JP2002080683A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic polycarbonate resin composition which has been improved in moldability (flowability, etc.), without detriment to the excellent mechanical characteristics (impact resistance, etc.), inherent in a polycarbonate resin and thus exhibits an excellent balance between these two characteristics. SOLUTION: This resin composition contains (B) a polycarbonate and (A) a polymer which does not substantially contain a gel and is obtained by polymerizing (a-4) an aromatic vinyl monomer in the presence of a polymer obtained by polymerizing (a-1) 15-100 mass% alkyl (meth)acrylate having a 2-20C alkyl group, (a2) 85-0 mass% aromatic vinyl monomer, and (a-3) a monomer having at least two unsaturated groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polycarbonate-based thermoplastic resin composition having excellent fluidity and impact strength.

[0002]

2. Description of the Related Art Polycarbonate has excellent mechanical properties such as impact strength, and is therefore used in various fields such as home appliances and housing materials for OA equipment.

[0003] Polycarbonate has the disadvantage of low fluidity and poor moldability. Further, when the molecular weight of the polycarbonate itself is reduced in order to improve the fluidity, the impact strength is reduced. Further, it is common practice to mix a styrene-butadiene-acrylonitrile copolymer in order to improve the fluidity. However, in order to obtain an effective fluidity, the amount of the styrene-butadiene-acrylonitrile copolymer increases and the impact strength decreases. It is the current situation.

[0004] Therefore, in order to improve the balance between flowability and impact strength of polycarbonate, addition of various vinyl polymers has been attempted in the past. When roughly classified, there are attempts to improve the flowability of a high-molecular-weight polycarbonate or the like having a high impact strength and low flowability, and attempts to improve the impact strength of a low-molecular-weight polycarbonate having a high flowability and low impact strength.

JP-A-56-143239, JP-A-4-65461 and JP-A-1-268761 state that the addition of a polymer containing an alkyl acrylate rubber improves the impact strength of polycarbonate. Have been. However, the resin composition thus obtained has insufficient levels of fluidity and impact strength.

Japanese Patent Application Laid-Open No. 62-138514 discloses that the addition of a polymer comprising an aromatic vinyl monomer and methyl methacrylate improves the flowability of polycarbonate. However, the resin composition thus obtained has low impact strength.

JP-A-5-140435 describes that the addition of a low molecular weight polymer comprising an aromatic vinyl monomer and an alkyl acrylate improves the flowability of polycarbonate. However, since this low molecular weight polymer contains a large amount of soft components, it is tacky and has poor handling properties such as easy blocking, and when the thickness of the test piece is large, its impact strength is reduced.

[0008] Japanese Patent Application Laid-Open No. 1-268761 describes that the addition of a high-molecular-weight alkyl methacrylate polymer is effective in preventing dripping during extrusion molding of polycarbonate. However, this addition has no effect on improving the fluidity.

Japanese Patent Application Laid-Open No. 11-181197 discloses that a polycarbonate containing a low-molecular-weight aromatic vinyl polymer having a solubility parameter of more than 9.3 and less than 11.5 is added to fluidity, heat resistance and transparency. It is described as having excellent odor and smoke. However, the resin composition thus obtained has low impact resistance.

As described above, the addition of various vinyl polymers has been attempted in the prior art, but none of them has been sufficient in improving the balance between the flowability and impact strength of polycarbonate.

[0011]

That is, according to the present invention, the moldability (flowability, etc.) of polycarbonate is improved without impairing the excellent mechanical properties (impact strength, etc.) inherent to polycarbonate. An object of the present invention is to provide a polycarbonate-based thermoplastic resin composition having an excellent balance.

[0012]

Means for Solving the Problems The inventors of the present invention have made intensive studies to achieve the above-mentioned object, and have found that it is very effective to add a specific polymer obtained by two-stage polymerization to polycarbonate. As a result, the present invention has been completed.

That is, the present invention relates to an alkyl (meth) acrylate having an alkyl group having 2 to 20 carbon atoms (a-
1) 15 to 100% by mass of an aromatic vinyl monomer (a-
2) Polymerization of aromatic vinyl monomer (a-4) in the presence of a polymer obtained by polymerizing 85 to 0% by mass and monomer (a-3) having two or more unsaturated groups A substantially gel-free polymer (A) and a polycarbonate (B)
And a thermoplastic resin composition containing:

In the present invention, "(meth) acrylate" means "acrylate and / or methacrylate".

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below.

The alkyl (meth) acrylate (a-1) used in the present invention has an alkyl group having 2 to 20 carbon atoms, and the alkyl group may be linear or branched. Specific examples thereof include ethyl (meth) acrylate, butyl (meth) acrylate, 2-methylbutyl (meth) acrylate, 3-methylbutyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, and octyl (meth). Examples include acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, and eicosyl (meth) acrylate. One or more of these can be used.

Considering the fluidity and cost of the resin composition, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate ) Acrylates are preferred. Of these, ethyl (meth) acrylate, butyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate are more preferred.

The aromatic vinyl monomer (a-
Specific examples of 2) include styrene, α-methylstyrene, p-methylstyrene, α-methyl-p-methylstyrene, p-methoxystyrene, o-methoxystyrene,
Examples thereof include 2,4-dimethylstyrene, chlorostyrene, and bromostyrene. These can be used alone or in combination of two or more. Considering the fluidity and cost of the resin composition, styrene, α-methylstyrene and chlorostyrene are preferred.

Specific examples of the monomer (a-3) having two or more unsaturated groups used in the present invention include allyl (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, ethylene glycol di (meth) acrylate. ) Acrylate, propylene glycol di (meth) acrylate,
1,3-butylene glycol di (meth) acrylate,
1,4-butylene glycol di (meth) acrylate can be mentioned, but in consideration of the fluidity of the resin composition, two kinds having different reactivity such as allyl (meth) acrylate, triallyl cyanurate, triallyl isocyanurate, etc. Monomers having the above unsaturated groups are preferred. Triallyl cyanurate and triallyl isocyanurate have three allyl groups, but the reactivity of the first reacting allyl group is different from the reactivity of the second and third reacting allyl groups.

The monomers (a-1), (a-2) and (a)
When polymerizing -3), α such as ethylene or propylene is used.
Esters of vinyl alcohol such as vinyl acetate; compounds containing epoxy groups such as vinyl glycidyl ether and allyl glycidyl ether; dicarboxylic anhydrides such as maleic anhydride; amino groups, hydroxy groups,
Vinyl monomers containing functional groups such as mercapto groups, carboxylic acid groups, carboxylic anhydrides, dicarboxylic acids, halogen groups, and carbonyl halides; copolymerizable with (meth) acrylic acid, methyl (meth) acrylate, etc. One or two or more of the components can be used in combination so as to be 50% by mass or less of the entire polymerization components.

The aromatic vinyl monomer (a-
As 3), the same as (a-2) can be mentioned.

When polymerizing the monomer (a-4), (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate,
Alkyl (meth) acrylates such as 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate and stearyl (meth) acrylate; α-olefins such as ethylene and propylene; esters of vinyl alcohol such as vinyl acetate ;
Compounds containing an epoxy group such as glycidyl (meth) acrylate, vinyl glycidyl ether, allyl glycidyl ether; dicarboxylic anhydrides such as maleic anhydride; amino groups, hydroxy groups, mercapto groups, carboxylic acid groups, carboxylic anhydrides, Dicarboxylic acid, halogen group,
One or two or more copolymerizable components such as a vinyl monomer having a functional group such as a carbonyl halide can be used in combination so as to be 50% by mass or less of the entire polymerization components.

The polymer (A) used in the present invention is obtained by two-stage polymerization. In the first stage polymerization, an alkyl (meth) acrylate (a-1), an aromatic vinyl monomer (a-2) and a monomer (a-3) having two or more unsaturated groups are polymerized. I do.

In the second stage polymerization, an aromatic vinyl monomer (a-a) is added in the presence of the polymer obtained in the first stage polymerization.
4) is polymerized.

Alkyl (meth) in the first stage polymerization
Acrylate (a-1), aromatic vinyl monomer (a-
The ratio of (2) is (a-1) 15 to 100% by mass, (a-)
2) 85 to 0% by mass, considering the impact strength of the resin composition, (a-1) 25 to 100% by mass, (a-2) 7
5 to 0% by mass is preferable, and considering the appearance of the resin composition, (a-1) 25 to 95% by mass and (a-2) 75 to 75%
5 mass% is more preferable, (a-1) 25 to 85 mass%, and (a-2) 75 to 15 mass% is still more preferable.

The polymer (A) contains substantially no gel. Here, the gel is a polymer or a polymer particle having a three-dimensional network structure. As a method of confirming that the polymer (A) does not contain a gel, for example, if there is a liquid that dissolves the polymer (A), it can be said that the polymer (A) does not substantially contain a gel.

The amount of the monomer (a-3) having two or more unsaturated groups in the first-stage polymerization is as follows:
Is a range substantially not containing a gel, and is preferably 0.001 to 10 parts by mass based on a total of 100 parts by mass of (a-1) and (a-2). When (a-3) was not contained, the appearance of the molded resin composition was poor, and (a-3)
If the amount of -3) is too large or the reactivity is high, a gel is formed in the polymer, and the fluidity of the resin composition is reduced. The use of a chain transfer agent in the first-stage polymerization is preferable since the formation of a gel is suppressed, and the use amount thereof is 0.00
1 to 10 parts by mass is preferred.

The ratio of the first-stage polymer and the aromatic vinyl monomer (a-4) in the second-stage polymerization may be appropriately determined as desired, and is not particularly limited in the present invention. . However, based on the amount of each monomer used, (a-
1) to 90% by mass in total of 1) and (a-2);
4) 99 to 10% by mass is preferred, (a-1) and (a-2) in total of 5 to 60% by mass, and (a-4) 95 to 4% by mass.
0 mass% is more preferable. Aromatic vinyl monomer (a-
When the proportion of 4) is appropriately increased, the tackiness of the polymer (A) can be suppressed, blocking can be favorably prevented, and handleability is improved. When the proportion of the aromatic vinyl monomer (a-4) is appropriately reduced, the impact strength of the resin composition is further improved.

The weight-average molecular weight of the polymer after the first polymerization is 3,000 in consideration of the moldability of the resin composition.
３０300,000 is preferable, and 3,000-50,000 is more preferable.
The weight average molecular weight of the polymer (A) after the second stage polymerization is preferably 3000 to 1,000,000, and more preferably 3000 to 600,000. The molecular structure of the polymer (A) is not particularly limited as long as it does not substantially contain a gel. For example, a linear type, a comb type, a branched type, a star type, a cascade type and the like can be mentioned.

The method of the two-stage polymerization for obtaining the polymer (A) is not particularly limited. For example, in systems such as bulk, solution, emulsification and suspension, radical polymerization, anion polymerization, cationic polymerization and the like can be used. Various known polymerization methods can be used. In addition, various kinds of conventionally known polymerization additives such as a polymerization initiator, a polymerization catalyst, a chain transfer agent, a molecular weight regulator, an organic solvent, a dispersion medium, an emulsifier, and a dispersant can be used during the polymerization.

Examples of the radical polymerization initiator include peroxides such as tert-butyl hydroperoxide and cumene hydroperoxide; azo initiators such as azobisisobutyronitrile; oxidizing agents and reducing agents. Redox initiators in combination. Specific examples of the redox initiator include a sulfoxylate initiator obtained by combining ferrous sulfate, disodium ethylenediaminetetraacetate, Rongalid, and hydroperoxide.

Examples of the emulsifier include a nonionic emulsifier, an anionic emulsifier, a cationic emulsifier, and a zwitterionic emulsifier. Specific examples of the nonionic emulsifier include polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, dialkylphenoxypoly (ethyleneoxy) ethanol, polyvinyl alcohol, polyacrylic acid, and alkyl cellulose. Specific examples of anionic emulsifiers include fatty acid salts, higher alcohol sulfates, liquid fatty oil sulfates, sulfates of aliphatic amines and aliphatic amides, fatty alcohol phosphates, and sulfonates of dibasic fatty acid esters. Salts, fatty acid amide sulfonates, alkyl allyl sulfonates, and naphthalene sulfonates of formalin condensate are exemplified. Specific examples of the cationic emulsifier include aliphatic amine salts, quaternary ammonium salts, and alkylpyridinium salts. Specific examples of the amphoteric ion emulsifier include alkyl betaine.

Examples of the chain transfer agent include n-octyl mercaptan, tert-dodecyl mercaptan and the like.

When the first-stage polymerization is carried out by, for example, emulsion radical polymerization, water, an emulsifier, an alkyl (meth) acrylate (a-1), an aromatic vinyl monomer (a
-2), a monomer (a-3) having two or more unsaturated groups,
A polymerization catalyst may be added to a mixture comprising a polymerization initiator, a chain transfer agent, and the like, if necessary, and the monomer may be polymerized at a high temperature. Then, the aromatic vinyl monomer (a-4) is supplied into the polymerization system after the emulsion radical polymerization, and the first-stage polymerization is performed, whereby the polymer (A) can be obtained. it can.

In the first-stage polymerization and the second-stage polymerization, the method of supplying each monomer is not particularly limited, and the monomers may be supplied at once or may be supplied little by little. .

According to the emulsion polymerization, a latex of the polymer (A) is obtained, and the polymer (A) can be separated and recovered by pouring the latex into an aqueous solution of a coagulant. As the coagulant, for example, metal salts such as calcium chloride, calcium acetate or aluminum sulfate, sulfuric acid and the like can be used.

As the polymer (A), one type may be used alone, or two or more types may be used as a mixture.

Typical examples of the polycarbonate (B) used in the present invention include 4,4'-dioxydiarylalkanes such as 4,4'-dihydroxydiphenyl-2,2-propane (that is, bisphenol A) polycarbonate. Series polycarbonate. The molecular weight of the polycarbonate may be appropriately determined as desired, and is not particularly limited in the present invention. However, the weight average molecular weight of the polycarbonate (B) is preferably 20,000 to 100,000, more preferably 40,000 to 70,000.

The polycarbonate (B) may be produced by various conventionally known methods. For example, when producing 4,4'-dihydroxydiphenyl-2,2-propane-based polycarbonate, phosgene is used in the presence of an aqueous alkali solution and a solvent using 4,4'-dihydroxydiphenyl-2,2-propane as a raw material. And a production method in which 4,4′-dihydroxydiphenyl-2,2-propane is transesterified with a carbonic acid diester in the presence of a catalyst.

The thermoplastic resin composition of the present invention is a composition containing the above-mentioned polymer (A) and polycarbonate (B) as main components. The ratio of the two may be appropriately determined according to the desired physical properties and the like, and is not particularly limited in the present invention. In order to obtain an effective fluidity improving effect without lowering the inherent performance (impact strength, etc.) of the polycarbonate as a polycarbonate resin composition, the polymer (A)
And (A) 0.01 to 20 parts by mass, based on a total of 100 parts by mass of the polycarbonate (B) and
(B) 99.99 to 80 parts by mass, more preferably (A)
0.01 to 10 parts by mass, (B) 99.99 to 90 parts by mass.

Further, the thermoplastic resin composition of the present invention may optionally contain various conventionally known additives, stabilizers, reinforcing agents, inorganic fillers, impact modifiers and the like. Is also good.

Also, a masterbatch was prepared by mixing the polymer (A) and the polycarbonate (B) by increasing the ratio of the polymer (A) in advance, and then mixing the masterbatch and the polycarbonate (B) again. In addition, a desired composition can be obtained.

The thermoplastic resin composition of the present invention is, for example,
It is obtained by mixing the above components. As the mixing method, various conventionally known compounding methods and kneading methods can be used. For example, Henschel mixer, Banbury mixer, single screw extruder,
A method using a twin screw extruder, a two-roller, a kneader, a Brabender or the like can be used.

Using the thermoplastic resin composition of the present invention thus obtained as a raw material, molding can be performed by various conventionally known molding methods such as injection molding, hollow molding, extrusion molding, compression molding, and calendar molding. By performing the above, various molded articles having an excellent balance between fluidity and impact strength can be obtained.

The specific physical properties of the thermoplastic resin composition of the present invention may be appropriately adjusted as desired, and there is no particular limitation in the present invention. However, regarding the fluidity, the melt viscosity according to the measurement conditions of the examples described below is 2000 pois.
It is preferably equal to or less than e. Regarding the impact strength, the measurement conditions (ASTM D256) in Examples described later were used.
It is preferable that the Izod impact strength according to the above is 500 J / m or more. It can be said that a thermoplastic resin composition having such physical properties is very excellent in balance between fluidity and impact strength.

[0046]

Embodiments of the present invention will be described below.

Various physical properties in Examples and Comparative Examples were measured by the following methods.

(1) Solid Content The weight of the polymerized latex after drying at 170 ° C. for 30 minutes was measured to determine the solid content.

(2) Weight average molecular weight (Mw) Using a gel permeation chromatograph (GPC),
The eluent was measured in terms of chloroform and polymethyl methacrylate.

(3) Melt Viscosity For the resin composition, a nozzle D = 1 mm, L / D = 10, barrel temperature = 250 ° C., shear rate using a capillary rheometer (trade name: Capillograph, manufactured by Toyo Seiki Co., Ltd.) The measurement was performed under the condition of 6080 sec ^-1 .

(4) Izod Impact Strength (Izod) The thickness of the test piece was 3.2 m according to ASTM D256.
m, notched, temperature 23 ° C., humidity 50% RH. The test piece was measured at a cylinder temperature of 27 using an injection molding machine (IS-100 manufactured by Toshiba Machine Co., Ltd.).
Molding was performed under the conditions of 0 ° C. and a mold temperature of 80 ° C.

(5) Forming Appearance A test piece having a size of 100 × 100 × 3 mm was measured using an injection molding machine (IS-100 manufactured by Toshiba Machine Co., Ltd.) at a cylinder temperature of 270 ° C. and a mold temperature of 80 ° C. After molding, the obtained test piece was observed by visual observation, and a test piece having no laminar peeling was evaluated as good.

<Production Example 1. Production of Polymer (AI)> A separable flask equipped with a condenser and a stirrer was charged with 1.0 part by mass of sodium dodecylbenzenesulfonate and 188 parts by mass of distilled water, and placed in a water bath under a nitrogen atmosphere.
Heated to ° C. Next, 0.0004 parts by mass of ferrous sulfate and 0.001 disodium ethylenediaminetetraacetate were added.
2 parts by mass and 0.48 parts by mass of Rongalite are dissolved in 6 parts by mass of distilled water and added.
Parts by mass, 10 parts by mass of styrene, 0.2 parts by mass of allyl methacrylate, 0.2 parts by mass of n-octyl mercaptan,
0.1 part by weight of a mixture of cumene hydroperoxide was added to 4 parts.
It was added dropwise over 0 minutes. Thereafter, the mixture was stirred for 60 minutes to complete the first-stage polymerization. A small amount of the emulsion thus obtained was collected, and the weight average molecular weight (M
As a result of measurement of w), the weight average molecular weight was 30,000.

0.0004 parts by mass of ferrous sulfate, 0.0012 parts by mass of disodium ethylenediaminetetraacetate, and 0.48 parts by mass of Rongalite were dissolved in 6 parts by mass of distilled water and added to the emulsion. Thereafter, a mixture of 80 parts by mass of styrene, 0.8 parts by mass of n-octylmercaptan, and 0.4 parts by mass of cumene hydroperoxide was added dropwise over 140 minutes. Then stir for 60 minutes,
The second stage polymerization was completed. The solid content of the emulsion thus obtained was 32%.

This emulsion was poured into an aqueous solution of calcium chloride, and the resulting precipitate was dried to obtain a polymer (AI).
I got Its weight average molecular weight was 30,000.

<Production Example 2. Production of Polymer (A-II)> In Production Example 1, the compositions of the first and second stages are shown in Table 1.
(A-II) was obtained in the same manner as described above except that the above procedure was repeated. The solid content was 33%, and the molecular weight was 30,000 after the first-stage polymerization and 30,000 after the second-stage polymerization.

<Production Example 3. Production of Polymer (A-III)>
In Production Example 1, except that the compositions of the first and second stages were changed as shown in Table 1, the same operation was performed.
A polymer (A-III) was obtained. The solid content was 33%, and the molecular weight was 30,000 after the first polymerization.
After the second stage of polymerization, the weight average molecular weight was 30,000.

<Production Example 4. Production of Polymer (A-IV)> In Production Example 1, the compositions of the first and second stages are shown in Table 1.
The same operation was performed except that the polymer was changed as shown in (1) to obtain a polymer (A-IV). The solid content was 32%, and the molecular weight was 30,000 after the first-stage polymerization and 30,000 after the second-stage polymerization.

<Production Example 5> Production of Polymer (AV)> In Production Example 1, the compositions of the first and second stages are shown in Table 1.
The same operation was carried out except that the polymer was changed as shown in (1) to obtain a polymer (AV). The solid content was 33%, and the molecular weight was 30,000 after the first-stage polymerization and 30,000 after the second-stage polymerization.

<Production Example 6. Production of Polymer (A-VI)> A separable flask equipped with a condenser and a stirrer was charged with 1.0 part by mass of sodium dodecylbenzenesulfonate and 194 parts by mass of distilled water, and placed in a water bath at 60 ° C. under a nitrogen atmosphere.
Until heated. 0.0008 parts by mass of ferrous sulfate, 0.0024 parts by mass of disodium ethylenediaminetetraacetate,
0.96 parts by mass of Rongalite is dissolved in 6 parts by mass of distilled water and added. Thereafter, a mixture of 100 parts by mass of styrene, 1.0 part by mass of n-octylmercaptan and 0.5 part by mass of cumene hydroperoxide is added for 180 minutes. It dripped over. Thereafter, the mixture was stirred for 60 minutes to complete the polymerization. The solid content of the thus obtained emulsion was measured to be 32.
%was.

The emulsion was poured into an aqueous solution of calcium chloride, and the resulting precipitate was dried to obtain a polymer (A-VI). Its weight average molecular weight was 30,000.

<Production Example 7. Production of Polymer (A-VII)>
A polymer (A-VII) was obtained in the same manner as in Production Example 7, except that the composition was changed as shown in Table 2. The solid content was 32%, and the weight average molecular weight was 30,000.

<Production Example 8. Production of Polymer (A-VIII)>
A polymer (A-VIII) was obtained in the same manner as in Production Example 7, except that the composition was changed as shown in Table 2. The solid content was 32%, and the weight average molecular weight was 30,000.
This polymer (A-VIII) was tacky and easily blocked.

<Production Example 9. Production of Polymer (A-IX)> In Production Example 1, the compositions of the first and second stages are shown in Table 2.
(A-IX) was obtained in the same manner as above except that the above procedure was repeated. The solid content was 32%, and the molecular weight was 30,000 after the first-stage polymerization and 30,000 after the second-stage polymerization.

<Production Example 10. Production of Polymer (AX)>
In Production Example 1, except that the compositions of the first and second stages were changed as shown in Table 3, the same operation was performed.
A polymer (AX) was obtained. The solids content was 33%. The polymer after the first and second polymerization steps was a gel insoluble in chloroform, and the molecular weight could not be measured.

<Production Example 11> Production of Polymer (A-XI)>
In Production Example 1, except that the compositions of the first and second stages were changed as shown in Table 3, the same operation was performed.
A polymer (A-XI) was obtained. The solids content was 32%. The polymer after the first and second polymerization steps was a gel insoluble in chloroform, and the molecular weight could not be measured.

<Production Example 12> Production of Polymer (A-XII)> In Production Example 1, except that the compositions of the first and second stages were changed as shown in Table 3, the same operation was carried out to obtain the polymer (A-XII). XII). The solid content was 32%, and the molecular weight was 3 weight average molecular weight after the first stage polymerization.
After the second stage polymerization, the weight average molecular weight was 30,000.

<Production Example 13> Production of Polymer (A-XIII)> In Production Example 1, except that the compositions of the first stage and the second stage were changed as shown in Table 3, the same operation was performed to obtain the polymer (A-XIII). XIII). The solid content was 33%, and the molecular weight was 3% after the first polymerization.
After the second stage polymerization, the weight average molecular weight was 30,000.

<Examples 1 to 5 and Comparative Examples 1 to 9> Polycarbonate (Mitsubishi Engineering Plastics, Inc.)
(S2000), the weight average molecular weight of which is about 50,000) and the polymers (AI) to (A-XIII) obtained in Production Examples 1 to 13.
Are mixed at the ratios shown in Tables 1 to 3 below, and a 30 mmφ twin-screw extruder (“ZS manufactured by WERNER & PFLEIDERER”)
Using K30 ”), a thermoplastic resin composition was extruded under the conditions of a barrel temperature of 270 ° C. and a screw rotation speed of 200 rpm. Their melt viscosity, impact strength and molded appearance were evaluated. The results are shown in Tables 1 to 3.

Abbreviations in Table BA: butyl acrylate EHMA: 2-ethylhexyl methacrylate St: styrene MMA: methyl methacrylate AMA: allyl methacrylate EDMA: ethylene glycol dimethacrylate OcSH: n-octyl mercaptan PC: polycarbonate

[Table 1]

[Table 2]

[Table 3] <Evaluation> As is clear from the results shown in Table 1, Examples 1 to
In No. 5, the melt viscosity was 2000 poise or less, the Izod impact strength was 500 J / m or more, and the balance between fluidity and impact strength was excellent. Further, in order to better prevent poor molding appearance of the resin composition, the resin composition contains an aromatic vinyl monomer (a-2) and a monomer (a-3) having two or more unsaturated groups. It was effective to use the polymer (A).

On the other hand, in Comparative Example 1, since only the polycarbonate (B) was used without using the polymer (A), the fluidity was poor. In Comparative Examples 2 to 4, an alkyl (meth) acrylate and a polymer (A-VI), (A-VII) or (A-VIII) obtained by one-stage polymerization of an aromatic vinyl monomer were used. Therefore, the impact strength of the resin composition was inferior, and in Comparative Example 4, the molding appearance of the resin composition and the handleability of the polymer (A-VIII) itself were inferior. In Comparative Example 5, since the polymer (A-IX) containing no alkyl (meth) acrylate (a-1) was used, the impact strength of the resin composition was poor. In Comparative Examples 6 and 7, since the crosslinked gel polymer (AX) or (A-XI) was used, the fluidity of the resin composition was poor. In Comparative Example 8, a polymer (A-XII) containing no monomer (a-3) having two or more unsaturated groups
, The molding appearance of the resin composition was inferior. In Comparative Example 9, the alkyl (meth) acrylate (a
-1), the alkyl group has a small number of carbon atoms (1
) A polymer containing methyl methacrylate (A-XII
Since I) was used, the impact strength of the resin composition was poor.

[0072]

As described above, according to the present invention,
Polycarbonate-based thermoplastic resin composition that can dramatically improve its moldability (fluidity, etc.) without impairing the excellent mechanical properties (impact strength, etc.) inherent to polycarbonate, and have a good balance of both properties Can be obtained.

Since the thermoplastic resin composition of the present invention has an excellent balance between mechanical properties and moldability, it is possible to reduce the size and thickness of molded articles especially in various fields such as home appliances and housings of OA equipment. It makes it possible, and its industrial value is enormous.

Claims (3)

[Claims] 1. An alkyl (meth) acrylate having an alkyl group having 2 to 20 carbon atoms (a-1) in an amount of 15 to 100% by mass, an aromatic vinyl monomer (a-2) in an amount of 85 to 0% by mass, and In the presence of a polymer obtained by polymerizing a monomer (a-3) having two or more saturated groups, an aromatic vinyl monomer (a-
A thermoplastic resin composition containing a polymer (A) substantially free of gel obtained by polymerizing 4) and a polycarbonate (B). 2. An alkyl (meth) acrylate (a-
1) is ethyl (meth) acrylate, butyl (meth)
The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition is at least one monomer selected from the group consisting of acrylate and 2-ethylhexyl (meth) acrylate. 3. An alkyl (meth) acrylate having an alkyl group having 2 to 20 carbon atoms (a-1) in an amount of 15 to 100% by mass, an aromatic vinyl monomer (a-2) in an amount of 85 to 0% by mass, The thermoplastic resin composition according to claim 1 or 2, wherein the polymer obtained by polymerizing the monomer (a-3) having two or more saturated groups has a weight average molecular weight of 3000 to 300,000.