WO2014168869A1

WO2014168869A1 - Flame retarded polycarbonate composition, process for making the same and article containing the same

Info

Publication number: WO2014168869A1
Application number: PCT/US2014/033159
Authority: WO
Inventors: Sergei V. Levchik; Gerald R. Alessio; Rachel Shtekler; Eyal EDEN; Pierre Georlette
Original assignee: Icl-Ip America Inc.
Priority date: 2013-04-10
Filing date: 2014-04-07
Publication date: 2014-10-16

Abstract

There is provided herein a flame retarded polycarbonate composition comprising: (a) at least one aromatic polycarbonate or polycarbonate based alloy; and, (b) at least one metal phosphonate. There is also provided a molded part(s) or article(s) containing the flame retarded polycarbonate composition, e.g., a flame retarded electric, electronic, or automotive component containing the flame retarded polycarbonate composition.

Description

FLAME RETARDED POLYCARBONATE COMPOSITION, PROCESS FOR MAKING THE SAME AND ARTICLE CONTAINING THE SAME

FIELD OF THE INVENTION

The present invention relates to flame-retarded thermoplastic composition(s) and more particularly to a flame-retarded polycarbonate or polycarbonate blend

composition(s) and articles containing the same, e.g., a flame retarded electric, electronic or automotive component(s).

BACKGROUND OF THE INVENTION

A polycarbonate resin (PC) or a blend (alloy) of a polycarbonate and a styrenic resin such as ABS resin, SAN resin or a blend of polycarbonate and polyester resin such as PBT or PET or a blend of polycarbonate and polymethyl methacrylate (PMMA) or a blend of polycarbonate and polylactic acid (PLA) or three component blend e.g.

PC/PET/PMMA have high heat resistance and impact resistance, so they are generally used for various shaped or molded articles such as parts for an automobile, electric products, an electronic products and the like. When the polycarbonate polymer or its alloys are employed for a housing, an enclosure, a chassis or the like of electric or electronic parts or in office automation (OA) apparatus or instruments, flame-retardancy is required of such a polymer or alloy.

In order to decrease the amount of material and related cost used in the various applications, it is useful to either miniaturize the component or make the part or the housing thinner. Such a miniaturized or thinner part or housing has, however, a risk of a fire drip arising from the miniaturized or thinned part of the shaped article which fire drip can spread fire to another substance in the application. Accordingly, a flame-retarded resin composition is usually required for such a higher flame resistance or flame- retardancy so as to avoid causing such flame drip(s).

For imparting the flame-retardancy, a halogen-containing flame-retardant is usually added to a polycarbonate or polycarbonate alloys comprising a polycarbonate and

l a styrenic resin or a polyester resin or a polymethacrylate resin or a polylactic acid resin. Such halogen-containing flame-retardant may frequently consist of a combination of a bromine-containing flame-retardant exemplified as tetrabromobisphenol A or its oligomer, a brominated epoxy oligomer, and a flame-retarding synergist comprising, as a main component, a metallic oxide exemplified as antimony trioxide. However, some brominated flame retardants have recently fallen under scrutiny in some geographical areas.

In view of the foregoing, what is needed are flame retardants for use in polycarbonate compositions that have improved flame retardancy characteristics while avoiding the problems described above.

SUMMARY OF THE INVENTION

It has been unexpectedly discovered herein that metal phosphonate alone provides significant flame retardant efficiency in aromatic polycarbonate or its alloys, e.g., PC/ABS or PC/PBT or PC/PET or PC/PMMA or PC/PLA or PC/PET/PMMA with a minimal negative effect heat distortion temperature (HDT).

The present invention is directed to a flame retarded polycarbonate composition comprising:

(a) at least one aromatic polycarbonate or polycarbonate based alloy; and,

(b) at least one metal phosphonate.

Further, the present invention is also directed to an electronic, electric or automotive component comprising a polycarbonate or its alloy and a flame retardant additive composition, which composition comprises aluminum methyl methyl phosphonate.

Still further, the present invention is directed to a method of making a flame retarded article comprising blending a polycarbonate or its alloy and aluminum methyl methyl phosphonate.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to flame retarded polycarbonate composition(s) that contains a unique and unexpected combination of polycarbonate resin or its alloys and an effective amount of metal phosphonate. Such flame retarded polycarbonate compositions can be used in electronic or electric or automotive molded parts while providing flame retardancy and maintaining high HDT properties.

The aromatic polycarbonate (a) includes various polymers, for example a polycarbonate obtainable by a reaction of a dihydric phenol compound and phosgene (phosgene method), or by a reaction of a dihydric phenol compound and a carbonic diester (transesterification method). Preferred examples of the dihydric phenol compound include a bisphenol whereby an aromatic polycarbonate having high heat resistance can be obtained. As such bisphenol, there may be mentioned, for instance, a

bis(hydroxyphenyl)alkane such as 2,2-bis(4-hydroxyphenyl)propane, a

bis(hydroxyphenyl)cycloalkane such as bis(4-hydroxyphenyl)cyclohexane, a

dihydroxydiphenyl sulfide, a dihydroxydiphenyl sulfone, a dihydroxydiphenyl ketone and so on. Typically preferred dihydric phenol compound includes, for example, 2,2-bis(4- hydroxyphenyl)propane (namely, bisphenol A) with which a bisphenol A type aromatic polycarbonate can be formed.

In the preparation of the bisphenol A type aromatic polycarbonate, a part of bisphenol A can be replaced by another dihydric phenol compound insofar as the heat resistance, mechanical strength and the like are not adversely affected. In addition to or alternatively to the polycarbonate resin, aromatic polycarbonate component (a) can comprise an alloy of polycarbonate resin and another polymer material.

One example of a polymer material which can be blended with polycarbonate to form a polycarbonate alloy is a styrenic resin (a which includes a non-rubber-modified styrenic resin which does not include a rubber component or a rubber-modified styrenic resin. The rubber-modified styrenic resin may be a mixed composition of a rubber component and a styrenic resin, or a grafted polymer obtainable by graft-polymerizing a styrenic monomer or a mixture of vinyl monomer comprising a styrenic monomer and non-styrenic vinyl monomer to a rubber component which can be used as components of an alloy with polycarbonate resin.

Examples of styrenic monomer include but not limited to styrene, an alkyl- substituted styrene (for instance, o-m ethyl styrene, p-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, p-ethylstyrene, p-t-butylstyrene and the like), an a-alkyl-substituted styrene (e.g. a-methylstyrene, a-methyl-p-methylstyrene, etc.) and others. Preferred examples of the aromatic vinyl monomer include styrene, p-methylstyrene and a- methylstyrene, particularly, styrene and a-methylstyrene. These aromatic vinyl monomers can be employed singly or in combination.

Examples of the non-styrenic monomer include (meth) acrylonitrile, (meth)acrylic monomer (e.g., (meth)acrylic acid ester of an alkyl having about 1 to 4 carbon atoms such as methyl methacrylate), maleic anhydride, N-substituted maleimide and others, specifically acrylonitrile, an alkyl (meth)acrylate such as methyl methacrylate and so on. Such non-styrenic monomers can also be employed singly or in combination.

As the preferred non-rubber modified styrenic resin, there may be mentioned, for instance, SAN resin, a styrene-acrylonitrile-(meth)acrylic acid alkyl ester copolymer and on the like which can be used as components of an alloy with polycarbonate resin. The non-rubber-modified styrenic resin can be used singly or in combination as components of an alloy with polycarbonate resin.

Examples of the rubber component include a polybutadiene, a butadiene- acrylonitrile copolymer, an ethylene-propylene rubber, an EPDM rubber, an acrylic rubber, a styrene-butadiene copolymer and a styrene-butadiene block copolymer as components of an alloy with polycarbonate resin. A polymer containing a butadiene unit (for instance, a polybutadiene. a styrene-butadiene copolymer) may frequently be used as the rubber component as components of an alloy with polycarbonate resin.

The rubber-modified styrenic resin may comprise a mixture of the rubber component and the styrenic resin, or may preferably be a high impact resistant styrenic resin obtainable by graft-polymerizing at least a styrenic monomer to a rubber component as components of an alloy with polycarbonate resin. As examples of the rubber-modified styrenic resin, there may be mentioned a high impact resistant polystyrene (HIPS) obtainable by polymerizing styrene to a polybutadiene, ABS resin obtainable by polymerizing acrylonitrile and styrene to a polybutadiene, AAS resin obtainable by polymerizing acrylonitrile and styrene to a acrylic rubber, ACS resin obtainable by polymerizing acrylonitrile and styrene to a chlorinated polyethylene, AES resin obtainable by polymerizing acrylonitrile and styrene to an ethylene-propylene rubber (or EPDM rubber), a terpolymer obtainable by polymerizing acrylonitrile and styrene to an ethylene- vinyl acetate copolymer, MBS resin obtainable by polymerizing methyl methacrylate and styrene to a polybutadiene and so on. These rubber-modified styrenic resins can be employed singly or as a mixture of two or more species.

The styrenic resin (a may comprise the non-rubber-modified styrenic resin alone, but it may advantageously comprise at least the rubber-modified styrenic resin, specifically the grafted polymer, for improvement or enhancement of the impact resistance as components of an alloy with polycarbonate resin.

One other example of a polymer material which can be blended with

polycarbonate to form a polycarbonate alloy is one or more polyesters (a₂). The polyesters include homo-polyesters and co-polyesters resins, these are resins the molecular structure of which include at least one bond derived from a carboxylic acid, preferably excluding linkages derived from carbonic acid. These are known resins and may be prepared through condensation or ester interchange polymerization of the diol component with the diacid according to known methods. Examples are esters derived from the condensation of a cyclohexanedimethanol with an ethylene glycol with a terephthalic acid or with a combination of terephthalic acid and isophthalic acid. Also suitable are polyesters derived from the condensation of a cyclohexanedimethanol with an ethylene glycol with a 1 ,4-cyclohexanedicarboxylic acid. Suitable resins include poly(alkylene dicarboxylates), especially poly( ethylene terephthalate) (PET), poly( 1 ,4- butylene terephthalate) (PBT), poly(trimethylene terephthalate) (PTT), poly(ethylene naphthalate) (PEN), poly(butylenes naphthalate) (PBN), poly( cyclohexanedimethanol terephthalate) (PCT), poly(cyclohexanedimethanol-co-ethylene terephthalate) (PETG or PCTG), and poly( l ,4-cyclohexanedimethyl-l,4-cyclohexanedicarboxylate) (PCCD) as components of an alloy with polycarbonate resin.

The preferred polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), or mixtures thereof, are particularly useful as components of an alloy with polycarbonate resin.

One still further example of a polymer material which can be blended with polycarbonate to form an polycarbonate alloy is polymethacrylate resin (a3) which can be poly(methyl methacrylate) or methyl methacrylate copolymerized with other

monofunctional monomers such as but not limited to ethyl methacrylate, propyl methacrylate, butyl methacrylate and benzyl methacrylate; methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate; acrylic acid, methacrylic acid, maleic anhydride; styrene, acrylonitrile, methacrylonitrile and the like.

In order to improve compatibility with the polycarbonate resin the

polymethacrylate resin can be copolymenzed with difunctional monomers which contain a vinyl group such as methacrylate and further a different functional group such as an epoxy or hydroxy. Examples of suitable difunctional monomers useful in the present invention may include, but are not limited to, glycidyl methacrylate, allyl glycidyl ether, methacrylic acid anhydride, 2-hydroxy ethyl acrylate, 2-hydroxypropyl acrylate, monoglycerol acrylate, and the like. These difunctional monomers can be used alone or in combination with one another.

One still further example of a polymer material which can be blended with polycarbonate to form a polycarbonate alloy is polymethacrylate resin (a₄) is polylactic acid. Component (¾) here can contain polylactic acid consisting of L-lactic acid monomers, D-lactic acid monomers or mixtures thereof, the mixing ratios of D- or L- lactic acid with the optical antipodes being between 95:5 and 50:50.

Polylactic acids within the meaning of the present invention are also polymers made from lactic acid and/or lactide and at least one other hydroxycarboxylic acid selected from the group comprising glycolic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxypentanoic acid, hydroxycaproic acid and hydroxyheptanoic acid, in each case also in enantiomerically pure form or as a mixture of enantiomers, and mixtures thereof. In particular, glycolic acid, 3-hydroxylactic acid, 4-hydroxybutanoic acid, 3- hydroxyvaleric acid or 6-hydroxycaproic acid are used.

The content of lactic acid in the mixtures is preferably at least 50 wt % and more preferably at least 80 wt. %.

The polylactic acid preferably has a glass transition temperature of about 55-60° C. a melting point of about 175-180° C the specific density of about 1.20-1.25 g/cm³ and the molecular weight (Mw) as determined by gel permeation chromatography with polystyrene standard of about 15,000 to 150,000.

The polycarbonate based alloy (a) can be prepared by melting and mixing the polycarbonate and the styrenic resin (ai ) or the polyester resin (a₂) or the polymethacrylate resin (a₃) or polylactic acid (a₄) or the mixtures thereof. The mixing can be performed in a twin screw extruder and the pellets of the alloy can be produced.

Alternatively the alloy can be prepared during mixing of the polycarbonate flame retardant composition including melting and mixing the polycarbonate and the styrenic resin (aj) or the polyester resin (a2) or the polymethacrylate resin (a₃) or polylactic acid (a4) or the mixtures thereof and metal phosphonate (b).

The ratio of the polycarbonate relative to the styrenic resin (a or the polyester resin (ai) or the polymethacrylate resin (a₃) or polylactic acid (04) or the mixtures thereof can be selected from the range according to the species of each of the resins insofar as not impairing the heat resistance, the impact resistance, the melt fluidity and the like, and is for example such that the former/the latter is about 40/60 to 95/5 (% by weight), preferably about 50/50 to 95/5 (% by weight) and more preferably about 55/45 to 85/15 (% by weight). Use of the polycarbonate in a proportion of less than 40% by weight is apt to decrease or reduce the heat resistance or the impact resistance of the shaped article, although the melt fluidity is in high level in such case. When the proportion of the polycarbonate (a) exceeds 95% by weight, the melt fluidity during the molding process is liable to be decreased.

Specifically, the polycarbonate or polycarbonate based alloy (a) is present in the flame retarded polycarbonate composition in the range from about 50 wt% to about 99 wt% and more specifically in the range from about 75 wt% to about 98 wt% based on the total weight of the flame retarded polycarbonate composition.

The metal phosphonate (b) used herein can be a salt of alkyl alkylphosphonic acid or a salt of aryl alkylphosphonic acid. In one embodiment the salt of alkyl

alkylphosphonic acid or salt of aryl alkylphosphonic acid can be such that the alkyl group and/or aryl group contains up to about 12 carbon atoms. In a further embodiment the metal phosphonate (b) is represented by general formula (I):

where Me is a metal, n is equal to the valency of the metal and is an integer of from 1 to 4, specifically 2 or 3, R¹ is a linear or branched alkyl of up to about 12 carbon atoms, specifically up to about 4 carbon atoms, R² is a linear or branched alkyl of up to about 12 carbon atoms, specifically from up to about 4 carbon atoms or a substituted aryl or an unsubstituted aryl of general formu

where R³ is hydrogen, or a branched or linear alkyl of up to about 4 carbon atoms, or an -NH₂, -CN, or -N0₂ group.

In one specific embodiment, R and/or R^" are each independently methyl or ethyl radicals.

Metals, i.e., Me of the above formula (1), include alkaline earth or transition metals such as the non-limiting group consisting of Ca, Mg, Zn, Al, Fe, Ni, Cr, Ti. The most specific metal is Al.

In one embodiment the metal phosphonate (b) of the formula (I) is an aluminum salt of methyl methylphosphonic acid (AMMP), where Me is aluminum, R¹ and R² are both methyl and n=3. AMMP contains a high level (i.e., 26 weight percent) of active phosphorus. AMMP can be synthesized either by reacting methyl methylphosphonate with an aqueous solution of sodium hydroxide followed by precipitation with aluminum chloride, or by direct reaction of aluminum hydroxide with methyl methylphosphonate at about 180° C in a high shear mixer.

Specifically, the metal phosphonate (b) is present in the flame retarded

polycarbonate composition in the range from about 1 wt% to about 50 wt% and more specifically in the range from about 2 wt% to about 25 wt% and most specifically from about 2 wt% to about 15 wt% based on the total weight of the flame retarded

polycarbonate composition.

In one non-limiting embodiment the flame retarded polycarbonate composition can further comprise an aromatic phosphate ester (c) as an optional component, in that it may be beneficial to use one or more aromatic phosphate ester in the polycarbonate flame retarded composition because phosphate esters may improve melt flow of the

composition. In one embodiment, the aromatic phosphate ester can be represented by the following formula (III): R¹— O— P-j - X— O— P-}-0— R³

o o

2^R4 (III)

wherein R¹, R², R³ and R⁴ are each independently selected from an aryl group or alkyl substituted aryl group containing from up to about 12 carbon atoms, X is an arylene or bisphenylene group containing from 6 to about 18 carbon atoms. The phosphate may be a low molecular weight phosphate such as a monophosphate wherein n is 0 and as such will typically have a molecular weight less than about 500. The phosphate may also contain an oligomeric phosphate wherein n has an average value of from 0 to 5 in which case the weight average molecular weight of the phosphate is at least about 500 and more specifically about 500 to about 2000. Alternatively, the phosphate can be a mixture of any of the phosphates described herein. Mixtures of monophosphates with higher molecular weights phosphates are especially useful for balancing physical properties such as melt viscosity and heat deflection temperature of the polycarbonate compositions described herein.

In the above formula (III) for the phosphates of the invention, the aryl groups may be aryl or an alkyl substituted aryl group (i.e. alkaryl group) containing up to about 12 carbon atoms. More specifically, the aryl groups are independently selected from phenyl, cresyl, xylyl, propylphenyl and butylphenyl groups. The arylene or bisphenylene group is derived from a dihydric compound and is more specifically resorcinol, hydroquinone or bisphenol-A. The aryl groups (R¹, R\ R³ and R⁴) are more specifically phenyl. In the case of the oligomeric phosphates, the more specific aryl phosphate ester is hydroquinone bis(diphenyl phosphate) wherein n is from 1 to about 2, with diphosphate with n=l being the main component of the mixture. X is hydroquinone and each of the R groups is phenyl.

The aromatic phosphate ester will be present in the polycarbonate flame retarded composition in an amount of from about 1 to about 25 weight percent, more specifically from about 2 to about 15 weight percent based on the weight of the polycarbonate flame retarded composition. In one non-limiting embodiment herein the flame retarded polycarbonate composition is in the absence of an aromatic phosphate ester.

In another non-limiting embodiment, the flame retarded polycarbonate

composition is in the absence of a nitrogen-containing compound, such as in the absence of melamine salts.

In one non-limiting embodiment the flame retarded polycarbonate composition is in the absence of hydroquinone bis(diphenyl phosphate).

In one non-limiting embodiment the flame retarded polycarbonate composition is in the absence of halogenated flame retardant, excluding PTFE.

The flame retarded polycarbonate composition herein optionally contains a tetrafluoroethylene polymer, also referred to as PTFE, as antidripping agent. Suitable tetrafluoroethylene polymers for use in this invention typically have a fibril structure which tends to stabilize the polymer under molten conditions. The PTFE can be added to the thermoplastic resin composition as a direct solid or as a concentrate with a resin such as polycarbonate or SAN. Typically PTFE is added at the level from about 0.01 to about 2.0 but more specifically from about 0.1 to about 0.5 weight percent of the total weight of flame retarded thermoplastic composition.

The above amounts of the metal phosphonate. aromatic phosphate ester and PTFE in the flame retarded polycarbonate composition are flame retardant effective amounts of the flame retardant additives.

The thermoplastic polymer composition herein can have a flame retardancy rating of HB, V-2, V-l , V-0 and 5VA according to UL-94 protocol. In one embodiment the polycarbonate flame retarded composition can have a flame retardancy rating of at least V-l or V-0 as is required in most electronic applications.

Other ingredients that can be employed in amounts less than 15 percent by weight of the flame retarded polycarbonate composition, specifically less than 5 percent by weight, include the non-limiting examples of impact modifiers, compatibilizers, colorants, lubricants, heat stabilizers, light stabilizers and other additives used to enhance the properties of the resin.

The method of blending the components of the flame retarded thermoplastic composition herein is not critical and can be carried out by conventional techniques. One convenient method comprises blending the polycarbonate (a) or compounded

polycarbonate alloy or the polycarbonate resin and components of the polycarbonate alloy (ai, a₂. a and 8 ), the metal phosphonate (b) and optionally aromatic phosphate ester (c) in powder or granular form, extruding the blend and compounding the extruded blend into pellets or other suitable shapes. In order to improve handling and avoid dusting, the metal phosphonate (b) can be pre-compounded with the polycarbonate resin or component(s) of the polycarbonate alloy (a), for example styrenic resin and blended as a masterbatch in the form of pellets. If aromatic phosphate ester (c) is used, it can be in one embodiment, a liquid which is fed to the extruder using liquid feeding equipment, e.g. metering pumps. Alternatively, the metal phosphonate (b) can be dispersed in the aromatic phosphate ester (c) using high shear mixer and fed into extruder using liquid feeding equipment.

The polycarbonate flame retarded composition can be molded in any equipment conventionally used for thermoplastic compositions. If necessary, depending on the molding properties of the polycarbonate or polycarbonate based alloy (a), the amount of additives, the resin flow and the rate of solidification of the resin, those skilled in the art will be able to make the conventional adjustments in molding cycles to accommodate the composition.

In another embodiment herein there is provided a molded article comprising the polycarbonate flame retarded composition, specifically where the molded article is made by injection molding the contents of the blended flame retarded polycarbonate composition.

The flame retarded polycarbonate composition of the present invention is useful, for example, in the production of electronic, electrical or automotive components, such as for example, a housing, an enclosure, a chassis, a car underhood electronic part or the like.

The following examples are used to illustrate the present invention. EXAMPLES

In order to prepare samples of flame retarded polycarbonate composition that illustrate the invention, the following procedures have been used. Materials.

Ai - Polycarbonate, PC, Lexan 141-1 1 1 ex. Sabic

A₂ - Polycarbonate, PC, Makrolon 1 143 ex. BayerMaterialScience

bi - Acrylonitrile-butadiene-styrene, ABS, Cycolac C-8707 ex. Sabic

b - Poly(butylene terephthalate), PBT, Celanex 2500 ex. Ticona

b₃ - Polylactic acid, PLA, PLA 325 ID ex. NatureWorks

ci - Aluminum methyl methylphosphonate, AMMP ex. ICL-IP

c₂ - Masterbatch of 50 wt. % AMMP in ABS (Cycolac C-8707), (Example 1) c₃ - Hydroquinone bis(diphenyl phosphate), HDP ex. ICL-IP

c₄ -Resorcinol bis(diphenyl phosphate), Fyrolflex RDP, ex. ICL-IP

c₅ - Suspension of 20 wt. % AMMP in RDP, ex. ICL-IP (Example 2)

d| - Antidripping agent - poly(tetrafluoroethylene), PTFE, Teflon 6C ex. DuPont d₂ - Antidripping agent - poly(tetrafluoroethylene), PTFE, Hostaflon-2071 ex. Dyneon ei - Antioxidant - Hindered phenol and hindered phosphite, Irganox B-225 ex. BASF fi - Impact modifier - random terpolymer of ethylene, methyl acrylate and glycidyl methacrylate, Lotader AX8900, ex. Arkema

f₂ - Compatibilizer -maleic anhydride modified ethylene-a-polyolefin, Bondyram 7107, ex. Polyram

f₃ - Compatibilizer - maleic anhydride modified ethylene-a-polyolefin, Bondyram 3401, ex. Polyram

Compounding

Polymers pellets were dried in a circulating air oven over night at 80°C or at 120°C for 4 hours. The polymers pellets, flame retardant additives, antidriping agents, stabilizers, impact modifiers and compatibilizers were weighted on a semi analytical scale with consequent manual mixing in plastic bags. The mixtures were introduced into the main feeding port of the extruder.

Compounding of PC, PC/ABS alloys and production of 50 wt. % AMMP masterbatch in ABS was performed on Brabender Plasti-Corder PL-2000 twin screw extruder. Compounding of PC/PBT and PC/PLA alloys was performed on a co-rotating Berstorff ZE25 twin screw extruder. The extruded strands were cooled in water tray and pelletized by cutting.

PC and PC/ABS based compositions were compounded at 205-265°C.

PC/PBT based compositions were compounded at 220-260°C.

PC/PLA based compositions were compounded at 160-260°C

The compounded pellets were dried in a circulating air oven over night at 80°C or at 120°C for 4 hours.

Injection molding.

Test specimens were prepared by injection molding in Allrounder 500-150 ex. Arburg.

PC and PC/ABS based compositions were molded at 260°C.

PC/PBT based compositions were molded at 240-270°C.

PC/PLA based compositions were molded at 240-260°C

Test methods.

Before testing, specimens were conditioned at 23°C for 168 hours.

Vertical flammability test - UL-94 V protocol, specimen thickness 1.6 and 3.2 mm. Heat distortion temperature, HDT - ASTM D648, DDT/VICAT Plus Davenport ex. Lloyd Instruments Tester-Tinius Olson DS-5

Tensile properties- ASTMD638, Zwick/Roell Z010 or Instron material testing machine. Notched Izod impact - ASTM D256, Zwick 5102 or TMI pendulum impact tester.

Melt flow index, MFI - ASTM D1238, Meltflixer 2000, ex. Thermo Hake

Glow wire ignition test, GWIT - CEI EN 60695-2-13/1 1 , PTL Dr. Grabenhorst apparatus.

Example 1

A mixture of 50 wt. % AMMP and 50 wt. % ABS was placed into a polyethylene bag and carefully mixed by shaking. The mixture was fed into the main feeding port of Brabender extruder operating at 190-230 °C and 90 rpm. 50wt. % AMMP masterbatch (ci) was produced. Since the polymer string coming from the die of the extruder was brittle it was collected in the water try first and pelletized afterwards using Conair Model 304 pelletizer. Obtained pellets were dried in air circulating oven at 85°C over night.

Example 2

800 g resorcinol bis(diphenyl phosphate) Fyrolflex RDP was placed in two litter stainless steel beaker. Then Cowles high shear dispersion head of Ika Ultra Turrax Model T50 mixer was placed in the beaker and rotation speed was adjusted at 1000 rpm. 200 g of AMMP was slowly added to the beaker over time of 4.5 min. Then rotation speed was increased to 1200 rpm and mixing continued for two more minutes. The obtained 20 wt. % AMMP dispersion in RDP (as) was stored for one week at room temperature and no visual precipitation was observed.

Examples 3-1 1 and Comparative example 1.

Table 1 shows composition, combustion and physical properties of flame retarded PC compositions. V-0 UL-94 rating was achieved at 5 wt. % AMMP and 0.2 wt. PTFE with only minor decrease of HDT (Example 6). Izod impact properties improved with addition of the impact modifier (Examples 8-1 1 ).

Examples 12-17 and Comparative example 2.

Table 2 shows composition, combustion and physical properties of flame retarded PC/ABS compositions. V-0 UL-94 rating at 3.2 mm thickness was achieved at 7 wt. % RDP/AMMP (4: 1 ) suspension and 0.2 wt. PTFE (Example 12). As it is seen HDT increased from 81 °C (Comparative example 2) to 91 °C of HDT. Further increase of RDP/AMMP suspension resulted in improving flame retardancy, since V-0 rating was achieved at 1.6 mm (Example 14) but Izod impact and HDT decreased.

Table 2. Composition, combustion and physical properties of

flame retarded PC/ABS com ositions

Examples 18-21 and Comparative example 3

Table 3 shows composition, combustion and physical properties of flame retarded PC/PBT compositions. V-0 UL-94 rating was achieved at 5wt. % HDP (Example 18) or 4 wt. % AMMP (Example 19) or 2.5 wt. % HDP + 2.5 wt. % AMMP (Example 20) in combination with 0.5 wt. % PTFE. Addition of the impact modifiers helped to improve Izod impact properties but UL-94 rating droped to V-l (Example 21 ) even when the loading of AMMP was increased to 10 wt.%. Table 3. Composition, combustion and physical properties of

flame retarded PC/PBT compositions

Comparative

Example 18 ,9 20 21

Example 3

Composition, wt. %

A₂ j 69.5 66.0 66.7 66.0 57.3 b₂ 29.8 28.3 28.6 28.3 24.5

Ci 4.0 2.5 10

C3 5.0 2.5

d₂ 0.5 0.5 0.5 0.5 0.5 ei 1 0.2 0.2 0.2 0.2 0.2 fi ! 7.5

UL-94, 1.6 mm NR V-0 V-0 V-0 V-l

Tensile properties

Strength, N/mm² j 72 73 74 71 50

Elongation at yield, % 7 7 6 6 6

Elongation at break, % ! 16 54 12 12 40

Modulus, N/mm^" 2525 2680 2785 2945 1925

Izod Impact, J/m 82 45 48 42 1 17

MFI, 250°C/5kg, g/10min 14 22 39 44 17

HDT, °C 96 83.5 83.5 81 79

GWIT, °C 775 775 775 775 750

Examples 22-25

Table 4 shows composition, combustion and physical properties of flame retarded PC/PLA compositions. V-0 UL-94 rating was achieved at 7 wt. % AMMP (Example 22) in combination with 0.5 wt. % PTFE. Addition of the impact modifier (Example 23) or compatibilizers (Examples 23, 24) helped to improve Izod impact properties but UL-94 rating droped to V-l .

Table 3. Composition, combustion and physical properties of

flame retarded PC/PLA compositions

Izo Impact, m

While the invention has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

1. A flame retarded polycarbonate composition comprising:

(a) at least one aromatic polycarbonate or polycarbonate based alloy; and,

(b) at least one metal phosphonate.

2. The flame retarded polycarbonate composition of Claim 1 where the

polycarbonate is bisphenol A aromatic polycarbonate.

3. The flame retarded polycarbonate composition of Claim 1 where the

polycarbonate based alloy is selected from the group consisting of PC/ABS, PC/SAN, PC PBT, PC/PET, PC PMMA, PC/PLA, PC/PET/PMMA and PC/PBT/PMMA

4. The flame retarded polycarbonate composition of Claim 1 where the metal phosphonate is represented by general formula (I):

where Me is a metal, n is equal to the valency of the metal which is an integer of from 1 to 4, R¹ is a linear or branched alkyl of up to about 12 carbon atoms, R² is a linear or branched alkyl of up to about 12 carbon atoms, or a substituted aryl or an unsubstituted aryl of the general formula (II):

where R³ is hydrogen, or a branched or linear alkyl of up to about 4 carbon atoms, or a -NH₂, -CN, or -N0₂ group.

5. The flame retarded polycarbonate composition of claim 1 where the metal phosphonate is aluminum methyl methylphosphonate.

6. The flame retarded polycarbonate composition of Claim 1 wherein the polycarbonate or polycarbonate based alloy (a) is present in an amount of from about 50 to about 99 weight percent; and, the metal phosphonate (b) is present in an amount of from about 1 to about 50 weight percent, with each weight percent being based on the total weight of the flame retarded polycarbonate composition.

7. The flame retarded polycarbonate composition of Claim 1 wherein the polycarbonate or polycarbonate based alloy (a) is present in an amount of from about 75 to about 98 weight percent; and, the metal phosphonate (b) is present in an amount of from about 2 to about 25 weight percent, with each weight percent being based on the total weight of the flame retarded polycarbonate composition.

8. The flame retarded polycarbonate composition of Claim 1 further comprising at least one antidripping agent.

9. The flame retarded polycarbonate composition of Claim 1 further comprising at least one impact modifier.

10. The flame-retarded polycarbonate composition of Claim 1 wherein the composition is in the absence of an aromatic phosphate ester.

1 1. A molded article comprising the flame retarded polycarbonate composition of Claim 1.

12. The molded article of Claim 1 1 which is selected from the group consisting of an electric component, an electronic component, or an automotive component.