JPS5921970B2 - Polyester fiberglass - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to a method for doubling undrawn polyester filament yarns having different birefringence indexes and subjecting the yarns to simultaneous stretching and false twisting.

[Prior art]

Generally, as the birefringence of synthetic fiber filament yarns increases, the elongation modulus also increases.If synthetic fiber filament yarns with different birefringence indexes (in other words, different elongation moduli) are aligned and subjected to simultaneous stretching and false twisting, By winding the filament yarn with a small elongation modulus or a filament yarn with a large elongation modulus, a special core-sheath two-layer structure crimped yarn (hereinafter sometimes simply referred to as "crimped yarn") can be obtained.

In this case, especially woven or knitted fabrics made of crimped yarns made of polyester filament yarns exhibit a spun-like feel due to the characteristics of polyester fibers and their special crimped structure.

By the way, the formation of the above-mentioned two-layer structure is a phenomenon that occurs because the filament having a small birefringence index is deformed or thicker than the filament having a high birefringence index.

In other words, a yarn length difference occurs between the two yarns, and a wound structure is obtained due to the slack due to this yarn length difference and the false twisting torque.

Therefore, the entanglement of the single yarns constituting this two-layered crimped yarn is alternately twisted, and when pulled or tightened, the entanglement is easily broken and separated, as shown in FIG. 2, which is a drawback.

Here, 1 indicates a yarn with a large birefringence index, and 2 indicates a yarn with a small birefringence index.

When the yarn foot difference between the yarns, that is, the slack, increases to 8% or more, this tendency becomes remarkable, and no entanglement occurs at all, making false twisting extremely difficult.

However, a yarn length difference of 8 or more is an essential requirement for imparting a bulky feel to a two-layered crimped yarn, and a yarn length difference of less than this will reduce its value as a product by half.

Here, a load of 0.1 g per denier was applied to the crimped yarn obtained by folding and crimping the double yarn, and markings were made on both ends of a length of about 1 m, and then the birefringence was Separate the crimped yarns corresponding to different raw yarns, apply a load of o and H per denier to each separated yarn, measure the length between the marks marked earlier, and find the longest yarn. 7. It is a value obtained by (11-12) x 12 x 100 (%) when the thread of the short thread is 12.

When the yarn foot difference is 8% or more and the crimped yarn is forced by a guide or the like during the knitting machine process, yarn pools occur, which is not only difficult to handle, but also deteriorates the quality of the finished woven or knitted product. .

[Purpose of the invention]

The purpose of the present invention is to enable stable processing in the simultaneous stretching and false twisting process that creates a yarn length difference of 8% or more, which is necessary to obtain a wound yarn with a bulky feel, and to make it resistant to ironing. Another objective is to provide a crimped yarn with a stable structure.

[Structure of the invention]

According to the present invention, two or more types of polyester filament undrawn yarns having birefringence indexes different by 0.02 or more are combined and simultaneously stretched and false-twisted to produce a core-sheath two-layer structure yarn with a yarn length difference of 8% or more. Provided is a method for producing a polyester crimped yarn, which comprises the steps of:

Furthermore, regarding this, the inventors of the present invention have conducted various studies on how to prevent the entanglement and destruction of crimped yarns that cause yarn length differences, and the generation of yarn pools. Regardless of the twisting processing conditions, in order to avoid the above-mentioned problem at all, immediately after the yarn leaves the false twisting tool, an air jet nozzle is passed through the yarn to help entangle the yarn. We have discovered that it is optimal to generate

The raw yarn used in the present invention is not particularly limited as long as it is a combination of undrawn polyester filament yarns with a birefringence difference of 0.02 or more, but the polyester filament yarn with a high birefringence index is made of thick single fiber denier fibers. The combination of polyester filament yarn with a low birefringence index and thin single fiber denier fibers creates a two-layer structure yarn in which a thick single fiber denier yarn serves as a core and thin single fiber denier yarns are wound around it. Woven and knitted fabrics made from crimped yarns are preferable because they have an excellent texture of being soft and firm.

Such a difference in birefringence can be imparted by changing the spinning speed between the yarns used or by changing the stretching ratio.

Also, if you use a polyester filament yarn with high birefringence that has high strength and high (intrinsic) viscosity, and use a polyester filament yarn with low birefringence that has low strength and low (intrinsic) viscosity, Since the yarn has a two-layer structure in which a strong filament yarn serves as a core and less strong filament yarns are wound around it, woven or knitted fabrics made from this crimped yarn exhibit excellent pill resistance and durability. Therefore, it is preferable.

Next, the above-mentioned raw yarn is subjected to simultaneous stretching and false twisting in a stretched or doubled state.

In this case, the stretching ratio may be appropriately set depending on the birefringence index of the yarn, but it is usually in the range of 1.2 to 2.5.

On the other hand, although there are no particular restrictions on the false twisting tool, a common spindle type false twisting machine is generally used.

In the present invention, what is important is that the yarn is introduced into the air injection nozzle immediately after leaving the false twister.

Here, "immediately after leaving the false twisting device" means that the yarn leaving the false twisting device is not rubbed by guides, etc., and the air injection nozzle is generally used for taslan processing. A nozzle, an interlacing nozzle, or an air swirl nozzle which imparts a counter-rotation of the yarn to the false twisting spindle is used.

[Action/effect of the invention]

In this way, by passing the yarn through an air injection nozzle following simultaneous stretching and false twisting, the yarn does not separate even under conditions where the yarn length difference is greater than 8%, resulting in extremely stable yarns as shown in Figure 1. A double layered yarn is obtained.

The difference in yarn length after crimping is mainly related to the difference in birefringence of the yarns to be twisted, and this difference is large in Japanese dogs, but it is possible to increase the number of false twists or increase the processing tension. But it gets bigger.

Furthermore, the processing temperature, the denier of the yarn to be doubled, the number of filaments, etc. also have an effect.

There are many factors that affect the yarn length difference as described above, but in order to at least make the birefringence difference of the yarns to be doubled 0.02 or more, and to use the processing tension to increase the yarn length difference, we decided to use a simultaneous processing method. By employing the stretch false twist processing method, the yarn foot difference can easily be larger than 8%, and depending on the birefringence difference and crimping processing conditions, it can be increased to 25 to 35%.

Furthermore, regarding this point, in order to obtain a double-layered yarn by utilizing the difference in birefringence between yarns, it is necessary to apply as high a tensile stress as possible to the yarn, and this requires The simultaneous stretching and false twisting method, which has a high

If this drawn false twisting method is adopted, undrawn yarns with different birefringence indexes will inevitably be used.

When processed in this way, when heated, the filament yarn with a higher birefringence index is less deformed (harder to stretch) than the filament yarn with a lower birefringence index, so the tension becomes higher, and therefore the filament yarn with a higher birefringence index becomes higher in tension when heated. It becomes easier to enter the core.

On the other hand, filament yarns with a low birefringence index are more easily stretched and exposed to the outer layer, and are wound around the filament yarn in the core.

When this is then untwisted, the filament yarns in the outer layer (because the yarn length difference is larger than the filament yarn in the core) become slack and stretch out, giving a bulky feel to the entire system.

By the method of the present invention, it is possible to false-twist yarns with a double refractive index difference of 0.02 or more, which was conventionally extremely difficult or impossible to do by heating processing, that is, a false twisting process that produces a large yarn length difference of 8% or more. Twisting can be performed without any trouble, and a two-layer crimped yarn with a stable structure and good handling properties can be easily obtained.

Woven and knitted fabrics using this crimped yarn have a spun-like texture that is bulkier than those using conventional crimped yarns. Furthermore, there is also diversity in that the eye surface, texture, etc. can be changed.

Further, the woven or knitted fabric made of the crimped yarn obtained by the method of the present invention exhibits excellent napping processability, and the napping fabric also has good anti-pilling properties.

As described above, the scope of application of the present invention is wide and the effects are remarkable.

The present invention will be explained below with reference to Examples.

〔Example〕

Example 1 Birefringence obtained by high-speed spinning is 0.06, intrinsic viscosity η is 0.65, total fineness is 113 denier, number of filaments is 24 polyester undrawn filament and birefringence is 0.
．． 04. Undrawn polyester filament yarns with an intrinsic viscosity η of 0.65, a total fineness of 113 denier, and 36 filaments are aligned and spun together, then stretched using a spindle-type stretching false twisting machine with a heater length of 1 m. Magnification 1.5, spindle rotation speed 40 x 10' rpm, number of false twists 2500
T/M (Z direction false twisting), stretching false twisting was performed at a heater temperature of 200°C.

The yarn exiting the false twisting spindle was immediately introduced into an interlace nozzle to intertwine the yarns, passed through a delivery roller, and was wound onto a bobbin by a friction roller.

The obtained crimped yarn has a fineness of 150 denier and has a yarn foot difference of 20%, with the filament yarn having a large single fiber denier, that is, having a small number of filaments, serving as the core, and the filament yarn having a small single fiber denier, that is, the filament yarn having a small number of filaments forming the core. The yarn had a two-layer structure in which a large number of filament yarns were wound around the filament yarn almost continuously and intertwined.

This crimped yarn does not cause yarn separation during the false twisting process or the weaving and knitting process during its production, and is extremely easy to handle, and the woven and knitted fabrics made with this yarn have a firm and soft feel. It exhibited a spun-like texture that cannot be obtained with conventional false-twisted yarns.

The state of this crimped yarn is shown in FIG.

In the figure, 1 is a polyester undrawn filament yarn with a high birefringence index, and 2 is a polyester undrawn filament yarn with a low birefringence index.

For comparison, the false twisting process was performed without using an air jet in the above example, but in this case, yarn separation occurred during processing, resulting in yarn pooling in the guide section and yarn wrapping around the delivery roller. Therefore, false twisting was extremely difficult.

In addition, when the resulting crimped yarn was knitted and woven,
The yarn separation and nep-like yarn pools occurred, making it difficult to handle in the knitting and weaving process, and the product quality and texture of the knitted fabric were poor.

The state of this crimped yarn is shown in FIG.

Example 2 A polyester undrawn filament yarn with a birefringence of 0.06, an intrinsic viscosity η of 0.65, a total fineness of 113 denier, and 24 filaments obtained by high-speed spinning and a birefringence of 0.03 and an intrinsic Undrawn polyester yarns with a viscosity of 0.45, a total fineness of 113 denier, and 36 filaments were pulled together and combined, and then stretched and false-twisted using the same stretch-false twisting machine as in Example 1 under the same conditions. .

Here, the yarns coming out of the false twisting spindle were passed through an air swirling nozzle that swirled them in the S direction, thereby imparting entanglement between the yarns.

The obtained crimped yarn has a fineness of 150 denier and a yarn length difference of 25%, and has a two-layer structure in which a filament yarn with a high intrinsic viscosity forms the core, and a filament yarn with a low intrinsic viscosity is wound around the core. It was a thread.

This structural yarn does not cause yarn separation during the false twisting process or the weaving and knitting process in its production, and is easy to handle. Furthermore, woven and knitted fabrics made from this crimped yarn have excellent anti-pilling properties. It had a span-like texture.

[Brief explanation of the drawing]

FIG. 1 is an enlarged side view showing the structure of a crimped yarn obtained by the method of the present invention, and FIG. 2 is an enlarged side view of a crimped yarn that has been merely false-twisted for comparison. In the figure, 1 indicates a thread with a high birefringence index, and 2 indicates a thread with a small birefringence index.

Claims (1)

[Claims] 1 Two or more undrawn polyester filament yarns with birefringences different by 0.02 or more are combined and simultaneously stretched and false-twisted to produce a core-sheath two-layer structure yarn with a yarn foot difference of 8% or more, followed by air injection. A method for producing crimped polyester yarn, characterized by passing the yarn through a nozzle to cause entanglement between the yarns.