JP2007321273A - Polyester combined filament yarn - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyester combined filament yarn satisfying both high strengths and impact absorbing properties. <P>SOLUTION: The polyester combined filament yarn comprises at least two species of polyester-based filaments and satisfies the following items (a)-(d) at the same time: (a) ≥4.0 cN/dtex strength, (b) ≥30% elongation, (c) 5-10% elongation at the second yield point and (d) 0.5-1.0 cN/dtex strength between the first yield point and the second yield point. The polyester combined filament yarn is suitable for safety belts and safety nets used in carrying out height works such as construction works, electrical works and the like, or materials for automobile sheet belts and the like. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a new polyester blend suitable for safety belts, safety nets, or seat belts for automobiles, which is used when performing high-place work such as construction work and electrical work, and has high strength and excellent shock absorption. Related to yarn.

  Originally, the maximum characteristics required for safety belts for safety work, safety nets for automobiles, and seat belts for automobiles are to absorb and mitigate the impact force applied to workers and passengers when falling or colliding, that is, to absorb impacts. Thus, the impact force due to the collision is reduced. In order to satisfy such performance, several proposals have been made for fibers used in this field until now.

  For example, in JP-A-1-298209 (Patent Document 1), polyester having a high intrinsic viscosity is discharged from a discharge hole having a large land length / hole diameter ratio into a high-temperature atmosphere, and the fiber after cooling and solidification is 3000 m / min. Taking up at the above high speed, the elongation at the first yield point of the load elongation curve of the resulting polyester fiber is less than 5%, the elongation at the rise point is 5% or more and less than 30%, and the impact energy is continuous. There has been proposed a method for producing a polyester fiber that can be absorbed smoothly and smoothly. However, the fiber obtained by this method has insufficient breaking strength. For example, when used as a safety belt, the amount of fiber used must be increased to satisfy the required breaking strength of 1830 kg or more. As a result, it has been found that not only the handleability is deteriorated but also the maximum impact load at the time of the fall prevention is increased.

  On the other hand, Japanese Patent Laid-Open No. 5-321062 (Patent Document 2) discloses that after processing a highly shrinkable polyester fiber having a boiling water shrinkage of 25% or more and a thermal stress value of 0.2 g / d or more into a fiber rope, There has been proposed a method for manufacturing a safety rope that can be contracted to effectively absorb impact energy. However, in this method, shrinkage spots are likely to occur during heat shrinkage, resulting in a decrease in the breaking strength of the rope obtained, and an increase in the rise point of the load elongation curve, resulting in excessive elongation for absorbing impact energy. There is a problem of becoming too much.

  Japanese Patent Laid-Open No. 9-143816 (Patent Document 3) proposes a polyester fiber obtained by high relaxation heat treatment after stretching at a high magnification using a polymer obtained by copolymerizing a third component. However, in this method, in order to obtain sufficient breaking properties, it is necessary to make the copolymer polymer have a very high intrinsic viscosity. Since such a polymer generally has a low melting point, a method such as solid phase polymerization at a high temperature is adopted. It is difficult to adopt a general production process.

JP-A-1-298209 Japanese Patent Laid-Open No. 5-321062 JP-A-9-143816

  The present invention has been made in view of the prior art as described above. The purpose of the present invention is polyester blended yarn having a high strength and an excellent shock absorption performance, particularly high-place work such as construction work and electrical work. It is an object of the present invention to provide a novel polyester blended yarn suitable for a safety belt, a safety net, an automobile seat belt, or the like used when performing.

The object of the present invention as described above is achieved by a polyester mixed yarn having the following configuration.
That is, the polyester blended yarn of the present invention is a polyester blended yarn comprising at least two kinds of polyester filaments and satisfying the following (a) to (d) simultaneously.
(A) Strength 4.0 cN / dtex or more (b) Elongation 30% or more (c) Secondary yield point elongation 5-10%
(D) Strength from the first yield point to the second yield point 0.5 to 1.0 cN / dtex

A preferred embodiment of the polyester mixed yarn of the present invention as described above has an intrinsic viscosity of 0.75 to 1.00, a polyester filament (A) having a strength of 5.5 cN / dtex or more, 40 to 70% by weight, isophthalic acid and It is a polyester mixed yarn comprising 60 to 30% by weight of a highly shrinkable polyester filament (B) comprising a copolyester having an intrinsic viscosity of 0.5 or more obtained by copolymerizing 8 to 15 mol% of a bisphenol A compound.
The polyester mixed yarn is preferably made of fibers having an average single yarn fineness of 3 dtex or less.

  The polyester mixed yarn of the present invention can achieve both high strength and impact absorption performance. That is, since the polyester blended yarn has high strength and excellent impact absorbability, it is particularly suitable for safety belts, safety nets, seat belts for automobiles, etc. used when working at high places such as construction work and electrical work. It is suitable as a material.

The polyester blended yarn of the present invention is a blended yarn composed of at least two types of polyester filaments, and has a strength of 4.0 cN / dtex or more (preferably 5.0 to 7.0 cN / dtex), elongation. It needs to be in the range of 30% or more (preferably 30 to 50%). When the strength is less than 4.0 cN / dtex or the elongation is less than 30%, the fracture resistance (silk factor) is small, and the durability required for the above applications is insufficient, and the object of the present invention is achieved. I can't.
Here, the strength and elongation refer to the strength and elongation at break of the yarn, measured by conducting a tensile test according to JIS L-1013 in the state of the mixed yarn.

  Further, the polyester blended yarn of the present invention needs to have a secondary yield point elongation of 5% or more and 10% or less in the load-elongation curve (stress-strain curve) shown in FIG. When the secondary yield point elongation is less than 5%, it is difficult to sufficiently absorb the target impact force of the present invention, and the impact force is applied to the net using this fiber in the same manner as a normal high-strength polyester fiber. It will be passed directly to the user from the rope or belt. On the other hand, when the secondary yield point elongation exceeds 10%, the dimensional change when absorbing the impact is too large, so that secondary disasters such as a collision with another nearby obstacle may occur depending on the usage conditions. It is easy to cause and is dangerous. Here, the “second yield point” is the second inflection point (stress-strain curve) in FIG. 1 obtained by conducting a tensile test in accordance with JIS L-1013. 2) in 1 and “second yield point elongation” means the elongation percentage (%) of the yarn with respect to the original length before the measurement at that time.

  Furthermore, in the polyester fiber of the present invention, the strength of the first yield point to the second yield point shown in FIG. 1 needs to be 0.5 cN / dtex or more and 1.0 cN / dtex or less. When the strength is less than 0.5 cN / dtex, a processed product using the polyester blended yarn is easily deformed by a slight external force and has very poor dimensional stability. When the strength exceeds 1.0 cN / dtex, the stress generated upon impact is too high, and the user's protection due to the impact absorption that is the object of the present invention becomes insufficient. Here, the “strength from the first yield point to the second yield point” refers to the first inflection point (first yield point: 1 in FIG. 1) in the load-elongation curve of the blended yarn. Strength range defined by the maximum and minimum values of strength (stress) until the second inflection point (second yield point: 2 in FIG. 1) (including the gradient between them). . That is, “the strength of the first yield point to the second yield point is 0.5 to 1.0 cN / dtex” means that the first yield point to the second yield point in the load-elongation curve are reached. This means that the yarn strength is always within the range of 0.5 to 1.0 cN / dtex, and does not deviate from this range.

  The one-component filament (A) constituting the polyester blended yarn of the present invention is mainly a polyester whose main repeating unit is ethylene terephthalate, and other components are contained in a proportion of 5 mol% or less based on the total acid component. It may be copolymerized. Examples of such copolymer components include isophthalic acid, phthalic acid, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid, tetramethylene glycol, trimethylene glycol, diethylene glycol, neopentyl glycol, bisphenol A, 2,2-bis. (4-Hydroxyethoxyphenyl) propane and the like can be mentioned, and as the constituent polymer of the filament (A), a polyethylene terephthalate homopolymer containing no copolymerization component is particularly preferable.

  In the present invention, the filament (A) has an intrinsic viscosity (measured at a temperature of 35 ° C. using o-chlorophenol as a solvent, the same shall apply hereinafter) of 0.75 to 1.00 and a strength of 5.5 cN / It is preferable that it is dtex or more. That is, the intrinsic viscosity of the filament (A) is desirably in the above range in order to realize sufficient strength and breaking resistance (silk factor) for the mixed yarn. When the intrinsic viscosity is less than 0.75, it is not preferable because resistance to breakage (silk factor) is hardly exhibited. On the other hand, when the intrinsic viscosity exceeds 1.00, it becomes very difficult to produce such a filament itself, and it is difficult to produce it commercially. Especially, the range of a more preferable intrinsic viscosity is 0.90-1.00. Moreover, in order to make the yarn strength after mixing with the filament (B), which is the other component of the mixed yarn, sufficient, the strength of the filament (A) is preferably 5.5 cN / dtex or more.

  The other component filament (B) constituting the polyester blended yarn of the present invention is a polyester whose main repeating unit is ethylene terephthalate, and the other component is in a proportion of 8 to 15 mol% based on the total acid component of the polyester. These components (third component) are copolymerized. The copolymer component (third component) preferably used is isophthalic acid, phthalic acid, adipic acid, sebacic acid, tetramethylene glycol, trimethylene glycol, diethylene glycol, neopentyl glycol, bisphenol A, 2,2-bis (4 -Hydroxyethoxyphenyl) propane and the like. Among these, what copolymerized 8-15 mol% of isophthalic acid and / or the bisphenol A compound is preferable.

  The filament (B) needs to have an intrinsic viscosity of 0.50 or more, and preferably has an intrinsic viscosity of 0.50 to 0.75. When the filament (B) has an intrinsic viscosity of less than 0.5, the viscosity of the melt at the time of spinning is too low, and it becomes difficult to perform stable spinning. This filament (B) is highly contracted compared to the filament (A) described above.

  The cross-sectional shape of the filament (A) and the filament (B) is not limited to a normal circle, and at least one of the filaments may be non-circular such as flat or trilobal, or may be hollow. Moreover, the single yarn fineness of each of the filament (A) and the filament (B) may be different. These filaments may contain additives such as a stabilizer, an antistatic agent, a matting agent, and a colorant as necessary.

  The blended yarn of the present invention comprising the filament (A) and the filament (B) has an average single yarn fineness of 3 dtex or less, and a ratio based on the total weight of the blended yarn of the filament (B) is 30. It needs to be in the range of not less than 60% by weight and not more than 60% by weight, preferably in the range of not less than 40% by weight and not more than 50% by weight. That is, the blend ratio (weight ratio) of filament (A) / filament (B) in the blended yarn of the present invention is 70/40 to 40/60, preferably 60/40 to 50/50. When the proportion of the filament (B) exceeds 60% by weight, the proportion of the filament (A) is lowered, so the strength as a mixed yarn is lowered. Conversely, when it is less than 30% by weight, the first yield point is obtained. The strength of the secondary yield point becomes low and the object of the present invention cannot be achieved.

  Further, the single yarn fineness of the filament (A) and the filament (B) is preferably 3 dtex or less, particularly preferably 1.0 to 2.8 dtex. This is because when the single yarn fineness exceeds 3 dtex, the yarn becomes stiff and not only difficult to process with twisted yarn, weaving, etc., but also the finished final product is hard and low. However, the single yarn fineness of the filament (A) and the filament (B) is not necessarily the same, and can be arbitrarily selected within the above range.

  In the mixed yarn of the present invention, the filament (A) and the filament (B) are uniformly mixed and entangled with each other to form one yarn. The total fineness of the mixed yarn is appropriately 50 to 100 dtex. The yarn may be crimped as necessary.

  The mixed fiber of the present invention described above can be easily manufactured by the following method, for example. That is, the polyester polymer that forms the filament (A) and the copolyester polymer that forms the filament (B) are heated and melted, and each polymer stream is weighed and sent to the spinning pack. From different spinnerets 7 provided in the same spin pack 6 as illustrated, melt discharge is preferably performed at the same temperature as that of the high intrinsic viscosity polyester.

  In the apparatus in FIG. 2, the melt of the polyester polymer forming the filament (A) and the filament (B) is metered by the core side polymer metering gear pump 3 and the sheath side polymer metering gear pump 4, respectively, in one polymer supply block. 5 is supplied to the spinning pack 6 and discharged from the spinnerets 7 arranged side by side.

  At this time, the melting / liquid feeding temperature of the polymer forming the filament (A) composed of the high intrinsic viscosity component is preferably 290 ° C. or higher and lower than 300 ° C. If the temperature at this time is less than 290 ° C., it is difficult to stably melt and feed the polymer having a high melt viscosity. Above 300 ° C., the deterioration of the polymer is promoted, and the yarn breaks frequently due to the deteriorated product. Cause. On the other hand, the polymer forming the highly shrinkable filament (B) has a melting point / viscosity lower than that of the polymer of the filament (A), and therefore the melting / feeding temperature is 280 ° C. to 290 ° C. for the same reason.

  The melted and discharged yarn is focused after cooling and solidifying by blowing cooling air, and then passing through a fluid processing device such as an interlace nozzle to give entanglement between filaments, preferably 500 to 2500 m / min, preferably Take up at a speed of 800-1500 m / min. At this time, the intrinsic viscosity of the polyester to be used is such that the intrinsic viscosity of the finally obtained filament (A) and filament (B) is in the above range. In addition, a fluid processing apparatus (for example, a nozzle structure) or a fluid processing condition (for example, air pressure) is appropriately selected and set so that the number of entanglements between yarn fibers is 3 to 10 / m.

  In the above example, the case where the filament (A) and the filament (B) are efficiently produced by the spinning blending method in which the filament is simultaneously spun and blended by the same spinning device has been described. The mixed yarn can be manufactured by drawing and entanglement treatment.

  The undrawn yarn subjected to the entanglement treatment is a temperature of 70 to 100 ° C., preferably 80 to 95 ° C., 2.5 to 4.5 times, so as to be a mixed yarn satisfying the above properties by a conventionally known method. Preferably, after stretching at 3.0 to 4.0 times, heat setting is performed at a temperature of 180 to 220 ° C. while giving a relaxation of 3 to 8%. The mixed yarn thus obtained becomes a yarn in which the filament (A) is entangled in a loop around the highly shrinkable filament (B), and when the stress-strain curve (load-elongation curve) is measured, the loop stretches. Until then, the physical properties of the filament (B) are expressed and the shock absorbing performance is expressed. After the loop disappears at the second yield point elongation, the physical properties of the filament (A) are expressed and high breaking durability characteristics. It will be shown.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited by these.

[Example 1]
Polyethylene terephthalate A having an intrinsic viscosity of 0.95 was melted at 295 ° C., and polyethylene terephthalate B copolymerized with 15 mol% of isophthalic acid having an intrinsic viscosity of 0.64 was melted at 285 ° C., respectively. Using equipment capable of spinning, each was melted in an extruder at the temperature shown in Table 1, and then the melt was supplied to the spinning pack. At that time, after the measurement was performed so that the discharge weight ratio on the high intrinsic viscosity side: low intrinsic viscosity side was 5: 5 and the total fineness after drawing was 78 dtex, the temperature was 295 ° C. by the spinning device shown in FIG. From the spinneret. The discharged yarn was entangled with an interlace nozzle after cooling so that the number of entanglement was 10 / m and wound at a speed of 1000 m / min.

  The obtained undrawn yarn was drawn 3.5 times at a temperature of 95 ° C., and then heat-set while being relaxed by 5% at a temperature of 180 ° C. to obtain mixed fiber yarns shown in Table 1. Table 1 shows the evaluation results of the obtained mixed yarn. The single yarn physical properties of the filament (A) and the filament (B) constituting the mixed yarn were measured by separating 20 filaments from each other. The intrinsic viscosity was measured at a temperature of 35 ° C. using o-chlorophenol as a solvent.

When the obtained mixed yarn was subjected to a tensile test in accordance with JIS L-1013 to obtain a load-elongation curve, it was as shown in FIG.
And the seat belt for motor vehicles was produced using the obtained mixed fiber, and the performance was evaluated. The results are shown in Table 1. In addition, the seat belt is generally indicated as “good”, “good” as “good”, and “bad” as “poor”.

[Comparative Example 1]
In Example 1, the same procedure as in Example 1 was conducted except that the relaxation rate at the time of heat setting after drawing was 2%, and the secondary yield point elongation was 2%, which was almost the same as that of a normal high strength yarn. There was no difference. In addition, Table 2 shows the evaluation results of the obtained mixed yarn.

  The polyester blended yarn of the present invention has high strength and excellent shock absorption, and in particular, a safety belt, a safety net, an automobile seat belt, etc. used when performing high-place work such as construction work and electrical work. Therefore, it can be effectively used in these fields.

It is a stress-strain curve of the mixed yarn by Example 1 which shows one embodiment of this invention. It is the schematic of the melt spinning equipment which shows one embodiment of this invention.

Explanation of symbols

1 Primary yield point 2 Secondary yield point 3 Core side polymer metering gear pump 4 Sheath side polymer metering gear pump 5 Polymer supply block 6 Spin pack 7 Spinneret

Claims (3)

A polyester blended yarn comprising at least two types of polyester filaments, and the physical properties of the blended yarn satisfy the following (a) to (d) at the same time.
(A) Strength 4.0 cN / dtex or more (b) Elongation 30% or more (c) Secondary yield point elongation 5-10%
(D) Strength from the first yield point to the second yield point 0.5 to 1.0 cN / dtex   Intrinsic viscosity obtained by copolymerizing polyester filament (A) 40 to 70% by weight with an intrinsic viscosity of 0.75 to 1.00 and a strength of 5.5 cN / dtex or more, and 8 to 15 mol% of isophthalic acid and / or bisphenol A compound. 2. The polyester blend yarn according to claim 1, comprising 60 to 30% by weight of a highly shrinkable polyester filament (B) made of a copolyester of 0.5 or more.   The polyester mixed yarn according to claim 1 or 2, wherein the average single yarn fineness of the polyester filament (A) and the polyester filament (B) is 3 dtex or less, respectively.

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