Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
1998-12-09
2001-04-10
Krynski, William (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S395000, C428S394000, C428S373000, C428S480000
Reexamination Certificate
active
06214463
ABSTRACT:
TECHNICAL FIELD
The present invention relates to hydrophilic fibers, and cloths and filters produced by using the fibers. More specifically, it relates to hydrophilic fibers which have a high safety and durable hydrophilic property, and are useful mainly for filter materials such as a tea pack and the likes, drip absorbing materials for maintaining freshness of foods, and packaging materials for preventing dewing employed in the field of foods, and useful for wiping cloth materials and liquid filters employed in the field of industry or medical care. Further, the invention relates to cloths and filters produced by using the fibers. For brevity, the term “cloth or cloths” used in this specification includes not only cloth or cloths but also fabric or fabrics.
BACKGROUND ART
Fibers comprising a thermoplastic resin typical examples of which are polyethylene, polypropylene, and polyester have application in various fields since the fibers are easy to handle and can be processed at a comparatively low cost. Since these thermoplastic resins are hydrophobic (water absorption is lower than 1%), the fibers produced from such a resin are ready to be charged with static electricity and tend to produce various troubles when processed, for example, into non-woven fabrics. For the purpose of preventing the fibers from being charged with static electricity, or for the purpose of imparting hydrophilic property to the fibers when they are used for application, for example, in tea packs and filters, wherein fibers are required to have a hydrophilic property, such treatments as applying one of various kind of finishing agents containing a surface active agent on the surface of the fibers are being performed to adhere the finishing agent to the fiber.
In order to use such fibers to which a surface active agent is adhered in the field of foods, the surface active agent should be low in toxicity because the surface active agent will flows out when the fibers are put in water once or twice. Besides, such problems are raised that water permeability decreases and filtration resistance increases for tea packs and filters, respectively, since the hydrophilic property of the fibers is suddenly decreased due to the outflow of the surface active agent.
As the surface active agents which are small in the effluence from the fibers and can durably maintain the hydrophilic property of the fibers, sorbitan ester-ethylene oxide adducts are known. However, the sorbitan ester-ethylene oxide adducts have such a defect that the water in which the fibers or cloths having the adduct applied thereon were immersed are ready to foam or become cloudy since the adducts have a high foaming property.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide hydrophilic fibers which maintain hydrophilic property even when immersed in water, and the surface active agent flowed out of which fibers is excellent in safety and low in foaming property; and to provide cloths and filters produced by using the fibers.
As a result of diligent research conducted in succession by the present inventors to solve the problems described above, it has been found out that the expected objects can be achieved by applying an aqueous solution of a composition of a specific surface active agent as finishing agent on the fiber surface to adhere the finishing agent to the fiber, leading to accomplishment of the present invention.
The present invention is summarized as follows:
(1) A hydrophilic fiber produced by adhering 0.1 to 1.0% by weight, based on the weight of fiber, of a finishing agent comprising 20 to 90% by weight of the following composition (A) and 10 to 80% by weight of the following composition (B), to a fiber comprising one or more thermoplastic resins having a water absorption of 1% by weight or lower:
(A) a composition comprising 0 to 75% by weight of at least one compound selected from the group consisting of sorbitan esters of a fatty acid having 12 to 18 carbon atoms and 25 to 100% by weight of at least one compound selected from the group consisting of adducts of a sorbitan ester of a fatty acid having 12 to 18 carbon atoms with 5 to 20 mole of ethylene oxide;
(B) at least one compound selected from the group consisting of (a) white mineral oils, (b) diesters of a fatty acid having 12 to 18 carbon atoms with a polyethylene glycol having a molecular weight of 200 to 600, (c) diesters of a fatty acid having 12 to 18 carbon atoms with a polypropylene glycol having a molecular weight of 200 to 600, (d) pluronic type nonionic surface active agents, and (e) metal salts of an alkyl sulfonate having 8 to 16 carbon atoms.
(2) The hydrophilic fiber recited in paragraph (1) above wherein the fiber comprising one or more thermoplastic resins is a composite fiber comprising two kind of thermoplastic resins having a difference in melting point of 10° C. or more.
(3) The hydrophilic fiber recited in paragraph (1) above wherein at least one of the thermoplastic resins which form the fiber is a polyolefin resin.
(4) The hydrophilic fiber recited in paragraph (1) above wherein at least one of the thermoplastic resins which form the fiber is a polyester resin.
(5) A cloth obtained by entangling, adhering, weaving, or knitting the hydrophilic fibers defined in any one of claims
1
to
4
.
(6) A hydrophilic cloth produced by adhering 0.1 to 1.0% by weight, based on the weight of fiber, of a finishing agent comprising 20 to 90% by weight of the following composition (A) and 10 to 80% by weight of the following composition (B), to a cloth composed of fibers comprising one or more thermoplastic resins having a water absorption of 1% by weight or lower:
(A) a composition comprising 0 to 75% by weight of at least one compound selected from the group consisting of sorbitan esters of a fatty acid having 12 to 18 carbon atoms and 25 to 100% by weight of at least one compound selected from the group consisting of adducts of a sorbitan ester of a fatty acid having 12 to 18 carbon atoms with 5 to 20 mole of ethylene oxide;
(B) at least one compound selected from the group consisting of (a) white mineral oils, (b) diesters of a fatty acid having 12 to 18 carbon atoms with a polyethylene glycol having a molecular weight of 200 to 600, (c) diesters of a fatty acid having 12 to 18 carbon atoms with a polypropylene glycol having a molecular weight of 200 to 600, (d) pluronic type nonionic surface active agents, and (e) metal salts of an alkyl sulfonate having 8 to 16 carbon atoms.
(7) A filter fabricated by using the hydrophilic fiber recited in paragraph (1) above.
(8) The filter recited in paragraph (7) above wherein the fiber comprising one or more thermoplastic resins is a composite fiber comprising two kind of thermoplastic resins having a difference in melting point of 10° C. or more.
Now, the present invention will be described in more detail.
As the thermoplastic resin used as the material for the hydrophilic fibers of the present invention and having a water absorption of 1% by weight or lower, polyolefin resins and polyester resins can preferably be mentioned as example.
As the polyolefin resins, copolymers of propylene as the main component with ethylene, butene-1, or 4-methylpentene-1 in addition to polyethylenes and polypropylenes can be mentioned as example. As polyester resins, polyethylene terephthalates, polybutylene terephthalates, copolymer of ethylene terephthalate with isophthalate, and copolymerized polyetheresters can be mentioned as example.
These thermoplastic resins can singly be formed into fibers by a melt spinning method. Further, it is possible to form two thermoplastic resins selected from such thermoplastic resins as described above and having a difference in melting point of 10° C. or more into composite fibers in which the thermoplastic resins are disposed in side-by-side, concentric sheath-core, eccentric sheath-core, radially-divided, or sea-islands fashion.
Cloths and filters of the present invention can be produced from one kind of single component fibers, mixtures of single component fibers having differen
Nishijima Masaru
Ogata Satoshi
Suzuki Masayasu
Tanoue Kozo
Chisso Corporation
Fay Sharpe Fagan Minnich & McKee LLP
Krynski William
Shewareged B.
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