CA1189434A - Wallboard made from gypsum and plastic facing material - Google Patents
Wallboard made from gypsum and plastic facing materialInfo
- Publication number
- CA1189434A CA1189434A CA000396368A CA396368A CA1189434A CA 1189434 A CA1189434 A CA 1189434A CA 000396368 A CA000396368 A CA 000396368A CA 396368 A CA396368 A CA 396368A CA 1189434 A CA1189434 A CA 1189434A
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- CA
- Canada
- Prior art keywords
- gypsum
- product
- board
- polymeric
- film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Abstract
ABSTRACT
This invention relates to a new improved gypsum wallboard product and to a novel method of making the improved gypsum wallboard product. The gypsum wallboard product comprises a gypsum core substantially enclosed within a water vapour permeable synthetic polymeric sheeting. The invention also relates to a process for the preparation of a gypsum wallboard product comprising spreading a fluid gypsum hemihydrate slurry between two substantially parallel vapour permeable polymeric sheets and allowing the gypsum hemihydrate to set and bond to the sheets.
This invention relates to a new improved gypsum wallboard product and to a novel method of making the improved gypsum wallboard product. The gypsum wallboard product comprises a gypsum core substantially enclosed within a water vapour permeable synthetic polymeric sheeting. The invention also relates to a process for the preparation of a gypsum wallboard product comprising spreading a fluid gypsum hemihydrate slurry between two substantially parallel vapour permeable polymeric sheets and allowing the gypsum hemihydrate to set and bond to the sheets.
Description
3~
FIELD OF THE INVENTION
This invention relates to a new improved gypsum wallboard product and to a novel method of making the improved gypsum wallboard product. More particu-S larly, t~lis invention is directed to a gypsum wallboardproduct that is produced using water vapour permeable synthetic polymeric facing materials enclosing a gypsum core.
BACKGROUND OF THE INVENTION
Gypsum wallboard is traditionally manufactured by a continuous process wherein a slurry of calcium sulphate hemihydrate, water, water reducing agents, bonding agents, set control agents and anti-burning agents is deposited on a lower, continuously advancing web of paper, and an upper, continuously advancing web of paper is laid over the slurry. The paper and gypsum slurry are passed between parallel horizontal upper and lower forming rolls and integrated into a continuous Elat envelope of paper enclosing the unset gypsum. The ~0 continuous product thus formed is conveyed on a continuous moving belt until the slurry has set. The strip or sheet is then cut to form boards of prescribed length, after which they are passed through an oven or kiln to be dried until the excess water in the gypsum board has evaporated.
In the production of gypsum wallboard it is customary to use multi-ply paper facing materials which are generally manufac-tured from waste paper grades or other pulp sources, employing conventional papermaking techniquesD Wallboard paper liners produced by 3~
conventional papermaking processes possess a number of inherent properties or characteristics which detriment-ally affect the final gypsum wallboard product. One such property is the difference in tensile strength between the machine direction of the paper (the direction of the paper as it travels through the paper makiny machinery) and the cross (lateral) direction (right angle to the machine direction3. Typically the machine direction tensile strength is three to four times stronger than the cross (lateral) directional strength. This imbalance of paper strength properties results in a finished gypsum board product with dis-similar direc-tional strength characteristics. Since a minimum specification degree of strength must be achieved by the gypsum board, regardless of paper direction, the board and paper strength requirements are necessarily determined by their weakest direction. As a result of this anisotropy of the paper, and in compen-sation of the imbalance, a relatively thick paper liner (thicker than necessary in the in machine-line direc-tion) must be used if minimum strength requirements are to be met.
A further disadvantage of wallboard paper liners is their susceptibility to abrasion surface damage on the face of the wallboard due to the rela-tively soft fibrous nature oE the cellulosic ingredients of the paper and to the relatively weak chemical forces which hold the fibres togetherO A coating of some type is always required to increase the resistance of this product to darnage after application. In spite of this ~B~
protective coating, the gypsum wallboard face still has relatively poor resistance to abrasion and impact force.
This deficiency is most detrimental to the product Eor applications in high occupancy buildings SUCil as banks, offices, and the like. To overcome this problem, gypsum wallboard is commonly covered with a decorative poly-vinylchloride plastic film applied to the gypsum wallboard sur-face.
Production of an abrasion and impact resistant wallboard by substituting a plastic film for the wall board paper liner in the primary manufacturing process is generally not possible since the plastic film is impermeable to water vapour thereby making it impossible to dry the wallboard. Normally, an abrasion resistant, impact resistant, vinyl covered wallboard tknown generically as vinyl board) is produced by a secondary manufacturing operation in which the decorative vinyl film is adhesively laminated to the face surface of the gypsum wallboard. This ancillary operation substan-tially increases the cost of the finished wallboardproduct.
The degree with which paper products undergo changes in physical properties upon adsorption or absorption of water can also affect the manufacture and use of conventional gypsum board. The manufacturing process is affected by the adsorbed water content of the paper being used. This in turn is dependent on several factors such as time since manufacture, storage conditions, and the like. The rate of water absorption into the paper from the gypsum slurry is also a function 3~
of many parameters and is of great importance in the production of a quality gypsum board product. Paper expansion due to the efEect of the water absorption by the paper must be taken into account if a gypsum board of correct dimensions is to be obtained. Considerable effort has been made to overcome these problems using sizing agents during paper manufacture.
The effect of water adsorption and subsequent paper expansion also limits the types of applications considered acceptable for some gypsum board produc-ts.
Under conditons of high humidity, for example, the use of a low caliper (9.5 mm~ gypsum board for ceiling applications can result in the gypsum board sagging between the support structures. One major factor contributing to this effect is the expansion of the paper liner such that it no longer supports the core.
This problem can be especially serious if the gypsum board produc-t is held at ceiling level using support tracking, etc. rather than by direct attachment using nails or screws.
SUMMARY OF THE INV~NTION
We have discovered that certain types of water vapour permeable plastic (synthetic polymeric) film or sheeting can be used instead of wallboard paper liners to produce a decorative gypsum wallboard with excellent abrasion, impact and sag resistance properties.
Surprisingly, the plastic films can be used in the primary gypsum wallboard manufacturing process and the wallboard can be satisfactorily dried without detriment to the bond between the plastic facing material and the gypsum wallboard core. Furthermore, achieving the produc-tion oE a gypsum wallboard with a decorative plastic finish without processing through a secondary laminating operation has been entirely unexpectecl to those skilled in the art o wallboard manu~acture.
The plastic films comprise a family of spun-bonded polymers such as poly-olefins which family is produced by first spinning continuous strands of the polymers, such as high-densi~y polyethylene into a very fine, interconnected web of fibres and then bonding the fibres together with heat and pressure. The product after bonding displays a good printing or coating surface, high opacity, and touyhness to a degree unique among sheet or film produc-ts of similar weiyht.
lS The invention is directed to a gypsum wall-board product which comprises a gypsum core, at least one side oE which is substan-tially covered by a water vapour permeable synthetic polymeric web which may be composed of spunbonded polymeric filament or spunbonded polyolefin filament.
In the product according to the invention, the polyolefin may be polyethylene and particularly high-density polyethylene. The spunbonded polyolefin filament shee-ting or film may be a product available from DuPont of Canada Limi-ted in association with the trade mark TYVEK.
The invention is also directed to a process for the preparation of a gypsum wallboar~ product comprising sprecding a fluid gypsum hemihydrate slurry between two subs-tantially paralle] vapour permeable 3~
sheets, at least one of which is synthetic polymer, and allowing the gypsum hemihydrate to set and bond to the sheets. In the process, the product may be passed through an oven to remove excess water in the gypsum board. The polymeric sheeting or film may be composed of spunbonded polyolefin filament, for example, high densi-ty polyethylene Eilament.
DETAILED DESCRIPTION OF THE INVE~TION
Gypsum wallboard samples were prepared in the laboratory using spunbonded olefin liners. The board products were evaluated in a number of standard testng procedures using a regular, paper lined gypsum board as a control sample.
The following examples demon~trate the properties of this new product and the process by which it is made.
Example 1 A laboratory board sample 1/2 inch (12.7 mm) thick was prepared using the spun bonded polyethylene sheeting in the following manner. A piece of Tyvek*
1085 sheeting (spunbonded high density polyethylene) was cut with dimensions 14-1/2" (368.3 mm) by 28" (711.2 mrn). The specific product used was uncoated Tyve~*, but other sheetirlg manufactured in the same manner with t~e same range of propertie~ would be suitable. This material was folded and creased at positions 3/4" (19.05 mm) and 1-1/4" (31.75 mm) from each of -the 28" edges to form an envelope similar to that used in the conven--tional gypsum board process. This envelope was then clamped in a laboratory board forming apparatus. A
piece of liner of dimensions 11-3/~" (298.5 mm) by 28"
(711.2 mm) was also clamped in the laboratory board forming apparatus such that it would Eorm the back Eace of the Laboratory board. Double sided adhesive tape was applied to the bottom sheeting alonc3 a 3/~" (19.05 mm) wide strip to come into contact with the upper liner sheet upon sample preparation.
The slurry to be used in preparation of the board sample was prepared as follows. a surfactant foam solution (173 ml at 0.7% by weight Cedepal* FA406 foaming agent) was premixed for one minute using two Hamilton Beach Scovill Mixers (Model 936-2SA) at high speed (86.5 ml in each mixer cup). While mixing the foam, a mixture of calcium sulphate hemihydrate (1563 g) and ground gypsum accelerator (1.13 g) was added to the bowl of a Hobart* Model N-50 mixer containing 1042 ml of water, 3.63 g o~ paper pulp, 1.62 g of Lornar D*
superplasticizer and 11.34 g of starch. The mixture was stirred at low speed for 2 seconds and the premixed foam was added to the bowl. The entire mixture was stirred at high speed for 30 seconds. The resultant slurry was poured onto the bottom sheet of the laboratory board apparatus and the top sheet rolled into place using a heavy steel roller.
Upon setting, the apparatus was dismantled and the sample was trimmed to a length of 16" (406.4 mm).
This sample was then dried in a circulating air oven at 115C or 60 minutes, and then at 40C overnightO
Performance Tests .
The laboratory board sample prepared according * Trade Marks 3~
to the procedure in Example 1 above was compared to a sample of commercial 12.7 mm board by performing the following tests:
Comparison of Spun-bonded Polyethylene Covered Gypsum Board to Commercial Gypsum Board Commercial Tyvek* Test Gypsum 1085 Method Prope~y Board _ Board Reference Thickness (mm)12.7 12.7 Weight(kg/lOOm2)899 934 Breaking Strength (N) Cross225 250 Machine 776 250 Nailhead Pull Resistance (N) 487 507 Humidified Deflection (mm) 25 5 Impact Resistance (joules/mm)0.356 0.783 2 Bond (N/76 mm) Peak 35 24.5 3 Plateau 13 22.0 3 Durability (mm/100 revolutions)0.254 OoOOl 4 Test Methods Reference 1 Canadian Standards Association A82.20.3-M
1977.
Reference 2 Canadian Government Specifications Board 41-GP-24.
Reference 3 Measurements of bond of the liner to the core were performed by cut-ting a 3 inch (76.2 mm) wide * Trade Marks 3~
portion of board 12 inches (304O8 rnm) long, scoring one side, breaking the core and using an Instron testing apparatus to measure the force required to pull the liner away ~rom the core at 90C. The peak value corresponds -to the maximum Eorce required, whereas the plateau value corresponds to the flat section of the bond strength curve immediately after the peak.
R rence 4 Durability was measured using a Tabor* Abraser equipped with CS-10 abrasion wheels. The measurements were performed using the 250 g arms as load to the abrasion wheels. After 1000 revolutions, the samples were measured using a micrometer at four locations inside the abrasion ring and four locations immediately adjacent to the abrasion ring. The difference between the average of these two sets of data was reported.
Example 2 To demonstrate the improved characteristics of a gypsum board product of reduced thickness, samples were prepared using Tyvek* 1073 sheeting in which the overall thickness was 6.35 mm. The procedure used was the same as outlined in Example 1 except the spacers in the moulding table were 6.35 mm thick, the bottom liner was 35.6 cm wide and creased 19.1 mm and 25.4 mm from each 71.1 cm edge, and the foam solution was added directly to the water rather than premixing using the Hamilton Beach mixer.
The board samples produced were then tested and compared to commercial 12.7 mrn board as shown by the following TableO As can be seen from these results, the * Trade Marks ~8~
spunbonded oleEin sheeting product ofEered several advantages over the conventional 12.7 mm board. The data indicates that the product would be suitable for ceiling tile applications.
5Comparison oE Spun-bonded Polyethylene Covered G~psum Board to Commercial Gypsum Board Commercial Tyvek* Test Gypsum 1073 Method Propert~ Board Board Reference (Sample No.) (A) (B) (1) (2) Thickness (mm)12.7 12.7 6.35 6.35 Weight(kg/lOOm2~899 879 626 804 Brealcing 5trength (N) Cross225 Machine776 103 Nailhead Pull Resistance (N)487 231 Humidified Deflection (mm) 18 5 SurEace Water Resistance (g)2.1 1.1 Impact Resistance (joules/mm)0.356 0.712 2 Test Methods 1 and 2 as described in Example 1.
As will be apparent to those skilled in the art in the light of the fore~oing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
* Trade Marks
FIELD OF THE INVENTION
This invention relates to a new improved gypsum wallboard product and to a novel method of making the improved gypsum wallboard product. More particu-S larly, t~lis invention is directed to a gypsum wallboardproduct that is produced using water vapour permeable synthetic polymeric facing materials enclosing a gypsum core.
BACKGROUND OF THE INVENTION
Gypsum wallboard is traditionally manufactured by a continuous process wherein a slurry of calcium sulphate hemihydrate, water, water reducing agents, bonding agents, set control agents and anti-burning agents is deposited on a lower, continuously advancing web of paper, and an upper, continuously advancing web of paper is laid over the slurry. The paper and gypsum slurry are passed between parallel horizontal upper and lower forming rolls and integrated into a continuous Elat envelope of paper enclosing the unset gypsum. The ~0 continuous product thus formed is conveyed on a continuous moving belt until the slurry has set. The strip or sheet is then cut to form boards of prescribed length, after which they are passed through an oven or kiln to be dried until the excess water in the gypsum board has evaporated.
In the production of gypsum wallboard it is customary to use multi-ply paper facing materials which are generally manufac-tured from waste paper grades or other pulp sources, employing conventional papermaking techniquesD Wallboard paper liners produced by 3~
conventional papermaking processes possess a number of inherent properties or characteristics which detriment-ally affect the final gypsum wallboard product. One such property is the difference in tensile strength between the machine direction of the paper (the direction of the paper as it travels through the paper makiny machinery) and the cross (lateral) direction (right angle to the machine direction3. Typically the machine direction tensile strength is three to four times stronger than the cross (lateral) directional strength. This imbalance of paper strength properties results in a finished gypsum board product with dis-similar direc-tional strength characteristics. Since a minimum specification degree of strength must be achieved by the gypsum board, regardless of paper direction, the board and paper strength requirements are necessarily determined by their weakest direction. As a result of this anisotropy of the paper, and in compen-sation of the imbalance, a relatively thick paper liner (thicker than necessary in the in machine-line direc-tion) must be used if minimum strength requirements are to be met.
A further disadvantage of wallboard paper liners is their susceptibility to abrasion surface damage on the face of the wallboard due to the rela-tively soft fibrous nature oE the cellulosic ingredients of the paper and to the relatively weak chemical forces which hold the fibres togetherO A coating of some type is always required to increase the resistance of this product to darnage after application. In spite of this ~B~
protective coating, the gypsum wallboard face still has relatively poor resistance to abrasion and impact force.
This deficiency is most detrimental to the product Eor applications in high occupancy buildings SUCil as banks, offices, and the like. To overcome this problem, gypsum wallboard is commonly covered with a decorative poly-vinylchloride plastic film applied to the gypsum wallboard sur-face.
Production of an abrasion and impact resistant wallboard by substituting a plastic film for the wall board paper liner in the primary manufacturing process is generally not possible since the plastic film is impermeable to water vapour thereby making it impossible to dry the wallboard. Normally, an abrasion resistant, impact resistant, vinyl covered wallboard tknown generically as vinyl board) is produced by a secondary manufacturing operation in which the decorative vinyl film is adhesively laminated to the face surface of the gypsum wallboard. This ancillary operation substan-tially increases the cost of the finished wallboardproduct.
The degree with which paper products undergo changes in physical properties upon adsorption or absorption of water can also affect the manufacture and use of conventional gypsum board. The manufacturing process is affected by the adsorbed water content of the paper being used. This in turn is dependent on several factors such as time since manufacture, storage conditions, and the like. The rate of water absorption into the paper from the gypsum slurry is also a function 3~
of many parameters and is of great importance in the production of a quality gypsum board product. Paper expansion due to the efEect of the water absorption by the paper must be taken into account if a gypsum board of correct dimensions is to be obtained. Considerable effort has been made to overcome these problems using sizing agents during paper manufacture.
The effect of water adsorption and subsequent paper expansion also limits the types of applications considered acceptable for some gypsum board produc-ts.
Under conditons of high humidity, for example, the use of a low caliper (9.5 mm~ gypsum board for ceiling applications can result in the gypsum board sagging between the support structures. One major factor contributing to this effect is the expansion of the paper liner such that it no longer supports the core.
This problem can be especially serious if the gypsum board produc-t is held at ceiling level using support tracking, etc. rather than by direct attachment using nails or screws.
SUMMARY OF THE INV~NTION
We have discovered that certain types of water vapour permeable plastic (synthetic polymeric) film or sheeting can be used instead of wallboard paper liners to produce a decorative gypsum wallboard with excellent abrasion, impact and sag resistance properties.
Surprisingly, the plastic films can be used in the primary gypsum wallboard manufacturing process and the wallboard can be satisfactorily dried without detriment to the bond between the plastic facing material and the gypsum wallboard core. Furthermore, achieving the produc-tion oE a gypsum wallboard with a decorative plastic finish without processing through a secondary laminating operation has been entirely unexpectecl to those skilled in the art o wallboard manu~acture.
The plastic films comprise a family of spun-bonded polymers such as poly-olefins which family is produced by first spinning continuous strands of the polymers, such as high-densi~y polyethylene into a very fine, interconnected web of fibres and then bonding the fibres together with heat and pressure. The product after bonding displays a good printing or coating surface, high opacity, and touyhness to a degree unique among sheet or film produc-ts of similar weiyht.
lS The invention is directed to a gypsum wall-board product which comprises a gypsum core, at least one side oE which is substan-tially covered by a water vapour permeable synthetic polymeric web which may be composed of spunbonded polymeric filament or spunbonded polyolefin filament.
In the product according to the invention, the polyolefin may be polyethylene and particularly high-density polyethylene. The spunbonded polyolefin filament shee-ting or film may be a product available from DuPont of Canada Limi-ted in association with the trade mark TYVEK.
The invention is also directed to a process for the preparation of a gypsum wallboar~ product comprising sprecding a fluid gypsum hemihydrate slurry between two subs-tantially paralle] vapour permeable 3~
sheets, at least one of which is synthetic polymer, and allowing the gypsum hemihydrate to set and bond to the sheets. In the process, the product may be passed through an oven to remove excess water in the gypsum board. The polymeric sheeting or film may be composed of spunbonded polyolefin filament, for example, high densi-ty polyethylene Eilament.
DETAILED DESCRIPTION OF THE INVE~TION
Gypsum wallboard samples were prepared in the laboratory using spunbonded olefin liners. The board products were evaluated in a number of standard testng procedures using a regular, paper lined gypsum board as a control sample.
The following examples demon~trate the properties of this new product and the process by which it is made.
Example 1 A laboratory board sample 1/2 inch (12.7 mm) thick was prepared using the spun bonded polyethylene sheeting in the following manner. A piece of Tyvek*
1085 sheeting (spunbonded high density polyethylene) was cut with dimensions 14-1/2" (368.3 mm) by 28" (711.2 mrn). The specific product used was uncoated Tyve~*, but other sheetirlg manufactured in the same manner with t~e same range of propertie~ would be suitable. This material was folded and creased at positions 3/4" (19.05 mm) and 1-1/4" (31.75 mm) from each of -the 28" edges to form an envelope similar to that used in the conven--tional gypsum board process. This envelope was then clamped in a laboratory board forming apparatus. A
piece of liner of dimensions 11-3/~" (298.5 mm) by 28"
(711.2 mm) was also clamped in the laboratory board forming apparatus such that it would Eorm the back Eace of the Laboratory board. Double sided adhesive tape was applied to the bottom sheeting alonc3 a 3/~" (19.05 mm) wide strip to come into contact with the upper liner sheet upon sample preparation.
The slurry to be used in preparation of the board sample was prepared as follows. a surfactant foam solution (173 ml at 0.7% by weight Cedepal* FA406 foaming agent) was premixed for one minute using two Hamilton Beach Scovill Mixers (Model 936-2SA) at high speed (86.5 ml in each mixer cup). While mixing the foam, a mixture of calcium sulphate hemihydrate (1563 g) and ground gypsum accelerator (1.13 g) was added to the bowl of a Hobart* Model N-50 mixer containing 1042 ml of water, 3.63 g o~ paper pulp, 1.62 g of Lornar D*
superplasticizer and 11.34 g of starch. The mixture was stirred at low speed for 2 seconds and the premixed foam was added to the bowl. The entire mixture was stirred at high speed for 30 seconds. The resultant slurry was poured onto the bottom sheet of the laboratory board apparatus and the top sheet rolled into place using a heavy steel roller.
Upon setting, the apparatus was dismantled and the sample was trimmed to a length of 16" (406.4 mm).
This sample was then dried in a circulating air oven at 115C or 60 minutes, and then at 40C overnightO
Performance Tests .
The laboratory board sample prepared according * Trade Marks 3~
to the procedure in Example 1 above was compared to a sample of commercial 12.7 mm board by performing the following tests:
Comparison of Spun-bonded Polyethylene Covered Gypsum Board to Commercial Gypsum Board Commercial Tyvek* Test Gypsum 1085 Method Prope~y Board _ Board Reference Thickness (mm)12.7 12.7 Weight(kg/lOOm2)899 934 Breaking Strength (N) Cross225 250 Machine 776 250 Nailhead Pull Resistance (N) 487 507 Humidified Deflection (mm) 25 5 Impact Resistance (joules/mm)0.356 0.783 2 Bond (N/76 mm) Peak 35 24.5 3 Plateau 13 22.0 3 Durability (mm/100 revolutions)0.254 OoOOl 4 Test Methods Reference 1 Canadian Standards Association A82.20.3-M
1977.
Reference 2 Canadian Government Specifications Board 41-GP-24.
Reference 3 Measurements of bond of the liner to the core were performed by cut-ting a 3 inch (76.2 mm) wide * Trade Marks 3~
portion of board 12 inches (304O8 rnm) long, scoring one side, breaking the core and using an Instron testing apparatus to measure the force required to pull the liner away ~rom the core at 90C. The peak value corresponds -to the maximum Eorce required, whereas the plateau value corresponds to the flat section of the bond strength curve immediately after the peak.
R rence 4 Durability was measured using a Tabor* Abraser equipped with CS-10 abrasion wheels. The measurements were performed using the 250 g arms as load to the abrasion wheels. After 1000 revolutions, the samples were measured using a micrometer at four locations inside the abrasion ring and four locations immediately adjacent to the abrasion ring. The difference between the average of these two sets of data was reported.
Example 2 To demonstrate the improved characteristics of a gypsum board product of reduced thickness, samples were prepared using Tyvek* 1073 sheeting in which the overall thickness was 6.35 mm. The procedure used was the same as outlined in Example 1 except the spacers in the moulding table were 6.35 mm thick, the bottom liner was 35.6 cm wide and creased 19.1 mm and 25.4 mm from each 71.1 cm edge, and the foam solution was added directly to the water rather than premixing using the Hamilton Beach mixer.
The board samples produced were then tested and compared to commercial 12.7 mrn board as shown by the following TableO As can be seen from these results, the * Trade Marks ~8~
spunbonded oleEin sheeting product ofEered several advantages over the conventional 12.7 mm board. The data indicates that the product would be suitable for ceiling tile applications.
5Comparison oE Spun-bonded Polyethylene Covered G~psum Board to Commercial Gypsum Board Commercial Tyvek* Test Gypsum 1073 Method Propert~ Board Board Reference (Sample No.) (A) (B) (1) (2) Thickness (mm)12.7 12.7 6.35 6.35 Weight(kg/lOOm2~899 879 626 804 Brealcing 5trength (N) Cross225 Machine776 103 Nailhead Pull Resistance (N)487 231 Humidified Deflection (mm) 18 5 SurEace Water Resistance (g)2.1 1.1 Impact Resistance (joules/mm)0.356 0.712 2 Test Methods 1 and 2 as described in Example 1.
As will be apparent to those skilled in the art in the light of the fore~oing disclosure, many alterations and modifications are possible in the practice of this invention without departing from the spirit or scope thereof. Accordingly, the scope of the invention is to be construed in accordance with the substance defined by the following claims.
* Trade Marks
Claims (11)
1. A gypsum wallboard product which comprises a gypsum core substantially covered by a water vapour permeable synthetic polymeric web.
2. A product as defined in Claim 1 wherein the polymeric web is spunbonded polymeric filament.
3. A product as defined in Claim 1 wherein the polymeric web is spunbonded polyolefin filament.
4. A product as defined in Claim 3 wherein the polyolefin is high-density polyethylene.
5. A product as defined in Claim 4 wherein the product is intended for use as ceiling tile.
6. A product as defined in Claim 3, 4 or 5 wherein the spunbonded polyolefin filament web is a spun bonded polyolefin sheeting or film.
7. A product as defined in Claim 1, 2 or 3 wherein only one face of the product is composed of synthetic polymeric sheeting or film.
8. A process for the preparation of a gypsum wallboard product comprising spreading a fluid gypsum hemihydrate slurry between two substantially parallel vapour permeable sheets or film at least one of which is a synthetic polymer, and allowing the gypsum hemihydrate to set and bond to the sheets.
9. A process as defined in Claim 8 wherein the product is passed through an oven to remove excess water in the gypsum board.
10. A process as defined in Claim 8 or 9 wherein the polymeric sheeting or film is of spunbonded polyolefin filament.
11. A process as defined in Claim 8 or 9 wherein the polymeric sheeting or film is of spunbonded high-density polyethylene.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000396368A CA1189434A (en) | 1982-02-16 | 1982-02-16 | Wallboard made from gypsum and plastic facing material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000396368A CA1189434A (en) | 1982-02-16 | 1982-02-16 | Wallboard made from gypsum and plastic facing material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1189434A true CA1189434A (en) | 1985-06-25 |
Family
ID=4122072
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000396368A Expired CA1189434A (en) | 1982-02-16 | 1982-02-16 | Wallboard made from gypsum and plastic facing material |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1189434A (en) |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5644880A (en) * | 1984-02-27 | 1997-07-08 | Georgia-Pacific Corporation | Gypsum board and systems containing same |
| US5704179A (en) * | 1984-02-27 | 1998-01-06 | Georgia-Pacific Corporation | Finishing and roof deck systems containing fibrous mat-faced gypsum boards |
| US6485821B1 (en) | 1999-02-25 | 2002-11-26 | E. I. Du Pont De Nemours And Company | Gypsum-based construction material |
| US6703331B1 (en) | 1999-02-25 | 2004-03-09 | E. I. Du Pont De Nemours And Company | Fungus resistant gypsum-based substrate |
| US6800361B2 (en) | 2002-06-14 | 2004-10-05 | E. I. Du Pont De Nemours And Company | Gypsum board having improved flexibility, toughness, abuse resistance, water resistance and fire resistance |
| WO2010114461A1 (en) * | 2009-04-01 | 2010-10-07 | Knauf Danogips Gmbh | A coating for a construction board, a construction board comprising the coating and a method for producing the construction board |
| US8282731B2 (en) | 2006-12-20 | 2012-10-09 | The Nugyp Corp. | Calcium sulfate hemihydrate treatment process |
| US9017495B2 (en) | 2000-01-05 | 2015-04-28 | Saint-Gobain Adfors Canada, Ltd. | Methods of making smooth reinforced cementitious boards |
| US10415245B2 (en) | 2004-02-23 | 2019-09-17 | Huber Engineered Woods, Llc | Panel for sheathing system and method |
| US11414865B2 (en) | 2012-05-31 | 2022-08-16 | Huber Engineered Woods Llc | Insulated sheathing panel |
| US11536028B2 (en) | 2004-02-23 | 2022-12-27 | Huber Engineered Woods Llc | Panel for sheathing system and method |
| US11801662B2 (en) | 2018-12-27 | 2023-10-31 | Gold Bond Building Products, Llc | Cementitious panels with polymeric-film facing material |
-
1982
- 1982-02-16 CA CA000396368A patent/CA1189434A/en not_active Expired
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US5704179A (en) * | 1984-02-27 | 1998-01-06 | Georgia-Pacific Corporation | Finishing and roof deck systems containing fibrous mat-faced gypsum boards |
| US5791109A (en) * | 1984-02-27 | 1998-08-11 | Georgia-Pacific Corporation | Gypsum board and finishing system containing same |
| US5644880A (en) * | 1984-02-27 | 1997-07-08 | Georgia-Pacific Corporation | Gypsum board and systems containing same |
| US6485821B1 (en) | 1999-02-25 | 2002-11-26 | E. I. Du Pont De Nemours And Company | Gypsum-based construction material |
| US6703331B1 (en) | 1999-02-25 | 2004-03-09 | E. I. Du Pont De Nemours And Company | Fungus resistant gypsum-based substrate |
| US9017495B2 (en) | 2000-01-05 | 2015-04-28 | Saint-Gobain Adfors Canada, Ltd. | Methods of making smooth reinforced cementitious boards |
| US6800361B2 (en) | 2002-06-14 | 2004-10-05 | E. I. Du Pont De Nemours And Company | Gypsum board having improved flexibility, toughness, abuse resistance, water resistance and fire resistance |
| US10415245B2 (en) | 2004-02-23 | 2019-09-17 | Huber Engineered Woods, Llc | Panel for sheathing system and method |
| US11536028B2 (en) | 2004-02-23 | 2022-12-27 | Huber Engineered Woods Llc | Panel for sheathing system and method |
| US11697939B2 (en) | 2004-02-23 | 2023-07-11 | Huber Engineered Woods Llc | Panel for sheathing system and method |
| US8282731B2 (en) | 2006-12-20 | 2012-10-09 | The Nugyp Corp. | Calcium sulfate hemihydrate treatment process |
| WO2010114461A1 (en) * | 2009-04-01 | 2010-10-07 | Knauf Danogips Gmbh | A coating for a construction board, a construction board comprising the coating and a method for producing the construction board |
| US11414865B2 (en) | 2012-05-31 | 2022-08-16 | Huber Engineered Woods Llc | Insulated sheathing panel |
| US11801662B2 (en) | 2018-12-27 | 2023-10-31 | Gold Bond Building Products, Llc | Cementitious panels with polymeric-film facing material |
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