JP4453039B2 - Airbag fabric - Google Patents

Description

  The present invention relates to an airbag fabric, and more particularly, to an airbag fabric that is one of the safety devices of automobiles that is low in cost, excellent in restraining performance of the human body, and easily recyclable as an uncoated fabric.

  In recent years, airbags, which have been rapidly installed as one of the safety parts of automobiles, have detected high-pressure, high-pressure gas from the inflator when a car crash occurs. When the airbag is suddenly deployed and the body of the driver or passengers jumps out in the colliding direction, the head particularly prevents and protects the head from colliding with the handle, the windshield, the door glass and the like. Conventionally, coated fabrics coated with synthetic rubber such as chloroprene, chlorosulfonated olefin, and silicone have been used for airbags because of their high heat resistance, air barrier properties (low air permeability), and high flame retardancy.

  However, fabrics coated with these synthetic rubbers have many disadvantages when used as airbag fabrics because the fabric weight increases, the flexibility is not satisfactory, and the production cost is high. Moreover, easy recycling was difficult.

There has been proposed a method in which a fabric can be recycled by immersing a silicone-coated cloth in an alkaline solution, dehydrating, and then peeling and removing the silicone coating layer (for example, Patent Document 1). However, there is a problem that a process for peeling and removing the silicone is required, resulting in an increase in cost.
Japanese Patent Laid-Open No. 2001-180413

An airbag in which a non-coated cloth and a reinforcing cloth are peelably attached has been proposed (see, for example, Patent Document 2), but the reinforcing cloth has a heat-resistant coating and is difficult to recycle. There is a point.
Japanese Utility Model Publication No. 7-22867

Various other proposals have been made on recyclable non-coated fabrics (see, for example, Patent Documents 3-5). However, since it is a non-coated cloth, the air permeability is high, and there are problems inferior to the restraining performance of the human body when the airbag is deployed.
JP-A-8-192705 JP-A-9-11832 JP 11-78747 A

  The present invention seeks to provide an airbag fabric that is one of the safety devices that can be recycled as easily as a non-coated fabric at a low cost, which is unsolvable by the above-described conventional methods, and is excellent in human restraint performance. To do.

The present invention has the following configuration in order to solve the problems that could not be achieved by the above conventional method.
1. A fabric in which a thermoplastic synthetic resin is applied to at least one surface of a synthetic fiber fabric having a cover factor of 1500-2500, the thermoplastic synthetic resin being a polyamide-based resin, and a molecular weight of 100 to A synthetic fiber having a soft segment of 5000 , an air permeability under a differential pressure of 100 kPa of 1.0 L / cm 2 / min or less, and a morphological structure in a re-pellet produced by directly cutting the fabric. The thermoplastic synthetic resin is substantially uniformly dispersed in the resin derived from the woven fabric, and the dispersion average particle diameter of the thermoplastic synthetic resin in the resin derived from the synthetic fiber woven fabric is 2 μm or less. Airbag fabric.
2. ^{2. The} airbag fabric according to 1, wherein the adhesion amount of the thermoplastic synthetic resin is 0.1 to 15 g / m ² in terms of mass after drying.
3. 3. The airbag fabric according to any one of the above 1 or 2, wherein the elongation at break of the film product made of the thermoplastic synthetic resin is 300% or more.
4). 4. The airbag fabric according to any one of 1 to 3, wherein the soft segment has a molecular weight of 300 to 3000.
5). 4. The airbag fabric according to any one of 1 to 3, wherein the soft segment has a molecular weight of 600 to 1500.

  ADVANTAGE OF THE INVENTION According to this invention, the fabric for airbags which is one of the vehicle safety devices which can improve the restraint performance of a human body at low cost and can be recycled easily like a non-coat cloth can be provided.

Hereinafter, the present invention will be described in detail.
In the present invention, the material for the synthetic fiber is not particularly limited. In particular, aliphatic polyamide fibers such as nylon 66, nylon 6, nylon 46, and nylon 12, aromatic polyamide fibers such as aramid fiber, polyethylene terephthalate, Polyester fibers such as polybutylene terephthalate are used. Other examples include wholly aromatic polyester fibers, ultrahigh molecular weight polyethylene fibers, PPS fibers, and polyether ketone fibers. However, in consideration of economy and recyclability, polyester fibers and polyamide fibers are preferable, and polyamide fibers are more preferable. Further, these fibers may be obtained from raw materials that are partially or wholly reused. Moreover, in order to improve the process passability in the raw yarn manufacturing process and the post-processing process, these synthetic fibers have no problem even if they contain various additives. For example, antioxidants, heat stabilizers, smoothing agents, antistatic agents, thickeners, flame retardants and the like. Moreover, there is no problem even if this synthetic fiber is dyed after original yarn or after yarn production. Further, the cross section of the single yarn may be an irregular cross section in addition to the normal round cross section.

In the present invention, the weaving method is not particularly limited, but plain weaving is preferable in consideration of the uniformity of the fabric physical properties. The yarn to be used may not be a single warp or weft. For example, the thickness, the number of yarns, and the type of fiber may be different, but considering the recyclability, the type of polymer may be one. preferable. The loom is not particularly limited, such as an air jet loom, a rapier room, or a water jet loom. As a woven fabric, it is necessary that the cover factor shown by Formula 1 is 1500-2500. If it is less than 1500, the air permeability increases and the misalignment of the airbag sewing portion becomes large, which is not preferable. When it is larger than 2500, rigidity is increased, and storage properties are deteriorated. More preferably, it is 1800-2300.
Cover factor = (warp fineness (dtex) × 0.9) ^1/2 × warp density (line / 2.54 cm)
+ (Weft fineness (dtex) × 0.9) ^1/2 × weft density (main / 2.54 cm) (Formula 1)

  The fabric in this invention is manufactured by apply | coating a thermoplastic synthetic resin to the textile fabric woven by the well-known method. Thermosetting silicone resin is widely used as the coating agent for existing airbags, but the cost increases due to the need for sufficient heat for curing, and the dispersibility in re-pelletization deteriorates. Therefore, in the present invention, it is essential to use a thermoplastic resin. The coating method is not particularly limited, and a known method can be used, but it is preferable to use knife coating in consideration of cost and fabric flexibility after coating.

  In the present invention, a polyurethane resin, an acrylic resin, a polyester resin, and a polyamide resin can be used as the thermoplastic synthetic resin applied to the woven fabric, but a polyamide resin containing a soft segment having a molecular weight of 100 to 5000 is used. Is preferable from the viewpoint of dispersibility in re-pelletizing. More preferably, the molecular weight is 300-3000. If the molecular weight is less than 100, the base fabric flexibility after coating is lost, which is not preferable. If the molecular weight is more than 5000, combustibility deteriorates, which is not preferable. Here, the soft segment refers to the entire polyol, and in particular, an amino-modified product of linear polyalkylene glycol is preferable from the viewpoint of the dispersibility of the thermoplastic resin in the regeneration pelletization, and more preferably polyethylene glycol, polypropylene glycol, polytetra It is an amino modified product of methylene glycol or polybutylene glycol. The soft segment is preferably 25-50% of the polyamide resin in a molar ratio in the polymer. If it is 25% or less, the flexibility of the fabric after application is lost and the air permeability is increased. If it is 50% or more, the combustibility deteriorates, which is not preferable. These thermoplastic synthetic resins may be used in admixture with additives such as deterioration inhibitors, inorganic fillers, colorants and the like as long as the target performance is not affected.

In the present invention, the air permeability under a 100 kPa differential pressure of the fabric formed by applying a thermoplastic synthetic resin is required to be 1.0 L / cm ² / min or less. When a normal airbag is deployed, a force of 30-50 kPa is applied, but there is also the influence of heat from the inflator's explosives, so when measuring the fabric in the standard state, it is necessary to discuss the air permeability under a differential pressure of 100 kPa. is there. Preferably, not more than 0.5L ^/ cm 2 ^/ min, more preferably not more than 0.1L ^/ cm 2 ^/ min. When the air permeability under a differential pressure of 100 kPa is higher than 1.0 L / cm ² / min, it is not preferable because the occupant restraint performance when used as an airbag cannot be satisfied. In order to set the air permeability to 1.0 L / cm ² / min or less, for example, it can be achieved by setting the elongation of the resin film to be applied to a high elongation of 300% or more. The elongation of the resin film product is preferably large, and no particular upper limit is provided, but it may be 2000% or less. In the air permeability in JIS-L1096, preferably less than 0.1cc ^/ cm 2 ^/ sec.

  In the present invention, an almost thermoplastic synthetic resin is contained in a resin derived from a woven fabric in which the morphological structure (surface structure of the cross section) in the re-pellet produced by directly cutting the fabric is a continuous phase corresponding to the sea of the sea-island structure. It is preferable to disperse substantially uniformly. Here, being uniformly dispersed means that the thermoplastic synthetic resin is independently present in the continuous phase, and the dispersion average particle diameter is 2 μm or less. Preferably it is 0.5 micrometer or less. In the case of having such a morphological structure, a molded product produced from the re-pellet can satisfy the strength, rigidity, elongation, and impact resistance at the same time, and there are various uses.

In the present invention, the weight of the thermoplastic synthetic resin after drying is preferably 0.1-15 g / m ² , more preferably 1.0-10 g / m ² , and still more preferably 1.0-5.0 g / m ^2. a m ^2. The mass after drying is obtained by subtracting the value obtained by measuring the mass after application according to JIS L1096 8.4.2 from the value obtained by measuring the mass before application according to JIS L1096 8.4.2. . When the amount is less than 0.1 g / m ^2, undesirably can not achieve the air permeability, the strength of 15 g / m ² more than the dispersibility is deteriorated molded product during re pelletizing, stiffness, elongation, impact resistance at the same time It is not preferable because it is not satisfactory and the cost increases.

  As a recycling method, the recovered fabric is used as it is or cut and reused as a cushioning material, etc., the recovered fabric is re-melted or re-dissolved and then re-molded into a fiber or plastic material, etc. There is a so-called chemical recycling method for depolymerizing the used fabric to a monomer and reusing it. Recycling in the present invention is a method of re-molding a collected fabric into chips after remelting or re-dissolving the collected fabric from the viewpoint of versatility and cost. In the present invention, the cloth formed by applying the synthetic resin can be remelted and remelted as it is, and remolded.

  Next, the present invention will be described in more detail with reference to examples. Various evaluations in the examples were performed according to the following methods.

(Air permeability)
The air permeability under a pressure of 100 kPa was measured using a high pressure air permeability measuring machine (manufactured by OEM System Co., Ltd.). Further, in accordance with JISL1096, the air permeability under a 125 Pa differential pressure was also measured with a Fragil tester.

(Resin film elongation)
A film having a uniform thickness of 0.3 mm was made of a thermoplastic synthetic resin, a tensile test was performed at a speed of 300 mm / min with a gap between chucks of 35 mm, and the elongation at break was measured.

(Morphological structure)
The fabric was cut into 5 mm pieces, thermally melted at 270 ° C., and re-pellet was obtained with a PCM30 extruder (L / D = 25 manufactured by Ikekai Tekko Co., Ltd.). The re-pellet product was observed using a transmission electron microscope (JEM2010 manufactured by JEOL Ltd.) and an optical microscope (differential interference microscope manufactured by Nikon). In the transmission electron microscope, the sample was cut into ultrathin sections so as to be perpendicular to the flow direction of the resin, and a sample stained with ruthenium tetroxide for 30 minutes was observed.

(Re-pellet property evaluation)
The re-pellet product was dried with an 80 ° C. vacuum dryer for 16 hours and then injection molded to produce a test piece. The physical properties of the molded product were evaluated using this test piece.
Tensile strength / tensile elongation: ASTM D638
Flexural strength and flexural modulus: ASTM D790
Izod impact (with notch): ASTM D256

Example 1
Polyamide 66 fibers with a total fineness of 350 dtex and 108 filaments are woven in a plain jet weave in a water jet loom, shrink-processed with boiling water, dried at 110 ° C., warp density 63 / 2.54 cm, weft density 61 A fabric / 2.54 cm woven fabric was obtained. A polymer prepared by adjusting the molar ratio of polyamide 6, polyethylene glycol-propylamine adduct (molecular weight 600) and adipic acid to 2.5: 1: 1 was prepared as an aqueous resin having a solid content of 15%, and a knife. The properties of the fabric having a resin amount of 3 g / m ² after drying by coating were evaluated and are shown in Table 1.

(Example 2)
Polyamide 66 fibers with a total fineness of 350 dtex and 108 filaments are woven in a plain jet weave in a water jet loom, contracted with boiling water, dried at 110 ° C., warped density 59 / 2.54 cm, weft density 59 A fabric / 2.54 cm woven fabric was obtained. A polymer prepared by adjusting the molar ratio of polyamide 6, polyethylene glycol-propylamine adduct (molecular weight 1500) and adipic acid to 2.5: 1: 1 was prepared as an aqueous resin having a solid content of 15%, and a knife. The properties of the fabric with the resin amount after drying by a coat of 7 g / m ² were evaluated and are shown in Table 1.

(Example 3)
Polyamide 66 fibers with a total fineness of 350 dtex and 108 filaments are woven in a plain jet weave in a water jet loom, contracted with boiling water, dried at 110 ° C., warped density 59 / 2.54 cm, weft density 59 A fabric / 2.54 cm woven fabric was obtained. A polymer prepared by adjusting the molar ratio of polyamide 6, polyethylene glycol-propylamine adduct (molecular weight 600) and adipic acid to 2.5: 1: 1 was adjusted as an aqueous resin having a solid content of 10%. The properties of the fabric with the resin amount after drying at 7 g / m ² were evaluated and shown in Table 1.

Example 4
Same as Example 1 except that polyamide 66 fibers with a total fineness of 470 dtex and 72 filaments are used, the finishing density is warp density 46 / 2.54 cm, weft density 46 / 2.54 cm, and the resin amount is different. The properties of the fabric were evaluated and are shown in Table 1.

(Example 5)
Table 1 shows the properties of the same fabric as in Example 4 except that the finishing density is warp density 54 / 2.54 cm, the weft density 54 / 2.54 cm, and the resin amount is different.

(Comparative Example 1)
Polyamide 66 filaments with a total fineness of 350 dtex and 108 filaments are woven in a plain jet weave in a water jet loom, shrink-processed with boiling water, dried at 110 ° C., warp density 59 / 2.54 cm, weft density 59 A fabric / 2.54 cm woven fabric was obtained. The properties of this fabric were evaluated and are shown in Table 1.

(Comparative Example 2)
Polyamide 66 filaments with a total fineness of 350 dtex and 108 filaments are woven in a plain jet weave in a water jet loom, shrink-processed with boiling water, dried at 110 ° C., warp density 59 / 2.54 cm, weft density 59 A fabric / 2.54 cm woven fabric was obtained. Table 1 shows the characteristics of a fabric in which a solvent-free silicone resin was applied to the woven fabric and the resin amount after drying with a knife coat was 25 g / m ² .

  In the morphology observation of the re-pellet product using the fabrics of Examples 1 to 5, the thermoplastic resin in the polyamide 66 as the continuous phase was finely dispersed in a particle size of 0.1 to 1.0 μm. As a representative example, FIG. 1 shows a photograph of a re-pellet product of the fabric produced in Example 1, in which nylon 6 resin is dispersed substantially uniformly. The strength, rigidity, elongation, and impact resistance were the same as those of the non-coated fabric of Comparative Example 1 shown in FIG. On the other hand, in the morphology observation of the re-pellet product of the fabric of Comparative Example 2 shown in FIG. 3, most of the silicone resin is 10 μm to 50 μm or more as shown in FIG. The physical properties of the molded products were particularly poor in elongation and bending strength. Table 2 shows the physical properties of the molded products of Example 1 and Comparative Examples 1 and 2.

  As is apparent from Examples 1 to 5 and Comparative Examples 1 to 3, the airbag fabric is one of the safety devices that are low in cost, improve the restraining performance of the human body, and are recyclable like a non-coated fabric. Can be provided.

  The airbag fabric of the present invention is low-cost, improves the restraining performance of the human body, and can be easily recycled as a non-coated fabric, and can be used for airbag applications, which is one of automobile safety devices. It is important to contribute to the industry.

2 is a transmission electron micrograph showing a cross-sectional structure obtained from the re-pellet product of Example 1 (magnification at the time of photographing 5000 times, scale length corresponding to 2.0 μm). 3 is a transmission electron micrograph showing a cross-sectional structure obtained from the re-pellet product of Comparative Example 1 (photograph magnification of 5000 times, scale length corresponding to 2.0 μm). 4 is an optical micrograph (magnification 40 times, scale length corresponding to 50 μm at the time of photographing) showing a cross-sectional structure obtained from the re-pellet product of Comparative Example 2.

Claims (5)

A fabric in which a thermoplastic synthetic resin is applied to at least one surface of a synthetic fiber fabric having a cover factor of 1500-2500, the thermoplastic synthetic resin being a polyamide-based resin, and a molecular weight of 100 to has a 5000 soft segment, air permeability of at 100kPa difference pressure is equal to or less than 1.0L ^/ cm 2 ^/ min, and the morphology structure of the re-pellets produced by cutting the fabric directly, the continuous phase synthesis The thermoplastic synthetic resin is substantially uniformly dispersed in the resin derived from the fiber fabric, and the dispersion average particle size of the thermoplastic synthetic resin in the resin derived from the synthetic fiber fabric is 2 μm or less. An airbag fabric. ^{2. The} airbag fabric according to claim 1, wherein the adhesion amount of the thermoplastic synthetic resin is 0.1 to 15 g / m ² in terms of mass after drying.   The airbag fabric according to any one of claims 1 and 2, wherein the elongation at break of the film preparation made of the thermoplastic synthetic resin is 300% or more. The molecular weight of the said soft segment is 300-3000, The fabric for airbags of any one of Claims 1-3 characterized by the above-mentioned. The airbag fabric according to any one of claims 1 to 3, wherein the soft segment has a molecular weight of 600 to 1500.