JP2010120166A - Heat-shrinkable laminated film and heat-shrinkable label using the film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-shrinkable laminated film which maintains the shrunken finish properties of a film including a polyester resin without spoiling the properties, has good perforation cutting properties of the film, and is suitable for label applications and a heat-shrinkable label using the film. <P>SOLUTION: The heat-shrinkable laminated film has at least three layers including an intermediate layer and surface layers on both sides of the intermediate layer. The intermediate layer includes at least one polyolefin resin, and the surface layers include a polyester resin. The heat-shrinkable laminated film has a thermal shrinkage percentage in the main shrinkage direction when immersed in water of 70°C for 10 s of at least 20% and a thermal shrinkage percentage in the main shrinkage direction when immersed in water of 80°C for 10 s of at least 50%. The heat-shrinkable label is prepared by using the laminated film. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat-shrinkable laminated film and a heat-shrinkable label using the film. More specifically, a heat-shrinkable laminated film suitable for label use, which maintains a film made of a polyester-based resin without impairing the shrink finish of the film and has a good film perforation cut ability, and heat using the film A shrinkable label is provided.

  Currently, in the heat-shrinkable film field, especially for bottles of soft drinks such as juices, and shrink film for labels on the body of PET bottles, printing has been performed for the purpose of differentiation from other products and improved product visibility. Polyvinyl chloride heat-shrinkable films, polystyrene heat-shrinkable films, and polyethylene heat-shrinkable films are mainly used. However, the polyvinyl chloride heat-shrinkable film is not preferred because it has a problem of generating chlorine-based gas that is harmful when incinerated at the time of disposal. On the other hand, polystyrene-based heat-shrinkable film has better shrinkage finish than polyvinyl chloride-based heat-shrinkable film, but there are problems such as large natural shrinkage and large changes in physical properties over time, and the film mounting process is low due to low film stiffness. In this case, there is a problem that a mounting failure occurs due to a broken label. In addition, polyethylene-based heat-shrinkable films are difficult to adapt to bottles and PET bottles with complex shapes due to their low shrinkage rate. There is a problem that the printability is inferior, and improvement is also desired for this.

In order to solve the above drawbacks, polyester heat-shrinkable films have been used in recent years. However, many polyester-based heat-shrinkable films shrink rapidly, and wrinkles, shrinkage spots and distortions remain after shrinking, resulting in poor shrinkage finish. A method has been proposed in which the breaking elongation in the perpendicular direction is remarkably reduced (see Patent Document 1). In addition, a method for reducing the orientation return stress has been disclosed, and the shrinkage finish has been improved (see Patent Document 2). Furthermore, a method of adjusting the glass transition point (hereinafter also referred to as “Tg”) of a polyester resin used for a polyester heat-shrinkable film to a low level and using a C3-C6 diol component in the polyester resin is disclosed, and further shrinkage is disclosed. Finishability has been improved (see Patent Document 3).
Japanese Patent Laid-Open No. 1-110931 JP 58-64958 A JP-A-11-207818

  On the other hand, interest in recycling PET bottles has increased socially due to increased awareness of global environmental issues. With regard to PET bottle recycling so far, it is usually collected from general consumers with a label attached and brought to a recycler. The brought-in PET bottle is subjected to label removal by temporary pulverization after washing, but a large amount of labels are contained in the pulverized product. Therefore, recycled pellets were obtained through processes such as secondary grinding, separation of specific gravity of labels, dehydration, and drying. In recent PET bottle recycling processes, in order to increase the efficiency of label removal, it is becoming mainstream to first remove labels from PET bottles after washing and then pulverize them to obtain recycled pellets. In the above process, a perforated label is used to facilitate removal of the label from the PET bottle, and the actual label removal operation is achieved by removing the label along the perforation. became. In addition, it is becoming common practice for each local government to voluntarily remove labels when separating and collecting PET bottles in each local government, and labels with perforations can be easily removed from bottles or PET bottles. Needed.

  Therefore, the heat-shrinkable film is one of the important qualities that it is excellent in perforation cut property after shrinkage treatment, and it is necessary to satisfy it. However, the polyester-based heat-shrinkable film obtained by the above-described method is extremely inferior in perforation cut property after shrinkage treatment, and it is extremely difficult to peel it cleanly along the perforation, and improvement is urgently required. .

As a method for solving the above disadvantages, a polyolefin-based heat-shrinkable film has been developed (see Patent Document 4). Polyolefin-based heat-shrinkable film has excellent perforation cutability and can solve the problems associated with polyester-based heat-shrinkable film, but because the shrinkage rate is low, there are restrictions on the shape, design, design, etc. of bottles that can be used. There was a problem. Moreover, if cyclic polyolefin is used as the polyolefin heat-shrinkable film, the shrinkage rate can be increased to some extent, but the raw material cost increases, which is not preferable as an industrial product produced in large quantities. Further, since the polyolefin-based heat-shrinkable film has a larger natural shrinkage than the polyester-based heat-shrinkable film, this point is not satisfactory as a heat-shrinkable film.
JP 2001-219503 A

  The present invention relates to a heat-shrinkable laminated film and a heat-shrinkable label using the film. More specifically, it is intended to provide a heat-shrinkable laminated film suitable for label applications and a heat-shrinkable label using the film, which maintains a shrink finish and has good film perforation cutability. .

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have maintained the shrinkage characteristics of the polyester heat-shrinkable film, and have good perforation cutability of the film, and further substantially. The present inventors have found that a heat-shrinkable laminated film suitable for labeling applications useful for the present invention and a heat-shrinkable label using the film can be obtained.

That is, this invention consists of the following structures.
1. A heat-shrinkable laminated film comprising at least three layers having a surface layer on both sides of the intermediate layer and the intermediate layer, the intermediate layer comprising at least one polyolefin resin, and the surface layer being composed of a polyester resin The thermal contraction rate in the main contraction direction when immersed in warm water at 70 ° C. for 10 seconds is 20% or more, and the thermal contraction rate in the main contraction direction when immersed in warm water at 80 ° C. for 10 seconds is 50% or more. A heat-shrinkable laminated film characterized by being.
2. 2. The heat-shrinkable laminated film as described in the above item 1, wherein the elongation at break in the direction perpendicular to the main shrinkage direction of the film is 600% or less and the breaking strength is 40 MPa or less.
3. The heat-shrinkable laminated film according to the first or second aspect, wherein the intermediate layer and the surface layer are in direct contact with each other without an adhesive layer.
4). The heat-shrinkable label using the heat-shrinkable laminated film in any one of the said 1st-3rd as a base material.

  According to the present invention, there is provided a heat-shrinkable laminated film suitable for label use, which has good film perforation cutability while maintaining good shrinkage finish, and a heat-shrinkable label using the film. Can be provided.

  The present invention is a heat-shrinkable laminated film comprising an intermediate layer and at least three layers having a surface layer on both sides of the intermediate layer, wherein the intermediate layer comprises at least one polyolefin-based resin, and the surface layer is a polyester. The heat shrinkage rate in the main shrinkage direction is 20% or more when immersed in warm water at 70 ° C. for 10 seconds, and the heat shrinkage rate in the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds. It is a heat-shrinkable laminated film characterized by being 50% or more, and the film is preferably produced by co-extrusion and co-stretching, and the film can be obtained substantially in one production process. Excellent productivity. In addition, the heat-shrinkable laminated film of the present invention can be easily sealed because the surface layer present on both sides of the intermediate layer has a polyester-based resin when a center seal is applied at the time of label production. Can be strongly stabilized.

  In the present invention, the polyolefin resin of the intermediate layer has a function excellent in perforation cutability, and the polyester resin of the surface layer present on both sides of the intermediate layer has a good shrinkage characteristic function, so that both functions are compatible. Thus, it is possible to obtain a heat-shrinkable laminated film suitable for label use and a heat-shrinkable label using the film. In addition, since the surface layer is formed of a polyester-based resin, it has moderate heat resistance, so that it can be suitably used for labeling hot drink PET bottles.

  The heat-shrinkable laminated film of the present invention has a heat shrinkage rate of at least 20% when immersed in warm water at 70 ° C. for 10 seconds, and at least when immersed in warm water at 80 ° C. for 10 seconds. It is preferable that the heat shrinkage rate in one direction is 50% or more. The thermal shrinkage ratio in at least one direction when immersed in warm water at 70 ° C. for 10 seconds is more preferably 25% or more, and further preferably 30% or more, and when immersed in warm water at 80 ° C. for 10 seconds. The thermal shrinkage rate in at least one direction is more preferably 55% or more, and still more preferably 58% or more.

  When the thermal shrinkage rate is less than 20% in both directions when immersed in warm water at 70 ° C for 10 seconds, or when the thermal shrinkage rate is less than 50% in both directions when immersed in warm water at 80 ° C for 10 seconds Alternatively, when an object to be packaged such as a bottle is packaged and passed through a contraction tunnel, the end portion becomes wide like a petal, and contraction spots and wrinkles are easily generated, which is not preferable. However, if the thermal shrinkage rate is too large, this may also cause shrinkage spots. Therefore, the thermal shrinkage rate when immersed in 70 ° C. warm water in the main shrinkage direction for 10 seconds is 50% or less. The thermal shrinkage rate when immersed in 70 ° C. warm water in the main shrinkage direction for 10 seconds is preferably 80% or less.

  Furthermore, the heat-shrinkable laminated film of the present invention preferably has a breaking elongation of 600% or less and a breaking strength of 40 MPa or less in a direction perpendicular to the main shrinking direction.

  When the elongation at break in the direction perpendicular to the main shrinkage direction is greater than 600% and the break strength is greater than 40 MPa, the perforation cut after the perforation is put in the label made from the obtained film and contracted to a PET bottle or the like Poor property is not preferable. That is, when the label is torn along the perforation, a strong resistance is generated in the hand, and a portion gripped by the hand extends without being along the perforation, and the tab is cut off in the middle. In order to improve the perforation cutability of the heat-shrinkable laminated film of the present invention, it is preferable that the breaking elongation in the direction perpendicular to the main shrinking direction is 600% or less and the breaking strength is 40 MPa or less. More preferably, the breaking elongation in the direction orthogonal to the main shrinkage direction is 550% or less and the breaking strength is 35 MPa or less. However, if the elongation at break in the direction orthogonal to the main shrinkage direction is too small, brittleness is generated, so it may be 400% or more. For the same reason, the breaking strength may be 20 MPa or more.

  The elongation at break and the strength at break here mean values measured according to JIS C-2318 method.

  In the heat-shrinkable laminated film of the present invention, the intermediate layer is composed of a layer mainly composed of a polyolefin resin. The polyolefin resin used in the film of the present invention is not particularly limited. Usable polyolefin resins include ethylene resins such as polyethylene resins, polypropylene resins, ethylene-vinyl acetate copolymers, and ethylene-ethyl acrylate copolymers. Especially, it is preferable to use a polyethylene-type resin, a polypropylene-type resin, or these mixtures from a viewpoint of a heat shrinkage rate and a finishing property. Since there are various types of polyethylene resins and polypropylene resins depending on the polymerization method and copolymerization component, the range is not particularly limited.

As the polyethylene resin used in the present invention, a high density polyethylene resin (HDPE) having a normal density of 0.94 g / cm ³ or more and 0.97 g / cm ³ or less, a density of 0.92 g / cm ³ or more and 0.94 g / cm ³ or less in density polyethylene resin (MDPE), density of 0.92 g / cm ³ less than the low-density polyethylene resin (LDPE) and linear low density polyethylene resin (LLDPE). Among these, linear low density polyethylene (LLDPE) is preferable from the viewpoints of stretchability, film impact resistance, and transparency.

  The film density here means a value measured at 30 ° C. by means of a density gradient tube method (for example, a calcium nitrate solution) or a floatation method.

  Next, examples of the polypropylene resin used in the present invention include homopropylene resin, random polypropylene resin, block polypropylene resin, and propylene-ethylene rubber. Among these, a random polypropylene resin is preferable from the viewpoint of stretchability, transparency, rigidity, and the like.

  The melt flow rate (MFR) of the polypropylene-based resin is not particularly limited, but it is usually preferable that the MFR is 0.5 g / 10 min or more and 15 g / 10 min or less.

  The melt flow rate (MFR) here is a measurement method based on JIS K7210, and means a value measured at a temperature of 230 ° C. and a load of 2.16 Kg.

  More specifically, these polyethylene-based resins and polypropylene-based resins are the polyethylene-based resins having the trade names “Novatech (registered trademark) HD, LD, LL”, “Kernel (registered trademark)”, “Toughmer A, P” (Japan) Polyethylene), “Suntec (registered trademark) HD, LD” (manufactured by Asahi Kasei Chemicals), “HIZEX (registered trademark)”, “ULTZEX (registered trademark)”, “EVOLUE (registered trademark)” (manufactured by Mitsui Chemicals), It is commercially available as “MORE-TEX (registered trademark)” (manufactured by Idemitsu Kosan Co., Ltd.), “UBE polyethylene (registered trademark)”, “UMERIT (registered trademark)” (manufactured by Ube Industries, Ltd.), and the like. In addition, as polypropylene resins, trade names “Novatech (registered trademark) PP”, “WINTEC (registered trademark)”, “Toughmer XR” (manufactured by Nippon Polypro), “Mitsui Polypro” (manufactured by Mitsui Chemicals), “Sumitomo Noblen ( "Registered Trademark)", "Tufselen (Registered Trademark)", "Exelen (Registered Trademark) EPX" (manufactured by Sumitomo Chemical Co., Ltd.), "IDEMITSU (Registered Trademark) PP", "IDEMITSU (Registered Trademark) TPO" (made by Idemitsu Kosan Co., Ltd.) It is commercially available. These copolymers can be used alone or in admixture of two or more.

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

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

The polyester resin constituting the present invention is a product obtained by direct esterification of terephthalic acid and ethylene glycol, and as a by-product, diethylene glycol, oligomer, cyclic oligomer, etc., and unreacted linear monomer or oligomer. Etc. may be included. The intrinsic viscosity of the polyester resin is preferably 0.55 to 1.30 dl / g, more preferably 0.60 to 1.20 dl / g. At this time, the resin density is preferably 1.350 to 1.450 g / cm ³ .

  Intrinsic viscosity here refers to 0.1 g of a chip sample that is precisely weighed, dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane = 6/4 (mass ratio), and measured at 30 ° C. using an Ostwald viscometer. . In addition, the measurement is performed three times, and means an average value.

  In the present invention, the polyester resin constituting the film may contain other copolymer components as long as the purpose is not impaired. Among other copolymerizable components that can be used, aromatic dicarboxylic acids such as naphthalenedicarboxylic acid, diphenylsulfone dicarboxylic acid, 5-sodium sulfoisophthalic acid, oxalic acid, succinic acid, adipic acid, sebacic acid, decane Aliphatic dicarboxylic acids such as dicarboxylic acid, maleic acid, fumaric acid and dimer acid, oxycarboxylic acids such as p-oxybenzoic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid can be used. As glycol components, aliphatic glycols such as propanediol, butanediol, pentanediol, hexanediol and neopentylglycol, alicyclic glycols such as cyclohexanedimethanol, ethylene oxide adduct of bisphenol A, ethylene oxide of bisphenol S Aromatic glycols such as adducts, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like can be used. In addition, a small amount of a compound containing an amide bond, a urethane bond, an ether bond, a carbonate bond, or the like may be included. As used herein, the resin having substantially polyethylene terephthalate as a main component means a resin in which 90 mol% or more of constituent components are preferably composed of ethylene terephthalate units, and more preferably 95 mol% or more.

  The polyester resin can be produced by a conventional method. Examples include a direct esterification method in which an acidic component and a glycol component are directly reacted, and a transesterification method in which an ester as an acid component is reacted with a glycol component, but are not particularly limited.

  The polyester-based resin may contain various additives as necessary. Additives include titanium dioxide, fine particle silica, kaolin, calcium carbonate, and other inorganic lubricants, and fine particle materials made of acrylic cross-linked polymers, such as acrylic acid, methacrylic acid, acrylic ester, and methacrylic ester. Examples thereof include organic lubricants such as cross-linked polymers made of monomers. Moreover, an antistatic agent, an anti-aging agent, an ultraviolet light inhibitor, a colorant, a dye and the like may be contained alone, or two or more kinds may be used in combination.

In the present invention, fine particle silica is preferable as the additive, but is not particularly limited. The composition of the fine-particle silica is mainly composed of silicon dioxide (SiO ₂ ), and the shape may be any shape such as indefinite shape, spherical shape, and agglomerated shape, but in the present invention, the indefinite shape having no crystal structure. Is preferred. Further, the average particle size (silica fine particles are dispersed in ion-exchanged water stirred at a predetermined rotational speed (about 5000 rpm) using a high-speed stirrer, and the dispersion is added to isotone (physiological saline). The particle size distribution was obtained by the Coulter counter method, and the particle size at 50% of the weight cumulative distribution was calculated as the average particle size.) Is preferably 1.4 to 4.5 μm, more preferably 1.8. ˜3.0 μm. If the average particle size is less than 1.4 μm, blocking between the films occurs, which becomes a problem. On the other hand, when the average particle size is larger than 4.5 μm, there arises a problem that fine silica particles are dropped during film processing and a problem that scratch resistance is deteriorated. In the present invention, silicia manufactured by Fuji Silysia Co., Ltd. (grade: 310P, shape: amorphous, average particle size: 2.7 μm) was used.

  The heat-shrinkable laminated film of the present invention is obtained by, for example, casting various resins melt-kneaded by a plurality of extruders by co-extrusion from a T-die and cooling and solidifying to obtain an unstretched film. It is preferable to stretch at a temperature of 5 ° C. or more and less than Tg + 15 ° C. Extrusion conditions can be selected as appropriate and are not particularly limited.

  The heat-shrinkable laminated film of the present invention may have a plurality of layers containing an intermediate layer resin such as an adhesive layer used for the purpose of suppressing delamination, for example, on both sides or one side of the intermediate layer. However, if the polyolefin-based resin as described above is used for the surface layer, it is possible to obtain practically usable integrity without an adhesive layer, and it is particularly preferable to use “Tufselen (registered trademark)” manufactured by Sumitomo Chemical Co., Ltd. Unity can be obtained.

  When the heat-shrinkable laminated film of the present invention is stretched at a temperature lower than Tg-5 ° C. of the polyester-based resin, not only is it difficult to obtain the heat shrinkage rate that is a constituent of the present invention, but the transparency of the obtained film is also high. Since it gets worse, it is not preferable. Further, stretching at a temperature of Tg + 15 ° C. or more is not preferable because the elongation at break in the direction perpendicular to the main shrinkage direction after the shrinkage treatment of the obtained film is remarkably lowered. The draw ratio is preferably 3 to 6 times, but is not particularly limited.

  Although the total thickness of the heat-shrinkable laminated film of the present invention is not particularly limited, it is preferably thinner from the viewpoint of transparency, shrinkage workability, raw material cost, and the like. Specifically, the total film thickness after stretching is 80 μm or less, preferably 70 μm or less. The lower limit of the total thickness of the heat-shrinkable laminated film is not particularly limited, but is preferably 10 μm or more in consideration of the handling properties of the film. In addition, the thickness of each layer constituting the heat-shrinkable laminated film can be freely set within a range not hindering the present invention, but from the viewpoint of perforation cutting property, the thickness of the intermediate layer is preferably the entire thickness. 15% or more, more preferably 20% or more. From the viewpoint of heat shrinkage characteristics, the thickness of the one-side surface layer is preferably 15% or more, more preferably 20% or more of the total thickness.

  The heat-shrinkable laminated film of the present invention is subjected to surface treatment by a conventionally known method such as corona discharge treatment, plasma treatment, ozone treatment, chemical treatment, or anchor treatment using a known anchor treatment agent, depending on the purpose. May be given

  The heat-shrinkable laminated film of the present invention is not particularly limited as long as it is an antistatic coating agent such as alkyl sulfonic acid, glycerin ester, polyglycene ester, etc., and can impart antistatic properties. The coating method is not particularly limited as long as it is a conventionally known method such as a berth roll coating method, a roll knife coating method, a die coating method, or a gravure coating method. Furthermore, it may be a coating by in-line coating.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited by these Examples. In addition, the measuring method of the physical property of the film obtained by the Example and the comparative example is as follows.

(1) Thermal shrinkage The film was cut into a size of 100 mm in the length (flow direction) and 100 mm in the width (direction perpendicular to the length), and immersed in a hot water bath at 70 ° C. and 80 ° C. for 10 seconds, and the shrinkage was measured. . For the shrinkage, the ratio of the shrinkage to the original size before shrinkage was expressed as a% value.

(2) Shrink-up property A heat-shrinkable laminated film is printed in advance with Toyo Ink Mfg. Co., Ltd.'s grass, gold, and white color prints, and both ends of the film are bonded with dioxolane to form a cylindrical label (main shrinkage). Made the service in the circumferential direction). Thereafter, using a steam tunnel (model: SH-1500-L) manufactured by Fuji Astec Inc., passing through a 2.5-second zone temperature of 80 ° C., heating a 500 ml PET bottle (bottle diameter: 62 mm, minimum neck diameter: 25 mm). Implemented by shrinking. The evaluation criteria were classified and evaluated as follows.
○: Wrinkles, jumping up, insufficient shrinkage did not occur △: Wrinkles, jumping up, insufficient shrinkage occurred slightly: Wrinkles, jumping up, insufficient shrinkage occurred

(3) Melt flow rate (MFR)
Melt flow rate (MFR) is a measuring method based on JIS K7210, and means a value measured at a temperature of 230 ° C. and a load of 2.16 Kg.

(4) Glass transition point (Tg)
The measurement was performed by connecting a TA60WS disk station (manufactured by Shimadzu Corporation) to a robot DSC (differential scanning calorimeter) DSC-60 (manufactured by Shimadzu Corporation). After 5 mg of the sample was adjusted to an aluminum pan, it was set in a DSC apparatus (reference: the same type of aluminum pan without a sample), and this sample was heated from −40 ° C. to 120 ° C. at a rate of 10 ° C./min. A tangent line was drawn before and after the inflection point from the DSC chart, and the intersection was determined as the glass transition point (Tg).

(5) Intrinsic Viscosity 0.1 g of a chip sample was precisely weighed and dissolved in 25 ml of a mixed solvent of phenol / tetrachloroethane = 6/4 (mass ratio), and measured at 30 ° C. using an Ostwald viscometer. The measurement was performed three times and the average value was obtained.

(6) Density Density was measured at 30 ° C. with a density gradient tube obtained by adjusting the concentration of a calcium nitrate solution.

(7) Average particle diameter The volume median diameter of the aqueous dispersion of the sample was measured using a Coulter Counter Multisizer II (manufactured by Beckman Coulter, Inc.).

(8) Breaking strength and breaking elongation The breaking strength and breaking elongation were measured according to JIS C-2381 method. At this time, the tensile speed of the test piece was 200 mm / min.

(9) Perforation cutting property A label having a perforation in a direction perpendicular to the main shrinkage direction was attached to a PET bottle under the same conditions as those for measuring the shrinkage finish. However, the perforations were formed by inserting holes with a length of 1 mm at intervals of 1 mm, and two perforations having a width of 22 mm and a length of 120 mm were provided in the longitudinal direction (flow direction) of the label. The bottle is then filled with 500 ml of water, refrigerated to 5 ° C, and immediately after removal from the refrigerator, the label perforation is torn with the fingertips, and the label is removed from the PET bottle. The number of completed samples was counted and calculated as a ratio (%) to the total number of samples of 50.

Example 1
Copolymerized polyester resin (A) could be prepared using 100 mol% terephthalic acid as the acid component, 70 mol% ethylene glycol and 30 mol% neopentyl glycol as the glycol component. The glass transition temperature of (A) was 75 ° C., and the intrinsic viscosity was 0.72 dl / g. Silica (Fuji Silysia Corp. Silicia (grade: 310P, shape: amorphous, average particle size: 2.7 μm) is added as an additive to polyethylene terephthalate (inherent viscosity is 0.63 dl / g) to 1000 ppm. A terephthalate resin composition (B) was obtained, which was mixed as a polyester resin at (A) = 70 wt% and (B) = 30 wt% (C) .The polyolefin resin (D) was manufactured by Sumitomo Chemical Co., Ltd. Tough selenium (registered trademark) "(grade: H5002) melted and kneaded in separate extruders, supplied to a T die, extruded from the inside of the T die to a resin temperature of 275 ° C, and further The film was cast with a casting roll at a temperature of 25 ° C. Then, the film was 4.1 times tenter at 74 ° C. in one direction (lateral direction). Stretched and then annealed in the same tenter at 80 ° C. for 5 seconds, and the thickness of each layer becomes (C) / (D) / (C) = 10 μm / 20 μm / 10 μm. Got.

(Example 2)
The same procedure as in Example 1 was performed except that (A) = 55 wt% and (B) = 45 wt% were mixed as the polyester resin.

(Example 3)
The same procedure as in Example 1 was performed except that the thickness of each layer of the heat-shrinkable laminated film was (C) / (D) / (C) = 16 μm / 8 μm / 16 μm.

(Comparative Example 1)
A polyester-based resin (A) = 70% by weight and (B) = 30% by weight mixed with (C) melted and kneaded is supplied to the T die so that the resin temperature is 275 ° C. from the inside of the T die. Extrusion was further performed using a casting roll at a temperature of 25 ° C. Thereafter, the film was stretched 4.1 times in one direction (lateral direction) at 74 ° C. and then annealed in the tenter at 80 ° C. for 5 seconds, and heat shrinkability by lateral uniaxial stretching to give a thickness = 40 μm. A film was obtained.

(Comparative Example 2)
The same procedure as in Example 1 was performed except that the thickness of each layer of the heat-shrinkable laminated film was (C) / (D) / (C) = 18 μm / 4 μm / 18 μm.

  The heat-shrinkable laminate film of the present invention and the heat-shrinkable label using the film are practically used while maintaining the shrink finish of a film made of a polyester resin and having good perforation cutability of the film. Heat shrinkable laminated film suitable for labeling bottles or PET bottles, and labeling as a heat-shrinkable label using the film. It can be widely used in various fields and contributes greatly to the industry.

Claims (4)

  A heat-shrinkable laminated film comprising at least three layers having a surface layer on both sides of the intermediate layer and the intermediate layer, the intermediate layer comprising at least one polyolefin resin, and the surface layer being composed of a polyester resin The thermal contraction rate in the main contraction direction when immersed in warm water at 70 ° C. for 10 seconds is 20% or more, and the thermal contraction rate in the main contraction direction when immersed in warm water at 80 ° C. for 10 seconds is 50% or more. A heat-shrinkable laminated film characterized by being.   The heat-shrinkable laminated film according to claim 1, wherein the elongation at break in a direction perpendicular to the main shrinkage direction of the film is 600% or less and the break strength is 40 MPa or less.   The heat-shrinkable laminated film according to claim 1 or 2, wherein the intermediate layer and the surface layer are in direct contact with each other without an adhesive layer.   The heat-shrinkable label using the heat-shrinkable laminated film in any one of Claims 1-3 as a base material.