JPH0217655B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a spun yarn-like polyester processed yarn that can give the yarn the appearance and feel of a woven or knitted yarn. Conventionally, in order to impart spun yarn-like appearance and texture to polyester yarn, there have been methods to impart bulkiness and fluff to crimped yarn by subjecting crimped yarn to fluid agitation treatment, or by rubbing crimped yarn. Various processing methods have been proposed, including a method of generating fluff by adding bulkiness and fluff. However, all of these processing methods require multiple steps such as crimping and fluffing, which not only increases the processing cost, but also increases the processing cost by using fluid agitation treatment to add fluff to the resulting processed yarn. Because it has teardrop-like coarse loop fuzz, when it is made into fabric, it has the disadvantage of inducing the so-called fastener phenomenon in which the fabrics get caught on each other.Furthermore, in the method of imparting fuzz by rubbing, the processed yarn has cut fuzz. Therefore, it had the disadvantage of poor pilling performance. The present inventors have developed a method for producing a spun yarn-like polyester false twisted yarn that does not have such drawbacks and can give the appearance and texture of a woven or knitted yarn, and has developed a method for producing a polyester false-twisted yarn that is highly oriented and undergoes a relaxation heat treatment at a high temperature. After that, a patent application was filed in 1982 for a method of heating, stretching, and false twisting.
- Proposed in issue No. 199169. The yarn obtained by the above invention has a spun yarn-like appearance, with the outer layer having crimped crimp and arch-shaped loop fuzz, and the inner layer having a core made of fused filament. It has the advantage of giving firmness, waist, etc. However, because excessive loops are mixed in the arch-shaped loop fuzz in the outer layer, the loop fuzz gets entangled with each other on the winding material such as cheese, reducing the unwinding property during knitting machines and reducing the openness during weaving. There was also a problem that the strength was low, so that fuzzing was likely to occur. The present inventors conducted extensive studies in view of the above points, and as a result, by lowering the relaxation heat treatment temperature and increasing the stretching ratio during false twisting than in the above invention,
The present invention was developed based on the knowledge that it is possible to make the arch-shaped loop fuzz in the outer layer finer and to make the threads uniform and bundled. The inner layer has a core made of fused filament, and has a spun yarn-like appearance.
Not only does it provide texture, but it also provides unwinding properties during weaving and weaving.
An object of the present invention is to provide a method for producing a spun yarn-like polyester processed yarn with improved openability and strength. That is, in the present invention, highly oriented polyester undrawn yarn with a birefringence △n of 15 to 80 × 10 ^-3 and a crystallinity of 20% or less obtained by high-speed spinning is subjected to a heating device in a relaxed state of 30% or more. A method for producing a spun yarn-like polyester processed yarn, which is characterized by heat-treating at a temperature of 180°C or lower without contact, and then drawing and false twisting the yarn at a draw ratio A that satisfies the following formula (1). It is. A>1.1 (1+a/100)...(1) However, a: Relaxation rate (%) The present invention will be described in detail below. The supplied yarn used in the method of the present invention is an undrawn polyester yarn having a birefringence Δn of 15 to 80×10 ⁻³ and a crystallinity of 20% or less. In the method of the present invention, as will be described later, the yarn is first subjected to relaxation heat treatment to sufficiently shrink the yarn, while crystallization proceeds without significantly changing the degree of orientation in the fiber axis direction, thereby reducing the residual elongation. increase.
Furthermore, since it can be sufficiently shrunk by relaxing heat treatment, it is not a drawn yarn but an undrawn yarn, and there is less problem of thermal embrittlement in heat treatment processing including drawn false twisting, so high speed spinning (e.g. spinning speed) is possible. 2500～
5500m/min) and the birefringence △n obtained is 15~
It is necessary to use a highly oriented undrawn polyester yarn having a yarn quality characteristic value of 80×10 ^-3 and crystallinity of 20% or less. Here, if the birefringence △n of this highly oriented polyester undrawn yarn is less than 15 × 10 ^-3 , yarn breakage will occur frequently due to embrittlement of the yarn during the drawing false twisting process that follows the relaxation heat treatment, and the drawing false twisting will occur. Processing becomes difficult. Moreover, if it exceeds 80×10 ⁻³ , it is not preferable because it becomes difficult to run the yarn while sufficiently contracting it in a relaxed state. In addition, the degree of crystallinity must be 20% or less; if it exceeds 20%, the improvement in the degree of orientation during stretching and false twisting will be small, and if anything, the disorder of orientation due to heat shrinkage will cause fiber embrittlement. This is not desirable because it becomes Next, the present invention heat-treats the highly oriented undrawn polyester yarn at a relaxation rate of 30% or more and at a temperature of 180°C or less without contacting with a heating device, so that the single filaments constituting the yarn are randomly distributed in the longitudinal direction. By shrinking, some of the single filaments in the cross section of the yarn have a large fineness, and a yarn having a yarn length difference between the single filaments is formed. Here, the relaxation rate refers to the ratio of the difference between the supply speed and the take-up speed to the take-up speed, expressed as a percentage. The relaxation rate during the above-mentioned relaxation heat treatment must be 30% or more, preferably 50% or more, and the relaxation rate must be such that sufficient shrinkage can be achieved. If the relaxation rate is less than 30%, it is not preferable because it becomes difficult to provide the yarn with a two-layer structure consisting of a crimped crimp and a core portion fused together with arched loop fluff by the draw false twisting process described later. The relaxation heat treatment must be carried out without bringing the yarn into contact with a heating device so that the single filaments constituting the yarn can be sufficiently shrunk in free positions. If the above-mentioned treatment is performed by bringing the yarn into contact with a heating device, tension is applied due to the contact resistance of the yarn, which inhibits contraction at a free position, which is not preferable. The temperature during relaxation heat treatment is
It is necessary to keep the temperature within a temperature range that allows the yarn to shrink by 30% or more at 180°C or lower, preferably 160 to 140°C. By heat-treating at 180°C or lower in this way, the crimped crimps and arched fuzz that make up the outer layer of the processed yarn obtained by the drawing and false twisting process described later become finer, and the yarn becomes more even and bundled. At the same time, the strength is improved. If the temperature during the above-mentioned relaxation heat treatment exceeds 180°C, the resulting processed yarn will have a clear two-layer structure, but the arch-like fuzz will be mixed with excessive fluff, resulting in decreased unwinding properties and further thermal embrittlement. As a result, the strength also decreases, which is not preferable. In the present invention, the yarn obtained by the above-mentioned relaxation heat treatment is simultaneously stretched and false-twisted at a specific stretching ratio A, and a difference in the amount of torsional deformation is generated during stretching and false-twisting between the outer layer and the inner layer of the yarn. A core made of filament with an inner layer fused is formed, and a spun yarn-like polyester yarn having a two-layer structure is obtained in which the core is covered with fine and uniform crimp crimp and arched loop fuzz. In this case, the stretching ratio A during stretch false twisting is selected to be within the range that satisfies A>1.1 (1+a/100) and does not cause cut fuzz, assuming that the relaxation ratio during relaxation heat treatment is a%. There is a need. If the stretching ratio is smaller than the above, although the film has a two-layer structure, the uniformity of the arched loop fluff will be insufficient and the strength will also be low, which is not preferable. In addition, the temperature during the above-mentioned stretch false-twisting is not particularly limited, and processing can be performed at a normal false-twisting temperature, but if the false-twisting temperature is too high, the proportion of the inner layer that is fused and bonded increases, resulting in two layers. Textile-like appearance due to structure,
The texture decreases, while if the false twisting temperature is too low, the degree of convergence of the yarn decreases. Therefore, the crimped crimp and arched loop fuzz forming the outer layer of the processed yarn and the fusion bonded portion of the filament forming the inner layer are appropriately bundled to improve unwinding properties, opening properties, etc. during weaving and weaving. For this purpose, the false twisting temperature is preferably 210 to 230°C. Furthermore, the number of false twists during drawing and false twisting is determined by setting the yarn fineness after drawing to D (denier),
If the appropriate number of false twists is T (twices/m), T = 18000/√~28000/√, which is slightly less than the normal number of false twists.The two-layer structure of the processed yarn is clearly defined, and the unwinding property is improved. This is desirable from the point of view of improving. FIG. 1 is a schematic process diagram showing an example of the manufacturing process of the method of the present invention. The highly oriented undrawn yarn F obtained by high-speed spinning is pulled out from the spool 1, passes through the tensor 2, passes through the feed roller 3, and is 30%
The material is supplied in the above-mentioned relaxed state, and is taken up by the first delivery roller 5 while being contracted in a non-contact state within the relaxation heater 4 whose temperature is 180° C. or less. The yarn is subsequently fed into the stretch false twisting zone, where it is stretched at a predetermined stretching ratio between the first delivery roller 5 and the second delivery roller 8, and simultaneously false twisted by the false twisting spindle 7. Heater 6
is heat-set. The yarn thus processed is wound into a package 10 by a winding roller 9 into a spun yarn-like bulky processed yarn. Here, a reheating heater 11 is provided to heat-treat the yarn coming out of the second delivery roller 8 in a relaxed or tensioned state to change the bulkiness, reduce torque, and thermal stability, and then deliver the yarn to the third delivery roller 8. The package may be rolled up onto the package 10 by the winding roller 9 via the low roller 12. The processed yarn obtained by the method of the present invention has a two-layer structure, as shown in Fig. 2, in which the outer layer has fine, evenly distributed crimp and arch-like loop fuzz, and the inner layer has a core made of fused filament. It has a spun yarn-like appearance, and the firmness and stiffness provided by the fused core gives it a texture similar to wool spun yarn, making it a spun yarn that closely resembles spun yarn in both appearance and texture. Thread-like threads are obtained. In addition, in the yarn obtained by the present invention, the crimped crimp and arched loop fuzz forming the outer layer are finely and evenly distributed.
In addition, the core of the filament fused to the outer layer is appropriately bundled, improving the unwinding property during knitting and the opening property during weaving, and further improving the strength during knitting and weaving. It is possible to prevent the occurrence of cut fluff. Note that the polyester in the present invention is a general term for polyesters containing ester bonds in the molecular chain, typified by polyethylene terephthalate, and also includes modified polyesters containing a third component such as isophthalic acid and paraoxyethoxybenzoic acid. Hereinafter, the method of the present invention will be specifically explained using Examples. Example: Highly oriented undrawn polyester yarn obtained by high-speed spinning (birefringence △n 55×10 ^-3 , crystallinity 9.7%)
Using the apparatus shown in FIG. 1 with 230d/48f as the raw yarn supplied, the yarn was drawn and false-twisted under each condition shown in Table 1 to produce a spun yarn-like processed yarn. In addition, under each trial production condition, the yarn supply speed was 100 m/min, and the number of false twists was 1700 times/m. Further, the stretching ratio according to the above formula (1) at a relaxation rate of 55%, which is the processing condition shown in Table 1, was 1.71. Table 1 shows the results of evaluating the uniformity, convergence, yarn form, and strength of the processed yarns obtained under each condition. As is clear from Table 1, the processed yarn obtained in Example 1 of the present invention has good uniformity, convergence, and strength, and the outer layer has a uniform fine crimp and arched loop shape. The yarn had fluff, the inner layer had a core formed of fused filaments, and had a two-layer structure with a spun yarn-like appearance. When this processed yarn was used for the warp and weft and weaved at a warp density of 52/inch and a weft density of 88/inch, the openness during weaving was good, and the finished fabric was dyed in the usual way. As a result, a fabric was obtained which had fine loops without unevenness on the surface of the fabric, had no cut hairs, and had a spun yarn-like appearance and feel. On the other hand, the yarn has a higher relaxation heat treatment temperature than the present invention (Comparative Example 1), a yarn with a low stretching ratio (Comparative Example 2), and both of which are outside the conditions of the present invention (Comparative Example 3). The strength and yarn form were not satisfied at the same time, and the strength was also lower than that of Example 1.

[Table] However, the degree of uniformity is determined by observing the yarn under a load of 0.02g/d with a magnifying glass, and taking the average thickness of the yarn as B.
The number of loops per meter of loops with a thickness of 2B or more was determined as follows. 〇…20 or less, △…21-30, ×…31 or more. In addition, the degree of convergence is set at a yarn speed of 150 m/min and the unwinding tension of the yarn during tube knitting using a Visigraph manufactured by Sanei Sokki Co., Ltd., so that the average tension is 1 g, and a chart as shown in Figure 3 is drawn. The following procedure was performed depending on the number of pieces with an unwinding tension of 5 g or more per 1000 m. 〇...5 or less, △...6-15, ×...16 or more. Furthermore, the yarn morphology was evaluated based on the appearance of the yarn from the clarity of the two-layer structure as follows. 〇...Good, △...Normal, ×...Bad.

[Brief explanation of drawings]

FIG. 1 is a schematic process diagram showing an embodiment of the present invention;
FIG. 2 is a schematic side view of an example of a spun yarn-like polyester processed yarn obtained by the present invention, and FIG. 3 is a graph showing the unwinding tension of the yarn obtained by the present invention. In the figure, 3 is a feed roller, 4 is a relaxing heater, 5 is a first delivery roller, 6 is a stretching false-twisting heater, 7 is a false-twisting spindle, and 8 is a second delivery roller.

Claims (1)

[Claims] 1. Birefringence △n obtained by high-speed spinning is 15 to 80
×10 ^-3 , a highly oriented polyester undrawn yarn with a crystallinity of 20% or less is heat-treated at a temperature of 180°C or less in a relaxed state of 30% or more without contacting with a heating device,
Next, the yarn is stretched at a draw ratio A that satisfies the following formula (1).
A method for producing a spun yarn-like polyester processed yarn, which comprises drawing and false twisting the yarn. A>1.1 (1+a/100) …(1) However, a: Relaxation rate (%)