Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1985-05-03
1987-08-11
Hoke, Veronica P.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
2524003, 524303, 524320, 524356, 524450, C08K 537, C08K 534
Patent
active
046862552
DESCRIPTION:
BRIEF SUMMARY
The invention pertains to stabilized thermoplastic molding compositions on the basis of polyvinyl chloride or essentially vinyl chloride-containing polymers.
In the molding of thermoplastic polymers into pipes, bottles, profiles, films, and the like, for example by extrusion, injection molding, blowing, deep drawing and calandering, degradation of the plastic can easily take place at the high temperatures thus occurring. This leads to undesirable discolorations and a reduction of the mechanical properties. For this reason stabilizers are added to the polymers prior to thermal deformation to prevent such degradation. Thermal stabilizers used for polyvinyl chloride and essentially vinyl chloride-containing mixed polymers principally include inorganic and organic lead salts, organic antimony compounds, organotin compounds, as well as cadmium/barium carboxylates and phenolates. The metal compounds mentioned are usually designated as primary stabilizers; to improve their efficacy, secondary stabilizers or costabilizers are frequently added to them. Further details regarding the thermal stabilizers customarily employed for vinyl chloride polymers can be taken from the relevant literature, for example the Encyclopedia of Polymer Science and Technology, Vol. 12, New York, London, Sydney, Toronto 1970, pp. 737 to 768.
In practice the stabilizers mentioned show completely satisfactory effects. However, certain objections exist against the use of lead, antimony and cadmium compounds, especially from the toxicologic viewpoint. A number of organotin compounds are pathologically safe, but broader use of these is impeded by their high price. For this reason attempts have long been made to replace these compounds with safer and less expensive substances. In this connection a change was made to using as the primary stabilizers fatty acid salts of aromatic carboxylates and phenolates of the metals calcium, barium, zinc and aluminum, possibly supplemented by costabilizers, e.g., organic phosphites, imino compounds, epoxy compounds, polyvalent alcohols or 1,3-diketones. However, these newer stabilizer systems involve to a greater or lesser degree the defect that they impart inadequate initial stability and/or inadequate long term stability to the molding compositions to be stabilized. Therefore a need exists for substances with the aid of which the initial and/or long term effect of such stabilizers can be decisively improved.
It was found that alkali salts of 2-oxo- and 3-oxo-carboxylic acids can be successfully employed to stabilize polyvinyl chloride molding compositions. In particular it was found that these salts of oxocarboxylic acids are able to increase the stabilizing action, especially the long term effect of primary stabilizers on the basis of soaps, aromatic carboxylates and phenolates of the metals calcium, barium, zinc and aluminum as well as of organotin compounds to an unexpected degree.
Thus the subject of the invention comprises stabilized polyvinyl chloride molding compositions containing compounds of Formula I ##STR2## in which R represents an alkyl group with 1 to 19 carbon atoms, a cycloalkyl group with 5 or 6 carbon atoms, a phenyl group, an alkylphenyl group with 7 to 11 carbon atoms, or an MOOC--CH.sub.2 group, n represents the numbers 0 or 1, and M represents lithium, sodium or potassium.
In particular the object of the invention comprises stabilized molding compositions which contain a stabilizer combination consisting of (1) primary stabilizers selected from the group consisting of metal soaps, aromatic metal carboxylates, metal phenolates, and organotin compounds, and (2) compounds of Formula I as costabilizers as well as the usual lubricants and possibly other processing aids.
Additional objects of the invention include stabilizer combinations for polyvinyl chloride molding compositions containing primary stabilizers selected from the group consisting of metal soaps, aromatic metal carboxylates, metal phenolates and organotin compounds and compounds of Formula I as costabilizers, the usual lubric
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Erwied Werner
Upadek Horst
Wegemund Bernd
Grandmaison Real J.
Greenfield Mark A.
Henkel Kommanditgesellschaft auf Aktien
Hoke Veronica P.
Millson Henry E.
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