CA1309831C - Fibrous mat-faced gypsum board - Google Patents
Fibrous mat-faced gypsum boardInfo
- Publication number
- CA1309831C CA1309831C CA000616157A CA616157A CA1309831C CA 1309831 C CA1309831 C CA 1309831C CA 000616157 A CA000616157 A CA 000616157A CA 616157 A CA616157 A CA 616157A CA 1309831 C CA1309831 C CA 1309831C
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- Prior art keywords
- gypsum
- mat
- core
- board
- water
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
A fibrous mat-faced gypsum board is provided, for use in an exterior finishing system for a building, including particularly an exterior insulation system, and for use in a shaft liner panel and a shaft wall assembly. The gypsum board has a set gypsum core faced with a fibrous mat. The core includes one or more additives that 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.
A fibrous mat-faced gypsum board is provided, for use in an exterior finishing system for a building, including particularly an exterior insulation system, and for use in a shaft liner panel and a shaft wall assembly. The gypsum board has a set gypsum core faced with a fibrous mat. The core includes one or more additives that 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.
Description
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FIBROUS MAT-FACED GYPSUM BOARD
Field of the Invention-This invention relates to improvements in exterior ~inishing systems such as, for example, exterior insulation syste~s for buildings, and also to improvements in shaft wall assemblies for buildings. More particularly, ~his invention relates to an improved structural component ~or us~ as a support sur~aca in an exterior finishin~ system, including an exterior insulation sy~tem (sometimes referred to herein for .
convenience as ~EISystem). In addition, the present invention encompasses improvement~ in hollow shaft wall a~semblies, ~or example, those used in constructing elevator sha~ts and stairwells.
~his invention will be described initially in connection with its use in EISystems, but, as will be explained hereinafter, its use has wider applicability.
EISystems are presently being used more and more widely to insulate existing buildings and buildings under construction including indus~rial, oommercial, municipal, in~titutional, and residen~ial buildings. ~ns~allation o~ a typical EISystem in new construction generally involves the , - 13~1~83~
following sequential steps: (A) constructing a frame ~or support of the outside wall of a building; (B~ affixing to the frame structural panels to provide a smooth continuous surface for the support of other of the components of the EISystem; (C) affixing to the support sur~ace panels o~
insulation; and (D) affixing to the panels of insulation a mesh-like material which in turn is covered with an exterior finishing material having weathering and aesthetic properties.
Such systems are designed to be not only highly insulative in character and attractive in appearance, but also waather resistant. EISystems can be used to advantage to conserve energy used for heating and to conserve energy used for air-conditioning.
EI5ystems have inherent advantages over interior insulating systems and, in addition, they can be used to better advantage than interior insulating sys~ems in many applications.
For example, ~he range of temperature variation in structural components comprising the walls of a building insulated from the outside is less than that for such components in a building which is insulat~d from the inside.
Accordingly, such structural components when insulated ~rom the outside are subjected to siynificantly lower amounts of stress caused by thermal expansion and contraction than those insulated ~rom the insideO This is particularly advantageous in applicationY where the structural componenks comprise materials having markedly different co f~iciants of expansion, as is often the case. In addition, the interior space in a building having an EISystem tends to have a more uniform temperature and be less drafty than that o~ a building insulated ~rom the inside.
Certain buildings are not capable o~ being insulated from the interior except that valuable inside space is los~ ~o the system. The installation of an EISystem does not dlsturb "` 130983~
the inside space of the building.
An EISystem can be used also to mo~ernize or otherwise renovate the exterior of a ~uilding in nee~ of renovation. Various of the EISystems which are-commercially available give the architect a wide range of aesthetically pleasing designs from which to choose. In addition, the oost of installing an EISystem is relatively low when there is taken into account both the costs of othar systems and the improved thermal efficiencies that can be realized. The relatively light weight of both the insulation and the exterior finish in an EISystem i5 particularly ~dvantageous in new construction because of reduced foundation requirements.
Th~re are, howev~r, problem~ associatad with the design and/or installation o~ EISystems. As will be discussed in detail below, various o~ th~ problems stem from ~he type of material which is used as t~e supporting member for the insulating and exterior finishing materials of the system.
The pre~ent invention involves improvements in such suppor~ing member.
Reported DeveloPments As mentioned a~ove, a typical EISystem includes a supporting member to which there is affixed insulating material, which in turn is covered with an exterior ~inishing material. An exemplary EISystem includes a wood or m~tal fram2 which i mechanically held in place by nails or screws to appropriate structural members o~ the building, with panels of the supporting member in turn mechanically affixed by natls or screws to the frame. The supporting member, which typically consists of a smooth continuous surface comprising individual panels of material positioned in abutting relationship, must be strong enough to carry tha we~ght of the components which overlie it, including the insulatin~ and exterior finishing materials Although low density, light ~, ' 13~831 weight insulating pan~ls of expanded polystyrene are used widely in such systems, the exterior finishing material i5 yen~rally a much denser and heavier weight material, for ëXa~pl~ n acrylic resin/cement coating that may include *ec~rative aggregate embedded therein.
Certain of the commercialized EISystems include the use of panels of a Portland cement-based composition as the structural member for the support of the overlying panels of insulation and exterior finishing material. It is believed that such cement-based panels are described in U.S. Patent No.
3,284,980 which discloses a building panel comprising a core consisting of a mixture of hydraulic cement and light-weight aggregate (for example, perlite) sandwiched between sheets of ~ibrous material (for example, woven glass fiber screen), which are adhered to the faces of the core by separate layers o~ bonding material containing at least 50% hydraulic cement.
Although 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 weigh~ about 40 1/2 po~nds. The handling and installation of such panels lead to the consumption of relatively large amounts o~ energy. This is a burden to workmen and makes ~ransportation o~ the panels relatively costly.
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A material which is used more widely in EISystems than the a~orementioned cement board is gypsum board, ~ha~ is, panels co~prising a core of set gypsum (calcium sulfate dihydrate) ~andwic~ed between paper cover sheets. The particular typë o~ gypsum board that is recommended for use in EISystems is known as-~gypsum sneathing~ which is gypsum board designed for use on the exterior o~ ~uildings where it serves as an underlying sur~ce wnich is covered wi~n~uc~ m~terials as aluminum, wo~d si~ ;'Portlan~'ceme~t"s~c~ aA~ n the cas~ o~!an-~ISys~em,-with insu~at'ing'an~`extërior fln"ishlng materials. C~nv~ntion~'l gypsùm sheathing, as opposed to conventional gypsum wàll~oard for use in th~ interior o~ a 30~8~1 building, includes a set gypsum core which contains one or more additives which improve the water resistance of the set core. The gypsum core o~ commercially available wallboard can absorb as much as 40-50 wt.% water when immersed ther in at a temperature of 70F. for about 2 hours. As the absorption of water tends to substantially reduce the strength of the core, materials which reduce the tendency o~ the core to absorb water are included therein. In addition, sheathing has water-repellant paper cover sheets which shed water. This is temporary protection for the sheathing before it i5 installed and before it is covered with the exterior finishing material.
Gypsum sheathing has many desirable characteristics which make it suitable for use in an EISystem. For example, such sheathing has relatively good fire-resistant properties, it is relatively li~ht in weight, it has satisfactory water-resistant properties and it can be mechanically affixed in convenient fashion to a metal or wooden frame which underlies the sheathing.
Notwithstanding the aforementioned, concerns have been expressed respecting the use of such gypsum sheathiny in EISystems. By way of background, it is noted that it is conventional in the industry to affix panels of insulating material to the underlying support of gypsum sheathing by the use of an adhesive material and, in turn, to af~ix by the use of adhesive material~ each o~ the plies which overlie the panels of inisulation. Except for the use of mechanical fastening meani~ in the construction of the frame of the building and in affixing the gypsum sheathin~ to the frame, all of the components of the EISystem are in effect glued ~et~e~ ~. .... . , ~ . ... .
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Tests designed to evalua~e the cohesive ~trength of and the a~hesive stre~qths between the various components comprisîng the EISy~tem have show~th~ itial f~ilu~e ~;
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~pulling apart) of the system occurs not in any of the adhesive layers, but in the paper cover sheet of the gypsum sheathing. Such cover sheet 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 monolithic sheet of paper. Accordingly, the cohesive strength of the paper can be characterized as the we~k portion of the system.
Another concern respecting the use of gypsum sheathing in EISystems of the aforementioned type is tha~
water leakage through the system can lead to the deterioration of the bond between the paper cover sheet and the gypsum core.
(Although the system is designed to be waterproof, there are circumstances where defects in one or more plies o~ the system and/or unusually sev~re environmental condition~ are the cause of water seepage). It should be appreciated that deterioration of thi bond can lead to cracking of tha Pxterior finish, and possibly even collapse o~ portions of the system a~ the component which is adhered to *he paper cover sheet pulls apart.
In an effort to overcome th~ aforementioned type problems, it has been proposed to affix the insulatlng material to the underlying gypsum sheathing by the use of mechanical fasteners which extend through the insulating material, the core of the gypsum sheakhing, and into the frame. This approach to the problem has the disadvantage that the work time involved in installing the system is increased significantly inasmuch as it is much mor~ time consuminq to install fasteners than to apply an adhesive. Another shortcoming of thq fastener approach is that the fasteners provid~ paths for the flow o~ water which may penetrate the ~... .
system and weaken ~he bond between the paper cover shee~ and gypsum core, as mentioned abova.
Irres~ective of how the insulating material is affixed to the underlying gypsum sheathing, there is another problem connected with the use of sheathiny in EISystems.
Because of it5 susceptibility to degradation by water, care must be taken to protect the sheathing from rain and other moisture conditions which may~b~ encountered as the sheathing is stored at the ~ob site awaiting use and during installation. Taking such protective precautions consumes time, causes inconvenience, and sometimes causes delays in installation of the system - all of which tend to increase costs.
Although gypsum sheathing has a water-repellant paper surface which provides some limited protection against water degradation, this type of surface forms a relatively poor bon* with water-based adhesives which are used to adhere to.the.surface other components of the EISystem.
The present invention is a support member; for use in EISystems and sha~t wall assemblies, comprised of an improved gypsum-based structural component which is modified in a manner suc~ that problems of the type associated with the use of conventional gypsum sheeting are either overcome or alleviated significantly.
5~MMARY OF THE I~VENTION
In accordance with the present invention, there i8 provided an improved structural support element comprising a fibrous mat-faced gypsum support surface for use in an exterior finishing system, including exterior insulating systems, for buildings and in shaf~ wall assembliesr one embodiment of the present invention is a gypsum board comprising a set gypsum core sandwiched ketween two sheets of porous glass mat of randomly dist~ibu~ g~ss~hbe~1.bonded by an adhesive material. Each mat has~a~iinner an~ outer surface, the inner surface of which ls adhered t~ ~he.gypsum core by a portion of the set gypsum comprising the core. The ou~er surface of one of the mats has portions coated with the set gypsum o~ the core. The outer surface of the other of the 3~9831 mats is substantially free of set gypsum.
Preferably, the gypsum core has one or more additives which improve the water resistance thereof. As will be seen from examples repoxted below, a structural member comprising a water-resistant gypsum core faced with glass mat, which itself is hydrophobic, has outstanding weathering characteristics.
An additional preferred form of the present invention comprises a gypsum board having each of its core faces covered with a porous glass fiber mat, with the ~at of one of the faces being adhered to the core by ~et gypsum penetra~ing but part-way înto the thickness of the mat and having its outer.surface substantially free of set gypsuml As will be described below, the glass ~iber mat surface, which is free of set gypsum, provides an excellent substrate to which overlying panels of insulation can be adhered.
In one embodiment of the above form of the invention, the out~r sur~ace of the mat of the other corR face i5 also substantially free o~ set gypsum, with set gypsum o~
the core penetrating but part-way into the thickness o~ the mat. As will be described below, there are manufacturing advantages which accompany the production of gypsum board o~
such embodimentO
In another embodim~nt of the aforementioned ~orm o~
the pre~en~ invention, the set gypsum of the core penetrates substantially thr~ugh the.thickness of the mat o~ the other c,ore fac0 o~er.s~bstanti~1.area portions thexeof in amoun.~s which are suf~icien~t~ coa~ gla~s ~i~ers of the mat with.a thin film of s.et-gyps.~, but~not ~ufficient t~ form a smooth, continuou~.~oating o~ se~..gypsum. ThiS embodiment in which signi~icant portions o~ the outer surface of the mat have set gypsum therean provides a protective sur~acQ i~-.a .~wo,~board package in which the~boards.are-packed to-~ether ~i~h the .
---- 130~31 gypsum-~ree surfaces in ~ace-to-face relationship and with the ~ypsum covered faces being exposed. More particularly, this preferred form of board comprises a set gypsum core sandwiched between two adhering sheets o~ porous glass mat of predetermined thickness, each of said mats ha~ing an inner and outer surface and comprising randomly distributed glass fibers bonded by an adhesive material, the inner surface of each of said mats being adhered to said gypsum core, and with set gypsum o~ the core at one sur~ace thereof penetrating substantially through the thickness of one of said mats over subs~antial area portions thereof and coating substantial area portions of the outer surface thereof and with set gypsum of the core at the other surface thereof penetrating but part~way into the thickness of the other of said mats, the outer surface of the other o~ said mats being substantially free of~
set gypsum.
Still another aspect o~ the present invention comprises a process for making the aforementioned embodiments 2Q o~ gypsum board, that is, the embodiment in which bokh outer sur~aces of the mats ars substantially free of set gypsum and the embodiment in which the outer sur~ace of one of the mats is substantially ~ree of set gyp~um and that of the other mat has set gypsum thereon. The proce~s includ~s known steps used heretofore in manufacturing in continuous fashion conventional wallboard and known glas~-fiber mat-faced gypsum board, but di~fers there~rom in that the viscosity of the aqueous gypsum slurry from which the board core is made is controlled in a manner such that the slurry penetrates into the mats to the extent needed to~achieyç the desired result. .The basic steps of the proc~s comp~is~
. . .
(A) forming an aqueous slurry of calcined qyp~um;
(B) continuously feeding said aqueous slurry on~o an underlying, moving and supported porous fiber glass mat having a predetermihed thickne~s and an outer surface;
.(Cl forming said deposited~slurry a~ it i~ carried ' .
309~31 on said moving mat into~-a panel-like shapa; and (D) applying to the~top surface o~ said panel like shape of ~lurry an overIying porous f~ber glass ma~ of predetermined thickness. ; - : ~ -. ~
In forming gypsum boaxd in which ~oth of the outer mat surfaces are substantially ~ypsum-free, the viscosity of the slurry is maintained at a value such that portions of said slurry penetrate but part-way through the thickness of each of said underlying and overlying mats and the panel-like shape of slurry is maintained a~ the calcined gypsum sets to form a set gypsum core having adhered to its surfaces the und~rlying and overlying fibQr glass mats.
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In ~arming the gypsum-coated/gypsum-~ree form of glass fiber-~aced board, the viscosity of the slurry is maintained at a valu~ such tha~ portîons of said slurry penetrate substantially through the thickness of said underlying m~ over substantial area portions thereof to coat substantial area portions of the outer surface and at a valu~
such that portions o~ said slurry penetrate but part-way into the thickness of said overlying mat.
There are numerous advantages whi~h flow from the use of the present inven~ion. ~n EISystem which includes a fibrou mat-faced gyp~um support surfa~e that has affixed thereto in~ulating mat~rial hy adhesive only, that i , without fastening means which extend through the insulating material, has higher tensile or cohesive strength than a like sys~am which includes convantional paper-faced ~ypsum bo~rd. Testing of systems of ~his invention which include insulatio~ ih the form of expanded polystyrene panels has ~hown that lnitial failure is experienced by a pulling apart o~ th~ ex`pan~ed polystyrene panel, thus evidencing improvement in ~réng~h relative to conventional systems where initial faiiure is experienced in the paper plies of the g~psum support mem~ér.
The fibrous mat-faced surface of the gypsum support member i~
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water resistant in contrast to conventional paper cover sheets of gypsum board which can soak up water. This improved water resistance gives the applicator greater flexibility in selecting adhesives that can be used to adhare insulation directly to the mat-faced surface of the gypsum support element as adverse affects are not encountered by the use of water-based adhesives. The fibrous mat-faced surface of the gypsum support element is ~nailable~, and accordingly, it can be secured readily to an underlying frame or other substrate by nailing. In comparison to various of the commercially available systems, the improved support surface of the present invention has improved rigidity and strength uniformity in both the length and width dimensions of the system. Unlike conventional paper cover sheets, the fibrous mat does not expand or contract during the manufacture of the product; this reduces cockle and leads to uniformity of dimensions. The preferred embodiment of the invention which includes the use of a water-resistant core provides a substantially improved weather-resist~nt product which better re~ists degradation both within and outside of the system.
Figure 1 is a somewhat diagrammatic, fragmentary side elevational view illustrating portions of a manufacturing line for producing gypsum board of a type sui~able ~or use in the manu~acture o~ gypsum board prepared for use in accordanca with the present invention;
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Figur0 2 i~ an enlarged fragmentary sectional view, taken as indicated toward the lè~t of ~igure 1, of an underlying fiber glass mat used in the manufacture of the gypsum board;
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Figure 3 is a fragmentary plan view taXen as indicat~d by the line 3-3 on Figure 2;
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Figure 4 is an enlarged sectional view taken as indi~ated toward the right on Figure 1 and illustrating both underlying and overlying fiber glass mats, with intervening gypsum composition, used in the manufacture of the board;
Figure 5 is a fragmentary plan view taken as indicated by line 5-5 on Figure 4:
Figure 6 is a fragmentary bottom view taken as indicated by the line 6-6 on Figure 4 and illustrating the bottom surface of the underlying mat of the board;
Figure 7 is a transverse sectional view o~ an edge portion of the completed board, this view being taken as indicated by the line 7-7 on Figure 4;
Figure 8 is a further enlarged fragmenta.ry sectional view taken as indicated toward the top of Figure 4;
Figure--9 is a further enlarged fragmentary sectional view taken as indicated toward the bottom o~ Pigure 4;
Figure 10 is a view illustrating two complete gypsum boards fabricated according to the present invention and being assembled for packaging, with the top fibrous mats of the two boards presented toward each other;
Figure 11 is a view of two hoards assembled in th~
manner indicated in Figure 10 and bound together ~or purpos~s of shipping:
Figure 12 is a somewhat dia~rammatic ve~tical sectional view through the upper portion of an external building wall, a~ insulated in accordanca wi~h the presen~
invention; and .
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Figure 13 is an enlarged vertical sectional view taken substantially as indicated on Figure 12.
DETAILED DESCRIP~ION OF THE`INVENTION .-The essential components of an EISystem comprise insulating material which is sandwiched between an underlying support surface and an exterior finishing material which can be an integral part of the insulating ma~erial, ~u~ which is usually applied to the insulating material at the site o~
installation. From one EISystem to the next, there exist variations in structural details and components. For example, although the exterior finishing material may be a~fixed directly to the insulating material, various systems include a reinforcing compo~ent sandwiched between the exterior finishing material and the insulating material. The reinforcing component comprises generally one or mor~ plies of fiber glass reinforcing fabric or mesh which is adhered by suitable mastic to the sur~ace of the insulating material. In some systems, the support surfa~e is affixed to a wooden ~rame attached to the exterior surface of the outside wall of a building, whereas in other systems a metal frame is used. In certain applications, the support sur~ace may be affixed dixectly to the ext~rior surface of an outside wall, ~or example, sne comprising cinder blocks or concrete bloc~s. In new construction, the support sur~ace is typically af~ixed directly to the frame of the building. The adhesive or mastic for adhering together componants o~ th~ system tend~ to vary from one system to the next, and typically comprises specially formulated proprietary compositions. The improved support surface of the present invention can be used satisfactorily and to good advanta~e in EISystems which include overlying plies o~ insulating and exterior finishing materials~ and other optional components.
Presently, the most popularly used insulating material in EISystems is expanded or foamed polystyrene, a .
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13~9~3~
material which has good moisture re~istant properties.
Although it has desirably low water vapor transmission, it is not a vapor barrier, but instead is capable of breathing.
Rigid panels of expanded polystyrene are used most widely in EISystems. Such panels have satisfactory compressive strength and resilience and are presently available in thicknesses ranging ~rom 1/2 to 6 inches, widths from 6 to 48 inches and lengths ranging from 4 feet to 16 feet~ One commercially available system utilizes rigid, expanded polystyrene panels which are 2' X 4' X 1~.
other thermal insulating materials can be used in EISystems also. Examples of such materials include extruded polystyrene, polyurethane, isocyanurate, cement-based insulating plaster~, and phenolic foam. Insulating materials generally h~ve low thermal conducting and low density.
As mentioned above, various EISystems include a reinforcing component, for example, in cloth form, sandwiched between the insulating material and the exterior ~inishing material. Glass cloth is most widely used at the present time to reinforce the system, that is, to improve the impact strength of the s~stem. The particular type or types of glass cloth used and the number o~ plies thereof which are used depend on the impact resistance which is desired. Examples o~
reinforcing cloth or fabric which can be used in the system are woven glass, glass fib~r scrim and glass fiber mesh.
Installation of the reinforcing fabrir generally involves applying a suitable adhesive to the surface of the insulating material and then applying the fabric tAere~o. Additional plies of fabric can be applied if desired. A cement/acrylic resin is an example of an adhesive that can be used..
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The exterior ~inishing material can be affixed directly to the insulating material or to an in~ermediate surface such as, for exa~ple, the surfac~ Qf a reinfurcing member as described ab~ve. The exte~ior inishing material 983:1 has weathering characteristics and is preferably appealing in appearance. Presently, the most widely used exterior finish i5 an acrylic resin-based composition which is available in a paste-type fo~m which is spread or troweled on the underlying substrate. One type of such composition can be described as a ready-mixed synthetic resin plaster. Afte~ application, the resin sets to ~orm a tough~ weather-resistant solid material which adheres tightly to the underlying substrate. Such resin compo~itions are available commercially in a variety of colors. They include optionally aggregate which can vary in size. This allows the applicator to choose a particular composition which permits him to apply a finish that can vary in texture from fine to coarse. Finishes which have a stuoco-like appearance are popular. Small stones of various colors can be embedded in the composition ~or decorative purposes.
Examples of other materials that can be used as an exterior finish are Portland cement stucco including, for example, sand and larger aggregats.
The exterior finish can vary in thickness over a wide range, with a thickne s of about 1/16~ to about 1/4 being exemplary.
Turning now to a description of the improved support member for use in exterior systems of the present invention, it comprises a set gypsum core ~aced with a fibrous mat. The gypsum core is basically of the type used in those gypsum structural products which are known as gypsum wallboard, dry wal}, gyRs,um board and gypsum sheathing. The ~GO~ o~such a pr~duct is ~rmed by mixing water wi~h pow~red anhydrous calcium sul~ate or calcium sulfate hemihydrata (CaSO4;1/2H20), alsa known a~ cal~ined gypsum, and therea~ter allowing the mixture to hydrate or set into cal~ium sulfate dihydra~e (CaS04 2H20), a rela~ively hard material~ Tha car~ of the support member will in general ~omprise ~t ~east ~bout 85 wt.
percen~ set gyps~m. ~: ~
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, The composition from which the set gypsum core is made can include optional constituents, including, for example~ those included conventionally in gypsum shea~hingO
Examples of such constituents include set accelerators, foaming agents, and dispersing agents. As will be described in more detail below, a preferred gypsum core ~or use in the present invention includes one or more additives which improve the water resistant properties of the core.
The surface of the core to which the insulating material of the system is affixed is faced wi~h a fibrous mat.
The fibrous mat should be sufficiently porous to permit water in the aqueous gypsum slurry from which the gypsum core is made to evaporate therethrough. As described in de~ai~ beiow, lS the gypsum support element for use in the present inv~tion can be made ef~iciently by forming an aqueous gypsum s~urry which contains excess water and placing thereon the fibrous mat. Aided by heating, excess water ~vaporates ~hrough the porous mat as the calcined gypsum sets~
The ~ibrous mat comprises material which is capable of forming a strong bond with the set gypsu~ compri-~ing the core of the suppor~ sur~ace. Examples o~ such materials include a mineral-type material such as glass ~ibers and synthetic resin fibers. The mat can comprise con~.inuous or discrete strands or ~ibers and be woven or nonwoven in form.
Nonwoven mats such as chopped strand mat and continuous strand mat can bP used satis~actorily and are less costly than woven materials. ~he strands of such mats are konded together hy suitable adhesive. The mat can range in thickness, for example, from ~bout~ t~ about 40~mils, ~ith a ~hickness o~
about 25 to about 35 mil-s being pr~ferred. The aforementioned fibrous mats are known and are commercially available in many formS. . ..
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T~ pre~erre~ rou~ ma~ is a ~iber glass mat 30983~
comprislng flber glasa filaments oriented in random pattern and bound together with a- res~n bind~r. Plb~r glass mats of this type . . .
are commercially available, for example, those sold under the trademark DURA~GLASS by Manville Bullding Materials Corporation and those sold by ELK Corpora~ion as BUR or shingle mat.
Although improvements ln an EISystem can be realized by the use of a gypsum core which has but one of it8 surfaces faced with flbrous ma~ as descrlbed herein, lt is preferred that both sur~aces of the core be faced with substan~ially the ~ame f~brous màterial. If the surfaces of the core are faced with materials that have differqn~ coefficlent~ of expansion, the core tends to warp. Flbrous mat-face`d gypsum board and methods for making the same are known, for example, as described in Canadian Patent No.
993,779 and United State~ Patent No. 3,993,822.
As mentioned above, the preferred form of the fibrous mat-faced gypsum support surface comprises a gypsum core which has water-resistant properties. The preferred means for imparting water-reslstant properties to the gypsum core is to lnclude in the gypsum composltion from whlch the core ls made one or more additiveq which lmprove the ability of the set gypsum compositlon to resist beinq dagraded by water, for exam~le, to r~si3t dissolu-tion. In preferred form, the water xeslstance of the core is such that it absorbs less than 5 percent water when tested.in. ..
accordance with ASTM method C~473.
The fibrous mat for use in the present invention has substantially better water-rasls~ant properti~s ~han ~he conventiona.l paper facing of gypsum wallboar`d or sheathing.
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~L3~9~31 Nevertheless, evaluations have shown that the bond between the fibrous mat and gypsum core can deteriorate relatively quickly under the influence of water. For example, samples exposed to the weather showed loosening at the glass fiber facing within .
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~30~831 one to two months. In contrast, evaluations o~ water-resistant gypsum core faced with fibrous mat in accordance with the present invention have shown the bond between the mat and core resists being degraded by water for indefinite periods of time.
Examples of materials which have been reported as being effective for improving the water-resistant propertias of gypsum products are the following: poly(vinyl alcohol), with or without a minor amount of poly(vinyl acetate);
metallic resinates; wax or asphalt or mixt~res thereof: a mixture of wax and/or asphalt and also corn~lower and potassium permanqanate; water insoluble thermoplastic organic materials such as petroleum and natural asphalt, coal tar, and thermoplastic synthetic resins such as poly(vinyl acetate), poly(vinyl chloride) and a copolymer of vinyl acetate and ~inyl 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 fonm of an emulsion and either residual ~uel oil, pine tar or coal tar; a mixture comprising residual fuel oil and rosin; aromatic isocyanates and diisocyanates; organohydrogenpolysiloxanes; a wax-asphalt emulsion with or without such materialæ as potassium sulfate, alkali and alkaline earth aluminates, a~d Portland cement; a wax asphalt emulsion prepared by adding to a blend o~ molten wax and asphalt an oil-soluble, water~
dispersible emulsi~ying agent, and admixing the a~oremen~ioned with a solution of casein which contains, as a dispersing agent, an alkali sulfonate of a polyarylmethylene condensation product.
A preferred material for use in impro~ing the water-resist~nt properties of the gypsum core comprises wax-asphal~
emulsion, species o~ which are available commercially. The 3S wax portion of ~he~emuls}on is preferably a paraffin or micro crys~alline~wax, but other WaXe5 can be used also. The asphalt in gene~al~sh~u~d-hav~ a~soPten~ng point o~ abo~ 115~, as '' ' : - - ~ ' ' ' 3~9~31 1~
determined by the ring an~-ball method. The total amount of wax and asphalt in the aqueous emulsion will generally comprise about 50 to ~0 wt.% o~ the a~ueo~ls emul~ion, with the weight ratio o~ asphalt to wax varying from about 1 to 1 to about 10 to l. Various methods are known for preparing the wax-asphalt emulsion, as reported in U.S. Patent No. 3,935,021 to D.R. Greve and E.D. O!Neill, assigned to the same assignee as the present invention. Commercially availabla wax asphalt emulsions that can be used in the composition of the present invention are sold by United States Gypsum Co. ~W~x ~mulsion~, Monsey Products, (No. 52 Emulsion) and Douglas Qil Co. (Docal No. 1034). The amount of wax-a~phalt emulsion used can be within the range of about 3 to about 10 wt.%, preferably about 5 to about 7 wt.~, pased on the.total weight of the ingredient~ of the ccmposition fro~ which the set gypsum core is made, said ingred~ent~ i~cluding the water of the wax~
asphalt emulsion, but not lncluding additional amounts o~
water that are added to the gyp~u~ composition for forming an aqueous slurry thereof.
A partirularly preferred material for use in improving the water-resistan~ prop~rties of the gypsum core comprises a mixture o~ materials, namely, pcly(vinyl alcohol) and wax-asphalt emulsion of the aforeme~tioned type. The use of such additive~ to improve the water resistance oP gypsum product~ is described in aforementioned U.S. Patent No.
3,935,021. . . . .
The source of the poly(vinyl alcohol) is preferably . a substantially completely hydrolyzed form of poly(vin~l ac~tate),..that is, about 97 to 100% hydrolyzed polyvinyl acetat~.~ The poly(vinyl alcohol) should be cold-water insoluble and soluble in water at elevated temperatures,.~or example, at temperatures of about 140 to about 2QSF. T~ -general, a 4 wt.% water solution of poly(~inyl alcohol) at 20C
will have a viscosity of about 25 to 70 cp as determined by means of tha Ho~ppler- ~alling ball method. Commercially 8 3 ~
.
available poly(vinyl alcohols) for use in the composition of the present invention are availa~le from E. I. du Pont de Nemours and Company, sold under the trademark ~Elvanol" and from Monsanto co., sold under the trademark "Gelvatoln~
Examples of such products are Elvanol, Grades 71-30, 72-60, and 70-05, and Gelvatol, Grades 1-90, 3-91, 1-60, and 3-60.
Air Products Corp. also s~lls the product as WS-42.
The amounts of poly(vinyl alcohol~ and wax-asphalt emulsion used should be at least about 0.05 wt. % and about 2 wt. % respectively. The preferred amounts of poly(vinyl alcohol) and wax-asphalt emulsion are about 0.15 to about 0.4 wt. % and about 3.0 to about 5.0 wt. % respectively. Unless stated otherwise, the term ~wt. %n when used herein and in the claims means weight percent based on the total weight of the ingredients of the composition from which the set gypsum core is made, said ingredients including the water o~ the wax-asphalt emulsion, but not including additional amounts of water that are added to the gypsum composition for forming an aqueous slurry thereof.
An attractive feature of the present invention i5 that the ~ibrous mat-faced gypsum support member can be made utilizing existing wallboard manufacturing lines, for example, as shown somewhat diagrammatically in Figure 1. In ~onventional fashion, dry ingredients (not shown) ~rom which the gyp~um core is ~ormed are pre-mixed and then fed to a mixer of the type commonly referred to as a pin mixer 2.
Water and other liquid constituents (not shown) used in making the core are metered into the pin mixer 2 where they ~re combined with the dry ingredients to form an aqueous gypsum slurry. Foam is ~enera~ly-added to the slurry în the pin mixer to control the density of the resulting corer The slurry 4 is dispersed through one or more outlets at the bottom of the mixer 2 onto a moving sheet of fibrous mat 6.
The shee~ o~ ~ibrous mat 6 is in~è~inite in length and is ~ed from a roll (not s~own) of the ma~. ~
3 ~
As is common practice in the manufacture of conven-tional paper-faced gypsum board, the two opposite edge portions of the fîbrous mat 6 are progressively flexed upwardly from the mean plane of the mat 6 and then turned inwardly at the margins as to provide coverings for the edqes of the resulting board 40. In Figure 1, this progressive flexing and shapim~ of the edges o~ the mat 6 are shown for only one side edge of the mat and the conventional guiding devices which are ordinarily employed for this purpose are omitted from the ~igure for the sake of clarity. Figure 7 shows an edge of the set gypsum core 42 covered by the overlapped edge portion 6A of the mat 6. Figure 7 shows also score marks 10 and lOA of the mat 6, the score marks permitting the formation of good edges and flat surfaces. The score marks 10 and lOA are mad~ by a conventional scoring wheel 12. An advantage of using the preferred form of glass fiber mat is that it is capable of being scored and edged like conventional paper facing.
Another sheet o~ fibrous mat 16 is fed from a roll (not shown) onto the top of the slurry 4, ther~by sandwiching the slurry between the two moving fibrous mats which form the facing~ of the set gypsum core 42 which is formed ~rom the slurry. The mat~ 6 and 16 with the slurry 4 sandwiched there-between enter the nip between the upper and lower forming or shaping rolls 18 and 20, and are thereafter received on a conveyer belt 22. Conventional edge guiding devices, such as indicated at 24 shape and maintain the edges of the composite until the gypsum has set sufficientl~ to reta~n i~ s~ape. In 3.0 du~c~ursa,- seguential lengths o~ the b4ar~ ar.e c~t ~nd ~urthe~ prQcessed by exposure to heat which accelerate the drying o~. th~ board by increasing the rate of evaporation o~
excess water in the gyps~.slurry.
. . . . . ..
. . Wlth reference to Fi~e 7.,.it has been observed .
that ths set ~ypsum o~,*he cor~ ~2 is.~ective in formin~
309~31 satisfactory bonds with the mats and between the edge portions of the overlying mat 16 and the overlapped edge portion 6A.o~
the underlying mat 6, thus making it unnecessary to use a bond improver in th~ slurry or an edge paste to form th~
aforementioned bonds.
The preferred form of mats 6 and 16, as shown in Figures 2 and 3, comprises glass fiber filaments 30 oriented in random pattern and bound together with a resin bind~r (not shown).
A preferred form of glass fiber mat-faced yypsum board 40 is shown in Figures 4 and 7. ~t comprises one in which the set gypsum of the core 42 penetra~e~ substantially through the thickness of the mat 6 over substantial aFea portions thereof and in which the set gypsum or the core ~2 penetrates the mat 16 partially, with the suEfa~e being thus substantially free of set gypsum. ~he gypsum-free surface of mat 16, as seen in Fiqure 8, is highly textured, and provides an excellent substrate for adhering thereto an overlying component inasmuch as it comprises many interstices into which an adhesive composition can flow and bond.
In shipping ~ypsum board, it is convenient to package two boards 40 and 40A together (see Figure 10 and 11), with the glass ~iber gypsum-free surfaces 41 and 41A in face to face relationship, and thus protected, and with the gypsum-coated surfaces (for example, 43A in Fiqure 11) forming ~.he outside of the package. The set gyp~um on ~he outside surfaces helps to keep the board from being damaged during handling, shipping and storage, and protects the skin of those who come in contact with`~ è board ~rom being irritated by the glass fibers of the mat.
The phrase ~substantially penetrated hy set gypsumn, as used herein, means that-the set gypsum of the core~ extends fro~`th~ ma~ sur~ace which is con~i~uous to the core to the . - . . . :
23 60382-1~68E
outer mat surface and coats glass flbers on the outer surface with a thin film of set gypsum to the e~tent that the outline of glass flber~ can be ~een through the thin fllm of set gypsum. The phrase "over substantlal area portions of the outer surface", as used hereln, means that about 30 to about 75% of the outer surface area of the mat is substantially penetrated by set gypsum.
Preferably, about 45 to about 55% of the outer surface area of the mat is substantlally panetrated by set gypsum. Accordlngly, the gypsum-coated surface of thls preferred embodiment of the board comprlses a surface that has a roughened or patterned appearance~
it does not comprlse a smooth continuous coating oE ~et ~ypsum.
Thls preferred form of board can be ~ormed with relatively small amounts of gypsum slurry being deposlted on the underlylng support surface, thus mlnimizing the need to clean the surface.
The need for such cleanlng can be substantlally avolded by ad~usting the viscosity of the slurry so that it penetrates but part-way through the underlying fibrous mat, for example, up to about 50% of lts thlckness. Thus, this preferred form of board has to gypsum-free fiber-faced surfaces.
The manufacture of the aforementioned preferred forms o~
board can be accomplished by controlllng the v1scosity of the aqueous slurry of the calcined gypsum in a manner such that the slurry penetrates the underlying and overlylng mats to the de~lred degree. In manufacturlng each of the a~orementioned preferred forms of board the viscosity of the slurry should be such that it penetrates about lO to 50% of the thlckness of the overlying mat over the entire surface thereof.
The recommended means ~or controlling the vlscosity of ~3~g~31 24 6~382--126 the slurry ls to a~d thereto a vi~coslty-control agent. Such vlscoslty-control agents are known in the field of gypsum board manufacture. A preferred vlscoslty-control agent is paper flber.
~xamples of other agents that can be used are celluloslc thickeners, bentonite clays and starches.
The particular viscosity values that are used in ~he manufacturlng operation can vary from one appllcation to the next, dependlng on the poroslty of the mat, and the desired penetratlon of the slurry. Accordingly, for any partlcular appllcatlon, the vlscoslty value ls best determined empirlcally.
In using the preferred form o~ glass fiher mat, as descri~ed above, to manufacture the aforementioned preferred ~orms of board, developmental work has shown that satisfactory results can be achleved utllizing a gypsum slurry having a viscosity wlthln the range of about 5000 to 70Q0 cp. As used hereln, the vlscoslty value refers to Brookfleld viscoslty measured ak a temperature of 70F at 10 rpm utlllzing paddle No. 3. It should be appreclated that the amount of vlscoslty-control agent added to the slurry to glve the desired vlscoslty wlll vary dependlng on the partlcular agent used and the speclfic vlsco~lty deslred.
In preferred form, the core of the ~lbrous mat-faced gypsum board has a denslty of about 40 to about 50 lbs/cublc ft., most preferably about 42 to about 45 lbs/cublc ft. The manu-facture of cores havlng densltles wlthln the preferred range can be ef~ected by using known techniques, for example, by introducing an approprlate amount o~ ~oam into ~he aqueous gypsum slurry ~rom which the core i8 formed. There ar~ welght advantages tha~ can be reallzed by the use of flbrous matfaced gypsum board ln EISystems , ~, ~3~ 3~
24a 60382-1268E
ln that fibrous mats which are lighter in weight than conventional paper facing are available. Eor example, the welght of a widely used paper facing in the manufacture of conventional gypsum sheathlng ls ln the range of about 120 lbs~1000 sq. ~t. of board, whereas the weight of a preferred form of glass flber mat for use ln the . _ ~3~83 ~
present invention is about 40 lbs/1000 sq. ~t. of board.
Turning now to Figures 12 and 13, there is shown therein an example of an exterior insulating sys~em fabrica~ed in accordance with the present invention and comprising the exterior portion of the building 81. The EISystem 80 comprises panels of ~ibrous mat-faced board 82 affixed by nails 84 to wood framing 86. A foamed polystyrene panel 88, about 1 inch thick, i5 adhered to the fibrous mat-faced board 82 by adhesive 90. A rein~orcing member comprising glass fiber scrim 92 is sandwiched between the polystyrene panel 88 and the ~inal finishing material 94 by adhesive 96.
Various o~ the preferred forms o the gypsum board of the present invent~on can be used also to good advantage in place of conventional qyp~um sheathing in applications other than EISystems. Thus, the preferred forms of board can be used as an underlying suppor~ surfac~ which is coversd with overlying finishing materials, for example, aluminum, wood siding, plaster and Portland cement stucco.
EX~MPLES
The ~ormulation set forth below is an example o~ a : 25 preferred a~ueous gypsu~ slurry which can be used in making the core of a gypsum support member in accordance with the : present invention.
Consti~ent~ Lb8. ~1000 sq.~t. of b~oard calcined gypsum 1380 ( aS0-1/2 H20) wax/asphalk emulsion 130 aqueous solution o~ lO w~.%
polytvinyl alcohol) 56 paper ~iber 15 35 set accelerator 6 ammonium lauryl sulfonate (foaming agent) calcium li~nosulfonate (dispersing agent) 2 water 260 ;
~9~31 The wax/asphalt emulsion used in the above formulation contained approximately 48 wt.% ~olids of which about 11 wt.%
was paraffin wax and-about 37 wt.% was asphalt. The set accelerator comprised about 80 wt.% potash, about 12 wt.%
lignosulfonate and about 8 wt.% ground yypsum.
The above formulation was used to prepare gypsum board, the surfaces of which were covered with nonwoven fiber glass mat. The mat was composed of glass fiber filaments oriented in a random pattern bonded together by an adhesive referred to by the manufacturer as a ~modified urea-formaldehyde resin~. The mat had a thickness of 33 mils, was more porous than paper of the type used as the cover sheet of .. . .... . .
gypsum wallbQard,,and was not significantly weakened by water, The air permeability of the mat was 700 CFM/sq. ~t. (test method FG 436-91~. The mat is available commercially as DURA-GLASS 7502-~ lbs. and is an example of a preferred fibrous mat for Use in the practice of the present invention.
Continuous length board was made from the above gypsum slurry and gla s fiber mat on a conventional wallboard machine. The slurry wa~ ~ed onto a moving sheet of the mat as it was unrolled from a roll onto a moving support sur~ace.
The mat had a width of about 51 inches and was scored continuously by con~entional scoring blades prior to the depo~ition o~ the ~lurry thereon. Each edge of the mat was scored with ~wo score marks, with each of the outer score~
b~ing about 1 inch from its respective edge of the mat-and:
each o~ the inner scores being about 1 1/2 inch ~rom its re~pective edge. After the slurry Was deposited-on the mat, the edges were folded at the score marks and overlapped on top of the slurry. (The gypsum core formed ~rom this opëration ' had a width of 47 7/8 inches and a thicknes~ of 1j2 inch.) Mat from another roll thereof and having a width of 47 1/2 inches was fed onto the top of the gypsum slurry and the overlapped edge portion~ of the underlying mat. The gypsum 3~831 slurry penetrated the overlapped edge portions and served to bo~d t~e edge portions of the overlying mat to the overlapped edge portions o~ the underlying mat.
The viscosity of the gypsum slurry was about 5900 cp at 70F. At this viscosity, the slurry penetrated substantially throu~h some portions of the underlying mat to form a thin film thereof on about 40 to 50% of the area o~ the outer surface of the mat. As the gypsum in ~he film set, substantial portions of the outer surface of the mat were covered with a thin film of set gypsum. The surface had a roughened appearance with outlines of the glass filaments bei~g observable underneath the thin coatings of gypsum which covered them. However, at the aforementioned viscosity, the s}urry penetrated but a portion (about 5 mils) of the thicknesq o~ tha overlying mat oYer the entire area thereof, with no ~lurry being observed on the outer surface of the mat.
A~ the gypsum 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 gypsum cors.
The continuous length board is cut into lengths of about 8 feet. Drying o~ the gypsum board is accelerated by heating in an oven at 350F for about 2 hours and until the board is almo~t dry and then at 200F for about 1 hour until it i~ dried completely. The density o~ the board is about 43 lb.
cu.ft.
Th~ gypsum-free surfaces o~ panels (2' X 2') oP
glass fibër-f~ced board as described above were adhered to panels o~`expande~ po~'ys~ren~'utill'z`ihg ~wo different commercially a~a~là~lé adhesive sy~tem~. In one system, hereafter ~Sys~ëm A~, on~ of the ~aces o~ a paneI ~f expanded polystyrenë having a thicknë~s of ~o~t I i~ch a~ 2' X ~' was smeared with an adhesive mix~ure comprising cement~, sand, and resin binder u~ilizing a 3/8n X 3~8~ toothed trowel. The panel was then adhered to ~he glas~ fiber-~aced gyp~um board.
. . .~
~3~31 Thereafter, glass fiber reinforcing mesh was applied to the other fa~e of the panel of expanded polystyrene and a decorative finish was applied ~o the mesh.
In the other system, hereafter ~System B", the same steps a described above for System A were followed except that an acrylic adhesive was applied to the gypsu~-free surface of the board and the polystyrene panel adhered thereto.
Two additional systems like Systems A and B above were assembled, except that conventional paper-faced gypsum sheathing wa~ substituted for the glass fiber-~aced gypsum board in each of ~ystems A and ~.
The integrity o~ each of the systems was evaluated using 1 1/2" X 1 1/2~ cross-sectional cubes which were extracted from the systems and which were pulled apart in a tensile test apparatus. The results o~ the testing are set ~orth below.
Fiber Glass- Paper-~y~ Faced Board Faced Board A 100~ break in 66% break in the the polystyrene paper, 33% break panel in the polystyrene B 100% break in 100% break in the the polystyrene paper panel From t~ above re~ults, it can be ~een that the use of tha glas~ fiber-faced gypsum support surface improved signifi-ca~ly the strength o~ the assembly in that tensile failure wa.~;trans.ferred ~rom the paper cover of ~he gypsu~ ~heathing to ~h~ ~oamed polystyrene, with no failure at all experienced in the glass ~iber mat or the gypsum core to which it wa~
adhered. Thu$~ hould b~ ap~reciated t~t, in accordance wit~ the~present:inYention~ th~ in~ri~y sf an EI~stem ca~
, ... .. ..
13~831 be improved significantly becaus~ it is no longer dependent upon the ply strength of a paper co~er sheet, but upon a component having much higher strength. ~ ~
Glass fiber-faced gypsum boards, made as described above, and with their edges protected, were placed outdoors for several months and exposed to the elements. During that period, the boards were exposed to a~out 20 inches of rain.
After this exposure, the boards were examined and ~ound to be lo in excellent condition with no signs of deterioration~
Other outdoor tests have shown that glass fiber mat-faced gypsum board in accardance with the presen~ invention and having a core which includes wax-asphalt emulsion as a water-resistant a~ditive better resists deterioration than a like board having a core which in~ludes``sodium methyl siliconata as the water-resistant additiY~.;
\ Gy~sum board comprising a set gypsum core faced with 20¦ a fibrous mat, as described herein, and pr~erably gypsum i board comprising a set gypsum core sandwiched between two sheets of porous glass mat, can be used to particular advanta~e also a~ a component of a shaft wall assembly or similar asse~bly in the interior of a building. In such application, the fibrous mat-~aced board can be us~d to particular ad~antage in place o~ conventional paper-faced gypsum core board or shaft liner pane}s~ the core o~ which generally include~ fire-resistant additive~. Assemblies of this type g~nerally comprise metal framework or studs for support o~ th~ gypsum panels which ~orm ~ha wa~ls of the shafts of elevators~ stairwells and the lika. Example o~
such assemblies are shown in U.S. Patent Nos. 4,047,355;
4,324,0B2 and 4~364,212. Fibrous mat-~aced board~ as described hsrein, can be used, for example, in the a~semblies described in th~ aforementioned patents, and particularly as the shaft liner panel. For use in such application, th core of th~ board can include fixe resistant additives.
30 ~L3~983~
In summary, it can be said that the present invention provides in a practical way important functional improvements in exterior finishing systems for buildings, including particularly exterior insulating systems, and in shaft wall assemblies.
;, , ' .
FIBROUS MAT-FACED GYPSUM BOARD
Field of the Invention-This invention relates to improvements in exterior ~inishing systems such as, for example, exterior insulation syste~s for buildings, and also to improvements in shaft wall assemblies for buildings. More particularly, ~his invention relates to an improved structural component ~or us~ as a support sur~aca in an exterior finishin~ system, including an exterior insulation sy~tem (sometimes referred to herein for .
convenience as ~EISystem). In addition, the present invention encompasses improvement~ in hollow shaft wall a~semblies, ~or example, those used in constructing elevator sha~ts and stairwells.
~his invention will be described initially in connection with its use in EISystems, but, as will be explained hereinafter, its use has wider applicability.
EISystems are presently being used more and more widely to insulate existing buildings and buildings under construction including indus~rial, oommercial, municipal, in~titutional, and residen~ial buildings. ~ns~allation o~ a typical EISystem in new construction generally involves the , - 13~1~83~
following sequential steps: (A) constructing a frame ~or support of the outside wall of a building; (B~ affixing to the frame structural panels to provide a smooth continuous surface for the support of other of the components of the EISystem; (C) affixing to the support sur~ace panels o~
insulation; and (D) affixing to the panels of insulation a mesh-like material which in turn is covered with an exterior finishing material having weathering and aesthetic properties.
Such systems are designed to be not only highly insulative in character and attractive in appearance, but also waather resistant. EISystems can be used to advantage to conserve energy used for heating and to conserve energy used for air-conditioning.
EI5ystems have inherent advantages over interior insulating systems and, in addition, they can be used to better advantage than interior insulating sys~ems in many applications.
For example, ~he range of temperature variation in structural components comprising the walls of a building insulated from the outside is less than that for such components in a building which is insulat~d from the inside.
Accordingly, such structural components when insulated ~rom the outside are subjected to siynificantly lower amounts of stress caused by thermal expansion and contraction than those insulated ~rom the insideO This is particularly advantageous in applicationY where the structural componenks comprise materials having markedly different co f~iciants of expansion, as is often the case. In addition, the interior space in a building having an EISystem tends to have a more uniform temperature and be less drafty than that o~ a building insulated ~rom the inside.
Certain buildings are not capable o~ being insulated from the interior except that valuable inside space is los~ ~o the system. The installation of an EISystem does not dlsturb "` 130983~
the inside space of the building.
An EISystem can be used also to mo~ernize or otherwise renovate the exterior of a ~uilding in nee~ of renovation. Various of the EISystems which are-commercially available give the architect a wide range of aesthetically pleasing designs from which to choose. In addition, the oost of installing an EISystem is relatively low when there is taken into account both the costs of othar systems and the improved thermal efficiencies that can be realized. The relatively light weight of both the insulation and the exterior finish in an EISystem i5 particularly ~dvantageous in new construction because of reduced foundation requirements.
Th~re are, howev~r, problem~ associatad with the design and/or installation o~ EISystems. As will be discussed in detail below, various o~ th~ problems stem from ~he type of material which is used as t~e supporting member for the insulating and exterior finishing materials of the system.
The pre~ent invention involves improvements in such suppor~ing member.
Reported DeveloPments As mentioned a~ove, a typical EISystem includes a supporting member to which there is affixed insulating material, which in turn is covered with an exterior ~inishing material. An exemplary EISystem includes a wood or m~tal fram2 which i mechanically held in place by nails or screws to appropriate structural members o~ the building, with panels of the supporting member in turn mechanically affixed by natls or screws to the frame. The supporting member, which typically consists of a smooth continuous surface comprising individual panels of material positioned in abutting relationship, must be strong enough to carry tha we~ght of the components which overlie it, including the insulatin~ and exterior finishing materials Although low density, light ~, ' 13~831 weight insulating pan~ls of expanded polystyrene are used widely in such systems, the exterior finishing material i5 yen~rally a much denser and heavier weight material, for ëXa~pl~ n acrylic resin/cement coating that may include *ec~rative aggregate embedded therein.
Certain of the commercialized EISystems include the use of panels of a Portland cement-based composition as the structural member for the support of the overlying panels of insulation and exterior finishing material. It is believed that such cement-based panels are described in U.S. Patent No.
3,284,980 which discloses a building panel comprising a core consisting of a mixture of hydraulic cement and light-weight aggregate (for example, perlite) sandwiched between sheets of ~ibrous material (for example, woven glass fiber screen), which are adhered to the faces of the core by separate layers o~ bonding material containing at least 50% hydraulic cement.
Although 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 weigh~ about 40 1/2 po~nds. The handling and installation of such panels lead to the consumption of relatively large amounts o~ energy. This is a burden to workmen and makes ~ransportation o~ the panels relatively costly.
.
A material which is used more widely in EISystems than the a~orementioned cement board is gypsum board, ~ha~ is, panels co~prising a core of set gypsum (calcium sulfate dihydrate) ~andwic~ed between paper cover sheets. The particular typë o~ gypsum board that is recommended for use in EISystems is known as-~gypsum sneathing~ which is gypsum board designed for use on the exterior o~ ~uildings where it serves as an underlying sur~ce wnich is covered wi~n~uc~ m~terials as aluminum, wo~d si~ ;'Portlan~'ceme~t"s~c~ aA~ n the cas~ o~!an-~ISys~em,-with insu~at'ing'an~`extërior fln"ishlng materials. C~nv~ntion~'l gypsùm sheathing, as opposed to conventional gypsum wàll~oard for use in th~ interior o~ a 30~8~1 building, includes a set gypsum core which contains one or more additives which improve the water resistance of the set core. The gypsum core o~ commercially available wallboard can absorb as much as 40-50 wt.% water when immersed ther in at a temperature of 70F. for about 2 hours. As the absorption of water tends to substantially reduce the strength of the core, materials which reduce the tendency o~ the core to absorb water are included therein. In addition, sheathing has water-repellant paper cover sheets which shed water. This is temporary protection for the sheathing before it i5 installed and before it is covered with the exterior finishing material.
Gypsum sheathing has many desirable characteristics which make it suitable for use in an EISystem. For example, such sheathing has relatively good fire-resistant properties, it is relatively li~ht in weight, it has satisfactory water-resistant properties and it can be mechanically affixed in convenient fashion to a metal or wooden frame which underlies the sheathing.
Notwithstanding the aforementioned, concerns have been expressed respecting the use of such gypsum sheathiny in EISystems. By way of background, it is noted that it is conventional in the industry to affix panels of insulating material to the underlying support of gypsum sheathing by the use of an adhesive material and, in turn, to af~ix by the use of adhesive material~ each o~ the plies which overlie the panels of inisulation. Except for the use of mechanical fastening meani~ in the construction of the frame of the building and in affixing the gypsum sheathin~ to the frame, all of the components of the EISystem are in effect glued ~et~e~ ~. .... . , ~ . ... .
.
.. ~ . . . . .... .. . . .
Tests designed to evalua~e the cohesive ~trength of and the a~hesive stre~qths between the various components comprisîng the EISy~tem have show~th~ itial f~ilu~e ~;
`
:
130983~
~pulling apart) of the system occurs not in any of the adhesive layers, but in the paper cover sheet of the gypsum sheathing. Such cover sheet 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 monolithic sheet of paper. Accordingly, the cohesive strength of the paper can be characterized as the we~k portion of the system.
Another concern respecting the use of gypsum sheathing in EISystems of the aforementioned type is tha~
water leakage through the system can lead to the deterioration of the bond between the paper cover sheet and the gypsum core.
(Although the system is designed to be waterproof, there are circumstances where defects in one or more plies o~ the system and/or unusually sev~re environmental condition~ are the cause of water seepage). It should be appreciated that deterioration of thi bond can lead to cracking of tha Pxterior finish, and possibly even collapse o~ portions of the system a~ the component which is adhered to *he paper cover sheet pulls apart.
In an effort to overcome th~ aforementioned type problems, it has been proposed to affix the insulatlng material to the underlying gypsum sheathing by the use of mechanical fasteners which extend through the insulating material, the core of the gypsum sheakhing, and into the frame. This approach to the problem has the disadvantage that the work time involved in installing the system is increased significantly inasmuch as it is much mor~ time consuminq to install fasteners than to apply an adhesive. Another shortcoming of thq fastener approach is that the fasteners provid~ paths for the flow o~ water which may penetrate the ~... .
system and weaken ~he bond between the paper cover shee~ and gypsum core, as mentioned abova.
Irres~ective of how the insulating material is affixed to the underlying gypsum sheathing, there is another problem connected with the use of sheathiny in EISystems.
Because of it5 susceptibility to degradation by water, care must be taken to protect the sheathing from rain and other moisture conditions which may~b~ encountered as the sheathing is stored at the ~ob site awaiting use and during installation. Taking such protective precautions consumes time, causes inconvenience, and sometimes causes delays in installation of the system - all of which tend to increase costs.
Although gypsum sheathing has a water-repellant paper surface which provides some limited protection against water degradation, this type of surface forms a relatively poor bon* with water-based adhesives which are used to adhere to.the.surface other components of the EISystem.
The present invention is a support member; for use in EISystems and sha~t wall assemblies, comprised of an improved gypsum-based structural component which is modified in a manner suc~ that problems of the type associated with the use of conventional gypsum sheeting are either overcome or alleviated significantly.
5~MMARY OF THE I~VENTION
In accordance with the present invention, there i8 provided an improved structural support element comprising a fibrous mat-faced gypsum support surface for use in an exterior finishing system, including exterior insulating systems, for buildings and in shaf~ wall assembliesr one embodiment of the present invention is a gypsum board comprising a set gypsum core sandwiched ketween two sheets of porous glass mat of randomly dist~ibu~ g~ss~hbe~1.bonded by an adhesive material. Each mat has~a~iinner an~ outer surface, the inner surface of which ls adhered t~ ~he.gypsum core by a portion of the set gypsum comprising the core. The ou~er surface of one of the mats has portions coated with the set gypsum o~ the core. The outer surface of the other of the 3~9831 mats is substantially free of set gypsum.
Preferably, the gypsum core has one or more additives which improve the water resistance thereof. As will be seen from examples repoxted below, a structural member comprising a water-resistant gypsum core faced with glass mat, which itself is hydrophobic, has outstanding weathering characteristics.
An additional preferred form of the present invention comprises a gypsum board having each of its core faces covered with a porous glass fiber mat, with the ~at of one of the faces being adhered to the core by ~et gypsum penetra~ing but part-way înto the thickness of the mat and having its outer.surface substantially free of set gypsuml As will be described below, the glass ~iber mat surface, which is free of set gypsum, provides an excellent substrate to which overlying panels of insulation can be adhered.
In one embodiment of the above form of the invention, the out~r sur~ace of the mat of the other corR face i5 also substantially free o~ set gypsum, with set gypsum o~
the core penetrating but part-way into the thickness o~ the mat. As will be described below, there are manufacturing advantages which accompany the production of gypsum board o~
such embodimentO
In another embodim~nt of the aforementioned ~orm o~
the pre~en~ invention, the set gypsum of the core penetrates substantially thr~ugh the.thickness of the mat o~ the other c,ore fac0 o~er.s~bstanti~1.area portions thexeof in amoun.~s which are suf~icien~t~ coa~ gla~s ~i~ers of the mat with.a thin film of s.et-gyps.~, but~not ~ufficient t~ form a smooth, continuou~.~oating o~ se~..gypsum. ThiS embodiment in which signi~icant portions o~ the outer surface of the mat have set gypsum therean provides a protective sur~acQ i~-.a .~wo,~board package in which the~boards.are-packed to-~ether ~i~h the .
---- 130~31 gypsum-~ree surfaces in ~ace-to-face relationship and with the ~ypsum covered faces being exposed. More particularly, this preferred form of board comprises a set gypsum core sandwiched between two adhering sheets o~ porous glass mat of predetermined thickness, each of said mats ha~ing an inner and outer surface and comprising randomly distributed glass fibers bonded by an adhesive material, the inner surface of each of said mats being adhered to said gypsum core, and with set gypsum o~ the core at one sur~ace thereof penetrating substantially through the thickness of one of said mats over subs~antial area portions thereof and coating substantial area portions of the outer surface thereof and with set gypsum of the core at the other surface thereof penetrating but part~way into the thickness of the other of said mats, the outer surface of the other o~ said mats being substantially free of~
set gypsum.
Still another aspect o~ the present invention comprises a process for making the aforementioned embodiments 2Q o~ gypsum board, that is, the embodiment in which bokh outer sur~aces of the mats ars substantially free of set gypsum and the embodiment in which the outer sur~ace of one of the mats is substantially ~ree of set gyp~um and that of the other mat has set gypsum thereon. The proce~s includ~s known steps used heretofore in manufacturing in continuous fashion conventional wallboard and known glas~-fiber mat-faced gypsum board, but di~fers there~rom in that the viscosity of the aqueous gypsum slurry from which the board core is made is controlled in a manner such that the slurry penetrates into the mats to the extent needed to~achieyç the desired result. .The basic steps of the proc~s comp~is~
. . .
(A) forming an aqueous slurry of calcined qyp~um;
(B) continuously feeding said aqueous slurry on~o an underlying, moving and supported porous fiber glass mat having a predetermihed thickne~s and an outer surface;
.(Cl forming said deposited~slurry a~ it i~ carried ' .
309~31 on said moving mat into~-a panel-like shapa; and (D) applying to the~top surface o~ said panel like shape of ~lurry an overIying porous f~ber glass ma~ of predetermined thickness. ; - : ~ -. ~
In forming gypsum boaxd in which ~oth of the outer mat surfaces are substantially ~ypsum-free, the viscosity of the slurry is maintained at a value such that portions of said slurry penetrate but part-way through the thickness of each of said underlying and overlying mats and the panel-like shape of slurry is maintained a~ the calcined gypsum sets to form a set gypsum core having adhered to its surfaces the und~rlying and overlying fibQr glass mats.
: .
In ~arming the gypsum-coated/gypsum-~ree form of glass fiber-~aced board, the viscosity of the slurry is maintained at a valu~ such tha~ portîons of said slurry penetrate substantially through the thickness of said underlying m~ over substantial area portions thereof to coat substantial area portions of the outer surface and at a valu~
such that portions o~ said slurry penetrate but part-way into the thickness of said overlying mat.
There are numerous advantages whi~h flow from the use of the present inven~ion. ~n EISystem which includes a fibrou mat-faced gyp~um support surfa~e that has affixed thereto in~ulating mat~rial hy adhesive only, that i , without fastening means which extend through the insulating material, has higher tensile or cohesive strength than a like sys~am which includes convantional paper-faced ~ypsum bo~rd. Testing of systems of ~his invention which include insulatio~ ih the form of expanded polystyrene panels has ~hown that lnitial failure is experienced by a pulling apart o~ th~ ex`pan~ed polystyrene panel, thus evidencing improvement in ~réng~h relative to conventional systems where initial faiiure is experienced in the paper plies of the g~psum support mem~ér.
The fibrous mat-faced surface of the gypsum support member i~
30~83~
water resistant in contrast to conventional paper cover sheets of gypsum board which can soak up water. This improved water resistance gives the applicator greater flexibility in selecting adhesives that can be used to adhare insulation directly to the mat-faced surface of the gypsum support element as adverse affects are not encountered by the use of water-based adhesives. The fibrous mat-faced surface of the gypsum support element is ~nailable~, and accordingly, it can be secured readily to an underlying frame or other substrate by nailing. In comparison to various of the commercially available systems, the improved support surface of the present invention has improved rigidity and strength uniformity in both the length and width dimensions of the system. Unlike conventional paper cover sheets, the fibrous mat does not expand or contract during the manufacture of the product; this reduces cockle and leads to uniformity of dimensions. The preferred embodiment of the invention which includes the use of a water-resistant core provides a substantially improved weather-resist~nt product which better re~ists degradation both within and outside of the system.
Figure 1 is a somewhat diagrammatic, fragmentary side elevational view illustrating portions of a manufacturing line for producing gypsum board of a type sui~able ~or use in the manu~acture o~ gypsum board prepared for use in accordanca with the present invention;
. .. . . . . .. . ... . ... .
Figur0 2 i~ an enlarged fragmentary sectional view, taken as indicated toward the lè~t of ~igure 1, of an underlying fiber glass mat used in the manufacture of the gypsum board;
.. . .. .. . . ... . ... .
Figure 3 is a fragmentary plan view taXen as indicat~d by the line 3-3 on Figure 2;
.. , ~,. .. . .
~.3~983~
Figure 4 is an enlarged sectional view taken as indi~ated toward the right on Figure 1 and illustrating both underlying and overlying fiber glass mats, with intervening gypsum composition, used in the manufacture of the board;
Figure 5 is a fragmentary plan view taken as indicated by line 5-5 on Figure 4:
Figure 6 is a fragmentary bottom view taken as indicated by the line 6-6 on Figure 4 and illustrating the bottom surface of the underlying mat of the board;
Figure 7 is a transverse sectional view o~ an edge portion of the completed board, this view being taken as indicated by the line 7-7 on Figure 4;
Figure 8 is a further enlarged fragmenta.ry sectional view taken as indicated toward the top of Figure 4;
Figure--9 is a further enlarged fragmentary sectional view taken as indicated toward the bottom o~ Pigure 4;
Figure 10 is a view illustrating two complete gypsum boards fabricated according to the present invention and being assembled for packaging, with the top fibrous mats of the two boards presented toward each other;
Figure 11 is a view of two hoards assembled in th~
manner indicated in Figure 10 and bound together ~or purpos~s of shipping:
Figure 12 is a somewhat dia~rammatic ve~tical sectional view through the upper portion of an external building wall, a~ insulated in accordanca wi~h the presen~
invention; and .
~3~83~
Figure 13 is an enlarged vertical sectional view taken substantially as indicated on Figure 12.
DETAILED DESCRIP~ION OF THE`INVENTION .-The essential components of an EISystem comprise insulating material which is sandwiched between an underlying support surface and an exterior finishing material which can be an integral part of the insulating ma~erial, ~u~ which is usually applied to the insulating material at the site o~
installation. From one EISystem to the next, there exist variations in structural details and components. For example, although the exterior finishing material may be a~fixed directly to the insulating material, various systems include a reinforcing compo~ent sandwiched between the exterior finishing material and the insulating material. The reinforcing component comprises generally one or mor~ plies of fiber glass reinforcing fabric or mesh which is adhered by suitable mastic to the sur~ace of the insulating material. In some systems, the support surfa~e is affixed to a wooden ~rame attached to the exterior surface of the outside wall of a building, whereas in other systems a metal frame is used. In certain applications, the support sur~ace may be affixed dixectly to the ext~rior surface of an outside wall, ~or example, sne comprising cinder blocks or concrete bloc~s. In new construction, the support sur~ace is typically af~ixed directly to the frame of the building. The adhesive or mastic for adhering together componants o~ th~ system tend~ to vary from one system to the next, and typically comprises specially formulated proprietary compositions. The improved support surface of the present invention can be used satisfactorily and to good advanta~e in EISystems which include overlying plies o~ insulating and exterior finishing materials~ and other optional components.
Presently, the most popularly used insulating material in EISystems is expanded or foamed polystyrene, a .
. . .
13~9~3~
material which has good moisture re~istant properties.
Although it has desirably low water vapor transmission, it is not a vapor barrier, but instead is capable of breathing.
Rigid panels of expanded polystyrene are used most widely in EISystems. Such panels have satisfactory compressive strength and resilience and are presently available in thicknesses ranging ~rom 1/2 to 6 inches, widths from 6 to 48 inches and lengths ranging from 4 feet to 16 feet~ One commercially available system utilizes rigid, expanded polystyrene panels which are 2' X 4' X 1~.
other thermal insulating materials can be used in EISystems also. Examples of such materials include extruded polystyrene, polyurethane, isocyanurate, cement-based insulating plaster~, and phenolic foam. Insulating materials generally h~ve low thermal conducting and low density.
As mentioned above, various EISystems include a reinforcing component, for example, in cloth form, sandwiched between the insulating material and the exterior ~inishing material. Glass cloth is most widely used at the present time to reinforce the system, that is, to improve the impact strength of the s~stem. The particular type or types of glass cloth used and the number o~ plies thereof which are used depend on the impact resistance which is desired. Examples o~
reinforcing cloth or fabric which can be used in the system are woven glass, glass fib~r scrim and glass fiber mesh.
Installation of the reinforcing fabrir generally involves applying a suitable adhesive to the surface of the insulating material and then applying the fabric tAere~o. Additional plies of fabric can be applied if desired. A cement/acrylic resin is an example of an adhesive that can be used..
......... ... ... ..
The exterior ~inishing material can be affixed directly to the insulating material or to an in~ermediate surface such as, for exa~ple, the surfac~ Qf a reinfurcing member as described ab~ve. The exte~ior inishing material 983:1 has weathering characteristics and is preferably appealing in appearance. Presently, the most widely used exterior finish i5 an acrylic resin-based composition which is available in a paste-type fo~m which is spread or troweled on the underlying substrate. One type of such composition can be described as a ready-mixed synthetic resin plaster. Afte~ application, the resin sets to ~orm a tough~ weather-resistant solid material which adheres tightly to the underlying substrate. Such resin compo~itions are available commercially in a variety of colors. They include optionally aggregate which can vary in size. This allows the applicator to choose a particular composition which permits him to apply a finish that can vary in texture from fine to coarse. Finishes which have a stuoco-like appearance are popular. Small stones of various colors can be embedded in the composition ~or decorative purposes.
Examples of other materials that can be used as an exterior finish are Portland cement stucco including, for example, sand and larger aggregats.
The exterior finish can vary in thickness over a wide range, with a thickne s of about 1/16~ to about 1/4 being exemplary.
Turning now to a description of the improved support member for use in exterior systems of the present invention, it comprises a set gypsum core ~aced with a fibrous mat. The gypsum core is basically of the type used in those gypsum structural products which are known as gypsum wallboard, dry wal}, gyRs,um board and gypsum sheathing. The ~GO~ o~such a pr~duct is ~rmed by mixing water wi~h pow~red anhydrous calcium sul~ate or calcium sulfate hemihydrata (CaSO4;1/2H20), alsa known a~ cal~ined gypsum, and therea~ter allowing the mixture to hydrate or set into cal~ium sulfate dihydra~e (CaS04 2H20), a rela~ively hard material~ Tha car~ of the support member will in general ~omprise ~t ~east ~bout 85 wt.
percen~ set gyps~m. ~: ~
.
- - :, ~3~83~
, The composition from which the set gypsum core is made can include optional constituents, including, for example~ those included conventionally in gypsum shea~hingO
Examples of such constituents include set accelerators, foaming agents, and dispersing agents. As will be described in more detail below, a preferred gypsum core ~or use in the present invention includes one or more additives which improve the water resistant properties of the core.
The surface of the core to which the insulating material of the system is affixed is faced wi~h a fibrous mat.
The fibrous mat should be sufficiently porous to permit water in the aqueous gypsum slurry from which the gypsum core is made to evaporate therethrough. As described in de~ai~ beiow, lS the gypsum support element for use in the present inv~tion can be made ef~iciently by forming an aqueous gypsum s~urry which contains excess water and placing thereon the fibrous mat. Aided by heating, excess water ~vaporates ~hrough the porous mat as the calcined gypsum sets~
The ~ibrous mat comprises material which is capable of forming a strong bond with the set gypsu~ compri-~ing the core of the suppor~ sur~ace. Examples o~ such materials include a mineral-type material such as glass ~ibers and synthetic resin fibers. The mat can comprise con~.inuous or discrete strands or ~ibers and be woven or nonwoven in form.
Nonwoven mats such as chopped strand mat and continuous strand mat can bP used satis~actorily and are less costly than woven materials. ~he strands of such mats are konded together hy suitable adhesive. The mat can range in thickness, for example, from ~bout~ t~ about 40~mils, ~ith a ~hickness o~
about 25 to about 35 mil-s being pr~ferred. The aforementioned fibrous mats are known and are commercially available in many formS. . ..
, ~ ... . ... .. . . . . .. .. . .
T~ pre~erre~ rou~ ma~ is a ~iber glass mat 30983~
comprislng flber glasa filaments oriented in random pattern and bound together with a- res~n bind~r. Plb~r glass mats of this type . . .
are commercially available, for example, those sold under the trademark DURA~GLASS by Manville Bullding Materials Corporation and those sold by ELK Corpora~ion as BUR or shingle mat.
Although improvements ln an EISystem can be realized by the use of a gypsum core which has but one of it8 surfaces faced with flbrous ma~ as descrlbed herein, lt is preferred that both sur~aces of the core be faced with substan~ially the ~ame f~brous màterial. If the surfaces of the core are faced with materials that have differqn~ coefficlent~ of expansion, the core tends to warp. Flbrous mat-face`d gypsum board and methods for making the same are known, for example, as described in Canadian Patent No.
993,779 and United State~ Patent No. 3,993,822.
As mentioned above, the preferred form of the fibrous mat-faced gypsum support surface comprises a gypsum core which has water-resistant properties. The preferred means for imparting water-reslstant properties to the gypsum core is to lnclude in the gypsum composltion from whlch the core ls made one or more additiveq which lmprove the ability of the set gypsum compositlon to resist beinq dagraded by water, for exam~le, to r~si3t dissolu-tion. In preferred form, the water xeslstance of the core is such that it absorbs less than 5 percent water when tested.in. ..
accordance with ASTM method C~473.
The fibrous mat for use in the present invention has substantially better water-rasls~ant properti~s ~han ~he conventiona.l paper facing of gypsum wallboar`d or sheathing.
.,. . - . , , ~ . . .
::
~L3~9~31 Nevertheless, evaluations have shown that the bond between the fibrous mat and gypsum core can deteriorate relatively quickly under the influence of water. For example, samples exposed to the weather showed loosening at the glass fiber facing within .
.: .. :.. .. . . .. -.. , .. : ..
.. : .:
" - :;, 17a .
~30~831 one to two months. In contrast, evaluations o~ water-resistant gypsum core faced with fibrous mat in accordance with the present invention have shown the bond between the mat and core resists being degraded by water for indefinite periods of time.
Examples of materials which have been reported as being effective for improving the water-resistant propertias of gypsum products are the following: poly(vinyl alcohol), with or without a minor amount of poly(vinyl acetate);
metallic resinates; wax or asphalt or mixt~res thereof: a mixture of wax and/or asphalt and also corn~lower and potassium permanqanate; water insoluble thermoplastic organic materials such as petroleum and natural asphalt, coal tar, and thermoplastic synthetic resins such as poly(vinyl acetate), poly(vinyl chloride) and a copolymer of vinyl acetate and ~inyl 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 fonm of an emulsion and either residual ~uel oil, pine tar or coal tar; a mixture comprising residual fuel oil and rosin; aromatic isocyanates and diisocyanates; organohydrogenpolysiloxanes; a wax-asphalt emulsion with or without such materialæ as potassium sulfate, alkali and alkaline earth aluminates, a~d Portland cement; a wax asphalt emulsion prepared by adding to a blend o~ molten wax and asphalt an oil-soluble, water~
dispersible emulsi~ying agent, and admixing the a~oremen~ioned with a solution of casein which contains, as a dispersing agent, an alkali sulfonate of a polyarylmethylene condensation product.
A preferred material for use in impro~ing the water-resist~nt properties of the gypsum core comprises wax-asphal~
emulsion, species o~ which are available commercially. The 3S wax portion of ~he~emuls}on is preferably a paraffin or micro crys~alline~wax, but other WaXe5 can be used also. The asphalt in gene~al~sh~u~d-hav~ a~soPten~ng point o~ abo~ 115~, as '' ' : - - ~ ' ' ' 3~9~31 1~
determined by the ring an~-ball method. The total amount of wax and asphalt in the aqueous emulsion will generally comprise about 50 to ~0 wt.% o~ the a~ueo~ls emul~ion, with the weight ratio o~ asphalt to wax varying from about 1 to 1 to about 10 to l. Various methods are known for preparing the wax-asphalt emulsion, as reported in U.S. Patent No. 3,935,021 to D.R. Greve and E.D. O!Neill, assigned to the same assignee as the present invention. Commercially availabla wax asphalt emulsions that can be used in the composition of the present invention are sold by United States Gypsum Co. ~W~x ~mulsion~, Monsey Products, (No. 52 Emulsion) and Douglas Qil Co. (Docal No. 1034). The amount of wax-a~phalt emulsion used can be within the range of about 3 to about 10 wt.%, preferably about 5 to about 7 wt.~, pased on the.total weight of the ingredient~ of the ccmposition fro~ which the set gypsum core is made, said ingred~ent~ i~cluding the water of the wax~
asphalt emulsion, but not lncluding additional amounts o~
water that are added to the gyp~u~ composition for forming an aqueous slurry thereof.
A partirularly preferred material for use in improving the water-resistan~ prop~rties of the gypsum core comprises a mixture o~ materials, namely, pcly(vinyl alcohol) and wax-asphalt emulsion of the aforeme~tioned type. The use of such additive~ to improve the water resistance oP gypsum product~ is described in aforementioned U.S. Patent No.
3,935,021. . . . .
The source of the poly(vinyl alcohol) is preferably . a substantially completely hydrolyzed form of poly(vin~l ac~tate),..that is, about 97 to 100% hydrolyzed polyvinyl acetat~.~ The poly(vinyl alcohol) should be cold-water insoluble and soluble in water at elevated temperatures,.~or example, at temperatures of about 140 to about 2QSF. T~ -general, a 4 wt.% water solution of poly(~inyl alcohol) at 20C
will have a viscosity of about 25 to 70 cp as determined by means of tha Ho~ppler- ~alling ball method. Commercially 8 3 ~
.
available poly(vinyl alcohols) for use in the composition of the present invention are availa~le from E. I. du Pont de Nemours and Company, sold under the trademark ~Elvanol" and from Monsanto co., sold under the trademark "Gelvatoln~
Examples of such products are Elvanol, Grades 71-30, 72-60, and 70-05, and Gelvatol, Grades 1-90, 3-91, 1-60, and 3-60.
Air Products Corp. also s~lls the product as WS-42.
The amounts of poly(vinyl alcohol~ and wax-asphalt emulsion used should be at least about 0.05 wt. % and about 2 wt. % respectively. The preferred amounts of poly(vinyl alcohol) and wax-asphalt emulsion are about 0.15 to about 0.4 wt. % and about 3.0 to about 5.0 wt. % respectively. Unless stated otherwise, the term ~wt. %n when used herein and in the claims means weight percent based on the total weight of the ingredients of the composition from which the set gypsum core is made, said ingredients including the water o~ the wax-asphalt emulsion, but not including additional amounts of water that are added to the gypsum composition for forming an aqueous slurry thereof.
An attractive feature of the present invention i5 that the ~ibrous mat-faced gypsum support member can be made utilizing existing wallboard manufacturing lines, for example, as shown somewhat diagrammatically in Figure 1. In ~onventional fashion, dry ingredients (not shown) ~rom which the gyp~um core is ~ormed are pre-mixed and then fed to a mixer of the type commonly referred to as a pin mixer 2.
Water and other liquid constituents (not shown) used in making the core are metered into the pin mixer 2 where they ~re combined with the dry ingredients to form an aqueous gypsum slurry. Foam is ~enera~ly-added to the slurry în the pin mixer to control the density of the resulting corer The slurry 4 is dispersed through one or more outlets at the bottom of the mixer 2 onto a moving sheet of fibrous mat 6.
The shee~ o~ ~ibrous mat 6 is in~è~inite in length and is ~ed from a roll (not s~own) of the ma~. ~
3 ~
As is common practice in the manufacture of conven-tional paper-faced gypsum board, the two opposite edge portions of the fîbrous mat 6 are progressively flexed upwardly from the mean plane of the mat 6 and then turned inwardly at the margins as to provide coverings for the edqes of the resulting board 40. In Figure 1, this progressive flexing and shapim~ of the edges o~ the mat 6 are shown for only one side edge of the mat and the conventional guiding devices which are ordinarily employed for this purpose are omitted from the ~igure for the sake of clarity. Figure 7 shows an edge of the set gypsum core 42 covered by the overlapped edge portion 6A of the mat 6. Figure 7 shows also score marks 10 and lOA of the mat 6, the score marks permitting the formation of good edges and flat surfaces. The score marks 10 and lOA are mad~ by a conventional scoring wheel 12. An advantage of using the preferred form of glass fiber mat is that it is capable of being scored and edged like conventional paper facing.
Another sheet o~ fibrous mat 16 is fed from a roll (not shown) onto the top of the slurry 4, ther~by sandwiching the slurry between the two moving fibrous mats which form the facing~ of the set gypsum core 42 which is formed ~rom the slurry. The mat~ 6 and 16 with the slurry 4 sandwiched there-between enter the nip between the upper and lower forming or shaping rolls 18 and 20, and are thereafter received on a conveyer belt 22. Conventional edge guiding devices, such as indicated at 24 shape and maintain the edges of the composite until the gypsum has set sufficientl~ to reta~n i~ s~ape. In 3.0 du~c~ursa,- seguential lengths o~ the b4ar~ ar.e c~t ~nd ~urthe~ prQcessed by exposure to heat which accelerate the drying o~. th~ board by increasing the rate of evaporation o~
excess water in the gyps~.slurry.
. . . . . ..
. . Wlth reference to Fi~e 7.,.it has been observed .
that ths set ~ypsum o~,*he cor~ ~2 is.~ective in formin~
309~31 satisfactory bonds with the mats and between the edge portions of the overlying mat 16 and the overlapped edge portion 6A.o~
the underlying mat 6, thus making it unnecessary to use a bond improver in th~ slurry or an edge paste to form th~
aforementioned bonds.
The preferred form of mats 6 and 16, as shown in Figures 2 and 3, comprises glass fiber filaments 30 oriented in random pattern and bound together with a resin bind~r (not shown).
A preferred form of glass fiber mat-faced yypsum board 40 is shown in Figures 4 and 7. ~t comprises one in which the set gypsum of the core 42 penetra~e~ substantially through the thickness of the mat 6 over substantial aFea portions thereof and in which the set gypsum or the core ~2 penetrates the mat 16 partially, with the suEfa~e being thus substantially free of set gypsum. ~he gypsum-free surface of mat 16, as seen in Fiqure 8, is highly textured, and provides an excellent substrate for adhering thereto an overlying component inasmuch as it comprises many interstices into which an adhesive composition can flow and bond.
In shipping ~ypsum board, it is convenient to package two boards 40 and 40A together (see Figure 10 and 11), with the glass ~iber gypsum-free surfaces 41 and 41A in face to face relationship, and thus protected, and with the gypsum-coated surfaces (for example, 43A in Fiqure 11) forming ~.he outside of the package. The set gyp~um on ~he outside surfaces helps to keep the board from being damaged during handling, shipping and storage, and protects the skin of those who come in contact with`~ è board ~rom being irritated by the glass fibers of the mat.
The phrase ~substantially penetrated hy set gypsumn, as used herein, means that-the set gypsum of the core~ extends fro~`th~ ma~ sur~ace which is con~i~uous to the core to the . - . . . :
23 60382-1~68E
outer mat surface and coats glass flbers on the outer surface with a thin film of set gypsum to the e~tent that the outline of glass flber~ can be ~een through the thin fllm of set gypsum. The phrase "over substantlal area portions of the outer surface", as used hereln, means that about 30 to about 75% of the outer surface area of the mat is substantially penetrated by set gypsum.
Preferably, about 45 to about 55% of the outer surface area of the mat is substantlally panetrated by set gypsum. Accordlngly, the gypsum-coated surface of thls preferred embodiment of the board comprlses a surface that has a roughened or patterned appearance~
it does not comprlse a smooth continuous coating oE ~et ~ypsum.
Thls preferred form of board can be ~ormed with relatively small amounts of gypsum slurry being deposlted on the underlylng support surface, thus mlnimizing the need to clean the surface.
The need for such cleanlng can be substantlally avolded by ad~usting the viscosity of the slurry so that it penetrates but part-way through the underlying fibrous mat, for example, up to about 50% of lts thlckness. Thus, this preferred form of board has to gypsum-free fiber-faced surfaces.
The manufacture of the aforementioned preferred forms o~
board can be accomplished by controlllng the v1scosity of the aqueous slurry of the calcined gypsum in a manner such that the slurry penetrates the underlying and overlylng mats to the de~lred degree. In manufacturlng each of the a~orementioned preferred forms of board the viscosity of the slurry should be such that it penetrates about lO to 50% of the thlckness of the overlying mat over the entire surface thereof.
The recommended means ~or controlling the vlscosity of ~3~g~31 24 6~382--126 the slurry ls to a~d thereto a vi~coslty-control agent. Such vlscoslty-control agents are known in the field of gypsum board manufacture. A preferred vlscoslty-control agent is paper flber.
~xamples of other agents that can be used are celluloslc thickeners, bentonite clays and starches.
The particular viscosity values that are used in ~he manufacturlng operation can vary from one appllcation to the next, dependlng on the poroslty of the mat, and the desired penetratlon of the slurry. Accordingly, for any partlcular appllcatlon, the vlscoslty value ls best determined empirlcally.
In using the preferred form o~ glass fiher mat, as descri~ed above, to manufacture the aforementioned preferred ~orms of board, developmental work has shown that satisfactory results can be achleved utllizing a gypsum slurry having a viscosity wlthln the range of about 5000 to 70Q0 cp. As used hereln, the vlscoslty value refers to Brookfleld viscoslty measured ak a temperature of 70F at 10 rpm utlllzing paddle No. 3. It should be appreclated that the amount of vlscoslty-control agent added to the slurry to glve the desired vlscoslty wlll vary dependlng on the partlcular agent used and the speclfic vlsco~lty deslred.
In preferred form, the core of the ~lbrous mat-faced gypsum board has a denslty of about 40 to about 50 lbs/cublc ft., most preferably about 42 to about 45 lbs/cublc ft. The manu-facture of cores havlng densltles wlthln the preferred range can be ef~ected by using known techniques, for example, by introducing an approprlate amount o~ ~oam into ~he aqueous gypsum slurry ~rom which the core i8 formed. There ar~ welght advantages tha~ can be reallzed by the use of flbrous matfaced gypsum board ln EISystems , ~, ~3~ 3~
24a 60382-1268E
ln that fibrous mats which are lighter in weight than conventional paper facing are available. Eor example, the welght of a widely used paper facing in the manufacture of conventional gypsum sheathlng ls ln the range of about 120 lbs~1000 sq. ~t. of board, whereas the weight of a preferred form of glass flber mat for use ln the . _ ~3~83 ~
present invention is about 40 lbs/1000 sq. ~t. of board.
Turning now to Figures 12 and 13, there is shown therein an example of an exterior insulating sys~em fabrica~ed in accordance with the present invention and comprising the exterior portion of the building 81. The EISystem 80 comprises panels of ~ibrous mat-faced board 82 affixed by nails 84 to wood framing 86. A foamed polystyrene panel 88, about 1 inch thick, i5 adhered to the fibrous mat-faced board 82 by adhesive 90. A rein~orcing member comprising glass fiber scrim 92 is sandwiched between the polystyrene panel 88 and the ~inal finishing material 94 by adhesive 96.
Various o~ the preferred forms o the gypsum board of the present invent~on can be used also to good advantage in place of conventional qyp~um sheathing in applications other than EISystems. Thus, the preferred forms of board can be used as an underlying suppor~ surfac~ which is coversd with overlying finishing materials, for example, aluminum, wood siding, plaster and Portland cement stucco.
EX~MPLES
The ~ormulation set forth below is an example o~ a : 25 preferred a~ueous gypsu~ slurry which can be used in making the core of a gypsum support member in accordance with the : present invention.
Consti~ent~ Lb8. ~1000 sq.~t. of b~oard calcined gypsum 1380 ( aS0-1/2 H20) wax/asphalk emulsion 130 aqueous solution o~ lO w~.%
polytvinyl alcohol) 56 paper ~iber 15 35 set accelerator 6 ammonium lauryl sulfonate (foaming agent) calcium li~nosulfonate (dispersing agent) 2 water 260 ;
~9~31 The wax/asphalt emulsion used in the above formulation contained approximately 48 wt.% ~olids of which about 11 wt.%
was paraffin wax and-about 37 wt.% was asphalt. The set accelerator comprised about 80 wt.% potash, about 12 wt.%
lignosulfonate and about 8 wt.% ground yypsum.
The above formulation was used to prepare gypsum board, the surfaces of which were covered with nonwoven fiber glass mat. The mat was composed of glass fiber filaments oriented in a random pattern bonded together by an adhesive referred to by the manufacturer as a ~modified urea-formaldehyde resin~. The mat had a thickness of 33 mils, was more porous than paper of the type used as the cover sheet of .. . .... . .
gypsum wallbQard,,and was not significantly weakened by water, The air permeability of the mat was 700 CFM/sq. ~t. (test method FG 436-91~. The mat is available commercially as DURA-GLASS 7502-~ lbs. and is an example of a preferred fibrous mat for Use in the practice of the present invention.
Continuous length board was made from the above gypsum slurry and gla s fiber mat on a conventional wallboard machine. The slurry wa~ ~ed onto a moving sheet of the mat as it was unrolled from a roll onto a moving support sur~ace.
The mat had a width of about 51 inches and was scored continuously by con~entional scoring blades prior to the depo~ition o~ the ~lurry thereon. Each edge of the mat was scored with ~wo score marks, with each of the outer score~
b~ing about 1 inch from its respective edge of the mat-and:
each o~ the inner scores being about 1 1/2 inch ~rom its re~pective edge. After the slurry Was deposited-on the mat, the edges were folded at the score marks and overlapped on top of the slurry. (The gypsum core formed ~rom this opëration ' had a width of 47 7/8 inches and a thicknes~ of 1j2 inch.) Mat from another roll thereof and having a width of 47 1/2 inches was fed onto the top of the gypsum slurry and the overlapped edge portion~ of the underlying mat. The gypsum 3~831 slurry penetrated the overlapped edge portions and served to bo~d t~e edge portions of the overlying mat to the overlapped edge portions o~ the underlying mat.
The viscosity of the gypsum slurry was about 5900 cp at 70F. At this viscosity, the slurry penetrated substantially throu~h some portions of the underlying mat to form a thin film thereof on about 40 to 50% of the area o~ the outer surface of the mat. As the gypsum in ~he film set, substantial portions of the outer surface of the mat were covered with a thin film of set gypsum. The surface had a roughened appearance with outlines of the glass filaments bei~g observable underneath the thin coatings of gypsum which covered them. However, at the aforementioned viscosity, the s}urry penetrated but a portion (about 5 mils) of the thicknesq o~ tha overlying mat oYer the entire area thereof, with no ~lurry being observed on the outer surface of the mat.
A~ the gypsum 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 gypsum cors.
The continuous length board is cut into lengths of about 8 feet. Drying o~ the gypsum board is accelerated by heating in an oven at 350F for about 2 hours and until the board is almo~t dry and then at 200F for about 1 hour until it i~ dried completely. The density o~ the board is about 43 lb.
cu.ft.
Th~ gypsum-free surfaces o~ panels (2' X 2') oP
glass fibër-f~ced board as described above were adhered to panels o~`expande~ po~'ys~ren~'utill'z`ihg ~wo different commercially a~a~là~lé adhesive sy~tem~. In one system, hereafter ~Sys~ëm A~, on~ of the ~aces o~ a paneI ~f expanded polystyrenë having a thicknë~s of ~o~t I i~ch a~ 2' X ~' was smeared with an adhesive mix~ure comprising cement~, sand, and resin binder u~ilizing a 3/8n X 3~8~ toothed trowel. The panel was then adhered to ~he glas~ fiber-~aced gyp~um board.
. . .~
~3~31 Thereafter, glass fiber reinforcing mesh was applied to the other fa~e of the panel of expanded polystyrene and a decorative finish was applied ~o the mesh.
In the other system, hereafter ~System B", the same steps a described above for System A were followed except that an acrylic adhesive was applied to the gypsu~-free surface of the board and the polystyrene panel adhered thereto.
Two additional systems like Systems A and B above were assembled, except that conventional paper-faced gypsum sheathing wa~ substituted for the glass fiber-~aced gypsum board in each of ~ystems A and ~.
The integrity o~ each of the systems was evaluated using 1 1/2" X 1 1/2~ cross-sectional cubes which were extracted from the systems and which were pulled apart in a tensile test apparatus. The results o~ the testing are set ~orth below.
Fiber Glass- Paper-~y~ Faced Board Faced Board A 100~ break in 66% break in the the polystyrene paper, 33% break panel in the polystyrene B 100% break in 100% break in the the polystyrene paper panel From t~ above re~ults, it can be ~een that the use of tha glas~ fiber-faced gypsum support surface improved signifi-ca~ly the strength o~ the assembly in that tensile failure wa.~;trans.ferred ~rom the paper cover of ~he gypsu~ ~heathing to ~h~ ~oamed polystyrene, with no failure at all experienced in the glass ~iber mat or the gypsum core to which it wa~
adhered. Thu$~ hould b~ ap~reciated t~t, in accordance wit~ the~present:inYention~ th~ in~ri~y sf an EI~stem ca~
, ... .. ..
13~831 be improved significantly becaus~ it is no longer dependent upon the ply strength of a paper co~er sheet, but upon a component having much higher strength. ~ ~
Glass fiber-faced gypsum boards, made as described above, and with their edges protected, were placed outdoors for several months and exposed to the elements. During that period, the boards were exposed to a~out 20 inches of rain.
After this exposure, the boards were examined and ~ound to be lo in excellent condition with no signs of deterioration~
Other outdoor tests have shown that glass fiber mat-faced gypsum board in accardance with the presen~ invention and having a core which includes wax-asphalt emulsion as a water-resistant a~ditive better resists deterioration than a like board having a core which in~ludes``sodium methyl siliconata as the water-resistant additiY~.;
\ Gy~sum board comprising a set gypsum core faced with 20¦ a fibrous mat, as described herein, and pr~erably gypsum i board comprising a set gypsum core sandwiched between two sheets of porous glass mat, can be used to particular advanta~e also a~ a component of a shaft wall assembly or similar asse~bly in the interior of a building. In such application, the fibrous mat-~aced board can be us~d to particular ad~antage in place o~ conventional paper-faced gypsum core board or shaft liner pane}s~ the core o~ which generally include~ fire-resistant additive~. Assemblies of this type g~nerally comprise metal framework or studs for support o~ th~ gypsum panels which ~orm ~ha wa~ls of the shafts of elevators~ stairwells and the lika. Example o~
such assemblies are shown in U.S. Patent Nos. 4,047,355;
4,324,0B2 and 4~364,212. Fibrous mat-~aced board~ as described hsrein, can be used, for example, in the a~semblies described in th~ aforementioned patents, and particularly as the shaft liner panel. For use in such application, th core of th~ board can include fixe resistant additives.
30 ~L3~983~
In summary, it can be said that the present invention provides in a practical way important functional improvements in exterior finishing systems for buildings, including particularly exterior insulating systems, and in shaft wall assemblies.
;, , ' .
Claims
THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Gypsum board comprising a set gypsum core faced with a fibrous 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, wherein said core absorbs less than 5% water when tested in accordance with ASTM
method C-473.
2. Gypsum board in accordance with claim 1, wherein said core is sandwiched between two sheets of porous glass fiber mat, is prepared from a calcined composition containing at least about 3 wt% wax-asphalt emulsion.
3. Gypsum board in accordance with claim 1, wherein said core contains at least about 3 wt% of a water-resistant additive.
4. Gypsum board according to claim 3, wherein said core is prepared from a calcined gypsum composition including also poly (vinyl alcohol).
5. An exterior insulation system including as a support surface the gypsum board of claim 2, wherein insulating material is adhered to said mat having an outer surface which is substan-tially free of set gypsum.
6. An exterior insulation system including as a support surface the gypsum board of claim 1, and wherein insulating material is adhered to said mat having an outer surface which is substantially free of set gypsum.
7. Gypsum board in accordance with claim 1, wherein said mat is a glass fiber mat comprising randomly distributed glass filaments bonded by an adhesive material.
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Gypsum board comprising a set gypsum core faced with a fibrous 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, wherein said core absorbs less than 5% water when tested in accordance with ASTM
method C-473.
2. Gypsum board in accordance with claim 1, wherein said core is sandwiched between two sheets of porous glass fiber mat, is prepared from a calcined composition containing at least about 3 wt% wax-asphalt emulsion.
3. Gypsum board in accordance with claim 1, wherein said core contains at least about 3 wt% of a water-resistant additive.
4. Gypsum board according to claim 3, wherein said core is prepared from a calcined gypsum composition including also poly (vinyl alcohol).
5. An exterior insulation system including as a support surface the gypsum board of claim 2, wherein insulating material is adhered to said mat having an outer surface which is substan-tially free of set gypsum.
6. An exterior insulation system including as a support surface the gypsum board of claim 1, and wherein insulating material is adhered to said mat having an outer surface which is substantially free of set gypsum.
7. Gypsum board in accordance with claim 1, wherein said mat is a glass fiber mat comprising randomly distributed glass filaments bonded by an adhesive material.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US06/583,874 US4647496A (en) | 1984-02-27 | 1984-02-27 | Use of fibrous mat-faced gypsum board in exterior finishing systems for buildings |
| US583,874 | 1984-02-27 | ||
| CA000473643A CA1250727A (en) | 1984-02-27 | 1985-02-06 | Use of fibrous mat-faced gypsum board in exterior finishing sytems for buildings and shaft wall assemblies |
| CA000589064A CA1293606C (en) | 1984-02-27 | 1989-01-24 | Fibrous mat-faced gypsum board |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000589064A Division CA1293606C (en) | 1984-02-27 | 1989-01-24 | Fibrous mat-faced gypsum board |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1309831C true CA1309831C (en) | 1992-11-10 |
Family
ID=27167495
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000616157A Expired - Lifetime CA1309831C (en) | 1984-02-27 | 1991-09-09 | Fibrous mat-faced gypsum board |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1309831C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108824800A (en) * | 2018-08-08 | 2018-11-16 | 郑州三迪建筑科技有限公司 | A kind of building template free of demolition |
-
1991
- 1991-09-09 CA CA000616157A patent/CA1309831C/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108824800A (en) * | 2018-08-08 | 2018-11-16 | 郑州三迪建筑科技有限公司 | A kind of building template free of demolition |
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