CA1131651A - Thermally stable polycarbonate compositions - Google Patents

Abstract

ABSTRACT OF THE INVENTION
Thermally stable polycarbonate compositions are obtained by admixing with a high molecular weight aromatic polycarbonate resin a stabilizing amount of a hindered phenol phosphite.

Description

~ f3~ 8CH-29~3 This invention relates to thermally stable polycarbonate compositions comprisiny an admixture of an aromatic polycarbonate and a stabiliæing amount of a hindered phenol phosphite.
BACKGROUND OF THE INVENTION
In the past, much effort has been expended in preparing I thermally stable polycarbonate compositions which would be color stable at elevated temperatures and particularly at the high molding temperatures generally employed to prepare molded polycarbonate articles. Many different additives have been found that the quite suitable for rendering polycarbonates heat and color stable. Particularly useful are triorgano phosphites such as are disclosed in U.S. Patent 3,305,520 - Fritz et al, issued February 21, 1967. In addition, U.S. Patent 3,729,440 - Liberti, issued April 24, 1973 and U.S. Patent 3,953,338 - Straus et al, issued April 27, 1976 disclose thermally stable aromatic poly-carbonates containing a phosphinite and an epoxy compound.
Further, U.S. Patent 3,794,629 ~ Eimers et al, issued February 26, 1974 discloses chemically stable aromatic polycarbonates containing oxetane phosphites and U.S. Patent 3,978,020 - Liberti, issued August 31, 1976 discloses thermally stable aromatic poly-carbonates containing phosphonites which include epoxy compounds.
Polycarbonates are also used for producing bottles; however, these bottles become hazy after sterilization in water or exposure to moisture at elevated temperatures. U.S. Patent 3,839,247 Bialous et al, issued October 1, 1974 discloses a water clear polycarbonate composition which can be used to mold bottles twherein the polycarbonate composition contains an aromatic epoxy or an aliphatic epoxy compound as a stabilizer.
Canadian application Serial No. 343,169, Markezich, filed January 7, 1980, discloses aromatic polycarbonate compositions containing phosphonite oxetanes; Canadian application Serial No. 343,194, Markezich, filed 3anuary 7, 1980, discloses aromatic ~ ' ~

:

~ 6S1 8CH-2963 polycarbonate compositions containing phosphite oxetanes having a hindered phenol; Canadian application Serial No. 343,122, Markezich, filed January 7, 1980, discloses aromatic polycarbonate compositions containing a phosphonite or a phosphonite oxetane each having a hindered phenol; and, Canadian application Serial No. 343,170, Markezich, filed January 7, 1980, discloses aromatic polycarbonate compositions containing dioxane phosphites, each of these Canadian applications being assigned to the same assignee as this case.
DESCRIPTION OF THE INVENTION
It has been discovered that when an aromatic polycarbonate is admixed with a hindered phenol phosphite, the resulting poly-carbonate composition has improved thermal stability as exempli-fied by its resistance to yellowing when subjected to high molding temperatures.
The phosphite compounds that can be used in the present invention are represented by -the general structure:

A ~ 0 ~ I _ (0Rl) (I) ( ORl) wherein Rl can be an alkyl of Cl to C30, an aryl of C6 up to about C30, preferably C6-C12, and alkyls of C~ to C20 which can form mono-cyclic structures; and, A is a hindered phenol represented by the general structure:

; 3 ~ (II) ~4 wherein R2, R3 and R4 can be the same or different and each can independently be hydrogen, halogen or Cl-C4 alkyl provided that neither R2 and/or R4 are hydrogen.

~3~5~ 8CH-2963 !

Ij Thus, Rl in formula I can be unsubstituted and halogen I ~substituted alkyl, aryl, cycloalkyl, aralkyl and alkaryl radicals ~
of about Cl-C30 so that typical phosphites that can be employed ¦
'~in the present invention are those wherein Rl can be alkyl 5¦ such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tertiary butyl, n-amyl, isoamyl, tertiary amyl, n-hexyl, dodecyl, nonyl, and the like; cycloalkyl such as cyclohe~yl, 2-methyl-, cyclohexyl, 4-methylcyclohexyl, 2-ethylcyclohexyl, 4-ethylcyclo-¦ihexyl, 4-isopropylcyclohexyl, and the like; aryl such as phenyl, 10¦¦naphthyl, 2-naphthyl, biphenyl of terphenyl, and the like;
aralkyl such as benzyl, phenylethyl, 2-phenylethyl, l-phenylpropyl ,2-phenylpropyl, and the like; alkaryl such as p-tolyl, m-tolyl, j2,6-xylyl, o-tolyl, p-cumyl, m-cumyl, o-cymyl, mesityl, p-! tertiary butylphenyl, and the like; and, haloaryl such as 2-15 tl chlorophenyl, 2,4,6-trichlorophenyl, 2,4,6-tribromophenyl, and llthe like, wherein the substituted portions thereof can be halogen !~ atoms.
The phosphites of the.invention can be prepared by methods ,iknown to those skilled in the art such as are described in 20~lOrganic Phosphorous Compounds, Vol. 4, edited by G.M. Kosolapoff and L. Maier (1972), pages 255-462,. ~ - --¦~ The.phosphite compounds of the invention are admixed with¦¦the aromatic polycarbonate in a stabilizing amount which is 25 ¦¦ generally on the order of about 0.005 1.0, preferably 0.01-¦,0.50 and optimumly about 0.02-0.20 weight percent, based 1~ 1 I i i'~
~ - 3 ~3~ 8CH-2963 i~ ' i upon the weight of the aromatic polycarbonate.
The aromatic polycarbonate that can be employed in the prac-tice of this invention are homopolymers and copolymers and mix-Itures thereof that are prepared by reacting a dihydric phenol with a carbonate precursor.
The dihydric phenols that ~an be employed are bisphenols such as bist4-hydroxyphenyl)methane, 2,2-bis(4-hydroxyphenyl)propane (bisphenol-A), 2,2-bis(4-hydroxy-3-methylphenyl)propane. 4,4-,!bis(4-hydroxyphenyl)heptane, 2,2-bis (4-hydroxy-3,5-dichlorophenyl) 10 jlpropane~ 2,2-bis(4-hydroxy-3,5- dibromophenyl)propane, etc.;
¦dihydric phenol ethers such as bis(4-hydroxyphenyl)ether, bis(3,5-jldichloro-4-hydroxyphenyl)ether~ etc.; dihydroxydiphenyls such Il as p,p'-dihydroxydiphenyl, 3,3'-dichloro-4,4-dihydroxydiphenyl, ¦letc.; dihydroxyaryl sulfones such as bis(4-hydroxyphenyl)sulfone, 15 ¦I bis(3,5-dimethyl-4-hydroxyphenyl)sulfone, etc.; dihydroxy 3 benzenes, resorcinol, hydroquinone, halo- and alkyl-substituted ¦ dihydroxybenzenes such as 1,4-dihydroxy-2,5-dichlorobenzene, 1,4-dihydroxy-3-methylbenzene, etc.; and dihydroxy diphenyl sulfoxides such as bis(4-hydroxyphenyl)sulfoxide, bis(3,5 dibromo-¦
20 ~ 4-hydroxyphenyl)sulfoxide, etc. A variety of additional dihydric ¦
¦ phenols are also available to provide carbonate polymers such as 3 are disclosed in U.S. Patents 2,999,835, 3,023,365 and 3,153,008.
Also suitable for preparing the aromatic carbonate polymers are copolymers prepared from the above dihydric phenols copolymerized with halogen-containing dihydric phenols such as 2,2-bis(3,5-dichloro-4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo-4-hydroxy-I phenyl)propane, etc. It is also possible to employ two or more l,~ different dihydric phenols or a copolymer of a dihydric phenol 11 . I
l~ with a glycol or with hvdroxy or acid terminated polyester, or 30 '~, with a dibasi.c acid in the ev~nt a carbonate copolymer or inter-polymer rather than a homopolymer is desired Eor use in the pre-I paration of the aromatic polycarbonates of this invention as -~ell as ~lends of any of the above materials.

, , ... .. ._................... ........ _.. _,_ . .... _ _.. . ...... .... .!

i51 8c~-2g~3 , ' The carbonate precursor can be either a carbonyl halide, a ~carbonate ester or a haloformate. The carbonyl halides which can be employed are carbonyl bromide, carbonyl chloride and mixtures thereof. Typical of the carbonate esters that can be employed are diphenyl carbonate, di-(halophenyl) carbonates such as di-(chlorophenyl) carbonate, di-(bromophenyl) carbonate, di-(trichlorophenyl) carb<nate, di-(tribromophenyl) carbonate, etc., ¦ di-(alkylphenyl) carbonate such as di-(tolyl) carbonate, etc., di-!!(naphthyl) carbonate, di-(chloronaphthyl) carbonate, phenyl tolyl ¦¦carbonate, chlorophenyl chloronaphthyl carbonate, etc., or mix- !
¦~tures thereof. The haloformates suitable for use herein include !i bishaloformates of dihydric phenols (bischloroformates of hydro-;lquinone, etc.) or glycols (bishaloformates of ethylene glycol, ,~ineopentyl glycol, polyethylene glycol, etc.~. While other carbon-¦
I ate precursors will occur to those skilled in the art, carbonyl chloride, also known as phosgene, is preferred.
Also included are the polymeric derivatives of a dihydric !~ phenol, a dicarboxylic acid and carbonic acid. These are dis-¦Iclosed in U.S. Patent 3,169,121. ~ ; - ' 1' ¦ The aromatic polycarbonates of this invention are prepared ¦Iby employing a molecular weight regulator, an acid acceptor and a catalyst. The molecular weight regulators which can be employed¦
; include monohydric phenols such as phenol, chroman-I, paratertiary butylphenol, parabromophenol, primary and secondary amines, etc.
Preferably, phenol is e~ployed as the molecular weight regulator.
A suitable acid acceptor can be either an organic or an ¦ inorganic acid acceptor. ~ suitable organic acid acceptor is a tertiary amine and lncludes such materials as pyridine, triethyl-~ amine, dimethylaniline, trlbutylamine, etc. The inorganic acidacceptor can be one which can be either a hydroxide, a carbonate, ~¦ a bicarbonate, or a phosphate of an alkali or alkaline earth ¦~ metal.
1! _ 5 _ ~ 3~ ~`5~ 8C~I-296~ ~

~ The catalysts whlch can be employed can be any of the suit- ¦
¦able catalysts that aid the polymerization of bisphenol~A with phosgene. Suitable catalysts include tertiary amines such as triethylamine, tripropylamine, N,N-dimethylaniline, quaternary ammonium compounds such as tetraethylammonium bromide, cetyl triethylammonium bromide, tetra-n-heptylammonium iodide, tetra-n-propylammonium bromide, tetramethylammonium chloride, tetra-methylammonium hydroxide, tetra-n-butylammonium iodide, benzyl-trimethylammonium chloride and quaternary phosphonium compounds such as n-butyl-~riphenyl phosphonium bromide and mekhyltriphenyl phosphonium bromide.
Also included herein are branched polycarbonates wherein a polyfunctional aromatic compound is reacted with the dihydric phenol and carbonate precursor to provide a thermoplastic randomly branched polycarbonate.
These polyfunctional aromatic compounds contain at least three functional groups which are caxboxyl, carboxylic anhydride, haloformyl or mixtures thereof. Examples of these polyfunctional aromatic compounds include trimellitic anhydride, trimellitic acid, trimellityl trichloride, 4-chloroformyl phthalic anhydride, pyromellitic acid, pyromellitic dianhydride, mellitic acid, melli-¦
tic anhydride, trimesic acid, benzophenonetetracarboxylic acid, benzophenonetetracarboxylic anhydride, and ~he li~e. The preferred polyfunctional aromatic compounds are trimellitic anhydride or trimellitic acid, or their haloformyl derivatives.
Also included herein are blends of a linear polycarbonate and a branched polycarbonate.
DESCRIPTION OF T~E PREFERRED EMBODIMENT
The following examples are set forth to more clearly illus-trate the invention. Unless otherwise specified, parts or per-~ Icents are y weight. - 6 -~1 1 6,~31 ~ethod of Pre arin A New Phos hite- ¦

276 grams (2.94 moles) of phenol and 200 grams (1.47 moles) of 2,4,6-trlmethylphenolwere heated at 50C under nitrogen until melted and then 201.9 grams (1.47 moles) of phosphorous trichloride !
were added dropwise. When the phosphoroustrichloride addition was ~
complete, the mixture was heated to 100C and held at this temperaj ture overnight. Vacuum was applied and unreacted phenol and trimethylphenol were distilled off. The product, diphenyl-(2,4,6-¦
trimethylphenyl~phosphite, was distilled at 165 to 170C at 0.1 mm.Hg. to afford a clear colorless liquid. The proton nuclear magnetic resonance (NMR) analysis showed the methyl protons at

2.27 ~ (9.1 H) and the aromatic protons at 6.80 and 7.15 ~ (11.9 H)~

Structure:
~o--P~o~3~ ' EXP~lPLE 2 Method of Preparing_ A New Phosphite Bis(2,4,6-trimethylphenYl)PhenY1 PhosPhite 103.6 grams (1.1 moles) of phenol and 300 grams (2.2 moles) of 2,4,6-trimethylphenol were heated at 50C under nitrogen until ¦
melted and then 151.1 grams (1.1 moles) of phosphoroustrichloride ¦

were added dropwise. When the phosphoroustrichloride addition was ¦
complete, the mixture was heated at 100C and held at this tem?eral ture overnight. Vacuum was applied and unreacted phenol and tri- ¦
methylphenol distilled off. The product, bis(2,4,6-trimethyl-¦phenyl)phenyl phosphite, was distilled at 187 -o 190C at 0.35 mm.Hg. to afford a clear colorless liquid. The proton NMX showed ¦
the methyl protons at 2.27 ~ (17.2 H) and the aromatic protons at ¦
6.80 and 7.15 ~ (9.8 H). 5 i Structure: ~CH-2963 (~~~

Method of Preparing A New Phosphite:
Tris(2,4~6-trimeth~lphenyl)~hosphite 300 grams (2.2 moles) of 2,4,6-trimethylphenol were heated under nitrogen until melted and then 89.9 grams (0.65 mole) of phosphorous trichloride were added dropwise. When the addition 10 was complete, the mixture was heated to 100C and held at this temperature overnight. Vacuum was applied and unreacted trimethyl~
phenol distilled off. The product, tris(2,4,6-trimethylphenyl) phosphite, was distilled at 1~2-174C at 0.3 mm.Hg. to afford a clear colorless liquid which solidified on standing, mp 92-95~C.
15 The proton NMR showed the methyl protons at 2.23 ~ (27 H) and the aromatic protons at 6.77 ~(6 H).
Structure:
. . , (~ p Method of Pre~arinq A New Phos~hite: -: ~T~
564.7 grams (6 moles) of phenol and 619 grams ~3 moles) of 2,4-di-t-butylphenol were heated at 50C under nitrogen until melted and then 412.1 grams (3 moles) of phosphorous trichloride were added dropwise. When the addition was complete, the mi~ture was heated to 100C and held at this temperature overnight.
Vacuum was applied and unreacted phenol and di-t-butylphenol distilled off. The product, diphenyl-(2,4-di-t-butylphenyl) phosphite,-was distilled at 175 to 180C at 0.15 mm.Hg. to afford !
a pale yellow liquid. The proton NMR showed the t-butyl protons ~t 1. ~19.8 H~ and the aromatic protons at 7.1 ~ (10.2 H).

,. ,.._.. ._.,..

3~6~
~ H-2963 Structure:
`~--P~)2 EX~MPLE 5 Method of Prepar.ing A New Phosphite-Bis(2,4-di-t-butylphen~l)pheriyl phosphite 70.5 grams (0.75 mole) of phenol and 309.5 grams (1.5 moles) of ~,4-di~t-butylphenol were heated at 50C under nitrogen until melted and then 96.2 grams (0.7 mole) of phosphorous trichloride were added dropwise. When the addition was complete, the mixture was heated to 100C and held at this temperature overnight.
Vacuum was applied and unreacted phenol and di-t-butylphenol distilled off. The product, bis(2,4-di-t-butylphenyl)phenyl phosphite, was distilled at 180C at 0.2 mm.Hg. to afford a pale yellow liquid. The proton NMR showed the t-butyl protons at 1.3 ~(33.4 H) and the aromatic protons at 7.2 &r (13.6 H).
Structure:

~ ~ p______ Method of Preparing A New Phosphite:
Diphenyl~(2,6-dimethylphenyl) phosphite 769.8 grams (8.18 moles) of phenol and 500 grams (4.09 moles) of 2,6-dimethylphenol were heated at 50C under nitrogen until melted and then 561.7 grams (4.09 moles) of phosphorous trichlorid~
were added dropwise. When the addition was complete, the mixture was heated to 100C and heid at this temperature overnight.
Vacuum was applied and unreacted phenol and dimethylphenol dis-tilled off. The product, diphenyl-(2,6-dimethylphenyl) phosphite, was distilled at 155C at 0.2 mm.Hg. to afford a clear colorless liquid. The proton NMR showed the methyl protons at 2.33 ~(5.6 and the aromatic protons at 7.00 and 7.17 ~ (13.4 H).

Structure: i ~ ~ P~

Method of Preparing A New Phosphite:
Bis~2!6-dimethylphenyl)phenyl phosphite 280 grams (2.04 moles) of phenol and 500 grams (4.09 moles) ¦of 2,6-dimethylphenol were heated at 50C under nitrogen until melted and then 192 grams (2.04 moles) of phosphorous trichloride ¦
were added dropwise. When the addition was complete, the mixture was heated to 100C and held at this temperature overnight.
Vacuurn was applied and unreacted phenol and dimethylphenol dis-tilled off. The product, bis(2,6-dimethylphenyl)phenyl phosphite, was distilled at 155 to 165 C at 0.2 mm.Hg. to afford a clear colorless liquid. The proton NMR showed the methyl protons at 2.33 ~ (11.4 H) and the aromatic protons at 7.00 and 7.17 (11.6 H).
¦ Structure:

20 ~P-----O

Method of Pre~aring A New Phosphite: ¦
Di-n-octyl-(2,4,5-trimethyl~henyl) phosphite 50 grams (0.14 mole) of diphenyl-(2,4,6-trimethylphenyl) 25phosphite, 40 grams (0.31 mole) of l-octanol, and 0.25 grarns of ¦sodium methoxide were heated under a vacuum of 30 mm.Hg. Phenol jwas removed from the reaction mixture through a Vigreaux coiumn at a pot temperature of 130C and a head temperature of 93C at 30 mrn.Hg. The pot ternperature was increased to 160C and-the pres-sure reduced to 0.2 mm.Hg. to insure complete removal of phenoland excess octanol. The product, di-n-octyl-(2,4,6-trimethyl-phenyl) phosphite, was distilled at 138 to 139C at 0.2 mrn.Hy.

I ' - 10 - I

1131~$~ 8CH-2963 to afford a clear colorless liquid. The proton NMR showed li aliphatic protons centered at 0.85 and 1.3 &~ the methyl groups of the trimethylphenyl moiety at 2.3 &~ the methylene groups adjacent to the oxygen at 3.35 ~, and the aromatic protons at 7.0 Structure:

_____~ ~ ----C8~17)~

EXAMPLE 9 1 , Method of Preparing A New Phosphite:
Di(2-eth 1-1-hexyl)-(2,4,6-trimethylPhenyl) phosPhite Y , _ _ -S0 grams (0.14 mole) of diphenyl-(2,4,~-trimethylphenyl) phosphite, 40 grams (0.31 mole) of 2-ethyl-l-hexanol, and 0.25 grams of sodium methoxide were heated under a vacuum of 30 mm.Hg.
Phenol was removed from the reaction mixture through a Vigreaux-col~mn at a head temperature of 94C at 30 mm.Hg. The pot tempera-ture was increased to 160C and the pressure reduced to 0.2 mm.Hg.¦
to insure complete removal of phenol and excess hexanol. The product, di(2-ethyl-l-hexyl~-)2,4,6-trimethylphenyl) phosphite, was distilled at 150 to 155C at 0.2 mm.Hg. to afford a clear colorless liquid. The proton NMR showed aliphatic protons centered at 0.9 and 1.3 ~, the methyl groups of the trimethylphenyl moiety ~
at 2.25 &, the methylene group adjacent to the oxygen at 3-95 &~ !
and the aromatic protons at 7.0 ~.
Structure:

~ p ~ o CH21CHC4H9)2 - t Method of PreParing A New Phosphite:
Di-2-octvl (2 4,6-trimethYlPhenYl) phosphite -50 grams (0.14 mole) of diphenyl-(2,4,6-trimethylphenyl) phosphite, 40 grams (0.31 mole) of 2-octanol, and 0.25 grams of sodium methoxide were heated under a vacuum of 30 mm.Hg. at loOQC.
, - 11.-Phenol was removed from thé reaction mixture through a Vigreaux column at a head temperature of 94C at 30 mm. Hg. The pot temperature was increased to 160C and the pressure reduced to l 0.2 mm. Hg. to insure complete removal of phenol and excess 51 octanol. The product, di-2-octyl-(2,4,6-trimethylphenyl) phosphit~
was distilled at 168C at 0.2 mm. Hg. to afford a clear colorless liquid. The proton NMR showed aliphatic protons centered at 0.85 and 1.3 ~, the methyl groups of the trimethylphenyl moiety at 2.25 ~, the methine groups adjacent to the oxygen at 4.4 ~, ¦
L0 and the aromatic protons at 6.8 ~.
Structure:

~ ~OfHC6Pl~) EX~MPLE 11 Method of Preparing a New Phosphite:
2,4,6-Trimethylphenyl neopentyl phosphite.

144.8 grams (0.41 mole) of diphenyl-(2,4,6-trimethylphenyl) , phosphite, 42.7 grams (0.41 mole) of dimethyl propanediol and 0.5 ¦

201¦grams of sodium methoxide were heated under a vacuum of 30 mm. Hg.

~¦Phenol was removed from the reaction mixture through a Vigreaux ¦~column at a head temperature of 94C at 30 mm. Hg. The pot tem-perature was increased to 160C ror 3 hours to insure complete removal of phenol. The product, 2,4,6-trimethylphenyl neopentyl 25 ¦ phosphite was distilled at 127 to 130C at 0.35 mm. Hg. to afford ¦

¦¦a clear colorless liquid. The proton NMR showed aliphatic protons ¦

¦~at 0.6 and 1.2~-, the methyl groups of the trimethylphenyl moiety I at 2.2,~, the methylene groups adjacent to the oxygen at 3.4 and j 4.3 &7 and the aromatic protons at 6.8 ~.
30 1 Structure:

--P~X
.
1 _ 12 -,.; , .,_,_ ,. ~ _ . ~ . . , . __ _,.. _, _._ _ , . . . ,, . _ _ . _ . .. _ ___ ~13~6S~

7 Method of Preparing a New Phosphite:
2,4-Di-t-butyle~enyl neopent~l phosphite 150 grams (0.36 mole) of diphen~l-(2,4,-di-t-butylphenyl) phosphite, 37 grams (0.36 mole) of dimethyl propanediol, and 0.5 grams of sodium methoxide were heated under a vacuum of 30 mm. Hg.-Phenol was removed from the reaction mixture through a Vigreaux-column at a head temperature of 94C at 30 mm. Hg. The pot tem-perature was incerased to 160 C for 3 hours to insure complete removal of phenol. The product, 2,4-di-t-butylphenyl neopentyl phosphite was distilled at 110C at 0.1 mm. Hg. to afford a clear colorless liquid which solidified to a white solid upon standing (m.p. 68-73C). The proton NMR showed aliphatic protons from 0.6 to 1.5/5-, the methylene groups adjacent the oxygen at 3.5 and

4.3 ~, and the aromatic protons centered at 7.2 ~_ Structure:

~ \0~

Method_of Preparing a New Phosphite:
2,6-Dimethvlphenvl neo~entvl ~hosnhite .. ... .. .. f .~ ~ , ,, ,~
270 grams (0.8 mole) of diphenyl-(2,6-dimethylphenyl) phosphite, 104.2 grams (1.0 mole) of dimethyl propanediol, and 25 -0.5 grams of sodium methoxide were heated under a vacuum of 30 mm..
Hg. Phenol was removed from the reaction mixture through a Vigreaux column at a head temperature of 94C at 30 mm. ~g. The pot temperature was increased to 160C for 3 hours to insure complete removal of~phenol. The product, 2,6-dimethylphenyl . .

~3~ C~1-2~63 neopentyl phosphite, was distilled at 95C to 115C a-t 0.4 ~m, Hg.
to afford a clear colorless liquid. The proton ~MR showed ali-phatic pro-tons from 0.8 to 1.4 ~J, the methyl groups of the di-methylpheny]. moiety at 2.3 ~, the methylene groups adjacent the oxygen at 3.4 and 4.3 ~, and the aromatic protons at 7.2 ~.
Structure:

' ~\0~

A polycarbonate composition of a homopolymer of 2,2-bis(4-hydroxyphenyl)propane tbisphenol-A) was prepared by reacting essentially equimolar amounts of bisphenol-A and phosgene in an organic medium with triethylamine, sodium hydroxide and phenol under standard conditions and was mixed with the stabilizers shown in Table I plus a trace amount of a commercially obtained blue pigment by tumbling the ingredients in a laboratory tumbler.
This mixture was then fed to an extruder, which extruder was operated at about 500F, and the extruded strands chopped into pellets. The pellets were then injected molded at 600F and 680F
into test samples of about 3 inches by 2 inches by 1/8 inch thick.
Thermal stability to discoloration of the tes~ samples was measured in accordance with ASTM Yellowness Index tYI) Test D1925 on samples molded at 600F and 680F. The results obtained are set forth in TABLE I below.

.. .. . ... .. . . . . . . .. . . . . . ... ..

~3~;S~

TAELE I
Thermal Stability Amount YI of_Tçst Samples Molded At:
Stabilizer(wt%) 600 F 680 F
*A 0.1 3.1 10.1 Example 1 0.04 2.6 5.5 Example 1 0.08 2.6 5.7 Example 2 0.04 2.8 6.1 Example 2 0.08 2.4 5.9 Example 3 0.05 2.9 - 5.7 Example 3 0.10 2.8 6.0 * As disclosed in Ger. Pat. 1,694,285 and referred to in U.S.
Pat. 3,794,629: 1 part octyldiphenyl phosphite 2 parts 3,4-epoxy-cyclohexylmethyl-3,4 ~; epoxycyclohexane carboxylate The test samples molded at 680F were subjected to accelerated heat aging by placing them in an oven at 140C for a period of 1 week and 2 weeks. The results obtained are shown in TABLE II
below.
TABLE II
YI of Heat Aged 680 F
Amount Molded Test SamPles After 20 Stabilizer ~wt%) Initial 1 week 2 weeks A 0.110.1 20.7 28.2 Example 1 0.045.5 14.3 22.3 Example 1 0.085.7 14.0 23.8 Example 2 0.046.1 15.6 23.2 Example 2 0.085.9 14.6 23.6 Example 3 0.055.7 15.8 23.9 Example 3 0.1 6.0 1407 24.4 The results in TABLES I and II above reveal that all of the Example 1, 2 and 3 stabilizers of the invention imparted signifi-cantly better thermal stability than did prior art stabilizer A, even when employed at noticeably lower concentrations.

. , . . ...................... . .... . _, . .. .
~.

~3 A polycarbonate composition was prepared as described in Example 14 and admixed with stabilizers, extruded, and molded into test samples and the YI o the test samples was determined as

5 described in Example 14. The results are shown in Table III below.
TABLE III
THERMAL STABILITY
YI of Test Samples Amount Molded at Stabilizer (Wt. &~ 600F 680F
A 0.1 2.0 6.4 Example 4 0.04 2.1 3.7 Example 4 0.08 1.6 4.7 From the results shown in Table III above, it can be seen-that the Example 4 stabilizer of the invention, even when employed at lower concentrations, imparted comparable or improved thermal stability over prior art stabilizex A, particularly at the higher 680F molding temperature.

A polycarbonate composition was prepared as described in Example 14 and admixed with stabilizers, extruded, and molded into test samples. The YI of the test samples was determined as described in Example 14 and are shown in Table IV below wherein "Control" identifies a polycarbonate composition without stabilize TABLE IV
THERMAL STABILITY
YI of Test Samples Amount Molded at Stabilizer (Wt. %) 600F 680F
Control - 3.3 8.1 A - 0.1 2.0 5.7 ~3~6S~ ~C~-2g~ , TABLE IV (CONT'D.) YI of Test Samples Amount Molded At Stabilizer (Wt. %) 600F 680F
Example 8 0.04 2.0 4.9 " " 0.08 1.8 4.4 Example 9 0.04 1.9 4.7 l " " 0.08 1.8 4.8 ! Example 10 0.04 2.3 4.4 I0 " " 0.08 2.0 4.1 From the results shown in Table IV above, it can be seen that the stabilizers of Examples 8, 9 and 10, although used at lower concentrations, imparted thermal s~ability comparable to ~hat of prior art stabilizer A at the 600F moldiny temperature. However, thermal stability of the invention stabilizers show a marked improvement over stabilizer ~ at the elevated molding temperature !
~ of 680F.
; EXAMPLE 17 A polycarhonate composition was prepared as described in 20 ¦ Example 14 and admixed with stabilizers, extruded and molded into test samples. The YI of the test samples was determined as des-cribed in Example 14 and the results obtained are shown in Table V below wherein "Control" identifies the polycarbonate composition without stabilizer.

Thermal Stab_lity YI of Test Samples Amount Molded At Stabilizer (Wt. ~) 6Q0F 680F
, I
Control - 3.5 6.3 A 0.1 2.1 6.9 *B 0.025 2.2 4.0 *B 0.05 1.8 4.1 ~ 31~S1 8CH-29~3 TABLE V (CONT'D.) YI of Test Samples AmountMolded At Stabilizer (Wt. ~) 600F 680F
_ _ Example 11 0.03 1.9 3.7 ¦¦ Example 11 0.06 1.7 2.9 Example 12 0.035 1.7 3.4 ~ Example 12 0.07 1.6 3.5 I * As disclosed in U.S. Patent 3,509,091: phenyl neopentyl 101 phosphite.

As can be seen from the results in Table V, the stabilizers f Examplesll and 12 exhibit significantly better thermal stability ~than prior art stabilizers A or B at about comparable concentra-tions, particulary at the higher molding temperature of 680F.

The molded test samples of Example 17 were also subjected to , ASTM D-1003 to measure their light transmission before and after they were steam autoclaved at 250F to de~ermine their hydrolytic 1 stability. The results obtained are shown in TABL~ VI below:
TABLE VI
Hydrolytic Stability .% Light Transmission Stabilizer (Wt. %) Example 11 Example 12¦
25 ITime (hrs.) B (0.025) (0.03) (0.035) :, I _ 0 87.6 87.7 87.6 24 47.7 80.8 87.1 1-48 3.2 15.3 84.1 72 - - 63.2 30 1 The results in Table VI above reveal that the hydrolytic ¦ stability of polycarbonate compositions containing the stabilizers ¦
~.,' I . I

, ~3~S3l J

l . ', of E~amples 11 and 12 are significantly superior to prior art stabilizer B which failed before the end of 24 hours, the failure ¦¦level being generally acknowledged when the light transmission l level falls below about 75%.

Following the procedure of Example 14, a polycarbonate composition was prepared, admixed with stabilizers, extruded and then molded into test samples. The YI of the test samples was l determined as described in Example 14 and the results obtained 10¦ are set forth in TABLE VII below:
TABLE VII
Thermal Stab ~

YI of Test Samples Amount Molded At Stabilizer (Wt. ~) 600F 680F
__ I
A 0.1 2.2 7.3 Example 13 0.03 1.8 3.8 Example 13 0.06 1.5 3.2 l From the results in TabLe VII above, it can be seen that the 20 1I stabilizer o~ the invention imparts significantly superior thermal ¦ stability to polycarbonate compositions than prior art stabilizer ¦ A, even at much less concentration levels.
Although the stabilizers of the invention have been parti-l cularly shown employed with high molecular weight aromatic poly-25 ¦carbonates, it should be understood that this has been by way ofillustrating the general efficacy of these stabilizers with thermo-! plastic resins. As will be apparent to the skilled artisan, thestabilizers of the invention can also be employed with other ~thermoplastics such as polyolefins, polyvinyl chloride, polyesters 30 ¦and the like, with substan~ially similar facility and efficacy.
I
l I
:~ - 19 -~ ... ___.... ..... _ ._ . i

Claims (30)

The embodiments of the invention in which an exclu-sive property or privilege is claimed are defined as follows:

1. A phosphite compound represented by the general struc-ture:

wherein R1 can independently be an alkyl of about C1-C30; an aryl of about C6-C30, and alkyls of C2-C20 which can form mono-cyclic structures; and, A is a hindered phenol represented by the general structure:

wherein. R2, R3 and R4 can be the same or different and each can independently be hydrogen, halogen or C1-C4 alkyl provided that neither R2 and/or R4 are hydrogen.

2. The phosphite compound of claim 1 wherein said aryl is one having about C6-C12.

3. A phosphite compound having the structure:

4. A phosphite compound having the structure:

5. A phosphite compound having the structure:

6. A phosphite compound havinq the structure:

7. A phosphite compound having the structure:

8. A phosphite compound having the structure:

9. A phosphite compound having the structure:

10. A phosphite compound having the structure:

11. A phosphite compound having the structure:

12. A phosphite compound having the structure:

,

13. A phosphite compound having the structure:

,

14. A phosphite compound having the structure:

15. A phosphite compound having the structure:

16. A thermally and hydrolytically stabilized thermoplastic composition comprising an admixture of a thermoplastic resin and a stabilizing amount of a phosphite compound represented by the general structure:

wherein R1 can independently be an alkyl of about C1-C30, an aryl of about C6-C30, and alkyls of C2-C20 which can form monocyclic struc-tures; and, A is a hindered phenol represented by the general structure:

wherein R2, R3 and R4 can be the same or different and each can independently be hydrogen, halogen or C1-C4 alkyl provided that neither R2 and/or R4 are hydrogen.

17. The composition of claim 16 wherein said aryl is one having about C6-C12.

18. The composition of claim 16 wherein said phosphite com-pound is a member selected from the group having the following structures:

(a) ;

(b) ;

(c) ;

(d) ;

(e) ;

(f) ;

(g) ;

(h) ;

(i) ;

(j) ;

(k) ;

(l) ;

(m) ; and mixtures thereof.

19. The composition of claim 16 wherein said stabilizer is present in an amount of about 0.005-1.0 percent by weight of said thermoplastic resin.

20. The composition of claim 19 wherein said stabilizer is present in an amount of about 0.01-0.50 weight percent.

21. The composition of claim 16 wherein said thermoplastic resin is a member of the group consisting of aromatic polycar-bonates, polyolefins, polyvinyl chloride and polyesters.

22. The composition of claim 21 wherein said thermoplastic resin is a high molecular weight aromatic polycarbonate.

23. A thermally and hydrolytically stabilized aromatic polycarbonate composition comprising an admixture of a high molecular weight aromatic polycarbonate and a stabilizing amount of a phosphite compound represented by the general structure:

wherein R1 can independently be an alkyl of about C1-C30, an aryl of about C6-C30, and alkyls of C2-C20 which can form monocyclic struc-tures; and, A is a hindered phenol represented by the general structure:

wherein R2, R3 and R4 can be the same or different and each can independently be hydrogen, halogen or C1-C4 alkyl provided that neither R2 and/or R4 are hydrogen.

24. The composition of claim 23 wherein said aryl is one having about C6-C12.

25. The composition of claim 23 wherein said phosphite com-pound is a member selected from the group having the following structures:

Claim 25 (contd) (a) ;

(b) ;

;
(c) (d) ;

(e) ;

(f) ;

(g) ;

;
(h) (i) ;

(j) ;

(k) ;

(l) ;

(m) ; and mixtures thereof.

26. The composition of claim 23 wherein said stabilizer is present in an amount of about 0.005-1.0 percent by weight of said aromatic polycarbonate.

27. The composition of claim 26 wherein said stabilizer is present in an amount of about 0.01-0.50 weight percent.

28. The composition of claim 23 wherein said aromatic polycarbonate is derived from 2,2-bis(4-hydroxyphenyl)propane.

29. The composition of claim 16 which includes a stabilizing amount of an epoxide co-stabilizer.

30. The composition of claim 23 which includes a stabilizing amount of an epoxide co-stabilizer.