JP2003096226A - Foamable polycarbonate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a foamable polycarbonate resin composition which improves the surface properties and strength of a molded product. SOLUTION: Polycarbonate resins of 100 pts.wt., (meth)acrylic acid ester polymer or the polymer mixture having a specific viscosity of 0.65 to 1.7 of 0.5 to 30 pts.wt. which is produced by the polymerization of acrylic acid ester monomer of 0 to 50 pts.wt. in the presence of polymer latex having a specific viscosity of 0.7 to 1.9 obtained by the polymerization of methyl methacrylate monomer of 50 to 100 pts.wt., a filler of 0.1 to 30 pts.wt. and a foaming agent are combined. Talc, mica, wollastonite, clay or glass fiber is preferable as the filler. A thermolysis-type foaming agent is preferable as the foaming agent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a foamable polycarbonate resin composition. More specifically, the present invention relates to a foamable polycarbonate resin composition which is excellent in processability at low temperature, and also provides low-temperature brittleness, heat resistance, dimensional stability, water resistance, mechanical properties, and a high-magnification foam molding excellent in acid resistance. .

[0002]

2. Description of the Related Art Polycarbonate resins are used for bottles, sheets, to give molded articles excellent in physical properties such as low-temperature brittleness, heat resistance, dimensional stability and mechanical properties and chemical properties such as water resistance and acid resistance. It is widely used in packaging materials such as films and various other fields. Further, in recent years, a foam molding method has been attracting attention as a means for reducing the weight of a polycarbonate resin, improving the heat insulating property, and reducing the cost of a molded product, and there is a strong demand from the market for a molded product of a polycarbonate resin with a high magnification.

In the foam molding of the polycarbonate resin, a method of using a combination of a polycarbonate resin and a foaming agent is generally known.

Further, it is known that when an acrylic resin is added in addition to the polycarbonate resin and the foaming agent, high-magnification foam molding is possible.

For example, in Japanese Patent Laid-Open No. 2000-136301, an acrylic resin is added to an alloyed resin of polycarbonate and another aromatic ring-containing thermoplastic resin to give a foaming ratio of 1.6 to 3.0. It is described that a foamed molded product can be obtained.

Further, Japanese Patent Laid-Open No. 10-330524,
And JP-A-10-329206 describes that the expansion ratio of a foamed molded article can be improved by adding an acrylic resin having a viscosity average molecular weight of 100,000 to 400,000, and 200,000 to 1.3 million to a polycarbonate resin. ing.

However, even with these techniques, the foaming performance is not sufficient and the surface properties of the molded product are also insufficient.

The present invention comprises (co) polymerizing a monomer mixture having a specific composition and having a specific specific viscosity (meth).
It is possible to further improve the foamability by using an acrylate polymer or a polymer mixture. Further, addition of a filler can improve the decrease in strength of the foamed molded product due to the improvement of the expansion ratio, which is different from this technique. The lower limit of the specific viscosity of the (meth) acrylic acid ester-based polymer used here is 0.65, which is at least about 3.2 million when converted into a viscosity average molecular weight, and (meth) having a lower molecular weight than this.
It is different from those used in these techniques in that the foamability is remarkably improved as compared with the case where an acrylate polymer is used.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to significantly improve the expansion ratio in the foam molding of a polycarbonate resin, and to improve the strength of the foam-molded product, which occurs with the improvement of the expansion ratio. An object of the present invention is to provide a foamable polycarbonate resin composition capable of improving deterioration and deterioration of surface property.

[0010]

As a result of intensive studies, the present inventors have found that a specific (meth) acrylic acid ester polymer or polymer mixture, a filler and a foaming agent are added to a polycarbonate resin. Thus, the inventors have found that a composition capable of significantly improving the expansion ratio and improving the strength and surface property of the foamed molded product is obtained, and have completed the present invention.

That is, the present invention comprises (A) 100 parts by weight of a polycarbonate resin and (B) methyl methacrylate 51.
˜100% by weight, 0 to 49% by weight of at least one monomer selected from methacrylic acid esters and acrylic acid esters other than methyl methacrylate, and vinyl monomers 0 to 20 copolymerizable therewith % Of the monomer mixture (a), which is obtained by emulsion polymerization, and 0.1 g of the polymer dissolved in 100 ml of chloroform has a specific viscosity at 30 ° C. of 0.7. ~
In the presence of a polymer latex of 1.9, at least one monomer 51 to 0-49% by weight of methyl methacrylate, at least one monomer selected from methacrylic acid ester and acrylate ester excluding methyl methacrylate 100% by weight
And 0 to 50 parts by weight of a monomer mixture (b) consisting of 0 to 20% by weight of a vinyl-based monomer copolymerizable therewith, 100 parts by weight of [(a) and (b) in total] are polymerized. The obtained polymer or polymer mixture is characterized in that a solution of 0.1 g of the polymer or polymer mixture dissolved in 100 ml of chloroform has a specific viscosity at 30 ° C. of 0.65 to 1.7 ( A foamable polycarbonate resin composition containing 0.5 to 30 parts by weight of a (meth) acrylic acid ester-based polymer or polymer mixture, 0.1 to 30 parts by weight of a (C) filler, and (D) a foaming agent ( Claim 1), the filler (C) is talc, calcium carbonate, mica, wollastonite, clay or glass fiber, and the expandable polycarbonate resin composition (claim 2), foaming agent (D). Is a pyrolytic foam 0.1 to 25 parts by weight of the expandable polycarbonate resin composition according to claim 1 or 2 (claim 3) and the foamed molded product obtained by molding the expandable polycarbonate resin composition according to claim 1 (claim 3). Regarding 4).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION A feature of the present invention is a polymer or a polymer mixture obtained by emulsion-polymerizing a monomer or a monomer mixture containing a specific amount of a specific methacrylic acid ester and / or acrylic acid ester. Is used for the purpose of improving the foamability of the polycarbonate resin. By using the (meth) acrylic acid ester-based polymer or polymer mixture, the foaming agent and the filler, it is possible to increase the expansion ratio during foam molding without impairing the excellent physical and chemical properties originally possessed by the polycarbonate resin. The effect of being able to improve can be expressed.

The polycarbonate resin used in the present invention is an aromatic polycarbonate, and a polycarbonate ester formed from an aromatic diol component such as a carbonic acid component and a bisphenol compound, or a diol component mainly containing the same, or those. Is a mixture of. Among these, aromatic polycarbonate resins having diphenylalkane in the molecular chain are preferable because they are excellent in heat resistance, weather resistance, and acid resistance. Examples of such a polycarbonate resin include 2,2-bis (4-oxyphenyl) propane (bisphenol A), 2,2-bis (4-oxyphenyl) butane, and 1,1-bis (4-oxyphenyl) cyclohexane. , 1,1-bis (4-oxyphenyl) isobutane, 1,1-bis (4-oxyphenyl) ethane, and other polycarbonate resins formed from bisphenol compounds.

The (meth) acrylic acid ester-based polymer or polymer mixture used in the present invention is a monomer mixture (a).
Which is composed of a polymer mixture obtained by adding the monomer mixture (b) in the presence of a latex of a polymer obtained by emulsion polymerization, and is used for the purpose of improving the foamability of the polycarbonate resin. It is a component.

The monomer mixture (a) comprises 51 to 100% (% by weight, the same applies hereinafter) of methyl methacrylate, preferably 6%.
0-90%, more preferably 70-85%, and a monomer selected from methacrylic acid esters and acrylic acid esters other than methyl methacrylate, 0-49%, preferably 10-40%, more preferably 0-30%,
It is a mixture of 0 to 20%, preferably 0 to 10%, and more preferably 0 to 5% of a vinyl-based monomer copolymerizable with these.

If the proportion of methyl methacrylate in the monomer mixture (a) is less than 51%, the foamability and processability will deteriorate. Further, when the monomer selected from the methacrylic acid ester and the acrylic acid ester excluding the above-mentioned methyl methacrylate exceeds 49%, the foamability and processability are deteriorated. Furthermore, there are 20 vinyl-based monomers copolymerizable with these.
If it exceeds%, the foamability and processability will be reduced.

Specific examples of the methacrylic acid ester excluding methyl methacrylate in the monomer mixture (a) include alkyl groups such as ethyl methacrylate, propyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate. Examples thereof include methacrylic acid alkyl esters having 2 to 8 carbon atoms. Specific examples of the acrylate ester include alkyl acrylates having 1 to 8 carbon atoms in the alkyl group such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. Examples include esters. These methacrylic acid esters and acrylic acid esters other than methyl methacrylate may be used alone or in combination of two or more.

Specific examples of the vinyl monomer copolymerizable with these in the monomer mixture (a) include aromatic vinyl such as styrene and α-methylstyrene and unsaturated nitrile such as acrylonitrile. Can be given. These may be used alone or in combination of two or more.

0.1 g of the polymer obtained by emulsion polymerization of the monomer mixture (a) was dissolved in 100 ml of chloroform, and the specific viscosity measured at 30 ° C. was 0.7 to 1.9.
Preferably 0.8-1.8, more preferably 0.8-
1.7, particularly preferably 0.9 to 1.6. If the specific viscosity exceeds 1.9, the foamability and processability tend to deteriorate. When the specific viscosity is less than 0.7, the foamability and the surface property of the molded product tend to be deteriorated.

The monomer mixture (b) contains 0 to 49% of methyl methacrylate, preferably 20 to 49%, more preferably 30 to 45% of methyl methacrylate and acrylic acid ester excluding methyl methacrylate. 51 to 100%, preferably 51 to 80%, more preferably 55 to 70%, and 0 to 20% of a vinyl-based monomer copolymerizable therewith, preferably It is composed of 0 to 10%, more preferably 0 to 5%.

By polymerizing the monomer mixture (b) in the presence of a latex of the polymer from the monomer mixture (a) to provide the outer layer with the polymer from the mixture (b),
When the (meth) acrylic acid ester-based polymer or polymer mixture is added to the polycarbonate resin, viscosity and elasticity can be efficiently imparted to the polycarbonate resin, and as a result, foamability can be improved.

When the proportion of methyl methacrylate in the monomer mixture (b) exceeds 50%, good foamability and processability tend to be lost. The same applies when the proportion of at least one monomer selected from the methacrylic acid esters and acrylic acid esters excluding methyl methacrylate is less than 50%. Further, the vinyl-based monomer copolymerizable with these can be used in a range not exceeding 20% if necessary, but it is preferable that the amount is as small as possible.

Specific examples of the methacrylic acid ester excluding methyl methacrylate in the monomer mixture (b) include alkyl groups such as ethyl methacrylate, propyl methacrylate, butyl methacrylate, and 2-ethylhexyl methacrylate. Examples thereof include methacrylic acid alkyl esters having 2 to 8 carbon atoms. Specific examples of the acrylate ester include alkyl acrylates having 1 to 8 carbon atoms in the alkyl group such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate. Examples include esters. These methacrylic acid esters and acrylic acid esters other than methyl methacrylate may be used alone or in combination of two or more.

Specific examples of the vinyl monomers copolymerizable with these in the monomer mixture (b) include aromatic vinyl such as styrene and α-methylstyrene, and unsaturated nitrile such as acrylonitrile. And so on.
These may be used alone or in combination of two or more.

The polymer or polymer mixture obtained by adding and polymerizing the monomer mixture (b) in the presence of the latex of the polymer obtained from the monomer mixture (a) is the polymer or polymer. 0.1 g of the combined mixture was dissolved in 100 ml of chloroform, and the specific viscosity measured at 30 ° C. was 0.65 to 1.7.
And preferably 0.65 to 1.6, more preferably 0.7 to 1.5. If the specific viscosity exceeds 1.7, the foamability and processability tend to deteriorate. Specific viscosity is 0.65
If it is less than the range, the foamability and the surface property of the foamed molded product tend to be deteriorated.

The ratio of the monomer mixture (a) and the monomer mixture (b) used for producing the (meth) acrylic acid ester-based polymer or polymer mixture of the present invention is 100 in total. Monomer mixture (a) 50 to 100 parts, preferably 60 to 95 parts, more preferably 65 to 90 parts, and monomer mixture (b) 0 to 0 parts by weight (the same applies hereinafter).
50 parts, preferably 5 to 40 parts, more preferably 10 parts
~ 35 parts.

If the amount of the polymer formed from the monomer mixture (a) is less than about 50 parts, the polycarbonate resin cannot have sufficient foamability. Further, when the amount of the polymer formed from the monomer mixture (b) exceeds 50 parts, similarly, the foamability of the polycarbonate resin cannot be sufficiently imparted.

The (meth) acrylic acid ester-based polymer or polymer mixture of the present invention can be produced, for example, by the following method. First, the monomer mixture (a) is emulsion polymerized in the presence of a suitable medium, an emulsifier, a polymerization initiator, a chain transfer agent, etc. to obtain a polymer latex from the monomer mixture (a). Then, the monomer mixture (b) is sequentially added to carry out polymerization. By sequentially polymerizing each mixture in this manner, the (co) polymer from the monomer mixture (a) becomes the inner layer and the (co) polymer from the monomer mixture (b) becomes the outer layer. A staged or two stage polymer blend is produced. The dispersion medium used in the emulsion polymerization is usually water.

Known emulsifiers are used as the emulsifier. For example, anionic surfactants such as fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonate salts, alkyl phosphate ester salts, sulfosuccinic acid diester salts, and nonionic interfaces such as polyoxyethylene alkyl ethers and polyoxyethylene fatty acid esters. Examples include activators.

As the polymerization initiator, a water-soluble or oil-soluble polymerization initiator or the like is used. For example, an ordinary inorganic polymerization initiator such as persulfate, or an organic peroxide, an azo compound or the like may be used alone, but these initiator compounds and sulfites, thiosulfates, first metal salts, sodium may be used. In combination with formaldehyde sulfoxylate,
It may be used in a redox system. Preferred persulfates include, for example, sodium persulfate, potassium persulfate, ammonium persulfate and the like, and preferred organic peroxides include, for example, t-butyl hydroperoxide, cumene hydroperoxide, benzoyl peroxide, Examples include lauroyl peroxide.

The chain transfer agent is not particularly limited, but for example, t-dodecyl mercaptan, n-dodecyl mercaptan, t-decyl mercaptan, n-decyl mercaptan and the like can be used.

The temperature and time during the polymerization reaction are not particularly limited, and may be appropriately adjusted so as to obtain a desired specific viscosity and particle size according to the purpose of use.

When the polymerization is carried out by the two-step polymerization, it is necessary to confirm that the first-step polymerization is completed before adding the second-step and subsequent monomers, and then add the first-step monomer. Each stage of polymerization can be carried out without mixing with.

The particles in the polymer latex thus obtained usually have an average particle size of about 100 to 3000 liters, and salting out, coagulation by adding an ordinary electrolyte, spraying in hot air, and drying. To be removed from the latex. If necessary, washing, dehydration, drying and the like are carried out by usual methods.

The (meth) acrylic acid ester-based polymer or polymer mixture obtained by the above operation is usually a white powdery powder having an average particle diameter of 30 to 300 μm. It is preferable for blending with a polycarbonate resin as a polymer mixture.

The expandable polycarbonate resin composition of the present invention is produced by mixing the (meth) acrylic acid ester-based polymer or polymer mixture of the present invention with a polycarbonate resin according to a conventional method.

The amount of the (meth) acrylic acid ester-based polymer or polymer mixture added is 0.5 to 30 parts, preferably 3 to 100 parts with respect to 100 parts of the polycarbonate resin.
25 parts, and more preferably 5 to 20 parts. (Meta)
If the amount of the acrylic acid ester-based polymer or polymer mixture added is less than 0.5 parts by weight, the effect of adding the (meth) acrylic acid ester-based polymer or polymer mixture cannot be sufficiently obtained and exceeds 30 parts. If so, the excellent mechanical properties of the polycarbonate resin are impaired.

The foaming agent used in the present invention is not particularly limited, and is an inert gas such as nitrogen gas, carbon dioxide gas, helium, etc., saturated hydrocarbons such as propane, butane, pentane, hexane, etc., and tetrafluorocarbon. Physical blowing agents such as halogenated hydrocarbons such as methane and freon, sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate,
Pyrolytic inorganic foaming agents such as sodium carbonate and ammonium carbonate, nitroso compounds such as N, N′-dinitrosopentamethylenetetramine, N, N′-dimethyl-N, N′-dinitrosoterephthalamide, azodicarbonamide, Azobisisobutyronitrile, azo compounds such as barium azodicarboxylate, benzenesulfonyl hydrazide, thermally decomposable organic foaming agents such as sulfonyl hydrazide compounds such as toluenesulfonyl hydrazide, thermal decomposition type foaming agents such as, is used, The thermal decomposition type foaming agent is preferable from the viewpoint of foaming efficiency and the fact that foaming molding equipment provided with an explosion-proof structure may not be used.

Examples of the thermal decomposition type inorganic foaming agent include sodium bicarbonate, potassium bicarbonate, ammonium bicarbonate, sodium carbonate, ammonium carbonate and the like. These may be used alone or in combination of two or more. Among them, sodium bicarbonate is preferable in terms of foaming efficiency and cost.

Examples of the thermal decomposition type organic foaming agent include N, N'-dinitrosopentamethylenetetramine, N, N
Nitroso compounds such as N'-dimethyl-N, N'-dinitrosoterephthalamide, azo compounds such as azodicarbonamide, azobisisobutyronitrile and barium azodicarboxylate, sulfonyls such as benzenesulfonyl hydrazide and toluenesulfonyl hydrazide Examples include hydrazide compounds. These may be used alone or in combination of two or more. Among them, azodicarbonamide is preferable in terms of foaming efficiency and cost.

The amount of the foaming agent added depends on the purpose.
Although not particularly limited, it is usually preferably 0.1 to 25 relative to 100 parts of the polycarbonate resin.
Parts, more preferably 0.3 to 18 parts. When the amount of the foaming agent added is less than 0.1 part, it is difficult to obtain a molded product having a sufficient expansion ratio, and when it exceeds 25 parts, it is difficult to obtain a foamed molded product having uniform cells.

Further, the amount of the foaming agent added may be varied depending on the amount of the (meth) acrylic acid ester-based polymer or polymer mixture added. In the case of 5 parts of a (meth) acrylic acid ester-based polymer or polymer mixture, 0.1 part to 5 parts of a foaming agent, and in the case of 10 parts of a (meth) acrylic acid ester-based polymer or polymer mixture, In the case of 0.5 parts to 10 parts of the foaming agent and 20 parts of the (meth) acrylic acid ester-based polymer or polymer mixture, it is preferable to add 1 part to 25 parts of the foaming agent.

To the foamable polycarbonate resin composition of the present invention, it is preferable to further add a filler in order to make the cells of the foamed molded product uniform and to improve the strength of the molded product.

Examples of the filler used in the present invention include talc, calcium carbonate, mica, wollastonite, clay and glass fiber. These may be used alone or in combination of two or more. Among them, talc, mica, wollastonite, and clay are preferable from the viewpoint of improving strength.

The amount of the filler added is 0.1 to 30 parts, preferably 0.3 to 20 parts, and more preferably 0.5 to 15 parts, relative to 100 parts of the polycarbonate resin. If the amount of the filler added is less than 0.1 part, a foamed molded product having uniform cells cannot be obtained, and it is difficult to obtain sufficient strength.
If it exceeds 30 parts, the viscosity during melting tends to be high, and the load during molding tends to be high.

The expandable polycarbonate resin composition of the present invention contains a compatibilizing agent for reducing a motor load in extrusion molding, a spreading agent for preventing classification of pellets and powders, a lubricant, if necessary. Other additives such as impact resistance enhancer, plasticizer and colorant may be added alone or in combination of two or more kinds.

The method for producing the expandable polycarbonate resin composition of the present invention is not particularly limited. For example, after mixing the polycarbonate resin, the (meth) acrylic acid ester-based polymer or polymer mixture, the thermal decomposition type foaming agent, the filler and other additives, a single-screw or twin-screw extruder at a suitable temperature. It can be produced by a method of melt-kneading with such a melt-kneader.

The method of molding the expandable polycarbonate resin composition of the present invention is not particularly limited, and a generally used molding method such as extrusion molding method can be applied.

[0049]

EXAMPLES The present invention will be described in more detail based on the following examples and comparative examples, but the present invention is not limited thereto.

The evaluation methods used in the examples and comparative examples are summarized below. (Measurement of Specific Viscosity of (Meth) Acrylate Ester Polymer) 0.1 g of a polymer sample was dissolved in 100 ml of chloroform and measured using a Uberroad type viscometer kept at a constant temperature in a water bath at 30 ° C. did. (Measurement of Foaming Ratio) The specific gravity of the obtained powder compound (polycarbonate resin composition non-foamed molded product) was measured, and then molded with a conical twin screw extruder CMT-45 manufactured by Cincinnati Miracron Co., Ltd. The specific gravity of the flat plate-shaped molded product (foamed molded product of the polycarbonate resin composition) was measured, and the expansion ratio was calculated by the following formula based on the measured value.

Expansion ratio = (specific gravity of non-foamed molded product of polycarbonate resin composition) / (specific gravity of foamed molded product of polycarbonate resin composition) The molding conditions are shown below. Molding conditions Molding temperature: C1 = 235 ° C., C2 = 235 ° C., C3 = 2
35 ° C., adapter = 200 ° C., die = 190 ° C. Screw rotation speed: 10 rpm Discharge rate: 15 kg / hour Die: 10 mm × 180 mm (Measurement of polymerization conversion rate) The polymerization conversion rate was calculated by the following formula.

Polymerization conversion rate (%) = {amount of polymerization product / amount of charged monomer} × 100 (measurement of latex average particle size) The latex obtained was measured using a U-2000 spectrophotometer manufactured by Hitachi Ltd. The average particle size was measured using light scattering at a wavelength of 546 nm. (Evaluation of surface property) Regarding the surface property of the obtained molded product,
The appearance was visually observed and evaluated according to the following criteria.

A: Surface roughness is hardly seen and the appearance is excellent.

B: Irregularities on the surface can be seen, but they are not so noticeable.

C: Many irregularities on the surface are seen, and the appearance is rather bad.

D: The surface is very uneven and the appearance is poor. (Measurement of compressive strength) Based on JIS K7220, 2
The compressive strength at 20% compression at 3 ° C. was measured. (Measurement of bending strength) 2 based on JIS K7221
Bending strength at 3 ° C was measured. (Measurement of heat distortion temperature) Based on JIS K7207,
The heat distortion temperature (hereinafter referred to as HDT) was measured under the condition that the bending stress was 18.5 kgf / cm ² . Example 1 0.7 part of sodium dioctyl sulfosuccinate previously dissolved in water was added as an emulsifier to an 8 liter reactor equipped with a stirrer, and the total amount of water was 200 parts including the amount of water contained in the auxiliary raw material added thereafter. Water was added. Oxygen in the space and water was removed by circulating nitrogen in the gas phase and the liquid phase in the reactor, and then the content was heated to 70 ° C. with stirring. Next, 60 parts of methyl methacrylate (hereinafter referred to as MMA) was added to the reactor.
A monomer mixture (a) consisting of 20 parts of butyl acrylate (hereinafter referred to as BA) was added all at once, and then 0.005 parts of potassium persulfate was added as an initiator, followed by stirring for 1 hour to carry out polymerization substantially. Completed. After that, MM
A monomer mixture (b) consisting of 6 parts A and 14 parts BA was added dropwise at a rate of about 30 parts per hour. After the dropping was completed, the content was kept at 70 ° C. for 90 minutes and then cooled to obtain a polymer latex, and the average particle size was measured. The results are shown in Table 1. The polymerization conversion rate at this time was 99.
It was 5%. The obtained polymer latex is salted out and coagulated with an aqueous calcium chloride solution, heat-treated at a temperature of up to 90 ° C., and then filtered using a centrifugal dehydrator, and the dehydrated cake of the obtained resin is in the same amount as the weight of the resin. It was washed with water and dried in a parallel-flow dryer at 50 ° C. for 15 hours to obtain a white powdery polymer sample (1). Further, the specific viscosity of the obtained polymer sample (1) was measured. The results are shown in Table 1.

Next, a polycarbonate resin (Japan GE
100 parts of Lexan FL900 manufactured by Plastics Co., Ltd., 10 parts of the polymer sample (1), 1.0 part of talc, 3.0 parts of sodium bicarbonate, a compatibilizer (Sumitomo Chemical Co., Ltd., Bondfast BF-7B) 1 0.0 parts, and 0.1 part of a spreading agent (Koshitani Kasei Kogyo Co., Ltd., Polybden) were mixed and mixed with a Henschel mixer to prepare a pellet compound, and a conical twin screw extruder CMT-4 manufactured by Cincinnati Miracron Co., Ltd.
The foamed molded product obtained by molding in No. 5 was evaluated for surface property and the expansion ratio was measured. The results are shown in Table 1.

Examples 2 to 7 and Comparative Examples 1 to 3 Polymer samples (2) to (10) were obtained in the same manner as in Example 1 except that the components shown in Table 1 were used according to the composition shown in Table 1. Each characteristic value was measured. Further, 10 parts of each of the obtained polymer samples (2) to (10) were used, blended with 100 parts of a polycarbonate resin, and a foamed molded product was obtained in the same manner as in Example 1, and the above evaluation was performed. It was set as Examples 2-7 and Comparative Examples 1-3. The results are shown in Table 1.

[0059]

[Table 1] From the results of Table 1, compositions of (meth) acrylic acid ester-based polymer samples (1) to (7) can be used to obtain compositions having good foamability, but methacrylic acid esters other than methyl methacrylate and acrylics Polymer samples (8) to (10) using the equivalent of the monomer mixture (a) in which the proportion of the acid ester and the vinyl monomer copolymerizable therewith are increased beyond the scope of the present invention are used. It was found that sufficient foamability could not be obtained in the case of presence.

Examples 8 to 12 and Comparative Examples 4 to 6 Polymer samples (11) to (18) were obtained in the same manner as in Example 1 according to the compositions shown in Table 2. The said evaluation was performed using the obtained polymer sample. The results are shown in Table 2.

[0061]

[Table 2] From the results in Table 2, when the composition of the monomer mixture (b) is within the range of the present invention as in the polymer samples (11) to (15), a composition having good foaming property is obtained. You can see that On the other hand, polymer samples (16) to (18) using a monomer mixture (b) equivalent having a composition outside the scope of the present invention
It can be seen that the foamability is reduced when is used.

Examples 13 to 17 and Comparative Examples 7 and 8 According to the compositions shown in Table 3, polymer samples (19) to (25) were obtained in the same manner as in Example 1.

The polymer samples obtained were evaluated as described above. The results are shown in Table 3.

[0064]

[Table 3] From the results in Table 3, as in the polymer samples (19) to (23), when the amount of the monomer mixture (a) was within the range of the present invention, a composition having good foamability was obtained. You can see that you can get it. On the other hand, when the polymer samples (24) and (25) in which the amount of the monomer mixture (a) is less than the range of the present invention is used, it is found that the foamability is not sufficient.

Examples 18 to 22 and Comparative Examples 9 and 10 Polymer samples (26) to (32) were obtained in the same manner as in Example 1 according to the compositions shown in Table 4.

The above evaluation was carried out for the obtained polymer sample. The results are shown in Table 4.

[0067]

[Table 4] From the results in Table 4, it can be seen that, when the polymer samples (26) to (30) having a specific viscosity within the range of the present invention were used, a composition having good foamability was obtained. On the other hand, when polymer samples (31) and (32) having a specific viscosity smaller or larger than the range of the present invention are used, it is understood that the foamability is not sufficient.

Examples 23 and 24 and Comparative Examples 11 and 12 In order to evaluate the difference in foamability when the number of blended parts of the polymer sample (28) used in Example 20 to the polycarbonate resin was changed, Molded product in the same manner as in Example 20 except that the polymer sample (28) used in 20 had 15 parts or 20 parts as shown in Table 5 instead of 10 parts with respect to 100 parts of the polycarbonate resin. And the foamability and surface property were evaluated. The results are shown in Table 5. However, in the case of Comparative Example 12, the non-uniformity of the composition increased, and it was not possible to obtain a molded product suitable for evaluating the foamability.

[0069]

[Table 5] From the results of Table 5, the composition in which the polymer sample (28) was blended in the range of the present invention showed good foamability, but as in Comparative Example 11, the blending number exceeded the range of the present invention. It can be seen that when the amount is reduced, sufficient foamability cannot be obtained. Examples 25 to 28 Molded articles were obtained in the same manner as in Example 20 except that the blending parts of the foaming agent were changed as shown in Table 6, and the foamability and surface property were evaluated. The results are shown in Table 6.

In the table, SBC represents sodium bicarbonate.

[0071]

[Table 6] Examples 29 to 34 and Comparative Examples 13 and 14 Molded articles were obtained in the same manner as in Example 20 except that the type and the number of parts of the filler were changed as shown in Table 7, and the foamability, surface properties, and compression strength were obtained. , Flexural strength, and HDT were evaluated. The results are shown in Table 7.

As the filler in the table, commercially available products as shown below were used. Talc: Fuji Talc, LMS-200 Mica: Yamaguchi Mica, A-21 Montmorillonite: Southern Clay, CLOISIT
E-25A

[0073]

[Table 7] From the results of Table 7, the composition containing various fillers within the range of the present invention has good foamability, surface property, compressive strength, flexural strength, and HDT, but as in Comparative Example 13. When the compounding number is reduced beyond the scope of the present invention and used,
Since uniform foam cells could not be obtained, the surface properties of the molded product were very poor, and a molded product suitable for the above evaluation could not be obtained. In addition, when the compounding amount was increased beyond the range of the present invention and used as in Comparative Example 14, the foam cells were severely broken, and a molded product suitable for the evaluation could not be obtained.

[0074]

The expandable polycarbonate resin composition of the present invention comprises a polycarbonate resin, a specific (meth) acrylic acid ester-based polymer, a filler and a foaming agent.
A foam molding with a high magnification of about 15 times can be obtained, and
It is possible to improve the deterioration of the surface properties and the strength of the molded product, which are caused by the improvement of the expansion ratio. Therefore, the manufacturing cost can be reduced by using the existing extruder, and the range of applications can be expanded.

Claims (4)

[Claims] 1. A unit weight of at least one selected from (A) 100 parts by weight of a polycarbonate resin, (B) 51 to 100% by weight of methyl methacrylate, and a methacrylic acid ester excluding methyl methacrylate and an acrylic acid ester. Monomer mixture (a) 5 consisting of 0 to 49% by weight of the polymer and 0 to 20% by weight of a vinyl-based monomer copolymerizable therewith
Presence of a latex of a polymer obtained by emulsion polymerization of 0 to 100 parts by weight and having a specific viscosity of 0.7 to 1.9 at 30 ° C. of a solution of 0.1 g of the polymer dissolved in 100 ml of chloroform. In the following, 51 to 100% by weight of at least one monomer selected from 0 to 49% by weight of methyl methacrylate, a methacrylic acid ester other than methyl methacrylate and an acrylic acid ester, and a vinyl copolymerizable therewith 1 to 50 parts by weight of a monomer mixture (b) consisting of 0 to 20% by weight of a system monomer [(a) and (b) combined
100 parts by weight] of the polymer or polymer mixture obtained by polymerizing 0.1 g of the polymer or polymer mixture in 100 ml.
(Meth) acrylic acid ester-based polymer or polymer mixture having a specific viscosity of 0.65 to 1.7 at 30 ° C. dissolved in chloroform of 0.5 to 3
A foamable polycarbonate resin composition containing 0 parts by weight, 0.1 to 30 parts by weight of a filler (C), and a foaming agent (D). 2. The expandable polycarbonate resin composition according to claim 1, wherein the filler (C) is talc, calcium carbonate, mica, wollastonite, clay or glass fiber. 3. The foaming agent (D) is a pyrolyzable foaming agent 0.1 to 10.
The expandable polycarbonate resin composition according to claim 1, which is 25 parts by weight. 4. A foamed molded article obtained by molding the expandable polycarbonate resin composition according to claim 1.