JPH02284779A - Method for cutting coating of laminate - Google Patents

Abstract

PURPOSE:To prevent the influence of humidity by cutting the laminate contg. a resin, such as ethylene/vinyl alcohol copolymer, with which the exposing thereof is undesirable, as an intermediate layer in the state of coating and protecting the end edges thereof with inside and outside layer resins. CONSTITUTION:The laminate including the intermediate layer contg. the thermoplastic synthetic resin having no absorption band at 1000 to 900cm<-1> wave number and the inside and outside layers consisting of the thermoplastic synthetic resin having the absorption band at 1000 to 900cm<-1> wave number is formed. A carbon dioxide laser beam is made to scan relatively under the conditions under which the energy density in the irradiation position attains 1.01 to 2.5 times the min. break.through.energy density. The cutting part in which the end edges of the above-mentioned intermediate layer are coated and protected with the resins of the above-mentioned inside and outside layer is formed. The synthetic resin constituting the intermediate layer is the ethylene/ vinyl alcohol copolymer or vinylidene chloride resin and the resin constituting the inside and outside layers is polyolefin or thermoplastic polyester. The laminate having an excellent oxygen barrier property and moisture resistance is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for coating and cutting laminates, and more particularly, the present invention relates to a method for cutting a laminate, and more specifically, for laminates in which the intermediate layer is made of a resin such as ethylene-vinyl alcohol copolymer that is undesirable for exposure. This invention relates to a method for cutting a body with its edges covered and protected by inner and outer resin layers.

(Prior art) Ethylene-vinyl alcohol copolymer is one of the thermoplastic resins with the best oxygen barrier properties (oxygen permeability), but it is sensitive to humidity and cannot be used under high humidity conditions (30°C ×9
It is known that the oxygen permeability coefficient becomes about an order of magnitude larger at 0% RH).

For this reason, in the field of packaging materials that use ethylene-vinyl alcohol copolymers, ethylene-vinyl alcohol copolymers are used as an intermediate layer, and moisture-resistant thermoplastic resins such as polyolefin or thermoplastic polyester are sandwiched between inner and outer layers. This structure prevents the effects of humidity.

(Problem to be Solved by the Invention) However, when this laminate is to be shaped into a final packaging container, the cut edges of the laminate are necessarily present on some part of the container or its precursor. Since the ethylene-vinyl alcohol copolymer layer is exposed in this part,
It will be adversely affected by moisture absorption or water absorption. That is,
As already pointed out, the oxygen barrier property deteriorates due to moisture absorption or water absorption, but there is also a decrease in adhesion strength due to moisture absorption or water absorption, and the resulting separation between layers. There are problems such as contamination due to copolymer elution.

A method of covering and protecting the cut edge using a resin tape other than a laminate is considered, but such a method requires a lot of work and a number of steps, and is completely unsuitable for the purpose of providing inexpensive containers through mass production. do not have.

Accordingly, an object of the present invention is to provide a method that makes it possible to reliably protect the edges of the intermediate layer of resin, where exposure of the ethylene-vinyl alcohol copolymer or the like is undesirable, at the same time as cutting the laminate.

Another object of the present invention is to ensure that an intermediate layer of resin such as ethylene-vinyl alcohol copolymer, which should not be exposed, is protected from exposure to the outside air or contents, and is protected even at the cut edge. The object of the present invention is to provide a technique for cutting a laminate, which eliminates the above-mentioned drawbacks.

(Means for Solving the Problems) According to the present invention, an intermediate layer containing a thermoplastic synthetic resin that does not substantially have an absorption band at wave numbers 10oO to 900 cm-' and an absorption band at wave numbers 1000 to 900 cm-' A laminate including inner and outer layers of thermoplastic synthetic resin having
A method for cutting a laminate, characterized in that relative scanning is performed under conditions of a magnification of 1 to 2.5 times to form a cut portion in which the edges of the intermediate layer are covered and protected by the resin of the inner and outer layers. provided.

In the present invention, it is preferable that the synthetic resin constituting the intermediate layer is an ethylene-vinyl alcohol copolymer or a vinylidene chloride resin, and the synthetic resin constituting the inner and outer layers is polyolefin or thermoplastic polyester.

According to one aspect of the present invention, a laminate sheet comprising an intermediate layer containing an ethylene-vinyl alcohol copolymer or a polyvinylidene chloride resin and inner and outer layers of polyolefin or thermoplastic polyester is formed into the shape of a tray or a cup. Then, the outer periphery of the flange to be formed is irradiated and cut with a carbon dioxide laser under conditions where the energy density at the irradiation position is 1.01 to 2.5 times the minimum break-through energy density, and the cut edge is Provided is a method for producing a multilayer resin container with a coated edge, characterized in that the edge of an ethylene-vinyl alcohol copolymer layer or a polyvinylidene chloride resin layer is coated with polyolefin or thermoplastic polyester.

According to another aspect of the invention, an intermediate layer containing an ethylene-vinyl alcohol copolymer or a polyvinylidene chloride resin and an inner and outer layer of polyolefin or thermoplastic polyester are coextruded in the form of a laminated pipe, and the extruded pipe is obtained. In the manufacturing method of a multilayer resin container, which consists of cutting a preform into a predetermined size and stretch-blow molding the formed preform, a laminated pipe is heated with a carbon dioxide gas laser so that the energy density at the irradiation position is 1. 01 to 2.5 times, and the edge of the ethylene-vinyl alcohol copolymer layer or polyvinylidene chloride resin layer is coated with polyolefin or thermoplastic polyester at the cut edge. A method is provided comprising forming an edge on each preform.

(Function) In the present invention, it has been found that the following two conditions are necessary in order to simultaneously fuse the laminate and cover and protect the edges of the intermediate layer.

The first condition is that the thermoplastic synthetic resin constituting the intermediate layer has virtually no absorption band at wave numbers 1000 to 900 cm-', and the thermoplastic synthetic resin constituting the unidirectional outer layer has an absorption band at wave numbers 1 to 900 cm.
It has an absorption band between 000 and 900 cIll-'. The wave number is a term often used in the field of infrared absorption spectra, and indicates the number of waves (cl') included in a unit length of 1 cm. Wave number 1000 to 900 cm-
The reason why the presence or absence of an absorption band at ' is a problem is that the wavelength of a carbon dioxide laser is 1000 μm, and therefore its wave number corresponds to approximately 943 cm-'. When a carbon dioxide laser is irradiated onto a laminate having the above-mentioned infrared absorption characteristics, the inner and outer layer resins generate a large amount of heat, while the intermediate layer resin generates little heat, and the cut edges of the intermediate layer are covered with the melted material of the inner and outer layer resins. The first condition is satisfied.

Whether the resin used is suitable for the inner and outer layers, or whether the resin used is suitable for the intermediate layer, is determined by measuring the infrared absorption spectrum of the resin. Attached drawings Figures 1, 2A, 2B, 2C, 3 and 4
The figures show polyethylene terephthalate and polypropylene (however, Figure 2A shows polypropylene homopolymer,
Figure 2B shows a propylene/ethylene random copolymer, and Figure 2C shows a propylene/ethylene block polymer. ), wave number 100 for ethylene-vinyl alcohol copolymer and vinylidene chloride resin
It is understood that the infrared absorption spectra in the range from 0 to 900 cm-' are suitable for the inner and outer layers of the laminate, and the latter two for the middle layer of the laminate.

In the present invention, the laminated body and the carbon dioxide laser beam are relatively scanned to perform cutting, and the energy density at the beam irradiation position is 1.01 to 2.5 times the minimum breakthrough energy density; Especially 1.02 to 2.
The second condition is to perform beam irradiation under conditions where the beam is 0 times larger. Herein, the minimum breakthrough
The energy density is the energy density immediately before the laminate is cut, that is, completely cut in the thickness direction, and is expressed as energy per unit area, for example, W-sec/cm'.

Conventionally, in beam cutting of plastics, the focal area of the beam is made as small as possible in order to minimize the heat-affected zone, minimize the cutting allowance, and improve the smoothness of the cut. The irradiation is carried out at a high energy density, and this energy density has a minimum breakthrough
It reaches 3 to 5 times the energy density.

In the present invention, contrary to such conventional technology, when carbon dioxide laser beam irradiation is performed with a low energy density close to the minimum breakthrough energy density, the edges of the intermediate layer are formed by the melted material of the inner and outer layer resins. It has been found that coating protection can be achieved reliably. Figure 5 shows
Distance and cutting distance when the irradiation beam area (energy density) is changed by using a carbon dioxide laser beam with a constant output and changing the irradiation position with respect to the beam focus on the laminate of Example 1, which will be described later. (width of cutting)
In the plots in the figure, black circles indicate cases in which the edge of the intermediate layer is not coated, and white circles indicate cases in which the edge of the intermediate layer is coated. 6 and 7 are cross-sectional views of micrographs (42x magnification) taken in a direction perpendicular to the cut edge of the laminate,
2 is an intermediate layer, 3 is an outer layer, 4 is an inner layer, and 5 and 6 are adhesive layers. In the laminate shown in FIG. 6 (black circle in FIG. 5), the edge 7 of the intermediate layer 2 is exposed to the outside. In contrast, in the laminate 1 in FIG. 7 (white circle in FIG. 5), the intermediate layer 2 is exposed.
The edge 7 is covered with a protective coating layer 8 made of an inner or outer resin layer.
It becomes clear that it has

The results shown in Figure 5 reveal the following interesting facts. In other words, when the irradiation position is close to the beam focus, the energy density is high and the cutting margin (width of the cut) is small, but the edge of the intermediate layer is not protected at all, whereas when the irradiation position is close to the beam focus, It is shown that as the energy density decreases as the beam is deviated from the focus, the cutting allowance (width of cutting) increases and the edge of the intermediate layer is effectively protected.

Furthermore, FIG. 8 shows the above-mentioned cutting of the edge of the intermediate layer for a laminate consisting of inner and outer layers of polypropylene (PP) and an intermediate layer of ethylene-vinyl alcohol copolymer (EVOI+) or vinylidene chloride resin (PVdC). This is a plot of the relationship between the laser output and the distance from the focal point to the irradiation position for cases where the laser output was successful. It can be seen that when the laser output is small, it is effective for cutting the coating to move closer to the focal point and make the energy density similar to that in the above case.

In the present invention, the energy density in beam irradiation is set within the above range based on the minimum breakthrough energy density for the following reason. That is, as described above, the inner and outer layer resins absorb the carbon dioxide laser and generate strong heat, and cutting due to this heat generation is performed by melting and removing (vaporizing) the resin. When the energy density of the beam is higher than the reference value, the resin (
8. When melting occurs, it volatilizes almost simultaneously, so there is almost no melted resin phase in the cut section. However, if the energy density of the beam is below this standard value, the melting rate of the resin is As a result, the volatilization rate of the resin becomes low, and therefore a noticeable molten phase of the resin is present at the cut portion. It is believed that the molten phase of this resin flows to cover the cut intermediate layer to form a protective coating layer. This is why, in the present invention, the upper limit of the energy density of beam irradiation is set to the above value. The degree of coverage is best when the energy density of the beam is at the minimum breakthrough energy density, but in this case the cutting of the laminate is affected by other variables such as laminate thickness variations, beam power variations. , it may not be possible to perform this reliably due to scanning blur or the like. By setting the lower limit to the above value, cutting performance can also be stabilized.

Generally, when the laser output is p (w) and the laser beam spot diameter is d (cm), the power density F
(W/cm') is expressed by the formula, and the time it takes to pass through the beam spot diameter is S
(sec) and the relative velocity between the beam spot and the stacked body is v (cm/5ec), it is given by the energy density.

(Preferred embodiment of the invention) In FIG. 9 showing an example of a cutting operation in the present invention,
The laminate 1 is placed on a processing table 10. A laser oscillation device 12 connected to a power source 11 is provided, and the beam generated by this oscillation device 12 is transmitted through a beam transmission system 13,
The light is focused onto the laminate 1 via the hend mirror 14 and the condensing lens 15.

Relative scanning of the laser beam and the laminated body can be performed by rotating or moving the processing table for the laminated body, or by moving the oscillator or beam transmission system (including mirrors).

The energy density of the laser beam in the present invention can be set to a predetermined value by (1) a method of adjusting the irradiation position with respect to the focal point, (2) a method of adjusting the beam output, (2) a method of adjusting the scanning speed, or a combination thereof. First, the minimum break in the laminate
Through energy density (MBTED) is specific to the type of resin, thickness, and layer configuration of the laminate, and can be determined experimentally for each laminate.

For example, a certain laminate is irradiated with a laser beam using a laser beam device with a certain output and a certain conveyance system, adjusting the irradiation position relative to the focal point, so that the laminate is completely cut ( Partial peeling on the cut part of the laminate.
The energy density in the state in which the irradiation sheet remains is calculated from the beam output and the beam area, and the irradiation energy density is calculated based on this value. In method (2), by changing the irradiation position, the beam area, that is, the formula (2
) change the diameter d, thereby setting the energy density to a predetermined value; In method (2), the beam output P is controlled by controlling the electrical input to the laser oscillation device, that is, the current value. In method (2), the energy density is set to a predetermined value by changing the scanning speed V of the laser beam or the stacked body.

In the present invention, suitable examples of thermoplastic synthetic resins that do not substantially have an absorption band at wave numbers of 100 to 900 cm-' include ethylene-vinyl alcohol copolymers, such as those having a content of 20 to 60 mol%, particularly 25 to 55 mol%. Examples include those having a saponification degree of 96% or more, particularly 99% or more in terms of mol%. Although this ethylene-vinyl alcohol copolymer has particularly excellent barrier properties against oxygen and carbon dioxide gas, it has already been pointed out that its disadvantage is that it is sensitive to humidity. , it is possible to prevent the edges of the ethylene-vinyl alcohol copolymer intermediate layer from being exposed with extremely simple operations. The ethylene-vinyl alcohol copolymer (EVOH) should have a molecular weight sufficient to form a film and is generally measured at 30t in a mixed solvent with a weight ratio of phenonyl:water of 85=15. .01 i/g or more, especially 0.05 dIl
It is desirable to have a viscosity of /g or more.

Another suitable example of the thermoplastic synthetic resin having no absorption band in the wavenumber range is a vinylidene chloride resin, for example, a vinylidene chloride resin containing 70 to 99 mol%, particularly 80 to 99 mol% of vinylidene chloride units.
Examples include those containing 98 to 98 mol%. Comonomers contained as copolymerization components in vinylidene chloride resin include acrylonitrile, methacrylonitrile,
Examples include acrylic 4Ltx forms such as methyl methacrylate, ethyl methacrylate-1, ethyl acrylate, propyl acrylate, glycidyl methacrylate, glycidyl acrylic 1 note, hydroxyethyl acrylate, and hydroxypropyl methacrylate, and vinyl monomers such as vinyl chloride. It will be done. The molecular weight of these vinylidene chloride resins may be sufficient to form a film on the shell. Vinylidene chloride resin is also one of the resins with particularly excellent barrier properties against gases such as oxygen, water vapor, and carbon dioxide, but this resin is sensitive to heat, light, and the like. These effects can be prevented by covering the cut edges when this is used as an intermediate layer.

In addition, there are 55 acrylonitrile and methacrylonitrile units.
High nitrile resins containing from 95 mol % can also be used.

On the other hand, suitable thermoplastic synthetic resins having an absorption band in the wave number range of 1000 to 900 cm-' include polyolefins such as low-1 medium- or high-density polyethylene, isotactic polypropylene, and ethylene-propylene. Polymer, polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer, ethylene-vinyl acetate copolymer, ionically crosslinked olefin copolymer (ionomer), or a blend thereof.

Other suitable examples of synthetic resins exhibiting the above-mentioned infrared absorption properties include thermoplastic polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate/isophthalate, polyethylene naphthalate, and benzoic acid polyester; and terephthalic acid and/or isophthalic acid), polycarbonates, polyamides, fluororesins such as polytetrafluoroethylene and polychlorotrifluoroethylene. Furthermore, polystyrene, styrene-butadiene copolymers, etc. can also be used.

These synthetic resins have a low water absorption rate of 0.5% or less, especially 0.1% or less, as measured by ASTM D, 570, so they can be used as inner and outer layer resins of laminates to prevent the permeation of water vapor. It also has a suppressive effect. Additionally, polypropylene, polyester, polyarylate, and polycarbonate have the advantage of 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) interposed between both resin layers,
Carbonyl (-C-) group based on carboxylic acid, carboxylic acid anhydride, carboxylic acid salt, carboxylic acid amide, carboxylic acid ester, etc. in the main chain or side chain, 1 to 700 millivalent (Ill-eq) 7100 g resin , especially 10
Examples include thermoplastic resins containing a concentration of 500 meq/100 g resin. Suitable examples of adhesive resins are:
Ethylene-acrylic acid copolymer, ionically crosslinked olefin copolymer, maleic anhydride grafted polyethylene, maleic anhydride grafted polypropylene, acrylic acid grafted polyolefin, ethylene-vinyl acetate copolymer, copolymerized polyester, copolymerized polyamide, etc. . The type of adhesive used depends on the type of moisture-resistant resin; acid-modified olefin resins are used for polyolefins and styrene resins, and copolyamides and copolyesters are used for polyesters and polycarbonates. Furthermore,
Thermosetting adhesives such as epoxy and urethane adhesives can also be used.

The laminate used in the present invention can take any form for forming a packaging container, such as a film, sheet, or pipe. The thickness is 1 to 200 μm for a film, 200 to 4000 μm for a sheet, and 200 to 50 μm for a pipe.
It can have a thickness of 00 μm. The laminate is generally formed by coextrusion, but it can also be produced by means known per se, such as Sand-German delamination and tri-lamination.

In the laminate used in the present invention, the total thickness of the inner and outer layers and the thickness of the intermediate layer are generally compared from 2=1 to i oo :
i, particularly preferably in the range of 5:1 to 80:1, and when an adhesive layer is used, the thickness of the intermediate layer and the thickness of the adhesive layer (total) is preferably in the range of 50:1 to 1. :50. In particular, a range of 30:1 to 130 is preferable.

The edge coating cutting method of the present invention is advantageously used in the production of sheet-formed containers.

In FIG. 10 for showing an example of the sheet forming method, a female mold generally designated 20 and a plug generally designated 21 are arranged, and a fixing device such as a chuck is placed between the female mold 20 and the plug 21. A plastic, laminated sheet 1 supported by 22 is supplied.

The female mold 20 has a cavity 23 open therein, a bottom wall surface 24 that defines the bottom wall of the container to be molded, and a side wall surface 25 that defines the side walls of the container. Side wall surface 25
An opening 26 defining the opening flange of the container is provided at the upper end of the container.
is located. Above the female mold 20 and on the outer circumferential side,
A guide ring 27 is provided integrally with 0. Further, this female mold 20 is provided with an exhaust port 29 for maintaining the inside of the cavity at a vacuum or reduced pressure. The female mold 2o can be moved up and down together with the guide ring 27.

The plug 21 has a tip portion 3o that engages with the sheet and a tapered side wall portion 31 for squeezing the sheet.
Connected to 2. 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 figure. An upper die 33 is provided coaxially with the plug 21 . Upper mold 3
3 consists of a cylindrical side wall part 34 and a bottom wall part 35, and the bottom wall part 35 is provided with an opening part 36 through which the plug 21 can go in and out. A retaining protrusion 37 is provided on the lower side of the bottom wall portion 35 to engage with the female mold opening 26 via a sheet to compression mold the container flange portion and to seal the female mold 2o and the upper mold 33. is provided. Although the upper mold 33 is also movable in the vertical direction, its vertical movement can be performed independently of the plug 21. Plug 21 against upper mold 33
When the upper die 33 moves to the lowest position, an annular gap is formed between the two, and the inside of the upper mold 33 is connected to a pressurized gas mechanism (not shown), and this pressurized gas mechanism Gas is supplied to the lower side through this gap.

In this embodiment, the laminate sheet 1 is maintained in a molten state. During molding, the female mold 20 rises and the plug 2
1 descends, and the sheet is squeezed onto the surface of the side wall portion 31 of the plug 21 or around it. At this time, the molten sheet is sufficiently drawn in via the guide ring 27. After the squeezing operation is completed, the upper die 33 and the female die 2o are clamped, and pressurized fluid is blown into the inside of the squeezed sheet, or the outside of the sheet is evacuated. A container having a shape corresponding to the female mold cavity surface is formed.

The laminated sheet does not necessarily have to be in a molten state;
For example, the temperature may be lower than the melting humidity and allow stretch molding. In this case, molecular orientation (-axis orientation) due to stretching is imparted to the side wall of the container to be formed.

The sheet forming operation is not limited to the forming method illustrated in FIG. 10, and for example, sheet forming methods such as vacuum forming, pressure forming, mold forming, air forming, drape forming, etc. can be applied.

The container thus formed is cut at the outer periphery of the flange. This cutting can be done using the apparatus of FIG.

The edge coating cutting method of the present invention can also be used for cutting laminated pipes in a process for manufacturing stretch-blown containers consisting of stretch blow molding the laminated pipes, in which case both edges formed by the cutting include: The advantage is that the edges of the intermediate layer are coated and protected at the same time.

Figures 11 and 1 show an example of the manufacturing process of coextruded pipes.
In Figure 2, the multi-layer die 41 includes polyolefin (PO) or polyester (PO) from the center outward.
PET) Inner layer passage 42, adhesive layer passage 43a, EV
OH or PVdC intermediate layer passage 44, adhesive layer passage 4
3b and a passageway 45 for the po or PET outer layer is arranged. The inner layer and outer layer passages 42 and 45 are made of PO or PE.
It is connected to a T extruder (main extruder) 46 through a gear pump 47 and a branch channel 48. Glue passage 4
3a and 43b are adhesive extruders (
The EVO)l or PVdC intermediate layer passage 44 is connected to the sub-extruder B) 49, and the EVO)l or PVdC extruder with a gear pump (sub-extruder A) 50, respectively.

The resin supplied into the die from each passage is laminated into a predetermined layer configuration and extruded into the shape of the multilayer pipe 1 through the die orifice 51. The multilayer pipe is introduced into a sizing former 53 to adjust the diameter of the pipe to a predetermined diameter, and then introduced into a cooling tank 54 containing cooling water, where the molten pipe is cooled and solidified. In this example, 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 in order to cool the extruded pipe from the inside. The pipe is then taken out from the cooling tank by a take-up mechanism 58 and cut by a cutting mechanism 5, which will be described in detail later.
9, it is cut into a predetermined size and becomes a preform or a cut pipe for forming a preform.

In FIG. 13 showing the detailed structure of the pipe cutting device,
It can move coaxially with the laminated pipe 1 to be cooled and supplied at a speed synchronized with the supply speed of the laminated pipe 1. A laser tube 60 is provided. So that it can rotate around the axis of this laser tube 60? A (space mark) type rotating optical barrel 61 is provided, and this rotating optical barrel 61 is driven by a variable speed motor 62,
It is rotationally driven by gears 63a and 63b. Inside the rotating optical tube 61, there are mirrors 65a and 65b for guiding the laser beam 65 to the irradiation position 64 of the laminated pipe 1.

65c and a condensing lens 66 are provided, and the laminated pipe 1 is irradiated with a laser beam through the nozzle 67 of the rotating optical tube 61. It should be understood that by moving the condenser lens 66, the focal position or spot diameter can be changed. In addition, the laser tube 60 and the rotating optical tube 6
1, an inert gas such as nitrogen is supplied to the nozzle 67, and this is sprayed onto the irradiation position to prevent oxidation and combustion of the resin during the cutting operation. In addition, there is a support rod 67 at the axis of the laminated nozzle 1 to be supplied, and a support rod 67 is provided at the portion corresponding to the laser beam irradiation position to prevent the beam from reaching the opposite side of the laminated nozzle. A laser beam receiver 68 is provided for this purpose. When the laminated pipe 1 is cut using this device, an intermediate protective coating layer 8 shown at 8 in FIG. 7 can be formed on both end edges formed by the cutting.

Stretch blow molding from cut pipes is carried out in a manner known per se. For example, in the case of the Rondo stretch forming method, a closed bottom is formed at one end of the cut pipe by a bottoming mold, and the bottomed preform to be formed is preheated to the stretching temperature, and then the Rondo is formed in a blow mold. It is stretched in the axial direction and expanded and stretched in the circumferential direction by blowing fluid into it. In the case of the clamp stretch forming method, after preheating the cut pipe to the stretching temperature, both ends of the pipe are held between clamps and stretched in the axial direction, and the pipe is expanded and stretched in the circumferential direction by blowing fluid in the mold to form a container. shall be.

In the present invention, the carbon dioxide laser beam irradiation can be performed with a continuous beam or a pulsed beam, and it goes without saying that the irradiation can be controlled either intermittently or continuously. The output of the carbon dioxide laser can be selected from the range of 50 to 3,000 W, especially 80 to 2,000 W, so as to achieve the above-mentioned energy density, and the beam diameter (spot diameter) is generally 0.1 to 1.2 mm, especially 0.
．． From a range of 2 to 0.9 mm and relative scanning speeds of 2 to 100 cm/sec, especially 10 to 70 cm/sec.
The energy density is determined from the range of sec so as to obtain the above-mentioned energy density.

Among the energy densities defined by the above general formula (2), the minimum breakthrough energy density naturally changes depending on the type and thickness of the resin, but the
00 (W-sec/cm”) to thick pipe (
(preform) varies up to 3000 (W-sec/cm2).

(Effects of the Invention) According to the present invention, a resin having substantially no absorption band at wave numbers of 1000 to 900 cm'' is used as the intermediate layer of the laminate, and a resin having an absorption band at wave numbers of 1000 to 900 cm'' is used as the inner and outer layers. Moreover, a carbon dioxide laser beam is used.
By irradiating so that the energy density at the irradiation position is 1.01 to 2.5 times the minimum breakthrough energy density, it is possible to cover and protect the edges of the intermediate layer with the inner and outer resin layers at the same time as cutting. became.

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

(Examples) Example 1 Laminated sheet 1 was prepared according to the T die sheet forming method described in Example 2 of JP-A No. 53-21674.
Molded PP/Deformed PP adhesive/EVOH/Deformed PP
It is a 5-layer sheet consisting of adhesive/PP, the inner and outer layers are polypropylene (PP), and the middle layer has a weight ratio of 12%.
The carbon dioxide laser device used for cutting has a rated output of 1 mm, and the total thickness is 1 mm.
．． The power is 2kW and the beam diameter is 113++I11.

When cutting, use a laser beam with a focal length of 127YQm.
The energy density of the laser beam on the irradiated surface is adjusted by focusing the light with the condensing lens and adjusting the distance between the lens and the irradiated surface.

The sheet was linearly moved in the cutting direction at a speed of 20111/win, and cutting was performed with a laser output of 600W.

Iodine tincture was applied to the cut end face, and the covering state of the inner and outer layer materials of the intermediate layer was examined by staining with EVAL's iodine reaction.

At a laser output of 600W, the focus position is +5 from the irradiated surface.
When cut at a distance of 1111, it is in the state immediately before cutting, and the spot diameter of the laser beam at that time is 0.425 mm from the relationship between the distance Mx from the focal point and the spot diameter d of the laser beam in FIG.

When cutting was carried out with the focal point at a distance of +411II11 from the irradiated surface, it was confirmed from observation of the dyed state of the iodine tincture that not only was the cutting done, but the intermediate layer was covered. The spot diameter of the laser beam at this time is 0.
Since it is 375ma+, the energy density obtained from equation (2) is approximately 1.1 of the minimum breakthrough energy density.
That's three times as much. Furthermore, the focus position is +311I from the irradiated surface.
When cut at a distance of m, the intermediate layer is partially dyed with iodine tincture, so the coverage is just barely there. The spot diameter of the laser beam at this time is 0.325ff1m
Therefore, the energy density is about 1°31 times the minimum breakthrough energy density.

Therefore, in the laminated sheet 1, it was possible to cut the coating up to 1.31 times the minimum break-through energy density.

Example 2 Laminated sheet 2 is made of polyvinylidene chloride resin (PVdC), which is a vinylidene chloride/methyl acrylate copolymer resin containing 7% by weight of methyl acrylate, mixed with 3% by weight of additives such as plasticizers and processing aids. The intermediate layer is an ethylene/vinyl acetate copolymer (EVA) with a vinyl acetate content of 28% by weight and a melt flow index of 6 g710w1n (190°C) as an adhesive, and the melting index is 0.5 g/ l 0 win (230℃) ethylene/
1mm with inner and outer layers made of propylene copolymer resin (pp)
Thickness, 600IQm width, 3 types, 5 layers (PP/EVA/PV
dC/EVA/PP) sheet is formed using a coextrusion sheet forming device consisting of three extruders, a feed block, a T-die, a chill roll, a take-up machine, and a winder, and the inner and outer layers are It is made of polypropylene (PP), has an intermediate layer of PVdC "iC" with a weight ratio of 9%, and has a total thickness of III11.

The carbon dioxide laser device used for cutting has a rated output of 1.
The power is 2kW and the beam diameter is 18mm. For cutting, the laser beam is focused by a condensing lens with a focal length of 111127 mm, and 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.../min, and cutting was performed with a laser output of 600 W.

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

When the laser output cuff is 00W, the focus position is +6 from the irradiated surface.
When cutting at a distance of IDIll, it is in the state just before cutting, and the spot diameter of the laser beam at that time is 0.47
It is 5mm. Next, when cutting was performed with the focus position at a distance of +5 mm to +2 mm from the irradiated surface, microscopic observation of the cut surface confirmed that the intermediate layer was covered. The spot diameter of the laser beam at this time is 0.42
5 mo+ to 0.275+ nm, and the respective energy densities are 1.12 times to 1.73 times the minimum breakthrough energy density. However, as the focal point position approaches the irradiated surface, that is, as the energy density increases, the extent to which the intermediate layer protrudes from the inner and outer layers at the cut surface increases, and it becomes difficult to coat the intermediate layer.

Therefore, in laminated sheet 2, the minimum breakthrough
The coating could be cut at 1.73 times the energy density.

Example 3 A laminated pipe was made into a five-layer structure consisting of PET/polyamide adhesive/EVO)I/polyamide adhesive/PET according to the coextrusion method described in JP-A No. 61-60436. The inner and outer layers are polyethylene terephthalate (PET), the middle layer is Eval with a weight ratio of 5%, the outer diameter of the pipe is about 30 aa+, and the wall thickness is about 3 mm.

The rated output of the carbon dioxide laser used for cutting is 1.
The power is 2kW, and the beam diameter is about 18mm.

For cutting, a laser beam is applied perpendicularly to the side surface of the pipe using the optical system shown in FIG. The focal length of the condenser lens is t2
It is 71 m long and focuses 1/-the 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 rotates at a speed of 8 m/win while increasing the axial feed rate of the pipe (12 m +/+++ in
) to move in the axial direction. Once the cut is complete, it returns to the axial direction and begins the next cut. The laser beam is irradiated for a time corresponding to one rotation (approximately 0.8 seconds) for each cutting.

Iodine tincture was applied to the cut end face, and the covering state of the inner and outer layer materials of the intermediate layer was examined by staining with EVAL's iodine reaction.

With a laser output of 1.2kW, the focal position is + from the irradiated surface.
When cut at a distance of 5 mm, it is in the state just before cutting, and the spot diameter of the laser beam at that time is 0.425.
It is mm. When the focal point was cut at 17 on the irradiated surface, observation of the iodine tincture staining state of the cut surface confirmed that not only the cut but also the intermediate layer was covered. Since the spot diameter of the laser beam at this time is 0.28 mm, the energy density is approximately 1.63 times the minimum breakthrough energy density.

Therefore, in laminated pipes, the minimum breakthrough
The coating could be cut at approximately 1.63 times the energy density.

[Brief explanation of drawings]

Figures 1, 2A, 2B, 1, 2C, 3 and 4 show the infrared absorption spectra of polyethylene terephthalate, polypropylene, ethylene-vinyl alcohol copolymer and vinylidene chloride resin, respectively. show. FIG. 5 is a diagram showing the relationship between the focal position of the laser beam and the cutting margin (width of cutting) and the coating cutting state. FIGS. 6 and 7 are cross-sectional views showing micrographs of cut sections of the laminate. FIG. 8 is a diagram showing the relationship between the laser output and the focal position for good coating cutting. FIG. 9 and FIG. 13 are schematic diagrams of an apparatus for cutting a laminate. FIG. 10 is a schematic diagram of a laminated sheet forming apparatus. FIG. 11 and FIG. 12 are schematic diagrams of a laminated pipe forming apparatus. FIG. 14 is a diagram showing the relationship between the distance from the focal point of the laser beam and the spot diameter. 1... Laminated body, 10... Processing table, 12...
Laser oscillation device, 15... condensing lens. Figure 1 +ooo. Temporary construction (am") 900.0 Fig. 1000゜Awe (cm') Fig. Fig. Fig. Fig. 1Q Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. 1

Claims (5)

[Claims] (1) An intermediate layer containing a thermoplastic synthetic resin that has virtually no absorption band at wave numbers 1000 to 900 cm^-1, and an inner and outer layer made of thermoplastic synthetic resin that has an absorption band at wave numbers 1000 to 900 cm^-1. and a carbon dioxide laser beam, the energy density at the irradiation position is 1.01 of the minimum breakthrough energy density.
A method for covering and cutting a laminate, characterized in that relative scanning is performed under conditions of a magnification of 2.5 times to 2.5 times to form a cut portion in which the edges of the intermediate layer are coated and protected with the resin of the inner and outer layers. (2) The coating of the laminate according to claim 1, wherein the synthetic resin constituting the intermediate layer is an ethylene-vinyl alcohol copolymer or vinylidene chloride resin, and the synthetic resin constituting the inner and outer layers is polyolefin or thermoplastic polyester. Cutting method. (3) The ratio of the total thickness of the inner and outer layers to the thickness of the middle layer is 2:
2. A method of coating and cutting a laminate according to claim 1, wherein the ratio is within the range of 1 to 100:1. (4) Flange formed by molding a laminate sheet into the shape of a tray or cup, which includes an intermediate layer containing an ethylene-vinyl alcohol copolymer or polyvinylidene chloride resin, and inner and outer layers of polyolefin or thermoplastic polyester. The outer periphery of the part is cut by irradiating it with a carbon dioxide laser under conditions where the energy density at the irradiation position is 1.01 to 2.5 times the minimum break-through energy density, and the cut edge is cut with ethylene-vinyl alcohol. A method for producing a multilayer resin container with a coated edge, characterized in that the edge of a polymer layer or polyvinylidene chloride resin layer is coated with polyolefin or thermoplastic polyester. (5) Co-extruding an intermediate layer containing an ethylene-vinyl alcohol copolymer or a polyvinylidene chloride resin and an inner and outer layer of polyolefin or thermoplastic polyester into a laminated pipe, cutting the extruded pipe to a predetermined size, In the manufacturing method of a multilayer resin container, which consists of stretch-blow molding the formed preform, the laminated pipe is heated with a carbon dioxide laser, and the energy density at the irradiation position is 1.01 to 2 of the minimum breakthrough energy density.
．． The edges of the ethylene-vinyl alcohol copolymer layer or polyvinylidene chloride resin layer are coated with polyolefin or thermoplastic polyester. A method characterized by forming a preform.