JP2002036433A - Stretch film for packaging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a well-balanced laminated stretch film for packaging food, excellent in packaging properties such as practical heal sealability, finish properties or the like while putting characteristics possessed by a film comprising a cyclic olefinic copolymer to practical use. SOLUTION: The stretch film for packaging food has at least a mixed resin layer based on three components of 20-50 wt.% of (A) a polypropylene resin, 20-60 wt.% of (B) the cyclic olefinic copolymer having a repeating unit originating from an α-olefin and a repeating unit originating from a cyclic olefin and having a glass transition temperature (Tg) of 30 deg.C or lower and 5-30 wt.% of (C) a copolymer of a vinyl aromatic compound and conjugated diene or a hydrogenated derivative thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stretch film suitably used for packaging foods and the like, and more particularly to a stretch film for packaging made of a material containing no chlorine.

[0002]

2. Description of the Related Art Conventionally, as a packaging film used for so-called pre-packaging, in which fruits and vegetables, meat, side dishes, etc. are placed on a lightweight tray and packaged with a transparent film, a polyvinyl chloride (PVC) -based film is mainly used. Have been used.
PVC-based packaging film has good packaging efficiency, beautiful packaging finish, and elastic recovery properties that immediately return to the original state even after pressing deformation such as pressing with a finger on the film after packaging. It is excellent and has good bottom sealing properties, so that the film does not peel off during transportation and display.
This is because it has a quality advantage recognized by both consumers. In recent years, however, hydrogen chloride gas is generated during incineration of polyvinyl chloride-based films and a large amount of plasticizer may be eluted. became.
For example, various types of packaging stretch films using a polyolefin resin have been proposed.
No. 1468 discloses a packaging film comprising a cyclic olefin copolymer having a repeating unit derived from an α-olefin and a repeating unit derived from a cyclic olefin, and having a glass transition temperature (Tg) of 30 ° C. or lower. Has been proposed. These packaging films have transparency, tear strength,
Although properties such as puncture strength, low-temperature heat-sealing properties, and elastic recovery properties are good, cyclic olefin copolymers have low melting points and a narrow heat-sealing temperature range. In addition, since a single film has a high rubber elasticity, there is a problem that cutting defects are likely to occur during packaging. In addition, simply mixing a high-melting-point olefin resin to solve these problems reduces the transparency and reduces the suitability for packaging, such as wrinkles during actual packaging, and poses a practical problem. I understand.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the object of the present invention is, of course, to have appropriate slip properties, self-adhesive properties, and anti-fog properties. A package with a well-balanced performance that has practical heat-sealing properties and packaging suitability such as finish suitability while taking advantage of properties such as transparency, tear strength and elastic recovery properties of a film made of a cyclic olefin copolymer. To provide a stretch film for use.

[0004]

In order to solve the above-mentioned problems, the stretch film for packaging according to the present invention comprises 20 to 50% by weight of the component (A), 20 to 60% by weight of the component (B) and (C) A) a packaging stretch film having at least one layer of a mixed resin having a component as a main component in the range of 5 to 30% by weight, wherein the component (A) of the mixed resin is a polypropylene resin; Component is a cyclic olefin copolymer having a repeating unit derived from an α-olefin and a repeating unit derived from a cyclic olefin, and having a glass transition temperature (Tg) of 30 ° C. or less,
The component (C) is a copolymer of a vinyl aromatic compound and a conjugated diene or a hydrogenated derivative thereof. In this case, the mixed resin further comprises (D) a petroleum resin as a fourth component in addition to the three components (A), (B) and (C), and 100 parts by weight of the three components. Can be mixed at a ratio of 40 parts by weight or less.
Further, the polypropylene resin as the component (A) constituting the mixed resin may be a propylene polymer having a crystal melting peak temperature of 120 ° C. or more. The polypropylene resin (A) constituting the mixed resin comprises a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-ethylene-butene-1 copolymer, and a reactor-type polypropylene-based elastomer. At least one polypropylene resin selected from the group can be used. Further, the repeating unit derived from the α-olefin of the component (B) constituting the mixed resin may be ethylene, and the repeating unit derived from the cyclic olefin may be a norbornene derivative. Further, the copolymer of the vinyl aromatic compound as the component (C) and the conjugated diene constituting the mixed resin,
It can be a styrene / conjugated diene-based random copolymer having a styrene content of 5 to 25% by weight and a vinyl bond content of the conjugated diene portion exceeding 50%. The above (D)
The component petroleum resins can be petroleum resins having a softening temperature of 100-150 ° C or hydrogenated derivatives thereof. Further, on at least one surface of the layer made of the mixed resin,
Melt flow rate (MFR) (JIS K7210, 1
90 ° C, load 21.18N) 0.2g / 10min ~ 5g
/ 10 minutes and a linear ethylene-vinyl acetate copolymer having a vinyl acetate content of 5 to 25% by weight and / or an α-olefin having 4 to 8 carbon atoms having an α-olefin content of 5 to 25% by weight. It is preferable to laminate a surface layer having an α-olefin copolymer as a main component.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The packaging stretch film of the present invention has at least one layer made of a mixed resin containing the following three components (A), (B) and (C) as main components. The mixing ratio of the component (A), the component (B) and the component (C) is such that the component (A) is 20 to 50% by weight and the component (B) is 2% by weight.
The component (C) is appropriately selected within the range of 0 to 60% by weight and the component (C) is within the range of 5 to 30% by weight. In the present invention, “having three components as main components” means that the three components are contained in the mixed resin at least 60% by weight or more, preferably 70% by weight or more. (A) Polypropylene resin: 20 to 50% by weight (B) Cyclic olefin having a repeating unit derived from an α-olefin and a repeating unit derived from a cyclic olefin, and having a glass transition temperature (Tg) of 30 ° C or lower. (C) Copolymer of vinyl aromatic compound and conjugated diene or hydrogenated derivative thereof: 5 to 30% by weight

If the content of the component (A) is less than 20% by weight and the content of the component (B) exceeds 60% by weight,
The heat resistance is not sufficiently improved, so that practical heat sealing properties cannot be obtained, and the cut-and-convey properties are liable to decrease. On the other hand, when the content of the component (A) exceeds 50% by weight and the content of the component (B) is less than 20% by weight, the flexibility of the resulting film is reduced, the elastic recovery is also reduced, and the packaging suitability is reduced. Is inferior. When the content of the component (C) is less than 5% by weight, the effect of improving the transparency is insufficient, and when it exceeds 30% by weight, the film becomes stiff at room temperature and becomes difficult to handle. In addition, the strength and cut transportability are liable to decrease, and the cost is undesirably increased.

In the present invention, the polypropylene resin as the component (A) is a homopolymer of propylene or a random copolymer or a block copolymer with another monomer copolymerizable with propylene. However, the three-dimensional structure is not particularly limited, and may be isotactic, atactic, syndiotactic, or a polymer having a mixed structure thereof. Examples of other copolymerizable monomers include ethylene, 1-butene, 1-hexene, 4-methyl-pentene-1, and 1-octene having 4 to 12 carbon atoms.
And diene such as divinylbenzene, 1,4-cyclohexadiene, dicyclopentadiene, cyclooctadiene and ethylidene norbornene. Of these, ethylene is preferred. Here, as the random copolymer, a propylene-ethylene random copolymer, a propylene-ethylene-butene-1 copolymer, and the like can be mentioned. As the block copolymer, a propylene-ethylene block copolymer or a reactor-type Specific examples of commercially available products include “NEWCON” (trade name, manufactured by Chisso Corporation) and “Catalloy” (trade name, manufactured by Sunrise Corporation, Montell SDC). Among them, those having a crystal melting peak temperature of 120 ° C. or more, preferably 130 ° C. or more are suitably used for the purpose of improving heat resistance and imparting practical heat sealability. The polypropylene resin as the component (A) can be used alone or in combination of two or more.

The component (B) is a cyclic olefin copolymer having a repeating unit derived from an α-olefin and a repeating unit derived from a cyclic olefin. However,
The glass transition temperature (Tg) needs to be 30 ° C. or lower, and is preferably in the range of −20 ° C. to + 20 ° C. If the glass transition temperature (Tg) exceeds 30 ° C., the tensile modulus increases, so that a large force is required at the time of stretch packaging, and the elasticity recoverability is reduced, resulting in poor packaging suitability. In addition, the glass transition temperature (T
g) is a value obtained as follows. That is, a viscoelastic spectrometer VES- manufactured by Iwamoto Seisakusho Co., Ltd.
Using F3, the vibration frequency was measured at 10 Hz and the temperature was raised at a rate of 1 ° C./min. The peak value of the loss elastic modulus (E ″) was obtained from the obtained data, and the temperature at that time was defined as the glass transition temperature (Tg).

The repeating unit derived from an α-olefin is not particularly limited, but includes a repeating unit represented by the following general formula [X].

Embedded image In the formula, Ra represents ^a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. Here, examples of the hydrocarbon group having 1 to 20 carbon atoms include a methyl group, an ethyl group, an isopropyl group, an isobutyl group, an n-butyl group, an n-hexyl group, an octyl group, and an octadecyl group. Α- which gives a repeating unit represented by the general formula [X]
Specific examples of the olefin include, for example, ethylene, propylene, 1-butene, 3-methyl-butene-1, 4-methyl-pentene-1, 1-hexene, 1-octene, decene, eicosene and the like. Among them, ethylene is preferably used.

The repeating unit derived from the cyclic olefin is not particularly limited, but includes a repeating unit represented by the following general formula [Y].

Embedded image However, in the formula, R ^{b to} R ^m each represent a hydrogen atom, a hydrocarbon group having 1 to 20 carbon atoms or a substituent containing an oxygen atom or a nitrogen atom, and R ^{b to} R ^m are the same or different from each other. R ^j or R ^k and R ¹ or R ^m may form a ring with each other. N represents an integer of 0 or more.

Here, as the hydrocarbon group having 1 to 20 carbon atoms, specifically, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, An alkyl group having 1 to 20 carbon atoms such as a hexyl group, an aryl group having 6 to 20 carbon atoms such as a phenyl group, a tolyl group, and a benzyl group, an alkylaryl group or an arylalkyl group, a methylidene group, an ethylidene group, a propylidene group, and the like. Examples thereof include an alkenyl group having 2 to 20 carbon atoms such as an alkylidene group having 1 to 20 carbon atoms, a vinyl group, and an allyl group. Where R ^b , R ^c ,
The alkylidene group is excluded from R ^f and R ^g , and when any of R ^d , R ^e , and R ^{h to} R ^m is an alkylidene group, the carbon atom to which it is bonded has another substituent. Not. Specific examples of the substituent containing an oxygen atom include, for example, a methoxy group, an ethoxy group, a propoxy group, an alkoxy group having 1 to 20 carbon atoms such as a phenoxy group, a methoxycarbonyl group, and a carbon atom having 1 to 1 carbon atoms such as an ethoxycarbonyl group.
And 20 alkoxycarbonyl groups. Specifically as a substituent containing a nitrogen atom, for example,
1 to 1 carbon atoms such as dimethylamino group and diethylamino group
20 alkylamino groups and cyano groups.

Specific examples of the cyclic olefin giving the repeating unit represented by the general formula [Y] include, for example, norbornene, 5-methylnorbornene, 5-ethylnorbornene, 5-propylnorbornene, 5,6-dimethylnorbornene, -Methylnorbornene, 7-methylnorbornene, 5,5,6-trimethylnorbornene, 5-
Phenylnorbornene, 5-benzylnorbornene, 5
-Ethylidene norbornene, 5-vinyl norbornene,
1,4,5,8-dimethano-1,2,3,4,4a,
5,8,8a-octahydronaphthalene, 2-methyl-
1,4,5,8-dimethano-1,2,3,4,4a,
5,8,8a-octahydronaphthalene, 2-ethyl-
1,4,5,8-dimethano-1,2,3,4,4a,
5,8,8a-octahydronaphthalene, 2,3-dimethyl-1,4,5,8-dimethano-1,2,3,4,4
a, 5,8,8a-octahydronaphthalene, 2-hexyl-1,4,5,8-dimethano-1,2,3,4,4
a, 5,8,8a-octahydronaphthalene, 2-ethylidene-1,4,5,8-dimethano-1,2,3,4
4a, 5,8,8a-octahydronaphthalene, 1,5
-Dimethyl-1,4,5,8-dimethano-1,2,3
4,4a, 5,8,8a-octahydronaphthalene, 2
-Cyclohexyl-1,4,5,8-dimetano-1,
2,3,4,4a, 5,8,8a-octahydronaphthalene, 2-isobutyl-1,4,5,8-dimethano-
1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 1,2-dihydrodicyclopentadiene, 5
Examples thereof include -methoxynorbornene, 5,6-dicarboxyl norbornene anhydrate, 5-dimethylaminonorbornene, and 5-cyanonorbornene, among which a norbornene derivative is preferably used.

In the present invention, the content of the repeating unit derived from the α-olefin component (for example, the repeating unit represented by the general formula [X]) constituting the cyclic olefin copolymer and the content derived from the cyclic olefin component. The ratio to the content of the repeating unit (the repeating unit represented by the general formula [Y]) (for example, [X]: [Y]) varies depending on the type and combination of the α-olefin and the cyclic olefin. Can not always be specified, but usually 80 to 9
9.9 mol%: 20 to 0.1 mol%, preferably 82 to 0.1 mol%
99.5 mol%: 18 to 0.5 mol%, particularly preferably 85 to 98 mol%: 15 to 2 mol%. When the content of the repeating unit represented by the general formula [X] is less than 80 mol%, the glass transition point and tensile modulus of the copolymer become high, and the elastic recovery of the film becomes insufficient. is there. On the other hand, when the content of the repeating unit derived from the α-olefin component exceeds 99.9 mol%, the effect of introducing the cyclic olefin component may be insufficient. Note that α-
Olefin composition and cyclic olefin composition are ¹³ CN
Measured by MR.

In the present invention, the cyclic olefin copolymer as the component (B) basically comprises the above-mentioned α-olefin component and the cyclic olefin component. As long as the purpose is not impaired, other copolymerizable unsaturated monomer components may be contained, if necessary, in addition to these two essential components.

The component (C) is a copolymer of a vinyl aromatic compound and a conjugated diene or a hydrogenated derivative thereof. Representative examples of the vinyl aromatic compound include styrene, but styrene homologs such as α-methylstyrene can also be used. As conjugated dienes,
Examples thereof include 1,3-butadiene, isoprene, and 1,3-pentadiene, and these can be used alone or as a mixture of two or more. However, if a double bond mainly containing a vinyl bond in the conjugated diene portion remains, thermal stability and weather resistance are extremely poor. To improve this, 80% or more, preferably 95% of the double bond is improved. % Is preferably used. Further, as the third component, a small amount of a component other than the vinyl aromatic compound and the conjugated diene may be contained. The ratio between the vinyl aromatic compound and the conjugated diene in such a copolymer is preferably in the range of 3/97 to 40/60 by weight. The bonding form of these copolymers (block, taper,
Is not particularly limited, but from the viewpoint of improving transparency, a copolymer having a styrene content of 5 to 25% by weight and a vinyl bond amount of the conjugated diene portion exceeding 50% is preferable. Is a hydrogenated derivative of a 65 to 90% styrene / conjugated diene random copolymer. For a detailed description of a hydrogenated derivative of a styrene / conjugated diene-based random copolymer that can be suitably used in the present invention and a method for producing the same, see JP-A-2-158643 and JP-A-2-30581.
4 and JP-A-3-72512. As a specific example of such a copolymer, a material having a structure of hydrogenated styrene butadiene rubber, which is abbreviated as HSBR, is available, and a commercial name “Dynalon 1320P” manufactured by JSR Corporation is available as a commercial product. It is.

It is preferable that the mixed resin layer is further mixed with a petroleum resin, which is the fourth component, for the purpose of further improving the suitability for packaging such as stiffness and cutability of the film and the transparency. However, the components (A), (B) and (C)
It is preferable to mix petroleum resins as the component (D) in a range of 40 parts by weight or less based on 100 parts by weight of the three components. If the content of the petroleum resin exceeds 40 parts by weight, the mechanical strength and low-temperature properties are reduced and the film is easily broken, or the petroleum resin bleeds over the surface over time, and the film is stored in a wound state. In such a case, problems such as blocking between the films are likely to occur. As the petroleum resins as the component (D), petroleum resins, terpene resins,
Coumarone-indene resin, rosin-based resin, hydrogenated derivatives thereof and the like can be mentioned. Examples of the petroleum resin include an alicyclic petroleum resin from cyclopentadiene or a dimer thereof, an aromatic petroleum resin from the C9 component, and the like. Examples of the terpene resin include a terpene resin from β-pinene and a terpene-phenol. Examples of the resin and the rosin-based resin include rosin resins such as gum rosin and wood rosin, and esterified rosin resins modified with glycerin and pentaerythritol. In the present invention, it is preferable to use a hydrogenated derivative of petroleum resins in terms of color tone, thermal stability, and compatibility. In addition, petroleum resins having various softening temperatures mainly depending on the molecular weight can be obtained, and those having a softening temperature of 100 to 150 ° C, preferably 110 to 140 ° C are suitably used.
To be more specific, the trade names “HIRETS” and “PETROZIN” manufactured by Mitsui Chemicals Co., Ltd., “ALCON” manufactured by Arakawa Chemical Industry Co., Ltd., “CLEARON” manufactured by Yashara Chemical Co., Ltd., Idemitsu Oil "Imarb" (trade name, manufactured by Kagaku Co., Ltd.) "Escolets" (trade name, manufactured by Tonex Corporation)
And other commercially available products.

In the present invention, other layers can be appropriately provided in addition to the layer made of the mixed resin. For example, it is preferable to laminate a layer made of another non-chlorine-based material as a surface layer on at least one surface of the layer made of the mixed resin, preferably on both surfaces. Other non-chlorine materials include non-chlorine materials such as polyolefin resins and flexible styrene-butadiene elastomers. By laminating such a surface layer, while adjusting the viscoelastic properties of the film, the moldability, appearance, flexibility and tensile properties of the film can be improved, and a suitable strength and elongation can be obtained, Also, the elongation at low temperatures can be improved.

As the material used for the surface layer, a polyolefin resin is preferable in terms of imparting surface characteristics and economy, and specifically, low-density polyethylene and linear ethylene-α-olefin copolymer It is recommended to use ethylene-vinyl acetate copolymer (EVA), ethylene-alkyl acrylate copolymer, ethylene-alkyl methacrylate copolymer, ethylene-acrylic acid copolymer and the like. Practically, EVA and / or linear ethylene-α
-Olefin copolymers can be suitably used.
However, when mixing, the mixing ratio can be determined as appropriate.

The EVA has a vinyl acetate content of 5-2.
5% by weight, preferably 10 to 20% by weight, and further has a melt flow rate (MFR) (JIS K7210, 1).
90 ° C, load 21.18N) 0.2g / 10min ~ 5g
/ 10 minutes is preferred. When the vinyl acetate content is less than 5% by weight, the resulting film is hard, and the flexibility and elastic recovery are reduced, and the surface tackiness is hardly exhibited. on the other hand,
If it exceeds 25% by weight, the surface tackiness is too strong and the unwinding property and appearance are liable to deteriorate.

The linear ethylene-α-olefin copolymer has an α-olefin content of 5 to 25% by weight, preferably 10 to 15% by weight, and further has an MFR (JIS).
K7210, 190 ° C, load 21.18N) is 0.2 ~
5 g / 10 min is preferred. If the content of α-olefin is less than 5% by weight, the obtained film is hard, and it is difficult to obtain uniform extensibility during stretch packaging. Therefore, the packaged film may be wrinkled, deformed or crushed. When the content exceeds 25% by weight, film forming becomes difficult or the unwinding property is apt to decrease. Here, as the α-olefin, 1-butene having 1 to 8 carbon atoms, 1-hexene, 4-methyl-pentene-1, 1-
Octene is preferred, and these can be used alone or in combination of two or more.

The above-mentioned EVA and linear ethylene-α-olefin copolymer are prepared by melt flow rate (MFR) (J
(ISK7210, 190 ° C, load 21.18N) is 0.
It is preferably from 2 g / 10 min to 5 g / 10 min. M
If the FR is less than 0.2 g / 10 min, the extrusion processability may decrease, while if it exceeds 5 g / 10 min, the film forming stability may decrease, and the thickness unevenness, the decrease in mechanical strength and the variation may occur. Is likely to occur, which is not preferable.

Generally, the thickness of the stretch film for packaging of the present invention is in the same range as the thickness of the stretch film for ordinary packaging, that is, about 8 to 30 μm, typically about 1 to 30 μm.
It is in the range of about 0 to 20 μm. When a laminated film is used, the ratio of the thickness of the layer made of the mixed resin described above to the total thickness, the thickness of the layer made of the mixed resin / the total thickness of the film = 0.2 to 0.9, Preferably 0.3 to
0.8, and the thickness of the layer made of the mixed resin is 5 to 20 μm.
m is preferable from the viewpoints of various properties and economy as a stretch film.

The stretch film for packaging of the present invention has a T
It is formed into a film by extrusion molding in which the material is melt-extruded from a die extruder or the like, or blow-molding in which the molten resin is blow-extruded from an annular (ring) die or the like. In the case of forming a laminated film, it is advantageous to co-extrude with a multilayer die using a plurality of extruders. In practice,
It is preferable that the material resin is melt-extruded from an annular (multi-layer) die to perform inflation molding, and the blow-up ratio (diameter of the expanded cylindrical film / diameter of the annular die) is preferably 4 or more, particularly 5 to 5. It is preferably in the range of 7. As a cooling method at that time, either a method of cooling from the outer surface side of the tubular film or a method of cooling from both the outer surface side and the inner surface side of the tubular film may be used. Further, the film obtained here may be stretched, for example, heated below the crystallization temperature of the resin, stretched 1.2 to 5 times in the longitudinal direction of the film using the speed difference between the nip rolls, Alternatively, the film may be biaxially stretched 1.2 to 5 times in both the vertical and horizontal directions.

Each layer constituting the stretch film for packaging of the present invention may include, for example, recycled resin generated from trimming loss or the like, without departing from the scope of the present invention.
For the purpose of further improving various physical properties such as antifogging property, antistatic property, sliding property, self-adhesiveness, etc., various additives can be appropriately compounded as needed. Examples of the various additives include an aliphatic alcohol having 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms, and 10 to 22 carbon atoms, preferably 1 carbon atom.
Examples thereof include aliphatic alcohol fatty acid esters which are compounds with 2 to 18 fatty acids, and specifically include monoglycerin oleate, diglycerin monooleate, polyglycerin oleate, glycerin triricinoleate, glycerin acetyl ricinoleate, and polyglycerin. Stearate,
Polyglycerin laurate, methyl acetyl ricinolate, ethyl acetyl ricinolate, butyl acetyl ricinolate, propylene glycol oleate, propylene glycol laurate, pentaerythritol oleate, polyethylene glycol oleate, polypropylene glycol oleate, sorbitan oleate, sorbitan laurate, polyethylene glycol Sorbitan oleate, polyethylene glycol sorbitan laurate and the like can be mentioned. Further, a polyalkylene ether polyol can be used, and specific examples include polyethylene glycol and polypropylene glycol. Furthermore, at least one compound selected from paraffinic oils and the like can be added. The amount of these additives is preferably 0.1 to 12 parts by weight, more preferably 1 to 8 parts by weight, based on 100 parts by weight of the resin component constituting each layer. The packaging target of the packaging stretch film of the present invention is not limited to food, and can be used for other purposes.

[0025]

The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention. In addition, various measured values and evaluations of the film displayed in this specification were performed as follows. However, the direction of flow of the film from the extruder is referred to as the vertical direction, and the direction perpendicular thereto is referred to as the horizontal direction.

1) Crystal melting peak temperature Differential scanning calorimeter manufactured by PerkinElmer, trade name "DS"
Using C-7, 10 mg of the sample was determined from a thermogram when the temperature was increased at a heating rate of 10 ° C./min according to JIS K7121. 2) Glass transition temperature (Tg) Using a viscoelastic spectrometer manufactured by Iwamoto Seisakusho Co., Ltd., trade name "VES-F3", measured at a vibration frequency of 10 Hz and a heating rate of 1 ° C./min. The peak value of the loss modulus (E ") was determined, and the temperature at that time was defined as the glass transition temperature (Tg). 3) Transparency (Haze) The obtained stretch film for packaging was measured with a haze meter according to ASTM D1003. 4) Packaging Suitability Using a stretch film for packaging having a width of 350 mm, an automatic packaging machine (trade name “ISIDA Wm” manufactured by Ishida Co., Ltd.)
ini MK-II ”), a tray made of expanded polystyrene (length 200 mm, width 130 mm, height 30 mm)
Was packaged and evaluated for transparency and packaging suitability. However, Table 2 shows the evaluation items of the suitability for packaging, and the evaluation methods and evaluation criteria.

Example 1 Component (A) Propylene-ethylene random copolymer (ethylene content: 4 mol%, crystal melting peak temperature: 147 ° C., 230
(MFR at 2.3 ° C .: 2.3 g / 10 min) (B) Component Ethylene-norbornene copolymer (Tg: 2 ° C., ethylene content: 94 mol%, crystal melting peak temperature: 99 ° C., 1
MFR at 90 ° C. and a load of 21.18 N: 1.5 g /
10 minutes) Component (C) Hydrogenated styrene-butadiene rubber (styrene content:
10%, the content of the vinyl binding portion of the conjugated diene portion: 7
8%, specific gravity: 0.89, MFR: 3.5 g / 10 min, T
g: -50 ° C, DYNARON132 manufactured by JSR Corporation
0P) The above three components (A), (B) and (C) are combined with (A) :( B) :( C) = 40% by weight: 40% by weight: 20% by weight. To prepare a mixed resin composition for an intermediate layer. Next, EVA (vinyl acetate content: 15% by weight, JIS K7210, 190
(° C, MFR under a load of 21.18 N: 2.0 g / 10 min)
To 100 parts by weight, 2.0 parts by weight of diglycerin monooleate as an antifogging agent was kneaded to prepare a resin composition for the front and back layers. The prepared mixed resin composition and the resin composition for the front and back layers are put into an annular three-layer die, and an annular die temperature of 190 ° C.
A total thickness of 15 μm by coextrusion inflation molding at a blow-up ratio of 5.5 (surface layer / intermediate layer / back layer = 2.5 μm)
/ 10 μm / 2.5 μm). About the obtained stretch film for packaging,
The transparency and packaging suitability were evaluated. The results are shown in Table 1.

(Comparative Example 1) In Example 1, an ethylene-norbornene copolymer was used, in which the resin composition for the intermediate layer was used as the component (B) in Example 1 instead of the mixed resin of three components. Except that the resin was used, the total thickness was 15 μm (2.5 μm / 10 μm / 2.
5 μm) was obtained. The obtained stretch film for packaging was evaluated for transparency and packaging suitability in the same manner as in Example 1. Table 1 shows the results.
Shown in

(Comparative Example 2) In Example 1, 50% by weight of a propylene-ethylene random copolymer in which the resin composition for an intermediate layer was used as the component (A) in Example 1 instead of the mixed resin of three components was used. (B) A total thickness of 15 μm (2.5 μm / 10 μm / 2.3 μm) was used in the same manner as in Example 1 except that a resin composition composed of two components, that is, 50% by weight of an ethylene-norbornene copolymer used as a component was used. 5 μm) was obtained. About the obtained stretch film for packaging, transparency was performed in the same manner as in Example 1,
The suitability for packaging was evaluated. The results are shown in Table 1.

Example 2 In Example 1, the mixing ratio of the component (A), the component (B) and the component (C) of the resin composition for an intermediate layer was determined by the following formula: component (A): component (B): C) Component =
Except that the weight ratio was changed to 50% by weight: 40% by weight: 10% by weight, a total thickness of 15 μm (2.5 μm /
(10 μm / 2.5 μm) was obtained. The obtained stretch film for packaging was evaluated for transparency and packaging suitability in the same manner as in Example 1.
The results are shown in Table 1.

Example 3 In Example 1, the mixing ratio of the component (A), the component (B) and the component (C) in the resin composition for an intermediate layer was determined by the following formula: component (A): component (B): C) Component =
30% by weight: 60% by weight: 10% by weight in the same manner as in Example 1 except that the total thickness was 15 μm (2.5 μm /
(10 μm / 2.5 μm) was obtained. The obtained stretch film for packaging was evaluated for transparency and packaging suitability in the same manner as in Example 1.
The results are shown in Table 1.

Example 4 In Example 1, the mixing ratio of the component (A), the component (B) and the component (C) of the resin composition for an intermediate layer was determined by the following: component (A): component (B): C) Component =
Except that the weight ratio was changed to 50% by weight: 20% by weight: 30% by weight, a total thickness of 15 μm (2.5 μm /
(10 μm / 2.5 μm) was obtained. The obtained stretch film for packaging was evaluated for transparency and packaging suitability in the same manner as in Example 1.
The results are shown in Table 1.

(Example 5) In Example 1, in addition to the components (A), (B) and (C), the resin composition for an intermediate layer was replaced by a fourth component (D): cyclopentadiene. Derivatives of Petroleum Resins (Softening Temperature 125 ° C)
Was used in the same manner as in Example 1 except that a mixed resin composition obtained by mixing 20 parts by weight with respect to 100 parts by weight of the three components (A) to (C) was used, and the total thickness was 15 μm (2.5 μm /
(10 μm / 2.5 μm) was obtained. The obtained stretch film for packaging was evaluated for transparency and packaging suitability in the same manner as in Example 1.
The results are shown in Table 1.

(Example 6) In Example 5, the thickness of each layer was changed to the surface layer / intermediate layer / back layer = 4.5 μm / 6 μm / 4.5.
except that the total thickness was 1 μm.
A 5 μm stretch film for packaging was obtained. The obtained stretch film for packaging was evaluated for transparency and packaging suitability in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 3) In Example 1, the mixing ratio of the three components (A), (B) and (C) was determined as follows: component (A): component (B): component (C) = Example 1 except that the ratio was changed to 10% by weight: 65% by weight: 25% by weight.
In the same manner as in the above, a stretch film for packaging having a total thickness of 15 μm was obtained. The obtained stretch film for packaging was evaluated for transparency and packaging suitability in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4 In Example 5, the mixing ratio of the fourth component petroleum resin: a hydrogenated derivative of cyclopentadiene-based petroleum resin (softening temperature: 125 ° C.) was determined by comparing the components (A) and (B) A stretch film for packaging having a total thickness of 15 μm was obtained in the same manner as in Example 5 except that the amount was 45 parts by weight with respect to 100 parts by weight of the mixed resin composition composed of the three components (C) and (C). The same evaluation as in Example 5 was attempted for the obtained stretch film for packaging, but the evaluation was not possible due to severe blocking between the films.

[0037]

[Table 1]

[0038]

[Table 2]

As is clear from Table 1, (A) of the present invention
Each of the stretch films for packaging of Examples 1 to 6 having the components, the components (B) and (C) in predetermined amounts, is all excellent in transparency and various properties (package suitability) as a stretch film. You can see that. On the other hand, the film of Comparative Example 1 was inferior in cut transportability and finish suitability, and poor in bottom sealability, because the mixed resin constituting the film was composed only of the component (B).
Further, the film of Comparative Example 2 was inferior in transparency because the mixed resin did not have the component (C), and had problems in cut transportability and finish suitability. The film of Comparative Example 3 is (A)
Since the amount of the component is less than 20% by weight and the amount of the component (B) is more than 60% by weight, the bottom sealability was poor, and there were also problems in cut transportability and finish suitability. In the film of Comparative Example 4, since the mixed resin contained 45% by weight of petroleum resins as the component (D), the film was blocked and could not be used for evaluation. That is, the films of Comparative Examples 1 to 4 did not satisfy any of the properties and were not well-balanced films. In addition, the stretch films for packaging of the present invention of Examples 1 to 6 have moderate self-adhesiveness,
It was also confirmed that it had tear strength, piercing strength, and elastic recovery.

[0040]

According to the present invention, practical heat sealability and finish suitability can be achieved while utilizing the properties such as transparency, tear strength, piercing strength, and elastic recovery of a film made of a cyclic olefin copolymer. Thus, a laminated stretch film for packaging having excellent performance in packaging and having well-balanced performance can be provided.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B65D 65/40 B65D 65/40 D C08F 210/00 C08F 210/00 210/02 210/02 232/00 232 / 00 232/08 232/08 C08J 5/18 CES C08J 5/18 CES C08L 23/02 C08L 23/02 23/10 23/10 23/12 23/12 23/14 23/14 23/16 23/16 45/00 45/00 57/02 57/02 // (C08L 23/02 (C08L 23/02 25:00) 25:00) (C08L 23/02 (C08L 23/02 47:00) 47:00) (C08L 23/10 (C08L 23/10 25:00) 25:00) (C08L 23/10 (C08L 23/10 47:00) 47:00) (C08L 23/12 (C08L 23/12 25:00) 25:00) (C08L 23/12 (C08L 23/12 47:00) 47:00) (C08L 23/14 (C08L 23/14 25:00) 25:00) (C08L 23/14 (C08L 23/14 47:00 47:00) (C08L 23/16 (C08L 23/16 25:00) 25:00) (C08L 23/16 (C08L 23/16 47:00) 47:00) (C08L 45/00 (C08L 45/00) 25:00) 25:00) (C08L 45/00 (C08L 45/00 47:00) 47:00) (C08L 57/02 (C08L 57/02 25:00) 25:00) (C08L 57/02 ( C08L 57/02 47:00) 47:00) (72) Inventor Masataka Noro 5-8, Mitsuya-cho, Nagahama-shi, Shiga Prefecture Mitsubishi Plastics Co., Ltd. Nagahama Plant F-term (reference) 3E086 AB02 AD17 BA02 BA04 BA15 BB51 CA01 4F071 AA10 AA12X AA14X AA15X AA20 AA20X AA21X AA22X AA39 AA39X AA84 AA85 AA86 AF16 AF20 AF28 AF30 AF56 AF58 AF59 AH04 BC01 4F100 AK02A AK07A AK08A AK12A AK28A AK62A AK62B AK63B AK64A AK68B AK73A AK80A AL01A AL03A AL05A AL06A AL09A AN02A BA01 BA02 GB15 JA04A JA05A YY00A YY00B 4J002 AC024 AC084 AF02Y BA00Y BA01Y BB05W BB12X BB13X BB14W BB14X BB15X BB16W BB17W BK00Y BL014 BL024 BP014 CE00Y FD100 GF00 GG02 4J100 AA02P AA03P AA04P AA09P AA15P AA16A AAP19A P AR09Q AR11Q AR32Q AS15Q AU21Q BA04Q BA05Q BA06Q BA15Q BA30Q BA31Q BA40Q BC43Q CA04 DA25 JA59

Claims (8)

[Claims] 1. The following (A) component: 20 to 50% by weight,
20 to 60% by weight of the component (B) and 5 to 30 of the component (C)
A stretch film for packaging, characterized by having at least one layer made of a mixed resin having a weight% as a main component. (A) a polypropylene-based resin (B) a cyclic olefin-based copolymer having a repeating unit derived from an α-olefin and a repeating unit derived from a cyclic olefin, and having a glass transition temperature (Tg) of 30 ° C. or lower (C ) Copolymer of vinyl aromatic compound and conjugated diene or hydrogenated derivative thereof 2. The mixed resin according to claim 1, wherein the component (A) is:
In addition to the three components (B) and (C), a fourth component (D): a petroleum resin is used as a fourth component.
The stretch film for packaging according to claim 1, wherein the mixing is performed at a ratio of 40 parts by weight or less with respect to 0 parts by weight. 3. The polypropylene resin as the component (A) constituting the mixed resin is a propylene polymer having a crystal melting peak temperature of 120 ° C. or higher. The stretch film for packaging according to claim 1. 4. The polypropylene resin (A) constituting the mixed resin is a propylene homopolymer, a propylene-ethylene random copolymer, a propylene-ethylene-butene-1 copolymer, and a reactor-type polypropylene-based resin. The stretch film for packaging according to any one of claims 1 to 3, wherein the stretch film is at least one kind of polypropylene resin selected from the group consisting of elastomers. 5. α of component (B) constituting said mixed resin
The repeating unit derived from an olefin is ethylene, and the repeating unit derived from a cyclic olefin is a norbornene-based derivative.
The stretch film for packaging according to any one of the above. 6. The copolymer of a vinyl aromatic compound as component (C) and a conjugated diene constituting the mixed resin has a styrene content of 5 to 25% by weight and a vinyl bond amount of a conjugated diene portion of 50. The stretch film for packaging according to any one of claims 1 to 5, which is a styrene / conjugated diene-based random copolymer in an amount of more than 10%. 7. The method according to claim 2, wherein the petroleum resin as the component (D) is a petroleum resin having a softening temperature of 100 to 150 ° C. or a hydrogenated derivative thereof. Stretch film for packaging. 8. At least one surface of the layer made of the mixed resin is provided with a melt flow rate (MFR) (JISK7).
210, 190 ° C., load 21.18 N) is 0.2 g / 1.
0 to 5 g / 10 minutes, and the vinyl acetate content is 5 minutes.
Surface layer having as a main component an ethylene-vinyl acetate copolymer having a content of from 5 to 25% by weight and / or a linear ethylene-α-olefin copolymer having a content of an α-olefin having 4 to 8 carbon atoms of 5 to 25% by weight. The stretch film for packaging according to any one of claims 1 to 7, wherein is laminated.