JP2005200624A - Polyester type heat-shrinkable film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester type heat-shrinkable film having good heat-shrinking properties and excellent heat resistance, giving a good shrinking finish and combining excellent breaking resistance and good flexibility. <P>SOLUTION: The film shows an elongation (A) after fracture of ≥400% for all specimens when two or more specimens are subjected to a tensile test in directions orthogonal to the principal shrinking direction of the specimens under specified conditions. When cooled after immersion in warm water, the film shows a shrinkage rate in the principal shrinking direction of 30-70%. The sum of the tensile elastic modulus in the principal shrinking direction and that in a direction orthogonal to the principal shrinking direction is 6,500 MPa or smaller. After two-week storage in an atmosphere of 35°C and a relative humidity of 50%, at least 80% of all the stored specimens show an elongation (B) after fracture of at least 90% of the average of the elongations (A) after fracture, where the elongations (B) after fracture are measured by subjecting two or more specimens to a tensile test under the same conditions. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat-shrinkable polyester film, and more specifically, because the elongation at break in the direction perpendicular to the main shrinkage direction is large, the heat-shrinkable film has a strong strength in the flow direction in the production process of the heat-shrinkable film. The edge that occurs when the film shrinks when it is used as a label for R-seal applications. In the following, the term “one”) relates to a heat-shrinkable polyester film which is not rigid and does not cause resistance even if it is touched by hand without risk of injury.

  Examples of heat-shrinkable plastic films that are widely used for shrink wrapping and shrinkage labels such as polyethylene terephthalate containers, polyethylene containers, and glass containers include stretched films such as polyvinyl chloride films, polystyrene films, and polyester films. There is. However, the polyvinyl chloride film has low heat resistance, and there is a problem that hydrogen chloride gas is generated at the time of incineration and the incinerator is easily damaged, and the polystyrene film is excellent in the finished appearance after shrinkage. There are problems such as poor solvent resistance.

On the other hand, the polyester-based heat-shrinkable film has excellent properties such as good transparency, excellent hygiene, high rigidity, and excellent heat resistance. However, there is a problem that the shrinkage start temperature is high and the shrinkage rate increases rapidly as the temperature rises. When a container with large irregularities is coated, the coating is insufficient or wrinkles occur. There was a problem that the finish was not good.
In addition, the film easily breaks in the direction perpendicular to the main shrinkage direction during film formation (the flow direction in the heat-shrinkable film manufacturing and processing process), and is coated in the printing process, tubing process, labeling process, or container There was a problem that the film was broken when it was subjected to impact after shrinking.
These phenomena tend to become prominent when the elapsed time after film production and the storage time become long even under a room temperature environment, and become more remarkable as the storage environment temperature becomes higher.
Recently, due to economic problems, there is an increasing demand for thinning and high-speed processing of heat-shrinkable films. At that time, improvement in fracture resistance (breaking resistance) is a major issue for polyester-based heat-shrinkable films. It has become.

  A heat-shrinkable polyester film excellent in rupture resistance in a direction perpendicular to the main shrinkage direction is a film having a heat shrinkage rate of 50% or more in a maximum shrinkage direction at 95 ° C. for 10 seconds, which is 30 ° C. A film is proposed in which the number of specimens with a breaking elongation of 5% or less is 10% or less of the total number of specimens when subjected to a tensile test under specific conditions for 2 weeks in an environment with a relative humidity of 85%. (See Patent Document 1). However, this film is only limited in the rate at which a test piece having a very small breaking elongation occurs after a storage test, and the magnitude of the breaking elongation of a test piece having a breaking elongation of 5% or more is It is not mentioned, and it cannot necessarily be said that the tear resistance is excellent. Therefore, this film cannot sufficiently cope with the solution of problems such as film breakage in various situations described above.

Furthermore, the high rigidity, which is also a characteristic of polyester heat-shrinkable films, may cause injury to humans due to the edges that can be formed when the film is shrunk as a label for R-seal applications. A heat shrinkable film is desired.
However, when flexibility is imparted to the film, the above-mentioned tear resistance, which is the main purpose of the present application, tends to deteriorate, and there is no polyester heat-shrinkable film that achieves both tear resistance and flexibility. It was.

JP 2003-41028 A

Since the present invention has good heat shrinkability, good shrinkage finish, excellent tear resistance, and good flexibility, when used as a label for an R-seal application, an injury caused by an edge caused by film shrinkage It is an object of the present invention to provide a polyester heat-shrinkable film capable of preventing the above-described problem, that is, a polyester heat-shrinkable film having both good tear resistance and good flexibility.
Furthermore, it aims at providing the polyester-type heat-shrinkable film which improved transparency in addition to said characteristic.

As a result of repeatedly examining the rupture resistance (breaking resistance) and flexibility of the polyester heat-shrinkable film, the inventors have a shrinkage ratio in the main shrinkage direction during heating within a specific range, and The initial value of the breaking elongation in the direction perpendicular to the main shrinkage direction is greater than or equal to a specific value, and the elongation at break after storage under specific storage conditions is above the standard in the heat shrinkable film manufacturing process. It has been found that a heat-shrinkable polyester-based film can be obtained which has few breakage troubles, can be processed at high speed, and does not have a problem of tearing even after production. It has been found that in order for the edge generated by shrinkage to have such a degree of flexibility that there is no danger, the sum of the tensile elastic modulus in the main shrinkage direction and the direction perpendicular thereto should be a certain value or less. .
In the polyester heat-shrinkable film, a polyester resin containing an alicyclic dicarboxylic acid component as the polyvalent carboxylic acid component and an alicyclic diol component and a polyalkylene glycol component as the polyhydric alcohol component is used. By doing so, it was found that it is advantageous in having both tear resistance and flexibility.
Furthermore, by adding an aromatic polycarbonate resin to such a polyester resin, the compatibility between the polyester constituents is increased. As a result, transparency is improved and a preferable heat-shrinkable polyester film having a better shrink finish is obtained. It was also found that it can be obtained.

That is, the present invention
(1) A plurality of test pieces cut into a strip shape having a length of 15 mm in the main contraction direction and a length of 100 mm in a direction orthogonal to the main contraction direction, a distance between chucks of 20 mm and a temperature of 23 in the direction orthogonal to the main contraction direction. The breaking elongation (A) when tensile tested at 200 ° C. and a tensile rate of 200 mm / min is 400% or more in all test pieces, and after being immersed in warm water at 80 ° C. for 10 seconds, then at 23 ° C. for 30 seconds. A polyester-based heat-shrinkable film having a shrinkage ratio in the main shrinkage direction of 30 to 70% when immersed and cooled,
The sum of the tensile elastic modulus in the main shrinkage direction and the tensile elastic modulus in the direction perpendicular to the main shrinkage direction is 6,500 MPa or less, and after storing in an atmosphere at a temperature of 35 ° C. and a relative humidity of 50% for 2 weeks, The number of test pieces having a breaking elongation (B) of 90% or more of the average value of the breaking elongation (A) when a plurality of test pieces cut into the same shape are subjected to a tensile test under the same conditions as described above. Is a polyester-based heat-shrinkable film characterized by being 80% or more of the total number of test pieces,
(2) In the polyester heat-shrinkable film, the alicyclic dicarboxylic acid component in the polyvalent carboxylic acid component is 5 mol% or more, and the alicyclic diol component in the polyhydric alcohol component is 10 mol% or more. And a polyester-based heat-shrinkable film according to the above (1), which contains 2 to 15% by weight (in a polyester resin) of a polyalkylene glycol having a number average molecular weight of 500 to 6,000,
(3) The alicyclic dicarboxylic acid component in the polyvalent carboxylic acid component is 10 to 60 mol%, and the alicyclic diol component in the polyhydric alcohol component is 20 to 60 mol%. Polyester heat shrinkable film.
(4) The alicyclic dicarboxylic acid component in the polyvalent carboxylic acid component is 5 mol% or more, the alicyclic diol component in the polyhydric alcohol component is 10 mol% or more, and the number average molecular weight is 500. The polyester according to (1) above, comprising a resin composition obtained by mixing 1 to 100 parts by weight of an aromatic polycarbonate resin with 100 parts by weight of a polyester resin containing 2 to 15% by weight of a polyalkylene glycol of ˜6,000. Heat shrinkable film,
(5) The above (2) in which the alicyclic dicarboxylic acid component is 1,4-cyclohexanedicarboxylic acid, the alicyclic diol component is 1,4-cyclohexanedimethanol, and the polyalkylene glycol is polytetramethylene ether glycol. ) To (4) polyester heat shrinkable film according to any one of
Is to provide.

The present invention has good heat shrinkability, good shrink finish, and excellent resistance to tearing even after long-term storage.Therefore, there are few breakage troubles in the production process of heat shrinkable films, and high speed processing is possible. Polyester-based heat-shrinkable film that does not break even after production, and has good flexibility, so when used as a label for R-seal applications, polyester-based heat that can prevent injuries due to edges generated during film shrinkage A shrinkable film, that is, a polyester heat-shrinkable film having both good tear resistance and good flexibility is provided.
The polyester heat-shrinkable film of the present invention includes a polyester resin containing an alicyclic dicarboxylic acid component in a polyvalent carboxylic acid component and an alicyclic diol component and a polyalkylene glycol component in a polyhydric alcohol component. It is advantageous to use both in order to have both tear resistance and flexibility. Further, by adding an aromatic polycarbonate resin, the compatibility between the polyester constituents is increased, the transparency is improved, and a heat-shrinkable polyester film having a better shrink finish can be obtained.

  The polyester-based heat-shrinkable film of the present invention has a plurality of test pieces cut into a strip shape having a length of 15 mm in the main shrinkage direction and a length of 100 mm in the direction perpendicular to the main shrinkage direction, in the direction perpendicular to the main shrinkage direction. After immersing in hot water of 80 ° C. for 10 seconds, the elongation at break (A) is 400% or more in all the test pieces when the 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. It is necessary to be a polyester heat-shrinkable film having a shrinkage rate in the main shrinkage direction of 30 to 70% when immersed and cooled in water at 23 ° C. for 30 seconds.

About the direction perpendicular to the main shrinkage direction, the elongation at break (A) is 400% or more, and in the heat shrinkable film manufacturing process, the strength in the flow direction is strong and there are few troubles of breakage of the heat shrinkable film band. It is necessary for high-speed processing, and the elongation at break (A) is preferably 500% or more.
In addition, the fact that the shrinkage rate in the main shrinkage direction after cooling at 80 ° C. in hot water is 30 to 70% is good in heat shrinkability, and the shrink finish after packaging into containers such as PET bottles and glass bottles. It is a necessary condition for being good, and is more preferably 40% to 70%. When the shrinkage rate is 70% or more, wrinkles or distortions occur in the film, resulting in poor shrinkage finish.

  The polyester-based heat-shrinkable film of the present invention is stored for 2 weeks in an atmosphere at a temperature of 35 ° C. and a relative humidity of 50%, and then a plurality of test pieces cut into the same shape as described above are pulled under the same conditions as described above. The number of test pieces whose breaking elongation (B) when tested is 90% or more of the average value of the breaking elongation (A) is required to be 80% or more of the total number of test pieces.

The storage condition of 2 weeks in an atmosphere at a temperature of 35 ° C. and a relative humidity of 50% is an accelerated test for evaluation of breaking elongation (breaking resistance) over time. In particular, the storage temperature of 35 ° C. is a temperature of the polyester heat-shrinkable film. This is a severe condition as compared with the normal upper limit of storage temperature of 25 ° C.
If the number of test pieces whose breaking elongation (B) in the tensile test after storage under such conditions is 90% or more of the average value of breaking elongation (A) is 80% or more of the total number of test pieces, In the manufacturing process of heat-shrinkable film, the strength in the longitudinal direction> flow direction is strong, and there are almost no troubles of breaking the heat-shrinkable film band, and thinning and high-speed processing are possible, and there is no problem of tearing after manufacturing. It can be a heat-shrinkable polyester film. Even if time elapses at each stage from the production of the polyester-based heat-shrinkable film to the production / processing of the heat-shrinkable film and the packaging in the container, the trouble of breakage is reduced. Of course, it is preferable that the specimen having a breaking elongation (B) of 90% or more of the average breaking elongation (A) is closer to 100%.

  Furthermore, the polyester heat-shrinkable film of the present invention requires that the sum of the tensile elastic modulus in the main shrinking direction and the tensile elastic modulus in the direction orthogonal to the main shrinking direction is 6,500 MPa or less.

Here, for each tensile modulus, a test piece having a length of 70 mm and a width of 5 mm was taken in the main shrinkage direction of the film, and a test piece having a length of 70 mm and a width of 5 mm was taken in a direction perpendicular to the main shrinkage direction. These are subjected to a tensile test at a chuck interval of 50 mm, a temperature of 23 ° C., and a tensile speed of 5 mm / min, and are obtained by the following formula in the straight line portion immediately after the start of the test of the stress-strain curve in the length direction.
"Tensile modulus" (MPa) = Stress difference between two points on a straight line divided by the initial cross-sectional area / Strain difference between the same two points

  The sum of the tensile elastic modulus in the main shrinkage direction and the tensile elastic modulus in the direction perpendicular to the main shrinkage direction is an index of the flexibility of the film, meaning that the smaller it is, the softer it is. The edge produced by film shrinkage during container packaging is so flexible that there is no danger. If the sum of the tensile elastic moduli is in the range of 1500 to 6500 MPa, the required strength is maintained and the edge has no risk of flexibility. A range of 2000 to 6000 MPa is more preferable.

  The polyester-based heat-shrinkable film of the present invention has an alicyclic dicarboxylic acid component in the polyvalent carboxylic acid component of 5 mol% or more, an alicyclic diol component in the polyhydric alcohol component of 10 mol% or more, and To use a polyester resin containing 0.5 to 15% by weight (in the polyester resin) of a polyalkylene glycol having a number average molecular weight of 500 to 6,000 in order to have both tear resistance and flexibility It is advantageous.

It does not specifically limit as an alicyclic dicarboxylic acid compound used for the said alicyclic dicarboxylic acid component, For example, 1, 3- cyclohexane dicarboxylic acid, 1, 4- cyclohexane dicarboxylic acid or its ester-forming derivative etc. are mentioned suitably. It is done. Among these, 1,4-cyclohexanedicarboxylic acid or an ester-forming derivative thereof is particularly preferable from the viewpoints of shrinkability and heat resistance. Further, the trans / cis isomer ratio of 1,4-cyclohexanedicarboxylic acid or an ester-forming derivative thereof is preferably 80 mol% or more from the viewpoint of heat resistance.
The alicyclic diol compound used for the alicyclic diol component is not particularly limited, but 1,1-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4 -Cyclohexanedimethanol, 1,2-cyclohexanediol, 1,4-cyclohexanediol and the like are exemplified, among which 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.
These alicyclic dicarboxylic acid component and alicyclic diol component disturb the crystallinity of polyester made of crystalline ethylene terephthalate and the like to increase the degree of non-crystallization, thereby providing elasticity and flexibility. By exhibiting a high heat shrinkage ratio in the film, improving the shrink finish, and containing each of the above-mentioned predetermined mol% or more, the fracture resistance (breaking resistance) required for the polyester heat shrinkable film of the present invention ) Can be improved.

In the polyester heat-shrinkable film of the present invention, it is preferable that a polyalkylene glycol component is further included as a polyhydric alcohol component 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, ethylene oxide and propylene oxide block or random copolymer Examples include coalescence. Two or more of these can be used in combination. Among these, polyethylene glycol and polytetramethylene glycol are preferable, and polytetramethylene glycol is particularly preferable.

The number average molecular weight of the polyalkylene glycol is preferably in the range of 500 to 6,000, more preferably 500 to 2,500, and particularly preferably 600 to 2,000. When the number average molecular weight is 500 or more, the tensile elasticity modulus of the resulting polyester heat-shrinkable film does not become too high, whereas when it is 2,500 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.

The polyester heat-shrinkable film of the present invention preferably contains an alicyclic dicarboxylic acid component as the polyvalent carboxylic acid component of the polyester as described above, but can contain other polyvalent carboxylic acid components.
As another polyvalent carboxylic acid component, it is preferable that it contains many aromatic dicarboxylic acid components. 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-forming derivatives thereof. An acid or an ester-forming derivative thereof is particularly preferable since it has high crystallinity particularly when ethylene glycol or the like is used as a diol component, so that sufficient strength can be ensured in the polyester heat-shrinkable film.

In the polyester heat-shrinkable film of the present invention, in order for the alicyclic dicarboxylic acid component to increase the degree of amorphization and exhibit desired effects such as shrinkage properties, shrinkage finish properties, and tear resistance, Although it is necessary to contain 5 mol% or more in the acid component, it is preferably 10 mol% or more in order to express these effects better. However, if the amount of the alicyclic dicarboxylic acid component is excessive, problems such as a decrease in transparency and a decrease in sealing properties may occur.
Furthermore, when the aromatic dicarboxylic acid component is contained, the total amount of the alicyclic dicarboxylic acid component and the aromatic dicarboxylic acid component is 80 mol% or more with respect to the total amount of the polyvalent carboxylic acid component. To preferred.

  Furthermore, in the polyester resin that can be used in the polyester-based heat-shrinkable film of the present invention, polyvalent carboxylic acid compounds other than the above-described dicarboxylic acid compounds may be copolymerized within a range that does not impair the effects of the present invention. . Examples of such polyvalent carboxylic acid compounds include aliphatic dicarboxylic acids such as malonic acid, succinic acid, adipic acid, azelaic acid, and sebacic acid.

In the polyester heat-shrinkable film of the present invention, it is preferable to contain an alicyclic diol component and a polyalkylene glycol component as the polyhydric alcohol component of the polyester as described above, but other polyhydric alcohol components are included. be able to.
As another polyhydric alcohol component, it is preferable to use an aliphatic diol compound as a main component. Specifically, 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.

  In the polyester-based heat-shrinkable film of the present invention, the alicyclic diol component increases the degree of amorphization and exhibits desired effects such as shrinkage properties, shrinkage finish properties, and breakage resistance (breaking resistance). The polyhydric alcohol component needs to be contained in an amount of 10 mol% or more, but is preferably 20 mol% or more in order to better exhibit these effects. However, if the amount of the alicyclic diol component increases too much, the shrinkage ratio of the film becomes unnecessarily high, the solvent resistance of the film decreases, or the film becomes too flexible and the resistance to tearing decreases. Since it may occur, it is preferably suppressed to 60 mol% or less.

The content of the polyalkylene glycol component is preferably in the range of 0.5 to 15% by weight in the polyester resin.
More preferably, it is preferably copolymerized in the range of 1 to 5% by weight.

  Moreover, in the polyester resin which can be used for the polyester-type heat-shrinkable film of the present invention, for example, 4,4′-dihydroxybiphenyl, 2,2-bis (4 ′), as long as the effects of the present invention are not impaired. Aromatic diols such as -hydroxyphenyl) propane, 2,2-bis (4'-β-hydroxyethoxyphenyl) propane, bis (4-hydroxyphenyl) sulfone, bis (4-β-hydroxyethoxyphenyl) sulfone; glycol Hydroxycarboxylic acids and alkoxycarboxylic acids such as acid, p-hydroxybenzoic acid and p-β-hydroxyethoxybenzoic acid; simple substances such as stearic acid, stearyl alcohol, benzyl alcohol, benzoic acid, t-butylbenzoic acid and benzoylbenzoic acid Functional component: Tricarballylic acid, hexanetri Rubonic acid, trimellitic acid, trimesic acid, pyromellitic acid, benzophenonetetracarboxylic acid, naphthalenetetracarboxylic acid, 1,2,6-hexanetriol, gallic acid, trimethylolethane, trimethylolpropane, glycerol, pentaerythritol, sorbitol, di A trifunctional or higher polyfunctional component such as pentaerythritol and polyglycerol may be copolymerized.

The above-mentioned polyester resin that can be suitably used for the polyester-based heat-shrinkable film of the present invention can be produced batchwise or continuously by a conventional production method of a polyester resin such as a direct polymerization method or a transesterification 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 solid phase polycondensation by heat treatment, the degree of polymerization can be further increased, and acetaldehyde, low-molecular oligomers, and the like as reaction by-products can be reduced.

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.
In addition, an antifoaming agent such as silicone oil can be added to promote defoaming in the polymerization process.

  The polyester resin suitably used in the present invention has an intrinsic viscosity of usually 0.4 to 4 measured at 30 ° C. in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane (weight ratio of 1: 1). The range is preferably 1.5 dl / g. When it is 0.4 dl / g or more, sufficient mechanical properties are obtained, and when it is less than 1.5 dl / g, molding is easy. 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 can be obtained by a known method as will be described later, but a method for incorporating the polyvalent carboxylic acid component and the polyhydric alcohol component as a polyester resin component in the film. As the target composition, each of these components is blended and copolymerized to obtain a single polyester resin, and a plurality of raw polyester resins that are homopolyesters or copolyesters of different compositions. Any method of the blend method which prepares and mixes these by the ratio used as a target composition and obtains a polyester resin may be sufficient. 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 polyester-based heat-shrinkable film of the present invention is obtained by forming a resin composition containing 1 to 100 parts by weight of an aromatic polycarbonate resin with respect to 100 parts by weight of the polyester resin described above. In addition to the properties, a polyester heat-shrinkable film having further improved shrinkage finish and transparency can be obtained.
The aromatic polycarbonate resin is preferably contained in an amount of 5 parts by weight or more, and the upper limit is preferably 60 parts by weight, and more preferably 50 parts by weight.
In addition, when using the copolymer which consists of alicyclic dicarboxylic acid, alicyclic diol, and polyalkylene glycol as a polyester resin, aromatic polycarbonate resin 20 ~ with respect to 100 weight part of the said copolymers. It is preferable to form a resin composition containing 100 parts by weight, preferably 25 parts by weight or more, preferably 60 parts by weight or less, more preferably 50 parts by weight or less.
Here, the aromatic polycarbonate resin is not particularly limited, but is preferably a bisphenol-type polycarbonate resin from the viewpoint of availability.
In addition, the resin composition containing the polyester resin and the aromatic polycarbonate resin is prepared by mixing the polyester resin and the aromatic polycarbonate resin. It can also be obtained as a combined resin.

In the present invention, the resin composition of the polyester resin or polyester resin / aromatic polycarbonate resin is inorganic and / or organic because it can provide blocking resistance and slipperiness when formed into a heat-shrinkable film. It is preferable that fine particles are contained. 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, especially 0.02 to the total amount of the heat-shrinkable film. The range is preferably 0.5% 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 0.001 to 6 μm, more preferably in the range of 0.005 to 4 μm, particularly in the range of 0.01 to 3 μm, from the viewpoint of the above-described effects. is there. The average particle diameter means 50% volume average particle diameter (d50) measured by a laser diffraction method.
Further, the mixing method of the fine particles is not particularly limited, and can be added during the polymerization process of the polyester resin. When a resin composition is used, the process of producing the composition, and further the heat shrinkable film forming process Can also be mixed.

The resin used for the polyester heat-shrinkable film of the present invention may further be mixed with other resins within a range not impairing the effects of the present invention. For example, polyethylene, polypropylene, these modified maleic anhydrides, polyolefin resins such as ionomers, thermoplastic resins such as polyamide resins and polystyrene resins, thermoplastic elastomers, and the like.
Furthermore, light stabilizers such as hindered phenols, phosphites, thioethers, benzotriazoles, benzophenones, benzoates, hindered amines, cyanoacrylates, inorganic or organic crystal nuclei Contains additives such as additives, molecular weight modifiers, hydrolysis resistance, antistatic agents, lubricants, mold release agents, plasticizers, flame retardants, flame retardant aids, foaming agents, colorants, and dispersion aids. May be.

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 polyester resin or resin composition is melt-extruded and cut at a temperature of 200 to 300 ° C. in advance. It is also possible to produce a heat-shrinkable film by forming into a pellet and then melt-extruding the pellet at a temperature of 200 to 300 ° C. Moreover, the said polyester resin or the said resin composition can be melt-extruded at the temperature of 200-300 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 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, about said extending | stretching temperature, after being immersed in 80 degreeC warm water for 10 second and then being immersed and cooled for 30 seconds in 23 degreeC water, the shrinkage | contraction rate of the main contraction direction is 30% or more, Preferably it is 40%-70. What is necessary is just to determine 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, mill ends generated when a sheet, film, fiber, molded container, bottle or the like is molded from a polyester resin or resin composition that can be suitably used for the polyester heat-shrinkable film of the present invention, Or what melt | dissolved the resin composition which concerns on this invention once, and was made into the pellet form 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.

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) Shrinkage at 80 ° C. The film in each Example or Comparative Example was cut to a size of 70 mm in the stretching direction (main shrinkage direction) and 10 mm in the direction perpendicular to this to prepare a sample. A marked line with a 50 mm interval is attached to the extending direction of the sample, dipped in a warm water bath at 80 ° C. for 10 seconds, and then immersed and cooled in cold water at 23 ° C. for 30 seconds to measure the marked line interval (D). The 80 ° C. shrinkage was calculated from (1).
“80 ° C. Shrinkage” (%) = 100 × (50−D) / 50 (1)
(2) Sum of tensile elastic modulus A plurality of test pieces having a length of 70 mm and a width of 5 mm are taken in the main shrinkage direction of the film, and a plurality of test pieces having a length of 70 mm and a width of 5 mm are taken in a direction perpendicular to the main shrinkage direction. A sheet was collected. Each test piece was set in a tensile tester installed in a thermostatic chamber at 50 ° C. with a chuck distance of 50 ° C., and a stress-strain curve in the length direction was obtained at a tensile test speed of 5 mm / min. The tensile modulus was obtained from the formula. The average value of the measured values of the tensile modulus in the main shrinkage direction and the average value of the measured values of the tensile modulus in the direction orthogonal to the main shrinkage direction were obtained, and the sum was calculated.
“Tensile modulus” (MPa) = Stress difference between two points on a straight line divided by the initial cross-sectional area / Strain difference between the same two points (3) Tightness From the film in each example or comparative example to FIG. The overlapped bag-making product was produced, and the tactile sensation was evaluated with respect to the hardness of “one end” (1) formed at the shoulder of the mouth when heat shrinking. The heat shrinking process was performed by passing through the tunnel at a tunnel temperature of 85 ° C. for 10 seconds using a SK system 3000 “SKT-3000 type” steam shrinking tunnel. After that, tactile sensation evaluation was performed for “end of the two”. The evaluation criteria are as follows.
○: Resistance is small, Δ: Slight resistance is felt, X: Strong resistance is felt (4) Shrinkage finish The film in each Example or Comparative Example is formed into a cylindrical shape so that the stretching direction is the transverse direction, and filled with water The film was put on a 350 mL plastic bottle, and the shrinkage state after passing through a steam shrink tunnel adjusted to 80 to 90 ° C. for 5 seconds was observed and judged according to the following criteria.
○: Clean appearance without shrinkage unevenness and wrinkles Δ: Appearance with slight shrinkage unevenness and wrinkles ×: Appearance with significant shrinkage unevenness and wrinkles (5) Elongation at break 10 or more test pieces cut into a strip shape with a length of 15 mm and a direction perpendicular to the main shrinkage direction of 100 mm in length, a distance between chucks of 20 mm, a temperature of 23 ° C., and a pulling speed of 200 mm in the direction perpendicular to the main shrinkage direction. Tensile tests were performed at 1 min.

(Polyester resin)
The raw material polyester resin used in each example and comparative example will be described below.
(1) Polyester resin 1 (PET1)
“EMBRACE Copolyester” 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”). 72 mol% with respect to the total diol, 1,4-cyclohexanedimethanol (hereinafter abbreviated as “CHDM”) is 20 mol% with respect to the total diol, and diethylene glycol (hereinafter abbreviated as “DEG”). Was a polyester resin having 8 mol% based on the total diol. Moreover, it was 0.83 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 above-described method, the dicarboxylic acid component is 1,4-cyclohexanedicarboxylic acid (hereinafter abbreviated as “CHDA”), the diol component is CHDM, Tetramethylene glycol (hereinafter abbreviated as “PTMG”) was a polyester resin copolymerized by 10 parts by weight with respect to 100 parts by weight of the polyester resin. 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)
“EASTAR PETG Copolyester 6763” manufactured by Eastman Chemical Co. was used. As a result of performing composition analysis on the polyester resin by the above-described method, the dicarboxylic acid component was TPA, and the diol component was EG at 68 mol% with respect to the total diol, and CHDM at 32 mol% with respect to the total diol. It was a certain polyester resin. Moreover, it was 0.78 dl / g as a result of measuring the intrinsic viscosity of this polyester resin by the said method.

(4) Polyester resin 4 (PET4)
“Novaduran 5008” manufactured by Mitsubishi Engineering Plastics was used. The polyester resin was subjected to composition analysis by the above-described method. As a result, it was a polyester resin in which the dicarboxylic acid component was TPA and the diol component was 1,4-butanediol (hereinafter abbreviated as “BD”). It was. Moreover, it was 0.85 dl / g as a result of measuring the intrinsic viscosity of this polyester resin by the said method.

(5) Polyester resin 5 (PET5)
A polyester resin was produced by the method of Production Example 2 described below. As a result of the composition analysis of the polyester resin by the above-described method, the dicarboxylic acid component was such that TPA was 70 mol% with respect to the total dicarboxylic acid, and isophthalic acid (hereinafter abbreviated as “IPA”) was the total dicarboxylic acid. It was 30 mol% with respect to the polyester resin whose diol component was EG. Moreover, it was 0.81 dl / g as a result of measuring the intrinsic viscosity of this polyester resin by the said method.
Production Example 2
Polyester resin in which the dicarboxylic acid component is 70 mol% of TPA with respect to all dicarboxylic acids, isophthalic acid (hereinafter abbreviated as “IPA”) is 30 mol% with respect to all dicarboxylic acids, and the diol component is EG. (Hereinafter abbreviated as “PET5”);
Using a batch polymerization apparatus equipped with a slurry preparation tank, an esterification reaction tank, a polycondensation tank, and a pelletizing apparatus, a mixture of TPA and IPA (4: 1 molar ratio) and 50 kg of EG esterification reaction product were added. In an esterification reaction tank, TPA 30.2 kg (182 mol), IPA 13.0 kg (78 mol) and EG 19.4 kg (313 mol) prepared in advance in a slurry preparation tank (molar ratio of dicarboxylic acid and diol was 1: 1. The slurry of 2) was continuously added to carry out the esterification reaction. In the esterification reaction, 200 ppm by weight of antimony trioxide is added as the esterification reaction catalyst to the theoretical yield of the polyester resin under the conditions of a reaction temperature of 250 ° C. and atmospheric pressure, and the resulting water is continuously distilled off. However, the esterification reaction was carried out 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, orthophosphoric acid was added as a stabilizer to the polycondensation tank to which the esterification reaction product was transferred, and cobalt acetate and diantimony trioxide were added as polymerization catalysts (both were added as an EG solution). The addition amounts of orthophosphoric acid, cobalt acetate, and antimony trioxide were 60 ppm by weight, 150 ppm by weight, and 200 ppm by weight, respectively, with respect to 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.

(6) Polyester resin 6 (PET6)
A polyester resin was produced by the method of Production Example 3 described below. As a result of performing composition analysis on the polyester resin by the above-described method, the dicarboxylic acid component is CHDA, the diol component is CHDM, and PTMG is copolymerized by 25 parts by weight with respect to 100 parts by weight of the polyester resin. 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 3
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 as raw materials, the same method as for polyester resin 2 was used. A polyester resin was obtained.

Example 1
90 parts by weight of polyester resin PET1 and 10 parts by weight of polyester resin PET2 are blended. Using a TEM 58mm extruder manufactured by Toshiba Machine, a vacuum vent is pulled from a 200mm wide T die die on a cooling roll at a time discharge rate of 8kg. And a sheet having a width of 150 mm and a thickness of 0.20 mm was obtained. Thereafter, the above sheet was transferred to T.W. M.M. Using a “Film Stretcher” manufactured by Long as standard specifications, the film was stretched 4 times in the direction perpendicular to the casting extrusion direction at a stretching temperature of 77 ° 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, Comparative Examples 1 to 4
A polyester resin and an aromatic polycarbonate resin were blended in the blending amounts shown in Table 1, and a heat-shrinkable film was obtained in the same manner as in Example 1 and evaluated in the same manner. The results are shown in Table 1.

It is a conceptual diagram which shows the aspect of R seal use of a heat shrink film.

Explanation of symbols

A: Bag-making product made of heat-shrinkable film B: Container 1:

Claims (5)

A plurality of test pieces cut into a strip shape having a length of 15 mm in the main shrinkage direction and a length of 100 mm in a direction perpendicular to the main shrinkage direction are 20 mm between chucks, a temperature of 23 ° C., a tensile force in the direction perpendicular to the main shrinkage direction. The breaking elongation (A) when a tensile test was performed at a speed of 200 mm / min was 400% or more in all test pieces, and after immersion in warm water at 80 ° C. for 10 seconds, immersion cooling was performed for 30 seconds in 23 ° C. water. A polyester-based heat-shrinkable film having a shrinkage ratio in the main shrinkage direction of 30 to 70%,
The sum of the tensile elastic modulus in the main shrinkage direction and the tensile elastic modulus in the direction perpendicular to the main shrinkage direction is 6,500 MPa or less, and after storing in an atmosphere at a temperature of 35 ° C. and a relative humidity of 50% for 2 weeks, The number of test pieces having a breaking elongation (B) of 90% or more of the average value of the breaking elongation (A) when a plurality of test pieces cut into the same shape are subjected to a tensile test under the same conditions as described above. Is a polyester heat-shrinkable film, characterized in that it is 80% or more of the total number of test pieces. In the polyester heat-shrinkable film, the alicyclic dicarboxylic acid component in the polyvalent carboxylic acid component is 5 mol% or more, the alicyclic diol component in the polyhydric alcohol component is 10 mol% or more, and The polyester heat-shrinkable film according to claim 1, comprising 0.5 to 15% by weight (in a polyester resin) of a polyalkylene glycol having a number average molecular weight of 500 to 6,000. The polyester-based heat shrinkage according to claim 2, wherein the alicyclic dicarboxylic acid component in the polyvalent carboxylic acid component is 10 to 60 mol%, and the alicyclic diol component in the polyhydric alcohol component is 20 to 60 mol%. Sex film. At least the alicyclic dicarboxylic acid component in the polyvalent carboxylic acid component is 5 mol% or more, the alicyclic diol component in the polyhydric alcohol component is 10 mol% or more, and the number average molecular weight is 500 to The polyester according to claim 1, comprising a resin composition containing 1 to 100 parts by weight of an aromatic polycarbonate resin with respect to 100 parts by weight of a polyester resin containing 0.5 to 15% by weight of a polyalkylene glycol of 6,000. Heat shrinkable film. The alicyclic dicarboxylic acid component is 1,4-cyclohexanedicarboxylic acid, the alicyclic diol component is 1,4-cyclohexanedimethanol, and the polyalkylene glycol is polytetramethylene ether glycol. The polyester heat-shrinkable film according to any one of the above.

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