Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From phosphorus-containing reactant
Reexamination Certificate
2002-08-28
2004-03-30
Truong, Duc (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From phosphorus-containing reactant
C528S397000, C528S400000, C528S425000, C528S480000, C528S494000, C528S495000, C528S503000
Reexamination Certificate
active
06713598
ABSTRACT:
BACKGROUND
The invention relates generally to a process for preparation of a solid polymeric phosphate with linear structure with a softening temperature of at least 10° C. and with less than 10 ppm halogen bound to phosphorus. The invention also relates to resinous compositions comprising said solid polymeric phosphate made by the method.
Polymeric phosphates have been reported. In particular, U.S. Pat. Nos. 2,616,873 and 2,636,876 teach preparation of polymeric phosphates through reaction of monoaryldichlorophosphates with a dihydroxy aromatic compound. However, both methods produce polymeric phosphates which contain residual chlorophosphate which is corrosive to processing equipment and limits the usefulness of the phosphate products. U.S. Pat. Nos. 4,481,338 and 4,482,693 teach preparation of a limited number of polymeric phosphates and their use in resinous compositions. However, the polymeric phosphates taught therein are branched resins and may also contain residual chlorophosphate due to the absence of a final chain-capping step. There is a need for a solid polymeric phosphate flame retardant since solids eliminate the use of liquid handling equipment required for many phosphate flame-retardants during blending operations. More particularly, there is a need for a process which unequivocally leads to linear, solid polymeric phosphate with no possibility of residual halogen-phosphorus linkages which result in corrosion of common resin processing equipment. The present method addresses such a need.
BRIEF DESCRIPTION
In various embodiments the present invention comprises a method for the preparation of a solid polymeric phosphate with a molecular weight of at least about 1500 and a softening temperature of at least about 10° C. comprising the steps of (a) reacting a phosphorus oxyhalide with a monohydroxyaromatic compound to form a monoaryldihalophosphate; (b) removing substantially all of any remaining phosphorus oxyhalide; (c) reacting the monoaryldichlorophosphate product with a dihydroxyaromatic compound; and, (d) reacting the product of step (c) with a monohydroxyaromatic compound wherein the polymer thus formed is a solid with a linear structure and with less than 10 ppm halogen bound to phosphorus.
DETAILED DESCRIPTION
In various embodiments, a solid polymeric phosphate can be prepared by a multi-step process. In the first step, a phosphorus oxyhalide is reacted with a monohydroxyaromatic compound to form a monoaryldihalophosphate. The phosphorus oxyhalide comprises at least one of phosphorus oxychloride or phosphorus oxybromide. In a particular embodiment, the phosphorus oxyhalide comprises phosphorus oxychloride. The amount of phosphorus oxyhalide required can range from about 1 to about 5 times the amount that is stoichiometrically required to complete the reaction with the monohydroxyaromatic compound. In various embodiments, the molar ratio of phosphorus oxyhalide to monohydroxyaromatic compound which can be used in the present method can in one embodiment be about 1:1, in another embodiment about 2:1, in another embodiment about 3:1, in another embodiment about 4:1, and in still another embodiment about 5:1. In some embodiments, the molar ratio of phosphorus oxyhalide to monohydroxyaromatic compound is greater than about 1:1.
Suitable monohydroxyaromatic compounds comprise those derived from monocyclic or polycyclic aromatic moieties, which may be substituted or unsubstituted. In one embodiment a monocyclic aromatic moiety comprises phenyl. Polycyclic aromatic moieties which may serve as the source of monohydroxyaromatic compounds include fused ring species such as naphthalene and monocyclic aromatic moieties linked by a covalent bond, as for example in biphenyl, or linked by at least one linking atom, such as alkylene, alkylidene, carbonyl, oxygen, nitrogen, sulfur, sulfoxide, sulfone, phosphorus or silicon. In various embodiments, substituents on monohydroxyaromatic compounds, when present, include at least one C
1
-C
30
alkyl, which may be normal, branched, cyclic, or bicyclic, or at least one halogen group. In particular embodiments monohydroxyaromatic compounds that can be used include phenol, ortho-cresol, meta-cresol, para-cresol, xylenol, 2,6-xylenol, 2,4-xylenol, 2,3-xylenol, 2,5-xylenol, 3,4-xylenol, 3,5-xylenol, 2-bromophenol, 3-bromophenol, 4-bromophenol, 2,3-dibromophenol, 2,6-dibromophenol, 2,4-dibromophenol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2,6-dichlorophenol, 2,4-dichlorophenol, 2,3-dichlorophenol, 2,5-dichlorophenol, 3,4-dichlorophenol, and 3,5-dichlorophenol. Monohydroxyaromatic compounds with at least one alkyl substituent and at least one halogen substituent are also suitable.
In various embodiments the reaction is performed at a temperature suitable for the monohydroxyaromatic compound to react with the phosphorus oxyhalide. In some embodiments monohydroxyaromatic compounds with ortho substituents may require a higher temperature than those with para or meta substituents. In particular embodiments the temperature range for reacting monohydroxyaromatic compound with phosphorus oxyhalide is between about 100° C. and 200° C. In various embodiments, the reaction temperature may be held in the desired range for a sufficient period of time such that essentially all the monohydroxyaromatic compound in the reaction mixture has reacted. Analytical methods for monitoring the concentration of monohydroxyaromatic compound in the reaction mixture are well known to those skilled in the art, and may be applied as appropriate depending upon the degree of accuracy desired. Reaction of essentially all the monohydroxyaromatic compound in the present context means that in one embodiment, greater than about 95 mole % of the monohydroxyaromatic compound has reacted; in another embodiment, greater than about 98 mole % of the monohydroxyaromatic compound has reacted; and in another embodiment, greater than about 99 mole % of the monohydroxyaromatic compound has reacted. In a particular embodiment, reaction of essentially all the monohydroxyaromatic compound in the present context means that none can be detected using the chosen analytical method. In some embodiments, the reaction temperature may be held essentially constant in the desired range for the necessary period of time. One of average skill in the art should recognize that the time and temperature of the first step may vary with such factors as the substituent in the monohydroxyaromatic compound and also on the type and amount of phosphorus oxyhalide used, among other factors. In some particular embodiments, the monohydroxyaromatic compound is added slowly to the phosphorus oxyhalide. A slow addition tends to minimize formation of triaryl phosphates. The time of addition of monohydroxyaromatic compound to phosphorus oxyhalide is in some particular embodiments greater than about 1 hour, in other particular embodiments greater than about 2 hours, in still other particular embodiments greater than about 3 hours, and in still other particular embodiments greater than about 5 hours. In another embodiment the time of addition of monohydroxyaromatic compound to phosphorus oxyhalide is in a range of between about 1 hour and the total time required for essentially all of the monohydroxyaromatic compound to react with the phosphorus oxyhalide. In still another particular embodiment the time of addition of monohydroxyaromatic compound to phosphorus oxyhalide is in a range of between about 1 hour and about 15 hours. In other particular embodiments, all of the phosphorus oxyhalide is added in one batch. The total reaction time of the monohydroxyaromatic compound with the phosphorus oxyhalide is in some particular embodiments greater than about 1 hour, in other particular embodiments greater than about 2 hours, in still other particular embodiments greater than about 3 hours, and in still other particular embodiments greater than about 5 hours. In another particular embodiment, the total reaction time of monohydroxyaromatic compound with phosphorus oxyhalide is in a range of between about 1 hour and ab
de Wit Gerrit
Gosens Jan
Selvaraj Immanuel I.
General Electric Company
Truong Duc
LandOfFree
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