U.S. patent application number 13/752634 was filed with the patent office on 2014-07-31 for polydisperse compositions and methods for eliminating volatile organic compounds.
This patent application is currently assigned to XEROX CORPORATION. The applicant listed for this patent is XEROX CORPORATION. Invention is credited to William C. DEAN, Christopher Auguste DIRUBIO, Jeffrey C. SHELTON, Patricia A. WANG.
Application Number | 20140208977 13/752634 |
Document ID | / |
Family ID | 51031712 |
Filed Date | 2014-07-31 |
United States Patent
Application |
20140208977 |
Kind Code |
A1 |
DIRUBIO; Christopher Auguste ;
et al. |
July 31, 2014 |
POLYDISPERSE COMPOSITIONS AND METHODS FOR ELIMINATING VOLATILE
ORGANIC COMPOUNDS
Abstract
A composition that has a low volatile organic compound (VOC)
content and methods for producing compositions having a low VOC
content. The composition, such as a solid ink and/or toner release
oil composition, may include less than about 0.15% by weight VOCs
that have a sufficient vapor pressure at the operating temperature
of printing device to enter the gas phase at the operating
temperature of the printing device.
Inventors: |
DIRUBIO; Christopher Auguste;
(Webster, NY) ; DEAN; William C.; (Pittsford,
NY) ; SHELTON; Jeffrey C.; (Portland, OR) ;
WANG; Patricia A.; (Lake Oswego, OR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
XEROX CORPORATION |
Norwalk |
CT |
US |
|
|
Assignee: |
XEROX CORPORATION
Norwalk
CT
|
Family ID: |
51031712 |
Appl. No.: |
13/752634 |
Filed: |
January 29, 2013 |
Current U.S.
Class: |
106/2 |
Current CPC
Class: |
C08L 83/04 20130101;
C08G 77/045 20130101 |
Class at
Publication: |
106/2 |
International
Class: |
C09D 5/00 20060101
C09D005/00 |
Claims
1-7. (canceled)
8. A method of preparing a polydisperse oil having a low content of
volatile organic compounds (VOCs), the method comprising: flowing
polydisperse oil comprising VOCs over a surface to form a layer of
polydisperse oil, and forming a stripped polydisperse oil
substantially free of VOCs having a molecular weight less than
about 1500 g/mol by heating the layer of polydisperse oil at an
effective temperature to remove VOCs having a molecular weight less
than about 1500 g/mol.
9. The method of claim 8, wherein the polydisperse oil has a number
average molecular weight in the range of from about 800 g/mol to
about 3500 g/mol, and a polydispersity index (M.sub.w/M.sub.n) in
the range of from about 1.1 to about 2.2; and the layer of
polydisperse oil is heated at an effective temperature to remove
VOCs having a molecular weight less than about 550 g/mol to form a
stripped polydisperse oil that includes less than about 0.15% by
weight VOCs having a molecular weight less than about 550
g/mol.
10. The method of claim 9, wherein the VOCs have a vapor pressure
in the range of from about 0.01 mmHg to about 40 mmHg at 25.degree.
C.
11. The method of claim 9, wherein the polydisperse oil has a
viscosity in the range of from 10 cSt to about 40 cSt, and the
viscosity of the stripped polydisperse oil is within about 2% of
the viscosity of the polydisperse oil.
12. The method of claim 9, wherein the polydisperse oil is a solid
ink oil and the effective temperature is in the range of from about
40.degree. C. to about 120.degree. C.
13. The method of claim 8, wherein the polydisperse oil is a fuser
oil and the effective temperature is in the range of from about
140.degree. C. to about 250.degree. C.
14. The method of claim 8, wherein the surface area to volume ratio
of the layer of polydisperse oil is in the range of from about 1
cm.sup.-1 to about 10 cm.sup.-1.
15. The method of claim 8, further comprising: flowing gas over the
layer of polydisperse oil.
16. The method of claim 8, wherein heating is conducted under a
partial vacuum.
17. The method of claim 8, wherein the surface is a ramp and the
layer of polydisperse oil is formed over the surface of ramp.
18. The method of claim 9, wherein the polydisperse oil is a
polydimethylsiloxane, and the VOCs having a molecular weight less
than about 550 g/mol include linear siloxanes and cyclic
siloxanes.
19. The method of claim 18, wherein the stripped polydisperse oil
contains an amount of cyclic siloxanes having a molecular weight
less than about 550 g/mol that is at least 20 times lower than that
of the polydisperse oil, and an amount of linear siloxanes having a
molecular weight less than about 550 g/mol that is at least 20
times lower than that of the polydisperse oil.
20. The method of claim 9, wherein the stripped polydisperse oil
contains a VOC content that is at least 50 times lower than the
polydisperse oil comprising VOCs, and the mass of the stripped
polydisperse oil is within about 1% of the mass of the polydisperse
oil.
Description
TECHNICAL FIELD
[0001] This disclosure is generally directed to solid ink and toner
release oil compositions having low volatile organic compound (VOC)
emissions. More specifically, this disclosure is directed to
low-VOC emission compositions including a polydisperse oil, and
processes for making such compositions.
BACKGROUND
[0002] In xerographic and solid ink printing applications, it is
desirable to use release agent oils which are cost effective,
clear, colorless, odorless or nearly so at room temperature and at
operating temperatures, free of additives (such as acids, bases,
peroxides, heavy metals, and the like) that can interfere with the
fusing/transfer and sheet release performance of the
fusing/transfer system and associated hardware, and free of or
capable of producing minimal volatile emission compounds over the
service life of the release agent oil.
[0003] In a typical solid ink print process, a thin film of oil is
applied to the surface of a rotating metal drum, and the print
heads jet the ink onto the oiled surface of the drum. Once the
image is built on the drum, it is transferred to a media, such as a
paper or a substrate. The oil acts as a release layer and reduces
the adhesive force of the ink to the drum surface, which aids in
the transfer efficiency of the ink from the drum surface to the
media. In order to achieve high transfer efficiency and excellent
print quality, the adhesive force between the media and the ink
should be higher than the adhesive force between the ink and the
oiled drum surface. Without the oil, the drum-ink adhesion is too
high, resulting in poor transfer efficiency and poor image
quality.
[0004] Various conventional oil compositions for a printing system
have been proposed, the compositions having a wide range of
additives and constituent materials. U.S. Pat. No. 6,183,929 to
Chow et al. discloses a fuser member comprising a substrate, a
layer thereover comprising a polymer and, on the polymeric layer, a
coating of a release agent comprising a mixture of (a) an
organosilane polymer concentrate containing amino-substituted or
mercapto-substituted organosiloxane polymers, the concentrate
having a viscosity of from about 50 to about 500 cSt, and (b) a
nonfunctional organosiloxane polymer diluent having a viscosity of
from about 100 to about 2,000 cSt. U.S. Pat. No. 7,208,259 to
Badesha et al. discloses a fuser member comprising a substrate, a
layer thereover comprising a polymer, and, on the polymeric layer,
a coating of a release agent comprising a mixture of (a) an
organosiloxane polymer concentrate containing amino-substituted
organosiloxane and (b) a nonfunctional organosiloxane polymer
diluent. U.S. Pat. No. 4,029,827 to Imperial et al. discloses
polyorganosiloxanes having functional mercapto groups, which are
applied to a heated fuser member in an electrostatic reproducing
apparatus to form thereon a thermally stable, renewable,
self-cleaning layer having superior toner release properties for
electroscopic thermoplastic resin toners. The disclosures of U.S.
Pat. Nos. 6,183,929, 7,208,259, and 4,029,827 are totally
incorporated herein by reference in their entireties.
[0005] U.S. Pat. No. 4,101,686 to Strella et al. and U.S. Pat. No.
4,185,140 to Strella et al. disclose polymeric release agents
having functional groups such as carboxy, hydroxyl, epoxy, amino,
isocyanate, thioether, or mercapto groups. U.S. Pat. No. 5,157,445
to Shoji et al. discloses toner release oil having a functional
organopolysiloxane of a certain formula. U.S. Pat. No. 4,251,777 to
Martin discloses compositions containing organopolysiloxanes and
thiofunctional polysiloxanes having at least one mercapto group
which are effective as corrosion inhibitors and as release agents
for metal substrates. U.S. Pat. No. 5,512,409 to Henry et al.
teaches a method of fusing thermoplastic resin toner images to a
substrate using amino functional silicone oil over a
hydrofluoroelastomer fuser member. U.S. Pat. No. 5,516,361 to Chow
et al. teaches a fusing member having a thermally stable FKM
hydrofluoroelastomer surface and having a polyorgano T-type amino
functional oil release agent. The disclosures of U.S. Pat. Nos.
4,101,686, 4,185,140, 5,157,445, 4,251,777, 5,512,409, 5,516,361,
and 4,101,686 are totally incorporated herein by reference in their
entireties.
[0006] These conventional release layer oils, such as typical
silicone oils, emit volatile organic compounds (VOCs) when heated
by the drum surface. For example, thermal degradation of release
agents may result in the generation of volatile byproducts
including, for example, formaldehyde (CH.sub.2O), formic acid
(HCO.sub.2H), carbon dioxide (CO.sub.2), carbon monoxide (CO),
hydrogen (H.sub.2), methanol (CH.sub.3OH), ammonia (NH.sub.3),
hydrogen sulfide (H.sub.2S), trifluoropropionaldehyde
(CF.sub.3CH.sub.2CHO), cyclic siloxanes, linear siloxanes, and the
like. The abatement system of the solid ink printer pulls air,
dust, particles, and volatile chemicals out of the printer cavity
and into the environment with a fan, thereby releasing the VOCs
into the environment. Many VOCs are hazardous to human health and
harmful to the environment. In order to meet increasingly stringent
environmental certifications (such as Blue Angel certification) and
governmental regulations (such as EPEAT and EcoLogo), the VOCs
emitted by the oil and exhausted into the environment should be
reduced significantly.
[0007] As a result, there exists a need to develop an oil
composition that exhibits low VOC emissions that can be produced
without chemically altering or degrading the oil, while minimizing
the change in viscosity of the oil.
SUMMARY
[0008] According to aspects illustrated herein, there is provided a
composition including a polydisperse polymer having a viscosity in
the range of from about 10 cSt to about 700 cSt, where the
polydisperse polymer emits less than about 0.5 PPM (methanol
equivalent) volatile organic compounds when heated to a temperature
of from about 50.degree. C. to about 250.degree. C., and where the
polydisperse polymer includes less than about 0.15% by weight
volatile organic compounds (VOCs) having a molecular weight less
than about 1500 g/mol.
[0009] In some embodiments, the present disclosure relates to a
method of preparing a polydisperse oil having a low content of
volatile organic compounds (VOCs), the method including flowing
polydisperse oil comprising VOCs over a surface to form a layer of
polydisperse oil, and forming a stripped polydisperse oil
substantially free of VOCs having a molecular weight less than
about 1500 g/mol by heating the layer of polydisperse oil at an
effective temperature to remove VOCs having a molecular weight less
than about 1500 g/mol. In embodiments, the methods of the present
disclosure may very selectively strip only the most volatile
components (such as the VOCs) of the polydisperse polymer or
composition, such as a polydisperse oil, without significantly
increasing its viscosity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a graphical representation of the impact of oil
viscosity on molecular weight distributions and VOC emissions.
[0011] FIG. 2 is a graphical representation of the number average
molecular weight (M.sub.n) distribution of the polydisperse oil
(diluent) and a polydisperse oil (diluent)/functionalized
polydisperse oil blend as a function of diluent viscosity.
[0012] FIG. 3 is a graphical representation of the polydispersity
index (M.sub.w/M.sub.n) of the polydisperse oil (diluent) and the
blend as a function of diluent viscosity.
[0013] FIG. 4 is a graphical representation of siloxane volatility
as a function of molecular weight.
[0014] FIG. 5 is a graphical representation of the effect of
aggressive, low-precision stripping methods on oil molecular weight
distribution.
[0015] FIG. 6 is a graphical illustration of the molecular weight
distribution following a high precision stripping of low molecular
weight components.
[0016] FIG. 7 is an illustration of one exemplary helical ramp over
which a polydisperse oil may be flowed to remove VOCs.
[0017] FIG. 8 is an illustration of a print process incorporating a
release oil.
[0018] FIG. 9 is a graphical representation of the VOC emissions
over time of a polydisperse oil composition during the selective,
high precision VOC stripping process.
EMBODIMENTS
[0019] In this specification and the claims that follow, singular
forms such as "a," "an," and "the" include plural forms unless the
content clearly dictates otherwise. All ranges disclosed herein
include, unless specifically indicated, all endpoints and
intermediate values. The term "at least one" refers, for example,
to instances in which one of the subsequently described
circumstances occurs, and to instances in which more than one of
the subsequently described circumstances occurs.
[0020] As used herein, the modifier, "about," used in connection
with a quantity is inclusive of the stated value and has the
meaning dictated by the context (for example, it includes at least
the degree of error associated with the measurement of the
particular quantity). When used in the context of a range, the
modifier, "about," should also be considered as disclosing the
range defined by the absolute values of the two endpoints. For
example, the range, "from about 2 to about 4," also discloses the
range, "from 2 to 4."
[0021] The term "polydisperse" refers, for example, to a polymer,
composition or oil comprising polymer molecules containing
individual polymerized repeating units where the degree of
polymerisation (DP) or chain length varies such that the percentage
of the number of molecules in the composition or oil of a
particular molecular weight forms a distribution, such as a
Gaussian distribution. The distribution may also be bimodal,
trimodal or tetramodal where more than one polymer composition
having a particular average molecular weight is blended together to
form the polydisperse composition or oil. The individual
polymerized molecules making up the distribution may have differing
molecular weights that vary by the molecular weight of the
repeating unit. For example, the distribution of individual
polymerized molecules may be made up of polymers that have
molecular weights that differ by the mass of one of the repeat
unit(s).
[0022] The term "functionalized" refers, as used in the expression
functionalized polydisperse oil or composition component
(hereinafter "functionalized polydisperse oil"), for example, to a
polydisperse oil having functional groups pendant from at least
some of the polymer molecules therein. For instance,
"functionalized polydisperse oil" may refer to polydisperse oils
having functional groups that are capable of interacting with the
fuser member or transfer member surface to form a thermally-stable
barrier to toner or ink, which adheres to the metal, glass, or
other substrate of the fuser/transfer member and provides a thin
coating which has excellent release properties for the toners or
inks used in the printing process. "Functionalized polydisperse
oil" further refers to polydisperse oils having functional groups
that chemically react with fillers present on the surface of a
fuser/transfer member, so as to reduce the surface energy of the
fillers so as to provide better release of toner particles or ink
from the surface of the fuser/transfer member. If the surface
energy is not reduced, the toner particles or ink will tend to
adhere to the fuser/transfer roll surface or to filler particles on
the surface of the fuser/transfer roll, which will result in copy
quality defects. The term "functional group" refers, for example,
to a group of atoms arranged in a way that determines the chemical
properties of the group and the molecule to which it is attached.
Examples of functional groups include carboxy, hydroxyl, epoxy,
amino, isocyanate, thioether, mercapto, and the like, and
combinations thereof.
[0023] As used herein, the term "volatile organic compound" or VOC
refers, for example, to an organic compound having a sufficient
vapor pressure at a predetermined temperature such that the organic
compound will enter the gas phase at the predetermined temperature.
In some embodiments, such a predetermined temperature may be in the
range of from about 40.degree. C. to about 250.degree. C. In
embodiments, such a predetermined temperature may be in the range
of from about 40.degree. C. to about 80.degree. C. In other
embodiments, such a predetermined temperature may be in the range
of from about 140.degree. C. to about 210.degree. C. In some
embodiments, a VOC may be an organic compound that leaves the
unstripped bulk fluid (or composition, such as a toner or ink
release oil composition, containing a polydisperse oil), at the
predetermined temperature, and enters the gas phase (such as by an
evaporation process and/or a volatilization process) to an extent
that it exists in the gas phase (at the predetermined temperature)
at concentration of greater than about 1.5 PPM (methanol
equivalent) as measured using a Flame Ionization Detector (FID), or
exist in the gas phase at concentration of from about 1.5 PPM to
about 100 PPM (methanol equivalent) as measured using a Flame
Ionization Detector (FID). In some embodiments, a VOC may be an
organic compound that leaves the unstripped bulk fluid (or
composition, such as a toner or ink release oil composition,
containing a polydisperse oil), at the predetermined temperature,
and enters the gas phase (such as by an evaporation process and/or
a volatilization process) to an extent that it exists in the gas
phase at concentration of greater than about 5 PPM (methanol
equivalent) as measured using a Flame Ionization Detector (FID), or
exist in the gas phase (at the predetermined temperature) at
concentration of from about 5 PPM to about 50 PPM (methanol
equivalent) as measured using a Flame Ionization Detector
(FID).
[0024] The current disclosure provides a polydisperse polymer
and/or polydisperse polymer composition (hereinafter collectively
referred to as a "composition" unless expressly noted otherwise),
such as a toner or ink release oil composition, containing a
polydisperse oil. In embodiments, the composition may comprise a
single oil, or may comprise a blend of multiple oils, such as a
blend of two or more oils. In embodiments, a composition, such as a
toner or ink release oil composition, may contain a polydisperse
polymer or a polydisperse oil blend comprising a polydisperse oil
(diluent) and a functionalized polydisperse oil.
[0025] The viscosity and volatility (and, thus, VOC emissions) of
compositions of polydisperse oils, such as a silicone oil
compositions, depend on a number of factors including the molecular
weight distribution of the polymer molecules in the oil. For
example, with respect to polydisperse polymers or compositions,
such as polydisperse oils, with a large molecular weight
distribution, the low molecular weight molecules are the most
volatile because they are bound (via intermolecular forces) more
weakly to the other molecules in the oil. As a result, these low
molecular weight molecules make the greatest contribution to the
VOCs emitted by the heated oil.
[0026] VOC emissions are a function of temperature--that is to say,
as temperature increases, the molecular weight threshold for
volatility also increases. In embodiments (such as for solid ink
jet oils, where the drum may be operated at a temperature of, for
example, less than about 80.degree. C., such as from about
40.degree. C. to about 60.degree. C., or from about 50.degree. C.
to about 55.degree. C.), the low molecular weight molecules that
may be removed, such as by evaporation and/or volatilization, by
the methods of the present disclosure may be molecules with a
molecular weight of, for example, less than about 700 g/mol, such
as less than about 550 g/mol, or less than about 450 g/mol.
[0027] In some embodiments (such as for fuser oils), the oils may
be heated at a higher operating temperature, such as from about
140.degree. C. to about 210.degree. C., or from about 150.degree.
C. to about 200.degree. C. At such temperatures, the low molecular
weight molecules that may be removed, such as by evaporation and/or
volatilization, may be molecules with a molecular weight of, for
example, less than about 2000 g/mol, such as less than about 1500
g/mol, or less than about 1000 g/mol, or less than about 800
g/mol.
[0028] Increasing the molecular weight of the molecules generally
increases the extent of intermolecular forces experienced by
polymer molecules, which thereby increases the oil viscosity and
decreases the volatility. However, for solid ink jet applications,
the duplex ink transfer efficiency decreases rapidly as oil
viscosity increases. Thus, while increasing oil viscosity until the
low molecular weight fraction becomes negligible should reduce VOC
emissions, high viscosity oils exhibit poor transfer efficiency,
particularly to the second side of a media during duplex
printing.
[0029] For fuser applications, while the viscosity of the oil may
be higher, it is desirable to minimize the change in the viscosity
of the oil because particular applications and imaging devices may
require use of an oil having a particular viscosity, and increasing
the viscosity of the oil may render the oil less suitable for the
intended application or imaging device.
[0030] The methods of the present disclosure very selectively
strip, such as by removing due to evaporation and/or
volatilization, only the most volatile components (such as the
VOCs) of the polydisperse polymer or composition, such as a
polydisperse oil, without significantly increasing its viscosity,
thereby avoiding the problems associated with high viscosity
compositions. In the methods of the present disclosure, the
selective stripping may be achieved by stirring and heating a thin
pool of the polydisperse polymer or composition, such as a
polydisperse oil, at relatively low temperatures under a constant
air flow of several cubic feet per minute, which results in a low
volatility polydisperse polymer or composition, such as a low
volatility polydisperse oil, with essentially unchanged viscosity
with respect to the original polydisperse polymer or composition,
such as a polydisperse oil, or the original components of any blend
of such components.
[0031] Before stripping, the VOCs in a composition containing VOCs
may volatilize when the composition containing VOCs is heated to a
predetermined temperature, such that the VOCs are present in the
gas phase in a concentration of greater than about 1.5 PPM
(methanol equivalent), such as greater than about 5 PPM, or greater
than about 10 PPM, as measured using a Flame Ionization Detector
(FID).
[0032] In embodiments, the compositions of the present disclosure
are compositions in which a majority of most of the volatile
components has been removed, such as polymer compositions that have
been selectively stripped of the VOCs. Accordingly, when the
compositions and/or polymer compositions according to the current
disclosure are heated to a predetermined temperature (within the
ranges discussed above), the VOC emissions may be lower, such that
the VOCs are only present in the gas phase and/or vapor phase
(collectively hereinafter referred to as the vapor phase) in a
concentration of less than 0.5 PPM (methanol equivalent), such as
in a concentration of from 0.001 PPM to about 0.5 PPM (methanol
equivalent), or a concentration of from 0.01 PPM to about 0.1 PPM
(methanol equivalent). In some embodiments, when the compositions
and/or polymer compositions according to the current disclosure are
heated to a predetermined temperature (within the ranges discussed
above), the VOC emissions may be lower, such that the VOCs are only
present in the gas phase and/or vapor phase (collectively
hereinafter referred to as the vapor phase) in a concentration of
less than about 0.1 PPM, or less than about 0.08 PPM, or less than
about 0.01 PPM, or less than about 0.001 PPM, as measured using
FID. In embodiments, the VOC emissions (methanol equivalent) as
measured using a Flame Ionization Detector (FID) of a polydisperse
oil or functionalized polydisperse oil stripped according to the
methods of the current disclosure may be 10 times less than that of
the polydisperse oil or the functionalized polydisperse oil prior
to stripping, such as about 15 times less, or about 50 times less,
or about 70 times less, or about 80 times less.
[0033] Polydisperse Oil Composition (Solid Ink Jet Oils)
[0034] In embodiments (such as for solid ink jet oils), the
polydisperse polymer or composition may comprise one or more
polydisperse oils, such as a first, second, third and/or fourth
polydisperse oil each having a viscosity less than about 40 cSt,
such as less than about 30 cSt, or less than about 25 cSt. In
embodiments, such polydisperse oil(s) may have a viscosity greater
than about 5 cSt, such as greater than about 10 cSt, or greater
than about 15 cSt. In embodiments, the polydisperse oil may include
less than about 0.15% by weight VOCs, such as less than about 0.1%
by weight VOCs, or less than about 0.01% by weight VOCs, or less
than about 0.001% by weight VOCs, having a molecular weight less
than about 700 g/mol, such as less than about 550 g/mol, or less
than about 450 g/mol.
[0035] In embodiments, the polydisperse oil may be a blended oil
comprising a polydisperse oil (diluent) and a functionalized
polydisperse oil. The polydisperse oil (diluent) component of the
blend for a solid ink jet oil may comprise one or more polydisperse
oils, such as a first, second, third, and/or fourth polydisperse
oil each having a viscosity less than about 40 cSt, such as less
than about 30 cSt, or less than about 25 cSt. The functionalized
polydisperse oil component of the blend may have a viscosity much
higher than that of the first polydisperse components in the blend.
For example, the functionalized polydisperse oil may have a
viscosity in the range of from about 200 cSt to about 1200 cSt,
such as in the range of from about 400 cSt to about 1000 cSt, or in
the range of from about 500 cSt to about 800 cSt.
[0036] In embodiments, the polydisperse oil blend may be an ink
release oil composition that may include less than about 0.15% by
weight VOCs, such as less than about 0.1% by weight VOCs, or less
than about 0.01% by weight VOCs, or less than about 0.001% by
weight VOCs, having a molecular weight less than about 700 g/mol,
such as less than about 550 g/mol, or less than about 450 g/mol. In
embodiments, each of the polydisperse components of the blend
includes less than about 0.15% by weight VOCs, such as less than
about 0.1% by weight VOCs, or less than about 0.01% by weight VOCs,
or less than about 0.001% by weight VOCs, having a molecular weight
less than about 700 g/mol, such as less than about 550 g/mol, or
less than about 450 g/mol.
[0037] In embodiments, the polydisperse oil blend may have a
content of VOCs having a molecular weight less than about 700
g/mol, such as less than about 550 g/mol, or less than about 450
g/mol, that is at least 10 times less than that of the polydisperse
oil or the functionalized polydisperse oil prior to stripping, such
as about 15 times less, or about 50 times less, or about 70 times
less, or about 80 times less.
[0038] In embodiments, the polydisperse oil blend, which may be an
ink release oil composition, comprises a functionalized
polydisperse oil having a viscosity in the range of from about 200
cSt to about 1200 cSt, such that the blend has a viscosity less
than about 40 cSt, such as less than about 30 cSt, or less than
about 20 cSt, and includes less than about 0.15% by weight VOCs
having a molecular weight less than about 550 g/mol. In
embodiments, the polydisperse oil blend has a viscosity greater
than about 10 cSt and less than about 40 cSt, such as less than
about 30 cSt, or less than about 20 cSt, and includes less than
about 0.15% by weight VOCs, such as less than about 0.1% by weight
VOCs, or less than about 0.01% by weight VOCs, or less than about
0.001% by weight VOCs, having a molecular weight less than about
700 g/mol, such as less than about 550 g/mol, or less than about
450 g/mol.
[0039] The distribution of the molecular weights of the
polydisperse oil (diluent) when plotted against the population of
individual molecules having the respective molecular weight may be
a wide or narrow distribution where the difference between the
molecular weight at the lower end of the distribution and the upper
end of the distribution is in the range of from about 500 g/mol to
about 5000 g/mol, such as where the difference between the
molecular weight at the lower end of the distribution and the upper
end of the distribution is in the range of from about 800 g/mol to
about 3500 g/mol.
[0040] In embodiments, before the methods of the present disclosure
are used to remove the low molecular weight fraction, the weight
percentage of VOCs having a molecular weight at the lower end of
the distribution in the range of from about 30 g/mol to about 700
g/mol, such as in the range of from about 50 g/mol to about 550
g/mol, or in the range of from about 70 g/mol to about 450 g/mol
may be from about 0.01% to about 3%, such as from about 0.015% to
about 1%. Before the methods of the present disclosure are used to
remove the low molecular weight fraction (including VOCs having a
molecular weight less than about 700 g/mol, such as less than about
550 g/mol, or less than about 450 g/mol), the logarithm of the
molecular weight distribution of the first polydisperse oil may be
substantially Gaussian.
[0041] In embodiments, after the methods of the present disclosure
are used to remove the low molecular weight fraction, substantially
all of the VOCs, such as at least 90% by weight (relative to the
initial weight amount of VOCs that were present), or at least 98%
by weight, or at least 99.9% by weight of the VOCs having a
molecular weight less than about 700 g/mol, such as less than about
550 g/mol, or less than about 450 g/mol, have been removed. After
the aforementioned VOCs are removed, the lowest substantially
populated molecular weight (such as greater than 0.001% abundance,
or greater than 0.02% abundance relative to the population of the
entire molecular weight distribution) at the lower end of the
distribution may be in the range of from about 450 g/mol to about
800 g/mol, such as in the range of from about 500 g/mol to about
750 g/mol, or in the range of from about 550 g/mol to about 700
g/mol. After the methods of the present disclosure are used to
remove the low molecular weight fraction, a plot of the
distribution of the first polydisperse oil departs from a
substantially Gaussian distribution at low molecular weights
because of the removal of the lower molecular weight molecules of
the distribution (see the molecular weight distributions plotted in
FIGS. 1 and 5, and compare with the molecular weight distributions
plotted in FIG. 6).
[0042] In embodiments, the viscosity of the polydisperse oil, which
may be a solid ink jet release oil composition, before the methods
of the present disclosure are used to remove the low molecular
weight fraction is within about 4%, such as within a viscosity of
about 1%, or a viscosity of within about 0.1%, of the viscosity of
the polydisperse oil after the methods of the present disclosure
have been used to remove the low molecular weight fraction
(including VOCs having a molecular weight less than about 700
g/mol, such as less than about 550 g/mol, or less than about 450
g/mol).
[0043] The upper end of the distribution may remain the same before
and after methods of the present disclosure are used to remove the
low molecular weight fraction and may be in the range of from about
1000 g/mol to about 50,000 g/mol, such as in the range of from
about 1500 g/mol to about 4000 g/mol, or in the range of from about
2000 g/mol to about 3000 g/mol.
[0044] In embodiments, a polydisperse oil of this disclosure may be
an unsubstituted organopolysiloxane such as, for example,
polydimethylsiloxane (PDMS), diphenylpolysiloxane, or
phenylmethylsiloxane. The term "unsubstituted" refers, for example,
to oils that do not have functional groups pendant from the polymer
molecules therein.
[0045] In embodiments, the polydisperse oil has a polydispersity
index in the range of from about 1.1 to about 4, such as from about
1.5 to about 2.4.
[0046] In embodiments where the polydisperse oil composition is a
blended oil comprising a polydisperse oil (diluent) and a
functionalized polydisperse oil, the polydisperse oil (diluent)
component may have a polydispersity index (M.sub.w/M.sub.n) in the
range of from about 1.05 to about 4, such as in the range of from
about 1.1 to about 3, or in the range of from about 1.2 to about
2.
[0047] The functionalized polydisperse oil may have functional
groups pendant from at least some of the polymer molecules therein.
The functional groups may be, for example, carboxy, hydroxyl,
epoxy, amino, isocyanate, thioether, mercapto, carbinol, methacryl,
phenol, and the like.
[0048] The molecular weight of the functionalized polydisperse oil
should be sufficient to achieve a high viscosity functionalized
polydisperse oil (relative to the viscosity of the polydisperse oil
diluent). In this regard, the molecular weight of the
functionalized polydisperse oil to be used in the blended
compositions according to the present disclosure may ultimately
depend on how the polymer is functionalized and the specific
identity of the functional groups that are present on the polymer
chains. In embodiments, the average molecular weight (and
optionally the polydisperity index) of the functionalized
polydisperse oil may be selected such that the functionalized
polydisperse oil possesses a viscosity in the range of from about
200 cSt to about 1200 cSt. For example, the average molecular
weight (and optionally the polydispersity index) of the
functionalized polydisperse oil may be in a range that is
sufficient to achieve a viscosity in the range of from about 200
cSt to about 1200 cSt, such as a number average molecular weight
that is sufficient to achieve a viscosity in the range of from
about 200 cSt to about 1200 cSt, or a viscosity in the range of
from about 400 cSt to about 1000 cSt, or a viscosity in the range
of from about 500 cSt to about 800 cSt. In embodiments, such a
functionalized polydisperse oil with the above-mentioned
viscosities may have a polydispersity index (M.sub.w/M.sub.n) of
from about 1.1 to about 6, such as about 1.2 to about 4.
[0049] In embodiments, the functionalized polydisperse oil may be
prepared by any suitable method, such as by reacting
amino-functionalized polydimethylsiloxanes.
[0050] An exemplary method for making an amino functionalized
polydimethylsiloxane fuser or ink jet transfer member oil may
include making an amine-containing polydimethylsiloxane concentrate
and subsequently diluting with nonfunctional polyorganosiloxane oil
to provide a mixture with a distribution of amines in a large group
of siloxanes. In making the concentrate, a broader distribution of
the amine functionality mono-, di-, and tri-amino may be obtained.
In a typical reaction, an end blocker, amino siloxane, catalyst,
and octamethyltetrasiloxane are reacted in a vessel at elevated
temperature (of from about 100 to about 210.degree. C., or from
about 145 to about 185.degree. C.) for a desired time (of from
about 2 to about 15 hours, or from about 5 to about 10 hours).
During this time period, the ring opening and bond reformation
occurs, resulting in random distribution of amine functionality on
the polydimethylsiloxane chains. The residual catalyst is
deactivated. This is generally followed by final removal of the
volatiles under heat (for example, a temperature from about 175 to
about 250.degree. C., or from about 195 to about 220.degree. C.)
and pressure (for example, of from about 0.5 to about 5 torr, or
from about 1 to about 2 torr). In embodiments, the resulting
reaction product is then diluted with non-functional
polydimethylsiloxane for use as fuser or solid ink jet oil. The
amount and viscosity of the non-functional polydimethylsiloxane
depends on what is required for the final oil.
[0051] Polydisperse Oil/Functionalized Polydisperse Oil Blend
(Solid Ink Jet Oils)
[0052] In embodiments, the polydisperse oil (diluent) and the
functionalized polydisperse oil are combined to produce a blend.
Blending may proceed according to any suitable process.
[0053] For example, for solid ink jet oils, a polydisperse oil
(diluent) comprising less than about 0.15% by weight VOCs having a
molecular weight less than about 550 g/mol may be blended with a
functionalized polydisperse oil to produce a blend including less
than about 0.15% by weight VOCs having a molecular weight less than
about 550 g/mol. Alternatively, in embodiments, a polydisperse oil
(diluent) including more than about 0.15% by weight VOCs having a
molecular weight less than about 550 g/mol may be blended with a
functionalized polydisperse oil to produce a blend including more
than 0.15% by weight VOCs. Such blended compositions comprising
VOCs may then be subjected to the precision stripping processes of
the present disclosure to selectively strip the most volatile
components of the oil (for example, those components having a
molecular weight of less than about 550 g/mol), reducing the
content of those most volatile components of the oil without
significantly increasing the oil viscosity. After being subjected
to the stripping processes of the present disclosure, such blends
may have the VOC content reduced such that the blends include no
more than about 0.1% by weight VOCs having a molecular weight less
than about 550 g/mol, or no more than about 0.001% by weight VOCs
having a molecular weight less than about 550 g/mol.
[0054] In embodiments, the polydisperse oil (diluent) may have a
viscosity less than about 30 cSt, such as from about 10 cSt to
about 20 cSt, and the functionalized polydisperse oil may have a
viscosity in the range of from about 200 cSt to about 1200 cSt,
such as from about 400 cSt to about 800 cSt. The polydisperse oil
(diluent) and the functionalized polydisperse oil are present in
the blend in relative amounts in an effective ratio to achieve a
desired viscosity. For example, in embodiments, the polydisperse
oil component may account for about 80-95% of the blend, and the
functionalized polydisperse oil component may account for about
5-20% of the blend. The resulting blend of the polydisperse oil
(diluent) and the functionalized polydisperse oil may have a
viscosity of less than about 40 cSt, such as from about 10 to about
30 cSt, or from about 15 cSt to about 28 cSt.
[0055] In embodiments, a viscosity of less than 30 cSt may allow
for high transfer efficiency and excellent print quality in the
solid ink transfix print process shown in FIG. 8. Viscosity is
strongly dependent on the mean molecular weight of the oil. FIG. 1
is a graphical representation of the molecular weight distribution
for oils of varying viscosities, illustrating the relative fraction
of VOCs. Higher viscosity oils comprise fewer VOCs having a
molecular weight less than about 550 g/mol, and increasing oil
viscosity until the low molecular weight fraction becomes
negligible may reduce VOC emissions. However, while compositions
featuring increased oil viscosity may produce lower VOC emissions,
high viscosity oils--having a viscosity above, for example, about
30 cSt--yield objectionable print quality defects, including poor
transfer efficiency to the second side of the printing media during
duplex printing in the solid ink transfix print process.
[0056] In embodiments, the blend of the polydisperse oil (diluent)
and the functionalized polydisperse oil has a number average
molecular weight in the range of from about 1000 g/mol to about
4000 g/mol, such as from about 1500 to about 2500, or from 1700 to
about 2400 g/mol, or from about 1800 to about 2300 g/mol. The blend
of the polydisperse oil (diluent) and the functionalized
polydisperse oil may have a polydispersity index (M.sub.w/M.sub.n)
in the range of from about 1.1 to about 4, such as from about 1.5
to about 2.4.
[0057] FIG. 2 presents a graphical representation of the number
average molecular weight (M.sub.n) distribution of the polydisperse
oil (diluent) and the blend as a function of diluent viscosity.
FIG. 3 presents a graphical representation of the polydispersity
index (M.sub.w/M.sub.n) of the polydisperse oil (diluent) and the
blend as a function of diluent viscosity.
[0058] Polydisperse Oil Composition (Fuser Oils)
[0059] In embodiments (such as for fuser oils), the polydisperse
polymer or composition may comprise one or more polydisperse oils,
such as a first, second, third, and/or fourth polydisperse oil,
each having a viscosity of from about 75 cSt to about 1500 cSt,
such as from about 100 cSt to about 1000 cSt, or from about 150 cSt
to about 700 cSt. In embodiments, the polydisperse oil may include
less than about 0.15% by weight VOCs, such as less than about 0.1%
by weight VOCs, or less than about 0.01% by weight VOCs, or less
than about 0.001% by weight VOCs, having a molecular weight less
than about 2000 g/mol, such as less than about 1500 g/mol, or less
than about 1000 g/mol, or less than about 800 g/mol.
[0060] In some high viscosity embodiments (such as for oils in
which the viscosity is in the range of from about 700 cSt to about
1500 cSt, such as from about 1000 cSt to about 1300 cSt), the upper
end of the molecular weight distribution may remain the same before
and after methods of the present disclosure are used to remove the
low molecular weight fraction and may be in the range of from about
20,000 g/mol to about 100,000 g/mol, such as an upper end of the
molecular weight distribution in the range of from about 30,000
g/mol to about 60,000 g/mol, or an upper end of the molecular
weight distribution in the range of from about 40,000 g/mol to
about 50,000 g/mol.
[0061] In embodiments, the polydisperse oil may be a blended oil
comprising a first polydisperse oil (diluent) and a functionalized
polydisperse oil. The polydisperse oil component of the blend for a
fuser oil may comprise one or more polydisperse oils, such as a
first, second, third, and/or fourth polydisperse oil, each having a
viscosity of from about 100 cSt to about 190 cSt, such as from
about 125 cSt to about 180 cSt, or from about 150 to about 175 cSt.
The functionalized polydisperse oil component of the blend may have
a viscosity higher than that of the first polydisperse components
in the blend. For example, the functionalized polydisperse oil may
have a viscosity in the range of from about 200 cSt to about 1200
cSt, such as in the range of from about 400 cSt to about 1000 cSt,
or in the range of from about 500 cSt to about 800 cSt.
[0062] In embodiments, the polydisperse oil blend may be a toner
release composition that may include less than about 0.15% by
weight VOCs, such as less than about 0.1% by weight VOCs, or less
than about 0.01% by weight VOCs, or less than about 0.001% by
weight VOCs, having a molecular weight less than about 2000 g/mol,
such as less than about 1500 g/mol, or less than about 1000 g/mol,
or less than about 800 g/mol. In embodiments, each of the
polydisperse components of the blend includes less than about 0.15%
by weight VOCs, such as less than about 0.1% by weight VOCs, or
less than about 0.01% by weight VOCs, or less than about 0.001% by
weight VOCs, having a molecular weight less than about 2000 g/mol,
such as less than about 1500 g/mol, or less than about 1000 g/mol,
or less than about 800 g/mol.
[0063] In embodiments, the polydisperse oil blend may have a
content of VOCs having a molecular weight less than 2000 g/mol,
such as less than about 1500 g/mol, or less than about 1000 g/mol,
or less than about 800 g/mol, that is at least 10 times less than
that of the polydisperse oil or the functionalized polydisperse oil
prior to stripping, such as about 15 times less, or about 50 times
less, or about 70 times less, or about 80 times less.
[0064] In embodiments, the polydisperse oil blend, which may be a
toner release oil composition, comprises a functionalized
polydisperse oil having a viscosity in the range of from about 200
cSt to about 1200 cSt, such that the blend has a viscosity less
than about 75 cSt to about 1500 cSt, such as from about 100 cSt to
about 1000 cSt, or from about 150 cSt to about 700 cSt, and
includes less than about 0.15% by weight VOCs, such as less than
about 0.1% by weight VOCs, or less than about 0.01% by weight VOCs,
or less than about 0.001% by weight VOCs, having a molecular weight
less than about 2000 g/mol, such as less than about 1500 g/mol, or
less than about 1000 g/mol, or less than about 800 g/mol.
[0065] The distribution of the molecular weights of the first
polydisperse oil when plotted against the population of individual
molecules having the respective molecular weight may be a wide or
narrow distribution where the difference between the molecular
weight at the lower end of the distribution and the upper end of
the distribution is in the range of from about 500 g/mol to about
50,000 g/mol, such as where the difference between the molecular
weight at the lower end of the distribution and the upper end of
the distribution is in the range of from about 800 g/mol to about
3500 g/mol.
[0066] In embodiments, before the methods of the present disclosure
are used to remove the low molecular weight fraction, the weight
percentage of VOCs having a molecular weight at the lower end of
the distribution in the range of from about 30 g/mol to about 2500
g/mol, such as in the range of from about 400 g/mol to about 2000
g/mol, or in the range of from about 600 g/mol to about 1500 g/mol
may be from about 0.01% to about 3%, such as from about 0.015% to
about 1%. Before the methods of the present disclosure are used to
remove the low molecular weight fraction (including VOCs having a
molecular weight less than about 2000 g/mol, such as less than
about 1500 g/mol, or less than about 1000 g/mol, or less than about
800 g/mol), the logarithm of the molecular weight distribution of
the first polydisperse oil may be substantially Gaussian.
[0067] In embodiments, after the methods of the present disclosure
are used to remove the low molecular weight fraction, substantially
all of the VOCs, such as at least 90% by weight (relative to the
initial weight amount of VOCs that were present), or at least 98%
by weight, or at least 99.9% by weight of the VOCs having a
molecular weight less than about 2000 g/mol, such as less than
about 1500 g/mol, or less than about 1000 g/mol, or less than about
800 g/mol, have been removed. After the aforementioned VOCs are
removed, the lowest substantially populated molecular weight (such
as greater than 0.001% abundance, or greater than 0.02% abundance
relative to the population of the entire molecular weight
distribution) at the lower end of the distribution may be in the
range of from about 600 g/mol to about 3500 g/mol, such as in the
range of from about 650 g/mol to about 2000 g/mol, or in the range
of from about 800 g/mol to about 1500 g/mol. After the methods of
the present disclosure are used to remove the low molecular weight
fraction, a plot of the distribution of the first polydisperse oil
departs from a substantially Gaussian distribution because of the
removal of the lower molecular weight molecules of the
distribution.
[0068] In embodiments, the viscosity of the polydisperse oil blend,
which may be a toner release oil composition, before the methods of
the present disclosure are used to remove the low molecular weight
fraction is within about 4%, such as within a viscosity of about
1%, or a viscosity of within about 0.1%, of the viscosity of the
polydisperse oil blend after the methods of the present disclosure
have been used to remove the low molecular weight fraction
(including VOCs having a molecular weight less than about 2000
g/mol, such as less than about 1500 g/mol, or less than about 1000
g/mol, or less than about 800 g/mol).
[0069] In embodiments, a polydisperse oil of this disclosure may be
an unsubstituted organopolysiloxane such as, for example,
polydimethylsiloxane (PDMS), diphenylpolysiloxane, or
phenylmethylsiloxane.
[0070] In embodiments, the polydisperse oil may have a
polydispersity index (M.sub.w/M.sub.n) in any desired ranges, such
as in the range of from about 1.05 to about 4, such as in the range
of from about 1.1 to about 3, or from about 1.1 to about 2.4, or in
the range of from about 1.2 to about 2.
[0071] The functionalized polydisperse oil may have functional
groups pendant from at least some of the polymer molecules therein.
The functional groups may be, for example, carboxy, hydroxyl,
epoxy, amino, isocyanate, thioether, mercapto, carbinol, methacryl,
phenol, and the like.
[0072] The molecular weight of the functionalized polydisperse oil
should be sufficient to achieve a high viscosity functionalized
polydisperse oil (relative to the viscosity of the polydisperse oil
diluent). In this regard, the molecular weight of the
functionalized polydisperse oil to be used in the compositions of
the present disclosure may ultimately depend on how the polymer is
functionalized and the specific identity of the functional groups
that are present on the polymer chains. In embodiments, the average
molecular weight (and optionally the polydisperity index) of the
functionalized polydisperse oil may be selected such that the
functionalized polydisperse oil possesses a viscosity in the range
of from about 200 cSt to about 1200 cSt. For example, the average
molecular weight (and optionally the polydispersity index) of the
functionalized polydisperse oil may be in a range that is
sufficient to achieve a viscosity in the range of from about 200
cSt to about 1200 cSt, such as a number average molecular weight
that is sufficient to achieve a viscosity in the range of from
about 200 cSt to about 1200 cSt, or a viscosity in the range of
from about 400 cSt to about 1000 cSt, or a viscosity in the range
of from about 500 cSt to about 800 cSt. In embodiments, such a
functionalized polydisperse oil with the above-mentioned
viscosities may have any desired polydispersity index
(M.sub.w/M.sub.n), such as a polydispersity index of from about 1.1
to about 6, such as about 1.2 to about 4.
[0073] In embodiments, the functionalized polydisperse oil may be
prepared by any suitable method, such as by reacting
amino-functionalized polydimethylsiloxanes.
[0074] Polydisperse Oil/Functionalized Polydisperse Oil Blend
(Fuser Oils)
[0075] In embodiments, a polydisperse oil (diluent) and a
functionalized polydisperse oil are combined to produce a fuser oil
blend. Blending may proceed according to any suitable process.
[0076] For example, a polydisperse oil (diluent) comprising less
than about 0.15% by weight VOCs having a molecular weight less than
about 2000 g/mol may be blended with a functionalized polydisperse
oil to produce a blend including less than about 0.15% by weight
VOCs having a molecular weight less than about 2000 g/mol.
Alternatively, in embodiments, a polydisperse oil (diluent)
including more than about 0.15% by weight VOCs having a molecular
weight less than about 2000 g/mol may be blended with a
functionalized polydisperse oil to produce a blend including more
than 0.15% by weight VOCs having a molecular weight less than about
2000 g/mol. Such blended compositions comprising VOCs may then be
subjected to the precision stripping processes of the present
disclosure to selectively strip the most volatile components of the
oil (for example, those components having a molecular weight of
less than about 2000 g/mol), reducing the content of those most
volatile components of the oil without significantly increasing the
oil viscosity. After being subjected to the stripping processes of
the present disclosure, such blends may have the VOC content
reduced such that the blends include no more than about 0.1% by
weight VOCs having a molecular weight less than about 2000 g/mol,
or no more than about 0.001% by weight VOCs having a molecular
weight less than about 2000 g/mol.
[0077] In embodiments, the polydisperse oil (diluent) may have a
viscosity of from about 100 cSt to about 190 cSt, such as from
about 125 cSt to about 180 cSt, or from about 150 to about 175 cSt,
and the functionalized polydisperse oil may have a viscosity in the
range of from about 200 cSt to about 1200 cSt, such as from about
400 cSt to about 800 cSt. The polydisperse oil (diluent) and the
functionalized polydisperse oil are present in the blend in
relative amounts in an effective ratio to achieve a desired
viscosity. For example, in embodiments, the polydisperse oil
(diluent) component may account for about 70-95% of the blend, and
the functionalized polydisperse oil component may account for about
5-30% of the blend. The resulting blend of the polydisperse oil
(diluent) and the functionalized polydisperse oil may have a
viscosity of from about 75 cSt to about 1500 cSt, such as from
about 100 cSt to about 1000 cSt, or from about 150 cSt to about 700
cSt.
[0078] Volatile Organic Compounds (VOCs)
[0079] In embodiments, the methods of the present disclosure may be
used to reduce the VOC content of polydisperse oil compositions by
at least 50% or reduce the VOC content by orders of magnitude (such
as by a factor or 10 or 100) to arrive at polydisperse oil
compositions that include less than about 0.15% by weight VOCs,
such as less than about 0.1% by weight VOCs, or less than about
0.01% by weight VOCs, or less than about 0.001% by weight VOCs.
[0080] Before being stripped according to the methods described
herein, a polydisperse oil may emit VOCs in a concentration of
greater than about 1.5 PPM (methanol equivalent), such as greater
than about 5 PPM, or greater than about 10 PPM, as measured using a
Flame Ionization Detector (FID). In embodiments, when the polymer
compositions of the present disclosure are heated to a
predetermined temperature, VOCs are emitted in a concentration of
less than about 0.5 PPM (methanol equivalent), such as less than
about 0.1 PPM, or less than about 0.08 PPM, or less than about 0.01
PPM, or less than about 0.001 PPM, as measured using FID.
[0081] The threshold for volatility increases as temperature
increases. Accordingly, in embodiments, such as for solid ink jet
oils, the compositions include less than about 0.15% by weight
VOCs, such as less than about 0.1% by weight VOCs, or less than
about 0.01% by weight VOCs, or less than about 0.001% by weight
VOCs, having a molecular weight less than about 700 g/mol, such as
less than about 550 g/mol, or less than about 450 g/mol. In
embodiments, the composition is substantially free of VOCs having a
molecular weight less than about 700 g/mol, such as less than about
550 g/mol, or less than about 450 g/mol. The phrase "substantially
free" refers, for example, to a polydisperse oil composition in
which the concentration of VOCs approaches zero, such as a
concentration of less than about 0.15% by weight, or less than
about 0.1% by weight, or less than about 0.01% by weight, or less
than about 0.001% by weight.
[0082] In embodiments, such as for fuser oils, the compositions
include less than about 0.15% by weight VOCs, such as less than
about 0.1% by weight VOCs, or less than about 0.01% by weight VOCs,
or less than about 0.001% by weight VOCs, having a molecular weight
less than about 2000 g/mol, or less than about 1500 g/mol, or less
than about 1000 g/mol, or less than about 800 g/mol. In
embodiments, the composition is substantially free of VOCs having a
molecular weight less than about 2000 g/mol, or less than about
1500 g/mol, or less than about 1000 g/mol, or less than about 800
g/mol.
[0083] As discussed above, VOCs are dominated by low molecular
weight components. For example, in embodiments in which the
polydisperse oil is a polydimethylsiloxane, VOCs are primarily
siloxanes. Table 1 illustrates properties of selected high
volatility components of PDMS oil.
TABLE-US-00001 TABLE 1 Selected Cyclic and Linear Organiosiloxane
Properties Vapor Pressure Boiling Water Solubility Name Formula MW
mmHg 77.degree. F. Abbreviations Point .degree. F. (mg/L)
25.degree. C. Hexamethylcyclotrisiloxane
C.sub.6H.sub.18O.sub.3Si.sub.3 222 10 D.sub.3 275 1.56
Octamethylcyclotetrasiloxane C.sub.8H.sub.24O.sub.4Si.sub.4 297 1.3
D.sub.4 348 0.056 Decamethylcyclopentasiloxane
C.sub.10H.sub.30O.sub.5Si.sub.5 371 0.4 D.sub.5 412 0.017
Dodecamethylcyclohexasiloxane C.sub.12H.sub.36O.sub.6Si.sub.6 445
0.02 D.sub.6 473 0.005 Hexamethyldisiloxane
C.sub.6H.sub.18Si.sub.2O 162 31 L.sub.2, MM 224 0.93
Octamethyltrisiloxane C.sub.8H.sub.24Si.sub.3O.sub.2 236 3.9
L.sub.3, MDM -- 0.035 Decamethyltetrasiloxane
C.sub.10H.sub.30Si.sub.4O.sub.3 310 0.55 L.sub.4, MD.sub.2M -- --
Dodecamethylpentasiloxane C.sub.12H.sub.36Si.sub.5O.sub.4 384 0.7
L.sub.5, MD.sub.3M -- --
[0084] For example, in embodiments wherein the polydisperse oil is
a polydimethylsiloxane, the volatile organic compounds having a
molecular weight of less than about 550 g/mol include
hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane,
decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane,
hexamethyldisiloxane, octamethyltrisiloxane,
decamethyltetrasiloxane, and dodecamethylpentasiloxane. FIG. 4
provides a graphical representation of siloxane volatility as a
function of molecular weight. In embodiments, the most volatile
components of the oil are those having the lowest molecular
weight.
[0085] In embodiments in which the polydisperse oil is a
polydimethylsiloxane, cyclic siloxanes (i.e.,
hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane,
decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane)
generally make a greater contribution to the overall VOCs than
linear siloxanes (i.e., hexamethyldisiloxane,
octamethyltrisiloxane, decamethyltetrasiloxane, and
dodecamethylpentasiloxane). In other words, cyclic siloxanes may
make a greater contribution to the VOCs than the linear siloxanes
of similar molecular weight.
[0086] Preparing a Polydisperse Oil Having a Low Content of
VOCs
[0087] The methods of the present disclosure include preparing a
polydisperse oil having a low content of VOCs by removing the low
molecular weight (most volatile) components without substantially
increasing the viscosity. Prior to stripping, a significant
fraction of the molecules in the polydisperse oil may have
molecular weights below the threshold for volatility (such as less
than 550 g/mol, however this value will depend of the molecular
makeup of the polydisperse oil, or the operating temperature of the
oil). Unlike conventional techniques, the stripping processes of
the present disclosure do not remove a large fraction of molecules
with molecular weights both above and below the threshold for
volatility. Thus, the mean molecular weight of the final
distribution of molecules in the stripped oil does not
substantially increase and the viscosity of the polydisperse oil
does not significantly change.
[0088] FIG. 5 provides a graphical representation of the effect of
low precision stripping of low molecular weight components on the
oil molecular weight distribution. Before stripping, a significant
fraction of the molecules in the oil have molecular weights below
the threshold for volatility (for this exemplary composition, less
than about 550 g/mol). Stripping by an aggressive, low-precision
stripping process removes a large fraction of molecules with
molecular weights both above and below the threshold for
volatility. Consequently, the mean molecular weight of the final
distribution of molecules in the stripped oil substantially
increases, which increases the viscosity of the oil (see, for
example, FIG. 1). Although the volatile components of the oil are
successfully stripped, the viscosity increases to such a degree
that it is unfit for use in the printing process.
[0089] According to the methods of the present disclosure, the
volatile components of the polydisperse oil having a molecular
weight below the threshold for volatility, such as, for example, a
molecular weight less than about 550 g/mol, may be selectively
removed without significantly increasing the viscosity of the oil.
FIG. 6 is a hypothetical graphical representation of the effect of
the high precision stripping process of the current disclosure on
oil and exemplary hypothetical molecular weight distribution. In
embodiments, the process of the present disclosure may be utilized
to strip only the very low molecular weight fraction of the oil
that contributes to VOC emissions, leaving the molecules with
molecular weights above the threshold for volatility (for the
purposes of this illustration, the molecules having a molecular
weight greater than about 550 g/mol). As a result, there is no
significant shift in the viscosity because the mean molecular
weight of the oil remains nearly unchanged. For example, the
viscosity of the stripped polydisperse oil may be within about 2%
of the viscosity of the initial unstripped polydisperse oil, such
as within about 1% of the viscosity of the initial unstripped
polydisperse oil. Accordingly, the stripped oil would exhibit both
low viscosity and low VOC emissions because the low molecular
weight components have been stripped from the oil, while the higher
molecular weight components have been retained.
[0090] In embodiments, the method according to the present
disclosure includes the steps of flowing polydisperse oil
comprising VOCs over a surface to form a layer of polydisperse oil,
and then heating the layer of polydisperse oil at an effective
temperature to remove VOCs, and forming a stripped polydisperse oil
substantially free of VOCs.
[0091] In embodiments, the VOCs have a vapor pressure in the range
of from about 0.01 mmHg to about 40 mmHg at 25.degree. C., such as
from about 0.02 mmHg to about 35 mmHg, or from about 0.2 mmHg to
about 5.0 mm Hg at 25.degree. C.
[0092] In embodiments, the methods of the present disclosure result
in a product polydisperse oil in which the viscosity of the
stripped polydisperse oil is within about 2% of the viscosity of
the initial (unstripped) oil, and the mass of the stripped
polydisperse oil is within about 1% of the mass of the initial
oil.
[0093] Examples of the polydisperse oil include, for example,
non-functional polydisperse oils such as silicone oils, including
polydimethylsiloxane (PDMS), or functionalized polydisperse oils,
such as amino-substituted oils, mercapto-substituted oils,
hydride-substituted oils, or the like, and blends thereof.
[0094] In embodiments, the methods of the present disclosure may be
employed with a polydisperse oil in which the polydisperse oil has
a number average molecular weight in the range of from about 800
g/mol to about 3500 g/mol, and a polydispersity index
(M.sub.w/M.sub.n) in the range of from about 1.1 to about 4.0, such
as from about 1.1 to about 3.2.
[0095] The methods of the present disclosure may be effectively
employed on any desired polydisperse oil that comprises VOCs, such
as VOCs having a molecular weight less than about 550 g/mol. For
example, when the polydisperse oil comprises PDMS, the VOCs may
include linear siloxanes and cyclic siloxanes having a molecular
weight less than about 550 g/mol. In such embodiments where the
polydisperse oil comprises PDMS, the methods of the present
disclosure may be performed on an unstripped polydisperse oil
comprising linear siloxanes and cyclic siloxanes having a molecular
weight less than about 550 g/mol, and the stripped polydisperse oil
may contain an amount of linear siloxanes and cyclic siloxanes
having a molecular weight less than about 550 g/mol that is at
least 20 times lower than that of the initial (unstripped)
polydisperse oil. The cyclic siloxanes having a molecular weight
less than about 550 g/mol may be, for example,
hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane,
decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and
combinations thereof. The linear siloxanes having a molecular
weight less than about 550 g/mol may be, for example,
hexamethyldisiloxane, octamethyltrisiloxane, decamethyltrisiloxane,
dodecamethylpentasiloxane, and combinations thereof.
[0096] In such embodiments where the polydisperse oil comprises
PDMS, the methods of the present disclosure may be performed on an
unstripped polydisperse oil comprising linear siloxanes and cyclic
siloxanes having a molecular weight less than about 550 g/mol, and
the stripped polydisperse oil may contain an amount of linear
siloxanes and/or cyclic siloxanes having a molecular weight less
than about 550 g/mol that is at least 20 times lower than that of
the polydisperse oil.
[0097] In embodiments wherein the polydisperse oil is PDMS, VOCs
from the initial (unstripped) oil are dominated by siloxanes. In
embodiments, low molecular weight siloxanes (for example,
hexamethyldisiloxane, hexamethylcyclotrisiloxane) are more
volatile, but there are fewer of these low molecular weight
siloxanes in the unstripped polydisperse oil. In embodiments,
cyclic siloxanes (i.e., hexamethylcyclotrisiloxane,
octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane,
dodecamethylcyclohexasiloxane) make greater contributions to the
amount of VOCs than linear siloxanes (i.e., hexamethyldisiloxane,
octamethyltrisiloxane, decamethyltrisiloxane,
dodecamethylpentasiloxane).
[0098] VOCs may be removed by flowing the initial polydisperse oil
over a surface and heating it at a temperature effective to remove
the VOCs. The oil may be flowed over a surface in a thin layer to
achieve a high surface area to volume ratio. A thinner layer yields
a higher surface area to volume ratio, which leads to a faster and
more complete evaporation of the high volatility components of the
oil. In embodiments, the surface area to volume ratio is in the
range of from about 1 cm.sup.-1 to about 20 cm.sup.-1.
[0099] The oil may be flowed over the surface at a controlled rate
(R.sub.OIL) in mL/min. In embodiments, this rate is from about
[0.04*L.sub.0] to about [10*L.sub.0], where L.sub.0 is the width
(in cm) of the surface over which the oil flows.
[0100] FIG. 7 illustrates one exemplary embodiment of a helical
ramp 100 over which oil may be flowed in order to strip the oil of
VOCs. In embodiments, the width of the ramp 130 (L.sub.0) and the
height of the edge 120 may be set to any desired distance to
accommodate the volume of oil to be stripped at the desired rate.
In embodiments, the oil may flow over the ramp under the force of
gravity. The slope of the ramp (or the distance between successive
vertical points on the ramp 140) may be adjusted to any suitable
value. For example, for more viscous oils, the slope (or the
distance between successive layers 140) may be increased to level
sufficient to allow the oil to flow at a given rate such that the
oil spends a predetermined amount of time on the ramp. A longer
ramp length allows for a more complete stripping of VOCs at the end
of the process. To save space, a helical ramp may be used. In
embodiments, the ramp 100 may contain a center rod-like structure
150, around which the flowing surface proceeds in a helical
fashion, and the stripped oil may be collected at the bottom 110 of
the ramp.
[0101] To increase the evaporation rate, the surface over which the
oil is flowed may be heated. The temperature (T.sub.OIL)
contributes to the range of molecular weights that are removed from
the oil, with higher T.sub.OIL temperatures removing higher
molecular weight components. In embodiments, the polydisperse oil
is a fuser oil or a solid ink oil. In general, the stripping
temperature T.sub.OIL will be greater than the print process
temperature (T.sub.PROCESS). For example, in embodiments, the
polydisperse oil may be a solid ink oil, and T.sub.OIL may range
from about 40.degree. C. to about 120.degree. C., such as from
about 50.degree. C. to about 80.degree. C. Alternatively, the
polydisperse oil may be a fuser oil, and T.sub.OIL may range from
about 140.degree. C. to about 250.degree. C., such as from about
150.degree. C. to about 250.degree. C. More generally, T.sub.OIL
may be from 0.degree. C. to about 40.degree. C. higher than
T.sub.PROCESS, such as from about 5.degree. C. to about 35.degree.
C. higher, or from about 10.degree. C. to about 30.degree. C.
higher, to ensure that the stripping is highly selective and
minimizes viscosity shifts. In embodiments, the ramp may be heated
to a uniform temperature. In embodiments, portions of the ramp may
be set to different temperature profiles to form a temperature
gradient.
[0102] In embodiments, to increase the evaporation rate, gas may be
flowed over the surface at a controlled flow rate. A faster flow
rate yields a higher evaporation rate. Alternatively, to increase
the evaporation rate, the oil surface may also be exposed to a
vacuum. The pressure of the partial vacuum (P) may be
controlled.
[0103] According to the method of the present disclosure, an oil
composition yielding low VOC emissions may be produced without
chemically altering or degrading the oil. For example, the color of
the stripped polydisperse oil may be substantially similar to that
of the initial oil. In embodiments, for example, the color of the
stripped polydisperse oil may be identical to the color of the
initial (unstripped) oil.
[0104] Print System
[0105] In embodiments, the oil composition described herein may be
applied to the surface of a fusing/transfer member in a printer
system for use in printing applications.
[0106] The terms "printer" or "imaging device" refer, for example,
to a device for applying an image to print media. Such device may
encompass any apparatus, such as a digital copier, bookmaking
machine, facsimile machine, multi-function machine, and so forth,
which performs a print outputting function for any purpose.
[0107] Referring to FIG. 8, in a typical solid ink jet printer
system for use in printing applications, a thin film of oil is
applied to the surface 20 of a transfer member, such as a rotating
metallic drum 22. The transfer member described herein can be of
any suitable configuration. Examples of suitable configurations
include a sheet, a film, a web, a foil, a strip, a coil, a
cylinder, a drum, and endless Mobius strip, a circular disc, a belt
(including an endless belt, an endless seamed flexible belt, an
endless seamless flexible belt, and an endless belt having a puzzle
cut seam) and the like. In embodiments, the transfer member is a
metallic drum, such as an aluminum drum.
[0108] Further in reference to FIG. 8, the oil may be applied to
the surface 20 of the rotating metallic drum 22 with a Drum
Maintenance Unit (DMU) 40. In solid ink imaging systems, the DMU is
configured to (1) lubricate the image receiving surface of the drum
with a very thin, uniform layer of the release agent before each
print cycle, and (2) remove and store any excess oil, ink, and
debris from the surface of the drum after each print cycle. DMUs
may include a reservoir for holding a release agent, an applicator
that receives oil from the reservoir and applies oil to the surface
of the drum, and a metering blade for metering the oil applied to
the surface of the drum by the applicator. The printer system may
also contain an image on drum (IOD) or image on web array (IOWA)
sensor 42 to allow a device to measure the various defects or
variations (for example, clogged ink jets and/or misalignment of
ink jets and/or print heads). An IOD or IOWA sensor 42 may be an
image sensor configured to monitor, for example, the presence,
intensity, and/or location of marking material jetted onto a
substrate by the ink jets of the print heads 26. An IOD or IOWA
sensor could generally include, for example, a light source and/or
more optical detectors situated to detect marking material on a
substrate.
[0109] Print heads 26 jet ink onto the oiled surface 20 of the drum
22. It may be necessary for the drum 22 to rotate multiple times to
build the image on the drum surface 20. In a solid ink printer
system, the ink, which is solid at room temperature, is heated (for
example, to about 115.degree. C.) and converted to a liquid in the
print heads 26. The temperature of the oiled drum surface 20 is
lower than that of the liquid ink (for example, about 55.degree.
C.), and the ink cools into a malleable solid shortly after
contacting the drum surface 20. Once the image is built on the drum
surface 20, a media is transported along the media path 50 through
a pre-heater 28 and enters the transfix nip 30, where the ink is
transferred to the media. The transfix roller 32, which in
embodiments comprises a conformable elastomer on a metal shaft, is
brought into contact with the backside of the media, forming the
high pressure nip 30, which ensures the paper makes secure contact
with the ink on the oiled drum surface 20. The oil acts as a
release layer and reduces the adhesive force of the ink to the drum
surface 20, which aids in the transfer efficiency of the ink from
the oiled drum surface 20 to the media. In order to achieve high
transfer efficiency and excellent print quality, the adhesive force
between the media and the ink should be greater than the adhesive
force between the ink and the oiled drum surface 20. Without the
oil, the drum-ink adhesion is too high, resulting in poor transfer
efficiency and poor print quality.
[0110] The terms "media" and "print media" may refer to any
suitable physical print media substrate for images. For example,
potentially suitable media may include paper, substrate,
transparency material such as polyester, polycarbonate, and the
like, cloth, wood, and any other desired material upon which the
finished image will be situated. An image generally may include
information in electronic form which is to be rendered on the print
media by the image forming device and may include text, graphics,
pictures, and so forth.
[0111] Further in reference to FIG. 8, the abatement system 34,
optionally containing a VOC filter 38, pulls air, dust, particles,
and volatile chemicals out of the printer cavity and into the
environment with a fan 36. In embodiments, the exhausted materials
may pass through the fan 36 after passing through the optional VOC
filter 38, as illustrated in FIG. 8. In other embodiments, the
exhausted materials may pass through the fan 36 before passing
through the optional VOC filter 38. In other words, the optional
VOC filter may be externally or internally incorporated into the
abatement system 34.
[0112] In a system featuring the stripped oil, the VOCs emitted by
the oil and exhausted into the environment through the abatement
system 34 are reduced as compared to a system incorporating an
initial (unstripped) oil. In embodiments, the VOC filter 38 may be
optionally removed or eliminated from the system featuring the
stripped oil, as the VOCs emitted by the stripped oil and exhausted
into the environment may be reduced as compared to a system
incorporating an unstripped oil, such as reduced to a level that
satisfies government regulations and/or environmental
certifications, without using the filter.
[0113] Examples are set forth below and are illustrative of
different compositions and conditions that can be utilized in
practicing the disclosure. All proportions are by weight unless
otherwise indicated. It will be apparent, however, that the
disclosure can be practiced with many types of compositions and can
have many different uses in accordance with the disclosure above
and as pointed out hereinafter.
EXAMPLES
Example 1
Preparation of 30 cSt Silicone Oil
[0114] An oil composition was prepared by blending a polydisperse
PDMS diluent having a viscosity of 20 cSt with amino-functionalized
PDMS (amine concentrate) having a viscosity of 400-800 cSt. The
diluent and amine concentrate were combined in a 95:5 ratio of
diluent to amine concentrate. The resulting blend had a viscosity
of 29.8 cSt.
Example 2
[0115] Sample demonstration of a selective, high precision process
for eliminating volatile organic compounds from oil.
[0116] A shallow pool of the 30 cSt silicone oil as prepared in
Example 1 above was placed in a large Erlenmeyer flask sitting on a
hot plate. The ratio of the surface area to the volume was
sufficiently large to ensure a rapid rate of evaporation. The oil
was heated to a temperature of T.sub.STRIP=80.degree. C. under an
airflow of 18 ft.sup.3/min for 80 minutes while monitoring VOC
emissions.
[0117] FIG. 9 presents a graphical representation of VOC emissions
during the low temperature stripping process. VOC emissions
increased initially as the oil was heated, and then dropped
exponentially as the volatile components rapidly evaporated.
[0118] The VOC emissions between the initial and stripped oils were
compared by dripping each oil at a rate of 23 mL/min onto a heated
metal plate (T.sub.PLATE=60.degree. C.) in a chamber with a
controlled airflow (9.7 ft.sup.3/min). The VOC emissions were
measured in PPM (methanol equivalent) using a Flame Ionization
Detector (FID).
[0119] The VOC emissions of the stripped oil were 0.07 PPM
(methanol equivalent) as measured by FID, as compared to 5.5 PPM
(methanol equivalent) for the untreated initial oil. As such, the
VOC emissions of the stripped oil were over 80 times lower than the
emissions from the untreated initial oil. Less than 0.15% of the
total mass of the oil was stripped, indicating that the stripping
was highly selective and removed only the most volatile (i.e.,
lowest molecular weight) components of the oil. A visual inspection
of the oil showed that there was no discoloration of the oil. NMR
analysis indicated that there was no chemical degradation of the
oil.
[0120] The viscosity of the stripped oil was compared to the
viscosity of the initial oil. The average viscosity of the stripped
oil was 29.7 cSt, which is nearly identical to the average
viscosity of 29.8 cSt measured for the initial oil.
[0121] It will be appreciated that various of the above-disclosed
and other features and functions, or alternatives thereof, may be
desirably combined into many other different systems or
applications. Also, various presently unforeseen or unanticipated
alternatives, modifications, variations or improvements therein may
be subsequently made by those skilled in the art, and are also
intended to be encompassed by the following claims.
* * * * *