JP5235494B2 - Laminated film, molded product using the film, heat shrinkable label, and container equipped with the label - Google Patents

Description

  The present invention provides a laminated film having excellent heat resistance and appearance, and hardly peeled even when processed at high temperature, a stretched film, a heat-shrinkable label, a molded product using the laminated film, and the heat-shrinkable property It relates to a container equipped with a label.

  Conventionally, various plastic materials such as polyethylene, polypropylene, polyester, polystyrene, polyethylene terephthalate, polyamide, polycarbonate, etc. are widely used as plastic materials for packaging materials, cards, containers, and others. When used, it is often difficult to obtain sufficient physical properties. For example, polylactic acid, which is a kind of polyester resin, has the disadvantages that it is fragile and inferior in impact resistance, and it is known to improve its physical properties by mixing it with a soft resin (patent) Reference 1).

  Further, as a technique for improving a defect that may occur in a film made of a single material, a film in which different materials are laminated is known. For example, Patent Document 2 discloses a shrink label in which an outer layer made of a polyester resin made of a specific monomer is laminated on both sides of an inner layer made of a polystyrene resin. This shrink label was provided to allow the inner layer made of polystyrene resin to intervene between the outer layer made of polyester resin, so that the shrinkage required for the shrink label and the label can be easily peeled off from the container. It has the feature of being excellent in cutting properties at perforations. Furthermore, this heat-shrinkable label is characterized by excellent solvent resistance and heat resistance because the inner layer made of polystyrene resin is covered with the outer layer made of polyester resin. However, when this heat-shrinkable label is attached to a container, there is a problem that the inner layer and the outer layer are peeled off by rubbing between films during transportation of the product after the label is attached, or by scratching with a human nail or the like. It has occurred.

Therefore, in such a laminated film, a method of forming an adhesive layer having adhesion between the outer layer and the inner layer is usually employed for the purpose of preventing peeling. For example, a heat-shrinkable multilayer film is disclosed in which an outer layer made of a polyester resin is laminated on an inner layer made of a polystyrene resin via an adhesive layer made of an olefin resin (see Patent Document 3). However, when the heat-shrinkable multilayer film of Patent Document 3 is attached to a container, there is a problem that the inner layer and the outer layer are peeled off in the heat shrinking step, and a sufficient peeling preventing effect and an excellent appearance cannot be obtained.
JP-A-9-111107 JP 2002-351332 A JP 61-41543 A

  As a recent trend, when a laminated film is used, for example, as a food packaging application, it is processed in a high-temperature atmosphere in a state where food is packaged with the laminated film for the purpose of boiling sterilization, heating, etc. There are many. Furthermore, for example, even when used as a heat-shrinkable film attached to a container such as a PET bottle or a metal can, it is necessary to pass through a heat-shrink process in the labeling process. Therefore, there is an increasing need to develop a laminated film having sufficient peel resistance and excellent appearance even when processed in a high temperature atmosphere in a laminated film with an adhesive layer interposed therebetween, but a satisfactory film has been obtained. Absent.

  The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a laminated film having excellent heat resistance and appearance, and hardly peeled off even when processed at a high temperature. is there.

  Another subject of the present invention is a molded article using the laminated film, a stretched film, a heat shrinkable film, a heat shrinkable label comprising the heat shrinkable film, and a container equipped with the heat shrinkable label. Is to provide.

An object of the present invention is to provide an outer layer composed of a resin composition mainly composed of at least one polyester-based resin, and an inner layer composed of a resin composition mainly composed of at least one selected from polyolefin-based resins and polystyrene-based resins. And an adhesive layer made of a resin composition mainly composed of an adhesive resin, disposed between the outer layer and the inner layer,
The adhesive resin is a mixed resin composition obtained by mixing at least two types of copolymers or resins selected from the group consisting of the following (a-1), (a-2) and (a-3).
(A-1) Copolymers of aromatic hydrocarbons and conjugated diene hydrocarbons, hydrogenated products of copolymers of aromatic vinyl hydrocarbons and conjugated diene hydrocarbons, or polar groups on these Introduced copolymer
(A-2) From ethylene monomer units and vinyl acetate, acrylic acid, (meth) acrylic acid, ethyl (meth) acrylate, methyl (meth) acrylic acid, maleic anhydride, and glycidyl (meth) acrylate A copolymer comprising one unit selected from the group consisting of:
(A-3) Modified polyolefin resin
The storage elastic modulus (E ′) in the temperature range from 50 ° C. to 100 ° C. under the conditions of the vibration frequency of 10 Hz and the strain of 0.1% of the resin composition constituting the adhesive layer is 10 MPa or more and 2000 MPa or less,
In the rectangular laminated film having a film take-up direction (MD) size of 165 mm and a perpendicular direction (TD) size of 235 mm, the outer layer surface on one end side of the take-up direction (MD) and the take-off direction (MD) ) Is sealed so that the inner layer surface or the outer layer surface on the other end side is parallel to the take-off direction (MD) to form an overlapping portion having a width of 2 to 7 mm on the laminated film and heat-treated at 90 ° C. When the temperature is returned to room temperature, the end surface of the outer layer sealed in the overlapping portion (MD) or the end surface of the outer layer and the adhesive layer (MD) and the direction of the adhesive layer and the inner layer (MD) ) Or the width of the gap between the end face of the inner layer in the take-off direction (MD) is within 5% of the overlap width of the overlap portion.

  Another subject of the present invention consists of a stretched film obtained by stretching the laminated film of the present invention in at least one direction, a heat-shrinkable film, a molded product obtained by molding these films, and a heat-shrinkable film. This is solved by a heat-shrinkable label and a container equipped with the label.

According to the present invention, a surface layer composed of a resin composition mainly composed of a polyester-based resin, an inner layer composed of a resin composition composed mainly of at least one selected from a polyolefin-based resin and a polystyrene-based resin, and a specific After cutting a laminated film having an adhesive layer made of the resin composition into a rectangular film piece of a predetermined size, an outer layer on one end side of the MD of the film piece and an inner layer or an outer layer on the other end side are predetermined. When the overlapped portion is formed by sealing with the width, and the heat treatment is returned to room temperature, the deviation width of the MD end face of the outer layer with respect to the overlapped width of the overlapped portion is within 5%. A laminated film that has an appearance and is difficult to peel even when processed at a high temperature is obtained.

  Moreover, if the laminated film of the present invention is used, a stretched film, a heat-shrinkable film, a molded article, a heat-shrinkable label, and the label that have excellent heat resistance and appearance and are difficult to peel even when processed at a high temperature. A container equipped with is obtained.

  In general, “film” refers to a thin flat product whose thickness is extremely small compared to the length and width and whose maximum thickness is arbitrarily limited, and is usually provided in the form of a roll. (Japanese Industrial Standard JISK6900), in general, the term “sheet” refers to a product that is thin by definition in the Japanese Industrial Standard (JIS), and usually has a thickness that is small instead of length and width. However, the boundary between the sheet and the film is not clear, and it is not necessary to distinguish both in terms of the wording in the present invention. Therefore, in the present invention, the term “film” includes “sheet”.

  Hereinafter, a laminated film, stretched film, heat-shrinkable film, heat-shrinkable label, molded product, container equipped with the heat-shrinkable label as an example of the embodiment of the present invention (hereinafter referred to as “laminated film of the present invention”, “The stretched film of the present invention”, “the heat-shrinkable film of the present invention”, “the heat-shrinkable label of the present invention”, “the molded product of the present invention”, and “the container of the present invention” may be omitted. ) Will be described in detail.

  In the present specification, “main component” is intended to allow other components to be included as long as the action and effect of the resin constituting each layer is not hindered. Further, this term does not limit the specific content, but it is 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably 90% by mass with respect to the total components of each layer. It is a component that occupies no less than 100% and no more than 100% by mass.

[Laminated film]
The laminated film of the present invention is disposed between an outer layer made of a resin composition mainly containing a polyester-based resin, an inner layer made of a resin composition mainly containing a thermoplastic resin, and the outer layer and the inner layer. And an adhesive layer made of a resin composition containing an adhesive resin as a main component.

<Outer layer>
The outer layer of the laminated film of the present invention is composed mainly of at least one polyester resin. The polyester-based resin provides rigidity and rupture resistance to the entire film and has a function of suppressing natural shrinkage while imparting low-temperature shrinkage in the case of a heat-shrinkable film. In the present invention, the type of the polyester resin is not particularly limited as long as it can provide the above functions. The polyester resin is not limited to a simple substance, and may be a mixed composition in which two or more polyester resins are blended. Suitable polyester resins include copolymer polyester resins derived from dicarboxylic acid components and diol components, polylactic acid resins obtained by polymerizing hydroxycarboxylic acids (hereinafter referred to as “PLA resins”), or these. Of the mixture.

  Examples of dicarboxylic acid components include terephthalic acid, isophthalic acid, 2-methylterephthalic acid, 4,4-stilbene dicarboxylic acid, 4,4-biphenyldicarboxylic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7 -Naphthalenedicarboxylic acid, bisbenzoic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4,4-diphenyl ether dicarboxylic acid, 4,4-diphenoxyethanedicarboxylic acid, 5-Na sulfoisophthalic acid, ethylene-bis -Aromatic dicarboxylic acids such as p-benzoic acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, azelaic acid, dodecanedioic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, etc. And aliphatic dicarboxylic acids.

  Examples of the diol component include diethylene glycol, triethylene glycol, polyethylene glycol, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2,2-dimethyl-1,3-propanediol, and trans-tetramethyl. -1,3-cyclobutanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, decamethylene glycol, cyclohexanediol, p-xylenediol, bisphenol A, tetrabromobisphenol A, tetrabromobisphenol A-bis (2-hydro Phenoxyethyl ether).

  The polyester resin used in the outer layer of the laminated film of the present invention is preferably a mixture in which at least one of a dicarboxylic acid component and a diol component is composed of two or more components. In the present specification, in the two or more components, the main component, that is, the component having the largest amount (mol%) is defined as the first component, and the component smaller than the first component is the component after the second component (that is, The second component and other components, specifically, the second component, the third component,..., The nth component). By making the dicarboxylic acid component and the diol component into such a mixture system, the crystallinity of the resulting polyester-based resin can be kept low, and even when blended in the resin constituting the outer layer, This is preferable because the progress of the conversion can be suppressed.

  A preferred diol component mixture is the group consisting of ethylene glycol as the first component, 1,4-butanediol, neopentyl glycol, diethylene glycol, polytetramethylene glycol, and 1,4-cyclohexanedimethanol as the second and subsequent components. Including at least one selected from the above, 1,4-cyclohexanedimethanol is preferred as the second component.

  Further, the preferred dicarboxylic acid component mixture includes at least one selected from the group consisting of terephthalic acid as the first component, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid, and adipic acid as the second and subsequent components. Among them, the second component is preferably isophthalic acid.

  The total amount of components after the second component is 10 mol% or more with respect to the total (200 mol%) of the total amount (100 mol%) of the dicarboxylic acid component and the total amount (100 mol%) of the diol component, It is preferably 20 mol% or more, and the upper limit is 40 mol%, preferably 35 mol%. When a component after the second component equal to or higher than the lower limit is included, a polyester resin composition having an appropriate crystallinity is obtained, and when a component after the second component equal to or lower than the upper limit is included In this case, the advantages of the first component can be utilized. For example, when ethylene glycol is used as the first component and 1,4-cyclohexanedimethanol is used as the second component, the content of 1,4-cyclohexanedimethanol is 100 mol of ethylene glycol and 1,4-cyclohexanedimethanol. % And the total amount (100 mol%) of the dicarboxylic acid component is in the range of 10 mol% to 40 mol%, preferably 25 mol% to 35 mol%. By using ethylene glycol and 1,4-cyclohexanedimethanol within such a content range, the resulting polyester has almost no crystallinity and breakage resistance is improved.

  The weight (mass) average molecular weight of the polyester resin is 30,000 or more, preferably 35,000 or more, and 80,000 or less, preferably 75,000 or less, more preferably 70,000 or less. . When the weight (mass) average molecular weight is 30,000 or more, an appropriate resin cohesive force can be obtained, and the film can be prevented from being insufficiently stretched or embrittled. On the other hand, if the weight (mass) average molecular weight is 80,000 or less, the melt viscosity can be lowered, which is preferable from the viewpoint of production and productivity improvement.

  The intrinsic viscosity (IV) of the polyester resin is 0.5 dl / g or more, preferably 0.6 dl / g or more, more preferably 0.7 dl / g or more, and 1.5 dl / g or less. Preferably it is 1.2 dl / g or less, More preferably, it is 1.0 dl / g or less. When the intrinsic viscosity (IV) is 0.5 dl / g or more, the deterioration of the film strength characteristics can be suppressed. On the other hand, if the intrinsic viscosity (IV) is 1.5 dl / g or less, breakage and the like accompanying an increase in stretching tension can be prevented.

  The refractive index of the polyester resin used as the main component in the outer layer is 1.56 or more, preferably 1.565 or more, and 1.58 or less, preferably 1.575 or less. If the refractive index of the polyester resin is within the above range, the inner layer after adding recycled resin generated from trimming loss or the like of the laminated film of the present invention to the inner layer (hereinafter referred to as “regeneration addition”) Can be adjusted to a predetermined range (range of 1.55 to 1.59).

  As said polyester-type resin, "PETG copolymerester 6663" (made by Eastman Chemical Co.), "SKYGREEN PETG" (made by SK Chemical Co., Ltd.) etc. are marketed, for example.

  When the polyester resin used as the outer layer of the laminated film of the present invention is a resin composition mainly composed of an aliphatic polyester resin, examples of the aliphatic polyester resin include polylactic acid (PLA), poly ( Butylene-succinate) (PBS), poly (ethylene-succinate) (PES), poly (butylene-succinate / adipate) (PBSA), polycaprolactone (PCL), poly (butylene-succinate- (δ-oxycaproate) ) (PBSC) and the like, but a PLA resin obtained by polymerizing hydroxycarboxylic acid can be preferably used.

  The type of PLA resin suitably used in the outer layer of the laminated film of the present invention is not particularly limited, but is a copolymer (poly (DL-lactic acid)) whose structural units are L-lactic acid and D-lactic acid, and these A mixture of copolymers can be suitably used.

  The copolymer ratio of D-lactic acid and L-lactic acid in the copolymer whose structural units are L-lactic acid and D-lactic acid is D-lactic acid / L-lactic acid = 99.5 / 0.5 to 85/15. Or D-lactic acid / L-lactic acid = 0.5 / 99.5 to 15/85, preferably D-lactic acid / L-lactic acid = 99/1 to 87/13 or D-lactic acid / L-lactic acid = 1/99 ~ 13/87. If the PLA resin has such a copolymerization ratio, the crystallinity becomes too low and the heat resistance is inferior, and there is no problem that the films are fused.

  Also, as a PLA resin, a blend of a plurality of PLA resins having different copolymerization ratios of L-lactic acid (hereinafter also referred to as L-form) and D-lactic acid (hereinafter also referred to as D-form). May be used. In this case, it is preferable to blend such that the average value of the copolymerization ratios of the L-form and D-form of a plurality of PLA resins falls within the above range.

  The PLA resin can be polymerized by employing various known methods such as a condensation polymerization method and a ring-opening polymerization method. For example, in the condensation polymerization method, PLA resin having an arbitrary composition can be obtained by directly dehydrating condensation polymerization of L-lactic acid or D-lactic acid, or a mixture thereof. In addition, in the ring-opening polymerization method (lactide method), a PLA system can be obtained by using an appropriate catalyst such as tin octylate while using lactide, which is a cyclic dimer of lactic acid, with a polymerization regulator as necessary. A resin is obtained. Lactide includes L-lactide, which is a dimer of L-lactic acid, D-lactide, which is a dimer of D-lactic acid, and DL-lactide composed of L-lactic acid and D-lactic acid, which are necessary. The PLA resin having an arbitrary composition and crystallinity can be obtained by mixing and polymerizing according to the above.

  In the present invention, for the purpose of improving heat resistance and the like, a range in which the essential properties of the PLA resin are not impaired, that is, a range in which the PLA resin component can be contained in an amount of 90% by mass or more based on the entire outer layer. If it is in, non-aliphatic dicarboxylic acid such as α-hydroxycarboxylic acid other than lactic acid, terephthalic acid, aliphatic dicarboxylic acid such as succinic acid, bisphenol A ethylene oxide adduct, etc. At least one selected from the group consisting of aliphatic diols and aliphatic diols such as ethylene glycol can be used. For the purpose of increasing the molecular weight, a small amount of a chain extender such as a diisocyanate compound, an epoxy compound, or an acid anhydride can be used.

  Examples of the α-hydroxycarboxylic acid other than lactic acid include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, and 2-hydroxy-3. -Bifunctional aliphatic hydroxycarboxylic acids such as methylbutyric acid, 2-methyllactic acid and 2-hydroxycaproic acid, and lactones such as caprolactone, butyrolactone and valerolactone.

  Examples of the aliphatic diol include ethylene glycol, 1,4-butanediol, 1,4-cyclohexanedimethanol and the like. Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid.

  The copolymerization ratio of the copolymer of lactic acid and α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid is lactic acid: α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid = 90: 10. The range is preferably 10:90, more preferably 80:20 to 20:80, and even more preferably 30:70 to 70:30. If the copolymerization ratio is within the above range, a film having a good balance of physical properties such as rigidity, transparency and impact resistance can be obtained.

  The PLA resin has a weight (mass) average molecular weight of 50,000 or more, preferably 75,000 or more, more preferably 100,000 or more, and 400,000 or less, preferably 300,000 or less. Preferably it is 250,000 or less. When the weight (mass) average molecular weight of the PLA resin is too small, practical physical properties such as mechanical properties and heat resistance are hardly expressed, and when it is too large, the melt viscosity becomes too high and the molding processability may be inferior.

  Representative examples of PLA resins preferably used in the present invention include “Lacia” manufactured by Mitsui Chemicals, “Nature Works” manufactured by Nature Works LLC, and the like.

  In the present invention, in order to improve impact resistance and cold resistance, an aliphatic polyester resin having a glass transition temperature (Tg) of 0 ° C. or lower, an aromatic polyester resin, etc. You may blend in the range below 70 mass parts with respect to a part. Examples of such aliphatic polyester resins include PLAs such as aliphatic polyesters obtained by condensing aliphatic diols and aliphatic dicarboxylic acids, aliphatic polyesters obtained by ring-opening polymerization of cyclic lactones, and synthetic aliphatic polyesters. Aliphatic polyester resin excluding the resin.

  Specifically, aliphatic polyester obtained by condensing aliphatic diol and aliphatic dicarboxylic acid is ethylene glycol, 1,4-butanediol, hexanediol, octanediol, cyclopentanediol, cyclohexanediol, 1,4 -Among aliphatic diols such as cyclohexanedimethanol, or anhydrides or derivatives thereof, and aliphatic dicarboxylic acids such as succinic acid, adipic acid, suberic acid, sebacic acid, dodecanedioic acid, or anhydrides or derivatives thereof. It can be obtained by selecting one or more of each from the above and performing condensation polymerization. At this time, a desired polymer can be obtained by adding an isocyanate compound or the like as necessary.

  Moreover, in order to improve heat resistance and mechanical strength, you may copolymerize aromatic monomer components, such as 50 mol% or less terephthalic acid, as a dicarboxylic acid component. Examples of PLA resins containing such components include trade name “Easter Bio” (manufactured by Eastman Chemicals) and trade name “Ecoflex” (manufactured by BASF).

  In addition, as an aliphatic polyester obtained by ring-opening polymerization of cyclic lactones, one or more kinds of cyclic monomers selected from ε-caprolactone, δ-valerolactone, β-methyl-δ-valerolactone and the like may be polymerized. The aliphatic polyester obtained by this is mentioned. Thus, what is obtained by ring-opening condensation of ε-caprolactone is commercially available, for example, “Cell Green” (manufactured by Daicel Chemical Industries).

  Examples of synthetic aliphatic polyesters include copolymers of cyclic acid anhydrides such as succinic anhydride and oxiranes such as ethylene oxide and propylene oxide.

  Furthermore, in the laminated film of the present invention, a PLA resin, a diol and a dicarboxylic acid copolymer can also be suitably used. Examples of the structure of this copolymer include a random copolymer, a block copolymer, and a graft copolymer, and any structure may be used. However, a block copolymer or a graft copolymer is preferable from the viewpoint of impact resistance and transparency of the film.

  Specific examples of a random copolymer of a PLA resin, a diol, and a dicarboxylic acid include, for example, “GS-Pla” (manufactured by Mitsubishi Chemical Corporation), and specific examples of a block copolymer or a graft copolymer. Is, for example, “Plamate” (manufactured by Dainippon Ink & Chemicals, Inc.).

<Inner layer>
The inner layer of the laminated film of the present invention comprises a resin composition containing a thermoplastic resin as a main component. The type of thermoplastic resin constituting the inner layer is not particularly limited as long as it is a resin composition that can adhere to the adhesive resin constituting the adhesive layer, but a polystyrene resin, a polyolefin resin, or a polyamide resin is preferably used. It is done.

  When a polystyrene resin is used as the resin composition constituting the inner layer, a block copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon is preferably used from the viewpoint of being usable as a heat-shrinkable film. Used. The “block copolymer” used in the present specification is a pure block in which the resin is pure for each block, a random block in which the copolymer components are mixed to form a block, and the copolymer component concentration Includes any tapered block or the like having a taper.

  Examples of the styrenic hydrocarbon include styrene, (p-, m- or o-) methylstyrene, (2,4-, 2,5-, 3,4- or 3,5-) dimethylstyrene, p- alkyl styrene such as t-butyl styrene; alkoxy styrene such as (p-, m- or o-) methoxy styrene, (o-, m- or p-) ethoxy styrene; (o-, m- or p-) Examples include carboxyalkyl styrene such as carboxymethyl styrene; alkyl ether styrene such as p-vinylbenzylpropyl ether; alkylsilyl styrene such as p-trimethylsilyl styrene; and vinylbenzyl dimethoxy phosphide. The styrenic hydrocarbon block may contain a copolymerizable monomer other than these homopolymers, these copolymers and / or styrenic hydrocarbons.

  Examples of the conjugated diene hydrocarbon include butadiene, isoprene, 1,3-pentadiene, etc., and the conjugated diene hydrocarbon block includes these homopolymers, copolymers thereof and / or conjugated diene carbonization. A copolymerizable monomer other than hydrogen may be included in the block.

  One of the block copolymers of styrene hydrocarbons and conjugated diene hydrocarbons preferably used in the present invention is a styrene-butadiene in which the styrene hydrocarbon is styrene and the conjugated diene hydrocarbon is butadiene. It is a system block copolymer (SBS). SBS preferably has a styrene / butadiene mass% ratio of about 60 to 95/5 to 40, more preferably about 60 to 90/10 to 40. Furthermore, the melt flow rate (MFR) measurement value (measurement conditions: temperature 200 ° C., load 49 N) is 2 g / 10 min or more, preferably 3 g / 10 min or more, and 15 g / 10 min or less, preferably 10 g / It is desirable that it is 10 minutes or less.

  In the present invention, when the resin composition constituting the main component of the inner layer is a polystyrene resin, the polystyrene resin may be a single substance or a mixed resin of two or more kinds. However, the refractive index of the polystyrene resin alone or mixed resin constituting the inner layer ensures good transparency, for example, the printed pattern can be clearly seen even when printed on the back, and thus an excellent appearance is obtained. From the viewpoint, it is 1.54 or more, preferably 1.55 or more, more preferably 1.56 or more, further preferably 1.57 or more, and the upper limit is 1.59 or less, preferably 1.585 or less, Preferably it is 1.58 or less.

  In general, when a laminated film is manufactured, a portion (trimming loss or the like) that does not become a product is generated when the clip portion is slit or slitted according to the product width. Such a non-product part is usually added as a recycled product (regeneration addition) at the time of extrusion. In the case of a laminated film as in the present invention, raw materials for the outer layer, the inner layer, and the adhesive layer are mixed in the slit non-product part (recycled product). When such a mixture is regenerated and added to the inner layer or the outer layer, the transparency may be lowered. Therefore, in applications that require transparency, the refractive index of the resin constituting the outer layer, the inner layer, and the adhesive layer needs to be as close as possible in order to maintain the transparency.

  The refractive index of the resin constituting the outer layer varies somewhat depending on the comonomer of the polyester resin constituting the outer layer, but most of the polyester resin is in the range of 1.55 to 1.585. Therefore, by setting the refractive index of the resin constituting the outer layer within a predetermined range, the transparency of the film can be improved even when a mixture of the outer layer resin, the inner layer resin and the adhesive layer resin is regenerated and added to the inner layer and / or the outer layer. Can be maintained.

  On the other hand, when the inner layer is composed of a polystyrene-based resin, the block copolymer of the styrene-based hydrocarbon and the conjugated diene-based hydrocarbon is used in order to adjust the refractive index of the resin constituting the inner layer within a predetermined range. It is preferable. The block copolymer of the styrene hydrocarbon and the conjugated diene hydrocarbon adjusts the refractive index to a substantially desired value by adjusting the composition ratio of the styrene hydrocarbon and the conjugated diene hydrocarbon. It is possible. The predetermined refractive index can also be achieved by a single block copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon or a mixed resin of two or more types. Therefore, the refractive index of the block copolymer of styrene hydrocarbon and conjugated diene hydrocarbon used as the main component of the inner layer is 1.54 or more, preferably 1.55 or more, more preferably 1.555 or more. And 1.60 or less, preferably 1.59 or less, more preferably 1.585 or less.

  When two or more polystyrene resins are used as the resin constituting the inner layer, the refractive index can be determined by additively calculating the refractive index of each single resin by a mass fraction. For example, in the case of a styrene / butadiene block copolymer of styrene / butadiene = 95/5, since it varies depending on the block structure and the like, it cannot be generally stated, but since the refractive index is approximately 1.587, this copolymer In the case of mixing, the average refractive index can be adjusted within a predetermined range by blending with a styrene-butadiene block copolymer having a low refractive index.

  Examples of the styrene-butadiene block copolymer include: Asaflex Chemicals Co., Ltd .: Asaflex Series, Denki Kagaku Kogyo Co., Ltd .: Clearen Series, Chevron Phillips: K Resin, BASF: Styro Lux, manufactured by Atofina: Finacria is commercially available.

  As the polystyrene resin, a styrene-isoprene-butadiene block copolymer (SIBS) can also be suitably used. In SIBS, the mass% ratio of styrene / isoprene / butadiene is preferably 60 to 85/10 to 40/5 to 30, and more preferably 60 to 80/10 to 25/5 to 20. The melt flow rate (MFR) measured value (measuring conditions: temperature 200 ° C., load 49 N) is 2 g / 10 min or more, preferably 3 g / 10 min or more, and 15 g / 10 min or less, preferably 10 g / 10. Is less than a minute. If the butadiene content and the isoprene content are within the above ranges, the cross-linking reaction of butadiene heated inside the extruder or the like can be suppressed, the generation of gel-like materials can be suppressed, and the raw material unit price can also be suppressed low. Therefore, it is preferable.

  As for the styrene-isoprene-butadiene block copolymer, for example, Asaflex I series manufactured by Asahi Kasei Chemicals Corporation is commercially available.

  The polystyrene resin has a weight (mass) average molecular weight (Mw) of 100,000 or more, preferably 150,000 or more, 500,000 or less, preferably 400,000 or less, more preferably 300,000 or less. It is a range. If the weight (mass) average molecular weight of the polystyrene-based resin is 100,000 or more, it is preferable without any defect that causes deterioration of the film. Furthermore, it is preferable that the weight (mass) average molecular weight of the polystyrene-based resin is 500,000 or less because there is no need to adjust the flow characteristics and there are no defects such as deterioration of extrudability.

The polystyrene-based resin has a storage elastic modulus (E ′) at 0 ° C. of 1.00 × 10 ⁹ Pa or more, preferably 1.50 × 10 ⁹ Pa or more, preferably 3.00 × 10 ⁹ Pa or less. Is 2.50 × 10 ⁹ Pa or less. The storage elastic modulus (E ′) at 0 ° C. represents the rigidity of the film, that is, the strength of the film. By having a storage elastic modulus equal to or higher than the lower limit, a film having rigidity in addition to transparency can be obtained. Such a storage elastic modulus is achieved by the above-mentioned polystyrene resin, styrene hydrocarbon and conjugated diene hydrocarbon block copolymer, two or more mixed resins, or a blend with other resins as long as transparency is not impaired. It's okay.

  In the case of a mixed resin system or a blend system with another resin, it has been found that good results can be obtained by selecting a resin that bears fracture resistance and a resin that bears rigidity. That is, it is possible to satisfy a desired refractive index and a desired storage elastic modulus (E ′) by combining a polystyrene-based resin having high rupture resistance and a highly rigid polystyrene-based resin or the like or another resin.

The polystyrene-based resin responsible for fracture resistance has a storage elastic modulus at 0 ° C. of 1.00 × 10 ⁸ Pa or more and 1.00 × 10 ⁹ Pa or less, and at least one peak temperature of loss elastic modulus is −20 ° C. SBS having the following viscoelastic properties is preferred. At the peak temperature of the loss modulus, the temperature on the low temperature side mainly shows fracture resistance. Although the characteristics vary depending on the stretching conditions, if the peak temperature of the loss modulus is −20 ° C. or lower before stretching, sufficient film breakability can be imparted to the laminated film.

Examples of the polystyrene resin having rigidity include a copolymer of a styrene hydrocarbon having a storage elastic modulus (E ′) at 0 ° C. of 2.00 × 10 ⁹ Pa or more, such as a styrene carbonization having a controlled block structure. Examples thereof include hydrogen and a conjugated diene hydrocarbon block copolymer, polystyrene, a styrene hydrocarbon and an aliphatic unsaturated carboxylic acid ester copolymer.

The styrene hydrocarbon and conjugated diene hydrocarbon block copolymer having a controlled block structure has a storage elastic modulus (E ′) at 0 ° C. of 2.00 × 10 ⁹ Pa or more, preferably 2.50 × 10. SBS is ⁹ Pa or more and 4.00 × 10 ⁹ Pa or less, preferably 3.00 × 10 ⁹ Pa or less. The SBS styrene-butadiene composition ratio satisfying this is preferably adjusted to about styrene / butadiene = 95/5 to 80/20. Further, the block copolymer structure and the structure of each block portion are preferably a random block and a tapered block.

  In order to control the shrinkage characteristics, it is preferable that the peak temperature of the loss elastic modulus of the polystyrene resin is 40 ° C. or higher. More preferably, it is preferable that there is no clear peak temperature of loss elastic modulus at 40 ° C. or lower. When the peak temperature of the loss elastic modulus does not exist up to 40 ° C., the storage elastic modulus characteristic is almost the same as that of polystyrene, so that the rigidity of the film can be imparted. Moreover, the peak temperature of a loss elastic modulus exists in 40 degreeC or more, Preferably it is 40 degreeC or more and 90 degrees C or less. This peak temperature is a factor mainly affecting the shrinkage rate. When this temperature is 40 ° C. or lower, the natural shrinkage is lowered, and when it is 90 ° C. or higher, the low temperature shrinkage is lowered. End up.

  Examples of polymerization methods capable of satisfying the above viscoelastic properties are shown below. After a part of styrene or butadiene is charged to complete the polymerization, a mixture of styrene monomer and butadiene monomer is charged and the polymerization reaction is continued. In this way, butadiene having higher polymerization activity is preferentially polymerized, and finally a block composed of a single monomer of styrene is produced. For example, styrene is homopolymerized first to complete the polymerization, and then a mixture of styrene monomer and butadiene monomer is charged to continue the polymerization, whereby the monomer ratio of styrene and butadiene is between the styrene block and the butadiene block. As a result, a styrene-butadiene block copolymer having a styrene-butadiene copolymer portion gradually changing is obtained. By introducing such a site, it becomes possible to obtain a polymer having the above viscoelastic properties. In this case, the two peaks due to the butadiene block and the styrene block as described above cannot be clearly confirmed, and it appears that only one peak exists. In other words, in block structures such as SBS of random blocks in which pure blocks and butadiene blocks are clearly present, Tg due to butadiene blocks mainly exists below 0 ° C, so the storage elastic modulus at 0 ° C is a predetermined value. It becomes difficult to do more.

  The weight (mass) average molecular weight is adjusted such that the measured value of melt flow rate (MFR) (measurement conditions: temperature 200 ° C., load 49 N) is 2 g / 10 min or more and 15 g / 10 min or less. The blend amount of the styrene-butadiene block copolymer imparting this rigidity is appropriately adjusted according to the characteristics of the laminated film. For example, in the case of a heat-shrinkable film, the blend amount is generally 20% by mass or more and 70% by mass or less. It is preferable to adjust the range. If the blend amount is 70% by mass or less, the rigidity of the film can be greatly improved without significantly reducing the fracture resistance. Moreover, if it is 20 mass% or more, there exists a rigidity provision effect with respect to a film.

  As a polystyrene resin blended as a resin bearing rigidity, a general polystyrene resin (GPPS) having a weight (mass) average molecular weight (Mw) of 100,000 or more and 500,000 or less is preferable. Since the polystyrene has a very high glass transition temperature (peak temperature of loss modulus) of about 100 ° C., the blend amount is 20% by mass or less, preferably 15% by mass or less, more preferably 10% by mass or less. Is desirable. When the blend amount is 20% by mass or less, the thermal shrinkage rate of the laminated film at a low temperature, that is, the thermal shrinkage rate after being immersed in hot water at 70 ° C. for 10 seconds can be 10% or more.

  As the styrenic hydrocarbon in the styrene-based hydrocarbon and aliphatic unsaturated carboxylic acid ester copolymer blended as a resin bearing rigidity, styrene, o-methyl styrene, p-methyl styrene, α-methyl styrene and the like are preferable. As the aliphatic unsaturated carboxylic acid ester, methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate and the like are preferable. Here, (meth) acrylate indicates acrylate and / methacrylate. Preferably, a copolymer of styrene and butyl (meth) acrylate is used. More preferably, styrene is in the range of 70% by mass to 90% by mass, the glass transition temperature (peak temperature of loss elastic modulus) is 50 ° C. or higher and 90 ° C. or lower, and melt flow rate (MFR) measurement values (measurement conditions: A material having a temperature of 200 ° C. and a load of 49 N) of 2 g / 10 min to 15 g / 10 min is used.

  The blend amount of the styrene-based hydrocarbon and the aliphatic carboxylic acid ester copolymer is appropriately adjusted depending on the composition ratio, but is in the range of 20% by mass to 70% by mass with respect to the total mass of the resin constituting the inner layer. It is adjusted with. If the blend amount is 70% by mass or less, the rigidity of the film can be greatly improved without significantly reducing the fracture resistance. Moreover, if it is 20 mass% or more, a film rigidity effect can be expressed.

  In addition, a polyolefin resin (hereinafter referred to as “PO resin”) can be suitably used for the inner layer of the laminated film of the present invention.

  The kind of PO resin used for the inner layer of the laminated film of the present invention is not particularly limited. Usable PO resins include polyethylene resins, polypropylene resins, and ethylene copolymers such as ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer. It is done. Especially, it is preferable to use a polyethylene-type resin, a polypropylene-type resin, or these mixtures from a viewpoint of a heat contraction rate and a moldability. There are various types of polyethylene resins and polypropylene resins depending on the polymerization method and copolymerization component, and the range is not particularly limited. Preferred types are shown below.

The polyethylene resin used in the inner layer of the laminated film of the present invention is usually a high density polyethylene resin (HDPE) having a density of 0.94 g / cm ³ or more and 0.97 g / cm ³ or less, and a density of 0.92 g / cm. ³ to 0.94 g / cm ³ or less in density polyethylene resin (MDPE), include density 0.92 g / cm ³ less than the low-density polyethylene resin (LDPE), and linear low density polyethylene resin (LLDPE) . Among these, linear low density polyethylene resin (LLDPE) is particularly preferably used from the viewpoint of stretchability, impact resistance of the film, transparency, and the like.

  Examples of the linear low density polyethylene resin (LLDPE) include a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, preferably 4 to 12 carbon atoms. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 3-methyl-1-butene, 4- Examples thereof include methyl-1-pentene. Among these, 1-butene, 1-hexene, and 1-octene are preferably used. Moreover, you may use the alpha olefin to copolymerize individually by 1 type or in combination of 2 or more types.

Preferred examples density of the polyethylene resin, the lower limit is preferably 0.800 g / cm ³ or more, more preferably 0.850 g / cm ³ or more, more preferably 0.900 g / cm ³ or more, the upper limit is , preferably 0.950 g / cm ³ or less, more preferably 0.940 g / cm ³ or less, more preferably 0.930 g / cm ³ or less. For example, in the case of a heat-shrinkable film, if the density is 0.800 g / cm ³ or more, the waist (rigidity at room temperature) and heat resistance of the entire film are not significantly lowered, which is preferable in practice. On the other hand, if the density is 0.950 g / cm ³ or less, the drawability at a low temperature is maintained, and a sufficient heat shrinkage rate is obtained in a practical temperature range (about 70 ° C. or more and about 90 ° C. or less).

  As the polyethylene resin, those having a melt flow rate (MFR: JIS K7210, temperature: 190 ° C., load: 21.2 N) of 0.1 g / 10 min to 10 g / 10 min are preferably used. When the MFR is 0.1 g / 10 min or more, the extrudability can be maintained satisfactorily. On the other hand, when the MFR is 10 g / 10 min or less, the thickness unevenness of the laminated film and the mechanical strength are hardly lowered, which is preferable.

  Next, examples of the polypropylene resin used in the inner layer of the laminated film of the present invention include homopropylene resin, random polypropylene resin, block polypropylene resin, and propylene-ethylene rubber. Among these, a random polypropylene resin is particularly preferably used from the viewpoints of stretchability, transparency, rigidity, and the like.

  In the random polypropylene resin, the α-olefin to be copolymerized with propylene preferably includes those having 2 to 20 carbon atoms, more preferably those having 4 to 12 carbon atoms, such as ethylene, 1-butene, 1-pentene. 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene and the like. In the present invention, from the viewpoints of stretchability, heat shrinkage characteristics, impact resistance, transparency, rigidity, and the like of the film, random polypropylene having an ethylene unit content of 2% by mass to 10% by mass as the α-olefin is particularly preferable. Preferably used. Moreover, you may use the alpha olefin to copolymerize individually by 1 type or in combination of 2 or more types.

  The melt flow rate (MFR) of the polypropylene resin is not particularly limited, but the MFR (JIS K7210, temperature: 230 ° C., load: 21.2 N) is preferably 0.5 g / 10 min or more. More preferably, it is 1.0 g / 10 min or more, and preferably 15 g / 10 min or less, more preferably 10 g / 10 min or less.

  More specifically, these polyethylene-based resins and polypropylene-based resins can be used as polyethylene-based resins under the trade names “Novatech HD, LD, LL”, “Kernel”, “Toughmer A, P” (manufactured by Nippon Polytech Co., Ltd.), “Suntech HD”. , LD "(manufactured by Asahi Kasei Co., Ltd.)," HIZEX "," ULTZEX "," EVOLUE "(manufactured by Mitsui Chemicals)," Moretech "(manufactured by Idemitsu Kosan Co., Ltd.)," UBE polyethylene "," UMERIT "(manufactured by Ube Industries, Ltd.)," It is commercially available as NUC polyethylene, “Nackflex” (manufactured by Nihon Unicar), “engage” (manufactured by Dow Chemical). Also, as polypropylene resins, trade names “NOVATEC PP”, “WINTEC”, “Toughmer XR” (manufactured by Nippon Polypro), “Mitsui Polypro” (manufactured by Mitsui Chemicals), “Sumitomo Noblen”, “Tough Selenium”, “Excellen EPX” ( (Made by Sumitomo Chemical Co., Ltd.), “IDEMITSU PP”, “IDEMITSU TPO” (made by Idemitsu Kosan Co., Ltd.), “Adflex”, “Adsyl” (made by Sun Allomer), etc. These copolymers can be used alone or in admixture of two or more.

  In addition, as the PO-based resin, a copolymer of a monomer copolymerizable with ethylene can also be suitably used. Examples of the copolymer of a monomer copolymerizable with ethylene include an ethylene-vinyl acetate copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-methyl acrylate copolymer. Among these, an ethylene-vinyl acetate copolymer is particularly preferably used from the viewpoints of transparency and economy.

  The ethylene content of the ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-methyl acrylate copolymer is 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. And 95% by mass or less, preferably 90% by mass or less, more preferably 85% by mass or less. If ethylene content rate is 50 mass% or more, the rigidity and heat resistance of the whole film can be maintained favorable. Moreover, it is preferable if the ethylene content is 95% by mass or less, since the effect on the fracture resistance of the film can be sufficiently obtained and the transparency can be maintained.

  Examples of commercially available ethylene-vinyl acetate copolymer (EVA) include “Evaflex” (manufactured by Mitsui DuPont Polychemical Co., Ltd.), “Novatech EVA” (manufactured by Mitsubishi Chemical Corporation), and “Ebaslene” (Dainippon Ink Chemical Co., Ltd.). Kogyo Co., Ltd.) and “Evaate” (Sumitomo Chemical Co., Ltd.). Moreover, as a commercial item of ethylene-ethyl acrylate copolymer (EEA), for example, “Evaflex EEA” (manufactured by Mitsui DuPont Polychemical Co., Ltd.), and as an ethylene-methyl acrylate copolymer, “Elvalloy AC” (Mitsui DuPont Poly) is used. Chemical Co., Ltd.) and the like.

  The MFR of the copolymer of monomers copolymerizable with ethylene is not particularly limited, but the MFR (JIS K7210, temperature: 190 ° C., load: 21.2 N) is preferably 0.5 g / It is 10 minutes or more, more preferably 1.0 g / 10 minutes or more, and preferably 15 g / 10 minutes or less, more preferably 10 g / 10 minutes or less.

  The weight average molecular weight of the PO-based resin is 50,000 or more, preferably 100,000 or more, 700,000 or less, preferably 600,000 or less, more preferably 500,000 or less. If the weight average molecular weight of the PO-based resin is within the above range, practical physical properties such as desired mechanical properties and heat resistance can be expressed, an appropriate melt viscosity can be obtained, and good moldability can be obtained.

  Further, the production method of the PO-based resin is not particularly limited, and a known polymerization method using a known olefin polymerization catalyst, for example, a multisite catalyst or a metallocene catalyst represented by a Ziegler-Natta type catalyst. Examples thereof include a slurry polymerization method, a solution polymerization method, a bulk polymerization method, and a gas phase polymerization method using a single site catalyst represented by the above, and a bulk polymerization method using a radical initiator.

  Furthermore, in the present invention, an appropriate amount of petroleum resin or the like can be added as necessary for the purpose of adjusting the shrinkage ratio to the PO-based resin. By adding a petroleum resin, stretchability at low temperatures can be maintained, and improvement in heat shrinkage characteristics can be expected.

  Examples of the petroleum resin include cyclopentadiene or an alicyclic petroleum resin from a dimer thereof and an aromatic petroleum resin from a C9 component. Petroleum resins are known to exhibit relatively good compatibility when mixed with PO-based resins and the like, but it is preferable to use hydrogenated derivatives in view of color tone, thermal stability, and compatibility.

  Specifically, Mitsui Chemicals 'product names "Hilets", "Petrogin", Arakawa Chemical Industry's product name "Arcon", Idemitsu Petrochemicals' product name "Imabe", Tonex's product name Commercial products such as “Escollets” can be used.

  Some petroleum resins mainly have various softening temperatures depending on the molecular weight. In the present invention, those having a softening temperature of 100 ° C. or higher and 150 ° C. or lower, preferably 110 ° C. or higher and 140 ° C. or lower are preferably used. It is done. Here, if the softening temperature is 100 ° C. or higher, the petroleum resin bleeds on the surface of the sheet when mixed with the PO-based resin, causing blocking, or the mechanical strength of the entire sheet is lowered and easily broken. This is practically preferable. On the other hand, if it is 150 degrees C or less, compatibility with PO-type resin is maintained favorable, petroleum oil will bleed on the film surface with time, and it will not cause blocking or a transparency fall, and is preferable.

  The amount of the petroleum resin mixed is preferably 5 to 80 parts by mass with respect to 100 parts by mass of the PO resin constituting the inner layer. Here, if the mixing amount of the petroleum resin is 5 parts by mass or more, the effect of improving the glossiness and shrinkage characteristics of the film surface can be obtained. On the other hand, if it is 80 parts by mass or less, it is possible to suppress the occurrence of problems such as the petroleum resin bleeds on the surface of the film over time and the films are likely to block each other or the impact resistance is reduced. . For these reasons, the amount of the petroleum resin added to the inner layer is more preferably 10 parts by mass or more and 60 parts by mass or less with respect to 100 parts by mass of the PO resin constituting the inner layer.

  When the resin composition constituting the inner layer is a PO-based resin, the refractive index of the PO-based resin is 1.40 or more, preferably 1 from the viewpoint of maintaining good transparency and transparency during regeneration addition. It is desirable that it is 45 or more, more preferably 1.47 or more, and 1.55 or less, preferably 1.53 or less, more preferably 1.50 or less.

  In the laminated film of the present invention, a polyamide resin (hereinafter referred to as “PA resin”) can also be used as the thermoplastic resin constituting the inner layer. As the PA resin, it is preferable to use a nylon resin (Ny) from the viewpoint of pinhole resistance. Examples of Ny include polymers of condensed units such as 6 nylon, 66 nylon, 69 nylon, 6-66 nylon, 12 nylon, 11 nylon, 610 nylon, 612 nylon, 6I-6T nylon, and MXD6 nylon, or two of these. Copolymers with the above, and mixtures thereof can also be mentioned. Among them, it is preferable to use 6 nylon or 6-66 nylon.

  In the laminated film of the present invention, the resin composition used in the outer layer can be included in the inner layer. By including the resin composition used in the outer layer in the inner layer, it contributes to the recycling of the film and can be expected to improve the fracture resistance of the film. The content of the resin constituting the outer layer that can be added to the inner layer is preferably 30 parts by mass or less, more preferably 25 parts by mass or less, and even more preferably 23 parts by mass or less with respect to 100 parts by mass of the resin constituting the inner layer. . By setting the resin constituting the outer layer to 30 parts by mass or less with respect to 100 parts by mass of the resin constituting the inner layer, the transparency of the obtained laminated film can be maintained.

<Adhesive layer>
In the laminated film of the present invention, the adhesive resin used in the adhesive layer has a portion having reactivity or affinity for the polyester resin of the outer layer and a portion having affinity for the thermoplastic resin of the inner layer. Resins are preferably used.

  Here, “having reactivity or affinity for the polyester resin” means having a functional group having a high affinity with the polyester resin or a functional group capable of reacting with the polyester resin. Examples of functional groups having such properties include acid anhydride groups, carboxylic acid groups, carboxylic acid ester groups, carboxylic acid chloride groups, carboxylic acid amide groups, carboxylic acid groups, sulfonic acid groups, and sulfonic acid ester groups. , Sulfonic acid chloride groups, sulfonic acid amide groups, sulfonic acid groups, epoxy groups, amino groups, imide groups, or oxazoline groups, among others, acid anhydride groups, carboxylic acid groups, or carboxylic acid esters Groups are preferred.

  In addition, the “part having affinity with the thermoplastic resin” means that, for example, when the thermoplastic resin forming the inner layer is a polyolefin resin, it has a chain having an affinity with the polyolefin resin. For example, when the thermoplastic resin forming the inner layer is a polystyrene resin, it means that it has a chain having an affinity for the polystyrene resin. In the case where a polyolefin resin is used for the inner layer, more specifically, it means having a linear or branched saturated hydrocarbon moiety as a main chain, a block chain, or a graft chain. As specific examples, polyolefin resins or resins obtained by hydrogenating copolymers of styrene hydrocarbons and conjugated diene hydrocarbons, such as styrene-ethylene-butadiene copolymers, styrene-ethylene-propylene copolymers, Examples include styrene-ethylene-butylene copolymers.

As the adhesive resin, at least one copolymer or resin composition selected from the group consisting of the following (a-1), (a-2) and (a-3) is preferably used.
(A-1) Aromatic vinyl hydrocarbon-conjugated diene copolymer, hydrogenated aromatic vinyl hydrocarbon-conjugated diene copolymer, and aromatic vinyl hydrocarbon-conjugated diene copolymer or hydrogen thereof Resin compound with polar group introduced into additive (a-2) Ethylene monomer unit, vinyl acetate, acrylic acid, (meth) acrylic acid, ethyl (meth) acrylate, methyl (meth) acrylic acid, maleic anhydride A copolymer composed of an acid and one unit selected from the group consisting of glycidyl (meth) acrylate (hereinafter referred to as “ethylene-based copolymer”).
(A-3) Modified polyolefin resin

First, a copolymer of an aromatic hydrocarbon and a conjugated diene hydrocarbon or a hydrogenated derivative (a-1) of these copolymers will be described.
As the aromatic hydrocarbon, styrene is preferably used, and styrene homologues such as α-methylstyrene can also be used. As conjugated diene hydrocarbons, 1,3-butadiene, 1,4-butadiene, 1,2-isoprene, 1,4-isoprene, 1,3-pentadiene, etc. are used, and these are hydrogenated derivatives. There may be. These may be used alone or in admixture of two or more.

  In the copolymer of the aromatic hydrocarbon and conjugated diene hydrocarbon or the hydrogenated derivative thereof, the content of the aromatic hydrocarbon is preferably 5 based on the mass of the entire copolymer (100% by mass). It is at least 7 mass%, more preferably at least 7 mass%, even more preferably at least 10 mass%, and preferably at most 50 mass%, more preferably at most 40 mass%, still more preferably at most 35 mass%.

  As a hydrogenated derivative of a copolymer of an aromatic hydrocarbon and a conjugated diene hydrocarbon, a hydrogenated derivative of a styrene-conjugated diene copolymer can be preferably used. The details of the hydrogenated derivative of the styrene-conjugated diene copolymer and the production method thereof are disclosed in JP-A-2-15843, JP-A-2-305814, and JP-A-3-72512. ing.

  As the aromatic hydrocarbon-conjugated diene hydrocarbon copolymer, each of the above-exemplified copolymers can be used alone or in admixture of two or more. When two or more kinds are mixed and used, the blending ratio is adjusted so that the content of the aromatic hydrocarbon is within the above range as the whole mixed resin.

  Commercially available products of aromatic hydrocarbon-conjugated diene hydrocarbon copolymer include styrene-butadiene block copolymer, trade name “Tufprene” (manufactured by Asahi Kasei Chemical Co., Ltd.), trade name “Asaflex” (Asahi Kasei Chemical) As a hydrogenated derivative of styrene-butadiene block copolymer, trade name “Tuftec H” (Asahi Kasei Chemicals), trade name “Clayton G” (Clayton Japan), styrene-butadiene random copolymer As a hydrogenated derivative, the product name “Dynalon” (manufactured by JSR), and as a hydrogenated derivative of a styrene-isoprene block copolymer, the product name “Septon” (manufactured by Kuraray), a styrene-vinylisoprene block copolymer elastomer. The product name “Hiblar” (manufactured by Kuraray Co., Ltd.) and the like.

  Examples of the polar group introduced into the copolymer of aromatic hydrocarbon and conjugated diene hydrocarbon or a hydrogenated derivative thereof include maleic anhydride-modified SEBS, maleic anhydride-modified SEPS, epoxy-modified SEBS, A typical example is epoxy-modified SEPS. These copolymers can be used alone or in admixture of two or more. When acid modification is performed with maleic anhydride, the amount of maleic anhydride modification is 0.5% by mass or more, preferably 1.0% by mass or more, more preferably 1.5% by mass or more, and 5.0% by mass. % Or less, preferably 4.0% by mass or less, more preferably 3.0% by mass or less. If the amount of maleic anhydride modification is within the above range, good peeling strength can be maintained without causing the problem of delamination.

  Specifically, trade names “Tuftec M” (manufactured by Asahi Kasei Chemicals), “Epofriend” (manufactured by Daicel Chemical Industries), etc. are commercially available.

  Next, the ethylene copolymer (a-2) will be described. Examples of the ethylene copolymer include ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene- (meth) acrylic acid copolymer (EMA), and ethylene- ( (Meth) ethyl acrylate copolymer (EEA), ethylene-methyl (meth) acrylic acid copolymer (EMMA), ethylene-vinyl acetate-maleic anhydride terpolymer, ethylene-ethyl acrylate-maleic anhydride Examples include terpolymers, ethylene-glycidyl methacrylate copolymers, ethylene-vinyl acetate-glycidyl methacrylate terpolymers, and ethylene-ethyl acrylate-glycidyl methacrylate terpolymers. Among them, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid copolymer (EAA), ethylene-ethyl acrylate copolymer (EEA), ethylene- (meth) acrylic acid copolymer (EMA), An ethylene-methyl (meth) acrylic acid copolymer (EMMA) can be suitably used.

  The ethylene copolymer has an ethylene monomer unit content of 50% by mass or more, preferably 60% by mass or more, more preferably 65% by mass or more, and 95% by mass or less, preferably 90% by mass or less. More preferably, the content is 85% by mass or less. If the content of the ethylene monomer unit is 95% by mass or less, the flexibility can be sufficiently maintained, and when a stress is applied to the film, a buffering action to the stress generated between the outer layer and the inner layer works. Delamination at room temperature can be suppressed.

  As the ethylene-based copolymer, those having an MFR (JIS K7210, temperature: 190 ° C., load: 21.2 N) of 0.1 g / 10 min or more and 10 g / 10 min or less are suitably used. When the MFR is 0.1 g / 10 min or more, the extrudability can be maintained satisfactorily. On the other hand, when the MFR is 10 g / 10 min or less, the thickness unevenness of the laminated film and the mechanical strength are hardly lowered, which is preferable.

  Examples of commercially available ethylene copolymers include ethylene-vinyl acetate copolymer, trade name “Evaflex EV40LX” (Mitsui / DuPont Polychemical Co.), and ethylene-acrylic acid copolymer, trade name “ NUC copolymer ”(manufactured by Nihon Unicar),“ Evaflex-EEA ”(manufactured by Mitsui DuPont Polychemical),“ Lex Pearl EAA ”(manufactured by Nippon Polyethylene), ethylene- (meth) acrylic acid copolymer, Trade name “Elvalloy” (Mitsui / DuPont Polychemical Co., Ltd.), “Lex Pearl EMA” (Nihon Polyethylene Co., Ltd.), Ethylene-ethyl acrylate copolymer, Trade Name “Lex Pearl EEA” (Nihon Polyethylene Co., Ltd.) As an ethylene-methyl (meth) acrylic acid copolymer, the trade name “ACRIFT”, (Sumitomo Trade name), ethylene-vinyl acetate-maleic anhydride terpolymer, trade name “Bondaine” (manufactured by Sumitomo Chemical Co., Ltd.), ethylene-glycidyl methacrylate copolymer, ethylene-vinyl acetate-glycidyl methacrylate tri Examples of the original copolymer, ethylene-ethyl acrylate-glycidyl methacrylate terpolymer include trade name “bond first” (manufactured by Sumitomo Chemical Co., Ltd.).

  Next, the modified polyolefin resin (a-3) will be described. In the present invention, the modified polyolefin resin refers to a resin mainly composed of an unsaturated carboxylic acid or an anhydride thereof, or a polyolefin modified with a silane coupling agent. Examples of unsaturated carboxylic acids or anhydrides include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, citraconic acid, citraconic anhydride, itaconic acid, itaconic anhydride, or monoepoxy compounds of these derivatives and the above acids. Ester compounds of the above, and a reaction product of a polymer having a group capable of reacting with these acids in the molecule and an acid. These metal salts can also be used. Among these, maleic anhydride is more preferably used. Moreover, these copolymers can be used individually or in mixture of 2 or more types, respectively.

  Examples of the silane coupling agent include vinyltriethoxysilane, methacryloyloxytrimethoxysilane, and γ-methacryloyloxypropyltriacetyloxysilane.

  In order to produce the modified polyolefin resin, for example, these modified monomers can be copolymerized in the stage of polymerizing the polymer in advance, or these modified monomers can be graft-copolymerized to the polymer once polymerized. In the modification, these modifying monomers are used alone or in combination, and those having a content in the range of 0.1% by mass or more and 5% by mass or less are preferably used. Of these, those that have been graft-modified are preferably used.

  Specifically, trade names “Admer” (Mitsui Chemicals), “Modic” (Mitsubishi Chemical) and the like are commercially available.

  The copolymer or resin of the above (a-1), (a-2) and (a-3) can be used alone or in admixture of two or more, and (a-1) and (a -2) or a mixed resin composition of (a-1) and (a-3). Specifically, there is a peak of loss tangent (tan δ) calculated from the ratio of storage elastic modulus to loss elastic modulus near or below normal temperature, and there are soft aromatic hydrocarbons and conjugated diene hydrocarbons. Mixing of a copolymer or a hydrogenated product thereof with a copolymer of a hard aromatic hydrocarbon and a conjugated diene hydrocarbon having a storage elastic modulus (E ′) at 50 to 100 ° C. of 100 Mpa or more More preferably, it is a resin composition. Copolymer of the soft aromatic hydrocarbon and conjugated diene hydrocarbon in the mixed resin composition, or the co-weight of the hydrogenated product, the hard aromatic hydrocarbon and conjugated diene hydrocarbon The mixing ratio of the coalescence is preferably 80:20, more preferably 40:60, and further preferably 30:70. When the mixing ratio is in the above range, the heat resistance of the adhesive layer is improved by the copolymer of the hard aromatic hydrocarbon and the conjugated diene hydrocarbon, and the outer layer and the inner layer of the laminated film are peeled off at a high temperature. And practically preferred. In addition, as the mixing ratio of the copolymer of the soft aromatic hydrocarbon and the conjugated diene hydrocarbon or the hydrogenated product thereof decreases, the peel strength at room temperature decreases, The inner layer and the outer layer are not peeled off due to rubbing between films during transportation or scratching with a human nail or the like, so that practically necessary adhesive strength can be maintained.

  In the laminated film of the present invention, the adhesive resin used in the adhesive layer is a resin composition containing a polyester elastomer, a resin composition containing a polyester elastomer modified with a modifier having a polar group, or these A resin composition containing the mixed resin composition as a main component can also be suitably used.

  A resin composition containing a polyester elastomer as a main component constituting the adhesive layer, a resin containing a polyester elastomer modified with a modifier having a polar group, or a resin containing a mixed resin composition of these resins as a main component By using the composition, it is possible to suppress delamination due to the adhesive strength peculiar to the elastomer, and the delamination is stronger due to the affinity between the polyester component constituting the polyester elastomer and the polyester resin constituting the outer layer. Can give strength.

  The polyester elastomer has a low glass transition temperature, a soft segment composed of a flexible polyether unit, a polyester unit, a polycarbonate unit, etc. that exhibits entropy elasticity, and a crystalline hard high-melting point polyester that prevents plastic deformation It is a block copolymer composed of hard segments composed of block units. The polyester elastomer includes a polyester elastomer modified with a modifier having a polar group.

  Examples of the hard segment constituting the polyester-based elastomer include polybutylene terephthalate units, polybutylene naphthalate units, polybutylene isophthalate units, and the like, and those obtained by copolymerizing these hard segment unit skeletons. On the other hand, examples of the soft segment include poly (tetramethylene oxide) glycol units, poly (ε-caprolactone) units, aliphatic polycarbonate diol units, and the like, and those obtained by copolymerizing these soft segment unit skeletons. The copolymer is a pure block copolymer, a random block copolymer, a tapered block copolymer, a multi-block copolymer, and further, the hard segment or the soft segment, or a copolymer thereof as a main skeleton, The side chain includes the soft segment, the hard segment, or a graft copolymer having a copolymer thereof, and the form of copolymerization is not particularly limited. In addition, the block unit may have any number of repeating units. Moreover, the polyester-type elastomer which comprised the polyester-type elastomer resin comprised from the said segment by the modifier | denaturant which has a polar group is also contained.

  Among them, polybutylene terephthalate-poly (tetramethylene oxide) glycol copolymer and polybutylene terephthalate-polybutylene isophthalate-poly (tetramethylene oxide) glycol copolymer can be suitably used as the polyester elastomer.

  The content rate of the hard segment in the polyester elastomer is 50% by mass or more, preferably 70% by mass or more, more preferably 75% by mass or more, further preferably based on the total amount of the hard segment and the soft segment. Is 80% by mass or more. When the hard segment content is 50% by mass or more, the effect of affinity with the polyester resin constituting the second layer is sufficiently exerted, and the heat resistance of the polyester elastomer is maintained even in a high-temperature atmosphere. Therefore, the shape of the laminate can be sufficiently maintained without causing a decrease in interlayer adhesive strength under a high temperature atmosphere.

  The number average molecular weight of the polybutylene terephthalate unit constituting the hard segment of the polyester-based elastomer is 400 or more, preferably 1,000 or more, more preferably 2,000 or more, and 10,000 or less, preferably 8, 000 or less, more preferably 6,000. If the number average molecular weight of the hard segment is in the range of 400 or more and 10,000 or less, the heat resistance of the polyester-based elastomer can be maintained, and the laminated body does not deteriorate the interlayer adhesive strength in a high temperature atmosphere. This is preferable because the shape can be sufficiently retained.

  On the other hand, the number average molecular weight of the polyalkyleneoxy glycol unit constituting the soft segment of the polyester elastomer is 500 or more, preferably 800 or more, more preferably 1,000 or more, and 3,000 or less, preferably 2,500 or less, more preferably 2,000 or less. When the number average molecular weight of the soft segment is 500 or more and 3,000 or less, the adhesive strength peculiar to the elastomer component can be sufficiently obtained, and the delamination strength is improved, which is preferable.

  Specific examples of polyester elastomer products include "Primalloy A Series", "Primalloy B Series" (Mitsubishi Chemical Corporation), "Perprene P Series" (Toyobo Co., Ltd.), "Hytrel" (Toray DuPont Co., Ltd.) ) And the like.

  Examples of the polar group of a polyester elastomer modified with a modifier having a polar group (hereinafter referred to as “modified polyester elastomer”) include, for example, an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, and a carboxylic acid ester group. Acid chloride group, carboxylic acid amide group, carboxylic acid group, sulphonic acid group, sulphonic acid ester group, sulphonic acid chloride group, sulphonic acid amide group, sulphonic acid group, epoxy group, amino group, imide group, or oxazoline group Among them, an acid anhydride group, a carboxylic acid group, or a carboxylic acid ester group is preferable.

  Examples of specific products of modified polyester elastomers include “Primalloy AP series” (Mitsubishi Chemical Corporation).

  The resin composition containing the polyester elastomer used in the adhesive layer or the resin composition containing the modified polyester elastomer is not limited to these simple substances, and two or more kinds may be mixed and used. In that case, the mixing amount can be appropriately determined according to the characteristics of the resin used.

  The adhesive layer in the laminated film of the present invention contains, for example, 0.1% by mass of hydrocarbon resins and styrene resins other than the resin composition containing a polyester elastomer and the resin composition containing a modified polyester elastomer. More than 40 mass% can be contained. When hydrocarbon resins are contained, crystallization of the hard segment can be suppressed, and flexibility and tackiness can be imparted. Moreover, when a styrene resin is contained, the heat resistance of the polyester elastomer can be improved, and an affinity with the polystyrene resin constituting the third layer can be imparted.

  In the laminated film of the present invention, the adhesive resin composition preferably has a storage elastic modulus (E ′) of 10 MPa or more in a temperature range of 50 ° C. to 100 ° C. under a vibration frequency of 10 Hz and a strain of 0.1%. Is 50 MPa or more, more preferably 100 MPa or more, 2,000 MPa or less, preferably 1,500 MPa or less, more preferably 1,000 MPa or less. If the storage elastic modulus (E ′) at 50 ° C. to 100 ° C. is 10 MPa or more, when used as a heat-shrink label, the film has sufficient rigidity even when the film is heated and shrunk in the process of attaching to a bottle. Therefore, wrinkles and vertical shrinkage can be suppressed. On the other hand, if the storage elastic modulus (E ′) is 1,000 MPa or less, the stretchability at low temperatures is good and the heat shrinkage rate can be secured, which is preferable.

  In the laminated film of the present invention, in order to adjust the storage elastic modulus (E ′) at 50 ° C. to 100 ° C. within the above range, the resin composition constituting the adhesive layer is adjusted as described in the present invention. Although it becomes possible, it is easy to achieve by using a thermoplastic resin having at least one crystal melting peak at 80 ° C. or higher, particularly when measured with a differential scanning calorimeter (DSC). It is also effective to use means such as increasing the thickness ratio.

<Difference width in the overlapped part>
Next, the shift width of the overlapping portion in the laminated film of the present invention will be described with reference to the drawings.
1 to 5, reference numeral 100 is a laminated film piece of the present invention, reference numeral 2 is an outer layer, reference numeral 4 is an adhesive layer, reference numeral 6 is an inner layer, reference numeral 8 is an overlapping portion, reference numeral 8w is an overlapping width, and reference numeral 10 is an outer layer. 2, reference numeral 12 is an end face of the adhesive layer 4, reference numeral 14 is an end face of the inner layer 6, reference numeral 16 is a seal portion, reference numeral 18 is a deviation, reference numeral 18 w is a deviation width, reference numeral A is one end side, reference numeral B is the other end side. Means each.

  1 to 4 are views showing a preferred embodiment of the present invention. 1 and 2 are cross-sectional views in the vicinity of the overlapping portion 8 of the film laminated in the order of the outer layer 2, the adhesive layer 4, and the inner layer 6 from the top, and FIGS. 3 and 4 show the outer layer 2, the adhesive layer 4, FIG. 3 is a cross-sectional view in the vicinity of an overlapping portion 8 of a film in which an inner layer, an adhesive layer 4 and an outer layer 2 are laminated in this order. Moreover, (a) is drawing which shows the state before heat processing among each drawing, (b) shows the state which produced the shift | offset | difference between the outer layer of a film or an outer layer, and an adhesion layer, and an inner layer in the overlap part after heat processing. It is a drawing. 5A shows a film piece 100 obtained by cutting the laminated film of the present invention into a rectangle having a size of 165 mm in the take-up direction (MD) and 235 mm in the perpendicular direction (TD), and FIG. 5B shows the film piece. On a laminated film in which 100 is sealed so that the outer layer surface on one end side A in the take-up direction (MD) and the inner layer surface or outer layer surface on the other end side B in the take-up direction (MD) are parallel to the take-up direction (MD) It is drawing explaining the state which formed the superimposition part 8 of 2-7 mm width in this.

  As shown in FIG. 5, the laminated film of the present invention cuts out a rectangular film of 165 mm in the take-up direction (MD) and 235 mm in the perpendicular direction (TD) from the manufactured film roll to form a film piece 100. Next, the surface of the outer layer 2 on one end side A of the MD of the film piece 100 and the inner layer surface or outer layer surface on the other end side B are sealed so as to be parallel to the MD, and overlapped with a width of 2 to 7 mm on the laminated film. A mating portion 8 is formed and heat treatment is performed at 90 ° C. In the present invention, “heat-treating at 90 ° C.” means a state of treatment for 5 seconds in 90 ° C. hot water, silicon oil, or hot air.

  When the film is returned to room temperature after the heat treatment at 90 ° C., the laminated film of the present invention has the MD end surface 10 of the outer layer 2 or the MD end surfaces 10 and 12 of the outer layer 2 and the adhesive layer 4 sealed with the overlapping portion 8. The displacement width 18w of the displacement 18 between the MD end surfaces 12 and 14 of the adhesive layer 2 and the inner layer 4 or the end surface 14 of the inner layer 6 is within 5% of the overlap width 8w of the overlap portion 8.

  FIG. 1 is an example of a three-layer / three-layer film having an adhesive layer 4 between an outer layer 2 and an inner layer 6. When the laminated film piece 100 of the present invention is heat-treated at 90 ° C. and then returned to normal temperature, the end surface 10 in the take-off direction (MD) of the outer layer sealed by the overlapping portion 8, the adhesive layer 4, and the inner layer 6 The state which the gap | deviation 18 produced between the end surfaces 12 and 14 of the taking-off direction (MD) is shown. In this case, the deviation width 18 is within 5% of the overlapping width 8 w of the overlapping portion 8.

  FIG. 2 is an example of three types and three layers, similar to FIG. 1, and the take-off direction (MD) of the outer layer 2 and the adhesive layer 4 sealed by the overlapping portion 8 when the temperature is returned to room temperature after the heat treatment. This shows a state in which a deviation 18 is generated between the end surfaces 10 and 12 of the inner layer 6 and the end surface 14 of the inner layer 6 in the take-up direction (MD). Even in this case, the deviation width 18 is within 5% of the overlapping width 8w of the overlapping portion 8.

  3 and 4 show examples of three types and five layers of the outer layer 2, the adhesive layer 4, the inner layer 6, the adhesive layer 4, and the outer layer. FIG. 3 shows the end surface 10 in the take-off direction (MD) of the outer layer 2 sealed by the overlapping portion 8 and the adhesive layer 4, the inner layer 6, the adhesive layer 4, and the outer layer 6 when the temperature is returned to room temperature after the heat treatment. This shows a state in which a deviation 18 has occurred between the end faces 12, 14, 12, and 10 in the take-up direction (MD). FIG. 4 shows the end surfaces 10 and 12 in the take-off direction (MD) of the outer layer 2 and the adhesive layer 4 sealed by the overlapping portion 8 when the temperature is returned to room temperature after the heat treatment, the inner layer 6, the adhesive layer 4, The state which the gap | deviation 18 produced between the end surfaces 14, 12, and 10 of the taking-out direction (MD) of the outer layer 6 is shown. Even in these cases, the deviation width 18 is within 5% of the overlapping width 8w of the overlapping portion 8.

  When a laminated film having an outer layer made of a conventional polyester resin is subjected to heat treatment, a phenomenon of peeling between the outer layer and the adhesive layer or between the adhesive layer and the inner layer is observed, and a good appearance is obtained. There was a problem that it was not possible. On the other hand, the laminated film of the present invention hardly peels between the outer layer and the adhesive layer or between the adhesive layer and the inner layer even when heat treatment is performed, and an excellent appearance is obtained.

  In the laminated film of the present invention, the ease of peeling can be expressed by a shift generated between the outer layer and the adhesive layer after sealing or between the adhesive layer and the inner layer. That is, in the laminated film of the present invention, after the heat treatment at 90 ° C., when the temperature is returned to normal temperature, the end surface of the outer layer taken in the overlap direction (MD) or the take-off direction of the outer layer and the adhesive layer ( The deviation width between the end face of MD) and the end face of the adhesive layer and the inner layer in the take-up direction (MD) or the end face of the inner layer in the take-up direction (MD) is within 5% with respect to the overlap width of the overlapping portion, preferably It is within 3%, more preferably within 2%. If the deviation in the overlapped portion after the heat treatment is within 5%, there is no separation between the one outer layer and the adhesive layer or the adhesive layer and the inner layer even after the heat treatment, and an excellent appearance can be maintained.

  The overlapping portion seals the outer layer surface on one end side in the take-up direction (MD) and the inner layer surface or outer layer surface on the other end side in the take-up direction (MD) so as to be parallel to the take-up direction (MD). It is a part formed by overlapping the laminated film with a width of 2 to 7 mm. Solvents used for sealing the outer layer on one end and the inner layer or outer layer on the other end include pentane, n-hexane, diethyl ether, heptane, octane, cyclohexane, isopropyl acetate, acetic acid-n-butyl, acetic acid- n-propyl, carbon tetrachloride, xylene, ethyl acetate, toluene, benzene, methyl methyl ketone, methyl acetate, methylene chloride, tetrahydrofuran, dioxolane, acetone, isopropanol, ethanol, methanol, or at least two of these solvents Can be mentioned. Further, the seal width is at least 2 mm width or more, preferably 3 mm width or more, 7 mm width or less, preferably 5 mm or less.

<Layer structure of film>
The laminated film of the present invention is not particularly limited as long as it has at least three layers having an adhesive layer (AD layer) between the outer layer (S layer) and the inner layer (M layer). Here, the inner layer (M layer) may be a single layer or multiple layers, and in the case of multiple layers, it may have the same layer as the outer layer (S layer).

  A preferred laminated structure in the present invention is a five-layer structure comprising outer layer (S layer) / adhesive layer (AD layer) / inner layer (M layer) / adhesive layer (AD layer) / surface layer (S layer). By adopting a layer structure, it is possible to obtain a laminated film that has both excellent heat resistance and appearance, which are the objects of the present invention, and that does not easily peel off even when processed at high temperatures.

Next, (S layer) / (AD layer) / (M layer) / consisting of an outer layer (S layer), an inner layer (M layer), and an adhesive layer (AD layer), which is one of the preferred embodiments of the present invention. A film having a five-layer structure of (AD layer) / (S layer) will be described.
The thickness ratio of each layer may be set in consideration of the effects and functions described above, and is not particularly limited. In the present invention, the thickness ratio of the outer layer (S layer) to the thickness of the entire film is 10% or more, preferably 20% or more, and the upper limit is 75%, preferably 65% or less. The thickness ratio of the inner layer (M layer) to the thickness of the entire film is 20% or more, preferably 30% or more, and the upper limit is 80% or less, preferably 70% or less. Furthermore, the adhesive layer (AD layer) is 0.5 μm or more, preferably 1 μm or more, and 6 μm or less, preferably 5 μm or less in view of its function. When the thickness of each layer is within the above range, a laminated film that is excellent in heat resistance and appearance and hardly peels after being treated at a high temperature can be obtained.

  The thickness of the laminated film of the present invention is not particularly limited, but is usually 20 μm or more, preferably 30 μm or more, and 70 μm or less, preferably 60 μm or less. Here, if the thickness is 20 μm or more, the film is easy to handle. On the other hand, if it is 60 μm or less, the transparency and shrinkage workability are excellent, which is economically preferable. If necessary, surface treatment and surface processing such as corona treatment, printing, coating, and vapor deposition, and bag making processing and perforation processing using various solvents and heat sealing can be performed.

  For example, when the film having a thickness of 50 μm is measured in accordance with Japanese Industrial Standard JIS K7105, the haze value is preferably 10% or less, more preferably 7% or less. Preferably, it is more preferably 5% or less. If the haze value is 10% or less, the transparency of the film can be obtained and a display effect can be obtained.

  Moreover, the laminated film of the present invention is 30% by mass or less, preferably 25% by mass or less, more preferably 20% by mass or less, based on the total amount of resin constituting each layer in the outer layer, inner layer, and adhesive layer, preferably the inner layer. Even when the film is regenerated and added in the above range, the haze value when a film having a thickness of 50 μm is measured according to JIS K7105 is 10% or less, preferably 7% or less, more preferably 5% or less. preferable. If the haze value after regeneration addition is 10% or less, good transparency in the regeneration film can be maintained.

<Application>
The laminated film of the present invention can be suitably used as a stretched film because the tensile strength and impact strength are increased by stretching. Moreover, it can also be used as a heat-shrinkable film by adjusting the heat setting temperature after stretching. In addition, it can be suitably used for various molded products.

Next, the case where the laminated film of the present invention is used as a heat shrinkable film will be described.
The polyester resin constituting the outer layer imparts rigidity and rupture resistance to the film, and can suppress natural shrinkage while imparting low temperature shrinkage. However, polyester-based heat-shrinkable film does not provide uniform shrinkage, so shrinkage in the shrinkage finish, such as uneven shrinkage, and label applications, etc. cause shrinkage in the direction perpendicular to the main shrinkage direction, resulting in poor appearance. Cause problems. Therefore, the above-mentioned problem can be solved by configuring the outer layer as a main component with a polyester resin and the inner layer with a thermoplastic resin. That is, by making the inner layer as a main component with polystyrene resin, shrink finish that was difficult to solve with polyester resin alone, and heat shrinkage in the direction perpendicular to the main shrinkage direction mainly in label applications are suppressed. As a result, it is possible to improve shrinkage finishing properties while having rigidity, rupture resistance, and low natural shrinkage.

When the laminated film of the present invention is a heat shrinkable film, the heat shrinkage rate in the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds is 10% or more, preferably 20% or more, more preferably 30% or more. And 75% or less, preferably 70% or less, preferably 65% or less. Further, the heat shrinkage rate in the main shrinkage direction when immersed in warm water at 70 ° C. for 10 seconds is 5% or more, preferably 10% or more, more preferably 15% or more, 40% or less, preferably 35% or less. It is desirable to be.
In addition, the “main shrinkage direction” means a direction having a large thermal shrinkage rate in the longitudinal direction (longitudinal direction) of the film and the transverse direction (width direction) of the film. The direction corresponding to the direction is meant, and the “orthogonal direction” means a direction perpendicular to the main contraction direction.

  The heat shrinkage rate at the above temperature is an index for determining adaptability to a shrinking process in a relatively short time (several seconds to about several tens of seconds) such as for use as a shrinkage label for a PET bottle. For example, the required shrinkage rate required for a heat-shrinkable film applied to the use of shrinkage labels for PET bottles varies depending on the shape, but is generally about 20% to 70%.

  Further, the shrinkage processing machine that is most commonly used industrially for label mounting of PET bottles is generally called a steam shrinker that uses steam as a heating medium for shrinking. Furthermore, the heat-shrinkable film needs to be sufficiently heat-shrinked at a temperature as low as possible from the viewpoint of the influence of heat on the object to be coated. However, in the case of a film that is highly temperature dependent and has an extremely different shrinkage ratio depending on the temperature, parts with different shrinkage behavior are likely to occur due to temperature spots in the steam shrinker, so shrinkage spots, wrinkles, avatars, etc. occur. The shrink-finished appearance tends to be poor. From the viewpoint of including these industrial productivity, if the film has a thermal shrinkage rate within the above range, it can sufficiently adhere to the object to be coated within the shrinkage processing time, and shrinkage spots, wrinkles and avatars will not be generated. It is preferable because a good shrink finish appearance can be obtained.

  When the laminated film of the present invention is used as a heat-shrinkable label, the shrinkage in the vertical direction (perpendicular to the main shrinkage direction) is 10% or less when heated in 80 ° C. warm water for 10 seconds. Preferably, it is preferably 5% or less, more preferably 3% or less, and preferably 10% or less when heated in 70 ° C. warm water for 10 seconds. It is more preferable that it is 3% or less. Here, if the film has a heat shrinkage rate of 10% or less in the direction orthogonal to the main shrinkage direction, the dimension itself in the direction orthogonal to the main shrinkage direction after shrinkage is shortened, or the printed pattern or character after shrinkage is shortened. This is preferable because distortion is likely to occur, and in the case of a square bottle, troubles such as vertical sink are unlikely to occur.

  When the laminated film of the present invention is used as a heat-shrinkable film, the tensile elastic modulus in the direction orthogonal to the main shrinkage direction of the film is preferably 1,300 MPa or more, and 1,400 MPa or more from the viewpoint of rigidity. More preferably. Moreover, the upper limit of the tensile elastic modulus of the heat-shrinkable film that is usually used is about 3,000 MPa, preferably about 2,900 MPa, and more preferably about 2,800 MPa. If the tensile modulus in the direction perpendicular to the main shrinkage direction of the film is 1,300 MPa or more, the rigidity of the entire film can be increased, and even when the thickness of the film is reduced, a container such as a PET bottle When a film made in a bag is covered with a labeling machine or the like, it is preferable that problems such as covering at an angle or a decrease in yield due to film folding or the like are unlikely to occur. In addition, it is preferable that the average value of the tensile elasticity modulus about MD and orthogonal direction (TD) of each film is 1,500 Mpa or more, and it is further more preferable that it is 1,700 Mpa or more. The tensile elastic modulus can be measured under the condition of 23 ° C. according to Japanese Industrial Standard JIS K7127.

  Further, the tensile elastic modulus in the film main shrinkage direction is not particularly limited as long as the film has low stiffness, but it is 1,500 MPa or more, preferably 2,000 MPa or more, more preferably 2,500 MPa or more, and the upper limit is 6 1,000 MPa or less, preferably 4,500 MPa or less, more preferably 3,500 MPa or less. By setting the tensile elastic modulus in the main shrinkage direction of the film within the above range, it is preferable because the strength of the film can be enhanced in both directions.

  When the laminated film of the present invention is used as a heat-shrinkable film, the natural shrinkage rate is desirably as small as possible. However, it is generally desirable that the heat shrinkable film has a natural shrinkage rate of 1.5% or less, preferably 1.0% or less after being stored at 30 ° C. for 30 days, for example. If the natural shrinkage rate under the above conditions is 1.5% or less, even if the produced film is stored for a long period of time, it can be stably attached to a container or the like, and it is difficult to cause problems in practice.

  When the laminated film of the present invention is used as a heat-shrinkable film, the rupture resistance is evaluated by a tensile rupture elongation, and in a tensile rupture test under an environment of 0 ° C., particularly in a label application, a film take-off (flow) direction ( MD) has an elongation of 100% or more, preferably 200% or more, more preferably 300% or more. If the tensile elongation at break in an environment of 0 ° C. is 100% or more, it is difficult to cause problems such as breakage of the film at the time of printing / bag making and the like, which is preferable. Further, even when the tension applied to the film increases as the speed of processes such as printing and bag making increases, it is more preferable that the tensile elongation at break is 200% or more, so that it is difficult to break.

  The seal strength when the laminated film of the present invention is used as a heat-shrinkable film is determined by the measurement method described in the examples described later (test speed in the TD direction by the T-type peeling method in an environment of 23 ° C. and 50% RH). 3N / 15 mm width or more, preferably 5 N / 15 mm width or more, more preferably 7 N / 15 mm width or more using a method of peeling at 200 mm / min. The upper limit of the delamination strength is not particularly limited, but is preferably about 15 N / 15 mm width from the viewpoint of solvent resistance on the film surface.

  Since the laminated film of the present invention has a seal strength of at least 3 N / 15 mm width, troubles such as peeling of the seal portion during use do not occur. Moreover, the delamination strength after heat shrinking the laminated film of the present invention is also good, and the strength equivalent to the delamination strength before the heat shrinkage can be maintained.

  When the laminated film of the present invention is a heat-shrinkable film, it is processed from a flat shape to a cylindrical shape or the like by a packaged object and provided for packaging. For things that require printing in cylindrical containers such as PET bottles, first print the required image on one side of a wide flat film wound up on a roll, and then cut the printed image to the required width. The center seal (the so-called envelope is attached to the seal portion) may be folded into an inner side to form a cylinder. As the center sealing method, an organic solvent bonding method, a heat sealing method, an adhesive method, and an impulse sealer method can be considered. Among these, from the viewpoint of productivity and appearance, an adhesion method using an organic solvent is preferably used.

<Method for producing laminated film>
The laminated film of the present invention can be produced by a known method. The form of the film may be either flat or tube-like, but the flat form is preferable in terms of productivity (a few products can be taken in the width direction of the original film) and printing on the inner surface. . As a method for producing a flat film, for example, a resin is melted by using a plurality of extruders, co-extruded from a T die, solidified by cooling with a chilled roll, roll-stretched in the vertical direction, and tenter-stretched in the horizontal direction. An example is a method of obtaining a film by winding, annealing, cooling, and winding with a winder (corona discharge treatment is applied to the surface when printing is performed). Moreover, the method of cutting open the film manufactured by the tubular method and making it flat is also applicable. Alternatively, the resin constituting the inner layer and the resin constituting the outer layer may be separately formed and then laminated using a press method, a roll nip method, or the like.

  The melt-extruded resin is cooled with a cooling roll, air, water, etc., and then reheated by an appropriate method such as hot air, hot water, infrared rays, etc., and 1 by a roll method, a tenter method, a tubular method, etc. It can be stretched biaxially or biaxially.

  Even in the case of applications that require shrinkage characteristics in a substantially uniaxial direction, such as heat shrinkable labels for PET bottles, it is also effective to stretch the film in a range that does not impair the shrinkage characteristics in the vertical direction. The stretching temperature is typically 80 ° C. or higher and 110 ° C. or lower, although it depends on the laminated structure and compounded resin. Furthermore, although the rupture resistance is improved as the draw ratio is increased, the shrinkage ratio is increased accordingly, and it is difficult to obtain a good shrinkage finish. Is highly preferred.

[Molded products, heat-shrinkable labels and containers]
Since the laminated film of the present invention is excellent in heat resistance, appearance characteristics, transparency, etc., its use is not particularly limited, but a printing layer, a vapor deposition layer and other functional layers are formed as necessary. Can be used as various molded products used in bottles (blow bottles), trays, lunch boxes, prepared food containers, dairy products containers, and the like. In particular, when the laminated film of the present invention is used as a heat-shrinkable label for food containers (for example, PET bottles, glass bottles, preferably PET bottles for soft drinks or foods), a complicated shape (for example, a cylinder with a constricted center, Even a square column, pentagonal column, hexagonal column or the like having a square shape can be adhered to the shape, and a container with a beautiful label without wrinkles or avatars can be obtained. The molded article and container of the present invention can be produced by using a normal molding method.

  Since the laminated film of the present invention has excellent heat resistance and appearance, in addition to the heat-shrinkable label material of a plastic molded product that deforms when heated to a high temperature, the coefficient of thermal expansion, water absorption, etc. Material very different from shrinkable film, for example, polyolefin resin such as metal, porcelain, glass, paper, polyethylene, polypropylene, polybutene, polyester resin such as polymethacrylate resin, polycarbonate resin, polyethylene terephthalate, polybutylene terephthalate It can be suitably used as a heat-shrinkable label material for a package (container) using at least one selected from a resin and a polyamide-based resin as a constituent material.

  As a material constituting the plastic packaging body in which the laminated film of the present invention can be used, polystyrene, rubber-modified impact-resistant polystyrene (HIPS), styrene-butyl acrylate copolymer, styrene-acrylonitrile copolymer in addition to the above-mentioned resins. , Styrene-maleic anhydride copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), methacrylate-butadiene-styrene copolymer (MBS), polyvinyl chloride resin, phenol resin, urea resin, melamine resin , Epoxy resin, unsaturated polyester resin, silicone resin and the like. These plastic packages may be a mixture of two or more resins or a laminate.

  Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the take-up (flow) direction of the laminated film is described as MD (Machine Direction), and the perpendicular direction thereof is described as TD (Transverse Direction).

[Evaluation method]
(1) Measurement of shrinkage rate The obtained film was cut into a size of MD100 mm and TD100 mm, and this sample was immersed in a hot water bath at 80 ° C. for 10 seconds, and then immersed in cold water at 23 ° C. for 30 seconds. A) was measured, and the shrinkage was calculated by the following equation (1).
Shrinkage rate (%) = 100 × (100−A) / 100 (1)

(2) Storage elastic modulus (E ')
The obtained film was cut into a size of TD 4 mm and MD 60 mm to prepare a sample. Using a viscoelastic spectrometer DVA-200 (produced by IT Measurement Co., Ltd.), the measurement temperature was 10 Hz, the strain was 0.1%, the heating rate was 3 ° C./min, and the chuck was 2.5 cm. The dynamic viscoelasticity was measured for MD in the range of −150 ° C. to 150 ° C.

(3) Peeling evaluation The obtained film was slit to 235 mm width in TD, 10 mm of both ends of TD were piled up with the bag making machine, and the film end surface was sealed with various solvents at 4 mm width, and the cylindrical film was produced. This cylindrical film is cut into MD (direction perpendicular to the TD direction) to 165 mm, attached to a cylindrical plastic bottle with a capacity of 500 mL, and rotated in a contraction tunnel of 3.2 m (3 zones) in the steam heating system. Without passing, it was allowed to pass in about 5 seconds. The atmospheric temperature in the tunnel in each zone was set to a range of 70 to 105 ° C. by adjusting the amount of steam with a steam valve. After film coating, the following criteria were used for evaluation.
(Double-circle): The shift | offset | difference width in the end surface of a mounting label is 0% or more and less than 2% with respect to the overlap width of the overlapping part of a film.
A: The deviation width at the end face of the mounting label is 2% or more and 5% or less with respect to the overlapping width of the overlapping portion of the film.
X: The deviation width at the end face of the mounting label is larger than 5% with respect to the overlapping width of the overlapping portion of the film, and the outer layer and the inner layer of the mounting label are separated.

Example 1
As a resin composition used in the outer layer, polylactic acid “NatureWorks4060” (manufactured by NatureWorks, D-form ratio 12%; hereinafter referred to as “S-1”) is 60% by mass, polylactic acid “NatureWorks4042” (manufactured by NatureWorks, D body ratio 4.25%; hereinafter referred to as “S-2”) 30% by mass, and lactic acid copolymer “Plamate PD-150” (Dainippon Ink Co., Ltd .; hereinafter referred to as “S-3”) .) Was mixed by 10% by mass and kneaded with a twin screw extruder to produce mixed resin composition pellets (hereinafter referred to as “mixed resin composition A1”).
As a resin composition used in the adhesive layer, a styrene-vinylisoprene block copolymer elastomer “HIBLER 7125” (manufactured by Kuraray Co., Ltd., SIS hydrogenated product; hereinafter referred to as “AD-1”) 30% by mass, and styrene-butadiene Block copolymer (mass ratio of styrene unit to butadiene unit: styrene / butadiene = 82/18, storage elastic modulus E ′ (0 ° C.): 1.44 × 10 ⁹ Pa, peak temperature of loss elastic modulus E ″: − 84 ° C., 200 ° C., MFR at a load of 49 N = 6.8 g / 10 minutes; hereinafter referred to as “AD-2”) 70% by mass are mixed and kneaded by a twin screw extruder, and the mixed resin composition pellets are mixed. This was prepared (hereinafter referred to as “mixed resin composition B1”).
As the resin composition used in the inner layer, 45% by mass of polyethylene resin “Umerit 0540F” (manufactured by Ube Industries; hereinafter referred to as “M-1”) and polypropylene resin “Nobrene FH3315” (manufactured by Sumitomo Chemical Co., Ltd .; hereinafter referred to as “M”) -2 ") 32% by mass, and hydrogenated petroleum resin" Alcon P125 "(manufactured by Arakawa Chemical; hereinafter referred to as" M-3 ") 14% by mass, mixed resin composition A1: 8% by mass, mixed Resin composition B1: An ethylene-methacrylic acid-glycidyl methacrylate copolymer “bond first 7M” (manufactured by Sumitomo Chemical Co., Ltd .; hereinafter referred to as “C-1”) with respect to 100 parts by mass of the mixed resin composition composed of 1% by mass. ) And modified styrene-ethylene / butylene-styrene block copolymer “Dynalon 8630P” (manufactured by JSR; hereinafter referred to as “C-2”). Mixed resin mixture 2 parts by weight of the resin composition obtained by blending (hereinafter, referred to as. "Resin composition C1") were kneaded by a twin-screw extruder, to prepare a mixed resin composition pellets.
Each resin is extruded from three extruders using the mixed resin composition A1, the mixed resin composition B1, and the mixed resin composition C1, and the mixed resin composition A1 and the mixed resin composition B1 each have two flow paths. And laminated again in a five-layer die, outer layer (mixed resin composition A1) / adhesive layer (mixed resin composition B1) / inner layer (mixed resin composition C1) / adhesive layer (mixed resin composition) A non-stretched film in which the thickness of each layer was 30 μm / 5 μm / 180 μm / 5 μm / 30 μm was obtained by closely adhering a five-layer laminated sheet composed of B1) / outer layer (mixed resin composition A1) to a roll at 50 ° C.
Next, the unstretched film was cut into a size of 165 mm × 235 mm, and a solvent (hereinafter referred to as “solvent 1”) in which acetone / ethanol was mixed in half at a volume fraction was applied to both ends, and the outer layers were overlapped. After forming an overlapped portion (seal width: 4 mm), observation was performed by immersing in 90 ° C. warm water for 5 seconds.
As a result, even after the boil treatment, the outer layer and the inner layer of the unstretched film 1 were not peeled off, and the deviation width of both layers in the seal portion was 0.5% of the overlap width, maintaining an excellent appearance. Thereby, the applicability of the laminated film 1 as a food packaging application could be confirmed.

(Example 2)
The unstretched film in Example 1 was stretched 5.0 times in the transverse uniaxial direction at a preheating temperature of 80 ° C. and a stretching temperature of 78 ° C. using a film tenter manufactured by Kyoto Machine Co., Ltd., and then heat-treated at 90 ° C. to a thickness of 50 μm. A heat-shrinkable laminated film was obtained.
The obtained heat-shrinkable laminated film was slit to TD with a width of 235 mm, both ends in the width direction were overlapped by 10 mm with a bag making machine, and the film end face was sealed with various solvents to a seal width of 4 mm to prepare a cylindrical film. . This cylindrical film was cut into MD with a width of 165 mm, attached to a cylindrical plastic bottle with a capacity of 500 mL, and heat-shrinkable laminated by heat treatment for 5 seconds at a temperature of 90 ° C. via a steam shrinker. A bottle fitted with a film was obtained.
When the overlapping part of the heat-shrinkable laminated film after the heat-shrinking step was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width of both layers was 0.5% of the overlapping width. Moreover, the shrinkage rate at 80 ° C. of the heat-shrinkable laminated film was 30%. Thereby, the use possibility as a heat-shrinkable label of the heat-shrinkable laminated film of a present Example has been confirmed.

(Example 3)
Non-stretching by the same method as in Example 1 except that the resin composition used in the adhesive layer of the unstretched film in Example 1 was changed to AD-1: 80% by mass and AD-2: 20% by mass. A film was prepared. This unstretched film was stretched by the same method as in Example 2 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged by the same method as in Example 2, and then a label was attached with a shrinker. When the seal part of the heat-shrinkable laminated film after the heat shrinking process was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width was 4% of the overlap width. Moreover, the shrinkage rate at 80 ° C. of this heat-shrinkable laminated film was 30%. From this, the applicability as a heat-shrinkable label of the heat-shrinkable laminated film of this example could be confirmed.

Example 4
Polyethylene terephthalate “S2008” (hereinafter referred to as “S-4”) is used as the resin composition used in the outer layer, and styrene-vinylisoprene block copolymer elastomer “HIBLER” is used as the resin composition used in the adhesive layer. 5125 ”(manufactured by Kuraray Co., Ltd., SIS; hereinafter referred to as“ AD-3 ”) 40% by mass and AD-2: 60% by mass were mixed and kneaded with a twin screw extruder to prepare a mixed resin composition pellet. (Hereinafter referred to as “mixed resin composition B2”). Moreover, as a resin composition used in the inner layer, a styrene-butadiene copolymer (mass ratio of styrene unit to butadiene unit: styrene / butadiene = 90/10, storage elastic modulus (E ′) at 0 ° C .: 3.15 × 10 ⁹ Pa, peak temperature of loss elastic modulus E ″: 55 ° C .; hereinafter referred to as “M-4”) 40% by mass, styrene-butadiene copolymer (styrene / butadiene = 76/24 (% by mass), 0 ° C. Storage elastic modulus (E ′): 6.89 × 10 ⁸ Pa, peak temperature of loss elastic modulus E ″: −74 ° C., MFR: 6.8 g / 10 min; hereinafter referred to as “M-5”) 60 mass % Were mixed and kneaded with a twin screw extruder to produce mixed resin composition pellets (hereinafter referred to as “mixed resin composition C2”).
Each resin is extruded from three extruders using the resin composition S-4, the mixed resin composition B2, and the mixed resin composition C2, and each of the resin composition S-4 and the mixed resin composition B2 has two flows. Separated into roads and laminated again in a five-layer die, outer layer (S-4) / adhesive layer (mixed resin composition B2) / inner layer (mixed resin composition C2) / adhesive layer (mixed resin composition B2) ) / Outer layer (S-4) 5 layer laminated sheet was adhered to a roll at 50 ° C. to obtain an unstretched film in which the thickness of each layer was 30 μm / 10 μm / 120 μm / 10 μm / 30 μm. This unstretched film was stretched 5.0 times in the transverse uniaxial direction at a preheating temperature of 80 ° C. and a stretching temperature of 78 ° C. by a film tenter manufactured by Kyoto Machine Co., Ltd., and then heat-treated at 90 ° C. to give a heat shrinkage of 50 μm thickness. The laminated film was obtained.
The obtained heat-shrinkable laminated film was sealed in the same manner as in Example 2 and heat-shrinked with a shrinker to obtain a bottle equipped with the heat-shrinked film. When the overlapping portion of the film after the heat shrinking step was confirmed, there was no peeling between the outer layer and the inner layer, and the deviation width in the overlapping portion was 1.6% of the overlapping width. The shrinkage at 80 ° C. was 50%. From this, the applicability as a heat-shrinkable label of the heat-shrinkable laminated film of this example could be confirmed.

(Example 5)
As a resin composition used in the inner layer, a mixed resin composition obtained by kneading M-1: 50% by mass, M-2: 35% by mass, and M-3: 15% by mass with a twin screw extruder is used. An unstretched film was produced in the same manner as in Example 1 except that. This unstretched film was stretched 5.0 times in the transverse uniaxial direction at a preheating temperature of 80 ° C and a stretching temperature of 75 ° C by a film tenter manufactured by Kyoto Machine Co., Ltd. The laminated film was obtained. The heat-shrinkable laminated film was labeled with a shrinker after bag making in the same manner as in Example 2. When the seal part of the heat-shrinkable laminated film after the heat shrinking step was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width of the overlapping part was 0.4% of the overlapping width. Moreover, the shrinkage rate at 80 ° C. of the heat-shrinkable laminated film was 40%. From this, the applicability as a heat-shrinkable label of the heat-shrinkable laminated film of this example could be confirmed.

(Example 6)
Non-stretching by the same method as in Example 5 except that the resin composition used in the adhesive layer of the unstretched film in Example 5 was changed to AD-1: 50 mass% and AD-2: 50 mass%. A film was prepared. This unstretched film was stretched by the same method as in Example 5 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged by the same method as in Example 2, and then a label was attached with a shrinker. When the seal part of the film after the heat shrinking process was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width of the overlapping part was 3.5% of the overlapping width. Moreover, the shrinkage rate at 80 ° C. of the heat-shrinkable laminated film was 40%. From this, the applicability as a heat-shrinkable label of the heat-shrinkable laminated film of this example could be confirmed.

(Example 7)
Example 5 except that the resin composition used in the outer layer of the unstretched film in Example 5 was changed to S-1: 40% by mass, S-2: 50% by mass, and S-3: 10% by mass. A non-stretched film was produced by the same method as described above. This unstretched film was stretched by the same method as in Example 5 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged by the same method as in Example 2, and then a label was attached with a shrinker. When the seal part of the heat-shrinkable laminated film after the heat shrinking step was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width of the overlapping part was 3.5% of the overlapping width. Moreover, the shrinkage rate at 80 ° C. of the heat-shrinkable laminated film was 40%. This confirmed the possibility of using the heat-shrinkable laminated film as a heat-shrinkable label.

(Example 8)
As a resin composition used in the inner layer, M-1: 43% by mass, M-2: 31% by mass, and M-3: 11% by mass, mixed resin composition A1: 12% by mass, mixed resin composition B1: For 100 parts by mass of the mixed resin composition consisting of 1% by mass, ethylene-ethyl acrylate-methyl methacrylate graft copolymer, trade name “Modiper A5200” (manufactured by NOF Corporation; hereinafter referred to as “C-3 And Example 2 except that a mixed resin composition obtained by kneading a resin composition obtained by mixing 2 parts by mass of a resin mixture obtained by mixing each of C-2 and C-2 by a twin screw extruder was used. An unstretched film was produced by the same method. This unstretched film was stretched by the same method as in Example 5 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged by the same method as in Example 2, and then a label was attached with a shrinker. When the seal part of the heat-shrinkable laminated film after the heat shrinking step was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width of the overlapping part was 0.2% of the overlapping width. Moreover, the shrinkage rate at 80 ° C. of the heat-shrinkable laminated film was 40%. From this, the applicability as a heat-shrinkable label of the heat-shrinkable laminated film of this example could be confirmed.

( Reference Example 1 )
The resin composition used in the adhesive layer of the unstretched film in Example 4 was changed to a polyester elastomer, trade name “Primalloy B1900NS” (Mitsubishi Chemical Corporation; hereinafter referred to as “AD-5”). A non-stretched film was produced in the same manner as in Example 4. This unstretched film was stretched by the same method as in Example 4 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged in the same manner as in Example 4 and then attached with a shrinker label. When the seal part of the heat-shrinkable laminated film after the heat shrinking step was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width of the overlapping part was 0.1% or less of the overlapping width. Moreover, the shrinkage rate at 80 ° C. of the heat-shrinkable laminated film was 50%. From this, the applicability as a heat-shrinkable label of the heat-shrinkable laminated film of this example could be confirmed.

( Reference Example 2 )
The resin composition used in the adhesive layer of the unstretched film in Example 4 was changed to a polyester elastomer, trade name “Primalloy B1910N” (manufactured by Mitsubishi Chemical Corporation; hereinafter referred to as “AD-6”). A non-stretched film was produced in the same manner as in Example 4. This unstretched film was stretched by the same method as in Example 4 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged in the same manner as in Example 4 and then attached with a shrinker label. When the seal part of the heat-shrinkable laminated film after the heat shrinking step was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width of the overlapping part was 0.1% or less of the overlapping width. Moreover, the shrinkage rate at 80 ° C. of the heat-shrinkable laminated film was 50%. From this, the applicability as a heat-shrinkable label of the heat-shrinkable laminated film of this example could be confirmed.

( Reference Example 3 )
The resin composition used in the adhesive layer of the unstretched film in Example 4 is AD-5: 70% by mass, polyester elastomer, trade name “Primalloy A1800NS” (Mitsubishi Chemical Corporation; hereinafter referred to as “AD-7”). An unstretched film was produced in the same manner as in Example 4 except that the content was changed to 30% by mass. This unstretched film was stretched by the same method as in Example 4 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged in the same manner as in Example 4 and then attached with a shrinker label. When the seal part of the heat-shrinkable laminated film after the heat-shrinking step was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width of the overlapping part was 2% of the overlapping width. Moreover, the shrinkage rate at 80 ° C. of the heat-shrinkable laminated film was 50%. From this, the applicability as a heat-shrinkable label of the heat-shrinkable laminated film of this example could be confirmed.

( Reference Example 4 )
Except for changing the resin composition used in the adhesive layer of the unstretched film in Example 4 to AD-5: 60% by mass and AD-7: 40% by mass, non-stretched by the same method as in Example 4. A film was prepared. This unstretched film was stretched by the same method as in Example 4 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged in the same manner as in Example 4 and then attached with a shrinker label. When the seal part of the heat-shrinkable laminated film after the heat-shrinking step was confirmed, the outer layer and the inner layer were not peeled off, and the deviation width of the overlapping part was 2.5% of the overlapping width. Moreover, the shrinkage rate at 80 ° C. of the heat-shrinkable laminated film was 50%. This confirmed the possibility of using the heat-shrinkable laminated film as a heat-shrinkable label.

(Comparative Example 1)
An unstretched film was produced in the same manner as the unstretched film 1 except that the resin composition constituting the adhesive layer of the unstretched film 1 of Example 1 was changed to AD-1: 100% by mass. This unstretched film 3 was stretched by the same method as in Example 2 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged by the same method as in Example 2, and then a label was attached with a shrinker. After confirming the seal part of the heat-shrinkable laminated film after the heat-shrinking process, the end faces of the outer layer and the inner layer, which are the solvent-coated surfaces, are displaced, and the film inner layer is symmetrical with respect to the solvent-coated surface. The outer layer (outermost surface) on the opposite side turned up, and the outer layer and inner layer forming the outermost surface were peeled off.

(Comparative Example 2)
An unstretched film was produced in the same manner as in the case of the unstretched film 3, except that the resin composition used in the adhesive layer of the unstretched film 3 in Example 4 was changed to AD-3: 100% by mass. This unstretched film was stretched by the same method as in Example 4 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged in the same manner as in Example 4 and then attached with a shrinker label. When the seal part of the heat-shrinkable laminated film after the heat-shrinking step was confirmed, the phenomenon that the outer layer and the inner layer peeled was confirmed as in Comparative Example 1.

(Comparative Example 3)
The resin composition used in the adhesive layer of the unstretched film in Example 1 is a modified styrene-ethylene / butylene-styrene block copolymer “Dynalon 8630P” (manufactured by JSR, modified SEBS; hereinafter referred to as “AD-4”). A non-stretched film was produced in the same manner as in the case of a non-stretched film except that it was changed to). This unstretched film was stretched by the same method as in Example 2 to obtain a heat-shrinkable laminated film. This heat-shrinkable laminated film was packaged by the same method as in Example 2, and then a label was attached with a shrinker. When the edge part of the film after a heat shrink process was confirmed, the phenomenon in which an outer layer and an inner layer peel was confirmed like the comparative example 1.

  While the present invention has been described in connection with embodiments that are presently the most practical and preferred, the present invention is not limited to the embodiments disclosed herein. Rather, it can be changed as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification, and a laminated film, a molded product, a heat-shrinkable label, and the label with such a change are attached. Such containers should also be understood as being within the scope of the present invention.

It is sectional drawing (the 1) of the superposition part vicinity in the suitable embodiment of the film of this invention. It is sectional drawing (the 2) of the overlapping part vicinity in the preferred embodiment of the film of this invention. It is sectional drawing (the 3) of the overlapping part vicinity in the preferred embodiment of the film of this invention. It is sectional drawing (the 4) of the overlapping part vicinity in the suitable embodiment of the film of this invention. It is explanatory drawing explaining the state which formed the overlap part in the suitable embodiment of the film of this invention.

Explanation of symbols

100 Film piece 2 Outer layer 4 Adhesive layer 6 Inner layer 8 Overlapping part
8w Overlap width 10 End face of outer layer 12 End face of adhesive layer 14 End face of inner layer 16 Seal portion 18 Misalignment
18w Width of deviation A One end B The other end

Claims (9)

An outer layer comprising a resin composition comprising at least one polyester-based resin as a main component; an inner layer comprising a resin composition comprising at least one selected from a polyolefin-based resin and a polystyrene-based resin as a main component; and the outer layer and the inner layer. An adhesive layer made of a resin composition mainly composed of an adhesive resin, and a laminated film,
The adhesive resin is a mixed resin composition obtained by mixing at least two types of copolymers or resins selected from the group consisting of the following (a-1), (a-2) and (a-3).
(A-1) Copolymers of aromatic hydrocarbons and conjugated diene hydrocarbons, hydrogenated products of copolymers of aromatic vinyl hydrocarbons and conjugated diene hydrocarbons, or polar groups on these Introduced copolymer
(A-2) From ethylene monomer units and vinyl acetate, acrylic acid, (meth) acrylic acid, ethyl (meth) acrylate, methyl (meth) acrylic acid, maleic anhydride, and glycidyl (meth) acrylate A copolymer comprising one unit selected from the group consisting of:
(A-3) Modified polyolefin resin
The storage elastic modulus (E ′) in the temperature range from 50 ° C. to 100 ° C. under the conditions of the vibration frequency of 10 Hz and the strain of 0.1% of the resin composition constituting the adhesive layer is 10 MPa or more and 2000 MPa or less,
In the rectangular laminated film having a film take-up direction (MD) size of 165 mm and a perpendicular direction (TD) size of 235 mm, the outer layer surface on one end side of the take-up direction (MD) and the take-off direction (MD) ) Is sealed so that the inner layer surface or the outer layer surface on the other end side is parallel to the take-off direction (MD) to form an overlapping portion having a width of 2 to 7 mm on the laminated film and heat-treated at 90 ° C. When the temperature is returned to room temperature, the end surface of the outer layer sealed in the overlapping portion (MD) or the end surface of the outer layer and the adhesive layer (MD) and the direction of the adhesive layer and the inner layer (MD) ) Or an end face of the inner layer in the take-up direction (MD) is within 5% of the overlap width of the overlap portion. The laminated film according to claim 1, wherein the adhesive resin is a mixed resin composition of (a-1) and (a-2) or (a-1) and (a-3). The adhesive resin has soft aromatic hydrocarbons and conjugated diene hydrocarbons having a loss tangent (tan δ) peak calculated from the ratio of storage elastic modulus and loss elastic modulus near or below normal temperature. Or a hydrogenated product thereof and a copolymer of a hard aromatic hydrocarbon and a conjugated diene hydrocarbon having a storage elastic modulus (E ′) at 50 to 100 ° C. of 100 Mpa or more. The laminated film according to claim 1 or 2, which is a mixed resin composition. A copolymer of the soft aromatic hydrocarbon and conjugated diene hydrocarbon in the mixed resin composition, or a copolymer of the hydrogenated product thereof and the hard aromatic hydrocarbon and conjugated diene hydrocarbon. The laminated film according to claim 3, wherein the mixing ratio of the polymers is 80:20. A stretched film obtained by stretching the laminated film according to any one of claims 1 to 4 in at least one direction. The laminated film according to any one of claims 1 to 4 is stretched in at least one direction, and a thermal shrinkage rate in a film main shrinkage direction when immersed in warm water at 80 ° C for 10 seconds is 20% or more. A heat-shrinkable film. A molded product formed by molding the laminated film according to any one of claims 1 to 4, the stretched film according to claim 5 , or the heat-shrinkable film according to claim 6 . A heat-shrinkable label using the heat-shrinkable film according to claim 6 as a substrate. A container equipped with the heat-shrinkable label according to claim 8 .

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