U.S. patent number RE36,902 [Application Number 09/405,635] was granted by the patent office on 2000-10-03 for flame resistant polycarbonate/abs moulding compounds resistant to stress cracking.
This patent grant is currently assigned to Bayer AG. Invention is credited to Heinrich Alberts, Thomas Eckel, Manfred Oller, Dieter Wittmann.
United States Patent |
RE36,902 |
Eckel , et al. |
October 3, 2000 |
Flame resistant polycarbonate/abs moulding compounds resistant to
stress cracking
Abstract
Flame resistant, thermoplastic molding compounds containing A)
40 to 98 parts by weight of an aromatic polycarbonate, B) 3 to 50
parts by weight of a vinyl copolymer, C) 0.5 to 40 parts by weight
of a graft polymer, D) 0.5 to 20 parts by weight of a mixture of
D.1) 10 to 90 wt. %, related to D) , of a monophosphorus compound
of the formula (I) ##STR1## D.2) 90 to 10 wt. %, related to D), of
an oligomeric phosphorus compound of the formula (II) ##STR2## and
E) 0.05 to 5 parts by weight of a fluorinated polyolefin with an
average particle diameter of 0.05 to 1000 .mu.m, a density of 1.2
to 2.3 g/cm.sup.3 and a fluorine content of 65 to 76 wt. %.
Inventors: |
Eckel; Thomas (Dormagen,
DE), Wittmann; Dieter (Leverkusen, DE),
Oller; Manfred (Krefeld, DE), Alberts; Heinrich
(Odenthal, DE) |
Assignee: |
Bayer AG (Leverkusen,
DE)
|
Family
ID: |
6496038 |
Appl.
No.: |
09/405,635 |
Filed: |
September 27, 1999 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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516899 |
Aug 18, 1995 |
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290544 |
Aug 15, 1994 |
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Reissue of: |
764747 |
Dec 12, 1996 |
05672645 |
Sep 30, 1997 |
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Foreign Application Priority Data
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Aug 26, 1993 [DE] |
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43 28 656 |
|
Current U.S.
Class: |
524/127;
524/145 |
Current CPC
Class: |
C08K
5/523 (20130101); C08L 69/00 (20130101); C08K
5/523 (20130101); C08L 69/00 (20130101); C08L
69/00 (20130101); C08L 25/02 (20130101); C08L
27/12 (20130101); C08L 27/18 (20130101); C08L
33/06 (20130101); C08L 51/04 (20130101); C08L
85/02 (20130101); C08L 2666/02 (20130101) |
Current International
Class: |
C08L
69/00 (20060101); C08L 25/00 (20060101); C08L
27/18 (20060101); C08L 27/00 (20060101); C08L
33/00 (20060101); C08L 51/00 (20060101); C08L
25/02 (20060101); C08L 33/06 (20060101); C08L
51/04 (20060101); C08K 005/523 () |
Field of
Search: |
;524/145,127 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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521 745 |
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0000 |
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EP |
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174 493 |
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Mar 1986 |
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EP |
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363 608 |
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Apr 1990 |
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EP |
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491 986 |
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Jul 1992 |
|
EP |
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594 021 |
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Apr 1994 |
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EP |
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521 628 |
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Mar 1996 |
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EP |
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59-024736 |
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Feb 1984 |
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JP |
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59-045351 |
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Mar 1984 |
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JP |
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Other References
Abstract of JA 59 202 240, cited in Polymer and General Chemistry,
p. 2..
|
Primary Examiner: Hoke; Veronica P.
Attorney, Agent or Firm: Connolly Bove Lodge & Hutz
LLP
Parent Case Text
This application is a continuation of application Ser. No.
08/516,899 filed on Aug. 18, 1995 now abandoned, which in turn is a
continuation of Ser. No. 08/290,544, filed on Aug. 15, 1994 now
abandoned.
Claims
We claim:
1. Flame resistant, thermoplastic moulding compounds containing
A) 40 to 98 parts by weight of an aromatic polycarbonate;
B) 3 to 50 parts by weight of a vinyl copolymer prepared from
B.1) 50 to 98 parts by weight of styrene, .alpha.-methylstyrene,
ring-substituted styrenes, C.sub.1 -C.sub.8 alkyl methacrylates,
C.sub.1 -C.sub.8 alkyl acrylates or mixtures thereof and
B.2) 50 to 2 parts by weight of acrylonitrile, methacrylonitrile,
C.sub.1 -C.sub.8 alkyl methacrylates, C.sub.1 -C.sub.8 alkyl
acrylates, maleic anhydride, N-substituted maleimides and mixtures
thereof;
C) 0.5 to 40 parts by weight of a graft polymer prepared from
C.1) 5 to 95 parts by weight of a mixture of
C.1.1) 50 to 95 parts by weight of styrene, .alpha.-methylstyrene,
halogen or methyl ring-substituted styrene, C.sub.1 -C.sub.8 alkyl
methacrylate, C.sub.1 -C.sub.8 alkyl acrylate, or mixtures of these
compounds and
C.1.2) 5 to 50 parts by weight of acrylonitrile, methacrylonitrile,
C.sub.1 -C.sub.8 alkyl methacrylates, C.sub.1 -C.sub.8 alkyl
acrylate, maleic anhydride, C.sub.1 -C.sub.4 alkyl or phenyl
N-substituted maleimides or mixtures of these compounds on
C.2) 5 to 95 parts by weight of a polymer with a glass transition
temperature of below -10.degree. C.
D) 0.5 to 20 parts by weight of a mixture of
D.1) 14 to 40 wt. %, related to D), of a monophosphorus compound of
the formula (I) ##STR9## in which R.sup.1, R.sup.2 and R.sup.3 are
independently phenyl, cresyl, cumyl, naphthyl, chlorophenyl,
bromophenyl, pentachlorophenyl or pentabromophenyl
n means 1 and
D.2) 86 to 60 wt. %, related to D), of an oligomeric phosphorus
compound of the formula (II) ##STR10## in which R.sup.4, R.sup.5,
R.sup.6, R.sup.7 are independently cresyl, phenyl xylenyl ,
propylphenyl or butylphenyl, or brominated or chlorinated
derivatives thereof,
n means 1,
y has an average value of between 1 and 2, and
x means a residue derived from resorcinol or hydroquinone, and
E) 0.05 to 5 parts by weight of a fluorinated polyolefin with an
average particle diameter of 0.05 to 1000 .mu.m, a density of 1.2
to 2.3 g/cm.sup.3 and a fluorine content of 65 to 76 wt. %.
2. Moulding compounds according to claim 1, containing 50 to 95
parts by weight of an aromatic polycarbonate A.
3. Moulding compounds as according to claim 1 containing component
D) in amounts of monophosphorus compound D.1) and an oligomeric
phosphorus compound D.2) in combined amounts effective to improve
stress cracking resistance.
4. Flame resistant thermoplastic moulding compound according to
claim 1 containing additives selected from the group consisting of
stabilizers, dyes, pigments, lubricants and mold release agents,
fillers and reinforcing materials, nucleating agents and antistatic
agents.
5. The flame resistant, thermoplastic molding compound of claim 1,
wherein in component D.2. each of R.sup.4, R.sup.5, R.sup.6 and
R.sup.7 are phenyl.
6. A flame resistant thermoplastic molding compound having improved
stress resistance, consisting essentially of:
A) 40-98 parts by weight of aromatic polycarbonate;
B) 3-50 parts by weight of styrene/acrylonitrile copolymer;
C) 0.5 to 40 parts by weight of a graft polymer of styrene and
acrylonitrile on particulate, crosslinked polybutadiene rubber;
D) 0.5 to 20 parts by weight of a mixture of:
D.1.) 14 to 40%, based on D), of triphenyl phosphate;
D.2.) 86 to 60%, based on D), of
m-phenylene-bis(diphenylphosphate); and
E) 0.05 to 5 parts by weight of tetrafluoroethylene polymer.
7. The molding compound of claim 6 containing 50 to 95 parts of A),
5 to 40 parts of B), 2 to 12 parts of C), 2 to 15 parts of D), and
0.1 to 0.5 parts of E).
8. The molding compound of claim 7, containing 67 parts of A), 10
parts of B), 7.5 parts of C), and 3.5 parts of E).
9. Flame resistant, thermoplastic moulding compounds containing
A) 40 to 98 parts by weight of an aromatic polycarbonate;
B) 3 to 50 parts by weight of a vinyl copolymer prepared from
B.1) 50 to 98 parts by weight of styrene, .alpha.-methylstyrene,
ring-substituted styrenes, C.sub.1 -C.sub.8 alkyl methacrylates,
C.sub.1 -C.sub.8 alkyl acrylates or mixtures thereof and
B.2) 50 to 2 parts by weight of acrylonitrile, methacrylonitrile,
C.sub.1 -C.sub.8 alkyl methacrylates, C.sub.1 -C.sub.8 alkyl
acrylates, maleic anhydride, N-substituted maleimides and mixtures
thereof;
C) 0.5 to 40 parts by weight of a graft polymer prepared from
C.1) 5 to 95 parts by weight of a mixture of
C.1.1.) 50 to 95 parts by weight of styrene, .alpha.-methylstyrene,
halogen or methyl ring-substituted styrene, C.sub.1 -C.sub.8 alkyl
methacrylate C.sub.1 -C.sub.8 alkyl acrylate, or mixtures of these
compounds and
C.1.2.) 5 to 50 parts by weight of acrylonitrile,
methacrylonitrile, C.sub.1 -C.sub.8 alkyl methacrylates C.sub.1
-C.sub.8 alkyl acrylate, maleic anhydride, C.sub.1 -C.sub.4 alkyl
or phenyl N-substituted maleimides or mixtures of these compounds
on
C.2) 5 to 95 parts by weight of a polymer with a glass transition
temperature of below -10.degree. C.
D) 0.5 to 20 parts by weight of a mixture of
D.1) 10 to 90 wt. %, related to D), of a monophosphorus compound of
the formula (I) ##STR11## in which R.sup.1, R.sup.2 and R.sup.3
mutually independently mean optionally halogenated C.sub.1 -C.sub.8
alkyl, C.sub.6 -C.sub.20 aryl or C.sub.7 -C.sub.12 aralkyl
n means 1 and
D.2) 90 to 10 wt. %, related to D), of an oligomeric phosphorus
compound of the formula (II) ##STR12## in which R.sup.4, R.sup.5,
R.sup.6, R.sup.7 are mutually independently cresyl, phenyl,
xylenyl, propylphenyl or butylphenyl, or brominated or chlorinated
derivatives thereof
n means 1,
Y means an average value of between 1 and 2, and
X means a residue derived from resorcinol or hydroquinone, and
E) 0.05 to 5 parts by weight of a fluorinated polyolefin with an
average particle diameter of 0.05 to 1000 .mu.m, a density of 1.2
to 2.3 g/cm.sup.3 and a fluorine content of 65 to 76 wt. %.
10. The moulding compound of claim 9, wherein component C) is one
or more of polybutadiene, butadiene styrene copolymer, acrylate
rubber, polyisobutadiene, or polyisoprene.
11. The moulding composition of claim 9, wherein component C) is
polybutadiene, butadiene/styrene copolymer, or mixtures thereof.
.Iadd.
12. Flame resistant, thermoplastic moulding compounds
containing
A) 40 to 98 parts by weight of an aromatic polycarbonate;
B) 3 to 50 parts by weight of a vinyl copolymer prepared from
B.1) 50 to 98 parts by weight of styrene, .alpha.-methylstyrene,
ring-substituted styrenes, C.sub.1 -C.sub.8 alkyl methacrylates,
C.sub.1 -C.sub.8 alkyl acrylates or mixtures thereof and
B.2) 50 to 2 parts by weight of acrylonitrile, methacrylonitrile,
C.sub.1 -C.sub.8 alkyl methacrylates, C.sub.1 -C.sub.8 alkyl
acrylates, maleic anhydride, N-substituted maleimides and mixtures
thereof;
C) 0.5 to 40 parts by weight of a graft polymer prepared from
C.1) 5 to 95 parts by weight of a mixture of
C.1.1) 50 to 95 parts by weight of styrene, .alpha.-methylstyrene,
halogen or methyl ring-substituted styrene, C.sub.1 -C.sub.8 alkyl
methacrylate, C.sub.1 -C.sub.8 alkyl acrylate, or mixtures of these
compounds and
C.1.2) 5 to 50 parts by weight of acrylonitrile, methacrylonitrile,
C.sub.1 -C.sub.8 alkyl methacrylates, C.sub.1 -C.sub.8 alkyl
acrylate, maleic anhydride, C.sub.1 -C.sub.4 alkyl alkyl or phenyl
N-substituted maleimides or mixtures of these compounds on
C.2) 5 to 95 parts by weight of a polymer with a glass transition
temperature of below -10.degree. C.,
D) 0.5 to 20 parts by weight of a mixture of
D.1) 10 to 90 wt. %, related to D), of a monophosphorus compound of
the formula (I) ##STR13## in which R.sup.1, R.sup.2 and R.sup.3
mutually independently mean optionally halogenated C.sub.1 -C.sub.8
alkyl, C.sub.6 -C.sub.20 aryl or C.sub.7 -C.sub.12 aralkyl
n means 1 and
D.2) 90 to 10 wt. %, related to D), of an oligomeric phosphorus
compound of the formula (II) ##STR14## in which R.sup.4, R.sup.5,
R.sup.6, R.sup.7 are mutually independently cresyl, phenyl,
xylenyl, propylphenyl or butylphenyl, or brominated or chlorinated
derivatives thereof
n means 1,
y means an average value between 1 and 2, and
x means a residue derived from bisphenol A, rescorcinol or
hydroquinone, and
E) 0.05 to 5 parts by weight of a fluorinated polyolefin with an
average particle diameter of 0.05 to 1000 .mu.m, a density of 1.2
to 2.3 g/cm.sup.3 and a fluorine content of 65 to 76 wt.
%..Iaddend..Iadd.
13. Flame resistant, thermoplastic moulding compounds
containing
A) 40 to 98 parts by weight of an aromatic polycarbonate;
B) 3 to 50 parts by weight of a vinyl copolymer prepared from
B.1) 50 to 98 parts by weight of styrene, .alpha.-methylstyrene,
ring-substituted styrenes, C.sub.1 -C.sub.8 alkyl methacrylates,
C.sub.1 -C.sub.8 alkyl acrylates or mixtures thereof and
B.2) 50 to 2 parts by weight of acrylonitrile, methacrylonitrile,
C.sub.1 -C.sub.8 alkyl methacrylates, C.sub.1 -C.sub.8 alkyl
acrylates, maleic anhydride, N-substituted maleimides and mixtures
thereof;
C) 0.5 to 40 parts by weight of a graft polymer prepared from
C.1) 5 to 95 parts by weight of a mixture of
C.1.1) 50 to 95 parts by weight of styrene, .alpha.-methylstyrene,
halogen or methyl ring-substituted styrene, C.sub.1 -C.sub.8 alkyl
methacrylate, C.sub.1 -C.sub.8 alkyl acrylate, or mixtures of these
compounds and
C.1.2) 5 to 50 parts by weight of acrylonitrile, methacrylonitrile,
C.sub.1 -C.sub.8 alkyl methacrylates, C.sub.1 -C.sub.8 alkyl
acrylate, maleic anhydride, C.sub.1 -C.sub.4 alkyl or phenyl
N-substituted maleimides or mixtures of these compounds on
C.2) 5 to 95 parts by weight of a polymer with a glass transition
temperature of below -10.degree. C.,
D) 0.5 to 20 parts by weight of a mixture of
D.1) 14 to 40 wt. %, related to D), of a monophosphorus compound of
the formula (I) ##STR15## in which R.sup.1, R.sup.2 and R.sup.3 are
independently phenyl, cresyl, cumyl, naphthyl, chlorophenyl,
bromophenyl, pentachlorophenyl or pentabromophenyl
n means 1 and
D.2) 86 to 60 wt. %, related to D), of an oligomeric phosphorus
compound of the formula (II) ##STR16## in which R.sup.4, R.sup.5,
R.sup.6, R.sup.7 are independently cresyl, phenyl, xylenyl,
propylphenyl or butylphenyl, or brominated or chlorinated
derivatives thereof,
n means 1,
y has an average value between 1 and 2, and
x means a residue derived from bisphenol A, rescorcinol or
hydroquinone, and
E) 0.05 to 5 parts by weight of a fluorinated polyolefin with an
average particle diameter of 0.05 to 1000 .mu.m, a density of 1.2
to 2.3 g/cm.sup.3 and a fluorine content of 65 to 76 wt.
%..Iaddend.
Description
The present invention relates to flame resistant polycarbonate/ABS
moulding compounds whose stress cracking resistance is
substantially improved by a combination of additives comprising a
monophosphorus compound and an oligomeric phosphorus compound.
EP-A 0 174 493 (U.S. Pat. No. 4,983,658) describes flameproofed
polymer blends containing halogen prepared from an aromatic
polycarbonate, a graft copolymer containing styrene, monophosphates
and a special polytetrafluoroethylene formulation. While these
blends do indeed have adequate fire behaviour and mechanical
properties, they may be deficient in stress cracking
resistance.
U.S. Pat. No. 5,030,675 describes flame resistant, thermoplastic
moulding compounds prepared from an aromatic polycarbonate, ABS
polymer, polyalkylene terephthalate together with monophosphates
and fluorinated polyolefins as flame retardants. Good stress
cracking resistance is accompanied by deficiencies in notched
impact strength, together with unsatisfactory thermal stability
when exposed to elevated temperatures, such as for example during
processing.
Diphosphates are known as flame retardants. JA 59 202 240 describes
the production of such a product from phosphorus oxychloride,
diphenols such as hydroquinone or bisphenol A and monophenols such
as phenol or cresol. These diphosphates may be used as flame
retardants in polyamide or polycarbonate. However, this publication
contains no indication of any improvement in stress cracking
resistance by adding the oligomeric phosphate to polycarbonate
moulding compounds in conjunction with polyalkylene terephthalates.
EP-A 0 363 608 (=U.S. Pat. No. 5,204,394) describes polymer blends
prepared from an aromatic polycarbonate, a Copolymer or graft
copolymer containing styrene, together with oligomeric phosphates
as flame retardants. U.S. Pat. No. 5,061,745 describes polymer
blends prepared from an aromatic polycarbonate, ABS graft copolymer
and/or a copolymer containing styrene and monophosphates as flame
retardants. The stress cracking resistance of these blends is often
inadequate for the production of thin-walled casing components.
It has surprisingly now been found that flame resistant
polycarbonate/ABS moulding compounds with excellent stress cracking
resistance may be produced if a combination of additives comprising
a monophosphorus compound and an oligomeric phosphorus compound is
added. Particularly elevated stress cracking resistance is achieved
if the ratio by weight of the monophosphorus compound to the
oligomeric phosphorus compound is within the range 90:10 to 10:90.
These moulding compounds are particularly suitable for the
production of thin-walled mouldings (computer equipment casing
parts), where elevated processing temperatures and pressures result
in the exposure of the material used to considerable stress.
The present invention provides flame resistant, thermoplastic
moulding compounds prepared from
A) 40 to 98 parts by weight, preferably 50 to 95 parts by weight,
particularly preferably 60 to 90 parts by weight of an aromatic
polycarbonate,
B) 3 to 50, preferably 5 to 40 parts by weight of a vinyl copolymer
prepared from
B.1) 50 to 98, preferably 60 to 95 parts by weight of styrene,
.alpha.-methylstyrene, ring-substituted styrenes, C.sub.1 -C.sub.8
alkyl methacrylates, C.sub.1 -C.sub.8 alkyl acrylates or mixtures
thereof and
B.2) 50 to 2, preferably 40 to 5 parts by weight of acrylonitrile,
methacrylonitrile, C.sub.1 -C.sub.8 alkyl methacrylates, C.sub.1
-C.sub.8 alkyl acrylates, maleic anhydride, N-substituted
maleimides and mixtures thereof,
C) 0.5 to 40 parts by weight, preferably 1 to 20 parts by weight,
particularly preferably 2 to 12 parts by weight of a graft
polymer,
D) 0.5 to 20 parts by weight, preferably 1 to 18 parts by weight,
particularly preferably 2 to 15 parts by weight of a mixture of
D.1) 10 to 90 wt. %, preferably 12 to 50, in particular 14 to 40
wt. %, very particular 15 to 40 wt. % (related to the total
quantity of D) of a monophosphorus compound of the formula (I)
##STR3## in which R.sup.1, R.sup.2 and R.sup.3 mutually
independently mean optionally halogenated C.sub.1 -C.sub.8 alkyl,
C.sub.6 -C.sub.20 aryl or C.sub.7 -C.sub.12 aralkyl
m means 0 or 1 and
n means 0 or 1 and
D.2) 90 to 10 wt. %, preferably 88 to 50, in particular 86 to 60
wt. %, very particular 85 to 60 wt. % (related to the total amount
of D) of an oligomeric phosphorus compound of the formula (II)
##STR4## in which R.sup.4, R.sup.5, R.sup.6, R.sup.7 mutually
independently mean C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.6
cycloalkyl, C.sub.6 -C.sub.10 aryl or C.sub.7 -C.sub.12
aralkyl,
n mutually independently mean 0 or 1,
y means 1 to 5 and
X means a mono- or polycyclic aromatic residue with 6 to 30 C
atoms,
and
E) 0.05 to 5 parts by weight, preferably 0.1 to 1 part by weight,
particularly preferably 0.1 to 0.5 parts by weight of a fluorinated
polyolefin with an average particle diameter of 0.05 to 1000 .mu.m,
a density of 1.2 to 2.3 g/cm.sup.3 and a fluorine content of 65 to
76 wt. %.
The sum of all the parts by weight A+B+C+D+E is 100.
COMPONENT A
Suitable component A thermoplastic, aromatic polycarbonates
according to the invention are those based on diphenols of the
formula (III) ##STR5## in which A is a single bond, C.sub.1
-C.sub.5 alkylene, C.sub.2 -C.sub.5 alkylidene, C.sub.5 -C.sub.6
cycloalkylidene, --S-- or --SO.sub.2 --,
B is chlorine, bromine,
q is 0, 1 or 2 and
p is 1 or 0
or alkyl-substituted dihydroxyphenylcycloalkanes of the formula
(IV), ##STR6## in which R.sup.8 and R.sup.9 mutually independently
mean hydrogen, halogen, preferably chlorine or bromine, C.sub.1
-C.sub.8 alkyl, C.sub.5 -C.sub.6
cycloalkyl, C.sub.6 -C.sub.10 aryl, preferably phenyl, and C.sub.7
-C.sub.12 aralkyl, preferably phenyl-C.sub.1 -C.sub.4 -alkyl, in
particular benzyl,
m means an integer of 4, 5, 6 or 7, preferably 4 or 5,
R.sup.10 and R.sup.11 mean, individually selectable for each Z, and
mutually independently hydrogen or C.sub.1 -C.sub.6 alkyl
and
Z means carbon, provided that on at least one Z atom, R.sup.10 and
R.sup.11 simultaneously mean alkyl.
Suitable diphenols of the formula (III) are, for example,
hydroquinone, resorcinol, 4,4'-dihydroxydiphenyl,
2,2-bis-(4-hydroxyphenyl) propane,
2,4-bis-(4-hydroxyphenyl)-2-methylbutane,
1,1-bis-(4-hydroxyphenyl)-cyclohexane,
2,2-bis-(3-chloro-4-hydroxyphenyl) propane, 2,2-bis
-(3,5-dibromo-4-hydroxyphenyl)propane.
Preferred diphenols of the formula (III) are
2,2bis-(4-hydroxyphenyl)propane,
2,2-bis-(3,5-dichloro-4-hydroxyphenyl)propane and
1,1-bis-(4-hydroxyphenyl)cyclohexane.
Preferred diphenols of the formula (IV) are
1,1-bis-(4-hydroxyphenyl)-3,3-dimethylcyclohexane,
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and
1,1-bis-(4-hydroxyphenyl)-2,4,4-trimethylcyclopentane.
Both homopolycarbonates and copolycarbonates are suitable
polycarbonates according to the invention.
Component A may also be a blend of the thermoplastic polycarbonates
specified above.
Polycarbonates may be produced in a known manner from diphenols
with phosgene using the phase interface process or with phosgene
using the homogeneous phase process, the so-called pyridine
process, wherein molecular weight may be adjusted in a known manner
with an appropriate quantity of known chain terminators.
Suitable chain terminators are, for example, not only phenol,
p-chlorophenol, p-tert.-butylphenol or 2,4,6-tribromophenol, but
also long-chain alkylphenols such as 4-(1,3-tetramethylbutyl)phenol
according to DE-OS 2 842 005 (Le A 19 006) or monoalkylphenol or
dialkylphenol with a total of 8 to 20 C atoms in the alkyl
substituents according to German patent application P 3 506 472.2
(Le A 23 654), such as 3,5-di-tert.-butylphenol, p-iso-octylphenol,
p-tert.-octylphenol, p-dodecylphenol and
2-(3,5-dimethylheptyl)phenol and 4-(3,5-dimethylheptyl)phenol.
The quantity of chain terminators is in general between 0.5 and 10
mol. %, related to the sum of the diphenols of the formulae (III)
and/or (IV) used in each case.
Suitable polycarbonates A according to the invention have average
molecular weights (M.sub.w, weight average measured for example by
ultracentrifugation or light scattering) of 10,000 to 200,000,
preferably of 20,000 to 80,000.
Suitable polycarbonates A according to the invention may be
branched in a known manner, in particular preferably by
incorporation 0.05 to 2 mol. %, related to total quantity of
diphenols used, of tri- or higher functional compounds, for example
those with three or more phenolic groups.
In addition to bisphenol A homopolycarbonate, preferred
polycarbonates are copolycarbonates of bisphenol A with up to 15
mol. %, related to the total molar quantities of diphenols, of
2,2-bis-(3,5-dibromo-4-hydroxylphenyl) propane and the
copolycarbonates of bisphenol A with up to 60 mol. %, related to
the total molar quantities of diphenols, of
1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethyl-cyclohexane.
The polycarbonates A may be partially or entirely replaced with
aromatic polyester-carbonates.
COMPONENT B
Component B vinyl copolymers which may be used according to the
invention are those prepared from at least one monomer of the
group: styrene, .alpha.-methylstyrene and/or ring-substituted
styrenes, C.sub.1 -C.sub.8 alkyl methacrylate, C.sub.1 -C.sub.8
alkyl acrylate (B.1) with at least one monomer from the group:
acrylonitrile, methacrylonitrile, C.sub.1 -C.sub.8 alkyl
methacrylate, C.sub.1 -C.sub.8 alkyl acrylate, maleic anhydride
and/or N-substituted maleimide (B.2).
C.sub.1 -C.sub.8 alkyl acrylates or C.sub.1 -C.sub.8 alkyl
methacrylates are esters of acrylic or methacrylic acids
respectively with monohydric alcohols with 1 to 8 C atoms. Methyl
methacrylate, ethyl methacrylate and propyl methacrylate are
particularly preferred. Methyl methacrylate is cited as a
particularly preferred methacrylic acid ester. Thermoplastic
copolymers of a composition according to component B may be
produced as secondary products of graft polymerisation during
production of component C, particularly if large quantities of
monomers are grafted onto small quantities of rubber. The quantity
of copolymer B to be used according to the invention does not
include these secondary products of graft polymerisation.
The component B copolymers are resinous, thermoplastic and contain
no rubber.
The thermoplastic copolymers B contain 50 to 98, preferably 60 to
95 parts by weight of B.1 and 50 to 2, preferably 40 to 5 parts by
weight of B.2.
Particularly preferred copolymers B are those prepared from styrene
with acrylonitrile and optionally methyl methacrylate, from
.alpha.-methylstyrene with acrylonitrile and optionally methyl
methacrylate or from styrene and .alpha.-methylstyrene with
acrylonitrile and optionally methyl methacrylate.
The component B styrene/acrylonitrile copolymers are known any may
be produced by free-radical polymerisation, in particular by
emulsion, suspension, solution or bulk polymerisation. The
component B copolymers preferably have molecular weights M.sub.w
(weight average, determined by light scattering or setting) of
between 15,000 and 200,000.
Particularly preferred copolymers B according to the invention are
also random copolymers of styrene and maleic anhydride, which may
be produced from the corresponding monomers by continuous bulk or
solution polymerisation with incomplete conversion.
The proportions of the two components in the suitable random
styrene-maleic anhydride copolymers according to the invention may
be varied within a wide range. The preferred maleic anhydride
content is between 5 and 25 wt. %.
The molecular weights (number average, M.sub.n) of the suitable
component B random styrene/maleic anhydride copolymers according to
the invention may vary over a wide range. A range of 60,000 to
200,000 is preferred. An intrinsic viscosity of 0.3 to 0.9 is
preferred for these products (measured in dimethylformamide at
25.degree. C.; see Hoffmann, Kromer, Kuhn, Polymeranalytik I,
Stuttgart 1977, p. 316 et seq.).
Instead of styrene, the vinyl copolymers B may also contain
ring-substituted styrenes such as p-methylstyrene, vinyltoluene,
2,4-dimethylstyrene, and other substituted styrenes such as
.alpha.-methylstyrene.
COMPONENT C
The graft polymers C) comprise, for example, graft copolymers with
rubber-elastic properties, which are substantially obtainable from
at least two of the following monomers: chloroprene, 1,3-butadiene,
isoprene, styrene, acrylonitrile, ethylene, propylene, vinyl
acetate and (meth) acrylic acid esters with 1 to 18 C atoms in the
alcohol component; i.e. polymers as are, for example, described in
Methoden der Organischen Chemie (Houben-Weyl), vol. 14/1, Georg
Thieme Verlag, Stuttgart 1961, p. 393-406 and in C. B. Bucknall,
Toughened Plastics, Appl. Science Publishers, London 1977.
Preferred polymers C) are partially crosslinked and have a gel
content of above 20 wt. %, preferably of above 40 wt. %, in
particular above 60 wt. %.
Preferred graft polymers C) comprise graft copolymers prepared
from:
C.1) 5 to 95, preferably 30 to 80 parts by weight of a mixture
of
C.1.1) 50 to 95 parts by weight of styrene, .alpha.-methylstyrene,
halogen or methyl ring-substituted styrene, C.sub.1 -C.sub.8 alkyl
methacrylate, in particular methyl methacrylate, C.sub.1 -C.sub.8
alkyl acrylate, in particular methyl acrylate, or mixtures of these
compounds and
C.1.2) 5 to 50 parts by weight of acrylonitrile, methacrylonitrile,
C.sub.1 -C.sub.8 alkyl methacrylates, in particular methyl
methacrylate, C.sub.1 -C.sub.8 alkyl acrylate, in particular methyl
acrylate, maleic anhydride, C.sub.1 -C.sub.4 alkyl or phenyl
N-substituted maleimides or mixtures of these compounds on
C.2) 5 to 95, preferably 20 to 70 parts by weight of a polymer with
a glass transition temperature of below -10.degree. C.
Preferred graft polymers C) are, for example, polybutadienes,
butadiene/styrene copolymers and acrylate rubbers grafted with
styrene and/or acrylonitrile and/or (meth)acrylic acid alkyl
esters; i.e. copolymers of the type described in DE-OS 1 694 173
(=U.S. Pat. No. 3,564,077); polybutadienes, butadiene/styrene or
butadiene/ acrylonitrile copolymers, polyisobutenes or
polyisoprenes grafted with acrylic or methacrylic acid alkyl
esters, vinyl acetate, acrylonitrile, styrene and/or alkylstyrenes,
as are, for example, described in DE-OS 2 348 377 (=U.S. Pat. No.
3,919,353).
Particularly preferred polymers C) are, for example, ABS polymers,
as are for example described in DE-OS 2 035 390 (=U.S. Pat. No.
3,644,574) or in DE-OS 2 248 242 (GB patent 1,409,275).
Particularly preferred graft polymers C) are graft polymers
obtainable by the grafting reaction of
I. 10 to 70, preferably 15 to 50, in particular 20 to 40 wt. %,
related to the grafted product, of at least one (meth) acrylic acid
ester of 10 to 70, preferably 15 to 50, in particular 20 to 40 wt.
% of a mixture of 10 to 50, preferably 20 to 35 wt. %, related to
the mixture, of acrylonitrile or (meth)acrylic acid ester and 50 to
90, preferably 65 to 80 wt. %, related to the mixture, of styrene
onto
II. 30 to 90, preferably 50 to 85, in particular 60 to
80 wt. %, related to the grafted product, of a butadiene polymer
with at least 50 wt. %, related to IL butadiene residues as the
grafting backbone,
wherein the gel content of the grafting backbone II is at least 70
wt. % (measured in toluene), the degree of grafting G of the graft
polymer C) is 0.15 to 0.55 and its average particle diameter
d.sub.50 0.05 to 2, preferably 0.1 to 0.6 .mu.m.
(Meth) acrylic acid esters I are esters of acrylic acid or
methacrylic acid and monohydric alcohols with 1 to 18 C atoms.
Methyl, ethyl and propyl methacrylate and particularly
preferred.
In addition to butadiene residues, the grafting backbone II may
contain up to 50 wt. %, related to II, of residues of other
ethylenically unsaturated monomers, such as styrene, acrylonitrile,
esters of acrylic or methacrylic acid with 1 to 4 C atoms in the
alcohol component (such as methyl acrylate, ethyl acrylate, methyl
methacrylate, ethyl methacrylate), vinyl esters and/or vinyl
ethers. The preferred grafting backbone II consists of pure
polybutadiene.
Since, as is known, the graft monomers are not necessarily entirely
grafted onto the grafting backbone, graft polymers C) according to
the invention are also taken to be those products obtained by
polymerisation of the graft monomers in the presence of the
grafting backbone.
The degree of grafting G describes the ratio by weight of grafted
monomers to the grafting backbone and is dimensionless.
The average particle size d.sub.50 is the diameter both above and
below which are found 50 wt. % of the particles. This value may be
determined by ultracentrifuge measurements (W. Scholtan, H. Lange,
Kolloid Z. & Z. Polymere 250 (1972), 782-796).
Particularly preferred graft polymers C) are also, for example,
graft polymers of
(a) 20 to 90 wt. %, related to C), of acrylate rubber with a glass
transition temperature of below -20.degree. C. as the grafting
backbone and
(b) 10 to 80 wt. %, related to C), of at least one polymerisable,
ethylenically unsaturated monomer, the homo- or copolymers of
which, if formed in the absence of a), would have a glass
transition temperature of above 25.degree. C., as the graft
monomers.
The acrylate rubbers (a) of the polymers C) are preferably polymers
of acrylic acid alkyl esters, optionally with up to 40 wt. %,
related to (a), of other polymerisable, ethylenically unsaturated
monomers. Preferred polymerisable acrylic acid esters include
C.sub.1 -C.sub.8 alkyl esters, for example methyl, ethyl, n-butyl,
n-octyl and 2-ethylhexyl acrylate; halogenalkyl esters, preferably
halogen-C.sub.1 -C.sub.8 -alkyl esters, such as chloroethyl
acrylate, together with mixtures of these monomers.
To achieve crosslinking, monomers with more than one polymerisable
double bond may be copolymerised. 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 for example ethylene glycol dimethacrylate,
allyl methacrylate; polyunsaturated heterocyclic compounds, such as
for example trivinyl and triallyl cyanurate; polyfunctional vinyl
compounds, such as di- and trivinylbenzenes; but also triallyl
phosphate and diallyl phthalate.
Preferred crosslinking monomers are allyl methacrylate, ethylene
glycol dimethylacrylate, diallyl phthalate and heterocyclic
compounds containing at least 3 ethylenically unsaturated
groups.
Particularly preferred crosslinking monomers are the cyclic
monomers triallyl cyanurate, triallyl isocyanurate, trivinyl
cyanurate, triacryloylhexahydro-s-triazine, triallylbenzenes.
The quantity of crosslinking monomers is preferably 0.02 to 5, in
particular 0.05 to 2 wt. %, related to the grafting backbone
(a).
In the case of cyclic crosslinking monomers with at least 3
ethylenically unsaturated groups, it is advantageous to limit the
quantity of below 1 wt. % of the grafting backbone (a).
Other than the acrylic acid esters, preferred polymerisable,
ethylenically unsaturated monomers which may optionally be used to
produce the grafting backbone (a) are, for example, acrylonitrile,
styrene, .alpha.-methylstyrene, acrylamides, vinyl-C.sub.1 -C.sub.6
-alkyl ethers, methyl methacrylate, butadiene. Preferred acrylate
rubbers as the grafting backbone (a) are emulsion polymers having a
gel content of at least 60 wt. %.
Further suitable grafting backbones are silicone rubbers with
active grafting sites, as are described in DE-OS 37 04 657, DE-OS
37 04 655, DE-OS 36 31 540 and DE-OS 36 31 539.
The gel content of the grafting backbone (a) is determined in
dimethylformamide at 25.degree. C. (M. Hoffmann, H. Kromer, R.
Kuhn, Polymeranalytik I & II, Georg Thieme Verlag, Stuttgart
1977).
The aqueous dispersions of graft polymer C) to be used for the
preferred embodiment of coprecipitation with the
tetrafluoroethylene polymer E) generally have solids contents of 25
to 60, preferably 30 to 45 wt. %.
COMPONENT D
The polymer blends according to the invention contain as flame
retardant a mixture of a monophosphorus compound D.1) and a
oligomeric phosphorus compound D.2). Component D.1) is a phosphorus
compound according to the formula (I) ##STR7## in which formula,
R.sup.1, R.sup.2 and R.sup.3 mutually independently mean optionally
halogenated C.sub.1 -C.sub.8 alkyl, C.sub.6 -C.sub.20 aryl or
C.sub.7 -C.sub.12 aralkyl
m means 0 or 1 and
n means 0 or 1.
The phosphorus compounds according to component D.1) which are
suitable according to the invention are generally known (see, for
example, Ullmanns Enzyklopaadie der technischen Chemie, vol. 18, p.
301 et seq. 1979; Houben-Weyl, Methoden der Organischen Chemie,
Vol. 12/1, p. 43; Beilstein, vol. 6, p. 177). Preferred
substituents R.sup.m to R.sup.s comprise methyl, butyl, octyl,
chloroethyl, 2-chloropropyl, 2,3-dibromopropyl, phenyl, cresyl,
cumyl, naphthyl, chlorophenyl, bromophenyl, pentachlorophenyl and
pentabromophenyl. Methyl, ethyl, butyl, phenyl, the latter
optionally substituted with methyl, ethyl, chlorine and/or bromine,
are particularly preferred.
Preferred phosphorus compounds D.1) (formula (I)) comprise, for
example, tributyl phosphate, tris-(2-chloroethyl) phosphate,
tris-(2,3-dibromopropyl) phosphate, triphenyl phosphate, tricresyl
phosphate, diphenylcresyl phosphate, diphenyloctyl phosphate,
diphenyl-2-ethylcresyl phosphate, tri-(isopropylphenyl) phosphate,
halogen-substituted aryl phosphates, methylphosphonic acid dimethyl
ester, methylphosphonic acid diphenyl ester, phenylphosphonic acid
diethyl ester, triphenylphosphine oxide and tricresylphosphine
oxide.
Component D.2) is an oligomeric phosphorus compound of the formula
(II). ##STR8##
In the formula, R.sup.4, R.sup.5, R.sup.6, R.sup.7 mutually
independently mean C.sub.1 -C.sub.8 alkyl, C.sub.5 -C.sub.6
cycloalkyl, C.sub.6 -C.sub.10 aryl or C.sub.7 -C.sub.12 aralkyl,
C.sub.6 -C.sub.10 aryl or C.sub.7 -C.sub.12 aralkyl being
preferred. The aromatic groups R.sup.4, R.sup.5, R.sup.6, R.sup.7
may in themselves be substituted with halogen or alkyl groups.
Particularly preferred aryl residues are cresyl, phenyl, xylenyl,
propylphenyl or butylphenyl, together with the brominated and
chlorinated derivatives thereof.
X in the formula (II) means a mono- or polycyclic aromatic residue
with 6 to 30 C atoms. This residue is derived from diphenols such
as, for example, bisphenol A, resorcinol or hydroquinone or also
the chlorinated or brominated derivatives thereof.
The values of n in the formula (II) may mutually independently be 0
or 1, n preferably equalling 1.
y may have values between 1 and 5, preferably between 1 and 2.
Mixtures of various oligomeric phosphates may also be used as
component D.2) according to the invention. In this case, y has an
average value between 1 and 5, preferably between 1 and 2.
The polymer blends according to the invention contain as flame
retardant a mixture of D. 1) and D.2). The weight ratios of D.1)
and D.2) have to be chosen in such a manner to achieve a
synergistic effect. The mixture generally consists of 10 to 90 wt.
% of D.1) and 90 to 10 wt. % of D.2) (related to D) in each case).
Particularly favourable properties are achieved in the preferred
and particularly preferred range of about 12 to 50 and 14 to 40 wt.
% of D.1) and 88 to 50 wt. % and 86 to 60 wt. % of D.2). Very
particul- arly preferred is the range of 15 to 40 wt. % of D.1) and
85 to 60 wt. % of D.2).
COMPONENT E
The fluorinated polyolefins E) are of high molecular weight and
have glass transition temperatures of above -30.degree. C.,
generally of about 100.degree. C., fluorine contents preferably of
65 to 76, in particular of 70 to 76 wt. %, average particle
diameters d.sub.50 of 0.05 to 1000, preferably of 0.08 to 20 .mu.m.
In general, the fluorinated polyolefins E) have a density of 1.2 to
2.3 g/cm.sup.3. Preferred fluorinated polyolefins E) are
polytetrafluoroethylene, polyvinylidene fluoride,
tetrafluoroethylene/hexafluoropropylene and
ethylene/tetrafluoroethylene copolymers. The fluorinated
polyolefins and know (c.f. Vinyl and Related Polymers by
Schildknecht, John Wiley & Sons Inc., New York, 1962, p.
484-494; Fluoropolymers by Wall, Wiley-Interscience, John Wiley
& Sons Inc., New York, vol. 13, 1970, p. 623-654; Modern
Plastics Encyclopedia, 1970-1971, vol. 47, n.degree. 10 A, October
1970, McGraw-Hill Inc., New York, p. 134 and 774; Modern Plastics
Encyclopedia, 1975-1976, October 1975, vol. 52, n.degree. 10 A,
McGraw-Hill Inc., New York, p. 27, 28 & 472 and U.S. Pat. Nos.
3,671,487, 3,723,373 and 3,838,092).
These polymers may be produced using known processes, such as for
example by polymerisation of tetrafluoroethylene in an aqueous
medium with a free radical forming catalyst, for example sodium,
potassium or ammonium peroxydisulphate at pressures of 7 to 71
kg/cm.sup.2 and at temperatures of 0.degree. to 200.degree. C.,
preferably at temperatures of 20.degree. to 100.degree. C. (For
further details, see for example U.S. Pat. No. 2,393,967).
Depending upon the form in which it is used, the density of these
materials may be between 1.2 and 2.3 g/cm.sup.3 and average
particle sizes between 0.05 and 1000
Preferred fluorinated polyolefins E) according to the invention are
tetrafluoroethylene polymers with average particle diameters of
0.05 to 20 .mu.m, preferably of 0.08 to 10 .mu.m, and a density of
1.2 to 1.9 g/cm.sup.3, which are preferably used in the form of a
coagulated mixture of emulsions of the tetrafluoroethylene polymers
E) with emulsions of the graft polymers C).
Suitable fluorinated polyolefins E) which may be used in powder
form are tetrafluoroethylene polymers with average particle sizes
of 100 to 1000 .mu.m and densities of 2.0 g/cm.sup.3 to 2.3
g/cm.sup.3.
In order to produce a coagulated mixture of C) and E), an aqueous
emulsion (latex) of a graft polymer C) with an average latex
particle diameter of 0.05 to 2 .mu.m, in particular 0.1 to 0.6
.mu.m, is first of all blended with a finely divided emulsion of a
tetrafluoroethylene polymer E) in water with an average particle
diameter of 0.05 to 20 .mu.m, in particular 0.08 to 10 .mu.m;
suitable tetrafluoroethylene polymer emulsions customarily have
solids contents of 30 to 70 wt. %, in particular 50 to 60 wt. %.
The emulsions of the graft polymer C) have solids contents of 25 to
50 wt. %, preferably of 30 to 45 wt. %.
The stated quantity in the description of component C) excludes the
proportion of the graft polymer for the coagulated mixture of graft
polymer and fluorinated polyolefins.
In the emulsion mixture, the ratio by weight of graft polymer C) to
the tetrafluoroethylene polymer E) is 95:5 to 60:40. The emulsion
mixture is then coagulated in a known manner, for example by spray
drying, freeze drying or coagulation by adding inorganic or organic
salts, acids, bases or organic, water-miscible solvents such as
alcohols, ketones, preferably at temperatures of 20.degree. to
150.degree. C., in particular of 50.degree. to 100.degree. C. If
necessary, drying may be performed at 50.degree. to 200.degree. C,
preferably 70.degree. to 100.degree. C.
Suitable tetrafluoroethylene polymer emulsions are customary
commercial products offered for sale, for example, by the company
DuPont as Teflone.RTM. 30N.
The moulding compounds according to the invention may contain
customary additives such as lubricants and mould release agents,
nucleating agents, antistatic agents, stabilisers, fillers and
reinforcing materials, together with dyes and pigments. The filled
or reinforced moulding compounds may contain up to 60, preferably
10 to 40 wt. %, related to the filled or reinforced moulding
compound, of fillers and/or reinforcing materials. Glass fibre is
the preferred reinforcing material. Preferred fillers, which may
also have a reinforcing effect, are glass beads, mica, silicates,
quartz, talcum, titanium dioxide, wollastonite.
The moulding compounds according to the invention consisting of
components A to E and optionally further known additives such as
stabilisers, dyes, pigments, lubricants and mould release agents,
fillers and reinforcing materials, nucleating agents together with
antistatic agents are produced by mixing together the particular
constituents in a known manner and melt-compounding or
melt-extruding them at temperatures of 200.degree. C. to
330.degree. C. in customary equipment, such as internal kneaders,
extruders and double screw extruders, wherein component E) is
preferably used in the form of the already mentioned coagulated
mixture.
The present invention thus also provides a process for the
production of thermoplastic moulding compounds consisting of
components A to E, optionally together with stabilisers, dyes,
pigments, lubricants and mould release agents, fillers and
reinforcing materials, nucleating agents, together with antistatic
agents, which is characterised in that, once components A to E,
optionally together with stabilisers, dyes, pigments, plasticisers,
fillers and reinforcing materials, lubricants and mould release
agents, nucleating agents and/or antistatic agents are mixed
together, they are melt-compounded or melt-extruded in customary
equipment at temperatures of 200.degree. to 330.degree., wherein
component E is preferably used in the form of a coagulated mixture
with component C. The individual constituents may be mixed together
in a known manner both consecutively and simultaneously, and both
at approximately 20.degree. C. (room temperature) and at higher
temperatures.
The moulding compounds according to the present invention may be
used to produce mouldings of any kind. In particular, mouldings may
be produced by injection moulding. Examples of articles which may
be moulded are: casing parts of any kind, for example for household
appliances such as juice extractors, coffee machines, food mixers,
for office equipment or cover plates for the construction sector
and motor vehicle components. The moulding compounds are also used
in electrical engineering because they have very good electrical
properties.
The moulding compounds are particularly suitable for the production
of thin-walled mouldings (for example computer casing parts), which
are required to exhibit particularly high notched impact strength
and stress cracking resistance.
Another type of processing is the production of mouldings by
blowmoulding or by thermaforming previously produced sheet or
film.
EXAMPLES
Component A
Bisphenol A based polycarbonate with a relative solution viscosity
of 1.26 to 1.28 measured in methylene chloride at 25.degree. C. at
a concentration of 0.5 g/100 ml.
Component B
Styrene/acrylonitrile copolymer with a stryene/acrylonitrile ratio
of 72:28 and an intrinsic viscosity of 55 dl/g (measured in
dimethylformamide at 20.degree. C).
Component C
Graft polymer of 45 parts by weight of styrene and acrylonitrile in
a ratio of 72:28 on 55 parts by weight of particulate, crosslinked
polybutadiene rubber (average particle diameter d.sub.50 =0.4
.mu.m), produced by emulsion polymerisation.
Component D
D.1) triphenyl phosphate (Disflamoll.RTM. TP from Bayer AG) D.2)
m-phenylene-bis(diphenylphosphate) (Fyroflex RDP from Akzo)
Component E
Tetrafluoroethylene polymer as a coagulated mixture prepared from
an aqueous emulsion of SAN graft polymer according to C) and an
aqueous emulsion of tetrafluoroethylene polymer. The ratio by
weight of the graft polymer C) to the tetrafluoroethylene polymer
E) in the mixture is 90 wt. % to 10 wt. %. The tetrafluoroethylene
polymer emulsion has a solids content of 60 wt. % and average
particle diameter is between 0.05 and 0.5 .mu.m. The SAN graft
polymer emulsion has a solids content of 34 wt. % and an average
latex particle diameter of 0.4 .mu.m.
PRODUCTION OF E
The emulsion of the tetrafluoroethylene polymer (Teflon 30 N from
DuPont) is blended with the SAN graft polymer emulsion C) and
stabilised with 1.8 wt. %, related to polymer solids, of phenolic
antioxidants. At 85.degree. to 95.degree. C., the mixture is
coagulated with an aqueous solution of MgSO.sub.4 (Epsom salts) and
acetic acid at pH 4 to 5, filtered and washed until virtually free
of electrolytes, the majority of the water is then eliminated by
centrifugation and the product dried at 100.degree. C. to give a
powder. This powder may then be compounded with the other
components in the described equipment.
Production and Testing of Moulding Compounds According to the
Invention
Components A to E were mixed together in a 3-1 internal kneader.
The mouldings were produced on an Arburg 270 E injection moulding
machine at 260.degree. C.
Stress cracking behaviour was determined on bars of dimensions
80.times.10.times.4 mm, melt temperature 260.degree. C. The test
medium was a mixture of 60 vol. % toluene and 40 vol. %
isopropanol. The test pieces were pre-stressed on a circular arc
template (elongation 2.4%) and stored in the test medium at room
temperature. Stress cracking behaviour was determined by assessing
cracking or failure as a function of length of exposure to the test
medium.
The composition of the tested materials and the results obtained
are summarised in the following table.
It may be seen from the table that the comparative examples 1 and 8
with pure component D.2) and D.1) respectively have distinctly
lower stress cracking resistance than examples 2 to 7 according to
the invention.
TABLE ______________________________________ Composition and
propeties of moulding compounds Failure at Components [parts by
weight] .epsilon..sub.x = 2.4% Example A B C D.1 D.2 E [minutes]
______________________________________ 1 (comparison) 67 10 7.5 --
10 3.5 3.4 2 67 10 7.5 1 9 3.5 3.5 3 67 10 7.5 1.5 8.5 3.5 4.7 4 67
10 7.5 2 8 3.5 5.6 5 67 10 7.5 3 7 3.5 4.7 6 67 10 7.5 4 6 3.5 4.3
7 67 10 7.5 5 5 3.5 3.4 8 (comparison) 67 10 7.5 10 -- 3.5 2.5
______________________________________
* * * * *