JPH1128795A - Packaging film with water-based ink printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packaging film printed by aqueous ink, contributing to improvements of operating environment and external environment by executing printing. SOLUTION: The packaging film comprises an easily adhesive polyester film having an easily adhesive coating layer containing dicarboxylic acid component having metal base and/or ammonium base of 5 to 20 mol.%, to total dicarboxylic acid component as dicarboxylic acid component and copolymerization polyester copolymerized by 20 to 100 mol.% of diethyleneglycol component to total glycol component and having a second order transition point of 15 to 100 deg.C as glycol component as main components and having a thickness of 0.005 to 0.3 μm and formed on at least one side surface of a polyester based film so that aqueous ink printing is executed on the coating layer of the film, and a heat sealing layer laminated on a printed surface of the polyester film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a packaging film. More specifically, the present invention relates to a packaging film that contributes to improvement of a working environment and an external environment by performing aqueous ink printing.

[0002]

2. Description of the Related Art Polyester films, especially polyethylene terephthalate films, have been used as components of many flexible packaging films because of their advantages in mechanical strength and thermal dimensional stability. On the other hand, many flexible packaging films are usually printed for display or aesthetic purposes, and are generally printed on the polyester film in the construction.

[0003] In order to improve the adhesion of the printing ink to the polyester film, a method of subjecting the surface of the polyester film to a corona discharge treatment, or a method of forming an easy-adhesion layer on the surface by using a polymer such as a urethane resin or a polyester resin. A method of forming a film and the like are conventionally known. Generally, the effect of improving the ink adhesiveness is higher in the easily adhesive polymer film layer than in the corona discharge treatment.

[0004]

In recent years, from the viewpoint of environmental protection, aqueous printing has been used in place of organic solvent-based printing inks for the purpose of improving the working environment of the printing process and the external environment such as exhaust and drainage. The motivation to use ink is growing. However, the conventional ink easy-adhesion polymer coating layer was developed for organic solvent-based printing inks, and the adhesiveness to aqueous printing inks was sometimes insufficient.

[0005] In any treatment, a polyester film as a product is required to have excellent anti-blocking properties which provide good long-term storage and handling properties. Furthermore, the polyester film for packaging is cut linearly when opened, and isotropic in molecular orientation so that twisting does not occur during bag making, transparency of the film, and easy handling in subsequent processes. Moderate slipperiness is required.

[0006] Therefore, an object of the present invention is to provide a packaging film having an aqueous ink printed on an easy-adhesion coating layer exhibiting excellent adhesiveness to an aqueous ink. Another object of the present invention is to provide the packaging film having excellent blocking resistance. Still another object of the present invention is to provide the above-mentioned packaging film having excellent linear cutability. Still other objects and advantages of the present invention will become apparent from the following description.

[0007]

According to the present invention, the above objects and advantages of the present invention are as follows: at least one side of a polyester base film is provided with a dicarboxylic acid component having a metal base and / or an ammonium base as a dicarboxylic acid component. The main component is a copolymerized polyester having a secondary transition point of 15 to 100 ° C in which a diethylene glycol component is copolymerized as a glycol component in an amount of 5 to 20 mol% with respect to a dicarboxylic acid component and 20 to 100 mol% as a glycol component. Aqueous ink printing is performed on the easy-adhesion coating layer of the easy-adhesion polyester film having the easy-adhesion coating layer having a thickness of 0.005 to 0.3 μm, and the printing surface of the printed polyester film is further heated. This is achieved by a packaging laminated film on which a sealing layer is laminated. Another object of the present invention is achieved by the above-described laminated film for packaging, wherein the easily adhesive coating layer contains 5 to 50% by weight of an acrylic polymer component. Still another object of the present invention is that the difference between the in-plane maximum refractive index and the minimum refractive index in the in-plane direction of the polyester base film is 0 to 0.05, and the angle between the orientation main axis and the transverse direction of the film is -40 to 40. 40
°, which is achieved by the above laminated film for packaging.

In the present invention, a dicarboxylic acid component having a metal base and / or an ammonium base as a dicarboxylic acid component is provided on at least one surface of a polyester base film described later in an amount of 5 to 20 parts with respect to all dicarboxylic acid components.
mol%, and a diethylene glycol component as a glycol component is 20 to 100 mol based on all glycol components.
1% copolymerized polyester having a secondary transition point of 15 to 100 ° C. having a thickness of 0.005 to 0.3 μm
m of an easily adhesive coating layer.

This copolymerized polyester comprises a dicarboxylic acid component and a glycol component, and a dicarboxylic acid component having a metal base and / or an ammonium base as the dicarboxylic acid component is 5 to 20 mol based on all dicarboxylic acid components.
1%, preferably 7 to 15 mol%, and the diethylene glycol component as a glycol component is 20 to 100 mol%, preferably 30 to 10 mol%, based on all glycol components.
It is a linear polyester containing 0 mol% as a copolymer component. Aqueous printing inks generally have a hydrophilic group in their binder to disperse well in an aqueous solvent, and it is necessary for the easily adhesive coating layer to have a sufficient hydrophilic group as well. . Therefore, the dicarboxylic acid component having a metal base and / or an ammonium base is 5 mol%.
When the content is less than 20% and / or the diethylene glycol component is less than 20 mol% as a glycol component, satisfactory adhesiveness cannot be obtained. On the other hand, when the content of the dicarboxylic acid component having a metal base and / or an ammonium base exceeds 20 mol%, the blocking resistance is poor, which is not preferable.

[0010] The secondary transition point of the above-mentioned copolymerized polyester is 15 to 100 ° C, preferably 20 to 80 ° C. If the secondary transition point of the copolymerized polyester is less than 15 ° C., the strength of the easily adhesive coating layer becomes extremely weak, and the lamination strength between the heat-sealable layer and the laminated layer is insufficient, or the layer is scraped off in a printing process or the like. There is a possibility of causing troubles such as. On the other hand, if the temperature is higher than 100 ° C., the adhesiveness with ink or a laminating adhesive is inferior.

As the dicarboxylic acid component having a metal base and / or an ammonium base described herein, an SO ₃ M group or a COOM group (M is Na, K, Li, NH
₄ ) etc., and specific examples include 5-sodium sulfoisophthalic acid.

The dicarboxylic acid component other than the dicarboxylic acid component having a metal base and / or an ammonium base of the copolymerized polyester includes terephthalic acid, isophthalic acid,
Orthophthalic acid, naphthalene-2,6-dicarboxylic acid,
Naphthalene-1,4-dicarboxylic acid, naphthalene-1,
Aromatic polycarboxylic acids such as 5-dicarboxylic acid, naphthalene-2,7-dicarboxylic acid, 4,4′-dicarboxylic biphenyl, trimellitic acid, pyromellitic acid, succinic acid, adipic acid, azelaic acid, and sebacic acid , Aliphatic polycarboxylic acids such as citric acid, cyclohexane-1,4
And alicyclic polycarboxylic acids such as dicarboxylic acids, and aromatic dicarboxylic acids are preferred. The aromatic dicarboxylic acid component accounts for 95 to 6 of all dicarboxylic acid components.
It is preferably 0 mol%, and when the aromatic dicarboxylic acid component exceeds 95 mol%, the adhesiveness is poor,
When the amount is less than 60 mol%, the blocking resistance is poor, so that it is not preferable.

The glycol components other than diethylene glycol include ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexane-1,4-dimethanol, polyethylene glycol, bisphenol A, bisphenol S, and glycerin. And polyols such as pentaerythritol.

Further, hydroxycarboxylic acids such as p-hydroxybenzoic acid, m-chloro-p-hydroxybenzoic acid, lactic acid, and ω-hydroxycaproic acid can be contained as a copolymer component, and can be in the form of a carbonate ester. Can also.

In the present invention, an anti-adhesion coating layer containing 5 to 50% by weight, preferably 5 to 25% by weight of an acrylic polymer component is formed in the above-mentioned anti-adhesion coating layer, so that the blocking resistance is improved. Excellent. If the acrylic polymer component is less than 5% by weight, no effect of improving the anti-blocking property is obtained, while if it exceeds 50% by weight, the adhesiveness to the ink deteriorates, which is not preferable. Such an acrylic polymer component preferably contains a self-crosslinking component such as 2-hydroxyethyl methacrylate or N-methylol methacrylamide in the copolymer composition from the viewpoint of the effect of improving blocking resistance. The acrylic polymer component has a secondary transition point of 15 to 1
The temperature is preferably 00 ° C, preferably 20 to 80 ° C, from the viewpoint of the effect of improving blocking resistance and ink adhesion.

In the easy-adhesion coating layer, other than the above-mentioned copolymerized polyester and acrylic polymer component, other resins, an antistatic agent, a colorant, a surfactant, an ultraviolet absorber, as long as the properties are not impaired. And the like can be appropriately added.

The above-mentioned copolyester or a composition of the copolyester with an acrylic polymer component and other components can be applied to a polyester base film described later as an aqueous liquid containing the same as a main component. preferable. The aqueous liquid is suitably in the form of an aqueous solution, aqueous dispersion, or emulsion.

The coating is applied to an unstretched polyester film, a uniaxially stretched polyester film, a biaxially stretched polyester film, and the like, and is preferably applied to a polyester base film stretched uniaxially in the longitudinal direction. After the application, transverse stretching, and in some cases, re-longitudinal stretching or re-lateral stretching can also be performed. The coating amount is such that the thickness of the easily adhesive coating layer is 0.005 to 0.3 μm, preferably 0.01 to 0.1 μm.
It is desirable that the amount be in the range of μm. If the thickness of the easily-adhesive coating layer is less than 0.005 μm, the adhesion to the ink will be insufficient, while if it exceeds 0.3 μm, the possibility of blocking will increase, which is not preferable.

In the present invention, aqueous ink printing is performed on the easy-adhesion coating layer of the easy-adhesion polyester film in which the easy-adhesion coating layer is formed on at least one surface of the polyester base film. The aqueous printing ink is not particularly limited, and may be a commercially available aqueous ink. As for the solvent for diluting the ink, an optimum solvent for the ink may be arbitrarily selected, but from the viewpoint of the present invention, 40% by weight of the solvent is used.
Preferably, the above is water. The printing method is not particularly limited, and a known method can be used. Specific examples include gravure printing, flexographic printing, and offset printing.

In the present invention, a heat-sealing layer is laminated on the easily-adhesive coating layer in order to form a sealed container by heat-sealing the laminated film for packaging of the present invention. The heat seal layer is not particularly limited as long as it can form a sealed container by heat fusion.
Examples include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene,
Polypropylene, copolymerized polypropylene, ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid copolymer resin, ethylene-ethyl acrylate copolymer resin, ethylene-methyl acrylate copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene Examples thereof include methyl methacrylate copolymer resin, ethylene / vinyl alcohol copolymer resin, ionomer resin, polyacrylonitrile, and copolyester. The method for laminating the heat seal layer on the easily adhesive coating layer is not particularly limited. Examples include a dry lamination method and an extrusion lamination method. The adhesive used in the dry lamination is not particularly limited, and a commercially available adhesive such as an imine-based, isocyanate-based, urethane-based, butadiene-based, or titanate-based adhesive can be used.

The polyester forming the polyester base film of the laminated film for packaging of the present invention is a saturated linear polyester comprising a dicarboxylic acid component and a glycol component. The dicarboxylic acid component includes aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalene-2,6-dicarboxylic acid, and 4,4′-dicarboxylic biphenyl, and the glycol components include ethylene glycol, tetramethylene glycol, and hexaethylene glycol. Aliphatic or alicyclic glycols such as methylene glycol and cyclohexane-1,4-dimethanol are preferred. Specific examples of the polyester include homopolymers such as polyethylene terephthalate and polyethylene-2,6-naphthalenedicarboxylate.

Further, the polyester base film may be a copolymer containing the above polyester as a main component, if necessary. Examples of monomers to be copolymerized include terephthalic acid, isophthalic acid, orthophthalic acid, naphthalene-2,6-dicarboxylic acid, naphthalene-1,4-dicarboxylic acid, naphthalene-1,5-dicarboxylic acid, naphthalene-2,7 -Dicarboxylic acid, 4,
Aromatic polycarboxylic acids such as 4'-dicarboxylic biphenyl, trimellitic acid, pyromellitic acid, etc .; aliphatic polycarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid and citric acid; cyclohexane-1, Alicyclic polycarboxylic acids such as 4-dicarboxylic acid, propylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, cyclohexane-
Polyols such as 1,4-dimethanol, diethylene glycol, polyethylene glycol, bisphenol A, bisphenol S, glycerin, pentaerythritol, p-hydroxybenzoic acid, and m-chloro-p-
Examples thereof include hydroxycarboxylic acids such as hydroxybenzoic acid, lactic acid, and ω-hydroxycaproic acid, and can also be in the form of a carbonate. Here, it is preferable that the above-mentioned copolymer containing polyester as a main component is a component whose main component occupies 70 mol% or more.

In the polyester base film, fine particles having an average particle size of preferably 0.05 to 2.0 μm, preferably 0.1 to 5 μm, are used as a surface roughening agent as long as the effects of the present invention are not impaired. 0.0% by weight. The fine particles may be internally precipitated particles or externally added particles. As the externally added particles, for example, calcium carbonate, magnesium carbonate, barium carbonate, barium sulfate, calcium phosphate, lithium phosphate, magnesium phosphate, lithium fluoride, aluminum oxide,
Examples include silicon oxide (silica), titanium oxide, kaolin, talc, carbon black, silicon nitride, boron nitride, and crosslinked polymer fine particles (for example, fine particles of crosslinked polystyrene, crosslinked acrylic resin, crosslinked silicone resin, and the like). These may be used alone or in combination of two or more.

As a method for incorporating such a surface roughening agent, an internal (particle) precipitation method in which an alkali (earth) metal compound is precipitated as fine particles by adding a phosphating compound during the production of polyester or the like, or a method for producing a polymer from a polymer production step. An external particle adding method in which inorganic or organic fine particles inert to the polymer are added in any of the film forming steps.

Further, a coloring agent, an antistatic agent, an antioxidant, a catalyst, other resins, and the like can be appropriately added to the polyester base film.

The polyester base film of the present invention comprises:
It is sufficient that the film has a thickness generally used as a packaging film, and is 5 to 200 μm, preferably 10 to 200 μm.
m thickness.

The above polyester base film can be produced by a conventionally known method. For example, the dried polyester is melted using a known extruder, the melted polyester is extruded into a sheet, and the unstretched sheet obtained by quenching and solidifying on a rotary cooling drum is biaxially stretched and biaxially stretched. A method of forming a stretched polyester film may be used. As the stretching method, a sequential biaxial stretching method or a simultaneous biaxial stretching method can be used, but the sequential biaxial stretching method is preferred from the viewpoint of workability in a coating step described later. As the stretching conditions in the sequential biaxial stretching method, the unstretched sheet is heated at a temperature of 60 to 130 ° C., preferably 90 to 125 ° C. for 2 hours.
延伸 6 times, preferably 2.5 to 4.0 times, and then stretched at 60 to 130 ° C., preferably 90
2 to 6 times, preferably 2.5 to 4.times.
Stretch 0 times. In addition, a method of performing unidirectional stretching in two or more stages may be used. Further, after the intermediate heat treatment after the second stage stretching, the film may be stretched again in the same direction as the first stage and / or in the same direction as the second stage. The biaxially stretched polyester film thus obtained is heated at 150 to 250 ° C.
Preferably, heat treatment is performed at a temperature of 180 to 230 ° C. for 1 to 10 seconds. At that time, limited shrinkage or elongation within 20%,
Alternatively, it may be performed under a fixed length, and may be performed in two or more stages.

In the present invention, the difference between the maximum refractive index in the in-plane direction and the minimum refractive index in the in-plane direction of the polyester base film is 0 to 0.05, and the angle between the main axis of alignment and the transverse direction of the film is -40 to 40. By setting the degree, twisting or the like does not occur at the time of bag making, and it is possible to obtain a packaging laminated film excellent in straight-line cutability. The difference between the in-plane direction maximum refractive index and the minimum refractive index and the angle between the orientation principal axis and the transverse direction of the polyester base film, the difference between the in-plane direction maximum refractive index and the minimum refractive index is 0 to 0.05, The stretching method described above may be applied so that the angle between the main orientation axis and the transverse direction of the film is −40 to 40 °. If the difference between the maximum refractive index and the minimum refractive index in the in-plane direction exceeds 0.05, or the angle between the orientation main axis and the transverse direction of the film is less than -40 ° or exceeds 40 °, the heat convergence during bag making. It is not preferable because twisting due to anisotropy occurs and it is not possible to cut straight when opening.

Further, in the present invention, by setting the haze of the polyester base film to 0 to 10%,
A laminated film for packaging having excellent transparency can be obtained. The degree of haze may be adjusted by adjusting the particle size and content of the above-mentioned surface roughening agent so that the degree of haze is in the range of 0 to 10%. Those having a haze of more than 10% are not preferable from the viewpoint of visual recognition of contents and aesthetic appearance.

Further, in the present invention, by setting the static friction coefficient of the polyester base film to 0.25 to 0.60, it is possible to obtain a packaging laminated film excellent in slipperiness. The static friction coefficient may be adjusted by adjusting the particle size and content of the above-mentioned surface roughening agent so that the static friction coefficient is in the range of 0.25 to 0.60. If the coefficient of static friction is less than 0.25, troubles such as misalignment of the end face of the product roll and difficulty in loading the bag may occur, and if it exceeds 0.60, the product roll may be wrinkled or promote blocking. Is not preferred.

[0031]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention. The various physical properties and characteristics in the present invention were measured and defined as follows.

(1) Intrinsic viscosity ([η]) It is a value (unit: dl / g) measured at 25 ° C. using o-chlorophenol as a solvent.

(2) Secondary transition point (T _g ) The aqueous solution of the copolymerized polyester or the acrylic copolymer was sufficiently dried to dryness, and 10 mg of the aqueous solution was transferred to a thermal analysis system (SSC / 5200, DSC5200, manufactured by Seiko Instruments Inc.). The sample is heated in a nitrogen gas stream at a heating rate of 20 ° C./min, and the endothermic behavior accompanying the glass transition (secondary transition) of the sample is analyzed by the first and second derivatives, and the temperature-endothermic curve is determined. The temperature indicating the shoulder is determined, and this is defined as T _g (unit: ° C.).

(3) Thickness of easy-adhesion coating layer (t) Application amount (w, unit: g / m ² ) of the above-mentioned aqueous liquid before drying, concentration of aqueous liquid (c, unit:% by weight), easy-adhesion coating layer After drying, the density (ρ, unit: g / cm ³ ) and the film stretching area ratio (R) between the aqueous liquid coating step and the winding step after the film formation step during the film formation step were measured, and the following formula was used. (Unit: μm). t = (w · c) / (ρ · R)

(4) Physical properties of polyester base film a) Difference between maximum refractive index and minimum refractive index in the in-plane direction (Δn) Surface of polyester base film using methylene iodide using a known Abbe refractometer Measure the refractive index in the inward direction. The film is rotated every 15 ° to measure the refractive index, and the difference between the maximum value and the minimum value is defined as Δn. b) Angle (θ) between main axis of orientation and lateral direction of polyester base film The polyester base film and the polarizing plate are overlapped and observed with transmitted light. The polarizing plate is rotated, and the angle at which the transmitted light becomes the brightest is defined as θ (unit: °, positive angle counterclockwise from the lateral direction of the film). It is preferable to use a known polarization microscope. c) Haze (H) Measured using a well-known integrating sphere haze meter (unit:%). d) Coefficient of static friction (μ _S ) The polyester base film is put on the front and back sides, a 1 kg weight is placed on one of the films, and one of the films is pulled. The tensile load when the film starts moving is measured with a load cell to obtain μ _S.

(5) Practical Characteristics of Laminated Film for Packaging a) Evaluation of Adhesive Strength When laminating an easily-adhesive polyester film and a heat seal layer, a part that is not adhered is provided, and the part is known as a gripping margin. T-peel test (peel speed: 300 mm / min) using a tensile tester of No. A: The heat seal layer is broken. B: Peeled, but peeled off at the interface between the heat seal layer and the adhesive or cohesive failure of the adhesive. C: The ink is cohesively broken and peeled. D: The ink completely transfers to the heat seal layer and peels off. ... A to B satisfy practical performance, and A is particularly preferable. b) Evaluation of anti-blocking property 6 kg / c with the front and back of the easily adhesive polyester film overlapped
It is pressurized to m ² and left for 17 hours in a well-known constant temperature and humidity chamber set at 60 ° C. and 80% RH. The film thus taken out is subjected to T-type peeling (peel speed: 100 mm / min) using a well-known tensile tester, and the peel strength is measured. A: Peeling force is less than 2 g / cm width B: Peeling force is 2 g / cm width or more and less than 3 g / cm width C: Peeling force is 3 g / cm width or more D: Completely blocking, and the film is broken at the time of peeling. ... A to B satisfy practical performance, and A is particularly preferable. c) Evaluation of straight-line cut property The heat-sealing layers of the laminated film for packaging are superimposed on each other, and 180 mm in 15 mm width 10 mm inward from one end.
Thermocompression bonding is performed at 1 ° C. and 1 kg / cm ² . A 20 mm cut is made in the heat-sealed end perpendicular to the heat seal, and a trouser-type tear test (tension speed: 200 mm / min) is performed using a well-known tensile tester. A: Tears perpendicular to the heat seal. B: The angle between the tear and the vertical line is less than 20 °. C: The angle between the tear and the vertical line is 20 ° or more. ... A to B satisfy practical performance, and A is particularly preferable.

Example 1 A sufficiently dried polyethylene terephthalate ([η] =
0.65) The resin is supplied to an extruder, melt-extruded from a slit die, and laminated with a low-density polyethylene film “V-1” manufactured by Tamapoly Co., Ltd. using a well-known roll laminator. Nip temperature: 80 ° C,
Nip pressure: 5 kg / cm width). It was left at 40 ° C. for 3 days to obtain a laminated film for packaging. Table 3 shows the practical characteristics of this laminated film for packaging. As is clear from Table 3, the laminated film for packaging of Example 1 satisfied all the required characteristics.

Example 2 As the copolymerized polyester constituting the easily adhesive coating layer, a copolymer of a dicarboxylic acid component of 90 mol% of terephthalic acid and 10 mol% of 5-sodium sulfoisophthalic acid, a glycol component of 65 mol% of ethylene glycol and 35 mol% of diethylene glycol was used. Polyester ([η]
= 0.45, T _g = 65 ° C), and a biaxially stretched easily adhesive polyester film having a thickness of 12 µm having an easily adhesive coating layer of 0.02 µm was obtained in the same manner as in Example 1. . Table 1 shows the component ratio, the intrinsic viscosity [η], and the secondary transition point T _g of the copolymerized polyester, and Table 2 shows the constituent components of the easily adhesive coating layer, the thickness t of the easily adhesive coating layer, and the physical properties of the polyester base film. Further, a laminated film for packaging was obtained in the same manner as in Example 1. Table 3 shows the practical characteristics of this laminated film for packaging. As is clear from Table 3, the packaging laminated film of Example 2 also satisfied all the required characteristics.

Example 3 Example 1 was repeated except that the composition of the easy-adhesion coating layer was changed to 90% by weight of copolymerized polyester and 10% by weight of polyoxyethylene nonylphenyl ether without using copolymerized acrylic.
A biaxially stretched easily adhesive polyester film having a thickness of 12 μm having an easily adhesive coating layer having a thickness of 0.02 μm was obtained in the same manner as described above. Table 1 shows the component ratio, the intrinsic viscosity [η], and the secondary transition point T _g of the copolymerized polyester, and Table 2 shows the constituent components of the easily adhesive coating layer, the thickness t of the easily adhesive coating layer, and the physical properties of the polyester base film. Further, a laminated film for packaging was obtained in the same manner as in Example 1. Table 3 shows the practical characteristics of this laminated film for packaging. As is evident from Table 3, the laminated film for packaging of Example 3 was slightly inferior in blocking resistance, but satisfied the required properties for the time being.

Example 4 The same procedure as in Example 1 was carried out except that the sampling range of the easy-adhesion polyester film was 5 to 15% of the total width from both ends, and the thickness of the easy-adhesion polyester film was 0.012 μm.
A μm biaxially stretched easily adhesive polyester film was obtained. Table 1 shows the component ratio, the intrinsic viscosity [η], and the secondary transition point T _g of the copolymerized polyester, and Table 2 shows the constituent components of the easily adhesive coating layer, the thickness t of the easily adhesive coating layer, and the physical properties of the polyester base film. Further, a laminated film for packaging was obtained in the same manner as in Example 1. Table 3 shows the practical characteristics of this laminated film for packaging.
To As is clear from Table 3, the laminated film for packaging of Example 4 was slightly inferior in straight-line cutability, but satisfied the required properties for the time being.

COMPARATIVE EXAMPLE 1 As the copolymerized polyester constituting the easily adhesive coating layer, the dicarboxylic acid component was composed of 85 mol% of terephthalic acid, 13 mol% of isophthalic acid and 2 mol% of 5-sodium sulfoisophthalic acid, and the glycol component was composed of 70 mol% of tetraethylene glycol. 0.02 μm-thick easy-coating film in the same manner as in Example 1 except that a copolymerized polyester ([η] = 0.62, T _g = 25 ° C.) containing 30 mol% of a bisphenol A-ethylene glycol adduct was used. A 12 μm-thick biaxially-stretched easily-adhesive polyester film having a layer was obtained. Table 1 shows the component ratio, the intrinsic viscosity [η], and the secondary transition point T _g of the copolymerized polyester, and Table 2 shows the constituent components of the easily adhesive coating layer, the thickness t of the easily adhesive coating layer, and the physical properties of the polyester base film. Example 1
In the same manner as in the above, a laminated film for packaging was obtained. Table 3 shows the practical characteristics of this laminated film for packaging. As is clear from Table 3, the laminated film for packaging of Comparative Example 1 was inferior in adhesiveness because the copolymerization amount of 5-sodium sulfoisophthalic acid and diethylene glycol did not satisfy the essential requirements of the present invention.

Comparative Example 2 As the copolymerized polyester constituting the easily adhesive coating layer, the dicarboxylic acid component was 98 mol% of terephthalic acid and 2 mol% of 5-sodium sulfoisophthalic acid, the glycol component was 50 mol% of tetraethylene glycol, 20 mol% of diethylene glycol and bisphenol. A 0.02 μm-thick easily-adhesive coating layer in the same manner as in Example 1 except that a copolymerized polyester ([η] = 0.68, T _g = 24 ° C.) containing 30 mol% of A-ethylene glycol adduct was used. A biaxially stretchable polyester film having a thickness of 12 μm and having a thickness of 12 μm was obtained. Table 1 shows the component ratio, the intrinsic viscosity [η], and the secondary transition point T _g of the copolymerized polyester, and Table 2 shows the constituent components of the easily adhesive coating layer, the thickness t of the easily adhesive coating layer, and the physical properties of the polyester base film. Example 1
In the same manner as in the above, a laminated film for packaging was obtained. Table 3 shows the practical characteristics of this laminated film for packaging. As is evident from Table 3, the laminated film for packaging of Comparative Example 2 was also poor in adhesiveness because the copolymerization amount of 5-sodium sulfoisophthalic acid did not satisfy the essential requirements of the present invention.

Comparative Example 3 As the copolymerized polyester constituting the easily adhesive coating layer, the dicarboxylic acid component was 50 mol% of terephthalic acid, 35 mol% of isophthalic acid and 15 mol% of 5-sodium sulfoisophthalic acid, the glycol component was 70 mol% of ethylene glycol and bisphenol. A-polyethylene copolymer adduct of 30 mol% ([η] =
0.40, T _g = 65 ° C.)
A biaxially stretched easily adhesive polyester film having a thickness of 12 μm having an easily adhesive coating layer having a thickness of 0.02 μm was obtained in the same manner as described above. Table 1 shows the component ratio, the intrinsic viscosity [η], and the secondary transition point T _g of the copolymerized polyester, and Table 2 shows the constituent components of the easily adhesive coating layer, the thickness t of the easily adhesive coating layer, and the physical properties of the polyester base film. Further, a laminated film for packaging was obtained in the same manner as in Example 1. Table 3 shows the practical characteristics of this laminated film for packaging. As is clear from Table 3, the laminated film for packaging of Comparative Example 3 was inferior in adhesion since the copolymerization amount of diethylene glycol did not satisfy the essential requirements of the present invention.

Comparative Example 4 As the copolymerized polyester constituting the easily adhesive coating layer, the dicarboxylic acid component was composed of 75 mol% of terephthalic acid and 25 mol% of 5-sodium sulfoisophthalic acid, and the glycol component was composed of 70 mol% of ethylene glycol and 30 mol% of diethylene glycol. Copolyester ([η] =
Example 1 except that 0.43, T _g = 45 ° C.) was used.
A biaxially stretched easily adhesive polyester film having a thickness of 12 μm having an easily adhesive coating layer having a thickness of 0.02 μm was obtained in the same manner as described above. Table 1 shows the component ratio, the intrinsic viscosity [η], and the secondary transition point T _g of the copolymerized polyester, and Table 2 shows the constituent components of the easily adhesive coating layer, the thickness t of the easily adhesive coating layer, and the physical properties of the polyester base film. Further, a laminated film for packaging was obtained in the same manner as in Example 1. Table 3 shows the practical characteristics of this laminated film for packaging. As is clear from Table 3, the packaging laminated film of Comparative Example 4 was inferior in blocking resistance because the copolymerization amount of 5-sodium sulfoisophthalic acid did not satisfy the essential requirements of the present invention.

Comparative Example 5 A 12 μm-thick polyester film having a thickness of 12 μm was prepared in the same manner as in Example 1 except that the aqueous liquid coating for forming the easily adhesive coating layer was not performed, and the uniaxially stretched polyester base film was stretched directly in the transverse direction. An axially stretched polyester base film was obtained. Table 2 shows the physical properties of this polyester base film. Further, a laminated film for packaging was obtained in the same manner as in Example 1. Table 3 shows the practical characteristics of this laminated film for packaging. As is evident from Table 3, the laminated film for packaging of Comparative Example 5 did not have an easily adhesive coating layer and did not satisfy the essential requirements of the present invention, so that it was poor in adhesiveness.

Comparative Example 6 The procedure of Example 1 was repeated except that the conditions for applying the aqueous liquid were adjusted so that the thickness of the easily adhesive coating layer was 0.4 μm.
A 2 μm biaxially stretched easily adhesive polyester film was obtained.
Table 1 shows the component ratio, the intrinsic viscosity [η], and the secondary transition point T _g of the copolymerized polyester, and Table 2 shows the constituent components of the easily adhesive coating layer, the thickness t of the easily adhesive coating layer, and the physical properties of the polyester base film. Further, a laminated film for packaging was obtained in the same manner as in Example 1. Table 3 shows the practical characteristics of this laminated film for packaging. As is clear from Table 3, the laminated film for packaging of Comparative Example 6 was inferior in blocking resistance because the thickness of the easily adhesive coating layer did not satisfy the essential requirements of the present invention.

Comparative Example 7 A biaxially stretched easily adhesive polyester film having a thickness of 12 μm was obtained in the same manner as in Example 1 except that an aqueous urethane resin solution was applied as the easily adhesive coating layer. Table 2 shows the constituent components of the easy-adhesion coating layer, the thickness t of the easy-adhesion coating layer, and the physical properties of the polyester base film. Further, a laminated film for packaging was obtained in the same manner as in Example 1. Table 3 shows the practical characteristics of this laminated film for packaging. As is clear from Table 3, the laminated film for packaging of Comparative Example 7 was inferior in adhesiveness to the aqueous ink because the components of the easily adhesive coating layer were different from the essential requirements of the present invention.

Comparative Example 8 A film having a thickness of 12 μm was prepared in the same manner as in Example 1 except that an aqueous solution of a polyvinyl alcohol resin was applied as the easily adhesive coating layer.
Was obtained. Table 2 shows the constituent components of the easy-adhesion coating layer, the thickness t of the easy-adhesion coating layer, and the physical properties of the polyester base film. Example 1
In the same manner as in the above, a laminated film for packaging was obtained. Table 3 shows the practical characteristics of this laminated film for packaging. As is clear from Table 3, since the component of the easy-adhesion coating layer of the packaging laminated film of Comparative Example 8 is different from the essential requirement of the present invention, the adhesiveness with the aqueous ink is excellent, but the adhesion with the base film is excellent. As a result, the adhesiveness as a whole was poor.

Examples 5 to 8 and Comparative Examples 9 to 16 Polyethylene-2,6-naphthalene dicarboxylate ([η] =
0.65), the longitudinal stretching temperature was 130 ° C., the transverse stretching temperature was 140 ° C., and the heat treatment temperature was 24 ° C.
Except that the film was subjected to a 3% relaxation treatment in the width direction at 0 ° C., the thickness was 12 in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 8, respectively.
A biaxially stretched easily-adhesive polyester film or a biaxially stretched polyester base film of μm was obtained. Table 1 shows the component ratio, the intrinsic viscosity [η], and the secondary transition point T _g of the copolymerized polyester, and Table 2 shows the constituent components of the easily adhesive coating layer, the thickness t of the easily adhesive coating layer, and the physical properties of the polyester base film. Further, a laminated film for packaging was obtained in the same manner as in Example 1.
Table 3 shows the practical characteristics of this laminated film for packaging.

[0050]

[Table 1]

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[Table 2]

[0052]

[Table 3]

[0053]

According to the present invention, there is provided a laminated film for packaging which has high adhesiveness between the easily-adhesive coating layer and the aqueous ink and can prevent the printing ink from peeling off, thereby improving the working environment and the external environment. Can contribute.

Continued on the front page (72) Inventor Masayuki Fukuda 3-37-19 Koyama, Sagamihara-shi, Kanagawa Teijin Limited Sagamihara Research Center

Claims (7)

[Claims] At least one surface of a polyester base film contains a dicarboxylic acid component having a metal base and / or an ammonium base as a dicarboxylic acid component in an amount of 5 to 20 mol% based on all dicarboxylic acid components, and a diethylene glycol component as a glycol component. The primary component is a copolymerized polyester having a secondary transition point of 15 to 100 ° C copolymerized with 20 to 100 mol% with respect to the glycol component,
Water-based ink printing is performed on the easy-adhesion coating layer of the easy-adhesion polyester film having the thickness of 0.005 to 0.3 μm, and further on the printing surface of the printed polyester film. A laminated film for packaging on which a heat seal layer is laminated. 2. The copolymerized polyester according to claim 1, wherein the dicarboxylic acid component having a metal base and / or an ammonium base is 5 to 20 mol% and the aromatic dicarboxylic acid component is 95 to 60%. mol
The laminated film for packaging according to claim 1, which is: 3. The laminated film for packaging according to claim 1, wherein the easily adhesive coating layer contains 5 to 50% by weight of an acrylic polymer component. 4. The difference between the maximum refractive index in the in-plane direction and the minimum refractive index in the in-plane direction of the polyester base film is 0 to 0.05, and the angle between the principal axis of alignment and the transverse direction of the film is −40.
The laminated film for packaging according to any one of claims 1 to 3, wherein the angle is 40 to 40 °. 5. The packaging laminated film according to claim 1, wherein the polyester base film has a haze of 0 to 10%. 6. The packaging laminated film according to claim 1, wherein the polyester base film has a coefficient of static friction of 0.25 to 0.60. 7. The method according to claim 7, wherein the metal base and / or ammonium base is SO ₃ M and / or COOM (where M is N
a, K, is at least one indicating a) selected from the group consisting of Li and NH _4, laminated packaging film according to any one of claims 1 to 6.