Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2002-11-21
2004-06-15
Edwards, Newton (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S373000, C428S374000
Reexamination Certificate
active
06749935
ABSTRACT:
This application claims the benefit of Japanese Patent Applications No. 2001-357911 and No. 2002-121720, which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1 Field of the Invention
This invention relates to a temperature-sensitive color-changeable composite fiber. More particularly it relates to a temperature-sensitive color-changeable composite fiber having superior metachromatism.
2. Related Background Art
As conventionally available resins used in cores and sheaths of composite fibers, combination of resins having like structures are used. Such resins may include polyolefin resins, as having superior core-sheath interface joining properties and being capable of providing fibers free of any possibility of separation. However, composite fibers making use of such polyolefin resins have had so insufficient surface glossiness and touch as to have a poor commercial value.
A temperature-sensitive color-changeable composite fiber is also disclosed which is made up of a thermochromic resin phase formed of a polyolefin resin containing a thermochromic material and a protective resin phase comprised of a polyester resin or a polyamide resin (U.S. Pat. No. 5,153,066).
In the above proposal, since the polyolefin resin or polyamide resin is used to form the protective resin phase, the fiber has a good glossiness and can provide a smooth touch, but has a disadvantage that color changes of the thermochromic resin phase which are caused by temperature changes may come not clearly sighted. This is due to a poor resin-to-resin adherence of the thermochromic resin phase and the protective resin phase, which causes a phenomenon of separation at the interfaces between these phases, so that the color changes of the thermochromic resin phase which are to be sighted through the protective resin phase may come not sighted because of the scattering of light caused by any gaps produced as a result of separation.
SUMMARY OF THE INVENTION
The present invention was made in order to eliminate such difficulties the conventional temperature-sensitive color-changeable composite fiber has had. More specifically, an object of the present invention is to provide a temperature-sensitive color-changeable composite fiber which can satisfy the glossiness and touch of fibers and in which color changes caused by temperature changes can clearly be sighted.
To achieve the above object, the present invention provides as a requirement a temperature-sensitive color-changeable composite fiber comprising:
a phase-(A) thermochromic resin phase formed of a polyolefin resin in which a thermochromic material and an adhesive resin having a molecular weight of 200 to 10,000 or a copolymer resin of an olefin with a unit monomer capable of forming a polymer having a solubility parameter (SP value) of 9.0 or more have been dispersed or dissolved; and
a phase-(B) resin phase selected from nylon 12, a copolymer nylon, polyhexamethylene terephthalate and a saturated aliphatic polyester;
the phase-(A) and the phase-(B) being joined to each other.
As further requirements, the adhesive resin may be at least one resin selected from a petroleum resin, a polyterpene resin, a polyisobutylene resin and an ionomer resin; the petroleum resin may be an aliphatic petroleum resin, an aromatic petroleum resin, an aliphatic-aromatic copolymer petroleum resin, a dicyclopentadiene resin, or a hydrogenated product of any of these; the unit monomer may be selected from maleic anhydride, vinyl alcohol, acrylonitrile, an acrylate and a methacrylate; the adhesive resin or the copolymer resin may be contained in the phase-(A) thermochromic resin phase in an amount of from 1% by weight to 30% by weight; the polyolefin resin may be a resin selected from a propylene resin, an ethylene-propylene copolymer resin and a mixture of an ethylene resin and a propylene resin; the polyamide resin may be contained in an amount of from 0.1% by weight to 30% by weight in the resin contained in the phase-(A) thermochromic resin phase; and the temperature-sensitive color-changeable composite fiber may be a core-sheath composite fiber comprising the phase-(A) thermochromic resin phase as a core and the phase-(B) resin phase as a sheath.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The temperature-sensitive color-changeable composite fiber of the present invention consists basically of a phase-(A) thermochromic resin phase and a phase-(B) resin phase. The phase-(A) thermochromic resin phase is formed of a polyolefin resin in which a thermochromic material and an adhesive resin having a molecular weight of 200 to 10,000 or a copolymer resin of an olefin with a unit monomer capable of forming a polymer having a solubility parameter (SP value) of 9.0 or more have been dispersed or dissolved. The phase-(B) resin phase is selected from 12-nylon, a copolymer nylon, hexamethylene terephthalate and a saturated aliphatic polyester. The phase-(A) and the phase-(B) are joined to each other.
In the foregoing, the polyolefin resin which forms the phase-(A) thermochromic resin phase may be exemplified by a polypropylene homopolymer, a polyethylene-polypropylene random copolymer, a polyethylene-polypropylene block copolymer, and a mixture of polyethylene and polypropylene. In particular, the polyethylene-polypropylene random copolymer may preferably be used, as having flexibility and an appropriate tensile strength which are required as fibers and also having a superior transparency.
As the thermochromic material contained in the phase-(A) thermochromic resin phase, a reversible thermochromic composition may preferably be used which contains three components which are an electron-donating color-developing organic compound, an electron-accepting compound and an organic compound medium capable of causing the color-developing reaction of these compounds to take place reversibly. It may specifically include reversible thermochromic compositions disclosed in U.S. Pat. No. 4,028,118 and No. 4,732,810.
The above composition changes in color at about a given temperature (color-changing point) making a border, and in the normal temperature region can only exist in any one specific state of both states before and after their color change. More specifically, these are of a type that shows what is called a small hysteresis width (&Dgr;H) on temperature/color density due to changes in temperature to cause metachromatism, in which the other state is maintained so long as the heat or cold that is required for them to come into that state is applied, but returns to the state shown in the normal temperature region once the heat or cold becomes not applied.
Also effective is one disclosed in U.S. Pat. No. 4,720,301, owned by the present assignee, which is a thermochromic color memorizable composition that shows great hysteresis characteristics to cause metachromatism, i.e., a metachromatic material of a type capable of changing in color following courses which are greatly different in shape of curves formed by plotting changes in coloring density due to changes in temperature, between a case where the temperature is raised from the side of a temperature lower than a color-changing temperature region and a case where inversely the temperature is dropped from the side of a temperature higher than the color-changing temperature region, and having a characteristic feature of capable of memorizing a state changed at a low-temperature side color-changing point or below or at a high-temperature side color-changing point, in the normal temperature region between the low-temperature side color-changing point and the high-temperature side color-changing point.
Also usable is a reversible thermochromic composition capable of developing a color upon heating, which uses an alkoxyphenol as the electron-accepting compound.
The above reversible thermochromic composition may be effective even when used as it is, but may preferably be used in the state it is enclosed in microcapsules (a microcapsule pigment). This is because such a reversible thermochromic composition can be kept to have the same composition u
Edwards Newton
Fitzpatrick ,Cella, Harper & Scinto
The Pilot Ink Co., Ltd.
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