JP2006348152A - Heat-shrinkable polyester film, and heat-shrinkable label and container using the film - Google Patents

Abstract

The present invention provides a heat-shrinkable polyester film having excellent heat-shrinkability and shrink finish, and excellent heat resistance, and particularly excellent resistance to breakage in printing and tubing processes.
SOLUTION: The polyester resin (A) obtained from an alicyclic dicarboxylic acid component and an alicyclic diol component contains 5% by mass or more based on the polyester resin composition, and is immersed in warm water at 80 ° C. for 10 seconds. After that, the heat shrinkage rate in the main shrinkage direction when immersed and cooled in water at 23 ° C. for 30 seconds is 20% or more, a plurality of predetermined strip-shaped test pieces are cut out, and a tensile test is performed in a direction perpendicular to the main shrinkage direction. The test specimens having a breaking elongation of 400% or more in all test pieces and having a breaking elongation of 100% or more after being stored for 2 weeks in an atmosphere at a temperature of 45 ° C. and a relative humidity of 30% are obtained. It is 80% or more of the number of test pieces.
[Selection figure] None

Description

  The present invention relates to a heat-shrinkable polyester film, and more particularly, particularly excellent in tear resistance at the time of printing or tubing, and also has defects such as whitening and shrinkage unevenness after heat shrinkage, wrinkles, distortion, and vertical shrinkage. The present invention relates to a heat-shrinkable polyester film that generates little and has excellent heat resistance, a heat-shrinkable label using the film, and a container equipped with the label.

  Currently, heat-shrinkable plastic films are widely used for shrink wrapping and shrinkage labels such as polyethylene terephthalate containers, polyethylene containers, and glass containers. Examples of the heat-shrinkable plastic film include stretched films such as a polyvinyl chloride film, a polystyrene film, and a polyester film. However, the polyvinyl chloride film has problems such as low heat resistance, generation of hydrogen chloride gas during incineration, and easy damage to the incinerator. In addition, the polystyrene film has excellent finished appearance after shrinkage, but has problems such as poor solvent resistance.

  The polyester film has excellent performance such as good transparency, excellent hygiene, and high rigidity. However, as the temperature rises, there is a problem that the shrinkage rate increases rapidly. When a container with large irregularities is coated, the coating is insufficient or wrinkles occur, resulting in a good finish. There was no problem.

  On the other hand, it is known that the use of a polyester film having a predetermined heat shrinkage and elongation at break can suppress the occurrence of defects such as wrinkles, distortion, and vertical draw (Patent Document 1, etc.). reference). However, in a uniaxial film-forming product that shrinks in one direction as described in Patent Document 1 and the like, the speed is increased in the direction perpendicular to the main shrinkage direction (the flow direction in the heat-shrinkable film manufacturing / processing process). When processed, there was a problem that the film was easily broken. In particular, in the printing process and the tubing process in the uniaxial film-formed product, once a problem of breakage occurs, it takes time to recover, and thus the improvement in productivity in the printing and tubing processes has been a major issue.

JP 2003-41028 A

  This invention is made | formed in view of the subject of the said prior art, and the subject of this invention is a film with the favorable shrinkage | contraction characteristic and shrinkage | contraction finishing, and excellent in heat resistance (high fusion start temperature). Another object of the present invention is to provide a heat-shrinkable polyester film having little mechanical deterioration with time and excellent tear resistance during printing and tubing.

  Another object of the present invention is to provide a heat-shrinkable label having a good shrink finish and a beautiful appearance, and a container equipped with the label.

  As a result of intensive investigations on the balance between shrink finish and tear resistance of the heat-shrinkable polyester film, the present inventors, as a polyvalent carboxylic acid component, as an alicyclic dicarboxylic acid component, as a polyhydric alcohol component, By using a polyester resin composition containing 5% by mass or more of a polyester resin using an alicyclic diol component, the shrinkage rate in the main shrinkage direction during heating is within a specific range, and breaks during printing and tubing It has been found that a heat-shrinkable polyester film excellent in fracture resistance that does not generate cracks can be obtained.

  That is, the subject of the present invention is a heat-shrinkable polyester film obtained from a polyester resin composition comprising a polyester resin (A) obtained from an alicyclic dicarboxylic acid component and an alicyclic diol component, The main shrinkage direction when the content of the polyester resin (A) with respect to the polyester resin composition is 5% by mass or more, and after being immersed in warm water at 80 ° C. for 10 seconds and then immersed and cooled in water at 23 ° C. for 30 seconds. A plurality of strip-shaped test pieces having a heat shrinkage rate of 20% or more, a length in the main shrinkage direction of 15 mm, and a length in the direction perpendicular to the main shrinkage direction of 100 mm, and a direction perpendicular to the main shrinkage direction. The breaking elongation when tensile test is performed at a distance between chucks of 20 mm, a temperature of 23 ° C. and a tensile speed of 200 mm / min is 400% or more in all test pieces, and After being stored in an atmosphere of 45 ° C. and a relative humidity of 30% for 2 weeks, the breaking elongation when a plurality of test pieces cut out in the same shape as described above is subjected to a tensile test under the same conditions as described above is 100% or more. This is achieved by a heat-shrinkable polyester film (hereinafter referred to as “film of the present invention”) characterized in that the number of test pieces is 80% or more of the total number of test pieces.

  The film of the present invention is obtained from a polyester resin composition comprising the polyester resin (A) and a polyester resin (B) containing 65 mol% or more and 97 mol% or less of a terephthalic acid-ethylene glycol unit, The mixing ratio of the polyester resin (A) and the polyester resin (B) is preferably% by mass and A / B = 5/95 to 99/1.

  In the film of the present invention, the alicyclic dicarboxylic acid component is preferably 1,4-cyclohexanedicarboxylic acid, and the alicyclic diol component is preferably 1,4-cyclohexanedimethanol.

  Another object of the present invention is achieved by a heat-shrinkable label using the heat-shrinkable polyester film as a base material and a container equipped with the heat-shrinkable label.

  Since the film of the present invention has good shrinkage characteristics, it has excellent shrinkage finish, and there are few breakage troubles in printing and tubing processes using a heat-shrinkable film, and high-speed processing is possible.

  The film of the present invention contains at least 5% by mass of a polyester-based resin composed of an alicyclic dicarboxylic acid component as a polyvalent carboxylic acid component and an alicyclic diol component as a polyhydric alcohol component with respect to the total mass of the resin. Accordingly, it is possible to improve the tear resistance while maintaining an appropriate solvent resistance, and it is possible to process at a high speed in the printing and tubing processes using the solvent. Furthermore, since heat resistance (melting start temperature) is also improved, according to the present invention, it is possible to provide a heat-shrinkable polyester film that is also optimal for a heating application label.

  Further, since the heat-shrinkable label and container of the present invention are based on the film of the present invention, according to the present invention, the heat-shrinkability is excellent in shrinkage finish, excellent in tear resistance, and beautiful in appearance. Labels and containers can be provided.

  Hereinafter, the heat-shrinkable polyester film of the present invention, the heat-shrinkable label, and the container equipped with this label will be described in detail.

[Heat-shrinkable polyester film]
The film of the present invention comprises a polyester resin (A) obtained from an alicyclic dicarboxylic acid component as a polyvalent carboxylic acid component and an alicyclic diol component as a polyhydric alcohol component, and a polyester resin constituting the film of the present invention. 5 mass% or more is included with respect to the mass of the whole composition.

  The said alicyclic dicarboxylic acid component means the component which comprises a dicarboxylic acid residue, when it is set as a polyester-type resin, and alicyclic dicarboxylic acid, alicyclic dicarboxylic acid ester, etc. are mention | raise | lifted. The alicyclic diol component refers to a component constituting a diol residue when a polyester resin is used, and examples thereof include an alicyclic diol.

  In general, it is known that film breakage due to embrittlement is caused by embrittlement deterioration due to a solvent in addition to embrittlement due to temperature and humidity. Usually, in order to prevent embrittlement deterioration due to a solvent, it is preferable to use a polyester-based resin having high solvent resistance. However, since the polyester-based resin having high solvent resistance itself is brittle, a film made of such a resin has a problem that it is easily broken.

  Therefore, in the present invention, in order to eliminate such drawbacks, if the polyester resin composition contains 5% by mass or more of the polyester resin (A), the polyester resin composition has a resistance to tearing while maintaining an appropriate solvent resistance. Can be improved. As a result, the film of the present invention has few breakage troubles in the printing and tubing process using a solvent and can be processed at high speed. The film of the present invention preferably contains 7% by mass or more, more preferably 10% by mass or more of the polyester resin (A). The upper limit of the content of the polyester-based resin (A) is not particularly limited and may be 100% by weight. However, when other resins are mixed, 99% by weight or less is preferable, and 95% by weight or less is more preferable. A mass% or less is more preferable.

  In addition, the film of the present invention has a thermal shrinkage rate of 20% or more when immersed in 80 ° C. warm water for 10 seconds and then immersed and cooled in 23 ° C. water for 30 seconds. This heat shrinkage rate of 20% or more is a condition necessary for obtaining good heat shrinkage characteristics and obtaining a good shrinkage finish after packaging in containers such as PET bottles and glass bottles, and is 30% or more. More preferably, it is more preferably 40% or more. On the other hand, if the heat shrinkage rate is too high, wrinkles or distortions occur in the film and the shrinkage finish becomes poor, so the upper limit of the heat shrinkage rate is preferably about 70%.

  From the viewpoint of improving the low temperature shrinkability, the film of the present invention has a thermal shrinkage ratio of 10 when immersed in warm water at 70 ° C. for 10 seconds and then cooled by immersion in water at 23 ° C. for 30 seconds. % Or more, preferably 20% or more, and 35% or less, preferably 30% or less. By setting the heat shrinkage rate in the main shrinkage direction at 70 ° C. to 10% or more, shrinkage unevenness that may occur locally when a bottle is attached with a steam shrinker is suppressed, resulting in formation of wrinkles, avatars, etc. Can be suppressed. Further, by setting the upper limit of the heat shrinkage rate at 70 ° C. to 35% or less, extreme shrinkage at a low temperature can be suppressed, and for example, natural shrinkage can be kept small even in a high temperature environment such as summer. Further, the thermal shrinkage rate in the direction orthogonal to the main shrinkage direction of the film when immersed in warm water at 70 ° C. for 10 seconds is preferably 10% or less, more preferably 5% or less, and 3% or less. More preferably.

  In the present specification, the “main shrinkage direction” means a direction in which the thermal shrinkage rate is large in the longitudinal direction (longitudinal direction) of the film and the lateral direction (width direction) of the film. Means a direction corresponding to the outer circumferential direction, and “orthogonal direction” means a direction perpendicular to the main contraction direction.

  In the film of the present invention, a plurality of strip-shaped test pieces having a length in the main shrinkage direction of 15 mm and a length in the direction perpendicular to the main shrinkage direction of 100 mm are cut out, and the distance between chucks in the direction perpendicular to the main shrinkage direction is cut out. After breaking at 20 mm, a temperature of 23 ° C., and a tensile test at a tensile speed of 200 mm / min, the elongation at break is 400% or more in all the test pieces, and stored for 2 weeks in an atmosphere at a temperature of 45 ° C. and a relative humidity of 30%. When a plurality of test pieces cut into the same strip shape as described above are subjected to a tensile test under the same conditions as described above, the test piece having a breaking elongation of 100% or more is 80% or more of the total number of test pieces. Thereby, tear resistance can be improved. On the other hand, the upper limit of the breaking elongation is 1000% or less, preferably 900% or less, and more preferably 800%. This is because it is difficult to obtain a film having a breaking elongation exceeding 1000%.

  The film of the present invention has an elongation at break of 400% or more in all test pieces when subjected to a tensile test in the same manner as described above after ink application, in an atmosphere at a temperature of 45 ° C. and a relative humidity of 30%. After storing for 3 days, a plurality of test pieces cut out in the same shape as described above were subjected to a tensile test under the same conditions as described above, and the test piece having a breaking elongation of 100% or more was 80% or more of the total number of test pieces. It is preferable that If what satisfies the elongation at break under such conditions is 80% or more of the total number of test pieces, the film of the present invention can be provided with high break resistance at the time of printing. On the other hand, the upper limit of the breaking elongation is 1000% or less, preferably 900% or less, and more preferably 800%. This is because it is difficult to obtain a film having a breaking elongation exceeding 1000%.

  When it is desired to improve the solvent resistance and rupture resistance of the film of the present invention, the film is formed although it differs somewhat depending on the type of resin (for example, polyester resin (B)) to be combined with the polyester resin (A). This can be achieved by increasing the content of the polyester resin (A) relative to the entire resin.

  In this specification, the storage condition of “2 weeks in an atmosphere at a temperature of 45 ° C. and a relative humidity of 30%” is a normal storage in a test for evaluating the elongation at break (breaking resistance) over time. The storage temperature is higher than the upper temperature limit of 25 ° C., which is an extremely severe condition. The fact that the test piece having a breaking elongation of 100% or more in the tensile test after storage under such conditions is 80% or more of the total number of test pieces is strong in the heat shrinkable film printing and tubing steps, There is almost no breakage trouble, thinning and high-speed processing are possible, and it can be a heat-shrinkable polyester film having no problem of tearing after production. That is, the film of the present invention is less prone to breakage troubles over time at each stage from the production of heat-shrinkable polyester film to the production / processing of heat-shrinkable film and packaging in containers, and the productivity. Can be improved. This effect is so good that the test piece which is 100% or more of elongation at break becomes close to 100%, 85% or more is preferable, 90% or more is more preferable, and 95% or more is further more preferable.

  Further, in this specification, “the test piece having a breaking elongation of 100% or more is 80% or more of the total number of test pieces” means that the test piece number is 5 or more, preferably 10 or more. 4 or more (eight or more when 10 sheets are used) means that the elongation at break is 100% or more.

  The alicyclic dicarboxylic acid component as the polyvalent carboxylic acid component of the polyester resin (A) is not particularly limited. For example, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, or ester derivatives thereof may be used. Can be mentioned. Cyclohexanedicarboxylic acid has a cis configuration and a trans configuration, but may have any configuration from cis isomer 100% to trans isomer 100%, and all combinations of cis isomer and trans isomer are possible. included. Of these, 1,4-cyclohexanedicarboxylic acid or an ester derivative thereof is preferable from the viewpoint of heat shrinkability and heat resistance, and the trans isomer is 20% to 100%, particularly 80% to 100%. -More preferred are cyclohexanedicarboxylic acid or ester derivatives thereof.

  In addition, the alicyclic diol component as the polyhydric alcohol component of the polyester resin (A) is not particularly limited, and 1,1-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, Examples thereof include 1,4-cyclohexanedimethanol, 1,2-cyclohexanediol, 1,4-cyclohexanediol, and among these, 1,4-cyclohexanedimethanol is particularly preferable. Cyclohexanedimethanol has a cis isomer and a trans steric configuration, but may be in any range from cis isomer 100% to trans isomer 100%, and all combinations of cis isomer and trans isomer are included. included. Among these, 1,4-cyclohexanedimethanol is preferable from the viewpoint of heat resistance, and 1,4-cyclohexanedimethanol having a trans isomer of 50% to 100% is more preferable.

  Since the polyester-based resin (A) is composed of the alicyclic dicarboxylic acid component and the alicyclic diol component as described above, the improvement in solvent resistance due to appropriate crystallinity and the appropriate glass transition point (Tg). Have. The polyester resin (A) preferably has a Tg of 60 ° C. or higher measured by a differential scanning calorimeter (DSC) from the viewpoint of imparting heat resistance to the obtained heat-shrinkable film. On the other hand, the upper limit is not particularly limited, but is preferably 80 ° C. or less from the viewpoint of ease of molding. The Tg of the polyester resin (A) is that the polyester resin (A) is melted at 280 ° C. for 5 minutes, then immersed in liquid nitrogen, quenched, and non-crystallized as a sample. It can be measured using DSC at / min.

  The film of the present invention contains at least 5% by mass of the polyester resin (A) composed of the alicyclic dicarboxylic acid component and the alicyclic diol component as described above with respect to the total mass of the polyester resin composition. However, it may further include a polyester resin (B) containing 65 mol% or more and 97 mol% or less of a terephthalic acid-ethylene glycol unit.

  When the polyester-based resin (B) is contained, the mixing ratio of the polyester-based resin (A) and the polyester-based resin (B) in the resin constituting the film is mass%, and A / B = 5/95 to 99. / 1, preferably 7/93 to 95/5, more preferably 10/90 to 90/10. By setting the mass% ratio of the polyester resin (A) and the polyester resin (B) in the range of 5/95 to 99/1, the ink adhesion at the time of printing is maintained and the rupture resistance at the time of printing is improved. It is preferable because it can be used.

  The polyvalent carboxylic acid component constituting the polyester resin (B) preferably contains an aromatic dicarboxylic acid component as a main component. Examples of the aromatic dicarboxylic acid constituting the aromatic dicarboxylic acid component include terephthalic acid, isophthalic acid, orthophthalic acid, phenylenedioxydiacetic acid, 4,4′-diphenyldicarboxylic acid, 4,4′-diphenoxyethanedicarboxylic acid, Examples include 4,4′-diphenyl ether dicarboxylic acid, 4,4′-diphenylsulfone dicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and ester derivatives thereof. Among these, when terephthalic acid is used, high crystallinity is exhibited, and a heat-shrinkable polyester film can be ensured with sufficient strength, which is particularly preferable.

  In the present specification, “main component” means a total of 100 mol% of all dicarboxylic acid components or all diol components in dicarboxylic acids or diols contained in all dicarboxylic acid components or all diol components constituting the polyester-based resin. Refers to a component occupying a content of 50 mol% or more, preferably 60 mol% or more.

  The polyester resin (B) used in the film of the present invention may be copolymerized with a polycarboxylic acid other than the above-described dicarboxylic acid or its ester derivative within a range not impairing the effects of the present invention. Examples of the polyvalent carboxylic acid include aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, azelaic acid, and sebacic acid, and ester derivatives thereof.

  Moreover, it is preferable that the polyhydric alcohol component which comprises the polyester-type resin (B) used with the film of this invention has aliphatic diol as a main component. Specific examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, , 6-hexanediol, 1,10-decanediol, 2,2-dimethyl-1,3-propanediol, diethylene glycol, 1,1-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedim Methanol, 1,4-cyclohexanedimethanol and the like can be exemplified, among which ethylene glycol and 1,4-cyclohexanedimethanol are preferably used.

  The polyester-based resin (B) can also be copolymerized with an appropriate amount of diethylene glycol as a polyhydric alcohol component. Diethylene glycol is useful because it can lower the Tg of the polyester resin (B) and impart appropriate shrinkage characteristics to a film using the polyester resin (B) as a raw material.

  Furthermore, the polyester resin (B) is, for example, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyphenyl) propane, 2,2-bis, as long as the effects of the present invention are not impaired. Aromatic diols derived from (4′-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfone, etc .; glycolic acid, p-hydroxybenzoic acid, Hydroxycarboxylic acids and alkoxycarboxylic acids derived from p-β-hydroxyethoxybenzoic acid and the like; monofunctional groups derived from stearic acid, stearyl alcohol, benzyl alcohol, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid and the like A diol having tricarbaric acid, hexanetricarbo Acid, trimellitic acid, trimesic acid, pyromellitic acid, benzophenonetetracarboxylic acid, naphthalenetetracarboxylic acid, 1,2,6-hexanetriol, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, sorbitol, dipenta A diol having a trifunctional or higher polyfunctional group derived from erythritol, polyglycerol or the like may be copolymerized.

  When the polyvalent carboxylic acid component is terephthalic acid and the polyvalent diol component is ethylene glycol, the polyester resin (B) has a terephthalic acid-ethylene glycol unit of 65 mol% or more, preferably 70 mol% or more. And not more than 97 mol%, preferably not more than 90 mol%. If the terephthalic acid-ethylene glycol unit is contained in an amount of 65 mol% or more, a heat-shrinkable film having a firmness and a good shrinkage finish can be obtained. Moreover, if the said unit is 97 mol% or less, printability can be improved and it is preferable.

  The polyester resins (A) and (B) used in the present invention have an intrinsic viscosity measured at 30 ° C. in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (mass ratio 1: 1), Usually, it is 0.4 dl / g or more, preferably 0.6 dl / g or more, and 1.5 dl / g or less, preferably 1.2 dl / g or less. If the intrinsic viscosity of the polyester resin is 0.4 dl / g or more, sufficient mechanical properties can be obtained, and if the intrinsic viscosity is less than 1.5 dl / g, good moldability can be obtained.

  The polyester-based resins (A) and (B) used in the film of the present invention are prepared by a conventional method for producing a polyester-based resin, that is, a production method such as a direct polymerization method or a transesterification method. It can be manufactured by such a method.

  The resin obtained by the polycondensation reaction is usually extracted in the form of a strand from an extraction port provided at the bottom of the polycondensation reaction tank, and is cooled with water or after water cooling, and then cut into a pellet by cutting with a cutter. Furthermore, by subjecting the pellets after polycondensation to heat treatment and solid phase polycondensation, the degree of polymerization can be further increased, and reaction by-products such as acetaldehyde and low-molecular oligomers can be reduced.

  In the production method, the esterification reaction is performed using an esterification reaction catalyst such as antimony trioxide, an organic acid salt such as antimony, titanium, magnesium, calcium, or an organic metal compound, if necessary. The transesterification reaction can be carried out using a transesterification reaction catalyst such as an organic acid salt or an organic metal compound such as lithium, sodium, potassium, magnesium, calcium, manganese, titanium, or zinc, if necessary. Can do.

  The polycondensation reaction is performed in the presence of phosphorus compounds such as orthophosphoric acid, phosphorous acid, hypophosphorous acid, polyphosphoric acid, and esters and organic acid salts thereof, and, for example, antimony trioxide, germanium dioxide, It can be carried out using a metal oxide such as germanium tetroxide, or a polycondensation catalyst such as an organic acid salt or an organic metal compound such as antimony, germanium, zinc, titanium or cobalt.

  Among these polycondensation catalysts, in particular, one or more selected from tetrabutoxy titanium, diantimony trioxide, and germanium dioxide are preferably used. Furthermore, an antifoaming agent such as silicone oil can be added to promote defoaming in the polymerization process. The catalyst amount is usually 5 mass ppm or more and 2000 mass ppm or less as a metal amount (atomic conversion amount) with respect to the theoretical yield of the obtained polyester-based resin for both the esterification reaction catalyst, the transesterification reaction catalyst, and the polycondensation catalyst. Preferably, it is used in the range of 10 ppm to 500 ppm by mass.

The film of the present invention can be produced by a known method as will be described later. At that time, at least the polyester resin (A) is 5% by mass with respect to the total mass of the resin constituting the film. The polyester resin (B) must be blended and used.
However, as a method for incorporating the polyvalent carboxylic acid component and the polyhydric alcohol component of the polyester resin (B) into the film as a polyester resin component, these components are blended so as to have a desired composition. Prepare a single polyester resin by copolymerization and a plurality of raw polyester resins that are homopolyesters or copolyesters with different compositions, and mix them at a ratio that gives the desired composition. Any method of blending to obtain a polyester resin may be used. Among these, the blend method has an advantage that the composition of the film can be easily changed only by changing the blend ratio, and it can cope with the industrial production of various kinds of films.

  The film of the present invention preferably contains inorganic and / or organic fine particles from the viewpoint that when the film is a heat-shrinkable film, the film can be imparted with blocking resistance and slipperiness. The content of the fine particles is 0.005% by mass or more, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, and 1% by mass or less, based on the total mass of the polyester resin. Preferably it is 0.6 mass% or less, More preferably, it is desirable that it is the range of 0.5 mass% or less.

  Specific examples of the inorganic fine particles include silica, alumina, titania, kaolin, clay, calcium carbonate, calcium phosphate, lithium fluoride, carbon black, and alkali metal, alkaline earth metal, and phosphorus compound during polymerization of polyester. And the like resulting from a catalyst such as the above. Examples of the organic fine particles include various crosslinked polymers.

The average particle diameter of the organic or inorganic fine particles is 0.5 μm or more, preferably 1.0 μm or more, and 10 μm or less, preferably 8 μm or less, from the viewpoint of obtaining the above-described effects of blocking resistance and slipperiness. More preferably, it is in the range of 5 μm or less.
The “average particle size” as used herein means a 50% volume average particle size (d50) measured by a method such as a laser diffraction method, an electromagnetic wave scattering method such as a dynamic light scattering method, or a light transmission method such as a centrifugal sedimentation method. ), But if there is a difference depending on the measurement method, use the value determined by the laser diffraction method.

  The method for mixing the organic or inorganic fine particles is not particularly limited, and can be added during the polymerization process of the polyester resin, or can be mixed during the production process of the polyester resin composition or the molding process of the heat-shrinkable polyester film. You can also.

  The film of the present invention may further contain other resins as long as the effects of the present invention are not impaired. Examples thereof include polyolefin resins such as polyethylene, polypropylene, their modified maleic anhydride, and ionomers, thermoplastic resins such as polyamide resins and polystyrene resins, and thermoplastic elastomers.

  Further, the film of the present invention is a hindered phenol-based, phosphite-based, thioether-based antioxidant, benzotriazole-based, benzophenone-based, benzoate-based, hindered amine-based, cyano, as long as the effects of the present invention are not impaired. Light stabilizers such as acrylates, inorganic or organic crystal nucleating agents, molecular weight modifiers, hydrolysis inhibitors, antistatic agents, lubricants, mold release agents, plasticizers, flame retardants, flame retardant aids, foaming It may contain additives such as a colorant, a colorant, and a dispersion aid.

  The film of the present invention can be produced by a conventionally known method, and is not particularly limited. For example, the polyester resin mixture is melt-extruded in advance at a temperature of 200 ° C. to 300 ° C. and cut into pellets. Then, the pellet can be melt-extruded at a temperature of 200 ° C. or higher and 300 ° C. or lower to produce a heat-shrinkable film. Moreover, the said polyester-type resin or the said resin mixture can be melt-extruded at the temperature of 200 to 300 degreeC, and a heat-shrinkable film can also be manufactured directly.

  It does not specifically limit as an extrusion method, A T-die method, a tubular method, etc. can be used. In the case of the T-die method, after extrusion, it is rapidly cooled on a casting drum having a surface temperature of 15 ° C. or more and 80 ° C. or less to form an unstretched film having a thickness of 30 μm or more and 300 μm or less. A heated longitudinal stretching roll is used, and the roll temperature is 60 ° C. or higher and 120 ° C. or lower, preferably 60 ° C. or higher and 100 ° C. or lower, the draw ratio is 1.0 or higher and 1.3 or lower, preferably 1.0 or higher. The unstretched film is stretched under a condition of 1 time or less. Next, using a tenter, the stretching temperature is 60 ° C. or higher and 120 ° C. or lower, preferably 70 ° C. or higher and 100 ° C. or lower, the draw ratio is 1.7 times or higher and 7.0 times or lower, preferably 3.0 times or higher and 6.0 times or lower. After stretching the uniaxially stretched film under the above conditions, the film is wound by heat treatment at a temperature of 55 ° C. or higher and 100 ° C. or lower, preferably 70 ° C. or higher and 95 ° C. or lower. Here, with respect to the above stretching temperature and heat treatment temperature, the thermal shrinkage rate in the main shrinkage direction when immersed in warm water at 80 ° C. for 10 seconds and then immersed and cooled in water at 23 ° C. for 30 seconds is preferably 20% or more, preferably What is necessary is just to determine suitably so that it may become 40 to 70% of range.

  In addition, a recycled raw material can also be used as a raw material for film formation. That is, a polyester resin (A) that can be suitably used for the film of the present invention, or a mixed resin of a polyester resin (A) and a polyester resin (B) as a raw material, a sheet, a film, a fiber, a molded container, The end material generated when molding a bottle or the like, or the one obtained by once melting and pelletizing the polyester resin composition according to the present invention can be used as a raw material.

  The thickness of the film of the present invention is 10 μm or more, preferably 20 μm or more, and is 100 μm or less, preferably 80 μm or less. If the thickness of the film is 10 μm or more, there is an advantage that secondary processing is easy, and if the thickness of the film is 100 μm or less, good workability of the film can be maintained.

  The heat resistance of the film of the present invention can be evaluated by the fusing temperature (fusing start temperature). In PET bottles for hot warmers and hot benders, the labels locally attached to the bottles may be exposed to high temperatures and fused to each other. In order to prevent this, the fusion start temperature of the film of the present invention is preferably 90 ° C. or higher, more preferably 120 ° C. or higher, and further preferably 140 ° C. or higher. On the other hand, the upper limit of the fusion start temperature is 180 ° C. This is because if it exceeds 180 ° C., the PET bottle may be deformed by heat.

  Improvement of the heat resistance of the film can be achieved by increasing the content of the polyester resin (A) with respect to the whole polyester resin composition.

  When the film of the present invention is immersed in warm water at 80 ° C. for 10 seconds and then immersed and cooled in water at 23 ° C. for 30 seconds, the thermal shrinkage in the orthogonal direction is 10% or less, preferably 7% or less, more preferably It is desirable to be 5% or less. If the thermal shrinkage rate in the orthogonal direction is 10% or less in the above temperature range, the occurrence of sink marks in the label vertical direction during label molding can be suppressed, and shrinkage spots and wrinkles can be generated in the temperature range near 80 ° C. It can suppress and improve shrinkage characteristics and commercial value.

  The natural shrinkage ratio in the main shrinkage direction and the orthogonal direction of the film of the present invention is, for example, 2.0% or less, preferably 1.0% or less, more preferably 0.5% or less after 30 days storage at 30 ° C. It is desirable to be. When the natural shrinkage rate is 2.0% under the above conditions, the film of the present invention can be stably attached to a container or the like even when stored for a long period of time, and hardly causes problems in practice.

  For example, when the film of the present invention has a thickness of 50 μm measured according to JIS K7105, the haze value is preferably 10% or less, more preferably 7% or less, and 5%. More preferably, it is as follows. If the haze value is 10% or less, the transparency of the film can be obtained and a display effect can be obtained.

[Molded products, heat-shrinkable labels and containers]
The film of the present invention is excellent in the shrink finish of the film, heat resistance, tear resistance, etc., so its use is not particularly limited, but if necessary, a printing layer, a vapor deposition layer and other functional layers may be added. By forming, it can be used as various molded products such as bottles (blow bottles), trays, lunch boxes, prepared food containers, and dairy products containers. In particular, when the film of the present invention is used as a heat-shrinkable label for food containers (for example, polyethylene terephthalate (hereinafter referred to as “PET”) bottles, glass bottles, preferably PET bottles for soft drinks or foods), As a container with a label for heating because of its properties, even a more complicated shape (for example, a column with a constricted center, a square column with a center, a pentagonal column, a hexagonal column, etc.) can be adhered to the shape, A container with a beautiful label without wrinkles or avatars is obtained. The molded article and container of the present invention can be produced by using a normal molding method.

  The film of the present invention has excellent shrinkage properties, shrinkage finish, tear resistance, etc., and therefore, in addition to heat-shrinkable label materials for plastic molded products that deform when heated to high temperatures, thermal expansion coefficient and water absorption The material is very different from the heat-shrinkable film of the present invention, for example, metals, porcelain, glass, paper, polyolefin resins such as polyethylene, polypropylene, polybutene, polymethacrylate resins, polycarbonate resins, polyethylene terephthalate, poly It can be suitably used as a heat-shrinkable label material for a package (container) using at least one selected from polyester resins such as butylene terephthalate and polyamide resins as a constituent material.

  As a material constituting the plastic package in which the film of the present invention can be used, in addition to the above resin, polystyrene, rubber-modified impact-resistant polystyrene (HIPS), styrene-butyl acrylate copolymer, styrene-acrylonitrile copolymer, Styrene-maleic anhydride copolymer, acrylonitrile-butadiene-styrene copolymer (ABS), (meth) acrylic acid-butadiene-styrene copolymer (MBS), polyvinyl chloride resin, phenol resin, urea resin, melamine Examples thereof include resins, epoxy resins, unsaturated polyester resins, and silicone resins. These plastic packages may be a mixture of two or more resins or a laminate.

Next, the film, heat-shrinkable label, and container of the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.
Composition analysis and measurement of intrinsic viscosity of the polyester resin used in each example and comparative example were performed by the following methods.

(Composition analysis of polyester resin)
A polyester resin solution sample was analyzed by monitoring ¹ H with a nuclear magnetic resonance apparatus (NMR), and the dicarboxylic acid component was mol% based on the total dicarboxylic acid component, and the diol component was mol% based on the total diol component. Asked.

(Measurement of intrinsic viscosity (dl / g))
About 0.25 g of a polyester-based resin was dissolved at 110 ° C. so as to be 1.0% by mass in about 25 ml of a mixed solvent of phenol / tetrachloroethane (mass ratio 1/1), and then cooled to 30 ° C. It measured at 30 degreeC with the automatic solution viscometer (Cortech Co., Ltd. product "2CH type DJ504").

The heat-shrinkable polyester film produced in each example and comparative example was evaluated by the following method.
(Evaluation methods)
(1) Heat Shrinkage The film obtained in each Example and Comparative Example was cut to a size of 150 mm in the stretching direction (main shrinkage direction) and 10 mm in a direction perpendicular to the film to prepare a sample. Marks with 100 mm intervals in the drawing direction of the sample, dipped in a warm water bath at 80 ° C. for 10 seconds, and then dipped in cold water at 23 ° C. for 30 seconds were measured. The 80 ° C. shrinkage was calculated according to 1).
“80 ° C. Shrinkage” (%) = 100 × (100−D) / 100 (1)

(2) Shrinkage finish The film obtained in each Example and Comparative Example was formed into a cylindrical shape so that the stretching direction was the circumferential direction, and the film was covered with a 500 mL PET bottle filled with water, and adjusted to 80 to 90 ° C. The shrinkage state after passing through the steam shrink tunnel for 5 seconds was observed and judged according to the following criteria.
○: Beautiful appearance without shrinkage unevenness and wrinkles △: Appearance with slight shrinkage unevenness and wrinkles ×: Appearance with significant shrinkage unevenness and wrinkles

(3) Elongation at break Ten films obtained by cutting the films obtained in each Example and Comparative Example into a strip shape having a length of 15 mm in the stretching direction (main shrinkage direction) and a length of 100 mm in the direction orthogonal to the stretching direction. The test piece was subjected to a tensile test in a direction orthogonal to the stretching direction at a distance between chucks of 20 mm, a temperature of 23 ° C., and a tensile speed of 200 mm / min.

(4) Breaking with time The film obtained in each Example and Comparative Example was cut into A4 size and darkened for 2 weeks under conditions of 45 ° C. and 30% RH in a constant temperature and humidity chamber PR-2KT manufactured by Tabyes Tech. Stored. Thereafter, 10 test pieces cut into a strip shape having a length of 15 mm in the stretching direction (main shrinkage direction) and a length of 100 mm in the direction perpendicular to the stretching direction from the stored A4 size sample were orthogonal to the stretching direction. The tensile test was conducted at a distance between chucks of 20 mm, a temperature of 23 ° C., and a tensile speed of 200 mm / min, and the number of lines that grew 100% or more without breaking was counted. 80% or more was accepted.

(5) Time-lapse fracture after ink application The film obtained in each Example and Comparative Example was cut into A4 size, NSV silver ink made by Osaka Ink Co., Ltd. on one side, and medium ink made by Osaka Ink Co., Ltd. on the other side. Made by Seiki Co., Ltd .: applied once using a test bar coater (model 4), and then kept in a dark place at 45 ° C., 30% RH for 3 days in a thermo-hygrostat made by Tabaystec: PR-2KT . Thereafter, 10 test pieces cut into a strip shape having a length of 15 mm in the stretching direction (main shrinkage direction) and a length of 100 mm in the direction perpendicular to the stretching direction from the stored A4 size sample were orthogonal to the stretching direction. The tensile test was conducted at a distance between chucks of 20 mm, a temperature of 23 ° C., and a tensile speed of 200 mm / min. The number of the wires that grew 100% or more without breaking was counted, and the ratio of the number of the ten wires out of 10 was expressed in%. 80% or more was accepted.

(6) Fusion start temperature The film was cut into a length of 60 mm in the stretching direction (main shrinkage direction) and a length of 300 mm in the direction perpendicular to the stretching direction, and the two films were stacked to form “TP-” manufactured by Tester Sangyo Co., Ltd. 701-A heat seal tester ". Set the temperature in the range of 70-180 ° C in 5 ° C increments, pressurize each pressure at 0.1 MPa, pressurize for 1 minute, confirm the presence or absence of fusion, and the fusion start temperature that is the lowest temperature at which fusion occurs Asked.

(7) Breakability at the time of printing The film was cut into a length of 500 mm in the stretching direction (main shrinkage direction) and a length of 1000 m in the direction orthogonal to the stretching direction, NSV silver ink manufactured by Osaka Ink Co., Ltd. on one side of the film, Solid printing of NSV medium ink manufactured by Osaka Ink Co., Ltd. was performed at a speed of 150 m / min. In the film of 1000 m, no break occurred, ○, one occurred, Δ, two or more occurred.

Next, the raw material polyester resin used in each example and comparative example will be described below.
(1) Polyester resin 1 (PET1)
Polyester resin 1 was produced by the method of Production Example 1 described below. As a result of performing composition analysis on the polyester resin 1 by the above-described method, the dicarboxylic acid component is 1,4-cyclohexanedicarboxylic acid (hereinafter abbreviated as “CHDA”), and the diol component is 1,4- It was a polyester resin that was cyclohexanedimethanol (hereinafter abbreviated as “CHDM”). Moreover, it was 0.98 dl / g as a result of measuring the intrinsic viscosity of this polyester-type resin 1 with the said method.

(Production Example 1)
Equipped with a stirrer, distilling tube, heating device, pressure gauge, thermometer, and decompression device, and a stainless steel reactor with a capacity of 100 liters, CHDA (trans isomer: cis cis ratio is 96: 4) 101.5 mass Part, CHDM (trans isomer: cis cis ratio: 69:31) 87 parts by mass and tetra-n-butyltitanium 6 mass% butanol solution 0.005 parts by mass were charged, and the inside of the reactor was replaced with nitrogen gas. . While sealing the inside of the reactor with nitrogen gas, the internal temperature was increased to 150 ° C. in 30 minutes, and further increased from 150 ° C. to 200 ° C. over 1 hour. Next, after carrying out the esterification reaction by holding at a temperature of 200 ° C. for 1 hour, the polycondensation reaction is carried out while gradually raising the pressure in the reactor while increasing the temperature from 200 ° C. to 250 ° C. over 45 minutes. It was. The reactor internal pressure was 0.1 kPa and the reaction temperature was 250 ° C. and maintained for 3.3 hours to complete the polycondensation reaction. After completion of the polycondensation reaction, the obtained polyester-based resin was extracted in a strand shape into water, cut and pelletized. Thereafter, the same operation was repeated 7 times, and the obtained pellets were stirred with a blender to obtain 2.2 tons of polyester resin 1 (PET1).

(2) Polyester resin 2 (PET2)
“EMBRACE Copolyester” manufactured by Eastman Chemical Co. was used. As a result of composition analysis of the polyester resin 2 (PET2) by the above-described method, the dicarboxylic acid component is terephthalic acid (hereinafter abbreviated as “TPA”), and the diol component is ethylene glycol (hereinafter “EG”). Abbreviated as “.”) Is 72 mol% based on the total diol, CHDM is 20 mol% based on the total diol, and diethylene glycol (hereinafter abbreviated as “DEG”) is 8 mol% based on the total diol. It was a polyester resin. Moreover, it was 0.83 dl / g as a result of measuring the intrinsic viscosity of this PET2 by the said method.

(3) Polyester resin 3 (PET3)
“NOVAPEX: GS400” manufactured by Mitsubishi Chemical Corporation was used as polyester resin 3 (PET3). As a result of analyzing the composition of this PET3 by the above method, the dicarboxylic acid component was TPA, and the diol component was 98 mol% EG and 2 mol% DEG in the total diol. Moreover, it was 0.71 dl / g as a result of measuring the intrinsic viscosity of PET3 by the said method.

(4) Polyester resin 4 (PET4)
“NOVAPEX PS600” manufactured by Mitsubishi Chemical Corporation was used as polyester resin 4 (PET4). As a result of analyzing the composition of this PET4 by the above-described method, the dicarboxylic acid component was 70 mol% in total dicarboxylic acid, 30 mol% was isophthalic acid, and the diol component was 98 mol% in all diols. Was EG and 2 mol% was DEG. Moreover, it was 0.72 dl / g as a result of measuring the intrinsic viscosity of PET4 by the said method.

Example 1
The polyester resin (A) is blended so that the polyester resin PET1 is 5% by mass, and the polyester resin (B) is 95% by mass, and then the polyester resin (A) and the polyester resin are blended. To 100 parts by mass of the resin (B), 0.1 parts by mass of synthetic silica (“Cycilia 320” manufactured by Fuji Silysia Chemical Co., Ltd.) as inorganic fine particles was added and mixed, and then the width was measured using a “TEM 58 mm” extruder manufactured by Toshiba Machine. A sheet having a width of 250 mm and a thickness of 0.25 mm was obtained from a 300 mm T die die while being pulled at 270 ° C. on a cooling roll with a time discharge of 200 kg while pulling a vacuum vent. Thereafter, the sheet is stretched 4.5 times in the vertical direction with respect to the casting extrusion direction at a stretching temperature of 84 ° C. and continuously heat-treated at 92 ° C. with a continuous transverse stretching machine (tenter). A heat-shrinkable film having a thickness of 50 μm and a width of 1100 mm was obtained. Thereafter, the heat-shrinkable film was evaluated at a film central portion of 500 mm. The results are shown in Table 1.

(Examples 2-6 and Comparative Examples 1-4)
Example except that polyester resin (A) or polyester resins (A) and (B) were blended in the blending amounts shown in Table 1, and the stretching temperature and heat treatment temperature were changed to the temperatures shown in Table 1, respectively. A heat-shrinkable film was prepared in the same manner as in 1. The obtained film was evaluated in the same manner as in Example 1. The results are shown in Table 1.

From Table 1, the films of Examples 1 to 6 did not break at all during printing, and the appearance after processing was also beautiful. On the other hand, in the films of Comparative Examples 1 to 4, breakage occurred during printing or appearance defects occurred after processing.
From this, it can be seen that the film of the present invention is a heat-shrinkable film excellent in breakage resistance during processing and printing, and excellent in shrink finish and productivity.

  Since the film of the present invention is a heat-shrinkable film having excellent rupture resistance during processing and printing, and excellent in shrinkage finish and productivity, various heat-shrinkable labels, particularly heat-shrinkable labels for heating And a container equipped with the label.

Claims (5)

A heat-shrinkable polyester film obtained from a polyester resin composition containing a polyester resin (A) obtained from an alicyclic dicarboxylic acid component and an alicyclic diol component;
The content of the polyester resin (A) with respect to the polyester resin composition is 5% by mass or more,
After being immersed in warm water at 80 ° C. for 10 seconds and then immersed and cooled in water at 23 ° C. for 30 seconds, the heat shrinkage rate in the main shrinkage direction is 20% or more,
A plurality of strip-shaped test pieces having a length in the main shrinkage direction of 15 mm and a length in the direction perpendicular to the main shrinkage direction of 100 mm are cut out, and in the direction perpendicular to the main shrinkage direction, the distance between chucks is 20 mm, the temperature is 23 ° C., The elongation at break when a tensile test is performed at a tensile speed of 200 mm / min is 400% or more in all test pieces,
In addition, after being stored for 2 weeks in an atmosphere at a temperature of 45 ° C. and a relative humidity of 30%, a plurality of test pieces cut into the same strip shape as described above have a breaking elongation of 100 when subjected to a tensile test under the same conditions as described above. % Heat-shrinkable polyester film, wherein the number of test pieces is 80% or more of the total number of test pieces. The polyester resin composition comprises the polyester resin (A) and a polyester resin (B) containing 65 mol% or more and 97 mol% or less of a terephthalic acid-ethylene glycol unit,
The heat-shrinkable polyester film according to claim 1, wherein a mixing ratio of the polyester resin (A) and the polyester resin (B) is A / B = 5/95 to 99/1 in mass%. .   The heat-shrinkable polyester film according to claim 1 or 2, wherein the alicyclic dicarboxylic acid component is 1,4-cyclohexanedicarboxylic acid and the alicyclic diol component is 1,4-cyclohexanedimethanol.   A heat-shrinkable label using the heat-shrinkable polyester film according to any one of claims 1 to 3 as a base material.   A container equipped with the heat-shrinkable label according to claim 4.