Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2002-09-24
2004-02-17
Kelly, Cynthia H. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S364000, C428S394000, C428S395000, C264S183000, C264S184000
Reexamination Certificate
active
06692828
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to spandex fiber excellent in resistance to both chlorine and heat and manufacturing method thereof, and more particularly, to spandex fiber which has high resistance to both chlorine and heat without affecting intrinsic properties of the polyurethane polymer, and manufacturing method thereof.
2. Background of the Related Art
Spandex fiber is generally excellent in physical properties such as tensile strength, elastic recoverability, etc. and still has high rubber elasticity and therefore widely used for underwear, socks, sports apparel, etc.
Nevertheless, when washed with chlorine bleaching, spandex fiber has a considerable deterioration of physical properties in the portion of polyurethane, which is the principal component of spandex. For swimsuit made of spandex and polyamide, a contact with chlorinated water (containing 0.5 to 3.5 ppm of active chlorine) in a swimming pool also deteriorates the properties of spandex.
In an attempt to improve the resistance to chlorine-induced deterioration, the use of additives as a chlorine resisting agent has been proposed, the chlorine resisting agent being zinc oxide (U.S. Pat. No. 4,340,527), a mixture of huntite and hydromagnesite (U.S. Pat. No. 5,626,960), calcium carbonate or barium carbonate (Korean Patent Publication No. 92-3250), MgO/ZnO solid (Japanese Patent Laid-open No. 1994-81215), magnesium oxide, magnesium hydroxide or hydrotalcite (Japanese Patent Laid-open No. 1984-133248), and hydrotalcite coated with stearic acid (U.S. Pat. No. 5,447,969).
Especially, U.S. Pat. No.5,447,969 discloses the use of a hydrotalcite coated with stearic acid to prevent water absorption of the hydrotalcite and thereby to improve the problem in regard to a rise of pack pressure and yarn breakage in the spinning process. But there is almost no difference in chlorine resistance as compared with the case of using a non-coated hydrotalcite.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to a spandex fiber excellent in resistance to both chlorine and heat and manufacturing method thereof that substantially obviates problems due to limitations and disadvantages of the foregoing related art.
An object of the present invention is to provide a spandex fiber with improved resistance to both chlorine and heat.
The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a spandex fiber excellent in resistance to chlorine and heat that contains a hydrotalcite coated with melamine-based compounds, the hydrotalcite being represented by the following formula (1):
M
2+
x
Al
m
(OH)
y
(A
k−
)
z
·n
H
2
O (1)
wherein M
2+
is Mg
2+
or Zn
2+
; A
k−
is an k-valent anion; x and y are a positive number which is 2 or greater than 2 ; and Z, m and n are a positive number.
Preferably, the hydrotalcite is selected from the compounds of the following formulas (2) to (6):
Mg
4.5
Al
2
(OH)
13
CO
3
·3.5H
2
O (2)
Mg
6
Al
2
(OH)
16
CO
3
·5H
2
O (3)
Mg
8
Al
2
(OH)
20
CO
3
·6H
2
O (4)
Mg
6
Al
2
(OH)
12
(CO
3
)
3
·7H
2
O (5)
Mg
4
Al
2
(OH)
12
CO
3
·3H
2
O (6)
Preferably, the melamine-based compounds include melamine compounds, phosphor-associated melamine compounds, melamine cyanurate compounds, melamine compounds substituted with an organic compound having a carboxyl group, phosphor-associated melamine compounds substituted with an organic compound having a carboxyl group, or melamine cyanurate compounds substituted with an organic compound having a carboxyl group, which may be used alone or in combination.
Preferably, the content of the hydrotalcite coated with the melamine-based compounds in fiber is 0.1 to 10 wt. %.
Preferably, the average particle diameter of the hydrotalcite coated with the melamine-based compound is 0. 1 to 10 &mgr;m.
In another aspect of the present invention, there is provided a method for manufacturing spandex fiber excellent in resistance to chlorine and heat, the method including: coating the hydrotalcite with melamine-based compounds; adding the hydrotalcite coated with the melamine compounds to a polyurethane solution; and spinning the polyurethane solution into fiber.
Preferably, the coated amount of the melamine-based compound with respect to the hydrotalcite is 0.1 to 10 wt. %.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Hereinafter, the present invention will be described in further detail.
As a result of repeated experiments and researches, the inventors have found that spandex fiber excellent in resistance to both chlorine and heat relative to the prior art can be achieved by using a hydrotalcite coated with melamine-based compounds as a chlorine resisting agent.
When added to a polymer without being coated, however, hydrotalcite is likely to absorb water with a consequence of gellation and agglomeration. Thus a rise of pack pressure and yam breakage are caused in the process of spinning, as a result of which stabilized spinning of the yarn over a long period of time is difficult to achieve.
Accordingly, the present invention provides a spandex fiber excellent in resistance to chlorine and heat relative to the prior art by coating the hydrotalcite with heat resistant melamine-based compounds.
The added amount of the melamine-based compounds with respect to the hydrotalcite is desirably in the range of 0.1 to 10 wt. %. When the amount is below the range, the chlorine resisting agent is liable to absorb water and agglomerate while added to the polymer, thereby causing yam breakage, waved fiber formation and non-uniform yam properties. When the amount exceeds 10 wt. %, the coating effect is almost the same as in the case of the amount less than 10 wt. %.
A coating method as used herein involves adding the melamine-based compound to a solvent such as water, alcohol, ether, dioxane, etc. in an amount of 0.1 to 10 wt. % with respect to hydrotalcite, adding the hydrotalcite to the solution having the melamine-based compound, coating the hydrotalcite with the melamine-based compound at a raised temperature of 50 to 170° C. (if necessary, using a high-pressure reactor) with stirring for about 30 minutes to 2 hours, and subjecting the resultant mixture to filtering and drying. An alternative coating method is a physical mixing method that involves mixing the melamine-based compound dissolved in a solvent with hydrotalcite in a high-speed mixer and drying the mixture.
The melamine-based compound is not only used to coat the hydrotalcite but also to make the spandex fiber excellent in resistance to both chlorine and heat relative to the case of using the conventional coating material, such as stearic acid.
The melamine-based compounds as used herein include melamine compounds; phosphor-associated melamine compounds; melamine cyanurate compounds; melamine compounds substituted with an organic compound having a carboxyl group; phosphor-associated melamine compounds substituted with an organic compound having a carboxyl group; or melamine cyanurate compounds substituted with an organic compound having a carboxyl group, which may be used alone or in combination.
More specifically, the melamine compounds may include methylene dimelamine, ethylene dimelamine, trimethylene dimelamine, tetramethylene dimelamine, hexamethylene dimelamine, decamethylene dimelamine, dodecamethylene dimelamine, 1,3-cyclohexylene dimelamine, p-phenylene dimelamine, p-xylene dimelamine, diethylene trimelamine, triethylene tetramelamine, tetraethylene pentamelamine, or hexaethylene heptamelamine.
The phosphor-associated melamine compounds may include any of the above-mentioned melamine compounds associated with phosphoric acid or phosphate. Specific examples of the phosphor-associa
Kim Ji Won
Lee Dae Hwi
Lee Tae Woo
Seo Seung Won
Song Byung Su
Bell Boyd & Lloyd LLC
Gray J. M.
Hyosung Corporation
Kelly Cynthia H.
LandOfFree
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