JPH11320799A - Laminated polycarbonate resin foamed sheet, its manufacture and box - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated polycarbonate resin foamed sheet which is lightweight, and has improved bending strength, good surface appearance and smooth surface, and a manufacturing method thereof. SOLUTION: A laminated polycarbonate resin foamed sheet is formed by laminating polycarbonate resin films or sheets A, A' and A", and polycarbonate resin foamed bodies B and B' in an order of A, B, B', and A', or A, B, A", B' and A'. Melting tensions of the polycarbonate resins forming the A and A' layers at 250 deg.C are 2.0 g or higher, each thickness of the A and A' layers is 10-750 μm, a thickness of the A" layer is 10-1500 μm, each density of B and B' layers is 0.06-0.6 g/cm<3> and each thickness thereof is 0.5-15 mm, each center line average roughness of the surface of the A and A' layers is 3.0 μm or lower, and a bending strength Y (kg/cm<2> ) of the foamed sheet satisfies an expression Y>266X<2> +147X, wherein X is an apparent density (g/cm<3> ) of the foamed sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminated polycarbonate resin foam board, a method for producing the same, and a box using the foam board as a base material.

[0002]

2. Description of the Related Art A laminated polycarbonate resin foam sheet formed by coextrusion or extrusion lamination using a polycarbonate resin foam sheet as a base layer and a polycarbonate resin film as a surface layer is disclosed in JP-A-8-174780.
No. 1993. In these co-extrusion methods or extrusion lamination methods, the viscosity average molecular weight of the polycarbonate resin used for the surface resin film is 2
When the molecular weight is 20,000 or more, it is described that the fluidity is poor for coextrusion or extrusion lamination and the thickness of the laminate tends to be nonuniform, and as examples, the viscosity average molecular weight is 18,000, 15,000 and 10,000. (Examples 1, 7 and 9). However,
Even if the foamed sheet obtained by the above method is used as a plate material, its mechanical strength such as bending strength is not always sufficient, and in general, a foamed sheet wound in a roll shape is simply heated to take up a roll. However, even if the sheet is processed into a plate shape, the appearance and smoothness of the foamed sheet are poor, for example, the foamed sheet is wavy. Further, for the purpose of increasing the strength of the foam, Japanese Patent Application Laid-Open No. 9-104093 proposes laminating the foams, but in this case, the obtained foam does not necessarily have sufficient strength and surface appearance. , And did not exhibit surface smoothness.

[0003]

SUMMARY OF THE INVENTION The present invention relates to a laminated polycarbonate resin foam plate which is lightweight, has improved bending strength, has a good surface appearance and a smooth surface, and a method for producing the same.
Another object is to provide a box using the foam board as a base material.

[0004]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, (i) a polycarbonate resin film or sheet (hereinafter, the film or sheet is simply referred to as a film) (A), a polycarbonate resin foam (B), a polycarbonate resin foam ( B ′) and each layer of the polycarbonate resin film (A ′) are laminated in this order, or (i.
i) Polycarbonate resin film (A), polycarbonate resin foam (B), polycarbonate resin film (A ″), polycarbonate resin foam (B ′), and polycarbonate resin film (A ′)
Is a laminated polycarbonate resin foam plate having a structure in which the respective layers are laminated in this order, wherein the polycarbonate resin forming the polycarbonate resin films (A) and (A ′) has a melt tension at 250 ° C. of 2 0.0 g or more, and the thickness of each of the polycarbonate resin films (A) and (A ′) is 10 to 750 μm.
m, the thickness of the polycarbonate resin film (A ″) layer is 10 to 1500 μm, and the density of each of the polycarbonate resin foams (B) and (B ′) is 0.0
6-0.6 g / cm ³ and the thickness is 0.5-
15 mm, the center line average roughness of the surface of the polycarbonate resin films (A) and (A ') on the surface layer of the foamed board is 3.0 μm or less, and the bending strength Y (kg /
cm ² ) which satisfies the following formula: Y> 266X ² + 147X (where X represents the apparent density (g / cm ³ ) of the foamed board) Further, according to the present invention, the resin for the foam comprising the foaming agent-containing polycarbonate resin and the melt tension at 250 ° C. And a resin for film consisting of a polycarbonate resin of 2.0 g or more is co-extruded with an annular die so that the latter is laminated on the outer peripheral surface or the outer peripheral surface and the inner peripheral surface of the former, and the film laminated tubular foam is formed. A method for producing a laminated polycarbonate resin foam board, comprising: a step of forming a body; and a step of fusing the inner surfaces of the foam to each other to form a foam board. Further, according to the present invention, there is provided a box based on the laminated polycarbonate resin foam board.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The laminated polycarbonate resin foam plate of the present invention is obtained by bonding and laminating each layer by using a coextrusion method or an extrusion lamination method. The co-extrusion method refers to a melt-kneaded product of a polycarbonate-based resin that is a raw material of a polycarbonate-based resin foam to be a foam layer and a polycarbonate-based resin that is a raw material of a polycarbonate-based resin film to be a film layer. Is co-extruded from a die using an extruder and foam-laminated to obtain a film-laminated foam plate composed of a film layer and a foam layer. In the extrusion lamination method, a polycarbonate-based resin foam plate is prepared in advance, and on the surface of the foamed plate, a melt-kneaded product of a polycarbonate-based resin that is a raw material of a polycarbonate-based resin film to be a film layer is extruded from an extruder. This is a method of obtaining a film-laminated foam plate composed of a film layer and a foam layer by laminating (lamination). In the present invention, of the above methods, the co-extrusion method is more preferably used. The method for obtaining a film laminated foam plate by this co-extrusion method will be described in more detail. A method of co-extrusion into a plate shape using a flat die to form a film laminated foam plate, and a method of co-extrusion using an annular die and forming a cylindrical shape A method of forming a laminated foam, then cutting it into a film laminated foam plate, co-extrusion using an annular die to form a tubular laminated foam, and the inner surface of the foam is in a bondable state Among them, there is a method in which the foam is sandwiched by a sandwiching roll and the inner surface is pressure-bonded and bonded to form a laminated film laminated foam plate (hereinafter, this method is also simply referred to as a co-extrusion pressure bonding method). According to the co-extrusion pressure bonding method, the above-described four-layer or five-layer laminated polycarbonate resin foam plate of the present invention can be obtained at once and continuously, and the productivity is extremely good. Further, as another method for obtaining the laminated polycarbonate resin foam board of the present invention, there is also a method in which a foam board prepared in advance and a film are bonded by an adhesive means such as heat or an adhesive.

In the present invention, the polycarbonate resin used as a starting material is a polyester formed from carbonic acid and glycol or bisphenol.
Aromatic polycarbonates having diphenylalkane in the molecular chain are preferred because they have excellent heat resistance, weather resistance and acid resistance. Such polycarbonates include 2,2-bis (4-oxyphenyl) propane (also known as bisphenol A), 2,2-bis (4-oxyphenyl) butane, and 1,1-bis (oxyphenyl)
Cyclohexane, 1,1-bis (4-oxyphenyl)
Examples include polycarbonates derived from bisphenols such as isobutane and 1,1-bis (4-oxyphenyl) ethane.

In the present invention, the polycarbonate resin forming the resin film (A) and the (A ′) layer (film layer) laminated on the surface of the laminated polycarbonate resin foam board has a melt tension of 250 ° C. At least 2.0 g, preferably at least 2.3 g. In the production of a film-laminated polycarbonate resin foam sheet by a coextrusion method or an extrusion lamination method, the viscosity average molecular weight of the polycarbonate resin used for the surface resin film is 2 as described in JP-A-8-174780.
If the molecular weight is less than 20,000, the molecular weight is 20,000 or more, the fluidity is poor for co-extrusion or extrusion lamination, the thickness of the obtained laminate is considered to be likely to be uneven, and those having a viscosity average molecular weight lower than 20,000 are used. Have been. The polycarbonate resin having a viscosity average molecular weight of less than 20,000, which is considered to be preferable, usually has a melt tension at 250 ° C. of less than 2.0 g. In the present invention, the melt tension is 2.0 g (250 g).
C)) or more as a surface layer, that is, when used as a resin for a film layer, surprisingly, it is possible to obtain a polycarbonate-based resin foam plate having a good surface appearance and improved bending strength, and having a smooth surface. By providing a surface layer by a co-extrusion method, the expansion ratio of a foam as a base layer can be sufficiently increased. The melt tension is 2.
A polycarbonate resin having a viscosity of 0 g (250 ° C.) or more usually has a viscosity average molecular weight of more than 20,000. When the melt tension is less than 2.0 g (250 ° C.), the melt tension of the resin is low. Therefore, when the foam serving as the base layer and the resin film serving as the surface layer are fused, the unevenness of the cells on the foam surface may be reduced. It also appears on the surface, and the surface of the obtained laminated foam becomes rough, and the bending strength of the foamed board is significantly reduced. Further, at the time of co-extrusion, or at the time of secondary heating performed for removal of warpage, waving, and the like of the obtained laminated foam, the surface of the foam is easily burnt, and the appearance and smoothness of the surface are reduced. Good or improved bending strength cannot be obtained. Although the upper limit of the melt tension is not particularly limited, it is usually 30.
g. Further, the melt tension (250 ° C.) of the resin of the resin film (A ″) layer provided as needed may not be 2.0 g or more, but it is intended to improve productivity and further improve physical properties of the laminated foam board. It is preferable to use the same resin as the resin film (A) and the layer (A ′).

[0008] In this specification, the melt tension is measured as follows. As a measuring device, using a melt tension tester type II manufactured by Toyo Seiki Seisaku-sho, Ltd., a polycarbonate resin adjusted by drying at 120 ° C. for 3 hours from a nozzle having an orifice diameter of 2.095 mm and an orifice length of 8 mm was used.
The resin is extruded into a string at 0 ° C. and a resin extrusion piston speed of 10 mm / min, and the string is hung on a tension detection pulley having a diameter of 45 mm, and further wound up by a winding roller located downstream. The winding speed of the winding roller is 100 r using a winding roller having a diameter of 50 mm.
pm. Then, the tension of the cord-like object detected by a detector connected to the pulley for tension detection at that time is measured and defined as a melt tension. In the above, the winding speed is set to 100
At the time of rpm, the winding speed is gradually increased (approximately 5 rpm / sec) and adjusted so as not to cut the string.
When the string is cut at a winding speed of 100 rpm and the string is cut, the tension detected at the winding speed at the time of cutting is defined as the melting tension.

In the present invention, the polycarbonate resin for a film layer is obtained at a temperature of 250 ° C. and a shear rate of 100 seconds.
The melt viscosity at ^-1 is preferably 5 × 10 ³ to 2 × 10 ⁵ poise, and more preferably 1 × 10 ^{4 to} 1.7 × 10 ⁵ poise. If the melt viscosity is too low, a resin having high fluidity will be present at the interface between the polycarbonate resin for the foam layer and the extruder cylinder wall or shaft wall, and the extrusion pressure will be reduced, making it difficult to achieve good foaming.
Also, even if the melt viscosity is too high, the temperature of the resin for the film layer becomes high since the resin for the film layer does not contain a foaming agent and has a much higher viscosity than the resin for the foam, so that
Even with a resin having a melt tension of 2 g or more at ℃, it is difficult to prevent burns on the surface of the laminated foamed board. In addition, in this specification, the melt viscosity is measured as follows. As a measuring device, a Chiast Corporation Leovis 2100 is used, orifice diameter 1 mm, orifice length 10 mm, measuring temperature 250 ° C., shearing speed 100 sec.
Measure under the condition of ^-1 . Further, the polycarbonate resin for a film layer has a viscosity average molecular weight of 20,000.
It is preferably at least 2, more preferably at least 22,000. If the viscosity average molecular weight is too low, a sufficient melt viscosity may not be obtained. On the other hand, if the viscosity average molecular weight is too high, the melt viscosity tends to increase, so the upper limit of the viscosity average molecular weight is usually 50,000.

Further, in the present invention, the viscosity average molecular weight of the polycarbonate resin for a foam layer is preferably 25,000 or more, more preferably 28,000 or more,
Further, the melt tension at 250 ° C. is preferably 2.3 g or more, more preferably 5.0 g or more. If the viscosity average molecular weight is too low, it leads to a decrease in the extruder die pressure during extrusion foaming, and it is difficult to obtain a good foam. Although the upper limit is not particularly limited, it is usually 5,000.
0. If the melt tension at 250 ° C. is too low, bubbles are easily broken during extrusion foaming, and it is difficult to obtain a good foam. The upper limit is not particularly limited.
g. Further, the polycarbonate resin for the foam layer preferably has a melt viscosity of 5 × 10 ⁴ to 2 × 10 ⁵ poise at a temperature of 250 ° C. and a shear rate of 100 sec ⁻¹ , and 6 × 10 ^{4 to} 1.8. More preferably, it is × 10 ⁵ poise. If the melt viscosity is too low, it is difficult to maintain the extrusion pressure required for foaming. If the melt viscosity is too high, heat is generated in the extruder, and it is difficult to control the temperature to an appropriate foaming temperature.

As the foaming agent, any of an inorganic foaming agent, a volatile foaming agent, and a decomposition type foaming agent can be used. As the inorganic foaming agent, carbon dioxide, nitrogen and the like are used. Examples of the volatile blowing agent include lower aliphatic hydrocarbons such as propane, n-butane, i-butane, n-pentane, i-pentane, and n-hexane; lower alicyclic hydrocarbons such as cyclobutane, cyclopentane, and cyclohexane. Are used.
The above-mentioned foaming agents can be used alone or in combination of two or more. For example, different types of foaming agents such as an inorganic foaming agent and a volatile foaming agent can be used in combination. In addition, a decomposition type foaming agent can be used in combination for adjusting the bubble diameter. The amount of the foaming agent used varies depending on the type of the foaming agent and the desired expansion ratio, and since the density of the foam is determined by the expansion ratio, it can be said that the amount of the foaming agent mainly depends on the desired density of the foam. The amount of the foaming agent used is generally 0.05 to 2 mol per 1 kg of the polycarbonate resin.

Hereinafter, a method for producing a sheet-like laminated foam mainly by the co-extrusion pressure bonding method will be described in detail. In this case, the polycarbonate resin films (A) and (A ′) and the polycarbonate resin foams (B) and (B ′) have the same composition. Furthermore, polycarbonate resin film (A '')
It is preferable that the composition of the layer is the same as that of the layers (A) and (A '). In the extruder, on the one hand, the foaming agent-containing polycarbonate-based resin is melt-kneaded to form a foamable resin melt-kneaded product, and on the other hand, the polycarbonate resin for the film layer is separately melt-kneaded to form a resin melt-kneaded product. Merge in an annular die provided at the tip of the extruder, laminate the latter on the outer peripheral surface or the outer peripheral surface and the inner peripheral surface of the former, and then co-extrude through the die under a lower pressure than in the extruder to foam and laminate. Forming a tubular laminated foam formed by laminating a foam and a resin film, forming a balloon while cooling the foam extruded into the tubular shape with air, and the inside of the balloon is in a bondable state. At this time, the balloon is sandwiched by the sandwiching rolls and the inner surface is pressed to form a laminated foam plate. In the co-extrusion compression bonding method, upon extruding the melt-kneaded product from the annular die, the melt-kneaded product made of the polycarbonate resin for the film layer, with respect to the foamable resin melt-kneaded product,
(1) When laminated on the outer peripheral surface and co-extruded, each layer of the polycarbonate resin film (A), the polycarbonate resin foam (B), the polycarbonate resin foam (B), and the polycarbonate resin film (A) is arranged in this order. A laminated foam is obtained, and (2) when laminated on both the outer peripheral surface and the inner peripheral surface and co-extruded, a polycarbonate resin film (A), a polycarbonate resin foam (B), a polycarbonate resin A laminated polycarbonate resin foam in which the layers of the film (A ″), the polycarbonate resin foam (B), and the polycarbonate resin (A) are laminated in this order is obtained. In this case, the resin film (A ″) layer is composed of two layers. By using the co-extrusion pressure bonding method as described above, productivity can be significantly improved. In addition, the obtained laminated polycarbonate resin foam plate also has stronger adhesion on the press-bonded surface, and as a result, mechanical properties such as bending strength are improved. In addition, the smoothness of the foam board is also improved, which is more preferable.

In this method, in order to foam the polycarbonate resin smoothly, it is advisable to add a cell regulator to the foamed resin kneaded product of the resin and a foaming agent, if necessary. In this case, as the cell regulator, inorganic powders such as talc and silica, acidic salts of polyvalent carboxylic acids, and mixtures of polyvalent carboxylic acids and sodium bicarbonate are preferable. The amount of addition is 0.01 to 5.0 parts by weight, preferably 0.05 to 0.5 parts by weight, per 100 parts by weight of the resin. If the amount is less than 0.01 part by weight, it is difficult to effectively foam the polycarbonate resin, while 5.0
If the amount is more than the weight part, the toughness of the obtained foam molded article may be reduced.

Further, in the foamed resin melt-kneaded product and / or the film layer resin melt-kneaded product, a flame retardant, a heat stabilizer, a weather resistance improver, a colorant, an antistatic agent, a conductivity imparting agent, etc. As described above, known additives that are added to ordinary foamed sheets and the like can be added. In addition, inorganic hydroxides such as aluminum hydroxide, calcium hydroxide, and magnesium hydroxide; inorganic carbonates such as calcium carbonate, magnesium carbonate, and barium carbonate; inorganic sulfites such as calcium sulfite and magnesium sulfite; calcium sulfate; and magnesium sulfate. 5-30% by weight of inorganic sulfates such as aluminum sulfate, inorganic oxides such as calcium oxide, aluminum oxide and silicon oxide, viscosities such as talc, clay, kaolin and zeolite or inorganic fillers such as natural minerals. Is also good.

Next, usually, the laminated foam board obtained as described above is cut to a predetermined length in the extrusion direction. The laminated foam board may be wound into a roll, depending on its thickness.

The laminated polycarbonate resin foam of the present invention
The board is made of the polycarbonate resin film (A) and
The thickness of the (A ′) layer is preferably 10 to 750 μm, respectively.
Or 30-300 μm, its polycarbonate resin
The thickness of the oil film (A ″) layer is 10 to 1500 μm,
Preferably 80-1000 μm, polycarbonate-based
The densities of the resin foam (B) and (B ') layers are each 0.1.
06-0.6g / cm ^Three, Preferably 0.08 to 0.3
g / cm^Three, Each having a thickness of 0.5 to 15 mm,
Preferably 1 to 10 mm, polycarbonate of the surface layer of the foam board
Center line of the surface of the resin-based resin films (A) and (A ')
Average roughness is 3.0 μm or less, preferably 2.5 μm or less
Below, and the bending strength Y (kg / cm^Two) Is below
It satisfies the notation. Y> 266X^Two+ 147X (where X is the apparent density of the foam plate (g / cm^Three)
You. Here, the apparent density (g / cm^Three)When
Is the weight (g) of the laminated polycarbonate resin foam board.
Volume (cm^Three). In the present specification, the center line average roughness of the surface is J
At a cutoff value of 0.8 mm based on IS B0601
A value obtained by measurement. In this specification,
Flexural strength Y of polycarbonate resin foam board is JIS
According to K7171, bending speed 100 mm / min, jig tip
End R5mm, span interval 100mm, test piece (width 50m
mx length x 150mm x laminated polycarbonate resin
(Thickness of the foam plate).

In the laminated polycarbonate resin foam board, if the thickness of the resin films (A) and (A ') is less than 10 μm, the effect of improving the strength such as bending is insufficient. In the case of extrusion, since the amount of resin in the resin films (A) and (A ') is too large relative to the amount of resin constituting the foam layer, the extrusion temperature becomes too high and extrusion foaming becomes difficult. In addition, the light weight and productivity of the laminated foam board are reduced. Further, if the thickness of the resin film (A ″) layer is less than 10 μm, the effect of further improving strength such as bending cannot be expected. On the other hand, 1500 μm
If it exceeds 300, it is not preferable in terms of lightness and productivity, and it may be difficult to obtain a good laminated foamed plate by the co-extrusion method.

When the density of the polycarbonate resin foams (B) and (B ′) is less than 0.06 g / cm ³ ,
Insufficient in rigidity and surface smoothness, 0.6
If it exceeds g / cm ³ , the lightness, cushioning property and heat insulating property will be insufficient. If the thickness of the polycarbonate resin foams (B) and (B ') is less than 0.5 mm, the rigidity is insufficient. If the thickness exceeds 15 mm, the production is difficult unless a special flat die is used. In addition, when an attempt is made to obtain a forcibly by using an annular die, poor appearance occurs.

If the center line average roughness of the surface of the polycarbonate resin film (A) or (A ') layer of the surface layer of the foamed plate exceeds 3 μm, the printability and appearance deteriorate. Although the lower limit is not particularly limited, it is usually 0.5 μm. Furthermore, those in which the bending strength Y of the foamed plate does not satisfy the above formula are those in which the effect of improving the strength by the laminated structure has not been achieved. The center line average roughness is adjusted by the melt tension of the base resin of the resin film (A) and the layer (A '), the bubble diameter of the foam (B) and the surface of the layer (B'), and the like. Further, the bending strength Y is as follows:
It is adjusted by the melt tension of the base resin of the layers (A ′) and (A ″), the adhesive strength between the film layer and the foams (B) and (B ′), and the like.

In the laminated polycarbonate resin foam plate of the present invention, the thickness of the polycarbonate resin foam (B) and (B ') layer from the interface with the polycarbonate resin film (A) or (A') layer. 100 in the direction
The relationship between the average cell diameter C in the width direction in the part of μm and the average cell diameter D in the width direction in the central part of the polycarbonate resin foam (B) or (B ′) layer in the thickness direction is C. /D≧0.5, and C / D
It is more preferable that ≧ 0.7. If C / D is too small, problems such as warpage occur. When the value of C / D is 0.5 or less, the closed cell ratio of the foam (B) or (B ′) layer may be low. Although the upper limit is not particularly limited, it is usually 1.0. The C / D is adjusted by conditions such as the lip interval of the extruder die, extrusion foaming temperature, and cooling after extrusion.

The laminated polycarbonate resin foam board of the present invention is lightweight, has a good surface appearance and a smooth surface, has excellent bending strength, hardly warps, and has impact resistance and heat resistance at extremely low temperatures. Because of its excellent properties, smoothness, mechanical strength, and toughness, it is useful as a base material in the packaging field, construction field, civil engineering field, etc., construction material, etc., and especially for wall members (side walls, It is extremely useful as a base material for the bottom wall.

By using the laminated polycarbonate resin foam board of the present invention as a base material, the following box can be produced (however, the present invention is not limited to these boxes only). A heat-sealing box in which a bottom member and a side member are coupled and assembled by bending them, and a heat-sealing box made of a laminated polycarbonate resin foam plate in which a joint portion of each member of the box is heat-sealed. Fusion box. An assembling box comprising a laminated polycarbonate resin foam plate in which a joining portion of each member of the box uses an adhesive, uses a joining fitting, or is fixedly connected by rivets. An assembling box made of a laminated polycarbonate resin foam plate, which is assembled by connecting four side members, a bottom member and / or a top member by a fitting mechanism formed at an edge thereof. A folding box that can be folded flat, at least two opposing side members are vertically divided into at least two parts, and the divided parts are connected by a hinge mechanism, and the connection part is foldable outward or inward. A folding box made of a laminated polycarbonate resin foam board.

The box body of the present invention is easy to produce because the laminated polycarbonate resin foam board as the base material has a good surface appearance, a smooth surface, excellent bending strength, and almost no warpage. The finish is beautiful and robust. In addition, since the laminated polycarbonate resin has such excellent properties as described above, it is possible to store, for example, foods that are still hot in the box, and further store it in a refrigerator or freezer and refrigerate or freeze it. You can also.

[0024]

Next, the present invention will be described in more detail by way of examples.

Examples 1-3, Comparative Example 1 A raw material resin obtained by adding 0.8 to 1.0% by weight of talc as a nucleating agent to a polycarbonate resin shown in Table 1 using bisphenol A was used in an extruder. After heating, melting, and kneading, normal pentane as a foaming agent was press-kneaded into an extruder, and on the other hand, bisphenol A was used.
Melt kneading the polycarbonate resin shown in the other extruder, co-extruding both kneaded material using an annular die such that the latter melt kneaded material is laminated on the outer periphery of the former melt kneaded material, cylindrical It is a foam. The outside of the cylindrical foam was cooled with air, and while the inside of the foam was in a press-fit state, the cylindrical foam was sandwiched by the pressing rolls and the inside of the foam was adhered and sufficiently cooled and solidified. Thereafter, by trimming both ends in the width direction, and further cutting in the width direction every 1000 mm in the extrusion direction, a laminated polycarbonate resin foam plate in which each layer of the film A, the foam B, the foam B ', and the film A' are sequentially laminated is obtained. Obtained.

Example 4 A starting resin obtained by adding 0.8% by weight of talc as a nucleating agent to a polycarbonate resin shown in Table 1 using bisphenol A was heated, melted and kneaded in an extruder, and further foamed. Normal pentane was pressed and kneaded into the extruder as an agent to obtain a foamable melt-kneaded product. The kneaded material is extruded from an annular die at the tip of an extruder to form a cylindrical foam. The outside of the foam is cooled by air, and while the inside of the foam is in a press-fit state, the cylindrical foam is sandwiched by a narrow pressure roll, the inside of the foam is adhered, and the foam is sufficiently cooled and solidified. (B) (B ')
To obtain a laminated foam board. On both sides of the obtained foam board,
The melt-kneaded product obtained by melt-kneading the polycarbonate resin shown in Table 1 using bisphenol A in another extruder was extruded, laminated and cooled and solidified sufficiently, and both ends in the width direction were trimmed. By cutting in the width direction each time, a laminated polycarbonate resin foam plate in which each layer of the film (A), the foam (B), the foam (B ′), and the film (A ′) was sequentially laminated was obtained.
The physical properties and evaluation of the laminated polycarbonate resin foam board were as shown in Table 1.

Comparative Examples 2 and 3 The same operation as in Example 4 was carried out except that the extrusion lamination was not carried out, to obtain a laminated foam plate in which the foam (B) and the foam (B ') were laminated. The physical properties and evaluation of this foam board were as shown in Table 1.

The measurement and evaluation of each physical property value in the above Examples and Comparative Examples were performed as follows. [Center line average roughness] Using a surface roughness measuring device Surfcoder 30D manufactured by Kosaka Laboratory Co., Ltd., a vertical magnification of 500, a horizontal magnification of 10, and a reference length of 8.00 m based on JISB0601.
m, cut-off value 0.8 mm, stylus tip radius 2 μm, and feed rate 0.1 mm / sec. The center line average roughness of both sides of the foam plate was measured, and the larger value was shown in Table 1. . [Bending strength of foam board] UTMII manufactured by Toyo Baldwin
Using an I type, in accordance with JIS K7171, bending speed 100 mm / min, R5 mm at the jig tip, span interval 10
The measurement was performed under the following conditions: 0 mm, test piece width 50 mm, length 150 mm, and laminated foam plate thickness. [Average Cell Diameters C and D of the Foam Board] In the polycarbonate resin foam (B) and (B ′) layers constituting the foam board of the enlarged view of the cross section perpendicular to the thickness direction in the width direction of the foam board, the polycarbonate resin film A length 3 at a position corresponding to a portion of 100 μm in the thickness direction from the lamination interface with the (A) or (A ′) layer (Comparative Example 2, 3 foam board surface)
A reference line corresponding to 000 μm is drawn in the width direction. Next, the number (bubbles) of bubbles on the reference line was counted, and the average bubble diameter C was determined by the following equation. In addition, a reference line corresponding to a length of 3000 μm in the width direction is placed at a position where the thickness of the polycarbonate resin foam (B) and (B ′) layers in the enlarged view of the vertical section in the thickness direction in the width direction of the foam plate is divided into two. Pull. Next, the number (bubbles) of the bubbles on the reference line was counted, and the average bubble diameter D was determined by the following equation. [Smoothness of foamed board] The smoothness was evaluated by the warp value of the foamed board.・ ・ ・: The warp value is 15 mm or less × ・ ・ ・ 〃 Super The warp value of the foamed board refers to the direction of 500 mm in the extrusion direction of the sheet-like foam and the width of the foam in the direction orthogonal to the extrusion direction. A foamed sample for measurement was cut into a shape (with the same thickness), a sample was placed on a horizontal plate member with a larger area than this, and the sample was placed in a state where no force other than its own weight was applied. Turn upside down and measure the length of the perpendicular dropped from the tallest part of the sample to the horizontal plate-like member in the same standing state, and subtract the sample thickness from the measured perpendicular length. It means the larger value (mm) of each of the front and back values.

[0029]

[Table 1]

[0030]

Industrial Applicability The laminated polycarbonate resin foam plate of the present invention is lightweight, has a good surface appearance, has a smooth surface, has excellent bending strength, has almost no warpage, and is particularly useful for producing boxes and the like. It is extremely useful as a base material. In addition, a box manufactured using the polycarbonate resin foam plate can be stored, for example, while food is hot, and can be refrigerated or frozen directly in a refrigerator or a freezer as it is, which is extremely convenient. Things.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29L 9:00 (72) Inventor Satoshi Iwasaki 3271-19, Tsuruta-cho, Utsunomiya-shi, Tochigi Prefecture Corpora 2-101, Tsuruta (72) Inventor Seiji Takahashi 1704-25 Tsuruta-cho, Utsunomiya City, Tochigi Prefecture Terrace House A-102

Claims (6)

[Claims] 1. Each layer of (i) a polycarbonate resin film or sheet (A), a polycarbonate resin foam (B), a polycarbonate resin foam (B ′), and a polycarbonate resin film or sheet (A ′) Laminated in this order, or (ii) polycarbonate resin film or sheet (A), polycarbonate resin foam (B), polycarbonate resin film or sheet (A ″), polycarbonate resin foam (B ′) ) And a polycarbonate resin film or sheet (A ′) having a structure in which each layer is laminated in this order, wherein the polycarbonate resin film or sheet (A) and the (A ′) layer Of polycarbonate-based resin forming
The melt tension at 2.0 ° C. is 2.0 g or more, the thickness of the polycarbonate resin film or sheet (A) and the layer (A ′) is 10 to 750 μm, respectively, and the thickness of the polycarbonate resin film or sheet (A ″) layer is 10
1500 μm, and the densities of the polycarbonate resin foam (B) and (B ′) layers are 0.06 to 0.
6 g / cm ³ and its thickness is 0.5 to 15 m each
m, the center line average roughness of the surface of the polycarbonate resin film or sheet (A) or (A ′) layer of the surface layer of the foamed board is 3.0 μm or less, and the bending strength Y (kg
/ Cm ² ) satisfies the following formula: Y> 266X ² + 147X (where X represents the apparent density (g / cm ³ ) of the foamed board) 2. The polycarbonate resin film or sheet (A ′) layer has the same composition as the polycarbonate resin film or sheet (A) layer, and the polycarbonate resin foam (B ′) layer has a polycarbonate resin foam. The laminated polycarbonate resin foam board according to claim 1, which has the same composition as the layer (B). 3. The laminated polycarbonate resin foam board according to claim 1, wherein the polycarbonate resin film or sheet and the polycarbonate resin foam are laminated and bonded by a co-extrusion method. 4. A resin for a foam comprising a foaming agent-containing polycarbonate resin having a melt tension at 250 ° C. of 2.0
g or more of a resin for a film or sheet made of a polycarbonate resin, and the latter is co-extruded using an annular die so that the latter is laminated on the outer peripheral surface or the outer peripheral surface and the inner peripheral surface of the former. A method for producing a laminated polycarbonate resin foam board, comprising: a step of forming a foam; and a step of fusing inner surfaces of the foam to each other to form a foam board. 5. The melt viscosity of the polycarbonate resin for a foam at a temperature of 250 ° C. and a shear rate of 100 sec ⁻¹ is 5 ×.
10 ⁴ a to 2 × 10 ⁵ poise and the temperature 250 ° C. of the film or polycarbonate resin sheet, according to claim 4, wherein the melt viscosity at a shear rate of 100 sec ^-1 is 5 × 10 ³ to 2 × 10 ⁵ poise Of producing a laminated polycarbonate resin foam board. 6. A box comprising the laminated polycarbonate resin foam plate according to claim 1 as a base material.