JPH0453900B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is a polycarbonate resin mixed with a novel ethylene/aromatic monovinyl copolymer, which has various mechanical properties, particularly excellent impact resistance at low temperatures, and has good properties. The present invention relates to a thermoplastic resin composition that exhibits chemical resistance and good moldability. [Prior Art and its Problems] As is well known, aromatic polycarbonate resins are used as useful engineering plastics because they are tough, have excellent impact resistance, electrical properties, and good dimensional stability. However, there are drawbacks such as high melt viscosity, poor moldability, thickness dependence of impact resistance, and poor chemical resistance, which can cause cracks when in contact with aromatic solvents or gasoline. As a result, the scope of its application is actually limited. For example, in the automobile industry, there is a strong demand for resins that have impact resistance at low temperatures due to safety needs, and for this reason, aromatic polycarbonate resins are attracting attention. However, polycarbonate resin has a high melt viscosity as described above, and is difficult to fill into molds for large molded products such as automobile parts, exhibiting short mold and crepe patterns, making it difficult to obtain good molded products.
Therefore, if the molding temperature is raised to a level that makes filling easier, problems such as thermal decomposition will occur, making it difficult to obtain a molded product with good appearance and stable physical properties. On the other hand, there is a method of improving the moldability by lowering the average molecular weight of the polycarbonate resin, but this method has drawbacks such as a decrease in impact resistance and difficulty in releasing the resin from the mold. In order to improve these drawbacks, proposals have been made to blend various resins into aromatic polycarbonate resins. For example, Japanese Patent Publication No. 40-17663 teaches blending polyolefin, and Japanese Patent Publication No. 40-24191 teaches blending ethylene-propylene copolymer. Although improvement in chemical properties is recognized, the effect of improving impact resistance at low temperatures is small, and there are various defects such as surface peeling phenomenon due to poor compatibility and weakness of weld parts, so it is not always practical. It cannot be said that the improvements are sufficient. [Means for solving the problems] The present invention improves the moldability, chemical resistance, and impact resistance at low temperatures of aromatic polycarbonate resin by blending a new ethylene/aromatic monovinyl copolymer. They have discovered and completed a thermoplastic resin composition that improves the thickness dependence of impact strength and has a well-balanced variety of properties such as mechanical strength and heat resistance. That is, the present invention provides a novel thermoplastic material with excellent chemical resistance and impact resistance containing A. 70 to 99% by weight of aromatic polycarbonate resin and B. 1 to 30% by weight of ethylene/aromatic monovinyl copolymer. It is a resin composition. The present invention will be explained in detail below. A. Aromatic polycarbonate resin of the present invention is:
An optionally branched thermoplastic aromatic polycarbonate polymer made by reacting an aromatic dihydroxy compound or a small amount of a polyhydroxy compound with a diester of phosgene or carbonic acid. An example of an aromatic dihydroxy compound is
2,2-bis(4-hydroxyphenyl)propane (=bisphenol A), tetramethylbisphenol A, tetrabromobisphenol A, bis(4-hydroxyphenyl)-P-diisopropylbenzene, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl and the like, with bisphenol A being particularly preferred. Also,
To obtain a branched aromatic polycarbonate resin, phloroglucin, 4,6-dimethyl-2,
4,6-tri(4-hydroxyphenyl)heptene-2,4,6-dimethyl-2,4,6-tri(4-hydroxyphenyl)heptane, 2,6-
dimethyl-2,4,6-tri(4-hydroxyphenyl)heptene-3,4,6-dimethyl-2,
Examples include 4,6-tri(4-hydroxyphenyl)heptane, 1,3,5-tri(4-hydroxyphenyl)benzene, 1,1,1-tri(4-hydroxyphenyl)ethane, etc. A polyhydroxy compound, and 3,3-bis(4-hydroxyaryl)oxindole (= isatin (bisphenol), 5-chloroisatin, 5,7-dichloroisatin, 5-bromoisatin, etc.) as part of the dihydroxy compound, e.g. 0.1 to 2 mol% is substituted with a polyhydroxy compound.Furthermore,
Monoaromatic hydroxy compounds suitable for controlling the molecular weight include m- and p-methylphenol, m-
- and p-propylphenol, p-bromophenol, p-tert-butylphenol and p-
-Long-chain alkyl-substituted phenols and the like are preferred.
Typical aromatic polycarbonate resins include polycarbonates whose main raw material is bis(4-hydroxyphenyl)alkane compounds, especially bisphenol A. Branched polycarbonate obtained by using a small amount of a trivalent phenol compound in combination can also be mentioned. You may use aromatic polycarbonate resin as a mixture of 2 or more types. B. Ethylene/aromatic monovinyl copolymer used in the present invention has ethylene as its main component, and styrene, α- or β-methylstyrene,
It is formed by copolymerizing an aromatic monovinyl compound having 8 to 10 carbon atoms such as vinyltoluene or isopropenitolene, and the amount of the aromatic monovinyl compound component in the copolymer is preferably 0.1 to 15 mol%. ranges from 1 to 10 mol%. The ethylene copolymer of the present invention has a density of 0.910 to 0.950 g/cm ³ , a melt index (hereinafter abbreviated as MI) of 0.1 to 100 g/min, and is usually free from radicals under high pressure. Manufactured by polymerization method. Here, the radical polymerization method under high pressure refers to a polymerization pressure of 500 to 4000 Kg/cm ² , preferably 1000 to 3500 Kg/cm 2 .
Kg/ ^cm2 , reaction temperature 50~400℃, preferably 100~
free radical catalyst and chain transfer agent under 350°C conditions;
contacting the monomers simultaneously or in stages in a tank or tube reactor, if necessary in the presence of auxiliaries;
A method of polymerization. The free radical catalysts include customary initiators such as peroxides, hydroperoxides, azo compounds, amine oxide compounds, oxygen, and the like. Chain transfer agents include hydrogen, propylene, butene- ₁ , C1- _C20 or higher saturated aliphatic hydrocarbons, and halogen-substituted hydrocarbons, such as methane, ethane, propane, butane, n-
hexane, n-heptane, cycloparaffins,
Chloroform and carbon tetrachloride, saturated aliphatic alcohols of C ₁ to _{C 20} or more, such as sotanol, ethanol, propanol and isopropanol, saturated aliphatic carbonyl compounds of C ₁ to _{C 20} or more, such as carbon dioxide, Included are compounds such as acetone and methyl ethyl ketone and aromatic compounds such as toluene, diethylbenzene and xylene. The blending ratio of the components of the thermoplastic resin composition of the present invention explained above is: A. Aromatic polycarbonate resin 70%
~99% by weight, preferably 80-99% by weight, especially 90
B. Ethylene/aromatic monovinyl copolymer 1 to 30% by weight, preferably 1 to 20% by weight, especially 1 to 10% by weight. The thermoplastic resin composition of the present invention is usually prepared by melt-mixing. If the aromatic polycarbonate resin is less than 70 parts by weight, the heat resistance will not reach the level required for engineering plastics, and the dimensional stability will be poor, and if the new ethylene/aromatic monovinyl copolymer component is less than 1 part by weight, the resistance will be poor. Improvements in chemical properties and impact resistance are not achieved, which is not preferable. The thermoplastic resin composition of the present invention as described above may contain various additives such as stabilizers, pigments, dyes, flame retardants, and lubricants, reinforcing materials such as inorganic or organic fiber materials, and glass. Various fillers such as beads can be blended, and further, other resin components may be blended within a range that does not impair the characteristics of the present invention. For example, polycarbonate from bisphenol A or tetrabromobisphenol A.
Oligomers can be blended to improve moldability, flame retardance, and surface properties, and heat-resistant polyesters such as polyester carbonate and polyarylate (for example, product name: U Polymer, Unitika Co., Ltd.) can be blended to improve heat resistance. Can be mentioned. In preparing the thermoplastic resin composition of the present invention, any conventionally known method may be employed, and a method of kneading with an extruder, Banbury mixer, roll, etc. may be appropriately selected. [Examples] Examples and comparative examples will be described below, and "%", "part" and "molecular weight" are based on weight unless otherwise specified. Examples 1 and 2 and Comparative Examples 1 to 4 Aromatic polycarbonate made from bisphenol A (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name: Iupilon S-2000, molecular weight 25000), ethylene/aromatic monovinyl copolymer (A: Styrene content 14wt%,
MI=1.2g/10min, d=0.936, and B: styrene content 14wt%, MI=2.8g/10min, d=0.936)
were used in the ratios shown in Table 1, and melt-extruded into pellets using a vented extruder (40 mmφ, L/D=25, cylinder temperature 260°C). The pellets were dried in a hot air dryer at 120° C. for 5 hours or more, and then molded into test pieces for measuring physical properties using an injection molding machine and tested for physical properties. The results are shown in Table 1. For comparison, aromatic polycarbonate resin alone (Comparative Example-1), aromatic polycarbonate resin and high-density polyethylene (manufactured by Nippon Petrochemical Co., Ltd., product name:
Staflen E707, MI=0.7g/10min, density 0.950
g/cm ³ ) (Comparative Example-2), LLPE (manufactured by Nippon Petrochemical Co., Ltd., trade name: AF1210, melt index 0.8 g/10 min, density 0.920),
AJ5310, melt index 8.0g/10 minutes, density
0.920) (Comparative Examples-3 and 4), the results were also shown in Table 1 in the same manner as above.

【table】

[Table] (Operations and effects of the invention) As explained above in the detailed explanation, the ethylene/aromatic monovinyl copolymer used in the present invention is:
It is clearly different from that obtained by conventional methods, and it is therefore clear that the composition of the present invention using the copolymer also exhibits excellent properties in terms of fluidity, heat resistance, and impact resistance. be.

Claims (1)

[Claims] 1 A. Aromatic polycarbonate resin 70-99% by weight, B. Ethylene/aromatic monovinyl copolymer 1
A thermoplastic resin composition containing ~30% by weight with excellent chemical resistance and impact resistance.