Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Reexamination Certificate
1999-02-22
2001-05-15
Moore, Margaret G. (Department: 1712)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
C525S101000, C525S100000, C525S464000, C524S140000, C524S141000, C524S143000, C524S145000, C524S127000
Reexamination Certificate
active
06232397
ABSTRACT:
The present invention relates to molding materials which contain, as essential components,
A) from 25 to 95.4% by weight of at least one aromatic polycarbonate,
B) from 2 to 30% by weight of at least one graft polymer composed of
b
1
) from 40 to 80% by weight of a grafting base comprising an elastomeric polymer based on alkyl acrylates where the alkyl radical is of from 1 to 8 carbon atoms and having a glass transition temperature of less than 10° C.
b
2
) from 20 to 60% by weight of a graft layer comprising
b
21
) from 60 to 95% by weight of styrene or substituted styrenes of the general formula I
where R is alkyl of 1 to 8 carbon atoms or hydrogen, R
1
is alkyl of 1 to 8 carbon atoms and n is 1, 2 or 3, and
b
22
) from 5 to 40% by weight of at least one unsaturated nitrile,
C) from 2 to 50% by weight of a copolymer of
c
1
) from 60 to 95% by weight of styrene or substituted styrenes of the general formula I or mixtures thereof
c
2
) from 5 to 40% by weight of at least one unsaturated nitrile,
D) from 0.5 to 25% by weight of at least one network rubber based on siloxanes and acrylates or methacrylates, whose graft layer has a glass transition temperature of at least 100° C.,
E) from 0.1 to 5% by weight of at least one copolymer of at least two different esters of acrylic acid or of methacrylic acid or mixtures thereof,
F) from 0 to 25% by weight of at least one halogen-free phosphorus compound and
G) from 0 to 45% by weight of additives,
the sum of components A to G being 100% by weight.
The present invention furthermore relates to the use of these molding materials for the production of moldings, films and fibers, and to the moldings, films and fibers obtainable from the novel molding materials.
Siloxane rubbers are frequently used in polymer blends which contain polycarbonates, in order to improve their toughness. Various siloxane rubbers are used for this purpose. For example, multishell partially crosslinked graft rubbers having an acrylate core and a siloxane shell are used in DE-A 42 38 906. Crosslinked siloxanes may also serve as a grafting base for siloxane graft rubbers (cf. for example EP-A 260 559). Another group of siloxane rubbers comprises the network rubbers, which are also referred to as compound rubbers. The latter differ from graft rubbers in that the siloxane rubber component and at least one further rubber component interpenetrate one another in network form, the rubbers being linked to one another via chemical bonds. These networks may also be provided with one or more graft shells.
EP-A 369 200 disclosed, for example, blends of polycarbonate, styrene/acrylonitrile copolymers and siloxane-based network rubbers. Therein, the network rubber imparts a dull surface to moldings comprising the molding materials. Japanese Preliminary Application 6049313 disclosed molding materials which comprise polycarbonate and siloxane network rubber and have high impact strength.
Polycarbonate/polyester blends containing siloxane network rubber are disclosed in EP-A 307 963. These molding materials contain styrene/acrylonitrile copolymers as a further component and are distinguished by their good low-temperature toughness.
EP-A 641 827 describes readily flowing blends of polycarbonate, acrylonitrile/butadiene/styrene (ABS) and a siloxane-based network rubber. These molding materials may contain small amounts of other polymers, such as vinyl polymers, which are formed as byproducts in the grafting of the siloxane network rubbers.
The known polycarbonate blends which contain siloxane-based network rubbers have the disadvantage that the shaped articles produced therefrom have different total penetration energies, depending on the temperature at which they are molded. This means that the total penetration energy is dependent on the processing conditions, ie. on the respective melt temperature, which has a particularly adverse effect when large shaped articles are to be produced. In the mold, the molding material does not of course always cool uniformly, ie. different values of the total penetration energy are measured at different points of the shaped article.
It is an object of the present invention to provide molding materials which comprise polycarbonate and siloxane network rubbers, and retain the advantages of the known blends, ie. low-temperature toughness and good flow, but can be processed independently of the process conditions.
We have found that this object is achieved by the molding materials defined at the outset. Particular embodiments are described in the subclaims and in the description.
Component A
According to the invention, the molding materials contain, as component A, from 25 to 95.4% by weight, based on the sum of the components A to G, of at least one polycarbonate. Preferred novel molding materials contain from 25 to 88.8% by weight, based on the sum of the components A to G, of component A. Molding materials according to the invention which contain from 27.5 to 86.2% by weight, based on the sum of the components A to G, of component A are particularly preferred.
Preferably used components A are halogen-free polycarbonates. Suitable halogen-free polycarbonates are, for example, those based on diphenols of the general formula II
where A is a single bond, a C
1
-C
3
-alkylene, a C
2
-C
3
-alkylidene, or a C
3
-C
6
-cycloalkylidene group, —S—or —SO
2
—.
Preferred diphenols of the formula II are, for example, hydroquinone, resorcinol, 4,4′-dihydroxybiphenyl,
2,2-bis-(4-hydroxyphenyl)-propane,
2,4-bis-(4-hydroxyphenyl)-2-methylbutane and
1,1-bis-(4-hydroxyphenyl)cyclohexane.
2,2-Bis-(4-hydroxyphenyl)propane and
1,1-bis-(4-hydroxyphenyl)cyclohexane are particularly preferred, as well as 1,1-bis-(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane.
Both homopolycarbonates and copolycarbonates are suitable as component A, the copolycarbonates of bisphenol A being preferred in addition to the bisphenol A homopolymer.
The suitable polycarbonates may be branched in a known manner, preferably by incorporation of from 0.05 to 2.0 mol %, based on the sum of the diphenols used, of at least trifunctional compounds, for example those having three or more than three phenolic OH groups.
Polycarbonates which have proven particularly suitable are those which have relative viscosities &eegr;
rel
of from 1.10 to 1.50, in particular from 1.25 to 1.40. This corresponds to weight average molecular weights M
w
of from 10,000 to 200,000, preferably from 20,000 to 80,000.
The diphenols of the general formula II are known per se or can be prepared by known processes.
The polycarbonates can be prepared, for example, by reacting the diphenols with phosgene by the phase boundary method or with phosgene by the method in the homogeneous phase (ie. the pyridine method), the molecular weight to be established in each case being obtained in a known manner by means of an appropriate amount of known chain terminators. (Regarding polydiorganosiloxane-containing polycarbonates, cf. for example German Laid-Open Application DOS 3,334,782.)
Suitable chain terminators are, for example, phenol and p-tert-butylphenol as well as long-chain alkylphenols, such as 4-(1,3-tetramethylbutyl)phenol, according to German Laid-Open Application DOS 28 42 005, or monoalkylphenols or dialkylphenols having a total of 8 to 20 carbon atoms in the alkyl substituents, according to DE-A 35 06 472, such as p-nonylphenol, 3,5-di-tert-butylphenol, p-tert-octylphenol, p-dodecylphenol, 2-(3,5-dimethylheptyl)phenol and 4-(3,5-dimethylheptyl)phenol.
For the purposes of the present invention, halogen-free polycarbonates mean that the polycarbonates are composed of halogen-free diphenols, halogen-free chain terminators and, if required, halogen-free branching agents, the content of minor ppm amounts of hydrolyzable chlorine, resulting, for example, from the preparation of the polycarbonates with phosgene by the phase boundary method, not being regarded as halogen-containing for the purposes of the present invention. Such polycarbonates containing ppm amounts of hydrolyzable chlorine are halogen-free polycarbonates for t
Guntherberg Norbert
Weber Martin
BASF - Aktiengesellschaft
Keil & Weinkauf
Moore Margaret G.
LandOfFree
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