JP2005169904A - Thermally shrinkable polyester film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermally shrinkable polyester film which prevents the blocking of goods in a drink vending machine by improving slipping on the side to be an outer surface when used as the label of a container for drink and is good in transparency and excellent in processing aptitude, and to provide a method for producing the film. <P>SOLUTION: An easily slipping layer which contains a silicone component and in which a coated amount of a solid content is 0.002-0.5 g/m<SP>2</SP>is formed on at least one surface of a polyester film. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

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

  In recent years, heat-shrinkable plastic films have been used for the purpose of exterior packaging for improving the appearance of packages, packaging for avoiding direct impact on the contents, label packaging that protects glass bottles or plastic bottles, and displays products. Widely used. Plastic film materials used for these purposes include stretched films such as polyvinyl chloride films, polystyrene films, and polyester films, and labels for various containers such as polyethylene terephthalate (PET) containers, polyethylene containers, and glass containers. It is used for purposes such as cap seals and integrated packaging.

  However, although the polyvinyl chloride heat-shrinkable film is excellent in heat shrinkage properties, it has low heat resistance, and also has problems such as generation of hydrogen chloride gas during incineration and causing dioxins. In addition, when a polyvinyl chloride heat-shrinkable film is used as a heat-shrinkable label for a PET container or the like, there is a problem that when the container is recycled, the label (tubular label) and the container must be separated.

  On the other hand, polystyrene-based heat-shrinkable films can be evaluated for their good finished appearance after heat-shrinking, but they have poor solvent resistance, so that ink with a special composition must be used for printing. In addition, the polystyrene heat-shrinkable film needs to be incinerated at a high temperature, and has a problem that a large amount of black smoke and off-flavor are generated during incineration.

  Polyester-based heat-shrinkable films without these problems are highly expected as heat-shrink labels to replace polyvinyl chloride-based heat-shrinkable films and polystyrene-based heat-shrinkable films. The amount used is also increasing.

  However, the conventional polyester heat-shrinkable film has also been required to be improved in its properties. When beverages in glass bottles or plastic bottles sold at vending machines are sold with vending machines using a conventional polyester heat-shrinkable film as labels, the slipperiness of the labels is not sufficient and clogging occurs in the vending machines. That is, there has been a problem that the product does not pass through the passage and does not reach the exit, or the products are discharged multiple times.

There is a user's request to solve this problem by improving the slipperiness of the container label, and the overcoat agent layer having good slipperiness on the heat-shrinkable film surface obtained by stretching. The manufacturing method of the shrink label which laminates | stacks has been examined (refer patent document 1). However, since it is manufactured by post-processing on the film surface, there is a problem in terms of cost, and the surface of the roll and the film in the processing step for laminating an overcoat agent layer with good slipperiness on the heat-shrinkable film surface There remained problems such as wear debris generated by rubbing with the surface of the laminated layer, resulting in decreased productivity.
Japanese Patent Laid-Open No. 2002-196677

  The present invention has been made in view of the problems of the above-mentioned conventional polyester heat-shrinkable film, and when used as a label for a beverage container, the beverage is improved by improving the lubricity on the outer surface side. An object of the present invention is to provide a polyester heat-shrinkable film that prevents clogging of products in a vending machine, has good transparency, and has excellent processability, and a method for producing the same.

In order to achieve the above object, the polyester heat-shrinkable film of the present invention is an easy-to-use polyester component containing a silicone component on at least one surface and having a solid content coat amount of 0.002 to 0.5 g / m ² . A sliding layer is formed.
In addition, solid content coating amount means the quantity of the coating thing which exists on a polyester-type film after application | coating and drying.

  In this case, the hot water shrinkage rate in the main shrinkage direction at 95 ° C. of the polyester heat-shrinkable film can be 50% or more.

  Moreover, the friction coefficient (μd) between the easy-sliding layers of the polyester heat-shrinkable film can be set to μd ≦ 0.27.

  In addition, one surface and the other surface of the polyester heat-shrinkable film can have solvent adhesion.

Moreover, the silicone component content in the solid content of the easy-sliding layer of the polyester heat-shrinkable film can be 10 to 80% by weight, and the silicone component content can be 0.001 to 0.4 g / m ^2. .

  Moreover, the easy-slip layer of a polyester-type heat-shrinkable film can contain a silicone component and a binder resin component.

  The binder resin component of the polyester heat-shrinkable film can contain an ester resin.

  In addition, a polyester heat-shrinkable film is obtained by applying a coating liquid containing a silicone component to at least one surface of an unstretched polyester film or a uniaxially stretched polyester film and then stretching it at least uniaxially. be able to.

  Further, in the method for producing the polyester heat-shrinkable film, at least one surface of an unstretched polyester film or a uniaxially stretched polyester film is coated with a coating solution containing a silicone component, and then at least uniaxially stretched. It is characterized by that.

  According to the polyester heat-shrinkable film of the present invention, it is possible to keep the appearance of the film good and to keep the friction between the films low. Furthermore, when it is mounted as a label for a container such as a beverage container by heat shrinkage treatment with steam or hot air, the friction between the containers can be kept low, so that the product can be prevented from being clogged in the vending machine. Moreover, since it is excellent in the solvent adhesiveness of labels when using it as a label, mounting | wearing to a container is easy and it can be made into a thing with a very high practical value.

  Hereinafter, embodiments of the polyester heat-shrinkable film of the present invention will be described.

The polyester-based heat-shrinkable film of the present invention comprises a silicone component on at least one surface of a polyester-based film, and an easy-slip layer having a solid content coat amount of 0.002 to 0.5 g / m ² is formed. More specifically, it is obtained by using a homopolyester, a copolyester, or a mixture of two or more thereof, the main constituent unit of which is an ester unit formed from a known polycarboxylic acid component and a polyhydric alcohol component. The heat-shrinkable film has a silicone component and an easy-sliding layer having a solid content coating amount of 0.002 to 0.5 g / m ² formed on at least one surface of the polyester film.

  The polyester in the raw material composition used for the polyester film of the present invention is a homopolyester, a copolyester having a main constituent unit of a known polycarboxylic acid component and an ester unit formed from a polyhydric alcohol component, or A mixture of two or more thereof, and as such a polyester, a polyester containing a unit represented by an ethylene terephthalate unit, a butylene terephthalate knit, a trimethylene terephthalate unit, an ethylene-2,6-naphthalate unit or the like is shown. Can do.

  As the polyvalent carboxylic acid component forming the polyester, aromatic dicarboxylic acid, aliphatic dicarboxylic acid, alicyclic dicarboxylic acid and the like can be used. As the aromatic dicarboxylic acid component, isophthalic acid, orthophthalic acid, Benzene carboxylic acids such as 5-tert-butylisophthalic acid and 5-sodium sulfoisophthalic acid; naphthalenedicarboxylic acids such as 2,6-naphthalenedicarboxylic acid; 4,4′-dicarboxydiphenyl, 2,2,6,6- Dicarboxybiphenyls such as tetramethylbiphenyl-4,4′-dicarboxylic acid; 1,1,3-trimethyl-3-phenylindene-4,5-dicarboxylic acid and substituted products thereof; 1,2-diphenoxyethane- Examples include 4,4′-dicarboxylic acid and substituted products thereof.

  As fatty acid dicarboxylic acid components, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, pimelic acid, suberic acid, undecanoic acid, dodecanedicarboxylic acid, brassic acid, tetradecanedicarboxylic acid, Examples include tapsinic acid, nonadecanedicarboxylic acid, docosanedicarboxylic acid and substituted products thereof, 4,4′-dicarboxycyclohexane and substituted products thereof. Examples of the alicyclic carboxylic acid component include 4,4'-dicarboxydicyclohexyl dicarboxylic acid.

  In addition, as the polyhydric alcohol component, aliphatic diol, alicyclic diol, aromatic diol and the like can be used, and as the aliphatic diol component, diethylene glycol, propylene glycol, butanediol, 1,6-hexane. Diol, 1,10-decanediol, neopentyl glycol, 2-methyl-2-ethyl-1,3-propanediol, 2-diethyl-1,3-propanediol, 2-ethyl-2-n-butyl-1 , 3-propanediol and the like. Examples of the alicyclic diol include 1,3-cyclohexanedimethanol and 1,4-cyclohexanedimethanol. Furthermore, examples of the aromatic diol component include ethylene oxide adducts of bisphenol compounds such as 2,2-bis (4-β-hydroxyethoxyphenyl) sulfone; xylylene glycol. Polyalkylene glycols such as polyethylene glycol and polypropylene glycol can also be used as the diol component.

  The polyester contained in the raw material composition is composed of the acid component and the diol component. In order to adjust the polyester, one or more acid components are used to improve the properties as a heat-shrinkable film. Alternatively, it is preferable to use a combination of polyhydric alcohol components, and the type and content of monomer components to be combined may be appropriately determined based on desired film characteristics, economy, and the like. The raw material composition contains one or more polyesters. When the contained polyester is one kind, it is preferably a copolymerized polyester containing an ethylene terephthalate unit. When two or more kinds of polyesters are mixed and used, the copolymerized polyester and homopolyester are used. It is preferable to use a mixture having a desired composition. In general, the copolymer polyester has a low melting point, so that there are problems such as difficulty in handling when the coat layer is dried during film production. Therefore, homopolyester (polyethylene terephthalate, polyethylene naphthalate, poly (1,4-cyclohexenediethylene) It is preferable to use a mixture of terephthalate)) and copolymerized polyester. However, when it is set as a polyester-type heat-shrinkable film, it is preferable that 1-2 mol% of the whole polyester which comprises a film contains an aliphatic dicarboxylic acid unit. By controlling within this range, the thermal shrinkage start temperature can be controlled within a preferred range.

  Any of the polyesters in the raw material composition can be produced by a conventionally known method. For example, the polyester can be prepared using a direct esterification method in which a dicarboxylic acid and a diol are directly reacted, a transesterification method in which a dicarboxylic acid dimethyl ester is reacted with a diol, or the like. The adjustment may be performed by either a batch method or a continuous method.

  In addition to the polyester, various known additives may be added to the raw material composition as necessary. Examples of the additive include lubricants such as titanium dioxide, particulate silica, kaolin, and calcium carbonate; antistatic agents; anti-aging agents; ultraviolet absorbers; and colorants (dyes and the like).

  The raw material composition is formed into a film by a known method (for example, an extrusion method or a calendar method). The shape of the film is, for example, a flat shape or a tube shape, and is not particularly limited. As the stretching method, for example, a known method such as a roll stretching method, a long gap stretching method, a tenter stretching method, or a tubular stretching method can be employed. In any of these methods, stretching can be performed by uniaxial stretching, sequential biaxial stretching, simultaneous biaxial stretching, and combinations thereof.

  In the biaxial stretching, stretching in the vertical and horizontal directions may be performed simultaneously, or one of them may be performed first. It is preferable that the draw ratio is arbitrarily set in the range of 1.0 to 7.0 times, and the magnification in one predetermined direction is 3.5 times or more.

  In the stretching step, it is preferable to perform preheating at a temperature not lower than the glass transition temperature (Tg) of the polyester constituting the film and not higher than Tg + 80 ° C., for example. In the heat setting at the time of stretching, for example, it is recommended to pass the heating zone at 30 to 150 ° C. for about 1 to 30 seconds after stretching. Further, the film may be stretched at a predetermined degree before or after heat setting after stretching the film. Further, after the stretching, a step of cooling while applying a stress to the film while keeping the stretched or tensioned state, or a cooling step after releasing the tensioned state following the treatment may be added. Although the thickness of the film obtained is not specifically limited, Usually, it is preferable that it is the range of 6-250 micrometers.

The polyester heat-shrinkable film of the present invention can be obtained by laminating an easy-sliding layer containing a silicone component and having a solid content coating amount of 0.002 to 0.5 g / m ² on the polyester film surface. . The solid content coating amount is the amount of the coated product existing on the polyester film after coating and drying.

  As the slippery layer, one containing a silicone component and a binder resin component is recommended. In the present invention, the silicone component refers to organosiloxanes and has properties such as oil, rubber, and resin, which are called silicone oil, silicone rubber, and silicone resin, respectively. Since it has water repellent action, lubrication action, mold release action, etc., it is effective in reducing surface friction when laminated as a film surface layer.

  On the other hand, heat-shrinkable films are often used by being heat-shrinked using steam or hot air when used as a beverage container label, and steam or hot air is used for a slippery layer with low water resistance. The sliding property is significantly reduced by the heat shrink treatment. However, when the slippery layer contains a silicone component, good slipperiness can be maintained even after treatment with steam due to its water-repellent effect. For this purpose, it is recommended to include a silicone resin among the silicone components. Here, the silicone resin means that the organopolysiloxane has a three-dimensional network structure, and is laminated on the surface of the polyester heat-shrinkable film as an easy-sliding layer and then wound up as a roll to the back of the film that comes into contact. Transcription of is difficult to occur. Moreover, when using the polyester-type heat-shrinkable film of this invention as a label of a drink container, although a printing process is given, the printability in that case is favorable. Furthermore, those having a methyl group as an organic group are particularly recommended because they have excellent heat resistance and are suitable for use as labels for hot beverage containers.

The silicone component is preferably 10 to 80% by weight, particularly preferably 20 to 70% by weight, as the solid content of the easy-slip layer. If the content is less than 10% by weight, the effect of improving the slipperiness is small. On the other hand, if the content exceeds 80% by weight, transfer of the layer components of the applied easy-sliding layer tends to occur. In particular, in the solid content of the easy-slip layer, the silicone component content is 10 to 80% by weight, and the silicone component content is more preferably 0.001 to 0.4 g / m ² .

  Further, the silicone component and other lubricants may be used in combination. As the lubricant used in combination, paraffin wax, microwax, polyethylene wax, polypropylene wax, ethylene acrylic wax, stearic acid, behenic acid, 12-hydroxystearic acid, Stearic acid amide, oleic acid amide, erucic acid amide, methylenebis stearic acid amide, ethylene bis stearic acid amide, ethylene bis oleic acid amide, butyl stearate, stearic acid monoglyceride, pentaerythritol tetrastearate, hydrogenated castor oil, stearic acid Stearyl, siloxane, higher alcohol polymer, stearyl alcohol, calcium stearate, zinc stearate, magnesium stearate, lead stearate, etc. It is preferable to. Among these, the addition of a low molecular weight polyethylene wax can be expected to improve lubricity from the effect of preventing sticking by smoothing the surface of the slippery layer.

  In addition, inorganic particles such as silica, titania, mica, talc, calcium carbonate, organic particles such as polymethyl methacrylate (PMMA), styrene-divinylbenzene, formaldehyde resin, polyamideimide, benzoguanamine, or surface treated products thereof. Although it is possible to further improve the slipperiness by adding N, it is recommended to adjust the addition amount appropriately according to the requirement of transparency because the transparency of the film tends to decrease due to the formation of surface irregularities etc. Is done.

  Examples of the binder resin component include ester resins, amide resins, urethane resins, epoxy resins, phenol resins, acrylic resins, vinyl acetate resins, olefin resins such as polyethylene or polypropylene, cellulose resins, There are melamine resins, copolymers or modified resins thereof, and those that are curable by heat and light energy. In particular, ester resins, urethane resins, or copolymers thereof must be combined with a lubricant. It is recommended because it shows good lubricity and can be bonded with a solvent in tube processing. Furthermore, from the viewpoint of safety and environmental friendliness, it is preferable to use an aqueous dispersion. This binder resin component has an effect as a binder, and improves the adhesion of the slippery layer to the polyester film, and in addition, when stretching the film after laminating the slippery layer, a stretching aid for making a smooth surface. Also acts as an agent. Furthermore, when stretched, it is also effective in strengthening the surface layer.

Next, tube processing will be described. When producing a tubular label from the polyester-based heat-shrinkable film of the present invention, a tube-forming process is performed. At this time, the end of one surface of the film made into a cylindrical shape using a solvent and the other surface are formed. From the viewpoint of often adhering to the end, a solvent such as 1,3-dioxolane or tetrahydrofuran is applied to the end of one side of the film, and the end of the other side of the film is applied to the applied surface. It is preferable that the adhesion is strong when crimping and peeling in the main contraction direction. When the solvent adhesiveness is insufficient, there is a possibility that the label adhesive part may be peeled off when the label is heat-shrinked or when the beverage bottle is handled.

  As a method for forming the easy-sliding layer, an unstretched polyester film obtained by forming the polyester-based raw material composition into a film by a melt extrusion method or the like, or a uniaxially stretched polyester-based film obtained by stretching the unstretched polyester-based film uniaxially, It is preferable to apply the coating solution for forming a slippery layer to the film surface in a smooth and uniform thickness (in-line coating), and then further heat-draw in a uniaxial or biaxial direction. When such a method is used, since the coating layer itself is stretched following the film, the stretching heat treatment has the effect of improving the adhesion between the coating layer and the polyester film and further strengthening the coating layer. Examples of the coating method in which the slippery layer forming coating solution is applied to the film surface in a smooth and uniform thickness include a reverse roll method, an air knife method, a fountain method, and the like.

  As an embodiment of the present invention, an ester resin, a urethane resin, an acrylic resin or a copolymer thereof is used as a binder resin component, a silicone resin is used as a lubricant, and the surface of a polyester film is easily slipped by an inline coating method. It is particularly recommended to form a layer.

The easy-sliding layer is preferably 0.002 to 0.5 g / m ² as a coating amount (referred to as solid content coating amount) present on the polyester film after stretching and drying, and more preferably 0.003. ˜0.2 g / m ² . If it is less than 0.002 g / m ² , the frictional resistance becomes large, and if it exceeds 0.5 g / m ² , the transparency of the film is lowered, the adhesiveness with a solvent is lowered, the roll in the processing step, etc. And wear debris is generated due to rubbing of the laminated surface.

Thus, the polyester heat-shrinkable film of the present invention has an easy-sliding layer on the outermost layer on at least one surface of the polyester film, and the outermost layer on at least one surface of the polyester film has a silicone component. A heat-shrinkable film having an easy-slip layer having a solid content coat amount of 0.002 to 0.5 g / m ² , preferably a polyester heat-shrinkable film cut into a 10 cm × 10 cm square shape Is a film having a shrinkage ratio in the main shrinkage direction of 50% or more when immersed in hot water of 95 ° C. for 10 seconds.
Hot water shrinkage (%) = ((size before heating−size after heating) / size before heating) × 100

  If the hot water shrinkage of the polyester heat-shrinkable film is less than 50% in the present invention, the heat shrinkage of the film is insufficient, and when the container is shrunk as a label, it may not adhere to the container. This is not preferable because an appearance defect occurs. The hot water shrinkage rate is more preferably 52% or more, and further preferably 55% or more.

  Next, the contents and effects of the present invention will be described with reference to examples, but the present invention is not limited to the following examples without departing from the gist thereof. In addition, the measuring method of the characteristic value in this specification is as follows.

(Hot water shrinkage)
The stretched film was cut into a 10 cm × 10 cm square so that one side thereof was parallel to the film flow direction, and was immersed in a water bath heated to 95 ° C. for 10 seconds. Immediately after 10 seconds, the film was immersed in a separately prepared 23 ° C. water bath for 20 seconds, and then the length of the film in the main shrinkage direction was measured to obtain the heat shrinkage rate. In addition, the direction which contracted most among the flow direction of a film and the direction orthogonal to the flow direction was made into the main shrinkage direction.
Hot water shrinkage (%) = ((size before heating−size after heating) / size before heating) × 100

(Coefficient of friction)
The dynamic friction coefficient μd between the film surfaces was measured in an environment of 23 ° C. and 65% RH in accordance with JIS-K-7125. Further, the dynamic friction coefficient after the hot water treatment was measured by the same method as described above by treating the film in 80 ° C. hot water for 20 seconds and shrinking it by 10% in the main shrinkage direction.

(Haze)
The haze was measured according to JIS-K-6714 using a haze meter (manufactured by Nippon Seimitsu Co., Ltd.).
○: ≦ 8.0%
×:> 8.0%

(Solvent adhesive strength)
Sealing was performed by applying 1,3-dioxolane to the stretched film and bonding the two together. The seal portion was cut to a width of 15 mm in the main stretching direction of the film, and set in a universal tension tester STM-50 manufactured by Baldwin Co., Ltd., and measured at a tensile rate of 200 mm / min in a 180 ° peel test.
○: ≧ 4N / 15mm
×: <4N / 15mm

(Abrasion resistance)
For the abrasion resistance evaluation, the wear amount of the easy-sliding layer was measured using a dyeing friction fastness tester (manufactured by Yasuda Seiki Seisakusho). Using a friction piece (surface radius 45 mm, arc 50 mm, width 25 mm) in which two sheets of gauze and sandpaper with a particle size of # 1000 are attached in order so that the sandpaper becomes the surface, a film is placed on the test piece base (surface radius 200 mm). Set the film sample so that the surface with the smaller coefficient of friction between each other becomes the surface, process the sample under the conditions of load 400g, reciprocation distance 100mm, 30 reciprocation / minute, and processing unit unit before and after 10 reciprocation processing The change in weight per area (g / m ² ) was measured.

(Vending machine clogged)
After the film is formed into a tube-shaped label so that the easy-slip layer is on the outer surface, it is attached to the barrel of a 500 mL beverage PET bottle by heat shrinkage due to steam, and is put into and discharged from a vending machine. The number (number) of clogged out of 400 discharges was measured.

(Example 1)
(1) Manufacture of polyester and unstretched film Mixing 40% by weight of polyethylene terephthalate, 50% by weight of polyester consisting of 100% by mole of terephthalic acid, 30% by mole of neopentyl glycol and 70% by mole of ethylene glycol, and 10% by weight of polybutylene terephthalate The obtained polyester composition was melted at 280 ° C., extruded from a T-die, and quenched with a chill roll to obtain an unstretched film.

(2) Preparation of coating solution The solid content of the aqueous dispersion of dimethyl silicone resin and styrene-acrylic acid ester copolymer (Cretex KT-290, manufactured by Shin Chemical Laboratory Co., Ltd.) is 95% by weight in the solid content, and the surface activity. An IPA-water solution containing a solid content of 5% by weight of a solid agent (Megafac F442: manufactured by Dainippon Ink and Chemicals, Inc.) was used as a coating solution.

(3) Manufacture of coated film The coating solution prepared in (2) is applied to the unstretched film obtained in (1) by the fountain method, heated until the film temperature reaches 70 ° C, and then 4 in the transverse direction by a tenter. After stretching by a factor of 0, heat setting was performed at 80 ° C. to obtain a polyester heat-shrinkable film having a coating amount of 0.02 g / m ² and a thickness of 50 μm. Table 1 shows the results of testing the stretched film by the above method.

(Example 2)
(1) Preparation of coating liquid Solid content of silicone water dispersion (TSM6343: manufactured by Toshiba Silicone) is 40% by weight of solid content, and solid content of polyethylene wax aqueous dispersion (Hitech E-8237: manufactured by Toho Chemical Co., Ltd.) 15% by weight in solid content, 30% by weight in solid content of an ester resin aqueous dispersion (Vylonal MD1500: manufactured by Toyobo Co., Ltd.), surfactant (Megafac F442: manufactured by Dainippon Ink & Chemicals, Inc.) An IPA-water solution containing a solid content of 15% by weight in the solid content was used as a coating solution.

  Otherwise, a polyester heat-shrinkable film was obtained in the same manner as in Example 1. Table 1 shows the results of testing this film by the above method.

(Example 3)
(1) Preparation of coating liquid The solid content of the silicone water dispersion (TSM6343: manufactured by Toshiba Silicone) was 50% by weight in the solid content, and the solid content of the polyethylene wax aqueous dispersion (Hitech E-8237: manufactured by Toho Chemical Co., Ltd.). 15 wt% in solid content, solid content of ester resin aqueous dispersion (Vylonal MD1500: manufactured by Toyobo Co., Ltd.) is 30 wt% in solid content, and solid content of surfactant (TB214 Matsumoto Yushi Co., Ltd.) is in solid content. An IPA-water solution containing 5% by weight was used as a coating solution.

  Otherwise, a polyester heat-shrinkable film was obtained in the same manner as in Example 1. Table 1 shows the results of testing this film by the above method.

(Comparative Example 1)
In Example 1, a flat heat-shrinkable film was obtained in the same manner as in Example 1 except that the coating solution was applied after lateral stretching so that the coating amount was 0.7 g / m ² . Table 1 shows the results of testing this film by the above method.

(Comparative Example 2)
In Example 2, a flat heat-shrinkable film was obtained in the same manner as in Example 2 except that the coating amount was 0.001 g / m ² . Table 1 shows the results of testing this film by the above method.

(Comparative Example 3)
(1) Preparation of coating solution
In Example 3, the solid content of the polyethylene wax aqueous dispersion (Hitech E-8237: manufactured by Toho Chemical Co., Ltd.) was 30% by weight of the solid content, and the solid content of the ester resin aqueous dispersion (Vylonal MD1500 manufactured by Toyobo Co., Ltd.) was used. An IPA-water solution containing 50% by weight in solid content and 20% by weight in solid content of a surfactant (TB214: manufactured by Matsumoto Yushi Co., Ltd.) was used as a coating solution, and the coating amount was 0.01 g / m ² .

  Otherwise, a polyester heat-shrinkable film was obtained in the same manner as in Example 1. Table 1 shows the results of testing this film by the above method.

  When the obtained film rolls each having a level of 500 m × 2 were used and the printing machine was run at a line speed of 100 m / min, in Examples 1 to 3, no generation of wear debris was observed in all the guide rolls. When Comparative Example 1 is used, white powdered wear debris adheres to the metal guide roll (made of surface anodized, 740 mm diameter) in the portion close to unwinding among the rolls that come into contact with the slippery coating surface. It was confirmed visually.

  As described above, the polyester heat-shrinkable film of the present invention has been described based on a plurality of examples. However, the present invention is not limited to the configurations described in the above examples, and the configurations described in the respective examples. The configuration can be changed as appropriate within a range that does not depart from the spirit of the invention, such as appropriate combination.

  The polyester-based heat-shrinkable film of the present invention can maintain the appearance of the film satisfactorily and can keep the friction between the films low. Furthermore, when it is attached as a label for a container such as a beverage container by heat-shrinking treatment with steam or hot air, it has the characteristic that the friction between containers can be kept low. It can be used to prevent clogging of products in a vending machine, and can also be used for, for example, solid integrated packaging applications.

Claims (9)

A polyester-based heat-shrinkable material characterized in that an easy-sliding layer containing a silicone component and having a solid content coat amount of 0.002 to 0.5 g / m ² is formed on at least one surface of the polyester-based film. the film.   The polyester-based heat-shrinkable film according to claim 1, wherein the hot-water shrinkage in the main shrinkage direction at 95 ° C is 50% or more.   The polyester-based heat-shrinkable film according to claim 1, wherein a coefficient of friction (μd) between the easy-slip layers is μd ≦ 0.27.   4. The polyester heat-shrinkable film according to claim 1, 2 or 3, wherein one surface and the other surface have solvent adhesion. The silicone component content in the solid content of the easy-slip layer is 10 to 80% by weight, and the silicone component content is 0.001 to 0.4 g / m ^2. 4. The polyester heat-shrinkable film according to 4.   6. The polyester heat-shrinkable film according to claim 1, wherein the easy-sliding layer contains a silicone component and a binder resin component.   The polyester heat-shrinkable film according to claim 6, wherein the binder resin component is an ester resin.   2. An unstretched polyester film or a uniaxially stretched polyester film obtained by applying a coating liquid containing a silicone component to at least one surface and then stretching at least uniaxially. The polyester heat-shrinkable film according to 3, 4, 5, 6 or 7.   A method for producing a polyester heat-shrinkable film according to claim 1, 2, 3, 4, 5, 6, 7 or 8, wherein at least one surface of an unstretched polyester film or a uniaxially stretched polyester film, A method for producing a polyester heat-shrinkable film, wherein at least uniaxial stretching is performed after coating a coating solution containing a silicone component.