WO2008018528A1

WO2008018528A1 - Package

Info

Publication number: WO2008018528A1
Application number: PCT/JP2007/065586
Authority: WO
Inventors: Masayuki Haruta; Masakazu Iwasaki; Masatoshi Hashimoto; Katsuhiko Nose
Original assignee: Toyo Boseki Kabushiki Kaisha
Priority date: 2006-08-09
Filing date: 2007-08-09
Publication date: 2008-02-14

Abstract

[PROBLEMS] To provide a package covered with a label formed from a heat-shrinkable film and having satisfactory tearableness. [MEANS FOR SOLVING PROBLEMS] The heat-shrinkable polyester film for label formation shrinks mainly in the machine direction. It has been regulated so as to have the following properties in respective given ranges: the degree of machine-direction hot-water thermal shrinkage through 10-second immersion in 90°C water; degree of transverse-direction hot-water thermal shrinkage through 10-second immersion in 90°C water; transverse-direction angle tear strength after 10% machine-direction shrinkage through immersionin 80°C water; Elmemdorf ratio determined through an Elmendorf tear load measurement made after 10% machine-direction shrinkage in 80°C water; and degree of natural shrinkage through 700-hour or longer aging in an atmosphere of 40°C and 65% RH.

Description

Specification

Package

Technical field

TECHNICAL FIELD [0001] The present invention relates to a packaging body coated with a label formed of a heat-shrinkable film, and more particularly to a packaging body having a good tearing condition of a label made of a coated heat-shrinkable film. is there.

Background art

[0002] In recent years, many packagings have been heat-shrinked on the outside of containers such as glass bottles and plastic bottles by covering them with plastic film labels for the purpose of protecting the contents, improving the appearance, and displaying the contents. It is becoming visible. Examples of such heat-shrinkable plastic films for labels include heat-shrinkable polyester films, heat-shrinkable polystyrene films, heat-shrinkable polyolefin films, and heat-shrinkable poly (vinyl chloride) films. Many used!

[0003] Further, as a normal heat-shrinkable plastic film, a film that is greatly shrunk in the width direction is widely used. In such a heat-shrinkable plastic film whose width direction is the main shrinkage direction, the film is stretched at a high magnification in the width direction in order to develop shrinkage characteristics in the width direction, but is orthogonal to the main shrinkage direction. With respect to the longitudinal direction, there are some that are only stretched at a low magnification and that are often not stretched. As described above, a film that has been stretched at a low magnification in the longitudinal direction or a film that has been stretched only in the width direction has a drawback that the mechanical strength in the longitudinal direction is inferior.

[0004] In addition, since the label of the bottle has to be circularly attached to the bottle and then thermally shrunk in the circumferential direction, when a heat-shrinkable film that thermally shrinks in the width direction is attached as a label, An annular body must be formed so that the width direction of the ring is the circumferential direction, and the annular body must be cut into a predetermined length and attached to the bottle. Therefore, it is difficult to attach a label made of a heat-shrinkable film that shrinks in the width direction to the bottle at a high speed. Therefore, recently, there is a need for a film that thermally shrinks in the longitudinal direction that can be mounted directly from the film roll around the bottle. Furthermore, in recent years, lunch boxes, etc. A lapping method has been developed to hold the container in a closed state by covering the periphery of a single-open container made of synthetic resin with a belt-like film, and a film that shrinks in the longitudinal direction is suitable for such packaging applications. ing. Therefore, demand for films that shrink in the longitudinal direction is expected to increase dramatically in the future.

[0005] A non-stretched film that eliminates the mechanical strength defect in the direction orthogonal to the main shrinkage direction as described above and develops a function of shrinking in the longitudinal direction is referred to as the longitudinal direction (also referred to as the longitudinal direction). Stretch in the longitudinal direction by stretching 2.0 to 5.0 times each in the width direction (also referred to as the transverse direction) and then re-stretching 1.1 times or more in the longitudinal direction. A heat-shrinkable polyester film is known in which both the Young's modulus and the Young's modulus in the width direction are adjusted to a predetermined value or more (Patent Document 1).

Patent Document 1: Japanese Patent Application Laid-Open No. 8-244114

Brief Description of Drawings

[0007] FIG. 1 is an explanatory view showing the shape of a test piece in the measurement of right-angled tear strength (the unit of length of each part of the test piece in the figure is mm).

Disclosure of the invention

Problems to be solved by the invention

[0008] However, although the heat-shrinkable polyester film of Patent Document 1 described above has good mechanical strength in the longitudinal direction and the width direction, the shrinkability in the longitudinal direction, which is the main shrinkage direction, is not necessarily sufficient. I can't say that. That is, the present inventors conducted a supplementary test at the Veg pilot plant (film width = 1 · 5 m) to obtain the heat-shrinkable polyester film of Patent Document 1, and obtained the heat-shrinkable polyester film of Patent Document 1. Although a certain degree of mechanical strength is exhibited in the longitudinal direction and the width direction, the shrinkage in the longitudinal direction, which is the main shrinkage direction, is not necessarily sufficient, and it is found that the thickness unevenness in the longitudinal direction is large. It was. In addition, since the natural shrinkage rate when left for a certain period of time at room temperature is large, there is a problem in that the roll-shaped film produced is tightly wound and the film roll is easily wrinkled. I understood. Furthermore, it was also found that the heat-shrinkable polyester film obtained by the above-described additional test has poor tearability (openability) when tearing along the direction perpendicular to the main shrinkage direction. And such unopenability In a package coated with a label made of a good heat-shrinkable polyester film, the resistance is high when the label is torn in the direction perpendicular to the main shrinkage direction, the label is stretched and cannot be torn well, When there is an eye, it is a component force that it causes a problem such as tearing at a position different from the perforation.

[0009] An object of the present invention is to solve the problems of the heat-shrinkable polyester film of Patent Document 1 described above, and in the width direction orthogonal to the main shrinkage direction in which the shrinkage in the longitudinal direction, which is the main shrinkage direction, is high. In addition to providing a heat-shrinkable film that has high mechanical strength and does not cause winding and tightening in the roll film produced, and that has a good opening property that makes it difficult for paper rolls to enter the film roll. It is intended to provide a package in which a label made of an adhesive film is coated and the bow of the label is cracked well.

Means for solving the problem

[0010] Among the present inventions described above, the invention described in claim 1 is a package formed by heat-shrinking at least a part of the outer periphery with a label having a heat-shrinkable film as a base material. The Elmendorf ratio when measuring the Elmendorf tear load in the direction perpendicular to the main shrinkage direction of the coated label and the Elmendorf tear load in the main shrinkage direction is 0.5 or more and 2.0 or less. To do. Examples of the heat-shrinkable film of the present invention include a heat-shrinkable polyester film, a heat-shrinkable polystyrene film, a heat-shrinkable polyolefin film, and a heat-shrinkable polychlorinated butyl film. Further, the perforation means that a plurality of slits are continuously provided in a linear shape or a curved shape, but includes one in which only one slit is provided. Furthermore, the shape of the slit constituting the perforation is not particularly limited. On the other hand, the notch refers to a notch provided at the edge of the label, and its shape is not particularly limited. In addition, the Elmendorf tear load in the direction perpendicular to the main shrinkage direction of the coated label or in the main shrinkage direction is the direction perpendicular to the main shrinkage direction of the film substrate excluding the printed layer of the coated label or the main shrinkage direction. The Elmendorf tear load in the direction of contraction.

[0011] The invention described in claim 2 is the invention described in claim 1, wherein the tensile fracture strength in the direction perpendicular to the main shrinkage direction of the coated label is not less than lOOMPa and not more than 300 MPa. It is characterized by. Note that the main shrinkage direction of the coated label The tensile breaking strength in the intersecting direction refers to the tensile breaking strength in the direction orthogonal to the main shrinkage direction of the film substrate excluding the printed layer of the coated label.

[0012] The invention described in claim 3 is orthogonal to the main shrinkage direction of the film substrate excluding the printed layer of the coated label in the invention described in claim 1 or claim 2. The refractive index in the direction is 1.570 or more and 1.600 or less.

[0013] The invention described in claim 4 is the invention described in any one of claims 1 to 3, wherein the right-angled tear strength in the direction perpendicular to the main shrinkage direction per unit thickness of the coated label. Is characterized by being 100 N / mm or more and 300 N / mm or less. The right-angle tear strength in the direction perpendicular to the main shrinkage direction per unit thickness of the coated label is the perforation main shrinkage per unit thickness of the film substrate excluding the printed layer of the coated label. This is the right-angle tear strength in the direction perpendicular to the direction.

[0014] The invention described in claim 5 is the invention described in any one of claims 1 to 4, wherein a perforation or a pair of notches is provided along a direction orthogonal to the main contraction direction of the label. It is characterized by that.

[0015] The invention described in claim 6 is the invention described in any one of claims 1 to 5, wherein the unstretched film is held in the tenter in a state where both ends in the width direction are held by clips. After stretching in the width direction at a temperature of 5 ° C or more and Tg + 40 ° C or less 2.5 times or more and 6.0 times or less, after passing through an intermediate zone where no aggressive heating operation is performed, 100 A process of heat treatment at a temperature not lower than 170 ° C and not higher than 170 ° C for a time not shorter than 1.0 second and not longer than 10.0 seconds, and then cooling until the surface temperature of the film reaches 30 ° C or higher and 70 ° C or lower And the clip gripping part at both edges in the width direction of the film is cut and removed, and stretched at a magnification of 2.0 times or more and 5.5 times or less in the longitudinal direction at a temperature of Tg + 50 ° C or more and Tg + 80 ° C or less After that, the film is cooled at a cooling rate of 30 ° C / second to 70 ° C / second until the surface temperature of the film reaches 45 ° C to 75 ° C. The heat-shrinkable film before forming the label is manufactured! /, It is characterized in Rukoto.

[0016] The invention described in claim 7 is the invention described in any one of claims 1 to 6, wherein the heat-shrinkable film is a heat-shrinkable polyester film. It is.

The invention's effect

[0017] The heat-shrinkable film used as a label for the package of the present invention has high mechanical strength in the width direction perpendicular to the main shrinkage direction, which is highly shrinkable in the longitudinal direction, which is the main shrinkage direction. The produced roll-shaped film does not cause winding tightness, and the film roll has good openability so that wrinkles can hardly enter. Therefore, the heat-shrinkable polyester film can be suitably used as a label for a container such as a bottle, and can be attached to a container such as a bottle very efficiently within a short time. When it is later heat-shrinked, it can produce a good finish with very little shrinkage due to heat shrinkage. In addition, the attached label will exhibit very good openability. Therefore, the package of the present invention has good tearing of the coated label, and when the perforated line is provided in the direction perpendicular to the main shrinkage direction with a suitable force, the coated label is perforated. I can tear it cleanly along my eyes.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] The package of the present invention is formed by covering at least a part of the outer periphery with a label based on a heat-shrinkable polyester film, and subjecting the package to heat shrinkage. Examples include plastic bottles for beverages, various bottles, cans, plastic containers such as confectionery and lunch boxes, and paper boxes (hereinafter collectively referred to as packaging objects). In general, when a label based on a heat-shrinkable polyester film is coated on the packaging object by heat-shrinking, the label is heat-shrinked by about 2 to 15% and packaged. Adhere to the body. Note that the label to be coated on the packaging object may be printed or may have a perforation in a direction perpendicular to the main shrinkage direction of the label. Also good.

[0019] Also, when the label is coated on the packaging object, an annular body is formed in advance so that the main shrinkage direction is the circumferential direction, and the annular body is covered with the packaging object and thermally contracted. The force that can be adopted in the method When forming an annular body like this, in addition to the method of bonding the heat-shrinkable film using various adhesives, the heat-shrinkable film using a high-temperature heating element It is also possible to use a method of fusing (melting sealing method) or the like. Heat When fusing and sealing shrinkable films, use a predetermined automatic bag making machine (for example, Kyoei Printing Machinery Materials Co., Ltd.—RP500) to set the temperature and angle of the fusing blade to the specified conditions (for example, A method of forming an annular body or a bag at a predetermined speed (for example, 100 pieces / min) after adjusting to a temperature = 240 ° C. and a blade angle = 70 ° can be employed. In addition, when a label is to be covered on a packaged object, the label is wound around the packaged object by fusing and sealing the overlapped part, and then the heat shrinks after the label is placed around the packaged object. It is also possible to adopt the method of making them.

[0020] On the other hand, as the heat-shrinkable film for forming a label, various plastics such as a heat-shrinkable polyester film, a heat-shrinkable polystyrene film, a heat-shrinkable polyolefin film, and a heat-shrinkable polyvinyl chloride film are used. The heat shrinkable film can be listed as S. Among them, the use of heat-shrinkable polyester film increases the heat resistance of the label and makes the label excellent in solvent resistance. This is preferable because it can be easily incinerated. Therefore, in the following explanation, the explanation will focus on the heat-shrinkable polyester film.

[0021] Further, the package of the present invention has an Elmendorf tear load in a direction orthogonal to a main shrinkage direction and an Elmendorf tear load in a main shrinkage direction of a coated label (film substrate excluding a printing layer), The Elmendorf ratio measured by the following method must be 0.5 or more and 2.0 or less.

[0022] [Measurement method of Elmendorf ratio]

In accordance with JIS-K-7128, after cutting the label into a rectangular shape with a long main shrinkage direction, a test piece was prepared by cutting from the edge in the center of the longitudinal direction. , Shimadzu Corp. Autograph) and gripping both ends of the test piece, and performing a tensile test at a specified tensile speed, the Elmendorf tear load in the direction perpendicular to the main shrinkage direction of the label (Measured as Elmendorf tear load of the film base excluding the printed layer of the label) is measured. In addition, a test piece is prepared by cutting the label into a rectangular shape that is long in the direction perpendicular to the main shrinkage direction, and then making a cut from the edge in the center of the longitudinal direction. The Elmendorf tearing load in the main shrinkage direction of the label Measure the weight (converted as the Elmendorf tear load of the film base excluding the printed layer of the label). After that, the Elmendorf ratio is calculated using Equation 6 below.

Elmendorf ratio = Elmendorf bow in the direction perpendicular to the main contraction direction I crack load ÷ Elmendorf tear load in the main contraction direction · Equation 6

[0023] When the Elmendorf ratio of the label is less than 0.5, it is not preferable that there is a perforation in a direction perpendicular to the main contraction direction, because it is difficult to tear straight along the perforation. On the other hand, if the Elmendorf ratio of the label exceeds 2.0, it is not preferable because it is easy to tear at a position shifted from the perforation. The lower limit value of the Elmendorf ratio of the label is preferably 0.6 or more, more preferably 0.7 or more, and particularly preferably 0.8 or more. Further, the upper limit of the Elmendorf ratio of the film substrate excluding the printed layer of the label is preferably 1.8 or less, more preferably 1.6 or less, and particularly preferably 1.5 or less. .

[0024] Further, the package of the present invention, when the tensile fracture strength in the direction orthogonal to the main shrinkage direction of the coated label (film substrate excluding the printing layer) is measured by the following method, The tensile fracture strength must be lOOMPa or more and 300MPa or less.

[0025] [Measurement method of tensile fracture strength]

The label is sampled to a predetermined size according to JIS-K-7127 to obtain a test piece, and both ends of the test piece (main shrinkage direction) using a universal tensile tester (for example, Autograph manufactured by Shimadzu Corporation) And tensile test at a tensile speed of 200 mm / min, and the stress value at break (converted as the stress value of the film substrate excluding the printed layer of the label) calculate.

[0026] When the tensile fracture strength in the direction perpendicular to the main shrinkage direction of the label is less than lOOMPa, when the label is torn along the perforation in the direction perpendicular to the main shrinkage direction, On the contrary, if the tensile fracture strength in the direction perpendicular to the main shrinkage direction of the label exceeds 300 MPa, the initial cut W will be poor when tearing. It is not preferable. The lower limit of the tensile fracture strength is preferably 120 MPa or more, more preferably 140 MPa or more, and even more preferably 160 MPa or more. Further, the upper limit value of the tensile fracture strength is preferably 280 MPa or less, more preferably 260 MPa or less, and particularly preferably 240 MPa or less. [0027] The package of the present invention preferably has a refractive index of 1.570 or more and 1.600 or less in the direction orthogonal to the main shrinkage direction of the coated label. If the refractive index in the direction perpendicular to the main shrinkage direction exceeds 1.600, the solvent adhesion deteriorates, which is not preferable. On the other hand, if it is less than 1.570, the cutting property is deteriorated, which is not preferable. The upper limit of the refractive index in the direction perpendicular to the main contraction direction is preferably 1.595 or less, more preferably 1.590 or less. The lower limit of the refractive index in the direction orthogonal to the main shrinkage direction is preferably 1.573 or more, and more preferably 1.575 or more.

[0028] In the package of the present invention, the perpendicular tear strength in the direction perpendicular to the main shrinkage direction per unit thickness of the coated label (film substrate excluding the printing layer) was measured by the following method. In this case, the right-angle tear strength must be 100N / mm or more and 300N / mm or less.

[0029] [Measurement method of right-angle tear strength]

The label is sampled as a test piece of a predetermined size according to JIS-K-7128. After that, grip both ends of the test piece with a universal tensile tester (for example, Autograph manufactured by Shimadzu Corporation), and in a direction perpendicular to the main shrinkage direction of the label at a pulling speed of 200 mm / min. Measure the strength at tensile failure. Then, calculate the right-angle tear strength per unit thickness using Equation 2 below.

Right angle tear strength = Strength at tensile failure ÷ Thickness · Equation 2

[0030] A right-angled bow in the direction perpendicular to the main shrinkage direction of the label I If the crack strength is less than 1 OON / mm, there is a possibility that it may be easily broken by an impact such as a drop during transportation. On the other hand, if the right-angle tear strength in the direction perpendicular to the main shrinkage direction of the label exceeds 300 N / mm, it is not preferable because the cutting property (easy to tear) at the initial stage of tearing becomes poor. The lower limit of the right angle tear strength is preferably 120 N / mm or more, more preferably 140 N / mm or more, and even more preferably 160 N / mm or more. Further, the upper limit of the right-angled tear strength is preferably 280 N / mm or less, more preferably 260 N / mm or less, and more preferably 240 N / mm or less.

[0031] The dicarboxylic acid component constituting the polyester used in the present invention includes terephthalol. Examples thereof include aromatic dicarboxylic acids such as acid, isophthalic acid, naphthalenedicarboxylic acid and orthophthalic acid, aliphatic dicarboxylic acids such as adipic acid, azelaic acid, sebacic acid and decanedicarboxylic acid, and alicyclic dicarboxylic acids.

[0032] When an aliphatic dicarboxylic acid (for example, adipic acid, sebacic acid, decanedicarboxylic acid, etc.) is contained, the content is preferably less than 3 mol%. A heat-shrinkable polyester film obtained by using a polyester containing 3 mol% or more of these aliphatic dicarboxylic acids has insufficient film stiffness at high speed.

[0033] In addition, it is preferable not to contain a trivalent or higher polyvalent carboxylic acid (for example, trimellitic acid, pyromellitic acid and anhydrides thereof)! The heat-shrinkable polyester film obtained by using the polyester containing these polyvalent carboxylic acids achieves the necessary high shrinkage rate.

[0034] Examples of the diol component constituting the polyester used in the present invention include aliphatic diols such as ethylene glycol, 13 propanediol, 14 butanediol, neopentino glycol, hexanediol, Examples include alicyclic diols such as 4-cyclohexanedimethanol, and aromatic diols such as bisphenol A.

[0035] The polyester used in the heat-shrinkable polyester film used as the label of the package of the present invention is a cyclic diol such as 1,4-cyclohexanedimethanol or a diol having 3 to 6 carbon atoms ( For example, a polyester containing one or more of 13 propanediol, 14 butanediol, neopentyldaricol, hexanediol, etc.) and having a glass transition point (Tg) adjusted to 60 to 80 ° C Is preferred.

[0036] The polyester used for the heat-shrinkable polyester film has a total of 10 mol% or more of one or more monomer components that can be an amorphous component in 100 mol% of the polyhydric alcohol component in all the polyester resins. It is preferably 15 mol% or more, more preferably 17 mol% or more. Here, examples of monomers that can be an amorphous component include neopentyl glycol, 1,4-cyclohexanediol, and isophthalanolic acid.

[0037] In the polyester used for the heat-shrinkable polyester film, a diol having 8 or more carbon atoms (such as octanediol) or a polyhydric alcohol having 3 or more valences (for example, For example, trimethylolpropane, trimethylolethane, glycerin, diglycerin, etc.) are preferably not contained. A heat-shrinkable polyester film obtained by using a polyester containing these diols or polyhydric alcohols can achieve the necessary high shrinkage.

[0038] The polyester used for the heat-shrinkable polyester film preferably contains as little diethylene glycol, triethylene glycol, or polyethylene glycol as possible. In particular, although diethylene glycol is easily present because it is a by-product component during polyester polymerization, it is preferred that the polyester used in the present invention has a diethylene glycol content of less than 4 mol%! /.

[0039] A heat-shrinkable polyester-based film is a film length calculated by the following formula 1 from the length before and after shrinkage when treated for 10 seconds in 90 ° C warm water under no load. The direction of heat shrinkage (that is, hot water heat shrinkage at 90 ° C) must be 40% or more and 80% or less.

Heat shrinkage rate = {(length before shrinkage, length after shrinkage) / length before shrinkage} X 100 (%) · Equation 1 [0040] Longitudinal hot water thermal shrinkage at 90 ° C is 40% If the temperature is below, the shrinkage amount is small, and the thermal shrinkage of the label after heat shrinkage will occur. Therefore, the hot water heat shrinkage in the longitudinal direction at 90 ° C is 80% or more. If it is used as a label, it is not preferable because the shrinkage tends to occur at the time of heat shrinkage, or so-called "jumping" occurs. The lower limit value of the hot water thermal contraction rate in the longitudinal direction at 90 ° C is particularly preferably 45% or more, more preferably 50% or more, and more preferably 55% or more. Further, the upper limit value of the hot water heat shrinkage in the longitudinal direction at 90 ° C is particularly preferably 75% or less, preferably 70% or less, and more preferably 65% or less.

[0041] Further, the heat-shrinkable polyester film is a film thickness calculated by the above equation 1 from the length before and after shrinkage when treated in 90 ° C warm water for 10 seconds under no load. The hot water thermal contraction rate in the width direction must be 0% or more and 15% or less.

[0042] If the hot water thermal shrinkage in the width direction at 90 ° C is less than 0%, a good shrinkage appearance cannot be obtained when used as a bottle label. If the hot-water heat shrinkage in the width direction exceeds 15%, it can be used as a label! / It is not preferred because sometimes the shrinkage tends to be distorted. The lower limit value of the hot-water heat shrinkage in the width direction at 90 ° C. is particularly preferably 3% or more, more preferably 4% or more when 2% or more. Further, the upper limit value of the hot water thermal contraction rate in the width direction at 90 ° C is particularly preferably 13% or less, more preferably 11% or less, preferably 14% or less.

[0043] Further, the heat shrinkable polyester film may have a natural shrinkage ratio of 0.05% or more and 1.5% or less after aging for 700 hours or more in an atmosphere of 40 ° C and 65% RH. is necessary. The natural shrinkage rate can be calculated using the following equation 4.

Natural shrinkage rate = {(length before aging) / length before aging} X 100 (%) · Formula 4

[0044] When the natural shrinkage rate is 1.5% or less, when a product wound in a roll shape is stored, winding tightening occurs and the film roll is easily wrinkled, which is not preferable. The smaller the natural shrinkage rate, the better. However, from the viewpoint of measurement accuracy, 0.05% is considered to be the lower limit. Further, the natural shrinkage rate is preferably 1.3% or less, more preferably 1.1% or less, and particularly preferably 1.0% or less.

On the other hand, in the present invention, the maximum heat shrinkage stress force in the longitudinal direction of the film is preferably not less than MPa and not more than 25 MPa. Maximum heat shrinkage stress value in the longitudinal direction of the film 未満 If it is less than a, when the label is attached to a container such as a PET bottle and thermally contracted, the label is attached together with the cap when the PET bottle cap is opened. This is not preferable because it may cause a situation where the cap opens and deteriorates the opening of the cap. On the other hand, if the maximum heat shrinkage stress value in the longitudinal direction of the film exceeds 25 MPa, the sealed part may be removed or the appearance may deteriorate when the film is attached to a container such as a PET bottle as heat-condensed. (That is, the finishing force S deteriorates). The lower limit of the maximum heat contraction stress value in the longitudinal direction of the film is more preferably 6 MPa or more, particularly preferably 7 MPa or more. Further, the upper limit of the maximum heat shrinkage stress value in the longitudinal direction of the film is more preferably 23 MPa or less, and particularly preferably 21 MPa or less.

[0046] In addition, in the present invention, the fusing seal strength of the film is preferably 8 N / 15 mm or more. If the fusing seal strength of the film is less than 8N / 15mm, It is not preferable because the fusing seal part is removed when it is heat-shrinked after being attached to a container such as a PET bottle, or when the container after heat-shrinking is dropped, the fusing seal part is removed. It should be noted that the higher the fusing seal strength of the film, the higher the preferred breaking strength of the film. Further, the fusing seal strength of the film is more preferably 10 N / 15 mm or more, further preferably 12 N / 15 mm or more, and particularly preferably 14 N / 15 mm or more.

[0047] Further, the heat-shrinkable polyester film preferably has a solvent adhesive strength of 4 (N / 15mm) or more. If the solvent adhesive strength is less than 4 (N / l 5 mm), it is preferable because the label is easily peeled off from the solvent-adhered portion after heat shrinkage. The solvent adhesive strength is more preferably 4.5 (N / l 5 mm) or more, particularly preferably 5 (N / l 5 mm) or more.

[0048] In addition, the heat-shrinkable polyester film preferably has a thickness unevenness of 10% or less in the longitudinal direction. If the thickness unevenness in the longitudinal direction is more than 10%, it is not preferable because printed spots are likely to occur during printing at the time of label production or shrinkage spots after heat shrinkage are likely to occur. The longitudinal thickness unevenness is more preferably 8% or less, and more preferably 6% or less.

[0049] The heat shrinkage rate, the maximum heat shrinkage stress value, the solvent adhesive strength, and the thickness variation in the longitudinal direction of the film are combined with the preferred production method described later using the preferred film composition described above. Can be achieved.

[0050] Furthermore, it is preferable that the heat-shrinkable polyester film does not detect the endothermic curve peak during the melting point measurement in differential scanning calorimetry (DSC). By making the polyester constituting the film amorphous, the peak of the endothermic curve at the time of measuring the melting point becomes more difficult to express. By making it highly amorphous to the extent that the endothermic curve peak at the time of melting point measurement does not appear, the solvent adhesive strength is improved, and the heat shrinkage rate and the maximum heat shrinkage stress value are increased within the above-mentioned preferred range. It becomes easy to control.

[0051] The thickness of the heat-shrinkable polyester film is not particularly limited.

00〃m force << preferably, 20 ~; more preferably 100〃m force.

[0052] Further, the heat-shrinkable polyester film is obtained by using the above-described polyester raw material by an extruder. The film can be obtained by melt extrusion to form an unstretched film, and then subjecting the unstretched film to a two-wheel drive and heat treatment by the method described below.

[0053] When the raw material resin is melt-extruded, the polyester raw material is preferably dried using a dryer such as a hopper dryer or a pad dryer, or a vacuum dryer. After drying the polyester raw material in this way, it is melted at a temperature of 200 to 300 ° C and extruded into a film using an extruder. For force and squeeze extrusion, any existing method such as T-die method or tubular method can be used.

[0054] Then, it is possible to obtain an unstretched film by rapidly cooling the extruded sheet-like molten resin. As a method of rapidly cooling the molten resin, a method of obtaining a substantially unoriented resin sheet by casting the molten resin on a rotating drum from a die and rapidly solidifying it can be suitably employed.

[0055] Further, as will be described later, the obtained unstretched film was stretched in the width direction under predetermined conditions, and then heat-treated, and then stretched in the longitudinal direction under predetermined conditions, and then longitudinally stretched. By rapidly cooling the subsequent film, it becomes possible to obtain a heat-shrinkable polyester film used as a label for the package of the present invention. Hereinafter, the preferred biaxial stretching / heat treatment method for obtaining the heat-shrinkable polyester film used in the package of the present invention is different from the conventional biaxial stretching of the heat-shrinkable polyester film. This will be described in detail in consideration of the above.

[0056] Preferred shrinkable polyester film! /, Stretching 'heat treatment method'

A normal heat-shrinkable polyester film is produced by stretching an unstretched film in the direction in which it is desired to shrink. Although there has been a high demand for heat-shrinkable polyester films that shrink in the longitudinal direction from the past, production is not possible because a wide film cannot be produced by simply stretching an unstretched film in the longitudinal direction. In addition, the film cannot be produced with good thickness and unevenness. In addition, if a method of stretching in the longitudinal direction after previously stretching in the width direction is adopted, the amount of contraction in the longitudinal direction becomes insufficient, or the width direction shrinks unnecessarily. Further, as described above, Japanese Patent Application Laid-Open No. 8-244114 discloses a method of stretching an unstretched film in the order of length, width, and length under predetermined conditions in order to improve the mechanical properties in the longitudinal direction. Power S, the inventors' pilot According to a follow-up test on a sheet machine, such a method cannot provide a film having sufficient shrinkage in the longitudinal direction, which is the main shrinkage direction, and the produced film roll is likely to be crushed in the width direction. Turned out to be. In addition, increasing the draw ratio in the machine direction (the first draw ratio or the second draw ratio) in order to increase the shrinkability in the longitudinal direction will eventually increase the film when stretched in the longitudinal direction. It was also found that it was difficult to carry out continuous and stable production due to frequent fractures. In addition, the film obtained by the above-described test had a longitudinal crease on a film roll produced with a high natural shrinkage rate, and the unsealing property was also poor.

In order to finally increase the amount of contraction in the longitudinal direction, the present inventors perform biaxial stretching in the longitudinal direction and width direction as in JP-A-8-244114, and then stretch in the longitudinal direction. The method is disadvantageous and we thought that it would be advantageous to simply stretch in the width direction and then stretch in the longitudinal direction. In such a method of stretching in the longitudinal direction after stretching in the width direction (hereinafter, simply referred to as a transverse and longitudinal stretching method), the hot water temperature shrinkage rate, the natural shrinkage rate in the longitudinal direction of the film, depending on the conditions in each stretching step, We studied earnestly how the openability changes. As a result, it was found that the following measures were taken when the film was produced by the transverse and longitudinal stretching method, whereby the amount of shrinkage in the longitudinal direction was increased, and the film could be produced continuously and stably. In addition, if the following measures are taken, the film's natural shrinkage rate will be reduced, and it will be difficult for the film roll to be creased, and the perforation of the film will be dramatically improved. It has been found that there is a surprising side effect that it will be good. And the present inventors came to devise this invention based on those knowledge.

(1) Control of shrinkage stress after stretching in the width direction

(2) Interruption of heating between stretching in the width direction and intermediate heat treatment

(3) Trimming of film edge before stretching in the longitudinal direction

(4) Control of film cooling rate after longitudinal stretching

Hereinafter, each of the above-described means will be described sequentially.

[0058] (1) Control of shrinkage stress after stretching in the width direction

The film used as a label of the package of the present invention is produced by the transverse and longitudinal stretching method. In this case, after the unstretched film is stretched in the width direction, it is heat-treated at a temperature of 100 ° C or higher and lower than 170 ° C for a time of 1.0 second or more and 10.0 seconds or less (hereinafter referred to as intermediate heat treatment). is required. By carrying out force and intermediate heat treatment, it is possible to obtain a film having good cutting properties in the direction perpendicular to the main shrinkage direction and no shrinkage spots when used as a label. The reason why it is possible to obtain a film with good cutability and no shrinkage spots by performing a specific intermediate heat treatment after transverse stretching is not clear, but by performing a specific intermediate heat treatment, We believe that it is possible to reduce the shrinkage stress in the width direction while leaving some molecular orientation in the width direction. The lower limit of the temperature of the heat treatment is preferably 110 ° C or higher, more preferably 115 ° C or higher. The upper limit of the heat treatment temperature is preferably 165 ° C. or less, more preferably 160 ° C. or less. On the other hand, the heat treatment time needs to be appropriately adjusted according to the raw material composition within a range of 1.0 second to 10.0 seconds.

[0059] The unstretched film is stretched in the width direction at a temperature of Tg + 5 ° C or higher and Tg + 40 ° C or lower with a clip held at both ends in the width direction in the tenter. It is necessary to make the magnification between 2 times and 6.0 times. If the stretching temperature is lower than Tg + 5 ° C, breakage is likely to occur during stretching. On the other hand, if it exceeds Tg + 40 ° C, thickness unevenness in the width direction is deteriorated. The lower limit of the transverse stretching temperature is preferably Tg + 10 ° C. or more, more preferably Tg + 15 ° C. or more. Further, the upper limit of the transverse stretching temperature is preferably Tg + 35 ° C. or less, more preferably Tg + 30 ° C. or less. On the other hand, if the draw ratio in the width direction is less than 2.5 times, if the productivity is poor, the force and the thickness unevenness in the width direction are worsened. In addition, it is not preferable because a large amount of energy, a large force, and a large device are required for mitigation, and productivity is deteriorated. The lower limit of the transverse stretching ratio is preferably 3.0 times or more, more preferably 3.5 times or more. In addition, the upper limit of the transverse stretching ratio is preferably 5.5 times or less, more preferably 5.0 times or less.

[0060] (2) Interruption of heating between stretching in the width direction and intermediate heat treatment

In the production of the film used as the label of the package of the present invention by the transverse and longitudinal stretching method, it is necessary to perform an intermediate heat treatment after the transverse stretching as described above. And intermediate heat treatment, it is necessary to pass through an intermediate zone where no aggressive heating operation is performed for a time of 0.5 seconds or more and 3.0 seconds or less. That is, when considering the production cost, it is preferable to perform transverse stretching and intermediate heat treatment in the same tenter. 1S In the production of a film used in the present invention, force, transverse stretching zone in the tenter and heat treatment are used. It is preferable to provide an intermediate zone between the zones. In addition, when a strip-like piece of paper is hung in the middle zone! /, Let it pass through the film! / ,! Thus, it is preferable to block hot air from the stretching zone and the heat treatment zone. In the production of the film used in the present invention, it is preferable that the laterally stretched film is led to the intermediate zone to be applied and allowed to pass through the intermediate zone over a predetermined time. If the time for passing through the intermediate zone is less than 0.5 seconds, the hot air in the transverse stretching zone flows into the heat setting zone due to the accompanying flow of the passing film, making it difficult to control the temperature of the intermediate heat treatment in the heat setting zone. I don't like it. On the other hand, the time required to pass through the intermediate zone is sufficient if it is 3.0 seconds, and setting it longer than that is not preferable because it wastes equipment. Note that the lower limit of the time for passing through the intermediate zone is preferably 0.7 seconds or more, more preferably 0.9 seconds or more. The upper limit of the time for passing through the intermediate zone is preferably 2.5 seconds or less, and more preferably 2.0 seconds or less.

(3) Trimming of film edge before stretching in the longitudinal direction

In the production of the film used as the label of the package of the present invention by the transverse and longitudinal stretching method, the film subjected to the intermediate heat treatment is not sufficiently stretched at the edge of the film before stretching in the longitudinal direction. It is preferable to trim the thick part (mainly the clip gripping part during transverse stretching). More specifically, the thickness of the central part located at the edges of the left and right edges of the film is about 1.;! It is preferable to cut the thick portion and remove the thick portion, while stretching only the remaining portion in the longitudinal direction. In addition, when trimming the film edge as described above, it is preferable to cool the film so that the surface temperature of the film before trimming is 50 ° C. or less. By cooling the film in this way, it is possible to perform trimming without disturbing the cut surface. Also, trimming of the film edge can be done using a normal cutter. When a round blade with a circumferential edge is used, the edge of the edge does not become dull locally, and the film edge can continue to be cut sharply over a long period of time. Since the situation which induces the fracture | rupture in does not arise, it is preferable.

[0062] By trimming the end of the film before stretching in the longitudinal direction, it was possible to stretch the heat-fixed film uniformly in the longitudinal direction, and it was stable for the first time without breaking. Continuous production of the film becomes possible. In addition, it is possible to obtain a film having a large shrinkage in the longitudinal direction (main shrinkage direction). Furthermore, since the film can be uniformly stretched in the longitudinal direction, a film having a small thickness unevenness in the longitudinal direction can be obtained. In addition, by trimming the edge of the film, bowing during stretching in the longitudinal direction can be avoided, and a film with a small difference in physical properties between the left and right can be obtained.

[0063] (4) Control of cooling rate of film after longitudinal stretching

In the production of the film used as the label of the package of the present invention by the transverse and longitudinal stretching method, the intermediate heat treatment is performed after the transverse stretching as described above, and then the film is stretched in the longitudinal direction, and then 30 ° C / second or more and 70 ° The film is preferably cooled at a cooling rate of C / sec or less until the surface temperature is 45 ° C or higher and 75 ° C or lower. Thus, the natural shrinkage rate can be reduced only by cooling the film at an appropriate speed. If the cooling rate is lower than 30 ° C / sec or the surface temperature after cooling is higher than 75 ° C, a low natural shrinkage rate cannot be obtained. On the other hand, it is preferable that the cooling rate is so rapid that the cooling rate exceeds 70 ° C / second, since the degree of shrinkage in the width direction of the film (so-called neck-in) increases and the film surface is easily damaged. Absent.

[0064] It should be noted that only one of the above-mentioned means (1) to (4) is the heat shrinkability in the longitudinal direction of the film, the perforation opening property, the low natural shrinkage rate, and the stable film forming property. By using a combination of the means (1) to (4) that do not contribute effectively to the heat, it is very efficient, heat shrinkability in the longitudinal direction, perforation opening, low natural shrinkage, stable It is thought that film-forming properties can be expressed.

Example

[0065] Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited to the embodiment and can be appropriately changed without departing from the spirit of the present invention. Tables 1 and 2 show the properties, compositions, examples, and film production conditions (stretching and heat treatment conditions, etc.) of the raw materials used in the examples and comparative examples, respectively.

[table 1]

[Table 2]

[0068] The film evaluation method is as follows.

[0069] Shrinkage rate (hot water thermal shrinkage rate)]

Cut the film into a square of lOcm x 10cm, heat-shrink it in warm water at the specified temperature ± 0.5 ° C for 10 seconds under no load condition, and then measure the vertical and horizontal dimensions of the film. Measured, and the thermal shrinkage rate was calculated according to the above formula 1. The direction in which the heat shrinkage rate is large was defined as the main shrinkage direction. [0070] [Tg (Glass transition point)]

Using a differential scanning calorimeter (model: DSC220) manufactured by Seiko Denshi Kogyo Co., Ltd., it was obtained by heating 5mg of unstretched film from 40 ° C to 120 ° C at a heating rate of 10 ° C / min. Obtained from the endothermic curve. A tangent line was drawn before and after the inflection point of the endothermic curve, and the intersection was defined as Tg (glass transition point).

[0071] [Tm (melting point)]

Using a differential scanning calorimeter (model: DSC220) manufactured by Seiko Denshi Kogyo Co., Ltd., the temperature at the peak of the endothermic curve when 5 mg of unstretched film was sampled and heated from room temperature at a heating rate of 10 ° C / min. I asked more.

[0072] [Thickness unevenness in the main contraction direction]

The film was sampled into a long roll of 30 m length x 40 mm width and measured at a speed of 5 (m / min) using a continuous contact thickness gauge manufactured by Micron Measuring Instruments Co., Ltd. In the above-described sampling of the roll-shaped film sample, the length direction of the film sample was set as the main shrinkage direction of the film. The maximum thickness at the time of measurement was Tmax., The minimum thickness was Tmin., And the average thickness was Tave.

Thickness unevenness = {(1¾ &. 1¾.) / Ding & 6.} 100 (%) · Formula 5

[0073] [Solvent adhesive strength]

The stretched film was sealed by applying 1,3 dioxolan and pasting the two together. After that, the seal part is cut to a width of 15mm in the direction perpendicular to the main shrinkage direction of the film (hereinafter referred to as the orthogonal direction), and then set in the universal tension tester STM-50 manufactured by Baldwin Co., Ltd. A 180 ° peel test was performed at 200 mm / min. And the tensile strength at that time was made into solvent adhesive strength.

[0074] [Fusing seal strength]

Using an automatic bag making machine (model: RP500) manufactured by Kyoei Printing Machinery Materials Co., Ltd., a cutting blade with a blade angle of 70 degrees was heated to 240 ° C at a heating bag making speed of 100 bags / min. After that, the fusing seal part of the bag-made product is cut into a strip with a width of 15 mm to prepare a sample piece, and using Tensilon (model: STM-T 50BP) manufactured by Toyo Baldwin, the distance between chucks is 50 mm and the tension The peel strength was measured by conducting a tensile test at a speed of 200 mm / min. And The average value of the peel strengths obtained for 10 sample pieces was taken as the fusing seal strength.

[0075] [Maximum heat shrinkage stress value]

The stretched film was cut into a size of main shrinkage direction X direction perpendicular to the main shrinkage direction = 200 mm × 15 mm. After that, Universal Tensile Tester STM manufactured by Baldwin Co., Ltd.

After adjusting −50 to a temperature of 90 ° C, the cut film was set and the stress value was measured when held for 10 seconds.

[0076] [Haze]

Based on JIS-K-7136, it was measured using a haze meter (Nippon Denshoku Industries Co., Ltd., 300A). The measurement was performed twice and the average value was obtained.

[0077] [Refractive index]

Using an “Abbe Refractometer Model 4T” manufactured by ATAGO Co., Ltd., each sample film was left in an atmosphere of 23 ° C. and 65% RH for 2 hours or more, and measurement was performed.

[0078] [Natural contraction rate]

The resulting film was cut into a size of main shrinkage direction X orthogonal direction = 200 mm x 30 mm, and allowed to stand (aging) in an atmosphere of 40 ° C x 65% RH for 4 hours, and then the main shrinkage direction of the film (Examples; ! ~ 6 and comparative examples;! ~ 3, 5 were measured for shrinkage in the longitudinal direction, and comparative example 4 was in the width direction).

[0079] The method for evaluating the coated label is as follows.

[0080] [Measurement method of tensile fracture strength]

The label attached to the PET bottle is peeled off, and the label is tested in accordance with JIS-K-7127 in a rectangular shape with a length of 50mm perpendicular to the main shrinkage direction and a length of 20mm in the main shrinkage direction. Using a universal tensile tester (manufactured by Shimadzu Corp., Auto Draft), hold both ends (both ends in the longitudinal direction) of the test piece and perform a tensile test at a tensile speed of 200 mm / min. The stress value at break was calculated as the tensile fracture strength.

[0081] [Right-angle tear strength]

A test piece was prepared by peeling off the label attached to the PET bottle and sampling the label into the shape shown in Fig. 1 in accordance with JIS-K-7128. Is the perforation direction of the label). After a while Using a universal tensile tester (Autograph made by Shimadzu Corp.), hold both ends of the test piece and bow in a direction perpendicular to the main shrinkage direction of the label at a pulling speed of 200 mm / min. I measured the strength at the time of tensile fracture, and calculated the right-angled tear strength per unit thickness using Equation 2 above.

[0082] [Elmendorf ratio]

The label attached to the PET bottle is peeled off, and the label is cut to a size of 37.5 mm X 31.5 mm in the main shrinkage direction X in the direction perpendicular to the main shrinkage direction according to JIS-K-7128. A test piece was prepared by making a 10 mm slit (cut) perpendicular to the edge from the center of the edge along the shrinkage direction. Then, using a universal tensile tester (Autograph manufactured by Shimadzu Corporation), both ends of the prepared test piece are grasped and a tensile test is performed at a tension speed of 200 mm / min. The Elmendorf tear load in the orthogonal direction was measured. In addition, test pieces were produced by switching the direction perpendicular to the main shrinkage direction and the main shrinkage direction of the film, and the Elmendorf tear load in the direction perpendicular to the main shrinkage direction was measured. Then, the Elmendorf ratio was calculated using the above formula 6 from the obtained main contraction direction and the Elmendorf bow I crack load in the direction perpendicular to the main contraction direction.

[0083] [Refractive index]

The label attached to the PET bottle is peeled off, the printing on the surface of the label is removed with a solvent (ethyl acetate, methyl ethyl ketone, etc.), and the label is left in an atmosphere of 65% RH for 2 hours or more. Later, measurement was performed using an “Abbe refractometer 4T type” manufactured by Atago Co., Ltd. The refractive index was measured by the method described above.

[0084] [Opening rate when falling down]

Fill the plastic bottle with the label with 500 ml of water, leave the plastic bottle in the refrigerator adjusted to about 5 ° C for 8 hours or more, and then place the perforated part downward from the height of the lm. The percentage of the perforations that were torn down was calculated (n = 100).

[0085] [Shrink finish]

The finished condition of the label attached around the PET bottle was visually evaluated according to the following criteria. ◎: No wrinkles, jumps, or insufficient shrinkage occurred, and no color spots were observed. ○: No wrinkles, jumps, or insufficient shrinkage could be confirmed, but some color spots were observed. : Neither jumping up nor insufficient shrinkage has occurred, but spots on the neck are seen X: Wrinkles, jumping up, insufficient shrinkage occurred

[0086] [Label Adhesion]

Sensory evaluation was performed on the degree of label displacement when the attached label and PET bottle were lightly twisted. X if the label does not move, X if it slips through or the label and bottle are misaligned.

[0087] [Perforation opening]

Fill the plastic bottle with the label with 500 ml of water, refrigerate to 5 ° C, tear the perforation on the label of the bottle immediately after taking out from the refrigerator with your fingertips, tear it cleanly along the perforation in the vertical direction, The number of labels that could be removed from the bottle was counted, and the percentage (%) for all 50 samples was calculated.

[0088] Polyesters used in Examples and Comparative Examples are as follows.

[0089] Polyester 1: Ethylene glycol 70 mol ^_0/0, polyester consisting of neopentyl glycol 30 mol ^_0/0 and terephthalic acid (IV 0. 72dl / g)

Polyester 2: Polyethylene terephthalate (IV 0.775dl / g)

Polyester 3: terephthalic acid units as dicarboxylic acid component 82.5 mole ^_0/0, consists isophthalic acid unit 17.5 mole ^_0/0, consisting of ethylene glycol as the diol component.

[0090] [Example 1]

The above polyester 1 and polyester 2 were mixed at a weight ratio of 90:10 and charged into an extruder. Thereafter, the mixed resin is melted at 280 ° C, extruded from a T-die, wound around a rotating metal roll cooled to a surface temperature of 30 ° C, and rapidly cooled to form an unstretched film having a thickness of 360 m. Obtained. At this time, the take-up speed of the unstretched film (rotation speed of the metal roll) was about 20 m / min. The Tg of the unstretched film was 67 ° C. Thereafter, the unstretched film was led to a tenter (first tenter) in which a transverse stretching zone, an intermediate zone, and an intermediate heat treatment zone were continuously provided. In the tenter, The length of the intermediate zone located between the transverse stretching zone and the intermediate heat treatment zone is set to about 40 cm. In addition, in the intermediate zone, when a strip-shaped piece of paper is dropped without passing through the film, the hot air from the stretching zone and the hot air from the heat treatment zone are blown so that the piece of paper hangs almost completely in the vertical direction. Blocked.

[0091] Then, after preheating the unstretched film guided to the tenter until the film temperature reaches 90 ° C, the unstretched film is stretched 4 times at 75 ° C in the transverse direction in the transverse stretching zone, After passing (passing time = approximately 1.2 seconds), the film was led to an intermediate heat treatment zone and heat treated at a temperature of 130 ° C for 2.0 seconds to obtain a transversely uniaxially stretched film having a thickness of 90 m. . Then, using a pair of left and right trimming devices (constituted by a round blade with a circumferential cutting edge) provided at the rear of the tenter, the edge of the lateral uniaxially stretched film (center The portion of the film having a thickness of about 1 to 2 times the thickness of the film was cut, and the ends of the finolem located outside the cutting site were continuously removed.

[0092] Further, the film with the end trimmed as described above was guided to a longitudinal stretching machine in which a plurality of roll groups were continuously arranged, and preheated on the preheating roll until the film temperature reached 70 ° C. Later, the film was stretched 3 times between stretching rolls set at a surface temperature of 95 ° C. Thereafter, the longitudinally stretched film was forcibly cooled by a cooling roll set at a surface temperature of 25 ° C. The surface temperature of the film before cooling was about 70 ° C, and the surface temperature of the film after cooling was about 25 ° C. The time required for cooling from 70 ° C to 25 ° C was about 1.0 seconds, and the film cooling rate was 45 ° C / second.

[0093] Then, the cooled film is guided to a tenter (second tenter), heat-treated in an atmosphere of 95 ° C for 2.0 seconds in the second tenter, cooled, and both edges are cut. By removing, a biaxially stretched film of about 30 m was continuously formed over a predetermined length to obtain a film roll made of a heat-shrinkable polyester film.

[0094] <Production of package with label attached>

The film roll obtained as described above is slit to a width of about 200 mm, and is then rolled into a predetermined length to create a small slit roll. Label printing (three-color printing) was repeatedly performed using the grass “gold” white ink of Co., Ltd. In addition, for each label printing, the longitudinal direction of the film roll and In the orthogonal direction, two perforations (a perforation in which circles of about 1 mm diameter are continuous at intervals of about 4 mm) across the entire width of the film were formed in parallel at intervals of about 22 mm. Then, one end of the roll-shaped film on which printing for labeling was applied was applied to a part of the outer periphery of a 500 ml PET bottle (month diameter 62 mm, minimum neck diameter 25 mm). The roll film was pulled out by a predetermined length and wound around the outer periphery of the PET bottle. Thereafter, the outer periphery of the PET bottle was covered with a label by covering the outer periphery of the PET bottle by fusing and sealing with a fusing seal blade adjusted to about 240 ° C. Then, using Fuji Astec Inc's steam tunnel (model: SH-1500-U), the PET bottle covered with the label was allowed to pass under the conditions of a passage time of 2.5 seconds and a zone temperature of 80 ° C. Label attachment was completed by heat-shrinking the label around the outer periphery of the PET bottle, and the neck part was adjusted so that the 40 mm diameter part would be one end of the label. The characteristics of the heat-shrinkable film, label (before and after mounting), and package (the PET bottle with the label) obtained as described above were evaluated by the method described above. Shown in

[0095] [Example 2]

A heat-shrinkable film was continuously produced in the same manner as in Example 1 except that polyester 1 and polyester 2 were mixed at a weight ratio of 70:30 and charged into an extruder. Further, a label was produced by the same method as in Example 1, and the label was attached to the outer periphery of the PET bottle by the same method as in Example 1. Then, the characteristics of the obtained film, the label before and after mounting, and the package were evaluated by the same method as in Example 1. The evaluation results are shown in Tables 3 and 4.

[0096] [Example 3]

A heat-shrinkable film was continuously produced in the same manner as in Example 1 except that the transverse stretch ratio in the tenter (first tenter) was changed to 5.0 times. The biaxially stretched heat-shrinkable polyester film had a thickness of about 24 m. Further, a label was produced by the same method as in Example 1, and the label was attached to the outer periphery of the pet bottle by the same method as in Example 1. And the obtained film, the label before and after mounting, and the package The characteristics were evaluated in the same manner as in Example 1. The evaluation results are shown in Tables 3 and 4.

[0097] [Example 4]

A heat-shrinkable film was continuously produced in the same manner as in Example 1 except that the temperature of the intermediate heat treatment in the tenter (first tenter) was changed to 140 ° C. The biaxially stretched heat-shrinkable polyester film had a thickness of about 24 m. Further, a label was produced by the same method as in Example 1, and the label was attached to the outer periphery of the pet bottle by the same method as in Example 1. The characteristics of the obtained film, the label before and after mounting, and the package were evaluated by the same method as in Example 1. The evaluation results are shown in Tables 3 and 4.

[Example 5]

A heat-shrinkable film was continuously produced in the same manner as in Example 1 except that the temperature of the stretching roll in the longitudinal stretching machine was changed to 92 ° C and the stretching ratio in the longitudinal direction was changed to 5.0 times. . The biaxially stretched heat-shrinkable polyester film had a thickness of about 18 m. Further, a label was produced by the same method as in Example 1, and the label was attached to the outer periphery of the PET bottle by the same method as in Example 1. The characteristics of the obtained film, the label before and after mounting, and the package were evaluated by the same method as in Example 1. The evaluation results are shown in Tables 3 and 4.

[0099] [Example 6]

A heat-shrinkable film was continuously produced in the same manner as in Example 1 except that the temperature of the stretching roll in the longitudinal stretching machine was changed to 92 ° C and the stretching ratio in the longitudinal direction was changed to 7.0 times. . The biaxially stretched heat-shrinkable polyester film had a thickness of about 13 m. Further, a label was produced by the same method as in Example 1, and the label was attached to the outer periphery of the PET bottle by the same method as in Example 1. The characteristics of the obtained film, the label before and after mounting, and the package were evaluated by the same method as in Example 1. The evaluation results are shown in Tables 3 and 4.

[0100] [Comparative Example 1]

The above polyester 3 is put into an extruder, melted at 265 ° C, extruded from a T-die, wound around a rotating metal roll cooled to a surface temperature of 30 ° C, and rapidly cooled to give a thickness of 360 m. An unstretched film was obtained. The undrawn film take-off speed is Same as Example 1. After that, the unstretched film is led to a longitudinal stretching machine (first longitudinal stretching machine) in which a plurality of roll groups are continuously arranged, preheated on a preheating roll, and then set to a surface temperature of 88 ° C. The drawn rolls were stretched 2.7 times. Further, the film stretched in the longitudinal direction is led to a tenter (first tenter) in which a transverse stretching zone and a heat treatment zone are continuously provided, and the transverse stretching zone is 97 ° C at a stretching temperature of 97 ° C. After being stretched by 3.5 times, it was heat treated at 125 ° C in a heat treatment zone. Thereafter, the heat-treated film was led to a longitudinal stretching machine (second longitudinal stretching machine) in which a plurality of roll groups were continuously arranged, preheated on a preheating roll, and then set to a surface temperature of 98 ° C. It was stretched again 1.5 times between the stretching rolls. Furthermore, the film stretched again in the longitudinal direction is guided to a tenter (second tenter), heat-treated at 85 ° C, cooled, and both edges are cut and removed, so that about 35 111 biaxially stretched films are obtained. A film was continuously formed over the length to obtain a heat-shrinkable polyester film roll. The surface temperature of the film after the heat treatment and before cooling was about 75 ° C, and the film was cooled to about 25 ° C in about 2.0 seconds (cooling rate = 25 ° C / second). Further, a label was produced by the same method as in Example 1, and the label was attached to the outer periphery of the PET bottle by the same method as in Example 1. Then, the characteristics of the obtained film, the label before and after mounting, and the package were evaluated by the same method as in Example 1. The evaluation results are shown in Tables 3 and 4.

[0101] [Comparative Example 2]

A heat-shrinkable film was continuously produced in the same manner as in Example 1 except that the temperature of the intermediate heat treatment in the tenter (first tenter) was changed to 70 ° C. Further, a label was produced by the same method as in Example 1, and the label was attached to the outer periphery of the PET bottle by the same method as in Example 1. The characteristics of the obtained film, the label before and after mounting, and the package were evaluated by the same method as in Example 1. The evaluation results are shown in Tables 3 and 4.

[0102] [Comparative Example 3]

Guide the unstretched film to the tenter, preheat it until the film temperature reaches 90 ° C, then cool it by stretching 8.0 times in the transverse direction at a stretching temperature of 75 ° C, and cut and remove both edges Thus, a transversely uniaxially stretched film of about 45 Hm was continuously formed over a predetermined length to obtain a heat-shrinkable polyester film roll. Note that the film after cooling and before cooling The surface temperature was about 75 ° C, and it was cooled to about 35 ° C in about 2.0 seconds (cooling rate = 20 ° C / second). Further, a label was produced by the same method as in Example 1, and the label was attached to the outer periphery of the PET bottle by the same method as in Example 1. The characteristics of the obtained film, the label before and after mounting, and the package were evaluated by the same method as in Example 1. The evaluation results are shown in Tables 3 and 4. In the film of Comparative Example 3, the width direction is the main shrinkage direction, and the longitudinal direction is the direction orthogonal to the main shrinkage direction.

[0103] [Comparative Example 4]

A heat-shrinkable film was continuously produced in the same manner as in Comparative Example 1 except that the draw ratio at the time of longitudinal stretching again with the second longitudinal stretching machine was 3.0 times. Further, a label was produced by the same method as in Example 1, and the label was attached to the outer periphery of the pet bottle by the same method as in Example 1. The characteristics of the obtained film, the label before and after mounting, and the package were evaluated by the same method as in Example 1. The evaluation results are shown in Tables 3 and 4.

[0104] [Table 3]

[0105] [Table 4]

As is clear from Table 3, the films obtained in Example 16 were all not shrinkable in the width direction perpendicular to the main shrinkage direction, which is highly shrinkable in the longitudinal direction, which is the main shrinkage direction. It was always low. In addition, the films obtained in Example 16 all had high solvent adhesive strength, small thickness spots in the longitudinal direction, good label adhesion, and good shrink finish with no shrink spots. . In addition, the heat-shrinkable polyester film of Example 16 has a good perforation opening property, and has a film roll manufactured with a small natural shrinkage rate. Never occurred. In addition, the packaging body in which the label made of the heat-shrinkable polyester film obtained in each example is packaged has a good perforation-opening property of the label, and the label has a proper force along the perforation. It was possible to tear it cleanly.

[0107] On the other hand, the heat-shrinkable film obtained in Comparative Example 1 had an insufficient heat-shrinkage, poor label adhesion, and shrinkage spots. In addition, the heat-shrinkable film obtained in Comparative Example 2 had shrinkage spots due to poor label adhesion with a high heat shrinkage rate in the film width direction. In addition, the film obtained in Comparative Example 4 (the main shrinkage direction is the width direction) is produced with shrinkage spots having a large thermal shrinkage rate in the direction orthogonal to the main shrinkage direction and a large natural shrinkage rate. The film roll was wrinkled. In addition, the package that wraps the label made of heat-shrinkable polyester film obtained in each comparative example has poor perforation of the label, so that the label can be cleaned with an appropriate force along the perforation. The percentage of those that could not be torn was high.

Industrial applicability

[0108] Since the package of the present invention has excellent characteristics as described above, it can be suitably used for packaging use for various articles.

Explanation of symbols

[0109] Film.

Claims

The scope of the claims

[1] A package comprising a heat-shrinkable film-based label coated on at least a part of the outer periphery and heat-shrinked,

The Elmendorf ratio when the Elmendorf tear load in the direction orthogonal to the main shrinkage direction of the coated label and the Elmendorf tear load in the main shrinkage direction is measured is 0.5 or more and 2.0 or less. Packaging body.

[2] The package according to claim 1, wherein the tensile strength in the direction perpendicular to the main shrinkage direction of the coated label is not less than lOOMPa and not more than 300 MPa.

[3] The package according to claim 1 or 2, wherein a refractive index in a direction orthogonal to a main shrinkage direction of the coated label is 1.570 or more and 1.600 or less.

[4] The straight tear strength in the direction perpendicular to the main shrinkage direction per unit thickness of the coated label is 100 N / mm or more and 300 N / mm or less, according to claims 1 to 3, Package according to any one of the above.

[5] The package according to any one of [1] to [4], wherein a perforation or a pair of notches is provided along a direction perpendicular to the main shrinkage direction of the coated label.

[6] 2.5 times or more 6.0 times or less in the width direction at a temperature of Tg + 5 ° C or more and Tg + 40 ° C or less with the unstretched film held in the tenter by the clip at both ends in the width direction After stretching at a magnification of, passing through an intermediate zone where no aggressive heating operation is performed, heat treatment is performed at a temperature of 100 ° C to 170 ° C for 1.0 second to 10.0 seconds. After that, after cooling the film until the film surface temperature reaches 30 ° C or more and 70 ° C or less, and by cutting and removing the clip gripping portions at both edges in the width direction of the film, Tg + 5 ° C or more Tg + Stretch in the longitudinal direction at a temperature of 80 ° C or less 2.0 times or more and 5. 5 times or less, and then the film surface temperature at a cooling rate of 30 ° C / second or more and 70 ° C / second or less. The heat-shrinkable film before being formed into a label is manufactured by cooling until the temperature reaches 45 ° C or higher and 75 ° C or lower. That claim;! A ~ 5 / packaging body according to either shift.

[7] The package according to any one of [6] to [6], wherein the heat-shrinkable film is a heat-shrinkable polyester film.