Synthesis and use of amine molybdates

Details Synthesis and use of amine molybdates Synthesis and use of amine molybdates

2000-04-11

2001-04-17

Nazario-Gonzalez, Porfirio (Department: 1621)

Compositions

Fire retarding

For solid synthetic polymer and reactants thereof

C544S181000, C556S057000

Reexamination Certificate

active

06217797

ABSTRACT:

BACKGROUND OF THE INVENTION
Vinyl chloride and vinylidene chloride polymers are known to be self-extinguishing and relatively more flame retardant than other polymers such as polyethylene, polypropylene and the like. However, a substantial amount of smoke may be produced upon exposure of vinyl chloride and vinylidene chloride polymers to a flame. The fact that an additive is a flame retardant does not necessarily mean that it will have good smoke retardant properties.
Inorganic and organometallic complexes of molybdenum are commercially useful as smoke suppressants in halogenated resins. Various amine molybdates have been investigated by B. F. Goodrich, see U.S. Pat. No. 4,153,792, for smoke suppression in PVC compounds. These compounds were plagued with poor performance properties due to residual molybdenum trioxide. The residual MoO
3
causes blue discoloration of the resin systems coupled with poor thermal stability.
The most commercially recognized material for smoke suppression in PVC is ammonium octamolybdate (AOM). AOM is the premium material to make low smoke PVC compounds, particularly for plenum wire and cable applications. AOM is used in numerous PVC jacket formulations that pass the rigorous UL910 test for cables (cooper conductor and fiber optic cables).
U.S. Pat. No. 4,153,792 discloses the production of amine molybdates, especially melamine molybdate by reacting an amine, such as melamine, with molybdenum trioxide in an aqueous acidic medium under reflux.
U.S. Pat. No. 4,217,292 discloses the production of amine molybdates, preferably melamine molybdate by reacting an amine such as melamine with a stoichiometric quantity of molybdenum trioxide in an aqueous medium in the presence of an ammonium salt. The aqueous medium is essentially free of acid. The reaction may be conducted at temperatures within the range of 75-110° C.
SUMMARY OF THE INVENTION
It has now been discovered that an amine molybdate which contains no residual molybdenum trioxide may be prepared by reacting an amine, preferably melamine, with molybdenum trioxide in an acidic aqueous medium under greater than atmospheric pressure and at a temperature of from 105-150° C. The reaction is conducted for a time sufficient to eliminate all detectable amounts of molybdenum trioxide. The resultant salts are highly effective as smoke retardants in vinyl chloride and vinylidene chloride polymers and in fluoropolymers. These salts are a snow white powder which do not discolor the halogenated resins when they are compounded with such resins. In contrast, the prior art salts are blue to gray tinted and this color is imparted to the compounded chlorinated resin.
DETAILED DESCRIPTION OF THE INVENTION
Amine molybdates are produced in accordance with this invention by reacting essentially stoichiometric quantities of molybdenum trioxide with an amine in an aqueous acidic medium, preferably containing a water soluble ammonium salt of a monovalent or divalent acid. The reaction is conducted at a temperature of 105-150° C., and, preferably, at a temperature of 115-150° C. under a pressure of up to 6 bar. Preferably, the pH of the reaction mixture is within the range of 5-7.
Amines suitable for preparing the amine molybdates using the process of this invention include polymeric amines, as well as simple amines. The simple amines may contain from 1 to 75 carbon atoms and from 1 to 10 primary, secondary, or tertiary amine groups or a mixture thereof, more preferably from 1 to 6 groups. Simple amines include aliphatic, alicyclic, aromatic and heterocyclic amines. Examples of suitable polymeric amines include polyethyleneimine, polyvinylpyridine, polyvinylpyrroilidine and poly(2,24-trimethyl-1,2-dihydroquinolyl). Examples of suitably simple amines include aliphatic amines such as ethylamine, ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 2-methyl- 1,2-propanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,10-decanediamine, 1,12-dodecanediamine, and the like. Also suitable are aliphatic amines such as diethylenetriamine, triethylenetetramine, tetraethylene-pentamine, bis(hexamethylene)triamine, 3,3′-iminobispropylamine, guanidine carbonate, and the like. Other suitable amines include alicyclic diamines and polyamines such as 1,2-diaminocyclohexane, 1,8-p-menthanediamine, and the like, aromatic amines such as aniline, N,N-dimethylaniline, and the like, and heterocyclic amines such as melamine and substituted melamines, ammeline, pyridene, piperazine, hexamethylenetetramine, 2,2,4-trimethyldecahydroquinoline, and N-(aminoalkyl)-piperazines wherein each alkyl group contains from 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, such as N-(2-aminoethyl)-piperazine and the like.
The amine molybdates of this invention are useful as smoke suppressants in vinyl halide resins (PVC, PVDF, PTFE, PVDC, CPVC, and ECTFE resins), by a reductive coupling mechanism which induces char formation.


REFERENCES:
patent: 4053455 (1977-10-01), Kroenke
patent: 4153792 (1979-05-01), Kroenke
patent: 4217292 (1980-08-01), Kroenke

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