US4311767A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Gypsum wallboard and method for producing same
Assignee: National Gypsum Properties LLC
•
Filing: 1980-02-25
•
Granted: 1982-01-19
•
Expires: 2000-02-25
Abstract
Abstract A paper-covered gypsum core wallboard made of a cover paper having on the inner surface a synthetic size of the class consisting of certain substituted succinic acid anhydrides, certain substituted glutaric acid anhydrides and the reaction product of maleic anhydride and an internal olefin, which reduces the absorption by the paper of components of the wet gypsum slurry, without affecting substantially the paper porosity, and, of prime importance, without any deleterious effect on the bond of the paper to the gypsum core, either prior to the drying of the board or after the drying of the board.
Inventors
- 👤 Arthur E. Kennedy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:20
CPC Classifications
E; E04; E04C; E04C2/00; E04C2/02; E04C2/04; E04C2/043; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31971; Y10T428/31993; Y10T428/31996
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
140 words
Paper-covered gypsum board which comprises a gypsum core and a paper cover sheet covering at least one side of said core, said paper cover sheet having a synthetic size applied to the paper surface adjacent said core, said synthetic size being of the group consisting of (1) a cyclic dicarboxylic acid anhydride corresponding to the structural formula ##STR3## wherein R is selected from the class consisting of dimethylene and trimethylene radicals and wherein R' is a long hydrophobic side chain and is selected from the class of alkyl, alkenyl, aralkyl and aralkenyl groups and (2) the reaction product of maleic acid anhydride and an internal olefin in an amount sufficient to attain in said sheet, when said board is manufactured, a Cobb value of about 0.4 to 1.0 gram as measured on the surface of said sheet adjacent said core.
Claim 2
Dependent Claim
140 words
Paper-covered gypsum board which comprises a gypsum core and a paper cover sheet covering at least one side of said core, said paper cover sheet having a synthetic size applied to the paper surface adjacent said core, said synthetic size being of the group consisting of (1) a cyclic dicarboxylic acid anhydride corresponding to the structural formula ##STR3## wherein R is selected from the class consisting of dimethylene and trimethylene radicals and wherein R' is a long hydrophobic side chain and is selected from the class of alkyl, alkenyl, aralkyl and aralkenyl groups and (2) the reaction product of maleic acid anhydride and an internal olefin in an amount sufficient to attain in said sheet, when said board is manufactured, a Cobb value of about 0.4 to 1.0 gram as measured on the surface of said sheet adjacent said core.
Claim 3
Dependent Claim
23 words
A paper-covered gypsum board according to claim 1 wherein said sheet contains about one pound of said synthetic size per ton of paper.
Claim 4
Dependent Claim
17 words
A paper-covered gypsum board according to claim 1 wherein said synthetic size is a dicarboxylic acid anhydride.
Claim 5
Dependent Claim
30 words
A paper-covered gypsum wallboard according to claim 3 wherein said dicarboxylic acid anhydride has a long hydrophobic side chain containing more than five carbon atoms, and structured as follows: ##STR4##
Claim 6
Dependent Claim
55 words
A paper-covered gypsum wallboard according to claim 1 wherein said synthetic size comprises the reaction product of maleic anhydride with an internal olefin corresponding to R.sub.x --CH.sub.2 --CH═CH--CH.sub.2 --R.sub.y wherein R x is an alkyl radical containing at least four carbon atoms and R y is an alkyl radical containing at least four carbon atoms.
Claim 7
Independent Claim
137 words
A method of making paper-covered gypsum board which comprises forming a core of cementitious gypsum slurry, laminating said core with a paper sheet having a synthetic size coated on the face adjacent said core, said synthetic size being of the group consisting of (1) a cyclic dicarboxylic acid anhydride corresponding to the structural formula ##STR5## wherein R is selected from the class consisting of dimethylene and trimethylene radicals and wherein R' is a long hydrophobic side chain and is selected from the class of alkyl, alkenyl, aralkyl and aralkenyl groups and (2) the reaction product of maleic acid anhydride and an internal olefin in an amount sufficient to attain in said sheet a Cobb value of about 0.4 to 1.0 gram as measured on the surface of said sheet adjacent said core, and drying said gypsum board.
Claim 8
Independent Claim
137 words
A method of making paper-covered gypsum board which comprises forming a core of cementitious gypsum slurry, laminating said core with a paper sheet having a synthetic size coated on the face adjacent said core, said synthetic size being of the group consisting of (1) a cyclic dicarboxylic acid anhydride corresponding to the structural formula ##STR5## wherein R is selected from the class consisting of dimethylene and trimethylene radicals and wherein R' is a long hydrophobic side chain and is selected from the class of alkyl, alkenyl, aralkyl and aralkenyl groups and (2) the reaction product of maleic acid anhydride and an internal olefin in an amount sufficient to attain in said sheet a Cobb value of about 0.4 to 1.0 gram as measured on the surface of said sheet adjacent said core, and drying said gypsum board.
Claim 9
Dependent Claim
26 words
The method according to claim 6 wherein said size is coated on said paper face at a rate of about one pound per ton of paper.
Claim 10
Dependent Claim
15 words
The method according to claim 6 wherein said synthetic size is a dicarboxylic acid anhydride.
Claim 11
Dependent Claim
27 words
The method according to claim 8 wherein dicarboxylic acid anhydride has a long hydrophobic side chain containing more than five carbon atoms, and structured as follows: ##STR6##
Claim 12
Dependent Claim
53 words
The method according to claim 6 wherein said synthetic size comprises the reaction product of maleic anhydride with an internal olefin corresponding to R.sub.x --CH.sub.2 --CH═CH--CH.sub.2 --R.sub.y wherein R x is an alkyl radical containing at least four carbon atoms and R y is an alkyl radical containing at least four carbon atoms.
References Cited (Backward Citations)
US3102064A
Cited
US3300371A
Cited
US3139373A
Cited
US3389042A
Cited
US3821069A
Cited
US3968005A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-01-18 | 1985-07-20 | 1986-01-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-01-18 | 1989-07-20 | 1990-01-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-01-18 | 1993-07-20 | 1994-01-19 | $7700.00 | Window Closed / Lapsed |