JP5466016B2 - Laminated body, heat-shrinkable film using the laminated body, heat-shrinkable label, and container equipped with the label - Google Patents

Description

  The present invention relates to a laminate having a layer composed of a resin composition containing a polyester elastomer, and a stretched film, a molded product, a heat-shrinkable film, a heat-shrinkable label, and the label using the laminate. It relates to the attached container. More specifically, the present invention uses a laminate that has excellent heat resistance, transparency, and appearance, and that is not easily peeled off even when processed at a high temperature, and has excellent interlayer adhesion, and the laminate. The present invention relates to a heat-shrinkable film, a heat-shrinkable label, and a container equipped with the label.

Technical background

  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 intermediate layer made of a polystyrene resin. This shrink label is provided so that the intermediate layer made of polystyrene resin is interposed between both outer layers made of polyester resin, so that the shrinkage required for the shrink label and the label can be easily peeled off from the container. In addition, it has a feature that it has excellent cutting properties in perforations. Furthermore, this heat-shrinkable label is characterized by excellent solvent resistance and heat resistance because the intermediate 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, the intermediate layer and the outer layer are peeled off due to film rubbing during transportation of the product after the label is attached, or scratching by a human nail or the like. Had occurred.

Therefore, in such a laminated film, a method of forming an adhesive layer having adhesive performance between the outer layer and the intermediate 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 to solve the above-mentioned problems, and the problem of the present invention is that it has excellent heat resistance, transparency, and appearance, and is not easily peeled off even when processed at high temperatures. It is in providing the laminated body excellent in property.

  Another subject of the present invention is a heat-shrinkable film suitable for uses such as a molded article using the laminated film, a stretched film, shrink-wrapping, shrink-bound packaging, heat-shrinkable label, and the like. Another object is to provide a heat-shrinkable label and a container equipped with the heat-shrinkable label.

The present inventor is an adhesive that is difficult to peel off when a laminate comprising a layer composed of a polyester resin and a layer composed of another thermoplastic resin is processed into a film and subjected to a peel test. As a result of earnestly examining the functional resin, it succeeded in obtaining a laminate capable of solving the problems of the prior art when using a resin composition containing a predetermined polyester elastomer, and completed the present invention. .
That is, an object of the present invention is to provide a resin composition containing a polyester elastomer as a main component, a resin composition containing a modified polyester elastomer as a main component, or a mixed resin composition of these resin compositions. A laminate having at least one layer and a second layer composed of a resin composition containing a polyester resin as a main component, wherein the laminate is stretched in at least one direction to produce a heat-shrinkable film Then, a test piece having a size of 150 mm in the main shrinkage direction and 15 mm in a direction perpendicular to the main shrinkage direction is collected from the heat shrinkable film, and then the second layer is formed from the film end surface in the main shrinkage direction of the test piece. Part is peeled to form a peeled portion on the second layer and a peeled portion is formed on the first layer, and a tensile test is performed between the peeled portion of the second layer and the peeled portion of the first layer. Clamped by the chuck, delamination strength when subjected to 180 degree peel test at a test speed of 100 mm / min with respect to the main shrinkage direction is solved by the laminate, characterized in that it 1N / 15 mm width or more.

  Another object of the present invention is achieved by a stretched film, a molded body, a heat-shrinkable film, a heat-shrinkable label, and a container equipped with the label using the laminate of the present invention.

  The laminate of the present invention contains a first layer composed of a polyester elastomer, a modified polyester elastomer, or a resin composition containing these mixed resin compositions as a main component, and a polyester resin as a main component. And a second layer composed of the resin composition, and when formed into a heat-shrinkable film, the delamination strength between the first layer and the second layer is 1 N / 15 mm width or more. Therefore, according to the present invention, it is possible to obtain a laminate having excellent heat resistance, transparency and appearance, and having excellent interlayer adhesion, which is difficult to peel off even when processed at a high temperature, and a heat shrinkable film. It is possible to provide a laminate suitable for applications such as shrink wrapping, shrink tying wrapping and shrinkage labels, which has excellent heat shrinkage properties and transparency when processed into a sheet.

  Furthermore, if the laminate of the present invention is used, it is possible to provide a heat-shrinkable film, a heat-shrinkable label, and a container equipped with the label that are suitable for applications such as shrink-wrapping, shrink-bound packaging, and shrinkable labels.

  Hereinafter, the laminate, stretched film, molded product, heat-shrinkable film, heat-shrinkable label, and container equipped with the label of the present invention 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 occupies 60% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more and 100% by mass or less of the total components of each layer. It is an ingredient.

[Laminate]
The laminate of the present invention includes a resin composition containing a polyester elastomer as a main component, a resin composition containing a modified polyester elastomer as a main component, or a mixed resin composition of these resin compositions. And at least a second layer composed of a resin composition containing a polyester-based resin as a main component.

<First layer>
The first layer of the laminate of the present invention is a resin composition containing a polyester elastomer, a resin composition containing a modified polyester elastomer obtained by modifying a polyester elastomer with a modifier having a polar group, or a mixture thereof. It is comprised with the resin composition which has a resin composition as a main component. A resin composition containing a polyester elastomer as a main component constituting the first layer, a resin containing a modified polyester elastomer as a main component, or a resin composition containing a mixed resin composition of these resins as a main component is used. This makes it possible to suppress delamination due to the adhesive strength peculiar to the elastomer, and provides a stronger delamination force due to the affinity between the polyester component constituting the polyester elastomer and the polyester resin constituting the second layer. Can be granted.

  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 modified polyester elastomer is, for example, one obtained by modifying the polyester elastomer 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. Examples of the modified polyester elastomer include those obtained by modifying a polyester elastomer resin composed of the above segments with a modifier having a polar group.

  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 weight (mass) average molecular weight of the polybutylene terephthalate unit and the like constituting the hard segment of the polyester 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 or less. If the weight (mass) average molecular weight of the hard segment is in the range of 400 to 10,000, the heat resistance of the polyester-based elastomer can be maintained, without causing a decrease in interlayer adhesive strength under a high temperature atmosphere, Since the shape of a laminated body can fully be hold | maintained, it is preferable.

  On the other hand, the weight (mass) average molecular weight of the polyalkyleneoxyglycol 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. If the 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). Etc.).

  Examples of the polar group of the modified polyester elastomer include an acid anhydride group, a carboxylic acid group, a carboxylic acid ester group, a carboxylic acid chloride group, a carboxylic acid amide group, a carboxylic acid group, a sulfonic acid group, and a sulfonic acid ester. Groups, sulfonated chloride groups, sulfonic acid amide groups, sulfonate groups, epoxy groups, amino groups, imide groups, or oxazoline groups, among which acid anhydride groups, carboxylic acid groups, or carboxylic acids An ester group is preferred.

  Examples of specific products of the modified polyester elastomer include “Primalloy AP series” (manufactured by Mitsubishi Chemical Corporation).

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

  In addition to the resin composition containing the polyester elastomer and the resin composition containing the modified polyester elastomer, the first layer contains, for example, 0.1% by mass or more of hydrocarbon resins, styrene resins, and polyester resins. It can contain 40 mass% or less. 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.

<Second layer>
The second layer of the laminate of the present invention is composed of a resin composition containing a polyester resin as a main component. After the second layer is laminated on the first layer to form a laminate, when the laminate is stretched in at least one direction to produce a heat-shrinkable film, the film has rigidity, fracture resistance, and low-temperature shrinkage. Natural shrinkage can be suppressed while imparting. A polyester resin suitable for the present invention is a polyester resin composition composed of a dicarboxylic acid component and a diol component, or a polylactic acid resin composition. Examples of the dicarboxylic acid component contained in the polyester resin composition composed of a dicarboxylic acid component and a diol component include terephthalic acid, isophthalic acid, 2-chloroterephthalic acid, 2,5-dichloroterephthalic acid, 2-methyl Terephthalic 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-diphenoxyethane dicarboxylic acid, 5-Na sulfoisophthalic acid, ethylene-bis-p-benzoic acid and other aromatic dicarboxylic acids, adipic acid, sebacic acid , Azelaic acid, dodecanedioic acid, 1,3-cyclohex Njikarubon acid component derived from aliphatic dicarboxylic acids or their ester derivatives, such as 1,4-cyclohexane dicarboxylic acid. These dicarboxylic acid components may be used alone or in combination of two or more. As the polyester resin, a polyester resin composed of terephthalic acid and ethylene glycol is preferably used.

  In the present invention, the polyester resin is more preferably a mixture composed of a dicarboxylic acid component and a diol component, and at least one of the dicarboxylic acid component and the diol component is composed of two or more components. In the present specification, when two or more kinds of components are included, the component having the largest mass (mol%) is defined as the first component, the amount smaller than the first component, and the largest component among the remaining components. The second component (hereinafter also referred to as a third component, a fourth component,...). By making the dicarboxylic acid component and the diol component into such a mixture system, the crystallinity of the resulting polyester resin can be lowered. Therefore, when used as the second layer of the laminate of the present invention, the crystal of the second layer This is preferable because the progress of the conversion can be suppressed.

  A preferred mixture of diol components includes, for example, an ethylene glycol component as the first component, 1,4-butanediol, neopentyl glycol, diethylene glycol, polytetramethylene glycol, and 1,4-cyclohexanedimethanol as the second component. A component derived from at least one selected from the group, preferably one using a 1,4-cyclohexanedimethanol component.

  The preferred mixture of dicarboxylic acid components is, for example, at least one selected from the group consisting of terephthalic acid component as the first component and isophthalic acid, 1,4-cyclohexanedicarboxylic acid, succinic acid and adipic acid as the second component. Examples include a component to be derived, preferably one using an isophthalic acid component.

  The total content of the dicarboxylic acid component and the diol component below the second component is the sum (200 mol%) of the total amount of the dicarboxylic acid component (100 mol%) and the total amount of the diol component (100 mol%). On the other hand, it is 10 mol% or more, preferably 20 mol% or more, and 50 mol% or less, preferably 40 mol% or less. If the content rate of the component below the said 2nd component is 10 mol% or more, the crystallinity degree of polyester obtained can be restrained low. On the other hand, if the content of the second component or less is 50 mol% or less, the advantages of the first component can be utilized.

  For example, when the dicarboxylic acid component is a terephthalic acid component, the first component of the diol component is an ethylene glycol component, and the second component is a 1,4-cyclohexanedimethanol component, The content of the methanol component is the sum of the total amount (100 mol%) of the terephthalic acid component as the dicarboxylic acid component and the total amount (100 mol%) of the ethylene glycol component and 1,4-cyclohexanedimethanol component (200 mol%). 10 mol% or more, preferably 15 mol% or more, more preferably 25 mol% or more, and 50 mol% or less, preferably 40 mol% or less, more preferably 35 mol% or less. . By using an ethylene glycol component and a 1,4-cyclohexanedimethanol component as the diol component within this range, the crystallinity of the resulting polyester is almost lost, and the fracture resistance can be improved.

  Furthermore, in the above example, when the dicarboxylic acid component is composed of a terephthalic acid component as the first component and an isophthalic acid component as the second component, the isophthalic acid component that is the dicarboxylic acid component and the 1,4-cyclohexanedimethanol component that is the diol component The total content of terephthalic acid component and isophthalic acid component (100 mol%) and the total amount (100 mol%) of ethylene glycol component and 1,4-cyclohexanedimethanol component (200 mol%) On the other hand, it is 10 mol% or more, preferably 15 mol% or more, more preferably 25 mol% or more, and 50 mol% or less, preferably 40% mol or less, more preferably 35 mol% or less.

  The refractive index (n1) of the polyester resin is 1.560 or more and 1.580 or less, preferably about 1.570.

  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. If intrinsic viscosity (IV) is 0.5 dl / g or more, it can suppress that a film strength characteristic and heat resistance fall. On the other hand, if the intrinsic viscosity is 1.5 dl / g or less, it is possible to prevent breakage associated with an increase in stretching tension.

  Examples of specific products of the polyester-based resin include “PETG copyester 6863”, “Embrace LV” (manufactured by Eastman Chemical Co.), “PETG SKYGREENS 2008” (manufactured by SK Chemical Co., Ltd.), and the like.

  The polyester resin used in the second layer of the laminate of the present invention has a carboxylic acid component and an alcohol component in one molecule in addition to the polyester resin derived from the dicarboxylic acid component and the diol component. Polyester resins obtained by polymerizing monomers can also be used. In particular, polylactic acid obtained by condensation polymerization of lactic acid can be suitably used because it imparts rigidity, low-temperature shrinkage, and low natural shrinkage.

  The polylactic acid resin suitably used as the polyester resin constituting the second layer is a homopolymer of D-lactic acid or L-lactic acid or a copolymer thereof, and a mixture thereof is also included. More specifically, poly (D-lactic acid) whose structural unit is D-lactic acid, poly (L-lactic acid) whose structural unit is L-lactic acid, and a copolymer of L-lactic acid and D-lactic acid. Poly (DL-lactic acid) or a mixture thereof.

  When the polylactic acid resin is a mixture of D-lactic acid and L-lactic acid, the mixing ratio of D-lactic acid and L-lactic acid is D-lactic acid / L-lactic acid = 99.8 / 0.2 to 75/25. Or D-lactic acid / L-lactic acid = 0.2 / 99.8 to 25/75, preferably D-lactic acid / L-lactic acid = 99.5 / 0.5 to 80/20 or It is more preferable that D-lactic acid / L-lactic acid = 0.5 / 99.5 to 20/80. Polylactic acid composed of D-lactic acid alone or L-lactic acid alone exhibits very high crystallinity, has a high melting point, and tends to be excellent in heat resistance and mechanical properties. However, when the laminate of the present invention is used as a heat-shrinkable film, it usually involves printing and a bag making process using a solvent, so that the crystallinity of the constituent material itself is improved in order to improve printability and solvent sealability. It is necessary to lower the value moderately. Moreover, when crystallinity is too high, orientation crystallization advances at the time of extending | stretching, and there exists a tendency for shrinkage | contraction characteristic to fall. From these, the mixing ratio of the polylactic acid resin used in the present invention is D-lactic acid / L-lactic acid = 99/1 to 85/15, or D-lactic acid / L-lactic acid = 1/99 to 15/85. Most preferably.

  In the present invention, the polylactic acid resin can be used by mixing copolymers of D-lactic acid and L-lactic acid having different copolymerization ratios. In that case, what is necessary is just to adjust so that the value which averaged the copolymerization ratio of D-lactic acid of a some lactic acid-type polymer and L-lactic acid may enter in the said range. Heat resistant when molded into a heat-shrinkable film by mixing two or more polylactic acid resins with different copolymer ratios of D-lactic acid and L-lactic acid, and adjusting the crystallinity. Balance between heat resistance and heat shrinkage characteristics.

  The polylactic acid resin used in the present invention may be a copolymer of lactic acid and α-hydroxycarboxylic acid, aliphatic diol, or aliphatic dicarboxylic acid. Here, the “α-hydroxycarboxylic acid” copolymerized with the lactic acid resin includes optical isomers of lactic acid (D-lactic acid for L-lactic acid, and L-lactic acid for D-lactic acid, respectively). Glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 2-hydroxy-n-butyric acid, 2-hydroxy-3,3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-methylbutyric acid, Bifunctional aliphatic hydroxy-carboxylic acids such as 2-hydroxycaprolactone acid and lactones such as caprolactone, butyl lactone and valerolactone. Examples of the aliphatic diol copolymerized with the lactic acid resin include ethylene glycol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. Examples of the aliphatic dicarboxylic acid to be copolymerized 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. The range is preferably in the range of / 10 to 10/90, more preferably 80/20 to 20/80, and still 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 polylactic acid resin can be prepared by a known polymerization method such as a condensation polymerization method or a ring-opening polymerization method. For example, in the case of a condensation polymerization method, a polylactic acid resin having an arbitrary composition can be obtained by directly dehydrating condensation polymerization of D-lactic acid, L-lactic acid, or a mixture thereof. Further, in the ring-opening polymerization method, a lactide which is a cyclic dimer of lactic acid is subjected to ring-opening polymerization in the presence of a predetermined catalyst while using a polymerization regulator or the like, if necessary. A lactic acid resin can be obtained. The lactide includes DL-lactide, which is a dimer of L-lactic acid. By mixing and polymerizing these as required, a polylactic acid resin having an arbitrary composition and crystallinity can be obtained. it can. Furthermore, a small amount of chain extender such as a diisocyanate compound, diepoxy compound, acid anhydride, acid chloride, etc. may be used for the purpose of increasing the molecular weight.

  The polylactic acid resin has a weight (mass) average molecular weight of 20,000 or more, preferably 40,000 or more, more preferably 60,000 or more, and 400,000 or less, preferably 350,000 or less, Preferably it is 300,000 or less. When the weight (mass) average molecular weight is 20,000 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 400,000 or less, the melt viscosity can be lowered, which is preferable from the viewpoint of production and productivity improvement.

  As a commercial item of the said polylactic acid-type resin, "NatureWorks" (made by NatureWorks LLC), "LACEA" (made by Mitsui Chemicals), etc. are mentioned, for example.

  The polyester resin contained in the second layer is 60% by mass or more, preferably 70% by mass or more, and more preferably 80% by mass or more with respect to the total resin amount of the second layer. A resin may be included. Examples of such resins include polyolefin resins, polystyrene resins, polycarbonate resins, and acrylic resins, among which polystyrene resins are preferable.

<Third layer>
The laminated body of this invention can have the 3rd layer comprised by the resin composition of a composition different from the resin composition which comprises a 2nd layer on the 1st layer on the opposite side to a 2nd layer. For example, if a third layer composed of polyester resin compositions having different compositions is provided on the first layer, different crystallinity can be imparted to the third layer and the second layer, and the crystallization rate of polyester in the laminate Can be adjusted.

  Examples of the resin composition used in the third layer include a styrene resin, a polycarbonate resin, a polyamide resin, a polyolefin resin, a poly (meth) acrylate resin, or a polyester resin constituting the second layer. Can include resin compositions containing different polyester resins as main components. Among these, when the third layer is composed of a resin composition containing a styrene-based resin as a main component, it is suitably used because sufficient delamination strength can be imparted to the laminate.

  As the styrene resin constituting the third layer, block copolymerization of a styrene hydrocarbon and a conjugated diene hydrocarbon is preferably used. Examples of the styrenic hydrocarbon include polystyrene, poly (p-, m- or o-methylstyrene), poly (2,4-, 2,5-, 3,4- or 3,5-dimethylstyrene), Polyalkylstyrenes such as poly (pt-butylstyrene); poly (o-, m- or p-chlorostyrene), poly (o-, m- or p-bromostyrene), poly (o-, m- Or p-fluorostyrene), poly (halogenated styrene) such as poly (o-methyl-p-fluorostyrene); polyhalogenated substituted alkylstyrene such as poly (o-, m- or p-chloromethylstyrene); poly ( p-, m-, or o-methoxystyrene), poly (o-, m-, or p-ethoxystyrene) and other polyalkoxystyrenes; poly (o-, m-, or p-carboxymethylstyrene), etc. Li carboxyalkyl styrene; poly (p- vinylbenzyl ether) such as poly alkyl ether styrene, poly (p- trimethylsilylstyrene) polyalkyl silyl styrene such as; more polyvinyl benzyl dimethoxy phosphite, and the like. The styrenic hydrocarbon block may contain a homopolymer, a copolymer and / or a copolymerizable monomer other than the styrenic hydrocarbon in the block.

  Examples of the conjugated diene hydrocarbon include butadiene, isoprene, 2-methyl-1,3 butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3 hexadiene, and the like. The conjugated diene hydrocarbon block may contain a copolymerizable monomer other than these homopolymers, copolymers and / or conjugated diene hydrocarbons in the block.

  As one of the block copolymers of styrene hydrocarbons and conjugated diene hydrocarbons preferably used in the third layer, styrene hydrocarbon is styrene and conjugated diene hydrocarbon is butadiene. A butadiene block copolymer (SBS) may be mentioned. SBS preferably has a styrene / butadiene mass% ratio of about (95-60) / (5-40), more preferably (93-60) / (7-40), (90- More preferably, it is about 60) / (10-40). Further, the melt flow rate (MFR) measured value of SBS (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 It is desirable that it is 10 g / 10 min or less, more preferably 8 g / 10 min or less.

  In the present invention, a styrene-isoprene-butadiene block copolymer (SIBS) is also preferably used as a block copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon. In SIBS, the mass% ratio of styrene / isoprene / butadiene is preferably (60-90) / (5-40) / (5-30), (60-85) / (10-30) / ( 5 to 25) is more preferable, and (60 to 80) / (10 to 25) / (5 to 20) is more preferable. Further, the melt flow rate (MFR) measurement value (measurement conditions: temperature 200 ° C., load 49 N) of SIBS is 2 g / 10 min or more, preferably 3 g / 10 min or more, and 15 g / 10 min or less, preferably It is desirable that it is 10 g / 10 min or less, more preferably 8 g / 10 min or less. If the butadiene content is high and the isoprene content is low, the butadiene heated inside the extruder or the like may cause a cross-linking reaction to increase the gel-like material. On the other hand, when the butadiene content is low and the isoprene content is high, the cross-linking reaction of butadiene may be suppressed, and the gel-like product may be suppressed.

  The styrenic resin is not limited to a simple substance, and may be a mixture of two or more. For example, when the styrenic resin is a mixture of SBS and SIBS, the mass% ratio of SBS / SIBS is preferably about (90 to 10) / (10 to 90), and (80 to 20) / ( More preferably, it is about 20-80), more preferably about (70-30) / (30-70).

  The content of the styrenic resin contained in the third layer is 50% by mass or more of the total amount of the resin composition constituting the third layer, preferably 65% by mass or more, and 80% by mass or more. Is more preferable. However, when GPPS is contained, TPS (peak temperature of loss elastic modulus E ″) of GPPS is as high as about 100 ° C., so the content of GPPS to be mixed is 20 mass of the total amount of the resin constituting the third layer. % Or less, preferably 15% by mass or less, more preferably 10% by mass or less.

  If the styrenic resin contained in the third layer is contained in an amount of 50% by mass or more of the total amount of the resin composition constituting the third layer as described above, other resins can be mixed. Examples of such miscible resins include polyester resins, resins containing polyester elastomers or modified polyester elastomers, polyolefin resins, acrylic resins, polycarbonate resins, and the like. Among them, a polyester resin, or a resin containing a polyester elastomer or a modified polyester elastomer is preferable, and is 40% by mass or less, preferably 35% by mass or less, more preferably 30% by mass, based on the total amount of the resin composition constituting the third layer. It is desirable to be included at the following content.

  When the styrene resin contained in the third layer is a block copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon, the refractive index (n2) measured in accordance with JIS K7142 of the block copolymer Is within the range of ± 0.02, preferably ± 0.015 of the refractive index (n1) of the polyester-based resin composition contained in the second layer. Thus, the laminate of the present invention was formed into a heat-shrinkable film by adjusting the difference between the refractive index (n2) of the third layer and the refractive index (n1) of the second layer within a predetermined range. In this case, a film having good transparency can be obtained even when a cut piece of the film generated in the film production process is kneaded into a third layer to be described later.

  The block copolymer of the styrene hydrocarbon and the conjugated diene hydrocarbon has a refractive index (n2) substantially equal to a desired value by appropriately adjusting the composition ratio of the styrene hydrocarbon and the conjugated diene hydrocarbon. Can be adjusted. Therefore, the composition ratio of the styrene hydrocarbon and the conjugated diene hydrocarbon of the block copolymer used in the third layer is adjusted corresponding to the refractive index (n1) of the polyester resin used in the second layer. Thus, a refractive index (n2) within the range of n1 ± 0.02 is obtained. This predetermined refractive index may be adjusted with a block copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon alone or may be adjusted by mixing two or more resins.

In the present invention, the storage elastic modulus (E ′) at 0 ° C. of the styrenic resin contained in the third layer is preferably 1.00 × 10 ⁹ Pa or more, and 1.50 × 10 ⁹ Pa or more. More preferably. The storage elastic modulus (E ′) at 0 ° C. represents the rigidity of the film, that is, the strength of the film when the styrenic resin composition is formed into a film having a predetermined thickness. By having a storage elastic modulus (E ′) of 1.00 × 10 ⁹ Pa or more, when the laminate of the present invention is formed into a film, a film having rigidity in addition to transparency can be obtained. This storage elastic modulus (E ′) is a block copolymer of the above-mentioned styrenic hydrocarbon and conjugated diene hydrocarbon, a mixture of two or more of these copolymers, or a range that does not impair transparency. It can be obtained by mixing with other resins.

  When using a mixed system of a block copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon or a mixed system of the copolymer and another resin as the main component of the third layer, it bears fracture resistance. Good results can be obtained by appropriately selecting a copolymer or resin to be cured and a copolymer or resin to impart rigidity. That is, by combining a block copolymer of styrene hydrocarbon-conjugated diene hydrocarbon having high fracture resistance and a block copolymer of styrene hydrocarbon-conjugated diene hydrocarbon having high rigidity, Alternatively, by mixing a block copolymer of styrenic hydrocarbon-conjugated diene hydrocarbon having high fracture resistance and another kind of resin composition having high rigidity, the styrenic hydrocarbon-conjugated The total composition of the diene hydrocarbons or a mixture of these with other types of resins can be adjusted to satisfy the desired refractive index (n2) and the storage elastic modulus (E ′) at 0 ° C.

Preference is given to pure block SBS and random block SBS as block copolymers of styrenic hydrocarbon-conjugated diene hydrocarbon that can impart rupture resistance. Among them, the storage elastic modulus (E ′) at 0 ° C. is 1.00 × 10 ⁸ Pa or more and 1.00 × 10 ⁹ Pa or less, and at least one of the peak temperatures of the loss elastic modulus (E ″) is −20. Those having viscoelastic properties at or below 0 ° C. are particularly preferred.If the storage elastic modulus at 0 ° C. is 1.0 × 10 ⁸ Pa or more, the laminate is formed into a film by increasing the blend amount of the resin responsible for rigidity. In such a case, it is possible to impart stiffness to the film. On the other hand, at the peak temperature of the loss modulus (E ″), the temperature on the low temperature side mainly shows fracture resistance. Although the properties vary depending on the stretching conditions, when the peak temperature of the loss modulus (E ″) does not exist below −20 ° C. before stretching, sufficient breakability can be obtained when the laminate is formed into a film. It may be difficult to apply to the film.

Further, as a resin capable of imparting rigidity, a copolymer composed of a styrene hydrocarbon having a storage elastic modulus (E ′) at 0 ° C. of 2.00 × 10 ⁹ Pa or more, for example, a styrene resin having a controlled block structure Examples thereof include block copolymers of hydrocarbons and conjugated diene hydrocarbons, polystyrene, styrene hydrocarbons and aliphatic unsaturated carboxylic acid ester copolymers.

The styrene hydrocarbon-conjugated diene hydrocarbon block copolymer having a controlled block structure has a storage elastic modulus (E ′) at 0 ° C. of 2.00 × 10 ⁹ as a characteristic of the styrene-butadiene block copolymer. SBS that is Pa or higher is exemplified. The composition ratio of styrene-butadiene of SBS satisfying this is preferably adjusted to about styrene / butadiene = (95-80) / (5-20).

  The structure of the block copolymer and the structure of each block part are preferably a random block and a tapered block. More preferably, in order to control the shrinkage characteristic, the peak temperature of the loss modulus (E ″) is 40 ° C. or more, and more preferably, the peak of the clear loss modulus (E ″) is 40 ° C. or less. There is no temperature. When the peak temperature of the loss elastic modulus (E ″) 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. The peak temperature of the loss modulus (E ″) is preferably in the range of 40 ° C. or more and 90 ° C. or less. This peak temperature is a factor that mainly affects the shrinkage rate. If this temperature is in the range of 40 ° C. or more and 90 ° C. or less, the natural shrinkage and the low temperature shrinkage rate are not extremely lowered.

  A polymerization method of a styrene-based hydrocarbon-conjugated diene-based hydrocarbon copolymer that satisfies the above viscoelastic properties is shown below. Usually, 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. This preferentially polymerizes butadiene having a higher polymerization activity, and finally a block composed of a single monomer of styrene is generated. For example, when styrene is homopolymerized first, and after the polymerization is completed, a mixture of styrene monomer and butadiene monomer is added and polymerization is continued, the styrene / butadiene monomer ratio gradually changes between the styrene block and the butadiene block. A styrene-butadiene block copolymer having a copolymer site is obtained. By providing such a site, a polymer having the above viscoelastic properties can be obtained. 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. That is, in a block structure such as SBS of a random block in which a pure block and a butadiene block are clearly present, Tg due to the butadiene block is mainly present at 0 ° C. or less, and therefore, storage modulus at 0 ° C. ( It becomes difficult for E ′) to be not less than a predetermined value. Regarding the molecular weight, the melt flow rate (MFR) measurement value (measurement conditions: temperature 200 ° C., load 49 N) is adjusted in the range of 2 g / 10 min to 15 g / 10 min. The mixing amount of the styrene-butadiene block copolymer imparting this rigidity is appropriately adjusted according to the properties of the laminate, and is preferably 20% by mass or more and 80% by mass or less, preferably 20% by mass or less of the total amount of the resin composition constituting the third layer. Is preferably adjusted in the range of 40% by mass to 70% by mass. If the mixing amount of styrene-butadiene block copolymer is 80% by mass or less of the total amount of the resin composition, the rigidity of the film can be greatly improved when the laminate is formed into a film, and the decrease in fracture resistance is suppressed. It is done. On the other hand, if the mixing amount of the styrene-butadiene block copolymer is 20% by mass or more of the total amount of the resin composition, sufficient rigidity can be imparted to the film.

  The molecular weight of the styrenic resin contained in the third layer has a weight (mass) average molecular weight (Mw) of 100,000 or more, preferably 150,000 or more, and 500,000 or less, preferably 400,000 or less. More preferably, it is 300,000 or less. If the weight (mass) average molecular weight (Mw) of a styrene resin is 100,000 or more, it is preferable without a defect which causes deterioration of a film. Further, if the weight (mass) average molecular weight (Mw) of the styrene-based resin is 500,000 or less, it is not necessary to adjust the flow characteristics and there is no defect such as a decrease in extrudability, which is preferable.

  When a copolymer of a styrene hydrocarbon and an aliphatic unsaturated carboxylic acid ester is used as the styrene resin, the aliphatic unsaturated carboxylic acid ester copolymerized with the styrene hydrocarbon includes methyl (meth) acrylate, butyl (Meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate may be mentioned. Preferably, it is a copolymer of styrene and butyl (meth) acrylate, more preferably styrene is in the range of 70% by mass to 90% by mass, and Tg (peak temperature of loss elastic modulus E ″). One having a melt flow rate (MFR) measurement value (measurement conditions: temperature 200 ° C., load 49 N) of 2 g / 10 min or more and 15 g / 10 min or less is used. And acrylate and / or methacrylate.

  Content in the 3rd layer of the copolymer of a styrene-type hydrocarbon and aliphatic unsaturated carboxylic acid ester is suitably determined according to the composition ratio. Typically, it is adjusted in the range of 20% by mass or more and 70% by mass or less with respect to the total amount of the resin composition constituting the third layer. If the content of the copolymer is mixed at 70% by mass or less, when the laminate of the present invention is formed into a film, the rigidity of the film can be greatly improved and good fracture resistance can be maintained. Moreover, if it mixes by 20 mass% or more, sufficient rigidity can be provided to a film.

  In addition to the components described above, the laminate of the present invention is a plasticizer in each layer for the purpose of improving and adjusting the molding processability, productivity, and various physical properties of the film after molding within a range that does not significantly impair the effects of the present invention. And / or the tackifying resin is 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass or more, and 10% by mass or less, preferably 8% by mass with respect to the total amount of the resin constituting each layer. Hereinafter, it can be contained in a range of 5% by mass or less. When the content of the plasticizer and / or tackifying resin is 10% by mass or less with respect to the total amount of the resin, the decrease in melt viscosity and the decrease in heat-resistant fusing property are small, and natural shrinkage hardly occurs. In addition to the plasticizer and tackifier resin, the laminate of the present invention may have various additives depending on the purpose, for example, an ultraviolet absorber, a light stabilizer, an antioxidant, a stabilizer, a colorant, and an antistatic agent. A lubricant, an inorganic filler, and the like can be appropriately added according to each application.

<Layer structure>
The layer structure of the present invention is not particularly limited as long as it has a structure of two or more layers having at least a first layer and a second layer. For example, the layer structure of the first layer / second layer, A layer structure of two layers / first layer / second layer, second layer / first layer / second layer / first layer / second layer can be adopted. Preferably, it is a layer structure having a third layer composed of a resin composition having a composition different from that of the resin composition constituting the second layer on the first layer opposite to the second layer, more preferably the third layer. The layer is a layer composed of a resin composition containing a polystyrene-based resin as a main component.

  In the present invention, a preferred laminated structure is a five-layer structure comprising second layer / first layer / third layer / first layer / second layer. By adopting this layer structure, when the laminate of the present invention is formed into a heat-shrinkable film, the object film has excellent rigidity, shrinkage finish, rupture resistance, and delamination is suppressed. Further, a heat-shrinkable film suitable for applications such as shrink-bound packaging and shrinkage labels can be obtained with good productivity and economy.

  Next, a laminate having a five-layer structure of second layer / first layer / third layer / first layer / second layer, which is one of the preferred embodiments of the present invention, will be described. However, as long as there is no particular problem, this description is applicable to other layer configurations.

  In the laminate of the present invention, the thickness ratio between the second layer and the third layer, when the second layer is 1, the third layer is 2 or more, preferably 3 or more, more preferably 4 or more, And it is 12 or less, preferably 10 or less, more preferably 8 or less. The thickness of the first layer is 5% or more of the thickness of the second layer, preferably 10% or more, 150% or less, preferably 100% or less, more preferably 80% or less. . If the thickness of the first layer is 5% or more of the thickness of the second layer, a good adhesive effect is obtained, and if the thickness is 150% or less, that is, 1.5 times or less the thickness of the second layer. Transparency is not significantly reduced.

  Although the total thickness of the laminate of the present invention is not particularly limited, the thickness before forming into a heat-shrinkable film (thickness in an unstretched state) is 500 μm or less, preferably 400 μm or less, preferably 300 μm or less. More preferably, the lower limit is preferably 10 μm from the viewpoint of handling.

  In the laminate of the present invention, the peel strength between the first layer and the second layer after a predetermined treatment has a predetermined value. That is, the laminate was stretched in at least one direction to produce a heat-shrinkable film, and a test piece having a size of 150 mm in the main shrinkage direction and 15 mm in the direction perpendicular to the main shrinkage direction was collected from the heat-shrinkable film. Thereafter, a part of the second layer is peeled off from the film end surface in the main shrinkage direction of the test piece to form a peeled portion on the second layer and a peeled portion on the first layer, respectively. The peel strength and the peeled portion of the first layer are sandwiched by a chuck of a tensile tester, and the delamination strength is 1 N / 15 mm width or more when a 180 degree peel test is performed at a test speed of 100 mm / min with respect to the main shrinkage direction. Preferably, it is 2N / 15mm width or more, more preferably 4N / 15mm width or more, 20N / 15mm width or less, preferably 18N / 15mm width or less, more preferably 15N / 15m. It is desirable that it is less than m width. Since the laminate of the present invention has a delamination strength of 1 N / 15 mm or more when formed into a heat-shrinkable film, troubles such as peeling of the seal portion during use do not occur.

<Difference width in the overlapped part>
Next, the deviation width of the overlapping portion in the laminate of the present invention will be described with reference to the drawings. In addition, what has the same function attaches | subjects the same code | symbol, and shall abbreviate | omit description.
In FIG. 1 to FIG. 5, reference numeral 100 represents a test piece, which represents a test piece obtained by stretching the laminate of the present invention in at least one direction to produce a heat-shrinkable film and cutting it to a predetermined size. Reference numeral 2 is the second layer, reference numeral 4 is the first layer, reference numeral 6 is the third layer, reference numeral 8 is the overlapping portion, reference numeral 8w is the overlapping width of the overlapping portion, reference numeral 10 is the end surface of the second layer 2, Reference numeral 12 denotes an end face of the first layer 4, reference numeral 14 denotes an end face of the third layer 6, reference numeral 16 denotes a seal portion, reference numeral 18 denotes a deviation portion, reference numeral 18w denotes a deviation width, reference numeral A denotes one end side, and reference numeral B denotes the other end side. Means each. Note that the portion on one end side A and the portion on the other end side B are overlapped to form an overlapped portion.

  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 second layer (2), the first layer (4), and the third layer (6) from above. 3 and 4 are the superposition of films laminated in the order of the second layer (2), the first layer (4), the third layer (6), the first layer (4), and the second layer (2) from the top. It is sectional drawing in the vicinity of a part (8). Moreover, (a) is drawing which shows the state before heat processing among each drawing, (b) is the 2nd layer (2) or 2nd layer (2) and 1st of a film in the superposition part (8) after heat processing. It is drawing which shows the state which produced the gap between a layer (4) and a 3rd layer (6). FIG. 5A shows a heat-shrinkable film produced by stretching the laminate of the present invention in at least one direction. The heat-shrinkable film is 235 mm in the main shrinkage direction and 500 mm in the direction perpendicular to the main shrinkage direction. The test piece (100) which cut out the rectangular film of a magnitude | size is shown, FIG.5 (b) is the surface of the 2nd layer (2) of the one end side A of the test piece (100) in the direction orthogonal to the main contraction direction. And 10 mm on the laminated film solvent-sealed so that the surface of the third layer (6) or the surface of the second layer (2) on the other end side B in the same direction is parallel to the direction perpendicular to the main shrinkage direction. It is drawing explaining the state which formed the overlapping part (8) of width.

  As shown in FIG. 5, the laminate of the present invention is formed from the produced film roll in a direction perpendicular to the take-off direction (MD) (TD), that is, 235 mm in the main shrinkage direction, and in the take-up direction (MD), that is, the main shrinkage direction. A film is cut out with a size of 500 mm in a direction orthogonal to the direction of the test piece (100). Next, the surface of the second layer (2) on one end side A in the direction orthogonal to the main contraction direction of the test piece (100) and the surface of the third layer (6) on the other end side B in the same direction or the second layer A solvent seal is performed so that the surface of (2) is parallel to form a 10 mm wide overlap portion (8) on the test piece, and heat treatment is performed at 90 ° C. for 5 seconds. In the present invention, “heat treatment at 90 ° C. for 5 seconds” means a state in which the heat treatment is performed for 5 seconds in a 90 ° C. steam tunnel.

  When the sample is returned to room temperature after being heat-treated at 90 ° C., the test piece is an end face in the direction (MD) perpendicular to the main shrinkage direction of the second layer (2) which is solvent-sealed by the overlapping portion (8). (10) or the end face (10, 12) of the second layer (2) and the first layer (4), and the end face (12, 14) or the first face of the MD of the first layer (4) and the third layer (6). The deviation width (18w) of the deviation (18) between the end faces (14) of the three layers (6) is within 5% with respect to the overlapping width (8w) of the overlapping portion (8).

  FIG. 1 is an example of a three-layer three-layer film having a first layer (4) between a second layer (2) and a third layer (6). When the test piece (100) obtained from the laminate of the present invention is heat-treated at 90 ° C. and then returned to room temperature, the take-off direction of the second layer (2) that is solvent-sealed by the overlapping portion (8) ( There is a gap (18) between the end face (10) of MD) and the end faces (12, 14) in the direction (MD) perpendicular to the main shrinkage direction of the first layer (4) and the third layer (6). The resulting state is shown. In this case, the deviation width (18w) is within 5% with respect to the overlapping width (8w) of the overlapping portion (8).

  FIG. 2 shows an example of three types and three layers, similar to FIG. 1, and the second layer (2) and the first layer that are solvent-sealed by the overlapping portion (8) when the temperature is returned to room temperature after the heat treatment. Between the end face (10, 12) in the direction (MD) perpendicular to the main shrinkage direction of the layer (4) and the end face (14) in the direction (MD) perpendicular to the main shrinkage direction of the third layer (6). The state which the gap | deviation part (18) produced has been shown. Even in this case, the deviation width (18w) 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 second layer (2), the first layer (4), the third layer (6), the first layer (4), and the second layer (2). 3 shows an end face (10) in a direction perpendicular to the main shrinkage direction of the second layer (2) sealed by the overlapping portion (8) when the temperature is returned to room temperature after the heat treatment, and the first layer. (4), the third layer (6), the first layer (4), and the third layer (6) are shifted from the end surfaces (12, 14, 12, 10) in the direction orthogonal to the main shrinkage direction ( 18) has occurred. FIG. 4 shows an end face in a direction perpendicular to the main shrinkage direction of the second layer (2) and the first layer (4) sealed by the overlapping portion (8) when the temperature is returned to room temperature after the heat treatment. 10, 12) and the end face (14, 12, 10) in the direction orthogonal to the main contraction direction of the third layer (6), the first layer (4), and the second layer (2) 18) has occurred. Even in these cases, the deviation width (18w) 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 film comprising the laminate of the present invention has a heat treatment between the second layer (outer layer) and the first layer (adhesive layer) or between the first layer (adhesive layer) and the third layer (inner layer). ), And an excellent appearance can be obtained.

  In the laminated body of the present invention, the ease of peeling between layers after heat treatment can be represented by a gap generated between the outer layer and the adhesive layer after sealing or between the adhesive layer and the inner layer. That is, the laminate of the present invention is stretched in at least one direction to produce a heat-shrinkable film, and is tested with a size of 235 mm in the main shrinkage direction and 500 mm in the direction orthogonal to the main shrinkage direction from this heat-shrinkable film. After collecting the piece, the surface of the second layer on one end side in the direction orthogonal to the main shrinkage direction of the test piece is parallel to the surface of the third layer or the second layer on the other end side in the same direction. In this way, a 10 mm wide overlapping portion is formed on the test piece, and after sealing with a solvent, a 165 mm cylindrical film is cut out in a direction perpendicular to the main shrinkage direction and shrunk in a steam tunnel at 90 ° C. for 5 seconds. When the temperature is returned to room temperature, the gap width between the end face of the second layer and the end face of the first layer and the third layer in the direction orthogonal to the main shrinkage direction sealed in the overlapping portion, or the main shrinkage In the direction perpendicular to the direction It is important that the deviation width between the end faces of the layer and the first layer and the end face of the third layer is within 5% of the overlapping width of the overlapping portion, preferably within 3%, more preferably Is 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.

  Here, "the surface of the second layer on the other end side in the same direction as the surface of the second layer on the one end side ... (omission) ... solvent-sealed" means that the laminate of the present invention For example, the layer structure is assumed to be a laminate of the second layer (2) on both sides of the first layer (4) as shown in FIG. 3 or FIG. The surface of 2) and the surface of the second layer (2) on the other end side are solvent-sealed.

  The overlapping portion is parallel to the surface of the second layer at one end in the direction orthogonal to the main contraction direction of the test piece and the surface of the third layer or the second layer at the other end in the same direction. Is a portion overlapped with a width of 10 mm on the test piece. As a solvent used for solvent-sealing the surface of the second layer on one end side and the surface of the third layer or the second layer on the other end side, pentane, n-hexane, diethyl ether, heptane, octane, Cyclohexane, isopropyl acetate, n-butyl acetate, n-propyl acetate, carbon tetrachloride, xylene, ethyl acetate, toluene, benzene, methyl methyl ketone, methyl acetate, methylene chloride, tetrahydrofuran, dioxolane, acetone, isopropanol, ethanol, Mention may be made of methanol or a mixed solvent comprising at least two of these solvents. The solvent 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.

  Further, the laminate of the present invention is stretched in at least one direction to produce a heat-shrinkable film, and is tested at a size of 235 mm in the main shrinkage direction and 500 mm in the direction orthogonal to the main shrinkage direction from this heat-shrinkable film. After collecting the piece, the surface of the second layer on one end side in the direction orthogonal to the main shrinkage direction of the test piece is parallel to the surface of the third layer or the second layer on the other end side in the same direction. After forming a 10 mm wide overlapping portion on the test piece and solvent-sealing, cut out a 30 mm cylindrical film in the direction orthogonal to the main shrinkage direction (the circumference of the cylindrical film is about 225 mm), then this cylindrical shape When immersed in 95 ° C. warm water for 30 seconds with both ends of the film being sandwiched, the end face of the second layer in the direction orthogonal to the main shrinkage direction sealed in the overlapping portion and the first Layer and third layer The deviation width between the end faces, or the deviation width between the end faces of the second layer and the first layer in the direction orthogonal to the main contraction direction and the end face of the third layer is 5 of the overlapping width of the overlapping portion. %, Preferably within 3%, more preferably within 2%.

  The laminate of the present invention can maintain excellent delamination strength even when the treatment is performed under conditions more severe than those described above. That is, the laminate of the present invention is stretched in at least one direction to produce a heat-shrinkable film, and the obtained heat-shrinkable film is slit in the main shrinkage direction with a width of 235 mm to produce a test piece. Next, the surface of the second layer on one end side in the direction orthogonal to the main contraction direction of the test piece and the surface of the third layer or the second layer on the other end side in the same direction are parallel to each other on the test piece. A 10 mm wide overlapping portion is formed, and bonded with a solvent in which, for example, THF and cyclohexane are mixed in half by volume to produce a cylindrical film. Next, a 30 mm cylindrical film is cut out in a direction perpendicular to the main shrinkage direction (the circumference of the cylindrical film is about 225 mm). By cutting the circumferential portion on the opposite side of the solvent-bonded portion of the cylindrical film, an MD30 mm × TD225 mm strip-shaped film having a solvent-bonded portion at the center is produced. Thereafter, the strip-shaped film is sandwiched between two metal frames fixed at a width of 130 mm at both ends of the strip-shaped film in a state where the strip-shaped film is slackened in a main contraction direction of 143 mm. The film is immersed in a warm water bath for 30 seconds, and then immersed in cold water at 23 ° C. for 30 seconds. Then, the contracted film is removed from the metal frame, and the state of the solvent-bonded portion of the film is compared.

<Application>
The laminated body 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 body of this invention is used as a heat-shrinkable film is demonstrated.

[Heat shrinkable film]
The heat-shrinkable film of the present invention can be obtained by stretching the laminate of the present invention in at least one direction. The heat-shrinkable film of the present invention can impart rigidity and rupture resistance to the film by using a resin composition containing a polyester-based resin as a main component in the second layer, and enables low-temperature shrinkage. Shrinkage can be suppressed. However, uniform shrinkage cannot be obtained only with a polyester resin, and there is a problem of shrinkage finish failure such as shrinkage unevenness and a defect in appearance due to shrinkage in the main shrinkage direction and orthogonal direction in label applications.

  Therefore, the heat-shrinkable film is a resin composition mainly composed of a resin having a composition different from the resin composition comprising the second layer and the resin composition constituting the second layer, the resin composition containing a polyester resin as a main component. The above problem can be solved by laminating the third layer composed of However, the heat-shrinkable film composed of the second layer and the third layer is formed by laminating layers composed of resin compositions having different compositions. There is a problem that delamination occurs, the second layer and the third layer are peeled off due to friction between films during transportation of the product after the label is attached, or scratching by a human nail or the like. Therefore, the heat-shrinkable film of the present invention is a resin composition containing a polyester-based elastomer or a modified polyester-based elastomer between the second layer and the third layer, or a resin composition thereof, in order to eliminate the above-mentioned drawbacks. The interlaminar peel strength is improved by interposing a first layer composed mainly of a mixed resin composition.

  Although the total thickness of the heat-shrinkable film of the present invention is not particularly limited, it is preferably thinner from the viewpoint of suppressing raw material costs as much as possible. Specifically, the thickness after stretching is preferably 70 μm or less, and preferably 60 μm or less. Is more preferably 55 μm or less, and most preferably 50 μm or less.

The heat-shrinkable film of the present invention has a heat shrinkage rate in the main shrinkage direction of 10% or more and less than 30%, preferably 10% or more and 28% or less, more preferably 12% or more when immersed in warm water at 70 ° C. for 10 seconds. The range is 25% or less. The heat-shrinkable film of the present invention has a heat shrinkage rate in the main shrinkage direction of 20% or more, preferably 25% or more, more preferably 30% or more when immersed in warm water at 80 ° C. for 10 seconds, and 80% or less, preferably 75% or less, more preferably 70% or less.
In the present specification, the “main contraction direction” means a direction in which the stretching direction is larger between the longitudinal direction and the transverse direction, and is a direction corresponding to the outer peripheral direction when the bottle is attached to a bottle, for example. The “direction orthogonal to the main contraction direction” means a direction in which the stretching direction is small in the longitudinal direction and the transverse direction.

  If the heat shrinkage rate in the main shrinkage direction when immersed in warm water at 70 ° C. and 80 ° C. for 10 seconds is within the above range, the heat shrinkable film is temporarily fixed to, for example, a container in a low temperature region near 70 ° C. In addition, the shrinkage of the container rapidly starts in a high temperature range exceeding 70 ° C and near 80 ° C. In addition, no abnormalities such as wrinkles and avatars occur on the thin neck and top surface, and uniform shrinkage is obtained, resulting in a beautiful shrinkage finish.

  If the heat shrinkage rate in the main shrinkage direction near 70 ° C. is less than 10%, the heat shrinkage force is small. For example, when a heat shrinkable film is used as the container label, it cannot be temporarily fixed to the container. When the temperature is high, the film may be displaced in the direction of the top surface. On the other hand, if the thermal contraction rate in the main contraction direction is higher than 30% at around 70 ° C., the thermal contraction may occur suddenly in a low temperature region, so that the thermal contraction may not be performed at a predetermined position. On the other hand, if the heat shrinkage rate in the main shrinkage direction near 80 ° C. is less than 20%, the heat shrinkage rate in the main shrinkage direction near 80 ° C. It is desirable that it is 20% or more, preferably 25% or more, more preferably 30% or more.

  When the heat-shrinkable film of the present invention is used as a PET container label, the heat shrinkage rate in the direction perpendicular to the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds is preferably 10% or less, It is more preferably 5% or less, and particularly preferably 3% or less. Further, the thermal shrinkage in the orthogonal direction when immersed in warm water at 70 ° C. for 10 seconds is preferably 10% or less, more preferably 5% or less, and particularly preferably 3% or less. When the shrinkage rate in the orthogonal direction exceeds 10%, the shrinkage in the vertical direction becomes remarkable after shrinkage in label applications, which may cause a dimensional deviation or an appearance defect.

  The transparency of the heat-shrinkable film of the present invention is evaluated by a haze value measured according to JIS K7105. The haze value is preferably 10% or less, more preferably 8% or less, and 5%. The following are particularly preferred: If the haze value is 10% or less, good transparency can be obtained, and beautiful printing or the like becomes possible.

  The heat-shrinkable film of the present invention is measured in accordance with JIS K7105 even when the heat-shrinkable film of the present invention recycled to the second layer and the third layer, preferably the third layer is added again. The haze value is 10% or less, preferably 8% or less, more preferably 5% or less. If the haze value after re-adding the recycled product is 10% or less, good transparency in the recycled film can be maintained.

  When the recycled product of the heat-shrinkable film of the present invention is regenerated and added to the third layer, the content of the resin composition containing the polyester resin contained in the third layer is that of the resin composition constituting the third layer. It is desirable that it is 40% by mass or less, preferably 35% by mass or less, more preferably 30% by mass or less, based on the total amount. Further, the content of the resin composition containing the polyester elastomer or the modified polyester elastomer contained in the third layer or the mixed resin composition thereof is 10 mass relative to the total amount of the resin composition constituting the third layer. % Or less, preferably 8% by mass or less, more preferably 6% by mass or less. If the content of the resin composition containing the polyester resin, the resin composition containing the polyester elastomer or the modified polyester elastomer or the mixed resin composition thereof is 10% by mass or less, the polystyrene constituting the third layer This is preferable because significant deterioration in transparency due to the difference in refractive index difference from the resin can be suppressed.

(Manufacturing method of laminate and heat-shrinkable film)
The laminate of the present invention includes a resin composition containing a polyester-based elastomer, a resin composition containing a modified polyester-based elastomer, or a first layer composed mainly of these mixed resin compositions, and a polyester-based resin. It is obtained by laminating the second layer composed mainly of the same or sequentially. Further, when a third layer composed mainly of a resin composition having a composition different from that of the second layer is provided on the first layer opposite to the second layer, the first layer, the second layer, and the third layer It is obtained by laminating layers simultaneously or sequentially. Preferably, the laminate of the present invention is co-extruded by an existing method such as a T-die method or a tubular method using an extruder equipped with a T-die, whereby the first layer and the second layer, or the first layer, In this method, the second layer and the third layer are formed simultaneously. In addition, the laminate of the present invention can also be sequentially produced by separately forming the resin composition constituting each layer into a sheet and then using a press method or a roll nip method.

  The heat-shrinkable film of the present invention can be obtained by stretching the laminate of the present invention in at least one direction at a predetermined temperature. Specifically, after cooling with a cooling roll, air, water, etc., reheat by an appropriate method such as hot air, hot water, infrared rays, etc., by roll stretching method, tenter stretching method, tubular stretching method, long interval stretching method, etc. These are uniaxially or biaxially stretched simultaneously or sequentially. In biaxial stretching, stretching in the MD and TD directions may be performed at the same time, but sequential biaxial stretching in which one of them is performed first is effective, and the order of either MD or TD may be first. The stretching temperature needs to be changed depending on the softening temperature of the resin constituting the film and the use required for the heat-shrinkable laminated film, but is generally 60 ° C., preferably 70 ° C. or more, and 130 ° C. or less, preferably 120 It is controlled in the range of ℃ or less. The draw ratio in the main shrink direction (TD) is 2 times or more, preferably 3 times or more, more preferably 4 times or more, and 7 times depending on the film constituents, stretching means, stretching temperature, and target product form. Hereinafter, it is suitably determined within a range of preferably 6 times or less. Whether to use uniaxial stretching or biaxial stretching is determined by the application of the target product.

  Even in the case of an application that requires shrinkage characteristics in almost one direction, such as a PET container label, it is effective to stretch the film in a range that does not impair the shrinkage characteristics in the vertical direction. The stretching temperature depends on components other than PET, but typically ranges from 60 ° C. to 90 ° C. Furthermore, with respect to the draw ratio, as the size is increased, the fracture resistance is improved, but the heat shrinkage rate is increased accordingly, and it is difficult to obtain a good shrinkage finish. It is particularly preferred that

  Moreover, the heat-shrinkable film of the present invention can be imparted and held shrinkage by quickly cooling the film within a time when the molecular orientation of the stretched film is not relaxed after stretching.

[Heat-shrinkable label and container equipped with the label]
The laminated body of the present invention can be molded or laminated as necessary with a printed layer, a vapor deposition layer, or other functional layers as various molded products such as a covering film such as a container, a binding band, and an exterior film. Can be used. In particular, when the laminate of the present invention is molded and used as a heat-shrinkable film for a heat-shrinkable label for food containers (for example, PET bottles, glass bottles, preferably PET bottles for soft drinks or foods). A container with a beautiful label without wrinkles, avatars, etc. that can be in close contact with the shape even if it has a shape (for example, a cylinder with a narrow center, a square column with a corner, a pentagonal column, a hexagonal column, etc.) can get.

  When the laminate of the present invention is formed into a heat-shrinkable film, it has excellent low-temperature shrinkage and shrinkage finishing properties. Therefore, the heat-shrinkable label material (base material) of a plastic molded product that is deformed when heated to a high temperature. In addition, materials having extremely different coefficients of thermal expansion and water absorption from the laminate of the present invention, such as metals, porcelain, glass, paper, polyethylene, polypropylene, polybutene and other polyolefin resins, polymethacrylate resins, Suitable for use as a heat-shrinkable label material (base material) for a package (container) using at least one selected from polycarbonate resins, polyethylene resins such as polyethylene terephthalate, polybutylene terephthalate, and polyamide resins as a constituent material it can.

  Examples of the material constituting the plastic package that can use the laminate of the present invention include polystyrene, rubber-modified high impact polystyrene (HIPS), styrene-butyl acrylate copolymer, and styrene-acrylonitrile copolymer in addition to the above-mentioned resins. , Styrene-maleic anhydride copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), (meth) acrylic acid-butadiene-styrene copolymer (MBS), polyvinyl chloride resin, phenol resin, urea resin, A melamine resin, an epoxy resin, an unsaturated polyester resin, a silicone resin, etc. can be mentioned, It can use individually or in combination of 2 or more types. The plastic package may be formed using a mixture of two or more resins, or may be a laminate of two or more layers.

  Examples of the laminate, stretched film, heat-shrinkable film, heat-shrinkable label and container equipped with the label of the present invention are shown below, but the present invention is not limited by these examples. In addition, the measured value and evaluation which are shown to an Example were performed as follows. In the examples, the take-up (flow) direction (direction orthogonal to the main shrinkage direction) when the laminate is formed into a film is described as “MD”, and the direction orthogonal thereto (main contraction direction) is described as “TD”.

<Measurement method>
(1) Heat shrinkage rate The laminate is formed into a heat shrinkable film, and the obtained film is cut into a size of MD 30 mm and TD 100 mm (interval between original marks) to obtain a test piece. The test piece was immersed in a warm water bath at 80 ° C. for 10 seconds, and then the marked line interval (A) after being immersed in cold water at 23 ° C. for 30 seconds was measured, and the shrinkage rate was calculated by the following formula (1). .
Shrinkage rate (%) = 100 × (100−A) / 100 (1)

(2) Transparency (all haze)
Based on JIS K7105, the haze value of a film having a thickness of 40 μm was measured to evaluate transparency.
Evaluation criteria ◎: Haze value is 5% or less ○: Haze value is greater than 5% and 10% or less ×: Haze value is greater than 10%

(3) Interlaminar peel strength The laminate is formed into a heat-shrinkable film, the resulting film is cut into a size of MD15 mm × TD150 mm, a part of the second layer is peeled off from the TD end surface, and the peeled portion is formed on the second layer. The peeled portion is formed on each of the other layers, the peeled portion of the second layer and the peeled portion of the other layer are sandwiched between the chucks of the tensile tester, and the test speed is 100 mm / min with respect to the TD direction. A 180 degree peel test was performed. The average value at which the load obtained in the peel test became constant to some extent was defined as the delamination strength.
Evaluation criteria A: Delamination strength is 2 N / 15 mm width or more O: Delamination strength is 1 N / 15 mm width or more and less than 2 N / 15 mm width ×: Delamination strength is less than 1 N / 15 mm width

(4) Peeling evaluation during shrinkage <Peeling assessment 1 during shrinkage>
The laminate is formed into a heat-shrinkable film, the resulting film is slit to a width of TD235 mm, and both ends of the MD film are overlapped 10 mm by a bag making machine, and this film end surface is sealed with various solvents, and is cylindrical. A film was prepared. This cylindrical film was cut into 165 mm in a direction perpendicular to the width direction, attached to a cylindrical PET bottle with a capacity of 500 mL, and rotated in a contraction tunnel having a length of 3.2 m (3 zones) of the steam heating method. It was passed for about 5 seconds. The atmospheric temperature in the tunnel in each zone was controlled in the range of 70 to 105 ° C. (for example, 90 ° C.) by adjusting the amount of steam with a steam valve. After film coating, the following criteria were used for evaluation.
Evaluation Criteria A: The deviation width is 0% or more and less than 2% with respect to the overlapping width of the overlapping portions at both ends of the film.
○: The deviation width is 2% or more and 5% or less with respect to the overlapping width of the overlapping portions at both ends of the film.
X: The deviation width is larger than 5% with respect to the overlapping width of the overlapping portions at both ends of the film, and delamination occurs.

<Peeling evaluation 2 during shrinkage>
The laminate is molded into a heat-shrinkable film, the resulting film is slit to a width of TD235mm, and both ends of the MD film are overlapped by 10mm and bonded with a solvent in which THF and cyclohexane are mixed in half by volume. Was made. This cylindrical film was cut out with MD 30 mm, and the circumferential portion on the opposite side to the solvent adhesion portion was cut to produce a MD30 mm × TD225 mm strip-like film having a solvent adhesion portion at the center. Thereafter, the strip-shaped film was sandwiched between two metal frames fixed to a width of 130 mm while being loosened to TD143 mm. Further, the metal frame on which the film was fixed was immersed in a 95 ° C. hot water bath for 30 seconds, and then immersed in cold water at 23 ° C. for 30 seconds. The shrunken film was removed from the metal frame, and the state of the solvent adhesion portion of the film was evaluated according to the following criteria.
Evaluation Criteria A: The deviation width is 0% or more and less than 2% with respect to the overlapping width of the overlapping portions at both ends of the film.
○: The deviation width is 2% or more and 5% or less with respect to the overlapping width of the overlapping portions at both ends of the film.
X: The deviation width is larger than 5% with respect to the overlapping width of the overlapping portions at both ends of the film, and delamination occurs.

Example 1
As shown in Table 1, 40% by mass of styrene resin A (styrene / butadiene = 90/10 (% by mass), storage elastic modulus E ′ (0 ° C.): 3.15 × 10 ⁹ Pa, loss elastic modulus E ”Peak temperature: 55 ° C., hereinafter referred to as“ SBS-A ”) and 60% by mass of styrene resin B (styrene / butadiene = 76/24 (% by mass), storage elastic modulus E ′ (0 ° C.): 6 .89 × 10 ⁸ Pa, loss elastic modulus E ″ peak temperature: −74 ° C., MFR: 6.8, trade name DK-11, manufactured by Chevron Phillips, hereinafter referred to as “SBS-B”) Using the composition as a third layer, a polyester resin (copolymerized polyester comprising a dicarboxylic acid component of 100 mol% terephthalic acid, a glycol component of 70 mol% of ethylene glycol, and 30 mol% of 1,4-cyclohexanedimethanol ( The product name PETG SKYGREENS 2008 (manufactured by SK Chemical Co., Ltd.), hereinafter referred to as “PETG”) is used as the second layer, polyester elastomer A (polybutylene terephthalate-poly (tetramethylene oxide) glycol copolymer, 72% by mass of polybutylene terephthalate, Poly (tetramethylene oxide) glycol 28% by mass, poly (tetramethylene oxide) glycol polymerization degree 13, trade name Primalloy A1900N, manufactured by Mitsubishi Chemical Corporation, hereinafter referred to as “TPEE-A”) as the first layer, three Mitsubishi After melting and mixing the respective resins from a single screw extruder manufactured by Heavy Industries Co., Ltd. at a set temperature range of 210 ° C. to 230 ° C., the thickness of each layer is the second layer / first layer / third layer / first layer / second layer = Co-pressing from 3 types 5 layers die to be 30μm / 10μm / 120μm / 10μm / 30μm And, take-off at 60 ° C. of casting rolls, solidified by cooling with a width 300 mm, to obtain an unstretched laminated sheet with a thickness of 200 [mu] m. Next, the film is stretched 5.0 times in the transverse uniaxial direction at a preheating temperature of 93 ° C. and a stretching temperature of 90 ° C. using a film tenter manufactured by Kyoto Machine Co., Ltd., and then heat treated at 65 ° C. Obtained. The results of evaluating the obtained film are shown in Table 1.

(Example 2)
As the constitution of the resin composition used in the first layer in Example 1, polyester elastomer resin B (polybutylene terephthalate-poly (tetramethylene oxide) glycol copolymer, 74% by mass of polybutylene terephthalate, poly (tetramethylene) Oxide) glycol 26% by mass, poly (tetramethylene oxide) glycol polymerization degree 26, trade name Primalloy A1800NS, manufactured by Mitsubishi Chemical Corporation, hereinafter referred to as “TPEE-B”) An unstretched laminated sheet was obtained. Furthermore, this unstretched sheet was stretched by the same method as in Example 1 to obtain a heat-shrinkable laminated film. The results of evaluating the obtained film are shown in Table 1.

(Example 3)
As the constitution of the resin composition used in the first layer in Example 1, polyester elastomer resin C (polybutylene terephthalate-poly (tetramethylene oxide) glycol copolymer, 77% by mass of polybutylene terephthalate, poly (tetramethylene) Oxide) glycol 23% by mass, poly (tetramethylene oxide) glycol polymerization degree 13, trade name Primalloy B1900NS, manufactured by Mitsubishi Chemical Corporation, hereinafter referred to as “TPEE-C”) An unstretched laminated sheet was obtained. Furthermore, this unstretched sheet was stretched by the same method as in Example 1 to obtain a heat-shrinkable laminated film. The results of evaluating the obtained film are shown in Table 1.

Example 4
As the constitution of the resin composition used in the first layer in Example 1, polyester elastomer resin D (polybutylene terephthalate-poly (tetramethylene oxide) glycol copolymer, 84% by mass of polybutylene terephthalate, poly (tetramethylene) Oxide) glycol 16% by mass, poly (tetramethylene oxide) glycol polymerization degree 13, trade name Primalloy B1910N, manufactured by Mitsubishi Chemical Corporation, hereinafter referred to as “TPEE-D”) An unstretched laminated sheet was obtained. Furthermore, this unstretched sheet was stretched by the same method as in Example 1 to obtain a heat-shrinkable laminated film. The results of evaluating the obtained film are shown in Table 1.

(Example 5)
As the constitution of the resin composition used in the first layer in Example 1, polyester elastomer resin E (polybutylene terephthalate-poly (tetramethylene oxide) glycol copolymer, 71% by mass of polybutylene terephthalate, poly (tetramethylene) Oxide) glycol 29% by mass, poly (tetramethylene oxide) glycol polymerization degree 13, trade name Perprene P40H, manufactured by Toyobo Co., Ltd., hereinafter referred to as “TPEE-E”). A stretched laminated sheet was obtained. Furthermore, this unstretched sheet was stretched by the same method as in Example 1 to obtain a heat-shrinkable laminated film. The results of evaluating the obtained film are shown in Table 1.

(Example 6)
Except having changed into the mixed resin composition of 30 mass% of TPEE-B and 70 mass% of TPEE-C as a structure of the resin composition used by the 1st layer in Example 1, it is the same as that of Example 1. An unstretched laminated sheet was obtained by the method. Furthermore, this unstretched sheet was stretched by the same method as in Example 1 to obtain a heat-shrinkable laminated film. The results of evaluating the obtained film are shown in Table 1.

(Example 7)
Except having changed into the mixed resin composition of 40 mass% of TPEE-B and 60 mass% of TPEE-C as a structure of the resin composition used by the 1st layer in Example 1, it is the same as that of Example 1. An unstretched laminated sheet was obtained by the method. Furthermore, this unstretched sheet was stretched by the same method as in Example 1 to obtain a heat-shrinkable laminated film. The results of evaluating the obtained film are shown in Table 1.

(Example 8)
As shown in Table 1, as the resin constituting the third layer, SBS-A is 30% by mass, SBS-B is 45% by mass, PETG is 20% by mass, and TPEE-E is 5% by mass. Unstretched laminate by the same method as in Example 1 except that the composition was kneaded with a twin screw extruder and pelletized, and the resin composition used in the first layer was changed to TPEE-E. A sheet was obtained. Further, this unstretched sheet was stretched in the same manner as in Example 1 to obtain a heat-shrinkable film. The results of evaluating the obtained film are shown in Table 1.

(Comparative Example 1)
As shown in Table 1, a mixed resin of 40% by mass SBS-A and 60% by mass SBS-B is used as the third layer, and PETG is used as the second and first layers. Each resin is melt-mixed at a set temperature range of 210 ° C. to 230 ° C. from a company-made single screw extruder, and the thickness of each layer is second layer / first layer / third layer / first layer / second layer = 20 μm / It was coextruded from 3 types and 5 layers dies so as to be 10 μm / 120 μm / 10 μm / 20 μm, taken up by a cast roll at 60 ° C., and cooled and solidified to obtain an unstretched laminated sheet having a width of 300 mm and a thickness of 180 μm. Next, the film is stretched 5.0 times in the transverse uniaxial direction at a preheating temperature of 93 ° C. and a stretching temperature of 90 ° C., and then heat treated at 65 ° C., and a heat-shrinkable laminated film having a thickness of 36 μm. Got. The results of evaluating the obtained film are shown in Table 1.

(Comparative Example 2)
As the constitution of the resin composition used in the first layer in Example 1, polystyrene elastomer resin A (polystyrene-polyisoprene-polystyrene copolymer, polystyrene 20% by mass, trade name HIBLER 5125, manufactured by Kuraray Co., Ltd., hereinafter “ An unstretched laminated sheet was obtained in the same manner as in Example 1 except that it was changed to “TPS-A”. Furthermore, this unstretched sheet was stretched by the same method as in Example 1 to obtain a heat-shrinkable laminated film. The results of evaluating the obtained film are shown in Table 1.

(Comparative Example 3)
As the constitution of the resin composition used in the first layer in Example 1, polystyrene elastomer resin B (styrene-ethylene-butylene-styrene copolymer, polystyrene 30% by mass, trade name Tuftec H1041, manufactured by Asahi Kasei Chemicals Corporation, An unstretched laminated sheet was obtained in the same manner as in Example 1 except that it was changed to “TPS-B”. Furthermore, this unstretched sheet was stretched by the same method as in Example 1 to obtain a heat-shrinkable laminated film. The results of evaluating the obtained film are shown in Table 1.

(Comparative Example 4)
As the constitution of the resin composition used in the first layer in Example 1, modified polystyrene elastomer resin C (modified styrene-ethylene-butylene-styrene copolymer, 30% by mass of polystyrene, trade name Tuftec M1913, Asahi Kasei Chemicals Co., Ltd.) An unstretched laminated sheet was obtained in the same manner as in Example 1 except that the product was changed to “TPS-C”. Furthermore, this unstretched sheet was stretched by the same method as in Example 1 to obtain a heat-shrinkable laminated film. The results of evaluating the obtained film are shown in Table 1.

Example 9
For the heat-shrinkable laminated films used in Examples 3 to 8 and Comparative Examples 2 to 4, peeling was evaluated by the method of peeling evaluation 2 during shrinkage. The evaluation results are shown in Table 2.

  The heat-shrinkable film (Examples 1-8) obtained from the laminated body of this invention from Table 1 is a heat-shrinkable film (comparative example) which does not comprise the 1st layer with the resin composition containing a polyester-type elastomer. It can be seen that the delamination strength is higher than in 1). Moreover, when the heat-shrinkable film (Examples 1-8) obtained from the laminated body of this invention is compared with the laminated body (Comparative Examples 2-4) whose 1st layer is a resin layer containing a styrene resin. It can be seen that good delamination is maintained even after heat shrinkage. Moreover, also in the conditions (Peeling evaluation 2 at the time of shrinkage | contraction at the time of thermal shrinkage from Table 2), the heat-shrinkable film (Examples 3-8) obtained from the laminated body of this invention suppressed delamination. I understand that Furthermore, the transparency of the heat-shrinkable film (Examples 1 to 8) obtained from the laminate of the present invention from Table 1 is a resin composition containing a polyester-based elastomer between the second layer and the third layer. Even if a layer is interposed, no significant reduction in transparency occurs, and the film has transparency sufficient as transparency of a film for label use. Also, from Example 8, regarding the film that was attempted assuming a case where recycled products were mixed in the third layer, the delamination strength did not change, and transparency sufficient for labeling was also achieved. It is a film that has. From this, it can be seen that the laminate of the present invention has transparency and delamination strength superior to those of conventional films, and is optimal for a heat-shrinkable film.

  Since the laminate of the present invention has both excellent delamination strength and transparency, it can be suitably used for molded products that require heat shrinkage, particularly shrink labels and the like.

  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. However, it can be changed as appropriate without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and a laminate, stretched film, heat-shrinkable film, molded product, Shrinkable labels, containers equipped with such labels should also be understood as being within the scope of the present invention.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Film piece 2 2nd layer 4 1st layer 6 3rd layer 8 Overlapping part 8w Overlapping width 10 End face of 2nd layer 12 End face of 1st layer 14 End face of 3rd layer 16 Solvent seal part 18 Deviation part 18w Deviation width A One end B The other end

Claims (14)

A resin composition containing a polyester composition, a resin composition containing a polyester elastomer, a resin composition containing a modified polyester elastomer, or a mixed resin composition of these resin compositions as a main component, and a resin containing a polyester resin A laminate having at least a second layer composed mainly of the composition ;
The polyester elastomer or the polyester elastomer forming the modified polyester elastomer is a laminate containing 50% by mass or more of hard segments with respect to the total amount of hard segments and soft segments ,
After the laminate is stretched in at least one direction to produce a heat-shrinkable film, a test piece is collected from the heat-shrinkable film in a size of 150 mm in the main shrinkage direction and 15 mm in a direction perpendicular to the main shrinkage direction. Then, a part of the second layer is peeled off from the film end surface in the main shrinkage direction of the test piece to form a peeled portion on the second layer and a peeled portion on the first layer, respectively. When the 180 degree peel test is performed at a test speed of 100 mm / min with respect to the main shrinkage direction, the delamination strength is 1 N / 15 mm width or more. A laminate characterized by being.   The main component is a thermoplastic resin composition having a composition different from that of the resin composition constituting the second layer on the surface of the first layer opposite to the surface of the first layer on which the second layer is laminated. The laminated body of Claim 1 which has a 3rd layer comprised as follows.   After the laminate is stretched in at least one direction to produce a heat-shrinkable film, a test piece is collected from the heat-shrinkable film with a size of 235 mm in the main shrinkage direction and 500 mm in the direction perpendicular to the main shrinkage direction. The surface of the second layer on one end side in the direction orthogonal to the main contraction direction of the test piece and the surface of the third layer or the second layer on the other end side in the same direction are tested in parallel. Form a 10mm wide overlap on one piece, seal the solvent, cut out a 165mm long cylindrical film in a direction perpendicular to the main shrinkage direction, and shrink it in a steam tunnel at 90 ° C for 5 seconds. When the temperature is returned to room temperature, the gap width between the end face of the second layer and the end face of the first layer and the third layer in the direction orthogonal to the main shrinkage direction sealed in the overlapping portion, or the main shrinkage A second layer in a direction perpendicular to the direction The end surface of the first layer, the deviation width between the end face of the third layer laminate according to claim 2 is within 5% of the overlapping width of the overlapping portions.   After the laminate is stretched in at least one direction to produce a heat-shrinkable film, a test piece is collected from the heat-shrinkable film with a size of 235 mm in the main shrinkage direction and 500 mm in the direction perpendicular to the main shrinkage direction. The surface of the second layer on one end side in the direction orthogonal to the main contraction direction of the test piece and the surface of the third layer or the second layer on the other end side in the same direction are parallel to each other on the test piece. After forming a 10 mm wide overlapping portion and solvent-sealing, a cylindrical film having a circumference of 225 mm in the main shrinkage direction and a length of 30 mm in a direction perpendicular to the main shrinkage direction was cut out, and then the cylindrical film When immersed in 95 ° C. warm water for 30 seconds with both ends sandwiched, the end face of the second layer in the direction orthogonal to the main contraction direction sealed in the overlapping portion, the first layer, End face of the third layer Or the gap width between the end faces of the second layer and the first layer in the direction orthogonal to the main shrinkage direction and the end face of the third layer is within 5% of the overlap width of the overlapping portion. The laminate according to claim 2.   The laminate according to any one of claims 2 to 4, wherein the third layer is a layer composed mainly of a resin composition containing a polystyrene-based resin.   6. The polystyrene resin according to claim 5, wherein the polystyrene resin is a block copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon, or a mixture of a block copolymer of a styrene hydrocarbon and a conjugated diene hydrocarbon. Laminated body.   The third layer is a resin composition containing a polyester resin constituting the second layer, or a resin composition containing a polyester elastomer constituting the first layer, a resin composition containing a modified polyester elastomer, Or it is a layer which contains these mixed resin compositions by the content rate of 40 mass% or less with respect to the total amount of the resin composition which comprises a 3rd layer, The laminated body of any one of Claim 2 to 6 .   The polyester resin is composed of a dicarboxylic acid component and a diol component, and at least one of the dicarboxylic acid component and the diol component is composed of two or more components, and the most numerous components are excluded from the two or more components. The total content of the components is 10 mol% or more and 50 mol% 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. The laminate according to any one of claims 1 to 7, which is as follows.   The laminate according to any one of claims 1 to 8, wherein a haze value based on JIS K7105 is 10% or less.   A stretched film obtained by stretching the laminate according to any one of claims 1 to 9 in at least one direction.   The laminate according to any one of claims 1 to 9 is stretched in at least one direction, and has a thermal shrinkage rate of 20% or more in the main shrinkage direction when immersed in warm water at 80 ° C for 10 seconds. A heat-shrinkable film.   A molded body obtained by molding the laminate according to any one of claims 1 to 9, the stretched film according to claim 10, and the heat-shrinkable film according to claim 11.   A heat-shrinkable label comprising the heat-shrinkable film according to claim 11 as a substrate.   A container equipped with the heat-shrinkable label according to claim 13.

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