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...
Reexamination Certificate
1997-03-13
2001-06-05
Dawson, Robert (Department: 1712)
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...
C523S210000, C524S405000, C524S417000, C524S424000, C524S430000, C524S437000
Reexamination Certificate
active
06242520
ABSTRACT:
FIELD OF THE INVENTION
The instant invention is directed to polymer compositions. The polymer compositions comprise coated boron phosphate compositions and they unexpectedly display flame retardant properties without creating environmental hazards.
BACKGROUND OF THE INVENTION
Compositions which comprise polyphenylene sulfides, polyamides and/or polyphenylene ethers (PPE), for instance, constitute an invaluable class of engineering materials. Materials of such are characterized by a unique combination of chemical, physical and electrical properties. For instance, they are resistant to many solvents and generally have high impact strengths. As a result of this unique combination of properties, polyphenylene ethers, polyphenylene sulfides and polyamide materials are suitable for a broad range of commercial applications.
Moreover, as a result of said properties, and particularly their characteristic dimensional stability and dielectric properties, it has been of increasing interest to prepare materials of the above-described which also display flame retardant properties. The flame retardant properties are typically obtained by employing additives such as halogenated compounds, antimony containing compounds and/or red phosphorus which invariably create severe environmental hazards. Moreover, attempts have been made to use salt additives; however, their hydrolytic instability proved them to be ineffective.
This invention, however, is directed to polymer compositions which comprise coated boron phosphate compositions and they unexpectedly display hydrolytic stability and flame retardant properties without creating environmental hazards.
DESCRIPTION OF THE PRIOR ART
Efforts have been disclosed for producing polymer compositions. In U.S. Pat. No. 5,043,369, glass/glass-ceramic-plastic alloy articles are described.
Other attempts have been made to prepare polymer compositions. In U.S. Pat. No. 4,544,695, polymeric flame retardant compositions comprising phosphate-sulfate glass compositions are described.
Still other investigators have focused on the production of polymer compositions. In U.S. Pat. No 4,079,022, fire retardant resin compositions containing moisture resistant low melting phosphate glass is described.
SUMMARY OF THE INVENTION
The instant invention is directed to a composition comprising:
(a) an additive comprising a core and a metal compound coating wherein said core comprises boron phosphate and said metal ion coating comprises at least one metal selected from the members consisting of Group IIA, IIB, IIIB, IVB, VIIB and VII metals;
(b) polysiloxanes; and
(c) a polymer system selected from the group consisting of immiscible polymer blends, miscible polymer blends, copolymers, thermoplastic polymers and thermosetting polymers.
The Group IIA, IIB, IIIB, IVB, VIIB and VII metals are according to the CAS version of the Periodic Table of the Elements as set forth in the
Handbook of Chemistry and Physics,
93rd Edition, 1992-1993.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The boron phosphate core of the additive employed in this invention is often commercially available. Additionally, it may be prepared by mixing, for example, hydrated boric acid and phosphoric acid followed by heating the resulting mixture to a calcining temperature.
The coating, typically a metal borate or a metal phosphate, surrounding the boron phosphate core is prepared by first forming a boron phosphate slurry and adding to the slurry a salt of the metals described in (a). The salts are often added in the form of carboxylate, carbonate, halide, oxide, hydroxide or alkoxide; however, any form of salt capable of resulting in a metal ion coating may be employed. The salts are added to the slurry to the point where interactions are made between the metal cation of the salt and the resulting borate and phosphate ions generated in the slurry.
It is noted herein that not all of the boron phosphate ionizes. In fact, the slurry is prepared only to the extent of generating active sites on the surface of the boron phosphate core. The metal ion coating surrounding the core is not limited to any thickness. However, its thickness is typically enough to enhance the hydrolytic stability of the core without sacrificing its flame retardant properties.
The thickness of the coating, therefore, is often from about a monoatomic layer to about 1.5 microns and preferably from about a monoatomic layer to 1.0 micron thick and most preferably from about 0.02 microns to 0.15 microns. Such a coating prevents boron phosphate ionization by creating a neutralized outer layer which is insensitive to water, allowing the flame retardant properties of the hydrolytically unstable core to predominate.
Often, the preferred salts employed in this invention are those which comprise a titanium, magnesium, calcium, barium, aluminum or zinc cation.
There is essentially no limitation with respect to the polysiloxanes employed in this invention. They include polysiloxanes and siloxane copolymers such as polyphenylene ether and polyetherimide copolymers. The preferred polysiloxanes are commercially available and often represented by the formula
wherein each R
1
is independently a C
1-5
alkyl group and preferably a methyl group and R
2
is a C
1-5
alkyl group or a primary or secondary aminoalkyl group such as a N-(2-aminoalkyl)-3-aminoalkyl group, provided that R
2
is a C
1-5
alkyl group when w is 1 and a N-(2-aminoalkyl)-3-aminoalkyl group when w is 0. It is often preferred that R
2
is a methyl group or a N-(2-aminoethyl)-3-aminopropyl group. R
3
is hydrogen or a C
1-5
alkyl group, preferably a methyl group. w is 0 or 1 and x and y are each independently an integer from 1 to 7 and z is an integer from 0 to 7. It is noted herein that any combination of compounds represented by formula I may be employed.
It is also within the scope of the invention to employ polysiloxanes represented by the formulae
wherein m+n has a value of 5-2000, A
1
-A
15
, each independently of each other, represent a hydrogen atom or one of the following groups having 1-12 carbon atoms: alkyl, alkoxy, alkenyl, aryl, aralkyl, alkylaryl, which groups may be halogenated; wherein X
1
, X
2
, X
3
, each independently of each other, represent one of the following groups: alkylene, cycloalkylene, arylene, aralkylene, alkylarylene; wherein Z
1
, Z
2
, Z
3
each represent one of the following groups: —NA
16
A
17
, —NH—(CH
2
)
q
—NA
16
A
17
in which q has a value of 1-10 and A
16
and A
17
, each independently of each other, represent a hydrogen atom or an alkyl group having 1-12 carbon atoms, an aliphatic or cycloaliphatic epoxide, a carboxylic acid or anhydride group, Z
1
or Z
2
is a hydrogen atom, in which, however, the compound of formula II may not comprise simultaneously an amine group and an epoxide group or not simultaneously an amino group and a carboxylic acid group, or not simultaneously an epoxide group and a carboxylic acid or anhydride group.
The amount of polysiloxane in the composition is not limited. It is often no more than about 20% by weight and preferably no more than about 5.0% by weight and most preferably no more than about 2.0% by weight based on total weight of the second metal composition.
There is no limitation with respect to the immiscible polymer blends, miscible polymer blends, copolymers, thermoplastic polymers or thermosetting polymers (hereinafter all referred to as polymer systems) employed in this invention other than that they are able to form a composition with the members in (a) and (b) as described above. Illustrative examples of the polymer systems that may be employed in this invention include any of those, for instance, which comprise polyphenylene ethers in combination with polyolefins, polyamides, polyarylene sulfides, polyesters, acrylonitrile butadiene styrene copolymers, polystyrenes or polyetherimides. Polycarbonates in combination with polyesters like poly(butylene terephthalate) or a terpolymer like acrylonitrile butadiene styrene may also be employed. The preferred thermoplastic polymers employed in this inven
Shaw Jeremy Paul
Venkataramani Venkat Subramaniam
Dawson Robert
General Electric Company
Johnson Noreen C.
Stoner Douglas E.
Zimmer Marc S.
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