U.S. patent application number 10/911255 was filed with the patent office on 2005-01-13 for sterically hindered phenol antioxidant granules having balanced hardness.
Invention is credited to Semen, John.
Application Number | 20050006627 10/911255 |
Document ID | / |
Family ID | 22568828 |
Filed Date | 2005-01-13 |
United States Patent
Application |
20050006627 |
Kind Code |
A1 |
Semen, John |
January 13, 2005 |
Sterically hindered phenol antioxidant granules having balanced
hardness
Abstract
Sterically hindered phenol antioxidant additive granules are
formed from a paste comprising an organic processing agent
comprising a friability reduction agent. The friability reduction
agent preferably is an alcohol, more preferably an alkanol having
up to about 8 carbon atoms, most preferably methanol, ethanol,
and/or isopranol. After drying, the granules consist essentially of
the sterically hindered phenol antioxidant additive system. The
granules have a balanced hardness that provides sufficient abrasion
resistance while permitting ready dispersion into a polymer
host.
Inventors: |
Semen, John; (Baton Rouge,
LA) |
Correspondence
Address: |
Law Department
ALBEMARLE CORPORATION
451 Florida Street
Baton Rouge
LA
70801-1765
US
|
Family ID: |
22568828 |
Appl. No.: |
10/911255 |
Filed: |
August 4, 2004 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
10911255 |
Aug 4, 2004 |
|
|
|
09528675 |
Mar 20, 2000 |
|
|
|
6800228 |
|
|
|
|
09528675 |
Mar 20, 2000 |
|
|
|
09158588 |
Sep 22, 1998 |
|
|
|
6056898 |
|
|
|
|
Current U.S.
Class: |
252/399 |
Current CPC
Class: |
C08K 5/13 20130101; B01J
2/20 20130101; C07C 69/732 20130101; C08K 5/51 20130101 |
Class at
Publication: |
252/399 |
International
Class: |
C09K 015/04 |
Claims
That is claimed is:
1. A compound comprising a powder comprising an additive system
comprising at least one sterically hindered phenol antioxidant;
and, an organic processing agent comprising at least one friability
reduction agent.
2. The compound of claim 1, wherein said friability reduction agent
is an alcohol.
3. The compound of claim 2, wherein said alcohol comprises a
composition of the formula ROH wherein R is an alkyl group of from
1 to 8 carbon atoms.
4. The compound of claim 2, wherein said alcohol is selected from
the group consisting of methanol, ethanol, isopropanol, and a
combination thereof.
5. The compound of claim 2, wherein said alcohol comprises methanol
and said organic processing agent further comprises
methylethylketone.
6. A compound consisting essentially of one or more dried granules
consisting essentially of an additive system comprising at least
one primarily crystalline sterically hindered phenol.
7. The compound of claim 6 wherein said dried granules comprise
pellets comprising a balanced hardness of at least about 5
lb/in.
8. The compound of claim 7 wherein said pellets comprise at least
about 1 wt. % of an essentially amorphous phase comprising said
sterically hindered phenol.
9. The compound of claim 7 wherein said pellets comprise from about
1 wt. % to about 5 wt. % of said essentially amorphous phase
comprising said sterically hindered phenol.
10. The compound of claim 7 wherein said balanced hardness is from
about 10 lb/in to about 27 lb/in., based on measurements made using
3 mm diameter pellets.
11. The compound of claim 9 wherein said balanced hardness is from
about 10 lb/in to about 27 lb/in., based on measurements made using
3 mm diameter pellets.
12. The compound of claim 7 wherein said balanced hardness is of
from about 15 lb/in to about 25 lb/in., based on measurements made
using 3 mm diameter pellets.
13. The compound of claim 9 wherein said balanced hardness is of
from about 15 lb/in to about 25 lb/in., based on measurements made
using 3 mm diameter pellets.
14. The compound of claim 1 wherein said at least one sterically
hindered phenol antioxidant has a melting point of from about
50.degree. C. or greater.
15. The compound of claim 6 wherein said at least one sterically
hindered phenol antioxidant has a melting point of from about
50.degree. C. or greater.
16. The compound of claim 1 wherein said at least one sterically
hindered phenol has a melting point of from about 95.degree. C. or
greater.
17. The compound of claim 2 wherein said at least one sterically
hindered phenol has a melting point of from about 95.degree. C. or
greater.
18. The compound of claim 3 wherein said sterically hindered phenol
has a melting point of from about 95.degree. C. or greater.
19. The compound of claim 4 wherein said at least one sterically
hindered phenol has a melting point of from about 95.degree. C. or
greater.
20. The compound of claim 6 wherein said at least one sterically
hindered phenol has a melting point of from about 95.degree. C. or
greater.
21. The compound of claim 7 wherein said sterically hindered phenol
has a melting point of from about 95.degree. C. or greater.
22. The compound of claim 8 wherein said at least one sterically
hindered phenol has a melting point of from about 95.degree. C. or
greater.
23. The compound of claim 9 wherein said at least one sterically
hindered phenol has a melting point of from about 95.degree. C. or
greater.
24. The compound of claim 7 wherein said pellets comprise a loose
bulk density of from about 400 g/l or greater, a Hosogawa
Flowability of about 70 or greater, an average diameter (x) of from
about 2 millimeters to about 6 millimeters, and an average length
of from about 1.5.times. to about 3.times..
25. The compound of claim 8 comprising pellets comprising a loose
bulk density of from about 400 g/l or greater, a Hosogawa
Flowability of about 70 or greater, an average diameter (x) of from
about 2 millimeters to about 6 millimeters, and an average length
of from about 1.5.times. to about 3.times..
26. The compound of claim 9 comprising pellets comprising a loose
bulk density of from about 400 g/l or greater, a Hosogawa
Flowability of about 70 or greater, an average diameter (x) of from
about 2 millimeter to about 6 millimeters, and an average length of
from about 1.5.times. to about 3.times..
27. The compound of claim 6 comprising agglomerates comprising a
loose bulk density of from about 400 g/l or greater and a Hosagawa
Flowability of about 70 or greater.
28. The compound of claim 1, wherein said sterically hindered
phenol antioxidant is selected from the group consisting of:
octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate; tetrakis
[methylene(3,5-di-t-buty- l-4-hydroxylhydrocinnamate)]methane;
1,3,5-trimethyl-2,4,6-tris-(3,5-di-t--
butyl-4-hydroxybenzyl)benzene;
1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; and
1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3-
,5-triazine-2,4,6-(1H, 3H, 5H) -trione.
29. The compound of claim 6, wherein said sterically hindered
phenol antioxidant is selected from the group consisting of:
octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate; tetrakis
[methylene(3,5-di-t-buty- l-4-hydroxylhydrocinnamate)]methane;
1,3,5-trimethyl-2,4,6-tris-(3,5-di-t--
butyl-4-hydroxybenzyl)benzene;
1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; and
1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3-
,5-triazine-2,4,6-(1H, 3H, 5H) -trione.
30. The compound of claim 1, wherein said sterically hindered
phenol antioxidant is selected from the group consisting of:
1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene;
and 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate.
31. The compound of claim 6, wherein said sterically hindered
phenol antioxidant is selected from the group consisting of:
1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene;
and 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate.
32. A compound comprising one or more dried granules made by a
process comprising: mixing an organic processing agent comprising a
friability reduction agent with a powder comprising an additive
system comprising at least a first sterically hindered phenol
antioxidant under conditions that are effective to form a paste;
processing said paste to form said one or more granules; and
exposing said one or more granules to conditions that are effective
to remove said organic processing agent from said one or more
granules but ineffective to melt said sterically hindered phenol
antioxidant.
33. The compound of claim 32 wherein said friability reduction
agent comprises an alcohol.
34. The compound of claim 33, wherein said alcohol comprises a
composition of the formula ROH wherein R is an alkyl group of from
1 to 8 carbon atoms.
35. The compound of claim 32, wherein said alcohol is selected from
the group consisting of methanol, ethanol, and isopropanol.
36. One or more granules consisting essentially of at least one
primarily crystalline sterically hindered phenol antioxidant having
a melting point of from about 50.degree. C. or greater.
37. One or more granules consisting essentially of at least one
primarily crystalline sterically hindered phenol antioxidant having
a melting point of from about 95.degree. C. or greater.
38. The granules of claim 36 comprising at least 20 wt. % of said
at least one sterically hindered phenol antioxidant.
39. The granules of claim 37 comprising at least 20 wt. % of said
at least one sterically hindered phenol antioxidant.
40. The granules of claim 36 having a balanced hardness.
41. The granules of claim 37 having a balanced hardness.
42. The granules of claim 38 having a balanced hardness.
43. The granules of claim 39 having a balanced hardness.
44. The granules of claim 42 comprising a loose bulk density of
from about 400 g/l or greater, an average diameter (x) of from
about 1 millimeters to about 10 millimeters, and, where the
granules are pellets, an aspect ratio of from about 1 to about
5.
45. The granules of claim 43 comprising a loose bulk density of
from about 400 g/l or greater, an average diameter (x) of from
about 1 millimeters to about 10 millimeters, and, where the
granules are pellets, an aspect ratio of from about 1 to about
5.
46. The granules of claim 44 wherein said length is from about 1 to
about 5 millimeters.
47. The granules of claim 45 wherein said length is from about 1 to
about 5 millimeters.
48. The granules of claim 43 wherein said sterically hindered
phenol antioxidant is selected from the group consisting of:
octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate; tetrakis
[methylene(3,5-di-t-buty- l-4-hydroxylhydrocinnamate)] methane;
1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-
-butyl-4-hydroxybenzyl)benzene;
1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl- ) isocyanurate;
1,3,5-tris-(4,4-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5--
triazine-2,4,6-(1H, 3H, 5H)-- trione; and
thiodiethylenebis-(3,5-di-t-buty- l-4-hydroxy) hydrocinnamate.
49. The granules of claim 43 wherein said sterically hindered
phenol antioxidant is selected from the group consisting of:
tetrakis [methylene(3,5-di-t-butyl-4-hydroxylhydrocinnamate)]
methane;
1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl)benzene;
1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate;
1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine-2,4,6--
(1H,3H,5H)-trione; and
thiodiethylenebis-(3,5,-di-t-butyl-4-hydroxy) hydrocinnamate.
50. The granules of claim 43 wherein said sterically hindered
phenol antioxidant is
1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl-
)benzene.
51. The granules of claim 36 wherein said at least one antioxidant
comprises from about 0 to about 80 wt. % of a secondary phosphite
antioxidant.
52. The granules of claim 37 wherein said at least one antioxidant
comprises from about 0 to about 80 wt. % of a secondary phosphite
antioxidant.
53. The granules of claim 38 wherein said at least one antioxidant
comprises from about 0 to about 80 wt. % of a secondary phosphite
antioxidant.
54. The granules of claim 39 wherein said at least one antioxidant
comprises from about 0 to about 80 wt. % of a secondary phosphite
antioxidant.
55. The granules of any of claims 42 wherein said at least one
antioxidant comprises from about 0 to about 80 wt. % of a secondary
phosphite antioxidant.
56. The granules of any of claims 43 wherein said at least one
antioxidant comprises from about 0 to about 80 wt. % of a secondary
phosphite antioxidant.
57. The granules of claim 36 wherein said additive system comprises
at least about 20 wt. % of said at least one sterically hindered
phenol antioxidant, and further comprises a material selected from
the group consisting of antistatics, antiblocking agents, flame
proofing agents, thioesters, pigments, UV absorbers, and light
stabilizers.
58. The granules of claim 37 wherein said additive system comprises
at least about 20 wt. % of said at least one sterically hindered
phenol antioxidant, and further comprises a material selected from
the group consisting of antistatics, antiblocking agents, flame
proofing agents, thioesters, pigments, UV absorbers, and light
stabilizers.
59. The granules of claim 51 wherein said additive system comprises
at least about 20 wt. % of said at least one sterically hindered
phenol antioxidant, and further comprises a material selected from
the group consisting of antistatics, antiblocking agents, flame
proofing agents, thioesters, pigments, UV absorbers, and light
stabilizers.
60. The granules of claim 52 wherein said additive system comprises
at least about 20 wt. % of said at least one sterically hindered
phenol antioxidant, and further comprises a material selected from
the group consisting of antistatics, antiblocking agents, flame
proofing agents, thioesters, pigments, UV absorbers, and light
stabilizers.
61. The granules of any of claim 59 further comprising a material
selected from the group consisting of an internal lubricant, an
external lubricant, an acid neutralizer, and a metal soap.
62. The granules of any of claim 60 further comprising a material
selected from the group consisting of an internal lubricant, an
external lubricant, an acid neutralizer, and a metal soap.
63. A compound according to claim 1 substantially as described
herein in any of the examples.
64. A compound according to claim 6 substantially as described
herein in any of the examples.
65. A process for manufacturing dried granules that are at least in
the form of agglomerates or pellets, said granules made by a
process comprising: A) mixing (i) an organic processing agent
comprising (a) a friability reduction agent or (b) an organic
solvent, or (c) both of (a) and (b) with (ii) a powder comprising
an additive system comprised of at least a first sterically
hindered phenol antioxidant, under conditions that are effective to
form a wet paste; B) processing said wet paste into at least wet
agglomerates or wet pellets without melting any solid component(s)
in the agglomerates or pellets; and C) exposing said agglomerates
or pellets to conditions that are effective to remove said organic
processing agent from said agglomerates or pellets and to dry said
agglomerates or pellets but ineffective to melt any solid component
of the agglomerates or pellets, to thereby produce dried granules
in the form of dried agglomerates or dried pellets.
66. Dried granules made according to the process of claim 65.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a Division of application Ser.
No. 09/528,675, filed Mar. 20, 2000 which is a continuation-in-part
of application Ser. No. 09/158,588, now U.S. Pat. No. 6,056,898;
application Ser. No. 09/204,121, now U.S. Pat. No. 6,126,863; and
application Ser. No. 09/203,941, now U.S. Pat. No. 6,126,862.
FIELD OF THE INVENTION
[0002] The present invention relates to the use of a paste to make
inherently coherent dried granules of sterically hindered phenol
antioxidants. The dried granules have a balanced hardness suitable
for both handling and incorporation into a polymer composition. The
granules may be agglomerates, which typically are spherical in
shape, or they may be cylindrical or elongated pellets.
BACKGROUND OF THE INVENTION
[0003] Organic polymers, in particular polyolefins such as
polyethylene and polypropylene, commonly are known as "plastics."
Various additive systems are used during the processing of plastics
in order to assure that the plastic product has long term stability
and desired service properties. Additives and stabilizers prevent
the plastic product from being damaged by light, heat, and by
residues of the catalyst system used to produce the plastic.
[0004] The additives and stabilizers may be used individually, or
in an additive "system" that includes a mixture of components.
Common additive systems include sterically hindered phenol
antioxidants in combination with a secondary phosphite antioxidant
and/or an acid neutralizer.
[0005] Sterically hindered phenol antioxidants generally are fine
powders that present dusting and other handling problems, as well
as separation tendencies that cause metering difficulties. In the
past, these problems have been solved by adding extraneous binders
to the additive system. Exemplary binders used for such purpose
include fatty acids and their salts, such as calcium stearate. The
disadvantage of using an extraneous binder is that the binder
remains as a contaminant in the final additive system.
[0006] Additive systems are needed which solve the handling
problems for sterically hindered phenols, but which do not
introduce contaminants into the final additive system.
SUMMARY OF THE INVENTION
[0007] The present invention solves the foregoing problem by
providing a compound comprising a powder comprising an additive
system comprising at least one sterically hindered phenol
antioxidant; and, an organic processing agent comprising at least
one friability reduction agent. The invention also is directed to a
compound consisting essentially of one or more dried granules
consisting essentially of an additive system comprising at least
one sterically hindered phenol.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 shows a graph of the balanced hardness for pellets
made according to the present invention as a factor of load versus
time, with the maximum attained load normalized by the length
dimension of the granule.
DETAILED DESCRIPTION OF THE INVENTION
[0009] The granules of sterically hindered phenol antioxidant of
the present invention may have any suitable form, such as
agglomerates or pellets. The granules have a "balanced hardness,"
defined as a hardness sufficient to provide adequate resistance to
abrasion during handling ("abrasion resistance") and also ready
homogeneous dispersability in a host plastic material using
conventional dispersing systems, such as a compounding extruder.
The balanced hardness is difficult to measure when the granules are
agglomerates, or spherical in shape. However, the balanced hardness
of pellets may be measured, quantified, and varied to suit
particular processing requirements.
[0010] Typically, granule coherence is achieved using an
"extraneous binder." An "extraneous binder" is defined herein as a
material that does not function as a component of the additive
system once dispersed in the host plastic, but which does assist in
achieving granule coherence and a suitable granule hardness. An
"extraneous binder" typically provides coherence to a material by
"melting" to hold the granule together after processing. Instead of
using an extraneous binder, the present invention provides
coherence and regulates balanced hardness of the granules by
regulating the composition of the "organic processing agent" used
to process the sterically hindered phenol into granules. More
specifically, the invention uses an organic processing agent which,
at least in part, comprises a friability reduction agent, most
preferably an alcohol. Preferably, the process of the present
invention is performed at a temperature that is sufficiently low to
avoid melting any component of the additive system, including the
sterically hindered phenol.
[0011] The Organic Processing Agent
[0012] The organic processing agent comprises the friability
reduction agent and also may comprise a traditional solvent. The
organic processing agent has a sufficiently low vaporization point
or boiling temperature to evaporate from the granules before the
sterically hindered phenol begins to melt or degrade. The
composition and vaporization point of the organic processing agent
thus will vary with the type and the melting point of the
sterically hindered phenol being processed.
[0013] A. The Friability Reduction Agent
[0014] The "friability reduction agent" is defined as a fluid in
which a given sterically hindered phenol has sufficient
dispersability to form a paste and to be processed into granules,
but insufficient solubility to dissolve the phenol sufficiently to
form a "glue" phase. Without limiting the invention to a particular
mechanism of action, molecules of the sterically hindered phenol
are believed to become sufficiently "dispersed" in the friability
reduction agent that, upon drying, the molecules of the sterically
hindered phenol "precipitate out" of or deposit from the friability
reduction agent, forming an essentially amorphous phase. The
majority of the sterically hindered phenol in the granules produced
according to the present invention is crystalline in nature. About
1 wt. % to about 5 wt. % of the sterically hindered phenol found in
the granules comprises an amorphous phase. The molecules of phenol
forming the amorphous phase are believed to be the precipitated
molecules of the sterically hindered phenol, which are believed to
form bonds that act as a "bridging agent" to provide inherent
coherence and "balanced hardness" to the dried granules. The
coherence is "inherent" because it is produced by components of the
additive system, itself. Coherence does not require the use of an
extraneous binder.
[0015] Suitable friability reduction agents include, but are not
necessarily limited to alcohols, preferably alkanols, most
preferably normal alkanols and their equivalents. Preferred
friability reduction agents are alcohols of the formula ROH wherein
R is an alkyl group having from about 1 to about 8 carbon atoms,
preferably from about 1 to about 4 carbon atoms. Preferred alcohols
include, but are not necessarily limited to: methanol, with a
boiling point of 148.5.degree. F. (64.7.degree. C.); ethanol, with
a boiling point of 172.5.degree. F. (78.degree. C.); and
isopropanol, with a boiling point of 179.5.degree. F. (82.degree.
C.). Isopropanol is a most preferred alcohol, and a most preferred
friability reduction agent.
[0016] B. The Solvent
[0017] As used herein, the term "solvent" is defined as an organic
solvent capable of dissolving at least about 2 g of sterically
hindered phenol per 100 mL of solvent. Examples of such "solvents"
include, but are not necessarily limited to methylene chloride,
with a boiling point of 104.degree. F. (40.degree. C.); chloroform,
with a boiling point of 142.degree. F. (61.degree. C.); toluene,
with a boiling point of 230.degree. F. (110.degree. C.); acetone
with a boiling point of 133.degree. F. (56.degree. C.); methyl
ethyl ketone, with a boiling point of 176.degree. F. (80.degree.
C.); xylene, with a boiling point of 284.degree. F. (140.degree.
C.); cyclohexane, with a boiling point of 177.degree. F.
(80.7.degree. C.); styrene, with a boiling point of 293.degree. F.
(145.degree. C.); methylcyclohexane, with a boiling point of
214.degree. F. (101.degree. C.); hexane, with a boiling point of
156.degree. F. (69.degree. C.); and combinations thereof. Most
preferred solvents are cyclohexane, methylethylketone, and
combinations thereof.
[0018] The sterically hindered phenol readily dissolves in such
solvents and produces a "glue" phase, even when the phenol is not
melted. Upon drying, this "glue phase" typically is very hard,
absent some kind of softening treatment. To the extent that the
granules contain such a solvent, the resulting "glue" phase
increases the balanced hardness of the granules. The organic
processing agent of the present invention limits the amount of the
glue phase formed during processing by controlling the amount of
"solvent" in the "organic processing agent." The solvent is
replaced by variable quantities of the "friability reduction
agent."
[0019] The Sterically Hindered Phenol
[0020] Useful sterically hindered phenol antioxidants generally
possess a characteristic melting point of from about 50.degree. C.
(122.degree. F.) or greater, preferably from about 95.degree. C.
(203.degree. F.) or greater, most preferably about 100.degree. C.
or greater. The minimum melting point provides a practical limit on
the temperature used to dry the granules. Examples of suitable
sterically hindered phenols are described below.
[0021] The amount of sterically hindered phenol antioxidant in the
granules may vary from about 5 weight percent or more, more
preferably from about 10 weight percent or more, still more
preferably from about 20 weight percent to about 50 weight percent.
The granules also may comprise 100 weight percent sterically
hindered phenol antioxidant. Other additives, i.e., active
components of the blend for the end use application are known, and
may be included in any suitable amount, with the proper amount of a
given active component of the blend being determinable by those
skilled in the art for a given use. Examples of such additives are
given below. A preferred additive is from about 15 wt. % to about
85 wt. % of an acid neutralizer. When the granules are formed in
admixture with other components, such as a phosphite antioxidant,
the agglomerates contain at least about 3 wt. %, preferably at
least about 5 wt. %, and most preferably from about 20 wt. % to
about 100 wt. % of the sterically hindered phenol.
[0022] Manufacture of Granules
[0023] For simplicity sake only, the manufacture of the granules
and various physical parameters will be discussed with reference to
alcohol as the friability reduction agent.
[0024] Formation of a Paste
[0025] The granules are made from a paste comprising a powder
comprising the sterically hindered phenol antioxidant, alone, or in
combination with desired additives, which may include another
antioxidant. The balanced hardness preferably is produced without
incorporating extraneous binders that remain in the granules after
drying; however, the friability reduction agents of the present
invention may contain one or more extraneous binders. As used
herein, the term "paste" is defined as a "slurry" with sufficient
coherence to process into granules. The paste contains at least
about 1 gram of additive powder comprising the sterically hindered
phenol antioxidant per about 100 mL of the organic processing
agent.
[0026] A suitable paste for either agglomeration or pelletization
is formed by mixing the following quantities of components in a
suitable container or hopper: from (a) about 3 parts by weight
organic processing agent to about 97 parts by weight powder, to (b)
about 20 parts by weight organic processing agent to about 80 parts
by weight powder. The mixture is agitated, e.g., with a spatula or
a paddle mixer, until a "paste" forms.
[0027] A. Formation of Agglomerates
[0028] The term "agglomerate" generally refers to a small, rounded,
or spherical body of a sterically hindered phenol antioxidant.
Where the paste is used to make agglomerates, at least about 20
weight percent of the organic processing agent must be the
friability reduction agent. This is because the friability
reduction agent acts as a wetting agent which actually initiates
agglomeration, or particle formation. The organic processing agent
used for agglomeration also may comprise up to about 80 weight
percent of the solvent.
[0029] Agglomerates typically are produced in an agglomerator, such
as a "pin agglomerator," available from Feeco International (Green
Bay, Wis.). Suitable "agglomerates" may be formed using a wide
variety of methods and agglomerating equipment well known to those
of ordinary skill in the art. Examples include, but are not
necessarily limited to those described in the following U.S.
Patents, which are incorporated herein by reference: U.S. Pat. Nos.
4,134,725; 4,902,210; 5,011,640; 5,030,400; 5,124,100; 5,460,765;
5,700,497.
[0030] To form agglomerates, the paste is placed in a container and
the container is rotated, typically at about 60 rpm, with a
rotoevaporator head. The container is simultaneously "tapped" or
tumbled, e.g., using a drum or agglomerator, in order to initiate
particle formation. A preferred agglomerator is a "pin
agglomerator," available from Feeco International (Green Bay,
Wis.). The agglomerated particles are then dried (as described
below).
[0031] B. Formation of Pellets
[0032] The paste preferably is used to form pellets. As used
herein, the term "pellet" generally refers to granules made using
extrusion techniques. Extrusion techniques typically involve the
formation of elongated "spaghetti-like" strands of extruded
material, which are broken into pieces to form pellets. As a
result, pellets typically are small, columnar or cylindrical
bodies. However, pellets may be spherical, or they may have flat
surfaces, such as those found in cubes, rectangular
parallelepipeds, etc.
[0033] Since the friability reduction agent is not required to
"initiate" pellet formation, the organic processing agent used to
form pellets may contain less than 20 weight percent of the
friability reduction agent. The paste is pressed through a die
extruder to form strands, which typically are pelletized as they
are extruded. This may be accomplished using a variety of known
methods, preferably at a maximized feed rate. Examples of pelleting
equipment suitable for adaptation and use in the present invention
include, but are not necessarily limited to those described in the
following U.S. Patents, which are incorporated herein by reference:
U.S. Pat. Nos. 4,446,086; 4,670,181; 4,902,210; 5,292,461. A
preferred pellet press is a Kahl Model 14-175 Pellet Press equipped
with a die plate containing holes of from about 2 to about 6 mm
diameter, preferably about 3 mm diameter, which runs at from about
25 lb/hr to about 150 lb/hr. The length at which the strand-like
product breaks after leaving the die is determined by a number of
factors, including but not necessarily limited to the composition,
the temperature, the extrusion pressure, the speed of the
revolutions, and the distance between the cutters and the bottom of
the die plate. The press operates at a rotor speed of nominally
from about 80 to about 250 rpm, preferably from about 80 to about
100 rpm.
[0034] Extrusion through a press preferably occurs at a temperature
below that at which solvents in the extrudant vaporize or at which
any of the components of the additive system melt. Maximum
temperatures may differ slightly for a given system, but a maximum
temperature typically is about 70.degree. C. or less. Persons of
ordinary skill in the art recognize that a variety of factors
affect the temperature of extrusion, including but not necessarily
limited to powder composition, rotor speed, feed rate, solvent,
type of pellet mill, etc. However, the "aspect ratio," or the ratio
of the diameter to the length of the holes in the die plate, is of
particular importance. The smaller the "aspect ratio," the cooler
the temperature of extrusion. Typically, an aspect ratio of from
about 2.5 to about 4 is required to maintain the extrudation
process at a temperature of about 70.degree. C. or less.
[0035] Drying
[0036] After formulation, the agglomerates or pellets ("formed
granules") are dried. "Drying" of the formed granules involves
exposing the formed granules to elevated temperatures which are
sufficiently high to evaporate the organic processing agent(s) but
sufficiently low to avoid melting of the components in the additive
system, including the sterically hindered phenol. The drying
temperature may vary depending upon a number of factors,
particularly the type of phenol, the other additives found in the
granules, and the processing solvent used. Typically, the formed
granules are dried for a period of from about 30 minutes to about 6
hours, preferably for about 60 minutes in a forced-air oven
operating under an inert atmosphere--preferably nitrogen--at a
temperature of from about 50.degree. C. to the melting temperature
of the lowest melting additive in the granule, preferably at about
100.degree. C. or less. A vacuum, or partial pressure, also may be
used to facilitate drying. A "dried granule" is defined as a
granule that has been subjected to sufficient drying to remove the
organic processing agent to about 0.1 weight percent or less,
depending upon commercial specifications for the dried product.
[0037] The dried granules are sieved using an appropriately sized
screen to remove fines. Dried agglomerates typically have an
average diameter of from about 1 mm to about 10 mm, preferably from
about 1 mm to about 5 mm. Dried pellets have (a) an average
diameter (x) of from about 1 mm to about 10 mm, preferably from
about 2 mm to about 6 mm, most preferably about 3 mm, and (b) an
average length of from about 1.5.times. to about 3.times.,
typically and perhaps preferably 2.times. to 3.times.. Whether
agglomerates or pellets, the granules generally possess a loose
bulk density of from about 400 g/l or greater, with a preferred
loose bulk density being from about 500 g/l or greater.
[0038] Hosokawa Flowability
[0039] For ease of addition to a host plastic, the granules
preferably have a high "Hosokawa Flowability" rating. Hosokawa
Flowability is a powder flowability rating based on a 1-100 rating
scale, with 100 representing ideally perfect powder flow and 0
representing extremely poor powder flow. Hosokawa Flowability of
the pellets made according to the present invention preferably is
about 70 or greater, more preferably about 80 or greater.
[0040] Control Over Balanced Hardness
[0041] The balanced hardness of both agglomerates and pellets is
affected by the quantity of the friability reduction agent used.
However, the impact of the friability reduction agent on the
balanced hardness of the pellets is measurable. Balanced hardness
of pellets is calculated as a factor of load versus time, as seen
in FIG. 1, with the maximum attained load normalized by the length
dimension of the granule being the balanced hardness for a given
composition. As seen in FIG. 1, the x-axis is delineated as a
measure of displacement (inches), with the y-axis metered in pounds
(lb).
[0042] An inverse relationship exists between the balanced hardness
of pellets formed using the paste and the quantity of the
friability reduction agent used in the organic processing agent. As
the concentration of alcohol in the organic processing agent
increases, the balanced hardness of the pellets decreases. As the
concentration of the alcohol in the organic processing agent
decreases, the balanced hardness of the pellets increases. The use
of organic processing agents comprising less friability reduction
agent creates pellets having maximum hardness and a maximum
balanced hardness for a given sterically hindered phenol
antioxidant system. The use of organic processing agents comprising
only the friability reduction agent creates pellets having maximum
softness and a minimum balanced hardness for a given sterically
hindered phenol antioxidant system. The organic processing agent
controls the balanced hardness even though the organic processing
agent eventually is removed from the pellets, typically by
drying.
[0043] Minimal balanced hardness for the dried pellets comprises
from about 5 lb/in or greater. A preferred balanced hardness for
pellets is from about 10 lb/in to about 27 lb/in, more preferably
from about 15 lb/in to about 25 lb/in. In most polymer processing
procedures, a balanced hardness of from at least about 10 lb/in and
no greater than about 27 lb/in is desired for convenient handling
and ready dispersion in the polymer forming, hot plastic, process.
However as handling norms of a particular polymer processing
procedure become milder, the minimum useful balanced hardness for
the pellets may be as low as about 5 lb/in. Pellets possessing
minimum hardness of from about 5 lb/in or greater generally retain
adequate mechanical strength or hardness to have sufficient
abrasion resistance to preclude dust formation during conveyance
into the polymer forming process. The maximum hardness or
friability limit of the dried pellets permits the additive package
to readily disperse into a given host plastic process, such as
processes that require a hardness of from about 27 lb/in or less.
The combination of the minimum and maximum hardness over a given
operable range comprises the balanced hardness of the sterically
hindered phenol antioxidant pellets for limits of a given host
plastic process.
[0044] Because the balanced hardness of dried pellets bears a
relation to the concentration of alcohol in the organic processing
agent, pellets may be produced having a specific, targeted balanced
hardness. In order to produce pellets having a balanced hardness of
from about 10 lb/in to about 27 lb/in, the organic processing agent
comprises from about 20 weight percent to about 50 weight percent
alcohol. The remainder of the organic processing agent, from about
50 weight percent to about 80 weight percent, is solvent. The
balanced hardness may be refined by adjusting the alcohol content
during processing. The organic processing agent controls the
balanced hardness even though the organic processing agent
eventually is removed from the pellets, typically by drying.
[0045] As the hardness of the granules increases, it is more
difficult and requires more energy to uniformly disperse the
additive package found in the granules into the host plastic during
extrusion. As more energy is needed, and particularly when the
granule hardness is extremely high, specially designed extruders
may be required to extrude the host plastic in order to allow an
extended resonance time of the additive package in the extruders,
or to allow for the use of higher than normal temperatures. In
general, as the granule hardness goes up, the ability of the
additive package to disperse in the plastic host goes down. The
upper limit of the balanced hardness may be varied to fit
particular processing needs.
EXAMPLES OF COMPONENTS OF THE ADDITIVE SYSTEM
[0046] Representative sterically hindered phenol antioxidants
suitable for use in the present invention include organic materials
useful in the stabilization of polymers such as polyethylene and
polypropylene, and preferably comprise the formula (I): 1
[0047] wherein a R.sub.1 and R.sub.2 independently are selected
from the group consisting of substituents which provide sufficient
bulk to prevent conversion of the --OH to an oxygen radical. In a
preferred embodiment, R.sub.1 and R.sub.2 independently are
selected from the group consisting of alkyl groups and
alkylthioalkyl groups, and R.sub.3, R.sub.4 and R.sub.5
independently are selected from the group consisting of hydrogen,
alkyl groups, aromatic groups, and heterocyclic groups comprising
compounds selected from the group consisting of nitrogen, oxygen,
phosphorous and sulphur. In a preferred embodiment, R.sub.1 and
R.sub.2 independently are selected from the group consisting of
hydrogen, methyl groups, ethyl groups and tert-butyl groups, and
R.sub.4 and R.sub.5 are hydrogens. Even more preferably, R.sub.1
and R.sub.2 independently are selected from the group consisting of
methyl groups and tert-butyl groups.
[0048] Numerous types of sterically hindered phenol antioxidants
may be used in the present invention, including but not necessarily
limited to antioxidants comprising alkylated monophenols,
alkylthiomethylphenols, hydroquinones, alkylated hydroquinones,
tocopherols, hydroxylated thiodiphenyl ethers, alkylidene
bisphenols, O--, N--, and S-benzyl compounds, hydroxybenzylated
malonates, hydroxybenzyl aromatics, triazines, benzylphosphonates,
acylaminophenols, esters of
.beta.-(5-tert-butyl-4-hydroxy-3-methylphenyl) propionic acid,
esters of .beta.-(3,5-dicyclohexyl-4-hydroxyphenyl) propionic acid,
esters of 3,5-di-tert-butyl-4-hydroxyphenylacetic acid, amides of
.beta.-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid, and
combinations thereof.
[0049] Examples of these classes of sterically hindered phenol
antioxidants include, but are not necessarily limited to the
following:
[0050] Alkylated monophenols: 2,6-di-tert-butyl-4-methylphenol,
2-butyl-4,6-dimethylphenol, 2,6-di-tert-buty 1-4-ethylphenol,
2,6-di-tert-butyl-4-n-butylphenol,
2,6-di-tert-butyl-4-isobutylphenol,
2,6-dicyclopentyl-4-methylphenol,
2-(.alpha.-methylcyclohexyl)-4,6-dimeth- ylphenol,
2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,
2,6-di-tert-butyl-4-methoxymethylphenol,
2,6-dinonyl-4-methylphenol, 2,4-dimethyl
-6-(1'-methyl-undec-1'-yl)-phenol, 2,4-dimethyl-6-(1'-methyl-
heptadec-1'-yl)phenol,
2,4-dimethyl-6-(1'-methyltridec-1'-yl)phenol, and mixtures thereof;
Alkylthiomethylphenols: 2,4-dioctylthiomethyl-6-tert-bu- tylphenol,
2,4-dioctylthiomethyl -6-methylphenol, 2,4-dioctylthiomethyl-6--
ethylphenol, 2,6-didodecylthiomethyl -4-nonylphenol;
[0051] Hydroquinones and alkylated hydroquinones:
2,6-di-tert-butyl-4-meth- oxyphenol, 2,5-di-tert-butylhydroquinone,
2,5-di-tert-amylhydroquinone, 2,6-diphenyl -4-octadecyloxyphenol,
2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,
3,5-di-tert-butyl-4-hydroxyanisole,
3,5-di-tert-butyl-4-hydroxyphenyl stearate, bis
(3,5-di-tert-butyl-4-hydr- oxyphenyl) adipate.
[0052] Hydroxylated thiodiphenyl ethers:
2,2'-thiobis(6-tert-butyl-4-methy- lphenol),
2,2'-thiobis(4-octylphenol), 4,4'-thiobis(6-tert-butyl-3-methylp-
henol), 4,4'-thiobis (6-tert-butyl-2-methylphenol), 4,4'-thiobis
(3,6-di-sec-amylphenol), 4,4'-bis (2,6-dimethyl -4-hydroxyphenyl)
disulfide.
[0053] Alkylidene bisphenols:
2,2'-methylenebis(6-tert-butyl-4-methylpheno- l), 2,2'-methylenebis
(6-tert-butyl-4-ethylphenol), 2,2'-methylenebis [4-methyl
-6-(.alpha.-methylcyclohexyl)phenol], 2,2'-methylenebis
(4-methyl-6-cyclohexylphenol), 2,2'-methylene-bis
(6-nonyl-4-methylphenol- ), 2,2'-methylenebis
(4,6-di-tert-butylphenol), 2,2'-ethylidenebis
(4,6-di-tert-butylphenol), 2,2'-ethylidenebis (6-tert-butyl
-4-isobutylphenol), 2,2'-methylenebis
[6-(.alpha.-methylbenzyl)-4-nonylph- enol], 2,2'-methylenebis
[6-(.alpha.,.alpha.-dimethylbenzyl)-4-nonylphenol- ],
4,4'-methylenebis (2,6-di-tert-butylphenol), 4,4'-methylenebis
(6-tert-butyl-2-methylphenol), 1,1-bis (5-tert-butyl
-4-hydroxy-2-methylphenyl)butane, 2,6-bis
(3-tert-butyl-5-methyl-2-hydrox- ybenzyl)-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-dodecylmerca-
ptobutane, ethylene glycol bis [3,3-bis
(3'-tert-butyl-4'-hydroxyphenyl) butyrate], bis
(3-tert-butyl-4-hydroxy -5-methylphenyl)dicyclopentadiene, bis
[2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)
-6-tert-butyl-4-methylp- henyl]terephthalate, 1,1-bis
(3,5-dimethyl-2-hydroxyphenyl) butane, 2,2-bis
(3,5-di-tert-butyl-4-hydroxyphenyl)propane, 2,2-bis (5-tert-butyl
-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane,
1,1,5,5-tetr.alpha.-(5-tert-butyl-4-hyd
roxy-2-methylphenyl)pentane.
[0054] O-, N- and S-benzyl compounds:
3,5,3',5'-tetra-tert-butyl-4,4'-dihy- droxydibenzyl ether,
octadecyl 4-hydroxy-3,5-dimethylbenzylmercaptoacetate- , tris
(3,5-di-tert-butyl -4-hydroxybenzyl)amine, bis
(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) dithioterephthalate,
bis (3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, isooctyl
3,5-di-tert-butyl 4-hydroxybenzylmercapto-cetate.
[0055] Hydroxybenzylated malonates: dioctadecyl 2,2-bis
3,5-di-tert-butyl 2-hydroxybenzyl)malonate, dioctadecyl
2-(3-tert-butyl-4-hydroxy -5-methylbenzyl)malonate,
didodecylmercaptoethyl 2,2-bis (3,5-di-tert-butyl
-4-hydroxybenzyl)malonate, di-[4-(1,1,3,3-tetramethylb-
utyl)phenyl]-2,2-bis(3,5-di-tert-butyl
-4-hydroxybenzyl)malonate.
[0056] Hydroxybenzyl aromatic compounds: 1,3,5-tris
(3,5-di-tert-butyl-4-hydroxybenzyl) -2,4,6-trimethylbenzene,
1,4-bis (3,5-di-tert-butyl-4-hydroxybenzyl)
-2,3,5,6-tetramethylbenzene,
2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.
[0057] Triazine compounds:
2,4-bisoctylmercapto-6-(3,5-di-tert-butyl-4-hyd- roxyanilino)
-1,3,5-triazine, 2-octylmercapto-4,6-bis
(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,
2-octylmercapto-4,6-bis
(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazi- ne, 2,4,6-tris
(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine, 1,3,5-tris
(3,5-di-tert-butyl -4-hydroxybenzyl)isocyanurate,
1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)-isocyanurate,
2,4,6-tris (3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,
1,3,5-tris
(3,5-di-tert-butyl-4-hydroxyphenyl-propionyl)hexahydro-1,3,5-t-
riazine, 1,3,5-tris
(3,5-dicyclohexyl-4-hydroxybenzyl)isocyanurate.
[0058] Benzylphosphonates: dimethyl
2,5-di-tert-butyl-4-hydroxybenzylphosp- honate; diethyl
3,5-di-tert-butyl-4-hydroxybenzylphosphonate;
dioctadecyl-3,5-di-tert-butyl -4-hydroxybenzylphosphonate;
dioctadecyl 5-tert-butyl-4-hydroxy-3-methylbenzyl-phosphonate,
calcium salt of monoethyl 3,5-di-tert-butyl-4-hydroxybenzyl
phosphonate.
[0059] Acylaminophenols: 4-hydroxylauranilide;
4-hydroxystearanilide; octyl
N-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.
[0060] Esters of
.alpha.-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid, with
monohydric or polyhydric alcohols, such as methanol, ethanol,
octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene
glycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol,
diethylene glycol, triethylene glycol, pentaerythritol,
tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxyethyl)oxalamide,
3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,
trimethylolpropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo
-[2.2.2]octane.
[0061] Amides of
.beta.-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid: 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.
[0062] Exemplary sterically hindered phenol antioxidant compounds
include: 2
[0063] 2,6-di-t-butyl-N,N-dimethylamino-p-cresol, which has a
melting point of 94.degree. C. (201.degree. F.) and is a product of
Albemarle Corporation of Richmond, Va., and available under the
trade name Ethanox.RTM. 703 antioxidant; 3
[0064] 4,4'-methylenebis(2,6-di-t-butylphenol), which has a melting
point of 154.degree. C. (309.degree. F.) and is a product of
Albemarle Corporation of Richmond, Va., and available under the
trade name Ethanox.RTM. 702 antioxidant; 4
[0065]
2-tert-butyl-6-(3-tert-butyl-2-hydroxy-5-methylbenzyl)-4-methylphen-
yl acrylate, which has a melting point of 128-132.degree. C.
(262-270.degree. F.) and is commercially available from Ciba
Specialty Chemicals as Irganox 3052; 5
[0066]
2,4-bis(n-octylthio)-6-(4-hydroxy-3,5-di-t-butylanilino)-1,3,5-tria-
zine, which has a melting point of 390-407.degree. C.
(199-208.5.degree. F.) and is a product of Ciba Special Chemicals
of Tarrytown, N.Y., and available under the trade name Irganox 565;
6
[0067] 1,6-hexanediyl
3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropanoate- , which has a
melting point of 93-108.degree. C. (199-227.degree. F.) and is
commercially available from Ciba Specialty Chemicals as Irganox
259; 7
[0068] 1,2-ethanediylbis(oxy-2,1-ethanediyl)
3-(1,1-dimethylethyl)-4-hydro- xy-5-methyl-phenylpropanoate, which
has a melting point of 76-79.degree. C. (168-175.degree. F.) and is
commercially available from Ciba Specialty Chemicals as Irganox
245; 8
[0069] 2-methyl-4,6-di[(octylthio)methyl]phenol, which is a liquid
at ambient temperatures, and is commercially available from Ciba
Specialty Chemicals as Irganox 1520; 9
[0070] 2,2'-ethylidenebis(4,6-di-tert-butylphenol), which has a
melting point of from about 161-163.degree. C. (321-326.degree. F.)
and is commercially available from Ciba Specialty Chemicals as
Irganox 129;
[0071] Preferred sterically hindered phenol antioxidants
include:
[0072] Octadecyl 3,5-di-t-butyl-4-hydroxyhydrocinnamate having the
structure: (X) 10
[0073] which has a melting point of 50-55.degree. C.
(122-131.degree. F.) and is a product of Ciba Special Chemicals of
Tarrytown, N.Y., and available under the trade name Irganox
1076;
[0074] Tetrakis
[methylene(3,5-di-t-butyl-4-hydroxylhydrocinnamate)]methan- e
having the structure: 11
[0075] which has a melting point of 110-125.degree. C.
(230-257.degree. F.) and is a product of Great Lakes Chemical
Corporation of West Lafayette, Ind., or Ciba Specialty Chemicals of
Tarrytown, N.Y., and available under the trade name Anox 20 or
Irganox 1010, respectively;
[0076] 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate
having the structure: 12
[0077] which has a melting point of 218-224.degree. C.
(424.5-433.5.degree. F.) and is a product of Albemarle Corporation
of Richmond, Va., and available under the trade name Ethanox.RTM.
314 antioxidant or Ciba Specialty Chemicals of Tarrytown, N.Y., and
available under the trade name Irganox 3114;
[0078]
1,3,5-tris-(4-t-butyl-3-hydroxy-2,6-dimethylbenzyl)-1,3,5-triazine--
2,4,6-(1H, 3H, 5H)-trione having the structure: 13
[0079] which has a melting point of 155-159.degree. C.
(311-318.degree. F.) and is a product of Cytec of Stamford, Conn.,
and available under the trade name Cyanox 1790;
[0080] Thiodiethylenebis-(3,5-di-t-butyl-4-hydroxy) hydrocinnamate
having the structure: 14
[0081] which is a product of Ciba Speciality Chemicals of
Tarrytown, N.Y., which has a melting point of about 63.degree. C.
(145.degree. F.), and is available under the trade name Irganox
1035; and,
[0082]
1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxybenzyl)
benzene having the structure: (XVI) 15
[0083] which has a melting point of 244.degree. C. (471.degree. F.)
and is a product of Albemarle Corporation of Richmond, Va., and
available under the trademark Ethanox.RTM. 330 antioxidant.
[0084] Of these preferred sterically hindered phenol antioxidants,
1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)
benzene and 1,3,5-tris-(3,5-di-t-butyl-4-hydroxybenzyl)
isocyanurate are most preferred.
[0085] In addition to the sterically hindered phenol antioxidant of
the present invention, the stabilizer granules also may comprise a
"secondary phosphite antioxidant," so designated because the
phosphite antioxidant is always included with at least a "first"
sterically hindered phenol antioxidant. Suitable secondary
phosphite antioxidants are known in the art, and the proper type
and amount of secondary phosphite antioxidant can be determined
without undue experimentation by those of ordinary skill in the
art. A suitable amount of secondary phosphite antioxidant will vary
with the intended use of the additive system, typically from about
0 weight percent to about 80 weight percent, preferably from about
3 weight percent to about 70 weight percent. The weight ratio
between the sterically hindered phenol antioxidant and the
secondary phosphite antioxidant, where used, preferably ranges from
about 20:1 to about 1:10, with a more preferred range of from about
10:1 to about 1:5, and a most preferred range of from about 2:1 to
about 1:4.
[0086] Exemplary secondary phosphite antioxidants include, without
limitation, such compounds as phosphites, phosphonites,
fluoro-phosphonites and similar phosphite antioxidant compounds
useful in stabilizing plastics. Examples include, but are not
necessarily limited to organic phosphites and phosphonites,
particularly in stabilizing polyolefin polymer compositions. These
include aromatic phosphites and phosphonites, for example triphenyl
phosphite, diphenyl alkyl phosphites, phenyl dialkyl phosphites,
tris(diphenyl alkyl phosphite)amines, tris(nonylphenyl) phosphite,
trilauryl phosphite, trioctadecyl phosphite, distearyl
pentaerythrityl diphosphite, tris(2,4-di-tert-butylphenyl)
phosphite, distearyl pentaerythrityl diphosphite,
bis(2,4-di-tert-butylph- enyl) pentaerythrityl diphosphite,
tristearyl sorbityl triphosphite,
tetrakis(2,4-di-tert-butylphenyl)-4,4'-biphenylene diphosphonite,
3,9-bis(2,4-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosph-
a spiro[5.5]undecane,
3,9-tris(2,4,6-tris-tert-butylphenoxy)-2,4,8,10-tetr-
aoxa-3,9-diphosphaspiro[5,5]undecane and
2,2'-ethylidenebis(4,6-di-tert-bu- tylphenyl) fluorophosphite.
[0087] Particularly useful phosphites include: 16
[0088] 2,2'-ethylidenebis-(4,6-di-t-butylphenyl)-fluorophosphonite,
which has a melting point of 201.degree. C. (393.degree. F.) and is
a product of Albemarle Corporation of Richmond, Va., and available
under the trademark Ethanox.RTM.398 antioxidant; 17
[0089] bis(2,4-di-t-butylphenyl)pentaerythritol-di-phosphite, which
has a melting point of 160-175.degree. C. (320-347.degree. F.) and
is a product of GE Specialty Chemicals of Parkersburg, West Va.,
and available under the trade name Ultranox 626; 18
[0090] tris(2,4-di-tert-butylphenyl) phosphite, which has a melting
point of 680-700.degree. C. (360.5-370.5.degree. F.) and is a
product of Ciba Special Chemicals of Tarrytown, N.Y., and available
under the trade name Irgafos 168; 19
[0091]
2,2',2"-nitrilo[triethyl-tris[3,3',5,5'-tetra-t-butyl-1,1'-biphenyl-
-2,2'-diyl] phosphite, which has a melting point of 200-754.degree.
C. (392-401.degree. F.) and is a product of Ciba Special Chemicals
of Tarrytown, N.Y., and available under the trade name Irgafos 12;
20
[0092] tetrakis
(2,4-di-t-butylphenyl)-4,4'-biphenylenediphosphonite, which has a
melting point of 85-95.degree. C. (185-203.degree. F.) and is a
product of Clariant of Frankfurt, Germany, and available under the
trade name Sandostab P-EPQ. 21
[0093] bis[2,4-dicumylphenyl]pentaerythritol diphosphite, which has
a melting point of 225.degree. C. (437.degree. F.) or greater and
is a product of Dover Chemical Corp., Dover Ohio, a subsidiary of
ICC Industries, available under the name DOVERPHOS S-9228.
[0094] Preferred combinations of the sterically hindered phenol
antioxidant and the secondary phosphite antioxidant include the
combination of
1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxyben- zyl)
benzene and tris(2,4-di-tert-butylphenyl) phosphite.
[0095] The additive system of the present invention optionally may
include one or more additive selected from the group consisting of
plastic additives of metal soaps, antistatics, antiblocking agents,
flame proofing agents, thioesters, internal lubricants, pigments,
UV absorbers, light stabilizers, plasticizers, emulsifiers, optical
brighteners, and/or blowing agents.
[0096] A preferred additive comprises acid neutralizers. Suitable
acid neutralizers include, but are not necessarily limited to metal
oxides, metal carbonates, hydrotalcites, and similar compounds
useful in achieving acid neutralization in an additive system. The
acid neutralizers may be naturally occurring minerals or synthetic
compounds. Where used, an acid neutralizer typically comprises from
about 0 weight percent to about 80 weight percent, preferably from
about 20 weight percent to about 60 weight percent of the additive
system. A preferred acid neutralizer comprises a hydrotalcite.
[0097] Suitable hydrotalcites for the present invention include
those represented by the general formula:
M.sup.2+.sub.1-xM.sup.3+.sub.x(OH).sub.2(A.sup.n-).sub.x/nmH.sub.2O
[0098] wherein M.sup.2+ is selected from the group consisting of
Mg.sup.2+, Ca.sup.2+, Sr.sup.2+, Ba.sup.2+, Zn.sup.2+, Cd.sup.2+,
Pb.sup.2+, Sn.sup.2+, or Ni.sup.2+; M.sup.3+.dbd.Al.sup.3+,
B.sup.3+ or Bi.sup.3+; A.sup.n- is an anion having a valence of n,
preferably selected from the group consisting of OH.sup.-,
Cl.sup.-, Br.sup.-, I.sup.-, ClO.sub.4.sup.-, HCO.sub.3.sup.-,
CH.sub.3COO.sup.-. C.sub.6H.sub.5COO.sup.-, CO.sub.3.sup.2-,
SO.sub.4.sup.2-, (COO.sup.-).sub.2,
(CHOH).sub.4CH.sub.2OHCOO.sup.-. C.sub.2H.sub.4(COO).sub.2.sup.2-,
(CH.sub.2COO.sub.2.sup.2-, CH.sub.3CHOHCO, SiO.sub.3.sup.2-,
SiO.sub.4.sup.4-, Fe(CN).sub.6.sup.3-, Fe(CN).sub.6.sup.4- or
HPO.sub.4.sup.2-; n is from about 1 to about 4; x is from about 0
to about 0.5; and m is from about 0 to about 2. Preferably,
M.sup.2+ is Mg.sup.2+ or a solid solution of Mg and Zn, M.sup.3+ is
Al.sup.3+; A.sup.n- is CO.sub.3.sup.2-, x is a number from 0 to
0.5, and m is a number from 0 to 2.
[0099] Exemplary hydrotalcites include, but are not necessarily
limited to: Al.sub.2O.sub.3.6MgO.CO.sub.2.12H.sub.2O;
Mg.sub.4.5Al.sub.2(OH).sub.- 13.CO.sub.3.3,5H.sub.2O;
4MgO.Al.sub.2O..sub.3CO.sub.2.9H.sub.2O;
4MgO.Al.sub.2O.sub.3.CO.sub.26H.sub.2O;
ZnO.3MgO.Al.sub.2O.sub.3.CO.sub.2- .8-9H.sub.2O and
ZnO.3MgO.Al.sub.2O.sub.3.CO.sub.2.5-6H.sub.2O. The amount of
hydrotalcite incorporated into the granules varies according to the
intended use of the granules, and preferably is from about 0 weight
percent to about 50 weight percent, more preferably from about 3
weight percent to about 40 weight percent hydrotalcite.
Hydrotalcites are commercially available from Kyowa Chemical
Company of Japan under the trademark DHT-4A, DHT-4C and DHT-4V.
[0100] Preferred metal oxides include divalent metal oxides,
particularly Group II metal oxides, most preferably zinc oxide and
magnesium oxide. The amount of metal oxide used in the granules
will vary with the intended use of the granules, preferably from
about 0 weight percent to about 90 weight percent, more preferably
from about 5 weight percent to about 60 weight percent, and most
preferably from about 40 weight percent to about 50 weight percent.
Preferred metal carbonates include, but are not necessarily limited
to divalent metal carbonates, preferably Group II metal oxides,
most preferably calcium carbonate. The amount of metal carbonate
used in the granules will vary with the intended use of the
granules, preferably from about 0 weight percent to about 90 weight
percent, more preferably from about 5 weight percent to about 60
weight percent.
[0101] Other suitable additives for use in the additive system
include, but are not necessarily limited to Group II fatty acid
metal salts (metal soaps) and similar compounds, such as magnesium,
tin, zinc or preferably calcium salts having, for example,
aliphatic saturated C.sub.2-C.sub.22 carboxylates, aliphatic
olefinic C.sub.3-C.sub.22 carboxylates, aliphatic C.sub.2-C.sub.22
carboxylates substituted by at least one OH group, cyclic or
bicyclic C.sub.5-C.sub.22 carboxylates, aromatic C.sub.7-C.sub.22
carboxylates, aromatic C.sub.7-C.sub.22 carboxylates substituted by
at least one OH group, C.sub.1-C.sub.16 alkyl-substituted
phenylcarboxylates and phenyl-C.sub.1-C.sub.16 alkylcarboxylates,
preferably stearates, laurates and behenates. Other preferred metal
soaps include, but are not necessarily limited to calcium stearate,
zinc stearate, and magnesium stearate. The amount of metal soap
used in the granules will vary with the intended use of the
granules, preferably from about 0 weight percent to about 90 weight
percent, and more preferably from about 5 weight percent to about
60 weight percent.
[0102] Preferred thioesters include, but are not necessarily
limited to esters of P-thiodipropionic acid, for example the
lauryl, stearyl, myristyl or tridecyl esters,
mercaptobenzimidazole, the zinc salt of 2-mercaptobenzimidazole,
zinc dibutyldithiocarbamate, dioctadecyl disulfide, pentaerythritol
tetrakis(.beta.-dodecylmercapto)propionate or ethylene glycol
bismercaptoacetate. Suitable lubricants include, but are not
necessarily limited to montan wax, fatty acid esters, polyethylene
waxes, amide waxes, chlorinated paraffins, glycerol esters,
alkaline earth metal soaps and other similar lubricants. Additives
also may include UV absorbers and light stabilizers such as
2-(2'-hydroxyphenyl)benzotriazoles, for example
2-(2'-hydroxy-5'-methylph- enyl)benzotriazole,
2-(3',5'-di-tert-butyl-2'-ydroxyphenyl)benzotriazole,
2-(5'-tert-butyl-2'-hydroxyphenyl)benzotriazole, 2-(2'-hydroxy
-5'-(1,1,3,3-tetramethylbutyl) phenyl)benzotriazole,
2-(3',5'-di-tert-butyl-2'-hydroxyphenyl) -5-chlorobenzotriazole,
2-(3'-tert-butyl-2'-hydroxy-5'-methylphenyl)-5-chlorobenzotriazole,
2-(3'-sec-butyl-5'-tert-butyl-2'-hydroxyphenyl)benzotriazole,
2-(2'-hydroxy -4'-octoxyphenyl)benzotriazole,
2-(3',5'-di-tert-amyl-2'-hy- droxyphenyl)benzotriazole,
2-(3',5'-bis(.alpha.,.alpha.-dimethylbenzyl)-2'-
-hydroxyphenyl)benzotriazole, mixture of
2-(3'-tert-butyl-2'-hydroxy-5'-(2-
-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,
2-(3'-tert-butyl-5'
[2-(2-ethylhexyloxy)carbonylethyl]-2'-hydroxyphenyl)
-5-chlorobenzotriazole,
2-(3'-tert-butyl-2'-hydroxy-5'-(2-methoxycarbonyl- ethyl)phenyl)
-5-chlorobenzotriazole, 2-(3'-tert-butyl-2'-hydroxy-5'-(2-me-
thoxycarbonylethyl)phenyl) benzotriazole,
2-(3'-tert-butyl-2'-hydroxy-5'-(- 2-octyloxycarbonylethyl)phenyl)
benzotriazole, 2-(3'-tert-butyl-5'-[2-(2-e-
thylhexyloxy)carbonylethyl]-2'-hydroxyphenyl)benzotriazole
2-(3'-dodecyl-2'-hydroxy-5'-methylphenyl) benzotriazole, and
2-(3'-tert-butyl-2'-hydroxy -5'-(2-isooctyloxycarbonylethyl)
phenylbenzotriazole,
2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6-ben-
zotriazol-2-yl phenol]; transesterification product of
2-[3'-tert-butyl-5'-(2-methoxycarbonylethyl)-2'-hydroxyphenyl]benzotriazo-
le with polyethylene glycol 300;
[R--CH.sub.2CH.sub.2--COO(CH.sub.2).sub.3- ].sub.2 where R is
3'-tert-butyl-4'-hydroxy-5'-2H-benzotriazol-2-yl phenyl.
[0103] Hydroxybenzophenones, including but not necessarily limited
to the 4-hydroxy, 4-methoxy, 4-octoxy, 4-decyloxy, 4-dodecyloxy,
4-benzyloxy, 4,2',4'-trihydroxy and 2'-hydroxy-4,4'-dimethoxy
derivatives. Esters of unsubstituted or substituted benzoic acids,
for example 4-tert-butyl-phenyl salicylate, phenyl salicylate,
octylphenyl salicylate, dibenzoylresorcinol,
bis(4-tert-butylbenzoyl)resorcinol, benzoylresorcinol,
2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxyben- zoate,
hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl
3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl
-4,6-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate.
Acrylates, including but not necessarily limited to ethyl and
isooctyl .alpha.-cyano-.beta.,.beta.-dip- henylacrylate, methyl
.alpha.-carbomethoxycinnamate, methyl and butyl
.alpha.-cyano-.beta.-methyl-p-methoxycinnamate, methyl
.alpha.-carbomethoxy-p-methoxycinnamate and
N-(.beta.-carbomethoxy-.beta.- -cyanovinyl)-2-methylindoline.
[0104] Nickel compounds, including but not necessarily limited to
nickel complexes of 2,2'-thiobis
[4-(1,1,3,3-tetramethylbutyl)phenol], such as the 1:1 and 1:2
complexes, if desired with additional ligands, such as
n-butylamine, triethanolamine or N-cyclohexyldiethanolamine, nickel
dibutyldithiocarbamate, nickel salts of monoalkyl esters, such as
the methyl or ethyl esters, of
4-hydroxy-3,5-di-tert-butylbenzylphosphonic acid, nickel complexes
of ketoximes, such as of 2-hydroxy-4-methylphenyl undecyl ketoxime,
and nickel complexes of 1-phenyl-4-lauroyl-5-hydroxypyr- azole, if
desired with additional ligands. Oxalamides, including but not
necessarily limited to 4,4'-dioctyloxyoxanilide,
2,2'diethoxyoxanilide, 2,2'-dioctyloxy-5,5'-di-tert-butyloxanilide,
2,2'-didodecyloxy-5,5'-di-te- rt-butyloxanilide,
2-ethoxy-2'-ethyloxanilide, N,N'-bis(3-dimethylaminopro-
pyl)oxalamide, 2-ethoxy-5-tert-butyl-2'-ethyloxanilide and mixtures
thereof with 2-ethoxy-2'-ethyl-5,4'-di-tert-butyloxanilide, and
mixtures of o- and p-methoxy- and of o- and p-ethoxy-disubstituted
oxanilides.
[0105] 2-(2-Hydroxyphenyl)-1,3,5-triazines, including but not
necessarily limited to 2,4,6-tris
(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,
2-(2-hydroxy-4-octyloxyphenyl) -4,6-bis
(2,4-dimethylphenyl)-1,3,5-triazi- ne,
2-(2,4-dihydroxyphenyl)-4,6-bis
(2,4-dimethylphenyl)-1,3,5-triazine,
2,4-bis(2-hydroxy-4-propyloxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazin-
e, 2-(2-hydroxy-4-octyloxyphenyl)
-4,6-bis(4-methylphenyl)-1,3,5-triazine,
2-(2-hydroxy-4-dodecyloxyphenyl)
-4,6-bis(2,4-dimethylphenyl)-1,3,5-triaz- ine,
2-[2-hydroxy-4-(2-hydroxy-3-butoxypropoxy)-phenyl]-4,6-bis(2,4-dimeth-
ylphenyl)-1,3,5-triazine,
2-[2-hydroxy-4-(2-hydroxy-3-octyloxypropoxy)phen-
yl-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.
[0106] Metal deactivators, including but not necessarily limited to
N,N'-diphenyloxalamide, N-salicylal-N'-salicyloylhydrazine,
N,N'-bis(salicyloyl)hydrazine, N,N'-bis
(3,5-di-tert-butyl-4-hydroxypheny- lpropionyl) hydrazine,
3-salicyloylamino-1,2,4-triazole, bis
(benzylidene)oxalodihydrazide, oxanilide, isophthalodihydrazide,
sebacobisphenyl hydrazide, N,N'-diacetyladipodihydrazide,
N,N'-bissalicyloyloxalodihydrazide and
N,N'-bissalicyloylthiopropionodihy- drazide.
[0107] Peroxide scavengers, including but not necessarily limited
to esters of .beta.-thiodipropionic acid, for example the lauryl,
stearyl, myristyl and tridecyl esters, mercaptobenzimidazole, the
zinc salt of 2-mercaptobenzimidazole, zinc dibutyldithiocarbamate,
dioctadecyl disulfide and pentaerythrityl
tetrakis(.beta.-dodecylmercapto)propionate.
[0108] Polyamide stabilizers, including but not necessarily limited
to copper salts in combination with iodides and/or phosphorus
compounds and salts of divalent manganese. Basic costabilizers,
including but not necessarily limited to melamine,
polyvinylpyrrolidone, dicyandiamide, triallyl cyanurate, urea
derivatives, hydrazine derivatives, amines, polyamides,
polyurethanes, alkali and alkaline earth metal salts of higher
fatty acids, for example zinc stearate, magnesium behenate,
magnesium stearate, sodium ricinoleate, potassium palmitate,
antimony pyrocatecholate and tin pyrocatecholate.
[0109] Nucleating agents, including but not necessarily limited to
sodium salts of adipic acid, diphenylacetic acid, and benzoic acid.
Clarifiers, including but not necessarily limited to
3,4-dimethylbenzylidine sorbital, which is a product of Milliken
Chemical of Inman, S.C., and is available under the trade name
Millad 3988.
[0110] Fillers and reinforcing agents, including but not
necessarily limited to calcium carbonate, silicates, glass fibres,
asbestos, talc, kaolin, mica, barium sulfate, metal oxides and
hydroxides, carbon black and graphite.
[0111] Benzofuranones and indolinones, including but not
necessarily limited to
3-[4-(2-acetoxyethoxy)phenyl]-5,7-di-tert-butyl-benzofuran-2-o- ne,
5,7-di-tert-butyl -3-[4-(2-stearoyloxyethoxy)phenyl]
benzofuran-2-one, 3,3'-bis [5,7-di-tert-butyl -3-(4-[2-hydroxy
ethoxy]-phenyl)benzofuran-2-- one], 5,7-di-tert-butyl
-3-(4-ethoxyphenyl)benzofuran-2-one,
3-(4-acetoxy-3,5-dimethylphenyl) -5,7-di-tert-butylbenzofuran-2-one
and 3-(3,5-dimethyl-4-pivaloyloxyphenyl)
-5,7-di-tert-butylbenzofuran-2-one.
[0112] The granules according to the present invention are suitable
for the stabilization of organic polymers or plastics against
thermal, oxidative or photoinduced degradation. Examples of such
polymers include, but are not necessarily limited to polymers of
monoolefins and diolefins, including, but not necessarily limited
to polypropylene, polyisobutylene, polybut-1-ene,
poly-4-methylpent-1-ene, polyisoprene or polybutadiene, as well as
polymers of cycloolefins, for instance of cyclopentene or
norbornene; furthermore polyethylene (which can be crosslinked),
for example high density polyethylene (HDPE), low density
polyethylene (LDPE), linear low density polyethylene (LLDPE) and
branched low density polyethylene (BLDPE). Polyolefins, i.e.,
polymers of monoolefins, such as polyethylene and polypropylene,
may be prepared by various processes, including: by means of free
radicals (usually at high pressure and high temperature) or by
means of a catalyst, where the catalyst usually contains one or
more metals from group IVb, Vb, VIb or VIII. These metals usually
contain one or more ligands, such as oxides, halides, alkoxides,
esters, ethers, amines, alkyls, alkenyls and/or aryls, which can be
either .pi. or .sigma.-coordinated. These metal complexes can be
free or fixed to supports, for example to activated magnesium
chloride, titanium(III) chloride, aluminum oxide or silicon oxide.
These catalysts can be soluble or insoluble in the polymerization
medium. The catalysts can be active as such in the polymerization
or further activators can be used, for example metal alkyls, metal
hydrides, metal alkyl halides, metal alkyl oxides or metal alkyl
oxanes, where the metals are elements from groups Ia, IIa and/or
IIIa. The activators can have been modified, for example, by means
of further ester, ether, amine or silyl ether groups. These
catalyst systems are usually known as Ziegler(-Natta), TNZ,
metallocene or single site catalysts (SSC).
[0113] The granules of the present invention may further be used to
process mixtures of the previously identified polymers, for example
mixtures ofpolypropylene with polyisobutylene, polypropylene with
polyethylene (for example PP/HDPE, PP/LDPE) and mixtures of
different types of polyethylene (for example LDPE/HDPE).
Additionally, the granules may be used with copolymers of
monoolefins and diolefins with each other or with other vinyl
monomers, for example ethylene-propylene copolymers, linear low
density polyethylene (LLDPE) and its mixtures with low density
polyethylene (LDPE), propylene-but-1-ene, propylene-isobutylene,
ethylene-but-1-ene, ethylene-hexene, ethylene-methylpentene,
ethylene-heptene, ethylene-octene, propylene-butadiene,
isobutylene-isoprene, ethylene-alkyl acrylate, ethylene-alkyl
methacrylate, ethylene-vinyl acetate copolymers or copolymers
thereof with carbon monoxide or ethylene-acrylic acid copolymers
and their salts (ionomers) and terpolymers of ethylene with
propylene and a diene, such as hexadiene, dicyclopentadiene or
ethylidenenorbornene; as well as mixtures of such copolymers and
their mixtures with polymers previously identified, for example
polypropylene-ethylene-propylene copolymers, LDPE-ethylene-vinyl
acetate copolymers, LDPE-ethylene-acrylic acid copolymers,
LLDPE-ethylene-vinyl acetate copolymers, LLDPE-ethylene-acrylic
acid copolymers and polyalkylene-carbon monoxide copolymers with an
alternating or random structure, and mixtures thereof with other
polymers, for example polyamides. Other polymer systems such as
hydrocarbon resins (for example C.sub.5-C.sub.9), including
hydrogenated modifications thereof(for example tackifing resins)
and mixtures of polyalkylenes and starch, polystyrene,
poly(p-methylstyrene), poly(.alpha.-methylstyrene), and copolymers
of styrene or .alpha.-methylstyrene with dienes or acrylic
derivatives, for example styrene-butadiene, styrene-acrylonitrile,
styrene-alkyl methacrylate, styrene-butadiene-alkyl acrylate,
styrene-maleic anhydride, styrene-acrylonitrile-methyl acrylate;
high impact strength mixtures of styrene copolymers and another
polymer, for example a polyacrylate, a diene polymer or an
ethylene-propylene-diene terpolymer; and block copolymers of
styrene, for example styrene-butadiene-styrene,
styrene-isoprenestyrene, styrene-ethylene/butylene-styrene or
styrene-ethylene/propylene-styrene may be processed with the
granules of the present invention.
[0114] Graft copolymers of styrene or .alpha.-methylstyrene, for
example styrene on polybutadiene, styrene on polybutadiene-styrene
or polybutadiene-acrylonitrile copolymers; styrene and
acrylonitrile (or methacrylonitrile) on polybutadiene; styrene,
acrylonitrile and methyl methacrylate on polybutadiene; styrene and
maleic anhydride on polybutadiene; styrene, acrylonitrile and
maleic anhydride or maleimide on polybutadiene; styrene and
maleimide on polybutadiene, styrene and alkyl acrylates or
methacrylates on polybutadiene, styrene and acrylonitrile on
ethylene-propylene-diene terpolymers, styrene and acrylonitrile on
polyalkyl acrylates or polyalkyl methacrylates, styrene and
acrylonitrile on acrylate-butadiene copolymers, as well as mixtures
thereof with the copolymers of the previously identified styrene or
.alpha.-methylstyrene with dienes or acrylic derivatives, for
instance the copolymer mixtures known as ABS, MBS, ASA or AES
polymers may be processed.
[0115] Other processed polymers include halogen-containing
polymers, such as polychloroprene, chlorinated rubber, chlorinated
or chlorosulfonated polyethylene, copolymers of ethylene and
chlorinated ethylene, epichlorohydrin homo- and copolymers, in
particular polymers from halogen-containing vinyl compounds, for
example polyvinyl chloride, polyvinylidene chloride, polyvinyl
fluoride, polyvinylidene fluoride, as well as copolymers thereof,
for example vinyl chloride-vinylidene chloride, vinyl
chloride-vinyl acetate or vinylidene chloride-vinyl acetate.
Polymers derived from .alpha.,.beta.-unsaturated acids and
derivatives thereof, such as polyacrylates and polymethacrylates,
polymethacrylates, polyacrylamides and polyacrylonitriles which
have been impact modified by means of butyl acrylate. Copolymers of
the monomers from .alpha.,.beta.-unsaturated acids with each other
or with other unsaturated monomers, for instance
acrylonitrile-butadiene, acrylonitrile-alkyl acrylate,
acrylonitrile-alkoxyalkyl acrylate or acrylonitrile-vinyl halide
copolymers or acrylonitrile-alkyl methacrylate-butadiene
terpolymers. Polymers 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, polyvinyl butyral, polyallyl phthalate or
polyallylmelamine; and their copolymers with olefins. Homopolymers
and copolymers of cyclic ethers, such as polyalkylene glycols,
polyethylene oxide, polypropylene oxide or copolymers thereof with
bisglycidyl ethers. Polyacetals, such as polyoxymethylene and those
polyoxymethylenes which contain comonomers, for example ethylene
oxide; polyacetals modified with thermoplastic polyurethanes,
acrylates or MBS. Polyphenylene oxides and sulfides, and mixtures
thereof with styrene polymers or polyamides. Polyurethanes derived
from polyethers, polyesters or polybutadienes with terminal
hydroxyl groups on the one hand and aliphatic or aromatic
polyisocyanates on the other, and precursors thereof. Polyamides
and copolyamides derived from diamines and dicarboxylic acids
and/or from aminocarboxylic acids or the corresponding lactams,
such as nylon 4, nylon 6, nylon 6/6, 6/10, 6/9, 6/12, 4/6, and
12/12, nylon 11, nylon 12, aromatic polyamides obtained from
m-xylene, diamine and adipic acid; polyamides prepared from
hexamethylenediamine and isophthalic and/or terephthalic acid and
optionally an elastomer as modifier, for example
poly-2,4,4-trimethylhexamethylene terephthalamide or
poly-m-phenylene isophthalamide. Block copolymers of the
aforementioned polyamides with polyolefins, olefin copolymers,
ionomers or chemically bonded or grafted elastomers; or with
polyethers, for instance with polyethylene glycol, polypropylene
glycol or polytetramethylene glycol. Further, EPDM- or ABS-modified
polyamides or copolyamides; and polyamides condensed during
processing ("RIM polyamide systems"). Polyureas, polyimides,
polyamide-imides and polybenzimidazoles. Polyesters derived from
dicarboxylic acids and diols and/or from hydroxycarboxylic acids or
the corresponding lactones, such as polyethylene terephthalate,
polybutylene terephthalate, poly-1,4-dimethylolcyclohexane
terephthalate and polyhydroxybenzoates as well as block
polyether-esters derived from polyethers having hydroxyl end
groups; also polycarbonate- or MBS-modified polyesters.
Polycarbonates, polyester carbonates, polysulfones, polyether
sulfones and polyether ketones. Crosslinked polymers derived from
aldehydes on the one hand and phenols, urea or melamine on the
other, such as phenol-formaldehyde resins, urea-formaldehyde resins
and melamine-formaldehyde resins. Drying and non-drying alkyd
resins. Unsaturated polyester resins 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 inflammability.
Crosslinkable acrylic resins, derived from substituted acrylic
esters, for example epoxy acrylates, urethane acrylates or
polyester acrylates. Alkyd resins, polyester resins or acrylate
resins crosslinked with melamine resins, urea resins,
polyisocyanates or epoxy resins. Crosslinked epoxy resins derived
from polyepoxides, for example from bisglycidyl ethers or from
cycloaliphatic diepoxides. Natural polymers, such as cellulose,
natural rubber, gelatin and derivatives thereof which are
chemically modified in a polymer-homologous manner, such as
cellulose acetates, cellulose propionates and cellulose butyrates,
or cellulose ethers, such as methylcellulose; and colophony resins
and derivatives. Mixtures (polyblends) of polymers as mentioned
above, for example PP/EPDM, polyamide/EPDM or ABS, PVC/EVA,
PVC/ABS, PVC/MBS, PC/ABS, PBTP/ABS, PC/ASA, PC/PBT, PVC/CPE,
PVC/acrylates, POM/thermoplastic PUR, PC/thermoplastic PUR,
POM/acrylate, POM/MBS, PPO/HIPS, PPO/PA 6.6 and copolymers,
PA/HDPE, PA/PP, PA/PPO. Natural and synthetic organic substances
which are pure monomeric compounds or mixtures thereof, for example
mineral oils, animal or vegetable fats, oils and waxes, or oils,
waxes and fats based on synthetic esters (for example phthalates,
adipates, phosphates or trimellitates), and blends of synthetic
esters with mineral oils in any desired weight ratios, as used, for
example, as spinning preparations, and aqueous emulsions thereof.
Aqueous emulsions of natural or synthetic rubbers, for example
natural rubber latex or latexes of carboxylated styrene-butadiene
copolymers.
[0116] The granules of the present invention may additionally
comprise one or more conventional plastic additives; preferably
such additives are selected from the group consisting of sterically
hindered amines (HALS), sterically hindered phenols, phosphites or
phosphonites, hydrotalcites, metal oxides, metal carbonates,
further metal soaps, antistatics, antiblocking agents,
flameproofing agents, thioesters, internal lubricants, pigments, UV
absorbers and further light stabilizers. The further plastics
additive or additives may be in any convenient physical form, e.g.,
crystalline, powder, pellets, granules, dispersions or liquids.
Preferred organic polymers are synthetic polymers and in particular
the polymers from group 1, especially polyethylene and
polypropylene. The granules are expediently added to the organic
polymers to be stabilized in amounts of from 0.01 to 10%,
preferably from 0.01 to 5%, based on the total weight of the
organic polymer to be stabilized. The granules according to the
invention and any further additives can be incorporated into the
organic polymer by known methods, for example before or during
molding or by applying the dissolved or dispersed granules to the
polymer, if necessary with subsequent evaporation of the solvent.
The granules can also be used for the production of so-called
masterbatches. The method for the stabilization of an organic
polymer comprising incorporating into said polymer an effective
stabilizing amount, as described above, of the low-dust granules is
another object of the instant invention. The preferred embodiments
for the low-dust granules and the polymer apply analogously. The
polymer stabilized in this way can be converted into a wide variety
of forms in a conventional manner, for example into films, fibers,
tapes, molding compositions or profiles.
[0117] Manufacture and testing of the stabilizer granules of the
present invention may be accomplished as described in the following
examples and procedures.
Balanced Hardness Test
[0118] The hardness test was designed to evaluate the formed
pellets for the duel criteria of stabilizer handling conformity and
favorable polymer processing characteristics. The hardness test
included laying a single 3 mm diameter pellet of a given
composition on a testing platform and then applying a compressive
load across the pellet. The pellet was placed between two parallel
non-cushioned steel plates with an increasing load applied to the
top plate as a factor of time. The tested pellets generally
produced a characteristic load verses time plot, with a maximum
load reached at the point where the pellet begins to disintegrate
into small particles. The maximum load divided by the length of the
33 mm diameter test pellet was the parameter used to measure
hardness for a given pellet composition. It is believed that the
hardness value increases linearly with the diameter of the pellet.
The hardness test provided a toughness or crushing determination,
with parameters in pounds per inch. Granule testing was typically
accomplished over several replicate test specimens, such as about
10 to about 20 test specimens, with the averaging of the results.
The resulting graph of the averaged tests, as seen in FIG. 1, has
the x-axis as either time or crosshead displacement, as the
crosshead is moving at a constant rate providing either time
(minutes) or displacement (millimeters). A typical and convenient
rate for the crosshead movement is 0.02 in/min. FIG. 1 illustrates
a load versus time plot for the pellets processed from Ethanox.RTM.
antioxidant with mixed isopropanol at 1 part by weight and
cyclohexane at 3 parts by weight, using 9 parts by weight
processing agent and 100 part by weight Ethanox.RTM.
antioxidant.
Pelletization of the Sterically Hindered Phenol Antioxidant
[0119] The organic processing agents are combined with the first
antioxidant so that at least 1 gram of the first antioxidant is
dispersed in every 100 mL of processing agent. The antioxidant may
be proportionally added to the selected processing agent, or the
organic processing agent may be added to the antioxidant powder.
The resulting solution is brought in situ into contact with the
remaining antioxidant powder so as to effect the formation of a
paste of the antioxidant which is suitable for pelletization. The
concentration of the organic processing agent, i.e., selected
solvent plus alcohol, required to form the paste which is suitable
for pelletization generally ranges from about 3 parts by weight
organic processing agent per 97 parts by weight of additive powder,
i.e., sterically hindered phenol antioxidant plus optionally
secondary phosphite antioxidant and acid neutralizer, to about 20
parts by weight of organic processing agent per 80 parts by weight
of additive powder. Generally, the organic processing agent
provides from about 20 weight percent to about 50 weight percent of
an alcohol. Cylindrical pellets were formed in a die press.
Pellet Example 1
Ethanox.RTM. 330.RTM. Antioxidant Pellets Formed with
Cyclohexane
[0120] Cylindrical pellets of
1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-buty- l-4-hydroxybenzyl)
benzene powder (Ethanox.RTM. 330 Antioxidant) were prepared by
combining 20 lb of Ethanox.RTM. 330 powder with 2.4 lb cyclohexane
solvent and tumble blended for 5 minutes to obtain a homogeneous
mixture. The homogeneous mixture was fed, at 55-60 lb/hr rate, to a
Kahl Model 14-175 Pellet Press equipped with a die plate containing
holes of 3 mm diameter and 10.5 mm pressway length and operating at
a rotor speed of nominally 100 rpm. The output product of the
pellet mill was dried for 60 minutes in a forced-air oven operating
under nitrogen atmosphere and a temperature of 100.degree. C.,
after which the dried product dry sieved with a US Standard No. 12
screen to remove the fines (minus 12 mesh powder). The Ethanox.RTM.
330 particles thus obtained were cylindrical pellets of 3 mm
diameter with a hardness of 18 lb/in.
Pellet Example 2
Ethanox.RTM. 330.RTM. Antioxidant Pellets Formed with Mixed
Cyclohexane/Isopropanol Organic Processing Agent
[0121] The procedures of Example 1 were repeated, except the
processing solvent used to prepare the feed mixture consisted of
1.8 lb of cyclohexane and 0.6 lb of isopropanol. The Ethanox.RTM.
330 particles thus obtained were cylindrical pellets of 3 mm
diameter with a hardness of 15 lb/in.
Comparative Pellet Example 1
[0122] 4000 grams of
1,3,5-trimethyl-2,4,6-tris-(3,5-di-tert-butyl-4-hydro- xybenzyl)
benzene powder, with no organic processing agent added, was fed
into a Kahl Model 14-175 Pellet Mill operating at 100 rpm rotor
speed and equipped with a die plate having holes of 2 mm diameter
and 6 mm pressway length. The product from the pellet mill
consisted of nearly all fine powder with a small proportion of very
soft pellets.
Pellet Example 3
Irganox 3114 Antioxidant Pellets Formed with Cyclohexane Processing
Solvent
[0123] Cylindrical pellets of
1,3,5-Tris-(3,5-di-t-butyl-4-hydroxybenzyl)i- socyanurate powder
(Irganox 3114 obtained from Ciba Specialty Chemicals) were prepared
by combining 20 lb of Irganox 3114 powder and 2 lb of cyclohexane
solvent and tumble blending for 5 minutes to obtain a homogeneous
feed mixture. The homogeneous mixture was fed, at nominally 85
lb/hr rate, to a Kahl Model 14-175 Pellet Press equipped with a die
plate containing holes of 3 mm diameter and 10.5 mm pressway length
and operating at a rotor speed of nominally 100 rpm. The output
product of the pellet mill was dried for 70 minutes in a forced-air
oven operating under nitrogen atmosphere and a temperature of
100.degree. C. The dried product was dry sieved with a US Standard
No. 8 screen to remove the fines (minus 8 mesh powder). The Irganox
3114 particles thus obtained were cylindrical pellets of 3 mm
diameter with a hardness of 22 lb/in.
Pellet Example 4
Irganox 3114/Secondary Phosphite Blend Pellets Formed with Mixed
Cyclohexane/Isopropanol Processing Solvent
[0124] Cylindrical pellets having a blend of
1,3,5-Tris-(3,5-di-t-butyl-4-- hydroxybenzyl)isocyanurate hindered
phenol antioxidant (Irganox 3114 obtained from Ciba Specialty
Chemicals) with tris(2,4-di-t-butylphenyl)ph- osphite secondary
antioxidant (Irgafos 168 obtained from Ciba Specialty Chemicals) in
1:1 proportions by weight were prepared by combining 10 lb each of
Irganox 3114 and Irgafos 168 powders and tumble blending the
mixture for 5 minutes. 1.2 lb of cyclohexane and 1.2 lb of
isopropanol were added and the mixture was tumble blended for an
additional 5 minutes was done to obtain a homogeneous feed mixture.
The homogeneous feed mixture was fed, at nominally 75 lb/hr rate,
to a Kahl Model 14-175 Pellet Mill equipped with a die plate with
holes of 3 mm diameter and 10.5 mm pressway length. The output of
the pellet mill was dried for 65 minutes in a forced air oven
operating under nitrogen atmosphere at a temperature of 100.degree.
C. The dry product was then dry sieved with a US Standard No. 8
screen to remove the fines (minus 8 mesh material). The finished
particles thus obtained were cylindrical pellets having a diameter
of nominally 3 mm and a hardness of 20 lb/in.
Pellet Example 5
Ethanox.RTM. 330 Antioxidant/Secondary Phosphite Antioxidant Blend
Pellets Formed with Methylethylketone Processing Solvent
[0125] Cylindrical pellets having a blend of Ethanox.RTM. 330
Antioxidant with tris(2,4-di-t-butylphenyl) secondary phosphite
antioxidant (Irgafos 168 obtained from Ciba Specialty Chemicals) in
1:2 proportions by weight were prepared by combining 13.3 lb of
Irgafos 168 powder and 6.7 lb of Ethanox.RTM. 330 Antioxidant
powder and tumble blending for 5 minutes. 1.5 lb of
methylethylketone solvent were added to the blended powders which
was then tumble blended for 5 minutes to obtain a homogeneous feed
mixture. The homogeneous feed mixture was fed, at nominally 65-70
lb/hr rate, to a Kahl Model 14-175 Pellet Mill equipped with a die
plate with holes of 3 mm diameter and 9 mm pressway length. The
output of the pellet mill was dried for about 2 hours in a forced
air oven operating under nitrogen atmosphere at a temperature of
105.degree. C. The dried product was dry sieved with a US Standard
No. 8 screen to remove the fines (minus 8 mesh material). The
finished particles thus obtained were cylindrical pellets having a
diameter of nominally 3 mm and a hardness of 14 lb/in.
Pellet Example 6
Ethanox.RTM. 330 Antioxidant/Secondary Phosphite Antioxidant Blend
Pellets Formed with Mixed Methylethylketone/Acetone
[0126] Example 5 was repeated using as an organic processing agent
1.0 lb of methylethylketone and 0.5 lb. of acetone, and with the
feeding rate to the pellet mill at nominally 55 lb/hr. The finished
particles obtained were cylindrical pellets having a diameter of
nominally 3 mm and a hardness of 14 lb/in.
Pellet Example 7
Ethanox.RTM. 330 Antioxidant/Acid Neutralizer Blend Pellets Formed
with Methylethylketone Solvent
[0127] Cylindrical pellets having a blend of Ethanox.RTM. 330
Antioxidant with calcium stearate acid neutralizer in 60:40
proportion by weight were prepared by combining 4.8 lb of
Ethanox.RTM. 330 Antioxidant powder with 3.2 lb of calcium stearate
powder (Synpro 114-40 calcium stearate obtained from Ferro
Corporation of Walton Hills, Ohio) and tumble blending the powders
for 3 minutes. 0.6 lb of methylethylketone were added and the
mixture was tumble blended for 3 minutes to obtain a homogeneous
feed mixture. The homogeneous feed mixture was fed, at a rate of
nominally 40 lb/hr, to a Kahl Model 14-175 pellet mill equipped
with a die plate having holes of 3 mm diameter and 12 mm pressway
length. The output of the pellet mill was dried for about one hour
in a forced air oven operating under nitrogen atmosphere and at a
temperature of 90.degree. C. and then dry sieved with a US Standard
No. 12 screen to remove the fines (minus 12 mesh particles). The
finished particles thus obtained were cylindrical pellets having a
diameter of nominally 3 mm and a hardness of 24 lb/in.
Pellet Example 8
Pellets of Ethanox.RTM. 330 Antioxidant/Secondary Phosphite
Antioxidant/Acid Neutralizer Blend
[0128] Pellets having a blend of Ethanox.RTM. 330 Antioxidant
powder with a secondary phosphite antioxidant powder (Irgafos 168
Antioxidant obtained from Ciba Specialty Chemicals) and two acid
neutralizers (DHT-4A obtained from Kyowa Chemical Industry Co.,
LTD, and Hydense 5862 calcium stearate powder obtained from
Baerlocher USA). Three different processing agents were used
combined with 5.96 lb of Ethanox.RTM. 330 powder, 8.6 lb of Irgafos
168 powder, 4.64 lb of DHT-4A powder, and 0.8 lb of calcium
stearate powder in a tumble blender and blending for 5 minutes. 2.0
lb of the processing agent was added and tumble blending was done
for 5 minutes to obtain a homogeneous feed mixture. The homogeneous
feed mixture was fed, at about 40-50 lb/hr rate, to a Kahl Model
14-175 Pellet Mill equipped with a die plate having holes of 3 mm
diameter and 10.5 mm pressway length. The product was then dried
for about 70 minutes in a forced air oven operating in nitrogen
atmosphere and at a temperature of 100.degree. C. The dried product
was dry sieved with a US Standard No. 12 screen to remove the fines
(minus 12 mesh particles). The three pellet samples were prepared
with the following processing agents: Sample A) isopropanol; Sample
B) mixture of isopropanol and methylethylketone in 25:75
proportions by weight; and Sample C) methylethylketone. The
finished particles of Samples A, B, and C thus obtained in this
manner were cylindrical pellets of nominally 3 mm diameter having
hardnesses of 12, 16, and 20 lb./in, respectively.
Hosokawa Flowability of Antioxidant Blend Pellets
[0129] Hosokawa Flowability of the following blends was tested
using known procedures, namely:
[0130] 1) Measuring five standard powder properties, namely aerated
bulk density, packed bulk density, angle of repose, angle of
spatula, and particle uniformity (from sieve size analyses);
[0131] 2) From the aerated and packed bulk densities, calculating a
factor called the compressibility;
[0132] 3) From correlation charts, assigning an index rating (0-25
scale) to the angle of repose, the angle of spatula, the particle
uniformity, and the compressibility; and
[0133] 4) Summing the four index ratings of Step 3 to arrive at the
numerical value of the Hosokawa Flowability.
[0134] The following were the results:
1 Hosokawa Blend Composition* Processing Solvent** Flowability 100%
E-330 9.0 MEK + 3 IPA 83 50% E-330/ 10.0 MEK 78 50% I-168 33%
E-330/ 10.0 MEK 83 67% I-168 50% E-314/ 6.0 CHX + 82 50% I-168 6.0
IPA 100% E-330 Not Pelletized 44 Powder 100% E-314 9.0 cyclohexane
+ 85 3.0 IPA 33% E-314/ 6.0 cyclohexane + 85 67% I-168 6.0 IPA
[0135] Formation of Agglomerates of Sterically Hindered Phenol
Additive System
[0136] In the examples that follow, all portions of material is
given in parts by weight. Unless noted otherwise, the agglomeration
process was performed by: 1) adding the indicated proportions of
the processing aid liquid and the additive powder to a glass
Erlenmeryer flask; 2) admixing the materials of Step (1) with a
spatula until a paste-like slurry formed; 3) rotating the flask at
about 60 rpm with a rotoevaporator head while simultaneously
tapping the flack gently with the fingers (to stimulate the
tumbling action of a drum or pin agglomerator apparatus) to affect
the agglomeration into spherical particles; 4) transferring the
agglomerated particles to a petri dish for drying in a forced-air
oven at the indicated temperature. In those cases where the
"additive powder" of Step (1) comprised a mixture of two or more
powder components, the powder mixture was dry blended prior to
adding the processing aid liquid.
[0137] In the examples, processability testing or agglomerate
hardness measurements to determine the processability
characteristics of the agglomerates, i.e. hardness and attrition
resistance was determined by subjecting the agglomerates to manual
manipulation so as to observe the friability of the
agglomerate.
Formation of Agglomerates
Agglomerate Example I
Agglomeration of ETHANOX.RTM. 330/Hydrotalcite Additive System
[0138] 1 part of hydrotalcite powder (commercially available from
Kyowa Chemical Company under the trademark DHT-4V) and 2 parts of
1,3,5-trimethyl-1-2,4,6-tris-(3,5-di-tert-butyl-4-hydroxylbenzyl
benzene), commercially available from Albemarle Corporation under
the trademark ETHANOX.RTM. 330, were dry blended to form the
desired additive system powder composition. This additive system
powder was agglomerated using 0.79 parts methanol processing aid
per 5 parts of powder. The resulting agglomerate was dried at
85.degree. C. The dried agglomerate was dry sieved with a U.S.
Standard No. 8, 19 screen to remove the fine particles (-18 mesh)
and to obtain the desired additive system agglomerate particles in
80% yield. The resulting product consisted of essentially spherical
particles ranging in a size from about 1 mm to about 4 mm in
diameter. The resulting product of agglomerated particles were
subject to manual characterization and judged to have very good
hardness and therefore good resistance to particle attrition during
conveying operations.
Agglomerate Example II
Agglomeration of ETHANOX.RTM. 330/Hydrotalcite/Secondary Phosphite
Additive System
[0139] 42 parts ETHANOX.RTM. 330 Antioxidant, 52 parts of a
commercially available secondary phosphite antioxidant, available
from Ciba Specialty Chemicals under the trademark IRGAFOS 168, and
16 parts of DHT-4V hydrotalcite were dry blended to form the
desired additive system powder composition. The additive system was
agglomerated using 0.79 parts of denatured ethanol process aid per
6 parts of additive system powder composition. The resulting
agglomerated particles were subjected to drying at 83.degree. C.
The resulting dried agglomerate product particles were dry sieved
with a U.S. Standard No. 18 screen to give 77% yield of essentially
spherical particles ranging in diameter from about 1 to about 5 mm.
Manual characterization of the particles indicated very good
hardness and therefore good resistance to particle attrition during
conveying operations.
Agglomerate Example III
Agglomeration of ETHANOX.RTM. 330/Zinc Oxide/Secondary Phosphite
Additive System A
[0140] Example II was essentially repeated but with 44 parts of
ETHANOX.RTM. 330 Antioxidant, 38 parts of IRGAFOS 168, and 18 parts
of ZnO (Grade Az066L obtained from Midwest Zinc Company) as the
desired additive system powder composition. Manual characterization
of the dried agglomerate particles indicated very good particle
hardness and therefore good resistance to particle attrition during
conveying operations.
Agglomerate Example IV
Agglomeration of IRGANOX 1010/Hydrotalcite/Secondary Phosphite
Additive System
[0141] 5.3 parts of pentaerythritol ester of
.beta.-(3,5-di-tert-butly-4-h- ydroxyphenyl) propionic acid, a
commercially available hindered phenolic antioxidant obtainable
from Ciba Specialty Chemicals under the trademark IRGANOX 1010,
1.59 parts of DHT-4V acid neutralizer, and 2.61 parts of IRGAFOS
168 were dry blended to obtain the desired additive system powder
composition. Agglomeration of this additive system powder blend was
affected using 1.1 parts of isopropanol as the processing aid per
9.5 parts of powder blend. The resulting agglomerate particles were
dried at 85.degree. C. The resulting dried agglomerates were to
essentially spherical of nominally 1-5 mm diameter and having very
good hardness.
Agglomerate Example V
Agglomeration with Acetone/Methanol
[0142] 1 part of DHT-4V hydrotalcite and 2 parts ETHANOX.RTM. 330
antioxidant were dry blended to form an additive system powder mix.
The additive powder blend was agglomerated using a processing aid
liquid, 0.79 parts of a 50:50 mixture of acetone and methanol
having 5 grams of ETHANOX.RTM. 330 Antioxidant per 100 mL cosolvent
processing aid dissolved therein. The resulting agglomerate was
dried at 85.degree. C. The resulting agglomerate particles were
then dry sieved with a U.S. Standard No. 18 screen to remove the
fine particles and to obtain the desired additive system
agglomerate particles in 80% yield. The resulting agglomerate
particles were essentially spherical and ranged in size from about
1 mm to about 5 mm in diameter. Using manual manipulation the
particles were judged to have a very good hardness. Moreover, the
agglomerated particles obtained with the processing aid containing
acetone cosolvent were considerably harder than the agglomerate of
Example I.
Agglomerate Example VI
Agglomeration with Acetone/Ethanol
[0143] 1 part of DHT-4V hydrotalcite and 2 parts ETHANOX.RTM. 330
antioxidant were dry blended to form an additive system powder mix.
This additive powder blend was agglomerated using as a processing
aid liquid, 0.79 parts of a 50:50 mixture of acetone and denatured
ethanol having 5 grams of ETHANOX.RTM. 330 Antioxidant per 100 mL
cosolvent processing aid dissolved therein. The resulting
agglomerate was dried at 85.degree. C. The resulting agglomerate
particles were then dry sieved with a U.S. Standard No. 18 screen
sieve to remove the fine particles and to obtain the desired
additive system agglomerate particles in 80% yield. The resulting
agglomerated particles were essentially spherical and ranged in
size from about 1 mm to about 5 mm in diameter. Using manual
manipulation, the particles were judged to have a very good
hardness. Moreover, the agglomerated particles obtained with the
processing aid containing acetone cosolvent were considerably
harder than the agglomerates of Example 1.
Agglomerate Example VII
Agglomeration with Acetone/Methanol
[0144] 1 part of DHT-4V hydrotalcite and 2 parts of ETHANOX.RTM.
330 antioxidant were dry blended to form an additive system powder
mix. This additive powder blend was agglomerated using as a
processing aid liquid, 0.79 pts of a 30:70 mixture of acetone and
methanol having 5 grams of ETHANOX.RTM. 330 Antioxidant per 100 mL
cosolvent processing aid dissolved therein. The resulting
agglomerate was dried at 85.degree. C. The resulting agglomerate
particles were dry sieved with a U.S. Standard No. 18 screen to
remove the fine particles and to obtain the desired additive system
agglomerate particles in 80% yield. The resulting agglomerated
particles were essentially spherical and ranged in size from about
1 mm to about 5 mm in diameter. Using manual manipulation, the
particles were judged to have a hardness which was intermediate to
that of the corresponding particles of Examples 1 and IV.
Agglomerate Example VIII
Agglomeration with Acetone/Ethanol
[0145] 1 part of DHT-4V hydrotalcite and 2 parts ETHANOX.RTM. 330
antioxidant were dry blended to form an additive system powder mix.
This additive powder blend was agglomerated using as a processing
aid liquid, 0.79 pats of a 30:70 mixture of acetone and denatured
ethanol having 5 grams of ETHANOX.RTM. 330 Antioxidant per 100 mL
cosolvent processing aid dissolved therein. The resulting
agglomerate was dried at 85.degree. C. The resulting particles were
then dry sieved with U.S. Standard No. 18 screen to remove the fine
particles and to obtain the desired system agglomerate particles in
80% yield. The resulting agglomerated particles were essentially
spherical and ranged in size from about 1 mm to about 5 mm in
diameter. Using manual manipulation, the particles were judged to
have a hardness which was intermediate to that of the corresponding
particles of Examples I and V. Agglomerate Examples V-VIII
illustrate that the introduction of solvent and dissolved phenolic
antioxidant into the processing aid produced an increase in the
hardness of the agglomerate particles. In addition, Agglomerate
Examples VII and VIII illustrate that the hardness of the
agglomerate particles is controlled by the relative proportion of
the solvent and the hardness varied inversely with the relative
proportion of the alcohol. The specific examples herein disclosed
are to be considered as being primarily illustrative. Various
changes beyond those described will occur to those skilled in the
art and such changes are to be understood as forming a part of this
invention as they fall within the spirit and scope of the appended
claims.
Agglomerate Example IX
Agglomeration with Toluene/Ethanol
[0146] The processing aid liquid (A) was prepared by admixing
ETHANOX.RTM. 330 antioxidant powder (10 parts), toulene (47.2
parts), denatured ethanol (42.8 parts). The agglomeration process
was performed on 1 part (A) admixed with 5 parts of additional
ETHANOX.RTM. 330 antioxidant powder. The resulting agglomerated
particles were dried for about 20 minutes in the oven beginning at
about 70.degree. C. and gradually increasing the temperature to
about 115.degree. C. The dried agglomerate consisted of essentially
spherical particles ranging from 1 mm to 4 mm in diameter. The
resulting dried agglomerate particles were subjected to manual
characterization and judged to have very good hardness and
therefore good resistance to particle attrition during conveying
operations.
[0147] For comparative purposes, the ETHANOX.RTM. 330 antioxidant
powder was agglomerated under the same conditions as above
described but with two different processing aid liquids (B) and
(C). Processing aid liquid (B) was a saturated solution of
ETHANOX.RTM. 330 antioxidant dissolved in denatured ethanol, and
processing aid liquid (C) consisted of 10 parts of ETHANOX.RTM. 330
antioxidant dissolved in toulene. With (B), the wet agglomerated
spherical particles that formed mostly disintegrated into fine
powder during the drying operation, and the few dried spherical
particles that remained were extremely soft and exhibited very low
abrasion resistance. With (C), the tumbling action of the
agglomeration apparatus failed to produce the desired spherical
particles, leaving an essentially continuous slurry mass instead.
This comparative example illustrates that the processing liquid aid
of the instant invention is necessary both to form the desired
spherical agglomerated particles and to impart the desired hardness
to the dried agglomerated particles.
Agglomerate Example X
Agglomeration with Phosphite Antioxidant
[0148] The agglomeration process with agglomeration aid of (A)
Example IX essentially was repeated but with the powder component
replaced with a blend consisting of ETHANOX.RTM. 330 antioxidant
powder (1 part) and IRGAFOS 168 phosphite powder (1 part)
(tris-(2,4-di-tert-butylphenyl) phosphite), (a commercial secondary
phosphite antioxidant product obtained from Ciba Specialty
Chemicals). The dried agglomerate particles thus obtained
essentially were spherical in shape, were nominally 1 to 4 mm in
diameter, an when subjected to manual manipulation were judged to
have very good hardness and therefore good resistance to particle
attrition during conveying operations.
Agglomeration Example XI
Agglomeration with IRGANOX 1010 blend with Secondary Phosphite
[0149] The process aid liquid (D) was prepared by admixing IRGANOX
1010 antioxidant powder (pentaerythrityl ester of
.beta.-(3,5-di-tert-butyl-4-- hydroxyphenyl) propionic acid) (6
parts) (a commercial hindered phenolic antioxidant obtained from
Ciba Specialty Chemicals), acetone (47 parts), and methanol (47
parts). Processing aid liquid (E) was prepared by admixing IRGANOX
1010 (6 parts), acetone (70.5 parts), and methanol (23.5 parts). A
powder blend consisting of equal parts by weight of IRGANOX 1010
and IRGAFOS 168 also was prepared. The agglomeration of the powder
blend was affected by utilizing 0.55 parts of agglomeration aid
liquid with 5 parts of blended powder followed by drying in the
oven at 71.degree. for 30 minutes. The dried agglomerate particles
thus obtained using processing aid liquids (D) and (E) essentially
were spherical in shape, were nominally 1 to 4 mm in diameter, and
when subjected to manual manipulation were judged to have very good
hardness and therefore good resistance to particle attrition during
conveying operations. Moreover, the agglomerate particles made with
processing aid (E) were considerably harder than those made with
processing aid (D), thereby demonstrating that the hardness of the
agglomerated particles is increased as the proportion of alcohol in
the agglomeration aid liquid is decreased.
Agglomeration Example XII
Agglomeration with Acetone/Methanol
[0150] The processing aid liquid (F) was prepared in the same
manner as the processing aid liquid (D) of Example XI except
ETHANOX.RTM. 330 antioxidant powder was substituted for the IRGANOX
1010 antioxidant powder. ETHANOX.RTM. 330 antioxidant powder was
agglomerated with processing aid liquid (F) and subsequently dried
by repeating the procedures utilized in Example XI. The dried
agglomerate particles of ETHANOX.RTM. 330 antioxidant thus obtained
were essentially spherical in shape, were nominally 1 to 5 mm in
diameter, and when subjected to manual manipulation were judged to
have very good hardness and therefore good resistance to particle
attrition during conveying operations.
* * * * *