JP2011194697A - Method and device of manufacturing multilayer extrusion-foamed molding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a multilayer extrusion-foamed molding capable of suppressing the turbulence of the layer structure of each of layers constituting a molding.SOLUTION: The method includes a first step for obtaining a laminated molten resin C merging a foaming agent-containing molten resin A and a foaming agent-free molten resin B in the thickness direction at high pressure, a second step for obtaining divided laminated molten resins D1, D2 by dividing and separating the laminated molten resin C at the center in the width direction, a third step for separating the divided laminated molten resins D1, D2 in the thickness direction, a fourth step for fitting the position in such a manner that the divided laminated molten resins D1, D2 are vertically aligned with each other in a separated state, and a fifth step for obtaining a doubling laminated molten resin E by merging the vertical divided laminated molten resins D1, D2. A straightening step for reducing the right and left flow rate difference by holding a positional relationship in right and left direction positions fitted in such a manner that the divided laminated molten resins D1, D2 are vertically aligned with each other, and moving to the downstream side by a predetermined length as in their separated states is provided between the fourth step and the fifth step.

Description

  The present invention relates to a multilayer extrusion foamed article formed by laminating a foamed layer and a non-foamed layer suitably used for construction, automobiles, civil engineering and the like.

Conventionally, with regard to multilayer extrusion foaming obtained by laminating a foamed layer and a non-foamed layer, studies have been made mainly on film and sheet shapes using a polypropylene resin (see, for example, Patent Documents 1 to 4).
Also, as a method of increasing the number of layers without complicating the structure of the laminating equipment such as feed blocks and multi-manifolds and increasing the size, a molten resin containing a foaming agent and a molten resin not containing a foaming agent are used in the thickness direction. There has been proposed a lamination doubling method in which the molten resin is divided into two in the width direction after being merged, and each of the two divided molten resins is compressed in the thickness direction and then merged up and down in the thickness direction (for example, Non-Patent Document 1). The number of layers can be increased efficiently by using such a method of doubling the number of layers for multilayering (see, for example, Non-Patent Document 1 and Patent Documents 5 and 6).

Japanese Patent Laid-Open No. 10-748 JP-T-4-505594 Japanese Examined Patent Publication No. 7-98349 WO08 / 008875 pamphlet Japanese Examined Patent Publication No. 54-23025 JP-A-4-278323

ADITYA P. RANADE, ANNE HILTNER AND ERIC BAER, "Structure-Property Relationships in Coextruded Foam / Film Microlayers", JOURNAL OF CELLULAR PLASTICS, November 2004, Vol.40, pp.497-507

In the multi-layering by the above-described lamination doubling method, when the molten resin layers divided into two in the thickness direction are merged up and down, the resin pressure, flow rate, etc. of the upper and lower molten resin layers are different. There is a concern that the lamination state may be disturbed, and there is a concern that the lamination state disturbance may be further deteriorated through the super multi-layer process.
In particular, when a multilayer extrusion foamed molded product is used for a heat insulating material application, if each layer constituting the molded product is laminated obliquely in the thickness direction as a result of the disturbance of the laminated state as described above, compared to the foamed layer In addition, since heat is transferred through a non-foamed layer having a high thermal conductivity, there is a problem in that the desired performance cannot be obtained because the heat insulation performance is significantly reduced.

  Therefore, in view of the above-described situation, the present invention intends to provide a manufacturing method and a manufacturing apparatus for a multilayer extrusion foamed molded body that can suppress the disorder of the layer structure of each layer constituting the molded body. is there.

The inventor of the present application pays attention to the disorder of the lamination state when the molten resin divided into two in the thickness direction is merged up and down in the multi-layering by the above-described double layering method, and performs experiments and three-dimensional flow analysis simulations. As a result, due to the difference in flow rate in the thickness direction of the molten resin layer immediately after merging up and down, the foamed layer and the non-foamed layer constituting the obtained multilayer extruded foamed product are laminated obliquely in the thickness direction. As a result, the present invention was completed.
That is, in order to solve the above-mentioned problem, the method for producing a multilayer extrusion foamed molded body according to the present invention continuously molds a heat-plasticized molten resin into a constant cross-sectional shape with a mold while extruding it in the flow direction. In a method for producing an extrusion foamed molded article, at least one molten resin containing a foaming agent and at least one molten resin not containing a foaming agent are merged in a vertical direction that is a thickness direction under high pressure to obtain a laminated molten resin. The first step, the second step of dividing the laminated molten resin at the center in the left-right direction that is the width direction and separating the laminated molten resin in the left-right direction to obtain two divided laminated molten resins on the left and right, and the two divided laminated molten resins on the left and right, A third step in which the lower end of one side is separated from the upper end of the other side in the up-down direction, and the two divided laminated molten resins are moved in the left-right direction so that the two divided laminated molten resins The two divided laminated molten resins are aligned in a vertical direction until the center in the right direction overlaps vertically so as to be located in the vertical plane parallel to the flow direction through the horizontal center of the laminated molten resin. A method for producing a multilayer extrusion foamed molded article, comprising: a fourth step of aligning the positions as described above; and a fifth step of merging these two upper and lower divided laminated molten resins in the vertical direction to obtain a doubled laminated molten resin, Between the fourth step and the fifth step, the two divided laminated molten resins are in a state in which the two divided laminated molten resins are separated while maintaining the positional relationship in the left-right direction aligned so that the two divided laminated molten resins are aligned vertically. A rectification process is provided to reduce the difference between the left and right flow velocities by moving to a downstream side with a predetermined length.

According to such a configuration, the difference between the left and right flow velocities caused by bringing the divided laminated molten resin close to the left and right in the fourth step and aligning them so as to be aligned in the vertical direction is divided into the upper and lower divided laminated layers. It can be reduced by a rectification step provided before the molten resin merges in the fifth step.
Therefore, in the fifth step, the molten resin having a low flow velocity and the molten resin having a high flow velocity do not merge vertically at the left end portion and the right end portion of the flow path, and the left end portion and the right end portion of the flow path of the doubling laminated molten resin Since the flow rate in the thickness direction does not reverse, the foamed layer and the non-foamed layer constituting the manufactured multilayer extrusion foamed molded product are not laminated obliquely in the thickness direction, and the non-foamed layer becomes substantially horizontal. Therefore, the expected heat insulation performance can be ensured.

Here, it is preferable to provide a width expansion step for expanding the width twice without changing the cross-sectional area of the laminated molten resin between the first step and the second step. The sectional area of each of the divided laminated molten resins is changed between the step and the third step, between the third step and the fourth step, or between the fourth step and the fifth step. A width expanding step for expanding the width twice may be provided, and after the fifth step, a width expanding step for expanding the width twice without changing the cross-sectional area of the doubled laminated molten resin is provided. May be.
According to such a configuration, before and after the stack doubling step, that is, the downstream channel cross-sectional area of the first step and the downstream channel cross-sectional area of the fifth step (the width expanding step after the fifth step). This is convenient when multi-layering the layer doubling step, and the layer doubling step is simplified with a simple structure. A multi-stage flow path can be configured to form a multilayered product.

  In order to solve the above-mentioned problems, an apparatus for producing a multilayer extrusion foamed molded product according to the present invention is an extrusion foaming method in which a heat-plasticized molten resin is extruded in the flow direction and arranged in a mold with a constant cross-sectional shape and continuously molded. In a molding body manufacturing apparatus, a foaming extruder that pressurizes and supplies a molten resin containing a foaming agent, a non-foaming extruder that pressurizes and supplies a molten resin that does not contain a foaming agent, and supply from these extruders A laminated apparatus that combines at least one molten resin containing a blowing agent and at least one molten resin not containing a blowing agent in a thickness direction to form a laminated molten resin, the width of the laminated molten resin A doubling laminated molten resin that is divided into two divided laminated molten resins by being divided at the center in the left-right direction that is the direction, and these divided laminated molten resins are merged so as to overlap each other vertically; And a multi-layer extrusion foamed molded article manufacturing apparatus comprising a molding die for increasing the pressure by opening the doubled laminated molten resin under atmospheric pressure and evaporating the foaming agent. The left and right divided laminated molten resins are separated in the vertical direction so that one lower end is higher than the other upper end, and the two divided laminated molten resins are moved in the left and right directions so that the two divided laminated resins are In a state where these two divided laminated molten resins are separated until the position where the center of the molten resin overlaps vertically so that the center of the molten resin passes through the center of the laminated molten resin in the horizontal direction and is parallel to the flow direction. A state where the two divided laminated molten resins are separated while maintaining the positional relationship in the left-right direction so that the two divided laminated molten resins are aligned vertically after the positions are aligned so as to be aligned vertically Mom downstream moving a predetermined length includes a rectifier circuit, and wherein said causing the split multilayer molten resin merges as superimposed vertically after reducing the flow rate difference between the right and left by the rectification circuit.

According to such a configuration, the difference between the left and right flow velocities caused by bringing the divided laminated molten resin closer to the left and right directions by the lamination doubling device and aligning them so as to be aligned vertically in the separated state is It can be reduced by a rectifying path provided before the divided laminated molten resin joins.
Therefore, the molten resin having a low flow velocity and the molten resin having a high flow velocity do not merge vertically at the left end portion and the right end portion of the flow path where the upper and lower divided laminated molten resins merge in the lamination doubling apparatus. Since the flow rate in the thickness direction does not reverse at the left end and right end of the flow path of the molten resin, the foamed layer and the non-foamed layer constituting the manufactured multilayer extruded foamed product are laminated obliquely in the thickness direction. In addition, since the non-foamed layer becomes substantially horizontal, the desired heat insulating performance can be ensured.

  As described above, according to the method and apparatus for producing a multilayer extruded foam molded body according to the present invention, it is possible to suppress the disorder of the layer structure of each layer constituting the molded body. Since the foamed layer and the non-foamed layer constituting the body are not laminated obliquely in the thickness direction, the non-foamed layer becomes substantially horizontal, so that a remarkable effect of ensuring the desired heat insulation performance can be obtained.

It is the schematic which shows the structure of the manufacturing apparatus of the multilayer extrusion foaming molding which concerns on embodiment of this invention. It is sectional drawing which shows the example of the multilayer extrusion foaming molding manufactured by the manufacturing method and manufacturing apparatus of the multilayer extrusion foaming molding which concern on embodiment of this invention. The process explanatory drawing of the manufacturing method of the multilayer extrusion foaming molding which concerns on embodiment of this invention is shown with the schematic diagram of a flow-path cross section, and shows a width expansion process between a 1st process and a 2nd process. The case where it provides is shown. The process explanatory drawing is shown together with the schematic diagram of the cross section of the flow path, and shows the case where the width expansion process is provided between the second process and the third process. The process explanatory drawing is shown together with the schematic diagram of the cross section of the flow path, and shows the case where the width expansion process is provided between the third process and the fourth process. The process explanatory drawing is shown together with the schematic diagram of the cross section of the flow path, and shows the case where the width expansion process is provided between the fourth process and the fifth process. The process explanatory drawing is shown together with the schematic diagram of the cross section of the flow path, and shows the case where the width expansion process is provided between the fifth process and the sixth process. In the process shown in FIG. 3, (a) is the fifth process for the case where the length L of the rectifying path is 30 mm (Example 1), 50 mm (Example 2), 80 mm (Example 3), and 0 mm (Comparative Example). FIG. 6B is a diagram showing a simulation result of flow velocity distribution in each part in the width direction immediately after joining, and (b) is a schematic diagram showing a flow path of the stacking doubler. In the process shown in FIG. 6, when the length L of the rectifying path is 30 mm (Example 4), it is a figure which shows the simulation result of the flow velocity distribution of each part of the width direction immediately after merging in a 5th process, (b) is a lamination | stacking. It is a schematic diagram which shows the flow path of a doubling apparatus. In the process shown in FIG. 7, in the case where the length L of the rectifying path is 30 mm (Example 5), it is a diagram showing a simulation result of the flow velocity distribution of each part in the width direction immediately after merging in the fifth process. It is a schematic diagram which shows the flow path of a doubling apparatus.

  In the following, the left side and the right side refer to the downstream side of the flow direction of the molten resin (the direction from the upstream side to the downstream side, the extrusion direction, see arrow F in the figure).

  As shown in FIG. 1, the apparatus for producing a multilayer extrusion foamed molded article according to an embodiment of the present invention has a constant cross section with a mold while extruding a heat-plasticized molten resin in a flow direction (see arrow F in the figure). Non-foaming extruder 1 that pressurizes and supplies molten resin containing a foaming agent and pressurizes and supplies molten resin that does not contain a foaming agent. Machine 2 and at least one molten resin containing a foaming agent and at least one molten resin not containing a foaming agent supplied from these extruders 1 and 2 are merged in the vertical direction, which is the thickness direction, and laminated and melted. Laminating apparatus 3 that is a resin, for example, a feed block, the laminated molten resin is divided into two divided laminated molten resins by dividing the laminated molten resin at the center in the left-right direction that is the width direction, and these divided laminated molten resins are superposed vertically A doubling and laminating apparatus 4 for flowing a doubling laminated molten resin, a molding die 5 for increasing the magnification by releasing the doubling laminated molten resin under atmospheric pressure and vaporizing a foaming agent, and a foamed molded body The molding machine 6 is cooled to a final shape while being restrained in the vertical direction.

Here, if the foaming agent in the molten resin containing the foaming agent foams in the flow path through which it is released under atmospheric pressure, cell enlargement and low closed cell ratio occur in the foamed layer. The resulting multilayer extrusion foamed molded product tends not to exhibit the effect of reducing the thermal conductivity expected by multilayering.
Therefore, a flow through which the foaming agent in the molten resin containing the foaming agent is released under atmospheric pressure by joining the molten resin containing the foaming agent and the molten resin not containing the foaming agent under high pressure. It is necessary to suppress foaming in the road.
FIG. 2 is a cross-sectional view showing an example of the multilayer extrusion foam molded body 7 manufactured by such a multilayer extrusion foam molded body manufacturing apparatus, and a rectifying process in the lamination doubling process of FIGS. 3 to 7 described later. That is, the two non-foamed layers 9 and 9 have a thickness due to the rectification effect by the rectification path 10 (see FIGS. 8B, 9B, and 10B) of the stacking doubler 4. It is laminated | stacked between the upper and lower foam layers 8 and 8 substantially horizontally (it is substantially parallel to the surface of the multilayer extrusion foaming molding 7), without being laminated | stacked diagonally in a direction.

As shown in FIG. 2, the multilayer extruded foam 7 has a structure in which the foamed layers 8,... Are laminated in the thickness direction of the extruded foam 7 via the non-foamed layers 9. Is preferred. This is because, in the structure in which the foam layers 8 are laminated on the upper and lower surfaces of the non-foam layer 9, the thickness of the non-foam layer 9 is larger than the thickness of the cells constituting the foam layer 8, thereby This is because the effect of reducing the thermal conductivity due to the suppression works effectively.
In addition, in the structure where the layer laminated on the top and bottom is a structure in which the foam layer is laminated only on one side of the non-foam layer, such as non-foam layer / foam layer / non-foam layer, There is a tendency that the effect of reducing the thermal conductivity is not sufficiently exhibited.
Also, the structure of the multilayer extrusion foamed molded body 7 is such that the non-foamed layer has a layered structure such as foamed layer / non-foamed layer / foamed layer / non-foamed layer / foamed layer as shown in FIG. More preferably, there are multiple layers. This is because by providing a plurality of non-foamed layers 9 in the thickness direction of the extruded foamed molded body 7, an excellent effect of reducing the thermal conductivity that cannot be obtained with one non-foamed layer 9 appears.

Next, the manufacturing method of the multilayer extrusion foaming molding which concerns on embodiment of this invention is demonstrated using the process explanatory drawing shown in FIGS. 3-7, the first step is a step by the extruders 1 and 2 and the laminating apparatus 3 in FIG. 1, and the second to fifth steps are steps by the laminating doubler 4 in FIG. 1 (lamination 2). The sixth step shows a step by the molding die 5 and the molding machine 6 of FIG.
Moreover, the schematic diagram of the flow-path cross section in FIGS. 3-7 has shown the cross section seen from the downstream.

First, the process shown in FIG. 3 will be described.
(First step)
The first step is shown as an example of at least one molten resin containing no foaming agent, and two upper and lower layers of molten resin A, A containing a foaming agent as an example of at least one molten resin containing a foaming agent. In a step of obtaining a laminated molten resin C in which the molten resin B containing no foaming agent is merged in the vertical direction which is the thickness direction under high pressure, and the molten resin B is interposed between the upper and lower molten resins A, A is there.
(Width expansion process)
The width expansion step is a step of expanding in the left-right direction (for example, β1 / α1 = 2) without changing the cross-sectional area of the laminated molten resin C laminated in the first step.
(Second step)
The second step is a step in which the laminated molten resin C expanded in the width expanding step is divided at the center in the left-right direction and separated in the left-right direction to obtain two left and right divided laminated molten resins D1, D2.
(Third step)
In the third step, the divided laminated molten resins D1 and D2 divided in the second step are arranged so that one lower end is above the other upper end (in the example of FIG. 3, the lower end of D1 is higher than the upper end of D2 This is a step of separating the vertical direction.
(4th process)
In the fourth step, the divided laminated molten resins D1 and D2 separated vertically in the third step are made to approach in the left-right direction, and the center in the left-right direction of these two divided laminated molten resins D1, D2 is the left-right direction of the laminated molten resin C. This is a step of aligning the divided laminated molten resins D1 and D2 so as to be aligned in the vertical direction up to a position overlapping vertically so as to be located in a vertical plane passing through the center and parallel to the flow direction F.
(Rectifying process)
The flow straightening process is downstream in the state where the two divided laminated molten resins D1 and D2 are separated while maintaining the positional relationship in the left-right direction aligned so that the divided laminated molten resins D1 and D2 are aligned vertically in the fourth process. This is a step of reducing the difference in the flow velocity distribution in the left-right direction by moving a predetermined length L (see FIG. 8B) to the side.
(5th process)
The fifth step is a step of obtaining the doubled laminated molten resin E by joining the two upper and lower divided laminated molten resins D1 and D2 in which the difference in flow velocity distribution in the left and right direction is reduced in the rectifying step in the vertical direction.
(Sixth step)
In the sixth step, the doubled laminated molten resin E obtained in the fifth step is opened at atmospheric pressure to evaporate the foaming agent, and then the foamed molded product is taken up and cooled while being restrained in the vertical direction. This is a step of making the final shape (see, for example, FIG. 2).

Next, the steps shown in FIGS. 4 to 7 will be described.
In the steps shown in FIGS. 4 to 7, the position of the step of expanding the width (the order of performing the width expanding step in the entire step) is different from that of the step shown in FIG. 3.
That is, the process shown in FIG. 4 is between the second process and the third process, the process shown in FIG. 5 is between the third process and the fourth process, and the process shown in FIG. 6 is the rectifying process and the fifth process. In the process shown in FIG. 7, a width expansion process is provided between the fifth process and the sixth process.
In the steps shown in FIGS. 4 to 6, the divided laminated molten resins D1 and D2 are expanded in the left-right direction without changing their cross-sectional areas (for example, β2 / α2 = 2) by the width expanding step. In the step shown in FIG. 7, the doubled laminated molten resin E is expanded in the left-right direction (for example, β2 / α2 = 2) without changing the cross-sectional area by the width expansion step.
In addition, you may provide a width expansion process between a 4th process and a rectification | straightening process.

  Here, by setting β1 / α1 = 2 as in the step shown in FIG. 3, or by setting β2 / α2 = 2 as in the steps shown in FIGS. Before and after, that is, the cross-sectional area of the downstream side of the first step and the cross-sectional area of the downstream side of the fifth step (if a width-enlarging step is provided after the fifth step, (Area) is the same, it is convenient when multi-layering the multi-layer stacking process, and a multi-layered flow path of the multi-layer stacking process is configured with a simple structure to form a multilayered product. Can do.

Also, as in the steps shown in FIGS. 3 to 7, the two divided laminated molten resins D <b> 1 and D <b> 2 are aligned vertically between the fourth step and the fifth step, that is, in the fourth step. After that, before the divided laminated molten resins D1 and D2 merge in the vertical direction in the fifth step, the two divided laminated molten resins D1 and D2 remain separated in the fourth step while maintaining the positional relationship in the left-right direction. By moving a predetermined length L to the downstream side (for example, see FIG. 8B, FIG. 9B and FIG. 10B), the left and right flow velocity difference (equal distance from the center in the left-right direction) Since the rectification process (for example, refer to rectification path 10 of Drawing 8 (b), Drawing 9 (b), and Drawing 10 (b)) which reduces the flow velocity difference of the downstream direction in the done position is provided, the 5th process The difference in flow velocity in the thickness direction at each part in the left and right direction of the doubled laminated molten resin E immediately after merging is reduced. .
Therefore, in the method for producing a multilayer extrusion foamed molded article of the present invention, a rectifying step for reducing the difference in flow velocity distribution in the left-right direction is provided before the divided laminated molten resins D1, D2 are joined in the thickness direction in the fifth step. Due to the rectifying effect, the produced multi-layer extrusion foamed molded product has non-foamed layers 9 and 9 sandwiched between upper and lower foam layers 8 and 8, for example, a multi-layer extruded foam molded product 7 shown in FIG. 2. The layers are laminated substantially horizontally without being obliquely laminated in the thickness direction.

On the other hand, when the rectifying process is not provided, the doubling lamination melting immediately after merging in the fifth process due to the difference in flow rate between the left and right of the two divided lamination molten resins D1 and D2 merged in the thickness direction. Since a difference in flow velocity occurs in the thickness direction of the resin E, the foamed layer and the non-foamed layer constituting the manufactured multilayer extrusion foamed molded body are laminated obliquely in the thickness direction.
This is because, in the method for doubling the lamination as shown in FIGS. 3 to 7, in the fourth step, the divided laminated molten resins D1 and D2 are moved close to each other in the left-right direction so that they are aligned in the vertical direction. Therefore, in the upper divided laminated molten resin D1, (right end channel length D1a)> (left end channel length D1b), and in lower divided laminated molten resin D2, (right end channel length). D2a) <(left end flow path length D2b), and due to the pipe resistance, the flow velocity at the right end is slower than the flow velocity at the left end in the upper divided laminated molten resin D1, and the left end in the lower divided laminated molten resin D2 This is due to the difference between the left and right flow rates.

  That is, when the upper divided laminated molten resin D1 and the lower divided laminated molten resin D2 are compared, at the left end portion of the flow path, (the flow velocity of the upper divided laminated molten resin D1)> (lower divided laminated molten resin) D2 flow velocity), and at the right end of the flow path, (the flow velocity of the upper divided laminated molten resin D1) <(the flow velocity of the lower divided laminated molten resin D2). In the fifth step, the molten resin having a low flow velocity and the molten resin having a high flow velocity merge vertically in the left and right sides of the flow path, and in the doubled laminated molten resin E thus merged, the thickness direction on the left and right sides of the flow path Since the direction of the flow rate of the material is reversed, the foamed layer and the non-foamed layer constituting the manufactured multilayer extrusion foamed molded product are laminated obliquely in the thickness direction.

In this way, the phenomenon in which the foamed layer and the non-foamed layer constituting the molded body are obliquely laminated in the thickness direction in the multilayer extrusion foamed molded article is the thickness direction in the right and left of the doubled laminated molten resin E immediately after joining in the fifth step. In order to eliminate this, the average flow velocity in the thickness direction of the doubling laminated molten resin E in each part in the left-right direction immediately after merging ((maximum value of flow velocity in the thickness direction + thickness direction) If the ratio of the flow rate difference in the thickness direction (maximum value of the flow rate in the thickness direction−the minimum value of the flow rate in the thickness direction) to the minimum flow velocity) / 2) (flow rate difference in the thickness direction / average flow velocity in the thickness direction) is reduced. Good.
The ratio (difference in flow rate in the thickness direction / average flow rate in the thickness direction) is preferably 0.3 or less, more preferably 0.2 or less, and most preferably 0.1 or less.

Further, by joining the molten resin A containing at least one layer of foaming agent and the molten resin B not containing at least one layer of foaming agent in the thickness direction, the effect of reducing the thermal conductivity expected by multilayering can be obtained. A structure that is easy to express can be obtained. This is because the thermal conductivity of the heat insulating material is measured in the thickness direction of the heat insulating material as defined in JIS A9511, and the presence of multiple non-foamed layers in the thickness direction suppresses radiant heat transfer between the foam layers. This is because an effect is expected, and an effective gas barrier effect is expected by increasing the area of the non-foamed layer covering the foamed layer.
For this reason, the multilayer extrusion foaming molding obtained by making the molten resin A containing a foaming agent and the molten resin B not containing a foaming agent join in the thickness direction becomes a thing with favorable heat insulation with low heat conductivity. On the other hand, when combined in the left-right direction, the resulting multilayer extruded foamed product has a high thermal conductivity because it conducts heat in a non-foamed layer having a higher thermal conductivity than the foamed layer (acts as a thermal bridge). It tends to be high and inferior in heat insulation performance.

In the case where the rectifying step is not provided as in the present invention, the foamed layer and the non-foamed layer constituting the molded body are laminated obliquely in the thickness direction as described above. In the same way as the multilayer extrusion foamed product obtained when merging in the direction, heat transfer is conducted in the non-foamed layer, which has a higher thermal conductivity than the foamed layer (it acts as a thermal bridge), resulting in high thermal conductivity and heat insulation There is a tendency to be inferior in performance.
Moreover, the meaning of using the co-extrusion foaming in which the molten resin A containing the foaming agent and the molten resin B not containing the foaming agent are merged and opened to atmospheric pressure is in addition to economic advantages, This is because high heat insulation is expected by the non-foamed layer suppressing the intrusion of air into the foamed layer cell.

The foamed layer constituting the multilayer extruded foamed product obtained by the method for producing a multilayer extruded foamed product of the present invention is a foamed structure in which a plurality of bubbles are joined together by a foam wall (wall) and a foam wall joint (struts). A layer having The shape is not particularly limited, and examples thereof include a film shape, a sheet shape, and a board shape. Among these, a sheet shape and a board can be obtained because it easily exhibits heat insulation performance and can impart lightness to an extruded foam molded body. Shape is preferred.
The density of the foamed layer is preferably 500 kg / m ³ or less, although it depends on the density of the extrusion-molded molded article.
The foam layer has a bubble diameter less than 1.2 times the average bubble diameter, small bubbles with a bubble diameter of 0.25 mm or less, and large bubbles with a bubble diameter greater than 1.2 times the average bubble diameter. Although it is comprised, you may have a characteristic bubble structure mixed in the shape of a sea island. By having such a characteristic cell structure, it is possible to reduce the density of the obtained molded body, and it is possible to obtain a foam molded body having excellent heat insulation and moldability. Here, the small bubbles mainly contribute to the improvement of the heat insulating performance, and the large bubbles mainly contribute to the reduction in density and the improvement of moldability.

In addition, even in a foamed molded article composed only of bubbles having a normal uniform bubble diameter, it is possible to improve the heat insulation performance to some extent by reducing the bubble diameter. However, in the case of foamed molded products consisting only of bubbles having a uniform cell diameter, if the cell diameter is reduced, more resin is required to obtain a predetermined thickness, resulting in higher density, resulting in heat insulation performance. The improvement effect tends to decrease. In addition, the moldability tends to decrease, for example, the pressure during extrusion increases and the discharge amount decreases.
On the other hand, the characteristic bubble structure in which small bubbles and large bubbles are mixed in a sea-island shape improves the heat insulation performance, and the foam layer obtained by the large bubbles has a low density and a high expansion rate in the thickness direction. It becomes possible to obtain a molded body.
Regarding the relationship between the bubble sizes of small bubbles and large bubbles, the small bubbles are less than 1.2 times the average bubble size, the average bubble size of the small bubbles is 0.25 mm or less, and the average bubble size of the large bubbles is If it is 1.2 times or more of an average bubble diameter, it will not specifically limit.

  In the foam layer, there is no absence of bubbles located between the bubble diameters of small bubbles and large bubbles, but when the bubbles increase noticeably, it becomes difficult to distinguish between small bubbles and large bubbles, Since the cell structure becomes a cell structure in which different cell diameters are continuously present and does not have the characteristic cell structure in a sea-island shape, the balance between heat insulation performance and moldability tends to be lost.

The ratio of the total area of small bubbles (occupied area ratio per unit cross-sectional area) in the cross section of the foamed layer located in the thickness direction center of the multilayer extruded foam molded body is preferably 5 to 95%, and 10 to 90%. Is more preferable, 20 to 80% is more preferable, and 25 to 70% is particularly preferable. When the ratio of the total area of the small bubbles in the cross section of the foam layer is 5 to 95%, a good extruded foam molded body excellent in heat insulation and moldability can be obtained.
As a method for producing a foam layer having a characteristic cell structure composed of small bubbles and large bubbles, a physical foaming agent and water may be used in combination as a foaming agent.

The amount of water used as the foaming agent is 0.1 to 5. with respect to 100 parts by weight of the thermoplastic resin constituting the foamed layer, from the viewpoint of easy generation of small bubbles and large bubbles and processability. 0 parts by weight is preferable, 0.2 to 4.0 parts by weight is more preferable, and 0.3 to 3.0 parts by weight is particularly preferable.
The amount of water added is preferably 1 to 80% by weight, more preferably 2 to 70% by weight, and particularly preferably 3 to 60% by weight based on the total amount of the foamed layer agent.
When the amount of water added is 0.1 to 5.0 parts by weight with respect to 100 parts by weight of the thermoplastic resin constituting the foamed layer, and 1 to 80% by weight with respect to the total amount of the foaming agent is obtained, The resulting foamed layer can easily have a characteristic cell structure composed of small cells and large cells, and as a result, the resulting multilayer extrusion foamed molded product is excellent in lightness, heat insulation and moldability.

  In producing a foam layer with a characteristic cell structure consisting of small bubbles and large cells, it is important how water that is incompatible with the thermoplastic resin constituting the foam layer is uniformly dispersed in the molten resin. It becomes. As the method, water-absorbing or water-swelling layered silicates such as smectite and swellable fluoromica in a thermoplastic resin or organically treated products thereof, water-absorbing polymers, AEROSIL manufactured by Nippon Aerosil Co., Ltd., etc. One or more kinds of anhydrous silica having a silanol group and the like (in the present specification, these substances are collectively referred to as “water-absorbing substances”) can be mentioned. Thereby, the dispersed state of small bubbles and large bubbles in the foamed layer is stabilized, and the moldability, productivity and heat insulation performance of the resulting multilayer extrusion foamed molded product can be further improved.

  The amount of the water-absorbing substance used when the foamed layer is produced is appropriately adjusted depending on the amount of water added, etc., but is generally 0 with respect to 100 parts by weight of the thermoplastic resin constituting the foamed layer. 0.1 to 10 parts by weight is preferable, 0.2 to 8 parts by weight is more preferable, and 0.3 to 7 parts by weight is particularly preferable. When the water-absorbing substance is added in an amount of 0.1 to 10 parts by weight, water is well dispersed in the extruder, and a foamed layer having a good cell structure free from bubble unevenness and voids is obtained. It is possible to obtain an extrusion foamed molded article having good heat insulation performance without any problems.

The layered silicate used in manufacturing the foamed layer is composed of a tetrahedral sheet mainly composed of silicon oxide and an octahedral sheet mainly composed of a metal hydroxide, and the tetrahedral sheet and the octahedron. Sheets form unit layers and exist as primary particles and primary particle aggregates (secondary particles) that have a single unit layer structure or a structure in which a plurality of unit layers are laminated with cations between layers. To do. Specific examples of the layered silicate include smectite clay and swellable mica.
The smectite clay is represented by the following general formula (I)
X _{0.2 to 0.6} Y _{2 to 3} Z ₄ O ₁₀ (OH) ₂ .nH ₂ O... General formula (I)
(However, X is at least one selected from the group consisting of K, Na, 1 / 2Ca, and 1 / 2Mg, and Y is a group consisting of Mg, Fe, Mn, Ni, Zn, Li, Al, and Cr. One or more selected from Z and one or more selected from the group consisting of Si and Al, where H ₂ O represents a water molecule bonded to an interlayer ion, and n represents an interlayer ion. As well as natural or synthetic).
Specific examples of the smectite group clay include, for example, montmorillonite, beidellite, nontronite, saponite, iron saponite, hectorite, soconite, stevensite, bentonite, and the like, or a substitution product, a derivative thereof, or a mixture thereof. .

The swellable mica is represented by the following general formula (II)
X _{0.5 to 1.0} Y _{2 to 3} (Z ₄ O ₁₀ ) (F, OH) ₂ ... General formula (II)
(However, X is at least one selected from the group consisting of Li, Na, K, Rb, Ca, Ba, and Sr, and Y is selected from the group consisting of Mg, Fe, Ni, Mn, Al, and Li) Z is one or more selected from the group consisting of Si, Ge, Al, Fe, and B), and is natural or synthesized.
These are water, a polar organic compound that is compatible with water at an arbitrary ratio, and a substance that swells in a mixed solvent of water and the polar organic compound. For example, lithium teniolite, sodium Type teniolite, lithium type tetrasilicon mica, sodium type tetrasilicon mica and the like, or a substituted product, a derivative thereof, or a mixture thereof.

Some of the swellable mica have a structure similar to vermiculites, and such vermiculites and the like can also be used. The vermiculite-equivalent products include three octahedron type and two octahedron type, and the following general formula (III)
_{(Mg, Fe, Al) 2~3} (Si 4-x Al x) O 10 (OH) 2 · (M +, M 2 + 1/2) x · nH 2 O
・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ General formula (III)
(Wherein M is an exchangeable cation of an alkali or alkaline earth metal such as Na and Mg, x = 0.6 to 0.9, n = 3.5 to 5). .

Swellable layered silicates may be used alone or in combination of two or more. Of these, smectite group clay and swellable mica are preferable from the viewpoint of dispersibility in the obtained multilayer extrusion foamed molded article, and sodium is interposed between layers such as montmorillonite, bentonite, hectorite, synthetic smectite, and swellable fluorine mica. Swelling mica having ions is more preferred.
Typical examples of bentonite include natural bentonite and purified bentonite. Also, organic bentonite can be used. The smectite in the present invention includes montmorillonite-modified products such as anionic polymer-modified montmorillonite, silane-treated montmorillonite, and highly polar organic solvent composite montmorillonite.

  The content of smectite such as bentonite is appropriately adjusted depending on the amount of water added and the like, but 0.1 to 10 parts by weight is preferably 0.2 to 8 parts by weight with respect to 100 parts by weight of the thermoplastic resin. Part by weight is more preferred, 0.3 to 7 parts by weight is particularly preferred, and 1 to 5 parts by weight is most preferred.

When the added amount of smectite is 0.1 to 10 parts by weight, water is well dispersed in the extruder, a foamed layer having a good cell structure free from bubble unevenness and voids is obtained, and good with no variation An extruded foam molded product having heat insulation performance can be obtained.
The mixing ratio of water / smectite is preferably 0.02 to 20, more preferably 0.1 to 10, particularly preferably 0.15 to 5, and most preferably 0.25 to 2, in terms of weight ratio.

As described above, the density of the foamed layer is not particularly limited as long as it is 500 kg / m ³ or less. However, in order to impart lightweight heat resistance, bending strength, and compressive strength, 20 to 65 kg / m ³ is preferable, 20 to 50 kg / m ³ is further preferable, and 20 to 40 kg / m ³ is more preferable. When the density is in the range of 20 to 60 kg / m ³ , a foamed molded article excellent in mechanical properties such as lightness, compressive strength, and heat insulation can be obtained.

The resin constituting the foam layer (hereinafter sometimes referred to as “foam layer constituent resin”) is arbitrarily selected from thermoplastic resins capable of extrusion foam molding.
Examples of the thermoplastic resin include polystyrene, styrene-acrylonitrile copolymer, styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid ester copolymer, and other styrene resins, polymethyl methacrylate, poly Vinyl resins such as acrylonitrile resin and polyvinyl chloride resin; Polyolefin resins such as polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-propylene-butene terpolymer, and cycloolefin (co) polymer Polyolefin resins whose rheology is controlled by introducing a branched structure or a crosslinked structure into these; Polyamide resins such as nylon 6, nylon 66, nylon 11, nylon 12, MXD nylon; polyethylene terephthalate, polybutylene terephthalate, Polyester resins such as rearylates; polycarbonate resins, polyphenylene ether resins, modified polyphenylene ether resins, polyoxymethylene resins, polyphenylene sulfide resins, polyphenylene sulfide resins, aromatic polyether resins, polyether ether ketone resins Engineering plastics such as liquid crystal resins; aliphatic polyester resins such as polylactic acid, and the like. These may be used alone or in admixture of two or more.

When a styrene resin is used as the resin constituting the foam layer, it is not particularly limited. For example, a styrene homopolymer obtained only from a styrene monomer, a monomer copolymerizable with styrene monomer and styrene, or Examples thereof include random, block or graft copolymers obtained from the derivatives, post-brominated polystyrene, modified polystyrene such as rubber-reinforced polystyrene, ABS resin, and the like. These can be used alone or in admixture of two or more.
Examples of monomers copolymerizable with styrene include styrene such as methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene. Derivatives; polyfunctional vinyl compounds such as divinylbenzene; (meth) acrylic such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, methacrylonitrile, α-chloroacrylonitrile, acrylonitrile Diene compounds such as budadiene or derivatives thereof; unsaturated carboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride; N-methylmaleimide, N-butylmaleimide, N-alkyl substituted maleimide compounds such as cyclohexylmaleimide, N-phenylmaleimide, N-4-diphenylmaleimide, N-2-chlorophenylmaleimide, N-4-bromophenylmaleimide, N-1-naphthylmaleimide; . These can be used alone or in admixture of two or more.

  Among these, as the resin constituting the foamed layer, polystyrene, styrene-acrylonitrile copolymer, styrene- (meta ) Acrylic acid copolymer, styrene- (meth) acrylic acid ester copolymer, maleic anhydride modified polystyrene, styrene-unsaturated dicarboxylic anhydride-N-alkyl substituted maleimide copolymer, high impact polystyrene, etc. Styrenic resins or vinyl resins such as polymethyl methacrylate and polyvinyl chloride resins; modified polyphenylene ether resins which are mixed resins of polystyrene resins and polyphenylene ether resins are preferred. Most preferred is a polystyrene homopolymer.

The foamed layer can be obtained by press-fitting water and a physical foaming agent into a foamed layer-constituting resin in a molten state and releasing it into a low-pressure region.
The physical blowing agent to be injected is not particularly limited, and examples thereof include saturated hydrocarbons having 3 to 5 carbon atoms such as propane, n-butane, i-butane, n-pentane, i-pentane, neopentane; dimethyl ether, diethyl Ethers such as ether, methyl ethyl ether, isopropyl ether, n-butyl ether, diisopropyl ether, furan, furfural, 2-methylfuran, tetrahydrofuran, tetrahydropyran; acetone, methyl ethyl ketone, diethyl ketone, methyl n-propyl ketone, methyl n- Ketones such as butyl ketone, methyl i-butyl ketone, methyl n-amyl ketone, methyl n-hexyl ketone, ethyl n-propyl ketone, ethyl n-butyl ketone; methanol, ethanol, propyl alcohol, i-propyl Alcohols such as alcohol, butyl alcohol, i-butyl alcohol, t-butyl alcohol; methyl formate, ethyl formate, propyl formate, butyl formate, amyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, propion Examples thereof include esters such as methyl acid and ethyl propionate; alkyl halides such as methyl chloride and ethyl chloride; inorganic foaming agents such as nitrogen, air and carbon dioxide. These foaming agents can be used alone or in admixture of two or more.

  Among the foaming agents, hydrocarbons such as propane, n-butane, i-butane, n-pentane, i-pentane, neopentane, and cyclopentane are preferable because they can achieve both extrusion foam moldability and high heat insulation. From the point that a low density extruded foam can be obtained, ethers such as dimethyl ether, diethyl ether and methyl ethyl ether; methanol, ethanol, propyl alcohol, i-propyl alcohol, butyl alcohol, i-butyl alcohol, t- Alcohols such as butyl alcohol; halogenated alkyls such as methyl chloride and ethyl chloride are preferred. Further, inorganic foaming agents such as nitrogen, air, carbon dioxide and the like are preferable from the viewpoint of nonflammability and excellent environmental compatibility.

The amount of the physical foaming agent that is press-fitted into the molten foam layer-constituting resin (thermoplastic resin) is appropriately selected according to the setting value of the foaming ratio, etc. It is preferable to set it as 1-20 weight part with respect to 100 weight part of plastic resins, and it is more preferable to set it as 3-8 weight part. When the total amount of the physical foaming agent is 1 to 20 parts by weight, there is no void in the foamed molded product, and a foamed layer having an appropriate foaming ratio that can control flame retardancy is obtained. As a result, characteristics such as light weight and heat insulation are exhibited.
The pressure at which the foaming agent is injected is not particularly limited as long as it is higher than the internal pressure of an extruder or the like.

As a method of adjusting the cell diameter distribution of the foamed layer, water can be used as the foaming agent, and it can be adjusted according to the type and amount of other foaming agent, the type and amount of water-absorbing substance, the molding conditions for extrusion foaming, and the like. As such molding conditions, for example, adjustment of the enlargement ratio of the thickness when the molten styrene-based resin composition is discharged into the atmosphere (that is, the die lip slit thickness and the molding die for making a rectangle) Height adjustment), molding resistance adjustment, and the like.
Examples of the method for controlling the average cell diameter in the thickness direction of the foam layer include inorganic compounds such as silica, talc, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, calcium carbonate, and sodium bicarbonate. And a method of adding the above-described nucleating agent and the above-described layered silicate to the styrene-based resin and adjusting the addition amount thereof. The average cell diameter is also adjusted by the type, composition and amount of the blowing agent. Furthermore, depending on the screw shape of the extruder as the melt kneading means, the heating temperature, the pressure, the amount of the melt-kneaded styrene resin composition discharged from the die lip, the die shape, the resin temperature at the time of discharge, etc. The bubble diameter is adjusted.

  In the production of the foam layer, inorganic compounds such as flame retardant, flame retardant aid, silica, talc, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, calcium carbonate, etc., as necessary , Processing aids such as sodium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, stearylamide compound, phenolic antioxidant, phosphorus stabilizer, nitrogen stabilizer, sulfur stabilizer It is preferable to add additives such as light-resistant stabilizers such as benzotriazoles and hindered amines, colorants such as antistatic agents and pigments.

  For more stable extrusion foaming, triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis {3 -(3,5-di-t-butyl-4-hydroxyphenyl) propionate}, 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino)- 1,3,5-triazine, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-t-butyl-4- Hydroxyphenyl) propionate, 3,5-di-t-butyl-4-hydroxy-benzyl phosphate-diethyl ester, 1,3,5-trimethyl-2,4,6- Hindered phenolic antioxidants such as lis (3,5-di-t-butyl-4-hydroxybenzyl) benzene and tris (3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; Phenylphosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-t-butylphenyl) pentaerythritol diphosphite, bisstearyl pentaerythritol diphosphite, bis (2 , 4-Di-t-butyl-4-methylphenyl) pentaerythritol diphosphite, tetrakis (2,4-di-t-butylphenyl) [1,1-biphenyl] -4,4′-diylbisphosphonite Phosphorus stabilizers such as 2,2,4-trimethyl-1,2-dihydroquinoline polymer, alkylated dipheny Amine stabilizers such as amine, octylated diphenylamine, 4,4′-bis (α, α-dimethylbenzyl) diphenylamine; 3,3-thiobispropionic acid didecyl ester, 3,3′-thiobispropionic acid diester It is preferable to add a sulfur-based stabilizer such as octadecyl ester.

  The thickness of the foamed layer is appropriately selected according to the thickness of the multilayer extruded foamed molded product and the number of foamed layers in the multilayer extruded foamed molded product (number of units composed of foamed layer / non-foamed layer / foamed layer).

The non-foamed layer constituting the multilayer extruded foamed molded product obtained by the method for producing a multilayer extruded foamed molded product of the present invention is larger than the thicker portion of the cell walls or cell wall joints of the cells constituting the foamed layer. A layer having a thickness of 1.1 times or more. The density of the non-foamed layer is preferably more than 500 kg / m ³ , although it depends on the density of the resin and additives used. The non-foamed layer may contain fewer bubbles than the foamed layer.
The resin or resin composition constituting the non-foamed layer (hereinafter sometimes referred to as “non-foamed layer constituting resin”) is the foam layer obtained in order to obtain the desired highly heat-insulating multilayer extruded foam Therefore, it is preferable to select a resin that is compatible with the resin constituting the foamed layer.

  The thermoplastic resin having compatibility with the resin constituting the foam layer is not particularly limited, and examples thereof include styrene resins such as polystyrene; polyolefin resins such as polypropylene, polyethylene, and ethylene propylene random copolymer; nylon 6, Polyamide resins such as nylon 66 and nylon 12; polyester resins such as polyethylene terephthalate and polybutylene terephthalate; polycarbonate resins; polyphenylene ether resins, modified polyphenylene ether resins; polyoxymethylene resins, polyarylate resins, polyphenylene sulfide Resin, polyacrylonitrile, polyvinyl alcohol, ethylene-vinyl acetic acid copolymer, polyacrylic acid, polymethyl methacrylate, thermoplastic phenol resin, etc. It can be used as a mixture of at least alone or in combination. Among these, polystyrene resins, polyolefin resins, polyphenylene ether resins, and modified polyphenylene ether resins are preferred because they are excellent in compatibility with the resin constituting the foam layer and are easy to mold. A resin is more preferable.

The styrenic resin is not particularly limited, and for example, a styrene homopolymer obtained only from a styrene monomer, a random, block or graft obtained from a monomer copolymerizable with a styrene monomer and styrene or a derivative thereof. Examples thereof include copolymers, modified polystyrene such as post-brominated polystyrene and rubber-reinforced polystyrene, and ABS resins. These can be used alone or in admixture of two or more.
Examples of monomers copolymerizable with styrene include methylstyrene, dimethylstyrene, ethylstyrene, diethylstyrene, isopropylstyrene, bromostyrene, dibromostyrene, tribromostyrene, chlorostyrene, dichlorostyrene, and trichlorostyrene. Polyfunctional vinyl compounds such as divinylbenzene, (meth) acrylic compounds such as acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, methacrylonitrile, α-chloroacrylonitrile, acrylonitrile Diene compounds such as budadiene or derivatives thereof, unsaturated carboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride, N-methylmaleimide, N-butylmaleimide, N-cycl Hexyl maleimide, N- phenylmaleimide, N-4-diphenyl-maleimide, N-2-chlorophenyl maleimide, N-4-bromophenyl maleimide, N- alkyl-substituted maleimide compounds such as N-1- naphthyl maleimide; and the like. These can be used alone or in admixture of two or more.

In particular, when a styrene resin is used as the constituent resin of the non-foamed layer, styrene homopolymer, styrene acrylonitrile copolymer, (meth) acrylic acid copolymer polystyrene, maleic anhydride are used from the viewpoint of compatibility with the foamed layer. It is more preferable to use modified polystyrene, styrene-unsaturated dicarboxylic anhydride-N-alkyl substituted maleimide copolymer, and high impact polystyrene, and most preferably styrene homopolymer.
Examples of adhesive and adhesive resins include polyolefin resins, vinyl chloride resins, vinylidene chloride resins, vinyl alcohol resins, ethylene-vinyl alcohol copolymer resins, acrylic resins, and styrene-butadiene copolymers. Resins, natural rubber resins, chloroprene resins, and resins obtained by blending the above resins with tackifier resins such as rosins, rosin derivatives, petroleum resins, terpene resins, phenol resins, rosin phenol resins, and ketone resins Examples thereof include compositions.

The structure of the non-foamed layer is not particularly limited, and any structure of a single layer or multiple layers can be adopted.
The thickness of the non-foamed layer is appropriately selected according to the thickness of the extruded foamed molded product and the number of foamed layers in the multilayer extruded foamed molded product (number of units composed of foamed layer / non-foamed layer / foamed layer). 10-500 micrometers is preferable, 20-300 micrometers is more preferable, 30-200 micrometers is especially preferable, and 40-100 micrometers is the most preferable. When the thickness of the non-foamed layer is in the range of 10 to 500 μm, an extruded foam molded product having lightness and heat insulation can be obtained.

When manufacturing non-foamed layers, plasticizer, flame retardant, flame retardant aid, silica, talc, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, calcium carbonate, as necessary Inorganic compounds such as sodium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, stearyl amide compound and other processing aids, phenolic antioxidants, phosphorus stabilizers, nitrogen stabilizers, It is preferable to add additives such as sulfur stabilizers, light-resistant stabilizers such as benzotriazoles and hindered amines, antistatic agents, and colorants such as pigments.
Among these additives, the plasticizer is used so as not to disturb the flow at the resin joining interface during the production of the multilayer extrusion foamed molded article obtained by the method for producing a multilayer extrusion foamed molded article of the present invention. Since it works effectively when adjusting the melt viscosity of the non-foamed layer-constituting resin to be close to the melt viscosity of the foaming agent-containing resin, it is preferably added.

The plasticizer added to the non-foamed layer constituting resin is not particularly limited, and any compound generally used as a plasticizer can be used. For example, dimethyl phthalate (DMP), diethyl phthalate (DEP) ), Dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DOP), dinormaloctyl phthalate (DNOP), diisononyl phthalate (DINP), dinonyl phthalate (DNP), diisodecyl phthalate (DIDP), Phthalates such as butylbenzyl phthalate (BBP) and phthalic acid mixed ester (C6-C11); dioctyl adipate (DOA), diisononyl adipate (DINA), dialkyl adipate (C6, 8, 10) ( 610A), dialkyl adipate (C7, C9) (79A) azelaic acid di Cutyl (DOZ) dibutyl sebacate (DBS), dioctyl sebacate (DOS), tricresyl phosphate (TCP), tributyl acetylcitrate (ATBC), epoxidized soybean oil (ESBO), trioctyl trimellitic acid (TOTM), chlorine Non-phthalic acid esters such as modified paraffins.
The amount of plasticizer added to the non-foamed layer constituting resin is appropriately selected depending on the target melt viscosity, but is preferably 1 to 20 parts by weight, and 2 to 15 parts by weight with respect to 100 parts by weight of the non-foamed layer constituting resin. More preferably, 3 to 12 parts by weight is particularly preferable, and 4 to 10 parts by weight is preferable. When the addition amount of the plasticizer is in the range of 1 to 20 parts by weight with respect to 100 parts by weight of the non-foamed layer constituting resin, a non-foamed layer with no discharge fluctuation during extrusion and no surface bleed-out after extrusion is obtained. .

  In the present invention, the method of laminating each molten resin in a laminating apparatus with a laminating apparatus is not particularly limited, and for example, a feed block method, a multi-manifold method, a special table generally used for co-extruded films Examples include a method in which a plurality of divided flows described in JP-A-2005-523831, JP-A-2004-249520, and the like are formed and then sequentially stacked.

The temperature of the laminating apparatus in producing the extruded foam is preferably ± 10 ° C. or lower even if it is equal to or different from the resin temperature of the foaming agent-containing molten resin supplied to the laminating apparatus. When the temperature difference is ± 10 ° C. or less, molding with a die can be performed at an appropriate foaming temperature, and an extruded foam having a foam layer with a high magnification and a low closed cell ratio can be obtained.
The pressure in the laminating apparatus when producing the extruded foam is set to a pressure at which the foaming agent-containing molten resin supplied to the laminating apparatus does not cause foaming in the laminating apparatus. However, the pressure that does not cause foaming in the laminating apparatus cannot be generally set because it depends on the type of foaming agent, the amount of foaming agent, and the temperature of the foaming agent-containing molten resin.

  In the present invention, the foam molding method is not particularly limited, for example, using a molding die, a molding roll, etc., in which a foam obtained by releasing pressure from a slit die is placed in close contact with or in contact with the slit die. A general method for molding a plate-like foam having a large size can be used.

Regarding the melt kneading of the constituent resin of the foam layer,
(I) The thermoplastic resin is mixed with the additive as necessary, and then melted by heating.
(Ii) One or more selected from the above-mentioned additives are mixed with the thermoplastic resin, if necessary, and then melted by heating, and the remaining additive is added to the thermoplastic resin as it is, or liquefied or melted as necessary. Then heat and mix,
(Iii) One or more additives selected from the above-mentioned additives are mixed with a thermoplastic resin in advance, and then a heated and melted composition is prepared. Then, the composition and the remaining additive are prepared. , If necessary, mix the thermoplastic resin again, supply to the extruder and melt by heating,
Etc., thermoplastic resin, if necessary, supply the additive to a hot melt extruder,
Thereafter, a foaming agent is added to the thermoplastic resin under high pressure conditions at an arbitrary stage to form a fluid gel. Thereafter, the fluid gel is cooled to a temperature suitable for extrusion foaming and then supplied to the laminating apparatus.

  There are no particular limitations on the heating temperature, melt kneading time, and melt kneading means when heating and kneading the thermoplastic resin and additives such as a foaming agent. Although the heating temperature should just be more than the temperature which the thermoplastic resin to use melt | dissolves, the temperature which suppresses the molecular degradation of resin by the influence of a flame retardant etc. as much as possible, for example, about 150-280 degreeC is preferable. The melt-kneading time varies depending on the amount of extrusion per unit time, the melt-kneading means and the like and cannot be determined unconditionally. However, the time required for uniformly dispersing and mixing the thermoplastic resin and the foaming agent is appropriately selected. Further, examples of the melt-kneading means include a screw type extruder, but there is no particular limitation as long as it is used for ordinary extrusion foaming. However, in order to suppress the molecular deterioration of the resin as much as possible, it is preferable to use a low shear type screw shape for the screw shape.

Further, regarding the melt kneading of the constituent resin of the non-foamed layer, for example,
(I) The thermoplastic resin is mixed with the additive as necessary, and then melted by heating.
(Ii) One or more selected from the above-mentioned additives are mixed with the thermoplastic resin, if necessary, and then melted by heating, and the remaining additive is added to the thermoplastic resin as it is, or liquefied or melted as necessary. Then heat and mix,
(Iii) One or more additives selected from the above-mentioned additives are mixed with a thermoplastic resin in advance, and then a heated and melted composition is prepared. Then, the composition and the remaining additive are prepared. , If necessary, mix the thermoplastic resin again, supply to the extruder and melt by heating,
The thermoplastic resin and, if necessary, the additive are supplied to an extruder and heated and melt-kneaded. Thereafter, the melt-kneaded product is supplied to a laminating apparatus.

  There are no particular limitations on the heating temperature, melt kneading time, and melt kneading means when the thermoplastic resin and additive are heat melt kneaded. The heating temperature may be equal to or higher than the temperature at which the thermoplastic resin used melts, but the temperature difference may be within ± 10 ° C. even if the temperature is equal to or different from the set temperature of the laminating apparatus to which the molten resin is supplied. preferable. When the temperature difference is ± 10 ° C. or less, it is possible to obtain a good extruded foam that does not have bubble breakage at the interface portion between the foamed layer and the non-foamed layer and does not have poor adhesion. The melt-kneading time varies depending on the amount of extrusion per unit time, the melt-kneading means, etc., and thus cannot be generally determined, but the time required for uniformly dispersing and mixing the thermoplastic resin and the additive is appropriately selected. . Examples of the melt-kneading means include a screw type extruder, but there is no particular limitation as long as it is used for ordinary resin extrusion. However, in order to suppress the molecular deterioration of the resin as much as possible, it is preferable to use a low shear type screw shape for the screw shape.

  The thickness of the multilayer extrusion foam molded article obtained by the method for producing a multilayer extrusion foam molded article of the present invention is not particularly limited, and is appropriately selected depending on the application. For example, in the case of a heat insulating material used for a building material or the like, in order to give a preferable heat insulating property, bending strength and compressive strength, the thickness of a normal plate-like material is less than a thin material such as a sheet. Some are preferred, usually 10 to 150 mm, preferably 20 to 100 mm.

The equivalent thermal conductivity at 20 ° C. of the multilayer extrusion foam molded article obtained by the method for producing a multilayer extrusion foam molded article of the present invention is 0.034 W / (m · K) (0.0292 kcal / (m · h · ° C.). )) Or less, preferably 0.032 W / (m · K) (0.0275 kcal / (m · h · ° C.)) or less, more preferably 0.030 W / (m · K) (0.0258 kcal / (m · h · ° C.) The following are particularly preferred:
The foamed molded product having an equivalent thermal conductivity of 0.034 W / (m · K) or less is suitably used as a building material application, and contributes to providing a comfortable living space.

  The multilayer extrusion foam molded article obtained by the method for producing a multilayer extrusion foam molded article of the present invention has various uses such as floor materials, wall materials, roof materials and the like from the viewpoint of its excellent light weight and heat insulation properties. It can be suitably used for automobile members such as structural members, heat insulating materials for cold cars, vehicle bumpers, and automobile ceiling materials, and civil engineering members such as antifreezing agents for the ground.

Next, the present invention will be described in detail based on examples, but the present invention is not limited to such examples. Unless otherwise specified, “%” represents wt%.
Evaluation methods for Examples and Comparative Examples are as follows.
(1) Dimensions of extruded foam molding [unit: mm]
For three multilayer extruded foam samples sampled at time intervals, the thickness was measured at the center (the middle point in the width direction) in the width direction (horizontal direction orthogonal to the extrusion direction, left and right direction), and the average value was measured. Was calculated.
About three multilayer extrusion-foaming moldings sampled at time intervals, the width at the center in the thickness direction (the middle point in the thickness direction) was measured, and the average value was calculated. In addition, the part located in the value of 1/2 of the said thickness from the upper surface of a multilayer extrusion foaming molding and the value of 1/2 of the said width from the left side surface was made into the center part.
(2) Density of extruded foam molding [unit: kg / m ³ ]
For three extruded foam moldings sampled at time intervals, the foam density was measured according to the method described in JIS K7222-1999 "Foamed plastics and rubbers-Measurement of apparent density", and the average value was measured. Was calculated.
(3) Thermal conductivity of extruded foam molding [unit: W / (m · K)]
The thermal conductivity of the extruded foamed product was measured using a thermal conductivity measuring device (Eihiro Seiki, HC-074-300). The thermal conductivity when the partial pressure of air in the foam of the extruded foam body is 51 kPa is shown in the examples.
(4) Partial pressure of air in the foam of the extruded foam molded body After the extruded foam molded body was cut out and 10 mm from the cut surface was removed, the width direction was 25 mm from the center in the width direction, the length direction was 25 mm, and the thickness direction was the molded body. It cuts out with the thickness as it is, analyzed and measured the amount of air in an extrusion foaming molding using a gas chromatograph (Shimadzu GC-14A), and calculating an average value. The partial pressure of air was determined.
(5) Flow velocity distribution The flow velocity distribution was measured under the following assumptions using finite element flow analysis software POLYFLOW.
・ No distinction is made between molten resin containing foaming agent and molten resin not containing foaming agent, and foaming in the die is ignored.
・ The laminar flow is a highly viscous flow (Newtonian flow with a viscosity of 1.7 × 10 ⁶ Pa · s), and the inertia term is ignored.
・ The temperature inside the equipment is constant and the flow is isothermal.

Example 1
[Method for Producing Molten Resin A Containing Foaming Agent]
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z) 0 with respect to 100 parts by weight of polystyrene (PS Japan, trade name: PSJ-polystyrene 680, MFR = 7.0 g / 10 min) 0.5 part by weight, calcium stearate (manufactured by Sakai Chemical Industry Co., Ltd., trade name: SC-P), 0.3 part by weight, liquid paraffin (manufactured by Nippon Oil Corporation, trade name: Polybutene LV-50) 0.1 weight The mixture consisting of parts was dry blended to obtain a styrene resin composition. The styrene-based resin composition was supplied at 60.5 kg / hour to a two-stage extruder in which a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm were connected in series.
The styrenic resin composition supplied to the first extruder is kneaded by heating to 180 ° C., and as a foaming agent near the tip of the first extruder (the side connected to the second extruder) Styrenic resin composition obtained by melting 4.0% by weight of i-butane (manufactured by Mitsui Chemicals) and 4.0% by weight of dimethyl ether (manufactured by Taiyo Liquefaction Gas Co., Ltd.) with respect to 100% by weight of the resin composition. Press fit into. At this time, the resin pressure at the tip of the first extruder was 15.2 MPa, while the press-fitting pressure of the foaming agent was 13.3 MPa.
In the second extruder connected to the first extruder, after the resin temperature was cooled to 121 ° C., it was divided into two, and a molten resin A containing a foaming agent was provided at the tip of the second extruder 2 It supplied to the seed 3 layer multilayer lamination feed block (made by Pla Giken Co., Ltd.).

[Method for producing molten resin B containing no blowing agent]
For 100 parts by weight of polystyrene (manufactured by PS Japan Co., Ltd., trade name: PSJ-polystyrene 679, MFR = 18 g / 10 min), dimethyl phthalate (made by Daihachi Chemical Industry Co., Ltd., trade name: DMP) 8 as a plasticizer 0.0 part by weight was added to prepare a master batch in advance. The obtained resin was supplied to an extruder having a diameter of 50 mm at 2.3 kg / hour. The supplied resin was heated to 125 ° C., melted and kneaded, and the molten resin B containing no foaming agent was supplied to the feed block for the two-kind / three-layer multilayer lamination without diverting.

[First step: A step of obtaining a laminated molten resin C by joining a molten resin A containing a blowing agent and a molten resin B not containing a blowing agent in the thickness direction]
Foam in which molten resin B not containing a foaming agent is divided into two in the thickness direction under a pressure of 3.1 MPa, within the feed block for the two-type three-layer multi-layer lamination temperature-controlled at 120 ° C. A laminated molten resin C was obtained by merging at a thickness of 11 mm / 3 mm / 11 mm, respectively, so as to be sandwiched between molten resins A containing an agent.

[Second Step 2 to Fifth Step: A Step of Obtaining a Doubled Laminated Molten Resin E by a Double Layering Step]
The laminated molten resin C was supplied to a laminated doubling apparatus (manufactured by Pla Giken Co., Ltd.) that was temperature-controlled at 120 ° C. in the laminated doubling process shown in FIG. Note that the length L (see FIG. 8B) of the rectification process was 30 mm.
In addition, the average flow velocity in the thickness direction of the doubling laminated molten resin E in each part in the width direction immediately after joining the divided laminated molten resins D1 and D2 in the fifth step ((maximum value of flow velocity in the thickness direction + minimum flow velocity in the thickness direction Value) / 2) ratio of flow rate difference in the thickness direction (maximum value of flow rate in the thickness direction-minimum value of flow rate in the thickness direction) (flow rate difference in the thickness direction / average flow velocity in the thickness direction). As a result of calculation by software (see FIG. 8A), the maximum value was 0.28.

[Sixth Step: Step of Obtaining Multilayer Extrusion Foam Molded Body]
Double layered molten resin E has a rectangular cross section with a thickness of 1.6 mm and a width of 50 mm, and a combined multi-layer flow is pushed out into the atmosphere from a die lip controlled at 80 ° C. 2 and having a cross section as shown in FIG. 2, for example, a rectangular parallelepiped shape having a thickness of 29 mm and a width of 230 mm and having a five-layer structure of foamed layer / non-foamed layer / foamed layer / non-foamed layer / foamed layer An extruded foam molding was obtained.
The obtained multilayer extrusion foamed molded article has a structure in which the foamed layer and the non-foamed layer constituting the molded article are laminated slightly obliquely in the thickness direction, the density of the molded article is 33 kg / m ³ , and the air partial pressure The thermal conductivity at 51 kPa was 0.0283 W / (m · K).

(Example 2)
In the double layering step, the same as in Example 1 except that the length L of the rectifying step (see FIG. 8B) is 50 mm, a rectangular parallelepiped shape having a thickness of 25 mm and a width of 235 mm, and non-foamed layer An extruded foam molded article having a five-layer structure of layer / foamed layer / non-foamed layer / foamed layer was obtained.
The obtained multilayer extrusion foamed molded article has a structure in which the foamed layer and the non-foamed layer constituting the molded article are horizontally laminated in the thickness direction, the molded article density is 35 kg / m ³ , and the air partial pressure is 51 kPa. The thermal conductivity of was 0.0279 W / (m · K).
In addition, the average flow velocity in the thickness direction of the doubling laminated molten resin E in each part in the width direction immediately after joining the divided laminated molten resins D1 and D2 in the fifth step ((maximum value of flow velocity in the thickness direction + minimum flow velocity in the thickness direction). Value) / 2) ratio of flow rate difference in the thickness direction (maximum value of flow rate in the thickness direction-minimum value of flow rate in the thickness direction) (flow rate difference in the thickness direction / average flow velocity in the thickness direction). As a result calculated by software (see FIG. 8A), the maximum value was 0.15.

(Example 3)
In the double layering step, the same as in Example 1 except that the length L of the rectifying step (see FIG. 8B) is 80 mm, a rectangular parallelepiped shape with a thickness of 26 mm and a width of 232 mm / non-foamed An extruded foam molded article having a five-layer structure of layer / foamed layer / non-foamed layer / foamed layer was obtained.
The obtained multilayer extrusion foamed molded article has a structure in which a foamed layer and a non-foamed layer constituting the molded article are laminated horizontally in the thickness direction, the density of the molded article is 37 kg / m ³ , and the air partial pressure is 51 kPa. The thermal conductivity of was 0.0277 W / (m · K).
In addition, the average flow velocity in the thickness direction of the doubling laminated molten resin E in each part in the width direction immediately after joining the divided laminated molten resins D1 and D2 in the fifth step ((maximum value of flow velocity in the thickness direction + minimum flow velocity in the thickness direction). Value) / 2) ratio of flow rate difference in the thickness direction (maximum value of flow rate in the thickness direction-minimum value of flow rate in the thickness direction) (flow rate difference in the thickness direction / average flow velocity in the thickness direction). As a result of calculation by software (see FIG. 8A), the maximum value was 0.09.

(Comparative Example 1)
In the layer doubling process, the same as in Example 1 except that the length of the rectifying part (see FIG. 8B) was set to 0 mm, and foamed layer / non-foamed layer / foamed layer / non-foamed layer / foamed An extruded foam molded body having a five-layer structure was obtained.
The obtained multilayer extrusion foamed molded article has a structure in which a foamed layer and a non-foamed layer constituting the molded article are laminated obliquely in the thickness direction, and the density of the molded article is 35.5 kg / m ^3. The thermal conductivity at a pressure of 51 kPa was 0.0295 W / (m · K).
In addition, the average flow velocity in the thickness direction of the doubling laminated molten resin E in each part in the width direction immediately after joining the divided laminated molten resins D1 and D2 in the fifth step ((maximum value of flow velocity in the thickness direction + minimum flow velocity in the thickness direction). Value) / 2) ratio of flow rate difference in the thickness direction (maximum value of flow rate in the thickness direction-minimum value of flow rate in the thickness direction) (flow rate difference in the thickness direction / average flow velocity in the thickness direction). As a result of calculation by software (see FIG. 8A), the maximum value was 0.90.

Example 4
The doubling lamination molten resin E was obtained by changing the lamination doubling process to the process shown in FIG. 6 (see also FIG. 9B), and otherwise performing the same process as in Example 1.
The obtained multilayer extrusion foamed molded article has a structure in which a foamed layer and a non-foamed layer constituting the molded article are laminated horizontally in the thickness direction, the density of the molded article is 36 kg / m ³ , and the air partial pressure is 51 kPa. The thermal conductivity of was 0.0275 W / (m · K).
In addition, the average flow velocity in the thickness direction of the doubling laminated molten resin E in each part in the width direction immediately after joining the divided laminated molten resins D1 and D2 in the fifth step ((maximum value of flow velocity in the thickness direction + minimum flow velocity in the thickness direction). Value) / 2) ratio of flow rate difference in the thickness direction (maximum value of flow rate in the thickness direction-minimum value of flow rate in the thickness direction) (flow rate difference in the thickness direction / average flow velocity in the thickness direction). As a result of calculation by software (see FIG. 9A), no difference in flow velocity (difference in flow rate between the left and right sides) was observed in all parts in the width direction.

(Example 5)
The doubling lamination molten resin E was obtained in the same manner as in Example 1 except that the lamination doubling process was the process shown in FIG. 7 (see also FIG. 10B).
The obtained multilayer extrusion foamed molded article has a structure in which a foamed layer and a non-foamed layer constituting the molded article are laminated horizontally in the thickness direction, the density of the molded article is 37 kg / m ³ , and the air partial pressure is 51 kPa. The thermal conductivity of was 0.0277 W / (m · K).
In addition, the average flow velocity in the thickness direction of the doubling laminated molten resin E in each part in the width direction immediately after joining the divided laminated molten resins D1 and D2 in the fifth step ((maximum value of flow velocity in the thickness direction + minimum flow velocity in the thickness direction). Value) / 2) ratio of flow rate difference in the thickness direction (maximum value of flow rate in the thickness direction-minimum value of flow rate in the thickness direction) (flow rate difference in the thickness direction / average flow velocity in the thickness direction). As a result of calculation by software (see FIG. 10A), no difference in flow velocity (difference in flow rate between the left and right sides) was observed in each part in the width direction.

  By the above Examples 1 to 5 and Comparative Example 1, the two divided laminated molten resins D1 and D2 were aligned so as to be aligned vertically between the fourth step and the fifth step in the double layering step. A rectifying process that reduces the difference between the left and right flow velocity by moving the predetermined length (the length L of the rectifying process) to the downstream side while maintaining the positional relationship in the left-right direction while the two divided laminated molten resins D1, D2 are separated. In the doubled laminated molten resin E after merging in the fifth step, the difference in flow velocity in the thickness direction at each part in the width direction is reduced, and the foam constituting the molded body in the obtained multilayer extrusion foamed molded body It was confirmed that the phenomenon in which the layer and the non-foamed layer were laminated obliquely could be eliminated and the heat insulation performance could be improved.

A Molten resin containing a foaming agent B Molten resin not containing a foaming agent C Laminated molten resin D1, D2 Split laminated molten resin E Double layered molten resin F Flow direction L Length of rectifying path 1 Foaming extruder 2 For non-foaming Extruder 3 Laminating apparatus 4 Double doubling apparatus 5 Mold 6 Molding machine 7 Multi-layer extruded foam 8 Foamed layer 9 Non-foamed layer 10 Rectifier

Claims (5)

In a method for producing an extrusion foamed molded article in which a heat-plasticized molten resin is extruded in the flow direction while being continuously shaped by shaping it into a shape of a constant cross section with a mold, at least one molten resin containing a foaming agent and the foaming agent are used. A first step of obtaining a laminated molten resin by joining at least one molten resin not contained in a vertical direction that is a thickness direction under high pressure, and dividing the laminated molten resin at a horizontal center that is a width direction, A second step of separating the left and right two divided laminated molten resins by separating them, and a third step of separating the left and right two divided laminated molten resins in the vertical direction so that one lower end is above the other upper end; These two divided laminated molten resins are made to approach in the left-right direction, and the center in the left-right direction of these two divided laminated molten resins passes through the center in the left-right direction of the laminated molten resin and is perpendicular to the flow direction. A fourth step of aligning the two divided laminated molten resins so as to be aligned vertically in a state where they are separated to a position where they are vertically overlapped so as to be positioned in the plane; A method for producing a multilayer extrusion foamed molded article comprising a fifth step of merging and obtaining a doubled laminated molten resin,
Between the fourth step and the fifth step, the two divided laminated molten resins are separated while maintaining the positional relationship in the left-right direction so that the two divided laminated molten resins are aligned vertically. A method for producing a multilayer extrusion foamed molded article, characterized in that a straightening step for reducing the difference in flow rate between the left and right sides is provided by moving a predetermined length downstream.   2. The multilayer extrusion foamed molded article according to claim 1, wherein a width expanding step is provided between the first step and the second step to expand the width twice without changing the cross-sectional area of the laminated molten resin. Manufacturing method.   Between each of the second step and the third step, between the third step and the fourth step, or between the fourth step and the fifth step, a sectional area of each of the divided laminated molten resins. The manufacturing method of the multilayer extrusion foaming molding of Claim 1 which provides the width expansion process which expands a width twice without changing this.   The manufacturing method of the multilayer extrusion foaming molding of Claim 1 which provides the width expansion process which expands a width twice without changing the cross-sectional area of the said doubling lamination molten resin after the said 5th process. Foam supplied by pressurizing molten resin containing a foaming agent in an extrusion foamed molded product manufacturing apparatus that continuously molds the molten resin that has been heat plasticized in the flow direction while shaping it into a fixed cross-section with a mold. Extruder for extrusion and non-foaming extruder for supplying molten resin containing no blowing agent under pressure, at least one molten resin containing a blowing agent and at least one containing no blowing agent supplied from these extruders A laminating apparatus that joins two molten resins in the vertical direction, which is the thickness direction, to form a laminated molten resin, and divides the laminated molten resin at the center in the left-right direction, which is the width direction, to form two divided laminated molten resins. A lamination doubling device that merges molten resins so as to overlap each other to form a doubled laminated molten resin, and releases the doubled laminated molten resin under atmospheric pressure to vaporize the foaming agent. An apparatus for producing a multi-layer extrusion foaming body having a molding die for high doubled by a,
The lamination doubling device separates the two left and right divided laminated molten resins in the vertical direction so that one lower end is above the other upper end, and these two divided laminated molten resins are moved in the left and right directions. The two split laminates are stacked up to a position where the center of the two split laminate molten resins in the vertical direction passes through the center of the laminate molten resin in the left and right direction and is in a vertical plane parallel to the flow direction. After aligning the melted resin so that they are aligned vertically, the two split laminate melts are maintained while maintaining the positional relationship in the left-right direction so that the two split laminate molten resins are aligned vertically A rectifying path that moves the resin to the downstream side by a predetermined length while the resin is separated is provided, and after the flow velocity difference between the left and right is reduced by this rectifying path, the divided laminated molten resins are joined so as to overlap each other. Apparatus for manufacturing a multilayer extrusion foamed molded article according to claim Rukoto.

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