Moulded fibrous material

• US 4,149,550 A
• Filed: 07/29/1977
• Issued: 04/17/1979
• Est. Priority Date: 08/02/1976
• Status: Expired due to Term

• Current Assignee: Wiggins Teape PLC
• Original Assignee: Wiggins Teape Limited
• Inventors: Allen, Roger A., Inglis, Bruce R., Tringham, Roger W., Green, Kieron P.
• Primary Examiner(s): Kendell, Lorraine T.
• Application Number:
  US05/820,387
• Time in Patent Office: 627 Days
• Field of Search: 428/364, 428/357, 428/372, 428/373, 428/374, 428/375, 428/367, 131/266, 131/267, 131/268, 131/269, 156/180
• US Class Current: 131/341
• CPC Class Codes: A24D 3/04 Tobacco smoke filters characterised by their shape or structure
• CPC Class Codes: A24D 3/06 Use of materials for tobacco smoke filters
• CPC Class Codes: B01D 39/14 Other self-supporting filtering material ; Other filtering material non-woven fabrics in general D04H3/00
• CPC Class Codes: B01D 39/18 the material being cellulose or derivatives thereof cork or peat B01D39/1646 ; making filter paper D21F11/14
• CPC Class Codes: Y10T 428/2913 Rod, strand, filament or fiber
• CPC Class Codes: Y10T 428/2918 including free carbon or carbide or therewith [not as steel]
• CPC Class Codes: Y10T 428/2927 including structurally defined particulate matter
• CPC Class Codes: Y10T 428/2929 Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• CPC Class Codes: Y10T 428/2933 Coated or with bond, impregnation or core

Abstract

A fibrous element comprising an elongated structure having a fibrous core with the fibres arranged in random orientation, said core being stiffened and enclosed by a fibrous crust integral with the core and formed as a surface layer of greater density.

Claims

1. A fibrous element comprising an elongated structure having a fibrous core with discrete fibres arranged in random orientation, said core being stiffened and enclosed by a fibrous crust integral with the core and formed as a surface layer of greater density which also has discrete fibres arranged in a random orientation.

2. A fibrous element as claimed in claim 1 in which a higher proportion of fibres in the surface layer are orientated lengthwise than in the core.

3. A fibrous element as claimed in claim 2, which when parted under tension in a lengthwise direction exhibits substantially coniform interfaces at the point of separation.

4. A fibrous element as claimed in claim 3 in which the fibrous structure has a substantially coniform integrity but contains coniform structures which define at their peripheries the fibrous crust.

5. A fibrous element as claimed in claim 1 in which the fibrous material of the core and crust contains a proportion of stiff bulky fibres in combination with finer fibres, thus providing a structured matrix to improve the filtration characteristics and strength of the fibrous element.

6. A fibrous element as claimed in claim 5 in which the stiff bulky fibres are highly extracted alpha cellulose chemically bleached pulps containing a high degree of summerwood.

7. A fibrous element as claimed in claim 6 in which the fine fibres have a high specific surface area.

8. A fibrous element as claimed in claim 7 in which the fine fibres are taken from the group esparto, eucalyptus and cotton.

9. A fibrous element as claimed in claim 5 in which the fine fibres are present in the concentration of 40% to 50% by weight.

10. A fibrous element as claimed in claim 1 in which the fibrous material of the core and crust contain up to about 10% by weight of an additive from the group comprising kaolin, calcium carbonate, activated carbon and diatomaceous earth.

11. A fibrous element as claimed in claim 10 wherein a binder from the group comprising starch and wet strength resins is present to prevent fluffing occurring during manufacture.

12. A fibrous element as claimed in claim 11 in which the wet strength resins are from the group polyamine, and polyethylenamine.

13. A fibrous element as claimed in claim 1 wherein the surface of the element contains a coating of starch as a binder.

14. A fibrous element as claimed in claim 1 wherein a proportion of synthetic fibres is present.

15. A fibrous element as claimed in claim 14 in which the synthetic fibres are polyolefin fibres.

16. A smoke filter made from the fibrous element of claim 1.

17. The product of claim 16 wherein the smoke filter is a cigarette filter.