KR20130068928A - Heat shrinkable polyester film with superior adhesion to solvent - Google Patents

Abstract

PURPOSE: A heat shrinkable polyester film is provided to have excellent adhesion and labeling performance while maintaining physical properties of a film. CONSTITUTION: A heat shrinkable polyester film is that at least two layers including at least one outermost layer are co-extruded and satisfies a formula: thickness of an inner layer >= whole thickness of the outermost layer ×10. The inner layer is a copolymer polyester resin of a terephthalic acid or dimethyl terephthalte-containing dicarboxylic acid, and ethylene glycol and neopentyl glycol-containing diol. The outermost layer is a polymer of a dicarboxylic acid including terephthalic acid or dimethylterephthalte, and diol including ethylene glycol.

Description

Heat-shrinkable polyester film with excellent solvent adhesion {HEAT SHRINKABLE POLYESTER FILM WITH SUPERIOR ADHESION TO SOLVENT}

The present invention relates to a heat-shrinkable polyester film having excellent solvent adhesion, and more particularly, excellent general adhesiveness and labeling property of the solvent, maintaining the intrinsic properties of the film, and using general PET without additives in the outermost layer. The present invention relates to a heat-shrinkable polyester film having excellent solvent adhesion, thereby reducing the adhesive coating process.

Generally, heat-shrinkable films are widely used for labeling for plastic bottles and glass bottles, for cap-seals, for packaging batteries, and for directly packing multiple containers by using the property of shrinkage by heating . In order to use the heat-shrinkable film for various packaging materials or labels, the heat-shrinkable film should have excellent sealing properties, uniformity of shrinkage, etc. as well as basic properties such as heat resistance, chemical resistance, weather resistance, and printing characteristics.

Conventional heat-shrinkable films used polyvinyl chloride-based, polystyrene-based, polypropylene-based, polyethylene-based, etc., polyvinyl chloride-based film was very poor environmental friendliness due to problems such as chlorine gas and dioxin generation during incineration. In particular, the polystyrene-based film can be evaluated in terms of good finishing appearance after shrinkage. However, since it has poor solvent resistance, it is required not only to use a special composition ink at the time of printing but also to have a problem in that it is difficult to store because of its high natural shrinkage ratio. In addition, polypropylene was poor in shrinkage at low temperatures, and wrinkles and stains were likely to occur in the shrinkage area. In addition, the above-mentioned films have a disadvantage in that they are insufficient in heat resistance and are liable to be melted or ruptured during the boiling treatment or the retort treatment, so that it is difficult to maintain the film state.

Therefore, in recent years, the research on the polyester film which does not have the above-mentioned problem is being actively conducted, and it is expected to be a very shrinkable label to replace the polyvinyl chloride film or the polystyrene film, and to increase the usage of PET containers. Therefore, the usage is also gradually increasing.

On the other hand, since a commonly used heat shrinkable polyester film is polyethylene terephthalate, polyethylene terephthalate, which is a semi-crystalline polymer, can not obtain a sufficient heat shrinkage ratio, various techniques for overcoming this have been developed. As one example thereof, in Japanese Patent Laid-Open Nos. 57-42726, 57-159510 and 59-97175, a heat shrinkable polyester film has a sufficient shrinkage rate and an amorphous nose to control shrinkage stress, shrinkage rate, and the like. Disclosed is a uniaxial stretching of a polyester, an amorphous copolyester and a crystalline copolyester or a blend of two or more crystalline polyesters in a longitudinal or transverse direction. Also, Korean Patent Laid-Open Publication No. 2001-0098502 discloses a heat shrinkable polyester film having a light transmittance of 0 to 20% at a wavelength of 380 nm, a light transmittance of 0 to 60% at a wavelength of 400 nm, and a film haze of 15% Based on the total amount of the heat-shrinkable polyester film.

However, the polyester film produced by the above-described method may be somewhat improved in shrinkage uniformity only by process control, but the low solvent adhesiveness of the film during packaging may cause labels to be difficult to commercialize. In addition, the uniaxially oriented film has a problem that product chain value of the product is lowered because the chain of the polymer is oriented in only one direction, so that the adhesive part bursts due to friction, impact, or external force during heat shrinkage and thermal history. .

Japanese Patent Laid-Open No. 57-42726 Japanese Patent Application Laid-Open No. 57-159510 Japanese Patent Application Laid-Open No. 59-97175 Korean Patent Laid-Open Publication No. 2001-0098502

The present invention has been made to solve the above problems, the object of the present invention is excellent solvent adhesion and labeling properties, can maintain the intrinsic properties of the film, the use of ordinary PET without additives in the outermost layer By reducing the adhesive coating process, it is to provide a heat-shrinkable polyester film having excellent solvent adhesion with excellent product price competitiveness.

These and other objects and advantages of the present invention will become more apparent from the following description of a preferred embodiment thereof.

The object is that at least two layers including an inner layer and at least one outermost layer provided on the inner layer are coextruded, and satisfy the following Equation 1,

(1)

Thickness of inner layer ≥ total thickness of outermost layer X 10

It is achieved by the heat shrinkable polyester film which is excellent in the solvent adhesive force characterized by the above-mentioned.

Here, the inner layer is a heat-shrinkable polyester resin of 70 to 100 mol% of a copolymer polyester resin obtained by copolymerizing a composition of dicarboxylic acid containing terephthalic acid or dimethyl terephthalate and a diol containing ethylene glycol and neopentyl glycol. The outermost layer is characterized in that it is a polyester resin as a polymer polymer of dicarboxylic acid containing terephthalic acid or dimethyl terephthalate and diol containing ethylene glycol.

Preferably, the copolyester resin of the inner layer is a resin obtained by copolymerizing 100 mol% of terephthalic acid as a dicarboxylic acid component, 50 to 90 mol% of ethylene glycol as a diol component and 10 to 50 mol% of neopentyl glycol. It is done.

Preferably, the outermost layer is a polyethylene terephthalate (PET) resin, the number of carboxyl groups which are terminal groups satisfy the following Equation 2,

(2)

20 eq / ton ≤ end group number of PET ≤ 50 eq / ton

.

Preferably, the heat shrinkage nonuniformity in the main shrinkage direction of the heat-shrinkable polyester film excellent in solvent adhesion is 10% or less.

Preferably, the heat-shrinkable polyester film having excellent solvent adhesion is characterized in that the thickness nonuniformity in the longitudinal direction or the transverse direction is 10% or less.

Preferably, the heat shrinkable polyester film having excellent solvent adhesion is characterized in that the maximum heat shrinkage stress in the main shrinkage direction is 1.2 kgf / mm 2 or less.

Preferably, the heat-shrinkable polyester film having excellent solvent adhesion has a strength in the main shrinkage direction of 10 to 30 kgf / mm 2 after crystallization, and an elongation in the direction orthogonal to the main shrinkage direction is 10 to 500%. It is done.

According to the present invention, it is excellent in solvent adhesion and labeling properties, can maintain the intrinsic properties of the film, by using a general PET without additives in the outermost layer can reduce the easy-adhesive coating process, etc., excellent product price competitiveness Has the effect of.

Hereinafter, the present invention will be described in detail with reference to embodiments and drawings of the present invention. It will be apparent to those skilled in the art that these embodiments are provided by way of illustration only for the purpose of more particularly illustrating the present invention and that the scope of the present invention is not limited by these embodiments .

The heat-shrinkable polyester film having excellent solvent adhesion according to the present invention is coextruded with at least two layers including an inner layer and at least one outermost layer provided on the inner layer, and the following Equation 1 is satisfied. .

(1)

Thickness of inner layer ≥ total thickness of outermost layer X 10

The heat-shrinkable polyester film having excellent solvent adhesiveness according to the present invention satisfies the range of Equation 1 because when the thickness of the outermost layer (surface layer) is thick, it is difficult to realize physical properties such as shrinkage rate and cause uneven shrinkage. It is important to do. In addition, the structure of the heat-shrinkable polyester film excellent in solvent adhesion according to the present invention may be a two-layer structure formed with the outermost layer on one side of the inner layer, may be a three-layer structure formed with the outermost layer on both sides of the inner layer, the inner layer It may be a three-layered structure having two outermost layers formed on one surface thereof, or a structure composed of four or more layers provided with three or more outermost layers on or between the inner layers.

In addition, the inner layer is preferably a heat-shrinkable polyester resin of 70 to 100 mol% of a copolymer polyester resin obtained by copolymerizing a composition of dicarboxylic acid containing terephthalic acid or dimethyl terephthalate and diol containing ethylene glycol and neopentyl glycol. Do. Preferably, the copolyester resin of the inner layer is a resin obtained by copolymerizing 100 mol% of terephthalic acid as a dicarboxylic acid component, 50 to 90 mol% of ethylene glycol as a diol component and 10 to 50 mol% of neopentyl glycol. desirable.

The outermost layer is preferably a polyester resin as a polymer polymer of dicarboxylic acid containing terephthalic acid or dimethyl terephthalate and diol containing ethylene glycol. In addition, the number of carboxyl groups which are terminal groups of the polyester resin used in the outermost layer preferably satisfies Equation 2 below, and most preferably, the polyester resin is polyethylene terephthalate (PET) resin.

(2)

20 eq / ton ≤ end group number of PET ≤ 50 eq / ton

In the outermost layer according to the present invention, it is preferable to position the PET having a carboxyl group (terminal group) controlled to 20 to 50 eq / ton, as shown in Equation 2 above, when the terminal group is less than 20 eq / ton through polymerization time control. -Adhesion with Dioxalane solvent is lowered, and if it exceeds 50 eq / ton, crystallinity may be increased and cracking may occur, and both strength and elongation may be reduced, thereby degrading the value of the product.

The carboxyl group of the outermost layer resin is evaluated in the polymerized chip unit. This correlates with the adhesion to 1,3-Dioxalane.

In addition, the heat shrinkable polyester film having excellent solvent adhesion according to the present invention has a heat shrinkage nonuniformity of 10% or less in the main shrinkage direction, a thickness nonuniformity of 10% or less in the longitudinal or transverse direction, and a maximum in the main shrinkage direction. It is preferable that thermal contraction stress is 1.2 kgf / mm <2> or less.

In addition, the heat-shrinkable polyester film having excellent solvent adhesion according to the present invention has a strength in the main shrinkage direction of 10 to 30 kgf / mm 2 after crystallization treatment, and preferably 10 to 500% of the elongation in the direction orthogonal to the main shrinkage direction. Do.

Next, the manufacturing method of the heat shrinkable polyester film excellent in the solvent adhesive force which concerns on this invention is demonstrated.

First, the outermost layer (surface layer) uses terephthalic acid or dimethyl terephthalate of a dicarboxylic acid component, ethylene glycol is used as a diol component as a raw material, and the carboxyl group (terminal group) is 20 to 50 eq / ton by controlling the polymerization time. The HOMO-PET layer prepared by using a carboxyl group (terminal group) is less than 15 eq / ton in the inner layer, terephthalic acid or dimethyl terephthalate of a dicarboxylic acid component is used, and ethylene glycol and neopentyl glycol are used as a diol component. To polymerize the copolyester resin, and then blend the copolyester resin and the polybutylene terephthalate resin or the polytriethylene terephthalate resin in an appropriate mixing ratio to melt coextrude the outermost layer and the inner layer to prepare a sheet. Heat-shrinkable pole with excellent solvent adhesion by stretching in at least one of the longitudinal and transverse directions It would be to prepare a polyester film.

More specifically, a melt sheet was prepared by melt extrusion at 230 ° C. to 300 ° C. using a twin screw extruder while placing a PET layer having many terminal groups in the outermost layer and a copolyester composition in the inner layer and removing moisture by high vacuum. Next, it is cooled to obtain a polyester sheet, and the obtained sheet is stretched 2.0 to 7.0 times in either the direction of the film or the width direction of the film or in both directions within the glass transition temperature (Tg) + 60 ° C. If the draw ratio is less than 2.0, the stretching effect is not obtained. If the draw ratio exceeds 7.0, breakage of the film may occur because the yield point is exceeded, and sufficient shrinkage may not be obtained. Preferably, the glass is stretched in the range of 3.0 to 4.0 times within the glass transition temperature + 30 ° C. Thereafter, heat setting is performed at 60 ° C to 120 ° C, more preferably at 60 ° C to 90 ° C to obtain a heat shrinkage ratio of the film. If it is less than 60 ° C, it is difficult to obtain the effect of heat setting, and if it is 120 ° C or more, the film is crystallized and a sufficient shrinkage rate cannot be obtained. If the thermal contraction rate is less than 30%, when the container is coated, there is a high possibility that a problem of loosening of the coating occurs because sufficient shrinkage does not occur.

Co-polyester resin which forms the inner layer of this invention is manufactured by copolymerization of a dicarboxylic acid and a diol component. The dicarboxylic acid is preferably terephthalic acid or dimethyl terephthalate alone, isophthalic acid, 2 to 80 to 100 mol% of terephthalic acid or dimethyl terephthalate alone or a mixture thereof relative to 100 mol% of the total dicarboxylic acid. , 6-naphthalenedicarboxylic acid, sebacic acid, adipic acid, diphenyldicarboxylic acid, 5-tert-butylisophthalic acid, 2,2,6,6-tetramethyldiphenyl-4,4'-dica Leric acid, 1,1,3-trimethyl-3-phenylindan-4,5-dicarboxylic acid, 5-sodium sulfoisophthalic acid, trimellitic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, blood It may be composed of 0 to 20 mol% of any one or more compounds selected from the group consisting of meric acid, azelaic acid, pyromellitic acid, 1,4-cyclohexanedicarboxylic acid, and 1,3-cyclohexanedicarboxylic acid. In addition, the diol component is at least one compound 10 selected from the group consisting of 50 to 90 mol% ethylene glycol, neopentyl glycol, 1,4-cyclohexane dimethanol, diethylene glycol, propanediol and butanediol based on 100 mol% of total diol To 50 mol% is mixed, more preferably, 50 to 90 mol% of ethylene glycol is mixed with 10 to 50 mol% of neopentin glycol to prepare a film has a high elongation in the main shrinkage direction and the direction perpendicular to the It is desirable to obtain low shrinkage stress values.

Further, the polyester resin constituting the outermost layer of the present invention is preferably a PET layer having many carboxyl groups, and co-extruded 100 mol% of the outermost layer and the copolymerized polyester resin of the inner layer to produce a heat shrinkable polyester film. A solvent adhesive force can be improved by utilizing the polyester resin with many carboxyl groups in an outermost layer.

The heat-shrinkable polyester film produced by the above method preferably has a thickness of 15 탆 to 130 탆. When the thickness is within this range, the heat shrinkable polyester film is excellent in stretch uniformity. When used for labeling or food packaging, It is excellent in the properties of barrier, moisture and gas.

Heat shrinkage of the heat-shrinkable polyester film excellent in solvent adhesion according to the present invention is measured as in the following experimental example, if the difference in heat shrinkage is more than 5%, the shrinkage rate during heat shrinkage is insufficient to lift the label It is preferable that the difference in thermal shrinkage rate is 5% or less because defects such as distortion of the label may occur due to shrinkage unevenness.

In addition, if the strength in the film's main shrinkage direction is less than 10 kgf / mm2, there is a risk of the film breaking during the printing process, and if the strength exceeds 30kgf / mm2, the heat shrink stress is increased and the container shrinks as a heat shrinkable label. Since the value of the product decreases, such as deformation, insufficient capacity of the content, and distortion of the label, it is not preferable. Therefore, the strength in the main shrinkage direction of the heat-shrinkable polyester film excellent in solvent adhesion according to the present invention is 10 kgf / mm 2 to 30 kgf / It is preferable that it is mm <2>.

In addition, when the elongation in the direction perpendicular to the film's main shrinkage direction is less than 10%, when it is used as a label for beverages, the product value is damaged due to cracking, impact, external force, etc. when filling or transferring the contents. The elongation in the direction orthogonal to the main shrinkage direction of the heat-shrinkable polyester film excellent in solvent adhesiveness according to the present invention is 10% or more, more preferably 50% or more.

In addition, the heat-shrinkable polyester film according to the present invention, after immersing for 10 seconds under no load in hot water maintained at 90 ° C of hot water, the heat shrinkage ratio uniformity in the main shrinkage direction is preferably 0 to 10%, the value Since smaller is more preferable, there is no restriction on the lower limit. The method of measuring the heat shrinkage nonuniformity in the experimental example is described. If the non-uniformity of heat shrinkage in the main shrinkage direction of the polyester film exceeds 10%, the warpage phenomenon may occur due to shrinkage nonuniformity during heat shrinkage, resulting in a problem that the value of the product is lowered.

In addition, the heat shrinkable polyester film according to the present invention preferably has a thickness nonuniformity of 10% or less in the longitudinal direction or the transverse direction, and the smaller the value thereof, the more preferable, and therefore there is no limitation on the lower limit. The thickness nonuniformity is described by measuring in the experimental example. If the thickness nonuniformity in the longitudinal or transverse direction of the heat-shrinkable polyester film exceeds 10%, the printability is particularly poor in printing a multicolored pattern in the printing process, and overlaps a plurality of colors. A shift is easy to occur at the time. Further, in order to produce a label from the film of the present invention, it is difficult to superimpose the film-adhered portions when the solvent is adhered and subjected to the tube-forming process. In addition, when the film is rolled up in a film manufacturing process, there is a difference in the partial winding hardness, resulting in loosening or wrinkling of the film, making it impossible to use the film as a heat shrinkable film.

In addition, the heat shrinkable polyester film according to the present invention preferably has a maximum heat shrinkage stress in the main shrinkage direction of 1.2 kgf / mm 2 or less. If the maximum heat shrinkage stress exceeds 1.2 kgf / mm 2, shrinkage as a heat-shrinkable label made from a film is not preferable because the value of the product is reduced, such as deformation of the container, insufficient capacity of the contents, and distortion of the label.

In addition, the heat-shrinkable polyester film according to the present invention has a strength in the main shrinkage direction of 10 kgf / mm 2 or more, an elongation in the direction orthogonal to the main shrinkage direction, and crystallization before the crystallization of the polyester film. After the treatment, the strength in the main shrinkage direction is 10 to 30 kgf / mm 2, and the elongation in the direction orthogonal to the main shrinkage direction is preferably 10 to 500%. If the elongation in the main shrinkage direction and the orthogonal direction is less than 10% after crystallization, when used as a beverage label, the product value is damaged because of cracking, impact, external force, etc. Not preferred.

Hereinafter, the structure and effect of the present invention will be described in more detail with reference to examples and comparative examples. However, this embodiment is intended to explain the present invention more specifically, and the scope of the present invention is not limited to these embodiments.

[Example]

In Example 1, a heat-shrinkable polyester film having excellent solvent adhesion in a three-layer structure was produced. The outermost layer of the film was prepared by shortening the reaction time using a composition of a dicarboxylic acid component, 100 mol% of terephthalic acid, a diol component, and 100 mol% of an ethylene glycol unit, thereby controlling the terminal group to 35 eq / ton and the IV to 0.55. A polyester resin was used, and the inner layer portion of the film was 0.70 dl / intrinsic viscosity obtained by copolymerizing a composition of a dicarboxylic acid component, 100 mol% of terephthalic acid, a diol component, 82 mol% of ethylene glycol units, and 18 mol% of neopentyl glycol units. g was used to prepare a copolyester resin. Subsequently, the outermost layer portion of the film places the polyester resin having many terminal groups, and the inner layer portion of the film places the copolyester resin, and the ratio of outermost layer thickness: inner layer thickness: outermost layer thickness is 1: 22: 1, Melt coextrusion at 285 ° C. to produce a melted sheet, followed by cooling to obtain an unstretched film having a thickness of 180 μm. The pre-stretched film was preheated to 90 ° C., stretched 3.6 times at a glass transition temperature of + 20 ° C. in the longitudinal or transverse direction, and then cooled to 60 ° C. to prepare a heat shrinkable polyester film having excellent solvent adhesion with a thickness of 50 μm. .

Comparative Example 1

In Comparative Example 1, a heat-shrinkable polyester film was prepared in the same manner as in Example 1 except that the ratio of the outermost layer thickness: inner layer thickness: outermost layer thickness was 1: 10: 1.

Comparative Example 2

This Comparative Example 2 was prepared in the same manner as in the manufacturing method of the Example using only the inner polyester copolymer of the inner layer without the outermost layer used in the Example to prepare a heat-shrinkable polyester film of a single layer.

Using the heat-shrinkable polyester film excellent in solvent adhesion according to the above Examples and Comparative Examples 1, 2 measured physical properties through the following experimental example and the results are shown in Table 1 below.

[Experimental Example]

(1) Heat shrinkage

After the film was cut into 10 cm × 10 cm squares, the film was immersed for 10 seconds without load in hot water maintained at a temperature of 90 ° C., and then the length was measured to determine the heat shrinkage rate according to Equation 3 below.

(3)

(2) Heat shrinkage unevenness degree

A film sample (total length of 2000 m or more, sample number of 40 or more) is taken in a film roll made by winding a film in a unit of 50 m. Each film sample was cut into 10 cm × 10 cm squares, and then heat shrinkage in the main shrinkage direction was measured for 10 seconds in hot water at 90 ° C. to obtain thermal shrinkage nonuniformity according to Equation 4 below.

(Equation 4)

Unevenness of heat shrinkage (%) =

Smax is the maximum heat shrinkage in the main shrinkage direction of the film, Smin is the minimum heat shrinkage in the main shrinkage direction of the film, and Smean is the average heat shrinkage in the main shrinkage direction of the film.

(3) Over time storage conditions

The product was stored in a thermo-hygrostat (TH-G, manufactured by Jitec Corp.) maintained at a temperature of 40 ° C and a humidity of 70% for 30 days, and then the physical properties thereof were measured.

(4) Strength (Tensile Strength)

The film was cut into a length of 200 mm and a width of 12.1 mm in a direction perpendicular to the main shrinkage direction to obtain a sample, and the sample device was placed in an upper and lower jack of a tensile tester (UTM machine manufactured by United), which set the sample to 100 mm. The strength was measured in the main contraction direction at a speed of 200 mm / min.

(5) Elongation at Break

The film was cut into a length of 200 mm and a width of 12.1 mm in the main shrinkage direction to obtain a sample, and the sample device was placed in a top and bottom jack of a tensile tester (UTM machine manufactured by United) set at 100 mm, and the tensile speed was 200 mm at room temperature. The elongation was measured for the principal shrinkage direction and orthogonal direction at / min.

(6) Thickness non-uniformity

Using a continuous measuring device (manufactured by Mahhrgmbh) for the film thickness was measured in accordance with the following equation 5 after measuring the thickness of the film in units of 5 cm on the length 3m along the longitudinal and transverse direction of the film.

(5)

Thickness non-uniformity (%) =

Where Tmax is the maximum thickness of the film, Tmin is the minimum thickness of the film, and Tmean is the average thickness of the film.

(7) Solvent adhesion property

1,3-Dioxalane was applied to the above-prepared film with a width of 1 cm and then adhered with the same film, and the adhesive strength was measured after one day.

division Example Comparative Example 1 Comparative Example 2 Heat Shrinkage (%) MD 1.1 0.8 1.0 TD 62.1 57.2 62.2 Strength in the main shrinkage direction (kgf / mm ² ) 29.4 25.2 29.2 Elongation in the direction orthogonal to the main shrinkage direction (%) 490 465 495 Thickness non-uniformity MD 2.1 2.0 2.3 TD 2.5 2.2 3.1 Solvent Adhesion (g / cm) 110 105 21

As can be seen in Table 1, when the outermost layer has a lot of carboxyl groups (terminal groups), it was confirmed that the solvent adhesion of 1,3 Dioxalane is increased. In the present invention, the outermost layer (surface layer) can be found to be able to solve the weak adhesion problem causing problems in the product while maintaining the intrinsic properties of the copolyester film by placing a lot of carboxyl groups.

It is to be understood that the present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention.

 The present invention is excellent in industrial value as a heat-shrinkable polyester film having excellent solvent adhesiveness made by controlling the composition of the polymer layer phase, controlling the carboxyl group (terminal group), and characterizing the film forming process in the manufacturing process.

Claims (8)

In the heat-shrinkable polyester film excellent in solvent adhesion,
At least two layers including an inner layer and at least one outermost layer provided on the inner layer are coextruded, and satisfy the following Equation 1,
(1)
Thickness of inner layer ≥ total thickness of outermost layer X 10
The heat-shrinkable polyester film excellent in solvent adhesiveness characterized by the above-mentioned. The method of claim 1,
The inner layer is a copolymerized polyester resin obtained by copolymerizing a composition of dicarboxylic acid containing terephthalic acid or dimethyl terephthalate and diol containing ethylene glycol and neopentyl glycol,
The outermost layer is a heat-shrinkable polyester film having excellent solvent adhesion, characterized in that the polyester resin as a high molecular polymer of diol containing terephthalic acid or dimethyl terephthalate and diol containing ethylene glycol. The method of claim 2,
The copolymer polyester resin of the inner layer is a resin obtained by copolymerizing 100 mol% of terephthalic acid as a dicarboxylic acid component, 50 to 90 mol% of ethylene glycol as a diol component and 10 to 50 mol% of neopentyl glycol. Heat-shrinkable polyester film with excellent adhesion. The method of claim 2,
The outermost layer is a polyethylene terephthalate (PET) resin, the number of carboxyl groups that are terminal groups satisfy the following formula (2),
(2)
20 eq / ton ≤ end group number of PET ≤ 50 eq / ton
The heat-shrinkable polyester film excellent in solvent adhesiveness characterized by the above-mentioned. 5. The method according to any one of claims 1 to 4,
A heat shrinkable polyester film having excellent solvent adhesion, wherein the heat shrinkage nonuniformity in the main shrinkage direction of the heat shrinkable polyester film excellent in solvent adhesion is 10% or less. 5. The method according to any one of claims 1 to 4,
The heat-shrinkable polyester film excellent in solvent adhesion is a heat shrinkable polyester film excellent in solvent adhesion, characterized in that the thickness nonuniformity in the longitudinal direction or the transverse direction is 10% or less. 5. The method according to any one of claims 1 to 4,
The heat-shrinkable polyester film excellent in solvent adhesiveness has a maximum heat shrinkage stress in the main shrinkage direction of 1.2 kgf / mm 2 or less, wherein the heat-shrinkable polyester film excellent in solvent adhesion is excellent. 5. The method according to any one of claims 1 to 4,
The heat-shrinkable polyester film having excellent solvent adhesion has a strength in the main shrinkage direction of 10 to 30 kgf / mm 2 after crystallization, and an elongation in the direction orthogonal to the main shrinkage direction is 10 to 500%. Heat-shrinkable polyester film with excellent adhesion.