JP3386532B2 - Thermoplastic resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition which has excellent impact resistance and heat distortion resistance and provides a molded article having an excellent surface appearance and also excellent moldability. Is.

[0002]

2. Description of the Related Art ABS resin is used for impact resistance, heat distortion resistance, and
Since it has a good balance of molding processability, it is used for a wide range of applications such as automobiles, electronic and electrical parts. In recent years, with the miniaturization and weight reduction of these applications, the
It is required to improve the balance of moldability. Various methods have been proposed in the past for improving the balance between physical properties and moldability, but none have been proposed yet. For example, the method of copolymerizing α-methylstyrene for the purpose of improving the heat distortion resistance lowers the molding processability, and the method of copolymerizing maleimide lowers the impact resistance, both of which are not sufficient. Further, for the purpose of compensating for these drawbacks, a method of adding an ethylene-acrylate copolymer has been investigated, but it is not satisfactory.

[0003]

SUMMARY OF THE INVENTION The present invention provides a thermoplastic resin composition having a good balance of physical properties and moldability.

[0004]

Means for Solving the Problems As a result of intensive studies to overcome such problems, the present inventors have found that a graft copolymer using a rubber-like polymer having a specific particle size distribution and a specific amount of maleimide are used. It was found that a resin composition having a good balance of impact resistance, heat distortion resistance, and moldability can be obtained by mixing a monomer mixture containing a copolymer with a copolymer, which has led to the present invention. . That is, the present invention has a weight average particle diameter of 0.2 to 0.6 μm and a weight average particle diameter of 0.15 to 0.8.
a graft copolymer (A) obtained by grafting aromatic vinyl and vinyl cyanide in a specific ratio to a rubber-like polymer having a particle size in the range of μm of 60% by weight or more and a glass transition temperature of −30 ° C. or less. Containing a specific amount of maleimide,
It is intended to provide a thermoplastic resin composition obtained by mixing a maleimide and vinyl cyanide with a copolymer (B) composed of aromatic vinyl. The weight average particle diameter in the present invention is a value measured by a transmission electron microscope using an ultrathin film slice (500 to 1000Å).

The rubber-like polymer used in the graft copolymer (A) has a weight average particle size of 0. 0 as measured by a transmission electron microscope using an ultrathin film section (500 to 1000Å).
2 to 0.6 μm, and the proportion of particles in the range of 0.15 to 0.8 μm is 60% by weight or more. The polymerization average particle diameter is preferably 0.25 to 0.5 μm, and 0.2 to 0.
The proportion of particles in the range of 7 μm is 70% by weight or more, and the proportion of particles in the range of 0.3 to 0.5 μm is 30% by weight.
That is all. The glass transition temperature of the rubbery polymer is -30 ° C.
It is below, preferably below -50 ° C. If the weight average particle size and particle size distribution of the rubber-like polymer are out of the above ranges, impact resistance and rigidity are lowered. When the glass transition temperature is higher than -30 ° C, the impact resistance is lowered. The gel content of the rubber-like polymer is not particularly limited, but is 60 to 9
The range of 0% by weight is preferable.

Specific examples of the rubber-like polymer include polybutadiene and styrene-butadiene copolymer (SB
R), acrylonitrile-butadiene copolymer (NB
R), diene rubber such as butyl acrylate-butadiene copolymer, ethylene-propylene copolymer (EP
R), ethylene-propylene-diene copolymer (EPD
Olefin rubbers such as M), polybutyl acrylate,
An acrylic rubber such as poly-2-ethylhexyl is shown,
These are used alone or in combination of two or more.

The graft branch composition of the graft copolymer (A) is as follows: aromatic vinyl 40 to 60 mol%, vinyl cyanide 6
It is in the range of 0 to 40 mol%, preferably 49 to 60 mol% of aromatic vinyl and 51 to 40 mol% of vinyl cyanide. If the composition of the graft branch is out of the above range, impact resistance is lowered, thermal stability is lowered, and coloring occurs. Specific examples of aromatic vinyl include styrene, α-methylstyrene, methylstyrene, chlorostyrene, and the like, and specific examples of vinyl cyanide include acrylonitrile, methacrylonitrile, and the like, and these may be used alone or in combination of two or more. Used in combination.

The graft ratio [(weight of graft branch / weight of rubber-like polymer) × 100] is 20 to 100%, preferably 30 to 70%. If the graft ratio is out of the above range, the impact resistance is lowered, the rigidity is lowered, and the moldability is lowered. The intrinsic viscosity (N, N dimethylformamide solution, 30 ° C.) of the ungrafted polymer is not particularly limited, but a range of 0.3 to 1.0 dl / g is preferable. The method for producing the graft copolymer (A) can be carried out by ordinary emulsion polymerization, emulsion-suspension polymerization, suspension polymerization, emulsion-bulk polymerization, solution polymerization or the like, and is not particularly limited.

The copolymer (B) used in the present invention comprises 5 to 30 mol% of maleimide, 40 to 60 mol% of total maleimide and vinyl cyanide, and 6 to aromatic vinyl.
It is in the range of 0 to 40 mol%. More preferably, maleimide 5 to 30 mol% and vinyl cyanide 45 to 30 mol%
And the total amount of maleimide and vinyl cyanide is 40-
It is in the range of 55 mol% and aromatic vinyl 60 to 45 mol%. Outside the above range, the impact resistance is reduced, the heat distortion resistance and the moldability are reduced, the thermal stability is deteriorated,
Coloring occurs. Specific examples of the maleimide used include phenylmaleimide, N-maleimide, cyclohexylmaleimide and the like, and these may be used alone or in combination of two or more. Specific examples of the aromatic vinyl and vinyl cyanide include those exemplified for the graft copolymer (A).

Intrinsic viscosity (N, N dimethylformamide solution, 30) of the methyl ethyl ketone soluble component of the copolymer (B)
C) is in the range of 0.4 to 1.5 dl / g, preferably 0.5 to 0.9 dl / g. Outside this range, the impact resistance is lowered, the chemical resistance is lowered, and the moldability is lowered. The method for producing the copolymer (B) is not particularly limited, and it can be produced by the method exemplified for the graft copolymer (A).

The impact resistance, heat distortion resistance, molding processability, etc. of the thermoplastic resin of the present invention are not limited to the respective compositions of the graft copolymer (A) and the copolymer (B), and their respective mixing ratios. Is also affected by. Therefore, the mixing ratio may be determined according to the desired physical property values, but in order to preferably achieve the present invention, the rubber-like polymer may be contained in an amount of 5 to 5 in the composition after mixing.
Mix to give 35% by weight. The mixing may be performed by a known method. For example, the latex of the graft copolymer (A) obtained by emulsion polymerization and the latex of the copolymer (B) may be mixed, salt-folded, and the solidified product may be dried before use. The powder or pellets of the graft copolymer (A) and the copolymer (B) may be kneaded with a roll, a screw, a Banbury mixer, a kneader or the like before being used. If necessary, stabilizers, lubricants, plasticizers, light stabilizers, UV absorbers, pigments, fillers and the like can be added during mixing. Further, it is also possible to mix a polycarbonate resin, a polyvinyl chloride resin, a polyethylene terephthalate resin, a polybutylene terephthalate resin and the like.

[0012]

EXAMPLES The present invention will now be specifically described with reference to examples, but the present invention is not limited to these examples. Examples 1 to 8 and Comparative Examples 1 to 8 (a) Production of graft copolymer (A) Water 280 (parts by weight) Sodium formaldehyde sulfoxylate 0.2 (〃) Ferrous sulfate 0.0025 (〃) Ethylenediaminetetraacetic acid disodium 0.01 (〃) The above substance and the rubber-like polymer latex shown in Table 1 were charged into a reactor equipped with a stirrer. After deoxidation, 60 in nitrogen stream
After heating and stirring at 0 ° C., the monomer mixture shown in Table 1 was mixed with 10
Parts by weight / 1 hour continuously, and at the same time continuously add potassium rosin acid in a proportion of 0.2 parts by weight / 10 parts by weight of the monomer mixture, and after the dropping is completed, at 60 ° C. for 1 hour. After continuing stirring, the polymerization was completed. Using the obtained latex, the polymerization conversion rate, graft ratio, graft branch composition, and ungrafted polymer composition were measured by gas chromatography, centrifugation, and elemental analysis. The results are shown in Table 1.

[0013]

[Table 1]

The abbreviations in Table 1 represent the following. PBD: polybutadiene SBR: styrene-butadiene copolymer AN: acrylonitrile St: styrene CHP: cumene hydroperoxide

(B) Production of copolymer (B) The following substances were charged in a reactor equipped with a stirrer. Water 250 (parts by weight) Sodium alkylbenzene sulfonate 2 (〃) Potassium persulfate 0.2 (〃) After deoxidation, heat and agitate at 70 ° C in a nitrogen stream, and then Table 2
Was continuously added dropwise over 7 hours,
After completion of the dropping, stirring was continued for 1 hour to complete the polymerization. Using the obtained latex, gas chromatography and elemental analysis were performed to measure the solution viscosity. The results are shown in Table 2.

[0016]

[Table 2]

(C) Production of thermoplastic resin composition The graft copolymer (A) and the copolymer (B) produced as described in the above (a) and (b) are mixed in a latex state at a ratio shown in Table 3. Then, after adding a phenolic antioxidant and coagulating with calcium chloride, it was washed with water, filtered and dried to obtain a powder. The obtained powder was pelletized by a vent type extruder and used for measurement of physical properties. The measurement results are shown in Table 3.

The physical properties were measured by the following methods. Izod impact value (kg ・ cm / cm): ASTM D-25
6, 23 ° C Drop weight strength (kg · m): Using a test piece having a length of 150 mm, a width of 100 mm, and a thickness of 3 mm, the half fracture height × weight of the weight, 23 ° C heat distortion temperature (° C): ASTM D-56, 18.6kg /
cm ² Tensile strength (kg / cm ² ): ASTM D-636, 23 ° C Spiral flow value: Measured at a nozzle temperature of 250 ° C, an injection pressure of 1000 kg / cm ² , and a mold temperature of 40 ° C using a 3 ounce injection molding machine.

[0019]

[Table 3]

[0020]

As shown in Table 3, the thermoplastic resin composition of the present invention has excellent impact resistance and thermal deformation resistance, as well as good moldability.

Claims (3)

(57) [Claims] 1. A rubber having a weight average particle diameter of 0.2 to 0.6 μm and containing 60% by weight or more of particles in the range of 0.15 to 0.8 μm and having a glass transition temperature of −30 ° C. or lower. A graft polymer (A) having a graft ratio of 20 to 100%, in which aromatic vinyl and vinyl cyanide are grafted at a molar ratio of 40 to 60:60 to 40, and maleimide is 5 To 30 mol%, the total amount of maleimide and vinyl cyanide is 40 to 60 mol%, aromatic vinyl is 60 to 40 mol%, and the intrinsic viscosity is 0.4.
A thermoplastic resin composition obtained by mixing the copolymer (B) having an amount of ˜1.5 dl / g so that the rubber-like polymer becomes 5 to 35% by weight. 2. The rubber-like polymer has a weight average particle diameter of 0.
25 to 0.5 μm, containing 70% by weight or more of particles in the range of 0.2 to 0.7 μm, and 0.3 to 0.5 μm
The thermoplastic resin composition according to claim 1, which contains 30% by weight or more of particles in the range. 3. The composition of the copolymer (B) is maleimide 5 to 5.
30 mol%, vinyl cyanide 45 to 30 mol%, the total amount of maleimide and vinyl cyanide is 40 to 55 mol%, and aromatic vinyl 60 to 45 mol%, and the intrinsic viscosity is 0.5 to 0. It is 9 dl / g, The thermoplastic resin composition of Claim 1 or 2.