JP4721925B2 - Stretch shrink laminated film and manufacturing method thereof - Google Patents

Description

  The present invention relates to a stretch shrink film and a method for producing the same, and more specifically, mainly prepackages of various trays and containers containing fresh foods and processed foods, stretch shrink laminated films used for overlap shrink film applications, and It relates to the manufacturing method.

  As a shrink film having heat shrinkability used mainly for pre-packages of various trays and containers containing fresh foods and processed foods, and for an overlap shrink film, it may be abbreviated as polyvinyl chloride (hereinafter referred to as PVC). ) Based films and polyolefin (hereinafter sometimes abbreviated as PO) based films are known. This is because a shrink film made of PVC or PO-based material satisfies the user's requirements relatively widely, including the main required characteristics such as mechanical strength, transparency, shrinkage characteristics, and other practical characteristics. .

  However, among these PVC-based films, there is a concern about the problem of waste disposal, and thus a shrink film made of a material other than PVC has been desired. Therefore, in the above applications, at present, the shrink film made of almost PO system occupies the market.

  Next, the shrink film in the application is roughly divided into two according to the container used mainly. One is a high-shrink type shrink film that is mainly used for overlapping shrink packaging of containers with lids such as lunch boxes and side dishes at convenience stores, and the other is expanded polystyrene used mainly for stretch packaging. This is a stretch shrink film used in a packaging method in which a lidless tray made of a polypropylene material is used as a container and is stretch-wrapped, and then shrink-wrapped in order to develop wrinkle elimination and tight film tension.

  Here, in the packaging method using the high shrink type shrink film, a fusing seal type packaging machine called a horizontal pillow type is mainly used. In the present packaging method, first, a roll with a needle is passed through the film while it is being transported, and holes are formed in the film at a constant pitch. Next, a film is formed in a cylindrical shape so as to wrap the container, the film is pressure-bonded with a roller in the longitudinal direction at the bottom of the container and thermally sealed, and then the front and back of the container are fused and sealed. Thereafter, the film is passed through a shrink tunnel, and shrink wrapping is performed while air is released from the needle holes of the film formed earlier. In the packaging method, in order to obtain a tight packaging finish corresponding to containers of various shapes and sizes, physical properties such as a high shrinkage rate and a film that does not tear with a needle hole are required. For these reasons, various materials are combined in a specific amount to produce a multilayer structure, or a product is manufactured by a manufacturing method using a complex process such as crosslinking with an electron beam. It is difficult, and generally the manufacturing cost of the film is high (see, for example, Patent Documents 1 and 2).

  On the other hand, in the packaging method using stretch shrink, a tray used for normal stretch packaging is overlapped with a film, and the film is folded into the bottom of the tray and then shrink-wrapped. A wrapping machine in which a shrink tunnel is added to a subsequent process of a folding type wrapping machine called a horizontal pillow type or a push-up type is used. Here, the stretch wrapping is a wrapping method that expresses a wrapping finish such as wrinkle elimination and bottom sealability mainly due to viscoelastic properties such as a stress-strain curve and stress relaxation of the stretch film to be used. On the other hand, in packaging using stretch shrink film, a packaging method that develops packaging finish such as wrinkle elimination and bottom sealability after stretch packaging by passing the heat sealing process and shrink tunnel at the bottom after stretch packaging And the fact that a tight packaging finish can be manifested is a significant difference from ordinary stretch packaging.

  Among the packaging machines described above, the horizontal pillow method has a high packaging capacity (usually about 60 to 80 packs / minute), but the packaging line is long, so the efficiency of changeover operations such as size switching is poor. It is widely used in pack centers and food processing factories that are packed in large quantities and have relatively little changeover work, and products are arranged and displayed at each store after packaging. On the other hand, the push-up finger type has a low packaging capacity (usually about 25 to 50 packs / minute), but can accommodate a relatively large number of tray sizes with one size film (for example, a roll having a width of 350 mm), and is relatively compact. Because it requires less space, it has been introduced to pack centers and other places, but it is mainly used in supermarket in-stores (backyards).

  In this way, packaging of fresh products, etc. is broadly divided into those that are packaged at a pack center and delivered to each store, and those that are packaged at an in-store and displayed directly in the store. In terms of overall cost from the standpoint of efficiency, the in-store packaging ratio is decreasing, and the ratio of consolidation, large-volume, and high-speed packaging at pack centers is increasing. Here, in packaging at the pack center, about 2 to 4 packs of packed products are stacked, packed in a container, and delivered to each store by a cold car. For this reason, with normal stretch wrapping alone, film tearing or film sagging due to stacking may occur after delivery due to vibration during transportation or friction between products. There have been problems such as reducing the display effect and in some cases requiring repacking.

  In order to solve these problems, there is a tendency to increase the use of a stretch shrink film that can provide a tight film tension as compared with a stretch film. Since the packaging machine is the same as a normal stretch packaging machine, a shrink tunnel is added to the post-packaging process, and the tray shape does not vary. A high shrinkage rate is not required, and a sufficiently good packaging finish can be obtained with a relatively small shrinkage rate. However, the contents are often fresh foods, and heat shrinkage characteristics (hereinafter referred to as low temperature shrinkability in the present invention) at a relatively low temperature (usually about 80 ° C.) are required. A good stretch shrink film is desired.

  Next, the conventional shrink wrapping film manufacturing method is a tenter method in which a raw film or a raw tube is collected by once cooling and solidifying a melt-extruded resin, and then reheated and stretched. Tubular method is mainly used. This is considered to be because desired heat shrinkage characteristics and film physical properties can be imparted relatively easily by adjusting mainly the temperature at the time of reheating, the draw ratio and the draw speed.

  On the other hand, the method for producing a film for stretch packaging is a method in which a melt-extruded resin is extruded into a cylindrical shape from an annular die without cooling and solidifying once, and air is blown into this cylinder to expand the molten cylinder. The law is mainly adopted. This is probably because the inflation method generally has a relatively wide condition setting range than the tenter method or the tubular method, can be stably produced, and the cost of manufacturing equipment is also low. In general, in the inflation method, the raw material resin is heated to a temperature equal to or higher than the melting point (Tm), extruded from a circular die into a cylindrical shape, and blown into a molten cylinder to be inflated to form a film. Drawing is performed in the longitudinal direction by taking-up. However, at the time of stretching, since the resin is in a high temperature region and has a low elastic modulus and viscosity, it is a substantially unstretched film from the viewpoint of imparting heat-shrinkable strain only by inflation molding. Although heat shrinkability is exhibited, it is usually difficult to obtain a film having a sufficient orientation that exhibits a shrinkage rate (low temperature shrinkability) at a relatively low temperature (about 80 ° C.).

  Therefore, if a stretch shrink film having excellent low-temperature shrinkage can be produced even with an inflation molding machine having a general good productivity and low manufacturing equipment costs, it is an effective means for solving the above-mentioned problems relating to the production cost. It is thought that it becomes. Here, an ionomer resin is mentioned as one of the resins having high elastic modulus and high viscosity when melted. Examples of known literature related to stretch films, wrap films, and shrink (heat-shrinkable) films using ionomer resins include the following Patents 3 to 5.

  Patent Document 3 proposes a stretch film for food packaging in which a layer made of an ethylene / vinyl acetate copolymer having a vinyl acetate content of 5 to 40% by mass is laminated on both surfaces of a layer made of an ionomer resin. . Such a film has properties similar to those of a PVC film and is also excellent in automatic packaging suitability. Specifically, Suron A1650 (base polymer: ethylene / methacrylic acid copolymer, methacrylic acid content: 9% by mass, neutralized metal ion species: zinc, MFR: 1.5 g / 10 as an ionomer resin) This is the only example in which a three-layer stretch film having a blow-up ratio of 5 times and a thickness of each layer of 12.5 μm / 5 μm / 12.5 μm is obtained with a multilayer inflation molding apparatus. Has been. However, in this patent, the ionomer resin is mainly intended to improve the heat resistance during heat sealing, and in order to obtain the necessary physical properties as a stretch film, the thickness of the intermediate layer should not exceed the thickness of each of the front and back layers. Is necessary. For these reasons, the patent is not intended to exhibit shrinkage characteristics with an ionomer resin, and even if shrinkage characteristics are manifested, the intermediate layer has a low thickness ratio and is sufficiently low temperature shrinkable. Is not suitable for a stretch shrink film.

  Patent Document 4 is not intended to provide a non-halogen multi-layer wrap film that can be manufactured by high-speed processing, and has excellent optical properties, adhesion to a packaging material, and cutability during use, and a method for producing the same. An ethylene / unsaturated ester copolymer is formed on both sides of a layer composed of an ethylene / unsaturated carboxylic acid copolymer ionomer having a saturated carboxylic acid content of 3 to 20% by mass and a degree of neutralization by metal ions of 0.1 to 10%. A multilayer wrap film in which layers composed of the above are laminated and a method for producing the same by a coextrusion T-die film forming machine have been proposed. However, this patent mainly aims at high-speed molding in a T-die molding machine, and is not intended to express shrinkage characteristics with an ionomer resin.

  In Patent Document 5, (a) one or two outer layers of a material selected from the group consisting of polyethylene, polypropylene, propylene / ethylene copolymers and blends thereof, and (b) necessary to orient the materials of the outer layer. An ethylene / acid copolymer and related ionomer; an ethylene / acid / acrylate terpolymer and related ionomer; any of the above and up to about 50% ethylene vinyl acetate; A multilayer heat-shrinkable film comprising: a blend of an ethylene / ester copolymer and up to about 50% ethylene vinyl acetate; and a core layer of a material selected from the group consisting of combinations of the above materials, The multilayer heat shrinkable film and the multilayer, wherein the core layer has a thickness comprising about 50-95% of the total thickness of the heat shrinkable film A method for producing a shrinkable film, wherein a multilayer film comprising one or two outer layers and the core layer is at least the orientation temperature of the substance in the one or two outer layers but less than the melting point of the substance A method of stretching at a temperature has been proposed. Here, the patent mainly aims to obtain a multilayer heat-shrinkable film having a high shrinkage rate and a low shrinkage force (shrinkage stress), and from the gist of the invention, the melting point of the substance in the outer layer ≧ The relationship of stretching temperature ≧ orientation temperature of the substance in the outer layer (generally 110 ° C. or higher) ≧ melting point of the substance in the core layer holds. Moreover, it describes that the substance which has a low friction coefficient is preferable for an outer layer. Furthermore, as a method for orienting the film, a known method can be adopted, but a preferable method is described as a “bubble” method (tubular stretching method), and a specific method is also described. Examples are shown in Method 1 as a tubular stretching method and as Method 2 as a tenter stretching method. That is, these methods are methods in which a melt-extruded resin is once rapidly cooled and solidified, and then a raw film or a raw tube is collected and then reheated and stretched.

Japanese Examined Patent Publication No. 1-47311 Japanese Patent Publication No. 5-64589 Japanese Patent Laid-Open No. 54-24982 JP 2000-135760 A Japanese Patent Publication No. 3-80627

  The object of the present invention is to provide good low temperature shrinkability and tight film tension after shrinkage that can be produced even with an inflation molding machine that is generally inexpensive with low productivity and production equipment. An object of the present invention is to provide a stretch shrink laminated film having no breakage trouble and excellent packaging finish and a method for producing the same.

As a result of intensive studies, the present inventors specified an intermediate layer mainly composed of a mixed resin composition of an ionomer-based resin composition and a propylene-butene copolymer as both surface layers of an ethylene-based polymer. The present inventors have found that the above-mentioned problems can be solved by setting the thickness ratio, and have completed the present invention.
That is, the present invention
(1) A laminated film composed of at least three layers, wherein both surface layers are mainly composed of component (A), which is an ethylene polymer, and the intermediate layer is composed of (D) components 70 to 70 shown below. An ionomer resin composition ( B) component which is a mixed resin composition containing 30% by mass and (E) component 30 to 70% by mass, and a propylene-butene copolymer having a melting point of 90 ° C. or less (C ) The main component is a mixed resin composition with the component, and the thickness ratio of the intermediate layer to the entire film is 35 to 90%, and the vertical and horizontal directions when immersed in an oil bath at 80 ° C. for 10 seconds. Each of the thermal shrinkage ratios of the above is a stretch shrink laminated film characterized by being 20% or more.
(D) An ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 10 to 30% by mass and a degree of neutralization with metal ions of 30 to 80%.
(E) An ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 5 to 15% by mass and a melt flow rate (JIS K7210, 190 ° C., load: 21.18 N) of 0.2 to 5 g / 10 min. (2) Component (A) which is an ethylene polymer is low density polyethylene, linear low density polyethylene, linear ultra-low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer and ethylene -The stretch shrink laminated film according to (1), which is at least one ethylene polymer selected from methacrylic acid ester copolymers.
(3) Component (A) which is an ethylene polymer has a vinyl acetate content of 8 to 30% by mass, and a melt flow rate (JIS K7210, 190 ° C., load: 21.18 N) of 0.2 to 10 g / 10. The stretch shrink laminated film according to (1), wherein the stretch shrink laminated film is an ethylene-vinyl acetate copolymer.
(4) Melting | fusing point of (A) component which is an ethylene-type polymer is 65-100 degreeC, The stretch shrink laminated film as described in (1) characterized by the above-mentioned.
(5) The mixing ratio of the component (B) and the component (C) is 90 to 50% by mass of the component (B) and 10 to 50% by mass of the component (C). Stretch shrink laminated film.
(6) The melt-extruded resin is manufactured by the inflation method, which is a method of extruding into a cylindrical shape from an annular die without air-cooling and solidifying, and blowing air into the cylinder to expand the molten cylinder. The stretch shrink laminated film according to any one of (1) to (6).

  Another object of the present invention is achieved by producing the stretch shrink laminated film according to any one of the above (1) to (6) with an inflation molding machine.

  ADVANTAGE OF THE INVENTION According to this invention, the stretch shrink laminated | multilayer film excellent in the packaging finish in the favorable low temperature shrinkage | contraction property, the tension of the tight film after shrinkage | contraction, an automatic packaging machine, etc., and its manufacturing method can be provided.

The present invention will be described in detail below.
It should be noted that the upper limit and lower limit of the numerical range in the present invention are the same as those in the present invention as long as they have the same effects as those in the numerical range, even if they are slightly outside the numerical range characterized by the present invention. It is included in the equivalent range. In addition, the main component in the present invention is a component that is contained in the largest amount, and is usually a component that is 50% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more. .

  First, the stretch shrink laminated film of the present invention is a laminated film composed of at least three layers, both surface layers are mainly composed of component (A) which is an ethylene polymer, and the intermediate layer has a specific heat. The main component is a mixed resin composition of the component (B) which is an ionomer-based resin composition having characteristics and the component (C) which is a propylene-butene copolymer having a melting point of 90 ° C. or less. To do.

  Here, the component (A) that is an ethylene polymer that is a main component used in the both surface layers is low density polyethylene, linear low density polyethylene, linear ultra low density polyethylene, medium density polyethylene, high density polyethylene and Copolymers having ethylene as a main component, that is, ethylene and an α-olefin having 3 to 10 carbon atoms such as propylene, butene-1, pentene-1, hexene-1, heptene-1, octene-1; vinyl acetate 1 selected from vinyl esters such as vinyl propionate; unsaturated carboxylic acid esters such as methyl acrylate, ethyl acrylate, methyl methacrylate, and ethyl methacrylate; and unsaturated compounds such as conjugated and non-conjugated dienes And a copolymer or a multi-component copolymer with two or more comonomers, or a mixed composition thereof. That. The ethylene unit content of the ethylene polymer is usually more than 50% by mass.

  Among these ethylene polymer (A) components, low density polyethylene, linear low density polyethylene, linear ultra-low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer and At least one ethylene polymer selected from ethylene-methacrylic acid ester copolymers is preferred. Examples of the acrylate ester include methyl acrylate and ethyl acrylate. Examples of the methacrylic acid ester include methyl methacrylate and ethyl methacrylate.

  In the present invention, both surface layers have a film-forming stability during molding (for example, bubble stability in inflation molding), a balance between appropriate slip properties and surface adhesiveness of the resulting stretch shrink laminated film, or antifogging properties. In the component (A) which is the ethylene polymer, the vinyl acetate content is 8 to 30% by mass, because it bears the function of expressing surface characteristics such as surface characteristics and mechanical characteristics such as transparency and flexibility. An ethylene-vinyl acetate copolymer having a melt flow rate (hereinafter sometimes abbreviated as MFR) (JISK7210, 190 ° C., load: 21.18 N) of 0.2 to 10 g / 10 min has these characteristics. It is most preferable because it can be adjusted relatively easily including the material cost.

  If the vinyl acetate content is 8% by mass or more, the resulting film is not hard because the crystallinity is low, the flexibility and elastic recovery are good, and the transparency and low-temperature shrinkage of the entire film are impaired. This is preferable because it is easy to develop surface tackiness. On the other hand, if it is 30% by mass or less, heat resistance, film strength and the like are sufficiently secured, and the bleedability and surface adhesiveness of the antifogging agent to be added are not too strong, so the unwinding property and appearance of the film are good. Therefore, it is preferable. Accordingly, the vinyl acetate content is preferably 10 to 28% by mass, more preferably 12 to 25% by mass.

  Also, if the MFR is 0.2 g / 10 min or more, the extrusion processability is stable, while if it is 10 g / 10 min or less, the film forming stability is obtained even in the inflation molding, and the thickness unevenness and the mechanical strength are improved. This is preferable because reduction, variation and the like are reduced. Therefore, the MFR is preferably 0.5 to 8 g / 10 minutes, more preferably 1 to 5 g / 10 minutes.

  Furthermore, the melting point of the component (A), which is an ethylene polymer, is 65 to 65 from the balance between the above-mentioned surface characteristics and mechanical characteristics of both surface layers and the heat shrinkability characteristics of the resulting stretch shrink laminated film, particularly low temperature shrinkage. Most preferably, it is 100 ° C.

  If the melting point is 65 ° C. or higher, the heat resistance, film strength, etc. are less likely to be a practical problem, and the antifogging agent to be added is not too bleed or surface adhesive. It is preferable because the unwinding property and appearance are good. On the other hand, if it is 100 ° C. or lower, the resulting film is not hard because the crystallinity is low, the flexibility and elastic recovery are good, and the transparency and low-temperature shrinkage of the entire film are rarely impaired, Surface tackiness is also preferred because it is easy to develop. Therefore, the melting point is preferably 70 to 100 ° C, more preferably 75 to 98 ° C.

  The method for producing the ethylene polymer (A) component is not particularly limited, and a known polymerization method using a known olefin polymerization catalyst, for example, a multisite represented by a Ziegler-Natta type catalyst. Examples thereof include a slurry polymerization method, a solution polymerization method, a bulk polymerization method, a gas phase polymerization method and the like using a single site catalyst typified by a catalyst and a metallocene catalyst, and a bulk polymerization method using a radical initiator.

  Next, the ionomer resin comprises at least a part of an unsaturated carboxylic acid component of a copolymer comprising ethylene, an unsaturated carboxylic acid, and an optional other unsaturated compound as a minimum of a metal ion or an organic amine. It can be obtained by neutralizing either one. The ionomer resin can also be obtained by saponifying at least a part of an unsaturated carboxylic acid ester component of a copolymer comprising ethylene, an unsaturated carboxylic acid ester, and other unsaturated compounds as optional components. .

  In the copolymer containing ethylene and an unsaturated carboxylic acid as a raw material for the ionomer resin and other unsaturated compounds as optional components, the unsaturated carboxylic acid preferably has about 3 to 8 carbon atoms, specifically, Acrylic acid, methacrylic acid, fumaric acid, itaconic acid, maleic anhydride, monomethyl maleate, monoethyl maleate and the like are used. Among these, acrylic acid or methacrylic acid is preferably used. Further, other typical unsaturated compounds as optional components are unsaturated esters, and specific examples thereof include unsaturated esters of saturated carboxylic acids such as vinyl acetate, acrylic esters and methacrylic esters. Can be mentioned. In addition, these can be used individually by 1 type or in combination of 2 or more types.

As the neutralization component of ^{copolymer, Na +, K +, Li} +, Ca 2+, Mg 2+, Zn 2+, Cu 2+, Co 2+, Ni 2+, Mn 2+, 1 monovalent such as ^{Al 3+} To trivalent metal cations (hereinafter sometimes abbreviated as metal ions) or organic amines. In the present invention, sodium or zinc is preferably used. In addition, these can be used individually by 1 type or in combination of 2 or more types.

  In the ionomer resin, when the carboxyl group in the copolymer is neutralized with a metal cation or the like, the neutralized portion is ionized. As the degree of neutralization increases, the ionized portion aggregates due to the ionic bond force to form ionic crosslinks. The ionic crosslinks are aggregated by ionic bonds, and when they are subjected to a force greater than the ionic bond strength, the agglomerated portion is broken, but at a force smaller than the ionic bond force, a pseudo-crosslinked state is obtained. Therefore, the melt viscosity increases with the amount of neutralization, and this effect becomes greater near the melting point of the ionomer resin. Because of these effects, there is no excessive increase in extrusion performance, specifically melt viscosity, and ionic crosslinking remains in a pseudo-crosslinked state during stretching in the cooling process from a melted state such as inflation molding. It is considered that it is possible to impart a low temperature shrinkage property (low temperature shrinkability) suitable for a stretch shrink film.

  Next, (B) component which is an ionomer type resin composition used for this invention is demonstrated. In the ionomer resin composition, the ethylene content is 50 to 90% by mass, preferably 60 to 88%, the unsaturated carboxylic acid content is 10 to 30% by mass, preferably 12 to 20% by mass, and other unsaturated compounds are 0 to 90% by mass. Those having a polymerization composition of 40% by mass, preferably 0 to 20% by mass are suitably used. Further, the neutralization degree is preferably obtained by neutralizing 15 to 80%, preferably 20 to 60% of the amount of unsaturated carboxylic acid in the copolymer component with the metal cation. Here, if it is within the range of the polymerization composition and the degree of neutralization, the crystallinity of the ionomer resin composition is fixed to some extent, so that it is difficult to crystallize under cooling conditions during the molding process, and the transparency of the film is maintained. It is preferable because it becomes possible. At the same time, mainly due to the cohesive strength of ionic crosslinks, it is possible to impart good low temperature heat shrinkage properties (low temperature shrinkability) by stretching in the cooling process from a molten state such as inflation molding. Therefore, it is preferable. In addition, ionomer resin can be used alone or in combination of two or more. At this time, it is possible to combine ionomer resins having different metal ions.

  In the ionomer resin, when the carboxyl group in the copolymer is neutralized with a metal cation or the like, the neutralized portion is ionized. As the degree of neutralization increases, the ionized portion aggregates due to the ionic bond force to form ionic crosslinks. The ionic crosslinks are aggregated by ionic bonds, and when they are subjected to a force greater than the ionic bond strength, the aggregated portions are broken, but a pseudo-crosslinked state is obtained with a force smaller than the ionic bond strength. Therefore, the melt viscosity increases with the amount of neutralization, and this effect becomes greater near the melting point of the ionomer resin. Here, as long as it is within the range of the polymerization composition and the degree of neutralization, there is no increase in extrusion performance, specifically excessive melt viscosity, due to these actions, for example, in the cooling process from a molten state such as inflation molding. At the time of stretching, the ionic crosslinking remains in a pseudo-crosslinked state, so that it is considered possible to impart a low temperature heat shrinkage property (low temperature shrinkability) suitable for the stretch main land film.

  Regarding the degree of neutralization of the ionomer resin, the degree of neutralization can also be adjusted by blending an unneutralized copolymer with an ionomer resin having a high degree of neutralization. Specifically, for example, when the neutralization degree of an ionomer resin neutralized with monovalent metal ions and having a neutralization degree of 80% is set to 40%, neutralization is performed with an ionomer resin having a neutralization degree of 80%. This can be achieved by melt-kneading the uncopolymerized copolymer at a ratio of 50% by mass / 50% by mass.

The component (B) that is an ionomer resin composition is not particularly limited as long as the above-described characteristics are satisfied. In the present invention, the component (B) has a function of expressing good low-temperature shrinkage and mechanical properties such as tear resistance, so that (D) component 70 to 30% by mass shown below and (E) A mixed resin composition containing 30 to 70% by mass of component is suitably used, and more preferably, a mixed resin composition containing (D) 65 to 40% by mass of component (E) and 35 to 60% by mass of component (E). Particularly preferably, it is a mixed resin composition containing (D) component 60 to 50% by mass and (E) component 40 to 50% by mass.
(D) An ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 10 to 30% by mass and a degree of neutralization by metal ions of 30 to 80%. (E) An unsaturated carboxylic acid content of 5 to 15% by mass. An ethylene / unsaturated carboxylic acid copolymer having a melt flow rate (JIS K7210, 190 ° C., load: 21.18 N) of 0.2 to 5 g / 10 min.

  The component (D) has an ethylene content of 50 to 90% by mass, preferably 50 to 88% by mass, an unsaturated carboxylic acid content of 10 to 30% by mass, preferably 12 to 20% by mass, and other unsaturated compounds. Those having a polymerization composition of 0 to 40% by mass, preferably 0 to 20% are suitably used. Further, the neutralization degree is preferably obtained by neutralizing 30 to 80%, preferably 40 to 60%, of the amount of unsaturated carboxylic acid in the metal cationic copolymer component. Here, it is preferable that the component (D) is within the range of the polymerization composition and the degree of neutralization, since the crystallinity of the ionomer resin is reduced to some extent, so that the transparency of the film can be maintained. In addition, at the time of stretching in the cooling process from the melted state such as inflation molding, the ionic crosslinking remains in the pseudo-crosslinked state, so that the shrink property (low temperature shrinkability) suitable for the stretch shrink film is imparted. It is preferable because it becomes possible.

  The component (E) has an ethylene content of 50 to 90% by mass, preferably 60 to 88% by mass, an unsaturated carboxylic acid content of 5 to 15% by mass, preferably 6 to 12% by mass, and other unsaturated components. A compound having a polymerization composition of 0 to 45% by mass, preferably 0 to 20% is suitably used. Here, if it is the range of the said polymerization composition, since compatibility with ionomer resin is comparatively favorable and it becomes possible to maintain the transparency of a film, it is preferable. At the same time, it is preferable because mechanical properties such as tear resistance suitable for packaging by an automatic machine can be imparted.

  It is preferable that MFR (JIS K7210, 190 degreeC, load: 21.18N) of (B) component which is an ionomer type resin composition used for this invention is 0.2-20 g / 10min. Within such a range, back pressure or the like does not increase suddenly during extrusion molding, and it is possible to obtain inflation moldability such as bubble stability and mechanical properties suitable for a stretch shrink film. Therefore, the MFR is preferably 0.3 to 10 g / 10 minutes, more preferably 0.5 to 3 g / 10 minutes.

  The method for producing the component (B), which is an ionomer resin composition used in the present invention, is not particularly limited, and for example, a known production method disclosed in Japanese Patent Publication No. 39-6810 can be used. . Also, starting from a copolymer resin such as ethylene and acrylic acid or methacrylic acid that does not contain metal ions, acetylacetone metal complex, metal oxide, aliphatic acid metal salt is added after the necessary amount to introduce ionic crosslinking, An ionomer resin may be obtained at the time of molding. Copolymers such as ethylene and acrylic acid or methacrylic acid can be polymerized with a post metallocene catalyst.

  In the present invention, commercially available raw materials can also be used. As a specific product of ionomer resin, trade name “HIMILAN” of Mitsui-DuPont Polychemical Co., Ltd. may be mentioned. In addition, as specific products of copolymer resins such as ethylene and acrylic acid or methacrylic acid that do not contain metal ions, the product name “Nucrel” of Mitsui-DuPont Polychemical Co., Ltd. and the product of Nippon Polyethylene Co., Ltd. Names such as “Lex Pearl”.

  Next, (C) component which is a propylene-butene copolymer of this invention is demonstrated. The propylene-butene copolymer is a random copolymer containing propylene and at least one kind of butene selected from 1-butene, isobutene and 2-butene, and may further contain an α-olefin other than propylene and butene. A random copolymer of propylene and 1-butene or isobutene is preferable. The propylene content of the propylene / butene copolymer is preferably 50 to 90 mol%, more preferably 60 to 85 mol%. If it is in this range, it becomes a stretch shrink laminated film which is particularly excellent in low-temperature shrinkage.

  It is important that the propylene-butene copolymer as the component (C) has a melting point of 90 ° C. or lower. If the melting point is 90 ° C. or less, the crystallinity of the propylene-butene copolymer is reduced to some extent, and thus it is difficult to crystallize under cooling conditions during the molding step, and it is possible to maintain the transparency of the film. . At the same time, the crystallinity is reduced to some extent. For example, it can be deformed to a lower temperature by stretching in the cooling process from the melted state, such as inflation molding. Can be imparted, which is preferable.

  Moreover, it is preferable that MFR (JIS K7210, 190 degreeC, load: 21.18N) of (C) component which is a propylene-butene copolymer used for this invention is 0.2-20 g / 10min. Within such a range, a stretch shrink laminated film having excellent mixing property with the component (B) and excellent in low temperature shrinkage and flexibility is preferable.

  The production method of the component (C) that is the propylene-butene copolymer used in the present invention is not particularly limited, and a known production method can be used, and polymerization is performed using a Ziegler catalyst or a metallocene catalyst. It is also possible. In the present invention, a propylene-butene copolymer produced by a metallocene catalyst is more preferable than a Ziegler catalyst because the transparency is often good, the rigidity at normal temperature is high, and the melting point is low.

  Next, the intermediate layer used in the present invention will be described. It is important that the intermediate layer in the present invention is a mixed resin composition of the ionomer resin composition as the component (B) and the propylene-butene copolymer as the component (C). By making the intermediate layer a mixed resin composition of the component (C) and the component (D), it becomes possible to deform to a lower temperature, so that a good heat shrink property (low temperature shrinkability) at a low temperature can be imparted. It becomes possible.

  In the present invention, the intermediate layer has a function of expressing good low temperature shrinkage and mechanical properties such as tear resistance, so that the component (B) is 90 to 50% by mass and the component (C) is 10 to 50%. A mixed resin composition containing 5% by mass is preferably used, more preferably a mixed resin composition containing 90 to 60% by mass of component (B) and 10 to 40% by mass of component (C), particularly preferably. (B) It is preferable that it is a mixed resin composition containing 85-65 mass% of components, and (C) component 15-35 mass%.

  As described above, the stretch shrink laminated film of the present invention includes both surface layers mainly composed of the component (A) that is an ethylene polymer and the component (B) that is an ionomer resin composition having specific characteristics. , A laminated film composed of at least three layers having an intermediate layer mainly composed of a mixed resin composition with component (C) which is a propylene-butene copolymer having specific characteristics. Other layers (hereinafter sometimes abbreviated as “P layer”) may be introduced as needed to improve mechanical properties and interlayer adhesion as long as they do not exceed the gist. Here, the surface layer (hereinafter sometimes abbreviated as S layer) may have the same layer other than both surface layers, that is, an intermediate layer. Further, the intermediate layer (hereinafter sometimes abbreviated as “M layer”) may have at least one layer between both surface layers, and may have two or more layers. For example, a three-layer structure composed of (S layer) / (M layer) / (S layer), a four-layer structure composed of (S layer) / (P layer) / (M layer) / (S layer), (S layer) / (P layer) / (M layer) / (P layer) / (M layer) / (P layer) / (S layer), (S layer) / (M layer) / (P layer) / (M layer) A typical example is a five-layer structure including / (P layer) / (S layer), (S layer) / (M layer) / (S layer) / (M layer) / (S layer). In this case, the resin composition and thickness ratio of each layer may be the same or different.

  Here, the preferred laminated structure in the present invention is a three-layer structure composed of (S layer) / (M layer) / (S layer), and by adopting this layer structure, the object of the present invention is good. Low-temperature shrinkage and tight film tension after shrinking, packaging finished by automatic packaging machine, etc., and there is no breakage trouble when packaging with the above-mentioned automatic packaging machine called horizontal pillow type or push-up type. It is possible to obtain a stretch shrink laminated film excellent in properties (usually added to the intermediate layer) with good productivity and economy.

  Next, the stretch shrink laminated film of the present invention has a thickness ratio of 35 to 90% with respect to the thickness of the entire intermediate layer, and each of the longitudinal direction and the lateral direction when immersed in an oil bath at 80 ° C. for 10 seconds. It is important that the heat shrinkage rate is 20% or more.

  Here, as long as the thickness ratio of the intermediate layer to the entire film is within such a range, for example, as a film forming method, a stable production can be achieved even when a stretching process in a cooling process from a molten state such as inflation molding is used. It is preferable because film processability can be obtained, and heat shrinkage characteristics such as low temperature shrinkage suitable for stretch shrink films and mechanical properties such as transparency and flexibility can be imparted relatively easily including the material cost. From these facts, the thickness ratio is preferably 35 to 60%, more preferably 35 to 50%, when the stable film forming processability, flexibility and material cost are more important. In the case where the emphasis is placed on large low temperature shrinkability, tight film after shrinkage, and the like in the stretching process in the cooling process from such a molten state, it is preferably 60 to 90%, more preferably 65 to 85%. Here, when there are two or more intermediate layers in the laminated structure as described above, the thickness ratio may be calculated using the total thickness of all the intermediate layers. The overall thickness ratio of the stretch shrink laminated film of the present invention is not particularly limited, but is in the same range as the thickness of a normal stretch shrink film, that is, about 5 to 30 μm, typically 8 to It is in the range of about 20 μm.

  Further, in the present invention, although it varies depending on the size relationship between the width of the film used and the size of the tray, both the vertical and horizontal thermal shrinkage rates when immersed in an oil bath at 80 ° C. for 10 seconds are both 20 to 60. %, Preferably 25 to 50%, when shrink wrapping using the stretch shrink laminated film of the present invention, it is often possible to eliminate wrinkles after stretch wrapping regardless of the size and shape of the packaged object, Deformation of the tray, curling when the film folded on the bottom of the tray is heat-sealed, or deformation due to tight tightening due to natural shrinkage, etc. It is preferable because there is little to do.

  The above-mentioned heat shrinkage ratio is a predetermined range mainly by changing the thickness constitution of both surface layers and the intermediate layer, the stretching ratio, the blow-up ratio (bubble diameter / die diameter), and the temperature conditions such as the stretching temperature and the cooling condition. Can be adjusted. For example, when the thermal shrinkage rate is smaller than a desired value, the stretching ratio in the machine direction and / or the transverse direction is increased so as to increase the heat shrinkage strain at a lower temperature, or the amount of cooling blower in the outer surface cooling is increased. What is necessary is just to adjust suitably cooling efficiency, such as using UP and internal surface cooling together. On the other hand, when the heat shrinkage rate is larger than the desired value, the stretching ratio in the machine direction and / or the transverse direction is lowered so as to reduce the heat shrinkage strain at a lower temperature, or the cooling blower amount in the outer surface cooling. What is necessary is just to adjust cooling efficiency suitably, such as weakening DOWN of this and inner surface cooling.

  Next, in the intermediate layer of the stretch shrink laminate film of the present invention, an ionomer-based resin composition that is component (B) and a component (C) that is a propylene-butene copolymer having a melting point of 90 ° C. or less. Contains a mixed resin composition as a main component, but in addition to the components (B) and (C), the ethylene polymer as the component (A) described above is mixed within a range not exceeding the gist of the present invention. It doesn't matter. For example, when the main purpose is to add recycled resin generated from trimming loss, etc., or to improve the mechanical properties of the resulting stretch shrink laminated film as a whole, especially properties such as elastic modulus (rigidity) and tear strength, and to reduce material costs It becomes an effective means. The mixing mass ratio when mixing is (A) / ((B) + (C)) = 1-50 / 99-50, preferably 5-50 / 95-50, more preferably 10-45 /. 90-55.

  Here, as the component (A) that can be most suitably mixed, an ethylene-vinyl acetate copolymer having a vinyl acetate content of 10 to 25% by mass can be used. This is suitable for use as both surface layers, and has no practical problems including transparency, mechanical properties and material cost when recycled resin generated from trimming loss etc. is added. This is because it is also available stably.

  The stretch shrink laminated film of the present invention is necessary for the purpose of further adjusting and improving various physical properties such as anti-fogging property, antistatic property, slipperiness, self-adhesiveness, mechanical properties, etc. within the range not exceeding the gist of the present invention. Depending on the above, various additives and / or resins other than the components (A), (B), and (C) described above can be appropriately blended in the surface layer and / or the intermediate layer.

  Here, examples of the various additives include an antioxidant, an antifogging agent, an antistatic agent, a lubricant, and a nucleating agent, and are not particularly limited as long as the gist of the present invention is not exceeded. The additive suitably used in the present invention is a mixture of an aliphatic alcohol having 1 to 12 carbon atoms, preferably 1 to 6 carbons and an aliphatic alcohol having 10 to 22 carbon atoms, preferably 12 to 18 carbon atoms. Specific examples include aliphatic alcohol fatty esters such as monoglycerinolate, diglycerin monooleate, polyglycerin oleate, glyceryl trilysylate, glyceryl acetyl cinnolate, polyglyceryl stearate, polyglycerin laurate, methyl. Examples thereof include acetyl ricinolate, ethyl acetyl ricinolate, butyl acetyl ricinolate, propylene glycol oleate, propylene glycol laurate, pentaerythritol oleate, and polyethylene glycol sorbitan laurate. Furthermore, at least one compound selected from paraffinic oils can be added. A suitable addition amount of these additives is 0.1 to 12 parts by mass, preferably 2 to 8 parts by mass, more preferably 3 to 6 parts by mass, when the total of various resin components is 100 parts by mass. In the present invention, it is preferably added to at least the surface layer.

  Further, the resins other than the components (A), (B), and (C) are not particularly limited as long as they do not exceed the gist of the present invention. Examples thereof include plastic elastomers, various impact resistance improvers, compatibilizers, tackifying resins, and plasticizers. A suitable addition amount of these other resins is 0 to 20 parts by mass, preferably 0 to 15 parts by mass, more preferably 0 to 10 parts by mass, when the total of various resin components is 100 parts by mass. .

  Next, the manufacturing method of the stretch shrink laminated film of this invention is demonstrated. Various known production methods can be applied to the production method, and the production method is not particularly limited as long as it does not exceed the gist of the present invention. Examples of the film lamination method include a coextrusion lamination method, a lamination method, and a dry lamination method. Among these, in the present invention, a coextrusion lamination method in which melt bonding is performed is preferably used. Specifically, it is a method in which melt extrusion is performed using a plurality of extruders corresponding to the number of multilayers, and the molten resin is developed and laminated by a feed block, a multi-manifold or the like.

  As a method for imparting low-temperature shrinkage, which is one of the main objects of the present invention, a melt-extruded resin such as a commonly used tenter method or a tubular method is once cooled and solidified to be a raw film or an original film. A method of collecting the anti-tube and then reheating and stretching is also possible as appropriate. In the present invention, by adopting the above-mentioned laminated resin composition configuration, the melt-extruded resin is extruded into a cylindrical shape from an annular die without being once cooled and solidified, and air is blown into the cylinder. It has been found that a stretch-shrink laminated film excellent in low-temperature shrinkage can be obtained even by a so-called inflation method, which is a method of expanding a molten cylinder.

  The inflation method is a method in which the molten resin is taken from the annular die and the cooling effect works in the process of thinning, and the molecules constituting the film are oriented. The degree of orientation depends on the melt viscosity of the resin used and the solidification rate in the cooling process or It is considered that the change mainly depends on the difference in crystallization speed, blow-up ratio (bubble diameter / die diameter), bubble shape, and the like.

  In the present invention, when performing inflation molding, while adjusting the amount of cooling with a medium such as cold air, a fixed amount of air is introduced into the molten cylinder to adjust the amount of pressure, and the blow-up ratio is 3.5 or more, Preferably, 4 to 20, more preferably 5 to 15. Subsequently, by adjusting the film take-up speed, the deformation ratio of the resin extruded into a cylindrical shape from the annular ring is preferably adjusted to about 50 to 200 times, preferably 70 to 120 times for the entire film. Here, the deformation magnification is a value obtained by dividing the lip gap of the annular die by the thickness of the film. For example, when the lip gap of the annular die is 1 mm (1000 μm) and the thickness of the obtained film is 10 μm, the deformation magnification is 100 times. Further, when the lip gap of the annular die is 2 mm and the thickness of the obtained film is 10 μm, the deformation ratio is 200 times. The calculation of the deformation magnification is not affected by the blow-up ratio. As a cooling method at that time, either a method of cooling from the outer surface or inner surface side of the cylindrical film or a method of simultaneously cooling from both the outer surface side and the inner surface side of the cylindrical film may be adopted.

  The stretch shrink laminated film obtained by the above-described method is used for longitudinal stretching between heated rolls as necessary for adjusting the heat shrinkage rate, reducing the natural shrinkage rate and suppressing curling, etc. Heat treatment such as heat setting and aging can be performed. Further, for the purpose of imparting and promoting antifogging properties, antistatic properties, adhesiveness, etc., surface treatments such as corona discharge and aging, and surface treatments such as printing and coating can also be performed.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition, the various measured values and evaluation about the film displayed on this specification were performed as follows. Here, the flow direction from the extruder of the film is called the vertical direction, and the orthogonal direction is called the horizontal direction.

(1) Heat shrinkage rate The test piece which cut out the film from the obtained film to the strip shape of length 140mm * width 10mm each from the vertical direction and the horizontal direction, and wrote the mark line of 100 mm length in the middle is 80. The length between the marked lines after being immersed in an oil bath at 0 ° C. for 10 seconds and taken out was measured, and the shrinkage rate was determined in% from the length between the marked lines before and after immersion in the oil bath. In addition, the measurement was performed 10 times each, the average value was calculated, and the value rounded to the first decimal place was described.

(2) Suitability for automatic packaging machine Horizontal pillow type packaging machine (STN7500, manufactured by Omori Machine Co., Ltd.) + Shrink Tunnel (C-300 model attached to pillow packaging machine manufactured by Omori Machine Co., Ltd.), hot air setting 1000 pieces of ordinary foamed polystyrene tray (length 200mm, width 150mm, height 15mm) containing 200g of viscosity (thickness 10mm) with a temperature of 85 ° C and a transit time of 3 seconds at a speed of 70 packs / minute The suitability of an automatic packaging machine when packaged was evaluated according to the following criteria.
(◎): No breakage trouble occurred (0 times / 1,000 pieces)
(◯): 1 to 3 times of tearing or breaking trouble occurred, but no problem in practical use (×): 4 or more times of tearing or breaking trouble occurred, causing practical problems

(3) Packaging Finish Similar to (3) above, ordinary foamed polystyrene trays (length 200 mm, width 150 mm, height 15 mm) were packaged, and the resulting pack samples were evaluated according to the following criteria.
(◎): There is almost no wrinkles or sagging on the top surface of the tray, and there is sufficient film tension (○): There is almost no wrinkles or sagging on the top surface of the tray, and there is film tension (×): Any slack or no film tension

(4) Sag after time After the pack samples obtained in (3) above are stacked in three stages and left in a thermostatic bath at 5 ° C. for 10 hours, the state of the upper surface of the lowermost pack sample is as follows: Evaluation based on the criteria.
(◎): There is almost no sag on the top surface of the tray, and there is sufficient film tension (○): There is almost no sag on the top surface of the tray, and there is film tension (×): Sag is generated on the top surface of the tray, and the film Without tension

Example 1
As component (A) which is an ethylene polymer, ethylene-vinyl acetate copolymer (manufactured by Nippon Polyethylene: LV-440, vinyl acetate content: 15% by mass, MFR: 2.2 g / 10 min, melting point: 95 ° C.) A resin composition obtained by melting and kneading 5.0 parts by mass of diglycerin monooleate as an antifogging agent at an extrusion set temperature of 180 to 200 ° C. in 100 parts by mass (hereinafter abbreviated as A-1) is used as both surface layers. As the component (B) which is an ionomer-based resin composition, the ionomer (Mitsui / DuPont Polychemical: High Milan 1706, base polymer: ethylene / methacrylic acid copolymer, methacrylic acid content: 15% by mass as the component (D) , Neutralized metal ion species: zinc, neutralization degree: 59%, MFR: 0.7 g / 10 min, melting point: 88 ° C.) (hereinafter abbreviated as C-1) 60% by mass, (E) As an ethylene / unsaturated carboxylic acid copolymer, an ethylene / acrylic acid copolymer (manufactured by Nippon Polyethylene: Lexpearl A-210K, acrylic acid content: 7% by mass, MFR: 3.0 g / 10 min, melting point: 98 ° C) (hereinafter abbreviated as E-1) 40% by mass, (B) component 80% by mass, and (C) component propylene-butene copolymer (manufactured by Mitsui Chemicals: TAFMER) XM-7070, MFR = 3.3 g / 10 min, melting point: 81 ° C.) (hereinafter abbreviated as C-1) 20% by mass and melt-kneaded at a preset extrusion temperature of 180-200 ° C. as an intermediate layer , Respectively, were joined from separate extruders, co-extruded by blow molding with an annular three-layer die temperature of 185 ° C., a lip gap of 2.0 mm, and a blow-up ratio of 10.0, and a total thickness of 13 μm (thickness ratio: 1/6/1) ) Was obtained. The results of evaluating the obtained film are shown in Table 1.

(Example 2)
In Example 1, as the component (B) which is an ionomer resin composition, the ratio of D-1 as the component (D) and E-1 as the component (E) is expressed as a mass ratio of D-1 / E-1. = Stretch shrink laminated film was obtained in the same manner as in Example 1 except that 70% by mass / 30% by mass. The results of evaluating the obtained film are shown in Table 1.

(Example 3)
In Example 1, (B) component which is an ionomer-based resin composition is 100% by mass of D-1 as component (D), D-1 as component (B), and C as component (C) A stretch shrink laminated film was obtained in the same manner as in Example 1 except that the ratio of -1 was changed to D-1 / C-1 = 60% by mass / 40% by mass. The results of evaluating the obtained film are shown in Table 1.

Example 4
In Example 1, as the component (A) which is an ethylene polymer, an ethylene-vinyl acetate copolymer (manufactured by Mitsui DuPont Polychemical Co., Ltd .: Everflex EV-460, vinyl acetate content: 19% by mass, MFR: 2 A stretch shrink laminated film was obtained in the same manner as in Example 1 except that it was changed to 0.5 g / 10 min, melting point: 84 ° C.) (hereinafter abbreviated as A-2). The results of evaluating the obtained film are shown in Table 1.

(Comparative Example 1)
In Example 1, as the component (B) which is an ionomer-based resin composition, D-1 as the component (D) is 100% by mass, and only the component (B) is an intermediate layer. Similarly, a stretch shrink laminated film was obtained. The results of evaluating the obtained film are shown in Table 1.

(Comparative Example 2)
In Example 1, as (B) component which is an ionomer-type resin composition, it is the same as Example 1 except that E-1 used as the (E) component is 100% by mass and only the (B) component is used as the intermediate layer. Thus, a stretch shrink laminated film was obtained. The results of evaluating the obtained film are shown in Table 1.

(Comparative Example 3)
In Example 1, a stretch shrink laminated film was obtained in the same manner as in Example 1 except that the thickness ratio was set to surface layer / intermediate layer / surface layer = 2/1/2. The results of evaluating the obtained film are shown in Table 1.

From Table 1, the stretch shrink laminated film specified in the present invention has low temperature shrinkage and tight film tension after shrinkage, and there is no trouble of tearing or breaking during packaging in an automatic packaging machine, etc. Recognize. Moreover, it can confirm that it can manufacture also by inflation molding (Examples 1-4). In contrast, when the ionomer resin is used alone as the ionomer-based resin composition for the intermediate layer (Comparative Example 1), the packaging finish and the sag after the lapse of time are good, but it is practically used by the automatic packaging machine. When a large number of trays (about 1000 pieces) were packaged at a reasonable speed, many troubles of breaking occurred and there was a problem in practical use. When an ethylene / unsaturated carboxylic acid copolymer is used alone as the resin composition for the intermediate layer (Comparative Example 2), the suitability of the automatic packaging machine is good, but the packaging finish or pack sample is It can be confirmed that there is a problem with the slack after stacking. In addition, when the thickness ratio of the intermediate layer to the entire film is small and outside the specified range of the present invention (Comparative Example 3), the low-temperature shrinkability is poor, and wrinkles cannot be completely removed after shrinkage, resulting in a problem in packaging finish. It can be confirmed that there is.

Claims (7)

It is a laminated film composed of at least three layers, and both surface layers are mainly composed of component (A), which is an ethylene-based polymer, and the intermediate layer is 70 to 30% by mass of component (D) shown below. And an ionomer resin composition ( B) component which is a mixed resin composition containing 30 to 70% by mass of component (E), and a component (C) which is a propylene-butene copolymer having a melting point of 90 ° C. or less. And the thickness ratio of the intermediate layer to the entire film is 35 to 90%, and the heat in the vertical and horizontal directions when immersed in an oil bath at 80 ° C. for 10 seconds. Stretch shrink laminated film characterized in that both shrinkage rates are 20% or more.
(D) An ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 10 to 30% by mass and a degree of neutralization with metal ions of 30 to 80%.
(E) An ethylene / unsaturated carboxylic acid copolymer having an unsaturated carboxylic acid content of 5 to 15% by mass and a melt flow rate (JIS K7210, 190 ° C., load: 21.18 N) of 0.2 to 5 g / 10 min. Component (A) which is an ethylene polymer is low density polyethylene, linear low density polyethylene, linear ultra low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer, and ethylene-methacrylic acid. The stretch shrink laminated film according to claim 1, wherein the stretch shrink laminated film is at least one ethylene polymer selected from ester copolymers. Component (A) which is an ethylene polymer has an ethylene acetate content of 8 to 30% by mass and an ethylene melt flow rate (JIS K7210, 190 ° C., load: 21.18 N) of 0.2 to 10 g / 10 min. The stretch shrink laminated film according to claim 1, which is a vinyl acetate copolymer. The stretch shrink laminated film according to claim 1, wherein the melting point of the component (A) which is an ethylene polymer is 65 to 100 ° C. 2. The stretch shrink laminated film according to claim 1, wherein the mixing ratio of the component (B) and the component (C) is 90 to 50% by mass of the component (B) and 10 to 50% by mass of the component (C). . The melt-extruded resin is manufactured by an inflation method which is a method of extruding a cylindrical shape from an annular die without blowing and solidifying the resin, and blowing air into the cylinder to expand the molten cylinder. stretch shrink laminate film according to any one of claim 1-5. It manufactures with an inflation molding machine, The manufacturing method of the stretch shrink laminated film in any one of Claims 1-5 characterized by the above-mentioned.