JP2000190810A - Synthetic fiber for seat belt, and seat belt webbing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a synthetic fiber for a seat belt whose rigidity in the latitude direction is improved, and to intend a seat belt to be excellent in the rigidity, in particular the rigidity in the latitude direction and to have stable storing properties and hardly to turn over and to protect the occupants surely from an accident if they should encounter it. SOLUTION: This synthetic fiber is composed of the multi-filament of a single fiber with a triangle or Y shape section. In this case, the deformation degree (H) of the single fiber is 1.5-4.0 and a single fiber fineness (d) is 4-40 denier. In the seat belt webbing, the synthetic fiber for a seat belt is used as a latitude yarn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic fiber for a seat belt and a seat belt webbing, and more particularly, to a synthetic fiber for a seat belt having improved rigidity in a weft direction as compared with a conventional synthetic fiber, and particularly to a weft. The present invention relates to a seat belt webbing that has excellent directional rigidity, has stable storage properties, is unlikely to cause reversal of a seat belt, and can reliably protect an occupant in the event of an accident.

[0002]

2. Description of the Related Art Generally, a three-point seat belt webbing used in a front seat of a passenger car or the like can be smoothly pulled out from a retractor when worn, and can be stored in a retractor naturally when detached. Performance is required.

[0003] As means for satisfying these required performances, slipperiness is improved by reducing the thickness of the seatbelt webbing as much as possible or by subjecting the surface of the seatbelt webbing to resin processing or the like. Methods to improve the storage properties have been studied,
For example, U.S. Pat. No. 4,107,371, JP-A-55-116831 and Japanese Patent Publication No. 4-66984.
It is proposed in Japanese Patent Publication No.

That is, US Pat. No. 4,107,371
The method described in the specification describes that a synthetic resin monofilament is used as the weft constituting the webbing for the seatbelt, and according to this method, the rigidity in the weft direction of the webbing for the seatbelt is improved. As a result, it is possible to suppress the reversal at the time of pulling out or winding up by the slip guide, so that it is possible to obtain the effect of improving the retractability in the retractor. But,
When a monofilament is used as the weft of the seat belt webbing, the rigidity of the monofilament itself is large, so that the driving property during weaving is poor, and the weaving property is significantly reduced. .

The method described in Japanese Patent Application Laid-Open No. 55-11683 is characterized by adding a thermosetting resin to the weft yarn in order to improve the rigidity of the seat belt webbing in the weft direction. According to this method, the initial stiffness in the weft direction is certainly improved, but if the seat belt webbing is repeatedly subjected to bending fatigue, the applied thermosetting resin may be destroyed, and the stiffness in the weft direction is greatly reduced. Sometimes it dropped.

Further, the method described in Japanese Patent Publication No. 4-66984 discloses a method of improving slip resistance with a slip guide or the like by applying a specific resin to the surface of a seat belt webbing and storing the sheet in a retractor. It is characterized by improving the performance. According to this method, although the initial storability is certainly improved, when used for a long period of time, the resin applied to the surface is scraped off and falls off, so that the slip resistance gradually decreases, and accordingly In some cases, the storability also deteriorated.

Japanese Patent Application Laid-Open No. Hei 7-228218 proposes a seat belt webbing using synthetic fibers having a non-circular cross section as the weft. Although the rigidity in the latitudinal direction is improved, there are some that have little effect on the rigidity in the latitudinal direction depending on the cross-sectional shape and the fineness of the fiber, and the weaving property of the webbing is poor.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems in the prior art.
Has been achieved. Therefore, the object of the present invention is to
Synthetic fibers for seat belts with improved rigidity in the latitudinal direction than before, and excellent rigidity, especially rigidity in the latitudinal direction, stable storage properties, and less likely to invert the seat belt, in the event of an accident Another object of the present invention is to provide a seat belt webbing that can surely protect an occupant.

[0009]

In order to achieve the above object, the synthetic fiber for a seat belt of the present invention mainly has the following constitution. That is, the synthetic fiber is a single fiber having a triangular or Y-shaped multifilament having a cross-sectional shape of 1.5 to 4.0 and a single fiber fineness d of 4 to 40 denier. A synthetic fiber for seat belts, characterized in that:

In the synthetic fiber for a seat belt of the present invention, the multifilament has a fineness of 200 to 1
700 denier, strength of 4.0 g / d or more, fiber entanglement (CF value) of 10 or more, the synthetic fiber is made of original yarn, and the synthetic fiber is treated with a resin or a treating agent. And the synthetic fiber is preferably made of a polyester having ethylene terephthalate as a main repeating unit. By applying these conditions, further excellent effects can be expected.

The seat belt webbing of the present invention mainly has the following configuration. That is, the synthetic fiber is a single fiber having a triangular or Y-shaped multifilament cross section, and the single fiber has a degree of deformation (H) of 1.5.
A seat belt webbing characterized by using synthetic fibers for seat belts having a single fiber fineness d of 4 to 40 deniers as wefts.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below. It is important that the cross-sectional shape of the synthetic fiber used for the seat belt in the present invention is triangular or Y-shaped. That is, by making the cross section of the fiber triangular or Y-shaped, when the cross section of the single fiber is the same, the bending rigidity of the single fiber becomes higher than that of a fiber having a normal circular cross section.
Further, by making the cross section of the fiber triangular or Y-shaped, the contact surface between the single fibers is increased, and as a result, the rigidity of the webbing is increased.

However, in the case of the synthetic fiber used in the present invention, which has a triangular or Y-shaped multifilament, the degree of deformation (H) of the single fiber is 1.5 to 1.5.
It is important to be in the range of 4.0, preferably 1.7-3.8. When the degree of deformation (H) of the single fiber is less than 1.5, the webbing rigidity cannot be obtained. On the other hand, when it exceeds 4.0, the single fiber breaks during spinning-drawing and the quality deteriorates, which is not preferable. .

Further, in the synthetic fiber used in the present invention, which has a triangular or Y-shaped multifilament, the single fiber has a single fiber fineness (d) of 4 to 40 denier, preferably 6 to 25 denier. It is important that there is. If the single fiber fineness is less than 4 denier, the rigidity of the single fiber is not obtained because the rigidity of the single fiber is small, and if it is 40 denier or more, the rigidity of the single fiber is too large, Not only is the driving property during weaving deteriorated, but also the monofilaments projecting from the end faces of the ears of the webbing directly touch the occupant's skin when wearing the seat belt, which gives an uncomfortable feeling. .

The fineness (D) of the synthetic fiber for seat belt of the present invention is preferably 200 to 1700 denier, and the strength is preferably 4.0 g / d or more. By setting these ranges, it is possible to have a high strength so as to withstand the impact of a vehicle collision for the purpose of protecting the occupant when the webbing is made, and without increasing the thickness of the webbing, It can be pulled out smoothly from the retractor, and can be stored smoothly in the retractor when removed.

Further, the synthetic fiber for a seat belt of the present invention preferably has an entanglement degree (CF value) of 10 or more, particularly preferably 15 or more. When the degree of entanglement is in such a range, non-twisted synthetic fibers are generally used during webbing weaving, but the weft driving performance does not decrease.

The synthetic fiber for a seatbelt of the present invention is preferably made of original yarn, since it can be recycled and has excellent light fastness. As a method of soaking, for example, a method of adding a coloring agent in an esterification step for polyester polycondensation, which is a material polymer, or a transesterification step, or a polycondensation reaction step, a method of spinning by blending a coloring agent during chip drying , A method of directly adding a colorant during spinning, a method of melting a master chip containing a high concentration of a colorant, blending with a separately melted base polymer and spinning (melt blending method), and a method of high-concentration of a colorant. Method of spinning by blending the contained master chip and base chip (chip blending method)
Conventionally known addition techniques such as can be applied, and any colorant addition time can be selected, but in consideration of fiber quality, operation stability and production cost, among others, chips using a master chip The use of a blending method is preferred.

In addition, the synthetic fiber for a seat belt of the present invention is preferably subjected to a low friction treatment with a low friction treatment agent. That is, by performing the friction reduction processing, it is possible to maintain the storage stability of the seat belt webbing satisfactorily. As the low friction treatment agent used here, a treatment agent containing a polyether compound having a molecular weight of 1,000 to 3,000 is preferable. As a method of applying the friction-reducing agent, it can be applied at any position after spinning and before winding. As a specific application method, for example, a method in which a low friction treatment agent is mixed with a spinning oil and applied, and a method in which the agent is applied immediately before winding are exemplified. Alternatively, the webbing may be applied after weaving the seatbelt yarn to form webbing. Specifically, for example, a method in which the webbing is immersed in a solution of the low friction processing agent, a method in which the solution of the low friction processing agent is sprayed on the webbing surface, and the like can be arbitrarily selected.

The raw material polymer for the seatbelt fiber of the present invention includes polyester and polyamide, but polyester is preferably used from the viewpoint of initial modulus and terminal modulus. As the type of polyester, particularly, polyester having ethylene terephthalate as a main repeating unit, that is, polyethylene terephthalate is preferably used. In the polyethylene terephthalate, a conventionally known acid component and glycol component may be copolymerized as long as the constitutional requirements and objects of the present invention are not impaired, and specific examples of the acid component include isophthalic acid and adipic acid. However, specific examples of the glycol component include tetramethylene glycol, 1,4
-Cyclohexane dimethanol and polyethylene glycol.

The synthetic fiber for a seat belt of the present invention can be obtained by a usual spinning method. For example, a polyester base chip and a master chip are weighed and mixed, respectively, and the mixed chip is supplied to an extruder to form a molten polymer and spun from a die having a Y-shaped hole. After passing the spun yarn through a heating cylinder such as a heating cylinder or a heat insulating cylinder,
It is cooled and solidified by cold air. Then, after applying a spinning oil containing a low friction treatment agent, a take-up speed of 400 to 800 m
/ Min is taken up by a take-up roll whose peripheral speed is controlled. The drawn undrawn yarn is usually drawn without winding. Of course, the film may be stretched after being wound once. The undrawn yarn was heated and controlled to 70 to 120 ° C. 2
After giving a 1-10% pre-stretch between the pair of supply rolls, the process is led to a substantial stretching step. Stretching is usually performed in two or more steps. The stretching ratio is in the range of 3.0 to 7.0 times. After heat-setting at a temperature of 180 ° C. or higher, preferably 200 ° C. or higher simultaneously with the stretching, the film is subjected to a relaxation treatment at a relaxation rate of 1 to 3% or more by a relax roll, and then wound up into a package by a winder. Immediately before the winder, the entanglement is imparted by the entanglement nozzle, whereby the fiber for the seat belt of the present invention is obtained.

The seatbelt webbing of the present invention can be obtained by weaving the synthetic fiber for a seatbelt having the above structure as a weft and weaving it by a usual weaving method.
The warp is not particularly limited, and synthetic fibers having a normal circular cross section can be used. In this case, as the warp material, it is desirable to use a polyester mainly composed of polyethylene terephthalate as in the case of the weft.

The webbing for a seat belt of the present invention having the above-mentioned structure has a cross-sectional shape of a synthetic fiber constituting the webbing.
Because the degree of deformation (H) and fineness are specified in specific ranges,
Compared to conventional webbing for seat belts, it has improved rigidity in the weft direction, has stable storage properties, is unlikely to cause seat belt reversal, and ensures occupants in the event of an accident. Can be protected.

[0023]

Next, the present invention will be described in detail with reference to examples. Each measurement value in the examples was measured according to the following method.

[Deformation (H)] A section of a single fiber cross section was prepared by a copper plate method, and the radius (r) of the inscribed circle and the radius (R) of the circumscribed circle of the single fiber cross section were measured by an optical microscope. : Degree of deformation (H) = R / r.

[Strength] The strength was measured according to JIS L-1017 using a Tensilon tensile tester manufactured by Orientec.

[Confounding degree (CF value)] 1
Applying a load of 00g and lowering the hook of 6g by 1-2c
m / sec, and the equation: Entanglement degree (CF value) = 100 (c
m) / Descent distance (cm).

[Static Tensile Strength, Static Tensile Elongation] Using a tensile tester “Tensilon” manufactured by Orientec, JI
Measured according to SL-1079, 6.12.

[Bending rigidity in the weft direction] Using a rigidity tester (Model 150-B) manufactured by US Taper Co., Ltd., a width of 50 cm
It was measured under the condition of a length of 100 cm.

(Examples 1 to 6, Comparative Examples 1 to 3) A polyester chip was melted and spun from a die having a non-circular hole, that is, a Y-shaped hole or a triangular-shaped hole.

In Comparative Example 1, the fiber was spun from a die having a circular hole.

After passing the spun yarn through a heat retaining cylinder such as a heating cylinder or a heat insulating cylinder, it is cooled and solidified by 30 m / min of cold air,
Next, after applying the oil agent, it was taken up by a take-up roll whose peripheral speed was controlled to a take-up speed of 700 m / min.

Next, the drawn undrawn yarn is given a 3% pre-stretch between two pairs of supply rolls that are continuously heated and controlled at 70 to 120 ° C., and then the drawing ratio is set to 4.
The film was stretched in the range of 0 to 7.0 times.

After heat-setting at a temperature of 110 to 220 ° C. at the same time as the stretching, the film was subjected to a relaxation treatment at a relaxation rate of 1.5% by a relaxation roll, and then wound up in a package by a winder.

The fineness of the synthetic fiber thus obtained,
Table 1 shows the number of filaments, the strength and the degree of entanglement.

[0035]

[Table 1]

Further, the obtained synthetic fiber was wound with a needle loom at a number of wefts of 20 / inch and a warp of 39.
Weaving was performed under the condition of 0 yarns / inch, and then heat setting was applied to obtain a seat belt webbing having the configuration shown in Table 1. In this case, the warp has a fineness of 1
Polyester multifilament with 500 denier and 144 filaments (strength 9.5 g / d, elongation 12%)
Was used.

Table 1 also shows the static tensile strength (ton), static tensile elongation (%) and bending stiffness in the weft direction (g · cm) of the obtained seat belt webbing.

As is clear from the results in Table 1, the seatbelt webbing of the present invention (Examples 1 to 6) using synthetic fibers having a triangular or Y-shaped non-circular cross-sectional shape is the same as the conventional one having a circular cross-section. Compared to seat belt webbing,
The rigidity in the weft direction is greatly improved.

[0039]

As described above, the synthetic fiber for a seat belt of the present invention has a further improved rigidity in the weft direction than before, and the synthetic fiber for a seat belt of the present invention using this synthetic fiber for a seat belt as a weft yarn. Compared to conventional seatbelt webbing, the seatbelt webbing has significantly improved rigidity, particularly in the weft direction, and has a stable retractability in the retractor. If an accident is encountered, the occupants can be reliably protected.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D018 BA01 BA02 BA04 4L033 AA04 AA07 AB01 AC15 BA00 BA98 CA00 CA48 CA69 4L035 BB31 BB91 CC07 DD02 FF01 4L045 AA05 BA03 BA13 BA14 BA49 BA57 BA60 DA09 DA17 DA23 DA42 DC02

Claims (6)

[Claims] 1. A synthetic fiber comprising a multifilament having a triangular or Y-shaped cross section, wherein the single fiber has a degree of deformation (H) of 1.5 to 4.0 and a single fiber fineness d of 4
A synthetic fiber for a seat belt, which is 40 to 40 denier. 2. The multifilament has a fineness of 200.
The synthetic fiber for a seat belt according to claim 1, wherein the fiber has a fiber entanglement (CF value) of 10 to 1700 denier, a strength of 4.0 g / d or more, and 10 or more. 3. The synthetic fiber for a seat belt according to claim 1, wherein the synthetic fiber is made of a native yarn. 4. The synthetic fiber for a seat belt according to claim 1, wherein the synthetic fiber is treated with a resin or a treating agent. 5. The synthetic fiber for a seat belt according to claim 1, wherein the synthetic fiber is made of polyester having ethylene terephthalate as a main repeating unit. 6. A seat belt webbing using the synthetic fiber for a seat belt according to claim 1 as a weft.