JP3163730B2 - Method for producing thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to heat resistance, moldability,
The present invention relates to a method for producing a thermoplastic resin composition which has excellent impact resistance and is useful for electric products, automobile parts and the like.

[0002]

2. Description of the Related Art Conventionally, research and development of a blend resin of a maleimide-based copolymer and a rubber-modified styrene-based thermoplastic resin such as an AS resin or an ABS resin (hereinafter sometimes referred to as a "maleimide-based copolymer composition"). Is being actively promoted. Since this maleimide copolymer composition is particularly excellent in heat resistance, it is used in automobile parts and home electric parts in place of parts in which a modified polyphenylene ether resin or the like is conventionally used due to insufficient heat resistance of ABS resin. Research and development are underway for the purpose. However, the maleimide-based copolymer composition has excellent heat resistance,
There is a drawback that the moldability and impact resistance are low, and particularly the practical impact strength is very low.

The inventors of the present invention have studied to solve the above problems, and as a result, the maleimide-based copolymer has a high glass transition temperature, and the difference from the glass transition temperature of the rubber-modified styrene-based thermoplastic resin to be compounded. It has been found that, because of the large size, the fact that both components are not sufficiently dispersed and compatible causes the impact strength to decrease. To make this dispersion compatibilization sufficient,
It has been attempted to use a twin-screw extruder, but the dispersion compatibilizing effect is still insufficient.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and a maleimide-based copolymer and a rubber-modified styrene-based thermoplastic resin are specified by using a twin-screw extruder. An object of the present invention is to provide a thermoplastic resin composition having excellent heat resistance, molding workability, and impact resistance by being extruded under the above temperature conditions.

[0005]

The present invention provides (A) (a-
1) 5 to 50% by weight of an N-substituted maleimide monomer, (a-
2) 10 to 95% by weight of an aromatic vinyl monomer, and (a)
-3) 0 to 40% by weight of a vinyl cyanide monomer [however,
(A-1) + (a-2) + (a-3) = 100% by weight]
Of a maleimide-based copolymer obtained by copolymerizing the above, and 95 to 20 parts by weight of (B) a rubber-modified styrene-based thermoplastic resin (provided that (A) + (B) = 100 parts by weight). Using a twin-screw extruder, the resin temperature during extrusion is set to +30 to 120 ° C. with respect to the cylinder set temperature,
Another object of the present invention is to provide a method for producing a thermoplastic resin composition, wherein the resin is extruded at a temperature of 230 to 330 ° C. at the time of extrusion.

First, the (a-1) N-substituted maleimide monomer used in the maleimide copolymer (A) is as follows:
Examples thereof include N-alkylmaleimide having 1 to 4 carbon atoms in the alkyl group, N-phenylmaleimide, N-substituted phenylmaleimide, and N-cyclohexylmaleimide. N-phenylmaleimide and N-cyclohexylmaleimide are preferred. (A-1) Examples of the N-substituted maleimide monomer include those obtained by copolymerizing maleic anhydride and imidizing with aniline or the like.

The aromatic vinyl monomer (a-2) used in the maleimide copolymer (A) includes styrene, α-methylstyrene, α-chlorostyrene, bromo
Styrene, p-methylstyrene and the like can be mentioned, and one kind or a mixture of two or more kinds is used. In particular, styrene, α
-Methylstyrene is preferred. Furthermore, (A-3) vinyl cyanide monomers used in the maleimide-based copolymer (A) include acrylonitrile, methacrylonitrile, maleonitrile and the like, and these may be used alone or in combination of two or more. Used as a mixture. In particular, acrylonitrile and methacrylonitrile are preferred.

The amount of the (a-1) N-substituted maleimide monomer used is 5 to 50% by weight, preferably 1%, in the component (A).
If it is less than 5% by weight, the effect of improving the heat resistance is small, while if it exceeds 50% by weight, the workability is reduced and it is not practical. (A-2) The amount of the aromatic vinyl monomer used is 10 to 95% by weight, preferably 20 to 85% by weight in the component (A). If it exceeds 95% by weight, the impact resistance decreases. (A-3) The amount of the vinyl cyanide monomer to be used is 0 to 40% by weight, preferably 5 to 35% by weight in the component (A). Absent. (A) The maleimide-based copolymer is (a-
It is obtained by copolymerizing monomer components containing 1) to (a-3) monomers, and the polymerization methods include emulsion polymerization, suspension polymerization, bulk polymerization, and solution polymerization. Used. The intrinsic viscosity (30 ° C. in methyl ethyl ketone) of the maleimide copolymer (A) used in the present invention is usually
0.3 to 0.9 dl / g.

Next, the rubber-modified styrene thermoplastic resin (B) used in the present invention is preferably an aromatic vinyl monomer or another vinyl monomer in the presence of a rubbery polymer. What is obtained by what is called a graft copolymerization prescription in which a monomer is graft-copolymerized is preferable.
Further, a rubber-modified styrene-based thermoplastic resin (graft copolymer) obtained by the graft copolymerization prescription is mixed with a styrene-based (co) polymer obtained by a separate method. A thing may be used.

Here, the rubbery polymer includes polybutadiene, styrene-butadiene copolymer, acrylic copolymer, hydrogenated diene copolymer, ethylene-propylene copolymer, chlorinated polyethylene, and polyurethane. Although polybutadiene is particularly preferred. (B) The preferred particle size of the rubber component of the rubber-modified styrene-based thermoplastic resin is at least 50% by weight of 1,200.
１，1,500Å, more preferably at least 70% by weight of 1,200〜2,500２ ，.

The aromatic vinyl monomer (B) used for the rubber-modified styrene-based thermoplastic resin may be the same as the component (a-2) used for the component (A). And preferably styrene, α-methylstyrene, bromostyrene and p-methylstyrene. Further, other copolymerizable vinyl monomers other than the aromatic vinyl monomer include N-substituted maleimide monomers similar to the component (a-1) used in the component (A), and (a) -3) In addition to the same vinyl cyanide monomer as the component, methyl methacrylate, maleic anhydride, methacrylic acid, methyl acrylate, ethyl acrylate, ethyl methacrylate and the like are used. (B) Resin component other than rubbery polymer of rubber-modified styrene-based thermoplastic resin (graft component + matrix component)
Preferably comprises an aromatic vinyl monomer and a vinyl cyanide monomer, and the composition ratio thereof is preferably 60 to 9
0/40 to 10 wt%, more preferably 65-85 /
35 to 15% by weight. Within this composition range, impact resistance is further improved.

Specific examples of the rubber-modified styrene-based thermoplastic resin (B) thus obtained include a conventional acrylonitrile-butadiene-styrene resin (ABS resin) and an acrylonitrile-ethylene-propylene-styrene resin (AES resin). And methyl methacrylate-butadiene-styrene resin (MBS resin), acrylonitrile-butadiene-methyl methacrylate-styrene resin (transparent ABS resin), and rubber-modified polystyrene (high impact polystyrene; HIPS). (B)
The rubber content in the rubber-modified styrene thermoplastic resin is preferably 5 to 40% by weight, more preferably 10 to 40% by weight.
３０30% by weight. The intrinsic viscosity [η] of the rubber-modified styrene-based thermoplastic resin (B) measured at 30 ° C. in methyl ethyl ketone is preferably 0.2 to 1.2 dl /.
g, more preferably 0.3 to 1.0 dl / g.
Further, the graft ratio measured by solvent fractionation using acetone or the like of the rubber component of the graft polymer in the rubber-modified styrene-based thermoplastic resin (B) is preferably 10 to 10.
It is 150%, more preferably 20 to 100%.

The thermoplastic resin composition of the present invention comprises the above components (A) and (B) as main components.
(A) 5 to 80 parts by weight, preferably 15 to 75 parts by weight, of a maleimide-based copolymer, (B) 95 to 20 parts by weight, preferably 85 to 25 parts by weight of a rubber-modified styrene-based thermoplastic resin [However, (A ) + (B) = 100 parts by weight].
When the amount of the component (A) is less than 5 parts by weight, the effect of improving heat resistance is insufficient. On the other hand, when the amount exceeds 80 parts by weight, processability is reduced and impact resistance is reduced.

According to the present invention, the above-mentioned components (A) and (B) are extruded by using a twin screw extruder, wherein the resin temperature at the time of extrusion is +30 to 120 ° C. with respect to the cylinder set temperature, By extruding at 230 to 330 ° C., a maleimide copolymer composition having excellent heat resistance, moldability and impact resistance is obtained. Here, the screw of the twin screw extruder used in the present invention is a disassembled part type, and has a structure in which the degree of kneading can be arbitrarily adjusted by assembling arbitrary screw parts. The assembling shape of the screw part is not particularly limited, but the screw part can be arbitrarily assembled so as to meet the extrusion temperature condition of the present invention. In addition, as for the rotation direction of this twin-screw extruder, the same direction is preferable because kneading is more effective and effective, but the opposite direction is also possible. When the components (A) and (B) of the present invention are extruded using a single-screw extruder, the dispersion compatibilization becomes insufficient and the impact strength is reduced.

Here, the cylinder set temperature of the twin-screw extruder in the present invention is an average set temperature of a set temperature below a hopper into which a raw material is charged and a set temperature other than a die head set temperature. Although the cylinder set temperature is not particularly limited, it is generally 180 to 260 ° C, preferably about 190 to 240 ° C. If the cylinder setting temperature is lower than 180 ° C., the load on the motor of the extruder is large, so that productivity is low. On the other hand, if the cylinder setting temperature is higher than 260 ° C., dispersion compatibilization may be insufficient.

The resin temperature is the temperature of the molten resin immediately before the die head of the extruder, and is usually measured by a temperature detector such as a thermocouple thermometer installed immediately before the die head. According to the extrusion temperature condition of the present invention, the resin temperature at the time of extrusion is from +30 to +
The temperature must be adjusted to 120 ° C, preferably +40 to + 90 ° C. If the temperature is lower than + 30 ° C., the degree of kneading is insufficient, so that the dispersion compatibilization is insufficient and a high impact strength cannot be obtained. On the other hand, if the temperature exceeds + 120 ° C., the decomposition of the rubber-modified styrene thermoplastic resin (B) starts, and Decrease and discoloration occurs. The resin temperature during extrusion is 230 to 330
° C, preferably 250-310 ° C. Is less than 230 ° C. decreased productivity, whereas if it exceeds 330 ° C. (B) starts decomposition of the rubber-modified styrene thermoplastic resins, the impact strength results in a color change decreases.

The thermoplastic resin composition of the present invention thus obtained has a heat distortion temperature of 95 ° C. or more, preferably 95 to 135 ° C., and a falling weight impact strength of 80 kg · cm or more, Preferably 80 to 200 kg · c
m and excellent in heat resistance and impact resistance.

The thermoplastic resin composition of the present invention contains the above-mentioned components (A) and (B) as main components, and may further contain a lubricant, an antistatic agent, an antioxidant, a flame retardant, an ultraviolet ray, if necessary. It is possible to mix an inorganic filler such as an absorbent, a photooxidant, a colorant, and glass fiber, or a compounding agent or an additive generally used in this type of thermoplastic resin composition.

[0019]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof. In the examples, parts and% are based on weight unless otherwise specified.
Various measurements in the examples were based on the following methods. Physical properties of a test piece injection molded at an Izod impact strength and a heat deformation temperature of 260 ° C. were measured under the following conditions. Izod impact strength; ASTM D256 (1/4 ")
(Notched). The unit is kg · cm /
cm. Heat distortion temperature; ASTM D648 (1/2 ", 18.6)
kg / cm ² ). The unit is ° C. Melt flow rate (MFR ) Measured at 240 ° C. under a load of 10 kg according to JIS K7210. The unit is g / 10 minutes. Practical impact strength A DuPont type falling weight impact strength was measured using a molded plate having a thickness of 2.4 mm. The unit is kg · cm. The yellow index was measured according to ASTM D1925 (thickness: 3 mm).

Reference Example 1 [(A) Preparation of maleimide copolymer] In a 5 liter reactor equipped with a stirrer and a plate baffle, 50 parts of pure water and 0.2 parts of potassium persulfate were charged. After replacing the inside of the vessel with nitrogen gas,
The temperature was raised to 0 ° C. To this reactor, a mixture of 0.1 part of t-dodecylmercaptan, 1 part of sodium dodecylbenzenesulfonate, 100 parts of pure water and the monomers shown in Table 1 was continuously added over 5 hours. Thereafter, the temperature was raised to 80 ° C. and aging was performed for 2 hours to obtain a latex. An aqueous calcium chloride solution was added to the obtained copolymer latex for coagulation treatment, and the product was recovered.

[0021]

[Table 1]

Reference Example 2 [(B) Preparation of Rubber-Modified Styrenic Thermoplastic Resin] ABS Resin 1; 40 parts of polybutadiene rubber and 4 parts of styrene
A graft copolymer obtained by graft polymerization of 5 parts and 15 parts of acrylonitrile. Graft ratio = 50%, [η] (Intrinsic viscosity of methyl ethyl ketone soluble matter) = 0.5 dl / g AS resin 1: 75 parts of styrene and acrylonitrile 2
AS resin consisting of 5 parts. [Η] (Intrinsic viscosity of methyl ethyl ketone soluble matter) = 0.6 dl / g

Examples 1 to 7 and Comparative Examples 1 to 8 The components (A) and (B) were mixed with a Henschel mixer according to the formulation shown in Tables 2 and 3, and a twin screw extruder manufactured by Toshiba Machine Co., Ltd. Using (TEM-50A), granulation was performed under the extrusion temperature conditions shown in Tables 2 and 3. The screw parts were assembled using an IBC-2-2 model designated by Toshiba Machine Co., Ltd. The results are shown in Tables 2 and 3.

Examples 1 to 7, which are the compositions of the present invention, have good physical properties, practical impact strength and yellow index. On the other hand, in Comparative Examples 1 and 2, the difference between the cylinder set temperature and the resin temperature is small, and the extrusion temperature condition of the present invention is deviated, and the practical impact strength is greatly reduced. Comparative Example 3 is a case where the resin temperature exceeds the range of the present invention, the practical impact strength is largely reduced, and the yellow index is also deteriorated. Comparative Example 4 is a case where the difference between the resin temperature, the cylinder set temperature and the resin temperature is also out of the range of the present invention, and the practical impact strength is greatly reduced and the yellow index is also deteriorated. Comparative Example 5 is (A)
This is the case where the amount of the component is too large, and the impact strength, moldability and the like are inferior. Comparative Example 6 constitutes the component (A) (a-
1) Low N-substituted maleimide monomer, impact strength,
Poor heat resistance. In Comparative Example 7, the amount of the (a-1) N-substituted maleimide monomer was too large, and the moldability was poor. Comparative Example 8
The component (A) (a-3) is a case where the amount of the vinyl cyanide monomer is too large, and the yellow index (heat discoloration resistance) is poor. From the above results, it can be seen that the thermoplastic resin composition of the present invention is excellent in heat resistance, moldability and impact strength, and has extremely high industrial significance.

[0025]

[Table 2]

[0026]

[Table 3] *) Measurement is not possible

[0027]

According to the present invention, the maleimide copolymer and the rubber-modified styrenic thermoplastic resin are mixed by using the method shown in the present invention to obtain not only heat resistance and molding processability but also particularly A more excellent impact resistance thermoplastic resin composition can be obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takeki Furuyama 2-11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd. (56) References JP-A-4-7345 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 35/06

Claims (1)

(57) [Claims] (A) (a-1) 5 to 50% by weight of an N-substituted maleimide monomer, (a-2) aromatic vinyl monomer 1
0 to 95% by weight, and (a-3) 0 to 40% by weight of a vinyl cyanide monomer [however, (a-1) + (a-2) +
(A-3) = 100% by weight], and 5 to 80 parts by weight of a maleimide-based copolymer obtained by copolymerizing (A) 95 to 20 parts by weight of a rubber-modified styrene-based thermoplastic resin (provided that (A) + (B) = 100 parts by weight] using a twin-screw extruder to extrude the resin at a temperature of +30 to 120 ° C. and a temperature of 230 to 330 ° C. at the time of extrusion with respect to the cylinder set temperature. A method for producing a thermoplastic resin composition, comprising: