Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
1999-07-07
2002-07-02
Hoke, Veronica P. (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S121000
Reexamination Certificate
active
06414060
ABSTRACT:
BACKGROUND
Thermoplastic polymer compositions or alloys made by blending together polycarbonate polymer and ABS polymer (PC/ABS) are materials of industrial importance. In order to flame retard such compositions, a number of stringent requirements must be satisfied. Besides being halogen-free and suitably effect in retarding flame, the flame retardant should have a high heat distortion temperature, and a high softening temperature. Thus, even in the absence of an anti-dripping agent such as a Teflon® polymer, the flame retardant should exhibit at least a V-2 rating when test samples are subjected to the UL-94 test procedure. The flame retardant itself should be thermally stable at temperatures of at least about 260° C. and preferably above 260° C., and should not contribute materially to discoloration of the finished polymer composition, especially during exposure to molding or extrusion temperatures. In addition, the flame retardant should not be prohibitively expensive to produce.
In an attempt to provide flame retardants satisfying these requirements, many different phosphorus additives were synthesized and evaluated. Many of the samples failed to meet the thermal stability requirement or decomposed on processing with the PC/ABS.
SUMMARY OF THE INVENTION
Pursuant to this invention certain halogen-free phosphoramidate compounds have been found to satisfy the foregoing requirements. The phosphoramidates used pursuant to this invention are of three types, namely, (I) O,O-diaryl-N-arylphosphoramidates, (II) arylene-N,N′-bis(O,O-diarylphosphoramidates) in which the nitrogen atoms are in the 1,3 or 1,4 positions on an arylene ring, and (III) N,N′-piperazinediylbis(O,O-diarylphosphoramidates).
Thus this invention provides in one of its embodiments a flame retardant polymer composition which comprises a blend made from (i) a polycarbonate-ABS polymer composition, and a flame retardant amount of (ii) at least one halogen-free phosphoramidate selected from (I) O,O-diaryl-N-arylphosphoramidates, (II) arylene-N,N′-bis(O,O-diarylphosphoramidates) in which the nitrogen atoms are in the 1,3 or 1,4 positions on an arylene ring, and (III) N,N′-piperazinediylbis(O,O-diarylphosphoramidates).
Another embodiment is the method of rendering a PC/ABS polymer composition flame retardant which comprises blending with such composition a flame retardant amount of at least one halogen-free phosphoramidate flame retardant selected from (I) O,O-diaryl-N-arylphosphoramidates, (II) arylene-N,N′-bis(O,O-diarylphosphoramidates) in which the nitrogen atoms are in the 1,3 or 1,4 positions on an arylene ring, and (III) N,N′-piperazinediylbis(O,O-diarylphosphoramidates).
The above phosphoramidates can be depicted by the following formulas:
(RO)
2
P(O)(NHR) (I)
[(RO)
2
P(O)NH—]
2
Ar (II)
[(RO)
2
P(O)—]
2
Z (III)
where each R is the same or different and is an aryl group, Ar is an arylene group that is bonded in its 1,3- or 1,4-positions to the respective depicted nitrogen atoms, and Z is the piperazinediyl group. Each R group typically contains in the range of 6 to about 18 carbon atoms, examples of which include phenyl, tolyl, ethylphenyl, xylyl, mesityl, biphenylyl, naphthyl, methylnaphthyl, 4-dimethylaminophenyl, and 4-methoxyphenyl. Preferably each R is a hydrocarbyl aryl group (i.e., it consists of carbon and hydrogen atoms), and preferably each R is a monocyclic aryl group having in the range of 6 to 14, and more preferably in the range of 6 to 10 carbon atoms. Most preferably each R group is phenyl.
The flame retardants of this invention are effective in the absence of flame retardant auxiliaries such as (1) antimony-based synergists, (2) halogen-containing flame retardants, and (3) sulfur or sulfur-containing flame retardant auxiliaries. Indeed, it is preferred to use the phosphoramidates of this invention in the absence of any of these three types of flame retardant auxiliary additives.
In one of its embodiments this invention a flame retardant polymer composition which comprises a blend made from PC/ABS, and a flame retardant amount in the range of about 5 to about 30 wt % (preferably in the range of about 10 to about 20 wt %) of at least one halogen-free phosphoramidate described above. Unless otherwise specified, all weight percentages of phosphoramidate given in this document are based on the total weight of the substrate polymer plus phosphoramidate.
In another embodiment, the above PC/ABS substrate polymer and phosphoramidate flame retardant are in the form of a powder blend or master batch wherein the composition contains a higher concentration of the phosphoramidate than the particular concentration to be used in the finished polymer composition. Thus such powder blend or master batch can contain up to about 99 wt % of the phosphoramidate, but normally will contain in the range of about 20 to about 60 wt % phosphoramidate. Such compositions are mixed with additional substrate polymer when producing the molded or extruded article or shape.
In connection with blends that are or are to be molded or extruded (i.e., expressed through a die) without further dilution with substrate polymer, the term “flame retardant amount” as used herein, including the claims hereof, means that the amount of phosphoramidate used in forming the composition is at least the minimum amount in the range of about 5 to about 30 wt % needed with the particular substrate polymer with which the phosphoramidate is blended to enable molded test specimens made from the resultant blend to exhibit at least a V-2 rating in the UL-94 test procedure. More than such minimum amount of phosphoramidate relative to the amount of polymer can be used in these situations and be considered a flame retardant amount, provided that the weight ratio of phosphoramidate to polymer is in the range of about 5 to about 30 wt %. On the other hand, in connection with master batch blends or powder preblends that are prepared for future dilution with additional substrate polymer preparatory to making finished molded, extruded or foamed shapes or objects (articles), any amount of phosphoramidate that is above the minimum “flame retardant amount” can be used.
Other embodiments of the invention will be still further apparent from the ensuing description and the appended claims.
FURTHER DETAILED DESCRIPTION
The phosphoramidates used in the practice of this invention are composed of three groups. One group is composed of O,O-diaryl-N-arylphosphoramidates, compounds of the above formula (I).
The second and third groups are depicted by formulas (II) and (III), respectively. While the aryl groups of all three such groups are most preferably unsubstituted phenyl groups, one or more of them can be substituted with up to 5 hydrocarbyl substituents, e.g., alkyl, alkenyl, cycloalkyl, cycloalkenyl, cycloalkylalkyl, aryl, aralkyl, or one or more non-halogen containing functional substituents such as alkoxy, dialkylamino, nitro, cyano, carboxylic, esterified carboxylic, or like innocuous substituent, or a combination of hydrocarbyl and such functional substituent(s). A few non-limiting examples of formula (I) phosphoramidates include ditolyl-N-phenylphosphoramidate, ditolyl-N-tolylphosphoramidate, diphenyl-N-xylylphosphoramidate, di(ethylphenyl)-N-(p-propylphenyl)phosphoramidate, diphenyl-N-(2,4,6-trimethylphenyl)phosphoramidate, diphenyl-N-(m-nitrophenyl)phosphoramidate, and diphenyl-N-(p-biphenylyl)phosphoramidate. Of the formula (I) phosphoramidates, diphenyl-N-phenylphosphoramidate is most preferred.
The arylene group of the Group II phosphoramidates can be a phenylene, naphthalene, dihydronaphthalene, or tetrahydronaphthalene group in which the univalent bonds to the respective nitrogen atoms are in the 1,3- or 1,4-positions of the phenylene group of such arylene groups. The arylene group can be unsubstituted or substituted with hydrocarbyl substituents, e.g., alkyl, alkenyl, cycloalkyl, cycloalkenyl, cycloalkylalkyl, aryl, aralkyl, and/or one or more non-halogen containing functi
Beltz Mark W.
Kumar Govindarajulu
McEuen John M.
Albemarle Corporation
Hoke Veronica P.
Spielman, Jr. E. E.
LandOfFree
Flame retardant polycarbonate-ABS polymer compositions does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Flame retardant polycarbonate-ABS polymer compositions, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Flame retardant polycarbonate-ABS polymer compositions will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2886482