CA1116331A

CA1116331A - Plasticized polycarbonate composition

Info

Publication number: CA1116331A
Application number: CA000306526A
Authority: CA
Inventors: Victor Mark; Phillip S. Wilson
Original assignee: General Electric Co
Current assignee: General Electric Co
Priority date: 1978-06-29
Filing date: 1978-06-29
Publication date: 1982-01-12

Abstract

ABSTRACT OF THE DISCLOSURE
A plasticized polycarbonate composition comprising in admixture a high molecular weight aromatic carbonate polymer and a minor amount of certain oligo-polymeric siloxane plasticizers. The plasticized polycarbonates of the present invention are particularly suitable for use in melt fabricated articles.

Description

~ CH-2554 This invention is directed to a plasticized polycarbonate composition comprising in admixture a high molecular weight aromatic carbonate polymer and a minor amount of an oligo-polymeric siloxane plasticizer.
Polycarbonate polymers are excellent molding materials as products made therefrom have high impact strength, toughness, high transparency, wide temperature limits (high impact resistance below -60C and a UL thermal endurance rating of 1150C with impact), good dimensional stability, high creep resistance and electrical properties which qualify it as sole support for current carrying parts.
Polycarbonates are, however, very difficult to fabricate from melts for the reason that melts thereof have exception-ally high viscosities. Attempts to overcome this difficulty by the incorporation with the polycarbonate of materials known to reduce the viscosity of other resins have very generally been unsuccessful. Many standard viscosity control agents appear to have little or no effect on the viscosity of polycarbonate. Other compounds known to lower the viscosity of resins cause degradation of polycarbonate resins. Some compounds, conventionally employed to im-provie the workability of polymers, produce an embrittling effect on polycarbonates when they are mixed therewith and the resin is subjected to elevated temperatures as in molding.
Still other materials, while satisfactory stiffness modify-ing agents for other plastics, are too volatile to be in-corporated agents for other plastics, are too volatile to be incorporated with polycarbonates since polycarbonates have much higher melting points than many other thermo-plastics.
It has been surprisingly discovered that, by admixing a minor amount of an oligo-polymeric siloxane plasticizer with a high molecular weight aromatic carbonate polymer, the resultant polycarbonate composition has reduced melt viscosity and does not become brittle or degraded upon molding and thus retains its characteristic high impact strength.
In the practiee of this invention, the oligo-polymerie siloxane plasticizers are characterized by the following formulae:

~ ~ ~ CH ~ +

(b) ~ 5 - 0 - ~ CH ~ ~ -20 (c) ' ~ ~
C,H3 --si - o _ CH2 - COOCH3 i . 35 (d) L ~ o ~

(e) - ,CH3 , 3 _ - Si 0 - CH - C - CH - 0 -, ~CH-2594 ~f) CH3 --si - o _ ,CH2 (g) CH3 --si - o C=O
NH

These oligo-polymeric siloxane plasticizers are prepared by well known methods in the art such as from the corresponding dichloro silicone precursor with the dihydroxy compound in the presence of bases.
The amount of oligo-polymeric siloxane plasticizer employed in the prackice of thîs invention may vary from 0.05 to about 5.0 parts per hundred parts of aromatic carbonate polymer.
Preferably, these organic plasticizers are employed in amounts of from 0.25 to 2.0 parts per hundred parts of aromatic carbonate polymer.
In the practice of this invention, the high molecular weight aromatic polycarbonates that can be employed herein are homopolymers and copolymers and mixtures thereof which have an I.V. of 0.40 to 1.0 dl./g. as measured in methylene chloride at 25C that are prepared by reacting a dihydric phenol with a carbonate precursor. Typical of some of the dihydric phenols that may be employed in the practice of this invention are bisphenol-A (2,2-bis(4-hydroxyphenyl)-propane), bis(4-hydroxyphenyl)methane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 4,4-bis(4-hydroxyphenyl)heptane,

2,2-(3,5,3',5'-tetrachloro-4,4'-dihydroxydiphenyl)propane, (3,3'-dichloro-4,4'-dihydroxydiphenyl)methane. Other dihydric phenols of the bisphenol type are also available and are dis-

- 3 -,. ..

~ 8CH-2594 , , .

closed in U.S. Patents 2,999,835 dated September 12, 1961 3,028,365 dated April 3, 1962 and U.S. patent No 3,334,154 dated August 1, 1967.
It is, oE course, possible to employ two or more dif-ferent dihydric phenols or a copolymer of a dihydric phenol with a ylycol or with hydroxy or acid terminated polyester, or with a dibasic acid in the event a carbonate copolymer or inter-polymer rather than a homopolymer is desired for use in the preparation of the aromatic carbonate polymers of this invention. Also employed in the practice of this invention may be blends of any of the abo~e materials to provide the aromatic carbonate polymer.
The carbonate precursor may be either a carbonyl halide, a carbonate ester or a haloformate. The carbonyl halides which can be employed herein are carbonyl bromide, carbonyl chloride and mixtures thereof. Typical of the carbonate esters which may be employed herein are diphenyl carbonate, di-(halophenyl) carbonates such as di-(chloro-phenyl) carbonate, di-(bromophenyl) carbonate, di-(trich-lorophenyl) carbonate, di-(tribromophenyl) carbonate, etc., di-(alkylphenyl) carbonates such as di(tolyl) carbonate, etc., di-(naphthyl) carbonate, di-(chloronaphthyl) car-bonate, phenyl tolyl carbonate, chlorophenyl chlorona-phthyl carbonate, etc., or mixtures thereof. The halofor-mates suitable for use her~in include bis-haloformates of dihydric phenols (bischloroformates of hydroquinone, etc.) or glycols (bishaloformates of ethylene glycol, neopentyl glycol, polyphenylene glycol, polyethtlene glycol, etc.).
While other carbonate 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 dihy-

4 --- ~3~ 8C~1-2594 dric phenol, a dicarboxylic acid and carbonic acid. These are disclosed in U.S. Pat 3,169,131 dated Feb/9/1965.
These aromatic carbonate polymers of this invention may be prepared by employing a molecular weight regulator, an acid acceptor and a catalyst. The molecular weight regulators which can be employed in carrying out the process of this invention in-clude monohydric phenols such as phenol, chroman-I, paraterti-arybutylphenol, parabromophenol, primary and secondary amines, etc. Preferably, phenol is employed as the molecular weight regulator.
A suitable acid acceptor may be either an organic or an inorganic acid acceptor. A suitable organic acid acceptor is a tertiary amine and includes such materials as pyridine, triethylamine, dimethylaniline, tributylamine, et. The inorganic acid acceptor may be one which can be either a hydroxide, a carbonate, a bicarbonate, or a phosphate of an alkali or alkaline earth metal.
The catalysts which are employed herein can be any of the suitable catalysts that aid the polymerization of bisphenol-A
with phosgene. Suitable catalysts include tertiary amines such as, for example, triethylamine, tripropylamine, N,N-dimethyl-aniline, quaternary ammonium compounds such as, for example, tetraethylammonium bromide, cetyl triethyl ammonium bromide, tetra-n-heptylammonium iodie, tetra-n-propyl ammonium bromide, tetramethylammonium chloride, tetramethyl ammonium hydroxide, tetra-n-butyl ammonium iodide, benzyltrimethyl ammonium chloride and quaternary phosphonium compounds such as, for example, n-butyltriphenyl phosphonium bromide and methyl-triphenyl 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 ran-domly branched polycarbonate.

33~

These polyfunctional aromatic compounds contain at least three functional groups which are carboxyl, carboxylic anhydride, haloformyl or mixtures thereof. Examples of these polyfunctional aromatic compounds which may be employed in the practice of this invention include: trimellitic anhy-dride, trimellitic acid, trimellityl trichloride, 4-chloro-formyl phthalic anhydride, pyromellitic acid, pyromellitic dianhydride, mellitic acid, mellitic anhydride, trimesic acid, benzophenonetetracarboxylic acid, benzophenonetet-racarboxylic anhydride and the like. The preferred poly-functional aromatic compounds are trimellitic anhydride or trimellitic acid or their haloformyl derivatives.
Also, included herein are blends of a linear poly-carbonate and a branched polycarbonate.
The composition of the instant invention is prepared by blending the high molecular weight aromatîc poly-carbonate with the additive by conventional methods.
Obviously, other materials can also be employed with the aromatic carbonate polymer of this invention and include such materials as anti-static agents, pigments, thermal stabilizers, ultraviolet stabilizers, reinforcing fillers and the like.
In order to more full and clearly illustrate the present invention, the following specific examples are presented. It is intended that the examples be considered as illustrative rather than limiting the invention dis-closed and claimed herein. In the examples, all parts and percentages are on a weight basis unless otherwise specified.
One hundred (100) parts of an aromatic polycarbonate, prepared from 2,2-bis(~-hydroxyphenyl) propane and phosgene in the presence of an acid acceptor and a molecular weight regulator and having an intrinsic viscosity of about 0.57, ~ 33~ 8CH-2594 is mixed with the additive listed in the Table by tumbling the ingredients together in a laboratory tumbler. The re~ulting mixture is then fed to an extruder which is operated at about 265 C, and the extrudate is comminuted into pellets.
The pellets are then fed into a plastomer and the flow rate of the polymer is measured according to ASTM D1238-70, condition 0. The melt flow rate is set forth in the Table, Additionally, the pellets are injection molded at about 315C into test specimens of about 5 by 1/2 by 1/8 inch thiCk. The impact strength of these specimens is then measured according to the Izod test, ASTM D-256. The impact strength is set forth in the Table. The sample labeled CONTROL is the polycarbonate as prepared without additive.

~L6331 8CH 2 5 9 ~: _ ~: H
~ o u~
J~ U7 U~ ~ U~

(;) h H

,_ 3o . o ~ aJ ,~ ~ o h ~ O
~1 ~ ~ O 1--l ~ ~ N
al h ~ ~ .

h .~ ~C
U~ o r) o ~ a) 4~ I I o ~ o ,1 O ~

h ~ ~
~ ~:- ~ I

O ~

5: X
~3 ~ o o ~ ~o s ~ ~ ;3~3~3L 8CH 25g4 a~
u~
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U~
~r O ~D ~r In ,1 ,1 ,1 E
H

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,~ a) o ,~ ~ r~
a~
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.~ 5:

4~ o o o O U~
.
E P~
_ lo , - ! I o ,~ 1, - ..
V ~ X

X 'U, ~ ~ 'U, ~ ~ . ~-- V--V--V

.633~ 8CH 2594 G
a) H
h u~ u~
Q
r I~ . ,~

H

O O
~ ~1~
,_1 1~; h ~ I , _ a a~
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_ n r~

.~ O ~ L~

C~ O
,~ O l ~
I t~ I O OD
~: ~ u--Z C,) ~3CH-~594 It can be seen from the data in the Table that when the instant oligo-polymeric siloxane plasticizer is added to a high molecular weight aromatic polycarbonate, the re-sulting polycarbonate composition has reduced melt viscosity as shown by the higher melt flow rate while retaining impact strength.
It will thus be seen that the objects set forth above among those made apparent from the preceding description are ef-ficiently attained and since certain changes may be made in carrying out the above process and in the composition set forth without departing from the scope of this invention, it is intended that all matters contained in the above description shall be interpreted as illustrative and not in a limiting sense.

~_

Claims

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

1. A plasticized polycarbonate composition comprising in admixture a high molecular weight aromatic carbonate polymer and a minor amount of an oligo-polymeric siloxane selected from the group having the following formulae:
(a) (b) ( C ) (d) (e) (f) (g) .

2. The composition of claim 1 wherein the plasticizer is present in an amount of from 0.05 to about 5.0 parts per hundred parts of aromatic carbonate polymer.

3. The composition of claim 1 wherein the aromatic carbonate polymer is derived from bisphenol-A.

4. The composition of claim 1 wherein the aromatic carbonate polymer is a copolymer derived from bisphenol-A
and tetrabromo bisphenol-A.