JP2004034559A - Method for manufacturing extrusion foamed composite - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an extrusion foamed composite having a core material of good uniformity of foamed cells, good closed cell property and high expansion ratio. <P>SOLUTION: A foamable resin 10 for a foamed core material is extruded from the first die 2 of a first extruder 1, while a skin material 30 is extruded from the second die 31 of a second extruder 3, foaming the foamable resin 10 for the foamed core material to form a foamed core material 100. The skin material 30 is covered over the surface of the foamed core material 100, guided to a cooling sizing die 4 and is cooled to be shaped. Thus, a foamed composite 5 obtained by covering the skin material 30 over the outer periphery of the foamed core material 100 is extrusion-molded. The foamable resin 10 for the foamed core material 10 is ejected into the inside of the skin material 30 from the resin extrusion nozzle 25 of the first die, after the skin material 30 starts being cooled with the cooling sizing die 4. <P>COPYRIGHT: (C)2004,JPO

Description

【図面の簡単な説明】
【図１】実施例１にかかる押し出し発泡複合体の成形装置の断面説明図。
【図２】実施例１にかかる押し出し発泡複合体の成形装置のにおける，樹脂押出ノズル及び表皮材押出ノズルの正面図。
【図３】実施例１にかかる押し出し発泡複合体の成形装置の全体平面図。
【図４】実施例１において得られた押し出し発泡複合体の断面斜視図。
【図５】実施例１において得られた押し出し発泡複合体の拡大図。
【図６】実施例３における，本発明にかかる，樹脂押出ノズルと表皮材押出ノズルの位置関係を示す説明図。
【図７】実施例３における，従来例にかかる，樹脂押出ノズルと表皮材押出ノズルの位置関係を示す説明図。
【符号の説明】
１．．．第１押出機，
１０．．．発泡芯材用発泡性樹脂，
１００．．．発泡芯材，
２．．．第１ダイス，
２５．．．樹脂押出ノズル，
２８．．．表皮材押出ノズル，
３．．．第２押出機，
３０．．．表皮材，
５．．．押し出し発泡複合体，[0001]
【Technical field】
The present invention relates to a foam composite used in the fields of civil engineering and building materials, for example, concrete forms, walls, floors, ceilings, shelves, etc. The present invention relates to a method for producing an extruded foam composite.
[0002]
[Prior art]
Conventionally, a method has been known in which a thermoplastic resin containing a foaming agent is extruded from an extruder, foamed to form a foamed core material, and a skin material is coated on the outer periphery of the foamed core material to form a foamed composite. I have. Extrusion foaming is advantageous in terms of production volume and production cost since foams can be produced continuously, and is widely used.
[0003]
However, it is difficult to form a thick foam core material into a desired shape by extrusion foaming and to cover the foam core material with a skin material.
That is, even if the foamable resin for the foamed core containing the foaming agent is accurately extruded into a plate shape or the like, the extruded foamable resin for the foamed core is foamed immediately after exiting the die of the extruder. Therefore, the extruded material swells three-dimensionally and largely deforms and curves from the desired shape. Accordingly, in order to obtain the desired shape of the foam core material thus obtained, the shape is corrected by cutting or hot pressing and used. Therefore, the manufacturing process of the foamed composite is complicated and the material is wasteful.
[0004]
In order to eliminate such complications and waste, a long body of foamed plastic molded in advance is placed in an extruder, and the skin material is covered with a die to obtain a desired shape, and the surface strength and bending strength of the composite are reduced. (For example, JP-A-8-336876).
However, this method has a drawback in that the number of steps is two and the production cost is high because a foam molded in advance is used.
[0005]
Japanese Patent Application Laid-Open No. 4-282237 discloses a method for producing a foam with a skin layer, in which the foam is extruded and cooled to a low temperature with a homing die in order to obtain a skin layer on the surface of the foam.
However, in this method, it is difficult to obtain a skin layer having a very small skin layer and a thickness of 0.5 mm or more.
[0006]
Further, in order to increase the expansion ratio, a method of increasing the amount of a foaming agent added to the foamable resin for the foamed core material or further adding water together with the foaming agent (Japanese Patent Application Laid-Open Nos. Hei 7-276470 and Hei 8- 216220).
However, even if the amounts of the foaming agent and water are excessively increased, there is a limit in improving the expansion ratio, and only a 2-3 times expansion ratio can be obtained.
[0007]
Further, Japanese Patent Application Laid-Open No. 2-194922 discloses a method in which the inside is a foamed resin layer and the entire outer periphery is covered with a non-foamed resin skin material. However, in this method, the temperature of the foamed resin rises near the temperature of the skin material. As a result, the foamed resin is softened, its melt viscosity decreases, and the resin pressure in the die also decreases. Therefore, even if an attempt is made to obtain a foamed core material having a high expansion ratio, the uniformity and independence of the cells of the foamed core material become insufficient, and a satisfactory foamed composite cannot be obtained.
[0008]
[Problem to be solved]
The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a method for producing an extruded foamed composite having a foamed core material having high uniformity of foam cells, good closed cells, and a high expansion ratio. Things.
[0009]
[Means for solving the problem]
The present invention provides a method for extruding a foaming resin for a foamed core material comprising a thermoplastic resin containing a foaming agent from a first die of a first extruder, while a skin comprising a non-foaming thermoplastic resin or a low foaming thermoplastic resin. Extruding the material from the second die of the second extruder,
The foamable resin for foamed core material is foamed to form a foamed core material, and the skin material is coated on the surface of the foamed core material, and then immediately led to a cooling sizing die to be cooled and shaped into a desired shape. A method of continuously extruding a foamed composite comprising the above-mentioned skin material on the outer periphery of a foamed core material made of the foamable resin for a foamed core material,
The foamable resin for the foamed core material is cooled by the cooling sizing die after the skin material discharged from the skin material extrusion nozzle of the second die starts to cool the skin material from the resin extrusion nozzle of the first die. This is a method for producing an extruded foam composite, which is discharged to the inside.
[0010]
In the present invention, after the skin material discharged from the skin material extrusion nozzle begins to be cooled by the cooling sizing die, the foamable resin for the foamed core material containing the foaming agent is discharged inside the skin material. Therefore, the foamable resin for the foamed core material comes into contact with the skin material, which has already slightly solidified in temperature and has started to solidify, and the foamable resin for the foamed core material is hardly affected by the heat of the skin material.
Therefore, it is possible to prevent the melt viscosity of the foamable resin for the foamed core material, which is foaming inside the skin material, from decreasing and the foaming pressure from decreasing.
Therefore, the foamable resin for the foamed core material that foams inside the skin material hardly undergoes heat shrinkage.
[0011]
Therefore, it is possible to obtain an extruded foamed composite having a foamed core material having a high foaming ratio of, for example, 10 to 50 times, and excellent uniformity of foam cells and good closed cell properties.
[0012]
As described above, according to the present invention, it is possible to provide a method for producing an extruded foamed composite having a foamed core material having a high foaming ratio and excellent uniformity and closed cell properties of the foamed cells.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
In the present invention, the foamable resin for a foamed core material is extruded from a resin extrusion nozzle of a first die provided in a first extruder. The skin material is extruded from a skin material extrusion nozzle of a second die provided in the second extruder. On the other hand, the foamable resin for the foam core material is ejected from the resin extrusion nozzle to the inside of the skin material that has already been extruded and has started to be cooled by the cooling sizing die, and then foams to become a foam core material.
The foam core material comes into contact with the inner wall surface of the skin material, and both are fused. As a result, an extruded foam composite comprising the foam core material and the skin material coated on the outer periphery thereof is obtained.
[0014]
The cooling sizing die is a cooling die for obtaining an extruded foam composite having a desired shape.
In addition, cooling shaping to a desired shape means that while the skin material is cooled by a cooling sizing die, the degree of adhesion of the foam composite to the cooling sizing die is increased by the foaming pressure of the foamable resin for the foam core material. This refers to shaping while cooling.
[0015]
A non-foaming or low-foaming thermoplastic resin is used as the skin material. The non-foamable thermoplastic resin does not use a foaming agent, and the low-foamable thermoplastic resin uses a small amount of a foaming agent.
Examples of the thermoplastic resin include styrene resins such as polystyrene, acrylic butadiene styrene (ABS) resin, various polyethylenes, polypropylene resins, polyolefin resins such as a copolymer of polypropylene and α-olefin, and polyvinyl chloride. There are resins, vinyl acetate resins, various nylon resins, various acrylic resins, polycarbonate resins, and mixed resins thereof.
In addition, fillers such as talc, calcium carbonate, mica and the like can be added to these resins, and various pigments can be added.
[0016]
The method of the present invention is particularly effective for a resin obtained by adding the above filler to a styrene resin or a polypropylene resin. In this case, the rigidity is high and the cost is relatively low. Further, in order to improve the appearance of the product, it is preferable to add a small amount of a foaming agent to the above-mentioned skin material and use it as a low-foaming skin material.
[0017]
Further, as the foamable resin for the foam core material, a thermoplastic resin containing a foaming agent is used. As the thermoplastic resin, the same thermoplastic resins as those described above for the skin material can be used.
Examples of the foaming agent include volatile foams such as aliphatic hydrocarbons such as propane, n-butane, i-butane, pentane and hexane, and cycloaliphatic hydrocarbons such as cyclobutane, cyclopentane and cyclohexane. Agents, azodicarbonamide, azobisisobutylnitrile, sodium bicarbonate and the like.
Further, air, carbon dioxide, nitrogen and the like can be used as the inorganic foaming agent. Further, these foaming agents can be appropriately mixed and used.
[0018]
Examples of the nucleating agent used to obtain a more uniform foam cell include polyethylene wax, ethylenebisamide, hexabromocyclododecane, and a methacrylic acid lower alkyl ester-based polymer containing 5% by weight or more of methacrylic acid lower alkyl ester units. At least one selected from organic nucleating agents and inorganic nucleating agents such as talc and silica. These nucleating agents are contained in an amount of preferably 0.2 to 5% by weight, more preferably 0.4 to 2.0% by weight, based on the foamable resin for the foamed core material.
[0019]
The amount of the foaming agent added to the foamable resin for the foamed core material is preferably 3 to 15% by weight. As a method of adding the volatile foaming agent, the foamed resin beads contained therein can be used, and for example, the foaming agent can be injected in an extruder. The adjustment of the magnification of the foam can be freely changed depending on the amount of the foaming agent added, the diameter of the nozzle, the rotation speed of the extruder, the temperature, and the take-up speed.
If a gap is provided between the outlet of the foamable resin for the foam core material and the outlet of the skin material, a foam core material having a higher expansion ratio can be obtained.
[0020]
Next, it is preferable that the resin extrusion nozzle of the first die is provided forward of the position of the skin material extrusion nozzle of the second die in the extrusion direction.
In this case, while the skin material discharged from the skin material extrusion nozzle of the second die is being cooled by the cooling sizing die adjacent to the skin material extrusion nozzle, the resin extrusion nozzle of the first die is cooled. More foamable resin for foamed core material can be discharged. Therefore, the uniformity and independence of the foam cells can be further enhanced.
[0021]
Next, the temperature of the skin material at a position corresponding to the position of the resin extrusion nozzle of the first die is equal to or higher than the temperature of the foamable resin for the foamed core material discharged from the resin extrusion nozzle by 50 ° C. It is preferably within the range (claim 3).
[0022]
In this case, it is possible to obtain an extruded foam composite having an even higher expansion ratio, good uniformity of foam cells, and good closed cell properties.
If the temperature difference obtained by subtracting the temperature of the foamable resin for the foam core from the skin temperature exceeds 50 ° C., the temperature of the foam and the foamable resin for the foam core ejected from the resin extrusion nozzle is set to The difference is large.
As a result, the foamable resin for the foamed core material is affected by the heat of the skin material, the melt viscosity of the foaming resin for the foamed core material being foamed decreases, the foaming cells shrink, and the foaming pressure rises. hard. Therefore, it is difficult to sufficiently obtain a high expansion ratio, uniformity of foam cells, and closed cell properties.
[0023]
On the other hand, if the temperature of the skin material at the above position is lower than the temperature of the foamable resin for the foamed core material (less than the above), the foamable resin for the foamed core material discharged from the resin extrusion nozzle is foamed. In some cases, the foamed core material and the skin material are difficult to fuse with each other. Therefore, it is difficult to obtain an extruded foam composite having a high bonding strength between the foam core material and the skin material.
[0024]
Next, the foamable resin for the foamed core material discharged from the resin extrusion nozzle preferably contains 0.1 to 10% by weight of water based on the foamable resin for the foamed core material ( Claim 4).
In this case, it is possible to obtain an extruded foamed composite having a higher expansion ratio, excellent uniformity of foamed cells, and excellent closed cell properties.
[0025]
When the above water content is less than 0.1% by weight, it is difficult to obtain a high expansion ratio because there is little vaporization and foaming due to water.
On the other hand, if it exceeds 10% by weight, the effect of adding water is relatively small, and the foam may shrink.
The water content is more preferably 0.1 to 2% by weight.
[0026]
Next, the foamable resin for the foamed core material is composed of 75 to 97.8% by weight of a polystyrene resin, 2 to 20% by weight of a foaming agent, and 0.2 to 5% by weight of a nucleating agent. It is preferably a thermoplastic resin (claim 5).
In this case, the polystyrene resin is a general-purpose resin that is relatively inexpensive in raw materials, has high holding power for the blowing agent, and has good moldability. Further, by using the nucleating agent, the uniformity of the foam cell is improved, the expansion ratio is increased, and the rigidity per basis weight and cost are also advantageous.
[0027]
If the amount of the polystyrene resin is less than 75% by weight, there is a problem that the foaming becomes too high and the strength becomes weak. On the other hand, if it exceeds 97.8% by weight, there is a problem that the expansion ratio is low and the weight cannot be sufficiently achieved.
[0028]
On the other hand, if the amount of the foaming agent is less than 2% by weight, a high expansion ratio cannot be obtained, while if it exceeds 20% by weight, the expansion ratio becomes too high, resulting in a foam core material having low strength. In addition, there is a problem that gas is formed between the skin material and the foamed core material due to the excess foaming gas, so that the skin material and the foamed core material are not easily fused.
Further, if the nucleating agent is less than 0.2% by weight, it is difficult to achieve uniformity of the foamed cells, while if it exceeds 5% by weight, the uniformity of the foamed cells is not improved, which is economically disadvantageous. Preferably, the content is 1 to 4% by weight.
[0029]
Next, the foamable resin for the foamed core material is extruded from a plurality of resin extrusion nozzles provided in the first die and foamed to form a foamed core material, and the entire foamed core material is covered with the skin material. Is preferred.
In this case, the foamable resin for the foam core material is extruded from each of the first dies, and the foamed state becomes more uniform, so that a foamed composite in a foamed state with less variation as a whole can be obtained.
[0030]
Next, the skin material comprises a main component consisting of 70 to 30% by weight of a styrene-based thermoplastic resin and 30 to 70% by weight of an olefin-based thermoplastic resin, and a thermoplastic elastomer of 1 to 100% by weight of the main component. It is preferable to mix 10% by weight.
[0031]
In this case, the use of an olefin-based thermoplastic resin improves the chemical resistance, which is a drawback of the styrene-based thermoplastic resin, and the addition of a thermoplastic elastomer improves the compatibility with each other, thereby improving the chemical resistance. Products with excellent heat resistance and appearance can be obtained.
[0032]
If the styrene-based thermoplastic resin exceeds 70% by weight, chemical resistance and heat resistance may be deteriorated. On the other hand, if it is less than 30% by weight, poor fusion with the foamed core material may occur.
If the content of the olefin-based thermoplastic resin is less than 30% by weight, there is a problem that the chemical resistance and heat resistance are deteriorated. There's a problem.
[0033]
On the other hand, if the content of the thermoplastic elastomer is less than 1% by weight, the compatibility between the olefin-based thermoplastic resin and the styrene-based thermoplastic resin becomes poor, and there is a problem of poor appearance. On the other hand, if it exceeds 10% by weight, there is a problem that the rigidity of the skin material is reduced, and the rigidity of the foamed composite is reduced.
[0034]
Next, the thermoplastic elastomer is preferably styrene-butadiene-styrene (SBS) or styrene-ethylene-butadiene-styrene (SEBS).
In this case, a foam composite having good compatibility and excellent appearance of the skin material can be obtained.
[0035]
【Example】
Example 1
A method for manufacturing an extruded foam composite according to an embodiment of the present invention will be described with reference to FIGS.
First, as shown in FIGS. 4 and 5, the extruded foam composite 5 to be obtained in the present example has a plurality of foamed core materials 100 formed by foaming foamable resin for a foamed core material, and the surroundings thereof. It comprises a skin material 30 made of a non-foamed thermoplastic resin or a low-foamable thermoplastic resin which is integrally coated.
Also, the plurality of foamed core materials 100 have the coatings 15 in the adjacent portions fused to each other. That is, each expanded core material 100 is composed of a large number of expanded particles 101, and the periphery thereof is surrounded by the coating 15. The films 15 are fused to each other. The film 15 is formed when the film 15 is discharged from a resin extrusion nozzle during molding.
[0036]
Next, in producing the foam composite 5, as shown in FIGS. 1 to 3, a foaming resin 10 for a foaming core material made of a thermoplastic resin containing a foaming agent is supplied to the first extruder 1. The first extruder 3 extrudes a skin material 30 made of a non-foamed thermoplastic resin or a low-foamable thermoplastic resin from a second die 31 of a second extruder 3.
Then, the foamable resin 10 for foamed core material is foamed to form the foamed core material 100, and the surface material 30 is coated on the surface of the foamed core material 100, and then immediately led to the cooling sizing die 4. By cooling and shaping into a desired shape, an extruded foam composite 5 in which the outer skin material 30 is coated on the outer periphery of the foamed core material 100 made of the foamable resin for foamed core material 10 is continuously extruded.
[0037]
After the skin material 30 discharged from the skin material extrusion nozzle 28 of the second die 31 is started to be cooled by the cooling sizing die 4, the foamable resin 10 for foam core material is extruded from the resin die of the first die 2. It is discharged from the nozzle 25 to the inside of the skin material 30.
Further, as shown in FIG. 1, the resin extrusion nozzle 25 of the first die 2 is provided forward of the position of the skin material extrusion nozzle 28 of the second die 31 in the extrusion direction. That is, the opening end of the resin extrusion nozzle 25 of the first die 2 is located forward of the opening end of the skin extrusion nozzle 28 of the second die 31.
[0038]
Hereinafter, these will be described in detail.
First, as shown in FIGS. 1 to 3, a foam molding apparatus for carrying out the extrusion foam molding includes a first die 2 and a first die 2 for feeding a foamable resin 10 for a foam core into the first die 2. An extruder 1 and a second extruder 3 for feeding the skin material 30 are provided. A cooling sizing die 4, a cooling water tank 45, and a take-off machine 46 for the extruded foam composite 5 are sequentially disposed in front of the first die 2 (FIG. 3).
[0039]
As shown in FIGS. 1 to 3, the first die 2 extrudes and discharges the foamable core material foamable resin 10, and has five resin extrusion nozzles 25. And a guide portion 24 that guides the guide 10. The first die 2 is provided with a manifold that divides these into five parts according to the resin extrusion nozzles 25 described above.
As shown in FIG. 2, a skin material extrusion nozzle 28 for forming a skin material is provided around the five resin extrusion nozzles 25 so as to surround the five resin extrusion nozzles 25 as a skin material outlet. .
[0040]
An annular rectangular gap 361 is provided between the first die 2 provided with the resin extrusion nozzle 25 and the skin material extrusion nozzle 28 which is an outlet of the skin material.
Further, the second extruder 3 has a flow path 32 for guiding the skin material 30 to the skin material extrusion nozzle 28.
[0041]
Next, the manufacturing method will be described in detail with reference to FIGS.
First, the skin material 30 is extruded from the second extruder 3, is spread annularly in the flow path 32, is uniformly diverted in thickness on both upper and lower side surfaces, is extruded from the skin material extrusion nozzle 28 and is discharged, and It is sent out along the inner wall.
[0042]
On the other hand, the foamable resin 10 for foamed core material extruded from the first extruder 1 is guided to the first die 2. The space portion 21 of the first die 2 is a coat hanger-shaped portion for uniformly spreading the molten resin in the width direction, and the center portion has a narrower resin passage gap than the outer peripheral portion. The foamable resin for foam core material 10 flows into the guide portion 24 at the front part, is guided to each resin extrusion nozzle 25, and finally from the resin extrusion nozzle 25 provided at the tip of the first die 2 to the inside of the skin material 30. And extruded.
As described above, the foamable resin for foam core material 10 is extruded from the skin material extrusion nozzle 28, and is extruded into the skin material 3 that has begun to be cooled by the cooling sizing die 4.
[0043]
Further, the foamable resin 10 for the foamed core material extruded from the five resin extrusion nozzles 25 foams inside the skin material 30 extruded as described above to become the foamed core material 100, and these five foamed core materials are formed. The respective coatings 15 of the core material 100 are fused together. Then, the skin material 30 covers the entire outer periphery of the five foamed core materials 100, and the extruded foamed composite 5 in which these are fused is obtained (FIGS. 4 and 5).
[0044]
The foaming of the foamable core foaming resin 10 is performed in the skin material 30 in the form of a rectangular box formed by the skin material extrusion nozzle 28. The extruded foam composite 5 is taken off by a caterpillar type take-up machine 46 through a cooling water tank 45 inside the cooling sizing die 4.
The cooling sizing die 4 has a cavity having a rectangular cross section, that is, a molding space for molding the extruded foam composite 5. The cooling sizing die 4 has a cooling water passage 41 for cooling.
[0045]
The temperature of the skin material 30 at a position corresponding to the position of the resin extrusion nozzle 25 of the first die 2 is equal to or lower than the temperature of the foamable resin 10 for the foamed core material discharged from the resin extrusion nozzle 25. It is in the temperature range of 50 ° C. higher.
[0046]
As described above, as shown in FIGS. 4 and 5, the extruded foam composite 5 including the five foamed core materials 100 and the skin material 30 integrally covering the periphery thereof is obtained.
Each of the foamed core members 100 has a coating 15 on its outer periphery, and adjacent portions of the coating 15 are fused to each other. The outer periphery of the foam core material 100 and the skin material 30 are fused.
Further, a small triangular gap 16 is formed between the adjacent coating 15 and the skin material 30.
[0047]
In this example, after the skin material 30 discharged from the skin material extrusion nozzle 28 starts to be cooled by the cooling sizing die 4, the foamable resin 10 containing a foaming agent inside the skin material 30 contains a foaming agent. Is discharged. Therefore, the foamable resin for foam core material 10 comes into contact with the skin material 30 which has already slightly cooled down and has begun to solidify, and the foamable resin for foam core material 10 is hardly affected by the heat of the skin material 30. .
[0048]
For this reason, it is possible to prevent the melt viscosity of the foamable resin 10 for the foamed core material that is foaming inside the skin material 30 from decreasing and the foaming pressure from decreasing.
Therefore, the foam core material 100 located inside the skin material 30 hardly undergoes thermal contraction.
Therefore, it is possible to obtain an extruded foam composite 5 having a foam core material 100 having a high foaming ratio of, for example, 10 to 50 times, and excellent uniformity of foam cells and closed cells.
[0049]
An annular rectangular gap 361 is provided between the die 2 provided with the resin extrusion nozzle 25 and the skin material extrusion nozzle 28 which is an outlet of the skin material 30 (FIGS. 1 and 2). Therefore, the heat of the skin material 30 in the second die 31 is not transmitted to the foamable resin 10 for the foam core in the first die, so that a foam core material having a high expansion ratio can be obtained.
Further, the surface of the excellent foamed core material is coated with the skin material almost simultaneously with the molding and foaming of the foamed core material. Therefore, the fusion between the skin material and the foam core material and the fusion between the foam core material and the foam core material can be effectively performed.
[0050]
Example 2
Next, specific examples and comparative examples of the present invention will be described.
An acrylic butadiene styrene (ABS) resin (Technopolymer Co., Ltd., ABS resin 606) was used as the skin material.
[0051]
As the foamable resin for the foamed core material, a polystyrene resin impregnated with 7% by weight of butane as a foaming agent (Mitsubishi Chemical Foam Plastic Co., Ltd., Styropol JPE-151) was used. Further, 1.2 wt% of talc was mixed as a nucleating agent with respect to 100 wt% of polystyrene resin.
[0052]
The temperature of the skin material 3 at the outlet of the skin material extrusion nozzle 28 of the second die 31 was 185 ° C., and the temperature of the foamable resin for the foam core material at the outlet of the resin extrusion nozzle 25 of the first die 2 was 140 ° C.
The temperature of the skin material 30 at a position corresponding to the position of the resin extrusion nozzle 25 of the first die 2 is based on the temperature (140 ° C.) of the foamable core material foamable resin 10 discharged from the resin extrusion nozzle 25. Was 185 ° C., which is 45 ° C. higher.
That is, the temperature difference (ΔT) between the skin material and the foamable resin for the foamed core material at the above position was 45 ° C.
Water at 20 ° C. was passed through the cooling water passage 41 of the cooling sizing die 4 to cool the extruded foam composite. The take-up speed of the extruded foam composite 5 was 1 m / min.
[0053]
The obtained extruded foam composite 5 had an extremely good appearance, the average thickness of the skin material 30 was 1 mm, the foamed state of the foamed core material 100 was uniform, and the average foaming ratio was 25 to 35 times. Further, the skin material 30 and the foam core material 100 were fused, and the fusion between the five foam core material films 15 was sufficient.
[0054]
Example 3
In this example, as shown in FIGS. 6 and 7, the positions of the skin material extrusion nozzle 28 and the resin extrusion nozzle 25 are changed, and the amount of water added to the foamable resin 10 for the foam core is changed to change the extruded foam composite. Body manufactured.
That is, first, as shown in FIG. 6, the resin extrusion nozzle 25 is positioned at a position (length L) ahead of the skin material extrusion nozzle 28 in the extrusion direction, and the extruded foam composite 5 is formed in the same manner as in Example 2. Manufactured.
In this example, the length L was set to 50 mm.
In addition, water as a foaming agent was added at various ratios to the foamable resin for the foamed core material, and the relationship between the change in the water content and the expansion ratio of the foamed core material in the obtained extruded foamed composite was determined. It was measured.
[0055]
As shown in FIG. 7, the position of the skin material extrusion nozzle 28 and the position of the resin extrusion nozzle 25 were set to the same position (length L = 0), and an extruded foam composite was manufactured in the same manner as above. .
Table 1 shows the results.
[0056]
From Table 1, it can be seen that when the resin extrusion nozzle 25 is positioned 50 mm ahead of the skin material extrusion nozzle 28, a higher expansion ratio can be obtained than when both are positioned at the same position.
This can also be said when no water is added (water 0% by weight). In addition, when water is added, a high expansion ratio can be obtained, and the effect is particularly large when the water content is 0.1 to 2% by weight.
[0057]
[Table 1]

[Brief description of the drawings]
FIG. 1 is an explanatory sectional view of an apparatus for forming an extruded foam composite according to a first embodiment.
FIG. 2 is a front view of a resin extrusion nozzle and a skin material extrusion nozzle in the extruded foam composite molding apparatus according to the first embodiment.
FIG. 3 is an overall plan view of an extruded foam composite molding apparatus according to the first embodiment.
FIG. 4 is a sectional perspective view of the extruded foam composite obtained in Example 1.
FIG. 5 is an enlarged view of the extruded foam composite obtained in Example 1.
FIG. 6 is an explanatory view showing a positional relationship between a resin extrusion nozzle and a skin material extrusion nozzle according to the present invention in a third embodiment.
FIG. 7 is an explanatory view showing a positional relationship between a resin extrusion nozzle and a skin material extrusion nozzle according to a conventional example in Embodiment 3.
[Explanation of symbols]
1. . . First extruder,
10. . . Foamable resin for foam core,
100. . . Foam core material,
2. . . The first die,
25. . . Resin extrusion nozzle,
28. . . Skin material extrusion nozzle,
3. . . Second extruder,
30. . . Skin material,
5. . . Extruded foam composite,

Claims (5)

A foaming resin for a foamed core material made of a thermoplastic resin containing a foaming agent is extruded from a first die of a first extruder, while a skin material made of a non-foamed thermoplastic resin or a low foamable thermoplastic resin is extruded into a second material. Extruded from the second die of the extruder,
The foamable resin for foamed core material is foamed to form a foamed core material, and the skin material is coated on the surface of the foamed core material, and then immediately led to a cooling sizing die to be cooled and shaped into a desired shape. A method of continuously extruding a foamed composite comprising the above-mentioned skin material on the outer periphery of a foamed core material made of the foamable resin for a foamed core material,
The foamable resin for the foamed core material is cooled by the cooling sizing die after the skin material discharged from the skin material extrusion nozzle of the second die is cooled, and then the skin material is discharged from the resin extrusion nozzle of the first die. A method for producing an extruded foamed composite, comprising discharging to the inside. 2. A method for manufacturing an extruded foam composite according to claim 1, wherein the resin extrusion nozzle of the first die is provided forward of the position of the skin material extrusion nozzle of the second die in the extrusion direction. The temperature of the skin material at a position corresponding to the position of the resin extrusion nozzle of the first die according to claim 1 or 2, is equal to or lower than the temperature of the foamable resin for the foamed core material discharged from the resin extrusion nozzle. A method for producing an extruded foam composite, which is in a temperature range higher by 50 ° C. 4. The foamable resin for a foamed core material discharged from the resin extrusion nozzle according to any one of claims 1 to 3, wherein the foamable resin for a foamed core material contains 0.1 to 10% by weight of water based on the foamable resin for the foamed core material. A method for producing an extruded foam composite, comprising: The foamable resin for a foamed core material according to any one of claims 1 to 4, wherein the polystyrene-based resin is 75 to 97.8% by weight of a polystyrene resin, 2 to 20% by weight of a foaming agent, and 0.2 to 5% by weight of a nucleating agent. Wherein the skin material is a styrene-based thermoplastic resin.

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