Note: Descriptions are shown in the official language in which they were submitted.
~2~
-- 2 --
The present invention pertains to alkane or
cycloalkane moieties containing two substituted
hydroxyphenylthio groups which are useful as stabilizers
for organic materials and to stabilized compositions
containing said compounds.
~ackground of the Invention
_ _ _ _
Organic polymeric materials such as plastics, rubber
and resins, and synthetic, lubricating and mineral oils are
subject to thermal, oxidative and photo~degradation. A
great variety of stabilizers are known in the art for
stabilizing a diversity of substrates. Their effectiveness
varies depending upon the causes of degradation and the
substrate stabilized. In general, it is difficult to
predict which stabilizer will be most effective and most
economical for any one area of application. For example,
stabilizer effectiveness in reducing volatility may depend
upon preventing bond scission in the substrate molecule.
Limiting embrittlement and retaining elasticity in a
polymer or rubber ~ay require prevention of excessive
crosslinking and/or chain scission. Prevention of
discoloration may require inhibiting reactions which yield
.,
l;~S~O
new chromophores or color bodies in the substrate or
stabilizer. Problems of process stability and
incompatibility must also be consideredO These and other
undesirable degradative effects may originate as a result
of thermal degradation, oxidation, photodegradation or some
combination of these processes with the organic materials
under conditions which are not well understood.
It has now been determined that the compounds of
this invention possess an unusual combination of desirable
properties which makes them particularly effective and
useful as stabilizers. The compounds are particularly
effective in protecting polyolefins, high impact
polystyrene, rubbers such as polybutadiene and
styrene-butadiene rubber, and other elastomers wherein
retention of elasticity and inhibition of crosslinking,
crazing, discoloration, odor formation and exudation are
basic requirements.
Some of the hydroxyphenylthio compounds found useful
in stabilizing organic substrates are known.
A related series of ~.S. Patent Nos. 3,576,883;
3,786,100; 3,897,500 and 3,956,359 disclose keto
substituted alkylidenedithiobisphenols wherein bis(3,5-
di-tert-butyl-4-hydrophenyl) groups and various alkylidene
bridging groups are present. In all cases a methyl
substltuent must appear on the alkylidene linking member of
these compounds. The compounds of these patents are found
useful for reducing blood cholesterol levels in
warm-blooded animals and no mention or suggestion of their
possible use as stabilizers is made.
12S~
-- 4 --
M.B. Neuworth et al., J. Medicinal Chemistry, 13,
722 (1970) describes the same compounds as disclosed in the
four patents mentioned supra as well as a number of
comparable alkylidenedithiophenols having a variety of
substituent groups on the phenyl ring and on the linking
alkylidene member. Again, the only utility given for said
compounds is for hypocholesterolemic activity in
warm-blooded animals.
Three Japanese Kokai 79/163,536; ~n/9,041 and
80/17,316 (CA, 93, 71280x (1980); CA, 93, 94980q (1980) and
CA, 93, 149970u (1980) respectively) describe
2,2-bis(3,5-di-tert-butyl-4-hydroxyphenylthio)propane as a
hypocholesterolemic agent.
U.S. Patent No. 3,704,327 discloses bis(3-methyl-5-
tert-butyl-4 hydroxyphenylthio)methane and 1,1-bis(3-
methyl-5-tert-butyl-4-hydroxyphenylthio)ethane as
antioxidants for rubber. The instant compounds differ
structurally from these prior art compounds by being
substituted on the phenyl ring by two tert-butyl groups
ortho to the hydroxy in each ring and hy having the
alkylidene linking member substituted by a total of at
least five carbon atoms. The instant compounds provide
b~tter stabilization performance in a variety of substrates
than do the two prior art compounds of ~.S. 3,704,327.
Objects of the Invention
It is the primary object of this invention to
provide a class of hydroxyphenylthio compounds which
exhibit a broad range of improved stabilization performance
characteristics.
~2~
It is a further object to provide a group of novel
compounds within the above-noted class.
.Detailed Disclosure
The instant invention pertains to organic materials
stabilized against the deleterious effects of thermal,
oxidative and photo-degradation by the incorporation
therein of an effective amount of a compound of formula I
L ~ ~ 2 (I)
wherein
R is tert-butyl,
Rl is hydrogen or a straight- or branched-chain
alkyl of 1 to 4 carbon atoms,
R2 is a straight- or branched-chain alkyl of 6 to 8
carbon atoms, cyclohexyl, cyclohex-3-enyl or 3,5-di-tert-
butyl-4-hydroxyphenyl; or
R1 and R2 together are alkylene of 5 to 11 carbon atoms.
When R1 is a straight- or branched-chain alkyl of 1
to 4 carbon atoms, Rl is, for example, methyl, ethyl,
isopropyl, n-propyl, isobutyl and the like.
When R2 is a straight- or branched-chain alkyl of 6
to 8 carbon atoms, R2 is, for example, n-hexyl, 2,4-dimethyl-
amyl, 3-heptyl and the like.
When Rl and R2 together are alkylene of 5 to 11
carbon atoms, they are, for example, pen~amethylene,
hexamethylene, heptamethylene or undecamethylene and the
like.
Preferably Rl is hydrogen or methyl.
When Rl and R2 together are alkylene, Rl and R2
together are preferably pentamethylene~
The stabilizer compounds are prepared by reacting
the appropriate 4-mercaptophenol with the appropriate
carbonyl compound in the presence of a strong acid
catalyst, such as hydrogen chloride. The reaction is
preferably conducted in an inert organic solvent, such as
methanol, heptane, benzene or toluene. The reaction
temperature generally ranges from 0 to 100C. The starting
materials are generally items of commerce or can be
prepared by known methods.
Compounds of this invention are particularly
effective in stabilizing organic materials such as
plastics, polymers and resins in addition to mineral and
synthetic fluids such as lubrlcating oils, circulating
oils, etc.
Substrates in which the compounds of this invention
are particularly useful are polystyrene, including impact
polystyrene, ABS resin, SBR, polyisoprene, as well as
natural rubber, polyesters including polyethylene
terephthalate and polybutylene terephthalate, including
copolymers, poly-alpha-olefins and lubricating oils such as
those derived from mineral oil.
In general, polymers which can be stabili2ed
include:
1. Polymers of mono~lefins and diolefins, for
example polyethylene (which optionally can be crosslinked),
polypropylene, polyisobutylene, polybutene-l,
polymethylpentene-l, polyisoprene or polybutadiene, as well
as polymers of cycloolefins, for instance of cyclopentene
or norbornene.
2. Mixtures of the polymers mentioned under 1), for
example mixtures of polypropylene with polyethylene or with
polyisobutylene.
3. Copolymer of monoolefins and diolefins with each
other or with other vinyl monomers, such as, for example,
ethylene/propylene, propylene/butene-l, propylene/isobuty-
lene, ethylene/butene-l, propylene/butadiene,
isobutylene/isoprene, ethylene/ethyl acrylate, ethylene/
alkyl methacrylates, ethylene/vinyl acetate or
ethylene/acrylic acid copolymers and their salts (ionomers)
and terpolymers of ethylene with propylene and a diene,
such as hexadiene, dicyclopentadiene or ethylidene
norbornene.
9 ~L O
4. ~olystyrene.
5. Random copolymers of styrene or ~-methylstyrene
with diene~ or acrylic derivatives, such as, for example,
styrene/butadiene, styrene/acrylonitrile, styrene/alkyl
methacrylates, styrene/acrylonitrile/methyl acrylate;
mixtures of high impact strength from styrene copolymers
and another polymer, such as, for example, from a
polyacrylate, a diene polymer or an ethylene/propylene/
diene terpolymer; and block copolymers of styrene, such as,
for example, styrene/butadiene/styrene, styrene/isoprene/
styrene, styrene/ethylene/butylene/styrene or styrene/
ethylene/propylene/styrene.
60 Graft copolymers of styrene, such as, for
example, styrene on polybutadiene, styrene and
acrylonitrile on polybutadiene, styrene and alkyl acrylates
or methacrylates on polybutadiene, styrene and
acrylonitrile on ethylene/propylene/diene terpolymers,
styrene and acrylonitrile on polyacrylates or polymeth-
acrylates, styrene and acrylonitrile on acrylate/butadiene
copolymers, as well as mixtures thereof with the copolymers
listed under 5), for instance the copolymer mixtures known
as ABS-, MBS-, ASA- or AES-polymers~
7. Halogen-containing polymers, such as polychloro--
prene, chlorinated rubbers, chlorinated or sulfochlorinated
polyethylene, polymers from halogen-containing vinyl
compounds, as for example, polyvinyl chloride, polyviny-
lidene chloride, polyvinyl fluoride, polyvinylidene
fluoride, as well as copolymers thereof, as for example,
vinyl chloride/vinylidene chloride, vinyl chloride/vinyl
acetate or vinylidene chloride/vinyl acetate copolymers.
~ 2 S L~
g
8. Polymers which are derived from ~,~-unsaturated
acids and derivatives thereof, such as polyacrylates and
polymethacrylates, polyacrylamides and polyacrylonitrile.
9. Copolymers from the monomers mentioned under 8)
with each other or with other unsaturated monomers, such
as, for instance, acrylonitrile/butadiene, acrylonitrile/
alkyl acrylate or ~crylonitrile/vinyl chloride copolymers
or acrylonitrile/alkyl methacrylate/butadiene terpolymers.
10, Polymers which are derived from unsaturated
alcohols and amines, or acyl derivatives thereof or acetals
thereof, such as polyvinyl alcohol, polyvinyl acetate,
polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate,
polyvinylbutyral, polyallyl phthalate or polyallylmelamine,
11. Homopolymers and copolymers of cyclic ethers,
s~lch as polyalkylene glycols, polyethylene oxide, poly-
propylene oxide or copolymers thereof with bis-~1ycidyl
ethers,
12. Polyacetals, such as polyoxymethylene and those
polyoxymethylenes which contain ethylene oxide as a
comonomer.
13, Polyphenylene oxides and sulfides.
.
14. Polyurethanes which are derived from
polyethers, polyesters or polybutadienes with terminal
hydroxyl groups on the one side and aliphatic or aromatic
polyisocyanates on the other side, as well as precursors
thereof.
91~
-- 10 --
15. Polyamides and copolyamides which are derived
from diamines and dicarboxylic acid and/or from aminocar
boxylic acids of the corresponding lactams, such as
polyamide 4, polyamide 6, polyamide 6/6, polyamide 6/10,
polyamide 11, polyamide 12, poly-2,4,4-trimethylhexamethy-
lene terephthalamide or poly(m-phenylene isophthalamide),
as well as copolymers thereof with polyethers, such as for
instance, with polyethylene glycol, polypropylene glycol or
polytetramethylene glycols.
16. Polyureas, polyimides and polyamide-imides.
17, Polyesters which are derived from dicarboxylic
acids and dialcohols and/or from hydroxycarboxylic acids or
the corresponding lactones, such as polyethylene tereph-
thalate, polybutylene terephthalate, poly-1,4-dimethylolcy-
clohexane terephthalate and polyhydroxybenzoates as we11 as
block copolyether-esters derived from polyethers having
hydroxyl end groups.
18. Polycarbonates.
19. Polysulfones and polyethersulfones.
20. Crosslinked polymers which are derived from
aldehydes on the one hand and phenols, ureas and melamines
on the other hand, such as phenol/formaldehyde resins,
urea/formaldehyde resins and melamine/formaldehyde resins.
21. Drying and non-drying alkyd resins.
22. i~nsaturated polyester resins which are derived
from copolyesters of saturated and unsaturated dicarboxylic
acids with polyhydric alcohols and vinyl compounds as
crosslinking agents, and also halogen-containing
modifications thereof of low flammability.
23 Thermosetting acrylic resins, derived from
substituted acrylic esters, such as epoxy-acrylates7
urethane-acrylates or polyester-acrylates.
24. Alkyd resins, polyester resins or acrylate
resins in admixture with melamine resins, urea resins,
polyisocyanates or epoxide resins as crosslinking agents.
25. Crosslinked epoxide resins which are derived
from polyepoxides, Eor example from bis-glycidyl ethers or
from cycloaliphatic diepoxides and aromatic diepoxides~
26. Natural polymers, such as cellulose, rubber,
gelatin and derivatives thereof which are chemically
modified in a polymer-homologous manner, such as cellulose
acetates, cellulose propionates and cellulose butyrates, or
the cellulose ethers, such as methyl cellulose,
27. Naturally occurring and synthetic organic
materials which are pure monomeric compounds or mixtures of
such compounds, for example mineral oils, animal and
vegetable ~ats, oils and waxes, or oils, fats and waxes
based on synthetic esters (e.g. phthalates, adipates,
phosphates or trimellitates) and also mixtures of synthetic
esters with mineral oils in any weight ratios~
310
~ 12 -
which materials may be used as plasticizer for polymers or
as textile spinning oils, as well as aqueous emulsions of
such materials.
28. Aqueous emulsions of natural or synthetic
rubber, e.g. natural latex or latices of carboxylated
styrene/butadiene copolymers.
In general, the stabilizers of this invention are
employed in from about 0.01 to about 5% by weight of the
stabilized composition, although this will vary with the
particular substrate and application. An advantageous
range is from about 0.05 to about 2~, and especially 0.1 to
about 1~.
The stabilizers of the instant invention may readily
be incorporated into the organic polymers by conventional
techniques, at any convenient stage prior to the
manufacture of shaped articles therefrom. For example, the
stabilizer may be mixed with the polymer in dry powder
form, or a suspension or emulsion of the stabilizer may be
mixed with a solution, suspension, or emulsion of the
polymer. The stabilized polymer compositions of the
invention may optionally also contain various conventional
additives, such as the following:
~z~ o
- 13 -
_. Antioxidants
1.1, Alkylated monophenols, for example,
2,6-di-tert-butyl-4-methylphenol
2-tert-butyl-4,6-dimethylphenol
2,6-di-tert-butyl-4-ethylphenol
2,6-di-tert-butyl-4-n-butylphenol
2,6-di-tert-butyl-4-i-butylphenol
2,6-di-cyclopentyl-4-methylphenol
2-(~-methylcyclohexyl)-4,6-dimethylphenol
2,6-di-octadecyl-4-methylphenol
2,4,6-tricyclohexylphenol
2,6-di-tert-butyl-4-methoxymethylphenol
1.2. Alkylated hydroquinones, for examp,le
2,6-di-tert-butyl-4-methoxyphenol
2,5-di-tert-butyl-hydroquinone
2,5-di-tert-amyl-hydroquinone
2,6-diphenyl-4-octadecyloxyphenol
1.3. Hydroxylated thiodiphenyl ethers, for example
2,2'-thio-bis-(6-tert-butyl-4-methylphenol)
2,2'-thio-bis-(4-octylphenol)
4,4'-thio-bis-(6-tert-butyl-3-methylphenol)
4,4'-thio-bis-(6-tert-butyl-2-methylphenol)
~s~
1.4. Alkylidene-bisphenols, for example,
2,2'-methylene-bis-(6-tert-butyl-4-methylphenol)
2,2'-methylene-bis-(6-tert-butyl-4-ethylphenol)
2,2'-methylene-bis-[4-methyl-6-(~-methylcyclohexyl)-phenol]
2,2'-methylene-bis-(4-methyl-6-cyclohexylphenol)
2,2'-methylene-bis-(6-nonyl-4-methylphenol)
2,2'-methylene-bis-[6-(~-methylbenzyl)-4-nonylphenol]
2,2'-methylene-bis-[6-(~,~-dimethylbenzyl)-4-nonylphenol]
2,2'-methylene-bis-(4,6-di-tert-butylphenol)
2,2'-ethylidene-bis-(4,6-di-tert-butylphenol)
2,2'-ethylidene-bis-(6-tert-butyl-4-isobutylphenol)
4,4'-methylene-bis-(2,fi-di-tert-butylphenol)
4,4'-methylene-bis-(6-tert-butyl-2-methylphenol)
1,1-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-butane
2,6-di-(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-
methylphenol
1,1,3-tris-(5-tert-butyl-4-hydroxy-2-methylphenyl)-butane
1,1-bis-(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-
dodecylmercaptobutane
ethylenglycol-bis-[3,3-bis-(3-tert-butyl-4-hydroxy-
phenyl)butyrate]
di-(3-tert-butyl-4-hydroxy-5-methylphenyl)-dicyclo-
pentadiene
di-[2-(3-tert-butyl-2-hydroxy-5-methyl-benzyl)-6-tert.-
butyl-4-methylphenyl] terephthalate.
1.5. Benzyl compounds, ~or exam~le,
1,3,5-tri-(3,5-di-tsrt-butyl-4-hydroxybenzyl)-2,4,6-
trimethylbenzene
bis-(3,5-di-tert-butyl- 4-hydroxybenzyl) sulfide
3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetic acid
isooctyl ester
bis-(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)dithiol-
terephthalate
1,3,5-tris-(3,5-di-tert.butyl-4-hydr~xybenzyl) isocyanurate
1,3,5-tris-(4-tert.butyl-3-hydroxy-2,6-dimethylbenzyl)
isocyanurate
3,5-di~tert-butyl-4-hydroxybenzyl-phosphoric
acid dioctadecyl ester
3,5-di-tert-butyl-4-hydroxybenzyl-phosphoric acid monoethyl
ester, calcium-salt
1.6. Acylaminophenols, for example,
4-hydroxy-lauric acid anilide
4-hydroxy-stearic acid anilide
2,4-bis-octylmercapto-6-(3,5-tert.butyl-4-hydroxyanilino)-
s-triazine
octyl-N-(3,5-di-tert.butyl-~-hydroxyphenyl)-carbamate
1.7. Esters o~ ~-(3,5-di-tert-butyl-4-hydroxyphenyl)-
propionlc acid with monohydric or polyhydric alcohols, for
example,
methanol diethyleneglycol
octadecanol triethyleneglycol
1,6-hexanediol pentaerythritol
neopentylglycol tris-hydroxyethyl isocyanurate
thiodiethyleneglycol di-hydroxyethyl oxalic acid
diamide
1.~. Ester of ~-(5-tert-butyl-4-hydroxy-3-methylphenyl)-
propionic acid with monohydric or polyhydric alcohols, for
example,
methanol diethyleneglycol
octadecanol triethyleneglycol
~Z~ LO
- 16 -
1,6-hexanediol pentaerythritol
neopentylglycol tris-hydroxyethyl isocyanurate
thiodiethyleneglycol di-hydroxyethyl oxalic diamide
l.9. Amldes of ~-~3,5=di-tert-butyl-4-hydroxyphenyl)-
propionic acid for example,
N,N'-bis-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-
hexamethylenediamine
N,N'-bis-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-
trimethylenediamine
N,N'-bis-(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)-
hydrazine
2. UV absorbers and light stabilisers
2.1. 2-(2'-Hydroxy~henyl)-benztriazoles, for example, the
S'-methyl-, 3',5'-di-tert-butyl-, 5'-tert-butyl-,
5'-(1,1,3,3-tetramethylbutyl)-, 5-chloro-3',5'-di-tert
butyl-, 5-chloro-3'-tert~butyl-5'-methyl-, 3'-sec-butyl-
5'-tert-butyl-, 4'-octyloxy, 3',5'-di-tert-amyl-,
3',5'-bis-(~,~-dimethylbenzyl)-derivative.
2.2._2-Hydroxy-benzophenones, for example, the 4-hydroxy-,
4-methoxy-, 4-octyloxy, 4-decyloxy-, 4-dodecyloxy-
~4-benzyloxy, 4,2',4'-trihydroxy- and
2'-hydroxy-4,4'-dimethoxy derivative.
~25 ~LO
- 17 -
2.3. Ester of optionally substituted benzoic acids for
example, phenyl salicylate, 4-tert-butylphenyl salicylate,
octylphenyl salicylate, dibenzoylresorcinol, bis-(4-tert-
butylbenzoyl)-resorcinol, benzoylresorcinol, 3,5-di-tert-
butyl-4-hydroxybenzoic acid 2,4~di-tert-butyl-phenyl ester
and 3,5-di-tert-butyl-4-hydroxybenzoic acid hexadecyl
ester.
2.4. Acrylates, for example, ~-cyano~ diphenylacrylic
acid ethyl ester or isooctyl ester, ~-carbomethoxy-cinnamic
acid methyl ester, ~-cyano-~-methyl-p-methoxy-cinnamic acid
methyl ester or butyl ester, a-carbomethoxy-p-methoxy-
cinnamic acid methyl ester, N-(~-carbomethoxy-~ cyano-
vinyl)-2-methyl-indoline.
2.5 Nickel compounds, for example, nickel complexes of
2,2'-thio-bis-[4-(1,1,3,3-tetramethylbutyl)-phenol], such
as the 1:1 or 1:2 complex, optionally with additional
ligands such as n-butylamine, triethanolamine or N-cyclo-
hexyl-di-ethanolamine, nickel dibutyldithiocarbamate,
nickel salts of 4-hydroxy-3,5-di-tert-butylbenzylphosphonic
acid monoalkyl esters, such as of the methyl, ethyl or
butyl ester, nickel complexes of ketoximes such as of
2-hydroxy-4-methyl-phenyl undecyl ketoxime, nickel
complexes of l-phenyl-4-lauroyl-5-hydroxy-pyrazol,
optionally with additional lisands.
2.6. Sterically hindered amines, for example bis-(2,2,6,6-
tetramethylpiperidyl) sebacate, bis-(1,2,2,6 r 6-pentamethyl-
piperidyl) sebacate, n-butyl-3,5-di-tert-butyl-4-hydroxy-
benzyl malonic acid bis-(1,2,2,6,6-pentamethylpiperidyl)-
ester, condensation product of l-hydroxyethyl-2,2,6,6-
1~4~3~L~
- 18 -
tetramethyl-4-hydroxypiperidine and succinic acid,
condensation product of N,N'-(2,2,6,6-tetramethyl-
piperidyl)-hexamethylenediamine and 4-tert~octylamino-
2,6-dichloro-1,3,5-s-triazine, tris-(2,2,6,6-tetramethyl-
piperidyl) nitrilotriacetate, tetrakis-(2,2,6,6-tetra-
methyl-4-piperidyl)-1,2,3,4-butane-tetracarbonic acid,
1,1'(1,2-ethanediyl)-bis-(3,3,5,5-tetramethylpiperazinone).
2.7. Oxalic acid diamides, for example, 4,4'-di-octyloxy-
oxanilide, 2,2'-di-octyloxy-5,5'-di-tert-butyl-oxanilide,
2,2'-di-dodecyloxy-5,5'-di-tert-butyl-oxanilide, 2-ethoxy-
2'-ethyl-oxanilide, N,N'-bis-(3-dimethylaminopropyl)-
oxalamide, 2-ethoxy-5-tert-butyl-2'-ethyloxanilide and its
mixture with 2-ethoxy-2'-ethyl-5,4'-di-tert-butyloxanilide
and mixtures of ortho- and para-methoxy-as well as of o-
and p-ethoxy disubstituted oxanilides.
3. Metal deactivators, for example, N,N'-diphenyloxalic
acid diamide, ~-salicylal-N'-salicyloylhydrazine,
N,N'-bis-salicyloylhydrazine, N,N'-bis-(3,5-di-tert-butyl-
4-hydroxyphenylpropionyl)-hydrazine, 3-salicyloylamino-
1,2,4-triazole, bis-benzylidene-oxalic acid dihydrazide.
4. Phosphites and phos~ nltes, or example, triphenyl
phosphite, diphenylalkyl phosphites, phenyldialkyl
phosphites, tri-(nonylphenyl) phosphite, trilauryl
phosphite, trioctadecyl phosphite, di-stearyl-
pentaerythrityl diphosphite, tris-(2,4-di-tert-butylphenyl)
phosphite, diisodecylpentaerythrityl diphosphite,
di-(2,4-di-tert-butylphenyl)pentaerythrityl diphosphite~
tristearyl-sorbityl triphosphite, tetrakis-
(2,4-di-tert-butylphenyl)-4,4'-diphenylylendiphosphonite.
~Z~ LO
-- 19 --
5. Compounds which destroy peroxide, for example, esters
of ~-thiodipropionic acid, for example the lauryl, stearyl,
myristyl or tridecyl esters, mercapto-benzimidazole or the
zinc salt of 2-~ercaptobenzimidazole, zinc-dibutyl-dit~o-
carbamate, dioctadecyldisulfide, pentaerythrityl-tetrakis
(~-dodecylmercapto)-propionate.
6. Polyamide stabilizers, for example copper salts in
combination with iodides and~or phosphorus compounds and
salts of divalent manganese.
7. Basic co-stabilizers, for example, melamine, polyvinyl-
pyrrolidone, dicyandiamide, triallyl cyanurate, urea
derivatives, hydrazine derivatives, amines, polyamides/
polyurethanes, alkali metal salts and alkaline earth metal
salts of higher fatty acids for example Ca stearate, 2n
stearate, Mg stearate, Na ricinoleate and K palmitate,
antimony pyrocatecholate or zinc pyrocatecholate.
8. Nucleating agents! for eample, 4-tert-butyl-benzoic
acid, adlpic acid, diphenylacetic acid.
9. Fillers and reinforcing agents, for example, calcium
carbonate, silicates, glass fibres, asbestos, talc, kaolin,
mica, barium sulfate, metal oxides and hydroxides, carbon
black, graphite.
.
10. Other additives, for example, plasticizers, lubricants,
emulsifiers, pigments, optical brighteners, flameproofing
agents, antistatic agents, blowing agents and
thiosyner~ists such as dilauryl thiodipropionate or
distearyl thiodipropionate.
lZ'i~
- 20 -
As previously noted, a number of the compounds
falling within the scope of formula I have been disclosed
in the cited publications. Other compounds are novel,
however, and thus comprise part of the instant invention.
These novel compounds correspond to those of formula I
where Rl is hydrogen, and R2 is cyclohexyl, cyclohex-3-enyl
or 3,5-di-tert-butyl-4-hydroxyphenyl. These new compounds
are, of course, prepared in the manner described
hereinabove.
The following examples further illustrate the
embodiments of this invention. In these examples, all
parts given are by weight unless otherwise specifiedO
Example 1
2,2-Bis(3,5-di-tert-butyl-4-hydroxyphenylthio)octane
A flask under a nitrogen atmosphere is charged with
a solution of 23.84 grams of
2,6-di-tert-butyl-4-mercaptophenol and 6.41 grams of
2-octanone in 150 ml of methyl alcohol. The solution is
then treated with anhydrous hydrogen chloride and held at
55C for two hours. The resulting precipitate is filtered
off and drled to give 23.75 grams (81% yield) of white
solid, mp 130-133C.
Calcd. for C36H58O2S2 C, 73-7; H~ 10. -
Found: C, 74.0; H, 9.8.
- 21 -
Example 2
1,1-Bis(3,5-di-tert-butyl-4-hydroxYphenylthio)-1-(3,5-di-
tert-butyl-4-hydroxyphenyl)methane
The procedure of Example 1 is repeated using 23.84
grams of 2,6-di-tert-butyl-4-mercaptophenol, 11.72 grams of
3,5-di-tert-butyl-4-hydroxybenzaldehyde and lS0 ml of
methyl alcohol. Trituration with methyl alcohol gives 30
grams (87% yield) of white crystals, mp 175-177C.
nal. Calcd. for C43H64O3S2 C, 74,S; ~, 9,3; S, 9.3.
Found: C, 74.5; H, 9.3; S, 9.5.
Example 3
4,4-Bis(3,5-di-tert-butyl-4-hydroxyphenylthio)-2,6,8-
trimethylnonane
The procedure of Example 1 is repeated using 9~22
grams of 2,6,8-trimethylnonan-4-one~ 23.84 grams of
2,6-di-tert-butyl-4-mercaptophenol, and 150 ml of methyl
alcohol. The product is purified by flask chromatography
to give a clear syrup whose proton NMR spectrum is
consistent with the desired structure.
.1~5~
- 22 -
Example 4
Bis~3,5-di-tert-butyl-4-hydroxyphenylthio)-2-ethy
hexane
The procedure of Example 1 is repeated using 23.84
grams or 2,6-di-tert-butyl-4-mercaptophenol, 6.41 grams of
2-ethylhexanal, and lS0 ml of methyl alcohol. The product
is purified by dry-column chromatography to give 10.29
grams of a clear syrup.
Anal. Calcd. for C3sH~gO2S2: C, 73.7; H, 10Ø
Found: C, 73.9; H, 9.9.
Example 5
1,1-Bis(3,5-di-tert-butyl-4-hydroxyphenylthio)cyclohexane
The procedure of Example 1 was repeated using 28.71
grams of 2.6-di-tert-butyl-4-mercaptophenol, 5.91 grams of
cyclohexanone, and 150 ml of methyl alcohol. The product
is triturated with methyl alcohol to give 31.17 grams
~93.3~ yield) of white solid, mp 195-197C.
nal. Calcd. for C34HS2O2S2: C~ 73-3~ H~ 9-4-
Found: C, 73.4; H, 9.5.
- 23 -
Example 6
l,l-Bis(3,5-di-tert-butyl-4-hydroxvphenylthio)-1-(cvclohex-
3-enyl)methane
A solution of 10 grams of 2,6-di-tert-butyl-4-mer-
captophenol and 2.3 grams of cyclohex-3-enyl carboxaldehyde
is charged to a flame-dried flask and treated with 1.0 ml
of tetrafluoroboric acid and stirred for two hours. The
reaction mixture is extracted with aqueous sodium
bicarbonate and dried over anhydrous magnesium sulfate.
The solvent is stripped in vacuo, and the residue
recrystallized from acetonitrile to give 9.0 grams (76%
yield) of whi~e crystals, mp 122-125C.
nal. Calcd. for C3sHs202S2: C, 73.9; H, 9.2; S, 11.3.
Found: C, 73.9; H, 9.3; S, 11.2.
Example 7
This example illustrates the stabilizing
effectiveness of the instant stabilizers in impact
polystyrene (IPS).
In the laboratory procedure utilized herein, a
solution of eight weight percent polybutadiene rubber
(Firestone-~DIENE 55) dissolved in styrene monomer is
prepared on a roller mill. The indicated amount of
stabilizer is also introduced at this point. 500 ppm of
zinc stearate is added to aid in removing the sample from
the bottle after the polymerization. The bottle is screwed
into the polymerization apparatus which is equipped with a
double helical ribbon stirrer. Since most commercial IPS
bulk polymerizations are thermally initiated processes, no
~!l 2 5 ~
- 24
initiator is used in the laboratory process. A nitrogen
atmosphere is established and the reactor is then heated to
121C within 1/2 hour. Heating continue at 121C with
efficient stirring until there is a 30 to 35% monomer
conversion (ca. 2.5 hours). The stirring rate is
controlled to yield a two to four micron rubber particle
size. The bottles are removed from the polymerization
apparatus, blanketed with nitrogen, capped, and then placed
in a fluidized bed sand bath to complete the
polymerizationO The hottles are heated in the bath in the
following fashion: one hour at 100C to equilibrate the
temperature, one hour to reach 140C and then an additional
eight hours with the temperature increasing at the rate of
10C per hour to a maximum of 220C~ After the resin is
cooled, the bottle is broken and the glass is removed. The
average weight of the polymer block is slightly over 600
grams. The block is then placed into a vacuum oven at 200C
and a vacuum of 1 mm applied as the polymer is heated for
45 minutes in order to remove all volatiles. The block is
removed from the oven, immediately placed in a heated
(205C) hydraulic press and then pressed into a thick slab
between two sheets of aluminum foil (three minutes heating,
five minutes in a cold press). The slab is split with a
band saw and the pieces are granulated.
All batches were extruded at 205C and then
pelletized. The pellets are compression molded at 205C
into 125 mil (3.175 mm) tensile bars. The bars are then
aged at 150C on glass plates placed on rotating shelves in
a forced air oven. Other tensile bars are aged at 80C
suspended from rotating shelves in a forced air oven~ The
specimen yellowness index is determined on the bars at
various intervals according to ASTM D-1925-63T.
.1 ZS L~L~3iLV
- 25 -
Correspondingly, the bars are periodically measured for
percent elongation into the Instron Tensile Testing
Apparatus (Instron Engineering Corporation, Massachusetts~
at a pull rate of 5 mm/minute according to ASTM D638.
Oven Aged Samples at 80C
~ Elongation
(Hours at 80C)
Additive Conc. 0 300 600900 1200
(~ by wt.)
None ~ 33 9
Compound of Example 1 0.1 55 24 10 9 7
Compound of Example 6 0.1 49 29 10 8 5
Yellowness _ndex
None - 7 14 45 59
Compound of Example 1 0.1 0 16 27 38 52
Compound of Example 6 0.1 2 8 19 31 43
.~ ~
1;~5~ 3~(~
- 26 -
Oven Aged Samples at 150C
~ Elongation
(Hours at 150C)
Additive ConcO 1/2 11-1/2 2
(~ by wt.)
None 33
Compound of Example 1 0.1 55 50 19 8 7
Compound of Example 6 0.1 49 36 18 10 7
Yellowness Index
None - 718 30 38 43
Compound of Example 1 0.1 0 5 7 10 15
Compound of Example 6 0.1 2 5 9 10 14
Example 8
Unstabilized polypropylene powder (Hercules~Profax
6501) is thoroughly blended with 0.2~, by weight, of
additive. The blended materials are then milled on a two
roll mill at 182C for 5 minutes, after which time the
stabilized polypropylene is sheeted from the mill and
allowed to cool.
27 -
The milled polypropylene is then cut into pieces and
compression molded on a hydraulic press at 220C at 175 psi
(12.3 Kg/cm2) into 5 mil (0.127 mm) films. The samples are
exposed to a fluorescent suinlight/black light chamber
until failure. Failure is determined as the time when the
films show the first signs of decomposition (e.g. cracking
or brown edges).
Additive Hours to Failure
None 200-300
Compound of Example 1 430
Compound oE ~xample 2 460
Compound of Example 5 480
Compound of Example 6 500
ExamDle 3
,.
The oxidation stability of milled polypropylene
containing, respectively, 0.2~, by weight, of the instant
additives as well as of a synergized formulation containing
0.1~, by weight, of the additive in the presence of 0.3~,
by weight, distearyl thiodipropionate (DSTDP) on plaques of
25 mil (0.635 mm) thickness is determined by exposing said
plaques to air in a forced draEt oven at 150C. The
plaques are considered to have failed on showing the first
signs of decomposition (e.g. cracking or brown edges).
12~
- 28 -
Time to Failure (Hrs)
Additive~Synergized Composition
Additive Conc. (~ by wt)
Compound of0.2% by wtn.l~ Additive + 0~3% DSTDP
Base Resin <20 <20
(0.3~DSTDP)
Example 1 20 80
Example 2 30 160
Example 5 20 280
Example 6 120 180
Examples 7~9 thus indicate the superior stabilizing
performance of the instant compounds in several substrates
compared to the base resin in the absence of a compound of
this invention.
Summarizing, it is seen that this invention provides
a group of compounds having superior stabilizing activity
in a variety of organic materials. Variations may be made
in proportions, procedures and materials without departing
from the scope of the invention as defined by the following
claims.
