JP2916341B2 - Styrene-based resin foam sheet laminate and method for producing the same - Google Patents

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]

2. Description of the Related Art Styrene resin foam sheets have been produced by extrusion foaming. The foam sheet made by extrusion foaming always had a high-density skin on its surface. This is because, when the expandable styrene resin is extruded from a die, the extruded resin is cooled by contacting the surface with air, so that the surface cannot be foamed at a high magnification like inside.

[0003] Laminating foam sheets is required, for example, to make foams whose surface is different in color from the interior. In such a case, a method has been adopted in which a foamed sheet has been separately formed by extrusion foaming and then bonded together later. As described above, when foamed sheets were separately formed and then bonded together, a different layer was always formed at the time of bonding, which caused inconvenience.

[0004] More specifically, to bond the foamed sheets, there are a typical method of fusing with heat and a method of bonding with an adhesive. Among these, in the method of fusing by heat, even if the skin is peeled off from the surface of the foamed sheet and fused, heating for fusion produces a high-density skin on the surface, and in the interior close to the skin, Since secondary foaming is caused and the air bubbles are coarsened, a remarkable heterogeneous layer is formed as a whole at the bonding seam. Also,
In the method of bonding with an adhesive, if an adhesive having a large dissolving power for a foam sheet is used, the adhesive dissolves the surface of the foam sheet to form a high-density layer on the surface, and as an adhesive, When a material having a low dissolving power to the foamed sheet was used, the adhesive newly formed a foreign layer. In addition, when bonding was performed while leaving a high-density skin on the surface, an uneven layer was more remarkably formed at the seam. Therefore, in any case, a remarkable heterogeneous layer was formed at the time of bonding.
For this reason, the conventional foamed sheet laminate not only has poor appearance, but also has a poor feel, and has a disadvantage in processing.

[0005] When a laminate is made from a non-foamed sheet, a co-extrusion method is employed. Co-extrusion is a method in which thermoplastic resins having different compositions kneaded by different extruders are separately put into one die, each resin is separately formed into a sheet shape, and the obtained sheet material is put into the same die. This is a method of joining together and bonding them together and extruding them as a laminate from one die. This method is theoretically considered to be applicable to a foamed sheet, but it has been difficult to actually apply the method to a foamed sheet.

The reason that the co-extrusion 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, when the sheet-like melts are merged in the die, the sheet-like melts easily enter and mix with each other, unlike the case where only the thermoplastic resin is used. For example, the foaming composition greatly changes the melt viscosity depending on the type and content of the foaming agent contained, and furthermore, the foaming rate greatly changes only by a slight change in the melt viscosity, and in an extreme case, the foaming or foaming is performed. It is because there is not. In addition, it has not been specifically studied how to coextrude the foamable composition.

[0007]

SUMMARY OF THE INVENTION The inventor of the present invention has sought to produce a laminate of a foamed sheet made of a styrene-based resin and having no foreign substance layer at the joint of each foamed sheet. In addition, the inventor has attempted to make such a laminate of foamed sheets by co-extrusion.

[0008]

Means for Solving the Problems When the foamable composition is joined in a die by a co-extrusion method to form a laminate according to the above-mentioned co-extrusion method, the foamable composition is not mixed and fixed. It has been found that the melt viscosity of the foamable composition is an important factor in merging as a layer to form a desired laminate.

In general, the melt viscosity of an expandable composition varies greatly depending on the additive added to the same resin, particularly on the type of the foaming agent contained in the resin, and also greatly depends on the content of the additive. is there. Further, the melt viscosity greatly varies depending on the temperature of the foamable composition and the temperature of the passage in the die. However, in co-extrusion, the particles pass through the same die, so that the temperature difference is small. Therefore, in co-extrusion, the melt viscosity can be adjusted mainly by only 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, particularly the foaming agent.

The inventor of the present invention uses a styrene-based resin as a resin when a melt of foamable resins having different compositions is merged in one die to form a laminate. If the foaming agent is blended with each resin composition so that the viscosity of the melt coming out of the resin is lower than the viscosity of the melt coming in, the seam of the foamed sheet is formed orderly by co-extrusion. It was found that the heterogeneous layer was not formed in the eyes. As a result of repeated tests, as long as a styrene-based resin is used as the resin, the viscosity of the outward melt does not need to be lower than the viscosity of the inward melt, specifically, the viscosity of the outward melt. It has been found that a foam laminate having no extraneous layer as described above can be obtained if is less than 1.1 times 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 is to melt thermoplastic resins having different compositions in different extruders, separately put them into one die, form them into a sheet, and merge them in the same die, at least. In a method of manufacturing 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,
A halogenated aliphatic hydrocarbon, carbon dioxide or nitrogen is injected into the molten resin in the above extruder to give the resin foaming property to form a foamable melt, and the viscosity of the resin melt coming to the outside of the laminate is adjusted to the internal value. It is characterized by being merged with the resin melt having a viscosity of 1.1 times or less and coming out from the die as a laminated body in which the resin melts are fused together and foaming outside the die. It is.

Further, the invention of a product is directed to a styrene-based resin foam sheet laminate obtained by the above method. The laminated body is characterized in that there is no heterogeneous layer such as a high-density layer at the joint of each layer, and all the layers inside are uniformly foamed and adhered. That is, the laminate is a laminate of a foamed sheet in which at least three layers of styrene-based resin foam sheets having different compositions are overlapped and integrated, and each layer is uniformly foamed inside the laminate. Also, at the joint of the above-mentioned layers, each layer is characterized by being uniformly foamed and firmly integrated like the other portions.

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, but a copolymer of styrene or a derivative thereof,
And a graft polymer. Here, the styrene derivative is, for example, α-methylstyrene, chlorostyrene and the like. The styrene or styrene derivative copolymer is, for example, a copolymer of styrene or α-methylstyrene with 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 can be used by mixing them,
It can also be used by mixing with another resin, for example, a compatible resin such as polyphenylene ether. Further, these styrene-based resins may be recovered products of defective products formed in a molding process such as extrusion molding and pressure molding, or may be recovered products of food containers used in the market.

In the present invention, styrene resins having different compositions are used. It is needless to say that the term “different composition” includes the case where the styrene resin itself is different.However, even when the styrene resin itself is the same, only the dye, pigment, and other additives are different. Also included. In other words, different compositions mean resin compositions that cannot be kneaded with the same single extruder.

In the present invention, an extruder is used. The extruder is
A rotatable screw is installed in a barrel that can be heated, and a mechanism that heats and melts the styrene resin and extrudes the styrene resin from a die attached to the end of the barrel. 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, a foaming agent is pressed into the styrene resin melted in the extruder. For that purpose, a pressure inlet for the foaming agent is provided in the middle of the barrel constituting the extruder,
From there, a foaming agent is injected. The resin melted by the injection of the foaming agent is provided with foaming properties. The foamed melt is then cooled to a temperature suitable for foaming. It is preferable to use an extruder 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 to obtain a foamable melt.
In the tandem extruder, the resin is melted in the first extruder, a foaming agent is pressed in, the foamable melt is cooled to a suitable foaming temperature in the second extruder, and then the foamable melt is extruded from a die. It is assumed that.

In the present invention, resins having different compositions are melted by different extruders to form foamable melts. For example, one tandem extruder is used to make a red foamable melt and another 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 a resin composition having a different composition is extruded, it is necessary to use a plurality of extruders, but only one die is used. For this purpose, foamable melts made in a plurality of series are all separately placed in the same die, and are initially separately sheeted. However, those formed into a sheet shape are then combined in the same die to form a laminate. Such ferrules have already been used to make non-foamed resin laminates. The base used in the present invention is basically the same as that used for laminating non-foamed resin.

To laminate a non-foamed resin, two
Kinds 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, which is joined together, and extruded as a flat 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 having a common axis, and the two are merged and extruded as a cylindrical laminated body. In the present invention, any of the two types of bases can be used. Among them, a method using a circular die is preferable.

When a circular die is used, it is preferable to use a merging adapter between the extruder and the die. The merging adapter receives foamable melts from multiple extruders through separate inlets, and initially forms each melt separately into a column or cylinder with a common axis, and then the outlet. A column or cylinder made of glue is merged to form an integrated laminate. The merging adapter decides to send this to the base after forming the laminate.

In the present invention, it is preferable that a melt pump, that is, a gear pump for transporting the melt at a constant rate, is provided between the extruder and the mouthpiece or the joining adapter. By using this pump, the foamable melt from the extruder can always be sent to a die or a merger at a constant rate.

The present invention is different from laminating non-foamed resins in that the styrenic resin contains a foaming agent and is made into a foamable melt. As the foaming agent, a volatile foaming agent is used. A volatile foaming agent is a gas or liquid with a boiling point lower than the softening point of the resin, which dissolves in the molten resin under pressure, but due to its low solubility, volatilizes from the molten resin under normal pressure. Is a gas or liquid with

The blowing 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 and 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 can be used alone or as a mixture. Preferred among these are aliphatic hydrocarbons, alicyclic hydrocarbons and halogenated aliphatic hydrocarbons.

The above-mentioned volatile foaming agent has a property of lowering the melt viscosity of a styrene resin.
That is, the greater the injection amount of the blowing agent, the lower the melt viscosity of the styrenic resin. In addition, the rate of the viscosity reduction is a value specific to each foaming agent. For example, aliphatic hydrocarbons greatly reduce the melt viscosity of a styrene-based resin even when they are injected into a small amount of a styrene-based resin, but nitrogen does not significantly reduce the melt viscosity when only a small amount is injected into a styrene-based resin. .

According to the present invention, a plurality of foamable melts having a specific relationship are defined as one based on the melt viscosity of a foamable melt produced by injecting a foaming agent into a melt of a styrene resin. The biggest feature is that they join in the base. To be more specific, the greatest feature is that the viscosity of the foamable melt coming to the outside of the laminate is 1.1 times or less the viscosity of the foamable melt coming to the inside of the laminate. .
The value of 1.1 times this is a value found by the present inventors by repeating lamination foaming experiments using a styrene-based resin.

In the present invention, the viscosity of the foamable melt is used as a reference, and the viscosity is generally referred to as apparent melt viscosity. The viscosity of the foamable melt as a reference in the present invention does not reverse depending on the composition, as long as the same temperature and pressure are used even if the temperature and pressure slightly change. 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 foaming extruder into which a foaming agent can be press-fitted. The base 100 is filled with a melt of expandable styrene resin from the inlet 101 and has a diameter of 5 mm.
Is pushed out from the outlet 103 through the passage 102. At this time, the extrusion rate Q is such that the shear rate r in the passage 102 is 100 sec ⁻¹ (the extrusion rate Q = 4420 cm).
³ / hr, density at 1.0 g / cm ³ 4.42 kg /
hr), 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 / sec)
c), pressure loss ΔP (L in the middle of a 0.5 cm diameter circular pipe)
= 5 cm differential pressure between the pressure gauge and the pressure gauge mounted at a distance of Gr / cm ² ). The data obtained is used to obtain the shear rate and apparent melt viscosity using the equation for Newtonian fluid 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 foamable melt may contain various 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 regulator, an antistatic agent, an antioxidant, and a stabilizer. However, strictly speaking, the above-mentioned melt viscosity should be a value obtained by adding these additives.However, additives other than the foaming agent do not have the added amount as large as the foaming agent, Also, since the ability to change the melt viscosity of the resin is small, this can be approximately ignored.

Based on the apparent viscosity value thus obtained, the melt viscosity of the resin composition exposed to the outside of the laminate is 1.1 times or less the melt viscosity of the resin composition exposed to the inside of the laminate. The greatest feature of the present invention is that the relationship between the styrene resin and the foaming agent is adjusted so as to be used.

Among them, it is preferable that the melt viscosity of the resin composition exposed to the outside of the laminate is 1.1 to 0.5 times the melt viscosity of the resin composition exposed to the inside, more preferably 1 to 0.5. 0.0 to 0.7 times.

[0032]

According to the method of the present invention, a styrene resin is selected as a 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 used as a foaming agent. Since this blowing agent is press-fitted into a styrene-based resin melted in an extruder using a selected one of hydrocarbon, carbon dioxide and nitrogen, a foamable melt can be easily produced. The foamable melt thus obtained can easily have a desired melt viscosity by adjusting the type and amount of the foaming agent to be press-fitted. Then, compositions of styrene-based resins having different compositions are melted in separate extruders, put into one die and formed into a sheet shape, and at least three layers are merged and laminated in the same die. In forming a sheet, the viscosity of the foamable melt coming to the outside of the laminate is joined to be 1.1 times or less the viscosity of the foamable melt coming to the inside, so that the foamable composition is It becomes a precise layer and adheres without mixing. For this reason, the laminate is extruded from the die and foamed outside the die to obtain a uniformly foamed laminate having no foreign matter layer. The advantage of the present invention is great in that a laminate made of a foamed sheet of a styrene-based resin can be easily obtained at once.

Further, the laminate of the styrene-based resin foam sheets obtained in this way is formed by laminating at least three layers of styrene-based resin foam sheets having different compositions, and furthermore, each layer is uniformly formed inside the laminate. Also at the joint of the above-mentioned layers, it is foamed at a uniform density similarly to the rest of each layer. That is,
Unlike the conventional laminate, a high-density layer is not formed at the joint of each layer, and there is no foreign substance layer at the joint of each layer. Therefore, the laminate according to the present invention has a good appearance and feel, and is easy to process because there is no foreign substance layer. On top of that, the obtained laminate is usually 0.3-0.0
It has a density of 4 g / cm ³ and is therefore generally suitable for use as a foam. Also, since it is composed of at least three layers, it is possible to use a recycled styrene resin which has been used 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 regenerated product, a laminate similar to that using a new material can be obtained. In these respects, the laminate according to the present invention has a large utility value.

[0034]

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, an intermediate layer of an expandable melt extruded from an extruder 1 was formed using an apparatus schematically shown in FIG. The articles were located on both sides of the intermediate layer, resulting in a three-layer foam sheet laminate.

As the extruder 1, a tandem type foam extruder was used, 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 thereto. A mixture obtained by adding 0.6 part of talc powder to 100 parts of a polystyrene resin (manufactured by Asahi Kasei Corporation, polystyrene 683, melt index: 2.8) is supplied to the extruder 1, which is melted and then foamed from the middle of the first extruder. Isobutane as an agent
Five parts (0.43 mol / kg of resin) were press-fitted and kneaded well, and cooled in the second extruder so that the temperature of the foamable melt was 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. In the extruder 2, a masterbatch containing a mixture of polystyrene and talc and further containing a pink pigment.
0 parts was added, and 4.2 parts of isobutane (0.72 mol / resin 1) was used as a blowing agent in the middle of the extruder.
Kg) was press-fitted, kneaded well and then cooled, and the temperature of the foamable melt was set to 165 ° C. at the outlet of the extruder 2. This foamable melt was heated at 200 ° C. using the apparatus shown in FIG.
The melt viscosity at 100 sec ^-1 was measured to be 6.9 × 10
³ poise.

In the merging adapter 21 shown in FIG.
The ratio of the foamable melt introduced into the inlet 31 from
Kg / hour, and the rate of the foamable melt introduced from the extruder 2 into the inlet 32 was 30 kg / hour. Inlet 3
The resin introduced from 2 advances into a cylindrical passage 321 at the center and a cylindrical passage 322 on the outer periphery, and the resin introduced from the inlet 31 is located between the passage 321 and the passage 322. After proceeding through the cylindrical passage 311, these resins are combined at the outlet 30 of the adapter 21 and A-A
The structure proceeds as shown in the cross section.
After that, these resins enter into the base 22, and the torpedo 2
21 collides with three layers to form a cylindrical shape.
110mm inner diameter and 0.8mm gap provided at the outlet of No.2
Extruded as a three-layer laminate. The temperature of the inlet 22 of the base 22 was 150 ° C., and the temperature of the orifice portion was 140 ° C.

The laminate extruded from the die 22 foamed immediately after leaving the die. The outer diameter of the foamed laminate is 332
mm along a cylindrical cooling mandrel 25 made of aluminum and is taken off at a take-off speed of 6.5 m / min.
A flat sheet was cut out at the rear end of the mandrel.
In the obtained sheet, three layers are orderly overlapped and firmly integrated, each layer is uniformly foamed with a uniform thickness, and an uneven layer is formed at the joint of the layers. Not at all.

[0040]

EXAMPLE 2 In this example, a laminate of foamed sheets was produced by using the apparatus schematically shown in FIG. 3 and using the die having the structure shown in FIG.

As the extruders 1 and 2, tandem extruders were used. Each of the tandem extruders has a diameter of 50 m.
m, and a second extruder having a diameter of 65 mm connected to the first extruder. 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 a resin, and a mixture of 100 parts of recovered polystyrene and 0.4 part of talc was supplied. As a foaming agent, a mixture consisting of 65 parts of normal butane and 35 parts of isobutane was used. The mixture was press-fitted at a ratio of 2.3 parts (0.40 mol / 1 Kg of resin) to 100 parts of the resin, kneaded well, and then cooled. The resin was introduced into the inlet 33 of the base 23 at a resin temperature of 170 ° C. at a rate of 60 kg / hour. The above-mentioned recovered polystyrene was collected by a supermarket, used by a consumer, washed and made into pellets, and had a melt index of 3.8. This foamable melt was heated at 200 ° C., 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 an extruder 2, 0.8 part of talc and 3.0 parts of a brown pigment-containing master batch were mixed with 100 parts of polystyrene (Denka Styrol HRM-2, melt index 1.7, manufactured by Denki Kagaku). The resulting mixture was fed. As the blowing agent, butane used in the extruder 1 was press-fitted at a ratio of 4.0 parts (0.68 mol / Kg of resin) to 100 parts of the resin, kneaded well, cooled, divided into two parts and melt pumped. 12 and the melt pump 13, the resin temperature 16 is applied to the inlet 34 and the inlet 35 of the base 23.
It was introduced at a rate of 20.0 kg / hour at 5 ° C. The melt pump was a 28/28 gear pump manufactured by MAAG and rotated at 34.5 rpm. The viscosity of this foamable melt was measured at 200 ° C. and r = 100 sec ^{−1 using} the apparatus shown in FIG. 1, and the viscosity was 7.6 × 10 ³ poise.

The ferrule 23 of FIG. 4 was kept at 155 ° C. In the die 23, the foamable melt introduced from the inlet 33 was caused to collide with the torpedo 231, entered into the cylindrical passage 232, formed into a cylindrical shape, and advanced to the outlet side. Further, the foamable melt introduced from the introduction port 34 is supplied with torpedo 231.
, And was put into a cylindrical passage 234 to be formed into a cylindrical shape and then advanced to the outlet side. In addition, the foamable melt introduced from the inlet 35 was guided to the cylindrical passage 235 by the outside of the torpedo 231, formed into a cylindrical shape, and advanced to the outlet side. The melt that has proceeded to the outlet side in this way is merged in the passage 236 to form a three-layer laminate, which has an inner diameter of 120 m.
extruded from an orifice with a gap of 0.6 mm.

The extruded laminate foamed immediately upon exiting the orifice. The foam was guided on an aluminum cooling mandrel 25 having an outer diameter of 410 mm, and advanced over the aluminum cooling mandrel 25. The foam was taken out 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 resulting sheet is composed of three layers which are superimposed orderly and are firmly integrated, each layer is uniformly foamed with a uniform thickness, and there is no uneven layer at the joint of each layer. I was not able to admit.

[0046]

Embodiment 3 In this embodiment, the apparatus shown schematically in FIG. 5 is used, and the adapter 21 and the base 23 having the structure shown in FIG. 6 are used. made.

As the extruders 1, 2, and 3, tandem extruders were used. In the tandem extruder, the extruder 1 is configured by connecting a first extruder having a diameter of 65 mm and a second extruder having a diameter of 90 mm, and both of the extruders 2 and 3 have a first extruder having a diameter of 50 mm. The extruder was connected to a second extruder having a diameter of 65 mm, and each of them was provided with a blowing agent pressure inlet 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 a thermoplastic elastomer was used as a resin, and 0.4 part of talc powder was mixed with 100 parts of the mixture and supplied to the extruder 1. . As a foaming agent, a mixture of 65 parts of normal butane and 35 parts of isobutane was used, and the mixture was press-fitted at a ratio of 2.8 parts (0.48 mol / 1 kg of resin) to 100 parts of the resin, kneaded well, and then cooled.
A resin temperature of 165 ° C.
It was introduced at a rate of 90 kg / hour. In addition, the above-mentioned recovered polystyrene was obtained by recovering a tray once used as a foamed polystyrene tray and washing it to form pellets, and had a melt index of 3.8. The thermoplastic elastomer used was TUFPRENE A manufactured by Asahi Kasei Corporation with a melt index of 2.6.
This foamable melt is obtained by the apparatus shown in FIG.
The melt viscosity was 6.7 × 10 ³ poise when the melt viscosity was measured under the conditions of ° C. and r = 100 sec ⁻¹ .

In the extruder 2, 100 parts of polystyrene (manufactured by Asahi Kasei Corporation, polystyrene 683) was added to 0.8 parts of talc powder.
And 3.0 parts of a brown pigment masterbatch were mixed and supplied. As the blowing agent, the same butane used in the extruder 1 was used in a ratio of 3.8 parts (0.6 parts) to 100 parts of the resin.
4 mol / kg of resin), kneaded well, and then cooled.
Introduced at a rate of 50 kg / hour at 50 ° C. This foamable melt was subjected to r = 100 at 200 ° C. using the apparatus shown in FIG.
When the melt viscosity was measured under the conditions of sec ^-1 , the viscosity was 6.8 × 10 ³ poise.

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

In the merger adapter 21 shown in FIG. 6, the adapter 21 is maintained at 160 ° C., and the foamable melt introduced from the extruder 1 into the inlet 36 is caused to collide with the torpedo 211 to be introduced into the tubular passage 212 and to be introduced into the cylindrical passage 212. Extruder 2
From the extruder 3 into the inlet 38 through the extruder 3, into the torsion 211. Outside of 211 a tubular passage 214
The melts were combined at an outlet 215 to form a three-layer cylinder.

Thereafter, this cylinder is introduced into the base 22,
The base 22 is maintained at 150 ° C., and a three-layered cylindrical melt is collided with the torpedo 221 in the base 22 to enter the cylindrical passage 222, formed into a cylindrical shape, and formed into the orifice 22.
Extruded as a three to three layer laminate. Orifice 22
3 has an inner diameter of 205 mm, a gap of 0.6 mm and 14
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 traveled cylindrically along a 65 mm aluminum cooling mandrel, was drawn at a speed of 8.0 m / min, and was cut open at the rear end of the mandrel into a flat sheet. The resulting sheet is composed of three layers that are superimposed orderly and are firmly integrated, each layer is uniformly foamed with a uniform thickness, and there is no uneven layer at the joint of each layer. I was not able to admit.

[0054]

Comparative Example In this comparative example, the same apparatus as in Example 3 was used. Although the same resin was used as the resin, the relationship of the viscosity of the foamable melt was changed. Details were implemented as follows.

Referring to FIG.
In a tandem extruder 1 comprising two extruders, 90 parts of the recovered polystyrene pellets (melt index 3.8) used in Example 3 and a thermoplastic elastomer (Taphrene A, manufactured by Asahi Kasei Corporation, melt index 2. 6)
A mixture consisting of 10 parts and 0.4 part of talc powder was fed. After melting this mixture in the first extruder, 3.3 parts (0.57 mol / kg of resin) of the same butane as used in Example 3 were used from the barrel of the first extruder per 100 parts of resin.
The mixture was kneaded well, cooled and introduced into the inlet 36 of the merging adapter 21 at 160 ° C. at a rate of 90 kg / hour. The melt viscosity of this foamable melt was measured at 200 ° C. under the condition of r = 100 sec ^{−1 using} the apparatus shown in FIG.
× was 10 ³ poise.

In a tandem extruder 2 having two extruders having a diameter of 50 mm and 65 mm, 100 parts of polystyrene (manufactured by Asahi Kasei Corporation, polystyrene 683) used in Example 3, 0.8 parts of talc powder and a brown pigment A mixture obtained by mixing 3.0 parts of the master batch was supplied. After the mixture is melted in the first extruder, the same butane used in the extruder 1 is applied to the resin 10 from the middle of the barrel of the first extruder.
3.0 parts relative to 0 parts (0.50 mol / resin 1K
g), the mixture was kneaded well, and then cooled. The resulting foamable melt was introduced into the inlet 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.

A tandem extruder 3 composed of two extruders having a diameter of 50 mm and 65 mm was provided with the same polystyrene (polystyrene 68 manufactured by Asahi Kasei Corporation) used in the extruder 2.
3) A mixture obtained by mixing 0.8 parts of talc powder with 100 parts was supplied. After the resin is melted in the same manner as in the extruder 2, the same butane used in the extruder 2 is used in the barrel of the first extruder at a ratio of 3.6 parts (0.62 mol / (1 kg of resin), kneaded well, and then cooled.
Inlet 37 of merging adapter 21 at a rate of 0 kg / hour
Introduced. When the melt viscosity of this foamable melt was measured at 200 ° C. under the condition of r = 100 sec ⁻¹ , the melt viscosity was 6.9 × 10 ³ poises.

Accordingly, the ratio of the melt viscosity from the extruder 2 to the viscosity of the melt from the extruder 1 is 1.
16, which is larger than 1.1 times.

With the merger adapter 21 shown in FIG. That is, the temperature of the adapter was maintained at 160 ° C.
The foamable melt introduced into the torpedo 211 is made to collide with the torpedo 211 and is formed into a cylindrical shape by being introduced into the tubular passage 212, and the foamable melt introduced from the extruder 2 into the inlet 37 is circled inside the torpedo 211. The foamable melt introduced from the extruder 3 into the inlet 38 is introduced into the cylindrical passage 213 outside the torpedo 211.
Then, the melts were combined at an outlet 215 to form a three-layer cylinder.

Thereafter, the cylinder is introduced into the base 22,
The ferrule 22 was kept at 150 ° C., and a three-layered cylindrical melt was caused to collide with the torpedo 221 to be put into a cylindrical passage 222, formed into a cylindrical shape, and extruded from the orifice 223 as a three-layer laminate. The orifice 223 has an inner diameter of 2
05 mm, the gap was 0.6 mm and 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 cooled in a cylindrical fashion along a 5 mm aluminum cooling mandrel, pulled at a speed of 8.0 m / min, 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 was 82 g / cm ³ , width 1040 mm, the surface was brown, and the back was colorless.

In this laminate, no particular disorder was observed between the intermediate layer and the back layer, but a disordered 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 the extruder 2 to the viscosity of the melt from the extruder 1 is 1.1.
6, which was more than 1.1 times.

[Brief description of the drawings]

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

FIG. 2 is a model diagram 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 schematic diagram of a base that can be used in the embodiment shown in FIG. 3;

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

FIG. 6 is a schematic diagram of a base that can be used in the embodiment shown in FIG. 5;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 extruder 2 extruder 3 extruder 22 base 23 base 21 merge adapter in base 25 cooling mandrel 11 melt pump 12 melt pump 13 melt pump

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 9:00

Claims (2)

(57) [Claims] 1. A laminated body of a foamed sheet in which at least three layers of styrene-based resin foamed sheets having different compositions are overlapped and integrated, and each layer is uniformly foamed inside the laminated body. A styrenic resin foam sheet laminate characterized in that, at the joint of the above-mentioned layers, each layer is foamed uniformly and strongly integrated similarly to the other portions. 2. A thermoplastic resin having a different composition is melted in a separate extruder, and the melted resin is separately put into one die to form a sheet and merged in the same die. In a method of manufacturing an integrated resin laminate, a styrene-based resin is selected as a resin, and an aliphatic hydrocarbon, an alicyclic hydrocarbon, and a halogenated aliphatic hydrocarbon having a boiling point lower than the softening point of the styrene-based resin. Pressing carbon dioxide or nitrogen into the molten resin in the extruder,
The resin is foamed to form a foamable melt, and the viscosity of the foamable melt coming to the outside of the laminate is reduced to 1.1 times or less of the viscosity of the foamable melt coming to the inside of the laminate. A method for producing a styrene-based resin foam sheet laminate, characterized in that the resin melts are extruded as a laminate fused together from the die and foamed outside the die.