Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2001-02-08
2002-06-18
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S372000, C428S384000
Reexamination Certificate
active
06406788
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an elastic polyurethane fiber and a process for producing the same. The present invention relates, in more detail, to an elastic polyurethane fiber which hardly deteriorates in various chlorinated water environments and, particularly, which is excellent in chlorine resistance characteristics when used in swimwear in a swimming pool containing germicidal chlorine, and a process for stably producing the fiber.
BACKGROUND ART
An elastic polyurethane fiber obtained from an aromatic diisocyanate, a polyalkylene glycol and a polyfunctional hydrogen-containing compound has a high rubber elasticity, and is excellent in mechanical properties such as tensile stress and resilience, and thermal properties. Accordingly, the elastic polyurethane fiber as a stretchable functional fiber material has been widely used for such fiber products required to have stretchability as swimwear, foundation garments, stockings and sportswear.
In general, when clothing products in which an elastic polyurethane fiber is used are repeatedly washed by immersing them in a chlorine bleaching agent over a long period of time, the elastic polyurethane fiber is known to lose its elastic function. For example, when swimwear in which an elastic polyurethane fiber is used is repeatedly exposed to germicidal chlorinated water having an active chlorine concentration from 0.5 to 3 ppm, in a swimming pool or the like, the elastic function thereof is significantly impaired or yarn breakage is likely to take place. In particular, it is known that for swimwear comprising a polyamide fiber and an elastic polyurethane fiber, fading of color of dyeing tend to occur.
In order to improve the chlorine resistance of an elastic polyurethane fiber, a polyester-based elastic polyurethane fiber prepared by using an aliphatic polyester diol as a starting material has been employed. However, its chlorine resistance has been insufficient. Moreover, since an aliphatic polyester has a high biological activity, the polyester-based polyurethane has a disadvantage of being likely to be attacked by fungi. The polyester-based polyurethane therefore has the problem that the elastic function of the swimwear lowers during its use or storage and yarn breakage tends to take place.
Although an elastic polyether-based polyurethane fiber prepared by using as a starting material a polyether diol having an extremely low biological activity is not degraded by fungi, its chlorine resistance is still poorer than the polyester-based polyurethane. Various additives for improving chlorine-caused deterioration of the elastic polyether-based polyurethane fiber, namely, anti-chlorine agents have been proposed. For example, Japanese, Examined Patent Publication (Kokoku) No. 60-43444 discloses zinc oxide; Japanese Examined Patent Publication (Kokoku) No. 61-35283 discloses magnesium oxide, aluminum oxide, etc.; Japanese Unexamined Patent Publication (Kokai) No. 59-133248 discloses magnesium hydroxide, etc.; Japanese Unexamined Patent Publication (Kokai) No. 6-81215 discloses solid solution of magnesium oxide and zinc oxide.
The effects of magnesium oxide and aluminum oxide on the prevention of the chlorine-caused deterioration which are disclosed in Japanese Examined Patent Publication (Kokoku) No. 61-35283 are insignificant compared with comparative examples as shown in Table 1 on page 4 of the Patent Gazette (refer to Table 1 on page 4 of the Patent Gazette). Zinc oxide disclosed in Japanese Examined Patent Publication (Kokoku) No. 60-43444 has the problem that the elastic polyether-based polyurethane fiber markedly loses its chlorine resistance because the zinc oxide component is eluted from the fiber during dyeing under an acid condition (pH 3 to 6) and the retained zinc oxide content in the fiber significantly decreases. The use of the solid solution of magnesium oxide and zinc oxide disclosed in Japanese Unexamined Patent Publication (Kokai) No. 6-81215 and that of magnesium hydroxide, etc. disclosed in Japanese Unexamined Patent Publication (Kokai) No. 59-133248 produce little effect of improving the prevention of chlorine-caused deterioration, similarly to zinc oxide, and the effect is at an unsatisfactory level.
For swimwear comprising an elastic polyurethane fiber and a polyamide fiber, in order to prevent fading of dyeing used in the swimwear with chlorine contained in the water of a pool, the swimwear subsequent to dyeing is subjected to dye-fixation treatment with a fixation agent such as tannin. When an elastic polyurethane fiber containing a known anti-chlorine agent such as zinc oxide, magnesium oxide or a solid solution of magnesium oxide and zinc oxide is dyed under an acid condition (pH 3 to 6), the chlorine resistance of the fiber is lowered. Moreover, when dyed swimwear, etc., is subjected to dye-fixation treatment with a tannin solution or the like under an acid condition (pH 3 to 4.5), the chlorine resistance of the elastic polyurethane fiber is further lowered.
On the other hand, when these anti-chlorine agents are added to a polyurethane spinning dope or a molten polyurethane, secondary agglomeration of the agents takes place, and clogging of the spinning filter or yarn breakage during spinning increases. The use of zinc oxide having a particle size of 0.1 to 1 &mgr;m is disclosed in Japanese Examined Patent Publication (Kokoku) No. 60-43444; the use of magnesium oxide having a particle size of 5 &mgr;m or less is disclosed in Japanese Examined Patent Publication (Kokoku) No. 61-35283; the use of a solid solution of magnesium oxide and zinc oxide having a particle size of 0.05 to 3 &mgr;m is disclosed in Japanese Unexamined Patent Publication (Kokai) No. 6-81215. However, none of these known methods refer to the technologies of decreasing clogging of a spinning filter and reducing yarn breakage during spinning caused by secondary agglomeration of an anti-chlorine agent, etc.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide an elastic polyurethane fiber which hardly deteriorates in chlorinated water environments, which can be dyed under an acid condition (pH 3 to 6), and which shows excellent chlorine resistance even when dyed under an acid condition (pH 3 to 6), or when dyeing is subjected to dye-fixation treatment under an acid condition after dyeing, and a process for stably producing the elastic polyurethane fiber.
The present inventors have made the discoveries explained below. The simultaneous presence in the fiber of specific metal compound particles added as an anti-chlorine modifier to the polyurethane and a treating agent selected from fatty acids, styrene/maleic anhydride copolymers, esterified products of a styrene/maleic anhydride copolymer and phosphoric esters makes the elastic polyurethane fiber show excellent chlorine resistance regardless of whether the fiber is dyed or not, in comparison with an elastic polyurethane fiber containing the known anti-chlorine agent as mentioned above. Moreover, the treating agent shows higher chlorine resistance when it adheres to the surface of the metal compound particles. In particular, when the metal compound particles which are an anti-chlorine agent and to which the treating agent is allowed to adhere in advance prior to spinning, and contained in the spinning dope, the elastic polyurethane fiber having properties mentioned above can astonishingly be produced under stabilized spinning operation in which filter clogging and yarn breakage during spinning caused by secondary agglomeration of the metal compound particles in the spinning dope are reduced.
The present invention provides an elastic polyurethane fiber comprising metal compound particles that satisfy the following conditions (a), and a treating agent that satisfies the following conditions (b):
(a) particles of one or more metal compounds selected from the group consisting of oxides and hydroxides of one or more metals selected from Zn and Mn, and composite oxides of Zn and Mg;
(b) one or more treating agents selected from the group consisting of fatty
Doi Masanori
Yoshizato Akihiko
Asahi Kasei Kabushiki Kaisha
Edwards N.
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
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