JPH11300917A - Easy-adhesive transparent vapor deposition polyester film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyester film suitably used as a base material of a transparent vapor deposition film vapor-deposited by oxide such as silicon oxide or aluminum oxide excellent in gas barrier properties suitable as a packaging film, especially, a food packaging film. SOLUTION: An easy-adhesive transparent vapor deposition polyester film is constituted by forming a polyurethane resin layer on at least the single surface of a film wherein the deformation ratios (σ%) in the longitudinal and lateral directions of the film at a time when load of 5.0 N/m is applied to the film and the temp. of the film is raised at a temp. rising speed of 10-20 deg.C/min so that the deformation ratio σ1 thereof is 01.8-0.7% within a temp. range of 60-140 deg.C and the deformation ratio σ2 thereof is 02.6-1.0% within a temp. range of 140-180 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is a packaging BACKGROUND OF THE INVENTION, especially suitable gas barrier property superior silicon oxide as a food packaging film (SiO _x), as a substrate for a transparent vapor deposited film of oxide is deposited, such as aluminum oxide The present invention relates to a biaxially stretched polyester film suitably used.

[0002]

2. Description of the Related Art In order to preserve food for a long period of time, in order to block oxygen and water vapor from the outside air which promotes spoilage and deterioration,
It is necessary to use a packaging material having excellent gas barrier properties.
Aluminum foil, aluminum evaporated film, polyvinylidene chloride coated film, ethylene vinyl alcohol laminated film, etc. are used as gas barrier materials for packaging applications. The use of materials that generate incineration residues such as described above and materials that generate chlorine gas during incineration, such as polyvinylidene chloride, have been reduced. In addition, it is estimated that the use of dioxins, whose emission is regulated in incinerators, will be further reduced due to concerns. Also,
The aluminum foil and the aluminum vapor-deposited film have problems that the contents cannot be seen and that the heat treatment cannot be performed by a microwave oven. Under such circumstances, the transparent deposited film obtained by depositing an oxide such as silicon oxide or aluminum oxide on the base film can be checked for its contents because it is transparent,
Further, since it has excellent water resistance, the deterioration of gas barrier performance after retort treatment is small, and it can be applied to a microwave oven.

[0003] Among the base films, polyester films represented by polyethylene terephthalate (PET) are particularly excellent in heat resistance, dimensional stability, thickness uniformity, etc., and are used as base films for various metal deposition films. And widely used for oxide deposition.

[0004]

However, when a polyester film is used for depositing an oxide,
There is a problem that the gas barrier performance of the vapor-deposited film is not always sufficient, and there is a problem that the gas barrier performance varies, and further improvement of the gas barrier performance is required with the improvement of food quality.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above problems, and as a result, as a base film, the deformation rate of the film when the temperature was raised under a constant load was specified. And that a biaxially stretched polyester film having a polyurethane resin layer formed on the film surface to be subjected to the vapor deposition processing can be used to obtain a transparent vapor deposited film having excellent gas barrier performance. The present invention has been reached.

That is, the gist of the present invention is as follows. A load of 5.0 N / m is applied to the film, and the temperature rise rate is 1
0 to 20 ° C. / vertical and horizontal deformation of the film when it was elevated min (sigma%) is, deformation ratio sigma ₁ in the range of temperature 60 to 140 ° C. is -1.8～0.7% And in the temperature range of 140 to 180 ° C., the deformation ratio σ ₂ is −2.6 to
A polyester film for easy-adhesion transparent vapor deposition in which a polyurethane resin layer is formed on at least one surface of a film having a range of 1.0%.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the temperature ranges defining the deformation ratio of the film in the present invention, the temperature range of 60 to 140 ° C. is a temperature range corresponding to the step of winding the film after deposition, and the temperature range is 140 to 180 °.
C is a temperature range corresponding to the step of performing the vapor deposition processing.
If the deformation ratio σ ₁ and σ ₂ of the film in each temperature range deviate from the range specified in the present invention, wrinkles occur during the running of the film, unevenness or omission occurs in the deposited film,
As a result, there arises a problem that the gas barrier performance of the vapor-deposited film is reduced or the gas barrier performance varies.

In the present invention, PET is most suitable as the polyester used as the base film.
Isophthalic acid, as long as the effects of the present invention are not impaired,
Other dicarboxylic acid components such as naphthalenedicarboxylic acid, adipic acid, sebacic acid, and other glycol components such as butanediol, neopentyl glycol, and bisphenol A may be copolymerized, and two or more of these components may be used in combination. You may. In addition, polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polycyclohexylene dimethylene terephthalate (PC
It can be used by blending with another polyester such as T).

The polyester film of the present invention is produced by melt-extruding an unstretched sheet of polyester and biaxially stretching the resulting unstretched sheet in the machine and transverse directions using a tenter-type biaxial stretching method or an inflation method. can do. For example, when a tenter-type biaxial stretching method is used, the unstretched sheet is brought into close contact with a cooling drum whose temperature has been adjusted to room temperature or lower, cooled, and stretched at a stretching temperature of 90 to 90 ° C.
120 ° C., stretching ratio in the MD and TD directions of 2.5 to 2.5
After stretching about 4.5 times, the TD can be manufactured by performing a heat treatment at 235 to 250 ° C. for 1 to 10 seconds at a relaxation rate of 1 to 7%. A polyester film having the properties specified in the present invention is produced by appropriately combining these conditions.

In the present invention, the polyester film has an average particle diameter of 0.001 to 5 μm, preferably 0.0 to 5 μm.
A lubricant of 1 to 1 μm is added in an amount of 0.01 to 2% by weight, preferably 0.01 to 0.5% by weight. As the lubricant, an inorganic lubricant such as silica, titanium oxide, calcium carbonate, alumina, mica, kaolin and the like, and an organic lubricant containing styrene, silicone and the like as components can be used.

In the polyester film of the present invention, it is necessary to form a polyurethane resin layer on at least one surface of the film to be subjected to a vapor deposition process. As the polyurethane resin layer, a polyurethane resin or a polyurethane polyurea resin can be used. Further, by adding an appropriate amount of a melamine or epoxy crosslinking agent to the polyurethane resin and crosslinking and curing the resin, heat resistance, solvent resistance, and water resistance can be further improved. Also,
Crosslinking and curing can be further promoted by adding an acid catalyst.

The thickness of the polyurethane-based resin layer is set to 0.01 to 0.1 depending on the adhesion to the deposited film and the productivity of the film.
In the range of 5 g / m ² , more preferably 0.03 to 0.1 g
/ M ² . The thickness of the polyurethane resin layer is 0.01
If the thickness is less than g / m ² , the adhesion to the deposited film becomes insufficient,
If the thickness is more than 0.5 g / m ² , the film may cause blocking, which is not preferable.

In the film of the present invention, since the film surface to be subjected to the vapor deposition processing is subjected to an easy adhesion treatment with a polyurethane resin, the adhesion to the vapor deposition film is enhanced, and the gas barrier property of the vapor deposition film is improved. Further, the heat resistance and water resistance of the deposited film are improved.

As the polyurethane resin used in the present invention, for example, a solvent type or self-emulsifying type polyurethane resin or a polyurethane polyurea resin (Japanese Patent Publication No. 3-55302) which does not contain an antifoaming agent is preferable. The addition amount of the melamine-based or epoxy-based crosslinking agent is 3 to 10 parts by weight based on 100 parts by weight of the polyurethane-based resin.
It is preferable that the curing reaction be promoted by adding 0.5 to 1 part by weight of an acid catalyst.

In the present invention, the polyurethane resin layer can be formed by using a known coating method. A method of coating a stretched film with a polyurethane resin can also be used, but a precoat stretching method in which a polyurethane resin is coated before stretching the film and then stretched and heat-set (Japanese Patent Publication No. 3-55302) is used. As a result, the adhesion to the deposited film is further improved, and the productivity of the polyurethane-based resin coated film can be increased. As a method for coating the polyurethane resin, various methods such as an air knife method and a coat bar method can be adopted.

The thickness of the easily adhesive polyester film of the present invention is usually 9 to 50 μm, preferably 10 to 25 μm.
It is.

Examples of the material to be deposited on the base polyester film include oxides such as silicon oxide, aluminum oxide, magnesium oxide and calcium oxide. These may be used alone or as a mixture. Among them, silicon oxide and aluminum oxide are preferred from the viewpoint of gas barrier properties.

As a method of forming a deposited film, a physical vapor deposition method (PVD) such as a vacuum vapor deposition method, an EB vapor deposition method, a sputtering method or an ion plating method, or a chemical vapor deposition method (C
VD) can be used as appropriate.

The transparent vapor-deposited film produced using the biaxially stretched polyester film of the present invention is usually used for laminating with another film such as a biaxially stretched nylon film (ON) or for imparting heat sealability. Polyethylene (PE), polypropylene (CPP), or the like can be used after being laminated. Examples of the configuration of such a laminated film include a deposited film / PE, a deposited film / CPP, a PET / deposited film, a deposited film / ON / CPP, and the like. The lamination method is not particularly limited, but a method such as a dry lamination method or an extrusion lamination method is used.

The transparent vapor-deposited polyester film thus obtained is excellent in gas barrier properties, is excellent in packaging of articles such as coffee, etc., which require fragrance retention, and is excellent in water resistance. Can be used for packaging. In addition, it can be used for applications other than non-food packaging and packaging applications.

[0021]

Next, the present invention will be described specifically with reference to examples. The evaluation methods used in the examples are as follows.

(1) Deformation rate (%) Each of three films cut into a width of 3 mm and a length of 10 mm in the MD and TD directions is set on a thermomechanical analyzer (TMA, SS-10 manufactured by Seiko Electronics Co., Ltd.). , 0.05 N, and the temperature was raised at a temperature rising rate of 15 ° C./min to obtain a TMA curve of the sample film. From the TMA curves of the films in the MD and TD directions, the range of the variation of the deformation rate in each temperature range was shown.

(2) Blocking property After drying the polyurethane resin coating layer, 6 cm × 6 cm
15 pieces of the film cut into a square are laminated with the resin-coated surface facing upward, and heated at 40 ° C. for 24 hours using a hot air drier.
A 0 kg load was applied and left. After cooling to room temperature, the degree of blocking was evaluated as follows. ：: There is no blocking, and there is no catch when peeling. Δ: Slightly caught when peeled, and a little sound was heard. ×: Strongly caught when peeled, damage is seen on the surface of the resin coat layer.

(3) Oxygen permeability (O ₂ TR) (unit: m)
1 / m ² · 24 hr) According to ASTM D-3985, the oxygen permeability of the deposited film at 20 ° C. and 100% RH was measured using an oxygen permeability measuring apparatus (MOCON, OX-TRAN 100 type). Was measured.

(4) Water vapor transmission rate (WVTR) (unit:
g / m ² · 24 hr) Water vapor permeability measuring device (PERMAT, manufactured by MOCON)
Using RAN W1 type), 40
The water vapor permeability was measured under the conditions of 90 ° C. and 90% RH.

Example 1 Using a 6/4 mixed solvent of phenol / tetrachloroethane, PET (containing 0.04% by weight of silica particles) having an intrinsic viscosity of 0.63 measured at 30 ° C. was melted from a T-die at a temperature of 280 ° C. It was extruded and cooled on a drum having a surface temperature of 45 ° C. to obtain an unstretched film having a thickness of 150 μm. A self-emulsifying polyurethane polyurea resin (KU-400SF, manufactured by Dainippon Ink and Chemicals, Inc.) is coated on one side of the obtained unstretched film so that the coating amount of the resin layer after stretch film formation is 0.04 g / m ^2. The solution whose concentration has been adjusted is coated by a coat bar method, and then dried.
After stretching twice, the film was stretched 3.5 times in the transverse direction (TD) at 110 ° C., and then subjected to heat setting at 240 ° C. for 5 seconds to obtain a biaxially stretched film having a thickness of 12 μm. TMA measurement was performed on the obtained stretched film, and the results of measuring the deformation ratio σ (%) in the MD and TD directions of the film were as shown in Table 1. The blocking test results were also good. Next, SiO.sub.2 was added to the obtained stretched film.
x was deposited by a vacuum deposition method to obtain a transparent deposited film.
Table 1 shows the results of measuring the O ₂ TR and WVTR of the obtained deposited film. As shown in Table 1, the obtained vapor-deposited film showed good gas barrier properties.

Example 2 To 100 parts by weight of the polyurethane polyurea resin used in Example 1, 7 parts of a melamine crosslinking agent was added, and the coating amount was 0.05.
A 12 μm-thick biaxially stretched film was obtained in the same manner as in Example 1 except that a solution having a concentration adjusted to g / m ² was coated by a coat bar method, and the heat setting temperature was set to 235 ° C. As in Example 1, the TMA of the stretched film
Table 1 shows the results of the measurement and the evaluation of the performance of the SiOx deposited film.

Example 3 An acid catalyst was added to the polyurethane resin solution used in Example 2 for 0.1 minute.
A biaxially stretched film having a thickness of 12 μm was obtained in the same manner as in Example 2 except that 7 parts by weight was added and coating was performed so that the coating amount was 0.05 g / m ² . Table 1 shows the results of TMA measurement of the stretched film and evaluation of the performance of the SiOx vapor-deposited film in the same manner as in Example 1.

Example 4 A biaxially stretched film having a thickness of 12 μm was obtained in the same manner as in Example 3 except that the amount of the polyurethane resin layer applied was changed to 0.03 g / m ² . As in Example 1, the T of the stretched film
Table 1 shows the results of the MA measurement and the evaluation of the performance of the SiOx deposited film.

Example 5 A biaxially stretched film having a thickness of 12 μm was obtained in the same manner as in Example 3 except that the amount of the polyurethane resin layer applied was 0.1 g / m ² . As in Example 1, TM of the stretched film
Table 1 shows the results of the A measurement and the evaluation of the performance of the SiOx deposited film.

Comparative Example 1 Example 1 except that no polyurethane resin was coated.
In the same manner as in the above, a biaxially stretched film having a thickness of 12 μm was obtained. Table 1 shows the results of TMA measurement of the stretched film and evaluation of the performance of the SiOx vapor-deposited film in the same manner as in Example 1.
It was shown to.

Comparative Example 2 A biaxially stretched film having a thickness of 12 μm was obtained in the same manner as in Example 4 except that the longitudinal stretching temperature was 90 ° C. and the heat setting temperature was 230 ° C. As in Example 1, TM of the stretched film
Table 1 shows the results of the A measurement and the evaluation of the performance of the SiOx deposited film.

[0033] except that the coating amount of Comparative Example 3 resin layer was 0.6 g / m ² Comparative Example 2
In the same manner as in the above, a biaxially stretched film having a thickness of 12 μm was obtained. Table 1 shows the results of TMA measurement of the stretched film and evaluation of the performance of the SiOx vapor-deposited film in the same manner as in Example 1.
It was shown to.

Comparative Example 4 A biaxially stretched film having a thickness of 12 μm was obtained in the same manner as in Comparative Example 2 except that the coating amount of the resin layer was changed to 0.05 g / m ² . As in Example 1, TMA measurement of the stretched film,
Table 1 shows the results of evaluating the performance of the SiOx deposited film.

[0035]

[Table 1]

[0036]

According to the present invention, there is provided a polyester film which is preferably used as a base film for a transparent vapor-deposited polyester film having excellent adhesion to a vapor-deposited film and excellent gas barrier properties.

Claims (2)

[Claims] 1. A film having a load of 5.0 N / m 2 and a vertical and horizontal deformation rate (σ%) of 60 ° C. when heated at a rate of 10 to 20 ° C./min. ~ 140 ° C
, The deformation rate σ ₁ is in the range of −1.8 to 0.7%, and in the temperature range of 140 to 180 ° C., the deformation rate σ ₂ is −
A polyester film for easy adhesion transparent vapor deposition in which a polyurethane resin layer is formed on at least one side of a film having a range of 2.6 to 1.0%. 2. The polyester film according to claim 1, wherein the polyurethane resin layer is crosslinked and cured by a melamine or epoxy crosslinking agent.