Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – At least one aryl ring which is part of a fused or bridged...
Patent
1986-10-14
1988-07-12
Pertilla, Theodore E.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
At least one aryl ring which is part of a fused or bridged...
524504, 524548, 525 64, 525 66, 525 67, 525 68, 525 73, C08L 3904, C08L 5100
Patent
active
047571098
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a process for the preparation of maleimide copolymers having excellent thermal resistance, and resistance to thermal decomposition, as well as to a thermoplastic resin composition using the same and having excellent thermal resistance, resistance to thermal decomposition, and impact resistance.
PRIOR ART
In recent years, the demand for improved thermal resistance of materials for automobile parts has grown. In particular for the manufacture of interior trim parts such as meter hoods, meter clusters, instrument panels and console boxes, and of exterior trim parts such as bumpers, outer panels and lamp housings, a material having high thermal resistance, good moldability, and not subject to thermal decomposition and thermal discoloration is in demand.
Conventionally, heat-resistant ABS resins, modified polyphenylene ether (modified PPO) resins, polycarbonate (PC) resins and similar resins have been used for the manufacture of automobile parts requiring thermal resistance.
Heat-resistant ABS resins are prepared by the so-called graft blending of (i) a grafted ABS resin formed by grafting acrylonitrile and styrene and/or .alpha.-methylstyrene onto a diene rubber and (ii) a resin formed by the copolymerization of acrylonitrile with styrene and/or .alpha.-methylstyrene. In the existing circumstances, however, the resulting heat-resistant ABS resins fail to exhibit satisfactorily high thermal resistance because of the inadequate thermal resistance of the copolymer resin (ii) used. Although highly heat-resistant resins can be obtained by increasing the .alpha.-methylstyrene content of this copolymer resin (ii), copolymer resins (ii) having such a high .alpha.-methylstyrene content are disadvantageous in that resins having a high degree of polymerization cannot be obtained because of their low polymerization rate and in that they are subject to thermal decomposition during molding because of their structure including .alpha.-methylstyrene chains connected to each other.
On the other hand, modified PPO resins and PC resins or their modified products generally have the disadvantage of being expensive and poor in moldability. Accordingly, there is a great need to develop a thermoplastic resin composition that is inexpensive, undergoes almost no thermal decomposition, can be molded easily, and has adequately high thermal resistance.
It is already known that maleimide monomers of the formula ##STR1## where R is a hydrogen atom, an alkyl group of 1 to 4 carbon atoms, a cyclohexyl group, an aryl group or a substituted aryl group, can readily copolymerize with vinyl monomers, such as styrene, acrylonitrile or methyl methacrylate to form copolymers which have high thermal resistance but are very brittle.
The polymerization techniques whereby highly heat-resistant resins can be prepared from maleimide monomers include solution polymerization, bulk polymerization, spension polymerization, emulsion polymerization and the like. However, from the viewpoint of uniformity characteristics such as the compositional distribution of each component in the copolymer and the distribution of polymerization degree, emulsion polymerization is considered to be suitable. Moreover, from the viewpoint of moldability, impact resistance and thermal resistance, it is expected that a desirable combination of properties are obtained in copolymers formed by copolymerizing a maleimide monomer with an aromatic vinyl monomer, a vinyl cyanide monomer and the like.
However, if an aromatic vinyl monomer, a vinyl cyanide monomer and a maleimide monomer are subjected to emulsion polymerization with a view to preparing a copolymer having high thermal resistance and resisting thermal decomposition and thermal discoloration, a copolymer having low polymer yield and low thermal resistance and exhibiting poor impact resistance only will be obtained if the total amount of the monomer mixture is simply charged into the polymerization system at one time and the polymerization is then initiated. The reason for this may be
REFERENCES:
patent: 2971939 (1961-02-01), Baer
Abstract: 84-228087/37, "Heat Resistant Thermoplastic Resin Production", (J59135210).
Kimura Atsushi
Kishida Kazuo
Toyooka Yutaka
Mitsubishi Rayon Co. Ltd.
Pertilla Theodore E.
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