Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2000-12-20
2002-02-19
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S394000, C428S395000
Reexamination Certificate
active
06348263
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to para system aramide fiber and method for producing the same.
BACKGROUND ART OF THE INVENTION
Polyparaphenylene terephthalamide fiber (hereinafter, referred to as para system aramide fiber) is a synthetic fiber having high functions such as of high strength, high modulus elasticity, high thermal resistance, non-electro-conductivity, and no rust occurrence, as well as having flexibility and lightweight property, which are characteristics of organic fibers. From these properties, it is used as a reinforcement material for a tire for a motorcar, a motorcycle and a bicycle, a timing belt for a motorcar, a conveyer and the like. Further, it is also used for reinforcing an optical fiber cable, and as a rope. Furthermore, it is also applied to a bulletproof jacket, protection clothes which are formed as working gloves and working clothes by utilizing the feature being hard to be cut against an edged tool, and clothes for fire fighting formed by utilizing the feature being hard to burn.
In these applications, nevertheless a dyeable property is required in addition to the above-described properties, it has been difficult to dye aramide fiber, because of its high crystallinity, and its minute structure due to high intermolecular force.
The following methods have been proposed so far, as methods for dyeing aramide fibers.
JP-A-SHO 50-12322 proposes a method for diffusing additives such as dye, antioxidant, ultraviolet insulation agent, and fireproofing agent in a fiber expanded by water. However, JP-A-SHO 50-12322 does not describe with respect to diffusion of all kinds of dyes into fibers, and also does not specify the conditions. Especially, it does not describe dyeing under a condition of a water content of 50% or less.
JP-A-SHO 54-59476 discloses a method for dyeing from buckling portions of a fiber after providing crimps to the fiber at 10 crimps/inch or more. Further, JP-A-HEI 2-41414 discloses a method for adding an organic pigment to a dope for spinning. JP-A-SHO 63-145412 proposes a method for introducing para oriented aramide into a process, in which the tension is relaxed, at a coagulation step immediately after spinning, thereby bringing it into contact with a dyeing solution. Further, JP-A-HEI 7-258980 proposes a method for bringing para system aromatic polyamide, whose inherent viscosity is 2.5 dl/g or less and which is expanded by water, into contact with a dyeing solution. JP-A-HEI 8-260362 discloses a method for dyeing by a cation system dye at a temperature of 130° C. or higher, while using a fiber expansion agent. JP-A-HEI 5-209372 discloses a method for dyeing a copolymerized para system aramide fiber at a temperature of 160° C. or higher by using a dispersed dye having a molecular weight of 400 or less. Furthermore, JP-A-HEI 9-87978 and JP-A-HEI 9-87979 propose a method for dyeing a para system aramide fiber under a condition of a high pressure and a temperature of 200° C. after treating it with a polar solvent such as dimethylsulfoxide.
In the method of the above-described JP-A-SHO 54-59476, however, for a high-strength and rigid para system aramide fiber, it is difficult to provide crimps at 10 crimps/inch or more, and this method is restricted for a formation of a staple. The method disclosed in JP-A-HEI 2-41414 is a proposal for a so-called originally colored spinning, and the method described in JP-A-SHO 63-145412 is a method for bringing a fiber into contact with a dye solution at a tension-free condition without winding it after spinning. In any method, a fairly large volume of production per one color is required, and the color employed is limited. In the method disclosed in JP-A-HEI 7-258980, the strength of a fiber is extremely low because of a low viscosity of the polymer, and therefore, the method cannot satisfy the feature of high strength which aramide fiber essentially has. The method disclosed in JP-A-HEI 8-260362 is a proposal for a spun yarn, which is inferior to a filamentary yarn in tensile strength and tensile elastic modulus, and therefore, it is not satisfied as a method for dyeing a filament capable of utilizing the function of a high strength and a high elastic modulus of original aramide fiber. The methods disclosed in JP-A-HEI 5-209372, JP-A-HEI 9-87978 and JP-A-HEI 9-87979 are not common, because they require special equipment such as one for recovery of a polar solvent or for high-temperature dyeing.
So far, a method for post-dyeing capable of applying various colors at a form of a filament which can maintain the features of high-strength and high-elastic modulus of aramide fiber, namely, a method for dyeing various colors in a dyeing process, capable of dyeing at respective colors individually from each other, separately and after a process in which a spun filament is once wound onto a tube-like material, has not yet been realized.
A yarn forming process for forming a filamentary yarn and a dyeing process for dyeing the yarn generally are separated from each other, and the respective processes are performed by respective technical experts using respective exclusive equipment. To satisfy severe requirements of customers as to colors of dyed textile products, it is important to break off the process once after producing fibers, and to transport the fibers to a plant for dyeing and dye the fibers in respective colors, that customers require, by technical experts for dyeing.
DISCLOSURE OF THE INVENTION
Accordingly, it is an object of the present invention to provide a para system aramide fiber which can be dyed while its properties of high strength and high modulus elasticity can be maintained, and a para system aramide fiber dyed in various colors.
To accomplish this object, the present invention takes the following ways.
(1) A dyeable polyparaphenylene terephthalamide fiber which has been wound once after spinning and has not been dyed yet, characterized in that the fiber has a tensile strength of 15 g/denier or more and a crystal size (110 direction) of 30 to 55 angstroms and has no history of a treatment drying to have a water content of 8% or less.
(2) The dyeable polyparaphenylene terephthalamide fiber according to the above-described (1), wherein the fiber has no history of a treatment drying to have a water content of 15% or less.
(3) A staple type of dyeable polyparaphenylene terephthalamide fiber, wherein the fiber according to the above-described (1) or (2) is treated to be provided with 4 to 9 crimps/25 mm, and cut at a fiber length of 20 to 150 mm.
(4) A flock type of dyeable polyparaphenylene terephthalamide fiber, wherein the fiber according to the above-described (1) or (2) is cut at a length of 0.1 to 3 mm.
(5) A dyed polyparaphenylene terephthalamide fiber, wherein the fiber according to the above-described (1) or (2) is dyed.
(6) The dyed polyparaphenylene terephthalamide fiber according to the above-described (5), wherein the fiber is dyed by a cation dye.
(7) A staple type of dyed polyparaphenylene terephthalamide fiber, wherein the staple type of polyparaphenylene terephthalamide fiber according to the above-described (3) is dyed.
(8) The staple type of dyed polyparaphenylene terephthalamide fiber according to the above-described (7), wherein the fiber is dyed by a cation dye.
(9) A flock type of dyed polyparaphenylene terephthalamide fiber, wherein the flock type of polyparaphenylene terephthalamide fiber according to the above-described (4) is dyed.
(10) The flock type of dyed polyparaphenylene terephthalamide fiber according to the above-described (9), wherein the fiber is dyed by a cation dye.
(11) A method for producing a dyeable polyparaphenylene terephthalamide fiber by a filament forming step and a filament dyeing step, performed separately from each other, the filament forming step being performed by preparing a dope for spinning from polyparaphenylene terephthalamide having an inherent viscosity (&eegr; inh) of 5 or more and a concentrated sulphuric acid, once spinning the dope in air through fine holes of a spinning die, and immediately thereaf
Hatano Takeshi
Kosuge Kazuhiko
Sakamoto Shiro
DuPont-Toray Co. Ltd.
Edwards N.
Schnader Harrison Segal & Lewis
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