Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2000-11-06
2001-10-02
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S375000, C428S394000
Reexamination Certificate
active
06296933
ABSTRACT:
TECHNICAL FIELD
This invention relates to a hydrophilic fiber having an excellent hydrophilic property and good in stability of the hydrophilic property with lapse of time. More particularly, this invention relates to a hydrophilic fiber hardly deteriorating hydrophilic performances especially even when the hydrophilic fiber is kept in environments at high temperatures and high humidities for a long period.
BACKGROUND ART
Proposals have hitherto been made for various kinds of polyolefin-based fibers such as fibers comprising a polyolefin alone or conjugate fibers in which the polyolefin is exposed to a part or all of the fiber surfaces. Products such as nonwoven fabrics or woven or knitted fabrics comprising the fibers have widely been utilized in fields for household uses such as makeup puffs, wet tissues or draining bags, medical uses such as base fabrics for fomentations, agricultural and civil engineering uses such as hydroponic mats or draining mats, clothing uses or the like such as underwear.
In these fields of uses, the excellent hydrophilic property is frequently required for the above the products. Because of this, proposals have heretofore been made for methods of applying a hydrophilic treating agent to the polyolefin-based fiber surfaces, for example, a method of applying a treating agent containing a polyoxyalkylene-modified silicone to the fiber surfaces (Japanese Unexamined Patent Publication No. 1-148879), a method of applying a treating agent containing an alkylolamide type compound and a polyoxyalkylene-modified silicone to the fiber surfaces (Japanese Unexamined Patent Publication No. 1-148880) and a method of applying a treating agent containing a polyglycerol ester of a fatty acid to the fiber surfaces (Japanese Unexamined Patent Publication No. 2-216265).
Fibers obtained by the methods or the products comprising said fibers have excellent hydrophilic performances at the beginning. Nevertheless, there are problems in that the hydrophilic performances are easily deteriorated when the fibers or the products are stored for a long period and the deterioration is marked at the time of storing in warehouses or the like where the atmosphere is especially subject to high temperatures and high humidities. Furthermore, there are problems of cases where fiber surface friction is reduced and the carding speed cannot be improved when the above polyoxyalkylene-modified silicone or the polyglycerol-based ester of the fatty acid is applied.
The present invention, therefore, is made in consideration of the problems encountered in the above prior art. An object of the present invention is to provide a hydrophilic fiber hardly deteriorating the hydrophilic performances even when kept in severe atmospheres at high temperatures and high humidities and excellent in stability with lapse of time.
DISCLOSURE OF THE INVENTION
As a result of intensive investigations conducted to achieve the object, the present inventors et al. have found that a treating agent containing a specific polyether polyester block copolymer and/or a polyoxyalkylene alkyl ether and a metal alkenylsuccinate together is applied to provide a fiber retaining the excellent hydrophilic property even when stored at high temperatures and high humidities for a long period. As a result of further elaborated investigation, the present invention has been attained.
According to the present invention, there is provided the hydrophilic fiber which is a fiber characterized in that the ratio of the perimeter occupied by a polyolefin to the whole perimeter of the fiber cross section is 30% or above and the hydrophilic property of fiber is 30 seconds or below and the retention of the hydrophilic property of the fiber with lapse of time is 90% or above, which properties are respectively defined as follows:
Hydrophilic Property of Fiber:
The interior of a pipe made of polymethyl methacrylate and having an inside diameter of 25 mm, an outside diameter of 30 mm and a pipe length of 25 mm is stuffed with 5.0 grams of fibers so as not to protrude the fibers. Said pipe is floated on 1,000 cc of softened water in a container having a caliber of 105 mm &phgr; and filled with the water at 30° C., allowed to stand and once sunk to the bottom. The fibers are then taken out of the interior of the pipe and air-dried at normal temperature. The operations are repeated four times, and the number of seconds required for the pipe from floating on the water to sinking to the bottom of the container is subsequently measured in the fifth operation to provide the hydrophilic property of the fiber.
Retention of hydrophilic property of fiber with lapse of time:
When the hydrophilic property of the fiber before the treatment with lapse of time (at a temperature of 40° C. and a relative humidity of 80% for 30 days) measured according to the above method is a
1
and the hydrophilic property of the fiber after the treatment with lapse of time is b
1
, the reciprocal (indicated by %) of b
1
/a
1
is defined as the retention of hydrophilic property of the fiber with lapse of time.
According to the present invention, there is further provided the hydrophilic fiber which is a fiber characterized in that the ratio of the perimeter occupied by a polyolefin to the whole perimeter of the fiber cross section is 30% or above and a treating agent containing the component (A) and/or the component (B) described below in an amount of 15 to 95% by weight based on the active components of the treating agent and the component (C) described below in an amount of 5 to 40% by weight based on the active components of the treating agent in an amount of 0.05 to 5% by weight based on the weight of said fiber is applied to the surface of said fiber.
(A) a polyether polyester block copolymer comprising a polyether block composed of polyoxyalkylene units and a polyester block composed of polyoxycaproyl units.
(B) a higher alkyl ether of a polyoxyalkylene glycol having polyoxyethylene units and
(C) a metal alkenylsuccinate.
BEST MODE FOR CARRYING OUT THE INVENTION
The fiber to be an object of the present invention may be a fiber comprising a polyolefin fiber alone or a blend spun fiber with other polymers or a conjugate fiber (a core-sheath type, a side-by-side type, an alternately arranged type or an island-in-sea type or the like) if the polyolefin occupies at least 30%, preferably 50% or above of the perimeter to the whole perimeter of the fiber cross section.
For example, polyethylene, polypropylene, polybutene-1, polypenene-1 and a random copolymer or a block copolymer thereof or a polyolefin-based polymer copolymerized with at least one or more kinds selected from unsaturated carboxylic acids such as methacrylic acid, acrylic acid, maleic acid, fumaric acid, crotonic acid and itaconic acid and derivatives thereof such as an ester and an acid anhydride can be cited as the preferably used polyolefin. Moreover, a graft copolymer in which at least one kind of the above unsaturated carboxylic acids or derivatives thereof is grafted onto the above polyolefin-based polymer can be cited. Among the polymers, polyethylene is preferred.
When the above fiber is a conjugate fiber or a blend spun fiber, a polyester, for example, polyethylene terephthalate or polybutylene terephthalate and a polyamide, for example, nylon 6 or nylon-66 can be cited as the polymer which can be blended or conjugated with the polyolefin.
Among the fibers, a conjugate fiber comprising a polyester such as polyethylene terephthalate or polybutylene terephthalate having a higher melting point than that of the polyolefin and fiber-forming properties and good in mechanical characteristics and the polyolefin is especially preferred because the conjugate fiber can be utilized as a heat bonding fiber and bulkiness, resistance to permanent set in fatigue, elasticity, hand and the like of the finally obtained products such as a nonwoven fabric are good.
Although the conjugate weight ratio or blend weight ratio of the polyolefin to other polymers is not especially limited, the weight ratio of the polyolefin is preferably wi
Goda Hironori
Tashiro Mikio
Edwards N.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Teijin Limited
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