US4505972A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Crack propagation resistant acrylic sheet
Assignee: Arkema France SA
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Filing: 1983-11-14
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Granted: 1985-03-19
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Expires: 2003-11-14
Abstract
Abstract Improved crack propagation resistant acrylic sheets are provided: These sheets are prepared by copolymerizing methyl methacrylate with minor amounts of lower alkyl (C 2 -C 4 ) methacrylates. One and one quarter inch thick sheets polymerized from a monomer mixture of about 88 weight percent methyl methacrylate and about 12 weight percent butyl methacrylate or from about 76 weight percent methyl methacrylate and about 24 weight percent ethyl methacrylate are useful as indoor and outdoor ballistic glazing materials.
Inventors
- 👤 Thomas S. Moore
- 👤 Delmas B. Pennington
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 11:37
CPC Classifications
F; F41; F41H; F41H5/00; F41H5/02; F41H5/04; F41H5/0407; B; B32; B32B; B32B17/00; B32B17/06; B32B17/10; B32B17/10005; B32B17/1055; B32B17/10743; C; C08; C08F; C08F220/00; C08F220/02; C08F220/10; C08F220/12; C08F220/14; Y; Y10; Y10S; Y10S428/00; Y10S428/911; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T428/31935
Claims Analysis
Total Claims: 27
Claim 1
Independent Claim
67 words
A solid crack propagation resistant molded acrylic material comprising a copolymer prepared from about 76 to about 94 weight percent methyl methacrylate and from about 24 to about 6 weight percent of a lower alkyl methacrylate, said alkyl group containing from 2 to 4 carbon atoms, and when said lower alkyl methacrylate is ethyl methacrylate the copolymer is prepared from at least 12 weight percent ethyl methacrylate.
Claim 2
Dependent Claim
67 words
A solid crack propagation resistant molded acrylic material comprising a copolymer prepared from about 76 to about 94 weight percent methyl methacrylate and from about 24 to about 6 weight percent of a lower alkyl methacrylate, said alkyl group containing from 2 to 4 carbon atoms, and when said lower alkyl methacrylate is ethyl methacrylate the copolymer is prepared from at least 12 weight percent ethyl methacrylate.
Claim 3
Dependent Claim
36 words
The solid crack propagation resistant molded acrylic material of claim 1 comprising a copolymer prepared from about 86 to about 94 weight percent methyl methacrylate and from about 14 to about 6 weight percent butyl methacrylate.
Claim 4
Dependent Claim
36 words
The solid crack propagation resistant molded acrylic material of claim 1 comprising a copolymer prepared from about 76 to about 88 weight percent methyl methacrylate and from about 24 to about 12 weight percent ethyl methacrylate.
Claim 5
Dependent Claim
26 words
An indoor ballistic glazing material comprising the solid crack propagation resistant molded acrylic material of claim 1 having an average thickness of at least 1,250 inches.
Claim 6
Dependent Claim
12 words
The indoor ballistic glazing material of claim 4 being a cast sheet.
Claim 7
Dependent Claim
37 words
The solid crack propagation resistant molded acrylic material of claim 2 further comprising a copolymer prepared from about 86 to about 90 weight percent methyl methacrylate and from about 14 to about 10 weight percent butyl methacrylate.
Claim 8
Dependent Claim
26 words
An indoor and outdoor ballistic glazing material comprising a cast sheet having an average thickness of about 1.250 inches prepared from the material of claim 6.
Claim 9
Dependent Claim
28 words
The solid crack propagation resistant molded material of claim 3 further comprising a copolymer prepared from about 76 weight percent methyl methacrylate and 24 weight percent ethyl methacrylate.
Claim 10
Dependent Claim
27 words
An indoor and outdoor ballistic glazing material comprising a cast sheet prepared from the copolymer of claim 8 and having an average thickness of about 1.250 inches.
Claim 11
Dependent Claim
33 words
A bullet-resisting material comprising a copolymer prepared from about 88 weight percent methyl methacrylate and about 12 weight percent butyl methacrylate, said material having an average thickness of at least about 1.250 inches.
Claim 12
Dependent Claim
33 words
A bullet-resisting material comprising a copolymer prepared from about 88 weight percent methyl methacrylate and about 12 weight percent butyl methacrylate, said material having an average thickness of at least about 1.250 inches.
Claim 13
Dependent Claim
31 words
A bullet-resisting material comprising a copolymer prepared from about 76 weight percent methyl methacrylate and about 24 weight percent ethyl methacrylate having an average thickness of at least about 1.250 inches.
Claim 14
Dependent Claim
31 words
A bullet-resisting material comprising a copolymer prepared from about 76 weight percent methyl methacrylate and about 24 weight percent ethyl methacrylate having an average thickness of at least about 1.250 inches.
Claim 15
Independent Claim
79 words
A method for improving the crack propagation resistance of a solid, molded polymethyl methacrylate article comprising copolymerizing from about 76 to about 94 weight percent methyl methacrylate with from about 24 to about 6 weight percent of a lower alkyl methacrylate, said alkyl group containing from 2 to 4 carbon atoms, and where said lower alkyl methacrylate is ethyl methacrylate the copolymer is formed from at least 12 weight percent ethyl methacrylate, and molding the copolymer into a solid.
Claim 16
Independent Claim
79 words
A method for improving the crack propagation resistance of a solid, molded polymethyl methacrylate article comprising copolymerizing from about 76 to about 94 weight percent methyl methacrylate with from about 24 to about 6 weight percent of a lower alkyl methacrylate, said alkyl group containing from 2 to 4 carbon atoms, and where said lower alkyl methacrylate is ethyl methacrylate the copolymer is formed from at least 12 weight percent ethyl methacrylate, and molding the copolymer into a solid.
Claim 17
Dependent Claim
29 words
The method of claim 12 further comprising copolymerizing from about 86 to about 94 weight percent methyl methacrylate with from about 14 to about 6 weight percent butyl methacrylate.
Claim 18
Dependent Claim
29 words
The method of claim 12 further comprising copolymerizing from about 76 to about 88 weight percent methyl methacrylate with from about 24 to about 12 weight percent ethyl methacrylate.
Claim 19
Dependent Claim
20 words
The method of claim 12 further comprising forming a cast sheet having an average thickness of at least 1.250 inches.
Claim 20
Dependent Claim
27 words
The method of claim 12 further comprising copolymerizing from about 86 to about 90 weight methyl methacrylate with about 14 to about 10 weight percent butyl methacrylate.
Claim 21
Dependent Claim
21 words
The method of claim 12 further comprising copolymerizing about 76 weight percent methyl methacrylate with about 24 weight percent ethyl methacrylate.
Claim 22
Dependent Claim
15 words
An indoor and outdoor ballistic glazing material prepared according to the method of claim 16.
Claim 23
Dependent Claim
15 words
An indoor and outdoor ballistic glazing material prepared according to the method of claim 17.
Claim 24
Independent Claim
40 words
A method for preparing a bullet-resisting solid sheet comprising copolymerizing about 88 weight percent methyl methacrylate and about 12 weight percent butyl methacrylate, and casting said copolymer into a sheet having an average thickness of at least about 1.250 inches.
Claim 25
Independent Claim
40 words
A method for preparing a bullet-resisting solid sheet comprising copolymerizing about 88 weight percent methyl methacrylate and about 12 weight percent butyl methacrylate, and casting said copolymer into a sheet having an average thickness of at least about 1.250 inches.
Claim 26
Dependent Claim
14 words
An indoor and outdoor bullet-resisting sheet prepared according to the method of claim 20.
Claim 27
Dependent Claim
16 words
An indoor, high power small arms, bullet resisting sheet formed from the material of claim 10.
References Cited (Backward Citations)
US3865619A
Cited
US4368235A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-03-18 | 1988-09-17 | 1989-03-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-03-18 | 1992-09-17 | 1993-03-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-03-18 | 1996-09-17 | 1997-03-19 | $7700.00 | Window Closed / Lapsed |