Patent CA1103869A successfully refreshed from Google Patents.
CA1103869A
Expired / Lapsed
CA
⏱️ 0.0 years remaining
Selfbonded nonwoven fabrics from heterofils with high density polyethylene sheath
Assignee: Fiber Industries Inc
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Filing: 1978-03-10
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Granted: 1981-06-30
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Expires: 1998-03-10
Abstract
Abstract ABSTRACT OF THE DISCLOSURE Disclosed are selfbonded nonwoven fabrics eminently suitable for civil engineering applications such as unpaved road underlay material. The fabrics comprise at least 70 weight percent of sheath/core heterofilaments having a core of isotactic polypropylene in which the sheaths are high density polyethylene in an amount of 5 to 30 weight percent of the heterofilaments. Up to 30 weight percent of other fibers, natural or synthetic, may be included in the fabric. The claimed fabrics have outstanding combinations of strength, fatigue resistance, and tear resistance; and are far superior in this regard than corresponding fabrics based upon low density polyethylene sheaths. The method of preparation includes melt spinning substantially concentric foregoing heterofilaments; drawing the heterofilaments at a ratio in the range of 2-6; pneumatically laying the filaments to form an unbonded web; and selfbonding the web under pressure and at a fabric temperature of from 120 to 155.degree.C.
Inventors
- 👤 Hazael E. Booker
- 👤 Barrie L. Davies
- 👤 Alfred J. Hughes
- 👤 Charles J. Shimalla
Bibliographic Details
Application Number
—
Jurisdiction
CA
Data Source
google_patents
Last Synchronized
2026-11-04 16:06
CPC Classifications
D; D01; D01F; D01F8/00; D01F8/04; D01F8/06; D04; D04H; D04H3/00; D04H3/08; D04H3/14; B; B29; B29K; B29K2023/00; B29K2023/04; B29K2023/06; Y; Y10; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2929; Y10T442/00; Y10T442/60; Y10T442/637; Y10T442/641; Y10T442/69
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
183 words
WHAT WE CLAIM IS: 1. An improved selfbonded nonwoven fabric having a weight of at least 40 gm/meter2 and consisting essentially of fibrous non-particulate material and comprising at least seventy percent, based on total weight of fibers in the fabric, of drawn continuous heterofilaments comprising at least two fiber- forming synthetic polymer components arranged in sheath/core manner, the core being isotactic polypropylene physically entrapped in a network of bonded sheaths having a melting point at least 10.degree.C lower than that of the core, wherein the improve- ment comprises: said sheath is high density polyethylene having a solid state density in the range from 0.930 to 0.965 gm/cc and having a melt flow index from 1 to 50 as measured by ASTM D-1238; said high density polyethylene comprises from 5 to 30 weight percent of said heterofilaments; and said fabric has an Elmendorf tear strength (ASTM D 1424), T, of at least 6 lb and a normalized grab tensile strength, G, of at least 120 lb (ASTM D-1117) for a 140 gm/meter2 fabric and the value of the product TxG is at least 1,200.
Claim 2
Dependent Claim
23 words
The fabric of claim l wherein said sheaths comprise 10 to 20 weight percent of said heterofilaments and TxG is at least 1,800.
Claim 3
Dependent Claim
25 words
The fabric of claim 2 wherein said heterofilaments comprise at least 98 percent by weight of said fabric and TxG is at least 2,300. -23-
Claim 4
Dependent Claim
20 words
The fabric of claim 1 wherein said high density polyethylene has a solid state density of at least 0.940 gm/cc.
Claim 5
Dependent Claim
22 words
The fabric of claim 1 wherein said high density polyethylene has a melt flow index in the range from 1 to 20.
Claim 6
Dependent Claim
22 words
The fabric of claim 4 wherein said high density polyethylene has a melt flow index in the range from 1 to 20.
Claim 7
Dependent Claim
43 words
The fabric of claim 1 wherein said fabric is area-selfbonded and has an Elmendorf tear strength of at least 10 lb and a normalized grab tensile strength of at least 150 lb and an elongation of at least 50 percent at maximum stress.
Claim 8
Dependent Claim
25 words
The fabric of claim 1 having a test track life, L, of at least 1,000 cycles to failure for a fabric of about 140 gm/meter2.
Claim 9
Dependent Claim
11 words
The fabric of claim S wherein L is at least 1500.
Claim 10
Dependent Claim
25 words
The fabric of claim 1 having a weight up to 200 gm/meter ; and comprising filaments having deniers in the range from 1 to 20.
Claim 11
Dependent Claim
224 words
An improved process for preparing a fabric having an Elmendorf tear strength (ASTM D-1424), T, of at least 6 lb. and a normalized grab tensile strength, G, of at least 120 lb. (ASTM D-1117) for a 140 gm/meter fabric, and the value of the product T x G being at least 1,200 by a process including the steps of melt spinning substantially concentric sheath/core hetero- filaments, drawing the spun filaments, pneumatically laying the drawn filaments to form an unbonded web, and thereafter bonding the web by the application of heat and pressure via nip rolls to form a selfbonded nonwoven fabric without using solvents that are relatively non-volatile at the bonding conditions, wherein the improvement comprises: (i) melt spinning sheath/core heterofilaments, wherein said sheath is high density polyethylene having a solid state density in the range from 0.930 to 0.965 gm/cc and having a melt flow index from 1 to 50 as measured 24 by ASTM D-1238, and wherein said high density polyethylene comprises from 5 to 30 weight percent of said heterofilament; (ii) drawing said spun heterofilaments at a draw ratio within the range 2.0 to 6.0, at a temperature up to 120.degree.C; and (iii) bonding said unbonded web at a fabric temperature of from 120 to 155.degree.C. at a nip stress in the range of 50 to 140 pounds per square inch.
Claim 12
Dependent Claim
15 words
The process of claim 11 which comprises continuously processing said heterofilaments into selfbonded nonwoven fabric.
Claim 13
Dependent Claim
19 words
The process of claim 11 which comprises drawing said spun hetero- filaments at a draw ratio less than 5.
Claim 14
Dependent Claim
19 words
The process of claim 12 which comprises drawing said spun hetero- filaments at a draw ratio less than 3.6.
Claim 15
Dependent Claim
23 words
The process of claim 11 which comprises melt spinning concentric sheath/core filaments comprising sheath from 10 to 20 weight percent of said heterofilaments.
References Cited (Backward Citations)
No citation records indexed.
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