JP5616650B2 - Airbag base fabric, airbag comprising the same, and method for producing airbag base fabric - Google Patents

Description

  TECHNICAL FIELD The present invention relates to an airbag base fabric and an airbag that are practically used for protecting an occupant at the time of an automobile collision. More specifically, the present invention relates to a flexible, lightweight, and adhesive property suitable for side collision protection. The present invention relates to an airbag base fabric having an excellent resin coating, an airbag comprising the same, and a method for manufacturing the airbag base fabric.

  In recent years, many airbag devices have been put to practical use as vehicle occupant safety protection devices, for protecting the driver's seat and front passenger seat at the time of a frontal collision, and for protecting the chest, thighs and lower back at the time of a side collision (seat There are an increasing number of mounting parts such as built-in seats and head protection on the side of the vehicle body (mounted in the ceiling above the window).

  These safety devices (hereinafter referred to as modules) include a gas generator (hereinafter referred to as an inflator) that deploys and inflates an airbag, and a bag-type airbag that absorbs inertial energy due to the collision of an occupant and relaxes the impact. , Which consists of many components such as fastening members such as metal or resin that connect them, wiring for electric signal transmission, and a resin case that covers the upper part of the device and takes design into consideration. The total weight of the module is not small. Therefore, efforts have been made to make the module components lighter and more compact, and there is a demand for lighter airbags.

  Here, in an airbag requiring high airtightness such as for side collision protection, a coating material that provides a coating material that imparts airtightness to the surface of the base fabric, for example, a silicone resin having excellent heat resistance, etc. Is used.

  In order to reduce the weight of the coating base fabric, attempts have been made to reduce the amount of coating material applied. However, if the applied amount is reduced, the coating base fabric can be reduced in weight, but it is difficult to ensure air permeability, and the adhesiveness to the base fabric tends to be insufficient. In particular, in the specifications where the airtightness of the airbag is extremely enhanced so that sufficient occupant protection performance can be ensured even if the vehicle rolls over at the time of a side collision, a sealant (sealant) used to prevent gas from leaking from the stitched part And adhesiveness) are likely to be unstable, and in some cases, peeling may occur between the coating layer and the base fabric. Therefore, a technique for coating a resin, such as a polyurethane resin, that is more easily adhered to a base fabric than conventional silicone resins has been studied.

  For example, in Patent Document 1, as a method of manufacturing a side airbag to be deployed on the side of a vehicle window, a thermoplastic polyurethane coating layer is formed on a joint surface of an outer peripheral portion thereof, and these joint surfaces are also formed. A method has been proposed in which the coating surfaces are joined together and bonded by thermal melting. In this method, a material having a polyurethane resin layer is interposed in an airbag outer periphery stitched portion, and the resin is thermally melted to improve the airtightness of the stitched portion. However, when the melting point of the resin is low, the durability and airtightness of the outer peripheral stitching portion is likely to be insufficient, and a relatively large number of resin layers are required to bring the stitching portion into close contact with each other, thereby achieving the purpose of weight reduction. I can't.

Patent Document 2 discloses a technique for applying a mixture of polycarbonate type urethane resin and polyether type urethane resin to 3 to 10 g / m ² to provide a lightweight airbag fabric. According to this method, although the coating amount of the coating material is small and a light base fabric can be obtained, the air permeability (zero air permeability) of the conventional coating base fabric cannot be ensured. Further, since the resin layer is thin, the adhesion to the base fabric is likely to be unstable, and it is difficult to use the airbag for side collision protection for vehicle rollover.

  Furthermore, in Patent Document 3, a thermoplastic resin containing a urethane resin and having a softening point of 120 ° C. or higher is used to form a coating with an average thickness of 10 μm or less on the surface of the base fabric so as to fill the contact points between the fibers. An air bag base fabric is disclosed. This document is intended to prevent the fabric from being deflated and has low air permeability. However, the dipping method is a prerequisite for this "resin coating being formed so as to fill the contacts between fibers". The air permeability reducing effect is small, and the purpose of low air permeability cannot be achieved.

  As described above, it is currently impossible to obtain an airbag base fabric and an airbag excellent in adhesion between the base fabric and the covering material with any of the methods of the above-mentioned patent documents while being lightweight and flexible. is there.

JP-A-10-129380 JP 2001-329468 A Japanese Patent Laid-Open No. 9-240405

  The present invention is lighter and more flexible than a conventional coating base fabric used as a base fabric for airbags, has excellent adhesion between the covering material and the base fabric, and is also used as an airbag for side impact collision protection for vehicle rollover. It is an object of the present invention to provide an applicable airbag base fabric and airbag, and a method for manufacturing the airbag fabric.

  By using a polyurethane resin having a high flow start temperature as a covering material for the base fabric, the inventors have excellent adhesion to the base fabric even with a small coating amount, and improve airtightness and air permeability. It has been found that it is possible to achieve this invention.

That is, the present invention is an air bag base fabric having an aqueous polyurethane resin on at least one surface of the base fabric, wherein the aqueous polyurethane resin has a flow start temperature of 160 ° C. or higher, a 100% modulus after drying of 3 MPa or less, In a laminated fabric having a layer of the water-based polyurethane resin having an adhesion amount of 10 to 30 g / m ² and a thickness of 0.1 mm between two base fabrics, the water-based polyurethane resin is peeled from the base fabric surface. The present invention relates to an airbag base fabric having a strength of 14 N / cm or more.

  The flow start temperature of the aqueous polyurethane resin is preferably 180 ° C. or higher.

  Moreover, this invention relates to the airbag which consists of the said base fabric for airbags.

  The present invention also relates to a side collision protection airbag made of the airbag fabric.

Furthermore, the present invention is a method for producing an airbag base fabric having an aqueous polyurethane resin on at least one surface of the base fabric, the aqueous polyurethane having a flow start temperature of 160 ° C. or more and a 100% modulus after drying of 3 MPa or less. applying a resin in coating weight 10 to 30 g / m ² in the base fabric, and, seen including a step of heat treatment at flow initiation temperature or higher of the aqueous polyurethane resin, and the thickness between two base fabric The present invention relates to a method for producing a base fabric for an air bag having a peel strength between the water-based polyurethane resin and a base fabric surface of 14 N / cm or more in a laminated fabric having a layer of the water-based polyurethane resin having a thickness of 0.1 mm .

  According to the present invention, it is possible to provide a base fabric for an airbag and a method for manufacturing the same, which are lightweight and flexible and have excellent adhesion between the covering material and the base fabric. This airbag base fabric is particularly suitable for use as an airbag for side collision protection.

The airbag fabric of the present invention has an aqueous polyurethane resin on at least one surface of the fabric, the aqueous polyurethane resin has a flow start temperature of 160 ° C. or higher, a 100% modulus after drying of 3 MPa or less, and attached. In a laminated fabric having an amount of 10 to 30 g / m ² and having a layer of the aqueous polyurethane resin between two base fabrics, the peel strength between the aqueous polyurethane resin and the base fabric surface is 14 N / cm or more.

  In the present invention, an aqueous polyurethane resin is used. This is because those dissolved or dispersed in any organic solvent are not preferable from the viewpoint of the working environment. The aqueous polyurethane resin may be either a forced emulsification type or a self-emulsification type, and is present in the form of an aqueous solution, a water emulsion, an aqueous dispersion, or an aqueous suspension. Of these, those that are water-soluble or self-emulsifiable are preferred in that it is not necessary to use an emulsifier. Such a resin can be obtained by introducing a hydrophilic group such as a hydroxyl group, an ethylene oxide group, or ethylene glycol into a constituent molecule.

  The flow start temperature of the aqueous polyurethane resin used in the present invention is 160 ° C. or higher, and preferably 180 ° C. or higher. When the flow start temperature is 160 ° C. or higher, the durability and heat resistance required as a covering material for the airbag fabric can be sufficiently retained. Sex is reduced. Here, the flow start temperature refers to a temperature measured by observation with a microscope equipped with a melting point measurement unit. Specifically, when a sample set in the melting point measurement unit is heated at a rate of temperature increase of about 20 ° C./min. The temperature at which the resin starts to flow. Moreover, it is preferable that a flow start temperature is 220 degrees C or less. When it is higher than 220 ° C., the resin tends to be hard.

  Further, the polyurethane resin has a 100% modulus after drying of 3 MPa or less, and preferably 2.5 MPa or less. When the 100% modulus after drying is 3 MPa or less, flexible properties are exhibited when applied to the base fabric, but when the pressure exceeds 3 MPa, the flexible properties are hardly exhibited. Here, “after drying” refers to a state after the resin film formed into a sheet or film is thermally dried at 100 ° C. for 3 hours. The 100% modulus after drying is preferably 0.5 MPa or more. If it is less than 0.5 MPa, the flexibility of the resin is excellent, but the weather resistance, abrasion resistance and the like as the coating layer tend to be insufficient.

The base fabric for airbags of the present invention has 10 to 30 g / m ^{2 of the} aqueous polyurethane resin on at least one surface of the base fabric. It is preferable to have 15 to 25 g / m ² . When it has on both surfaces of a base fabric, it is made for the total provision amount of both surfaces to be 10-30 g / m < ² >. Even with such a small amount, by using the water-based polyurethane resin, the weight of the base fabric, the flexibility, the air permeability, the wear strength of the coated surface, and the sealing agent (sealing agent) of the stitched portion All the characteristics required as a base fabric for airbags, such as the adhesiveness to ()), can be satisfied. When the applied amount is less than 10 g / m ² , the weight of the base fabric becomes light, but the air permeability, the abrasion strength of the coated surface, the adhesion with the sealing agent, etc. are insufficient, and the applied amount is 30 g / m ^2. Beyond this, the weight of the base fabric becomes heavy and the flexibility is insufficient.

  Further, when the airbag fabric of the present invention is a laminated fabric having a layer of the water-based polyurethane resin between two fabrics, the peel strength between the polyurethane resin and the fabric surface is 14 N / cm or more. is there. The peel strength is preferably 16 N / cm or more, and more preferably 18 N / cm or more. If the peel strength is 14 N / cm or more, the adhesiveness between the base fabric and the covering material is high, and it is possible to ensure the airtightness of the stitched portion, which is an essential requirement for a side collision protection airbag for vehicle body rollover. it can. When the peel strength is less than 14 N / cm, the adhesion between the base fabric and the covering material is insufficient, and an airtight air bag cannot be obtained.

  The peel strength may be measured according to JIS K6404-5. Specifically, it can be measured as follows. First, an aqueous polyurethane resin is applied to the surface of the base fabric, and another base fabric is layered thereon and dried at 80 ° C. for 2 minutes. Then, it pressurizes and heats for 1 minute at a pressure of 98 kPa with a heating press apparatus, and obtains laminated cloth. A sample having a width of 5 cm is cut from the obtained laminated fabric, and is peeled T-shaped so that the two base fabrics are 180 degrees at a measurement speed of 100 mm / min, and the peel strength is measured. At this time, the application thickness of the resin applied to the base fabric is preferably about 0.1 mm from the viewpoint of being able to measure in a stable peeling mode, but is not particularly limited. This does not mean that the coating thickness of the aqueous polyurethane resin used in the present invention is 0.1 mm, and even if the coating thickness of the aqueous polyurethane resin is less than 0.1 mm, By applying a urethane-based resin to form a resin layer of about 0.1 mm as a whole, the measurement can be similarly performed in a stable state.

  The viscosity of the water-based polyurethane resin can be selected in an optimum range according to the solid content and the application method. Especially, it is preferable that it is 0.1-200 Pa.s at 25 degreeC. When the viscosity at 25 ° C. is lower than 0.1 Pa · s, the penetration of the resin into the base fabric tends to increase, and the obtained base fabric tends to be hard. When the viscosity exceeds 200 Pa · s, the handleability at the time of application processing is poor. Tend to be. Moreover, the solid part should just be the range which can produce and preserve | save the said aqueous polyurethane resin solution stably, It is preferable that it is 20 to 70%, and it is more preferable that it is 30 to 60%.

  The number average molecular weight can be selected according to the resin characteristics to be obtained, the difficulty of making it aqueous, the stability of the solution, and the like. Especially, it is preferable that it is 5,000 to 500,000, and it is more preferable that it is 10,000 to 400,000. If the molecular weight is less than 5,000, the resulting resin film tends to be brittle, and if it exceeds 500,000, the resin film tends to become hard.

  When the aqueous polyurethane resin solution is an aqueous dispersion or aqueous emulsion, the particle size of the resin solid form is such that the uniformity of the solution, the uniformity of the resin film properties after drying, and the like are improved. The diameter is preferably 500 nm or less, and more preferably 200 nm or less.

  Moreover, it is preferable that the breaking elongation of the film obtained from the aqueous polyurethane resin is 200 to 2000%. If the elongation at break is less than 200%, the resin film becomes hard and the toughness decreases, and it tends to be difficult to follow the behavior of the development test, etc., and if it exceeds 2000%, the viscosity of the resin film increases. The coated surfaces tend to be in close contact with each other.

  Examples of the polyol component of the aqueous polyurethane resin include polycarbonate polyol, polyether polyol, polyester polyol, and acrylic polyol. Of these, polycarbonate polyols are preferred because of their high physical properties such as heat resistance and hydrolysis resistance.

  In general, a film obtained from a polyurethane resin using a polycarbonate polyol is excellent in the physical properties such as heat resistance, but has a high modulus and tends to be hard. Therefore, in order to obtain a soft resin film having a low modulus while maintaining heat resistance, when using polycarbonate polyol, use one having a melting point of 20 ° C. or lower (hereinafter referred to as low melting point polycarbonate polyol). Is preferred. Especially, it is more preferable that it is 10 degrees C or less, and it is still more preferable that it is 0 degrees C or less. On the other hand, when the melting point exceeds 20 ° C., the modulus of the film obtained from the polyurethane resin composed thereof increases, and the flexibility tends to be inferior.

  The low melting point polycarbonate polyol generally comprises 1) reaction of polyol and chlorocarboxylic acid, 2) reaction of polyol and phosgene, 3) reaction of polyol and cyclic carbonate, 4) condensation reaction of dicarbonate compound, A compound having a low melting point may be selected from the compounds obtained by the above method.

  Examples of the polyol compound used for the low-melting-point polycarbonate polyol include diols represented by HO—R—OH, that is, fatty acid diol, alicyclic diol, aromatic diol, and the like. Among them, one kind of alkylene diol (carbon number = 2 to 6), alkylene glycol (carbon number = 2 to 6), xylylene diol, or the like in that the number of carbon atoms is small and the resulting polyurethane resin film is soft. Two or more kinds of mixtures or two or more kinds of copolymers are preferred. If necessary, a polycarbonate / polyester polyol which is a copolymer with caprolactone or the like may be used.

  What is necessary is just to select the number average molecular weight of a low melting-point polycarbonate polyol according to the resin film characteristic requested | required. Especially, it is preferable that a number average molecular weight is 500-3000, and it is more preferable that it is 800-2000. If the number average molecular weight is less than 500, the elongation of the resulting resin film tends to be low, and if it exceeds 3000, the resin film tends to be hard.

  Examples of the low melting point polycarbonate include ETERNACOLL UHC50 (product of Ube Industries, Ltd.), Duranol T5652, T5651, T4672, T4671 (product of Asahi Kasei Chemicals), Plaxel CD205 (product of Daicel Chemical), and Oxymer N112 (product of Perstorp). Commercial products such as these can also be used, but are not limited thereto.

  In addition, as a polyol component, when improvement in resin film properties such as flexibility, adhesion to a base fabric, and abrasion resistance is recognized as compared with the use of a polycarbonate polyol alone, other polyols such as Polyester polyol, polyether polyol, acrylic polyol, and the like may be used within a range not exceeding the amount of polycarbonate polyol used.

  What is necessary is just to select the polyisocyanate which comprises the water-based polyurethane resin used by this invention from what is used for a normal polyurethane resin. Among them, it is preferable to use an aliphatic or alicyclic polyisocyanate excluding aromatics in that a polyurethane resin having an appropriate modulus, higher flexibility, and excellent physical properties can be obtained. .

  Preferred polyisocyanates include, for example, methylene diisocyanate, 1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,10-decamethylene diisocyanate, aliphatic isocyanates such as lysine isocyanate, isophorone diisocyanate, 1,4 -Alicyclic isocyanates such as cyclohexylmethane diisocyanate, dicyclohexylmethane diisocyanate, hydrogenated xylylene diisocyanate, and cyclohexyl diisocyanate. Of these, 1,6-hexamethylene diisocyanate is preferable from the viewpoint of flexibility of the resulting resin film, and dicyclohexylmethane diisocyanate is preferable from the viewpoint of durability of the resin film. In addition, you may use the polyurethane prepolymer etc. which created the said diisocyanate compound and low molecular weight polyols and amines so that a terminal group might become isocyanate.

  Here, for example, when an aromatic isocyanate typified by tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate or the like is used as the polyisocyanate, the resulting resin film has a high modulus and becomes a hard film. There are many cases. Therefore, it is preferable to blend these aromatic polyisocyanates in a range that does not significantly affect the resin characteristics, for example, in a range that does not become a majority.

  The blending of the polyol component and the polyisocyanate component may be selected according to the properties of the resulting resin film, and is not particularly limited. Especially, it is preferable that it is a polyol component / polyisocyanate component = 1.5 / 1-1 / 1.5 by weight ratio. If it is outside this range, the reaction efficiency tends to decrease.

  The aqueous polyurethane resin used in the present invention may contain a compound having a carboxyl group and a hydroxyl group in the molecule (hereinafter referred to as the third component) as the third component. This third component is preferable for improving the physical properties of the resulting aqueous polyurethane resin. Further, it is preferable to further use a crosslinking agent or the like because the molecular structure of the resin can be made into a network, and physical properties such as wear of the resin film can be improved.

  Since the resulting aqueous polyurethane resin can be made anionic due to the carboxyl group present in the molecule of the third component, chemical wettability to the base fabric is enhanced, and improvement in adhesion can be expected. The number of the carboxyl groups may be one or more and is not particularly limited. Especially, it is preferable that it is 2 or more at the point from which reactivity becomes high. Further, it is preferable in terms of reactivity that a hydroxyl group is present in the molecule of the third component. The number of the hydroxyl groups may be one or two and is not particularly limited. Especially, it is preferable that it is two or more at the point which reactivity improves.

  Examples of the third component include carboxylic acid-containing materials such as dioxybenzoic acid, dioxymaleic acid, dimethylol valeric acid, dimethylol butyric acid, dimethylol butanoic acid, dimethylol pyropionic acid, and derivatives thereof, or a combination thereof. One type or two or more types of polyester polyols obtained by polymerization can be used. Of these, dimethylolpropionic acid is preferred from the viewpoint of the flexibility of the resulting resin film.

  Moreover, what is necessary is just to select the compounding quantity according to the characteristic of a resin film, and when using a crosslinking agent etc. together, it can be made the same quantity as the crosslinking agent. The amount of the third component based on 100 parts by weight of the polyol component and the polyisocyanate component is preferably 1 to 25 parts by weight, and more preferably 2 to 20 parts by weight. If the amount of the third component is less than 1 part by weight, the wettability of the resin to the base fabric is insufficient, and the adhesion tends to be low. If the amount exceeds 25 parts by weight, the resulting resin film tends to be hard.

  Furthermore, it is preferable to use a crosslinking agent as the resin compounding component of the present invention because the resin network structure is sufficient and the physical properties of the resin and the thermal properties such as thermal fluidity can be improved. The cross-linking agent may be selected from compounds used for ordinary resin cross-linking, and among them, a polycarbodiimide compound is preferable in that the resin physical properties are not hardened and the hydrolysis resistance is low. Polycarbodiimide compounds are used in polyurethane resins and polyester resins as substances having high reactivity with active hydrogen such as carboxyl groups and amino groups.

  A polycarbodiimide compound is a polymer having a carbodiimide group (—N═C═N—) in a molecule, which is prepared by a decarboxylation condensation reaction with a diisocyanate using a carbodiimidization catalyst. A monocarbodiimide compound is not suitable because it has a low reaction rate due to a small number of reactive groups, and also has reactivity with moisture and lacks stability.

  The number average molecular weight of the polycarbodiimide compound is preferably about 1000 to 5000. For example, those sold under the trade name Carbodilite (Nisshinbo Chemicals Co., Ltd.), Emafix (Daiichi Seika Kogyo Co., Ltd.), Stabaxol (Hiraizumi Yoko Co., Ltd.), AQD-2050B (Sanyu Paint Co., Ltd.), etc. From the above, one type or two or more types can be selected, but are not limited thereto.

  Moreover, it is preferable that the compounding quantity is 1-20 weight part with respect to 100 weight part of compounding quantities of a polyol component and a polyisocyanate component, and it is more preferable that it is 2-10 weight part. When the blending amount is less than 1 part by weight, the physical properties of the resin film are insufficient, and the adhesion to the base fabric tends to be lowered. When the blending amount exceeds 20 parts by weight, the modulus is increased and the flexibility is easily lost. There is a tendency.

  In addition, when preferable characteristics are obtained rather than using the aqueous polyurethane resin alone, a resin or rubber compatible with the resin, for example, an aqueous silicone resin or rubber, an aqueous halogen-containing resin or rubber, an aqueous polyamide system One or two or more aqueous resins or rubbers such as resins, aqueous polyester resins, aqueous epoxy resins, and aqueous vinyl resins, or modified resins or rubbers thereof are added in an amount of 25 parts by weight or less of the aqueous polyurethane resin. You may mix and use. Resins or rubbers other than these water-based polyurethane resins are not particularly limited, and may be any material that is usually used for airbag base fabrics. Heat resistance, wear resistance, adhesion to base fabrics, flame retardancy As long as it satisfies the properties and non-adhesiveness.

Also, the production method of the present invention is an air bag base fabric having an aqueous polyurethane resin on at least one surface of the base fabric, and has a flow start temperature of 160 ° C. or higher and a 100% modulus after drying of 3 MPa or less. A step of applying the resin to the base fabric at an adhesion amount of 10 to 30 g / m ² , and a step of performing a heat treatment at a temperature equal to or higher than the flow start temperature of the aqueous polyurethane resin.

  By performing heat treatment at a temperature equal to or higher than the flow start temperature of the used aqueous polyurethane resin, the adhesion between the base fabric and the resin film can be made stronger. This is because when the resin is heated at a temperature equal to or higher than the flow start temperature, the resin applied on the base fabric easily flows on the base fabric surface, and the resin layer is uniformly rearranged. This is because it is considered that the wettability to the surface is improved and the adhesion is improved. When heat treatment is performed at a temperature lower than the flow start temperature, the adhesion becomes unstable and the peel strength also decreases.

  The temperature of heat treatment should just be more than a flow start temperature. The temperature is preferably in the range of 5 to 50 ° C. higher than the flow start temperature, and may be appropriately selected from the performance of the heat treatment apparatus, the obtained base fabric characteristics, and the like. When the temperature is higher than 50 ° C., the flow of the resin increases and penetrates into the inside of the base fabric, and conversely, the flexibility and air permeability of the base fabric tend to be impaired.

  The heating time above the flow starting temperature depends on the heat treatment temperature, taking into account the physical characteristics of the water-based polyurethane resin obtained, the adhesion between the resin and the base fabric, the physical characteristics of the airbag base fabric, etc. It only has to be selected. The heating time can be, for example, between 30 seconds and 3 minutes, and is preferably 1 to 2 minutes.

  The aqueous polyurethane resin is applied to the surface of the base fabric by various methods to be described later. The applied resin component only needs to be present on at least one surface of the base fabric, and intervenes at the intersection of the fiber yarn constituting the base fabric and its gap, and the gap of the single yarn of the fiber yarn. You may let them.

  Examples of methods for applying water-based polyurethane resin include 1) coating methods (knives, blades, kisses, reverses, commas, slot dies, lips, etc.), 2) dipping methods, 3) printing methods (screens, rolls, rotary, gravure, etc.) 4) transfer method (transfer), 5) laminating method, 6) spraying / injecting method and the like. Among these, the coating method is preferable because the setting range of the application amount is wide.

  In addition to the main resin or rubber material, the resin includes various additives or auxiliaries usually used for improving processability, adhesion to a base fabric, surface characteristics or durability, for example, Cross-linking agent, adhesion promoter, reaction accelerator, reaction retarder, heat stabilizer, antioxidant, light stabilizer, anti-aging agent, lubricant, smoothing agent, wetting agent, anti-blocking agent, pigment, water repellent, You may select and mix 1 type (s) or 2 or more types, such as oil repellent, masking agents, such as a titanium oxide, a gloss imparting agent, a flame retardant, a flame retardant, and a plasticizer.

  The properties of the polyurethane resin may be appropriately selected from liquids such as water-emulsified type and water-soluble type according to the application amount, application method, processability and stability of the material, required properties, etc. Depending on the case, solids such as powders, beads, thin films, and films, or non-solvent liquids containing only a resin component may be applied.

  In addition, various pretreatment agents for improving adhesion to the base fabric, adhesion improvers, and the like may be added to the resin, or pretreatment such as primer treatment may be applied to the surface of the base fabric in advance. Good. Furthermore, in order to improve physical properties or to impart heat resistance, anti-aging properties, heat resistance, etc., after applying the resin to the base fabric, drying, crosslinking, vulcanization, etc. are performed with hot air treatment, pressure heat treatment, high heat treatment, etc. You may carry out by energy processing (a high frequency, an electron beam, an ultraviolet-ray, etc.) etc.

  The base fabric used in the present invention may be any material that satisfies the required performance, such as a woven fabric, a knitted fabric, a braided fabric, a nonwoven fabric, a sheet-like material, a net-like material, or a composite or laminate thereof.

  When the base fabric is a woven fabric, the cover factor, which is an index indicating the denseness of the woven structure, is preferably 750 or more, and more preferably 800 or more. In the case where fiber yarns having different finenesses are used for the warp and the weft, the cover factor is calculated for each fineness of the warp and the weft, and the total is obtained.

The cover factor (CF) here is determined by the product of the woven density N (w / cm) and the square root of the thickness D (dtex) of the warp and weft of the fabric, and is represented by the following equation: .
CF = Nw × √Dw + Nf × √Df
Here, Nw and Nf are the weave density of warps and wefts (lines / cm)
Dw and Df are warp and weft thickness (dtex)

  The woven fabric is not particularly limited, such as a plain weave, an oblique weave (basket weave), a lattice weave (ripstop weave), a twill weave, a knot weave, a tangle weave, a pattern weave, or a combination thereof, or a continuous or intermittent composite structure. Of these, plain weaving is preferable in that the woven structure is dense and the warp and weft directions of physical properties are small. In addition to the two axes of warp and weft, if necessary, a multi-axis design such as three axes and four axes including 60 degrees and 45 degrees obliquely may be used, and the arrangement of the threads in that case is the original warp or weft A similar sequence may be followed.

  The production of the woven fabric may be appropriately selected from various looms used for weaving ordinary industrial woven fabrics, for example, selected from shuttle loom, water jet loom, air jet loom, rapier loom, projectile loom, etc. May be used.

  When the base fabric is knitted fabric, warp knitting such as single tricot knitting, single cord knitting, single atlas knitting, weft insertion type warp knitting in which weft is inserted into normal warp knitting, flat knitting, rubber knitting, pearl knitting, etc. Knitting structures such as the weft knitting, or the like consisting of a double structure or the like.

  Moreover, when the said base fabric is a nonwoven fabric, what was manufactured by the chemical bond method, the thermal bond method, the needle punch method, the spunlace method, the stitch bond method, the melt blow method, the papermaking method etc. is mention | raise | lifted.

  What is necessary is just to select suitably the fineness of the fiber yarn which comprises the base fabric used by this invention from what is used for industrial use. Especially, it is preferable that it is 200-1000 dtex, and it is more preferable that it is 250-700 dtex. If it is less than 200 dtex, the strength required for the airbag tends to be difficult to obtain, and if it is thicker than 1000 dtex, the weight of the base fabric and the thickness of the base fabric may increase, and the air bag may have poor storage performance.

  Moreover, the single yarn fineness of the said fiber yarn should just exist in the range of 0.5-6 dtex, and it is more preferable that it is 0.5-4 dtex. By reducing the single yarn fineness, the air permeability of the fabric is lowered, the flexibility is improved, and the folding property of the airbag is improved. Furthermore, the cross-sectional shape of the single yarn may be circular, elliptical, flat, polygonal, petal-shaped, hollow, or other irregular shapes, as long as it does not interfere with the spinning of the yarn and the production of the fabric, and the physical properties of the resulting fabric. What is necessary is just to select suitably. Further, the strength of the fiber yarn is preferably 5.4 cN / dtex or more, more preferably 8 cN / dtex or more, and further preferably 9 cN / dtex or more.

The base fabric preferably has a basis weight of 190 g / m ² or less and a tensile strength of 650 N / cm or more. If the basis weight and tensile strength are in this range, the fabric can be used as a light and excellent physical property material. . The basis weight here refers to the weight of the base fabric in an unprocessed state before applying the water-based polyurethane resin.

  The fiber yarn constituting the base fabric is not particularly limited, such as natural fiber, chemical fiber, and inorganic fiber. For example, Nylon 6, Nylon 66, Nylon 46, Nylon 610, Nylon 612, etc. alone or a copolymer thereof (including a terpolymer), an aliphatic polyamide fiber obtained by mixing, nylon 6T, nylon 6I, nylon A composite copolymer of an aliphatic amine and an aromatic carboxylic acid represented by 9T, such as polyamide fiber, polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, or a copolymer or a mixture thereof. Polyester fiber, Ultra high molecular weight polyolefin fiber, Chlorinated fiber such as vinylidene and polyvinyl chloride, Fluorinated fiber represented by polytetrafluoroethylene, Polyacetal fiber, Polysulfone fiber, Polyphenylene sulfide Fiber (PSS), polyetheretherketone fiber (PEEK), wholly aromatic polyamide fiber, wholly aromatic polyester fiber, polyimide fiber, polyetherimide fiber, polyparaphenylenebenzbisoxazole fiber ( PBO), vinylon fibers, acrylic fibers, cellulose fibers such as cotton, hemp and kenaf fibers, natural fibers such as silk and wool, polylactic acid, biodegradable fibers represented by oxalic acid, silicon carbide fibers, One type or two or more types can be selected from alumina fiber, glass fiber, carbon fiber, steel fiber, and the like. Among these, synthetic long fibers (filaments) are preferable because they are versatile and have excellent applicability to fabric manufacturing processes and excellent fabric properties. Among these, nylon 66 fibers are preferable in terms of physical properties, durability, heat resistance, and the like, and polyester fibers and nylon 6 fibers are preferable from the viewpoint of recycling.

  For the fiber yarn, various additives usually used for improving spinnability, processability, durability, etc., such as spinning oil agent, heat-resistant stabilizer, antioxidant, light-resistant stabilizer, ultraviolet absorber. , Anti-aging agents, lubricants, smoothing agents, pigments, water repellents, oil repellents, masking agents such as titanium oxide, gloss imparting agents, flame retardants, plasticizers and the like may be used. .

  The present invention also relates to an airbag made of the airbag fabric, particularly a side collision protection airbag. The airbag of the present invention is obtained by joining the outer periphery of one or more body panels obtained by cutting from the airbag base fabric, the body panel and various parts, and various parts. This joining may be performed by any method such as sewing, adhesion, and welding. In the case of sewing, it can be performed according to sewing specifications applied to a normal airbag, such as main stitching, double chain stitching, one-sided stitching, over stitching, safety stitching, staggered stitching, and flat stitching. The thickness of the sewing thread is preferably 30th (equivalent to 470 dtex) to 0th (equivalent to 2800 dtex), and the number of stitches is preferably 2 to 10 stitches / cm. When a plurality of stitch lines are required, the distance between the stitch lines may be about 2 to 10 mm, and may be performed once by a multi-needle type sewing machine or by a plurality of times of sewing by a single needle sewing machine.

  What is necessary is just to select a sewing thread | yarn suitably from what is generally called a synthetic fiber sewing thread | yarn, and what is used as an industrial sewing thread | yarn. For example, polyamide fibers such as nylon 6, nylon 66, nylon 46, polymer polyolefin fibers, fluorine-containing fibers, vinylon fibers, aromatic polyamides, PBO fibers, PPS fibers, carbon fibers, glass fibers And spun yarns, filament-twisted yarns, filament piece twisted yarns, and filament resin processed yarns.

  When joining is by adhesion or welding, the joining method may be selected according to the required strength of the stitched portion. For adhesion, for example, polyurethane-based, polyamide-based, polyester-based, epoxy-based, acrylic-based, vinyl acetate-based, cyanoacrylate-based, phenol- or resorcin-based, halogen-containing resin-based adhesives or rubber-based adhesives are used. be able to. In the case of welding, it is possible to superimpose only the base fabrics at the stitching target part and weld them with a high energy welding machine such as high frequency or ultrasonic wave. At this time, welding is performed with a hot melt material, for example, a hot melt resin such as polyurethane, polyamide, or polyester, or a reactive hot melt resin such as polyurethane or polyolefin, between the base fabrics. By doing so, damage to the base fabric can be reduced.

  Depending on the characteristics of the inflator used, the air bag of the present invention may be provided with a heat-resistant protective cloth or a mechanical reinforcing cloth on the surface of the body panel or auxiliary panel around the mounting opening of the inflator or the periphery of the gas ejection hole as necessary. May be. These protective cloths and reinforcing cloths are parts that are cut from the base fabric used for the main body panel, parts that are cut from a high weight base cloth using the same high-density yarn made of the same material as the main body panel, and the base cloth itself is heat resistant. Materials, for example, parts cut from a base fabric made of a heat-resistant fiber material such as wholly aromatic polyamide fiber, wholly aromatic polyester fiber, PBO fiber, polyimide fiber, and fluorine-containing fiber may be used. However, it may be one sheet or a plurality of sheets depending on required heat resistance and reinforcing effect.

  The specification, shape, capacity, and the like of the airbag of the present invention may be selected according to the site to be placed, application, storage space, occupant impact absorption performance, inflator output, and the like.

  In addition, in order to absorb energy when the occupant comes into contact with the airbag, one or a plurality of exhaust holes, for example, a circular hole having a diameter of 10 mm to 80 mm or an area corresponding thereto, or a slit corresponding to these exhaust performances A membrane, a valve, or the like may be provided. Reinforcing parts may be used around the exhaust hole to suppress deformation due to hot gas exhaust. Furthermore, it is preferable to provide a shape-control hanging strap inside the bag in order to suppress the protrusion to the occupant side at the initial stage of inflation of the airbag or to control the thickness of the airbag body inflation portion. Further, a gas flow path adjusting part for controlling a gas flow path ejected from the inflator inside the bag, and a belt-like part called a flap outside the bag may be provided to control the inflated shape of the airbag body.

  Folding when storing the airbag is also a folding screen that is symmetrical left and right and vertically from the center as in the case of a driver's seat, or multi-axis folding that compresses in multiple directions from the outer periphery of the airbag toward the center. Folding may be performed by such roll folding, bellows folding, folding screen-like zigzag folding, or a combination thereof, or alligator folding such as a side bag with a built-in seat.

  The airbag of the present invention includes various occupant protection bags, for example, front and rear side collision protection for driver and passenger seats, side collision protection side bags, and rear seat protection (airbelt bag body, equipped between passengers). Headrest bags for rear-end collision protection, knee bags and foot bags for leg and ankle protection, mini bags for infant protection (child seat), pedestrian protection, passenger cars, commercial vehicles, buses, etc.・ In addition to trucks, motorcycles, etc., as long as they are functionally satisfactory, they can be used for various purposes such as ships, trains / trains, airplanes, helicopters, amusement park playground equipment, emergency equipment . Especially, it can be conveniently used as an airbag for side collision protection which requires especially high airtightness.

EXAMPLES Hereinafter, the present invention will be described more specifically based on examples. In addition, the method of performance evaluation of the base fabric for airbags and an airbag performed in the Example is shown below.

(1) 100% Modulus of Resin Film A water-based polyurethane resin solution is poured into a frame provided on a glass plate and dried at 110 ° C. for 3 hours to form a resin film, and 100 by a method defined in JIS K-7311. The% modulus was determined.

(2) Elongation at break of resin film The elongation at break of the aqueous polyurethane resin film prepared according to the above (1) was determined by the method defined in JIS K-7311.

(3) Flow start temperature of resin coating Using a piece of aqueous polyurethane resin coating prepared according to (1) above, using an optical microscope equipped with a melting point measurement unit (Japan Tech product), the temperature rising rate was about 20 ° C. The flow start temperature of the resin was measured when heated at / min.

(4) Basis weight and application amount The weight per unit area of the base fabric before and after application of the resin composition was determined by the method defined in JIS L-1096 method 8.4.2. The coating amount was determined from the difference in the weight of the base fabric before and after coating.

(5) Air permeability of base fabric The air permeability was evaluated according to 8.27.1A method (Fragile method) of JIS L-1096, and the average value of N = 3 was defined as air permeability. In addition to the initial product, the evaluation was performed on a durable product heat-treated at 120 ° C. for 250 hours.

(6) Peel strength An aqueous polyurethane resin was applied to the surface of one base fabric so that the thickness after drying was approximately 0.1 mm in terms of solid content. Another base fabric was layered thereon, dried at 80 ° C. for 2 minutes, and then heated under pressure at a pressure of 98 kPa for 1 minute in a heating press set to each temperature. A sample having a width of 5 cm was cut from the prepared laminated fabric, and the peel strength was measured by peeling the T-shape so that the two base fabrics were 180 degrees at a measurement speed of 100 mm / min. The average value of N = 3 was defined as the peel strength.

(7) Folding thickness of the base fabric A 20cm square base fabric is folded once in the vertical and horizontal directions and folded into a state where four base fabrics are folded, and a 10 mm thick and 10 cm square glass plate is placed on top of it. I put it. Further, a 500 g weight was loaded, and the thickness of the base fabric after 1 minute was measured. This is expressed as a relative value when Example 1 is 100.

(8) Airtightness test of airbag From the prepared base fabric, 2 pieces of flask-shaped parts having an outer diameter of 540 mm and a circular outer edge provided with an opening having a height of 100 mm and a width of 50 mm as a gas inlet Cut into pieces. Here, the opening was provided at a position where the center line coincides with the yarn axis direction of the base fabric. Apply urethane-based reactive hot melt resin (Nippon NSC Corp., Bond Master 170-7254) to the stitches on the outer periphery of the resin surface of one of the two base fabrics, and then the resin of the other base fabric. The surfaces were overlapped and pressure-bonded so that the thickness of the hot melt resin was 0.6 mm. The shape of the application part was a circular shape (sewing allowance 20 mm) with a width of 10 mm centered on 500 mm. Further, a central joint portion having a width of 10 mm and a length of 100 mm was disposed at a central position which is a circular central portion and is just below the opening and parallel to the gas flow. The hot melt resin was used for bonding at the center bonding portion, and pressure bonding was similarly performed so that the thickness became 0.6 mm. The hot melt resin was also applied to the periphery of the gas injection opening along the outer edge of the cut piece so that the seam allowance was 20 mm. After application, the hot melt resin was cured by allowing it to stand at room temperature for 24 hours. Subsequently, the hot melt resin was applied to the outer periphery and the center joint portion by using 1400 dtex (equivalent to the 5th thread) of nylon 66 fiber for both the upper thread and the lower thread in a row of 35 stitches / cm and main stitching. The center of the part was sewn. Attach the opening of the obtained airbag to an airbag burst tester, rapidly inject high-pressure nitrogen gas to an internal pressure of 100 kP, stop the supply of gas, destroy the sealing portion of the stitched portion, and the airbag The airtightness (internal pressure retention) was observed.

  In addition, since a larger stress is applied to the central joint portion than the peripheral stitched portion during expansion, the base fabric and the polyurethane covering the base fabric are checked by checking whether or not peeling occurs at the central joint portion. Adhesion with the resin can be confirmed. That is, when no peeling occurs at the central joint, it is considered that no peeling occurs at the outer peripheral sewing portion, and it can be assumed that there is no gas leak.

  Airtightness is evaluated on the basis of the rate at which the internal pressure of the airbag is reduced, and airtightness is poor when the internal pressure drops quickly and deflates quickly. It's expensive.

Hereinafter, the composition of the polyurethane resin solution used in Examples and Comparative Examples is shown.
(Resin 1)
100 parts (polycarbonate diol / polyisocyanate = 100) of polycarbonate polyol (melting point -5 ° C., manufactured by Asahi Kasei Chemicals Corporation, polycarbonate diol, trade name Duranol T5651, molecular weight 1000) and alicyclic polyisocyanate (dicyclohexylmethane diisocyanate) / 110), 8 parts of dimethylolpropionic acid, polycarbodiimide (manufactured by Nisshinbo Chemicals, trade name Carbodilite SV-02, molecular weight 1720), an aqueous polyurethane resin (solid content 35%, solution viscosity (25 ° C.)) 20 Pa · s, molecular weight 18,000, aqueous solution). Flow start temperature of the resin film after drying: 180 ° C. Elongation at break: 1330%.

(Resin 2)
In the resin 1, an aqueous polyurethane containing no carbodiimide compound as a crosslinking agent as a polymerization component (solid content 35%, solution viscosity (25 ° C.) 18 Pa · s, molecular weight 13,000, aqueous solution). Flow start temperature of the resin film after drying: 125 ° C. Elongation at break: 1520%.

(Resin 3)
PASCOE JK-831N (manufactured by Meisei Chemical Co., Ltd., polyurethane resin solution consisting of polycarbonate polyol and aliphatic polyisocyanate having a melting point of 45 ° C.), aqueous polyurethane resin solution (solid solution) obtained from 5 parts of carboxymethyl cellulose (thickener) 30% mold content, solution viscosity (25 ° C.) 14 Pa · s, molecular weight 10,000, aqueous solution). Flow start temperature of the resin film after drying: 140 ° C. Elongation at break: 1010%.

Example 1
Both warp and weft are made of nylon 66 fiber 470 dtex / 136 f (strength 8.6 cN / dtex), plain fabric is prepared, scoured and set, and the warp and weft density are both 18 / cm A base fabric was obtained. Next, resin 1 was applied to one side of the base fabric by a knife coating method so as to give an applied amount of 20 g / m ² , followed by drying and heat treatment at 190 ° C. for 1 minute. I got a cloth. The tensile strength of the obtained base fabric was 675 N / cm. The weight was 175 g / m ² before applying the resin (weight) and 195 g / m ² after applying the resin.

  Performance evaluation was performed using this base fabric. As shown in Table 1, the 100% modulus of the resin coating was small and soft. Moreover, as shown in Table 2, the obtained airbag base fabric was lightweight, and the airbag obtained from the airbag had no air separation and showed high airtightness.

Comparative Example 1
An airbag base fabric and an airbag were prepared in the same manner as in Example 1 except that the amount of resin applied was 5 g / m ² . The weight of the base fabric after application of the resin was 180 g / m ² . As shown in Table 2, although the weight of the base fabric and the folding thickness were small, the air permeability was lowered because the amount of the resin coating applied was small. In the airtightness test, resin peeling occurred at the center joint, and airtightness was insufficient.

Comparative Example 2
A base fabric for an airbag and an airbag were prepared in the same manner as in Example 1 except that the resin 2 was used as the resin and the heating temperature after application of the resin was 150 ° C. As shown in Table 1, since the resin film has a small 100% modulus and becomes a soft resin, the foldability of the obtained base fabric is slightly improved. However, even if the heating temperature after application of the resin is higher than the flow start temperature of the resin, the flow start temperature itself is low, so that the air permeability after the durability test is poor. Furthermore, the peel strength between the base fabric and the resin is slightly lowered, and the airtightness as an airbag is not high.

Comparative Example 3
An airbag base fabric and an airbag were prepared in the same manner as in Example 1 except that the resin 3 was used as the resin and the heating temperature after application of the resin was 150 ° C. Since the 100% modulus of the resin is high, the folding thickness of the airbag fabric is increased.

Comparative Example 4
An airbag base fabric and an airbag were produced in the same manner as in Example 1 except that the heat treatment temperature after application of the resin was 150 ° C. Since the heat treatment temperature was lower than the resin flow start temperature, the peel strength between the resin and the base fabric was not sufficient, and in the airtightness test, the resin peeled off at the center joint, resulting in insufficient airtightness.

Comparative Example 5
An airbag base fabric and an airbag were prepared in the same manner as in Example 1 except that the amount of resin applied was 35 g / m ² . There was no problem with the base fabric's air permeability, peel strength, and air bag's air tightness, but because the amount of resin applied was large, the folding thickness of the base fabric would increase, and a lightweight, compact airbag could be obtained. could not.

Claims (5)

An air bag base fabric having an aqueous polyurethane resin on at least one surface of the base fabric, wherein the aqueous polyurethane resin has a flow start temperature of 160 ° C. or higher, a 100% modulus after drying of 3 MPa or less, and an adhesion amount of 10 to 30 g. / M ² , and in a laminated fabric having a layer of the water-based polyurethane resin having a thickness of 0.1 mm between two base fabrics, the peel strength between the water-based polyurethane resin and the base fabric surface is 14 N / cm or more A base fabric for an airbag. The base fabric for an air bag according to claim 1, wherein the flow start temperature of the aqueous polyurethane resin is 180 ° C or higher. An airbag comprising the airbag fabric according to claim 1 or 2. An airbag for side collision protection comprising the airbag fabric according to claim 1 or 2. A method for producing a base fabric for an air bag having an aqueous polyurethane resin on at least one surface of the base fabric, wherein an aqueous polyurethane resin having a flow start temperature of 160 ° C. or higher and a 100% modulus after drying of 3 MPa or less is applied in an amount of 10 to 10. step of applying the base fabric at 30 g / m ^2, and, seen including a step of heat treatment at flow initiation temperature or higher of the aqueous polyurethane resin, and a thickness of 0.1mm between two base fabric A method for producing a base fabric for an air bag , wherein a peel strength between the aqueous polyurethane resin and a base fabric surface is 14 N / cm or more in a laminated fabric having a layer of the aqueous polyurethane resin .