U.S. patent number 3,640,766 [Application Number 05/001,279] was granted by the patent office on 1972-02-08 for electrophotographic-recording member and process of producing the same.
This patent grant is currently assigned to Nalco Chemical Company. Invention is credited to Stanley F. Ciesla, Myron J. Jursich.
United States Patent |
3,640,766 |
Jursich , et al. |
February 8, 1972 |
ELECTROPHOTOGRAPHIC-RECORDING MEMBER AND PROCESS OF PRODUCING THE
SAME
Abstract
Polyepihalohydrin is quaternized with a trialkyl amine to
produce an electroconductive polymer. The quaternized
polyepihalohydrin is applied to paper to produce a recording
element having an electroconductive surface adapted for
electrographic printing.
Inventors: |
Jursich; Myron J. (Chicago,
IL), Ciesla; Stanley F. (Brookfield, IL) |
Assignee: |
Nalco Chemical Company
(Chicago, IL)
|
Family
ID: |
21695231 |
Appl.
No.: |
05/001,279 |
Filed: |
January 7, 1970 |
Current U.S.
Class: |
430/127; 427/121;
428/704; 162/138; 428/537.5; 430/62; 524/612 |
Current CPC
Class: |
C08G
65/33306 (20130101); G03G 5/107 (20130101); C08G
65/24 (20130101); Y10T 428/31993 (20150401) |
Current International
Class: |
C08G
65/00 (20060101); C08G 65/333 (20060101); C08G
65/24 (20060101); G03G 5/10 (20060101); G03g
005/02 (); D21h 001/28 (); B32h 027/10 () |
Field of
Search: |
;117/201,218,76P,155R,161R,161ZB,34 ;162/138 ;96/1.5 ;260/2A |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Martin; William D.
Assistant Examiner: Speer; Raymond M.
Claims
We claim:
1. A paper having a printing surface adapted for electrographic
printing and containing on said surface a continuous coating in an
amount corresponding to from 0.5 to 2.5 pounds per 3,000 square
feet of the paper, of an electroconductive water-dispersible
polymer having the formula: ##SPC5##
where claim: is a halogen selected from the group consisting of
chlorine, bromine, and iodine, R is independently selected from the
group consisting of methyl, ethyl and (C.sub.n H.sub.2n 0).sub.Y H
where y is an integer from 1 to 30, n is an integer from 1 to 4,
and m is an integer from 5 to 2,000
2. The paper of claim 1 in which X is chlorine, R is methyl and m
is an integer from 20 to 100.
3. The paper of claim 1 in which the water-dispersible polymer
comprises of from 80 to 100 percent quaternary adducts.
4. The paper of claim 3 in which the water-dispersible polymer
comprises of from 80 to 100 percent quaternary adducts where X is
chlorine, R is methyl and m is an integer of from 20 to 100.
5. A method of producing an electrophotographic-recording member
which comprises the steps of:
A. coating a substrate with a dispersion containing from 5 to 50
percent by weight of a water-dispersible polymer having the
formula: ##SPC6##
where X is a halogen selected from the group consisting of
chlorine, bromine, and iodine, R is independently selected from the
group consisting of methyl, ethyl and (C.sub.n H.sub.2n O).sub.y H,
where y is an integer from 1 to 30, n is an integer from 1 to 4,
and m is an integer from 5 to 2,000, so as to form a continuous
coating in an amount corresponding to from 0.5 to 2.5 pounds per
3,000 square feet of the paper;
B. drying the coating of the water-dispersible polymer;
C. applying a layer of an extender selected from the group
consisting of starch, polyvinyl alcohol, polybutyl acetate and
polybutyl styrene; and
D. recoating with an electrophotographic photoconductor selected
from the group consisting of the oxides, iodides, selenides,
sulfides, and tellurides of zinc, antimony, aluminum, bismuth,
cadmium, mercury, molybdenum and lead; selenium; arsenic
trisulfide; lead chromate; and cadmium arsenide to form a final
electrophotographic recording member.
6. The method of claim 5 in which the substrate is paper.
7. The method of claim 5 in which the extender is polyvinyl
alcohol.
8. The method of claim 5 in which the photoconductor is zinc
oxide.
9. The method of claim 5 in which X is chlorine, R is methyl and m
is an integer of from 20 to 100.
10. The method of claim 5 in which the water-dispersible polymer is
formed by the substantially complete quaternization of a trialkyl
amine and polyepihalohydrin.
11. The method of claim 10 in which the water-dispersible polymer
comprises of from 80 to 100 percent quaternary adducts.
12. The method of claim 11 in which the water-dispersible polymer
comprises of from 80 to 100 percent quaternary adducts where X is
chlorine, R is methyl and m is an integer of from 20 to 100.
Description
In the manufacture of paper having a printing surface adapted for
electrographic printing, it previously has been found difficult to
provide the paper with a coating of an electroconductive substance
that is dispersible in water and has the necessary
electroconductive properties. One group of compounds which has been
found to be useful comprises a polymer consisting of a polymerized
vinyl-benzyl quaternary ammonium compound, disclosed in U.S. Pat.
No. 3,011,918 to Silvernail et al. However, paper coated with these
compounds suffers from an objectionably strong aminelike odor which
can only be reduced by lowering the pH of the coating to a very
acid range in which corrosion of the coating apparatus is promoted.
Further, these compounds are expensive and a more economical, as
well as satisfactory, electroconductive polymer has been
sought.
It would be a great advantage to the art if a water-dispersible
polymer was found that had electroconductive properties and no
significant disadvantages. It would also be an advantage to the art
if a relatively simple method of imparting electroconductivity to a
substrate could be devised.
OBJECTS
It is an object of this invention to produce an electroconductive
polymer.
It is a further object of this invention to produce a polymer that
is water soluble or water dispersible that can be used to produce a
recording element having the electroconductive surface adapted for
electrographic printing. Another object is to produce a paper
having a surface adapted for electrographic printing.
Still another object of this invention is to devise a method of
producing an electrographic recording member.
Further objects will be evident to those skilled in the art.
THE INVENTION
The invention relates to the manufacture of substrates having
electroconductive properties useful when the substrate is employed
as a recording element in an electrographic printing process. More
particularly, this invention relates to paper having the
electroconductive surface adapted for electrographic printing and
containing a polymer comprised of quaternized polyepihalohydrin and
preferably quaternized polyepichlorohydrin.
It has been discovered in accordance with the present invention
that polymers of quaternized polyepihalohydrin can be prepared
economically and can readily be applied as a coating to paper to
produce a product having an electroconductive surface and
possessing electroconductive properties over a wide relative
humidity range. Paper coated with quaternized polyepihalohydrin, in
accordance with the present invention, has a surface resistivity
ranging from about 5.times.10.sup.8 to 1.times.10.sup.5 ohms per
square centimeter over a relative humidity range of from about 8 to
75 percent.
THE POLYMERS
The electroconductive water-dispersible polymer has the formula:
##SPC1##
where X is a halogen selected from the group consisting of
chlorine, bromine, and iodine, R is independently selected from the
group consisting of methyl, ethyl and (C.sub.n H.sub.2n O).sub.y H,
where y is an integer from 1 to 30, n is an integer from 1 to 4,
and m is an integer from 5 to 2,000. Preferably, X is chlorine, R
is methyl, and m is an integer from 20 to 100. This polymer can be
easily prepared from the substantially complete quaternization of a
trialkyl amine or a trioxyalkyl amine and polyepihalohydrin.
Preferably, the polyepihalohydrin is polyepichlorohydrin and this
is quaternized with trimethyl amine. Preferably the polymer is
substantially completely quaternized, meaning the the polymer
contains from 80 to 100 percent quaternary adducts having the
formula: ##SPC2##
where X is a halogen selected from the group consisting of
chlorine, bromine, and iodine, R is independently selected from the
group consisting of methyl, ethyl, and (C.sub.n H.sub.2n O).sub.y
H, where y is an integer from 1 to 30, n is an integer from 1 to 4,
and m is an integer from 5 to 2,000. Partially quaternized
polyhalohydrins have been tested and found that when the amount of
quaternization is below 70 percent the paper lacks the necessary
electroconductive activity. Therefore, as stated, the polymers
should be from 80 to 100 percent quaternized and more preferably
from 90 to 100 percent quaternized.
To produce the quaternary polyepichlorohydrin of the desired
molecular weight, namely those having a molecular weight of from
about 750 to 300,000, and preferably from 2,000 to 150,000, it is
necessary to choose an appropriate molecular weight of the
polyepihalohydrin. Polyepihalohydrins having molecular weights
ranging from 450 to 180,000 have been tested and found to produce
continuous films of coatings containing these polymers to paper
without any operational difficulties. Preferably, the epihalohydrin
has a molecular weight ranging from about 1,200 to 100,000.
The amine is preferably trimethyl or triethyl amine. But other
amines could be used, such as methyl diethyl amine, ethoxy dimethyl
amine, as well as mixtures of amines. The alkyl groups are
independently selected from methyl, ethyl, and (C.sub.n H.sub.2n
O).sub.y H, where y is an integer from 1 to 30, n is an integer
from 1 to 4, and m is an integer from 5 to 2,000.
THE METHOD
The method of preparing the electrographic recording member of this
invention comprises the following steps.
1. Coating a substrate, preferably paper, with a dispersion
containing from 5 to 50 percent of a water-dispersible polymer
having the formula ##SPC3##
where X is a halogen selected from the group consisting of
chlorine, bromine, and iodine, R is independently selected from the
group consisting of methyl, ethyl, and (C.sub.n H.sub.2n O).sub.y
H, where y is an integer from 1 to 30, n is an integer from 1 to 4,
and m is an integer from 5 to 2,000, so as to form a continuous
coating in an amount corresponding to from 0.5 to 2.5 pounds per
3,000 square feet of the paper. The term dispersion includes
solution, if the polymer is completely or partially water
soluble.
2. Drying the coating of the water-dispersible polymer.
3. Applying a layer of an extender selected from the group
consisting of starch, polyvinyl alcohol, polybutyl acetate, and
polybutyl styrene.
4. Recoating with an electrographic photoconductive compound
selected from the group consisting of the oxides, iodides,
selenides, sulfides, and tellurides of zinc, antimony, aluminum,
bismuth, cadmium, mercury, molybdenum and lead; selenium; arsenic
trisulfide; lead chromate; and cadmium arsenide to form a final
electrophotographic recording member.
To accomplish the above steps of preparing a substrate having an
electroconductive surface coating, the electroconductive polymers
of this invention can be applied as a continuous film to paper by
coating, spraying dipping, brushing or by any other suitable
application. The quaternized polymer is preferably applied to
paper, as a coating, in the form of an aqueous dispersion or
solution. The coated paper is then dried to produce a product
having an electroconductive surface. Suitable or standard coating
devices such as a blade coater, have been used and the coated paper
has been dried by the use of radiant energy from heat lamps. The
coating can be applied to paper at a range of from 0.5 to 2.5
pounds pickup per 3,000 square feet of paper. Other components can
be formulated with this polymer such as clay, starch, pigments,
etc.
For the substrate, paper is preferred, including high wet-strength
paper coated or uncoated, having a thickness of from 3 to 6 mils.
Other electrically conductive or semiconductive materials may be
used, such, for example, as plastic films including cellophane,
cloth, and metallic foils, e.g., aluminum and copper foils.
Preferably, the water-dispersible quaternized polyepihalohydrin is
polyepichlorohydrin quaternized with trimethyl amine. The extender
is preferably polyvinyl alcohol but could be any extender well
known in the art. In certain conditions the extender could be
eliminated. Preferably, the electrophotographic photoconductor is
zinc oxide, which is a well-known extender.
Other particularly suitable photoconductors for use in the present
process are inorganic products such as, for example, the oxides of
antimony, aluminum, bismuth, cadmium, mercury, molybdenum and lead.
As mentioned, preferred use is made of zinc oxide. When high-grade
layers are to be manufactured, the zinc oxide to be used should be
as pure as possible and advantageously is a product prepared by the
so called French method, that is to say by atmospheric oxidation of
zinc vapor. In any case the photoconductor should be finely divided
and preferably have a particle size below 1 micron.
Other polymers may be mixed with the quaternized polyepihalohydrin
before application of the coating to a paper substrate. A polymer,
such as starch, may be used as a component of the coating
formulation to prevent strike through of the electroconductive
polymer by keeping the latter on the surface of the paper. While
the use of a polymer such as starch adds very little to the
electroconductive properties of the coated paper, it may be used
for the above-indicated purpose. The starch-quaternized
polyepihalohydrin coating may contain any proportion of starch up
to about a ratio of about 1:1, starch to electroconductive
polymer.
The electroconductive water-dispersible polymers are easily
prepared. The following examples illustrate the preparation of the
polymers.
EXAMPLE I
Thirty-eight hundred parts of epichlorohydrin is charged to a
glass-lined reactor, agitated and sampled for water analysis. If
the water content is too high (above 0.2 percent) a portion of the
epichlorohydrin is distilled off, and the charge is maintained by
the addition of fresh epichlorohydrin. After the water content is
low enough, (below 0.2 percent) the vessel is shut in and cooled at
60.degree. C. under a nitrogen pressure of 3-5 p.s.i. A nitrogen
blanket is maintained during the catalyst addition with the kettle
open to the atmosphere through the condenser.
Approximately 160 pounds of 25 percent triisobutyl aluminum in
toluene is added slowly under close supervision at
60.degree.-70.degree. C. until an exothermic reaction is noted. The
temperature is allowed to rise controllably to 100.degree. C. with
cooling as required. When the initial reaction subsides, the
temperature is maintained at 100.degree.-110.degree. C. by catalyst
additions until no more exothermic reaction is noted. The
temperature is lowered to 80.degree.-85.degree. C.
Twenty-five gallons (208 pounds) of water are added below
85.degree. C. The batch is stripped at 22 inches vacuum (minimum)
to a temperature of 100.degree.-110.degree. C. to remove 1-2 drums
of condensate.
Calculate the total weight of reactor contents from materials added
and removed. The charge in weight percent for the following step is
as follows:
26.2 percent Reactor contents
73.8 percent 25 percent aqueous trimethylamine.
Add the trimethylamine below 80.degree. C. The kettle is vented
briefly to bring it to atmospheric pressure.
The kettle is then closed from the atmosphere and heated to 100
p.s.i.g. which should be approximately 90.degree.-100.degree. C.
Hold for 16 hours. Increase the temperature slowly keeping at 100
p.s.i.g. and hold at 130.degree.-140.degree. C. for 2 hours.
Cool to 70.degree.-80.degree. C. and neutralize to pH 5.5 to 6.5
with 250-500 pounds of 30 percent aqueous hydrochloric acid.
EXAMPLE II
Seven hundred fifty parts by weight epichlorohydrin (containing
0.64 part water) was placed in a reactor equipped with agitation
and cooling under a nitrogen blanket. A solution of 25 percent
triisobutyl aluminum in toluene was added in increments at
60.degree. C. until evidence of exothermic reaction appeared.
Twenty-eight parts was required to initiate the reaction.
The heat of reaction increased the temperature of the reaction
mixture to 115.degree. C. in 20 minutes. Temperature was maintained
at 100.degree. C. to 115.degree. C. for 11/2 hours with cooling.
During this time an increase in the apparent viscosity of the
reaction mixture occurred. After the reaction subsided to the
extent that cooling was no longer required, incremental catalyst
addition was resumed at 75.degree. to 100.degree. C. and 12 parts
was added during a 3 -hour period with the temperature maintained
by the heat of the reaction. The temperature was maintained at
90.degree. to 100.degree. C. for additional 11/2 hours.
At the end of this period, 25 parts water was added to destroy
residual catalyst, and the temperature was increased to 150.degree.
C. over a 11/2 hour period to remove 106 parts condensate.
The residue was a pale amber viscous liquid which was soluble in
toluene and xylene and insoluble in isopropyl alcohol.
EXAMPLE III
One hundred thirty-eight parts by weight of the product of Example
II was placed in a pressure vessel equipped with agitation and
heating along with 130 parts of a 3 -mole ethylene oxide adduct of
dimethylamine and 182 parts of 25 percent solution of
trimethylamine in water and heated at 100.degree. C. for 17 hours,
during which time the pressure fell from 47 p.s.i.g. to a slight
vacuum in the reactor. The reaction mixture was neutralized to a pH
of 5.1 with 23 parts of 30 percent hydrochloric acid.
A clear brown viscous liquid was obtained which was very soluble in
water.
EXAMPLE IV
Ninety-three parts by weight of the product of Example II was
heater to 140.degree. C. with agitation and 177 parts of a 3 -mole
ethylene oxide adduct of dimethylamine added in portions over a 1
-hour period. The reaction mass was cooled to 110.degree. C. and 50
parts water added. Heating was applied and the reaction mass held
at reflux (112-116.degree. C.) for 5 hours, at which time 50 parts
water was added and the mixture neutralized to a pH of
approximately 6 with 35 parts 30 percent hydrochloric acid.
EXAMPLE V
One hundred seventy-six parts by weight of the product of Example
II was heated at 150.degree. C. with agitation and 251 parts of a 5
-mole ethylene oxide adduct of dimethylamine was added over a 1
hour period. The temperature was held at 128.degree. C. for 4
hours, after which 100 parts water was added and the reaction
mixture neutralized to a pH of about 6 with 29 parts 30 percent
hydrochloric acid.
EXAMPLE VI
One hundred twenty-one parts by weight of the product of Example I
was heated with 520 parts of 25 percent trimethylamine in water in
a pressure vessel with agitation for 16 hours at 100.degree. C.
Five hundred forty-nine parts of this product was neutralized to a
pH of about 6 with 24 parts 30 percent hydrochloric acid.
EXAMPLE VII
Forty-two parts by weight of the product of Example II was heated
with 81 parts of 7 -mole ethylene oxide adduct of dimethylamine and
59 parts 25 percent aqueous trimethylamine in a pressure vessel
with agitation for 16 hours at 100.degree. C. Five hundred fifteen
parts of this product was neutralized to a pH of about 6 with 51
parts 30 percent hydrochloric acid.
EXAMPLE VIII
Seventy parts by weight of the product of Example II was heated
with agitation to 145.degree. C. and 199 parts of a 7-mole ethylene
oxide adduct of dimethylamine was added over a 30 -minute period.
The reaction mass was held at 130.degree. to 140.degree. C. for 4
hours and 50 parts water added. Heating was continued at reflux
(112.degree. C.) for an additional 2 hours. Fifty parts water was
added and the reaction mass neutralized to a pH of approximately 6
with 32 parts 30 percent hydrochloric acid.
EXAMPLES IX
Thirty-five parts by weight of the product of Example II was heated
with 99 parts of an 11 -mole ethylene oxide adduct of dimethylamine
and 46 parts 25 percent aqueous trimethylamine in a pressure vessel
with agitation for 16 hours at 100.degree. C. Five hundred
twenty-six parts of this product was neutralized to a pH of about 6
with 39 parts 30 percent hydrochloric acid.
Polyepibromohydrin and other amines may also be used to produce
similar products.
ELECTROCONDUCTIVITY TEST
The coated substrate is tested for surface resistivity by a
standard procedure substantially like that described in "Standard
Methods of Test for Insulation Resistance of Electrical Insulation
Materials," A.S.T.M. designation: D257-46.
In the practice for preparing a printed surface for an
electrographic printing process the steps are followed as
previously described in the method of preparing electrophotographic
surfaces. A 40 percent solids concentration of the quaternized
polymer of Example I in water was used. Five hundred volts
potential was applied to a sheet of paper after conditioning at 20
percent relative humidity and 50 percent relative humidity for 36
hours. The results are listed in the following table. ##SPC4##
The papers used designated as No. 1 and No. 2 were standard papers
used in the industry for electrophotography. For example, the paper
weighs 80 grams per square meter and is made from a moderately
beaten papermaking furnish of bleached chemical wood pulp, ground
wood, and chemical clay filler and fiber, rosin size precipitated
by aluminum sulfate.
This table shows that the paper has a much less surface resistivity
and therefore a much greater conductance when the quaternized
polymer is applied to the paper. Therefore, the polymer-coated
paper met the standards of the industry for use in
electrographic-printing processes.
Other quaternized polyepihalohydrins of the examples may be used
and give good results as electroconductive polymers. Similarly,
other substrates such as cellophane, cloth, and metallic foils
could be used.
SUMMARY
From all of the above samples, it is apparent that
polyepihalohydrins have molecular weights ranging from 450 to
180,000 can be quaternized to produce quaternized
polyepihalohydrins which can be employed as coatings to impart
electrical conductivity properties.
Various changes can be made in the illustrative examples
specifically set forth above without departing from the spirit of
our invention or the scope of the appended claims.
* * * * *