JP2002327109A - Polycarbonate-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polycarbonate-based resin composition providing a molding to be readily burst. SOLUTION: This polycarbonate-based resin composition is obtained by compounding (A) a polycarbonate resin and (B) a styrene-based resin with (C) a rubber-like compound such as SBR resin, etc., and (D) a filler such as whisker, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polycarbonate resin composition, an easily rupturable molded article obtained therefrom, and a cover panel for an automobile.

[0002]

2. Description of the Related Art An automobile is equipped with an airbag device for protecting an occupant from an impact at the time of a collision. This airbag device is installed at different places depending on the position where the occupant sits, such as for a driver's seat, for a passenger seat, or for a side collision. Among these, an airbag device for a passenger seat is a so-called dashboard. The part where the airbag pops out is closed by a cover panel that has been scratched so that it can easily burst. And
When the airbag device is activated, the airbag inflates and breaks through the cover panel, jumps out, and deploys toward the occupant sitting in the passenger seat.

[0003] At this time, the cover panel is required to be easily ruptured by the pressure caused by the inflation and deployment of the airbag and to be ruptured cleanly. Here, the term "easy rupture" means that the airbag does not prevent the airbag from inflating and deploying, and, for example, does not cause ductile fracture such as bending and whitening. Also, to burst neatly,
This means that rupture fragments that do not injure the occupant are generated, for example, that they do not flank or generate sharp fracture surfaces.

[0004] However, the conventional cover panel is not always satisfactory because there is a possibility that the cover panel may be bent and whitened, the ruptured pieces may be erected, or ruptured pieces having a sharp fractured surface may be generated.

The present invention relates to a polycarbonate resin composition capable of easily and neatly ruptured when ruptured under pressure, to obtain a molded article having easy rupture properties, an easily rupturable molded article obtained therefrom, and a cover panel. The task is to provide

[0006]

SUMMARY OF THE INVENTION The present inventor has proposed a combination of a polycarbonate resin and an ABS resin as a base resin, and a rubbery compound and an inorganic filler as a modifying component to form a cover panel material for an automobile. The present inventors have found that a suitable composition can be obtained, and have completed the present invention.

That is, the present invention provides a polycarbonate resin composition comprising (A) a polycarbonate resin and (B) a styrene resin, and (C) a rubber compound and (D) a filler. I will provide a.

[0008] Further, as another means for solving the above-mentioned problems, the present invention is a molded article obtained from the above-mentioned polycarbonate resin composition, and the falling weight impact strength specified in JIS K7211 is in the range of 800 to 1600N. Provide an easily burstable molded article.

Further, as another means for solving the above-mentioned problems, the present invention provides an automobile cover panel obtained from the above-mentioned polycarbonate resin composition.

[0010] "Easily burstable" in the present invention means easy and clean bursting as described above.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The polycarbonate resin (A) used in the present invention includes those obtained by reacting a dihydric phenol with a carbonate precursor by a well-known solution method or melting method.

Dihydric phenols are 2,2-bis (4-hydroxyphenyl) propane (bisphenol A), bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2 -Screw (4
-Hydroxy-3,5-dimethylphenyl) propane,
2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4-hydroxy-3-
Methylphenyl) propane, bis (4-hydroxyphenyl) sulfide, bis (4-hydroxyphenyl)
One or more selected from sulfones and the like are included. Of these, bis (4-hydroxyphenyl) alkane-based ones are preferred, and bisphenol A is particularly preferred.

The carbonate precursor is at least one selected from diallyl carbonates such as diphenyl carbonate, dialkyl carbonates such as dimethyl carbonate and diethyl carbonate, carbonyl halides such as phosgene, and haloformates such as dihaloformate of dihydric phenol.

The number average molecular weight of the polycarbonate resin is not particularly limited, but is preferably in the range of about 17000 to 32000 in order to impart a practically required mechanical strength to a molded article obtained from the composition. preferable.

The styrene resin (B) used in the present invention comprises:
It is composed of a styrene resin containing rubber alone or a mixture of a styrene resin containing rubber and a styrene resin containing no rubber.

The styrene-based resin containing rubber includes a copolymer of a monomer of a conjugated diene compound such as butadiene and isoprene and a styrene derivative such as styrene and α-substituted or nuclear-substituted styrene, as well as acrylonitrile, Copolymers with vinyl compounds such as acrylic acid and methacrylic acid are mentioned, and ABS resins are preferred. The ABS resin may be produced by any polymerization method of bulk polymerization or emulsion polymerization, but is preferably produced by bulk polymerization because it has better fluidity.

The styrene resin containing no rubber is a polymer or copolymer containing no conjugated diene compound as described above, and is preferably an AS resin.

The proportion of the (A) polycarbonate resin and (B) styrene resin is preferably 10 to 90% by weight, more preferably 40 to 80% by weight, and more preferably 5 to 80% by weight.
0 to 70% by weight is more preferable, and the component (B) is 90 to 1% by weight.
0% by weight is preferable, 60 to 20% by weight is more preferable, and 50 to 30% by weight is further preferable.

The rubbery compound (C) used in the present invention includes a polystyrene elastomer, a polyolefin elastomer, a polyester elastomer and a polyurethane elastomer. Among these, polystyrene-based elastomers, polyester-based elastomers, and polyurethane-based elastomers are preferable because of good compatibility with the components (A) and (B), and polystyrene-based elastomers are particularly preferable because they have excellent rupture properties. The polystyrene elastomer used as the component (C) is not included in the component (B).

As the polystyrene elastomer used as the component (C), a styrene-butadiene copolymer (SBS resin), preferably an SBS resin having a styrene content of 70% by weight or more (based on raw materials), an epoxy-modified styrene for enhancing heat resistance -Butadiene copolymer (ESBS resin) or a mixture of SBS resin and ESBS resin is preferred. This ESBS resin can be produced, for example, by using the above-mentioned SBS resin by the method described in JP-A-7-25984, page 2, column 2, lines 31 to 43.

The mixing ratio of the rubber compound (C) is (A)
And 0.5 to 4 based on a total of 100 parts by weight of the component (B).
0 parts by weight is preferable, 1 to 10 parts by weight is more preferable,
2-5 parts by weight are more preferred.

As the filler (D) used in the present invention, fibers, flakes, plates, whiskers, granules, and other shapes generally used as a reinforcing material for thermoplastic resins are used, and among these, fibers are preferable. Whiskers are more preferred.

The material of the filler may be an inorganic substance (glass, carbon,
Silicon-containing compounds (such as silicon carbide), metals and metal salts (eg, alumina, tungsten, titanium, copper, potassium titanate,
Zinc carbonate or the like) or an organic substance (aramid fiber or the like). In addition, the surface of the filler, in order to improve the adhesion between the resin and the filler, so long as the object of the invention is not impaired,
It may be treated with a coupling agent such as a silane compound, an epoxy compound, an acrylic compound, and a titanium trisalt.

The whisker may be either a metal or a nonmetal. Aluminum borates, silicon carbide, silicon nitride, potassium titanate, basic magnesium sulfate, zinc oxide, graphite, magnesia, calcium sulfate, sodium calcium phosphate, magnesium borate , Titanium diboride,
Examples thereof include those made of α-alumina, chrysotile, wollastonite, and the like.

The whisker preferably has a high specific gravity in order to suppress the increase in the volume of the whole composition and enhance the fluidity.
The specific gravity is preferably 2 or more, more preferably 2.5 or more, and even more preferably 2.9 or more.

In the present invention, as other fillers, fine hollow glass beads (for example, brand name Scotterat, 3M)
(Made by the company). When the micro hollow glass beads are added to the composition, the molded article can be imparted with appropriate strength and easy rupture properties, so that it is suitable for cover panels.

The mixing ratio of the filler (D) is 0.5 to 40 with respect to 100 parts by weight of the total of the components (A) and (B).
Parts by weight, preferably 1 to 10 parts by weight, more preferably 2 to 10 parts by weight.
-5 parts by weight is more preferred.

The compounding ratio (weight ratio) (C) / (D) of the rubber compound (C) and the filler (D) is preferably from 0.5 to 3, more preferably from 1 to 2.

The composition of the present invention may contain, if necessary, a flame retardant (a hydrated metal flame retardant such as aluminum hydroxide and magnesium hydroxide, a phosphorus flame retardant (red phosphorus, phosphate ester, etc.), Inorganic flame retardants such as antimony oxide), stabilizers against heat, light or oxygen (antioxidants such as phenolic compounds and phosphorus compounds; benzotriazole compounds,
UV absorbers such as benzophenone compounds and phenyl salicylate compounds; hindered amine stabilizers, heat stabilizers such as tin compounds and epoxy compounds, etc.), plasticizers, slidability improvers such as polydimethylsiloxane, lubricants and mold release agents , An antistatic agent, a coloring agent and the like may be added.

The easily rupturable molded article of the present invention is obtained from the polycarbonate resin composition described above.
The falling weight impact strength specified by IS K7211 is 800 to
1600N, preferably in the range of 1100-1400N.

The automobile cover panel of the present invention is for covering the portion where the passenger airbag accommodated in the dashboard protrudes, and is obtained from the above-mentioned polycarbonate resin composition.

[0032]

The present invention will be described below in more detail with reference to Examples, but the present invention is not limited to these Examples. The details of each component and test method used below are as follows.

(A) Component PC: polycarbonate resin (manufactured by Sumitomo Dow Corning Co., Caliber 200-5) (B) component ABS-1: ABS resin (bulk polymerized product) (Japan A & L Co., Santac AT08) ABS-2 : ABS resin (emulsion polymerized product) (Japan A & L Co., Ltd., Santac 290FF) (C) Component ESBS: Hydrogenated epoxy-modified styrene-butadiene copolymer (Epofriend A, manufactured by Daicel Chemical Industries, Ltd.)
T202) PS / PI: styrene-isoprene block copolymer (manufactured by Kuraray Co., Ltd., Hibler 7125) (D) component Whisker: aluminum borate whisker (Alvolex Y) bismuth oxide (Bi ₂ O ₃ ).

(1) Fluidity The fluidity was evaluated by a melt index, and was measured according to ASTM D1.
238. The measurement was performed at 250 ° C., and the total weight of the weight and the piston was 5 kg.

(2) Heat Deformation Temperature (HDT) For an injection molded piece having a thickness of 1/4 ″ inch, AS
Deflection temperature under load based on TM D648-82 (HD
T) (1.82 MPa) was measured.

(3) Charpy impact strength Measured according to ISO 179 / 1eA.

(4) Drop weight impact strength Maximum load (N), maximum load displacement (mm) Measured according to ASTM D3763. As a test piece, a 10 cm × 10 cm × 2 mm flat plate with a 1 mm deep groove in the center was used.

The state of the test piece after the falling weight test was visually observed. Good indicates that the test piece ruptured easily and neatly, and somewhat good indicates that a part of the rupture piece was slightly erected.

Examples 1 and 2 and Comparative Examples 1 to 4 Each component shown in Table 1 [Components (A) and (B) are% by weight, others are parts by weight based on 100 parts by weight of components (A) and (B). ] And melt-kneaded with a twin-screw extruder to obtain a pellet-shaped resin composition. The extrusion molding temperature was 250 ° C., and the whiskers were fed from a side feeder. Each of the above-described tests was performed on these compositions. Table 1 shows the results.

[0040]

[Table 1]

[0041]

According to the polycarbonate resin composition of the present invention, it is possible to obtain a molded article having a property of easily bursting when subjected to an impact, that is, a property of easily and neatly bursting. In particular, it is suitable as a material for a cover panel that closes an opening of an airbag housed in a dashboard of an automobile.

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Claims (9)

[Claims] 1. A polycarbonate resin composition comprising (A) a polycarbonate resin and (B) a styrene resin, and (C) a rubber compound and (D) a filler. 2. The polycarbonate resin composition according to claim 1, wherein the rubbery compound (C) is a styrene-butadiene copolymer and / or an epoxy-modified styrene-butadiene copolymer. 3. The polycarbonate resin composition according to claim 1, wherein (D) the filler is fibrous. 4. The polycarbonate resin composition according to claim 1, wherein the filler (D) is a whisker. 5. The method according to claim 1, wherein (B) the styrenic resin is an ABS resin produced by bulk polymerization.
The polycarbonate resin composition according to the above. 6. A total of 10 to 90% by weight of (A) polycarbonate and 90 to 10% by weight of (B) styrene resin.
The polycarbonate resin according to any one of claims 1 to 5, wherein (C) 0.5 to 40 parts by weight of a rubber compound and (D) 0.5 to 40 parts by weight of a filler are blended with respect to 0 parts by weight. Composition. 7. The compound according to claim 1, wherein the compounding ratio ((C) / (D)) of (C) the rubber compound and (D) the filler is 0.5 to 3 by weight. 2. The polycarbonate resin composition according to 1. 8. A molded article obtained from the polycarbonate resin composition according to any one of claims 1 to 7, wherein
The falling weight impact strength specified by IS K7211 is 800-
An easily burstable molded product having a range of 1600 N. 9. A cover panel obtained from the polycarbonate resin composition according to claim 1 for closing an airbag outlet housed in a dashboard of an automobile.