JPH06238788A - Foamed styrene resin sheet laminated body preparation thereof - Google Patents

Abstract

PURPOSE:To avoid a foreign substance layer on a joint of each foamed sheet by a method wherein the viscosity of a foamable molten substance obtd. by incorporating a volatile foaming agent in a styrene resin is made in such a way that the viscosity of the molten substance coming to the inside of a laminated body is at most 1.1 times of that coming to the outside thereof and under this condition, both flows are joined together and are extruded from a nozzle and are foamed outside of the nozzle. CONSTITUTION:Foamed molten substances are prepared by pressing a volatile foaming agent such as an aliph. hydrocarbon in a styrene resin and extruding the mixture by means of extruders 1 and 2 and they are joined together by means of a joint flow adaptor 21 and are extruded from a nozzle 22. In this case, the melt viscosity of the intermediate layer of the foamable molten substance from the extruder 1 positioned on both sides of the intermediate layer from the extruder 2 is made in such a way that the viscosity of the outer side thereof is in the range of 1.1-0.5 of that of the inner side and are extruded from the nozzle. Therefore, when they are joined together in the nozzle 22, they are adhered into accurate layers and are foamed out of the nozzle 22 and as foaming is performed at the same density even at the joint of each layer, no layer of foreign substance with low foaming occurs at the joint.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a styrene resin foam sheet laminate and a method for producing the same.

[0002]

Foamed sheets of styrenic resins have been made by extrusion foaming. Foam sheets made by extrusion foam always had a high-density skin on the surface. This is because when the expandable styrene resin is extruded from the die, the surface of the extruded resin comes into contact with air and is cooled, so that the surface cannot be foamed at a high magnification like the inside.

Lamination of foam sheets is necessary, for example, to make a foam whose surface differs in color from the interior. In such a case, a method has heretofore been adopted in which foamed sheets are separately formed by extrusion foaming and then the sheets are bonded together. As described above, when the foamed sheets are separately formed and then bonded to each other, a different layer is always formed at the bonded portion, which causes inconvenience.

More specifically, to bond the foamed sheets, there are a typical method of fusing by heat and a method of bonding with an adhesive. Among these, in the method of fusing by heat, even if peeling and peeling the skin from the surface of the foam sheet, a high-density skin is generated on the surface by heating for fusion, and further inside the skin close to the skin. Since the secondary foaming causes the bubbles to coarsen, a remarkable heterogeneous layer is formed as a whole at the bonding time. Also,
In the method of adhering with an adhesive, when a material having a large dissolving power for the foam sheet is used as the adhesive, the adhesive dissolves the surface of the foam sheet to form a high-density layer on the surface. When a material having a weak dissolving power for the foamed sheet was used, the adhesive formed a new layer. Further, when the pieces were pasted while leaving a high-density skin on the surface, a non-uniform layer was more prominently formed at the joint. Therefore, in any case, a remarkable heterogeneous layer was formed at the bonded portion.
For this reason, the conventional foamed sheet laminate not only has a poor appearance but also has a poor feel, and further has a problem in processing.

A coextrusion method is used when a laminate is made from a sheet that is not foamed. Coextrusion means that thermoplastic resins with different compositions kneaded by different extruders are separately put into one die, and each resin is molded into a sheet shape, and the obtained sheet-shaped material is made into the same die. It is a method of merging and adhering inside, and extruding as a laminated body from one die. This method is theoretically applicable to foamed sheets, but it was difficult to actually apply it to foamed sheets.

The reason why the coextrusion method is difficult to apply to the production of a foamed sheet is that the resin contains a foaming agent and is a foamable composition. The foamable composition is
This is because, unlike the case where only the thermoplastic resin is used because it contains the foaming agent, when the sheet-shaped melts are merged in the die, the sheet-shaped melts are easily mixed with each other. For example, a foamable composition has a large change in melt viscosity depending on the type and content of a foaming agent contained therein, and a small change in melt viscosity causes a large change in foaming rate. In extreme cases, foaming or foaming occurs. Because there are none. Moreover, no specific study has been made on how to coextrude the foamable composition.

[0007]

The inventor of the present invention has attempted to make a laminate of foamed sheets made of a styrene resin and having no foreign matter layer at the seam of each foamed sheet. Moreover, the inventor has attempted to make such a laminate of foam sheets by coextrusion.

[0008]

Means for Solving the Problems The present inventor has found that when the foamable composition is merged in the die by the above-described coextrusion method to form a laminate, the foamable composition does not get mixed and is constant. It has been found that the melt viscosity of the foamable composition is an important factor for joining the layers as they are to form a desired laminate.

In general, the melt viscosity of a foamable composition varies greatly even if the same resin is used, depending on the type of the additive added to the resin, especially the type of the foaming agent contained therein, and the content of the additive. is there. Further, the melt viscosity largely changes depending on the temperature of the foamable composition and the temperature of the passage in the die. However, in the co-extrusion, the temperature will be small because they pass through one and the same die. Therefore, in coextrusion, the melt viscosity can be adjusted mainly by the relationship between the resin and the additive. Therefore, the inventor has decided to adjust the melt viscosity by the relationship between the resin and the additive, especially the foaming agent.

The present inventor uses a styrene resin as a resin when the melts of expandable resins having different compositions are combined in one die to form a laminate, and the laminate is formed in a resin passage in the die. If a foaming agent is added to each resin composition so that the viscosity of the melt coming to the outside of the resin will be lower than the viscosity of the melt coming to the inside, the joints of the foamed sheets will be formed orderly by coextrusion, It has been found that the formation of a foreign layer is not formed in the eyes. As a result of further tests, the viscosity of the melt coming to the outside does not have to be lower than the viscosity of the melt coming to the inside as long as a styrene resin is used as the resin. It was found that a foamed laminate having no heterogeneous layer as described above can be obtained when the viscosity is 1.1 times or less of the viscosity of the melt coming inward. The present invention has been completed based on such knowledge.

This application includes a manufacturing method invention and a product invention. Among them, the invention of the manufacturing method, the thermoplastic resins having different compositions are melted in different extruders, respectively, are separately put into one die and molded into a sheet shape, and are joined in the same die, In a method for producing a resin laminate in which three layers are integrated, a styrene resin is selected as a resin, and an aliphatic hydrocarbon, an alicyclic hydrocarbon having a boiling point lower than the softening point of the styrene resin,
Halogenated aliphatic hydrocarbon, carbon dioxide or nitrogen is press-fitted into the molten resin in the extruder to give the resin a foaming property to form a foaming melt, and the viscosity of the resin melt coming to the outer wall of the laminate is adjusted to Characterized by extruding from the above die as a laminated body in which the resin melts are fused together to make the viscosity of 1.1 times or less of the viscosity of the resin melt coming to the claw, and foaming outside the die. Is.

Further, the invention of the object is directed to the styrene resin foam sheet laminate obtained by the above-mentioned method. The laminate is characterized in that there is no heterogeneous layer such as a high-density layer at the joint of each layer, and all the internal layers are uniformly foamed and adhered. That is, the laminated body is a laminated body of foamed sheets in which at least three layers of styrenic resin foamed sheets having different compositions are laminated and integrated, and each layer is uniformly foamed inside the laminated body. The seams of the above layers are also characterized in that each layer is uniformly foamed and solidly integrated like the rest.

In the present invention, a styrene resin is used. The styrene-based resin is not limited to a homopolymer of styrene or a derivative thereof, a copolymer of styrene or a derivative thereof,
And a graft polymer. Here, the styrene derivative is, for example, α-methylstyrene, chlorostyrene, or the like. The styrene or styrene derivative copolymer is, for example, a copolymer of styrene or α-methylstyrene and acrylonitrile, butadiene, methyl acrylate, maleic anhydride, methacrylic acid or methacrylic acid ester. The graft polymer is, for example, one obtained by graft-polymerizing styrene to an acrylonitrile / butadiene copolymer. In these copolymers or graft polymers, it is necessary that styrene or a styrene derivative accounts for 50% by weight or more. These homopolymers, copolymers and graft polymers may be used as a mixture of these.
It can also be used as a mixture with another resin, for example, a compatible resin such as polyphenylene ether. Further, these styrene-based resins may be collected products of defective products formed in a molding process such as extrusion molding and pressure molding, or collected products such as food containers used in the market.

In the present invention, styrene resins having different compositions are used. Needless to say, the case where the composition is different includes the case where the styrene resin itself is different, but the case where the styrene resin itself is the same but the dyes, pigments and other additives are only different It also includes. That is, the meaning of different compositions refers to resin compositions that cannot be kneaded by the same single extruder.

An extruder is used in the present invention. The extruder is
This is a mechanism in which a rotatable screw is installed in a barrel that can be heated, and styrene resin is melted by heating and the styrene resin is extruded from a die attached to the tip of the barrel. Although extruders having one screw and two screws are often used, in the present invention, it is preferable to use one screw, that is, a single screw extruder.

In the present invention, the foaming agent is pressed into the styrene resin melted in the extruder. For that purpose, by providing a pressure inlet of the foaming agent in the middle of the barrel that constitutes the extruder,
The foaming agent is pressed in from there. The resin melted by press-fitting the foaming agent is given foamability. The foamable melt is then cooled to a temperature suitable for foaming. An extruder is preferably used for this cooling. Therefore, in the present invention, it is preferable to use a tandem extruder as generally used, that is, an extruder in which two extruders are vertically connected to each other, for forming the foamable melt.
In the tandem extruder, the first extruder melts the resin to press-in the foaming agent, and the second extruder cools the expandable melt to the proper foaming temperature, after which the expandable melt is extruded from the die. To be said.

In the present invention, resins having different compositions are melted by different extruders to form a foamable melt. For example, one tandem extruder is used to make a red foamable melt and another is used to make a colorless foamable melt.
One tandem extruder is used. Thus, it is necessary to use as many extruders as the number of resins having different compositions.

In the present invention, since resin compositions having different compositions are extruded, it is necessary to use plural series of extruders, but only one die is used. To this end, the expandable melts made in several series are all placed separately in the same die and initially sheeted separately. However, what is formed into a sheet is then joined in the same die to form a laminated body. Such bases have already been used to make non-foamed resin laminates. The die used in the present invention is basically the same as that used for laminating non-foamed resin.

Up to now, it has been necessary to stack the non-foamed resin.
Different types of bases have been used. One is called a flat die, and the other is called a circular die. The flat die has a structure in which the resin forming each layer is formed into a flat plate shape, which is merged and extruded as a flat plate-shaped laminated body. Since the flat die has a fan shape that spreads out earlier, it is also called a fan die. On the other hand, the circular die has a structure in which the resin forming each layer is formed into a cylindrical shape with a common axis, and the combined resin is merged and extruded as a cylindrical laminated body. In the present invention, either of the two types of die can be used, and the method using a circular die is preferred among them.

When a circular die is used, it is preferable to use a confluent adapter between the extruder and the die. The confluent adapter receives the foamable melts sent from a plurality of extruders from different inlets, and first makes each melt into a cylindrical or cylindrical shape with a common axis, and then the outlets. It is a unit in which a columnar or cylindrical shape is joined to form an integral laminated body. The merging adapter is designed to be sent to the mouthpiece after being made into a laminated body in this way.

Further, in the present invention, it is preferable to attach a melt pump, that is, a gear pump for transporting the melt at a constant rate, between the extruder and the die or the merge adapter. This is because the use of this pump allows the foamable melt from the extruder to be always sent at a constant rate to the die or the joining adapter.

The present invention differs from the case of laminating non-foamed resin in that the styrene resin contains a foaming agent and is made into a foamable melt. A volatile foaming agent is used as the foaming agent. Volatile foaming agent is a gas or liquid with a boiling point lower than the softening point of the resin, and dissolves in the molten resin under pressure, but because of its low solubility, it volatilizes from the molten resin under normal pressure. It is a gas or liquid with

The foaming agent that can be used in the present invention is
Aliphatic hydrocarbons, alicyclic hydrocarbons, halogenated aliphatic hydrocarbons, carbon dioxide and nitrogen. As the aliphatic hydrocarbon, propane, normal butane, isobutane, normal pentane, isopentane, neopentane and the like can be used. As the alicyclic hydrocarbon, cyclopentane, cyclohexane or the like can be used. Examples of the halogenated aliphatic hydrocarbon include 1,1-difluoroethane, 1,1,1,2-tetrafluoroethane, 1-chloro-1,1-difluoroethane and 2,2-dichloro-
1,1,1-trifluoroethane, 1-chloro-1,
2,2,2-tetrafluoroethane, methyl chloride and the like can be used. These may be used alone or in combination. Of these, preferred blowing agents are aliphatic hydrocarbons, alicyclic hydrocarbons and halogenated aliphatic hydrocarbons.

The above-mentioned volatile type foaming agent has the property of lowering the melt viscosity of the styrene resin.
That is, the greater the press-in amount of the foaming agent, the lower the melt viscosity of the styrene resin. Moreover, the rate of decrease in viscosity is a value peculiar to each foaming agent. For example, aliphatic hydrocarbons greatly reduce the melt viscosity of styrene-based resins even when they are pressed into styrene-based resins in small amounts, but nitrogen does not significantly reduce the melt viscosity when they are pressed-in in small amounts. .

According to the present invention, a plurality of expandable melts having a specific relationship are defined based on the melt viscosity of the expandable melt produced by press-fitting a foaming agent into a melt of styrene resin. The greatest feature is that they are merged within the base. More specifically, the greatest feature is that the viscosity of the foamable melt that comes to the outer wall of the laminate is 1.1 times or less than the viscosity of the foamable melt that comes to the inner wall of the laminate. .
The value of 1.1 times is a value found by the present inventor by accumulating laminated foaming experiments using a styrene resin.

In the present invention, the viscosity of the expandable melt is used as a reference, but the viscosity is generally called apparent melt viscosity. The viscosity of the expandable melt which is the standard in this invention does not reverse depending on the composition as long as it is based on the same temperature and pressure even if the temperature and the pressure change to some extent. It may be measured under pressure. However, the method based on this inventor is as follows.

A base 100 having a structure as shown in FIG. 1 is prepared, and the base is attached to the tip of a foam extruding device into which a foaming agent can be pressed. The base 100 is a melt of expandable styrene resin entering from an inlet 101 and has a diameter of 5 mm.
It is designed to be extruded from the outlet 103 through the passage 102. At this time, the extrusion rate Q is 100 sec ⁻¹ (shear rate Q = 4420 cm) when the shear rate r in the passage 102 is 100.
³ / hr, when the density of 1.0g / cm ³ 4.42Kg /
The temperature of the extruder is controlled so that the temperature of the melt is 200 ° C., and the temperature of the die is also controlled at 200 ° C.

As data, the extrusion rate Q (cm ³ / se
c), pressure loss ΔP (L in the middle of a circular tube with a diameter of 0.5 cm)
The pressure difference between the pressure gauge attached with a distance of 5 cm and the pressure gauge Gr / cm ² ) is obtained. The data obtained is used to obtain the shear rate and apparent melt viscosity using the Newtonian equation in a circular tube below. Shear rate r = 32Q / πD ³ sec ⁻¹ Apparent melt viscosity μa = πgD ⁴ ΔP / 128LQ Poise The density of the molten resin is calculated from the specific volume curve of each resin.

The expandable melt may contain various additives as additives in addition to the styrene resin and the foaming agent. For example, it may contain a coloring agent such as a dye or a pigment, a nucleating agent such as talc or calcium carbonate or a bubble adjusting agent, an antistatic agent, an antiaging agent, a stabilizer and the like. However, strictly speaking, the above-mentioned melt viscosity should be a value for those to which these additives are added, but for additives other than the foaming agent, the addition amount is not as large as that of the foaming agent, Further, since the ability to change the melt viscosity of the resin is small, this can be approximately ignored.

Based on the value of the apparent viscosity thus obtained, the melt viscosity of the resin composition coming to the outer shell of the laminate is 1.1 times or less than the melt viscosity of the resin composition coming to the inner shell. It is the greatest feature of the present invention that the relationship between the styrene resin and the foaming agent is adjusted and used.

Of these, the melt viscosity of the resin composition that comes to the outer shell of the laminate is preferably 1.1 to 0.5 times the melt viscosity of the resin composition that comes to the inner shell, and more preferably 1. The range is from 0.0 to 0.7 times.

[0032]

According to the method of the present invention, a styrene resin is selected as the resin, and an aliphatic hydrocarbon, an alicyclic hydrocarbon or a halogenated aliphatic having a boiling point lower than the softening point of the styrene resin is selected as the foaming agent. Since the foaming agent is selected from hydrocarbons, carbon dioxide and nitrogen and used to press-fit into the styrene resin melted in the extruder, a foamable melt can be easily prepared. The desired melt viscosity of the thus obtained foamable melt can be easily obtained by adjusting the type and amount of the foaming agent to be press-fitted. Then, the styrenic resin compositions having different compositions are melted in different extruders, put into one die and molded into a sheet, and at least three layers in the same die are joined and laminated. When forming a sheet, the viscosity of the foamable melt that comes to the outer shell of the laminate is made to be 1.1 times or less the viscosity of the foamable melt that comes to the inner shell. It becomes an accurate layer and adheres without cluttering. For this reason, it is possible to obtain a uniformly foamed laminated body having no foreign material layer by extruding the laminated body from the die and foaming it outside the die. In this way, the advantage of the present invention is great in that a laminate comprising a foam sheet of a styrene resin can be obtained all at once.

Further, the laminated body of the styrene resin foam sheet thus obtained has at least 3 layers of styrene resin foam sheets having different compositions, which are integrated into one body, and each layer is uniform inside the laminated body. In the seam of each of the layers, the same density as that of the remaining portion of each layer is obtained. That is,
There is no formation of a high-density layer at the joint between the layers as in the case of the laminates so far, and there is no foreign matter layer at the joint between the layers. Therefore, the laminate according to the present invention has a good appearance, a good feel, and a foreign substance layer is not present, and thus it is easy to process. In addition, the resulting laminate is typically 0.3-0.0.
It has a density of 4 g / cm ³ and is therefore generally suitable for use as a foam. Further, since it is composed of at least three layers, it is possible to use a recycled product of the used styrene resin for the intermediate layer, and there is an advantage that the resin can be recovered and used. In particular, by adding a modifier such as a styrene / butadiene copolymer to the recycled product, a laminate similar to that using a new material can be obtained. From these points, the laminate according to the present invention has great utility value.

[0034]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples. In the following, simply "parts" means "parts by weight".

[0035]

Example 1 In this example, the apparatus schematically shown in FIG. 2 was used to form an intermediate layer of the expandable melt extruded from the extruder 1, and the expandable melt extruded from the extruder 2 was formed. The objects were located on either side of the intermediate layer, resulting in a three-layer foam sheet laminate.

As the extruder 1, there was used a tandem type foaming extruder in which an extruder having a diameter of 50 mm was used as a first extruder, and a second extruder having a diameter of 65 mm was attached to the first extruder. A mixture of 100 parts of polystyrene resin (made by Asahi Kasei Corp., polystyrene 683, melt index 2.8) and 0.6 part of talc powder was supplied to the extruder 1, melted, and then foamed from the middle of the first extruder. Isobutane as an agent
5 parts (0.43 mol / 1 Kg of resin) were pressed in and kneaded well, and cooled in the second extruder so that the temperature of the foamable melt became 170 ° C. at the outlet of the second extruder. This foamable melt was heated at 200 ° C. and r = 10 using the apparatus shown in FIG.
When the melt viscosity was measured under the condition of ⁰ sec ^-1 , the melt viscosity was 8.0 × 10 ³ poise.

As the extruder 2, an extruder having a diameter of 65 mm was used. 1. A masterbatch containing a pink pigment in the mixture of polystyrene and talc in the extruder 2.
A mixture prepared by adding 0 parts of the same was fed, and 4.2 parts of isobutane (0.72 mol / resin 1
Kg) was pressed in, kneaded well and then cooled, and the temperature of the foamable melt was adjusted to 165 ° C. at the outlet of the extruder 2. This foamable melt was melted using the apparatus shown in FIG.
When the melt viscosity at 100 sec ^-1 is measured, it is 6.9 × 10.
It was ³ poise.

In the merging adapter 21 shown in FIG.
The ratio of the foamable melt introduced from the inlet to the inlet 31 is 45
The rate of the foamable melt introduced from the extruder 2 to the inlet 32 was 30 Kg / hour. Inlet 3
The resin introduced from 2 advances while being divided into the central cylindrical passage 321 and the outer peripheral cylindrical passage 322, while the resin introduced from the introduction port 31 is located between the passage 321 and the passage 322. After traveling through the cylindrical passage 311, these resins merge at the outlet 30 of the adapter 21 and A-A
The structure shown in the cross section was adopted so that the process could proceed.
After that, these resins enter the base 22 and the torpedo 2
It collides with 21 and becomes a cylindrical shape with three layers combined, and the base 2
110 mm inner diameter and 0.8 mm gap provided at the outlet of 2
Was extruded as a three-layer laminate from the orifice. The die 22 had an inlet hole temperature of 150 ° C. and an orifice portion temperature of 140 ° C.

The laminate extruded from the die 22 foamed immediately after leaving the die. The foamed laminate has an outer diameter of 332
traveling in a cylindrical shape along a cooling mandrel 25 made of aluminum of mm, and withdrawn at a withdrawing speed of 6.5 m / min,
A flat sheet was made by cutting open at the rear end of the mandrel.
In the obtained sheet, the three layers are orderly overlapped and firmly integrated, and each layer is uniformly foamed with a uniform thickness, and a non-uniform layer is formed at the joint of the layers. It was not recognized at all.

[0040]

Example 2 In this example, a device shown schematically in FIG. 3 was used, and the die having the structure shown in FIG.

The extruders 1 and 2 were both tandem extruders. The tandem extruder has a diameter of 50 m.
A first extruder having a diameter of 65 mm and a second extruder having a diameter of 65 mm are connected to each other, and a foaming agent pressure inlet is provided in the middle of the barrel of the first extruder.

In the extruder 1, recovered polystyrene was used as the resin, and 100 parts of the recovered polystyrene was mixed with 0.4 part of talc. As the foaming agent, a mixture consisting of 65 parts of normal butane and 35 parts of isobutane was used, and the mixture was pressed at a ratio of 2.3 parts to 100 parts of the resin (0.40 mol / 1 Kg of the resin), well kneaded, and then cooled. The resin was introduced into the inlet 33 of the die 23 at a resin temperature of 170 ° C. at a rate of 60 kg / hour. The above-mentioned recovered polystyrene was one used by a consumer, collected by a supermarket, washed and pelletized, and had a melt index of 3.8. This foamable melt was heated at 200 ° C. and r = 100 s by the apparatus shown in FIG.
When the melt viscosity was measured under the condition of ec ⁻¹ , the melt viscosity was 7.1 × 10 ³ poise.

In the extruder 2, 100 parts of polystyrene (denkastyrol HRM-2, manufactured by Denki Kagaku Co., Ltd., melt index 1.7) was mixed with 0.8 part of talc and 3.0 parts of a masterbatch containing a brown pigment. The resulting mixture was fed. As the foaming agent, the butane used in the extruder 1 was press-fitted at a ratio of 4.0 parts (0.68 mol / 1 Kg of resin) to 100 parts of the resin, kneaded well, cooled, and then divided into two parts each by a melt pump. The resin temperature 16 to the inlet 34 and the inlet 35 of the die 23 via the melt pump 12 and the melt pump 13.
It was introduced at a rate of 20.0 Kg / hour at 5 ° C. The melt pump was a 28/28 type gear pump manufactured by MAAG and rotated at 34.5 rpm. The foamable melt had a viscosity of 7.6 × 10 ³ poise as measured by the apparatus shown in FIG. 1 under the conditions of 200 ° C. and r = 100 sec ⁻¹ .

The die 23 of FIG. 4 was kept at 155 ° C. In the mouthpiece 23, the foamable melt introduced from the inlet 33 was made to collide with the torpedo 231 and was put into the cylindrical passage 232 to be formed into a cylindrical shape, which was then advanced to the outlet side. In addition, the foamable melt introduced through the inlet 34 is torpedo 231.
Was introduced into a cylindrical passage 234, molded into a cylindrical shape, and advanced to the outlet side. In addition, the foamable melt introduced from the inlet 35 was guided to the cylindrical passage 235 by the outer edge of the torpedo 231, molded into a cylindrical shape, and advanced to the outlet side. The melt thus advanced to the outlet side is merged in the passage 236 to form a three-layer laminate, which has an inner diameter of 120 m.
m and a gap of 0.6 mm.

The extruded laminate foamed immediately upon exiting the orifice. This foam was guided onto an aluminum cooling mandrel 25 having an outer diameter of 410 mm, advanced over this, and drawn at a speed of 6.5 m / min, and a cylinder was cut open at the rear end of the mandrel to form a flat sheet. The obtained sheet has three layers that are orderly overlapped and strongly integrated, and each layer has a uniform thickness and is uniformly foamed, and there is no uneven layer at the joint of each layer. I was not able to admit.

[0046]

[Embodiment 3] In this embodiment, a device schematically shown in FIG. 5 is used, and as the adapter 21 and the mouthpiece 23, those having the structures shown in FIG. 6 are used. made.

The extruders 1, 2 and 3 were all tandem extruders. In the tandem extruder, the extruder 1 is a combination of a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm, and the extruders 2 and 3 are both the first extruder having a diameter of 50 mm. The machine was connected to a second extruder having a diameter of 65 mm, and each had a foaming agent pressure inlet provided in the middle of the barrel of the first extruder.

In the extruder 1, a mixture of 90 parts of recovered polystyrene and 10 parts of thermoplastic elastomer was used as a resin, 100 parts of this mixture was mixed with 0.4 part of talc powder, and the mixture was supplied to the extruder 1. . As the foaming agent, a mixture consisting of 65 parts of normal butane and 35 parts of isobutane was used, and the mixture was pressed under a ratio of 2.8 parts to 100 parts of resin (0.48 mol / resin 1 Kg), well kneaded, and then cooled.
Resin temperature of 165 ° C. to the inlet 36 of the merging adapter 21
It was introduced at a rate of 90 Kg / hour. The above-mentioned recovered polystyrene was one that was once used as a tray made of expanded polystyrene, was recovered, was washed, and was made into pellets, and had a melt index of 3.8. As the thermoplastic elastomer, Tuffprene A manufactured by Asahi Kasei Corporation and having a melt index of 2.6 was used.
This foamable melt is produced by the device shown in FIG.
When the melt viscosity was measured under conditions of ° C and r = 100 sec ^-1 , the melt viscosity was 6.7 x 10 ³ poise.

In the extruder 2, 100 parts of polystyrene (made by Asahi Kasei Corp., polystyrene 683) and 0.8 parts of talc powder were used.
Parts and 3.0 parts of a brown pigment masterbatch were mixed to obtain a mixture. The blowing agent used was the same butane as used in Extruder 1 in a ratio of 3.8 parts to 100 parts of resin (0.6
(4 mol / resin 1 kg), kneaded well, cooled, and then introduced into the inlet 38 of the merge adapter 21 at a resin temperature of 170
It was introduced at a rate of 50 Kg / hour at 0 ° C. This foamable melt had r = 100 at 200 ° C. by the apparatus shown in FIG.
When the melt viscosity was measured under the condition of sec ^-1 , the viscosity was 6.8 × 10 ³ poise.

To the extruder 3, a mixture obtained by mixing 0.8 part of talc powder with 100 parts of the same polystyrene as the extruder 2 was supplied. As the foaming agent, the same butane as used in the extruder 1 was press-fitted at a ratio of 3.5 parts to 100 parts of resin (0.60 mol / 1 Kg of resin), mixed well, and cooled, and then the merging adapter 21 4 at the resin temperature of 170 ℃ to the inlet 37
It was introduced at a rate of 0 Kg / hour. This foamable melt is
By the device shown in FIG. 1, r = 100 sec at 200 ° C.
^{When the} melt viscosity is measured under the condition of ^-1 , the viscosity is 6.4.
It was × 10 ³ poise.

In the merging adapter 21 shown in FIG. 6, the adapter 21 is kept at 160 ° C., and the foamable melt introduced from the extruder 1 to the inlet 36 is collided with the torpedo 211 and put into the tubular passage 212 to form a cylinder. Extruder 2
The foamable melt introduced into the inlet 37 from the extruder 3 is put into the cylindrical passage 213 inside the torpedo 211 to form a cylindrical shape, and the foamable melt introduced from the extruder 3 to the inlet 38 is torpedo. A tubular passage 214 outside 211
It was put into the inside and formed into a cylindrical shape, and these melts were merged at the outlet 215 to form a cylinder having three layers.

Then, this cylinder is introduced into the base 22,
The mouthpiece 22 is maintained at 150 ° C., and a cylindrical melt composed of three layers is collided with the torpedo 221 in the mouthpiece 22 to be put into the cylindrical passage 222, and is formed into a cylindrical shape to form the orifice 22.
Extruded as a 3 to 3 layer laminate. Orifice 22
3 has an inner diameter of 205 mm and a gap of 0.6 mm
It was maintained at 0 ° C.

The laminate extruded from the die 22 foamed immediately after leaving the die. The foamed laminate has an outer diameter of 6
It proceeded in a cylindrical shape along a 65 mm aluminum cooling mandrel, was drawn off at a speed of 8.0 m / min and was cut open at the rear end of the mandrel into a flat sheet. The obtained sheet has three layers that are orderly overlapped and firmly integrated, and each layer has a uniform thickness and is uniformly foamed, and there are no non-uniform layers at the joints of each layer. I was not able to admit.

[0054]

COMPARATIVE EXAMPLE In this comparative example, the same device as in Example 3 was used. The resin used was almost the same, but the viscosity relationship of the expandable melt was changed. The details were performed as follows.

In FIG. 5, the above-mentioned caliber 65 mm and 90
In a tandem extruder 1 consisting of two extruders of 2 mm and 90 mm, 90 parts of the recovered polystyrene pellets (melt index 3.8) used in Example 3 and a thermoplastic elastomer (Tufpren A, manufactured by Asahi Kasei Corporation, melt index 2. 6)
A mixture of 10 parts and 0.4 part of talc powder was fed. After melting this mixture in the first extruder, 3.3 parts of the same butane as used in Example 3 from the barrel of the first extruder to 100 parts of resin (0.57 mol / Kg of resin).
At a rate of 90 Kg / hour, the foamable melt was introduced into the inlet 36 of the merging adapter 21 at a rate of 90 ° C./hour. When the melt viscosity of this foamable melt was measured at 200 ° C. under the condition of r = 100 sec ⁻¹ with the apparatus shown in FIG. 1, the melt viscosity was 6.4.
It was × 10 ³ poise.

In a tandem extruder 2 consisting of two extruders having a diameter of 50 mm and 65 mm, 100 parts of polystyrene (polystyrene 683 manufactured by Asahi Kasei Corporation) used in Example 3 was added, 0.8 parts of talc powder and a brown pigment were contained. A mixture obtained by mixing with 3.0 parts of the masterbatch was supplied. After melting this mixture in the first extruder, the same butane used in the extruder 1 was added to the resin 10 from the middle of the barrel of the first extruder.
Ratio of 3.0 parts to 0 parts (0.50 mol / resin 1K
The foamable melt obtained by press-fitting in (g), thoroughly kneading, and then cooling was introduced into the inlet port 38 of the merging adapter 21 at a temperature of 165 ° C. at a rate of 50 Kg / hour. This foamable melt was r = 10 at 200 ° C. by the apparatus shown in FIG.
When the melt viscosity was measured under the condition of ⁰ sec ⁻¹ , the melt viscosity was 7.4 × 10 ³ poise.

Further, the same polystyrene as that used in the extruder 2 (polystyrene 68 manufactured by Asahi Kasei Corp.) was used in the tandem extruder 3 composed of two extruders having the diameters of 50 mm and 65 mm.
3) To 100 parts, a mixture obtained by mixing 0.8 parts of talc powder was supplied. After melting the resin in the same manner as in the extruder 2, from the middle of the barrel of the first extruder, the same butane used in the extruder 2 was used in a ratio of 3.6 parts to 100 parts of the resin (0.62 mol / 0.6 Resin (1 Kg) was pressed in, kneaded well, and then cooled to obtain a foamable melt at a temperature of 165 ° C.
Inlet 37 of the merge adapter 21 at a rate of 0 Kg / hour
Introduced to. The foamable melt had a melt viscosity of 6.9 × 10 ³ poise as measured by the device shown in FIG. 1 at 200 ° C. under the condition of r = 100 sec ⁻¹ .

Therefore, the ratio of the melt viscosity of the melt from the extruder 2 to that of the melt from the extruder 1 is 1.
It became 16 and became larger than 1.1 times.

The merging adapter 21 shown in FIG. 6 was carried out in exactly the same manner as in Example 3 thereafter. That is, the temperature of the adapter is maintained at 160 ° C., and the inlet port 36 is fed from the extruder 1.
The foamable melt introduced into the torpedo 211 is collided into the tubular passage 212 to form a cylindrical shape, and the foamable melt introduced from the extruder 2 to the inlet 37 is circled inside the torpedo 211. The foamable melt introduced into the introduction port 38 from the extruder 3 by being put into the columnar passage 213 and formed into a columnar shape is provided in the tubular passage 214 outside the torpedo 211.
It was put into the inside and formed into a cylindrical shape, and these melts were merged at the outlet 215 to form a cylinder having three layers.

Then, this cylinder is introduced into the base 22,
While holding the die 22 at 150 ° C., a cylindrical melt having three layers was collided with the torpedo 221 to be put into the cylindrical passage 222, molded into a cylindrical shape, and extruded from the orifice 223 as a three-layer laminate. The inner diameter of the orifice 223 is 2
The distance was 05 mm and the gap was 0.6 mm, and the temperature was maintained at 140 ° C.

The laminate extruded from the die 22 foamed immediately after leaving the die. The foamed laminate has an outer diameter of 66.
It was cylindrically advanced along a 5 mm aluminum cooling mandrel, cooled, drawn off at a speed of 8.0 m / min and cut open at the rear end of the mandrel into a flat sheet. This sheet has a thickness of about 2.2 mm and a density of 0.0.
The foamed sheet laminate had a weight of 82 g / cm ³ , a width of 1040 mm, a brown surface, and a colorless back surface.

In this laminate, no particular turbulence was observed between the intermediate layer and the back layer, but turbulent flow was observed at the joint between the surface layer and the intermediate layer, and the surface was brown. Color unevenness was observed. This is because the ratio of the viscosity of the melt from extruder 2 to the viscosity of the melt from extruder 1 is 1.1.
It was 6 and was because it was larger than 1.1 times.

[Brief description of drawings]

FIG. 1 is a model view of an apparatus for measuring the viscosity of a foamable melt used in the method of the present invention.

FIG. 2 is a model view showing an embodiment of the method of the present invention together with a cross section of an apparatus used therein.

FIG. 3 is a diagram schematically showing another embodiment of the method of the present invention.

FIG. 4 is a model view of a mouthpiece that can be used in the embodiment shown in FIG.

FIG. 5 is a model view of still another embodiment of the method of the present invention.

FIG. 6 is a model view of a mouthpiece that can be used in the embodiment shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Extruder 2 Extruder 3 Extruder 22 Clasp 23 Clasp 21 Merging adapter in the clasp 25 Cooling mandrel 11 Melt pump 12 Melt pump 13 Melt pump

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Claims (2)

[Claims] 1. A laminated body of foamed sheets in which at least three layers of styrenic resin foamed sheets having different compositions are overlapped and integrated, and each layer is uniformly foamed inside the laminated body. A styrene-based resin foam sheet laminate, wherein each layer is evenly foamed and solidly integrated at the joints of the respective layers in the same manner as the remaining portions. 2. Thermoplastic resins having different compositions are melted in different extruders, respectively, are separately put into one die to form a sheet, and are joined in the same die, and at least three layers are formed. In the method for producing an integrated resin laminate, a styrene resin is selected as the resin, and an aliphatic hydrocarbon, an alicyclic hydrocarbon, or a halogenated aliphatic hydrocarbon having a boiling point lower than the softening point of the styrene resin is selected. , Pressing carbon dioxide or nitrogen into the molten resin in the extruder,
The resin is made foamable to form a foamable melt, and the viscosity of the foamable melt that comes to the outer shell of the laminate is made 1.1 times or less than the viscosity of the foamable melt that comes to the inner shell and merged. A method for producing a styrene-based resin foam sheet laminate, which comprises extruding the resin melt as a laminate integrally fused and extruding the resin melt outside the die.