阅读说明：本技术 安全气囊用非涂层基布、安全气囊和安全气囊用非涂层基布的制造方法 (Uncoated base fabric for airbag, and method for producing uncoated base fabric for airbag ) 是由 保坂太纪 于 2019-08-27 设计创作，主要内容包括：一种安全气囊用非涂层基布,其特征在于,由聚酰胺纤维制成,沿基布纬纱方向每20cm测定一次而得到的(A)～(C)的透气度的CV值满足下述要件：(A)基于ASTM D6476法测得的动态透气度的变异系数即CV值为6.0％以下,(B)基于ASTM D3886法测得的500Pa压差下透气度的CV值为10.0％以下,(C)基于JIS L 1096测得的20KPa压差下透气度的CV值为10.0％以下。(A non-coated base fabric for an airbag, characterized in that CV values of air permeabilities (A) to (C) made of polyamide fibers and measured every 20cm in the weft direction of the base fabric satisfy the following requirements: (A) a CV value, which is a coefficient of variation of dynamic air permeability measured by ASTM D6476, of 6.0% or less, (B) a CV value of air permeability measured by ASTM D3886 at 500Pa pressure difference of 10.0% or less, and (C) a CV value of air permeability measured by JIS L1096 at 20KPa pressure difference of 10.0% or less.)

1. A non-coated base fabric for an airbag, characterized in that CV values of air permeabilities (A) to (C) made of polyamide fibers and measured every 20cm in the weft direction of the base fabric satisfy the following requirements:

(A) the CV value, which is the coefficient of variation of dynamic air permeability measured by ASTM D6476, is 6.0% or less,

(B) a CV value of air permeability at 500Pa pressure difference of 10.0% or less as measured by ASTM D3886, an

(C) The CV value of air permeability at a pressure difference of 20KPa measured in accordance with JIS L1096 is 10.0% or less.

2. The uncoated base fabric for an airbag according to claim 1, wherein a CV value of tensile strength measured every 20cm in a weft direction of the base fabric is 1.5% or less, and a CV value of tear strength is 3.0% or less.

3. A method for producing the uncoated base fabric for an airbag according to claim 1 or 2, comprising a heat-setting step and a step of adjusting the surface temperature of the base fabric before the heat-setting step,

the heat setting step is performed after the surface temperature of the base fabric is adjusted to 40 to 70 ℃.

4. An airbag produced by sewing the uncoated base fabric for an airbag according to any one of claims 1 to 3.

Technical Field

The present invention relates to a non-coated base fabric for an airbag, and a method for producing a non-coated base fabric for an airbag. More specifically, the present invention relates to a non-coated base fabric for an airbag having uniform air permeability in the weft direction of the base fabric, an airbag sewn from the non-coated base fabric for an airbag, and a method for producing the non-coated base fabric for an airbag.

Background

In recent years, various airbags have been installed in vehicles in order to ensure the safety of occupants at the time of vehicle collision. Examples of the various airbags include a driver protection airbag, a passenger protection airbag, a knee protection airbag, a chest protection airbag built in a seat base, a head protection airbag mounted in a ceiling above a window, and the like. An airbag for protecting a driver or a passenger mainly using a non-coated base fabric has vent holes (vent holes) for adjusting the internal pressure of the airbag to adjust and maintain the internal pressure appropriately. However, when the air permeability of the uncoated base fabric is not uniform, the air release holes may not be able to adjust and maintain a predetermined internal pressure. Therefore, the base fabric for an airbag is required to have uniform air permeability.

Further, the airbag is imparted with high-pressure air at high speed when deployed. Therefore, the air bag is required to have uniform air permeability not only at low pressure and constant pressure which have been conventionally required but also in a form in which the form of the base fabric is changed, such as dynamic air permeability and high pressure air permeability.

Further, the airbag is required to have a property (rupture resistance) that it does not rupture due to an impact or an internal pressure of the bag when the airbag is deployed. Therefore, the base fabric is required to have excellent mechanical properties (tensile strength, tear strength, etc.) in order to obtain an airbag having excellent rupture resistance.

As a method for obtaining uniform air permeability and mechanical properties, for example, patent document 1 proposes a base fabric made of polyester filaments, which is obtained by performing a roller setting step and a tenter setting step in combination. As a means for achieving uniform air permeability and combustibility, patent document 2 proposes a finished fabric obtained by performing a roll shrinkage setting step. Further, patent document 3 proposes a method of obtaining uniform air permeability by making the crimp ratio uniform by keeping the warp tension in weaving equal in the width direction.

Documents of the prior art

Patent document

Patent document 1 Japanese patent laid-open No. H10-8344

Patent document 2 Japanese patent application laid-open No. 9-105047

Patent document 3 Japanese patent laid-open No. 2008-81873

Disclosure of Invention

The technique disclosed in patent document 1 involves a high cost because the roller setting step and the tenter setting step are carried out in combination. Further, in the technique disclosed in patent document 1, since the air permeability is made uniform by changing the surface state of the woven fabric, uniform air permeability cannot be achieved in an air permeability mode in which the surface state of the base fabric is changed, such as high-pressure air permeability and dynamic air permeability. The technique disclosed in patent document 1 is not described about uniformity of mechanical strength. Further, the technique disclosed in patent document 2 performs a shrinking process through a roller setting step. Therefore, the technique disclosed in patent document 2 is insufficient in uniformity of mechanical strength in the width direction. Further, the technique disclosed in patent document 2 cannot achieve uniform air permeability in an air permeability mode in which the surface state of the base fabric is changed, such as high-pressure air permeability and dynamic air permeability. Further, the technique disclosed in patent document 3 relates to a base fabric woven at a high density, and is not suitable for a base fabric woven at a low density. Further, patent document 3 does not mention uniformity of mechanical strength.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to provide a non-coated base fabric for an airbag having excellent uniformity of air permeability and uniformity of mechanical properties, an airbag sewn from the non-coated base fabric for an airbag, and a method for producing the non-coated base fabric for an airbag.

The uncoated base fabric for an airbag of the present invention for solving the above problems is characterized in that CV values (i.e., coefficient of variation) of air permeabilities (a) to (C) made of polyamide fibers and measured every 20cm in the weft direction of the base fabric satisfy the following requirements,

(A) a CV value of dynamic air permeability measured by ASTM D6476 of 6.0% or less,

(B) a CV value of air permeability at 500Pa pressure difference of 10.0% or less as measured by ASTM D3886 method,

(C) the CV value of air permeability at a pressure difference of 20KPa measured in accordance with JIS L1096 is 10.0% or less.

The method for producing an uncoated base fabric for an airbag according to the present invention for solving the above problems includes a heat-setting step and a step of adjusting the surface temperature of the base fabric before the heat-setting step, wherein the heat-setting step is performed after the surface temperature of the base fabric is adjusted to 40 to 70 ℃.

An airbag according to the present invention, which solves the above problems, is an airbag sewn from the uncoated base fabric for an airbag.

Detailed Description

[ uncoated base cloth for air bag ]

The uncoated base fabric for an airbag according to an embodiment of the present invention (hereinafter, also simply referred to as a base fabric) is a woven fabric woven from polyamide fibers. The CV values (coefficient of variation) of the air permeabilities of (a) to (C) measured every 20cm in the weft direction of the base fabric of the present embodiment satisfy the following requirements.

(A) A CV value of dynamic air permeability measured by ASTM D6476 of 6.0% or less,

(B) a CV value of air permeability at 500Pa pressure difference of 10.0% or less as measured by ASTM D3886 method,

(C) the CV value of air permeability at a pressure difference of 20KPa measured in accordance with JIS L1096 is 10.0% or less.

(Fabric woven from Polyamide fibers)

Examples of the polyamide fibers include fibers formed from nylon 6, nylon 1,2, nylon 4,6, a copolymerized polyamide of nylon 6 and nylon 6, a copolymerized polyamide obtained by copolymerizing nylon 6 with a polyalkylene glycol, a dicarboxylic acid, an amine, or the like. The polyamide fiber is preferably a fiber made of nylon 6 or nylon 6,6 in view of excellent impact resistance of the airbag obtained.

In the present embodiment, the total fineness of the polyamide fibers is not particularly limited. Examples include: the total fineness of the polyamide fibers is preferably 235dtex or more, more preferably 280dtex or more. The total fineness of the polyamide fibers is preferably 940dtex or less, and more preferably 700dtex or less. When the total fineness of the polyamide fibers is within the above range, the mechanical properties (tensile strength, tear strength, etc.) required for the resulting airbag can be easily obtained. Further, the obtained base fabric is excellent in lightweight and compactness. Further, the total fineness of the polyamide fibers can be calculated by the method of JIS L1013 (1999) 8.3.1A.

The single fiber fineness of the polyamide fiber is not particularly limited. Examples include: the single fiber fineness of the polyamide fiber is preferably 1dtex or more, more preferably 1.5dtex or more, and further preferably 2dtex or more. The single fiber fineness of the polyamide fiber is preferably 8dtex or less, and more preferably 7dtex or less. By setting the single fiber fineness of the polyamide fiber to 1dtex or more, breakage of single fibers during production can be further suppressed, and production is facilitated. Further, by setting the single fiber fineness of the polyamide fiber to 8dtex or less, the flexibility of the obtained warp and weft is improved. The single fiber fineness of the polyamide fiber can be calculated by dividing the total fineness by the number of filaments. Further, the number of filaments can be calculated based on the method of JIS L1013 (1999)8.4.

The cross-sectional shape of the single fiber of the polyamide fiber is not particularly limited. For example, the cross-sectional shape of the single fiber may be circular, and may be various non-circular shapes such as Y-shape, V-shape, flat shape, and the like, and may be a shape having a hollow portion. Among them, the cross-sectional shape of the single fiber is preferably circular from the viewpoint of the yarn formability.

Returning to the explanation of the whole polyamide fiber, the tensile strength of the polyamide fiber of the present embodiment is preferably 8.0cN/dtex or more, and more preferably 8.4cN/dex or more. When the tensile strength of the polyamide fiber is within the above range, the obtained base fabric tends to have sufficient mechanical properties (tensile strength, tear strength, etc.). The upper limit of the tensile strength is not particularly limited. Further, the tensile strength of the polyamide fiber can be calculated by measurement under conditions of constant elongation shown in JIS L1013 (1999) standard 8.5.1 tests.

The elongation of the polyamide fiber is preferably 20% or more, and more preferably 21% or more. The elongation of the polyamide fiber is preferably 25% or less, and more preferably 24% or less. When the elongation of the polyamide fiber is within the above range, the obtained fabric is excellent in toughness and breaking work. Further, the polyamide fiber exhibiting an elongation within the above range is improved in the yarn formability and the weavability. The elongation of the polyamide fiber can be calculated based on the elongation at the point corresponding to the point showing the maximum strength in the S-S curve obtained when the tensile strength is calculated. Additives such as heat stabilizers, antioxidants, light stabilizers, smoothing agents, antistatic agents, plasticizers, thickeners, pigments, and flame retardants may be appropriately added to the polyamide fibers in order to improve the productivity in the spinning step, the stretching step, and the processing step and the properties of the resulting fabric.

Returning to the description of the entire base fabric, the base fabric of the present embodiment has a CV value of dynamic air permeability measured by ASTM D6476 of 6.0% or less, a CV value of air permeability measured by ASTM D3886 at 500Pa differential pressure of 10.0% or less, and a CV value of air permeability measured at 20KPa differential pressure of 10.0% or less, measured every 20cm in the weft direction of the base fabric. If the respective air permeabilities are higher than the above respective CV values, the internal pressure performance tends to be uneven at the cut position of the base fabric used for the airbag. In addition, the 3 types of air permeabilities of the base fabric of the present embodiment have high uniformity. In the case where the air permeability is not uniform, the internal pressure performance may be non-uniform depending on the magnitude of the impact of the airbag, the type of inflator, the acceleration of the driver, and the like. Further, the CV value can be generally measured and calculated over the entire width direction of the base fabric. When the width of the base fabric is small, the number of measurement points may be at least 5 or more.

The dynamic air permeability of the base fabric of the present embodiment measured by the ASTM D6476 method is preferably 700mm/s or less, more preferably 600mm/s or less. When the dynamic air permeability is in the above range, the necessary internal pressure performance of the airbag can be easily obtained.

This implementationThe base fabric of the embodiment preferably has an air permeability of 3.0L/dm at 500Pa pressure difference measured by ASTM D3886 method²Less than min, more preferably 2.5L/dm²Less than min. When the air permeability under a pressure difference of 500Pa is within the above range, the necessary internal pressure performance of the airbag can be easily obtained.

The air permeability of the base fabric of the present embodiment is preferably 1.5L/cm at a pressure difference of 20KPa measured according to JIS L1096 (1999)²Less than min, more preferably 1.2L/dm²Less than min. When the air permeability is within the above range at a pressure difference of 20KPa, the necessary internal pressure performance of the airbag can be easily obtained.

The base fabric of the present embodiment preferably has a CV value of tensile strength of 1.5% or less, and a CV value of tear strength of 3.0% or less, measured every 20cm in the weft direction of the base fabric. By satisfying the CV values, the uneven restraining performance of the driver due to the cut position of the base fabric used for the airbag is less likely to occur. The tensile strength is a tensile strength measured in accordance with JIS K6404-3 (1999), and the tear strength is a tear strength measured in accordance with JIS K6404-4 (1999).

The tensile strength of the base fabric of the present embodiment is preferably 600N/cm or more, more preferably 625N/cm or more, and still more preferably 650N/cm or more in both the warp and weft directions. The upper limit of the tensile strength is not particularly limited. By making the tensile strength within the above range, the resulting airbag easily obtains necessary mechanical strength at the time of deployment.

The tear strength of the base fabric of the present embodiment is preferably 100N or more, and more preferably 125N or more, in both the warp and weft directions. The upper limit of the tearing strength is not particularly limited. By making the tear strength within the above range, the resulting airbag easily obtains necessary mechanical strength upon deployment.

The basis weight of the base cloth is preferably 220g/m²The lower, more preferably 215g/m²The following. By making the basis weight within the above range, the weight of the airbag obtained is appropriate and not too large. The light weight of the base fabric is directly related to the fuel consumption of the automobile. Therefore, the lower the basis weight, the better. On the other hand, the lower limit of the basis weight is preferably from the viewpoint of the required heat-resistant capacity150g/m²The above. Further, the basis of JIS L1096 (1999)8.4.2, the basis of the present invention can be used for the basis of the following claims.

The thickness of the base fabric is preferably 0.35mm or less, more preferably 0.33mm or less. In the case where the thickness of the base fabric is within the above range, it is easy to secure a space for a passenger in a vehicle in which the airbag is installed. In addition, the degree of freedom in the design of the vehicle interior can be easily improved. When the thickness exceeds 0.35mm, the compactness of the base fabric tends to be reduced.

[ air bag ]

An airbag according to an embodiment of the present invention is an airbag sewn from the base fabric (uncoated base fabric for an airbag) of the above-described embodiment. The airbag according to the present embodiment can be manufactured by a conventionally known method. That is, the airbag is manufactured by sewing a base fabric into a bag shape, and attaching accessories such as an inflator.

As described in detail in the above embodiments, the base fabric constituting the airbag is excellent in the uniformity of air permeability in the weft direction, tensile strength, and tear strength. Therefore, the airbag of the present embodiment can obtain uniform internal pressure holding performance and driver restraining performance without being affected by the cutting position of the base fabric. Therefore, the airbag is useful for protecting a driver, a passenger, a knee, a chest built in a seat base, a head mounted in a ceiling above a window, and the like.

[ method for producing uncoated base Fabric for air bags ]

A method for producing a non-coated base fabric for an airbag according to an embodiment of the present invention (hereinafter, also simply referred to as a method for producing a base fabric) is a method for producing a base fabric (a non-coated base fabric for an airbag) according to the above-described embodiment. The method for producing the base fabric includes a heat-setting step and a step (preheating step) of adjusting the surface temperature of the base fabric before the heat-setting step. The preheating step is a step of adjusting the surface temperature of the base fabric to 40-70 ℃. The other steps described below are merely examples, and may be replaced with other known steps as appropriate.

According to the present embodiment, the warp yarns are warped in association with the base fabric and set in the loom. The weft yarns are likewise arranged in the weaving machine. The loom is not particularly limited. The loom may be exemplified by a water jet loom, an air jet loom, a rapier loom, and the like. Among these, the water jet loom is preferable in terms of ease of high-speed weaving and ease of productivity improvement. Preferably, both the warp and weft yarns are of the same type of polyamide fibre. Further, it is preferable that the warp and weft yarns are woven so as to have the same weave density. In the present embodiment, the "same type of polyamide fiber" refers to a fiber having the same polymer type, total fineness, and physical properties. The phrase "the same weaving density" means that the difference between the weaving densities of the warp and weft after weaving is 1.5 or less. The weave density may be based on JIS L1096: 1999) 8.6.1.

The weaving conditions are not particularly limited. Examples include: the warp tension is preferably adjusted to 60 to 100 cN/yarn in weaving. When the warp tension is within the above range, the warp subjected to the tension becomes flat when the weft is inserted, and the air permeability can be controlled to be low. When the warp tension is 60 cN/weft or more, the warp has a suitable force for binding the weft, and a predetermined density can be easily achieved. In addition, when the warp tension is 100 cN/piece or less, low air permeability can be obtained, and the warp is not easily subjected to burr generation due to friction, so that excellent productivity can be easily maintained.

The method of adjusting the warp tension is not particularly limited. For example, the warp tension can be adjusted by adjusting the warp feeding speed of the loom, the weft driving speed, or the like. Whether or not the warp tension is in the above range can be confirmed by measuring the tension applied to each of 1 warp yarn by measuring the central portions of the warp yarn bobbin and the back roller during the operation of the loom using, for example, a tension meter.

In the method for producing a base fabric of the present embodiment, the timing of opening at the time of weaving is preferably 330 degrees or more. The opening timing is preferably 0 degree (360 degrees) or less, and more preferably 340 degrees or less. When the shedding timing is within the above range, the tension of the weft yarn during weaving is uniform, and a uniform tensile strength is easily obtained. When the opening timing is 330 degrees or more, the tension of the weft is uniform, and the variation in tensile strength is unlikely to occur. On the other hand, when the shedding timing is 0 degrees or less, the weft is sufficiently restricted, and the weaving property is excellent. In the present embodiment, the term "shedding timing" means that the reed moves 1 round trip (1 turn of the loom) by 360 degrees, and each timing is represented by 0 to 360 degrees. The timing 0 degree (360 degrees) is a timing when the reed moves to the forefront of the weaving front side.

When weaving is completed, the obtained fabric is subjected to scouring processing as needed. In the scouring process, the fabric is, for example, put into a plurality of tanks and washed with water. In this case, a scouring agent (e.g., a nonionic surfactant or an anionic surfactant) is appropriately added. The water temperature of each tank is about 40-70 ℃. This activates the scouring agent, and the oil agent, wax, and the like adhering to the woven yarn can be effectively removed.

In the method for producing a base fabric of the present embodiment, a preheating step is performed before the obtained fabric is heat-set. In the preheating step before heat setting, the surface temperature of the base fabric is preferably adjusted to 40 to 70 ℃, more preferably 42 to 69 ℃. Further, the CV value of the surface temperature in the weft direction of the base fabric is preferably 0.04% or less. In the case where the temperature of the base fabric before heat-setting is within the above range, the structure of the base fabric in the weft direction of the base fabric is uniform, and even the air permeability and the mechanical strength can be made more uniform. The preheating step before the heat-setting step is not particularly limited. The preheating process may be performed by a hot air dryer, a suction drum dryer, a non-contact dryer, or the like.

Here, the unevenness of physical properties in the weft direction is described. The unevenness in physical properties in the weft direction of the base fabric is caused by the unevenness in the structure of the base fabric, and the unevenness in the structure of the base fabric is affected by the flatness, tension, constraint, crimp ratio, and the like of the fibers constituting the base fabric. These factors determining the structure of the base fabric can be changed by performing a heat setting process in a state higher than the glass transition temperature of the fibers. Based on this technical background, it has been found that uniform air permeability can be obtained by a method such as extending the heat-setting time or raising the heat-setting temperature in the conventional processing step. However, according to this conventional method, uniform strength in the width direction cannot be obtained due to excessive heat shrinkage, and the fibers shrink due to excessive heat setting, so that a predetermined air permeability cannot be obtained. The present inventors have repeatedly conducted various tests in view of the above-described current situation, and as a result, have found that the preheating step is performed before the heat-setting step, and more uniform air permeability characteristics and mechanical characteristics can be imparted to the base fabric of the present embodiment.

After the preheating step before heat setting, the heat setting process may be performed on the base fabric whose surface temperature has been adjusted. The heat-setting temperature is not particularly limited. Examples include: the heat setting temperature is preferably 120 to 200 ℃, and the heat setting time is preferably about 30 to 40 seconds. Preferably, the tension in the warp direction at the time of heat setting is 0.1 to 0.5kg/cm, and the tension in the weft direction at the time of heat setting is 0.1 to 0.3 kg/cm. The machine used in the heat setting step is not particularly limited. Examples include: the machine used in the heat setting step is a pin tenter (ピンテンター), a clip tenter (クリップテンター), or the like, which can control the shrinkage of the base fabric in the width direction.

The base fabric obtained as described above has excellent uniformity in air permeability in the weft direction and mechanical strength. Therefore, the base fabric can realize uniform internal pressure characteristics and driver restraint performance without being affected by the cutting position, and is therefore particularly useful as a base fabric for an airbag.

The above description is directed to one embodiment of the present invention. The present invention is not limited to the above embodiments. The above embodiments mainly describe inventions having the following features.

[1] A non-coated base fabric for an air bag, characterized in that CV values of air permeabilities (A) to (C) obtained by measuring the air permeability once per 20cm in the weft direction of the base fabric and made of polyamide fibers satisfy the following requirements,

(A) a CV value of dynamic air permeability measured by ASTM D6476 of 6.0% or less,

(B) a CV value of air permeability at 500Pa pressure difference of 10.0% or less as measured by ASTM D3886 method,

(C) the CV value of air permeability at a pressure difference of 20KPa measured in accordance with JIS L1096 is 10.0% or less.

[2] The uncoated base fabric for an airbag according to [1], wherein a CV value of tensile strength measured every 20cm in a weft direction of the base fabric is 1.5% or less, and a CV value of tear strength is 3.0% or less.

[3] The method for producing the uncoated base fabric for an airbag according to [1] or [2], comprising a heat-setting step and a step of adjusting the surface temperature of the base fabric before the heat-setting step, wherein the heat-setting step is performed after the surface temperature of the base fabric is adjusted to 40 to 70 ℃.

[4] An airbag produced by sewing the uncoated base fabric for an airbag according to any one of [1] to [3].

Examples

The present invention will be described more specifically with reference to examples. The present invention is not limited to these examples. In the following examples, the respective characteristic values are calculated by the following methods.

< method for calculating characteristic value >

(Total fineness)

The total fineness was calculated by measuring the fineness in terms of a metric amount at a predetermined load of 0.045cN/dtex in accordance with JIS L1013 (1999)8.3.1A method.

(filament number)

The number of filaments was calculated based on the method of JIS L1013 (1999)8.4.

(Single fiber fineness)

Single fiber denier is calculated by dividing the total denier by the number of filaments.

(tensile Strength and elongation of filament)

The tensile strength and elongation are calculated by measurement under the conditions of constant elongation shown in the test under JIS L1013 (1999)8.5.1 standard. At this time, the jig interval was set to 25cm and the drawing speed was set to 30 cm/min using "TanzenON" (TENSILON) UCT-100 manufactured by オリエンテック. In addition, the elongation is calculated based on the elongation at the point showing the maximum strength in the S-S curve.

(weave Density)

The weaving density of each of the warp and weft yarns is based on JIS L1096: (1999) 8.6.1. Specifically, the sample was placed on a flat table, the unnatural wrinkles and tension were removed, the number of warp yarns and weft yarns in a 2.54cm interval was counted every 20cm from one end of the base fabric, and the average value of each of the warp yarns and weft yarns was calculated. The CV value was calculated by dividing the standard deviation of the data collected every 20cm by the average value and multiplying the result by 100.

(pay for your eyes)

The basis of JIS L1096: (1999)8.4.2 taking 20 cm. times.20 cm test pieces from one end of the base cloth every 20cm, measuring the masses (g) of the pieces, and converting the average value to 1m²Mass (g/m) of²) To calculate. The CV value was calculated by dividing the standard deviation of the data collected every 20cm by the average value and multiplying the result by 100.

(thickness)

The thickness was measured by using a thickness measuring machine having a circular measuring head with a diameter of 1.05cm per 20cm from one end of the base fabric by the method of JIS L1096 (1999)8.5A, and holding the base fabric under a pressure of 1.0kPa for 10 seconds to allow the thickness to sink. The CV value was calculated by dividing the standard deviation of the data collected every 20cm by the average value and multiplying the result by 100.

(surface temperature of base cloth)

The surface temperature of the base fabric was measured 5 times at 5 positions in the weft direction of the base fabric using a radiation thermometer manufactured by Fluke, and the average value thereof was calculated.

< example 1 >

(preparation of yarn)

As the warp and weft, there was prepared a synthetic fiber filament of nylon 6, which was composed of 72 filaments of 6.52dtex single fiber having a circular cross-sectional shape and a total fiber fineness of 470dtex, a tensile strength of 8.4cN/dtex, an elongation of 23.5%, and no twist.

(weaving)

The yarns were used as warp and weft yarns, and a fabric having a weaving density of 54 yarns/2.54 cm and a width of 200cm was woven by a water jet loom. At this time, the warp tension was adjusted to 94 cN/warp, the shedding timing was 340 degrees, and the loom rotation speed was 600 rpm.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried by a conventional method under the conditions described in table 1. Then, the base fabric having a surface temperature of 42 ℃ maintained by the hot air dryer was subjected to heat setting processing at 180 ℃ for 1 minute under the dimensional specifications of a width increasing rate of 0% and an overfeed rate of 0% by using a pin tenter dryer.

< example 2 >

(preparation of yarn)

As warp yarns and weft yarns, synthetic fiber filaments similar to those of example 1 were prepared.

(weaving)

Then, weaving was performed in the same manner as in example 1.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried under the conditions shown in table 1 by the same method as in example 1. Then, the base fabric having been passed through the hot air dryer and kept at a surface temperature of 65 ℃ was subjected to heat setting processing in the same manner as in example 1.

< comparative example 1 >

(preparation of yarn)

As warp yarns and weft yarns, synthetic fiber filaments similar to those of example 1 were prepared.

(weaving)

Then, weaving was performed in the same manner as in example 1.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried under the conditions shown in table 1 by the same method as in example 1. Then, the heat setting process was performed in the same manner as in example 1 without performing the preheating process by the hot air dryer. The surface temperature of the base fabric in a state where the preheating process was not performed was 23 ℃.

< example 3 >

(preparation of yarn)

As the warp and weft, there was prepared a synthetic fiber filament yarn of nylon 6, having a circular cross-sectional shape and consisting of a single fiber 136 yarn having a single fiber fineness of 2.57dtex, a total fineness of 350dtex, a tensile strength of 8.4cN/dtex, an elongation of 23.5%, and no twist.

(weaving)

The yarns were used as warp and weft yarns, and a fabric having a weaving density of 60 threads/2.54 cm and a width of 200cm was woven by a water jet loom. At this time, the warp tension was adjusted to 70 cN/package, the shedding timing was 340 degrees, and the loom rotation speed was 600 rpm.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried by a usual method under the conditions shown in table 1. Then, the base fabric having a surface temperature of 44 ℃ by the hot air dryer was subjected to heat setting processing at 160 ℃ for 1 minute using a pin tenter dryer under a dimensional specification of 0% width growth rate and 0% overfeed rate.

< example 4 >

(preparation of yarn)

The same synthetic fiber filaments as in example 3 were prepared as warp yarns and weft yarns.

(weaving)

Then, weaving was performed in the same manner as in example 3.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried by the same method as in example 3 under the conditions shown in table 1. Then, the base fabric having a surface temperature of 69 ℃ maintained by the hot air dryer was subjected to heat setting processing in the same manner as in example 1.

< comparative example 2 >

(preparation of yarn)

The same synthetic fiber filaments as in example 3 were prepared as warp yarns and weft yarns.

(weaving)

Then, weaving was performed in the same manner as in example 3.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried by the same method as in example 3 under the conditions shown in table 1. Then, the heat setting process was performed in the same manner as in example 3 without performing the preheating process by the hot air dryer. The surface temperature of the base fabric in a state where the preheating process was not performed was 24 ℃.

< example 5 >

(preparation of yarn)

As the warp and weft, there was prepared a synthetic fiber filament comprising 136 filaments of nylon 6,6 having a single fiber fineness of 3.46dtex and a circular cross-sectional shape, a total fineness of 470dtex, a tensile strength of 8.4cN/dtex, an elongation of 23.5%, and no twist.

(weaving)

The yarns were used as warp and weft yarns, and a fabric having a weaving density of 53 threads/2.54 cm and a width of 200cm was woven by a water jet loom. At this time, the warp tension was adjusted to 100 cN/package, the shedding timing was 340 degrees, and the loom rotation speed was 600 rpm.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried by a usual method under the conditions shown in table 1. Then, the base fabric having a surface temperature of 44 ℃ maintained by the hot air dryer was subjected to heat setting processing at 160 ℃ for 1 minute using a pin tenter dryer under a dimensional specification of 0% width growth rate and 0% overfeed rate.

< comparative example 3 >

(preparation of yarn)

The same synthetic fiber filaments as in example 5 were prepared as warp yarns and weft yarns.

(weaving)

Then, weaving was performed in the same manner as in example 5.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried under the conditions shown in table 1 in the same manner as in example 5. Then, the heat setting process was performed in the same manner as in example 5 without performing the preheating process by the hot air dryer. The surface temperature of the base fabric in a state where the preheating process was not performed was 24 ℃.

< example 6 >

(preparation of yarn)

As the warp and weft, there was prepared a non-twisted synthetic fiber filament of nylon 6, which had a total fineness of 470dtex, a tensile strength of 8.4cN/dtex and an elongation of 23.5%, and which was composed of 136 filaments of single fiber having a single fiber fineness of 3.46dtex and a circular cross-sectional shape.

(weaving)

The yarns were used as warp and weft, and a fabric having a weaving density of 50 yarns/2.54 cm and a width of 200cm was woven by a water jet loom. At this time, the warp tension was adjusted to 90 cN/package, the shedding timing was adjusted to 340 degrees, and the loom rotation speed was adjusted to 600 rpm.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried by a usual method under the conditions shown in table 1. Then, the base fabric having a surface temperature kept at 43 ℃ by the hot air dryer was subjected to heat setting processing at 160 ℃ for 1 minute under a dimensional specification of 0% width increase rate and 0% overfeed rate using a pin tenter dryer.

< comparative example 4 >

(preparation of yarn)

The same synthetic fiber filaments as in example 6 were prepared as warp yarns and weft yarns.

(weaving)

Then, weaving was performed in the same manner as in example 6.

(refining and Heat-setting)

Next, the obtained fabric was appropriately refined and dried under the conditions shown in table 1 by the same method as in example 6. Then, the heat setting process was performed in the same manner as in example 6 without performing the preheating process by the hot air dryer. The surface temperature of the base fabric in a state where the preheating process was not performed was 24 ℃.

Tensile strength, tear strength, dynamic air permeability, 500Pa differential pressure air permeability, and 20KPa differential pressure air permeability were evaluated for each of the base fabrics obtained in examples 1 to 6 and comparative examples 1 to 4 by the following evaluation methods. The results are shown in Table 1.

[ evaluation method ]

(tensile Strength)

The tensile strength was measured every 20cm from one end of the base fabric in each of the warp and weft directions in accordance with JIS K6404-3 (1999)6, test method B (strip method), the yarn was removed from both sides of the width to make the width 30mm, the test piece was pulled at a grip interval of 150mm and a pulling speed of 200mm/min by a constant-speed pull type testing machine until the test piece was pulled apart, the maximum load at the time of the pulling-apart was measured, and the average value was calculated for each of the warp and weft directions. The CV value was calculated by dividing the standard deviation of the data collected every 20cm by the average value and multiplying the result by 100.

(tearing strength of base cloth)

(tear Strength)

The tear strength was measured in accordance with JIS K6404-4 (1999)6, test method B (one tongue method), in which a test piece having a long side of 200mm and a short side of 76mm was measured every 20cm from one end of the base fabric in the warp direction and the weft direction, a 75mm slit was introduced into the center of the short side of the test piece at right angles to the short side direction, and the test piece was torn by a constant-speed-pull type testing machine at a jig interval of 75mm and a tensile speed of 200mm/min until the test piece was pulled apart, and the tear load at that time was measured. From the chart trace of the obtained tear load, 3 points were selected in descending order from the maximum point from which the 1 st peak was removed, and the average value thereof was calculated. Finally, the mean values are calculated for the warp and weft directions, respectively. The CV value was calculated by dividing the standard deviation of the data collected every 20cm by the average value and multiplying the result by 100.

(dynamic air permeability)

The dynamic air permeability was measured every 20cm in the weft direction from one end of the base fabric by the method of ASTM D6476 using FX3350 manufactured by TEXTEST. The measuring pot used was 400cm³. CV values were calculated by dividing the standard deviation of the data collected every 20cm above by the mean value and multiplying by 100.

(500Pa differential pressure air permeability)

The 500Pa differential pressure air permeability was measured by FX3300 manufactured by TEXTEST corporation based on ASTM D3886 method every 20cm in the weft direction from one end of the base fabric. The differential pressure of the apparatus was set to 500Pa, and the measurement area was 100cm². CV values were determined by dividing the standard deviation of the data collected per 20cm above by the meanThe mean value, multiplied by 100.

(20KPa differential pressure air permeability)

The differential air permeability at 20KPa was measured every 20cm in the weft direction from one end of the base fabric by JIS L1096 (1999) 8.27.1A. A base cloth was attached to one end of a cylinder having a diameter of 100mm, the cylinder was fixed so as to be airtight from the fixed position, the test differential pressure was adjusted to 20KPa using a regulator, and the amount of air passing through the base cloth at this time was measured using a flow meter. CV values were calculated by dividing the standard deviation of the data collected every 20cm above by the mean value and multiplying by 100.

[ Table 1]

As shown in table 1, the base fabrics produced in examples 1 to 6 were excellent in uniformity of air permeability in the weft direction of the base fabric, and also excellent in uniformity of tensile strength and tear strength.

On the other hand, the base fabrics produced in comparative examples 1 to 4 had large variations in air permeability in the weft direction and mechanical strength. Therefore, the internal pressure retention and the driver restraining performance of the airbag may be uneven depending on the base fabric position obtained at the time of cutting.