Woven or knit fabric and process for producing the same

Abstract

A woven or knit fabric comprising air-jet interlacing spun yarns comprising polyester fibers of low titanium oxide content; a woven or knit fabric comprising air-jet interlacing spun yarns comprising polyester staple fibers obtained by graft polymerization of a hydrophilic compound; a woven or knit fabric comprising air-jet interlacing spun yarns comprising side by side crimped staple fibers; a woven or knit fabric comprising air-jet interlacing spun yarns comprising low-shrinkage staple fibers and copolymerized polyester staple fibers; and a process for producing these. A woven or knit fabric of polyester staple fibers that is bulky, excelling in moisture retention, lightweightness, water absorptivity, quick dryability, etc. and exhibits excellent anti-pilling properties can be obtained.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a woven or knit fabric and a process for producing the same, more specifically, a woven or knit fabric comprising air-jet interlacing spun yarn, and a process for producing the same. [0002] The present invention includes four aspects of first to fourth ones. [0003] The first aspect of the present invention relates to a woven or knit fabric comprising an air-jet interlacing spun yarn which comprises a polyester staple fiber in which said fabric can exhibit ultraviolet shielding effect, anti-transparency and anti-pilling property by an unprecedented mechanism. Furthermore, this aspect relates to a woven or knit fabric which comprises a polyester staple fiber, can exhibit anti-pilling property, and gives excellent quick-drying property even if no special modified polyester is used. [0004] The second aspect relates to a woven or knit fabric comprising an air-jet interlacing spun yarn which comprises a polyester staple fiber ...

AI Technical Summary

Benefits of technology

[0060] The polyester fiber in the first aspect can have a sufficient rigidity (tension or stiffness), which is equal to 2.0 dtex of a round cross section fiber, because of a large rigidity resulting from the cross sectional shape of the fiber, when the fineness of the polyester fiber is from 1.1 to 1.5 dtex. Therefore, the number of constituent filaments of the spun yarn can be increased in comparison with the conventional fibers having the same yarn count. As a result, the yarn strength and effects of the fiber for reflecting ultraviolet rays and blocking the transmission of visible light can be made high. The fiber in the first aspect also has advantageous effects of weakening the interminglement property of naps and improving the anti-pilling property because of the large rigidity of the fiber.

[0061] In the polyester staple fiber in the first aspect of the present invention, the number of crimps is appropriately from 8 to 20 / 25 mm. As the crimp number increases, the bulkiness and diffuse reflection on the cloth surface increases. The crimp number is preferably 10 / 25 mm or more. The cut length of the fiber can be from 32 mm to a burr cut, and may be appropriately selected in accordance with applications. In general, it is preferred that the length is not too long, and a preferable range thereof is from 32 to 51 mm from the viewpoint of the number of naps of the spun yarn, the interminglement degree of the naps, the texture and the quality of the yarn.

[0062] When the above-mentioned polyester staple fiber is spun, the fiber is made into high-speed air-jet interlacing spun yarn not by ring-spinning but by open-end or bundle spinning. The yarns of these types are different from ring-spun yarn, and have an effect for restraining yarn naps on the basis of their structure. However, such a structure is unavoidably hardened. It is therefore desired to render spinning conditions in the invention conditions giving no damage to the texture, bulkiness and anti-pilling property of spun yarn and avoid a low spinning-out speed under a high air pressure, which increases the interlacement degree and hardens the texture.

[0063] The number of naps of the spun yarn spun-out in the first aspect is such that the number of naps having a length of at least 1 mm is at least 30 and less than 350, and the number of naps having a length of at least 3 mm is less than 15, each per 10 meters of yarn length. It is preferred that the requirements that these nap numbers are less than 300 and 10 or less, respectively, are simultaneously satisfied. When the spun yarn in which the fiber cross sectional shape and the fineness thereof are specified is prepared by high-speed air jet, as performed in the present invention, the spun yarn having a small number of naps can be obtained. When the respective nap numbers are 350 or more and 15 or more, a sufficient anti-pilling property cannot be obtained, in particular, for a bulky and loose structure such as a smooth or pile structure. Thus, the case is not preferred. If the number of naps having a length of at least 1 mm is less than 30, the spun yarn has a high interlacement degree and a small fineness. Thus, the anti-pilling property increases but the bulkiness is poor and the cloth thereof has a hard texture. Therefore, such a yarn is not preferred. As a result, the ultraviolet shielding rate which is a target of the present invention lowers, and the transmittance of visible light increases unfavorably.

[0064] When at least the above-mentioned polyester spun yarn is used in the woven or knit fabric of the first aspect, it is possible to produce a polyester-fiber-containing woven or knit fabric having a transmittance of 40% or less to visible light having wavelengths of 380 to 780 nm, a shielding ratio of 84% or more against ultraviolet rays having wavelengths of 280 to 400 nm and an anti-pilling property of at least class 3, according to the A method in JIS L 1076. At this time, it is allowable to subject the polyester fiber to mixed-spinning, filament-mixing, mixed-twisting, mixed-weaving, or mixed-knitting with other fiber to form a structure in which the polyester fiber is used at a larger ratio in the cloth surface region, while the polyester fiber can be used alone.

[0065] To dye the woven or knit fabric of the first aspect, a conventional dyeing process is conducted after scouring in the same manner as other polyester fibers. For ordinary polyester fibers, high-pressure dyeing at 120 to 130° C. is adopted. About cation-dyeable modified polyester, a dyeing from normal-pressure dying to high-pressure dyeing at 98 to 120° C. is adopted. In the present invention, the woven or knit fabric may be finished without using any ultraviolet absorber together, while an ultraviolet absorber may be used together in a smaller amount than usual. As usual, the woven fabric may be subjected to a singeing or shearing treatment before or after the dyeing, or subjected to a light alkali treatment after singeing and then dyed, thereby improving the cloth quality, anti-pilling property and texture thereof.

Problems solved by technology

In general, however, the full-dull fiber having a titanium oxide content of 3.0% by weight or more causes severe abrasion of guides, thread guides, reeds, etc., induces napping and thread breaking, and has poor process-passage property and a limit to color-developability.

However, the composite fiber is expensive and has an instable quality.

The method of giving V absorbance by post-processing has drawbacks that the texture is hardened and costs increase.

However, in such a modified polyester fiber, in particular, an organic sulfonic acid group-containing copolymer polyester fiber, metal salts easily precipitate in the spinning thereof even when the fiber is in the form of a conventional fiber with a round cross section.

Thus, the spinning performance thereof is not good.

Spinning thereof into a yarn having a modified cross section is rather difficult.

Furthermore, such a modified polyester fiber has a drawback that the fiber is poor in spinnability since the fiber has weak fiber strength.

Furthermore, there are difficulties such that processing control is complicated in order to keep a constant quality in the step of dyeing.

When a treating solution to be used is in a strongly acidic pH range, for example, a pH of 3 to 4, in the dyeing process of such a modified polyester fiber, it is difficult to control a change in the pH of the solution in the processing and a variation between batches into minimum values.

If the control is insufficient, the cloth easily becomes brittle or discolored.

Thus, the practical strength of the cloth or the quality thereof deteriorates, so that the product value is remarkably damaged.

Cloth having a fiber structure required to be dyed at a high temperature for a long time in order to obtain the anti-pilling property is disadvantageous from the viewpoint of costs.

This is very uneconomical.

However, this method has a drawback that a harder texture is given than ring spun yarn because of the structure thereof.

That is, graft-polymerization-processed polyester fibers have drawbacks such as decrease in physical properties of dyed products thereof, in particular, decrease in the strength in humidity and wrinkles, a large dimensional change, and a slimy texture.

However, those proposals also have problems, such as instability of the form of the fiber, due to swelling at the time of washing or of water-absorption, deterioration in dyeing quality, low hygroscopicity, and costs for spinning.

Thus, in the actual situation, such fibers are hardly made practicable for clothing.

For such a reason, it is impossible to perform the mixed-spinning or mixed-weaving or knitting thereof with a material having no alkali resistance, such as silk, wool, acrylic fiber, Promix, rayon, or spandex.

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