JP2017043406A - Packaging film and packaging bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film to which heat-sealability is imparted by a highly-efficient and highly-safe method, and a packaging bag using the same.SOLUTION: A film is made of a simple substance of a biaxially-oriented polyester layer or a laminate, the surface of which includes a biaxially-oriented polyester layer. The film includes a seal part to which heat sealability is imparted by irradiating at least a partial area of the biaxially-oriented polyester layer with a laser beam to decrease a degree of crystallinity.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a biaxially stretched polyester film imparted with heat sealability and a packaging bag using the same.

  Biaxially stretched polyester films such as a biaxially stretched polyethylene terephthalate film are useful as various packaging materials because they are excellent in strength, heat resistance, dimensional stability, chemical resistance, fragrance retention, and the like. Thus, packaging bags such as flexible pouches formed by heat-sealing such films are expected.

  However, a film having stretchability is poor in heat sealability. Therefore, for example, Patent Document 1 discloses a method of imparting heat sealability by irradiating the surface of a biaxially stretched polyester film with a short pulse to modify the surface.

Japanese Patent Publication No. 4-26339

  The short pulse irradiation method disclosed in Patent Document 1 needs to generate a high output short pulse using a xenon gas lamp or the like in order not to impair the internal orientation of the biaxially stretched polyester film. Such a high-power device has low energy efficiency and it is difficult to ensure safety. For this reason, the approach for providing heat sealability to a biaxially stretched polyester film has not been made for practical use.

  This invention is made | formed in view of such a subject, and it aims at providing the film which provided heat-sealability by the highly efficient and highly safe method, and a packaging bag using the same.

  One aspect of the present invention for solving the above-mentioned problems is a biaxially stretched polyester layer alone or a laminate comprising a biaxially stretched polyester layer on the surface, and is provided in at least a partial region of the biaxially stretched polyester layer. It is a film including a seal portion to which heat sealability is imparted by irradiating a laser beam to lower the crystallinity.

  Moreover, the other situation of this invention is the packaging bag formed by heat-sealing the sealing parts of the above-mentioned film.

  According to the present invention, it is possible to provide a film imparted with heat sealability by a highly efficient and highly safe method and a packaging bag using the film.

The top view and sectional view of the film concerning one embodiment of the present invention A plan view and a cross-sectional view showing a film manufacturing method The top view and sectional drawing of the laminated body film which concern on one Embodiment of this invention Infrared absorption spectrum of biaxially stretched polyester layer The top view of the packaging bag which concerns on one Embodiment of this invention, a side view, and the top view of the film used for manufacture of a packaging bag

(the film)
In FIG. 1, the top view of the film 10 which concerns on one Embodiment, and sectional drawing along the AA 'line | wire are shown. The film 10 is composed of a biaxially stretched polyester layer 30 alone. In a predetermined region 20 of the film 10, a seal portion 40 to which heat sealability is imparted by reducing the crystallinity is formed.

  In FIG. 2, the manufacturing method of the film 10 is shown. In order to form the seal portion 40 in the region 20, the laser beam is continuously irradiated while scanning. In the example shown in FIG. 2, the irradiation spot S of the laser beam is irradiated so as to draw a plurality of parallel linear trajectories at a predetermined interval. As the laser light, it is preferable to use carbon dioxide laser light having an infrared wavelength whose energy is easily absorbed by the biaxially stretched polyester layer 30. Other laser beams can be used as long as the laser beam has an infrared wavelength.

  The region 20 irradiated with the laser light of the biaxially stretched polyester layer 30 is heated to the glass transition temperature or higher by the laser light irradiation, and cooled to the glass transition temperature or lower after the irradiation, thereby reducing the crystallinity. Heat sealability is developed. The region 20 after the scanning irradiation with the laser light only needs to have a reduced degree of crystallinity. As shown in the cross-sectional view of FIG. The microstructures formed in parallel may or may not be formed. Further, the shape of the irradiation spot of the laser beam and the scanning locus can be appropriately selected from arbitrary ones.

  Thus, the method of imparting heat sealability by laser light irradiation can increase energy efficiency compared with the method of imparting heat sealability by irradiating high-power electromagnetic waves with short pulses, It is possible to ensure safety.

(Laminated film)
The laminate film containing biaxially stretched polyester on the surface can be irradiated with laser light to impart heat sealability. In FIG. 3, the top view of the laminated body film 11 and sectional drawing along the BB 'line | wire are shown. The laminate film 11 is a laminate including a biaxially stretched polyester layer 31 and other layers 50 and 32. In a predetermined region 21 of the laminate film 11, a seal portion 40 to which heat sealability is imparted is formed by irradiating the biaxially stretched polyester layer 31 with laser light to lower the crystallinity. As the other layers 50 and 32, for example, an aluminum layer and a biaxially stretched polyester layer can be used, respectively, but the material and the number of layers are not particularly limited.

(Crystallinity)
FIG. 4 shows an infrared absorption spectrum of a biaxially stretched polyethylene terephthalate layer as an example of the biaxially stretched polyester layer. As shown in FIG. 4, the wave number 1300 cm ^-1 or 1400 cm ^-1 or less in the range of infrared absorption spectrum, the peak p of the absorbance is observed. Since this wave number range is a trans-conformational absorption band of CH chain derived from the crystalline substance in the biaxially stretched polyester layer, the absorbance peak p is a measure of crystallinity in the biaxially stretched polyester layer.

Therefore, the absorbance at peak wavenumber in the range of wave number 1300 cm ^-1 or 1400 cm ^-1 The following non-sealing portion not subjected to laser irradiation, the ratio between the absorbance of the sealing portion 40 at the peak wavenumber, the seal portion 40 It can be used as a scale for the expression of heat sealability.

The absorbance at the absorbance peak in the range of wave number 1300 cm ^-1 or 1400 cm ^-1 The following non-sealing portion not subjected to irradiation of the laser light is _{I 1,} when the absorbance of the sealing portion 40 at the peak wavenumber was _{I 2,} I ₂ is preferably 0% or more and 80% or less of I ₁ , that is, 0 ≦ (I ₂ / I ₁ ) × 100 ≦ 80. When I ₂ is greater than 80% of I ₁ , the seal portion 40 has a small amount of decrease in crystallinity and cannot exhibit sufficient seal strength. By setting the peak value of the absorbance of the seal portion 40 within this range, the crystallinity of the seal portion 40 can be sufficiently reduced, and appropriate heat sealability can be imparted to the film 10.

(Packaging bag)
In FIG. 5, the top view of the packaging bag 100 which concerns on one Embodiment, the side view, and the top view of the film 12 used for manufacture of the packaging bag 100 are shown. The packaging bag 100 is a four-side sealed bag manufactured by stacking two films 12 so that regions 22 to be described later face each other and performing a heat sealing process on the peripheral edge. The region 22 indicated by hatching at the peripheral edge of the film 12 is given heat sealability by the above-described method. The film 12 may be a single layer film such as the film 10 or a laminate film such as the film 11.

  The shape of the packaging bag 100 is not limited to the four-sided seal bag, and any shape can be adopted. For example, a film 12 is folded in half, and a three-sided seal bag formed by heat-sealing the combined peripheral edge portion or a film 12 folded in two between the two films 12 is sandwiched, A flexible packaging bag or the like having a self-supporting property formed by sealing the peripheral edge can be used.

  The laminated body film which concerns on Examples 1-7 and Comparative Examples 1 and 2 was created, and the residual rate of the content was measured for the packaging body with the crystallinity, the seal strength, and the laminated body film.

By irradiating carbon dioxide laser light to the peripheral edge of one surface of the laminate in which polyethylene terephthalate (12 μm) / aluminum (7 μm) / polyethylene terephthalate (12 μm) is laminated from the surface, the degree of crystallinity of the polyethylene terephthalate layer on one surface Laminate films according to Examples 1 to 7 and Comparative Examples 1 and 2 having different seal portions were formed. Then, by using the FT-IR (Fourier transform infrared spectrophotometer), polyethylene terephthalate layer of one surface, and the absorbance _{I 1} at the absorbance peak at wavenumber 1300 cm ^-1 or 1400 cm ^-1 or less in the range of non-sealing portion Then, the absorbance I ₂ of the seal portion at the peak wave number was measured, and the ratio of I ₂ to I ₁ was calculated. FT-IR was measured by the ATR method using a single reflection germanium (Ge) prism.

  The heat-sealed process was performed on each laminated film that was heat-sealed by applying heat and a load of 140 ° C. and 0.2 MPa for 2 seconds to each of the produced laminated films, and then subjected to heat-sealing with a tensile tester. The seal strength of was measured.

  In addition, using a laminated film that has been heat-sealed, a packaging bag containing tulobuterol as an example of a content that is easily adsorbed by polyester is prepared, stored at 40 ° C. for 6 months, and then extracted with methanol from the inner polyethylene terephthalate layer. The degree of adsorption of the content was measured by high performance liquid chromatography, and the residual rate of the content was calculated.

  Table 1 shows the above results. In the item of sealability evaluation, “◯” is described as having the required seal strength when the seal strength is 2 N / 15 mm or more, and the required seal when the seal strength is less than 2 N / 15 mm. “×” was described as having no strength.

It was confirmed that the laminate films according to Examples 1 to 7 have sufficient strength. On the other hand, the laminate films according to Comparative Examples 1 and 2 did not exhibit heat sealability. From the above, it was confirmed that an appropriate seal strength was exhibited when I ₂ was 0% or more and 80% or less of I ₁ , and the effect of the present invention was confirmed. When I ₂ was 5% or more of I ₁ , a residual rate of 80% or more could be confirmed even if the contents were easily adsorbed.

  The present invention is useful for a packaging bag manufactured by heat-sealing a film.

10, 12 Film 11 Laminate film 20, 21, 22 Region 30, 31, 32 Biaxially stretched polyester layer 40 Seal part 50 Aluminum layer 100 Packaging bag S Spot p Absorbance peak

One aspect of the present invention for solving the above problems, a laminated body comprising a layer of the layer alone or biaxially oriented polyester biaxially oriented polyester on the surface, a layer of biaxially oriented polyester has a heat-sealable A non-sealed portion having no heat-sealing property, and the sealed portion has a lower crystallinity than the non-sealed portion , and the non-biaxially stretched polyester layer in the range of wave numbers of 1300 cm ^{−1 to} 1400 cm ⁻¹ the absorbance at the absorbance peak of the sealing portion and I _1, the when the absorbance of the sealing portion at the peak wavenumber was I _2, I ₂ is less than 80% 0% more than I _1, it is a film.

Another aspect of the present invention include one or more of the above films, a packaging bag sealing portion with each other are heat sealed.

One aspect of the present invention for solving the above-mentioned problems is a biaxially stretched polyester layer alone or a laminate comprising a biaxially stretched polyester layer on the surface, and the biaxially stretched polyester layer has heat sealability. and the seal portion, and a non-sealing portion having no heat sealing property, the sealing portion has a low degree of crystallinity than non-sealed portion, the non-layer biaxially oriented polyester in the following ranges wavenumber 1300 cm ^-1 or 1400 cm ^-1 When the absorbance at the absorbance peak of the seal portion is I ₁ and the absorbance of the seal portion at the peak wave number is I ₂ , the film has I ₂ of 5 % to 80% of I ₁ .

The laminated body film which concerns on Examples 1-6, the reference example 1, and the comparative examples 1 and 2 was created, and the residual rate of the content was measured for the packaging body with the crystallinity, the sealing strength, and the laminated body film.

By irradiating carbon dioxide laser light to the peripheral edge of one surface of the laminate in which polyethylene terephthalate (12 μm) / aluminum (7 μm) / polyethylene terephthalate (12 μm) is laminated from the surface, the degree of crystallinity of the polyethylene terephthalate layer on one surface Laminate films according to Examples 1 to 6, Reference Example 1 and Comparative Examples 1 and 2 having different seal portions were formed. Then, by using the FT-IR (Fourier transform infrared spectrophotometer), polyethylene terephthalate layer of one surface, and the absorbance _{I 1} at the absorbance peak at wavenumber 1300 cm ^-1 or 1400 cm ^-1 or less in the range of non-sealing portion Then, the absorbance I ₂ of the seal portion at the peak wave number was measured, and the ratio of I ₂ to I ₁ was calculated. FT-IR was measured by the ATR method using a single reflection germanium (Ge) prism.

It was confirmed that the laminate films according to Examples 1 to 6 and Reference Example 1 have sufficient strength. On the other hand, the laminate films according to Comparative Examples 1 and 2 did not exhibit heat sealability. From the above, it was confirmed that an appropriate seal strength was exhibited when I ₂ was 0% or more and 80% or less of I ₁ , and the effect of the present invention was confirmed. When I ₂ was 5% or more of I ₁ , a residual rate of 80% or more could be confirmed even if the contents were easily adsorbed.

One aspect of the present invention for solving the above-mentioned problems is a biaxially stretched polyester layer alone or a laminate comprising a biaxially stretched polyester layer on the surface, and the biaxially stretched polyester layer has heat sealability. A non-sealed portion having no heat-sealing property, and the sealed portion has a lower crystallinity than the non-sealed portion, and the non-biaxially stretched polyester layer in the range of wave numbers of 1300 cm ^{−1 to} 1400 cm ⁻¹ the absorbance at the absorbance peak of the sealing portion and I _1, when the absorbance of the sealing portion at the peak wavenumber was I _2, I ₂ is less than 80% more than 5% of I _1, it is a packaging film.

Another aspect of the present invention is a packaging bag that includes one or more of the above-described packaging films and in which seal portions are heat-sealed.

Claims (3)

  A biaxially stretched polyester layer alone or a laminate including the biaxially stretched polyester layer on the surface, and at least a part of the biaxially stretched polyester layer is irradiated with laser light to lower the crystallinity. The film containing the sealing part which provided the heat-sealability by this. The film includes a non-seal portion to which heat sealability is not imparted,
When the absorbance at the absorbance peak of the non-sealed portion of the biaxially stretched polyester layer in the wave number range of 1300 cm ^{−1 to} 1400 cm ⁻¹ is I _1, and the absorbance of the seal portion at the peak wave number is I ₂ , The film according to claim 1, wherein I ₂ is 0% or more and 80% or less of I ₁ .   The packaging bag formed by heat-sealing the said seal parts of the film of Claim 1 or 2 of 1 or more.

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