JP2002037974A - Vehicle exterior material highly resistant to chipping and impact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vehicle exterior material high in chipping resistance with the rupture cross-section ductile rather than representing a sharp edge when broken by molding a rubber-reinforced styrene-based resin. SOLUTION: This vehicle exterior material is obtained by compounding a rubber-reinforced styrene-based resin with a thermoplastic elastomer so as to adjust both the tanδ peak height and peak temperature in the viscoelastic properties of the final exterior material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle exterior material obtained by molding a rubber-reinforced styrenic resin composition, and is suitable for use as a foil cap, a radiator grill, a side mudguard, an aero part, a side protector part, and the like. The present invention relates to exterior materials for vehicles with excellent impact resistance. Furthermore, it has excellent chipping resistance, and its molded product has ductility without a sharp edge (sharp edge) at the time of collision, and has heat deformation resistance. And high exterior materials for vehicles.

[0002]

2. Description of the Related Art ABS resin (acrylonitrile-butadiene-styrene resin) has excellent impact resistance, heat deformation resistance, and moldability, so that it is used for exterior materials of automobiles, housing parts of home appliances and OA equipment. Widely used for. In recent years, especially for exterior materials of automobiles, along with characteristics such as dimensional stability at high temperatures and surface appearance, the fracture surface must not become a sharp edge at the time of collision. Security is required. Furthermore, chipping resistance is also required from the viewpoint of noise in automobiles.

[0003] Various studies have been made to satisfy these characteristics, but none of them has yet been obtained having sufficient characteristics. For example, JP-A-3-45646 discloses a method in which a block copolymer having a specific structure is added to a rubber-reinforced styrene-based resin. However, in these compositions, the fracture surface of a molded article is ductile. However, a resin composition having high heat deformation resistance and excellent moldability has not been obtained.

Further, a method of improving impact resistance by focusing on the rubber particle size distribution of a styrene resin has been proposed. For example, in Japanese Patent Application Laid-Open Nos. 8-13412 and 8-134316, there is a combination of small particle size rubber and medium particle size rubber. But,
In these compositions, the fracture surface of the molded article is ductile,
In addition, a resin composition having high heat deformation resistance, excellent moldability, and taking into account NVH characteristics (Noise Vibration Harshness), that is, chipping noise related to occupant comfort, has not been obtained.

[0005]

A polymer material is originally an advantageous material in terms of suppressing the generation of vibration and noise as compared with a metal material, but a general-purpose rubber-reinforced styrene resin is used as a vehicle exterior material. When the rocking sound, that is, the chipping sound, was measured in an automobile, it was not satisfactory in terms of noise. The present invention, as a vehicle exterior material, eliminates chipping properties at around normal temperature, and furthermore, the molded product has a ductile surface without a sharp edge, and has a high heat-resistant deformation property, and has a high formability. An object of the present invention is to provide a vehicle exterior material obtained by molding an excellent thermoplastic resin composition.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the problems of the rubber-reinforced styrenic resin, and as a result, blended a thermoplastic elastomer with the rubber-reinforced styrenic resin and examined its viscoelasticity. By adjusting
Also, a specific small particle size rubber-containing graft copolymer (A), a medium particle size rubber-containing graft copolymer (B) and a styrene-based copolymer (C) are blended in a specific ratio to contain a large amount of rubber. The resin composition further containing a specific thermoplastic elastomer has a peak height of the specific viscoelasticity loss tangent (tan δ) of 0.015 or more and a peak temperature of -40 to 40. It has been found that the condition of 50 ° C. is satisfied, the fracture surface of the molded product does not become a sharp edge, it becomes ductile fracture, the heat resistance is high, and the resin composition itself is also excellent in moldability. Reached.

That is, according to the present invention, the thermoplastic elastomer 1 to 100 parts by weight of the rubber-reinforced styrene resin is used.
30 parts by weight of a resin composition having a loss tangent (tan δ) peak height of 0.0
A vehicle exterior material (Claim 1) and a rubber-reinforced styrene resin obtained by molding a resin composition having a peak temperature of −40 to 50 ° C. and having a volume average particle diameter of (A) of 60 or more 10 to 90% by weight of an aromatic vinyl compound in the presence of 15 to 90 parts by weight of a diene rubber polymer, an acrylic rubber polymer, a silicon rubber polymer or an olefin rubber polymer (Ra) 10) 90% by weight of acrylic acid ester monomer or vinyl cyanide monomer
And a graft copolymer obtained by polymerizing 10 to 85 parts by weight of a monomer mixture composed of 0 to 30% by weight (total 100% by weight) and a monomer copolymerizable therewith (100 parts by weight in total with a rubber polymer). 2 to 40 parts by weight of polymer, (B) 15 to 90 parts by weight of diene rubber polymer, acrylic rubber polymer, silicon rubber polymer or olefin rubber polymer (Rb) having a volume average particle diameter of 260 to 1000 nm. 10 to 90% by weight of an aromatic vinyl monomer, 10 to 90% by weight of a (meth) acrylate monomer or a vinyl cyanide monomer and a monomer 0 to 10 30% by weight
(Total 100% by weight)
20 to 68 parts by weight of a graft copolymer obtained by polymerizing parts by weight (100 parts by weight in combination with the rubber polymer), (C) 10 to 40% by weight of a vinyl cyanide monomer, aromatic vinyl or maleimide 5 to A monomer mixture consisting of 80% by weight and 0 to 30% by weight (total 100% by weight) of monomers copolymerizable therewith is polymerized, and the reduced viscosity (30 ° C., N, N 0 to 78 parts by weight of a styrene copolymer having a dimethylformamide solution of 0.1 to 1.2 dl / g and (D) a weight average molecular weight of 1000
0 to 35,000 parts by weight of an aromatic polycarbonate of 0 to 35000 [(A), (B), (C) and (D) 100
Part by weight], wherein the exterior material for vehicles (Claim 2) according to claim 1 and the rubber polymer (Rb) of the graft copolymer (B) are an acid group-containing polymer latex. The vehicle exterior material according to claim 2, wherein the exterior material is a rubber polymer that has been enlarged by using a rubber polymer.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The rubber-reinforced styrene-based resin of the present invention is a styrene-based resin whose impact resistance has been increased by using a rubber component. Specific examples include ABS resin and AES.
Resin and AAS resin. Further, a thermoplastic resin composition containing these compounds is also included. The thermoplastic elastomer of the present invention behaves as a rubber elastic body at room temperature, but is a polymer that undergoes plastic deformation with an increase in temperature. Among them, a styrene-isoprene-styrene (SIS) block copolymer, Styrene-isoprene (SI) block copolymer, hydrogenated styrene-isoprene-styrene (hydrogenated SIS) block copolymer, hydrogenated styrene-isoprene (hydrogenated SI) block copolymer, styrene-isobutylene-styrene (SIBS) ) Block copolymers, isoprene-isobutylene copolymers, chloroprene polymers, norbornene polymers, polyurethanes,
(Meth) acrylic acid ester-based resin, (meth) acrylic acid ester-acrylonitrile copolymer, acrylonitrile-butadiene rubber (NBR) and the like are preferable, and are selected from these in consideration of the correlation with the base resin. . That the fracture surface of the molded product does not become sharp edge,
And styrene-isoprene-
Styrene (SIS) block copolymers and / or hydrogenated styrene-isoprene-styrene (hydrogenated SIS) block copolymers and (meth) acrylate-acrylonitrile copolymers are preferred.

The selected thermoplastic elastomer has a peak height of tan δ of the material of 0.015 or more,
It is blended so that the peak temperature becomes -40 to 50C. When the tan δ value of the material is high, micro-Brownian motion is promoted between the segments of the formed polymer material, and the sound energy is converted to heat energy by dynamic heat generation, thereby silencing the sound.

[0010] Further, the rubber-reinforced styrenic resin comprises (A)
In the presence of 15 to 90 parts by weight of a diene rubber polymer, acrylic rubber polymer, silicon rubber polymer or olefin rubber polymer (Ra) having a volume average particle diameter of 60 to 250 nm, the aromatic vinyl compound 10 is used. 90% by weight, (meta)
Acrylic ester monomer or vinyl cyanide monomer 1
0 to 90% by weight and monomers 0 to 3 copolymerizable therewith
Monomer mixture 1 consisting of 0% by weight (total 100% by weight)
0 to 85 parts by weight (100 parts by weight in combination with the rubber polymer)
2 to 40 parts by weight of a graft copolymer obtained by polymerizing
(B) aromatic vinyl in the presence of 15 to 90 parts by weight of a diene rubber polymer, acrylic rubber polymer, silicone rubber polymer or olefin rubber polymer (Rb) having a volume average particle diameter of 260 to 1000 nm; 10 to 90% by weight of monomer,
A monomer mixture 10 to 90% by weight of a (meth) acrylate monomer or a vinyl cyanide monomer and 0 to 30% by weight of a monomer copolymerizable therewith (total 100% by weight). 85 parts by weight (100 in total with rubber polymer)
20 to 68 parts by weight of a graft copolymer obtained by polymerizing (C) a vinyl cyanide monomer by 10 to 40% by weight,
A monomer mixture comprising 5 to 80% by weight of an aromatic vinyl or maleimide and 0 to 30% by weight of a copolymerizable monomer (total 100% by weight) is polymerized, and the reduced viscosity of a methyl ethyl ketone soluble component is reduced. (D) an aromatic polycarbonate having a weight average molecular weight of 10,000 to 35,000 and (D) a weight average molecular weight of 10,000 to 35,000 (30 ° C., in N, N-dimethylformamide solution) 0.1 to 1.2 dl / g A rubber-reinforced styrene resin composed of 0 to 45 parts by weight [100 parts by weight in total of (A), (B), (C) and (D)] is also excellent in moldability and is preferable.

[0011] The graft copolymer in the resin composition of the present invention comprises a graft copolymer (A) using a specific small particle diameter rubber and a graft copolymer (B) using a medium particle diameter rubber.
Is preferably present in the above-mentioned specific ratio, and when only the graft copolymer (A) or the graft copolymer (B) alone is used, the fracture surface of the molded article tends to be more ductile and not have sharp edges.

The rubber polymer (Ra) in the small particle size rubber-containing graft copolymer (A) has a volume average particle size of 6
Although it is 0 to 250 nm, the more preferable volume average particle size is 60 to 160 nm in that the fracture surface of the molded article is more ductile and does not have a sharp edge. When the volume average particle size is less than 60 nm or more than 250 nm, the fracture surface of the molded article is ductile and easily becomes a sharp edge.

The volume average particle diameter of the rubber polymer (Rb) in the rubber-containing graft copolymer (B) having a medium particle diameter is 2
It is preferably from 60 to 1000 nm, and more preferably produced by a coagulation enlargement method using an acid group-containing copolymer latex, and more preferably a volume average particle diameter from the viewpoint that the fracture surface of the molded article is ductile and does not have a sharp edge. Is 300 ~
It is 800 nm. If the volume average particle size is less than 260 nm or more than 1000 nm, the fracture surface of the molded article is ductile, easily becomes a sharp edge, and the moldability is reduced. Further, the volume average particle size distribution of the rubber polymer in the thermoplastic resin composition of the present invention was observed in a transmission electron microscope analysis-image analysis method (TEM method) and found to be in a range of 5 to 80 nm in a range of 60 to 250 nm. %, 95-2 in the range of 260-1000 nm
More preferably, it is 0% by weight.

The rubber polymers (Ra), (R)
As b), diene rubber polymers such as butadiene rubber and styrene-butadiene rubber, butyl acrylate rubber,
Butadiene-butyl acrylate rubber, 2-ethylhexyl acrylate-butyl acrylate rubber, methacrylic acid 2
-Acrylic rubber polymers such as ethylhexyl-butyl acrylate rubber, stearyl acrylate-butyl acrylate rubber, composite rubber polymers such as silicon / butyl acrylate, and olefin rubbers such as ethylene-propylene rubber and ethylene-propylene-diene rubber Examples thereof include polymers and silicone rubber polymers such as polydimethylsiloxane rubber, and these may be used alone or in combination of two or more.

[0015] The enlargement of latex rubber particles by the coagulation enlargement method using an acid group-containing copolymer latex is particularly effected by using acrylic acid, methacrylic acid, itaconic acid, crotonic acid with respect to 100 parts by weight (solid content) of rubber latex. 5 to 50% by weight of at least one unsaturated acid selected from the group consisting of:
50 to 95% by weight of at least one (meth) alkyl acrylate having 1 to 12 carbon atoms in an alkyl group, and an acid group-containing prepared by polymerizing 0 to 40% of a monomer copolymerizable therewith. A molded article obtained by a coagulation enlargement method using a copolymer latex is more preferred in that it has a high impact resistance.

The monomer mixture in the graft copolymer (A) and the graft copolymer (B) is 10 to 90% by weight of an aromatic vinyl monomer, a (meth) acrylate monomer, A total of 100% by weight of 10 to 90% by weight of at least one compound of vinyl monomer and 0 to 30% by weight of a monomer copolymerizable therewith does not have a sharp edge in the molded product. From the viewpoint of moldability, the aromatic vinyl monomer is more preferably 20 to 8
5% by weight, 15 to 80% by weight of a (meth) acrylate monomer and a vinyl cyanide monomer, and 0 to 20% by weight of a monomer copolymerizable therewith, more preferably aromatic 25 to 85% by weight of a vinyl monomer, 15 to 15% of a (meth) acrylate monomer, and a vinyl cyanide monomer.
75% by weight and 0 to 10 of a monomer copolymerizable therewith.
% By weight. If the amount of the aromatic vinyl monomer is less than 10% by weight, the processability is deteriorated, and if it exceeds 90% by weight, the fracture surface of the molded article becomes a sharp edge and the moldability is also reduced.

Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, p-methylstyrene, p-isopropylstyrene, chlorostyrene, bromostyrene and the like. Examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile.
Examples of the (meth) acrylate compound include methacrylate having an alkyl group having 1 to 18 carbon atoms such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate, methyl acrylate, ethyl acrylate, and butyl. Acrylates having an alkyl group having 1 to 18 carbon atoms, such as acrylate, 2-ethylhexyl acrylate, and stearyl acrylate, are exemplified. Other copolymerizable monomers include:
(Meth) acrylic acid derivatives other than (meth) acrylic acid esters such as (meth) acrylic acid and glycidyl (meth) acrylate, and maleimide compounds such as maleimide and N-phenylmaleimide. They are,
One type or two or more types may be used.

The styrene copolymer (C) is 10 to 40% by weight of a vinyl cyanide monomer, 5 to 80% by weight of an aromatic vinyl monomer and / or a maleimide monomer, and is copolymerizable therewith. Monomer is 0 to 30% by weight in total 100
% By weight, and more preferably from 15 to 37% by weight of a vinyl cyanide monomer, from 15 to 37% by weight of an aromatic vinyl monomer and / or a maleimide monomer.
80% by weight, and 0 to 1 of a monomer copolymerizable therewith.
5% by weight.

Examples of the vinyl cyanide monomer include acrylonitrile and methacrylonitrile. As maleimide, maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide,
N-butylmaleimide, N-phenylmaleimide, N-
(P-methylphenyl) maleimide and the like. Further, the reduced viscosity (30 ° C., in N, N-dimethylformamide solution) of the methyl ethyl ketone soluble portion of the styrene copolymer (C) is 0.1 to 1.2 dl / g, more preferably 0.2 to 1.2 dl / g. 0.9 dl / g. If it is less than 0.1 dl / g, the fracture surface of the molded article becomes a sharp edge, and
If it exceeds dl / g, workability tends to decrease.

The aromatic polycarbonate (D) has a weight-average molecular weight of 10,000 to 35,000, but more preferably has a weight-average molecular weight of 2,000 in view of the fact that the fractured surface of the molded product does not have sharp edges and the molding processability.
0 to 32,000. If the weight average molecular weight is less than 10,000, the fracture surface of the molded article tends to have sharp edges. If the weight average molecular weight exceeds 35,000, the moldability tends to decrease.

The thermoplastic resin composition according to the present invention comprises the rubber-containing graft copolymer (A) 2
40 parts by weight, more preferably 2 to 30 parts by weight, medium-particle size rubber-containing graft copolymer (B) 20 to 68 parts by weight, more preferably 30 to 60 parts by weight, styrene-based copolymer (C) 0 to 0 A thermoplastic resin composition comprising a total of 100 parts by weight of 78 parts by weight, more preferably 0 to 70 parts by weight, 0 to 45 parts by weight of aromatic polycarbonate (D), and more preferably 0 to 35 parts by weight; Is 2 in the resin composition
A thermoplastic resin composition of 0 to 50% by weight is preferred.
Outside the above range, the moldability tends to decrease, and the fracture surface of the molded article tends to have sharp edges.

In the thermoplastic resin composition of the present invention, the total content of the rubber polymers (Ra) and (Rb) is preferably 20 to 50% by weight, more preferably 25% by weight in the resin composition.
~ 45% by weight. Rubber content of 20 in the resin composition
When the amount is less than 50% by weight, the fracture surface of the molded article becomes a sharp edge, and when the amount exceeds 50% by weight, the moldability tends to decrease. The graft copolymer (A), the graft copolymer (B) and the styrene-based copolymer (C) may be produced by any polymerization method. For example, a known bulk polymerization method, a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, an emulsion-suspension polymerization method, an emulsion-bulk polymerization method, and the like can be controlled by any polymerization method as long as the composition can be controlled within the scope of the present invention. May be done. For the graft copolymers (A) and (B), an emulsion polymerization method is preferred because the graft ratio is easily controlled.

The graft copolymer (A), the graft copolymer (B) and the styrene copolymer (C) may be those produced using any initiator, chain transfer agent and emulsifier. Known initiators such as a thermal decomposition initiator such as potassium persulfate and a redox initiator such as Fe-reducing agent-organic peroxide can be used as the initiator. Known chain transfer agents such as t-dodecyl mercaptan, n-dodecyl mercaptan, α-methylstyrene dimer and terpinolene can be used. Examples of the emulsifier include fatty acid metal salt-based emulsifiers such as sodium oleate, sodium palmitate, and sodium rosinate, sodium dodecylbenzenesulfonate, and having 12 to 12 carbon atoms.
Known emulsifiers such as a sodium sulfonic acid metal salt-based emulsifier such as 20 alkyl sodium sulfonate and sodium dioctyl sulfosuccinate can be used.

[0024] The thermoplastic resin composition of the present invention comprises
It is also possible to further blend with S resin, polyamide resin, PET resin and PBT resin for use. In addition, commonly known antioxidants, heat stabilizers, UV absorbers, pigments, antistatic agents, and lubricants can be used as needed.
In particular, phenol-based, sulfur-based, phosphorus-based, hindered amine-based stabilizers, antioxidants, benzophenone-based, benzotriazole-based ultraviolet absorbers and organopolysiloxanes used in styrene resins, aliphatic hydrocarbons,
Lubricants such as esters of higher fatty acids and higher alcohols can be used as molding resins for higher performance. These stabilizers and lubricants can be used alone or in combination of two or more.

The thermoplastic resin composition of the present invention varies depending on the method for producing the graft copolymers (A), (B) and the styrene-based copolymer (C). , Pellets, or the like, or a combination thereof. Graft copolymer (A), (B), styrene copolymer (C)
When recovering the polymer powder from the latex, the usual method, for example, the latex calcium chloride, magnesium chloride, salts of alkaline earth metals such as magnesium sulfate, sodium chloride, salts of alkali metals such as sodium sulfate, hydrochloric acid , Sulfuric acid, phosphoric acid, after coagulating the latex by adding inorganic and organic acids such as acetic acid,
Dehydration and drying can be performed. Also, a spray drying method can be used. Further, a part of the amount of the stabilizer used may be added to a latex or slurry of these resins in the form of a dispersion.

Further, the thermoplastic resin composition of the present invention comprises a graft copolymer (A), a graft copolymer (B), a styrene copolymer (C), and an aromatic polycarbonate (D).
(A), (B), (C) and (D) are combined with 1 to 30 parts by weight of a thermoplastic elastomer and, if necessary, stabilizers, lubricants, pigments, etc., based on 100 parts by weight, Kneading can be carried out by a known melt kneading machine such as a remixer, a roll mill, a single screw extruder, and a twin screw extruder.

The thermoplastic resin composition of the present invention can be processed into a molded product by a known processing method such as injection molding, extrusion molding, vacuum molding, blow molding and the like. In addition, the thermoplastic resin composition of the present invention has ductility in which the fracture surface of the molded article is not sharp edges, is ductile, has high heat deformation resistance, is excellent in moldability, and has a peak height of loss tangent (tan δ). Is 0.0
It is used for parts that can effectively exhibit the characteristics of 15 or more and a peak temperature of -40 to 50 ° C. In particular, wheel caps, radiator grills, side mudguards, aero parts, side protector parts which are exterior materials for vehicles And so on.

[0028]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but these are merely examples, and the present invention is not limited thereto. Unless otherwise noted,
"Parts" represents parts by weight, and "%" represents% by weight.

Production of rubber-reinforced styrene resin (1) Production of rubber-containing graft polymer (A) having small particle diameter (1-1) Production of polybutadiene By a known method, a rubber latex (a- 1) was obtained. The volume average particle diameter of the latex was determined by taking a transmission electron microscope photograph by osmium tetroxide staining method, measuring the particle diameter of 500 to 1000 rubber-like dispersed particles, and calculating the average particle diameter. When the particles were elliptical, the average value of the major axis a and the minor axis b, that is, (a + b) / 2 was defined as the particle diameter.

(1-2) Production of Graft Polymer (A) Containing Small Particle Diameter Rubber The substances shown in Table 1 below were placed in a reactor equipped with a stirrer, reflux condenser, nitrogen inlet, monomer inlet, and thermometer. And the temperature was raised to 60 ° C. in a nitrogen stream while stirring the reactor.

Pure water 200 parts Rubber-like polymer (solid content) Types and amounts described in Table 1 Sodium formaldehyde sulfoxylate 0.2 parts EDTA 0.01 parts Ferrous sulfate 0.0025 parts Reached 60 ° C After that, the monomer mixture shown in Table 1 was continuously added dropwise over 4 hours, and after completion, the polymerization was terminated by continuing stirring at 60 ° C. for 1 hour, and the graft copolymer (A-1) and (A −
2) was obtained.

[0032]

【table 1】 (2) Production of rubber-containing graft copolymer (B) having medium particle size (2-1) Production of acid group-containing copolymer latex An acid group-containing copolymer latex for enlargement was produced as follows. First, the following substances were charged into a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, a monomer inlet, and a thermometer.

Pure water 200 parts Dioctyl sodium sulfosuccinate 0.5 parts Sodium formaldehyde sulfoxylate 0.3 parts The temperature was raised to 70 ° C. under a nitrogen stream while stirring the reactor.
After reaching 70 ° C., the following components were continuously added dropwise over 1.5 hours.

BA (butyl acrylate) 24 parts MAA (methacrylic acid) 1 part tDM (t-dodecyl mercaptan) 0.1 part CHP (cumene hydroperoxide) 0.03 part Subsequently, the following components were continuously added. The mixture was added dropwise for 3.5 hours, and after completion, the polymerization was completed by continuing stirring at 65 ° C. for 1 hour.

BA 3 parts BMA (butyl methacrylate) 58 parts MAA 14 parts tDM 0.3 parts CHP 0.08 parts (2-2) Enlargement treatment Polybutadiene rubber (a-1) 1 obtained in (1-1) above
After adding 3 parts of the acid group-containing latex obtained in (2-1) at a time to 00 parts by weight, stirring was continued for 1 hour to complete the enlargement, and the polybutadiene rubber latex (b-1) having a volume average particle size of 470 nm was obtained. ) Got.

Similarly, after adding 4 parts of the acid group-containing copolymer latex obtained in the above (2-1) all at once, stirring was continued for 1 hour to complete the enlargement, and the polybutadiene rubber having a volume average particle diameter of 350 nm was obtained. Latex (b-2) was obtained. The volume average particle size of the latex was determined by taking a transmission electron micrograph by osmium tetroxide staining method,
The average particle diameter was determined by measuring the particle diameter of 00 to 1000 particles. When the particles were elliptical, the average value of the major axis a and the minor axis b, that is, (a + b) / 2 was defined as the particle diameter.

(2-3) Production of Graft Polymer (B) Containing Rubber with Medium Particle Diameter The following substances were charged into a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, a monomer inlet, and a thermometer. The reactor was heated to 60 ° C. under a nitrogen stream while stirring.

Pure water 200 parts Rubber-like polymer (solid content) Kind and amount described in Table 2 Sodium formaldehyde sulfoxylate 0.2 parts EDTA 0.01 parts Ferrous sulfate 0.0025 parts The temperature reached 60 ° C. Thereafter, the monomer mixture shown in Table 2 was continuously added dropwise over 4 hours. After completion, stirring was continued at 60 ° C. for 1 hour to terminate the polymerization, thereby obtaining a graft copolymer (B-1).

[0039]

[Table 2] (3) Production of styrenic copolymer (C) In a reactor equipped with a stirrer, a reflux condenser, a nitrogen inlet, a monomer inlet, and a thermometer, the following substances and the monomers (I) shown in Table 3 were used. And stirring the reactor under a nitrogen stream.
The temperature was raised to 5 ° C.

Pure water 200 parts Dioctyl sodium sulfosuccinate 1 part Sodium formaldehyde sulfoxylate 0.4 parts EDTA 0.01 parts Ferrous sulfate 0.0025 parts After reaching 65 ° C., the monomers shown in Table 3 were added. It was dripped continuously for 6 hours. Also, 0.5 part of sodium dioctyl sulfosuccinate was added at the first hour of polymerization and 0.5 part at the third hour.
Part added. After completion of the dropwise addition, stirring was continued at 65 ° C. for 1 hour to terminate the polymerization, and the styrene-based copolymer (C-1), (C-
2), (C-3) and (C-4) were obtained.

[0041]

[Table 3] Description of abbreviations BA: butyl acrylate BMA: butyl methacrylate St: styrene PMI: N-phenylmaleimide MAA: methacrylic acid tDM: t-dotecilmercaptan CHP: cumene hydroperoxide EDTA: disodium ethylenediaminetetraacetate PBd: polybutadiene αMSt: α -Methylstyrene AN: Acrylonitrile PMI: N-phenylmaleimide (4) Production of thermoplastic resin composition (E) Small particle size rubber-containing graft copolymer (A), medium particle size rubber-containing graft copolymer produced above A thermoplastic elastomer was blended in a ratio shown in Table 4 with respect to a total of 100 parts by weight of the polymer (B), the styrene-based copolymer (C), and the aromatic polycarbonate (D).
0.3 parts of P-24G, phenolic stabilizer A0-20
And 0.3 parts (both manufactured by Asahi Denka Kogyo Co., Ltd.) were blended uniformly, and uniformly blended with a 201 blender manufactured by Tabata. Next, pellets were produced by melt-kneading with a 40 mm single screw extruder manufactured by Tabata Co., Ltd. From the obtained pellets, molding was performed at a cylinder temperature of 250 to 270 ° C. using a 100B injection molding machine manufactured by FANUC CORPORATION to prepare test pieces necessary for physical property evaluation. The evaluation results are shown in Tables 4 and 5. Indicated. D component: Teflon A220 manufactured by Idemitsu Petrochemical Co., Ltd.
0: An aromatic polycarbonate having a weight average molecular weight of 27,700 was used. SIS: Styrene-isobrene-styrene block high blur 5127 manufactured by Kureha Co., Ltd. was used as the thermoplastic elastomer. Hydrogenated SIS: A hydrogenated styrene-isobrene-styrene block hybler 7125 manufactured by Kureha Corporation was used. NAR: butyl acrylate-nitrile rubber (AN content 25%) was used.

[0042]

[Table 4]

[0043]

[Table 5] (5) Evaluation (5-1) Fracture surface of molded article In an atmosphere of 23 ° C, a molded article of an aero part for vehicle exterior having a shape shown in FIG. It was observed whether the fractured surface was ductile (not a sharp edge) or brittle (a sharp edge). It is preferable for the chipping property to have a ductile fracture surface instead of a brittle one. (5-2) Heat resistance (HDT) The heat resistance was evaluated at a heat deformation temperature of 18.6 kg / cm ² load according to ASTM D-648. (Unit: ° C) (5-3) Formability (SPL: Spiral flow) Using a 100B injection molding machine manufactured by FANUC CORPORATION, cylinder temperature 250 ° C, injection pressure 1350 kg / cm ²
The evaluation was made based on the flow length of the resin in a spiral mold having a thickness of 3 mm. (Unit: mm) (5-4) Measurement of viscoelastic spectrum (tan δ) A bar of 5 mm × 50 mm × 2 mm was prepared, and using a DMS110 manufactured by Seiko Denshi Co., Ltd., the bending mode and tan δ at a frequency of 100 Hz were −60. The temperature was measured in the range of １００100 ° C., and the peak temperature and the peak height were measured.

[0044]

According to the thermoplastic resin composition of the present invention, the fracture surface of a molded article is ductile without sharp edges,
Moreover, it is a thermoplastic resin composition having high heat deformation resistance and excellent moldability. Therefore, it is particularly suitable for wheel caps, radiator grills, side mud guards, aero parts, side protector parts and the like, which are exterior materials for vehicles.

[Brief description of the drawings]

FIG. 1 shows a shape and a cross section of a mounted aeropart molded product.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 21/00 C08L 21/00 25/00 25/00 35/00 35/00 35/04 35/04 57 / 00 57/00 69/00 69/00 F-term (reference) 4J002 BC00Y BG04U BG09Y BH02Y BN06W BN06X BN12W BN12X BN14W BN14X BN15W BN15X BN16W BN16X BN17W BN17X BP01U CG00Z AC04 BA03 AC04 AC03BA04 AC03AC04 4J100 AB02Q AB03Q AB07Q AB08Q AJ02R AL10R AM02P AM43Q AM43R AM45Q AM47Q AM48Q AM48R CA04 CA05 JA28

Claims (3)

[Claims] 1. A resin composition comprising 100 parts by weight of a rubber-reinforced styrene resin and 1 to 30 parts by weight of a thermoplastic elastomer, wherein the peak height of a loss tangent (tan δ) measured by viscoelasticity is measured. A vehicle exterior material obtained by molding a resin composition having a peak temperature of −40 to 50 ° C. at a temperature of 0.015 or more. 2. The rubber-reinforced styrene resin is (A) a diene rubber polymer, an acrylic rubber polymer, a silicon rubber polymer or an olefin rubber polymer (Ra) having a volume average particle diameter of 60 to 250 nm. In the presence of 15 to 90 parts by weight, 10 to 90% by weight of an aromatic vinyl compound, 10 to 9% of a (meth) acrylate monomer or a vinyl cyanide monomer.
Monomer mixture consisting of 0% by weight and 0-30% by weight of a monomer copolymerizable therewith (total 100% by weight)
2 to 40 parts by weight of a graft copolymer obtained by polymerizing 5 parts by weight (100 parts by weight in combination with the rubber polymer); (B) a diene rubber polymer having a volume average particle diameter of 260 to 1000 nm; 10 to 90% by weight of an aromatic vinyl monomer in the presence of 15 to 90 parts by weight of a polymer, silicone rubber polymer or olefin rubber polymer (Rb), (meth)
Acrylic ester monomer or vinyl cyanide monomer 1
0 to 90% by weight and monomers 0 to 3 copolymerizable therewith
Monomer mixture 1 consisting of 0% by weight (total 100% by weight)
0 to 85 parts by weight (100 parts by weight in combination with the rubber polymer)
20 to 68 parts by weight of a graft copolymer obtained by polymerizing
(C) Monomer consisting of 10 to 40% by weight of vinyl cyanide monomer, 5 to 80% by weight of aromatic vinyl or maleimide and 0 to 30% by weight of a monomer copolymerizable therewith (total 100% by weight) 0 to 78 parts by weight of a styrene copolymer having a reduced viscosity (30 ° C., in N, N-dimethylformamide solution) of 0.1 to 1.2 dl / g, which is obtained by polymerizing a polymer mixture. And (D) an aromatic polycarbonate 0 having a weight average molecular weight of 10,000 to 35,000
The vehicle exterior material according to claim 1, wherein the exterior material is a rubber-reinforced styrene-based resin consisting of -45 parts by weight [100 parts by weight in total of (A), (B), (C) and (D)]. 3. The vehicle exterior material according to claim 2, wherein the rubber polymer (Rb) of the graft copolymer (B) is a rubber polymer enlarged using an acid group-containing copolymer latex.