JPH11228720A - Resin foam, laminated foam and foam molded article using these - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel resin foam, a laminated foam, and a foam, which can be manufactured at a lower cost, such as a food container having excellent heat resistance, heat insulation, oil resistance, and impact resistance. And a foam molded article used. SOLUTION: The resin foam is a single occlusion type dispersed particle shape in which (a) a rubbery polymer containing a single continuous phase made of a styrene-based resin is dispersed in a continuous phase of a styrene-based resin. And, a unsaturated carboxylic acid, an unsaturated carboxylic acid ester or vinyl acetate, and a rubber-modified styrene resin containing a copolymer of ethylene and (b) a propylene resin in a weight ratio of ( a) / (b) = 50/50
The resin composition containing at a rate of ~ 95/5 was foamed.
In the laminated foam, a non-foamed resin layer was laminated on one or both sides of the resin foam. As the foamed molded article, the above-mentioned resin foam and laminated foam were thermoformed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a tray,
The present invention relates to a resin foam and a laminated foam used for food containers such as bowls and cups, a heat insulating material, a cushioning material, and the like, and a foam molded product using these.

[0002]

2. Description of the Related Art For example, food containers such as trays, bowls, cups, etc., which are sold in a supermarket or the like in which food is stored, are conventionally formed by foaming a styrene homopolymer foam sheet by vacuum molding or the like. Thermoformed ones were the mainstream. However, in recent years, with the spread of microwave ovens to general households and the increase in convenience stores, for example, there has been an increase in the opportunity to heat-cook foods that have been cooked in advance up to the stage before heating in a microwave for each container. Since the conventional food containers have insufficient heat resistance, there has been a demand for an alternative container which has excellent heat resistance and does not deform even when cooked.

[0003]

In order to meet this demand, non-foamed polypropylene containers were first examined. However, these containers did not have sufficient heat insulating properties, and for example, the food was transferred to ceramic tableware. As in the case of cooking by heating, the heat of the cooked food also causes the container itself to become hot, causing problems such as being unable to be taken out of the microwave with bare hands. It was not suitable for food containers as described above.

[0004] Then, styrene, (meth) acrylic acid, (meth) acrylic acid ester, and the like are used as materials for food containers which are excellent in heat resistance to cooking by microwave oven or the like and also excellent in heat insulation. A foam mainly comprising a copolymer with maleic anhydride or the like has been proposed (for example, Japanese Patent Application Laid-Open No. 3-109441, Japanese Patent Publication No. 4-555).
No. 86).

However, these foams have insufficient oil resistance. The impact resistance of the copolymer alone was insufficient. Therefore, in these prior arts, especially in order to improve the impact resistance, a copolymer containing a diene monomer or a component such as high impact polystyrene is blended into the foam, or the impact resistance and oil resistance are improved. In order to improve both, it is disclosed that a non-foamed resin layer is laminated on one or both sides of a foam formed in a sheet shape, but none of these measures can be said to be a sufficient measure. .

[0006] Foamed sheets based on the finding that blending a styrene-based resin with a propylene-based resin having excellent oil resistance not only improves oil resistance but also improves impact resistance have been proposed (for example, Japanese Unexamined Patent Publication (Kokai) No. Heisei (KOKAI)). JP-A-4-258645, JP-A-6-49261, etc.). However, since the styrene-based resin and the propylene-based resin are inherently poorly compatible, it is difficult to foam a simple mixture of the two, and a foam having a high expansion ratio, that is, a foam having excellent heat insulating properties, is required. There was also the possibility that the impact resistance was greatly reduced because of the non-uniform dispersion state.

In these prior arts, a special polypropylene having a syndiotactic structure is used as the propylene resin, or a styrene-isoprene block copolymer is compounded as the third component. Although the compatibility between the two resins is improved, there is a problem that the cost is too high to use a foam sheet employing any of these methods as a material for a highly versatile food container or the like.

[0008] An object of the present invention is to provide a novel resin foam, a laminated foam, and a foam, which are capable of producing a food container having excellent heat resistance, heat insulation, oil resistance and impact resistance at a lower cost. And a foam molded article using the same.

[0009]

Means for Solving the Problems In order to solve the above problems,
The inventors have studied variously the styrene resin used in the combined system of the styrene resin and the propylene resin.
As a result, even though it is one kind of high impact polystyrene, it has higher impact resistance than the conventional one,
Including a single continuous phase of styrene resin in a continuous phase of styrene resin, which has high impact resistance comparable to BS and is expected to be sufficiently competitive with ABS in terms of cost. Having a dispersed particle shape of a single occlusion (including inclusion) type in which a rubber-like polymer is dispersed, and at least one selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic esters and vinyl acetate. It has been clarified that the rubber-modified styrene resin containing a copolymer with ethylene has excellent compatibility with the propylene resin.

When such a rubber-modified styrenic resin is used together with a propylene-based resin at a predetermined compounding ratio, food containers and the like having excellent heat resistance, heat insulation, oil resistance and impact resistance can be manufactured at lower cost. The present inventors have found that a resin foam can be obtained, and have completed the present invention. Therefore, the resin foam of the present invention is (a) a continuous phase composed of a styrene-based resin, a rubber-like polymer containing a single continuous phase composed of a styrene-based resin is dispersed, dispersed particles of a single occlusion type A rubber-modified styrenic resin having a shape and containing a copolymer of at least one selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid esters and vinyl acetate with ethylene; (b) propylene (A) / (b) = 50 / 50-
It is characterized in that a resin composition containing 95/5 is foamed.

The laminated foam of the present invention is characterized in that a non-foamed resin layer is laminated on at least one surface of the above-mentioned resin foam formed in a sheet shape.
Furthermore, the foamed molded article of the present invention is characterized in that any one of the above-mentioned foamed articles is thermoformed into a predetermined shape.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below. As described above, the resin foam of the present invention has a single occlusion in which (a) a rubber-like polymer containing a single continuous phase made of a styrene-based resin is dispersed in a continuous phase made of a styrene-based resin. And a rubber-modified styrene resin containing a copolymer of ethylene and at least one selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic esters and vinyl acetate, (b) Propylene resin and (a) / (b) = 50/50 by weight ratio
It is obtained by foaming a resin composition containing at a ratio of about 95/5.

As the styrenic resin constituting the rubber-modified styrenic resin (a), not only a homopolymer of styrene but also a copolymer of styrene with another vinyl monomer can be used. Examples of other vinyl monomers copolymerizable with styrene include acronitrile, methacrylonitrile, acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, and the like. These styrenic resins may be used alone or in combination of two or more.

The rubbery polymer dispersed in the styrene resin is particularly preferably a diene rubber in consideration of the effect of imparting impact resistance to the foam, such as a diene rubber. Examples include polybutadiene, styrene-butadiene copolymer, and ethylene-propylene-non-conjugated diene terpolymer. As the polybutadiene, any of various polybutadienes from high cis polybutadiene having a high cis bond content to low cis polybutadiene having a low cis bond content can be used.

These rubbers can be used alone or in combination of two or more. The rubbery polymer is dispersed in a continuous phase made of a styrene resin so as to have a single occlusion type dispersed particle shape.
The single occlusion type dispersed particle shape means that a large number of rubber-like polymer particles dispersed in a continuous phase of a styrene-based resin Containing a single continuous phase consisting of
It has a so-called core-shell structure.

Such a single occlusion type dispersed particle shape is used in many ordinary rubber-modified styrene resins.
What is called a salami structure in which a large number of small particles of a styrene-based resin are included inside particles having a rubber-like polymer as an outer shell, as shown by particles of a rubber-like polymer dispersed in a continuous phase of a styrene-based resin. Apparently different. The rubber-modified styrenic resin having the above-mentioned single occlusion type dispersed particle shape has an advantage that appearance such as gloss is improved as compared with a resin having a salami structure.

The rubber-modified styrenic resin having a single occlusion type dispersed particle shape is obtained by, for example, polymerizing styrene in the presence of a block copolymer of styrene and a rubber component (such as a styrene-butadiene block copolymer). And so on. In the single occlusion type dispersion particle shape, the dispersion particle size of the rubber-like polymer particles in the continuous phase of the styrene resin is approximately 0.1 to 0.5 μm.
It is preferred to be on the order of magnitude.

If the dispersion particle size of the rubber-like polymer particles is less than the above range, the impact resistance of the foam may be reduced. Conversely, when the dispersed particle size exceeds the above range, the uniformity of the rubber-modified styrene resin is reduced, so that the impact resistance of the foam may also be reduced, and gloss and the like may be reduced. The appearance may be deteriorated. The dispersed particle size of the rubber-like polymer particles is preferably in the above range, particularly preferably about 0.2 to 0.4 μm.

The dispersed particle shape and the dispersed particle size of the rubber-like polymer particles are observed as follows. That is, an ultra-thin section of a rubber-modified styrenic resin was prepared using an ultramicrotome, etc., immersed in an osmium tetrachloride solution for about one day, stained, and then taken with a transmission electron microscope photograph. The dispersed particle shape of the rubber-like polymer particles is confirmed, and the dispersed particle size of the rubber-like polymer particles is measured.

The copolymer of ethylene and at least one selected from the group consisting of unsaturated carboxylic acids, unsaturated carboxylic acid esters and vinyl acetate to be contained in the rubber-modified styrenic resin is, for example, ethylene-ethylene copolymer. Acrylic acid copolymer, ethylene-methacrylic acid copolymer,
Examples include an ethylene-methyl methacrylate copolymer, an ethylene-ethyl methacrylate copolymer, an ethylene-ethyl acrylate copolymer, an ethylene-methyl acrylate copolymer, and an ethylene-vinyl acetate copolymer.
These copolymers can be used alone or in combination of two or more.

The copolymer is preferably contained in an amount of about 0.1 to 10 parts by weight based on 100 parts by weight of the rubber-modified styrenic resin. If the content of the copolymer is less than the above range, the impact resistance of the foam may be reduced. Conversely, when the content of the copolymer exceeds the above range, the heat resistance of the foam may be reduced.

The content of the copolymer is preferably in the above range, and particularly preferably about 1 to 5 parts by weight based on 100 parts by weight of the rubber-modified styrene resin. (A) above
Examples of the rubber-modified styrene resin described in
Various resins disclosed in JP-A-151500. Specific examples thereof include, but are not limited to, Sumibright DJ series (trade name, manufactured by Sumitomo Chemical Co., Ltd.).
0, DJ9000 and the like are preferably used because they are particularly excellent in oil resistance.

As the propylene resin (b) used in combination with the rubber-modified styrene resin (a), a random or block copolymer of propylene and ethylene can be used in addition to a propylene homopolymer. These propylene-based resins may be used alone or in combination of two or more. Note that propylene homopolymer,
That is, as the propylene portion in the polypropylene or the block copolymer of propylene and ethylene, any having various stereoregularities can be used, but in the present invention, the rubber-modified styrene of (a) is used. Because the resin itself has excellent compatibility with the propylene resin as described above, there is no need to use special and expensive special polypropylene having a syndiotactic structure, and it is mainly used for isotactic and atactic structures. (Of course, a small amount of a syndiotactic component may be contained), and a general-purpose general-purpose polypropylene can be used.

In the present invention, the rubber-modified styrenic resin (a) and the propylene resin (b) are mixed at a weight ratio of (a) / (b) = 50 / 50-95 / 5. It is necessary to contain in. When the amount of the rubber-modified styrenic resin (a) is less than the above range, the foaming property is reduced, and a foam having sufficient heat insulating properties cannot be obtained.On the contrary, the propylene-based resin (b) is If the amount is small, the oil resistance and heat resistance of the foam are reduced.

The content ratio (a) / (b) of the two resins is
Taking into account the balance of the properties of the foam such as heat resistance, heat insulation, oil resistance and impact resistance, it is particularly preferable to be about 60/40 to 90/10 within the above range,
More preferably, it is about 5/35 to 80/20.
In addition to the above two resins, a foaming agent for foaming the resin composition is added to the resin composition that forms the resin foam of the present invention. Various additives, such as a foam adjusting agent for adjusting the size, may be added as necessary.

As the foaming agent, any of various known foaming agents such as gaseous, volatile and decomposable types can be used depending on the foaming method of the resin composition. Among the above, examples of the gaseous foaming agent include gases such as carbon dioxide, air, and nitrogen. Examples of the volatile foaming agent include aliphatic hydrocarbons such as propane, n-butane, i-butane, and pentane; cycloaliphatic hydrocarbons such as cyclopentane; trichlorofluoromethane, dichlorofluoromethane, and methyl chloride. And the like, and halogenated hydrocarbons. Further, as a decomposable foaming agent, an organic foaming agent such as azodicarbonamide, dinitrosopentamethylenetetramine, or an inorganic compound obtained by combining a weak acid with an inorganic salt that generates carbon dioxide by a reaction with the weak acid. And a foaming agent. Examples of the inorganic salt include a carbonate or bicarbonate of an alkali metal or an alkaline earth metal (such as sodium bicarbonate), and ammonium carbonate. Examples of weak acids include oxalic acid, malonic acid,
Maleic acid, fumaric acid, succinic acid, itaconic acid, citraconic acid, adipic acid, formic acid, acetic acid, propionic acid, butyric acid, stearic acid, oleic acid, caprylic acid, enanthic acid, caproic acid, valeric acid, lactic acid, tartaric acid, citric acid Organic acids such as acids, phthalic acid, benzoic acid, benzenesulfonic acid, toluenesulfonic acid, chloroacetic acid, and diglycolic acid;
Alternatively, inorganic acids such as boric acid, acidic acids such as calcium acid tartrate, and the like can be mentioned, and among them, citric acid is particularly preferably used.

These foaming agents may be used alone or in combination of two or more. In particular, when the resin foam of the present invention is produced by an extrusion molding method described below, an inorganic system in which a weak acid is combined with an inorganic salt that generates carbon dioxide by reacting with the weak acid by heat during molding. The decomposition type foaming agent is preferably used.

The weak acid and the inorganic salt may be separately added to the resin composition, or both may be coated with a wax or a thermoplastic resin, or added in a master batch state. Good. According to such a combination of a weak acid and an inorganic salt, finer bubbles can be generated as compared with other foaming agents, so that the heat insulating property is improved and the appearance of the foam such as gloss is improved. There are advantages. This effect is achieved by combining the above weak acid with an inorganic salt,
It can also be obtained when used in combination with another blowing agent, for example, a gaseous or volatile blowing agent.

The weak acid and the inorganic salt as the inorganic decomposition type foaming agent include (a) the rubber-modified styrene resin and (b)
Is preferably added in a total amount of 0.01 to 5 parts by weight based on 100 parts by weight of the total amount of the propylene-based resin.
Examples of the cell regulator include inorganic powders such as talc and silica, acidic salts such as polyvalent carboxylic acids, and reaction mixtures of polyvalent carboxylic acids with sodium carbonate or sodium bicarbonate. These foam control agents may be used alone or in combination of two or more.

Other additives other than the cell regulator include, for example, coloring agents, flame retardants, lubricants (hydrocarbons, fatty acids,
Various waxes such as fatty acid amides, esters and alcohols, metal soaps, silicone oil, low molecular weight polyethylene, etc., spreading agents (liquid paraffin, polyethylene glycol, polybutene, etc.), dispersants and the like can be mentioned. These other additives are added to such an extent that they do not hinder the production of the resin foam and do not affect the properties of the produced resin foam.

The method of producing the resin foam of the present invention by producing and foaming a resin composition comprising the above components is not particularly limited. For example, in the case of a resin foam having a continuous shape such as a sheet shape, The following general extrusion molding method is suitably employed. That is, the resin components obtained by dry-blending each of the above-described components of the resin composition and then melting and kneading using an extruder,
The extruder is extruded into the atmosphere from a die attached to the tip of the extruder.

Then, almost simultaneously with the extrusion, the resin composition foams by the action of the foaming agent.
When it is cooled, the resin foam of the present invention having a continuous shape such as a sheet shape is produced. In the above method, when using a solid foaming agent such as a master batch of an inorganic decomposition-type foaming agent and a weak acid as described above, the dry blending step or the subsequent melting It may be added in the kneading step.

When a gaseous or volatile foaming agent is used, it may be pressed into a molten and kneaded resin composition. Specifically, for example, a gaseous or volatile foaming agent may be injected into a resin composition melted and kneaded in the screw cylinder from a nozzle provided in a screw cylinder of the extruder. The rubber-modified styrene-based resin (a) and the propylene-based resin (b) are melted and kneaded using an extruder prepared separately in advance, and attached to the tip of the extruder. After being extruded into the atmosphere from a die having a plurality of small holes and cooled, and then pelletized using a pelletizer, the same resin foam may be used in the extrusion molding of the resin foam described above. Is obtained.

[0034] The resin foam of the present invention is formed into various shapes according to its use. For example, in the case of applications such as the above-described food container, such a food container is usually manufactured by thermoforming a sheet-like resin foam by a vacuum molding method or the like. It is preferably formed in a sheet shape. Next, the laminated foam of the present invention will be described.

The laminated foam of the present invention comprises a non-foamed resin layer on one or both sides of a sheet-shaped resin foam as a raw material thereof in order to improve the appearance and strength of the food container and the like. It is a laminate. Examples of the resin constituting the non-foamed resin layer to be laminated include polystyrene and copolymers of styrene with other vinyl monomers such as (meth) acrylic acid, (meth) acrylic acid ester, and maleic anhydride. Styrene resin, rubber-modified styrene resin obtained by modifying such styrene resin with rubber such as diene rubber, polypropylene, ethylene-propylene block copolymer, ethylene-propylene random copolymer, high-density polyethylene, low-density polyethylene, etc. Olefin resin, polyethylene terephthalate, ethylene-butene copolymer, ethylene-octene copolymer,
And ethylene-propylene copolymer rubber. These resins may be used alone or in combination of two or more. In particular, in consideration of the recycling surface, ease of lamination, balance of physical properties with the foam, and the like, as the resin constituting the non-foamed resin layer, a component similar to the foam is preferably used. Also, commercially available printing films and the like can be used.

The non-foamed resin layer may contain an inorganic filler. As such inorganic fillers,
For example, talc, clay, calcium carbonate, silica, magnesium hydroxide and the like can be mentioned. Various methods can be considered as a method of laminating a non-foamed resin layer on one side or both sides of a sheet-shaped resin foam. When a resin foam sheet is formed by the above-described extrusion method, the number of layers is Only prepared, the tip of the extruder charged with the resin composition that is the base of each layer is fed from the extruder to a die for laminating and laminating the resin extruded and melted from each extruder. At the same time, the so-called co-extrusion method of foaming the resin foam layer while extruding while laminating, is prepared in advance on one or both sides of the resin foam immediately after being extruded into a sheet shape and foamed, A laminating method for simultaneously supplying and laminating a film or sheet extruded by another extruder at the same time as the extrusion of a film or sheet that becomes a non-foamed resin layer or a resin foam. Etc. are suitably employed.

Next, the foam molded article of the present invention will be described. Such a foamed molded article of the present invention is formed by thermoforming by a method such as vacuum molding using the above-mentioned sheet-shaped resin foam or the above-mentioned laminated foam as a raw material. In the above foamed molded article, a resin foam as a raw material is
As described above, heat resistance, heat insulation, excellent oil resistance and impact resistance, and because it is manufactured at low cost, itself is also excellent in each of the above properties, and a highly versatile and inexpensive food container. Become. When a laminated foam is used as the raw material, the appearance and the strength are further improved in addition to the above-mentioned properties.

[0038]

EXAMPLES The present invention will be described below based on examples and comparative examples. Examples 1 to 4, Comparative Examples 1 to 4 A mixture obtained by dry blending the components shown in Tables 1 and 2 below was supplied to a hopper of a tandem type extrusion molding machine having two screw cylinders, Screw diameter φ
While melting and kneading in a 90 mm screw cylinder, butane as a volatile foaming agent was press-fitted from a nozzle provided in the first screw cylinder.

Next, the above resin composition was supplied to a second screw cylinder having a screw diameter of 115 mm, cooled uniformly in the screw cylinder, and then attached to the tip of the second screw cylinder. It was extruded into the atmosphere into a cylinder at a discharge rate of 100 kg / hour from a 170 mm cylindrical die and foamed.

After the obtained cylindrical resin foam was continuously cooled by a cooling mandrel, it was cut continuously at two points on the circumference by a cutter to produce a sheet-like resin foam. . In addition, the specific structure of each component in Tables 1 and 2 is as follows, respectively. (a) Rubber-modified styrenic resin A1: In a continuous phase made of polystyrene, particles of a styrene-butadiene block copolymer are dispersed so as to have a single occlusion type dispersed particle shape, and ethylene-acrylic Rubber-modified styrene resin containing acid ester copolymer [Sumibright DJ9000, trade name, manufactured by Sumitomo Chemical Co., Ltd.] A2: A styrene-butadiene block copolymer in a continuous phase composed of polystyrene Rubber-modified styrene resin in which particles are dispersed to have a single occlusion type dispersed particle shape [trade name: UR- manufactured by Denki Kagaku Kogyo Co., Ltd.]
621] A3: A rubber-modified styrene-based resin in which particles of a styrene-butadiene block copolymer are dispersed in a continuous phase made of polystyrene so as to have a salami structure [trade name 403R manufactured by Asahi Kasei Corporation] (b) ) Propylene resin B1: ethylene-propylene block copolymer [trade name J720N manufactured by Nippon Polyolefin Co., Ltd.] B2: ethylene-propylene block copolymer [trade name AD571 manufactured by Sumitomo Chemical Co., Ltd.] (c) Foaming agent C1: Solid foaming agent in which citric acid and sodium bicarbonate are made into a masterbatch [trade name HK-70 manufactured by Boehringer Ingelheim Chemicals Co., Ltd.] C2: Solid foam in which citric acid and sodium bicarbonate are made into a masterbatch Blowing agent of shape [trade name CF-40S manufactured by Boehringer Ingelheim Chemicals Co., Ltd.] A sheet-like resin foam was used in the same manner as in Examples 1 to 4 and Comparative Examples 1 to 4 except that the components shown in Table 1 were used, and that the components were not melted and butane was not pressed into the kneaded material. Was manufactured.

The following tests were performed on the above Examples and Comparative Examples to evaluate the characteristics. Thickness measurement The thickness of the resin foam of each Example and Comparative Example was measured using a micrometer. Density measurement Each example, the thickness and basis weight of the resin foam of the comparative example were measured, and from these measured values and the density of the resin composition that is the raw material of the resin foam, the following formula was used. Was calculated (g / cm ³ ). The density of the resin composition,
A specific density of each resin component constituting the resin composition,
It was determined from the compounding ratio.

[0042]

(Equation 1)

Measurement of average cell diameter The average cell diameter of the resin foam of each of Examples and Comparative Examples was determined by AST.
It measured according to the measuring method prescribed | regulated to MD-2842-69. Measurement of Izod Impact Strength The Izod impact strength (23 ° C.) of the resin foam of each of Examples and Comparative Examples was measured according to a measurement method specified in JIS K6872.

Heat / Oil Resistance Test The resin foams of Examples and Comparative Examples were 156 mm long and 1 width wide using a foamed styrene sheet molding machine (vacuum molding machine).
It was thermoformed into a 26 mm deep 30 mm baking dish.
The baking dish containing 150 cc of salad oil was placed in a microwave oven and heated, and the temperature of the deformed salad oil was recorded.

The above results are shown in Tables 1 and 2.

[0046]

[Table 1]

[0047]

[Table 2]

From Tables 1 and 2, all of the resin foams of Examples 1 to 5 having the constitution of the present invention have higher resistance to resistance than Comparative Examples 1 and 2 using a conventional rubber-modified styrene resin. It turned out to be excellent in impact properties. This is because, as described above, the conventional rubber-modified styrene-based resin has poor compatibility with the polypropylene-based resin. It is presumed that the impact resistance was greatly reduced due to the dispersion state.

Further, all of the resin foams of the above Examples have improved heat resistance and oil resistance as compared with those of Comparative Example 3 in which the rubber-modified styrenic resin of (a) alone is used, and (b) Comparative Example 4 using propylene resin alone
It was found that the foaming property was better than that of those of Example 1 and fine air bubbles were generated, so that the heat insulating property was excellent. Also, comparing the examples, Examples 2 to 5 using citric acid and sodium bicarbonate could form finer bubbles than Example 1 using only butane as the blowing agent, It was found that the heat insulation could be improved.

[0050]

As described in detail above, according to the present invention,
Provide a novel resin foam, a laminated foam, and a foam molded article using these foams that can be manufactured at a lower cost for food containers and the like having excellent heat resistance, heat insulation, oil resistance, and impact resistance. It has a unique effect of being able to do so.

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Claims (7)

[Claims] (1) In a continuous phase comprising a styrene resin,
A rubber-like polymer containing a single continuous phase made of a styrene-based resin is dispersed, has a single occlusion type dispersed particle shape, and is formed from a group consisting of unsaturated carboxylic acid, unsaturated carboxylic acid ester and vinyl acetate. A rubber-modified styrene-based resin containing a copolymer of at least one selected ethylene and ethylene and (b) a propylene-based resin are mixed in a weight ratio of (a) / (b) = 50.
A resin foam obtained by foaming a resin composition containing the resin composition at a ratio of / 50 to 95/5. 2. The resin foam according to claim 1, wherein the resin foam is foamed by adding at least a weak acid and an inorganic salt which generates carbon dioxide by a reaction with the weak acid to a resin composition as a foaming agent. . 3. The resin foam according to claim 1, which is formed in a sheet shape. 4. A foam molded article obtained by thermoforming the sheet-shaped resin foam according to claim 3. 5. A laminated foam, wherein a non-foamed resin layer is laminated on at least one surface of the sheet-shaped resin foam according to claim 3. 6. The laminated foam according to claim 5, wherein the non-foamed resin layer is an olefin-based resin layer containing an inorganic filler. 7. A foamed molded article obtained by thermoforming the laminated foamed article according to claim 5.