TWI602684B - Heat-shrinkable polyester-based film - Google Patents

Description

Heat shrinkable polyester film

The present invention relates to a heat-shrinkable polyester film which is also suitable for use as a label.

A heat-shrinkable plastic film having a property of shrinking due to heating is widely used for applications such as packaging, labeling, and sealing. An extended film such as a polyvinyl chloride film, a polystyrene film, or a polyester film is known as a heat shrinkable plastic film, and these films are used for polyethylene terephthalate (PET). The use of labels, lids, and collective packaging for various containers such as containers, polyethylene containers, and glass containers.

As described above, various plastic films have been used as heat-shrinkable films, but polyvinyl chloride-based films have a problem of low heat resistance and when they are incinerated, they constitute hydrogen chloride gas or dioxin. Reasons such as environmental suitability. Further, when a container such as a PET container to which a label of a polyvinyl chloride film is attached is recycled, there is a problem that the label must be separated from the container.

As for the polystyrene film, although the processability after shrinkage is good, since the solvent resistance is lacking, it is necessary to use a special composition ink when printing is to be applied to the film surface. In addition, when a polystyrene film is applied to a label of a hot drink PET bottle, when the label comes into contact with a hot wire for warming equipment such as a warmer used for storing the bottle, the label will soon be The problem of instantaneous melting and heat resistance. In addition, as for the problem of the polystyrene film, the transparency required for the excellent image of the product is low (when the polystyrene film is shrunk by hot air, devitrification is likely to occur), and the treatment is not improved. The incineration temperature required is not required, and a large amount of black smoke and odor generated during incineration.

The polyester-based film is used as a label for a container, such as a polyvinyl chloride-based film or a polystyrene-based film, which is improved in heat resistance, environmental suitability, solvent resistance, and the like (see, for example, , Patent Document 1).

However, the polyester film is required to further improve its shrinkage characteristics, and the first characteristic that I want to improve is to inhibit the labeling (film) whitening of the film when the label is attached to the container due to heat shrinkage (whitening). )phenomenon. This whitening phenomenon is likely to occur particularly when the film is heated and shrunk by dry heat such as hot air, and tends to occur in a film having a high heat shrinkage rate. Moreover, the occurrence of whitening tends to deteriorate over time. Although a low heat shrinkage film can be selected to avoid label whitening, the amount of heat necessary to shrink the film will increase, especially for containers with low heat resistance, and label-to-container adhesion. The problem is reduced when the heat-expanded container is retracted to its original size due to shrinkage. Since the container has been thinned due to the reduction in the use amount of the container material in the background of the resource reduction in recent years, and the heat resistance of the container is also lowered, it is easy to cause damage to the container as described above. Reduce the tightness. Therefore, instead of selecting a film having a low heat shrinkage rate, a film having a high heat shrinkage rate and suppressing the occurrence of whitening is desired.

In addition, the second characteristic that is desired for the polyester film suppresses the occurrence of shrinkage unevenness, and the third characteristic suppresses the jump-up movement of the label (which means that the label is randomly installed by any means when the label is attached to the container) The position moves toward the upper end of the container axis). At the same time as the first characteristic as described above, the second and third characteristics are characteristics that the label is mounted in the container to have an excellent appearance. The shrinkage unevenness is likely to occur particularly when the film is heated and shrunk by dry heat such as hot air, and the film is likely to be generated when, for example, the film is rapidly thermally contracted. The jump movement on the label is likely to occur when the film having a high heat shrinkage rate in a direction orthogonal to the main shrinkage direction is heated and shrunk. Since either case affects the aesthetics of the product, it is desirable to have a film that does not undergo uneven or jump-up movement when contracted.

Further, since the conventional polyester film is an insulator, the film thereof has a problem that static electricity easily occurs and ‧ is accumulated. Therefore, for example, in the film manufacturing process, the printing of the film, the adhesion of the film to each other, etc., the film may be caused to wrap around the film or the static electricity generated by the sensing potential of the human body, which is important to make the use convenience of the film tend to be complicated. factor. Further, the static electricity constitutes a so-called printing whisker, a surface of a contaminated film, etc., so that it is likely to cause a decrease in the value of the commodity. Therefore, a polyester-based film in which the occurrence of static electricity and the accumulation of the static electricity have been suppressed is desired.

Further, at present, a heat-shrinkable film (heat shrinkable label) which is processed into a cylindrical shape after application of a printing process as needed is used to cover the peripheral surface of the container, and then the film is heat-shrinked to coat the periphery of the container. As a method of attaching the label to the container, the method of processing the heat-shrinkable film into a cylindrical shape may be a method of applying a solvent to one side of the film, and attaching the coated surface to the opposite side of the film to adhere thereto. The method of the two sides of the film. However, depending on the composition of the polyester film, there is a possibility that the adhesion at both ends of the film is insufficient. If the adhesiveness is insufficient, that is, when the adhesive strength is insufficient, during the heat shrinking process or when the container is used, there is a possibility that the label which is once the container is installed is about to be peeled off. Therefore, a heat shrinkable label having sufficient adhesion as described above is desired.

(Patent Document 1) Japanese Patent Laid-Open Publication No. 2002-46177

Further, when the content of the beverage or the like filled in the container is high, there is a possibility that adhesion between the heat-shrinkable films (heat-shrinkable labels) attached to the container occurs between adjacent containers. Generally, in order to prevent an electrostatic-induced trouble during processing including printing, an antistatic agent is applied to the film, and the antistatic agent has a heat-resistant adhesive effect. However, after the container is filled with the high-temperature contents, it is necessary to cool the hot water sprayed on the container, and as a result, the antistatic agent coated on the surface of the film will be washed away by hot water, so that it may cause substantial However, the heat-resistant adhesive effect cannot be obtained.

In view of the above problems, the present invention has an object of providing a heat-shrinkable polyester film having a high heat shrinkage rate and suppressing occurrence of whitening caused by heat shrinkage. A more preferable mode is to provide a heat-shrinkable polyester film which suppresses the occurrence of a malfunction caused by static electricity, or a heat-shrinkable polyester film which has been suppressed from occurring at a high temperature, and provides a heat-shrinkable polyester film. A heat-shrinkable polyester film suitable for label use of a container is a technical problem.

That is, the heat-shrinkable polyester film according to the present invention is constituted by the following constitution.

A heat-shrinkable polyester film characterized by having a heat shrinkage ratio of 30 to 60% in a main shrinkage direction when immersed in hot water of 95 ± 0.5 ° C for 10 seconds, and at 59.5 to When immersed in hot water at any temperature of 90.5 ° C and at any temperature of ±0.5 ° C for 10 seconds, the length in the direction orthogonal to the main shrinkage direction will be elongated.

2. The heat-shrinkable polyester film according to Item 1, wherein the anionic antistatic agent is present on at least one side.

3. The heat-shrinkable polyester film according to Item 2, wherein the anionic antistatic agent has an alkyl group and has a carbon number of 10 to 20.

4. The heat-shrinkable polyester film according to Item 1, wherein a polyester system obtained by grafting at least one radical polymerizable monomer to a hydrophobic copolymerized polyester is provided on at least one side of the film. An improved layer of blocking resistance of the grafted copolymer.

5. The heat-shrinkable polyester film according to Item 4, wherein the radically polymerizable single system contains at least maleic anhydride and styrene.

6. The heat-shrinkable polyester film according to Item 1, wherein the at least one side of the film comprises grafting at least one radical polymerizable monomer An anti-blocking improving layer of a polyester-based graft copolymer obtained by hydrophobic copolymerizing a polyester, and an anionic antistatic agent is present in the anti-blocking improving layer.

7. The heat-shrinkable polyester film according to item 6, wherein the radically polymerizable single system contains at least maleic anhydride and styrene.

8. The heat-shrinkable polyester film according to item 6, wherein the anionic antistatic agent has an alkyl group and has a carbon number of 10 to 20.

The heat-shrinkable polyester film according to any one of the preceding claims, wherein the main shrinkage is immersed in hot water of 80 ± 0.5 ° C for 10 seconds. The direction of thermal shrinkage is less than 40%.

The heat-shrinkable polyester film according to any one of the first aspect, wherein the heat shrinkage in the main shrinkage direction is started when immersed in hot water, and the hot water The impregnation system is any one of the following: 60±0.5°C, 65±0.5°C, 70±0.5°C, 75±0.5°C, 80±0.5°C, 85±0.5°C, 90±0.5°C, and 95±0.5°C heat. The water is immersed for 10 seconds, and is subtracted from the heat shrinkage rate in the main shrinkage direction (the temperature at which the heat shrinkage rate in the main shrinkage direction exceeds 0% + 10 ° C) [(the heat shrinkage ratio in the main shrinkage direction) The heat shrinkage rate in the main shrinkage direction of more than 0% of the temperature - 5 ° C) is less than 20%.

The heat-shrinkable polyester film according to any one of the first aspect, wherein the haze of the heat-shrinkable polyester film after heat shrinkage is 10% or less.

12. The heat shrinkage according to any one of the first, second, fourth, and sixth A polyester film which can be adhered to a non-chlorine-based organic solvent.

A heat-shrinkable label, which is produced by using the heat-shrinkable polyester film according to any one of the first, second, fourth, and sixth aspects.

The heat-shrinkable polyester film according to the present invention preferably has a heat shrinkage ratio of 30 to 60% in the main shrinkage direction when immersed in hot water of 95 ± 0.5 ° C for 10 seconds, and is 59.5 to 90.5 ° C. When immersed in hot water at any temperature of [a certain temperature ± 0.5 ° C] for 10 seconds, the length in the direction orthogonal to the main shrinkage direction is elongated. The heat shrinkage rate in the main shrinkage direction as described above is preferably less than 40% when immersed in hot water of 80 ± 0.5 ° C for 10 seconds.

In the film relating to the present invention as described above, the so-called "main shrinkage direction" means the direction of maximum shrinkage of the sample film, and if a film of a square is used as a sample, the longitudinal direction or the transverse direction of the square is used. To shrink the direction. The so-called "heat shrinkage rate" is obtained by immersing the sample film in a non-load state in hot water, immersing it in water at 25 ° C for 10 seconds, and then pulling it up, and before the hot water is immersed (before shrinkage) and at 25 ° C. The sample film size after water immersion (after shrinkage) is calculated by the following formula (1). In addition, the so-called "59.5 to 90.5 ° C and any temperature of [certain temperature ± 0.5 ° C]" is selected from, for example, 60 ± 0.5 ° C, 65 ± 0.5 ° C, 70 ± 0.5 ° C, 75 ± 0.5 ° C, 80 ± 0.5 Temperature of any one or two of °C, 85±0.5°C, and 90±0.5°C: Formula (1): heat shrinkage ratio (%) = 100 × (length before shrinkage - length after shrinkage) ÷ (length before shrinkage).

The film relating to the present invention as described above is preferably such that the heat shrinkage in the main shrinkage direction is started when immersed in hot water, and the impregnation system in hot water Any of the following: 60±0.5°C, 65±0.5°C, 70±0.5°C, 75±0.5°C, 80±0.5°C, 85±0.5°C, 90±0.5°C, and 95±0.5°C in hot water for a duration of immersion 10 seconds, minus the heat shrinkage rate in the main shrinkage direction of [(the heat shrinkage rate in the main shrinkage direction is more than 0% + 10 ° C)] [(the heat shrinkage rate in the main shrinkage direction is more than 0%) The heat shrinkage rate in the main shrinkage direction of -5 ° C) is less than 20%.

The film relating to the present invention as described above preferably has a haze of 10% or less after heat shrinkage. The so-called "haze after heat shrinkage" is measured by the method described below. A heat-shrinkable polyester film obtained by storing it in an atmosphere having a temperature of 30 ° C and a relative humidity of 85% for 4 weeks, and using a tubular shape having a diameter of 11 cm which is formed into a radial direction in the main contraction direction is used. The haze of the film after the heat shrinkage can be measured by the method described below. A cylindrical glass bottle (diameter: 6.6 cm) having a temperature of 40 ° C was placed in the tubular film, and hot air of 150 ° C (wind speed of 10 m / s) was blown toward the film for 13 seconds, and then cut by hot air. The film (the number of tubular film samples was 10) was used as a film sample after heat shrinkage. Then, the haze of the film after heat shrinkage was measured in accordance with the guidelines of JIS K7136, and the average value thereof was the haze after heat shrinkage.

The heat-shrinkable polyester film according to the present invention can also be used for the tubular heat-shrinkable label of the label used for a container such as a beverage, and the adhesive property between the shrinkage property of the heat-shrinkable label and the film using the solvent. In the case of coexistence and consideration of the problem or safety of the solvent to the environment, it is preferred that the film relating to the present invention be adhered to a non-chlorine-based organic solvent.

The heat-shrinkable polyester film of the present invention may be a mode in which an anionic antistatic agent is present on at least one side of the film. The anionic antistatic agent is preferably one having an alkyl group and having a carbon number of 10 to 20.

The heat-shrinkable polyester film of the present invention preferably comprises a polyester-based graft copolymer obtained by grafting at least one radical polymerizable monomer to a hydrophobic copolymerized polyester on at least one side of the film. The anti-adhesion layer is improved.

Further, in the present invention, it is preferred that the radically polymerizable single system contains at least maleic anhydride and styrene as described above.

The heat-shrinkable polyester film of the present invention is suitably used as a label, a package, etc., and is not only shrinkable by water vapor, but also has excellent heat even when it is shrunk by hot air. The shrinkage property suppresses the occurrence of whitening upon application of the heat shrinkage treatment, and suppresses wrinkles caused by heat shrinkage, end folding into the interior, and jump jump.

Further, in the mode in which the anionic antistatic agent is present on the surface of the heat-shrinkable polyester film, the surface specific resistance of the film can be suppressed since it is not blended into the film to suppress the occurrence of malfunction due to static electricity.

Further, in the mode in which the anti-blocking modified layer is provided on at least one side of the film, a heat-shrinkable polyester film which is suppressed from occurring at a high temperature can be obtained. The anti-blocking modified layer may also contain an anionic antistatic agent or both.

[Best Embodiment of the Invention]

The heat-shrinkable polyester film according to the present invention preferably has a heat shrinkage ratio of 30 to 60% in a main shrinkage direction when immersed in hot water of 95 ± 0.5 ° C for 10 seconds, and the heat shrinkage ratio is 30% to 60%. It is preferably 35 to 57%, more preferably 40 to 55%. If the film having a heat shrinkage ratio of less than 30% is insufficient in heat shrinkage rate, when the film is used as, for example, a label, the label cannot be attached to the container. Even when a high heat is applied to a film having a shrinkage ratio of less than 30% to cause it to shrink, there is a risk of causing thermal damage to the container, and at the same time, it may cause label looseness due to thermal deformation of the container. On the other hand, in a film having a heat shrinkage ratio of more than 60%, whitening due to heat shrinkage, uneven shrinkage due to sharp shrinkage, deformation of a printed pattern at the time of printing, and unevenness of processing of the upper portion of the label are likely to occur.

The heat shrinkage rate in the main shrinkage direction of the film of the present invention when immersed in hot water of 80 ± 0.5 ° C is preferably less than 40%. When the heat shrinkage ratio exceeds 40%, there is a possibility that the shrinkage is likely to occur rapidly, and the transparency of the film is lowered due to uneven shrinkage or whitening.

Further, the film of the present invention preferably starts when the heat shrinkage in the main shrinkage direction is immersed in hot water, and the dipping in the hot water is any one of the following: 60 ± 0.5 ° C, 65 ± 0.5 ° C, 70 ± 0.5 Immersion in hot water at °C, 75±0.5°C, 80±0.5°C, 85±0.5°C, 90±0.5°C, and 95±0.5°C for 10 seconds, and from [(the main shrinkage direction of the heat shrinkage rate exceeds The heat shrinkage rate in the main shrinkage direction of 0% of temperature + 10 ° C) is obtained by subtracting [the heat shrinkage rate in the main shrinkage direction of the heat shrinkage rate in the main shrinkage direction of more than 0% - 5 ° C) The value is less than 20%. If the value exceeds 20%, there is a possibility that the film is likely to cause a sharp shrinkage and the film is not uniformly colored or whitened to reduce the transparency of the film.

The heat-shrinkable polyester film of the present invention is characterized by: The heat shrinkage rate in the main shrinkage direction is also immersed in hot water at any temperature of 59.5 to 90.5 ° C and at any temperature of ±0.5 ° C for 10 seconds, and the length in the direction orthogonal to the main shrinkage direction will be Will stretch. The elongation which occurs in the orthogonal direction means that the polyester film of the present invention is suitably used as a label member for containers. In other words, the polyester-based film of the present invention is a cylindrical heat-shrinkable label having a radial direction as a main contraction direction and an axial direction perpendicular to the main shrinkage direction of the film, which is caused by shrinkage of the label in the radial direction. Before being fixed to the container, the axial direction will be elongated or become smaller in the axial direction. Therefore, it is possible to suppress the unevenness of the processing result at the upper end of the label, and to easily cause the upper and lower mountain-shaped axes starting from the back processing portion. Direction pull-in phenomenon.

The elongation in the orthogonal direction as described above is carried out by immersing the sample film in an unloaded state in hot water, immediately after immersing in water at 25 ° C for 10 seconds, and then calculating the above formula (1). The size of the sample film before (after shrinking) hot water and after immersion in water at 25 ° C (after shrinkage) can be confirmed. If the value calculated at this time is a negative value, it means that the elongation in the orthogonal direction occurs.

In addition, as long as the elongation as described above occurs at any temperature of 59.5 to 90.5 ° C and meets the conditions of [certain temperature ± 0.5 ° C], the thermal shrinkage in the orthogonal direction of any of the temperatures is within 3%. (preferably within 2%) also meets the film conditions associated with the present invention.

The elongation as described above may be 0% or less as measured in the same manner as the heat shrinkage ratio, but is preferably -0.5% or less. Further, the elongation preferably occurs when immersed in hot water of 80 ± 0.5 ° C and 85 ± 0.5 ° C for 10 seconds.

The haze after heat shrinkage of the film according to the present invention is usually 10% or less, preferably 9.7% or less, more preferably 9.5% or less.

The thickness of the film associated with the present invention is preferably from 20 to 100 μm, more preferably from 30 to 60 μms.

In the film relating to the present invention, it is preferred that the films are adhered to each other with a solvent. The phrase "solvent-adhesive" means that the solvent adhesion strength measured by the "solvent adhesiveness" evaluation method in the examples described later is 3 N/15 mm or more. When the film according to the present invention is used as a label for a container, it is necessary to form the film into a cylindrical shape such as a cylindrical shape, and it is necessary to use a solvent in order to form a cylindrical shape. That is, a solvent is used in order to bond the both end portions of the film so that the main shrinkage direction thereof is the radial direction to produce a thermoplastic tubular film (thermoplastic label). Further, the adhesion of the films to each other is achieved by applying a solvent to one end of one end of the film, and crimping the coated surface to the surface of the other film end, and the resulting thermoplastic label is usually Cut it to the required length.

Examples of the solvent used in the adhesive film include "aromatic hydrocarbons" such as benzene, toluene, xylene, and trimethylbenzene; "halogenated hydrocarbons" such as dichloromethane and chloroform; and "phenols" such as phenol. An organic solvent such as "furan" such as tetrahydrofuran or "oxolane" such as 1,3-dioxane. When it is considered that a toxic substance derived from a halogen such as a chlorine atom is generated, a non-chlorine organic solvent is preferred, and tetrahydrofuran and 1,3-dioxane are preferred from the viewpoint of safety. .

The "dicarboxylic acid component" for constituting the polyester includes an aromatic dicarboxylic acid, an ester of an aromatic dicarboxylic acid, and an aliphatic dicarboxylic acid. More specifically, the "aromatic dicarboxylic acid" system includes: terephthalic acid, isophthalic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-2,6-dicarboxylic acid, sodium 5-sulfonate isophthalate; The "ester of an aromatic dicarboxylic acid" includes a dialkyl ester or a diaryl ester of an aromatic dicarboxylic acid specifically exemplified as described above; and the "aliphatic dicarboxylic acid" includes a dimer acid and a pentane. Diacid, adipic acid, sebacic acid, sebacic acid, oxalic acid, succinic acid. Further, an oxycarboxylic acid such as p-oxybenzoic acid or a ternary or higher carboxylic acid such as trimellitic anhydride or pyromellitic anhydride may be used as a carboxylic acid component for constituting the polyester, if necessary.

The "polyol component" used to form the polyester includes glycols, triols, and the like. The "diol" includes, for example, ethylene glycol, diethylene glycol, 1,3-propanediol, triethylene glycol, 1,4-butanediol, neopentyl glycol, 1,4-cyclohexanedimethanol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-methyl-1,5-pentanediol, 2,2-diethyl-1,3-propanediol, 1, An alkylene glycol such as 9-nonanediol or 1,10-decanediol; an alkylene oxide of polyoxytetramethylene glycol, polyethylene glycol, a bisphenol compound or a derivative thereof An "ether diol" such as an adduct; and a dimer diol. Further, the "triol" includes, for example, "alkyl triol" such as trimethylolpropane, glycerin or neopentyl alcohol. Among the polyol components as exemplified above, neopentyl glycol or 1,4-cyclohexanedimethanol is a useful component required for realizing amorphization and high heat shrinkability of the film, and neopentyl glycol. And the amount of 1,4-cyclohexanedimethanol or the like is 5 to 40 mol%, preferably 10 to 35 mol%, if the total diol is 100 mol%, and further consideration is given to the film. In the case of solvent adhesion, it is more preferably from 18 to 40 mol%, still more preferably from 20 to 35 mol%. Further, although 1,4-butanediol, 1,3-propanediol or the like is useful for lowering the glass transition temperature of the film and exhibiting heat shrinkage in a low temperature region, if it is excessive, it may be low. The temperature region is abruptly thermally contracted, and the shrinkage processing effect and the transparency after shrinkage are deteriorated. Therefore, the amount of 1,4-butanediol or the like should be appropriately set.

Assuming that a unit derived from an acid component and a unit derived from a polyol component of a repeating constituent unit of a polyester produced by condensation of a carboxylic acid and a polyol are regarded as "units", the present invention The related polyester film has one or more selected from the group consisting of ethylene glycol and terephthalic acid which are capable of achieving superior heat shrinkage characteristics, inhibiting the occurrence of whitening, and excellent adhesion by a solvent. Ethylene phthalate unit), a unit composed of neopentyl glycol and terephthalic acid (neopentylene terephthalate unit), 1,4-cyclohexanedimethanol and para-benzene a unit composed of dicarboxylic acid (1,4-cyclohexanedimethanol terephthalate unit), a unit composed of 1,4-butanediol and terephthalic acid (butylene terephthalate) Unit), a unit composed of propylene glycol and terephthalic acid (propylene terephthalate unit), a unit composed of ethylene glycol and terephthalic acid (ethylene terephthalate unit), etc. unit. From the viewpoints of the tear resistance, the heat resistance, the shrinkage finishing, and the increase in the stress at the drop point, the adhesion to the container, the cost, etc., The ethylene glycol formate unit is the main constituent unit of all polyesters. The amount of the ethylene terephthalate unit in all the polyesters is 60% by mole or more, preferably less than 72% by mole, and preferably 70% by mole or less. . When it is less than 72 mol%, it has excellent solvent adhesiveness, and when it is 70 mol% or less, an appropriate shrinkage rate can be obtained.

Preferably, the film contains any combination of the following units. The combination is a polyethylene terephthalate unit, a neopentyl terephthalate unit or a 1,4-cyclohexane dimethanol terephthalate unit, and a butylene terephthalate unit. Or a propylene terephthalate unit. The molar ratio in the combination may be a polyethylene terephthalate unit: neopentyl terephthalate unit or 1,4-cyclohexane dimethanol terephthalate unit: terephthalic acid Butylene formate unit or propylene terephthalate unit = (60 to 72): (5 to 40): (9 to 15). The analysis of the unit content can be carried out using, for example, ¹ H-NMR (nuclear magnetic resonance).

In the polyester for constituting the film, one or two or more selected from the group consisting of inorganic particles, organic salt particles, and crosslinked polymer particles may be added as a lubricant. "Inorganic particles" which can be used as "lubricants" include: calcium carbonate, kaolin, talc, magnesium carbonate, barium carbonate, calcium sulfate, barium sulfate, lithium phosphate, calcium phosphate, magnesium phosphate, aluminum oxide, barium oxide, titanium oxide. Zirconium oxide or lithium fluoride. However, when the ceria particles of the aggregate formed by the primary particles are selected, a film having good workability and low haze can be obtained. The "organic salt particles" include, for example, terephthalic acid salts such as calcium oxalate, calcium, barium, zinc, manganese, and magnesium. Further, the "crosslinked polymer particles" include, for example, one or two or more kinds of copolymers selected from vinyl monomers such as divinylbenzene, styrene, and (meth)acrylic acid; polytetrafluoroethylene; Ethylene; benzoguanamine resin; thermosetting urea resin; thermosetting phenol resin.

Further, in the polyester, an ultraviolet absorber, an antistatic agent, a colorant, an antibacterial agent, or the like may be contained as needed.

A preferred mode of the film relating to the present invention is one in which at least one side (preferably two sides) of the anionic antistatic agent is present on the surface thereof. When an anionic antistatic agent is contained in a film raw material by a method such as blending, and an anionic antistatic agent leaks from the inside of the film to the surface, generation and accumulation of static electricity can be suppressed. However, since the glass transition temperature of the polyester used to constitute the film is usually high, the anionic antistatic agent is likely to not easily leak out of the surface of the film at a temperature at or near normal temperature, so that static electricity cannot be sufficiently suppressed. The tendency to occur and save. Further, the film forming temperature of the film relating to the present invention produced by stretching the resin is high, and the reactivity of the polar group possessed by the polyester is also high, if the antistatic agent is mixed in the film raw material. In the case of film formation, the deterioration of the polyester is promoted, and therefore, the physical properties of the film may be lowered or the coloring may occur.

By adjusting the amount of the antistatic agent, it is possible to suppress the occurrence of a malfunction caused by static electricity, and the degree of such suppression can be known from the surface specific resistance value of the film. In order to sufficiently suppress the occurrence of a failure due to static electricity, the surface specific resistance of the film may be 13 log Ω or less, and preferably 12 log Ω or less. On the other hand, although the lower limit of the surface specific resistance value is not particularly limited, it may be 81 ogΩ or more in practice, and may be an anionic resistance set on the surface of the film required for the surface specific resistance value as described above. The content of the electrostatic agent is preferably from 0.001 to 0.5 g/m ² . When the content of the anionic antistatic agent is less than the above range, there is a possibility that the antistatic effect cannot be sufficiently ensured. On the contrary, if the content of the anionic antistatic agent exceeds the range as described above, there is a possibility that the transparency or the blocking resistance of the film is lowered.

The anionic antistatic agent as described above preferably has an alkyl group and has a carbon number of 10 to 20. When such an antistatic agent is used, for example, in the secondary processing for producing a film or a film, even if it is scattered due to heat, the phenomenon of scattering or the like can be suppressed. Further, when the carbon number is more than 20, the antistatic effect of the antistatic agent itself is insufficient. More preferred anionic antistatic agents are those having a carbon number of from 12 to 18.

The "anionic antistatic agent" in the present invention can be selected from the conventional antistatic agent, that is, it can be selected from the group consisting of higher alcohol sulfate salts, alkylphenol-ethylene oxide adduct sulfate salts, and alkyl groups. "Sulfuric acid and sulfonic acid derivatives" such as sulfonates and alkyl allyl sulfonates. More specifically, it includes: an alkyl sulfonate, an alkyl benzene sulfonate, an alkyl sulfate, an alkyl ethoxy sulfate, an alkyl phosphate. Preferred "anionic antistatic agents" include, for example, dodecylsulfonate and dodecylbenzenesulfonate.

In the heat-shrinkable polyester film of the present invention, a polyester-based graft copolymerization obtained by grafting at least one radical polymerizable monomer to a hydrophobic copolymerized polyester on at least one side of the film It is also preferred that the heat-shrinkable polyester film of the anti-adhesion improving layer of the article is implemented. Hereinafter, the heat-shrinkable polyester film will be described.

(radical polymerizable monomer)

The radical polymerizable monomer used in the present invention is preferably a radical polymerizable monomer containing a hydrophilic radical polymerizable monomer as an essential component. The reason for this is that the dispersion of the aqueous solvent of the polyester-based graft copolymer can be used to form the anti-blocking improving layer of the present invention (details will be described later).

The "hydrophilic radical polymerizable monomer" means a radical polymerizable monomer having a hydrophilic group or a group which can be changed to a hydrophilic group later. The radically polymerizable single system having a hydrophilic group includes a radical polymerizable monomer containing a carboxyl group, a hydroxyl group, a phosphoric acid group, a phosphorous acid group, a sulfonic acid group, a phosphonium group, a fourth-order ammonium salt group or the like. The radically polymerizable single system having a group which can be changed to a hydrophilic group includes a radical polymerizable monomer containing an acid anhydride group, a glycidyl group, a chlorine group or the like.

Specifically, it includes: fumarate and its anhydride, monoethyl fumarate, diethyl fumarate, dibutyl fumarate, etc. "monoester or diester of diacid"; maleic acid and its anhydride, monoethyl maleate, diethyl maleate, dibutyl maleate, etc. "Isoester or diester of butylene diacid"; itaconic acid and its anhydride, ester or diester of itaconic acid; "m-butyleneimine" such as phenyl maleimide "Styrene derivative" such as styrene, α-methylstyrene, tert-butylstyrene or chloromethylstyrene; vinyltoluene, divinylbenzene, and the like.

In addition, it may also include: alkyl acrylate, alkyl methacrylate (alkyl is methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, 2 -ethylhexyl, cyclohexyl, phenyl, benzyl, phenylethyl, etc.); 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-methacrylic acid 2- "hydroxyl-containing acrylic monomer" such as hydroxypropyl ester; acrylamide, methacrylamide, N-methylmethacrylamide, N-methyl acrylamide, N-methylol propylene oxime Amine, N-methylol methacrylamide, N,N-dimethylol decylamine, N-methoxymethyl propylene decylamine, N-methoxymethyl methacrylamide, N -Phenyl acrylamide, etc. "Acetyl group-containing acrylic monomer"; N,N-diethylaminoethyl acrylate, N,N-diethylaminoethyl methacrylate, etc. "Amino group-containing acrylic monomer"; "epoxy group-containing acrylic monomer" such as glycidyl acrylate or glycidyl methacrylate; acrylic acid, methacrylic acid, and the like (sodium salt) , "Acrylic monomer containing a carboxyl group or a salt thereof" such as a potassium salt or an ammonium salt.

The hydrophilic radically polymerizable single system as described above may be used singly or in combination of two or more kinds thereof.

Among these, the hydrophilic group is preferably a carboxyl group because the water dispersibility of the polyester-based graft copolymer and the acid value tend to be suitable (described later). Therefore, the hydrophilic radical polymerizable monomer is preferably a radical polymerizable monomer having a carboxyl group or a group which generates a carboxyl group, and includes, for example, maleic anhydride and an ester thereof.

In the present invention, the radical polymerizable monomer preferably contains at least maleic anhydride and styrene.

(hydrophobic copolymerized polyester)

The "hydrophobic copolymerized polyester" used in the present invention is preferably a water-insoluble polyester which is inherently not dispersed or dissolved in water. When it is used as a backbone polymer in the case of graft polymerization of a polyester which is to be dispersed or dissolved in water, it is excellent in water resistance.

The "hydrophobic copolymerized polyester" is obtained by having an ester bond in a main chain or a side chain and polycondensing a polyvalent carboxylic acid and a glycol. The polycarboxylic acid component for constituting the hydrophobic copolymerized polyester may be an aromatic, aliphatic or alicyclic dicarboxylic acid, or a dicarboxylic acid containing a radical polymerizable double bond or a ternary or higher polycarboxylic acid. An acid, or an ester derivative of this type.

The "aromatic dicarboxylic acid" includes terephthalic acid, isophthalic acid, phthalic acid, naphthalene dicarboxylic acid, and diphenyl phthalic acid. The "ester derivative of an aromatic dicarboxylic acid" includes a dialkyl ester or a diaryl ester of an aromatic dicarboxylic acid specifically exemplified as described above. The dicarboxylic acid containing a hydrophilic group such as sodium 5-sulfonate isophthalate is preferably not used because it reduces water resistance.

The "aliphatic dicarboxylic acid" includes succinic acid, adipic acid, sebacic acid, sebacic acid, dodecanedioic acid, dimer acid and the like.

The "alicyclic dicarboxylic acid" includes 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, an anhydride thereof, and the like.

The "dicarboxylic acid containing a radically polymerizable double bond" includes "α, β-unsaturation of fumaric acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, etc." "Dicarboxylic acid"; "alicyclic dicarboxylic acid containing a radical polymerizable double bond" such as 2,5-norbornene dicarboxylic anhydride or tetrahydrophthalic anhydride. From the viewpoint of polymerizability, fumaric acid, maleic acid, and 2,5-norbornene dicarboxylic acid are preferred.

The "hydrophobic copolymerized polyester" used in the present invention is preferably in an amount of 100 mol% of the dicarboxylic acid component, 60 to 99.5 mol% of the aromatic dicarboxylic acid, an aliphatic dicarboxylic acid and/or an alicyclic ring. The dicarboxylic acid of the group is 0 to 39.5 mol%, and the dicarboxylic acid containing a radical polymerizable double bond is 0.5 to 10 mol%.

When the content of the aromatic dicarboxylic acid is less than 60 mol%, or the content of the aliphatic dicarboxylic acid and/or the alicyclic dicarboxylic acid exceeds 39.5 mol%, the heat resistance may be lowered. The situation. Further, when the content of the dicarboxylic acid containing a radical polymerizable double bond is less than 0.5 mol%, the grafting of the radical polymerizable monomer to the hydrophobic copolymerized polyester is not easily performed efficiently. Chemical. On the other hand, when the content of the dicarboxylic acid containing a radical polymerizable double bond exceeds 10 mol%, the viscosity may be excessively increased in the subsequent stage of the graft reaction to hinder the uniform reaction. .

More preferably, the content of the aromatic dicarboxylic acid is 63 to 98 mol%, and the content of the aliphatic dicarboxylic acid and/or the alicyclic dicarboxylic acid is 0 to 30 mol%, and the radical polymerizable property is contained. The content of the dicarboxylic acid of the double bond is 2 to 7 mol%.

The diol component constituting the "hydrophobic copolymerized polyester" is composed of an aliphatic diol having 2 to 10 carbon atoms and/or an alicyclic diol having 6 to 12 carbon atoms and/or a diol having an ether bond. Composition.

"Aromatic diol having a carbon number of 2 to 10" includes ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and neopentane Glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-ethyl-2-butylpropanediol, and the like.

The "alicyclic diol having a carbon number of 6 to 12" includes 1,4-cyclohexanedimethanol or the like.

The "diol containing an ether bond" includes, in addition to diethylene glycol, triethylene glycol, and dipropylene glycol, two phenolic hydroxyl groups in the bisphenol, and the addition of ethylene oxide or propylene oxide. Alcohols such as 2,2-bis(4-hydroxyethoxyphenyl)propane and the like. Polyethylene glycol, polypropylene glycol, and polytetramethylene glycol can also be used as needed.

The "hydrophobic copolymerized polyester" used in the present invention may copolymerize 0 to 5 mol% of a trifunctional or higher polycarboxylic acid and/or a polyhydric alcohol. "Trifunctional or higher polycarboxylic acids" include: trimellitic acid (anhydride), pyromellitic acid (anhydride), benzophenone tetracarboxylic acid (anhydride), trimesic acid, ethylene glycol double (dehydration partial) Benzoic acid ester), glycerol ginseng (dehydrated trimellitate), and the like. Further, the "trifunctional or higher polyhydric alcohol" includes glycerin, trimethylolethane, trimethylolpropane, and neopentylol.

The trifunctional or higher polycarboxylic acid and/or polyol is copolymerized in an amount of from 0 to 5 mol%, preferably from 0 to 3 mol%, based on the total acid component or all of the diol component. When it exceeds 5 mol%, gelation will occur easily at the time of polymerization.

The "hydrophobic copolymerized polyester" used in the present invention preferably has a weight average molecular weight of from 5,000 to 50,000. When the weight average molecular weight is less than 5,000, the heat resistance is lowered, and when it exceeds 50,000, problems such as gelation occur during polymerization.

(Grafting of a radically polymerizable monomer of a hydrophobic copolymerized polyester)

In the present invention, the graft polymerization of the radical polymerizable monomer of the "hydrophobic copolymerized polyester" is carried out by dissolving the hydrophobic copolymerized polyester in an organic solvent, and a graft polymerization initiator is used. It is carried out by reacting with at least one radical polymerizable monomer.

Further, the reaction product after completion of the graft reaction is a hydrophobic copolymer which is not subjected to grafting, in addition to the graft copolymer of the hydrophobic copolymerized polyester and the radical polymerizable monomer. A (co)polymer obtained from a polyester and a radically polymerizable monomer which is not grafted to the hydrophobic copolymerized polyester. In the present specification, the "polyester-based graft copolymer" is not only a polyester-based graft copolymer as described above but also a hydrophobic copolymerized polyester which is not subjected to grafting. (co)polymer and monomer (residual monomer) reaction mixture obtained from the ungrafted radical polymerizable monomer.

The mass ratio of the "hydrophobic copolymerized polyester" to the "radical polymerizable monomer" which is suitable for the purpose of the present invention is preferably in the range of polyester/radical polymerizable monomer = 40/60 to 95/5. More preferably, it is in the range of 55/45 to 93/7, and most preferably in the range of 60/40 to 90/10. When the mass ratio of the hydrophobic copolymerized polyester is less than 40% by mass, the superior heat resistance of the polyester resin cannot be exhibited. On the other hand, when the mass ratio of the hydrophobic copolymerized polyester is more than 95% by mass, the adhesion of the polyester resin is likely to occur.

The graft polymerization initiator which can be used in the present invention includes, for example, an organic peroxide or an organic azo compound which is well known to those skilled in the art, and an "organic peroxide" system including: benzamidine peroxidation. And peroxy trimethylacetate tert-butyl ester. "Organic azo compounds" include: 2,2'-azobisisobutyronitrile, 2,2'-azobis(2,4-dimethylvaleronitrile), azobisdimethylvaleronitrile, etc. . The amount of the polymerization initiator to be used for the graft polymerization is at least 0.2% by mass or more, preferably 0.5% by mass or more based on the radical polymerizable monomer.

In the present invention, in addition to the graft polymerization initiator, a "chain transfer agent" for adjusting the chain length of the branched polymer may be used as needed, for example, octyl mercaptan, thiol ethanol, 3-three. Grade butyl-4-hydroxyanisole and the like. In this case, the chain transfer agent is preferably added in the range of 0 to 5% by mass based on the radical polymerizable monomer.

The reaction solvent used in the grafting of the radical polymerizable monomer of the hydrophobic copolymerized polyester is preferably composed of an aqueous organic solvent having a boiling point of 50 to 250 °C. The term "aqueous organic solvent" as used herein means an organic solvent having a solubility in water at 20 ° C of at least 10 g/L or more, preferably 20 g/L or more. The aqueous organic solvent having a boiling point of more than 250 ° C is too slow in evaporation rate, and the solvent cannot be sufficiently removed even if a high temperature baking of the coating film is taken, and thus it is not appropriate. Further, in the case of an aqueous organic solvent having a boiling point of 50 ° C or lower, if a grafting reaction is to be carried out in such a solvent, the graft polymerization initiator which is cleaved into a radical at a temperature of not higher than 50 ° C may not be used. This leads to an increased risk of use and is therefore not good.

Among the aqueous organic solvents used in the present invention, it is good at dissolving a hydrophobic copolymerized polyester, and is relatively good at dissolving a radical polymerizable monomer containing a carboxyl group-containing radical polymerizable monomer, and a radical polymerizable monomer. The "first group of aqueous organic solvent" of the graft reaction product (polyester-based graft copolymer) includes, for example, "esters" such as ethyl acetate; methyl ethyl ketone, methyl isobutyl ketone "ketones" such as cyclohexanone; "cyclic ethers" such as tetrahydrofuran, dioxane, and 1,3-dioxane; ethylene glycol dimethyl ether, propylene glycol methyl ether, and propylene glycol propyl "Glycol ethers" such as ether, ethylene glycol ethyl ether, ethylene glycol butyl ether, etc.; "carbitol" such as methyl carbitol, ethyl carbitol, butyl carbitol, etc. ; glycols; lower esters of glycol ethers such as ethylene glycol diacetate, ethylene glycol ethyl ether acetate; "keto alcohols" such as diacetone alcohol; dimethylformamide "N-substituted decylamines" such as dimethylacetamide and N-methylpyrrolidone.

Further, the hydrophobic copolymerized polyester is hardly dissolved, but it is preferable to dissolve the radically polymerizable monomer containing a carboxyl group-containing radical polymerizable monomer and the graft reaction product of the radical polymerizable monomer. The second group of aqueous organic solvents include water, lower alcohols, lower carboxylic acids, lower amines, and the like. A second group of aqueous organic solvents which are particularly preferred in the practice of the present invention are alcohols and glycols having 1 to 4 carbon atoms.

The mode of carrying out the grafting reaction in a single solvent includes, for example, a mode in which only one of the first group of aqueous organic solvents is selected. The mode of performing the mixed solvent includes, for example, selecting only a plurality of modes from the first group of aqueous organic solvents, or selecting at least one of the first group of aqueous organic solvents, and adding it to at least the second group of aqueous organic solvents. A mode of one.

Grafting can be carried out in any of the cases where the reaction solvent is a single solvent from the first group of aqueous organic solvents and the mixed solvent composed of each of the first group and the second group of aqueous organic solvents. Polymerization. However, differences in the characteristics of the grafting reaction, the graft reaction product, and the appearance and properties of the aqueous dispersion derived therefrom can be observed. The graft reaction of the present invention is preferably a mixed solvent comprising one of the first group and the second group of aqueous organic solvents. The reason for this is also to adjust the dissolution state of the hydrophobic copolymerized polyester so that it is less likely to cause intermolecular crosslinking, which is effective in preventing gelation in the graft reaction, and high-efficiency grafting and inhibition. The coexistence of both of the gelation in the latter mixed solvent system can be achieved. It is confirmed that the hydrophobic copolymerized polyester molecular chain in the solvent of the first group exhibits an extended (stretched) state by measuring the viscosity of the hydrophobic copolymerized polyester in the solutions, and is in the first The hydrophobic copolymerized polyester molecular chain in the mixed solvent of the group/second group is in a state of being entangled in a spheroidal shape (small stretch).

In the present invention, the mass ratio of the first group/second group mixed solvent is more preferably from 95/5 to 10/90, still more preferably from 90/10 to 20/80, most preferably at 85/. Range of 15 to 30/70. The optimum mass ratio is determined depending on the solubility of the hydrophobic copolymerized polyester to be used and the like.

(Polyester graft copolymer)

The polyester-based graft copolymer obtained by grafting as described above is in the form of a solution or dispersion of an organic solvent or a solution or dispersion of an aqueous solvent. In particular, in the form of a dispersion of an aqueous solvent, that is, a dispersion of water, it is preferred from the viewpoint of work environment and coatability. In the aqueous dispersion system, a radically polymerizable monomer containing a hydrophilic radical polymerizable monomer is graft-polymerized to a hydrophobic copolymerized polyester in the aqueous organic solvent, and then added to water, followed by distillation of water. Made with organic solvents.

In the present invention, the acid value of the polyester-based graft copolymer is preferably 600 equivalents/10 ⁶ g or more. A more preferred acid value is 1,200 equivalents/10 ⁶ grams or more. If the acid value of the polyester-based graft copolymer is less than 600 equivalents/10 ⁶ g, the adhesion to the layer coated on the main primer treatment material cannot be said to be sufficient.

The glass transition temperature of the polyester-based graft copolymer is not particularly limited, but is preferably 30 ° C or lower. By using a polyester-based graft copolymer having a glass transition temperature of 30 ° C or less for use in an anti-blocking modified layer, heat-shrinkable polyid having particularly excellent thermal blocking resistance can be obtained. Ester film.

The aqueous dispersion of the present invention has an average particle diameter of 500 nm or less as measured by a laser light scattering method, and has a translucent or milky white appearance. Although the aqueous dispersion of various particle diameters can be obtained by adjusting the polymerization method, the particle diameter is suitably from 10 to 500 nm, and from the viewpoint of dispersion stability, it is preferably 400 nm or less, more preferably 300 nm or less. When the particle diameter exceeds 500 nm, the gloss of the surface of the film may be lowered and the transparency of the coating may be lowered. Further, when it is less than 10 nm, there is a possibility that the heat-resistant adhesiveness of the object of the present invention is lowered.

The polyester-based graft copolymer which is suitably used in the present invention is preferably neutralized with a basic compound, and can be easily water-dispersed by being neutralized. The basic compound is preferably a compound which will volatilize when forming a coating film or when baking curing by a hardening agent, and is preferably, for example, ammonia, an organic amine or the like. Preferred examples include: triethylamine, N,N-diethylethanolamine, N,N-dimethylethanolamine, aminoethanolamine, N-methyl-N,N-diethanolamine, isopropylamine , iminodipropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, secondary-butylamine, propylamine, methylamine Alkylamine, dimethylaminopropylamine, methylimidopropylamine, 3-methoxypropylamine, monoethanolamine, diethanolamine, triethanolamine, and the like.

The basic compound preferably has a pH of from 5.0 to 9.0 in accordance with the content of the carboxyl group contained in the polyester-based graft copolymer, using at least partial neutralization or complete neutralization. When a basic compound having a boiling point of 100 ° C or less is used, since it is easy to reduce the residual basic compound in the coating film after drying, it has excellent coating film stability. Further, by using a basic compound of 100 ° C or higher or controlling drying conditions, the alkali compound is allowed to remain in the coating film after drying at 500 ppm or more, whereby the transferability of the printing ink can be improved.

In the polyester-based graft copolymer used in the present invention, the polymer (graft chain portion) of the radical polymerizable monomer preferably has a weight average molecular weight of 500 to 50,000. When the weight average molecular weight of the polymer of the radically polymerizable monomer is controlled to be less than 500, it is usually difficult, and the grafting efficiency is lowered, so that the hydrophilic base cannot be sufficiently imparted to the hydrophilic copolymerized polyester. . Further, the graft polymer of the radical polymerizable monomer is a hydrated layer in which dispersed particles are formed, but in order to impart a sufficient hydration layer and a stable aqueous dispersion, graft polymerization of a radical polymerizable monomer is obtained. The weight average molecular weight of the substance is preferably 500 or more. Further, the upper limit of the weight average molecular weight of the graft polymer of the radical polymerizable monomer is preferably 50,000 from the viewpoint of polymerizability at the time of solution polymerization. The control of the weight average molecular weight within this range can be carried out by the amount of the initiator, the monomer dropping time, the polymerization time, the reaction solvent, the monomer composition, or a combination of a chain transfer agent or a polymerization inhibitor as appropriate.

(anti-adhesive improvement layer)

The anti-blocking modified layer of the present invention may be formed only of the polyester-based graft copolymer as described above, but may be used in combination with other purposes for mixing a general-purpose polyester resin or polyurethane. Various functionalities such as a resin, an acrylic resin, such a copolymer, various water-soluble resins, or a conductive resin such as polyaniline or polypyrrole, an antimicrobial resin, an ultraviolet absorbing resin, or a gas barrier resin. Resin is formed.

In addition, in the anti-blocking modified layer, various additives such as a surfactant, an antistatic agent, an inorganic lubricant, an organic lubricant, an antibacterial agent, and a photo-oxidation touch can be mixed without impairing the efficacy of the present invention. Medium, UV absorber, etc.

In the present invention, an anti-blocking improvement of a polyester-based graft copolymer obtained by grafting at least one radical polymerizable monomer to a hydrophobic copolymerized polyester on at least one side of a film The mode of the layer is also preferred. In this mode, an anionic antistatic agent is contained in a solution or dispersion for forming the anti-blocking modified layer or a solution or dispersion of an aqueous solvent, whereby both components can be imparted on the surface of the film.

Next, a method of producing a film relating to the present invention will be described.

By producing an unstretched polyester film containing a mixture of one or two or more kinds of polyesters, and stretching them, and heat-treating, the heat shrinkage characteristics and solvent adhesion as described above can be obtained. A film related to the present invention.

The polyester used for producing the unstretched polyester film is selected from the group consisting of an aromatic dicarboxylic acid, an aromatic dicarboxylic acid ester, an aliphatic dicarboxylic acid, an oxycarboxylic acid, and a trivalent or higher carboxylic acid. One or two or more kinds of monomers and one or more monomers selected from the group consisting of polyols, such as a transesterification reaction catalyst such as zinc acetate, and/or a polymerization catalyst such as antimony trioxide The polymerization is carried out underneath, whereby it can be obtained.

When a polyester to which a lubricant or the like is added is obtained, a method of dispersing a lubricant or the like in the polymerization system in the polymerization step of the monomer may be used; the polyester obtained by the polymerization is again melted, and A method of adding a lubricant or the like to the molten polyester or the like.

The polymerized polyester was taken out from the polymerization apparatus in a molten state in a molten state, and immediately cooled with water, and then cut by a strand cutter to prepare pelletized. The cut pellets after the cutting have a cylindrical shape with an elliptical bottom surface.

In the case of producing a film containing two or more kinds of polyesters having different compositions, it is necessary to mix two or more kinds of polyester pellets having different compositions. In this case, if the polyester pellets having the highest use ratio are used, the pellets and the pellets are used. When the long diameter, the short diameter, and the cylindrical height of the elliptical bottom surface are polyester dicing in the range of ±20% or less (preferably within ±15%) of the average size of each of the bottom surfaces, the granule can be suppressed in the hopper. The unevenness of the same type of polyester pellets is uneven, so that uniform dispersion of the lubricant or the like in the film can be achieved.

Further, in the case of mixing the pellet of the copolymerized polyester and the pelletizing of the homopolyester, since the copolymerized polyester having a generally low melting point has a problem of difficulty in use in drying, etc., it is preferred to homopolymerize The ester (polyethylene terephthalate, polyethylene naphthalate, 1,4-cyclohexene diethylene glycol terephthalate, etc.) is mixed with the copolymerized polyester.

The method for producing an unstretched film from polyester pellets includes: (1) drying the pellets in advance using a dryer such as a hopper dryer, a paddle dryer, or a vacuum dryer, and then at 200 to 300 ° C The method of extruding into a film and cooling it at a temperature; (2) removing the undried polyester granules in the vented extruder, removing water from one side, extruding into a film and cooling Method and so on. In the case of extrusion, any of the well-known methods such as the T-die method and the tubular method can be used. The cooling after extrusion is quenched, for example, by a chill roll having a surface temperature of 25 °C.

Since the heat shrinkable label having the main shrinkage direction in the transverse direction is practical, the extension processing of the unstretched film suitable for the production of the label is taken as an example (hereinafter, "main shrinkage direction" after the next paragraph" It is synonymous with "transverse direction", and "orthogonal direction" is synonymous with "lengthwise direction".). Further, in the case of manufacturing a heat-shrinkable label having a main shrinkage direction in the longitudinal direction, the direction of extension in the following unstretched film processing may be changed to 90 degrees.

If it is necessary to homogenize the thickness distribution of the heat-shrinkable polyester film, it is preferred to preheat the film at a low wind speed of 0.0013 cal/cm ² ‧ sec ‧ ° C or less before stretching. The film is allowed to reach a film temperature of Tg-20 ° C to Tg + 60 ° C. The temperature at each position of the surface of the film under the preheating step is preferably within ± the distance from the longitudinal direction of the winding length of the film of the film of the present invention. Within 1 ° C, and more preferably within ± 0.5 ° C of the average temperature.

The extension can be carried out using a tenter, and the temperature of the Tg-30 ° C to Tg + 40 ° C, more preferably at a temperature of Tg - 15 ° C to Tg + 30 ° C, the transverse direction of the film is extended to 2.3. It is 7.3 times, preferably 3.5 to 6.0 times. When the hot air of 60 to 120 ° C is blown to the stretched film, the stretched polyester can be fixed, so that the main shrinkage of the heat-shrinkable film can be lowered. In addition, if the hot air of 30 to 60 ° C is continuously blown to the stretched film while the hot air is blown in front, the heat shrinkage in the main shrinkage direction from the [(the heat shrinkage rate in the main shrinkage direction is more than 0% + 10 ° C)) The value obtained by subtracting [the heat shrinkage rate in the main shrinkage direction of the heat shrinkage rate in the main shrinkage direction of more than 0% - 5 ° C) is less than 20%.

Further, since the fluctuation of the temperature condition at the time of stretching is likely to affect the shrinkage characteristics of the heat-shrinkable film, it is preferable to suppress the temperature at the time of stretching and the variation of the temperature of the hot air after the stretching. The temperature at each position of the surface of the film in the stretching step is preferably within ±1 ° C of the average temperature of the film surface in the range of the distance from the longitudinal direction of the winding length of the film of the film relating to the present invention. More preferably, it is within ±0.5 ° C of the average temperature. In addition, from the viewpoint of suppressing heat generation inside the film accompanying stretching and reducing problems such as film temperature spots in the lateral direction, it is preferable that the heat transfer coefficient in the extending step is 0.0037 J/cm ² ‧ sec ‧ ° C or more Good is 0.00544 to 0.00837 J/cm ² ‧ sec ‧ ° C.

Although it is not always necessary to carry out the longitudinal extension which causes the contraction in the longitudinal direction, from the viewpoint of improving the strength of the film, the tenter may be applied as long as it does not impair the characteristics of the film relating to the present invention. Longitudinal extension of the machine. The extension mode in which the biaxial extension of the longitudinal and transverse directions is applied may be either a sequential biaxial extension and a simultaneous biaxial extension, and may be applied as needed. Further, the order of extension in the case of successive biaxial stretching may be any one of vertical and horizontal, horizontal and vertical, vertical and horizontal, horizontal and vertical. Even in the case of such a longitudinal stretching step or a biaxial stretching step, the film surface temperature of the preheating step, the film surface temperature of the stretching step, and the heat transfer coefficient of the stretching step are still transversely extended as described above. The same.

The heat-shrinkable polyester film can be produced by the above-described process. However, if a heat-shrinkable polyester film having a preferred mode in which an anionic antistatic agent is present on at least one side is to be produced, an anion will be contained. The liquid of the antistatic agent is applied to at least one side of the film. After the solution is applied, it is uniaxially stretched or biaxially stretched. That is, (1) uniaxially or biaxially extending after applying the antistatic agent-containing solution to the unstretched film; or (2) if the unstretched film is uniaxially stretched or biaxially extended In the first extension step and the second extension step of manufacturing the polyester-based extension film and the second extension step of further extending the polyester-based extension film uniaxially or biaxially. The film between the stretching steps is coated with an antistatic agent solution. Since it is not a method of incorporating an antistatic agent into a film, the antistatic agent can be directly deposited on the surface of the film by using the coating method as described above, and therefore, it is not necessary to rely on the glass transition temperature of the polyester constituting the film. The high level of the film can effectively exert an antistatic effect, and can also prevent deterioration or coloration of the film caused by the antistatic agent. The elongation conditions are not significantly different from those of the uncoated anionic antistatic agent as described above.

The solvent containing the antistatic agent liquid applied to the surface of the film is preferably a mixed solvent of a lower alcohol having a carbon number of 1 to 3 and water, although it is not particularly limited. Preferred are lower alcohols having a carbon number of 1 to 3 which may be mixed with water in any ratio, and include, for example, methanol, ethanol, n-propanol, isopropanol. It is not preferable because an alcohol having a large carbon number is easily separated from water to cause a coating spot, but if the degree of phase separation does not occur, the number of carbons and the number of carbons may be 1 Use the lower alcohols of 3 to use.

The amount of the lower alcohol as described above in the antistatic agent-containing liquid is preferably set to 10% by mass or more. When the amount of the lower alcohol is less than 10% by mass, the surface tension of the antistatic agent-containing liquid will increase so that the wettability of the film is lowered to easily cause coating spots, and the reason is not clear, if it is coated. When a sudden change in temperature and humidity occurs during the subsequent drying, the transparency of the film may be lowered to impair the practicality. On the other hand, the upper limit amount of the lower alcohol in the antistatic agent-containing liquid is preferably 60% by mass. If it exceeds 60% by mass, explosion-proof measures must be taken to avoid the risk of explosion of lower alcohol. Further, in the case where an alcohol having a higher carbon number is used in combination with the lower alcohol, it is recommended to set the total alcohol amount to 60% by mass or less.

Further, in the production method in which the anti-blocking improving layer is provided on at least one side of the film, a coating method in which a coating liquid containing a polyester-based graft copolymer is applied onto the polyester-based base film is preferred as a preferred mode. In addition, there is a laminate method in which a resin layer containing a polyester-based graft copolymer is laminated, but in the present invention, it is preferably formed by a coating method. The reason for this is that the laminate method has a lower limit of the thickness of the anti-blocking modified layer, and may also cause a defect in characteristics of the film as a substrate. On the other hand, in the coating method, the polyester-based graft copolymer can be present on the surface of the film in a thin film state, so that the blocking resistance can be imparted without changing the characteristics of the film as the substrate.

Coating of Coating Liquid

As the coating liquid containing the polyester-based graft copolymer, an organic solvent solution or an organic solvent dispersion of a polyester-based graft copolymer, or an aqueous solvent solution or an aqueous solvent dispersion can be used. In particular, an aqueous solvent solution or an aqueous solvent dispersion is preferred because it does not use an organic solvent which causes problems in the environment.

Specifically, the solvent is preferably a mixed solvent of a lower alcohol having a carbon number of 1 to 3 and water. The lower alcohol having a carbon number of 1 to 3 is suitably mixed with water at any ratio such as methanol, ethanol, n-propanol or isopropanol. The alcohol having a large carbon number is phase-separated from water when the coating liquid is prepared, so that when such a coating liquid is used, coating spots are likely to occur, which is not preferable. However, if the degree of phase separation does not occur, it may be used in combination with a lower alcohol having a carbon number of 1 to 3.

The amount of the lower alcohol in the coating liquid is preferably 10% by mass or more. When the amount of the lower alcohol is less than 10% by mass, the surface tension of the coating liquid is increased to lower the wettability to the film, so that the coating spot is likely to occur. Further, although the reason is not clear, when the heat-shrinkable film obtained by drying the coating liquid is subjected to a sudden change in temperature and humidity, the transparency of the film may be lowered to impair the practicality. .

Further, the amount of the lower alcohol in the coating liquid is preferably 60% by mass or less. When the amount of the lower alcohol is more than 60% by mass, the amount of the organic solvent in the coating liquid is increased, so that when the coating liquid is applied during the film production process, the risk of explosion is caused, and therefore, explosion-proof measures must be taken. Further, in the case where an alcohol having a larger carbon number is used in combination with the lower alcohol, it is recommended to set the total amount of the alcohol in the coating liquid to 60% by mass or less.

The content of the solid content of the polyester-based graft copolymer and the crosslinking bond agent (described later in the solvent) in the organic solvent or the aqueous solvent is preferably 0.5% by mass or more (more preferably 1% by mass or more) and 50% by mass. The following (more preferably 30% by mass or less). Further, an inorganic lubricant may be mixed in the coating liquid.

The method of applying the coating liquid containing the polyester-based graft copolymer to the polyester-based base film is not particularly limited, and an air knife method, a gravure rotation method, a reverse method, a mold method, a rod method, or the like can be used. A conventional coating method such as a dipping method.

The coating amount of the coating liquid, a polyester graft copolymer solid component basis, is preferably from 0.002 to 0.5g / m ^2, more preferably 0.004 to 0.05g / m ^2. When the coating amount is less than 0.002 g/m ² , there is a possibility that the heat-resistant adhesive effect cannot be sufficiently ensured. Further, when the coating amount is more than 0.5 g/m ² , there is a possibility that the transparency or gloss of the film is lowered.

"dry"

The polyester-based graft copolymer used in the present invention has self-crosslinking property, and although it is not crosslinked at normal temperature, hydrogen removal due to thermal radicals is performed by heat during drying (hydrogen drawing An intermolecular reaction such as a reaction, and crosslinking is carried out without a crosslinking agent. By this, the anti-blocking property of the object of the invention can be revealed.

Although the drying conditions after coating are not particularly limited, in order to exhibit the self-crosslinking property of the polyester-based graft copolymer, it is preferred that the polyester-based base film and the polyester are not connected. The branch copolymer has a condition of increasing heat within a range of thermal deterioration. Specifically, it is preferably from 60 ° C to 250 ° C, still more preferably from 65 ° C to 220 ° C. However, by prolonging the drying time, sufficient self-crosslinking property can be exhibited at a relatively low temperature, and therefore, it is not necessarily the conditions as described above.

Regarding the crosslinkability of the coating film, although it can be evaluated by various methods, it includes, for example, measuring an insoluble component in a chloroform solvent which dissolves both the hydrophobic copolymerized polyester and the polyester-based graft copolymer. The method of rate, etc. The insoluble component ratio of the coating film obtained by drying at 80 ° C or lower and heat treatment at 120 ° C for 5 minutes is preferably 50% or more, more preferably 70% or more. If the insoluble component ratio of the coating film is less than 50%, not only the water resistance is insufficient, but also adhesion occurs.

In the present invention, by further adding a crosslinking bond to the coating liquid, it is possible to impart high water resistance and solvent resistance. The crosslinking bonding agent is a crosslinking structure which can be thermally or lightly reacted with a functional group or the like which is present in the polyester-based graft copolymer as described above, and finally forms a three-dimensional mesh structure. There is no particular restriction on the crosslinking of the bonding agent.

The "crosslinking bonding agent" includes a phenol formaldehyde resin which alkylates a condensate such as phenol or cresol with formaldehyde, and an adduct of formaldehyde, such as urea, melamine or benzoguanamine, and the addition thereof. An amine-based resin such as an alkyl ether compound composed of an alcohol having 1 to 6 carbon atoms; a polyfunctional epoxy compound; a polyfunctional isocyanate compound; a blocked isocyanate compound; and a polyfunctional oxime a compound; an oxazoline compound or the like.

"Phenol formaldehyde resin" includes, for example, alkylated (methyl, ethyl, propyl, isopropyl or butyl) phenol, p-tert-amyl phenol, 4,4'-di-butylene phenol , p-tertiary-butylphenol, o-, m-, p-cresol, p-cyclohexylphenol, 4,4'-isopropylidenephenol, p-nonylphenol, p-octylphenol, 3-fifteen a condensate of phenols such as alkylphenol, phenol, phenyl o-cresol, p-phenylphenol or xylenol with formaldehyde.

"Amine-based resin" includes, for example, methoxylated methylol urea, methoxylated methylol N, N-extended ethyl urea, methoxylated methylol dicyanamide, methoxy The group consists of methylol melamine, methoxylated methylol benzoguanamine, butoxylated methylol melamine, butoxylated hydroxymethylbenzoguanamine and the like. Preferred are methoxylated methylol melamine, butoxylated methylol melamine, and methylolated benzoguanamine.

"Polyfunctional epoxy compound" includes, for example, bisphenol A diglycidyl ether and oligomer thereof, hydrogenated bisphenol A diglycidyl ether and oligomer thereof, phthalic acid Diglycidyl ester, diglycidyl isophthalate, diglycidyl terephthalate, diglycidyl p-oxybenzoate, diglycidyl tetrahydrophthalate, hexahydroortylene Diglycidyl formate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butyl Glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether and polyalkylene glycol diglycidyl ether, trimellitic acid triglycidyl ester, isomeric cyanuric acid Glycidyl ester, 1,4-diglycidyloxybenzene, diglycidylpropyl propyl urea, glycerol triglycidyl ether, trimethylolpropane triglycidyl ether, neopentyl alcohol trihydrate A glyceryl ether, a triglycidyl ether of a glycerol alkylene oxide adduct, or the like.

The "polyfunctional isocyanate compound" includes a low molecular or high molecular aromatic, an aliphatic diisocyanate, or a trivalent or higher polyisocyanate. "Polyisocyanate" includes: tetramethylene diisocyanate, hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, decyl diisocyanate, hydrogenated deuterated diisocyanate , isophorone diisocyanate, and terpolymers of such isocyanate compounds. And a low molecular weight hydrogenated compound such as ethylene glycol, propylene glycol, trimethylolpropane, glycerin, sorbitol, ethylidene diamine, monoethanolamine, diethanolamine, triethanolamine or the like in excess of the isocyanate compound. A compound containing a terminal isocyanate group obtained by a reaction of a "polymer active hydrogenated compound" such as a polyester polyol, a polyether polyol or a polydecylamine.

The "blocked isocyanate compound" is prepared by subjecting an isocyanate compound and a blocking agent as described above to an addition reaction by a conventionally known appropriate method. The "isocyanate blocking agent" includes, for example, "phenols" such as phenol, cresol, xylenol, resorcin, nitrophenol, and chlorophenol; and sulfur in thiophenol and methylthiophenol. "Phenols"; "indoles" such as acetone oxime, methyl ethyl ketone oxime, cyclohexanone oxime, etc.; "alcohols" such as methanol, ethanol, propanol and butanol; chlorohydrin, 1,3-dichloro "Alcohol-substituted alcohols" such as 2-propanol; "third-order alcohols" such as tertiary-butanol and tertiary-pentanol; ε-caprolactam, δ-valeroinamide "Intrinsic amines" such as ν-butyrolactam and β-propyl decylamine; aromatic amines; quinone imines; acetoacetone, acetamidine acetate, ethyl malonate, etc. "Active methylene compounds"; mercaptans; imines; ureas; diaryl compounds; sodium hydrogen sulfite.

The cross-linking bonding agents as described above may each be used singly or in combination of two or more. The compounding amount of the crosslinking agent is preferably from 1 part by mass to 40 parts by mass based on 100 parts by mass of the polyester-based graft copolymer. The method for mixing the crosslinking agent includes: (1) if the crosslinking agent is water-soluble, directly dissolving or dispersing it in an aqueous solvent solution or an aqueous solvent dispersion of the graft copolymer; or (2) When the crosslinking agent is oil-soluble, a method of adding the reaction liquid after completion of the grafting reaction is carried out. These methods can be appropriately selected depending on the kind and nature of the crosslinking agent. Also, the cross-linking bonding agent may be used in combination with a hardener or an accelerator.

Extension, and heat fixation

In the present invention, it is preferred to further uniaxially extend at least further after performing the drying as described above, followed by heat setting. The extension is applied, whereby the film can be easily formed. Further, by heat-fixing, the polyester is aligned so that the main shrinkage ratio of the heat-shrinkable film obtained by using it is lowered. The elongation conditions are not much different from those in the case where the anti-blocking improved layer mode is not provided as described above.

If the extended film is blown with hot air of 60 to 120 ° C, the extended polyester alignment can be fixed, and the main shrinkage of the heat-shrinkable film is lowered. Further, it is preferred that the hot film of 30 to 60 ° C is continuously blown to the stretched film immediately following the hot air blowing. Thereby, the heat shrinkage rate in the main shrinkage direction of [(the heat shrinkage rate in the main shrinkage direction is more than 0% + 10 ° C)] can be obtained by subtracting [(the heat shrinkage rate in the main shrinkage direction is more than 0%) The heat shrinkage rate in the main shrinkage direction of the temperature - 5 ° C) is a heat-shrinkable polyester film obtained by a value of less than 20%.

When a mode in which an anionic antistatic agent is contained in the anti-adhesion improving layer is obtained, the anionic antistatic agent may be contained in a coating liquid for forming the anti-blocking improving layer, and then coated. It can be dried, so efficient processing can be achieved.

(heat shrinkable label)

The heat-shrinkable label of the present invention is produced by using the heat-shrinkable polyester film as described above. At this time, printing processing can also be applied as needed.

"Embodiment"

Hereinafter, the present invention will be described in more detail by way of examples, but the invention is not limited by the examples. First, the evaluation methods of the films obtained in the examples and comparative examples will be explained. In addition, unless otherwise indicated, in the embodiment, the word "part" means "mass portion", and the item labeled "%" means "mass%".

(1) Analysis of NMR (nuclear magnetic resonance) of polyester

Each sample was dissolved in a solvent obtained by mixing chloroform D (manufactured by EURISO-TOP Co., Ltd.) and trifluoroacetic acid D1 (manufactured by EURISO-TOP Co., Ltd.) at a ratio of 10:1 (volume ratio) to prepare a sample solution, and then using NMR ( "GEMINI-200"; manufactured by Varian Co., Ltd.) The ¹ H-NMR of the sample solution was measured under the measurement conditions of a temperature of 23 ° C and an integrated count of 64 times. The peak intensity of a specific proton was calculated in the NMR measurement, and the pellet composition and film composition were calculated and expressed in terms of mol%.

(2) Thermal shrinkage rate

The film was cut into a square of 10 cm × 10 cm, and treated in a hot water at a specific temperature of ±0.5 ° C (refer to Table 2 for a predetermined temperature) under no load for 10 seconds to be heat-shrinked, and immediately immersed at 25 ° C. After 10 seconds in water at ±0.5 ° C, the longitudinal and transverse directions of the sample were measured, and then the heat shrinkage rate was calculated according to the following formula:

Heat shrinkage rate (%) = (length before shrinkage - length after shrinkage) 长度 length before shrinkage × 100

(3) Haze

The heat-shrinkable polyester film obtained after being stored for 4 weeks in an atmosphere having a temperature of 30 ° C and a relative humidity of 85% is solvent-bonded or heat-sealed to enable the main shrinkage direction of the film to be A tubular shape having a diameter of 11 cm and a length of 16 cm was formed in a uniform manner in the radial direction, and then a cylindrical glass bottle having a temperature of 40 ° C and a diameter of 6.6 cm was placed in the tubular film, and 150 ° C was blown toward the film ( The hot air at 10 meters/second lasted for 13 seconds. The film after shrinkage by hot air (the number of tubular film samples was 10) was cut out, and this was used as a film sample after heat shrinkage. Then, the haze of the film after heat shrinkage was measured in accordance with the guidelines of JIS K7136, and the average value was calculated. In addition, the average value of the haze was also calculated for the film before heat shrinkage.

(4) Solvent adhesion

Applying 1,3-dioxane to a single side of the heat-shrinkable film with a cotton swab along the longitudinal direction of the film and a coating amount of 5 ± 0.3 g/m ² and a coating width of 5 ± 1 mm, and then applying The coated portion is bonded to the uncoated longitudinal film surface to produce a tubular film. A tubular film having a length of 15 mm in the longitudinal direction including the bonding portion as described above was cut out from the tubular film after 24 hours at a temperature of 25 ° C, and mounted on a universal tensile testing machine (manufactured by BALDWIN Co., Ltd.). "STM-50") was peeled off by a 90° peel test at a tensile speed of 200 mm/min. The maximum strength of the peeling is regarded as the solvent peel strength.

(5) Shrinkage finishability

The ink of the grass green ‧ white ‧ white color of Toyo Ink Manufacturing Co., Ltd. was previously printed in three colors using a printing machine in a heat shrinkable film. Next, the heat-shrinkable label is produced by the solvent bonding method or the heat sealing method so that the transverse direction (diameter direction) can become the main shrinkage direction. The label was covered with a glass bottle at a temperature of 60 ° C, and a hot air of 175 ° C (wind speed of 12 m / sec) was blown for 10 seconds to cause heat shrinkage. The shrinkage and completion of the entire heat-shrinkable label were visually confirmed and evaluated on the following four levels. In addition, in the following evaluation criteria, "○" is a good level, and "△", "X", and "XX" are not good. In addition, in the following "accuracy" of the evaluation criteria, there are jumps, wrinkles, insufficient shrinkage, internal end of the label, and shrinkage whitening.

○: Good processing completion

△: slightly disadvantageous (within two places)

X: There are disadvantages (3 to 5)

XX: Many disadvantages (more than 6)

(6) Glass transition temperature (Tg)

A solution or dispersion of the polyester-based graft copolymer was applied to a glass plate, followed by drying at 170 ° C to obtain a graft polymer solid component. 10 mg of the solid component was taken in a sample tray, manufactured using a differential scanning calorimeter (Shimadzu Corporation), an atmospheric control device: FC-60A, workstation (TA-60WS), and 10 atmospheres under a nitrogen atmosphere. The glass transition temperature (Tg) was determined from the data measured at a heating rate of ° C/min.

(7) Anti-blocking

Using a heat sealer, after the surface temperature of the heat seal bar is in the range of 95 ± 0.5 ° C, and the pressure is 40 N / cm ² for 300 seconds, the film is heat-sealed to each other, and the width is 15 mm. The sample was measured for peel strength by a tensile tester and evaluated on the following basis:

○: Peel strength is less than 0.1 N/15 mm

X: Peel strength is 0.1N/15mm or more

(8) Surface inherent resistance

The surface specific resistance measuring device (main body: R8340, sample box: R12704) manufactured by ADVANTEST was used for measurement under an atmosphere of 100 V voltage and 23 ° C ‧65% RH, and the read value of the measuring device was used as the surface specific resistance. .

(Synthesis Example A: Synthesis of polyester)

Dimethyl terephthalate (DMT) as a dicarboxylic acid component and ethylene glycol (EG) as a polyol component are charged in a molar ratio of EG/DMT=2.2 with a stirrer, a thermometer, and Partial reflux cooler in stainless steel autoclave. When the EG is charged, the inorganic lubricant is dispersed in the ethylene glycol. Further, 0.05 mol% (relative to the dicarboxylic acid component) of zinc acetate as a transesterification catalyst, and 0.025 mol% (relative to the dicarboxylic acid component) were added as a polymerization in the autoclave. The tritium oxide of the condensing catalyst is subjected to a transesterification reaction while distilling the formed methanol out of the reaction system. Thereafter, the polycondensation reaction is carried out at 280 ° C and 26.7 Pa, and the polycondensation reaction is terminated under reduced pressure, and the obtained polymer is discharged into water in the form of strands under nitrogen pressure, and is in the form of strands. The cutter cuts the discharge to obtain a pellet of polyester A having a polyethylene terephthalate unit and containing 0.7% by mass of an inorganic lubricant. Its composition is shown in Table 1.

(Synthesis Examples B to D: Synthesis of Polyester)

Using DMT as the dicarboxylic acid component, using EG, EG and neopentyl glycol, 1,4-butanediol, or ethylene glycol and 1,4-cyclohexanedimethanol as the polyol component, and A. A pellet of polyesters B to D having the composition shown in Table 1 was obtained in the same manner (but without using an inorganic lubricant).

DMT: dimethyl terephthalate, EG: ethylene glycol, NPG: neopentyl glycol, CHDM: 1,4-cyclohexane dimethanol, BD: 1,4-butanediol

(Preferred Experimental Examples 1 to 5) [Experimental Example 1]

The pellets of polyesters A to C which were individually pre-dried were mixed at a ratio of A of 15% by weight, B of 75% by weight, and C of 10% by weight, and supplied to the extruder at 275 ° C. It was melt-extruded and quenched on a chill roll having a surface temperature of 25 ° C to obtain an unstretched film having a thickness of 180 μm. Next, the unstretched film was introduced into a tenter, and the preheating temperature of the unstretched film was set to 70 ° C, and then the unstretched film having a temperature of 72 ° C was extended 4.0 times in the lateral direction. Next, the stretched film was subjected to primary heat treatment at 95 ° C for 14 seconds, followed by a second heat treatment at 50 ° C for 10 seconds to obtain a heat-shrinkable polyester film having a thickness of 45 μm. The results of the evaluation of the properties of the film are shown in Table 2.

[Experimental Example 2]

The heat shrinkability of this experimental example was obtained in the same manner as in Experimental Example 1, except that the ratio of the pellets of the polyesters A to C was changed to A of 5% by weight, B of 80% by weight, and C of 15% by weight. Polyester film.

[Experimental Example 3]

In addition to using pellets of polyesters A, C, and D as pellets of polyester, and setting the ratio of such pellets to A of 15% by weight, C of 10% by weight, and D of 75% by weight, the rest The heat-shrinkable polyester film of this experimental example was obtained in the same manner as in Experimental Example 1.

[Experimental Example 4]

The ratio of the pellets of the polyesters A to C was changed to be 15% by weight of A, 75% by weight of B, and 10% by weight of C, and the film after stretching was subjected to primary heat treatment at 92 ° C for 14 seconds. The heat-shrinkable polyester film of this experimental example was obtained in the same manner as in Experimental Example 1.

[Experimental Example 5]

The ratio of the pellets of the polyesters A to C was changed to be 15% by weight of A, 75% by weight of B, and 10% by weight of C, and the film after stretching was subjected to primary heat treatment at 104 ° C for 14 seconds. The heat-shrinkable polyester film of this experimental example was obtained in the same manner as in Experimental Example 1.

(Experimental Examples 6 to 9 which are not good compared to Experimental Examples 1 to 5) [Experimental Example 6]

The heat-shrinkable polyester-based film of the present experimental example was obtained in the same manner as in Experimental Example 1, except that the initial heat treatment temperature after the extension in the transverse direction was changed to 85 °C.

[Experimental Example 7]

The heat shrinkability of the present experimental example was obtained in the same manner as in Experimental Example 1, except that the ratio of the pellets of the polyesters A to C was changed to 40% by weight of A, 50% by weight of B, and 10% by weight of C. Polyester film.

[Experimental Example 8]

The ratio of the pellets of the polyesters A to C was changed to 40% by weight of A, 50% by weight of B, and 10% by weight of C, and the initial heat treatment temperature after extending in the transverse direction was 85 ° C, and the rest was The heat-shrinkable polyester film of this experimental example was obtained in the same manner as in Experimental Example 1.

[Experimental Example 9]

This was obtained in the same manner as in Experimental Example 1 except that the pellets of the polyester B were 75 wt%, the pellets of C were 25% by weight, and the initial heat treatment temperature after the extension in the transverse direction was set to 85 °C. The heat-shrinkable polyester film of the experimental example.

(Specially good experimental examples 10 to 11) (Liquid 1 containing an anionic antistatic agent)

The dodecyl sulfonate was diluted with water, and isopropyl alcohol was added to obtain a liquid 1 containing an anionic antistatic agent having a solid concentration of 2% by mass (dodecyl sulfonate: 2% by mass, water: 63% by mass, isopropyl alcohol: 35 mass%).

(Liquid 2 containing an anionic antistatic agent)

Diluted with dodecylbenzenesulfonate in water, and isopropyl alcohol was added to obtain a liquid 2 containing an anionic antistatic agent having a solid concentration of 2% by mass (dodecylbenzenesulfonate: 2% by mass, Water: 63% by mass, isopropyl alcohol: 35% by mass).

[Experimental Example 10]

The pellets of polyesters A to C which were individually pre-dried were mixed at a ratio of A of 15% by weight, B of 75% by weight, and C of 10% by weight, and supplied to the extruder at 275 ° C. It was melt-extruded and quenched on a chill roll having a surface temperature of 25 ° C to obtain an unstretched film having a thickness of 180 μm. Applying the liquid 1 containing an anionic antistatic agent to one side of the unstretched film by air knife coating, and then introducing the unstretched film into the tenter, the preheating temperature of the unstretched film is set to 70 ° C, and The unstretched film having a temperature of 72 ° C was extended 4.0 times in the transverse direction. Next, the stretched film was subjected to primary heat treatment at 95 ° C for 14 seconds, followed by a second heat treatment at 50 ° C for 10 seconds to obtain a heat-shrinkable polyester film having a thickness of 45 μm. The results of the evaluation of the properties of the film are shown in Table 3.

[Experimental Example 11]

A heat-shrinkable polyester film was obtained in the same manner as in Experimental Example 10 except that the liquid 1 containing the anionic antistatic agent was changed to the liquid 2 containing the anionic antistatic agent.

(Experimental examples 12 to 20 which are not preferable to Experimental Examples 10 to 11) [Experimental Example 12]

A heat-shrinkable polyester film was obtained in the same manner as in Experimental Example 10 except that the application of the liquid 1 containing the anionic antistatic agent was not applied.

[Experimental Example 13]

The heat shrinkability of the present experimental example was obtained in the same manner as in Experimental Example 12 except that the ratio of the pellets of the polyesters A to C was changed to A of 5% by weight, B of 80% by weight, and C of 15% by weight. Polyester film.

[Experimental Example 14]

The pellets of polyesters A, C, and D were used as the pellets of the polyester, and the ratio of the pellets was set to A of 15% by weight, C of 10% by weight, and D of 75% by weight. Then, the heat-shrinkable polyester film of this experimental example was obtained in the same manner as in Experimental Example 12.

[Experimental Example 15]

The ratio of the pellets of the polyesters A to C was changed to be 15% by weight of A, 75% by weight of B, and 10% by weight of C, and the film after stretching was subjected to primary heat treatment at 92 ° C for 14 seconds. The heat-shrinkable polyester film of this experimental example was obtained in the same manner as in Experimental Example 12.

[Experimental Example 16]

The ratio of the pellets of the polyesters A to C was changed to be 15% by weight of A, 75% by weight of B, and 10% by weight of C, and the film after stretching was subjected to primary heat treatment at 104 ° C for 14 seconds. The heat-shrinkable polyester film of this experimental example was obtained in the same manner as in Experimental Example 12.

[Experimental Example 17]

The heat-shrinkable polyester-based film of the present experimental example was obtained in the same manner as in Experimental Example 12 except that the initial heat treatment temperature in the transverse direction was changed to 85 °C.

[Experimental Example 18]

The heat shrinkability of this experimental example was obtained in the same manner as in Experimental Example 12 except that the ratio of the pellets of the polyesters A to C was changed to 40% by weight of A, 50% by weight of B, and 10% by weight of C. Polyester film.

[Experimental Example 19]

The ratio of the pellets of the polyesters A to C was changed to 40% by weight of A, 50% by weight of B, and 10% by weight of C, and the initial heat treatment temperature after extending in the transverse direction was 85 ° C, and the rest was The heat-shrinkable polyester film of this experimental example was obtained in the same manner as in Experimental Example 12.

[Experimental Example 20]

The same procedure as in Experimental Example 12 was carried out except that the pellets of the polyester B were changed to 75 wt%, the pellets of C were 25% by weight, and the initial heat treatment temperature after the extension in the transverse direction was set to 85 °C. The heat-shrinkable polyester film of this experimental example.

(Specially good experimental examples 21 to 22) (Modulation of polyester base film)

The pellets of polyesters A to C which were individually pre-dried were mixed at a ratio of A of 15% by weight, B of 75% by weight, and C of 10% by weight, and supplied to the extruder at 275 ° C. It was melt-extruded and quenched on a chill roll having a surface temperature of 25 ° C to obtain an unstretched polyester-based base film having a thickness of 180 μm. The obtained film was subjected to NMR analysis to investigate the composition thereof. The results are shown in Table 4.

Heat shrinkage rate difference / 15 ° C: [(thermal shrinkage rate in the transverse direction is more than 0% temperature + 10 ° C), the heat shrinkage ratio in the transverse direction] - [(the transverse heat shrinkage rate exceeds 0% of the temperature - 5°C) thermal contraction rate in the transverse direction]

DMT: dimethyl terephthalate, EG: ethylene glycol, NPG: neopentyl glycol, BD: 1,4-butanediol

(Modulation of polyester-based graft copolymer)

<Preparation of Hydrophobic Copolymerized Polyester>

In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux cooler, 345 parts of dimethyl terephthalate (DMT) was added as a dicarboxylic acid component, and 211 parts of 1,4-butanediol. (BD), 270 parts of ethylene glycol (EG) as a diol component, and 0.5 part of tetra-n-butyl titanate as a polymerization catalyst, and then transesterification reaction from 160 ° C to 220 ° C for 4 hours . Next, 14 parts of fumaric acid and 160 parts of adipic acid were added as a dicarboxylic acid component, and the temperature was raised from 200 ° C to 220 ° C for 1 hour to carry out an esterification reaction. Next, the temperature was raised to 255 ° C, and the reaction system was slowly depressurized, and then reacted under a reduced pressure of 0.22 mmHg for 1 hour and 30 minutes to obtain a hydrophobic copolymerized polyester. The obtained hydrophobic copolymerized polyester had a weight average molecular weight of 20,000 and was pale yellow transparent.

<Grafting of radical polymerizable monomer>

In a reactor equipped with a stirrer, a thermometer, a reflux device and a quantitative dropwise addition device, 75 parts of the hydrophobic copolymerized polyester as described above, 56 parts of methyl ethyl ketone and 19 parts of isopropyl alcohol were charged. And heating and stirring at 65 ° C to dissolve the hydrophobic copolymerized polyester. After the hydrophobic copolymerized polyester was completely dissolved, 15 parts of maleic anhydride (MA) was added as a radical polymerizable monomer to the polyester solution. Next, 10 parts of styrene (ST) was used as a radical polymerizable monomer, and 1.5 parts of azobisdimethylvaleronitrile was dissolved as a graft polymerization initiator in 12 parts of methyl ethyl ketone. The obtained solution was added dropwise to the polyester solution at 0.1 ml/min, and stirring was continued for 2 hours. After taking the sample for analysis from the reaction solution, 5 parts of methanol was added. Next, 300 parts of water and 15 parts of triethylamine were added to the reaction solution, and stirred for 1 hour. Thereafter, the internal temperature of the reactor was raised to 100 ° C, and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off by distillation to obtain a water-dispersible polyester-based graft copolymer. The polyester-based graft copolymer was light yellow transparent and had a glass transition temperature of -10 °C.

(modulation of coating liquid 3)

The water-dispersible polyester-based graft copolymer as described above is diluted with water, and colloidal ceria and isopropanol are added to obtain a coating liquid having a solid concentration of 1% by weight (polyester-based graft copolymerization) Material: 1% by mass, colloidal cerium oxide: 1% by mass, water: 63% by mass, isopropyl alcohol: 35% by mass).

[Experimental Example 21]

On the single side of the polyester-based base film which is not extended as described above, the coating liquid 3 is applied by a gas knife coating method to form a solid component of the polyester-based graft copolymer, which becomes 0.006 g/m ² after drying, and The film was continuously introduced into a tenter to be preheated until the film temperature reached 70 ° C, and then extended 4.0 times in the transverse direction at a temperature of 72 ° C. Next, heat treatment was performed at 95 ° C for 14 seconds, followed by treatment at 50 ° C for 10 seconds to obtain a heat-shrinkable polyester film having a thickness of 45 μm. At this time, the heat transfer coefficient in the preheating step was 0.0009, and the heat transfer coefficient in the extending step was 0.0056. The physical property values of the film of the obtained film roll are shown in Table 4.

[Experimental Example 22]

In Experimental Example 21, except that the coating amount of the coating liquid 3 was changed so that the solid content of the polyester-based graft copolymer became 0.003 g/m ² after drying, heat shrinkage was obtained in the same manner as in Experimental Example 21. A polyester film. The physical property values of the film of the obtained film roll are shown in Table 4.

(Experimental Example 23 is inferior to Experimental Examples 21 to 22) [Experimental Example 23]

A heat-shrinkable polyester film having a thickness of 45 μm was obtained in the same manner as in Example 21 except that the coating liquid 3 was not applied. The physical property values of the film of the obtained film roll are shown in Table 4.

(Specially good experimental examples 24 to 25) (Modulation of polyester base film)

The pellets of polyesters A to C which were individually pre-dried were mixed at a ratio of A of 15% by weight, B of 75% by weight, and C of 10% by weight, and supplied to the extruder at 275 ° C. It was melt-extruded and quenched on a chill roll having a surface temperature of 25 ° C to obtain an unstretched polyester-based base film having a thickness of 180 μm. The obtained film was subjected to NMR analysis to investigate the composition thereof. The results are shown in Table 5.

(Modulation of polyester-based graft copolymer)

<Preparation of Hydrophobic Copolymerized Polyester>

In a stainless steel autoclave equipped with a stirrer, a thermometer, and a partial reflux cooler, 345 parts of dimethyl terephthalate (DMT) was added as a dicarboxylic acid component, and 211 parts of 1,4-butanediol. (BD), 270 parts of ethylene glycol (EG) as a diol component, and 0.5 part of tetra-n-butyl titanate as a polymerization catalyst, and a transesterification reaction was carried out from 160 ° C to 220 ° C for 4 hours. Next, 14 parts of fumaric acid and 160 parts of adipic acid were added as a dicarboxylic acid component, and the temperature was raised from 200 ° C to 220 ° C for 1 hour to carry out an esterification reaction. Next, the temperature was raised to 255 ° C, and the reaction system was slowly depressurized, and then reacted under a reduced pressure of 0.22 mmHg for 1 hour and 30 minutes to obtain a hydrophobic copolymerized polyester. The obtained hydrophobic copolymerized polyester had a weight average molecular weight of 20,000 and was pale yellow transparent.

<Grafting of radical polymerizable monomer>

In a reactor equipped with a stirrer, a thermometer, a reflux device and a quantitative dropwise addition device, 75 parts of the hydrophobic copolymerized polyester as described above, 56 parts of methyl ethyl ketone and 19 parts of isopropyl alcohol were charged. And heating and stirring at 65 ° C to dissolve the hydrophobic copolymerized polyester. After the hydrophobic copolymerized polyester was completely dissolved, 15 parts of maleic anhydride (MA) was added as a radical polymerizable monomer to the polyester solution. Next, 10 parts of styrene (ST) was used as a radical polymerizable monomer, and 1.5 parts of azobisdimethylvaleronitrile was dissolved as a graft polymerization initiator in 12 parts of methyl ethyl ketone. The obtained solution was added dropwise to the polyester solution at 0.1 ml/min, and stirring was continued for 2 hours. After the analysis sample was taken from the reaction solution, 5 parts of methanol was added. Next, 300 parts of water and 15 parts of triethylamine were added to the reaction solution, and stirred for 1 hour. Thereafter, the internal temperature of the reactor was raised to 100 ° C, and methyl ethyl ketone, isopropyl alcohol, and excess triethylamine were distilled off by distillation to obtain a water-dispersible polyester-based graft copolymer. The polyester-based graft copolymer was light yellow transparent and had a glass transition temperature of -10 °C.

(modulation of coating liquid 4)

The water-dispersible polyester-based graft copolymer as described above was diluted with water, and dodecylsulfonate was added thereto, and isopropyl alcohol was added thereto to obtain a coating liquid having a solid concentration of 3% by weight (polyester-based grafting). Copolymer: 2.6% by mass, antistatic agent: 0.4% by mass, water: 62% by mass, isopropyl alcohol: 35% by mass).

[Experimental Example 24]

When the coating liquid 4 is applied by a gas knife coating method to the single side of the polyester-based base film as described above, the polyester-based graft copolymer solid content becomes 0.03 g/m ² after drying, and The film was continuously introduced into a tenter to be preheated until the film temperature reached 70 ° C, and then extended 4.0 times in the transverse direction at a temperature of 72 ° C. Next, heat treatment was performed at 95 ° C for 14 seconds, followed by treatment at 50 ° C for 10 seconds for a heat-shrinkable polyester film having a thickness of 45 μm. At this time, the heat transfer coefficient in the preheating step was 0.0009, and the heat transfer coefficient in the extending step was 0.0056. The physical property values of the film of the obtained film roll are shown in Table 5.

Heat shrinkage rate difference / 15 ° C: [(thermal shrinkage in the transverse direction is more than 0% temperature + 10 ° C), the heat shrinkage ratio in the transverse direction] - [(the transverse shrinkage rate is more than 0% of the temperature -5 °C) Thermal contraction rate in the transverse direction]

TPA: terephthalic acid, EG: ethylene glycol, NPG: neopentyl glycol, BD: 1,4-butanediol

[Experimental Example 25]

In Example 24, heat shrinkage was obtained in the same manner as in Example 1 except that the coating amount of the coating liquid 4 was changed so that the solid content of the polyester-based graft copolymer was 0.004 g/m ² after drying. Polyester film. The physical property values of the film of the obtained film roll are shown in Table 5.

(Comparative Example 26 with respect to Experimental Examples 24 to 25) [Experimental Example 26]

A heat-shrinkable polyester film having a thickness of 45 μm was obtained in the same manner as in Experimental Example 24 except that the coating liquid 4 was not applied. The physical property values of the film of the obtained film roll are shown in Table 5.

[Industry use possibility]

The heat-shrinkable polyester film of the present invention can maintain a good appearance and is suitable for label use and has high industrial use value. Further, in addition to suppressing the occurrence of malfunction due to static electricity, it can also be made to have an anti-blocking property at a high temperature, and is also suitable for use in a label for a container for filling a high-temperature content.

Claims (11)

A heat-shrinkable polyester film comprising an anti-blocking improving layer on at least one side of a polyester-based base film, the anti-blocking improving layer comprising at least one radical polymerizable single a polyester-based graft copolymer obtained by grafting a hydrophobic copolymerized polyester; the heat shrinkage ratio in the main shrinkage direction when immersed in hot water of 95 ± 0.5 ° C for 10 seconds is 30 to 60%; The heat shrinkage in the main shrinkage direction begins when immersed in hot water, and the impregnation in hot water is any of the following: at 60 ± 0.5 ° C, 65 ± 0.5 ° C, 70 ± 0.5 ° C, 75 ± 0.5 ° C, 80 ± 0.5. Dipping in hot water at °C, 85±0.5°C, 90±0.5°C, and 95±0.5°C for 10 seconds; main shrinkage from [(the main shrinkage direction heat shrinkage rate exceeds 0% temperature +10 °C) The heat shrinkage rate in the direction minus the heat shrinkage rate in the main shrinkage direction of the heat shrinkage rate in the main shrinkage direction of -0 °C is less than 20%; and at 59.5 to 90.5 When immersed in hot water at any temperature of °C and at a constant temperature of ±0.5 °C for 10 seconds, the length in the direction orthogonal to the main shrinkage direction is elongated. The heat-shrinkable polyester film according to claim 1, wherein the anionic antistatic agent is present on at least one side. The heat-shrinkable polyester film according to claim 2, wherein the anionic antistatic agent has an alkyl group and has a carbon number of 10 to 20. The heat-shrinkable polyester film according to claim 1, wherein the radical polymerizable single system contains at least maleic anhydride and styrene Alkene. The heat-shrinkable polyester film according to claim 1, wherein an anti-blocking improving layer is provided on at least one side of the film, the anti-blocking improving layer comprising at least one radical polymerizable monomer A polyester-based graft copolymer obtained by grafting a hydrophobic copolymerized polyester, and an anionic antistatic agent is present in the anti-blocking modified layer. The heat-shrinkable polyester film according to claim 5, wherein the radical polymerizable single system contains at least maleic anhydride and styrene. The heat-shrinkable polyester film according to claim 5, wherein the anionic antistatic agent has an alkyl group and has a carbon number of 10 to 20. The heat-shrinkable polyester film according to any one of claims 1 to 2, wherein the heat shrinkage ratio in the main shrinkage direction when immersed in hot water of 80 ± 0.5 ° C for 10 seconds Less than 40%. The heat-shrinkable polyester film according to any one of the above-mentioned claims, wherein the heat-shrinkable polyester film has a haze of 10% or less after heat shrinkage. The heat-shrinkable polyester film according to any one of the above-mentioned items, wherein the heat-shrinkable polyester film is adhered to a non-chlorine-based organic solvent. A heat-shrinkable label produced by using the heat-shrinkable polyester film according to any one of claims 1, 2, and 5.