<Evaluation of moldability of multilayer film>
Visually observing the recesses in the molded product obtained above, and based on the viewpoint of whether or not the shape and size are within the normal range expected from the mold used, the multilayer film is according to the following criteria. The moldability of the product was evaluated. The results are shown in Table 1.
[Evaluation criteria]
A: It is considered that the recesses are formed with high accuracy as expected from the usage mold, and there is no problem in storing the object to be packaged in the recesses.
B: The size of the recess is smaller than the size expected from the used mold, and the shape of the recess is slightly deformed, but it is considered that there is no problem in storing the object to be packaged in the recess.
C: It is considered that the size of the recess is significantly smaller than the size expected from the used mold, the shape of the recess is deformed, and there is a problem in storing the object to be packaged in the recess.

<Evaluation of the effect of suppressing foreign matter adhesion on the hot plate>
Using the multilayer film obtained above and GEA PowerPak ST 420, after cleaning the molding hot plate with alcohol, it was operated at a molding temperature of 108 ° C., a heating time of 9.9 seconds, and for 7 hours under the condition of no seal, and then heated. The surface of the plate was rubbed with a spatula, and the presence or absence of deposits on the hot plate was confirmed. The results are shown in Table 1.

[Example 2]
<< Manufacturing of multilayer film >>
The sealant layer (thickness 10 μm) and the second base material layer (thickness) were obtained in the same manner as in Example 1 except that the amounts of polyamide used to form the first protective layer and the second protective layer were changed. 10 μm), adhesive layer (7 μm thick), second protective layer (4 μm thick), adhesive layer (7 μm thick), first substrate layer (36 μm thick), adhesive layer (7 μm thick), and A multilayer film (thickness 90 μm) having the structure shown in FIG. 1 was produced in which the first protective layer (thickness 9 μm) was laminated in this order in these thickness directions.

<< Evaluation of multilayer film >>
The multilayer film obtained above was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 3]
<< Manufacturing of multilayer film >>
In the same manner as in Example 1, except that the amount of the metallocene-catalyzed linear low-density polyethylene (1) used for forming the sealant layer, the second base material layer and the first base material layer was changed. Sealant layer (thickness 11 μm), second base material layer (thickness 18 μm), adhesive layer (thickness 7 μm), second protective layer (thickness 6 μm), adhesive layer (thickness 7 μm), first base material layer A multilayer film having the structure shown in FIG. 1 in which (thickness 28 μm), an adhesive layer (thickness 7 μm), and a first protective layer (thickness 7 μm) are laminated in this order in these thickness directions. (Thickness 91 μm) was manufactured.

<< Evaluation of multilayer film >>
The multilayer film obtained above was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[Example 4]
<< Manufacturing of multilayer film >>
The point that the second base material layer was not formed, the point that the amount of the metallocene-catalyzed linear low-density polyethylene (1) used for forming the sealant layer and the first base material layer was changed, and the point that the adhesive layer was formed. The sealant layer (thickness 5 μm), the adhesive layer (thickness 5 μm), and the second protective layer (thickness 5 μm) were used in the same manner as in Example 1 except that the amount of the adhesive polyethylene resin used was changed. The thickness of the adhesive layer (thickness 7 μm), the first base material layer (thickness 54 μm), the adhesive layer (thickness 7 μm), and the first protective layer (thickness 7 μm) are in this order. A multilayer film (thickness 91 μm) constructed by being laminated in the direction was produced. This multilayer film has a structure in which the second base material layer is omitted in the multilayer film 1 shown in FIG.

<< Evaluation of multilayer film >>
The multilayer film obtained above was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Example 5]
<< Manufacturing of multilayer film >>
In order to form the first base material layer, the second base material layer and the sealant layer, a metallocene-catalyzed linear low-density polyethylene (2) was used instead of the metallocene-catalyzed linear low-density polyethylene (1). Except for the same method as in Example 3, the sealant layer (thickness 11 μm), the second base material layer (thickness 18 μm), the adhesive layer (thickness 7 μm), the second protective layer (thickness 6 μm), The adhesive layer (thickness 7 μm), the first base material layer (thickness 28 μm), the adhesive layer (thickness 7 μm), and the first protective layer (thickness 7 μm) are laminated in this order in these thickness directions. A constructed multilayer film (thickness 91 μm) having the structure shown in FIG. 1 was produced.

<< Evaluation of multilayer film >>
The multilayer film obtained above was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Example 6]
<< Manufacturing of multilayer film >>
In the same manner as in Example 1, except that the metallocene-catalyzed linear low-density polyethylene (2) was used instead of the metallocene-catalyzed linear low-density polyethylene (1) to form the sealant layer. , Sealant layer (thickness 10 μm), second base material layer (thickness 10 μm), adhesive layer (thickness 7 μm), second protective layer (thickness 6 μm), adhesive layer (thickness 7 μm), first base material A multilayer film having a structure shown in FIG. 1 in which a layer (thickness 36 μm), an adhesive layer (thickness 7 μm), and a first protective layer (thickness 7 μm) are laminated in this order in these thickness directions. (Thickness 90 μm) was manufactured.

<< Evaluation of multilayer film >>
The multilayer film obtained above was evaluated in the same manner as in Example 1. The results are shown in Table 2.

[Comparative Example 1]
<< Manufacturing of multilayer film >>
Except that the amount of polyamide used to form the first protective layer and the second protective layer was changed, and the amount of mLLDPE used to form the first base material layer and the second base material layer was changed. In the same manner as in Example 1, the sealant layer (thickness 10 μm), the second base material layer (thickness 27 μm), the adhesive layer (thickness 7 μm), the second protective layer (thickness 5 μm), and adhesion A layer (thickness 7 μm), a first base material layer (thickness 18 μm), an adhesive layer (thickness 7 μm), and a first protective layer (thickness 9 μm) are laminated in this order in these thickness directions. A multilayer film (thickness 90 μm) having the structure shown in FIG. 1 was produced.

<< Evaluation of multilayer film >>
The multilayer film obtained above was evaluated in the same manner as in Example 1. The results are shown in Table 3.

[Comparative Example 2]
<< Manufacturing of multilayer film >>
As the resin contained in the comparative protective layer, the same resin as the resin contained in the first protective layer and the second protective layer in the above-mentioned examples (polyamide, "UBE nylon 1022B" manufactured by Ube Industries, Ltd.) was prepared.
Further, as the resin contained in the adhesive layer, the same resin as the resin contained in the adhesive layer in the above-mentioned examples (adhesive polyethylene-based resin, “NF536” manufactured by Mitsui Chemicals, Inc.) was prepared.
Further, the resin contained in the comparative base material layer and the sealant layer is the same as the resin contained in the first base material layer, the second base material layer and the sealant layer in the above-mentioned examples (metallocene catalyst linear low density). Dense polyethylene (mLLDPE) (1)) was prepared.

By extruding each of the above resins, a sealant layer (thickness 10 μm), a comparative base material layer (thickness 55 μm), an adhesive layer (thickness 12 μm), and a comparative protective layer (thickness 14 μm) are formed. In this order, a multilayer film (thickness 91 μm) having a structure shown in FIG. 2 was produced by being laminated in these thickness directions. In the multilayer film 1 shown in FIG. 1, the second protective layer 12, the second base material layer 15, and the adhesive layer 16 adjacent to these two layers are omitted, and the layers other than the sealant layer 13 are omitted. Has a configuration in which the thickness of is changed.

<< Evaluation of multilayer film >>
The multilayer film obtained above was evaluated in the same manner as in Example 1. The results are shown in Table 4.

As is clear from the above results, the multilayer films of Examples 1 to 6 were excellent in moldability.
In the multilayer films of Examples 1 to 6, the distance of the second protective layer from the second surface of the sealant layer was 0.11T to 0.4T using the thickness T of the multilayer film.

On the other hand, the multilayer film of Comparative Example 1 was inferior in moldability.
In the multilayer film of Comparative Example 1, the distance of the second protective layer from the second surface of the sealant layer was 0.49 T using the thickness T of the multilayer film.

The multilayer film of Comparative Example 2 was also inferior in moldability.
Similar to the conventional multilayer film, the multilayer film of Comparative Example 2 had only one protective layer and a base material layer, and no improvement was observed in the moldability at the time of heat molding.

On the other hand, when the multilayer films of Examples 1 to 4 were used among Examples 1 to 6, foreign matter adhesion on the hot plate was suppressed during the molding. This is because, in Examples 1 to 4, the molecular weight distribution (Mw / Mn) of the metallocene-catalyzed linear low-density polyethylene used for forming the sealant layer was as narrow as 3.1, and the number average molecular weight (Mn) was 3. and 08 × 10 ^4, was presumed to be because the low molecular weight component is small.
As described above, the multilayer films of Examples 1 to 4 are particularly preferable because they have a high ability to prevent foreign matter from adhering to the equipment and prevent equipment contamination even if the continuous operation time of the equipment involved in molding is long. It had characteristics.

On the other hand, when the multilayer films of Examples 5 to 6 were used, foreign matter adhesion on the hot plate was not suppressed during the molding. In Examples 5 to 6, the molecular weight distribution (Mw / Mn) of the metallocene-catalyzed linear low-density polyethylene used for forming the sealant layer was as wide as 7.7, and the number average molecular weight (Mn) was 1.37 × 10. ⁴ , there were many low molecular weight components.

The present invention can be used for medical packaging, especially deep-drawn packaging.

1 ... Multilayer film 11 ... 1st protective layer 12 ... 2nd protective layer 12b ... 2nd surface of 2nd protective layer 13 ... Sealant layer 13b ... 2nd surface of sealant layer 14 ... 1st base material layer 15 ... 2nd base material layer 8 ... lid material 8b ... second surface of lid material 9 ... stored items 10 ... bottom material 10b ... Second surface of bottom material 101 ・ ・ ・ Package 101a ・ ・ ・ Storage part of package 100 ・ ・ ・ Recessed part of bottom material T ・ ・ ・ Thickness of multilayer film D ・ ・ ・ Second surface of second protective layer And the distance between the second surface of the sealant layer 13 and the second surface of the sealant layer 13 (distance of the second protective layer from the second surface of the sealant layer).
X ₁₁ ... Thickness of the first protective layer X ₁₂ ... Thickness of the second protective layer

Claims (4)

It ’s a multilayer film,
The multilayer film includes a sealant layer, a first protective layer, a second protective layer, an adhesive layer, and a first base material layer.
The sealant layer is one outermost layer of the multilayer film, and the first protective layer is the other outermost layer of the multilayer film.
The second protective layer is arranged between the sealant layer and the first protective layer without contacting the first protective layer.
In the multilayer film, the first protective layer, the adhesive layer, the first base material layer, the adhesive layer, and the second protective layer are laminated in this order in contact with each other.
The sealant layer contains a polyolefin resin and contains
The first base material layer contains a polyethylene-based resin and contains
Both the first protective layer and the second protective layer contain polyamide, and the first protective layer and the second protective layer both contain polyamide.
When the thickness of the multilayer film is T, the second protective layer is arranged at a distance of 0.1T to 0.45T from the surface of the sealant layer opposite to the first protective layer side. Ori,
The sealant layer contains linear low density polyethylene
A multilayer film having a molecular weight distribution (Mw / Mn) of 7.0 or less of the linear low-density polyethylene and a number average molecular weight (Mn) of 20000 or more of the linear low-density polyethylene. The multilayer film according to claim 1, wherein the molecular weight distribution (Mw / Mn) is 3.5 or less, and the number average molecular weight (Mn) of the linear low-density polyethylene is 30,000 or more. The multilayer film according to claim 1 or 2 , wherein the first protective layer and the second protective layer contain the same constituent materials. The multilayer film according to any one of claims 1 to 3 , wherein the first base material layer contains linear low-density polyethylene.

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