Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2001-03-14
2003-03-25
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S370000, C428S373000, C428S395000, C264S172170
Reexamination Certificate
active
06537660
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a synthetic fiber having both lightweight properties and excellent dyeability.
2. Description of the Background
Because of their excellent lightweight properties, strength and chemical resistance, polyolefin fibers are widely used in ropes, bundling yarns, filters, wipers, diapers and sanitary items, among others. In recent years, because of environmental considerations, the demand for polyolefin fibers as materials of high recyclability or as low combustion heat materials is increasing.
Although polyolefin fibers are lightweight and have good chemical resistance, they cannot be satisfactory dyed and, currently, polyolefin fibers are not widely used in clothing items. Although polyolefin fibers are used in producing items for nonclothing use, such as paper and nonwoven fabrics, they are not used in those fields of application where delicate shades or hues are demanded.
While merely colored polyolefin fibers can be obtained by incorporating a pigment into a resin composition and spinning the same, it is difficult for the fibers to take up a delicate shade or hue. To increase the variety of colors, dyeing with dyes is preferred; and therefore a number of proposals have been advanced to impart dyeability to polyolefin fibers. For example, a method has been proposed which includes subjecting a polyolefin together with a polyester or polyamide, which are dyeable, to mixed or composite spinning. With this method, dyeability is indeed improved, but because polyolefins adhere very poorly to polyesters or polyamides, interfacial peeling or color irregularities tend to occur in fibers made by this method, and this method has not been put to practical use. Further, there is a proposal according to which an ethylene/alkyl acrylate copolymer is blended with or grafted on polypropylene (JP Kohyo H1O-501309). The dyeability obtained with this method is not very satisfactory, however.
On the other hand, polyester fibers show good dyeability against disperse dyes and are thus widely utilized in both clothing and non-clothing items. However, since polyester fibers have a specific gravity of 1.38, the products produced using polyester fibers are undesirably heavy, especially when compared to textile materials made from polypropylene, which has a specific gravity of less than 1.0. That is a remaining problem.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention is to provide a fiber having excellent dyeability.
Another object of the present invention is to provide a fiber which is as lightweight as polyolefins and which has excellent dyeability.
Another object of the invention is to provide a fiber having good light fastness and washing fastness.
Another object of the present invention is to provide a fiber having excellent dyeability without impairing the lightweight property, strength and chemical resistance intrinsic in polyolefins such as polyethylene and polypropylene.
These and other objects have now been attained by the present invention, the first embodiment of which provides a fiber, which includes:
2 to 95% by weight, based on the total weight of the fiber, of at least one block copolymer, which includes:
at least one polymer block (A) that includes 50 to 100% by weight of olefinic monomer units, based on the total weight of the block copolymer; and
at least one polymer block (B) that includes 0.1 to 100% by weight of (meth)acrylic monomer units, based on the total weight of the block copolymer.
Another embodiment of the invention provides a fibrous structure, which includes the above-described fiber.
Another embodiment of the invention provides a non-woven fabric, which includes the above-described fiber.
Another embodiment of the invention provides a leather-like sheet material, which includes:
a fibrous structure which includes the above-described fiber; and
an elastomeric polymer impregnated in the fibrous structure.
Another embodiment of the invention provides a dyed article, which includes the above-described fiber and a dye.
Another embodiment of the invention provides a process for producing a fiber, which includes melt spinning a composition that includes:
of at least one block copolymer, which includes:
at least one polymer block (A) that includes 50 to 100% by weight of olefinic monomer units, based on the total weight of the block copolymer; and
at least one polymer block (B) that includes 0.1 to 100% by weight of (meth)acrylic monomer units, based on the total weight of the block copolymer;
to produce a fiber.
Another embodiment of the invention provides a composite fiber, which includes:
80 to 20% by weight of a polymer composition, based on the total weight of the fiber; and
20 to 80% by weight of a thermoplastic polymer, based on the total weight of the fiber;
wherein the polymer composition includes 2 to 95% by weight, based on the total weight of the polymer composition, of at least one block copolymer, which includes:
at least one polymer block (A) that includes 50 to 100% by weight of olefinic monomer units, based on the total weight of the block copolymer; and
at least one polymer block (B) that includes 0.1 to 100% by weight of (meth)acrylic monomer units, based on the total weight of the block copolymer.
Another embodiment of the invention provides a fibrous structure, which includes the above-described composite fiber.
Another embodiment of the invention provides a non-woven fabric, which includes the above-described composite fiber.
Another embodiment of the invention provides a dyed article, which includes the above-described composite fiber and a dye.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Various other objects, features and attendant advantages of the present invention will be more fully appreciated as the same becomes better understood from the following detailed description of the preferred embodiments of the invention.
The invention preferably relates to a fiber which includes 2 to 95% by weight of a block copolymer made from at least one polymer block (A) that includes 50 to 100% by weight of olefinic monomer units and at least one polymer block (B) that includes 0.1 to 100% by weight of (meth)acrylic monomer units. The invention also preferably relates to a composite fiber resulting from composite spinning of a composition that includes the above block copolymer and another thermoplastic polymer in a ratio of 20-80% by weight to 80-20% by weight. Other preferable embodiments of the invention include various fibrous structures and leather-like sheet materials, which include such a fiber as a constituent.
The block copolymer constituting at least part of the fiber of the invention is constituted of the polymer block (A) and polymer block (B) mentioned hereinbelow and preferably includes, for example, A-B type diblock copolymers, A-B-A type triblock copolymers and B-A-B type triblock copolymers. Among them, A-B type diblock copolymers are preferred.
In the present invention, it is important to use the block copolymer which includes the polymer block (A) and polymer block (B), as mentioned above. When a random copolymer or graft copolymer of an olefinic monomer and a (meth)acrylic monomer, for instance, is used instead of the block copolymer in accordance with the invention, the dyeability against disperse dyes may not be satisfactorily improved, or only products that have poor color fastness will be obtained.
The polymer block (A) constituting the block copolymer according to the invention contains 50 to 100% by weight, preferably 70 to 100% by weight, more preferably 80 to 100% by weight, based on the whole structural units, of olefinic monomer units. These ranges include all values and subranges therebetween, including 52, 54, 57, 63, 68, 72, 75, 78, 82, 86, 88, 93 and 95%. When this content is less than 50% by weight, the lightweight properties and other characteristics intrinsic in polyolefins will be lost and the effects described herein cannot be produced. Preferable olefinic monomer units include, among others, units derived from alipha
Inoue Ichirou
Katayama Takashi
Maekawa Kazuhiko
Nakatsuka Hitoshi
Yorimitsu Shuhei
Edwards N.
Kuraray Co. Ltd.
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