JP2002219781A - Laminated foam molded article of polypropylene resin, laminated foam used for the production thereof, and method of producing the same - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To have heat resistance, oil resistance, heat insulation properties and excellent rigidity at high temperatures that can be used for microwave cooking, etc., and to have a sufficiently matte and calm surface. Provided is a laminated foam molded article of a polypropylene resin having a texture and a unique beautiful appearance, a laminated foam suitable for the production thereof, and an efficient production method thereof. SOLUTION: The laminated foam molded article has a surface layer 3 of a CPP film 30 via an intermediate layer 2 of an OPP film 20 on at least one side of a base layer 1 made of a foamed sheet 10 of a polypropylene resin. In the laminated foam molded article, the foam sheet 10, the OPP film 20, and the CPP film 30 were laminated in this order. In the manufacturing method, the respective layers are directly laminated and bonded by a thermal lamination method.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel laminated foam molded article of a polypropylene resin, a laminated foam used for the production thereof, and a method for producing the laminated foam.

[0002]

2. Description of the Related Art Conventionally, food packaging containers such as lunch boxes and bowls sold in convenience stores and supermarkets and other general packaging containers include heat insulation, heat insulation, and the like.
In consideration of strength and the like, those made of expanded polystyrene have been widely used. However, recently, food packaging containers have been required to have high heat resistance and oil resistance, which cannot be obtained with containers made of expanded polystyrene. This is due to the fact that heating and cooking services using microwave ovens, such as bento boxes, are becoming popular at convenience stores, and the diffusion rate of microwave ovens to ordinary households is increasing. This is due to the fact that opportunities for cooking by heating are increasing.

A non-foamed container made of a polypropylene sheet filled with a filler such as talc is generally used as a food packaging container having excellent heat resistance and oil resistance and capable of microwave cooking. However, since the above-mentioned container is not foamed, it has insufficient heat insulating properties. In particular, there is a problem that the wall surface and the bottom surface become hot when the container is taken out after heating and cooking in a microwave oven. There is also a problem that recycling is difficult due to the large amount of filler.

Therefore, it has been studied to manufacture a food packaging container by thermoforming a foamed sheet of a polypropylene resin. The foamed sheet of the polypropylene-based resin has an excellent heat insulating property because it has a foamed structure like foamed polystyrene. In addition, they are excellent in heat resistance and oil resistance as compared with expanded polystyrene, and are also excellent in recyclability because they do not contain a large amount of filler in most cases. However, a container manufactured by thermoforming a polypropylene-based resin foam sheet alone has low rigidity, and its strength is greatly reduced particularly in a high temperature state after cooking by heating in a microwave oven. For this reason, for example, in a container having a wide opening such as a lunch container, a noodle container, a curry container, and a pasta container, there is a problem that the entire container is bent or deformed by the weight of the content, and the content is easily spilled. Therefore, at present, the weight and weight of the foamed sheet are increased to cope with bending and deformation at a high temperature. However, this raises a new problem that the cost of the container is increased.

When a container is manufactured by thermoforming the foamed sheet of the polypropylene-based resin, a drawdown in which the sheet droops greatly in a heating zone of the molding apparatus, and a corrugated sheet is likely to occur. Further, there is also a problem that heating of the sheet becomes non-uniform and a good container cannot be manufactured. In particular, this tendency is stronger in a foam sheet having a larger basis weight. In order to solve such a problem of a polypropylene-based resin foam sheet alone, it is proposed to use a laminated foam in which biaxially oriented polypropylene-based resin films (hereinafter abbreviated as “OPP films”) of the same type are laminated. (Japanese Patent No. 290)
No. 4337, JP-A-11-170455, etc.).

[0006] Such a laminated foam improves the rigidity of the container at a high temperature by laminating an OPP film, so that it is prevented from being greatly bent or deformed during heating and cooking. In addition, since the basis weight of the foamed sheet can be reduced by this lamination, it is considered that the problem in the manufacturing process can be solved.

[0007]

However, according to studies by the present inventors, it has been found that a laminated foam molded article such as a container manufactured from the above-mentioned conventional laminated foam has a calm surface which is too glossy. It became clear that there was a problem that the texture could not be obtained. The gloss of the surface can be suppressed to some extent by increasing the conditions for producing a laminated foam by laminating a foamed sheet and an OPP film, particularly by increasing the amount of heat received by the OPP film during lamination. Also, the gloss of the surface can be suppressed to some extent by increasing the amount of heat received by the OPP film when the manufactured laminated foam is thermoformed to produce a laminated foam molded article. However, nonetheless, the surface of the molded article cannot be a sufficiently matte, calm texture.

[0008] In addition to the above-mentioned method, there is also a problem that the degree of change in gloss with respect to the amount of heat applied varies and varies depending on various factors such as characteristics of a foamed sheet and an OPP film forming a laminate. is there. For example, the extrusion direction (MD direction) of the resin, especially on the laminate
The degree of change in gloss with respect to the amount of heat applied varies depending on differences in the position in the width direction (TD direction) intersecting with, the difference in the density of the foam sheet, the thickness of the OPP film, the type of the base resin, and the like. For this reason, it is difficult to stably produce a molded article having a substantially uniform degree of matting only by controlling the amount of heat during lamination or thermoforming.

It is an object of the present invention to provide heat resistance, oil resistance, heat insulation and high rigidity at high temperatures which can be used for microwave cooking and the like, and the surface is sufficiently matte and calm. An object of the present invention is to provide a laminated foam molded article of a polypropylene resin having a texture and a unique and beautiful appearance that has never been seen before. Another object of the present invention is to provide a laminated foam capable of stably producing the above-mentioned laminated foam molded article while maintaining a constant degree of matting on the surface.

[0010] It is still another object of the present invention to provide a method for efficiently producing the above-mentioned laminated foam.

[0011]

Means for Solving the Problems To solve the above-mentioned problems, a laminated foam molded article of a polypropylene resin according to the present invention is provided on at least one surface of a base material layer formed of a foamed sheet of a polypropylene resin by a biaxially stretched polypropylene. It has a surface layer of an unstretched polypropylene resin film via an intermediate layer of the resin film. In such a laminated foamed molded article, the surface layer of the unstretched polypropylene resin film (hereinafter abbreviated as “CPP film”) and the intermediate layer of the OPP film thereunder synergistically act to make the surface of the surface layer moderately glossy. It will be erased. That is, the CPP film reduces the gloss of the OPP film and the gloss of the OPP film
It acts to prevent the film from becoming too dull. Then, the surface has a sufficiently matte and calm texture that cannot be obtained by the conventional surface obtained by adjusting the amount of heat applied to the OPP film. Moreover, this surface state appears almost uniformly over the entire surface layer. Therefore, the laminated foam molded article of the present invention has a unique and beautiful appearance which has never been seen before.

Further, since the laminated foamed molded article of the present invention is entirely formed of a polypropylene resin, it has heat resistance and oil resistance that can be used for microwave cooking and the like, and in most cases a large amount of Because it does not contain fillers, it has excellent recyclability. In addition, since it contains a foamed sheet, it has high heat insulation properties, and since it is mainly reinforced by an OPP film, it has excellent rigidity at high temperatures.
For producing the laminated foam molded article, the laminated foam of the present invention is obtained by laminating a non-oriented polypropylene resin film on at least one surface of a polypropylene resin foam sheet via a biaxially oriented polypropylene resin film. It is characterized by the following.

Such a laminated foam has a calm texture in which the entire surface of the CPP film is sufficiently and uniformly matted by the synergistic action of the CPP film and the OPP film thereunder. . Moreover, this surface state is different from the conventional surface state obtained by adjusting the amount of heat applied to the OPP film, and is different from the state of the amount of heat applied at the time of thermoforming or the difference in characteristics of each layer constituting the laminated foam. There is no significant change. Therefore, according to the laminated foam of the present invention, it is possible to stably produce a laminated foam molded article having a unique beautiful appearance as described above, while maintaining a constant degree of matte surface.

The method of the present invention for producing the above-mentioned laminated foam is a method of directly laminating a foam sheet, a biaxially oriented polypropylene resin film, and a non-oriented polypropylene resin film which have been prepared in advance by a thermal lamination method. It is characterized by bonding. According to the manufacturing method of the present invention, for example, the respective layers can be directly laminated and bonded without using a hot melt adhesive or the like, so that the layer configuration can be simplified and the cost of the laminated foam can be reduced. Further, a laminated foam can be produced by exposing each layer to a high temperature for a long period of time, for example, by heating only a very short time while passing between a hot roll and a nip roll as described later. For this reason, it is also possible to prevent a large stress from being accumulated in the OPP film, and to improve the thermoformability of the laminated foam in combination with the simplification of the layer configuration by omitting the adhesive as described above. Can also.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. <Laminated Foam and Method for Producing the Same> The laminated foam of the present invention is, for example, as shown in FIG. 2A, at least one side of a polypropylene resin foam sheet 10 (one side in the figure, but also includes both sides). ), A CPP film 30 is laminated via an OPP film 20. Such a laminated foam may have a print layer 4 as shown in FIG. 2 (b). The printing layer 4 is formed at the interface between the OPP film 20 and the CPP film 30 in the figure, but may be formed at the interface between the foam sheet 10 and the OPP film 20. Further, the print layer 4 may be formed on both interfaces.

In the laminated foam, as described above, the CPP film 30 and the OPP film
By the synergistic action with zero, the entire surface of the CPP film 30 is brought into a surface state having a calm texture that is sufficiently and uniformly matted. The surface state of the CPP film 30 is determined by the specular gloss of the surface (incident angle θ = 60).
°) and center line average roughness Ra.

Of these, the specular glossiness is preferably, but not limited to, 6 to 60. If the specular gloss is less than 6, the matte is too strong, and if the specular gloss is more than 60, the matte is insufficient and the gloss is too strong. May not be obtained. In consideration of further improvement in design, the specular glossiness of the surface of the CPP film 30 is preferably 40 or less in the above range.

The center line average roughness Ra is not limited to this, but is preferably 4 μm or less.
When the center line average roughness Ra exceeds 4 μm, there is a possibility that a calm texture cannot be obtained. In addition,
Considering further improvement in design, the center line average roughness R
a is preferably 3 μm or less in the above range. Incidentally, the lower limit of the center line average roughness Ra is, of course, 0 μm.

The specular gloss is measured according to Japanese Industrial Standard JIS Z8.
741 _-1997 It is measured by the following method according to the measuring method specified in "Specular glossiness-measuring method". That is,
The reflectance of the surface of the CPP film 30 is measured under the condition of an incident angle θ = 60 ° using a specular gloss measuring device conforming to the above standard. Next, this measured value is converted into a percentage number when the glossiness of the reference surface is set to 100, and is expressed as a specular glossiness. As the reference surface, a black glass reference surface having a constant refractive index of 1.567 over the entire visible wavelength range defined by the above standard is used, and when the incident angle θ = 60 °, the specular reflectance is 10%. The glossiness is defined as 100. However, recently, when the measurement is performed, the above conversion is automatically performed, and a specular gloss measuring device having a function of outputting the specular gloss (for example, a gloss meter manufactured by HORIBA, Ltd. Checker IG-330) is commercially available. If such a device is used, the above conversion work can be omitted.

On the other hand, the center line average roughness Ra is obtained by the following method. That is, first, a cross-sectional curve of the surface of the CPP film 30 is obtained by, for example, measuring using a surface roughness measuring device. Next, JIS B0601 was obtained from this sectional curve.
_{-1994 Calculate} the center line average roughness Ra based on the method specified in “Surface Roughness-Definition and Display”. When the center line average roughness Ra is also measured, a surface roughness measurement device having a function of automatically performing a calculation based on the above specified method and outputting the result (for example, Also, Handysurf E-35A manufactured by Tokyo Seimitsu Co., Ltd. used in Examples described later is commercially available. If such a measuring device is used, the operation of obtaining the center line average roughness Ra can be omitted.

The preferred ranges of the specular gloss and the center line average roughness Ra described above are the average values of the values measured for a plurality of samples of the same laminated foam. Even if the minimum value and / or the maximum value of the measured values are out of the preferred range, it can be said that the device has a good appearance if the average value is within the preferred range. This is due to the mirror glossiness and the center line average roughness Ra of the laminated foam molded article described later.
The same applies to. (Foam Sheet) As the polypropylene resin forming the foam sheet 10 of the laminated foam, a non-crosslinked polypropylene resin is preferable. Examples of the non-crosslinked polypropylene resin include (A) a polypropylene resin having a free terminal long chain branch in the molecule and a melt tension of 6 g or more and 40 g or less (hereinafter referred to as “resin (A)”), and (B) )
The melt tension is 0.01 g or more and less than 6 g, and the ratio of the weight average molecular weight Mw to the number average molecular weight Mn is Mw /
Polypropylene resin having Mn of 3 to 8 [hereinafter referred to as “resin
(B) ”] is preferably used.

The reason why the preferable range of the melt tension of the resin (A) is 6 g or more and 40 g or less is that if the melt tension is less than 6 g, good foaming properties cannot be obtained. On the other hand, if the melt tension exceeds 40 g, the fluidity may be extremely deteriorated or gel may be easily generated, and the extrudability may be reduced. The melt tension of the resin (A) is
In consideration of the balance between foamability and extrusion processability, it is particularly preferable that the weight be 20 to 30 g even within the above range.

Resins having such free-end long-chain branches
As (A), for example, the trade name Pro-, which is sold as a foaming grade by Montell SDK Sunrise, Inc.
fax PF-814, Pro-fax SD-632
And the like. The resin (A) has good foaming properties when foamed by extrusion foaming or the like. For example, foaming with a low density such as a density of less than 0.3 g / cm ³ , a high foaming ratio, and particularly excellent heat insulation properties. It is suitable for forming the sheet 10.

Therefore, the resin (A) may be used alone to form the foamed sheet 10, but the resin (A) is expensive and may increase the product cost. For this reason, it is usually preferable to form the foamed sheet 10 by using both the resin (A) and the resin (B) as the polypropylene resin. Also in this case, the foam sheet 10 having a relatively low density, a high expansion ratio, and excellent heat insulation properties can be formed. Resin (B)
The preferred range of the melt tension is 0.0 as described above.
The reason why the content is 1 g or more and less than 6 g is as follows.
That is, if the melt tension is less than 0.01 g, the tension is too low, and the resulting foamed sheet 10 tends to have an open cell structure. On the other hand, if it is 6 g or more, the melt viscosity of the resin increases, and it becomes difficult to lower the resin temperature to near the melting point. Therefore, in either case, the quality of the foam sheet 10 may be reduced. The melt tension of the resin (B) is preferably 0.1 g or more and less than 6 g, and more preferably 0.1 g or more and less than 3 g, even within the above range, in consideration of the balance between the tension and the melt viscosity. Is more preferred.

Examples of the resin (B) include general-purpose polypropylene resins such as propylene homopolymer and ethylene-propylene copolymer which satisfy the above conditions. The ratio of the resin (A) to the total amount of the resin (A) and the resin (B) is preferably from 10 to 50% by weight, and more preferably from 10 to 40% by weight. The reason is as follows.

That is, the resin (A) exerts the foaming property of a non-crosslinked general-purpose polypropylene resin, that is, a resin (B), which is usually not so good in foaming property, by the action of free long-chain branching introduced into the molecule. Has a function to improve. And it contributes to obtaining the foamed sheet 10 provided with heat insulation, oil resistance, and heat resistance. However, the polypropylene resin having a free-end long-chain branch has a problem that its rigidity is inferior to that of a general-purpose polypropylene resin having no free-end long-chain branch. Further, since the polypropylene-based resin having a free-end long-chain branch is expensive, the production cost of the product is increased.

Therefore, the ratio of the resin (A) to the total amount of the resin (A) and the resin (B) is preferably not more than 50% by weight, particularly preferably not more than 40% by weight as described above. On the other hand, by improving the foaming property of the resin (B) described above,
As in the case of (A) alone, in order to form a foam sheet 10 having a low density of less than 0.3 g / cm ³ , a high expansion ratio, and excellent heat insulation properties, the resin (A) and the resin (A) Resin (A) accounts for 10% by weight of the total amount with (B).
It is preferable that this is the case.

As described above, the resin (B) usually has a poor foaming property, but has a density of, for example, 0.1.
It is possible to manufacture a foam sheet 10 having a relatively low expansion ratio of ³ g / cm ³ or more. Therefore,
The foamed sheet 10 may be formed by using the resin (B) alone as the polypropylene resin. The foam sheet 10
The above polypropylene resin is produced by, for example, melt-kneading with a foaming agent using an extruder, and then extruding and foaming through a mold connected to the tip of the extruder.

The die includes a circular slit die, a T-die, and the like. A cylindrical foam extruded and foamed through a circular slit die is cut at one or more locations on the circumference to form a foam. Preferably, sheet 10 is manufactured. Examples of the foaming agent used for extrusion foaming include various volatile foaming agents and decomposable foaming agents, carbon dioxide, nitrogen gas, water and the like. Among them, examples of the volatile foaming agent include one or more of hydrocarbons such as propane, butane, and pentane, and halogenated hydrocarbons such as tetrafluoroethane, chlorodifluoroethane, and difluoroethane. It is preferably used. As butane, normal butane or isobutane may be used alone, or normal butane and isobutane may be used in an optional ratio.

Examples of the decomposable foaming agent include a combination of an organic foaming agent such as azodicarbonamide and dinitrosopentamethylenetetramine, an organic acid such as citric acid or a salt thereof, and a bicarbonate such as sodium bicarbonate. And inorganic foaming agents. One of these foaming agents may be used alone, or two or more thereof may be used in combination.

Various additives may be appropriately added to the polypropylene resin in advance or at the time of melt-kneading with an extruder as long as the effects of the present invention are not impaired. Examples of the additive include a bubble regulator such as talc, or citric acid and sodium bicarbonate, for adjusting the size of bubbles during foaming, a pigment, a stabilizer, a filler, and an antistatic agent. . Of these, the filler
It is added in order to improve the strength, rigidity at high temperature, durability and heat resistance of the molded article. Such fillers include, for example, inorganic fillers such as talc, calcium carbonate, silica, alumina, titanium oxide and clay. The inorganic filler can be blended at a ratio of about 5 to 50 parts by weight based on 100 parts by weight of the polypropylene resin. However, considering the recyclability as described above, it is preferable that the compounding amount of the filler is as small as possible, and it is ideal not to mix it at all.

The foam sheet 10 thus formed is
Has a density of 0.1 to 0.85 g / cm ^ThreePreferably
No. The density of the foam sheet 10 is 0.1 g / cm^ThreeLess than
May reduce the strength of the molded product and the rigidity at high temperatures.
0.85g / cm^ThreeIf more than
There is a possibility that the heat insulating property of the resin may decrease. The foam sheet 10
Density is a balance between strength and rigidity of the molded product and heat insulation
In consideration of the above, even within the above range, especially 0.18 to 0.6
g / cm^ThreeIt is preferred that

The thickness of the foamed sheet 10 is preferably 0.3 to 5 mm, and preferably 0.5 to 3 mm in consideration of thermoformability, although it depends on the specification of the target molded product. More preferred. (OPP film) Examples of the polypropylene-based resin from which the OPP film 20 is based include a homopolymer of propylene, and a block copolymer of propylene and another resin or a random copolymer alone. ,
Alternatively, two or more kinds are used in combination.

Other resins other than propylene include, for example, ethylene and α-olefins (1 to 4) having 4 to 10 carbon atoms.
-Butene, 1-pentene, 1-hexene, 4-methyl-
Olefins such as 1-pentene). Particularly suitable polypropylene resins include, for example, propylene homopolymer, propylene-
Ethylene random copolymer, propylene-ethylene-α
-An olefin random copolymer, and a block copolymer containing a propylene component and a propylene-ethylene random copolymer component.

The polypropylene resin may be mixed with another resin as long as the effects of the present invention are not impaired.
Examples of the other resin include homopolymers or copolymers such as ethylene and α-olefin, olefin resins such as polyolefin wax and polyolefin elastomer, petroleum resins, and hydrocarbon resins such as terpene resins. Are used singly or as a mixture of two or more.

Various additives may be added to the polypropylene-based resin as needed, as long as the effects of the present invention are not impaired. As additives, for example, antistatic agents, antifogging agents, antiblocking agents, antioxidants,
Light stabilizers, crystal nucleating agents, lubricants, surfactants for imparting slip and anti-blocking properties, fillers and the like can be mentioned. To manufacture the OPP film 20,
First, a polypropylene resin is melt-kneaded using an extruder, and then extruded into a film through a mold connected to the tip of the extruder. And extruded film,
The OPP film 20 is stretched (biaxially stretched) sequentially or simultaneously in two directions of a resin extrusion direction (longitudinal direction, MD) and a direction perpendicular thereto (lateral direction, TD).
Is manufactured.

In the sequential biaxial stretching method described above, first, a molten resin is extruded into a film from a T-die connected to the tip of the extruder using an extruder, and is cooled and solidified on a cooling roll. Next, after stretching in the MD direction using a hot roll stretching machine, stretching in the TD direction using a tenter transverse stretching machine is performed. Examples of the simultaneous biaxial stretching method include a tenter method and a tubular inflation method. Although the amount of stretching of the OPP film 20 is not particularly limited, the area stretching ratio, that is, the area stretching ratio = (stretching ratio in MD direction) × (stretching ratio in TD direction) is preferably 4 to 50 times.

If the area stretching ratio is less than 4 times, the effect of improving the drawdown of the laminated foam due to the lamination of the OPP film 20, or the effect of improving the strength, rigidity at high temperature, etc. of the molded product is not obtained. May be sufficient.
On the other hand, if the area stretching ratio exceeds 50 times, the thermoformability of the laminated foam may be reduced. The area stretch ratio is particularly preferably 15 to 35 even in the above range in consideration of the balance between the effect of improving the drawdown, the effect of improving the strength and rigidity of the molded product, and the thermoformability of the laminated foam.
Preferably it is twice.

The stretching ratio in the MD and TD directions is preferably 2 to 10 times. If the stretching ratio is less than 2 times, the effect of improving the drawdown of the laminated foam due to the lamination of the OPP film 20, or the effect of improving the strength, rigidity at high temperature, etc. of the molded product may be insufficient. There is. On the other hand, when the stretching ratio exceeds 10 times, the thermoformability of the laminated foam may be reduced. The draw ratio in the MD direction and the TD direction is particularly within the above range in consideration of the balance between the effect of improving the drawdown, the effect of improving the strength and rigidity of the molded product, and the thermoformability of the laminated foam. It is preferably 3 to 9 times.

The thickness of the OPP film 20 is 5 to 50 μm.
m is preferred. If the thickness is less than 5 μm, the effect of improving the drawdown of the laminated foam and preventing the occurrence of corrugation and the effect of improving the rigidity of the molded product at high temperatures may be insufficient. Conversely, the thickness is 50μ
When the thickness exceeds m, it is often used when the OPP film 20 is laminated with the foam sheet 10 and the CPP film 30 to produce a laminated foam, or when the produced laminated foam is thermoformed to produce a molded product. Of heat. For this reason, the manufacturing efficiency may be deteriorated. Further, the appearance of the molded article may be deteriorated, for example, because the foamed sheet 10 is invaded by the heat and a locally elongated portion is formed during the thermoforming. The thickness of the OPP film 20 is particularly preferably 6 to 45 μm even within the above range in consideration of the balance between the above-mentioned properties.
m is preferred.

Further, a general OPP film formed of, for example, a homopolymer of propylene has a low elongation at the time of thermoforming. Therefore, the thermoforming property tends to decrease as the thickness increases. In addition, the OPP film has excellent mechanical strength, and can exhibit sufficient strength even with a small thickness. Therefore, when a general OPP film is used, the smaller its thickness is, the more preferable it is within the above range. Taking into account the balance between mechanical strength and thermoformability, the preferred range is about 6 to 25 μm.

Recently, an OPP film has been developed in which the mechanical strength is slightly lower than that of a general OPP film, but the elongation is remarkably improved. Such an OPP film has a propylene-ethylene random copolymer having an ethylene content of 1 to 4% by weight, or an ethylene content of 0.5 to 3.0% by weight and a 1-butene content of 4 to 15% by weight. It is formed of a propylene copolymer having a relatively low melting point, such as a propylene-ethylene-1-butene random copolymer (JP-A-7-241906). Therefore, elongation at the time of thermoforming is better than that of a general OPP film, and deep drawing and the like are possible, and a good molded product can be obtained. However, as described above, since the mechanical strength is slightly low, in order to manufacture a molded article having sufficient strength and rigidity, it is preferable that the thickness be as large as possible within the above range. Its preferred range is 20-45 μm
It is about.

The surface of the OPP film 20 may be subjected to a surface treatment such as a corona discharge treatment in order to improve printability and the like. The OPP film 20 is not limited to a single layer. For example, a laminated film in which two or more OPP films are laminated, such as OPP films made of polypropylene resins having different compositions or OPP films having different stretching ratios, can be used. In that case, it is preferable to set the thickness of each layer so that the total thickness of all the OPP films falls within the above-described preferred range.

The OPP film 20 is laminated with another film having a different composition such as a film made of an ethylene-vinyl alcohol copolymer for the purpose of improving gas barrier properties, for example, within a range not to impair the effects of the present invention. May be. (CPP film) As the polypropylene-based resin from which the CPP film 30 is based, the same polypropylene-based resin as that of the OPP film 20 can be used. The same applies to the point that other resins can be mixed with the polypropylene resin within a range that does not impair the effects of the invention. Further, the types of other resins are the same as in the case described above. Further, the types of additives that may be added to the polypropylene-based resin are the same as in the previous case.

The CPP film 30 is produced by melt-kneading a polypropylene-based resin using an extruder, and then substantially extruding a film extruded through a mold connected to the tip of the extruder. CPP film 30
Preferably has a thickness of 5 to 80 μm. Thickness 5
If it is less than μm, the above-described effect of reducing the gloss of the OPP film 20 cannot be sufficiently obtained, and the matte may be insufficient, and a calm texture may not be obtained.
On the other hand, when the thickness exceeds 80 μm, the matting is too strong, and there is a possibility that a calm texture cannot be obtained. Further, the CPP film 30 is replaced with the foam sheet 10, O
A large amount of heat is required when a laminated foam is produced by laminating with the PP film 20 or when a molded article is produced by thermoforming the produced laminated foam. For this reason, the manufacturing efficiency may be deteriorated. Further, the appearance of the molded article may be deteriorated, for example, because the foamed sheet 10 is invaded by the heat and a locally elongated portion is formed during the thermoforming. Note that C
The thickness of the PP film 30 is preferably 10 to 50 μm even in the above range, in consideration of the balance between the above properties.

The thickness of the CPP film 30 is OPP.
It is preferably 40 to 500% of the thickness of the film 20. Below the above range, the above-mentioned CPP film 3
If 0, the effect of reducing the gloss of the OPP film 20 cannot be sufficiently obtained, and the matte may be insufficient, so that a calm texture may not be obtained. On the other hand, if it exceeds the above range, the effect of the OPP film 20 is relatively weakened, and as a result, drawdown or corrugation may easily occur in the laminated foam during thermoforming. In addition, there is a possibility that the effect of improving the rigidity of the molded product at high temperatures may be insufficient. Further, the matte may be too strong to provide a calm texture. In addition, the thickness of the CPP film 30 is preferably 50 to 450% of the thickness of the OPP film 20 even in the above range in consideration of the balance between the above effects.

The surface of the CPP film 30 may be subjected to a surface treatment such as a corona discharge treatment in order to improve, for example, printability. The CPP film 30 is not limited to a single layer. For example, a laminated film in which two or more CPP films are laminated, such as CPP films made of polypropylene resins having different compositions, can be used.
In that case, it is preferable to set the thickness of each layer so that the total thickness of all the CPP films falls within the above-described preferred range.

As in the case of the OPP film 20, another film having a different composition such as a film made of an ethylene-vinyl alcohol copolymer is laminated on the CPP film 30 for the purpose of improving gas barrier properties and the like. You may. The total thickness of the CPP film 30 and the OPP film 20 laminated thereon is 20 to 1
It is preferably 20 μm. If the thickness is less than 20 μm, the effect of improving the strength of the molded product and the rigidity at high temperatures may be insufficient. Conversely, if it exceeds 120 μm, a large amount of heat is required when thermoforming the laminated foam,
There is a possibility that the appearance of the molded article is deteriorated, for example, because the foamed sheet 10 is invaded by heat and a locally elongated portion is formed during thermoforming. OPP film 20 and CP
In consideration of the balance of these properties, the total thickness of the P film 30 is preferably 30 to 90 μm even within the above range.

(Printed Layer 4) The printed layer 4 for improving the design and the like is formed at any one of the interfaces of the respective layers located between the foamed sheet 10 and the CPP film 30. Specifically, as described above, the interface between the CPP film 30 and the OPP film 20 or the foam sheet 10 and the OPP film
It is formed on one or both of the interfaces with the film 20. More specifically, (i) OPP film 20
(Ii) Surface of the CPP film 30 on the OPP film 20 side, (iii) OP
The printing layer 4 is formed in advance on any of the surface of the P film 20 on the side of the foam sheet 10 and (iv) the surface of the foam sheet 10 on the side of the OPP film 20 prior to lamination, and then laminated. By bonding, the print layer 4 is formed at the predetermined position.

Of these, the formation of the printing layer 4 on any one of the surfaces (i) to (iii) except for the surface of the foamed sheet 10 (iv) provides excellent printing with excellent smoothness. It is preferable because it can be applied. In the above configurations (i) to (iv), the printing layer 4 is made of a transparent or translucent and moderately matte CP.
It will be seen through the surface of the P film 30. For this reason, a beautiful appearance is obtained in combination with the calm texture of the CPP film 30. This appearance is retained even in a molded product after thermoforming, so that a molded product excellent in design properties can be obtained.

For example, if the wood grain print layer 4 is formed on any of the above-mentioned surfaces by gravure printing or the like, a molded article having the appearance and texture of an actual white wood, in combination with the moderate matting of the CPP film 30. Is obtained. In addition, by kneading and coloring a layer serving as a base of the printing layer 4 with a pigment, a more beautiful appearance can be formed together with the printing layer 4. Further, by forming the printing layer 4 at two interfaces that can be seen from the outside of the same CPP film 30, a more beautiful appearance can be formed by overlapping the two printing layers 4. Further, the foamed sheet 10, the OPP film 20, and the C
A unique beautiful appearance can be formed only by mixing and coloring a pigment on any of the PP films 30.

As a printing method for forming the printing layer 4, the above-mentioned gravure printing is preferably employed, and any of various conventionally known printing methods which can use inks which can be printed on the respective surfaces are employed. It is possible. As the pigment to be kneaded into each layer, any of various pigments having excellent compatibility and dispersibility with the polypropylene resin can be used. (Laminated Foam) The laminated foam of the present invention is formed by laminating the CPP film 30 via the OPP film 20 on one or both sides of the polypropylene-based resin foam sheet 10 as described above. Further, the printing layer 4 may be formed on any interface of each layer as needed.

The laminated foam of the present invention basically includes the following 14 types of laminated structures (I) to (XIV) (actually, the OPP film 20 or the CPP film 3
A variation due to a laminated structure of 0 is added. However, since the description is complicated, the OPP film 20 and the CPP film 30 in the following classification include all those having such a laminated structure in addition to those having a single layer). (I) Three-layer structure of CPP film 30 / OPP film 20 / foam sheet 10.

(II) CPP film 30 / printing layer 3 / O
Four-layer structure of PP film 20 / foam sheet 10. (III) Four-layer structure of CPP film 30 / OPP film 20 / print layer 3 / foam sheet 10. (IV) Five-layer structure of CPP film 30 / print layer 3 / OPP film 20 / print layer 3 / foam sheet 10.

(V) CPP film 30 / OPP film 20 / foam sheet 10 / OPP film 20 / CPP
A five-layer structure of the film 30. (VI) Six-layer structure of CPP film 30 / print layer 3 / OPP film 20 / foam sheet 10 / OPP film 20 / CPP film 30. (VII) CPP film 30 / OPP film 20 / print layer 3 / foam sheet 10 / OPP film 20 / CPP
A six-layer structure of the film 30.

(VIII) CPP film 30 / printing layer 3 /
OPP film 20 / printing layer 3 / foam sheet 10 / OP
7 layer structure of P film 20 / CPP film 30. (IX) CPP film 30 / print layer 3 / OPP film 20 / foam sheet 10 / OPP film 20 / print layer 3
/ 7-layer structure of CPP film 30. (X) CPP film 30 / OPP film 20 / print layer 3 / foam sheet 10 / print layer 3 / OPP film 20
/ 7-layer structure of CPP film 30.

(XI) CPP film 30 / printing layer 3 / O
PP film 20 / foam sheet 10 / print layer 3 / OPP
7-layer structure of film 20 / CPP film 30. (XII) CPP film 30 / print layer 3 / OPP film 20 / print layer 3 / foam sheet 10 / OPP film 2
Eight-layer structure of 0 / printing layer 3 / CPP film 30. (XIII) CPP film 30 / print layer 3 / OPP film 20 / print layer 3 / foam sheet 10 / print layer 3 / OPP
Eight-layer structure of film 20 / CPP film 30.

(XIV) CPP film 30 / printing layer 3 /
A nine-layer structure of OPP film 20 / print layer 3 / foam sheet 10 / print layer 3 / OPP film 20 / print layer 3 / CPP film 30. (Method for Producing Laminated Foam) As a method for producing the laminated foam of the present invention by laminating the above layers, the thermal lamination method is suitably employed as described above.

For example, in the case of continuously producing a laminated foam in which the CPP film 30 is laminated on one side of the foam sheet 10 via the OPP film 20 as described in the above (I) to (IV), The sequential lamination shown in FIG.
Any of the simultaneous laminations shown in (b) can be employed. Among these, in the thermal lamination method by sequential lamination of FIG. 3A, lamination is performed in the following procedure.

First, a long foamed sheet 10, which has been manufactured by extrusion foaming in advance and wound into a roll, is fed from the roll 10a at a constant speed. Then, the surface temperature of the foam sheet 10 is set to 50 to 50 through the preheater H1.
After preheating to 90 ° C., it is supplied to a first roller pair R1 composed of a heating roller R1a and a nip roller R1b. Also, this is also manufactured by extrusion molding in advance,
The long OPP film 20 wound in a roll shape is fed out from the roll 20a at a constant speed in a state where the printing layer 4 is applied on one side or both sides as necessary. Then, it is supplied to the first roller pair R1 via the guide roller GR1, and is continuously heated and pressed while being laminated on one surface of the foamed sheet 10 for lamination.

The preferred conditions for lamination by the first roller pair R 1 are the foam sheet 10 and the OPP film 20.
, A heating temperature of the heating roller R1a of 180 to 210 ° C., and a nip pressure of the nip roller R1b of 4 to 10 kg / cm ² . Next, while feeding the above-mentioned laminate at a constant speed, the laminate is supplied to a second roller pair R2 including a heating roller R2a and a nip roller R2b.

Further, this is also extruded in advance and then manufactured by biaxial stretching, and if necessary, a printed layer 4
, A long CP wound into a roll
The P film 30 is unwound from the roll 30a at a constant speed. Then, the above-mentioned second through the guide roller GR2
To the roller pair R2, and the laminate of the foamed sheet 10 and the OPP film 20 is continuously heated and pressed while being laminated on the surface on the OPP film 20 side to perform lamination.

Then, as described above, the foam sheet 10
A long laminated foam in which the CPP film 30 is laminated on one side via the OPP film 20 is continuously manufactured. Suitable conditions for lamination by the second roller pair R2 are the same as described above. That is, the foam sheet 10, O
The passing speed of the PP film 20 and the CPP film 30 is 5 to 15 m / min, and the heating temperature of the heating roller R2a is 180.
~ 210 ° C, nip pressure of nip roller R2b 4 ~ 10
kg / cm ² .

On the other hand, in the thermal lamination method by simultaneous lamination of FIG. 3B, lamination is performed in the following procedure. That is, a long foam sheet 10 previously produced by extrusion foaming in the same manner as described above and wound into a roll shape.
At a constant speed from the roll 10a. Then, the foamed sheet 10 is first preheated through a preheater H1 so that the surface temperature of the foamed sheet 10 becomes 50 to 90 ° C., and then supplied to a roller pair R including a heating roller Ra and a nip roller Rb.

A long OPP film 2 as described above
0 and the CPP film 30 with each roll 20
a, 30a, and feeds out at a constant speed, and guide rollers GR
And supply it to the roller pair R. Then, the foam sheet 10, the OPP film 20, the CPP film 3
When laminated by heating and pressing continuously while overlapping in the order of 0, a long laminated foam body in which the above-described layers are laminated in this order is continuously produced.

Suitable conditions for lamination using the roller pair R are the same as described above. That is, the foam sheet 10, OP
The passing speed of the P film 20 and the CPP film 30 is 5 to 15 m / min, and the heating temperature of the heating roller Ra is 180 to 2
10 ° C., nip pressure of nip roller Rb 4 to 10 kg /
cm ² . Note that the foam sheet 10 is a sheet immediately after extrusion and foaming from an extruder directly connected to the apparatus of FIGS. (A) and (b), and is directly connected to the first roller pair R1 in the case of FIG. In the case of ()), it may be supplied to the roller pair R. In this case, since the foamed sheet 10 immediately after foaming has residual heat, the preheater H1 can be omitted. <Laminated foam molded article> From the laminated foam, as a thermoforming method for producing a laminated foam molded article of the present invention,
For example, various conventionally known molding methods such as vacuum molding, pressure molding, hot plate molding, or matched mold molding and plug assist molding as their applications can be employed.

The molded article of the present invention thus produced is
For example, as shown in an enlarged cross section in FIG. 1 (b), at least one side of the base layer 1 made of the foamed sheet 10 (one side in the figure, but also includes both sides as described later),
Through the intermediate layer 2 composed of the OPP film 20, the CPP
It has a surface layer 3 made of a film 30. And
Among them, the surface of the surface layer 3 has a calm texture that is appropriately matted by the synergistic action of the OPP film 20 and the CPP film 30 as described above. In addition, since this surface state appears almost uniformly over the entire surface layer 3, the laminated foam molded article has a unique and beautiful appearance which has never been seen before.

In particular, the printing layer 4 is provided at any one of the interfaces of the respective layers located between the foamed sheet 10 and the CPP film 30, or the foamed sheet 10 or the OPP film 20 is colored by kneading a pigment. In such a case, the molded product has a much better design. Moreover, the laminated foam molded article has heat resistance, oil resistance, since each of the layers 1 to 3 constituting the molded article is formed of a polypropylene resin.
It has excellent chemical resistance and is easy to recycle.

As in the case of the laminated foam, the surface condition of the surface layer 3 is determined by the specular glossiness of the surface (incident angle θ = 60 °),
It is defined by the center line average roughness Ra. The preferred range is the same as in the case of the laminated foam. That is, the specular gloss is preferably from 6 to 60. If the specular gloss is less than 6, the matte is too strong, and if the specular gloss is more than 60, the matte is insufficient and the gloss is too strong. May not be obtained. In consideration of further improvement in design, the specular gloss of the surface of the surface layer 3 is preferably 40 or less in the above range.

The center line average roughness Ra is preferably 4 μm or less. When the center line average roughness Ra exceeds 4 μm, there is a possibility that a calm texture cannot be obtained. In consideration of further improvement in design,
The center line average roughness Ra is preferably 3 μm within the above range.
It is preferred that: By the way, center line average roughness Ra
Is of course 0 μm. FIG. 1
(a) (b) is an example of the laminated foam molded article of the present invention,
The pasta container C is shown.

The pasta container C shown in the figure has a shallow rectangular container main body C1 and a flange C2 extending outward from the upper end opening thereof for fitting a lid (not shown). It is manufactured by thermoforming from the laminated foam of the invention. CPP
The surface layer 3 formed from the film 30 is provided on the inner surface of the container C in the example shown in the drawing, but may be provided on the outer surface depending on the use of the container. In addition, the aforementioned (V) to (XIV)
The surface layer 3 may be provided on both surfaces of the container C by using the laminated foam of the above.

[0072]

The present invention will be described below with reference to examples and comparative examples. In addition, each characteristic of the polypropylene resin used in each Example and the comparative example, the foamed sheet, the manufactured laminated foam, and the molded article was measured and evaluated by the following methods, respectively. <Melt Tension Measurement> The melt tension of the polypropylene resin was measured as follows using a measuring device [Capillograph PMD-C] manufactured by Toyo Seiki Seisaku-sho, Ltd.

First, the sample resin is melted by heating to 230 ° C.
With the piston extruded plastome
Nozzle of nozzle (2.095mm in diameter, 8mm in length)
The lowering speed of the piston at a constant speed of 10 mm / min.
And extruded into a string. Next, this string-like object is
Passes through a tension detection pulley located 35 cm below the chisel
Then, using a take-up roll, the take-up speed
About 66 m / min ^TwoGradually increased with the acceleration of
And rolled it up. And when the string breaks
With the tension detected by the tension detection pulley.
Thus, the melt tension of the sample resin was obtained.

<Measurement of Density of Foamed Sheet> The density of the foamed sheet was determined by measuring the weight and volume of the foamed sheet and calculating the weight (g) / volume (cm ³ ). <Evaluation of thermoformability of laminate foam> The thermoformability of the laminate foam was determined by plug-assist molding the laminate foam so that the surface on the CPP film 30 side was inside the container. Pasta container C [has the appearance shown in FIGS. 1 (a) and 1 (b), and is 195 mm long, 175 mm wide and 25 m high
m) were visually observed and evaluated according to the following three grades.

×: tearing or the like occurred, and it could not be formed into a predetermined shape. Poor thermoformability. Δ: Elongation during molding was poor, and a locally thin portion was formed. Somewhat poor thermoformability. ：: Good molded product with good elongation at the time of molding, uniform thickness and high dimensional accuracy was obtained. Good thermoformability.

<Measurement of Specular Gloss> The specular gloss of the laminated foam and the laminated foam molded article was measured by the following method.
That is, in the case of a laminated foam, of the long laminated foam continuously manufactured using the apparatus of FIG. 2 (a) or (b), M
At five locations in the D direction, samples cut out from five locations in the TD direction (total 25 locations) were used as samples.
Also, pasta containers as laminated foam molded products (Fig. 1 (a) (b))
In the case of, a sample cut out from the flat bottom surface C1a was used as a sample.

Then, a specular gloss measurement device (the above-mentioned gloss checker IG-330 manufactured by Horiba, Ltd.)
Is used, the specular gloss in the TD direction and the MD direction of the surface of the CPP film 30 and the surface layer 3 is measured under the condition of the incident angle θ = 60 °, and the average value of the measured values in both directions is determined
The specular gloss of the sample was taken. In the case of the laminated foam, the minimum value and the maximum value were recorded among the specular gloss values of the samples cut out from a plurality of places as described above, and the average value of the specular gloss values of all the samples was obtained. In the case of pasta containers, the minimum and maximum values of the specular gloss values of the samples taken from 10 containers arbitrarily extracted during continuous production using a long laminated foam are recorded. At the same time, the average value of the specular gloss of all the samples was determined.

<Measurement of Center Line Average Roughness Ra> The center line average roughness Ra of the laminated foam and the laminated foam molded article was measured by the following method. That is, as the samples, all the samples collected in the measurement of the specular glossiness were used. Then, using a surface roughness measuring instrument (also described above, Handy Surf E-35A manufactured by Tokyo Seimitsu Co., Ltd.), a cutoff value of 0.1 was used.
CPP film 3 under the conditions of 8 mm and measurement length of 4.0 mm
0 and the center line average roughness Ra of the surface of the surface layer 3 in the TD direction and the MD direction were obtained, and the average value of the measured values in both directions was defined as the center line average roughness Ra of the sample.

Then, data processing was performed in the same manner as in the case of the specular gloss, and the minimum value, maximum value and average value of the center line average roughness Ra of the laminated foam and the laminated foam molded article were obtained. <Evaluation of heat insulating property of molded article> 200 cc of hot water (98 ° C) was put into the pasta containers manufactured in each of the examples and comparative examples, heated in a microwave oven with an output of 500 W for 2 minutes, and then the containers immediately after the heating were bare-handed. From the state when it was taken out of the microwave oven, its heat insulation was evaluated according to the following criteria.

A: Could be taken out without any problem with almost no feeling of heat. Very good heat insulation. ：: It could be taken out without any problem, as it felt warm. Good heat insulation. Δ: Heat was felt and could not be held for a long time.
Somewhat poor insulation. X: It was hot and could not be taken out with bare hands. Poor insulation. In each of the following Examples and Comparative Examples, in order to produce a foamed sheet, the following resin A-1 belonging to the resin (A), and the following B-1 and B-2 belonging to the resin (B): One of the polypropylene-based resins PP1 to PP4 containing the resins in the proportions shown in Table 1 was selected and used. <Resin A-1> Propylene-ethylene block copolymer manufactured by Montell SDK Sunrise, trade name SD632.

Melt tension: 21.9 g Melt index (MI) value: 3 Density: 0.90 g / cm ³ <Resin B-1> A propylene homopolymer manufactured by Montel SDK Sunrise, trade name PM600A.

Melt tension: 0.8 g MI value: 7.5 Density: 0.90 g / cm ³ <Resin B-2> Propylene homopolymer manufactured by Montell SDK Sunrise, trade name PL500A.

Melt tension: 1.8 g MI value: 3.3 Density: 0.90 g / cm ³

[0084]

[Table 1]

As the OPP film, one of the following three films was selected and used. <OPP film O-1> An OPP film made of propylene homopolymer and having a melting point of 159.6 ° C. and a thickness of 20 μm [P-2161 manufactured by Toyobo Co., Ltd.]. <OPP film O-2> An OPP film made of a homopolymer of propylene and having a melting point of 159.6 ° C. and a thickness of 25 μm [P-2161 manufactured by Toyobo Co., Ltd.]. <OPP film O-3> Made of propylene-ethylene random copolymer, melting point 144.6 ° C, thickness 40 µm
OPP film [trade name SF-2 manufactured by Santox Corporation]
1].

As the CPP film, one of the following three films was selected and used. <CPP film C-1> A 20-μm-thick CPP film made of propylene homopolymer [P-1111 manufactured by Toyobo Co., Ltd.]. <CPP film C-2> A 25-μm-thick CPP film made of propylene homopolymer [P-1111 manufactured by Toyobo Co., Ltd.]. <CPP film C-3> A CPP film in which a single red printing layer is formed on one surface of the CPP film C-2.

Example 1 <Preparation of foamed sheet> 100 parts by weight of PP1 polypropylene resin in Table 1 and 0.3 part by weight of a cell regulator [Hydrocerol HK-70 manufactured by Boehringer Co., Ltd.] were dried. Blended. Next, this mixture was placed in a tandem extruder (having a diameter of 90 mm) having two extruders, a first and a second.
-Φ115 mm). Then, the supplied mixture is melted in a first extruder connected to a hopper,
While mixing, butane (isobutane / normal butane = 65/35) was injected as a blowing agent. The butane injection amount was 2.0 parts by weight per 100 parts by weight of the resin.

After the butane was injected, the melted and mixed mixture was continuously supplied from the first extruder to the second extruder. And after cooling uniformly in this second extruder,
The foam was continuously extruded into the atmosphere at a discharge rate of 120 kg / h from the cylindrical die having a diameter of 240 mm connected to the end of the second extruder while being extruded into a cylindrical shape. Next, the obtained cylindrical foam was cooled with water at 24 ° C.
Cooling was performed from the inside of the cylinder along a 72 mm mandrel, and air was blown from an air ring larger than the outer shape of the cylinder to cool from the outside of the cylinder. Then, after cooling, cut at two points on the circumference with a cutter to obtain a density of 0.25.
g / cm ^3, thickness 1.5 mm, to prepare a foam sheet of a long wide 1045Mm.

<Production of Laminated Foam> On one side of the foam sheet prepared above, a long OPP film O-1 having a width of 1040 mm and a long CPP film C having a width of 1040 mm were provided.
-1 was laminated and bonded by a thermal lamination method using the simultaneous lamination shown in FIG. 2 (b) to produce a long laminated foam. The conditions for lamination were as follows. Preheating temperature of foamed sheet by preheating heater H1 (surface temperature of foamed sheet): 65 ° C Heating temperature of heating roller Ra: 190 ° C Nip pressure of nip roller Rb: 6 kg / cm ² Feeding speed of each layer: 10 m / min Production of a product>
Plug-assist molding was performed so that the P film side was on the inner surface side of the container, thereby producing the pasta container as a laminated foam molded product. The set temperature of the heater during molding was 250 ° C.

Example 2 <Preparation of foamed sheet> The procedure of Example 1 was repeated except that the polypropylene resin of PP2 in Table 1 was used and the amount of butane was 1.8 g by weight per 100 parts by weight of the resin. Density 0.3 g / cm ³ , thickness 1.0 mm, width 104
A 5 mm long foam sheet was produced. <Production of Laminated Foam> A laminated foam was produced in the same manner as in Example 1 except that the foam sheet produced above was used.

<Production of Laminated Foam Molded Product> The laminated foam was subjected to plug-assist molding under the same conditions as in Example 1 so that the CPP film side was the inner surface side of the container. Was manufactured. Example 3 <Preparation of foamed sheet> The density was adjusted in the same manner as in Example 1 except that the polypropylene-based resin of PP3 in Table 1 was used, and the amount of butane was set to 1.8 parts by weight per 100 parts by weight of the resin. 0.33 g / cm ³ , thickness 1.0 mm, width 10
A 45 mm long foam sheet was produced.

<Production of Laminated Foam> On one side of the foamed sheet prepared above, a long OPP film O-1 having a width of 1040 mm and a long CPP film C having a width of 1040 mm were provided.
-3 was laminated and bonded by a thermal lamination method using simultaneous lamination shown in FIG. 2 (b) to produce a laminated foam. The lamination conditions were the same as in Example 1. The CPP film C-3 was laminated such that the printed layer on one side was located at the interface with the OPP film.

<Production of Laminated Foam Molded Product> The laminated foam was subjected to plug-assist molding under the same conditions as in Example 1 so that the CPP film side was the inner surface side of the container, and the pasta container as a molded product was obtained. Was manufactured. Example 4 A laminated foam was produced in the same manner as in Example 3 except that the OPP film O-2 was used, and the pasta container as a molded product was produced.

Example 5 <Production of Laminated Foam> On one surface of the same foamed sheet prepared in Example 3, a long OPP film O-3 having a width of 1040 mm and a long CPP film C having a width of 1040 mm were provided.
-3 was laminated and adhered by a thermal lamination method using the sequential lamination shown in FIG. 2 (a) to produce a laminated foam. The conditions for lamination were as follows. The CPP film C-3 was laminated such that the printed layer on one side was located at the interface with the OPP film.

Preheating temperature of foamed sheet by preheating heater H1 (surface temperature of foamed sheet): 75 ° C. Heating temperature of heating roller R1a: 190 ° C. Nip pressure of nip roller R1b: 6 kg / cm ² Heating temperature of heating roller R2a: 190 ° C. Nip pressure of nip roller R2b: 6 kg / cm ² Feeding speed of each layer: 13 m / min <Production of laminated foam molded article>
The pasta container as a molded product was manufactured by plug-assist molding under the same conditions as in Example 1 so that the P film side was on the inner surface side of the container.

Example 6 A laminated foam was produced in the same manner as in Example 3 except that the CPP film C-2 was used, and the pasta container as a molded product was produced. Example 7 <Preparation of foamed sheet> The density was determined in the same manner as in Example 1 except that the polypropylene resin of PP4 in Table 1 was used and the amount of butane was set to 1.4 parts by weight per 100 parts by weight of the resin. 0.46 g / cm ³ , thickness 0.9 mm, width 10
A 45 mm long foam sheet was produced.

<Production of Laminated Foam> A laminated foam was produced in the same manner as in Example 1 except that the foam sheet produced above was used. <Production of Laminated Foam Molded Product>
The pasta container as a molded product was manufactured by plug-assist molding under the same conditions as in Example 1 so that the P film side was on the inner surface side of the container.

Comparative Example 1 A laminated foam was produced in the same manner as in Example 6 except that the OPP film was omitted and the foamed sheet and the CPP film C-2 were directly laminated. A container was manufactured. Comparative Example 2 A laminated foam was produced in the same manner as in Example 4 except that the CPP film was omitted, and the pasta container as a molded product was produced.

Comparative Example 3 The lamination order of the OPP film and the CPP film was reversed,
A laminated foam was manufactured in the same manner as in Example 6 except that the OPP film was used as the surface layer, and the pasta container as a molded product was manufactured. The above results are summarized in Tables 2 to 4.

[0100]

[Table 2]

* Comparative Example 3 uses O as described in the text.
This is the reverse of the lamination order of the PP film and the CPP film.

[0102]

[Table 3]

[0103]

[Table 4]

Specular gloss and center line average roughness R in the table
From the results of a, Comparative Example 1 in which the OPP film was omitted was
It was found that both the laminated foam and the molded product were too matte, and the surface roughness was too large, so that a moderately matte and calm texture could not be obtained. Comparative Example 2 in which the CPP film was omitted, and OPP film and CPP
In Comparative Example 3 in which the film lamination order was reversed, it was found that both the laminated foam and the molded product had insufficient matting and were too glossy, so that a calm texture could not be obtained.

On the other hand, in all of Examples 1 to 7, both the laminated foam and the molded product were moderately and sufficiently matted.
It was confirmed to have a calm texture. It was also confirmed that the surface condition was substantially constant and small in variation at a plurality of locations on the long laminated foam and in a plurality of molded articles manufactured in large numbers. Also, from the results of the moldability, it was found that all of the laminated foams of Examples 1 to 7 had good moldability.

Further, from the results of the heat insulating properties, it was revealed that all of the molded products of Examples 1 to 6 had sufficient heat insulating properties. Further, from the results of Example 7, when the foamed sheet is formed only of the resin (B), a laminated foam having a small density and a high heat insulating property cannot be obtained, but a laminated foam having a medium density. It was also confirmed that a body could be formed.

[0107]

As described above in detail, according to the present invention, it has heat resistance, oil resistance, heat insulation and excellent rigidity at high temperatures which can be used for microwave cooking and the like, and its surface is excellent. The present invention can provide a laminated foam molded article of a polypropylene resin having a sufficiently matte, calm texture and an unprecedented beautiful appearance. Further, according to the present invention, it is possible to provide a laminated foam capable of stably producing the above-mentioned laminated foam molded article while maintaining a constant degree of matting on the surface.

Further, according to the present invention, it is possible to provide a manufacturing method capable of efficiently manufacturing the above-mentioned laminated foam.

[Brief description of the drawings]

FIG. 1 is a view showing a pasta container as an example of an embodiment of a laminated foam molded article of the present invention, wherein FIG. 1 (a) is a plan view and FIG. 1 (b) is a longitudinal sectional view.

FIGS. 2A and 2B are cross-sectional views each showing an example of a layer structure of the laminated foam of the present invention.

FIG. 3 is a view for explaining a step of manufacturing the laminated foam of the present invention by a thermal lamination method.
(a) is an explanatory diagram of a thermal laminating method by sequential laminating, and (b) is an explanatory diagram of a thermal laminating method by simultaneous laminating.

[Explanation of symbols]

C Pasta container (laminated foam molded product) 1 Base layer 2 Intermediate layer 3 Surface layer 10 Foam sheet 20 Biaxially stretched polypropylene resin film (OPP
Film) 30 Unstretched polypropylene resin film (CPP film)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Eiji Asada 7-488-1 Nanjing Shumachi, Nara City, Nara Prefecture B202 (72) Inventor Yasuo Imai 4-3-1-15 Wakabadai, Nara City, Nara Prefecture (72) Inventor Nishioka Taku 153-1 Kamitakino, Takino-cho, Kato-gun, Hyogo (72) Inventor Shizuo Sekiguchi 708-76, Kamikoyama, Ishibashi-cho, Shimotsuga-gun, Tochigi F term (reference) 4F100 AK07A AK07B AK07C BA03 BA04 BA07 BA10A BA10C CA01 DJ01A EH17A EJ02AEJ172 EJ38B EJ422 GB15 HB31D JA07A JJ03 JK15C JN21C YY00C

Claims (12)

[Claims] 1. A non-stretched polypropylene resin film surface layer is provided on at least one side of a base material layer formed of a polypropylene resin foam sheet via an intermediate layer of a biaxially stretched polypropylene resin film. Foamed molded product of polypropylene resin. 2. A laminate foam obtained by laminating a non-stretched polypropylene resin film on at least one surface of a foamed sheet of a polypropylene resin via a biaxially stretched polypropylene resin film, and formed by thermoforming. The laminated foam molded article according to the above. 3. The specular gloss of the surface of the surface layer (incident angle θ = 6)
0 °) is from 6 to 60. 4. A surface layer having a center line average roughness Ra of 4 μm.
m. The laminated foam molded article according to claim 1, which is not more than m. 5. The laminated foam molded article according to claim 1, wherein a printed layer is provided at any one of the interfaces of the respective layers located between the foamed sheet and the unstretched polypropylene resin film. 6. A laminated foam comprising a non-oriented polypropylene resin film laminated on at least one surface of a polypropylene resin foam sheet via a biaxially oriented polypropylene resin film. 7. The laminated foam according to claim 6, wherein the non-stretched polypropylene resin film has a specular gloss (incident angle θ = 60 °) of 6 to 60 on the surface. 8. The laminated foam according to claim 6, wherein the center line average roughness Ra of the surface of the unstretched polypropylene resin film is 4 μm or less. 9. The biaxially stretched polypropylene resin film has a thickness of 5 to 50 μm, the unstretched polypropylene resin film has a thickness of 5 to 80 μm, and the total thickness of both films is 20 to 120 μm. Laminated foam. 10. A foamed sheet comprising: (A) 10 to 50% by weight of a polypropylene resin having a free terminal long chain branch in a molecule and having a melt tension of 6 g or more and 40 g or less, and (B) a melt tension of 0.1 g. A polypropylene-based resin having a weight average molecular weight Mw and a number average molecular weight Mn of 3 to 8 and having a ratio Mw / Mn of 3 to 8 which is not less than 01 g and less than 6 g;
The laminated foam according to claim 6, which is formed by mixing with 50% by weight and extrusion foaming. 11. The laminated foam according to claim 6, wherein a printed layer is provided at any one of the interfaces of the respective layers located between the foamed sheet and the unstretched polypropylene resin film. 12. The method for producing a laminated foam according to any one of claims 6 to 11, wherein a foam sheet, a biaxially oriented polypropylene resin film, and a non-stretched polypropylene resin film prepared in advance are used. A method for producing a polypropylene-based resin laminated foam, wherein the laminate is directly laminated and adhered by a thermal lamination method.