Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-11-17
2004-03-16
Szekely, Peter (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S145000
Reexamination Certificate
active
06706788
ABSTRACT:
The present invention relates to flame resistant moulding compositions of polycarbonates and graft polymers, which are provided with their flame resistant properties by an active additive combination of a monophosphorus compound and an oligomeric phosphorus compound. The moulding compositions according to the invention are distinguished by high heat resistance, very high weld line strength and excellent flame resistance.
EP-A 0 174 493 (U.S. Pat. No. 4 983 658) describes flameproofed, halogen-containing polymer mixtures of aromatic polycarbonate, styrene-containing graft copolymer, monophosphates and a special polytetrafluoroethylene formulation. Although these mixtures are adequate in terms of their fire behaviour and the level of their mechanical values, deficiencies may occur in their weld line strength and their thermal stability.
In U.S. Pat. No. 5 030 675, flame resistant, thermoplastic moulding compositions consisting of aromatic polycarbonate, ABS polymer, polyalkylene terephthalate, together with monophosphates and fluorinated polyolefins as flame retardants, are described. Good stress cracking resistance and weld line strength are opposed by the disadvantages of deficiencies in their notched impact strength and inadequate thermal stability under high thermal stress, such as, for example, during processing. Another disadvantage may be seen in the fact that relatively large quantities of flame retardant are needed to achieve effective flameproofing, which greatly reduce the heat resistance.
Diphosphates are known as flame retardants. In JA 59 202 240 the preparation of such a product from phosphorus oxychloride, diphenols such as hydroquinone or bisphenol A and monophenols such as phenol or cresol is described. These diphosphates may be used as flame retardants in polyamide or polycarbonate.
In EP-A 0 363 608 (=U.S. Pat. No. 5 204 394), polymer mixtures of aromatic polycarbonate, styrene-containing copolymer and graft copolymer together with oligomeric phosphates as flame retardants are described. Although these mixtures display good flame resistance and reduced mould plate-out, they do not possess the high weld line strength and flame retardant effect required for many applications. As the molecular weight of the oligomeric phosphates increases, the effectiveness in terms of flame proofing decreases.
In EP-A 0 640 655, moulding compositions consisting of polycarbonate, styrene copolymer, ABS graft polymers and a combination of monophosphates and oligomeric phosphates as flame retardants are described. Here again, the low weld line strength caused by the styrene copolymers should be mentioned as a disadvantage.
According to DE-A 195 47 013, moulding compositions consisting of polycarbonate, graft polymer and oligomeric phosphates as flame retardants possess excellent flame resistance. No monophosphates are contained in the moulding compositions according to the invention.
In EP-A 0 731 140, polymer mixtures of polycarbonate, graft polymer and a combination of monophosphates and oligomeric phosphates as flame retardants are described. These mixtures possess good flame resistance and good thermal stability. However, it is a disadvantage that at least 5 parts by weight of the phosphorus compound are required to achieve an effective flame retardant (V-0 for 1.6 mm thickness according to UL 94 V), which has negative effects on heat resistance.
Surprisingly, it has now been found that halogen-free moulding compositions consisting of polycarbonate, graft polymer and a flame retardant combination of a monophosphorus compound and a phosphorus compound have a very favourable combination of properties of high heat resistance, good mechanical level (notched impact strength, weld line strength) and excellent flame resistance.
The invention provides flame resistant, thermoplastic moulding compositions containing
A) 70 to 98 parts by weight, preferably 75 to 98 parts by weight, particularly preferably 80 to 98 parts by weight, of an aromatic polycarbonate,
B) 0.5 to 20 parts by weight, preferably 1 to 20 parts by weight, particularly preferably 2 to 12 parts by weight, of a graft polymer,
C) 0.5 to 5 parts by weight, preferably 0.5 to 4 parts by weight, particularly preferably 0.5 to 3 parts by weight, of a mixture of
C.1) 10 to 90 wt. %, preferably 12 to 50, particularly 14 to 40, especially preferably 15 to 40 wt. % (based on the total quantity of C), of a monophosphorus compound of formula (I)
where
R
1
, R
2
and R
3
, independently of one another, signify C
1
-C
8
-alkyl, C
6
-C
20
-aryl or C
7
-C
12
-aralkyl,
m signifies 0 or 1 and
n signifies 0 or 1 and
C.2) 90 to 10 wt. %, preferably 88 to 50, particularly 86 to 60, especially preferably 85 to 60 wt. % (based on the total quantity of C), of a phosphorus compound of formula (II)
where
R
4
, R
5
, R
6
, R
7
, independently of one another, signify C
1
-C
8
-alkyl, C
5
-C
6
-cycloalkyl, C
6
-C
10
-aryl or C
7
-C
12
-aralkyl,
I independently of one another, signifies 0 or 1,
N signifies 1 to 5 and
X signifies a mononuclear or polynuclear aromatic radical with 6 to 30 C atoms,
D) 0.05 to 5 parts by weight, preferably 0.1 to 2 parts by weight, particularly preferably 0.1 to 1 part by weight of a fluorinated polyolefin with an average particle diameter of 0.05 to 1000 &mgr;m, a density of 1.2 to 2.3 g/cm
3
and a fluorine content of 65 to 76 wt. %.
Component A
Thermoplastic, aromatic polycarbonates according to component A that are suitable according to the invention are those based on the diphenols of formula (III)
where
A signifies a single bond, C
1
-C
5
-alkylene, C
2
-C
5
-alkylidene, C
5
-C
6
-cyclo-alkylidene, —S— or —SO
2
—,
B independently of one another signify C
1
-C
8
alkyl, C
6
-C
10
aryl, C
7
-C
12
aralkyl
q signifies 0, 1 or 2 and
p signifies 1 or 0
or alkyl-substituted dihydroxyphenylcycloalkanes of formula (IV),
where
R
8
and R
9
, independently of one another, signify hydrogen, C
1
-C
8
-alkyl, C
5
-C
6
-cycloalkyl, C
6
-C
10
-aryl, preferably phenyl, and C
7
-C
12
-aralkyl, preferably phenyl-C
1
-C
4
-alkyl, particularly benzyl,
m signifies an integer from 4, 5, 6 or 7, preferably 4 or 5,
R
10
and R
11
, selectable individually for each Z and independently of one another, signify hydrogen or C
1
-C
6
-alkyl and
Z signifies carbon, with the proviso that R
10
and R
11
both signify alkyl simultaneously on at least one Z atom.
Suitable diphenols of formula (III) are, e.g., hydroquinone, resorcinol, 4,4′-dihydroxydiphenyl, 2,2-bis(4-hydroxyphenyl)propane, 2,4-bis(4-hydroxyphenyl)-2-methylbutane, 1,1-bis(4-hydroxyphenyl)cyclohexane.
Preferred diphenols of formula (III) are 2,2-bis(4-hydroxyphenyl)propane, 2,2- and 1,1-bis(4-hydroxyphenyl)cyclohexane.
Preferred diphenols of formula (IV) are 1,1-bis(4-hydroxyphenyl)-3,3-dimethyl-cyclohexane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane and 1,1-bis(4-hydroxyphenyl)-2,4,4-trimethylcyclopentane.
Polycarbonates that are suitable according to the invention are both homopolycarbonates and copolycarbonates.
Component A may also be a mixture of the thermoplastic polycarbonates defined above.
Polycarbonates may be produced by known means from diphenols with phosgene by the phase boundary process, or with phosgene by the homogeneous phase process, the so-called pyridine process, the molecular weight being adjustable by known means by an appropriate quantity of known chain terminators.
Suitable chain terminators are, e.g., phenol, p-tert-butylphenol or else long-chain alkylphenols, such as 4-(1,3-tetramethylbutyl)phenol according to DE-OS 2 842 005 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, such as 3,5-di-tert-butylphenol, p-isooctylphenol), p-tert-octylphenol, p-dodecylphenol and 2-(3,5-dimethylheptyl)phenol and 4-(3,5-dimethylheptyl)phenol.
The quantity of chain terminators is generally between 0.5 and 10 mole %, based on the sum of the diphenols of formulae (III) and/or (IV) used in each case.
The polycarbonates A that are suitable ac
Alberts Heinrich
Bödiger Michael
Eckel Thomas
Horn Klaus
Wittmann Dieter
Preis Aron
Szekely Peter
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