JPH0550544B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a polycarbonate resin composition. Specifically, the present invention relates to a polycarbonate resin composition that does not cause rust on a mold during hot molding and has excellent thermal stability. [Problems to be solved by the invention] Because polycarbonate resin has a high softening point, it is necessary to heat-form it at high temperatures. In the case of molds made of molded products, inconveniences such as contamination of the molded product surface due to rust often occur. [Means for Solving the Problems] The present inventors have conducted extensive research on methods for preventing mold rust when molding polycarbonate resin, and have found that when blending a specific compound with polycarbonate resin, gold The present invention was completed based on the knowledge that the mold does not rust and the thermal stability of the resin is improved. That is, the present invention aims to provide a polycarbonate resin composition of great industrial value, and its gist is that 100 parts by weight of polycarbonate resin and 0.005 to 0.08 parts by weight of propylene glycol fatty acid ester. It is a polycarbonate resin composition consisting of. The present invention will be explained in detail below. The aromatic polycarbonate resin used in the present invention is a polymer obtained by a phosgene method in which various dihydroxydiaryl compounds are reacted with phosgene, or a transesterification method in which a dihydroxydiaryl compound is reacted with a carbonate ester such as diphenyl carbonate. or a copolymer, typically 2,2-bis(4-
Examples include polycarbonate resins made from hydroxyphenyl)propane (bisphenol A). As the dihydroxydiaryl compound,
In addition to bisphenol A, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 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, 2,2-bis(4-hydroxy-
Bis(hydroxyaryl)alkanes such as 3,5-dichlorophenyl)propane, 1,1-
Bis(hydroxyaryl)cycloalkanes such as bis(4-hydroxyphenyl)cyclopentane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 4,4'-dihydroxydiphenyl ether, 4,4' -dihydroxy-3,
Dihydroxydiaryl ethers such as 3'-dimethyldiphenyl ether, dihydroxydiaryl such as 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide Sulfides, 4,
4'-dihydroxydiphenyl sulfoxide, 4,
Dihydroxydiaryl sulfoxides such as 4'-dihydroxy-3,3'-dimethyldiphenyl sulfoxide, 4,4'-dihydroxydiphenyl sulfone, and 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfone. Examples include dihydroxydiarylsulfones. These may be used alone or in combination of two or more, and in addition to these, hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl, etc. may be used in combination. Examples of fatty acid esters of propylene glycol include esters of propylene glycol and fatty acids, especially fatty acids having 12 to 32 carbon atoms, and specifically, laurate, myristate, palmitate, stearate, oleate, and linoleate of propylene glycol. , ricylate, behenate, montanate, etc., and monoesters of fatty acids having 16 to 18 carbon atoms such as monopalmitate, monostearate, monooleate, monolinoleate, and monorisylate are particularly preferred. The content ratio of fatty acid ester of propylene glycol is based on 100 parts by weight of polycarbonate resin.
The amount is 0.005 to 0.08 parts by weight, preferably 0.01 to 0.08 parts by weight. If the amount is too small, the effects of the present invention cannot be expected. On the other hand, if the amount is too high, silver streaks may appear on the surface of the molded product due to additive analysis, reducing the product value, or gas may be generated during molding, leading to gas vent blockage in the mold and hindering molding. There are inconveniences such as interference. In order to produce the composition of the present invention, the above-mentioned propylene glycol fatty acid ester may be added to the polycarbonate resin at any stage of producing a polycarbonate resin molded article. For example, the above-mentioned propylene glycol may be added to the polycarbonate resin powder or pellets. There are methods such as mixing a glycol fatty acid ester, melt-kneading the above mixture using an extruder or the like and extruding it into pellets, and, in special cases, adding it during the polymerization of polycarbonate. The polycarbonate resin composition thus produced can be processed by various conventionally known methods, such as injection molding,
Any of extrusion molding, compression molding, foam molding, etc. can be employed, but the resin composition of the present invention is particularly suitable for injection molding because it does not cause rust in the mold. The resin composition obtained by the present invention may optionally contain stabilizers, reinforcing agents such as glass fiber, asbestos, and synthetic fibers, silica, silica alumina,
Fillers like alumina, silica and magnesia,
It may contain additives such as flame retardants, dyes and pigments, and lubricants. The polycarbonate resin composition thus obtained does not cause rust on the mold and has excellent thermal stability, so it is very advantageous industrially. [Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. In addition, "parts" in the examples indicate "parts by weight." Examples 1 to 3 and Comparative Examples 1 to 6 100 parts of polycarbonate having an average molecular weight of 21,000 were mixed with propylene glycol monostearate (manufactured by Riken Vitamin Co., Ltd., trademark, Rikemar PS100) in the amount shown in Table 1 below, and a 40 mmφ The mixture was melt-kneaded and extruded into pellets at 280°C using a vented extruder. Using a 3.6-ounce injection molding machine (manufactured by Toshiba Machine Co., Ltd., model IS-75S) and a mold with a disk molding piece, the pellets were heated at a resin temperature of 320°C, a mold temperature of 80°C, and an injection time of 10 seconds.
Molding was performed with cooling for 20 seconds (30 second cycle). In order to test thermal stability, molding was performed with a cooling time of 4 minutes and 50 seconds (5 minute cycle) in the above molding, and the color tone of the molded product in both moldings was compared. As molded products, three molded products with 8th to 10th shots were used, and a colorimetric color difference meter (manufactured by Tokyo Denshoku Co., Ltd., TC) was used.
-55D type) was shown as the average value of three each. In addition, a separate 15 oz injection molding machine (Japan Steel Works, Ltd.)
(N-200A type) and mild steel (S55C), using a Kotsupu mold, resin temperature 300℃, mold temperature 80℃,
Continuous molding of 500 shots was performed with an injection time of 10 seconds and a cooling time of 20 seconds, and the molded product was left to cool while remaining in the mold during final molding. After 24 hours, the molded product was taken out and the state of rust on the mold surface was visually determined. The results were as shown in Table 1 below. For comparison, when propylene glycol monostearate was not used (Comparative Example 1),
When the blending amount was too large (Comparative Examples 2 and 3), instead of propylene glycol monostearate,
When using montanate ester of ethylene glycol (manufactured by Hoechst Co., Ltd., trademark, Hoechstwax E) (Comparative Example 4), glycerin monostearate (manufactured by Riken Vitamin Co., Ltd., trademark, Rikemar S100A)
(Comparative Example 5) and stearyl stearate (manufactured by Riken Vitamin Co., Ltd., trademark, Rikemar)
S900) (Comparative Example 6) is also shown.

〔Effect of the invention〕

The composition of the present invention has the effect that the mold does not rust and the thermal stability of the resin is improved.

Claims (1)

[Scope of Claims] 1. A polycarbonate resin composition comprising 100 parts by weight of polycarbonate resin and 0.005 to 0.08 parts by weight of fatty acid ester of propylene glycol. 2 The fatty acid ester of propylene glycol is
The polycarbonate resin composition according to claim 1, which is an ester of propylene glycol and a fatty acid having 12 to 32 carbon atoms.