JP2005171181A - Polyester heat-shrinkable film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester heat-shrinkable film which exhibits good heat-shrinking characteristics, good shrinking finish and an excellent perforation-cutting property. <P>SOLUTION: The polyester heat-shrinkable film is obtained by molding a resin composition comprising 100 pts. wt. of a polyester resin comprising a dicarboxylic acid component, a diol component and a polyalkylene glycol component and 5-40 pts. wt. of an aromatic polycarbonate resin, where the dicarboxylic acid component constituting the polyester resin comprises 10-90 wt% of an aromatic dicarboxylic acid component and 90-10 wt% of an aliphatic dicarboxylic acid component, the content of the polyalkylene glycol component is 1-30 wt% based on the whole polyester resin, and the ratio of the tensile modulus in the direction rectangularly crossing the main shrinking direction of the film to the tensile modulus in the main shrinking direction is 0.30-0.70. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a polyester-based heat-shrinkable film. Specifically, after heat shrinkage, it does not cause defects such as shrinkage whitening, shrinkage spots, wrinkles, and distortion, and can be shrunk using a general steam or hot air shrink tunnel. Furthermore, the present invention relates to a polyester heat-shrinkable film that can be easily cut along perforations applied to the film and can be easily peeled off, and is preferably used for shrinkage labels, food packaging, and the like.

Conventionally, stretch films made of polyvinyl chloride or polystyrene have been mainly used as shrink labels used for glass bottles and polyethylene terephthalate bottles (pet bottles) and shrink films for food packaging. On the other hand, in recent years, a heat-shrinkable film using a polyester resin excellent in safety and hygiene and chemical resistance has been demanded, and the use of a stretched film made of a polyester resin is increasing.
However, currently used polyester-based heat-shrinkable films are excellent in rigidity, but the perforation-opening properties are not cut along the perforations when compared with heat-shrinkable films made of polyvinyl chloride or polystyrene. However, there is a problem that tears propagate in a direction perpendicular to the perforation, which is cut into a so-called “apple peel” and is difficult to open.

Therefore, perforation opening formed in a polyester film containing 0.1 to 20% by weight of a polyester elastomer in an aromatic polyester and further containing a polyalkylene glycol as a low melting point soft polymer segment constituent component. An improved heat-shrinkable polyester film has been proposed (see, for example, Patent Document 1).
However, in a system containing a large amount of polyester elastomer in aromatic polyester, the compatibility is poor and transparency is lowered. Further, the perforation openability is not always sufficient.

JP 2000-169601 A

  An object of the present invention is to provide a polyester heat-shrinkable film having good shrinkage characteristics, good shrinkage finish and excellent perforation openability under such circumstances.

  As a result of intensive studies to solve the above problems, the present inventors have molded a polyester resin comprising a dicarboxylic acid component, a diol component and a polyalkylene glycol component, and a resin composition containing an aromatic polycarbonate resin. A polyester-based heat-shrinkable film, wherein the dicarboxylic acid component constituting the polyester resin is an aromatic dicarboxylic acid component and an alicyclic dicarboxylic acid component, and the tensile elastic modulus in the direction perpendicular to the main shrinkage direction of the film It has been found that a polyester heat-shrinkable film characterized in that the ratio of the tensile elastic modulus in the main shrinkage direction is 0.30 to 0.70 can solve the above-mentioned problems.

That is, the present invention is (1) a polyester system obtained by molding a resin composition comprising 100 parts by weight of a polyester resin comprising a dicarboxylic acid component, a diol component and a polyalkylene glycol component and 5 to 40 parts by weight of an aromatic polycarbonate resin. A heat-shrinkable film, wherein the dicarboxylic acid component constituting the polyester resin comprises 10 to 90% by weight of an aromatic dicarboxylic acid component and 90 to 10% by weight of an alicyclic dicarboxylic acid component, and contains a polyalkylene glycol The amount is 1 to 30% by weight based on the total amount of the polyester resin, and the ratio of the tensile elastic modulus in the direction perpendicular to the main shrinkage direction of the film to the tensile elastic modulus in the main shrinkage direction is 0.30 to 0.70. Polyester-based heat-shrinkable film,
(2) A direction in which the maximum shrinkage in the main shrinkage direction is 30% or more after being immersed in warm water at 80 ° C. for 10 seconds and then immersed in water at 23 ° C. for 30 seconds and orthogonal to the main shrinkage direction The polyester-based heat-shrinkable film according to (1), wherein the maximum shrinkage is 5% or less,
(3) The polyester-based heat-shrinkable film according to (1) or (2), wherein the alicyclic dicarboxylic acid component constituting the polyester resin is a cyclohexanedicarboxylic acid component,
(4) The polyester-based heat-shrinkable film according to any one of (1) to (3), wherein the number average molecular weight of the polyalkylene glycol component is 500 to 6000,
(5) The polyester-based heat-shrinkable film according to any one of (1) to (4), wherein the polyalkylene glycol component is derived from polytetramethylene glycol.
(6) The polyester heat-shrinkable film according to any one of the above (1) to (5), wherein the diol component constituting the polyester resin includes an alicyclic diol component,
(7) The polyester heat-shrinkable film according to (6), wherein the content of the alicyclic diol component constituting the polyester resin is 10 to 90% by weight with respect to the total amount of the diol component,
(8) The polyester heat-shrinkable film according to (6) or (7), wherein the alicyclic diol component constituting the polyester resin is derived from cyclohexanedimethanol,
Is to provide.

  The polyester heat-shrinkable film of the present invention has good shrinkage properties and excellent perforation opening.

  The polyester heat-shrinkable film of the present invention is formed by molding a resin composition containing 100 parts by weight of a polyester resin composed of a dicarboxylic acid component, a diol component and a polyalkylene glycol component and 5 to 40 parts by weight of an aromatic polycarbonate resin. A polyester-based heat-shrinkable film, wherein the dicarboxylic acid component constituting the polyester resin comprises 10 to 90% by weight of an aromatic dicarboxylic acid component and 90 to 10% by weight of an alicyclic dicarboxylic acid component. The content of glycol is 1 to 30% by weight based on the total amount of the polyester resin, and the ratio of the tensile elastic modulus in the direction orthogonal to the main shrinkage direction of the film to the tensile elastic modulus in the main shrinkage direction is 0.30 to 0.00. 70.

The aromatic dicarboxylic acid constituting the aromatic dicarboxylic acid component according to the present invention is not particularly limited, but terephthalic acid, isophthalic acid, orthophthalic acid, phenylenedioxydiacetic acid, 4,4′-diphenyldicarboxylic acid, 4, 4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid or ester-forming derivatives thereof Among them, terephthalic acid or an ester-forming derivative thereof is particularly preferable.
The content of the aromatic dicarboxylic acid component is in the range of 10 to 90% by weight as described above. If it is less than 10% by weight, there is an inconvenience that the heat resistance is lowered.
The content of the aromatic dicarboxylic acid component is preferably 20% by weight or more, more preferably 30% by weight or more, preferably 85% by weight or less, more preferably 80% by weight or less.

The alicyclic dicarboxylic acid compound for constituting the alicyclic dicarboxylic acid component according to the present invention is not particularly limited. For example, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid or ester-forming derivatives thereof. Etc. are preferable. Among these, 1,4-cyclohexanedicarboxylic acid or an ester-forming derivative thereof is particularly preferable from the viewpoints of shrinkability and heat resistance.
The content of the alicyclic dicarboxylic acid component is in the range of 90 to 10% by weight as described above. If it is less than 10% by weight, the shrinkage properties and shrinkage finish will be poor, while if it exceeds 90% by weight, the heat resistance will deteriorate.
The content of the alicyclic dicarboxylic acid component is preferably 15% by weight or more, more preferably 20% by weight or more, preferably 80% by weight or less, more preferably 70% by weight or less.
When the alicyclic dicarboxylic acid component is reacted with a dicarboxylic acid compound and a diol compound to obtain a polyester resin, a part of the alicyclic dicarboxylic acid compound is mixed in the dicarboxylic acid compound to obtain a single copolymer. It can be contained as a coalescence. In addition, a polyester resin obtained by reacting an alicyclic dicarboxylic acid compound and a diol compound is synthesized, and a polyester obtained by reacting a diol compound with a dicarboxylic acid compound such as an aromatic dicarboxylic acid other than the alicyclic dicarboxylic acid compound. It can also be contained by mixing with a resin.

Next, as the diol compound constituting the diol component of the polyester resin according to the present invention, various diol compounds can be used, and examples thereof include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1 , 3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 2,2-dimethyl-1,3 -Propanediol, diethylene glycol and the like are exemplified, and among these, ethylene glycol is preferably used.
Moreover, it is preferable that the diol component which comprises the said polyester resin contains an alicyclic diol component. Specific examples of the alicyclic diol that can be used here include 1,1-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, Examples include 2-cyclohexanediol and 1,4-cyclohexanediol. Among these, 1,4-cyclohexanedimethanol is particularly preferably used. Further, the trans / cis isomer ratio of 1,4-cyclohexanedimethanol is preferably 50 mol% or more from the viewpoint of heat resistance.
The diol component does not include a polyalkylene glycol component.

The content of the alicyclic diol component constituting the polyester resin is preferably in the range of 10 to 90% by weight with respect to the total amount of the diol component. When the content of the alicyclic diol component is 10% by weight or more, the shrinkage characteristics and shrinkage finish are good, and when it is 90% by weight or less, the heat resistance is excellent. From these viewpoints, it is further preferably in the range of 20 to 80% by weight.
When the alicyclic diol component is obtained by reacting a dicarboxylic acid compound and a diol compound to obtain a polyester resin, a part of the alicyclic diol compound is mixed in the diol compound to form a single copolymer. It can be included. In addition, a polyester resin obtained by reacting a dicarboxylic acid compound and an alicyclic diol compound is synthesized and mixed with a polyester resin obtained by reacting a dicarboxylic acid compound and a diol compound such as ethylene glycol other than the alicyclic diol compound. It can also be made to contain.

Next, in the present invention, it is essential that the polyalkylene glycol component is contained as a constituent component of the polyester resin, and the content thereof is in the range of 1 to 30% by weight with respect to the total amount of the polyester resin.
Specific examples of the polyalkylene glycol constituting the polyalkylene glycol component include polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene glycol, polyhexamethylene glycol, block or random copolymer of ethylene oxide and propylene oxide. Etc. These may be used alone or in combination of two or more. Among these, polyethylene glycol and polytetramethylene glycol are preferable, and polytetramethylene glycol is particularly preferable from the viewpoint of the polymerizability of the polyester resin and the shrink finish of the resulting heat-shrinkable film.

The number average molecular weight of the polyalkylene glycol is preferably in the range of 500 to 6,000, more preferably in the range of 500 to 2500, particularly preferably in the range of 500 to 2,300, most preferably 600 to 2,000. Range. When the number average molecular weight is 500 or more, the tensile elasticity modulus of the obtained polyester heat-shrinkable film does not become too high. On the other hand, when the number-average molecular weight is 6,000 or less, the resulting polyester heat-shrinkable film is transparent. Property is improved.
In addition, polyalkylene glycols having different number average molecular weights can be used in combination. When a plurality of types are used in combination, the number average molecular weight in a uniformly mixed state is preferably within the above range. The number average molecular weight of the polyalkylene glycol can be measured by a general method such as gel permeation chromatography.

Moreover, content of the said polyalkylene glycol component is the range of 1-30 weight% with respect to the polyester resin whole quantity. If it is less than 1% by weight, the resulting polyester-based heat-shrinkable film has a disadvantage that the tensile elastic modulus becomes too high. On the other hand, if it exceeds 30% by weight, the transparency of the resulting polyester-based heat-shrinkable film decreases. At the same time, there is a problem that it is difficult to produce a polyester resin. From the above viewpoint, the content of the polyalkylene glycol component is preferably 1.5% by weight or more, more preferably 2% by weight or more, more preferably 20% by weight or less, particularly 10% by weight based on the total amount of the polyester resin. % By weight or less is preferred.
The polyalkylene glycol can be contained as a single copolymer by partially mixing the polyalkylene glycol together with the diol compound when the polyester resin is obtained by reacting the dicarboxylic acid compound and the diol compound. . Alternatively, an oligomer having a low polymerization degree is produced from a dicarboxylic acid compound and a diol compound, and the polyalkylene glycol can be contained in the polyester resin by polycondensation of the oligomer with the polyalkylene glycol.

Furthermore, in the polyester resin according to the present invention, a dicarboxylic acid compound other than the above-mentioned dicarboxylic acid compound may be copolymerized as long as the effects of the present invention are not impaired. Examples of such dicarboxylic acids include aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, azelaic acid, and sebacic acid.
In addition, the polyester resin according to the present invention is, for example, 4,4′-dihydroxybiphenyl, 2,2-bis (4′-hydroxyphenyl) propane, 2,2- Aromatic diols such as bis (4′-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfone, glycolic acid, p-hydroxybenzoic acid, p- Monofunctional components such as hydroxycarboxylic acids such as β-hydroxyethoxybenzoic acid and alkoxycarboxylic acids, stearic acid, stearyl alcohol, benzyl alcohol, benzoic acid, t-butylbenzoic acid, benzoylbenzoic acid, tricarballylic acid, hexanetricarboxylic acid , Trimellitic acid, trimesic acid, pyromellitic acid, Trifunctional or higher functional groups such as zophenone tetracarboxylic acid, naphthalene tetracarboxylic acid, 1,2,6-hexanetriol, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, sorbitol, dipentaerythritol, polyglycerol, etc. A polyfunctional component may be copolymerized.

  The polyester resin according to the present invention can be produced by a batch method or a continuous method by a conventional method for producing a polyester resin, that is, a direct polymerization method or a transesterification method. Here, the aforementioned arbitrary copolymerization component can be added at any stage of the polycondensation reaction process. It is also possible to produce a polyester resin by producing an oligomer having a low degree of polymerization from a dicarboxylic acid compound and a diol compound and polycondensing this with any of the aforementioned copolymerization components.

In the above production method, the esterification reaction is performed in the presence of 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 is performed in the presence of 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.
The polycondensation reaction is carried out 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, The reaction is performed in the presence of 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.
Of these polycondensation catalysts, at least one selected from tetrabutoxy titanate, diantimony trioxide, and germanium dioxide is preferably used.
Further, an antifoaming agent such as silicone oil can be added to promote defoaming in the polycondensation process.

  In the polyester resin according to the present invention, the intrinsic viscosity measured at 30 ° C. in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio of 1: 1) is usually 0.4 to 1.5 dl. / G is preferable. When the intrinsic viscosity is 0.4 dl / g or more, sufficient mechanical properties of the heat-shrinkable film can be obtained, and when it is less than 1.5 dl / g, the heat-shrinkable film can be easily formed. From these viewpoints, the intrinsic viscosity under the above conditions is more preferably in the range of 0.6 to 1.2 dl / g.

The polyester heat-shrinkable film of the present invention is formed by molding a resin composition containing 5 to 40 parts by weight of an aromatic polycarbonate resin with respect to 100 parts by weight of the polyester resin. When the blending amount of the aromatic polycarbonate resin is 5 parts by weight or more, the heat resistance is excellent, and when it is 40 parts by weight or less, the shrinkage characteristics and the shrink finish are good.
The blending amount of the aromatic polycarbonate resin is preferably 10% by weight or more, and preferably 35% by weight or less.
Although it does not specifically limit as a kind of aromatic polycarbonate resin, From viewpoints, such as availability, a bisphenol type polycarbonate is preferable.
Moreover, the resin composition containing the polyester resin and the aromatic polycarbonate resin according to the present invention is obtained by mixing the polyester resin and the aromatic polycarbonate resin, or by producing respective oligomers and polycondensing them. be able to.

The resin composition preferably contains inorganic and / or organic fine particles from the viewpoint of providing blocking resistance and slipperiness when formed into a heat-shrinkable film. The content of the fine particles is preferably in the range of 0.005 to 1% by weight, more preferably in the range of 0.01 to 0.6% by weight, particularly 0.02 to 0.5% with respect to the entire film. It is preferably in the range of% by weight.
There are no particular restrictions on what constitutes the inorganic fine particles, and examples thereof include silica, alumina, titania, kaolin, clay, calcium carbonate, calcium phosphate, lithium fluoride, and the like, and phosphorus compounds used at the time of polyester polymerization. Fine particles originating from the catalyst may be used. The organic fine particles are not particularly limited, and examples thereof include carbon black and various crosslinked polymers.
The average particle diameter of these fine particles is preferably in the range of 0.5 to 10 μm, more preferably in the range of 1 to 8 μm, particularly in the range of 1 to 5 μm, from the viewpoint of the above-described effects. The average particle diameter means 50% volume average particle diameter (d50) measured by a laser diffraction method.
Moreover, it does not specifically limit as a mixing method of this microparticles | fine-particles, It can also add in the polymerization process of a polyester resin, and can also mix in the manufacture process of a resin composition, and the formation process of a heat-shrinkable film.

The resin composition according to the present invention may be mixed with 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 resin composition is a hindered phenol, phosphite, thioether antioxidant, benzotriazole, benzophenone, benzoate, hindered amine, cyanoacrylate, or other light stabilizer, inorganic or Addition of organic crystal nucleating agent, molecular weight modifier, hydrolysis resistance, antistatic agent, lubricant, mold release agent, plasticizer, flame retardant, flame retardant auxiliary, foaming agent, colorant, dispersion aid, etc. An agent may be contained.

The polyester heat-shrinkable film of the present invention can be produced by a conventionally known method, and is not particularly limited. For example, the resin composition as a raw material is melt-extruded and cut at a temperature of 200 to 300 ° C. in advance. The pellet-shaped resin composition can be melt-extruded at a temperature of 200 to 300 ° C. to produce a heat-shrinkable film. Moreover, a heat-shrinkable film can be directly produced by melt-extruding the polyester resin and the polycarbonate resin at a temperature of 200 to 300 ° C. 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 to 80 ° C. to form an unstretched film having a thickness of 30 to 300 μm. And an unstretched film is extended | stretched on the conditions of roll temperature 60-120 degreeC and draw ratio 1.0-1.3 times, Preferably 1.0-1.1 times using a heating longitudinally-stretching roll. Next, using a tenter, the uniaxially stretched film is stretched under the conditions of a stretching temperature of 60 to 120 ° C. and a stretching ratio of 1.7 to 7.0, and then heat-treated at a temperature of 55 to 100 ° C. and wound up. Here, with respect to the stretching temperature, the shrinkage in the main shrinkage direction when immersed in warm water of 80 ° C. for 10 seconds and then immersed and cooled in water of 23 ° C. for 30 seconds is 30% or more, preferably 50% or more. What is necessary is just to decide suitably so that it may become.
In addition, a recycled raw material can also be used as a raw material for film formation. That is, the resin composition according to the present invention is used as a raw material, the mill ends generated when molding sheets, films, fibers, molded containers, bottles, etc., or the resin composition according to the present invention is once melted into pellets What was made can also be used as a raw material.

The thickness of the polyester heat-shrinkable film of the present invention is preferably in the range of 10 to 100 μm. When the thickness of the polyester heat-shrinkable film is 10 μm or more, there is an advantage that secondary processing is easy, and a film exceeding 100 μm tends to be inferior in workability.
The polyester heat-shrinkable film of the present invention is characterized in that the ratio of the tensile elastic modulus in the direction orthogonal to the main shrinkage direction of the film and the tensile elastic modulus in the main shrinkage direction is 0.3 to 0.7. Here, the tensile modulus of elasticity of the polyester resin film is a rectangular test piece (length 70 mm, width 5 mm) in which the main shrinkage direction of the film is parallel to the long side, and the direction perpendicular to the main shrinkage direction of the film is parallel to the long side. A rectangular test piece (length 70 mm, width 5 mm) was used, the distance between chucks was 50 mm, and the tensile tester was installed in a thermostatic chamber at 23 ° C. A stress-strain curve in the length direction is obtained at a tensile test speed of 5 mm / min, and the stress difference between two points on the straight line divided by the initial cross-sectional area in the straight part immediately after the start of the test is the same as the strain difference between the two points The value divided by is defined as the tensile modulus.
When the ratio of the tensile elastic modulus in the direction perpendicular to the main shrinkage direction and the tensile elastic modulus in the main shrinkage direction is in the range of 0.3 to 0.7, the film formability and perforation opening properties are excellent. From the above viewpoint, the ratio of the tensile elastic modulus is preferably in the range of 0.4 to 0.65.

In addition, the polyester-based heat-shrinkable film of the present invention has a maximum shrinkage in the main shrinkage direction of 30% or more after being immersed in 80 ° C. warm water for 10 seconds and then immersed in 23 ° C. water for 30 seconds. And it is preferable that the maximum shrinkage rate in the direction orthogonal to the main shrinkage direction is 5% or less. When the maximum shrinkage rate in the main shrinkage direction is 30% or more, sufficient shrinkage characteristics can be obtained and the shrinkage finish is good. On the other hand, the maximum shrinkage rate in the direction orthogonal to the main shrinkage direction is 5% or less. In addition, there is an advantage that the so-called “longitudinal shrinkage” that damages the appearance due to excessive shrinkage in the vertical direction does not occur. From the above viewpoint, the maximum shrinkage rate in the main shrinkage direction is preferably in the range of 30 to 70%, and the maximum shrinkage rate in the direction orthogonal to the main shrinkage direction is further preferably 3% or less.
Here, the heat shrinkage rate is the value obtained by subtracting the length after shrinkage from the length before shrinkage after measuring the longitudinal and transverse dimensions of the film after heat shrinkage under the above conditions. The thing divided by.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not restrict | limited at all by 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), with respect to the dicarboxylic acid component, mol% relative to the total dicarboxylic acid component, and with respect to the diol component, mol% relative to the total diol component, Furthermore, content (weight%) with respect to the polyester resin of a polyalkylene glycol component was calculated | required.
(Measurement of intrinsic viscosity (dl / g))
About 0.25 g of polyester resin is dissolved at about 110 ° C. in about 25 ml of a mixed solvent of phenol / tetrachloroethane (weight ratio 1/1) at 110 ° C. and then cooled to 30 ° C. It measured at 30 degreeC with the solution viscometer (Chuo Rika "2CH type DJ504").

The polyester heat-shrinkable film produced in each example and comparative example was evaluated by the following method.
(Evaluation methods)
(1) Tensile modulus ratio The film obtained in each example or comparative example is a rectangular test piece having a main shrinkage direction (hereinafter referred to as “TD”) of 70 mm in length and 5 mm in width parallel to the long side, In addition, a rectangular test piece having a length of 70 mm and a width of 5 mm, in which the direction perpendicular to the main shrinkage direction of the film (hereinafter referred to as “MD”) is parallel to the long side, was sampled, and the constant temperature at a chuck distance of 50 mm and 23 ° C. It measured with the tensile tester installed in the room. A stress-strain curve in the length direction is obtained at a tensile test speed of 5 mm / min, and the stress difference between the two points on the straight line divided by the initial cross-sectional area in the straight line portion immediately after the start of the test is the same as the strain difference between the two points. The tensile modulus was obtained by dividing by Next, the tensile elastic modulus ratio was determined by dividing the tensile elastic modulus in the MD direction by the tensile elastic modulus in the TD direction.
(2) Shrinkage rate The film obtained in each Example or Comparative Example was cut into a 10 cm × 10 cm square, immersed in 80 ° C. warm water for 10 seconds, and immersed and cooled in 23 ° C. water for 30 seconds. The longitudinal and lateral dimensions of the film were measured, and the value obtained by subtracting the length after shrinkage from the length before shrinkage was divided by the length before shrinkage to determine the shrinkage rate. The direction with the largest shrinkage rate was defined as the main shrinkage direction (TD).
(3) Perforation openability A perforated label for opening was produced from the film obtained in each example or comparative example in a cylindrical shape at a pitch of 0.7 × 0.7 mm. Using a steam tunnel (“SKT-3000” manufactured by Keiyu System Co., Ltd.), a 280 mL PET bottle filled with water was covered with a label from the bottom to the neck. Then, the bottle is refrigerated to 5 ° C., and the bottle immediately after taking out from the refrigerator is torn the perforation of the label with a fingertip, and at that time, it is visually observed whether cutting has occurred in the middle of the perforation. did. The number of measurements was set to 5 and the determination was made according to the following criteria.
◎ Cut to the bottom of the bottle along the perforation without problems.
〇 Cut along the perforation while feeling resistance on the way to the bottom of the bottle.
△ It cuts to some extent along the perforation, but before it reached the bottom, it became peeled.
× Almost no perforation along the perforation, and the apple peeled.

(Raw material polyester resin)
The polyester resin used as a raw material in each example and comparative example will be described in detail below.
(1) Polyester resin 1 (PET1)
“EASTAR PETG Copolyester 6763” manufactured by Eastman Chemical Co. was used. As a result of composition analysis of the polyester resin by the above-described method, the dicarboxylic acid component was terephthalic acid (hereinafter abbreviated as “TPA”), and the diol component was abbreviated as ethylene glycol (hereinafter abbreviated as “EG”). The polyester resin was 68 mol% with respect to the total diol and 1,4-cyclohexanedimethanol (hereinafter abbreviated as “CHDM”) was 32 mol% with respect to the total diol. Moreover, it was 0.78 dl / g as a result of measuring the intrinsic viscosity of this polyester resin by the said method.

(2) Polyester resin 2 (PET2)
A polyester resin was produced by the method of Production Example 1 described below. As a result of composition analysis of the polyester resin by the method described above, the dicarboxylic acid component was 1,4-cyclohexanedicarboxylic acid (hereinafter abbreviated as “CHDA”), the diol component was CHDM, Tetramethylene glycol (hereinafter abbreviated as PTMG) was a polyester resin copolymerized with 10 parts by weight with respect to 100 parts by weight of the polyester resin excluding the PTMG component. In addition, the intrinsic viscosity of the polyester resin was measured by the above method and found to be 1.28 dl / g.
Production Example 1
In a reaction vessel equipped with a stirrer and a batch polymerization apparatus equipped with a pelletizing device, 18.4 kg (107 mol) of CHDA having a trans isomer content of 98%, 15.6 kg (108 mol) of CHDM having a trans isomer content of 70%, and 870 ml of a 6% butanol solution of tetra-n-butyl titanate was charged, heated to 150 ° C. under a nitrogen flow, and then heated to 200 ° C. Thereafter, the mixture was kept at 200 ° C. for 1 hour to carry out an esterification reaction. Next, 5 kg of PTMG having a number average molecular weight of 1,000 was added to the reaction vessel, and a polycondensation reaction was performed while gradually raising the pressure from 200 ° C. to 250 ° C. while gradually reducing the pressure in the reactor. After the polycondensation for 2.2 hours at a reaction tank pressure of 0.1 kPa and a reaction temperature of 250 ° C., the obtained polyester resin was extracted into water as a strand and then cut into a pellet.

(3) Polyester resin 3 (PET3)
A polyester resin was produced by the method of Production Example 2 described below. As a result of the composition analysis performed on the polyester resin by the above-described method, the dicarboxylic acid component is CHDA, the diol component is CHDM, and PTMG is 25 weights with respect to 100 parts by weight of the polyester resin excluding the PTMG component. This was a partially copolymerized polyester resin. Moreover, it was 1.50 dl / g as a result of measuring the intrinsic viscosity of this polyester resin by the said method.
Production Example 2
Using 18.4 kg (107 mol) of CHDA having a trans isomer content of 98%, 15.6 kg (108 mol) of CHDM having a trans isomer content of 70% and 12.5 kg of PTMG having a number average molecular weight of 1,000 in the same manner as in Production Example 1, A polyester resin was obtained.

(4) Polyester resin 4 (PET4)
A polyester resin was produced by the method of Production Example 3 described below. As a result of analyzing the composition of the polyester resin by the above-described method, the dicarboxylic acid component is TPA, the diol component is EG, and PTMG is 10 weights with respect to 100 parts by weight of the polyester resin excluding the PTMG component. This was a partially copolymerized polyester resin. Moreover, it was 0.76 dl / g as a result of measuring the intrinsic viscosity of this polyester resin by the said method.
Production Example 3
Using a batch polymerization apparatus equipped with a slurry preparation tank, an esterification reaction tank, a polycondensation tank, and a pelletizing apparatus, in the esterification reaction tank containing 50 kg of the esterification reaction product of TPA and EG, Then, 43.2 kg (260 mol) of TPA and 19.4 kg (313 mol) of EG (molar ratio of dicarboxylic acid and diol was 1: 1.2) were continuously added to carry out the esterification reaction. The esterification reaction was carried out under the conditions of a reaction temperature of 250 ° C. and atmospheric pressure, without using an esterification reaction catalyst, while continuously distilling the produced water until the reaction rate reached 95%. After completion of the esterification reaction, 50 kg of the esterification reaction product was left in the esterification reaction vessel, and the esterification reaction product was transferred to the polycondensation vessel.
Subsequently, 5 kg of PTMG having a number average molecular weight of 1,000 was added to the polycondensation tank to which the esterification reaction product had been transferred, and the mixture was stirred and mixed. Next, ethyl acid phosphate was added as a stabilizer, and cobalt acetate and tetra-n-butyl titanate were added as polymerization catalysts (both were added as an EG solution). The addition amounts of ethyl acid phosphate, cobalt acetate, and tetra-n-butyl titanate were 12 ppm by weight and 24 ppm by weight, respectively, and 3 ppm by weight as Ti atoms based on the theoretical yield of the polyester resin.
Thereafter, the pressure was reduced from normal pressure to 1 mmHg, the internal temperature was raised from about 250 ° C. to about 280 ° C., and a melt polycondensation reaction was performed while distilling EG. After 4 hours from the start of decompression, the pressure was restored and the polycondensation reaction was completed. After returning the pressure in the polycondensation tank, the polyester resin was drawn out into water in the form of a strand from the bottom of the tank, and then cut into pellets.

(5) Polyester resin 5 (PET5)
A polyester resin was produced by the method of Production Example 4 described below. The polyester resin was subjected to composition analysis by the above-described method, and as a result, the dicarboxylic acid component was CHDA and the diol component was CHDM. In addition, the intrinsic viscosity of the polyester resin was measured by the above method and found to be 0.98 dl / g.
Production Example 4
In a reaction vessel equipped with a stirrer and a batch polymerization apparatus equipped with a pelletizing device, 18.4 kg (107 mol) of CHDA having a trans isomer content of 98%, 15.6 kg (108 mol) of CHDM having a trans isomer content of 70%, and 870 ml of a 6% butanol solution of tetra-n-butyl titanate was charged, heated to 150 ° C. under a nitrogen flow, and then heated to 200 ° C. Thereafter, the mixture was maintained at 200 ° C. for 1 hour to carry out an esterification reaction, and then a polycondensation reaction was carried out while gradually raising the pressure from 200 ° C. to 250 ° C. while gradually reducing the pressure in the reactor. After the polycondensation for 2.2 hours at a reactor tank pressure of 0.1 kPa and a reaction temperature of 250 ° C., the obtained polyester resin was extracted into water as a strand and then cut into a pellet.

(6) Polyester resin 6 (PET6)
“Novapex GM700Z” manufactured by Mitsubishi Chemical Corporation was used. The polyester resin was subjected to composition analysis by the above-described method, and as a result, it was a polyester resin in which the dicarboxylic acid component was TPA and the diol component was EG. Moreover, it was 0.84 dl / g as a result of measuring the intrinsic viscosity of this polyester resin by the said method.

Example 1
68 parts by weight of the raw material polyester resin PET1, 32 parts by weight of the raw material polyester resin PET2 and 15 parts by weight of aromatic polycarbonate resin ("Iupilon E-2000" manufactured by Mitsubishi Engineering Plastics) are blended, and "TEM58mm" manufactured by Toshiba Machine is extruded. Using a machine, a 200 mm wide T die die was extruded onto a cooling roll at a time discharge rate of 8 kg while pulling a vacuum vent to obtain a sheet having a width of 150 mm and a thickness of 0.20 mm. Thereafter, the above sheet was transferred to T.W. M.M. Using a “Film Stretcher” manufactured by Long, with standard specifications, stretching at a stretching temperature of 97 ° C. and a stretching speed of 3000% / min. A characteristic film was obtained. The heat shrinkable film was evaluated by the above method. The results are shown in Table 1.

Examples 2 to 4 and Comparative Examples 1 to 5
A heat-shrinkable film was obtained in the same manner as in Example 1 except that the raw material polyester resin and the aromatic polycarbonate resin were blended in the blending amounts shown in Table 1 and stretched at the stretching temperature shown in Table 1. , Evaluated in the same way. The results are shown in Table 1.

＊１ ＰＴＭＧ；ポリエステル樹脂中の含有割合（重量％）
＊２ 主収縮方向（ＭＤ）の引張弾性率を主収縮方向と直交する方向（ＴＤ）の引張弾性率で除した値

* 1 PTMG: Content in polyester resin (wt%)
* 2 Value obtained by dividing the tensile modulus in the main shrinkage direction (MD) by the tensile modulus in the direction perpendicular to the main shrinkage direction (TD).

Claims (8)

A polyester heat-shrinkable film formed by molding a resin composition comprising 100 parts by weight of a polyester resin comprising a dicarboxylic acid component, a diol component and a polyalkylene glycol component and 5 to 40 parts by weight of an aromatic polycarbonate resin, The dicarboxylic acid component constituting the polyester resin is composed of 10 to 90% by weight of aromatic dicarboxylic acid component and 90 to 10% by weight of alicyclic dicarboxylic acid component, and the content of polyalkylene glycol is based on the total amount of the polyester resin. 1 to 30% by weight, and the ratio of the tensile elastic modulus in the direction orthogonal to the main shrinkage direction of the film and the tensile elastic modulus in the main shrinkage direction is 0.30 to 0.70. Shrink film. The maximum shrinkage in the main shrinkage direction is 30% or more after being immersed in warm water at 80 ° C. for 10 seconds and then immersed in water at 23 ° C. for 30 seconds, and the maximum shrinkage in the direction perpendicular to the main shrinkage direction. The polyester heat-shrinkable film according to claim 1, wherein the rate is 5% or less. The polyester heat-shrinkable film according to claim 1 or 2, wherein the alicyclic dicarboxylic acid component constituting the polyester resin is derived from cyclohexanedicarboxylic acid. The polyester-based heat-shrinkable film according to claim 1, wherein the number average molecular weight of the polyalkylene glycol component is 500 to 6000. The polyester heat-shrinkable film according to any one of claims 1 to 4, wherein the polyalkylene glycol component is derived from polytetramethylene glycol. The polyester heat-shrinkable film according to any one of claims 1 to 5, wherein the diol component constituting the polyester resin contains an alicyclic diol component. The polyester-based heat-shrinkable film according to claim 6, wherein the content of the alicyclic diol component constituting the polyester resin is 10 to 90% by weight based on the total amount of the diol component. The polyester heat-shrinkable film according to claim 6 or 7, wherein the alicyclic diol component constituting the polyester resin is derived from cyclohexanedimethanol.