JPS6212941B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polycarbonate resin composition, and more particularly to a polycarbonate resin composition that can be used for automobile bumpers and the like and has excellent solvent resistance and low-temperature impact resistance. Polycarbonate resin has a high degree of impact resistance, is self-extinguishing, has higher heat resistance than other resins, and has excellent electrical properties and dimensional stability, so it is widely used as an engineering plastic. . However, this polycarbonate resin also has the drawback of low solvent resistance, and therefore, molded products of large size or complex shape with large residual stress sometimes develop stress cracks when exposed to a solvent atmosphere. Because of this drawback, polycarbonate resins have not been widely used in automotive applications where resistance to gasoline, oil, etc. is required. As a result of repeated research in order to improve these drawbacks, the present inventor has found that polyethylene and butyl rubber, isoprene rubber, ethylene-propylene copolymer (EPM) and/or ethylene-propylene-diene in a specific ratio are added to polycarbonate resin. We have discovered that a resin composition containing a copolymer (EPDM) has excellent resistance to gasoline, oil, etc. However, it was later discovered that this resin composition did not have sufficient impact strength or weld strength at low temperatures.
Furthermore, it was found that mica-like peeling sometimes occurred in the outer layer of the molded product during injection molding, and that the product was not completely satisfactory for use in automobile bumpers and the like. As a result of repeated research aimed at further improving these drawbacks, the present inventor found that
The inventors have discovered that this object can be achieved by adding an acrylic elastic polymer and an internal lubricant to the resin composition, and have thus arrived at the present invention. That is, the present invention uses polycarbonate resin (A)
Per 100 parts by weight, 0.3 to 10 parts by weight of polyethylene (B),
Acrylic elastic polymer (C) 0.3 to 10 parts by weight, butyl rubber, isoprene rubber, EPM (ethylene-
0.3 to 10 parts by weight of at least one polymer (D) selected from the group consisting of A polycarbonate resin composition characterized in that components (B), (C), (D), and (E) are blended in a total amount of 2 to 20 parts by weight. The polycarbonate resin composition of the present invention can be molded into a molded product with a good appearance without peeling, and the molded product has excellent solvent resistance, impact resistance at low temperatures, and weld strength, so it can be used for automobile bumpers, etc. can. The polycarbonate resin (A) used in the present invention is obtained by reacting divalent phenol with a carbonate precursor such as phosgene in the presence of an acid acceptor and a molecular weight regulator, or by reacting divalent phenol with a carbonate precursor such as diphenyl carbonate. It is produced by transesterification reaction with The divalent phenol that can be used here is preferably a bisphenol, with 2,2-bis(4-hydroxyphenyl)propane (hereinafter referred to as bisphenol A) being particularly preferred. Further, part or all of bisphenol A may be replaced with another divalent phenol. Examples of divalent phenols other than bisphenol A include hydroquinone, 4,4'-dihydroxydiphenyl, bis(4-hydroxyphenyl)alkane, bis(4-hydroxyphenyl)cycloalkane, and bis(4-hydroxyphenyl). ) sulfide, bis(4-hydroxyphenyl) sulfone, bis(4-hydroxyphenyl) sulfoxide, bis(4-hydroxyphenyl)ketone, bis(4-
hydroxyphenyl) ether or halogenated bisphenols such as bis(3,5-dibromo-4-hydroxyphenyl)propane. It may be a homopolymer of these dihydric phenols, a copolymer of two or more types, or a blend thereof. Further, a part of the polycarbonate resin may be branched, for example, a polyfunctional aromatic compound may be mixed with divalent phenol and/or
It also includes thermoplastic randomly branched polycarbonates reacted with carbonate precursors. Three types of polyethylene with different densities are commercially available, and polyethylenes with medium density and high density are preferably used for the component (B) of the present invention. The acrylic elastic polymer (C) used in the present invention is a copolymer containing methacrylic acid ester or acrylic acid ester as a main component and copolymerized with copolymerized monomers such as styrene, butadiene, acrylonitrile, etc. Esters (e.g. 2-ethylhexyl acrylate, n-
Butyl acrylate, etc.)), 5 to 20 parts by weight, butadiene, 5 to 20 parts by weight, methyl methacrylate, 0 to 10 parts by weight, and a crosslinking agent (e.g., ethylene dimethacrylate, etc.) 0.6 to 1.3 parts by weight. to increase the average particle size to 0.13
5 to 15 parts of styrene as the first graft component to 65 parts by weight of latex rubber adjusted to ~0.20μ
20 to 25 parts by weight of a mixed monomer consisting of 5 to 10 parts by weight of methyl methacrylate, 0 to 10 parts by weight of acrylonitrile, and 0.1 to 0.3 parts by weight of a crosslinking agent (e.g., ethylene dimethacrylate, divinylbenzene, etc.)
parts by weight are graft-polymerized, and further 10-15 parts by weight of a mixed monomer consisting of 10-15 parts by weight of methyl methacrylate and 0.1-0.3 parts by weight of a crosslinking agent (for example, ethylene dimethacrylate, divinylbenzene, etc.) are graft-polymerized as a second graft component. Examples include graft copolymers produced by A specific example of such an acrylic elastic polymer is the product name HIA- from Kureha Chemical Industry Co., Ltd.
An example is one commercially available as No. 15. Furthermore, as the butyl rubber (D ₁ ) of the component (D) used in the present invention, for example, isobutylene and
Synthetic rubber with a low degree of unsaturation obtained by copolymerizing ~7% by weight of isoprene in the presence of a Friedel-Crafts type metal halide such as aluminum chloride at a low temperature, for example, about -100°C, can be mentioned. . Also, as isoprene rubber (D ₂ ), for example, high-purity isoprene is processed using a Ziegler catalyst.
Examples include synthetic rubbers obtained by polymerization in the presence of lithium-based catalysts or SNAM catalysts. Furthermore, as EPM (D ₃ ), for example, ethylene and propylene are mixed in the presence of a Ziegler-Natsuta type improved catalyst at an ethylene/propylene weight ratio of 70/
Synthetic rubbers obtained by copolymerizing in a ratio of 30 to 40/60 can be mentioned. Furthermore, EPDM
Examples of (D ₄ ) include synthetic rubbers obtained by copolymerizing ethylene, propylene, and a diene compound such as hexadiene, dixylopentadiene, or ethylidene norbornene as a third component. These components (D) are easily available as commercial products, but those with high melt viscosity are more preferred. The butyl rubber, isoprene rubber, EPM, and EPDM used in the present invention as component (D) are all
Any commercially available products may be used, but among these, those with a high melt viscosity are preferred. The lubricant of component (E) used in the present invention is a hydrocarbon lubricant such as liquid paraffin, natural paraffin, microwax, polyethylene wax, butyl stearate, stearyl stearate, ethylene glycol monostearate, ethylene glycol monostearate, etc. Preferred are those used as lubricants for polycarbonate resins, such as ester lubricants such as montanate, glycerin monostearate, glycerin tristearate, and the like. In the present invention, these compounding ratios are as follows: 100 parts by weight of polycarbonate resin (A), polyethylene (B), acrylic elastic polymer (C), and a small amount selected from butyl rubber, isoprene rubber, EPM, and EPDM. Each type of polymer (D) is
The amount of lubricant (E) is 0.3 to 10 parts by weight, more preferably 1 to 5 parts by weight, and 0.1 to 1 part by weight. Further, the total amount of (B), (C), (D) and (E) is 2 to 20 parts by weight. Even if the amounts of components (B), (C), (D), and (E) added are smaller or larger than the above ranges, the impact resistance, strength, and appearance of the composition of the present invention cannot be obtained. do not have. The polycarbonate resin composition of the present invention can be prepared by any method, for example, by adding polyethylene to the polycarbonate resin (A).
(B), an acrylic elastic polymer (C), at least one polymer (D) selected from butyl rubber, isoprene rubber, EPM, and EPDM, and a lubricant (E) are added, and V
A method of mixing using a mold blender, super mixer, etc., a method of mixing in a molten state using an extruder, co-kneader, etc.; (B), (C), (D) and (E) components, or (B), There is a method of mixing components (C) and (D) or components (B) and (D) in advance using a kneading roll or Banbury mixer, and then mixing this with unmixed components into the polycarbonate resin directly or in a molten state. . In particular, a multi-stage extrusion method is preferred because it improves the degree of kneading. The composition of the present invention contains additives for the purpose of modifying the polycarbonate resin, such as reinforcing agents such as glass fibers, heat stabilizers, antioxidants, foaming agents, light stabilizers, flame retardants, plasticizers, and mold release agents. agents, antistatic agents, fillers, etc. can be added. Further, other resins such as polystyrene, polymethyl methacrylate, AS resin, ABS resin, polyester, and polyphenylene oxide may be mixed. The present invention will be explained below using examples. In addition, parts in the examples mean parts by weight. Further, evaluation was performed in the following manner. 1. Method for evaluating impact resistance at low temperatures: Pre-dried pellets were molded into test pieces of 64 mm x 12.7 mm x 3.18 mm using an injection molding machine. The test piece was notched with a radius of 0.25 mm and then left in a thermostat at -10°C or -20°C for 1 hour. After being left standing, it was taken out from the thermostat and the impact strength was immediately measured using an Izotsu impact tester (manufactured by Toyo Seiki Co., Ltd.). The higher the impact strength, the better the impact resistance at low temperatures. 2 Weld strength evaluation method: Pre-dried pellets are molded using an injection molding machine equipped with a mold with gates at both ends so that a weld line is formed in the center of the test piece.
Molded into a JIS-K63011 dumbbell. This dumbbell was treated at 23℃ and 50% humidity for 24 hours.
Tensile testing machine (manufactured by Shinko Co., Ltd., TOM500D type)
The tensile strength was measured at 23°C to evaluate the weld strength. The higher the tensile strength, the higher the weld strength. 3. Peelability evaluation method: Pre-dried pellets were molded using a Sumitomo Nestal injection molding machine (Neomatsu 150/75) at a cylinder temperature of 270°C, a mold temperature of 80°C, and an injection pressure.
It was molded into a test piece of 127 mm x 12.7 mm x 3.18 mm under the conditions of 1100 Kg/cm ² , injection time 15 seconds, and cooling time 20 seconds. The peelability of the test piece was evaluated by visually examining whether mica-like layer exfoliation occurred on the surface of the test piece. Examples 1 to 8 and Comparative Examples 1 to 3 To 100 parts of pre-dried polycarbonate resin (A) (manufactured by Teijin Kasei Ltd., Panlite L-1225), polyethylene (B) (manufactured by Mitsui Petrochemical Co., Ltd., 7000F), acrylic elastic polymer (C) (Kureha Chemical Industry Co., Ltd., HIA-15), polymer component (D) and lubricant (E) in the amounts shown in Table 1, and mixed using a super mixer. Then, it was extruded into pellets using a 30 m/m vented extruder (VSK-30, manufactured by Chuo Kikai Co., Ltd.). The pellets were injection molded by the method described above and evaluated for low-temperature impact resistance, weld strength and delamination properties. The results are shown in Table 1.

[Table] From Table 1, it can be seen that the composition of the present invention can be molded into a molded article without peeling and has excellent impact resistance and weld strength at low temperatures.

Claims (1)

[Claims] 1 Per 100 parts by weight of polycarbonate resin (A), 0.3 to 10 parts by weight of polyethylene (B), 0.3 to 10 parts by weight of acrylic elastic polymer (C), butyl rubber, isoprene rubber, ethylene-propylene copolymer, and ethylene-propylene - 0.3 to 10 parts by weight of at least one kind of polymer (D) selected from the group consisting of diene copolymers and 0.1 to 1 part by weight of a lubricant (E) to the above (B), (C),
A polycarbonate resin composition comprising components (D) and (E) in a total amount of 2 to 20 parts by weight.