JP2012219174A - Extrusion foamed molding having excellent thermal insulation performance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extrusion foamed molding for a thermal insulation material by which remarkable improvement effect of the thermal insulation performance is attained without using fluorocarbon as a foaming agent.SOLUTION: The multilayer extrusion foamed molding is obtained by extruding a laminated molten resin obtained by joining at least one molten resin containing a foaming agent and at least one molten resin containing no foaming agent which are pressurized by a gear pump in the vertical direction of the thickness direction under high pressure, extruding the laminated molten resin in the flow direction, opening under atmospheric pressure and continuously molding while arranging the shape having a fixed cross-section by a mold. The multilayer extrusion foamed molding has a structure formed by laminating a foamed layer and a non-foamed layer in the thickness direction and is constituted of the bubbles having 0.07-0.25 mm average foam diameter.

Description

  The present invention relates to an extruded foam molded article suitably used as a heat insulating material for buildings, automobiles, civil engineering and the like.

  Conventionally, the multilayer extrusion foaming composed of a foamed layer / non-foamed layer has been studied mainly in the form of a film and a sheet using a polypropylene resin (for example, Patent Documents 1 to 4).

  In addition, there is a study example of multilayer extrusion foaming composed of a foamed layer / non-foamed layer focusing on a polystyrene-based extruded foam board (Patent Documents 5 and 6).

  Patent Document 5 is a technique for obtaining a foamed molded article by integrating a molten resin containing a water-containing foaming agent and a molten resin including a brominated aliphatic flame retardant, and then extruding the composite flow from a die to a low-pressure zone. When it comes into contact with water in a high temperature region, it is possible to use a brominated aliphatic flame retardant that generates an acidic decomposition product and causes corrosion of equipment by acidification of the resin, and a water-containing foaming agent.

  This technology focuses on fire resistance, and there is no suggestion about heat insulation and heat insulation performance, which are general uses of polystyrene-based extruded foam boards. In fact, the improvement in fire resistance in the description of the examples is that of bromine. In addition to the increase in the total content, a tendency to be caused by an increase in the density of the composite structure, which is disadvantageous to the heat insulation performance, is recognized, and thus it is estimated that the technique is not focused on the heat insulation performance improvement.

  Patent Document 6 is a coextruded foamed composite, which is a technique for adding an additive such as carbon black to a non-foamed layer to reduce thermal conductivity. However, the blowing agents used are chlorofluorocarbons, which are required to be completely abolished from the viewpoint of protecting the global environment, and in order to achieve heat insulation performance without using chlorofluorocarbons as the blowing agent. Need to be improved.

  As a technique for improving the heat insulation property of polystyrene-based extruded foam board without using chlorofluorocarbon as a foaming agent, it is known to have a cell structure composed of small cells and large cells (for example, Patent Documents 7 to 9). ).

However, in recent years, with increasing demand for comfort and energy saving in living spaces, there has been a demand for further improvement of heat insulation performance of conventional heat insulating materials obtained using the techniques of Patent Documents 7 to 9, and chlorofluorocarbon as a blowing agent. At present, there is a demand for the development of an extruded foam board having high heat insulation performance without using any kind.
Japanese Patent Laid-Open No. 10-748 JP-T-4-505594 Japanese Examined Patent Publication No. 7-98349 WO2008 / 008875 publication Japanese Patent No. 3474568 Japanese National Patent Publication No. 6-510247 JP 2007-321068 A JP 2005-514506 A JP 2004-277673 A

  This invention solves the said subject, and it aims at providing the extrusion foaming molding for heat insulating materials which has a remarkable improvement effect of heat insulation performance, without using chlorofluorocarbons as a foaming agent.

As a result of intensive studies to solve the above-mentioned problems, the present inventor found the following matters and completed the present invention.
(1) When a molten resin containing a blowing agent and a molten resin not containing a blowing agent are merged in the thickness direction (vertical direction) under high pressure to produce a laminated molten resin, the molten resin containing the blowing agent is removed by a gear pump. By adjusting the resin pressure of the molten resin containing the foaming agent by increasing the pressure, the cell diameter of the foamed layer constituting the multilayer extrusion foamed molded article obtained by releasing the laminated molten resin under atmospheric pressure can be adjusted. Possible.
(2) The heat insulation performance is improved by suppressing the average cell diameter in the thickness direction of the foamed layer to 0.25 mm or less.

That is, the present invention
[1] Laminated molten resin obtained by merging at least one molten resin containing a blowing agent pressurized by a gear pump and at least one molten resin not containing a blowing agent in a vertical direction that is a thickness direction under high pressure Is extruded under atmospheric pressure while being extruded in the flow direction, and is formed into a shape having a constant cross section with a mold and continuously molded, and the multilayer extruded foam molded product is obtained by Multi-layer extrusion foaming characterized by having a structure in which a foamed layer is laminated in the thickness direction through a non-foamed layer, and the foamed layer is composed of bubbles having an average cell diameter of 0.25 mm or less in the thickness direction Molded body,
[2] At least one molten resin containing a blowing agent pressurized by a gear pump and at least one molten resin not containing a blowing agent pressurized by a gear pump are merged in a vertical direction that is a thickness direction under high pressure. A multilayer extruded foam obtained by opening the laminated molten resin obtained in the flow direction under atmospheric pressure while extruding it in a flow direction, adjusting the shape to a constant cross-section with a mold, and continuously molding the multilayer molten resin. The extruded foam molded body has a structure in which a foamed layer is laminated via a non-foamed layer in the thickness direction, and the foamed layer is composed of bubbles having an average cell diameter of 0.25 mm or less in the thickness direction. A multilayer extrusion foamed molded product,
[3] The multilayer extruded foam molded article according to [1] or [2], wherein the density of the multilayer extruded foam molded article is 20 to 65 Kg / m ³ .
[4] The multilayer extruded foam molded article according to [1] or [2], wherein the density of the multilayer extruded foam molded article is 20 to 40 kg / m ³ .
[5] The multilayer extruded foam molded article according to any one of [1] to [4], wherein an average cell diameter in the thickness direction of the foamed layer is 0.07 to 0.25 mm,
[6] The extrusion-molded article according to any one of [1] to [5], wherein the extruded foam-molded product has a plurality of the structures in which a foam layer is laminated via a non-foam layer in the thickness direction. Multi-layer extrusion foam moldings,
[7] The resin constituting the foamed layer is one or more resins selected from the group consisting of polystyrene, styrene-acrylonitrile copolymers, styrene-acrylic acid copolymers, and modified polyphenylene ether resins. A multilayer extrusion foamed article according to any one of [1] to [6],
[8] The multilayer extrusion foamed article according to [7], wherein the resin constituting the foamed layer is polystyrene, and
[9] Any one of [1] to [8], wherein one or more hydrocarbons selected from propane, normal butane, isobutane and cyclopentane are contained in the bubbles constituting the foam layer. A multilayer extrusion foamed molded product according to
About.

The effects of the foamed laminated structure of the present invention are as follows.
When a molten resin containing a blowing agent and a molten resin not containing a blowing agent are joined in the thickness direction (vertical direction) under high pressure to produce a laminated molten resin, the molten resin containing the blowing agent is pressurized by a gear pump, By adjusting the resin pressure of the molten resin containing the foaming agent, it becomes possible to adjust the cell diameter of the foam layer constituting the multilayer extrusion foam molded article obtained by releasing the laminated molten resin under atmospheric pressure, The average cell diameter in the thickness direction of the foamed layer can be controlled in the range of 0.07 to 0.25 mm, thereby improving the heat insulation performance.

  Since the above effect can be combined with other conventional techniques aimed at improving the heat insulating properties of the foam molded article, it is expected to provide an extruded foam molded article having an unprecedented excellent heat insulation performance.

FIG. 1 is a schematic view showing a configuration of an apparatus for producing an extruded foam molded body according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a configuration of an apparatus for producing an extruded foam molded body according to another embodiment of the present invention. FIG. 3 is a schematic diagram relating to a laminated structure of an extruded foam molded body according to an embodiment of the present invention. FIG. 4 is a schematic diagram showing the measurement position of the thickness of the extruded foam molded body according to the embodiment of the present invention. FIG. 5 is a schematic view showing the measurement position of the width of the extruded foam molded body according to the embodiment of the present invention.

  As shown in FIGS. 1 and 2, the extrusion foam molded body manufacturing apparatus according to the embodiment of the present invention uses a mold while extruding the heat-plasticized molten resin in the flow direction (see the arrow in the figure). The cross-sectional shape is adjusted and continuously formed.

The manufacturing apparatus includes a foaming extruder 1, a non-foaming extruder 2, a foaming gear pump 3, a non-foaming gear pump 4, a laminating device 5, a laminating doubler 6, a molding die 7, and a molding machine 8. It is a device. (Hereinafter, the lamination device 5 and the lamination doubler 6 are collectively referred to as “multilayer lamination device 9”, and the lamination device 5, the lamination doubler 6 and the molding die 7 are collectively referred to as “multilayer foaming device 10”. In some cases.)
Here, the foaming extruder 1 is an extruder that kneads a thermoplastic resin (added with an additive if necessary), pressurizes and supplies a molten resin containing a foaming agent having a foaming agent press-fitting and cooling mechanism. It is.

  The non-foaming extruder 2 is an extruder that pressurizes and supplies a molten resin that has a kneading mechanism and does not contain a foaming agent.

  The gear pump for foaming 3 is a gear pump for adjusting the resin pressure of the molten resin containing the foaming agent supplied from the foaming extruder 1 and quantitatively supplying the molten resin containing the foaming agent to the multilayer laminating apparatus 9. It is.

  The non-foaming gear pump 4 adjusts the resin pressure of the molten resin not containing the blowing agent supplied from the non-foaming extruder 2 and quantitatively supplies the molten resin not containing the blowing agent to the multi-layer laminating device 9. Gear pump. Note that the non-foaming gear pump 4 is not necessarily an essential device in the present invention, and is preferably used because it is effective for adjusting the resin pressure of a molten resin that does not contain a foaming agent and supplying it quantitatively.

  The laminating apparatus 5 includes at least one molten resin containing a foaming agent supplied from the foaming gear pump 3 and at least one melting resin not containing the foaming agent supplied from the non-foaming gear pump 4 or the non-foaming extruder 2. This is a laminating apparatus that joins the resin in the vertical direction, which is the thickness direction, to obtain a laminated molten resin, and examples thereof include a feed block.

  The lamination doubling device 6 divides the laminated molten resin at the center in the left-right direction, which is the width direction, into two divided laminated resins, and merges these divided laminated molten resins so as to overlap each other. It is an apparatus for making a laminated molten resin. The lamination doubling device 6 is not necessarily an indispensable device in the present invention, and the number of layers can be efficiently increased. Therefore, the lamination doubling device 6 should be used when producing an extruded foam molded body having a large number of layers. Is a preferred device.

  The molding die 7 is a molding die that is doubled by opening the laminated molten resin or the doubled laminated molten resin under atmospheric pressure to vaporize the foaming agent.

  The molding machine 8 is a molding machine that takes a foam molded body and cools it while constraining it in the vertical direction to obtain a final shape.

  In the case of producing an extrusion foamed molded article using the production apparatus shown in FIGS. 1 and 2, the foaming agent in the molten resin containing the foaming agent is foamed in the flow path through which the foaming agent is released under atmospheric pressure. As a result, cell enlargement and low closed cell ratio occur in the foamed layer, and the resulting extruded foamed molded product tends not to exhibit the effect of reducing the thermal conductivity expected by multilayering.

  Therefore, it is necessary to keep the inside of the multilayer foaming apparatus 10 without a pressurizing mechanism such as an extruder at a resin pressure that does not foam in the flow path.

  However, the multi-layer foaming apparatus 10 has a complicated flow path shape and has a long flow path length, so that the pressure loss is large, and the multi-layer foaming apparatus 10 can be obtained only by pressurization by the foaming extruder 1 and the non-foaming extruder 2. 10 tends to be difficult to maintain pressure. It should be noted that operations such as increasing the discharge amount to maintain the pressure in the multilayer foaming apparatus 10, decreasing the resin temperature in the multilayer foaming apparatus 10 and increasing the resin melt viscosity, and narrowing the resin flow path of the molding die 76, etc. When the resin pressure of the foaming extruder 1 and the non-foaming extruder 2 is increased, the foaming agent is unstablely press-fitted, the resin supply is unstable, the extruder is damaged due to overload, and the like. there is a possibility.

  The gear pumps 3 and 4 used in the present invention are classified as constant displacement pumps that can obtain a constant flow rate. The gear pumps 3 and 4 are composed of one drive gear and one free gear; one drive There are a gear 3-row type consisting of a gear and two free gears; a gear planetary type consisting of one drive gear and a plurality of free gears;

As its principle, a certain amount of discharge is secured by the actions (1) to (3).
(1) When the meshing of the gear is released by rotation at the inlet of the gear pump, the gear tooth gap is filled with molten resin.
(2) The molten resin collected in the tooth gap is confined by the casing and the side plate, and moves in the direction of the outlet along the inside of the casing according to the rotation.
(3) When the gear teeth mesh with each other at the outlet, the molten resin is pushed out and discharged by a certain amount.

Therefore, even if there is a slight fluctuation in the resin pressure at the tip portion of the extruder, the fluctuation of the downstream resin pressure is very small because the gear pump absorbs the fluctuation by using the gear pump.
In order to improve the quantitative supply performance by the gear pump, a method of changing the number of rotations of the screw of the extruder and controlling the resin pressure before the gear pump to be constant is preferable.

  The foaming gear pump 3 used in the present invention contains a foaming agent for maintaining the resin pressure in the multi-layer foaming device 10 in addition to the role of quantitatively supplying the molten resin containing the foaming agent to the laminating device 5. It plays a role of increasing the resin pressure of the molten resin to be supplied to the laminating apparatus 5 in a state where pressure fluctuation is suppressed.

  The non-foaming gear pump 4 used in the present invention, in addition to the role of quantitatively supplying a molten resin containing no foaming agent to the laminating device 5, in order to maintain the resin pressure in the multilayer foaming device 10, It plays a role of increasing the resin pressure of the molten resin not included and supplying it to the laminating apparatus 5 in a state where pressure fluctuation is suppressed.

Further, the foamed gear pump 3 is used, and the molten resin containing the foaming agent is laminated by adjusting the viscosity of the molten resin containing the foaming agent, adjusting the amount of the foaming agent, adjusting the resin temperature, or adjusting the discharge amount. It is possible to adjust the resin pressure when supplied to the apparatus 5.
Further, the molten resin not using the foaming agent is used by using the non-foaming gear pump 4 and adjusting the viscosity of the molten resin not containing the foaming agent by adjusting resin, adjusting the plasticizer amount, adjusting the resin temperature, etc., or adjusting the discharge amount. It is possible to adjust the resin pressure when is supplied to the laminating apparatus 5.
As a result, the resin pressure in the multilayer foaming apparatus 10 can be adjusted, and the cell diameter of the foamed layer constituting the extruded foamed article can be controlled.

  The meaning of obtaining an extrusion foamed molded article by the coextrusion method in which a molten resin containing a foaming agent and a molten resin not containing a foaming agent are merged in the thickness direction and released under atmospheric pressure is economical. In addition to such advantages, the non-foamed layer suppresses the intrusion of air into the foamed layer cell, which is caused by the reduced internal pressure of the cells constituting the foamed layer, as the temperature of the molded body decreases immediately after production. This is because high heat insulation is expected.

Furthermore, by adopting a structure in which both sides of the foam layer are covered with the non-foam layer in the thickness direction, the infiltration of air from the outside air into the foam layer cell is suppressed, and the heat insulation performance of the resulting foam is further improved. Further, the meaning of merging in the thickness direction is that it is possible to obtain a structure that easily exhibits the effect of reducing the thermal conductivity expected by multilayering. This is because the heat conductivity of the heat insulating material is measured in the thickness direction of the heat insulating material as defined in JIS A9511. Therefore, the presence of a plurality of non-foamed layers in the thickness direction results in radiation heat transfer between the foam layers. This is because an effect of suppressing gas 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 extrusion foaming molding obtained by making the molten resin containing a foaming agent and the molten resin which does not contain a foaming agent merge in a thickness direction becomes a thing with favorable heat insulation with low heat conductivity.

  On the other hand, when they are merged in the left-right direction, the resulting extruded foamed molded product transfers heat in the non-foamed layer, which has a higher thermal conductivity than the foamed layer (acts as a thermal bridge), so the thermal conductivity is low. It tends to be high and inferior in heat insulation performance.

  The method for joining and laminating each molten resin in a multilayer shape in the multilayer laminating apparatus 9 is not particularly limited, and a method using the laminating apparatus 5, for example, a feed block method generally used in a coextruded film, Multi-manifold method: A laminating apparatus 5 described in Japanese Patent Publication No. Sho 54-23025, Japanese Patent Laid-Open No. 4-278323, etc. is used to create a laminar flow consisting of a plurality of layers, The method of repeating lamination | stacking; after making the some division | segmentation flow as described in Japanese translations of PCT publication No. 2005-523831, Unexamined-Japanese-Patent No. 2004-249520, etc., the method of laminating sequentially is mentioned.

  The temperature of the multilayer laminating apparatus 9 when producing the extruded foam molded body is equal to or less than ± 10 ° C. even if the temperature of the foaming agent-containing molten resin supplied to the multilayer laminating apparatus 9 is different. It is preferable. When the temperature difference is ± 10 ° C. or less, molding processing in an appropriate foaming temperature region is possible, and an extruded foam molded article having a foam layer having a high magnification and a high closed cell ratio can be obtained.

  The pressure in the multi-layer laminating apparatus 9 when manufacturing the extruded foam molded body is set to a pressure at which the foaming agent-containing molten resin supplied to the multi-layer laminating apparatus 9 does not cause foaming in the multi-layer laminating apparatus 9 and the foaming gear pump 3 It is adjusted by the non-foaming gear pump 4. However, the pressure that does not cause foaming in the multilayer laminating apparatus 9 depends on the type of foaming agent, the amount of foaming agent, and the temperature of the foaming agent-containing molten resin, and therefore cannot be set unconditionally.

  In the present invention, the foam molding method using the molding die 7 is not particularly limited. For example, a molding die and a molding roll 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 forming a plate-like foam having a large cross-sectional area can be used.

Regarding the melt-kneading of the constituent resin of the foam layer using the foaming extruder 1,
(I) The thermoplastic resin is mixed with a foaming agent and, if necessary, an additive to be described later, and then heated and melted.
(Ii) One or more kinds selected from the additives described later are mixed with the thermoplastic resin as necessary, and then heated and melted, and the remaining additives described later are liquefied or melted as they are or as necessary. Add and heat mix
(Iii) A thermoplastic resin is mixed with one or more additives selected from the additives described later as necessary, and then a heat-melted composition is prepared, and then the composition and the remaining components are described later. Additives, if necessary, thermoplastic resin mixed again, supplied to the foaming extruder 1 and melted by heating.
The thermoplastic resin and, if necessary, the additives described later are supplied to the heat-melting extruder, and then the foaming agent is added to the thermoplastic resin under high pressure conditions at any 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 5.

  There are no particular limitations on the heating temperature, melt kneading time, and melt kneading means when heating and kneading the thermoplastic resin and an additive such as a foaming agent.

  Although the heating temperature should just be more than the temperature which the thermoplastic resin to be used 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, etc., and thus cannot be generally determined, but the time required for uniformly dispersing and mixing the thermoplastic resin and the foaming agent 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 normal 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 using the non-foaming extruder 2, for example,
(I) The thermoplastic resin is mixed with an additive, which will be described later, if necessary, and then heated and melted.
(Ii) One or more kinds selected from the additives described later are mixed with the thermoplastic resin as necessary, and then heated and melted, and the remaining additives described later are liquefied or melted as they are or as necessary. Add and heat mix
(Iii) A thermoplastic resin is mixed with one or more additives selected from the additives described later as necessary, and then a heat-melted composition is prepared, and then the composition and the remaining components are described later. Additives, if necessary, mix thermoplastic resin again, supply to the extruder and melt by heating.
Etc., a thermoplastic resin and, if necessary, an additive which will be described later are supplied to an extruder, followed by heat-melt kneading. Thereafter, the melt-kneaded product is supplied to the multilayer laminating apparatus 9.

  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 to be used melts, but the temperature difference is within ± 10 ° C. even if it is equal to or different from the set temperature of the multilayer laminating apparatus 9 to which the molten resin is supplied. It is preferable. When the temperature difference is ± 10 ° C. or less, it is possible to obtain a good extruded foamed article having no bubble breakage at the interface portion between the foamed layer and the non-foamed layer and no adhesion failure. 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 extruded foam molded body of the present invention has a structure in which a foam layer is laminated via a non-foam layer in the thickness direction, and the average cell diameter in the thickness direction is controlled in the range of 0.07 to 0.25 mm. By doing, the foaming molding excellent in the heat insulation performance can be obtained.

  As the structure of the extrusion foamed molded product of the present invention, a foamed layer is laminated in the thickness direction of the extruded foamed molded product via a non-foamed layer as shown in FIG. 3 (a): foamed layer / non-foamed layer / foamed layer. It is preferable to have a structure of This is because in the structure in which the foam layer is laminated on both sides of the non-foam layer, the non-foam layer has a larger thickness than the cell thickness of the cell constituting the foam layer. This is because the conductivity reduction effect works effectively. In addition, in a structure in which a foam layer is laminated only on one side of the non-foam layer, such as a non-foam layer / foam layer / non-foam layer, the effect of reducing thermal conductivity due to suppression of radiant heat transfer by the non-foam layer is sufficient. There is a tendency not to develop.

  As the structure of the extrusion foamed molded article of the present invention, it is more preferable that there are a plurality of non-foamed layers such as foamed layer / non-foamed layer / foamed layer / non-foamed layer / foamed layer shown in FIG. . This is because by providing a plurality of non-foamed layers in the thickness direction of the extruded foam molded article, an excellent thermal conductivity reduction effect that cannot be obtained with a single non-foamed layer is exhibited.

  The foam layer constituting the extruded foam molded body of the present invention refers to a layer having a cell structure in which a plurality of cells are bonded by cell walls and cell wall joints (struts). 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 target extruded foam molded article.

  The foamed layer constituting the extruded foamed article of the present invention needs to have a cell structure having an average cell diameter in the thickness direction of 0.25 mm or less, and an average cell diameter in the thickness direction of 0.10 to 0.00. It preferably has a 25 mm cell structure, and more preferably has a cell structure having an average cell diameter in the thickness direction of 0.07 to 0.20 mm.

  A molded body having a cell structure in which the foam layer has a cell structure having an average cell diameter in the thickness direction of 0.25 mm or less is excellent in heat insulation. In addition, when it becomes a bubble structure whose average cell diameter of thickness direction is 0.07 mm or less, the thickness of a bubble wall and a bubble wall coupling | bond part becomes thin, and the radiation suppression effect by a heat ray passing a cell wall and a bubble wall coupling | bond part May be reduced and heat insulation may be deteriorated.

Here, the average cell diameter (A1) in the thickness direction is obtained as follows.
(1) A cross-sectional photograph of the foam layer located in the central portion is taken at a magnification of 20 to 200 times using a microscope, such as a micro high scope or a scanning electron microscope. At this time, the thickness direction is taken in the vertical direction and the extrusion direction is taken in the horizontal direction. The magnification is appropriately selected depending on the bubble diameter.
(2) Three arbitrary 2000 μm straight lines are drawn in the longitudinal direction of the cross-sectional photograph, and the number (X1) of bubbles in contact with the straight lines is measured. The average bubble diameter (A1) in the thickness direction of the bubbles is obtained by the following formula.
A1 [unit: μm] = 2000 × 3 ÷ number of bubbles (X1)

  In the present invention, as a method of controlling the average cell diameter in the thickness direction in the foamed layer in the extruded foamed product, the foaming gear pump 3 and the non-foaming gear pump 4 are used, and the resin selection of the molten resin, the foaming agent is used. It is preferable to adjust by adjusting the resin pressure when the molten resin is supplied to the laminating device 5 by adjusting the viscosity by adjusting the amount, adjusting the amount of plasticizer, adjusting the resin temperature, or adjusting the discharge amount.

As another method for controlling the average cell diameter in the thickness direction of the foam layer,
(A) Nucleating agents represented by inorganic compounds such as silica, talc, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide, titanium oxide, calcium carbonate, sodium hydrogen carbonate, and layered silicates Is added to the styrenic resin and adjusted according to the amount added,
(B) It is adjusted by the screw shape of the extruder, which is a melt-kneading means, the heating temperature, 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. Methods, etc. are also mentioned.

  However, these methods tend to greatly affect the expansion ratio, closed cell ratio, cell flatness (cell diameter in the flow direction / cell diameter in the thickness direction) and the like. There is a tendency to be less convenient.

  On the other hand, in the cell diameter control method by resin pressure control when supplying to the laminating apparatus 5 using the gear pumps 3 and 4, the influence on the expansion ratio, the closed cell ratio, the cell flatness ratio, etc. It is an excellent method that is small compared to the method and that allows easy fine adjustment of the cell diameter.

As described above, the density of the foamed layer in the present invention 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 it is preferably ~65kg / ^{m 3,} more preferably from 20 to 50 kg / ^{m 3,} more preferably 20~40kg / ^{m 3.} When the density of the foamed layer is in the range of 20 to 60 kg / m ³ , a foamed molded article excellent in mechanical properties such as light weight and compressive strength and heat insulation can be obtained.

  The resin constituting the foamed layer of the extruded foamed molding of the present invention (hereinafter sometimes referred to as “foamed layer constituting resin”) is arbitrarily selected from thermoplastic resins that can be extruded and foamed.

Examples of the thermoplastic resin used in the present invention include styrene resins such as polystyrene, styrene-acrylonitrile copolymer, styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid ester copolymer, Vinyl resins such as polymethyl methacrylate, polyacrylonitrile resin, polyvinyl chloride resin; polypropylene, polyethylene, ethylene-propylene copolymer, ethylene-propylene-butene terpolymer, cycloolefin-based (co) polymer Polyolefin resins such as Nylon 6, Nylon 66, Nylon 11, Nylon 12, MXD Nylon, etc .; Polyethylene terephthalate, Polyester resins such as ribylene terephthalate and polyarylate; polycarbonate resins, polyphenylene ether resins, modified polyphenylene ether resins, polyoxymethylene resins, polyphenylene sulfide resins, polyphenylene sulfide resins, aromatic polyether resins, Examples include engineering plastics such as polyether ether ketone resin and liquid crystal resin; and aliphatic polyester resins such as polylactic acid.
These can be used individually or in mixture of 2 or more types.

When a styrene-based resin is used as the foamed layer constituting resin of the extruded foam molded body of the present invention, it is not particularly limited. For example, a styrene homopolymer obtained from only a styrene monomer, a copolymer of styrene monomer and styrene Examples thereof include random, block or graft copolymers obtained from possible monomers or derivatives thereof, post-brominated polystyrene, modified polystyrene such as rubber-reinforced polystyrene, ABS resin, and the like.
These can be used individually or in mixture of 2 or more types.

Examples of the monomer 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 Compounds; diene compounds such as budadiene or derivatives thereof; unsaturated carboxylic acid anhydrides such as maleic anhydride, itaconic anhydride, citraconic anhydride; N-methylmaleimide, N-butylmer N-alkyl substituted maleimide compounds such as imide, N-cyclohexylmaleimide, N-phenylmaleimide, N-4-diphenylmaleimide, N-2-chlorophenylmaleimide, N-4-bromophenylmaleimide, N-1-naphthylmaleimide; Is given.
These can be used individually or in mixture of 2 or more types.

  Among these, as the foam layer-constituting resin of the extruded foam molded body of the present invention, polystyrene, styrene-acrylonitrile copolymer can be obtained because an extruded foam molded body that is easy to extrusion foam molding, lightweight, and excellent in heat insulation can be obtained. Styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid ester copolymer, maleic anhydride-modified polystyrene, styrene-unsaturated dicarboxylic acid anhydride-N-alkyl substituted maleimide copolymer, A styrene resin such as impact-resistant polystyrene, or a vinyl resin such as polymethyl methacrylate or polyvinyl chloride resin; a modified polyphenylene ether resin that is a mixed resin of a polystyrene resin and a polyphenylene ether resin is preferable. Most preferred is a polystyrene homopolymer.

  In addition, for the purpose of adjusting the resin pressure when the foamed layer constituting resin is supplied to the laminating apparatus 5 in a molten state by the foaming gear pump 3, the kind of thermoplastic resin, molecular weight, It is preferable to select a copolymerization component, a copolymerization ratio, and the like.

  The foamed layer of the extrusion foamed molded article of the present invention is obtained by press-fitting a physical foaming agent into a foamed layer-constituting resin in a molten state under high pressure and opening it to a low pressure region.

The physical blowing agent to be injected in the present invention 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, and neopentane; Ethers such as dimethyl ether, diethyl ether, methyl ethyl ether, isopropyl ether, n-butyl ether, diisopropyl ether, furan, furfural, 2-methyl furan, tetrahydrofuran, tetrahydropyran; acetone, methyl ethyl ketone, diethyl ketone, methyl n-propyl ketone, Ketones such as methyl n-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 Alcohol, i-propyl 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, acetic acid Examples thereof include esters such as butyl, amyl acetate, methyl propionate, and ethyl propionate; alkyl halides such as methyl chloride and ethyl chloride; inorganic blowing agents such as nitrogen, air, and carbon dioxide.
These foaming agents can be used alone or in combination 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. Moreover, 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; alkyl halides such as methyl chloride and ethyl chloride are preferred. Furthermore, 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 type foaming agent that is press-fitted into the melted 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 1-10 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 10 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 can be obtained. As a result, characteristics such as light weight and heat insulation are exhibited.

  The pressure when the foaming agent is press-fitted is not particularly limited as long as it is higher than the internal pressure of an extruder or the like.

  In the production of the foamed layer constituting the extruded foam molded body of the present invention, as necessary, flame retardant, flame retardant aid, silica, talc, calcium silicate, wollastonite, kaolin, clay, mica, zinc oxide , Inorganic compounds such as titanium oxide and calcium carbonate, processing aids such as sodium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, stearyl amide compound, phenolic antioxidant, phosphorus stabilizer It is preferable to add additives such as nitrogen-based stabilizers, sulfur-based stabilizers, 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 ris (3,5-di-tert-butyl-4-hydroxybenzyl) benzene, tris (3,5-di-tert-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 diph Amine stabilizers such as nilamine, 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 constituting the extruded foamed molded product of the present invention is equal to the thickness of the extruded foamed molded product and the number of foamed layers in the extruded foamed molded product (number of units composed of foamed layer / non-foamed layer / foamed layer). It is selected as appropriate.

The non-foamed layer constituting the extruded foamed molded article of the present invention refers to a layer having a thickness 1.1 times or more larger than the thicker portion of the bubble wall or bubble wall bonding portion constituting the foam layer. . The density of the non-foamed layer depends on the density of the resin and additives used, but is preferably more than 500 kg / m ³ . The non-foamed layer may contain fewer bubbles than the foamed layer.

  The resin or resin composition constituting the non-foamed layer in the present invention (hereinafter sometimes referred to as “non-foamed layer-constituting resin”) was obtained in order to obtain the desired highly heat-insulated extruded foam molded product. Since it is preferable that the foamed layer and the non-foamed layer of the extruded foamed article are bonded well, it is preferable to select a resin that is compatible with the resin constituting the foamed layer.

The thermoplastic resin having compatibility with the foamed layer-constituting resin 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, nylon 66, polyamide resins such as 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 resins Examples thereof include resins, polyacrylonitrile, polyvinyl alcohol, ethylene-vinyl acetic acid copolymers, polyacrylic acid, polymethyl methacrylate, and thermoplastic phenol resins.
These can be used individually or in mixture of 2 or more types.

  Among these, polystyrene resins, polyolefin resins, polyphenylene ether resins, and modified polyphenylene ether resins are preferred because of excellent compatibility with the foamed layer constituent resin and ease of moldability, and styrene resins are preferred. More preferred.

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, post-brominated polystyrene, modified polystyrene such as rubber-reinforced polystyrene, and ABS resin.
These can be used individually or in mixture of 2 or more types.

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-alkyl-substituted maleimide compounds such as N-cyclohexylmaleimide, N-phenylmaleimide, N-4-diphenylmaleimide, N-2-chlorophenylmaleimide, N-4-bromophenylmaleimide, N-1-naphthylmaleimide; It is done.
These can be used individually or in mixture of 2 or more types.

  In particular, when a styrene resin is used as the non-foamed layer-constituting resin, styrene homopolymer, styrene acrylonitrile copolymer, (meth) acrylic acid copolymer polystyrene, maleic anhydride modified from the viewpoint of compatibility with the foamed layer More preferably, polystyrene, styrene-unsaturated dicarboxylic anhydride-N-alkyl-substituted maleimide copolymer, and high impact polystyrene are used, 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 rosins, rosin derivatives, petroleum resins, terpene resins, phenol resins, rosin phenol resins, ketone resins, etc. Examples thereof include compositions.

  The non-foamed layer-constituting resin is a kind of thermoplastic resin so as to have a desired melt viscosity for the purpose of adjusting the resin pressure when supplied to the laminating device 5 in a molten state by the non-foaming gear pump 4; It is preferable to select a molecular weight, a copolymerization component, a copolymerization ratio, and the like.

  The structure of the non-foamed layer constituting the extruded foam molded body of the present invention is not particularly limited, and any structure of a single layer or multiple layers can be adopted.

  The thickness of the non-foamed layer constituting the extruded foamed molded product of the present invention is the thickness of the extruded foamed molded product and the number of foamed layers in the extruded foamed molded product (number of units comprising foamed layer / non-foamed layer / foamed layer). Is suitably selected according to the range, preferably 10 to 500 μm, more preferably 20 to 300 μm, particularly preferably 30 to 200 μm, and most preferably 40 to 100 μm. 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.

  In the production of the non-foamed layer constituting the extruded foam molded body of the present invention, as necessary, plasticizer, flame retardant, flame retardant aid, silica, talc, calcium silicate, wollastonite, kaolin, clay, Inorganic compounds such as mica, zinc oxide, titanium oxide, calcium carbonate, processing aids such as sodium stearate, magnesium stearate, barium stearate, liquid paraffin, olefin wax, stearylamide compound, phenolic antioxidant, It is preferable to add additives such as phosphorous stabilizers, nitrogen stabilizers, sulfur stabilizers, light-resistant stabilizers such as benzotriazoles and hindered amines, colorants such as antistatic agents and pigments.

  Among these additives, the plasticizer does not disturb the flow at the resin joining interface during the production of the extruded foamed molding of the present invention, and the melt viscosity of the non-foamed layer-constituting resin contains a foaming agent. Since it works effectively when making adjustments close to the melt viscosity of the resin, it also works effectively to control the resin pressure when the resin is supplied to the laminating device 5 using the non-foaming gear pump 4 by adjusting the melt viscosity of the resin by the addition amount. Therefore, it is preferable to add.

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), butyl benzyl phthalate (BBP), phthalic acid esters such as phthalic acid混基ester _(C 6 _{~C 11);} dioctyl adipate (DOA), diisononyl adipate (DINA), dialkyl adipate (C6,8,10 ) (610A), dialkyl adipate _{(C 7, C 9) (} 79A) Azerai Dioctyl acid (DOZ) dibutyl sebacate (DBS), dioctyl sebacate (DOS), tricresyl phosphate (TCP), tributyl acetylcitrate (ATBC), epoxidized soybean oil (ESBO), trioctyl trimellitic acid (TOTM), Non-phthalic acid esters such as chlorinated paraffin, and the like.

  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 preferred is 3 to 12 parts by weight, and most preferred is 4 to 10 parts by weight. 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. .

  The thickness of the extruded foam molded body 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 impart 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 of the extruded foamed product of the present invention at 20 ° C. is
0.034 W / m · K (0.0292 kcal / m · hr · ° C.) or less is preferable, 0.032 W / m · K (0.0275 kcal / m · hr · ° C.) or less is more preferable, and 0.030 W / m. · K (0.0258 kcal / m · hr · ° C) or less is particularly preferable.

  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 extruded foam molded body of the present invention has various uses, for example, building materials such as floor materials, wall materials, and roof materials, heat insulation materials for cold cars, vehicle bumpers, from the viewpoint of its excellent light weight and heat insulation properties. It can be suitably used for automobile members such as automobile ceiling materials and civil engineering members such as antifreezing agents for ground.

  Next, the present invention will be described in detail based on examples, but the present invention is not limited to such examples.

  Evaluation methods for Examples and Comparative Examples are as follows.

(1) Extruded foam molding dimensions [unit: mm]
Thickness: As shown in Fig. 4, the thickness of the three extruded foam molded products sampled at different times was measured at the central portion (midpoint in the width direction) in the width direction (horizontal direction orthogonal to the extrusion direction). The average value was calculated.
Width: For three extruded foam molded products sampled at different times, as shown in FIG. 5, the width at the center in the thickness direction (the middle point in the thickness direction) was measured, and the average value was calculated.
Identification of the central portion in the thickness direction: A portion located at a value of 1/2 of the thickness from the upper surface and a value of 1/2 of the width from the left side was defined as the central portion.

(2) Density of extruded foam molding [unit: kg / m ³ ]
For three extruded foam moldings sampled at different times, the foam density was measured according to the method described in JIS K7222-1999 "Foamed plastics and rubber-Apparent density measurement", and the average value was calculated. did.

(3) Thermal conductivity [unit: W / m · K]
The thermal conductivity of the obtained extrusion foamed molded article was measured using a thermal conductivity measuring device [manufactured by Eihiro Seiki Co., Ltd., 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 surface was removed, the width direction was 25 mm, the length direction was 25 mm, and the thickness direction was from the center in the width direction. It cuts out with the thickness as it is, analyzed and measured the amount of air in the extrusion foaming molding using a gas chromatograph [manufactured by Shimadzu Corporation, GC-14A], and calculating the average value, The partial pressure of air was determined.

(5) Average cell diameter in the thickness direction (A)
Extruded foamed molded article was cut out and observed at a magnification of 50 times using a microscope [manufactured by Keyence Co., Ltd., Digital Microscope VHX-900] for the central part in the thickness direction, and the method described in the specification text. The average cell diameter (A) in the thickness direction was determined.

Example 1
[Method for producing molten resin containing foaming agent]
Polystyrene [manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.0 g / 10 min] 100 parts by weight, talc [manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z] 0.5 weight Parts, calcium stearate [manufactured by Sakai Chemical Industry Co., Ltd., trade name: SC-P] 0.3 parts by weight, liquid paraffin [manufactured by Nippon Oil Corporation, trade name: polybutene LV-50] 0.1 parts by weight. The mixture was dry blended to obtain a styrene resin composition. The styrenic resin composition was supplied at 39.8 kg / hr 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 230 ° C., and a styrenic resin is used as a foaming agent near the tip of the first extruder (the side connected to the second extruder). Styrenic resin composition in which 4.0 parts by weight of i-butane [manufactured by Mitsui Chemicals Co., Ltd.] and 4.0 parts by weight of dimethyl ether [manufactured by Taiyo Liquefied Gas Co., Ltd.] are melted with respect to 100 parts by weight of the resin composition. Press fit into.
At this time, the resin pressure at the tip of the first extruder was 10.5 MPa, while the press-fitting pressure of the foaming agent was 11.5 MPa.
In the second extruder connected to the first extruder, after the resin temperature of the molten resin containing the foaming agent is cooled to 130 ° C., the foam is provided at the front end of the second extruder and temperature-controlled at 130 ° C. A gear pump [manufactured by Pla Giken Co., Ltd., GP74 / 74-100; discharge capacity of 100 cc per rotation] was supplied while adjusting the rotational speed of the first extruder so that the resin pressure was 5.0 MPa. The rotation speed of the foaming gear pump was set to 7.2 rpm, and the molten resin containing the foaming agent was divided into four, and then a feed block for two types of 7-layer multi-layers provided at the tip of the foaming gear pump [Pura Giken Co., Ltd. The resin pressure was 6.8 MPa.
[Method for producing molten resin containing no foaming agent]
Low heat-resistant polystyrene [manufactured by PS Japan Co., Ltd., trade name: SC004, MFR = 6.5 g / 10 min] 100 parts by weight of dimethyl phthalate [manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP] ] 4.0 parts was added and extruded at a resin temperature of 190 ° C. and a discharge rate of 36.2 Kg / hr with a twin screw extruder [manufactured by OH Machinery Co., Ltd .: TEK, 45 mm diameter twin screw extruder] and pre-master batched did.
The obtained resin was melt-kneaded by heating to 150 ° C. with an extruder having a diameter of 50 mm [manufactured by Pla Giken Co., Ltd.], and a gear pump temperature adjusted to 150 ° C. [manufactured by Kyowa Finetech Co., Ltd., HDSM-45G- 20 × 1; discharge capacity of 20 cc per rotation], while adjusting the screw speed of the extruder so that the resin pressure becomes 10 MPa. The rotation speed of the gear pump was set to 8 rpm, the flow was divided into three, and the resin pressure was 19.1 MPa and the discharge amount was 10.1 kg / hr to the two-type seven-layer multi-layer feed block.

[Method for Producing Extruded Foamed Molded Body by Melting Melted Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
In the feed block for the two types of 7-layer multi-layers, the temperature of which is adjusted to 130 ° C., the molten resin not containing the blowing agent (three layers) is divided into four in the thickness direction under a pressure of 6.3 MPa. The molten resin containing the foaming agent thus formed was joined at a thickness of 5.2 mm / 1.4 mm / 5.2 mm / 1.4 mm / 5.2 mm / 1.4 mm / 5.2 mm, respectively. .
Multilayer flow doubling device having a function similar to the function of dividing and laminating the multi-layered flow described in Japanese Patent Publication No. Sho 54-23025 and temperature-controlled at 130 ° C. [Pura Giken Co., Ltd. ]. Thereafter, a multilayer flow merged at a resin pressure of 3.0 MPa is pushed out into the atmosphere from a die lip having a rectangular cross section with a thickness direction of 2.2 mm and a width direction of 80 mm that is temperature-controlled at 100 ° C. It is sandwiched between the devices on which the conveyor is arranged and taken up, and is a rectangular parallelepiped shape having a thickness of 21.5 mm and a width of 208 mm. An extruded foam molded article having a 13-layer structure of foamed layer / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
The density of the extruded foamed product obtained was 35.3 kg / m ³ , the average cell diameter in the thickness direction of the foamed layer was 0.12 mm, and the thermal conductivity at an air partial pressure of 51 kPa was 0.0282 W / m · K.

(Example 2)
[Method for producing molten resin containing foaming agent]
Polystyrene [manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.0 g / 10 min] 100 parts by weight, talc [manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z] 0.5 weight Parts, calcium stearate [manufactured by Sakai Chemical Industry Co., Ltd., trade name: SC-P] 0.3 parts by weight, liquid paraffin [manufactured by Nippon Oil Corporation, trade name: polybutene LV-50] 0.1 parts by weight. The mixture was dry blended to obtain a styrene resin composition. The styrenic resin composition was supplied at 39.8 kg / hr 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 230 ° C., and a styrenic resin is used as a foaming agent near the tip of the first extruder (the side connected to the second extruder). Styrenic resin composition in which 4.0 parts by weight of i-butane [manufactured by Mitsui Chemicals Co., Ltd.] and 4.0 parts by weight of dimethyl ether [manufactured by Taiyo Liquefied Gas Co., Ltd.] are melted with respect to 100 parts by weight of the resin composition. Press fit into.
At this time, the resin pressure at the tip of the first extruder was 10.4 MPa, while the press-fitting pressure of the foaming agent was 11.8 MPa.
In the second extruder connected to the first extruder, after the resin temperature of the molten resin containing the foaming agent is cooled to 130 ° C., the foam is provided at the front end of the second extruder and temperature-controlled at 130 ° C. A gear pump [manufactured by Pla Giken Co., Ltd., GP74 / 74-100; discharge capacity of 100 cc per rotation] was supplied while adjusting the rotational speed of the first extruder so that the resin pressure was 5.0 MPa. The rotation speed of the foaming gear pump was set to 7.2 rpm, and the molten resin containing the foaming agent was divided into four, and then a feed block for two types of 7-layer multi-layers provided at the tip of the foaming gear pump [Pura Giken Co., Ltd. The resin pressure was 7.0 MPa.
[Method for producing molten resin containing no foaming agent]
Low heat-resistant polystyrene [manufactured by PS Japan Co., Ltd., trade name: SC004, MFR = 6.5 g / 10 min] 100 parts by weight of dimethyl phthalate [manufactured by Daihachi Chemical Industry Co., Ltd., trade name: DMP] ] 4.0 parts was added and extruded at a resin temperature of 190 ° C. and a discharge rate of 36.2 Kg / hr with a twin screw extruder [manufactured by OH Machinery Co., Ltd .: TEK, 45 mm diameter twin screw extruder] and pre-master batched did.
The obtained resin was melt-kneaded at a resin temperature of 150 ° C. using an extruder with a diameter of 50 mm [manufactured by Pla Giken Co., Ltd.], and the screw rotation speed was 20.0 rpm so that the discharge amount was 10.0 kg / hr. Then, the flow was divided into three and supplied to the feed block for the two kinds of seven-layer multilayer lamination at a resin pressure of 17.8 MPa.

[Method for Producing Extruded Foamed Molded Body by Melting Melted Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
In the feed block for the two types 7-layer multi-layer lamination temperature-controlled at 130 ° C., the molten resin (3 layers) containing no blowing agent is divided into four in the thickness direction under a pressure of 6.6 MPa. The molten resin containing the foaming agent thus formed was joined at a thickness of 5.2 mm / 1.4 mm / 5.2 mm / 1.4 mm / 5.2 mm / 1.4 mm / 5.2 mm, respectively. .
Multilayer flow doubling device having a function similar to that of dividing and laminating the multi-layered flow described in Japanese Patent Publication No. Sho 54-23025 and temperature-controlled at 130 ° C. (manufactured by Pla Giken Co., Ltd.) ). Thereafter, a multilayer flow merged at a resin pressure of 3.1 MPa is pushed out into the atmosphere from a die lip having a rectangular cross section with a thickness of 2.4 mm and a width of 80 mm that is temperature-controlled at 100 ° C. It is sandwiched between the devices on which the conveyor is arranged and is taken up, and has a rectangular parallelepiped shape with a thickness of 21.7 mm and a width of 212 mm. An extruded foam molded article having a 13-layer structure of foamed layer / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
The density of the obtained extruded foamed molded product was 34.8 kg / m ³ , the average cell diameter in the thickness direction of the foamed layer was 0.14 mm, and the thermal conductivity at an air partial pressure of 51 kPa was 0.0286 W / m · K.

(Comparative Example 1)
[Method for producing molten resin containing foaming agent]
Polystyrene [manufactured by PS Japan Co., Ltd., trade name: G9401, MFR = 2.0 g / 10 min] 100 parts by weight, talc [manufactured by Hayashi Kasei Co., Ltd., trade name: TALCAN PAWDER PK-Z] 0.5 weight Parts, calcium stearate [manufactured by Sakai Chemical Industry Co., Ltd., trade name: SC-P] 0.3 parts by weight, liquid paraffin [manufactured by Nippon Oil Corporation, trade name: polybutene LV-50] 0.1 parts by weight. The mixture was dry blended to obtain a styrene resin composition. The styrenic resin composition was supplied at 39.8 kg / hr 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 styrene resin composition supplied to the first extruder is melt-kneaded at a resin temperature of 230 ° C., and styrene is used as a foaming agent near the tip of the first extruder (the side connected to the second extruder). Styrene resin composition in which 4.0 parts by weight of i-butane [manufactured by Mitsui Chemicals Co., Ltd.] and 4.0 parts by weight of dimethyl ether [manufactured by Taiyo Liquefaction Gas Co., Ltd.] are added to 100 parts by weight of the resin resin composition. Pressed into the object. At this time, the resin pressure at the tip of the first extruder was 14.2 MPa, while the press-fitting pressure of the foaming agent was 15.3 MPa.
In the second extruder connected to the first extruder, after the resin temperature is cooled to 130 ° C., it is divided into four, and two types of molten resin containing a foaming agent are provided at the tip of the second extruder A 7-layer multi-layer feed block [manufactured by Pla Giken Co., Ltd.] was supplied at a resin pressure of 7.0 MPa.
[Method for producing molten resin containing no foaming agent]
3. Polystyrene [PS Japan Co., Ltd., trade name: SC004, MFR = 6.5 g / 10 min] 100 parts by weight of dimethyl phthalate [Daihachi Chemical Industry Co., Ltd., trade name: DMP] as a plasticizer 0 part by weight was added, and extruded with a twin screw extruder (One Machinery Co., Ltd .: TEK, twin screw extruder with a diameter of 45 mm) at a resin temperature of 190 ° C. and a discharge amount of 36.2 kg / hr, which was previously masterbatched. .
The obtained resin was melt kneaded at a resin temperature of 150 ° C. using an extruder with a diameter of 50 mm [manufactured by Pla Giken Co., Ltd.], and the screw rotation speed was adjusted to 20.Kg/hr. The pressure was set to 0 rpm, the flow was divided into three, and the resin block was supplied to the feed block for the two kinds of seven-layer multilayer lamination at a resin pressure of 16.8 MPa.

[Method for Producing Extruded Foamed Molded Body by Melting Melted Resin Containing Foaming Agent and Molten Resin Not Containing Foaming Agent in Thickness Direction]
In the feed block for the two types of 7-layer multi-layer laminated at a temperature of 130 ° C., four layers of molten resin (three layers) containing no blowing agent are flowed in the thickness direction under a pressure of 6.5 MPa. The molten resin containing the foaming agent was joined to each other at a thickness of 5.2 mm / 1.4 mm / 5.2 mm / 1.4 mm / 5.2 mm / 1.4 mm / 5.2 mm.
Multilayer flow doubling device having a function similar to the function of dividing and laminating the multi-layered flow described in Japanese Patent Publication No. Sho 54-23025 and temperature-controlled at 130 ° C. [Pura Giken Co., Ltd. ]. Thereafter, the joined multi-layer flow is pushed out into the atmosphere at a resin pressure of 3.0 MPa from a die lip having a rectangular cross section with a thickness of 1.4 mm and a width of 80 mm adjusted to 100 ° C. It is sandwiched between devices placed and taken up, and has a rectangular parallelepiped shape with a thickness of 24.2 mm and a width of 212 mm, foam layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer / foam layer / non-foam layer / foam An extruded foam molded article having a 13-layer structure of layer / non-foamed layer / foamed layer / non-foamed layer / foamed layer was obtained.
The density of the extruded foamed product obtained was 38.0 kg / m ³ , the average cell diameter in the thickness direction of the foamed layer was 0.27 mm, and the thermal conductivity at an air partial pressure of 51 kPa was 0.0293 W / m · K.

In Examples 1 and 2 using the foaming gear pump, the resin pressure in the multilayer extrusion foaming apparatus is kept constant without excessively narrowing the die lip height to 2.2 to 2.4 mm due to the pressure increasing effect of the foaming gear pump. (For example, 3.0 MPa or more), the average cell diameter in the thickness direction of the foamed layer can be reduced, and an extruded foam molded article having a low thermal conductivity can be obtained.
On the other hand, in Comparative Example 1, since the foaming gear pump is not used (and the non-foaming gear pump is not used), in order to keep the resin pressure in the multilayer extrusion foaming apparatus at a constant pressure (for example, 3.0 MPa or more), die slip The height needs to be extremely narrowed to 1.4 mm, the average cell diameter in the thickness direction of the foamed layer is increased, and the obtained extruded foamed product has a high thermal conductivity.

1. 1. Foaming extruder 2. Non-foaming extruder 3. Foam gear pump 4. Non-foaming gear pump Laminating apparatus 6. 6. Stacking doubler 7. Molding die8. Molding machine 9. Multilayer laminating apparatus 10. Multi-layer foaming device 11. Foam layer 12. Non-foamed layer 13. 13. Thickness measurement position of extruded foam molding Width measurement position of extruded foam

Claims (9)

A flow of a laminated molten resin obtained by merging at least one molten resin containing a blowing agent pressurized by a gear pump and at least one molten resin not containing a blowing agent in a vertical direction that is a thickness direction under high pressure. It is a multilayer extrusion foamed molded article obtained by releasing it under atmospheric pressure while extruding in a direction, adjusting the shape of a constant cross section with a mold and continuously molding it,
The multilayer extruded foam has a structure in which a foam layer is laminated in the thickness direction via a non-foam layer, and the foam layer is composed of bubbles having an average cell diameter of 0.25 mm or less in the thickness direction. A multilayer extrusion foamed molded product characterized by that. Obtained by merging at least one molten resin containing a blowing agent pressurized by a gear pump and at least one molten resin not containing a blowing agent pressurized by a gear pump in a vertical direction that is a thickness direction under high pressure. A multilayer extruded foam obtained by releasing the laminated molten resin under atmospheric pressure while extruding it in the flow direction, adjusting the shape of the cross section with a mold and continuously molding the molded resin,
The multilayer extruded foam has a structure in which a foam layer is laminated in the thickness direction via a non-foam layer, and the foam layer is composed of bubbles having an average cell diameter of 0.25 mm or less in the thickness direction. A multilayer extrusion foamed molded product characterized by that. The multilayer extrusion foamed molded article according to claim 1 or 2, wherein the density of the multilayer extruded foam molded article is 20 to 65 Kg / m ³ . Wherein the density of said multi-layer extrusion foaming body is 20~40Kg / m ^3, multilayer extrusion foam molding according to claim 1 or 2.   5. The multilayer extruded foamed article according to claim 1, wherein an average cell diameter in the thickness direction of the foamed layer is 0.07 to 0.25 mm.   The multi-layer extrusion according to any one of claims 1 to 5, wherein the extruded foam-molded product has a plurality of the structures in which a foam layer is laminated via a non-foam layer in the thickness direction. Foam molded body.   The resin constituting the foamed layer is one or more resins selected from the group consisting of polystyrene, styrene-acrylonitrile copolymer, styrene-acrylic acid copolymer and modified polyphenylene ether resin. The multilayer extrusion foamed molded article according to any one of claims 1 to 6.   The multilayer extrusion foamed molded product according to claim 7, wherein the resin constituting the foamed layer is polystyrene. The one or more types of hydrocarbons chosen from propane, normal butane, isobutane, and cyclopentane are contained in the bubble which comprises the said foaming layer, The any one of Claims 1-8 characterized by the above-mentioned. Multi-layer extrusion foam molding.

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