Fabric (woven – knitted – or nonwoven textile or cloth – etc.) – Nonwoven fabric – Including strand or fiber material which is of specific...
Reexamination Certificate
2000-05-01
2003-05-20
Morris, Terrel (Department: 1771)
Fabric (woven, knitted, or nonwoven textile or cloth, etc.)
Nonwoven fabric
Including strand or fiber material which is of specific...
C442S060000, C442S104000, C442S168000, C442S340000, C442S341000, C442S408000, C428S151000, C428S904000
Reexamination Certificate
active
06566287
ABSTRACT:
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a non-woven fabric for artificial leather and to artificial leather produced from the same and, more specifically, to a non-woven fabric formed of fine fibers obtained from a strippable and splittable composite short fiber comprising at least two components and to artificial leather produced from the same.
PRIOR ART
In recent years, artificial leather which is a natural leather substitute has been widely used in the fields of garments, general materials and sports because its characteristic features such as lightweight and easy care have been recognized by consumers. However, artificial leather having improved softness which is the characteristic feature of natural leather and drapeability derived from a fine structure has been demanded from the market and various proposals have been made.
For example, there is proposed a process in which the fineness of a fiber forming a non-woven fabric is reduced to 0.3 denier or less. Artificial leather produced from this fiber is actually produced and marketed. When a non-woven fabric formed of fibers of 0.3 denier or less (to be referred to as “non-woven microfabric” hereinafter) is obtained simply by reducing the monofilament size of the fibers, neps or the like are formed in the carding step with the result of a reduction in process efficiency. Therefore, various processes which improve this are proposed. These conventional production processes are roughly divided into the following three groups.
As disclosed by JP-B 48-22126 (the term “JP-B” as used herein means an “examined Japanese patent publication”), the first group uses a sea-island type composite short fiber having such a cross section that a sea and many islands are formed from a sea component and an island component incompatible with the sea component by the shapes of spinning nozzles, respectively. In this process, a non-woven fabric is produced by carrying out a mechanical entangling treatment such as needle punching or contact with a jet liquid flow after the conventional production process of a non-woven fabric. Thereafter, the non-woven fabric is impregnated with an elastic polymer, or a non-woven microfabric is formed by dissolving and removing the sea component with a solvent which dissolves the sea component but not the island component before impregnation, and an artificial leather substrate is produced using this non-woven fabric as a base.
As disclosed by JP-B 48-27443, the second group uses a polymers-blended sea-island type composite short fiber obtained by mixing a sea component for forming the sea and an island component for forming islands incompatible with the sea component in the cross section of the fiber in a molten state and spinning a dispersion containing the island component dispersed in the sea component. Also in this process, like the above sea-island type composite short fiber, after a non-woven fabric is formed, the sea component is dissolved and removed with a solvent which dissolves the sea component but not the island component to produce a non-woven microfabric, and an artificial leather substrate is produced using this non-woven fabric as a base.
As disclosed by JP-A 4-65567 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), the third group uses a strippable and splittable composite short fiber having such a cross section that two different components incompatible with each other are arranged alternately several times (as side-by-side type). In this process, the strippable and splittable composite short fiber is stripped and split into fine fibers while they are mechanically entangled by contact with a jet liquid flow or the like to produce a non-woven microfabric. Thereafter, the non-woven microfabric is impregnated with an elastic polymer to produce an artificial leather substrate comprising the non-woven microfabric as a base.
As disclosed by JP-A 49-26581, 49-93663, 49-132377 and 54-96181, there is still another process in which heat shrinkability is provided to a polyester-based resin component to facilitate the stripping and splitting of a strippable and splittable composite short fiber comprising a polyamide component and a polyester-based resin component.
Suede type and nubuck type artificial leathers produced from non-woven microfabrics formed of these fibers are very soft and have a good appearance making use of the small monofilament sizes of the fibers. However, when a grain type artificial leather is produced by forming a film of an elastic polymer on the surface, it is not satisfactory because it is not so tight as natural leather and is greatly wrinkled when its surface is bent inward. The reason for this is that even when single fiber having a small fineness is formed by splitting parent fiber, it is entangled in the state of a large assembly because the fineness of the parent fiber for forming the single fiber having a small fineness is 3 to 10 denier with the result of the formation of spaces of the same size as spaces formed in a non-woven fabric formed by entangling single fiber having a large fineness of the prior art.
As described above, since the beauty of artificial leather, mainly suede type artificial leather comprising a non-woven microfabric as a base, has gained wide acceptance from consumers, great progress is being made. A grain type artificial leather has softness even when a non-woven microfabric is used and a grain layer is formed on the surface, but it lacks tightness and is easily wrinkled by bending. When it is formed into a shoe, trunk, glove or furniture, or it is used or worn, it is difficult to obtain an aesthetic appearance and the improvement of the appearance has been strongly desired from the market.
MEANS FOR SOLVING THE PROBLEM
The present inventors paid attention to the fact that the cause of bending wrinkles is the structure of a non-woven fabric formed by entangling the above assembly of fibers having a small fineness and began to study how a fiber entangled state is finely and uniformly formed in the structure of a non-woven fabric formed by entangling fibers having a small fineness and the characteristic properties of the non-woven fabric when formed. A first possible means is to use a short fiber having a small fineness. However, with this means, neps are formed in the carding step because the fiber is very fine, thereby reducing process efficiency. Therefore, the means was excluded from the list of study.
After a process for producing a non-woven microfabric from a composite short fiber from which fibers having a small fineness can be formed was studied, in consideration of the facts that a process for dissolving and removing a sea component from a sea-island type composite short fiber and a polymers-blended sea-island type composite short fiber is required and that there is the loss of a raw material which is dissolved and removed, a non-woven microfabric having an entangled structure of fibers having a small fineness formed from a strippable and splittable composite short fiber which is economically advantageous has been studied. A non-woven fabric obtained from a conventional strippable and splittable composite short fiber by a jet liquid flow contact entangling method cannot have a uniform and fine structure but a structure that stripped and split fibers having a small fineness are mostly entangled in the state of a large assembly. In the above process which uses a strippable and splittable composite short fiber comprising a heat shrinkable polyester component, the shrinkage energy of the polyester component is consumed at the time of stripping and splitting and an assembly of fibers having a small fineness is not broken because the process is aimed to facilitate stripping making use of the axial shrinkage force of the polyester component at the time of stripping and splitting. As a result, a uniform and fine structure cannot be obtained.
It is therefore a first object of the present invention to provide a non-woven fabric having such a structure that fibers having a small
Imoto Akihiro
Mimura Masahisa
Nakamura Kimio
Nitta Hideki
Ohkawa Nobuo
Befumo Jenna-Leigh
Morris Terrel
Sughrue & Mion, PLLC
Teijin Limited
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