JP2001113585A - Method of manufacturing foamed laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a foamed laminate having a foam layer and a gas-barrier resin layer which prevents the resin layer from being thinned extremely and being broken in vacuum forming, simple in terms of a process, and can reduce production costs. SOLUTION: A production method has a melt-kneading process in which in the first extruder 3, a resin for forming a foamed polyolefin layer is melted and mixed with a foaming agent supplied from a foaming agent supply apparatus 6 to produce a material for forming the foamed polyolefin layer, a melting process in which in the second extruder, a material for forming a non-foamed polyolefin layer is melted, a coextrusion process in which the molten material for forming the foamed layer and the molten material for forming the non- foamed layer are coextruded under the atmospheric pressure by an extrusion die 7 to form a foamed multi-layer polyolefin sheet 15, and a lamination process in which a gas-barrier resin film 36 supplied from a gas-barrier resin film supply apparatus 23 is laminated on the sheet 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a laminated foam having a gas barrier resin layer,
More specifically, the present invention relates to a method for producing a laminated foamed sheet suitable for containers requiring gas barrier properties, heat insulation properties, light weight, etc., such as food containers.

[0002]

2. Description of the Related Art As a conventional method for producing a foamed sheet having a gas barrier resin layer, the following techniques are known. (1) A method of laminating a foam sheet and a gas barrier resin layer using an adhesive. (2) A method in which the foam sheet forming material and the gas barrier resin layer forming material are co-extruded with a single extrusion die using separate extruders.

[0003]

However, according to the technique (1), when laminating using an adhesive,
In addition to the step of manufacturing a polyolefin foam sheet, a separate bonding step including an adhesive coating layer step is required, which increases the manufacturing cost and causes the organic solvent contained in the adhesive to remain in the product, resulting in a food container In addition, the problem of elution into food cannot be avoided.

According to the technique (2), a bonding step is not required, and problems such as residual organic solvent can be avoided. However, since it is formed by co-extrusion with another layer, a gas barrier resin layer is formed. It is difficult to adjust the thickness of the gas barrier resin layer only, so that the thickness of the gas barrier resin layer varies greatly. There is a case where the non-existent portion occurs due to the destruction of the conductive resin layer, and the quality is deteriorated in the preservation of food.

[0005] Further, according to the co-extrusion technique, even the gas barrier resin layer foams, and the gas barrier property may not be sufficiently exhibited.

An object of the present invention is to provide a foam layer and a gas-barrier resin layer so that the gas-barrier resin layer does not become extremely thin or break when vacuum-formed, and the process is simple. It is another object of the present invention to provide a method for producing a laminated foam capable of reducing the production cost.

[0007]

SUMMARY OF THE INVENTION The present invention provides at least one
A method for producing a laminated foam comprising a polyolefin foam layer, at least one non-foamed polyolefin layer, and at least one gas-barrier resin layer, wherein the polyolefin foam layer constituent material is extruded. At least one having a blowing agent supply device for supplying a blowing agent
A first extruder, at least one second extruder that extrudes the polyolefin non-foamed layer constituent material, and co-extrudes the polyolefin foamed layer constituent material and the polyolefin non-foamed layer constituent material to form a multilayer polyolefin foam sheet. At least one extrusion die to be formed and at least one gas barrier resin film supply device for supplying a gas barrier resin film having at least one gas barrier resin layer to the multilayer polyolefin foam sheet in a stackable manner are provided. In the first extruder, the resin material constituting the polyolefin foam layer is melted, and the melted resin material constituting the polyolefin foam layer and the blowing agent supplied from the foaming agent supply device are mixed in the first extruder. Melt kneading process to make a polyolefin foam layer constituent material,
In the second extruder, a melting step of melting the polyolefin non-foamed layer constituent material, and in the extrusion die, coextruding the polyolefin foamed layer constituent material and the polyolefin non-foamed layer constituent material in a molten state under atmospheric pressure to form the polyolefin A co-extrusion step of foaming a foam layer constituent material to form a multilayer polyolefin foam sheet, and supplying a gas barrier resin film from at least one of the gas barrier resin film supply devices, and forming a multilayer polyolefin foam sheet and a gas barrier resin film. Characterized by having a laminating step of laminating

[0008] With the above structure, the gas barrier resin layer has a foam layer and a gas barrier resin layer, and when vacuum formed, the gas barrier resin layer is not extremely thinned or broken, and the process is simple. Thus, it is possible to provide a method for producing a laminated foam that can reduce the production cost. The gas barrier resin layer of the laminated foam is formed using a gas barrier resin film having a gas barrier resin layer separately manufactured, and as a result, a film whose thickness and thickness accuracy are adjusted can be used. The thickness distribution Tmax / Tmin of the gas barrier resin layer in the laminated foam in a measurement within a range of at least 25 cm ² is set to 1.0 to 1.
2, and the thickness T can be adjusted to 10 to 200 μm. Also, there is no need to provide a separate bonding process,
The process is simple. Note that Tmax and Tmin are:
The maximum and minimum values of the measured thickness are shown. Tmax / Tmin is 1.0 to 1.0 over a wide measurement range of 25 cm ² or more.
The range of 2 is preferable because the uniformity is higher.

In the laminated foam of the present invention, the simplest basic structure is a gas barrier resin layer / non-foam layer / foam layer, and a non-foam layer / foam layer / gas barrier resin layer.
It is preferably a four-layer structure of gas barrier resin layer / non-foam layer / foam layer / non-foam layer, and a five-layer structure of non-foam layer / foam layer / gas barrier resin layer / foam layer / non-foam layer. ,
Six-layer structure of gas barrier resin layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer, or gas barrier resin layer / non-foam layer / foam layer / non-foam layer / non-foam layer / foam layer / Non-foamed layer, or non-foamed layer / foamed layer / non-foamed layer / gas barrier resin layer / non-foamed layer / foamed layer / non-foamed layer. Further, the layers may be stacked so as to have a structure having more layers than the above structure.

Preferred embodiments of the above-mentioned production method include the following. According to a second aspect of the present invention, in the method for producing a laminated foam according to the first aspect,
The manufacturing apparatus includes one of the first extruder and the second extruder, and includes a circular die as the extrusion die. The co-extrusion process includes a polyolefin foam layer constituent material and a polyolefin non-foam layer constituent The material is co-extruded in a cylindrical shape to form a multilayered polyolefin foamed sheet, and the cylindrical multilayered polyolefin foamed sheet is cut at two locations in the length direction to form two multilayered polyolefin foamed sheets. Including a cutting step, the laminating step is to supply a gas barrier resin film between the two multilayer polyolefin foam sheets, and to laminate the two multilayer polyolefin foam sheets on both surfaces of the gas barrier resin film. There is a feature.

According to this method, for example, when a gas barrier resin single-layer film is used as the gas barrier resin film, a non-foamed layer / foamed layer / non-foamed layer / gas barrier resin layer / non-foamed layer / foamed layer / non-foamed A laminated foam having a configuration of a layer can be easily produced. When a multilayer film including a gas barrier resin layer and another resin layer is used as the gas barrier resin film, a laminated foam including the layer configuration of the multilayer film can be easily manufactured. For example, when a gas barrier resin film having a three-layer structure of adhesive resin layer / gas barrier resin layer / adhesive resin layer is used, the obtained laminated foam will have a non-foam layer / foam layer /
It has a structure of non-foamed layer / adhesive resin layer / gas barrier resin layer / adhesive resin layer / non-foamed layer / foamed layer / non-foamed layer.

The multi-layer gas barrier resin film is not limited to the three-layer structure described above, but has a structure such as a non-stretched polyolefin resin layer / adhesive resin layer / gas barrier resin layer / adhesive resin layer. There may be.

According to a third aspect of the present invention, in the method for producing a laminated foam according to the first aspect, the production apparatus includes one of the first extruder and the second extruder, and It has a circular die as a die,
The co-extrusion step is to form a multilayer polyolefin foam sheet by co-extruding a polyolefin foam layer constituent material and a polyolefin non-foam layer constituent material in a cylindrical shape,
The multi-layered polyolefin foamed sheet includes a cutting step of cutting the cylindrical multi-layered polyolefin foamed sheet at two locations in the length direction to form two multi-layered polyolefin foamed sheets. At least one gas barrier resin film is supplied so as to overlap the side not facing the other multilayer polyolefin foam sheet, and the gas barrier resin film and the two multilayer polyolefin foam sheets are laminated. There is a feature.

According to this method, for example, gas barrier resin layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer, or gas barrier resin layer / non-foam layer / foam layer / non-foam layer / A laminated foam having a configuration of non-foamed layer / foamed layer / non-foamed layer can be easily produced.
A multi-layer laminated foam in which both surface layers are gas barrier resin layers can also be easily produced.

According to a fourth aspect of the present invention, the manufacturing apparatus includes one of the first extruder and the second extruder, and a circular die as the extrusion die. A multi-layer polyolefin foam sheet is formed by co-extruding a polyolefin foam layer constituent material and a polyolefin non-foam layer constituent material in a cylindrical shape, and the cylindrical multi-layer polyolefin foam sheet is formed at one location in the longitudinal direction. An incision step for incision is provided, wherein the laminating step supplies a gas barrier resin film to at least one surface of the cut multilayer polyolefin foam sheet, and laminates the gas barrier resin film and the multilayer polyolefin foam sheet. Features.

According to this method, for example, a laminated foam having a structure of gas barrier resin layer / non-foamed layer / foamed layer / non-foamed layer can be easily produced.
A multi-layer laminated foam in which both surface layers are gas barrier resin layers can also be easily produced.

According to a fifth aspect of the present invention, there is provided a flat die having one of the first extruder and the second extruder, the flat die having two extrusion openings parallel to each other. Are provided as the extrusion dies. In the co-extrusion step, a polyolefin foamed layer constituent material and a polyolefin non-foamed layer constituent material are supplied to the respective extrusion openings and co-extruded to form two multilayer polyolefin foamed sheets. In the laminating step, a gas barrier resin film is supplied between the two multi-layer polyolefin foam sheets, and the gas barrier resin film and the two multi-layer polyolefin foam sheets are laminated. There is a feature.

According to this method, for example, a structure of non-foamed layer / foamed layer / gas barrier resin layer / foamed layer / non-foamed layer or non-foamed layer / foamed layer / non-foamed layer / gas barrier resin layer /
A laminated foam having a configuration of non-foamed layer / foamed layer / non-foamed layer can be easily produced.

According to a sixth aspect of the present invention, there is provided a flat die having one of the first extruder and the second extruder, the flat die having two extrusion openings parallel to each other. Is provided as the extrusion die, and in the co-extrusion step, a polyolefin foam layer constituent material and a polyolefin non-foam layer constituent material are supplied to the extrusion openings, respectively, and co-extruded to form two multilayer polyolefin foam sheets. Wherein the laminating step comprises supplying a gas barrier resin film to at least one outer surface of the two multilayer polyolefin foam sheets, and laminating the gas barrier resin film and the two multilayer polyolefin foam sheets. It is characterized by being.

According to this method, for example, a gas barrier resin layer / non-foamed layer / foamed layer / non-foamed layer or a gas barrier resin layer / non-foamed layer / foamed layer / foamed layer / non-foamed layer or a gas barrier property Resin layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer, or gas barrier resin layer / non-foam layer / foam layer / non-foam layer / non-foam layer / foam layer / non-foam layer Can be easily produced, and further, a multilayer foam having two layers in which both surface layers are gas barrier resin layers can be easily produced.

According to a seventh aspect of the present invention, the manufacturing apparatus includes one of the first extruder and the second extruder, and has one extrusion opening as the extrusion die.
A base flat die is provided, and both dies are installed so that extrusion openings are parallel to each other. In the co-extrusion step, a polyolefin foam layer constituent material and a polyolefin non-foam layer constituent material are each separated by two. And supplying the same to a base flat die to form two multi-layer polyolefin foam sheets by co-extrusion. In the laminating step, a gas barrier resin film is supplied between the two multi-layer polyolefin foam sheets, Characterized in that the conductive resin film and the two multi-layer polyolefin foam sheets are laminated.

According to this method, a laminated foam having a five-layer structure of a non-foamed layer / foamed layer / gas barrier resin layer / foamed layer / non-foamed layer or a non-foamed layer / foamed layer / non-foamed layer / gas barrier resin A laminated foam having a seven-layer structure of layer / non-foamed layer / foamed layer / non-foamed layer can be easily produced.

According to an eighth aspect of the present invention, the manufacturing apparatus includes the first extruder and the second extruder, each having one extrusion opening as the extrusion die.
The two co-extrusion steps comprise a polyolefin foam layer constituent material and a polyolefin non-foam layer constituent material, each of which is provided with two flat dies. It is supplied to a flat die and co-extruded to form two multilayer polyolefin foam sheets, and the laminating step supplies a gas barrier resin film to at least one outer surface of the two multilayer polyolefin foam sheets, The gas barrier resin film and the two multilayer polyolefin foam sheets are laminated.

According to this method, for example, the structure of gas barrier resin layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer or gas barrier resin layer / non-foam layer / foam layer / non-foam layer A laminated foam having a structure of layer / non-foamed layer / foamed layer / non-foamed layer can be easily manufactured. Furthermore, a laminated foam in which both surface layers are gas barrier resin layers can be easily produced.

[0025] According to a ninth aspect of the present invention, the manufacturing apparatus comprises two first extruders and two second extruders, and two extruding dies selected from flat dies and circular dies. A multi-layer polyolefin foam sheet manufacturing apparatus including a die, wherein the first extruder, the second extruder, and the extrusion die are disposed one by one. The foamed layer constituting material and the polyolefin non-foamed layer constituting material are supplied to the respective multilayer polyolefin foamed sheet manufacturing apparatuses and co-extruded to form two multilayered polyolefin foamed sheets. A film is supplied between the two multi-layer polyolefin foam sheets, and a gas barrier resin film and the two multi-layer polyolefin foam sheets are provided. And characterized in that laminating a polyolefin foam sheet.

According to this method, a laminated foam having a five-layer structure of a non-foamed layer / foamed layer / gas barrier resin layer / foamed layer / non-foamed layer or a non-foamed layer / foamed layer / non-foamed layer / gas barrier resin A laminated foam having a seven-layer structure of layer / non-foamed layer / foamed layer / non-foamed layer can be easily produced.

[0027] According to a tenth aspect of the present invention, the manufacturing apparatus includes two first extruders and two second extruders, and two extruding dies selected from flat dies and circular dies. Equipped with dice,
The first extruder, the second extruder, and the extrusion die each include two multilayer polyolefin foam sheet manufacturing apparatuses in which one each is disposed, and the co-extrusion step includes a polyolefin foam layer constituent material. And the polyolefin non-foamed layer constituting material are supplied to the respective multi-layer polyolefin foam sheet production apparatuses and co-extruded to form two multi-layer polyolefin foam sheets, and the laminating step comprises forming the two multi-layer polyolefin foam sheets. A gas barrier resin film is supplied to at least one side of the sheet, and the gas barrier resin film and the two multilayer polyolefin foam sheets are laminated.

According to this method, for example, a gas barrier resin layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer or a gas barrier resin layer / non-foam layer / foam layer / non-foam layer A laminated foam having a structure of layer / non-foamed layer / foamed layer / non-foamed layer can be easily manufactured. Further, a laminated foam in which both surface layers (outermost layers) are gas barrier resin layers can be easily produced.

The lamination is preferably performed by heat fusion.

Each of the above-mentioned methods preferably further comprises a decompression step of passing the multilayer polyolefin foam sheet or the laminated foam through a decompression chamber to increase the expansion ratio of the foam layer. There is an advantage that the expansion ratio can be easily adjusted to a high level.

Before at least one of the laminating step and the depressurizing step, a preheating step of preheating the multi-layer polyolefin foam sheet or the laminated foam is further provided. It is effective for securing and is a preferable mode.

[0032]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a production apparatus suitable for producing a laminated foam of the present invention and a state in which a laminated foam is produced using the apparatus. In this example, polypropylene is used for the foam layer, and a multi-layer polyolefin foam sheet having a non-foam layer on both sides of the foam layer is formed into a tube shape (cylindrical shape) by coextrusion. A multilayer foam having a gas barrier resin layer by continuously cutting in the length direction to form two multi-layer polyolefin foam sheets having the same width, supplying a gas barrier resin film between them, and laminating them. Have gained. For example, when a gas barrier resin single-layer film is used as the gas barrier resin film, the laminated foam obtained by this method has a non-foam layer / foam layer / non-foam layer /
7 of gas barrier resin layer / non-foamed layer / foamed layer / non-foamed layer
It has a layered structure. When a multilayer film including a gas barrier resin layer and another resin layer is used as the gas barrier resin film, a laminated foam including the layer configuration of the multilayer film can be easily manufactured. For example, when a gas barrier resin film having a three-layer structure of an adhesive resin layer / gas barrier resin layer / adhesive resin layer is used, the obtained laminated foam will have a non-foam layer / foam layer / non-foam layer / adhesive resin. layer/
It has a structure of gas barrier resin layer / adhesive resin layer / non-foamed layer / foamed layer / non-foamed layer.

The production apparatus 1 shown in FIG. 1 comprises a first extruder 3 for extruding a polypropylene foam sheet layer and a second extruder 3 for extruding a non-foamed layer.
Extruder 5, Extrusion die 7, Mandrel 9, Cutter 3
0, roller 32, gas barrier resin film raw material 3
4 and a take-off roller 11.

The first extruder 3 is provided with a pump 6 for supplying carbon dioxide as a foaming agent. The polypropylene resin introduced from the hopper into the cylinder of the first extruder 3 is melted while being sent in the direction of the extrusion die 7 by a screw. The carbon dioxide gas is supplied to the molten resin when the resin is sufficiently melted, and is further uniformly dispersed and sent to the extrusion die 7. A configuration in which a known vent-type extruder is used as the first extruder and carbon dioxide gas is supplied under pressure from the vent hole without particularly requiring improvement of the extruder is a preferable embodiment.

The polyolefin resin constituting the non-foamed layer is melted by the second extruder 5 and fed to an extrusion die 7 (hereinafter sometimes simply referred to as a die). The type of the extrusion die 7 is not particularly limited as long as the internal structure is a structure suitable for forming a multilayer sheet. A flat die such as a T die, a coat hanger die, a circular die such as a straight die or a crosshead die is used. Is exemplified.

In a preferred embodiment, a gear pump is provided between the first extruder 3 and the extrusion die 7. By disposing the gear pump, the uniformity of the resin extrusion speed and the discharge amount can be increased, and the variation in the thickness of the foam layer can be reduced.

The multilayer foam sheet fed out of the extrusion die 7 in the form of a tube is preferably formed into a tube 15 having a predetermined diameter by the mandrel 9. By using a mandrel having a desired size, a foamed sheet layer having a desired width and thickness can be easily produced.

The mandrel 9 has a function of expanding the extruded multilayer polyolefin foam sheet in a direction perpendicular to the extrusion direction, and has an expansion ratio of 1.5 to 1.5.
It is preferably 4.5 times. It is also a preferable embodiment to form fine irregularities on the surface of the mandrel 9 for improving the slipperiness.

In the production of the multi-layer polyolefin foam sheet, it is preferable that after the co-extrusion step, an expansion step of expanding the co-extruded multi-layer polyolefin foam sheet in a direction perpendicular to the extrusion direction by an expansion device is preferably provided. is there.

The enlargement step makes it possible to easily produce a thin sheet which is difficult to produce only by simple extrusion. Further, since the sheet is expanded after extrusion, it is possible to produce a wide sheet using a small-diameter extruder.

When a flat die such as a T die is used as the extrusion die, it is a preferred embodiment to use a tenter such as a clip tenter or a pin tenter as the enlarging device.

In the production of the multi-layer polyolefin foam sheet, in the co-extrusion step, the resin amount extruded from the extrusion die is Q (kg / h), and the die slip diameter is W (m
When m) is satisfied, it is preferable that the reaction is performed under the condition of 10 ≧ Q / W ≧ 0.3, and more preferably, Q / W is 0.5 or more.

If the Q / W is less than 0.3, the bubbles may become coarse or the appearance of streaks may be poor. If the Q / W exceeds 10, the equipment cost increases.

The multi-layer polypropylene foam sheet 15 having a non-foamed layer formed on both surfaces after passing through the mandrel 9 is cut by a cutter 30 and formed into two flat sheets by a roller 32. A gas barrier resin film raw material 34 is disposed between the two multilayer polypropylene foam sheets 15, and the unwound gas barrier resin film 36 is provided.
Is fed between two multi-layer polypropylene foam sheets 15 and pressed by the take-off roller 11 (lamination step) to form a laminated foam sheet. The gas barrier resin film 36 is made of two multi-layer polypropylene foam sheets 1
It is a preferable embodiment to provide a preheating step of heating the lamination surface before laminating with 5.

FIG. 5 is a diagram showing a cross-sectional shape of a circular die suitable for carrying out the present invention, used in the manufacturing apparatus shown in FIG.

In the circular die 7 used in this example, the flow paths 23a and 23b of the resin forming the foamed layer are provided.
And the flow paths 24, 24a, 24 of the resin forming the non-foamed layer
b, 24c and 24d are formed.

The head 21 of the first extruder 3 is connected to the end of the die 7 on the source flow side in the resin flow direction, and the head 22 of the second extruder 5 is connected to the source flow side. Head 2
The molten resin forming the foam layer supplied from 1 first enters the flow path 23a and is sent toward the die exit. On the way, it is branched by passing through the path P and sent to the flow path 23b.

On the other hand, the molten resin forming the non-foamed layer is the second resin.
It is supplied from the head 22 of the extruder 5 and
a, 24b, and supplied so as to adhere to both surfaces of the flow path 23b so as to cover both surfaces of the foam layer, and are multi-layered at 25a. The molten resin supplied to the flow paths 24a and 24b passes through a divided flow path (not shown) similar to the path P so as to cover both surfaces of the foam layer of the flow path 23a.
4c and 24d, and are multi-layered at 25b.

The molten resin having a three-layer cylindrical shape at 25 a and 25 b is extruded from a die outlet 26.
By opening to the atmospheric pressure, the carbon dioxide gas in the resin constituting the foam layer expands, and bubbles are formed to form a foam layer.

The material constituting the foamed layer and the material constituting the non-foamed layer are laminated and extruded in the extrusion die 7, and the residence time in the extrusion die 7 after lamination is preferably 0.1 to 20 seconds. Yes, more preferably 0.5 to 15 seconds.

FIG. 2 shows another example of a production apparatus suitable for producing a laminated foam of the present invention and a state in which a laminated foam is produced using the apparatus. This example is different from the production apparatus shown in FIG. 1 in the supply of the gas barrier resin film and the lamination position. That is, using an extrusion device and a mandrel 9 having the same configuration as the device shown in FIG.
A multi-layer polyolefin foam sheet 15 formed by co-extrusion into a tubular (cylindrical) multi-layer polyolefin foam sheet 15 is continuously cut in the length direction at two locations,
The two multi-layer polyolefin foam sheets are laminated by a take-off roller 11 to form a laminated polyolefin foam sheet 5.
Set to 0. A gas barrier resin film 36 is supplied from a raw material (not shown) to a downstream position of the flow of the sheet via a guide roller 41, and is laminated on the laminated polyolefin foam sheet 50 by a pressure roller 42, so that a gas barrier resin film 36 is formed. The laminated foam S3 having the conductive resin layer is obtained. The laminated foam S3 obtained by this method has a six-layer structure of a gas barrier resin layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer or a gas barrier resin layer / non-foam layer / foam layer. It has a seven-layer structure of / non-foamed layer / non-foamed layer / foamed layer / non-foamed layer.

A gas barrier resin layer is further laminated on the opposite surface of the laminated polyolefin foam sheet 50, and the gas barrier resin layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer / gas barrier resin layer 7 Layer structure or gas barrier resin layer / non-foamed layer / foamed layer / non-foamed layer / non-foamed layer /
An eight-layer laminated foam having a gas barrier resin layer on both sides of a foamed layer / non-foamed layer / gas barrier resin layer can also be obtained.

FIG. 2 shows an example in which a pressure roller 42 is provided for laminating the gas barrier resin film 36. However, without providing the pressure roller 42, the multi-layer polyolefin sheet is And taking over, and gas barrier resin film 36
Is also preferable from the viewpoint of simplification of the apparatus.

FIG. 3 shows another example of a production apparatus suitable for producing a laminated foam of the present invention and a state in which a laminated foam is produced using the apparatus. In this example, a multi-layer polyolefin foam sheet formed in a tubular (cylindrical) shape by coextrusion is continuously cut at one location in the length direction to form one multi-layer polyolefin foam sheet, and is guided flat by a roller 32. After that, the take-up roller 11 is laminated with the gas barrier resin film 36 supplied from the raw material via the guide roller 41 to form a laminated foam S
2 is manufactured.

The laminated foam obtained by this method has a four-layer structure of a gas barrier resin layer / non-foamed layer / foamed layer / non-foamed layer. Here, the example in which the gas barrier resin film is laminated on only one surface of the multilayer polyolefin foam sheet is shown. However, the gas barrier resin film 36 is supplied and laminated on both surfaces of the multilayer polyolefin foam sheet, thereby forming a gas barrier resin film. Resin layer / non-foamed layer /
A laminated foam having a five-layer structure of a foamed layer / non-foamed layer / gas barrier resin layer can also be obtained.

FIG. 4 shows a method of manufacturing a laminated foam S2 having a layer structure the same as the layer structure shown in FIG. 3 and a narrow sheet. In the method shown in FIG. 4, the multi-layer polypropylene foam sheet 15 having a non-foamed layer formed on both surfaces passing through the mandrel 9 is attached to the cutter 3.
The steps from the incision at 0 to the formation of two flat sheets 15 by the rollers 32 are exactly the same as the method shown in FIG. The obtained two multi-layer polypropylene foam sheets 15, 15 are separately guided and supplied by the guide rollers 41a, 41b from the outside of each foam sheet with the gas barrier resin film 36 and the pressure rollers 42a,
42b, and two laminated foams S2 are produced.

The manufacturing apparatus shown in FIG.
It has one second extruder 5 and one extrusion die 7 which is a flat die. The flat die is provided with two extrusion openings 7a and 7b parallel to each other. The path P is formed so that the non-foamed layer constituting material is supplied to both sides of the foamed layer constituting material. When this apparatus is used, in the co-extrusion step, the polyolefin foam layer constituent material and the polyolefin non-foam layer constituent material are
By supplying to the extrusion openings and co-extrusion, two multi-layer polyolefin foam sheets 15 having a two-layer structure of a non-foam layer / foam layer are formed. In the laminating step, the gas barrier resin film 36 By supplying and laminating between the multi-layered polyolefin foam sheets 15, a laminated foam is manufactured. The laminate is preferably laminated so that the non-foamed layer is on the outside, and the laminated foam obtained by this method has a five-layer structure of non-foamed layer / foamed layer / gas barrier resin layer / foamed layer / non-foamed layer.

Instead of the dice used in the apparatus illustrated in FIG. 6, the dice used in FIG. 10 can be used.
When the die illustrated in FIG. 10 is used, the foamed layer constituting material is first divided into two, and the non-foamed layer constituting material can be supplied to both surfaces of each divided foamed layer constituting material.
When co-extruded using a die having such a structure, a non-foamed layer /
Two multi-layer polyolefin foam sheets having a three-layer structure of a foam layer / non-foam layer can be formed. By supplying and laminating a gas barrier resin film between these multilayer foam sheets, seven layers of non-foam layer / foam layer / non-foam layer / gas barrier resin layer / non-foam layer / foam layer / non-foam layer A laminated foam having a structure can be obtained.

The flat die 7 shown in FIG. 10 has extrusion openings 7a and 7b, a flow path 44 for receiving the supply of the foam layer forming material from the first extruder, and supplying the non-foaming layer forming material from the second extruder. A receiving channel 48 is formed. The foam layer constituent material is divided from the flow path 44 into the flow paths 45 and 46, and the non-foam layer constituent material is divided from the flow path 48 after the division into the flow path 4.
7 and 49, and are supplied to both sides through the extrusion openings 7a and 7
b.

The embodiment shown in FIG. 7 is the same as that shown in FIG. 6 until two multi-layer polyolefin foam sheets 15 are produced. In this example, a laminated foam having a gas barrier resin layer as a surface layer is obtained by supplying and laminating the gas barrier resin film from outside one of the multilayer polyolefin foam sheets 15. The laminated foam obtained by this method has a four-layer structure of gas barrier resin layer / non-foam layer / foam layer / non-foam layer or gas barrier resin layer /
It has a five-layer structure of non-foamed layer / foamed layer / foamed layer / non-foamed layer. By supplying a gas barrier resin film from both outer surfaces of the two multilayer polyolefin foam sheets 15 and 15 and further laminating them, a gas barrier resin layer / non-foam layer / foam layer / non-foam layer / gas barrier resin layer It is also possible to obtain a laminated foam having a five-layer structure or a six-layer structure of a gas barrier resin layer / non-foam layer / foam layer / foam layer / non-foam layer / gas barrier resin layer.

When the dice used in FIG. 10 is used in place of the dice used in the apparatus illustrated in FIG. 7, the foam layer forming material is first divided into two parts, and the non-foaming layer forming material is supplied to both sides. Co-extruded. As a result, two multi-layered polyolefin foamed sheets having a three-layer structure of a non-foamed layer / foamed layer / non-foamed layer can be formed, and a gas barrier resin film is supplied to the two multi-layered polyolefin foamed sheets from the outside. If laminated, a gas barrier resin layer / non-foamed layer / non-foamed layer / a non-foamed layer / 6-layer structure of gas barrier resin layer / non-foamed layer / foamed layer / non-foamed layer / non-foamed layer
A laminated foam having a seven-layer structure of a foamed layer / non-foamed layer / non-foamed layer / foamed layer / non-foamed layer, or a gas barrier resin layer /
Non-foamed layer / foamed layer / non-foamed layer / foamed layer / non-foamed layer / gas barrier resin layer 7 layer structure or gas barrier resin layer /
A laminated foam having an eight-layer structure of a non-foamed layer / foamed layer / non-foamed layer / non-foamed layer / foamed layer / non-foamed layer / gas barrier resin layer can be obtained.

In the example shown in FIG. 8, the manufacturing apparatus is provided with a first extruder 3 and a second extruder 5 each, and two flat dies having one extrusion opening as the extrusion die 7. The two dies are installed such that the extrusion openings are parallel to each other. In the co-extrusion step, the polyolefin foam layer constituent material and the polyolefin non-foam layer constituent material are separately supplied to two flat dies, respectively, and co-extruded to form a two-layer polyolefin having a non-foam layer / foam layer two-layer structure. A foam sheet 15;
The two multilayer foam sheets are preferably formed so that the foam layers face each other. In the laminating step, a laminated foam is manufactured by supplying and laminating the gas barrier resin film 36 between the two multilayer polyolefin foam sheets 15. According to this method, 5 of non-foamed layer / foamed layer / gas barrier resin layer / foamed layer / non-foamed layer
A laminated foam having a layer structure is obtained.

The die 7 used in the apparatus shown in FIG. 8 has a structure in which the non-foamed layer forming material is supplied from one side of the foamed layer forming material. As a structure similar to a die, a configuration in which a non-foamed layer forming material is supplied to both sides of the foamed layer forming material may be adopted. By using such a die, for example, a laminated foam having a seven-layer structure of a non-foamed layer / foamed layer / non-foamed layer / gas barrier resin layer / non-foamed layer / foamed layer / non-foamed layer can also be obtained.

In the example shown in FIG. 8, two multilayer polyolefin foam sheets 15 are formed, and in the laminating step,
The gas barrier resin film 36 is supplied between the two multi-layer polyolefin foam sheets, and the three sheets are laminated. As in the example shown in FIG. By supplying and laminating the gas barrier resin film 36 from above, a laminated foam having a gas barrier resin layer on the surface layer may be obtained.
The laminated foam obtained by this method has a gas barrier resin layer / non-foam layer / foam layer / non-foam layer having a four-layer structure or a gas barrier resin layer / non-foam layer / foam layer / foam layer / non-foam layer. It has a five-layer configuration. Further, by supplying and laminating a gas barrier resin film on both outer surfaces of each of the two multi-layer polyolefin foam sheets, five layers of gas barrier resin layer / non-foam layer / foam layer / non-foam layer / gas barrier resin layer are formed. A laminated foam having a six-layer structure of a structure or a gas barrier resin layer / a non-foam layer / a foam layer / a foam layer / a non-foam layer / a gas barrier resin layer can also be obtained.

Further, by changing the internal structure of the die and supplying the non-foaming layer forming material to both sides of the foaming layer forming material in the same manner as in the above case, for example, the gas barrier resin layer / non-foaming layer A six-layer structure of / foam layer / non-foam layer / foam layer / non-foam layer or a seven-layer structure of gas barrier resin layer / non-foam layer / foam layer / non-foam layer / non-foam layer / foam layer / non-foam layer Laminated foam or gas barrier resin layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer /
7 layers of gas barrier resin layer or gas barrier resin layer / non-foam layer / foam layer / non-foam layer / non-foam layer / foam layer /
A laminated foam having an eight-layer structure of a non-foamed layer / gas barrier resin layer can be obtained.

The manufacturing apparatus shown in FIG. 9 includes two first extruders and two second extruders, and includes two dies selected from flat dies and circular dies as the extrusion dies. The first extruder 3, the second extruder 5, and the extrusion die 7 each include two multi-layer polyolefin foam sheet manufacturing apparatuses in which one set is provided.

In the co-extrusion step, the polyolefin foam layer forming material and the polyolefin non-foaming layer forming material are supplied to respective multi-layer polyolefin foam sheet manufacturing apparatuses and co-extruded to form two multi-layer polyolefin foam sheets 15. In the laminating step, the gas barrier resin film 36 is coated with the two multilayer polyolefin foam sheets 15.
And laminated to form a laminated foam.

Also in this case, depending on the internal structure of the die, for example, a non-foamed layer / foamed layer / gas barrier resin layer /
To obtain a laminated foam having a five-layer structure of a foamed layer / non-foamed layer or a seven-layered structure of a non-foamed layer / foamed layer / non-foamed layer / gas barrier resin layer / non-foamed layer / foamed layer / non-foamed layer Can be.

In the example shown in FIG. 9, the gas barrier resin film 3 is sandwiched between two multi-layer polyolefin foam sheets 15.
2, and two laminated polyolefin foam sheets 15 are formed, and in the laminating step, a gas barrier resin film is formed from the outside of one of them. And a laminated foam having a gas-barrier resin layer may be obtained by laminating the laminate. According to this method, for example, the gas barrier resin layer / non-foamed layer /
Four layers of foam layer / non-foam layer or five layers of gas barrier resin layer / non-foam layer / foam layer / foam layer / non-foam layer, or gas barrier resin layer / non-foam layer / foam layer / non-foam layer To produce a laminated foam having a seven-layer structure of 6 layers / foam layer / non-foam layer or gas barrier resin layer / non-foam layer / foam layer / non-foam layer / non-foam layer / foam layer / non-foam layer. Can be. In addition, by supplying and laminating a gas barrier resin film on both outer surfaces of two multi-layer polyolefin foam sheets, for example, a gas barrier resin layer / non-foam layer / foam layer / non-foam layer / gas barrier resin layer is formed. Layer structure or gas barrier resin layer / non-foam layer / foam layer / foam layer / non-foam layer / gas barrier resin layer 6
Layer configuration and seven layers of gas barrier resin layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer / gas barrier resin layer or gas barrier resin layer / non-foam layer / foam layer / non-foam A laminated foam having an eight-layer structure of layer / non-foamed layer / foamed layer / non-foamed layer / gas barrier resin layer can be obtained.

In laminating the multilayer polyolefin foam sheet formed by co-extrusion and the gas barrier resin film, it is a preferred embodiment to preheat at least one of them, but a known heating device can be used for preheating without any limitation. And a far-infrared heater, a hot air blowing device and the like are exemplified.

The raw materials used in the present invention will be described.
As polyolefins constituting the foam layer, ethylene,
Examples include homopolymers of propylene, butene, and the like, copolymers using two or more of these monomers, and copolymers of at least one of these monomers and other monomers. Examples of the copolymer include ethylene-α-
Examples thereof include an olefin copolymer and a propylene-α-olefin copolymer.

Polyethylene (PE) or a copolymer of ethylene and another monomer, that is, as the ethylene resin, for example, polyethylene such as low-density polyethylene and high-density polyethylene; ethylene-propylene copolymer, ethylene-butene-1 copolymer Polymer, ethylene-4-methyl-1
Ethylene-α such as pentene copolymer, ethylene-hexene-1 copolymer, ethylene-octene-1 copolymer, etc.
An olefin copolymer; an ethylene copolymer comprising a repeating unit derived from at least one vinyl monomer and a repeating unit derived from ethylene, such as an ethylene-methyl methacrylate copolymer and an ethylene-vinyl acetate copolymer. Coalescence, and mixtures thereof.

The propylene-α-olefin copolymer includes a propylene-α-olefin block copolymer,
Examples include propylene-based polymers such as propylene-α-olefin random copolymers and mixtures thereof. Examples of the α-olefin of the propylene-α-olefin block copolymer and the propylene-α-olefin random copolymer include ethylene, butene-1, and octene-1.
And α-olefins having 2 to 4 carbon atoms, such as

Among the polyolefins exemplified above, (a) a long-chain branched polypropylene can be obtained because the uniformity of the foam is high and the multi-layer polyolefin foam sheet of the present invention is particularly excellent in vacuum moldability. (P
P), (b) In the first step, a crystalline PP having an intrinsic viscosity of 5 dl / g or more is synthesized, and in a second step, a crystalline PP having an intrinsic viscosity of less than 3 dl / g is continuously synthesized. Has a PP of 0.05 to 25 wt% and an intrinsic viscosity of 3 dl as a whole.
A suitable raw material is polypropylene having an Mw / Mg of less than 10 and Mw / Mn of less than 10. The commercially available product (a) is polypropylene PF-814 (manufactured by Montell).

The resin constituting the polyolefin foam layer is 1
Or a mixture of two or more. The polyolefin foam layer may contain a thermoplastic elastomer as long as the effects of the present invention are not significantly impaired.

The foaming agent used to form the foamed layer is preferably an inert substance such as water and carbon dioxide. In particular, when polypropylene is used as the resin constituting the foam layer, the use of carbon dioxide is preferred. By using such a foaming agent, the residual concentration of the organic compound having 3 to 4 carbon atoms in the laminated foam can be easily reduced to 100 ppm or less.

The polyolefin resin constituting the non-foamed layer is preferably a long-chain branched polypropylene or a long-chain branched polyolefin adhesive resin. Particularly, in order to obtain a laminated foam having excellent appearance, vacuum moldability, and the like, the long-chain branched polypropylene and the long-chain branched polyolefin adhesive resin have a branching degree index [A] of 0.20 ≦ [A] ≦ 0. .98
Preferably, 0.30 ≦ [A] ≦ 0.90
More preferably, 0.40 ≦ [A] ≦ 0.
It is particularly preferable to satisfy 80.

The branching index indicates the degree of long-chain branching, and is a numerical value defined by the following equation. Branching degree index [A] = [η] Br / [η] Lin Here, [η] Br is the intrinsic viscosity of the branched polypropylene, and [η] Lin is substantially the same in weight average molecular weight. It is the intrinsic viscosity of a tactic semicrystalline linear polypropylene.

Intrinsic viscosity, also known as limiting viscosity number, is in its most general sense a measure of the ability of a polymer molecule to enhance solution viscosity. The intrinsic viscosity depends on the size and shape of the dissolved polymer molecule. Thus, when comparing a non-linear polymer to a linear polymer of substantially the same weight average molecular weight, the intrinsic viscosity is a number that indicates the configuration of the non-linear polymer molecule. That is,
The ratio of the intrinsic viscosities described above is a measure of the degree of branching of the non-linear polymer, and was defined as a branching index. The method for measuring the intrinsic viscosity of long-chain branched polypropylene or long-chain branched polyolefin-based adhesive resin is described in Elliott et al. (J. App.
ly. Sci., 14, 2947-2963 (1970)]. The intrinsic viscosity can be measured at a temperature such as 135 ° C. by dissolving in tetralin or orthodichlorobenzene.

As the long-chain branched polypropylene for forming the non-foamed layer, the above-mentioned product of Montell is available as a commercial product and can be suitably used. The thickness of the non-foamed layer is not particularly limited as long as the smoothness of the surface, that is, the appearance is good, but it is 1 μm or more, and more preferably 10 μm or more.
It is suitable that it is at least 50 μm, more preferably at least 50 μm. The upper limit of the thickness is appropriately set according to the thickness of the entire multilayer polyolefin foam sheet, the application, and the like. If it is too thick, the properties of the foamed layer will not be sufficiently exhibited.

Here, the non-foamed layer is a layer having an expansion ratio of 1.0 times or more and 1.5 times or less, preferably 1.0 to 1.1 times. More than twice, preferably 2.5 to 40 times layers. If the expansion ratio is less than 2.5 times, the properties as a foam, specifically light weight, heat insulation, etc., will not be sufficient, and if it exceeds 40 times, the production will be difficult and the foam will break during vacuum forming. Can not be suppressed.
The expansion ratio can be adjusted by the amount of the foaming agent used, the pressure reduction after forming the multilayer foam sheet or after forming the laminated foam, and the like.

The polyolefin adhesive resin having a long chain branch, which is a preferable non-foaming layer constituting material in the present invention, includes 1) unsaturated carboxylic acid, unsaturated carboxylic anhydride, epoxy group-containing vinyl monomer, A copolymer of at least one monomer selected from the group consisting of a saturated carboxylic acid ester and a vinyl ester with an olefin monomer; 2) an acid-modified olefin polymer grafted with an unsaturated carboxylic acid or an acid anhydride thereof; Coalescence and the like are exemplified.

1) at least one monomer selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic anhydrides, epoxy group-containing vinyl monomers, unsaturated carboxylic acid esters and vinyl esters, and olefin monomers; Examples of the copolymer of ethylene- (meth)
Acrylic acid copolymer, ethylene- (meth) acrylic acid copolymer metal crosslinked product, ethylene-glycidyl methacrylate copolymer, ethylene-glycidyl methacrylate-vinyl acetate copolymer, ethylene-glycidyl methacrylate-methyl (meth) acrylate Copolymer, ethylene-
Examples thereof include (meth) acrylate copolymers, ethylene- (meth) acrylate-maleic anhydride copolymers, and ethylene-vinyl acetate copolymers.

Examples of the above 2) acid-modified olefin polymer grafted with an unsaturated carboxylic acid or an acid anhydride thereof include a maleic anhydride-grafted ethylene polymer and a maleic anhydride-grafted propylene polymer. Coalescence is exemplified.

The resin constituting the non-foamed layer may be one kind or a mixture of two or more kinds. The non-foamed layer may contain a thermoplastic elastomer as long as the effects of the present invention are not significantly impaired.

In a preferred embodiment, known additives are blended in the above-mentioned resin constituting the foamed layer and the resin constituting the non-foamed layer, and include an antioxidant, a light stabilizer, an ultraviolet absorber, an antifogging agent, and a plasticizer. Examples thereof include agents, antistatic agents, lubricants, coloring agents, fillers, nucleating agents, and other polymer compounds (described in “Separation and Analysis Techniques for Polymer Additives” (Japanese Science Information)). These addition amounts are within a range that does not impair the effects of the present invention.

The gas barrier resin film used for forming the gas barrier resin layer used in the present invention will be described. The resin used for the gas barrier film of the present invention is not particularly limited, but specific examples include the following.

Saponified polyvinyl esters such as polyvinyl alcohol; saponified ethylene-vinyl ester copolymers such as ethylene-vinyl alcohol copolymer; polyesters such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and polyhydroxybenzoic acid Resin; nylon-6, nylon-
6,6, meta-xylene diamine-adipic acid condensation polymer,
Polymethylmethacrylimide, diethylenetriamine-
Polyamide resins such as adipic acid copolymers and salts thereof;
Aramid resins; acrylic resins such as polymethyl methacrylate, polyacrylic acid, sodium polyacrylate, poly-2-hydroxyethyl acrylate, poly-2-hydroxyethyl methacrylate, polyacrylamide, ethylene-acrylic acid copolymers and salts thereof Resins; halogen-containing resins such as polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, and polytetrafluoroethylene; polycarbonate resins, polysulfone resins, polyether sulfone resins, polyether ether ketone resins, polyphenylene ether resins, polyphenylene oxide resins, Engineering plastic resins such as polyarylene sulfide resin, polymethylene oxide resin, and polyacetal resin. Further, a so-called modified resin obtained by graft-modifying, cross-linking or modifying the terminal of a molecular chain of these resins may be used.

The gas barrier resin film used in the present invention can be produced by a method of forming the above-mentioned resin or its composition from a molten state into a film, or by drying a solution as a liquid film.

As a method for forming a resin or a composition thereof from a molten state into a film, a common extrusion method such as T-die molding, inflation molding, injection molding, blow molding, stretch blow molding, etc. may be used. , An extrusion lamination method, a dry lamination method, and the like, and are not limited thereto. In a preferred embodiment, the film obtained by these methods is subjected to a stretching process generally performed, for example, uniaxial stretching, zone stretching, flat sequential stretching, flat simultaneous biaxial stretching, and tubular simultaneous stretching.

A resin or a composition thereof is dissolved in a solvent,
In order to obtain a film by a manufacturing method in which the obtained solution is formed into a liquid film and dried to produce a film, a resin containing a medium such as water or a composition thereof is coated on a release film to form a liquid film, and this is dried. A method of peeling off later or the like can be used.

As the above-mentioned coating method, direct gravure method, reverse gravure method, micro gravure method, two roll beat coating method, bottom feed method
Examples of the method include a roll coating method such as the reverse coating method and the like, a doctor knife method, a die coating method, a dip coating method, a bar coating method, and a coating method combining these methods.

The gas barrier resin film may be a single layer film composed of a single gas barrier resin layer, but is a multilayer film in which a gas barrier resin layer and another resin layer are laminated. It does not matter.

The other resin layer laminated with the gas barrier resin layer is not particularly limited, but is preferably a polyolefin resin forming the foamed layer, a polyolefin resin forming the non-foamed layer, and the polyolefin resin. A system adhesive resin is preferably used. The other resin layer laminated with the gas barrier resin layer may be a non-stretched resin layer or a stretched resin layer, but is preferably a non-stretched polyolefin resin layer. When a multilayer film composed of a gas barrier resin and another resin layer is used as described above, a laminated foam including the layer structure of the multilayer film can be obtained.

[0095]

EXAMPLES (Example) Foam layer constituent material: The intrinsic viscosity of the polymer in the first stage is 7.7 dl / g, and the intrinsic viscosity is 1.9 dl / g by the continuous continuous polymerization in the second stage. A polypropylene polymer was synthesized, and 0.1 parts by weight of calcium stearate, 0.05 parts by weight of Irganox 1010 (manufactured by Ciba Specialty Chemicals), and 100 parts by weight of this polymer powder, Sumilizer trade name 0.2 parts by weight of BHT (manufactured by Sumitomo Chemical Co., Ltd.) was added and mixed, and the mixture was melt-kneaded at 230 ° C. to obtain a pellet having an MFR of 12, which was used as a foam layer constituent material.

Non-foamed layer constituting material: Polypropylene having a long chain branch (PF814) manufactured by Montell Corporation was used.

Gas barrier resin film: saponified ethylene-vinyl acetate copolymer having an ethylene content of 44 mol% and a saponification degree of 98% or more (EP-E10 manufactured by Kuraray Co., Ltd.)
5A: MFR = 5.5) was applied to a gas barrier resin layer, polypropylene (Sumitomo Chemical Co., Ltd., polypropylene FL811)
5: MFR = 7) as the surface layer and acid-modified polypropylene (Admer QF551 manufactured by Mitsui Petrochemical Co., Ltd.).
7) is an adhesive layer, and the thickness configuration is (adhesive layer / barrier layer / adhesive layer / surface layer = 10/30/10/50 (unit: μm))
And coextruded into a film so that the thickness distribution of the coextruded film measured in the range of 25 cm ² Tmax /
A gas barrier resin film having a Tmin of 1.0 was produced.

(Extrusion Foaming Test) An apparatus (the configuration shown in FIG. 1) in which a 90 mmΦ circular die (7) was attached to a 50mmΦ twin screw extruder (3) and a 32mmΦ single screw extruder (5) was used. Propylene polymer 100 for foam layer
A raw material obtained by blending 1 part by weight of a nucleating agent (trade name: Hydrocellol, manufactured by Behringer Ingelheim Chemicals Co., Ltd.) with respect to parts by weight was put into a hopper of an extruder (3),
One part by weight of carbon dioxide gas was injected from the position where the melting was advanced, and the raw material and carbon dioxide gas were sufficiently kneaded and melted and sent to a die (7). The molten mixture for the foamed layer and the molten resin for the non-foamed layer fed from the extruder (5) are laminated in a die and co-extruded to form a cylindrical foamed sheet, which is placed immediately after the die. While expanding along the mandrel (9). Slits were made at two locations on the expanded cylindrical foam sheet with a cutter, and the cylinder was opened to form two flat foam sheets. A gas-barrier resin film was supplied between the two foamed sheets, and was laminated while being taken up by a take-off roller (11) to obtain a laminated foamed sheet (laminated foam).

(Evaluation of Vacuum Formability) The obtained laminated foam sheet was subjected to a far infrared heater at a surface temperature of 130 ° C. to 160 ° C.
And vacuum formed using a cylindrical female mold.

(Evaluation of Appearance) The ratio of the area where appearance defects such as dents and uneven thickness were observed with respect to the total surface area of the vacuum molded article (area of defective molded article appearance / total area of molded article) was determined. The higher the value of this ratio, the poorer the appearance, and the lower the value, the better the appearance.

The results of evaluation of the laminated foam sheet of the example are as follows.
It is as follows.

Laminated polypropylene foam sheet thickness: 1 m
m Thickness of non-foamed layer: 70 μm Thickness distribution of gas barrier resin layer (Tmax / Tmin):
1.0 Expansion ratio of foamed layer: 4 times Appearance evaluation result: 0.01 As described above, the appearance evaluation of the laminated foamed sheet of the present invention is excellent in that the ratio of the defective area of the molded article appearance / the total area of the molded article is small and small. Met.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a manufacturing apparatus and a method of manufacturing a laminated foam suitable for carrying out the present invention using a circular die.

FIG. 2 is a view showing another embodiment of a production apparatus and a production method of a laminated foam suitable for carrying out the present invention.

FIG. 3 is a view showing another embodiment of a production apparatus and a production method of a laminated foam suitable for carrying out the present invention.

FIG. 4 is a diagram showing another embodiment of a production apparatus and a production method of a laminated foam suitable for carrying out the present invention.

FIG. 5 is a diagram showing a cross-sectional shape of an example of a circular die.

FIG. 6 is a view showing another embodiment of a production apparatus and a production method of a laminated foam suitable for carrying out the present invention using a flat die.

FIG. 7 is a view showing another embodiment of a production apparatus and a production method of a laminated foam suitable for carrying out the present invention using a flat die.

FIG. 8 is a diagram showing another embodiment of a manufacturing apparatus and a method of manufacturing a laminated foam suitable for carrying out the present invention using two flat dies.

FIG. 9 is a view showing another embodiment of a manufacturing apparatus suitable for carrying out the present invention and a method of manufacturing a laminated foam provided with two multilayer foam sheet manufacturing apparatuses.

FIG. 10 is a longitudinal sectional side view showing another embodiment of the flat die.

[Explanation of symbols]

 Reference Signs List 3 first extruder 5 second extruder 6 foaming agent supply device 7 extrusion die 15 multilayer polyolefin foam sheet 23 gas barrier resin film supply device 36 gas barrier resin film

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) // B29K 23:00 B29K 23:00 105: 04 105: 04 105: 20 105: 20 B29L 9:00 B29L 9:00

Claims (12)

[Claims] 1. A method for producing a laminated foam comprising at least one polyolefin foam layer, at least one polyolefin non-foam layer, and at least one gas barrier resin layer, wherein the polyolefin foam layer At least one first extruder having a blowing agent supply device for extruding a constituent material and supplying a blowing agent to a cylinder, at least one second extruder for extruding the polyolefin non-foamed layer constituent material, and the polyolefin A gas barrier resin film having at least one extrusion die for forming a multi-layer polyolefin foam sheet by co-extruding a foam layer constituent material and the polyolefin non-foam layer constituent material, and a gas barrier resin film having at least one gas barrier resin layer is formed of the multilayer polyolefin foam. At least one gas-barrier tree supplied in a stackable manner on a sheet Using a manufacturing apparatus provided with a film supply device, the first extruder melts the polyolefin foam layer constituent resin material, and supplies the melted polyolefin foam layer constituent resin material and the blowing agent supply device. A melt kneading step of mixing a foaming agent with the polyolefin foam layer forming material to form a polyolefin foam layer forming material, a melting step of melting a polyolefin non-foaming layer forming material in the second extruder, and the polyolefin foam layer forming material and the A co-extrusion step of forming a multilayer polyolefin foam sheet by co-extruding a polyolefin non-foam layer constituent material in a molten state under atmospheric pressure to foam the polyolefin foam layer constituent material; and At least one gas barrier resin film supply device Like the gas barrier resin film supplying method for producing a multilayer foam which is characterized by having a lamination step of laminating said multilayer polyolefin foamed sheets and the gas barrier resin film. 2. The manufacturing apparatus includes one of the first extruder and the second extruder, and includes a circular die as the extrusion die.
A polyolefin foam layer forming material and a polyolefin non-foaming layer forming material are co-extruded in a tubular shape to form a multilayered polyolefin foamed sheet, and the tubular multilayered polyolefin foamed sheet is cut in two lengthwise directions. And providing an incision step to make two multi-layer polyolefin foam sheets, the laminating step supplies a gas barrier resin film between the two multi-layer polyolefin foam sheets,
The method for producing a laminated foam according to claim 1, wherein the two multilayer polyolefin foam sheets are laminated on both surfaces of the gas barrier resin film. 3. The manufacturing apparatus includes one of the first extruder and the second extruder, and includes a circular die as the extrusion die.
A polyolefin foam layer constituent material and a polyolefin non-foam layer constituent material are co-extruded in a tubular shape to form a multilayer polyolefin foam sheet. The tubular multilayer polyolefin foam sheet is cut at two locations in the length direction. 2
The multi-layer polyolefin foam sheet includes an incision step of forming a foamed sheet, the laminating step supplies a gas barrier resin film to at least one outer surface of the two multilayer polyolefin foam sheets, the gas barrier resin film and the two The method for producing a laminated foam according to claim 1, wherein a multilayer polyolefin foam sheet is laminated. 4. The manufacturing apparatus includes one of the first extruder and the second extruder, and includes a circular die as the extrusion die.
A multi-layer polyolefin foam sheet is formed by co-extruding a polyolefin foam layer constituent material and a polyolefin non-foam layer constituent material in a tubular shape, and the cylindrical multilayer polyolefin foam sheet is cut at one location in a longitudinal direction. The laminating step comprises supplying a gas barrier resin film to at least one surface of the cut multilayer polyolefin foam sheet, and laminating the gas barrier resin film and the multilayer polyolefin foam sheet. The method for producing a laminated foam according to claim 1. 5. The manufacturing apparatus includes one of the first extruder and the second extruder, and one flat die having two parallel extrusion openings as the extrusion die. In the co-extrusion step, a polyolefin foamed layer constituent material and a polyolefin non-foamed layer constituent material are supplied to the respective extrusion openings, and are co-extruded.
Forming a multi-layer polyolefin foam sheet, wherein the laminating step comprises supplying a gas barrier resin film between the two multi-layer polyolefin foam sheets and forming the gas barrier resin film and the two multi-layer polyolefin foam sheets. The method for producing a laminated foam according to claim 1, wherein the laminated foam is laminated with a sheet. 6. The manufacturing apparatus includes one of the first extruder and the second extruder, and one flat die having two extrusion openings parallel to each other as the extrusion die. In the co-extrusion step, a polyolefin foam layer constituent material and a polyolefin non-foam layer constituent material are supplied to the extrusion openings, respectively, and co-extruded to form two multi-layer polyolefin foam sheets. The step is characterized in that a gas barrier resin film is supplied to at least one surface outside the two multilayer polyolefin foam sheets, and the gas barrier resin film and the two multilayer polyolefin foam sheets are laminated. A method for producing a laminated foam according to claim 1. 7. The manufacturing apparatus includes one of the first extruder and the second extruder, and includes two flat dies having one extrusion opening as the extrusion dies. The dies are set so that the extrusion openings are parallel to each other. In the co-extrusion step, the polyolefin foam layer forming material and the polyolefin non-foaming layer forming material are supplied to two flat dies, respectively, and co-extruded. Forming two multi-layered polyolefin foamed sheets, and in the laminating step, supplying a gas barrier resin film between the two multi-layered polyolefin foamed sheets, and forming the gas barrier resin film and the two multi-layered polyolefin foamed sheets. The method for producing a laminated foam according to claim 1, wherein the method is to laminate a polyolefin foam sheet. 8. The manufacturing apparatus includes one of the first extruder and the second extruder, and includes two flat dies having one extrusion opening as the extrusion dies. The extrusion openings are installed so as to be parallel to each other. In the co-extrusion step, the polyolefin foamed layer constituent material and the polyolefin non-foamed layer constituent material are supplied to two flat dies, respectively, and co-extruded. Forming a multi-layer polyolefin foam sheet, wherein the laminating step comprises supplying a gas barrier resin film to at least one outer surface of the two multi-layer polyolefin foam sheets; The method for producing a laminated foam according to claim 1, wherein the multi-layer polyolefin foam sheet is laminated. 9. The manufacturing apparatus includes two first extruders and two second extruders, and includes two dies selected from a flat die and a circular die as the extrusion dies. The first extruder, the second
An extruder, and two multi-layer polyolefin foam sheet manufacturing apparatuses in which each one of the extrusion dies is disposed, wherein the co-extrusion step includes forming a polyolefin foam layer constituent material and a polyolefin non-foam layer constituent material into The multilayer polyolefin foam sheet is supplied to each multilayer polyolefin foam sheet manufacturing apparatus and co-extruded to form two multilayer polyolefin foam sheets. In the laminating step, a gas barrier resin film is placed between the two multilayer polyolefin foam sheets. Supply,
2. The method according to claim 1, wherein the layers are laminated.
3. The method for producing a laminated foam according to item 1. 10. The manufacturing apparatus includes two first extruders and two second extruders, and includes two dies selected from flat dies and circular dies as the extrusion dies. An extruder, the second extruder, and the extrusion die each include two multi-layer polyolefin foam sheet manufacturing apparatuses in which one extruder is provided. The co-extrusion step includes a polyolefin foam layer constituent material and a polyolefin non-woven sheet. A foam layer constituent material is supplied to each of the multilayer polyolefin foam sheet manufacturing apparatuses, and is co-extruded into two multilayer polyolefin foam sheets, and the laminating step includes at least one of the two multilayer polyolefin foam sheets. A gas barrier resin film is supplied to one side, and the gas barrier resin film and the two multi-layered poly films are provided. Method for producing a laminated foam according to claim 1, characterized in that for stacking the olefin foam sheet. 11. The production of a laminated foam according to claim 1, further comprising a decompression step of passing the multilayer polyolefin foam sheet or the laminated foam through a decompression chamber to increase the expansion ratio of a foam layer. Method. 12. The multilayer polyolefin foamed sheet before at least one of the laminating step and the pressure reducing step,
The method for producing a laminated foam according to any one of claims 1 to 11, further comprising a preheating step of preheating at least one of the laminated foams.