JP3007337U - Foamed sheet with unevenness display and packaging bag - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a foamed sheet having good recyclability while maintaining physical properties while reducing the thickness and without impairing the design. [Structure] Thickness 0.2 to 2.0 mm (preferably 0.2)
Thickness of 5 to 100 μm (preferably 5 to 30 μm) on one side of the polyolefin resin foam sheet layer
A laminated sheet obtained by laminating the polyolefin-based resin film layer of 1., wherein an unevenness pattern is formed only on the film surface, and an average bubble diameter of the expanded sheet having the unevenness indication is 0. A packaging bag made of a foamed sheet with unevenness display, which is obtained by heat-sealing a foamed sheet having a size of 3 to 1.0 mm.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a laminate of a polyolefin-based resin foam sheet and a polyolefin-based resin film, and more particularly to a laminated foam sheet with an unevenness display and a packaging bag.

[0002]

[Prior art]

 Polyolefin-based resin foam sheets are lightweight, have excellent heat insulation, and are inexpensive, so they are widely used as cushioning buffers for electrical equipment, especially weak electrical equipment.Furthermore, a patterned film is laminated on the foam sheet to improve the design. Even those with improved physical properties are used not only in the packaging field, but also in all fields such as the construction field and automobile field. However, these polyolefin foam sheets have become a cause of environmental problems.In recent years, it has become necessary to take measures such as high performance thinning, incineration processability, biodegradability, and recyclability as substances that cause dust problems. Has been.

[0003]

[Problems to be solved by the device]

 However, the above foamed sheet is colored with ink in order to demonstrate its designability, and when recycled, the recovered resin is colored, and it can only be used for a limited number of purposes, and its recyclability is poor. I have challenges. In addition, the performance requirements for foamed sheets are becoming stricter, and improvements are desired to reduce the physical properties without reducing the thickness, product transportation costs, and the absolute amount of dust.

[0004]

[Means for Solving the Problems]

 The present invention has been made in order to solve the above problems, and an object thereof is to provide a foam sheet having good recyclability while maintaining physical properties, thinning, and not impairing designability. To do.

That is, according to the present invention, there is provided a laminated sheet in which a polyolefin resin film layer having a thickness of 5 to 100 μm is laminated on one side of a polyolefin resin foam sheet layer having a thickness of 0.2 to 2.0 mm. There is provided a foamed sheet with an unevenness display, characterized in that an unevenness pattern is formed only on the surface.

Further, according to the present invention, as a preferred embodiment, there is provided a foamed sheet with unevenness display, characterized in that the unevenness pattern is scattered on the film surface, and the base resin for the foamed sheet layer. Is a polyethylene resin having a density of 0.90 to 0.93 g / cm ³ , MI of 0.1 to 5 g / 10 minutes and a melting point of 115 ° C. or less, and the base resin of the film layer has a density of 0.935 to 0.96 g. / Cm ³ , MI 0.5 to 0.03 g / 10 minutes, and melting point of 125 to 140 ° C. A foamed sheet with a concavo-convex display, which is a linear polyethylene resin, is provided.

Further, according to the present invention, there is provided a foam sheet with a concavo-convex display for packaging, wherein the foam sheet layer has a thickness of 0.2 to 1.0 mm, and the film layer has a thickness of 5 to 30 μm. Further, there is provided a packaging sheet made of a foamed sheet having an unevenness display, characterized in that the foamed sheet layer has an average cell diameter of 0.3 to 1.0 mm and is formed by heat-sealing a foamed sheet.

[0008]

[Action]

 Since the foamed sheet of the present invention has a display portion that is processed by concavo-convex processing regardless of ink, even if the foamed sheet is crushed and melted and recycled, there is no concern that the recycled resin will be colored, and recyclability is improved. It will be excellent. Of course, since no ink is used, it is safe for food packaging. Furthermore, when the surface of the film layer on which the concavo-convex display portion is formed is taken as the front surface, the foamed sheet layer on the back surface is flat without irregularities due to the formation of the concavo-convex display portion, so the buffering property is not lost and a uniform cushioning effect can be expected. It has excellent adhesion to packaging products and, combined with the use of a specific laminated film, enables the foam sheet to be made thinner without deteriorating its physical properties.

Hereinafter, the foamed sheet with unevenness display of the present invention will be described in detail. FIG. 1 is a perspective view showing a foam sheet with an unevenness display according to an embodiment of the present invention. As is clear from FIG. 1, the foamed sheet 1 with a concavo-convex display of the present invention has a polyolefin film layer 3 (thickness of 5 to 100 μm) on one side of a polyolefin resin foamed sheet layer 2 (thickness of 0.2 to 2 mm). Of the laminated sheet, and the uneven pattern 4 is formed only on the surface of the film layer 3.

Next, the foamed sheet of the present invention will be described based on a manufacturing example. In FIG. 2, 5 is a foamed sheet raw roll formed by winding a long polyolefin resin foamed sheet 6, and 7 is a long roll. An original roll of film formed by winding a lengthy polyolefin-based resin film 8. The foamed sheet 6 and the film 8 which are continuously supplied from the rolls 5 and 7 are superposed on each other to form a heat roll 9. And a pressure roll 10 are passed between them to obtain a laminated sheet. The obtained laminated sheet is then passed between the engraving roll 11 and the pressure roll 12 so that the film surface side is in contact with the engraving roll 11 to obtain a long foamed sheet 13 with unevenness display of the present invention. To be

The polyolefin resin constituting the foamed sheet 6 and the film 8 includes high density polyethylene, low density polyethylene, linear low density polyethylene, polypropylene, polybutylene, ethylene-propylene copolymer and ethylene-butene copolymer. Examples thereof include ethylene-propylene-butene copolymer, ethylene-vinyl acetate copolymer, and the like. The polyolefin-based resin forming the foamed sheet 6 and the polyolefin-based resin forming the film 8 are the same series of resins. It is preferable. A preferred embodiment of the polyolefin resin foamed sheet 6 is a polyethylene resin having a density of 0.90 to 0.93 g / cm ³ , MI of 0.1 to 5 g / 10 minutes and a melting point of 115 ° C. or less, and a foaming ratio of 10 to 40. Double, average cell diameter 0.1 to 1.0 mm, closed cell rate 80% or more, particularly preferably density 0.91 to 0.925 g / cm ³ , MI 0.1 to ³ g / 10 minutes, melting point 112 ° C. Examples include polyethylene having the following expansion ratio of 20 to 35 and average cell diameter of 0.3 to 0.8 mm. Further, the foam sheet 6 preferably has a thickness of 0.2 to 1 mm. A preferred embodiment of the polyolefin resin film 8 is a linear polyethylene resin having a density of 0.935 to 0.96 g / cm ³ , an MI of 0.5 to 0.03 g / 10 minutes, and a melting point of 125 to 140 ° C. Those having a size of 5 to 100 μm, particularly preferably 5 to 30 μm can be mentioned. The linear polyethylene-based resin refers to a polyethylene-based resin having a linear structure such as high-density polyethylene and linear low-density polyethylene.

The heat roll 9 located on the film 8 side is provided with a heating means. The heat roll 9 heats the film 8 and the pressure roll 10 presses the film 8 and the foamed sheet 6 together to form a foamed sheet. 6 and the film 8 are heat-sealed to form a laminated sheet, which is sent to the engraving roll 11 provided on the downstream side. The heat roll 9 can be heated by an oil circulation heating method, an induction heating method, a heating wire heating method, an infrared radiation heating method, etc., and the surface temperature is preferably 100 to 200 ° C, particularly preferably 120 to 180 ° C. The heat roll 9 can be made of metal or ceramics, but at least the surface is preferably covered with a sintered body obtained by sintering a fluororesin such as Teflon at 250 to 400 ° C.

The pressure roll 10 located on the side of the foamed sheet 6 may be optionally provided with a heating means, but the surface temperature is preferably 100 ° C. or lower. Examples of means for heating the pressure roll 10 on the foam sheet side include an oil circulation heating method, a dielectric heating method, a heating wire heating method, and an infrared radiation heating method. When the surface temperature of the pressure roll 10 on the foam sheet side is set to 100 ° C. or less and the foam sheet is also heated from the foam sheet side, problems such as secondary surface foaming of only the contact surface of the foam sheet with the roll and surface roughness are suppressed. be able to.

In the method of the present invention, if necessary, a cross-linking agent and / or a cross-linking aid can be applied in advance to the side of the surface of the polyolefin-based resin film 8 that comes into contact with the foaming sheet 6, and in this way. Since the cross-linking agent and the like slightly penetrate into both the film and the foamed sheet to be cross-linked, it is possible to contribute to strengthening the adhesive force and improving the heat resistance of the laminated sheet itself. Examples of the cross-linking agent include di-t-butyl peroxide, t-butyl-cumyl-peroxide, dicumyl peroxide, α, α-bis (t-butylperoxy) -p-diisopropylbenzene, and 2,5-dimethyl. -2,5-di- (t-butylperoxy) -hexyne-3,2,5-dimethyl-2,5-di- (benzoylperoxy) hexane, t-butylperoxyisopropylcarbonate, etc. Is mentioned. Examples of the crosslinking aid include functional vinyl compounds such as divinylbenzene, polyethylene glycol dimethacrylate, triallyl cyanurate and diallyl phthalate, and compounds such as quinonedioxime and bisamide.

The engraving roll 11 located on the laminated sheet film side has irregularities corresponding to the irregularity display formed on the metal roll surface, and the laminated sheet is pressed by the pair of pressure rolls 12. The pressing force at that time is appropriately selected within a range in which the material of the foamed sheet is not broken. Further, a method of heating the laminated sheet film side can also be adopted in order to clearly form the unevenness display on the laminated sheet. As a means for heating the film side, a method of heating the engraving roll 11 or a method of using a heat roll or infrared radiation heating before the laminated sheet is pressed by the engraving roll 11 can be adopted. In addition, when heating such a laminated sheet, it is necessary to sufficiently consider cooling after heating and uneven forming. In addition, in the case of the present invention, the film layer can be sufficiently roughened without heating the engraving roll 11 and the like, and the productivity is also good.

The engraving roll 11 can be formed of the same material as the heat roll 9. The surface material of the pressure roll 12 is preferably made of rubber or paper. It is particularly preferable that the unevenness display on the laminated sheet film layer side formed by the engraving roll is to display figures and characters and / or to be scattered on the sheet in order to have a display function. . Concavo-convex display is not limited to simple lines such as outlines and outlines such as figures and characters, outlines, etc., but it is also possible to adopt satin, grain, knurled patterns, etc. Further, the foamed sheet of the present invention can form the unevenness display on the film layer at the same time when the foamed sheet layer and the film layer are laminated. Further, the foamed sheet of the present invention adopts a foamed sheet having an average cell diameter of 0.3 to 1.0 mm, and by adopting a constitution comprising a specific foamed sheet layer and a film layer, a packaging material can be obtained. Since it is excellent in processability as described above, and particularly good in heat sealability, it becomes good in bag making property. Further, the foamed sheet of the present invention is capable of forming unevenness display only on the film layer while keeping the foamed sheet layer flat by adopting a specific structure. It is possible to easily provide the unevenness provided and also to avoid problems on the front and back. In addition, since the laminated sheet of the foamed sheet layer and the film layer is manufactured in advance and a specific structure that allows a display portion to be attached in a later step is adopted, the foamed sheet layer remains in a good state. Also, it is preferably used as a multi-purpose product in which labeling is appropriately changed as needed without deteriorating the physical properties.

[0017]

【Example】

 Next, the present invention will be described in more detail by way of examples.

Example 1 100 parts of low-density polyethylene (density 0.920 g / cm ³ , MI = 0.3 g / 10 minutes, melting point 110 ° C.) talc 0.5 parts, additives (masterbatch of stearic acid monoglyceride, etc.) ) And 18 parts of a foaming agent were supplied to a 50 mmφ single screw extruder equipped with a 45 mmφ annular die, heated, melted and kneaded, and then extruded from an annular die at the tip of the extruder. At the time of extrusion, the resin temperature measured at the breaker plate portion inserted between the tip of the extruder and the annular die was 108 ° C. As the foaming agent, a mixture of butane and isobutane at a weight ratio of 7: 3 was used, and pressure injection was performed from a supply port provided at a predetermined position of the extruder. The foam extruded from the annular die was cut open to obtain a foam sheet having a thickness of about 0.6 mm and a density of 0.023 g / cm ³ . The obtained foamed sheet and a film of high density polyethylene (density 0.940 g / cm ³ , MI = 0.05 g / 10 min, melting point 130 ° C.) having a thickness of 10 μm were heat bonded using an apparatus shown in FIG. Then, after forming a laminated sheet, a laminated foam sheet was obtained in which PE characters were engraved on the film layer side in a concavo-convex pattern by an engraving roll. The surface temperature of the heat roll 9 was adjusted to 140 ° C., and the engraving roll 11 was set so as not to be heated.

The foamed sheet layer of the obtained laminated foamed sheet had a thickness of 0.5 mm and an average cell diameter of 0. 5 mm, film layer thickness is 10 μm (However, the average cell diameter of the present invention is obtained by averaging the maximum diameter of 100 cells of the foamed sheet layer and the horizontal slice surface as the representative diameter. The film layer is provided with unevenness indication only, and the foamed sheet layer has a flat back surface of the unevenness indication portion and shows no deterioration in cushioning property, and is thin and has good cushioning properties. Met. Furthermore, as a result of forming a buffer packaging bag by bag-making the above laminated foam sheet with an impulse sealer, the heat-sealing property was good.

[0020]

[Effect of device]

 As described above, since the foamed sheet with unevenness display according to claims 1 and 2 has a display portion by unevenness processing without using ink, the recycled resin is colored even if the foamed sheet is crushed / melted and recycled. There is no need to worry about it, and it has excellent recyclability. Of course, since no ink is used, it is safe for food packaging. Further, since the foamed sheet layer on the back surface of the unevenness display portion of the film layer is flat, the cushioning property is not lost, a uniform cushioning effect can be expected, and the adhesiveness with the packaged article is good. Combined with the adoption of the above laminated film, it is possible to make the foamed sheet thinner without deteriorating the physical properties of the foamed sheet.

Since the foam sheet with unevenness display according to claim 3 employs the foam sheet layer and the film layer having a specific density, MI, and melting point, it is particularly easy to form only the film layer in-line after forming the laminated sheet. The effect that the uneven display portion can be formed is added.

Since the foamed sheet with unevenness display according to claim 4 has a particularly thin structure, it is excellent in folding property during packaging and does not show a decrease in strength. The effect of being useful is added.

In the packaging bag made of the unevenness-displaying foam sheet according to the fifth aspect, since the foam has a specific bubble diameter, the heat-sealing property is also excellent, and a favorable packaging bag is formed.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing the structure of a foam sheet with a concave-convex display according to an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram schematically showing an example of manufacturing a foamed sheet with an unevenness display according to the present invention.

[Explanation of symbols]

 1 Foamed Sheet with Concavo-convex Display 2 Foamed Sheet Layer 3 Film Layer 4 Concavo-convex Pattern 5 Foamed Sheet Original Fabric Roll 6 Long Foamed Sheet 7 Film Original Fabric Roll 8 Long Film 9 Heat Roll 10 Pressure Roll 11 Engraving Roll 12 Addition Pressure roll 13 Long foamed sheet with unevenness display

Claims (5)

[Scope of utility model registration request] 1. A laminated sheet comprising a polyolefin resin foam sheet layer having a thickness of 0.2 to 2.0 mm and a polyolefin resin film layer having a thickness of 5 to 100 μm laminated on one side thereof, wherein the film surface has an uneven pattern. A foamed sheet with a concave-convex display, characterized by being formed. 2. The foamed sheet with unevenness display according to claim 1, wherein the unevenness pattern is scattered on the film surface. 3. The base resin of the foamed sheet layer has a density of 0.
90 to 0.93 g / cm ³ , MI 0.1 to 5 g / 10
Of the polyethylene resin having a melting point of 115 ° C. or less, and the base resin of the film layer has a density of 0.935 to 0.9.
The foamed sheet with unevenness display according to claim 1 or 2, which is a linear polyethylene resin having 6 g / cm ³ , MI 0.5 to 0.03 g / 10 minutes and a melting point of 125 to 140 ° C. 4. The foamed sheet layer has a thickness of 0.2 to 1.
0 mm, and the film layer has a thickness of 5 to 30 μm.
The foamed sheet with unevenness display for packaging according to any one of claims 1 to 3, which is m. 5. The average bubble diameter of the foamed sheet layer is 0.3.
A foamed sheet packaging bag with an unevenness display, wherein the foamed sheet according to claim 4 is heat-sealed.