Polyphenylene ether resin composition having excellent fire retardancy

A polyphenylene ether resin composition having excellent fire retardancy comprising PA0 (A) a polyphenylene ether resin, and PA0 (B) at least one phosphate compound selected from the group consisting of biphenyl phosphate compounds and naphthyl phosphate compounds.

This invention relates to a polyphenylene ether resin composition having 
excellent fire retardancy, and more specifically, to a polyphenylene ether 
resin composition containing a fire retardant whose volatilization is 
substantially prevented, and retaining excellent heat resistance and 
mechanical resistance. 
Polyphenylene ether is a resin having superior heat resistance, rigidity 
and electrical properties and is in widespread use as engineering 
plastics. However, the polyphenylene ether has inferior moldability and 
impact strength and moreover its fire retardancy is by no means 
satisfactory. 
In an attempt to improve the moldability or impact strength of 
polyphenylene ether polymers, techniques of blending them with 
styrene-type resins, elastomer-reinforced styrene-type resins or various 
elastomers have been disclosed in various publications including U.S. Pat. 
No. 3,383,435. It is well known however that the incorporation of 
styrene-type resins or elastomers greatly reduces the fire retardancy of 
polyphenylene ethers. 
Accordingly, it is known that to use a polyphenylene ether resin, or a 
resin composition comprising a polyphenylene ether, a styrene-type resin 
and/or an elastomer for applications requiring fire retardancy, it is 
essential to incorporate a fire retardant. Fire retardants which have 
heretofore been found to be effective are mainly phosphorus-containing 
compounds and halogen-containing compounds. For example, Japanese 
Laid-Open Patent Publications Nos. 32947/1974, 73248/1978, 16081/1980 and 
30737/1982 propose the use of aromatic phosphates of a monocyclic phenol 
compound. 
The aromatic phosphates, when blended with polyphenylene ethers as fire 
retardants, exhibit an excellent fire retarding effect and also improve 
the moldability of the polyphenylene ethers because of their plasticizing 
effect. On the other hand, these phosphate fire retardants inevitably 
reduce the heat resistance, shown, for example, by heat distortion 
temperature, and the mechanical strength properties, shown, for example, 
by tensile strength, of the polyphenylene ethers. Another problem, which 
is cumbersome, is that the phosphate fire retardant volatilizes from the 
surface of a molded article during molding to cause contamination of the 
mold and consequently impair the appearance of the molded article. This is 
attributed to the fact that the molding temperature for a molding material 
containing a polyphenylene ether resin is as high as 250.degree. to 
300.degree. C., and constitutes a serious problem in practical 
applications. For example, triphenyl phosphate or tricresyl phosphate, 
when kneaded with the resin component and heated to about 300.degree. C., 
will be volatilized even to an extent of about 20%. 
As a technique for solving the problem of the volatility of the phosphates, 
Japanese Laid-Open Patent Publication No. 118957/1980 proposes the use of 
an aromatic phophoric acid ester polymer. The use of this polymer provides 
a solution to the problem of volatility, but, on the other hand, does not 
improve the melt flowability of the polyphenylene ether and impairs its 
moldability, presumably because of the structure of the polymer. 
On the other hand, many known techniques exist with regard to 
halogen-containing compounds. For example, Japanese Laid-Open Patent 
Publication No. 7945/1973 proposes the incorporation of hexabromobenzene 
and antimony oxide. Japanese Patent Publication No. 39014/1973 and 
Japanese Laid-Open Patent Publication No. 57255/1977 disclose the addition 
of similar aromatic halogen compounds. The halogen-containing compounds 
hardly have a plasticizing effect on polyphenylene ethers, and when 
incorporated in the polyphenylene ethers, hardly reduce their heat 
resistance. This is the excellent characteristic not observed with the 
phosphate esters. But the halogen-containing compounds still have the 
defect of being unable to improve the moldability of the polyphenylene 
ethers. It is moreover well known that when the halogen-containing 
compounds are used as fire retardants, blooming occurs owing to the 
migration of the halogen-containing compounds to the surface of the molded 
article, and the thermal decomposition products of the halogen-containing 
compounds corrode the molding machine or molds. 
Japanese Patent Publication No. 38768/1973 discloses the use of a 
combination of a phosphate ester and an aromatic halogen compound. In this 
method, the essential defects caused by the use of the phosphate ester and 
the halogen-containing compound still remain. 
It is an object of this invention to provide a polyphenylene ether resin 
composition having excellent fire retardancy. 
Another object of this invention is to provide a polyphenylene ether resin 
composition containing a fire retardant whose volatilization is inhibited, 
and having good moldability, excellent heat resistance and excellent 
mechanical strength. 
Other objects of this invention along with its advantages will become 
apparent from the following description. 
According to this invention, these objects and advantages are achieved by a 
polyphenylene ether resin composition having excellent fire retardancy 
comprising 
(A) a polyphenylene ether resin, and 
(B) at least one phosphate compound selected from the group consisting of 
biphenylyl phosphate compounds represented by the following formula 
##STR1## 
wherein x is 0, 1 or 2, and R.sup.11 represents a linear or branched 
alkyl group having 1 to 8 carbon atoms or a phenyl group, provided that 
the biphenyl group and phenyl group may each be substituted by an alkyl 
group having 1 to 3 carbon atoms, and 
naphthyl phosphate compounds represented by the following formula 
##STR2## 
wherein y is 0, 1 or 2, and R.sup.22 represents a linear or branched alkyl 
group having 1 to 8 carbon atoms or a phenyl group, provided that the 
naphthyl group and phenyl group may each be substituted by an alkyl group 
having 1 to 3 carbon atoms. 
The polyphenylene ether resin (A) constituting the resin composition of 
this invention denotes a homo- or co-polymer of phenylene ether, and a 
grafted polyphenylene ether polymer obtained by grafting an aromatic vinyl 
compound to such a homo- or co-polymer. 
Preferably, the homopolymer or copolymer of polyphenylene ether is obtained 
by polycondensing a monocyclic phenol represented by the following formula 
##STR3## 
wherein R.sup.1 represents a lower alkyl group having 1 to 3 carbon atoms, 
and R.sup.2 and R.sup.3, independently from each other, represent a 
hydrogen atom or an alkyl group having 1 to 3 carbon atoms. 
The homopolymer can be obtained from a single monocyclic phenol, and the 
copolymer, from two or more monocyclic phenols. 
The alkyl group having 1 to 3 carbon atoms in general formula (I) denotes 
methyl, ethyl, n-propyl and iso-propyl groups. 
Examples of the monocyclic phenol of general formula (I) include 
2,6-dimethylphenol, 2,6-diethylphenol, 2,6-dipropylphenol, 
2-methyl-6-ethylphenol, 2-methyl-6-propylphenol, 2-ethyl-6-propylphenol, 
o-cresol, 2,3-dimethylphenol, 2,3-diethylphenol, 2,3-dipropylphenol, 
2-methyl-3-ethylphenol, 2-methyl-3-propylphenol, 2-ethyl-3-methylphenol, 
2-ethyl-3-propylphenol, 2-propyl-3-methylphenol, 2-propyl-3-ethylphenol, 
2,3,6-trimethylphenol, 2,3,6-triethylphenol, 2,3,6-tripropylphenol, 
2,6-dimethyl-3-ethylphenol and 2,6-dimethyl-3-propylphenol. Accordingly, 
examples of polyphenylene ether resins obtained by polycondensing these 
monocyclic phenols include homopolymers such as 
poly(2,6-dimethyl-1,4-phenylene)ether, 
poly(2,6-diethyl-1,4-phenylene)ether, 
poly(2,6-dipropyl-1,4-phenylene)ether, 
poly(2-methyl-6-ethyl-1,4-phenylene)ether, 
poly(2-methyl-6-propyl-1,4-phenylene)ether and 
poly(2-ethyl-6-propyl-1,4-phenylene)ether, and copolymers such as 
2,6-dimethylphenol/2,3,6-trimethylphenol copolymer, 
2,6-dimethylphenol/2,3,6-triethylphenol copolymer, 
2,6-diethylphenol/2,3,6-trimethylphenol copolymer and 
2,6-dipropylphenol/2,3,6-trimethylphenol copolymer. 
Of these, poly(2,6-dimethyl-1,4-phenylene)ether and 
2,6-dimethylphenol/2,3,6-trimethylphenol copolymer are preferred. 
Preferred as the aforesaid grafted polymer is a graft polymer obtained by 
grafting an aromatic vinyl compound represented by the following formula 
(II) 
##STR4## 
wherein R.sup.4 represents a hydrogen atom or a lower alkyl group, Z 
represents a halogen atom or a lower alkyl group, and p is 0 or an integer 
of 1 to 3, to the polyphenylene ether homo- or co-polymer. The grafted 
polymer can be produced, for example, by the method described in Japanese 
Laid-Open Patent Publication No. 126,800/1975. Examples of the aromatic 
vinyl compound are styrene, alpha-methylstyrene, vinyltoluene, 
vinylxylene, ethyl styrene, n-propylstyrene, iso-propylstyrene, 
chlorostyrene and bromostyrene. 
Especially preferred grafted polymers are a graft polymer obtained by 
grafting styrene to poly(2,6-dimethyl-1,4-phenylene)ether and a graft 
polymer obtained by grafting styrene to 
2,6-dimethylphenol/2,3,6-trimethylphenol copolymer. 
The composition of this invention may further contain a polystyrene resin 
(C) in addition to the polyphenylene ether resin (A). 
The polystyrene resin (C) is preferably one containing at least 25% by 
weight of structural units of the following formula (III) 
##STR5## 
wherein R.sup.4, Z and p are as defined with regard to formula (II). 
The lower alkyl group for R.sup.4 and Z in formula (III) is preferably an 
alkyl group having 1 to 3 carbon atoms, such as methyl, ethyl, n-propyl 
and iso-propyl. 
The halogen atom for Z in formula (III) is preferably chlorine or bromine. 
The structural units of formula (III) are derived from a styrene monomer of 
the above formula (II). 
Examples of preferred polystyrene resins are polystyrene, 
polychlorostyrene, rubber-modified polystyrene, poly(p-methylstyrene), 
rubber-modified poly(p-methylstyrene), styrene/butadiene copolymer, 
styrene/butadiene/acrylonitrile copolymer, styrene/acrylic acid 
rubber/acrylonitrile copolymer, styrene/alpha-methylstyrene copolymer, 
styrene/butadiene resinous block copolymer, styrene/maleic anhydride 
copolymer and rubber-modified styrene/maleic anhydride copolymer. 
Among these, high-impact polystyrene is especially preferred. The 
rubber-modified polystyrene may be obtained by modifying polystyrene with 
elastomers such as polybutadiene, butadiene-styrene copolymer rubber or 
EPDM. The rubber-modified polystyrene denotes a resin having an elastomer 
phase in the form of particles dispersed in a matrix of polystyrene. Such 
a resin can be formed by mechanically mixing polystyrene with an 
elastomer, or by copolymerizing an elastomer with a styrene-type monomer. 
Resins obtained by the latter method are preferably used in this 
invention. Industrially, the rubber-modified polystyrene resin is produced 
by graft polymerizing a styrene-type monomer in the presence of an 
elastomer. 
The polystyrene resin (C) may be one of the above-exemplified, resins, or a 
mixture of two or more of them. 
The phosphate compounds used in the resin composition of this invention are 
biphenylyl phosphates and naphthyl phosphates. 
The biphenylyl phosphates are represented by the following formula (B1) 
##STR6## 
wherein x is 0, 1 or 2, and R.sup.11 represents a linear or branched alkyl 
group having 1 to 8 carbon atoms or a phenyl group, provided that the 
biphenyl group and phenyl group may each be substituted by an alkyl group 
having 1 to 3 carbon atoms. 
In formula (B1), x is 0, 1 or 2. R.sup.11 represents a linear or branched 
alkyl group having 1 to 8 carbon atoms or a phenyl group. Examples of the 
alkyl group having 1 to 8 carbon atoms are methyl, ethyl, n-propyl, 
iso-propyl, n-butyl, iso-butyl, sec-butyl, t-butyl, n-pentyl, n-hexyl, 
n-heptyl and n-octyl. 
The biphenyl group and phenyl group present in formula (B1) may each be 
substituted by an alkyl group having 1 to 3 carbon atoms such as methyl, 
ethyl, n-propyl or iso-propyl. 
The biphenyl phosphate compounds of formula (B1) have at least one biphenyl 
structure, and according to the value of x, can be mono-, bis- or 
tris-biphenylyl phosphate compounds. 
Examples of the monobiphenylyl phosphate compound corresponding to general 
formula (B1) in which x is 2 include 
2- or 4-biphenylyl diphenylphosphate, 
2- or 4-biphenylyl dicresylphosphate, 
2- or 4-biphenylyl dixylenylphosphate, 
2- or 4-biphenylyl dinaphthylphosphate, 
2- or 4-biphenylyl dimethylphosphate, 
2- or 4-biphenylyl diethylphosphate, 
2- or 4-biphenylyl dipropylphosphate, 
2- or 4-biphenylyl dibutylphosphate, and 
2- or 4-biphenylyl dioctylphosphate. 
Examples of the bisbiphenylyl phosphate compound corresponding to general 
formula (B1) in which x is 1 include 
bis(2- or 4-biphenylyl) phenylphosphate, 
bis(2- or 4-biphenylyl) cresylphosphate, 
bis(2- or 4-biphenylyl) xylenylphosphate, 
bis(2- or 4-biphenylyl) naphthylphosphate, 
bis(2- or 4-biphenylyl) methylphosphate, 
bis(2- or 4-biphenylyl) ethylphosphate, 
bis(2- or 4-biphenyly) propylphosphate, 
bis(2- or 4-biphenylyl) butylphosphate, and 
bis(2- or 4-biphenylyl) octylphosphate. 
An example of the trisbiphenylyl phosphate compound corresponding to 
general formula (B1) in which x is 0 is tris(2- or 4-biphenylyl) 
phosphate. 
As stated hereinabove, one or both of the two benzene rings of the 
biphenylyl group in these biphenylyl phosphates may be substituted by an 
alkyl group having 1 to 3 carbon atoms. 
Among the aforesaid biphenylyl phosphate compounds, those of general 
formula (B1) in which x is 1 or 2, particularly 2, are preferred. Mono- or 
bis-biphenylyl phosphates of general formula (B1) in which R.sup.11 is a 
phenyl group or an alkyl-substituted phenyl group are more suitably used 
for achieving the objects of this invention. More preferably, these 
preferred compounds have a 4-biphenylyl groups as the biphenylyl phosphate 
group. 
The biphenylyl phosphate compounds are produced, for example, by reacting a 
phenylphenol compound or a mixture of it with an optional component such 
as a phenol compound or an aliphatic alcohol compound, with phosphorus 
oxychloride. The method of production is disclosed, for example, in U.S. 
Pat. Nos. 2,033,918 and 2,117,291. When the above mixture is used as a 
starting material, the proportion of the mono-, bis- or tris-biphenylyl 
phosphate compound can be varied by properly changing the mixing 
proportins or the sequence of reaction of the materials. When it is 
desired to obtain the mono- bis- or tris-biphenylyl phosphate compound 
singly, the desired biphenylyl phosphate compound may be isolated from the 
reaction product by a known separating procedure such as distillation. On 
the other hand, when two or more biphenylyl phosphate compounds of general 
formula (B1) are to be used in preparing the composition of this 
invention, the mixed product comprising the mono-, bis- and 
tris-biphenylyl phosphate compounds obtained by the reaction may be used 
as such. Where there is no need to adjust the mixing ratio of the mono-, 
bis- and tris-biphenylyl phosphate compounds strictly, the use of the 
mixed product as such is practical and advantageous. Generally, in the 
case of using a mixture of two or more biphenylyl phosphate compounds of 
general formula (B1) in the resin composition of this invention, the 
proportion of the monobiphenylyl phosphate compound used is desirably at 
least 50% by weight. Preferably, such a mixture is substantially free from 
the tris-biphenylyl phosphate. Especially preferably, the biphenylyl group 
in such phosphates is a 4-biphenylyl group. 
The naphthyl phosphate compounds used in this invention are represented by 
the following formula (B2) 
##STR7## 
wherein y is 0, 1 or 2, and R.sup.22 represents a linear or branched alkyl 
group having 1 to 8 carbon atoms or a phenyl group, provided that the 
naphthyl group and phenyl group may each be substituted by an alkyl group 
having 1 to 3 carbon atoms. 
In formula (B2), y is 0, 1 or 2. R.sup.22 is a linear or branched alkyl 
group having 1 to 8 carbon atoms, or a phenyl group. The naphthyl group or 
phenyl group present in formula (B2) may each be substituted by an alkyl 
group having 1 to 3 carbon atoms. Examples of the alkyl group may be the 
same as those given with regard to formula (B1). 
The naphthyl phosphate compounds of formula (B2) have at least one naphthyl 
group and can be mono-, bis- or tris-naphthyl phosphate compounds 
according to the value of y. 
Examples of the mononaphthyl phosphate compounds corresponding to general 
formula (B2) in which y is 2 include 
1- or 2-naphthyl diphenylphosphate, 
1- or 2-naphthyl dicresylphosphate, 
1- or 2-naphthyl dixylenylphosphate, 
1- or 2-naphthyl dimethylphosphate, 
1- or 2-naphthyl diethylphosphate, 
1- or 2-naphthyl dipropylphosphate, 
1- or 2-naphthyl dibutylphosphate, or 
1- or 2-naphthyl dioctylphosphate. 
Examples of the bisnaphthyl phosphate compounds corresponding to general 
formula (B2) in which y is 1 include 
bis(1- or 2-naphthyl)phenylphosphate, 
bis(1- or 2-naphthyl)cresylphosphate, 
bis(1- or 2-naphthyl)xylenylphosphate, 
bis(1- or 2-naphthyl)methylphosphate, 
bis(1- or 2-naphthyl)ethylphosphate, 
bis(1- or 2-naphthyl)propylphosphate, 
bis(1- or 2-naphthyl)butylphosphate, and 
bis(1- or 2-naphthyl)octylphosphate. 
Tris(1- or 2-naphthyl)phosphate is an example of the tris-naphthyl 
phosphate compounds according to general formula (B2) in which y is 0. 
As stated hereinabove, one or both of the two naphthyl rings in the 
naphthyl phosphate compounds may be substituted by an alkyl group having 1 
to 3 carbon atoms. 
Preferred naphthyl phosphate compounds are those of general formula (B2) in 
which y is 1 or 2, particularly 2. More preferred are mono- or 
bis-naphthyl compounds of formula (B2) in which R.sup.22 is a phenyl group 
or an alkyl-substituted phenyl group. 
The naphthyl phosphate compounds are produced usually by reacting a 
naphthol compound alone or a mixture of it with an optional component such 
as a phenol compound or an aliphatic alcohol component, with phosphorus 
oxychloride. The method of production is disclosed, for example, in U.S. 
Pat. No. 3,356,471 and West German Pat. No. 367,954. When the above 
mixture is used as a starting material, the proportion of the mono-, bis- 
or tris-naphthyl phosphate compound can be varied by properly changing the 
mixing proportions or the sequence of reaction of the materials. When it 
is desired to obtain the mono- bis- or tris-naphthyl phosphate compound 
singly, the desired naphthyl phosphate compound may be isolated from the 
reaction product by a known separating procedure such as distillation. On 
the other hand, when two or more naphthyl phosphate compounds of general 
formula (B2) are to be used in preparing the composition of this 
invention, the mixed product comprising the mono-, bis- and tris-naphthyl 
phosphate compounds obtained by the reaction may be used as such. Where 
there is no need to adjust the mixing ratio of the mono-, bis- and 
tris-naphthyl phosphate compounds strictly, the use of the mixed product 
as such is practical and advantageous. Generally, in the case of using a 
mixture of two or more naphthyl phosphate compounds of general formula 
(B2) in the resin composition of this invention, the proportion of the 
mononaphthyl phosphate compound used is desirably at least 50% by weight. 
Preferably, such a mixture is substantially free from the tris-naphthyl 
phosphate. 
In the present invention, the biphenylyl phosphate compound of formula (B1) 
is preferred to the naphthyl phosphate compound of formula (B2). When the 
two compounds are to be used in combination, it is desirable to use the 
biphenylyl phosphate compound in a proportion of at least 50% by weight. 
The resin composition of this invention may further comprise a triaryl or 
trialkyl phosphate compound represented by the following formula (IV) 
EQU O.dbd.P--OR.sup.5).sub.3 (IV) 
wherein R.sup.5 represents a linear or branched alkyl group having 1 to 8 
carbon atoms or a phenyl group, in which each phenyl group may be 
substituted by an alkyl group having 1 to 3 carbon atoms, in an amount 
which does not reduce the effect of this invention. 
A triaryl or trialkyl phosphate compound formed as a by-product in the 
reaction of a mixture of a phenyl phenol compound or a naphthol compound 
and a phenol compound or an aliphatic alcohol compound with phosphorus 
oxychloride may be used as a mixed product with a biphenylyl or naphthyl 
phosphate compound. If desired, a separately prepared triaryl or trialkyl 
phosphate compound may be added to the biphenylyl or naphthyl phosphate 
compound. 
In the resin composition of this invention, the proportion of the phosphate 
compound of formula (B1) and/or formula (B2) is preferably 1 to 50% by 
weight, more preferably 1 to 25% by weight, the remainder being the 
polyphenylene ether resin or a mixture of it with a polystyrene resin. 
When the polyphenylene ether resin and the polystyrene resin are used in 
combination, the polyphenylene ether is included in an amount of 
preferably 1 to 99% by weight, more preferably 10 to 90% by weight, 
especially preferably 20 to 80% by weight, based on total weight of the 
resin components. 
An elastomer component may also be incorporated in the resin composition of 
this invention in addition to the aforesaid resin components. The 
elastomer, as used herein, is an elastomer in an ordinary sense of the 
word. For example, the definition used at pages 71 to 78 of A. V. 
Tobolsky, "Properties and Structures of Polymers" (John Wiley & Sons, 
Inc., 1960) can be cited, and the elastomer means a polymer having a 
Young's modulus at ordinary temperature of 10.sup.5 to 10.sup.9 
dynes/cm.sup.2 (0.1 to 1020 kg/cm.sup.2). Specific examples of the 
elastomer include an A-B-A' type elastomeric block copolymer, a A-B'-A' 
type elastomeric block copolymer in which the double bond of the 
polybutadiene portion is hydrogenated, polybutadiene, polyisoprene, a 
copolymer of a diene compound and a vinyl aromatic compound, a radial 
tereblock copolymer, nitrile rubber, and ethylene/propylene copolymer, an 
ethylene/propylene/diene copolymer (EPDM), thiokol rubber, polysulfide 
rubber, acrylic rubber, polyurethane rubber, a grafted polymer of butyl 
rubber and polyethylene, a polyester elastomer and polyamide elastomer. 
Among these elastomers, the A-B-A' type elastomeric block copolymer and 
A-B'-A' type elastomeric block copolymer are preferred. The terminal 
blocks A and A' of these block copolymers are blocks of polymerized vinyl 
aromatic hydrocarbons, and B or B' is a block of a polymerized conjugated 
diene or a block of a conjugated diene in which most of the double bonds 
are hydrogenated. Desirably, the molecular weight of the block B is larger 
than the total molecular weight of the blocks A and A'. The terminal 
blocks A and A' may be identical or different. These blocks are a 
thermoplastic homopolymer or copolymer derived from a vinyl aromatic 
compound whose aromatic moiety is monocyclic or polycyclic. Examples of 
such a vinyl aromatic compound are styrene, alpha-methylstyrene, 
vinyltoluene, vinylxylene, ethylvinylxylene, vinylnaphthalene and mixtures 
of these. The central block B or B' is an elastomeric polymer derived from 
a conjugated diene-type hydrocarbon such as 1,3-butadiene, 
2,3-dimethylbutadiene, isoprene, 1,3-pentadiene or mixtures thereof. The 
terminal blocks A and A' have a molecular weight of preferably about 2,000 
to about 100,000, and the central block B has a molecular weight of 
preferably about 25,000 to about 1,000,000. When the resin composition of 
this invention further contains the elastomer in addition to the 
polyphenylene ether resin and the polystyrene resin, the proportion of the 
polyphenylene ether is usually at least 5% based on the total weight of 
the resin components in the composition although it varies depending upon 
the purpose for which the resin composition is produced. 
The resin composition of this invention may further include various 
additives or fillers in addition to the above resin components. Examples 
of the additives or fillers include stabilizers such as sterically 
hindered phenols, organic phosphites, phosphonites, phosphonous acids, 
cyclic phosphonites, hydrazine derivatives, amine derivatives, carbamate 
derivatives, thioethers, phosphoric triamide, benzimidazole derivatives 
and metal sulfides; ultraviolet absorbers such as benzotriazole 
derivatives, benzophenone derivatives, salicylate derivatives, sterically 
hindered amines, oxalic diamide derivatives and organic nickel complexes; 
polyolefin waxes as lubricants typified by polyethylene and polypropylene 
waxes; bromine-type fire retardants typified by decabromobiphenyl, 
decabromobiphenyl ether, pentabromotoluene, brominated bisphenol A, 
brominated polystyrene, a polycarbonate oligomer produced by using 
brominated bisphenol A, and a brominated polyphenylene ether oligomer; 
pigments typified by titanium dioxide, zinc oxide and carbon black; 
inorganic fillers typified by glass fibers, glass beads, asbestos, 
wollastonite, mica, talc, clay, calcium carbonate and silica; metal flakes 
typified by flakes of copper, nickel, aluminum and zinc; metal fibers 
typified by aluminum fibers, aluminum alloy fibers, brass fibers and 
stainless steel fibers; and organic fillers typified by carbon fibers and 
aromatic polyamide fibers. The amounts of these additional components vary 
depending upon the kinds of the substances used or the purposes for which 
they are added. 
The polyphenylene ether resin composition of this invention may be prepared 
by a conventional method. For example, the individual components are mixed 
by a blender such as a turnable mixer or a Henschel mixer and then kneaded 
by an extruder, a Banbury mixer, a roll, etc. 
The following examples illustrate the resin composition of this invention 
more specifically.

REFERENTIAL EXAMPLE 1 
Production of a biphenylyl phosphate mixture A: 
A reactor was charged with 340 g (2 moles) of p-phenylphenol and 307 g (2 
moles) of phosphorus oxychloride, and 3 g of anhydrous aluminum chloride 
was added. While a nitrogen gas was passed into the reactor, the mixture 
was heated to 150.degree. C. over 5 hours with stirring, and the mixture 
was further heated with stirring to 165.degree. C. over 3 hours. 
The reaction product was cooled, and dissolved in a nearly equal volume of 
carbon tetrachloride. The solution was shaken with a 3% by weight aqueous 
solution of sodium hydroxide three times and then with water to wash it. 
Carbon tetrachloride was evaporated by vacuum distillation from the 
solution after neutralization and purification to give a biphenylyl 
phosphate mixture (to be referred to as the "biphenylyl phosphate mixture 
A"). 
The composition of the biphenylyl phosphate mixture A was determined by 
GC-Mass analysis, and it was found to be a mixture of compounds of the 
formula 
##STR8## 
wherein the mixture is composed of 3% by weight of a compound of the above 
formula in which x is 0; 19% by weight of a compound of the above formula 
in which x is 1; 60% by weight of a compound of the above formula in which 
x is 2; and 19% by weight of a compound of the above formula in which x is 
3. 
EXAMPLE 1 
Fifty parts by weight of a 2,6-dimethylphenol/2,3,6-trimethylphenol 
copolymer (containing 5 mole % of 2,3,6-trimethylphenol) having an 
intrinsic viscosity, measured at 25.degree. C. in chloroform as a solvent, 
of 0.51 dl/g; 46 parts by weight of rubber-modified polystyrene containing 
a polystyrene matrix with an intrinsic viscosity, measured at 25.degree. 
C. in chloroform as a solvent, of 0.89 dl/g and having a gel content of 
16.5% by weight; 3 parts by weight of a 
polystyrene/polybutadiene/polystyrene-type elastomeric block copolymer 
(the weight ratio of styrene/butadiene=30/70, viscosity of 1500 cps as 
measured by a Brookfield Model RTV viscometer for a 20% toluene solution 
at 25.degree. C.); 1 part by weight of an ethylene/propylene copolymer 
(having a reduced specific viscosity, measured at 135.degree. C. using 
decalin as a solvent in a concentration of 0.1 g/100 ml, of 2.0); 19 parts 
by weight of the biphenylyl phosphate mixture A; 0.3 part by weight of 
tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite; 0.6 
parts by weight of 2,2'-methylene-bis(4-methyl-6-tert-butylphenol); and 5 
parts by weight of titanium oxide were mixed thoroughly by a Henschel 
mixer. The mixture was kneaded by a twin-screw extruder to form pellets. 
The pellets were molded into a test piece having a thickness of 1.5 mm, a 
width of 12.7 mm and a length of 127 mm by an injection molding machine. 
The test piece was subjected to a burning test in accordance with UL-94 
standards, and the average burning time was measured. Similarly, a test 
piece having a thickness of about 6 mm was produced by injection molding, 
and its heat distortion temperature was measured. Furthermore, a 
dumbbell-shaped test piece having a thickness of about 3 mm was produced 
by injection molding, and its tensile strength was measured. 
The melt flow value of the composition was measured at 230.degree. C. under 
a load of 60 kg by using a "Koka-type" flow tester. The weight loss (%) of 
the composition on heating was measured by TGA at 300.degree. C. by 
heating at a rate of 10.degree. C./min. 
The results are shown in Table 1. 
REFERENTIAL EXAMPLE 2 
Production of a biphenylyl phosphate mixture B: 
Referential Example 1 was repeated except that o-phenylphenol was used 
instead of p-phenylphenol. There was obtained a biphenylyl phosphate 
mixture (B). 
The biphenylyl phosphate mixture B was analyzed by the same method as in 
Referential Example 1 and found to be composed of 2% by weight of a 
compound of the following formula in which x is 0; 18% by weight of a 
compound of the following formula in which x is 1; 62% by weight of a 
compound of the following formula in which x is 2; and 18% by weight of a 
compound of the following formula in which x is 3. 
##STR9## 
EXAMPLE 2 
Test pieces were prepared by repeating Example 1 except that the biphenylyl 
phosphate mixture B obtained in Referential Example 2 was used instead of 
the biphenylyl phosphate mixture A. 
The various properties of the test pieces were measured as in Example 1, 
and the results are shown in Table 1. 
REFERENTIAL EXAMPLE 3 
The biphenylyl phosphate mixture A obtained in Referential Example 1 was 
vacuum distilled to obtain a distillate having a boiling point of 
245.degree. to 250.degree. C. under a reduced pressure of 0.3 mmHg. This 
distillate was found to be 4-biphenylyl diphenylphosphate. 
EXAMPLE 3 
Test pieces were prepared by repeating Example 1 except that 4-biphenylyl 
diphenylphosphate obtained in Referential Example 3 was used instead of 
the biphenylyl phosphate mixture A. 
The properties of the test pieces were measured as in Example 1, and the 
results are shown in Table 1. 
COMATIVE EXAMPLES 1-3 
Example 1 was repeated except that triphenyl phosphate (Comparative Example 
1), tricresyl phosphate (Comparative Example 2), and trixylenyl phosphate 
(Comparative Example 3) were used instead of the biphenylyl phosphate 
mixture A. 
The results are shown in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Example (Ex.) or Average 
Weight loss 
Heat distortion 
Tensile 
Melt flow 
Comparative burning time 
upon heating 
temperature 
strength 
value 
Example (CEx.) 
Phosphate (seconds) 
(wt. %) 
(.degree.C.) 
(kg/cm.sup.2) 
(cc/sec) 
__________________________________________________________________________ 
Ex. 1 biphenylyl phosphate 
5.9 0.6 85 450 0.9 .times. 10.sup.-1 
mixture A 
Ex. 2 biphenylyl phosphate 
6.0 1.2 84 445 1.0 .times. 10.sup.-1 
mixture B 
Ex. 3 4-biphenylyl 
6.0 0.3 87 450 1.3 .times. 10.sup.-1 
diphenylphosphate 
CEx. 1 triphenyl phosphate 
4.2 3.2 78 360 1 .times. 10.sup.-1 
CEx. 2 tricresyl phosphate 
5.6 2.6 76 340 1.1 .times. 10.sup.-1 
CEx. 3 trixylenyl phosphate 
6.1 2.0 75 360 1.2 .times. 10.sup.-1 
__________________________________________________________________________ 
REFERENTIAL EXAMPLE 4 
Production of a biphenylyl phosphate mixture C: 
A reactor was charged with 376 g (4 moles) of phenol, 307 g (2 moles) of 
phosphorus oxychloride and 3 g of anhydrous aluminum chloride, and the 
reaction was carried out by the same operation as in Referential Example 
1. The unreacted phosphorus oxychloride was evaporated from the reaction 
mixture. The residue was cooled to room temperature, and 304 g (2 moles) 
of p-phenylphenol was added. The reaction was completed by the same 
operation as in Referential Example 1. 
The reaction product was neutralized and purified by the same operation as 
in Referential Example 1 to give a biphenylyl phosphate mixture (to be 
referred to as the "biphenylyl phosphate mixture C). 
The composition of the biphenylyl phosphate mixture C was analyzed by the 
same method as in Referential Example 1, and it was found to be composed 
of 0% by weight of a compound of the following formula in which x is 0; 
16by weight of a compound of the following formula in which x is 1; 64% by 
weight of a compound of the following formula in which x is 2; and 20% by 
weight of a compound of the following formula in which x is 3. 
##STR10## 
EXAMPLE 4 
Forty parts by weight of the same 2,6-dimethylphenol/2,3,6-trimethylphenol 
copolymer as used in Example 1; 57 parts by weight of the same 
rubber-modified polystyrene as used in Example 1; 2 parts by weight of the 
same elastomeric block copolymer as used in Example 1; 1 part of the same 
ethylene/propylene copolymer as used in Example 1; 0.34 part by weight of 
tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite; 0.57 
part by weight of 2,2'-methylene-bis(4-methyl-6-tert-butylpenol); 7 parts 
by weight of titanium oxide; and 9 parts by weight of the biphenylyl 
phosphate mixture C obtained in Referential Example 4 were thoroughly 
mixed by a Henschel mixer. The mixture was molded into test pieces as in 
Example 1. 
The properties of the test pieces were measured as in Example 1, and the 
results are shown in Table 2. 
COMATIVE EXAMPLES 4-5 
Example 4 was repeated except that triphenyl phosphate (Comparative Example 
4) or tricresyl phosphate (Comparative Example 5) was used instead of the 
biphenylyl phosphate mixture C. The results are shown in Table 2. 
COMATIVE EXAMPLE 6 
Example 4 was repeated except that the biphenylyl phosphate mixture C was 
not used. The resultts are shown in Table 2. 
TABLE 2 
__________________________________________________________________________ 
Example (Ex.) or Average 
Weight loss 
Heat distortion 
Tensile 
Comparative burning time 
upon heating 
temperature 
strength 
Example (CEx.) 
Phosphate (seconds) 
(wt. %) 
(.degree.C.) 
(kg/cm.sup.2) 
__________________________________________________________________________ 
Ex. 4 biphenylyl phosphate 
18.5 0.3 107 540 
mixture C 
CEx. 4 triphenyl phosphate 
12.2 1.8 97 500 
CEx. 5 tricresyl phosphate 
17.3 1.6 95 480 
CEx. 6 None above 30 
0.1 123 -- 
__________________________________________________________________________ 
REFERENTIAL EXAMPLE 5 
Production of a biphenylyl phosphate mixture D: 
Referential Example 1 was repeated except that 432 g (4 moles) of mixed 
cresols were used instead of 376 g of phenol. There was obtained a 
biphenylyl phosphate mixture (to be referred to as the "biphenylyl 
phosphate mixture D"). 
The composition of the biphenylyl phosphate mixture D was analyzed by the 
same method as in Referential Example 1, and it was found to be composed 
of 3% by weight of a compound of the following formula in which x is 0; 
15% by weight of a compound of the following formula in which x is 1; 62% 
by weight of a compound of the following formula in which x is 2; and 20% 
by weight of a compound of the following formula in which x is 3. 
##STR11## 
EXAMPLE 5 
One hundred parts by weight of poly(2,6-dimethyl-1,4-phenylene)ether having 
an intrinsic viscosity, measured at 25.degree. C. in chloroform, of 0.52 
dl/g; 0.3 part by wight of 
tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylenediphosphonite; 0.6 part 
by weight of 2,2'-methylene-bis(4-methyl-6-tert-butylphenol); and 10 parts 
by weight of the biphenylyl phosphate mixture D obtained in Referential 
Example 5 were thoroughly mixed by a Henschel mixer. The mixture was then 
molded into test pieces. 
The properties of the test pieces were measured in the same way as in 
Example 1, and the results are shown in Table 3. 
REFERENTIAL EXAMPLE 6 
Production of tris(4-biphenylyl) phosphate: 
A reactor was charged with 510 g (3 moles) of p-phenylphenol, 153 g (1 
mole) of phosphorus oxychloride, and 1.5 g of anhydrous aluminum chloride, 
and with stirring, the mixture was heated to 150.degree. C. over 5 hours 
and further to 200.degree. C. over 8 hours while passing a nitrogen gas. 
The reaction was further carried out for 5 hours at 240.degree. C. to 
complete the reaction. 
The reaction product was dissolved in benzene. The insoluble materials were 
separated by filtration. The filtrate was fully shaken with a 3% by weight 
aqueous solution of sodium hydroxide to wash it, and then further with 
water. Benzene was evaporated under reduced pressure from the solution 
which had been subjected to neutralization and purification. 
The resulting crude crystalline compound was recrystallized from a mixture 
of benzene and petroleum ether to give tris(4-biphenylyl)phosphate as 
crystals having a melting point of 137.degree. C. 
EXAMPLE 6 
Example 5 was repeated except that the tris(4-biphenylyl)phosphate obtained 
in Referential Example 6 was used instead of the biphenylyl phosphae 
mixture D. 
The results are shown in Table 3. 
COMATIVE EXAMPLE 7 
Example 5 was repeated except that triphenyl phosphate was used instead of 
the biphenylyl phosphate mixture D. The results are shown in Table 3. 
TABLE 3 
______________________________________ 
Average 
burning Weight loss 
time upon heating 
Phosphate (seconds) 
(wt. %) 
______________________________________ 
Example biphenylyl 6.4 0.2 
5 phosphate 
mixture D 
Example tris(4-bi- 9.7 0 
6 phenylyl) 
phosphate 
Compar- triphenyl 5.2 1.6 
ative phosphate 
Example 
______________________________________ 
REFERENTIAL EXAMPLE 7 
Production of a naphthyl phosphate mixture A: 
A reactor was charged with 289 g (2 moles) of 2-naphthol and 307 g (2 
moles) of phosphorus oxychloride, and 3 g of anhydrous aluminum chloride 
was added. With stirring, the mixture was heated to 150.degree. C. over 5 
hours and then to 165.degree. C. over 3 hours, while a nitrogen gas was 
passed. The reaction product was cooled to room temperature, and 376 g (4 
moles) of phenol was added. The mixture was stirred while the temperature 
was gradually elevated. While passing a nitrogen gas, the mixture was 
heated to 190.degree. C. over 6 hours and then to 200.degree. C. over 3 
hours to complete the reaction. 
The reaction product was cooled, and dissolved in a nearly equal volume of 
carbon tetrachloride. The resulting solution was shaken three times with a 
3% by weight of aqueous solution of sodium chloride, and then with water 
to wash it. Carbon tetrachloride was evaporated by vacuum distillation 
from the solution which had thus been subjected to neutralization and 
purification. Then, about 70 g of a distillate having a boiling point of 
175.degree. to 180.degree. C. under a reduced pressure of 5 mmHg was 
evaporated to give a naphthyl phosphate mixture (to be referred to as the 
"naphthyl phosphate mixture A"). 
The composition of the resulting naphthyl phosphate mixture A was 
determined by GC-MASS analysis. It was found to be composed of 2% by 
weight of a compound of the following formula in which x is 0; 27% by 
weight of a compound of the following formula in which x is 1; 64% by 
weight of a compound of the following formula in which x is 2; and 7% by 
weight of a compound of the following formula in which x is 3. 
##STR12## 
EXAMPLE 7 
Test pieces were prepared in the same way as in Example 1 except that the 
naphthyl phosphate mixture A obtained in Referential Example 7 was used 
instead of the biphenylyl phosphate mixture. The properties of the test 
pieces were measured as in Example 1, and the results are shown in Table 
4. 
REFERENTIAL EXAMPLE 8 
Production of a naphthyl phosphate mixture B: 
Referential Example 7 was repeated except that 1-naphthol was used instead 
of 2-naphthol. There was obtained a naphthyl phosphate mixture (to be 
referred to as the "naphthyl phosphate mixture B"). 
The composition of the naphthyl phosphate mixture B was analysed by the 
same method as in Referential Example 7, and it was found to be composed 
of 1% by weight of a compound of the following formula in which x is 0; 
28% by weight of a compound of the following formula in which x is 1; 65% 
by weight of a compound of the following formula in which x is 2; and 6% 
by weight of a compound of the following formula in which x is 3. 
##STR13## 
EXAMPLE 8 
Test pieces were prepared in the same way as in Example 7 except that the 
naphthyl phosphate mixture B obtained in Referential Example 8 was used 
instead of the naphthyl phosphate mixture A. The properties of the test 
pieces were measured as in Example 7, and the results are shown in Table 
4. 
REFERENTIAL EXAMPLE 9 
The naphthyl phosphate mixture A obtained in Referential Example 7 was 
distilled under vacuum, and a distillate having a boiling point of 
310.degree. to 320.degree. C. under a reduced pressure of 0.4 mmHg was 
separated. This distillate was 2-naphthyl diphenylphosphate 
EXAMPLE 9 
Test pieces were obtained in the same way as in Example 7 except that 
2-naphthyl diphenyl phosphate obtained in Referential Example 9 was used 
instead of the naphthyl phosphate mixture A. 
The properties of the test pieces were measured in the same way as in 
Example 7, and the results are shown in Table 4. For easy comparison, 
Table 4 also gives the results obtained in Comparative Examples 1, 2 and 
3. 
TABLE 4 
__________________________________________________________________________ 
Example (Ex.) or Average 
Weight loss 
Heat distortion 
Tensile 
Melt flow 
Comparative burning time 
upon heating 
temperature 
strength 
value 
Example (CEx.) 
Phosphate (seconds) 
(wt. %) 
(.degree.C.) 
(kg/cm.sup.2) 
(cc/sec) 
__________________________________________________________________________ 
Ex. 7 naphthyl phosphate 
5.6 0.8 85 446 1.1 .times. 10.sup.-1 
mixture A 
Ex. 8 naphthyl phosphate 
5.8 0.8 86 445 1.2 .times. 10.sup.-1 
mixture B 
Ex. 9 2-naphthyl 
6.1 0.5 87 450 1.0 .times. 10.sup.-1 
diphenylphosphate 
CEx. 1 triphenyl phosphate 
4.2 3.2 78 360 1.0 .times. 10.sup.-1 
CEx. 2 tricresyl phosphate 
5.6 2.6 76 340 1.1 .times. 10.sup.-1 
CEx. 3 trixylenyl phosphate 
6.1 2.0 75 360 1.2 .times. 10.sup.-1 
__________________________________________________________________________ 
REFERENTIAL EXAMPLE 10 
Production of a naphthyl phosphate mixture C: 
A reactor was charged with 376 g (4 moles) of phenol, 307 g (2 moles) of 
phosphorus oxychloride and 3 g of anhydrous aluminum chloride, and the 
reaction was carried out by the same operation as in Referential Example 
7. The unreacted phosphorus oxychloride was evaporated from the reaction 
mixture, and the residue was cooled to room temperature. Then, 340 g (2 
moles) of 2-naphthol as added, and the reaction was completed by the same 
operation as in Referential Example 7. 
The resulting reaction product was neutralized and purified by the same 
operation as in Referential Example 7. Carbon tetrachloride was evaporated 
from the reaction mixture by distillation under reduced pressure to give a 
naphthyl phosphate mixture (to be referred to as the "naphthyl phosphate 
mixture C"). 
The composition of the naphthyl phosphate mixture C was analyzed by the 
same method as in Referential Example 7, and it was found to be composed 
of 0% by wight of a compound of the following formula in which x is 0; 21% 
by weight of a compound of the following formula in which x is 1; 56% by 
weight of a compound of the following formula in which x is 2; and 23% by 
weight of a compound of the following formula in which x is 3. 
##STR14## 
EXAMPLE 10 
Example 4 was repeated except that the naphthyl phosphate mixture C 
obtained in Referential Example 10 was used instead of the biphenylyl 
phosphate mixture C. The results are shown in Table 5. For easy 
comparison, Table 5 also gives the results obtained in Comparative 
Examples 4, 5 and 6. 
TABLE 5 
__________________________________________________________________________ 
Example (Ex.) or Average 
Weight loss 
Heat distortion 
Tensile 
Comparative burning time 
upon heating 
temperature 
strength 
Example (CEx.) 
Phosphate (seconds) 
(wt. %) 
(.degree.C.) 
(kg/cm.sup.2) 
__________________________________________________________________________ 
Ex. 10 naphthyl phosphate 
16.3 0.4 105 530 
mixture C 
CEx. 4 triphenyl phosphate 
12.2 1.8 97 500 
CEx. 5 tricresyl phosphate 
17.3 1.6 95 480 
CEx. 6 None above 30 
0.1 123 -- 
__________________________________________________________________________ 
REFERENTIAL EXAMPLE 11 
Production of a naphthyl phosphate mixture D: 
Referential Example 7 was repeated except that 432 g (4 moles) of mixed 
cresols were used instead of 376 g of phenol. There was obtained a 
naphthyl phosphate mixture (to be referred to as the "naphthyl phosphate 
mixture D"). 
The composition of the naphthyl phosphate mixture D was analyzed by the 
same method as in Referential Example 7, and it was found to be composed 
of 2% by weight of a compound of the following formula in which x is 0; 
25% by weight of a compound of the following formula in which x is 1; 67% 
by wight of a compound of the following formula in which x is 2; and 6% by 
weight of a compound of the following formula in which x is 3. 
##STR15## 
EXAMPLE 11 
Example 5 was repeated except that the naphthyl phosphate mixture D 
obtained in Referential Example 11 was used instead of the biphenylyl 
phosphate mixture D. The results are shown in Table 6. 
REFERENTIAL EXAMPLE 12 
Production of tris(2-naphthyl)phosphate: 
A reactor was charged with 434 g (3 moles) of 2-naphthol, 153 g (1 mole) of 
phosphorus oxychloride and 1.5 g of anhydrous aluminum chloride. With 
stirring, the mixture was heated to 150.degree. C. over 5 hours, and then 
to 200.degree. C. over 8 hours, while passing nitrogen gas. Finally, the 
reaction mixture was heated at 240.degree. C. for 5 hours to complete the 
reaction. 
The reaction product was dissolved in benzene, and the insoluble materials 
were separated by filtration. The filtrate was fully shaken with a 3% by 
weight aqueous solution of sodium hydroxide and then with water to wash 
it. Benzene was evaporated under reduced pressure from the solution which 
had been subjected to neutralization and purification. 
The resulting crude cyrstalline product was recrystallized from a mixture 
of benzene and petroleum ether to give tris(2-naphthyl) phosphate as 
crystals having a melting point of 110.degree. to 111.degree. C. 
EXAMPLE 12 
Example 11 was repeated except that the tris(2-naphthyl) phosphate obtained 
in Referential Example 12 was used instead of the naphthyl phosphate 
mixture D. 
The results are shown in Table 6. For comparison, Table 6 also gives the 
results of Comparative Example 7. 
TABLE 6 
______________________________________ 
Average 
burning Weight loss 
time upon heating 
Phosphate (seconds) 
(wt. %) 
______________________________________ 
Example naphthyl 6.1 0.3 
11 phosphate 
mixture D 
Example tris(2- 8.6 0.1 
12 naphthyl) 
phosphate 
Compar- triphenyl 5.2 1.6 
ative phosphate 
Example 
______________________________________ 
As is seen from the foregoing Examples and Comparative Examples, the 
phosphate compounds specified in this invention impart an effective fire 
retarding effect to polyphenylene ether resins without degrading their 
heat resistance, mechanical strength and moldability. It is particularly 
noteworthy that weight loss of the phosphate compounds of this invention 
upon heating is much lower than that of known phosphate compounds typified 
by triphenyl phosphate. This means that the phosphate compounds used in 
this invention do not volatilize from the polyphenylene ether resin 
composition even at high temperatures. This is a very useful phenomenon in 
practical applications.