Organic compounds -- part of the class 532-570 series – Organic compounds – Phosphorus esters
Reexamination Certificate
2002-05-03
2003-08-12
McKane, Joseph K. (Department: 1628)
Organic compounds -- part of the class 532-570 series
Organic compounds
Phosphorus esters
C568S700000
Reexamination Certificate
active
06605737
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a method for preparing a condensed phosphoric ester. More specifically, the present invention relates to a method for preparing a condensed phosphoric ester which has a low content of volatile components that cause an adverse influence in the quality of resins, and which is excellent as an additive for resins, such as a plasticizer, a flame retardant, or the like.
BACKGROUND ART
Conventional Art
Conventionally, various types of flame retardants are used for flame retardation of inflammable plastic materials, for example, halogen compounds such as decabromobiphenylether and tetrabromobisphenol A, and low molecular weight phosphorus compounds such as cresyl diphenyl phosphate and triphenyl phosphate.
Today, resin compositions are required to be non-halogenic from an environmental point of view, for example, due to the hazardous effects of dioxin. Flame retardants containing heavy metals cause problems due to their toxicity. Under these circumstances, phosphorus-based flame retardants have now become a target of attention. Among the phosphorus-based flame retardants, aromatic phosphoric ester-based flame retardants are a target of attention for their effectiveness especially in the applications of engineering plastics such as PC/ABS alloys and modified PPE since they have little adverse influence on the environment as well as superb physical properties. Actually, the industrial demand for phosphorus-based flame retardants, especially aromatic phosphoric ester-based flame retardants, is good and continues to increase at a high rate.
However, engineering plastics are molded at a very high temperature and therefore the following problems have occurred. When a low molecular weight monomer-type phosphoric ester such as triphenyl phosphate (TPP) or tricresyl phosphate (TCP) is used, the monomer-type phosphoric ester is thermally decomposed, bleeds out or volatizes during the molding process, which causes defective molding, contamination of the molds or the like.
It is known that use of a high molecular weight condensed phosphoric ester as a flame retardant is effective for avoiding these problems. Especially, it is known that use of a condensed phosphoric ester, which has a low content of a low molecular weight monomer-type phosphoric ester, as a flame retardant is effective for avoiding these problems.
In general, a condensed phosphoric ester is prepared by reacting phosphorus oxychloride with a divalent hydroxy compound, such as hydroquinone, resorcin, bisphenol A, or the like, and a monovalent hydroxy compound, such as phenol, cresol, or the like.
However, in the case of a condensed phosphoric ester prepared by a conventional method using a bisphenol A derivative as the divalent hydroxy compound, the following problems have been pointed out. When such a condensed phosphoric ester is mixed with a resin, a molded product is colored, and heat resistance and moldability are adversely influenced.
Problems to be Solved by the Invention
An objective of the present invention is to solve the above-described problems. That is, an objective of the present invention is to provide a method for preparing a condensed phosphoric ester formed from a bisphenol A derivative as a starting material, which does not give a color on a molded product or adversely influence heat resistance and moldability even when mixed with a resin. Another objective of the present invention is to enhance the quality of resin-molded products by using the condensed phosphoric ester produced by a method according to the present invention as a flame retardant, so as to make a contribution to the society.
DISCLOSURE OF THE INVENTION
Means for Solving the Problems
As a result of active studies, the present inventors found that, in a reaction of a bisphenol A derivative with a phosphorus oxytrihalide and a hydroxy compound, the bisphenol A derivative comes into contact with hydrogen halide generated in the reaction with the bisphenol A derivative so as to decompose the bisphenol A derivative, whereby generation of an aryl group-containing phosphate and an isopropenyl aryl group-containing phosphate (monomer-type phosphoric ester) is caused. The present inventors further found that, when the above reaction occurs in the presence of a decomposition retardant, generation of monomer-type phosphoric ester is suppressed, whereby the above-described problems can be solved. Thus, the present inventors completed the present invention.
It should be noted that, in the present specification, an isopropenyl aryl group-containing phosphate is abbreviated as an “IPP”.
Specifically, a method for preparing a condensed phosphoric ester according to the present invention includes a process of reacting a bisphenol A derivative, a phosphorus oxytrihalide, and a hydroxy compound in the presence of a decomposition retardant.
In one embodiment, the decomposition retardant is an organic carboxylic acid-based compound.
In one embodiment, the organic carboxylic acid-based compound is ascorbic acid or adipic acid.
In one embodiment, the decomposition retardant is an oxide or chloride of tin, copper, or iron.
In one embodiment, the oxide or chloride of tin, copper, or iron is a stannic oxide, a ferric chloride, or a cupric chloride.
In one embodiment, the amount of the decomposition retardant used is 0.01-5 parts by weight with respect to 100 parts by weight of the bisphenol A derivative.
In one embodiment, the process of reacting a bisphenol A derivative, a phosphorus oxytrihalide, and a hydroxy compound includes:
a first step of reacting the bisphenol A derivative and the phosphorus oxytrihalide so as to produce a phosphorohalidate; and
a second step of reacting the phosphorohalidate and the hydroxy compound.
In one embodiment, the process of reacting a bisphenol A derivative, a phosphorus oxytrihalide, and a hydroxy compound includes:
a first step of reacting the bisphenol A derivative and the phosphorus oxytrihalide so as to produce a phosphorohalidate, and removing unreacted phosphorus oxytrihalide from a reaction product; and
a second step of reacting the phosphorohalidate and the hydroxy compound.
In one embodiment, the amount of the hydroxy compound used is greater by equal to or less than 2 mol % than an amount which is theoretically necessary for turning the entire amount of the phosphorohalidate into a condensed phosphoric ester.
In one embodiment, the process of reacting a bisphenol A derivative, a phosphorus oxytrihalide, and a hydroxy compound includes:
a first step of reacting the bisphenol A derivative and the phosphorus oxytrihalide so as to produce a phosphorohalidate; and
a second step of reacting a reaction product obtained at the first step and a monophenol-based compound at the temperature of 120° C. or lower, and thereafter, increasing the temperature to 120° C. or higher, and reacting the phosphorohalidate and a hydroxy compound.
In one embodiment, the process of reacting a bisphenol A derivative, a phosphorus oxytrihalide, and a hydroxy compound includes:
a first step of reacting the bisphenol A derivative and the phosphorus oxytrihalide so as to produce a phosphorohalidate, and removing unreacted phosphorus oxytrihalide from a reaction product; and
a second step of reacting a reaction product obtained at the first step and a monophenol-based compound at the temperature of 120° C. or lower, and thereafter, increasing the temperature to 120° C. or higher, and reacting the phosphorohalidate and a hydroxy compound.
In one embodiment, the condensed phosphoric ester is 2,2-bis{4-[bis(phenoxy)phosphoryl]oxyphenyl}propane.
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the Invention
Hereinafter, the present invention will be specifically described, but the extent of the present invention is not limited to the following.
Examples of a process for preparing a condensed phosphoric ester of the present invention can generally be classified into the following three processes:
1. a process where a first step of reacting a bisphenol A derivative with a phosphorus oxytr
Fujisawa Taku
Nakamura Shin
Okawa Takafumi
Daihachi Chemical Industry Co. Ltd.
McKane Joseph K.
Shiao Robert
Snell & Wilmer LLP
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