JPS61201037A - Double covering coated elastic yarn - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is directed to a double-covered coated elastic yarn made by doubly wrapping a thermoplastic synthetic fiber yarn such as polyamide around an elastic yarn such as polyurethane. Regarding improvements.

In particular, the present invention relates to a coated elastic yarn useful as a material for socks, stockings, and the like.

[Prior art]

Elastic yarns such as polyurethane yarns have excellent elastic properties, but on the other hand, they have drawbacks such as dyeing properties9 mechanical strength and abrasion resistance properties, so thermoplastic synthetic fibers such as polyamide filaments are double wound. It is widely used as a coated elastic yarn with double covering. For example, JP-A-47-19
Japanese Patent No. 146 describes that a covering thread is wound around a polyurethane elastic thread while it is stretched to cover the thread. In such an example, the number of twists of the bobbin thread of the double cover is 2600.
It is common to improve the coverage by combining the denier of the covering yarn and the corresponding number of first twists and second twists, as shown in the figure. However, such a method causes problems such as increased manufacturing cost and decreased elasticity due to the high number of twists. Covering properties can also be improved by increasing the denier of the covering yarn, but the double covering yarn itself becomes thicker, which is a limitation in applications where transparency of the resulting product is strongly required, such as when used for stockings. It is something that

Furthermore, Japanese Patent Publication No. 45-18065 describes a method of covering a polyurethane elastic yarn with a false-twisted stretchable yarn, but the yarn obtained by this method has the elasticity of the false-twisted stretchable yarn that is the covering yarn. , making full use of its original characteristics such as bulkiness. This covered yarn has an appearance similar to that of a stretch-treated yarn and has a soft appearance, and is an improvement on a so-called single covered yarn. Therefore, such cutling yarns are still undesirable in fields such as stockings, where transparency of the resulting product is strongly required.

[Problem that the invention seeks to solve]

The main object of the present invention is to solve the above-mentioned problems and provide a double-covered covered elastic yarn with good coverage, compact yarn form, and good productivity. It is.

Furthermore, even in a state with excellent covering properties, the torque of the covered elastic yarn is reduced, making it easy to knit in two.

It is an object of the present invention to provide a double-covered covered elastic yarn capable of obtaining a knitted fabric with a beautiful knitted part.

[Failure to solve the problem]

In order to achieve the above object, the present invention consists of the following configuration.

In other words, in a covered elastic yarn formed by doubly wrapping a covering yarn made of long fibers of a thermoplastic polymer around a core yarn made of two elastic yarns, the covering yarn wound inside is It consists of a crimped multifilament yarn having a cross-sectional shape factor of 1.2 to 1.6 as an average value of the constituent single fibers, and is characterized in that the covering yarn wound on the outside is a non-crimped yarn. It is a coated elastic yarn with double covering.

More preferably, the covering yarn wound on the outside has an average value of 1.2 to 1.6 as the average value of each constituent single fiber in the same cross section.
It is made of non-crimped multifilament yarn having a cross-sectional shape factor of .

Note that the cross-sectional shape factor is K w L/Lc
Here, L means the outer circumferential length of the cross section of the fiber, and Lc means the outer circumferential length of a circle having the same cross-sectional area as the fiber.

[Effect]

The present invention will be explained in more detail below.

The type of covering yarn, its characteristics, and the cross-sectional shape of the single yarn are important in order to reduce the number of twists when wrapping the covering yarn, improve coverage, and further reduce the torque of the yarn. In view of this point, the inventors of the present invention made extensive studies and found that the objects of the present invention can be achieved by using a crimped yarn with a deformed cross section as the covering yarn. That is, first, a crimped multifilament yarn having a cross-sectional shape factor of 1.2 to 1.6 as the average value of each component single fiber in the same cross section is used as the covering yarn to be wound inside. The crimped yarn wrapped inside becomes 2 due to the bending of the fibers.
This originally improves the coverage, but by making the cross-sectional shape of the fibers non-circular, the coverage is significantly improved. Even if fibers with a circular cross section are false-twisted, the fibers will become non-circular due to the heating action, but in order to obtain an even greater effect, it is necessary to change the cross-section of the fibers used in the false-twisting process. It is preferable to make the shape non-circular so that the cross-sectional shape factor K of the obtained crimped yarn is 1.2 to 1.6 as the average value of each constituent single fiber in the same cross section.

Although the crimped yarn wound on the inside exhibits a covering effect, it is not preferable in terms of the high tension of the covered elastic yarn. This restricts the bulk of the thread in the diameter direction.

In this way, by tightening the internal bulk from the outside, not only does the external coverage improve, but the stability against external forces such as ironing is improved, resulting in substantial coverage and thread form. Improves compactness. As a result, it is possible to reduce the number of twists in one winding, and productivity is also improved.

When stockings are made using such a double-covered covered elastic yarn, a clean product with good transparency can be obtained, and its durability when actually worn is greatly improved.

If the cross-sectional shape factor K of the crimped yarn is smaller than 1.2, a sufficient covering effect cannot be obtained. On the other hand, the cross-sectional shape coefficient K is 1
．． If it exceeds 6, the abrasion resistance of the resulting coated elastic yarn will be lowered, and the color fastness and texture will also be lowered, making it unsuitable for practical use. Namely.

In general, non-circular cross-section fibers are compared to round-section fibers.

Although the mechanical strength is reduced, the covered elastic yarn obtained by using the above-mentioned non-circular cross-sectional fiber having the specific cross-sectional shape as the covering yarn has virtually no problem. The cross-sectional shapes of these non-circular cross-sectional fibers are 7-shaped and T-shaped.

It may have any shape such as an X-shape, but it is further deformed by the crimp process. For example, if you use a figure 7 shape to perform false twisting.

It has a flat cross-sectional shape with bent legs, satisfies the cross-sectional shape factor, and improves the coverage of the covered elastic yarn.

An example of a fiber cross-sectional shape obtained by false twisting the Y-shaped cross-section fiber yarn shown in FIG. 1 is shown as a model.

The processing method for obtaining the crimped yarn to be wound on the inside may be any method such as false twisting or pressing, but it is preferable to use false twisting to provide good coverage. In terms of torque balance, stretchability, etc., this false twisted yarn is preferably one obtained by heating, heat setting, and untwisting in the opposite direction to the twisting direction of the inner winding.

Next, the covering yarn wound on the outside suppresses the bulk of the crimped yarn wound on the inside and creates a uniform yarn surface shape.
Must be non-crimped yarn. Although this non-crimped yarn can achieve the desired effect even if it is a yarn with a circular cross-section, in order to improve the properties such as holding down the covering yarn wound inside, stability, and abrasion resistance, the above-mentioned It is preferable to have a cross section with a cross-sectional shape factor K of 1.2 to 1.6. Also.

When considering the torque of the covered elastic yarn, it is preferable to use a torque type non-crimped yarn that offsets the torque generated by winding the crimped yarn inside.

The elastic fibers used in the present invention are preferably polyurethane elastic fibers commonly referred to as spandex fibers, but other types of elastic fibers may be used.

On the other hand, polyamide, polyester, polyolefin, polyacrylic fiber, etc. are used as the long fibers of the thermoplastic polymer constituting the coating thread, but dyeing properties 9 mechanical strength,
Polyamides with excellent friction resistance are preferred, and among polyamides, nylon 6 is particularly preferred.
or nylon 66 fibers are preferred.

〔Effect of the invention〕

According to the above-mentioned aspect 9 of the present invention, a covered elastic yarn is provided which simultaneously satisfies many of the conventional problems such as coverability, stretchability, and manufacturing cost. The present invention effectively utilizes the effect of significantly improving coverage by covering with a crimped yarn with a non-circular cross section and a non-crimped yarn with a non-circular cross section. This is something that could not be realized due to a problem and has been improved to make it practical.

EXAMPLES The present invention will be explained in further detail with reference to Examples below.

〔Example〕

20 denier, 3 filament spandex fiber yarn was stretched 52 times and double covered using a normal covering machine (first twist 2800v in 2 directions).

Ply twisting was performed in the S direction 2300 times/rn). The covering thread used in this case and its covering conditions are as shown in Table 1, and the covering thread has 15D-5F on the inside.

A crimped yarn made by false twisting a yarn made of nylon 6 with a round cross section and a trilobal cross section is used in combination with a yarn made of nylon 6 with a round cross section and a trilobal cross section of 15D-5F on the outside. Yarn type, cross-sectional shape factor K.

was performed with various changes.

The coverage of the obtained coated elastic yarn was visually evaluated using a magnifying glass, and evaluated in four stages: ◎→○→Δ→×.

◎ and ○ are practical, but Δ and × are problematic and impair the quality of the stockings. The stretchability of the covered elastic yarn is defined as the elongation rate of the covered elastic yarn until the loosened portion of the covered yarn is completely stretched after the covered elastic yarn is treated with boiling water.

As can be seen from the above results, it can be used as a coating thread.

Coverability is achieved by covering the inside with a crimped yarn with a non-circular cross section and further covering the outside with a non-crimped yarn.

A coated elastic yarn with a good stretch rate can be obtained. More preferably, the non-crimped yarn covering the outside also has a non-circular cross section, which is effective for improving the covering property. If the degree of non-circularity becomes too large, the texture becomes rough and hard, resulting in a textured texture, which is not preferable.

[Brief explanation of drawings]

FIG. 1 shows an example of the non-circular cross-sectional shape of the covering yarn of the present invention, and is a model showing an example of the fiber cross-sectional shape obtained by false twisting a Y-shaped cross-section fiber yarn. .

Claims (2)

[Claims] (1) In a covered elastic yarn formed by doubly wrapping a covering yarn made of long fibers of a thermoplastic polymer around a core yarn made of an elastic yarn, the covering yarn wound on the inside has the same cross section. Consisting of crimped multifilament yarn having a cross-sectional shape factor of 1.2 to 1.6 as an average value of each constituent single fiber,
A double-covered covered elastic yarn characterized in that the covering yarn wound on the outside is made of a non-crimped yarn. The cross-sectional shape factor K is the value of K=L/Lc, where L means the outer circumference of the fiber cross section, and Lc means the outer circumference of a circle having the same cross-sectional area as the fiber. It is something to do. (2) The covering yarn wound on the outside is characterized by being made of non-crimped multifilament yarn having a cross-sectional shape factor of 1.2 to 1.6 as an average value of each component single fiber in the same cross section. A double-covered covered elastic yarn according to claim (1).