JP2007145956A - Polyester resin and polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat-shrinkable polyester film which reduces occurrence of whitening, shrinkage spots, creases, and strain on mounting on an adherend, excels in solvent adhesion, and has good ink releasability with an alkali aqueous solution, and a polyester resin suitable therefor. <P>SOLUTION: The heat-shrinkable polyester film is obtained by stretching a polyester film containing a polyester resin comprising an acid component containing 3-9 mol% adipic acid unit and an alcohol component containing 10-15 mol% 1,4-cyclohexanedimethanol unit in at least one direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polyester resin, and more particularly to a polyester resin suitable for a heat-shrinkable polyester film and a heat-shrinkable polyester film.

  Conventionally, heat-shrinkable films have been used for labels and cap seals of various containers such as PET bottles, glass containers, and polyethylene containers, coating of electronic parts, and integrated packaging, etc., by utilizing the property of shrinking by heating. The heat-shrinkable film made of polyester resin is widely used because it is excellent in environmental aspect, heat resistance and chemical resistance.

However, polyester resin is excellent in chemical resistance, so when sealing the left and right edges of the film by solvent bonding to form a tube-like body, use a highly harmful solvent containing chlorine such as methylene chloride as the solvent. Otherwise, there was a drawback that it was difficult to obtain a sealing strength by solvent adhesion. Therefore, in recent years, tetrahydrofuran (hereinafter abbreviated as THF) and 1,3-dioxolane have been used as a solvent to replace methylene chloride. However, when THF or 1,3-dioxolane is used, the solvent adhesiveness is low, so studies have been made to improve the solvent adhesiveness of the film (for example, see Patent Documents 1 to 3).
However, in the polyester films described in Patent Documents 1 to 3, since the shrinkage rate in the direction orthogonal to the main shrinkage direction is large and the shrinkage stress is small, the finish when used as a label is poor, and the adhesiveness to the bottle There was a problem in shrinkage characteristics, such as not being excellent.

Further, in recent years, for PET bottle labels and the like, inks that are desorbed in an alkaline aqueous solution for the purpose of recycling and inks that reduce or do not use organic solvents that adversely affect the environment or human body have been developed. In order for these inks to achieve a predetermined purpose, the ink adhesion to the film may be lower than that of the conventional type. For this reason, a film with low solvent adhesion with THF or 1,3-dioxolane cannot be coated with an alkali release layer of the ink, and there is a problem in alkali release in the recycling process.
JP 2001-151908 A JP 2002-46175 A JP 2002-212405 A

  Therefore, the object of the present invention is excellent in shrinkage properties when it is made into a heat-shrinkable polyester film, specifically, when it is attached to a body to be worn, there is little occurrence of whitening, shrinkage spots, wrinkles, distortion, Another object of the present invention is to provide a heat-shrinkable polyester film that is excellent in solvent adhesion such as a center seal and has good ink releasability with an alkaline aqueous solution, and a polyester resin suitable for obtaining the heat-shrinkable polyester film. It is to provide.

  The present invention relates to a polyester resin comprising an acid component containing 3 to 9 mol% adipic acid units and an alcohol component containing 10 to 15 mol% 1,4-cyclohexanedimethanol units, and the polyester resin The present invention relates to a polyester film containing

  By stretching the polyester film of the present invention in at least one direction, a polyester film having excellent shrinkage characteristics, good solvent adhesion, and good ink detachment with an aqueous alkali solution can be obtained. Therefore, the polyester resin of the present invention and the polyester film containing the polyester resin are usefully used for, for example, labels and cap seals of various containers such as PET bottles, glass containers, and polyethylene containers, coating of electronic components, and integrated packaging. be able to.

Hereinafter, the present invention will be described in detail.
The polyester resin of the present invention comprises an acid component and an alcohol component.
An acid component contains 3-9 mol% of adipic acid units with respect to 100 mol% of all the acid components in a polyester resin, More preferably, 4-8 mol% is contained. When the content of the adipic acid unit is within this range, the shrink film is excellent in heat shrinkability from a low temperature, and there is a tendency that appearance defects such as wrinkles and unevenness after labeling do not occur. In addition, there is no problem such as white turbidity, wrinkles or unevenness when the solvent penetrates, and sufficient solvent adhesiveness tends to be obtained.
The acid component other than the adipic acid unit is not particularly limited, but it is preferable that the terephthalic acid unit is a main component (50 mol% or more in the acid component).

In the present invention, divalent acid component units other than terephthalic acid units and adipic acid units can also be used. For example, isophthalic acid unit, 1,4-naphthalenedicarboxylic acid unit, 2,6-naphthalenedicarboxylic acid unit, anthracene dicarboxylic acid unit, 4,4′-diphenyldicarboxylic acid unit, 4,4′-diphenyl ether dicarboxylic acid unit, 5 -Sulfoisophthalic acid unit, 3-sulfoisophthalic acid sodium unit, oxalic acid unit, succinic acid unit, glutaric acid unit, pimelic acid unit, sebacic acid unit, azelaic acid unit, dodecanedicarboxylic acid unit, dimer acid unit, 1,3 -A cyclohexane dicarboxylic acid unit, a 1, 4- cyclohexane dicarboxylic acid unit, a 1, 3- cyclopentane dicarboxylic acid unit, a 4,4'- dicyclohexyl dicarboxylic acid unit, etc. are mentioned.
The content of these divalent acid component units is not particularly limited, but is preferably 5 mol% or less for the purpose of adjusting shrinkage behavior, shrinkage start temperature, and solvent adhesiveness.

  Moreover, you may contain a polyvalent carboxylic acid unit more than trivalence as an acid component. The content of the trivalent or higher polyvalent carboxylic acid unit is not particularly limited, but is preferably 2 mol% or less, more preferably 1.5 mol% or less, and more preferably 1 mol% or less with respect to 100 mol% of all acid components. Particularly preferred. When the content of the trivalent or higher polyvalent carboxylic acid unit is within this range, it tends to be able to improve shrinkage behavior, improve fluidity, impart drawdown resistance, shorten the polymerization time, and the like. Although it does not restrict | limit especially as a polyvalent carboxylic acid unit more than trivalence, For example, a trimellitic acid unit, a pyromellitic acid unit, etc. are mentioned.

An alcohol component contains 10-15 mol% of 1, 4- cyclohexane dimethanol units with respect to 100 mol% of all the alcohol components in polyester, More preferably, it contains 11-14 mol%. When the content of 1,4-cyclohexanedimethanol unit is within this range, the film becomes flexible and the blocking property is not deteriorated, and sufficient heat shrinkability is obtained as a shrink film. There is a tendency that appearance defects such as unevenness do not occur. In addition, there is no problem such as white turbidity, wrinkles or unevenness when the solvent penetrates, and sufficient solvent adhesiveness tends to be obtained.
Moreover, although alcohol components other than a 1, 4- cyclohexane dimethanol unit are not restrict | limited in particular, it is preferable to make an ethylene glycol unit into a main component (50 mol% or more in an alcohol component).

  In the present invention, alcohol component units other than 1,4-cyclohexanedimethanol and ethylene glycol can be used. For example, diethylene glycol unit, triethylene glycol unit, propylene glycol unit, 1,4-butanediol unit, 1,6-hexanediol unit, neopentyl glycol unit, dimer diol unit, 1,4-cyclohexanediol unit, 1,4 -Bis (2-hydroxyethoxy) benzene unit, polyethylene glycol unit, polypropylene glycol, polyethylene glycol-polypropylene glycol block copolymer unit, polyethylene glycol-polypropylene glycol random copolymer unit, polytetramethylene glycol unit, polyhexamethylene glycol Examples include units and glycol units represented by the following general formulas (1), (2) and (3). These alcohol components can be used in a proportion of 5 mol% or less for the purpose of adjusting the shrinkage behavior, shrinkage start temperature, and solvent adhesion.

（式中、ＸはＣＨ₂、Ｃ(ＣＨ₃)₂、Ｃ(ＣＦ₃)₂、Ｏ、Ｓ、及びＳＯ₂を示し、ｍ及びｎは、１≦ｍ＋ｎ≦４を満足する。）

（式中、ＸはＣＨ₂、Ｃ(ＣＨ₃)₂、Ｃ(ＣＦ₃)₂、Ｏ、Ｓ、及びＳＯ₂を示し、ｍ及びｎは、１≦ｍ＋ｎ≦４を満足する。）

（式中、ｍ及びｎは、１≦ｍ＋ｎ≦４を満足する。）

(In the formula, X represents CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , O, S, and SO ₂ , and m and n satisfy 1 ≦ m + n ≦ 4.)

(In the formula, X represents CH ₂ , C (CH ₃ ) ₂ , C (CF ₃ ) ₂ , O, S, and SO ₂ , and m and n satisfy 1 ≦ m + n ≦ 4.)

(In the formula, m and n satisfy 1 ≦ m + n ≦ 4.)

  Moreover, you may contain a polyhydric alcohol unit more than trivalence as an alcohol component. The content of the trihydric or higher polyhydric alcohol unit is not particularly limited, but is preferably 2 mol% or less, more preferably 1.5 mol% or less, and more preferably 1 mol% or less with respect to 100 mol% of all alcohol components. Particularly preferred. When the content of the trihydric or higher polyhydric alcohol unit is within this range, the shrinkage behavior, fluidity, draw-down resistance, polymerization time, etc. tend to be improved. Although it does not restrict | limit especially as a polyhydric alcohol unit more than trivalence, For example, a glycerol unit, a trimethylol propane unit, a pentaerythritol unit, a sorbitol unit etc. are mentioned.

  The intrinsic viscosity [η] of the polyester resin of the present invention is not particularly limited, but is 25 ° C. when dissolved in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 1/1 (mass ratio). It is preferable that the intrinsic viscosity [η] in the range of 0.3 to 1.3 dl / g. Preferably it is 0.4-1.0 dl / g, More preferably, it is 0.5-0.9 dl / g, More preferably, it is 0.6-0.8 dl / g. When the intrinsic viscosity [η] is within this range, the polycondensation reaction is easy, and after the polycondensation reaction, it can be easily cut into chips, excellent in moldability, and excellent in impact resistance and mechanical strength. There is a tendency.

The production method of the polyester resin of the present invention is not particularly limited, and can be produced by a known polymerization method such as a transesterification method or an esterification method.
For example, when the polyester resin of the present invention is produced by an esterification method, first, an acid component such as terephthalic acid and adipic acid and an alcohol component such as ethylene glycol and 1,4-cyclohexanedimethanol are mixed at a molar ratio of 1. : 1.2 to 1: 2.2, preferably 1: 1.2 to 1: 1.6, charged into the reaction vessel and gradually pressurized to about 240 to 265 ° C. while being pressurized with nitrogen. Esterification reaction is performed by heating. Next, a catalyst is added, the pressure is reduced to 0.7 kPa abs or less, the mixture is heated at about 260 to 285 ° C. for about 1 to 5 hours, and a polycondensation reaction is performed. Then, the strand is taken out and cooled with water or the like. A polyester resin can be obtained by cutting into pellets.

Moreover, after making terephthalic acid and ethylene glycol react first, it can also be made to react. For example, first, terephthalic acid and ethylene glycol are charged into a reaction vessel in a molar ratio of 1: 1.2 to 1: 2.2, preferably 1: 1.2 to 1: 1.6, While being pressurized with nitrogen, the esterification reaction is performed by gradually heating to about 240 to 265 ° C. Next, adipic acid, ethylene glycol, and 1,4-cyclohexanedimethanol are added to perform esterification. Next, a catalyst is added, the pressure is reduced to 0.7 kPa abs or less, the mixture is heated at about 260 to 285 ° C. for about 1 to 5 hours, and a polycondensation reaction is performed. Then, the strand is taken out and cooled with water or the like. A polyester resin can also be obtained by cutting into pellets.
Although it does not restrict | limit especially as a catalyst used in this case, Antimony trioxide, germanium dioxide, germanium tetrachloride, dibutyltin oxide, tetrabutoxy titanium etc. are mentioned, In the range of about 20-1000 ppm with respect to all the acid components. Can be used. Further, the heat stabilizer is not particularly limited, and examples thereof include phosphorous acid, phosphoric acid, trimethyl phosphate, triethyl phosphate, phosphonic acid, and the like, and is used in a range of about 20 to 1000 ppm with respect to the total acid component. be able to.

Moreover, the case where a polyester resin is manufactured by the transesterification method will be described. First, a reaction vessel in which an ester-forming derivative of terephthalic acid and ethylene glycol are in a molar ratio of 1: 1.3 to 1: 2.7, preferably 1: 1.3 to 1: 2.5. The transesterification reaction is performed by gradually heating to 150 to 220 ° C. in the presence of a transesterification catalyst such as tetrabutoxytitanium.
Next, adipic acid, ethylene glycol, and 1,4-cyclohexanedimethanol are added to perform esterification. Next, a catalyst is added, the pressure is reduced to 0.7 kPa abs or less, the mixture is heated at about 260 to 285 ° C. for about 1 to 5 hours, and a polycondensation reaction is performed. Then, the strand is taken out and cooled with water or the like. A polyester resin can be obtained by cutting into pellets.

Although it does not restrict | limit especially as a transesterification catalyst used in this case, Zinc acetate, manganese acetate, magnesium acetate, etc. are mentioned, It can use in the range of about 20-1000 ppm with respect to all the acid components.
In addition, the catalyst used in the polycondensation is not particularly limited, but examples include antimony trioxide, germanium dioxide, germanium tetrachloride, dibutyltin oxide, tetrabutoxytitanium, and the like. Can be used in a range. Further, the heat stabilizer is not particularly limited, and examples thereof include phosphorous acid, phosphoric acid, trimethyl phosphate, triethyl phosphate, phosphonic acid, and the like, and is used in a range of about 20 to 1000 ppm with respect to the total acid component. be able to.

The polyester resin of the present invention can be formed into a film by a known method. For example, a method of extruding a polyester resin with an extruder after drying, a method of extruding with a vent type extruder while suppressing a decrease in the degree of polymerization due to hydrolysis, a calendar method, and the like. The shape of the film is, for example, a flat shape or a tube shape, and is not particularly limited.
The unstretched film thus obtained can be made into a shrink film by stretching in at least one direction.

The stretching ratio is not particularly limited, but it is stretched 2 to 7 times, preferably 2.5 to 6 times, more preferably 3 to 5 times in one direction (hereinafter referred to as the main shrinkage direction), and the directions are orthogonal to each other. Stretching in the direction is preferably 1 to 2 times, more preferably 1 to 1.8 times. The former is stretching for imparting heat shrinkability. By stretching in this range, sufficient heat shrinkability can be imparted to the film. The latter is extremely effective in improving the impact resistance and tear resistance of the first stretched film. However, if the stretching exceeds twice, thermal shrinkage also occurs in the orthogonal direction, and the finish tends to deteriorate.
The stretching method is not particularly limited, and known methods such as a roll stretching method, a long gap stretching method, a tenter stretching method, and a tubular stretching method can be used. In any of these methods, stretching may be performed by sequential biaxial stretching, simultaneous biaxial stretching, uniaxial stretching, and combinations thereof. In the biaxial stretching, stretching in the vertical and horizontal directions may be performed simultaneously, or either one may be performed first.

In the stretching step, not only the above stretching ratio but also a temperature not lower than the glass transition temperature (hereinafter referred to as “Tg”) of the polyester resin, for example, about Tg−5 to + 40 ° C., in order to express the preferable characteristics of the present invention. Preheating and stretching are preferred. This temperature range is preferable because the transparency of the film is not deteriorated, the film is not sufficiently thin, and the thickness unevenness is not significantly generated.
Moreover, in the heat setting at the time of extending | stretching, after extending | stretching, for example, it is recommended to pass through a 30-150 degreeC heating zone for about 1 to 30 seconds. In addition, before and after such treatment, either one or both may be stretched up to 70%. In particular, it is preferable to extend in the main contraction direction and relax in the orthogonal direction. Furthermore, you may add the process of cooling, applying a stress to a film, maintaining in an expansion | extension or tension state, or the cooling process after canceling | stretching a tension state.

  The thickness of the polyester film of the present invention is not particularly limited, but a film having a thickness in the range of 5 μm to 1.0 mm is practically used. The practical range is preferably 10 to 800 μm, more preferably 20 to 500 μm, and still more preferably 30 to 300 μm. For example, the heat-shrinkable film for labels is preferably 10 to 200 μm, more preferably 20 to 100 μm, and still more preferably 30 to 60 μm.

By producing the polyester film of the present invention by the above method, the polyester film satisfies the following conditions (I) and (II) in terms of the hot water shrinkage rate and the hot water shrinkage stress.
(I) When immersed in warm water at a temperature of 80 ° C. for 10 seconds,
(I-1) Main contraction rate is 40% or more,
(I-2) The shrinkage rate in the direction orthogonal to the main shrinkage direction is 6% or less,
(I-3) The main shrinkage stress is 5.3 N / mm ² or more.
(II) When immersed in warm water at a temperature of 100 ° C. for 10 seconds,
(II-1) Main shrinkage ratio is 50% or more,
(II-2) The shrinkage rate in the direction orthogonal to the main shrinkage direction is 10% or less,
(II-3) The main shrinkage stress is 4.0 N / mm ² or more.

  When the polyester film of the present invention is (I) immersed in warm water at a temperature of 80 ° C. for 10 seconds, (I-1) has a main shrinkage of 40% or more, and (II) is immersed in warm water at a temperature of 100 ° C. for 10 seconds. (II-1) The main shrinkage ratio needs to be 50% or more. More preferably, the former is 45% or more, further preferably 50% or more, and the latter is more preferably 55% or more, further preferably 60% or more. By being in this range, the heat shrinkage force of the film becomes sufficient, and when the container is shrunk on a container such as a PET bottle, it adheres to the container and the appearance is improved.

  Furthermore, when the polyester film of the present invention is immersed in warm water of (I) temperature 80 ° C. for 10 seconds, (I-2) the shrinkage rate in the direction orthogonal to the main shrinkage direction is 6% or less, and (II) temperature 100 When immersed in warm water of ° C. for 10 seconds, (II-2) the shrinkage rate in the direction orthogonal to the main shrinkage direction needs to be 10% or less. More preferably, the former is 5% or less, and the latter is 9% or less. By being in this range, when coating and shrinking on a container such as a PET bottle, there is little vertical shrinkage and the appearance is good. “Vertical shrinkage” means that the length of the label after shrinkage is not uniform, so that the upper edge of the label after being shrunk on a container such as a PET bottle is drawn downward, This refers to poor appearance, such as drawing a line that curves upward.

Further, when the polyester film of the present invention is (I) immersed in warm water at a temperature of 80 ° C. for 10 seconds, (I-3) main shrinkage stress is 5.3 N / mm ² or more, and (II) hot water at a temperature of 100 ° C. (II-3) The main shrinkage stress needs to be 4.0 N / mm ² or more. More preferably the former is 6.0 N / mm ² or more, more preferably at 6.7 N / mm ² or more, the latter is more preferably 4.7 N / mm ² or more, 5.3 N / mm ² or more is more preferable. By being in this range, the heat shrinkage force of the film becomes sufficient, and when the container is shrunk on a container such as a PET bottle, it adheres to the container and the appearance is improved. Moreover, it is preferable also from the surface of the reinforcement effect of the container after coating shrinkage.

The polyester film of the present invention preferably has a haze of 15 or less per film having a thickness of 50 μm. When the haze of the film exceeds 15 per 50 μm thick film, the transparency of the film is impaired, which is not preferable as a film for a label. The haze of the film is preferably 12 or less, more preferably 10 or less per 50 μm thick film. The haze amount of the film is determined by stretching conditions such as the stretching temperature and stretching ratio of the film, and stretching equipment.
In addition, for the purpose of imparting lubricity to the polyester film of the present invention, it is preferable to add inorganic particles, organic salt particles or crosslinked polymer particles as a lubricant. Inorganic particles include calcium carbonate, kaolin, talc, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, riotium fluoride, etc. Is mentioned. In particular, in order to obtain a film having good handling properties and low haze, the silica particles are preferably aggregated silica particles formed by agglomerating primary particles. Examples of the organic salt particles include terephthalate such as calcium oxalate, calcium, barium, zinc, manganese, and magnesium.

The particle size of the inorganic particles is not particularly limited. For example, the average particle size of silica is preferably 0.5 to 10 μm, more preferably 1 to 8 μm, and still more preferably 1 to 5 μm. By being in this range, the cohesiveness is strong, there is no frequent occurrence of fluff when made into a film, etc., and the particle diameter is too large, and when it is made into a film etc., silica may appear on the surface. There is also a tendency for the lubricity to be good.
The addition amount of the inorganic particles is not particularly limited, but is preferably 0.01 to 0.1% by mass, more preferably 0.03 to 0.08% by mass, from the viewpoint of film transparency. 0.04-0.07 mass% is still more preferable.
The method for adding the inorganic particles is not particularly limited. (1) During the polyester polycondensation step, for example, a method of adding a liquid in which silica is dispersed in ethylene glycol, (2) When producing a polyester film, There are a method of directly blending with a polyester resin, a method (3) of blending a masterbatched polyester resin, and the like. By the above method, it is possible to provide a film having good slipperiness during the film production process and good slippery when used as a label for containers such as PET bottles.

  The polyester film of the present invention may be subjected to various conventionally known processing treatments and may be blended with appropriate additives in order to further impart specific performance. Examples of processing treatments include irradiation with ultraviolet rays, α rays, β rays, γ rays, electron beams, etc .; treatments such as corona treatment, plasma irradiation treatment, flame treatment, etc .; application of resins such as vinylidene chloride, polyvinyl alcohol, polyamide, and polyolefin Or laminating; and metal vapor deposition. Examples of additives include fatty acid metal salts such as calcium stearate, zinc stearate, magnesium stearate, barium stearate, aluminum stearate; resins such as polyether, polyamide, polycarbonate, polyolefin, (meth) acrylic resin; silica Inorganic particles such as talc, kaolin and calcium carbonate; pigments such as titanium oxide and carbon black; other inorganic and organic crystal nucleating agents, hydrolysis-resistant agents, reinforcing agents, fluorescent whitening agents, ultraviolet absorbers, Antioxidants, lubricants, mold release agents, plasticizers, antistatic agents, flame retardants, flame retardant aids, light proofing agents, colorants and the like can be mentioned.

Hereinafter, the present invention will be described in more detail by way of examples. The physical properties in the examples were evaluated by the following methods.
(1) Resin composition About the obtained polyester resin, it analyzed about the resin composition by the pyrolysis chromatography and the high performance liquid chromatography about an alkali decomposition product.
(2) Intrinsic viscosity [η]
The pulverized polyester resin was dissolved in a mixed solvent of phenol / 1,1,2,2-tetrachloroethane = 1/1 (mass ratio) and measured at 25 ° C. using an Ubbelohde viscometer.

(3) Warm water shrinkage The obtained film is adjusted at a temperature of 23 ± 1 ° C. × humidity of 50 ± 10% RH for 24 hours. Next, the sample was cut into a 10 cm × 10 cm square and immersed in warm water at the respective temperatures for 10 seconds under no load to cause heat shrinkage. The length in the horizontal direction (main shrinkage direction) and the vertical direction (direction perpendicular to the main shrinkage direction) of the film after heat shrinkage was measured, and the hot water shrinkage rate was determined according to the following formula.
Hot water shrinkage rate (%) = 100 × (length before shrinkage−length after shrinkage) ÷ (length before shrinkage)
(4) Hot water shrinkage stress Measured using a "heat shrinkage tester" manufactured by Toyo Seiki Co., Ltd. First, the obtained film is adjusted at a temperature of 23 ± 1 ° C. × humidity of 50 ± 10% RH for 24 hours. Next, the film is cut into a strip shape having a length of 8 cm (main shrinkage direction) and a width of 3 cm, and 1 cm and 2 cm marks are put in the length direction. The film was sandwiched between clips (5 cm intervals) and immersed in warm water at each temperature for 10 seconds to cause heat shrinkage, and the shrinkage stress was determined.

(5) Solvent adhesion The obtained film is adjusted at a temperature of 23 ± 1 ° C. × humidity of 50 ± 10% RH for 24 hours. Next, it was cut into a strip of 20 cm (main shrinkage direction) × 5 cm, 5 g / m ^{2 of} THF was applied, and both ends (5 mm width) were quickly joined at room temperature. The joined film was pulled by hand and evaluated in the following three stages.
A: Ten or more of the 11 test pieces were not pulled by hand, and the state of the joint was not wrinkled.
○: 5 to 9 of 11 test pieces were not pulled apart by hand, and the state of the joint was not wrinkled.
X: 4 or less of 11 test pieces were not pulled by hand, and the state of the joint was not wrinkled.
(6) Transparency The obtained film was adjusted at a temperature of 23 ± 1 ° C. × humidity of 50 ± 10% RH for 24 hours, and the haze was measured using a haze meter NDH2000 manufactured by Nippon Denshoku Industries Co., Ltd.

Example 1
A reaction vessel equipped with a stirrer, a thermometer, and a rectifying tower was charged with 226 kg of terephthalic acid as an acid component and 118 kg of ethylene glycol as an alcohol component. While stirring this under nitrogen pressure, the temperature was gradually raised to 260 ° C., and esterification was carried out while distilling off the generated water. Next, 19.7 kg of adipic acid, 16.7 kg of ethylene glycol, and 28.1 kg of 1,4-cyclohexanedimethanol were added for esterification. Next, 0.6 kg of triethyl phosphate (as a 13% by mass ethylene glycol solution) and 12 kg of antimony trioxide (as a 1.5% by mass ethylene glycol solution) were added as a polycondensation catalyst, and then 0.15 kg of silica as a lubricant. (Silicia 310P manufactured by Fuji Silysia Chemical Co., Ltd. as a 7% by mass ethylene glycol dispersion) was added, pressure reduction was started, and finally 285 while distilling ethylene glycol out of the reaction system at 0.04 kPa abs. Polycondensation was performed at 0 ° C., and the polycondensation reaction was stopped when a predetermined stirring torque was reached. Then, it took out in strand form from the discharge outlet provided in the bottom part of reaction container, cooled with water, and cut | disconnected in chip shape with the strand cutter, and obtained polyester resin. The intrinsic viscosity [η] of the obtained polyester resin was 0.75.

  The obtained polyester resin is supplied to a twin-screw extruder for film production, melt-extruded at 260 ° C. while being vacuum-sucked from two vent holes, extruded from a T-shaped die into a sheet, and this is cooled with a cooling roll ( The sheet was wound around a surface temperature of 20 ° C. and solidified by cooling to obtain a sheet having a thickness of about 200 μm. This sheet is preheated to 80 ° C., then stretched 1.05 times in the longitudinal direction, cooled, sent to a tenter-type transverse stretcher, preheated at a temperature of 90 ° C., and 4.75 in the width direction at a temperature of 75 ° C. The film was stretched twice and heat fixed at a temperature of 75 ° C. In the heat treatment part, about 3% relaxation was imparted in the width direction, and the film coming out of the tenter was uniformly cooled to obtain a shrink film having a thickness of 50 μm.

Example 2
Example 1 except that 232.7 kg of terephthalic acid, 122.1 kg of ethylene glycol, 13.1 kg of adipic acid, 11.1 kg of ethylene glycol, and 28 kg of 1,4-cyclohexanedimethanol were added. A polyester resin was obtained in the same manner. The intrinsic viscosity [η] of the obtained polyester resin was 0.73.
A shrink film having a thickness of 50 μm was obtained from the obtained polyester resin in the same manner as in Example 1.

Example 3
Example, except that 239.4 kg of terephthalic acid, 125.4 kg of ethylene glycol, 6.5 kg of adipic acid, 5.5 kg of ethylene glycol, and 27.9 kg of 1,4-cyclohexanedimethanol were added. In the same manner as in Example 1, a polyester resin was obtained. The intrinsic viscosity [η] of the obtained polyester resin was 0.71.
A shrink film having a thickness of 50 μm was obtained from the obtained polyester resin in the same manner as in Example 1.

Example 4
Example, except that 235.5 kg of terephthalic acid, 123.5 kg of ethylene glycol, 13.2 kg of adipic acid, 11.2 kg of ethylene glycol, and 21.7 kg of 1,4-cyclohexanedimethanol were added. In the same manner as in Example 1, a polyester resin was obtained. The intrinsic viscosity [η] of the obtained polyester resin was 0.74.
A shrink film having a thickness of 50 μm was obtained from the obtained polyester resin in the same manner as in Example 1.

Example 5
Polyester as in Example 1 except that 230.9 kg of terephthalic acid, 121.2 kg of ethylene glycol, 13 kg of adipic acid, 11 kg of ethylene glycol, and 32 kg of 1,4-cyclohexanedimethanol were added. A resin was obtained. The intrinsic viscosity [η] of the obtained polyester resin was 0.72.
A shrink film having a thickness of 50 μm was obtained from the obtained polyester resin in the same manner as in Example 1.

Example 6
The polyester resin obtained in the same manner as in Example 3 was supplied to a twin-screw extruder for film production, melt-extruded at 260 ° C. while being vacuumed from two vent holes, and formed into a sheet from a T-die. This was extruded, wound around a cooling roll (surface temperature 20 ° C.), and cooled and solidified to obtain a sheet having a thickness of about 200 μm. This sheet is preheated to 80 ° C., then stretched 1.05 times in the longitudinal direction, cooled, sent to a tenter type transverse stretcher, preheated at a temperature of 90 ° C., and 3.75 in the width direction at a temperature of 75 ° C. The film was stretched 0 times and heat-set at a temperature of 75 ° C. In the heat treatment part, about 3% relaxation was imparted in the width direction, and the film coming out of the tenter was uniformly cooled to obtain a shrink film having a thickness of 50 μm.

Example 7
The polyester resin obtained in the same manner as in Example 3 was supplied to a twin-screw extruder for film production, melt-extruded at 260 ° C. while being vacuumed from two vent holes, and formed into a sheet from a T-die. This was extruded, wound around a cooling roll (surface temperature 20 ° C.), and cooled and solidified to obtain a sheet having a thickness of about 200 μm. This sheet is preheated to 80 ° C., then stretched 1.05 times in the longitudinal direction, cooled, sent to a tenter-type transverse stretcher, preheated at a temperature of 70 ° C., and 4.4 in the width direction at a temperature of 60 ° C. The film was stretched 2 times and heat-fixed at a temperature of 55 ° C. In the heat treatment part, about 3% relaxation was imparted in the width direction, and the film coming out of the tenter was uniformly cooled to obtain a shrink film having a thickness of 50 μm.

Example 8
The polyester resin obtained in the same manner as in Example 3 was supplied to a twin-screw extruder for film production, melt-extruded at 260 ° C. while being vacuumed from two vent holes, and formed into a sheet from a T-die. This was extruded, wound around a cooling roll (surface temperature 20 ° C.), and cooled and solidified to obtain a sheet having a thickness of about 200 μm. This sheet is preheated to 80 ° C., then stretched 1.05 times in the longitudinal direction, cooled, sent to a tenter type transverse stretcher, preheated at a temperature of 100 ° C., and 4.4 in the width direction at a temperature of 100 ° C. The film was stretched twice and heat fixed at a temperature of 100 ° C. In the heat treatment part, about 3% relaxation was imparted in the width direction, and the film coming out of the tenter was uniformly cooled to obtain a shrink film having a thickness of 50 μm.

Comparative Example 1
Example except that 243.9 kg of terephthalic acid, 127.9 kg of ethylene glycol, 2.2 kg of adipic acid, 1.8 kg of ethylene glycol, and 27.8 kg of 1,4-cyclohexanedimethanol were added. In the same manner as in Example 1, a polyester resin was obtained. The intrinsic viscosity [η] of the obtained polyester resin was 0.69.
A shrink film having a thickness of 50 μm was obtained from the obtained polyester resin in the same manner as in Example 1.

Comparative Example 2
Example except that 219.2 kg of terephthalic acid, 114.4 kg of ethylene glycol, 26.3 kg of adipic acid, 22.3 kg of ethylene glycol, and 28.1 kg of 1,4-cyclohexanedimethanol were added. In the same manner as in Example 1, a polyester resin was obtained. The intrinsic viscosity [η] of the obtained polyester resin was 0.78.
A shrink film having a thickness of 50 μm was obtained from the obtained polyester resin in the same manner as in Example 1.

Comparative Example 3
Example 1 with the exception that 228.3 kg of terephthalic acid, 119.8 kg of ethylene glycol, 12.8 kg of adipic acid, 10.9 kg of ethylene glycol, and 38 kg of 1,4-cyclohexanedimethanol were added. A polyester resin was obtained in the same manner. The intrinsic viscosity [η] of the obtained polyester resin was 0.70.
A shrink film having a thickness of 50 μm was obtained from the obtained polyester resin in the same manner as in Example 1.

Comparative Example 4
Example 1 except that 238.3 kg of terephthalic acid, 125 kg of ethylene glycol, 13.4 kg of adipic acid, 11.4 kg of ethylene glycol, and 15.4 kg of 1,4-cyclohexanedimethanol were added. A polyester resin was obtained in the same manner. The intrinsic viscosity [η] of the obtained polyester resin was 0.76.
A shrink film having a thickness of 50 μm was obtained from the obtained polyester resin in the same manner as in Example 1.

Comparative Example 5
3.97 kg of dimethyl terephthalate, 0.44 kg of dimethyl isophthalate, and 2.86 kg of 1,4-butanediol were charged into a reaction vessel equipped with a reflux tower and a stirrer. Butyl lentinate was added, and the reaction was carried out while distilling off the methanol produced as a by-product at a reaction temperature of 140 ° C. to 240 ° C. until the methanol distillate amounted to 90% of the theoretical amount to obtain an esterified product. The esterified product was polymerized to a limiting viscosity of 0.90 dl / g while distilling off the glycol component by-produced at a temperature of 250 ° C. under a high vacuum of 0.6 kPa abs or less, to obtain a polyester resin 1.
Further, 3.26 kg of terephthalic acid, 0.87 kg of isophthalic acid, 0.19 kg of adipic acid and 2.44 kg of ethylene glycol were charged into a reaction vessel equipped with a reflux tower and a stirring device, and the temperature was 200 ° C. to 240 ° C. While distilling off the water produced as a by-product, the reaction was carried out until the amount of distilled water reached 90% of the theoretical amount to obtain an esterified product. Next, 500 ppm of antimony trioxide is added to this esterified product as a catalyst with respect to the raw material charged, and the glycol component by-produced at a temperature of 285 ° C. is distilled off at a high vacuum of 0.6 kPa abs or less, while the intrinsic viscosity is reduced to 0. Polymerization was carried out to 80 dl / g to obtain polyester resin 2.

Also, 3.79 kg of terephthalic acid, 2.12 kg of ethylene glycol, and 1.15 of 1,4-cyclohexanedimethanol were charged into a reaction vessel equipped with a reflux tower and a stirring device, and the temperature was increased from 200 ° C. to 240 ° C. While distilling off the produced water, the reaction was carried out until the distilled amount of water reached 90% of the theoretical amount to obtain an esterified product. Next, 500 ppm of antimony trioxide is added to this esterified product as a catalyst with respect to the raw material charged, and the glycol component by-produced at a temperature of 285 ° C. is distilled off at a high vacuum of 0.6 kPa abs or less, while the intrinsic viscosity is reduced to 0. Polymerization was performed until 85 dl / g was obtained, thereby obtaining a polyester resin 3.
Next, the obtained polyester resins 1, 2, and 3 are dried by vacuum drying until the water content becomes 100 ppm or less, and the blending ratio is set to polyester resin 1/2/3 = 20/30/50, which is melted. Using an extruder, the film was extruded onto a cooling drum (20 ° C.) at a temperature of 260 ° C. to obtain a film original. The obtained film raw material is stretched at a temperature of 85 ° C., which is 15 ° C. to 20 ° C. higher than the Tg of the polyester forming the film raw material, in a direction perpendicular to the film forming direction of the raw material. The film was stretched 4.0 times (the film forming direction was 1.0 times) to obtain a shrink film having a thickness of 50 μm.

表１、２から明らかなように、本発明のポリエステル樹脂およびポリエステルフィルムは、ＰＥＴボトル等に被覆収縮させるに良好な収縮特性を有し、また優れた溶剤接着性を示した。

As is clear from Tables 1 and 2, the polyester resin and polyester film of the present invention had good shrinkage properties for coating shrinkage on PET bottles and the like, and exhibited excellent solvent adhesion.

Claims (4)

  A polyester resin comprising an acid component containing 3 to 9 mol% adipic acid units and an alcohol component containing 10 to 15 mol% 1,4-cyclohexanedimethanol units.   A polyester film containing the polyester resin according to claim 1.   The polyester film according to claim 2, wherein the polyester film is stretched in at least one direction. The polyester film according to claim 3, wherein the hot water shrinkage rate and the hot water shrinkage stress satisfy the following conditions (I) and (II).
(I) When immersed in warm water at a temperature of 80 ° C. for 10 seconds,
(I-1) Main contraction rate is 40% or more,
(I-2) The shrinkage rate in the direction orthogonal to the main shrinkage direction is 6% or less,
(I-3) The main shrinkage stress is 5.3 N / mm ² or more.
(II) When immersed in warm water at a temperature of 100 ° C. for 10 seconds,
(II-1) Main shrinkage ratio is 50% or more,
(II-2) The shrinkage rate in the direction orthogonal to the main shrinkage direction is 10% or less,
(II-3) The main shrinkage stress is 4.0 N / mm ² or more.