JPH01278539A - Polypropylene based resin expanded sheet and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject low-density expanded sheet by feeding a polypropylene based resin, styrene based resin and specific styrene based elastomer at a specific ratio to an extruder, melt kneading the components, feeding a specified amount of a readily volatile foaming agent, mixing and expanding the components while heating under pressure. CONSTITUTION:The objective expanded sheet, obtained by feeding 50-90pts.wt. polypropylene based resin, 50-10pts.wt. styrene based resin and 0-20pts.wt. styrene based elastomer containing >=10wt.% olefinic component to an extruder, melt kneading the components, feeding a readily volatile foaming agent in an amount of 0.2-1mol based on 1kg mixed resins, mixing the components while heating (preferably at 230-250 deg.C) under pressure, cooling the mixture (preferably to 170-200 deg.C) and then discharging the resultant mixture through fine gaps into the open air and expanding the discharged mixture, having 0.1-0.5g/cc density and <=5mm thickness and capable of providing vessels excellent in heat, oil resistance and bending strength by hot molding.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a novel polypropylene foam sheet and a method for producing the same, and relates to a heat-insulating container and a method for sterilizing the foam sheet with steam by heating and press-shaping the foam sheet. The present invention relates to a foamed sheet I for manufacturing a molded article made of a polypropylene resin foam that can be used as a food container that can withstand heating in a microwave oven, and a method for manufacturing the same.

(Prior Art) In recent years, the appearance of food container materials with excellent heat resistance and heat insulation properties has been awaited.

It has been well known that foamed sheets 1 to 1 are made into food containers by vacuum forming, and these molded products are
Polystyrene resin, which has the advantages of excellent moldability and low cost, is widely used.

However, this foamed food container made of polystyrene resin has poor heat resistance and corrosion resistance, and when heated together with food in a microwave oven, it is greatly deformed and cannot be put to practical use. In order to solve this problem, the current situation is to maintain heat resistance by bonding a highly heat-resistant polyethylene film or polyester film to foamed sheets 1 to 1 made of polystyrene resin. However, laminating the heat-resistant film 11 on such a foamed sheet 1 not only complicates the production process and vacuum forming process of the foamed sheet 1~, but also sacrifices the price, which is the biggest advantage. turn into.

Therefore, in JP-A No. 62-94539, it was discovered that a foamed sheet 1 of heat-resistant polystyrene, a copolymer resin of 99 to 50% by weight of styrene and 1 to 50% by weight of methacrylic acid, was used as the resin. However, although the heat resistance is better than the +B polystyrene foam sheet 1~, the heat resistance and oil resistance of the foam sheet is still insufficient even if such heat-resistant polystyrene is used, so it is still necessary to attach a polypropylene or polyester film. There was a lot to match. In this case, it was also a problem to use an adhesive that was more expensive and had higher heat resistance. - On the other hand, there are also heat-resistant containers made of thermoformed polypropylene foam sheets on the market. However, polypropylene foam sheets 1~ have a density of at most 0, [i Iζ/(, However, it could not be used as a large container.

(Problems to be Solved) Therefore, the present inventor 19 conducted various tests to solve the above drawbacks (1) By mixing polypropylene and polystyrene, the characteristics of both, namely heat resistance and i1+
The present invention was completed by discovering a foamed sheet 1 which has a high density, does not get hot when held in the hand, has good bending strength, and can be used to laminate polypropylene fill 11 without using an adhesive. It is written.

(Means for Solving the Problem) That is, the present invention uses 50 to 90 parts by weight of polypropylene resin, 50 to 10 parts by weight of styrene resin, and 0 styrene elastomer containing 10% or more of an olefin component. ~20 parts by weight with a density of 0.1~0.
It is a polypropylene resin foam sheet for heat molding of 5 g/cc and a thickness of 5 mm or less, and the polystyrene resin contains 75 to 955 to 95 parts by weight of a styrene component containing at least one component of acrylic acid, methacrylic acid, and maleic anhydride. A styrene resin having a softening point of 115° C. or higher is preferable. In addition, as a method for producing the polypropylene resin foam sheet 1 for heat molding, 50 to 90 parts by weight of polypropylene resin, 50 to 10 parts by weight of styrene resin, and 10 or more parts of olefin component are added to an extruder. 1 to 20 parts by weight of styrenic elastomers are supplied in a proportion of 0 to 20 parts by weight, and once melted and kneaded in an extruder, a highly volatile blowing agent is added to the mixed resin at a rate of 1 kV from the middle of the extruder. A foamed polypropylene resin sheet for thermoforming, characterized in that it is supplied at a ratio of 0.2 to 1 mole, mixed under heating and pressure, then cooled to a resin temperature, and discharged into the atmosphere through slits to cause foaming. This is a manufacturing method.

Further, the present invention will be explained in detail in 9. That is, polypropylene (hereinafter sometimes abbreviated as circle) has excellent physical properties such as impact resistance, tensile strength, and bending resistance, but compared to polystyrene. In order to supplement this rigidity with polystyrene (hereinafter sometimes abbreviated as PS), various attempts have been made to melt-mix polystyrene with polypropylene. However, polypropylene and polystyrene have poor compatibility, and simply melt-mixing the two causes phase separation, making it impossible to obtain a resin composition with practical strength. However, according to research by the present inventors, polypropylene resin and polystyrene resin are supplied at a ratio of 60 to 90 parts by weight to 40 to 10 parts by weight, and after being melt-kneaded in the extruder, Add 0 easily volatile blowing agent to 1 kg of mixed resin from
．． It has been found that both resins are uniformly mixed when supplied at a ratio of 2 to 1 mole. Furthermore, the styrene resin used is a resin blended in a ratio of 50 to 90 parts by weight of a polypropylene resin to 50 to 90 parts by weight of heat-resistant polystyrene modified with one component of acrylic acid, methacrylic acid, or maleic anhydride. is fed to the extruder, heated and kneaded, and then further fed with resin 1. to the extruder. When the easily volatile foaming agent is supplied at a ratio of 0.1 to 1 mole to kV and kneaded under heat and pressure, the two types of resins are well mixed and a good foamed sheet I is produced.
The present invention was based on the discovery that the following can be obtained.

The polypropylene resin referred to in the present invention is a propylene homopolymer or a comonomer containing 5 mol% or less of monomer units, such as monomer units such as ethylene, ethyl acrylate, and ethyl methacrylate, or units from graph 1 of unsaturated carboxylic acid. Melt flow index (MFR) of polypropylene resin (JISK675) including propylene copolymer
As for 8), it is preferable to use a material of 5 or less because it foams well.In addition, from the viewpoint of the toughness of the foam sheet and the stiffness and heat resistance, it is preferable to use a propylene homopolymer and 5 mol%.
Preferably, the following comonomers are block polymerized. Furthermore, the polystyrene resin used in the present invention is polystyrene or acrylic acid having a normal gray level 1,
A heat-resistant polystyrene containing 75 to 90% by weight of a styrene component containing at least one component of methacrylic acid and maleic anhydride and having a softening point of 115°C or higher,
If the heat resistance is lower than 115"C, the heat resistance will deteriorate. Here, the softening point is JIS K
This is the softening point measured by 7206.

As mentioned above, the heat-resistant styrene resin is a styrene component containing at least one component of acrylic acid, methacrylic acid, or maleic anhydride, or 75 to 95% by weight of JP-A-57.
It is preferable to use the resin described in JP-72830, and among them, a copolymer with maleic anhydride is preferable from the viewpoint of foamability and physical properties.

Regarding the blending ratio of polypropylene resin and polystyrene resin, the higher the ratio of polypropylene resin, the better the heat resistance and oil resistance of foamed sheet 1 can be obtained, but the foamed sheet will have lower bending strength and higher density. Conversely, when the proportion of polystyrene resin increases, a sheet with low density and high stiffness can be obtained, but heat resistance and oil resistance decrease.

In order to improve the compatibility between stiff polypropylene and polystyrene resins, it is effective to use 0 to 20 parts by weight of a styrene elastomer containing 10% or more of an olefin component. Among them, after copolymerization of butadiene and styrene, hydrogen flow force 11 was applied to the double bond.
It is particularly effective to use 5 to 10 parts by weight. More preferably, the ex-1-mer is modified with 3% or less of acrylic acid or maleic anhydride.

If the density of the foam sheet is less than 0.14/cc, not only will the strength of the molded product be insufficient, but also holes may be formed in the molded product due to insufficient elongation during heating and vacuum molding. On the other hand, 0.
Above 5E/CC, there is an economical problem, but when you heat food in a container, it gets too hot to hold in your hands. A sheet with a thickness of 51 mm or more has open cells, resulting in poor thermoformability, and when used as a container, there is a problem in that moisture and oil seep into the sheet. This foamed sheet 1~ is an important feature of merino L- because it can be directly laminated with polypropylene having a thickness of 20 to 100 microns by heating without an adhesive in order to further improve heat resistance, oil resistance, elastic strength, etc.

A feature of the production method of the present invention is that polypropylene resin and polystyrene resin, which are originally considered to be immiscible, are thoroughly mixed. The first method is to melt and mix the polypropylene resin and the polystyrene resin in advance, supply a blowing agent thereto, and use the solvent effect to mix the mixture more uniformly. Therefore, it is necessary to use a blowing agent that is easily volatile, and the second characteristic is the amount used, which is 5 to 10 times higher than the amount corresponding to the desired expansion ratio. It is in the point of use.

Foaming agents include propane butane, pentane, dichlorodifluoromethane, dichlorotetrafluoroethane, carbon dioxide gas, etc., which are liquid under pressure at room temperature and evaporate by heating, or aliphatic materials with a boiling point of 150°C to 50°C. Alternatively, it is desirable to use halogenated aliphatic hydrocarbons.

The amount of blowing agent to be used is 0.2 to 1 mole per 1 kg of resin; if it is less than 0.2 mole, a good foam cannot be obtained due to insufficient crosstalk, and if it is less than 1.0 mole, a good foam cannot be obtained. -1;, the bubbles are broken and only sheets 1 to 1 with a rough surface are obtained.

Furthermore, the feature of this manufacturing method is that the resin and foaming agent are mixed at 230-2.
The process is carried out at 50°C and then cooled to 170-200°C to foam. That is, 30 to 80 degrees Celsius above the maximum mixing temperature.
, preferably at 30-50'C cooling, which is more gentle than the cooling done in other foam production. If kneaded at a high temperature, the melt viscosity of the polypropylene resin and polystyrene resin will increase, resulting in non-uniform mixing, and if the mixture is cooled too much, the flow of the polypropylene will deteriorate, making it impossible to obtain a good foam.

The cooled resin is discharged into the atmosphere from the slit-shaped mold, but it is preferable to use a ring-shaped slit, and the thickness of the slit is generally 0.2~ Use a 2mm one.

The present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example "Polypropylene resin (Jumin Chemical KK Norfren [?52
011D) 60 parts by weight and polystyrene resin (Kari Kasei KK
A mixture of 40 parts by weight of Styron 683) and finely powdered Tal 9 heavy weight part was supplied to an extruder.

Two extruders with a diameter of 50 mm and a diameter of 65 mm were used, and the I'' gold was 80 mm in diameter and 0.5 mm in thickness.
A material having an annular gap of mm was used.

The resin composition was heated and kneaded in a 50 mm extruder, and 0.5 mol of butane was injected into 1 kg of the resin composition adjusted to about 240° C., and then fed to an extruder with a diameter of 651 m1 to mix the resin. Adjust the temperature to 181℃ and heat at 25k for 1 hour.
The resin was extruded from the slit at a rate of F.

By pulling the extruded sheet 1 resin along a cooled cylinder with a diameter of 204 mm, the thickness was
], a sheet having a width of 55 mm, a width of 640 mm, and a density of 0.371 H/cc was wound up.

This sheet was molded into the container shape shown in Figure 1, and 150 cc of salad oil was poured into the molded container (container dimensions: length 156 mm x width, 26 mm x depth 30 mm), heated in a microwave oven, and the container was heated. Heat resistance and oil absorption into the container were measured.

The measurement method is a microwave oven (Sharp KK: R-9000
600111) and heated for 8 minutes until the temperature reached 140° C. The container was immediately removed from the microwave oven, and after removing the salad oil from the container, the shape and dimensional changes of the container were measured. The measurement points were measured at the depth part where dimensional changes are particularly large among length, width, and depth. As a result, a slight change in shape was observed, but no dimensional change was observed.

Also, the amount of oil absorbed into the container was about 3.2 g. Also, the elastic modulus of the sheet is 110 mm (measurement conditions and method are: bending speed: 50 mm/min, span interval: 30 mm, jig tip: 3.2 mm, test piece: original cloth wool x 50 mm x 15
0Lmm) was 5,730 kgf/cd in the flow direction and 5,580 kgf/ci in the width direction.

Example 2 65 parts by weight of polypropylene resin (Jumin Kagaku KK Noblen 115゜1), 30 parts by weight of polystyrene resin (Asahi Kasei KK Stylon 683), and 5 parts by weight of saturated thermoplastic elastomer resin (Amikasei KK Tufty' M1913). A mixture of 91 parts by weight of finely powdered tar was fed to an extruder.

Hereinafter, the same method as in Example] was carried out. That is, 50m
m extrusion machine jf The resin composition was heated and kneaded to about 240
0.5 mol of butane was injected into 1 kg of the resin composition adjusted to a temperature of The resin was extruded from the

The extruded resin has a thickness of 1.22 mm,
It had a width of 640 mm and a density of 0.46 g/cc.

As a result of measuring the heat resistance of the container and the amount of oil absorbed into the container, there was no change in shape or dimension. Also, the amount of oil absorbed into the container was about 2.7 g. Also, the bending elastic modulus of Sea I is 6,400 kgf/cn in the flow direction? , width direction is 6,4
It was 40kgf/CJK.

Example 3 Polypropylene resin (Jumin Chemical KK Noblen Fil1
015) 75 parts by weight, 20 parts by weight of polystyrene resin (Amikasei KK Styron 666), and saturated thermoplastic EX1
- A mixture of 5-type dish part of mer resin (Amikasei KK Toughtic Formerly 041) and 1 heavy-sized part of finely powdered talc was supplied to an extruder.

The following procedure was carried out in the same manner as in Example 1. That is, 50m
The resin composition was heated and kneaded in an extruder at about 240°C.
Butane was added to 1 kg of the resin composition adjusted to 0°3
8 mol was press-fitted and supplied to an extruder having a diameter of 65 nwn, and the resin temperature was adjusted to 90° C., and the resin was extruded through the slit at a rate of 22 kg for 1 hour. The extruded sheet-shaped railing has a thickness of 1.1.7 mm, a width of 640 mm, and a density of 0.43 g/cc.
Met.

As a result of determining the heat resistance of the container and the amount of oil absorbed into the container as dl, there was no change in shape or dimension. Also, the amount of oil absorbed into the container was about 0.8 g. The bending elastic modulus of the sheet is 7,870 kgf/c+fl in the flow direction and 6 in the width direction.
, 440 kgf/ci.

Example 4 Polypropylene resin (Jumin Chemical KK Noblen A115
85A) 80 parts by weight and impact-resistant polystyrene resin (New 1) Honsei Kagaku KK S-61) 15 heavy foot parts and saturated thermoplastic elastomer resin (/l!! Kasei KK Toughtic 111041) Type 5 A mixture of the nests and 1 part by weight of finely powdered talc was supplied to an extruder.

The following procedure was carried out in the same manner as in Example 1. That is, 50m
The resin composition was heated and kneaded using an extruder, and 0.33 kg of butane was added to 1 kg of the resin composition, which was adjusted to about 240°C.
molar press-in, then supplied to an extruder with a diameter of 65 mm,
Resin temperature reaches 187℃:! The resin was extruded from the slit at a rate of 22 kg for 1 hour. The extruded resin sheet has a thickness of 1.37 mm, a width of 640 mm, and a density of 0.49.
g/cc.

As a result of measuring the heat resistance of the container and the amount of oil absorbed into the container, there was no change in shape or dimension. Further, the amount of oil absorbed into the container was about 1.3 g. Also, the bending elastic modulus of the sheet is
7,250 kgf/cnT in the flow direction, 7,0 kgf/cnT in the width direction
It was 90 kgf/at.

Example 5 Polypropylene resin (Mitsubishi Yuka KK Noblen Rule 8)
A mixture of 70 parts by weight of polystyrene resin (additive KK Styron 666), 5 parts by weight of saturated thermoplastic nydistomer resin (Shell Chemical KK Kraton 1.657), and 1 part by weight of finely powdered talc was placed in an extruder. supplied.

The following procedure was carried out in the same manner as in Example 1. That is, the resin composition was heated and kneaded in a 50° old control machine, and heated to about 240°C.
0.43 mol of cyclodifluoromethane (Freon 12) was injected into 1 kg of the resin composition adjusted to
Supplied to an extruder with a diameter of 651III, the resin temperature was 181
The resin was extruded through the slit at a rate of 26 kg for 1 hour. The extruded resin has a thickness of 1.2
0 mm, width 640 mm, and density 0.35 g/cc.

As a result of measuring the heat resistance of the container and the amount of oil absorbed into the container, a change in shape was observed, but no dimensional change was observed. Also, the amount of oil absorbed into the container was about 2.8 g. Also, the elastic modulus of the sheet is 5,260 f/c in the machine direction.
d, width direction is 5,090 kgf/an? Met.

Example 6 A mixture of 70 parts by weight of polypropylene resin (homopolymer MFR2), 30 parts by weight of heat-resistant polystyrene resin (styrene maleic anhydride copolymer Vicat softening point 136°C), and 1 part by weight of talc was supplied to an extruder. . An extruder with a diameter of 50 mm and a diameter of 65 mm was used, and a die having an annular slit with a diameter of 80 mm and a thickness of 0.6 mm was used. The resin composition was heated and kneaded in an extruder with a diameter of 50 mm, and about 240 mm from the tip of a 50 mm EYT was heated.
0.43 mol of liquefied butane was injected into 1 kg of resin adjusted to °C, and then fed into an extruder with a diameter of 65 dishes.
The resin temperature was adjusted to 1908C and the resin was extruded through the slit at a rate of 25 kg for 1 hour.

By taking the extruded resin into a cooled cylinder with a diameter of 204 mm, the thickness], 1.
A sheet having a size of 4 mm, a width of 640 mm, and a density of 0.5 g/cc was wound up.

This sheet was molded into the container shape shown in FIG. 1, and the heat resistance of the container and the amount of oil absorbed into the container were measured. As a result, there was no change in shape or dimension. Also, the amount of oil absorbed into the container is approximately 2.5
It was g. In addition, the bending elastic modulus of the sheet (measurement conditions and method are bending speed: 50 mm/mjn, span interval: 3
0mm, jig tip: 3.2Rmm, test piece, original thickness t
X 5 (h X 150Lmm) is 7,91 in the flow direction
0 kgf/cJ, and the width direction was 6,040 kgf/c+4.

Example 7 Polypropylene resin (block copolymer MFR3) 6
A mixture of 5 parts by weight, 30 parts by weight of heat-resistant polystyrene resin (maleic anhydride copolymerized Bicart-136°C), 5 parts by weight of styrene elastomer resin (Water Source 5BS), and 1 part by weight of talc was supplied to the extruder. did. The same extruder as in Example 1 was used. The resin composition was heated and kneaded in an extruder with a diameter of 50 mm, and 0.52 mol of liquefied butane per 1 kg of resin was injected from the tip of a 50 mm EYT, and then fed into an extruder with a diameter of 65 m, and the resin temperature was increased to 1.
The temperature was adjusted to 85°C, and resin was extruded through the slit at a rate of 25 kg for 1 hour. Example 1
The thickness is 1.48mm and the width is 640mm.

Seams 1~ with a density of 0.48 g/cc were rolled up. The heat resistance of the container and the amount of oil absorbed into the container were measured using the same method as in Example 1, and as a result, there was no change in shape or dimension. Also, the amount of oil absorbed into the container was about 3 g.

The bending elastic modulus of the sheet was measured in the same manner as in Example 1. Flow direction is 3,040kgf/a#, width direction is 4,070kgf/a#
kgf/d.

Example 8 Polypropylene resin (homopolymer MFR2,5) 65
A mixture of 30 parts by weight of heat-resistant polystyrene resin (softening point] 36°C), 5 parts by weight of styrene-based nystomer resin (water 145Bs), and 1 part by weight of talc was mixed into an extruder. supplied.

The same extruder as in Example 1 was used. Diameter 50m
The resin composition was heated and kneaded in an extruder of 50 mm.
1 kg of resin adjusted to approximately 240'C from the tip of E YT
0.33 mol of liquefied dichlorodifluoromethane (Freon 12) was then fed into an extruder with a diameter of 65 mm, the resin temperature was adjusted to 190°C, and the resin was expelled from the slits at a rate of 25 kg per hour. Extruded. The extruded sheet-shaped resin was collected in the same manner as in Example 1 to a thickness of 1.33 mm.
A sheet with a width of 640 mm and a density of 0-47 g/cc was rolled up. To measure the heat resistance of the container and the amount of oil absorbed into the container,
As a result of carrying out the same method as in [Example], there was no change in shape or dimension. Further, the amount of oil absorbed into the container was about 2.5 g. The bending elastic modulus of the sheet was measured in the same manner as in Example 1. Flow direction is 4,430kgf/cnT, width direction is 4
, 280kgf/cnT.

Example 9 Polypropylene resin (homopolymer MFR2,5) 65
A mixture of 30 parts by weight of heat-resistant polystyrene resin (maleic anhydride copolymerization Vicat softening point 136°C), 5 parts by weight of styrene elas 1-mer resin (SIS) and 1 part by weight of talc is supplied to an extruder. did.

The same extruder as in Example 1 was used. Diameter 50m
The resin composition was heated and kneaded in an extruder of 50 mmE.
From the tip of the YT, 0.52 mol of butane per kg of the resin was adjusted to approximately 240°C was injected, the resin temperature was adjusted to 182°C, and the resin was extruded through the slit at a rate of 25 kg for 1 hour. The extruded resin in the form of a sheet 1 is taken up in the same manner as in Example 1 to a thickness of 1. ．． 40mm, width 640mm, density 0.
A sheet of 48 g/cc was rolled up. The heat resistance of the container and the amount of oil absorbed into the container were measured using the same method as in Example 1, and as a result, there was no change in shape or dimension. Further, the amount of oil absorbed into the container was about 1.0 g. The bending elastic modulus of the sheet was measured in the same manner as in Example 1. Flow direction is 6,57
0 kgf/cd, and 5,340 kgf/cJ in the width direction.

Example 10 70 parts by weight of polypropylene resin (homopolymer MFR2), 20 parts by weight of heat-resistant polystyrene resin (maleic anhydride copolymerized with a softening point of 1 to 133°C), and a large amount of styrene elastomer resin (hydrogenated 5BS) A mixture of 1 part by weight of talc and 1 part by weight of talc was supplied to an extruder.

The same extruder as in Example 1 was used. Diameter 50m
The resin composition was heated and kneaded in an extruder of 50 mm.
1k of resin adjusted to approximately 240℃ from the tip of IE YT
0.52 mol of butane per g was injected, and the resin temperature was 19.
The temperature was adjusted to 0° C., and resin was extruded through the slits at a rate of 22 kg for 1 hour. The extruded resin sheet 1 is taken off in the same manner as in Example 1 and is reduced to a thickness of 1. ], 5 mm in width, 640 mm in width, and a density of 0.45 g/cc. The heat resistance of the container and the amount of oil absorbed into the container were determined using the same method as in Example], and as a result, there was no change in shape or dimension. Further, the amount of oil absorbed into the container was about 0.5 g. The elastic modulus of the sheet was determined in the same manner as in Example 1. The flow direction was 4,920 kgf/afl, and the width direction was 3,650 kgf/cJ.

Example 11 Polypropylene resin (homopolymer MFR2,5)/1
5 parts by weight, 45 parts by weight of heat-resistant polystyrene resin (maleic anhydride coheavy metal Picat softening point 136°C), 10 parts by weight of styrene elastomer resin (hydrogenated 5BS), and Tal 91
The mixed parts by weight were fed into an extruder.

The same extruder as in Example 1 was used. Diameter 50m
The resin composition was heated and kneaded in an extruder of 50mmt.
From the tip of the EYT, 0.45 mol of carbon dioxide (CO, ) was injected per kg of resin adjusted to about 240°C, the resin temperature was adjusted to 180°C, and the resin was poured from the pores at a rate of 27 kg for 1 hour. Extruded. The extruded resin sheet was taken out in the same manner as in Example J to a thickness of 1.23 mm and a width of 640 m.
A sheet with a density of 0.35 g/cc was wound up. The heat resistance of the container and the amount of oil absorbed into the container were measured using the same method as in Example 1, and as a result, there was no dimensional change except for a slight change in shape. Further, the amount of oil absorbed into the container was about 1.2 g. The bending elastic modulus of the sheet is as shown in Example 1.
I did it the same way. Flow direction is 4,470kgf/a
(The width direction was 3,490 kgf/a#.

Example 12 60 parts by weight of polypropylene resin (homopolymer MFR2) and transparent, heat-resistant resin (styrene, methyl methacrylate-1)
A mixture of 30 parts by weight of 1-copolymer resin), 10 parts by weight of styrene-based elastomer resin (hydrogenated 5BS), and 1 part by weight of talc was supplied to an extruder.

The same extruder as in Example 1 was used. Diameter 50m
The resin composition was heated and kneaded in an extruder of 50 mm.
1k of resin adjusted to about 240℃ from the tip of E
Pressurely inject 0.6 mol of liquefied butane per g, resin temperature] 8
The temperature was adjusted to 2°C and the resin was extruded through the slit at a rate of 25kHz for 1 hour. The extruded sheet-shaped resin was taken up in the same manner as in Example 1, and sheets 1 to 1 with a thickness of 64 mm, a width of 640 mm, and a density of 0.40 g/cc were rolled up. The heat resistance of the container and the amount of oil absorbed into the container were determined in the same manner as in Example 1, and as a result, there was no change in shape or dimension.

Also, the amount of oil absorbed into the container is approximately 2. It was yesterday. sea 1
The bending elastic modulus was determined in the same manner as in Example 1. The flow direction is "I", 330kgf/aK, the width direction is 3,
It was 880kgf/tome.

As described above, a CP film having a thickness of 30 to 70 microns was pressed onto the foamed sheet I obtained in Examples 1 to 2 while contacting it with a Teflon kneaded heated roll at about 180'C. This laminated sheet laminated with a foam sheet was molded so that the CPP film was on the inner surface of the container, and the test 1 of heat resistance and oil absorption was conducted in the same manner.As a result, the heat resistance improved only slightly. However, the oil absorption amount was mostly O.

Comparative Example 1 Polystyrene resin (Asahi Kasei KK Styron 683) 10
0 parts by weight and 1 part by weight of finely powdered talc were fed into the extruder.

The following procedure was carried out in the same manner as in Example 1.

The resin composition was heated and kneaded in a 50 mm extruder, and 0.8 mol of butane was injected into L kg of resin adjusted to about 230°C from the tip thereof, and then fed to a 65+nn+ extruder, and the resin temperature was 178°C. 27k for 1 hour adjusted to °C
The resin was extruded through the slit at a rate of g.

The extruded resin has a thickness of 1. ．． 85mm,
It had a width of 640 mm and a density of 0.25 g/cc.

As a result of determining the heat resistance of the container and the amount of oil adsorbed to the container as dl, the change in shape was 1.0 m and the change in size was 1.0 m.
m deformed. Also, the amount of oil absorbed into the container was about 11 g. The bending elastic modulus of the sheet is 1,580 in the machine direction.
kgf,/cot, width direction is 1. , 240kgf/
It was ci.

Comparative Example 2 Polypropylene resin (Jumin Chemical KK Noblen FS20
1.1) 25 parts by weight, 70 parts by weight of polystyrene resin (Asahi Kasei KK Stylon 683), and saturated thermoplastic elastomer resin (Okasei KK Toughtic 111.041) 5
A mixture of parts by weight and 1 part by weight of finely powdered talc was fed to an extruder.

The following procedure was carried out in the same manner as in Example 1. The resin composition was heated and kneaded in a 50 mm extruder, and about 235 mm
0.5 mol of butane was injected into 1 kg of resin adjusted to °C, then fed to an extruder with a volume of 65 wn, and the resin temperature was 1 kg.
The temperature was adjusted to 80°C, and resin was extruded through the slit at a rate of 25 kg for 1 hour.

The extruded sheet 1 resin had a thickness of 1.45 mm, a width of 640 mm, and a density of 0.37 g/cc.

As a result of measuring the heat resistance of the container and the amount of oil absorbed into the container, there was a change in shape, and the dimensional change was 7 mm. Also, the amount of oil absorbed into the container is approximately ], ], 5. ．． There was. The bending elastic modulus of the sheet is 3,470 kgf/c in the machine direction.
rM, width direction was 2,850 kg:[/aA.

Comparative Example 3 Polypropylene resin (Jumin Chemical KK No Blend '52
0110) A mixture of 100 parts by weight and 1 part by weight of finely powdered talc was supplied to an extruder.

The following procedure was carried out in the same manner as in Example 1. The resin composition was heated and kneaded in a 50 mm extruder, and about 2
Butane was added to 1 kF of resin adjusted to 40°C.
32 mol of the resin was injected under pressure, and then fed to a 65-barrel extruder, the resin temperature was adjusted to 185°C, and the resin was extruded through the slit at a rate of 22 kg for 1 hour. The extruded Sea 1-shaped resin is
Thickness 1.72mm, width 640mm, density 0.5g/cc
Met.

As a result of measuring the heat resistance of the container and the amount of oil absorbed into the container, there was no change in shape or size. In addition, the oil absorption base of the oil content in the container was approximately 1.3 F3, and the bending elastic modulus in the sea 1 was 9,700 kgf/a+f in the flow direction and 3.57Ql<gf/co? in the width direction. Met. Furthermore, when this sheet was molded into the container mold shown in FIG. 1, it sagged during preheating and the mold did not come out well.

Comparative Example 4 22 parts by weight of polypropylene resin (homopolymer old ?R2), 68 parts by weight of heat-resistant polystyrene resin (styrene, maleic anhydride copolymerized with a softening point of 1 to 133°C), and styrene elastomer resin (hydrogenated 5BS) A mixture of 10 parts by weight and 1 part by weight of talc was fed to an extruder.

The extruder used in Example 1 was used as an extruder. The resin composition was heated and kneaded in a 50 mm extruder to form a 50 mm
Resin adjusted to approximately 230℃ from the tip of IE X゛F],
0.86 mol of butane was injected per kg, and then,
The resin was fed into a 65 mm extruder, the resin temperature was adjusted to 180°C, and the resin was extruded through the slit at a rate of 26 kFy for 1 hour. The extruded sheet was pulled out in the same way as the extruded sheet [example of resin resin]. Thickness: 1.38 mm + Width: 540 mm + Density: 0
．． A sheet of 291X/cc was rolled up. The heat resistance of the container and the oil-absorbing groups in the oil content of the container were measured using the same method as in Example 1. As a result, there was a change in shape, and the change in =j''/A was 7 m.
It was m. Also, the amount of oil absorbed per minute of /li into the container is approximately 12
It was 1. The bending elastic modulus for sea 1 was determined in the same manner as for actual flow side 1. The flow direction was 3,650 kg1'/d, and the width direction was 2.720 kgf/cil.

Comparative Example 5 100 parts by weight of polypropylene resin (homopolymer MFR2), 91 parts by weight of Tal, and die blow No. 1 as a foaming agent.
2 (Dainichiseika, K)] was mixed and supplied to an extruder.

The extruder used was one with a diameter of 65 mm, and the extruder used was one having an annular slit with a diameter of 105 mm and a thickness of 0.65 mm. Adjust the resin temperature to 175℃ and
The resin was extruded through the slit at a rate of 20 kg/hr.

By pulling the extruded sheet-shaped resin along a cooled cylinder with a diameter of 220 mm, the thickness was reduced to 47 mm.
A sheet with a width of 690 mm and a density of 0.59 g/cc was wound up. The heat resistance of the container and the amount of oil absorbed into the container were measured using the same method as in Example 1, and as a result, there was no change in shape or dimension. Also, the amount of oil absorbed into the container was approximately 1.5 g. The flexural modulus of C.I. was measured in the same manner as in Example 1. The flow direction is 10,700k (Hf/C
ll1, width direction: 9, 1.50 kgf/ell.

=28-Furthermore, when this sheet was molded into the container shape shown in the 11th round, it sagged during preheating and the mold did not come out well.

Comparative Example 6 Transparent, heat-resistant resin (styrene, methyl methacrylate-1~
A mixture of 100 parts by weight of copolymer resin) and 1.5 parts by weight of talc was supplied to an extruder.

An extruder with a diameter of 90 mm and a diameter opening of 5 mm was used, and the die was 1.40 mm in diameter and 0.65 m in thickness.
A material having an annular slit of m was used.

The resin composition was heated and kneaded in an extruder with a diameter of 90 m.
0.86 mol of liquefied butane was injected into 1 kg of resin adjusted to approximately 2/IO'C from the tip of mm1EXT, and then supplied to a 1.15 mm diameter extruder, and the resin temperature was 18
The resin was extruded through the slit at a rate of 80 k , adjusted to 0 °C].

The extruded sea I-shaped resin was taken along a cylinder with an outer diameter of 640 mm, and the thickness was 2.16 mm, width], 000 mm.
+ The material was rolled up into Sea 1 with a density of 0 and 19 g/cc. The heat resistance of the container and the oil absorption (h) of the container were measured using the same method as in Example]. As a result, the large shape change and dimensional change were 9 mm. Transformation (Table-
1) was deformed by 9mm. Also, the amount of oil absorbed into the container was about 15 g. The bending elastic modulus of the sheet was measured in the same manner as in Example 1. Flow force: 1,710, -f/cn
? The width direction was 1.80 kgf/a.

The above results are shown in Table 1.

(Effects) As described above, the present invention is to obtain a foamed polypropylene sheet having a lower density and heat resistance than a resin composition in which a polystyrene resin is uniformly mixed with a polypropylene resin, and this foamed sheet can be used as a material. By vacuum forming the food container, it is possible to provide a container with heat resistance, oil resistance, and bending strength.

[Brief explanation of the drawing]

Figure 1 shows the foamed sheet 1 of the present invention used in the examples of the present invention.
FIG. 2 is a plan view of a container made up of two parts, and FIG. 2 is a partially sectional side view of the container. Applicant Sekisui Plastics Co., Ltd. Agent Patent Attorney BJ Naka Hiroshi Procedural Amendment (spontaneous) June 77, 1985 Director General of the Patent Office Yoshi 1) Moon Yi 1, Indication of Case 1988 Patent Application No. ”, 07525 No. 2, Name of the invention Polypropylene resin foamed seams 1 to 3 and its manufacturing method 3, Relationship with the case of the person making the amendment Patent applicant address 25-chome, Nankin-suumachi, Nara City, Nara Prefecture Name (2)
44) Sekisui Plastics Co., Ltd. Representative Mitsugu Kawamoto 4, Agent 105 Address 5th floor, New Toranomon Building, 2-5-5 Toranomon, Minato-ku, Tokyo (Telephone 03-501-1830) 7, Contents of amendment 1 , in the second line of page 14 of the specification, after "hereinafter," insert "except for changing the blowing agent". 2. Correct "0.5 mol of butane" in lines 4 and 5 on page 14 of the specification to "0.4 mol of dichlorodifluoromethane." 3. r6,440kgf/ci on page 15, line 13 of the specification
J is corrected to r7,430kgf/cntJ. (hereinafter ``2'')

Claims (1)

[Scope of Claims] 1. 50 to 90 parts by weight of polypropylene resin, 50 to 10 parts by weight of styrene resin, and 10 parts by weight of olefin component.
A foamed polypropylene resin sheet for heat molding having a density of 0.1 to 0.5 g/cc and a thickness of 5 mm or less, comprising 0 to 20 parts by weight of a styrene elastomer containing % or more. 2 Polystyrene resin is acrylic acid, methacrylic acid,
2. The polypropylene resin foam sheet for heat molding according to claim 1, wherein the styrene component containing at least one component of maleic anhydride is 75 to 95% by weight and is a styrene resin having a Vicat softening point of 115° C. or higher. 3. In an extruder, 50 to 90 parts by weight of polypropylene resin, 50 to 10 parts by weight of styrene resin, and 0 to 10% of styrene elastomer containing 10% or more of olefin component are added.
20 parts by weight of the foaming agent was supplied, and the mixture was once melted and kneaded in the extruder, and then from the middle of the extruder, the easily volatile foaming agent was supplied at a ratio of 0.2 to 1 mole per 1 kg of mixed resin, and the foaming agent was heated under pressure. A method for producing a polypropylene resin foam sheet for heat molding, which comprises mixing, cooling the resin, and ejecting the resin into the atmosphere through slits for foaming.