JP2010090504A - Polyester fiber and fibrous product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fiber and fibrous product suitable for an industrial, especially safety related product, by solving problems of conventional technologies, while reducing an impact received by a human body, etc., absorbing a large energy and having a thermal dimensional stability. <P>SOLUTION: (1) The polyester fiber consisting mainly of an ethylene terephthalate as a recurring unit is provided by having 1.5-2.5 cN/dtex breaking strength (Tb), 150 to 220% breaking elongation (Eb), 1-7% dry heat shrinkage (ΔS), and 1.0×10<SP>-4</SP>to 1.0×10<SP>-2</SP>cN/dtex gradient of secondary standing up stress. (2) The polyester fiber described in the (1), has 40-80% constant stress extension region in the load-extension curve of the polyester fiber. (3) The most preferable form is a fibrous product selected from the group consisting of a safety band, a safety net, a safety belt, a drop-preventing rope, an impact resistant net and an impact-absorbing net by using at least a part of the polyester fiber described in the (1) and (2). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polyester fiber. Specifically, it can be used for industrial materials that combine high elongation, low shrinkage, and high quality, especially in safety-related fields such as safety belts and safety belts, and at low cost without the need for special equipment and facilities. It is related with the polyester fiber which can be.

  Since the fiber which consists of polyester which has ethylene terephthalate as a main repeating unit has various outstanding characteristics, it is widely used not only for the clothing use but for the industrial use. When polyester fibers are used in industrial materials, particularly in safety-related fields such as safety belts and safety belts, a property that is generally regarded as important is that the textiles do not break due to impact during impact or drop. Furthermore, it is required that the stress (impact level) applied to the human body at the time of collision or dropping is small. Further, depending on the application, heat may be applied when the product is processed into a product or used after being processed into a product. In such a case, in order to thermally stabilize the dimensions of the polyester fiber (thermal dimensional stability), it is further required that the shrinkage rate during heating (dry heat shrinkage rate) is small. In order to satisfy such performance, several proposals have been made for fibers used in safety-related fields.

  For example, Patent Document 1 discloses that a polyethylene terephthalate is copolymerized with a bifunctional carboxylic acid such as isophthalic acid or adipic acid or a diol such as neopentyl glycol as a third component, so that the fiber after stretching can be easily contracted. And a method of obtaining a polyester fiber having a higher elongation by performing a relaxation treatment after stretching exceeding 20%, and generally, an elongation-strength curve as shown in FIG. (SS curve). When the fiber absorbs energy while extending as shown in FIG. 1 of Patent Document 1, the energy absorption amount absorbed by the extension of the fiber is surrounded by the SS curve and the elongation axis as shown in FIG. 1 of the present invention. The degree of impact applied to the human body or the like corresponds to the stress in the elongation after energy absorption is completed. Therefore, in the fiber as shown in FIG. 1 of Patent Document 1, since it is stretched with a low stress at the initial stage of elongation, if the load is such that energy absorption is completed in this region, the impact on the human body or the like is small but large. When a load is applied, there is a problem that the degree of impact on the human body or the like is large because the stress extends to a region where the stress suddenly rises.

  Moreover, in order to solve the problem of patent document 1, the method of obtaining the energy absorption polyester fiber which can absorb a big energy with a small impact is disclosed by patent document 2. FIG. This technique relates to a polyester fiber characterized in that the yield point stress (Ty) and the breaking strength (Tb) are Tb / Ty ≦ 1.4, and the polyester fiber has a constant yield point stress and a breaking elongation. Since the difference is small, it is possible to absorb the impact while stretching with a constant stress and reduce the load applied to the human body or the like. However, further improvement has been demanded as an energy-absorbing polyester fiber capable of absorbing large energy with a small impact.

  Patent Document 3 discloses a technique for obtaining a safety belt excellent in both initial restraining force and impact absorption by combining high-elasticity yarns and general-purpose fibers such as polyethylene terephthalate. However, since high-cost fibers such as polyarylate fibers and aramid fibers, which are generally expensive and poor in dyeability, are used, the resulting fiber product has a problem that it is expensive and dyeing spots are likely to occur. . In addition, when using multiple types of fibers, the design is not only poor in handling at the time of manufacture, but also has a non-uniform woven structure due to differences in the thermal shrinkage rate inherent to the fibers in the dyeing and heat setting processes. It also has problems.

Patent Document 4 discloses a method for obtaining a composite yarn obtained by combining a relaxation heat-treated yarn of polyester multifilament undrawn yarn having self-extension ability and polyester multifilament drawn yarn. However, the composite yarn fibers disclosed in Patent Document 4 are not only poor in handling at the time of production, but also have a poor woven structure due to differences in the thermal contraction rate inherent to the fibers in the dyeing and heat setting processes. It also has the problem that it becomes uniform and the breaking strength decreases. In addition, the thermal dimensional stability is poor due to the self-extension ability, and there is a problem that the shape retention is remarkably insufficient when used for textile products such as safety belts and safety nets. As described above, while technological development related to fibers and textile products that absorbs large energy and is thermally stable while reducing the impact (stress) received by the human body, etc., all of them are satisfied at the same time. At present, fibers and fiber products are not obtained.
JP-A-9-143816 JP 2003-64526 A JP-A-8-72668 JP-A-8-158183

  The present invention is a fiber and fiber product suitable for industrial use, particularly safety-related products, which solves the problems of the prior art, absorbs large energy while reducing the impact received by the human body, etc., and stabilizes thermal dimensions. It is an object to provide a fiber and a fiber product having properties.

As a result of diligent investigation in view of such conventional technology, the present inventors have absorbed a large amount of energy while reducing the load received by the human body etc., while the polyester fiber having the following characteristics and the fiber product using the polyester fiber have the following characteristics: The present inventors have found that the thermal dimensional stability is excellent and have reached the present invention. That is, the present invention
(1) A fiber made of polyester having ethylene terephthalate as a main repeating unit, having a breaking strength (Tb) of 1.5 to 2.5 cN / dtex, a breaking elongation (Eb) of 150 to 220%, and dry heat shrinkage A polyester fiber having a rate (ΔS) of 1 to 7% and a slope of secondary rising stress of 1.0 × 10 ^{−4 to} 1.0 × 10 ⁻² cN / dtex ·%, (2) elongation of the polyester fiber A safety band comprising at least a portion of the polyester fiber according to (1), the polyester fiber according to (3) (1) or (2), wherein the constant stress elongation region in the strength curve is 40 to 80%, It is a textile product that is one selected from the group consisting of a safety net, a safety belt, a fall prevention rope, an impact resistant net, and an impact absorbing net.

  The polyester fiber of the present invention has a yield point stress that reduces the impact applied to the human body and the like, and after stretching at a constant stress, enables large energy absorption while gradually raising the stress. Furthermore, since the thermal shrinkage rate is low, the thermal dimensional stability is excellent, and there is no change in physical properties over time. The textile product of the present invention can be suitably used as a safety material that protects the human body and the like from impact in the event of a collision, dropping, or the like.

  The polyester fiber of the present invention has a breaking strength (Tb) of 1.5 to 2.5 cN / dtex, preferably 1.7 to 2.4 cN / dtex, more preferably 1.8 to 2.3 cN / dtex. is there. If the breaking strength exceeds 2.5 cN / dtex, the stress rise (secondary rise stress) after elongation after yielding in the SS curve becomes abrupt, so there is a concern that a sudden load is applied to the human body or the like at the time of impact. is there. When the breaking strength is less than 1.5 cN / dtex, there is a concern that the fiber breaks before absorbing the amount of energy necessary for impact. Further, when the amount of fibers used in the fiber product is increased in order to prevent fiber breakage, there is a problem that the weight of the product is large and the handleability is inferior.

  The polyester fiber of the present invention has a breaking elongation (Eb) of 150 to 220%, preferably 170 to 215%, and more preferably 180 to 210%. When the elongation at break exceeds 220%, the yield stress of the SS curve is low, and the area surrounded by the SS curve, which is the amount of energy absorption, and the elongation axis becomes small. Sufficient energy absorption is not performed, and it is necessary to extend to a region where stress rises. As a result, the degree of impact on a human body or the like increases. When the elongation at break is less than 150%, the yield stress of the SS curve is high, and the load on the human body or the like at the moment of impact is increased. In addition, since the slope of the secondary rising stress increases, there is a concern that a sudden load is applied to the human body or the like at the time of a large impact. The yield stress referred to in the present invention refers to the stress at the point of yielding after the initial rise of the SS curve as shown in FIG.

  Furthermore, the polyester fiber of the present invention has a dry heat shrinkage (ΔS) of 1 to 7%, preferably 1 to 6.5%, more preferably 1 to 6%. The polyester fiber of the present invention may be subjected to a tension heat setting treatment at the time of dyeing or knitting, or may be exposed for a long time in a high temperature atmosphere such as outdoors under a hot sun. The fiber having the dry heat shrinkage rate of the present invention satisfying the above range has no fiber elongation or large shrinkage when exposed to a high temperature atmosphere at the time of dyeing or tension heat setting, and the quality of the fiber product is high. You can get a good product. When the dry heat shrinkage rate is 0 or more and less than 1%, there is a problem that when the fiber product such as a net is used, the mesh is not sufficiently fixed, the mesh is displaced, and the strength of the knitting itself is further reduced. If it is less than 0%, there is a problem that the thermal dimensional stability is poor due to the self-extension ability in a high temperature atmosphere such as outdoors under a hot sun, and the shape retention is remarkably insufficient. When the dry heat shrinkage rate exceeds 7%, when a fiber product is formed, the heat treatment will cause the fiber product to shrink greatly due to the shrinkage of the fiber, increasing the thickness, resulting in poor storage and light weight. There is a problem.

In the polyester fiber of the present invention, the slope of the secondary rising stress is 1.0 × 10 ^{−4 to} 1.0 × 10 ⁻² cN / dtex ·%, preferably 3.0 × 10 ^{−4 to} 7.5. It is * 10 < ^-3 > cN / dtex *%, More preferably, it is 5.0 * 10 < ^-4 > -5.0 * 10 < ^-3 > cN / dtex *%. Here, the slope of the secondary rising stress is the point at which constant stress is extended after yielding in the SS curve shown in FIG. 1 and thereafter the stress rises (the initial point where the stress becomes constant after yielding shown in FIG. The initial point where the slope of the straight line when connecting to any point on the SS curve is 1.0 × 10 ⁻⁴ cN / dtex ·% or more) It refers to the slope of the tangent line of the SS curve connected at the point where the degree increases. The constant stress elongation region of the present invention means that the slope of a straight line when connecting an initial point where the stress becomes constant after yielding and an arbitrary point on the SS curve in the SS curve shown in FIG. It refers to the elongation of a region smaller than 0 × 10 ⁻⁴ cN / dtex ·%. When the slope of the secondary rising stress is large, it indicates that a load is applied suddenly to the human body, etc. at the time of impact such as dropping, and when the slope of the secondary rising stress is small, the impact does not rise suddenly. It means to absorb. When the slope of the secondary rising stress is less than 1.0 × 10 ⁻⁴ cN / dtex ·%, the stress after yielding does not rise, so that the stress received by the fiber is not propagated when receiving an impact. The stress is concentrated at one point, and there is a concern that the fiber breaks before the impact absorbing ability is exhibited. When the slope of the secondary rising stress exceeds 1.0 × 10 ⁻² cN / dtex ·%, since the stress rises rapidly, there is a concern that a sudden load is applied to the human body or the like at the time of impact.

  In the polyester fiber of the present invention, the constant stress elongation region in the SS curve is preferably 40 to 80%, more preferably 45 to 80%, and still more preferably 50 to 80%. When the constant stress elongation region satisfies the range of 40 to 80%, the energy is absorbed and absorbed at a constant stress until the stress rises after yielding. Since energy absorption can be completed, a large load is not applied to the human body. Further, it is preferable that the SS curve gradually rises after the constant stress elongation region, so that the stress is concentrated at one point and the impact absorbing ability is exhibited without breaking the fiber or the fiber product.

  In this invention, the fiber which consists of polyester which has ethylene terephthalate as a main repeating unit refers to the thing which the repeating unit of ethylene terephthalate is 98 mol% or more, More preferably, it is 100 mol%. The polyester fibers used in the present invention are matting agents such as titanium oxide, calcium carbonate, kaolin, clay, pigments, dyes, lubricants, antioxidants, heat resistance agents, heat resistance agents, light resistance agents, ultraviolet absorbers, antistatic agents. And flame retardants and the like.

  In the polyester fiber of the present invention, the single fiber fineness and the total fineness are not particularly limited, but the single fiber fineness is preferably 2 to 25 dtex, and the total fineness is preferably 500 to 3000 dtex. When the single fiber fineness satisfies the above range, it is advantageous in wear resistance, and it is preferable because cooling can be performed uniformly in the cooling step after spinning. When the total fineness satisfies the above-mentioned range, it is preferable because the productivity per unit time can be produced efficiently and efficiently, and industrially advantageous production becomes possible. The cross-sectional shape of the polyester fiber of the present invention is not particularly determined, and fibers having various cross-sections such as a flat cross-section, a hollow cross-section, and a core-sheath composite cross-section are used for the purpose of thinning, improving rigidity, and improving design. can do.

  Next, an example of a method for obtaining the polyester fiber of the present invention will be shown taking polyethylene terephthalate melt spinning as an example, but the present invention is not limited to this, and other known spinning methods can be adopted. The intrinsic viscosity (IV) of the polyester used in the present invention is preferably in a specific range from the viewpoint of controlling the breaking strength and elongation. In the case of polyethylene terephthalate, the intrinsic viscosity is in the range of 0.8 to 1.3. Preferably, it is 0.9-1.2. It can be obtained by melting and kneading a polyethylene terephthalate resin chip having an ethylene terephthalate repeating unit of 98 mol% or more filled in a hopper in a nitrogen atmosphere into an spinning pack and discharging from a spinneret. . When adding the aforementioned additives, etc., there are a method of directly mixing with an extruder, or a method of preparing a polyethylene terephthalate resin master chip containing a high concentration of additives in advance and blending the chips before melting. Can be adopted.

  The melt spinning temperature can be appropriately changed depending on the intrinsic viscosity, polymer type, and the like, but is preferably 270 to 320 ° C. When spinning at less than 270 ° C., there is a possibility that sufficient fluidity cannot be obtained when the polymer is melted. At temperatures exceeding 320 ° C., the polymer is decomposed and polyester fibers as in the present invention cannot be obtained. There is sex. Immediately below the spinneret, the upper end is 0 to 15 cm from the spinneret surface, the range from 5 to 30 cm from the upper end is surrounded by a heating cylinder and / or a heat insulating cylinder, and the spinning yarn is placed in a high-temperature atmosphere at 250 to 350 ° C. By passing it in a short time, an undrawn yarn with a low degree of amorphous part orientation can be obtained. The above conditions are preferred because a high degree of orientation in the amorphous part results in low elongation and a sudden rise in secondary stress, making it difficult to obtain the properties of the present invention.

  The unstretched yarn that has passed through the high-temperature atmosphere is then preferably cooled and solidified by blowing air of 10 to 100 ° C., preferably 15 to 75 ° C. When the cooling air is less than 10 ° C., a large cooling device is required separately from the normal device, which is not preferable. In addition, when the cooling air exceeds 100 ° C., the single fiber sway during spinning becomes large, so that the single fibers collide with each other, making it difficult to produce the fibers with good spinning properties. The air cooling device may be a horizontal blowing type (uniflow type) or an annular blowing type. Moreover, when a high cooling effect is required like a monofilament, a cooling method such as water cooling can be adopted.

  The unstretched yarn that has been cooled and solidified is then applied with an oil agent by an oil supply device. The oil agent may be aqueous or non-aqueous. It is preferable to have an oil composition containing a smoothing agent as a main component, including a surfactant, an antistatic agent, an extreme pressure agent component, and the like, and excluding components active in a polyester resin. For example, an alkyl ether ester as a smoothing agent component, an alkylene oxide adduct of a higher alcohol as a surfactant component, and a non-aqueous oil agent in which an organic phosphate salt or the like is diluted with mineral oil as an extreme pressure agent component is more preferable.

  The unstretched yarn to which the oil agent is applied is wound around a take-up roller. The surface speed of the take-up roller, that is, the take-up speed is preferably 1000 to 2500 m / min, more preferably 1300 to 2300 m / min. When the take-off speed is less than 1000 m / min, the yield stress of the SS curve is low, the amount of energy that can be absorbed in the constant stress extension region is small, sufficient energy absorption is not performed, and it is necessary to extend to a region where the stress rises. As a result, the stress applied to the human body or the like increases. When the take-up speed exceeds 2500 m / min, the yield stress increases in the SS curve, and the load applied to the human body and the like at the time of impact absorption increases. Moreover, it becomes difficult to obtain a fiber having a breaking elongation of 150 to 220% as in the present invention.

The undrawn yarn taken up at the take-up speed is preferably heat-treated at a draw ratio of 1 to 1.35 times, more preferably 1 to 1 after being wound up or continuously without being wound up. .3 times, more preferably 1 to 1.25 times. When the draw ratio exceeds 1.35 times, since the slope of the secondary rising stress after the constant stress elongation region becomes steep, the slope of the secondary rising stress as in the present invention is 1.0 × 10 ^−4. It is difficult to obtain a polyester fiber of ˜1.0 × 10 ⁻² cN / dtex ·%, and when it is made into a fiber product, there is a concern that a sudden load is applied to a human body or the like when an impact that requires a large amount of energy absorption is applied. There is.

  For example, as a drawing method, similarly to a take-up roller (hereinafter sometimes abbreviated as 1FR), a Nelson type roller having two rollers as one unit is a yarn feeding roller (hereinafter sometimes abbreviated as 2FR), Arranged side by side with a first stretching roller (hereinafter abbreviated as 1DR), a heat setting roller (hereinafter abbreviated as 2DR) and a relaxation roller (hereinafter abbreviated as RR). The film is wound and subjected to the stretching heat treatment under the above conditions. At this time, the number of stretching stages, the number of rollers, and the stretching ratio between the rollers are not particularly limited. Usually, stretching is performed between the take-up roller and the yarn supply roller in order to converge the yarn. The stretch rate is preferably in the range of 1 to 5%. The take-up roller is heated to 50 to 90 ° C. to preheat the take-up yarn and sent to the next drawing step.

  Stretching is performed between a yarn feeding roller and a heat setting roller. The temperature of the yarn feeding roller is set to 70 to 120 ° C., and then the yarn is stretched at 90 to 98% of the stretching ratio by the first stretching roller (100 to 140 ° C.). And heat setting is performed while the yarn is stretched at 1 to 5% of the total draw ratio with a heat setting roller. The reason why the yarn is stretched at 90 to 98% of the stretching ratio with the first stretching roller is to perform stretching in a fluid state where the molecules are not crystallized, to further enhance the stretching effect and advance the orientation. is there. The stretched yarn is heat-set at 130 to 170 ° C. with a heat setting roller, and then 0 to 7%, preferably 0 to 5%, more preferably 0 to 0 between the heat setting roller and the relaxation roller. 3% relaxation treatment is carried out and wound up by a winder. In the relaxation treatment, not only the strain caused by thermal stretching can be removed, but also the structure achieved by stretching can be fixed, the orientation of the amorphous region can be relaxed, and the thermal shrinkage rate can be lowered. As the relaxation roller, a non-heated roller or a roller heated to 150 ° C. or less is used. When the above conditions are satisfied, it is considered that a fiber structure that satisfies the characteristics of the present invention is formed.

  Conventionally, when a spun undrawn yarn is taken up at a speed of 2500 m / min or less, drawn at a draw ratio of 1-1.35 times, and heat above the crystallization temperature is suddenly applied by a heat setting roller, When the glass transition temperature (about 70 ° C.) is greatly exceeded, the molecular motion becomes extremely active, and there is a problem that the yarn swaying is large and the spinning property is deteriorated. In the present invention, in order to solve the above problems, undrawn yarn spun as in the present invention is taken up at a take-up speed of 1000 to 2500 m / min, molecular chains are aligned and oriented, and heat set from a yarn feeding roller. It is preferable to apply heat at a crystal start temperature of 100 to 120 ° C. until the roller, more preferably at 110 ° C. to 120 ° C., and heat near the crystal start temperature is gradually increased for a long time (0.2 to 0.3 seconds). (Preferably, 0.22 to 0.28 seconds) and slowly crystallize, and by not performing high-temperature heat setting exceeding 170 ° C. It became possible to complete the process and to produce the yarn without shaking. However, when the heat set temperature is less than 130 ° C., the crystallization does not proceed sufficiently, and relaxation of heat shrinkage cannot be obtained. Therefore, the fiber having a dry heat shrinkage rate (ΔS) of 1 to 7% as in the present invention. It becomes difficult to obtain. The crystallization onset temperature of the present invention refers to the temperature at which the crystallization exotherm begins in the DSC curve.

  In addition, in order to obtain high-quality polyester fibers with less generation of fluff, high-pressure fluid is sprayed on the fiber yarns between the yarn feeding roller and the first drawing roller, and the yarns constituting the fibers are entangled. And may be stretched while converging the yarn. The entanglement imparting device for entanglement and convergence of the yarn can use an entanglement nozzle that is usually used to impart and entangle the yarn just before winding the yarn. The entanglement imparting device is effective when it is stretched in the first stage, but it may also be performed when stretching the second and third stages in addition to the first stage. The entanglement degree (CF value) applied to the polyester fiber is preferably 5 to 70, more preferably 10 to 60. When the degree of entanglement is less than 5, it is not preferable because process passability in high-order processing is deteriorated. If the degree of entanglement is greater than 70, loops are likely to occur, making it difficult to perform high-order processing stably.

  The polyester fiber according to the present invention is characterized in that the range of 5 to 30 cm is surrounded by a heating cylinder and / or a heat insulating cylinder, the polyester fiber is rapidly cooled and solidified, and molecular chains are aligned and oriented at a take-up speed of 1000 to 2500 m / min. It is obtained by stretching at a low magnification of 1 to 1.35 times, applying heat in the vicinity of the crystal start temperature (100 to 120 ° C.) stepwise and for a long time, and further combining heat at a low temperature of 130 to 170 ° C. Can do.

  The textile product of the present invention uses at least a part of the polyester fiber of the present invention. By using the polyester fiber of the present invention, it has excellent shock absorption capacity, reduces the load on the human body, etc., and has a safety belt, safety net, safety belt, fall prevention rope, impact resistance net, excellent thermal dimensional stability, It is possible to obtain a textile product suitable for safety use such as an impact absorbing net.

  Next, the production method of the textile product of the present invention will be described by taking a safety belt as an example. However, the production method of the textile product of the present invention is not limited to this, and a generally known net, belt, rope, woven or knitted fabric is used. A manufacturing method such as the above can be adopted. The polyester fiber manufactured as described above is woven using a needle loom under the following conditions. For example, a synthetic fiber multifilament made of ordinary circular cross-section yarn is used as the weft, and the polyester fiber of the present invention having a fineness of 1100 dtex and 200 single fibers is used as the warp webbing. The weave density is not limited and can be changed according to the required energy absorption characteristics. In addition, there is no particular rule on the weaving structure at this time, and plain weaving, oblique weaving, satin weaving or a combination weaving structure can be adopted, but in order to increase the initial stress of webbing, weave or satin weaving Is preferably adopted. The thickness of the webbing is not particularly specified, but is preferably in the range of 2.0 to 3.0 mm. When the webbing thickness exceeds 3.0 mm, there is a problem that the storage property is inferior. When the webbing thickness is less than 2.0 mm, there is a concern that the webbing may be broken when an impact is applied to the webbing. is doing.

  The webbing may be dyed as necessary. For the dyeing, a normal dyeing method may be employed. For example, a method of treating at 170 ° C. for 1 minute after immersion in a dyeing bath can be used. As the dye, usual polyester dyes such as anthraquinone dye, azo dye, nitrodienylamine dye, methine dye and naphthoquinone dye can be used. In general, a desired color can be obtained by combining red, blue and yellow dyes. Further, when dyeing, within a range that does not impair the effects of the present invention, dispersion / level dyeing represented by ethoxylated dioctylphenol, anionic nonionic surfactant, alkyl alcohol polyglycol ether, sulfate ester salt, etc. In addition to the agent and the wetting agent, additives such as an anti-migratory agent, a pH adjuster, an ultraviolet absorber and an antioxidant may be added to the dye solution.

  The obtained webbing of the present invention can be used for, for example, a safety belt composed only of the polyester fiber of the present invention as shown in FIG. 3 and a shock absorber type safety belt as shown in FIGS. The usage is not limited to this. The shock absorber referred to in the present invention refers to a device for mitigating the impact that occurs when preventing a crash, and the webbing of the present invention is used for the short part as shown in FIG. What is comprised by the high strength synthetic fiber multifilament webbing which consists of a thread | yarn is mentioned. In the shock absorber type safety belt as shown in FIG. 4, the polyester fiber of the present invention used for the short portion starts to stretch and absorbs the impact gradually, and the long portion suppresses the breakage of the safety belt. With this configuration, at the beginning of the extension of the short part, the constant stress extension region of the polyester fiber of the present invention absorbs a large amount of energy with a small impact on the human body and the like, while reducing the load on the human body etc. When it is fully stretched, the impact absorbing ability of the long part is developed, and the safety belt can be prevented from breaking. Moreover, the thing using the polyester fiber of this invention for the warp as shown in FIG. 5, and using the high strength synthetic fiber multifilament as the entanglement warp (refer FIG. 5) is also mentioned. When an impact is applied to the safety belt, the tangled warp is stretched as the belt is stretched, and when the tangled warp is fully stretched, the impact absorbing ability is exhibited, and the safety belt can be prevented from breaking. Thus, the polyester fiber product of the present invention can be obtained.

Hereinafter, embodiments of the present invention will be described in more detail by way of examples. The property definitions and measurement methods are as follows.
[Total Fineness]: JIS L1013 (1999) 8.3.1a) Based on A method, using a measuring machine manufactured by Nakayama Electric Industry Co., Ltd. and applying an initial load of display fineness x 0.45 mN / dtex. And the total fineness.

[Single fiber fineness]
The total fineness was calculated by dividing by the number of single fibers. Here, the number of single fibers was calculated according to JIS L1013 (1999) 8.4.

[Elongation at break (Eb), strength at break (Tb), yield stress, constant stress elongation range, slope of secondary rising stress]
Using a “Tensilon” tensile tester manufactured by Orientec Co., Ltd., the SS curve (elongation-strength property) obtained under the conditions of a sample length of 10 cm and a tensile speed of 30 cm / min is obtained. As shown in FIG. 1, the stress at the yield point after the initial rise of the SS curve was defined as the yield stress. In the SS curve, the slope of the straight line when connecting an initial point where the stress is constant after yielding and an arbitrary point on the SS curve is smaller than 1.0 × 10 ⁻⁴ cN / dtex ·%. The elongation of the region was defined as a constant stress elongation region, and the slope of the stress after the constant stress elongation was defined as the slope of the secondary rising stress.

[Dry heat shrinkage (ΔS)]
According to JIS L1013, heat treatment was performed for 30 minutes under no load in a dry heat furnace at 150 ° C., and the test length before and after the heat treatment test was measured under a load of 0.10 cN / dtex, and was determined according to the following formula. The measurement was performed twice to obtain an average value.
Dry heat shrinkage (%) = (Test length before treatment−Test length after treatment) × 100 / Test length before treatment [Intrinsic viscosity (IV)]
The relative viscosity η of a solution in which 8 g of the sample was dissolved in 100 mL of orthochlorophenol was measured at 25 ° C. using an Ostwald viscometer, and obtained by an approximate expression of IV = 0.0242η + 0.2634.

[Degree of confounding (CF value)]
A 100 g load is applied to a sample of 1 m length, a 6 g hook is lowered at a descending speed of 1 to 2 cm / sec, and calculated by the formula: Entanglement (CF value) = 100 (cm) / Descent distance (cm) Asked. An average value of 10 trials was adopted.

[Evaluation of safety band consisting only of polyester fiber of the present invention]
As a safety belt as shown in FIG. 3, the polyester fiber of the present invention is used to test a belt test length of 200 cm (weaving polyester base yarn 560-96-702C manufactured by Toray Industries Inc. at a weaving density of 20 yarns / inch, The polyester fiber of the present invention having a fineness of 1100 dtex and 120 single fibers was driven at a weaving density of 100 fibers / inch to make a webbing of 51 mm width), and 85 kg of sandbags were used. A load drop test is performed based on the impact resistance of the safety belt standard (2002) Article 7 established based on the provisions of Article 42, and the impact energy of the drop is calculated from the area surrounded by the SS curve, The stress applied to the human body was determined. In the above test, the load energy (J (= N · m)) applied to the belt is 85 kg × 9.81 m / s ² × 2 m = 1667.7 N · m, and the SS curve and the elongation axis of the belt Since this corresponds to the area surrounded by, the stress in the elongation at the time when the energy absorption is completed is an impact applied to the human body.

[Shock absorber type safety belt evaluation]
As a shock absorber type safety belt as shown in FIG. 4, the polyester fiber of the present invention is used for the short length portion of the belt, the belt test length is 200 cm (the polyester yarn 560-96-702C manufactured by Toray Industries, Ltd. is used for the weft, and the weaving density is 20 pieces. For the warp, the polyester fiber of the present invention having a fineness of 1100 dtex and a single fiber number of 120 is driven at a weaving density of 100 fibers / inch to make a webbing with a width of 51 mm). Using a yarn 1100-240-704D, a belt test length of 300 cm (polyester yarn 560-96-702C manufactured by Toray Industries, Inc. is driven into the weft at a weaving density of 20 / inch, and the warp yarn has 100 polyester fibers of the polyester fiber. / Inch to make a webbing with a width of 51 mm) and labor using an 85 kg sandbag Safety drop standard based on the provisions of Article 42 of the Sanitation Act (2002) Conducts a load drop test based on the impact resistance etc. of Article 7, and the impact energy of the fall is surrounded by an SS curve The stress applied to the human body was calculated from the area. In the above test, the load energy (J (= N · m)) applied to the belt is 85 kg × 9.81 m / s ² × 2 m = 1667.7 N · m, and the SS curve and the elongation axis of the belt Since this corresponds to the area surrounded by, the stress in the elongation at the time when the energy absorption is completed is an impact applied to the human body.

Example 1
A polyethylene terephthalate polymer having an intrinsic viscosity of 1.23 manufactured by Toray Industries, Inc. was continuously fed to a single screw extruder type extruder at 295 ° C. and continuously melted. The melted polymer is kneaded with an eight-stage static mixer through a pipe at 295 ° C, weighed with a gear pump so that the total fineness becomes 1100 dtex, led to a spin pack at 295 ° C, and passed through a 10-micron cut filter in the pack. Then, extrusion spinning was performed from a die having 120 round single holes each having a hole diameter of 0.6 mm and a hole length of 0.78 mm. After passing through a heated cylinder having a length of 7 cm and an atmospheric temperature of 285 ° C. provided with a spun yarn under the base, cold air of 40 ° C. was blown and solidified at a rate of 30 m / min using an annular chimney, An oil agent (manufactured by Sanyo Chemical Co., Ltd .: Sun Oil F) was applied with an oil agent roll. The yarn provided with the oil was wound up at 1FR (70 ° C.) having a surface speed of 1570 m / min, and then subjected to the stretching step continuously.

  2FR (90 ° C) at a speed of 1600 m / min, 1DR at a speed of 1920 m / min (120 ° C), 2DR at a speed of 2000 m / min (140 ° C), a speed of 2000 m / min without winding the yarn that has passed through 1FR The film was stretched by being continuously subjected to RR (non-heated). The entanglement processing device is installed between 2FR and 1DR (EC-Y23 manufactured by Toray Industries, Inc.) and between RR and the take-up roller (PP3500 manufactured by Heberline), and injects high-pressure air of 0.5 MPa and 0.6 MPa, respectively. Thus, a polyester fiber was obtained. Using the polyester fiber obtained here, a safety belt as shown in FIG. 3 having a belt test length of 200 cm (polyester raw yarn 560-96-702C manufactured by Toray Industries, Inc. is driven into the weft at a weaving density of 20 yarns / inch, Made a polyester web obtained by the above method at a weaving density of 100 fibers / inch to make a webbing with a width of 51 mm). The characteristics of the obtained polyester fiber are shown in Table 1 and FIG. 2, the evaluation results of the obtained safety belt are shown in Table 2, and the stress with respect to belt elongation is shown in FIG.

(Example 2)
Winding at 1FR (70 ° C.) having a surface speed of 1850 m / min, 2FR (90 ° C.) at a speed of 1880 m / min, 1DR at a speed of 1920 m / min (120 ° C.), 2DR at a speed of 2000 m / min (140 ° C. ), Except that it was continuously subjected to RR (non-heated) at a speed of 2000 m / min.

(Example 3)
Winding at 1FR (70 ° C) with a surface speed of 1500m / min, 2FR (90 ° C) at a speed of 1540m / min, 1DR at a speed of 1920m / min (120 ° C), 2DR at a speed of 2000m / min (140 ° C) ), Except that it was continuously subjected to RR (non-heated) at a speed of 2000 m / min.

Example 4
Winding at 1FR (70 ° C.) having a surface speed of 2380 m / min, 2FR (90 ° C.) at a speed of 2400 m / min, 1DR at a speed of 2430 m / min (120 ° C.), 2DR at a speed of 2500 m / min (150 ° C. ), The same as Example 1 except that it was continuously subjected to RR (non-heated) at a speed of 2475 m / min.

(Example 5)
Winding up at 1FR (70 ° C) with a surface speed of 2380 m / min, 2FR at 2400 m / min (90 ° C), 1DR at a speed of 2430 m / min (120 ° C), 2DR at a speed of 2500 m / min (170 ° C) ), The same as in Example 1 except that it was continuously subjected to RR (non-heated) at a speed of 2480 m / min.

(Example 6)
As a shock absorber type safety belt as shown in FIG. 4, the polyester fiber obtained in Example 5 is used for the short portion, the belt test length is 200 cm (polyester yarn 560-96-702C manufactured by Toray Industries, Inc. is used as the weft). The polyester fiber obtained in Example 5 was driven at a weaving density of 100 yarns / inch to form a webbing of 51 mm in width, and a polyester raw material manufactured by Toray Industries, Inc. was used for the long portion. Using a yarn 1100-240-704D, a belt trial length of 300 cm (polyester yarn 560-96-702C manufactured by Toray Industries, Inc. was driven into the weft at a weaving density of 20 / inch, and the warp yarn was filled with 50 of this polyester fiber. This was performed in the same manner as in Example 1, except that a webbing with a width of 51 mm was made by driving in / inch.

(Comparative Example 1)
Using IV 0.68 polyethylene terephthalate polymer, passing the spinning yarn through a heating cylinder with a length of 30 cm and an ambient temperature of 300 ° C. under the base, and using a ring-type chimney to cool air at 18 ° C. It was solidified by spraying at a speed of 30 m / min, wound at 1 FR (70 ° C.) having a surface speed of 4000 m / min, 2FR (120 ° C.) at a speed of 4120 m / min, 1DR at a speed of 5155 m / min (120 ° C. ), 2DR (190 ° C.) at a speed of 5155 m / min, and RR (non-heated) at a speed of 5000 m / min were used in the same manner as in Example 1.

(Comparative Example 2)
The same procedure as in Example 4 was performed except that the 2DR heat setting temperature was 120 ° C.

(Comparative Example 3)
Winding at 1FR (70 ° C.) having a surface speed of 1750 m / min, 2FR (90 ° C.) at a speed of 1770 m / min, 1DR at a speed of 2390 m / min (120 ° C.), 2DR at a speed of 2480 m / min (130 ° C. ), The same as in Example 1 except that it was continuously subjected to RR (non-heated) at a speed of 2480 m / min.

(Comparative Example 4)
It was carried out in the same manner as in Example 1 except that it was wound at 1 FR having a surface speed of 900 m / min, and wound at a constant length without stretching, stretching and heat treatment.

  The fiber products of Comparative Examples 2 and 4 which are not polyester fibers of the present invention have a small dry heat shrinkage ratio, although the stress applied to the human body and the like during impact absorption is small. As a result, the entire fiber product contracts greatly to increase the thickness, resulting in inferior storage properties and light weight. Moreover, when the fiber products of Comparative Example 1 and Comparative Example 3 absorb energy, the stress increases abruptly, and the belt hardly expands and a large load is applied to the human body. On the other hand, the polyester fiber fiber product that satisfies the scope of the present invention can absorb a large amount of energy with low stress by stretching, and a large load is not applied to the human body etc. A product.

  The polyester fiber of the present invention has a yield point stress that reduces the impact on the human body, etc., and is capable of absorbing a large amount of energy while gradually raising the stress after being stretched at a constant stress. It has excellent thermal dimensional stability due to its low shrinkage rate, and it does not change over time, so it is suitable as a safety material that protects the human body from impacts when impacting or dropping when used as a textile product. Can be used for

It is explanatory drawing of the yield stress, the constant stress expansion | extension area | region, the inclination of a secondary rising stress, and energy absorption. It is SS curve of the polyester fiber obtained in Example 5, Comparative Example 1, and Comparative Example 4, respectively. It is a safety belt made only of the polyester fiber of the present invention. It is a safety belt using the polyester fiber of the present invention as a shock absorber. It is a safety belt in which the warp yarn is combined with the safety belt of the polyester fiber of the present invention. It is the figure which showed the stress (kN) with respect to expansion | extension (m) of the safety belt | band | zone obtained in Example 5, Example 6, and the comparative example 1, respectively.

Explanation of symbols

1-1: Yield stress 1-2: Initial point where the stress becomes constant 1-3: Constant stress extension region 1-4: Energy absorption 1-5: Slope of secondary rising stress 3-1: Polyester fiber 3-2: Sewing part 4-1: Short part (polyester fiber of the present invention)
4-2: Sewing part 4-3: Long part (high-strength polyester fiber, etc.)
5-1: Polyester fiber of the present invention 5-2: Sewing part 5-3: Tangle warp

Claims (3)

A fiber made of polyester having ethylene terephthalate as a main repeating unit, having a breaking strength (Tb) of 1.5 to 2.5 cN / dtex, a breaking elongation (Eb) of 150 to 220%, and a dry heat shrinkage (ΔS ) Is 1 to 7%, and the slope of the secondary rising stress is 1.0 × 10 ^{−4 to} 1.0 × 10 ⁻² cN / dtex ·%. 2. The polyester fiber according to claim 1, wherein the constant stress elongation region in the elongation-strength curve of the polyester fiber is 40 to 80%. A fiber which is one selected from the group consisting of a safety belt, a safety net, a safety belt, a fall prevention rope, an impact resistance net and an impact absorption net, comprising at least part of the polyester fiber according to claim 1 or 2. Product.

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