IMPROVED PROCESSIBILITY AND LACING RESISTANCE WHEN SILANIZED PIGMENTS ARE INCORPORATED IN POLYMERS

AMELIORATION DE L'APTITUDE DE POLYMERES AU TRAITEMENT ET DE LEUR RESISTANCE AU DEVELOPPEMENT D'IMPERFECTIONS PAR INCORPORATION DE PIGMENTS TRAITES AU SILANE

English Abstract

White-pigmented polymers (particularly, polyolefins such as polyethylene) containing white pigments treated with at least one silane or a mixture of at least one silane and at least one polysiloxane are disclosed to improve processibility in compounding and improve performance properties such as lacing resistance in a polymeric matrix.

French Abstract

Polymères à pigments blancs (notamment des polyoléfines comme le polyéthylène), contenant des pigments blancs traités avec au minimum un silane ou avec un mélange d'au minimum un silane et d'au minimum un polysiloxane pour améliorer leur aptitude au traitement au cours du mélange et pour améliorer les caractéristiques de performance d'une matrice polymérique telles que sa résistance au développement d'imperfections.

Claims

12
CLAIMS:
1. A polymer matrix comprising polymer and about 50 to about 87% by weight
silanized
TiO2 pigment, based on the weight of the polymer matrix, exhibiting enhanced
processibility,
wherein the TiO2 pigment has a coating of about 0.1 to about 5% by weight,
based on the
weight of the silanized TiO2, of at least one organosilicon compound having
the formula:
R x Si(R')4-x
wherein
R is a nonhydrolyzable aliphatic, cycloaliphatic or aromatic group
having 8-20 carbon atoms;
R' is a hydrolyzable group selected from alkoxy, halogen, acetoxy or hydroxy
or mixtures thereof; and;
x = 1 to 3.
2. A polymer matrix comprising polymer and about 50 to about 87% by weight
silanized
TiO2 pigment, based on the weight of the polymer matrix, wherein the silanized
TiO2
pigment has a coating of about 0.1 to about 5% by weight, based on the weight
of the
silanized TiO2, of an organosilicon compound comprising a mixture of (a) and
(b) wherein
(a) is at least one silane having the formula:
R x Si(R')4-x
wherein
R is a nonhydrolyzable aliphatic, cycloaliphatic or aromatic group
having 1-20 carbon atoms;
R' is a hydrolyzable group selected from alkoxy, halogen, acetoxy or
hydroxy or mixtures thereof, and
x = 1 to 3; and
(b) is at least one polysiloxane having the formula:
<IMG>
wherein
R is an organic or inorganic group;
n = 0-3; and
m .gtoreq. 2.

13
3. The composition of Claim 1 or Claim 2 wherein the polymer is polyolefin.
4. The composition of Claim 3 wherein the polyolefin is polyethylene.
5. The composition of Claim 1 or Claim 2 wherein the polymer is polyvinyl
chloride.
6. The composition of Claim 1 wherein R is aliphatic having 8-18 carbons, R'
is alkoxy
and x =1 to 3.
7. The composition of Claim 2 wherein the mixture comprises the silane
selected from
the group consisting of butyltrimethoxysilane and octyltriethoxysilane and the
siloxane is
polydimethylsiloxane.
8. The composition of Claim 3 or Claim 4 wherein the silanized pigment is
present in
the amount of about 70 to about 82% by weight and the organosilicon compound
is selected
from the group consisting of octyltriethoxysilane, nonyltriethoxysilane,
decyltriethoxysilane,
dodecyltriethoxysilane, tridecyltriethoxysilane, tetradecyltriethoxysilane,
pentadecyltriethoxysilane, hexadecyltriethoxysilane,
heptadecyltriethoxysilane,
octadecyltriethoxysilane, mixtures thereof and mixtures of
butyltrimethoxysilane and
polydimethylsiloxane and mixtures of octyltriethoxysilane and
polydimethylsiloxane.
9. The polyolefin matrix of Claim 8 wherein the polymer is a polyolefin and
(a) the polyolefin is polyethylene;
{b) the silanized TiO2 is TiO2 coated with about 0.5 to 1.5% by weight of an
octyltriethoxysilane; and
(c) the silanized TiO2 pigment is present in the amount of about 70% by
weight.
10. The polethylene matrix of Claim 9 wherein the coating comprises about 1%
by weight
of butyltrimethoxysilane and 1% by weight polydimethylsiloxane.
11. The polyethylene matrix of Claim 9 wherein the coating further comprises
1% by
weight of polydimethylsiloxane.
12. A process for enhancing processability in compounding highly loaded TiO2
in a
polymer matrix comprising the steps of:

14
(a) coating TiO2 with an organosilicon compound so that a chemical bond is
formed; and
(b) rapidly processing a high concentration of organosilicon coated TiO2 with
a
polymer in an internal mixer at increased flux time, wherein the organosilicon
compound has the formula,
R x Si(R')4-x
whezein
R is a nonhydrolyxable aliphatic, cycloaliphatic or aromatic group having 8-20
carbon atoms;
R' is a hydrolyzable group selected from alkoxy, halogen, acetoxy or hydroxy
or mixtures thereof; and
x = 1 to 3;
13. A process for enhancing processability in compounding highly loaded TiO2
in a
polymer matrix comprising the steps of:
(a) coating TiO2 with an organosilicon compound so that a chemical bond is
formed; and
(b) rapidly processing a high concentration of organosilicon coated TiO2 with
a
polymer in an internal mixer at increased flux time, wherein the organosilicon
compound comprises a mixture of (a) and (b) wherein,
(a) is at least one silane having the formula:
R x Si(R')4-x
wherein
R is a nonhydrolyzable aliphatic, cycloaliphatic or aromatic group having 1-20
carbon atoms;
R' is a hydrolyzable group selected from alkoxy, halogen, acetoxy or hydroxy
or mixtures thereof, and x = 1 to 3; and
(b) is at least one polysiloxane having the formula:
<IMG>
wherein R is an organic or inorganic group;
n = 0-3; and
m .gtoreq. 2.

15
14. The process of Claim 12 or Claim 13 wherein
(a) the polymer is polyolefin;
(b) the organosilicon compound is present in the amount of about 0.5 to about
5%
by weight; and
(c) the high concentration of the TiO2 ranges from about 50 to about 82%.
15. A process for preparing a polyethylene composition comprising polyethylene
and
coated TiO2 pigment, comprising the steps of:
(a) coating TiO2 pigment with at least one organosilicon compound having the
formula:
R x Si(R')4-x
wherein
R is a nonhydrolyzable aliphatic, cycloaliphatic or aromatic group having 8-20
carbon atoms;
R' is a hydrolyzable group selected from alkoxy, halogen, acetoxy or hydroxy
or mixtures thereof; and
x = 1 to 3
to form coated TiO2 pigment; and
(b) mixing the coated TiO2 pigment with a polyethylene matrix at a
concentration
of about 50 to about 87% by weight of coated TiO2 pigment based on the
weight of the polyethylene matrix to form a polyethylene composition
consisting essentially of polyethylene and coated TiO2 pigment.
16. The process of claim 15 wherein the organosilicon compound is hydrolyzed
and
forms a bond with the TiO2 pigment.
17. A process for preparing a concentrate of a silanized TiO2 pigment in a
polymer,
comprising the steps of:
(a) treating TiO2 pigment with a silane compound having the formula:
R x Si(R')4-x
wherein
R is a nonhydrolyzabte aliphatic, cycloaliphatic or aromatic group having 8-
20 carbon atoms;

16
R' is a hydrolyzable group selected from alkoxy, halogen, acetoxy or hydroxy
or mixtures thereof; and
x = 1 to 3
to form silanized TiO2 pigment; and
(b) mixing the silanized TiO2 pigment with a polymer resin to form a highly
loaded polymer concentrate comprising about 50 to about 87% by weight
silanized TiO2 pigment.
18. The process of claim 17 wherein the TiO2 pigment is treated with a mixture
of said
silane compound and a polysiloxane compound.
19. The process of claim 18 wherein the polysiloxane compound has the formula:
<IMG>
wherein
R is an organic or inorganic group;
n = 0-3; and
m .gtoreq. 2.
20. The process of any one of Claims 17 to 19 wherein the concentrate
comprises about
70 to 87% by weight silanized TiO2 pigment.
21. The process of any one of Claims 17 to 19 wherein the silane compound is
octyltrethoxysilane.
22. The process of any one of Claims 17 to 19, wherein in the general formula
of the
silane R is an aliphatic having 8-18 carbons, R' is methoxy, ethoxy, chloro,
hydroxy, or
mixtures thereof and x = 1 to 3.
23. The process of any one of Claims 17 to 19 wherein the polymer is selected
from the
group consisting of polyolefins, polyesters, polyvinyl chlorides and
polystyrene.
24. The process of Claim 20 wherein the polymer resin is polyethylene,
polypropylene, or
polybutylene.

17
25. The process of any one of Claims 17 to 24 wherein the silane treatment is
made in
step (a) to pigment from a slurry.
26. The process of any one of Claims 17 to 24 wherein the silane is added in
step (a) to
TiO2 pigment during drying.
27. The process of any one of Claims 17 to 24 wherein the silane is
prehydrolyzed prior
to treating the TiO2 pigment.
28. A polymer concentrate comprising:
(a) a polymer, and
(b) about 50 to 87% by weight of silanized TiO2 pigment, based on the weight
of
polymer concentrate, wherein the silanized TiO2 pigment is obtained by
treating the pigment with the reaction products of water ana a silane
compound having the formula:
R x Si(R')4-x
wherein R is a nonhydrolyzable aliphatic, cycloaliphatic or aromatic group
having 8-20 carbon atoms;
R' is a hydrolyzable group selected from alkoxy, halogen, acetoxy or hydroxy
or mixtures thereof; and
x=1 to3.
29. The polymer concentrate of Claim 28 comprising about 70 to 87% by weight
of
silanized TiO2 pigment.
30. The polymer concentrate of Claim 28 wherein the silane compound is
octyltriethoxysilane.
31. The polymer concentrate of Claim 28 wherein R is an aliphatic group having
8 to 18
carbon atoms and R' is methoxy, ethoxy, chloro, hydroxy or mixtures thereof
and x = 1 to 3.
32. The polymer concentrate of Claim 31, wherein R is an aliphatic group of 8
carbon
atoms.

18
33. The polymer concentrate of Claim 28 wherein the polymer is a polyolefin,
polyester,
polyvinyl chloride or polystyrene.
34. The polymer concentrate of Claim 33 wherein the polyolefin is polethylene,
polypropylene or polybutylene.
35. The polymer concentrate of Claim 28 wherein the TiO2 pigment is silanized
with
about 0.1 to about 5% by weight of the silane compound based on the weight of
the TiO2
pigment.
36. A process for preparing a pigmented polymer composition which comprises
preparing
a polymer concentrate as claimed in any one of Claims 28 to 35, and letting
down the
concentrate by addition of polymer to form a composition containing about 0.2
to about 20
weight percent of silanized TiO2 pigment.

Description

CA 02349030 2001-06-07
V1'O y5123192 PCT/US95102811
. TITLE
IMPROVED PROCESSIBILITY AND LACING RESISTANCE WHEN
SILA1~'1ZED PIGMENTS ARE INCORPORATED 1N POLYMERS
BACKGROL>Nn nF THE 1 NTinl~
The present invention relates to white-pigmented polymers
(particularly, polyolefins such as polyethylene) containing white pigments
treated
with an organosilicon compound to improve processibility in compounding and
improve performance properties such as lacing resistance in a polyolefin
matrix. '
Treatment of Ti02 pigment with organosilicon compounds to improvt
dispersibility in a polymer matrix is well known in the ari. For example, U.S.
Patents 4,061,503 and 4,151,154 disclose enhanced dispersibility of Ti02 in
paints
and plastic. Therein, the Ti02 is surface treated with a silane possessing at
least
two hydrolyzable groups bonded to silicon and an organic group containing a
polyalkylene oxide group.
In addition, U.S. Patent 4,810,305 discloses.a modified hydrophobic
pigment or filler containing 0.05 to 10 weight % of an organopolysiloxane,
with
improved dispers'bility in synthetic resins.
However, deficiencies in the prior ari include, but are not limited to,
(1) unacceptable processibility, i.e., dispcrsibility of Ti02, pigment in a
polymeric
matrix at slow rates; and (2) lacing , i.e., development of imperfections in a
polyolefin matrix. lacing occurs as a result of volatiles released from the
pigment
during high temperature polyolefin fabrication processes. Lacing may also be
attributable to Ti02 concentrates picking up moisture. A further disadvantage
is
that higher loadings of Ti02 pigment in a polymer concentrate result in slower
processing rates.
It has been found that the above combined disadvantages of the prior
an can be overcome by the present invention.
In accordance with one aspect of the present invention, there is provided a
highly
loaded polymer matrix comprising polymer resin and 50 to 87 % by weight
silanized TiOz
pigment, based on the weight of the polymer matrix, exhibiting enhanced
processibility, wherein the Ti02 pigment has a coating of 0.1 to 5% by weight,
based

CA 02349030 2004-04-16
2
silanized Ti02 pigment, of an organosilicon compound selected from at least
one
silane, or a mixture of at least one silane and at least one polysiloxane. It
has been
found that the silanized pigmentary Ti02 provides a unique combination of
enhanced processibility in a polymeric matrix having higher Ti02 loadings, and
improved end use performance properties such as lacing resistance in a
polyolefin
matrix at Ti02 concentrations ranging from about 0.2 to about 20 % by.weight,
based on the weight of the polyolefin matrix.
The Ti02 pigments useful in the present im~ention generally are in
the rutile or anatase crystalline form. It is commonly made by either a
chloride
process or a sulfate process. TiCl4 is oxidized to Ti02 particles in the
chloride
process. Sulfuric acid and ore containing titanium are dissolved, and the
resulting
solution goes through a series of steps to yield Ti02, in the sulfate process.
Both the
sulfate and chloride processes are described in greater detail in "Ihe Pigment
Handbook", Vol. 1, 2nd Ed., John Wiley & Sons, NY (1988), the teachings of
which
may be referred to herein. The optimum average particle size can range'
from about 0.005 to about 1 micron. The Ti02 pigments may also contain
ingredients added thereto to further improve dispersibilily characteristics or
other
properties such as durability. Thus, by way of example, but not limited
thereto, the
pigment may contain additives and/or inorganic oxides, such as aluminum,
silicon or
tin as well as triethanolamine, trimethylolpropane, phosphates, etc.
"Silanized" Ti02 is defined herein to refer to Ti02 treated with either
at least one silane, or a mixture of at least one silane and at least one
polysiloxane
(collectively referred to herein as organosilioon compounds).
Suitable silanes have the formula:
RxSi(R')4-x
wherein
R is a nonhydrolyzable aliphatic, cycloaliphatic or aromatic group
having at least 1 to about 20 carbon atoms;
R' is a hydrolyzable group such as an alkoxy, halogen, acetoxy or
hydroxy or mixtures thereof; and
x=ito3.
For example, silanes useful in carrying out the invention include
3 S octyltriethoxysilane, no~ltriethoxysilane, decyltriethoxysilane,

CA 02349030 2004-04-16
3
dodecyltriethoxysilane, tridccyltriethoxysilane, tetradecyltriethoxysilane,
pentadecyltriethoxysilane, hexaderyltriethoxysilane, heptadecyltriethoxysilane
and
octadecyltriethoxysilane. .Additional examples of silanes include, R=8-18
carbon
atoms; R' = chloro; mcthoxy, hydroxy or mixtures thereof; and x=1 to 3.
Preferred
silanes arc R = 8-18 carbon atoms; R' = ethoxy; and x =1 to 3. The R = 8-18
carbon
atoms is preferred for enhanced processibility. R' = ethoxy is preferred for
ease of
handling. Surprisingly, lower chain alkyl silanes resulted in longer
processing times.
Mixtures of silanes are contemplated equivalents. Weight content of the
silage,
based on total silanized pigmentary T i02 is typically about 0.1 to about S
weight %,
preferably about 05 to about 1S weight %. In excess of 5 weight % may be used
but no particular advantage is observed
In an alternative embodiment, a mixture of at least one s0ane with at
least one pulysiloxane is useful in carrying out the im~ention. Suitable
polysiloxanes
have the formula:
(RnSiO~m
2
wherein
r
R is organic or inorganic groups;
n = 0-3; and
m>2.
For example, polydimethylsiloxane (PDMS), vinyl phe~lmethyl terminated
dimethyl siloxanes, divinylmethyl terminated polydimethyl siloxane and the
like arc
suitable polys~7oxanes. PDMS is a preferred polysiloxane. The silane useful in
the
mixture may be the silane described above with R =1-8 carbon atoms, R' =
aikaacy
and x=1 preferred. Weight content of the silent and polysiloxane, based on
total
silanized pigmentary Ti02, is about 0.1 to about 5.0 weight %, preferably from
about 1 to 3 weight %. Especially preferred is about OS to 1 weight % silane
with
R=4 or 8 carbon atoms, R' =alkoxy, and x =1; and 1 weight % PDMS. The ratio of
silent to polysiloxane can be 1 silane:2 polysiloxane up to 2 silane:l
polys0oxane.
An especially preferred ratio is 1 silane: 1 polysiloxsne. .
The silane and polysiloxane are commercially ava0able or can be
prepared by processes known in the art such as those described in
"Organos0icon
Compounds", S. Pawlenko, et al., New York (1980), the teachings of which
may be referred to herein. Tie method of addition is not especially critical
and the Ti02 pigment may be treated with the s0ane in a number of ways. For

CA 02349030 2004-04-16
example, the silane addition can be made neat or prehydrolyzed to a dry
pigmentary
base, from a slurry, a filtration step, during drying or at a size operation
such as a
fluid ener~r mill, e.g., micronizer, or media mill as descn'bed in greater
detail in
copending application entitled "IMPROVED SLURRY PROCESS FOR
PREFAR>IVG SIILAI~IZ.ED Ti02 PIGMENTS, USING A NIF.DIA M1LL", the
teachings of which may be referred to herein, or post blending after
micronizing. For example, U.S. 3,834,924 descn'bes organosilane and pigment
dispersion mixed or blended directly in a suitable solids mixing apparatus. An
example of post blending is described in greater detail in U.S. Patents
3,915,735 and
4,141,751. The polysiloxane addition can be made in conjunction with the
silane or
post addition to the silanized pigment. The sflane addition and polysflaxane
addition is descn'bed in greater detsfl below. If water, either a liquid or
vapor
(steam), is present as a component of the process stream, hydrolysis of the
hydrolyzable groups of the silane will occur aad the silane coating wfll bond
to the
Ti02 base. Prehydrolyzing the silane is a preferred step in treating the Ti02
pigment with the silane. If the silane is added neat to the TiO2 base, then
moisture
adsorbed on the Ti02 will effect the hydrolysis, but at a lower rate than if
excess
moisture i's present. Hydrolysis of silanes is descn'bed in greater detail in
"Organofunctional Silanes" by Union Carbide (1991), the teachings of which
may be referred to herein.
Polymers which are suutable for use in the present im~ention include,
by way of example but not limited thereto, polymers of ethylenically
unsaturated
monomers including olefins such as polyethylene, polypropylene, polybutylene,
and
copolymers of ethylene with higher olefins such as alpha olefins containing 4
to 10
carbon atoms or vinyl acetate, etc,; vials such as polyvinyl chloride,
polyvinyl esters
.. such as polyvinyl acetate, polystyrene, acrylic homopolymers and
copolymers;
phenolia; alkyds; amino resins; epoxy resins, polyamides, polyurethanes;
phenoxy
resins, polysulfones; polycarbonates; polyether and chlorinated polyesters;
polyethers; acetal resins; polyimides; and polyoxyethylenes. The polymers
according
to the present imrention also include various rubbers and/or elastomers either
natural or synthetic polymers based on copolymerization; grafting, or physical
blending of various diene monomers with the above-mentioned polymers, all as
generally known in the art. Thus generally, the present im~ention is useful
for a~
such white-pigmented plastic or elastomeric compositions (collectively
referred to
herein as a white pigmented polymers) . For example, but not by way of
limitation,

CA 02349030 2001-06-07
WO 95123192 ~ PCT/US95I02811
the invention is felt to be particularly useful for polyolefins such as
polyethylene,
polypropylene, polyvinyl chloride, polyamides and polyesters.
As used herein, '~ligh loaded" Ti02 may vary widely for each
polymeric matrix but will be in a well known range for those skilled in the
art. For
example, in a polyolefin matrix, a high loaded Ti02 would be 50 or above % by
weight Ti02 pigment, based on the weight of the polyolefin matrix.
A wide variety of conventional additives may be included in the
polymers as is necessary, desirable or conventional for the intended end use.
Such
additives include, but are not limited to, antioxidants, light stabilizers,
lubricants,
thermal processing additives and the like.
Ti02 coated with organosilicon compounds can be incorporated into
a melt-fabricable polymer to form the polymer composition of this invention by
any
melt compounding technique known in the art. Generally, Ti02 and polymer resin
are brought together and then mixed in a blending operation that applies shear
to
the polymer melt. The polymer resin is usually available in the form of
powder,
granules, pellets, or cubes. Commonly, Ti02 and resin are first combined while
the
resin is in the solid state (not melted) and dry-blended in some way. This can
be
done in simple ways, such as by shaking in a bag or tumbling in a closed
container,
or in more sophisticated ways such as by using blenders having agitators or
paddles.
Ti02 and polymer resin can be brought together by co-feeding the materials to
internal mixers and allowing a screw to mix them together before the resin
reaches
the molten state. The melt blending of Ti02 and polymer resin can be done
using
known equipment, such as single-screw extruders, twin-screw extruders,
internal
mixers, and the like. Internal mixers are commonly used. The melt blending can
be
done as part of the process of forming a finished article of the composition,
as by
melt extrusion. Alternatively, the melt blending can be done in a preliminary
step,
optionally isolating the polymer composition, e.g., as cubes, followed by
forming a
finished article in a subsequent process. As one sidlled in the art will
recognize,
there are many possible variations of the technique for preparing polymer
compositions of the invention. One may, for example, first prepare a
concentrate
having high Ti02 concentration, i.e., one composition of the invention, and
then
combine the concentrate with polymer resin containing no Ti02 to obtain
another
composition of the invention.
The highly loaded polymer concentrates are made as described above
with the desirable weight % for the intended end use. For example, in
polyolefin

CA 02349030 2005-06-O1
coneenuates, about 50-87% by weight concentrate may be used to opacity. T'he
concentrate is "let down" into the polyolefin. Used herein, "let doom" refers
to a
ratio or percent of resin mixed with concentrate. Let down may be accomplished
in
a number of ways and is descn"bed iri great detail in'~ilm F.xtrusipn "
(1992),
the teachings of which tray be referred to herein. For exarrxple, in lacing
evaluation, a ~~ wt.% to 87 wt.% concentrate msy be let down to about 0.2 to
about
20 weight %n by dry mixing polyolefin and extruding at a speafic processing
temperature and casting it into a film. Pigment performance is rhea ewatuated
in an
end use application.
Whe highly loaded silanized pigmentary T~OZ exhibits outstanding
processibility in a polymeric matrix and lacing resistance when incorporated
into a .
polyolefin matrix. Additional advantages observed are increased bulk density,
lower
viscosity, excellent dispersi'bility, moisture resistance, and excellent
optical
properties such as high tint strength.
, The following examples are construed as illustrative and not limitative
of the remainder of the disclosure in arty way whatsoever. Farrel BIt >ganbury-
type
mixers (available from Farrel Corp., Aasonia, CT, USA) have been used in the
Examples. Broad range internal mixers as known in the art arc contemplated
equivalents. For exaatple, barrel Continuous Mixers (FCM) (available from
)"noel
Carp., Ansonia, Cl', USA) and twin screw extruders are equally applicable.
Bulk density is given as grams per cubic centimeter of uncompaeted
pigment. A pigment bulk density below about 0.b will result in difCcult solids
handling in polymer compounding. For rapid compounding of Ti02 and a polymer
in a Banbury-type mixer, a bulk density above about~U.6 is desirable.
Total flux time is a measure of processing time, or time to disperse, in
a Hanbury~-type mixer.
Viscosity, at 180 degrees Celsius, of product from the Banbury-type
mixer, was measured at a shear rate of S501/sec. Viscosity was measured with a
Kayeness capillary rheometer (available from Kayeness Corp., Honey Brook, PA,
USA).

CA 02349030 2001-06-07
WO 95/23192 PCT/US95/02811
7
EXAMPLES
PREPARATION OF A CONCENTRA ~ P MA~TFu~te~rCu
In the following examples, a 70 wt.% compound of a dry mix Ti02
balance polyethylene was prepared in the following manner. First, a dry mix of
Ti02/balance polyethylene was prepared via blending of 1562 grams of the Ti02
with 670 grams of polyethylene. The polyethylene used for the experiments was
a
low density polyethylene supplied by Quantum U.S.I. Chemicals--Code = NA212
(Cincinnati, OH, USA).
The dry mix of Ti02/polyethylene was added to the feed hopper of a
laboratory Farrel BR Banbury-type Mixer (chamber capacity = about 1100-about
1200 cc). The dry mix was then discharged into the Mixer. Stock pressure
equaled
56 psi, driven rotor speed = 230 rpm, cooling water = 85°F. The Mixer
was
equipped with recording equipment for batch temperature, power consumption,
ram
pressure, and heat loss.
The mixture of Ti02/polyethylene was subsequently processed until
the Ti02 dispersed into the melted resin (temperature=for example
220°F) defined
above as total flux time. The compound was then discharged from the mixer.
3000 grams of neutralized pigmentary ruble Ti02 were weighed into a
pan and sprayed with 30 grams of butyl trimethoxy silane, as supplied by Union
Carbide now Osi Specialty, Inc. (Tarrytown, NY, USA).
The treated pigment was ground in a fluid energy mill, e.g., micronizer
with superheated steam.
The micronized pigment was mixed in a Patterson-Kelley V-Blender
with 30 grams of polydimethylsiloxane, as supplied by Petrach now Huls Corp.
(Piscataway, NJ, USA).
The treated Ti02 polyethylene concentrate was prepared as described
above.
Same as Example 1 except that octyl triethoxy silane was used in place
of butyl trimethoxy silane.

CA 02349030 2001-06-07
WO 95123192 PC'T/US95102811 ~ ' .
8
EXAMP1.F ~ '
Neutralized pigmentary ruble Ti02 was treated with about 1 wt% of
each of octyl triethoxy silane and polydimethylsiloxane as for Example 1,
except that
these compounds were added at the micronizer, through existing nozzles in a
grinding chamber. The treated pigment and low density polyethylene were then
mixed and processed in a Banbury-type mixer to form a 70 wt% masterbatch, as
described above.
,4
Neutralized pigmentary ruble Ti02 was treated with about 1 wt% of
octyl triethoxy silane, by spraying, as for Example 1. There was no treatment
with
polydimethylsiloxane. The treated pigment was micronized, and used for
processing
in a Banbury-type mixer to a 70 wt% polyethylene masterbatch, as described
above.
~OMP~R_A~ EXAMPLE 51~5~
Pigmentary ruble Ti02 and low density polyethylene were mixed and
processed in a Banbury-type mixer to form a 70 wt% polyethylene masterbatch,
as
described above.
The results of the tests on the masterbatches from Examples 1-5 are
summarized in the table below.
Bulk Total
Density Flux Viscosity
Example ~ ~ccl
1 0.96 26 3675
2 1.01 26.2 3681
3 0.78 24.5 3479
4 0.97 28.2 3927
C-5 0.54 37.6 4459
2' This data demonstrated the processing advantages of organosilicon
compound treated pigments (Examples 1-4) versus a non-treated pigment
(Example C-S) in a 70 wt.% Ti02/polyethylene masterbatch. Shown in the table

CA 02349030 2001-06-07
WO 95/23192 PCT/US95102811
9
are bulk density improvements realized by the organosilicon compound
treatments,
total flux time improvement, and viscosity improvements for these materials
over
non-treated.
Dried, crushed, meshed pigmentary ruble Ti02 filter cake was
sprayed with about 1 wt. % of neat octyl triethoxy silane, as supplied by Osi.
The treated pigment was micronized and used for processing in a
Banbury-type mixer to a 70 wt. % polyethylene masterbatch, as described above.
COMPA-R_ATIVE EKAMP .F ~A
Same as Example 6 except butyl trimethoxy silane was used in place
of octyltriethoxysilane. The results of the tests on the masterbatches from
Examples 6-6A are summarized in the table below.
Bulk Total
Density Flux Viscosity
Ea-amble ~/~ cc1
6 0.97 28 3927
6A 0.77 48 3921
This data demonstrated the differences for a higher chain alkyl silane
(Example 6) versus a lower chain alkyl silane. Surprisingly, the lower chain
alkyl
silanes resulted in longer processing times. The lower chain alkyl silane
realized a
70% increase in processing time over the higher chain alkyl silane.
nn~~tmr~ i
3000 grams of pigmentary rutile Ti02 was treated with 1 weight %
(30 grams) octyltriethoxysilane via spraying. Material was processed in a
Banbury-type mixer at 70 weight % in a polyethylene masterbatch as described
above.
COMPARATIVE EXAMPLE 7A
3000 grams of pigmentary rutile Ti02 was treated with 1 weight %
(30 grams) polydimethylsiloxane (PDMS) via spraying. Material was processed in
a

CA 02349030 2001-06-07
WO 95123192 ~ ~ PCT/US95/02811
Banbury-type mixer at 70 weight % in a polyethylene masterbatch as described
above.
EXAMPLE 8
Pigmentary rutile Ti02 was treated with 1 weight %
octadecyltriethoxy silane (available from Hull) via spraying: Material was
processed
in a Banbury-type mixer at 70 weight % in a polyethylene masterbatch as
described
above.
The results of tests on the masterbatches from Examples 7, 7A and 8
are summarized in the table below.
Bulk Total
Density Flux Viscosity
Example ..>~1 -l~ ~,pl
7 0.63 30.2 2968
7A 0.59 353 3491
8 0.58 33 2746
This data demonstrated a series of post-blended higher chain alkyl
silane (Examples 7 and 8) and siloxane (Comparative Example 7A) treated
materials. For the two silane treated materials (Examples 7 and 8) treated
with a
higher chain alkyl silane, final product viscosities were nearly identical.
For the
siloxane only (Comparative Example 7A) treated material viscosity and
processing
time were higher.
EXAMPLE 9
Silanized pigment, octyltriethoxysilane, and polyester were dry
blended in a double cone blender for 5 minutes to yield a 50/50 mixture. This
mixture was added to a feed hopper of a Farrel Continuous Mixer (FCM). The
mixture of treated Ti02/polyester was subsequently processed until the treated
Ti02 dispersed into the melted resin (temperature=S50°F). Observable
flow of the
concentrate was smooth and continuous.

CA 02349030 2005-06-O1
An untreated anatase pigment, I~ronos'~ 1072 (available from Kronas,
L,everkuesen, f'xermany), was dry blended, fed and processed in the FCM as in
Fatample 9. Observable flow of the concentrate was not smooth. Continnaus flow
was not attained.
Lacing occurs as a function of pigarent volatility at specific wt 96
pigment loadings and provessing temperature. For polyethylene blurs pigmented
v~nth tita~um dioaade, 20'wt ~b ~'i~ in the film processed at temperatures of
620'°'F
a~r greater will discern readily lacibdity of the film. ~pically, materials
are rated 10
ii' they do not Iacx, and below 10 if they begin to lace.
'Iwo materials are compared in the following for lacing.
By weight, 209''0 of an octyltriethaxy silane treated TfOZ was
etimpouaded into balance palyethylene. Material was extruded on a ICillion
single
screw extr~ider through a film die at 620°F. Evaluation of the filal on
a light boy
revealed superior integrity with no thin spots ox pin-holes. Rating of
material
equaled 10. Ladag resistance was comparable to the industry atandard,'I'i-
Purem
xt-101, available from E. I. du Pont de Nemours and Company, Wilm~.ngton, DE,
><JSA.
2S By weight, 20% of a sdoxane treated pigment RCLr69, (available from
f~CM, Baltimore, MD, USA) wax compounded i~o balance polyethyleac. Material
vvas extruded an s Kiliion single screw extruder through a film die at
620°F.
Material exh~ited thin spots under a tight box. Material was rated as a 7. '
Having thus described and exemplified the imrendon with a certain
degree of particularity, it should be appreciated that the following
claims'are not to
tie so limited but are to be afforded a scope commensurate with the wording of
each
Element of the claim and equivalents thereof.