JP2567700B2 - Laminated coating cutting method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for cutting a coating of a laminate, and more particularly, to a laminate using an unexposed resin such as an ethylene-vinyl alcohol copolymer as an intermediate layer. The present invention relates to a method of cutting a body in a state where its edges are covered and protected by the inner and outer layer resins.

(Prior Art) Ethylene-vinyl alcohol copolymer is one of the most excellent thermoplastic resin having oxygen barrier property (oxygen permeation resistance), but it is sensitive to humidity, and it is sensitive to high humidity (30 ° C). × 90
% RH), it is known that the oxygen permeability coefficient has a value that is about one digit higher.

Therefore, in the field of packaging materials using ethylene-vinyl alcohol copolymer, a laminated structure in which ethylene-vinyl alcohol copolymer is used as an intermediate layer and moisture-resistant thermoplastic resin such as polyolefin or thermoplastic polyester is used as inner and outer layers. By doing so, the influence of humidity is prevented.

(Problems to be solved by the invention) However, when the laminate is made into the form of a final packaging container, the cut edge of the laminate appears in any part of the container or its precursor molded body, In this part, the ethylene-vinyl alcohol copolymer layer is exposed,
It will be adversely affected by moisture absorption or water absorption. That is,
Although the decrease in oxygen barrier property due to moisture absorption or water absorption has already been pointed out, other problems such as the decrease in adhesive strength due to moisture absorption or water absorption and the accompanying delamination occur, and ethylene-vinyl alcohol copolymer There is a problem such as pollution due to coalescence elution.

A coating protection means for wrapping the cut edge part using a resin tape other than the laminated body is conceivable, but such a means requires labor and steps, and is very suitable for the purpose of providing an inexpensive container by mass production. Absent.

Therefore, an object of the present invention is to provide a method capable of surely protecting the edge of the intermediate layer of a resin in which the exposure of the ethylene-vinyl alcohol copolymer or the like is not desired at the same time as cutting the laminate.

Another object of the present invention is to ensure that the intermediate layer of the resin such as ethylene-vinyl alcohol copolymer whose exposure is not desired does not come into contact with the outside air or the contents, and is reliably covered and protected even at the cut edge portion. It is an object of the present invention to provide a technique for cutting a laminated body in which the above-mentioned drawbacks are eliminated.

(Means for Solving the Problems) According to the present invention, an inner layer and an outer layer are provided, which include an intermediate layer containing an ethylene-vinyl alcohol copolymer or a polyvinylidene chloride resin and inner and outer layers of a polypropylene resin or a polyethylene terephthalate resin. The ratio of the total thickness of the intermediate layer and the thickness of the intermediate layer is in the range of 5: 1 to 80: 1 to form a tray sheet or cup shape, and the outer peripheral portion of the formed flange portion is irradiated with a carbon dioxide laser. The energy density at the position is defined as the energy density on the incident side when the exit side is in a state just before cutting.
Irradiate and cut under the condition that the melt energy of the resin remains at the cut part, which is 1.01 to 2.5 times the through energy density, and the end of the cut edge is an ethylene-vinyl alcohol copolymer layer or polyvinylidene chloride resin layer end. There is provided a method for producing a multi-layer resin container with an edge coated, characterized in that the edge is coated with a polypropylene resin or a polyethylene terephthalate resin.

According to the present invention, an ethylene-vinyl alcohol copolymer or a polyvinylidene chloride resin-containing intermediate layer and a polypropylene resin or polyethylene terephthalate resin inner and outer layers are also provided, and the total thickness of the inner and outer layers and the thickness of the intermediate layer. A coextrusion of a laminate having a ratio of 5: 1 to 80: 1 in the form of a laminated pipe, cutting the extruded pipe to a predetermined size, and stretch-blow forming the formed preform. In the method for producing a multilayer resin container, the laminated pipe is a carbon dioxide gas laser, and the energy density at the incident position is defined as the incident side energy density when the exit side is in a state immediately before cutting. 1.01 to the minimum breakthrough energy density. 2.5 times and irradiated under the condition that the molten phase of the resin remains in the cut part, cut and cut with ethylene- Method characterized by forming the edge of the alkenyl alcohol copolymer layer or a polyvinylidene chloride-based resin layer is covered with a polypropylene resin or polyethylene terephthalate resin edges to each preform is provided.

(Operation) In the present invention, in order to perform the fusion protection of the laminate and the protection of the coating of the edge of the intermediate layer, the laminate is relatively scanned with the carbon dioxide laser beam to perform the cutting. The energy density at (incident position) is 1.01 to 2.5 times the minimum break-through energy density,
In particular, it is necessary to irradiate the beam under the condition of 1.02 to 2.0 times and the molten phase of the resin remains in the cut portion.

In the present specification, the breakthrough energy density has a general meaning, that is, the energy density per area at an incident position where cutting of a laminated body due to irradiation of a beam occurs, and the minimum breakthrough energy. The density refers to the energy density on the incident side when the exit side is in a state immediately before cutting, that is, in a state where a so-called single sheet is left and cut.

This minimum break-through energy density is obtained by changing the energy density of the beam that irradiates the laminated body and observing the beam exit side of the laminated body with a microscope, but it is judged in the state immediately before cutting. Is because if it is in the cut state, it cannot be determined whether or not this is the minimum value of the energy density.

The energy density is represented by energy per area at the incident position, for example, W · sec / cm ² . With the above-mentioned minimum breakthrough energy density, the energy density on the beam exit side of the laminated body is zero.

Conventionally, in the beam cutting of plastics, the focal area of the beam is made as small as possible for the purpose of reducing the heat-affected zone as much as possible, cutting cost as much as possible, and improving the smoothness of the cut. The irradiation is performed at a high energy density, and this energy density reaches 3 to 5 times the minimum breakthrough energy density.

In the present invention, contrary to such conventional technology,
Rather, it was found that when the carbon dioxide laser beam is irradiated with a small energy density close to the minimum breakthrough energy density, the intermediate layer edge is reliably protected by the melt of the inner and outer layer resin. .

FIG. 1 shows a case where the irradiation beam area (energy density) is changed by changing the irradiation position with respect to the beam focus for the laminated body of Example 1 described later using a constant output carbon dioxide laser beam. It is a plot of the relationship between the distance of and the cutting margin (cutting width). In the plot in the figure, the black circles indicate that the edges of the intermediate layer have not been covered, and the white circles indicate that the edges of the intermediate layer have not been covered. Show what is being done. 2 and 3 are cross-sectional views of a photomicrograph (42 times) of a cross section in a direction perpendicular to the cut edge of the laminate, in which 2 is an intermediate layer, 3 is an outer layer, 4 is an inner layer, 5 and 6
Is an adhesive layer, and the edge 7 of the intermediate layer 2 is exposed to the outside in the laminated body shown in FIG. 2 (the black circle in FIG. 1), whereas the laminated body 1 shown in FIG. In (white circle in FIG. 1), it becomes clear that the edge 7 of the intermediate layer 2 has a protective coating layer 8 made of resin as an inner layer or an outer layer.

The results in Figure 1 reveal the following interesting facts. That is, when the irradiation position is close to the beam focus, the energy density is large and the cutting margin (cutting width) is small, but the intermediate layer edge is not protected at all, whereas the irradiation position is Indicates that the cutting margin (cutting width) increases as the energy density deviates from the beam focus and the coating protection of the edge of the intermediate layer is effectively performed.

Further, FIG. 4 shows a coating cut at the edge of the intermediate layer described above for a laminate comprising polypropylene (PP) inner and outer layers and an intermediate layer of ethylene-vinyl alcohol copolymer (EVOH) or vinylidene chloride resin (PVdC). Is a plot of the relationship between the laser output and the distance from the focus position to the irradiation position for those that performed well.When the laser output is large, the energy density is lowered by shifting from the focus, and vice versa. It can be seen that, when the laser output is small, it is effective for cutting the coating to bring the energy density close to the focus so that the energy density is approximately the same as the above case.

Generally, when the laser output is P (W) and the spot diameter of the laser beam is d (cm), the power density F (W / cm ² )
Is the expression Is expressed by, and the time to pass the beam spot diameter is S
(Sec), the relative velocity between the beam spot and the laminate is v (c
m / sec), the energy density Is the expression Will be given in.

In the present invention, the lower limit of the energy density in beam irradiation is set to 1.01 times based on the minimum break through energy density for the following reason. That is, the degree of coating is best when the density of the beam is at the minimum break through energy density, but in this case the cutting of the stack is due to other variable factors such as stack thickness variations and beam output. It may not be possible to reliably perform due to fluctuations, scanning blurring, or the like. By setting the lower limit value to the above value, the cutting performance becomes stable.

Further, in the present invention, the upper limit of the energy density in beam irradiation is set to 2.5 times with respect to the minimum break through energy density for the following reason. That is, the degree of coverage of the intermediate layer at the cut edges of the laminate is good even if the beam irradiation is at a high energy density when the ratio of the intermediate layer thickness / the total thickness of the inner and outer layers is small. In the range of the thickness ratio defined by the invention, when the energy density in beam irradiation exceeds 2.5 times the minimum breakthrough energy density, the intermediate layer is not completely covered.

In the present invention, it is important that the energy density in beam irradiation is within the above range and that the molten phase of the resin remains in the cut portion. That is, the resin of the inner and outer layers absorbs the carbon dioxide laser and strongly generates heat, and the cutting due to this heat is performed by melting and removing (volatilizing) the resin. In the state where the energy density of the beam is higher than a certain reference value, when the resin melts, the vaporization occurs almost at the same time, so the molten phase of the resin is almost absent at the cut portion. If the energy density is less than this standard value, the rate of volatilization of the resin will be lower than the rate of melting of the resin, so that there will be a resin melt phase that is recognizable at the cut portion. The molten phase of this resin flows so as to cover the cut intermediate layer to form a protective coating layer.

The upper limit value of the energy density for leaving the molten phase of the resin in the cut portion can be obtained as follows. First
As already indicated, the figure shows the relationship between the focus position and the cutting margin, and shows the range of the focus position at which good coating cutting is possible. In the figure, the focus position of the minimum breakthrough energy density is the focus position where the coating can be cut + 7 mm
It is slightly larger than + 8mm. Also, from the figure,
The lower limit of the focal position where the coating can be cut is +4 mm. The relationship between the focal position x and the beam spot diameter d is shown in FIG. From Fig. 10, the spot diameter at the +8 mm focal position is 0.58 mm, and the spot diameter at the +4 mm focal position is 0.37 mm.
Is.

The energy density e is given by the above equation (2), and the ratio of energy densities is e ₄ / e ₈ = 0.58 / 0.37 = 1.57 because the laser output and the beam velocity are constant in this case, and 1.57 times is the upper limit value. . The lower limit of the energy density is 1.01 times, which is slightly higher than the minimum breakthrough energy density.

(Preferred Embodiment of the Invention) In FIG. 5 showing an example of the cutting operation in the present invention, the laminated body 1 is placed on the processing table 10. A laser oscillating device 12 connected to a power supply 11 is provided, and a beam generated by the oscillating device 12 is condensed on the laminated body 1 via a beam transmission system 13, a bend mirror 14 and a condenser lens 15. .

Relative scanning between the laser beam and the laminated body can be performed by rotating or moving the processing table of the laminated body or by a method of moving an oscillator or a beam transmission system (including a mirror).

The energy density of the laser beam in the present invention is 1
Focus position adjustment method, 2 beam output adjustment method, 3
It can be set to a predetermined value by a scanning speed adjusting method or a combination thereof. First, the minimum breakthrough energy density (MBTED) in the laminate is specific to the resin type, thickness and layer constitution of the laminate, and can be experimentally obtained for each laminate. For example, for a certain laminated body, a laser beam device with a certain output and a certain carrier system are used to adjust the irradiation position with respect to the focal point to irradiate the laser beam, and the state immediately before the laminated body is completely cut ( The energy density in the state where one skin remains partially at the cut portion of the laminated body) is calculated from the beam output and the beam area, and the energy density to be irradiated is calculated based on this value. In the method 1, the beam area, that is, the diameter d in the formula (2) is changed by changing the irradiation position, and thereby the energy density is set to a predetermined value. In method 2, electrical input to the laser oscillator,
That is, the beam output P is controlled by controlling the current value. In method 3, the energy density is set to a predetermined value by changing the scanning speed v of the laser beam or the laminated body.

In the present invention, as a suitable example of the intermediate layer, ethylene-vinyl alcohol copolymer, for example, the content of 20 to
Examples thereof include 60 mol%, particularly 25 to 55 mol%, and a saponification degree of 96% or more, particularly 99% or more. This ethylene-vinyl alcohol copolymer is particularly excellent in barrier properties against oxygen and carbon dioxide, but it has already been pointed out that it is disadvantageous in that it is sensitive to humidity. The exposure of the edge of the intermediate layer of the ethylene-vinyl alcohol copolymer intermediate layer can be prevented by a simple operation. This ethylene-vinyl alcohol copolymer (EVO
H) should have a molecular weight sufficient to form a film, generally 0.01 dL / g or more, especially 0.05 dL / g, measured at 30 ° C. in a mixed solvent of 85:15 by weight of phenol: water.
It is desirable to have a viscosity of / g or more.

Other suitable examples of the intermediate layer include vinylidene chloride resins, for example, those having a vinylidene chloride unit content of 70 to 99 mol%, particularly 80 to 98 mol%.
As the comonomer contained as a copolymerization component in the vinylidene chloride resin, acrylonitrile, methacrylonitrile, methyl methacrylate, ethyl methacrylate, ethyl acrylate, propyl acrylate, glycidyl methacrylate, glycidyl acrylate, hydroxyethyl acrylate, hydroxypropyl methacrylate, etc. Examples thereof include acrylic monomers and vinyl monomers such as vinyl chloride. The molecular weight of these vinylidene chloride-based resins is generally sufficient to form a film. The vinylidene chloride-based resin is also one that is particularly excellent in barrier properties against gases such as oxygen, water vapor, and carbon dioxide, but this resin is sensitive to heat, light and the like. When this is used as an intermediate layer, by covering the cut edges, these effects can be prevented.

Suitable examples of the inner and outer layers include isotactic polypropylene, ethylene-propylene copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, and blends thereof. .

Other suitable examples of the inner and outer layers include polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate / isophthalate, polyethylene naphthalate, thermoplastic polyesters such as benzoic acid polyester.

These synthetic resins have a water absorption rate measured by ASTM D 570.
Since it has a low water absorbency of 0.5% or less, particularly 0.1% or less, it also has an action of suppressing permeation of water vapor as the resin for the inner and outer layers of the laminate. Further, polypropylene, polyester, polyarylate, and polycarbonate also have an advantage that they have excellent heat resistance.

When the adhesiveness between the intermediate layer resin and the inner and outer layer resins is poor, an adhesive layer is interposed between these layers.

As the adhesive resin (AD) to be interposed between both resin layers,
Carbonyl based on carboxylic acid, carboxylic anhydride, carboxylic acid salt, carboxylic acid amide, carboxylic acid ester, etc. A thermoplastic resin containing a group in the main chain or side chain at a concentration of 1 to 700 milliequivalent (m · eq) / 100 g resin, particularly 10 to 500 meq / 100 g resin can be mentioned. Suitable examples of adhesive resins include ethylene-acrylic acid copolymers, ionically cross-linked olefin copolymers, maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, acrylic acid grafted polyolefins, ethylene-vinyl acetate copolymers, copolymers. Examples thereof include polymerized polyester and copolyamide. The type of adhesive used depends on the type of moisture resistant resin, and acid modified olefin resin is used for polyolefin and styrene resin, and copolyamide and copolyester are used for polyester and polycarbonate. Further, a thermosetting adhesive such as an epoxy type or urethane type may be used.

The laminate used in the present invention may take any form for forming a packaging container such as a film, a sheet or a pipe. The thickness is 1 to 200 μm for film and 2 for sheet
It can have a thickness of 00 to 4000 μm, and a pipe thickness of 200 to 5000 μm. The laminate is generally formed by a coextrusion method, but it can also be produced by a means known per se such as sandwich lamination and dry lamination.

In the laminate used in the present invention, the comparison of the total thickness of the inner and outer layers and the thickness of the intermediate layer is generally conveniently in the range of 5: 1 to 80: 1, when using an adhesive layer, The thickness of the intermediate layer and the thickness of the adhesive layer (total) are 50: 1 to 1: 1:
50, especially 30: 1 to 1:30.

The edge coating cutting method of the present invention is advantageously used in the manufacture of sheet forming containers.

In FIG. 6 showing an example of the sheet forming method, a female die generally designated by 20 and a plug generally designated by 21 are arranged, and a fixture 22 such as a chuck is provided between the female die 20 and the plug 21. The plastic laminated sheet 1 supported by is supplied.

The female die 20 has a cavity (cavity) 23 opened inside, and has a bottom wall surface 24 defining a bottom wall of a container to be molded and a side wall surface 25 defining a container side wall. At the upper end of the side wall surface 25 is located an opening 26 that defines the opening flange of the container. A guide ring 27 is provided above and on the outer peripheral side of the female die 20 integrally with the female die 20. Further, the female die 20 is provided with an exhaust port 29 for maintaining the inside of the cavity under vacuum or reduced pressure. The female die 20 can be moved up and down together with the guide ring 27.

The plug 21 has a front end portion 30 that engages with the sheet and a tapered side wall portion 31 for narrowing the sheet, and is connected to a drive shaft 32. The plug 21 is also provided so as to be movable in the height direction of the side wall portion 31, that is, in the vertical direction in the drawing. plug
An upper die 33 is provided coaxially with 21. The upper die 33 has a cylindrical side wall portion 34.
And a bottom wall portion 35, and the bottom wall portion 35 is provided with an opening portion 36 through which the plug 21 can go in and out. The lower wall 35 is engaged with the female die opening 26 via a sheet to compression-mold the container flange portion, and at the same time, to engage the female die 20 and the upper die 33 with an engaging projection 37. Is provided. The upper die 33 can also move in the vertical direction.
And can be done independently. When the plug 21 is moved to the lowermost position with respect to the upper mold 33, an annular gap is formed between the two, and
The inside of 33 is connected to a pressurized gas mechanism (not shown), and this pressurized gas is supplied to the lower side through this gap.

In this specific example, the laminated sheet 1 is maintained in a molten state. When molding, the female die 20 rises and the plug 21
Is lowered, and the sheet is narrowed down to the surface of the side wall portion 31 of the plug 21 or the periphery thereof. At this time, the guide ring 27
A sufficient molten sheet is drawn in through the. After the narrowing operation is completed, the upper die 33 and the female die 20 are clamped, and the pressurized fluid is blown into the narrowed sheet, or the outside of the sheet is evacuated, Molding is performed into a container having a shape corresponding to the surface of the female mold cavity.

The laminated sheet does not necessarily have to be in a molten state, and may be at a temperature lower than the melting humidity and capable of being stretch-molded. In this case, molecular orientation (uniaxial orientation) due to stretching is given to the side wall portion of the formed container.

The sheet forming operation is not limited to the forming method illustrated in FIG. 6, and it is possible to apply a sheet forming method such as vacuum forming, pressure forming, paired forming, wind pressure forming, drape forming and the like.

The container thus formed is cut at the outer peripheral portion of the flange portion. This cutting can be performed using the apparatus shown in FIG.

The edge coating cutting method of the present invention can also be used to cut a laminated pipe in a method of producing a stretch blow container, which comprises stretching blow molding a laminated pipe, wherein both edges formed by the cutting are: The advantage is that the coating protection of the edges of the intermediate layer takes place simultaneously.

7 and 8 showing an example of a manufacturing process of a coextrusion pipe
In the figure, the multilayer multiple dice 41 include, from the center to the outside, polyolefin (PO) or polyester (PET).
An inner layer passage 42, an adhesive layer passage 43a, an EVOH or PVdC intermediate layer passage 44, an adhesive layer passage 43b, and a PO or PET outer layer passage 45 are arranged. Inner and outer passages 42 and 45
Is a PO or PET extruder (main extruder) 46 and a gear pump 47.
And a branch channel 48. The adhesive passages 43a and 43b are provided in an adhesive extruder (sub-extruder B) 49 equipped with a gear pump, and an EVOH or PVdC intermediate layer passage 44.
Are connected to an EVOH or PVdC extruder (sub-extruder A) 50 with a gear pump, respectively.

The resins supplied into the die from the respective passages are laminated in a predetermined layer structure and extruded through the die orifice 51 into the multilayer pipe 1. The multi-layer pipe is introduced into the sizing homer 53, the diameter of the pipe is adjusted to a predetermined diameter, and then introduced into the cooling tank 54 containing the cooling water,
There the molten pipe is cooled and solidified. In order to also cool the extruded pipe from the inside, in this embodiment an inert gas supply pipe 56 and a cooling water supply pipe 57 extend through the die 41 and along the central axis of the die 41. Then the pipe is taken up from the cooling tank
It is taken out by 58, cut into a predetermined size by a cutting mechanism 59 described in detail later, and becomes a preform or a preform-forming cut pipe.

In FIG. 9 showing the detailed structure of the pipe cutting device,
A laser tube that can move coaxially with the laminated pipe 1 that is cooled and supplied at a speed that is synchronized with the supply speed of the laminated pipe 1.
60 are provided. A rotary optical barrel 61 is provided so as to be rotatable about the axis of the laser barrel 60, and the rotary optical barrel 61 is rotationally driven by a variable speed motor 62 and gears 63a and 63b. In the rotating optical tube 61, the turning mirrors 65a, 65 for guiding the laser beam 65 to the irradiation position 64 of the laminated pipe 1 are provided.
b, 65c and a condenser lens 66 are provided, and the rotating optical tube 6
The laminated pipe 1 is irradiated with a laser beam through the nozzle 67 of 1. It should be understood that moving the focusing lens 66 can change the focus position or spot diameter. Also, through the laser tube 60 and the rotating optical tube 61,
An inert gas such as nitrogen is supplied to the nozzle 67,
By spraying this on the irradiation position, oxidation and combustion of the resin during the cutting operation are prevented. In addition, the support rod is attached to the axial center of the laminated pipe 1 to be supplied.
There is a laser beam receiver 68 for preventing the beam from reaching the opposite side of the laminated pipe at a portion corresponding to the laser beam irradiation position. When the laminated pipe 1 is cut by using this apparatus, the intermediate protective cover layer 8 shown by 8 in FIG. 3 can be formed at both end portions formed by the cutting.

Stretch blow molding from a cut pipe is carried out by means known per se. For example, in the case of the rod stretch forming method, a closed bottom portion is formed at one end of the cutting pipe by a bottoming die, the formed bottomed preform is preheated to the stretching temperature, and then the rod is axially moved by the rod in the blow die. In addition to stretching and stretching in the direction, a fluid is blown in to expand and stretch in the circumferential direction. In the case of the clamp stretch molding method, the cut pipe is preheated to the stretch temperature, then stretched in the axial direction by sandwiching both ends of the pipe with clamps, and expanded and stretched in the circumferential direction by fluid injection in the mold. And

In the present invention, the irradiation of the carbon dioxide laser beam can be performed by a continuous beam or a pulsed beam, and it is needless to say that the irradiation can be controlled intermittently or continuously. The output of carbon dioxide laser is 50 to
The energy density may be selected from the range of 3000 W, particularly 80 to 2000 W so as to achieve the above-mentioned energy density, and the beam diameter (spot diameter) is generally 0.1 to 1.2 mm, particularly 0.2 to 0.9 mm, and the relative scanning speed is also The energy density is determined from the range of 2 to 100 cm / sec, especially 10 to 70 cm / sec so that the above-mentioned energy density can be obtained.

Of the energy density defined by the general formula (2),
The minimum break through energy density naturally changes depending on the type and thickness of resin, but for thin laminated sheets
From 200 (W · sec / cm2), thick pipe (preform)
Up to 3000 (W ・ sec / cm2.

(Effect of the invention) According to the present invention, ethylene-
Vinyl alcohol copolymer or polyvinylidene chloride resin is used, polypropylene resin or polyethylene terephthalate resin is used as the inner and outer layers, and the energy density at the irradiation position of the carbon dioxide gas is 1.01 which is the minimum breakthrough energy density. By irradiating under a condition in which the molten phase of the resin remains at 2.5 times or more and the cut portion remains, it becomes possible to protect the edge of the intermediate layer with the resin for the inner and outer layers simultaneously with the cutting.

For this reason, the intermediate layer of this laminate is prevented from coming into contact with the outside air or other objects, and various inconveniences when using this as a container are eliminated.

(Example) Example 1 The laminated sheet 1 is the same as Example 2 of JP-A-53-21674.
A five-layer sheet composed of PP / deformed PP adhesive / EVOH / deformed PP adhesive / PP molded according to the T-die sheet molding method described in 1., the inner and outer layers are polypropylene (PP), and the middle layer is Is Evar with a weight ratio of 12% and the total thickness is 1 mm.

The rated output of the carbon dioxide laser device used for cutting is
It is 1.2kW and the beam diameter is 18mm. Upon cutting, the laser beam is condensed by a condenser lens with a focal length of 127 mm, and the distance between the lens and the irradiated surface is adjusted,
The energy density of the laser beam on the irradiated surface is adjusted.

The sheet was linearly moved in the cutting direction at a speed of 20 m / min and cut at a laser output of 600 W.

Iodine tincture was applied to the cut end faces, and the state of covering with the inner and outer layer materials of the intermediate layer was examined under the dyeing state by the Eval's iodine reaction.

With a laser power of 600 W, the focus position is +5 mm from the illuminated surface.
The laser beam spot diameter at the time of cutting was 0.425 m from the relationship between the distance x from the focus and the laser beam spot diameter d in FIG.
m.

When cutting was performed with the focal position at a distance of +4 mm from the irradiated surface, it was confirmed from the observation of the stained state of iodine tincture that not only the cutting but also the intermediate layer was covered. Since the spot diameter of the laser beam at this time is 0.375 mm, the energy density obtained from Eq. (2) is about 1.13 times the minimum breakthrough energy density.

Furthermore, when the focal position is cut at a distance of +3 mm from the irradiated surface, the intermediate layer is partially dyed with iodine tincture, so the coating state is bare. Since the spot diameter of the laser beam at this time is 0.325 mm, the energy density is about 1.31 times the minimum breakthrough energy density.

Therefore, in the laminated sheet 1, the coating cut could be performed up to 1.31 times the minimum break through energy density.

Example 2 The laminated sheet 2 is a polyvinylidene chloride resin (PVdC) in which 3 wt% of a vinylidene chloride / methyl acrylate copolymer resin containing 7 wt% of methyl acrylate is mixed with 3 wt% of additives such as a plasticizer and a processing aid. Melt index (melt flow index) with a vinyl acetate content of 28% by weight as the intermediate layer
With ethylene / vinyl acetate copolymer (EVA) of 6g / 10min (190 ℃) as an adhesive and a melting index of 0.5g / 10min (230 ℃)
3 layers 5 layers (PP / EVA / PVdC / EVA / P) with 1mm thickness and 600mm width with ethylene / propylene copolymer resin (PP)
P) Sheets were molded using a co-extrusion sheet molding machine consisting of three extruders, feed block, T-die, chill roll, take-up machine, and take-up machine, and polypropylene (PP) inner and outer layers And the middle layer has a weight ratio of 9%
It is PVdC and has a total thickness of 1 mm.

The carbon dioxide laser device used for cutting has a rated output of 1.
It is 2kW and the beam diameter is 18mm. Upon cutting, the laser beam is condensed by a condenser lens with a focal length of 127 mm,
The energy density of the laser beam on the irradiated surface is adjusted by adjusting the distance between the lens and the irradiated surface.

The sheet was linearly moved in the cutting direction at a speed of 20 m / min and cut at a laser output of 600 W.

The coating state of the intermediate layer was determined by observing the cut surface under a microscope.

With a laser output of 700 W, the focus position is +6 mm from the irradiated surface
When cut at a distance of, the state is just before cutting, and the spot diameter of the laser beam at that time is 0.475 mm. Next, when cutting was performed with the focal position at a distance of +5 mm to +2 mm from the irradiated surface, the cut surface was observed under a microscope, and it was confirmed that the intermediate layer was covered. The spot diameter of the laser beam at this time is 0.425 mm to 0.275 mm, and the energy density of each is 1.12 to 1.73 times the minimum break-through energy density. However,
The closer the focus position is to the surface to be irradiated, that is, the higher the energy density is, the more the intermediate layer protrudes from the inner and outer layers on the cut surface, and the more difficult it is to be covered.

Therefore, the laminated sheet 2 was able to cut the coating at 1.73 times the minimum break through energy density.

Example 3 A laminated pipe was manufactured according to the coextrusion method described in JP-A No. 61-60436, PET / polyamide adhesive / EVOH /
Made of 5 layers of polyamide adhesive / PET, the inner and outer layers are polyethylene terephthalate (PET), the middle layer is Evar with a weight ratio of 5%, and the outer diameter of the pipe is about 30 mm. , The wall thickness is about 3 mm.

The carbon dioxide laser device used for cutting has a rated output of 1.
It is 2kW and the beam diameter is about 18mm. Upon cutting, the laser beam is made incident vertically on the side surface of the pipe by the optical system shown in FIG. The focusing lens has a focal length of 127 mm and focuses the laser beam. By adjusting the distance between the lens and the irradiated surface, the energy density of the laser beam on the irradiated surface is adjusted.

The laser beam optical system moves in the axial direction in synchronization with the axial feed rate of the pipe (12 m / min) while rotating at a speed of 8 m / min. When the cutting is finished, it returns to the axial direction and the next cutting starts. The laser beam is irradiated for each rotation for a time corresponding to one rotation (about 0.8 seconds).

Iodine tincture was applied to the cut end faces, and the state of covering with the inner and outer layer materials of the intermediate layer was examined under the dyeing state by the Eval's iodine reaction.

With a laser output of 1.2 kW, the focus position is +5 mm from the illuminated surface.
When cut at a distance of, the state is just before cutting, and the spot diameter of the laser beam at that time is 0.425 mm. When cutting was performed with the focus position on the irradiated surface, it was confirmed from observation of the stained state of iodine tincture on the cut surface that not only the cutting but also the intermediate layer was covered. Since the spot diameter of the laser beam at this time is 0.26 mm, the energy density is about 1.63 times the minimum breakthrough energy density.

Therefore, in the laminated pipe, the coating cutting was possible at about 1.63 times the minimum breakthrough energy density.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a focal position of a laser beam and a cutting margin (cutting width) and a coating cutting state. FIG. 2 and FIG. 3 are cross-sectional views showing a photomicrograph of a cross section of the laminate. FIG. 4 is a diagram showing the relationship between the laser output and the focal position at which the coating is cut well. 5 and 9 are schematic views of an apparatus for cutting a laminate. FIG. 6 is a schematic view of a laminated sheet forming apparatus. 7 and 8 are schematic views of a laminated pipe forming apparatus. FIG. 10 is a diagram showing the relationship between the distance from the focus and the spot diameter in the laser beam. 1 ... Laminate, 10 ... Processing table, 12 ... Laser oscillator, 15 ... Condenser lens.

Claims (2)

(57) [Claims] 1. An intermediate layer containing an ethylene-vinyl alcohol copolymer or polyvinylidene chloride resin and inner and outer layers of polypropylene resin or polyethylene terephthalate resin, wherein the total thickness of the inner and outer layers and the thickness of the intermediate layer are A laminate sheet having a ratio in the range of 5: 1 to 80: 1 is formed into a tray or cup shape, and the outer peripheral portion of the formed flange portion is cut with a carbon dioxide gas laser from the outlet side at the energy density at the incident position. The minimum break-through energy density defined as the incident side energy density in the case of the state immediately before is 1.01 to 2.5 times and the resin is melted in the cut portion. At the edge, the edge of the ethylene-vinyl alcohol copolymer layer or the polyvinylidene chloride-based resin layer is a polypropylene-based resin or polyethylene. The coated preparation of the multi-layer resinous container edge, characterized in that to coat with terephthalate-based resin. 2. An intermediate layer containing an ethylene-vinyl alcohol copolymer or a polyvinylidene chloride resin and inner and outer layers of a polypropylene resin or a polyethylene terephthalate resin, and the total thickness of the inner and outer layers and the thickness of the intermediate layer. Multi-layer resin consisting of coextruding a laminate having a ratio in the range of 5: 1 to 80: 1 into a laminated pipe, cutting the extruded pipe to a predetermined size, and stretch-blooming the formed preform. In the container manufacturing method,
In the carbon dioxide laser, the energy density at the incident position is 1.01 to 2.5 times the minimum breakthrough energy density defined as the energy density at the incident side when the exit side is in the state immediately before cutting, and the molten phase of the resin at the cut part Is cut by irradiating under the condition that remains, and the edge of the ethylene-vinyl alcohol copolymer layer or the polyvinylidene chloride resin layer is covered with polypropylene resin or polyethylene terephthalate resin at the cutting edge. Is formed on each preform.