The invention relates to a polymer mixture which comprises an aromatic polycarbonate, a styrene-containing copolymer and/or a styrene-containing graft polymer and a flame-retardant. It has been found that the use of a certain type of flame-retardants, namely oligomeric phosphates leads to a polymer mixture having improved properties. In particular to a polymer mixture having a good combination of flame retardancy, non-juicing characteristics of the flame retardant, good plastifying effect and good heat resistance.
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1. A polymer mixture which comprises an aromatic polycarbonate (A), a styrene-containing copolymer and/or styrene-containing graft copolymer (B) and a phosphate based flame-retardant (C), characterized in that the polymer mixture comprises as flame-retardant an oligomeric phosphate or a blend of oligomeric phosphates with the following formula I: ##STR3## wherein R1, R2, R3, and R4, each represent an aryl or an alkaryl group chosen independently of each other with the proviso that none of R1, R2, R3 and R4 are xylyl and wherein X is an arylene group, m1, m2, m3, and m4, each independently of each other are 0 or 1 and wherein n=1,2,3,4 or 5 or wherein, in case of a blend of phosphates, n has an average value of 1 to 5.
2. A polymer mixture as claimed in
smaller than 2.4. A polymer mixture as claimed in claim 1, characterized in that the polymer comprises an oligomeric phosphate of formula 1, or a blend of such phosphates, which comprises an aromatic polycarbonate (A), a styrene-containing copolymer and/or styrene-containing graft copolymer (B) and a phosphate based flame-retardant (C), characterized in that the polymer mixture comprises as flame-retardant a blend of oligomeric phosphates with the following formula I: ##STR4## wherein m1, m2, m3 and m4 are all equal to 1, R1, R2, R3 and R4 all represent a phenyl group, X represents a phenylene group and n has an (average) value of 1,2-1.7 1.2-1.7. 5. A polymer mixture according to claim 1 4, characterized in that the mixture comprises 5-95% by weight of constituent A and 95-5% by weight of constituent B, calculated with respect to the sum of the quantities of A and B. 6. A polymer mixture according to claim 1 4, characterized in that the mixture comprises as constituent B a graft copolymer built up from a rubber backbone upon which have been grafted styrene, alphamethylstyrene, a styrene substituted with one or more halogen atoms or with organic groups in its aromatic nucleus, methylmethacrylate or a blend thereof and acrylonitrile, methacrylonitrile, methylmethacrylate, maleic anhydride, N-substituted maleinimide maleimide or a blend thereof. 7. A polymer mixture according to claim 1 characterised 4 characterized in that the mixture comprises as constituent B a copolymer of styrene, alpha-methylstyrene, a styrene substituted with one or more halogen atoms or with organic groups in its aromatic nucleus, methylmethacrylate or a blend thereof and acrylonitrile, methacrylonitrile, methylmethacrylate, maleic anhydride, N-substituted maleinimid maleimide or a blend thereof. 8. A polymer mixture according to claim 1 4, characterized in that the mixture comprises as constituent B a graft copolymer built up from a rubber backbone upon which have been grafted styrene, alphamethylstyrene, a styrene substituted with one or more halogen atoms or with organic groups in its aromatic nucleus, methylmethacrylate or a blend thereof and acrylonitrile, methacrylonitrile, methylmethacrylate, maleic anhydride, N-substituted maleinimide maleimide or a blend thereof and a copolymer of styrene, alphamethylstyrene, a styrene substituted with one or more halogen atoms or with organic groups in its aromatic nucleus, methylmethacrylate or a blend thereof and acrylonitrile, methacrylonitrile, methylmethacrylate, maleic anhydride, N-substituted maleinimide maleimide or a blend thereof. 9. A polymer mixture according to claim 1 4, characterized in that the mixture comprises 1-25 parts by weight of constituent C per 100 part by weight of A+B. 10. A polymer mixture according to claim 1 4, characterized in that the mixture comprises 5-20 parts by weight of constituent C per 100 parts by weight of A+B. 11. A polymer mixture as claimed in claim 1 4, characterised characterized in that the polymer mixture moreover comprises one or more of the following flame retardants (D): a salt having flame-retarding properties for aromatic polycarbonates and/or a halogen-containing low-molecular weight compound and/or high-molecular weight polymer and/or a perfluoroalkane polymer and/or a metal compound active as a synergist. 12. A polymer mixture as claimed in claim 1 4, characterized in that the polymer mixture comprises the oligomeric phosphate (C) in combination with a salt having flame-retarding properties for aromatic polycarbonate. 13. A polymer mixture as claimed in claim 1 4, characterised characterized in that the polymer mixture moreover comprises a perfluoroalkane polymer. 14. Articles formed from the polymer mixture as claimed in claim 1 4. 15. A polymer mixture which comprises an aromatic polycarbonate (A), a styrene-containing copolymer and/or styrene-containing graft copolymer (B) and a phosphate based flame-retardant (C), characterized in that the polymer mixture comprises as flame-retardant a blend of oligomeric phosphates with the following formula I: ##STR5## wherein R1, R2, R3 and R4 each represent an aryl or an alkaryl group chosen independently of each other with the proviso that none of R1, R2, R3 and R4 are xylyl and wherein X is an arylene group, m1, m2, m3 and m4 each independently of each other are 0 or 1 and wherein n has an average value of 1.2-1.7. 16. A polymer mixture according to claim 15, characterized in that the mixture comprises 5-95% by weight of constituent A and 95-5% by weight of constituent B, calculated with respect to the sum of the quantities of A and B. 17. A polymer mixture according to claim 15, characterized in that the mixture comprises as constituent B a graft copolymer built up from a rubber backbone upon which have been grafted styrene, alphamethylstyrene, a styrene substituted with one or more halogen atoms or with organic groups in its aromatic nucleus, methylmethacrylate or a blend thereof and acrylonitrile, methacrylonitrile, methylmethacrylate, maleic anhydride, N-substituted maleimide or a blend thereof. 18. A polymer mixture according to claim 15 characterized in that the mixture comprises as constituent B a copolymer of styrene, alpha-methylstyrene, a styrene substituted with one or more halogen atoms or with organic groups in its aromatic nucleus, methylmethacrylate or a blend thereof and acrylonitrile, methacrylonitrile, methylmethacrylate, maleic anhydride, N-substituted maleimide or a blend thereof. 19. A polymer mixture according to claim 15, characterized in that the mixture comprises as constituent B a graft copolymer built up from a rubber backbone upon which have been grafted styrene, alphamethylstyrene, a styrene substituted with one or more halogen atoms or with organic groups in its aromatic nucleus, methylmethacrylate or a blend thereof and acrylonitrile, methacrylonitrile, methylmethacrylate, maleic anhydride, N-substituted maleimide or a blend thereof and a copolymer of styrene, alphamethylstyrene, a styrene substituted with one or more halogen atoms or with organic groups in its aromatic nucleus, methylmethacrylate or a blend thereof and acrylonitrile, methacrylonitrile, methylmethacrylate, maleic anhydride, N-substituted maleimide or a blend thereof. 20. A polymer mixture according to claim 15, characterized in that the mixture comprises 1-25 parts by weight of constituent C per 100 part by weight of A+B. 21. A polymer mixture according to claim 15, characterized in that the mixture comprises 5-20 parts by weight of constituent C per 100 parts by weight of A+B. 22. A polymer mixture as claimed in claim 15, characterized in that the polymer mixture moreover comprises one or more of the following flame retardants (D): a salt having flame-retarding properties for aromatic polycarbonates and/or a halogen-containing low-molecular weight compound and/or high-molecular weight polymer and/or a perfluoroalkane polymer and/or a metal compound active as a synergist. 23. A polymer mixture as claimed in claim 15, characterized in that the polymer mixture comprises the oligomeric phosphate (C) in combination with a salt having flame-retarding properties for aromatic polycarbonate. 24. A polymer mixture as claimed in claim 15, characterized in that the polymer mixture moreover comprises a perfluoroalkane polymer. 25. Articles formed from the polymer mixture as claimed in claim 15. |
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This is a continuation of copending application Ser. No. 07/750,703, filed Aug. 20, alkarylgroupseperate separate compounds or in the form of a blend of several different oligomers. The value of n in formula 1 is by preference greater than 0 but smaller than 3, more by preference equal to or greater than 1, but equal to or smaller than 2.
In the case of a blend of several different oligomers the above mentioned values for n indicate the average value in the oligomer blend.
The aryl groups R1, R2, R3 and R4 may be substituted with halogen atoms or alkyl groups. The aryl group preferably is a cresyl group and/or phenyl group and/or xylenyl group and/or is a propylphenyl group and/or butylphenyl group and/or a brominated or chlorinated derivate derivative thereof. The arylene group is a group derived from a dihydric compound, for example, resorcinol, hydroquinone, bisphenol A and chlorides and bromides thereof. These compounds are known per se.
A mixture of these oligomeric phosphates can be readily used, each having a different value of n.
The preferably used oligomeric phosphate is an oligomeric phosphate of formula 1, or a blend of such phosphates, wherein m1, m2, m3 and m4 are all equal to 1, R1, R2, R3 and R4 all represent a phenyl group. X represents a phenylene group and n has an (average) value of 1.2 to 1.7.
In addition to the above phosphates or phosphonates the polymer mixture according to the invention may comprise further agents to improve the flame-retarding properties. In particular may be mentioned:
a salt having flame-retarding properties for aromatic polycarbonates
a halogen-containing low-molecular weight compound and/or high-molecular weight polymer and/or
a perfluoroalkane polymer and/or
a metal compound active as a synergist.
Salts having flame-retarding properties are generally known and are used on a large scale in polymer mixtures which comprise a polycarbonate. All salts which are suitable for polymer mixtures having a polycarbonate may be used in the polymer mixture according to the invention. In particular may be mentioned organic and inorganic sulphonates sulfonates, for example, sodium trichlorobenzene sulphonate sulfonate, salts of sulphone sulphonates sulfone sulfonates, for example, the potassium salt of diphenylsulphone sulphonate diphenylsulfone sulfonate, salts of perfluorinated alkane sulphonic sulfonic acid and sodium aluminium aluminum hexafluoride.
Examples of suitable halogen-containing compounds are decabromodiphenyl ether, octabromodiphenyl, octabromodiphenyl ether and further oligomeric or polymeric bromine compounds, for example, derived from tetrabromobisphenol A or also polyphenylene ethers brominated in the nucleus.
The salts mentioned hereinbefore are to be preferred. The addition of particularly small quantities from 0.01-0.5 parts by weight already provides a strongly noticeable effect.
Tetrafluoroethylene polymers are preferably used as perfluoroalkane polymers. The polymer mixture according to the invention may further comprise a metal or metal compound active as a synergist, for example, antimony oxide and the like. These synergists are usually used in combination with halogen-containing compounds.
In addition to the constituents mentioned hereinbefore the polymer mixture according to the invention may comprise one or more conventional additives, for example, fillers, reinforcing fibres fibers, stabilisers stabilizers, pigments and dyes, plasticisers plasticizers, mould mold release agents and antistatically active agents.
The polymer mixture can be obtained according to the conventional techniques of preparing polymer mixtures, for example, by compounding the said constituents in an extruder.
The polymer mixture according to the invention preferably comprises the said constituents in the following relative quantities:
Per 100 parts by weight of constituents A+B the polymer mixture according to the invention may comprise
D. 0-20 parts by weight of one or more further agents to improve the flame-retarding properties and or
E. 0-100 parts by weight of conventional additives.
The following constituents were used in the examples hereinafter:
| ______________________________________ |
| PC-1 an aromatic polycarbonate derived from |
| bisphenol A and phosgene having an |
| intrinsic viscosity of 49 ml/g measured |
| in methylene chloride at 25°C |
| PC-2 an aromatic polycarbonate having an |
| intrinsic viscosity of 55 ml/g. |
| ABS-1 a graft copolymer, built up |
| substantially from a butadiene rubber on |
| which styrene and acrylonitrile have |
| been grafted, with a rubber-content of |
| approximately 30%. |
| ABS-2 a graft copolymer built up substantially |
| from a butadiene rubber on which styrene |
| and acrylonitrile have been grafted with |
| a rubber content of approximately 70%. |
| ABS-3 a similar product as ABS-1 and ABS-2 |
| with a rubber content of approximately |
| 50%. |
| Phosphate-1 a mixture of several oligomeric |
| phosphates with formula 1, wherein R1, |
| R2, R3 and R4 represent a phenyl-group, |
| m1, m2, m3 and m4 are all 1, X is a |
| phenylene group and n has an average |
| value of about 1.4. |
| Phosphate-2 a mixture of several oligomeric |
| phosphates with the same structure as |
| phosphate-1, but with an average value |
| of n of approximateiy 2.8. |
| TPP-1 triphenyl phosphate |
| TPP-2 a 40/60 blend of triphenylphosphate and |
| trisisopropylphenylphosphate. |
| BR-PC a polymeric polycarbonate having units |
| derived from tetrabromobisphenol A and |
| from bisphenol A, with a bromine content |
| of about 25%. |
| Teflon ® a tetrafluoropolyethylene |
| STB the sodium salt of trichlorobenzene |
| sulphonate sulfonate. |
| SAN a styrene-acrylonitrile copolymer with a |
| molecular weight of about 100,000 and a |
| styrene to acrylonitrile ratio of about |
| 72 to 28. |
| ______________________________________ |
Four different polymer mixtures were prepared from the above-mentioned constituents in the quantities as indicated in the following table. For that purpose the indicated constituents were compounded in an extruder. The resulting extrudate was then pelletised pelletized. Standardised Standardized test rods were injection-moulded injection molded from the pellets to determine the properties. The properties found are also recorded in the following table A:
| TABLE A |
| ______________________________________ |
| Example No. A B I II III |
| ______________________________________ |
| Composition |
| (parts by weight) |
| PC-1 75 64.5 64.5 64.5 58.5 |
| ABS-1 25 25 25 25 25 |
| Phosphate-1 -- -- 10 10 10 |
| TPP-1 -- 10 -- -- -- |
| Teflon -- 0.5 0.5 0.5 0.5 |
| STB -- 0.02 -- 0.02 -- |
| Br.PC -- -- -- -- 6 |
| Properties |
| UL-rating1) |
| HB V-1 V-2 V-0 V-0 |
| (1.6 mm) |
| Vicat2) (°C.) |
| 133 89 95 95 96 |
| Juicing3) |
| + - + + + |
| ______________________________________ |
| 1) The ULrating has been determined according to Underwriters |
| Laboratory. (UL94) |
| 2) Determined according to ASTM D1525, |
| 3) Juicing: |
| + = no deposition of phosphates on the surface |
| - = deposition of phosphates on the surface. |
It may be seen from the above results that polycarbonate/ABS mixtures have a reasonable heat distortion temperature (Vicat value). The addition of a phosphate leads to a considerable reduction thereof (compare examples A and B). The polymer mixture according to the invention (examples I, II and III) has a more favourable favorable Vicat value as compared to example B. The polymer mixture according to Example I has a reasonable flame-extinction (V-2). A considerable improvement of the flame-retarding properties (V-0) occurs by the addition of an extremely small quantity of salt (example II). This effect occurs to a far lesser extent when the same salt is used in combination with triphenyl phosphate (TPP) (example B). In order to obtain a rating V-0 it is possible to use the phosphate in combination with a bromine compound (example III).
As shown in the following examples it is possible to obtain a V-0 rating by using the oligomeric phosphate alone or in combination with a halogenated containing flame retardant.
Polymer mixtures with a composition as shown in table B were prepared by compounding in an extruder. The measured properties are also recorded in table B.
| TABLE B |
| ______________________________________ |
| Example No. |
| IV C V D |
| ______________________________________ |
| Composition |
| (parts by weight) |
| PC-1 -- -- 79 79 |
| PC-2 68 68 -- -- |
| ABS-2 -- -- 9 9 |
| ABS-3 10 10 -- -- |
| SAN 15 15 -- -- |
| Phosphate-1 |
| 7 -- 12 -- |
| TPP-2 -- 7 -- 12 |
| Br.PC 10 10 -- -- |
| Teflon 0.3 0.3 0.2 0.2 |
| Properties |
| UL94 rating at |
| V-0 V-0 V-0 V-0 |
| 1.6 mm(1) |
| Vicat(2) (°C.) |
| 114 108 98 92 |
| Juicing(3) |
| not tested not tested + - |
| ______________________________________ |
| (1), (2), (3) see notes under Table A. |
As can be seen it is possible (example V) to obtain a V-0 rating with the oligomeric phosphates, at a relatively low content (12 parts by weight). In case a higher vicat Vicat temperature is required one may use a lower concentration of the oligomeric phosphate in combination with a bromine flame retardant (example IV). The oligomeric phosphate does not cause juicing at the concentrations required for obtaining a V-0 rating.
| TABLE C |
| __________________________________________________________________________ |
| Examples VI-XIII and E, F |
| Several other polymer mixtures were prepared. Their |
| composition and their properties are shown in Table C here below. |
| Example V VI VII |
| VIII |
| E F IX X XI XII |
| XIII |
| __________________________________________________________________________ |
| Composition |
| (parts by weight) |
| PC-1 79 77 63 -- 80 -- -- -- -- 79 78 |
| PC-2 -- -- -- 60 -- 70 78 85 55 -- -- |
| ABS-2 9 -- -- -- 9 -- -- -- -- 9 9 |
| ABS-3 -- 12 12 12 -- 9 9 5 10 -- -- |
| SAN -- -- 15 15 -- 10 3 -- 15 -- -- |
| Phosphate-1 |
| 12 11 10 13 -- -- 10 10 10 12 13 |
| TPP-2 -- -- -- -- 11 11 -- -- -- -- -- |
| Br-PC -- -- -- -- -- -- -- -- 10 -- -- |
| Teflon 0.2 |
| 0.2 |
| 0.2 |
| 0.2 |
| 0.2 |
| 0.2 |
| 0.2 |
| 0.2 |
| 0.5 |
| -- -- |
| Eigenschappen |
| Properties |
| UL-94, 1.6 mm |
| V-0 |
| V-0 |
| V-0 |
| V-0 |
| V-0 |
| V-0 |
| V-0 |
| V-0 |
| V-0 |
| V-2 |
| V-2 |
| Total flame |
| 15 20 30 20 35 25 27 22 15 25 20 |
| out time |
| (sec) |
| Burning drips |
| no no no no no no no no no yes |
| yes |
| Vicat (°C.) |
| 98 99 100 |
| 92 91 90 108 |
| 108 |
| 108 |
| 98 95 |
| Juicing + + + + - - + + + + + |
| Tensile 10 10 7 7 6.5 |
| 4 |
| elongation |
| at weld |
| line (%) |
| Unnotched 800 |
| 759 |
| 300 |
| 350 |
| 35C |
| 150 |
| Izod impact |
| at weld line |
| __________________________________________________________________________ |
In table C the composition and the properties of the polymer mixture according to example V have also been listed. A test piece was prepared out of the polymer mixtures according to examples V-VIII and E and F by means of injection moulding molding with a double gate.At gate. At the weld line the elongation and the unnotched Izod impact were determined. By comparing Example F (comparative example) with example VIII and by comparing example E (comparative example) with example V one can easily see that the polymer mixture according to the invention shows an improved weld line strength due to the presence of an oligomeric phosphate instead of a monophosphate.
Three more examples were prepared, corresponding in composition with example V with the exception of the used phosphates. The used phospates phosphates and the properties are recorded in tabel table D herebelow.
| TABLE D |
| ______________________________________ |
| Example XVI XIV |
| XVII XV |
| G |
| ______________________________________ |
| Phosphate used |
| phosphate-1 phosphate-2 |
| TPP-1 |
| Properties |
| UL-94, 1.6 mm |
| V-0 HB V-0 |
| average flame |
| 1-6 14-16 1-7 |
| out time (sec) |
| Maximum single |
| 7 60 9 |
| flame out time |
| (sec) |
| Melt viscosity at |
| 250°C for different |
| shear rates: |
| 115 per sec. 450 653 300 |
| 1150 per sec. |
| 230 319 185 |
| 2300 per sec. |
| 181 250 160 |
| Juicing + + - |
| Vicat (°C.) |
| 98 115 85 |
| ______________________________________ |
As can be seen from the results of table D the flame retardant properties of the oligomeric phosphates decrease rapidly upon increasing the average value of n from 1.4 (phosphate-1) to 2.8 (phosphate-2). The plasticizing effect also decreases dramatically.
Pratt, Charles F., Gosens, Johannes C., Savenije, Herman B., Claesen, Christianus A. A.
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