JP3449902B2 - Polycarbonate resin foam - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polycarbonate resin foam. More specifically, the present invention relates to a polycarbonate-based resin foam having improved shape retention at high temperature while maintaining the excellent impact resistance at low temperature (hereinafter referred to as low-temperature impact resistance) of the polycarbonate-based resin. Regarding The polycarbonate resin foam of the present invention can be suitably used for applications such as heat-resistant food containers and frozen food containers.

[0002]

2. Description of the Related Art Polycarbonate resin foams have excellent heat resistance, aging resistance, water resistance, electrical and mechanical properties, and are therefore applicable to industrial materials, building materials, packaging materials, various containers, etc. Is expected. Also, microwave oven containers and retort food containers that require heat resistance, and -5
It is particularly preferably used as a frozen food container that requires low temperature impact resistance up to 0 ° C.

Recently, using this polycarbonate resin,
Extruded foam sheet (for example, JP-A-8-669).
No. 53) has been proposed, but the molded product has sufficient low temperature impact resistance, but since the glass transition temperature of the resin is around 150 ° C., the molded product rapidly increases from around 140 ° C. It is known that the shape-retaining power of the is reduced.
For example, when the contents contain oily substances, if heated in a microwave oven, the container made of polycarbonate resin may exceed 140 ° C. At this time, the container may not retain its shape.

On the other hand, a foam made of a polymer composition of a polymer alloy composed of a polycarbonate resin and a polyethylene terephthalate resin (see JP-A-6-57026),
A foamed polyester sheet made of a resin composition containing a crystalline polyester resin, a polycarbonate resin and an inorganic nucleating agent has been proposed.

[0005]

However, the former foamed sheet has improved surface beauty and strength, but has a low expansion ratio, and a molded product obtained by molding this foamed sheet has the above-mentioned effects. It was questionable whether to have. Also,
The latter foamed polyester sheet has been improved in foaming ratio and high temperature heat resistance, but the low temperature impact resistance at a temperature of around -50 ° C was not satisfactory.

As described above, there has been no foam having a low impact resistance at a temperature of around -50 ° C and a shape-retaining property at a temperature of over 140 ° C and a high expansion ratio.

Therefore, the present invention has been made in view of the above-mentioned prior art, and has excellent shape retention at high temperature while maintaining the excellent low temperature impact resistance of the polycarbonate resin, and the expansion ratio. It is an object of the present invention to provide a polycarbonate-based resin foam having a high openness, a low open cell rate, and an excellent appearance, and a molded article using the same.

[0008]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that a resin composition obtained by adding a polyester resin to a polycarbonate resin having low temperature impact resistance. When or after foaming, by controlling the crystallinity of the foam, it has both excellent low-temperature impact resistance and shape retention at high temperature that can solve such problems, a polycarbonate resin with a high expansion ratio They have found that a foam can be obtained, and completed the present invention.

Thus, according to the present invention, there is provided a foam obtained by adding a crosslinking agent to a resin composition obtained by adding a polyester resin to a polycarbonate resin, and foaming the resin composition. The crystallinity of the resin component is 7
% To 50% of the polycarbonate resin foam is provided.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
First, the polycarbonate resin foam of the present invention is composed of a resin composition obtained by adding a polyester resin to a polycarbonate resin.

The polycarbonate resin referred to in the present invention can be obtained by using carbonic acid and glycol or bisphenol as raw materials. Among polycarbonate resins,
It is preferable to use an aromatic polycarbonate resin having diphenylalkane in the molecular chain. This is because such an aromatic polycarbonate resin has a high melting point and excellent heat resistance, weather resistance and acid resistance. The aromatic polycarbonate-based resin is 2,
2-bis (4-oxyphenyl) propane (also known as bisphenol A), 2,2-bis (4-oxyphenyl) butane, 1,1-bis (4-oxyphenyl) cyclohexane, 1,1-bis (4- Examples include polycarbonate resins derived from bisphenols such as oxyphenyl) isobutane and 1,1-bis (4-oxyphenyl) ethane. Further, as another aromatic polycarbonate resin, a polycarbonate resin containing a polycarbonate component made of poly (ester carbonate) may be mentioned. These are copolyesters having repeating carbonate groups, carboxylate groups and aromatic carbocyclic groups in a linear polymer chain. However, it is preferable to use at least some of the carboxylate groups directly bonded to ring carbon atoms of the aromatic carbocyclic group. In addition to these aromatic polycarbonates, a branched polycarbonate obtained by branching them may be used. The above polycarbonate resins may be used alone or in combination of two or more.

A linear polyester resin which is a polycondensate of an aromatic dicarboxylic acid component and a diol component can be used as the polyester resin in the present invention. Here, as the aromatic dicarboxylic acid component, terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid,
Examples thereof include diphenyl ether dicarboxylic acid, diphenyl sulfone dicarboxylic acid and diphenoxyethane dicarboxylic acid. On the other hand, as the diol component, ethylene glycol, trimethylene glycol, tetramethylene glycol, neopentylene glycol, hexamethylene glycol, cyclohexanedimethylol, 2,2-bis (4-β-hydroxyethoxyphenyl) propane,
4,4′-bis (β-hydroxyethoxy) diphenyl sulfone, diethylene glycol and the like can be mentioned.

Among the polyester resins obtained from these dicarboxylic acids and diols, preferred are polyethylene terephthalate, polybutylene terephthalate,
Examples thereof include polyethylene naphthalate, polybutylene naphthalate, polycyclohexane terephthalate, and polybutylene terephthalate elastomer. In particular, polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate are preferable. The above polyester-based resins may be used alone or in combination of two or more, and a modified resin containing 50% by weight or more of these resins may be used. Further, a recovered product of the polycarbonate-based resin foam according to the present invention may be used.

In particular, the low temperature impact resistance at around -50 ° C. and 1
The component ratio of the polycarbonate resin foam having shape retention at a temperature of more than 40 ° C. is 97 to 50% by weight of the polycarbonate resin and 3 to 50 of the polyester resin.
It is preferably in the weight%. When the proportion of the polyester resin component is more than 50% by weight, the low temperature impact resistance of the resulting foam is deteriorated, which is not preferable. On the other hand, if the amount is less than 3% by weight, it is not preferable because even if the crystallinity of the polyester resin component is increased to the maximum of 50%, the shape retention of the foam at a temperature exceeding 140 ° C cannot be maintained. A more preferable component ratio is 90 to 50% by weight of polycarbonate resin and 10 to 5 of polyester resin.
It is 0% by weight, more preferably 80 to 50% by weight of a polycarbonate resin and 20 to 50% by weight of a polyester resin.

In the present invention, a crosslinking agent may be added to the resin composition obtained by adding the polyester resin to the polycarbonate resin. Although the polyester resin is cross-linked by the cross-linking agent, it is possible to improve the characteristics at the time of foaming due to the melt tension improving effect generated by the cross-linking. Therefore, it is possible to obtain a polycarbonate-based resin foam having improved expansion ratio, open cell ratio, appearance and moldability. In particular, the addition of the crosslinking agent is effective when the proportion of the polyester resin component is high.

The cross-linking agent as referred to in the present invention is a compound or polyfunctional epoxy having at least 4 in one molecule, and two cyclic anhydride groups formed by dehydration condensation of two carboxyl groups. Compounds are preferred. The crosslinking agent selected from these may be used alone or in combination of two or more. Examples of the compound having two anhydride groups in one molecule include pyromellitic dianhydride, naphthalenetetracarboxylic dianhydride, benzophenonetetracarboxylic dianhydride, cyclopentanetetracarboxylic dianhydride, ethylene glycol ( Anhydro trimellitate), glycerol (anhydro trimellitate) and the like.
Among these, pyromellitic dianhydride and benzophenonetetracarboxylic dianhydride are particularly preferable.

As the polyfunctional epoxy compound, diglycidyl terephthalate, diglycidyl orthophthalate, diglycidyl hexahydrophthalate, and tetrafunctional nitride epoxy (for example, TETRAD-D manufactured by Mitsubishi Gas Chemical Co., Inc.)
, Polyethylene glycol diglycidyl ether, polypropylene diglycidyl ether, bisphenol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether, hydrogenated BP- A diglycidyl ether, 2,2-dibromo neopentyl glycol diglycidyl ether and the like can be mentioned. Of these, diglycidyl terephthalate, diglycidyl orthophthalate, diglycidyl hexahydrophthalate, 4
Functionalized nitrided epoxies are particularly preferred.

The amount of the crosslinking agent used may be appropriately adjusted depending on the extrusion conditions, the desired expansion ratio, etc., but is preferably 0.01 to 5.0 parts by weight with respect to 100 parts by weight of the polyester resin. If the amount of the crosslinking agent is less than 0.01 parts by weight, the effect of improving the melt tension of the resin composition cannot be obtained, which is not preferable. On the other hand, if the amount is more than 5.0 parts by weight, the resin composition gels and cannot be foamed under stable conditions, which is not preferable.

Furthermore, it is preferable that the resin composition containing the crosslinking agent of the present invention contains at least one metal or a compound thereof. By including a metal or a compound thereof, the above-mentioned crosslinking effect, that is, the melt tension improving effect can be promoted.

Examples of the metal and its compound include aluminum and calcium as the metal, metal carbonates such as sodium carbonate, calcium carbonate, zinc carbonate and magnesium carbonate, and sodium montanate as the metal compound.
Examples thereof include fatty acid metal salts such as zinc stearate and potassium palmitate. These may be used alone or in combination of two or more.

Such a metal or its compound is preferably used in an amount of 1 to 100 parts by weight, more preferably 5 to 60 parts by weight, based on 100 parts by weight of the crosslinking agent.

In addition to the above-mentioned crosslinking agent and metal or its compound, known additives which are added to ordinary extruded foams may be added to the polycarbonate resin foam within a range not impairing the object of the present invention. it can. As such known additives, a cell regulator, a stabilizer, a flame retardant,
An antistatic agent, a coloring agent, etc. are mentioned.

Among the above-mentioned known additives, the cell regulator can be added as necessary in order to smoothly foam the resin composition comprising the polycarbonate resin and the polyester resin. Examples of the bubble regulator include inorganic powders such as talc, silica, mica, and mica, acidic salts such as polyvalent carboxylic acids, and mixtures of polyvalent carboxylic acids with sodium carbonate or sodium bicarbonate. These cell regulators may be used alone or in combination of two or more. The amount added is 0.01 to 100 parts by weight of the resin composition.
The amount is preferably 5.0 parts by weight, more preferably 0.05 to 3.0 parts by weight. If the amount is less than 0.01 parts by weight, a sufficient bubble control effect cannot be obtained, which is not preferable.
On the other hand, if the amount is more than 5.0 parts by weight, the cell diameter becomes too small, and the physical properties and moldability of the resulting foam are deteriorated, which is not preferable.

The polycarbonate resin foam of the present invention contains a polycarbonate resin having excellent low-temperature impact resistance and a crystalline polyester resin. Therefore, in order to obtain a foam having both excellent low temperature impact resistance and shape retention at high temperature, which is the object of the present invention,
The crystallinity of the polyester resin component in the polycarbonate resin foam is appropriately adjusted within the range of 7 to 50% according to the ratio of the polyester resin component. Generally, when the proportion of the polyester resin component is low, a polyester resin having a relatively high crystallinity is used, and when the proportion is high, a polyester resin having a relatively low crystallinity is used. More preferable crystallinity is 10 to 40%
Within the range of.

Generally, the crystallization temperature of the polyester resin is in the range of 110 ° C to 220 ° C. Therefore, the crystallinity of the polyester resin component in the polycarbonate resin foam is achieved by keeping the polycarbonate resin foam within this temperature range.

There are two methods of controlling the crystallinity in the present invention. The first is a method of controlling until the expansive gel immediately after foaming is cooled down to the ambient temperature (control method 1), and the second is a polycarbonate resin foam cooled to the ambient temperature and further subjected to a crystallization temperature range. It is a method (control method 2) of controlling by heating to. Only the control method 1 or 2 may be used, or both the control method 1 and the control method 2 may be performed. In order to control the crystallinity to be higher, it is preferable to carry out both the control methods 1 and 2. further,
When thermoforming the polycarbonate resin foam of the present invention to obtain a molded article, it is preferable to carry out only the control method 2 in consideration of the moldability during thermoforming, that is, the elongation of the foamed sheet.

The control method 1 is, for example, for a foam formed by heating and kneading a polycarbonate resin, a polyester resin and optionally a foaming agent in an extruder and extruding the obtained molten gel into a low pressure region. In the manufacturing method, immediately after the molten gel having a crystallization temperature or higher is extruded into the low pressure region, a medium whose temperature is controlled by heating (for example, air, warm water, steam, etc.), a temperature controlled mold (temperature control plate, Adjusting the foam within the crystallization temperature range by using a mandrel that is heated at the time of manufacturing the tubular foam, etc.
It is a method of controlling crystallization.

In the control method 2, for example, a foamed sheet extruded and foamed into a sheet by a circular die or a flat die is reheated to a crystallization temperature range by using a roll or plate whose heating temperature is controlled, and the crystallinity is increased. There is a method of controlling. Also, in the heating step, it is heated to be in a softened state, and is pressed into the molding die in the molding step to be molded,
In thermoforming, which is a molded article, the crystallinity may be controlled by adjusting the foam within the crystallization temperature range in the heating step, the molding step, or both the heating step and the molding step. In consideration of moldability, it is preferable to control the crystallinity in the molding process. In any of the above control methods 1 and 2, the foam is held within the crystallization temperature for a desired time in order to obtain the desired crystallinity, but it is particularly preferred to hold the foam for 2 seconds to 4 minutes. .

The method for producing a polycarbonate resin foam according to the present invention includes heating a polycarbonate resin, a polyester resin and optionally a foaming agent in an extruder.
An extrusion foaming method in which a molten gel obtained by kneading and extruding the molten gel through the mold to a low pressure region to obtain a foamed body is preferable. The shape of the mold is attached to the tip of the extruder according to the desired shape of the foam. For example, when extruding a polycarbonate-based resin foam into a sheet shape, a flat die or a circular die is attached, when extruding into a cylindrical shape, a nozzle die is attached, and when extruding into a board shape, a flat die or a multi-nozzle die is attached. It is preferable to attach it. The foam extruded into various shapes from the mold is adjusted within the crystallization temperature range by, for example, a temperature-controlled cylindrical mandrel, rolls or two molding plates above and below, while controlling the crystallinity. , Continuously taken over.

Any known foaming agent can be used as the foaming agent. The foaming agent can be roughly classified into a physical foaming agent and a chemical foaming agent. Among them, the physical foaming agent is preferably used from the viewpoint of improving the expansion ratio. Physical blowing agents are further classified into inert gas, saturated aliphatic hydrocarbons, saturated alicyclic hydrocarbons, halogenated hydrocarbons, ethers, ketones, etc., any of which can be used in the present invention. . Typical examples include carbon dioxide gas, nitrogen, etc. as the inert gas, and propane, normal or isobutane, normal or isopentane, or a mixture thereof as the saturated aliphatic hydrocarbon. Examples of group hydrocarbons include cyclohexane, examples of halogenated hydrocarbons include methyl chloride, ethyl chloride, various freons, etc., examples of ethers include dimethyl ether, methyl tert-butyl ether, etc., examples of ketones include acetone, etc. Is mentioned.
The foaming agents detailed above may be used alone or in combination of two or more.

The range of the expansion ratio of the polycarbonate resin foam of the present invention is preferably 2-30. Therefore, it is preferable to use the foaming agent so as to be in this range. In addition, when the expansion ratio of the polycarbonate-based resin foam of the present invention is less than 2, the heat insulating performance is deteriorated and the weight reduction effect becomes poor, which is not preferable. On the other hand, the expansion ratio is 30
If it exceeds, the cell membrane becomes thin and it is difficult to obtain closed cells,
It is not preferable because the strength decreases. The polycarbonate resin foam of the present invention may be a molded product obtained by further thermoforming the foam. The molded product is formed by, for example, appropriately thermoforming according to the application to industrial materials, building materials, packaging materials, various containers, and the like. Of these, molded products such as microwave oven containers, retort food containers, and frozen food containers are particularly preferable.

[0032]

EXAMPLES The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In Examples and Comparative Examples, the crystallinity, open cell rate, low temperature impact resistance, and shape retention were measured by the following methods.

Crystallinity measurement method About 7 mg of a sample was cut from a foamed molded product, and SEIKO was cut.
Using a differential scanning calorimeter DSC200 type manufactured by Denshi Kogyo Co., Ltd., the temperature was raised from 40 ° C to 290 ° C at a rate of 5 ° C / minute,
At that time, the amount of crystallization heat (A) (mJ / mg) and the amount of heat of fusion of all crystals (B) (mJ / mg) are measured. Next, assuming that the proportion of the polyester resin component of the foam is (C)% by weight, the crystallinity of the polyester resin component of the foam molded product is determined by the following formula. Crystallinity = [{B / (C × 1/100) −A / (C × 1 /
100)} / K] × 100 (where K is the literature value of the heat of crystallization (mJ / mg) when the polyester resin is 100% crystallized,
For example, with polyethylene terephthalate resin, 140.
It becomes 1 (mJ / mg).

Method of measuring open cell ratio A cube having a side of about 2.5 cm was made from the obtained foam,
The apparent volume is measured using a caliper. Next, the true volume of the cube is measured using an air comparison type hydrometer manufactured by Tokyo Science Co., Ltd. When the apparent volume is A and the true volume is V, the open cell ratio is calculated by the following equation. Open cell rate = (A−V) / A × 100

Method for measuring low temperature impact resistance A tray-shaped molded product having a long side of 175 mm, a short side of 125 mm and a depth of 26 mm was fixed with the bottom thereof facing upward, and an iron ball having a weight of 291 g was dropped from a height of 35 cm to mold the molded product. Measure the temperature at which the item is destroyed. The result obtained by this test is an index for judging low temperature impact resistance.

Method of Measuring Shape Retention A state of the molded product before and after heating a tray-shaped molded product having a long side of 175 mm, a short side of 125 mm and a depth of 26 mm at 160 ° C. for 10 minutes is observed. Depending on the degree of deformation of the molded product, if it deforms significantly and does not retain its original shape x,
The sample that is slightly deformed but retains the original shape is evaluated as Δ, and the sample that is hardly deformed is evaluated as ○.

Example 1 Polycarbonate resin having an average molecular weight of 23500 and I.V.
V. Polyethylene terephthalate resin having a value (intrinsic viscosity) of 1.0 is added to 100 parts by weight of a base resin composed of 90% by weight and 10% by weight, respectively, and 0.1 parts by weight of pyromellitic dianhydride (crosslinking agent) and sodium carbonate. 0.01 parts by weight and 0.9 parts by weight of talc as a cell adjuster were mixed and fed to an extruder for melt kneading. Then, a melt-kneaded product obtained by press-fitting isopentane 0.30 mol / kg resin into the extruder was extruded into a cylindrical shape from a circular die (diameter 80φ, slit 0.4 mm) attached to the tip of the extruder. Then, while the tubular foam is taken out by a take-out machine, a balloon is formed inside and outside the foam with room temperature air, cooled with a mandrel in which water adjusted to 35 ° C is circulated, and then cut open to form a foam sheet. Obtained.

Next, using a hot plate molding machine, the foamed sheet is preheated to 160 ° C. in the heating step and further molded to a temperature of 190 ° C. in the molding step, and is molded with a die having a long side 175.
A tray-shaped molded product having a size of mm, a short side of 125 mm, and a depth of 26 mm was obtained. Foaming ratio and thickness of the obtained foamed sheet, crystallinity of polyethylene terephthalate resin in the foamed sheet, open cell ratio, crystallinity of polyethylene terephthalate resin in molded products, low temperature impact resistance of molded products, molded products 160 ℃
Table 1 shows the shape-retaining property.

Example 2 The proportions of polycarbonate resin and polyethylene terephthalate resin were changed to 80% by weight and 20% by weight, respectively,
0.15 parts by weight of pyromellitic dianhydride, 0.25 mol / kg of butane (a mixture of 65% by weight of normal butane and 35% by weight of isobutane) as a foaming agent, and sodium carbonate were not added. In the same manner as in Example 1, a foamed sheet and a molded product using the foamed sheet were produced. Magnification and thickness of the obtained foamed sheet, crystallinity of polyethylene terephthalate resin in the foamed sheet, open cell ratio, crystallinity of polyethylene terephthalate resin in molded products, low temperature impact resistance of molded products, The shape retention properties at 160 ° C. are shown in Table 1.

Example 3 Using the foamed sheet obtained in Example 2, it was preheated to 145 ° C. in a heating step with a hot plate forming machine, and further heated in a forming step.
It was molded with a mold heated to 80 ° C. The obtained molded product has a long side of 175 mm, a short side of 125 mm, and a depth of 26 m.
It was a m-shaped tray. The crystallinity of the polyethylene terephthalate resin in the obtained molded product, low temperature impact resistance, 16
The shape retention properties at 0 ° C. are shown in Table 1.

Example 4 The proportions of polycarbonate resin and polyethylene terephthalate resin were changed to 70% by weight and 30% by weight, respectively,
0.18 parts by weight of pyromellitic dianhydride, 0.03 parts by weight of sodium carbonate, and 0.20 mol of butane as a blowing agent.
A foamed sheet was obtained in the same manner as in Example 1 except that kg resin was used. Next, using a hot plate molding machine, the foamed sheet was preheated to 170 ° C. in the heating step, and was molded with a mold heated to 200 ° C. in the molding step. The obtained molded product was in the shape of a tray having a long side of 175 mm, a short side of 125 mm and a depth of 26 mm. Magnification and thickness of the obtained foamed sheet, crystallinity of polyethylene terephthalate resin in the foamed sheet, open cell ratio, crystallinity of polyethylene terephthalate resin in molded products, low temperature impact resistance of molded products, The shape retention properties at 160 ° C. are shown in Table 1.

Example 5 (Reference Example) Pyromellitic dianhydride and sodium carbonate were not added,
Except that the foaming agent was butane 0.29 mol / kg resin,
A foamed sheet and a molded product using the foamed sheet were prepared in the same manner as in Example 4. Magnification and thickness of the obtained foamed sheet, crystallinity of polyethylene terephthalate resin in the foamed sheet, open cell ratio, crystallinity of polyethylene terephthalate resin in molded products, low temperature impact resistance of molded products, The shape retention properties at 160 ° C. are shown in Table 1.

Example 6 The proportions of polycarbonate resin and polyethylene terephthalate resin were changed to 60% by weight and 40% by weight, respectively,
A foamed sheet and the foamed sheet in the same manner as in Example 4 except that 0.16 parts by weight of pyromellitic dianhydride, a blowing agent of 0.33 mol / kg resin were used, and sodium carbonate was not added. A molded product using was prepared. Magnification, thickness of the obtained foamed sheet, crystallinity of polyethylene terephthalate resin in the foamed sheet, open cell rate,
Table 1 shows the crystallinity of the polyethylene terephthalate resin in the molded product, the low temperature impact resistance of the molded product, and the shape retention of the molded product at 160 ° C.

Example 7 A foamed sheet and a molded article using the foamed sheet were prepared in the same manner as in Example 6 except that butane was 0.54 mol / kg resin as the foaming agent. Magnification and thickness of the obtained foamed sheet, crystallinity of polyethylene terephthalate resin in the foamed sheet, open cell ratio, crystallinity of polyethylene terephthalate resin in molded products, low temperature impact resistance of molded products, The shape retention properties at 160 ° C. are shown in Table 1.

Example 8 I. V. Using a polyethylene terephthalate resin with a value of 0.75, 0.20 parts by weight of pyromellitic dianhydride,
A foamed sheet and a molded article using the foamed sheet were prepared in the same manner as in Example 4 except that 0.05 part by weight of sodium carbonate was used and talc was not added. Magnification and thickness of the obtained foamed sheet, crystallinity of polyethylene terephthalate resin in the foamed sheet, open cell ratio, crystallinity of polyethylene terephthalate resin in molded products, low temperature impact resistance of molded products, The shape retention properties at 160 ° C. are shown in Table 1.

Comparative Example 1 A foamed sheet was obtained in the same manner as in Example 2 except that 100 parts by weight of a branched polycarbonate resin having an average molecular weight of 24500 was used and pyromellitic dianhydride was not added. The foamed sheet was preheated to 145 ° C. in a heating step with a hot plate molding machine and then molded in a molding step. The obtained molded product was in the shape of a tray having a long side of 175 mm, a short side of 125 mm and a depth of 26 mm. Table 1 shows the magnification, thickness, open cell ratio, low temperature impact resistance of the molded product, and shape retention of the molded product at 160 ° C. of the obtained foamed sheet.

[0047]

[Table 1]

As is clear from Table 1, the molded articles of the examples had good low-temperature impact resistance such that they did not break even at -70 ° C, and also had good shape retention at 160 ° C.

[0049]

According to the polycarbonate resin foam of the present invention, it is possible to surprisingly improve the shape retention of the container at high temperature while maintaining the excellent low temperature impact resistance of the polycarbonate resin. It will be possible.

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Claims (5)

(57) [Claims] 1. A crosslinking agent is added to a resin composition obtained by adding a polyester resin to a polycarbonate resin.
A foam made by foaming Te, the polycarbonate-based resin foam, wherein the crystallinity of the polyester resin component of the foam is 7% to 50%. 2. A compound and a polyfunctional epoxy compound in which the cross-linking agent has at least four carboxyl groups in one molecule and two cyclic anhydride groups formed by dehydration condensation of two of the carboxyl groups. The foam according to claim 1 , wherein at least one kind is selected from the following. 3. The resin composition further has a crosslinking effect by a crosslinking agent.
The foam according to claim 1 or 2 , containing at least one kind of a metal capable of promoting fruit or a compound thereof. 4. A foam, foam according to any one of Claims 1-3 having 2-30 fold expansion ratio. 5. A foam, foam according to any one of Claims 1-4 is thermoformed moldings.