JP2002370297A - Heat-shrinkable cellular cushioning sheet and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-shrinkable cellular cushioning sheet having recyclability, excellent in continuous productivity and comprising a resin such as a non-crosslinked polyolefin or the like, and a method for manufacturing the same. SOLUTION: The heat-shrinkable cellular cushioning sheet comprises an embossed film having a large number of projections formed thereto, a planar base film laminated to the surface having no projections of the embossed film to form projected closed cells and the non-crosslinked heat-shrinkable film laminated to the embossed film or the base film. The method for manufacturing the heat-shrinkable cellular cushioning sheet is also disclosed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-shrinkable foamed buffer sheet in which a foamed cushioning sheet and a non-crosslinked heat-shrinkable film are bonded by heat fusion, and a method for producing the same.

[0002]

2. Description of the Related Art Japanese Utility Model Laid-Open Publication No. 57-16333 discloses a plastic film having substantially no irregularities on the flat side or on both sides of a plastic film having many hollow convex protrusions on one side. , Called flat film)
Are laminated, and at least one of the planes is a heat-shrinkable film, so that the heat-shrinkable film is composed of a plastic laminate material having a large number of convex protrusions forming independent air chambers. A cushioning material is disclosed.

Japanese Utility Model Application Laid-Open No. 62-75926 discloses a heat shrink provided with convex protrusions which are stretched in at least one direction and have a large number of independent air chambers having a heat shrinkage of 10 to 90%. A shock absorbing material is disclosed.

Japanese Patent Application Laid-Open No. 63-80 discloses a polyolefin hollow sheet having a multiplicity of hollow sealed chambers in which a flat polyolefin film is spread on the open side of a polyolefin sheet forming a plurality of convex portions. In addition, there is disclosed a shrink foam cushioning material characterized in that a heat-shrinkable polyolefin film is integrally spread on the polyolefin hollow sheet.

JP-A-1-87243 discloses a heat-shrinkable cellular sheet characterized in that a heat-shrinkable polyolefin film and a cellular sheet are laminated via an adhesive.

Japanese Unexamined Patent Publication No. 6-297618 discloses a heat-shrinkable bubble characterized in that a heat-shrinkable film as a cross-linked film is bonded to one surface of a bubble buffer made of a non-crosslinked resin. A cushioning material is disclosed.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-shrinkable bubble buffer sheet made of a resin such as a non-crosslinked polyolefin having recyclability, excellent continuous productivity, and a method for producing the same. I do.

[0008]

The heat-shrinkable bubble-absorbing sheet of the present invention is formed by laminating an embossed film having a large number of projections formed thereon and a surface of the embossed film on which the projections are not formed. It is characterized by comprising a planar base film forming convex closed cells, and a non-crosslinked heat-shrinkable film bonded to the embossed film or the base film.

The heat-shrinkable bubble-absorbing sheet of the present invention comprises an embossed film having a large number of convex projections, and a convex closed cell formed by adhering to the surface of the embossed film on which the convex projections are not formed. A planar base film to be formed, a top film on a plane bonded to the top surface of the convex protrusion of the embossed film, and a non-crosslinked heat-shrinkable film bonded to the top film or the base film. And characterized in that:

The method for producing a heat-shrinkable bubble-absorbing sheet according to the present invention is characterized in that a plastic film is wound around an embossing roll having a large number of concave portions on its peripheral surface to form convex protrusions, and the emboss film having convex protrusions is formed. Almost simultaneously with winding the base film extruded in a molten state on the embossing roll, a non-crosslinked heat-shrinkable film is further wound on the embossing roll so as to contact the base film. It is characterized by wearing.

Preferably, the method for producing a heat-shrinkable bubble-absorbing sheet of the present invention comprises a bubble-absorbing film having convex closed cells in which an embossed film having a large number of convex protrusions and a planar base film are bonded. At the same time as winding the top film extruded in a molten state on the top surface of the convex protrusions of the embossed film of the sheet on a pressure roll, a non-crosslinked heat-shrinkable film is brought into contact with the top film almost simultaneously. It is further characterized by being wound and thermally fused on a pressure roll.

[0012] At least one of the base film and the top film is made of polyethylene 100.
An unsaturated carboxylic acid-grafted polyethylene obtained by grafting or reacting 0.01 to 5 parts by weight of an unsaturated carboxylic acid to part by weight can be used.

The heat-shrinkable bubble-absorbing sheet of the present invention comprises a non-crosslinked embossed film, base film and heat-shrinkable film and / or a non-crosslinked embossed film, base film, top film and heat-shrinkable film. Because it is composed, it is environmentally friendly, can be melted by heat, has excellent recoverability, can be recycled, and has excellent recyclability. The heat-shrinkable bubble buffer sheet of the present invention,
It is preferable to be composed of an embossed film, a base film, a top film and a heat-shrinkable film that do not contain halogen. In particular, it is preferable that the heat-shrinkable bubble buffer sheet of the present invention is composed of an embossed film, a base film, a top film, and a heat-shrinkable film made of a polyolefin containing no halogen.

In the heat-shrinkable bubble-absorbing sheet of the present invention, the base film and / or the top film to be bonded to the non-crosslinked heat-shrinkable film may contain 0.01 to 5 parts by weight of unsaturated carboxylic acid per 100 parts by weight of polyolefin. By using a film containing or consisting of an unsaturated carboxylic acid-grafted polyolefin grafted or reacted with an acid, excellent adhesion to a base film and / or a top film bonded to a non-crosslinked heat-shrinkable film This is preferable because it can be easily and continuously produced.

Examples of unsaturated carboxylic acids include maleic acid, itaconic acid, citraconic acid and anhydrides thereof.
Monoesters and the like can be used. The unsaturated carboxylic acid-grafted polyolefin can be obtained by grafting an unsaturated carboxylic acid to a polyolefin using a known method. In particular, as the unsaturated carboxylic acids, maleic acid, anhydrides and monoesters thereof can be used.

As the non-crosslinked heat-shrinkable film, a monolayer film including a uniaxially stretched film such as a non-crosslinked polyolefin, polyamide, polyester and the like and a biaxially stretched film can be used. As the non-crosslinked heat-shrinkable film, a multi-layer laminated film including a non-crosslinked uniaxially stretched film such as polyolefin, polyamide and polyester, and a biaxially stretched film can be used. As the non-crosslinked heat-shrinkable film, a uniaxially stretched film and a biaxially stretched film of a non-crosslinked polyolefin are preferable. As the non-crosslinked heat-shrinkable film, a uniaxially stretched film and / or a biaxially stretched film of uncrosslinked polypropylene are preferable.

As the polyolefin, any resin can be used as long as it is a non-crosslinked polyolefin. Further, it is preferable that a halogen such as chlorine or fluorine is not contained in the main chain or side chain of the polymer. Examples of the polyolefin include low-density polyethylene, high-density polyethylene, ethylene or a polymer mainly composed of ethylene such as a (co) polymer of ethylene and an α-olefin having 3 to 10 carbon atoms, and an ethylene-based copolymer; A homopolymer, a polymer mainly composed of propylene such as a (co) polymer of propylene and an α-olefin having 2 to 10 carbon atoms excluding propylene; and a main chain or a side chain such as poly-4-methylpentene-1 Polymers containing no halogen such as chlorine and bromine can be used, and two or more of these polymers can be used as a mixture. Examples of the ethylene-based copolymer include ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-methacrylate copolymer,
Ethylene copolymers such as ethylene / acrylic acid copolymer, ethylene / methacrylic acid copolymer, and ethylene / propylene rubber are exemplified. As the polyolefin, a polymer capable of forming a film can be used.

As the polyamide, aliphatic polyamides such as nylon 6, nylon 66, nylon 11, and nylon 12 can be used. As the polyester, polyethylene terephthalate, polybutylene terephthalate, or the like can be used.

The embossed film, base film, top film and heat-shrinkable film constituting the heat-shrinkable bubble-absorbing sheet of the present invention contain a polymer mainly composed of uncrosslinked ethylene and / or uncrosslinked propylene. By using the main polymer, it is environmentally friendly, can be melted by heat, has excellent recoverability, can be recycled, and has excellent recyclability. In particular, the embossed film, base film and top film constituting the heat-shrinkable bubble buffer sheet of the present invention use a polymer mainly composed of non-crosslinked ethylene, and the heat-shrinkable film mainly composed of non-crosslinked propylene. By using a polymer that is environmentally friendly, heat melting is possible and excellent in recoverability,
Recyclable, excellent in recyclability, and excellent in productivity.

The film constituting the heat-shrinkable bubble buffer sheet can be colored using a coloring component containing no halogen. Monoazo yellow, disazo yellow, and the like can be used as a coloring component containing no halogen, and a coloring masterbatch, TET 2KA567 YEL-FD manufactured by Toyo Ink Mfg. Co., Ltd. containing these can be used.

The non-crosslinked heat-shrinkable film and polyolefin may be used in accordance with the intended use, such as non-halogen higher fatty acids, higher aliphatic amides, metal soaps, lubricants such as glycerin esters, anti-blocking agents, phenolic and phosphorus based materials. Antioxidants such as benzophenone, benzotriazole, and HALS; inorganic and organic fillers such as talc, diatomaceous earth, and mica; antistatic agents; and surfactants.

The polyolefin used in the present invention is mixed and kneaded with various kneaders such as a Banbury mixer, a roll mixer, a kneader, a high-speed rotary mixer and an extruder, preferably a single screw or twin screw extruder. Can be obtained. Also, kneading can be performed during film inflation or T-die molding. Also,
It is also possible to mix by solution blending using a suitable good solvent.

In the present invention, the bubble buffer sheet is a bubble buffer sheet having a large number of convex closed cells in which a large number of embossed embossed films and a planar base film are laminated. An embossed film on which a number of convex protrusions are formed is bonded to a flat base film, and air bubbles are formed inside the convex protrusions of the embossed film. May be a three-layer structure in which top films are laminated. The embossed film does not allow air to escape from the air bubbles after forming a large number of air bubbles by bonding the embossed film to the base film by a method such as heat fusion.

The heat-shrinkable bubble buffer sheet of the present invention preferably has at least one heat-shrinkable layer, particularly preferably one heat-shrinkable layer.

The embossed film, base film and top film used in the heat-shrinkable bubble-absorbing sheet of the present invention preferably have a density of 0.915 (g / cm ³ ).
0.950 (g / cm ³ ), more preferably 0.918 (g / cm ³ ) to 0.945 (g / cm ³ )
, Particularly preferably 0.920 (g / cm ³ ) to
It is set in the range of 0.940 (g / cm ³ ). Setting in such a range is preferable because there is no tackiness, the film has stiffness, and it is possible to withstand the stress during heat shrinkage.

The heat-shrinkable bubble buffer sheet of the present invention preferably has a shrinkage ratio of 4 to 35%, more preferably 5 to 35%.
32%, more preferably 6-30%, more preferably 7-28%, particularly preferably 8-2.
In the range of 5%, it is preferable that no air escape from the bubble portion occurs.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. The present invention is not limited only to these embodiments.

FIG. 1 is an explanatory view of a heat-shrinkable bubble buffer sheet (heat-shrinkable bubble buffer sheet) 1 which is an example of the present invention. The heat-shrinkable bubble buffer sheet 1 includes an embossed film 22, a base film 24, and a heat-shrinkable film 25.
Are laminated and attached to each other, and have a bubble portion 3. FIG. 2 is a cross-sectional view of the heat-shrinkable bubble buffer sheet 1.

The embossed film 22 has a large number of protrusions or embosses 21. The protrusions 21 preferably have a flat top as shown in FIG. In FIG. 1, the projections 21 are regularly arranged in a lattice, but the arrangement of the projections 21 is not limited. The embossed film 22 is
Has a surface on which the protrusions 21 protrude and a surface on which the protrusions 21 do not protrude, and the base film 24 is bonded to the surface on which the protrusions 21 do not protrude. As a result, the projections 21 form the air bubbles 3 together with the base film 24, and the air bubbles have a buffering action. The base film 24 and the heat shrinkable film 25 are directly bonded.

FIG. 3 is an explanatory view of a heat-shrinkable bubble buffer sheet (heat-shrinkable bubble buffer sheet) 7 which is another example of the present invention. In the heat-shrinkable bubble buffer sheet 7, the heat-shrinkable film 26, the top film 27, the embossed film 22, and the base film 24 are laminated in this order and bonded. In this embodiment, the top film 27 is attached to the surface of the embossed film 22 on the side where the projections 21 protrude. That is, the top film 27 and the base film 24 are bonded together with the embossed film 22 interposed therebetween. In the heat-shrinkable bubble buffer sheet 7, the bubble portions 3 formed by the projections 21 and the base film 24 not only have a buffering action, but are also sandwiched between the embossed film 22 and the top film 27.
The space outside the projection 21 also has a buffering action. FIG. 4 is a cross-sectional view of the heat-shrinkable bubble buffer sheet 7.

The thickness of the embossed film is preferably such that the thickness of the convex closed cell portion (emboss) is 10 μm to 8 μm.
0 μm, more preferably 18 μm to 60 μm, particularly preferably 20 μm to 55 μm. The film thickness other than the embossed portion is preferably 15 μm to 2 μm.
00 μm, more preferably 18 μm to 150 μm, particularly preferably 20 μm to 130 μm. The film thickness of the base film is usually preferably 15 μm to 150 μm, more preferably 18 μm to
100 μm, particularly preferably in the range of 20 μm to 80 μm.

The embossed film 22 and the base film 2
As for No. 4, one molded by either the inflation method or the T-die method can be used. In particular, when a base film formed by the T-die method is used, when a heat-shrinkable film is bonded to a base film or the like, the shrinkage of the heat-shrinkable film can be suppressed, which greatly affects the heat-shrinkable film. Is preferred because of the small amount.

The top film 27 is not particularly limited as long as it is a film or sheet that can be heat-fused while being pressed against the embossed film 22. The thickness can be appropriately selected depending on the material to be used.
μm, further 12 μm to 90 μm, especially 15 μm to 80 μm
The range of μm is preferred. The top film 27 may be formed by either the inflation method or the T-die method. In particular, top film 2
7 is the case where the one molded by the T-die method is used,
It is preferable that the heat-shrinkable film is adhered to the embossed film 22 or the like because shrinkage of the heat-shrinkable film can be suppressed and the heat-shrinkable film is not greatly affected.

The bubble buffer sheet (bubble buffer sheet)
Each of the embossed film 22, the top film 23, the top film 27, and the base film 24 may use not only a single-layer film but also a multilayer film of two or more layers. However, it is a film that does not allow air to escape from the emboss after forming a large number of embosses.

The shape of the emboss is mainly a cylinder, but it may be a polygonal prism such as a triangular prism, a prism, a pentagonal prism or a hexagonal prism, a cone, or the like.
Triangular pyramids, pyramids, polygonal pyramids such as pentagonal and hexagonal pyramids, truncated cones, triangular pyramids, truncated pyramids, truncated pyramids such as pentagonal and hexagonal pyramids, hemispheres, ovals, spheroids, etc. Can be. Further, a plurality of these shapes may be combined.

The height of the emboss is preferably in the range of 1 to ²⁰ mm and the bottom area of 0.1 to 1.5 cm ² . Further, it is preferable that the embosses are arranged on the entire surface or almost the entire surface of the embossed film 22 at intervals of 0.5 to 20 mm.

Preferred embodiments of the method for producing the heat-shrinkable bubble buffer sheet (heat-shrinkable bubble buffer sheet) include:
(1) The emboss 21 is formed on the embossed film 22, and (2) simultaneously with or after the formation of the emboss 21,
The base film 24 and the heat-shrinkable film 25 are wound around the embossed film 22, and preferably, the base film 24 and the heat-shrinkable film 2
5 is wound substantially simultaneously, and a base film 24 and a heat-shrinkable film 25, which are preferably extruded in a molten state on the embossed film 22, are wound, and particularly preferably extruded in a molten state on the embossed film 22. The base film 24 and the heat-shrinkable film 25 are wound substantially simultaneously, and (3) the embossed film 22 and the base film 24 and the heat-shrinkable film 25 are heat-fused on the embossing roll while being pressed. It is manufactured in the process of forming the bubble portion 3 by the process.

An example of a more specific manufacturing method will be described with reference to FIG. FIG. 5 illustrates a process of manufacturing the heat-shrinkable bubble buffer sheet 1 from the film 22 ′ (embossed film before embossing), the base film 24 and the heat-shrinkable film 25. Film 22 'and base film 2 manufactured by T-die film forming line
4 is a view for explaining a step of manufacturing the heat-shrinkable bubble buffer sheet 1 by using FIG. The film 22 ′ is extruded from the T-die 202, and the base film 24 is extruded from the T-die 203 and sent to the embossing roll 109.
When the resin component of the film is polyethylene, the temperature at the outlets of the T dies 202 and 203 is usually 210 to 250 ° C, and practically preferably 230 to 250 ° C.

In the embossing roll 109, the molten film 22 ′ before embossing is sucked at a degree of vacuum of 40 to 100 hPa by a vacuum pump while gradually cooling.
A large number of embosses 21 are formed on a film 22 ′ to form an embossed film 22. While the embossed film 22, the base film 24, and the heat shrinkable film 25 are pressed by the press roll 121, they are heat-fused on the emboss roll 109 to form the bubble portion 3. Then, the cooling roll 1
By 11, the heat-shrinkable bubble buffer sheet 1 is formed while being cooled while being pressed against the embossing roll 109. The buffer sheet 1 formed by the embossing roll 109 is further cooled sufficiently via the roll 112.

Another preferred embodiment of the method for producing the heat-shrinkable bubble buffer sheet (heat-shrinkable bubble buffer sheet) of the present invention will be described with reference to FIGS. First, embossed film 2
2 and the base film 24, the same bubble buffer sheet 8 as in FIG. Furthermore, (1) heat shrinkable film 2
6 and the molten top film 27 are wound around the embossed film 22 of the bubble-absorbing sheet 8 so as to be in contact with the embossed portions or protrusions thereof.
And a top film 27 extruded in a molten state so as to be in contact with the embossed or protruded portion of the embossed film 22, and (2) the embossed or protruded portion, the heat-shrinkable film 26 and the top FIG. 4 shows a process in which the film 27 is thermally fused while being pressed.
Can be manufactured.

FIGS. 6 and 7 show a more specific embodiment. 6 and 7 show a process of manufacturing the heat-shrinkable bubble buffer sheet 7 by bonding the heat-shrinkable film 26 and the top film 27 or the heat-shrinkable film 26 and the top film 23 to the buffer sheet 8. is there. The top film 23 is a roll 115
Is preheated by the heating roll 116 and sent to the pressure bonding roll 118. Although the temperature of the heating roll 116 is maintained at or above the softening point of the top film 23, a preferred range is at or above the softening point of the top film 23,
It is a range of a temperature not higher than 10 ° C. higher than its melting point. The number of the heating rolls 116 does not have to be one, but is preferably three so that sufficient preheating can be performed. on the other hand,
The cushioning sheet 8 includes a pressing roll 118, a pressing roll 114
It is preferred to preheat before being sent to The top film 27 is a film extruded from a T-die in a molten state. The top film 23 illustrated in FIG. 7 is preferably heated by the heating roll 115 and the heating roll 116.

[0042]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to only these examples.

The characteristics of the resin were determined by the following measuring methods. (1) Density [g / cm ³ ]: In accordance with JIS K7112, a strand obtained at the time of measuring a melt flow rate under a load of 190 ° C. and a load of 2.16 Kg is heat-treated at 100 ° C. for 1 hour and allowed to reach room temperature over 1 hour. The cooled sample was measured using a density gradient tube. (2) Melt flow rate (MI) [g / 10 min]: J
It was determined by measuring the weight of the resin extruded into a strand in 10 minutes at 190 ° C. under a load of 2.16 kg using a melt indexer in accordance with IS.K7210.

(Evaluation of Heat Shrinkage Property) A 10 cm × 10 cm cut sample is prepared. In accordance with JIS Z1709, it was immersed in a glycerin bath for 20 seconds. For the sample after shrinkage, the shrinkage ratio was measured, and the occurrence of air bleeding in the bubble portion was visually observed.

Example 1 An embossed film was made of low-density polyethylene (MI: 2 g / 10 min, density: 0.928).
g / cm ³ ) and high density polyethylene (MI: 5.7 g /
A composition having a density of 0.963 g / cm ³ ) for 10 minutes was used. The base film is made of low density polyethylene (MI:
2 g / 10 min, density: 0.928 g / cm ³ ), linear low-density polyethylene produced by a metallocene catalyst (manufactured by Ube Industries, MI: 2.5 g / 10 min, density: 0.92)
5 g / cm ³ ), high density polyethylene (MI: 5.7 g)
/ 10 min, density: 0.963 g / cm ³ ), and a composition with 3 parts by weight (manufactured by Ube Industries, Ltd.) of a maleic acid-modified linear low-density polyethylene produced by a metallocene catalyst (addition amount of maleic acid: 300 ppm, density: 0.924
g / cm ³ ). 45g / m for embossed film
² , the base film was performed at 31 g / m ² . The heat-shrinkable film is a biaxially stretched polypropylene film simultaneously produced by the tubular method (Kojin Co., Kojin Polyset, thickness 15μ).
m) was used. The heat-shrinkable bubble buffer sheet was manufactured by the manufacturing method shown in FIG. The manufacturing conditions were as follows: emboss roll temperature: 90 ° C., seal roll temperature: 20 ° C., molding speed:
The test was performed at 7 m / min and the die temperature of the T-die: 250 ° C. The heat-shrinkable film was wound on a pressure roll, and a base film extruded from a T-die was further wound, and bonded to the embossed film and the embossed roll by heat fusion. The heat shrinkability of the obtained heat shrinkable bubble buffer sheet was evaluated. Heat shrink temperature (glycerin bath temperature) 110 ° C ~
At a temperature between 120 ° C and the shrinkage ratio in the range of 8 to 25%, no air leakage was observed.

Example 2 As a heat-shrinkable film, a multilayer biaxially stretched film (Ecosoft G, manufactured by Ube Film Co., Ltd.)
P, polyolefin-based biaxial stretching) to obtain a heat-shrinkable bubble buffer sheet in the same manner as in Example 1. The heat shrinkability of the obtained heat shrinkable bubble buffer sheet was evaluated. Heat shrink temperature (glycerin bath temperature) 110 ° C-12
At a temperature between 0 ° C. and the shrinkage ratio in the range of 8 to 20%, no air leakage was observed.

[0047]

The heat-shrinkable bubble-absorbing sheet of the present invention can be recycled by a method such as melting or decomposition because all the resins are not cross-linked. Can be suppressed. The heat-shrinkable bubble-absorbing sheet of the present invention can be easily manufactured without greatly impairing the heat-shrinkability of the heat-shrinkable film by laminating the heat-shrinkable film to a film layer in a molten state extruded from a T-die or the like. can do.

[Brief description of the drawings]

FIG. 1 is an explanatory view of one embodiment of a heat-shrinkable bubble buffer sheet of the present invention.

FIG. 2 is a cross-sectional view of the heat-shrinkable bubble buffer sheet of one embodiment of the present invention shown in FIG.

FIG. 3 is an explanatory view of one embodiment of the heat-shrinkable bubble buffer sheet of the present invention.

FIG. 4 is a cross-sectional view of the heat-shrinkable bubble buffer sheet of one embodiment of the present invention shown in FIG.

FIG. 5 shows an embossed film and a base film as T
Direct production of film from die film forming line,
It is explanatory drawing of one Embodiment of the process of manufacturing a heat-shrinkable bubble buffer sheet.

FIG. 6 is an explanatory view of one embodiment of a process for producing a heat-shrinkable bubble buffer sheet by directly producing a film from a T-die film forming line as a top film.

FIG. 7 is an explanatory view of one embodiment of a process for producing a heat-shrinkable bubble buffer sheet.

[Explanation of symbols]

1, 7: heat-shrinkable bubble buffer sheet, 8: bubble buffer sheet, 3: convex closed cell portion (emboss) of embossed film, 21: embossed, 22: embossed film, 23, 27: top film, 24: Base film, 25, 26: heat shrink film, 108: temperature control roll, 115, 116: heating roll, 114, 118, 121: pressure roll, 109: emboss roll, 111, 112: cooling roll, 202, 203, 204 : T-die.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) // B29K 23:00 B29L 7:00 B29L 7:00 31:58 31:58 B65D 81/14 C (72 ) Inventor Katsumi Kimura 8-1, Goi Minami Coast, Ichihara-shi, Chiba Ube Film Co., Ltd. Ichihara Plant (72) Inventor Toshiaki Shimada 8-1 Goi South Coast, Ichihara-shi, Chiba Ube Film Co., Ltd. Ichihara Plant F-term (reference) 3E066 AA24 CA01 CB03 4F100 AK01A AK01B AK01C AK01D AK04 AK04B AK04D AK06 AK07 AK25B AK25D AK53 AK70B AK70D AL04B AL04D AL05B AL05D BA03 BA04 BA07 BA10A BA10C BA10D DD04A DD22A EC03 EC032 EH17 EH171 EJ05C GB90 JK08C JK11 4F211 AA04E AA05 AA11 AA21E AC01 AD08 AG03 AG20 SA04 SA09 SA11 SC07 SD01 SD11 SD21 SG01 SH06 SP01 SP36 SW06 SW15

Claims (6)

[Claims] 1. An embossed film having a number of convex protrusions formed thereon, a planar base film bonded to a surface of the embossed film where the convex protrusions are not formed to form convex closed cells, A heat-shrinkable non-crosslinked heat-shrinkable film bonded to the embossed film or the base film. 2. An embossed film having a large number of projections formed thereon, a planar base film bonded to a surface of the embossed film on which the projections are not formed to form convex closed cells, A top film on a plane bonded to the top surface of the convex protrusion of the embossed film, and a non-crosslinked heat-shrinkable film bonded to the top film or the base film. Heat-shrinkable bubble buffer sheet. 3. The method according to claim 1, wherein at least one of the base film and the top film is an unsaturated carboxylic acid-grafted polyethylene obtained by grafting 0.01 to 5 parts by weight of an unsaturated carboxylic acid to 100 parts by weight of polyethylene. The heat-shrinkable bubble buffer sheet according to claim 1. 4. A plastic film is wound around an embossing roll having a large number of recesses on its peripheral surface to form convex projections, and is extruded in a molten state onto the embossing film having the convex projections on the embossing roll. Heat-shrinkable bubble buffer, characterized in that the heat-shrinkable film that has not been crosslinked is further wound so as to come into contact with the base film, and is heat-sealed on an embossing roll at substantially the same time as the wound base film is wound. Sheet manufacturing method. 5. An air bubble buffer sheet having a plurality of closed cells having a plurality of convex protrusions formed thereon and a flat base film bonded thereto, and pressure-bonded to a top surface of the convex protrusions of the emboss film of the bubble buffer sheet having convex closed cells. At the same time as winding the top film extruded in a molten state on a roll, a non-crosslinked heat-shrinkable film is further wound so as to come into contact with the top film, and thermally fused on a pressure roll. A method for producing a heat-shrinkable bubble buffer sheet. 6. At least one of the base film and the top film is an unsaturated carboxylic acid-grafted polyethylene obtained by grafting 0.01 to 5 parts by weight of an unsaturated carboxylic acid to 100 parts by weight of polyethylene. The method for producing a heat-shrinkable bubble buffer sheet according to claim 4.