US4722858A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fire-retardant sheet material
Assignee: DuPont Canada Inc
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Filing: 1986-06-26
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Granted: 1988-02-02
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Expires: 2006-06-26
Abstract
Abstract A fire-retardant sheet material, the manufacture thereof and a fire-retardant polymer composition are disclosed. The sheet is manufactured from a composition of polyethylene, 55 to 75% by weight of the composition of alumina trihydrate and/or magnesium hydroxide, and optionally zinc borate and/or calcium carbonate, at least 2% by weight of the composition being in the form of a graft copolymer with an ethylenically unsaturated carboxylic acid or anhydride. The composition has a melt index of 0.05 to 4.0 dg/min. In an embodiment, the graft copolymer has a shear viscosity at 200° C. and a shear rate of 400 sec -1 that is not more than 50% of that of the polyethylene. The sheet material may be used for, in particular, ceiling tile. In embodiments of the composition, 60 to 90% by weight may be alumina trihydrate and/or magnesium hydroxide, and optionally zinc borate and/or calcium carbonate.
Inventors
- 👤 David A. Harbourne
- 👤 Evelyn M. Lundhild
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 14:32
CPC Classifications
C; C08; C08K; C08K3/00; C08K3/18; C08K3/20; C08K3/22; C08K3/24; C08K3/26; C08K3/38; C08L; C08L23/00; C08L23/02; C08L23/04; C08L23/06; C08L23/08; C08L23/0807; C08L23/0815; C08L23/10; C08L23/12; C08L23/14; C08L23/18; C08L23/20; C08L2205/00; C08L2205/02; C08L2205/03; C08L2205/035; C08L51/00; C08L51/06
Claims Analysis
Total Claims: 33
Claim 1
Independent Claim
220 words
A fire-retardant sheet material having a thickness of at least 250 μm, said sheet material having been formed from a composition comprising: (a) 10 to 45% by weight of the composition of a polyolefin selected from the group consisting of: (i) homopolymers of ethylene and butene, (ii) copolymers of ethylene with at least one hydrocarbon alpha-olefin having 3 to 10 carbons, (iii) graft copolymers formed by grafting 0.2 to 2% by weight of at least one of an ethylenically unsaturated carboxylic acid or derivative thereof onto a hydrocarbon polymer, said hydrocarbon polymer being a polymer of at least one of ethylene and butene having a melt index of less than 100 dg/min., and (iv) mixtures thereof, with the proviso that at least 2% by weight of the composition is said graft copolymer; and (b) 55 to 90% by weight of the composition of a filler, said filler comprising 40 to 100% by weight of at least one of alumina trihydrate and magnesium hydroxide, and 0-60% by weight of at least one of zinc borate and calcium carbonate; said composition having a melt index in the range of 0.05 to 4.0 dg/min.; and said fire-retardant sheet having a Flame Spread Index of less than 150 and a Smoke Density of less than 300, as measured by the procedures of ASTM E-84.
Claim 2
Dependent Claim
220 words
A fire-retardant sheet material having a thickness of at least 250 μm, said sheet material having been formed from a composition comprising: (a) 10 to 45% by weight of the composition of a polyolefin selected from the group consisting of: (i) homopolymers of ethylene and butene, (ii) copolymers of ethylene with at least one hydrocarbon alpha-olefin having 3 to 10 carbons, (iii) graft copolymers formed by grafting 0.2 to 2% by weight of at least one of an ethylenically unsaturated carboxylic acid or derivative thereof onto a hydrocarbon polymer, said hydrocarbon polymer being a polymer of at least one of ethylene and butene having a melt index of less than 100 dg/min., and (iv) mixtures thereof, with the proviso that at least 2% by weight of the composition is said graft copolymer; and (b) 55 to 90% by weight of the composition of a filler, said filler comprising 40 to 100% by weight of at least one of alumina trihydrate and magnesium hydroxide, and 0-60% by weight of at least one of zinc borate and calcium carbonate; said composition having a melt index in the range of 0.05 to 4.0 dg/min.; and said fire-retardant sheet having a Flame Spread Index of less than 150 and a Smoke Density of less than 300, as measured by the procedures of ASTM E-84.
Claim 3
Dependent Claim
51 words
The sheet material of claim 1 in which the graft copolymer is formed by grafting at least one of an ethylenically unsaturated carboxylic acid and an anhydride thereof onto a homopolymer of ethylene or a copolymer of ethylene and at least one C 4 -C 10 hydrocarbon alpha-olefin, or admixtures thereof.
Claim 4
Dependent Claim
33 words
The sheet material of claim 2 in which the polyolefin is a homopolymer of ethylene or a copolymer of ethylene and at least one C 4 -C 10 hydrocarbon alpha-olefin, or mixtures thereof.
Claim 5
Dependent Claim
26 words
The sheet material of claim 3 in which the composition comprises 25 to 45% by weight of polyolefin and 55 to 75% by weight of filler.
Claim 6
Dependent Claim
19 words
The sheet material of claim 4 in which the acid is maleic acid and the anhydride is maleic anhydride.
Claim 7
Dependent Claim
14 words
The sheet material of claim 5 in which the sole polyolefin is graft copolymer.
Claim 8
Dependent Claim
40 words
The sheet material of claim 5 in which the polyolefin is a blend of graft copolymer and at least one of a homopolymer of ethylene and a copolymer of ethylene and at least one C 4 -C 10 hydrocarbon alpha-olefin.
Claim 9
Dependent Claim
28 words
The sheet material of claim 7 in which the sheet material has a Flame Spread Index of less than 25 and a Smoke Density of less than 50.
Claim 10
Dependent Claim
24 words
The sheet material of claim 8 in which the polymers of ethylene have densities in the range of 0.890 to 0.965 g/cm 3 .
Claim 11
Dependent Claim
24 words
The sheet material of claim 8 in which the polymers of ethylene have densities in the range of 0.935 to 0.955 g/cm 3 .
Claim 12
Dependent Claim
19 words
The sheet material of claim 7 in which the polyolefin contains 2.0 to 20% by weight of graft copolymer.
Claim 13
Dependent Claim
55 words
The sheet material of claim 10 in which the polymer of ethylene blended with the graft copolymer is 45 to 75% by weight of polymer of ethylene having a melt index of 3 to 10 dg/min. and 25 to 45% by weight of polymer of ethylene having a melt index of 30 to 80 dg/min.
Claim 14
Dependent Claim
22 words
The sheet material of claim 5 in which the polyolefin has a melt index in the range of 5 to 30 dg/min.
Claim 15
Dependent Claim
23 words
The sheet material of claim 5 in which the graft copolymer has a melt index in the range of 5 to 100 dg/min.
Claim 16
Dependent Claim
13 words
The sheet material of claim 1 in the form of a ceiling tile.
Claim 17
Dependent Claim
13 words
The sheet material of claim 8 in the form of a ceiling tile.
Claim 18
Dependent Claim
23 words
The sheet material of claim 1 in which the thickness of the sheet material is in the range of 400 to 6000 μm.
Claim 19
Dependent Claim
172 words
A composition comprising: (a) 10 to 45% by weight of the composition of a polyolefin selected from the group consisting of: (i) homopolymers of hydrocarbon alpha-olefins having 2 to 4 carbon atoms, (ii) copolymers of ethylene with at least one hydrocarbon alpha-olefin having 3 to 10 carbon atoms, (iii) graft copolymers formed by grafting 0.2 to 2% by weight of at least one of an ethylenically unsaturated carboxylic acid or derivative thereof onto a hydrocarbon polymer, said hydrocarbon polymer being a polymer of at least one of ethylene and butene, and (iv) mixtures thereof, with the proviso that at least 2% by weight of the composition is said graft copolymer; and ,p1 (b) 55 to 90% by weight of the composition of a filler, said filler comprising 40 to 100% by weight of at least one of alumina trihydrate and magnesium hydroxide, and 0 to 60% by weight of at least one of zinc borate and calcium carbonate; said composition having a melt index in the range of 0.5 to 4.0 dg/min.
Claim 20
Dependent Claim
172 words
A composition comprising: (a) 10 to 45% by weight of the composition of a polyolefin selected from the group consisting of: (i) homopolymers of hydrocarbon alpha-olefins having 2 to 4 carbon atoms, (ii) copolymers of ethylene with at least one hydrocarbon alpha-olefin having 3 to 10 carbon atoms, (iii) graft copolymers formed by grafting 0.2 to 2% by weight of at least one of an ethylenically unsaturated carboxylic acid or derivative thereof onto a hydrocarbon polymer, said hydrocarbon polymer being a polymer of at least one of ethylene and butene, and (iv) mixtures thereof, with the proviso that at least 2% by weight of the composition is said graft copolymer; and ,p1 (b) 55 to 90% by weight of the composition of a filler, said filler comprising 40 to 100% by weight of at least one of alumina trihydrate and magnesium hydroxide, and 0 to 60% by weight of at least one of zinc borate and calcium carbonate; said composition having a melt index in the range of 0.5 to 4.0 dg/min.
Claim 21
Dependent Claim
32 words
The composition of claim 18 in which the polyolefin is a homopolymer of ethylene or a copolymer of ethylene and at least one C 4 -C 10 hydrocarbon alpha-olefin, or mixtures thereof.
Claim 22
Dependent Claim
16 words
The composition of claim 18 in which the polyolefin is a copolymer of ethylene and propylene.
Claim 23
Dependent Claim
11 words
The composition of claim 18 in which the polyolefin is polybutene.
Claim 24
Dependent Claim
50 words
The composition of claim 19 in which the graft copolymer is formed by grafting at least one of an ethylenically unsaturated carboxylic acid and an anhydride thereof onto a homopolymer of ethylene or a copolymer of ethylene and at least one C 4 -C 10 hydrocarbon alpha-olefin, or mixtures thereof.
Claim 25
Dependent Claim
18 words
The composition of claim 22 in which the acid is maleic acid and the anhydride is maleic anhydride.
Claim 26
Dependent Claim
13 words
The composition of claim 23 in which the sole polyolefin is graft copolymer.
Claim 27
Dependent Claim
39 words
The composition in claim 23 in which the polyolefin is a blend of graft copolymer and at least one of a homopolymr of ethylene and a copolymer of ethylene and at least one C 4 -C 10 hydrocarbon alpha-olefin.
Claim 28
Dependent Claim
23 words
The composition of claim 25 in which the polymers of ethylene have densities in the range of 0.890 to 0.965 g/cm 3 .
Claim 29
Dependent Claim
23 words
The composition of claim 25 in which the polymers of ethylene have densities in the range of 0.935 to 0.955 g/cm 3 .
Claim 30
Dependent Claim
18 words
The composition of claim 25 in which the polyolefin contains 2.0 to 20% by weight of graft copolymer.
Claim 31
Dependent Claim
54 words
The composition of claim 27 in which the polymer of ethylene blended with the graft copolymer is 55 to 75% by weight of polymer of ethylene having a melt index of 3 to 10 dg/min. and 25 to 45% by weight of polymer of ethylene having a melt index of 30 to 80 dg/min.
Claim 32
Dependent Claim
21 words
The composition of claim 23 in which the polyolefin has a melt index in the range of 5 to 30 dg/min.
Claim 33
Dependent Claim
22 words
The composition of claim 23 in which the graft copolymer has a melt index in the range of 5 to 100 dg/min.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-02-01 | 1991-08-03 | 1992-02-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-02-01 | 1995-08-03 | 1996-02-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-02-01 | 1999-08-03 | 2000-02-02 | $7700.00 | Window Closed / Lapsed |