JPH0223604B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a substantially crimp-free polyester filament mottled yarn, and more particularly to a mottled yarn suitable as a yarn for silk-like textiles and knitting.

The object of the present invention is to obtain woven or knitted fabrics having silk-like natural patterns (patches). In general, even though it is called mottled thread, it does not mean that it is sufficient if it has irregularities in thickness, dyeing, etc., and it cannot be called a versatile mottled thread unless at least the following two requirements are satisfied. In other words, the first requirement is the physical properties of the yarn, and the yarn must have sufficient physical properties to be able to pass through the process stably and withstand the weaving and knitting processes as well as the subsequent dyeing and finishing process. , the yarn has sufficient durability for practical use. For example, there may be spots here and there along the length of the yarn, but the spots tend to stretch, making it difficult to weave or knit, or the physical properties of the spots and normal sections may be so different that wrinkles may appear in the fabric during the dyeing and finishing process. There must be no defects in the physical properties of the yarn. The second requirement is the shape of the spots, and each woven or knitted fabric targeted for development requires a unique shape of spots. In other words, silk fabrics have a mottled pattern that is suitable for silk fabrics, and woolen fabrics have a mottled pattern that is suitable for woolen fabrics, and if this pattern is not satisfied, it feels strange. Therefore, when developing spotted threads, it is also important to adjust the spot format. below,
I will explain the speckle format in detail. In general, the unevenness of a yarn is mainly determined by the shape of each single fiber that makes up the yarn, especially the fiber length and the history of the construction process. For example, silk is obtained by gathering silk threads, which are relatively uniform and long fibers, and pulling them together, and the spots that can occur during this process are rare, and even if spots do occur, they are highly uniform. The length of the patch is relatively long. The pattern of unevenness in silk is that there are relatively uniform uneven areas within a uniform thread at long intervals, and the length of the uneven areas is relatively long. When we are trying to obtain silk-like mottled threads using polyester filament, by meeting these requirements for the mottling of silk, we can obtain threads that exhibit a natural and harmonious appearance as a silk material. On the other hand, since spun yarn has a short fiber length, the frequency of unevenness is high, and the length of the unevenness is also short and the degree of uniformity is low. Of course, there are also spun yarns such as cotton, wool, and hemp, and each has a unique mottled appearance due to differences in fiber length and manufacturing process.

Now, as a method for generating unevenness in polyester filament, there is a method of drawing an undrawn yarn at a low draw ratio to obtain a mottled yarn in a state including a stretched part and an unstretched part, and also drawing at a low draw ratio. There is a method in which the stretching step is carried out in two stages, such as the method described in JP-A-52-103523 and JP-A-55-142716. However, stretching at these low draw ratios alone cannot satisfy the requirements for speckled yarn, especially for silk materials. The reason for this is that when an undrawn yarn is drawn at a low draw ratio, a mottled yarn consisting of a stretched portion and an undrawn portion is generally obtained, but this yarn is not stretched sufficiently and is therefore extremely easy to stretch. At the same time, it may also stretch well in some areas. For example, as shown in Japanese Patent Application Laid-Open No. 142716/1983, the elongation of the yarn is extremely high, 75 to 120%, which is very inconvenient in the weaving and knitting process. Another disadvantage is that the thermal properties of the stretched and unstretched areas are too different, resulting in stiffness during the textile dyeing process. That is, by lowering the draw ratio, even though mottled yarns can be obtained formally, yarns having sufficient yarn physical properties cannot be obtained. Next, requirements for unevenness due to low stretching ratios will be described. When an undrawn yarn is drawn at a low draw ratio, the unevenness repeats frequently and the yarn is poorly balanced. In other words, the unevenness obtained at a low draw ratio is not the form of the unevenness of the silk material, but the unevenness of the spun yarn material. This is the realm of form. One example is the example of JP-A-52-103523, in which the drawing is divided into two stages, but the drawing is carried out at a low drawing ratio, and the degree of uniformity of the yarn obtained at this time is shown. U% is
It is stated as 13%. This value is U% of spun yarn
A large U% value indicates that the yarn is poorly balanced, but at the same time, there is a large difference between the thin and thick yarn sections, and there are many repeated irregularities. It means. Japanese Patent Publication No. 1427116
The publication is an example of one-stage stretching with a low stretching ratio,
The obtained yarn has 10 to 40 spots per meter,
The length of the spots is said to be less than 40 mm, and there are many repeating spots. As described above, in the conventional production of speckled yarn using a low draw ratio, it is not possible to obtain speckled yarn of silk material that satisfies both the yarn physical properties and the speckled requirements.

The present invention has been achieved through ingenuity and consideration in order to fully satisfy these requirements, and specifically relates to a mottled yarn made of polyester filament of silk material and a method for manufacturing the same.

First, the characteristics of the yarn (spotted yarn) of the present invention will be explained.

(1) The yarn of the present invention has a high degree of symmetry The yarn of the present invention (polyester multifilament) has a normal part (stretched part) and uneven parts (including unstretched part and partially stretched part) in its length direction. Therefore, the normal part is a sufficiently drawn yarn with a very high degree of symmetry, and because it is sufficiently drawn, it has sufficient yarn physical properties. In addition, the patchy area is not only composed of patchy fibers, that is, undrawn fibers or partially drawn fibers, but also includes sufficiently drawn fibers (normal fibers). Therefore, it is possible to obtain a high degree of uniformity and sufficient yarn physical properties. In general, speckled fibers are undrawn thick fibers or easily dyed fibers, but their physical properties are generally easy to stretch and have large heat shrinkage, so they can be used in combination with normal fibers (drawn fibers). As a result, the uniformity of the yarn as a whole is improved, and the physical properties of the yarn as a whole are also normal due to the action of the fibers, making it difficult to stretch and causing small contractions. In other words,
By composing the mottled areas not only with mottled fibers but also with normal fibers, it is possible to obtain the required degree of symmetry as a silk material, which improves process stability during fiber knitting and eliminates stiffness during finishing. Twisting and twitching phenomena can be prevented. here,
It is preferable that the proportion of the mottled fibers in the mottled area is smaller, and the physical properties of the mottled fibers are closer to those of normal fibers. FIG. 1 is a schematic diagram showing the structure of the uneven portion according to the present invention, in which the yarn is cut in the length direction (20 or more cuts).The structure of the uneven portion according to the present invention can be roughly divided into two types Figure 1 A, B). Figure 1A shows one type, and as is clear from the drawing, in addition to the normal drawn fibers 6, the type 1 includes undrawn fibers 7 and partially drawn fibers (for example, natural draw ratio ND
It also contains fibers) 8 which have been stretched by about 50 to 60%. It is preferable that the proportion of the undrawn fibers 7 occupying the mottled areas of the silk material as mottled threads is small, and the average number of undrawn fibers 7 is preferably 30% or less, preferably 10% or less in the mottled areas. Another type of mottling according to the present invention is type 2 shown in FIG. 1B, and as can be seen from the figure, type 2 is a case where the partially drawn fibers 8, which are almost diametrically stretched, form mottled fibers. Type 2 is a case in which it is easier to obtain both filament physical properties and uniformity than type 1, but in this case as well, it is better to have fewer spotted fibers. In both type 1 and type 2, the percentage of spotted fibers is 55% on average.
It is preferably less than 40%. In addition,
Containing normal fibers is an essential condition for type 2 as well. In general, type 2, in which thick fibers are not mixed, is better than type 1 in terms of the uniformity of the mottled areas, but type 1 and type 2, which are mixed in the lengthwise direction of the yarn, may not exist as mottled areas. In fact, it gives depth and variety to the texture of the woven and knitted fabric, giving it a natural feel. However, if there is too much type 1 in the mottled area, the uniformity of the threads will be poor, which is not a desirable direction for silk material. preferable. Here, the reason why normal fibers (drawn fibers) are essential in the structure of the mottled areas in the present invention is to cope with the fact that silk materials are generally processed through alkali weight loss processing. In other words, the lower the molecular orientation of the fiber, the faster the alkali weight loss rate, and if the mottled portion is composed only of mottled fibers (unstretched or partially stretched fibers with low molecular orientation), some of the fibers may disappear and create pinholes. In order to prevent this, normal fibers (drawn fibers) are incorporated into the patchy structure.

(2) The yarn of the present invention has fewer repeating spots It is important for the thread of silk material to have long intervals between spots and to have a low frequency of repeating spots. This is a natural phenomenon that can occur when long fibers (silk) are bundled into threads, and meeting this requirement in the development of silk materials will lead to the creation of true silk-like woven and knitted fabrics.
According to the research of the present inventor, in order to obtain a silk-like woven or knitted fabric, the interval between spots is at least one per body length or garment length, and numerically approximately
One spot per 1 meter is the maximum number of repeats for silk material as a speck thread, and although it is preferable that the number of repeats is smaller than this, the lower limit should be one every 900 meters. If a fabric is woven using only threads with one mottled number per meter, the number of mottled spots will be too large to be considered to be the mottled texture of silk material. By using it in combination with , it is possible to obtain a woven or knitted fabric with apparently fewer spots. Of course, it is possible to obtain a silk-like woven or knitted fabric using only the mottled threads if the number of mottled repetitions is sufficiently small. Also, if the number of spots is very small, for example, one spot per 10,000m,
It can be seen as a defect in woven or knitted fabrics rather than silk-like spots. Therefore, typically 1m
From 1 to about twice the fiber length of silk (approx.
It is important that the yarn has one spot per 900 m), and the yarn of the present invention satisfies this requirement.

(3) The yarn of the present invention has relatively long irregularities. The irregularities are short when measured in the longitudinal direction of the yarn. For example, irregularities such as 3 to 8 mm or 20 to 40 mm are caused by silk, which is a long fiber. The spots are unnatural. Relatively short spots may be mixed in to give a silky appearance, but the spots must be long enough to allow the collection of long fibers to be recognized. Specifically, if you are aiming for silk, you need spots that exceed the fiber length of the spun yarn, and numerically speaking, you need spots with a length of about 70 mm or more. Yes, in this case, the long spot is 200mm.
There is no problem even if the spots are as above. and,
It is okay to have short spots mixed in as silk-like spots, but in order to recognize that they are long fibers, the long spots with a length of 70 mm or more should be at least 1/10 of the total spot, preferably 2 /10 or more is preferable.

Although the structure, physical properties, and type of mottling of the mottled thread according to the present invention have been individually explained above, these are actually related to each other. In other words, the uniformity of the silk-like threads according to the present invention is
The individual factors mentioned above (difference in thickness between plaques and normal areas, spacing between plaques, and length of plaques) should be adjusted so that 0.7%≦U%7%.

Next, a method for producing spotted yarn according to the present invention will be explained.

FIG. 2 is an example of a drawing machine used for producing the spotted yarn of the present invention. R ₁ , R ₂ , R ₃ are each the first
roller, second roller, third roller, U ₁ ,
U ₂ and U ₃ are the surface speed of each roller, PH
represents a plate heater, S represents a spindle winder, 1 represents an undrawn polyester yarn, and L ₁ and L ₂ represent the first and second drawing zone lengths, respectively. Moreover, FIG. 3 shows the stress-strain curve of the undrawn polyester yarn. ε _AA indicates the strain position (U ₂ /U ₁ =1+ε _A ) corresponding to the first-stage stretching ratio, and ε _B indicates the strain position (U ₃ /U ₁ =) corresponding to the total stretching ratio after the second stage stretching.
1+ε _B ), and ε _ND indicates natural draw strain. In the practice of the present invention _, the undrawn polyester yarn ₁ is supplied from the first roller _R1 shown in _FIG . Leads to ₂ .
At this time, what is important in the present invention is not to stretch the undrawn yarn uniformly, but to stretch it non-uniformly. FIG. 4A is a schematic diagram of a yarn that has been stretched non-uniformly. In the figure, 2 is a well-stretched drawn yarn section, and 3 is an undrawn (partially stretched) yarn section that has not been stretched well. shows. This kind of condition is
As shown in the above equation, in addition to the low stretching ratio, the temperature during stretching is also relevant. That is, when the temperature of the stretching section is high, uniform stretching occurs, and when the temperature is low, non-uniform stretching occurs.In the present invention, a temperature of room temperature to 90° C. is used as the first stage stretching temperature. In addition, in order to maintain the first stage stretching temperature, R ₁
may be used as a heating roller, or a plate heater may be provided between _R1 and _R2 . What is important in FIG. 4 is that the lengths of the undrawn portions vary, and that the boundaries between the undrawn portions and the stretched portions do not coincide with the boundaries between the undrawn and stretched fibers constituting the yarn. That is, it is preferable that the boundaries between unstretched and stretched are shifted for each fiber. In extreme terms, a portion of the warp-drawn fibers may be inserted into the entire undrawn portion. These are essential for reducing the repetition of irregularities, increasing the uniformity of the yarn, and obtaining sufficient yarn physical properties. Such a yarn morphology can generally be achieved by combining a low draw ratio and a low drawing temperature.

Next, the second stage of stretching will be described. The second stage drawing is achieved by further stretching the yarn obtained in the first stage drawing between R ₂ and R ₃ . A and 4 in Figure 4
The relationship B in the figure schematically shows the behavior from the first stage stretching A to the second stage stretching B in the present invention. That is, the relatively short undrawn yarn obtained in the first stage of drawing is sufficiently stretched in the second stage to become a drawn yarn (4 in B indicates that portion).
The effect of this is to lengthen the distance between the mottled areas, in other words, to obtain a thread with fewer mottled repetitions, which is required as a mottled thread for silk material. In the second stage stretching, fibers that have been fully stretched (normal fibers) over some or all of the relatively long unstretched portions obtained in the first stage stretching, and The yarn is drawn so that a portion (uneven portion) that constitutes the thread is formed with insufficient fibers (uneven fiber) (5 in B indicates the portion). The reason for achieving these is
Even if the stretching ratio is the same, short undrawn yarns are sufficiently stretched, but long yarns pass through the second stretching section without being sufficiently stretched. That is, the short undrawn portions disappear and become drawn filaments, and only the particularly long undrawn fibers in the long undrawn portions are not sufficiently drawn and become patchy fibers. It is important that the second-stage stretching conditions to achieve this satisfy a value U ₃ /U ₁ >1+ε _ND that is sufficient to eliminate at least a part of the unstretched portion.

The basic conditions for producing spotted yarn according to the present invention have been described above, but these alone are not sufficient to stably produce spotted yarn of silk material or to obtain yarn of good quality. The material, stretching equipment, stretching conditions, etc. must be considered.

First, the undrawn yarn will be explained. The _εND of the undrawn yarn can be easily changed by changing the composition of the polymer, the degree of polymerization, and the winding speed during spinning. The relationship between this ε _ND and spots is as follows. When the ε _ND is large, it is easy to obtain mottle threads in which the macules and normal parts are clearly defined, and the intervals between the macules are long. On the other hand, those with a small ε _ND have the advantage of less change over time and less strain change during stretching, making them easier to handle and less likely to break the yarn, but they also have the advantage of less clarity between patchy areas and normal areas, and uneven spacing between patches. The problem is that it is difficult to obtain long ones. In the present invention, it is preferable that there is a clear distinction between the plaque and the normal region, and that the distance between the plaques is long. Therefore,
The undrawn yarn used preferably has ε _ND ≧0.35. More preferably, it is also excellent in handleability.

1.5≦ε _ND ≦3.0 is appropriate.

Next, the stretching device will be explained. The main factor in the stretching equipment is the stretching zone length, and the first stretching zone length
L ₁ is involved in the length relationship in the structure of variegated filaments, and the longer L ₁ is, the longer the variegated and normal areas are obtained. When producing silk threads, it is important that the length of the mottled portion is at least 70 mm or more, which is L ₁ . Specifically, the length of _L1 needs to be 70 mm or more, preferably 100 mm or more.
The second drawing zone table _L2 is mainly concerned with the stability during manufacturing, the structure of the mottles and the spacing between the mottles. Also, if L ₂ is short, thread breakage is likely to occur.
L These problems are resolved when ₂ becomes relatively long. However, if it is extremely long, the ability to remove unstretched portions will be significantly impaired, resulting in a yarn without unevenness, so it is important in the present invention that _L2 be long to some extent. This relationship does not affect _L2 alone, but is related to the undrawn yarn used, the first drawing zone length _L1 , and the drawing conditions.
An appropriate L ₂ in the present invention is expressed in this relationship as follows: L ₁ ≦L ₂ ≦L ₁ × {α(1+ε _ND )/1−α−1} However, U ₂ /U ₂ ≧1+ε _ND , α=1/ε _ND ×U ₂ - U ₁ /U ₁ . In addition, when an obstacle is provided between R ₁ and R ₂ and the first stage stretching is performed between the obstacle and R ₂ , the actual distance L ₁ is the distance between the obstacle and the second roller. Further, for each roller, a roller with a roughened surface, such as a matte roller, is more suitable than a roller with a smooth surface.

Next, the stretching conditions will be described. Stretched part 2 and unstretched part 3 as shown in FIG. 4A in the first stage stretching
In order to obtain this, the undrawn yarn must not be pulled until it is completely stretched, and non-uniform stretching must occur. The conditions are as described above, U ₂ /U ₁ ≦1+ε _ND and stretching temperature: room temperature to 90°C. Also, U ₂ /U(1) is related to the frequency of spots,
In general, the larger the value of U ₂ /U ₁ , the less frequently obtained. The second stage stretching is related to the frequency of mottling and the composition of the mottling. When the value of U ₃ /U ₁ is small, the frequency of spots is high, and the proportion of patch fibers in the spots becomes large. A high U ₃ /U ₁ value is required to eliminate a portion of the unstretched portion and obtain normal fibers and some uneven fibers that are not sufficiently stretched from the unstretched portion.
It is important that the value used in the present invention is at least U ₃ /U ₁ >1+ε _ND . Further, it is preferable to use a temperature of 85 to 170°C during the second stage stretching. This temperature is necessary for the mottled yarn to withstand the hot water distortion that it undergoes in post-processing steps (for example, dyeing) after knitting and weaving, and to obtain a woven or knitted fabric with excellent surface condition.

Next, details of the present invention will be explained using examples and comparative examples.

Example 1 Polyethylene terephthalate was spun and wound at 1900 m/min, 200 denier/36 filament, ε _ND
= 1.51 undrawn yarn was obtained. This was operated using the stretching machine shown in FIG. 2 under the following conditions.

1st stage stretching L ₁ = 400mm, U ₁ = 200m/min,
U ₂ = 484m/min, stretching temperature 30℃ (U ₂ /U ₁ =
2.42, α=0.94) Second stage stretching L ₂ = 1600mm, U ₃ = 572m/min,
Stretching temperature: 120° C. (U ₃ /U ₁ =2.86) The obtained yarn had no crimp and was apparently uniform, and the details of the physical properties of the mottled yarn were as follows.

Elongation: 14% U%: 3.1% Length of spots: 68% are over 70 mm, 21% are over 200 mm Interval between spots: Average 8.1 m (20-30 m for long ones) Type of spots: 40 types are type 1 %, type 2 is 60%, and the proportion of undrawn fibers in type 1 is 7%. The amount of drawn fibers in the entire uneven area was 73%, and the total amount of undrawn and partially drawn fibers was 27%. Comparative Example 1 The same undrawn yarn as used in the previous example was drawn under the following conditions.

1st stage stretching L ₁ = 400mm, U ₁ = 200m/min,
U ₂ = 366 m/min, stretching temperature 30°C (U ₂ / U ₁ =
1.83, α=0.55) Second stage stretching L ₂ = 1600mm, U ₃ = 476m/min,
Stretching temperature: 120° C. (U ₃ /U ₁ =2.38) The physical properties of the obtained yarn were as follows.

Elongation: 40-120% Many unstretched parts remain in the first stage, and there are parts with very high elongation and parts that are easily stretched.

U%: 11.5% Spots: The proportion of unstretched fibers was high, and there were quite a few spots that stretched slowly.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of an example of a mottled part of a mottled thread according to the present invention, where A is a type 1 mottled part;
B shows a type 2 mottled area, and in the drawing, 6 shows a normal drawn fiber, 7 shows an undrawn mottled fiber, and 8 shows a cross section of a partially drawn (incompletely drawn) fiber. FIG. 2 is a flow sheet for an example of a drawing machine used to obtain the yarn of the present invention, where R ₁ , R ₂ , R ₃ are rollers, U ₁ , U ₂ , U ₃ are R ₁ , R ₂ , R is the surface speed of each roller corresponding to ₃ , S is the spindle winder,
PH is a plate heater, _L1 is the length of the first drawing zone, _L2 is the length of the second drawing zone, and the undrawn yarn 1 is supplied from _R1 . Figure 3 shows the relationship between stress and strain in undrawn yarn, where ε _A is the calculated strain position that satisfies U ₂ /U ₁ = 1 + ε _A , ε _ND is the natural draw strain, and ε _B is the breaking strain. . FIG. 4A is a schematic diagram of the yarn after the first stage drawing, in which 2 is the drawn portion, 3
4 is an undrawn or partially stretched portion, and B is a schematic diagram of the yarn after second-stage drawing of the yarn in A.
3 of the same A is the stretched portion, and 5 is the uneven portion of the 3 of the same A that remains unstretched or partially stretched.

Claims (1)

[Scope of Claims] 1. A speckled yarn made of non-crimped polyester multifilament, the yarn has irregularly speckled portions in its length direction, and has U% of 0.7 to 7%, and the speckled yarn has consists of 45% or more (number ratio) of drawn fibers and less than 55% (number ratio) of undrawn or partially drawn fibers, and 30% or less (number ratio) of undrawn fibers in uneven areas A polyester filament mottled yarn characterized in that it contains mottled areas that account for 60% or less (number ratio) of the total mottled areas. 2. The polyester filament mottled yarn according to the preceding item, characterized in that there is one mottled part per 1 to 900 m in the length direction of the filament. 3. The polyester filament mottled yarn defined in each of the preceding items, characterized in that each mottled part has a length of 70 mm or more, which accounts for 10% or more (number ratio) of the entire mottled part. 4 In item 1, the unstretched or partially stretched fibers in the mottled areas account for 40% or less, the unstretched fibers in the mottled areas account for 10% or less, and the mottled areas containing unstretched fibers are relative to the overall mottled areas. A polyester filament mottled yarn characterized by having a content of 40% or less. 5. The polyester filament mottled yarn according to item 3, characterized in that the mottled portion with a length of 70 mm or more is 20% or more of the total mottled portion. 6 Polyester multifilament undrawn yarn with natural draw strain (ε _ND ) of 0.35 or more at room temperature
First stage stretching at 90°C with a stretching ratio of 1+ε _ND or less,
This yarn is made of non-crimped polyester multifilament and is then drawn in a second stage at a temperature of 85 to 170°C at a draw ratio exceeding 1+ε _ND. has part U
% is 0.7 to 7%, and the spots are drawn fibers 45
% or more (number ratio) and unstretched or partially stretched fibers
Less than 55% (percentage in number) of undrawn fibers in the uneven areas, less than 30% (percentage in number) of undrawn fibers in the uneven areas, and less than 60% (percentage of pieces) of uneven areas containing undrawn fibers in the overall uneven areas. A manufacturing method for polyester filament mottled yarn. 7 In the previous section, the first stage stretching is performed with a stretching zone length (L ₁ ) of 70 mm or more, and the second stage stretching is performed with a stretching zone length (L ₂ ) of L ₁ ≦L ₂ ≦L ₁ × {α (1 + ε _ND )/1 -α-1}
, (where α=1/ε _ND ×second roller speed−first roller speed/first roller speed).