CA2128113A1

CA2128113A1 - Photoluminescent retroreflective sheeting

Info

Publication number: CA2128113A1
Application number: CA002128113A
Authority: CA
Inventors: Daniel E. Zampa; Alex A. Szopinski
Original assignee: Individual
Current assignee: Stimsonite Corp
Priority date: 1992-01-16
Filing date: 1993-01-14
Publication date: 1993-07-22
Also published as: TW285650B; NZ246793A; PL171563B1; MX9300209A; AU3436393A; CN1075374A; EP0631670A1; EP0631670A4; WO1993014422A1; IL104366A0; ZA93314B

Abstract

A photoluminescent retroreflective sheeting (10) for use in structures when a power outage occurs. Guidance systems are made from this sheeting to mark exits and escape routes as well as possible hazards and safety devices. The novel sheeting includes photoluminescent (14) properties that glow in the dark as well as retroreflective (12) properties that retroreflect light incident upon the same sheet such that only one sheet has to be used rather than individual sheets with separate properties.

Description

3/1~22 PCT/U~93/00103 2~ l3 ~8C~IPTION

PE~O~IN~C~T_R~TROR~FL~C~ TI~G

T~.CENICbL_~akD
The invention relates generally to a photoluminescent r~troref lective sheet material for use as a guide marker and which has particular utility in buildings when a power outage occurs~ Specifically, the present invention relates to a photoluminescent retroreflective sheeting combining both photoluminescent and retroreflertive, propertieg in a~single product to be u~ed to form a marker 5 ; system to h~lp indicate exits, doorways, hazards,`OSHA
markings, pipe ~arkings~, high voltage areas, fire hoses and èxtinguishers and the like,~when it is dark in the ui1ding,~perhap~ when cau~ed by a power outag~.

20~:B ~ ~O~ND ~F_~R~ 9~
; The~term "~uilding"~as used~throughout this app~iGation:is~intended:~to include any structure su~h as an~aircraft,:~boa`t~or~other moveable and non-moveable-~
conv~n~ional~;structures.~
25~ is well~kn ~ that~within buildings~at night or espe~ial~ly when~the~;power~has::been lost, it is dif~iGult to~ind~ones~way:along~`the;~necessary corridors to the 4uilding~exit~. ~Similarly, in some emergenci~s, the cation~of important:::~ixtur~s such as fire alarms, 30~:~ extin~uishérs,~shut-of~:~valves and the like are difficult to find.~

, WO93~14422 PCT/'US93/00103,~

,., .~ .
~.2~ 2-In the prior art, a photoluminescent material isutilized as a guide for such purposes. The luminous material i attached to doorways, hallways, and the like, : so that in the event of a power outage, the photoluminescent material will glow in the dark and guide a person to an exit'or along a prescribed path. Of course, it is only useful to those individualx in the building that hav~ adjusted their eyes to the darkness.
Fu~ther, the luminescence produced is significantly lost within the first 20 minutes of an "outage." This makes it ~, virtually useless to anyone entering the building after a short period of time.; ~
: The present i~vention overcomes the disadvantag,es of : the prior art by providing a single sh~eting material having~both photoluminescent:and retroreflective properties. The sheèting should eXhibit the same : photoluminescent properties~:as the curren~ product being : used,:and it::has~:significant:retroreflective properties.
Thus it is~an:important object of the present :20~: invention,to:~:provide:a~:photoluminescent retroreflective shéet~material~that~is:desi~gned to pr~vide both photoluminescence~and retroreflection of light.
~m~ It~is~al~o~an-~object~of the~pre~ent invention to provide~;a~ ~ otoluminescent~retroreflective sheeting in :2S~:~;whiGh~ a~phosphorescent::pigment,i~added to the retroræflect~i~ve,~layer., ~ : :
It~Is~a Pu thér;~object o~ the:present invention to prQvide,al;photol~minescent retrore~lective sheet in which he~retroreflective~layer~has cubs corner retroreflectors 30~ èmbossed~on',~th~baekside~thereof and covered by a pr~e~etermined:~ps~tern of:hydrophobic siIica. A
backc-oating contains~the:~phosphorescent pigment and is in con~act with~:the;re~roreflective layer in areas of the pattern~not~covered:by:the hydrophobic silica.

W093~1~22 PCT/US93/00103 -3~

It is yet another object of the present invention to provide a photoluminescent reflective sheet which has a transparent flexible film with retroreflective cube corners formed on the reverse surface th~reof and a clear adhesive with phosphore~cent pigment screen-printed in a pattern and cured on th~ cube corners.
It is believed that the present invention may be utiliz~d with retroreflector sheeting produced in a ~ariety of way~ but will be particularly useful with that ~ 10 re~roreflective sheeting described and claimed in U.S.
:~ Patent No, 4,618,518, issued October 21, 1~86, to Robert M. Pricone, et al. and a~igned to applicants' assignee, the disclosure of which is incorporated by reference.
- ~ Others forms and m~hods of produciny retroreflective ; 15 sheeting include:those of ~'casting'l cube corner elements, such as~disclosed in Rowland U~S. Patents 3,810,804, iscued~May 14, 1974; 3,684,348, issued August 15, 1972;
and~3,689 t 346, issued~Septe~ber 15:, 1972.
Useful apparatus~for~embossing a film to provide cube 2~0 :~corner retroreflecti~e elements is disclosed in Priconet et~al.:~U.5.;~4,601,861,~issued July 22, 1986, commonly assigned. Other~technlques~for:co~pression or ~squential :embosslng are~d~sclosed in;Rowland U.SO 4,244,683, dated Januaxy~13~ 198~
~ Efforts;:h~ve~been~made in the~past to utilize fluorescént~pig~en~d~:materials in con3unction with retror~flective~sheet:mat~ria~ls:of;the cube corner type.
However,~ suah use~of~fluorescent ~ateria~s was intended to ; provide~a~combination:of:~day/night visibility in highway 30::~ signs-~ ~One~example is that found~in Rowland U.S- Patent 3~,830,682~, isæued~August 20,~1g7:4. However, i~ such uses, uniike~:phosphors,:~the~lourescent material would not continue to glow or:provide;light under "darkened"

,.- ~: :: : :

~093/1~2 PCT/US93/00103~

21Z8i~3 4 conditions ~ut instead i5 illuminated by the light of c~rtain wave lengths, ~o as to provide some "daylight"
~isibility to highway signs.
The pr~sent invention utilizes a phosphorescent pigmentation in conjunction with retroreflectiv~ sheet material in a manner which does not materially impede the retroreflecti~e capability o~ the sign when illuminated : either under normal lighting conditions, such as in a building and under hallway lighting lights, nor does it impede the "dark" or night light retroreflective capability when illuminated by a flashlight or other ;~: temporary light source.

: ~ ~MMARY OF T~ INV~NTION
The~presen~: invention~relates to a photoluminescent retroreflective~sheeting~material, which, in one em~oqiment~:co~prises a~first;layer o~ transparent retroreflective~film:~having a~front face and a plurality of~cube cornér~retroreflective :elements formed on at least ~a portion:of;the~revèr~e~or:réar face to retrore~lect light impinging~upon~ he~:front ~ace; a second layer of ;clear~àdhes1~e~is~screen-printed in a~pattèrn and cured on :the~formed~ cube~corner~element~; a third layer o~ opaque ilm:~is~adhered~to~the~;second~layer to ~orm a~r cells; an :25 ~àdhesive~fourth~ ayer~is;~pplied~to the third Iayer for attaching the~ s~eet:material~to:a:~u~strate surface; and a :release linér`is~nor~ally~secured~to~the~dhe ive layer to prevent inadYentent~contact of the adhesi~e la~er wlith a surface.~ pho~phorescent~pigment is cont~in~d in at 30~ least~one:o~ thë~f;lrst,~second:, third or ~ourth layers to ;cause the~sheet~to:~:glow~in the:dark.
:~ In:~a~second; embodiment~the second layer is comprised of hydrophob~ s~i~lica~whlch~el:iminates the ~'air cell".
Other~em~odiments are~disclosed and claimed.

~, :
bdd~Y

~93/14422 PCT/US93/00103 z~ZP~3 R8CRIP~IO~ OF T~ ~RA~I~B
The~e and other obj~cts o~ the present invention will be more fully understood wh~n taken in conjunction with t~e follow~ng detailed description and the attached drawings in which like numerals represent like elements and in which:
FIG. 1 is a first embodiment that illustrates a cross sectional ~iew of photoluminescent retroreflective sheeting o~ the present invention in which clear adhesive ~:~ 10 with a phosphorescent pigment~is screen printed in a : pattern on the retroreflective cube coxners formed on the rear surfa~e:of a tran6parent film;
FIG. 2 is a crosssectional view of a second embodiment of the present invsntion in which the 15~ retroreflective l~ayer o~ film has the cube corners embossed on the rear surface thereof and a hydrophobic ,~ :
~ silic~ pattern i~:applied on the embossed surfaces; a :~ ~ . back~oating with phosphorescent pigment is applied over the: hydrophobic~silica and~ i6 in contact with the 2~0 ~therwise expo6ed~retroreflective cub~ corner elements;
FIG~.~3 i6 a aross-sectional ~iew of a third embodiment of the~ pre6~nt~::invention in~which the retroreflecti~e layer has the aube~corner reflectors on one side thereof and~which layer~al60 contains the phosphorescent pi ~ ent 5~for~enabling~;:the:~sheet:to be~seén when-not illuminated by an~ex~érnal sour~e.~:An adhesi~e layer is applied over the hydrophobio;~6ilica~;layer~and~ ~ osed cuber corner ele~ènt:s,~,and ~ release liner is added to preYent I
accidental:contaGt:of the adhesive with a substrate 0~ surfac~
FIG. 4 is a~;cr~ss-sectional view of yet another embodiment of :the~present invention, in which the retrore~lecti~e layer contains the phosphorescent pigment;
:

:: ` ' : ` :

~ , W093/14422 PC~/USg3/00103~
';,:".. :`
21;28i~ -the hydrophobic silica is ~creened in a pattern over the embos~ed cube corner retroreflectors on the retroreflective layer; a white backcoating is applied to the silica layer and to the exposed cube corner elements, an adhe~ive layer i~s added and a relea~e liner is applied to prevent th~ adhesive from accidentally touching a surface;
FIG 5 is a flow diagram of a process for making one embodiment of the present invention;
FIG 6 is a~flow chart illustrating the process for making the invention~illustra~ed in FIG 2 of the present invention;
FIG 7 is a flsw chart illustrating the process for .
making the embodiment of~FIG 3 of the drawings;
FIG 8 is~a~schematic drawing of the flow chart for making the photoluminescen~ retroreflective sheeting of the~FIG ; 4 embodi~ent; and FIG ~9 is;a~oross-sectional view of another embodiment oP the~ invention in~whi~h~;the phosphorescent pigment is ao~ u tilized;~with~nbéaded~sheetingn~ con aining microspheres to provide retroréfIectivity ~

D~TA~D~DE8CRI~PTION`~OF T~E DRA~IN~8 A~préferred~em~odlment of~the present photoluminescent 5~ retroref1eotlve~ ~ ~ting~is il~lustrated in ~ross-section in~FIG ~ The~sheet comprises~a fir~t layer of transparent~r ~ orè~flective~film~12~that~is form~d gqnerallylin~accordan~e with the method ~nd apparatus dis¢losèd in~the~aforesàid~Pricone U S patent No 4~,4~86,~363 ~ ~ r,~;as;notéd,~other methods of forming a fil~with~aube~;corner~retroref~1ector elemants (or spherical retrorefl-ctors;l nay~be used ~093/~4422 PCT/US93/00103 Z~,,Z~,.

In the preferred form, the film 12 is approximately 0O006-0.008 inches thick and has a plurality of retroreflective corner cube elements 13 e~bossed on the rear side thereof.
It also has a lay~r of clear ~dhesive 1~ containing a phosphor~scent pigment screened in a preselected pattern over certain of the cube corner element~ 13 so as to leave ;: spaces or cells 22. One ~uch adhesive 14 may be that known as Flexcrill GP-2, sold by Air Products, Inc., and applied by screen printing. This is a water based ~ acryclic.
: : The adhesi~e 14 contains a phosphorescent pigment : which may be of a type known as P-1000, sold by Ha~ovia, a division o~ Conrad, Inc..~f Newark, N.J~ and which i5 : 15 commercially a~ailabIe. Other phosphorescent pigments may b~ used. The pigment may be batch mixed with the adhesive 50 as~to constitut~ about 30% by:weight th~reof.
Other adhesives that~ay prove sa~is~actory would be drawn fro~ unpigmented:acrylics~;~urethanes; W curable : 20 ~ 10~%:;solids; the criteri~being:tha~ the adhe~ive bond be~ween~the resin layer~and~bacX~layer b~ flexib}e and be readily-applied~
T~e~transpare~nt~r~troreflective~ilm 12 with t~e clear adhesive~14~and~containinq ~he phosphorescent pigment 5~; thérein~is then~cured:by:heating~or, i~ appropriate, and W~curable,~then~:curing~can:be~acc~lera~ed.
After:~cùring,~an opa ~ e;layer o~ ma erial 16, (such a5 polye~ter,:P~C, or~Mylar), is then applied over the transparent alear:~dhesive:l4 with the phosphorescent 30~ pi~ment~,~to complete~the~"air~' c~lls 22. The air ~ells permit retrore~lectivity to:~be;achieved, as is known in :;: the~art.~ Preferably,~ this layer~1~6 will be of a white color ~o enhance~the brigh~ne~s of ~he phosphorescent :effect7 but~other colors or metallized films may be used.

, WO93/14422 P~CT/US93/00103 Z~Z8i13 -8-An af~hesive fourth layer 18 then may be applied to the white layer I6, enabling the sheeting material to be attfach~d to a surface. A release liner 20 is applied to the adhesive layer 18 to prevent inadvertent contact of the adhesive with a surface until the user is ready to install the heeting.
In the embodlmen~ o~ FIG. l, the retroreflecti~e cells 22 allow the transparent film 12 to be retroreflective and reflect light impinging upon the front surface. The clear adhesive l4 with the phosphorescent pigment allows the strip to g}ow in the dark so that it can be followed by an individual. Thus, such sheeting can be used to form ; guidance~systems that mark exits, doorways, hazards and the like in the case ~f a power outage. When the photaluminescent proper*y~of the sheets fail then the retroreflective~cube corner elements will retroreflect incide~t light,~such~as from a flashlight or the like ~ , , : ~ .
carried by servi~ individuals such as police, fire or utility~department~officia~ls.~
2:b: ~ In FIG. ~2~,~ the~sheeting 24 could be formed of a retroreflective~layer~of~transparent flexible film ~6 with ube~corner retrorePlectivè elements 27 formed on the reverse~side;thereof by embfossing~, to reflect incident light thereon.~ A~h ~ ophobic ~sil~fca layer 28 is screen 25 ~ printed~in~a~pattern~o~er~thè cube corner retroreflective cells~27~ A~clear~water-based~backc~ating 30 is then placed~over`~th~hydrophobic~;s~ilica 28. ~he backcoating containS the~phosphorescent;~pi~ment. ~ whit~ pi~mQnt a ~ esive;~32~;is~1aminated~to the~backcoating 30 for a~taching th~ sheet~to~a~urface. W~hite pi~ment is used tc, enhance~re~lectivity as~well as brightness of the phosphorescént~material.~A~release liner 34ff is laminated ~093/1442~ . P~T/US93/~0103 D 9 .

to the a~hesive to pr~ent the adhesive 32 from inadvertently contacting a surface until the user is ready.
In the embodiment illustrated in FIG. 3, tha retroreflective l~yer 38 also includes the phosphorescent pigment therein. The hydrophobic ~ilica 42 is then screenQd on the cube~corners 40 in a pred~.termined pattern and a white pigm2~ted a~hesive 44 is coated over the hydrophobic sllica pattern. Again, a release liner 46 is laminated to the adhesive 44 to prevent the sheet from inadvertently sticking to a surface until the user is re~dy~for ito Other advan~ag~ouæ uses of the present inventi~n with respect to retrorefleati~e sheeting of other kinds, such : 15 as metallizing~ o~er some:or all of the ref1ector el~ments, also will be recogniz~d.~ Thus, for example, retror~flect~e ~heeting material is disclosed and Martin U.:S.~Patent 4,801,193~may be provided with the :phosphore~cent~pigmentation advantageously employed in the pressnt~invention~
n:the :é ~ odiment illustrated in FIG. 4, the sheet 4B
is again~ormed~o~:a transparent f1exible film 50 ~hat has retroref1ecti~e~:cube~arner~e1ements 52 formed on the re~erse:~;side:~thereof; and~whi~h contains the phosphore~cent ; 25~ pig~ent d~scribed~earlier.~:Again,~a hydrophobic SiliG~ 54 is~scrèened~on~the~cube~Gorner~of th~ translucent refl:ective: flexib~le~:film~50~in a predetermin~d pattern. A
white backcoating~56 as described!earlier is coat~d over :the~hydrophobic~sili~a 54.~ An adhesive layer S8 i~
laminated to;~the:white back:~oating 56 and a release liner 60 is laminatad:to~the~adhesive ~58 to pre~ent the adhesive from~inadvertently~contacting a surface before the user :: desires~

: ::, ~ . . ~, . ::: . :

8~

The method of application and composition of the hy~rophobic silica, ~acXcoating and a~hesi~e as discussed herein may be as disclosed in the aforesaid Pricone et al, U.S. Patent No. 4,618,518.
A process ~or forming the photoluminescent retroreflective sheeting shown in FIG. 1 is illustrated in ;~ FIG. 5. The transparent flexible film may be extruded and have retroreflective cube corner elements embossed or cast on the re~erse side thereof at step 64. At step 68, a clear adhesive containing a phosphorescent piyment is screen printed in a predetermined pattern on the cube ~ corner elements on the reverse or rear side of the flexible : film. At step 70, the adhesive is cured and at step 72 an opaque film, preferably white, is adhered to the adhesive :to form air cells. At step 74, an adhesive layer is added to the film and at step 76 a release layer is laminated to the adhesive~layer~:to pre~ent:the adhesive ~rom adhering to a~surface prior to:the time it;is - ~ :
needed. ~ ~;
20 ~ Fig. 6:illustrat~es the process steps for forming the invention~of~ FIG.~:~2. ;~Again,~in step 1, the transparent f~lexible~film~is~extruded. ~At step 78 retroreflecti~e cube corners~are~:formed~ n:the reverse side by casting or embossing.:~:At~step~82;,~hydrophobic silica is screen 25~ printed~in a~:pat~ern~:~over~the~cube:corn~r elements. At ; step~84,~ the~s~ilica~is~coated with a clear water-based backcoating Gontaining:the~p~osphorescent:pigment. A white (or~other~color)~pigménted~adhesive is applied to the silica~coa~ing:at step 86:and;a release layer is laminated.
30~ to~the~pigmented~adhesive at step 88 ~o pre~ent the : adhesive~from:~:inadvertently~stiGking to a surface.

~ :
: . ::

- Z~

FIG. 7 is a flow chart of the process for ~orming the photoluminescent retroreflectiYe sheeting illustrated in FI~. 3. As can be seen in FI~. 7, the flexible film is extruded and contains the phosphorescent piyment which glows in the dark. The retroreflective cube corner elements are then embossed on the reverse side of the extruded flexible film at step 9~. Hydrophobic silica is : then screen printed on the cube corners in a pr2determined pattern at step 94. A water-based backcoating adhesive is applied to the hydrophobic silica at step 96 and the adhesive coating layer may be cured at step 97. Finally, a :; release liner is laminated to the adhesive at step 98 to prevent the product from sticking to a surface inadvertently.
The flow chart of~FIG. 8 discloses the method of : making~ the sheeting sample illustrated in FIG. 4. Again, at step lOO, the~lexible ~ilm containing the : phosphorescent~pigment is extruded. In step 102 the reverse side of the sheet~is embossed with the cube Gorner 20~ e:l~ments~ In step:~104, the hydrophobic silica is coat~d with a piymented water-bas~d backcoating, pre~erably white.
At step 108 the~1ayer~of adhesive is applied to the backcoating and~in~ætep llO a~release liner i5 laminated to the~adhesive.~ Ag~a~inj~such~liner is use~ to prevent the 25~ adhe;sive~from~:inadvertently~sticking to a surface be~re it is~intende~ o~be~used.:~
SinGe~the~pre~ent film is primarily to be used : indoors~,~additiona1~overlays:or other ultraviolet inhibitorslwhich~he1p~prevent deterioration of outdoor 30~ retrore~f1ective~sheeting may not be necessary~ further reducing:~he~pr~cessing cost.
F~G . : 9 disc1O~es a sample microsphere beaded type : sheet material 13~0 employing the~present invention. The : beàded~sheetin~130~may be~of the type produced by 3M

~: :

W093/14422 PCT/US93/~103~

2i28~13 -12~

Corporation and ~old under the trademark Scotchlite0.
It is believed such material is ~ade in accordance with various 3M patents such as Nos. 2,407,680 and 4,511,210.
In this embodi~ent ~he sheeting comprises a layer of monosphere beads 135 and a transparent layer of resin below which may be a specially reflecting sur~ace 136.
The phosphorescent pigment 134 may be employed in an overlay over the beads, or in the binder layer 137 in which the beads are embedded. In th~ case of so-called high intensity beaded sheets, the phosphorescent pigment ~:: . may be incorporated into the cell walls. A layer of adhesive 138 and a release }iner 139 also may be used.
It will be appreciated from the ~oregoing that,the : present invention pro~ides significant advantages for safety purposes ~in that dual functions can be obtained while:utilizing sheeting haying a high degree of retroreflectivity~and photolumineæcRnce while minimizing the amount of material required ~or each such purpose.
While the invention :has b~en described in connection 20 ~with~a~preferred embodiment,:it~is not intended to limit the~scope of:~the~inve~tion to:the particular form set forth~ but,~on~the~aontrary, it is intended to cover such alternatives~ ::modifications,~and equi~alents as ~ay be included~within~e;spirit and scope of the invention as 25 ~;~dèfined~by the:~appended~cla~ims.

, :

~''blir~Q~

Claims

-13-

1. A phosphorescent and retroreflective sheeting for use in a multi-functional marker for a visual guidance system, said sheeting material comprising:
(a) a first layer of a substantially transparent polymer resin having a front surface and a rear surface, said rear surface having retroreflective elements to retroreflect light incident on said front surface;
(b) a patterned layer overlaying said rear surface of said first layer and adhered to be in contact with some of said retroreflective elements and essentially out of contact with others of said retroreflective elements, so as to define a pattern of cells, each cell including a number of retroreflective elements out of contact with said patterned layer;
(c) an adhesive layer applied to said patterned layer to adhere said sheeting material to an associated surface; and (d) a phosphorescent pigment contained within one or more said layers, whereby said sheeting can function as a marker for a visual guidance system by emitting visible phosphorescent luminescence after a source of illumination is removed, and by retroreflecting visible light incident thereon.

2. The sheeting of Claim 1, and further including a layer of hydrophobic silica disposed within said cells.

3. The sheeting of Claim 2, in which said patterned layer comprises a clear adhesive.

4. The sheeting or Claim 3, in which said phosphorescent pigment is contained in said patterned layer.

5. The sheeting of Claim 1, and further including an opaque layer to enhance the luminescence of said phosphorescent pigment.

6. The sheeting of Claim 5, wherein said opaque layer is white.

7. The sheeting of Claim 1, in which said phosphorescent pigment is contained in said first layer.

8. The sheeting of Claim 7, in which said film is flexible and said retroreflecting elements are cube corner elements formed by embossing.

9. The sheeting of Claim 1, in which said retroreflective elements constitute cube corner retroreflective elements formed by casting.

10. The sheeting of Claim 1, in which at least a portion of said retroreflecting elements are metalized and said adhesive layer is applied to portions of said metallized surfaces.

11. The sheeting of Claim 1, wherein said retroreflective elements comprise a matrix of microsphere beads.

12. In a cube corner retroreflective sheeting comprising a substantially transparent and flexible film having a plurality of cube corner retroreflective elements on the rear surface thereof and having one or more additional layers of backcoating or metallizing and adhesive applied thereto, the improvement consisting of a phosphorescent pigment contained in one or more of said layers so that said sheeting will glow in the dark for a limited time after an illuminating source is removed.

13. A photoluminescent retroreflective sheeting comprising:
a first layer of retroreflective film having a first side and a pattern of cube corner retroreflector elements formed on the reverse side to retroreflect light when illuminated by a light source;
a second layer of clear adhesive screen printed in a pattern and cured on said cube corner elements;
a third layer of film adhered to the printed pattern and otherwise spaced from said uncoated cube corner elements;
an adhesive layer formed on said film for attaching the sheet to a surface;
a release liner removably secured to the adhesive layer to prevent inadvertent contact of the adhesive layer with a surface; and a phosphorescent pigment contained in at least one of said first, second or third layers to cause the sheeting to glow in the dark, and coloration pigmentation contained within one or more layers disposed behind said layer containing said phosphorescent pigment.

14. The photoluminescent retroreflective sheeting as in claim 13, wherein said phosphorescent pigment is in said second layer of clear adhesive.

15. The photoluminescent retroreflective sheeting as in claim 13, wherein said phosphorescent pigment is in said first layer of retroreflective film.

16. The photoluminescent retroreflective sheeting as in claim 13, wherein the screen-printed pattern of adhesive creates air cells that are sealed by the pigmented film layer.

17. Photoluminescent retroreflective sheeting comprising:
a transparent film having cube corner retroreflectors embossed on the reverse side thereof for retroreflecting light incident on said film;
a layer of hydrophobic silica screen printed in a pattern of the cube corner elements;
a clear back coating containing phosphorescent pigment formed over the hydrophobic silica layer and the exposed cube corner elements to cause the sheeting to glow in the dark;
an adhesive secured to the back coating for attaching the sheet to a surface.

18. Photoluminescent retroreflective sheeting comprising:
a layer of transparent extruded film embossed on the rear surface with retroreflective cube corner elements that retroreflect light incident on said film;
a phosphorescent pigment contained in the extruded film so said layer will be photoluminescent and will glow in the dark;
hydrophobic silica screen-printed in a predetermined pattern on the extruded cube corner elements;
a white pigmented adhesive formed over the silica pattern and the exposed cube corner elements for attaching the sheet to a surface; and a release liner attached to said adhesive to prevent inadvertent contact of said adhesive with a surface.

19. Photoluminescent retroreflective sheeting comprising:
a first layer of transparent thermoplastic film embossed on the rear surface thereof with retroreflective cube corner elements for retroreflecting light;
a phosphorescent pigment included in the film to form a photoluminescent composition such that said first layer glows in the dark;
hydrophobic silica screen printed on the phosphorescent pigment in a predetermined pattern;
a white pigmented water based back coating formed over the hydrophobic silica pattern;

a layer of adhesive attached to the back coating for attaching the sheet to a surface; and a release liner attached to the layer of adhesive to prevent accidental contact of the adhesive with a surface.

20. A method of forming a photoluminescent retroreflective sheeting comprising the steps of:
embossing cube corner retroreflector elements on the reverse side of a thin flexible film to form a retroreflective layer that will produce retroreflective illumination upon receiving incident light;
screen printing a second layer of clear adhesive in a predetermined pattern on said layer of embossed cube corner elements;
curing said second layer;
laminating a third layer of film on the printed pattern;
applying an adhesive fourth layer to the third film layer for attaching the sheeting to a surface;
removably securing a release liner to the adhesive layer to prevent inadvertent contact of the adhesive layer with a surface; and including a phosphorescent pigment in at least one of said first, second or third layers to cause the sheeting to glow in the dark.

21. The method as in claim 20 further including the step of placing the phosphorescent pigment in the second layer of clear adhesive.

22. The method as in claim 20, further comprising the step of placing the phosphorescent pigment in the retroreflective film first layer.

23. The method as in claim 20, further including the step of placing the phosphorescent pigment in the third film layer laminated on the printed pattern.

24. The method as in claim 20, further including the step of creating air cells with the screen printed adhesive pattern that are sealed by the third film layer.

25. A method of forming a photoluminescent retroreflective sheeting comprising the steps of:
embossing cube corner retroreflectors in the reverse side of a transparent flexible film to form a retroreflective layer for retroreflecting incident light;
screen printing a layer of hydrophobic silica in predetermined pattern on the cube corners;
forming a clear water-based back coating containing phosphorescent pigment over the hydrophobic silica layer to cause the sheet to glow in the dark;
applying a pigmented adhesive to the back coating for attaching the sheet to a surface; and removably attaching a release liner to the pigmented adhesive to prevent inadvertent contact of the adhesive with a surface.

26. A method of forming a photoluminescent retroreflective sheeting comprising the steps of:
phosphorescent pigment containing film to form a photoluminescent film layer that glows in the dark;
embossing cube corner retroreflectors on the rear surface of a layer of film for the purpose of retroreflecting incident light;
screen printing hydrophobic silica in a pattern on the extruded film cube corners;
forming a pigmented adhesive over the silica pattern for attaching the sheet to a surface; and securing a release liner to the pigmented adhesive to prevent inadvertent contact of the adhesive with a surface.

27. A method of forming a photoluminescent retroreflective sheeting comprising the steps of:
embossing a layer of extruded transparent thermoplastic film including a phosphorescent pigment with cube corner retroreflector elements on the rear surface thereof for retroreflecting light, and which provides a photoluminescent film layer that glows in the dark;
screen printing a hydrophobic silica on the embossed cube corner retroreflectors in a predetermined pattern;
forming a white pigmented water-based back coating over the hydrophobic silica pattern;
applying a layer of adhesive to the back coating for attaching the sheet to a surface; and attaching a release liner to the layer of adhesive prevent accidental contact of the adhesive with a surface.