JP2999944B2 - 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 is excellent in heat resistance, weather resistance, molding processability and the surface appearance of a molded product.

[0002]

2. Description of the Related Art Resins used in the field of vehicle exterior parts, such as lamp housings for automobiles, are thermoplastic resins which are excellent not only in shock resistance but also in heat resistance and weather resistance. Is required. AB is a typical impact-resistant thermoplastic resin
There is S resin. In order to increase the heat resistance of the ABS resin, recently, a maleimide-based copolymer obtained by copolymerizing a maleimide compound, an unsaturated cyanide compound and an aromatic vinyl compound has been used as a matrix resin.

[0003] On the other hand, the ABS resin uses polybutadiene, which is a conjugated diene rubber, as a rubber component, and has a drawback that it is inferior in weather resistance because it is easily decomposed by ultraviolet rays. In order to improve this weather resistance,
An AAS resin having an acrylic ester rubber as a rubber component is used, but the AAS resin is inferior in impact resistance to the ABS resin. For this reason, in recent years, the impact resistance of the AAS resin has been improved. For example, as described in Japanese Patent Publication No. 3-66329, a conjugated diene-based rubber having a inferior amount and an acrylate-based rubber having an superior amount are combined. Specialized AAS resin has been proposed. Therefore, as a method for obtaining a thermoplastic resin having excellent heat resistance and weather resistance, it is conceivable to mix a maleimide-based copolymer and a special AAS resin.

[0004] However, a thermoplastic resin composition containing a maleimide copolymer and a special AAS resin has a problem that the surface appearance of a molded article is deteriorated although it has both heat resistance and weather resistance. ing. In other words, there is a problem that a so-called poor appearance occurs in which the surface of the molded product becomes cloudy or glossy spots in which the gloss disappears partially are observed.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above-mentioned situation, and as a result, the rubber component used in the graft copolymer has the above-mentioned specific gel content. The present inventors have found that the problem can be solved and arrived at the present invention. That is, the present invention relates to (A) a rubber component composed of one kind of a composite rubber of a conjugated diene-based rubbery polymer and an acrylate-based rubbery polymer, or a conjugated diene-based rubbery polymer and an acrylate-based rubber component. 2 of composite rubber with rubber-like polymer and acrylate-based rubber-like polymer
A rubber component 40 to 70% by weight of a seed, a graft component 60 comprising a copolymer of 15 to 45% by weight of an unsaturated cyanide unit and 85 to 55% by weight of an aromatic vinyl compound unit
To 30% by weight of a graft copolymer [I]
15 to 50 parts by weight, and (B) maleimide compound unit 1
0 to 50% by weight, 35 to 80% by weight of an aromatic vinyl compound unit and 10 to 35% by weight of an unsaturated cyanide unit
(However, the total amount of each component is 100% by weight) is a maleimide-based copolymer, and in the maleimide-based copolymer, the molecular weight of which maleimide-based compound is an essential component is 200 or more and 1000 or more. 40 to 85 parts by weight of a maleimide-based copolymer [II] containing 2 to 10% by weight of the following oligomer component, (C) 15 to 45% by weight of an unsaturated cyanogen compound unit and 85 to 85% of an aromatic vinyl compound unit
0 to 40 parts by weight of a copolymer [III] composed of 55% by weight (the total amount of components [I], [II] and [III] is 100 parts by weight) )
Wherein the gel content (toluene-insoluble content) of the rubber component in the graft copolymer [I] is 85% by weight or more.

Hereinafter, the present invention will be described in detail. The composite rubber used in the graft copolymer [I] of the present invention is obtained by mixing an acrylate ester with a cross-linking agent and a graft crosslinking agent in the presence of 5 to 40% by weight (as solid content) of a conjugated diene rubber-like polymer latex. Mixture consisting of an agent and 60 to 95
% By weight (total amount: 100% by weight) by seed polymerization.

The conjugated diene rubbery polymer used in the present invention is a conjugated diene homopolymer or a conjugated diene of 70% by weight or more and another monomer copolymerizable therewith.
0% by weight or less. Examples of the conjugated diene include 1,3-butadiene, isoprene and chloroprene, and other copolymerizable monomers include:
Examples thereof include unsaturated cyanide compounds such as acrylonitrile and aromatic vinyl compounds such as styrene. Preferred examples of the conjugated diene rubbery polymer include polybutadiene rubber, acrylonitrile-butadiene copolymer rubber, styrene-butadiene copolymer rubber, and the like, with polybutadiene rubber being most preferred. Those obtained by a known emulsion polymerization method are used.

The conjugated diene-based rubber-like polymer latex has a large average particle size of 0.2 to 1.0 μm in terms of the impact resistance of the resin composition. Such a large-particle rubber may be obtained over a long period of time by several stages of seed polymerization, but can be obtained efficiently by an enlargement operation, that is, a base rubber of 0.03 to 0.15 μm. It is preferable to use a rubber latex enlarged to a desired size by adding an acid group-containing copolymer latex to the latex.

[0009] The acid group-containing copolymer latex comprises one or more unsaturated acids selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, crotonic acid, cinnamic acid, sorbic acid and p-styrenesulfonic acid. ~ 40% by weight,
One or more acrylates having 1 to 12 carbon atoms in the alkyl group can be obtained by emulsion polymerization with 97 to 60% by weight. Among these, a copolymer of methacrylic acid and butyl acrylate is a preferred example.

[0010] The acid group-containing copolymer latex added for the enlargement operation has a solid content of 0.5 to 0.5 parts by weight based on 100 parts by weight (as solid content) of a conjugated diene rubbery polymer latex serving as a base rubber. 8 parts by weight. 0.2-1.0
In order to enlarge the particles to large particles of μm, it is necessary to adjust the pH of the base rubber latex to 9 or more and use an acid group-containing copolymer latex containing a large amount of unsaturated acid. In the enlargement operation, it is rare that all the base rubber becomes the enlargement rubber, and the base rubber which normally could not participate in the enlargement remains. Therefore, the enlarged rubber has a particle size distribution of two dispersions. However, even if a small amount of non-enlarged particles remain, a resin composition of the present invention can be obtained at a level which has almost no problem in physical properties.

The composite rubber latex has a thickness of 0.2 to 1.0 μm.
m in the presence of a conjugated diene rubbery polymer latex
It is obtained by subjecting a monomer mixture composed of an acrylate ester, a crosslinking agent and a graft crosslinking agent to seed polymerization.

The acrylate used herein refers to an alkyl acrylate having an alkyl group having 1 to 12 carbon atoms or an aromatic acrylate having a benzene ring such as a phenyl group or a benzyl group. For example, n-butyl acrylate, 2-acrylic acid
Ethylhexyl, ethyl acrylate and the like;
Species or two or more species can be used. If the amount used is 30% by weight or less, an acrylate compound having a functional group such as glycidyl acrylate, 2-hydroxyethyl acrylate, tetrahydrofurfuryl acrylate, or dimethylaminoethyl acrylate may be used as described above. They can be used together.

Examples of the crosslinking agent include divinylbenzene, ethylene glycol diacrylate, ethylene glycol dimethacrylate, butylene glycol diacrylate, butylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, triallyl cyanurate, triallyl. Examples include isocyanurate and trimethylolpropane triacrylate, and examples of the graft crosslinking agent include allyl acrylate, allyl methacrylate, and allyl itaconate. The type and amount of the crosslinking agent and the graft crossing agent used are determined so that the gel content of the rubber component and the ratio of the graft component to the rubber component are in the optimum ranges.

When seed-polymerizing a monomer mixture such as an acrylate ester in the presence of a conjugated diene-based rubber-like polymer latex, when all of the monomer mixture is seed-polymerized to a conjugated diene-based rubber-like polymer, Can obtain only a composite rubber of a conjugated diene-based rubbery polymer and an acrylate-based rubbery polymer, but in some cases, all of the monomer mixture is not seed-polymerized into the conjugated diene-based rubbery polymer but partially. A single acrylate-based rubbery polymer latex may be formed. In the latter case, two types of rubber components, that is, a composite rubber of a conjugated diene rubber-based polymer and an acrylate rubber-based polymer, and an acrylate rubber-based polymer are present. become. Therefore, the present invention also includes a thermoplastic resin composition containing the graft copolymer [I] obtained by using the above two types of rubber components.

The ratio of the conjugated diene-based rubbery polymer and the acrylate ester-based rubbery polymer (total amount of the seeded portion and the portion existing alone) in the rubber component is determined by the ratio of the conjugated diene-based rubbery polymer 5 -40% by weight and 95-60% by weight of an acrylate rubbery polymer. If the proportion of the conjugated diene-based rubbery polymer is less than 5% by weight, the impact resistance of the resin composition decreases, while if it exceeds 40% by weight, the weather resistance of the resin composition decreases, which is not preferable. .

The seed polymerization is carried out by emulsion polymerization, in which the monomer mixture is added dropwise to the polymerization system while polymerizing as needed, or after the monomer mixture is impregnated in advance with the conjugated diene rubber-like polymer. Examples of the method include a method of adding an initiator and polymerizing, and a method of repeating the operation of impregnating the monomer mixture and then polymerizing several times while changing the composition of the monomer mixture in each stage. In the case of seed polymerization, an emulsifier can be newly added for the purpose of improving the stability of the polymerization system.

The gel content (toluene-insoluble matter) of the rubber component obtained by seed polymerization must be 85% by weight or more in order not to impair the surface appearance of the resin composition.
More preferably, it is required to be 90% by weight or more. Such a gel content can be optimized by optimizing the type and amount of a cross-linking agent used in combination with an acrylate ester during seed polymerization, or by setting the polymerization temperature, initiator amount, or polymerization time (dropping the monomer mixture. In this case, the dropping time is adjusted.

The obtained rubber component latex is subsequently subjected to graft polymerization. The graft polymerization is carried out by polymerizing 60 to 30% by weight of a monomer mixture composed of an unsaturated cyanide compound and an aromatic vinyl compound in the presence of 40 to 70% by weight (as solid content) of a rubber component latex. When the rubber component is less than 40% by weight, the amount of the graft copolymer necessary for expressing the impact resistance of the resin composition increases, and the amount of the maleimide-based copolymer decreases accordingly, lowering the heat resistance. Therefore, it is not preferable. Also, 7
If it exceeds 0% by weight, coarse particles are formed in the coagulation step performed after the graft polymerization and cannot be recovered, which is not preferable.

As the unsaturated cyanide compound used for the graft polymerization, acrylonitrile, methacrylonitrile,
Ethacrylonitrile, maleonitrile, fumaronitrile, and the like are exemplified, and acrylonitrile is a preferred example. Examples of the aromatic vinyl compound include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pt-butylstyrene, and halogenated styrene. α-methylstyrene is a preferred example. The ratio between the unsaturated cyanide compound and the aromatic vinyl compound used is the impact resistance and moldability of the resin composition,
From the viewpoint of heat resistance coloring, the content is in the range of 15 to 45% by weight of the unsaturated cyanide compound and 85 to 55% by weight of the aromatic vinyl compound.

As the graft polymerization method, a known emulsion polymerization method can be employed. A method of polymerizing after charging the monomer mixture in a lump, a method of charging a part of the monomer mixture first and dropping the remaining portion, a method of optionally polymerizing while dropping the entire amount of the monomer mixture, It can be carried out in one stage or in two or more stages, and in this case, it can be carried out by changing the type and composition ratio of the monomer mixture in each stage. In the graft polymerization, not all of the monomer mixture is graft-bonded to the rubber component as a graft component, and often becomes a partially free copolymer. Such a copolymer will be present as a copolymer [III] in the resin composition. The obtained graft copolymer [I] latex is coagulated by a known method, and is subjected to dehydration, washing, drying and other steps.
It is obtained as a graft copolymer [I].

The maleimide-based copolymer [II] comprises 10 to 50% by weight of the maleimide-based compound and the aromatic vinyl compound 35.
It can be obtained by copolymerizing a monomer mixture consisting of ８０80% by weight and an unsaturated cyanide compound of 10 to 35% by weight (the total amount of each component is 100% by weight).

Here, the maleimide-based compound includes maleimide, N-methylmaleimide, N-ethylmaleimide,
-Propylmaleimide, N-isopropylmaleimide,
N-cyclohexylmaleimide, N-phenylmaleimide, N-toluylmaleimide, N-xylylmaleimide, N-naphthylmaleimide, Nt-butylmaleimide, N-orthochlorophenylmaleimide, N-orthomethoxyphenylmaleimide, N-ortho Bromophenylmaleimide and the like are exemplified. Of these, N-cyclohexylmaleimide, N-orthochlorophenylmaleimide, N-orthobromomaleimide, and N-phenylmaleimide are preferred examples, and N-phenylmaleimide is particularly preferred. These maleimide compounds can be used alone or in combination of two or more. The content of the maleimide-based compound unit in the maleimide-based copolymer is preferably from 10 to 50% by weight. Maleimide compound unit content is 10% by weight
When the amount is less than 50%, the heat resistance of the resin composition is lowered. On the other hand, when the amount is more than 50% by weight, the molding processability is deteriorated and the impact resistance of the resin composition is deteriorated.

As the aromatic vinyl compound, styrene,
α-methylstyrene, o-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pt-butylstyrene, halogenated styrene and the like are exemplified, and styrene or α-methylstyrene is exemplified as a preferred example. . The amount of the aromatic vinyl compound used is preferably from 35 to 80% by weight. When the amount is less than 35% by weight, the moldability decreases. When the amount exceeds 80% by weight, the heat resistance or impact resistance of the resin composition is impaired due to the relatively small amount of the maleimide compound or unsaturated cyanide compound used. It is not preferable.

As the unsaturated cyanide compound, acrylonitrile, methacrylonitrile, ethacrylonitrile, maleonitrile, fumaronitrile and the like are exemplified, and acrylonitrile is a preferred example. The use amount of the unsaturated cyanide compound is preferably from 10 to 35% by weight. 10
If it is less than 10% by weight, the impact resistance of the resin composition will be low,
If it exceeds 35% by weight, thermal coloring occurs, which is not preferable.

The maleimide-based copolymer [II] contains 2 to 10% by weight, preferably 3 to 9% by weight of an oligomer component having a maleimide-based compound as an essential component and having a molecular weight of 200 to 1,000. The content of the oligomer component can be determined from the ratio of the area of the peak in the corresponding range to the area of all the peaks in the elution curve of gel permeation chromatography. The monomer component constituting the oligomer component can be determined by elemental analysis after drying the eluate of the oligomer component separated and collected by GPC to remove the solvent. The constituent unit of the oligomer component must contain a maleimide-based compound unit, and an oligomer component that does not contain a maleimide-based compound unit is not preferred because it lowers the mechanical strength of the resin composition. The oligomer component needs to have a molecular weight of 200 or more and 1000 or less, and an oligomer component of less than 200 is not preferable because it causes a silver streak during molding.
On the other hand, an oligomer component having a molecular weight of more than 1000 is not preferable because it does not contribute to the improvement of moldability. On the other hand, when the content of the oligomer component is less than 2% by weight, the effect of improving the moldability of the resin composition is not observed.
When the content of the oligomer component is more than 10% by weight, the mechanical strength of the resin composition is lowered and thermal coloring is caused.

Further, in the maleimide-based copolymer [II], the content of the residual maleimide-based compound in the copolymer is preferably 0.1% by weight or less, more preferably 0.05% by weight or less. When the content of the residual maleimide compound exceeds 0.1% by weight, the resin composition is colored when the resin composition is obtained, or thermal coloring or bleed-out during molding is preferably performed. Absent. The maleimide-based copolymer [II] is produced by a known polymerization method, but is most preferably produced by a solution polymerization method.

The copolymer [III] is an unsaturated cyanide compound 1
5-45% by weight and aromatic vinyl compound 85-55% by weight
By copolymerizing a monomer mixture consisting of The unsaturated cyanide compound and the aromatic vinyl compound are preferably used in the same kind and amount as those described in the section of the graft copolymer [I]. Copolymer [III]
May be by-produced during the graft polymerization as described in the description of the graft copolymer [I], but may be separately produced for the purpose. Copolymer [I
II] is to use a low molecular weight copolymer to further enhance the moldability of the resin composition, and to increase the melt strength (melt tension) during heating and melting, to increase the high molecular weight copolymer. Use of coalescence and the like. The copolymer [III] is used as needed, and the amount used is 0 to
It is in the range of 40% by weight. The production of the copolymer [III] is carried out by a known polymerization method, but preferably produced by a solution polymerization method or a suspension polymerization method.

The thermoplastic resin composition of the present invention comprises 15 to 50 parts by weight of the graft copolymer [I], 40 to 85 parts by weight of the maleimide copolymer [II] and, if necessary, the copolymer.
[III] 0 to 40 parts by weight (however, the total of components [I], [II] and [III] is 100 parts by weight).
If the amount of the graft copolymer [I] is less than 15 parts by weight, the impact resistance of the resin composition will be low. On the other hand, if it is more than 50 parts by weight, the heat resistance of the resin composition will be undesirably reduced. When the amount of the maleimide-based copolymer [II] is less than 40 parts by weight, the heat resistance of the resin composition decreases,
On the other hand, when the amount exceeds 85 parts by weight, the impact resistance of the resin composition is lowered, which is not preferable. Further, if the blending amount of the copolymer [III] exceeds 40 parts by weight, the blending amount of the graft copolymer [I] or the maleimide-based copolymer [II] becomes relatively small, and the impact resistance of the resin composition is reduced. It is not preferable because the heat resistance or heat resistance is impaired.

When compounding the graft copolymer [I], the maleimide copolymer [II] and the copolymer [III],
If necessary, various stabilizers such as antioxidants and light stabilizers, lubricants, plasticizers, release agents, dyes, pigments, antistatic agents,
Inorganic fillers and the like can be added. These mixtures are melt-kneaded using a screw extruder, a mixing roll, or the like, and then pelletized by a pelletizer.

[0030]

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples. In the examples and comparative examples, “parts” represents “parts by weight”. Various physical property evaluations in Examples and Comparative Examples were performed using the following methods.

(1) Gel Content of Rubber Component 0.25 g of the dried rubbery polymer sample is immersed in 100 cc of toluene at 95 ° C. for 6 hours, and then filtered through a 100 mesh wire net. Next, the insoluble matter remaining on the wire net was vacuum-dried, the weight of the insoluble matter was weighed, and the weight was divided by the sample weight to determine the gel content (%) of the rubber component.

(2) Average particle size of conjugated diene rubber latex The diluted solution of the polymer latex was fixed by exposing it to the vapor of ruthenium tetroxide, and a photograph was taken with a transmission electron microscope. From this, the average particle size was determined.

(3) Izod impact strength (Iz) ASTM D-256 (1/4 inch, unit: kg · c)
m / cm).

(4) Melt index (MI) JIS K7210 (220 ° C., load 10 kg, g / 10
Min).

(5) Vicat softening temperature (VST) Measured according to ISO R-306 (unit: ° C.).

(6) Gloss The gloss was measured according to ASTM-D523 (incident angle: 60 °).
The evaluation specimen was 100 mm x 100 mm molded at 270 ° C.
A 3 mm (thickness) flat plate was used.

(7) Weather Resistance 6 using Sunshine Super Long Life Weather Meter, WEL-SUN-DCH type, manufactured by Suga Test Instruments Co., Ltd.
50 under the condition of 3 ° C rain (60 minutes cycle rain 12 minutes)
Exposure was for 0 hours. The surface gloss at this time was measured by the above method (6), and the gloss retention (%) with respect to the surface gloss before exposure.
Was evaluated.

Synthesis of conjugated diene rubbery polymer latex 1,3-butadiene 100 parts Diisopropylbenzene hydroperoxide 0.2 parts t-dodecylmercaptan 0.5 parts Potassium oleate 1 part Disproportionated potassium rosinate 1 part Dextrose 0.3 part Anhydrous sodium sulfate 0.18 part Sodium hydroxide 0.02 part Distilled water 195 parts All the above substances were charged into a 50 liter autoclave and heated to 55 ° C. with vigorous stirring. To this were added sodium pyrophosphate 0.5 part, ferrous sulfate 0.005 part, distilled water 5 parts, and polymerization was carried out at 55 ° C. for 8 hours to obtain a conjugated diene having a monomer conversion rate of 97% and a particle diameter of 0.08 μm. A rubbery polymer latex was obtained.

Synthesis of acid group-containing copolymer latex Potassium oleate 2.5 parts Potassium dioctyl sulfosuccinate 2.5 parts Disodium ethylenediaminetetraacetate 0.012 parts Ferrous sulfate 0.004 parts Rongalite 0.5 parts Distillation 200 parts of water The above composition was charged into a 5-liter glass separable flask, and the system was purged with nitrogen while stirring.
Temperature. A monomer mixture comprising 80 parts of n-butyl acrylate substituted with nitrogen, 20 parts of methacrylic acid and 0.5 part of cumene hydroperoxide was added dropwise thereto over 4 hours and polymerized. Thereafter, the mixture was further kept at 70 ° C. for 1 hour to obtain an acid group-containing copolymer latex having a monomer conversion rate of 97%.

Synthesis of Graft Copolymer [I-1 to 4] 10 parts (as solid content) of the above conjugated diene rubbery polymer latex are charged into a 20-liter separable flask. Next, 0.2 parts (as solid content) of the above-mentioned acid group-containing copolymer latex was added thereto with stirring, and the mixture was kept as it was for 30 minutes. An enlarged conjugated diene rubbery polymer latex having an average particle diameter of 0.36 μm was obtained.
To this was added a monomer mixture consisting of 40 parts of n-butyl acrylate 0.15 parts of allyl methacrylate 0.12 parts of t-butyl hydroperoxide and the amount of a crosslinking agent shown in Table 1 and sufficiently stirred. Thereafter, 0.2 part of sodium N-lauroyl sarcosinate and 3 parts of distilled water are charged, and the inside of the system is replaced with nitrogen to remove oxygen. When the internal temperature was raised to 45 ° C., the following composition was charged. After the polymerization was started and the internal temperature was raised to about 70 ° C., seed polymerization was performed while maintaining the mixture at 75 ° C. with stirring for 90 minutes. A small amount of the obtained latex was taken out, freeze-coagulated, separated and dried to evaluate and measure the gel content. Rongalit 0.25 parts Ferrous sulfate 0.0002 parts Disodium ethylenediaminetetraacetate 0.0006 parts Distilled water 3 parts

Further, the following composition was charged and heated to 75 ° C. while stirring. Sodium N-lauroyl sarcosinate 1.2 parts Rongalit 0.4 part Ferrous sulfate 0.001 part Disodium ethylenediaminetetraacetate 0.003 part Distilled water 10 parts Then, the following monomer mixture is added dropwise over 120 minutes. The mixture was charged to perform graft polymerization. After the dropping of the monomer mixture was completed, the mixture was kept for 1 hour with stirring to obtain a graft copolymer latex. This graft copolymer latex was poured into a dilute aqueous sulfuric acid solution to coagulate, and then dehydrated, washed and dried to obtain a powdery graft copolymer [I]. Acrylonitrile 15 parts Styrene 35 parts t-butyl hydroperoxide 0.3 parts n-octyl mercaptan 0.1 parts

Synthesis of maleimide copolymer [II-1] N-phenylmaleimide 20 parts Styrene 40 parts Acrylonitrile 20 parts Methyl ethyl ketone 20 parts 1,1'-azobis (cyclohexane-1-carbonitrile) 0.01 parts t- Dodecyl mercaptan 0.05 part The above mixture was continuously supplied to a 20-liter polymerization reactor equipped with a stirrer, which had been subjected to a nitrogen replacement operation, using a pump.
While maintaining the temperature in the polymerization reactor at 110 ° C., the polymerization reaction solution was continuously withdrawn by a gear pump provided at the bottom of the polymerization reactor so that the average residence time was 2 hours. After having been allowed to stay for about 20 minutes in a heat exchanger maintained at 150 ° C., it was introduced into a 2-vent type 30 mmφ twin-screw extruder in which the barrel temperature was controlled at 230 ° C. Atmospheric pressure in the first vent, 20 torr in the second vent
The volatile components were removed under a reduced pressure of r, and the mixture was pelletized with a pelletizer to obtain a maleimide-based copolymer [II-1]. The obtained maleimide-based copolymer contained 6% by weight of an oligomer component having a molecular weight of 200 to 1,000.

Synthesis of Maleimide Copolymer [II-2] 1,1'-azobis (cyclohexane-1-carbonitrile) was added in an amount of 0.18 to 95.degree.
And the same operation as in the synthesis of the maleimide-based copolymer [II-1], except that 0.22 parts by weight of t-dodecylmercaptan was used to obtain a pellet of the maleimide-based copolymer [II-2]. Was. The oligomer component having a molecular weight of 200 or more and 1000 or less contained in the obtained maleimide-based copolymer was less than 0.5% by weight.

Synthesis of copolymer [III] Acrylonitrile 30 parts Styrene 70 parts Azobisisobutyronitrile 0.15 parts t-dodecylmercaptan 0.6 parts Calcium phosphate 0.5 parts Distilled water 150 parts A liter autoclave was charged and stirred vigorously. After confirming the dispersion in the system, the temperature was raised to 75 ° C., and the polymerization was carried out for 3 hours. Thereafter, the temperature was raised to 110 ° C., and aging was performed for 30 minutes. Dehydration after washing, washing,
After drying, a beaded copolymer [III] was obtained. The weight average molecular weight measured by gel permeation chromatography (GPC) was 92,000 in terms of polystyrene.

[Examples 1 to 3 and Comparative Examples 1 to 3] Preparation of thermoplastic resin composition Predetermined amounts of graft copolymer [I], maleimide copolymer [II] and copolymer as shown in Table 1 Combined [III] was charged into a Henschel mixer with the following substances, and blended. ADK STAB AO-50 (made by Asahi Denka Kogyo Co., Ltd.) 0.3 parts ADK STAB PEP-36 (made by Asahi Denka Kogyo Co., Ltd.) 0.3 parts ADK STAB LA-63P (made by Asahi Denka Kogyo Co., Ltd.) 1 part Ethylene Bis-stearamide 1 part magnesium stearate 0.3 part silicon oil SH200 (manufactured by Toray Corning Silicone) 0.03 part
After melt-kneading at ℃, it was pelletized with a pelletizer.
The obtained pellets were injection molded to prepare various evaluation test pieces, and the physical properties were evaluated. Table 1 shows the results.

[0046]

[Table 1]

As is evident from Table 1, the thermoplastic resin composition of the present invention has excellent surface appearance (gloss) of a molded product in addition to weather resistance and heat resistance (Examples 1, 2 and 2). 3).
On the other hand, when the gel content of the rubber component in the graft copolymer [I] is low, the surface gloss decreases with a decrease in the gel content (Comparative Examples 1 and 2). This is because the surface of the molded plate was clouded or glossy. When a maleimide-based copolymer [II-2] containing almost no oligomer component was used as the maleimide-based copolymer [II] (Comparative Example 3), the resin composition containing a predetermined amount of the oligomer component (executed) Compared to Example 1), M which is an index of moldability
I is getting worse.

[0048]

As described above, the thermoplastic resin composition of the present invention has excellent properties such as excellent impact resistance, heat resistance, weather resistance, moldability, and excellent surface appearance of a molded article. And is extremely useful for applications such as automobiles, OA equipment, electricity, and electronic equipment.

Claims (1)

(57) [Claims] (A) a rubber component comprising one kind of a composite rubber of a conjugated diene-based rubbery polymer and an acrylate-based rubbery polymer, or a conjugated diene-based rubbery polymer and an acrylate-based rubber A rubber component composed of two kinds of a composite rubber with a styrenic polymer and an acrylate-based rubbery polymer in an amount of 40 to 70% by weight, and an unsaturated cyanide compound unit of 15 to 4
15 to 50 parts by weight of a graft copolymer [I] comprising 5% by weight and 60 to 30% by weight of a graft component comprising a copolymer of 85 to 55% by weight of an aromatic vinyl compound unit; A maleimide-based copolymer composed of 10 to 50% by weight of an aromatic compound unit, 35 to 80% by weight of an aromatic vinyl compound unit and 10 to 35% by weight of an unsaturated cyanide unit (the total amount of each component is 100% by weight) A maleimide-based copolymer which is a polymer and contains 2 to 10% by weight of an oligomer component having a molecular weight of 200 or more and 1000 or less containing a maleimide-based compound as an essential component in the maleimide-based copolymer [ II] 40 to 85 parts by weight, (C) a copolymer composed of 15 to 45% by weight of an unsaturated cyanide compound unit and 85 to 55% by weight of an aromatic vinyl compound unit [III] From 0 to 40 parts by weight (the total amount of components [I], [II] and [III] is 100 parts by weight) in the graft copolymer [I]. A thermoplastic resin composition, wherein the gel content of the rubber component (toluene-insoluble matter) is 85% by weight or more.