Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
WO90/11183 .. PCT/CA9~/00102
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Titl~: R~US~BL~ ~RITI~G ~ATERr~L
D~CRIPTION OF ~HE INVENTION: :
The descrip~ion o ~he current invention is
divided into two par~s, speci~ically a) a background of
the invention and b) a detailed description. ::
~ACKGROUND OY T~E INV~TION:
A num~er of reusable wxiting surfaces have been de~eloped
; over ~he centuries. Xn their earliest form, such surfaces
: l0 ha~e ~een as primitive a~ stick scratchings on a dirt
surace. In their recent form, reusable writing surfaces
ha~e been daveloped from a variety of technologies ~nd
include ceramic, plastic, magnetic and glass surfaces.
Over the past years, we have seen the ~raditiQnal
blac:kboard ;and chalk replaced by ~hese new rçusable
~surfaces. T~he mos~ familiar of the~e i~ probably the
white:board" ~hirh is written upon using special ink or
"dry" mar~ing pens. On an indlvidual u~e basis, small
slates have been increasingly repl:aced with plastic coated
l~write-bn/wipe-off~ memo boards which al~o require a
specialized::ink~marker. :In using either of these writing
materials, writLng is confined to the us~e of specialized
implements~whi~ch:usually~provide a relatively wid~:marking
line.
The curre~t in~ention allows the user to utilix~ a thin-
line writing implement such as the rommon ball point pen,
for:clean and clear copy in:a restri~ted space and allo~s
large ~ ounts:~:of writing,:drawing or calculating to occur
in a~ larger amount o~f ~pace. Further,~ unlike the white
boaxd or w~ite-on/wipe-of-f board, inks ~applied to the
~ current invention do not readi~y smear, bu~ rather perf~rm
:~ a~ a "temporarily permanent" medium. "Temporarily
~ permanent" is here defined to mean writing which i~ not
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e~sily removed by brushing against, as is the case with
white ~oards, nor easily removed by touching wi~h a damp
finger, hand or other item, as is the case with write-
on/wipe of~ ~oards; but rather, applied ink may be wip~d
across without smearing or other detrimental effect and
will remain on the surf ace over time. Removal of inks
from the invention can, however, be accomplished by the
use of moderate rubbing, stroking, or wiping wi~h a
comm:on, dry matexial such as, but not lin~ited to, cloth,
tissues, paper napkins and toweling.
Although the current in~ention could be used as a dra~ting
film, and is a laminate whose surface is a plastic, ~he
invention differs greatly from existing drafting films.
For example, drafting film, such as ~Mylar~ is marked upon
~: lS by a pen. the inX for which is generally confined to
. permanent or tusch in~s, Once dry, these inks can be
removed f~om the film by~the use of friction era~ers. In
r~gard t~:~ the current:inv~ntion, inks deposited on the
laminated~màterial can be easily removed by the use of
20~standard, dry wiping materials; erasing is not required or
; ;: recommended.
:: In contrast~with draftin~ films:/ it~has; been found that
: markings ~ uncoated or untreated plastic sur~aces~ will
usually rub~:off, peQl or~flake. Poor a&esion or surface
tension is normally ~he problem here. ~Consequently, it
could~be argued that polypropylene, the material used~as:
the first layer of the laminate natllrally~pro~id~s the
:~ 'chara~te istics o'f iink acceptancè ànd eas~ ink:removal~
This is, however unk:rue. Inks do not easily adhere to
plastics unless the:plas~ics~ar~ treat:ed, and~further,~ink
remo~al can be difficult as pens:can scratch the surface
of the plastic material, leaving residual ink behind.
: In su~mary, the laminated product per~its data,
~ information or drawings to be recorded pe~manently, yet
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pe~mits changes to be mad~ readily to such data,
information or drawings if the need arises. Noreover, the
now permits the use of standard ball point pens rather
than the use of special markar pens previously required.
And the laminate also allows relati~ely easy removal of
these inks by use o standard dry cl~th wipi~g. It
b~comes evident that the present invention has numerous
end-us~ applica~ions which are limi.ted only by the
imagination. Potential u~s includer but are not limited
to, memo boards, address books, planning calendars,
scheduling boards, game boards, score cards, editing
overlays, identification labels and other innumerabl0
- uses. Products can be utilized in home, office,
industrial and recreational pursuits.
:
Con~equen~ly it is the object of this in~ention to provide
: a wri~ting surface ~hat can easily be written upon by a
wide Yariet~ of writing impIements including, but not
limit~ed to, the common ball-point pen, some fine-line
roll~ing pens, permanen~ markers (with thè exception of
markers ~ho~se inks contain xylene~, dry markers, write-
on~wipe-off markers as well as permanent ink drafting
pens. In other- words, it; is also the ~object of this
: inventio~n to provide~ a writing surace that will
ac~ommodate use by common writing implemen~s, eliminating
2~5 the~need for specialized ~writing ~ools. This~ al1Ows
: graater flexibility in ~he use ~of various~ wri~ing~
:implements and their inks,:these to be:used in~ependently
or in concert with one another.
Another objecti~e of~ this inYention is to provide :a
30~writing ~surface that ~remains :clean during use~ without
significant smearing.
:: Yet a further objective of this invention is to provide a
~: writing surface that is easily cleaned, either in sections
~or aorr~c~ion or chang~s or in to~ality to provide a
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fresh, clean writing surface, e~en if i~ks have been
deposited upon the writing material some time in the past,
and ~o provide this clean ~urface wi~hout any significant
ghosting of past inks.
S~MMARY OF TH~ IMV~NTIO~:
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~his invention relates to a writing sur~ace which can be
written upon with any common ball point p~nr and a ~ariety
of marXers including, but not limited to, permanent
markers, write-on/wipe-off markers, rolling-pen markers
and dry markers, and which can be cleaned away by the use
of standard, dry wiping materials such as tissue, paper
- napkins, toweling, clothr or other such similar material,
allowing the writing material to be reused o~er and over
; again.
BRI~F D~SCRIPTION OF T~ DRAWINGS~
Understanding of ~he invention will be enhanced by
referring to the accompanying drawings in which:
F:igure l depicts a` cross-sectional ~iew of a material
providing a wri~ing surface, in accordance with one
20 ~embodiment of the present invention;
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Fi~ure~ depicts a cross-sectional ~î~w of ~he material
providing a writing ~surface as shown during t~e writing
procass when utilizing a ball poin~ pen;
Figure 3 depicts~a cross-sectional ~iew of a material
providing a writing surface, in accordance'with a further
embodiment of the present~in~ention; and
Figure 4 depi~t~ a cross-sec~ional view of a material
pro~iding a writing surface in accordance with a still
further embodiment of the present in~ention.
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DEST __DI~ SCEIIPTION OF THE INV~WTION:
There is a wlde range o~ materials which can be used to
form the overall laminate or composlte, the different
materials interacting to provide dif~erent properties.
The r~nge of materials which are suitabl~ and their
various general properties will be described initially,
and will then be followed by a number of specific
examples.
Reference is first made to figure 1 of the drawings, which
shows a cross-sectional view of a mat0rial, generally
indicated as 8~ wh~ch provides a writing sur~ace. In its
most basic form, the matexial comprises three primary
layers: a first or upper layer of pol~propylene 12, which
pro~ides the actual wxiting surface; an intermediate layer
of adhesive 14; and a sub-strate or base 16.
The upper layer 12 may be written upon using ink from most
: b~ll point pens, write-on/wipe-off markers, dxy white-
board erasers, some rolling pens, and permanent markers,
: with the exception that inks containing xylene will writ~
~: 20 on ~he material, but canno~ be ea~ily removed. ~he inks
perform, in efisencel as a "temporarily p~rmanent~ medium,
~ : that is the applied~ ink may be wiped across without
:: ~ significant smearing or other detrimental effect and will
remain on the~surface o~er time, tes~ results indicating
that thQ material can:stand up to several hundred use~
~ before deterioration is significant.
: ~ A wide range o polyp~opy~lenes, including some propylene
copolym~rs may be u~ed for: the upper layer 12.
Thicknesses of the polypropylene may ra~ge upwards from
0.2 mils, although thic~nesses above 20mm have been found
to work less effectively. The preferred thickn~ss lies
between .5 and 3.8 mils. The polypropylenes may be
composed of ~ssentially any polypropylene known in the
art, including but not limited to, films which axe
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str~tched, rolled, bi-axially oriented, me}t and ormed,
and/or blown. The pr~ferred use i5 bi-axially oriented
polypropylene. Both low and high densi~y polypropylenes :
may be used, although those with a harder ~urface
gen~rally p~xform better, that is~ they relea~e th~ inks
be~er and do not ind2nt as easily.
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Although polypropylene provides some of the best
charact~ristics for easy removal of inks, as an
independent film, polypropylene will not support the uses
provided by the current invention. Only by enhancement,
refininy and control can po:lypropylene perform as desired
within the composite. Polypropylene films find utility
when supported or lamiinated to another material in order
to accommodate a particular end use. The lamina~e
construction of the current invention provide~ durability
of the:material~and increased longevity of use as compared
to the qu~ick ~deterioration of unsupported:polypropylene.
: Most impoxtantly, the composite provides a specîfic,
esilient writing surface which allows the inks to "set
20 upn or adhere to the fiIm. This is indicated in Figure 2
which shows the spread of the ink~ 6, upon: ~he depression
of the writing material by a pen 4. Because of the nature
: : of the composite, it is theorized that ~he angle of
wettin~ pro~ide~ by this action i~ significantly ralated
: :~ ` 25 to the~ability of ~he~laminate to accept ball point p n
: inks. Or to ~tate it~another way, it is ~he resilience of
;the laminate that provides; ~he proper medium for allowing
the composite to be written upon.
Development of a laminate al~o provides a background
: 30 colour, if desired,: which would facilitate eas~ reading of
the written material. If left clear, though afixed to:a
base ma~erial, the laminate would retain a limited,
although de~irable pr~duct for editing purposes or other
similar uses. And ~inally, the development of a laminate
:~ 35 allow~ a smoother writing surfac~ which acts as a buffer
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between ~he writing sur~ace and the unrelated support
surface, that i~ a t~ble surface, chart surf~ce ox other
such support. This is also important a~ the ~urface layer
o the laminat~ will suffer deterioration wh~n xubbed over
a patterned base or support, the higher areas receiving
more abrasion as tha writing surface is wiped clean.
As an enhancament of the ~asic laminate, polypropylene may
ba modified by the inclusion of friction reducing agents
such as, but not limited to, fatty acid amids, olefins or
sllicon. Such additives migrate to the surface,
continually res~oring the:original surface slip. As a
further ~bodiment, a thin surface layer 10, may also be
added to th~ writing surface of the polypropylene, such
as, but not limited to, a finely di~ided organic material
: 15 or.silicon to decr~ase friction. Use of such a friction
: coating could pxovide good performance in regard to
smoothness and conductivity. The resulting film could
ha~e a mor~ s~able surface without any adverse effec~s on
: appearance or wetting. Antistatic agents could also be
added to help dissipate the static charges of the
~ laminate. This is helpful in th~t charged surfaces can
:: cause resi~tance ;to: the easy removal of inks from the
~` ~ writing surface. St~tic chàrges have:been shown to occur
from environmental conditions or from an unstable mating
of materials within the laminat2.
b
D~pending on the application and speciflc material
construction, a variety of adhesives may be used to form
the in~e~mediate ,layeri 14. Suitable ,adhesives ,can
include, but are not limited to, hard d ~ ing urethane, or
acrylic-based adhesives, soft dryingt pressure sensitive
acrylic or water;based adhesives, or a rubber or
~ubberized adhesive, including hot-melt adhesives. Th~
a~h~si~e may also contain additives such as, but no~
limited to, carbon, lithium and atactic polypxopylene to
~nhance conductivity characteristics. The specific type
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of adhesi~e to be used is dependent upon ~he ~ype o~ base
ma~erial used and the thickness of ~he top lay~r of :~:
polypropylene chosan. Testing has shown that sot,
pr~ssure-sensitive acrylic-based adhesives appear to offer
kh~ b~st per~onmance, closely followed by rubberized
adhesi~es. Hard adhesives will generally only perform
well when combined with a soft base 16. :.
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Althou~h a permanent adhesive i5 preferred, urther ;~
imp~ovement to the adhesive s~ructure i~ recommended. It
is preferred tha~ the underside of the polypropylene ilm,
where i~ is joined to the base 16, be subjected to corona
discharge and that the ba~e material be treated with an
anti-slip agent before they are af~ixed together. This
provides greater stability to the laminate, and mi~igates
: 15 undesired ~hifting, slipping or separa~ion of the various
elements. ~ ~
Use of certain adhesives, such:as for example, urethane
adhesives, requires an~aging or curing time before the
materia1 will work effectively.~ :
: ~ 20 AlInos~ any material can be used :as a support base 16:. The
prefexred material: for forming the base is a vinyl
material with a: thickness o~f hO 10ss than about .5 mils.
Th~ vinyl may be poured, roll~d, blown or lamina~ed, and
additives to i ncrea~e the resilierlGe Inay be added to ::
~: 25 produce a "soft" vinyl. Othsr materials may also be
suitable for use, including, but not limited to, oth~r
: :elastom~r~,~ s~y~en~,~synthetic pap~r suc~ as that sold.
under the tradename "Texoprint~', papex board such as that
: sold-under ~he:~tradena~e "Durobrite", and~etal and hard-
board suc~ as ma~erial sold under the tradename
Masonitell, as well ~s rubber and rubberized materials.
Paper~may be a suitable base only~when used in conjunc~ion
with a ~ery elastic or resilient adhesi~e as otherwise
paper tends to indent koo easily, making removal of the
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inks difficult.
It becomes evident that adhesi~es mus* be balanced wi~h
the base ma~erial to develop a laminate that i5 suitably
functional. Each time one of the material~i used within
S the laminate is changed or modified, the specifics of the
composition need to be rebalanced. If, ~or example, a
relatively soft, spongy material such as blown vinyl
polymer or foam-backed ~inyl is used to form the base, a
hard urethane-based adhesive may be used as khe
intexmediate layer 14 to pro~ide a good smear-proof
writing sur~ace. If such a soft base is combined with a
softer adhesive, the resulting writing ~urface tends to
allow inks to be much moxe easily removed. Yet if
combined with a ~ery soft, thick layer o~ adhesive, this
same foam-backed ~inyI base may result in a surface that
:~ does not ~asily accept ink.
Additional layers:to the laminate may be used to enhance
the utilization of the composite. It has been found that
it may be~suitable to add a conducti~e layer 22 such as
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~20 carbon or foil to the:composite ~o enhance the ease of
:~ erasibility ~for certain:composites. In this case, the use
o~ heat seal 24 would:be:suitable in: the lamination of
: foi-l to the laminate.~ Further, a final:layer of ~hesive
18 could~be added to any of: the developed laminates to
~: 25 allow adhesion of ~he:composite to ~he ~urf~ce of choiceO
: This would a~so require the ~ddition of a r~lease line 20
to facilitate use of the composite as a "self stick~ or
label materiàl. ~ i!
: E~A~pLæ:
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~he~ prQsent invention is further illustrated by the
following examples which are represen~ative of the
:~-- multiple forms the composite can take.
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W09~/111~3 ~ " PCr/C~0/~0102
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1. Upper layer~ l.6 mil polypropylene ~:
Intermediate layer: urethane adhesive (le~s than lmm :-:
thickn~ss)
Ba~e: l5 mil thick foam~b~cked vinyl ~
Suitable for ball point pens and markers. Provides a ::
very smooth wrîting sur~ace.
2. Upper layer: 1 mil polypropylene
Int6rmediate layer: semi~so~t acrylic pressure-
~ensitiv~ adhesive (l mil)
Base layer: 3 mil ~inyl of medium hardness
Suitable ~or ball poink pen and permanent msrkers
:
3. Upper layer: 1.2 mil polypropylene
Intermediate layer: rubberized, soft adhe~ive
:~ Base layer: 2 mil ~lnyl with plasticizers for
softness :
Suitable for ball point pen or markers~ Provides an
easy:ink remov l
4. Upper:layer: 1.2 mil pol~propylene
Intermediate layer: semi-hard, ~crylic re~in (1 mil~
~; 20 Base layex: soft vinyl with plasticizers, approx. lO
mil thick
: Suitable for pen and mar~er use. Easy to erase
5. Upper layer: 1.6 mm polypropylene
Intermediate layer: rubberized adhe~ive 2 mil thick
: 25 Base ~ayer- 20 to 85 point styren~
Suitable for ball-poi~t pen and marker use. Clean
writing surface
~: 6. Upper l~yer: 2,5 mil polypropylene
Inkenmed1ate }ayer: soft, rubberized adhesi~e at l-
. 30 2 mil t~ickne~s
;~: Base layer: 20-85 pt. Duobrike dual direction milled
: board
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Suitable for ball point pen and narrow line markers~ ;
Some indention of ba~e with hea~y handad pen use.
7. Upper layer: 1.6 mil polypropylene ;~
Intermediate layer: so~t synthetic elas~omer solution
applied 1.6 grams p~r meter2
Base layerO Metalixed plastic
Suitable for wide maxkers
8. Upper layer: 1.2 mil polypropyl~ne
In~ermediate layer: semi-hard, high molecular weight
polymeric adhesive
- Base layer: so~t vinyl at 1-2.5 mil ~hickness
Suitable for pen and marker. No~ as easy to erase
9. Upper layer: 1.6 mil polypropy1ene
~ . Intermediate Iayex: semi-soft acrylic pressure-
:~: 1;5 sensitive adhesive 2 mm
Base material: Synth~tic paper such as Texoprint
Sui~able.for pen and marker. Easy to write and erase
lO.~Upper layer: 1.2: to 3.6:mi1~polypropy1ene
Intermediate l~yerO rubberized adh~sivs or hot melt
:~ 20 at 2-3 mil thick ~ : :
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Base Layer o 2 0 pt ~ paper ~ :
; Suitable~for pen~or marker. Heavy pen use can 1eave~
~: indenta~ion
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: 11. Upper layer: 1.6 mil:polypropylene
Inte ~ ediaté" laye~: ~:semi-soft pressure sensi~ive -
a~xylic adhesive~ 2 mil;thick) ~ : ;
~ Base layer: 1 mm~vinyl with mi~imal p1asticizers:~
:~ Additional Adhesive layer: ame as intermedia~e layer :
~ : Further subs~rate:~ 20 to 85:point styrene
:~ 30 Enhanc~d suitability ov~r example 5.
I21 Upper Iayer: l.4 mil polypropylene
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Intermediate layer: pre~sure sensiti~e water base
adheslve
~as~ layex: l mil plasticized vinyl
Additional Adhesi~e layer: same as in~ermediate layer
Further ~ubstrate: release liner
13. Vpper layer: .75 mil polypropylene
Intermediate lay~r: pressure-sensitive acrylic
adhesive (1-2 mil)
Base layer: l mil ~inyl
~0 Further adhesi~e layer: pressure sensitive adhesi~e
(l mil)
~ Conducti~e layer: Foil
~dditional adhesive~layer: same as above
Further sub~trate: any suitable ma~erial
` I5 With excessive amounts of adhesi~e this became
~; a ~pongy ~aterial.
With suitable amoun~s of adhesive~ suitable for
pens and markers.
14. Upper laye~: 1.6 mil polyprop~lene
~;` 20;~ Intermedi~te layer5 Pressure sensitive semi-soft
acrylic adhesive (1-2 mil thick):
~;~ : Base layer: l to:S mil vinyl
dhesi~e layer: Pressure sensitive ac ~ lic adhesi~e
: incorpora~ing carbon particle~
Substrateo A~y suitable material
Suitable ~or pen or marker.
: 15. Upper layer: .75 mil po~ypropylene
Intermediate layer: acry1ic pressure-sensitive
: adhesi~e (l mil) ~ :
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Ba~e layerz 1 mil rubber sheeting
Suitab~e for pen or marker. Yery easy ko erase.
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16. Coiating: Silicon
;~ Upper layer. l.25 mil po1ypropylene
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Adhesive: synthetic rubber hot melt (l mil)
Base layer: 2.5 mil ~inyl with plas~icizers to
"rubberize"
The above descriptions and examples obviously suggest many
possible ~ariations and modification~ of this invention
which would not depart from its spirit and scope. It
should ~e understood, therefore, that the invention is no~
lLmited in its application to the details speci~ically
described o.r illustrated, and that, within the scope of
the claims it may be practised otherwise than as
specifica1ly described or illustrated.
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