JPH0680145B2 - Resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a resin composition, and more specifically, it has excellent mechanical strength, a small linear expansion coefficient, and simultaneous coating with a steel sheet for automobile outer panels (hereinafter, The present invention relates to a resin composition that can be suitably used for molding an automobile outer panel that can be referred to as online painting.

<Prior Art> Conventionally, a steel plate has been used for an outer panel of an automobile, but in recent years,
From the standpoints of weight reduction, rust prevention, and freedom of design, part of the vehicle body is becoming plastic.
Generally, automobile outer panels are required to have excellent mechanical strength, heat resistance, cold resistance, dimensional stability, chemical resistance, and appearance.
And, in part, an alloy of polycarbonate and ABS resin has been put into practical use, but the molded product molded from it cannot be applied online because of insufficient heat resistance.
In addition, there is a problem that a coating line for low temperature baking is required and the dimensional stability against temperature change is not always sufficient.

<Object of the Invention> The object of the present invention is to have excellent mechanical strength and a linear expansion coefficient of 8 ×.
It is to provide a resin composition that is 10 ^-5 cm / cm ° C or less and is suitable for molding a molded article that can be painted online.

<Structure of the Invention> The present invention relates to (A) aromatic polycarbonate 5 to 92% by weight (B) polybutylene terephthalate 5 to 92% by weight (C) methacrylic acid in the presence of a rubber containing a repeating unit derived from butadiene. An elastic copolymer obtained by copolymerizing two or more kinds of monomers selected from the group consisting of an ester, an acrylic ester and an aromatic vinyl compound, per 100 parts by weight of the resin component composed of 3 to 20% by weight, D) One or more fillers selected from the group consisting of talc, diatomaceous earth, mica, calcium carbonate, glass beads, glass flakes, and inorganic fibers with L / D ≦ 10 0.3
~ 40 parts by weight and (E) specific surface area (by BET type low temperature nitrogen adsorption method) 150m ²
A resin composition containing 1 to 15 parts by weight of carbon black having an oil absorption of 500 ml / 100 g or more and an oil absorption of 500 ml / g or more.

Aromatic polycarbonate (A) used in the present invention
Is an average molecular weight of 10,000 or more derived from dihydric phenol
It is 100,000, preferably 15,000 to 60,000 polycarbonate, and is usually produced by a solution method or a melting method of a dihydric phenol and a carbonate precursor. Typical examples of the dihydric phenol include bisphenol A [2,2-bis (4-hydroxyphenyl) propane)] and bis (4-
Hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxy-3)
-Methylphenyl) propane and the like. A preferred dihydric phenol is a bis (4-hydroxyphenyl) alkane compound, especially bisphenol A. The dihydric phenols can be used alone or in combination of two or more. Examples of the carbonate precursor include carbonyl halide, carbonate, haloformate and the like. As a typical example, phosgene,
Diphenyl carbonate, dihaloformates of dihydric phenols and mixtures thereof. In producing the aromatic polycarbonate, an appropriate molecular weight modifier, branching agent, catalyst and the like can be used.

The polybutylene terephthalate (B) in the present invention is
A polymer obtained by condensation reaction of terephthalic acid or its ester-forming derivative with tetramethylene glycol or its ester-forming derivative as a main raw material. Furthermore, 30 mol% or less of terephthalic acid is converted to other aromatic dicarboxylic acids. This is a copolymer in which 30 mol% or less of tetramethylene glycol is replaced with other aliphatic diols or alicyclic diols. Examples of the aromatic dicarboxylic acid used in such a copolymer include isophthalic acid and naphthalenedicarboxylic acid.

Further, examples of the diol include polyethylene-α, ω-diols other than tetramethylene glycol, neopentyl glycol, diethylene glycol and the like. The molecular weight of polybutylene terephthalate used in the present invention is not particularly limited, but the intrinsic viscosity measured at 25 ° C. using O-chlorophenol as a solvent is not limited.
Those of about 0.2 to 2.0 can be preferably used.

The elastic copolymer as the component (C) contains two or more monomers selected from the group consisting of methacrylic acid ester, acrylic acid ester and aromatic vinyl compound in the presence of a rubber containing a repeating unit derived from butadiene. It is obtained by copolymerization. Examples of the rubber containing a repeating unit derived from butadiene include polybutadiene, a butadiene-styrene copolymer, a butadiene-acrylonitrile copolymer, a butadiene-acrylic acid ester copolymer and the like. Examples of the methacrylic acid ester and the acrylic acid ester include methyl methacrylate, ethyl methacrylate, butyl methacrylate, octyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate and the like. Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, alkoxystyrene, halogenated styrene and the like.

These elastic copolymers may be produced by any polymerization method such as bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization, and the copolymerization method may be a single-stage graft or a multi-stage graft. Further, it may be a mixture with a copolymer containing only a graft component produced as a by-product during the production. Further, it may be a mixture of two or more elastic copolymers. These elastic copolymers are commercially available and can be easily obtained. For example, Kane Ace B of Kanegafuchi Chemical Co., Ltd.
Series (for example, B-28, B-56, etc.), Kane Ace PA series (for example, PA-20), Metabrene C from Mitsubishi Rayon Co., Ltd.
-223, and further include KIAHA CHEMICAL CO., LTD. HIA-15, BTA series.

Component (D), talc, silica, diatomaceous earth, mica and calcium carbonate are commonly available inorganic powders. Glass beads and glass flakes are also commercially available, but preferably have a particle size of 50 μm or less. When using an inorganic powder, it is desirable to use a silane coupling agent. Further, examples of the inorganic fibers include glass fibers and whiskers. Glass fibers having L / D ≦ 10 are generally commercially available as glass powder and are easily available. Inorganic fibers with L / D> 10 show anisotropy due to fiber orientation and cannot be used for automobile outer panels. Particularly when the temperature is raised, warpage may occur in the molded product.

The carbon black of component (E) used in the present invention has a specific surface area (by BET type low temperature nitrogen adsorption method) of 150 m ² / g.
The above is the carbon black having an oil absorption of 500 ml / 100 g or more. More preferably, the specific surface area is 500 m ² / g or more,
Oil absorption of 500ml / 100g or more.

Examples of such carbon blacks are commercially available as conductive carbon blacks (for example, Ketchien Black EC manufactured by Lion Akzo Co., Vulcan XC-72 manufactured by Cabot Co., Black Pearl 2000, Denka manufactured by Denki Kagaku Kogyo Co., Ltd.). Black, Degussa Printex L, L-60, etc.) and other hydrocarbons such as naphtha are partially oxidized in the presence of steam and oxygen to produce by-products when producing synthesis gas containing hydrogen and carbon monoxide. Examples of such carbon blacks include carbon blacks obtained by oxidizing the carbon blacks. Although the reason is not clear, the effect of the present invention cannot be obtained with carbon black having a specific surface area of less than 150 m ² / g or an oil absorption of less than 500 ml / 100 g.

The resin composition of the present invention is produced by mixing the above-mentioned five kinds of components. The mixing ratio of the component (A) is 5 to
92% by weight, component (B) 5 to 92% by weight, component (C) 3
To 100 parts by weight of the total resin component consisting of ~ 20% by weight,
0.3-40 parts by weight of component (D) and 1-1 of component (E)
5 parts by weight.

When the content of the component (A) is less than 5% by weight in the above resin composition, mechanical properties and thermal properties (for example, heat distortion temperature) are poor, and when it exceeds 92% by weight, moldability is poor. If the content of component (B) is less than 5% by weight, moldability is poor, and if it exceeds 92% by weight, mechanical properties and thermal properties (for example, heat distortion temperature) are poor. When component (C) is less than 3% by weight, the impact value with Izod notch is low, and when it exceeds 20% by weight, mechanical properties (eg tensile strength, bending strength) and thermal properties (eg heat distortion temperature) are deteriorated. Is large and not practical. Component (D) is 0.3 per 100 parts by weight of resin component
If it is less than 10 parts by weight, the coefficient of linear expansion cannot be reduced to 8 × 10 ^-5 cm / cm / ° C or less, and if it exceeds 40 parts by weight, mechanical properties (particularly impact resistance) are reduced, making it practical Not suitable.

When the amount of the component (E) is less than 1 part by weight, the linear expansion coefficient is 8 × 10 ^−5.
If it cannot be controlled to below cm / cm / ° C, and if it exceeds 15 parts by weight, the mechanical properties are significantly deteriorated. When the mixing ratio of the five components is within the above range, the mechanical properties and the coefficient of linear expansion are satisfactory, and the heat resistance is high enough to withstand online coating. A more preferable mixing ratio is the component (A).
10-65 wt%, (B) component 30-85 wt%, (C) component 5
(D) to 100 parts by weight of resin component consisting of ~ 20% by weight
0.4 to 20 parts by weight of component and 1 to 7 parts by weight of component (E).

The resin composition comprising the components (A), (B), (C), (D) and (E) has sufficient impact strength by itself, but 0.5 to 7 parts by weight of polyolefin is added. By doing so, the impact resistance can be further improved. Preferred polyolefins are low density polyethylene, high density polyethylene, polypropylene, polymethylpentene-1, ethylene-propylene copolymer and the like.

Automotive exterior panels molded from thermoplastic resin have excellent moldability, mechanical properties, solvent resistance, etc., and have a small linear expansion coefficient, and in particular, they require heat resistance above a certain level for online coating. Is. As a method for evaluating the heat resistance, generally, a method in which a flat plate is supported horizontally with one-sided tension and how much the tip of the tension hangs from the horizontal position when held in a high temperature atmosphere is suitable. Although the baking conditions of the paint in the online painting are sufficient depending on the paint to be used, it is sufficient to set the ambient temperature to 150 ° C. and the holding time to 1 hour, the present inventor has established that the length of the tension is 100 mm, the width is 12.5 mm,
The thickness is 3.2mm, and the hanging length of the tip of the blade (hereinafter referred to as the drooping length) is 7mm after holding it in the atmosphere of 150 ℃ for 1 hour.
We devised a test method that would pass if: Of course, the smaller the droop length, the better. If the droop length exceeds 7 mm, it will be deformed during online painting, so it is not suitable.

The resin composition of the present invention can be produced by mixing these five components with a mixer such as a tumbler, a blender, a Nauter mixer, a Banbury mixer, a kneading roll, and an extruder. Further, other resins such as polyphenylene ether, polyether sulfone, polyetherimide, polyethylene, ABS resin, stabilizers, antioxidants, low molecular weight polyethylene waxes or ester waxes may be used as long as the object of the present invention is not impaired. A release agent, an ultraviolet absorber or the like may be added.

<Effects of the Invention> The resin composition of the present invention thus obtained can be applied to various well-known molding methods such as injection molding, extrusion molding, compression molding and rotational molding. Are suitable. The molded product obtained in this way has a low coefficient of linear expansion, has little deformation due to temperature changes when combined with metal parts, can be painted online, and can be effectively used as an automobile outer panel. It is a useful material from an industrial viewpoint.

Hereinafter, the present invention will be specifically described with reference to examples.

<Examples 1 to 5 and Comparative Examples 1 to 5> Aromatic polycarbonate (written as PC in the table) and polybutylene terephthalate (written as PBT in the table) at 120 ° C. 6
After drying for more than an hour, blend in the blending ratio shown in Table 1 using a V-type blender, and extruder (30 mmφ vent type extruder
Cylinder temperature 260 using VSK-30 (Nakatani Corp.)
Pelletization was carried out at 0 ° C. to obtain resin composition pellets. After drying the pellets at 120 ° C for 5 hours or more, use an injection molding machine (Toshiba IS-90B type), cylinder temperature 250 ° C, mold temperature 7
Molded under the condition of 0 ℃, the test piece for physical properties, the plate for measuring the droop length (130
mm × 12.5 mm × 3.2 mm ×) and square plate for measuring linear expansion coefficient (1
50 mm x 150 mm x 3 mm) was molded.

The results obtained by measurement are shown in Table 1.

PC: Teijin Chemicals Panlite L-1250 PBT: Teijin Limited polybutylene terephthalate CH-7000 B-28: Kanegabuchi Chemical Co., Ltd. MBS resin B-56: Same as above C-223: Mitsubishi Rayon Co., Ltd. ) MBS resin Methablene HIA-15: Kureha Chemical Co., Ltd. Acrylate / diene elastomer BTA-IIIN: Kureha Chemical Co., Ltd. MBS resin PE: Mitsui Petrochemical Co., Ltd. Mitsui Nisseki Polyethylene HD2100JP Talc: Nippon Talc Co., Ltd. ) Microace Silica: Tokai Kogyo Co., Ltd. Diatomaceous earth: Showa Kagaku Co., Ltd. Mica: Shiraishi Calcium Co., Ltd. Silkron GF (L / D small): Nittobo Co., Ltd. glass powder, L / D: About 8 GF (L) / D)): Nittobo Co., Ltd.
Approx. 30 Ketjen Black: Lion Akzo (Ketjen Black EC, BET specific surface area 1000 m ² / g, oil absorption 1300 ml / 100 g Denka Black: Denki Kagaku Co., BET specific surface area 97
0m ² / g, oil absorption 930ml / 100g Black Pearl: Cabot Black Pearl 2000, BET
Method specific surface area 1475 m ² / g, oil absorption 900 ml / 100 g or more MA-100: Mitsubishi Kasei, BET method specific area 134 m ² / g, oil absorption 101
The units of ml / 100g measurement items are as follows.

Droop length: [mm] Linear expansion coefficient: [× 10 ^-5 cm / cm / ℃] Imp (1/8 ″, notch, 23 ℃): [Kgf · cm / cm]

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location C08L 69/00 LPR 9363-4J // (C08L 67/02 69:00 51:04)

Claims (1)

[Claims] (A) Aromatic polycarbonate 5 to 92% by weight (B) Polybutylene terephthalate 5 to 92% by weight (C) Methacrylic acid ester, acrylic acid in the presence of a rubber containing a repeating unit derived from butadiene (D) talc per 100 parts by weight of the total of the resin component consisting of 3 to 20% by weight of an elastic copolymer obtained by copolymerizing two or more kinds of monomers selected from the group consisting of ester and aromatic vinyl compound, One or more selected from the group consisting of silica, diatomaceous earth, mica, calcium carbonate, glass beads, glass flakes, and inorganic fibers having L / D ≦ 10 (where L is the average length and D is the average diameter). 0.3-40 parts by weight of filler and (E) specific surface area (by BET low temperature nitrogen adsorption method) of 150 m ²
A resin composition containing 1 to 15 parts by weight of carbon black having an oil absorption of 500 ml / 100 g or more / g / g or more.