Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Mixing of two or more solid polymers; mixing of solid...
Patent
1996-11-25
1998-04-28
Mosley, Terressa
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Mixing of two or more solid polymers; mixing of solid...
528176, 528193, 528194, 528196, 528198, C08G 6400
Patent
active
057445540
DESCRIPTION:
BRIEF SUMMARY
The invention relates to polyester/polycarbonate blends having enhanced properties as well as to a process for enhancing the properties of polyester/polycarbonate blends.
Polyester/polycarbonate blends (PES/PC) such as polybutylene terephthalate/PC blends (PBT/PC) or polyethylene terephthalate/polycarbonate blends (PET/PC), or ternary blends such as PBT/PC/ABS, are important engineering plastics. These blends unite the properties of the starting polymers, such as high impact strength at room temperature and at low temperature, high rigidity, low susceptibility to stress-cracking, good resistance to chemicals, in particular to fuel, and easy coatability. Because of these properties, PBT/PC blends are preferably used for lacquered parts of large dimensions, for example in the automotive industry for the production of car bumpers. Since the production of these parts demand relatively long cycle times at elevated temperature, efficient processing stabilisation is essential.
The mechanical and physical properties of these blends furthermore depend essentially on the molecular weight of the polymer. During processing and use, however, the PES/PC blends are often damaged, resulting in reduced molecular weight. High-quality recycling of used PES/PC blends and of production waste therefore makes an increase of the molecular weight necessary.
Accordingly, it is the object of the present invention to provide PES/PC blends, more particularly PBT/PC recyclates, having enhanced properties. In this context, enhancing the properties will be taken to mean in particular enhancing the processing stability and/or increasing the molecular weight. The molecular weight increase may relate either to a single component of the blend or to both or several components of the blend simultaneously.
Surprisingly, a mixture of at least one phosphite, at least one sterically hindered phenol, at least one compound promoting the reaction of an epoxy resin with a PES/PC blend, and at least one difunctional epoxy resin, substantially enhances the properties of the blend.
Accordingly, the invention relates to a PES/PC blend comprising
a) at least one phosphite,
b) at least one sterically hindered phenol,
c) at least one compound promoting the reaction of an epoxy resin with a PES/PC blend,
and d) at least one difunctional epoxy resin, 0.01 to 10 parts of component c) being used per 100 parts of PES/PC blend.
In particular, the present invention relates to PES/PC blend recyclates, more particularly to PBT/PC or PET/PC and, very particularly, to PBT/PC recyclates. Such recyclates originate, for example, from industrial waste or useful material collections, production wastes or obligatory returnables. These recyclates may be obtained, for example, already as blend (for example in the case of car bumper materials), but may also be used as separate polymers for the preparation of the recyclate blend; e.g. PET from bottles and PC from rib-enforced sandwich panels of roof linings, or e.g. from returnable bottles. The recyclates may in particular be recyclates from car bumpers.
Furthermore, according to this invention only one component of the blend can be in the form of scrap material, for example PET bottle recyclate in combination with PC virgin material.
The polyesters may be homopolyesters or copolyesters that are derived from aliphatic, cycloaliphatic or aromatic dicarboxylic acids and diols or hydroxycarboxylic acids.
The aliphatic dicarboxylic acids may contain from 2 to 40 carbon atoms, the cycloaliphatic dicarboxylic acids from 6 to 10 carbon atoms, the aromatic dicarboxylic acids from 8 to 14 carbon atoms, the aliphatic hydroxycarboxylic acids from 2 to 12 carbon atoms, and the aromatic as well as the cycloaliphatic hydroxycarboxylic acids from 7 to 14 carbon atoms.
The aliphatic diols may contain from 2 to 12 carbon atoms, the cycloaliphatic diols from 5 to 8 carbon atoms and the aromatic diols from 6 to 16 carbon atoms.
Aromatic diols will be taken to mean those in which two hydroxyl groups are bonded to one aromatic hydrocarbon radical or
Herbst Heinz
Hoffmann Kurt
Pfaendner Rudolf
Ciba Specialty Chemicals Corporation
Hall Luther A. R.
Kovaleski Michele A.
Malia Victoria M.
Mosley Terressa
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