Note: Descriptions are shown in the official language in which they were submitted.
f,~
PHOSPHORUS COMPOUNDS
Organic phosphorus compounds, such as phosphates, are well known
for use as flame retarding agents in organic plastics, either as the sole
such agents or in combination with other ingredients such as halogen com-
pounds. In such uses the phosphorus compound often also acts as a plasti-
cizer.
One aspect of this invention relates to a peroxygen composition
which comprises a phosphate ester with at least one ester coupling to a sub-
stituted aromatic ring, said aromatic ring having at least one substituent
comprising an aliphatic carbon directly attached to the ring and with an
ether peroxide group attached to said aliphatic carbon.
Another aspect is a process for preparing a peroxygen composi-
tion by contacting oxygen gas, an acid acceptor and a compound comprised
of a phosphate ester with at least one ester coupling to a substituted
aromatic ring, said aromatic ring having at least one substituent compris-
ing an aliphatic carbon with at least one abstractable hydrogen directly
attached thereto, and continuing sald process until said composition
contains at least 1 peroxygen group per 100 phosphorus atoms.
In the said peroxygen comFosition the peroxy group -00- is
directly bonded on the one hand to an aliphatic carbon directly attached
to an aromatic ring and on the other hand to (a) a hydrogen atom or (b~
aliphatic carbon. In (a) the campound is a hydroperoxide (HOOC-); in (b)
it is a peroxyether (-C-00-¢-). Ei-ther or both t~pes of groups may be
present. Preferably the peroxy group (-00-) is on a tertiary carbon atom
(e.g. in a peroxyisopropylphenyl group of the formula fH3
-oo-c~)
The pnosphorus-containing peroxy compounds of this invention
have a flame retarding effect on plastics into which they are incorporated,
owing in large part to their phosphorus content. They also have addition-
al effects. For instance, they may increase the flame resistance (as com-
pared to identical phosphorus compounds without the peroxy groups); see,
for example, the data tabulated in Example 1 below. They may improve the
flame resistance of plastics while reducing the often-undesirable decrease
in glass -transition temperature (Tg) that often results from incorporation
of flame retardants; see, for example,
".. . .. ..
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- 2 -
the data tabulated in Example 5, below. Their use may
increase the compatibility of the organic plastic with
the organic phosphorus compound; see, for instance, the
improvement in blooming characteristics noted in Example
7 below. They may act synergistically with flame re-
tarding halogen compounds; see, for instance, the data
in Example 8, below.
The phosphorus-containing peroxy compounds of this
invention may also be used in place of other peroxy com-
pounds such as those conventionally employed in the artas curing (cross-linking; vulcanizing~ agents, polymeri-
zation catalysts or initiators for other free radical re-
actions such as grafting or synergism with halogen-con-
taining flame retardants. In conventional processes of
this type, the peroxy compound (such as dicumyl peroxide)
forms low molecular weight decomposition products which
are volatile, subject to migration and easily extracted.
The resultant odor is objectionable and has been a major
drawback in their use. In contrast decomposition of the
peroxy compounds of this invention yields phosphorus-
containing residues which are generally of relatively
high molecular weight, less extractable, less volatile
and less odorous. Furthermore, these phosphorus-con-
taining residues are less likely to be flammable than the
residues (such as hydrocarbons) from conventional per-
oxides. As noted above, their use may incorporate a
phosphorus-containing residue directly into the chemical
structure of the polymer.
In one preferred aspect of the invention, the phos-
phorus-containing peroxy compounds are formed, and used,
in admixture with unperoxidized flame-retarding phos-
phorus compounds. Conveniently, a mixture of peroxidized
and unperoxidized phosphorus compounds is formed by par-
tially peroxidizing the phosphorus compound. Such a mix-
ture may also contain molecules of varying peroxide con-
tents, that is, a mixture of molecules, some having one
peroxy group per molecule and others having two or even
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:
-- 3 --
three or more peroxy groups per molecule. Also there may
be both hydroperoxy and peroxy ether groups in the mix-
ture. One may carry out the peroxidation process to ob-
tain a relatively high conversion to peroxy compounds
(and concomitant formation of molecules having a plural-
ity of peroxy groups) and then blend the resulting per-
oxy rich mixture with more of the phosphorus-containing
starting material or with another phosphorus-containing
flame retardant compound. One may carry out the peroxi-
10 dation process on a mixture of phosphorus compounds, one
(or more) of which is resistant to peroxidation and one
(or more) of which is more readily peroxidized. The per-
oxidation process may also be carried out in the presence
of other compounds such as solvents or diluents (see Ex.
15 9 _ below) or polymerizable monomeric or polymeric ma-
terials such as styrene, which may contain dispersed or
dissolved polymeric materials such as unsaturated poly-
ester resin (a relatively low polymer which copolymerizes
with the styrene) or higher polymers such as diolefin
20 polymers (for example, rubbery polybutadiene-1,3, buta-
diene copolymers, and the like). In the peroxy-con-
taining mixture, there is preferably at least one peroxy-
alkylaryl group per 500 phosphorus atoms, more preferably
at least one such group per 100 P atoms (for example,
25 about 3, 5, 10, 20, 100, 200 or even 300 such groups per
100 P atoms) and the carbon:phosphorus atomic ratio i5
preferably less than about 100:1, a C:P ratio well below
50:1 (such as about 30:1 or less) being more preferred
in order to provide a desirable level of phosphorus con-
30 tent for flame retardancy.
The following Examples are given to illustrate this
invention further. In this application all proportions
are by weight and all temperatures are ~C unless other-
wise indicated.
EXAMPLE 1
130 parts of a blend of styrene and ethylenically
unsaturated polyester resins which are soluble in styrene
: ~ . . .
. :
.iL'Z~ DSC~ -
-- 4 --
and copolymerizable therewith i5 mixed with the following
additives in the indicated amounts and then heat-cured in
sealed glass tubes of 6 mm diameter (at the temperatures
indicated below) overnight (16 hours) after which the
5 cured material is removed from its tube and its oxygen
index is determined; in some cases, as indicated, the
cured material, after removal from its tube, is given a
post-cure in air at 100 C overnight. Oxygen index is a
measure of flame resistance (ASTM D2863).
The styrene-polyester resin solution is made by
mixing 50 parts styrene, 50 parts "Dion 6421" (a poly-
ester of [a slight excess of3 propylene glycol and a 1:1
[molar] mi~ture of maleic and isophthalic acid manufac-
tured by Diamond Shamrock Corporation and 30 parts "Dow
15 FR-1540n -(a blend of 30% styrene and 70% of a polyester
derived from ~aleic anhydride and dibromoneopentyl gly-
- col manufactured by Dow Chemical Company).
- The results are as follows:
Oxygen
20 Additive and curing conditions Index
(a) 3 parts benzoyl peroxide; cured at 70 C. 23
(b) 3 parts benzoyl peroxide plus 20 parts
4-isopropylphenyl diphenyl phosphate;
cured at 70 C. 25.7
25 (c) 20 parts of product made by treating 4-
isopropylphenyl diphenyl phosphate with
oxygen to form peroxyalkyl compound (as
in Example 3 below~; cured at 70 C. 28~0
. (d) 3 parts benzoyl peroxide plus 20 parts
of phosphate ester of partially isopro-
pylated phenol, made in the general manner
described in Example 4a below; cured at
70 C and then post-cured in air at 100~C. 28.8
. (e) 20 parts of product made by treating the
phosphate named in d above with oxygen
to form peroxyalkyl compound (as in Ex-
ample 2a below); cured at 70 C and post-
* Trade Mark
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Oxygen
Additive and curi_~ conditions Index
cured in air at 100 C. 29.9
(f) 10 parts of oxygen-treated material
of Example 2a below
~i) cured at 70 C 29.6
(ii) cured at 110-C 33.5
tg) 3 parts benzoyl peroxide plus 30 parts
tris (3-ethylphenyl) phosphate 27.4
(h) 30 parts of product made by treating tris
(3-ethylphenyl) phosphate with oxygen to
form peroxyalkyl compound (as in Example
2b below) 31.3
These results indicate that the addition of the triaryl
phosphates improves the flame resistance and that treat-
15 ing the phosphate ester to form peroxyalkylaryl phos-
phates prior to mixing with the polymerizable mixture
gives an additional significant improvement.
In each of Examples la, 1b, 1d and 1g there is also
present an amount of tricresyl phosphate equal to the
20 amount of benzoyl peroxide, since the latter is, in each
case, added in the form of 50:50 mixture ~ith tricresyl
phosphate, sold as "Luperco ATC paste~ by Lveidol Divi-
sion of Pennwalt Corporation.
EXAMPLE 2
(a) The additive used in Example 1e and f is pre-
pared by passing oxygen through 20g of the phosphate
ester having dispersed therein 0.2g of sodium formate
and 10 mg of manganese naphthenate at about 125-C. The
oxygenis bubbled through the material for about 8 1/2
30 hours giving a product which, according to hydropero~ide
titration (described below~ contains about 28 hydroper-
oxyalkyl groups per 100 phosphorus atoms.
(b) The product used in Example 1h is made in a
similar manner, in the presence of 1% sodium formate and
35 0.05% manganese naphthenate the oxygen being bubbled
through for about 23 hours; the hydroperoxide titration
,* Trade i~ark
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:
indicates that there are about 20 hydroperoxyalkyl groups
per 100 phosphorus atoms.
In view of these analyses for hydroperoxyalkyl con-
tent, it is quite probable, statistically, that the pro-
S ducts of Example 2a and _ contain triaryl phosphate mole-
cules having two (or three) hydroperoxyalkyl groups per
molecule together with triaryl phosphate molecules having
only one hydroperoxyalkyl group and unchanged triaryl
phosphate molecules.
EXAMPLE 3
The additive used in Example lc is prepared by pas-
sing oxygen through lOg of 4-isopropylphenyl diphenyl
phosphate having dispersed therein O.lg of sodium formate
and 10 mg manganese naphthenate at 125C. The oxygen is
bubbled through the material for about 57 hours giving a
product which, according to hydroperoxide titration des-
cribed below, contains about 60 hydroperoxyalkyl groups
per 100 phosphorus atoms.
EX~PLE 4
(a) Phenol is alkylated with propylene, in the man-
ner described in U.S. patent 3,576,923, dated April 27,
1971, to produce a mixture having about 0.33 isopropyl
groups per phenol (about 15 parts of propylene reacted,
per 100 parts of phenol) and in which the ratio of o-
isopropyl groups to m- and p-isopropyl groups is in the
neighborhood of about 2:1~ This mixture is then iso-
merized, in the manner described in U.S. patent 3,859,395
to change the o:m,p ratio (from its initial value of
about 2:1) to about 1:2. The resulting isomerized alkyl-
ate is then esterified with POC13 (in the general manner
described in U.S. Patent 3,576,923) to produce a triaryl-
phosphate which is purified by distillation at subatmo-
spheric pressure. The presence of 0.33 isopropyl groups
per phenol (in the alkylate) indicates that in the tri-
aryl phospate there are about 100 isopropyl groups per
100 phosphorus atoms.
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-- 7
(b) To the triarylphosphate of 4a there are added
0.5~ sodium formate and 0.05% manganese naphthenate, and
oxygen at substantially atmospheric pressure is then
bubbled (from a capillary tube) through the phosphate
5 maintained at about 125 C for about 16 hours. As in the
other Examples herein, the mixture is treated, by fil-
tering or decanting after settling, to remove solids.
Hydroperoxide titration indicates about 20-30 hydroperoxy
groups per 100 phosphorus atoms, which indicates that a
10 significant number (for example, 70-80%) of the isopropyl
groups of the triaryl phosphate are unreacted and that
the product contains unoxidized original triarylphosphate
molecules as well as triaryl phosphate molecules having
one peroxyalkylaryl group; it is believed, on the basis
15 of statistical probability, that there are also present
triaryl phosphate molecules having two such peroxyalkyl-
aryl groups and some triaryl phosphate molecules having
three such groups. The product is a pale yellow oily
liquid having a viscosity of about 42 centistokes at
20 38 C~ Differential scanning calorimetry of its thermal
decomposition shows a peak at about 230 C (indicating
that its peroxide content is largely hydroperoxide) with
a shoulder in the neighborhood of about 200 C (indi-
cating the presence of peroxy ether groups, which have a
25 lower decomposition temperature than the hydroperoxide
groups).
~XA~PLE 5
This example relates to treatment of high impact
polystyrene whose high impact properties are provided by
30 modification of the polystyrene with a rubber. The
polymer used in this Example is ~DOW Styron 470 impact
- polystyrene" t a polystyrene polybutadiene copolymer
manufactured by Dow Chemical Company. The treatment is
effected on a steam heated, differential speed two-roll
35 ~ompounding mill (135~C front rollr 120-C back roll~O
First the high impact polystyrene is placed on the mill,
forming a sheet on the hotter roll. Then there is added
* Trade Mark
. . ~ . .
-- 8 --
to the sheet, over a period of 10 minutes while milling
continues, 10 parts of additive (as listed below) per
100 parts of polymer; the mixing is continued for another
10 minutes. During the entire period the hot material is
exposed to the atmosphere. The material is then compres-
sion molded (between heated platens) into sheets 75 mils
thick; the sheets are cut into strips for testing burning
time and burning behavior according to nUL-94" test
method. The following results are obtained:
Condition of
hot material
on mill at
end of 20
minute mix- Tg Burning
Additive _ _ing period ( C)* Time (secs)**
(a) None Fluid (plastic) 83
and
93 227
(b) Unoxidized triaryl More fluid than
phosphate of Exam- a but re~ovable 65-
ple 4a fro~ mill 67 80
(c) Same as b plus 1
E~rt c~mene hydro-
peroxide per 100 Less fluid
parts of polymer than b 70 90
(d) Same 25 b plus 3
parts of cumene
hydroperoxide per Slightly more fluid
100 parts of poly- than c 62 123
mer ~`
(e) Peroxidized phos- More fiuid tnan '~
phate of Ex~i~le a but less 75-
4b fluid than b 77 81
* Tg is determined on a "DuPont 9Q0 Differential Thermal Analyzer"
manufactured by E. I. duPont de ~'e~ours ~ Ccmpany.
** Burning time is in seconds (the sl~m o~ ~he b~rniny times of 5
strips in the UL-94 test).
:
_ 9
In the burning te~t all samples drip and ignite the cot-
ton used in the test, but the behavior of e is a little
better in this respect.
Diferential scanning calorimetry (DSC) of the ma-
terials after milling indicates that very little or noperoxide remains; after molding~ DSC shows no evidence
of the presence of peroxide. All samples mold well and
the molded sheets are tough as shown by the fact that
they can be folded back on themselves without breaking.
In the worXing of the polymer on the heated mixing
surfaces (that is, tbe mill rolls) in this Example (and
others below) heat is generated internally by the mixing
forces so that any particular tiny zone within the ma-
terial being mixed the temper~ure may rise, locally, to
above the roll temperature; also, the hot mixing process
occurs in the open air for an appreciable time, which may
promote decomposition of a significant proportion of the
peroxide without reaction of tha~ portion of the perox-
ide (or radicals generated therefrom) with the polymer.
20 This is also indicated by ~he fact that the product con-
tains little if any residual peroxide. It will be
understood that the mixing may be conducted under con-
ditions in which these effects of the atmosphere and of
mixing time are reducedl as in an inert (for example,
nitrogen~ atmosphere or in a closed high speed mixing
apparatus such as a screw e~truder (in which the resi~
dence time may be about 1 to 2 minutes, for example) or
a high torque sigma blade mixing apparatus, so that the
mixed product may retain a significant proportion of
the peroxide enabling the latter to act during, or after~
the shaping of the polymer to its final formO
EX~MPLE 6
This Example relates to treatment of moldable poly-
ethylene. Using the two-roll compounding mill described
in Example 5~ but with both rolls at 132'C, low density
high pressure polyethylene (density 0.924g/cm3, Union Car-
bide Corporation ~DNB-0195 ~atural 7n~ is sheeted on the
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mill, with the gap adjusted to permit a small bead in the
nip of the rolls. Then 6 parts of additive (as listed
below) per 100 parts polyethylene are added slowing drop-
wise over a 20 minute period while milling continues.
5 The materials are then compression molded at 160 C into
sheets 0.75 mm thick, which are tested for horizontal
burning rate. The following results are obtained:
Horizontal
Condition of surning
hot material Rate Burning
Additive on mill (cm/min) Behavior
(a) None Plastic (fluid) 1008 Severe
-- ~ dripping
(b) Unoxidized Becomes increasingly
15 triaryl fluid and at end is
phosphate too sticky to remove
from mill hot. Re- ~
moved by chilling Severe
rolls 8.8 dripping
(c) Peroxida- Appears to "gel"
20 tion pro- locally where drops
duct of of additive contact
phosphate the polymer but then
of b becomes uniform as
milling continues.
Easier to work on
mill, and easier to Moderate
strip off, than a 7.6 dripping
~5
In b the phosphate is a triarylphosphate of a highly iso-
propylated phenol, like that used in Example 1~ below;
the peroxidation product used in c contains about 14 hy-
droperoxyalkyl groups per 100 P atoms (as measured by
3 hydroperoxide titration). Burning rate is measured ac- ¦
cording to ASTM D-635-72 flame test~ ,
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EXAMPLE 7
In a repetition of the milling and molding steps of
Example 6 it is found that when the peroxidized phosphate
is added the polyethylene begins to ball up on the mill
(poor fluxing); good fluxing is obtained by then raising
the roll temperature hy about 5 C It is also found that
the molded product made with the peroxidized phosphate
retains the additive to a mar~edly greater degree than
the product made with the unoxidized phosphate; the lat-
]. ter product has a quite oily surface owing to markedphosphate migration to the surface (~blooming~). This
indicates that aryl phospha~e-containing radicals (such
as a diphe~ylphosphatophenylalkyl rad~cal) may be grafted
to the polyethylene (which has pendent methyl groups)
thus forming a modified polymer which has greater com-
patibility with the unreac~ed aryl phosphate. The
raising of the temperature needed for fluxing may indi-
cate that a limited degree of cross linking of the poly-
ethylene chains has occurred.
EXAMPLE 8
Ordinary general-purpose polystyrene (Union Carbide
Corporation ~GP" polystyrene) is mixed with additiv2s on
a mill as in Example 5, using a front roll temperature
of 135-C and a back roll temperature of 120-C, and then
compres~ion molded into ~heets. The following tabulation
gives the proportions of additives and th~ resultsO
Proportions
Additive a b c d e
3 Poly~tyrene 100 100 100 100 100
Peroxidi zed 9.-
isopropylphenyl
diphenyl phosphate 10
Di Cup R (96%
dicumyl peroxide
manufactured by
~ercules Incorporated) 10 2
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- 12 -
Proportions
Additive a b c d e
Hexabromo-cyclo-
5 dodecane 10 10 10 10
Tg(-C) 80,80 75,76 84,85 93,94 86,87
Oxygen Index 23~9 19.8 20.818.0 21.0
The peroxidized phosphate used in this Example con-
tains (by hydroperoxide titration) about 20 hydroperoxy-
alkyl groups and (by peroxyether titratlons) about 2.3
peroxyether groups per 100 phosphorus atoms~
EXAMPLE 9
(a) ;J~ -7 grams of 4-isopropylph~nyl diphenyl phos-
15 phate is mixed with 1.0 gram of sodium 2-ethylhexanoate.
A stream of oxygen, from a capillary tube, is bubbled
through the mi~ture, maintained at 12S C for 118 hours.
Iodometric kitration of the product indicates 28% conver
sion to 4 (~-hydroperoxy-a-methylethylphenyl) diphenyl
phosphate-
The crude reaction mixture is purified by column
chromatography (silica gel; successive elution with ben-
zene, chloroform and acetone) and the resulting purified
hydroperoxy compound is tested as follows: NMR (CDCl3)
indicates 1.55 (s, 6H, CH3~, 7.13 (s, 14~, aromatic) and
5.93 (s, lH, 00~). The infrared spectrum is nearly iden-
tical to that of the unoxidized starting material except
that it contains the typical O~ band (3300 cm 1) for hy-
droperoxides (cumene hydroperoxide has an OH absorption
at 3380 cm 1) The elemental analysis, calculated for
C21H2106P: C, 63.00; H, 5~29; found: C, 63.32; H, 5.45
The purified compound al~o tests positive for peroxide
activity (starch iodide and acetic acid-isopropyl al-
cohol-sodium iodide). When tested by polarography it be-
haves similarly to cumene hydroperoxide ~-0.B5 volts vs.
SLE for the subject hydroperoxide and -1.1 volts vs. SLE
for cumene hydroperoxide~.
05~
- 13 -
(b) A mixture of 14.2 4-isopropylphenyl diphenyl
phosphate, 40 ml xylene and O.lg sodium 2-ethylhexanoate
is treated as in 9a with oxygen for 119 hours. At this
stage the hydroperoxide titration indicates 42% conver-
sion to hydroperoxide.
(c) A mixture of 50 grams of 4-isopropylphenyl di-
phenyl phosphate and 0.5g sodium formate is treated with
oxygen as in 9a. At various stages hydroperoxide titra-
tions indicate the following conversions to hydro-
peroxide: 28% in 58 hours; 55% in 70 hours, 71% in 72
hours.
(d) A mixture of 10 grams of 4-isopropylphenyl di-
phenyl phosphate, O.lg sodium formate and 5 mg manganese
naphthenate is treated with oxygen as in lla for 30 `
hours. Hydroperoxide titration at this stage indicates
60% conversion to the hydroperoxide. The DSC thermogram
of a solution of 1% of the product in diallyl phthalate
shows two peaks, one at about 230C indicating the pres-
ence (as in Example 9a) of hydroperoxide and the other
at about 200C indicating the presence of peroxyether.
In polarographic tests the material showed activity at
-0.85 volts vs. SLE (as in Example 9a) as well as ac-
tivity at -1.75 volts (representing the activity of the
peroxyether); it should be noted that dicumyl peroxide,
which is a peroxyether, similarly shows polarographic
activity at a lower voltage than cumyl hydroperoxide,
which is the corresponding hydroperoxide (-2.05 volts
for dicumyl peroxide, -1.1 volts for cumene hydroper-
oxide) and that dicumyl peroxide similarly has its peak
exotherm in diallyl phthalate at a lower temperature
(182C) than cumyl hydroperoxide (205C)~
(e) Example 9d is repea~ed except that the dur-
ation of the oxygen treatment is shorter; titration
indicates a 28% conversion to hydroperoxide. The DSC
thermogram of a solution of 1% of the product in di-
allyl phthalate is shown in Fig. 1. It will be seen
that it has two peaks as discussed in 9_.
.. ,. ' , ,. i . :' . :; :
.: ~ : .. :
. .
- 14 -
(f) A triarylphosphate is prepared from a 70:30
mixture of 3-isopropylphenol and 4-isopropylphenol and
is mixed with sodium formate and manganese naphthenate
and then treated with oxygen as in 9a. After 30 hours
the conversion to hydroperoxide (as indicated by hydro-
peroxide titration) is 52%. Since only 30% of the origi-
nal isopropyl groups are 4-isopropyl this degree of con-
version shows that the 3 isopropyl groups are also con-
verted to hydroperoxide.
EXAMPLE 10
_
Phenol is alkylated with different amounts of pro-
pylene, in the general manner described in U~S. patent
3,576,923 to produce mixtures (of phenol and isopropy-
lated phenols) having differing isopropyl contents, the
isopropyl groups being largely in ortho position. The
same, or similar, mixtures are then isomerized in the
manner described in U.S. patent 3,859,395, dated January
7, 1975, to increase their content of m- and p-isopropyl
groups. Each phenolisopropylated phenol mixture is then
20 esterified with POC13 (in the general manner described
in U.S. patent 3,576,923~ to produce a triarylphosphate
and each of these triaryl phosphates is then treated with
oxygen in the general manner described in Example 4b for
25 various periods. In each case hydroperoxide titration
shows formation of hydroperoxides with the conversions
being higher for the phosphates made from the isomerized
alkylates. Some typical results are tabulated belowO
.- , ~ : . .
:
, . . .
-
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- 15 -
Peroxide
Approximate oontent Approximate
Isopropyl oonr Approx~te (hydrcper- Viso~ity
tent (number of Vis ~ it~ oxide group6 after peroxi~
isopropyl group6 before Feroxi- per 100 dation (cenr
per 100 phosphor- dation (centi phosphorus tistokes
5 ous atoms) stokes at 38'C) a~) at 38-C)
(a) 110 6
(b) 110 i~rized 20 28 42
_
(c) 160 30
(d) 160 isomerized 30 37 67
.
(e) 230 50 12
(f) 280 i~rized 50 65 550
-
(g) 270 65 22 160
(h) 310 i~rized 65 40
Particularly in the case of the pho~phat~s made from
the more highly alkylated products, there is a signifi-
cant proportion of molecules of phosphates having two or
more isopropylphenyl groups (for example, in the neigh-
borhood of 80% by weight of such molecules in a phosphate
made from an alkylated phenol having about 310 isopropyl
groups per 100 phosphorus atoms and about 70~ in a phos-
phate having about 280 isopropyl groups per 100 phos-
phorus atoms). The treatment with oxygen is believed ~
convert signif icant proportion of these molecules into
molecules of triaryl phosphate having at lea~t two per-
oxygen groups (for example, hydroperoxyi~opropyl groups)
per molecule.
EXAMPLE 11
.
Tris (4-isopropylphenyl) phosphate is treated with
oxygen at about 125'C and the following conversions tin-
dicated by hydroperoxide tltration~ are obtained after
the following periods of treatment:
'' : ' '`' :: ,
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- 16
- Conversion
thydroperoxyalk
Period groups per 100
(hrs.) phosphorus atoms)
of the tris (4-
isopropylphenyl)
~hosPhate
_
(a) contains 1%
sodium octoate 32 17
~b) contains 1/2%
sodium octoate 31 1/2 43
(c) dissolved in a
triaryl phosphate
of a t-butylated
phenQ~ .(0.33 t-
butyl groups per
phenol~ and con-
tains sodium for-
mate and manganese
naphthenate * 20 1~5
* 10 g of the t-butyl phenyl phosphate, 5 g of the tris
(4-isopropylphenyl~ phosphate, 25 mg sodium formate,
8 drops manganese naphthenate.
In view of the oxidation resis~ance of the t~
butylphenyl groups it is believed that little, if any,
peroxidation of the solvent used in c occurs; this sol-
vent is high boiling and is retained in the product.
The high proportion of hydroperoxide indicates that the
product c must have a relatively high content of tri
aryl phosphate molecules having two or three hydroper-
oxyalkyl groups per molecule. It is probable that such
molecules are also present in a and b.
EXAMPLE 12
10g of phosphate triester are sparged with oxygen
at about 125-C in the presence of sod~um formate and
manganese naphthenat2; the following results are ob-
tained:
- .,,, .
; . , , . . ~- ,.
:: : ;. ~ . .
:: ~
': . ~: :
': , : ' ' ~
~L~LZ~
- 17 -
Period Conversion
Alkylaryl phosphate (hrs.) (as in Example 11)
a. Tris cresyl phosphate
n which the "cresyl"
is largely (85~i) m-
and p-cresols, the
balance being essen-
-tially ethyl phenols
and xylenols 12 8
b. 2-ethylhexyl di (4-
isopropylphenyl) phos-
phate 4 41
c. 2-chloroethyl di (4-
isopropylphenyl) phos-
phate 9 18
d. tris (4-sec-butylphenyl)
phosphate 26 12
15 e. n-butyl di (4-isopro-
pylphenyl) phosphate 20 31
The proportions of sodium formate and manganese naph-
thenate, respectively employed in these runs are (a)
0.1g and 10 mg, (b) 0.1 g and 5 mg, (c) 0.05 g and 5
mg, (d) 0.05g and 5 mg, (e) 0.1g and 5 mg. The DSC
thermogram of a solution of l~i of the product of 12 e
is shown in Figure 2; it will be seen that it has a hy-
droperoxide peak at about 220C and a shou]der at a lower
temperature, indicating the presence of peroxyether.
- EXAMPLE 13
(a) Oxygen is buk,bled through a mixture of 110
grams of 4-isopropylphenyl diphenyl phosphate, 0.6g
of sodium formate and 50 mg of manganese naphthenate
for 5 3/4 hours; hydroperoxide titration indicates that
there are about 37 hydroperoxyalkyl groups per 100 P
atoms. After several months of storage at room temper-
ature analysis by titration indicates that the hydro-
peroxyalkyl content ls substantially unchanged and that
there are about 10 peroxyether groups per 100 P atoms.
(b) Example 13 a is repeated, using, as the phos-
phate, an isopropylated phenyl phosphate like that used
.. O ` `
1~, .
.- . ~ :,
: . ... ,. , :
1 , . : , .
z~
- 18 -
in Example 10g. After 4 3/4 hours of treatment the
product is found (hydroperoxide titration) to contain
about 17 hydroperoxyalkyl groups per 100 P atoms. After
several months storage at room temperature analysis by
titration indicates that there are about 12 hydroperoxy-
alkyl groups per 100 P atoms and substantially no per-
oxyether groups~
(c) Example 13a is repeated, using, as the phos-
phate, an isomerized isopropylated phenyl phosphate like
that used in Example lOb. After 11 hours of treatment
the product is found ~hydroperoxide titration) to contain
about 26 hydroperoxyalkyl groups per 100 P atoms. After
several months' storage at room temperature analysis by
titration indicates that there are about 25 hydroperoxy-
alkyl groups and about 3.4 peroxyether groups per 100 Patoms.
(d) Example 13a is repeated, using, as the phos-
phate, an isopropylated phenyl phosphate like that used
in Example 1Oa (the amount of sodium formate is lg in
20 this case). After 14 hours of treatment the product is
found (hydroperoxide titrationl to contain about 5-hy-
droperoxyalkyl groups per 100 P atoms. After several
months' storage at room temperature analysis by titration
indicates that there are about 4.7 hydroperoxyalkyl and5 0.7 peroxyether groups per 130 P atoms.
EXAMPLE 14
(a) A mixture of 20 grams of 4-isopropylphenyl di-
phenyl phosphate, 100 mg sodium formate and 10 mg mang-
anese naphthenate is sparged with fine bubbles of oxygen
30 fed through fritted glass. During the course of the re-
action samples of the product are analyzed for hydroper-
oxyalkyl and peroxy ether groups; by titration as de-
scribed below. The following results are obtained.
i ~ :
.
: :. : :
~,~
' ~ :
~ 5(~
-- 19
Hydroperoxyalkyl Peroxyether groups
Time groups per per 100 P
(hrs.) 100 P atoms atoms
2 2~.4 0
3 22.5 4.7
4 1~.1 4.8
(b) ~ mixture of 110 grams of triaryl phosphate of
isomerized isopropylated phenol tlike that used in Ex-
ample 1Ob), 0.69 of sodium formate and 50 mg of manga-
nese naphthenate is sparged with oxygen. After 2 hours
treatment little, if any, hydropero~yalkyl formation is
noted (prQsumably due to antioxidant impurities in the
sample) and an additional 50 mg of manganese naphthe-
nate is added. Analysis, as in 1 4A~ gives the following
results:
Time after
addition of
2nd portion
20 f man~anese Hydroperoxyalkyl Peroxyether groups
naphthenate groups per per 100 P
(hrs.) _ _ 100 P atoms atoms
1 1/2 3.7 2.5
2 1/2 10.2 1.8
253 1/2 14.9 4.0
4 1/2 13.4 4.8
(c) A mixture of 110 grams of ~riaryl phosphate ofhighly isopropylated phenyl (like that used in Example
10~)~ 0.6g sodium formate and 5G mg of manganese naph-
thenate is sparged with oxygen~ Analysis as in 14a gives
the following results.
-
., ~ , . ..
, , :,: . - .
: . , , ~ . ...
~,9.Z~
- 20
Hydroperoxyalkyl Peroxyether groups
Time groups per per 100 P
(hrs.) 100 P atoms _ atoms
1 7.9 0.8
3 14.8 5.2
4 17.6 2.3
12.7 10.7
(d) A mixture of 110 grams of triaryl phosphate of
highly isopropylated phenol (like that used in Example
10g), 50 mg of sodium formate and 5 mg cobalt phthalo-
cyanine is sparged with oxygen. After 1 1/2 hours,
little, if any, hydroperoxyalkyl formation is noted and
an additional 500 mg of sodium formate and 50 mg of
cobalt phthalocyanine are added. Analysis as in 14_
gives the following results:
Time after
addition of
2nd portion
of cobalt Hydroperoxyalkyl Peroxyether groups
compound groups per per 100 P
(hrs.) 100 P atoms atoms
1/2 7.2 1.5
3 13.0 12.1
4 1/2 12.5 16.1
EXA~PLE 15
Oxygen is bubbled through a mixture of 10g of an
isopropylated phosphate like that used in Example 10g, ~ -
0.2g of monosodium bis (4-isopropylphenyl) phosphate and
5 mg of manyanese naphthenate for 5 1/2 hours; hydroper-
oxide titration indicates that the product has 14 hydro-
peroxyalkyl group:, per 100 P atoms.
,. . ~ . . . .
: , , : ' ,: ~ , " " .; . :' , ~ : ' . :
`': ' '
9.~L2V~S~
- 21 -
EXAMPLE 16
A product made by oxygen-sparging an isomerized
triaryl phosphate like that used in Example 10_ in the
presence of sodium formate and manganese naphthenate and
having (by hydroperoxide titration) about 19 hydroper-
oxyalkyl groups per 100 P atoms is tested for stability
by storing it at a temperature of about 25C for about
20 weeks in contact with a mass of (a) nickel wire,
(b) stainless steel wire, (c) carbon steel wire. In
each case the hydroperoxyalkyl content remains substan-
tially unchanged.
Conventional techniques may be used for making the
phosphorus compounds used as starting materials. In one
procedure (to make the phosphates of Examples8 and 9)
diphenylphosphochloridate is reacted with 4-isopropyl-
phenyl (or 3-isopropylphenol or mixture of 4-isopropyl-
and 3-isopropylphenol in Example 9_), as follows. To a
stirred solution of 1 gram mole of isopropylphenol and
1.15 gram moles of triethylamine and 700 ml of methylene
chloride in a nitrogen atmosphere, there is added drop~
wise a solution of 1 gram mole of diphenylphosphoro-
chloridate and 500 ml of methylen~ chloride. The tem-
perature is maintained at 0-10C during the addition
which is complete in 1 1/2 to 2 hours. The solution is
then allowed to warm to room temperature and heated to -~reflux overnight. The cooled reaction mixture is slur~
ried with 1 liter of distilled water and washed with 750
ml each of water, 5% aqueous sulfuric acid, 10% aqueous
sodium carbonate and 10% aqueous sodium bicarbonate. The
solution is dried over magnesium sulfate, filtered and
concentrated (rotary evaporator). The crude product is
flash distilled under vacuum with moderate care to remove
the lower boiling fractions (phenols and chloridate) and
then distilled~ under vacuum through a heated packed col-
umn for further purification.
The phosphates of Examples 12_ and e may be produced
by reacting one mole of the alcohol with a mole of POCl3
: . . , ~ . . ~ : ,
- . . .
.:
.
- 22 -
and then reacting the product with the sodium salt of
4-isopropyl phenol. The phosphate of Example 12c may
be produced by reacting ethylene oxide with di (4-
isopropylphenyl) phosphochloridate.
The phenol alkylphenol mixtures produced by partial
alkylation of phenol (as in Examples 4, 10, ll and 13)
are complex mixtures, containing di-alkylated as well as
monoalkylated phenol molecules; see for instance Example
21 of U.S. Patent 3,576,923 and the analyses in Example l
of U.S. Patent 3,859,395. Typical compositions of alkyl-
ates of the types used in Example 10 a,c,e, and g are:
Weight percent of component in
a _ e
Phenol 6039 22 14
2-isopropylphenol 2733 35 30
3- and 4-isopropylphenol 1114 16 19
2,6-diisopropylphenol .2 4 7 5
2,4-diisopropylphenol 1.67 12 16
2,5 and 3,5-diisopropylphenol 2 5 14
2,4,6-triisopropylphenol 1 3 2
2,3,5-triisopropylphenol tr tr tr
On reaction of the alkylphenol-phenol mixture (as such or
after isomerization) with POCl3 there is formed a still
more complex mixture containing triphenyl phosphate mole-
cules, isopropylphenyldiphenyl phosphate molecules with -
isopropyl groups in various positions, di(isopropyl-
phenyl) phenylphosphate molecules with isopropyl groups
in various positions and tris (isopropylphenyl) phosphate
molecules with isopropyl groups in various positions, as
well as molecules containing one, two or even three di-
isopropylphenyl groups.
In the above Examples, dispersed Na salts (formate,
octoate) settle out from the reaction mixture after agi-
tation ceases and may be filtered off; Mn or Co compounds
(when present) remain dissolved in the reaction mixture.
':
'
5~[3
- 23 -
In the hydroperoxide titration mentioned above the
sample is boiled with NaI in a weakly acidified alcohol
solution to liberate iodine. The iodine is then titrated
with sodium thiosulfate as a measure of total hydroper-
oxide content. Specifically, a 100 microliter (0.1 ml)
aliquot of the sample is removed by a syringe and placed
in a 125 ml Erlenmeyer flask. To this is added 10 ml of
anhydrous isopropyl alcohol, 1 ml of acetic acid, and 10
ml of isopropyl alcohol saturated with sodium iodide.
This mixture is refluxed for 10 minutes (at atmospheric
pressure). If the aliquot being tested contains very
little or no peroxide the solution remains colorless or
turns a very pale yellow. With increasing peroxide COIl-
centration the color of the refluxed titration mixture is
yellow, then orange, then brownish orange and sometimes
reddish brown. After the mixture has been heated to re-
flux for 10 minutes, it is cooled to room temperature and
5-10 ml of water added. The solution is then titrated in
conventional manner with 0.01 M sodlum thiosulfate. The
end point is arrived at when the solution turns from pale
yellow to colorless. This is easily determined to within
1-2 drops. Each milliliter of O.OlM sodium thiosulfate
used in the titration represents 0.005 gram mole of hy
droperoxide groups. It is believed that this method does
not indicate that total peroxide content or take into
account the content of peroxyether groups.
In the peroxyether titration mentioned above the
sample is refluxed in an inert atmosphere with acetic
acid containing sodium iodide and a definite amount of
water. Specifically of an aliquot of the sample is taken -
up in deoxygenated xylene (about 1.5 grams of sample per
50 ml xylene) and the resulting solution is added to de-
oxygenated acetic acid, after which 6g NaI in 3 ml deoxy-
genated water are added and the mixture is refluxed under
nitrogen for 30 minutes and then cooled under nitrogen,
mixed with 100 ml of deoxygenated water, swirled to mix
and titrated immediately with 0.1 N sodium thiosulfate
.: . .
., ., ~
, . , . ~ .
~ . .
. .. , , i ~ ~ ~
.2~ 5~
- 24 -
solution. A blank titration is also made to correct for
interfering materials in the reagents. Further details
as to the procedure are set forth in Hercules Inc. Di-Cup
bulletin PRC-205B relating to iodometric assay methods
for dicumyl peroxide; in the titrations yielding the per-
~oxy ether analyses described above, ground glass equip-
ment equivalent to the flask arrangements described in
that bulletin is used; also, the same 93~ reaction factor
is applied.
In the oxygenation process the time needed to attain
a given content of hydroperoxide groups is influenced
considerably by the degree of dispersion of the oxygen.
A small tall body of liquid may undergo rapid reaction
with oxygen supplied from a capillary tube, with the gas
lS bubbles serving also to agltate the mixture. With a
larger body, or a shallower one, mechanical stirring may
be used to promote intimate contact. The use of fine
bubbles of oxygen (such as can be supplied from a porous
fritted-glass outlet) leads to faster results. Increase
in the pressure under which the reaction is conducted
(for example, to 2 atmospheres gauge as compared to the
atmospheric pressure at which the above Examples are con-
ducted) also leads to faster results, presumably because --
more oxygen is dissolved in the reaction mixture. The
oxygen fed to the reaction may be substantially pure
oxygen or it may be in admixture with other materials
which may be substantially inert in the reaction; for ex-
ample, air may be employed. The oxygen may be dry or may
contain moisture; the inclusion of some moisture in the
system (for example, by partly saturating the oxygen with
moisture) has been found to increase the rate of reaction
(perhaps by promoting formation of a hydrated salt of the
pro-oxidant or increasing its tendency to dissolve) but
too high a moisture content appears to inhibit the in-
crease in the desired peroxide content during reaction.
In a preferred embodiment of the process an acidacceptor such as a weak base is present (for example, in
. .
'~
" , " .
h6~05~
- 25 ~
about 0.1 to 5% concentration, preferably about 0.5 or
1%) during the treatment with oxygen. It is believed
that this serves to neutralize acidity present, or
formed, in the reaction mixture. Particularly good re-
sults have been obtained with a dispersed sodium saltof a relatively strong carboxylic acid, such as sodium
formate which is usually substantially insoluble in the
organic phosphorus compound being treated; sodium formate
is known to form aqueous solutions of pH about 7 and to
have a buffering action. Other salts, such as sodium
octoate (for example, 2-ethylhexoate), sodium oleate and
sodium aryl phosphate (as in Example 15) have also been
found to be effective. It is possible that sodium aryl
phosphates or sodium salts of the weakly acidic hydro-
peroxides, or both, are formed in the reaction mixturewhen other sodium salts (for example, sodium formate) are
used as the antacides; in an analysis of a filtered prod-
uct having about 13 hydroperoxyalkyl groups per 100 P
atoms, made from a highly isopropylated triaryl phosphate
like that used in Example 10g, it is found that the acid
number is about 1.6 mg KOH per gram and the sodium con-
tent is in the neighborhood of 500 ppm.
The peroxidation reaction may be speeded up by in-
cluding a small amount of a pro-oxidant, such as suitable
transition metal pro-oxidant compound, preferably soluble
in the phosphorus compound. Good results are obtained
with such compounds as manganese naphthenate (for ex-
ample, a salt which, as in the above Examples, contains ;
about 6% Mn), manganese phthalocyanine, and cobalt
phthalocyanine in an effective metal concentration ofsay, in the range of about 0.0005 to 0.05% such as about
0.003 or 0.006%). It is found that the pro-oxidant re-
duces the induction period without causing rapid de-
composition of the resulting peroxide. As shown in the
Examples above, the pro-oxidant may be permitted to re-
main in the peroxidized mixture in use and no special
separation steps are needed. At times the phosphate
.
, - ' ,; - ' ' , ',
, ...
,z~30~
- 26 -
being treated may contain antioxldant compounds (antioxi-
dant effects may be possibly due, for instance, to sig-
nificant concentrations of lower-boiling impurities such
as unesterified or partially esterified reactan-ts used
to make the phosphate triester) in which case it may be
desirable to add a further quantity of pro-oxidant in
order to start a more rapid peroxidation reaction (as can
be seen in Example 14 _ and d).
The peroxidation reaction may be erfected at room
temperature but it is preferable, particularly in the
initial stages of the reaction, to use elevated temper-
atures, such as within the range of about 100 to 150C,
more preferably about 120 to 130C. The reaction may be
effected at a series of temperatures, such as an initial
higher temperature (for example, above about 120C, for
example, 125 or 130C or higher) to minimize the induc-
tion period and then a lower temperature (for example,
below about 120C such as 115, 110 or 100C or lower~.
The preferred peroxides are those made from com-
pounds having benzylic hydrogen (that is, compounds
having an aliphatic carbon having an abstractable hydro-
gen and directly attached to a carbon of an aryl ring),
the peroxide thus being formed by a process involving
abstraction of that hydrogen and its replacement with an
-00- group. While (as shown in Examples 12a and 2_
above) that carbon atom may carry two or one additional
hydrogen atoms, best results are obtained when the
ring-attached carbon atom is a secondary carbon attached
to two other carbon atoms, as when it is part of an
isopropyl or secbutyl radical. It is believed that t-
butyl radicals, such as are present in Example llc above,
are resistant to peroxide formation so that the t-butyl- --
ated triaryl phosphate of that Example serves as a sub-
stantially inert solvent in the reaction as well as a
flame resistant component (for example, plasticizer) in
the organic plastic to which the mixture is added. It
is believed that molecules of ortho-isopropylated phenyl
.,~ ,, , :
'~ 'n.:
., ,
.. . . :.: .
- 27 -
phosphates, such as 2-isopropylphenyl diphenyl phosphate (pre-
sent, for instance, in relatively large proportions in the
phosphate used in Examples 10 and 13_) serve a similar function;
it appears that there may be steric hindrance, owing to proxi-
mity to the phosphorus-oxy portion of the molecule, that makes
the o-isopropyl substituent resistant to peroxidation. It is
preferred that the peroxidizable alkyl substituent be relative-
ly small, for example, containing less than nine carbon atoms
(more preferably less than six carbons), but it is within the
broader scope of the invention to employ longer substituents
such as those having twelve or eighteen carbon atoms. The sub- ..
stituent is preferably saturated hydrocarbon but it may carry
substituents such as Cl, F, ester (for example, CH3COO-), amide
(for example, NH2CO-) or aryl (for example, phenyl). The aro-
matic ring is preferably a benæene ring and it may have sub-
stituents such as Cl, F, other alkyl (for example, t~butyl),
chloroalkyl, fluoroalkyl, aryl (for example, phenyl~, aralkyl
(for example, benzyl); it may be a condensed ring (for example,
a naphthalene ring).
As illustrated in the above Examples, the phosphorus
compounds to be peroxid.ized are phosphates, such as triaryl
phosphates (which are preferred), monoalkyl diaryl phosphates
~including, of course, compounds having substituents on the
alkyl group as in Example 12_~ or dialkyl monoaryl phosphates.
They may also be another ester (for example, a mixed ester
- 28 -
such as mixed 4-isopropylphenyl phenyl ester or mixed ~-isopro-
pylphenyl methyl ester) of phosphoric acid. Other substituents
may be present as discussed above.
The compounds may be esters of polyhydric alcohols
or polyhydric phenols, such as the mixed ester of phosphoric
acid with propanediol-1,3 and 4-isopropylphenol (for example,
having the formula
O C
/\~
\0/ ~ I
wherein R represents the carbon chain portion of polyhydric
(alcohol). It will be understood that such compounds may have
a plurality of phosphorus atoms, for example, the mixed phos-
phate ester of pentaerythritol and isopropylphenol having the
type formula
1 Il/o-C /C-O\II f
Cl~O` F~ o c/C\ C-O~`P-O~ I :
or the mixed phosphate ester of bis-phenol A and isopropyl~
phenol having the type formula
1 1l IC f==\ O~ Cl
f ~ -O-P-O ~ C ~ ~ cc
C R
~, ~
:
,
- , ' ,
- 29 -
in which R may be aliphat.ic (including cycloaliphatic)
such as methyl, butyl or octyl or aromatic (such as
phenyl or isopropylphenyl).
It is also withi.n the broader scope of the inven-
tion to use, as the phosphorus compound having the per-
oxidizable alkylaryl group, a phosphaæene, such as an
alkylaryloxyphosphazene, for example, a reaction product
of sodium isopropylphenoxide and hexachlorocyclotriphos-
phazene.
It will be understood, of course, that the composi-
tion should be substantially free of amounts of active
peroxide-destabilizing groups which would destroy the
peroxide g~ups by reaction there~ith or by catalytic
action. For instance, the presence of unneutralized or
15 unbuffered active acidic
~-OH groups (or ~P-Cl groups in the pre-
sence of moisture which would form such strongly acidic
20 groups) could prevent formation of the desired peroxide h
content or act to destroy already formed peroxide; also
the presence of certain reducing agents (for example,
phosphites) or amines, or certain concentrations of metal
contaminants could act to destabilize the peroxides. The
25 preferred compositions are sufficiently free of su~h de-
stabilizing materials that on storage (for example, for
at least l day at 27-C and, as indicated in Examples 13
and 16, preferably for well over a week, such as a month
or more at room temperature) they 105e less than 1/3 of
: 30 their peroxide content; more preferably there is sub-
stantially no loss on such storage.
We believe that when isopropylphenyl phosphates of
the type used as plasticizers or hydraulic fluids are
exposed to oxidizing conditions, in such use, traces of
hydroperoxy-alkylphenyl phosphatPs may be formed ini-
tially and that these break down quickly under such oxi-
dizing conditions, possibly owing to the presence of
:
o~5~
- 30 -
sufficient quantities of unbuffered acidic species (for
example, hydrolysis products having
~\ 101
/P-OH groups). The following Example describes
an oxidation in the absence of a buffering agent in the
presence of a pro-oxidant.
EXAMPLE 17
Oxygen is bubbled through a mixture of 42 g of a
triarylphosphate of a highly isopropylated phenol (like
that used in Example 10g above) and 28 mg of manganese
naphthenate at 120-125C for 20 hours. The reaction
mixture turns a dark reddish-brown; hydroperoxide titra-
tion of this mixture indicates that no peroxide is pre-
sent (the titration is carried out under such conditions
that a positive result would be obtained if 2 hydroper-
oxide groups per 1000 phosphorus atoms were present).
As mentioned above, organic peroxides have been used
'! as cross-linking agents, polymerization catalysts, graft-
ing agents and halogen synergists with a wide variety of
polymers. The uses of peroxides are discussed, for in-
stance, in the article of Peroxy Compounds in the Ency-
clopedia of Polymer Science and Technology, Vol. 9, pages
; 827-838 (published by Interscience Publishers, Inc., New
York, N.Y. 10001, United States of America) and the per-
oxy compounds of this invention may be empioyed in those
uses, with the various types of polymers named in that
article. The peroxy compounds of this invention may be
employed as the peroxides in the compositions described
in U.S. patents 3,637,578, dated January 25, 1972,
3,936,414, dated February 3, 1976, and 3,684,616, dated
August 15, 1972. Among the halogen compounds with which
~ 35 the peroxide compounds of this invention may be used as
- synergists are those named in U.S. patents 3,338,864, dated
August 29, 1967, and 3,420,786, dated January 7, 1969.
~) :
:.
'
- 31 -
As mentioned earlier, organophosphorus compounds have
been conventionally employed as -flame retarding additives, for
example, plasticizers, in organic polymers such as polyvinyl
chloride, phenol-Eormaldehyde resins, nylons, acrylic resins,
polystyrene, aminoplasts such as melamineformaldehyde resins,
polyolefins (for example, polyethylene, polypropylene), poly-
urethane foams, other elastomers such as neoprene, cellulose
esters (for example, cellulose acetate or acetate butyrate) and
engineering plastics (for example, polyphenylene oxide). The
peroxy compounds and mixtures of this invention may be used
in the same way. They may be similarly included in other poly-
mers such as polycarbonates (for example, polycarbonates of
bis- phenol A) or ABS polymers (acrylonitrilebutadiene-styrene
-copolymers, including block and graft copolymers).
The proportions of the peroxy-containing phosphorus
compounds will depend, of course, on the intended use and will
generally be more than 0.1% and less than 50% oE the weight
of the polymer.
The conditions used for obtaining the thermograms of
Figs. 1 and 2 are as follows: The instrument used is a Dupont
900 Differential Thermal Analyzer set at: T; 50C/inch, ~Tr
0.5C/inch, and Rate 20C/minute. Sample sizes are 5-10 mg.
,p
: ':
