US5470485A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrostatically-effective air filter material
Assignee: Carl Freudenberg KG
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Filing: 1995-03-01
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Granted: 1995-11-28
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Expires: 2015-03-01
Abstract
Abstract An air filter material for intercepting dust is disclosed. The material is free of lubricants and antistatic agents, and consists of a blend of (I) polyolefin fibers and (II) polyacrylonitrile fibers that are geometrically stable. The fibers (I) are two-component polypropylene/polyethylene fibers of the core/jacket or side-by-side type, and fibers (II) are halogen-free. The fiber blend is washed during the manufacturing process after they are first combined.
Inventors
- 👤 Karl-Heinz Morweiser
- 👤 Klaus Veeser
- 👤 Harald Stini
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 02:54
CPC Classifications
B; B03; B03C; B03C3/00; B03C3/28; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/163; D; D04; D04H; D04H1/00; D04H1/40; D04H1/42; D04H1/4282; D04H1/4291; D04H1/43; D04H1/44; D04H1/46; D04H1/48; D04H1/485; D04H1/54; D04H1/541; D04H1/5412; D04H1/5414; D04H1/5418; D04H1/542; D04H1/544; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2915; Y10T428/2929; Y10T428/2931
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
50 words
An electrostatically effective air filter material, consisting of a blend of: type (I) polyolefin fibers that are two-component polypropylene/polyethylene fibers of the core/jacket or side-by-side type; and type (II) halogen-free polyacrylonitrile fibers, wherein the filter material is geometrically stable and wherein the fibers are free of lubricants and antistatic agents.
Claim 2
Dependent Claim
50 words
An electrostatically effective air filter material, consisting of a blend of: type (I) polyolefin fibers that are two-component polypropylene/polyethylene fibers of the core/jacket or side-by-side type; and type (II) halogen-free polyacrylonitrile fibers, wherein the filter material is geometrically stable and wherein the fibers are free of lubricants and antistatic agents.
Claim 3
Dependent Claim
35 words
An air filter material according to claim 1, wherein the ratio of type (I) fibers to type (II) fibers is in the range of 30:70 to 80:20, relative to a surface of the filter material.
Claim 4
Dependent Claim
16 words
An air filter material according to claim 1, wherein the fibers are thinner than 100 μm.
Claim 5
Dependent Claim
16 words
An air filter material according to claim 2, wherein the fibers are thinner than 100 μm.
Claim 6
Dependent Claim
31 words
An air filter material according to claim 1, wherein the fibers are subjected to a shaping operation selected from the group of shaping operations consisting of stamping, punching, welding, and deep-drawing.
Claim 7
Dependent Claim
31 words
An air filter material according to claim 2, wherein the fibers are subjected to a shaping operation selected from the group of shaping operations consisting of stamping, punching, welding, and deep-drawing.
Claim 8
Dependent Claim
22 words
An air filter material according to claim 1, wherein the staple lengths of the fibers is between 30 mm and 200 mm.
Claim 9
Dependent Claim
28 words
An air filter material according to claim 1, wherein the air filter material is provided as part of a laminate made from a plurality of flat formed elements.
Claim 10
Dependent Claim
28 words
An air filter material according to claim 5, wherein the air filter material is provided as part of a laminate made from a plurality of flat formed elements.
Claim 11
Independent Claim
88 words
A method for filtering out solid or liquid aerosols, comprising the steps of: mixing together (I) a quantity of polyolefin fibers that are two-component polypropylene/polyethylene fibers of the core/jacket or side-by-side type with (II) a quantity of halogen-free polyacrylonitrile fibers; washing the resulting mixture of fibers so that it is free of lubricants and antistatic agents; forming the mixture of fibers into a non-woven fabric by carding; needling the fabric and electrostatically charging the fabric; and forming the fabric into a shape appropriate for use as a filter.
Claim 12
Independent Claim
88 words
A method for filtering out solid or liquid aerosols, comprising the steps of: mixing together (I) a quantity of polyolefin fibers that are two-component polypropylene/polyethylene fibers of the core/jacket or side-by-side type with (II) a quantity of halogen-free polyacrylonitrile fibers; washing the resulting mixture of fibers so that it is free of lubricants and antistatic agents; forming the mixture of fibers into a non-woven fabric by carding; needling the fabric and electrostatically charging the fabric; and forming the fabric into a shape appropriate for use as a filter.
Claim 13
Dependent Claim
111 words
A process for manufacturing an electrostatically effective air filter material which is free of lubricants and antistatic agents comprising the steps of: mixing together (I) a quantity of heterofilament polyolefin fibers that are two-component polypropylene/polyethylene fibers of the core/jacket or side-by-side type with (II) a quantity of halogen-free polyacrylonitrile fibers; at a weight ratio between 30:70 to 80:20 for the type I fibers with respect to the type II fibers; washing the resulting mixture of fibers so that it is free of lubricants and antistatic agents; drying the fibers; forming the mixture of fibers into a non-woven fabric by carding; needling and stiffening the fabric; and thermally activating the heterofilament fibers.
Claim 14
Dependent Claim
111 words
A process for manufacturing an electrostatically effective air filter material which is free of lubricants and antistatic agents comprising the steps of: mixing together (I) a quantity of heterofilament polyolefin fibers that are two-component polypropylene/polyethylene fibers of the core/jacket or side-by-side type with (II) a quantity of halogen-free polyacrylonitrile fibers; at a weight ratio between 30:70 to 80:20 for the type I fibers with respect to the type II fibers; washing the resulting mixture of fibers so that it is free of lubricants and antistatic agents; drying the fibers; forming the mixture of fibers into a non-woven fabric by carding; needling and stiffening the fabric; and thermally activating the heterofilament fibers.
Claim 15
Dependent Claim
15 words
A process according to claim 11, wherein the fibers employed are thinner than 100 μm.
Claim 16
Dependent Claim
21 words
A process according to claim 11, wherein the staple lengths of 30 μm to 200 μm are selected for the fibers.
Claim 17
Dependent Claim
15 words
A process according to claim 11, further including the step of shaping the nonwoven fabric.
Claim 18
Dependent Claim
24 words
A process according to claim 11, further including the step of combining the air filter material with a mechanical reinforcement to form a laminate.
Claim 19
Dependent Claim
22 words
A process according to claim 11, further including the step combining the air filter material with a plurality of flat formed elements.
References Cited (Backward Citations)
US4798850A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-11-27 | 1999-05-29 | 1999-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-11-27 | 2003-05-29 | 2003-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-11-27 | 2007-05-29 | 2007-11-28 | $7700.00 | Window Closed / Lapsed |