JP2001146655A - Base fabric for air bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base fabric which is used for air bags, is excellent in mechanical characteristics such as strength and elastic modulus and in adhesivity to coating materials, is stable against heat and moisture, and has excellent air bag operability. SOLUTION: This base fabric for air bags, characterized by containing polyketone fibers formed from a polyketone polymer comprising an olefin-carbon monoxide copolymer in at least one part of a fabric composing the base fabric.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag having excellent mechanical properties, excellent adhesion to a coating material, excellent stability against heat and humidity, and excellent airbag operability. The present invention relates to a base fabric and an airbag formed from the base fabric.

[0002]

2. Description of the Related Art In recent years, as one of safety devices for protecting occupants of automobiles, the mounting rate of airbags has been rapidly increasing.
The airbag device is a gas generator (inflator) when a sensor detects the shock of a collision in the event of a car collision.
There is a device that generates a high-temperature and high-pressure gas in an airbag base fabric and instantaneously inflates and deploys the airbag, thereby protecting the occupant's body from the impact at the time of a collision. Conventionally, airbags use plain fabrics, knits, or nonwoven fabrics as base fabrics using general-purpose fiber filaments made of polyamides such as nylon 6 or nylon 6.6, or polyesters such as polyethylene terephthalate. In order to improve heat resistance, flame retardancy, gas barrier properties, etc., these cloths are coated and laminated with an elastomer such as a synthetic rubber or natural rubber such as silicon, chloroprene, or chlorosulfonated olefin as a base cloth. It is made by cutting and sewing a base cloth.

[0003] Since a very strong impact is applied to the base fabric for an airbag when the airbag is operated (during inflation and deployment), the fabric used for the base fabric has mechanical properties enough to withstand this shock. There is a need. However, general-purpose fibers such as polyamide and polyester have low strength and mechanical properties typified by elastic modulus, so the fineness of the filament used and the basis weight of the woven or knitted fabric must be increased, resulting in the weight and weight of the airbag. The capacity has become large, and it has become a major problem in the field of automotive parts where the progress of weight reduction and compactness is remarkable. Normally, airbags are stored in the passenger compartment, such as the steering wheel and instrument panel.However, the passenger compartment is hot for a long time in summer or under hot weather, and for a long time in the humid rainy season or rainy weather. It will be placed in a humid environment. For this reason, polyamide and polyester, which are polycondensation polymers, are liable to deteriorate in mechanical properties, and there is a problem in long-term stable operation of the airbag.

[0004] In recent years, in order to solve these problems of general-purpose fibers, airbags using fibers of high strength and high elastic modulus such as ultra-high molecular weight polyethylene fibers, polyvinyl alcohol fibers, and aramid fibers have been studied. (For example, JP-A-4-146233). However, polyethylene fiber has a low melting point and insufficient heat resistance, polyvinyl alcohol fiber has poor mechanical properties at high temperature and high humidity, and aramid fiber has good adhesion to coating materials such as silicon and rubber. There were problems such as bad. As described above, there is no known airbag fabric having all of the mechanical properties, heat resistance, heat and moisture resistance, and adhesiveness with a coating material in automobile airbags.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a base fabric for an airbag which is excellent in all of mechanical properties, heat resistance, heat and humidity resistance and adhesiveness to a coating material.

[0006]

As a result of various studies on the above-mentioned problems, the present inventor has found that as a fiber constituting an airbag base fabric, a polyketone composed of a polyketone polymer comprising a copolymer of olefin and carbon monoxide is used. It has been found that the above problems can be solved by using fibers, and the present invention has been completed. That is, the present invention provides: A base fabric for an airbag, wherein at least a part of a fabric constituting the base fabric includes a polyketone fiber composed of a polyketone polymer comprising a copolymer of olefin and carbon monoxide. Provide a cloth. The polyketone fiber is characterized in that the strength is 5 cN / dtex or more and the elastic modulus is 100 cN / dtex or more. Also, the strength of the polyketone fiber is 10 cN / dtex or more,
It is characterized in that the elastic modulus is 200 cN / dtex or more. Further, it is characterized in that 97% by weight or more of the repeating units constituting the polyketone polymer are 1-oxotrimethylene. Further, the polyketone polymer is characterized in that the repeating unit is composed of only 1-oxotrimethylene. Further, it is characterized in that 50% by weight or more of the fabric constituting the base fabric for an airbag is a polyketone fiber. Further, it is characterized in that the fabric constituting the base fabric for an airbag is made of only polyketone fibers. Further, the airbag fabric is made of a plain fabric, and the fabric has the following mechanical characteristics (1) and (2). Further, tear strength ≧ 700 (N) (1) Cover factor K: 1500 ≦ K ≦ 3000 (2) Provided is an airbag composed of the base fabric for an airbag described in any of the above. I do.

Hereinafter, the present invention will be described in detail. The polymer constituting the polyketone fiber used as at least part or all of the fabric constituting the base fabric for an airbag of the present invention is a copolymer of olefin and carbon monoxide. From the viewpoints of mechanical properties such as strength and elastic modulus, heat resistance, heat and humidity resistance, and adhesiveness, a polymer having 1-oxotrimethylene as a main repeating unit in which ethylene and carbon monoxide are bonded is preferred. The proportion of 1-oxotrimethylene in the repeating unit is preferably 90% by weight or more because the higher the ratio, the higher the melting point and the fibers having high mechanical properties can be obtained.
More preferably, it is 97% by weight or more.

In the repeating unit in which olefin and carbon monoxide are bonded, ketone groups and olefins may be partially connected, but at least 90% by weight of olefin and carbon monoxide are alternately arranged. Desirably, it is a polyketone polymer. From the viewpoints of light resistance, heat resistance, and a decrease in physical properties at high temperatures, the content of the portion in which olefins and carbon monoxide are alternately arranged is preferably as large as possible, and preferably 9
It is at least 7% by weight, most preferably 100% by weight. In addition, if necessary, olefins other than ethylene such as propene, butene, hexene, cyclohexene, pentene, cyclopentene, octene, and nonene, methyl methacrylate, vinyl acetate, acrylamide, hydroxyethyl methacrylate, styrene, sodium styrene sulfonate, and allylsulfonic acid Sodium, vinylpyrrolidone,
A compound having an unsaturated hydrocarbon such as vinyl chloride may be copolymerized. Although the ratio of these other copolymer components is not particularly limited, it is usually 0 to 10%.

It is recommended that the polyketone fiber used for the airbag base fabric of the present invention has a strength of at least 5 cN / dtex and an elastic modulus of at least 100 cN / dtex. Since the strength of the base fabric per weight becomes higher as the fiber strength becomes higher, it is preferably 5 cN / dtex or more, more preferably 10 cN / dtex or more. In addition, since the rigidity of the base fabric is improved as the elastic modulus of the fiber is higher, it is preferably 100 cN / dtex or more, more preferably 200 cN / dtex or more.

[0010] Further, it is desired that the heat resistance is excellent in dry heat and wet heat resistance typified by dry heat shrinkage and strength after wet heat treatment. The dry heat shrinkage rate is 18 without tension.
The dry heat shrinkage after dry heat treatment at 0 ° C. for 30 minutes is preferably 5
%, More preferably 3% or less. The strength after wet heat treatment is preferably at least 5 cN / dtex, more preferably at least 10 cN, after the heat treatment at 120 ° C. and 100% humidity for 30 minutes.
It is desirable that the strength be N / dtex or more.

The polyketone fiber having such characteristics is used for at least a part of a fabric constituting a base fabric for an airbag. The higher the proportion of polyketone fibers in the fabric constituting the base fabric for an airbag, the better the mechanical properties, the dry heat / moisture heat resistance, and the adhesion to the coating material. Preferably 80% by weight or more, particularly preferably 100% by weight, is a polyketone fiber. The fineness of the polyketone fiber is not particularly limited because it varies depending on the use environment of the airbag, the form of the base fabric, and the mixing method. However, in the case of 100% by weight of the polyketone fiber, the single fiber fineness is 0.1 to 10 dtex, and the total fineness is 20 to 20%. 10
00dtex is preferred.

The fabric form of the base fabric for an airbag of the present invention is not particularly limited, and may be a form or a structure such as a plain woven fabric, a knitted fabric, or a non-woven fabric, but is preferably a woven fabric from the viewpoint of mechanical strength. Preferably, plain fabrics are particularly preferred. The basis weight and density of the fabric are not particularly limited, but the thickness of the fabric is 0.0
5 to 10 mm is preferable, and 0.1 to 1 mm is more preferable. In the case of woven fabric, the basis weight of warp and weft is 1
The number is preferably 0 to 500 lines / inch, more preferably 20 to 300 lines / inch. The cover factor calculated from the fineness and the fabric density is preferably in the range of 500 to 5000, more preferably in the range of 1500 to 3500. In addition,
In the present invention, the cover factor K is calculated by the following equation (3) when the fineness of the warp and the weft is Dt and Dw (dtex), and the basis weights of the warp and the weft are Mt and Mw (book / inch), respectively. It is a numerical value. K = Mt × Dt ^0.5 + Mw × Dw ^0.5 (3) The mechanical strength of the base fabric for an airbag is typically a tear strength. Since the tear strength depends on the cover factor, it is difficult to define it uniformly,
The base fabric of the present invention has a cover factor K of 1500 to 300.
The tear strength at 0 is preferably 700 N or more, more preferably 800 N or more.

The fibers which can be mixed with the polyketone fibers in the airbag base fabric of the present invention are not particularly limited.
Polyamide fiber such as nylon 6, nylon 6.6, nylon 4.6, polyester fiber such as polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, liquid crystal polyester fiber, polyolefin fiber such as polyethylene, polypropylene, polyvinyl alcohol fiber, polybenzazole Fiber, aramid fiber, wool, polyacrylonitrile fiber, cotton, cellulose fiber such as viscose rayon, carbon fiber, ceramic fiber, conventionally known fiber such as metal fiber can be used, and if necessary, these fibers can be used. There is no problem even if a plurality of types of fibers are used in combination. The proportion of the fiber that can be mixed with the polyketone fiber is not particularly limited, but is usually 50% by weight or less, preferably 20% by weight or less.

The fibrous material used for the base fabric of the present invention is preferably non-twisted. In some cases, however, it is possible to use a processed yarn which has been subjected to false twisting, bulking, crimping, winding, or the like. good. When mixing multiple types of fibers, there is no particular limitation on the method, and different types of fibers are used for the warp and weft, and if necessary, multiple types of fibers are subjected to processing such as false twisting or twisting. Mixed fibers, fibers of the same kind but with different thermal and mechanical properties, fibers with different fineness and filament count, or spun yarn of long filament and short fiber, etc. May be used.

The polyketone fibers used in the base fabric for an airbag of the present invention and the fibers to be mixed are heat stabilizers, leveling agents, pigments, oil agents, concealing agents, matting agents, flame retardants, plasticizers,
There is no problem even if additives such as flame retardants are included, and fibers containing various stabilizers and flame retardants are preferred. The airbag fabric produced under the above conditions is cut and sewn according to the shape of the target airbag. The method for manufacturing an airbag using a base cloth of the present invention includes the steps of sewing, bonding, press-compression bonding, vulcanization, thermocompression bonding, etc., alone or in combination with a plurality of base cloths, and weaving and knitting. Any method such as a method of producing a bag body by using the method described above may be used. The shape of the airbag may be any shape such as a circle, a sphere, an ellipse, and a rectangle.
The airbag may be used for any purpose such as a passenger seat, a rear seat, and a side. The airbag exhaust system using the airbag fabric of the present invention may be any of a full fabric exhaust system, a partial fabric exhaust system, an exhaust hole system, and a combination of these. May be.

Hereinafter, a method for producing a polyketone fiber used for a fabric constituting the base fabric for an airbag of the present invention will be described. The method for producing the polyketone fiber is not particularly limited,
Conventionally known melt spinning, dry spinning, and wet spinning can be used as they are or after modification (for example, JP-A-1-124617, JP-A-2-112413).
JP, JP-A-4-228613, JP-T-Hei-4-5
JP-A-05-344, JP-A-4-228613, JP-A-7-508317, JP-A-8-507328
Publication, WO9918143 published pamphlet, Japanese Patent Application No. 10-236595, Japanese Patent Application No. 11-72091.
Gazette, Japanese Patent Application No. 11-77220, and Japanese Patent Application No. 11-77220.
159258, Japanese Patent Application No. 11-167370). When spinning the ethylene / carbon monoxide alternating copolymer, a wet spinning method using a concentrated metal salt as a solvent is preferred.

The concentrated metal salt includes a zinc halide compound, and zinc chloride and zinc iodide are preferred in view of solubility, cost of the solvent, and stability of the aqueous solution. If necessary, the composition may contain 60% by weight or less of an alkali metal or alkaline earth metal halide such as sodium chloride, potassium chloride, and calcium chloride. In view of this, a dope containing 5 to 30% by weight of a metal salt such as sodium chloride or calcium chloride is preferable. The polyketone dope is discharged from a spinneret and, if necessary, is passed through an air gap to form a filament through a coagulation bath. The composition of the coagulation bath may be any one such as an organic solvent such as methanol and acetone, water, an aqueous solution of an organic substance, and an aqueous solution of an inorganic substance, but a solution containing water is preferred. The thus obtained filamentous material is washed with a metal salt as necessary, dried and stretched. Stretching is
It is usually performed at a temperature below the melting point, and the stretching ratio is 10 in total.
It is preferable to perform hot stretching at least twice, especially 15 times or more, and a multi-stage stretching method in which the stretching temperature is gradually increased is suitably used.

The polyketone fiber obtained by such a method has excellent mechanical properties such as high strength and high elastic modulus, is stable against heat and wet heat, and is bonded to a coating material such as rubber. By applying the fiber to the base fabric for airbags, it has excellent strength, stable operability and handleability that could not be obtained with conventional airbags made of fiber material. Now you can get an airbag.

[0019]

The present invention will be described in more detail with reference to the following examples, which do not limit the scope of the present invention. The measuring method of each measured value used in the description of the embodiment is as follows. (1) Intrinsic viscosity Intrinsic viscosity [η] is a value obtained based on the following defining equation (4). [Η] = lim (T−t) / (t · C) [g / dl] (4) C → 0 (where t and T are dilute solutions of polyketone dissolved in hexafluoroisopropanol) Is the flow time of the solution through a viscosity tube at 25 ° C. C is 100 ml of the above solution
The solute weight value in grams in. (2) Strength and elastic modulus Measured according to JIS-L-1013.

(3) Dry heat shrinkage The dry heat shrinkage was determined by measuring the values before and after the treatment at 180 ° C. according to JIS-L-1013. (4) Post-moisture heat treatment strength The fibers were put into an autoclave at a humidity of 100% and a temperature of 120 ° C, and treated for 30 minutes. The strength of the treated fiber was measured according to the method (2). (5) Tear Strength Measured for weft and weft according to JIS-L-1096, Method C. (6) Tear strength after wet heat treatment The base fabric was put into an autoclave at 100% humidity and 120 ° C for 30 minutes. The tear strength of the base fabric after the treatment was measured according to the above method (5).

(Example 1) A polyketone polymer having an intrinsic viscosity of 5.9, in which ethylene and carbon monoxide were completely alternately copolymerized, prepared by a conventional method, was added to an aqueous solution containing 65% by weight of zinc chloride / 10% by weight of sodium chloride. The mixture was stirred and dissolved at 80 ° C. for 2 hours to obtain a dope having a polymer concentration of 8% by weight. The obtained dope was heated to 80 ° C. and filtered with a 20 μm filter, and then a spinning diameter of 0.10 mm and L / D = 1,2.
After passing through an air gap of 10 mm from a 50-hole spinneret, the mixture was extruded into water at 18 ° C. containing 5% by weight of zinc chloride at a discharge rate of 12.5 cc / min to solidify.
The coagulated yarn is subsequently washed with a 2% by weight aqueous sulfuric acid solution,
Further, after washing with water at 30 ° C., a winding speed of 2.5 m
Per minute, and the obtained filamentous material was dried at 200 ° C. to obtain an undrawn yarn.

After the undrawn yarn is drawn at 240 ° C. in the first stage, it is subsequently drawn at 260 ° C. in the second stage and at 270 ° C. in 3 stages.
Stretching at the stage and stretching 15 times in total, 35
A drawn yarn of 0 dtex / 250f was obtained. Fluff during stretching
No trouble such as thread breakage occurred. The obtained fiber had excellent properties in both fiber physical properties and heat / wet heat stability.
The properties and properties of the fibers used in the base fabric for the airbag are shown in Table 1 together with the properties of the fibers used in Examples 2 to 4 and Comparative Examples 1 and 2 below. Using this drawn yarn,
A plain fabric having a weaving density of 60 yarns / inch in both weft and weft was woven, refined at 90 ° C, and heat-set at 180 ° C to obtain a base fabric for an airbag. The woven density of the obtained base fabric was 61 / inch in both the warp and weft, and the cover factor was 2282.
And exhibited excellent mechanical properties and moisture resistance. The properties and performance of the obtained base fabrics are shown in Table 2 together with the results of the base fabrics of Examples 2 to 4 and Comparative Examples 1 and 2 below.

(Example 2) Using the drawn yarn obtained in Example 1, a plain weave having a weaving density of 70 yarns / inch in both warp and weft was woven, refined at 90 ° C, and heated at 180 ° C. This was set to obtain a base fabric for an airbag. (Example 3) An ethylene / propene / carbon monoxide terpolymer having an intrinsic viscosity of 1.6 containing 6% by weight of 1-oxo-3-methyltrimethylene unit was prepared by a conventional method. Using the polymer, the dope concentration was 22% by weight,
An undrawn yarn was obtained by spinning and drying in the same manner as in Example 1 except that the discharge rate was 5 cc / min. This undrawn yarn is
After passing through a roll heated to 80 ° C.,
20m on a 1m long hot plate with heated air
After performing the first stage stretching at 0 ° C., the second stage stretching is performed at 215 ° C., and the third stage stretching is further performed at 225 ° C., and a total stretching of 12.5 times is performed, and the fineness is 380 dtex / 250.
Thus, a drawn yarn of f was obtained. The strength of this drawn yarn is nylon 6.6
Although it was almost the same as an airbag made, it was excellent in heat resistance and wet heat resistance. Using this drawn yarn, a plain woven fabric was woven, scoured, and heat-set in the same manner as in Example 1 except that the weaving density was 66 yarns / inch for both the warp and the weft to obtain a base fabric.

(Example 4) The drawn yarn obtained in Example 1 was used as a warp, and 351 dtex / 70f nylon 6.6 was used as a weft.
Using the fibers, weaving and heat setting were performed in the same manner as in Example 1 to obtain a base fabric for an airbag. A base fabric having excellent tearing strength not only in the warp direction but also in the weft direction was obtained. (Example 5) A plain fabric woven in Example 1 was coated with chloroprene rubber at 80 g / m ₂ and vulcanized under the conditions of 180 ° C for 80 seconds to obtain a surface-treated base fabric for an air bag. The adhesion between the woven fabric and the coated rubber of the base fabric was good, and no peeled portions or defects were observed even in repeated use tests.

(Comparative Example 1) Weaving, scouring and heat setting were carried out using 351 dtex / 70f nylon 6.6 fibers in the same manner as in Example 1, and the weaving density was 62.5 yarns for both warp and weft. An inch base cloth was obtained. The mechanical properties of the base fabric are significantly inferior to those of the polyketone fiber,
In particular, the tear strength was greatly reduced by the wet heat treatment. (Comparative Example 2) Polyvinyl alcohol having a degree of polymerization of 7000 and a degree of saponification of 100% by weight, prepared by a conventional method, was dissolved in DMSO so as to have a concentration of 7% by weight. To a fineness of 355
A dtex / 250f drawn yarn was obtained. The drawn yarn was subjected to weaving, scouring and heat setting in the same manner as in Example 1 to obtain a base fabric. The mechanical properties of the base fabric were the same as those using the polyketone fiber, but the tear strength was greatly reduced by the wet heat treatment.

[0026]

[Table 1]

[0027]

[Table 2] (Note) ECO = ethylene / carbon monoxide alternating copolymer (1
-Oxotrimethyl unit = 100% by weight, intrinsic viscosity =
5.9) EPCO = ethylene / propene / carbon monoxide terpolymer (1-oxo-3-methyltrimethylene unit = 6% by weight, intrinsic viscosity = 1.6) PA = nylon 6.6 (trade name “Leona 6”)・ 6 ”manufactured by Asahi Kasei Kogyo Co., Ltd.) PVA = polyvinyl alcohol (degree of saponification = 100% by weight, degree of polymerization = 7000)

[0028]

The airbag fabric of the present invention has high strength and
It contains polyketone fiber which has excellent mechanical properties with high elastic modulus, is stable against heat and wet heat, and also has excellent adhesiveness to a coating material such as rubber. By applying the present invention to an airbag made of a conventional fiber material, an airbag having excellent strength, stable operability and handleability, which cannot be obtained at all, can be obtained. As a result, it is possible to provide an airbag that can be further reduced in weight and size while having high performance.

Continued on the front page F-term (reference) GK01 GN00 4L048 AA14 AA24 AA48 AA51 AA53 AB07 AC09 AC12 BA01 BA02 CA01 CA15 DA25

Claims (9)

[Claims] 1. A base fabric for an airbag, wherein at least a part of a fabric constituting the base fabric includes a polyketone fiber made of a polyketone polymer made of a copolymer of olefin and carbon monoxide. Base fabric for airbags. 2. The polyketone fiber has a strength of 5 cN / dte.
2. The base fabric for an airbag according to claim 1, wherein the base fabric has an elastic modulus of 100 cN / dtex or more. 3. The strength of the polyketone fiber is 10 cN / dt.
The airbag fabric according to claim 1 or 2, wherein the elastic modulus is at least ex and the elastic modulus is at least 200 cN / dtex. 4. The base fabric for an airbag according to claim 1, wherein 97% by weight or more of the repeating units constituting the polyketone polymer is 1-oxotrimethylene. 5. The base fabric for an airbag according to claim 1, wherein the repeating unit constituting the polyketone polymer comprises only 1-oxotrimethylene. 6. The fabric 50 constituting the base fabric for an airbag.
The base fabric for an airbag according to any one of claims 1 to 5, wherein the weight percent or more is a polyketone fiber. 7. A fabric constituting a base fabric for an airbag, comprising a polyketone fiber only.
The base fabric for an airbag according to any one of the above. 8. The airbag fabric according to claim 1, wherein the fabric is a plain fabric, and the fabric has the following mechanical properties (1) and (2). Base fabric for airbags. Tear strength ≧ 700 (N) (1) Cover factor K: 1500 ≦ K ≦ 3000 (2) 9. An airbag comprising the base fabric for an airbag according to claim 1.