JP2011168696A - Aromatic polycarbonate resin composition for inorganic physical expansion molding, and foamed article thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aromatic polycarbonate resin composition for inorganic physical expansion molding capable of obtaining a fine foamed article having fine and uniform bubbles having, for example, an average cell diameter of 1,000 nm or less, and a foamed article thereof. <P>SOLUTION: The aromatic polycarbonate resin composition for inorganic physical expansion molding contains a graft copolymer comprising a polymer of an ethylenic unsaturated monomer (b) having an aromatic polycarbonate resin (a) as a main chain component and a (meth)acrylate or vinyl carboxylate as a side chain component. The polymer of the ethylenic unsaturated monomer (b) constituting the graft copolymer is a crosslinked product in which a number average dispersed particle diameter is 100-1,000 nm and standard deviation relative to the number average dispersed particle diameter is 5-20%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an aromatic polycarbonate resin composition for inorganic physical foam molding which can obtain a fine cell foam having a small cell diameter and uniform cells, and the foam.

  Conventionally, foams made of thermoplastic resins have been widely used in the fields of food containers, building materials, and the like due to their excellent heat insulation and shock absorption. As a typical manufacturing method of a thermoplastic resin foam, there are roughly two types, a chemical foaming method and a physical foaming method. The chemical foaming method is a method of foaming by mixing a thermoplastic resin with a low molecular weight chemical foaming agent such as an azo compound and heating to a temperature higher than the decomposition temperature of the chemical foaming agent. However, there are problems such as discoloration of the foam resulting from the decomposition residue of the chemical foaming agent and food hygiene problems, and the chemical foaming agent itself has a particle size distribution, so the thickness and density of the resulting foam There is a problem of non-uniformity.

  On the other hand, the physical foaming method is a method in which a low-boiling organic physical foaming agent such as butane is supplied to a thermoplastic resin and kneaded and then foamed by extruding into a low pressure region. This method has a feature that a wide range of foams from a low magnification to a high magnification can be easily produced by adjusting the amount of foaming agent added to the thermoplastic resin. However, since a foaming agent such as butane has flammability and toxicity, there is a problem that it must be cured until the concentration of the foaming agent remaining in the foamed molded product is lowered.

  In recent years, inorganic foam molding methods using inorganic physical foaming agents such as carbon dioxide and nitrogen have been proposed. Since these inorganic physical foaming agents are harmless and have no concern about environmental burden, they have a feature that a curing period after foam production is unnecessary. Moreover, since the foam diameter of the foam obtained by this method is finer (less than 10 μm) than the foam diameter of conventional foams (about 100 μm or more), it has the characteristics of excellent mechanical characteristics and optical characteristics. This is a foaming agent that is currently attracting attention. In particular, when an aromatic polycarbonate resin is used as a thermoplastic resin, it is widely used as an optical material especially around a liquid crystal display because of its high heat resistance and flame retardancy and transparency.

  However, when an aromatic polycarbonate resin is used, the molecular weight is low compared to other general-purpose amorphous thermoplastic resins, so the viscosity and melt tension at the time of melting are low. There was a problem that was easy to destroy. For this reason, when an aromatic polycarbonate resin is foamed, it is difficult to obtain a fine (10 μm or less) cell diameter, which is an advantage of an inorganic physical foam molding method, and low-density foam excellent in appearance and secondary workability. It has the disadvantage that it is difficult and difficult to obtain a body.

  As a method for solving this problem, as a resin composition for physical foam molding using carbon dioxide, a thermoplastic resin having low carbon dioxide solubility (for example, an aromatic polycarbonate resin) and an aromatic polycarbonate resin are not compatible. A method using a polymer alloy composed of a thermoplastic resin having high solubility of carbon dioxide (for example, polyethylene glycol) has been proposed (see, for example, Patent Document 1). By foaming this resin composition with carbon dioxide, bubbles are foamed only in a thermoplastic resin having a high solubility of carbon dioxide, so that a foam having a uniform and fine cell diameter can be obtained.

Further, a polymer alloy in which an amorphous thermoplastic resin (for example, polymethyl methacrylate resin) is controlled to have a dispersed particle diameter of 5 μm or less in an amorphous thermoplastic resin (for example, aromatic polycarbonate resin). As a material, a graft copolymer of an amorphous thermoplastic resin and an amorphous thermoplastic resin has been proposed (for example, see Patent Document 2). When this resin composition is foamed in a temperature range where the elastic modulus of the resin composition is 5.0 × 10 ⁸ Pa or less, foaming is performed only from the amorphous thermoplastic resin dispersed in advance. The foam diameter becomes as fine as 5 μm or less, and a foam having excellent lightweight and high strength, heat insulation and optical properties can be obtained.

  On the other hand, a method for obtaining a graft copolymer of a polymer of an aromatic polycarbonate resin and an ethylenically unsaturated monomer (for example, polymethyl methacrylate) has been proposed (for example, see Patent Document 3). That is, after impregnating an ethylenically unsaturated monomer (for example, methyl methacrylate) and an ethylenically unsaturated monomer having an organic peroxide group in an aromatic polycarbonate resin, the ethylenically unsaturated monomer This is a method in which a raw material obtained by radical polymerization of the mixture is radically polymerized under the condition that decomposition of the organic peroxide in the ethylenically unsaturated monomer having an organic peroxide group does not substantially occur.

JP 2005-271504 A JP 2008-303236 A Japanese Patent No. 3359724

  However, in the materials described in Patent Documents 1 to 3, because the dispersion particle size is different when the conditions (foaming machine and mold type, plasticizing conditions, thermal history, etc.) when foaming the material are changed, It was difficult to obtain a foam having a constantly stable cell diameter.

  Accordingly, an object of the present invention is to provide an inorganic physical foam capable of obtaining a fine cell foam having fine and uniform cells with an average cell diameter of 1000 nm or less, for example, without selecting conditions for foam molding. An object of the present invention is to provide an aromatic polycarbonate resin composition for molding and a foamed product thereof.

  In order to achieve the above object, the aromatic polycarbonate resin composition for inorganic physical foam molding according to the first invention has an aromatic polycarbonate resin (a) as a main chain component and a chemical formula (1) as a side chain component. An aromatic polycarbonate resin composition comprising a graft copolymer comprising a polymer of an ethylenically unsaturated monomer (b) which is a (meth) acrylic acid ester or a vinyl carboxylate represented by the following chemical formula (2) The polymer of the ethylenically unsaturated monomer (b) constituting the graft copolymer has a number average particle size of 100 to 1000 nm and a standard deviation of 5 to 20% with respect to the number average particle size. It is a crosslinked product.

（Ｒ^１は水素またはメチル基を示す。Ｒ^２はＣ_ｍＨ_ｍ＋１、ｍ＝１〜４の整数を示す。）

(R ¹ represents hydrogen or a methyl group. R ² represents an integer of C _m H _{m + 1} and m = 1 to 4.)

（Ｒ^３はＣ_ｎＨ_ｎ＋１、ｎ＝１〜４の整数を示す。）
第２の発明の無機系物理発泡成形用芳香族ポリカーボネート樹脂組成物は、第１の発明において、前記エチレン性不飽和単量体（ｂ）が、メタクリル酸メチルであることを特徴とする。

^{(R 3} represents an integer of _{C n H n + 1, n} = 1~4.)
The aromatic polycarbonate resin composition for inorganic physical foam molding of the second invention is characterized in that, in the first invention, the ethylenically unsaturated monomer (b) is methyl methacrylate.

  An aromatic polycarbonate resin composition for inorganic physical foam molding of a third invention is characterized in that, in the first or second invention, the ethylenically unsaturated monomer (b) is vinyl acetate. .

  The aromatic polycarbonate resin composition for inorganic physical foam molding according to a fourth aspect of the invention is the invention according to any one of the first to third aspects, wherein the graft copolymer is in the aromatic polycarbonate resin (a). An aromatic polycarbonate resin composition precursor obtained by impregnating and polymerizing an ethylenically unsaturated monomer (b), an ethylenically unsaturated monomer (c) having an organic peroxide group, and toluene (d) At a temperature 85 to 170 ° C. higher than the decomposition start temperature in the temperature raising process of 10 ° C./min using a scanning differential calorimeter of the ethylenically unsaturated monomer (c) having the organic peroxide group It is characterized by being melt kneaded.

  An aromatic polycarbonate resin composition for inorganic physical foam molding of a fifth invention is the fourth invention, wherein the ethylenically unsaturated monomer (c) having an organic peroxide group is t-butylperoxymethacryloyl. It is characterized by being oxyethyl carbonate or t-butyl peroxyallyl carbonate.

  The foam of the sixth invention is obtained by foaming the inorganic polycarbonate resin composition for inorganic physical foam molding according to any one of the first to fifth aspects with an inorganic physical foaming agent. And

According to the present invention, the following effects can be exhibited.
In the aromatic polycarbonate resin composition for inorganic physical foam molding in the first invention, the main chain component is an aromatic polycarbonate resin (a), and the side chain component is a specific formula represented by the chemical formula (1) or the chemical formula (2). A graft copolymer comprising a polymer of the ethylenically unsaturated monomer (b) is contained. Further, the polymer of the ethylenically unsaturated monomer (b) has a number average particle size of 100 to 1000 nm and a standard deviation of 5 to 20% with respect to the number average particle size is finely and uniformly dispersed cross-linked. Is the body.

  Therefore, the resin composition is subjected to foam molding as compared with the inorganic physical foam molding aromatic polycarbonate resin composition containing the graft copolymer in which the specific ethylenically unsaturated monomer (b) is not crosslinked. A fine cell foam having a fine and uniform cell diameter can be obtained without depending on the conditions.

  In the aromatic polycarbonate resin composition for inorganic physical foam molding in the second invention, the specific ethylenically unsaturated monomer (b) in the first invention is methyl methacrylate. For this reason, in addition to the effects of the first invention, methyl methacrylate is excellent in affinity with inorganic physical foaming agents such as carbon dioxide gas, and a fine cell foam having a finer and uniform cell diameter is obtained. It is done.

  In the aromatic polycarbonate resin composition for inorganic physical foam molding in the third invention, the specific ethylenically unsaturated monomer (b) in the first or second invention is vinyl acetate. For this reason, in addition to the effects of the first or second invention, the fine cell foam has a finer and more uniform cell diameter in which vinyl acetate is excellent in affinity with an inorganic physical foaming agent such as carbon dioxide gas. Is obtained.

  In the aromatic polycarbonate resin composition for inorganic physical foam molding according to the fourth invention, the graft copolymer comprises an ethylenically unsaturated monomer (b) and an organic peroxide in the aromatic polycarbonate resin (a). An aromatic polycarbonate resin composition precursor obtained by impregnating and polymerizing an ethylenically unsaturated monomer having a group (c) and toluene (d), and an ethylenically unsaturated monomer having an organic peroxide group It is formed by melt-kneading at a temperature 85 to 170 ° C. higher than the decomposition start temperature in the temperature raising process of 10 ° C./min using the scanning differential calorimeter (c).

  Therefore, a method not containing an ethylenically unsaturated monomer (c) having an organic peroxide group, or a melt kneading temperature is higher than the decomposition start temperature of the ethylenically unsaturated monomer having an organic peroxide group. Compared with an inorganic polycarbonate resin composition for physical foam molding obtained by a method of less than 85 ° C. or more than 170 ° C., it is fine and uniform without depending on the conditions for foam molding of the resin composition. A fine cell foam having an appropriate cell diameter is obtained.

  In the aromatic polycarbonate resin composition for inorganic physical foam molding in the fifth invention, the ethylenically unsaturated monomer (c) having an organic peroxide group in the fourth invention is t-butylperoxymethacryloyloxyethyl. Carbonate or t-butyl peroxyallyl carbonate. For this reason, in addition to the effect of 4th invention, while the graft reaction and crosslinking reaction of ethylenically unsaturated monomer (b) advance smoothly, the fine bubble foam which has a fine and uniform bubble diameter Is obtained.

  The foam of the aromatic polycarbonate resin composition for inorganic physical foam molding in the sixth invention is obtained by foaming the polycarbonate resin composition obtained by the first to fifth inventions with an inorganic physical foaming agent. Therefore, the foam has fine and uniform air bubbles, and quality such as lightness, mechanical properties, heat resistance, heat insulation, optical properties, etc., compared with the foam obtained by the conventional method. Can exhibit good and stable performance.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described in detail.
In the aromatic polycarbonate resin composition for inorganic physical foam molding of the present embodiment, the main chain component is an aromatic polycarbonate resin (a), and the side chain component is a (meth) acrylic ester represented by the following chemical formula (1) or It contains a graft copolymer made of a polymer of ethylenically unsaturated monomer (b) which is vinyl carboxylate represented by chemical formula (2). The polymer of the ethylenically unsaturated monomer (b) constituting the graft copolymer has a number average particle size of 100 to 1000 nm and a standard deviation of 5 to 20% with respect to the number average particle size. It is a crosslinked product dispersed in the resin (a).

（Ｒ^１は水素またはメチル基を示す。Ｒ^２はＣ_ｍＨ_ｍ＋１、ｍ＝１〜４の整数を示す。）

(R ¹ represents hydrogen or a methyl group. R ² represents an integer of C _m H _{m + 1} and m = 1 to 4.)

（Ｒ^３はＣ_ｎＨ_ｎ＋１、ｎ＝１〜４の整数を示す。）
前記グラフト共重合体の主鎖成分である芳香族ポリカーボネート樹脂（ａ）の製法は、従来の芳香族ポリカーボネート樹脂と同様の製法、即ち界面重合法、ピリジン法、クロロホルメート法等の溶液法で製造されるものと、エステル交換法の溶融法で製造されるものである。芳香族ポリカーボネート樹脂（ａ）の粘度平均分子量は、好ましくは２，０００〜１００，０００、より好ましくは５，０００〜５０，０００、特に好ましくは６，０００〜３０，０００である。溶液法で製造される場合には、反応後の芳香族ポリカーボネート樹脂溶媒から芳香族ポリカーボネート樹脂を固形化して回収する方法として、芳香族ポリカーボネート樹脂溶液に貧溶媒を添加して沈殿化する方法、芳香族ポリカーボネート樹脂溶液から溶媒を留去して濃縮し、粉体状とする方法、芳香族ポリカーボネート樹脂溶液に貧溶媒を添加し、加熱下の温水中に該混合物を添加し、温水中に懸濁させて溶媒および貧溶媒を留去して固形化して水スラリー液を生成させつつ湿式粉砕機に循環し粉砕する方法等の種々の方法がある。本発明においては芳香族ポリカーボネート樹脂の水懸濁液として、芳香族ポリカーボネート樹脂の水スラリー液をそのまま用いるのが合理的であり好ましい。

^{(R 3} represents an integer of _{C n H n + 1, n} = 1~4.)
The production method of the aromatic polycarbonate resin (a), which is the main chain component of the graft copolymer, is the same production method as that of the conventional aromatic polycarbonate resin, that is, a solution method such as an interfacial polymerization method, a pyridine method, or a chloroformate method. Those manufactured and those manufactured by the transesterification melting method. The viscosity average molecular weight of the aromatic polycarbonate resin (a) is preferably 2,000 to 100,000, more preferably 5,000 to 50,000, and particularly preferably 6,000 to 30,000. When produced by a solution method, as a method of solidifying and recovering the aromatic polycarbonate resin from the aromatic polycarbonate resin solvent after the reaction, a method of adding a poor solvent to the aromatic polycarbonate resin solution and precipitating, By distilling off the solvent from the aromatic polycarbonate resin solution and concentrating it to a powder, adding a poor solvent to the aromatic polycarbonate resin solution, adding the mixture to warm water under heating, and suspending in the warm water There are various methods such as a method of distilling off the solvent and the poor solvent and solidifying the solution to form a water slurry, and circulating and pulverizing the wet pulverizer. In the present invention, it is reasonable and preferable to use the aromatic polycarbonate resin water slurry as it is as the aqueous suspension of the aromatic polycarbonate resin.

  Specific examples of preferred dihydric phenol compounds used for the production of the aromatic polycarbonate resin (a) include bis (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) ether, and bis (4-hydroxy). Phenyl) sulfone, bis (4-hydroxyphenyl) sulfoxide, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl) ketone, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis ( 4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 2,2-bis (4-hydroxy-3,5-dibromophenyl) Propane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) pro 2,2-bis (4-hydroxy-3-bromophenyl) propane, 2,2-bis (4-hydroxy-3-chlorophenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethyl) Phenyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, bis (4-hydroxyphenyl) diphenylmethane are exemplified.

  There is no problem even if an aromatic polycarbonate resin having a reactive unsaturated terminal group is used as the aromatic polycarbonate resin (a). The above-mentioned process for producing an aromatic polycarbonate resin having an unsaturated end group is performed by using a conventional functional aromatic compound except that a monofunctional compound having a double bond is used as a molecular weight regulator or a terminal terminator, or a conventional terminal terminator. It is produced by a production method similar to that of the group polycarbonate resin, that is, a solution method such as an interfacial polymerization method, a pyridine method, or a chloroformate method. Monofunctional compounds having a double bond for introducing an unsaturated end group include acrylic acid, methacrylic acid, vinyl acetic acid, 2-pentenoic acid, 3-pentenoic acid, 5-hexenoic acid, 9-decenoic acid, Unsaturated carboxylic acids such as 9-undecenoic acid, acrylic acid chlorides, methacrylic acid chlorides, sorbic acid chlorides, acid chlorides or chloroformates such as allyl alcohol chloroformate, isopropenyl phenol chloroformate or human loxystyrene chloroformate , Phenols having an unsaturated group such as isopropenylphenol, hydroxystyrene, hydroxyphenylmaleimide, hydroxybenzoic acid allyl ester or hydroxybenzoic acid methylallyl ester. These compounds may be used in combination with conventional terminal terminators, and are usually in the range of 1 to 25 mol%, preferably 1.5 to 10 mol%, relative to 1 mol of the dihydric phenol compound described above. Used in.

  The aromatic polycarbonate resin (a) is produced by using the above-mentioned components as essential components, but the branching agent is preferably 0.01 to 3 mol%, particularly preferably 0.1 to 3 mol% with respect to the dihydric phenol compound. It can also be used in the range of 1 to 1.0 mol% to make a branched polycarbonate resin. Such branching agents include phloroglysin, 2,6-dimethyl-2,4,6-tri (4-hydroxyphenyl) heptene-3, 4,6-dimethyl-2,4,6-tri (4 -Hydroxyphenyl) heptene-2, 1,3,5-tri (2-hydroxyphenyl) benzene, 1,1,1-tri- (4-hydroxyphenyl) ethane, 2,6-bis (2-hydroxy-5) -Methylbenzyl) -4-methylphenol, polyhydroxy compounds exemplified by α, α ′, α ″ -tri (4-hydroxyphenyl) -1,3,5-triisopropylbenzene, and 3,3- Bis (4-hydroxyaryl) oxindole (= Isatin bisphenol), 5-Chlorisantine bisphenol, 5,7-bromoisatin bisphenol, 5-bromo Such as satin bisphenol is exemplified.

  The shape of the aromatic polycarbonate resin (a) is preferably granular or pelletized with a particle size of about 0.1 to 5 mm. If the particle size is excessively large, not only is it difficult to disperse in the suspension, but there is also a disadvantage that the impregnation time of the ethylenically unsaturated monomer (b) becomes long. Moreover, it is more preferable when impregnating it is porous.

Since the aromatic polycarbonate resin (a) has fluidity that can be processed by a conventional molding machine, specifically, the melt volume rate (MVR) at 300 ° C. and 1.2 kg load is 0.2 to 40 cm ³ / it is preferably 10min, still more preferably 0.5~20cm ³ / 10min. The melt volume rate is insufficient fluidity of the aromatic polycarbonate resin in the case of less than 0.2 cm ³ / 10min, the molding becomes difficult. Meanwhile a melt flow rate of the mechanical properties of the injection molded article is deteriorated in the case of more than 40 cm ³ / 10min.

  The polymer of the specific ethylenically unsaturated monomer (b), which is a side chain component of the graft copolymer, is excellent in affinity with carbon dioxide gas, which is a representative inorganic physical foaming agent. The specific ethylenically unsaturated monomer (b) used as a raw material of the polymer is a monomer represented by the chemical formula (1) or the chemical formula (2).

  Examples of the ethylenically unsaturated monomer (b) represented by the chemical formula (1) include methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylic acid-n-propyl, and methacrylic acid-n-propyl. , Isopropyl acrylate, isopropyl methacrylate, acrylic acid-n-butyl, methacrylic acid-n-butyl, acrylic acid-sec-butyl, methacrylic acid-sec-butyl, acrylic acid-t-butyl, methacrylic acid-t-butyl Is mentioned. Among these, preferably methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, acrylic acid-n-propyl, methacrylic acid-n-propyl, acrylic acid-n-butyl or methacrylic acid-n-butyl More preferably, it is methyl methacrylate. These ethylenically unsaturated monomers can be used alone or in admixture of two or more.

  Examples of the ethylenically unsaturated monomer (b) represented by the chemical formula (2) include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl valerate, and vinyl pivalate. Among these, vinyl acetate, vinyl propionate or vinyl butyrate is preferable, and vinyl acetate is most preferable. These ethylenically unsaturated monomers can be used alone or in admixture of two or more.

  The polymer of the ethylenically unsaturated monomer (b) constituting the side chain component of the graft copolymer needs to be a crosslinked product. When the polymer is not a cross-linked product, depending on the conditions when foam-molding the obtained aromatic polycarbonate resin composition, the dispersion particle size of the polymer of the ethylenically unsaturated monomer pair (b) and the uniformity of the dispersed particles are The fine bubble foam which changes and has a fine and uniform bubble diameter and is stable over time cannot be obtained.

  Whether the polymer of the specific ethylenically unsaturated monomer (b) is a crosslinked product is determined by placing the aromatic polycarbonate resin composition in a cylindrical filter paper and using a soluble solvent (for example, xylene) under reflux. When Soxhlet extraction is performed, the percentage obtained by dividing the mass of the ethylenically unsaturated monomer (b) polymer present in the extract by the mass of the charged ethylenically unsaturated monomer (b) polymer is It can be confirmed by being 5% or less.

  The crosslinked body has a number average particle diameter of 100 to 1000 nm, and its number average particle diameter is excellent in physical properties such as mechanical properties, heat resistance, heat insulation, and optical properties, and a stable quality product is obtained. It is necessary that the standard deviation with respect to is distributed by 5 to 20%. When the number average particle diameter exceeds 1000 nm, a fine cell foam having an average cell diameter of 1000 nm or less cannot be obtained by foam molding. On the other hand, when the number average particle diameter is less than 100 nm, the dispersed particle diameter of the crosslinked product becomes too fine, and the preparation thereof is difficult. On the other hand, when the standard deviation exceeds 20%, the particle diameter of the dispersed particles of the crosslinked product varies, and a desired fine cell foam cannot be obtained after foam molding. On the other hand, when the standard deviation is less than 5%, it is difficult to produce the crosslinked product.

The number average particle diameter of the dispersed particles of the crosslinked product and the standard deviation measurement method for the number average particle size are obtained by measuring an ultrathin section having a thickness of 50 to 100 nm with an ultramicrotome from the obtained aromatic polycarbonate resin composition (molded product). It is prepared and measured from a dispersed particle image of a polymer of ethylenically unsaturated monomer (b) obtained by observation with a transmission electron microscope (TEM). The number average particle size is determined by counting the number of independent particles that can be confirmed in the field of view within a range of 100 μm ² (10 μm length, 10 μm width) or more, and measuring at least a total of 100 particle sizes with a graduated ruler. It means the number average particle size calculated by averaging. However, when the particle image obtained by TEM observation is not circular, the diameter of the circle when the area occupied by the particle is calculated and then replaced with a circle having the same area is referred to as the particle diameter. The standard deviation with respect to the number average particle size indicating the uniformity of the dispersed particle size of the crosslinked product is calculated by calculating the standard deviation (σ) of each particle size obtained for measuring the number average particle size. It calculated | required by correcting per particle size.

  The mass ratio of the aromatic polycarbonate resin resin (a), which is the main chain component of the graft copolymer, to the crosslinked product of the ethylenically unsaturated monomer (b), which is the side chain component, is 95/5 to 5-5. The range is / 95. When the mass of the aromatic polycarbonate resin (a) of the graft copolymer exceeds 95% by mass, foaming does not occur. On the other hand, when the mass of the aromatic polycarbonate resin (a) is less than 5% by mass, when the graft copolymer is further mixed with the aromatic polycarbonate resin (a), uniform dispersibility is not exhibited. Does not become a cellular foam.

  Here, it is possible to further add an aromatic polycarbonate resin (a) to the graft copolymer in the aromatic polycarbonate resin composition. The amount of the aromatic polycarbonate resin (a) added is the polymer of the aromatic polycarbonate resin and the ethylenically unsaturated monomer (b) in the aromatic polycarbonate resin composition regardless of whether or not the graft copolymerization is performed. The mass ratio is not particularly limited as long as it is in the range of 95/5 to 55/45. In this case, a polymer alloy having a sea-island structure in which the aromatic polycarbonate resin is the sea and the ethylenically unsaturated monomer (b) polymer is an island is formed. When the aromatic polycarbonate resin in the aromatic polycarbonate resin composition exceeds 95% by mass, foaming of the aromatic polycarbonate resin composition hardly occurs. On the other hand, when the aromatic polycarbonate resin in the aromatic polycarbonate resin composition is less than 45% by mass, the polymer of the ethylenically unsaturated monomer (b) forming the island of the polymer alloy having the sea-island structure In order to form, it becomes difficult for a bubble to unite and to become a fine bubble foam.

Next, the manufacturing method of the said graft copolymer is demonstrated.
The graft copolymer comprises an ethylenically unsaturated monomer (b), an ethylenically unsaturated monomer (c) having an organic peroxide group, and toluene (d) in the aromatic polycarbonate resin (a). The aromatic polycarbonate resin composition precursor obtained by copolymerizing the mixture is melt-kneaded at a temperature 85 to 170 ° C. higher than the decomposition start temperature of the ethylenically unsaturated monomer (c) having the organic peroxide group. Obtained by the method.

  Conventionally known methods are adopted as the method for producing the graft copolymer, and among them, the method shown below is the most preferable method. This method consists of the following two steps. That is, an impregnation polymerization step for obtaining an aromatic polycarbonate resin composition precursor and a grafting step for obtaining an aromatic polycarbonate resin composition containing a graft copolymer are provided. The impregnation polymerization step is a mixture of an ethylenically unsaturated monomer (b), an ethylenically unsaturated monomer (c) having an organic peroxide group and toluene (d) in the aromatic polycarbonate resin (a). Is impregnated with a radical polymerization initiator and then an aromatic polycarbonate resin composition precursor is obtained. The grafting step is a step of obtaining an aromatic polycarbonate resin composition containing a graft copolymer by melt-kneading an aromatic polycarbonate resin composition precursor.

  In the impregnation polymerization step, a radical polymerization initiator is added to a mixture of an ethylenically unsaturated monomer (b), an ethylenically unsaturated monomer (c) having an organic peroxide group, and toluene (d), and an organic If it is the method of heating on the conditions which decomposition | disassembly of the organic peroxide group of the ethylenically unsaturated monomer (c) which has a peroxide group does not occur substantially, it will not specifically limit.

  A well-known thing is used as an ethylenically unsaturated monomer (c) which has an organic peroxide group. Specifically, t-butylperoxyacryloyloxyethyl carbonate (decomposition start temperature 135 ° C.), t-amyl peroxyacryloyloxyethyl carbonate (decomposition start temperature 133 ° C.), t-hexyl peroxyacryloyloxyethyl carbonate (decomposition start temperature 130). ° C), t-butylperoxymethacryloyloxyethyl carbonate (decomposition start temperature 136 ° C), t-amyl peroxymethacryloyloxyethyl carbonate (decomposition start temperature 134 ° C), t-hexylperoxymethacryloyloxyethyl carbonate (decomposition start temperature 131 ° C) Conjugated ethylenically unsaturated monomers such as t-butyl peroxyallyl carbonate (decomposition start temperature 130 ° C.), t-amyl peroxyallyl carbonate (decomposition start temperature 1) 8 ° C.), a non-conjugated ethylenically unsaturated monomers such as t- hexyl peroxy allyl carbonate (decomposition temperature 125 ° C.) and the like. Among these, t-butylperoxymethacryloyloxyethyl carbonate (decomposition start temperature 136 ° C.) is used as the conjugated ethylenically unsaturated monomer, and t-butylperoxyallyl carbonate (decomposed) is used as the nonconjugated ethylenically unsaturated monomer. More preferred is a starting temperature of 130 ° C. You may use these individually or in mixture of 2 or more types.

  The amount of the ethylenically unsaturated monomer (c) having an organic peroxide group is such that the specific ethylenically unsaturated monomer (b) and the ethylenically unsaturated monomer having an organic peroxide group are used. Preferably it is 0.1-5 mass parts with respect to 100 mass parts of mixtures with a body (c), More preferably, it is 0.5-3 mass parts. When the amount used is less than 0.1 parts by mass, the aromatic polycarbonate resin composition precursor has a small amount of active oxygen, and a sufficient graft copolymer cannot be obtained. On the other hand, when the amount used exceeds 5 parts by mass, a large amount of radicals are generated in the grafting step, so that the degree of crosslinking of the crosslinked polymer of the ethylenically unsaturated monomer (b) increases, and the aromatic polycarbonate The appearance of the molded body formed from the resin composition is deteriorated, making it difficult to foam the molded body.

  The toluene (d) is not only a solvent for uniformly impregnating the ethylenically unsaturated monomer (b) in the impregnation polymerization step into the aromatic polycarbonate resin (a), but also in the impregnation polymerization step. Solvent for uniformly reacting the molecular weight regulator in polymerizing the ethylenically unsaturated monomer (b) and the crosslinked product of the polymer of the ethylenically unsaturated monomer (b) in the grafting step Is an important substance that works as.

  0.5-10 mass parts is preferable with respect to 100 mass parts of ethylenically unsaturated monomers (b), and, as for the addition amount of toluene (d), 0.7-2 mass parts is more preferable. When the amount of toluene (d) added is less than 0.5 parts by mass, the polymerization of the ethylenically unsaturated monomer (b) tends to be non-uniform in the impregnation polymerization step, and non-uniform in the subsequent grafting step. Since the reaction occurs, the dispersed particle size of the polymer of the ethylenically unsaturated monomer (b), that is, the crosslinked product becomes non-uniform. On the other hand, when the amount of toluene (d) added exceeds 10 parts by mass, the amount of toluene remaining in the resulting aromatic polycarbonate resin composition increases, and the appearance during molding deteriorates.

  The radical polymerization initiator is a compound having a decomposition temperature for obtaining a half-life of 10 hours (hereinafter referred to as a 10-hour half-life temperature) of preferably 40 to 90 ° C, more preferably 50 to 75 ° C. This is because, as described above, the polymerization in the impregnation polymerization process must be performed under the condition that the ethylenically unsaturated monomer (c) having an organic peroxide group to be used is not decomposed. Since the 10-hour half-life temperature of the ethylenically unsaturated monomer (c) having an organic peroxide group is 90 to 110 ° C, the polymerization temperature is preferably 90 ° C or lower.

  When the 10-hour half-life temperature of the radical polymerization initiator exceeds 90 ° C., the polymerization temperature increases, and the ethylenically unsaturated monomer (c) having an organic peroxide group may be decomposed during the polymerization. is there. On the other hand, when the 10-hour half-life temperature of the radical polymerization initiator is less than 40 ° C., radicals are generated in the process in which the aromatic polycarbonate resin (a) is impregnated with the radical polymerization initiator. As a result, the composition of the precursor of the aromatic polycarbonate resin composition to be produced tends to be non-uniform, and a non-uniform reaction occurs in the subsequent grafting step. The dispersed particle size of the body becomes non-uniform. Here, the 10-hour half-life temperature is a temperature at which the decomposition rate of the radical polymerization initiator is 50% when 0.1 mole of the radical polymerization initiator is added to 1 liter of benzene and 10 hours have passed at a certain temperature. Say.

  Examples of such radical polymerization initiators include: Di-n-propyl peroxydicarbonate (10-hour half-life temperature 40.3 ° C), diisopropyl peroxydicarbonate (10-hour half-life temperature 40.5 ° C), di (2-ethylhexyl) peroxydicarbonate (10-hour half-life) Temperature 43.6 ° C), t-hexylperoxyneodecanate (10-hour half-life temperature 44.7 ° C), t-butylperoxyneodecanate (10-hour half-life temperature 46.5 ° C), t-hexylperoxypione Valate (10-hour half-life temperature 53.2 ° C.), t-butyl peroxypivalate (10-hour half-life temperature 55.0 ° C.), di (3,3,5-trimethylhexanoyl) peroxide (10-hour half-life temperature) 59.5 ° C), dilauroyl peroxide (10 hour half-life temperature 62.0 ° C), t-hexylperoxy-2 Examples include ethyl hexanoate (10-hour half-life temperature 69.9 ° C), t-butylperoxy-2-ethylhexanoate (10-hour half-life temperature 72.5 ° C), dibenzoyl peroxide (74 ° C), and the like. . You may use these individually or in mixture of 2 or more types.

  The amount of the radical polymerization initiator used is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 3 parts by mass with respect to 100 parts by mass in total of the ethylenically unsaturated monomer mixture. When the amount of the radical polymerization initiator used is less than 0.01 parts by mass, the mixture of the ethylenically unsaturated monomer (b) and the ethylenically unsaturated monomer (c) having an organic peroxide group Polymerization is not performed completely and a good molded product cannot be obtained. On the other hand, when the amount of the radical polymerization initiator used exceeds 5 parts by mass, the mechanical strength of the resulting molded product of the aromatic polycarbonate resin composition is reduced by the low molecular weight due to radical decomposition of the aromatic polycarbonate resin (a) during the polymerization. Decreases.

  The weight average molecular weight (Mw) of the copolymer of the mixture of the ethylenically unsaturated monomer (b) and the ethylenically unsaturated monomer (c) having an organic peroxide group is a differential refractive index detector. It is represented by a polystyrene conversion value by gel permeation chromatography (also referred to as gel permeation chromatography, also referred to as GPC). The weight average molecular weight is preferably 50,000 to 3,000,000, more preferably 100,000 to 2,000,000. When the weight average molecular weight is less than 50,000, in order to obtain a crosslinked product of the polymer of ethylenically unsaturated monomer (b), ethylene having ethylenically unsaturated monomer (b) and an organic peroxide group The ethylenically unsaturated monomer (c) having an organic peroxide group in the mixture with the polymerizable unsaturated monomer (c) exceeds 10% by mass. Therefore, a lot of radicals are generated in the grafting step, and the mechanical strength of the resulting molded product of the aromatic polycarbonate resin composition is lowered due to the low molecular weight by radical decomposition of the aromatic polycarbonate resin (a). On the other hand, when the weight average molecular weight exceeds 3 million, melt kneading in the subsequent grafting step becomes difficult.

  The method of the impregnation polymerization step is performed by a commonly used aqueous suspension polymerization method. Accordingly, the aromatic polycarbonate resin (a) and a radical polymerization initiator prepared separately from the above are used as the ethylenically unsaturated monomer (b) and the ethylenically unsaturated monomer (c) having an organic peroxide group. A solution dissolved in a mixture of toluene and toluene (d) is stirred and dispersed in water in the presence of a suspending agent that can be used for aqueous suspension polymerization. As the suspending agent, for example, water-soluble polymer (partially saponified) polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, or the like, or a poorly water-soluble inorganic substance such as calcium phosphate, magnesium oxide or the like is used. .

  At this time, the impregnation of the solution into the aromatic polycarbonate resin (a) is preferably performed at as high a temperature as possible. However, if the radical polymerization initiator decomposes and starts polymerization during impregnation, the composition of the precursor of the aromatic polycarbonate resin composition to be formed tends to be non-uniform, and a non-uniform reaction occurs in the subsequent grafting step. Therefore, the dispersed particle size of the crosslinked polymer of the ethylenically unsaturated monomer (b) is not uniform. Therefore, generally, it is preferable to carry out at a temperature lower by 5 ° C. or more than the 10-hour half-life temperature of the radical polymerization initiator used.

  A mixture of a free ethylenically unsaturated monomer (b), an ethylenically unsaturated monomer (c) having an organic peroxide group, and toluene (d) and a radical polymerization initiator are mixed with an aromatic polycarbonate resin. It is preferable to impregnate (a) until the impregnation is less than 50% by mass of the initial addition amount, and preferably less than 20% by mass. If this amount is 50% by mass or more, the composition of the precursor of the aromatic polycarbonate resin composition to be produced tends to be non-uniform, and a non-uniform reaction occurs in the subsequent grafting step. The dispersed particle size of the crosslinked polymer of (b) becomes non-uniform.

  The total amount of the mixture of the free ethylenically unsaturated monomer (b) and the ethylenically unsaturated monomer having an organic peroxide group (c) and the radical polymerization initiator is an arbitrary amount of the aqueous suspension. And is quickly filtered using a wire mesh of about 300 mesh to separate the aromatic polycarbonate resin (a) and the liquid phase, and the radical polymerization starts with the ethylenically unsaturated monomer mixture in the liquid phase. The amount of the agent is measured and calculated.

  The polymerization for obtaining the precursor of the aromatic polycarbonate resin composition is usually performed at a temperature of 30 to 110 ° C. This is to prevent decomposition of the ethylenically unsaturated monomer (c) having an organic peroxide group during polymerization as much as possible. When this temperature exceeds 110 ° C., when the polymerization time is 5 hours or longer, the ethylenically unsaturated monomer (c) having an organic peroxide group is decomposed and radicals of the aromatic polycarbonate resin (a) are produced. By lowering the molecular weight by decomposition, the mechanical strength of the resulting molded product of the aromatic polycarbonate resin composition is lowered. In general, the polymerization time is suitably 2 to 20 hours.

In the impregnation polymerization step, a chain transfer agent as a molecular weight regulator or a polyfunctional ethylenically unsaturated monomer can be used in combination so as not to impair workability and physical properties.
In the grafting step, the aromatic polycarbonate resin composition precursor described above is melt-kneaded at a temperature 85 to 170 ° C. higher than the decomposition start temperature of the ethylenically unsaturated monomer (c) having an organic peroxide group. Done. By this grafting step, a molded article of the aromatic polycarbonate resin composition is obtained. The organic peroxide group in the ethylenically unsaturated monomer having an organic peroxide group contributes to the graft reaction with the aromatic polycarbonate resin (a) that becomes the main chain of the graft copolymer by melt kneading. ing. In addition, when the graft reaction temperature is 85 to 170 ° C. higher than the decomposition start temperature of the ethylenically unsaturated monomer (c) having an organic peroxide group, not only the graft reaction but also the graft copolymer It contributes also to the crosslinking reaction of the polymer of the ethylenically unsaturated monomer (b) which becomes the side chain of

  Here, when the difference between the melt kneading temperature and the decomposition start temperature of the ethylenically unsaturated monomer (c) having an organic peroxide group is less than 85 ° C., the ethylenically unsaturated monomer (b) Since the above polymer does not become a crosslinked product, a fine cell foam having a fine and uniform cell diameter cannot be obtained depending on the conditions for foam molding of the obtained aromatic polycarbonate resin composition. On the other hand, when the difference between the melt kneading temperature and the decomposition start temperature of the ethylenically unsaturated monomer (c) having an organic peroxide group exceeds 170 ° C., radicals are instantaneously generated during the melt kneading. It will be deactivated. Therefore, the graft reaction and the cross-linking reaction do not occur, and a fine cell foam having a fine and uniform cell diameter cannot be obtained depending on the conditions at the time of foam molding the resulting aromatic polycarbonate resin composition.

  The melt kneading time in the grafting step is preferably 30 to 300 seconds, and most preferably 60 to 120 seconds. If it is less than 30 seconds, uniform kneading is difficult, and if it exceeds 300 seconds, the crosslinked product of the polymer of the aromatic polycarbonate resin (a) or the ethylenically unsaturated monomer (b) is decomposed by kneading and becomes ethylenically unsaturated. The number average particle size of the polymer of the monomer (b) is 100 to 1000 nm, and the standard deviation with respect to the number average particle size cannot be dispersed with 5 to 20%.

  The melt-kneading apparatus is not particularly limited as long as it is a known one. For example, various extruders such as a single screw extruder and a twin screw extruder, and melt kneaders such as a Banbury mixer, a Brabender, a plastograph, a heat roll, and a kneader are used. Can be mentioned. In addition, the aromatic polycarbonate resin composition includes an ultraviolet absorber, an antioxidant, a crystal nucleating agent, an antistatic agent, a flame retardant, a filler, a pigment, a colorant, a release agent, a lubricant, and an antibacterial agent as necessary. Etc. can be blended within a range not impairing the characteristics of the aromatic polycarbonate resin composition.

  Next, the foam is impregnated with an inorganic physical foaming agent pressurized against the above-mentioned aromatic polycarbonate resin composition molded body, and the foaming agent is saturated in the molded body and then foamed. There is no particular limitation as long as it can be obtained by the method. The foaming method is not particularly limited, and any one of a reduced pressure foaming method in which foaming is performed by rapid decompression and a temperature rising foaming method in which foaming is performed by raising the temperature can be employed. However, the foaming temperature is preferably not more than the temperature (240 ° C.) at which the aromatic polycarbonate resin (a) flows.

  Examples of the inorganic physical foaming agent include carbon dioxide, nitrogen, helium, argon, nitrous oxide, ethylene, ethane, tetrafluoroethylene, perfluoroethane, tetrafluoromethane, etc. Among these, carbon dioxide and nitrogen are included. More preferred is carbon dioxide.

  The foaming ratio when foaming the molded article of the aromatic polycarbonate resin composition is preferably about 1.1 to 5 times. When the expansion ratio is less than 1.1 times, the obtained foam cannot fully exhibit the function as a foam, and when it exceeds 5 times, the expansion ratio becomes too high and the strength of the foam Is not preferable.

  In order to make the obtained foam into a fine cell foam having fine and uniform cells, the number average cell diameter is preferably 1000 nm or less, and more preferably 50 to 800 nm. When the number average bubble diameter exceeds 1000 nm, the bubbles do not become fine, and the function as a fine bubble foam cannot be expressed. Moreover, it is preferable that the standard deviation with respect to the number average bubble diameter is 5 to 25%. When the standard deviation exceeds 25%, the uniformity of the bubbles cannot be obtained, and the function of the fine bubble foam deteriorates.

  By using the above-mentioned polycarbonate resin composition, it is possible to obtain a fine cell foam having fine and uniform cells. Therefore, the fine cell foam has light weight, mechanical properties, heat insulation properties, optical properties, and the like. Excellent physical properties.

  If necessary, the foam may be subjected to surface treatment such as corona treatment, printing, coating, and vapor deposition as long as the characteristics are not impaired. The foam obtained in this way is a reflective material used for liquid crystal display devices, lighting fixtures, lighting signs, etc., application to the material field requiring low dielectric constant, high-strength porous material, heat insulating material, cushioning material, etc. It can be effectively used for various purposes.

Hereinafter, the embodiment will be described more specifically with reference to examples and comparative examples. Various physical property values in each example were measured by the following methods.
(1) Melt volume rate (MVR) of aromatic polycarbonate resin
Melt flow measuring device according to JISK7210 [melt flow indexer, Toyo Seiki Seisakusho Co., TYPEC-5059D] at a cylinder temperature of 300 ° C., measured melt volume rate at a load 1.2 kg ^(cm 3 / 10min) did.
(2) Weight average molecular weight (Mw) of polymer of ethylenically unsaturated monomer (b) in aromatic polycarbonate resin precursor
Using a gel permeation chromatography apparatus [GPC, manufactured by Shimadzu Corporation] equipped with a differential refractive index detector, the eluent was tetrahydrofuran (hereinafter referred to as THF), the column temperature was 40 ° C., and the standard polystyrene conversion was used.
(3) Dispersibility of copolymer cross-linked product of ethylenically unsaturated monomer (b) in aromatic polycarbonate resin composition and molded article Ethylenically unsaturated monomer in aromatic polycarbonate resin composition ( b) Number average particle diameter of crosslinked copolymer and measurement of standard deviation with respect to number average particle diameter: From the obtained molded product of the aromatic polycarbonate resin composition, an ultramicrotome [Ultracut UCT, manufactured by Leica Co., Ltd.] An ultra-thin section having a thickness of 50 to 100 nm was prepared. The obtained ultrathin slice was observed and photographed for the dispersion state of the ethylenically unsaturated monomer copolymer using a transmission electron microscope (TEM) (JEM-1600EX, manufactured by JEOL Ltd.).

Using a plurality of the obtained TEM photographs, the number of independent particles that can be confirmed in the visual field was counted in a range of 100 μm ² (10 μm in length, 10 μm in width) or more. Further, in the TEM photograph, a plurality of arbitrary photographs were selected so that the total number of particles was 100 or more, the particle diameter was measured with a ruler with a scale, and the number average particle diameter was calculated. Furthermore, the standard deviation (σ) of each particle size was calculated and corrected per number average particle size to obtain the standard deviation with respect to the number average particle size.
(4) Confirmation of crosslinked polymer of ethylenically unsaturated monomer (b) in aromatic polycarbonate resin composition Polymer of ethylenically unsaturated monomer (b) in aromatic polycarbonate resin composition Quantitative determination of uncrosslinked product: Aromatic polycarbonate resin composition 0.5 g was accurately weighed and cylindrical filter paper [manufactured by Advantech Co., Ltd., No. 86R] and extracted with xylene using a Soxhlet extractor for 24 hours. The obtained extract was added to 10 times the amount of THF solvent to precipitate the aromatic polycarbonate resin (a), and the filtered solution was dried under reduced pressure by an evaporator. By measuring the mass and dividing by the total mass of the ethylenically unsaturated monomer (b) used and the ethylenically unsaturated monomer (c) having an organic peroxide group, the aromatic polycarbonate resin composition The uncrosslinked product (%) of the polymer of the ethylenically unsaturated monomer (b) in the product was calculated. In addition, the thing whose this number is 5% or less is judged as a crosslinked body, and the thing over 5% is judged as an uncrosslinked body.
(5) Confirmation of graft copolymer of aromatic polycarbonate resin (a) and crosslinked product of polymer of ethylenically unsaturated monomer (b) Weigh accurately 0.5 g of aromatic polycarbonate resin composition. Take a cylindrical filter paper [Advantech Co., Ltd., No. 86R] and extracted with xylene using a Soxhlet extractor for 24 hours. After drying the polymer present in the cylindrical filter paper, the aromatic polycarbonate resin was quantified by pyrolysis gas chromatography, and the content of the aromatic polycarbonate resin (a) in the graft copolymer was calculated.
(6) Dispersion state of foamed bubbles of aromatic polycarbonate resin composition foam Number average cell diameter in aromatic polycarbonate resin composition foam and measurement of standard deviation with respect to number average cell diameter: obtained aromatic polycarbonate resin composition The product foam was immersed in liquid nitrogen and freeze fractured. The obtained fracture surface was vapor-deposited in gold, and the dispersion state of the foamed bubble diameter was observed and photographed using a scanning electron microscope (SEM) [S-3000N, manufactured by Hitachi High-Tech Co., Ltd.]. Using a plurality of the obtained SEM photographs, the number of independent bubble particles that can be confirmed in the visual field was counted in a range of 400 μm ² (vertical 20 μm, horizontal 20 μm) or more. Further, in the SEM photograph, a plurality of arbitrary photographs were selected so that the total number of bubble particles was 100 or more, the particle diameter was measured with a ruler with a scale, and the number average bubble diameter was calculated. Furthermore, the standard deviation of each bubble diameter was calculated and corrected per number average particle diameter to obtain the standard deviation with respect to the number average bubble diameter.
(7) Foaming ratio of the aromatic polycarbonate resin composition foam Using the solid specific gravity meter [SD-200L, Alpha Mirage Co., Ltd.], the obtained aromatic polycarbonate resin composition foam (0.5 g) Specific gravity (d ₂ ) was measured. The specific gravity (d ₁ ) of the aromatic polycarbonate resin composition before foaming was also measured by the same method, and the foaming ratio was calculated by the following formula.

Foaming ratio (times) = d ₁ / d ₂
The raw materials used in the examples and comparative examples are as follows.
Aromatic polycarbonate resin (a): Aromatic polycarbonate resin made from 2,2-bis (4-hydroxyphenyl) propane, manufactured by Idemitsu Kosan Co., Ltd., trade name “Taflon A2600”, viscosity average molecular weight 26,000 , melt volume rate ^(MVR) = 6.0cm 3 / 10min
Ethylenically unsaturated monomer (b): Methyl methacrylate (MMA) manufactured by Mitsubishi Gas Chemical Co., Ltd., Butyl Acrylate (BA) manufactured by Nippon Shokubai Co., Ltd. VAc), vinyl pivalate (VPv) manufactured by Nihon Vinegar Poval Co.
Ethylenically unsaturated monomer having an organic peroxide group (c): t-butylperoxy-2-methacryloyloxyethyl carbonate manufactured by NOF Corporation, trade name “Peromer MEC (MEC)”, NOF Corporation ) T-Butylperoxy-allyl monocarbonate, trade name "Peromer AC (AC)"
Toluene (d): Special grade reagent manufactured by Wako Pure Chemical Industries, Ltd. Radical polymerization initiator: t-Butylperoxy-2-ethylhexanoate (TBEH) manufactured by NOF Corporation, trade name “Perbutyl O”
(Example 1-1)
700 parts by mass of an aromatic polycarbonate resin was placed in a stainless separable flask having an internal volume of 5000 ml, 2500 ml of pure water and 2.5 parts by mass of polyvinyl alcohol as a suspending agent were added. Separately, as an ethylenically unsaturated monomer having an organic peroxide group in 300 parts by mass of methyl methacrylate (MMA), 6 parts by mass of t-butylperoxy-2-methacryloyloxyethyl carbonate (MEC), 6 parts by mass of toluene and a radical As a polymerization initiator, 1.5 parts by mass of t-butylperoxy-2-ethylhexanoate (TBEH) was dissolved, and this solution was put into the separable flask and stirred. The aromatic polycarbonate resin was then impregnated with MMA, MEC and TBEH by maintaining o at 40 ° C. and stirring for about 6 hours. The temperature was then raised to 70 ° C. and maintained at that temperature for 5 hours to complete the polymerization, washed with water and dried to obtain a grafted precursor. The graft precursor MMA and MEC copolymer was extracted with chloroform and dried, and the weight average molecular weight (Mw) was measured.

  Subsequently, this aromatic polycarbonate resin composition precursor is extruded at 250 ° C. with a single screw extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd.) and grafted to cause an aromatic polycarbonate resin composition containing a graft copolymer. Got. The dispersion form of the MMA polymer (PMMA) in this resin composition was measured by TEM and shown in Table 1. Table 1 shows the graft efficiency of PMMA and the average swelling particle diameter in toluene from the insoluble matter obtained by Soxhlet extraction of this graft copolymer with o-dichlorobenzene at 160 ° C. for 1 hour.

The obtained graft copolymer was cut into a size of 100 mm in length and 100 mm in width, placed in a metal spacer having a length of 100 mm, a width of 100 mm, and a thickness of 0.25 mm, and 10 MPa using a hot press set at 230 ° C. The molded body was obtained by holding at 25 ° C. for 1 minute at a pressure of 5 minutes. The dispersion form of PMMA in this molded body was measured by TEM and shown in Table 1.
(Example 1-2)
In Example 1-1, Example 1 was changed except that the aromatic polycarbonate resin was changed to 950 parts by mass, MMA to 50 parts by mass, MEC to 1 part by mass, toluene to 1 part by mass, and THEH to 0.25 parts by mass. An aromatic polycarbonate resin composition and a molded body were obtained in the same manner as in -1. These were evaluated by the same method, and the results are shown in Table 1.
(Example 1-3)
In Example 1-1, Example 1 was changed except that the aromatic polycarbonate resin was changed to 550 parts by mass, MMA to 450 parts by mass, MEC to 9 parts by mass, toluene to 9 parts by mass, and TBEH to 2.25 parts by mass. An aromatic polycarbonate resin composition and a molded body were obtained in the same manner as in -1. These were evaluated by the same method, and the results are shown in Table 1.
(Example 1-4)
In Example 1-1, an aromatic polycarbonate resin composition and a molded body were obtained in the same manner as in Example 1-1 except that MMA was changed to butyl acrylate (BA). These were evaluated by the same method, and the results are shown in Table 1.
(Example 1-5)
In Example 1-1, an aromatic polycarbonate resin composition, a molded product and a foam were obtained in the same manner as in Example 1-1 except that MMA was changed to vinyl acetate (VAc) and MEC was changed to AC. . These were evaluated by the same method, and the results are shown in Table 1.
(Example 1-6)
In Example 1-1, an aromatic polycarbonate resin composition, a molded product, and a foam are obtained in the same manner as in Example 1-1 except that MMA is changed to vinyl pivalate (VPv) and MEC is changed to AC. It was. These were evaluated by the same method, and the results are shown in Table 1.
(Examples 2-1 to 2-6)
The molded product of the aromatic polycarbonate resin composition obtained in Examples 1-1 to 1-6 was put into an autoclave whose temperature was adjusted to 40 ° C., and pressurized to 10 MPa with carbon dioxide (carbon dioxide). Carbon dioxide was impregnated for 6 hours. Thereafter, the autoclave leak valve is fully opened, the pressure in the autoclave is released at a depressurization rate of 0.5 MPa / sec, and the removed molded body is immediately immersed in an oil bath set at 80 ° C. for 1 minute. Thereafter, it was immersed in water at 25 ° C. to obtain a foam. The foam foam dispersion and foaming ratio of the obtained foam were measured and shown in Table 1.

（実施例１−７）
実施例１−１において、ＭＥＣ６質量部をＭＥＣ０．３質量部に変更した以外は実施例１−１と同様の方法で、芳香族ポリカーボネート樹脂組成物および成形体を得た。これらを同様の方法で評価し、その結果を表２に示した。
（実施例１−８）
実施例１−１において、ＭＥＣ６質量部をＭＥＣ１５質量部に変更した以外は実施例１−１と同様の方法で、芳香族ポリカーボネート樹脂組成物および成形体を得た。これらを同様の方法で評価し、その結果を表２に示した。
（実施例１−９）
実施例１−１において、トルエン６質量部をトルエン１．５質量部に変更した以外は実施例１−１と同様の方法で、芳香族ポリカーボネート樹脂組成物および成形体を得た。これらを同様の方法で評価し、その結果を表２に示した。
（比較例１−１）
実施例１−１において、ＭＥＣ６質量部をＭＥＣ０質量部に、トルエン６質量部をトルエン０質量部に変更した以外は実施例１−１と同様の方法で、芳香族ポリカーボネート樹脂組成物および成形体を得た。これらを同様の方法で評価し、その結果を表２に示した。
（比較例１−２）
実施例１−１において、トルエン６質量部をトルエン０質量部に、グラフト化反応温度を２２０℃に変更した以外は実施例１−１と同様の方法で、芳香族ポリカーボネート樹脂組成物および成形体を得た。これらを同様の方法で評価し、その結果を表２に示した。
（比較例１−３）
実施例１−１において、トルエン６質量部をトルエン０質量部に、グラフト化反応温度を３１０℃に変更した以外は実施例１−１と同様の方法で、芳香族ポリカーボネート樹脂組成物および成形体を得た。これらを同様の方法で評価し、その結果を表２に示した。
（実施例２−７〜２−９、比較例２−１〜２−３）
実施例１−７〜１−９および比較例１−１〜１−３で得られた芳香族ポリカーボネート樹脂組成物の成形体を４０℃に温度調節されたオートクレーブに投入し、炭酸ガス（二酸化炭素）で１０ＭＰａに加圧し、成形体に二酸化炭素を６時間含浸させた。その後オートクレーブのリークバルブを全開放し、減圧速度０.５ＭＰａ／ｓｅｃでオートクレーブ内の圧力を開放し、取り出した成形体を瞬時にあらかじめ８０℃に設定されたオイルバス中で１分間浸漬し、その後２５℃の水に浸漬して発泡体を得た。得られた発泡体の発泡気泡の分散形態および発泡倍率を測定し、表２に示した。

(Example 1-7)
In Example 1-1, an aromatic polycarbonate resin composition and a molded body were obtained in the same manner as in Example 1-1 except that 6 parts by mass of MEC was changed to 0.3 parts by mass of MEC. These were evaluated by the same method, and the results are shown in Table 2.
(Example 1-8)
In Example 1-1, an aromatic polycarbonate resin composition and a molded body were obtained in the same manner as in Example 1-1 except that 6 parts by mass of MEC was changed to 15 parts by mass of MEC. These were evaluated by the same method, and the results are shown in Table 2.
(Example 1-9)
In Example 1-1, an aromatic polycarbonate resin composition and a molded body were obtained in the same manner as in Example 1-1 except that 6 parts by mass of toluene was changed to 1.5 parts by mass of toluene. These were evaluated by the same method, and the results are shown in Table 2.
(Comparative Example 1-1)
In Example 1-1, an aromatic polycarbonate resin composition and a molded body were obtained in the same manner as in Example 1-1, except that 6 parts by mass of MEC was changed to 0 parts by mass of MEC and 6 parts by mass of toluene were changed to 0 parts by mass of toluene. Got. These were evaluated by the same method, and the results are shown in Table 2.
(Comparative Example 1-2)
In Example 1-1, an aromatic polycarbonate resin composition and a molded product were obtained in the same manner as in Example 1-1 except that 6 parts by mass of toluene was changed to 0 parts by mass of toluene and the grafting reaction temperature was changed to 220 ° C. Got. These were evaluated by the same method, and the results are shown in Table 2.
(Comparative Example 1-3)
In Example 1-1, an aromatic polycarbonate resin composition and a molded product were obtained in the same manner as in Example 1-1 except that 6 parts by mass of toluene was changed to 0 parts by mass of toluene and the grafting reaction temperature was changed to 310 ° C. Got. These were evaluated by the same method, and the results are shown in Table 2.
(Examples 2-7 to 2-9, Comparative Examples 2-1 to 2-3)
The molded article of the aromatic polycarbonate resin composition obtained in Examples 1-7 to 1-9 and Comparative Examples 1-1 to 1-3 was put into an autoclave whose temperature was adjusted to 40 ° C., and carbon dioxide gas (carbon dioxide ) To 10 MPa, and the compact was impregnated with carbon dioxide for 6 hours. After that, fully open the leak valve of the autoclave, release the pressure in the autoclave at a depressurization rate of 0.5 MPa / sec, and immediately immerse the removed molded body in an oil bath set at 80 ° C. for 1 minute. A foam was obtained by immersion in water at 25 ° C. The foam foam dispersion and foaming ratio of the obtained foam were measured and shown in Table 2.

表２に示したように、比較例１−１では有機過酸化物基を有するエチレン性不飽和単量体（ｃ）およびトルエン（ｄ）を含有しない芳香族ポリカーボネート樹脂組成物を用いたため、芳香族ポリカーボネート樹脂（ａ）とエチレン性不飽和単量体（ｂ）の重合体とからなるグラフト共重合体が存在しなかった。従って、グラフト化工程後に得られた芳香族ポリカーボネート樹脂組成物中に架橋体が存在せず、その成形体におけるエチレン性不飽和単量体（ｂ）の重合体の分散粒径が大きくかつ不均一になるため、成形時の熱履歴によって分散粒径が異なる。さらに比較例２−１では、比較例１−１の芳香族ポリカーボネート樹脂組成物の成形体から得られる発泡体は、発泡気泡径が非常に大きくかつ不均一となる。

As shown in Table 2, in Comparative Example 1-1, the aromatic polycarbonate resin composition containing no organic peroxide group (c) and toluene (d) was used. There was no graft copolymer consisting of a polymer of the aromatic polycarbonate resin (a) and the ethylenically unsaturated monomer (b). Accordingly, there is no crosslinked product in the aromatic polycarbonate resin composition obtained after the grafting step, and the dispersion particle size of the polymer of the ethylenically unsaturated monomer (b) in the molded product is large and uneven. Therefore, the dispersed particle size varies depending on the thermal history during molding. Furthermore, in Comparative Example 2-1, the foam obtained from the molded article of the aromatic polycarbonate resin composition of Comparative Example 1-1 has a very large foam cell diameter and is non-uniform.

  On the other hand, as shown in Table 1 and Table 2, in Examples 1-1 to 1-9, the ethylenically unsaturated monomer (c) having an organic peroxide group was changed to an ethylenically unsaturated monomer. (B) 0.1-5 parts by mass with respect to 100 parts by mass, 0.5-10 parts by mass of toluene (d) with respect to 100 parts by mass of the ethylenically unsaturated monomer (b), and grafting During the conversion step, the mixture was melt-kneaded at a temperature 85 ° C. to 170 ° C. higher than the decomposition start temperature of the ethylenically unsaturated monomer (c) having an organic peroxide group. For this reason, Comparative Example 1-2 melt-kneaded at a temperature lower than 85 ° C. or higher than 170 ° C. from the decomposition start temperature of the ethylenically unsaturated monomer (c) having an organic peroxide group during the grafting step and Compared with the aromatic polycarbonate resin composition of 1-3, the polymer of the ethylenically unsaturated monomer (b) is cross-linked and the aromatic polycarbonate resin (a) is grafted, so that the heat during molding The dispersion particle diameter of the crosslinked polymer of the ethylenically unsaturated monomer (b) due to the history is small and uniform. From this, the foam obtained by foaming the molded article of the aromatic polycarbonate resin composition of Examples 2-1 to 2-9 was the molded article of the aromatic polycarbonate resin composition of Comparative Examples 2-2 and 2-3. It was revealed that a uniform fine foam having a small foam cell diameter can be obtained as compared with a foam obtained by foaming. Therefore, the foam of the molded body obtained from the aromatic polycarbonate resin composition can be a useful material for obtaining a fine foam molded article excellent in optical characteristics such as mechanical characteristics and reflection characteristics.

Claims (6)

Ethylenically unsaturated monomer whose main chain component is aromatic polycarbonate resin (a) and whose side chain component is (meth) acrylic acid ester represented by the following chemical formula (1) or vinyl carboxylate represented by the following chemical formula (2) In an aromatic polycarbonate resin composition containing a graft copolymer comprising a polymer of the body (b),
The polymer of the ethylenically unsaturated monomer (b) constituting the graft copolymer has a number average particle size of 100 to 1000 nm and a cross-linked having a standard deviation of 5 to 20% with respect to the number average particle size. An aromatic polycarbonate resin composition for inorganic physical foam molding, characterized by being a body.

(R ¹ represents hydrogen or a methyl group. R ² represents an integer of C _m H _{m + 1} and m = 1 to 4.)

^{(R 3} represents an integer of _{C n H n + 1, n} = 1~4.) The aromatic polycarbonate resin composition for inorganic physical foam molding according to claim 1, wherein the ethylenically unsaturated monomer (b) is methyl methacrylate. The aromatic polycarbonate resin composition for inorganic physical foam molding according to claim 1 or 2, wherein the ethylenically unsaturated monomer (b) is vinyl acetate. The graft copolymer comprises an ethylenically unsaturated monomer (b), an ethylenically unsaturated monomer (c) having an organic peroxide group, and toluene (d) in the aromatic polycarbonate resin (a). An aromatic polycarbonate resin composition precursor obtained by impregnating and polymerizing an ethylenic unsaturated monomer (c) having an organic peroxide group was heated at a rate of 10 ° C./min using a scanning differential calorimeter. The inorganic physical foam molding according to any one of claims 1 to 3, wherein the material is melt-kneaded at a temperature 85 to 170 ° C higher than a decomposition start temperature in the temperature process. Aromatic polycarbonate resin composition. The inorganic system according to claim 4, wherein the ethylenically unsaturated monomer (c) having an organic peroxide group is t-butylperoxymethacryloyloxyethyl carbonate or t-butylperoxyallyl carbonate. An aromatic polycarbonate resin composition for physical foam molding. A foamed product obtained by foaming the aromatic polycarbonate resin composition for inorganic physical foam molding according to any one of claims 1 to 5 with an inorganic physical foaming agent.