Note: Descriptions are shown in the official language in which they were submitted.
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078002-M - 1 -
Bis-(Piperidinyl)Pentite
This invention relates to the stabilization of polymers.
More particularly, it relates to the stabilization of olefin
polymers against the deteriorating influence of ultraviolet
radiation.
Ultrav;olet light has a degradative effect on olefin
`polymers, the severity of which is dependent on the particular
polymer and the geographical location of exposure. The degradation
-may take the form of discoloration, loss of tensile and impact
strength, distortion of initial flexibility, dimensional change,
surface craze, cracking, powdering or increased electrical con-
ductivity. All of these effects may result from the breaking of
carbon-to-carbon bonds in the po1ymer chain followed by immediate
oxidation of the chain fragments.
`15 . It is well known that the addition of certain materials
to an olefin polymer will impart a degree of stabilization to
that polymer with respect to its resistance to the destructive
forces of ultraviolet radiation. These materials, in one instance,
function as preferential acceptors of incident ultraviolet
radiation because they have a much higher affinity for such
` radiation than does the olefin polymer. ~t appears that they
;~ absorb harmful radiation and dissipate it as harmless energy.They thus form a protective shield for the polymer in which they
are present.
U.S. 3S640,928 (Murayama et al.) shows the stabilization
of synthetic polymers by the presence therein of certain piperidine
compounds wherein the ~wo carbon atoms adjacent to the ring
nitrogen each contain two alkyl substituents. The piperidi:ne
compounds contain also an oxy substituent in the four-position and,
in many instances, two or more piperidine nuclei are joined to
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078002-M - 2 -
one another by means of polyfunctional ether, ester, carbamate,sulfonate, etc. groups.
West German Patent No. 2,500,314 (Ciba-Geigy) like-
wise shows the stabilization of polyolefins (which contain
inorganic pigments) by means of substituted piperidines. The
broad description (and most pertinent disclosure) of the in-
ventions is found on pages 2 and 6 and in Claim 1.
Japanese Patent Publication No. 1977-22578, published
February 19, 1977, shows the stabilization of a wide variety of
organic materials, including "synthétic resins" (page 1) such as
"polypropylene" (page 11), by means of any of a large number of
organic phosphites, including substituted pentites, i.e., penta-
erythritol diphosphites. Formula No. ~2 on page 8 is pertinent.
The stabilized polymer compositions of the present in-
vention comprise olefin polymers stabilized against deterioration
due to ultraviolet light and heat by the presence therein of a
. minor proportion, sufficient to provide such stabiliza~ion, of
- an additive which is 3,9-bis(2,2,6,6-tetramethyl-4-piperidinyloxy)-
2,4,8,10,3,9-tetraoxadiphospha(5,5)spiroundecane or a salt thereof.
The structural formula of this compound is as follows:
(CH3 ~ C- C ~ / OC ~ / CH20 \ / CH2 C \H3)2
HN \ / CHOP \ / C POCH / NH
(CH3)2C' CH2 OCH2 CH20 CH2--C~CH3)2
Salts of the above compound are, as indicated, also
contemplated. These include inorganic acid salts such as phosphate,
- carbonate and the like, as well as organic acid salts such as citrate, stearate, benzoate and the like.
The olefin poiymers contempalted herein ;nclude homo-
polymers and copolymers of monoolefins, preferably those monoolefins
con~aining 1 4 carbon atoms. Illustratlve examples include
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078002-M 3
polyethylene (both low and high density), polypropylene, poly-
isobutylene, and copolymers of ethylene, propylene and iso-
butylene; EPDM polymers are also contemplated. Polypropylene
is preferred.
The amount of the above additive which should be used in
the polyolefin compositions of this invention may vary widely
depending upon the type, properties and particular uses of the
polyolefin to be stabilized. In general, it is added to the poly-
olefin in such amount as to provide a concentration of from about
0.01% to about 5.0% based on the eight of polyolefin, preferably
~rom about 0.05% to about 2.0%. It may be used as above, i.e.,
as the only additive in the polymer composition, but generally it
will be used in combination with one or more additives.
Other such additives include metal soaps such as
calcium, zinc, barium, cadmium, tin, magnesium and aluminum soaps,
i.e., polyvalent metal salts of fatty acids. These coact with the
additive of this invention to impart improved properties to
olefin polymers upon prolonged exposure to atmospheric conditions.
They should each be used, when such use is indicated, in con-
centrations of from about 0.05% to about 3.0%,based on the weightof olefin polymer.
Phenolic antioxidants may also be used in combination
with the nitrogen compound of this invention. Those phenolic
antioxidants embraced by the structural formula:
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R>~
HO ~ CH2CHCOO - ~ A
_ _ n
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078002-M - 4 -
~ere R and R' are lower alkyl, i.e., al~yl of 1-10 carbon atoms,
R" is lower alkyl or hydrogen, n is 1-4, and A is the residue
I of an alkanol or alkane polyol, are preferred. Illustrative
` examples of A include
CH
~; CH2 - C - CH2, C18H37, CH2CH2, CH2CHCH2, and (CH3)2C
CH2
~' .
A contains 2-24 carbon atoms. Preferably, A is C18H37. The
- relative proportions of antioxidant used in the stabilized poly-
olefins of this invention range from about 0.01% to about 3.0%,
; based on the polyolefin.
Other additives contemplated herein include phosphites,
fillers, pigments, antistatic agents, etc.
The above add;tive rnay be prepared by reaction of 4-
hydroxy-2,2,6,6-tetramethylpiperidine with bis(3,9-dimethylamino)-
2,4,8,10,3,9-tetraoxadiphospha(5,5)spiroundecane, according to the
-,`~ following equation:
;~ (CH3 ~C C ~ / OC ~ j CH2 \
~ HN \ / CHOH (CH3)2N-P \ / C \ P-N(CH3)2 >
,~ ~ (CH3)2C CH2 OCH2 CH20
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HN ~ ~ 'HO P / ~ / 2 \ / 2 5 3)2 + 2(CH3) NH
, ~ (CH3)2C CH2 \OCH2 CH2 ' CH2~C(CH3)2
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07~002-M _ 5 _
Alternatively, bis(3,9-dimethoxy)- or bis(3,9-diphenoxy)-2,4~8,
10,3,9-tetraoxadiphospha(5,5)spiroundecane may be substituted
in the above e~uation for the bis(3,9-dimethylamino)-compound,
also, the bis(3,9'dichloro)- compound may be used in such a
reaction, in ~hich case a hydrogen chloride acceptor is required,
e.g., triethyl amine. The method illustrated above, however,
is preferred because the reaction proceeds smoothly, with good
yields, and the resulting product is easily isolated and purified.
The method of preparation is illustrated by the follow-
ing example:
'Example
A mixture of 12 grams (0.0425 mol) of II (in the aboveequation) and 16 grams (0.1019 mol) of 4-hydroxy-2,2,6,6-tetra-
methylpiperidine (I) is heated with stirring in a nitrogen at-
mosphere at 15~C until 3.4 grams (9OY0 of the theory) ofdimethyl amine is collected (by means of a methanol-dry ice
condenser). Then, the unreacted piperidine compound is distilled
away by continued heating at 150~C/20 mm. The cooled residue
is warmed and stirred wi~h 75 ml. of heptane, then filtered.
The cooled filtrate deposits 16 grams of a solid, M.P., 133-138C.
Evaporation of the riltrate from this crystallization yields an
. additional 2 grams, M.P. 9 128-136C.
The efficacy of the additive of this invention as a
stabilizer against detericration of polymers caused by ultra--
violet light is shown by data obtained from tests carried out ina h'eather-Ometer. Test samples are prepar~d by dry-blending in
a Waring elendor and then extruding from ~ raber,der extruder
havin~ a 3/4-inch screw diameter. A sheet die is used which
can be adJusted to produce a film 10 mils thick and 2 inches
wide. The extruder is heated so that the temperature of the
extruded film is about 500F as it leaves'the die. The éxtruded
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078002 ~ - 6 -
material is pulled by a set of chrome rolls which are heatPd atabout 50C and which polish the film and assure its uniform
thickness. Care is taken not to pull the film too fast as it
leaves the extruder so that the polymer remains unoriented.
The extrusion of polypropylene under these conditions produces an
extrudate having a tensile strength of about 5000 psi.
The Weather-Ometer is an enclosed box containing xenon
lamps, the light from whicn simulates the ultraviolet radiation
from the sun. Water is sprayed on the test samples, so as to
simulate rain, for 20 minutes of each hour. The test samples
are suspended in this environment by means of metal clamps and
removed at periodic intervals for testing as regards deterioration
Gf tensile strength.
Three test samples are tested each time and the average
result of these three is taken as the tensile strength. They
are pulled at a rate oF ten inches per minute on an Instron,
which records the stretch or elongation of the sample and the
force required to produce that elongation. When the sample
yields and again when it breaks, the force and elongation are
no'ed. The force (in pounds) is divided by the cross^sectional
area (in square inches) to give the tensile strength. When the
tensile stren~th has diminished to 50% of the original value,
the sample is rated a failure.
The product of the Example is subjected to such testing
at periodic intervals after exposure to ultraviolet light in the
Weather-Ometer as above. The formulation (A) tested consisted of
100 parts of polypropylene containing 0.05 part of calcium stearate,
0.1 part of~Irganox 1076 (octadecyl-3-(3',-5'-ditertiarybutyl-4'-
hydroxyphenyl)propionate), and 0.3 part of the product of the
Example. A second sample (B) is prepared and tested, of similar
composition, except that it contains no product of the Example.
The resu1ts are as follows:
: ......................................................................................................................................................
333
078002-M _ 7
' TABLE I
Time'to Failure
A 4150 hours
B 700 hours
Similar tests on formulations containing varying
proportions of the additive of this invention are rated somewhat
' differently. The test samples are 2.5 mils thick and are analyzed
for carbonyl content (a measure of relative deterioration) by
means of infrared curves. That is, the area under the peak at
5.8 microns is tàken as a quantitative indication of the carbonyl
content of the test sample. When the test sample is shown to have
~; ~ developed an inc~ease of 0.1 percent in carbonyl content, it is
; regarded as havinq failed and the hours of exposure in the
Weather-Ometer until such failure is a measure of the efficacy
~ ~ 15 of the test sample as an ultraviolet stabilizer. The test
'~ samples in Table II each contain 100 parts of polypropylene,
-~ ~ 0.10 part of Irganox 1076, O.lO'part of distearyl pentaerythritol
~ diphosphite and varying proportions (or none), as indicated, of
;- the additive `of the invention.
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` ~ ' 20 TABLE'II
Sample ''Product of'the'Example ''Time to Failure
C O ~ 35 hours
D 0.25 ~ 275 hours
E ~ 0.50 275 hours
All parts and pércentages herein are by weight
unless otherwise speclfically defi~ned.
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