Note: Descriptions are shown in the official language in which they were submitted.
~l9-A
Several ~ethods are known for the correctiun of typed
errors. The most common method9 other than using rubber erasers,
is the masking method whereby the erroneous image is overstruck
using a white transfer composition which transfers -to the surface
of the erroneous image and blends with the ~hite color of the
paper to mask the erroneous image ~rom view. Therea~ter the
correct image is typed over the masked image. The masking method -
~is unsatisfac-tory in cases where the copy paper is other than
white and a~so in cases where the copy paper or sheet is highly
lQ translucent or is transparent. Also in cases where the copy
sheet is reproduced by methods su-oh as infrared duplication9 the
masked erroneous image may be duplicated on the copy together
with the correct image as an illegible combined image.
Another method proposed years ago in Baldwin U.S. Patent
1,183~424 and more recently in Korb et al UOS. Patent 3,724~633
(IBM) relates to the use of an adhesive ribbon to pick erroneous
typed images from a copy sheet. The method is in current
commercial use and is similar -to the masking method to the extent
that the erroneous image is overstruck using the appropriate
type key. However, instead of interposing a ribbon carrying a
transferable masking coating, one interposes a ribbon carrying a
sticky adhesive coating, similar to Scotch tape. The sticky
ribbon is retained spaced from the copy sheet to be corrected
~xcept i~ Lmpressed areafi which adhere to the errone~us image and
lift the erroneous image from the copy sheet when typing pressure
is released. Thereafter the correct image is -typed in place of
the removed image. Preferably this method is used in
associatio~ ~ith imaging compositions which are dry and ;~
substantially free of oils and dissolved dyes which can migrate
into the copy paper and stain the paper ~ibers.
While such adhesive correction ribbons are in current
commercial use, they do present important problems. Such adhesive
;, . .
~19-A
ribbons must be mounted on specia~spools and tensioned and moved
using special mechanlsms which must be built into the typewriter
in addition to the spools and mechanisms present in every
typewriter for the support and movement of the imaging ribbon.
Thus a special typewriter is required. Also, it is not possible
to use such adhesive coa-tings on con~rentional spli-t correction
ribbons in place of the masking coating, such as in the ribbons
of U.S. Patent 3t664,869, because it is not possible to evenly
wind a ribbon on a spool if one-half the width of the ribbon is
sticky and the other half is not~ Also, the sticky half o~ the
ribbon will tend to stick to the conventional ribbon guides, the
uneven amount of tension required to pull the sticky and non-
sticky halves of the ribbon from the spool will cause breakage
of the ribbon, and unless the ribbon is rewound perfectly even
on the take-up spool, the sticky half of the ribbon will overlap - -
with portions of the imaging half of the ribbon and will pull
the latter from the foundation when the ribbon travel is reversed
for reuse. ~ ;
Finally~ it is not possible to use such sticky adhesive
coatings on correction t~bs or sheets of the type used ~or masking
compositions. If the sticky coating is placed against an imaged
copy sheet, as done with masking tabs and sheets, the sticky
coating will adhere to the copy sheet and will pick off ~11 of
the images which it contacts rather than selectively picking o~f
the erroneous image.
It is the principal object of the present invention to
provide a novel correction element carrying a latent adhesive
coating which is not sticky to the touch and will not adhere to
itself but which is capable of being rendered sticky and adhesi~e
by the application of imaging pressure thereto, such as typing
pressure.
It is another obJect o~ this invention to provide
- 2 -
~35~
cooperative elements adapted Eor cooperate use, one element co~prising a
pressure-sensitive ~ransfer element carrying a transfer composition and the
other element comprising a correctlon element having a latent adhesive
composition adapted to remove images formed from such transfer composition
; under the effects of typing pressure.
It is still another object of this invention to provide a novel
split imaging ribbon, one-half the width of ~hich is coated with a special
imaging composition and the o~her half width o which is coated wi~h a
complementary latent adhesive composition adapted to remove images produced
with said imaging composition from a copy sheet under the effects o typing
; pressure.
According to the present invention thereare provided latent adhesive ~ ;
pressure-sensitive elements comprising a flexible foundation supporting a
latent adhesive layer comprising at least about 10% by weight of a soft,
pressure-flowable adhesive resin and at least about 5% by weight of a
particulate, inert, non-adhesive surface material containing at least about
10% of the weight thereof in the form of large particles having a greater
thickness than the thickness of said adhesive layer, said adhesive resin being
present adjacent said foundation and said large particles of surface material
projecting beyond the surface of said layer and providing a barrier stratum
which is substantially non-adhesive to the touch, said pressure-flowable
adhesive resin3 at ambient temperatures, being capable of flowing through
said barrier stratum under the effects of a~plied pressure to render the
surface of said layer adhesive in impressed areas.
In another aspect, the invention provides process for producing
latent adhesive pressure-sensitive elements comprising the steps of producing
a liquid composition comprising at least 10% by weight of the solids content
as a soft, pressure-flowable adhesive resin, and a~ least 5% by weight of
the solids content as an inert, non-adhesive, particulate surface material, ;`
applying said liquid composition to a flexible foundation, and causing it to
solidify to form a latent adhesive layer in which said aclhesive resin is
present adjacent said foundation and at least lO% o the weight of said surface
_
~t~
material projects beyond the surface of said layer and provides a barri~r
stratum which is substantially non-adhesive to the touch but which is
penetrable by said flowable adh~sive resin, at ambient temperatures, under
the effects of applied pressure.
It is a preferred embodiment of the presenlt invention to provide
latent adhesive correction materials which are suff:iciently transulcent or
transparen~ so that an erroneous image to be remoYed thereby can be viewed
therethrough by the typis~ to insure proper alignmen~ during the co:rrection
process.
These and other objects and advantages of the present invention will
be apparent to those skilled in the art in the light of the present disclosure
including the drawing, in which:
Figure 1 is a diagrammatic cross-section, to an enlarged scale, of .
an imaged copy sheet and a correction element superposed under the effect of
typing pressure,
Figure 2 corresponds to Figure 1 but shows the sheets separated
after the release of the typing pressure, the impressed center images
remaining adhered to the correction element after having been lifted off the
copy sheet,
Figure 3 is a plan view of a section of a split imaging-correction
ribbon produced according to one embodiment of this invention~
Figure 4 is a diagrammatic plan view of a word on a copy
''.
3~
.. , :
919-A
sheet containing an erroneous letter "m", and a correction tab,
produced accordingr to ano-ther embodiment of this invention, held
in position o~er the erroneous image preparatory to the
application of typing pressure, and
FIG. 5 corresponds to FIG. 4, but shows the elements
separated after the application of typing pressure, the erroneous
image "m" being removed from the copy sheet and being adhered to
the underside of the correction tab.
The obJects and advantages o~ the present invention are
aceomplished by means of our discoveryithat novel flexible sheet
materials having latent pressure-adhesive properties at ambient
temperatures for certain imaging compositions can be produced by
applying a single layer containing at least 10% by weight of a
normally adhesive soft resinous material to a flexible foundation,
said layer also containing an inert, particulate surface material
which is not stiGky or adhesive to the touch but which is capable
of being displaced, penetrated or otherwise combined with and
dominated by the adhesive material under ~he effects of applied
pressure. Thus the coated sheet material has a latent adhesive
surface which is not sticky or adhesive to the touch or under
normal handling pressures but which is capable of becoming sticky
or adhesive at ambient temperatures in desired areas by the
application o~ i.maging pressures, such as typing pressures, to
such areas The present materials preferably are produced as
continuous sheet materials which subsequently are cut into
sheet lengths, ribbons, tapes 9 tabs or other SiZ8S depending
upon the manner in which the materials are to be used.
The latent adhesive correction materials of the present
invzntion are produced by the application of a single l~yer to
a ~lexible foundation,said layer containing both the normally
tacky soft resinous adhesive base ma-terial and the non-sticky
surface material and having the ability of drying or solidifying
'9l9~ 5~
as a layer in ~Yhich the exposed surface consists primarily of the
particulate non-sticky surface material which prevents the
underlying latent adhesive material from coming into contact with
the hands or with other sheets in the absence o:~ a~plied imaging
pressure. Under the effects of such pressure, the latent adhesive
material is ~orced around or through the surface material ~or
adherence to the sur~ace against which it is impressed.
The drawing illustrates the use of the present sheet
materials as image correction materials in dif~erent forms -~
Referring to the drawing, FIG. 1 illustrates an imaged
copy sheet 10 and a pressure~adhesive correction ~hee~ 20
superposed under the pressure of a type bar 30. The copy sheet 10 ~ -
consists of a flexible paper or plastic film sheet 11 Car~Jing
solid images 12 and 13 which have been typed thereon using a
film- or paper-base typewriter ribbon coated with a solvent-applied
solid dry transfer composition. The correction sheet 20 consists
of a ~lexible paper or plastic ~ilm sheet 21 carrying a pressure-
adhesive layer 22. The pressure-adhesive layer 22 might be
te~med a stratified layer in which the soft resinous adhesive
base material is present primarily in a base stratum adjacent the
flexible ~ounda-tion 21 while the surface stratum consists
primarily of protrusions o~ non-tacky surface material such as
inert resinous rnicrospheres.
The type bar ~0 carries an image type face corresponding
to the erroneous center image 13 to be removed from the copy
sheet 10. U~der activation of the appropriate type key9 bar 30
strikes the rear sur~ace o~ correction sheet 20 and produces an
imagewise pressure contac-t between sheets 20 and 10, ~aid contact
being limited to the area o~ center image 13 and the corresponding
~0 area of the pressure-adhesive layer 22~ Some o~ the so~t tacky
adhesive o~ the base stratum is compressed and exuded through or
beyond the no~-tacky surface stratum in ~he impressed area to
-- 5 ~
3919-A
provide a sticky adheslve surface in pressure contact wi~h the
cente~image 13. In the non-impressed areas, -the other images 12
are in normal surface contact with the non-tacky surface stratum
and do not adhere thereto.
When impact pressure is relaxed by withdrawal of the
type bar 30 and the sheets 10 and 20 are se]parated, the center
image 13 remains bonded to the correction layer 22 on the
correction sheet 20 and is cleanly lifted off the copy sheet 10,
as illustrated by image 13X in FIG. 2 of the~drawing. The copy
~heet 10 can now be reimaged in the appropriate area to
substitute a correct image for the erroneous image 13 which has
been removed.
FIG. 3 illustrates a split imaging-correction ribbon 35
having lengthwise stripes of pressure-adhesi~e correction
composition 31 and complementary pressure-transferable imaging
composition 32 which is specially ~ormulated so as to be cleanly
removable from a copy sheet by means of said correction
composition. The ribbon 35 has a ~lexible foundation, preferably
a plastic ~ilm, and the stripes 31 and 32 pre~erably are applied
to the foundation as solutions using appropriate volatile solvents
and appropriate printing rollers. On drying by evaporation of the
volatile solvent, the correction stripe ~1 ~orms a non-tacky
surface stratum of non-tacky inert surface particles 3~.
Alte~natively, one or both of the stripes 31 and 32 may be
produced on a separate foundation and cut and adhered on a common
foundation to produce the structure illustrated by FIG. 3.
FIGS. 4 and 5 illustrate the use of a correction sheet
40 in tab form to remo~e an incorrect image 51 from a copy sheet
50 carrying correct images 52~ The tab 40 comprise~ a clear,
flexible plastic film ~oundation 41 and the correction layer on
the ~nderside thereo~ contains clean adhesive and projecting,
non-tacky inert surface particles 42 whereby the tab 40 is
3919-A
sufficiently translucent or transparent that the underlying
image 51 can be clearly viewed therethrough to insure proper
positioning of the tab 40 against the image 51.
When the "m" key is activated on thle -typewriter, the
tab 40 is pressed imagewise against the imalge 51 an~ adheres to
and lifts the image 51 from the copy sheet 50 when the tab 40
is removed from the copy shee-t 5Q. The othler correct images 52
remain on the copy sheet 50.
As mentioned supra, the pressure-adhesive correction
materials of the present invention comprise a ~lexible
foundatiQn such as paper or plastic film carrying a unitary
latent adhesive correction layer. The foundation preferably is
one which does not absorb the correction layer to any
substantial degree. Thus, less porous papers and treated papers
such as glassine paper are preferred while normally porous
papers having a resinous barrier layer supporting the correction
layer are also suitable. Clear plastic ~ilms are preferred for
some applications because of their strength, pressure-
deformability and transparency and impervious nature. Resinous
undercoatings may be used to bond the correction layer to the ~ -
film foundation where necessary. Preferred films are polyethyl-
ene terephthalate polyester, polyethylene, polypropylene,
cellulose acetate, nylon, and the like9 depending upon whether
sheets3 ribbons or tabs are being produced. Generally the
paper foundations are preferred for correction material sold in
continuou~ tape form in a conventional correction tape dispenser ~;
provided with means ~or ~acilitating the tearing of desired
lengths from the continuous tape since paper tears more easily
than plastic filmsO Howe~er9 plastic film foundations may also
be used for continuous tapes pro~ided that a suitable cutter is
used on the dispenser, such as a metallic tearing means. On the
other hand, plastic films are ge~erally preferred as fou~ldations
- 7 -
~919-A i{~
for correction ma-terial sold and used wlthout tearing, i.e. as
ribbons, individual full sheets or tab sheets, or the like, where
stren~-th and durability are i~portant.
According -to a preferred embodiment, the present
correction materials are provided with a cushioning foundation
which has a thickness grea-ter -than normally used to produce
pressure-sensitive transfer sheets. The ob~ject is to accomplish
a result which is to be avoided with ordinary transfer sheets~
i.e. a broadening of the impact pressure whereby the area of
the pressure-adhesive composition which is activa-ted against
the image to be corrected by removal is greater in all
directions than the area of the image itself~ This insures
overlapping coverage of the image to be removed and complete
removal thereof. Such cushioning foundations include paper or
plastic film of increased thickness, i.e. ~rom 1.5 to 5 mils, ~,
laminates of paper and/or plastic films united by a resinous
bonding layer, paper and/or plastic films having a soft resinous
binder layer either between the film and the pressure-adhesiYe
correction layer or as a back:coating on the film7 or the li~e.
This result is also accomplished to some extent by the softp
pressure-flowable properties of the pressure adhesi~e composition
itselP.
The correction composition is based upon a conventional
soft resinous binder material which contains at least about 10%
by weight, based upon the total weight of the adhesive layer, of
one or more soft, pressure flowable, tacky or sticky adhesive
resins. The preferred adhesives are the viscous liquid
elastomers such as the polybutenes, polyisobutylenes,
polyisoprenes, polyvinyl ethers, polybutadiene and rubbery
copolymers of butadiene with acrylonitrile, styrene a~d other
monomers3 rosin esters, and the like. Most preferred are the
Indopol polybutenes having mean molecular weights ranging from
T~ t~k
-- 8
319-A ~ 5
A 320 for Indopol L-lO to 2150 for Indopol H-l900, and the ~ist~ne
isobutylene polymers having mean molecular weights of ~rom 8700
to 11,700.
In addi-tion to the highly adhesive resinous material, the
present compositions preferably contain~ as an extender or
diluent, a synthetic resinous binder material or a wax binder
material ~hich is substantially less adhesive than the adhesive
resinous material, i.e. it is not sticky or adhesive or is less
sticky or adhesive than -the adhesive resin and is compatible
-therewith~ at least at elevated temperatures, to provide a blend
having the desired degree o~ tack or adheslv~ess. Preferred
extenders include resins such as the polyole~ins including
polyethylene and polypropylene~ polystyrene, polyvinyl butyrate,
nylon~ acrylic polymers, and the like, and waxes such as carnauba,
montan, microcrystalline paraffi~, beeswax, and the like. Most
preferred for solvent-applied compositions are the polyeth~lene
.~ .: . . . .
emulsions such as Polyethylene A-C 6 which has a mean molecular
weight of 2000 and a softening point of about 220 F. I~ the
case oX solvent-applied compositions, the extender resin or wax
must be soluble in the same volatile solvent used to dissolve the
adhesive resinous binder material9 at least at elevated
temperatures. In the case o~ hot-melt compositions, the wax
extender and adhesi~e resinous binder material must be meltable
together at elavated temperatures.
The present latent-adhesive resinous compositions also
contain a substantial amount, at least about lO~o by weight based
upon the total solids content, of a non-sticky inert surface
material which is a solid which is incompatible with the adhesive
resin and with the extender wax or resin, i~ present, and is
insoluble in the ~olatile solvent used as the coa-ting vehicle ~r
has a melting point in excess of the tempe~u~e of the hot-melt
composition~ The surface material contains at least 10% by
rc~clevr~rk
_ g _
s~
~919-A
weight of the par-ticles thereof in the form o~ particles having
a size at least slightl~ grea-ter than the thickness of the dried
adhesive correction layer in areas between said large particles,
whereby said particles project above -the general sur~aoe of the
correction layer and assist in preventing the adhesive
correction layer from s-ticking to the fingers or to other sheets
in the absence of imaging pressure. Sin¢e the present correction
layers generally have a mean thickness o~ from abou-t ~ to 10
points (i.e. from 0.0002 to 0.001 inch) in areas between the
projecting particles, then the surface material contains at
least 10% and up to 100~6 by weight of the particles thereof in
the form of particles having a minim~ size ranging from about
6 microns for a 2 point coating up to about 26 microns for a
10 point coating. The maximum particle size for a correction
layer of any thickness appears to be about three times the mean
thickness of the layer, i.e. from about 13 microns ~or a 2 point
coating up to about 75 microns for a 10 point coating. Obviously
the presence o~ small amounts of particles of larger size, or
o~ agglomerates of particles having a larger size can be
tolerated, and in fact most surface materials generally consist
of a mixture o~ particles of various sizes even though they
have a specifi.ed average particle size.
The pre~erred surface materials are spheres o~ polymers
having an average particle size of from about 4 to 25 microns,
at least loYo by weight of the particles of which have a diameter
greater than the thickness o~ the adhesive layer in which they
are used. Some such spheres also have a lower specific gravi-ty
than -the resinous binder material, i.e. the adhesive resin or
combina-tion of adhesive resin and extender resin or wax, and
this appears to assist their formation of a surface stratum.
The present inert polymer spheres retain their spherical shape
when dispersed in the solution or hot-melt composition containing
-- 10 --
.
i~l9~
the adhesive binder material and at leas-t 1(3% by wei~ht of the
par-ticles extend above the adhesive stra-t~ of -the dr~ layer due
to their size. Other smaller par-ticles may come to the surface
of -the layer during d~ing or cooling of the composition on its
flexible foundation or are left a-t the surface of the dry layer
when the solvent is evaporated or the composition cools and -the
resin binder shrinks on solidifioation~ The most preferred
polymer sphere composition is Polymis ~A 12 which co~prises
polyethylene spheres having an average sphere size of 12 microns
(4.8 points), a melting point Gf 284 F, a specifio gravity of
0.99 and containing about 40~0 by weight of larger spheres. Also
suitable are Fluon~F 170 which co~prises polytetrafluoroethylene
spheres having an average sphere size of less than 5 microns
(2 points), a melting point greater than 600 F and a speoific
gravity of 2.28, and Polymist 5 which is similar to Fluon F 170
and has an average sphere size of 4 microns (1.6 points) and a
melting point o~ about 660 F. A11 of these materials, which
contain at least 10% by weight of particles greater than the
average size, are commercially available as dry powders which
have a whitish color and are readily dispers.ible in the solution
of -the correction composition. Generally, it ~ppears that even
the smaller polymer spheres are supported on each other in the
pressure-adhesive layer so that at least a substantial number of
the smaller spheres extend beyond the surface of the adhesive
stratum and assist the larger polymer spheres in spacing the
latter from contact with the hands or with adjacent sheets.
The weight ratio between the polymer spheres and the total
solid composition may be varied depending upon the size and weight
of the polymer spheres, the thickness of the correction layer,
the degree o~ tackiness of the resinous binder material and the
degree of pressure-sensitivity desired. In general~ the polymer
spheres co~prise from about 5Yo to about 50% by~eight of the total
~ T~le~ ~
- 11
`919~ $ 5
composi-tion, the preferred range being from abou-t 10% to about 30%
by weight. A thick correc^tion :layer can con-ta;Ln a greater ratio
of adhesive resin and ext~nder to inert non~tacky particles -than
a thinner correction layer since both have the same sur~ace area
-to be protected.
In place o~ the preferred polymer spheres, it is also
possible to use as surface ma-terials similar amounts of other
inert ~inely-divided, particulate materials which are non-sticky
to the touch and which have the size requireaments discussed
supra so as to ~orm a projecting sur~ace stratum when -the
correction composition is applied to a flexible foundatiQn and
dried. Suitable are glass beads, silica spheres, hydra-ted
amorphous silica particles, starch particles, clay particles~
and the like. The weight ratio o ~eavier surface materials
obviously will be on the high end of -the a~orementioned rati
while the weight ratio of lighter surface materials will be on
the low end o~ such ratios.
The thickness o~ the correction coating and/or of the
foundation of the present invention is important in insuring its
per~ormance in accomplishing the complete removal of erroneous
images. The coating and/or the ~oundation must be sufficiently
thick that the adhesive binder is capable of being exuded beyond
the non-tacky sur~ace material and of spreading at least slightly
so as to overlap the erroneous image in all directions to insure
~ts complete coverage and removal as discussed supra in
connection with cushioning foundations. In this regard, it is
also pre~erred to support the correction layer on a ~oundation
which has good pressure de~ormability such as nylon/ polypropylene
or polye-thylene. The thickness range will vary somewhat
depending upon the smoothness and absorbency of the pressure-
de~ormable foundation but in general the thickness ranges from a
minimum thickness of abou-t 2 points (4 pounds per re~n of 3~00
- 12 -
~919-A ~ S ~
sq.f-t.~ -to a maximl~ thickness of about 10 point.s (20 pounds per
ream). The preferred thickness range i5 bet;ween 3 and 6 points.
The pressure-sensitive -transfer ma-terials used according
-to the present invention are preferably formulated so as to
provide the best possible results when used in combination wi-th
the present correction materials, i.e. so as to be complementary
thereto. It should be understood that the present correction
materials are not suitable for the complete removal of all types
of images. For instance, images formed on paper from liquid
typewri-ter ribbon ink stain the paper fibers and cannot be
completely removed. Also, irnages ~ormed on paper or other
receptive support f`rom oil-containing hot-melt wax compositions
such as by means o~ wax carbon paper or ribbon cannot be removed
completely because the wax imaging composition has poor cohesion
and ~ractures internally during removal rather than picking off
as a whole and/or the oil present integrates with the paper and
carries coloring matter therein.
The preferred pressure-sensitive transfer compositions
used herein are solvent-applied compositions having a film-
forming or resinous binder material and pigment and which are dry,cohesi~e and essentially free of soluble dyes which can migra-te
into a paper support and for irremovable stains on the paper
fibers. A preferred transfer composition contains some oil to
improve the ~rangibility o~ the resînous binder material but also
contains a sufficien-t amount o~ clay or other oil-absorben-t
porous ~iller to bind the oil within the composition and~reven-t
it from quickly migrating into the paper ~oundation. ;~
Suitable film-fo~ming or resinous binder materials include
cellulosic film-formers such as ethyl cellulose and cellulose
acetate-butyrate, vinyl resins such as polyvinyl acetate ~nd
styrene, acrylic resins such as ethyl acrylate and methyl
methacrylate, chlorinated rubber, terpene resins, and the like.
- 13 - ;
~19-A ~ 5 ~
Improved frangibility is provided by us:ing mixtures of such
resins which are soluble in a common solvent bu-t which are
incompatible with each in the c~mounts used so that they separate
from each other upon evaporation of -the solvent, thus preven-ting
excessively high internal bonding therebetween and promoting
frangibilityO In -this connec-tion reference is made to Canadian
Patent 866,710 which discloses suitable incompatible resinous
binder mixtures. Generally, the resinous hinder material
comprises from 15% to 50~o by weight of the transfer compositionO
The pigment may be any conventional solid colorant such
as carbon black, milori blue, magnetic iron oxide, or the like,
generally in an amount ranging between about 10% -to 40% by weight
of the total dry composition.
Oils, oleaginous semi-solid materials or waxes mav be
added -to improve the ~rangibility of the transfer composition
provided that sufficien-t porous filler is included to absorb any
such materials which tend to migrate quickly fro~ the -transfer
composition into the copy paper, as disoussed supra. Thus9
liquids such as refined rapeseed oil, mineral oil, butyl stearate,
semi-solids such as lanolin and hydrogenated oils, and waxes such
as paraffin and carnauba can be incorporated in amounts ranging
from 0% up to about 40% provided that porous fillers such as clay,
talc 9 calcium carbonate, diatomaceous ear-th, silica or starch
preferably are included in substantially similar amounts to absorb
such materials.
The following examples are given as illus-trative and
should not be considered limitative.
A latent adhesive correc-tion element is produced by
co~ting a web of 2.5 mils thick polyethylene terephthalate
polyes-ter film with about 24 po~ds per ream (~300 sq.ft.) of
the following composition:
- 14 -
919
In~redierlts l~
Polyethylene AC 6 7
Polybu-tene H 300 7
Stabelite Ester 10 3.5
Polymist A 12 7
Naphtholi-te solvent 75.5
The Polyethylene AC 6 ex-tender (registered trademar~ for
polyethylene resin having a mean molecular weight of 2000),
Polybutene H 300 adhesive resin (registered trademark for
adhesive bu-tene elastomer) and Stabelite Ester 10 adhesive resin
~registered trademark for a glycerol ester of hydrogenated rosin)
were dissolved in 25 parts of the Naphtholite solvent (regis-tered
trademark for mineral spirits) at a temperature of 220 F, using
agitation~ to form a clear solution. The rest of -the solvent is
then added and the solution is cooled to room temperature.
During cooling, the solution passes through a cloud point and ?
turns white and increases in viscosity due to at least a portion
of the polyethylene resin coming out of solution. Next the
Polymist A 12 (registered trademark for polyethylene resin
spheres) is added to the solution with agitation to form a
uniform mixture which is coated onto the polyester film.
~ The coated film is heated to a temperature of abou-t
; 185 F to evaporate the solvent and ~orm a dry layer. The coated
film has a frosted appearance but is translucent and transpicuous,
i~e. images positioned against the coated film are clearly
legible therethrough. The dry layer has a weight of about 6 ~`
pounds per ream (about 3 points) and has a smooth~ non-sticky
surface feel. Referring to FIG~ 1 of -the drawing, -the formed
correction ~lement 20 has a plastic film foundation 21 supporting
the dr~ correction layer 22.
Example 2 ;~
A latent adhesive correction element is produced by
- 15 -
'' ,
coating a web of 2.0 mil polyethylene -tereph-thalate polyes-ter
fllm Wi~l about 11 pounds per ream (3300 sq.f-t.) of the following
hot-melt composi-tion:
~ Parts~ Jei~ht
Microcrystalline paraffin wax 3.5
Carnauba wax 1.5
Stabelite Ester 10 0.5
Polybutene resin 1.0
Polymist A 12 2O0
The wax extenders and adhesive resins are heated together
at a temperature of about 160 F to form a uniform hot melt~ Then
the Polymist powder spheres are added and mixed uniformly therewith
to form a coatable hot-melt composition which is coated onto the
polyester film as a uniform layer having a thickness o~ about 6
points and cooled to form the pressure-adhesive correction element.
According to another embodiment of the present correction
process 3 the correction elements used may be produced by
conventional encapsulation techniques whereby the pressure-
flowable adhesive resin is the water-non-miscible, emulsifiable
phase and the surface material is the io~izable hydrophilic
colloid material which deposits around the adhesive r~sin in the
form of pressure-rupturable capsules. Reference is made herein to
U.S.Patent 2,800,457 relating to suitable encapsulatlon techniques
and to U~S.Patent 23986,477 relating to suitable pressure-adhesive
encapsulated materials. Such materials are non-adhesive to the
touch, due to the presence of the capsules which provide a non-
adhesive surface casing enclosing the adhesive resin. In areas
where the capsules are ruptured b~y typing pressure, the pressure-
flowable adhesive resin is exposed for pressure-contact with the
~0 surface of the image to be removed. The degree o~ adhesion
between -the image and its support is much weaker than the degree
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~
of adhesion bet~leen the :lmage an~ the pressure-flowable adhesive
res.in, ~hereby the image remains adhered to the latter ~ld
separates cleanly from the su~)port or copy sheet when the
correction elemen-t is separated from the la-tterJ
Ex~
~ pressure-sensitive transf`er elemen-t which is
compl.ementary to the correc-tion elements o~ Examples 1 and 2 is
produced by coating a web of 0.5 mil high density polyethylene
film with the followirlg composition:
~a:~
Refined rapeseed oîl 5
Carbon black powder 6
Clay 4
Wetting agent 0.6
Polyvinyl acetate
Polystyrene 4
Methyl ethyl ketone 79~L~ ~ -
The coated film is heated in a drying tunnel to evaporate :~
the solvent and form a dry pressure-transferable imaging layer
having a dry weight of about 2 pounds per ream. The ooated film :
can be cut into sheet leng-ths and/or ribbon widths~
The coated ~ilm is used in the same marmer as conventional
carbon papers or typewriter ribbons to ~orm images on ordinary
copy paper but such images can be cleanly and completely removed
:` from the eopy paper by means of the present correction elements .
such as those produced accordirlg to Example 1 supra.
Referring to FIGS. 1 and 2 of the drawin~, the imaged copy
, paper 10, having a paper foundation 11 supporting the images 12
and 13 typed by means of the transfer elemen-t of Example~, i5
positioned against the correction elemen-t 20 of Example 1 and the
erroneous image 13 to be removed is overs-truck with type bar 30
corresponding -to center image 13, the correction element 20 being
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... . . . . . .
919-A ~ S
posi-tioned there`bet~een w:i-th i-ts latent aclhesive layer 2~ in
surface contact with images 12 and 13. The impac-t of the type
bar 30 forees the adhesive ma-terial within Layer 22 into
pressure contact with erroneous image 13 to fo~n an adhesive
bond therebe-tween, while the non-impressed areas of layer 22
retain a non-sticky surface which does no-t adhere to the images
12 in contaot therewith. On separation of the sheets 10 and
20, the image 1~ is completely and cleanly removed from copy
sheet 10 and remains bonded to correction sheet 20 as removed
image 13X, as sho~m by FIG. 2. Copy sheet 10 can be recompleted
by typing a correc-t image in place of the removed image 13X using
the same imaging composition.
As illustrated by FIG. 3~ a so-called split correction
ribbon 35 can be prepared according to the present invention by
applying adjacent stripes o~ the presen-t complementary correction
composition ~1 and imaging composition 32 to a common foundation~
Gorrection composition 31 presents a non-s-ticky surface comprising
the Polymist polymer spheres 33 so that the ribbon 35 can be
wound on a spool in conventional manner similar to an~ other
typewriter ribbon without the correction layer adhering to the
back surface of the foundation, Also the split ribbon 35 can be
fed within conventional ribbon guides without sticking thereto.
This is also true of the present correction ribbons which carry
a full coating of latent adhesive correction composition,
If desired, the present correction materials may be
produced by printing the correction composition onto the continuous
founda-tion web in -the form of spaced stripes or as discontinuous
spaced applications so that the web may be cut into ribbons,
tapesS ta~ sheets ~r other desired shapes without cutting through
~0 the pressure-adhesive layer. This is particularly advan;,ageous
in the case of several plies of superposed webs or sheets which
are cut simultaneously into tabs. If a cu-t is made through the
---B919-A ~ 5l~
latent adhesive layer, the cut edges o~ the tabs stick together
and the tabs are di~icult -to separa-te ~rom each o-ther. However,
if at leas-t one edge of each -tab is free of -the latent adhes:ive
composition, -the -tabs can be separated from each other along that
edge.
~ ariations and modifications may be made within the scope
of the claims and portions of -the improvem~n-ts may be used
without o-thers.
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