CA1188029A - Polycarbonate resin impact modified with polyolefins and containing paraffin derivatives - Google Patents

Abstract

ABSTRACT
A polycarbonate composition having improved melt flow and improved impact strength after aging at elevated temperatures, comprising polycarbonate resin with poly-olefins and a paraffin derivative. A preferred composition comprises, in admixture, a high molecular weight aromatic carbonate polymer and a minor amount of a polyolefin and pentaerythritol tetrastearate.

Description

~8~

-1- 8C~ 29~8 POLYCARBON~TE RESIN IMP~CT MODIFIED WITH POLYEOLFINS
AND CONTAINING PARAFFIN DERIVATIVES
This invention r~lates to polycarbonate compositions and more particularly to modified polycarbonate compositions having additives to improve the melt flow and impact strength after aging at elavated temperatures.
BACKGROUND OF THE iNv~ ON
Polycarbonate polymers are excellent molding materials because products made therefrom have high impact strength, toughness, high transparency, wide temperature limits (high impact resistance below -60 C. and a UL thermal enduranc~ rating of 115 C. with i~pact), good dimen.sional stability, high creep resistance and electrical properties which qualify it as sole support Eor current carrying parts.
Polycarbonates are, however, very difficult to fabricate from melts for the reason that melts thereof have exceptionally high viscosities. Attempts to overcome this difficulty by the incorporation with the polyc~rh~n~te of materials known to reduce the viscosity of other resins have generally been unsuccessful. Many conventional viscosity control agents appear to have little or no effect on the viscosity of polycArh~nAte. Other compounds known to lower the viscosity of resins cause degradation of polycarbonate resin. Some compounds, conventionally employed to improve the workAhil;ty of polymers, produce an embrittling effect on polycarbonates when they are mixed therewith the resin is subjected to elevated temperatures as in molding. Still other materials, while satisfactory stiffness modifying agents for other plastics, are too volatile to be incorporated with polycarbonates since polycarbonates have much higher melting points than many other thermoplastics.

8C~-2948

2--B ~ ~ Another difficulty with polycarbonates is that are subject to loss of their high impact strength upon aging at elevated temperatures. Attempts to overcome this difficulty by incorporation with the polycarbonate of 5 impact modifiers such as polyolefins have been to some extent successful. ~owever, these impact modified compositions will also undergo embrittlement if subjected to elevated temperatures for a sufficient period of time since these impact modifiers tend to only prolong the period of time 10 until the embrittlement occurs.
SU~RY OF THE :INVENT:ION
In accordance with the present invention there is herein disclosed a polycarbonate composition comprising 15 in admixture, a high molecular weight aromatic carbonate polymer and a minor amount o~ a polyolefin and a paraffin of the following formula:
Cn 2n~1 wherein n has a value of from about 8 to ~bout~ 60~, and which is characterized by a straight or br~chc~ carbon chain and R is H or an organic radical which is reactive with polycarbonate.
It has been discovered that, by a~m;~;ng a amount of a polyolefin or polyolefins with a paraffin 25 derivative or paraffin derivatives with a high molecular weight aromatic carbonate polymerl the resultant polycar-bonate composition has reduced melt viscosity and less tendency to embrittle upon molding or upon aging at ele-vated temperatures than compositions con~aining either the 30 impact modifying agent (the polyolefin) or the flow enhansing agent (the paraffin derivative~ above, and thus retains its characteristic high impact strength.

,

-3- Docket 8C~1~2948 Use of the term "paraffin deriva-tives" through-out this application is intended to mean, and should,be understood as meaning the class of aliphatic hydrocarbons characterized by a straight or branched carbon chain re-presented by the general formula:
n 2n+lRwhich are commonly employed in the art as lubricating agents.
The paraffin derivatives of the instant invention are well known in the art and are prepared by well known methods.

DETAILED DE~CRIPTION OF THE INVENTION
In the practice of the invention, a paraffin derivative is incorporated wlth a polyolefin into an aro-matic polycarbonate composition. Polyolefins act as im~
pact modifiers in polycarbonate compositions increasing -the impact strength of the same. Suitable polyolefins for use in the present invention include, for example, poly-ethylene, polypropylene, polyisobutylene, ethylene propy-lene diene copolymer, and their oxides, copolymers and terpolymers thereof. Other polyolefins suitable for use herein will be apparent to those skilled in the art. The preferred polyolefins are polyethylene and polypropylene.
These polyolefins and their oxides, copolymers and ter-polymers are available commercially.
The amount of the polyolefin present in the com-position of the present invention can range from about 2.0 parts to about 8.0 parts, by ~eight, per hundred parts of the aromatic polycarbonate. Preferably, the polyolefin is ,present in amounts of from about 3.5 parts to about 4.5 parts, by ~eight, per hundred parts of the aromatic poly-carbonate. In the practice of the present invention theuseful paraffin derivatives include those having carbon chain lengths ranging from about 8 carbon atoms to about

-4- Docket 8CH-2948 60 carbon atoms. The para~fin c:an have organic functional groups a~tached to the carbon chains or can be free o~
organlc ~unctional groups. The functional organic groups which can be bonded to the carbon chain of the paraffins include those or~anic groups which are unreactive with the polycarbonate resin employed, such as carboxylate esters, carbonate es~ers, ethers, aryls and vinylsO
The amount of paraffin derivatives employed in the practice of this invention may vary from about .10 to about 1.0 parts per hundred parts of aromatic carbonate polymer. Preferably, these paraffins are employed in amounts of from about .60 to about .~0 parts per hundred parts of aromatic carbonate polymer.
In the practice of this invention, the high molecular weight aromatic polycarbonates which can be employed herein, are homopolymers and copolymers and mixtures thereof which ha~e an intrinsic viscosity of 0.40 to 1.0 dl./g. as measured in methylene chloride at 25C.
The aromatic polycarbonates are generally p epared by re-acting a dihydric phenol with a carbonate pxecursor.
Typical of some of the dihydric phenols which can be employed in the practice of thi$ invention, are bisphenols, such as bis(4-hydroxyphenyl) methane, 2,2-bis(4-hydroxy-phenyl) propane (hereinafter referxed to as bisphenol-A), 2,2-bis(4-hydroxy-3-~ethylphenyl) propane, 4,4-bis(4-hydroxy-phenyl) heptane, 2,2-bis(4-hydroxy-3,5-dichlorophenyl) propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl) propane, and the like; dihydric phenol ethers such as bis(4-hydroxy-phenyl) ether, bis(3,5-dichloro-4-hydroxyphenyl) ether, and the like; dihydroxydiphenyls such as p,p'-dihydroxydiphenyl, 3,3'dichloro-4,4'-dihydroxydiphenyl, and the like; dihydro-xyaryl sul~ones such as bis(4-hydroxyphenyl) sul~one, bis~3,5-dimethyl-4-hydroxyphenyl) sulfone, and the like;
dihydroxy benzenes, resorcinol, hydroquinone/ halo- and alkyl-substituted dihydroxy ~enzenes such as

-5- Docket 8CH-2948 l,4-dihydroxy-2,5-dichlorobenzene, l,4-dihydroxy-3~methyl-benzene and the like; and dihydroxy diphenyl sulfoxides such as bis(4-hydroxyphenyl) sulfoxide, bis-(3,5-dibromo-4-hydroxyphenyl) sulfoxide, and the like. A variety of addi-tional dihydric phenols are also available to providecarbonate polymers and are disclosed in U.S. Patent Nos.
2,998,835; 3,028,365 and 3,153,008. Also suitable for preparing the aromatic carbonate polymers are copolymers prepared from any of the above 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-phenyl~ propane, and the like.
It is,of course, possible to employ two or more different dihydric phenols or a copclymer of a dihydric phenol with glycol or with hydroxy or acid-terminated polyester, or with a dibasic acid in the event a carbonate copolymer or interpolymer rather than a homopolymer is de-sired for use in the preparation of the aromatic carbonate polymers of this invention. ~lso employed in the practice of this invention may be blends of any of the above 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 ca~bonyl bromide, carbonyl chloride and mixtures thexeof. 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-(tri-chlorophenyl) carbonate, di-(tribromophenyl) carbonate, etc., di-(alkylphenyl) carbonate such as di-(tolyl) car-bonate/ etc., di-(naphthyl) carbonate, di-(chloronaphthyl~
car~onate, phenyl tolyl carbonate, chlorophenyl chloro-naphthyl carbonate, etc., or mixtures thereof. The halo-formates suitable for use herein inclllde bis-haloformates of dihydric phenols (bischloroformates of hydroquinone, 2~
~ -6~ Docket 8CH-2948 etc.) or glycols (bishaloformates of ethylene glycol, neopentyl glycol, polyethylene glycol, etc.). While other carbonate precursors will occur to those skilled in the art, carbonyl chloride, also known as phosgene, is preferred.
The polycarbonates can also be made from a di-hydric phenol, a dicarboxylic acid and carbonic acid.
These are disclosed in U.S. Patent 3,169,121 i~sued -February 9, 1965.
The aromatic carbonate polymers of this invention are pre~ërably prepared by employing a molecular ~eight re-gulator; an aGid acceptor and a catalyst. The molecular weight regulators which may be employed in carrying out the process of this invention, include phenol, cyclohexanol, methanol, para-tertiarybutylphenol, parabromophenol, etc.
Preferably, phenol is employed a~ the molecular weight re-gulator.
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, etc. The inorganic acid acceptor may be one which can be either a hydroxide, a carbonate, a bicarbonate, or a phos-phate of an alkali or alkali earth metal.
2S 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, ~or example, triethylamine, tri-propylamine, N,N-dimethylaniline, quaternary ammonium compounds such as, for example, tetraethylammonium bromide, cetyl triethyl ammonium bromide, tetra-n-heptylammonium iodide, tetra-n-propyl ammonium bromide, tetramethylammonium chloride, tetramethyl arnmonium hydroxide, tetra-n-butyl ammonium iodide, ben2yltrimethyl ammonium chloride and quaternary phsophonium compounds such as, for example, -7- Docke-t 8CH-2948 n-butyltriphenyl phosphonium bromide and methyltriphenyl 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 yroups which are carboxyl, car-boxylic anhydride, haloformyl or mixtures thereof. Examples of these polyfunctional aromatic compounds which may be employed in the practice of this invention, include: tri-mellitic anhydride, trimellitic acid, trimellityl trichloro-ide, 4-chloroformyl phthalic anhydride, pyromellitic acid, pyromellitic dianhydride, mellitic acid, mellitic anhydride, trimesic acid, benzophenonetetracarboxylic acid, benzo-phenonetetracarboxylic anhydride and the like. The pre-ferred polyfunctional aromatic compounds are trimellitic anhydride or trimellitic acids or their acid chloride derivatives.
Also included herein are blends of a linear poly-carbonate and a branched polycarbonate.
The composition of the instant invention may be prepared by blending the high molecular weight aromatic polycarbonate with the paraffin derivative and the poly-olefin impact modifier by conventional methods. A plural-ity o polycarbonates, parafflns and polyolefins ~ay also be blended~
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 ~illers and the like.

~ -8~ ~ Docket 8CH-~948 PREFERRED EMBODI~E~TS OF THE INVENTION
In order to more fully and clearly illustrate the present invention, the following specific examples are presented. It is in-tended that the examples be considered as illustrative rather than limiting the invention dis-closed and claimed herein. In the examples, all parts andpercentages are on a weight basis unless otherwise speci-fied.
Example 1 ~ A polycarbonate composition was prepared by re-acting essentially cquimolar amounts of 2,2-bis(4-hydroxy-phenyl~ propane (referred to as bisphenol-A) and phosgene in an organic medium with triethylamine, aqueous sodium hydroxide and phenol. One hundred parts of the polycar-bonate composition was then mixed with 4.2 parts of a high density polyethylene manufactured by the U.S. Industrial Chemicals Co. under the commercial designation LB742 and 0.75 parts of a paraffin derivative as set forth in Table 1. The resulting mixture was then fed into an extruder which was operated at between about 277C~ to about 293C., and the extrudate was comminuted into pellets.
The melt flow rates were determined and are set forth in Table 1.
Additionally, the pellets were injection molded at about 299C. into test bars of about 2-1/2 in. by 1/2 in. by about 1/8 in. thick. The impact strength of these bars were measured according to the Notched Izod test, ASTM D-256. The impact strength is set forth in Table 1, The sample labelled CONTROL is the polycarbonate as pre-pared without the polyethylene or the paraffin derivative.

-9- Docket 8CH-2948 Table 1 I~ACT STRENGTH
~LT(ft.lb/in.) ADDI~IVES FLOW1/8 inch N~tcled I~od Impact Modifier Paraffin RATE ~ged 4 Aged 24 5(4.2 parts p~r (0.75 partsgr./ As Hrs.at Hrs.at hundred) per hur~dred) 10 min.Molded 125 C. 125 C.
Control Control 15.1 14.7 1.5 - Pentaerythritol tetrastearate16.9 15.3 1.2 10Polyethylene - 14.9 13.3 11.3 3.6 Polyethylene Pentaerythri~l tetrastearate16.9 12.7 11.7 9.5 Polyethylen~ di(nonylphenyl) carbonate 15~9 12.7 lO.0 7.3 15Polyethylene Paraffin Wax17.8 12~7 10.3 7.0 The combination of the three ingredients listed above in orde:r of increasing aged impact streng~h are poly-carbonate and ~a~ara$fin derivative, polycarbonate alone, polycarbonate and polyethylene, then polycarbonate and polyethylene and a paraffin derivative, It can be seen from the data in Table 1 that when a paraffin derivative and a polyethylene impact modifier are both incorporated into a high molecular weight aromatic poly-carbonate an improvement in flow rate of the resultant resin is achieved accompanied by a mar~ed improvement in impact strength after aging at an elevated temperature. The use of either theparaffin additive or the impac-t modifier separately would not provide such a desirable result.
Example 2 A polycarbonate ccmposition was prepared as in Example 1. One hundred parts of the polycarbonate composi-tion was then mixed with 4.2 parts of the polyethylene -10~ Docket ~CH~2948 mentioned in Example 1 and various amounts of pentaery thritol tetras-tearate as set forth in Table 2. The re-sulting mixtures were then fed into an extruder which was opexated at about 260~C. and the extrudate was comminuted S in-to pellets.
The melt flow rates of the resulting polymers were measured as in Example 1. The melt flow rates are set forth in Table 2.
The pellets were molded into test bars, and the impact strength of the resultant polymers were determined as in Example 1. The impact stren~th is set forth in Table 2. The sample labelled CONTROL is the polycarbonate as prepared with 4.2 parts per hundred of polyethyleneO
Table 2 I~rACT STRENGTH
ADDITIVE ~LT (_t.lb/in.) Pentaerythritol FLOW ]/ inch Notch d Izod Tetrastearate RATE As Aged 4 Hrs Aged 24 Hrs.
(Parts per hundred) gr./10 min. Molded At 125 C~ At 125 C.
C~ntrol 14.5 12.4 3.3 2.6 0~25 15.9 12.7 5.5 2.6 0.50 16.9 1~.7 5.3 2.7 0.75 17.3 12.7 6.5 2.6 1.25 18.4 12.0 3.9 2,6 It can be seen from the data in Table 2 that optimum results can be obtained by employing the paraffin additive in amounts of about 0.75 parts per hundred based on the weight of the entixe polymer composition. Overall, the samples in Table 2 did not perform as well in the aged Notched Izod testing as those in Table 1. This discre-panoy is possibly due to the difference in extrusion temperature in preparing the two sets of samples.

2~
Docket 8CH 2948 E~ample 3 , - A polycarbonate composition was prepared as in Example l. One hundred parts of the polycarbonate com-position was ~hen mixed with 0.75 parts of a paraffin, pentaerythritol tetrastearate, and various amounts of a poly~hylené, described in Example l, as set forth in Table 3. The resulting mixtures were then fed into an extruder which was operated at from about 277C. to about 293C., and the extrudate was comminuted into pellets.
The melt flow rate of the resultant polymers were measured as in Example l. The melt rlow rate is set forth in Table 3.
The pellets were molded into test bars, and the impact stren~th of the resultant polymers were determined as in Example l. The impact strength is set forth in Table 3.
Table 3 ~ CT STRENGTH
MELT (ft.lb./in.) Impact Modifier FL0l~ 1/8 i~. Notched Izod 20Polyethylene RhTE As Aged 4 Hrs. Aged 24 Hrs.
(parts prr hundred) gr/10 ~in. ~lolded At 125~ C. At 125 C.
2.1 15.1 13.3 2.0 2.0 4.2 16.9 12.7 ~.0 2.3

6.3 16.0 10.7 7.3 5.2 It can be seen from the data in Table 3 that optimum results were obtained by employing the polyolefin impact modifier in amounts of about 6.3 parts per hundred based on the weight of the entire polymer composition.
Overall, the samples in Table 3 did not perform as well in the aged Notched Iz~d testing as those in Table l.
This discrepancy is possibly due to the difference in ex-trusion temperature in preparing the two sets of samples.

~ ~88~9 ~
-12- ~ Docket ~CH~948 Example 4 A polycarbonate composition was prepared in Example 1 containing 0.1% of a phosphite color stabilizer.
One hundred parts of the polycarbonate was mixed with 4.2 parts of a polyolefin as set forth in Table 4 and 0.75 parts of a paraffin derivative also set forth in Table 4.
The polyolefins employed were a high density polyethylene designated 3747 DMD~ manufactured by Union Carbide, a low density polyethylene designated 102 NA manufactured by Rexene and a polyethylene polypropylene copolymer desig-nated X0398 or 18-S2 manufactured by Rexene.
The resulting mixtures were -then fed into an extruder which was operated at from about 277C. to about 293C., a-nd the extr~date was comminuted into pellets.
The melt flow rate of the resultant polymers were measured as in Example 1. The melt flow rate is set forth in Table 4.
The pellets were molcled into test bars, and the impact strength of the resultant polymers were determined as in Example 1. The impact strength is set forth in T~bl~

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

-13~ Docke-t 8CH-2948 I~PACT STRENGTH
ADDITIVES ~ELT ( t. lb/in.) I~p~ct ~lodifier Paraffin FLO~ 1/ in. Notched Izod (4.2 parts per (0.75 ~arts R~TE As Aged 4 Hrs.
hundred? per huLIdr~d) g~./10 min. ~lol~ed At 125 C.
Polye~hylene l~3474 D~J - 12.8 12.0 3.7 Polyethylene ~oetdecyl ~3474 D~J vinyl ethe~ 17.412.0 4.6 Polyethylene Stearoyl #3~!74 D~J stearate, 15.6 12.6~66.2 Polyethylene Rexene 102NA - 13.713~3~ 2.7 Polyethylene Oct~ecyl Rexene 102NR vinyl ether 18.9 12.0 3.5 Polyethylene Ste~royl Rexene 102~A stearate 17.0 12.0 8.0 Polyethylene-polypropylene Rexene 0398 - 15.1 13.3;33.5 Polyethylene- Octadecyl polypropylene vinyl ether Rexene 0398 16.9 12.6~ 6.8 Polyethyle~e- Stea-~oyl polypr~pylene stearate Rexene 0398 17.9 12.8 10.1 It will thus be seen that the objects set forth above, among those made apparent from the preceding des-cription are efficiently attained, and since certain changes may be made i~ carrying out the above process and in the composition set forth wi-thout departing from the scope of this invention, it is in-tended that all matters in the above descxiption shall be interpreted as illustra-tive and not in a limiting sense.

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Claims (9)

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

1. A polycarbonate composition comprising in admixture, a high molecular weight aromatic carbonate polymer and a minor amount of a polyolefin and a paraffin derivative of the following formula:
CnH2n+1R
wherein n has a value of from about 8 to about 60, and which is characterized by a straight or branched carbon chain and R is H or an organic radical which is unreactive with polycarbonate, said polyolefin and paraffin derivative in quantities which reduce the melt viscosity and provide better impact resistance after aging at elevated temperature than either the polyolefin or paraffin derivative alone.

2. The composition of claim 1, wherein the paraffin derivative contains a functional organic group selected from the group consisting of carboxylate esters, carbonate esters, ethers, aryls and vinyls and aromatic carbonate polymer is derived from bisphenol-A.

3. The composition of claim 1 or 2, wherein the paraffin derivative is pentaerythritol tetrastearate.

4. The composition of claim 1, wherein the polyolefin is selected from the group consisting of polyethylene, polypropylene, polyisobutylene, ethylene ? diene copolymer, copolymers and terpolymers thereof.

5. The composition of claim 1, comprising from about .10 to 1.5 parts of a paraffin derivative per hundred parts of aromatic carbonate polymer.

6. The composition of claim 1, comprising from about .60 to about .80 parts of a paraffin derivative per hundred parts of aromatic carbonate polymer.

7. The composition of claim 1, comprising from about 2.0 parts to about 8.0 parts polyolefin per hundred parts of aromatic carbonate polymer.

8. The composition of claim 1, comprising from about 3.5 parts to about 4.5 parts polyolefin per hundred parts of aromatic carbonate polymer.

9. The composition of claim 5 comprising about 3.5 to about 4.5 parts polyolefin per hundred parts of aromatic carbonate polymer.