JP2007262365A - Heat shrinkable polyester-based film roll and heat shrinkable label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat shrinkable polyester-based film roll having processing suitability as a beverage container label and solving problems due to insufficient slipperiness and to provide a method for producing the film roll. <P>SOLUTION: The film roll is obtained as follows. The heat shrinkage percentage in the maximum heat shrinkage direction is ≥20% when a plurality of samples cut out of a film into a square form of 10×10 cm are dipped in hot water at 85°C for 10 s, pulled up, then dipped in water at 25°C for 10 s and pulled up. The coefficient of dynamic friction (μd) between mutual faces of the film samples cut out from a long film according to prescribed requirements is ≤0.27 for all the samples. All the coefficients of dynamic friction (μd) for at least mutual one film surface are ≤0.30 after the film is dipped in hot water at 80°C for 20 s while thermally shrinking the film in the main shrinkage direction by 10%, pulled up and then naturally dried in an atmosphere at 23°C and 65% relative humidity for 24 h. The μd of all the samples is kept within the range of the average value±0.06. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a film roll formed by winding a heat-shrinkable polyester film suitable for label use, and more specifically, a heat-shrinkable polyester having a good outer surface slipperiness when used as a label for a beverage bottle. The present invention relates to a film roll formed by winding a system slippery film.

In recent years, for the purpose of packaging to improve the appearance of packaging, packaging to avoid direct impact of contents, label packaging that protects glass bottles or plastic bottles and displays products, etc.
A heat-shrinkable plastic film having a property of shrinking by heating is widely used. Plastic materials used for these purposes include stretched films such as polyvinyl chloride films, polystyrene films, and polyester films. Labels are used in various containers such as polyethylene terephthalate (PET) containers, polyethylene containers, and glass containers. And used for the purpose of cap seals or integrated packaging.

  In order to produce labels and the like, the following methods are usually employed. That is, the raw polymer is continuously melt extruded to produce an unstretched film. Next, stretching is performed to obtain a film roll. While feeding out the film from this film roll, it is slit to a desired width and wound into a roll again. Subsequently, character information such as various product names and designs are printed. After the printing is finished, the tube is manufactured by overlapping and joining the left and right ends of the film by means such as solvent bonding (tubing process). The slit process and the printing process may be reversed in order. If the obtained tube is cut into a suitable length, it becomes a cylindrical label, and a bag can be manufactured by joining one open end of this cylindrical label.

  And the inside of the shrink tunnel (steam tunnel) of the type that covers the label or bag etc. on the container and blows and heat shrinks by steam, and the shrink tunnel (hot air tunnel) of the type that blows hot air and heat shrinks, A final product (labeled container) is obtained by passing it on a belt conveyor or the like, and heat-shrinking a label, a bag, or the like so as to be in close contact with the container.

  However, the polyvinyl chloride film has excellent shrinkage characteristics, but has low heat resistance, and also has problems such as generation of hydrogen chloride gas during incineration and causing dioxins. Further, when a heat-shrinkable vinyl chloride resin film is used as a shrinkable label for a PET container or the like, there is a problem that the label and the container must be separated when the container is recycled.

On the other hand, a polystyrene film can be evaluated for its good finished appearance after shrinkage, but it is poor in solvent resistance, so an ink with a special composition must be used for printing. In addition, polystyrene resins need to be incinerated at a high temperature and have a problem that a large amount of black smoke and off-flavor are generated during incineration.
Polyester films without these problems are highly expected as shrink labels to replace polyvinyl chloride films and polystyrene films, and the amount of use tends to increase as the amount of PET container used increases.

However, further improvements in the properties of conventional heat-shrinkable polyester films and film rolls have been required (see, for example, Patent Document 1). That is, the shrinkable label is used in a state where the outer surface of the beverage container containing the PET container is coated. If the slipping property of the label is insufficient, the merchandise may be routed when the merchandise is conveyed inside the vending machine. There is a problem that the product is stuck inside and does not reach the outlet, or the products adhere to each other on the outer surface of the film and are discharged multiple times. It was from.
JP 2003-170494 A

  In the present invention, a heat-shrinkable label, a bag, etc. are manufactured from a roll wound with a long film, and these are put on a container and thermally contracted to provide a labeled container product. An object of the present invention is to provide a heat-shrinkable polyester film roll that can solve a number of problems in the process and reduce the occurrence of defective products, and a method for producing the same.

  The inventor of the present invention is a film roll formed by winding a heat-shrinkable polyester film, and the heat-shrinkable polyester film has a gist where the following requirements (1) and (2) are satisfied.

(1) When the winding start end of the film in the steady region where the film properties are stable in the length direction of the film is the first end, and the end on the winding end is the second end, The first sample cutout portion is provided within 2 m inside the two end portions, and the final cutout portion is provided within 2 m inside the first end portion, and the sample cutout portion is provided approximately every 100 m from the first sample cutout portion. Each sample cut into a square shape of 10 cm × 10 cm was dipped in hot water at 85 ° C. for 10 seconds, then dipped in water at 25 ° C. for 10 seconds, and then heat shrinkage in the maximum heat shrink direction. The rate is 20% or more for all samples.
(2) For each sample separately cut out from each sample cut-out section described in (1) above, the coefficient of dynamic friction (μd) between at least one surface of the cut out samples is 0.27 or less in all the samples. And after the film was immersed in hot water at 80 ° C. in the main shrinkage direction for 10 seconds while being thermally shrunk for 20 seconds, pulled up, and naturally dried in an atmosphere of 23 ° C. and relative humidity 65% for 24 hours, At least the dynamic friction coefficients between one side of the film are all 0.30 or less.

  Moreover, it is preferable that the film roll of this invention satisfies the following requirements (3) further.

(3) About each sample cut out separately from each sample cut-out part described in the above requirement (1), the cut-out film is immersed for 20 seconds in 80 ° C. warm water with 10% heat shrinkage in the main shrinkage direction. Then, when the average value of the dynamic friction coefficient between at least one side of the film after being naturally dried for 24 hours in an atmosphere of 23 ° C. and relative humidity of 65% is calculated, μd of all the samples is this average value. It is within the range of ± 0.06.

  In this invention, it is preferable that the easy-slip layer containing a silicone component is formed in the surface, and it is easy to obtain the film roll which satisfy | fills said each requirement. And in order to manufacture the film roll in which the slippery layer was formed, after apply | coating the coating liquid for slippery layers to the at least single side | surface of the melt-extruded unstretched polyester film or the non-fruit polyester-type film, this coating film is used. An in-line coating method including a step of biaxial stretching or uniaxial stretching is preferred.

  The heat-shrinkable film roll of the present invention has extremely low occurrence of defects due to the occurrence of clogging in a vending machine due to slippage in the film roll and fluctuations in surface characteristics, It has excellent processability and is very useful in industrial production.

  The film wound around the heat-shrinkable polyester film roll of the present invention must satisfy the following requirement (1).

  When the end of the film in the steady region where the film properties are stable in the length direction of the film is the first end, and the end on the end of the winding is the second end, the second end The first sample cutout portion is provided within 2 m of the first end portion, the final cutout portion is provided within 2 m inside the first end portion, and the sample cutout portion is provided about every 100 m from the first sample cutout portion. Each sample cut into a 10 cm × 10 cm square shape was immersed in hot water at 85 ° C. for 10 seconds and then pulled up, then immersed in water at 25 ° C. for 10 seconds, and the heat shrinkage rate in the maximum heat shrinkage direction was It is 20% or more for all samples.

  First, the meaning of the requirement (1) “steady region where film properties are stable in the length direction of the film” will be described. The “steady region where the film physical properties are stable in the length direction of the film” is a region where the film forming process and the stretching process are stably performed during film production, and the film physical properties are almost uniform. In the present invention, in a long film obtained when the film forming process and the stretching process are operated in a stable steady state, characteristics such as heat shrinkage characteristics and slipperiness are made more uniform than conventional levels. Is the technical idea. In actual operation, during film production, the composition of the film may vary depending on the raw material supply method and film formation conditions.In the present invention, the film obtained when the raw material supply amount and film formation conditions are unstable is used. It does not require uniformization. For this reason, it is assumed that the sampling for evaluating the characteristics requiring homogenization is performed only in the region where the film forming process and the stretching process are operated in a stable steady state, that is, the “steady region”.

  Therefore, for example, if the film is about 10 m from the beginning of winding of the roll when the steady operation is not performed, sampling is not performed from this portion, and the 10 m from the beginning of winding is sampled as the first end of the film.

  The number of the steady regions (steady operation regions) is normally one place per film roll (one place over the entire film roll). However, since there may be a plurality of locations depending on the manufacturing situation, sampling is performed only from the steady region in this case. The steady region can be evaluated, for example, by measuring the thermal shrinkage rate in the maximum shrinkage direction of the film by a method described later. That is, the region where the heat shrinkage rate is within a range of about 20% (the difference between the maximum value and the minimum value of the heat shrinkage rate of a plurality of samples is within about 20%) may be regarded as the steady region.

  The number of the steady regions (steady operation regions) is usually one place per film roll (one place over the entire film roll). However, depending on the manufacturing situation, there may be a plurality of locations. In this case, sampling is performed only from the steady region. The steady region can be evaluated, for example, by measuring the thermal shrinkage rate in the maximum shrinkage direction of the film by a method described later. That is, the region where the heat shrinkage rate is within a range of about 20% (the difference between the maximum value and the minimum value of the heat shrinkage rate of a plurality of samples is within about 20%) may be regarded as the steady region.

  Subsequently, a sampling method will be described. For the film wound on one roll, when the end of the film in the steady region on the winding start side is the first end and the end of the winding end is the second end, the second end The first sample cutout portion is provided within 2 m from the first end portion, and the final cutout portion is provided within 2 m inside the first end portion, and the sample cutout portion is provided approximately every 100 m from the first sample cutout portion. By providing, samples are selected at approximately equal intervals over the entire length of the steady region of the film. Note that “about every 100 m” means that the sample may be cut out at about 100 m ± 1 m.

  The sampling method will be described in more detail. For example, when a heat-shrinkable film having a total length of a steady region and a length of 498 m is wound around a roll, the first sample A is placed within 2 m from the end of winding (second end) of the film. cut out. The area to be cut out is appropriately selected according to the physical property value to be measured. Subsequently, the second sample B is cut out at a distance of about 100 m from where the first sample A was cut out. In the same manner, the third sample C is cut out at about 200 m, the fourth sample D is cut out at about 300 m, and the fifth sample E is cut out at about 400 m. Here, since the remainder becomes shorter than 100 m, the sixth (final) sample F cuts out any portion within 2 m from the start of winding (first end) of the film.

  The requirement (1) of the present invention is that the heat shrinkage rate in the maximum shrinkage direction of all the samples thus cut is 20% or more. If the heat shrinkage rate of the heat-shrinkable polyester film is less than 20%, the heat shrinkage force of the film is insufficient, and when the container is coated and shrunk, it does not adhere to the container, resulting in poor appearance. It is not preferable. A more preferable heat shrinkage rate is 40% or more, and further preferably 60% or more.

Here, the heat shrinkage rate in the maximum shrinkage direction means the heat shrinkage rate in the direction in which the sample is most contracted, and the maximum shrinkage direction is the length in the longitudinal direction or the transverse direction of the cut-out square sample. It is decided. Further, the heat shrinkage rate (%) was 25 ° C. ± 0.5 after a sample of 10 cm × 10 cm was immersed in warm water at 85 ° C. ± 0.5 ° C. for 10 seconds under a no-load condition and then heat shrunk. The film was measured in accordance with the following formula after measuring the length in the longitudinal and lateral directions after being immersed in water at 10 ° C. for 10 seconds under no load condition (hereinafter, the heat shrinkage in the maximum shrinkage direction measured under these conditions). The rate is simply abbreviated as “heat shrinkage rate”).
Heat shrinkage rate = 100 × (length before shrinkage−length after shrinkage) ÷ (length before shrinkage)

  Requirement (2) of the present invention is that when the friction coefficient μd between the same surfaces of each sample separately cut out from each sample cutout part in the above requirement (1) is measured, μd of all the samples is 0.27. In addition to the following, the film was immersed in hot water at 80 ° C. in the main shrinkage direction for 10 seconds while being thermally contracted for 20 seconds, then pulled up, and naturally dried in an atmosphere at 23 ° C. and relative humidity 65% for 24 hours. In other words, the dynamic friction coefficients of at least one side of the film are all 0.30 or less. The details of the sample sampling method are the same as those in the requirement (1).

  The long film satisfying the requirement (2) is excellent in slipperiness. This long film is excellent in slipperiness in the vending machine, particularly when used as a PET bottle label for beverages. For example, the contact area between the vending machine and adjacent products is large and clogged. Even if it is a square bottle which is easy to generate, clogging can be prevented. However, if the range of slipperiness is exceeded, the slipperiness becomes insufficient, and troubles such as clogging with vending machines occur.

  Requirement (3) is that for each sample separately cut from each sample cut-out part described in the above requirement (1), the cut film is thermally contracted in the main shrinkage direction in hot water at 80 ° C. by 10%. When the average value of the coefficient of dynamic friction μd between at least one side of the film was calculated after immersion for 20 seconds, lifting, and natural drying for 24 hours in an atmosphere of 23 ° C. and 65% relative humidity, μd of all samples was calculated. Is within the range of the average value ± 0.06. The details of the sample sampling method are the same as those in the requirement (1).

  Since the long film satisfying the requirement (3) has a high level of slidability in the length direction of the film, fluctuations in slidability of each label, bag, etc. are reduced. Since the variation of the slipperiness of each product after coating shrinkage is reduced, the trouble of clogging in the vending machine can be further reduced. At least after the cut film is immersed in warm water at 80 ° C. for 10 seconds while being thermally contracted in the main shrinkage direction for 20 seconds and then naturally dried in an atmosphere of 23 ° C. and relative humidity of 65% for 24 hours. The upper limit of the dynamic friction coefficient μd between one side of the film is more preferably 0.28, and the degree of variation is more preferably within an average value ± 0.05 of the dynamic friction coefficient.

  The dynamic friction coefficient μd between the same surfaces of the film is a value measured in an environment of 23 ° C. and 65% RH in accordance with JIS K 7125. This surface is a surface which becomes the outer side (surface opposite to the surface in contact with the container) when used as a label. When the slippery layer described later is formed, the dynamic friction coefficient μd between the slippery layers is measured.

  Next, constituent components of the polyester will be described. As the polyester-based resin, as a polyvalent carboxylic acid component, an aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, or one or more of these ester-forming derivatives is used and polycondensed with a polyhydric alcohol component (copolymerization) Polyester can be used

  Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid, and 5-sodium sulfoisophthalic acid. Examples of the aliphatic dicarboxylic acid include dimer acid, glutaric acid, adipic acid, sebacic acid, azelaic acid, oxalic acid, and succinic acid. Further, an oxycarboxylic acid such as p-oxybenzoic acid, and a polyvalent carboxylic acid such as trimellitic anhydride or pyromellitic anhydride may be used in combination as necessary. Among these, terephthalic acid, isophthalic acid, naphthalene-1,4- or -2,6-dicarboxylic acid is preferable. Examples of ester-forming derivatives include derivatives such as dialkyl esters, diaryl esters, and acid halides.

  Examples of the polyhydric alcohol component include ethylene glycol, diethylene glycol, dimer diol, propylene glycol, triethylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 3- Alkylene glycols such as methyl 1,5-pentanediol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1,9-nonanediol, 1,10-decanediol, Examples include alkylene oxide adducts of bisphenol compounds or derivatives thereof, trimethylolpropane, glycerin, pentaerythritol, polyoxytetramethylene glycol, and polyethylene glycol. In addition, ε-caprolactone can be used for the synthesis of polyester.

The main constituent unit of polyester is preferably an ethylene terephthalate unit in consideration of film tear resistance, strength, heat resistance, and the like. Specifically, in 100 mol% of the constituent unit of the polyester raw material, 50 mol of ethylene terephthalate unit is preferable. It is recommended to select at least%. Therefore, it is preferable that 50 mol% or more of the terephthalic acid component in 100 mol% of the dicarboxylic acid component and 50 mol% or more of the ethylene glycol component in 100 mol% of the polyhydric alcohol component. As for an ethylene terephthalate unit, 55 mol% or more is more preferable, and 60 mol% or more is further more preferable.

The secondary constituent unit other than the ethylene terephthalate unit is recommended to be 5 mol% or more, preferably 7 mol% or more, more preferably 9 mol% or more, in 100 mol% of the polyester raw material constituent unit. . It is because it becomes possible to ensure the solvent adhesiveness and heat shrinkability of the film by introducing the amorphous improvement component to the above extent.

As a secondary constituent unit other than the ethylene terephthalate unit, any unit other than the ethylene terephthalate unit such as a unit having propylene glycol as the polyhydric alcohol component and a unit having isophthalic acid as the polyvalent carboxylic acid component can be selected. . However, any one of a unit composed of 1,4-cyclohexanedimethanol and terephthalic acid, a unit composed of neopentyl glycol and terephthalic acid, and a unit composed of 1,4-butanediol and terephthalic acid are preferable. By including these secondary structural units in the polyester, good solvent adhesion is exhibited, heat shrinkability in a wide temperature range from low temperature to high temperature can be secured, and a beautiful shrink finish can be obtained. . In particular, 1,4-cyclohexanedimethanol and neopentyl glycol are excellent in the action of making the polyester amorphous, and can improve the heat shrinkability. Therefore, the most secondary unit is most preferably a unit composed of 1,4-cyclohexanedimethanol and terephthalic acid or a unit composed of neopentyl glycol and terephthalic acid. These units may be the same amount, and the maximum number of secondary component units may be two types.

In addition, the unit consisting of 1,4-butanediol and terephthalic acid is useful for the expression of heat shrinkability at low temperatures because the glass transition temperature of the film is lowered, but if it is too much, the film strength and the like may be lowered. Therefore, it is preferable to use the second secondary constituent unit rather than the most secondary secondary constituent unit.

In order to obtain a polyester film having the above preferred composition, for example,
(1) A combination of polyethylene terephthalate (PET) and polycyclohexylene dimethyl terephthalate,
(2) combining polyethylene terephthalate (PET) with a homopolyester composed of neopentyl glycol and terephthalic acid,
(3) combining polyethylene terephthalate (PET) and a homopolyester composed of polybutylene terephthalate (1,4-butanediol and terephthalic acid),
(4) combining the above four types of homopolyesters,
(5) Mixed diol component consisting of one or more diols selected from the group consisting of PET and neopentyl glycol, 1,4-cyclohexanedimethanol and 1,4-butanediol (ethylene glycol may be added if necessary) ) And copolyester consisting of terephthalic acid,
Etc. can be adopted.

That is, homopolyester or copolyester chips are produced, and the chips are mixed according to the above combination example. Even if homopolyesters having different compositions or a homopolyester and a copolyester are mixed, problems such as whitening of the film caused by poor compatibility do not occur. This is because the raw material polyester is heated considerably in the melt-kneading process in the extruder, so that a transesterification reaction occurs between the respective polyesters, and when extruded from the extruder, a mixture of copolymer polyesters having a similar composition is formed. It is because it will denature. This is confirmed from the fact that only one peak indicating the Tg of the film is observed.

Polyesters can be produced by melt polymerization according to a conventional method, but the so-called direct polymerization method in which an oligomer obtained by directly reacting a polyvalent carboxylic acid component and a polyhydric alcohol component is polycondensed, a dimethyl ester of a polyvalent carboxylic acid. Examples include a so-called transesterification method in which a polycondensation is performed after a transesterification reaction between the product and a polyhydric alcohol component, and any production method can be applied. Moreover, the polyester obtained by another polymerization method may be sufficient. The degree of polymerization of the polyester is preferably 0.5 to 1.3 dl / g in terms of intrinsic viscosity.

  In addition to polymerization catalysts such as antimony oxide, germanium oxide, and titanium compounds, polyester such as magnesium acetate, magnesium chloride and other Mg salts, calcium acetate, calcium chloride, etc. Ca salt, manganese acetate, manganese chloride and other Mn salts, zinc chloride, zinc acetate and other Zn salts, cobalt chloride, cobalt acetate and other Co salts as metal ions for each of the resulting polyesters at 300 ppm (mass basis, the same applies hereinafter) ) Hereinafter, phosphoric acid or phosphoric acid ester derivatives such as phosphoric acid trimethyl ester and phosphoric acid triethyl ester may be added in an amount of 200 ppm or less in terms of phosphorus (P).

  If the total amount of metal ions other than the above polymerization catalyst is 300 ppm with respect to the polyester and the amount of P exceeds 200 ppm, not only the coloration of the polymer will be significant, but also the heat resistance and hydrolysis resistance of the polymer will be significantly reduced. .

  At this time, the mass ratio (P / M) of the total P amount (P) and the total metal ion amount (M) is 0.4 to 1.0 in terms of heat resistance, hydrolysis resistance, and the like. Is preferred. When the mass ratio (P / M) is less than 0.4 or exceeds 1.0, the film may be colored or coarse particles may be mixed in the film, which is not preferable.

  The timing of adding the above metal ions, phosphoric acid and derivatives thereof is not particularly limited. In general, metal ions are added at the time of raw material charging, that is, before transesterification or esterification, and phosphoric acids are added before polycondensation reaction. It is preferable to do this.

  Further, if necessary, fine particles such as silica, titanium dioxide, kaolin, calcium carbonate may be added, and an antioxidant, an ultraviolet absorber, an antistatic agent, a coloring agent, an antibacterial agent, etc. may be added. it can.

  Next, a preferable method for producing a long film exhibiting characteristics such as uniform heat shrinkage behavior and slipperiness over the entire length will be described.

Generally, a heat-shrinkable polyester film is blended with two or more types / compositions of different polymers or a plurality of copolymerized monomer components as described above from the viewpoint of achieving both heat shrinkage properties and strength. For example, a method of introducing a secondary constituent unit in addition to the main constituent unit into the raw polymer to change the properties of the resulting film is employed. At this time, as a means for including one or more secondary constituent units in the film, a method of performing copolymerization and using this copolymer polymer alone and a method of blending different types of homopolymers or copolymer polymers There is.

  Also, when internally adding lubricants or antistatic agents, add them to any polymer (masterbatch), and adjust the amount of this polymer used to ensure the necessary amount of lubricant or antistatic agent. It is generally done.

In the system in which the copolymer is used alone, the amount of lubricant or the like hardly varies in the long film wound around the roll.
On the other hand, the blend method is widely used industrially because the film characteristics can be easily changed by simply changing the blend ratio, and it can be used for industrial production of various types of films. And in the case of such a polymer blend, since it has been found that fluctuations in the amount of lubricant, etc., and physical properties of the film wound on one roll are increased, each requirement specified in the present invention is satisfied. In order to obtain a film roll to be used, it is preferable to use the following method.

(1) Homogenization of chip shape In the blend method, normally, a plurality of raw material polymer chips having different compositions are blended in a hopper, a chip mixture is introduced into an extruder, and the polymer is melt-kneaded and extruded to form a film. To do. For example, when there are three types of polymers as raw materials, the respective polymer chips are supplied to three hoppers in a continuous or intermittent manner, and if necessary, via a buffer hopper, finally, immediately before the extruder or While mixing three types of polymer chips in a hopper immediately above (referred to as “final hopper” for convenience), raw material chips are quantitatively supplied to the extruder in accordance with the extrusion amount of the extruder to form a film. However, depending on the capacity or shape of the final hopper, the raw material segregation that the composition of the chips supplied from the final hopper to the extruder differs when the amount of chips in the final hopper is large and when the remaining amount is small. It was found that this phenomenon occurred. This problem is particularly noticeable when the shape or specific gravity of various polymer chips is different. If the material segregation phenomenon occurs and the composition of the polymer extruded from the extruder fluctuates accordingly, the heat shrink behavior of the heat shrinkable film to be produced will fluctuate. If only one of the chips contains a lubricant or an antistatic agent, the slipperiness of the long film varies as a result of segregation of raw materials.

  Therefore, when manufacturing a heat-shrinkable polyester film roll including a step of mixing and extruding a polymer having the largest amount of use and one or more other polymers having different compositions from this polymer, only the polymer composition is used. In addition, it is necessary to reduce fluctuations in the amount of lubricant, and as a means of reducing such fluctuations in the composition of the raw material composition, the raw material segregation phenomenon in the hopper can be achieved by combining the shapes of multiple types of polymer chips to be used. It is preferable to suppress.

  In order to produce a raw material chip for a polyester film, usually, after polymerization, a polymer in a molten state is taken out from the polymerization apparatus as a strand, immediately cooled with water, and then cut with a strand cutter. For this reason, the polyester chip usually has an elliptical column shape with an elliptical cross section. At this time, the average major axis (mm), the average minor axis (mm), and the average chip of the cross-sectional ellipse of the polymer chip of the most used amount are mixed as the polymer chip of the other polymer mixed with the most used polymer chip. It was found that the material segregation can be reduced by using those that are within ± 20% of the length (mm). It is more preferable to use those having an average value within a range of ± 15%.

  If there is a difference in the size of the chips, when the mixture of chips falls in the final hopper, small chips tend to fall first, so if the remaining amount of chips in the final hopper decreases, the ratio of large chips This increases the amount of raw material segregation. However, by using a chip within the above range, these raw material segregation can be reduced, and a long film having a uniform composition can be obtained.

  The raw material chips may be pre-mixed and then fed to the final hopper and the extruder via several intermediate (buffer) hoppers. When mixing multiple types of raw material chips, there is a method of mixing in a hopper using an apparatus that can continuously supply raw material chips, or a method of mixing in advance using a blender, etc. In the latter case, it is preferable to pay attention to the size of the raw material chips so that the raw material segregation does not occur when the mixture is discharged.

(2) Optimization of hopper shape An extruder is used to obtain a film, and optimization of the final hopper shape is also a preferable means for obtaining a long film having a uniform composition. That is, if the inclination angle of the funnel-shaped hopper is smaller than 60 °, only small chips will fall first and cause segregation of raw materials. By using a hopper with an inclination angle of 65 ° or more, a large chip can be easily dropped as well as a small chip, and the upper end of the contents (chip) descends in the hopper while maintaining a horizontal plane. Helps reduce raw material segregation. A more preferable inclination angle is 70 ° or more. The inclination angle of the hopper is an angle between the funnel-shaped hypotenuse and the horizontal line segment. A plurality of hoppers may be used upstream of the final hopper. In this case, the inclination angle is 65 ° or more, more preferably 70 ° or more in any hopper.

(3) Optimization of hopper capacity As a means for reducing raw material segregation in the hopper, optimizing the capacity of the hopper is also a preferable means. The proper capacity of the hopper is in the range of 15 to 120% by mass of the discharge amount per hour of the extruder. If the hopper has a capacity of about 15% by mass or more of the discharge amount, it is difficult to stably supply the raw material. If the hopper is too large, the raw material chip mixture remains in the hopper for a long time. The reason that the segregation of the chip may occur is the reason for setting the hopper capacity within the above range. The capacity of the hopper is more preferably in the range of 20 to 10% by mass of the discharge amount per hour of the extruder.

(4) Reduction of fine powder In order to obtain a long film having a uniform composition, it is also a preferable means to reduce the ratio of fine powder generated due to scraping of raw material chips to be used. Since the fine powder promotes the occurrence of raw material segregation, it is preferable to remove the fine powder generated in the process and reduce the ratio of the fine powder contained in the hopper. The ratio of the fine powder contained is preferably controlled within 1% by mass and more preferably within 0.5% by mass in 100% by mass of the raw material throughout all steps until the raw material chips enter the extruder. preferable. Specifically, the fine powder may be removed by manufacturing a chip with a strand cutter and then passing it through a sieve, or when passing a raw material chip by air, for example, through a cyclone air filter.

Since the composition of the film extruded from the extruder by the means (1) to (4) is uniform over the entire long film, the lubricant and antistatic agent added to the chip are also long. The amount is uniformly present throughout the film, and the requirements of the present invention can be satisfied.

  What can be used as an additive-type lubricant / antistatic agent is various compounds described later as those that can be used in a coating solution for forming a slippery layer. Particle types such as inorganic particles, organic salt particles, and crosslinked polymer particles are also effective for imparting slipperiness.

Examples of the inorganic particles include calcium carbonate, kaolin, talc, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, and riotium fluoride. Etc. In particular, in order to obtain a film having a lower haze while obtaining good handling properties, the inorganic particles are preferably aggregated silica particles formed by agglomerating primary particles. Examples of the organic salt particles include terephthalate such as calcium oxalate, calcium, barium, zinc, manganese, and magnesium.

Examples of the crosslinked polymer particles include homopolymers or copolymers of vinyl monomers such as divinylbenzene, styrene, acrylic acid or methacrylic acid. In addition, organic particles such as polytetrafluoroethylene, benzoguanamine resin, thermosetting urea resin, and thermosetting phenol resin may be used.

  Examples of the method for adding the lubricant include a method in which the lubricant is dispersed in the polymerization step of the polyester used as the film raw material, a method in which the polyester after polymerization is melted again, and the like. In addition, when trying to impart slipperiness to the film, there is a method of roughening the surface with the above-mentioned lubricant particles and reducing the contact area. However, if too much is added, the transparency of the film is lowered and the commercial value is impaired. Therefore, it is recommended that the lubricant particles be reduced or not used, the slippery layer described later be reduced or not used, and the slippery layer described later be formed to impart slipperiness to the film.

  In order to satisfy the requirements (2) and (3), it is preferable to form the slippery layer on at least one side of the film. In order to form an easy-sliding layer, the film coating method for forming the easy-sliding layer and the non-sliding method is the simplest. In order to prevent the lubricant from falling off and improve the solvent adhesiveness of the film, It is desirable to contain a binder resin.

  It should be noted that the use of a particulate lubricant component as a lubricant may interfere with the transparency of the film and may cause the particles to agglomerate. Preferred lubricants that do not cause such problems include paraffin wax, microwax, polypropylene wax, polyethylene wax, ethylene-acrylic wax, stearic acid, behenic acid, 12-hydroxystearic acid, stearic acid amide, oleic acid amide, Erucic acid amide, methylene bis stearic acid amide, ethylene bis stearic acid amide, ethylene bis oleic acid amide, butyl stearate, monoglyceride stearate, pentaerythritol tetrastearate, hydrogenated castor oil, stearyl stearate, siloxane, higher alcohol type Molecule, stearyl alcohol, calcium stearate, zinc stearate, magnesium stearate, lead stearate silicone (dimethylsiloxa ) Based low molecular weight compound (oil) or silicone (dimethylsiloxane) -based resins., These other which may be used alone, or may be used in combination of two or more if necessary. Of these, silicone-based low molecular weight substances (oils) and silicone-based resins are particularly recommended. This is because the dynamic friction coefficient of the film surface is reduced, the change of the friction coefficient before and after the hot water treatment is small, and the solvent adhesiveness of the film is hardly hindered.

  Here, the silicone type refers to organosiloxanes, which are oily, rubbery, and resinous, and are called silicone oil, silicone rubber, and silicone resin, respectively. Since these all have a water repellent effect, a lubrication effect, a release action, etc., inclusion in the outermost layer portion of the film is effective in reducing the surface friction. In addition, when used as a beverage container label, it is often attached by heat-shrinking using steam or hot air. In a slippery layer with low water resistance, the heat-shrinking treatment using steam causes a decrease in slipperiness. Although it is easy, good slipperiness can be maintained even after the steam treatment due to the water repellent effect inherent in silicone.

  Particularly preferred among silicones is a silicone resin. Silicone resin refers to a network structure in which organopolysiloxane is three-dimensionally bonded, and is formed on the surface of a polyester film as an easy-sliding layer, and then rolled into a roll shape to contact the back surface of the film. Make transcription difficult to occur. In addition, when used as a beverage label, the surface is subjected to a printing process, but the printability is rare. Among silicone resins, those having a methyl group as an organic group in the molecule are particularly recommended because they are excellent in heat resistance and suitable for hot beverage container labels.

  The content of the silicone resin is preferably 10 to 80% by weight, more preferably 20 to 70%, as the abundance in the easy-slip layer. If the content is less than 10% by weight, the effect of improving the slipperiness is small, and if it exceeds 80% by weight, the easy-slip layer component is easily transferred to the back surface when rolled.

Furthermore, it is recommended that the easy-slip layer component contains a resin component having a binder function.
Examples of the resin component include polyester resins, polyamide resins, polyurethane resins, epoxy resins, phenol resins, acrylic resins, polyvinyl acetate resins, polyolefin resins such as polyethylene and polypropylene, and copolymers thereof. Or a modified resin, a cellulose resin, etc. are mentioned. Moreover, since the resin used as the binder in the present invention needs water resistance, it is essential that the resin be essentially water-insoluble.
In particular, it is preferable to use a hydrophobic copolyester resin as a backbone polymer. The graft polymerization reaction product obtained by graft polymerization of the polyester resin with a radical polymerizable monomer in an organic solvent, adding water and distilling off the organic solvent is excellent in adhesion and water resistance, and is a water-dispersed resin. It is recommended because it is a form and is preferable from the viewpoint of work environment and applicability. As a preferable polyester resin component of the trunk polymer, an aromatic dicarboxylic acid such as terephthalic acid, isophthalic acid or 2,6-naphthalenedicarboxylic acid, an aliphatic dicarboxylic acid such as adipic acid, azelaic acid or sebacic acid as a dicarboxylic acid component In addition to the component selected from the components, it is preferable to contain about 0.5 to 10 mol% of a component having a polymerizable unsaturated double bond such as fumaric acid, maleic acid, and 2,5-norbornene dicarboxylic acid. The glycol component is selected from aliphatic diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, and alicyclic glycols such as 1,4-cyclohexanedimethanol. It is preferable to contain a component. The graft site is composed of a polymerizable unsaturated monomer, but in addition to components selected from fumaric acid, maleic acid, maleic anhydride, acrylic acid, methacrylic acid, etc., styrene, α-methylstyrene, etc. It is preferable to contain a styrene-based compound because it exhibits superior lubricity in combination with the aforementioned lubricant.

  It is preferable to use water-soluble or water-dispersible lubricants and binder resin components from the viewpoints of safety and environmental friendliness.

The amount of the coating solution, the amount present on the film after stretching is preferably 0.002~0.5g / m ^2, more preferably from 0.005~0.4g / m ^2. 0
. Is less than 002g / m ^2, the slipping property is reduced, when it exceeds 0.5 g / m ^2, except that reduction of transparency of the film occurs, because there is a decrease of the solvent adhesion occurs, undesirable.

  As the in-line coating method, the fountain die coating / smoothing bar method is recommended in order to obtain the above coating amount uniformly and accurately. In order to satisfy the requirements of the present invention, the die lip gap is preferably in the range of 100 to 600 μm, and the nozzle gap is preferably in the range of 100 to 400 μm. It is preferable to use a smoothing bar that is of a rotary type and that has a fluctuation degree of fluctuation in rotational peripheral speed within ± 1%.

  In addition, in order to obtain a uniform coating amount in the longitudinal (longitudinal) direction of the film, it is applied in the form of a film having stable film properties in the length direction and the width direction as described above, and the coating property of the coating liquid. It is preferable to suppress fluctuations. For this purpose, it is effective to keep the fluctuation range of the surface energy of the coating liquid as small as possible.

  In the fountain die coating / smoothing bar method, the coating solution is supplied from the fountain die to the film. Next, an excess coating solution is scraped off using a smoothing bar so as to obtain a uniform coating amount. It is advantageous in terms of cost that the liquid scraped off at this time is returned to the tank and used again as a coating liquid. However, once it is supplied from the fountain die and scraped off, some of the easily volatile components volatilize, and the entire liquid composition often changes over time. Along with this, the surface energy of the liquid changes, which may lead to changes in coating properties and surface physical properties of the film.

In order to suppress the liquid composition fluctuation, a method of continuously adding volatilizing components and amounts is recommended.
However, when adding a volatile component, especially when using a water-dispersible resin or the like, care should be taken because the dispersion state of the liquid is often made unstable by the addition method. A method of suppressing the deterioration of dispersibility by a method of adding after diluting the component to be added or adding a droplet in a small size is preferable.

A specific example of producing a polyester film will be described. First, the raw material chips controlled to a size satisfying the means (■) are dried using a dryer such as a hopper dryer or paddle dryer, or a vacuum dryer, and extruded into a film at a temperature of 200 to 300 ° C. . Alternatively, an undried polyester raw material is similarly extruded into a film while removing moisture in a vented extruder. After extrusion, it is cooled with a casting roll (rapid cooling) to obtain an unstretched film. The “unstretched film” includes a film on which a tension necessary for film feeding is applied.

  The unstretched film is stretched. The stretching treatment may be performed continuously after cooling with a steam casting roll or the like, or may be wound after being cooled into a roll and then performed.

  In order to achieve the object of the present invention, it is practical in terms of production efficiency that the maximum shrinking direction is the film transverse (width) direction. Hereinafter, an example of a centrifugal method in which the main shrinking direction is the transverse direction will be described. Indicates. Even when the maximum shrinkage direction is the longitudinal (longitudinal) direction of the film, the film can be stretched according to ordinary operations such as changing the stretching direction by 90 ° in the following method.

  The heat shrink characteristics of a long film may vary due to process fluctuations when the film is stretched in addition to the film composition fluctuations described above. Reducing fluctuations in the heat shrinkage behavior of the long film is preferable because it leads to a reduction in the defective rate of products. In order to reduce the fluctuation of the heat shrinkage behavior, it is preferable to suppress the fluctuation of the temperature in the step of stretching the film and reduce the fluctuation range of the surface temperature of the film as much as possible.

  In the case of a polyester film, when it is uniaxially stretched in the transverse direction using a tenter, there are a preheating step before stretching, a stretching step, a heat treatment step after stretching, a relaxation treatment, a maximum stretching treatment step, and the like. In particular, in the preheating process, the stretching process, and the heat treatment process after stretching, the fluctuation range of the surface temperature of the film measured at an arbitrary point is controlled within an average temperature of ± 1 ° C. Is a preferred means for. More preferably, the average temperature is within ± 0.5 ° C.

  Temperature fluctuations in the preheating step, the drawing step, and the heat treatment step after drawing greatly influence the fluctuations in the heat shrinkage rate (maximum shrinkage direction and orthogonal direction) and the maximum heat shrinkage stress value. Therefore, when the fluctuation range of the surface temperature of the film in these steps is small, the film is stretched or heat-treated at the same temperature over the entire length of the film, and the heat shrinkage behavior becomes uniform. Of course, it is preferable that the fluctuation range of the surface temperature of the film is small also in the relaxation treatment and the maximum stretching treatment step.

In order to reduce the fluctuation of the film surface temperature, for example, a wind speed fluctuation suppression facility equipped with an inverter so that the wind speed of the hot air for heating the film can be controlled, or a low pressure of 500 kPa or less (5 kgf / cm ² or less) is used as the heat source. It is preferable to use equipment that can suppress temperature fluctuations of hot air using steam.

  The fluctuation range of the film surface temperature measured at an arbitrary point is, for example, the film surface temperature continuously during film production, for example, an infrared non-contact surface thermometer, after 2 m has passed since the drawing process. This is the range of fluctuation when measured by. Since the average temperature can be calculated when film production for one roll is completed, if the fluctuation range of the film surface temperature is within the average temperature ± 1 ° C., the film is stretched under the same conditions over the entire length of the steady region of the film. Therefore, the fluctuation of the heat shrinkage behavior is also reduced.

Moreover, when paying attention to uniforming the thickness distribution of the target heat-shrinkable polyester film, it is preferable to perform a preheating step prior to the stretching step when stretching in the transverse direction using a tenter or the like, In this preheating step, heating is performed at a low wind speed so that the thermal conductivity coefficient is 0.0013 calories / cm ² · sec · ° C. or less until the film surface temperature is within a range of Tg + 0 ° C. to Tg + 60 ° C. It is preferable to carry out.

  Stretching in the transverse direction is performed at a predetermined temperature within a range of Tg-20 ° C to Tg + 40 ° C, and is stretched 2.3 to 7.3 times, preferably 2.5 to 6.0 times. Thereafter, heat treatment is performed at a predetermined temperature in the range of 60 ° C. to 110 ° C. with 0-15% elongation or 0-15% relaxation, and as necessary at a predetermined temperature in the range of 40 ° C. to 100 ° C. Further heat treatment is performed to obtain a heat-shrinkable polyester film. In this transverse stretching step, it is preferable to use equipment capable of reducing the fluctuation of the film surface temperature as described above.

  As a stretching method, not only horizontal uniaxial stretching with a tenter, but also stretching in the longitudinal direction by 1.0 to 4.0 times, preferably 1.1 to 2.0 times may be performed. When biaxial stretching is performed in this manner, either sequential biaxial stretching or simultaneous biaxial stretching may be performed, and restretching may be performed as necessary. Further, in the sequential biaxial stretching, any of stretching methods such as vertical and horizontal, horizontal and vertical, vertical and horizontal and horizontal and vertical and horizontal directions may be used. Even when these longitudinal stretching steps or biaxial stretching steps are adopted, it is preferable to minimize the fluctuation of the film surface temperature as much as possible in the preheating step, the stretching step and the like, similarly to the transverse stretching.

From the viewpoint of suppressing the internal heat generation of the film accompanying stretching and reducing the film temperature unevenness in the width direction, the heat transfer coefficient of the stretching process is preferably 0.0009 calories / cm ² · sec · ° C. or more. . 0.0013 to 0.0020 calories / cm ² · sec · ° C. is more preferable.

  The heat-shrinkable polyester film roll in the present invention is preferably a roll obtained by winding a heat-shrinkable polyester film having a width of 0.2 m or more around a winding core (core) with a length of 300 m or more. A roll of a film having a width of less than 0.2 m has a low industrial utility value, and a film roll having a width of less than 300 m has a small film winding length, and thus covers the entire length of the film. Since the change in slipperiness and heat shrinkage behavior is reduced, the effect of the present invention is hardly exhibited. The width of the heat-shrinkable polyester film roll is more preferably 0.3 m or more, and further preferably 0.4 m or more. The length of the heat-shrinkable polyester film wound around the roll is more preferably 400 m or more, and further preferably 500 m or more.

  The upper limit of the width and the winding length of the film roll is not particularly limited, but from the viewpoint of ease of handling, the width is generally 1.5 m or less, and the winding length is preferably 6000 m or less when the film thickness is 45 μm. As the winding core, a plastic core such as 3 inch, 6 inch, or 8 inch, a metal core, or a paper tube can be usually used.

  The thickness of the film constituting the heat-shrinkable polyester film roll of the present invention is not particularly limited. For example, as the heat-shrinkable polyester film for labels, 10 to 200 μm is preferable, and 20 to 100 μm is more preferable. preferable.

  Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are not intended to limit the present invention, and modifications and implementations within the scope of the present invention are included in the present invention. In addition, the measuring method of the physical property of the film obtained by the Example and the comparative example is as follows.

(1) Confirmation of steady region and setting of sample cut-out portion From the second end portion (winding end portion) of the film about a film roll wound with a film having a length of 1000 m obtained in Examples and Comparative Examples described later. Samples of 5 points were cut out at intervals of 20 m, and samples of 5 points were cut out at intervals of 20 m from the inner part of the film from the first end (winding start part) of the film toward the first end, and the maximum shrinkage direction of these samples The thermal contraction rate (described later) of was measured. The variation of the heat shrinkage rate of each sample was within 20%. Moreover, the production / stretching process was stable during the production of the film. Therefore, it was confirmed that each film roll corresponds to the steady region over the entire length of the film.

(2) Thermal contraction rate in the maximum shrinkage direction The film is cut into a 10 cm × 10 cm square along the longitudinal direction and its orthogonal direction, and treated in warm water at 85 ° C. ± 0.5 ° C. for 10 seconds under no load condition. After heat shrinking, the sample was immediately immersed in water at 25 ° C. ± 0.5 ° C. for 10 seconds, and then the length of the sample in the vertical and horizontal directions was measured and determined according to the following formula. The direction with the largest shrinkage rate was defined as the maximum shrinkage direction.
Heat shrinkage rate (%) = 100 × (length before shrinkage−length after shrinkage) ÷ (length before shrinkage)

(3) Friction coefficient The dynamic friction coefficient μd between film surfaces was measured in an environment of 23 ° C. and 65% RH in accordance with JIS K-7125.
Regarding the coefficient of dynamic friction after the hot water treatment, the film was immersed in hot water at 80 ° C. for 10 seconds in the main shrinkage direction, dipped for 20 seconds, pulled up, and naturally dried in an atmosphere at 23 ° C. and relative humidity 65% for 24 hours. Then, the same measurement as described above was performed.

(4) Haze haze was measured using a haze meter (manufactured by Nippon Seimitsu Co., Ltd.) according to JIS K7136. The case where the haze was 8.0% or less was rated as ◯, and the case where it exceeded 8.0% was rated as x.

(5) Solvent adhesiveness 1,3-dioxolane was applied to one surface of the film, the other surface was pressure-bonded to the coated surface, and bonded into a tube shape. The tube was cut into a 15 mm length in the direction perpendicular to the flow direction during processing to obtain a sample, and a T-peel test in the above direction of the joint portion was performed under the condition of a tensile speed of 200 mm / min according to JIS K 6854. The solvent adhesion was evaluated based on the following criteria.

Peel adhesion strength 3N / 15mm or more: ○
Peel adhesion strength 1N / 15mm or more: △
Peeling adhesive strength less than 1N / 15mm: ×

Film roll 1
(Synthesis of polyester)
In a stainless steel autoclave equipped with a stirrer, thermometer and partial reflux condenser, 100 mol% of dimethyl terephthalate (DMT) as a dicarboxylic acid component, 70 mol% of ethylene glycol (EG) as a glycol component and neopentyl glycol (NPG) 30 mol% is charged so that glycol is 2.2 times the molar ratio of methyl ester, zinc acetate is 0.05 mol% (based on the acid component) as a transesterification catalyst, and polycondensation catalyst As a result, 0.025 mol% of antimony trioxide (based on the acid component) was added, and a transesterification reaction was carried out while distilling off the produced methanol outside the system. Thereafter, a polycondensation reaction was performed at 280 ° C. under a reduced pressure of 26.7 Pa to obtain a polyester A having an intrinsic viscosity of 0.73 dl / g, which was chipped.

  Polyester raw material chips B and C shown in Table 1 were obtained by the same method as for the polyester raw material chip A. In the table, BD is 1,4-butanediol. The intrinsic viscosity of the polyester chip B was 0.72 dl / g, and the intrinsic viscosity of the polyester chip C was 1.20 dl / g. In addition, when adding an inorganic lubricant in the experimental examples described later, the inorganic lubricant to be used was added to the polyester for chip B at a ratio of 0.7% by mass to obtain a master batch, and the required amount was used. . As a method for adding the lubricant, a method was used in which the lubricant was previously dispersed in ethylene glycol and polymerized by the above method.

  Each separately preliminarily dried polyester chip A shown in Table 1 was fed 66% by mass, B was 9% by mass, and C was 25% by mass. Then, they were mixed in a hopper, melt-extruded with a single-screw extruder at 280 ° C., and rapidly cooled to obtain an unstretched film having a thickness of 180 μm. At this time, the capacity of the hopper was 150 kg in terms of the raw material weight, the extrusion amount of the extruder was 450 kg per hour, and the inclination angle of the hopper was 70 degrees.

(Preparation of coating solution)
The solid content of dimethyl silicone resin (SE4005 manufactured by Nissin Chemical Laboratory) is 70% by mass in the total solid content of the coating liquid, and the solid content of the aqueous dispersion of copolymerized polyester resin (AGN702 manufactured by Toyobo) is 20% by mass. %, 100 kg of an aqueous liquid containing 10% by mass of solid content of acetylene glycol derivative (Surfinol 486 manufactured by Shin-Etsu Chemical Co., Ltd.) and 20% by mass of isopropanol was prepared and charged into the tank.

  A coating solution is applied to the unstretched film by a fountain die coating / smoothing bar method, a die lip gap of 320 μm, a nozzle gap of 200 μm, and a smoothing bar having a diameter of 8 mm. Then, the coating solution was supplied. In the tank, a mixed solution of water / isopropyl alcohol = 50/50 was continuously added in an amount of 80 g / min.

Subsequently, the coating film was pre-heated at 100 ° C. for 10 seconds with a tenter, then stretched 4.0 times in the transverse direction at 80 ° C., and heat-treated at 80 ° C. for 10 seconds, continuously having a thickness of 45 μm and a coating amount of 0 A heat-shrinkable polyester film having a thickness of 0.02 g / m ² was formed. The temperature fluctuation of the film surface when the film is continuously formed 1000 m is the average temperature ± 0.7 ° C. in the preheating step, the average temperature ± 0.5 ° C. in the stretching step, and the average temperature ± 0.5 ° C. in the heat treatment step. It was in the range.

  The obtained film was slit to a width of 0.5 m and a length of 1000 m and wound around a 3-inch paper tube to obtain a heat-shrinkable film roll. Tables 1 and 2 show the physical property values of the film of the obtained film roll.

Film roll 2
Regarding the coating solution, the solid content of the silicone water dispersion (TSM6343 manufactured by Toshiba Silicone) is 70% by mass in the total solid content of the coating solution, and the solid content of the polyester resin aqueous dispersion (Vylonal MD1500 Toyobo) is 20% of the solid content. In the same manner as film roll 1 except that the coating liquid was an aqueous liquid containing 10% by mass of solid content of acetylene glycol derivative (Surfinol 485 manufactured by Shin-Etsu Chemical Co., Ltd.) and 20% by mass of isopropanol. A heat-shrinkable film roll was obtained. Table 2 shows the physical property values of the film of the obtained film roll.

Film roll 3
About coating liquid, solid content of amino acid type amphoteric activator aqueous solution (manufactured by Bister SLA Matsumoto Yushi) is 90% by mass in total solid content in coating liquid, solid content of polyester resin in water dispersion (byronal MD1500 Toyobo) is solid A heat-shrinkable film roll was obtained in the same manner as the film roll 1 except that the coating liquid was an aqueous liquid containing 10% by mass and 20% by mass of isopropanol. Table 2 shows the physical property values of the film of the obtained film roll.

Film roll 4
Regarding the coating liquid, the solid content of the aqueous sulfonate solution (TB214 Matsumoto Yushi) is 90% by mass in the total solid content of the coating liquid, and the solid content of the aqueous dispersion of copolymerized polyester resin (AGN709 manufactured by Toyobo) is the solid content. A heat-shrinkable film roll was obtained in the same manner as in Example 1 except that an aqueous solution containing 10% by mass and isopropanol 20% by mass was used as the coating solution. Table 2 shows the physical property values of the film of the obtained film roll.

Film roll 5
A heat-shrinkable film roll was obtained by the same method except that the coating liquid was not applied in the film roll 1. Table 2 shows the physical property values of the film of the obtained film roll.

Film roll 6
A heat-shrinkable film roll was obtained in the same manner as in Example 1 except that the additive additive solution in film roll 1 was 100% water. Table 3 shows the physical property values of the film of the obtained film roll.

Film roll 7
A heat-shrinkable film roll was obtained in the same manner as in Example 1 except that the additive additive solution was changed to 100% isopropyl alcohol in Example 1. Table 3 shows the physical property values of the film of the obtained film roll.

Film roll 8
A heat-shrinkable film roll was obtained in the same manner as in Example 1 except that no additional additive solution was added to the film roll 1. Table 3 shows the physical property values of the film of the obtained film roll.

In the film roll 7, clogging of the liquid occurred in the fountain, and coating spots could be visually confirmed during the process.
About the film rolls 1-5, the cylindrical label of height 180mm and circumference 220mm was created. About 1-4, the coat layer side was made to become an outer surface.
Using a steam tunnel made by Fuji Astec Inc (model: SH-1500-L), the above label was passed through for 15 seconds, at a first zone temperature of 70 ° C., a second zone temperature of 75 ° C., and a third zone temperature of 82 ° C., and 500 ml It was heat-shrinked and attached to a PET bottle beverage. When the film rolls 1 and 2 were put into the vending machine, there was no clogging out of 500 pieces in the film rolls 1 and 2, and 6 pieces out of 500 pieces in the film roll 3 and film roll 4 were clogged. Clogging occurred.

  When the heat-shrinkable film roll of the present invention is used as a label for a beverage container by heat-shrinking treatment, friction between containers can be kept low, and it is generated due to slippage in the film roll and variations in surface characteristics. It is possible to prevent the occurrence of defects due to clogging or the like in the vending machine. In addition, the film is excellent in film formability and processability and is useful in industrial production.

Claims (7)

A film roll formed by winding a heat-shrinkable polyester film, wherein the heat-shrinkable polyester film satisfies the following requirements (1) and (2): .
(1) When the winding start end of the film in the steady region where the film properties are stable in the length direction of the film is the first end, and the end on the winding end is the second end, The first sample cutout portion is provided within 2 m inside the two end portions, and the final cutout portion is provided within 2 m inside the first end portion, and the sample cutout portion is provided approximately every 100 m from the first sample cutout portion. Each sample cut into a square shape of 10 cm × 10 cm was dipped in hot water at 85 ° C. for 10 seconds, then dipped in water at 25 ° C. for 10 seconds, and then heat shrinkage in the maximum heat shrink direction. The rate is 20% or more for all samples.
(2) For each sample separately cut out from each sample cut-out section described in (1) above, the coefficient of dynamic friction (μd) between at least one surface of the cut out samples is 0.27 or less in all the samples. And after the film was immersed in hot water at 80 ° C. in the main shrinkage direction for 10 seconds while being thermally shrunk for 20 seconds, pulled up, and naturally dried in an atmosphere of 23 ° C. and relative humidity 65% for 24 hours, At least the dynamic friction coefficients between one side of the film are all 0.30 or less. The heat-shrinkable polyester film according to claim 1, wherein the heat-shrinkable polyester film is a film roll formed by winding a heat-shrinkable polyester film, and the heat-shrinkable polyester film satisfies the following requirement (3). Film roll.
(3) About each sample cut out separately from each sample cut-out part described in claim 1 (1), the cut out film is immersed for 20 seconds in the main shrinkage direction in hot water at 80 ° C. for 10 seconds. Then, when the average value of the dynamic friction coefficient between at least one side of the film after being naturally dried for 24 hours in an atmosphere of 23 ° C. and relative humidity of 65% is calculated, μd of all the samples is this average value. It is within the range of ± 0.06.   The heat-shrinkable polyester film roll according to claim 1 or 2, wherein an easy-slip layer containing a lubricant component is provided as an outermost layer on at least one side of the film.   The heat-shrinkable polyester film roll according to claim 3, wherein the easy-slip layer is provided by a coating method.   The heat-shrinkable polyester film roll according to any one of claims 1 to 4, wherein the film can be bonded to a solvent.   The heat-shrinkable polyester film roll according to any one of claims 3 to 5, wherein the easy-slip layer contains a silicone component.   A heat-shrinkable label produced from the heat-shrinkable polyester film roll according to any one of claims 1 to 6.