JPH03276845A - Shock absorbing bag - Google Patents

Abstract

PURPOSE:To secure such an integral, tough product that is easy to wind, high in reliability and excellent in productivity by winding a very thin tape or tapelike material into a bag form, and specifying the diameter, strength, cutting elongation of filament constituting the tape and the width, thickness of the tape plus the number of filament layers. CONSTITUTION:A shock absorbing bag (what is called an air bag) is made up of winding a tapelike material of opening yarn, setting up a monofilament 6 so as to keep it almost rectilinear form and in a paralleling state or an opening yarn tape 5 into a bag form. In this case, the filament 6 should be set to be 5-50mum in diameter, more than 50kg/mm<2> in strength and 2-30% in cutting elongation. As for the tape 5, it should be set to be more than 5mm in width and less than 200mum in thickness. In addition, a layer of the filament 6 constituting the tape 5 should be set so as to be less than five layers in number.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is normally housed in the center of the steering wheel of a vehicle, and when a vehicle collides, it senses the impact and instantly expands and deploys to assist the driver. This invention relates to a shock-absorbing bag (so-called airbag) for ensuring safety, and a method for manufacturing the same.

[Conventional technology]

Airbags are used to instantly send gas into the bag by exploding gunpowder, so they must be able to withstand the impact.

The conventionally provided air hangs are:
After forming a polymer coating on one side of a flat woven fabric, the two coated woven fabrics are stacked so that the coated sides face each other, and the periphery is sewn to form a bag.

For example, in the prior art section of Japanese Patent Application Laid-Open No. 5mm-4742 (invention related to a bag for an airbag device and a method for manufacturing the same), it is stated that ``a circular piece of cloth is cut out from two square pieces of cloth and the periphery is sewn together. "Manufacturing a flat airbag" is disclosed.

[Problem to be solved by the invention]

However, the method of manufacturing airbags by sewing involves many manual processes (which makes it difficult to automate and cannot be manufactured economically), the strength of the sewing parts may be lower than other parts, and the strength of the sewing parts In addition, there are problems such as the time and effort required to test the air permeability, and there is also the problem that the sewing itself cannot be sufficiently reliable.

Therefore, if an excessively strong and thick woven fabric is used to improve reliability, the airbag becomes bulky and cannot be stored compactly in the center of the steering wheel or the like.

The present invention was made in view of the above-mentioned problems of the conventional technology, and its purpose is to provide a lightweight shock absorbing bag that is homogeneous, highly reliable, easy to manufacture, can be stored compactly, and is lightweight. It is about providing.

[Means to solve the problem]

In order to achieve the above object, the gist of the present invention is to provide a tape-shaped spread yarn in which fiber filaments are arranged in a substantially linear and parallel state, or a tape-shaped spread yarn wound into a bag shape. In the shock absorbing hang, the filament has a diameter of 5 to 50 μm and a strength of 50 kg/
The first invention provides a shock absorbing bag characterized by having a tape width of 5++m+ or more and a cutting elongation of 2 to 30%. A second invention provides a shock-absorbing bag characterized by the following: In the first invention, the shock-absorbing bag is characterized in that the number of filament layers constituting the tape is 5 or less. is the third invention.

In the specification of this application, "a tape-shaped spread yarn" refers to "one or several yarns (multifilament yarns) arranged in a sheet shape so that the monofilaments remain substantially straight and parallel. The term "spread yarn tape" refers to "a product in which the monofilaments constituting the spread yarn tape are mutually bonded and integrated."

The fibers of the present invention typically include human silk, polyvinyl alcohol fibers, aliphatic and aromatic polyamide fibers,
Examples include polyester fibers, carbon fibers, glass fibers, etc., but they are not particularly limited, and include all fibers conventionally used for bonding with rubber.

To obtain a tape-like spread yarn in which the fiber filaments are arranged in a substantially straight and parallel state, or a tape of the spread yarn, the fiber yarns can be prepared by an electrical method, a mechanical method, etc. The fibers may be opened by a method using air flow, etc., but any method may be used as long as the purpose can be achieved, such as the method disclosed in Japanese Patent Application Laid-Open No. 63-69626.

Note that the tape-like material obtained by the opening must be extremely uniform (with little variation in thickness). In addition, the monofilaments must be completely separated from each other, and the distance between them must be close enough that the average distance is less than the average diameter of the filaments.

To obtain a tape from a tape-like material, it is sufficient to coat the tape-like material with an elastomer.The tape-like material may be coated with an elastomer before the tape-like material is wound around a mandrel. It may be done after.

The elastomer desirably has flexibility and appropriate elasticity. This nidistomer can be used alone or in combination of two or more of natural rubber or synthetic rubber such as acrylic, urethane, polybutadiene, styrene butadiene, and ethylene propylene, and can be used as a reinforcing agent, a flame retardant side, and a vulcanized side. Compositions containing the following are preferred. If higher heat resistance than the above elastomer is required, use a heat-resistant elastomer consisting of synthetic rubbers such as chloroprene butyl rubber, halogenated butyl rubber, silicone rubber, and fluorine rubber, either singly or in combination, and use a reinforcing agent as well. A composition containing necessary ingredients such as , flame retardant, and vulcanizing agent is preferred.

Further, the ratio of filament to elastomer may be appropriately selected depending on the purpose and required characteristics, but for example, filament: elastomer = 90-40: 10-6.
A ratio (weight ratio) of 0 is used. In particular, in the present invention, since the filaments are spread apart, when impregnated with the above-mentioned elastomer solution, the monofilaments can penetrate well and the monofilaments can be bonded uniformly with a small amount of elastomer, thus relatively increasing the filament ratio. be able to. In particular, when the content ratio of filaments is 50% or more, it becomes possible to bring out unprecedentedly high strength properties. In order to have a high content ratio of filaments and to allow the elastomer solution to penetrate well between the monofilaments, the filaments must be opened sufficiently to incorporate the elastomer solution into the monofilaments, and then the excess elastomer must be removed using a sharp edge such as a doctor knife. If a method such as removing the elastomer is used, it is possible to increase the filament ratio and obtain a composite structure in which the filament and the elastomer are completely integrated.

The filling rate of the elastomer between the monofilaments is approximately 60% or more of the voids between the monofilaments, especially 70% or more of the voids between the monofilaments.
Preferably, it is 90% or more filled with elastomer. If this filling rate is low, the object of the present invention cannot be fully achieved.

In addition to dip coating methods, methods for coating filaments with elastomers include dip coating in a dispersion state, and methods in which elastomer is powder-injected or passed through a heated filament in an atmosphere in which it is scattered to melt and adhere. It can be carried out.

In the present invention, the tape or the tape may be wound around a mandrel having a predetermined size and shape. Or a special type in which the mandrel is wound with a special rotational movement can be applied.

Divided by shape, there are three methods: a method for wrapping closed shapes such as a cocoon, a sphere, and a cone, a method for wrapping a cylinder, a disk, and other shapes, and a method for wrapping irregular shapes such as a prism and pyramid. But it can be applied.

Although there are various winding patterns, a predetermined strength can be imparted by broadly classifying them into parallel winding, helical winding, longitudinal winding, or a combination thereof. In cases where pressure is generated inside the bag, such as in an airbag, by forming the bag with a laminated structure of at least two or more layers with different winding directions, the pressure can be applied uniformly.

When molding into a removable shape, use a deformable hollow body, such as a metal mandrel (which can be disassembled if necessary) or a rubber mandrel, and mold it into a closed shape. If so, use a consumable mandrel made of gypsum, rock salt, easily fused metal, etc. In order to easily remove the mandrel after molding, it is desirable to apply a mold release agent to the mandrel in advance.

When the elastomer is made of a rubber composition, it is desirable to perform a vulcanization treatment, and this vulcanization treatment involves fusion-welding the adjacent filaments in a crossing or parallel state with an elastomer that has previously covered the filaments. This is done to maintain the shape after molding and to protect the filament. The temperature conditions are the temperature at which the elastomer covering the filament develops a predetermined adhesive force, that is, 120~
The temperature is preferably 190°C, and harsh conditions such as a heating temperature of 200°C or more and a heating time of 20 minutes or more should be avoided in consideration of thermal decomposition of the elastomer.

[Effect]

Since it is a tape-shaped spread yarn or a tape of spread yarn wound into a bag shape, it is compact and has high reliability.
Moreover, since no sewing is required, the production process can be streamlined.

However, if the diameter of the filament is less than 5 μm, troubles such as cutting or fraying are likely to occur when the filament is opened or when a tape-like spread yarn is coated with an elastomer. On the other hand, the filament diameter is 50μ
If it exceeds m, the bending stiffness of the filament, λ, is
The bending rigidity of the spread yarn increases, making it difficult to store it as a shock absorbing link.

For the reasons mentioned above, the diameter of the filament is preferably 5 to 50 μm, particularly preferably 10 to 30 μm).

Furthermore, if the strength of the filament is less than 50 kg/wr, it is necessary to increase the number of wraps of the tape in order to obtain a shock-absorbing nozzle with a predetermined strength, resulting in increased bulk and poor storage performance. Problems occur.Furthermore, the filament is likely to break during opening.

In addition, if the elongation at break of the filament is less than 2%, the filament is likely to be cut or disorganized during opening, while if the elongation at break is more than 30%, the modulus of elasticity is low, and it can be expanded and expanded as a shock-absorbing tong. When used as an airbag, abnormal deformation tends to occur at the initial stage of deployment (when used as an airbag,
They may not be able to fulfill their original function of protecting the safety of passengers.

For the reasons mentioned above, the strength of the filament is 50kg/f.
i12 or more is preferable, and elongation at break is preferably 2 to 30%.

If the width of the spread yarn tape is less than 5 mm, it will take a long time to make the shock absorbing bag, and the thickness will be less than 200 μm.
If it is m@, the manufactured bag will be bulky and will be difficult to store.

For the reasons mentioned above, it is preferable that the width of the spread yarn tape is 5 mm or more and the thickness is 200 μm or less.

When the number of filament layers that make up the tape exceeds 5,
The elastomer solution does not sufficiently penetrate between the monofilaments, making it impossible to obtain an integrated filament and elastomer, and making it impossible to produce impact-absorbing knots having a predetermined strength.

Therefore, the number of filament layers constituting the tape is preferably five or less.

〔Example〕

Examples of the present invention will be described below.

In Fig. 1, ■ is a tape-shaped spread yarn obtained by opening a tow-shaped polyparaphenylene/3.4 diphenyl ether terephthalamide yarn; The diameter of the filament constituting the is 25 μm, the strength is 100 kg/mm”, and the elongation at break is 8%.Then, the tape-shaped spread yarn 1 is passed through the rubber solution impregnating device 2, and the After impregnating the rubber solution 3 made by dissolving the rubber composition shown in toluene in toluene, the adhesion amount was controlled to 20 g/m Z using a doctor knife 4. The arrow indicates the direction of travel of the tape-shaped spread yarn 1. .

The rubber solution coated in this way has a thickness of 8 mm.
An extremely thin tape 5 having a thickness of 0 μm and a width of 10 mm was obtained. An enlarged cross-section of this child-15 is shown in FIG.

In FIG. 2, 6 is a monofilament.

Then, the tape 5 is passed between opposing rollers 7.8, passed through rollers 9.10, and then passed through the disc-shaped mandrel 13.
The delivery eye 1 reciprocates in a direction parallel to the rotation axis 12 of the
1, onto a decomposable metal disc-shaped mandrel 13 coated with a release agent in advance, at an angle of 14.5°.
The tape was wound uniformly at a feeding speed of 0.45 m/sec until there were no gaps. The above-mentioned FIG. 2 is an enlarged view of the cross section of the tape 5 and the edge of the disc-shaped mandrel 13.

Thereafter, the monofilaments were vulcanized under heat and pressure conditions of 180"C10.5kg/cm2 to firmly bond the monofilaments with rubber.Then, the disc-shaped mandrel 13 was disassembled and the shock absorbing material formed on the mandrel was vulcanized. The shock absorbing bag 14 was taken out.The inflated and deployed state of the shock absorbing bag 14 is shown in FIG.

Table 1 (Comparative Examples) Next, as Comparative Examples 1 to 7, shock absorbing bags were produced in the same manner as in the above examples.

In this case, the diameter, strength, and
The elongation at break, the width and thickness of the spread yarn tape, and the number of filament layers were as shown in Table 2.

(Performance evaluation of bags) The bags according to Examples and the bags according to Comparative Examples 1 to 7 were evaluated in terms of processability during opening, presence or absence of deformation during unfolding, storability, and productivity according to the following method. did.

(a) Workability during opening = whether or not filament breakage and other troubles did not occur during opening was evaluated.

b) Deformation during expansion = uniform expansion during expansion, and it was evaluated whether there was any non-uniform deformation.

(C) Storage capacity: The height of the bags when folded into a 20 cm square and stacked was measured, and expressed as an index with the height of the example as 100. A high index indicates a lack of flexibility and poor storability.

(c) Productivity = The time required to produce one shock-absorbing bag is measured, and the reciprocal of the time is expressed as an index with the value of the example as 100. The smaller this index is, the worse the productivity is. .

The above results are shown in Table 2 on the next page.

From Table 2, the following points are clear.

■The shock-absorbing hang according to the example has good processability during opening because the diameter, strength, and elongation of the filament as well as the width and thickness of the tape of the opening yarn are appropriate within the scope of the present invention. It does not deform when inflated or unfolded, and has excellent storage properties.
Productivity is good.

(2) In Comparative Example I, the filament diameter was too small and the filament broke during opening, making it impossible to produce an airbag.

■In Comparative Example 2, the filament diameter was too large;
Furthermore, since the tape is too thick, it is extremely difficult to store and has poor productivity.

■In Comparative Example 3, since the strength of the filament was low, filament breakage occurred during opening, making it impossible to produce an airbag.

(2) In Comparative Example 4, the elongation at break of the filament was low, so filament breakage occurred during opening, making it impossible to produce an airbag.

(2) In Comparative Example 5, the elongation of the filament at break was abnormally large, so the filament did not expand uniformly during expansion, and local deformation occurred.

(4) Comparative Example 6 has extremely low productivity because the tape width is narrow.

(2) Since the tape according to Comparative Example 7 has a large thickness, it has poor storage properties and poor productivity.

〔Effect of the invention〕

■The shock absorbing bag according to the present invention is different from bags formed from woven or knitted fabrics, and has a structure in which an ultra-thin tape or tape-like material is wound into a bag shape, and the diameter of the filament constituting the tape, Strength, cutting elongation, tape width, thickness, and number of filament layers are appropriate, so it is easy to wrap, compact, and has high reliability.Moreover, it does not require sewing, so it is highly productive, and does not deform when expanded. It is an invention that has a strong, integrated structure, and has extremely excellent practical effects.

■Since the present invention can provide a hang with an arbitrary shape and strong integral structure, the shock absorbing bag according to the present invention
In particular, it has an exhaust port, a mounting port, etc., and is ideal for automotive airbags that require high strength. In addition, by changing the ratio of filament and elastomer, the shock absorbing bag according to the present invention can be used for gases such as hot air balloons, atto balloons, balloons such as airships, shock absorbing bags for collisions of high-speed moving objects, etc. It can be applied to gas bags to block blasts caused by explosions in mines, flexible containers for powder, fuel tanks and water storage tanks for liquids, and heat-resistant insulation materials for civil engineering construction work.

[Brief explanation of drawings]

Figure 1 is a side view of each step in manufacturing the shock absorbing hang of the present invention, Figure 2 is an enlarged view of the cross section of the tape coated with rubber solution and the edge of the mandrel, and Figure 3 is the shock absorbing hang of the present invention. FIG. 2 is a perspective view of the inflated and expanded state.・Tape, ・Monofilament, 14. ・Shock absorbing hang

Claims (1)

[Claims] 1) A tape-shaped spread yarn in which fiber filaments are arranged in a substantially straight and parallel state, or a shock-absorbing tape formed by winding the spread yarn tape into a bag shape. In the bag, the filament has a diameter of 5 to 50μm and a strength of 50K.
g/mm^2 or more and a breaking elongation of 2 to 30%. 2) A tape width of 5 mm or more and a tape thickness of 20%.
3) The impact-absorbing bag according to claim 1, wherein the number of filament layers constituting the tape is 5 or less.