CA2844097A1 - Vacuum insulating glass unit with viscous edge seal - Google Patents

Abstract

Vacuum insulating glass (VIG) units, edge seals for VIG units and methods for forming the edge seals are provided. The VIG units include an edge seal that includes a viscous material, which serves to restrict the rate at which gas permeates into a vacuum space defined between the glass sheets of the VIG unit. The edge seals are configured to allow the glass sheets to move laterally relative to one another when the glass sheets experience differential thermal strain and further configured such that viscous shear occurs within at least a portion of the viscous material when there is relative lateral movement between the glass sheets.

Description

'VACUUM 'E.,;iSULATING GLASS WITH VISCOUS EDGE -SE:AL
CROSS REFERENCE TO RELATED APPLICATIONS
l0001 I The present awheation claims the benefit of .priority of the f011owing US.
.provisional application*: .serial ïo,61.1514,:334, filed on August 2, 2011, and entitled "Molybdenum. Polyimide 'Support Spacer for 'Vacuum Insulating Windowsr serial no. 61/521,493 filed on AuguSt 9, 2011, and entitled "Mesh.Support Spacer for Vacuum Insulating Windows;" serial. no. 611522,307, Merlon August 1.1, 201 I, and. entitled "Nlesh Support Spacer with .Removed. Filaments.for Vacuum Insulating Window,' serial no.
61545,174, filed on (,)clober9, 2011, and entitled :"Improvernents.to- Support Spacers for Vactium Insulated WindOWS" serial n ..6081,209, filed on DecetTiber 29,..20.1I, and _entitled "ImprOvementS to ViSconS Edge:Scarf:1)r VaetturnInsulated:Windows;t!' serial tin,.
61/587,746, filed on January 1..8õ:2012, and entitled "HydraulieSealing Elements for Viscous Sealed Vacuum Insulated W.indOwsr:seriat no...6.1/588,860, filed on January 20õ.2012, and entitled "Flements. for Viscous Sealed 'Vacuum 'Insulated Windows;" serial no.
61 /624,582.õ
filed on April 1.6, 2012, and entitled "VaCULIM Insulated Window uh Viscous'Edge:Seal.;"
serial no.. 611652,946, filed on Nlay 30,2012, and entitled "Vaeumn Insulating Windows with 'Viscous Edge .Sets. Part Ell." serial nO, 61/670,857, tiled on dy 12., 2012., and entitled "Polymer. Spacers. Formed as 'Sheets for Vacuum Insulated Glass;" the eluire-diselosures of which are incorporated herein. by rekrence.
BACKGROUND
100021 gasTermeation: Because it playsa central role in this invention the concept of gas permeation is presented here.
R1003I Without continual orperiodie pumping thmoõ the initial. lew pressure of any vacuum'contained in a vesse1 will inereaseas atmospheric gas permeates through the materials of which the vessel' is. madeõ'Ilie rate. of pressure increase wilidepend on the rate of permeation. 'therefore the service if of a .V2LCUUTI1 insulating glass (VIG) unit is not indefinite hut can be emended, provided there is. 11.13.4 failure-of the ixigc seal, by periodic pumping .dOwn through a permanently attached or temporarily attachable pump out port.
I00041 With regard .to permeation Roth (1994, p 6-7).States -(referent4..-acited: other publications);
Gases have the possibility to .flow through solids eVen. lithe openings.present are not large enough to permit a reettlar flow. The passage of a gas .into, through and out of a barrier having no holes.large enough to permit more than a small fraction of the gRE, to pass through any one hole is knowrias permeation. The steady state rate of flow in these conditions is the permeability coefficient or simply permeability.
This is usually expressed in Centimeters. Of gas at STR [standard tc.l.m.peratu re and pressure] floWing per second thmtigh a square eentimettt dcrosi5Section, per millimetres of wall thieknesaand torr of pressure drop. across the barrier ideal vacutanshould maintain forever the vacuum (pressure) reached at the moment of ìtsepatation from the pturips... My real chamber presents a rise in pttssure .01er being isolated .from the pumping: system. The pressure. rise is produced hy the gas which permeates from outside into the ehatriber.
[00051 Also in regard to permeation O'Hanion (2003, p 70) 5tato (references cited:
other publications.):
PermeatiOn is a three Step process. Gas .11.6,:t absorbs on the Outer wall ofa vacuum vessel, diffuses: through the bulk, and lastly desorhs from the interior wall.
Permeation through glass.. ceramic, and polyrneric Milterials is molecular.
Melectiles tin not.dissoeiate on absorptiom Hydrogen does. diti.seelate on metal surfaces and diffuses as atoms that recombine before; desorption on the. vaellUrn wall.
[00061 Ceramic glasses typically used for VIG Ullits have permeability .to atmospheric .gaSes in the range. of 10-} to 10'13 (.1-11'..nittki(crnec,toity.
l00071 Vacuum Insulatin ilass Units, Vacuum insulating glass :units are known in the art. For example,..see U.S. Pat. Nos. 5,664,3.95; 5,657,W;
5,1)1.536;=5,9(p.,652; 6,444,2(31 13,1.6,29.1,036; and 7,141,110 B.2 the disclosures of which are ail hereby incorporated herein by reference, [0008j Vacuum insulating glass (VIG.) units comprise..two substantially parallel spaced apart glass sheets with a VaCuum in hebseen ati1presSure le$s than 'atmospheric pressm.
Between (he glass .sheets are viwally nonintrusive space rs that Inaintain the vacuum space by resiStingtompresSive.atmospheric pressOre. Common to all VIG units is an edge seal that seals the edge gap between the glass theets and maintains the vacuum by presenting low permeability harrier.
j00091 Thermal heat tratIsfer via cotWeetion and conduction eannotriecur through vacuum. Consequently the energy andassociated.cost .savings that eanrestflt from the use of V 16 units in applications such as windows, doors, andskylights can be on the order of ten timesgreater than for inert ga. lled thermal panetinits, which have aninertgas.such as argott or krypton at atinospherie pressure between theirglaSs sheets.

[00101 There .4re serious unresolved performance and reliability problems that continue to hamper development.of commercially viable \FIG units, forestalling the significant energy Savings that will result should they eVer .replaec inert g..filled thermal pane: Chief ainong 6.011.6 edge:seal .failore and sudden brittle fracture of therefativelynon-ductileglass sheets.
Thesefailures arecaused by large st:ressegresulting from differential thermal expansion and contraction tor "differential thermal grain") of the thermally separated glass sheels:. The patent record reveals an ongoing intensive effort.to Solvethis problem by em.ploying.more flexible edge sea1 tlesigns. The effint is spurred by a quest to capitalize on market demand fOr more energy efficient buildings,. The demand is diiven by a pressing need to forestall the mounting dangers of global warming by reducing green housegas.ernissions.
[00111 Steven Cbtt, Secretary, U.õ$...Department fEnefrgy,stated at the Calteeh Commencement, iune .2., 2009:
There.is a growing realization that we. should be ;:tble .to build buildings That will decrease .energy-use by 80 pereent.with investments. that will payibr themselves in.
less than 15 yeam. Buildings consume 40 percent of the energy in the U.S., so that.
energy efficient buildings can d.ecrease, our carbon emissions by one third [00121 At the time of this writing, residential buildings account for 22 peivent of-US.
energy consuMptionõ.commereial 18:percent. Of the 22 percent reSidential.
energy consumption, 42 percent is a result ofresidential heating and cooling.
Buildings ue 72 percent of the nation's. electricity and 55 pereentof its natural gas.
Buildings are responsible for approximately 40 percent of CO-, emissions in the USõ and approzdinately teragratns (Tg or million tonnes NW)) CO2 equivalent (sore e IL:S. 'Department of 'Energy).
)013l The U.S. Omen Building Council has instituted an internationally recogniged green buildintteertification system known asteadership Energy and:finvironmental Oesign ort,F.ED certification that promotes energy savinas, water effie iency,.0O3.emissions reduction, and improved indoor environmental luality. LEED.standards.promote greater us,e amoral light and visibility to the ouldoors Y1G units nuke this possiblewithout being at MSS purposes with MED energy saving and C.02 eMi$8iOn reductiOn standards. VIG
units greatly reducesound. transmission,. wh ich improves the quality of living and.
working environments.
[00141 Because there is a vacuum between them, the glass 'seets ìn.a VIG unit are thermally isolated from one. another to a far greater degree than thOse in.
inert p$ units. As a result, the differential thermal .strain between the glass sheets.ola VIG.unit caused hy indoor and outdoor temperature differences in climates with large temperature extremes is far greater than for inert.gas units. In a V1G unit 'with a rigid edge seal that joins both sheets of glass theSedifferences in thermal strain iiicet Ø: the unit'S.edges.where they are Constrained by 'compatibility. The result can be very large values Of stressin the relatively non-ductile glaSs sheets.and within the edgeseal and its bond to the .Rlass.Shects.
R10151 The large stresses that call develop in thc. elass sheets of ti nnitwith. a rigid edge seal can become So high that one.or both ceramic glass.sheetS.thay fail .suddenly ìn brittle fracture. This problem is 'exacerbated by ceramic 2:1.Ass7s senSitivity to lost; t)fsttength from scratches and abraSions, which can precipitate 'breakage. If a VIG Unit is a floorto windowon the 94th floor of &building and fails sucidenly in brittle fracture:the consequenees could exceed -the.cost .of the unit's ivplacement .and include injury or loss..of life.
[00161 Although ceramic glass has a number of negativephysical properties that are disadvantages in VIG Construction, the lad: of matetials.with .its unique positive physital properties makes. itvery difficult to circumvent ceramic. glass as the preferred transparent material for V1G units. The negative physical characteristics are brittleness., low ductility', low tensile strength, and a high a modulus of elasticity.The positive characteristics. ate very high rigidity, resistance= to creep deformation under continuous loadsAardness, and very importantly ceramic. Window.glass such as .sod.a-lime glass has vely low gas permeability', These positive properties make ceramic glass the preferred material for VIG
units, wtin;,711 are subjectto C011tiflUOUS flexural loads from atmospheric pressure .and 'which .must maintain .service Vacuum pressures for decades.
[0.01 71 If ceramic glass. was:more:ductile and had greater tensile strength then many of the problems plaguing VW :development 'would be greatly mitigated. Given that at present there is nosuitahlealternatiye to ceramic glass; the only 'available avenue for progress in VIG
development is imprdved Wo.scal. design, NMAITIber Of United States Patent Application Publications disclOse more flexible:edge ei:11 designs, which are attempts to mitigate ..many :of the current problems with VIG pertbrinance, assemblyõreliability,.and 3afety.
1100181 III mot of the VIG unilstiescribed ìn the art the distancebetwee.n the glass sheets is necessarily very much smaller than the distance between the glass Sheets of inert:gas filled thermal 'pane units and usually less than 0.08 inch. DeSpite the fact that close spacing. of VIG unit glass sheets eXacerbates the problem of fICCOMMOdatiria, dit'ereatiaI
thermaistrain betWeen them, Helose spacing a VIG unit glass :sheets is desirable became spacers need to be .small in order to be -visually nonintrusive. Small spacers:conduct less thermal energy. Close spacing of VW: unit glass.sheets reduces the time required to pump down the vacuum, which reduces production costs. Spacers may be or include round disks, cylinders, micro sized particles, or even nanoparticies .that may or may .rtot be inibedded within the glaSs sheets [00191u contrast.to the. typical distantes between the. glass:A:Ms a VIG
Units, the distances between. the glass sheets: of inert gas units is chosen to minimize Ilea transmission fro1 . conducztion and convection. Tat optimal .spaeing is between 0:625 and 0.75 inch Bee:tw e the diStances between the tilass.panes Of inertgaS thermal pane windOws..are much gtvater than for VIG units, the stresses that develop in their edge seals are less than those 'kr Vhi units given the sane. lateral displacement between the glass sheets and similar sealing materials. Therefore the smaller differential thermal strains that develop hoOveen the glass sheets of inert gas units.as compared triVIC units can he accommodated bysimpiellexible elaStic seals that need not resiSt collapse under one atmosplicre.of prtSsate and that need not maintain a one atmosphere .pressure difference for decades.
100201 The rigid ceramic solder glass orglass frit edgeseals that: are currently used in.
VIG.tinits and that are known in theart present serious problems...Seals of this type are disclosed by U.S. Pat, Nos. 5,664,39.5 and 5,65707. The advantagesof ceramic solder glass edge seals are their very low gas permeability and strong bond to ceramic glass substrates.
Their &advantage is brittleness and tendency.th er.aek or fracture in climates with large.
temperature. extremes such as mem in 'North America. It takes only a very small invisibie crack or breach in a VIG edge seal to drastically .reduce a unit'sservice life and to make repair infeasible.
100211 In the proCess of foming rigid ceramic solder glasS edge Seals the ceramic. glass MUSt be heated aboVe.a temperature that will remove tempering anc.i inn-IA.0m unwanted stresses. within the glaSS.Shects, The long hcating and cOolin a times associated with this process increase manufacturing costs. The high assembly temperatures require the spacers to be of a.rnaterlai that can. v,ithstand those.temperatures. This limits the rartgeof suitable:spacer materials and excludes 'Materials with lowercoefficients of thermal conductivity Of higher creep resistance; US. Pat. Nos. 6,701,749; 6,558,494;
6,541 3;.
04-1,689; 6,63532.1. 6,47a9l l 6,365,242; and 6;336;984 disclose methods that reduce the assembly temperatures of VICir units and allow the glass .Sheets to retainsome hut. not all of their tempering.
(00221 Rigid edge seals can cause biliging out.of a VIG tiiit's.glass. sheets.
For .example, if it. is colder outdocAs the outer glass. sheetwill contratt causing both the inner and outer glass sheets to bulge inward toward the interior oldie building increasing the likelihood.

.of fracture. Bulgina noticeably distorts reflections creating an.
objectionable On aesthetic fun.
house environment.
100231 NippOn. Sheet Gass prodtices commercial VIG units NYi th ceramic solder as edge seals under the trade name Spada. U.S. Pat, NoS. 5,664,395, and 5,902;652 also deserilx,' such Vi Ali ts.'Service= information publiShed for these :inits. by Nippon Sheet G aSs reveal many of:the problems presented above,. The service informAion states in part (Nippon 2003) (referces Cited: other publication.) Precaution far USe. and. inalortainance . When wired glass typeis used. iïdiferent applientlim from. Conventional vindow, please eonnict is before use,. to avoid of thetrouble due 'to-them:id brea.kaae.
2. it paSto the film aild. paper On SPACIA... It niay brings it thOrtn61 breakage..Sligindislotation and occasional omissions irs,even if they are .foand, are îgih i ter nis of product performance.
3.SPACtA..is.required. to use in temperature condition dui its diferenee between and ouT is preferably less than 3.5'.0 4. 'Don't touch ort SPACIA with metallic or ceramic bard sharp. Deep scratches somctirnes lead to .i.tlass breakage.

5. Some deformation of refleetive 'image is unavoidable for process.
reastOns.
and .ibrthe occasional warpage of .giass in case of a biL4 temperature difbrenee between IN and OUT,. )1ThiCh is based on it% higher thermal [0:024j The problems associated with rigid edge seals can be reduced if a flexible:seal is ud.HoweVer, in comparison toi.stationary rigid seals, it is more difficult. to achieVeltrw permeability and leak rates for seals thin accommodate or tt'ansmit motion.
This difficulty exists to various reasons that include the following:
materials.generally have higher gas permeability than rigid materials, and it is difficult to form lasting reliable bonds or tight fits between flexible elastic materials and the more rigid ItiatarialS Cir configurations of vaeutan.VeSsels.. The VIG edge seals.disclosed by the United States Ihttent .Application 'Publications discussed below aretneant to be ntore. flexible and ductile than rigid. solder glass s.
[00251 Tie problems with rigid ceramìc. solder glass edge seats and rigid edge seals for VIG units discussed abo.ve are enumerated fly United States Patent Applieation Publications Nos.. US 200S/0166570 Al and US .2009/0155499 A . These publications disclose 'designs mitigate, but that clo not eliminate,. the above described problems by in trod.ueing metal as a bridging niatria i between the edges of the glass sheets. Metal has greater ductility and flexibility than ceramiesolder glasS. This allows' sortie niovernent of the edges of the. ceramic claSs sheets relativa to: Doe another under differential thertual strain.
Thistmilts in less stress an.d likelihood of fracture. Some of the metal seals that a.re diselose.dtv the:above publications are bent and folded into spring like fonts that thrther increase.their The.se publications. show.Sorric..' Of the nietal seals aS being entirely betWeen the glass:sheets:SO
that One of their dimensions is lted /-yy the stnall distance between the glass sheets. This requires tight .folds in the folded over metal .forms and pines limittitions on the .strains that can be accommodated Without t.Aceeding the elastie limit of the metals. Ciiven the number of eyeles of loading and unloading that would mem on a daily basis.year.aileryear.Oecattse..of tXpailSion and contraction of the glastsheets; the metal seals disclosed by the above publiegions would very likely experience 'strain .or work-hardening and become increasingly less ductile; possibly- to a poirit:where cracks or fisSures would. develop that would admit air into the vacuum at an tmacceptable rate, shortening the seiwiee life nfa VIG
unit to yeas opposed to decades. In regard to 'work-hardening of flexible metal joints that seal vacuums õIOusten (MS, p 785) states.(tefetence,s cited: other publications)!
For high - and ultrahigh - vaoutim equipinent, flexible metal. elements.ate used, which are welded or brazed to the flanges Such eleme.nts include hydraulically.
..tOrmed bellows (the longitudinal section is wavy) and diaphragm bellows (diaphragms, welded at the outside and inside perimeters), .Becõ:ause they are made of 'metal, every component of this type is. Subject to work,,hardening and thus wear, depending on the number of working:0,6es, [0:026j The: folded over forms diselosaby the above publications. arc only eiTeCtiveas springs in one direction, whereas differential thermal strain in the glass Sheets: of aVIG unit OCcurs irt two dimensions, [00271 United.States Patent Application Publication No. US 2009,10155499 Al :discloses that the contemplated metal .edge seals may be bonded .to the glass substrates by methods requiring lower temperatures than thoserquired for solder glass seals, The methods and rita.terials for bonding .the metal stripsto the glass. substrates as diselosed by Pub,'Nos. US
2008/016070 Al and S 2009/0.155499 Al are elaStie in nature: Therefore the bond and bond material are subject to all the forces within the .inetal strips theinseKes. Those forces will be a fUnction of the :modulus of elastiek of the metal and the..straitt.
GiVenseals made of .elastic materials or having elastic. bonds, any relative lateral displacement of the glass sheets.

will result in stresses that persist as long :as the displacement persists, Under load,, elastic materials are subject to failure from tensile rupture, shear rupture, stain hardening, and bond failure betWeen joined elastit: materials, Bond and material failureis a general problem with any primarily elastic: material or bond: 'USW. for sealing .the edges of VC
units.
100281 United States:Patent Application 1.)uhlietttion No. US 2.010101.78439 A
I
discloses a flexible edge seal rvacuum insulating glazing units. The preferred embodiment di seloSe$ a flexible edge seal eOh$isting Of a thin metal with convolutes...The...seal is...hOW11as being exterior to the space :between the glass sheets of a VIG unit, Thesurthee area of the scat as disclosed. iS ivy. much .greater than the surface area defined by the gap between the glass-sheets, .Two of the factors affecting rate of gas: penneation are the surface area and thicknesSof the material through Nvbieh as permeates. The greater the surface area and the thinner the material through which gas permeates the greater will be the. rate-of permeation.
In this regard the seal as disclosed by Pub. No, 'LIS 20101017$439 Al is less than, optimal..
The design of this. seal requires a space, and therefore steatearea, greater than the confines between the glass sheets will allow. The thin metal is bonded. to the glass.sheets and is therefore subject to both bond and elastic material failure moties, [00291 United .States Patent Application Publication No. US 2010/0034996 A
diseloks a flexible edge seal for Vacuum insulating glazing units yery similar to and v,,ith the .same shortcomings as that disclosed by Ptib, No, U.S. 20104178439 A:l.

SUMMARY OF TILE INVENTION
[00301 Unless otherwise quald, as .it relates to this invention glass herein means any material that has a glass:transition. temperature-and ineludes thetallit, organic, a.ad ceramic glaSsesõ the latter including Vpi __ indOW glass suCh:as soda-lime glasS.
Glass herein also means any Wassas described above that mayinelude other constituents in its composon web ets but not limited to nanoparticies or nanotubes, µv.hich nifty improve or augment the physical eharacteristieS oftheglaSs or respOnse Of the ilass.to __ iass herein alSO
includes glass that __ haVe actiVeorpagsiVe deviees imbedded wholly 173r ptirtially within it.
[00311 Glass. sheet .herein includes 'laminated gliis.S.,'SkiCh as for example, glass sheets bonded together by. a. pol.ymer...Glass sheet...hercin also in eludes arty :glass objeet.that preponderantly flat with .substantially even thicknesshutch mayalso hueraised contoured attas in region.S.that may futien to naintain4 space and separation between be otheiwise flat and even thickness regions of two: glass sheets. "-Though not .detailed herein, this invention contemplates that glass sheets 'with raised contours thay be .tised in some embodiments. Glass sheet herein also ineludesarty glass Object that is pr<Tonderantly flat with substantially' even thickness but which itiay also have recessed regions whose purpose may include containing a viscous Material. A glass sheet herein tnay have coatings applied.
100321 Vismius material herein means .any material that flows like a liquid when a fOrce is applied and includes both linear and nonlinear Viseous materials.. and Bingham plastics. A
viseoas material may include nanopartieles Matmay reduce permeabiiity. Not included as a viscous material herein is any glass as defined above that is at a .temperature below its glass transition temperature.
[0.033j Various embodiments of this invention relate. to VIG units that comprise two substantially parallel spaced apart glass sheets with a Ne.acuum space in between and Mat have .oncor rnorecclge seals that comprise a viscous material with low gas permeability. The viscous low gas permeability material brides atleasta portion of the gap between the Wass sheetsand surrounding the Vacuum spate so as to act as at least a partiatneal .for the vacuum.
Because the gap is..bridged by a viscous. material that undergoes-viscous shear ivith very low .shear stress., when th glass.Shects. move relative to onennother the stresses in die glascets resulting from those viscous..sbear stresses are insignificant and cannot.
contribute to fracture, of the glass sheets or noticeable bulging of the glasssbeets. Relative lateral movement ate glass sheets.oceurs..dafing times of changing terriperature difference between .indoots. and outdoors. Beea.use thehridging material is viscous,.when relative.lateral movement of the glass sheets CeaSCS.S0 too does the shear stress,. This isnot the ense:.for .edge.seals made entirely of elastic materials where. static relative displacement results in sustained stress in the glass sheets.
100341 Barriers to Constrain the viscouS Material and methdds.td place it intotisSembly cid not require heating the.glaSs.Sheets:aboVe a temperature that would alkettempering of the glass sheets, orcoatinits on the giass sheets, or f!,k4ss lamination. Because high temperatures are not tleededfor.edge seal assembly, high temperature resistant .spacers.
are not required, allowing selection of spacer composition from a. broad, raritte of materials that 'may have lower thermal conductivity and lower hardness that is 'less likely to scratch ceramic glaSS.
[00351 Given the nature of viScons fluid flow and the no slip condition, it is not possible tbr the viscotis material to fail as a seal because of tensile .rupture, shear rupture, fracture, low temperature brittle fraettire, fatigue, material breakdown, delaminatiothõ
separation, splitting, bond failure; adhesi*!. failure, or strain hardening as might occur with material's that art primarily elastic in. nature. As a result. VICI units that employ a viscous edge .seal as disclosed herein win :tail with .farless fr.equeneyand with iess:potenti al damage and risk than VIC units that:employ edge seals made entirely of materials that are. primarily elastic, [00361 A viscous material used in a viscous edge seal may hed.egassed or otagassed: in a vacuum autociave or by some other method. As examples, without limitation, methods to degas s cu. outgaSs a viscous material may include 'creating a vacuum intontact µvith it, heating, stirring, sonication, and creating thin cascading tiow. Without limitation any method.
.to degass oroutgass a. viscous material may include any combination of the forgoing methods.
100371 The interior i)f a vacuum autoclave Or. ether veSsel that contains a &gassed or outgassed viscous. material .may be in communication through hermetically sealed ..connectidts such as.. tubingOr fittingstO a press or can extruder, !knny Orserew.extroder, rotary extruder, pump, or directlyto:a cavity in a \AG unit into Which the ViSCOUS .material is.
to flow. Alternatively a press:or other mechanism to CA= viscotts flow may be an integral assembly within a vacuum autoclave. After the glass sheets. ola VG unit have been brought together, sandwiching all orsome of the. spaders in between, a eavity.conligured to contain a viscous tnaterial.as part of a .viscous edge seal may be evacuated to a pressure less than atmospheric pressure through a pump out hole or port or through multiple pump out 'holes or ports that ma2,,f pass into the c.avity and airmail any intervening .material, As examples, and without limitation, intervehitta materials tha).¨include any or all of the following: a alassshect of the VIG unit; any sinters, elements., or materials that May be a:part of an edge seak and or any materials ..forming part of a cavity that will contain viscous material that may not necessarily include a Ow sheet or edge seal component.
DegassedorOUtga,Sett.ViSPOPS.
material may .then be pressured into the evacuated cavity through a.filler hole or port into the cavity or through multiple filler holes.or ports that maypasSinto the cavity and through any.
intervening material. As examples, and without limitatiOn, interveningtneterials rutty include atty or all of the following: a glass Sheet of the 'VICi unit; arty spacers,elements or materials th.at may be a part of an edge .seal; and or .any materials tOrming part of a cavity that will contain viscous friaWial tha.tmay tot necessarily include .a glass.sheet. or edge seal component. The cavitymay ortna.y not remain under continual vacuum pumping to maintain a low pressurelis Me viscous .010.taifil is pressured into it. fielbre or after the eaVityis fil.led or partially filled with v.iscous material a vacuum pump or pumps. and their connections nlay be released :from the pump out port or ports and the port or port's may he scaled. Likewise the:
connections arid fittings .to a press, other device,. or container diatomite.]
floW of the viScouS
material may be released and the filler port or ports may hesealed.
1.00381 To preSsure. a viscous material into a cavity means to create total.
'pressure or total head in that viscous material so that the viscous. material flows:into the cavity. That total pressureor total head may be created hy any method. Those .methods may include, .without limitation, a press. or pressextruder.õ a pump, a screw .or screw extruder, a rotary extruder, a extrader,or taiSing:the viScous Material higher than or to the height in the cavity to be occupied by viscous material.
f1o391 non-limitingexamptes a..cavity may be any container, reservoir, or physically bounded region that is part oft VI unit and that istonfigured to contain a viscous material.
Or .fluid. A cavity configured to Contain a vistotts:materia.1. Where the:
Vistous material may be part. of anedge seal for a VIG unit, .may be entirely 'between the glass:
sheets of a VW unit, it may be entirely outside or not between theglass sheets orit may be partially in 'between and partially outside .the glass.shects, A ity may cornprisernatiple sub-cavities that are ii.
open communication such that a viscous material entering any one of multiple sub-cavities may:flow to one or more oldie other sub-cavities. The sub-cavities from which .the cavity coo figured tocontain aviscous material is COMprised may be, for example, connected in.
series and/Orin :parallel and/Or inay le cOntainedwithin other sob-cavities.
Viscous material may flow between connected subreavities or from one seb-cavity to another while a VIG unit is in service. A cavity m.ay be open to the atmosphere such that a viscous material contained by it maybe open to the atmosphere and therefore have an open free. surface, in the saute 'sense that a glass. Containing 'water has .an open free stirface, A cavity tna.yeomprisea material that .floatS on top of or that is otherwisein contact with a free surface ofa.Viscous material contained .by the cavity such that as the volume of the .viscous material changes ith thermal expansion and, contraction, and rises and falls .vithin the cavity, the material on top also rises and falls, [ON4 ! if a cavityas defined .above. Wit-tains 8 ASOods.materiat.and. any portion of that viscous material is included in an edge seal then all of the vispous material contained. by that cavity isoonsidered to be a part of the .edge seal.
100411 A cavity containing a viseous.material as part. or an edge. seal may or may nOt have its= entire volume occupied by that viscOuS material.
NO42j Thovolume t'irany cavity containing a viscous material truly be variable and may change with .thermalexpansion and contraction of the materials ttf a VIC
unit including the viseousmaterial. changing volume. ofa cavitycontaining a viscous material, though relatedito material. expanSionand Contraction, ntay be the direct result of,..without exuding of viscous materials between edge seal elements or components; and or movement, :expansion and .contraction, or inflation .and contraction of rigid, -flexibleor elastic membranes or components.
[00431 A cavity configured to contain a viscous mtnerial may or may not be evacuated to a pressureless than atmospheric pressure betbre.viscous material is .pressured into it. A
cavity configured to cOntain a viscous material May be evacuated to pressure lesS titan atmospheric pressure and put through an .outgassing bake-out before viscous material is pressured into it, 100441 As part of a process that includes pressuring viscous material into a cavity configured to contain that viscous material, the main cavity bOtWeell the glass sheets of A VtG
unit .fhat contains spacers and is meant to be viewed through may beevacuated to a pressure less. than atmospheric betbre, during, or after *ikons material is pressured intoits cavity.
Lvacuating or pumping down the .Main cavity to a pressure less than atmospheric pressure before or while pressuring 'viscous material into its cavity may cause the tilass sheets.to.resist separation as-viscous material is pressured into its cavity.
[0045l A ritwilote: or port in a glass sheet through i..vitich gas, air, and viscous .material may flow may- h&c. t 'iitg.Otrings .made Of Materials other thanglasS cemented into it to providostructural strength to. the .glass around the hole or port. Cement or adhesive:may penetrate into agrotmd surface around a hole or port in a glass sheet forming a Strong bond with a ring, which may he ametal, polymer, or composite.. A ring may have features that allow quick hOokUp or installation of tubing. or other fittings. for, but not limited to., pumping., .evacuating, pre.ssuring, and sealing.

[00;461 Polymers, because of their low thermal wild high,- suitable materials from whichspacers may be compris4 of which spacers may-consist or of which spacers rutty consist eSsentially of. The use of polyiners ísfilmic possible by the relatively LOVte assembly temperaturesaiforded by ViSeous.edge Becautio=the spacers may be disposed in the main vacuum space of a VIC unit in a potton of a VICi unit that is meant to be viewed through, the spacers may be eompowd of a polymerthat is transparent to. visible tight, GOO d candidate. polymers includeõ.but are not limited to,=polyitnideõ
polyarnide, pdlyetberimide, polyearbonate, and polybenzimidazole. Polymers used fir spacers-may have fillers that .may include but are not limited to glass fibers, Carbon fibers, or molybdenum disulfide, .Molybdenum disulfide may reduce frictional forces while the carbon and glass fibers may i wart enhanced.tensileõ.compressive, and shearstmogth while alSo reducing, creepõ Other fillers: netay Melt:1de carbOn blaek cir other ;Itdditives that imprOve, polymer resistance to oxidation cm that reduce degradation caused by ultraviolet light or other light spectrums.
00471 Polymer .spacpm tilay have molybdenum disulfide embedded in or deposited on a fare that will contact one of the glass sheets to provide low friction.
[OA Any USeof the term polymer herein means a polymer that may include a filler or fillers. Any aseof the term polymer herein means a polymer that may include a -material or materials embedded in a surface or face of the polynter.
[0049j Polymers. may he easily formed into various=shapes for spacers .thatmay he.of particular advantage inlimiting heat conduction while prov idhlg.resistanee to overturning moments caused by fictional forces between the glass sheets: of a VIC unit. la basic embodiments., the: spacers comprise. two oppositely facing end faces connected. by a spacer body: AS =an.extiniple, a cylindrical spacer may doinprise two spacer Segnients. Nvhere.in one .olthe two segments has a larger diameter than the ottterof the two spacer segments. Ttw larger diametersegment may form a stabilizing foot at one end of the spacer .body. The .smaller diameter segment may .makeup all or most of the remainder of the spacer body. The end face of the larger diameter segment may be adhered to one of tho glass:
Sheets. of a V 16 Mlit vhíie the end face of the:.smaller diameter segment may be in contact.
with the other.g.lass sheet NVithout being adhered. to h. The smallerdiameter segment reduces.ifiethconduction compared to that of the larger charneter.seament while the lamer diameter end face anchored to one of dteglass sheets resists overturning moments created by friction caused by CCM tact betWeen the end face of the sMaller diameter segment with the other glass:sheet The tOrttoing configuration allows spacer thickness to be increased without increasing spacer diameter or cross sectional area.of the entire spacer in order to maintain spacer stability. Incrt,sasing .spaoe,r.
thickness decreases heat conduction. Having to inc se spacer cross sectional area. to.
maintahiStability *hen increasing spacer thickneSs would negate reduction in heat conduction provided by thicker:spacers., inereasing Spacer thickness and consequently increasing eõapdista.nce between glass sheets of V10 :it etavinerease.the soviee life of a Vici unit .hy increasing the volume of thevacuurni betWeini the: glass sheets, Given no change -in permeation rate as vacutint volume increasoS the pressure riSe over time caused by permeation will 'be slower thelarger the vacuum volume.
100501 When a spacer is. said to .he i.ctuttact with a glass.sheei it means that the Spacer may contact the glass sheet:directly .or thatit inay coact niliaerial that. is in between the glass .sheet and spacer. As examples, and without linthation, intermediate materials that may be in between a spacer and a filass Sheet may include coatings, polymers,:laates, powders, lubricants., adhesives, contact sheets, and active or pagsive devices, 100511 Instead of forming individual unconnected polymer 4)acers that must then be manipulated 01.5_4(Mle individual basis as part cif a process to place them on a glass Sheet Oa unit, eompre.ssion and injection molding methods available for forming and producing polymer parts can automatically create integral polymer interconnections between polymer VIG supPort spacers that may eliminate the time that might otherWisebe rapaired to manipulate and place a larg.e number of individual support spacers on a glass sheet.
ittercannec ted spacers allow simultaneous handling, manipulation, and .placing of spacers en masse as a set of pre-arrayed spacers.
10.0521 Pre-arrayed spacersarespacets that are thrmcd in a process or multiple proeesses that produce multiple spatzit with interconnectiOns between them that hokl and maintain thoSelipaeers thesathe array as they will have'when first installed betWeen the idass sheets of a VIC} unit...An array herein means a spatial relationship that includes both .geornetry and. distance. To say that first and a seCond array .of spacers is the same means.
that the first array can he superimpoSed on the second such that all the spaeersof the first and second. array µvill coinc. The: geometry.olan array need not he reetangular or square and be of infinite. variety. The.mometry and distanees hetWeen.SpacerS in an array mhy vary and need not be regular .or repeating.
[00531 Polymer pre-armyed spacers are spacers that are pre-arrayed where the spacers and their interconnections .comprise polymers, [0:0541 For example, it some embodiments interconnected spacer arrays comprising, for example, at least 10, at least .1000, at least 1000 and at least 10,000 spacers may be employed.

At some point in a process of a.s.f4mbly of interconnected spacers on a gas fibeet of a Vick unit some or all interconnections may bet-moved, In some instances a jig may hold an initially interconnected aiTay of spacers until the jig. sssheet are brought together,.
pmsing the spacers to the face attic as sheet where they may he adhered using.
a low outgassing adhesive that may he specified aceordingto AST M E59.5 [0:0551 To remove winterconnectionniCkUrigtO create a physical discontinuity betweer spacers where. material continuity had existed. This may include, btit ì not limited to, removing an ..entire interconnection, breaking an interconnection but otherwise leaving the connecting material .attached to .at. least orie.spacerõ or removing a pOrtion of an.
interconnection such that portions of the interconnection are still connected to one or more spacers.
[00561 Polymer'spacers may be ibrmed.Or Created soas to be interconnected to each other us part of a forming process or multiple forming processes.. Example 'forming processes, Nkithoutviimitation, may include injection and coMpressiOn molding techniqueS.
Interconnections may:comprise he polymer itself .solhat thous.ands of spacers may he manimdated ,simnitaneously.by hand and ort.)y initomation until some or all of interconnections are removed either before or after or both betbre and after spacers .are placed on a glasS Sheet. The interoMmectiOnS may be in the forinOlatvntintious unbroken sheet with no holes' or discontinuities or there may be holes or discontinuities in the sheet of any si,ze,:shape, and or relationship so on as the spacers can be manipulated as a whole and their array essentially .maintained until the interconnections are removed.
100571 To place. a spacer or spacers ort a.giass sheet means either to place them directly in contact with ttre glass sheet Or in contact .with an intermediate material that may be in 13ONVeirt the spacers and the glaSs Sheet. Asinen-limiting eicamplesõ
intermediate materials may include coatings,. laminations lymers, powdem, lubricants, :adhesives, contact sheet, and active or passive devices. To adhere something to a glass sheet such as, hut without limitation, a spacer, interconnection, or polymer sheet means that it may be adhered directly to the glass sheet otto an intermediate material that. is i.nbetween it and the glass sheet. Any component ofa VIC unit that is adhered to a glass 'sheet has thesame definition of adhered. as above.
[00581 .A polymer sheet herein means any interconnection or interconnections betwwn an array of VIG spacers:that comprise a polymer or polymers and may have disci:infirmities lit the fOrretof holes of any size,sa l ape! and or conkuration and may have varyitut thiekne,ss.
and or perforations, and esped ally reduced .thiekness or indents or .perforations where the sheet transitions to or becomes. a spacer. A polymer sheet herein may be a mesh with.
filaments of any size, shape, and thickness. A single filament may have variable size, shape, and thickness.
[00:591 As an example, a thin polymer. sheet -that is:timed or created that integrally interconnects .VRil polymer spacers may corivrise spacers imbedded therein as an array of thickerregions of the thin polymer sheet. The polymer spacers, while. still interconnected to one:another by the .thin polymer sheet formed at the saine time anti of the skill10 polymer as the spacers., may be adhered to one Oftho.glass.shetts ofa VW unit, after which .the thin polymer sheet May be removed. Reinoval roa be hyõ hut not limited .to, pulling, ripping,.
punching, or shearing, The thin polymer sheet may be removed around the circumference or periphery,..or.c.lese to the circumferenceor periphery, of each polymer spacer:leaving an array of individual and no longer intereOnnected. pOlynter spacers: adhereato the glasaSheet. A thin polymer sheet prising polymer spacers may he thinner and or have formed perforations at its interconnections or transitions to the imbedded or integral polymer spacers so. as to reduce the three neces,sary to retnovethe polymer sheet from the polymer spacers:
100601 in the preceding example polymer spacers are produced with polymer interconnections as part ofa thrilling process and thoseinterconnections .hold the spacers. in the sable array they will. have. When first installed between the glass sects Dia VI(. unit.
Theretbre in this example the spacers are polymer pre-arrayed. spacers. This allows the spacers to be manipulated by hand or by automation en masse until it 378y.t)e.convenient to remove .some or all .of the interconnections.
100611 in some instances it may be. convenient to remove interconnections after spacers have been placed on a glaSS sheetas described in theexample above and in still other cases it may be convenient to temOVe interconnections.befOre theyare placed on t glass sheet as in the ease of a Jig as described .in the example. below, In some cases at least s0.111e interconnections may be removed beforespacers. are placel op a glass sheet with still others being removed .after the:spacers are placedon the glass sheet, [0.0621 An array of interconnected spacers may be ..formed. The interconnections may hold and maintain ementially the. array that the spacers will have. when -first as.sembled ìri between the glass sheets .0:fa:LIG unit, which. would make de spacers pre-arrayed spacers, An interconnected array of spacers T.118y.be placed in Of .011 a jig that may hold and maintain SC r array independentof the existence of the interconnections created in theforining process. Like.wise a jigniay. hold an interconnected array of SpacerS.StiCh that if sortie or all of the interconnectiOns are removed.:Some or all of the spacers .may lose their placement in the array, An example here a jilt may hold and maintain a spacer array independent of the interconnections is. a plate. µwith an array of holes that mirror an array of spacers.
littereormected spaCers. may be placed on the plate such that the Spacersare held within the holes..lf all the intetronnettiOnsare removed, the spacer array Will !vital ntained by all the spacers being held by the holes in the jig, [90631 Spacers may be held with some resistance in or by a.jig whether or not the spacers are heId in holes as j.h.Stdescribed or held in proper relationship by a different method. Other methods of holding the spaeers.may include fatly substantes or static electricity; Spaeers .ay he heath a. jig not directly but by connectinns between'a polyther sheet and a jig, 'Resistancoand ffsity=may he treated byebut not limited:to, upress fit in hoes or other mechanical: methods or:by a light themical hond,.tacicor electrostatic charge.
At this point in the process, vh1e spacers ate still held by a:jig, intercennections may be removed by mechanical methods that may include, but are not limited to, ripping, tearing, shearing, punching, cutting, slicing, .Or ïndingAiternatíveiv interrowctions between spneen may be removed by method's that are:not mechanical and that may include, but are not limited to, melting, .chemical dissolving, or vaporization. The forgoing methods of interconnection removal may also be utilized if an interconnected amay .of spacers is first placed on a:glaSs Sheet of a V ki tinit vith or without the use of a jig. .Any method of interconnection removal may be used alone or in combination with any number of other methods. either simultaneously or in Series or in, any order or .(.)yerlap of application.
100641 Once interconnections have. been removed, the jig, stìIl holding the spacers in their original array, may place the spacers on A glass sheet by pressing the spacers to the glass sheet of a VIG unit. The spat ers.may protrude beyond the surface of the jig and the laces of thec*.Powd sPacers. may be charged with a low .outgassingadheSive so that when they are pressed to the glass sheet they adhere. After the jig has pressed the spacers to a glass sheet it may be paned away triviii the glass Sheet and the iresistance to Annoval of the spacers: from the jig is overcome and the.spacers. part from the jig and remain affixed to the 1ass.sheet [0.065.1 There :may be instance's where it may be advantages not to remove all imerconneetions between spacers while spacers are in or on a jig so that at least Smile of the interconnections may be removed while the spacers. are still in or on a jig..
A jig holding 'spacers may thereforepress spacers to a glass sheet with some or all of the spacer interconnections remaining. Remaining interconneetiOns may or May not be removed once.
spacers have .been placed on a glasssheet using a jig In some instances interconnections may not be removed while spacers are in or ona jig i:aid some or none of the interconnections may he removed once spacers have been placed on a glass sheet.
100661 A polymer sheet that interconnects polymerspacers may connect:or transition to 'spacerS at any pOint along the :axis ofa Spacer :as defined by a line COTIStracted vertical and at right anglesto the faces df the polyrnersheet.
[0.1-1671 Instead eljust a Jig being -used, a jig, die, and punch set may be used that twitches spacers free from a pol.ymer sheet, in other wOrtiS temov.es the interconnectiOnS, before, during., rafter placement On a glass Sheet. Placement of SpaCers. on a glasS sheet :may be initiated. by the stroke of a punch that simulttmeously breaks spacers free from a polymer sheet and presses spaeers to a glass sheet, R/0681 In all of thOltletlinds and processes described thus thrõ.intermediate materials rnny be used instead. an glass Sheet. One example is to use a punch and die to :separate.
spacers from .a. polymer .sheet, in other words .remove the interconnections, and to adhere the vacers to &Sheet of an intermediate material that bolds. their array until the ibtermediate material is .positioned over a. giass sheet and the spacers attached to it .are placed. on the glass .Sheet where they may be -adherett An intermediate material may be flexible:so as to more easily conform to any wave present on a glass sheet. A series:of intermediate materials May be used in a strieS :of prc.icesseS that transfers spacers: from one :intermediate material to another befbre 'spacers are placed on a elass sheet of a V.10 unit. In .some instances an intermediate material may not be removed from an array of spac.i.tts and may itself be adhered to a I.:class sheet while still holding spacers, ia these cases the intermediate material may remain between the :assembled giasS sheets of a VIG unit and become a permanent component.
[00691 Spacer's May be *Ceti on a glaassbeet by simultaneously placing the equivalent of an entire simultaneously produced array of spacers on a glass sheet or by simultaneously or sticcessiyely piaci ng sections of simultan.edusly produced spacer arrays on ii glass sheet o-r by simultaneously or suCcessively placing the equivalent of multiple simultaneously produced spacer arrays including fractions thereof on a glass'sbeet Spacers may he placedon a glass :sheet by being 'pressed.. to a glaSs sheet by a roller thatpasseS Over a spacer array:or .anuys and or fractions thereof, [00701 A .simultaneously produced array of interconnected spacers may be smaller than a class sheet, th these cases multiple arrays of interconnected:Spacers may be used...in a:
process of placing spacerson a .glass sheet: A simultancouSly produced :array-of I

interconnected spacers may he CII.t or rednced to any size to accOmmodfne any size glass.
sheet 100711 In some embodiments the polymer interconnections of a polymer sheet tnay com.prise filaments amaig between spacers: th sow embodiments it may be adVantages not:
to remove these filaments or to remove only some of the filaments and to include ail of them or those remaining in between the glass sheets ofa fully assembled VIC unit, 1.00721 In some embodiments .the interconnecting, polymer sheet may be clear or translucent, with or µvithout a color tint, and continuous ornearly so it may be advantages in thck caSes tO adhere or place with no adherenee:or partial adherenee-the entire polymer sheet \vith integral spacers MI aglass sheet without removal of any of the interconnections or with removal of only some ofthe interconnections.
[00731 Within all of the examples.or contemplated eillbodimen4> of polymer sheets arid polymer spacers and methods and processes for assem.bly and. placement of spacers in VIG
units, polymer 'spacers and or polymer sheets may be adhered, partially adhered, or not adhered. to &glass Sheet.
00741 Active:or passive devicesi coatings,. and chemicals may be attached to a polymer sheet or embedded in it and may include but are not limited to solar cells for the generation of electricity, chemicals and circuitry to produce and. transmit ctirrent induced by Solar radiation, photoehromie material or Chemicals, photochromic material or chemicals that react to electrical eurrent, photochromie material.or chemicals that selectively transmit, absorb, or reflect different wave lengths of 'electromagnetic radiation, and low emissivity or reflective coatings.
[00751 In all of the processes and arrangements described above for placing spacers on=
a glass sheet the 14.1.aSS she Elivi spacers can be in any Orientation, FOre,xample, and without limitation, instead of a sheet of polymer.spacera.heing positioned over a glass.sheet as part .of the plaCeMent process, a glass sheet may be positioned over the spacers and the glass sheet lowered to the spacers Or the spacers raised to the glasS.sheet or the glass sheet lowered while the spacers.are raised, 1100761 Alubset of polymerspaccrs interconnccõted by a polytner..sheet.
May...mean all of the interconnected spacers:or twoor more spacers up to the total number of interconnected 'spacers,.
(00771 A: spacer may migrate .from its initial position after havingbeen first placed on a elass sheet. Miaration may bethe result offOreeshetween the spacer and glass=
sheets or between intermediate materials in. between the spacer and glass sheets,. This may he more likely to happen if a vacer is not adhered to either glass sheer. or is part of a polymer s.heet that floats between the glass. sheets. The array that .spacers may..have when initially pleeed.on a glass sheet may change over tithe. Without limitation thiS 'May be cauSed hy a polymer sheet shrinicitigOver time or changing dimenaionS Caused by a bake-out procedure.
100781 Spacers.aud polymer sheets-may heontgassed beforeor.after being pined on a glass sheet of a V1Gtait. Without limitation, the outgassine tnay he done in a vacuum autoclave..=
[0079-1 Some illustrative aspects and embodiments o.f the invention are summarized below.
[00801 One ttspect of the invention provides a vacuum insulating glass.nnit C
1,hnprisink;::
a first glass .she t .and scond glass sheet with a v4cuttm space.in between, At: a pressure less than atmospheric pressurq at least one spacer in between the firSt and sec.oraglass.sheets configured to contribute to the separation of the first and second glass .sheets. and th.e maintenanceof the vaeUtlin space; and .kin. edge seal. The. Wgie seal ccnrises aViscous material,: wherein the viscous nlatria l restricts the rate at which:gas .permeates into the VaCIIUM space; the edge seal being configured to allow the first and second gla.c sheets to move laterally =relative to one. another when the first and second glass sheets experience differential thermal strainand timber configured such that viscous shear occirs within at leasta portion of the viScotis material when there is relative 'lateral movement 'between the first and second ghissi.sheets; and at least one barrier whose eontiguration constrains the viscous material. In some embodiments of this aspect of the invention, the viscous material is a Newtonian fluid, such as pOlyiSobu.tene.
l0=0811 The barrier in the. Vacuum insulating glass unit may he a viscous barrier in 'contact with the .viSeous material. In .so.the embodiments, at leastoneof the first and second glass sheets make,up part ofthe 'barter, .while iri otherembodiments, the barrier does not.
include either of 'the firstand thesecond glass. sheets.
[00821 In one embodiment, the VaChant insulating glass unit includes a .viscou.s material 'disposed in between. the first .and second glass sheets andthe barrier coniprises.afirst pair of strip spacers comprising a first ttip spacer an4 a second strip .spacer divosc.'d betWeen the first. and second glass. sheets on the vacuum spec side o.rthe viscous materialewherein the first strip spacer is affixed to the first glass sheet ail d the second strip spacer is affixed to the second alass.shect, and further whereinthe first and second strip spaCers. are in contact and able to movc. laterally with. respect to one another. The barrier further comprises a second pair of strip Spacers comprisinwathird strip spacer and a. fourth strip spacer disposed between the first and second glass shee,ts òtì the..side of the viseops. material opposite the vacuurn. space.
side,. wherein the third strip spacer is affixed to the .first glass sheet and the fourth strip spacer is affixed to the secOnd glass sheet, and further vherein the third and fourth strip. spacers are it .-tontact and able to move iaterallywith respect. to one::another. This barrier also comprises.
aNiscous harrier disposed in between the first pair of strip spacers and the viscous material and in between thc second pair of strip spacers-and the viscous matertaLExamples of vacuum instilatina .glass units in aceordance With this embodiment are depicted in FIGS, and are described iri. greater detail in be Detailed Description. section:, below.
[00831 In one variation of this einhodiment of the invention., tint and third strip spacers .are joined bya stripof material extending in between the first Enact third.
strip spacers and in.
'between theft01 glass: sheet and the viscous material, and further Wherein the second and.
fourth strip SpaeerS areloined by a strip alum-alai extending in between the third and fourth strip spacers and in between the second glass sheet and the viscous material, 1:00841 in another embodiment, the first and secondglass sheets each WS at outer :surface opposite. the vacuum space and an inner surthee facing thevacuum space and the edge seal includes an end cap having a first.extension portion that extends over the outer surface of the first glass sheet and a second extension portion that extol&
over the outer surface of the seCond glass sheet,. wherein the visCons material is disposed in between the outer suifaceof the -first glass sheet and the first extension and in between the outer surfaCe of .the seCOnd glass..sheet and the second extension. In this embodiment, the barrier includes a first strip spacer disposed ìri between the outer surface of the first. glass sheet arid the first extension on one Side of the .viscous material; a second strip spacer dispOsed in between the outer surface of the firstglaSS sheet and the first extension on the other side. of the Viscous material; a third strip. Spacer dispoSed iri hen theouter .surfitee of the Second glass.:Sheet and the seoond extension ()atom: side of theNiScous .materia4 a fourth strip-spacer disposed in betWeen the outer stirfaceolthe seecind ala.ss sheet .arid the second extension on the other :side of the viscous _material; and a viscous barrier disposed in between the first strip spacer and .the viscous material, in between the second strip spacer and the 'viscous material, .in between the third strip. spaeorand the viscous material, and lit between the fourth .strip spacer and the viscous .material. Ari. exampleofa vacuum insulating glass unit. in accordance with this embodiment is depleted.. in Fl.(ri fLand isdeseribed in greater detail in the .Detailed Description section, below:
I00851 in another embodiment, the edge seal includes an end cap that tbrins an enclosure around the peripheral edges of the first arid 'second glass tiheets, wherein the viscous. material fills the enclosure; and an elastic membrane that is affixed to and spans die gap separating:the perip.heral edges of the first and said glass sheets, wherein the elastic membrane is. configured t onStrain the vischuS material, .Art ex:ample:of a vacuum insulating glass unit in ace:Mance With this embodimentis depicted FIG. 9, and is described in greater detail in the Detailed Description section,. helf)w, [00861 In another embo-dinrent, the first and second glass sheets.each has an outer surface facing opphsite theYactinin space:and an inner sure facing the *acuarrt spacv.aind the gap separating: the first and second glass sheets tapers inward from the peripheral edge region attic first and second. glass Sheets. tn this .emhodiment, the edge..seal. include*. 'an end, cap thatfornis an enclosure around the peripheral edges fthe first and second glass sheets aM the Yisoustnaterial fins tendosure and:. extends into the taperedgap .separating the first and second glass sheets up to a point at WhiCh the:Surface.tenSion at its leading edge prevents it from creeping further into the. gap. An example of a vacuum insulating glass unit in.accordanceWith this embodiment is depicted in FIG. 10õ and is described in greater .detail in the Detailed 'Description section, below.
[00871 Anther aspect of the invention provides edge seals for VACUUM hisniating glass units.. in one embodiment of this aspect of the invention, the edge seal .eonprises. a first gl an.
sheet and. a second glass sheet -s.vith a. vaeuitin space in betweertat apreSsure less than.
atmospheric pressure. The edge seal in this embodiment comprises...a viscous material., wherein the viscous .material restricts the rate at which gas permeates into the vacuum; the edge seal being configured 'to allow the first and second glass sheets to .move laterally relative to one another when the fast and second glass.sheets experience differential thermal strain and further configured such that viscous. shear occurs. within at least:a:portion of the. viscous material v h al there is relatiVe lateral innvement between the first and second .glass slice*
and at least one harrier whose:configuration constrains .the viscous -material, 190881 Another a,speet of the invention provides methods for 'brining an. edge seal for a vacuum insulating glass unit comprising a first glass sheet arid a second glass sheet and at ieagt011e spacer in between the first.and .second glass sheets' configured to contribute .to the Spparation pi' the firstand second glass sheets. in one embodiment the method comprises sealing the edgeof the vacuum insultding-Oass unit with an edge seal which, togetherwith the first and st.:,=cond glass sheets, defines a vacuum space in between the first andseeond glass sheets; evacuating the vacuum space through a pump out port to a pressure less th.an atmOspheric pressure; and sealing'the pump out poll. The edge seal in this embodiment 'being configured to allow relative lateral movement between the first and ,second glass sheetS -when the firta and second glass sheets :experience differential thermal strain and comprising: a V SCOW :material, wherein the viscous material restricts the rate at which gas permeates into the v&o Sp4et.wen it pressatc less than annospheric preSsure and further ,,sdierein there is viscous shear at:least a portion of the viscOus material when there is relative lateral movement between the first attd. second glass sheets;:and at least one barrier whose configuration constrains the. viscous material. Sealing the edge the vacuum insulating glass unit in this embodiment Can be accentiplishedõ for example, by 'pumping the viseciu.$ material in between the first and second gl.ass'sheets 'through oneOr more entry holes disposed tilong the periphery of at: least one of the first and 'second glass sheets;
directing,..00 a: pressure differential,. the viscous material to flow to one or nore exit holes :disposed along the periphery dot lost one of the first and second glass. sheets;..a.nd sealing the entry and exit holg.S. An example of a Met1 od. of forming an. edge seal in:accordance. with this embodiment is. shown in FIGS:, 13 and 14, and is described in 1-4.re:filer detail in the Detailed Discussion section, below.
BRIEF DESCRIPTION OF IDE DRAWINGS:
[00891 The figures listed below relate 0:various embodiments of this invention or act as aids to reference those drawings.
10090I FIG. I i.s not Meant to represent a particular enthodiment of this invention. FIG.
1 is a plan vieW ofa generalized schematic depictino the basic elements of a.
VIG unit that is used to reference the location of the .cross sectional drawings herein that do depict particular embodiffiCil t.S. of this invention.
100911 FIG. 2 is.a. sectional view of FIG. 'I
[0092j FIG. 3 is .a.trosS sectional view (as referenced. by FIG. I) of the edge region of a V IG unit actording to it first embodiment of this .invention under the condition that the ambient air.temperatures.oneither side of the unit are the same, .as ).koold occur if the unit.
was in service in a budding and. the indoor and outdoor temperature.s..were the same.
[00931 FIG. 4 is Li:detail of a portion of the section shriwn in FIG. 3 hut 'with greatly exaggerated scale:in one area for clarity, E00941 FIG. :$ is the Otte CrossseetiOnal view. as FIG.. 3 under the condition that the ambient air temperature on ooeside.of themitls:lower than on die other, .as.
WOuld occur if the unit was in service and it was colder outdoors.
[00951 FIG. 6. is .aSectional plan view of a VIG unit with ao edge seal as depleted in FIG. 3.

[00961 DIG. 7 is the same cross section as :in FIG. 3 hut with modification to iore fully delineate the scope of the invention.
100071 FIG. 8 is A crOss'iSettionai view (Eal.reiscrtmced 'by FIG, 1.) of the edge .region of VIG unit according tn a.second effibudiment of this invention under the condition that the ambient air temperatures on either side of the unit are the same, as would.
occur if .the unit.
wits in service in a building and the indoor and outdoor temperatures: µvere the same.
100981 FIG. 9 iS Across Sectional view (as refereked. b-y FIG. 1) Of theedge.
region of a VIG unit according.tozthird 'embodiment ofthis invention under the condition that the ambient air temperatums on 'either sidea the unit are the sae. . would occur if the unit was in service in a building a.nd. the indoor and outdoor temperatures :were the :some, [00991 FIG. 10 is a cross septionai viow as rekrenced hy FIG. .fl ofthe edge region a VIG unit according to a tburth embodiment of this invention under the condition that the ambient air. temperatures o.n either side ofthe unit are the same, as would.
occur if the unit .wasí SentiCe in a building:and the indoor and outdoor temperatittes were the same.
NUM FIG, tt shows a schematic plan.view: of a WO unit indicating that the edge .seals disclosed herein need not run continuously:around the edges of a VI,(ì
MA and that they may be discontinuous.
101011 FIG. 12 is a seetional view of FIG II.
[01021 FIG. 13 is a schematic plan view of via unit that diagrams a method of assembly .for the .0dge seal. depicted in FIG. 3 through FIG. 6, [01031 FIG. .14 is a sectional view of FIG. 13.
101041 FIG. 15 is a -plan view of a polymer sheet that intercorineets an array of polymer .spacers according to:one embodiment of this invention, [0.105I FIG. 16 is a cross sectional view of FIG. 15.
101061 FIG. 17 is the cross sectional AM of the polymer sheet in FIG. 16 placed on a glass sheet according to one embodiment of th is invention.
[01071 FIG. 18 is -the cross. sectional view (Anti, .17 showing.howa polymer Sheet may be rernovcd from _integrally formed polymer spacers ac.cording to one=
embodiment of this invention.
101081 FliG.1.9 is a cross sectional view ef a polymer :sheet. that iniereonne.cts an array.
of polymer spacers in a punch and the used to remove the polymer sheet from the spacers and press them to a. glass sheet according to one embodiment Of this invention.
[01091 FIG. 20 is a cross sectional view t'rf a. vacuum insulating glass unit with viscOus edge seal Showing a polymer .Sheet with polymer spacers where the sheet is essentially continuous and not .removed from the spacers in the final VIci assembb., according to one embodiment of this inve.ntion.
101.101 FIG. 21 is a cross settional view, of a polymer sheet with integi*
spac..,ers positioned by a jig With a glass sheet loWered onto the polymer spacers.
according tO One embodiment alibis invention.
[pm] FIG. 22 depicts.a.support spacer for kt V1G unit with a slape to .minimize heat conduction and provide. lot $tahility amording to one embodiment of thìsinvention.
Il11.121 FIG. 23 depicts a support spacer for a V1.6 unit with a shape to minimize heat conduction and provide !for stability acCording to 011.0 embodiment of this invention, [01131 FIG. 24 depicts:asupportspacer fora VIG unit xvith a shape to minimize heat eonclueìon and provide forStability.according toone einbodimentof this invention.
[01141 FIG. 25 depicts a support. spacer for a VIG unit with a .shape to minimize heat conduction and provide. for stability .according to one embodiment of this invention.
101151 .F1G. 26.depicts a plan viewof a \I'M unit with a 'mesh support spacer according to one embodiment of this invention.
[01.161 FIG. 27 is a cross sectional view of FIG. 26.
[01171 FIG. 28 depicts a plan view of a VIG unit Nvith mesh -removed during window asacathly aceording to one ernbodiment Of this.invention, lO118 1 FIG, 29 is a crOss settional VieW Of a V IQ unit depleting !Iowa viscous material may be pressured into a cavity between the glass.shuets of a Vi.6 unit according to one embodiment of this in.ventionõ
101191 FIG. 30 is a crcisS Sectional viewof.a 'VIG unit with a. Cathy comprising MU Ile sub.-cavities acconling to one embodiment of this invention.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THIS
INVENTION
101201 FIG. I is. aleneralized schematic plan view depicting the basic .elements of a V1G unit and is used to reference thelocation of the cross:sectional drawings-herein that 'depict particular embodiments of this invention. FIG ..2 is a cross: section 4:3f FIG.
Referring.to FIGS. I and 2, a VIG unit comprises twosiass Sheets 101 and102 with a vacuum space 103 in between. 'The glass shwts: are separated.byspacers 104 which may .be 'small discs. made of PE .Polyethylene. Although removal of afly onespacer104 will not necessarily result in the collapseof a portiOn of vacuum space I03, it can be said that every 'spacer 104 contributes to the separation of glass sheets 101 and 102 and therefore to the maintenance cyf the ,,,,tteutim space.1.03 by resisting eompressioneaused by atmospheric pressure. The vacuum space 103 is sealed around its perimeter by an edge seal 105.
101211 An alternative to it Multiple spacer tirrangernent may be a unitized or single spacer comprising a screen or mosh form to inseetSereens bat with larger grid spacing. The diameter or cross..sectional dimensions of the filaments of such a screen spacer may µrquy so as to lirnit heat transmission surface area in contact with the glass sheets and so as to allow. gas transmissionbetween gid square during pumping down 'ofthe vacuum Sp8Ce. A unit spaeet tnay Irwin& perirrieterstrip. elements with wider widths than the grid filaments: Carbon fiber may be one tifmany:Suitable mat-CH.0S fr such a single unit screen spacer. ksereen spacer May,' drasticallyredueernaterial and assembly costs and may be particularly well.snited to take advantage of a viscouss edge seal.
101221 FIG. 3 i.s. erosS sectional view (as Telliirenced by FIG. 1) of the Op region of :a V. unit according to a first embodiment of this invention showing an. edge seal that comprises viscous material 302 With low gaSpermeability and barriers. that constrain. viscous material 302 that include: glass .sheets 3113 and'304:..strip spacers 305, 306, 307, 308.; and lubricating low .vapor pressure viscous barrier 309. Strip spacers 305, 306, 307, 308 ma.y be.
made (1.1'420 stainless steel, \vhich has virtually the sarïie. coefficient of thernial expansion as soda lime glass, or they may be made of PE Polyethyleneur other suitable pOlymers.
[0123i FIG.3 shows the edge:. region under the condition That the ambient air :temperatureson either .side of the unit are the same, .as..would occur lithe unit was. in. service in a building and the indoor and outdoor temperatures were the same.
Glass.sheets 303 and 304 are separated 'Lly:an array of spacers 310, The thickness of spacers 310, and therefore the distance between glasssheets 303 and 304, may be approximately 0.02. inch, Spacers 310 may have ii.Variely of shapes and be made of a variety of material's. The niaterials may be metallic, polymer, ceramic.or composites oft.hese inaterialsõ.A. prelthed spacer 310 is a disk m.adeof a polymer that vvill µvithstand the compressive forces placed on it, that has low thermal conductivity, .and that:will tend notto scratch glaSs..sbeets 303 and 304. Spacers 310 alay be affixed to one of the atass sheets 303 or 304 so that they cannot migrate and. yet allow relative lateral moyetnent between glass sheets 303 and 304 with little resistance -In addition to being highly creep resistant, PE Polyethylene is :self I ubricatiag and may bea suitable material -for spacers 310. The:space 311 between glass sheets 303 and. 304 is a vacuum* a pressure lessthan atmospheric. pressure,. preferably less than .10- torn The low pressure vacuum space 311 essentially eliminates convettive and conductive heat transfer through that .space: Strip spacers 305 and 307 may be cemented or otherwise permanently affixed .to glass sheet 303 and strip spacers 306 and 308 may be. similarly affixed to glass sheet 304. 'Both strip spacers 305 and 306 are proximate the edges of glass sheets 303 and 304 and in between glatis 'sheets. 303 and 304. Strip spacers 305 and 306 may continue: in this manner areund both glass sheets 303 and 304. The thickneSS of strip spacers 305, 306, 307, and 308 may be the same and each equal tourie half the distance between glass sheets 303 and 304.
Thereforethe combined thickness Of spacers 305 and 306 may be equal to the distance between glass sheets 303 and 304 and the thickness Of Spacers 310, Str.ip spacers 307 and 308 are similar to strip spacers 305 and 306 except. that they are situated further in from the ..edge Of the glaSs'sheets and there are no discontinuities as they continue around glass s.hects 303 and 304. The distance between spacers 305 and 307 may heObrexamplc, approximately two inches. For some applications vhere the rate of gas permeation through .viscouslttaterial 302 musl be kept. especially iow, ascot example when long service life is:.song.ht without purnpiug doWn through a pump out port (not. pictured) every couple of decades, the distance betWeen strip spacers 305 and 307 inaõy be ten inches or more: These midribs: of the edge where the seal is present could be huriettwithin a wall cavity with insulation on eitherside.
Strip.spaeers 305 and 307 may he one half inch wide and strip .spacers 306 and 308 may be one quarter inch wide. Strip'spacers 305 and 306 may contacteach other in the sense that each exerts a reaction force against the other but they are aot .aftixed to one.. another and are thereforee free to move laterally relative to one. another. Even though .there may he an additional material or compound between strip spacers 305 and 306 they are still cc.insidered to be in contact. In the same sensestrip spacers 307 and 308 may contact each other hut are not affixed to one another and are therefore free to move laterally relative to one another, 'When glass sheets 303 and 304 are at the same temperature the center lines 312 of strip spacers 305 and 306 may elOsely 'coincide.
101.24j Stilt referfing to FIG. 3, gases 3.13 at higher pressure 'than the pressure 'vacuum space 311 inay permeate through at least. a..portion of viscOus material 302 at such a loW rate as to provide a long service life for the vacuum insulating glass unit or at a rate that extends service :life to anywhere from 0 to. 20 years a 'which time the..vacuum space311 may be pumped down to:its ìflítia1 loW. vacuum pressure through a 'permanently attached. or temporarily attachable pump out port not pictured').
[0.1.25] Still referring to FIG. capping all of the edges cif glass sheets 303 and 304 is ait end cap 315 that may be pressed on and that surrounds The periphery fills VICi. unit.. In addition to shielding the edge gap 316, end cap 315 applies a Clamping force against Oast;
:sheets 303 and 304 so as to maintain sufficient pressure on 'strip spacers 305 and 306, fO!2 61 Stili referring: to FIG. yiseops barrier 309 prevents viscous niaterial. 302 with low.gas. poineabil by from contacting spacers 305, 306, 307, and 308 vhere it could work itS
way between thosi sp4peM and increfiSC fli060111/1 forces, The lubricating low vapor pressure viscOus barrier 309 resists long term pressure induce(' creep behveenstrip 'spacers 307 and 308 %villa are under tight contact with each other in:excess.of atmospheric.
mssure.
f01271 Lett he the thickness. ola sheet of glass.and let there he an .arbitrary x and y Cartesian Coordinate Systc..tm in a plane stibstantially parallel to the laces of the glass sheet. In order to achieve atm-What-in:Sly 'tight gAr= free contact between strip spacers. 307 and 308 and strip spacers 305 and 306 the gradient magnitude IV' ja(itlyiat any point around the periphery of glass sheets 303 a.nd 304 should be sufficiently small such that any irreguloritiesTepresented by 1V.ti will -be pressed out through flexure caused by the .eompressive ssure ofthe atmosphere Over the eitaCtrated space 311 and by the clamping foree Of cap 315 Fortunately Modera plate glass. used for .glazing is.
produced by the Pilkington flnat procesS. Le Hourhis (2008, p.35-36) states treferenees.
'cited: other publications):
The process was developed atter the:8econd. 'World. War by Britain's Pilkington Brothers It was' ttvol &aim in Rat glas$ productiOn 'Since polishing Of the glass plates was no longer necessary. . In 1959, after seven years of ekperimen tatidn and an inVestment f7 níl ìnrìPilkingtOn Ltd introduced this .economieal means to produce distortion-free glass. :Nowadays =a1tn0St 90% f Alt soda-lime-silica :glass .is exclusively produced in this. way , [01281 The Pilkington float process automatically produces stock plate glass such that 1.7.ti is sufficiently small to .aehieve the necessary tight continuous contact between strip spacers 305 and 306, and strip spacers 307 and 308. ThicknessuleaSurements of various specimens of plate glass from .Varioussources usinga eigìtaì mierom.eter reading to :0.00005 inch indicate that stOCk unaltered float glasS will meet he necessary criteria. for [01291 Still referringto FIG. 3, a cavity is defined by the cOntinuous region bounded by glass sheets 303 and 304 and by viscous barrier 309.
[01301 FIG. 4 is a .detail-of a portion .of the section shown in FIG, 3 that greatly exaggerates the scale attic surfitee texture 317 0. strip 'spacer 308 that is in contact with strip spacer 307õ The .surfacetexture 317 may be ground, sada, gmoved, or some other category of rOtighness or corribi nation of smoothness and roughnesswith very sMall amplitude 318. Fnr example, the amplitude .318 may tie on the. order of 0Ø004 Melt The net forecon strip spacer 308 inay be nine pounds per lineal inch of spacer. lithe width of strip spacer 308 is one quarter inch this would resuit in a presstire. n strip.Spaccr 308 of36 psi.
Most of this presiture would be resisted through:the high point contacts of -the roughor.grooved surface, texture 317 .of strip spacer 308 .ort strip spacer 307 and not by the thin film cif viscous. barrier 309 that will become -partially interposed between strip spacers 307 and 308 due to relative lateral mevementof giaSs sheets 303 and 304. .Therelbre the pregsure of the thin filraof viseOtis barrier 309 that will become panially interposed between strip spacers 307 and 308 will not &wed the pressure of Yiseons material 302. By limiting the piretiSare of the thin film of viscous .harrier 309 between .strip spacers 307 and 308 to that of viscous material 302 any.
tendeney to "pump" viSeous harrier 309 between spacers 307 mid 308 and into vacuum sace 311 is mitigated. Thcrough surface 317 increases the frictional forces on the thin film of ViSCOUS barrier 309 between spacers 307 and. 308 and thereby increases= the.
resistance of=
viscous; barrier 309 to creep between spacers 307 and 308 and intO evacuated space 311.
[01311 Obaoing theological tests.at three:tirnesatmospheric pressure have yet to reveal any Sign of creep of a preferred material for visc,ous barrier 309 through a gap.larger than that created by the rough surface of 317.
101321 FIG. 5 is the Same cross. sectional view as FIG. 3 hut under the condition that the ambient air temperature on one side of the Mit is lower than on the other aswould occur :if the unit was itt service and Awes colder .outdoors. When glass sheets 303 and 304 move laterally relative to one aother 320 as a result of thermal .strain .or for any other service related reason, viscous material 302 undergeies.viseous.Shear through a shearangle 319 with very little shear stress while maintaining adhesiontoglass sheets 303 and 304 under the no-slip:condition forviScrius fluids. in this manner viscous material 302. cannot fail as a Seal becauseoftensile, rupWre, adhesive: faltureõ..cold brittle fracture, material breAdown, strain hardening, de-lamination, fatigue, bond faihtre,..Shear rupture, puncture., or by inducing, failure streSsesin glass sheets 303 and 304. 'The low shear stress ussures .thatglasS
sheets 303 .and .304 will not bulgt.',. Because the .shear is viscous shear, where shear stressis a function of shear rate, 'once relatiVe motion between glasS:Sheets 303 and 304 .stops there ism shear stress and of course no shear stress: induc.ted.eompressive.or tensile stresses in glass sheets 303 and 304. This is not the case for elastic materials where stress persistsafter motion stops whether or not the strains are in the elastic or inelaStic ramie. Therefore, given a viscous edge seal as disclosed by this embodiment:, stresses in glass.sheets 303 and 304 are il6t a function of static relative lateral displacement 320 between glass sheets 303 and 304.
Therefore the si-0 of a V.tG unit with :a viscous edgeseal may be limited only by the praedcal sizeof produeingglass sheets 303 and 304. This is not the case for thc metal edge seals disclosed by Pub, Nos. 'US:2008/0166570A., US. 200910155499 AI US 2010/0178439 A I , and US

2O/0034996 Al, Where. the. edge seala are Subject to elastic and inelastic stress and strain and limited by Strain at ultimate strength An edge seal desiim that does not limit the size: ofa VIG unit is significant, Larger Vi( units are more energy efent because per square. ft: of ,.virtdow there can be less lineal footage or heat conducting edge seal.
[01.331 Referring to .FIG...5, when lateral relative:movement 320 occuB
between glass.
.sheets 303 and 304 as i result of thermal. strain the space bounded by glass sheets 303 and 304 and spacers305, 306. 307, and 308 does not change significantly and by geometric proof the volumesoceupied byviscoas barrier 309 do nOt significantly change.
Therefore given this type Of relative movement, visa-ins harrier 309 redistributes to neW.Shapes within the same volumes.
101341 Changing indoor and outdoor temperatures will cause the nets of a V1G
unit to expand and contract differentia ily, includingviscous material 302 and vispons barrier 309.. As a result, the dimensions of the spaces that contain viscous material 302 and viscous barrier 309 will change_ To accommodate this, .viscous .material 302 has a.free.surface 321 across the top of the unit as depleted hi FIG, 6 that rises and fa% as does the five 'surface Of ak 'fluid whose container changes dimenSions, Also shown in F. 6 is a break 324 in strip spacer 305 to allow pressure equalization, 101351 By way of illustration only, in some embodiments, the viscous material used M
the edge seal win ha ve.a gas permeabiliy.ofno greater than about 1,000,000 (centimeter3 =
raiIin'ier/rneter = day = bar) for oxygen gas: at 20. .C, asnicasured by ASTM
D 3985. This includes embodiments hi Whet theyiscous material has a:gas permeability of no greater than about 100:000 (centimete?' = .mtninta bar) for oxygengas.at 20 9C, as measured :by .ASTM
I) 3985, and further includes:embodiments in which the viscous material has a gas permeabilitrofno greater than about 10,000 (centimeter- = intni.m' d r bar) for oxygen gag at 20 C, as measured by AST J) 3985õand further includes embodiments in which the viscous Material has a gas permeability of no. greater than about poo (co timeter3 - mm/In2 -d = bar) for oxygen gas a.t2011; as. measured by ASTM D 3985..
[01361 The d.esirable. viscosity of the low permeability viscous Inforial may vary over a wide range depending upon a.variety of factors., including. the method used io apply or dispose, the viscous material in the edge.seal. Byway of illustration only, in some embodiments, the low permeabiiity viseoug Material will have a viscosity of no greater than about 90,000,000 (mP.a. = s) At 20"C. This incitid.es embodiments: in-which the low permeabty viscous material lias a viscosityof no greater than about 1,000,000 (mPa s) at 20 further includes. einbodimentS in which.the low permeability viscOus material hits a visosity of no greater than about 10,000 (mPa s) at 20 "C, still further includes.
embodiments in which the low.permeability viscous material has a viscosity dm) greater th.an about 1,000 (mPa s).420 . C, still further includes embodiments in which the low permeatyviSeous tnaria l has a. viscOSity Of no greater than about 100 ((ea =
s) at. 20 ';T:.`.
and still further includes enthodiments in -which the low permeability:viscous material has a viscosity of no greater than about (inPa s)=At 20 C.
[01.371 A viscous material with low gas:permeability suitable for material. 3 be.
a cold flowing NeNvtonian Htiìd sueb as a. loN.A, to medium moiceolar weight polyisobutene or KB. The gas permeability of polyiSobutene isoneof the lowest: fOr pelymers and againSt which the permeability of other ptilymers is compared, in the form of elastic butyl rubber it lines all tfits.to prevent pemteation of air out of the tire8..P.19 is inert, -nontoxic, aid -stable indefinitely, Specifically,RIB -manufactured by the chemical company BASF
under the trade name Op-panol B1 0 has .suitable viscosity, Other molecular weight grades of PM may be suitable..for this invention. For example, BASF .makes a family of low molecular weight Pt Ws under the trade name GliSsOpal. Under some embodatents Of this invention Glissopal or some formulation:combining Glissopal and an Oppanol B may be all'Optilind .ehoice for .the viscous material 302 with low gas permeability. The choice .may depend on the particular barrier or harriers used to segregate the P19 from the evacuated space 311 and or on the particular method used to -place the PI9 into assembly. Oppanol BIO has annosph.eric gas permeability on .the order of 1 0716.cmnanitert12,Sec-torr). This compares favorably with the gas permeability of Metals 'IV etri3-min/(cm'see-torr)., and of glas5es10- to 10" 13 crit''-intnitem:2'sec,torr).
101381 Given the metal and ,solder glass edge.s.eal thickneSses di sciosed by the prior art, a two inch wide strip of viscous material 302 consisting of .1:911 would .have a reduced rateof permeation compared to the metal seals. and an increased rate of permeation .relative to the soldettlass seals of only a factor Of tem Given that the edge Seal accounts for only 1/1000 to 115000 of the permeable surface..of a vacuum insulating glass unit, any loss of service life of a IG unit with a viscous NB edue seal, compared to a unit Nk,ith a. solder glass edge seal, would be negligible.. If a. Via unit has a permanently attached orternporarily attachable pump out port to .whieh a. vacuum pump can be .attached in order to pump down the vacuum. every couple of decades then die difference betwee.n the permeation rates .of a:solder glass edge seal and a two inch wide viscous edge seal composed of PM is inconsequential, 101391 Oppanol Bi 0 is aNewtonian -fluid, .A Newthnian fluid is one where shear stress is.proportional toShearrate. Theconstant of:proportionality is defined as the material's.
viscosity, Oppanol B 1 0 were used.for the embodiment shown in FIG. 3 with a gap of 0.02 inches between glass sheets 303 and 304, shear stresses.eaused. by Otani-rig temperature differentials betvveen inside and outside While the 'unit IS in SeNiee would reStilt in tensile and 'compressive fore es in glass. sheets: 303 and. 304 mi. the order of fractions of a pound force -per 'lineal inch of glasti edge.
[01401 Opal 0 ahts:cold flow,. Unless confined, arty force exerted on. it will cause itto flow and keep flowing. For example,. if a eontainer of Oppanol :B1.0 is tipped over without a lid its contents-Alit-Slowly spill out Like water it seeks its Owrilµ',.vel and exerts hydrostatic pressure. If an objet with greater specific gravity is placed on the surface of OppanoI 10 it will slowly sink to the bottom.. If the object's specific gravity is less than Oppanol B10 it will float on the surface.
[01.411 The term "visepus buri'ier' s used to refer tria viscous material tht May be used in an edge seal along svith the low permeability viscous 'materials described above. This 'term is usedfiir clarity to distinguiSh the two materials in those embodimentS in which they ate used -together in an edge seal: Byway of illustration only, in some embodiments, the ViScous material of the 'viscous barrier win have a vapor pitssure ofno greater than about 10- torr, This includes embodiments in which the viscous material of the viscous barrier has a vapor pressure Of no greater than about torr, and further includes embodiments in which the viscous material of the viscous barrier has a vapor pressure of no greater than about 078 tom A Shitable .material for Viscous barrier 309 is the high teinperaturc Vacuum grea56 manufactured by M. & ì Materials.Ltd underthe trade name. Apiezon H. Apiezon is relatively stiff grease.with a vapor pressure at 20 degrees. C.':elsitts of .1.7.X 104tott Apiezon II is inert and stable indefinitely. It will not melt and gets stiffens its temperature increases.
This...particular characteristicis important becauseitwi1 not: soften if, for example:, during Vi unit lahrication polyisobuterte at an elevated temperature and lowered ViS:cositY is pumped between glass Sheets 3tI3 and 304. .Also of importance i.s..the fact that the specific.
gravity. of A.piezon H ìs virtually identical to that of polyisohutene.
[01421 Vaeuum.greases such as Apiezon are 'primarily employed in vaeuuntseating applicatiOns. involving .fixed. Or gasket seals:or in rotary motion seals and \ vhere the vacuum space is imder continual or short term i.titermittent pumping to maintain the vacuum at the desired level. They are. also us e,d in sealing ground glass stop cocks used in. chemistry glassware. But here again the vacuums are maintained fOr short periods:or are under .continuous .or.ShOrt term intermittent pumping .to maintain thevacuum. The importtme of.
'such .gases has to do with their lOw ..vapor preSsure and lubricatingproperties and with their ability to at least .tvdtiee gas leaking, thrciugh the surface. imperfections of-rings and gaskets.
Greasegare generally not Ne\vtonian fluids and under shear their shear stress is not proportional .to therate ofs.hear but instead the relatiOnship between. Shear StresS and shear rate for greases takes more cOmplicated. nonlinear forms, [0143l Useof :Vacuum greases in vacuum sealing applications does :net suggest their use as a viscous material for edge sealing IG units. To the contrary, the types:of vacuum sealing applications:where ntgrease is employed suggest.that it is not a viscous material suitable for restricting the permeation of gas through a VIGedge seal.
[111441 FIG, 7 is the same cross:section as in FIG. 3 but with modification to .more fully delineate thescope of the: invention. The. modification ìs that thestrip spacers 305 and 307 are joined by a strip of the same material 63 become .one:strip spacer 322 and strip spacers.
306 and 308 are similarly Joined tbeCOMe one strip spacer 321 Viscous 'low gas permeability material 3I2 is then no longer in contact Nvith glass sheets 303 and 304.
Unitizing.strip spacers .3i95 and 307 and strip spacers 306 and 308 may speed V.16 unit aSsembly times and reduce thc. areapresented by viscous low:gas permeability material 302 forgas to permeate through, A cavity is defined by .the continuous region bounded by strip.
spacers 322 and 323 and viscous barrier 309.
191.451 FIG. 8 is:a. erosS.sectional vie* (as referenced. by 'FIG. 1.) of the edge region .of a V IG unit according to .a..second embodiment of this invention showing..an edge.seul that 'comprises viscous material. 802 with loW. gas permeability and barriers.to constrain ViScOus material 802 that include: glass sheets 803 and 804; strip spaeers. 805, 806, 807, and 808;
lubricating low vapor pressure viscous barrier 809; and end cap 815. FIG, 8 shoWs the edge region under the condition that the ambient :air temperatures on either side of the unit are the same, asveould ()pour -if the unit wash) service in a building and the indoor and outdoor temperatures' were thesame. Viscons.materi a I 802 with low gas permeability and viscous barrier 809 .marcontinue unbroken around the Wee. regions of glass sheets 803 and 804. Strip 'spacers .805, 806, 807, 808, and end cap 815 may:continue unbroken around the edge regions of glass sheets 803 and 804, End cap 815 may place iclampinaorcompressiVe force against glass sheets 803 and 804. Glass sheets 803 and 804 are. separated by an array of spacers 810 and by strip spacers 813 and 814. Strip spacers 813 and 814 ma.y continue unbroken around the ettge regions: (if.glaas:Shects 803 and 804. The space 811 betweettglass.Shects 803 and 804 isa vacuum at apressure less than atmospheric, preferably less than I 0-;
tom The low pressure :vacuum spec 811 greatly reduces=convective and eanductiVe beat transfer between glass sheets N3 and 804. Strip spacers 805 and .807 may be eemOnted tO glass.
sheet N3 and strip spacm 86 and 808 may be cemented to glass.shect 804. End cop 815 is..free to move, relative. to spacers 805, 806, 897, and 708. When there is relative lateral movement between .glaSS Sheets 803 and 804 sornepOrtion of visccius..material 802 will undergo viscons:shear. .A
first cavity is defined by the. cOntinuous region bounded by viscous barrier 809, glass sheet 804, and end cap 815. A.Second cavity is defined by the ebrainuous region bounded by vs barrier 809, glass sheet 803, and end cap 815, [01461 FIG, 9 is.4 cross:sectional view (asrefe. fenced by F1G, of the edge region of V. unit according to 4.:third embodiment ofthis inventi n. showing an edge seal that comprises viscous .material 902 with low gas permeability and barriers to constrain ViSMUS
material 902 that include: glass sheets 903 and 9:04, elastic :membrane 905, and end cap 906.
Elastic membrane 905 .is cemented or ntherwise 011)4 o glass.Sheets 993 and 904. Elastic membrane 905 need not have low gas permeability so it can be made of a material and with a thickness that stretches .eosily and with very little flirce. FIG 9 shows the edge region under the condition that theamhient ai.r tomporaturesOn eitherside Of the unit are thesame as.
would occur if the unit was in service in a building and the indocir and outdoor temperatures were the Saftle Glass sheets 903 and 904 are separated bran array of spacers 997 and by strip spacer 908. 'Viscous material 902, elastic membrane, 905, end cap 906 and strip spacer 908 may continue unbroken around the edge regionS olglass sheets 903 and 994. 'The space 911 between glass sheets 903 and 904 :is a vacuum at a pressure less than atmospheric, preferably less. than 104 torn The low pressureviieuum space 911 greatly reducOµ
edriVectilT and.
conductive:Twat transfer between glass.sheets 993 and 904. End. cap 906, may place A
clamping or eomprOsive force against glass Sheets 903 and 904. End c:ap 906 is not affixed glass.Sheets 903 and 904 and is .free.to move relative to glass.sheets 993 and 904. When thereisrelativelateral movement between glass sheets 903 and 904 some portion of viscous material 902 will undergo viScoos shear, A Cavity is defined by the continuous region bounded.by end cap 906, elastic membrane 905, and glass sheets 903 and 904, toi47i FIG. 10 is .r cross sectional view .as referenced by FIG, 1) of the edge region of a VIG unit according toe fourth embodiment of this invention showing an edge.
seal that comprises viscous:material 1002 with low gas permeability and harriers to constrainviscous material 1002 that include: glass sheets 1003, 1004, and end cap 10051.
Viscous material with kw gas:permeability:1002 and end cap 1005 niay continue unbroken around tile edge regions ofglass Sheets1003 and 1004, The space 1006 between glass sheets:1003 and 1004 is a va.euurn at a pressure leSs than atmospheric presstitte, preferably less than I 0-4 tOrr, The lOw pmsure vacuum space 1006 greatly rcidt.teeS convective:and ccinductive heat transfer between glass sheets 1003 and :1004. Maintaining :separation be veer Wass:sheets 1003 and 1004 are micro sized spacers 1007 the may be made of, for example, nanoparticles.
nanotubes, Viscous Material 1002 is prevented from creeping intOspaCe 1006 by surface tension et the leading edge of material 1002 that is botmded by vacuum space 1006. This is made possible by the eMremely ilbse sgacing Of glas sheets 1003 and 1004. When there i.s relative lateral movement between 'glass sheets 1003 and 1004 sotne portion elviscous material 1002 will undergo viscous Shear, :A cavity is defined be the continuous region bounded be end cap 1005 and glass sheets 1003 and 1004, [01481 FIG, 11 shows a:schematic plan vi .o'a VIC/ unit with a vacuum 1101 and an array of spacers 1102 between glass sheets 1103 and 1104 as depicted in FIG.
12,, which is a M(1101181 view ef FIG. 11. CilaSs. Sheets 1103 and 1104 are rig itliy joined to one another at 1105, Edge seal 1107 may be any (Atte first through fourth embodiments disclosed 'herein:
Glass sheets 1.103 and 1104 are free to expand and contract independently' t-If one another yet remain fixed at point 1105. The tigid contact point 1105 proventt Wass Sheets 1103 and 1104 from "walking" their Way out of registration -with one another as a result of repeated. cycles of expansion and contraction of glass Sheets 1103 and 1104, The embodiniCtIt of a VIG unit as disclosed by FIG. 11 underscores that the viscous edge seals as disclosed herein need not be continuous and without break, 101491 FIG. 13 is .a sacmatic plan view of a VIG unit that diagrams a ROCeSfi suitable for the first embodiment, herein depicted in FIG, 3 through FIG 6, for -placing a viscous low gas permeability material 1306 into assembly betweeo glass sheets 1301 and 1302. FIG. .14 is a section of FIG. 13, Glass sheets 1301 and 1302 have a vacuum 1303 in between them and are separated by an array of spacers 1304. The ass by proeeSs is as followS:
first, glass sheets 1301 and 1302 are placed together so as to sandwich all of tile spacers between them;
second, edge caps, 315 in FIG. 3, are:pressed onto the edges; third, viscous low gaS
permeability material 1306 is pumped through hOles 1307 in glass sheet 1302 while maintaining lower pressures at holes1308 fourth, Vifi:COUS material 1306 flows 1309 toward holes 1308; fifth, after the viscous material has been placed, holes 1307 and 1308 are sealed with caps:

10150I Still referring to :1.3 and I. (me as.sembly proa.ss is as ibliows:
&ass sheets 1301 and 1302 are placed together so as to sandwich some or all of the spacers betWeen them; seeond. the central cavity containing the support spacers is evacuated. to a !matte leSs.tham atmospheric; third. the caVit:µ;' -to: be filled with a ViStOUS material in evacuated to: pressure less than atmospheric; fburth, viscous low gas permeabty material 1306, which ha si beer!. &gassed ',aid or outgassed in a vacuum autoclave or by other methods, presSed through holes 1.3t7 i glass sheet 1302 while maintaining vaetnim pumping at holes.1308; fifth, ViACOLIS materia1.1.306 flows.1.309 toward holes 130k sixth, after the viscous naaterial has been placed. holes1307 and 1308 arc Sealed with caps.
[01511 FIG. 15 depicts a.pkm view of a polymer sheet 140i with integrally formed polymer spacers 1402 aceording to one embodiment of thisinvention. Polymer sheet .1.401 may be formed siMultaneotisly With polymer spacers 1402 by injection molding or compression ITIOlding techniques, Perforations 140 may be. -formed in the same press and may represent discontinuities in polymer sheet .1401. Regions 1404 where polymer sheet 1401 connects:to or transitions. to polymer spacers 1402 maybe-thinner than other regions of polymer sheet. 1401. FIG. 16 is across sectional view. of FIG. 15 and reveals that regions 1404 where polymer Sheet 140.1 connects to or tranSitiOnS to polymer spacers 1402 ntity be thinner than. 'other regions of polymer sheet 1401. FIG. 17 is across Sectional view depicting polymer Sheet. 1401 with polymer spacers 1402 placcd such that polymer spacers 1402 may be in contact with glass sheet 1405. Prior to polymer spacers 1402 being plaeed on glass sheet 1405, end faces 1406 of polymer spacers..1402 that may contact glass sheet 1405 may be charged with an adhesive that may be lowoutgassing. According to one embodiment of this invention FIG. 18 d.epicts how polymer sheet 1.401 may be removed f:rom polymer spaCers .1402 by pulling 1407 on polymer stet 1401. leaving polymer spacers 1402 adhered toglass sheet 1405. Removal ofpolymersheet 1401 from polymer spacers: 1402 may be, aidrd. by thinner regions 1404 and by perforations 1403 depicted in FIGS. 15 and 16.
[01521 FIG.. 19 depicts a.sectional view c,1 a poly-111er sheet 1401 that intercontwas an array of polymer .spacers 1402 .that may baveheen -63/inedby. compression and r injection molding techniques. Polymer sheet 1401 and polymer spacers 1402 may be set in a die 1410 that niay contact glass..sheet 1405. Another clie:or jig 1411 marsiton top of polymer sheet 1401. Punch plate 1412 may drive down 1413 on polymer spacers 1402, removing polymer sheet 1401, and pressing polymer spacers to glass. sheet 1405 where:they .may &may not be adhered to glass sheet 1405 by an adhesive that may or :may not he low outgAt ing. Punch plate 1412 may contact di.e or jig 1411 in its stroke Cycle pressing polymer sheet =14O1 to die 1410 in order toobtain..a clean. break between sp.aeers 1402 and polynier .sheet 1.401, Punch.
plate :1412 may be or comprise -a. flexible material such as but not limited to rubber. A roller .1414 inay pass over punch plate 1412 stlecessiVOy. rikessing roWs of polymer spacers 1402 to 4111S8Sheet1405 and rethavingpolyther sheet 1401.
101531 FIG. 20 shows a Vii .unit with glass..sheets: 1501 ad 1502 and viscous edge sef.41 1503. Polymer sheet 15.04 may he totally adheral, partially adhered, or not adhered at all to glass Sheet 1502, Support:S.paters 1505 are interconneeted by essentially continuous polymer sheez.1504. Polymer sheet 1.504 and spacers 1505 n-ray .be -formed rinttgrally connected and..simultaneously in the same emnpresSiOn or injeetion molding process, 101541 FIG. .21 is a cross sectional view ea poly.mer sheet 1601 with .integral polymer spacers 1602 positioned by ajig 1603, which has pins 1604 that pass:through holes 1605 in polymer sheet 1601. Gloss Sheet 1606 may be lowered.onto polymer sp.acers 1602, which may or may not be .adhered to glass sheet 1606, 101551 FIG. 32 depicts a detail of=.a.support .Spacer 1632. 'with a flange 1633. Flange 1633 allows. thickness 1634 .ofspacpr 1632 to be increased by increasing stability .against overturning. Overturning moment: is generated by -frictional forceS between spacer 1.632 and glass sheets. 1630 and 1631 when glass.S.heets 1630 and. 1631 .move laterally relative to one another because of di fterentialthernial strain. Flange 1633 allOws remainder :of spacer body, .segment 1636, to have a snuffler diameter 1635: The smaller. diameter 1635 and .greater .thickness 1634 minimizeheat conduction through spacer 1632. Spacer 1632 .may be cemented or otherwise adhered to glass sheet 1631.
101.561 FIG. 23 depiet.a detail of a support spacer 1641 with a tapered side between lass sheets 1643 and 1.644. Tapotd side 1.642 provides a wider base :1.645 to resist an overturning moment while providing for less heatIOSs through spacer 1641 than would occurif'spacer1641 \vas cylindrical with a diameter 1646.
101571 FIG. 24 depicts.a detail of a support spacer 1650 with a beveled. edge 1651.
.Beveled edge 1651 reduces the area Aspect 1650 in contact with glass sheet 1652, which reduces heat loss through spacer 1650. Beveled edge 165.1 alsoreduces the likelihood 'of spacer 1650 being .e.hipped vhen glass sheet 1652 moVes.relatiVe to it. Spacer 1650 may or may not be cernented:or adhered to or otherwise affixed to glass sheet 1653..
[01.581 FIG. 25 depiets a detail Orli-support spacer 1660 that has a square cross section to emphasize that cross sectional geometry :of spacers May .have=varkd shapes and still possess.the attributes of reduced heat .conduction and stability disclosed by FIGS. 22 thiotich 24.

[01591 .Referring to FIGS. 26 and 27, a .VIG unit 1681 comprises two glass sheets 1682 and 1683 scpantted by a vacuum gap 1684 at a pressure less than atmospheric pressure. A
met4h support spacer .1685 in between sheets 1682 and 1683 maintains vacuum gap 1684 by resiStingthe compressive load Ofatm.osphcriepressure. IV14.'sh supportSpacer 1685 tuay :be fixed and immovable with respect. to either glass sheet 1682 or 1683 or may float. between sheets 1682 and.1.683, .A. low gas permeability edge seal 1686 around the periphery of Vì
unit 1681 separates theatmospherefrom vactiUM tap 8=
1101601 Still referring:to .F1GS. 26 and 27.; 11WO support spacer 1685 comprises.support spacers 1687 that. are interconnected 1).y. a mesh.1.688. Support spacers 1687 resistilie compre:ssive load of atmospheric pressure, .M.esh 1688 allows easy and rapid assembly i.rf V{ì unit 1681. Mesh 1688 may be less :thick than spacers. 1687 in a directicn perpenclicuIar glasS sheets 1682 and. 1683. %Trott spacers 1687 and mesh .1688 may include any Suitable materials, In some embodiments spacers 16.87 and mesh 1.688 are made of a polymer. A
suitable polymer is polyirradc.lti some, embodiments spacers', 1687 and -mesh 1688 marbe formed at .thesame time. and. as a Unit a$ in a compression inolding process, Spacers 1687 may be of any suitable size or shape. Mesh filaments 1689 may be daily length or cross section In some eItlboditneints the cross sections of filaments 1689 may .sraty ìri size and shape.
[Moll Referring to FIGS. 27 and. 28. in sotne embodintents mesh filaments 1689 .are removed wholly or in part during assembly .of" unit 1681. FIG. 28 shows a=VIG unit 1681 -with mesh filaments 1689 removed during assembly. Nitesh 1688 .aids in assembly of Vi G unit 1681. nenaust it allowsinany spacers 1687 to be .simultancoasly placed as a 'matt on glass sheets 1.682 and or 1683. Alier a mesh support spacer 1685 is positioned on glass sheet 1682 and or 1683, mesh fî{a.nieits 1.689 may he quicklyremoved by cutting or by:other methods, leaving spacers 1687 on oneor both of giass:sheets 1682 and .1683.
Spacers 1687 m.ay be affixed to one Of the. Wass Sheets 1682 or 1683 or noat.between them SPIlle of the .splicers may be affixed .to glass. sheet 1682 -vhile others are affixed. to 0888.theet: 1683 while sil othersmav float. In soinc.embodiments some of the .filaments 1.689 may remain uncut or partially removed. During assembly of a VIG unit 1681, one niesh spacer 1685 or multiple mesh spacers 1685 may be used.
[0.I.621 Referring to FIGS. 26 through. 28, mesh support spacer 1685 may be placed on a giasssheet168:2 or 1683 with the aid Ora jig that holds mesh 1688 and spacers .1687 and that precisely aligns spacers 1687. Cutting blades 01 a cutting head may run .down the rows of spacers 1687 cutting and removing filaments 1689. 'file blade positions may be adjusted b>,-photo ..54ensors that detect the positions givacers 1687. A cutting head may be used to cut and remove filaments. while a mesh is held in the jig and before the .spacers are placed On .a glass sheet or after a mesh has been placed on a.glaSs.sheet.
101631 Still referring to FIGS. 26 throul.:,41 28, the .atray f spactrs 1687 may be of any suitable geometry.
1016,11 Still referring to FIGS, 26 through 28, mesh filaments 1689 may be removed before or after V10 tmit 1681 is asSembled by. vaporization or :melting through a thermal or other process or by-dissolving. by a liquid or gas einvirontilent or contact µvith such an environment As part Of a vaporization or melting process support spacers 1687 May be shielded from a thermai.source, [01.651 Still ref ìn to FIGS. 26 through 28, mesh filaments 168-9 are equivalent to a sheet that interconnee0 Spacera 1687, 101661 Still referring to FIGS. 26 through 28, tnesh filaments 1689 may .not be removed and 'may remain betWeen glass. sheets 1682 and1683 after Vki=asaembh,,f.
101671 .Referring to NG. 29,. a)./IG unit 1701 comprisesglassashects 1702 and1703 with a VEICQUITI space 1704 at a pressure less than..atinospheric pressure in between them. Ail array (if support spacers 1705 may maintain Separation of glass sheets 1702 and 1703. An edge seal .may.comprise outer Strip spacers 1706 and 1707 and .itine strip spacer s1.708 and 1709, _An .edge seal t-riay furthettomprise lubricating loW vapor pressuMviscous barriers 1710 and 1711.. Strip spacers :1706, 1.707, 1708, and 1709 along with :viscous bathers 1710 and 1711 may define part .of a cavity 1712 between glas5i.sheetS- 1702 and 1703, wflich may include additional sub;,eavities (not shown here), configured to contain a .iovci 'permeability viscous .inaterial. Cavity 1712 may be part of a viscous edge.seal. The.
bounding elements Or barriers that define that part of a cavity in hetWeen the glaSs s.heets of it .unit that is to contain a viscous material aapart oftutedge seal are not limited to. the: grip spat-co:or low vapor pressure Viscous barriers that are recited above and shown in FIG, 29 but may include different, additional, and or fewer barrier elements just so long as.
they:define in whole .t,ir in part a cavity that will contaitta viscousIttaterial.
101681 A cavity containing a. Viseousatnaterial that forms part of an edge seal for a VIG
unit may be entirely between the glass sheetsof that unit as.depicted in FIGS.
3 and 7, it ruay be entirely outside the 'glass sheetsaadepicted ìa FIGS. 8 and 9,11t it may -he partially between and partially outside the glass sheets as depicted in F1( .10.
[01691 A eavitycontaining a Viscous material as part of art edge seal may or may not have its entire vOlume occupied by= that viscous material.

[01.701 Stili referring: to F.G. 29,a vacuum autoclave 1713 illay degass or outs a.
viscous material to be pressured intotavity 1712, A vacuum pump:1714 attached to cavity .1712 through COffileCtions 1715 inay pump (low ity 1712 to a presSure less than atmospheric pressure, After Cavity 1712 has.been.evacuated to a :pressure less than atmospheric pressure, a viscous material may he pressured into. cavity 1712.
including any additional sub-cavities that forM part .of cavity 1.712, tlirough connections 1.716 that may feed directly to vacuum autoclave 1713. The total pressure. or total head.
neceSSary tocapse to of .a viscous material into cavity 1712, iiteluding any additional sub-cavities that tbrin part of cavity 1.712, may be created by, but limited:to, a press, serew, pump.
hydrostatic pressurcõor rotary 'extruder.
[01711 Still referring to FIG. 29, there nlay'be multiple connections '1715 and multiple connections 1716 connected through multiple Openings :1.717 and 1718, 101721 Still referring to FIG.. 29, cavity 171.2, including any additionai sub-cavities that fornt part of cavity 1712, may. not be evacuated to a 'pressure ids than atmospheric beforea viscous material is pressured into them.
101731 Still referring. to FIGõ .24), 0. viscous material to be pressured into cavity 1712, including any additional sub-cavities that form -part of cavity 1712, may .not be degassed :habit being pressured into them, 101741 FIG. 30 depletsa seenari0 where a cavity containing viscous material a part of an edge seal for a VIG unit .comprises a sub-eavily that is disposed between.*
glass.Sheets of the VIG unit in communication with other sub-cavities that are not disposet.1 between the glass Sheets. Referring to 'FIG. 30, a V1G unit includes tiyo glass sheets1815 and 1816 'separated by a vacuum gap 1.817 at a pressure less than atmospheric pressure, Support spaders 1818 that may he affixed to either 'sheet :1.815 Or.1816 in befiiVeett glaSs sheets. 1815 and. 1816 inaintain vacuum gap 1817 by:resisting the compressive load of atmospheric pressure, Strip spacers 1819 and 1821. areaffixed .to glass sheet 1.816 and :strip spacers 1820 and :1822 are affixed to glass sheet 1815. In between strip spacers 1819 and 1821 and strip spacers 1820 and .1.822 and glass sheets 1815 and 1816 is'a .10w permeability viscous material 1823. in betçousi'i'iateriat 1823 and strip spat:tem 1819, 1820,1821 and 1822 is a viscous barrier materia11824, Viscous harrier materia11.824 providesa. vjitOUS
barrier that resists creep between. spacers 1819 and 1820 and between spa.cers 1821 and 1822. ViSCOUS
material 1823 is .also contained .within flexible diaphragin 11.827 and passes through port 1826 in glass sheet 1.815 so that viseOus material 1823 contained in the flexible diaphragm 1827 is:
in communication with visCous material 1823 in between glass sheets 1.815 and 1816.

Flexible diaphragm 1827 and port, 1.826 define sub -cavities of the: cavity 4.,onfigured to contain. The viscous material thatare not between glass sheets 1815 and 1816, while the space.
bintoded by glass. sheets 1815 and 1816 and visootis harrier Material 1824 define a sub,cavity that is between 'glass sheets1815 and 1816. As the vOlume ofviscous material 1823 .expands and contracts with .changing temperatures.. volume compatibility between viscous material l83.and the eonftheg.betv,,een glass .sheets 1815 and 1816 is. maintained by visuous. material 1823 being preSsnred dut and in through pcot 1.826. Rigid cell .1825 contains flexible diaphragm 1827 and IS. evacuated to a pressureless than atmospheric pte,ksure.
Springs 1829 exert preSSure on plate 1828 which in turn.exertS pressure:on diaphragm 1827.
Flexible diaphragm 182'7 may comprise .metal and plastic laminates that .have. low gas and moiature permeability or WI:terminable laminates or coated. materials. The:volume of thesub-cavity defined by fleXible diaphragm 1827 will change RS VESOUS Material 1823 flowain and out of it.
[01751 Any -method to Seal a VIC Unit that comprises two gas sheetS 4itha .Vatutmt space in between must include one or morelow..gas permeability materials that "'ridge (!fr span the yaps 'between the glass sheets so as to seal off and maintain the v.aetium. The most advantageous places.to bridge those gap6 are in the edge regionsof the glass.sheets..
EXamples in theartshow that ocanbinations ofdiffetent materialsinay be used te bridge the gaps. 'those materials may be ,configured in literally an infinite. .number Of Ways. As examples, the materials may be .entirely between the glasasheets,..or entirely outside the space between the glass sheets., or they may- be partially between the glasssheets.
iormi The commonality among the infinite number of possible embodiments for this invention is that a viscous material bridges tir spans:sortie portion of the:
gap between the glass sheets Ola VICi unit and that relative: lateral mOvement between the.
glass SII0CtS. is accommodated by the viscousmaterial undergoing viscous shear. It is contemplated that the .s.cope of this invention eneompasses.all of the infinite number of ways that a. viseous material might be configured and constrained so as to function in the above. described manner.
REFERENCES CITED: OTHER PUBLICATIONS
Jousten K, editor, Handbook of Vacuum Technology, Weinheim, Germany: Wiley-VC.H;
2008. 1002 it Le Bourhis 2008, Glass, -Mechanics and Technology., 'Weinheintõ Ciertnany:
Wiley-VC.H. 36p.

Maosko.C. W. 1994. Rheology, Principles,. kleasurememt$, and .Applications.
New York:
Wiley-VC{. 550 p, Morrison F, A. 2001, Upderstanding Rheology, New York: Oxford Unisiergity Presti', 545 P, Nipp' Sheet 200..Precaution For 1).se and Maintaimmee [sic]. 1 screen.
Availablo.lfrom: http://www.tisg-spacia.cojpitechlwarrantylitmi Onlon 20Q3, A .Or's Guide to Vacuum Technology, 20 E. Hoboken, NJ:
john Wiley- & Soils.. .l& p, Roth, A. 1994, Vacuum Sealing Techniques. Woodbury, NY An Institute of Physics. .$45 p,

Claims (16)

1. A method of assembling a vacuum insulating glass unit, the assembled vacuum insulating glass unit comprising;
(a) a first glass sheet and a second glass sheet with a vacuum space in between at a pressure less than atmospheric pressure;
(b) at least one spacer in between the first and second glass sheets configured to contribute to the separation of the first and second glass sheets and the maintenance of the vacuum space; and (c) an edge seal comprising:
(i) a cavity configured to contain a first viscous material;
(ii) a first viscous material contained in the cavity, wherein the first viscous material restricts the rate at which gas permeates into the vacuum space; the edge seal being configured to allow the first and second glass sheets to move laterally relative to one another when the first and second glass sheets experience differential thermal strain and further configured such that viscous shear occurs within at least a portion of the first viscous material when there is relative lateral movement between the first and second glass sheets;
and (iii) at least one barrier whose configuration constrains the first viscous material, the method comprising evacuating the cavity configured to contain the first viscous material to a pressure less than atmospheric pressure and, subsequently, pressuring the first viscous material into die cavity,

2. The method of claim 1, wherein the first viscous material has been degassed or outgassed prior to being pressured into the cavity.

3. The method of claim 1, wherein at least a portion of the cavity configured to contain the first viscous material is disposed between the first glass sheet and the second glass sheet.

4. A. method of assembling a vacuum insulating glass unit, the assembled vacuum insulating glass unit comprising:

(a) a first glass sheet and a second glass sheet with a vacuum space in between at a pressure less than atmospheric pressure;
(b) at least one spacer in between the first and second glass sheets configured to contribute to the separation of the first and second glass sheets and the maintenance of the vacuum space; and (c) an edge seal comprising:
(i) a cavity configured to contain a first viscous material;
(ii) a first viscous material contained in the cavity, wherein air permeates through the first viscous material and into the vacuum space. in the assembled vacuum insulating glass unit; the edge seal being configured to allow the first and second glass sheets to move laterally relative to one another when the first and second glass sheets experience differential thermal strain and further configured such that viscous shear occurs within at least a portion of the first viscous material when there is relative lateral movement between the first and second glass sheets; and (iii) at least one barrier whose configuration constrains the first viscous material, the method comprising evacuating the cavity configured to contain the first viscous material to a pressure less than atmospheric pressure and, subsequently, pressuring the first viscous material into the cavity.

5. The method of claim 4, wherein the first viscous material has been degassed or outgassed prior to- being pressured into the cavity.

6. The method of claim 4, wherein at least a portion of the cavity configured to contain the first viscous material is disposed between the first glass sheet and the second glass sheet.

7. A method of assembling a vacuum insulating glass unit that includes, the assembled vacuum insulating glass unit comprising:
(a) a first glass sheet and a second glass sheet with a vacuum space in between at a pressure less than atmospheric pressure;
(b) a plurality of polymer spacers comprising a polymer disposed in between the first and second glass sheets and configured to contribute to the separation of the first and second glass sheets and the maintenance of the vacuum space; and (c) an edge seal comprising:

(i) a viscous material, wherein the viscous material restricts the rate at which gas permeates into the vacuum space; the edge seal being configured to allow the first and second glass sheets to move laterally relative to one another when the first and second.
glass sheets experience differential thermal strain and thriller configured such that viscous shear occurs within at least a portion of the viscous material when there is relative lateral movement between the first and second glass sheets; and (ii) at least one barrier whose configuration constrains the viscous material, the method comprising placing a plurality of spacers on the first glass sheet and subsequently placing the second glass sheet on the plurality of spacers, such that the plurality of spacers are positioned in between the first glass sheet and the second glass sheet in a configuration that contributes to the separation of the first and second glass sheets and the maintenance of the vacuum space; wherein prior to being placed between the first glass sheet-and the second glass sheet, at least a subset of the polymer spacers are interconnected.

8. The method of claim 7, further comprising removing some or all of the interconnections between the polymer spacers prior to placing the plurality of spacers on the first glass sheet.

9. The method of claim 7, further comprising removing some or all of the interconnections between the polymer spacers after placing the plurality of spacers on the first glass sheet.

10. The method of claim 7, wherein some or all of the plurality of polymer spacers remain interconnected within the assembled vacuum insulating glass unit.

11. The method of claim 7, wherein at least a subset of the polymer spacers that are interconnected prior to being disposed between the first glass sheet and the second glass sheet have the same array prior to being disposed between the first glass sheet and the second glass as they have in the assembled vacuum insulating glass unit.

12. The method of claim 7, wherein the subset of the polymer spacers that are interconnected prior to being placed between the first glass sheet and the second glass sheet comprises at least 100 polymer spacers.

13. A vacuum insulating glass (VIG) unit comprising:

(a) a first glass sheet and a second glass sheet with a vacuum space in between at a pressure less than atmospheric pressure;
(b) at least one spacer in between the first and second glass sheets configured to contribute to the separation of the first and second glass sheets and the maintenance of the vacuum space; and (c) an edge seal comprising:
(i) a degassed or outgassed viscous material, wherein the degassed or outgassed viscous material restricts the rate at which gas permeates into the vacuum space and; the edge seal being configured to allow the first and second glass sheets to move laterally relative to one another when the first and second glass sheets experience differential thermal strain and further configured such that viscous shear occurs within at least a portion of the viscous material when there is relative lateral movement between the first and second glass sheets; and (ii) at least one barrier whose configuration constrains the viscous material.

14. A method of assembling a vacuum insulating glass unit, the assembled vacuum insulating glass unit comprising:
a first glass sheet and a second glass sheet with a vacuum space in between at a pressure less than atmospheric pressure;
a plurality of polymer spacers disposed in between the first and second glass sheets and configured to contribute to the separation of the first and second glass sheets and the maintenance of the vacuum space;
and an edge seal that seals the vacuum space and maintains the vacuum, the method comprising placing polymer pre-arrayed spacers on the first glass sheet and subsequently placing the second glass sheet in contact with the spacers.

15. The method of claim 14, further comprising removing at least some of the polymer interconnections between the spacers of the polymer pre-arrayed spacers prior to placing the second glass sheet in contact with the spacers.

16. The method of claim 14, further comprising removing at least some of the polymer interconnections between the spacers of the polymer pre-arrayed spacers after placing the second glass sheet in contact with the spacers,