US4612237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Hydraulically entangled PTFE/glass filter felt
Assignee: EIDP Inc
•
Filing: 1985-12-13
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Granted: 1986-09-16
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Expires: 2005-12-13
Abstract
Abstract A non-woven felt suitable for use as a filter comprised of poly(tetrafluoroethylene) and glass fibers hydraulically entangled to a supporting scrim and a process for making said felt are disclosed. The scrim is made from high temperature and chemically resistant materials.
Inventors
- 👤 Peter E. Frankenburg
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 20:20
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/08; B01D39/083; B01D39/086; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/20; B01D39/2003; B01D39/2017; B01D39/2027; B01D39/2041; B32; B32B; B32B5/00; B32B5/22; B32B5/24; B32B5/26; D; D04; D04H; D04H1/00; D04H1/40; D04H1/42; D04H1/4282; D04H1/4318; D04H1/44; D04H1/46; D04H1/492; D04H1/498; D04H3/00; D04H3/02; D04H3/04; D04H3/045; B01D2239/00; B01D2239/04; B01D2239/0457; B01D2239/06; B01D2239/0604; B01D2239/064; B01D2239/065; B01D2239/0654; B01D2239/0663; B01D2239/12; B01D2239/1225; B01D2239/1291; Y; Y10; Y10S; Y10S55/00; Y10S55/05; Y10T; Y10T428/00; Y10T428/31504; Y10T428/3154; Y10T442/00; Y10T442/10; Y10T442/102; Y10T442/109; Y10T442/121; Y10T442/133; Y10T442/143
Claims Analysis
Total Claims: 32
Claim 1
Independent Claim
58 words
A felt having a basis weight of 150-600 g/m 2 suitable for use as a filter comprising: a uniformly dispersed sheet-like structure containing 40-95 percent by weight poly(tetrafuoroethylene) fibers having a linear density per filament of 3-8 dtex, 5-60 percent by weight glass fibers having a linear density per filament of 0.2-1.5 dtex, hydraulically entangled into supporting scrim.
Claim 2
Dependent Claim
58 words
A felt having a basis weight of 150-600 g/m 2 suitable for use as a filter comprising: a uniformly dispersed sheet-like structure containing 40-95 percent by weight poly(tetrafuoroethylene) fibers having a linear density per filament of 3-8 dtex, 5-60 percent by weight glass fibers having a linear density per filament of 0.2-1.5 dtex, hydraulically entangled into supporting scrim.
Claim 3
Dependent Claim
30 words
The felt of claim 1 wherein the scrim comprises high temperature resistant and chemically resistant materials having a low shrinkage of less than about 5 percent up to 200° C.
Claim 4
Dependent Claim
16 words
The felt of claim 2 wherein the scrim comprises material substantially stable to acids and alkali.
Claim 5
Dependent Claim
12 words
The felt of claim 3 wherein the scrim comprises a polyimide material.
Claim 6
Dependent Claim
10 words
The felt of claim 3 wherein the scrim comprises poly(tetrafluoroethylene).
Claim 7
Dependent Claim
11 words
The felt of claim 3 wherein the scrim comprises glass fibers.
Claim 8
Dependent Claim
11 words
The felt of claim 3 wherein the scrim comprises stainless steel.
Claim 9
Dependent Claim
11 words
The felt of claim 3 wherein the scrim comprises polyphenylene sulfide.
Claim 10
Dependent Claim
18 words
The felt of claim 6 wherein the Percent Glass times Density of the felt is greater than 14.
Claim 11
Dependent Claim
23 words
The felt of claim 1 wherein the sheet-like structure is a web and the fiber length in the sheet-like structure is 2-10 cm.
Claim 12
Dependent Claim
20 words
The felt of claim 10 wherein the percent by weight glass in the sheet-like structure is less than 40 percent.
Claim 13
Dependent Claim
16 words
The felt of claim 11 wherein the percent fiber pull out is less than 10 percent.
Claim 14
Dependent Claim
20 words
The felt of claim 11 wherein the Taber Abrasion test is above 10 cycles per g/m 2 of basis weight.
Claim 15
Dependent Claim
25 words
The felt of claim 1 wherein the sheet-like structure is a waterleaf and the fiber length in the sheet-like structure is less than 2 cm.
Claim 16
Dependent Claim
20 words
The felt of claim 14 wherein the percent by weight glass in the sheet-like structure is less than 35 percent.
Claim 17
Dependent Claim
16 words
The felt of claim 15 wherein the percent fiber pull out is less than 20 percent.
Claim 18
Dependent Claim
21 words
The felt of claim 16 wherein the Taber Abrasion test is greater than 2 cycles per g/m 2 of basis weight.
Claim 19
Dependent Claim
18 words
The felt of claim 14 wherein the percent by weight glass in the sheet-like structure is 35-60 percent.
Claim 20
Dependent Claim
16 words
The felt of claim 18 wherein the percent fiber pull out is less than 60 percent.
Claim 21
Dependent Claim
21 words
The felt of claim 19 wherein the Taber Abrasion test is greater than 1 cycle per g/m 2 of bais weight.
Claim 22
Dependent Claim
39 words
A process for preparing the felt of claim 1 comprising: a. blending 5-60 percent by weight glass fibers with 40-95 percent by weight poly(tetrafluoroethylene); b. forming a sheet-like structure; and c. hydraulically entangling the sheet-like structure with supporting scrim.
Claim 23
Dependent Claim
12 words
The process of claim 21 wherein the sheet-like structure is a web.
Claim 24
Dependent Claim
12 words
The process of claim 21 wherein the sheet-like structure is a waterleaf.
Claim 25
Dependent Claim
29 words
The process of claim 21 wherein the scrim comprises high temperature resistance and chemically resistant materials having a low shrinkage of less than 5 percent up to 200° C.
Claim 26
Dependent Claim
16 words
The process of claim 24 wherein the scrim comprises material substantially stable to acids and alkali.
Claim 27
Dependent Claim
10 words
The process of claim 25 wherein the scrim comprises poly(tetrafluoroethylene).
Claim 28
Dependent Claim
11 words
The process of claim 25 wherein the scrim comprises glass fibers.
Claim 29
Dependent Claim
11 words
The process of claim 25 wherein the scrim comprises polyphenylene sulfide.
Claim 30
Dependent Claim
11 words
The process of claim 25 wherein the scrim comprises stainless steel.
Claim 31
Dependent Claim
12 words
The process of claim 25 wherein the scrim comprises a polyimide material.
Claim 32
Dependent Claim
21 words
The process of claim 26 further comprising heat setting on a tenter frame for at least two minutes at 230°-325° C.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-09-15 | 1990-03-17 | 1990-09-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-15 | 1994-03-17 | 1994-09-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-15 | 1998-03-17 | 1998-09-16 | $7700.00 | Window Closed / Lapsed |