JPS6311378B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to polycarbonate resin compositions. Specifically, the present invention relates to a polycarbonate resin composition whose impact resistance is less dependent on thickness. Polycarbonate resin is expected to be in great demand as an engineering plastic due to its excellent physical properties, but impact resistance among mechanical properties is highly dependent on thickness, and the The impact fracture strength of is sufficiently high, but the drawback is that the impact fracture strength per cross-sectional area of thick molded products is much smaller than that of thin molded products.If this point could be improved, , it can be expected to have even wider applications. The present inventors have conducted intensive research to obtain a polycarbonate resin whose impact resistance is not dependent on thickness, and have found that when melt-mixing a specific amount of a specific resin,
The present invention was completed based on the knowledge that polycarbonate's inherent impact resistance can be improved, thickness dependence can also be eliminated, and the excellent properties of polycarbonate are not impaired. . That is, the purpose of the present invention is to provide a polycarbonate whose impact resistance is less dependent on thickness, and its gist is to add ethylene and a carbon number of 3 or more to 100 parts by weight of a polycarbonate resin. 0.5 to 40 parts by weight of a modified ethylene copolymer obtained by graft polymerizing 0.05 to 1.5% by weight of α,β-unsaturated carboxylic acid or its anhydride to a copolymer with α-olefin. This is a polycarbonate resin composition obtained by melt-mixing. The present invention will be explained in detail below. The polycarbonate resin used in the present invention has the general formula (In the formula, X is

【formula】

[Formula] represents a divalent group represented by -O-, -S-, -SO- or -SO ₂ -, and the aromatic nucleus may have an alkyl group or a halogen atom. ) is a resin having a repeating unit represented by the general formula (In the formula, X is the same as in the above general formula []. The aromatic nucleus may have an alkyl group or a halogen atom.) Specific examples of the dihydroxydiaryl compound represented by the above general formula [] include bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, and 2,2-bis(4-hydroxy). phenyl)propane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)octane, bis(4-hydroxyphenyl)phenylmethane, 2,2-bis(4) -Hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-tert-butylphenyl)propane, 2,2-bis(4-hydroxy-3-bromophenyl)propane, 2,2-bis(4) -hydroxy-3,5-dibromophenyl)propane, bis(hydroxyaryl)alkanes such as 2,2-bis(4-hydroxy-3,5-dichlorophenyl)propane, 1,1-bis(4 -hydroxyphenyl)cyclopentane, bis(hydroxyaryl)cycloalkanes such as 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxy- Dihydroxyaryl ethers such as 3,3'-dimethyldiphenyl ether, 4,4'-dihydroxyphenyl sulfide, dihydroxy such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide Diaryl sulfides, 4,4'-dihydroxydiphenyl sulfoxide, dihydroxydiaryl sulfoxides such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfone, 4,
Examples include dihydroxydiarylsulfones such as 4'-dihydroxy-3,3'-dimethyldiphenylsulfone. Among these polycarbonate resins, 2,
Polycarbonate resins made from 2'-bis(4-hydroxyphenyl)propane (so-called bisphenol A) are preferred. Examples of methods for producing polycarbonate resins include a phosgene method in which bisphenol A and phosgene are reacted, and a transesterification method in which bisphenol A is reacted with a carbonate ester such as diphenyl carbonate. The modified ethylene copolymer to be melt-mixed with the polycarbonate in the present invention is a copolymer of ethylene and an α-olefin having 3 or more carbon atoms (hereinafter referred to as unmodified ethylene copolymer).
It is obtained by graft polymerizing 0.05 to 1.5% by weight of unsaturated carboxylic acid or its anhydride to unmodified ethylene copolymer. The unmodified ethylene copolymer that is the raw material for the above-mentioned modified ethylene copolymer is prepared by using, for example, a vanadium compound such as vanadium oxytrichloride or vanadium tetrachloride among Ziegler-Natsuta catalysts and an organoaluminium compound, and 50% by mole of ethylene. that's all,
Preferably, 80 to 95 mol% is copolymerized with α-olefin having 3 or more carbon atoms in an amount of 50 mol% or less, preferably 20 to 5 mol%. Examples of α-olefins having 3 or more carbon atoms include propylene, 1-butene, 1-hexene, and 1-decene.
Examples include 1,4-methylbutene-1,4-methylpentene-1, but propylene or butene-1 is preferred. Suitable unmodified ethylene copolymers include a series of resins commercially available under the Tafmer trademark from Mitsui Petrochemical Industries, Ltd., such as Tafmer A series (Tafmer A series such as Tafmer A4085, A4090, A20090, etc.). ethylene-butene-1 copolymer),
Examples include Tafmer P series (ethylene-propylene copolymers) such as Tafmer P0280, P0480, P0680, and P0880. The α,β-unsaturated carboxylic acid or its anhydride (hereinafter simply referred to as unsaturated carboxylic acid) to be graft-polymerized to the unmodified ethylene copolymer is as follows:
Examples include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, and anhydrides of these acids. Among these, maleic anhydride is particularly preferred. The amount of unsaturated carboxylic acid graft-polymerized to the unmodified ethylene copolymer is 0.05 to 1.5% by weight based on the unmodified ethylene copolymer. If this amount is too small, the effect of improving the impact resistance of polycarbonate will be small, and only molded products with low tensile elongation will be obtained, and surface peeling of molded products will occur due to poor compatibility with polycarbonate. So I don't like it. On the other hand, if the amount is too large, it may cause coloring when added to polycarbonate, which is not preferable. Preferably it is in the range of 0.1 to 1% by weight. Graft polymerization is carried out by adding an unsaturated carboxylic acid to an unmodified ethylene copolymer according to a conventional method.
This is done by melting and kneading at 300℃. During this graft polymerization, in order to cause the polymerization to occur efficiently,
Organic peroxide such as α,α′-bis-t-butylperoxy-p-diisopropylbenzene is added in an amount of 0.001 to 0.05% by weight based on the unmodified ethylene copolymer.
It may be used to some extent. The modified ethylene copolymer used in the present invention has a crystallinity (Journal of Polymer Science,
(1955), pages 17 to 26) is 75% or less, preferably 1 to 35%, and the melt index (measured at 190°C according to ASTM D1238 57T) is preferably 75% or less, preferably 1 to 35%. measurement) is
It is preferably from 0.01 to 50, preferably from 0.1 to 20. In order to prepare a modified ethylene copolymer having such a crystallinity and melt index, an unmodified ethylene copolymer having a crystallinity and melt index within the above ranges may be used. In the present invention, a polycarbonate resin composition is prepared by melt-mixing a polycarbonate resin and the above-mentioned modified ethylene copolymer. Melt mixing can be carried out according to conventional methods,
For example, using a device such as a single-screw or multi-screw extruder or a double-screw mixer, the temperature is about 240 to 330°C, preferably 250 to 310°C, for 0.5 to 15 minutes, preferably 1 to 10 minutes. It is best to do this for about a minute. The amount of the modified ethylene copolymer used is 0.5 to 40 parts by weight, preferably 1 to 30 parts by weight, per 100 parts by weight of the polycarbonate resin. If the amount of the modified ethylene copolymer is too small, the effects of the present invention cannot be expected. On the other hand, if the amount is too large, surface peeling of the molded product will occur and the tensile elongation rate will drop significantly, which is not preferable. The polycarbonate resin composition of the present invention can be molded into molded articles of various shapes by various well-known molding methods, such as injection molding, extrusion molding, compression molding, and foam molding. The polycarbonate resin composition of the present invention also contains fibrous reinforcing agents such as glass fibers, carbon fibers, and metal fibers, fillers such as silica, alumina, silica alumina, clays, glass beads, and carbon black, and aromatic Well-known additives such as flame retardants such as Group halogen compounds, stabilizers such as phosphite esters and phosphate esters, other lubricants, ultraviolet absorbers, and colorants may be added, and these can be added using conventional methods. Therefore, it can be added at any stage. The polycarbonate resin composition of the present invention has low thickness dependence of impact resistance and maintains the excellent physical properties originally possessed by polycarbonate resins, so it has great value as an engineering plastic. EXAMPLES The present invention will be specifically explained below 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 "%" indicate "parts by weight" and "% by weight," respectively, and impact resistance (Izot impact strength) is in accordance with ASTM D 256, tensile strength and tensile elongation are in accordance with ASTM D 638, Bending strength and bending modulus are values measured according to ASTM D 790. Production example of modified ethylene copolymer 100 parts of ethylene-butene-1 copolymer with a crystallinity of 20% and a melt index of 3.6 and a butene-1 content of 14 mol%, α dissolved in a small amount of acetone,
α′-bis-t-butylperoxy-p-diisopropylbenzene 0.025 part and maleic anhydride 0.5
This blend was melt-kneaded and extruded at 230° C. using an extruder with a content of 40 mm and L/D=28, and then pelletized to obtain a modified ethylene copolymer. After crushing a portion of this pellet, unreacted maleic anhydride was extracted with acetone, and after press molding, maleic anhydride was quantified by infrared spectroscopy, and it was found that 0.37% of maleic anhydride had undergone graft polymerization. . Examples 1 to 2 and Comparative Examples 1 to 3 100 parts of polycarbonate resin with an average molecular weight of 22,000 (manufactured by Mitsubishi Chemical Industries, Ltd., Novarex 7022A),
The modified ethylene copolymer produced according to the above production example was mixed in the amount shown in Table 1 below, and the inner diameter was 40 mm, L/D
The mixture was melt-mixed and extruded at 280° C. using a No. 28 extruder, and then pelletized to produce polycarbonate resin composition pellets. This pellet is molded using a 3 oz injection molding machine and ASTM
Using a test piece mold, injection molding was performed at a resin temperature of 300°C and a mold temperature of 90°C. The results of measuring the mechanical properties of the obtained test piece were as shown in Table 1 below. For comparison, the results are shown when no modified ethylene copolymer is used, when a large amount of modified ethylene copolymer is used, and when unmodified ethylene copolymer, which is the raw material in the above production example, is used. Also listed.

[Table] Production example of graft copolymer 100 parts of ethylene-butene-1 copolymer with a crystallinity of 20% and a melt index of 3.6 and a butene-1 content of 14 mol%, α dissolved in a small amount of acetone,
α′-bis-t-butylperoxy-p-diisopropylbenzene 0.025 parts, methyl methacrylate
0.15 parts of styrene and 0.35 parts of styrene were blended in a Henschel mixer, and the blend was mixed into a
Melt kneading at 230°C using an extruder with L/D = 28,
A graft copolymer was obtained by extrusion and pelletization. After pulverizing a portion of this pellet, unreacted substances were extracted with acetone, and after press molding, the methyl methacrylate and styrene components were quantified by infrared spectroscopy, and it was found that 0.12% methyl methacrylate and 0.28% styrene were graft polymerized. It has been found. Comparative Example 4 In place of the modified ethylene copolymer in Example 1, 10 parts of the graft copolymer produced according to the above graft copolymer production example was used, and the rest was as in Example 1.
Molding was carried out in the same manner as in . The mechanical properties of the obtained test piece were: Izod impact strength 1/8″60Kg・cm/cm, Izod impact strength 1/2″30Kg・cm/cm,
Tensile strength 490Kg/ ^cm2 , tensile elongation 15%, bending strength 610
Kg/cm ² and flexural modulus of 16,800 Kg/cm ² , the Izod impact strength was low, the thickness dependence was large, and the tensile strength and tensile elongation were also small.

Claims (1)

[Claims] 1 Based on 100 parts by weight of polycarbonate resin, 0.05 to 1.5% by weight of α,β-unsaturated carboxylic acid or its anhydride is grafted to the copolymer of ethylene and α-olefin having 3 or more carbon atoms. Modified ethylene copolymer obtained by polymerization 0.5-40
A polycarbonate resin composition obtained by melt-mixing parts by weight.