US20070243783A1 - Conjugated Stretch Yarn, Gloves and Stretch Fabric with Openwork Pattern

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Abstract

Description

Claims

US20070243783A1

Publication number: US20070243783A1
Application number: US11/660,914
Authority: US
Inventors: Tetsuo Kotani; Yoshihiro Matsui; Yuji Hamaguchi; Mitsuo Miyajima; Yoshinobu Ohie; Masumi Goto
Original assignee: Toyobo Co Ltd
Current assignee: Toyobo Co Ltd
Priority date: 2004-09-03
Filing date: 2005-08-30
Publication date: 2007-10-18
Also published as: WO2006025357A1

A composite elastic yarn includes a polyolefin-based elastic fiber and a polyolefin-based inelastic fiber. A cross-linked polyolefin-based elastic fiber, for example, is employed as the polyolefin-based elastic fiber, and a high molecular-weight polyethylene fiber having a weight average molecular weight of at least 10×10⁵, for example, is employed as the polyolefin-based inelastic fiber. Such a composite elastic yarn is suitable for use as a glove material. The yarn may be used to produce a stretchable fabric with a watermark-like pattern including a cross-linked polyeolefin-based elastic fiber and an inelastic fiber, and having a watermark-like pattern produced by complete or incomplete removal of the inelastic fiber with partial burn-out printing.

REFERENCE TO RELATED APPLICATIONS

This is a national stage application under 35 USC 371 of International Application No. PCT/JP2005/015712, filed Aug. 30, 2005, which claims priority from Japanese Patent Application Nos. 2004-256844 and 2004-343995, filed Sep. 3, 2004, and Nov. 29, 2004, respectively, the entire disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to a composite elastic yarn with excellent chemical resistance and lightfastness, suitable for application to objects where durability is required, such as swimsuits, underwear, outerwear, diaper covers, sanitary products, outdoor products like tents, and industrial materials.
The present invention further relates to a cut-resistant glove which has excellent chemical resistance, lightfastness, and quick-drying properties, and is suitably used when handling iron plates with sharp edges or burrs; dealing with glass; engaging in dangerous work using knives, such as the processing of meat and cutting of large fish; and the like.
The present invention also relates to a stretchable fabric with a watermark-like pattern having high stretchability, and a manufacturing method therefor.

BACKGROUND OF THE INVENTION

Composite elastic yarns are widely used in swimsuits, leotards, underwear, outerwear, diaper covers, stretchable parts of sanitary products, tent sheets and the like. Conventional composite elastic yarns are covered yarns wherein a general-purpose inelastic filament yarn, such as those made of polyester or polyamide, covers a polyurethane elastic core yarn.
Although polyurethane elastic fibers have high stretchability, their chemical resistance and weatherability are significantly inferior compared with general-purpose yarns. For this reason, sufficient durability cannot be achieved when polyurethane elastic fibers are used in garments which are to be subjected to industrial cleaning involving chlorine sterilization; in swimming suits; and in materials which are exposed outdoors, such as car sheets. In order to improve chemical resistance and weather resistance of polyurethane elastic yarns, attempts at adding various additive agents thereto have been made. However, the nature of polyurethane elastic yarns remains substantially unchanged, and such polyurethane elastic yarns cannot be used especially under severe conditions (see, for example, patent document 1 and patent document 2).
Polyester fibers and polyamide fibers, which are used as inelastic fibers in composite elastic yarns, have chemical resistance and weatherability superior to those of polyurethane elastic fibers. However, these fibers are inappropriate for use as a material that is exposed to harsh environments, such as prolonged outdoor exposure or industrial cleaning with chlorine or other chemicals, because they hydrolyze and/or turn yellow under such conditions.
An example of a suitable application for composite elastic yarns is use as a glove material. Excellent cut resistance is required in gloves which are used when handling iron plates with sharp edges or burrs; dealing with glass; and engaging in dangerous work using edged tools such as knives, including the processing of meat and cutting of large fish. Known cut-resistant gloves are those made from yarns of aramid fibers, metal fibers, glass fibers, and the like. However, the use of gloves made of metal fiber yarns is limited due to the poor flexibility of metal fiber yarns and resulting difficulties in knitting, and also due to the electrically conductive nature thereof. Glass fibers may break in a glove, and the broken ends of the fibers occasionally project from the inner surface of the glove and stick into the hand. Aramid fibers are prone to lose their strength by contact with strong acid or strong alkali, and further, if exposed to natural light, the fibers are discolored and/or their abrasion resistance is decreased.
High-tenacity polyethylene fibers are also employed as cut-resistant glove materials. Although high-tenacity polyethylene fibers do not exhibit the above-described defects, because these fibers are poor in stretchability, the stretchability of the knitted fabric of a glove obtained therefrom is imparted only by its knitting structure. Stretchability of the glove is thus occasionally insufficient for some uses; the glove cannot be easily put on or taken off, and also, the adherence thereof to the skin may be inadequate.
Composite yeans comprising a polyurethane elastic yarn as a core yarn have been developed in an attempt to improve the stretchability of high-tenacity polyethylene fibers. However, as mentioned above, the chemical resistance and weatherability of polyurethane elastic yarns are far worse than those of general-purpose yarns. When a glove is made thin and light using such a high-tenacity polyethylene fiber so as to enhance wearing comfort, the exposure of the core yarn, composed of a polyurethane elastic fiber, becomes great. As a result, the adverse characteristics of polyurethane elastic fibers as described above significantly degrade the physical properties of the glove.
Quick-drying properties are required in gloves for use in activities using water and in outdoor leisure activities, because wet gloves give a strong feeling of discomfort to the wearer and also undermine workability. However, conventional gloves do not possess a quick-drying nature.
As described above, a cut-resistant glove which provides a comfortable fit and has excellent chemical resistance, weatherability, and quick-drying properties has not yet been achieved.
In recent years, there has been a high demand for designs on underwear, swimsuits and the like, and it has been accordingly desired to apply burn-out printing to stretchable fabrics from which these products are made.
A well-known example of a burn-out printing method is opal finishing. Opal finishing is a method wherein a fabric is first obtained as a union fabric or union knit containing an acid-resistant fiber, such as silk fibers, polyamid-based fibers and polyester-based fibers, and a vegetable fiber which is easily carbonized by acid, such as cotton fibers and rayon fibers. The obtained fabric is then printed with a carbonizing paste made of sulfuric acid, aluminium sulfate or the like, and the vegetable fiber at the printed portion is then carbonized and accordingly removed, thereby forming a watermark-like pattern. According to one conventional technique of this method, for example, an union fabric or union knit is made by weaving or knitting a polyester-based fiber having relatively high acid resistance with a cellulose fiber having poor acid resistance, the fabric or knit thus obtained is processed with acid, and the cellulose fiber is thereby burnt out, resulting in the formation of a watermark-like design on the fabric (patent document 3). Another opal finishing method is known for giving a watermark-like pattern to a fabric made of different kinds of polyester fibers having different degrees of alkali solubility (patent document 4).
As mentioned above, as materials for stretchable fabrics, covered yarns are widely used which are obtained by covering a polyurethane elastic core yarn with a general-purpose inelastic filament yarn made of polyester, polyamide or the like. However, watermark-like pattern formation by opal finishing is not possible on such a fabric because, as with the above-described general-purpose inelastic filament yarns, polyurethane elastic fibers have poor acid resistance. Moreover, polyurethane fibers easily turn yellow and thus are not suitable as materials for fabrics on which to form a watermark-like pattern.

- [Patent document 1] JP 2001-081632 A
- [Patent document 2] JP 1994-081215 A
- [Patent document 3] JP 2002-61070 A
- [Patent document 4] JP 1993-263375 A

SUMMARY OF THE INVENTION

The present invention aims to solve the above-described problems. The first object of the invention is to provide a composite elastic yarn with excellent chemical resistance and weather resistance.
The second object of the invention is to provide a cut-resistant glove with high resistance to chemicals and weathering.
The third object of the invention is to provide a stretchable fabric with a watermark-like pattern, and a manufacturing method therefor.
[Means for Solving the Problem]
(i) When an elastic fiber and an inelastic fiber in a composite elastic yarn are both polyolefin-based fibers, such a composite elastic yarn is highly resistant to chemicals and weathering. A cross-linked polyolefin-based fiber is preferably employed as such an elastic fiber.
(ii) When the inelastic fiber in such a composite elastic yarn is for example a high-tenacity polyethylene filament, a composite elastic yarn with extremely high tenacity is provided. A glove made of a fabric comprising such a composite elastic yarn ensures a comfortable fit and demonstrates excellent cut resistance, chemical resistance, and weather resistance. Furthermore, a glove manufactured using such a composite yarn has quick-drying properties.

- (iii) When a fabric is obtained by weaving or knitting a composite elastic yarn made of an elastic yarn comprising a cross-linked polyolefin fiber and an inelastic yarn not comprising any polyolefin fiber, because cross-linked polyolefin fibers are highly resistant to chemicals, a watermark-like pattern can be formed on such a fabric by dissolving the inelastic yarn by opal finishing.

The present invention has been accomplished based on these findings, and provides composite elastic yarns and so forth as described below.

- Item 1. A composite elastic yarn comprising a polyolefin-based elastic fiber and a polyolefin-based inelastic fiber.
- Item 2. A composite elastic yarn according to Item 1, wherein the polyolefin-based elastic fiber is a cross-linked polyolefin-based elastic fiber.
- Item 3. A composite elastic yarn according to Item 1, wherein the polyolefin-based inelastic fiber is a high-molecular-weight polyethylene fiber having a weight average molecular weight of at least 10×10⁵.
- Item 4. A composite elastic yarn according to Item 3, wherein the high-molecular-weight polyethylene fiber is a high tenacity multifilament fiber with a tenacity of 20 cN/dtex or more and an resistance of incipient tension of 200 cN/dtex or more.
- Item 5. A composite elastic yarn according to Item 1, comprising 1 to 50 wt. % of the polyolefin-based elastic fiber.
- Item 6. A composite elastic yarn according to Item 1, which is a covered yarn formed by covering the polyolefin-based elastic fiber with the polyolefin-based inelastic fiber.
- Item 7. A glove partially or wholly composed of a woven fabric or knitted fabric comprising the composite elastic yarn of Item 1.
- Item 8. A glove according to Item 7, wherein a portion comprising the composite elastic yarn of Item 1 contains at least 30 wt. % of the composite elastic yarn.
- Item 9. A method for manufacturing a glove, comprising weaving or knitting the composite elastic yarn of Item 1.
- Item 10. Use of the composite elastic yarn of Item 1 as a material for gloves.
- Item 11. Use of the composite elastic yarn of Item 1 for manufacturing gloves.
- Item 12. A stretchable fabric with a watermark-like pattern, the stretchable fabric comprising a cross-linked polyolefin-based elastic fiber and an inelastic fiber, and having a watermark-like pattern produced by complete or incomplete removal of the inelastic fiber with partial burn-out printing.
- Item 13. A stretchable fabric according to Item 12, wherein the inelastic fiber is at least one kind of natural fiber selected from the group consisting of cotton fibers, hemp fibers, kenaf fibers, natto(fermented soybean) fibers, soy protein fibers, wool fibers, silk fibers, cashmere fibers, and mohair fibers.
- Item 14. A stretchable fabric according to Item 12, wherein the inelastic fiber is at least one kind of chemical fiber selected from the group consisting of rayon fibers, cuprammonium rayon fibers, acetate fibers, promix fibers, polylactic acid fibers, polyester-based fibers, polyamide-based fibers, polyolefin-based fibers, and acrylic fibers.
- Item 15. A stretchable fabric according to Item 12, wherein the inelastic fiber comprises at least one kind of natural fiber selected from the group consisting of cotton fibers, hemp fibers, kenaf fibers, fermented soybean fibers, soy protein fibers, wool fibers, silk fibers, cashmere fibers, and mohair fibers; and at least one kind of chemical fiber selected from the group consisting of rayon fibers, cuprammonium rayon fibers, acetate fibers, promix fibers, polylactic acid fibers, polyester-based fibers, polyamide-based fibers, polyolefin-based fibers, and acrylic fibers.
- Item 16. A stretchable fabric according to Item 12, wherein the burn-out printing is opal finishing.
- Item 17. A stretchable fabric according to Item 12, comprising 3 to 20 wt. % of the cross-linked polyolefin-based elastic fiber.
- Item 18. A method for manufacturing a stretchable fabric with a watermark-like pattern, comprising applying partial burn-out printing to a fabric comprising a cross-linked polyolefin-based elastic fiber and an inelastic fiber, thereby completely or partially removing the inelastic fiber of a processed portion of the fabric to make a watermark-like pattern.

In the composite elastic yarn of the present invention, a polyolefin-based fiber is employed for elastic and inelastic fibers, and accordingly, excellent chemical resistance and weatherability are provided. Furthermore, when, for example, a high-molecular-weight polyethylene fiber or like high tenacity fibers are used as an inelastic fiber, the resulting composite yarn as a whole has extremely high tenacity.
The composite elastic yarn of the present invention is thus especially suitable as a material for gloves that are used for handling sharp-edged tools or like activities that might cause injuries. Materials conventionally employed for cut-resistant gloves include aramid fibers, metal fibers, glass fibers and the like. However, gloves produced with these materials have problems such as difficulties in knitting, inconveniences caused by conductivity, and the danger that fibers might break and pierce the hand. In this regard, gloves produced from the composite elastic yarn of the present invention are advantageous as the fibers therein have excellent flexibility which leads to an ease in knitting, possess electrical insulating properties, and do not easily break.
Furthermore, the present invention provides a stretchable fabric having a watermark-like pattern thereon, which has not been achieved before. More specifically, the stretchable fabric of the invention comprises an elastic fiber and an inelastic fiber, and the elastic fiber is a cross-linked polyolefin-based fiber which is highly resistant to chemicals; due to such a structure, the watermark-like pattern is formed thereon by destroying the inelastic fibers with a burn-out printing method. Unlike urethane-based elastic fibers, cross-linked polyolefin-based fibers do not yellow easily, and thus a watermark-like design with high transparency can be maintained over long-term use. The stretchable fabric of the invention is of beautiful appearance and has excellent stretchability, and hence is suitable for a wide range of uses, including applications to underwear and sportswear.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described in more detail hereinafter.
(I) Composite Elastic Yarn
The composite elastic yarn of the present invention comprises a polyolefin-based elastic fiber and a polyolefin-based inelastic fiber.
As polyolefin-based fibers are highly resistant to chemicals and weathering, fabrics obtained by weaving or knitting the composite elastic yarn of the invention do not easily discolor, and furthermore, the initial fabric properties can be maintained even under harsh conditions, such as exposure to outdoor conditions or to industrial cleaning using chemicals. Moreover, because polyolefin-based fibers have low densities, a stretchable fabric obtained therefrom is lightweight even when thick. Furthermore, as polyolefins are hydrophobic materials, the composite elastic yarn and stretchable fabric comprising the same of the invention allow quick and easy drying.
Although the form of the composite elastic yarn of the invention is not limited, in terms of cut resistance of the resulting fabric, a covered yarn wherein an elastic fiber is uniformly covered with an inelastic fiber is preferable. Such a covered yarn can be manufactured with a covering machine, or alternatively, it may also be produced by drafting an elastic yarn and at the same time plying and twisting it with an inelastic fiber.
The proportion of elastic fiber in the composite elastic yarn of the present invention is usually 1 wt. % or more, preferably 5 wt. % or more, and more preferably 10 wt. % or more. The upper limit of the proportion of elastic fiber is usually 50 wt. % or less, and preferably 30 wt. % or less. The specified range can achieve sufficient stretchability and recoverability, along with practically sufficient tenacity.
An “elastic fiber” as used herein signifies a fiber having an elasticity generally accepted as being rubber elasticity, such as, for example, a fiber wherein, after 50% elongation is applied (i.e., when stretched to 1.5 times), at least 50% of the elongation is recovered.
Examples of such polyolefin-based elastic fibers include cross-linked polyolefin-based elastic fibers. Cross-linked polyolefins are obtainable by cross-linking of substantially linear olefins, and their branch points are substantially uniformly distributed over the main chain. Such cross-linked polyolefins can be produced by chemical cross-linking using radical initiators, coupling agents and/or the like, after polymerization of olefin-based monomers. Cross-linking may also be formed, after polymerization, by irradiation of energetic beams such as electron beams, β-rays, and γ-rays. Considering the stability of the end products, cross-linking by energetic beam irradiation is preferable.
A desirable degree of cross-linking is such that, for example, the xylene extract measured according to ASTM D-2765 is 70 wt. % or less (i.e., a gel content of 30 wt. % or more), and preferably 40 wt. % or less (i.e., a gel content of 60 wt. % or more).
Ethylene can be mentioned as an example olefin.
Specific examples of cross-linked polyolefins include cross-linked low density polyethylenes in which an α-olefin has been copolymerized, and the cross-linked polyolefins disclosed in JP 2002-515530 A.
Due to their cross-linked structure, cross-linked polyolefin-based elastic fibers have excellent stretchability, chemical resistance, weatherability, and heat resistance.
In the present invention, an “inelastic fiber” indicates a fiber without so-called rubber elasticity, such as polyesters, polyamides, polyethylenes, polypropylenes, and other known fibers which do not recover from elongation. Examples thereof include fibers wherein, when 50% elongation is applied (i.e., when stretched to 1.5 times), less than 50% of the elongation is recovered.
Usable inelastic fibers are, for example, fibers made of high-molecular-weight polyethylene having a weight average molecular weight of 1×10⁶or more. The polyethylene fiber or filament is preferably a filament with high tenacity and high elasticity, and especially preferable thereof is a high-tenacity multifilament having a tenacity of at least 20 cN/dtex and a resistance of incipient tension of at least 200 cN/dtex, since a glove made of such a multifilament has excellent cut resistance. In addition, high-tenacity and high-elastic polyethylene filaments have low surface friction coefficients and their abrasion resistance is thus excellent. Therefore, when employed as a glove material, lightness together with a comfortable fit can be achieved.
The tenacity and resistance of incipient tension of a polyethylene filament are measured according to the methods described in the Examples.
When materials etc. for the composite elastic yarn of the present invention are suitably selected from the above-specified ranges, the chemical resistance of the resulting yarn is such that the strength retention therein after chlorine treatment is 85% or more, and preferably 90% or more. The conditions for chlorine treatment and the measuring method for strength retention are as shown in the Examples. The durability of a fabric with such strength retention is practically sufficient to endure cleaning under harsh conditions, chlorine sterilization, and the like.
When materials etc. are suitably selected from the above-specified ranges, the composite elastic yarn of the present invention provides weatherability such that yellowing (Δb value) after light irradiation is 5% or less, preferably 3% or less, and more preferably 1% or less. The method of evaluating yellowing is as described in the Examples. Yarns with such a Δb value are not likely to yellow even when used in harsh conditions, such as longtime outdoor exposure.
(II) Glove
Due to its excellent stretchability, the above-described composite elastic yarn of the present invention is suitable as a material for gloves. A use of the present invention is thus the use of the composite elastic yarn of the invention as a glove material.
The glove of the present invention is partially or entirely composed of a woven or knitted fabric comprising the above-described composite elastic yarn of the invention.
The cut-resistant glove of the present invention can be obtained by knitting yarns including the composite elastic yarn of the invention. It may also be manufactured by cutting and sewing a fabric obtained by weaving the composite elastic yarn of the present invention.
The glove of the present invention may contain, in addition to the composite elastic yarn of the invention, synthetic fibers such as polyesters, nylons, and acrylics; natural fibers such as cotton and animal hair; and regenerated fibers such as rayon. The fibers in the fabric may be in the form of filaments or spun yarns.
In order to achieve high resistance to abrasion, about 1- to about 4-dtex polyester multifilaments and similar nylon filaments are preferable. Polypropylene filaments are especially preferable due to their high lightfastness, excellent chemical resistance and low specific gravity.
The proportion of composite elastic yarn is usually at least 30 wt. % of all the yarns used in the glove, preferably at least 50 wt. %, and more preferably at least 70 wt. %. Such a proportion provides sufficient cut resistance as is required in a glove for injury-prone activities involving glass, knives and the like.
The thus-obtained glove is usable as is. If necessary, a urethane-based resin or ethylene-based resin may be applied thereto for the purpose of providing non-slip performance.
(III) Stretchable Fabric with a Watermark-Like Pattern
The stretchable fabric with a watermark-like pattern of the present invention comprises a cross-linked polyolefin-based elastic fiber and an inelastic fiber, on which a watermark-like design is provided by complete or incomplete removal of the inelastic fiber with partial burn-out printing.
The definition of elastic fiber is as given above. The cross-linked polyolefin-based elastic fiber is also as described above.
The definition of inelastic fiber is also as above. The kind of inelastic fiber is not limited as long as it is destroyable by a burn-out printing process which does not destroy cross-linked polyolefin-based elastic fibers. Such an inelastic fiber may be a natural fiber, chemical fiber, or a combination thereof.
Examples of natural fibers include cotton fibers, hemp fibers, kenaf fibers, fermented-soybean fibers, soy protein fibers, wool fibers, silk fibers, cashmere fibers, mohair fibers and the like. Cotton fibers, silk fibers, wool fibers, soy protein fibers and the like are preferably employed for a natural inelastic yarn, as these fibers achieve a fine hand and texture and high moisture absorbency. Cottons fibers, silk fibers and the like are especially preferable.
Examples of chemical fibers include rayon fibers, cuprammonium rayon fibers, acetate fibers, promix fibers, polylactic acid fibers, polyester-based fibers, polyamide-based fibers, polyolefin-based fibers, vinylon-based fibers, acrylic fibers and the like. Polylactic acid fibers, polyester-based fibers, polyamide-based fibers and the like are preferably selected as a chemical inelastic fiber, due to their excellent solubility. Polyester-based fibers and polylactic acid fibers are especially preferable.
Such inelastic fibers can be used singly or as a combination of two or more kinds. In order to obtain a fabric which combines practicality and a beautiful appearance, it is preferable to use an inelastic yarn, wherein a natural fiber which generally has low acid resistance and a chemical fiber which generally has high acid resistance are combined in the form of a co-twisted yarn, filament mixed yarn, composite spun yarn or covered yarn. With such a structure, it is possible to selectively remove natural fibers by the application of sulfuric acid or the like. Not only cross-linked polyethylene elastic fibers but also other chemical fibers are left undestroyed, whereby beautiful watermark-like patterns can be achieved. Particularly suitable combinations are cotton or silk natural fibers with polyester-based or polylactic acid chemical fibers.
Such an inelastic fiber is served to a cross-linked polyolefin-based elastic fiber to weave or knit. The method for combining elastic and inelastic fibers is not limited; examples of usable fabrics include union fabric, union knit, examples of usable yarns include co-twisted yarns, filament mixed yarns, composite spun yarns, covered composite yarns, and the like. A covered yarn wherein a cross-linked polyolefin-based elastic fiber is covered with an inelastic fiber is preferably employed. Because the elastic fiber is almost completely covered with the inelastic fiber in such a covered yarn, a fabric obtained by weaving or knitting this yarn is a high-tenacity fabric with a pleasant hand and texture.
The role of an elastic fiber in a fabric is to provide stretchability, and the proportion of elastic fiber in the fabric is preferably 20 wt. % or less, and more preferably 15 wt. % or less. The lower limit is preferably at least 3 wt. %, and more preferably at least 5 wt. %. When elastic fibers are used in such a range, the resulting product does not have a plastic-like hand and texture, as is particular to elastic yarns. Furthermore, the surface of such a fabric is smooth. Moreover, as the elastic fiber is unlikely to be exposed at the fabric surface, the fabric has no irritatingly glossy appearance. The above-specified range is also advantageous because these fibers are expensive. Use of an elastic fiber within such a range can achieve practically sufficient stretchability in a resulting fabric.
The fabric of the invention contains a cross-linked polyolefin-based elastic fiber, and thus has good stretchability. The elongation of the fabric under constant load in the direction of the extension of the elastic fiber is preferably 10% or more, and the recovery therefrom is preferably 60% or more. It is more preferable that the elongation under constant load be 15% or more and the recovery be 70% or more. Such a range leads to a fabric having practically sufficient stretchability. Moreover, when a fabric with such a range is made into various shapes and affixed to something, a sufficient flexibility is assured. Although no upper limit to elongation under constant load is given, a limit of about 900% is usually preferable in terms of handleability. Methods for measuring elongation under constant load and recovery therefrom are as indicated in the Examples. When the warp yarns and weft yarns are both made of elastic fibers, the term “elongation under constant load” signifies the mean of the elongations under constant load in both directions.
Such stretchability can be attained by suitably selecting the kinds of elastic and inelastic fibers, and the proportions thereof in a fabric within the above-given ranges.
Portions of the fabric of the present invention have a watermark-like design. The watermark-like design is formed by completely or incompletely removing the inelastic fiber by burn-out printing. In other words, the method of the present invention for manufacturing a stretchable fabric with a watermark-like pattern is a method which forms a watermark-like pattern on a fabric comprising a cross-linked polyolefin-based fiber and an inelastic fiber by partially, completely, or incompletely destroying the inelastic fiber.
Opal-finishing can be mentioned as an example of a method for burn-out printing. This method comprises the steps of printing a fabric with a paste containing sulfuric acid; aluminium sulfate; sodium sulfate; one or more alkaline metal hydroxides, carbonates, and/or bicarbonates; and/or sodium hydroxide, and applying heat to the printed fabric to remove inelastic fibers which have inferior chemical resistance.
The stretchable fabric of the present invention can be obtained by applying partial burn-out printing to a fabric comprising a cross-linked polyolefin-based elastic fiber and an inelastic fiber, and completely or incompletely removing the inelastic fiber therein, thereby forming a watermark-like design on the fabric.

EXAMPLES

The following examples illustrate the present invention in further detail, but the scope of the invention is not limited by these examples.
(I) Example of Glove Production Using Composite Elastic Yarn.
<Evaluation of Chlorine Resistance Ability>
The evaluation was conducted using a testing device as disclosed in JP 2000-97933 A for evaluating chlorine resistance of a swimsuit. The device comprises:

- (1) a water tank for immersion of a test sample; a sample-holding means to hold the sample; a buffer tank for measuring the chlorine concentration and pH of the solution contained in the water tank; an adjustment tank for adjusting the chlorine concentration and pH of the solution in the water tank; and a controlling system for adjusting the chlorine concentration and pH of the solution in the water tank to a set value, based on the measured values of chlorine concentration and pH; wherein
- the chlorine concentration and pH of a solution are adjusted to a set value in the adjustment tank by the controlling system, and the solution is then circulated in the water tank; and the device further comprising:
- (2) a water temperature-controlling system for adjusting the solution temperature in the water tank to a set value; and wherein
- (3) the sample-holding means is supported by a sample-moving means, and is movable at a constant speed in relation to the solution in the water tank; and
- (4) the sample-holding means is supported by a swimsuit-moving means whose installation angle to the water flow is variable.

Using this testing device, changes in pH of a chlorine solution due to immersion of a sample therein are suppressed, and conditions in the water tank wherein the sample is immersed are uniformly maintained. Furthermore, the swimsuit sample receives a water stream, which models the situation of swimming. As a result, measurements at conditions similar to real-life dynamic situations can be made, whereby a practical chlorine resistance evaluation is possible.
1) Preparation of Sodium Hypochlorite Solution
50 ml of sodium hypochlorite (antiformin: manufactured by Nacalai Tesque, Inc.) was obtained, and pure water was added thereto to make the whole quantity 5 l.
2) Preparation of Acetic Acid Solution
50 ml of acetic acid (manufactured by Nacalai Tesque, Inc.) was obtained, and pure water was added thereto to make the whole quantity 5 l.
3) Installation of Specimen
Using the composite elastic yarn, a tubular-knitted fabric specimen was obtained, and fixed in an unstretched state with a pin line on a frame made of stainless steel.
4) Test Conditions
The test conditions are as follows.

Effective chlorine concentration: 3.0 ppm
pH: 7.5
Temperature: 30° C.
Fabric rotation speed: 17.6 rad/s
Fabric installation position: 50 cm away from the rotation axis
(Rotating with the above rotation speed at the above installation position, the specimen receives a water stream at a rate of about 1.4 m/s)
Current angle to the fabric: 90°
Operating (rotation) conditions: intermittent operation with 10 seconds of operation and 10 seconds of stoppage
Operating time: 288 hours

The processed sample was fully washed with water and dried at a room temperature.
<Measurement of Strength Retention>
A plain-knitted fabric was manufactured by knitting a composite elastic yarn with a 16-guage tubular knitting machine having a diameter of 3.5 inches. The obtained fabric was processed for 30 minutes with boiling water, and then subjected to a severe test pursuant to test methods for color fastness to bleaching with hypoclorite defined in JIS-L-0856 (2002) (sodium hypochlorite solution A). After drying the specimen, the composite elastic yarns therein were raveled out, and elastic yarns were taken out therefrom and then subjected to an S-S test to measure the breaking tenacity (d2).
For a product evaluation, a product was first raveled out to take out the composite elastic yarns, and the elastic yarns were separated therefrom and subjected to an S-S test (d1). Separately, a similar product was treated with chlorine in the same manner as above, and elastic yarns were isolated after raveling out of the product, an S-S test carried out, and the breaking tenacity measured (d2). Strength retention (%) was calculated using the formula [(d2)/(d1)]×100.
<Evaluation of Lightfastness>
Using a high-energy sunshine fade meter (carbon arc) manufactured by Suga Test Instruments Co., Ltd., light irradiation treatment was applied to a tubular-knitted fabric made of a composite elastic yarn under the following conditions.

- Temperature: 90° C.
- Irradiation time: 90 hours
  Next, using a SPECTROPHOTOMETER CM-3700d manufactured by MINOLTA, the degree of discoloration was evaluated using the Δb value.
Δb=b1−b2
- b1: b value of the fabric prior to light irradiation
- b2: b value of the fabric after light irradiation
  <Evaluation of Quick-Drying Properties>

Glove samples were placed in tap water for 10 minutes, and spin-dried with a domestic washing machine for 5 minutes. Three monitors wore the processed gloves and evaluated their degree of comfort.
<The Method of Measuring Tenacity and Resistance of Incipient Tension>
Tenacity and elastic modulus were measured as follows. Using a Tensilon manufactured by Orientec Co., Ltd., a specimen of 200 mm (length between chucks) was stretched at the rate of 100% elongation/minute. While the specimen was being stretched, the stress thereof was measured at an atmosphere temperature of 20° C. and a relative humidity of 65%, and a strain-stress curve was thereby obtained. The stress at the breaking point was defined as tenacity (cN/dtex). Elastic modulus was calculated from the tangent of the maximum slope, near the origin of the curve. 10 measurements were taken, and the mean value thereof was employed.

Example 1-1

A yarn made of a 70-dtex monofilament manufactured by melt-spinning an α-olefin-copolymerized polyethylene was cross-linked using an electron beam, obtaining a cross-linked polyolefin fiber (herein after referred to as fiber (A)) (product name: DOWXLA, manufactured by Toyobo Co., Ltd.). Two specimens of the obtained fiber (A) were put together, drafted to 1.55 times, and plied and twisted together with a 440-dtex multifilament fiber (herein after referred to as fiber (B)), which is an ultra-high-molecular-weight polyethylene fiber (product name: SK60, manufactured by Toyobo Co., Ltd.) having a tensile strength of 27 cN/dtex and a resistance of incipient tension of 900 cN/dtex, to obtain a composite elastic yarn (herein after referred to as fiber (X)) wherein the number of twists was 200 T/M. A glove was manufactured with a fashioning stitch machine using only the obtained composite elastic yarn.

Example 1-2

Using one specimen of fiber (A) instead of two, a composite elastic yarn (herein after referred to as fiber (Y)) was obtained in otherwise the same manner as in Example 1-1. Using a fashioning stitch machine, yarn (Y) was knitted with a polypropylene fiber-processed yarn having 84 dtex, 36 filaments, and a glove thereby obtained.

Example 1-3

Using a nylon filament yarn having 77 dtex, 24 filaments instead of the polypropylene fiber-processed yarn, a glove was manufactured in otherwise the same manner as in Example 1-2. Wet coating with a urethane resin was applied to the palm side of the obtained glove.

Comparative Example 1-1

Using an 88-dtex polyurethane-urea elastic fiber (product name: ESPA, manufactured by Toyobo Co., Ltd.;) instead of fiber (A), a glove was produced in otherwise the same manner as in Example 1-1. Because of the high density of the elastic yarn, the obtained composite elastic yarn lacked lightness, and furthermore, it was poor in chlorine resistance and lightfastness.

Comparative Example 1-2

Using an aramid fiber in place of fiber (B), a glove was produced in otherwise the same manner as in Example 1-1. The obtained composite elastic yarn easily discolored, and its lightfastness was poor.

The results of the evaluation of the gloves obtained in the above examples are shown in Table 1 below.

Elastic fiber (dtex)	Ethylene-based	Ethylene-based	Ethylene-based	Urethane-based	Ethylene-based
	140	70	70	88	140
Inelastic fiber	Polyethylene	Polyethylene	Polyethylene	Polyethylene	Aramid
(dtex)	440	440	440	440	440
fiber for union	—	Polypropylene	Nylon	—	—
knit(dtex)		84	77
Proportion of	100	85	86	100	100
composite elastic
yarn (%)
Discoloration Δ d	1	1	3	10	15
Strength retention	95	95	95	47	95
(%)
Quick-drying	Excellent	Excellent	Fair	Good	Fair
properties
Overall evaluation	Excellent	Excellent	Good	Poor	Poor

(II) Production Example for Stretchable Fabric with Watermark-Like Pattern
<Elongation under Constant Load and Recovery Therefrom>

A fabric was tested for elongation in the warp and weft directions under constant load and for recovery therefrom, in accordance with the methods described in “Fuai hyoka no hyojunnka to kaiseki [Standardization and analysis of textures]” (edited by The Textile Machinery Society of Japan), chapter IV, “Nuno no rikigakuteki tokusei no sokutei [Measurement of dynamic characteristics of a fabric]”. Specimens having a width of 20 cm and a length of 5 cm were taken from a fabric both in the warp and weft directions and stretched in the lengthwise direction at a constant rate of 4.00×10⁻³m/sec to a maximum load of 100 gf/cm. The elongation at the maximum load was measured. The stretched specimens then underwent a deformation recovering process. The elongation recovery was defined as the ratio of [the difference between the degree of elongation and the degree of deformation at zero stress after the deformation recovery] relative to [the degree of elongation]. In case of a tubular-knitted fabric, the course direction was employed. For a woven fabric, elongation and recovery in the direction in which the elastic yarn was stretched (when stretched both in the warp and weft directions, the mean value of the two) were observed.

Example 2-1

A plane knitted fabric was obtained by knitting, using a plane knitting machine, a 44-dtex cross-linked polyolefin-based elastic yarn (product name: DOWXLA, manufactured by of Toyobo Co., Ltd.) with a composite spun yarn of 60 cotton yarn count comprising a polyester fiber having 56 dtex, 68 filaments and a cotton yarn of 100's, and cut at the center. Using a screen printing machine (product name: ICHINOSE #7000-type, manufactured by Toshin Kogyo Co., Ltd.), a preliminary floral pattern was printed on the obtained fabric, and a sulfate-containing paste was applied to the patterned portion. The fabric was then heat-treated at 105° C. for 2 minutes with a heater, steam-treated at 130° C. for 30 minutes, washed with water, and dried. Due to this operation, cotton fibers which are poorly acid resistant were selectively dissolved and removed, thereby giving a plain knitted fabric featuring a clear floral watermark-like design.
Elongation and elongation recovery of the obtained knitted fabric were 54% and 85%, respectively.

Example 2-2

The procedure of Example 2-1 was followed, except that a vinylon fiber having 44 dtex, filaments was used instead of the polyester fiber. As in Example 2-1, the cotton fiber was dissolved and removed, and a plain-knitted fabric provided with a beautiful floral watermark-like design was obtained. Elongation and elongation recovery of this knitted-fabric were 62% and 81%, respectively.

Comparative Example 2-1

The procedure of Example 2-1 was repeated, except for using a 44-dtex polyurethane elastic yarn (product name: ESPA 465, manufactured by Toyobo Co., Ltd.) instead of the 44-dtex cross-linked polyolefin-based elastic yarn. The polyurethane elastic fiber was dissolved by acid, and only the polyester fiber was left in the fabric. As a result, the fabric contained holes, and no floral watermark-like pattern was formed thereon. The elongation of this fabric was 53%, whereas elongation recovery was low, at 42%.
The composite elastic yarn of the present invention exhibits excellent chemical resistance and high lightfastness, and is thus suitable for application to swimsuits, underwear, outerwear, diaper covers, sanitary products, tents and like outdoor products, industrial materials and the like.
When using high-tenacity fibers as inelastic fibers, the obtained yarns are suitable as a material for gloves for use in dangerous work such as handling iron plates with sharp edges or burrs, dealing with glass, and in dangerous work using knives, such as the processing of meat and cutting of large fish.
Moreover, as the stretchable fabric of the present invention features a beautiful appearance with a watermark-like pattern in addition to the excellent stretchability, it is suitable as a material for underwear and sportswear.

Comp. Ex. 1-1

Comp. Ex. 1-2

1. A composite elastic yarn comprising a polyolefin-based elastic fiber and a polyolefin-based inelastic fiber.

2. A composite elastic yarn according to claim 1, wherein the polyolefin-based elastic fiber is a cross-linked polyolefin-based elastic fiber.

3. A composite elastic yarn according to claim 1, wherein the polyolefin-based inelastic fiber is a high-molecular-weight polyethylene fiber having a weight average molecular weight of at least 10×10⁵.

4. A composite elastic yarn according to claim 3, wherein the high-molecular-weight polyethylene fiber is a high tenacity multifilament fiber with a tenacity of 20 cN/dtex or more and a resistance of incipient tension of 200 cN/dtex or more.

5. A composite elastic yarn according to claim 1, comprising 1 to 50 wt. % of the polyolefin-based elastic fiber.

6. A composite elastic yarn according to claim 1, which is a covered yarn formed by covering the polyolefin-based elastic fiber with the polyolefin-based inelastic fiber.

7. A glove partially or wholly composed of a woven fabric or knitted fabric comprising the composite elastic yarn of claim 1.

8. A glove according to claim 7, wherein a portion comprising the composite elastic yarn of claim 1 contains at least 30 wt. % of the composite elastic yarn.

9. A method for manufacturing a glove, comprising weaving or knitting the composite elastic yarn of claim 1.

10. (canceled)

11. A stretchable fabric with a watermark-like pattern, the stretchable fabric comprising a cross-linked polyolefin-based elastic fiber and an inelastic fiber, and having a watermark-like pattern produced by complete or incomplete removal of the inelastic fiber with partial burn-out printing.

12. A stretchable fabric according to claim 11, wherein the inelastic fiber is at least one kind of natural fiber selected from the group consisting of cotton fibers, hemp fibers, kenaf fibers, fermented soybean fibers, soy protein fibers, wool fibers, silk fibers, cashmere fibers, and mohair fibers.

13. A stretchable fabric according to claim 11, wherein the inelastic fiber is at least one kind of chemical fiber selected from the group consisting of rayon fibers, cuprammonium rayon fibers, acetate fibers, promix fibers, polylactic acid fibers, polyester-based fibers, polyamide-based fibers, polyolefin-based fibers, and acrylic fibers.

14. A stretchable fabric according to claim 11, wherein the inelastic fiber comprises at least one kind of natural fiber selected from the group consisting of cotton fibers, hemp fibers, kenaf fibers, fermented soybean fibers, soy protein fibers, wool fibers, silk fibers, cashmere fibers, and mohair fibers; and at least one kind of chemical fiber selected from the group consisting of rayon fibers, cuprammonium rayon fibers, acetate fibers, promix fibers, polylactic acid fibers, polyester-based fibers, polyamide-based fibers, polyolefin-based fibers, and acrylic fibers.

15. A stretchable fabric according to claim 11, wherein the burn-out printing is opal finishing.

16. A stretchable fabric according to claim 11, comprising 3 to 20 wt. % of the cross-linked polyolefin-based elastic fiber.

17. A method for manufacturing a stretchable fabric with a watermark-like pattern, comprising applying partial burn-out printing to a fabric comprising a cross-linked polyolefin-based elastic fiber and an inelastic fiber, thereby completely or partially removing the inelastic fiber of a processed portion of the fabric to make a watermark-like pattern.