Title of Invention

"FLAME-RESISTANT POLYCARBONATE COMPOSITIONS WITH PHOSPHORUS-SILICON COMPOUNDS"

Abstract The present invention concerns polycarbonate compositions rendered flame resistant with phosphorus-silicon compounds having high thermal stability and low volatility. Preferred phosphorus-silicon compounds are produced by thermal oligomerisation from phosphorylated silanes.
Full Text Flame-resistant polycarbonate compositions with phosphorus-silicon compounds
The present invention concerns polycarbonate compositions rendered flame resistant " with phosphorus-silicon compounds having high thermal stability and low volatility. Preferred phosphorus-silicon compounds are produced by thermal oligomerisation from phosphorylated si lanes.
In order to satisfy the stringent requirements that exist in many areas of application regarding the flame resistance of the materials used, plastics generally have to contain flame retardants. A large number of substances that are suitable as flame retardants are known and are also commercially available. Halo compounds, phosphorus compounds, silicon compounds, zinc borates and metal hydroxides can be cited by way of example. By virtue of the often more advantageous secondary effects of fire in terms of smoke density, toxicity and corrosiveness and in particular for ecotoxicological reasons, the use of halogen-free flame retardant systems is preferred.
Flame-retardant polycarbonate compositions are known in principle and are used in a variety of areas of application, in particular in the electrical and electronics sector, in data technology, in construction and in the aircraft and railway industry. Phosphorus compounds, phosphorus-nitrogen compounds and silicon compounds are described in particular as suitable halogen-free flame retardants.
The use of phosphorus compounds, in particular of monomelic and oligomeric phosphoric acid esters as flame retardants in PC/ABS compositions is described for example in EP-A 0 345 522, EP-A 0 363 608 and EP-A 0 640 655. In addition to their suitability as a flame retardant additive, phosphoric acid esters display a plasticising action. The heat resistance of the compositions is therefore substantially reduced in some cases if they are rendered flame resistant.
The use of phosphorus-nitrogen compounds, such as phosphonate amines, phosphazenes and phosphoratnidates as flame retardants in polycarbonate compositions is described for example in WO 01/18106, EP-A 1 116 772, EP-A 0 728 811, US-A 6,414,060, US-A 5,973,041 and WO 00/12612. In comparison to the aforementioned phosphoric acid esters these compounds are generally far less plasticising, but at the elevated temperatures that are typical in the compounding and processing of polycarbonate compositions they have a tendency towards thermal decomposition and/or degradation of the polycarbonate.
The use of silicon compounds, in particular of special silicones, as flame retardants in polycarbonate compositions is described for example in US-A 6,001,921, WO 99/28387, WO 00/39217, WO 00/46299 and WO 00/64976. The silicones used can be incorporated into polycarbonate without any significant reduction in molecular weight, are thermally stable and have little or no plasticising action on the polycarbonate. The disadvantage of silicones is their comparatively low flame retardant efficiency, which limits their use to pure, i.e. non-impact-modified polycarbonate. The use of silicones alone to render blends such as PC/ABS blends flame retardant, at least by any economically viable means, is not possible.
Due to their lack of adequate efficiency, silicones are frequently used in combination with other flame retardants, such as the aforementioned phosphorus compounds for example. US 2002/0099160 Al is cited here by way of example, wherein a combination of a special silicone and an oligomeric phosphoric acid ester is described as a flame retardant package for PC/ABS blends. The addition of silicone allows the amount of phosphate needed for a flame retardant effect to be reduced and hence its undesirable plasticising effect in some high-temperature applications to be limited, but not absolutely prevented.
JP-A 2001-247582 describes phosphorylated polyorganosiloxanes as low-plasticising flame retardants for polycarbonate and PC/ABS blends. Due to their
poor compatibility with the polycarbonate and their in some cases high volatility at the conventional processing temperatures, the compounds used here as a flame retardant additive tend to bleed, which can lead to problems in injection moulding in particular because of downtimes.
The object of the present invention was therefore to develop novel phosphorus-silicon compounds having high flame retardant efficiency, high thermal stability, low volatility and good compatibility with aromatic polycarbonates and to use them to provide flame-resistant polycarbonate compositions having improved processing characteristics.
Surprisingly it was found that polycarbonate compositions to which special phosphorus-silicon compounds are added display the desired range of properties.
The present invention therefore provides polycarbonate compositions containing low-volatility phosphorus-silicon compounds having a phosphorus content of 1 to 20 wt.%, in particular 3 to 17 wt.%, preferably 5 to 15 wt.%, particularly preferably 7 to 13 wt.%, and a silicon content of 1 to 20 wt.%, in particular 3 to 17 wt.%, preferably 5 to 15 wt.%, particularly preferably 7 to 13 wt.%, which at 280°C display a volatile content by mass of less than 30 wt.%, preferably less than 20 wt.%, particularly preferably less than 15 wt.%, in particular less than 10 wt.%, most particularly preferably less than 5 wt.% (assessed in a thermogravimetric analysis under nitrogen inert gas at a heating-up rate of 20 K/min), the cited weights referring in each case to the phosphorus-silicon compound.
Production processes for phosphorus-silicon compounds that are suitable according to the invention as a flame retardant or flame retardant synergist for polycarbonate compositions are known in principle. Examples of processes for producing such compounds can be found in Phosphorus, Sulfur, and Silicon 68 (1992) 107-114 and the literature cited therein. The processes described therein and resulting compounds
should be regarded as examples only, however, and in no way restrict the scope of the present invention.
Such phosphorus-silicon compounds that can be obtained by thermally induced oligomerisation from phosphorylated silanes, for example, are preferably used.
The phosphorylated silanes are produced for example with liberation of hydrogen halide, chloromethane or chloroethane in the reaction of phosphonic acid esters having the general formula (I) with halosilanes having the general formula (II),
(Formula Removed)
wherein
n represents a number between 0 and 3, preferably 2,
X represents a halogen atom, preferably chlorine or bromine,
R1 mutually independently represents hydrogen or C1-C4 alkyl, preferably methyl or ethyl,
R2 represents
a) an aryl radical optionally substituted with aryl (e.g. phenyl) or alkyl (e.g. C1-C4-alkyl), preferably phenyl, or
b) an alkyl radical optionally substituted with aryl (e.g. phenyl), preferably methyl, ethyl, propyl or butyl, or
c) an aryloxy radical optionally substituted with aryl (e.g. phenyl) or alkyl (e.g. C1-C4-alkyl), preferably phenoxy, or
d) an alkoxy radical optionally substituted with aryl (e.g. phenyl), preferably methoxy, ethoxy or propoxy, or
e) hydrogen, and
R3 mutually independently represents the same or different alkyl radicals, preferably C1-C8 alkyl, in particular methyl, ethyl, propyl and butyl, aryl radicals or aryl radicals substituted with alkyl, preferably C1-C4 alkyl, in particular phenyl, cresyl, xylenyl, propyl phenyl or butyl phenyl.
The phosphorylated silanes or alternatively also mixtures of such phosphorylated silanes are thermally oligomerised at temperatures above 70°C, in particular above 100°C, preferably above 130°C, the resulting monomeric phosphonate being removed from the reaction mixture by continuous distillation in vacuo.
Examples of phosphorus-silicon compounds that are particularly preferably suitable as a flame retardant additive are those having the general formula (III),
(Formula Removed)
wherein
R1, R2 and R3 have the meaning cited above and
m denotes a numerical value from 2 to 1000, preferably from 2 to 100, in
particular from 2 to 20, by preference from 2 to 10, and
wherein the radicals R2 and R3 can vary within the polymer chain from one monomer unit to another.
Such compounds having the general formula (III) in which at least 10 mol%, preferably at least 20 mol%, in particular at least 30 mol%, particularly preferably at least 40 mol%, most particularly preferably at least 50 mol% of the substituents R2 and R3 are aryl or aryloxy radicals, preferably phenyl or phenoxy, are used in particular.
Phosphorus-silicon compounds that are preferably used as a flame retardant additive are furthermore those having the general formula (IV),
(Formula Removed)
wherein
R2 has the meaning cited above and
R3 stands for the same or different aryl radicals, in particular for phenyl, cresyl
and xylyl.
The phosphorylated silanes having formula (IV) can likewise be obtained with liberation of hydrogen halide, chloromethane or chloroethane from the reaction of corresponding phosphonic acid esters having the general formula (I) with corresponding halosilanes having the general formula (II).
Naturally, mixtures of different phosphorus-silicon compounds according to the invention can also be used as flame retardants.
The phosphorus-silicon compounds are used in the polycarbonate compositions to be rendered flame resistant in quantities of 0.05 to 30 parts by weight, preferably 0.1 to 20 parts by weight, in particular 0.2 to 15 parts by weight, particularly preferably 0.3 to 10 parts by weight, most particularly preferably 0.5 to 5 parts by weight, most preferably of all 1.5 to 8 parts by weight, relative to 100 parts by weight of polycarbonate composition. The optimum amount of compounds according to the invention to use depends on the nature of the polycarbonate composition, i.e. on any addition of other polymers and/or impact modifiers, the nature of auxiliary substances additionally used and the type of compound used according to the invention.
The polycarbonate compositions that can be rendered flame resistant with the phosphorus-silicon compounds contain
A) 60 to 100 parts by weight, preferably 70 to 100 parts by weight, in particular 80 to 100 parts by weight, particularly preferably 90 to 100 parts by weight, most particularly preferably 93 to 100 parts by weight of aromatic polycarbonate and/or polyester carbonate,
B) 0 to 40 parts by weight, preferably 0 to 30 parts by weight, in particular 0 to 25 parts by weight, particularly preferably 0 to 10 parts by weight, most particularly preferably 0 to 5 parts by weight of at least one polymer selected from vinyl (co)polymers, rubber-modified vinyl (co)polymers and aromatic polyesters,
C) 0 to 5 parts by weight, preferably 0 to 2 parts by weight, in particular 0 to 1 parts by weight, particularly preferably 0 to 0.5 parts by weight, most particularly preferably 0.2 to 0.5 parts by weight of fluorinated polyolefin and
D) up to 20 parts by weight, preferably up to 15 parts by weight, in particular up to 10 parts by weight, particularly preferably up to 5 parts by weight, most
particularly preferably up to 2 parts by weight of other polymers and/or polymer additives,
the parts by weight of components A to D adding to 100.
Component A
Aromatic polycarbonates and/or aromatic polyester carbonates in accordance with component A that are suitable according to the invention are known from the literature or can be prepared by methods known from the literature, such as the interfacial polycondensation process or the melt polymerisation process for example (for the preparation of aromatic polycarbonates see for example Schnell, "Chemistry and Physics of Polycarbonates", Interscience Publishers, 1964 and DE-AS 1 495 626, DE-A 2 232 877, DE-A 2 703 376, DE-A 2 714 544, DE-A 3 000 610, DE-A 3 832 396; for the preparation of aromatic polyester carbonates e.g. DE-A 3 077 934).
Aromatic polycarbonates are prepared for example by reacting diphenols with carbonic acid halides, preferably phosgene, and/or with aromatic dicarboxylic acid dihalides, preferably benzenedicarboxylic acid dihalides, by the interfacial polycondensation process, optionally using chain terminators, for example monophenols, and optionally using trifunctional or polyfunctional branching agents, for example triphenols or tetraphenols.
Diphenols for the preparation of the aromatic polycarbonates and/or aromatic polyester carbonates are preferably those having the formula (V)
(Formula Removed)
wherein
A is a single bond, C1 to C5 alkylene, C2 to C5 alkylidene, C5 to C6
cycloalkylidene, -O-, -SO-, -CO-, -S-, -SO2-, C6 to C12 arylene, to which other aromatic rings optionally containing heteroatoms can be condensed,
or a radical having the formula (VI) or (VII)
(Formula Removed)
B is C1 to C12 alkyl, preferably methyl, halogen, preferably chlorine and/or
bromine
x is mutually independently 0, 1 or 2,
p is 1 or 0, and
R5 and R6 can be individually selected for each X1 and mutually independently denote hydrogen or C1 to C6 alkyl, preferably hydrogen, methyl or ethyl,
X denotes carbon and
m denotes a whole number from 4 to 7, preferably 4 or 5, with the proviso that in at least one X1 atom R5 and R6 are both alkyl.
Preferred diphenols are hydroquinone, resorcinol, dihydroxydiphenols,
bis(hydroxyphenyl)-C1 -C5-alkanes, bis(hydroxyphenyl)-C5-C6-cycloalkanes,
bis(hydroxyphenyl) ethers, bis(hydroxyphenyl) sulfoxides, bis(hydroxyphenyl) ketones, bis(hydroxyphenyl) sulfones and α,α-bis(hydroxyphenyl) diisopropyl benzenes along with their ring-brominated and/or ring-chlorinated derivatives.
Particularly preferred diphenols are 4,4'-dihydroxydiphenyl, bisphenol A, 2,4-bis-(4-hydroxyphenyl)-2-methyl butane, l,l-bis-(4-hydroxyphenyl) cyclohexane, 1,1-bis-(4-hydroxyphenyl-3.3.5-trimethyl cyclohexane, 4,4'-dihydroxydiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfone and dibrominated and tetrabrominated or chlorinated derivatives thereof such as e.g. 2,2-bis-(3-chloro-4-hydroxyphenyl) propane, 2,2-bis-(3,5-dichloro-4-hydroxyphenyl) propane or 2,2-bis-(3,5-dibromo-4-hydroxyphenyl) propane. 2,2-bis-(4-hydroxyphenyl) propane (bisphenol A) is especially preferred.
The diphenols can be used individually or in any combination whatsoever. The diphenols are known from the literature or can be obtained by methods known from the literature.
Suitable chain terminators for the preparation of the thermoplastic, aromatic polycarbonates are for example phenol, p-chlorophenol, p-tert.-butyl phenol or 2,4,6-tribromophenol, as well as long-chain alkyl phenols such as 4-(l,3-tetramethyl butyl) phenol according to DE-A 2 842 005 or monoalkyl phenol or dialkyl phenols having
a total of 8 to 20 C atoms in the alkyl substituents, such as 3,5-di-tert.-butyl phenol, p-iso-octyl phenol, p-tert.-octyl phenol, p-dodecyl phenol and 2-(3,5-dimethyl heptyl) phenol and 4-(3,5-dimethyl heptyl) phenol. The amount of chain terminators to be used is generally between 0.5 mol% and 10 mol%, relative to the molar sum of diphenols used in each case.
The thermoplastic, aromatic polycarbonates can be branched by known means, and preferably by the incorporation of 0.05 to 2.0 mol%, relative to the sum of diphenols used, of trifunctional or polyfunctional compounds, for example those having three and more phenolic groups.
Both homopolycarbonates and copolycarbonates are suitable. 1 to 25 wt.%, preferably 2.5 to 25 wt.% (relative to the total amount of diphenols to be used) of polydiorganosiloxanes having hydroxyaryloxy terminal groups can also be used in the production of copolycarbonates according to the invention in accordance with component A. These are known (e.g. US-A 3 419 634) or can be produced by methods known from the literature. The production of polydiorganosiloxane-containing copolycarbonates is described e.g. in DE-A 3 334 782.
In addition to the bisphenol A homopolycarbonates, preferred polycarbonates are the copolycarbonates of bisphenol A having up to 15 mol%, relative to the molar sums of diphenols, of other diphenols cited as being preferred or particularly preferred.
Aromatic dicarboxylic acid dihalides for the production of aromatic polyester carbonates are preferably the di-acid dichlorides of isophthalic acid, terephthalic acid, diphenyl ether-4,4'-dicarboxylic acid and naphthaline-2,6-dicarboxylic acid.
Mixtures of aromatic dicarboxylic acid dihalides can also be used, mixtures of the di-acid dichlorides of isophthalic acid and terephthalic acid in a ratio between 1:20 and 20:1 being particularly preferred.
In the production of polyester carbonates a carbonic acid halide, preferably phosgene, is also incorporated as a bifunctional acid derivative.
Examples of chain terminators for the production of aromatic polyester carbonates also include, in addition to the monophenols already cited, chloroformic acid esters thereof and the acid chlorides of aromatic monocarboxylic acids, which can optionally be substituted by C1 to C22 alkyl groups or by halogen atoms, along with aliphatic C2 to C22 monocarboxylic acid chlorides.
The quantity of chain terminators in each case is 0.1 to 10 mol%, relative to moles of diphenols in the case of phenolic chain terminators and to moles of dicarboxylic acid dichlorides in the case of monocarboxylic acid chloride chain terminators.
The aromatic polyester carbonates can also contain incorporated aromatic hydroxycarboxylic acids.
The aromatic polyester carbonates can be both linear and branched by known means (see also DE-A 2 940 024 and DE-A 3 007 934 in this connection).
Examples of branching agents that can be used include trifunctional or
polyfunctional carboxylic acid chlorides, such as trimesic acid trichloride, cyanuric
acid trichloride, 3,3'-,4.,4'-benzophenone tetracarboxylic acid tetrachloride, 1,4,5,8-
naphthaline tetracarboxylic acid tetrachloride or pyromelhtic acid tetrachloride, in
quantities of 0.01 to 1.0 mol% (relative to dicarboxylic acid dichlorides used) or
trifunctional or polyfunctional phenols, such as phloroglucinol, 4,6-dimethyl-2,4,6-
tri-(4-hydroxyphenyl) heptene-2,4,4-dimethyl-2,4,6-tri-(4-hydroxyphenyl) heptane,
l,3,5-tri-(4-hydroxyphenyl) benzene, 1,1,1-tri-(4-hydroxyphenyl) ethane, tri-(4-
hydroxyphenyl) phenyl methane, 2,2-bis-[4,4-bis-(4-hydroxyphenyl) cyclohexyl]
propane, 2,4-bis-(4-hydroxyphenyl isopropyl) phenol, tetra-(4-hydroxyphenyl)
methane, 2,6-bis-(2-hydroxy-5-methylbenzyl)-4-methyl phenol, 2-(4-
hydroxyphenyl)-2-(2,4-dihydroxyphenyl) propane, tetra-(4-[4-hydroxyphenyl
isopropyl] phenoxy) methane, 1,4-bis-[4,4'-dihydroxytriphenyl) methyl] benzene, in quantities of 0.01 to 1.0 mol%, relative to diphenols used. Phenolic branching agents can be included with the diphenols, acid chloride branching agents can be introduced together with the acid dichlorides.
The proportion of carbonate structural units in the thermoplastic, aromatic polyester carbonates can vary widely. The proportion of carbonate groups is preferably up to 100 mol%, in particular up to 80 mol%, particularly preferably up to 50 mol%, relative to the sum of ester groups and carbonate groups. Both the ester and the carbonate component of the aromatic polyester carbonates can be in the form of blocks or randomly distributed in the polycondensate.
The thermoplastic, aromatic poly(ester) carbonates have average weight-average molecular weights (Mw, measured e.g. by ultracentrifuge, light-scattering measurement or gel permeation chromatography) of 10,000 to 200,000, preferably 15,000 to 80,000, particularly preferably 17,000 to 40,000.
The thermoplastic, aromatic polycarbonates and polyester carbonates can be used alone or in any combination.
Component B
The polycarbonate compositions according to the invention can contain as
component B at least one other polymer chosen from the group of vinyl
(co)polymers, rubber-modified vinyl (co)polymers and (preferably aromatic)
polyesters.
Preferred rubber-modified vinyl (co)polymers are graft polymers of at least one vinyl monomer on at least one rubber having a glass transition temperature B.l 5 to 95 wt.%, preferably 10 to 90 wt.%, in particular 20 to 70 wt.% of monomers of a mixture comprising
B.l.l 50 to 99 wt.%, preferably 50 to 90 wt.%, particularly preferably 55 to 85 wt.%, most particularly preferably 60 to 80 wt.% of vinyl aromatics and/or ring-substituted vinyl aromatics (such as e.g. styrene, α-methyl styrene, p-methyl styrene, p-chlorostyrene) and/or methacrylic acid (C1-C8) alkyl esters (such as methyl methacrylate, ethyl methacrylate) and
B.l.2 1 to 50 wt.%, preferably 10 to 50 wt.%, particularly preferably 15 to 45 wt.%, most particularly preferably 20 to 40 wt.% of vinyl cyanides (unsaturated nitriles such as acrylonitrile and methacrylonitrile) and/or (meth)acrylic acid (C1-C8) alkyl esters (such as methyl methacrylate, n-butyl acrylate, t-butyl acrylate) and/or derivatives (such as anhydrides and imides) of unsaturated carboxylic acids (for example maleic anhydride and N-phenyl maleinimide) on
B.2 95 to 5 wt.%, preferably 90 to 10 wt.%, in particular 80 to 30 wt.% of one or more rubbers having glass transition temperatures The graft base generally has an average particle size (d50 value) of 0.05 to 10 urn, preferably 0.1 to 5 urn, particularly preferably 0.2 to 1 um.
The average particle size d50 is the diameter above and below which respectively 50 wt.% of the particles lie. It can be determined by ultracentrifuge measurement (W. Scholtan, H. Lange, Kolloid, Z. und Z. Polymere 250 (1972), 782-1796).
Preferred monomers B.l. 1 are selected from at least one of the monomers styrene, a-methyl styrene and methyl methacrylate, preferred monomers B.l.2 are selected

from at least one of the monomers acrylonitrile, maleic anhydride and methyl methacrylate.
Particularly preferred monomers are styrene and acrylonitrile.
Suitable graft bases B.2 for the graft polymers are for example diene rubbers, EP(D)M rubbers, i.e. those based on ethylene/propylene and optionally diene, acrylate, polyurethane, silicone, chloroprene and ethylene/vinyl acetate rubbers, as well as composite rubbers consisting of two or more of the above systems.
Preferred graft bases are diene rubbers. Diene rubbers within the meaning of the present invention are those based e.g. on butadiene, isoprene, etc. or mixtures of diene rubbers or copolymers of diene rubbers or mixtures thereof with other copolymerisable monomers, such as e.g. butadiene-styrene copolymers, with the proviso that the glass transition temperature of the graft base is Pure polybutadiene rubber is particularly preferred.
Particularly preferred graft polymers are e.g. ABS polymers (emulsion, bulk and suspension ABS), such as are described e.g. in DE-A 2 035 390 (=US-PS 3 644 574) or in DE-A 2 248 242 (=GB-PS 1 409 275) or in Ullmanns Enzyklopadie der Technischen Chemie, Vol. 19 (1980), p. 280 ff. The gel content of the graft base is preferably at least 30 wt.%, in particular at least 40 wt.%.
The gel content of the graft base is determined at 25°C in toluene (M. Hoffmann, H. Kromer, R. Kuhn, Polymeranalytik I and II, Georg Thieme-Verlag, Stuttgart 1977).
The graft copolymers can be produced by radical polymerisation, e.g. by emulsion, suspension, solution or bulk polymerisation. They are preferably produced by emulsion or bulk polymerisation.
Particularly suitable graft rubbers are also ABS polymers produced by redox initiation with an initiator system comprising organic hydroperoxide and ascorbic acid according to US-A 4 937 285.
Acrylate rubbers that are suitable as the graft base are preferably polymers of acrylic acid alkyl esters, optionally also copolymers having up to 40 wt.%, relative to the graft base, of other polymerisable, ethylenically unsaturated monomers. The preferred polymerisable acrylic acid esters include C1-C8 alkyl esters, for example methyl, ethyl, butyl, n-octyl and 2-ethylhexyl ester; haloalkyl esters, preferably halogen C1-C8 alkyl esters, such as chloroethyl acrylate, and mixtures of these monomers.
Monomers having more than one polymerisable double bond can be copolymerised for crosslinking. Preferred examples of crosslinking monomers are esters of unsaturated monocarboxylic acids with 3 to 8 C atoms and unsaturated monohydric alcohols with 3 to 12 C atoms, or saturated polyols with 2 to 4 OH groups and 2 to 20 C atoms, such as ethylene glycol dimethacrylate, allyl methacrylate; polyunsaturated heterocyclic compounds, such as trivinyl and triallyl cyanurate; polyfunctional vinyl compounds, such as divinyl and trivinyl benzenes; but also triallyl phosphate and diallyl phthalate.
Preferred crosslinking monomers are allyl methacrylate, ethylene glycol dimethacrylate, diallyl phthalate and heterocyclic compounds displaying at least three ethylenically unsaturated groups.
Particularly preferred crosslinking monomers are the cyclic monomers triallyl cyanurate, triallyl isocyanurate, triacryloyl hexahydro-s-triazine, triallyl benzenes. The quantity of crosslinking monomers is preferably 0.02 to 5, in particular 0.05 to 2 wt.%, relative to the graft base.
In the case of cyclic crosslinking monomers having at least three ethylenically unsaturated groups it is advantageous to restrict the quantity to below 1 wt.% of the graft base.
Preferred "other" polymerisable, ethylenically unsaturated monomers which can optionally serve to produce the graft base in addition to the acrylic acid esters are e.g. acrylonitrile, styrene, a-methyl styrene, acrylamides, vinyl C1-C6 alkyl ethers, methyl methacrylate, butadiene. Preferred acrylate rubbers as the graft base are emulsion polymers displaying a gel content of at least 60 wt.%.
Other suitable graft bases are silicone rubbers having graft-active sites, such as are described in DE-A 3 704 657, DE-A 3 704 655, DE-A 3 631 540 and DE-A 3 631 539.
Preferred suitable vinyl (copolymers are such polymers of at least one monomer from the group of vinyl aromatics, vinyl cyanides (unsaturated nitriles), (meth)acrylic acid (C1 to C8) alkyl esters, unsaturated carboxylic acids and derivatives (such as anhydrides and imides) of unsaturated carboxylic acids. Particularly suitable are (co)polymers comprising
50 to 99, preferably 60 to 80 wt.% of vinyl aromatics and/or ring-substituted vinyl aromatics, such as e.g. styrene, a-methyl styrene, p-methyl styrene, p-chlorostyrene, and/or methacrylic acid (C1 to C8) alkyl esters, such as methyl methacrylate, ethyl methacrylate, and
1 to 50, preferably 20 to 40 wt.% of vinyl cyanides (unsaturated nitriles) such as acrylonitrile and methacrylonitrile and/or (meth)acrylic acid (C1-C8) alkyl esters (such as methyl methacrylate, n-butyl acrylate, t-butyl acrylate) and/or unsaturated carboxylic acids (such as maleic acid) and/or derivatives (such as anhydrides and imides) of unsaturated carboxylic acids (for example maleic anhydride and N-phenyl maleinimide).
The (co)polymers are resinous and thermoplastic.
The copolymer comprising styrene and acrylonitrile along with polymethyl methacrylate is particularly preferred.
The (co)polymers are known and can be produced by radical polymerisation, in particular by emulsion, suspension, solution or bulk polymerisation. The (co)polymers preferably have average molecular weights Mw (weight average, determined by light scattering or sedimentation) of between 15,000 and 200,000.
Preferably suitable polyesters are polyalkylene terephthalates. They are reaction products of aromatic dicarboxylic acids or reactive derivatives thereof, such as dimethyl esters or anhydrides, and aliphatic, cycloaliphatic or araliphatic diols and mixtures of these reaction products.
Preferred polyalkylene terephthalates contain at least 80 wt.%, preferably at least 90 wt.%, relative to the dicarboxylic acid component, of terephthalic acid radicals and at least 80 wt.%, preferably at least 90 mol%, relative to the diol component, of ethylene glycol and/or butanediol-1,4 radicals.
In addition to terephthalic acid radicals, the preferred polyalkylene terephthalates can contain up to 20 mol%, preferably up to 10 mol%, of radicals of other aromatic or cycloaliphatic dicarboxylic acids having 8 to 14 C atoms or aliphatic dicarboxylic acids having 4 to 12 C atoms, such as radicals of phthalic acid, isophthalic acid, naphthaline-2,6-dicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, cyclohexane diacetic acid.
In addition to ethylene glycol or butanediol-1,4 radicals, the preferred polyalkylene terephthalates can contain up to 20 mol%, preferably up to 10 mol%, of other aliphatic diols having 3 to 12 C atoms or cycloaliphatic diols having 6 to 21 C
atoms, e.g. radicals of propanediol-1,3, 2-ethyl propanediol-1,3, neopentyl glycol,
pentanediol-1,5, hexanediol-1,6, cyclohexane dimethanol-1,4, 3-ethyl pentanediol-
2,4, 2-methyl pentanediol-2,4, 2,2,4-trimethyl pentanediol-1,3, 2-ethyl hexanediol-
1,3, 2,2-diethyl propanediol-1,3, hexanediol-2,5, l,4-di-((3-hydroxyethoxy)benzene,
2,2-bis-(4-hydroxycyclohexyl) propane, 2,4-dihydroxy-1,1,3,3-tetramethyl
cyclobutane, 2,2-bis-(4-P-hydroxyethoxyphenyl) propane and 2,2-bis-(4-hydroxypropoxyphenyl) propane (DE-A 2 407 674, 2 407 776, 2 715 932).
The polyalkylene terephthalates can be branched by incorporating relatively small amounts of trihydric or tetrahydric alcohols or tribasic or tetrabasic carboxylic acids, e.g. according to DE-A 1 900 270 and US-PS 3 692 744. Examples of preferred branching agents are trimesic acid, trimellitic acid, trimethylol ethane and propane and pentaerythritol.
Particularly preferred are polyalkylene terephthalates produced solely from terephthalic acid and reactive derivatives thereof (e.g. dialkyl esters thereof) and ethylene glycol and/or butanediol-1,4, and mixtures of these polyalkylene terephthalates.
Preferred mixtures of polyalkylene terephthalates contain 0 to 50 wt.%, preferably 0 to 30 wt.%, of polybutylene terephthalate and 50 to 100 wt.%, preferably 70 to 100 wt.%, of polyethylene terephthalate. Polyethylene terephthalate is particularly preferred.
The polyalkylene terephthalates that are preferably used generally have an intrinsic viscosity of 0.4 to 1.5 dl/g, preferably 0.5 to 1.2 dl/g, measured in phenol/o-dichlorobenzene (1:1 parts by weight) at 25°C in an Ubbelohde viscometer.
The polyalkylene terephthalates can be produced by known methods (e.g. Kunststoff-Handbuch, Volume VIII, page 695 ff., Carl-Hanser-Verlag, Munich
1973).
Component C
Fluorinated polyolefins are optionally used in the polycarbonate compositions as so-called anti-dripping agents, which reduce the tendency of the material to drip as it burns in the event of a fire.
Fluorinated polyolefins are known and described for example in EP-A 0 640 655. They are sold by DuPont, for example, under the brand name Teflon 30N.
The fluorinated polyolefins can be used both in pure form and in the form of a coagulated mixture of emulsions of the fluorinated polyolefins with emulsions of the graft polymers or with an emulsion of a copolymer (according to component B), preferably on a styrene/acrylonitrile basis or polymethyl methacrylate basis, the fluorinated polyolefin being mixed as an emulsion with an emulsion of the graft polymer or copolymer and then coagulated.
The fluorinated polyolefins can further be used as a pre-compound with the graft polymer or a copolymer, preferably on a styrene/acrylonitrile or polymethyl methacrylate basis. The fluorinated polyolefins are mixed as a powder with a powder or pellets of the graft polymer or copolymer and compounded in the melt, generally at temperatures of 200 to 330°C, in conventional units such as internal mixers, extruders or twin screws.
The fluorinated polyolefins can also be used in the form of a masterbatch, which is produced by emulsion polymerisation of at least one monoethylenically unsaturated monomer in the presence of an aqueous dispersion of the fluorinated polyolefin. Preferred monomer components are styrene, acrylonitrile, methyl methacrylate and mixtures thereof. The polymer is used as a free-flowing powder after acid precipitation and subsequent drying.
The coagulates, pre-compounds or masterbatches conventionally have solids contents of fluorinated polyolefin of 5 to 95 wt.%, preferably 7 to 80 wt.%, in particular 8 to 60 wt.%. The aforementioned concentrations of component C that are used relate to the fluorinated polyolefin.
Component D
As component D the polycarbonate compositions can contain other polymers and/or polymer additives.
Examples of other polymers are in particular those that can display a synergistic action in the event of a fire by supporting the formation of a stable carbon layer. They are preferably polyphenylene oxides and sulfides, epoxy and phenolic resins, novolaks and polyethers.
Heat stabilisers, hydrolysis stabilisers, light stabilisers, flow control agents and processing aids, lubricants and release agents, UV absorbers, antioxidants, antistatics, preservatives, coupling agents, fibrous or particulate fillers and reinforcing agents, dyes, pigments, nucleating agents, impact modifiers, foaming agents, processing aids, other flame-retarding additives and agents to reduce smoke development, together with mixtures of the cited additives, can be used as possible polymer additives.
Examples of additional flame-retarding additives are particularly and preferably known phosphorus-containing compounds such as monomelic and oligomeric phosphoric and phosphonic acid esters, phosphonate amines, phosphoramidates and phosphazenes, silicones and optionally fluorinated alkyl or aryl sulfonic acid salts. Such compounds are adequately described in the patent applications cited in the prior art for this application. Furthermore, inorganic particles of all types in nanoscale form, siliceous minerals such as talc and wollastonites, inorganic borates such as zinc borate, tin compounds such as zinc stannates and zinc hydroxy
stannates and boron phosphorus oxide are particularly suitable as flame retardant synergists and smoke suppressants.
The compositions according to the invention are produced by mixing the various components A-D with the phosphorus-silicon compounds by known means and melt compounding and melt extruding them at temperatures of 200°C to 300°C in conventional units such as internal mixers, extruders and twin screws.
The individual constituents can be mixed by known means both successively and simultaneously, both at around 20°C (room temperature) and at elevated temperature.
The compositions according to the invention can be used in the production of all types of mouldings. These can be produced for example by injection moulding, extrusion and blow moulding processes. A further form of processing is the production of mouldings by thermoforming from prefabricated sheets or films.
Examples of such mouldings are films, profiles, all types of housing sections, e.g. for domestic appliances such as juice extractors, coffee machines, mixers; for office equipment such as monitors, printers, copiers; also plates, pipes, electric wiring ducts, profiles for the construction sector, interior fittings and exterior applications; parts for the electrical engineering sector such as switches and plugs and interior and exterior automotive parts.
The compositions according to the invention can in particular be used to produce the following mouldings, for example:
Interior fittings for rail vehicles, ships, aircraft, buses and cars, housings for electrical appliances containing miniature transformers, housings for equipment for information dissemination and transfer, housings and cladding for medical purposes, massage equipment and housings, two-dimensional prefabricated wall panels,
housings for safety equipment, mouldings for sanitary and bathroom equipment, and housings for gardening implements.
The following examples are intended solely to illustrate the invention in more detail.
Examples
I) Phosphorus-silicon compound
(referred to as component E3 in tables 1 and 2)
1.) Production of a phosphorylated silane
In a three-neck flask fitted with a thermometer and reflux condenser 19.6 g (158 mmol) dimethyl methane phosphonate are added dropwise at room temperature to 20.0 g (79 mmol) diphenyl dichlorosilane under an argon protective gas atmosphere. On completion of the addition the reaction mixture is stirred until no more gas (methyl chloride) escapes.
2.) Oligomerisation of the phosphorylated silane
The reaction mixture from 1) is thermally oligomerised at 150°C and the dimethyl methane phosphonate that is produced is continuously removed by distillation under a pressure of 0.08 mbar until the reaction mixture reaches a constant weight. A colourless, highly viscous liquid is produced, which solidifies to a solid, glassy substance when cooled to room temperature.
Yield: 20.7 g
Melting point: approx. 54°C
Elemental analysis: carbon 55 %, silicon 12 %, phosphorus 10 %
Thermogravimetric analysis: 4 wt.% loss of mass at 280°C, measured in a nitrogen
stream at a heating-up rate of 20 K/h
Molecular weight: Mw = 963 g/mol (measured by gel permeation chromatography
using a 260 nm DAD UV detector; quantitative analysis was performed by means of
a calibration relation valid for polysiloxanes at room temperature in
dichloromethane)
The results of the characterisation indicate that in the sum of steps 1) and 2) the reaction
(Formula Removed)
proceeded in accordance with the literature Phosphorus, Sulfur, and Silicon 68 (1992) 107-114 and substantially a product having a weight-average n value of approximately 3 was produced.
II) Polycarbonate compositions
The mixtures are produced by melt compounding on a TS/I-02 mini-extruder (DSM) at a melt temperature of 290°C (PC7ABS compositions) or 310°C (PC compositions). All specimens used are obtained by injection moulding on a TS/I-01 injection moulding machine (DSM) connected to the extruder. The mould temperature is 80°C.
Component Al
Linear polycarbonate based on bisphenol A with a relative solution viscosity of 1.28, measured in CH2Cl2 as solvent at 25°C and in a concentration of 0.5 g/100 ml.
Component A2
Linear polycarbonate based on bisphenol A with a relative solution viscosity of 1.26,
measured in CH2Cl2 as solvent at 25°C and in a concentration of 0.5 g/100 ml.
Component B
Graft polymer of 40 parts by weight of a copolymer of styrene and acrylonitrile in the ratio 73:27 on 60 parts by weight of particulate crosslinked polybutadiene rubber (average particle diameter d50 = 0.3 µm), produced by emulsion polymerisation.
Component C1
Tetrafluoroethylene polymer as a coagulated mixture of a graft polymer emulsion according to the aforementioned component B in water and a tetrafluoroethylene polymer emulsion in water. The ratio by weight of graft polymer B to the tetrafluoroethylene polymer in the mixture is 90 wt.% to 10 wt.%. The tetrafluoroethylene polymer emulsion has a solids content of 60 wt.%; the average particle diameter is between 0.05 and 0.5 urn. The graft polymer emulsion has a solids content of 34 wt.%.
The emulsion of the tetrafluoroethylene polymer (Teflon® 30 N from DuPont) is mixed with the emulsion of the graft polymer B and stabilised with 1.8 wt.%, relative to polymer solids, of phenolic antioxidants. The mixture is coagulated with an aqueous solution of MgSO4 (Epsom salts) and acetic acid at pH 4 to 5 and at a temperature of 85 to 95°C, filtered and washed until it is practically free from electrolytes, then freed from the bulk of the water by centrifuging and subsequently dried to a powder at 100°C.
Component Dl
Pentaerythritol tetrastearate (PETS) as release agent
Component D2
Phosphite stabiliser
Component El
Disflamol® TP: triphenyl phosphate supplied by Bayer AG, Leverkusen, Germany
Component E2
Silres® SY 300: silanol-functional solid phenyl propyl polysiloxane supplied by
Wacker-Chemie GmbH, Munich, Germany
Testing the properties of the moulding compositions according to the invention
The flame resistance of the compositions is evaluated in a total of three test procedures.
A first test is performed by reference to the incandescent wire test in accordance with EEC 60695-2-12. An incandescent metal wire at a temperature of 960°C is pressed for 30 s against specimens having a wall thickness of 1.5 mm and the degree of flame resistance of the composition is assessed from the maximum flame height during the period of contact with the incandescent wire and the subsequent burning time and from the burning time after removal of the incandescent wire. The test is regarded as having been passed if the burning time following removal of the incandescent wire does not exceed 30 s. Reduced maximum flame heights are taken as an indicator of improved flame resistance but have no influence on whether the test is passed.
A second test to assess the flame resistance of the compositions is performed by reference to UL-Subj. 94 V on test pieces of thickness 1.5 mm. A defined pilot flame is applied from below to vertically mounted test pieces for 10 s, the time for the flame to go out determined in order then to reapply the pilot flame for 10 s and again to determine the time for the flame to go out. This test is performed on a total of 5 test pieces. The sum of the 10 individual burning times is determined, along with the tendency of the material to drip as it burns during the test. The best rating, V-0, is given to materials that do not drip as they burn, for which the total burning time does not exceed 50 s and for which no individual burning time is longer than 10 s. The rating V-2 permits the material to drip as it burns. The test is classed as having been
failed if the total burning time for the ten individual applications of the flame exceeds 250 s or if at least one individual burning time is longer than 30 s.
A third test to assess the flame resistance of the compositions is performed by reference to the LOI test (low oxygen index) as defined in ASTM D 2863 on test pieces of wall thickness 4.0 mm, the upper end of vertically mounted specimens being ignited in a nitrogen-oxygen atmosphere having a variable O2 content and the oxygen content at which the specimen just goes out of its own accord being determined.
The tendency of volatile components to bleed during processing ("juicing") is assessed by means of a thermogravimetric analysis performed dynamically in a nitrogen stream. The loss of mass of the composition at 280°C, determined at a heating-up rate of 20 KVmin, is used as reference.
Table 1: Tests in polycarbonate

(Table Removed)
The data from Table 1 shows that pure polycarbonate can be rendered flame resistant with low-volatility phosphorus-silicon compounds. The compositions from Examples 2 to 4 provide transparent specimens, which shows the compatibility of the additive with the polymer phase. Even with such a low concentration as only 1 part by weight, clear improvements in flame resistance can be achieved with the phosphorus-silicon compound (burning time in UL94V test reduced, incandescent wire test passed and LOI increased). With an addition of 3 wt.% of the phosphorus-silicon compound a V-0 rating is even achieved in the UL94V test.
Table 2: Tests in PC/ABS blends

(Table Removed)
NP = test not passed
The data in Table 2 shows that PC/ABS blends too can be rendered flame resistant with the phosphorus-silicon compounds. V-2 ratings can be achieved in the UL94V test, and the incandescent wire test is passed. The LOI also shows a rise. When used in the same concentration, phosphoric acid esters (comparative example 8) display a poorer performance in the UL94V test and (in the case of the more efficiently fire-resistant monomeric phosphoric acid esters) greater "juicing". In the same concentration partially aromatic silicones (comparative example 9) display a poorer

performance in the UL94V test and in the incandescent wire test. When a concentration of 5 parts by weight of silicone was used, the two tests were no longer passed.





WE CLAIM:
1. A poly(ester)carbonate composition comprising at least one phosphorus-silicon compound of formula (III)
(Formula Removed)
wherein
R1 mutually independently represents hydrogen or C1-C4 alkyl,
R2 represents a member selected from the group consisting of aryl radical,
alkyl radical, arloxy radical, alkoxy radical and hydrogen and
R3 mutually independently represents a member selected from the group
consisting of alkyl radical, aryl radical and aryl radical substituted with C1-C4
alkyl.
and
m denotes 2 to 1000.
and
the polycarbonate composition containing
A) 60 to 100 parts by weight of aromatic poly(ester) carbonates,
B) 0 to 40 parts by weight of at least one polymer of the kind such as herein described selected from the group consisting of vinyl (co)polymers, rubber-modified vinyl (co)polymers and aromatic polyesters,
C) 0 to 5 parts by weight of fluorinated polyolefin and
D) up to 20 parts by weight of other polymers and/or conventional polymer additives,
the parts by weight of components A to D totaling 100,
wherein the said poly(ester)carbonate composition containing 0.05 to 30 parts by weight of the phosphorus-silicon compounds, relative to 100 parts by weight of a polycarbonate composition.
2. Composition as claimed in claim 1, wherein containing 0.1 to 20 parts by
weight of phosphorus-silicon compounds.
3. Composition as claimed in claim 1, wherein containing 1.5 to 8 parts by
weight of phosphorus-silicon compounds.
4. Composition as claimed in claim 1, wherein component B) is a graft
polymer of
B. 1 5 to 95wt. % of monomers of a mixture comprising 50 to 99 wt.% of at least one selected from the group of vinyl aromatics, ring-substituted vinyl aromatics and methacrylic acid (C1-C8) alkyl esters and 1 to 50 wt.% of at least one selected from the group of vinyl cyanides, (meth)acrylic acid (Ci-Cs) alkyl esters and derivatives of unsaturated carboxylic acids on
B.2 95 to 5 wt.% of one or more rubbers having glass transition temperatures 5. Composition as claimed in claim 4, wherein as monomer mixture B. 1
contains 10 to 90 wt.% of at least one monomer selected from the group
comprising styrene, a-methyl styrene and methyl methacrylate and 90 to 10
wt.% of at least one monomer selected from the group comprising acrylonitrile,
maleic anhydride and methyl methacrylate.
6. Composition as claimed in claim 4, wherein the graft base B.2 is selected
from the group comprising diene rubbers, EP(D)M rubbers, acrylate rubbers,
silicone rubbers and silicone-acrylate composite rubbers or a mixture of at
least two of the aforementioned rubbers.
7. Composition as claimed in claim 1, containing vinyl (co)polymers
comprising 50 to 99 wt.% of at least one monomer selected from styrene, α-
methyl styrene, p-methyl styrene, p-chlorostyrene and methacrylic acid (C1 to
C8)alkyl ester, and 1 to 50 wt.% of at least one monomer selected from
acrylonitrile, methacrylonitrile and (meth)acrylic acid, (C1-C8) alkyl ester.
8. Composition as claimed in claim 1, wherein additives selected from at
least one of the group comprising heat stabilisers, hydrolysis stabilisers, light
stabilisers, flow control agents and processing aids, lubricants and release
agents, UV absorbers, antioxidants, antistatics, preservatives, coupling agents,
fibrous or particulate fillers and reinforcing agents, dyes, pigments, nucleating
agents, foaming agents, processing aids, other flame-retarding additives and agents to reduce smoke development.
9. Mouldings obtainable from a composition as claimed in claim 1. Dated this on

Documents:

2048-delnp-2005-abstract.pdf

2048-delnp-2005-claims.pdf

2048-delnp-2005-complete specification(as filed).pdf

2048-delnp-2005-complete specification(granted).pdf

2048-delnp-2005-correspondence-others.pdf

2048-delnp-2005-correspondence-po.pdf

2048-delnp-2005-description (complete).pdf

2048-delnp-2005-form-1.pdf

2048-delnp-2005-form-13.pdf

2048-delnp-2005-form-18.pdf

2048-delnp-2005-form-2.pdf

2048-delnp-2005-form-3.pdf

2048-delnp-2005-form-5.pdf

2048-delnp-2005-gpa.pdf

2048-delnp-2005-pct-210.pdf

2048-delnp-2005-pct-304.pdf

2048-delnp-2005-pct-306.pdf

2048-delnp-2005-petition-137.pdf

2048-delnp-2005-petition-138.pdf


Patent Number 246353
Indian Patent Application Number 2048/DELNP/2005
PG Journal Number 09/2011
Publication Date 04-Mar-2011
Grant Date 25-Feb-2011
Date of Filing 13-May-2005
Name of Patentee BAYER MATERIALSCIENCE AG
Applicant Address 51368 LEVERKUSEN,GERMANY.
Inventors:
# Inventor's Name Inventor's Address
1 ANDREAS SEIDEL BIRNENWEG 5,D-41542 DORMAGEN,GERMANY.
2 MICHAEL WAGNER MOERSER HEIDE 68,D-47443,MOERS,GERMANY.
3 JOCHEN ENDTNER JAKOB-BOHME-STR. 4,D-51065,KOLN,GERMANY.
4 WOLFGANG EBENBECK CARL-RUMPFF-STR. 9,51373 LEVERKUSEN,GERMANY.
5 THOMAS ECKEL PFAUENSTR. 51,D-41540 DORMAGEN,GERMANY
6 DIETER WITTMANN ERNST-LUDWIG-KIRCHNER-STR. D-51375 LEVERKUSEN,GERMANY.
PCT International Classification Number C08L 69/00
PCT International Application Number PCT/EP2003/013151
PCT International Filing date 2003-11-22
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 DE 102 57 081.7 2002-12-06 Germany