JP6079844B1 - Laser processing method to film - Google Patents

Abstract

A processing apparatus capable of imparting heat sealability to a biaxially stretched polyester film by a highly efficient and safe method. A laser processing apparatus includes: a laser oscillator; a film placement unit for placing a film of a biaxially stretched polyester layer alone or a laminate including the layer; a laser output from the laser oscillator; A laser-guided irradiator for guiding a laser beam output from a laser oscillator to a laminated film including a biaxially stretched polyester layer film or a biaxially stretched polyester layer on the surface as a workpiece, and a layer; A film placement section for fixing a single film or a laminate film, and the laser guiding section, or the film placement section and the film placement section, are movable so as to change a laser beam irradiation position on the film. Heat sealability is imparted to the region of the laminate film irradiated with the laser beam. [Selection] Figure 1

Description

  The present invention relates to a laser processing apparatus.

  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 orientation 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. Xenon gas lamps have low energy efficiency, and it is difficult to ensure safety because electromagnetic waves are emitted in a wide range. 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 processing apparatus which can provide heat-sealability to a biaxially stretched polyester film by a highly efficient and highly safe method. To do.

One aspect of the present invention to solve the above problems, the laser machining with a laser-guided portion of inducing the infrared laser oscillator, and the film placing section comprises a roller, an infrared laser beam outputted from an infrared laser oscillator A laser processing method for a film for imparting heat sealability to a film composed of a single layer of a biaxially stretched polyester or a laminate comprising a layer of a biaxially stretched polyester on the surface using an apparatus, A step of placing a stretched polyester layer alone or a film comprising a laminate comprising a biaxially stretched polyester layer on the surface of the film, and guiding the infrared laser beam output from the laser oscillator by the laser guiding portion; Move the laser guide to change the irradiation process of the film and the irradiation position of the infrared laser light on the film. A step of moving, by a roller so as to change the irradiation position of the infrared laser light into the film and the step of performing a winding and feeding of the film, in the area by irradiating an infrared laser beam in a predetermined area of the film It is a laser processing method to a film that imparts heat sealability.

  According to the present invention, it is possible to provide a processing apparatus capable of imparting heat sealability to a biaxially stretched polyester film by a highly efficient and highly safe method.

1 is a conceptual diagram of a laser processing apparatus according to an embodiment of the present invention. The top view and sectional drawing of the film by which laser irradiation which concerns on one Embodiment of this invention was carried out The top view of the film by which laser irradiation which concerns on one Embodiment of this invention was carried out The top view and side view of the packaging bag which concern on one Embodiment of this invention

(Laser processing equipment)
In FIG. 1, the conceptual diagram of the laser processing apparatus 10 which concerns on one Embodiment is shown. The laser processing apparatus 10 includes a laser oscillator 20 and a laminate film 70 including, on the surface, a biaxially stretched polyester single layer film or a biaxially stretched polyester layer, which is a workpiece, the laser beam 60 output from the laser oscillator 20. (Hereinafter referred to as film 70) A laser irradiation unit 30 for irradiating, a film mounting unit 40 for mounting the film 70, and a control unit 50 for controlling the laser oscillator 20, the laser irradiation unit 30 and the film mounting unit 40, respectively. The laser irradiation unit 30 can irradiate the laser beam 60 onto a predetermined position of the film 70 to impart heat sealability.

(Laser oscillator)
A known laser oscillator can be used as the laser oscillator 20. In particular, a carbon dioxide laser including an infrared wavelength at which energy is easily absorbed by the film is suitable. The laser oscillator 20 can adjust and output the output of the laser beam 60, the pulse width, and the like by the control unit 50. The number of laser oscillators 20 is not limited to one, and a plurality of laser oscillators may be used.

(Laser irradiation part)
The laser irradiation unit 30 has a function of adjusting the laser beam 60 output from the laser oscillator 20 to a predetermined spot shape or scanning trajectory and irradiating the film 70. The laser irradiation unit 30 guides the laser beam 60 output from the laser oscillator 20 onto the film 70 and changes the circular spot shape into a predetermined spot shape, and the laser guide unit 31 is replaced with, for example, the film 70. A first drive unit 35 and a second drive unit 36 that irradiate the laser beam 60 to a predetermined position on the film 70 by moving in a plane parallel to the surface are included.

  The laser guiding unit 31 is an optical system that guides laser light, and includes, for example, a first mirror 32, a second mirror 33, a third mirror 34, and a diffractive optical element 37. As shown in FIG. 1, the first mirror 32 is arranged at a predetermined distance from the laser oscillator 20 in the X direction, and the distance can be changed by the first drive unit 35. The second mirror 33 is disposed a predetermined distance away from the first mirror 32 in the Z direction. Since the first mirror 32 and the second mirror 33 are integrally connected, the distance is constant. The third mirror 34 is disposed at a predetermined distance from the second mirror 33 in the Y direction, and the distance can be changed by the second drive unit 36. The diffractive optical element 37 is arranged at a predetermined distance from the third mirror 34 in the Z direction. Since the third mirror 34 and the diffractive optical element 37 are integrally connected, the distance is constant.

  As shown in FIG. 1, by arranging the mirrors at a predetermined angle, the laser beam 60 output from the laser oscillator 20 in the X direction is first reflected by the first mirror 32 and moved in the Z direction. Then, the light is reflected by the second mirror 33 and guided in the Y direction, and then guided again in the Z direction by the third mirror 34 and irradiated onto the diffractive optical element 37. Finally, the laser beam 60 irradiated onto the diffractive optical element 37 changes to an arbitrary spot shape and is irradiated onto the film 70.

  The first drive unit 35 and the second drive unit 36 are each composed of, for example, air cylinders arranged in the XY directions, and the connected laser guiding unit 31 is connected to the XY plane based on a signal from the control unit 50. Move up. As shown in FIG. 1, since the laser guiding unit 31 is connected to the first driving unit 35, the laser guiding unit 31 can be driven in the X direction. Since the third mirror 34 and the diffractive optical element 37 are connected to the second drive unit 36, the third mirror 34 and the diffractive optical element 37 are integrally driven in the Y direction independently of the first mirror 32 and the second mirror 33. When the irradiation position of the laser beam 60 is determined, the control unit 50 can control the first driving unit 35 and the second driving unit 36 to move the laser irradiation unit 30 to the irradiation position on the film 70. .

  Although three mirrors are used for the laser guide unit 31, the number of mirrors is not limited to three and may be appropriately used as long as the laser beam 60 output from the laser oscillator 20 can be scanned on the film 70. Alternatively, a mirror need not be used. For example, a galvano scanner in which a mirror and a motor are combined, or a polygon mirror that scans a laser irradiated on the mirror by rotating a polygonal mirror by the motor may be used. Further, the spot shape of the laser beam 60 diffracted by the diffractive optical element is not limited, and is a straight line having a predetermined length, a dotted line, an alternate long and short dash line, a belt having a predetermined width, a quadrilateral quadrilateral, a wave, and a U-shape. Any shape such as an X shape or an elliptical circumference can be adopted. Further, in order to change the spot shape of the laser beam 60, another optical element such as a lens such as a cylindrical lens may be used instead of the diffractive optical element 37. The first drive unit 35 and the second drive unit 36 can employ a known method such as a combination of a servo motor and a guide rail in addition to the air cylinder.

(Film placement part)
The film placement unit 40 has a function of fixing and transporting the film 70 to the lower part of the laser irradiation unit 30 when performing laser irradiation. The film mounting unit 40 includes, for example, an unwinding roller 41 that sends out the film 70 to the lower part of the laser irradiation unit 30 and a winding roller 42 that sequentially winds up the film 70 after the laser irradiation. The unwinding roller 41 and the winding roller 42 are driven by the control unit 50.

  The film mounting unit 40 is not limited to a roller shape as long as it has a function of fixing and conveying the film 70 when performing laser irradiation. For example, it may be a table-shaped mounting table capable of fixing and transporting a cut sheet film. Such a film mounting unit 40 is driven by a driving unit (not shown) during laser beam irradiation or alternately with irradiation to move the film 70. The movement of the film 70 by the film placement unit 40 may be used for positioning the laser irradiation position, or may be used only for carrying in and out in a processing unit such as a single wafer.

(Method for imparting heat sealability)
FIG. 2 shows a plan view of an example of a biaxially stretched polyester film 70 irradiated with a laser by the laser processing apparatus 10 and a cross-sectional view along the line AA ′. By applying laser light 60 to the peripheral region of the film 70 to reduce the crystallinity of the surface, heat sealability is imparted, and the seal portion 90 is configured. In the illustrated example, a processing mark 80 along the scanning of the laser beam 60 is formed in the region to which the heat sealability is imparted.

  In the example shown in FIG. 2, for example, each time the laser beam 60 is moved in the TD direction by the laser irradiation unit 30 and the movement in the TD direction is performed for one line, the laser beam 60 is set as a spot-like spot. 40 can be combined with moving the film 70 by a predetermined distance in the MD direction for scanning. FIG. 3 shows another example. In the example shown in FIG. 3, the spot shape of the laser beam 60 is set to a linear spot S having a predetermined length that is not parallel to either the TD direction or the MD direction perpendicular to the TD direction, and the film placement unit 40 is stopped. In this state, the laser irradiating unit 30 can irradiate almost the entire region of the seal unit 90 in the same range as the example shown in FIG. In this way, the laser beam 60 is desired to have the heat sealability of the film 70 by appropriately setting and controlling the shape and size of the spot of the laser beam 60 and the movement of the laser irradiation unit 30 and the film mounting unit 40. Although it can scan suitably in an area | region, if the shape of the spot of the laser beam 60 is made into the shape which has an extending | stretching direction like a line segment especially like the example shown in FIG. 3, the direction which is not parallel to an extending | stretching direction Can be scanned efficiently without high-speed and complicated control. Further, by providing the diffractive optical element 37 so as to be rotatable with respect to the direction in which the laser beam 60 passes, the extending direction of the spot shape can be easily changed, and the width of the scanning region can be easily adjusted. Note that the direction of placing the film 70 on the film placement unit 40 and the direction of scanning of the laser light 60 do not necessarily depend on the MD direction and the TD direction.

  The processing mark 80 can be formed by reducing the crystallinity of the film 70 by laser irradiation. Further, the shape of the processing mark 80 varies depending on the output of the laser, the energy density of the irradiation spot, the irradiation speed, and the like. For example, the flatness is lost, and a fine structure having a concave portion or a convex portion may be formed. There are also cases where the reflectance of light changes due to whitening. Further, there may be a case where a processing mark is not formed.

  Thus, the method of imparting heat sealability by laser irradiation can increase the energy efficiency compared to the method of imparting heat sealability by irradiating high-power electromagnetic waves with short pulses, Since light (electromagnetic waves) is not emitted over a wide range, safety can be ensured even if the output is increased. Moreover, according to the laser processing apparatus of this embodiment, since a heavy laser oscillator is not moved, drive cost can be reduced.

  The film 70 may not be a monolayer film of biaxially stretched polyester. Also for various laminated films containing biaxially stretched polyester on the surface, heat sealing properties can be imparted to the surface of the biaxially stretched polyester layer using the laser processing apparatus of the present embodiment.

(Packaging bag)
In FIG. 5, the top view and side view of the packaging bag 100 are shown. The packaging bag 100 forms a storage portion 110 by stacking the two films 70 on which the seal portion 90 is formed by the above-described method so that the surfaces on which the seal portion 90 is formed face each other and performing a heat seal process. It is a four-side seal bag which concerns on an example of the packaging bag manufactured in this way.

  The shape of the packaging bag manufactured using the film 70 is not limited to the four-side sealed bag, and any shape can be adopted. For example, one film is folded in half, and the three-sided sealing bag formed by heat-sealing the combined peripheral part, or the two-folded film is sandwiched between two films, and the peripheral part is sealed. The flexible packaging bag etc. which have the self-supporting property formed are employable.

  The laser processing apparatus which concerns on an Example and a reference example is comprised, The strip | belt-shaped heat seal part of width 14mm is formed in a biaxially stretched polyethylene terephthalate film as an example of a biaxially stretched polyester film, The length of the heat seal part in that case The processing speed in the longitudinal direction (stretching direction of the band) was compared.

(Example)
A laser oscillator with an output of 250 W capable of irradiating a carbon dioxide laser with a wavelength of 10.6 μm, three mirrors, and a ZnSe diffractive optical element capable of irradiating a linear spot shape with a line width of 0.14 mm and a length of 14 mm; The laser processing apparatus which concerns on embodiment was prepared using, and the spot was scanned to the strip | belt-shaped area | region and heat sealing property was provided. The load weight to the 1st drive part and the 2nd drive part was 3 kg. The processing speed was 50 m / min. Further, the laser beam was not leaked to other than the desired location.

(Reference example)
A laser oscillator with an output of 30 W capable of irradiating a carbon dioxide gas laser with a wavelength of 10.6 μm was moved, and a circular spot with a diameter of 0.3 mm was scanned in a band-like region to impart heat sealability. The load on the drive unit for moving the laser oscillator was 55 kg. The processing speed was 0.5 m / min. Further, the laser beam was not leaked to other than the desired location.

  From the above results, it was confirmed that the heat sealability could be safely imparted to the film by laser light. By providing a laser irradiation unit that guides the laser beam from the laser oscillator to a specified position and using a diffractive optical element that can change the spot shape, there is no need to move a heavy laser oscillator, and the driving load It was confirmed that the safety can be further improved by greatly reducing the machining speed and the processing speed can be dramatically improved.

  The present invention is useful for a laser processing apparatus for a film or the like.

DESCRIPTION OF SYMBOLS 10 Laser processing apparatus 20 Laser oscillator 30 Laser irradiation part 31 Laser guidance part 32 1st mirror 33 2nd mirror 34 3rd mirror 35 1st drive part 36 2nd drive part 37 Diffraction optical element 40 Film mounting Part 41 Unwinding roller 42 Winding roller 50 Control part 60 Laser 70 Film 80 Processing trace 90 Seal part 100 Packaging bag 110 Storage part

Claims (5)

And the infrared laser oscillator using a film mounting unit includes a roller, a laser machining apparatus and a laser-guided portion to induce an infrared laser beam emitted from the infrared laser oscillator, biaxial layers alone of oriented polyester or A laser processing method for a film for imparting heat sealability to a film comprising a laminate comprising a biaxially stretched polyester layer on the surface,
Placing the film on the film placement section ;
Irradiating the infrared laser beam output from the laser oscillator by irradiating the film with the laser guiding unit ;
A step of moving the laser guiding portion so as to change the irradiation position of the infrared laser beam to the previous SL film,
By the roller so as to change the irradiation position of the infrared laser beam to the previous SL film and a step for retracting and feeding of the film,
A laser processing method for a film, in which a predetermined region of the film is irradiated with the infrared laser light to impart heat sealability to the region. The laser processing method for a film according to claim 1, wherein the laser guiding unit includes an optical element that shapes the spot shape of the infrared laser light into a predetermined shape. The predetermined shape is a line segment shape having a predetermined length;
The laser processing method to a film according to claim 2, wherein the film is irradiated with the infrared laser light by scanning in a direction different from the extending direction of the spot-shaped line segment shape. The laser processing method for a film according to claim 3, wherein the film is irradiated with the infrared laser light by scanning in a direction not orthogonal to the stretching direction of the spot-shaped line segment shape. The laser guide unit is rotatably provided with the optical element,
The laser processing method for a film according to claim 4, wherein the stretching direction of the spot-shaped line segment shape can be changed by rotating the optical element.

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