JPH0140124B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a mixed shrinkage yarn, which is a thick and thin yarn that partially has a thick portion in the direction of the yarn axis, and has different heat shrinkage rates between at least two yarn groups. , its purpose is to
The object of the present invention is to provide a method for easily producing a special polyester yarn that has extremely excellent different dyeing effects and hand-improving effects. Many proposals have been made to make synthetic fibers approach the excellent texture of natural fibers. Among these, silk-like texture has extremely high added value when made into fabric, so many proposals and innovations have been made to bring it closer to natural silk. For example, yarns with irregular cross-sectional shapes,
Manufacturing techniques such as those in which a plurality of yarns with different thermal shrinkage rates are blended, and those in which thick portions of fineness are partially expressed in the yarns are common and widely known. Among these, the mixed shrinkage yarn, which is a mixture of yarns that are thick and thin and have different heat shrinkage rates, has thick fineness parts that are partially expressed in the yarn group, that is, undrawn yarns. Alternatively, the difference in blending ratio between the slightly stretched part and the finely woven part, that is, the stretched part, causes a difference in dye adsorption performance when dyed, and the dark flame part exhibits a delicately blended contrast. Also, due to the difference in fineness between the thick and fine fineness areas, a good slab-like texture is produced. In addition, due to the different heat shrinkage rates, when fabrics are made into fabrics and subjected to relaxation heat treatment, yarn length differences occur between yarns, and this yarn length difference forms small loops on the surface of the fabric, making it difficult to use with conventional synthetic fibers. The flat and slimy feel that was previously seen is gone, and a silky texture with a soft, elegant luster and bulkiness is created. In other words, the differential shrinkage mixed fiber yarn that partially exhibits the large fineness portion is useful as an extremely novel material yarn that produces a composite texture that is a mixture of spun-like performance and silk-like texture. The inventors of the present invention made earnest efforts to develop such a yarn, but found that using conventionally known methods resulted in various problems and it was not possible to obtain a yarn with satisfactory performance. First, even with these high value-added yarns, in response to market needs, supplementary alkali reduction treatment is performed on the fabric, but in this case, some If the difference in chemical treatment effect between the thick-fiber part, which has performance similar to that of undrawn yarn, and the stretched part is too large, only one part will lose weight and a "bug-like" missing part will be formed. Therefore, the yarn to be supplied when manufacturing a differentially contracted mixed fiber yarn in which the large fineness portion is partially expressed is more suitable for high-speed spinning than the normally used undrawn yarn with a low degree of orientation. It is necessary to use undrawn yarn with advanced orientation. However, when highly oriented undrawn yarn is drawn, the heat shrinkage rate of the drawn yarn becomes extremely high.
According to the test results of the present inventors, the heat shrinkage rate of yarn having a large fineness portion is extremely high, exceeding 50 to 60%. It has the disadvantage that the dimensions shrink and become smaller than the initially designed dimensions, and the texture is hard and extremely paper-like. Secondly, as a countermeasure to this drawback, and in order to differentiate the heat shrinkage rate of the yarns, it is necessary to heat treat the yarns to lower the heat shrinkage rate. A generally conceivable method is to carry out heat treatment using a heated grafting plate or a non-contact hollow tube, either subsequently or in a separate step after yarn production. The present inventors also performed heat treatment using this method in an attempt to lower the heat shrinkage rate of the yarn, but found that extremely inconveniences occurred. That is, when a heat treatment area is provided and the yarn is subjected to heat treatment after producing a thick and thin yarn partially having a thick fineness portion, the yarn is passed in contact with a heated bonding plate or a bonding body provided in the heat treatment area. In this case, the shrinkage rate of the yarn decreases, but due to the frictional tension between the heated grafting plate or grafting body and the running yarn, or the shrinkage tension of the fine-grained part due to heat, some parts of the yarn may shrink. A part or most of the thick part that has been developed during heat treatment will be stretched, and the number of thick parts will sharply decrease compared to before heat treatment, and the remaining part will also be divided into thick part and fine part. In other words, if the border with the stretched part becomes unclear and dyed, the contrast effect of light and shade will be drastically reduced. It is easy to think of a method of overfeeding the heat treatment area in order to reduce the tension of the running yarn, but even with this method, the large fineness area will be caused by heat shrinkage of the fine fineness area. The same phenomenon as above occurs due to the tension applied, and when the overfeed rate is further increased, heat treatment unevenness occurs due to the low tension of the running yarn, causing variations in heat shrinkage rate and yarn breakage during stretching. rate becomes extremely high. The behavior of drastic reduction in the thick part due to these heat treatment temperatures is extremely influenced by the heat treatment temperature, and the higher the treatment temperature, the more remarkable the reduction in the thick part is. In other words, the decrease in the thick fineness portion is greater in the low shrinkage yarn than in the high shrinkage yarn. The present inventors solved the above problems,
We came to the conclusion that in order to produce differentially shrinkable mixed fiber yarns that partially have thicker areas, it is necessary to develop a technology that heat-treats the thicker areas once formed in the drawing area without stretching them. We conducted intensive studies focusing on actively utilizing the frictional resistance generated between the heat-treated portion and the thick yarn yarn during heat treatment. As a result, we surprisingly found that (1) by heating the yarn in close contact with a roller with a special surface roughness, it was possible to reduce the heat shrinkage rate without stretching the thick part; 2) Through this method, the present invention was achieved based on the knowledge that, even if a yarn that has been heat-treated and crystallized once is heat-treated again using the conventional method, the large-fineness portion disappears very rarely. It is. That is, in the present invention, the birefringence (△n) is 20×
A yarn consisting of at least two groups of highly oriented polyester undrawn yarns of 10 ^-3 or more and 60 × 10 ^-3 or less is formed so that a large fineness portion is partially expressed in the fiber axis direction in each of the yarn groups. The surface roughness continues to increase.
Winding the yarn group around a heated roller for 1 s or less,
After performing the first heat treatment at a temperature [RT] (°C) within the range shown in the first equation without causing any slippage, only one of the yarns is heated at a temperature [RT] (°C) within the range shown in the second equation. H ₁ ] (° C.), followed by doubling, mixing, and winding. Tg+5≦RT≦Tg+35 (1) RT+15≦H ₁ ≦RT+75 (2) In the formula, Tg is the glass transition temperature (° C.) of the supplied yarn. The polyester feed raw yarn of the present invention can be arbitrarily selected as long as it is a polyester long fiber that can cause netting when stretched using specific conditions or equipment, but among them, ethylene terephthalate It is preferable to use a polyester containing 85 mol% or more of the component as a repeating unit. In addition, when performing alkali treatment or heat processing to improve the texture and feel of the fabric, it is necessary to minimize the shedding or dissolution of the thicker part, and to prevent the thicker part from deteriorating over time. In view of this, it is necessary that the birefringence index (Δn) of the supplied yarn be 20×10 ⁻³ or more. On the other hand, when the birefringence index (△n) of the supplied raw yarn is large, the thick part can be prevented from deterioration due to chemicals such as alkali and over time, but the thick part, that is, the part that has not been stretched or has been slightly The structural difference between the part where the material is drawn and the part where the fineness is drawn is extremely small, and when dyeing is carried out, the adsorption performance of the dye will inevitably be similar, and one of the characteristics is the contrast of light and shade. The birefringence index (Δn) of the supplied raw yarn should be 60×10 ⁻³ or less because it becomes difficult to manufacture the differentially shrinkable mixed fiber yarn of the present invention. Furthermore, the supplied yarns do not necessarily have to have the same degree of orientation, and yarns with different birefringences, finenesses, and cross-sectional shapes may be used as the supplied raw yarns, if necessary. For drawing so that a thick part is partially expressed in the fiber axis direction, any conventionally known method can be used as long as it is a method that can produce thick and thin yarns, for example, by adjusting the drawing temperature,
A method is known in which the stretching ratio is set to special conditions, or a method in which the draw length or tension is varied within the stretching region to create a thick fineness section.
Among these, the thick part is clearly expressed,
Any method can be used without particular limitation as long as it can clearly produce dark and light colored areas when dyed. The first stage heat treatment temperature [RT] used in the formula is the surface temperature of the heating roller during rotation, and is the temperature of the yarn group in which the large fineness portion, which is the gist of the present invention, is partially expressed. It is important to control the heat shrinkage rate, and by changing the first stage heat treatment temperature [RT], it is possible to arbitrarily select the heat shrinkage rate of the yarn to be made into a high shrinkage yarn, and it is also possible to select the heat shrinkage rate of the yarn to be made into a high shrinkage yarn. It is important to perform preliminary heat treatment on the yarn to be subjected to the second heat treatment later, and to suppress the disappearance or shortening of the thick part once formed in the drawing area. It shows extremely high effectiveness. In other words, in this case, by preheating the yarn to be a low-shrinkage yarn using a heating roller at temperature [RT], even if heat treatment is performed at the second heat treatment temperature [H ₁ ], tension will not be generated due to shrinkage in the fine-grained portion. is small,
Moreover, even if heat treatment is performed under tension, a yarn with a low heat shrinkage rate can be produced while maintaining a thick and thin state without stretching the thick portion. For this reason, the heating roller must be positioned before the yarn to be made into a low shrinkage yarn is heat treated at the second heat treatment temperature [H ₁ ], and the heating roller must be positioned at the second heat treatment temperature [H 1 ]. If the yarn is placed after being heat-treated with [H ₁ ], the above-mentioned problems occur and a satisfactory yarn cannot be obtained. The first stage heat treatment (heating roller) temperature [RT] is
When the glass transition temperature of the supplied yarn is Tg (℃),
(Tg+5)℃~(Tg+35)℃,
If [RT] is less than (Tg + 5)°C, when the yarn group is wound around the heated roller, the heat setting effect of the thick part where the thick fineness part is partially expressed in the yarn group will not be sufficient. , the fineness part shrinks in the second heat treatment, making it impossible to produce a low-shrinkage yarn with clear contrast, and the high-shrinkage yarn side has a high heat shrinkage rate, resulting in poor dimensional stability when made into a fabric. Moreover, since it has a hard texture, it is not suitable for the purpose of the present invention. In addition, the first stage heat treatment temperature [RT] is (Tg + 35)
If the temperature exceeds ℃, the heat shrinkage rate of the yarn will be extremely low, and even if the yarn with a low shrinkage rate is heat-treated at the second heat treatment temperature [H ₁ ], the heat shrinkage rate will be lower than that of the high-shrinkage yarn. The difference is small, and when made into a fabric, the difference in heat shrinkage rate between the two yarns is small, resulting in a paper-like texture, and the desired silk-like texture cannot be obtained. The glass transition temperature [Tg] can be measured using a differential scanning calorimeter, etc. For example, when the undrawn yarn used is polyethylene terephthalate,
The glass transition temperature is about 75°C, and the first stage heat treatment temperature [RT] in this case is preferably 80°C or higher and 110°C or lower. In addition, the second stage heat treatment temperature [H ₁ ] applied to the yarn to be made into a low shrinkage yarn is 15% lower than the first stage heat treatment temperature [RT].
By setting the temperature higher by ~75℃, the difference in heat shrinkage between high-shrinkage yarn and low-shrinkage yarn is balanced, and when made into fabric, it has good bulk and a silky texture, and the temperature difference is 15℃. If it is lower than 75°C, the differential shrinkage effect will not be sufficient, and if it is higher than 75°C, not only will the effect of increasing the shrinkage difference be small, but the incidence of yarn breakage will increase rapidly during stretching, which is undesirable. A phenomenon appears. The surface roughness of the heating roller that performs the first-stage heat treatment is determined by heat treatment without stretching the thick-fineness portions that appear in the yarn, that is, without deforming the thick-fineness portions formed in the drawing region. It has an extremely important role in carrying out this. The denser the surface roughness, the more heat treatment is possible without impairing the contrast in shading due to the difference in dye adsorption performance between the thick and fine fineness parts of the yarn group, and it is possible to The surface roughness of the heating roller must be 1s or less to prevent slips from occurring between the heating roller and the roller surface. The surface roughness of the heating roller is more preferably 0.5 s or less, although it varies somewhat depending on the fineness of the yarn, the degree of content of the matting agent, the type of oil agent applied to the yarn, etc. If the surface roughness of the heating roller exceeds 1s, slips may occur between the roller surface and the yarn when the yarn is wound around the heating roller during heat treatment, and slips may occur partially within the yarn group. The thicker part becomes stretched, and as a result, the thicker part disappears or becomes shorter, resulting in an unclear contrast between light and shade, resulting in a yarn with low utility value. Note that "winding on a heating roller" is used here.
refers to winding the yarn around a pair of rollers and separate rollers, or a Nelson roller with an inclined roller.In this case, the tension of the running system is simultaneously applied to the rollers. If it is necessary to nip, it is necessary to wind the yarn until no slip occurs between the roller and the yarn. For example, when winding the yarn around the roller using a separate roller, the yarn 1 If the length of the yarn to be tied to the roller is about 25 cm, it is preferable to wind the yarn 2 to 3 times or more. Further, in order to obtain a sufficient thermal setting effect of the yarn, it is preferable to carry out heating contact for 0.05 seconds or more. In addition, the heat treatment temperature [H ₁ ] of the yarn to be made into a low shrinkage yarn
When performing the second stage heat treatment, the heating body can be a conventionally known method such as a bonding plate, a non-contact heating hollow tube, or a heating pin. Circumferential speed (V ₁ )
In order to _{further enhance the effects of the present invention, it is preferable to set the peripheral speed ratio (V 2 /} V ₁ ) of the focusing roller peripheral speed (V 2 ) to less than 1.0. An example of an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing a specific example of a twisting machine for carrying out the present invention. What is shown in FIG. 1 is an example in which the supply yarns are two yarn groups, and the supply yarns 1 and 1' are sent out by a supply roller 3 via guides 2 and 2', respectively. It is taken up by the stretching roller 5 which rotates at a speed where the peripheral speed ratio of the stretching roller 5 to the supply roller 3 exceeds 1.0, and is stretched between both rollers (stretching area). At this time, the stretching roller 5 also serves as a heating roller, and
is subjected to heat treatment or preheat treatment. A cylindrical friction resistor 4 is disposed between the supply roller 3 and the heating roller 5 which also serves as a stretching roller.
The yarns 1 and 1' are wound around this frictional resistor 4, so that thick fineness portions are partially expressed in the yarn group, and thick and fine yarns are manufactured. Therefore, the heating roller 5 which also serves as a stretching roller
The thick and thin yarn consisting of the two yarn groups drawn and taken by the heating roller 5 which also serves as a drawing roller
Heat treatment or pre-heat treatment is performed. Thereafter, the two yarns are placed on a heating plate 6 provided in an area between the heating roller 5, which also serves as a stretching roller, and the focusing roller 8, and where the circumferential speed ratio of the focusing roller 8 and the drawing roller 5 is less than 1.0. Among the yarn groups, only the yarns to be low shrinkage yarns are brought into active contact, and the other yarns to be high shrinkage yarns are brought into contact with the separation guide 7.
The two yarns are then separated from the heating plate 6 by a doubling guide 9, wound around a converging roller 8, and sent out after being doubled and mixed, and passed through a mixing guide 10 to a pirn 11. It is rolled up. At this time, a heating roller 5 which also serves as a stretching roller
The surface roughness of the yarn must be 1s or less to prevent slips from occurring between the yarns and the thicker yarns. Figure 2 shows the relationship between the temperature [RT] of the heating roller, which is a key component of the present invention, and the thermal shrinkage rate of a thick and thin yarn in which a thick part is partially expressed, measured for a polyethylene terephthalate yarn. The results show that as the temperature [RT] of the heating roller increases, the thermal shrinkage rate of the yarn rapidly decreases. Toray Engineering Co., Ltd. has information about the difference in shading when dyeing, the number and length of thick areas, which are characteristic of differential shrinkage mixed fiber yarns that partially have thick areas.
Measuring with the FYL dye spot measuring device or the Ipnes Tester yarn spot measuring device manufactured by Keizai Kogyo Co., Ltd. enables a much clearer evaluation than evaluations that rely on sensory or visual inspection. Moreover, the thermal shrinkage rate in the present invention is defined as follows. That is, a mixed shrinkage yarn composed of yarns with different heat shrinkage rates is pulled out from the pirn, divided into high shrinkage yarn and low shrinkage yarn, each skeined with a measuring machine, and the weight W (1 /3g/denier)
Measure the initial length l ₀ under the load of . Next, the yarn is immersed in boiling water for 30 minutes under no load to shrink the yarn. After air drying, the length l ₁ after shrinkage was measured again under a load of weight W, and the heat shrinkage rate (WS) was calculated by the following formula. Thermal shrinkage rate (%); WS (%) = l ₀ − l ₁ /l ₀ The effects of the differentially shrinkable mixed fiber yarn obtained by the manufacturing method of the present invention will be described in the examples described later, but conventionally When yarn is heat-treated, its thick part disappears or becomes short, so its application to products has been limited, but by adopting the method of the present invention, it has been possible to create spun-like textures and silk-like textures. This makes it possible to provide a differential shrinkage mixed fiber yarn that exhibits an extremely good composite texture that has both of the following. The present invention will be explained below with reference to Examples. Example 1 The intrinsic viscosity [η] measured at 20°C using a mixed solvent of equal weights of phenol and tetrachloroethane was
By melting polyethylene terephthalate having a molecular weight of 0.65 and changing the take-up speed during spinning through a spinneret, yarns having various birefringence indexes (Δn) were collected. Using the yarn as a feed raw yarn, the temperature [RT] of the heating roller, which also serves as a drawing roller and has a surface roughness of 0.3 s, is set to 100℃ (Tg + 25℃) using the apparatus and drawing method shown in Figure 1. After stretching and heat treatment, only the yarn to be made into a low-shrinkage yarn is actively brought into contact with a heating plate at a temperature (H ₁ ) of 130°C (RT + 30°C), followed by piling, mixing, and winding. The fineness is 75 denier and the number of filaments is 48.
It is a filament, and the birefringence of the thick part (△
Different shrinkage mixed fiber yarns with different n) were obtained. Subsequently, these differential shrinkage mixed fiber yarns are knitted into tubes,
About the tube knitted fabric Sodium hydroxide 20 at 70℃
% aqueous solution for 30 minutes, air-dried, unraveled the yarn from the tubular knitted fabric, and measured and evaluated the rate of decrease in tenacity and the remaining large fineness portion. The evaluation results are shown in Table 1. In addition, regarding the strength reduction rate of the yarn mentioned here, it was treated with a sodium hydroxide aqueous solution, and after air drying,
The threads were unwound from the tubular knitted fabric, and the strength was measured using an Instron tensile tester to determine the rate of decrease in strength compared to before treatment with an aqueous sodium hydroxide solution. In addition, regarding the remaining large fineness portions that appear in the differentially shrinkable mixed fiber yarns, the tubular knitted fabric was treated with an aqueous sodium hydroxide solution in the same manner as above, and 10 cm of the tubular knitted fabric after the treatment was shaped into a cylindrical shape. After wrapping it around a core and rotating it for 5 hours using an ICI pilling tester, the tubular knitted fabric was taken out and the degree of shedding of the thicker part was visually evaluated.

[Table] Example 2 Among the undrawn yarns collected in Example 1, the spinning speed was
3000m/min, and the birefringence (△n) is 38.9×
Using the undrawn yarn of ^10-3 as the supplied raw yarn, use the same method as in Example 1 to set the temperature of the heating roller that also serves as a drawing roller [RT], and reheat the yarn to be made into a low shrinkage yarn. By variously changing the temperature [H ₁ ],
A mixed shrinkage yarn with a fineness of 75 denier and a number of filaments of 48 was obtained. Using these different shrinkage blend yarns as the warp and weft yarns, Nitsu Sanjetsu 1000
(Product name), the resulting fabric is scoured, preset, alkali treated, and dyed, and 10 panelists evaluate the fabric for its warmth, spun-like properties, and luster. , contrast, etc. were evaluated, and the overall evaluation results are shown in Table 2.

【table】

[Table] Example 3 The same undrawn yarn as in Example 2 was used as the supplied raw yarn, and the surface temperature [RT] of the heating roller that also served as a drawing roller was determined using the same method as in Example 1.
The temperature of the heating plate [H ₁ ] to 100℃ (Tg + 25℃) and heat treatment on the yarn to be made into low shrinkage yarn is 130℃.
(RT+30°C), and variously changed the surface roughness of the heating roller that also served as a drawing roller, to obtain a differentially shrinkable mixed fiber yarn with a fineness of 75 denier and a number of filaments of 48. The fabrics obtained by weaving and dyeing this differentially shrinkable mixed fiber yarn in the same manner as in Example 2 were evaluated by 10 panelists, focusing on the contrast of shading, and the evaluation results are shown in Table 3. Indicated.

【table】 [Brief explanation of drawings]

Fig. 1 is a schematic diagram of a drawing and twisting machine which is an example of a device for producing a differentially shrinkable mixed fiber yarn containing a large fineness portion according to the present invention, and Fig. 2 shows the surface temperature [RT] value of the heating roller and the large fineness. FIG. 1, 1': Supply yarn, 2, 2': Guide, 3: Supply roller, 4: Frictional resistor, 5: Heating roller that also serves as a stretching roller, 6: Heating plate, 7: Separation guide, 8: Convergence Roller, 9: Doubling guide, 1
0: Mixed fiber guide, 11: Pern.

Claims (1)

[Claims] 1. Birefringence (△n) is 20×10 ^-3 or more, 60×10 ^-3
A yarn consisting of at least two groups of the following highly oriented polyester undrawn yarns is drawn so that a large fineness part is partially expressed in the fiber axis direction in each yarn group, and then the surface roughness is reduced to 1s. The yarn group is wound around a heating roller as follows, and the temperature [RT] is within the range shown in equation (1) without substantially slipping.
After performing the first heat treatment at (°C), one of the yarns is subjected to the second heat treatment at the temperature [H ₁ ] (°C) shown in equation (2), and then the yarn is mixed. A method for producing a differentially shrinkable mixed yarn characterized by spinning and winding. Tg+5≦RT≦Tg+35 (1) RT+15≦H ₁ ≦RT+75 (2) In the formula, Tg is the glass transition temperature of the supplied yarn.