Aromatic polycarbonate resin composition

An aromatic polycarbonate resin composition having hydroxyl groups as end groups is thermally stable and also offers excellent resistance to hydrolysis. The polycarbonate resin composition incorporates (A) an aromatic polycarbonate resin containing hydroxyl groups in the proportion of 5% or more of the total end groups and a metal impurity and (B) a deactivating agent selected from the group consisting of phosphorous acid, a thioether compound, a phosphite diester and a nitrogen-containing organic compound. The amount of deactivating agent is based on the amount of metal impurity in (A) and the type of deactivating agent.

CROSS-REFERENCE TO RELATED APPLICATIONS 
Not Applicable. 
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH 
Not Applicable. 
This invention relates to resin compositions of a stabilized, aromatic 
polycarbonate (sometimes referred to below as PC) containing hydroxyl 
groups. 
Conventional methods of manufacturing aromatic polycarbonates are well 
known. For example, the specifications of Japanese Publication of 
Unexamined Patent Application (Kokai) Hei 2-175723, Japanese Publication 
of Unexamined Patent Application (Kokai) Hei 2-124934, U.S. Pat. No. 
4,001,184, U.S. Pat. No. 4,238,569, U.S. Pat. No. 4,238,597 and U.S. Pat. 
No. 4,474,999 describe well-known methods for synthesizing polycarbonates 
by ester interchange or transesterification of a dihydric phenol and 
carbonate diester in the molten state, or methods, particularly, 
interfacial methods, that react phosgene with dihydric phenol in a solvent 
solution. 
Compared to polycarbonates obtained using phosgene methods, the amount of 
residual chlorine in polycarbonates derived from melt polymerization 
methods is extremely small because neither phosgene nor chlorine-based 
solvents are used. However, because melt methods polymerize by utilizing 
ester exchange methods, the endcapping method is often controlled by the 
molar ratio of the raw materials and several percent of hydroxyl groups 
derived from the raw material are present in the composition. In contrast, 
in the phosgene method (interfacial method), hydroxyl groups derived from 
the raw material are present based on the amount of endcapping or 
terminating agents. 
Polycarbonates that have hydroxyl groups as end groups are stable and offer 
no problems whatsoever with respect to heat of short duration such as in 
mold forming, but they do have potential problems in that these hydroxyl 
groups may react with, for example, impuritiesin the polycarbonate and/or 
metals, etc. originating from molding machines during molding that become 
intermixed with the polycarbonate. The higher the processing temperature, 
the greater the possibility of such reactions occurring. Thus, there is a 
possibility that such reactions may lead to problems of unexpected 
discoloration and/or a reduction of molecular weight of the polycarbonate. 
In particular, in recent years, processing temperatures when mold forming 
aromatic polycarbonates for lenses and optical disks have exceeded 
300.degree. C. with the objective of achieving surface smoothness and 
reducing residual strain. In particular, temperatures exceeding 
320.degree. C. have become commonplace in the case of optical disks. 
Further, processing temperatures for extremely thin optical disks are 
approaching 350.degree. C. In such high-temperature molding, the problems 
that demand the greatest attention are discoloration and reduction in 
product strength resulting from a drop in molecular weight, and 
polycarbonate resins with high thermal stability are therefore required to 
prevent such problems. 
In polycarbonates manufactured by the melt-process, the most likely 
impurities to occur in the PC resin are metallic ions. However, because 
the metallic ion content often is derived from the raw materials and also 
from the materials used to fabricate reactors, etc., it is difficult to 
eliminate them entirely. Japanese Publication of Unexamined Patent 
Application (Kokai) Hei 2-175722 establishes that metallic ions and some 
amount of chlorine exist in melt-processed polycarbonates, and improves 
the resistance to hydrolysis by increasing the purity of the 
polycarbonate. Nevertheless, during secondary processing, metals or 
metallic ions can be introduced during mold forming from, for example, 
extruder barrel walls, screws, etc. Consequently, there are limitations to 
this method, and methods that provide greater stabilization are highly 
desirable in order to stabilize melt-processed polycarbonates having 
hydroxyl groups. 
The objective of this invention is to provide an aromatic carbonate resin 
composition having hydroxyl groups as end or terminal groups which is 
thermally stable and has excellent resistance to hydrolysis. 
The result of diligent study of the stabilization of hydroxyl-containing 
polycarbonates by the inventors has led to the concept that it would be 
desirable to predict the interaction of hydroxyl groups with metals in 
advance and deactivate the action of the metals to prevent problems of 
discoloration. Accordingly, the inventors discovered that adding to a 
polycarbonate containing hydroxyl groups and a metal from about 1 to about 
100 moles of phosphorous acid or from about 1 to about 1,000 moles of a 
thioether compound or from about 1 to about 1,000 moles of a phosphite 
diester for each mole of metal or a nitrogen-containing organic compound 
which is a heavy metal deactivating agent in an amount of from about 10 to 
about 500 ppm per part by weight of the aromatic polycarbonate causes the 
aromatic polycarbonate having such hydroxyl groups to become exceptionally 
stable and arrived at this invention. 
This invention provides a polycarbonate resin composition comprising (A) an 
aromatic polycarbonate resin containing hydroxyl groups in the proportion 
of least 5% of total end groups and a metal impurity and (B) an amount of 
a deactivating agent selected from the group consisting of phosphorous 
acid wherein the amount is from about 1 to about 100 moles per mole of 
metal impurity contained in component (A), a thioether compound wherein 
the amount is from about 1 to about 1,000 moles per mole of metal impurity 
contained in component (A), a phosphite diester wherein the amount is from 
about 1 to about 1,000 moles per mole of metal impurity contained in 
component (A) or a nitrogen-containing organic compound which is a heavy 
metal deactivating agent in an amount of from about 10 to about 500 ppm 
per part by weight of the aromatic polycarbonate. 
One embodiment of this invention provides a polycarbonate resin composition 
characterized in that it incorporates (A) an aromatic polycarbonate resin 
containing hydroxyl groups in the proportion of least 5% of total end 
groups and (B) phosphorous acid, and the amount of (B) phosphorous acid 
contained therein is in the proportion of from 1 to 100 moles per mole of 
metal impurity contained in constituent (A). 
A second embodiment of this invention provides a polycarbonate resin 
composition containing (A) an aromatic polycarbonate resin containing 5% 
or more of hydroxyl groups with respect to the total end groups and (B) a 
thioether compound, in which the amount of (B) the thioether compound 
contained therein is 1 to 1,000 moles per mole of metal impurities 
contained in component (A). 
A third embodiment of this invention provides a polycarbonate resin 
composition containing (A) an aromatic polycarbonate resin containing 5% 
or more of hydroxyl groups with respect to the total end groups and (B) a 
phosphite diester, in which the amount of (B) the thioether compound 
contained therein is 1 to 1,000 moles per mole of metal impurities 
contained in component (A). 
A fourth embodiment of this invention provides a polycarbonate resin 
composition containing (A) an aromatic polycarbonate resin containing 5% 
or more of hydroxyl groups with respect to the total end groups and (B) a 
phosphite diester, in which the amount of (B) the thioether compound 
contained therein is a nitrogen-containing organic compound which is a 
heavy metal deactivating agent in an amount of from about 10 to about 500 
ppm per part by weight of the aromatic polycarbonate. 
It is preferable that the aforementioned aromatic polycarbonate resin be 
manufactured by a melt polymerization reaction of a carbonate diester with 
an aromatic dihydroxyl compound. During the melt polymerization, it is 
preferable to use from 1.times.10-8 to 1.times.10-4 mole of an alkali 
metal compound or alkaline earth metal compound, and further, from 
1.times.10-6 to 1.times.10-1 mole of a basic compound per mole of aromatic 
dihydroxyl compound as catalysts in the melt polymerization reaction. 
In most instances, the aforementioned metal impurity is a compound of iron. 
It is preferable to base the level of deactivating agent on the level of 
iron in the aromatic polycarbonate resin. 
In this invention, the aromatic polycarbonate resin containing hydroxyl 
groups in the proportion of at least 5% of total end groups (A) is an 
aromatic homo-polycarbonate or co-polycarbonate obtained by reacting a 
carbonate precursor with an aromatic dihydroxy compound. In addition, the 
aromatic polycarbonate may be branched. Such branched polycarbonates can 
be obtained by reacting a polyfunctional aromatic compound with an 
aromatic dihydroxy compound and a carbonate precursor to make a branched 
thermoplastic branched polycarbonate. 
There are no particular limitations on the molecular weight of the aromatic 
polycarbonate resin (A) component, but from a practical standpoint, it is 
preferable that it have an limiting viscosity [.eta.] of from 0.3 to 0.7 
as measured in ethylene chloride at 20.degree. C. using a Ubbelohde 
viscometer. 
The method of manufacturing polycarbonates described is public knowledge 
per se. Specifically, they can be manufactured by bringing about an ester 
exchange reaction of a carbonate diester with an aromatic dihydroxy 
compound (for example, dihydric phenol) in the melt. Or, they can be 
manufactured by methods (particularly, interfacial methods) that react 
phosgene with an aromatic dihydroxy compound (for example, dihydric 
phenol) in a liquid solution. Polycarbonate fabrication methods are 
described in the specifications of Japanese Publication of Unexamined 
Patent Application (Kokai) Hei 2-175723, Japanese Publication of 
Unexamined Patent Application (Kokai) Hei 2-124934, U.S. Pat. No. 
4,001,184, U.S. Pat. No. 4,238,569, U.S. Pat. No. 4,238,597 and U.S. Pat. 
No. 4, 474,999. 
The melt method is described in detail below. 
There are no particular limitations on the aromatic hydroxyl compound and a 
variety of well known compounds having phenolic hydroxyl groups can be 
used. Such compounds, for example, have the general formula 
##STR1## 
In the above-mentioned formula, Ra and Rb, independent of each other, are 
selected from among a halogen, for example, chlorine, bromine, fluorine, 
iodine and an alkyl group having from 1 to 8 carbons atoms, and, when Ra 
or Rb are plural in number, that is to say, when n=2 to 4 and/or m=2 to 4, 
it is acceptable for either Ra or Rb to be identical or different; n and m 
being an integer between 0 and 4, respectively; and X being selected from 
among a single bond, an alkylene group having from 1 to 8 carbon atoms, an 
alkylidene group having from 2 to 8 carbon atoms, a cycloalkylene group 
having from 5 to 15 carbons, a cycloalkylidene having from 5 to 15 carbon 
atoms, and an --S--, --SO--, --SO2--, --CO--, --O-- bond, and a bond 
represented by the following formula: 
##STR2## 
Preferred aromatic dihydroxy compounds include dihydroxy arylalkanes such 
as 
bis-(4-hydroxyphenyl)-methane, 
1,1-bis-(4-hydroxyphenyl)-ethane, 
1,2-bis-(4-hydroxyphenyl)-ethane, 
bis-(4-hydroxyphenyl)-diphenyl-methane, 
bis-(4-hydroxyphenyl)-diphenyl-methane, 
2,2-bis-(4-hydroxyphenyl)-propane, 
2,2-bis-(4-hydroxyphenyl)-butane, 
1,1-bis-(4-hydroxyphenyl)-cyclohexane, 
bis-(3,5-dimethyl-4-hydroxyphenyl)-methane, 
1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-ethane, 
1,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-ethane, 
2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane, 
2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-butane, 
bis-(3,5-dimethyl-4-hydroxyphenyl)-phenyl-methane, 
bis-(3,5-dimethyl-4-hydroxyphenyl)-diphenyl-methane, 
bis-(3,5-dichloro-4-hydroxyphenyl)-methane, 
2,2-bis-(3,5-dichloro-4-hydroxyphenyl)-methane, 
bis-(3,5-dibromo-4-hydroxyphenyl)-methane, 
2,2-bis-(3,5-dibromo-4-hydroxyphenyl)-propane, etc.; 
dihydroxy arylsulfones such as 
bis-(4-hydroxyphenyl)-sulfone, 
bis-(3,5-dimethyl-4-hydroxyphenyl)-sulfone, 
bis-(3,5-dibromo-4-hydroxyphenyl)-sulfone, etc.; 
dihydroxy arylethers such as 
bis-(4-hydroxyphenyl)-ether, 
bis-(3,5-dimethyl-4-hydroxyphenyl)-ether, 
bis-(3,5-dibromo-4-hydroxyphenyl)-ether, etc.; 
dihydroxy arylsulfides such as 
bis-(4-hydroxyphenyl)-sulfide, 
bis-(3,5-dimethyl-4-hydroxyphenyl)-sulfide, 
bis-(3,5-dibromo-4-hydroxyphenyl)-sulfide, etc.; 
dihydroxy arylketones such as 
4,4'-dihydroxybenzophenone; or 
sulfoxones such as 
bis-(4-hydroxyphenyl)-sulfoxone. 
Among these, 2,2-bis-(4-hydroxyphenyl)-propane (commonly known as bisphenol 
A or BPA) is more preferable. 
In addition to the above-mentioned substances, compounds represented by the 
following general formula 
##STR3## 
here, Rf is a hydrocarbon group having from 1 to 10 carbon atoms or its 
halogenide, or a halogen atom, p being an integer from 0 to 4, for 
example, resorcin as well as substituted resorcins such as 
3-methyl-resorcinol, 
3-ethyl-resorcinol, 
3-propyl-resorcinol, 
3-butyl-resorcinol, 
3-t-butyl-resorcinol, 
3-phenyl-resorcinol, 
3-cumyl-resorcinol, 
2,3,4,6-tetrafluoro-resorcinol, 
2,3,4,6-tetrabromo-resorcinol, etc.; 
catechol; 
hydroquinone as well as substituted hydroquinones such as 
3-methyl-hydroquinone, 
3-ethyl-hydroquinone, 
3-propyl-hydroquinone, 
3-butyl-hydroquinone, 
3-t-butyl-hydroquinone, 
3-phenyl-hydroquinone, 
3-cumyl-hydroquinone, 
2,3,5,6-tetramethyl-hydroquinone, 
2,3,5,6-tetra-t-butyl-hydroquinone, 
2,3,5,6-tetrafluoro-hydroquinone, 
2,3,5,6-tetrabromo-hydroquinone, etc.; 
as well as . . . 
2,2,2',2'-tetrahydro-3,3,3',3'-tetramethyl-1,1'-spirobis-(1H-indene)-7,7'- 
diol, etc., represented by the formula 
##STR4## 
and a substituted indane bisphenol compound as taught in U.S. Pat. No. 
5,703,197, expressly incorporated herein by reference, at column 6, lines 
10 to 24, the most preferred species of which is 
5-hydroxy-3-(4-hydroxyphenyl)-1,1,3-trimethylindane which gives a 
structure as set forth in the formula below 
##STR5## 
when incorporated into the polycarbonate copolymer. can be used as the 
aromatic dihydroxy compound. 
It is acceptable to use these aromatic hydroxy compounds alone, or it is 
acceptable to use two or more compounds in combination. 
There are no particular restrictions on the carbonate diester, and diphenyl 
carbonate, ditolyl carbonate, bis-(chlorophenyl) carbonate, m-cresyl 
carbonate, dibutyl carbonate, bis-(diphenyl) carbonate, diethyl carbonate, 
dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, etc., can 
be cited as examples, but it is not restricted to these. It is preferable 
to use diphenyl carbonate. 
It is also acceptable to use these carbonate esters either alone or in 
combinations of two or more. 
In addition to these, it is also acceptable that it contain a dicarboxylic 
acid or a dicarboxylic ester as acid components. 
Aromatic dicarboxylic acid compounds such as 
terephthalic acid, 
isophthalic acid, 
diphenyl terephthalate, 
diphenyl isophthalate, etc.; 
aliphatic dicarboxylic acid compounds such as 
succinic acid, 
glutaric acid, 
adipic acid, 
pimelic acid, 
suberic acid, 
azelaic acid, 
sebacic acid, 
decanedioic acid, 
dodecanedioic acid, 
diphenyl sebacate, 
diphenyl decanedioate, 
diphenyl dodecanedioate, etc.; and 
alicyclic dicarboxylic acid compounds such as 
cyclopropane-dicarboxylic acid, 
1,2-cyclobutane dicarboxylic acid, 
1,3-cyclobutane dicarboxylic acid, 
1,2-cyclopentane dicarboxylic acid, 
1,3-cyclopentane dicarboxylic acid, 
1,2-cyclohexene dicarboxylic acid, 
1,3-cyclohexene dicarboxylic acid, 
1,4-cyclohexene dicarboxylic acid, 
diphenyl cyclopropanedicarboxylate, 
diphenyl 1,2-cyclobutanedicarboxylate, 
diphenyl 1,3-cyclobutanedicarboxylate, 
diphenyl 1,2-cyclopentanedicarboxylate, 
diphenyl 1,3-cyclopentanedicarboxylate, 
diphenyl 1,2-cyclohexenedicarboxylate, 
diphenyl 1,3-cyclohexenedicarboxylate, 
diphenyl 1,4-cyclohexenedicarboxylate, etc., 
can be cited as examples of dicarboxylic acids or dicarboxylic esters. 
It is also acceptable to use these dicarboxylic acids or dicarboxylic 
esters either alone or in combinations of two or more. 
It is preferable that the amount of dicarboxylic acid or dicarboxylic ester 
contained in the above-mentioned carbonate diester be less than 50 mole 
percent, and even more preferable that it be less than 30 mole percent. 
When manufacturing an aromatic polycarbonate, a polyfunctional compound 
having at least three functional groups in the molecule can be used 
together with an aromatic dihydroxyl compound and a carbonate diester. It 
is preferable that these polyfunctional compounds be a compound having a 
phenolic hydroxyl group or a carboxyl. In particular, compounds containing 
three phenolic hydroxyl groups are more preferred. As specific examples of 
these preferred compounds, 
1,1,1-tris-(4-hydroxyphenyl)-ethane, 
2,2',2"-tris-(4-hydroxyphenyl)-di-isopropylbenzene, 
.alpha.-methyl-.alpha.,.alpha.',.alpha."-tris-(4-hydroxyphenyl)-1,4-diethyl 
benzene, 
.alpha.,.alpha.',.alpha."-tris-(4-hydroxyphenyl)-1,3,5-tri-isopropylbenzene 
flouroglycine, 
4,6-methyl-2,4,6-tri-(4-hydroxyphenyl)-heptane-2, 
1,3,5-tri-(4-hydroxyphenyl)-benzene, 
2,2-bis-(4,4'(4,4'-hydroxyphenyl)cyclohexyl)-propane, 
trimellitic acid, 
1,3,5-benzene-tricarboxylic acid, 
pyromellitic acid, etc., can be cited. 
Further, it is even more preferable that 
1,1,1-tris-(4-hydroxyphenyl)-ethane, 
.alpha.,.alpha.',.alpha."-tris-(4-hydroxyphenyl)-1,3,5-tri-isopropylbenzen 
e, etc., be used. 
It is preferable that the amount of polyfunctional compound used be less 
than 0.03 mole per mole of aromatic dihydroxyl compound, more preferable 
that it be from 0.002 to 0.02 mole, and especially preferable that it be 
from 0.01 to 0.02 mole. 
The amount of terminal hydroxyl groups in the aromatic polycarbonate 
depends on the molar ratio of the raw materials, i.e., the aromatic 
dihydroxyl compounds and the diester carbonates. For example, when using 
bisphenol A as the aromatic dihydroxyl compound and diphenyl carbonate as 
the carbonate diester, the end groups of the polycarbonate will be (I) 
phenolic residual groups derived from bisphenol A and (II) phenyl groups 
derived from the diphenyl carbonate. If the molar ratio of bisphenol A is 
increased, the equivalence ratio of (I)/(II) of the phenolic terminal 
groups (I) and non-phenolic terminal groups (II) in the polycarbonate so 
formed will increase. 
When using the melt method of manufacturing polycarbonates, the molar ratio 
of bisphenol A (an aromatic dihydroxy compound) is generally large, and 
the amount of phenolic end groups in the aromatic polycarbonate so 
obtained will be at least 5% of the total end groups. 
In addition, when manufacturing polycarbonates using the melt method in 
such a manner, an alkali metal compound or alkaline earth metal compound 
and a basic compound are normally used as a catalyst. Specifically, 
organic salts, inorganic salts, oxides, hydroxides, hydrides or alcholates 
of alkali metal compounds or alkaline earth metal compounds can be cited 
as being preferable as the alkali metal compound or alkaline earth metal 
compound. 
Specifically, sodium hydroxide, potassium hydroxide, lithium hydroxide, 
sodium hydrogencarbonate, potassium hydrogencarbonate, lithium 
hydrogencarbonate, sodium carbonate, potassium carbonate, lithium 
carbonate, sodium acetate, potassium acetate, lithium acetate, sodium 
stearate, potassium stearate, lithium stearate, sodium bromohydride, 
lithium bromohydride, phenylbromo-sodium, sodium benzoate, potassium 
benzoate, lithium benzoate, disodium hydrogenphospate, dipotassium 
hydrogenphosphate, dilithium hydrogenphospate, the sodium salt of 
bisphenol A, dipotassium salts, dilithium salts, the sodium salts of 
phenols, potassium salts, lithium salts, etc., can be cited as alkali 
metal compounds. 
Specifically, calcium hydroxide, barium hydroxide, magnesium hydroxide, 
strontium hydroxide, calcium hydrogencarbonate, barium hydrogencarbonate, 
magnesium hydrogencarbonate, strontium hydrogencarbonate, calcium 
carbonate, barium carbonate, magnesium carbonate, strontium carbonate, 
calcium acetate, barium acetate, magnesium acetate, strontium acetate, 
calcium stearate, barium stearate, magnesium stearate, strontium stearate, 
etc., can be cited as alkaline earth metal compounds. 
The alkali metal compounds or the alkaline earth metal compounds mentioned 
above can also be used in combinations of two or more. In addition, alkali 
metal compounds and alkaline earth metal compounds can be used in 
combination. 
For alkali metal compounds or the alkaline earth metal compounds such as 
these, it is preferable to use from 1.times.10-8 to 1.times.10-4 mole per 
mole of the above-mentioned aromatic dihydroxyl compound, more preferable 
from 1.times.10-7 to 2.times.10-6 mole, and is especially preferable to 
use from 1.times.10-7 to 8.times.10-7 mole. 
As catalysts, if alkali metal compounds or the alkaline earth metal 
compounds are used in the amount of from 1.times.10-8 to 1.times.10-4 mole 
per mole of aromatic dihydroxyl compound, polymers with high 
polymerization activity can be manufactured. 
In addition, basic compounds are used together with the alkali metal 
compounds or the alkaline earth metal compounds. It is desirable that 
these basic compounds exhibit, for example, ready decomposition at high 
temperatures. The following compounds can be specifically cited; to wit, 
ammonium hydroxide compounds that have alkyl, aryl, aralkyl, etc., groups 
such as tetramethyl ammonium hydroxide (Me.sub.4 NOH), tetraethyl ammonium 
hydroxide (Et.sub.4 NOH), tetra butyl ammonium hydroxide (Bu.sub.4 NOH), 
trimethylbenzyl ammonium hydroxide ((.phi.-CH.sub.2)(Me).sub.3 NOH), 
tertiary amines such as trimethylamine, triethylamine, dimethylbenzylamine, 
triphenylamine, etc., 
secondary amines represented by R.sub.2 NH (in the formula, R is an aryl 
group, etc., of an alkyl, phenol, tolyl, etc., such as methyl, ethyl, 
etc.), 
primary amines represented by RNH.sub.2 (in the formula, R is synonymous to 
that described above), 
imidazoles such as 2-methylimidazole, 2-phenylimidazole, etc., 
basic salts such as ammonia, tetramethyl ammonium borohydride (Me.sub.4 
NBH.sub.4), tetrabutyl ammonium borohydride (Bu.sub.4 NBH.sub.4), 
tetrabutyl ammonium tetraphenyl borate (Bu.sub.4 NB(Ph).sub.4), 
tetramethyl ammonium tetraphenyl borate (Me.sub.4 NB(Ph).sub.4), etc., 
and, 
phosphonium compounds such as tetramethyl phosphonium hydroxide, tetraethyl 
phosphonium hydroxide, tetraphenyl phosphonium hydroxide, etc. 
Among these, it is preferable to use tetraalkyl ammonium hydroxide 
compounds, particularly, tetraalkyl ammonium hydroxide compounds for 
electronic use that contain few metallic impurities. 
As for the basic compounds such as those described above, it is preferably 
to use from 1.times.10-6 to 1.times.10-1 mole for each mole of aromatic 
dihydroxyl compound, and more preferable to use from 1.times.10-5 to 
1.times.10-2 mole. 
If both alkali metal compounds or alkaline earth metal compounds and basic 
compounds are used in combination in the amounts described above, the 
polycondensation reaction can proceed with sufficient speed and is 
preferable to be able to form high-molecular-weight polymers with high 
polymerization activity. 
When using catalysts such as those described above in the melt 
polymerization method, it is preferable to neutralize or weaken the 
reaction product by adding acidic compounds. Sulfonic acids such as 
benzenesulfonic acid, p-toluenesulfonic acid, etc., sulfonic acid esters 
such as methyl benzenesulfonate, ethyl benzenesulfonate, butyl 
benzenesulfonate, octyl benzenesulfonate, phenyl benzenesulfonate, methyl 
p-toluenesulfonate, ethyl p-toluenesulfonate, butyl p-toluenesulfonate, 
octyl p-toluenesulfonate, phenyl p-toluenesulfonate, etc., can be used as 
such acidic substances. 
In the melt method, as the purification involved in the phosgene method is 
essentially not carried out, it is preferable to process the polymer at 
reduced pressure after neutralizing the catalyst. 
There are no particular limitations on the processing equipment when doing 
such reduced pressure processing, but it is also acceptable to use 
reactors equipped with a depressurization system, or to use an extruder 
equipped with a depressurization system. 
When using such reaction vessels, it is acceptable use either a vertical or 
horizontal tank-type reactor, but it is preferable to use a horizontal 
tank-type reactor. 
Reduced-pressure processing conducted using reactors like those described 
above is carried out at pressures from 0.05 to 750 mm Hg, and preferably 
at pressures below 0.05 to 5 mm Hg. 
When using an extruder, it is preferable to carry out such reduced-pressure 
processing for about 10 seconds to 15 minutes, and when using a reactor, 
it is preferable to process for about 5 minutes to 3 hours. In addition, 
it is preferable to carry out reduced-pressure processing at a temperature 
of about 240.degree. to 350.degree. C. 
In addition, when reduced-pressure processing is carried out in an 
extruder, it is acceptable to use either a vented uniaxial extruder or a 
biaxial extruder, and pelletization can also be carried out while doing 
reduced-pressure processing in an extruder. 
When reduced-pressure processing is done in an extruder, the 
reduced-pressure processing is done at a pressure of about 1 to 750 mm Hg, 
and preferably under conditions of about 5 to 700 mm Hg. 
Carrying out the processing as described above will reduce or completely 
eliminate raw material monomers remaining in the polycarbonate. 
In addition, methods other than those which manufacture by reacting an 
aromatic dihydroxy compound with a carbonate precursor as described above 
exist in which a compounds having hydroxyl groups are reacted to form 
polycarbonate resins. For example, a polycarbonate having an arbitrary 
amount of terminal hydroxyl groups can be readily obtained by adding 
bisphenol A to a carbonate resin and mixing in an extruder. Various 
aromatic dihydroxy compounds bearing at least three phenolic hydroxy 
groups used in polycarbonate manufacturing previously cited as well as 
water can be cited as examples of compounds having such hydroxyl groups. 
The metallic impurities present in aromatic polycarbonates which have a 
detrimental effect in terms of discoloration can be transition metals. 
Specifically, these are the metals Ti, Fe, Cr, Cu, Zn, V, Mo, Co, etc. 
These metals are frequently ionized within the polycarbonate and exist as 
ionized compounds. Ionized metal species readily form salts with other 
compounds (minute amounts of organic and inorganic compounds within the 
polycarbonate), leading to the formation of complexes. These metals or 
metal-ion compounds promote discoloration of the polycarbonate and lead to 
a reduction in molecular mass. Furthermore, these metallic ions form 
halogenides, for example, chlorides. It is well known that chlorine 
remains in polycarbonates [manufactured using] the halogen method. For 
example, Japan Examined Patent Publication (Kokoku) Sho 59-22743 indicates 
that this residual amount is 0.005 parts by weight per 100 parts by weight 
of polycarbonate. Such a large quantity of chlorine readily reacts with 
metals to form chlorides, and not only promotes thermal decomposition, but 
also worsens resistance to hydrolysis. In such polycarbonates manufactured 
using the phosgene method, the deactivating agent formulation should be 
optimized by giving careful consideration to the amount of impurities 
present. On the other hand, in aromatic polycarbonates containing hydroxyl 
groups manufactured using melt methods, there is the possibility of 
promoting discoloration by metals or metallic ions reacting with terminal 
hydroxyl groups in the melt during polycarbonate manufacturing as well as 
during resin formation. Metal impurities other than transition metals can 
also be expected to have a similar detrimental effect. Specifically, Al, 
B, Sn as well as Sb which display Lewis acid characteristics can be cited. 
Contamination with these metals may be due to the raw materials used, or 
occur during the manufacturing stage and/or forming. 
Compounds of iron are particularly troublesome in causing the polymer to 
have an increased yellow index after dwell and develop haze after 
hydrolysis test. The level of iron is not critical but haze and yellowing 
can occur when iron compounds calculated as iron are present in the 
polycarbonate in a level as low as 0.01 ppm. When the level of iron 
reaches 0.02 to 0.03 ppm without the appropriate level of phosphorous acid 
present, the haze level after hydrolysis makes the composition 
unacceptable for critical applications. When the level of iron compounds 
calculated as iron is at the level of 0.1, 0.2, or 0.3 ppm it is critical 
that the appropriate level of deactivating agent be present in the 
composition to meet the exacting standards of these critical applications. 
Thus, minute quantities of the iron compounds calculated as iron at any 
level can be detrimental to meeting critical quality standards of exacting 
applications, but presence of deactivating agent within the limits set 
forth herein surprisingly negates the melt polycarbonate quality issues 
caused by the presence of iron compounds. 
The aromatic polycarbonate resin composition of one of the embodiments of 
this invention is characterized in that it contains phosphorous acid 
together with an aromatic polycarbonate resin as described above. It is 
desirable that the proportion of phosphorous acid per mole of impurity 
metals contained in the aromatic polycarbonate resin be at least 1 mole, 
more preferable that it be at least 3 moles, and even more preferable that 
it be at least 5 moles, and further, that it be less than 100 moles, more 
preferable that it be less than 50 moles, and even more preferable that it 
be less than 25 moles. If more phosphorous acid than that described above 
is added, acceptable thermal stability can be maintained, but there will 
be a marked drop in resistance to hydrolysis. It is especially desirable 
that this amount of phosphorous acid be less than 2 ppm of aromatic 
polycarbonate resin. Consequently, controlling the purity of the aromatic 
polycarbonate resin itself is important. In addition, in the final 
manufacturing stage in the melt method, obtaining the final product by 
adding such minute amounts of phosphorous acid from the extruder (together 
with other additives) during the time when the polycarbonate resin is 
molten and then pelletizing is extremely effective from the viewpoint of 
the final product being thermally stable and the pellets themselves having 
acceptable color. 
The aromatic polycarbonate resin composition of a second embodiment of the 
present invention is characterized by containing a thioether compound 
together with the aforementioned aromatic polycarbonate resin. Thioether 
compounds eliminate the effect of metal impurities and exert an effect on 
thermal stability at high temperatures, and particularly on color tone 
stability. Examples of thioether compounds include 
tetrakis(methylene-3-dodecylthiopropionate)methane and 
ditridecylthio-propionate. The thioether compound should be contained in 
an amount of 1 mole or more, and preferably 50 moles or more, per mole of 
the metal impurities contained in the aromatic polycarbonate resin (and 
preferably per mole of iron), with an amount of 100 moles or more being 
particularly preferred, and it should be contained in an amount of 1,000 
moles or less, and preferably 800 moles or less, with an amount of 500 
moles or less being particularly preferred. If a greater amount is added, 
favorable thermal stability cannot be maintained, and hydrolysis 
resistance will markedly decrease. An amount of less than 500 ppm with 
respect to the aromatic polycarbonate resin is particularly preferred, and 
accordingly, control of the purity of the polycarbonate itself is 
important. Moreover, in the final manufacturing stage of the melt method, 
it is extremely effective if this thioether compound is added from an 
extruder (together with other additives) while the polycarbonate resin is 
in a molten state and it is then pelletized to obtain the final product, 
from the standpoint of the thermal stability of this final product and 
favorable color tone of the pellets themselves. 
The aromatic polycarbonate resin composition of a third embodiment of the 
present invention is characterized by containing a phosphite diester 
together with the aforementioned aromatic polycarbonate resin. Phosphite 
diesters eliminate the effect of metal impurities and exert an effect on 
thermal stability at high temperatures, and particularly on color tone 
stability. An example of such phosphite diesters is the compound having 
the formula below: 
EQU R.sup.d O--P(OR.sup.e)OH 
In the formula, Rd and Re are independent alkyl, aryl, or alkylaryl groups. 
Preferred examples include diphenyl hydrogenphosphite, 
bis(nonylphenylphenyl)hydrogenphosphite, 
bis(2,4-di-t-butylphenyl)hydrogenphosphite, dicresyl hydrogenphosphite, 
and bis(p-t-butylphenyl)hydrogenphosphite. These substances may be used 
individually or in combinations of two or more. Phosphite diesters having 
aromatic groups are more preferred. 
The phosphite diester should be contained in an amount of 1 mole or more, 
and preferably 50 moles or more, per mole of the metal impurities 
contained in the aromatic polycarbonate resin and preferably per mole of 
iron, with an amount of 100 moles or more being particularly preferred, 
and it should be contained in an amount of 1,000 moles or less, and 
preferably 800 moles or less, with an amount of 500 moles or less being 
particularly preferred. If a greater amount is added, favorable thermal 
stability cannot be maintained, and hydrolysis resistance will markedly 
decrease. An amount of less than 500 ppm with respect to the aromatic 
polycarbonate resin is particularly preferred, and accordingly, control of 
the purity of the polycarbonate itself is important. Moreover, in the 
final manufacturing stage of the melt method, it is extremely effective if 
this phosphite diester is added from an extruder together with other 
additives while the polycarbonate resin is in a molten state and is then 
pelletized to obtain the final product, from the standpoint of the thermal 
stability of this final product and favorable color tone of the pellets 
themselves. 
The aromatic polycarbonate resin composition of a fourth embodiment of the 
present invention is characterized by the fact that said composition 
contains a nitrogen-containing heavy metal deactivating agent together 
with the above mentioned aromatic polycarbonate resin. This 
nitrogen-containing heavy metal deactivating agent eliminates the effects 
of metal impurities, and thus has an effect on the thermal stability at 
high temperatures, and especially on the stability of the hue of the 
resin. Such nitrogen-containing heavy metal deactivating agents are 
nitrogen-containing organic compounds which are commercially marketed as 
heavy metal deactivating agents. For example, such compounds are marketed 
under the commercial names of CDA-6 and ZS-90 by Asahi Denka K.K. 
The above mentioned nitrogen-containing heavy metal deactivating agent is 
added at the rate of 10 ppm or greater, preferably 30 ppm or greater, and 
even more preferably 50 ppm or greater, but 500 ppm or less, preferably 
300 ppm or less, and even more preferably 200 ppm or less, relative to the 
weight of the above mentioned (A) aromatic polycarbonate resin. If a 
larger amount is added, the thermal stability can be favorably maintained; 
however, the resistance to hydrolysis drops conspicuously. Control of the 
purity of the polycarbonate itself is important. A process in which such a 
small amount of a nitrogen-containing heavy metal deactivating agent is 
added from the extruder (together with other additives) while the 
polycarbonate resin is in a molten state in the final stage of manufacture 
of the melt process, after which the final product is obtained by 
pelletization, is extremely effective from the standpoint of thermal 
stability of the final product and favorable hue of the pellets 
themselves. 
In addition to the components described above, the resin composition of 
this invention can be further blended with thermal stabilizers, acid 
scavengers, weathering stabilizers, mold release agents, pigments, dyes, 
strengtheners, bulking agents, flame retardants, lubricants, plasticizers, 
anti-static agents, etc. 
Thermal stabilizers are used to further thermally stabilize the aromatic 
polycarbonate. Phosphorous esters and/or phenolic antioxidants can be 
used. Compounds represented by, for example, the formula 
EQU P(OR.sup.c).sub.3 
wherein R.sup.c represents an alicyclic carboxylic group, aliphatic 
carboxylic group or aromatic carboxylic group, each of which may be 
identical or different, can be cited as examples of phosphorous esters. 
Specifically, trialkyl phosphites such as 
trimethyl phosphite, 
triethyl phosphite, 
tributyl phosphite, 
trioctyl phosphite, 
tris-(2-ethylhexyl)phosphite, 
trinonyl phosphite, 
tridecyl phosphite, 
trioctadecyl phosphite, 
tristearyl phosphite, 
tris-(2-chloroethyl)phosphite, 
tris-(2,3-dichloropropyl)phosphite, etc.; 
tricycloalkyl phosphites such as 
tricyclohexyl phosphite, etc.; 
triaryl phosphites such as 
triphenyl phosphite, 
tricresyl phosphite, 
tris-(ethylphenyl)phosphite, 
tris-(2,4-di-t-butylphenyl)phosphite, 
tris-(nonylphenyl)phosphite, 
tris-(hydroxyphenyl)phosphite, etc.; and 
arylalkyl phosphites such as 
phenyldidesyl phosphite, 
diphenyldesyl phosphite, 
diphenylisooctyl phosphite, 
phenylisooctyl phosphite, 
2-ethylhexyldiphenyl phosphite, etc., 
can be cited as examples. 
Further, distearylpentaerythryl diphosphite, 
bis-(2,4-di-t-butylphenyl)-pentaerythryl diphosphite, etc., can also be 
cited. 
These compounds can be used alone or in combination. 
Among these, it is preferable to use aromatic phosphorous esters, in 
particular, tris-(2,4-di-t-butylphenyl)phosphite. 
Any phenolic compound normally used as an antioxidant in this field can be 
used, in particular, hindered phenolic compounds, specifically, 
n-octadecyl-3-(4-hydroxy-3',5'-di-t-butylphenyl)-proprionate, 
methane 
tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)-proprionate], 
butane 1,1,3-tris-(2-methyl-4-hydroxy-5-t-butylphenyl), 
distearyl-(4-hydroxy-3-methylphenyl-5-t-butyl)-benzylmalonate, 
4-hydroxymethyl-2,6-di-t-butylphenol, etc., 
can be cited as examples. These may be used alone or two or more compounds 
may be used in combination. 
Thermal stabilizers are used as necessary according to the amount of 
deactivating agent (B) as well as the purity of the aromatic polycarbonate 
(A) component (in particular, depending on the amount of metallic ions 
present). The addition of such deactivating agents is mainly effective 
against decreases in molecular weight during heating. When phosphorous 
esters are used alone, the amount of additive is normally less than 0.1 
part by weight for 100 parts by weight of aromatic polycarbonate, 
preferably less than 0.05 parts by weight, and more preferably less than 
0.03 parts by weight, and further, it preferably at least 0.0005 parts per 
weight, and more preferably, at least 0.001. When phenolic antioxidants 
are used alone, the amount is less than 0.1 parts by weight for 100 parts 
by weight of aromatic polycarbonate, preferably less than 0.05 parts by 
weight, and more preferably less than 0.03 parts by weight; and further, 
at least 0.0005 parts by weight, and more preferably at least 0.001 parts 
by weight. Used in this range, these amounts are optimal to exhibit the 
effects of improving thermal stability, avoiding hydrolysis as well as 
preventing mold contamination. In addition, phosphorous esters and 
phenolic antioxidants can be used in combination. 
Compounds having, for example, at least one epoxy group in a single 
molecule are used as acid scavengers. Specifically, 
epoxidized soybean oil, 
epoxidized linseed oil, 
phenylglycidyl ether, 
allylglycidyl ether, 
t-butylphenylglycidyl ether, 
3,4-epoxyhexylmethyl-3',4'-epoxycyclohexyl carboxylate, 
3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-6'methylcyclohexyl 
carboxylate, 
2,3-epoxycyclohexylmethyl-3',4'-epxycyclohexyl carboxylate, 
4-(3,4-epoxy-5-methylcyclohexyl)-butyl-3'4'-epoxycyclclohexyl carboxylate, 
3,4-epoxycyclohexyl ethylene oxide, 
cyclohexylmethyl-3,4-epoxycyclohexyl carboxylate, 
3,4-epoxy-6-methylcyclohexylmethyl-6'-methylcyclohexyl carboxylate, 
bisphenol A diglycidyl ether, 
tetrabromo-bisphenol A glycidylether, 
diglycidyl esters of phthalic acid, 
diglycidyl esters of hexahydrophthalic acid, 
bis-epoxy-cyclopentadienyl ether, 
bis-epoxy-ethylene glycol, 
bis-epoxy-cyclohexyladipate, 
butadiene epoxide, 
tetraphenyl ethylene epoxide, 
octylepoxytallate, 
epoxidized polybutadiene, 
3,4-methyl-1,2-epoxycyclohexane, 
3,5-dimethyl-1,2-epoxycyclohexane, 
3-methyl-5-t-butyl-1,2-epoxycyclohexane, 
octadecyl-2,2-dimethyl-3,4-epoxycyclohexyl carboxylate, 
N-butyl-2,2-dimethyl-3,4-epoxycyclohexyl carboxylate, 
cyclohexyl-2-methyl-3,4-epoxy-5-methylcyclohexyl carboxylate, 
octadecyl-3,4-epoxycyclohexyl carboxylate, 
2-ethylhexyl-3',4'-epoxycyclohexyl carboxylate, 
4,6-dimethyl-2,3-epoxycyclohexcyl-3'4'-epoxycyclohexyl carboxylate, 
4-5-epoxy-tetrahydrophthalic anhydride, 
3-t-butyl-4,5-epxoy-tetrahydrophthalic anhydride, 
diethyl-4,5-epoxy-cis-1,2-cyclohexyl dicarboxylate, 
di-n-butyl-3-t-butyl-4,5-epoxy-cis-1,2-cyclohexyl dicarboxylate, etc., 
can be cited as examples. Among these, it is preferable to use alicyclic 
epoxy compounds, and in particular, it is preferable to use 
3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexyl carboxylate. These 
compounds may be used alone or in mixtures of two or more compounds 
together. 
The main purpose of acid scavengers is to scavenge components that exhibit 
acidity, primarily so that they do not to have a detrimental impact on 
resistance to hydrolysis. Acid scavengers are added as necessary 
corresponding to the amount of added deactivating agent (B) and the amount 
of added thermal deactivating agent described above. Normally, less than 
0.1 parts by weight for 100 parts by weight of aromatic polycarbonate is 
added, preferably less than 0.05 parts by weight, and more preferably, 
less than 0.03 parts by weight; and further, at least 0.0005 parts by 
weight and preferably 0.001 parts by weight. 
Weathering stabilizers are used when applications demand weather 
resistance. Benzotriazole-related compounds can be cited as examples of 
weathering stabilizers. Specifically, 
2-(2'-hydroxy-5'-methyl-phenyl) benzotriazole, 
2-(2'-hydroxy-3',5'-di-t-butyl-phenyl) benzotriazole, 
2-(2'-hydroxy-3'-t-butyl-5'-methyl-phenyl)-5-chlorobenzotriazole, 
2-(2'-hydroxy-5'-t-octylphenyl) benzotriazole, 
2-(2'-hydroxy-3',5'-di-t-amylphenyl) benzotriazole, 
2-[2'-hydroxy-3'-(3",4",5",6"-tetrahydrophthalomethyl)-5'-methylphenyl]ben 
zotriazole, 
2,2'-methylene-bis[4-(1,1,3,3-tetramethylbutyl)-6-(2H-benzotriazole-2-il) 
phenol], etc., can be cited. 
The amount of weathering stabilizer is normally less than 0.5 parts by 
weight for 100 parts by weight of aromatic polycarbonate, preferably less 
than 0.4 parts by weight, and more preferably less than 0.3 parts by 
weight; and further, is at least 0.05 parts by weight, and more 
preferably, at least 0.1 parts by weight. 
As for mold release agents, at least one compound selected from among the 
group consisting of partial or full esters with aliphatic carboxylic acids 
and polyhydric alcohols, silicone-related compounds as well as 
olefin-related compounds can be cited as examples. There are no particular 
restrictions on the polyhydric alcohol, and dihydric, trihydric, 
tetrahydric, pentahydric, and hexahydric [alcohols] can be used, but 
ethylene glycol, glycerin, trimethylolpropane, pentaerythritol, etc., are 
preferred. There are no particular restrictions on the aliphatic 
carboxylic acid, and both saturated and unsaturated aliphatic carboxylic 
acids can be used. For example, hydrogenated animal oils can be used. 
Saturated monovalent fatty acids are preferred as carboxylic acids, , and 
ones having from 12 to 24 carbon atoms are especially preferred. If the 
number of carbon atoms is fewer than the aforementioned range, there is a 
tendency for the thermal stability of the resin composition to deteriorate 
compared to ones in the aforementioned range, and in addition, gas 
generation readily occurs. On the other hand, if the number of carbon 
atoms is greater than the aforementioned range, there is a tendency for 
the mold release properties of the resin composition to deteriorate 
compared to ones within the aforementioned range. Specifically, dodecylic 
acid, dodecylic acid, myristic acid, pentadecylic acid, palmitic acid, 
heptadecylic acid, stearic acid, nonadecanoic acid, arachic acid, behenic 
acid, lignoceric acid, etc., can be cited as examples of aforementioned 
aliphatic carboxylic acid. Silicone oil can be cited as a silicone-related 
compound. And .alpha.-olefin oligomer can be cited as a olefin-related 
compound. 
Mold release agents are used in situations that demand mold releasability 
and the amount is normally less than 0.5 parts by weight for 100 parts by 
weight of aromatic polycarbonate, preferably less than 0.4 parts by 
weight, and more preferably less than 0.3 parts by weight; and further, is 
at least 0.005 parts by weight, and more preferably, at least 0.01 parts 
by weight. 
There are no particular restrictions on the method used to manufacture the 
resin compound of this invention, and ordinary methods can be used 
satisfactorily. Nevertheless, in general, melt mixture methods are 
preferable. Small amounts of catalyst can be used, but are generally 
unnecessary. An extruder, Bumbury mixer, roller, kneader, etc., can be 
specifically cited as equipment, and these can be operated batch-wise or 
continuously. 
This invention will be explained based on the examples below, but this 
invention is not limited to these examples. 
It should also be noted that the examples and comparative examples used the 
following constituents. 
(A) a polycarbonate having hydroxyl groups as its end groups was fabricated 
as follows: 
0.44 kilomole of bisphenyl A (BPA) as the aromatic dihydroxyl compound and 
0.46 kilomoles of diphenyl carbonate as the carbonate diester were 
prepared in a 250-liter tank-type mixing vessel, and after evacuation and 
replacement with nitrogen, were melted at 140.degree. C. 
Next, the temperature of this mixture was raised to 180.degree. C. and 
0.000176 mole of sodium hydroxide (4.times.10-7 mole/mole of bisphenol A) 
and 0.11 mole of tetramethyl ammonium hydroxide (2.5.times.10-4 mole/mole 
of bisphenol A) were added as catalysts, and the mixture was agitated for 
30 minutes. 
Next, the temperature was raised to 210.degree. C. simultaneous with a 
gradual reduction in pressure to 200 mm Hg. After 30 minutes, the 
temperature was raised to 240.degree. C. simultaneous with a gradual 
reduction in pressure to 15 mm Hg. The amount of phenol distilled off was 
measured while keeping the temperature and pressure constant. At the point 
when no further phenol was distilled off, the mixture was returned to 
atmospheric pressure under nitrogen. The time required for the reaction 
was one hour. The limiting viscosity [.eta.] of the reaction product so 
obtained was 0.15 dl/g. 
A gear pump was used to raise the pressure of this reaction product, which 
was then fed into a centrifugal thin-film evaporator which promotes the 
reaction. The temperature and pressure of the thin-film evaporator were 
controlled at 270.degree. C. and 2 mm Hg, respectively. It is then fed via 
a gear pump from the bottom of the evaporator into a twin-screw horizontal 
agitated polymerization vessel (L/D=3, agitation vane rotational 
diameter=220 mm, internal volume=20 liters) controlled at 293.degree. C. 
and 0.2 mm Hg and was polymerized with a dwell time of 30 minutes. 
Next, a gear pump was used to feed this polymer in the molten state into a 
twin-screw extruder (L/D=17.5, barrel temperature=285.degree. C.) where 
0.7 ppm of p-butyl-toluenesulfonate per part of resin is added and mixed 
in. It is then made into pellets by extruding in strand form through a die 
and cutting using a cutter. 
The intrinsic viscosity [.eta.] of the polymer so obtained was 0.51 dl/g. 
Phenolic terminal groups made up 12% of the total end groups. In addition, 
analysis using the flameless atomic absorption spectroscopy method 
indicated the amount of metal contained as metallic impurities to be 0.025 
ppm calculated as iron. This polycarbonate is designated as PC. 
It should also be noted that the OH-group concentration of the phenolic end 
groups was determined by measuring the absorption strength at 3,600 cm-1 
using Fourier Transform Infrared Spectroscopy (FTIR). The concentration of 
total end groups was measured by determining the original average 
molecular weight based on a value for intrinsic viscosity (IV) measured in 
a methylene chloride solvent. The Schnell formula, IV=1.23.times.10-4M0.83 
(where M=viscosity average molecular weight), was used to convert this IV 
value to average molecular weight. 
(B)(1) Phosphorous acid 
A 50% aqueous solution was used (values in Table 1 are amounts of 
phosphorous acid)

EXAMPLE 1 AND COMATIVE EXAMPLES 1 TO 3 
(1) Manufacture of the Resin Composition 
As shown in Table 1, component (B)(1) phosphorous acid was mixed with 100 
parts of the polycarbonate (PC) obtained as described above. This was 
melted and mixed at 280.degree. C. using a single-screw extruder 
(L/D=17.5), and formed into pellets. 
(2) Evaluation 
Evaluation was performed as follows. 
Yellow Index 
A 150-ton molding machine manufactured by Okuma Corporation was used to 
form an injection molded article with a thickness of 3.0 mm at a cylinder 
temperature of 280.degree. C. and a mold temperature of 80.degree. C. 
Using this molded article, X, Y, and Z values were measured using the 
transmissive method with an ND-1001 DP Color and Color Difference Meter 
manufactured by Nippon Denshoku Kogyo Co., Ltd., and the yellow index (YI) 
was determined. 
YI=100.times.(1.277 X-1.060 Z)/Y 
Optical Transmissivity 
Optical transmissivity was measured using the above-mentioned molded 
article according to the method set forth in ASTM standard D-1003. 
Haze 
The haze in the above-mentioned molded article was measured using an 
NDH-200 manufactured by Nippon Denshoku Kogyo Co., Ltd. 
Resistance to Hydrolysis 
The above-mentioned molded article was placed in an autoclave filled with 
pure water, placed in an oven at 120.degree. C. and aged for five days. 
After the test period, the haze was measured and taken as an indicator of 
hydrolysis. 
Dwell-Time Stability 
The resin was retained within the cylinder of the above-mentioned molding 
machine for 15 hours at a temperature of 320.degree. C. It was then molded 
at this temperature and the yellow index (YI) measured. 
The results of the above evaluation are given in Table 1. 
EXAMPLES 2 TO 6 AND COMATIVE EXAMPLES 4 TO 6 
(1) Manufacture of the Resin Composition 
Phosphorous acid and the iron (III) salt of acetylacetone (described as the 
amount of iron in Table 1) was mixed with the polycarbonate (PC) in the 
proportions indicated in Table 1. A resin composition was manufactured in 
a manner identical to Example 1 and pellets were formed. 
(2) Evaluation 
An evaluation was performed in a manner identical to Example 1. The results 
are given in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Examples Comparative Examples 
1 2 3 4 5 6 1 2 3 4 5 6 
__________________________________________________________________________ 
Amount of iron additive 
0 0.1 
0.1 
0.1 
0.1 
0.1 
0 0 0 0.1 
0.1 
0.1 
(ppm) 
Phosphorous acid (ppm) 
1.5 
0.5 
0.9 
1.7 
4.9 
8.5 
0 4.5 
9 0 26 52 
Phosphorous acid/iron* 
41 3 5 10 29 50 -- 
123 
246 
-- 
150 
300 
(Molar ratio) 
YI (initial) 1.4 
1.8 
1.6 
1.4 
1.3 
1.3 
1.5 
1.3 
1.2 
2.9 
1.3 
1.3 
YI (after dwell) 
1.8 
2.2 
2.1 
1.9 
1.7 
1.7 
2.1 
1.6 
1.3 
4.3 
1.7 
1.6 
Haze (initial) 
0.1 
0.2 
0.2 
0.2 
0.2 
0.2 
0.2 
0.1 
0.1 
0.3 
0.2 
0.2 
Haze (after hydrolysis test) 
2.0 
5 4.9 
4.8 
30.1 
68.3 
0.3 
25.3 
65 8.6 
&gt;90 
&gt;90 
__________________________________________________________________________ 
*Molar ratio of phosphorous acid with respect to total amount of iron 
[iron contained in the PC resin and added iron 
(B)(2) Thioether Compound 
Tetrakis(methylene-3-dodecylthiopropionate)methane 
EXAMPLE 7 AND COMISON EXAMPLES 7 AND 8 
(1) Manufacturing of Resin Composition 
The thioether compound of component (B)(2) was blended with polycarbonate 
(PC) obtained as described above, mixed as shown in Table 2, and 
melt-kneaded at 280.degree. C. in a uniaxial extruder (L/D=17.5) to make 
pellets. 
(2) Evaluation 
An evaluation was performed in a manner identical to Example 1. The results 
are given in Table 2. 
The above evaluation results are shown in Table 2. 
EXAMPLES 8 AND 9 AND COMISON EXAMPLES 9 AND 10 
(1) Manufacturing of Resin Composition 
0.1 ppm of iron (III) salt of acetyl acetone (the amount thereof is shown 
in Table 2 as iron) and the amounts shown in Table 2 of thioether 
compounds were mixed with polycarbonate (PC), and resin compositions were 
manufactured in the same manner as in Example 7 and made into pellets. 
(2) Evaluation 
Evaluation was conducted in the same manner as in Example 1. The results 
are shown in Table 2. 
TABLE 2 
______________________________________ 
Examples Comparison examples 
7 8 9 7 8 9 10 
______________________________________ 
Amount of iron added 
0 0.1 0.1 0 0 0.1 0.1 
(ppm) 
Thioether compound (ppm) 
50 120 240 0 750 0 3600 
Thioether compound/iron* 
100 50 100 -- 1500 -- 1500 
(Molar ratio) 
YI (initial period) 
1.4 1.5 1.4 1.5 1.2 2.9 1.5 
YI (after retention) 
1.6 1.8 1.8 2.1 1.4 4.3 1.7 
Haze (initial period) 
0.2 0.3 0.3 0.2 0.2 0.3 0.3 
Haze (after hydrolysis test) 
5.1 7.3 12.6 0.3 75.3 8.6 &gt;90 
______________________________________ 
*Molar ratio of thioether compound to total amount of iron [iron containe 
in PC resin and added iron (moles) 
(B)(3) Phosphite Diester 
Diphenyl hydrogenphosphite 
EXAMPLES 10 AND 11 AND COMISON EXAMPLES 11 and 12 
(1) Manufacturing of Resin Composition 
The phosphite diester of component (B)(3) was blended with polycarbonate 
(PC) obtained as described above, mixed as shown in Table 3, and 
melt-kneaded at 280.degree. C. in a uniaxial extruder (L/D=17.5) to make 
pellets. 
(2) Evaluation 
Evaluation was conducted in the same manner as in Example 1. The results 
are shown in Table 3. 
EXAMPLES 12 AND 13 AND COMISON EXAMPLES 13 AND 14 
(1) Manufacturing of Resin Composition 
0.1 ppm of iron (III) salt of acetyl acetone (the amount thereof is shown 
in Table 1 as iron) and the amounts shown in Table 3 of the phosphite 
diester of component (B)(3) were mixed with polycarbonate (PC), and resin 
compositions were manufactured in the same manner as in Example 10 and 
made into pellets. 
(2) Evaluation 
Evaluation was conducted in the same manner as in Example 1. The results 
are shown in Table 3. 
TABLE 3 
__________________________________________________________________________ 
Examples Comparison examples 
10 11 12 13 11 12 13 14 
__________________________________________________________________________ 
Amount of iron added (ppm) 
0 0 0.1 
0.1 
0 0 0.1 
0.1 
Phosphite diester (ppm) 
5 10 10.4 
52 0 150 0 780 
Phosphite diester/iron* 
50 100 
20 100 
-- 1500 
-- 1500 
(Molar ratio) 
YI (initial period) 
1.4 
1.3 
1.6 
1.4 
1.5 
1.3 2.9 
1.3 
YI (after retention) 
1.6 
1.5 
1.8 
1.6 
2.1 
1.4 4.3 
1.5 
Haze (initial period) 
0.2 
0.2 
0.3 
0.2 
0.2 
0.2 0.3 
0.2 
Haze (after hydrolysis test) 
2.4 
5.1 
9.3 
12.3 
0.3 
&gt;90 8.6 
&gt;90 
__________________________________________________________________________ 
*Molar ratio of phosphite diester to total amount of iron [iron contained 
in PC resin and added iron (moles) 
(B)(4) Nitrogen-Containing Heavy Metal Deactivating Agent 
Adekastab ZS-90 (commercial name, nitrogen-containing organic compound, 
manufactured by Asahi Denka K.K.). 
EXAMPLE 14 AND COMATIVE EXAMPLE 15 
(1) Manufacture of Resin Composition 
Component (B)(4), i.e., a nitrogen-containing heavy metal deactivating 
agent, was added as shown in Table 4 to the polycarbonate (PC) thus 
obtained, and this mixture was melted and kneaded at 280.degree. C. using 
a single-shaft extruder (L/D=17.5), thus producing pellets. 
(2) Evaluation 
Evaluation was conducted in the same manner as in Example 1. The results 
are shown in Table 4. 
EXAMPLES 15 AND 16 AND COMATIVE EXAMPLES 16 AND 17 
(1) Manufacture of Resin Composition 
An iron (III) salt of acetylacetone (amount of iron shown in Table 4) was 
added to the polycarbonate (PC) at the rate of 0.1 ppm, and a 
nitrogen-containing heavy metal deactivating agent was added in the amount 
shown in Table 4. A resin composition was then manufactured and pellets 
were prepared in the same manner as in Example 1. 
(2) Evaluation 
Evaluation was conducted in the same manner as in Example 1. The results 
are shown in Table 4. 
TABLE 4 
______________________________________ 
Example Comparative Example 
14 15 16 15 16 17 
______________________________________ 
Amount of iron added 
0 0.1 0.1 0 0.1 0.1 
(ppm) 
Nitrogen-containing heavy 
50 100 300 0 0 1000 
metal deactivating agent 
(ppm) 
YI (Initial) 1.4 1.8 1.6 1.5 2.9 1.5 
YI (After residence) 
1.9 2.1 1.9 2.1 4.3 1.8 
Haze (Initial) 
0.2 0.3 0.3 0.2 0.3 0.4 
Haze (After hydrolysis test) 
1.2 4.6 5.3 0.3 8.6 &gt;90 
______________________________________ 
The resin composition of this invention has excellent thermal stability, 
color stability, and resistance to hydrolysis, and further, mold 
contamination during long-term molding is extremely low. Consequently, it 
is ideal for applications demanding transparency, for example, optical 
applications such as lenses, optical disks, etc., or building materials 
such as sheets, films, etc. In addition, by exploiting its stability, it 
can also be used as a strengthened polycarbonate resin formed by mixing 
with fillers, as an alloy with other polymers, etc., and has extremely 
high industrial utilization value.