Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Reexamination Certificate
2001-11-16
2003-09-09
Edwards, N. (Department: 1774)
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
C428S398000, C428S395000
Reexamination Certificate
active
06617024
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a hollow shrinkable fiber that has good shrinkability as well as being excellent in terms of bulkiness, a lightweight feeling and warmth retention, and is suitable for manufacturing pile products.
BACKGROUND ART
In general, hollow fibers have various special features such as having body, being bulky with low apparent density, and having good warmth retention and water absorption properties. The use of hollow fibers in pile products has thus frequently been experimented with. A common pile product is a stepped pile comprising guard hairs and down hairs. A method commonly adopted for manufacturing such a stepped pile is to use non-shrinkable fibers as the guard hair fibers and shrinkable fibers as the down hair fibers, and to carry out heat treatment during the pile processing so that the shrinkable fibers are shrunk and a height difference is produced between the guard hairs comprising the non-shrinkable fibers and the down hairs comprising the shrinkable fibers. Relatively thick fibers are used as the guard hair fibers, and moreover this part of the pile is not required to be shrinkable, and hence there are many cases of hollow fibers being used as the guard hair fibers. However, in a pile product, the number of guard hairs is generally lower than the number of down hairs, and hence the overall bulkiness of the pile product tends to be determined mainly by the bulkiness of the part in which the down hairs are closely gathered. The desired texture, bulkiness and lightweight feeling of a pile product therefore cannot be realized merely by using hollow fibers as the guard hairs. There are thus calls for hollow fibers that are sufficiently thin and shrinkable as to be usable as down hairs. However, the fineness of the fibers used as the down hairs in pile products is 10 dtex or less, generally 2 to 7 dtex, and conventionally it has been difficult to manufacture hollow fibers that are both that thin and satisfy the other properties required of down hair fibers. For example, in the past many acrylic fibers having a single hollow structure, i.e. a single void in the fiber cross section, have been proposed. However, there has been a problem in that, if one attempts to obtain a sufficient void ratio with such a single hollow structure, then the fiber becomes weak due to the reduction in the thickness of the skin part (also called the shell part), which is the outer peripheral part in the fiber cross section, and hence under external pressure the fiber is squashed and does not recover, resulting in it being impossible to achieve the original functions of the hollow fibers, namely bulkiness and a lightweight feeling. To resolve this problem, in Japanese Patent Application Laid-open No. H7-90721, a method is proposed in which a plurality of substantially independent void parts are formed with a uniform spacing therebetween in the fiber cross section, thus obtaining a high void ratio. However, in this method, a modified sheath-core conjugate nozzle is used, leading to problems of industrial productivity being poor and the manufacturing cost being high. Moreover, methods of manufacturing hollow fibers by adding a blowing agent have been disclosed in Japanese Patent Application Laid-open No. S58-149313 and Japanese Patent Application Laid-open No. S62-78210. However, with these methods, there are problems in that there is unevenness in the position of formation and shape of the hollow portion, leading to a drop in colorability and inadequate realization of functions of the hollow fibers such as bulkiness and a lightweight feeling.
An object of the present invention is to resolve the above problems, and to provide a hollow shrinkable fiber for pile having a hollow form similar to that of natural fur, capable of recovering easily after the hollow portion thereof has been squashed under external pressure, having properties such as bulkiness, a lightweight feeling and warmth retention not achievable conventionally, and capable of being used as down hairs in a pile product, along with a method of manufacturing this hollow shrinkable fiber, and a pile product manufactured using the hollow shrinkable fiber.
DISCLOSURE OF THE INVENTION
A hollow shrinkable fiber for pile according to the present invention comprises a synthetic fiber, has a marrow-like or network-like hollow portion comprising a large number of voids in a core part in the fiber cross section, has a void ratio in the fiber cross section of 10 to 50%, and has a dry heat shrinkage percentage of at least 15%. The synthetic fiber preferably comprises a polymer containing a copolymer of acrylonitrile and a halogen-containing vinyl monomer.
Moreover, a method of manufacturing a hollow shrinkable fiber for pile according to the present invention is characterized by carrying out wet spinning of a copolymer of acrylonitrile and a halogen-containing vinyl monomer, and subjecting the wet fiber thus obtained to steam treatment and drying treatment, and then to heat treatment to form a hollow portion in the fiber. It is preferable for the solvent content of the fiber to be reduced to 5 wt % or less through the steam treatment, for the liquid content of the fiber to be made to be 5 to 50 wt % through the drying treatment, and for drawing treatment to be carried out after the heat treatment. Moreover, it is preferable for the heat treatment to be carried out at a temperature in the range 120 to 180° C., and for the fiber to be elongated by a factor of 1.1 to 2.3 at a temperature in the range 90 to 150° C. during the drawing treatment. Moreover, when the fiber obtained through the above-mentioned method is crimped, it is preferable to carry out the crimping by heating to a temperature 1 to 10° C. below the glass transition temperature of the fiber.
The hollow shrinkable fiber for pile of the present invention as described above is suitable for use as the down hairs of a pile product.
Following is a more detailed description of the present invention. The hollow shrinkable fiber of the present invention comprises a synthetic fiber. There are no particular limitations on this synthetic fiber, with examples including an acrylic fiber, a polyamide fiber, a polyester fiber, a polyolefin fiber, a vinyl chloride fiber, a vinylidene chloride fiber and a polyvinyl alcohol fiber. However, from the viewpoint of the product quality and texture of a pile product suitable for use as artificial fur or in stuffed toys or the like, an acrylic fiber is particularly preferable. As such an acrylic fiber, one comprising a copolymer of 30 to 80 wt % of acrylonitrile and 20 to 70 wt % of a monomer copolymerizable with acrylonitrile is preferable. Examples of such a monomer copolymerizable with acrylonitrile include, for example, acrylic acid, methacrylic acid, vinyl chloride, vinylidene chloride, vinyl esters such as vinyl acetate, vinylpyrrolidone, vinylpyridine and alkyl-substituted derivatives thereof, acrylic acid esters, methacrylic acid esters, acrylic acid amides, methacrylic acid amides and monoalkyl- or dialkyl-substituted derivatives thereof, and styrenesulfonic acid, methallylsulfonic acid and metal salts and amine salts thereof. Out of these monomers, to make the fiber fire-resistant, it is preferable to use a halogen-containing vinyl monomer. Vinyl chloride or vinylidene chloride is preferable as this halogen-containing vinyl monomer.
When it is said that there is a hollow portion in the fiber cross section in the present invention, what is meant is that there are one or more voids. In fact, the fiber of the present invention has, as the hollow portion, a marrow-like or network-like hollow portion comprising a large number of voids in a core part of the fiber cross section. This fiber cross section having a marrow-like or network-like hollow portion in the core part thereof is similar to the cross section of a hair in the natural fur of an animal such as a mink or a sable. What is meant by such a fiber cross section is that a large number of voids of different shapes are formed irregularly as in bone marrow or a
Harada Satoru
Sudo Shin
Brinks Hofer Gilson & Lione
Edwards N.
Kaneka Corporation
LandOfFree
Hollow shrinkable fiber for pile and manufacturing method... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Hollow shrinkable fiber for pile and manufacturing method..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Hollow shrinkable fiber for pile and manufacturing method... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3000899