Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – Reshaping running or indefinite-length work
Patent
1981-07-22
1984-02-21
Lowe, James B.
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
Reshaping running or indefinite-length work
26 186, B29C 1700, D06C 2100
Patent
active
044329261
DESCRIPTION:
BRIEF SUMMARY
This invention relates to the longitudinal compressive treatment of flexible textile and other webs, e.g. woven, knitted and non-woven fabrics, paper, foil and film.
Such treatment methods and machines are known and used for improving web properties such as softness, cover, stretchability, drape etc.; machines which can accomplish such improvements are described, for example, in U.S. Pat. Nos. 3,260,778 and 3,810,280. Heretofore, however, it has not been possible satisfactorily to improve or impart directional web properties (e.g. stretch) both in and across the machine direction; attempts to obtain or improve such two-way properties have generally necessitated sequentially applying two separate treatments and have been commercially unsuccessful.
The present invention provides a method and apparatus by which a two-way property can be improved in or imparted to a flexible web in a single operation. Particularly preferred applications of the invention impart two-way stretch to the web in a single machine pass.
According to the invention there is provided a method for the longitudinal compressive treatment of a flexible web, in which the web is continuously driven longitudinally into and through a retarding treatment zone defined by and between a pair of opposed surfaces at least one of which is stationary and rough and retardingly engages the web, the retarding force applied to the web over at least a part of the length of the retarding treatment zone oscillating across the width of the zone so that the treatment improves or provides a directional property of the web in both the longitudinal and transverse directions. For performing this method, the invention also provides apparatus for the longitudinal compressive treatment of a flexible web, the apparatus comprising a retarding treatment zone defined by closely spaced opposed surfaces at least one of which is stationary for retardingly engaging a web passing through the zone, and drive means for continuously driving a flexible web longitudinally into and through the retarding treatment zone, the roughness of said one surface over at least a portion of the length of the retarding treatment zone oscillating across the width of the zone; a modification of this apparatus comprises a retarding treatment zone defined by closely opposed surfaces at least one of which is stationary for retardingly engaging a web passing through the zone, and drive means for continuously driving a flexible web longitudinally into and through the retarding treatment zone, the said one surface being rough at least over its downstream end which terminates at a non-rectilinear transverse edge so that the retarding force applied in operation by the rough surface portion oscillates across the width of the retarding treatment zone.
Preferably the web is driven into the retarding treatment zone by a drive surface onto which the web is pressed by a confining surface. In some cases the drive surface forms also a moving surface of the retarding treatment zone, the said one stationary surface extending thereover and effecting the retardation; in others the drive surface delivers the web between a pair of stationary surfaces either or both of which may be roughened.
In order for the advantages of the present invention to be achieved, it is essential that the retarding force or surface roughness should both increase and decrease across the width of the retarding treatment zone. The value preferably oscillates a plurality of times across the width of the treatment zone, most preferably several times; in these cases, the oscillation is usually between substantially the same maxima and substantially the same minima, though this is not essential. The variation across the treatment zone may be continuous, or it may be incremental--e.g. with abrupt changes between rough and smooth surface portions alternating across the treatment zone.
The invention is illustrated, by way of example only, in the accompanying drawings, in which:
FIG. 1 is a very simplified schematic side elevation view of a known longi
REFERENCES:
patent: 3100925 (1963-08-01), Messinger
patent: 3260778 (1966-07-01), Walton
patent: 3476644 (1969-11-01), Krehnbrink
patent: 3810280 (1974-05-01), Walton et al.
patent: 3869768 (1975-03-01), Walton et al.
van Tilburg, administrator by Yolande Eve
van Tilburg, deceased Jan
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