CA1250727A - Use of fibrous mat-faced gypsum board in exterior finishing sytems for buildings and shaft wall assemblies - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

An exterior finishing system for a building, including particularly an exterior insulation system, which includes a fibrous mat-faced gypsum board, preferably a board in which the set gypsum core thereof is water resistant, and preferably one in which the set gypsum core is sandwiched between two sheet of porous glass mat, with the outer sur-face of at least one of said mats being substantially free of set gypsum, and means for preparing and board, including control of the viscosity of the aqueous gypsum slurry from which the set gypsum core of the board is formed. Also, the use of fibrous mat-faced gypsum board as the shaft liner panel in a shaft wall assembly.

Description

USE OF r~ ous M~ E~ r~5l1M i~OA1~D ~N E~'l'E1~IOR
EINIS11Ir1G SYS'i'_~lS EO1( 1~U~ VrN(,~ ~ND S11 l' W~Ll _SS MBLIES

l~'ielcl Or L1~c~ r1lve~ on Thls invention relates to improve11\el1ts in exterior Einis11inc1 systems sueh as, for example, exterior insulation sys-Lems for ~uiltlin(Js, anc1 a]so to lmprove111e1lts in s11at waLl assen1blies Eor builclings. More partieulctrly, tllis invenLio1l relates to an improvec1 struetural eomponent Eor use as a su~port SULEace :lal an exter:i()r Ein:isllillcl system, illcluclill9 an cY~terior insulation syste111 (someti111es reEerred to herei1l Eor eonve1lienee as "EISyste111). In adclil:io1l, tl1e present inve1ltio1l eneo1npasses i~nprove111e1lts in hollow sl1at wall assemblies, ~or c~xa1nplc, those used i11 COnStrUCtinCJ elevatc)r sllafts and stairwells.

'1'11is inventio1l will be deseribecJ initially in eon1leeLion wit11 iLs use in EISyste111s, but, a, will be ex-L~lainec] 11erc!inclLter~ its use ~1as wider applieability.

EISyste111s a[e presenLly being used n1ore antl n~oce widely to insulate exisLing bl1ildings antl ~uiltlint~s uncler eon5truetic)n ineludi1lcJ inc]ostrial, eommertial, n1unieipal, insLituLional, an-1 reside1ltl;ll ~uildincJs. ~nciLallation of a typieal E:ISysLe111 -in new eonstluetio:l cJe1lerally involves the rollowinc1 setluential s1:t!ps: (~) eonstrueti1lg a frame Eor suppoLt ot t11e ouLside waLl oE a buildi1lc1; (B) afixin(!
to t1le rran~e s1:rucluLal pa1-1-~ls to pro~ide a sn~oot11 eonLi;luol1s surEaee for L1~e suL~L~ort o oL1~er of ~he eon1l)one11~:s oE tlle EISystem; (C) ai[ixi11g ~o t11e su1-port sc1rraee panels o i115U-la~:ioll;

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and (~) afEixing to the panels oE insulation a mesh-like material whiell in turn is eovered ~ith an exterior finish-ing matcl-icll havinc~ weatherinc3 and aesthetie properties.
Sueh systems are desic3ned to be not only hishly insulative in eharaeter and attraetive in appearanee, but also weatlle~r resistant. XlSystelns ean be uscd to aclvantage to eonserve energy used 3or heclting allcl to eonserve el:ergy used Eor air-eonditionillg.

~ISysLems have inherent advantages over interior insukltillg ~systems and, in addition, they ean be used to ~etter aclvant;lge than interior insulating systems in many applieations.

E'or examp1e, the range of temperature variation in structural eomponents eomprisirlg the walls oE a building insulated Erom the outside is less than that for sueh eom-,LIonentS in a builcling whieh is insulated from the inside.

Aeeorclingly, sueh struetural eonoonents when insulateL3 from the outside are subjeeted to signic'ieantly lower amounts oL stres~s eaused by thermal e:<pansion and eontraetion than those insul;l~ecl from the inside. This is particularly ac1van~ayeous in applieations wllere the struetural eomponents comt)risc- materi.lls hilvincJ mar'~edly diE'c'erent eoeEfieients oE e~ ;lncioli, as is cEten tile ease. In ac'dition, the in-tCIi~>! spaee in a buildi;-lg having an EISystem tends to havL
.1 ~ ,ilc~ el~ L~r~tllLe an~3 ~ c c~ ; t;larl t!lat ~ q ~ t~ Lr(~l~ ti~ i ci 2 .

~2~3~;27 Certairl buildings are not capable of being insulated frorn the interior except that valuable inside space is lost to the system. The installation of an ElSystem does not disturb the inside space of the building~

~n EISystern can be used also to modernize or other-wise renovate the exterior of a building in need of renovation.
Various of the EISystems which are commercially available yive the architect a wide range oE aesthetically pleasing designs from which to choose. In addition, the cost of installing an EISystem is relatively low when there is taken into account both the costs of other systems and the improved thermal efficiencies that can be realized. The relatively l;ght weight of both the insulation and the exterior finish in an EISystem is particularly advantageous in new construction because of reduced Eoundation requirements.

Thcre are, I)owever, problems associated with the design and/or installation of EISystems. ~s will be dis-cussed in detail below, various of the problems stem from the type of material which is used as the supporting member for the insulating and exterior finishing materials of the system. The present inventioll involves irnpr,ovements in such supporting member.

~zS~7z7 _ported Developments ~ s mentioned above, a typical EISystem ineludes a supporting melllber to whieh there is aEEixed insulating material, which in turn is covered with an exterior finish-ing material. ~n eY~ernplary EISystem includes a wood or metalframe which is mechanically held in place by nails or scret~s to appropriate structural membel-s of the building, with panels of the supportinq member in turn mechanically affixed by nails or serews to the frame. The supporting member, whieh typieally consists of a smooth continuous surEace comprising individual panels of material positioned in abutting relationship, must be stroncJ enough to carry the weic;ht of the components which overlie it, includin~ the insulatin~J and exterior finishinq materials. ~lthougll low density, light wei~ht insulating panels oE expanded polystyrene are used widely in such systems, the exterior finishing mLtterial is cJenerally a much denser and heavier t,/eight material, for exanlple, an acrylie resin/eement eoating that may inelude deeorative agc~regate embedded therein.

Certaill oE the eommereiali~ed EISystems inelude the use OT' panels of a Portland cemerlt--based eomposition as the structural mermber for the support of the overlyin~J

~>anels of insulatioll and exterior Finislling material. It ~z~

is believed that such cement-based panels are described in U.S. ~atent No. 3,284,9~0 which discloses a building panel comprising a core consisting of a mixture oE hydraulic cement and light-weigllt aggregate (for example, perlite) sandwiclled between sheets of Eibrous material (for example, woven glass fiber screen), which are adhered to the faees of tlle core by separate layers of bonding material contain-ing at least 50% hydraulic eement. ~lthough the cores of such panels include a light-weight aggregate, the panels are nevertheless relatively heavy. For example, a panel 3 ' X 4 ' and 7/16 " in thickness weighs about 40 1/2pounds. The handling and installation of such panels lead to the consurnption of relatively large amounts of energy. This is a burden to workmen and makes transportation of the panels relative]y costly.

~ rmaterial whicll is used more widely in EISystems than the aforemetltioned cement board is gypsum board, that is, panels comprising a core of set gypsum (calcium sulfate dihydrate) sandwiched between paper cover sheets. The part-icular type oE gypsum boarcl that is recommendecl for usein EI$ystems is known as "gypsum sheatllillg" which is sypsum board desi~;ned for use on the e~terior of builclings where it serves as all unclerlyilltl surface wllicll is covered with such materials as alllminum, woocl sidillt~, Por~lancl cemell~ stucco alltl, in thc cane o~ an EISysteln, with insulating an(l exterior finishing materlals. Conventiollcl gypsum sheatiling, as opposed to conventional gypsun wallboard for use in the ~25~7Z'7 interior oE a L~u.iklillg .;nelu~les a ~set CJypsull~ col~o wlliel contains one or mc>re a(1clil:.ives wlli.ell impLove l.lle water resisLanee oE ~lle set eol-e. I`IIe ~ sum core Or eo~ eJeially avai.la~Le wal.LL)c~al-cl ca~ s~ mue:ll as 40-50 wt.~i water when in~ ersecl Lllereill aL a l:e~ r~a~ e oE 701; Eor aL~out 2 llours.
~s Llle al~sorpt.i.oll oF Wnt(?l' L~`lltlS. Lo suL)stallL.ial.ly recluee tlle sLreng~ll oE lle eore, mlLel.i.lls wlliell reeluee Llle tencleney oE
Lllc eore to aL~soll) walel al-e .ialeLu~ecl there.ill. ln a~lelitic)ll, slleatlling llas waLel-rel-e.ll.allL paL)er eover slleeEs wlliell slle-l w.lLor Illis .is Le~n~lJc~l~lly proteeLioll Eor Llle slleatl~illcJ L~e[ore it is inst:allecl anel IJe[o:re :it i5 eoverecl w.itll the exterior r.i~,.i 511.illCI IllaL(~l-icll.

Gypsum sl~oa~ llas In.ll-y ~les.iraL~:le ellalaeLor.isLk s wllielllllake iL sui~aL~:Le rOr use .in an ~ISystem. For eY.Ill~ple~
15 SUCIl slleatllill~l llilS relaLivc.l.y cJcw.l ire-res.i-;Lanl: pr~)L~rrLies, it .is re:Lat.ive:Ly l.i~lllL .in we.icll~l:, it has salisl`aclory water-res.i!:tallL propeL~ier; all(l il: C.lll L,e Illeellallie.llly a~rixe(l in collvellielll: rasllion l.o a ll(el.al or wooclell rr.lll~e wl~iel~ unelerLic!ci the slleatllilleJ.

NotwiLl~iLall~lill.l Llle aCo.L-elllel-ltiolle(l, ec~lleelns llave I~CC'Il e.YL~reSSC~L resl~CCLill~J ~l~c Ll'iC oE suell clyps~ln~ sllea~l~i.rlcJ .in l.L':y~e-ll~.. I~y \~;ly ~C L~ llo~lll(l, iL is 110~?~ iL is eoll-vouti.ollal .i.n llle .inclu~ Lo arE.iY. panels oC illsu.Latillg nlater.ial Lo Llle uncle) lyincJ suL-i)ol-L oE (Jyl~SUm slle~lLIl.il~ Jy Llle use oL an 25 a~llleS.iVe C~ :CI: ia.l all~l, ill lall'll, to aCE.i.x L~y tlle use o[ aell~esive ol-iil~s ~ cl~ ~,r 1l~ . w~ over:lie ~ lle1s oF i~ u-l~Li~ x(~ )L r~ I(c~ .,[ Il(e~llallic~L rd5L~ 9 ~ 5 in tl~e eons-rueti-)ll oE tl~e rrilllle Or tlle L~uikl.irl~l allcl in a~rixin-~ZSI~2~

the gypsum sheathing to the frame, all of the components of the EISystem are in effect glued together.

Tests designed to cvaluate the cohesive strength ol and the adl)esive strenyth, bet~een the vari~us components comprising the F.ISystem have shown that initial failure (pullirlg apart) of h' systern occurs not in any of the adhesive laycrs, but in the paper cover sheet o~ the gypsum sheathing. Such cover sllect consists of multi-ply paper, for example, as many as 7 layers of paper adhered together in a form that appears to the eye to be a mono-lithic sheet oL paper. AccordingLy, thc cohesive strength of the paper can be characterized as the weak portion of the system.

~nother concern respecting the use oE gypsum slleatllil-(J in ~ISy:terns o~ the aforemclltionec1 type is that water leakage through the systenm can lead to the deterior-ation of the bond betweell the paper cover sheet and the gypsum core. (Although the system is designed to be water-prooE, there are circumstances where defects in one or more plies of the systcm and/or unusually severe environmental conditiolls are the cause of water s~eepage.1 It should be apprcciated that deterioration of this bond can lead to cracking c~ th~ exterior Linish, and possibli even collapse oc po~tions oL the system as the compollent wllich is adhered to the pclper cover sl)eet pulls apart.

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In an eEfort to overcome the aforementioned type problems, it has been proposed to affix the insulating matar-ial to tha undarlying gypsum shaathing by the use of mechanical fasteners which extend througll the insulatinq matcrial,the core of the gypsum sheathincJ,clnd into the frame. This approach to the problem has tlle disadvantacJc that the work time involved in installincJ the system is increased significantly inasmuch as it is much more tima consuminq to install fasteners than to apply an adhesive. ~nother shortcoming oE the fastener approach is that the fasteners provlde paths for the flow of water which may penetrate the system and weaken the bond between the paper cover sheet and qypsum core, as mentiolled above.

Irrespective of how the insulatinc3 rnaterial is aEfixed to the underlyincJ qyps~m sheatllincl, there is another ]s problem connected witll the use of shaathinq in EISystems.
i~ecause oE its susceptibility to declradation by water, care rnust be taken to protect the sheatlling from rain and other moisture conditions which may be encountered as the sheathinq is stored at the job site awaitinq use and durincJ installation.
~ra~ing sucll protective precautions consumes time, causes incon-vallicllce, and sometimes causes delays in installation oE the systcm - all of whicll tend to increase costs.

~ lthoug}l gypsum shcatlling has a water-repellant paper surEclce wllicll provides some limited protectioll aqainst watcr de~3radatio~l, this ~}~e oE surfacc forllls a ralatively pOOI l~an~1 Wi.til ~aLe~-based adhesivcs WhiCIl are usecl to aclhere to the surface ol~hc`l comi>c-nenls of ~he l.ISystc;n.

~ZS~7;~

The present invention is directed to use in EISystems of a support member eomprisinc~ an improved cJypsum-based struetural eompollent which is modified in a manner sueh that problems oE tlle type associated with the use oE eonventional c3ypsum sheathincJ are either overcome or alleviated signiEieantly.

SUM~Y OF T~IE tNV~NTION

In accordance with the present invention, there is provided an improved structural support element comprisinc~ a fibrous mat-Eaced ~ypsum support surEace Eor use in an exterior Einishing system, includinc~ exterior insulatincJ systems, for buildings. One embocliment of the prescllt invention comnrises an exterior insulation system Eor a bu;ldincJ whieh ineludes a Eibrous mat-faced gypsum support surEace Eacing away from said buildincJ, lnsulatincJ material having an inner surEace and an outer surEace, tlle inner surEace oE which is adhered to said support surEace by an adhesive material, the insulating material being substantially free of channels penetratincJ therethroucJh and between said inner and outer surEaces, and exterior finishing material overlying the outer surface oE said insulating ma-terial.
The preEerred form oE Eibrous mat Eor use in tlle present invention is a glass fiber mat in which Eilaments of glass fiber are bonded together by an adllesive.

Preferably, the fibrous mat-E;Ieed gypsum support surface eomprises a gypsum eore having one or more additives therein wlliell improve the water resistance oE the core. ~s will be seen ~L2~7Z7 from examples reported below, a struetural member eomprising a water-resistant gypsum core faeed with glass mat, whieh itseif is hydrophobic, has outstanding weathering characteristics.

~n aciditional preferrecl form of the present invention comprises a cJypsurn board havinc~ each of its core faees eovered with a porous glass fiber mat, with the mat of one of the Eaees beincJ adhered to the core by set cJypsum penetrating but part--~ay into the thiekness of the mat and havincJ its outer surfaee sub-stantially free of set gypsum. ~s will be deseribed below, the qlass Eiber mat surfaee, whieh is Eree of set gypsum, provides an exeellent substrate to whieh overlying panels of insulation ean be aclhered.

In one embodiment of the above form of the invention, the outer surface of the mat of the other core faee is also substantially free of set clypsurn, witll set gypsum of the eore penetratincl but part-way into the thiekness of the mat. As will be described below, there are manufacturing advanta~es which aceompany the produetion oE gypsum board of such embodiment.

In another embodiment of the aforementioned form oE
thc present invention, the set c~ypsum of the eore penetrates substantially through the thiekness oE the mat oE the other eore faee over substantial area portions thereof in amounts whieh are sufficient ~o coat glass fibers of the mat with a thin film of set gypsulll, but not suEEicient to form a smooth, continuous coating Of set clypsum. This emhc>climent in whicll siclnificant por-~lO-~25~

tions oE the outer surface of the mat have set gypsum thereon provides a protective surEace in a two-board packacJe in which the boards are packed together with the gypsum-free surfaees in face-to-face relationship and Witll the gypsum-covered faces beinc3 exposed. More particularly, this preferred form of board comprises a set cJypsum core sandwic}led bet~een two adhering sheets of porcJus cJlass mat o preclctermined thickness, eaeh of said mats havincl an inner ancl outer surface and comprlsincJ
randomly distributed glass fibers bonded by an adhesive material, the inner surface oE each of said mats being adhered to said gypsum core, and with set gypsum of the cGre at one surface thereof penetrating substantially through the thickness of one of said mats over substantial area portions thereof and coating sul?stantial area portions of the outer surface thereof and with set c~ypsum of the core at the other surEacc thcreof penetratinc3 but part-way into the thickness oE the other of said mats, the outer surface of the other of said mats bcing substantially free of sec gypsum.

Still another aspect of the present invention comprises a process for making the aforementioned embodiments of gypsum board, that is, the embodiment in which both outer surfaces of the mats are substantially free of set gypsum and the embodiment in wilich the outer surface oc one of the mats is s~lbstantially Eree of set gypsum and that oE the other mat has set cJypsum thereon.
'l11E~ process includes knowll steps used heretofore in manufacturing in COIltillUOUS fnsllioll conventiollal wallboarcl and known glass-~ii?el` ma~:-racecl gypsum boarcl, but dif~ers therefrom in thnt the v iE~cosi ~ y ~,r t~ a~l~lc~o~ls C3ypE~ l sl ~Irl-y rron~ cll thc! hoc~rcl cor~

. 1 ~_ ~Z5~7;~

i9 made is eontrolled in a manner sueh that the slurry pene-trates into the mats to the e:~tent needed to aehieve the desired result. The basie steps of the proeess eomprise:

~) EormincJ an aqueous slurry of ealeined gypsum;
S (B) eontinuously feedincJ said aqueous slurry onto an underlyincJ, moving and supported porous fiber glass mat havillg a predetermined thiekness and an outer surfaee;
(C) formincJ said deposited slurry as it is carried on said moving mat into a panel-like shape; and (D) applyincJ to the top surfaee of said panel-like shape oE slurry an overlyinc3 porous fiber cJlass mat of prede-termined thickness.

In forming gypsum board in whieh both of the outer mat surEaees are substantially gyæsum-free, the viseosity of the slurry is maintained at a value suell that portions oE said slurry penetrate but part-way through the thiekness oE eaeh of said underlyincJ and overlying mats and the panel-like shape oE
slurry is maintained as the ealeine(l clypsum sets to .Eorm a set gypsum eore having adhered to its surEaees the underlying and overlying fi.ber cJlass mats.

In formincJ the gypsum-eoated/cJypsum-Eree form of glass Eiber-faced board, the viseosity of the slurry is maintained at a value sueh that porLions of said s]alrry penetrate substantially throucJIl the thiekness oE saicl underlyillcJ mat over substantial arc~-l pol-~ions ~helec)f to coat substalltinl aren portions of the outel- surracc? nll(i nt a value sucll thnt portic,lls Or said slurry - - `

~Z5~727 penetrate but part-way into the thiekness of said overlying mat.

There are numerous advantages which flow from the use of the present invention. ~n i~ISystem whieh ineludes a ibrous mat-faced cJypsum support surfaee that has affixed thereto insulating material by adhesive only, that is, witho~t fasteninc~ means whieh extend throucJIl the insulating material, has hicJher tensile or eohesive strencJth than a like system whieh ineludes eonventional paper-faeed gypsum board. Testing of systems of this invention whieh inelude insulation in the form of expanded polystyrene panels has shown that initial failure :is experienced by a pu]ling apart of the expanded polystyrene panel, thus evidencing improvement in strencJtll relative to con-ventional systems where initial failure is experieneed in the paper plies of the gypsum support member. The fibrous mat-faeed surfaee of the qypsum support member is water resistant in contrast to convelltional paper cover sheets of gypsum board whieh can soak up water. This improved water resistance gives the applieator greater flexibility in seleeting adhesives tllat ean be used to adhere insulation directlv to the mat-faeed surfaee of the gypsum support element as adverse afects are not encountered by the use of water-based adhesi~es. The ibrous mat-faced sur-face oE the gypsum support element is "nailable", and accorclinc~ly, it ean be securecl readily to an ullclerlyillg Erame or other substrate by nailincJ. In comparisoll to various oE the eommereially available systems, the improved support surfaee oE the present invention has improved rigiclity and strengtil uniFormiLy in both the lengtll and ~zs~

width dimensions of the system. Unli~e eonventional paper eover sheets the fibrous mat does not expand or eontraet durincJ the manufaeture of the produet; this reduees eoekle and leads to uniEormity of dimensions. The preEerred embodi-ment oE the invention whieh ineludes the use of a water-resistant eore provides a substantially ir~proved weather-resistant produet whiell better resists cle-~radation both within and outside of the system.

BRIEF DESCRIPTION OF T~IE DR~WINGS

FicJure 1 is a somewnat diac3rammatie frac~mentary side elevationll view illustratillcl por~ions oE a mallufaeturinc~ line for produein~ cJypsum board of a type suitable Eor use in the manuEaeture of cJypSum board prepared for use in aeeordanee with the present invention;

Fi~ure 2 is an enlarged EracJmentary seetional view taken as indiealed toward the le~t of Ficlure 1 oE an underlyinc~
fiber glass mat used in the manufaeture oE the cJypsum board;

Ficlure 3 is a frac;mentary plall view ta~en as indieated by the line 3-3 on Ficlure 2;

Fic1ure 4 is an enlarqed seetional vie~ taken as indi-eated toward the right on Figure 1 ancl illustratiilg both under-lyincJ and oveLlyillcl fiber ql.lss mlts ~ h inlervenincJ gypsum eomposition usecl in the nanuEaeture oE the board;

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Figure 5 is a fracJmentary plan view taken as indicated by line 5-5 on Fiyure 4;

Figure 6 is a fracJmcntary bottom view taken as indi-caLed by the line 6-6 on E`igure 4 and illustrating the bottom surface of the underlyincJ mat oE thc board;

FicJure 7 is a transverse sectional vie-~ of an edge portion of the completed board, this view bcinc3 taken as indi-cated by the line 7-7 on Fiyure 4;

FicJure 8 is a Eurther enlarcJed fragmentary sectional view takcl~ as indicated to~ard the top oE F'iq-lre 4;

Figure 9 is a Eurther enlarcJed frac~mentary sectional view taken as indicated toward the bottom of FicJure 4;

Fiqure 10 is a view illustratincJ two complete gypsum boarcls fabricated accorclincJ to the present invention and beiny assembled for packacJillcl, with the top Eibrous mats oE the two boarcds prescnted toward each other;

Fiqure 11 is a view of tn~o boards assembled in the manner indicated in Figure 10 and bound toclether for purposes of shippincl;

lic1ure L2 isa some~ at dia~JIammatic vertical sectional vie~ throu~h Lhe uL)per portion oF an e~terllal buildincJ wall, as insula~ed in accordallce witll the present invention: and ~1~5~ 7 FicJure 13 is an enlarged vertical sectional view taken substantially as indicated on FicJure 12.

DETAII.ED DESCRIPTION OF TIIE IN~ENTION

The essential components of an EISystem eomprise lnsulating material W}liCil is sandwic}lc!d between an underlying support surface and an exterior finishincJ material wtlich can be an integral part oE the i.nsulating material, but whieh is usually applied to the insulating material at the site oE
installation. From one EISystem to the ne.~t, there exist variations in structural details and components. For example, althougIl tlle exterior Einislling material may be afEixed directly to the insulatincJ material, various systems include a reinforeillg component sandwiched between the exter.ior finishincJ
material and the insulating material. The reinforeing compo-nerlt comprises cJenerally one or more plies of fiber glassreinEorcincJ fabric or mesh which is aclhered by suitable mastic to the surface oE the insulatinci material. In some systems, the support surEace is aEfixecl to a wocden frame attached to the exterior surface oE the outside wall of a building, whereas in other systems a metal rame is used. In certain applieatlons, the support surEclee may be aEfi~ed directly to the exterior surface oE an outsicle wall, for example, one eomprising einder bloe~s or eoncrete bloc~s. In new construction, the support surface is typiealiy a~Ei~eci clireetly to the frame of the buildinq.

'l~h~ adhesive C>l' mastic Ec~r adherillg toge~her compon~nts of the system tencls to vary from one system to the ne~:t, and typically -lG

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comprises specially formulated proprietary compositions. The improved support surEace oE the present invention can be used satisfactorily and to good advantacJe in EISystems whieh include overlying plies of insulating and exterior finishing materials, and other optional components.

Presently, the most populal^ly usecl insulatincl matcrial in EISystems is expanded or Eoamed polvstyrelle, a material which has good moisture resistant properties. ~lthough it has desir-ably low water vapor transmission, it is not a vapor barrier, but instead is capable of breathing. Rigid panels oE expanded polystyrene are used most wiclely in EISystenns. Sueh panels have satisfactory compressive strength and resilience and are presently available in thicknesses ranging from 1/2 to 6 inches, widths Erom 6 to 48 inclles and lenc~tlls ranc~inc~ Erom 4 feet to 16 fect.
One commercially ~vaiable system utilizes rigid, e~panded poly-styrene panels whicll are 2' X 4' X 1".

Otller thermal insulatincJ materials can be used in EISystems also. E~amples oE such materials include extruded polystyrene, polyurethane, isocyanurate, cement-based insulating plasters, ancl phellolic foam. Insulating materials generally have low thermal conducting and low density.

As mclltiolled above, various EISystems include a rein-Eorcillg componellt, Eor e~ample, in cloth form, sandwiched between the insulatillg mElteriE~l and the e~terior finisllincl material. Glass 25 cLotll is most wi<lc!ly used at thc present time to reinforce th(~
system, that 1.:, ~o improve thc impact strength of the system.
The part-;cular type or types o~ C!lass ClOtil uscd ancl the number o pl.ic.s thc 1(:0[ WlliCIl EirC UsC(l dt pel-d on th(` i `.IpaCt rC?s.i.stallce which ~2~ 7 is clesirecl. i,xalllp:Les oE reinEorc.illg eloth or Eabrie wllieh ean bc uscd in the sycitelll are woven cJlass, (llass Eiber skrim and cJlass Eibor mesll. :Lnstcll]aLioll oE Lhe reirlrorei.ncJ Eabrie c~ene-rall.y invo]vrs applyi.ng a su;~uble a(illesive to the surEaee o~
Lhe insu.l.atin~l mateli.cll and tllen appl~in~l the Eabrie thereto.

~dditioncll plies oE Eabr.i.e eall he appliecl i r des.ired. ~ eement/
aerylie resin is an e.vamp.le oE an adheslve that ean be used.

The ex-eriol. rinisllillcJ maLel-ial eatl be aE[ixed direetly to the insu:kltin(llll,l~-erial or l:c~ an in~erme(liclLe surEaee SUCIl as, for examp1e, the surFace oE a reinEorein~J melllber as deseribed above. The exterlor Einisl~inc)lll.lte)i.ll has weatllc~rillg eharac-teristies alld is preEerclbly appeali.ll(l im apyealilnee. PresenLly, tlle most widely used exterior ~inish is an aerylie resin-based eomposit:ion whiell is avai.1abJe i.n a paste-type Eorm wlliell is syread or trowe1ed on Llle unclerlyillc~ suLsLrate. One type oE suel compos:iLioll ean be deseribecl al: a reacly~lllixed synthetie resin plasLer. ~Eter applieaLioll, the resin seLs to ~orm a tou(Jh, weather-resistallt soli.d material whiell aclheres ticlhtly to tlle underly.ill~J substrnte. Sueh resill eompositions are available eonunereial]y in a var;.ely of eo:Lors. 'l`hey inelude optionallï
aclcJrc(JatC ~rhicll can v~nl.y ill sizc~. Tl~i9 allows the apl)licator to ehoose a pal-t.ic:ular eomposi.~ic)n wlli.ell yellllits llim to upply a Einisll that eall vary in te~t~lre Erom Eine to eoarse. Finislles wh:iell have a stueeo-li~e appealallee al-e popular. Small stones oE
various eolc)rl; cnlll bc eml)ccldc~d .i.ll tllC eomposit.ioll ror cleeor~tive O ~; C S .

~2S~)72~

Examples of other material3 that ean be used as an exterior finisll are Port]and cement stucco including for example sand and larger acJcJreCJate.

The exterior Einish ean vary in thiekness over a wide rancJe with a thiekness oE about 1/16 to about 1/4 be:ing e~emplary.

TurnincJ now to a deseription of the im2roved support rnember for use in exterior ss~stems oE the present invention it eomprises a set qypsum eore faeed with a .ibrous mat. Thc cJypsunl core is basically oE the type used in those gypsum structural produets whieh are ~nown as gypsum wallboard drv wall cJypsum board and gypsum sheathing. The eore of such a product is Eormed by mix;.ncJ wclter with powderecl anhydrous caleium sulEclte or ea:Leium sulfate hemihydrate (CaS04 1/21120) also known as calcined gypsum; and thereafter allowing the mixture to hydrate or se-t into caleium sulfate c7~ihydrate (CaSOI-2ll20) a relatively hard material. The core of the support member wi.:LI. in cJeneral eomprise at least about 85 wt.
percent of set gypsum.

7Z~

Tlle eompositlon from t~hieh the set cJypsunn eore is made ean inelude optional eonstituents, includincJ, for example, those included eonvcntiollally in cj~psum sheathillg. Examples of sueh constituents include set aeeelerators, Eoamin~l a~.3ents, and S clispersincJ acJents~ ~s will be deseribed in more detail belo~, a preferred clypsul~ eore Eor use in the present invention ineludes one or more additives whieh im?rove the water resistant ?roper-ties o tne eore.

The surEaee oE the eore to whie}l the insulatinc3 material oE the system is a.~Ei~ed is Eaeed with a Eibrous mat. The fibrous mat should be suffieielltly porous to permit ~ater in the aqueo~ls ~ypsum slurry from whieh the cJypsum eore is made to evapor.lte theretllrough. As deseribed in detail below, the CJypSUm support elemellt for use in the present invention ean be made lS erfieiently by forminc3.an aqueous ~ypsum slurry whie}l eontains e~eer.s water ancl plaeincJ thereon the fibrous mat. ~ided by heaLin.~, e~eess water evapol:ates throur~3h the porous mat as the caleined c1ypsum sets.

The Eibrous mat eomprises material t~hieh is eapable of EormillcJ a stroncJ bond ~ith t.he set qypsum eom?riSinc~ the eore oF the support sulEaee. E.Yamples oE sueh Tlaterials inelude a mineral-type ma-tel-i.al sueh as cJlass Eibers and synthetie resin Eiber~. The mat ean eomprise continuous or diserete strallds or ibel-s alld L>e ~oven c-r non~oven in form. Non~ovell mats sueh as ehc~rped strancl ma~: and ec)ntilluous strand l~at CUIl be used satis-E;lcLvrily all(l are :less eo~tl} than l~ovelllllatel-inls. The strands 0, .C;!C')l mats are bondecl ~:ocJeLIler b~ suitab].e adllesive. ~rhe mat '7 cal1 range in th;ckncsri, for e~campLe, from about 15 to about ~!10 mi1s, wi!:h a Lhickrlc!ss oE about 25 to aboui: 35 mils bein~J
preEerrcd. '~ e aEorclnentioned fibrous n~ats are known and are comlllcl-cialIy avai:Lilb]c!:in nlally Eorms.

S 'I'i~e prefcrrc!~1 fil~rour. mat is a Eil~er c~lass mat corr~-E~risinrl Eiber cJ1ass fi1anlcnts orientcd in randolll pattern and Loulld tc,~;cLIIer with a re:;in binder. ribcr glass mats oi this tyi?c arc comrnercially available, for e:~:arnl?le, those sold undcr thc tradclnarlc I~UI~-GI,I~SS by ~lanvillc BuildincJ ~laterials Corporatiorl arld tlloc;e sold by ElK Corporation as 13UR or sllin~l1e mat .

~lthou~JIl ilnpLOVelllCntS in an EISystern can be rcalized by the use or a cJyE)sulll core wllicll has but one of its surfacc ~accc1 witll Eibrous mai: as clcsc-ribed llercin, it ;s preEcrrcd Lllat boLI~ sulracr-s oE iI1c COI'C be iaced witl1 substal1Lia1ly the salnc f ibrous mc-Leria] . lE tl;e sur-rclcc?s oE tllC core are facecl witll maleri.l1s ti1at hclve differel1t coecfic:;ents oE
c~pansiol1, tl~c core i cnds to warp. Fibrous mai -accd c~psun~
Loarcl anc1 metllocls E(7r Inaiiillcl tl~c sa~e are );nown, Eor e:~alllple, as c1cscribe-1 in Cal1adian l'atent ~;o 993,77rJ and U.S. PatcnL
No. 3,993,~322.

l\s mcnLiolle;1 above~ li1c i rcicl-rec1 Eol-m oE thc Eibr(7ur.
L- r~c~l c)~ l~s~ l cj~ t ~ co~ r i s~s ~I cl,~l7~ ll core Wll icl1 b.ls \.atcr-rcsiC;~:allt prC)l)crt;.cS. 'l'llt` p~ i'cl-rc(l Ille;lllci for impart-3L~S~)~Z7 incJ water-resistant properttes to the cJypsum eore is to inelude in the clyp~sum eompositlon From wh.Leh the eore is made one or more add:Lt:ives wh.Leh improve the abi.lity of the set yypsum eompo-siti.on to rosist be:LncJ decJradecl by wator, for example, to resist di.ssolution. In prefe]rod form, the water resistanee of the eore is sueh that it absorbs less than 5 poreent water when tested in aeeorclarlee with ~91rM method C-473 w.Ltll only the edyes exposcd.

1~he fibrous mat for use in the presellt invention has substant.ially better water-resistant properties than the eonven-tional paper faeing oE ~Jypsum wallboard or sheathiny. Neverthe--less, evaluat:ions have shown that the bond between the fibrous mat and yypsunl eore ean deteriorate relntively quiekly under the inEluenee oE water. For exEImple~ samples expc)sed to the weatller showecl loosening at the ylass fiber EaeincJ within one to two months. In eontrast, evaluations of water-resistant gypsum core faeed wlth Eibrous mat in accordance with the present invention have shown the boncl between the mat and core res:;sts beincJ degraded by water for indeEini.te periods of ti.mo.

~xamples of materials which have been reported as being effective .Eor improVincJ the water-resistant properties of gypsum products are the fo].:Lowiny: poly(vinyl alcohol), with or without a minor amount oE pol.y(vinyl acetate); metallic resinates; wax or a.sphalt or. mi.xtures thereof; a m.ixture oE wax and/or asphalt and also cornf].ower and potassium permanganat~e; water insoluble ther-moplEIst.ic oryani.c materials such as petroleum and natural asphalt,coal tar, and thermoplastic sylltlletic res.ins such as E~oly(vinyl ~L25072'-~

acetate), poly(vinyl chloride) and a copolymer of vinyl acetate and vinyl chloride and acrylic resins; a mixture of metal rosin soap, a water soluble alkaline earth metal salt, and residual fuel oil; a mixture of petroleum wax in the form of an emulsion ancl either residual fuel oil, pine tar or coal tar; a mixture comurising residual fuel oil and rosin; aromatic isocyanates and diisocyanates; organohydrogenpolysiloxanes; a wax-asphalt emul-sion wi~h or Witllout SUCll materials as potassium sulfate, al~ali ancl alkaline earth aluminates, and Portland cement; a wax-asphalt emulsion prepared by adding to a blend oE molten wax and asphalt an oil-soluble, water-dispersible emulsifying agent, and admixing the aforementioned with a solution of casein which contains, as a dispersing ayent, an alkali sulfonate of a polyarylmethylene condensation product.

lS A preferred material for use in improving the water-resistant properties oE the gypsum core comprises wax-asphalt emulsion, species oE which are available commercially. The wax portion of the emulsion is preferably a paraffin or micro-crystalline wax, but other waxes can be used also. The asphalt in cJeneral should have a soEt:ening point of about 115F, as determined by the ring and ball method. The total amount of wax and asphalt in the nqueous emulslon will qenerally comprise about 50 to 60 wt.~ oE the aqueous emulsion, with the weight ratio of asphalt to wax varyinc~ ~Erom about 1 to 1 to about 10 to 1. Various metllods are known for preparing thc wax-asphalt emulsion, as reportecl in U.S. Patellt No. 3,935,021 to D.R. Greve and E.D. ~'Ncill, assiclllclcl to thc same assignee as the prcsellt invention. Commer-ciall~ available wax asphalt emulsiolls tha~ call be used in the lZS~27 composition o the present invention are sold by United States Gypsum Co. (Wa~ Emulsion), Monsey Products, ~No. 52 Emulsion) ancl Doug].as Oil Co. (DOCEI1 No. 1034). The amount of wax-asphalt emulsion used can be within the rarl~e oE about 3 to about 10 wt.~, preforrably about 5 to about 7 wt.~o, based on th~ total woicJht o the incJredients of the composition from which the set gypsum core is macle, snid ingredients including the water oF the wax-asp]-alt emulsion, but not including addi-tional amounts of water that are added to the gypsum composition or ormin~l an ac~ueous slurry thereof.

~ particularly preEerred material for use in improv-ing the water-resistant properties of the gypsum core comprises a mi~ture of materials, namely~ poly(vinyl alcohol) and wax-asphalt emulsion of the aforementioned type. The use of such additives to improve the ~ater resistance o gypsum products is described in aEorementioned U.S. PEI tent No. 3,935,021.

The source o the poly(villyl alcohol) is preerably a substantially completely hydrolyzed form of poly(vinyl acetate), that is, about 97 to lOOQo hydrolyzed polyvillyl acetate. The poly(vinyl alcohol) should be cold-water insolublo and soluble in water at elovated temperatures, for example, at temporaturos of about 140 to abou-t 205F. In ~Jenoral, a 4 wt.C ~ater solu-tion of poly(vinyl alcollol) at 20C will have a viscosity of about 25 to 70 cp as de-termilled by mealls of the lloeppler falling ball rnethc)d. (`ommercially availablo poly~vinyl alcohols) for use ~L2S~

in the eomposition oE the present invention are available from E. I. du Pont de Nemours and Company, sold under the trademark "Eivallol" and fron~ Monsanto Co., sold under the ~rademark "Gelvatol". Examples oE sueh produets are Elvanol, Grades 71-30, 72-60, and 70-05, and Gelvatal, Grades 1-90, 3-91, 1-60, ancl 3-60. ~ir Produets Corp. also sells the prod-let as ~1S-42.

The amounts o~ po].y(vinyl aleohol) ancl wax-asphalt er.lulsion used should be at least about 0.05 wt. % and about

2 wt. ~ respeel:ively. The preferred amounts oE poly(vinyl aleollol) and wa~:-asphalt emulsion are about 0.15 to about 0.4 wt. ~i and about 3.0 to about 5.0 wt. % respectively. Unless statcd otherwise, the term "wt. ~" whell used hel-ein and in the elaillls rneans weiclht percent based on the total weicJllt of the incJrediellts of the eomposition from which the set cJypsum eore is made, said ingrediellts ineludincJ the water of the wax-aspllcllt emulsioll, but not includill~l additional amounts oE
wal:c~r tllat are added to the gypsum eomposition Eor forming an aqueouci slurry tllrnreof.

.~n attrcletive feature of the present invention is that the Eibrous mat-Eaeecl clypsum support member ean be made uti]izing exist:ing wallboard manuEacturincJ lines, for example, as showll sornewhat diaclramatieally in Figure 1. In eonventional Easllic~ll, dry in~JI-edients (not showll) from whieh the gypsum core is Ec~rin~cl are l~l-e-lllixed and thell Eed to a mixer oE the type ommon~y rerel-red to as a pin rmi~er 2. ~ater and other liquid constituents (not shown) used in making the core are metered into the pin mi~er 2 where they are combined with the dry ingredients to form an aqueous qypsum slurry. ~oam is generally added to the slurry in the pin mixer to control the density of the resulting core. The slurry ~ is dispersed through one or more outlets at the bottom of the mi~er 2 onto a moving sheet oE fibrous mat 6. The shect oE Eibrous mat 6 is indefinite in length and is fed from a roll (not shown) oE the mat.

As is common practice in the manuEacture oE convention-al paper-faced gypsum board, tlle two opposite ed~e portions of the fibrous mat 6 are progressively fle~:ed upwardly from the mean plane oE the mat 6 and then turned inwllrdly a~ the margins as to provide coverings Eor the edges of the resultincl board ~0. In Figure l, this progressive fle~ing and shaping of the edges of the mat 6 are sho~n Eor only one side ed~Je oE the mat and the conventional guiding devices which are ordinarily employed for this purpose are omitted from the figure for the sake of clarity.
Figure 7 shows an edge of the set gypsum core ~2 covered bv the overlapped edge portion 6A o~ the mat 6. Fi~Jure 7 shows also score marks lO and lOA of the mat 6, the scorc marks permittin~J
the formation of good edges and Elat surfaces. The score marks lO and lOA are made by a convcntional scorincJ ~hcel 12. An advan-tage of using the preferred form of g1ass fiber mat is that it is capable of being scored and ed~;ed likc conventional paper facing.

172~

~ nother sheet of Eibrous mat 16 is fed Erom a roll (not shown) onto the top of the slurry 4, thereby sandwiehinq the slurry between the two movinc~ fibrous mats which form the facinc~s oE t:lle set cJypsum core 42 whieh is formed from the slurry. The rnats 6 alld 16 witll thc sl.urry 4 sandwiehed there-betweell enter ~:he nip betweell tl~e upDer anc1 lower Eorming or sl)apin~J roll.s 18 ancl 20, ancl are therearter reeeived on a eonveyer belt2Z. Conven~iollal eclge cJuiclillcl devices, sueh as indieated at 24 shape and maintain the edges oE the eomposite until the cJypsum has set suFfieiently to retain its shape. In due eourse, sequent.ial lengths o.E the board are eut and further processed by e~posure to heat which accelerates the dryinq oE
the board by increasing the rate oE evaporation oE e~ceess water in the clypsum slurry.

With reference to Fic3ure 7, it has been observed that the set gypsum of the core 42 is eEfective in Eorming satisEactory bonds witll the mats ancl betweell tlle edge portions of the over-lying mat lG and the overlapped edge portion 6,~ of the underlyincJ
mat 6, thus makinc~ it unnecessary to use a bond improver in the slurry or an edcJe paste to form the aEorementioned bonds.

The pre.rcerred Eorm of mats 6 ancl 16, as shown in Figures 2 and 3, comprises glass Eiber Eilamellts 30 oriented in random pattern and bound tocJether with a resin binder (not shown).

~LZ~7~

A preferred Eorm of glass fiber mat-faced gypsum board 90 is shown in Figures 9 and 7. It comprises one in whieh the set cJypsum oE the core 42 penetra~es substantially through the thickness of the mat 6 over substantial area portions thereoE and in whicll the set gypsum oE the eore ~2 penetrates the mat 16 partially, with the surEace beinc) thus substantially Eree o set cJypswn. The gy~sum--Eree surEaee oE mat 16, as seen in Figure 8, is hic~hly textured, and provides an e~eellent substrate for adhering thereto an overlying eomponent inasmueh as it eomprises many interstices into whieh an adhesive eomposition eall flow and bond.

In shippincJ gypsum board, it is eonvenient to paekage two boards 90 and ~OA together tSee Figure 10 and 11), with the c11ass fiber gypsum-free surfaces 41 and 41A in faee -to faee relationship, and thus proteeted, and with the gypsum-eoated surEaces (Eor example, 43A in Figure 11) forming the outside of the packacle. The set gypsum on the outside surEaees helps to keep the board Erom being damacJed durincl handling, shipping and storage, and proteets the skin of those who eome in eontaet with the board from being irritated by the glass fibers of the mat.

The ptlrase "substantially penetrated by set gypsum", as used herein, means that the set gypsum oE the eoxe, e~tends Erom the mat sur~aee whicll is conticJuc)us to the core to tlle outer mat surEace and eoats glass Eibers on tlle outer surfaee with a thill fi:lm oE set 9ypsulll to the exten~ that the outline of glass ~ZS~7~

fibers ean be seen through the thin film oE set gypsum. The phrase over substantial area portions of the outer surface as used herein means that about ~0 to about 75% of the outer surEaee area oE the mat i5 substantially penetrated by set gypsum. Preferably about 45 to about S5~ of the outer surface area of the mat is substantial].y penetrated by set gypsum.
~ecordingly the gypsum-coated surface Oc this preferred embodi-ment of the board eomprises a surface that has a roughened or patterned appearanee; it does not comprise a smooth eontinuous coati.ng of set gypsum. This preferred form of board can be formed with.relatively small amounts of gypsum slurry being deposited on the underlyincJ support surEaee thus minimizing the need to elean the surfaee.

Tlle need for sueh elealling ean be substalltially avoided by adjusting the viseosity of the slurry so that it penetrates but part-way through the underlyincl Eibrous mat for e.~ample up to about 50~ of its thickness. Thus this preferred form of board llas two qyps-lm-:Eree Flber-faeed sur~ace~.

The manufaeture of the aforementioned preferred forms oE board ecin be aeeomplislled by controllinq the viscosity of the aqueous slurry oE the caleined c~ypsum in a manner sueh that the slurry petletrates the underlyillcl and overlyillcl mats to the des;red de~lree. 1ll mclnuFaeturinc~ eaell oE the aEoremelltiolled preferred Ec>rms of board tne visecsi.ty of the slurry should be sueh that it penetrl~:es about 10 to 50O of the thic~rless of the overlying mat OVCl- the elltile sul-Fice arccl thcreof.

~Z5~2~

The recommended means for controlling the viscosity oE the slurry is to acld thereto a viseosity-control agent. Such viscosity-control aqents are known in the field of yypsum board manufacture. A prcEerred viscosity-control agcnt is paper fiber.
Examples oE other agents that can be used are cellulosic thiek-eners, bentonite clays and starches.

The particular viscosity values that are used in the manuEacturing operation can vary from one application to the next, depending on the porosity of the mat, and the desired penetration oE the slurry. AccordillcJly, Eor any particular application, the viscosity value is best determined empirically.

In using the preEerrccl Eorm oE cJlass fiber mat, as described above, to manuEacture the aforementioned preEerred Eorms of board, developm~ntal work l-as shown that satisEactory results can be achieved utilizillg a cJypsum slurry having a viscosity within the range oE about 5000 Lo 7000 cp. As usec~ herein, the viscosity value reEers to Brookfield viscosity measured at a temperature of 70F at lO rpm utilizing paddle No. 3. It should be appreciated that the amount oE viscos:ity-control agent addcd to the slurry to give the desired viscosity will vary depending on the particular agent used and the speciEic viscosity desirecl.

In preEerrcd form, the core oE the fibrous nnat-aced cJypsum board has a density of about 40 to about 50 lbs/cubic ft., most preferably about 42 to about 45 lbs/cubic ft. The manuEacture ~2~)7;2~

of cores having densities within the preferred range ean be eEfected by using kllown techniques, for example, by introdueing an appropriate arnount of foam into the aqueous gypsum slurry from which the core is formed. There are weight advantacJes that can be realized by the use of fibrous mat-faced gypsum board in EISystems in that Eibrous mats which are lighter in weight than conventional paper EacincJ are available. For example, the weight oE a widely used paper faclncJ in the manufacture of eon-velltional cJypsum sheathing is in the range oE about 120 lbs/1000 sq. ft. of board, whereas the weight of a preferred form of glass Eiber mat for use in the present invention is about 40 lbs/1000 sq. ft oE board.

TurnincJ now to Eigures 12 and 13, there is shown therein an example of an exterior insulatinq system fabricated in aceor-danee with the present invention and eomprising the exteriorportion oE the building 81. The EISystem 80 eomprises panels of fibrous mat-Eaeed board 82 affixed by nails 8~ to wood framing ~6.
foamed polystyrene panel 88, about 1 ineh thie~, is adhered to the fibrous mat-faeed board 82 by adhesive 90. ~ reinforeincJ
member eomprisin-~ glass fiber skrim 92 is sanclwiehed between the polystyrene panel 88 and the final finishing material 9~ by adhe-sive 96.

Various of the preferrecl Eorms oE the qypsum board of the present invention can be used also to good advantage in place oE eonventiollal CJypsulll sheatllillcJ in applications other than XISystems. Thus, the preEerred Eorms oE board can be used as an UllClerlyillCJ support SUl-raCe WlliCIl is covered with overlying finish-inc1 matcriclls, ~or exalllple, alumin~ , wood siding, plastcr and ~ort~an<1 cemellt stucco.

lZS~'~2'7 EX~PL~S

The formulation set forth below is an example of a prcEtrrcd aqucous gypsum slurry wllich can be used in making the core of a clypsum support member in accorclance with the present invention.

ConstituentsLbs./1000 sc. 't. of board calcined gypsum1380 (CaSO l/2 H2O) wa~/asphalt emulsion 130 lOaqueous solution of lO wt%
poly(vinyl alcohol) 56 papcr Eiber 15 set accelerator 6 ammonium lauryl sulfonate (foaming agent) calcium lignosulfonate(clispersincJ agent) 2 water 260 The wax/asphalt emulsion used in the above formulation contained appro~imately 48 wt.% solicls oE which about ll wt.% was paraffin wa~ and about 37 wt.% was asphalt. The set accelerator comprised about 80 wt.% po~ash, about 12 wt.~ liqllosul'onate and about 8 wt.% ground qypsum.

The above c-ormulation was used to prepare gypsum board, the surface3 of wllicll wert: covered witll nonwoven fiber glass nnat.
'l`he Illa~ was composecl of glass fiber filaments oriented in a ralldom paLterll bollclccl to~Jetller by an adht:si~.e reEerrtd -to by tht manur;lctclrcr as a "mo(liricd urea-Eol-m-lld~ d~o rc~s;n". 'Ihe mat ~5~727 had a thiekness o~ 33 mils, was more porous than paper of the type used as the cover sheet o'c gypsum wallboard, and was not sigrlifieantly wea~ened by water. The air permeability of the mat was 700 CF~I/s~. ft. (test method FG 436-910~. The mat is availal-lc commercially as D[il~-GI.~SS 7502-2 lbs. and is an example o a preferrecl fi~rous mat for use in the praetiee oE
tlle present invention.

Continuous length board was made from the above gypsum slurry and glass fiber mat on a eonventiol-al wallboard machine.
The slurry was fed onto a movinci sheet of the mat as it was unrolled Erom a roll onto a movincl support surfaee. The mat had a width oE about 51 inches and was scorcd continuously by eonventiollal scoring blades prior to the depositioll of the slurry thereon. Each edcie of the mat was seored with two seore marks, with eaeh oE the outer seorcs beinci about 1 ineh from its respective edqe oE the mat and cach o~ ~he inner seores being about 1 1/2 ineh from its respeetive edcie. ,~fter the slurry was deposited on the mat, the edqes were folded at the seore marks and overlapped on top of tlle slurry. (The gypsum eore formed Erom this operation had a width of 47 7/8 inches and a thickness oE 1/2 ineh.) Mat Erom another roll thereof and having a width of ~7 1/2 ineller. was Eed onto lhe top oF the gypsum slurry and the overlapped edge portions of the underlyinci mat. The gypsum slurry penetrated the overlapped edge portions and served to bond tlle edcie portions oF the overly;l-~i mat to the overlapped edge portiolls of ~!~c un(lerlvillci mal:.

~2~'7Z7 The viscosity oE the cJypsum slurry was about 5900 cp at 70~. At this viscosity, the slurry penetrated substantially through Some portions of the underlyincJ mat to form a thin film thereoE on about ~0 to 50~ oE the area of the outer surface of thc- mat. Rs the CJypSum in the film set, substantial portions oE the outer surface oE the mat were covered with a thin film oE
set cJypsum. 'l'he surEace had a roughened appearance with outlines o the cJlass Eilaments being observable underneath the thin coat-in(Js of yypswll which covered them. Ilowever, at the aEorementioned viscosity, the slurry penetrated but a portion (about 5 mils) of the thickness oE the overlyiny mat over the entire area thereof, witll no slurry beiny observed on the outer surface of the mat.
As the yypsum set in the intermediate portions of the mat that were penetrated by the slurry, it formed a bond that included a mechanical interlock with the set cJypsum core.

The continuous lenytll board is cut into lenyths of about 8 Eeet. Dryincl oE tlli- yypsum board is accelerated by heatincl in an OVi?ll at 350F for about 2 hours and until the board is almost dry and thc!ll at 200F for about 1 hour until it is ~lried completely. Tl-e clensity of the board is about ~3 lb. cu.ft.

The gypsum-Eree surEaces oE panels (2' ~ 2') of ylass Eiber-faced boards as described nbove were adhered to panels of expanded polystyrene utilizincl two different commercially available adhesive systems. In one system, hereaEter "System A", one oE the faces of a panel of expanded polystyrene havincl a thickness of '~2~37Z7 about l inch ancl 2 X 2 was smeared with an adhesive mixture comprising cement sand and resin binder utili~ing a 3/8 X

3/8 toothcd trowel. The panel was then adhered to the c31a55 fiber-faced cJypsum board. ThereaEter glass fiber reinforcing rnesh was applied to the other face of the panel of expanded polystyrene and a decorative finish was applied to the mesh.

In the other system hereaEter System B the same steps as described above Eor System A wcre followed except that an acrylic adhesive was applied to the gypsum-free surface of the board and the polystyrene panel adhered thereto.

Two additional systems like Systems A and B above were assembled except that conve11tional papcr-faced cJypsum sheathincJ
was substituted for the cJlass fiber-faced cJypsum board in each of Systems A and s.

The intecJrity of each of the systen1s was eva3uated usinq ] l/2 X l l/2 cross-secticnal cubes which were extracted from the systems ~nd w1-ich were pulled apart in a tensile test apparatus. T1-e results oE the testing are set forth below.

Fiber Glass- Papcr-_y tem Facec1 Bo~rcl Faced 13Oard A 100% break in ~56~ break in the the polystyrene paper 33~ break paneL in the polystyrene n 100~ break in 100o break in the the polystyrene paper panel ~ ;~5U~27 Fro:n tlle above resulLs, it ean bc~ seen tllat tr-e USC of thc.~ qlasr.
fiber-raecd clyps~ supl)(,rt surfaee ilnprc~ve(l signi.fieanLl,~ the stren~Jth o~ tl-le a~sembl~ in that tensi]e cailure was transferrc?d Erom Lhe paper eover or Lhe cJ~psun, sheatilincl to the foamed S polystyrene, with no E.li.lure at all experiencc?d in the glass fiber mat or tlle clyps~lm eore to WlliCil it was aclllerecl. Thus, i~
shoulcl be a~,preeiatocl ~.hat, in aeeorclallee Witil tlle present inven-tion, t~lC .inl:eclri~y or all r[Sy.stelll ean l)e imploved sic~nifiealltly beeause it is no 1.011CICJ' CleL-CIlCIent U~C)OIl tlle ply strencJth of a paper eovo~ sllocAt, l>ul: uporl a eomponollc llavillc~ mueh hic~iher strengtl Glass ~iber-aeecl cJypsum boarcls, macle as cleseribecl above, alld witll the:ir edcJes proteeted, were plaeecl outcloors for severa].
IllC)ntlls allCi eXpOSC(l LC) Llle e.lemellts. Dllr;nq ~ilat period, tlle boarcis wel-e oxposecl to about 20 inelles of rain. AEtrr this expc,sure, ~he boards were examinecl and founcl to be in exeellellt eondition with no signs o[ clc?terioratioll.

Other outcloor Lests have shc~wn thclt ~JIass fiber mat-faeed CJy~sulll board in aeeorclanee wi.tll tlle pre.sent invelltioll and having a eore whic:ll .ineludes wax-aspllal.t emlllsi.oll as a water-resistallt aclditive bette.r resists deterio--atiorl than a like board having a eore whieh ineludes soclilllll methyl sil.ieollate as Lhe water-resistant adclit.ive.

Gypsuol boarcl eompr:ising a set cJypSUm eore ~aeed with a Eibrous mclt, as deser.i.be<1 hereill, alld preFerably qypsum board eolllprisillg a se~ ~Iypsulll eore sandwielled between two sheets oE
porous glass maL, ean be usecl to partieular aclvanta~lc? also as a -3fi-~2~;V7~

compollcnt o~ a sl~art wall assemb1y or similar asscmbly in thc inLerior oE a buildillc). Il~ such application ~he Eibrous mat-~accc1 ~oard calI bc ust?(l ~o pnrticular a~lvan~age in placc oE con-vcntiolIal pallcr-raccd C~;pSulll core boart3 or sIIar~ lincr pantls the corc of whicIl generally inc1udes fire-resis~allt atlditives.
~sselllblies oE this typc- c)enera]ly comprise me~al Eramework or studs Eor suppor~ of tlle clypsullI panels whicll form the walls of tl~e shaEts oE ele-va~ors stairwells ant3 the like. ~xamp1es of such assem~lir:s are slu-~wn in U.S. Pa~ent Nos. 4,~ 355; 4,324 082 ant3 4 3G-1 212 Fibrous ma~-faced board, as describe~ herein, can be uscd for e~amplt? in tllt3 assCll!~lies ~CsCl'ibCd i.ll thc DEolclllcnLione(I
patelIts ancl p~r~icularly a; tllc sha[t liner panel. For use in such applica~iolI, Ll1C corc oE thc board can inclu~e Eire resis-alIt ~ cs.

In sunu(lar;~ it call be saicI tllat chc prascnt invt-ntion provicIt?s in a prac~ic~a1 way impo)-alIt l`ullctiollaI imnrovelllents in cxterior Einisllill~Jsys~cllls for builclill~ls including particularl, axlcl-lc)l- ;nsula~ n;rlc"l!:, alltl in sllalt wall asscm~lies.

-3G ~-~,

Claims (28)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An exterior insulation system for a building comprising a glass mat-faced gypsum support surface, insulating material having an inner surface and an outer surface, the inner surface of which is adhered to said support surface by an adhesive material, the insulating material being substantially free of channels penetrating therethrough and between said inner and outer surfaces, and an exterior finishing material overlying the outer surface of said insulating material.

2. A system in accordance with claim 1 wherein said support surface comprises a plurality of glass mat-faced gypsum core panels in abutting relationship, with panels of said insulating material in abutting relationship adhered to said panels comprising said support surface, and exterior finishing material having weathering and aesthetic character-istics overlying said panels of insulating material.

3. A system according to claim 1 or 2 wherein said mat is a glass fiber mat comprising randomly distributed glass filaments bonded by an adhesive material.

4. A system in accordance with claim 1 or 2 wherein said support surface comprises panels of gypsum board, said board comprising a set gypsum core sandwiched between two sheets of porous glass mat, each of which has an inner and outer surface and a predetermined thickness, said mat comprising randomly distributed glass fibers bonded by an adhesive material, the inner surface of each of said mats adhered to said gypsum core by set gypsum of said core penetrating but part-way into the thickness of each of said mats, and wherein the outer surface of each of said mats is substantially free of set gypsum.

5. An exterior insulation system in accordance with claim 1 or 2 including a reinforcing member sandwiched between said insulating material and said finishing material.

6. A system in accordance with claim 1 wherein said support surface comprises panels of gypsum board, said board comprising a set gypsum core sandwiched between two sheets of porous glass mat, each of which has an inner and outer surface, said mat comprising randomly distributed glass fibers bonded by an adhesive material, the inner surface of each of said mats adhered to said gypsum core by a portion of the set gypsum comprising said core, the outer surface of one of said mats having portions thereof coated with set gypsum comprising portions of the set gypsum of said core, and the outer surface of the other of said mats being substantially free of set gypsum.

7. A system in accordance with claim 2 wherein said support surface comprises panels of gypsum board, said board comprising a set gypsum core sandwiched between two sheets of porous glass mat, each of which has an inner and outer surface, said mat comprising randomly distributed glass fibers bonded by an adhesive material, the inner surface of each of said mats adhered to said gypsum core by a portion of the set gypsum comprising said core, the outer surface of one of said mats having portions thereof cotated with set gypsum comprising portions of the set gypsum of said core, and the outer surface of the other of said mats being substantially free of set gypsum.

8. A system according to claim 6 or 7 wherein said insulating material is adhered to said mat having its outer surface substantially free of set gypsum.

9, A system in accordance with claim 6 wherein-said gypsum-coated mat is substantially penetrated by set gypsum over substantial area portions of the outer surface thereof, and wherein the set gypsum of the core penetrates but part-way into the thickness of the other of said mats.

10. A system in accordance with claim 7, wherein said gypsum-coated mat is substantially penetrated by set gypsum over substantial area portions of the outer surface thereof, and wherein the set gypsum of the core penetrates but part-way into the thickness of the other of said mats.

11. A system in accordance with claim 9 wherein about 45 to about 55% of the outer surface of said gypsum-coated mat is substantially penetrated by the set gypsum.

12. A system according to claim 9, 10 or 11 wherein said insulating material is adhered to said mat having its outer surface substantially free of set gypsum.

13. An exterior insulation system for a building having a support surface including gypsum board comprising a set gypsum core faced with a glass mat, the gypsum core including one or more additives which are effective in improving the water-resistant properties of the board in an amount at least sufficient to impart to the board improved water-resistant properties, insulating material having an inner surface and an outer surface, the inner surface of which is adhered to said glass mat by an adhesive material, the insulating material being substantially free of channels penetrating therethrough and between said inner and outer surfaces,and an exterior finishing material overlying the outer surface of said insulating material.

14. A system according to claim 13 wherein the core of said board absorbs less than 5% water when tested in accordance with ASTM method C-473 with only the edges thereof exposed.

15, A system according to claim 13 wherein the core of said board is sandwiched between two sheets of porous glass fiber mat and absorbs less than 5% water when tested in accordance with ASTM method, C-473 with only the edges thereof exposed.

16. A system according to claim 13 wherein the core of said board is sandwiched between two sheets of porous glass fiber mat and is prepared from a calcined gypsum composition containing at least about 3wt.% wax-asphalt emulsion.

17. A system according to claim 16 wherein said core is prepared froma calcined gypsum composition including also poly(vinyl alcohol).

18. A system according to claim 16 wherein the amount of said emulsion is within the range of about 3 wt.% to about 10 wt.%.

19. A system according to claim 18 wherein the amount of said emulsion is within the range of about 5 wt.%
to about 7 wt.%.

20. A system according to claim 17 wherein the amounts of said poly(vinyl alcohol) and said wax-asphalt emulsion are at least about 0.05 wt.% and at least about 2 wt.% respectively.

21. A system according to claim 20 wherein said amounts are about 0.05 wt.% to about 0.4 wt.% and about 3.0 wt.% to about 5.0 wt.% respectively.

22. A system in accordance with claim 13 including a plurality of said boards in abutting relationship and panels of said insulating material in abutting relationship adhered to said glass mat, and wherein said exterior finishing material has weathering and aesthetic character-istics and overlies said panels of insulation material.

23. A system in accordance with claim 22 wherein said set gypsum core is sandwiched between two sheets of porous glass mat, each of which has an inner and outer surface, said mat comprising randomly distributed glass fibers bonded by an adhesive material the inner surface of each of said mats adhered to said gypsum core by a portion of the set gypsum comprising said core, the outer surface of one of said mats having portions thereof coated with set gypsum comprising portions of the set gypsum of said core, and the outer surface of the other of said mats being substantially free of set gypsum.

24. A system in accordance with claim 23 wherein said mat is a glass fiber mat comprising randomly dis-tributed glass filaments bonded by an adhesive material.

25. A system in accordance with claim 23 wherein said insulating material is adhered to said mat having its outer surface substantially free of set gypsum.

26. A system in accordance with claim 23 wherein said gypsum-coated mat is substantially penetrated by set gypsum over substantial area portions of the outer surface thereof, and wherein the set gypsum of the core penetrates but part-way into the thickness of the other of said mats.

27. A system in accordance with claim 26 wherein about 45 to about 55% of the outer surface of said gypsum-coated mat is substantially penetrated by the set gypsum.

28. A system in accordance with claim 26 wherein said insulating material is adhered to said mat having its outer surface substantially free of set gypsum.