Note: Descriptions are shown in the official language in which they were submitted.
104~i8Z4
This invention related to an electrophotographic
recording material, and more specifically to a new electro-
photographic recording material formed in a unitary structure
by extrusion.
One known method for electrophotographic recor~;ng
involves charging the sur~ace of an electrophtographic re-
` cording material, projecting a light image onto the charged
surface to form a latent image, adhering a toner to the latent
image area to develop it, and fixing it in situ or after
transferring it to a copying paper. Electrophotographic
recording materials for use in such an electrophotographic
recording system are prepared by dissolving a thermoplastic
resin such as a styrene resin or aIkyd resin in an organic
solvent such as toluene or xylene, dispersing in the solution
a photoconductive powder, such as zinc oxide or titanium
oxide, which absorbs photon upon exposure to light, and coat-
ing the resulting dispersion on the surface of pulp paper.
However, these conventianal electrophotographic recording
materials are susceptible to humidity which affects their
;.~
electrophotographic recording properties. When the humidity
is above 90% or below 40%, it is difficult to obtain good
recorded images on such recording materials. The practice
~i
has also been developed to form a size layer on the surface
of paper in order to prevent the permeation of the organic
solvent into the paper when coating the above dispersion
containing the photoconductive substance. However, the
formation of a size layer results in the deterioration of
the characteristics of the recorded images or in the coiling
up of the paper during development or fixationO In
:
~0468Z4
an attempt to overcome this disadvantage, a size layer is also formed on
the back of the paper, or a thicker sheet of paper is used to impart strength
to the coated layer. But this leads to the defect of heavier weight.
The electrophotographic recording materials obtained by the method
described above are suitable for recording on one surface of pulp paper, but
in order to record images on both surfaces of the paper, it is necessary to
form a photosensitive layer on both surfaces. Even when electrophotographic
recording is performed using a material hsving a photosensitive layer on
both surfaces, it is difficult to obtain electrophotographic recording images
of good qu~lity on both surfaces.
Accordingly, a primary object of this invention is to provide an
electrophotographic recording material prepared by an extrusion method, which
eliminates the above defects of the conventional electrophotographic record-
ing materials, and which is not affected by humidity, gives a clear recorded
image with rapid light decay by corono charging, and can also permit the
formation of electrophotographic recorded images on both surfaces thereof.
, According to this invention, there is provided an electrophoto-
graphic recording material comprising a melt shaped blend of: (A) an electric-
ally insulating thermoplastic resin; (B) 0.0001 to 40 parts by weight per 100
parts by weight of the thermoplastic resin (A) of a light-sensitizing organic
compound which is a dye, electron-acceptor or electron-donor; (C) 100 to 900
parts by weight per 100 parts by weight of the thermoplastic resin (A) of a
particulate photoconductive inorganic substance, the particles of (C) having
the light-sensitizing organic compound (B) adsorbed thereon; and (D) 0.02 to
1 part by weight per 100 parts by weight of the photoconductive substance
(C) of a metal salt of a saturated or unsaturated fatty acid, the metal being
of Group IIa, IIb (except radium) or IVb of the Periodic Table.
-- 3 --
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... .
10468Z4
~- c~truoion.
The electrophotographic recording material of this
invention which is ~ormed in a unitary structure by extrusion
techniques has not been known prior to the present invention.
This new electrophotographic material will be described in
greater ~etail below.
~ he thermoplastic resin (h) used in this invention
may be any thermoplastic resin which has good electric insula-
tion. Suitable thermoplastic resins include, for example,
olefin resins, styrene resin, vinyl resins, and acrylate
resinsO These resins are used either singly or in admixture
; of two or more. Examples of especially suitable thermoplastio
resins are a homopolymer of ethylene, copolymers of ethylene
.
; with other copolymerizable monomers (e.g., vinyl acetate,
lS vinyl chloride, styrene, propyrene, alkyl acryl~tes, acrylamide,
aluminum acrylate, magnesium acrylate), a homopolymer of
propylene, copolymers of propylene with other copolymerizable
monomers (e.g., vinyl acetate, ethylene, di-cyclo pentadiene,
vinyl alcohol, 1,4-hexadiene~, a homopolymer or styrene, a
styrene/a-methylstyrene copolymer, an acrylonitrile/butadiene/
styrene copolymer, and a homopolymer or vinyl chloride.
~ he powder of the photoconductive inorganic sub-
stance (C) used in this invention is a semi-conductor sub-
stance which when exposed to light, causes an increase in
electric conductivity by absorption of photon from incident
light. In the present invention, those composed of metal
oxides such as zinc oxide or titanium oxide, or those composed
of metal sulfides such as zinc sulfide or cadmium sulfide are
most suitable. Preferably, these photoconductive substances
10468Z4
are used in the po~dery or granular form, and those having
an average particle diameter of 0.1 to 10 microns are suitable.
Where the photoconductive substance has a particle diameter
within this range, the resulting recording material can be - -
uniformly chargedO
In addition to the above-described ingredients,
at least one light-sensitizing organic compound (B) selecte~
; from the group consisting of org~nic ~ye compounds, electron-
accepting organic compounds, and electron-donating organic
compounds is used~
The organic dye compounds may be a ny substance
,~ . .
which has the property of increasing the conductivity of the
above photoconductive inorganic substance (C) on the interface
between it and the photoconductive inorganic substance (C)
i 15 upon absorption of visible light rays. Suitable organic dye
compounds include, for example, acid dyes such as Rose Bengal,
Phloxin, Erythrosin B, Eosine, Ur~mine or basic dyes such as
Rhodamine B, Methylene Blue, Acri~ine Orange, Fuchsin, or
Crystal VioletO They are used either singly or in combination
of two or more. There can also be used reactive dyes such as
SUNISIX Brilliant Blue EB (product o~ Sumitomo Chemical Co.,
~td), CIBACRON Brilliant Red 2G-P (CO Io Reactive Red 15),
PROCION Brilliant Red ~I-8P (C~ Io Reactive Red 31) and Lh~ASIX
Brilliant Red E-4B (C. I. Reactive Red 41), or direct dyes such
~ 25 as Direct ~ist Orange S (CO Io Direct Orange 26), SU~IILIGHT
i Red 4B (CO Io Direct Red 81) and Nippon Resin Fist Scalet
4BA (CO Io Direct Red 230).
The electron-accepting organic compounds that can be
used may be any compound which has the property of increasing
., .
~ _ 5 _
10468Z4
the conductivity of the photoconductive inorganic substance
(C~ by acceptin$ electrons on the interface between it and the
photoconductive inorganic substance. Suitable electron-accep-
ting organic compounds are compounds containing aromatic
rings, such as maleic acid, maleic anhydride, fumaric acid,
phthalic acid, ph~halic anhydri~e, isophthalic acid, tereph-
thalic acid, hemimellitic acid, hemimellitic anhy~ride, tri-
mellitic acid, trimellitic anhydride, glycolic acid, methoxy-
acetic acid, aromatic monob~sic acids (eOg., benzoic acid,
iodobenzoic acid, salicyric ac~id)~uinonic acid, or tetracyano-
; p-benzoquino-dimethane, or 2,4,7-trinitrofluorenoneO Of these,
maleic acid, maleic anhydride, phthalic acid, phthalic anhydride
and benzoic acid are preferredO These compounds are used either
- singly or in combination of two or more~
s 15 The electron-donating organic compoun~'s that can be
used may be any compound which has the property of increasing
the conductivity of the photoconductive inorganic substance
(C) by donating electrons on the interface between it and the
photoconductive inorganic substance (C)~ Suitable electron-
donating organic compounds include, for example, pyrene,
anthracene, coronene, 1,2,~,6-aibenzoanthracene, 1,2-benzo-
anthracene, anthanthrene, ovalene, pyranthrene, tetracene,
violanthrene, iso-violanthrene, pentacene, dimethylaniline,
p-phenylenediamine, tetramethyl-p-phenylenediamine, durene-
diamine, 1,5-diaminophthalein, 1,6-diaminopyr~ne, phenothiazine,
tetrathiotetracene, and tetramethylbenzidine. Of these,
pyrene, anthracene and phenothiazine are especially preferred.
These compounds are used either singly or in combination of
two or more.
- 6 -
1046824
It is suitable, though not essential, for the organic
compound (B) to be adsorbed onto the surface of the photocon- -
ductive inorganic powder (C) when dispersed in the thermo-
plastic resin (A). Suitable methods for causing the organic
com~ound (B) to be adsorbed to the photoconductive inorganic
substance (C) include a wet method which comprises adding the
photoconductive inorganic powder (C~ to a solution or dis-
persion of the organic compound (B), separating the powder of
photoconductive inorganic substance (C) from the m;~ed solu-
tion or dispersion, and then drying it~ and a semi-dry method
which comprises mixing the powder of photoconductive inorganic
substance '~C) with a solution or dispersion of the organic
compound (B) in a small amount of a liquid in a ball mill,
pulverizer, supermixer, or ribbon blender.
In the case of the wet method, the amount of the
organic compound (B) to be dissolved or dispersed is preferably
to 1 mol/liter-solvent, and finally, the amount dissolved
or dispersed in the solution or dispersion is 10 3 to 10
mol/liter-solvent. When the amount of the organic compound (B)
to be dissolved or dis~ersed is 10 to 1 mol/liter-solvent,
the pho~oconductive inorganic substance (C) adsorbed to the
surface of the organic compound (B) has superior photoconduc-
tivity, and the light decay characteristics of the resulting
electrophotographic recording material become superior.
However, when the amount of the organic compound (B) dissolved
or dispersed is smaller than 10 mol/liter, the photoconduc-
tivity of powder of the photoconductive inorganic substance
(C) adsorbed to the surface of the organic compound (B) is
reduced, and the light decay characteristics of the electro-
` ~04ti824
photographic material obtained by the present invention tend to be deter-
iorated. A similar tendency is observed also when the unt of the organic
compound (B) dissolved or dispersed exceeds 1 mol/liter.
The amount of the organic compound (~) absorbed to the surface of
the photoconductive inorganic substance (C) varies over a wide range
according to the type of the organic compound (B) or the type of the
photoconductive inorganic substance tC). Generally, the preferred amount
is at least 10 per gram of the substance (C). More preferably, the amount
~,:
is at least 10 ~ mol per gram of the~photoconductive inorganic substance
(C). When the amount of the organic compound (B) absorbed is within the
above-specified range, the light decay characteristics of the electrophoto-
' graphic recording material obtained by this invention are improved, and
images formed on the recording material have superior clearness and resolving
power.
The suitable amount of the photoconductive inorganic substance
(C) is 100 to 900 parts by weight per 100 parts by weight of the thermo-
plastic resin (B). Most preferably, the amount of the inorganic substance
(C) is 150 to 600 parts by weight on the same basis. The organic compound
(B) is suitably used in an amount of 0.0001 to 40 parts by weight, most
suitably 0.01 to 10 parts by weight, per 100 parts by weight of the thermo-
plastic resin.
The use of the metal salt (D) of a saturated or unsaturated fatty
acid makes it possible to decrease the electric charge on the surface of
the resulting electrophotographic recording material to a suitable level
during electrophotographic recording, to improve the light decay character- -
istics of electrical potential, and to remove the residual electric charge.
Furthermore, the metal salt (D) acts as a lubricant at the time of preparing
the electrophotographic recorddng material, and brings about an increase in
the amount of the material extruded during extrusion molding, which leads
to the formation of an electrophotographic recording material having good
surface characteristics.
Bl - 8 _
10468Z4
Examples of the saturated fatty acid or unsaturated fatty acid
used for forming the metal salt (D) are caprylic acid, capric acid, citro-
nellic acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic
acid, linolic acid, linoleic acid, arachidic acid, clupanodonic acid,
nisinic acid, and zoomaric acid. Suitable saturated or unsaturated fatty --
acids are those containing at least 8 carbon atoms. Those containing 12
to 20 carbon atoms give best results.
Suitable metals of Groups IIa, IIb or IVb of the periodic table
used for preparing the metal salts (D) include, for example, magnesium,
calcium, barium, zinc, cadmium, tin, and lead. The use of radium of Group
II of the periodic table should be avoided since it is a radioactive element
and its radioactivity adversely affects the photographic recording properties
of the material.
The suitable amount of the metal salt (D) is 0.02 to 5 parts,
especially 0.1 to 1 part by weight, per 100 parts by weight of the photo-
conductive inorganic substance.(C).
If desired, an additive such as a ~ubricant, stabilizer, pigment,
or solvent can be incorporated into the electrophotographic material of
this invention. The amount of the additive is within such a range as will
not adversely affect the photoconductive properties of the recording
material.
The melt shaped blend forming the electrophotographic recording
material of the invention preferably also comprises an electrically insul-
ating inorganic powder (E). As the electrically insulating inorganic
powders (E), those having a volume inherent resistivity of at least 103~.cm
are suitableO Most suitably, the volume inherent resistivity is lolon~cm~
Suitable electrically insulating inorganic powders tE) include,
for example, diatomaceous earth, talc, kaolin, clay, calcium carbonate,
magnesium carbonate, barium sulfate, alumina, mica powder, asbestos powder,
calcium sulfate, barium sulfate, lithopone, zinc sulfide, titanium oxide,
_ g _
~, ~}i ,
1046824
and zinc oxide. These powders suitably have a particle diameter within the
range of 0.5 to S microns. The suitable amount of the electrically insul-
i ating inorganic powder is 1 to 100 parts by weight per lO0 parts by weight
of the thermoplastic resin.
When the electrically insulating inorganic powder (E) is used, a
part of it is exposed to the surface of the resulting electrophotographic
recording material to increase the fixation of toners. Furthermore, the
use of the inorganic powder leads to the further growth of the porous
structure generated as a result of the stretching of the fabricated article
- 10 as will be described below. Also, it markedly reduces the tendency of the
electric charge to dissipate during electrophotographic recording, and
prevents the light decay characteristics from decreasing.
The electrophotographic recording material of this invention can
; be shaped into any desired form according to the purpose of use, and the
desired form of use, etc.
Fabrication of the recording material can be performed by various
conventional fabricating methods such as extrusion molding, injection molding,
rolling, compression molding, blow molding, and deep-draw molding, and in
the present specification and the appended claims, all of these fabricating
methods will be referred to simply as "extrusion". The fabricated material
may be in any form such as films, sheets, plates, rods, or tubes. For
example, when it is desired to obtain a sheet-like material, the thermo-
plastic resin (A), the organic compound (B), and the photoconductive inor-
ganic substance (C) are mixed and kneaded, and melted, and the molten mixture
, is subjected to calender rolls to form it into a sheet. Alternatively, the
mixture can be extruded into a sheet form by an extruder. Other methods can
also be used to prepare a sheet-like molded article.
Films can be formed by a variety of methods, such as a method
comprising heating the sheet-like material obtained above and then cold
calendering it, a method comprising stretching the sheet-like material in
- 10 -
~ ~ B
-
~046824
at least one direction, or a method comprising extruding the molten mixture
from a circular die into a tubular article, blowing it by an inflation method,
and then cutting it open into a film shape.
The thickness of the fabricated artic~e is not critical, but
generally, the suitable thickness is 5 to 30 microns. Most suitably, the
thickness is 10 to 20 microns. The fabricated article so obtained is such
that the organic compound (B) and the powder of photoconductive inorganic
substance (C) are uniformly dispersed in the thermoplastic resin tA), and
has a semi-transparent or non-transparent paper-like surface. Such a
10 fabricated article becomes a good electrophotographic recording material.
Thus, the recording material of this invention differs from the
conventional recording materials in that it is fabricated by "ex~rusion".
The electrophotographic recording material of this invention may
be irradiated with ionizing radioactive radiation or ionizing non-radioactive
radiation prior to electrophotographic recording, in order to better the
- surface potential at the time of charging, the surface potential retentionin dark places, and decay characteristics of the surface potential at the
time of exposure, and to obtain recorded images having high density and
being free from fog.
Suitable ionizing radioactive rays are, for example, -r~ys,
~-rays, y-rays, accelerated electron beams emitted from an electron beam
; generator, and X-rays which are electro-magnetic waves emitted from an X-ray
generator. The y-rays, X-rays, and the accelerated electron beams are most
suitable.
Suitable ionizing non-radioactive radiation can be ultraviolet
rays, distant ultraviolet rays, and rays obtained by passing an ionizing
radioactive ray through a shield, for example, a shield made of lead.
,. The irradiation can be effected in accordance with any conventional
methods in vacuum, an atmosphere of an inert gas, or an atmosphere of air.
; 30 Tho irradiation do~e is preferably 102 to 108 rad., and most preferably 103
. .
,:
- 1 1 --
1046824
- to 10 rad., in the case of ionizing radioactive rays. In the case of
ionizing radiant rays, the suitable dose is 104 to 101 erg/g, and the
most suitable dose is 105 to 10 erg/g.
It has been found that the irradiation of the electrophotographic
recording material of the present invention results in a marked improvement
in the characteristics of the recording material which are required for
electrophotographic recording, such as the surface charge generated by
corona discharge at the time of copying operation, the retention of surface
; potentials in dark places, or the decay characteristics of the surface
potential when exposed to light.
According to this invention, the electrophotographic recording
material obtained as shown above can be further stretched to form a micro-
porous structure therein. In the electrophotographic recording material
so obtained, toners are fixed even to the insides of the pores of the
; microporous structure. Furthermore, the tensile strength, tear strength,
impact strength, and other mechanical strength characteristics can be
further increased, and the surface of the recording material permits printing
or writing. Moreover, the resulting electrophotographic recording material
is light in weight and has high degree of non-transparency. In this case,
the stretching of the recording material is preferably carried out at a
temperature below the melting point of the thermoplastic resin (A) which
` constitutes the recording material and a temperature at which molecular
orientation occurs effectively.
The stretching can be performed in one direction only, or in at
least two different directions simultaneously or successively. A tubular
stretcher is the most general stretching machine for stretching the material
in a plurality of different directions, while a tenter stretching machine is
suitable as a biaxial stretcher. The stretch ratio is desirably at least
1.5X in one direction, and by controlling the stretch ratio properly, the
porosit~ of the resulting micropores can be adjusted. The stretching of
,
,,
- 12 -
' ~`
~ J ~
1046824
the fabricated article makes it possible to form~la porous structure wherein
i`
a number of finer pores are densely formed throughout the surface and
- interior of the fabricated article.
The resulting electrophotographic recording material can be used
as such for various applications connected with electrophotographic recording
on one or both surfaces thereof, and if desired, it can be laminated on a
suitable substrate. Suitable substrates are shaped articles of thermo-
plastic resins including an electrically conductive substance for controlling
the amount of charge. ~-
According to still another aspect of this invention, therefore,
there is provided an electrophotogPaphic record-ing material consisting of
an electrophotographic recording layer comprising the above melt shaped
hlend(s) and (2) a layer for controlling the
, . .
~ .
,~ .
.
~-.
v
~i,
':
- 13 _
Bl ~
. . . . .
1046824
amount of charge comprising a thermoplastic substance contain-
ing an electrically conductive substance.
The laminate-type recording material of this inven-
tion permits a proper control of the amount of charge On the
surface of the recording layer (1) when electrophotographic
recording is performed on the surface of the recording layer
(1). Also, the light decay characteristics of the recording
material can be bettered, and the electric charge is prevented
from remaining on the surface of the recording layer (1).
The thermoplastic resin to be used for forming the
charge controlling layer (2) may be at least one of those used
for forming the recording layer (1), and the same or different
in kind.
The e~ectrically conductive substance is one having
the property of transporting electric charge by the conduction
of electrons or ions, and can be used in the form of powder or
liquid.
Examples of the electrically conductive substances are
metal powders such as carbon powder, aluminum powder, iron
powder, nickel powder, or copper powder; various inorganic
salts such as sodium chloride, potassium chloride, or ammonium
chloride; metal oxide powders such as iron oxide or manganese
oxide; non-ionic polymeric electrolytes such as polyvinyl
alcohol, polyethylene oxide, polyacrylamide, or polyvinyl
pyrrolidine, anionic polymeric electrolytes such as polyacrylic
acid, polyvinyl sulfonate, inorganic polyphosphonate, or organic
polyphosphonate esters; cationic polymeric electrolytes such as
polyethylene imine, poly-N-methyl-4-vinyl pyridium chloride,
; poly-2-methacryloxyethyl trimethyl ammonium chloride, or
-14 -
.
1046824
polyglycidyl tributyl phosphonium chloride; and ionic electri- - -
cally conductive substances such as electrically conductive
oligomers.
The amount of the electrically conductive substance
is suitably 0.1 to 50 parts by weight, most suitably 1 t~ 30
parts by weight, per 100 parts by weight of the thermoplastic
resin used for producing the charge control layer (2). If the
amount exceeds 50 parts by weight, the amount of charge on the
surface of the recording layer tends to decrease during elec-
trophotographic recording, and the decay of the potential by
light is not sufficient, which in turn may cause the resulting
recorded image to lose its clearness. If the amount is less
than 0.1 part by weight, the amount of charge on the surface
of the recording material becomes excessive during electro-
photographic recording, and the light decay of the potential
is not sufficient. This results in residual charges and con-
sequently the formation of fog on the recorded imagesO
The formation of the charge control layer (2) from
the thermoplastic resin and the electricaIly conductive sub-
stance can be accomplished by the various fabricating methods
used to form the recor~ing layer (1).
r` The form of the charge control layer (2) can be
changed according to the recording layer (1), and may be a
film, sheet, plate, rod, tube~ or any other desired shape.
The lamination of the charge control layer (2) and
the recording layer (1) can be performed by any desired methods,
such as a method using an adhesive, a method involving heat
; bonding, a method comprising forming one of the two layers in
advance and laminating it as the other layer is being prepared,
` -15-
.~ .
1046~Z4
or a method involving forming both layers simultaneously in a unitary
structure.
The thickness of the recording layer (1) is 5 to 30 microns,
preferably 10 to 20 microns. The thickness of the charge control layer
(2) consisting of the thermoplastic resin and the electrically conductive
substance is suitable 30 to 1000 microns, more suitably 50 to 100 microns.
The electrophotographic recording materials of this invention
described above can be used widely for recording by various electrophot~-
graphic methods as, for example, an electrophotographic copying paper, a
master sheet, or an electrophotographic recording drum, etc.
The following examples further illustrate the present invention.
In these examples, all parts are by weight.
Example 1
; 300 parts of zinc oxide powder was added to 1,2 liters of an
~- aqueous solution of Rose Bengal in a concentration of 1 x 10 mol/liter,
and the mixture was stirred for 2 hours at room temperature. The resulting
~; suspension was allowed to stand for 2 hours, and the zinc oxide powder to
the surface of which the Rose Bengal had been absorbed was dried for 24 hours
:
by hot air at 100C., followed by coarsely pulveriiing in a mortar. It was
further pulverized in a ball mill for 3 hours to form a fine powder of zinc
oxide having a particle diameter
.
.: .
_ 16 -
'!~
~'
~046824
distributed within the range of 0.3 to 1 micron.
It was determined from the visible absorption spectrum -
that the amount of the Rose Bengal adsorbed to the surface of
that zinc oxide powder was 5 x 10 mol per gram of the zinc
oxide powder.
300 Parts of the zinc oxide powder having the Rose
Bengal adsorbed to its surface and 100 parts of high density
polyethylene were kneaded in a Bumbury mixer for 1 hour at
180 C., and then the kneaded mixture was subjected to calender
rolls at 170 C. to form a paper-like film having a thickness
of 80 microns.
The film so obtained was u~ed for copying an image
on both surface using an electrophotographic recording apparatus
The copied images had superior clearness and resolving power
and good sensitivity to red, blue and black colours.
~easurement of the electrophotographic characteris-
~ tics showed that the resulting film permits a higher potential
i charge and a greater speed of light decay of charging immedia-
- tely after exposure to light than a conventional electrophoto-
graphic recording paper does.
ample 2
300 ~arts of titanium oxide was added to 1.2 liters
of a mixed solution consisting of water, ethanol, and 1 x 10
mol/liter each of Rose Bengal, phthalic anhydride and pyrene.
The mixture was stirred for 1 hour at room temperature, and
- centrifugalized to separate a titanium oxide powder to which
surface had been adsorbed the Rose Bengal, phthalic anhydride
and pyrene. The titanium oxide powder was dried in hot air at
60 C. for 24 hours, coarsely pulverized in a pulverizer, and
-17
~046824
then pulverized in a ball mill for 3 hours to form a fine
powder of titanium oxide having a particle diameter distributed
within the range of 0.5 to 1 micron.
100 Parts of high density polyethylene, 40 parts of
the titanium oxide powder obtained above, and 240 parts of
the zinc oxide powder having Rose Bengal adsorbed to its
surface obtained in the same way as in Example 1 were kneaded
in a ball mill for 3 hours. The kneaded mixture was subjected
to a calender roll for 20 minutes at 150 C. to form a sheet
1 mm thick. The sheet was pressed for 20 minutes at 150 C.
using a hot press to form a sheet having a thickness of 700
microns.
The sheet was maintained at 130 C., and stretched
successively in the longitudinal direction and in the trans-
verse direction to 3 times the original dimension in each
direction to form a paper-like film having a thickness of 60
microns and an apparent density of 20 g/cm3.
Images obtained on the f;lm using an electrophoto-
graphic recording apparatus had superior clearness and re-
solving power.
Example 3
10 Parts of a solution of 3 parts of Rose Bengal and
3 parts of phthalic anhydride in 100 parts of ethanol was
mixed with 700 parts of a powder in zinc oxide in a supermixer
at room temperature for 5 minutes~ thereby to cause the Rose
`: ~
` Bengal and phthalic anhydride to be adsorbed to the surface
of the zinc oxide powder. Then, 100 parts of the zinc oxide
powder having the Rose Bengal and phthalic anhydride adsorbed
to its surface, 40 parts of high density polyethylene powder
-18 -
1046824
: and 0~4 part of zinc stearate were placed in a supermixer,
and mixed for ~ minutes at room temperatureO The mixture
was subj~cted to a kneading roll and kneaded for 1~ minutes
at 150Co The kneaded mixtur~ was formed into a 1.0 mm thick
sheet-like article at 1~0C~ using a hot pressO
The sheet-like article was maintained at 130C., and
simultaneously stretched both in the longitudinal and trans-
verse directions to 4 times the origin~l dimension in each
direction.
1OD The electrophotographic recQrding material so ob-
tained was a 60 micron thick sheet-like fabricated article
consisting of zinc oxide powder having Rose Bangal and phthalic
anhydride adsorbed to its surface, zinc stearate and high
density polyethyleneO
The electrophotographic recording material was
i~ tested for electrophotographic characteristics using an elec-
trostatic copying paper tester (product of Eawaguchi Electric
Works, Ltdo)~ and it was found that this recording material
~ had excellent light decay propertiesO
; 20 Furthermore, this material was used to perform static
recording on both surfaces using an electrophotographic re-
cording apparatusO The recorded images had superior clearness
and resolving power, and showed superior sensitivity to red,
1 black, and blue colorsO
25 Example 4
400 Parts of a powder of cadmium sulfide was added
to an ethanol solution of 1 x 10 2 mol/liter of pyrene, and the
mixture was stirred for 1 hour at room temperature, followed
by stan~ing for 2 hoursO Then, the cadmium sulfide powder
~ Iq_
~046824
having the pyrene adsorbed to its surface was separated. 400
parts of the cadmium sulfide powder having the pyrene adsorbed
to its surface, 100 parts of polystyrene, and 0.4 part of
lead palmitate were placed in a supermixer, and mixed for 5
minutes at room temperature. The mixture was kneaded by a
kneading roll and rolled into a sheet form. The sheet-like
article was cut into granules.
The granules were extruded through an extruder
having an annular die with an inside diameter of 200 mm fitted
thereto to form a tubular sheet. The sheet was cut open to
form a 80 micron thick sheet-like fabricated article.
Electrophotographic recording was performed on both
surfaces of the sheet-like article using an electrophotographic
recording apparatus. The electrophotographic material obtained
above was found to have superior light decay characteristics,
l and be free from residual potential, and the resulting re-
;~ corded images had superior propertiesO
ExamPle 5
100 Parts of a powder of titanium oxide having Rose
Bengal, phthalic anhydride and pyrene adsorbed to its surface
which was obtained in the same way as in ~xample 3, 40 parts
of a powder of high density polyethylene and 0.4 part of zinc
oleate were mixed, and kneaded on a kneading roll for 15
minutes at 150 C. The kneaded mixture was subjected to a
calender roll, and rolled at 170 C. to form a 30 micron thick
sheet-like fabricated article.
Electrophotographic recording was performed on both
~` surfaces of the resulting electrophotographic recording material.
The images recorded were clear, and free from fog.
-20-
. ~ :
1046824
E~xample 6
~ 10 Parts of a solution of 5 parts of Rose Bengal
; and 5 part of phthalic anhy~ride in ]00 parts of ethanol was
mixed with 700 parts of a powder of zinc oxide in a super-
mixer for 5 minutes at room temperature to cause the Rose
Bengal and phthalic anhydride to be adsorbed to the surface
,~ of the zinc oxide powder~ 70 parts of the zinc oxide powder
~; having the Rose Bengal and phthalic anhy~ride adsorbed to its
surface, 30 parts of a powder of high density polyethylene,
and 0.3 part of zinc stearate were placed in a supermixer,
and mixed at room temperature for 5 minutes. The mixture was
kneaded on a kneading roll at 1~0C. for 1~ minutes. The
kneaded mixture was formed into a 003 mm thick sheet-like
- article using a hot press at 150C.
~, 15 On the other hand, 100 parts of a powder of high
ensity polyethylene and 25 parts of a powder of carbon were
mixed at room temperature for 5 minutes in a supermixer to
disperse these materials uniformly. The mixture was kneaded
on a kneading roll at 160Co for 15 minutes, and then formed
, 20 into a sheet-like material having a thickness of 1.3 mm using
;~ a hot press at 150C.
The two sheet-like articles obtained above were
superimposed, and bonded by a heat press at 150C. to form a
laminate sheet having a thickness of 1.5 mm.
~ 25 The lamin~te sheet was maintained at 132C., and
.~ .
stretched biaxially at the same time in the longitudinal and -
transverse directions to 4 times the original dimension in
each direction.
~' ~he resulting electrophotographic recording material
, i;
~ ~ -al-.
. .
~.
10468Z4
was a laminate consisting of a 20 micron thick sheet-like
article as a recording layer consisting of the zinc oxide
powder having the Rose Bengal anA phthalic anhydride adsorbed
thereto, zinc stearate and high density polyethylene, and a
80 micron thick sheet-like article consisting of the high
density polyethylene and carbon powder.
The recording material had superior bending strength,
tear strength, and other mechanical strength characteristics
The recording material was sub~ected to a copying
test using an electrophotographic copying machineO It was
found that the images obtained had superior clearness and
resolving power and superior sensitivity to red, blue, and
black colors, and were free from fog.
The electrophotographic recording material was -
further subjected to an electrostatic copying paper test onan electrostatic copying paper tester (product of Kawaguchi
~lectric Works, Ltd.~, and it was found that the material
exhibited superior light decay characteristics and permitted
no residual potentialO
~xample 7
10 Parts of a solution of 4 parts of pyrene in 100
parts of ethanol was mixed with 800 parts of a powder of
cadmium sulfide in a supermixer for 10 minutes at room tem-
perature to cause the pyrene to be aAsorbed to the surface of
the cadmium sulfide powder.
70 Parts of the cadmium sulfide powder having the
pyrene adsorbed to its surface, ~0 parts of polystyrene ~nd
0O3 part of barium linolate were placed in a supermixer, and
mixed at room temperature for 5 minutes, and then kneaded into
"''
~046824
a sheet form on a kneading roll at room temp~rature for 5
minutes. The kneaded sheet was cut into granules.
On the other hand, 100 parts of high density pol~-
ethylene and 2 parts of poly-N-methyl-4-vinylpyridium chloride
were placed in a supermi~er and mixed for 5 minutes at room
temperature, and the mixture w~s kneaded on a kneading roll
into a sheet formO The sheet was cut into granulesO
These granules were extruded through a three~layer
; extruder including annular dies the largest of which had an
inside diameter of 200 mm, to form a three~layered laminate
con$isting of a unitary structure of an interlayer of an
annular article consisting of the polyethylene and poly-N-
s methyl-4-vinylpyridium chloride, and outer layers of an annular
article consisting of the polyetyrene, the cadmium sulfide
j 15 powder h~ving the pyrene adsorbed to its surface, and barium
,~ linolate on both sides of the first-mentioned annular article.
; The resulting unitary annular structure was cut open to form
a sheet. The thickness of each of the outer layers was 15
; microns, and the thickness of the central layer was 80 micronsO
; The electrophotographic recording material so ob-
tained was subjected to a copyin~ test on an electrophoto-
graphic copying machine. Very clear recorded images were
obtained on both surfaces of the materialO
~ Exa~le 8
i 25 10 Parts of a solution o~ 3 parts of pyrene in 100
parts of ethanol was mixed with 700 parts of a powder of
i zinc oxide in a supermixer for ~ minutes at room temperature,
,:! thereby to cause the pyrene to be adeorbed to the surface of
the zinc oxide powderO
-- ~3--
10468Z4
70 Parts ol the zinc oxide powder having the pyrene
adsorbed to its surface, 30 parts of a powder of polypropylene.
~nd 30 parts of clay (having a particle ~iameter of 1.5 microns)
were placed in a su~ermixer, and mixed for ~ minutes at room
temperature. The mixture was kneaded on a kneading roll for
15 minutes at 180C., an~ then formed into a 0.1 mn thick sheet
using a hot press at 180C.
~lectrophotographic recording was performed on both
surfaces of the resulting sheet on a commercially available
electrophotographic copying apparatus. It was found that the
sheet had superior light decay characteristics, and the re- -
sulting recorded images were free from fogO
Examination of the recorde~ sheet by a scanning
electron microscope showed that a toner was fixed to the clay
powder exposed on the surface of the sheet, and therefore the
fixation of the toner was improvedO ~he toner was not removed
even when the surface of the recorded image was rubbed with a
finger.
,~ ExamPle 9
A 1 mm thicX sheet-like fabricated article was pre-
pared in the same way as in Example 8. The article was then
maintained at 140C., and biaxially stretched simultaneously
in the longitudinal and transverse directions to 3 times the
original length in each directionO The resultant stretched
sheet had a thickness of 0015 and a high degree of non-trans-
. parencyO Examination of the sheet by a scanning electron
microscope showed that a porous multilayered structure was
formed in the sheet, and a great deal of the clay pow~er was
exposed on the surface of the sheet. Thus, in the recorded
;
- ,~y _
B
, . .
..~
10468Z4
surface, a toner was fixed to the clay ~o~der so exposedO When
electrophotographic recording was performed on both surfaces
of the sheet using an electrophotographic copying apparatus,
the sheet had superior light decay properties, and gave recorded
images of superior quality.
~ urthermore, the sheet permitted writing or printing,
and had high mechanical strengths such as tensile strength or
impact strengthO
Example 10
106.2 g of Rose Bengal and 9O0 g of phthalic anhydride
were dissolved in 500 mlO of ethanol, and 20 Kg of a powder of
zinc oxide was added to the resulting solution7 ~he mixture
was stirred for 45 minutes at room temperature using a mixing
stirrer. Then, the resulting mixture was mixed with 66 Kg of
high density polyethylene and 100 g of a lubricant, and dried
in air at 70Co for 1 hour. The resulting mixture was kneaded -
for 15 minutes at 160C. using a roll kneader, and then
granulated by an extrusion molding machine~ The resulting
granular product was put into an extrusion molding machine
having a film-forming die fitted to its tip, and extruded at
210C. at a rate of 30 Kg/hr to form a film having a thickness
of 80 microns.
~ he resulting film was subaected to the irradiation
of ~-rays generated from Co-60 (3000 Curie) in an atmosphere
of air at room temperature in a total dose of 1 Mrad at a dose
rate of 1 x 105 radO/h`rO
Electrophotographic recording was performed on the
re6ulting irradiated film by a ~et-type electrophotographic
copying apparatus. Clear recorded images having a high image
' ~ 0~S--
~,
density and being free from fog of toner could be obtained~
Furthermore, the recorded images had superior sensitivity to
blue, red, and black colors. -
Furthermore, the irradiated f;lm was tested for elec-
trophotographic characteristics using an electrostatic copying
paper tester (product of Kawaguchi Electric Works, Ltd.; Model
SP~428). The results are shown in Table 1. It is seen from
the results shown in Table 1 that the resulting f;lm had superior
surface charging property by corona discharge, retention of
surface potential in dark places, and decay or surface poten-
tial upon exposure to light.
For comparison, the same 80 micron thick film extruded
through a film_forming die as prepared above except that it was
i not subjected to the irradiation of ionizing radioactive rays;~ was tested for electrophotographic properties using the same
electrostatic copying paper tester used above. The results -
are also shown in Table 1. It is seen from Table 1 that the
;~ tested properties of the comparison film were inferior to those
~ of the film subjected to the irradiation of ionizing radioac-
,:j ' :,-
tive rays.
Table 1
ExamPle 10 ComParison
V5 1440 75
V10 -1400 -600
(v -v12)/v10 95 74
; ~1/2 o.6 1.3
.. ~ .
-26-
10468Z4
The items v5~ v10~ V1o~V12/V10~ ~1/2 and E10
present the following.
V5: Surface potential (volts) measured 5 seconds after the ini-
tiation of corona discharge at -6Kv.
v10: Surface potential (volts) measured after standing for 5 sec-
onds in a dark place following the stopping of discharge.
(v10-vl2)/vlO: Light decay rate (%) measured after 2 seconds from
the initiation of intermittent exposure to 200 lux t~ngsten-fila_ent lamp
17 cycles/sec.
; 10 1/2: Half life (seconds) of the surface potential under the above
exposure conditions.
E1o: Amountlof exposure (lux.sec) required to reduce the residual
surface potential to 10%~,of v10 after initiation of exposure under the above
~ exposing conditions.
,j ExamPle 11
,~, A 80 micron thick f;lm extruded from a film-forming die of an
~ extrusion molding machine in the same way as in Example 10 was subjected to
;, the irradiation of electron beams in an atmosphere of air at room temperature
in a total dose of 2 Mrad using a 2 meV electron beam accelerator.
S Electrophotographic recording was performed on the resulting f;lm
using an electrophotographic copying machine. Recorded images having a high
image density and being free from fog of toner could be obtained.
Example 12
~, A 80 micron thick film extruded from a film-forming die of an ex-
trusion molding machine in the same way as in Example 10 was subjected to the
~.,
irradiation of ionizing radiant rays in a total dose of 10 erg/g in an atmos-
- phere of air at room temperature. The radiant rays were obtained by imping-
` ing electron beams generated by a 2 MeV electrQ~h beam accelerator against
a lead plate having a thickness of 1.5 mm.
-27-
,~`. .
1046824
Electrophotographic recording was peformed on the resulting ir-
radiated film using an electrophotographic cop~ing apparatus. Recorded
images having a high image denisty and being free from fog of toner could
be obtained.
The irradiated film was tested for electrophotographic properties
using the same electrostatic copying paper tester as used in Example 10. The
film exhibited substantially the same surface charging property, retention
of surface potential in a dark place and decay of surface potential upon
exposure to light.
ExamPle 13
100 Parts of~a powder of high density polyethylene, 5 parts of an
ethylene/vinyl acetate copolymer, 20 parts of a styrene/methyl methacrylate
copolymer, 10 parts of polyethylene oxide, and 50 parts of powdery diatom-
aceous earth were kneaded on a kneading roll for 20 minutes at 150 C., and
the kneaded mixture was formed into a 0.5 mm thick sheet by a calender roll.
The sheet obtained was maintained at 120C., and biaxially stre-
tched to 3.0 times the original dimension simultaneously both in the long-
itudinal and transverse directions using a tenter stretching machine.
Microscopic examination of the stretched sheet showed that a porus
structure composed of fine and dense pores was formed, and very thin layers
of porous structures were superimp ed. The resulting sheet was white and
non-transparent and had printability and graphic property comparable to those
of paper. The sheet also exhibited superior tensile strength, tear strength
and bending strength.
On the other hand, 2 parts of Rose Bengal and 2 parts of phthalic
anydride we~e- dissolved in 100 parts of ethanol. 10 parts of the resulting
solution was mixed with 1000 parts of a powder of 7inc oxide in a pulverizer
for 5 minutes at room temperature, to cause the Rose Bengal and phthalic an-
hydride to be adsorbed to the surface of the zinc oxide powder.
-28_
~` 1046824
Then, the zinc oxide powder having the Rose Bengal and phthalic
anhydride adsorbed thereto was sprayed on both surfaces of the above sheet-
like material re-heated to 140C. in a thickness of about 10 microns, and
the sheet was pressed by a hot press to adhere the zinc oxide powder hav-
ing the Rose Bengal, and phthalic anhydride adsorbed thereto, to the surfaces
in a layer.
Electrophotographic recording was performed on both surfaces of
the resulting recording material using an electrophotographic copying ap-
paratus. The recorded images formed on both surfaces had superior clearness
and resolving power, and good sensiti~ity to red, blue and black colors.
The recording material was further subjected to an electrostatic
:.
copying paper test using an electrostatic photographic paper tester (product
~ of Kawaguchi Electric Works, Ltd.), and it was found that the recording
y material had superior light decay properties, and no residual potential
was observed.
,
ExamPle 14
50 Part~ of high density polyethylene, 50 parts of low density
polyethylene, 30 parts of an ethylene/vinyl acetate copolymer, 15 parts
of a phenoxy resin, 10 parts of aluminum powder, 5 parts of calcium car~
bonate powder, and 30 parts of powdery diatomaceous earth were kneaded on
a kn~ading roll for 15 minutes at 160C., and the kneaded mixture was
subjected to a calender roll to form a sheet having a thickness of 0.5 mm.
Then, the sheet was cooled to room temperature, and then heated to 110 C.
at which temperature the sheet was stretched biaxially at the same time to
2.5 times the original dimension both in the longitudinal and transverse
directions by a tenter stretching machine.
The stretched sheet so obtained included a laminate of a multipli-
city of thin layers of porous structure, as determined by a microscopic
photograph. The stretched sheet was shite and non-transparent, and had
-29-
,
~o46824
superior tensile strength, tear stren~th and bending strength as well as good
printability and graphic properties.
10 Parts of a solution of 4 parts of pyrene in 100 parts of
ethanol was mixed with 800 parts of a powder of cadmium sulfide in a super-
mixer at room temperature for 10 minutes to cause the pyrene to be adsorbed to
the surface of the cadmium sulfide powder. Then, the cadmium sulfide powder
was dried in a drier held at 100C., and pulverized by a pulverizer.
The cadmium sulfide powder having the pyrène adsorbed thereto was
sprayed in a thickness of about 10 microns on the above sheet, and subjected
to a hot press heated at 114C. thereby to adhere the cadmium sulfide powder
having the pyrene adsorbed thereto, to the surface in a layer.
One surface of the resulting electrophotographic recording
material was subjected to a copying test using an electrophotographic copying
apparatus, Recorded images having superior clearness and resolving power
and being free from fog were obtainedO
The recording material was also subjected to an electrostatic
copying test, and it was found that the material had superior light decay
characteristics, and no residual potential was observedO
Example 15
10 Parts of a solution of 4 parts of Rose Bengal and 4 parts of
phthalic anhydride in 100 parts of ethanol was mixed with 1000 parts of a
powder of zinc oxide in a supermixer at room temperature for 5 minutes to
cause the Rose Bengal and phthalic anhydride to be adsorbed to the surface of
the zinc oxide powerO 100 Parts of this zinc oxide powder and 40 parts of a
powder of high density polyethylene were placed in a supermixer, and mixed
at room temperature for 5 minutes.
The mixture was kneaded on a kneading roll at 160C. for 15 min-
utes, and then subjected to a hot press at 150C. to form a sheet-like
material having a thickness of 0O3 mm.
3Q On the other hand, 100 parts of a powder of high density poly-
ethylene and 25 parts of a powder of carbon were mixed in a supermixer at room
;
- 30 -
'
. . . ~
~04~;824
temperature for 5 minutes to disperse the high density polyethylene powder
and the carbon fiber lm;fonmly.
The mixture was kneaded on a kneading roll at 160C. for 15 minutes
and then subjected to a hot press at 150C. to form a sheet-like material
having a thickness of 1.3 mm.
The two sheet-like materials fonmed in the above manners were
superimposed, and bonded by a heat press heated at 150C. to form a laminate
sheet having a thickness of 1.5 mm.
The laminate sheet was maintained at 132C., and simultaneously
stretched in the longitudinal and transverse directions to 4 times the
or~ginal ~imension in each direction.
!~ The resulting electrophotographic recording material consisted of
a 20 micron thick sheet-like material as a recording layer consisting of
the high density polyethylene and the zinc oxide powder having the Rose
Bengal and phthalic anhydride adsorbed to its surface, and an 80 micron
thick sheet-like material consisting of the high density polyethylene and
the carbon powder.
Electrophotographic recording was perfonmed on the resulting
electrophotographic recording material using an electrophotographic copy-
ing apparatus. Recorded images of good quality were fonmed on the surface
of the sheet-like material as a recording layer.
The electrophotographic material was subjected to an electrostatic
; copying paper test using an electrostatic copying paper tester (the product
of Kawaguchi Electric Works, Ltd.). The recording material exhibited super-
ior light decay properties.
Example 16
300 Parts of titanium oxide was added to 1.2 liters of a mixed
solution consisting of water, ethanol, and 1 x 10 4 mol/liter each of Rose
-31-
-
10468Z4
Bengal, phthalic anhydride and pyrene, and the mixture was stirred at room
temperature for 1 hour to thereby cause the Rose Bengal, phthalic anhydride
and pyrene to be adsorbed to the surface of the titanium oxide. The titan-
ium oxide powder so obtained was separated by centrifugation, and dried in
hot air at 60 C. for 24 hours, followed by coarsely pulverizing the powder
in a pulverizer, and then in a ball mill for 3 hours. There was obtained
a fine powder of titanium oxide having a particle diameter distributed within
the range of 0.5 to I micron.
; 100 Parts of high density polyethylene and the titanium oxide
10 powder were granulated on a granulating machine.
` A uniform mixture of lOO parts of a polyamide resin and 2 parts -
of a non-ionic polymeric electrolyte of the polyethlene oxide type was gran-
ulated in a granulating machine.
Each of the granulated products was placed in each of the cylinders
of a multilayer extruder, to form a two-layered nnitary structure consisting
of an annular molded product consisting of 100 parts of the high density
polyethylene and the titanium oxide powder and an annular molded product
consisting of the polyamide resin and the non-ionic polymeric electrolyte.
The two-layered structure was cut open into a sheet form. The thickness of
; 20 th mo~ded product consisting of the high density polyethylene and the tit-
,
anium oxide powder was 15 microns~ and the thickness of the other layer was
75 microns.
The resulting electrophotographic recording material so obtained
was subjected to a copying test using an electrophotographic copying machine.
Recorded images of good quality were obtained on both surfaces.
- Example 17
400 Parts of a powder of cadmium sulfide was added to an ethanol
solution containing`1 x 10- mol/liter of pyrene, and the mixture was stirred
~, :
-32-
,
1046~24
for 1 hour at room temperature. The mixture was then allowed to stand for
2 hours, and then the cadmiun sulfide powder having the pyrene adsorbed
thereto was separated. 400 Parts of this pyrene-adsorbed cadmium sulfide
powder and 100 parts of polystyrene were mixed in a supermixer at room temp-
erature for S minutes, and kneaded on a kneading roll to form a sheet. The
sheet was cut into granules.
100 Parts of polypropylene and 2 parts of poly-N-methyl-4-vinyl-
pyridium chloride were mixed in a supermixer at room temperature for 5
minutes, and kneaded on a kneading roll to form a sheet. The sheet was cut
into granules.
These granulated products were extruded through a three-layer
extruder having annular dies having a maximNm inside diameter of 200 mm, to
form a three-layered unitary laminate consisting of an interlayer consisting
of the polypropylene and the poly-N-methyl-4-vinylpyridium chloride and
outer layers con~isting of the polystyrene, and the cadmium sulfide powder
having the pyrene a &ered to its surfaceO The laminate was cut open into
a sheet form. The thickness of the interlayer was 60 microns, and the thick-
ness of each of the outer layers was 15 microns.
The resulting electrophotographic recor~;ng material was subjected
to a copying test using an electrophotographic copying machine, and recorded
images of good quality were obtained on both surfaces of the recording mat-
erial.
; -33-
