JPH02220946A - Cover for containing air bag - Google Patents

Abstract

PURPOSE:To eliminate any feeding of discomfort to a human body and also to prevent fragments from scattering by constituting a cover by a facing layer made of thermoplastic polymer of 20-90 in hardness and a core layer made of thermoplastic resin of 100kgs/cm<2> or more in a bending elastic modules with the hardness of the core layer more than that of the facing layer and having a cleavage section. CONSTITUTION:A cover 1 consists of a facing layer 1A made of thermoplastic polymer of 20-90 in JIS-A hardness and a core layer 1B which is laid under the facing layer 1A and made of thermoplastic resin of 1000kgs/cm<2> or more in JIS-K7203 bending elastic modulus and harder than the facing layer 1A. A slit form like perforations for readily cleaving the cover 1, is formed on the core layer 1B when an air bag 2 starts its operation. Therefore, since discomfort feeling to a human body is eliminated because of the soft facing layer 1A, and since the hard core layer 1B is tightly covered by the facing layer 1A, fragments in cleaving are prevented from scattering. This improves safety.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cover for accommodating an air bag that is inflated and deployed by sensing the impact, deformation, etc. at the time of a vehicle collision.

[Prior Art] This type of cover has the risk that when the airbag is activated (inflated), the cover containing the airbag will be crushed, and the fragments will fly off and hit the occupant's face or eyes, causing injury. Because of this, conventional products generally have a reinforcing material (such as a net) inserted in order to prevent fragments from scattering. (JP-A-62-234764, JP-A-50-127336, JP-A-52-80928, JP-A-Sho 50
-43454, Utility Model Application Publication No. 51-25342, etc.).

Covers with such net-like inserts are usually manufactured by making the entire cover out of a relatively low-strength material such as polyurethane foam, and inserting a reinforcing net into the entire cover. It is common to provide a line in which the reinforcing material net is not inserted so that the reinforcing material net can be easily expanded and the cover easily destroyed when inflated.

On the other hand, Japanese Utility Model Application Publication No. 52-76042 discloses that a skin layer made of hard urethane foam is used to finish the surface neatly, and a core layer is made of low-density (high-magnification foamed) urethane foam to make the entire cover soft. An airbag storage cover has been proposed that is composed of two layers and includes a slit (a line for smoothly deploying the airbag when the airbag is inflated) that extends from the core layer to a part of the skin.

[Problems to be Solved by the Invention] Among the above-mentioned conventional air bag storage covers, the air bag storage cover with a net-like insert inserts a net-like reinforcing material, which requires a large number of manufacturing steps and is complicated. , Also, even if urethane foam molding (RIM)
Even with the use of the same method, it is difficult to manufacture with high precision, and there are problems in that the yield is low and the cost is high.

Furthermore, the cover disclosed in Japanese Utility Model Application Publication No. 52-76042 has a surface made of hard urethane foam (ASTM-D2240
, Shore hardness is 30 to 40), so if a part of your body hits it while driving a vehicle, you will not feel the softness and will feel uncomfortable. Additionally, urethane-based materials have low impact strength and lack of reinforcing inserts, which can cause debris to fly when the airbag is inflated.

The present invention solves the above-mentioned problems of conventional air bag storage covers, the skin layer gives a soft feel, the core layer maintains a shape that can withstand external pressure, and has a temperature range of -40°C.
In a temperature range of 80 degrees Celsius, the airbag is easily destroyed when inflated, but not only does it not scatter fragments, but it also remains the same even after being exposed to high temperatures of 110 degrees Celsius for 500 hours in consideration of actual vehicle installation. This is a cover for airbag storage that has the same good breaking performance in the temperature range and has almost no change in appearance, and is manufactured using a simple molding method such as injection molding that does not produce defective products. It is an object of the present invention to provide an air bag storage cover that can be supplied with high yield, high precision, high productivity, and good economic efficiency.

[Means for Solving the Problem] The air bag storage cover of claim (1) contains a hydrocarbon rubber softener and has a JIS-A hardness of 20 to 90 according to JIS-6301. The skin layer is made of a plastic polymer and the flexural modulus of JIS-7203 is 1.
000 kg/cm2 or more, the core layer has a harder hardness than the skin layer, and the core layer has a portion that easily ruptures when the airbag starts operating. The air bag storage cover according to claim (2) is characterized in that it is affixed with JIS-
It contains a skin layer made of a thermoplastic polymer with a JIS-A hardness of 20 to 90 according to JIS-6301, and an olefin rubber, and has a flexural modulus of JIS-7203 of 10.
00 kg/c rn" or more, the core layer has higher hardness than the skin layer, and the core layer has a layer that is easily ruptured when the airbag starts operating. The air bag storage cover according to claim 3, characterized in that it has a part for hardening, contains a softening agent for hydrocarbon rubber, and has a JIS-A hardness of 6301 in accordance with JIS-6301. contains a skin layer made of a thermoplastic polymer with a diameter of 20 to 90, an olefin rubber, and a JIS
- a core layer made of a thermoplastic resin having a flexural modulus of 7203 of 1000 kg/cm or more, the core layer having a higher hardness than the skin layer; It is characterized by having a part attached to it for easy cleavage.

That is, in order to achieve the above object, the inventors of the present invention have made extensive studies, and have adopted a specific skin layer and a specific core layer, and provided the core layer with an easily cleavable portion, for example, a brittle shape. The inventors have discovered that the above object can be achieved by applying the above-mentioned methods, and have completed the present invention.

The present invention will be explained in detail below with reference to the drawings.

FIG. 1 is a schematic partial sectional front view showing a state in which an air bag storage cover according to an embodiment of the present invention is attached to an air bag, and FIG. 2 is a rear view of the air bag storage cover. .

In the figure, 1 is an air bag storage cover, 2 is an air bag, 3 is an inflator, 4 is a ring retainer, 5 is a pace retainer, 6 is a plate, 7 is a rivet, IA is a skin layer, IB is a core layer, and IC is a sewing machine. It is an eye-shaped slit.

As shown in the figure, the air bag storage cover 1 of the present invention includes:
The skin layer IA contains a softener for hydrocarbon rubber,
Or it does not contain and JIS-6301 JIS-
A skin layer made of a thermoplastic polymer having an A hardness of 20 to 90 is used. The content of the hydrocarbon rubber softener in the skin layer IA is suitably 30% by weight or less, and the thermoplastic polymer is suitably an olefin thermoplastic elastomer and/or a styrene thermoplastic elastomer.

On the other hand, as the core layer IB, a core layer made of a thermoplastic resin containing or not containing olefin rubber and having a flexural modulus of JIS-7203 of 110001c/crn" or more is used. The content of the olefin rubber in the core layer IB is suitably 60% by weight or less, and the thermoplastic resin is preferably an olefin resin.

This core layer IB has a higher hardness than the skin layer IA, and the core layer IB has a fragile shape IC1, such as a thin notch shape or a perforated slit, as a part to easily rupture when the airbag operation starts. It has a certain shape, etc.

In the present invention, the surface layer IA contains or does not contain a softener for hydrocarbon rubber as a constituent material, and is compliant with JI
As the olefin thermoplastic elastomer having a JIS-A hardness of 20 to 90 in S-6301, olefin rubber such as EPM%EPDM, ethylene-butene-1
A copolymer rubber or the like and an olefin resin such as polypropylene or polyethylene, if necessary, a predetermined amount of a softener for hydrocarbon rubber such as paraffin oil or naphthenic oil, and optionally an inorganic filler such as Compounds filled with various fillers such as calcium carbonate, silica, talc, colorants, stabilizers, etc., or JP-A-46-2
683+3, JP-A-52-13541. JP-A-52-3
7953, JP-A No. 56-98248, etc., and which have a partially crosslinked structure are suitable.

In addition, as a styrenic elastomer having the above-mentioned properties that can be used for the skin layer IA, a block copolymer consisting of a monovinyl aromatic hydrocarbon polymer block and a conjugated diene elastomeric polymer block or a hydrogenated derivative thereof is used. Examples include thermoplastic elastomers as base polymers. These base polymers can be obtained by conventional methods such as living polymerization using a lithium catalyst. Among these, those in which the base polymer is a hydrogenated derivative of a styrene polymer block and a butadiene and/or isoprene polymer block are preferred in terms of weather resistance, heat aging resistance, flexibility controllability, and the like.

More specifically, the styrenic thermoplastic elastomer constituting the skin layer IA includes the above base polymer, various thermoplastic resins such as olefin resins, styrene resins, etc., and optionally the above olefin elastomer. Preferably, a similar predetermined amount of a softener for hydrocarbon rubber, an inorganic filler, etc. is combined as necessary to control quality such as hardness.

The constituent materials of the epidermal layer IA include the above-mentioned olefins,
The styrenic thermoplastic elastomers are not limited to being used alone, but may also be used as a mixture in an appropriate ratio.

As mentioned above, the content of the hydrocarbon rubber softener in the skin layer IA is preferably 30% by weight or less, but if the content of the hydrocarbon rubber softener exceeds 30% by weight,
After 0 hours, appearance defects (deformation, etc.) occur, and -
There is a problem in that when the air bag is inflated at 40° C., fracture failure occurs, that is, fracture occurs at locations other than the predetermined fragile portions, and fragments are scattered.

As for the amount of softener for hydrocarbon rubber, in addition to the above-mentioned problems, it is necessary to consider hardness (soft feel) and moldability, but when these are taken into consideration, it is preferably 20% by weight or less, and The range is preferably 10% by weight or less, and the lower limit when adding this is preferably 1% by weight, more preferably 3% by weight from the viewpoint of final quality.

In the present invention, the thermoplastic polymer constituting the skin layer IA is selected from those with a JIS-A hardness of 20 to 90, but those with hardness below the above range are highly flexible but have poor moldability. (For example, injection moldability), mechanical strength is poor and easy to break. Further, those having a hardness exceeding the above range have no problem in molding processability, but have the disadvantage that they have a poor soft feel and are not practical. Hardness 20~
The selection of hardness within the range of 90 varies depending on the thickness of the skin layer, but it is preferably in the range of 30 to 70, more preferably in the range of 40 to 65.

The thickness of the epidermis layer IA usually varies depending on the part of the cover 1 and is not completely uniform over the entire cover, but in the present invention, the thickness of the epidermis layer IA is 70% or more of the surface area,
Preferably, 80% or more of the portion has a thickness of 0.5 mm or more. Although there is no particular upper limit to the wall thickness, it is appropriate to set it to about 10 mm or less in consideration of design, economy, soft feel, airbag operating performance, molding process, etc.

Further, the skin layer IA may be foamed to a diameter of 3.0 times or less for the purpose of improving the soft feel and weight reduction.

In the present invention, used as a constituent material of the core layer IB,
Contains or does not contain olefin rubber, JIS-
Examples of the thermoplastic resin having a flexural modulus of 7203 of 1000 kg/cm' or more and a higher hardness than the thermoplastic polymer of the skin layer IA include homopolymers or copolymers of α-olefins such as ethylene and propylene. etc. are suitable. Also, EPM is an olefin rubber.

EPDM, ethylene, butene-1 copolymer rubber, etc. can be mentioned. These may be used alone or in a blend of two or more. Furthermore, as long as the elastic modulus and hardness are within the above ranges, other various resins, elastomers, glass fibers, various fillers such as talc, calcium carbonate, silica, mica, colorants, stabilizers, etc. It may be filled with an agent or the like.

As mentioned above, the content of the olefin rubber in the core layer IB is suitably 60% by weight or less, but if the olefin rubber exceeds 60% by weight in the composition of the olefin resin and olefin rubber , problems arise in moldability and mold retention.

In the present invention, if the thermoplastic resin constituting the core layer IB has a flexural modulus of less than 1000 kg/am" or has a hardness lower than the thermoplastic elastomer of the skin layer IA, sufficient shape retention will not be achieved. It easily deforms due to external pressure, making it unsuitable as an airbag storage cover.On the other hand, those with a bending modulus of elasticity exceeding 10,000 kg/c have poor overall softness as a two-layered airbag cover and are unsuitable for use as an airbag storage cover. Breakage failure is likely to occur during airbag operation.Therefore, the bending elastic modulus is set at 1000 kg/c from the viewpoint of softness, operating characteristics, and shape retention of the entire cover.
m2 or more, toooo.

kg/crr or less, especially 1500kg/crr
? ~7000 kg/crn' is preferred.

A particularly preferable range is 2000 kg/cd to 50
00 kg/cm'.

There is no particular limit to the wall thickness of the core layer IB, but it is generally 0.
The thickness is about 5 to 5 mm, preferably about 1 to 3 mm.

In the present invention, the core layer IB made of such a thermoplastic resin is given a brittle shape so that the core layer IB easily ruptures when the airbag operation starts.

In addition to the perforated slit-shaped IC, this fragile shape
Notch-like thin-walled shapes and various other shapes can be adopted. Further, there are no particular restrictions on the formation location, formation range, etc., and are appropriately determined depending on the shape, strength, stress during airbag operation, etc. of the core layer IB.

Next, a method of manufacturing the air bag storage cover of the present invention will be described.

Examples of molding methods for manufacturing the airbag storage cover of the present invention include general molding methods used for thermoplastic resins, but injection molding is particularly preferred from the point of view of design, etc. can.

The injection molding method is the so-called insert injection method in which a core layer is molded in advance, the molded product is mounted in a mold leaving a space for the skin layer, and a skin material made of thermoplastic polymer is injection molded into the skin layer. Alternatively, the core layer is molded, then the cavity mold is separated, and without taking out the core molded product from the mold, a new cavity mold having a skin layer space is continuously covered and the skin material is injection molded. A two-color molding (double injection) method can be cited as an effective molding method.

At this time, it is necessary to give the core layer IB the aforementioned brittle shape so that the airbag can easily rupture when the airbag starts operating. As mentioned above, the fragile shape includes a notch-like thin shape, a perforation-like slit shape, etc., but this shape may be formed by molding with a mold having the shape when molding the core molded product. Alternatively, after the core molded product is molded, it may be processed to give such a shape, and then the skin layer may be laminated.

The airbag cover of the present invention may have the skin layer IA coated if necessary in order to improve the luxury of the vehicle interior, color matching with other interior parts, feel, etc. Coating the skin layer IA is also preferable from the viewpoint of hot water resistance.

[Function] In the air bag storage cover of the present invention, since the relatively hard core layer is covered with the soft skin layer,
Even when the body touches the cover, it is soft and does not make the user feel uncomfortable. Further, since the core layer is hard, the cover will not be deformed or damaged even if some external force is applied.

In addition, the cover of the present invention can be used in a temperature range of -40°C to +80°C, so that when the airbag inside the cover expands during a vehicle collision, etc., the cover conforms to the fragile shape formed in the core layer in advance for cover rupture. However, when the cover is torn, the hard core layer is tightly covered with the soft skin layer, so the cover torn pieces will not be scattered.

Furthermore, the cover of the present invention can be heated to 110 degrees Celsius in consideration of mounting on an actual vehicle.
Even after 500 hours, the above temperature range (-40℃
It shows good fracture performance at temperatures up to +80°C, with almost no change in appearance observed.

[Examples] Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof.

Examples 1 to 7, Comparative Examples 1 to 6 Using an in-line screw two-color injection molding machine with a mold clamping pressure of 350 tons, a perforated slit (about 0.7 cm long) for cleavage was formed using the core material shown in Table 1. A core layer (thickness: 1.0 to 3.0 mm) containing 29 fibers (29 pieces) is molded, and then a skin layer is formed with the skin material shown in Table 1 on top of it to a predetermined thickness. The air bag module cover 1 shown in FIG. 1 was obtained by injection molding.

In addition, in Example 6, in zero-foam molding in which a foamed skin layer was molded, 5 parts of a carbon dioxide blowing agent masterbatch (Fine Blow 32ON manufactured by Mitsubishi Yuka Co., Ltd.) was triblended with the skin material in two-color molding. Molded.

Furthermore, in Example 7, the skin layer was painted.

For painting, after injection molding the cover, wipe the skin layer with isopropyl alcohol, then apply Brimer (MEX) manufactured by Itaben Kagaku Co., Ltd.
5440 and methyl ethyl ketone (1:1) to 7-10 μm
After spraying and drying at room temperature for 10 minutes, apply urethane top coat (MEX-8047: Curing agent F) manufactured by Itaben Kagaku Co., Ltd.
-3: Thinner 58u = 100: 10: 50)
This was carried out by spray coating 20 to 25 μm, drying at room temperature for 10 minutes, and baking at 80° C. for 30 to 45 minutes.

The obtained product was evaluated by the method described below, and the results were evaluated in the first
Shown in the table.

The materials used in Table 1 are as follows.

[Core material] PP-1: Blend of propylene-ethylene block copolymer resin and ethylene-propylene rubber (BC4 manufactured by Mitsubishi Yuka/EPO7p manufactured by Japan Synthetic Rubber Co., Ltd. = 50150
(wt%)) BO2: MFR (230℃, 2.16kg
) 6.5 g/10 minutes Flexural modulus 11600 kg/c GoEPO7p: ML (100°C) 70 Propylene content 27% Blend: Flexural modulus 2000 kg/cr
n'JIS-A hardness 97 PP-2: Blend of propylene-ethylene block copolymer resin and ethylene-propylene rubber (BC4 manufactured by Mitsubishi Yuka/EPO7p-60/40 manufactured by Nippon Synthetic Rubber)
(% by weight)) Blend; Flexural modulus 4000 kg
/cm' JIS-A hardness 99 PP-3: Propylene homopolymer resin (Mitsubishi Yuka M
A-4) MFR5g/10 minutes flexural modulus 12000kg/c
A hardness: 100 PP-4: Blend of brobylene-ethylene block copolymer resin and ethylene-propylene rubber (Mitsubishi Silver Oil MA-47 Nippon Synthetic Rubber EPO7P = 30/70
(% by weight)) Blend: Flexural modulus 500 kg
/ cm” JIS-A hardness 86 PE-1: Low pressure polyethylene resin (Mitsubishi Yuka JX-
10) MFR (190℃, 2.16kg) 20g/lo bending modulus 9000 kg/cm JIS-A
Hardness: 100 PE-2: Blend of linear low-density polyethylene resin and ethylene-propylene rubber (Mitsubishi Yuka UJZ807
Japan Synthetic Rubber EPO7p=40/60 (weight%) UJ280: MFR (190°C, 2.16kg) 30g
/10 minutes Flexural modulus 2600 kg/crn' Blend: Flexural modulus 400 kg/crn'
"JIS-A hardness 82 [Skin material] TPS-1: Consists of the following four components, ■5EBS
-1/■5PX9400/■PIB-1/■OIL Fuji 3
1 with a blending composition of 5/15/40/10 (wt%)
00 parts by weight, 0.2 parts by weight of Irganox 1010 manufactured by Chipa Geigy as a stabilizer, and 0.0 parts by weight of carbon black.
5 parts by weight was added and kneaded at 200°C in a twin-screw extruder.

JIS-A hardness; 55 ■ Hydrogenated derivative of styrene-butadiene block copolymer (SEBS-1); Brookfield viscosity 20% by weight (toluene solution 2000 cps, 25°C) ■ Brobylene-ethylene block copolymer (resin Mitsubishi Yuka 5PX9400).

MFR (230℃, 2.16kg) 6g/10min, flexural modulus 4500kg/crr? ■Polyisobutylene (P
IB-1) (Tetrax 3T manufactured by Nippon Petrochemicals); Viscosity average molecular weight 30000 ■ Softener for paraffin rubber (OI L) (PW380 manufactured by Idemitsu Kosan); Kinematic viscosity at 40°C 80 cSt TPS-2: Same as TPS-1 Prepared using the following method using the following composition.

■5EBS-1/■5PX9400/■PIB-1/■
OI L = 35/15/30/20 (wt%) JIS A hardness = 45 TPS-3: Same as TPS-1 using hydrogenated derivative of styrene-butadiene block copolymer (SEBS-2) Prepared using the following method using the following composition.

■5EBS-2/■5PX9400/■PIB-1/■
OI L = 45/15/30/10 (wt%) JI S-A hardness = 68 However, ■5EBS-2 has a Brookfield viscosity of 20 wt% (toluene solution 1500 cp
s, 25°C).

TPS-4: Prepared with the following composition in the same manner as TPS-1.

5EBS-1/5PX940010IL=3515/6
0 (wt%) JIS-A hardness = 15 TPS-5: Prepared with the following composition in the same manner as TPS-1.

5EBS-1/BC-410I L/calcium carbonate=
24/9/37/30 (wt%) J I S-A hardness ≠ 55 TPO-1 Niolefin thermoplastic elastomer (Thermolan 3600B manufactured by Mitsubishi Yuka) J I S-A hardness = 70 TPO-2 Niolefin thermoplastic elastomer Elastomer (Thermolan 3920B manufactured by Mitsubishi Yuka) JI S-A hardness = 93 Comparative example 7 For the purpose of comparison, an airbag storage cover consisting of two layers: a skin layer of high-density urethane foam and a low-density urethane core layer. - was manufactured and evaluated.

Molding is performed by insert molding, in which the core layer is molded in advance at a low foaming density using the rim urethane molding method and cured (hardened), then attached to a mold to form the skin layer, and then the skin layer is molded using the same method. It was done by law. Freon gas was used as the foaming material for forming the skin layer. This method required two curing steps and had poor productivity.

An example of the obtained air bag storage cover!
The evaluation was carried out in the same manner as above, and the results are shown in Table 1.

Comparative Example 8 For further comparison, an air bag storage cover provided with a reinforcing net was manufactured and evaluated.

In this net-containing rim urethane molding, two-layer molding was carried out in the same manner as in Comparative Example 7. Polyester fibers were woven into a net shape, which was melt-cut in a shape along the cleavage of the cover, and metal fittings (hooks) were attached. Attach this to the rim mold,
The rim was molded with urethane. At this time, chlorofluorocarbon gas was used as a foaming material, and after demolding, it was cured at 100° C. for 30 minutes. This method had drawbacks such as the difficulty of creating a safe skin layer by inserting the net, and the slow molding cycle.

Regarding the obtained air bag storage cover, Example 1
The evaluation was carried out in the same manner as above, and the results are shown in Table 1.

As is clear from Table 1, the airbag storage covers of the present invention shown in Examples 1 to 7 have a soft feel, shape retention, -40°C deployment test, 110°C, 500 hour durability. Both testing and productivity were very good.

[Evaluation method] ■ Soft feeling As shown in Figure 1, the module cover or cover 11 is assembled with the airbag 2, airbag storage cover 1, retainer (mounting hardware) 4.5, and inflator 3.
The L product was left at -20°C to 80°C until the sample reached the ambient temperature, and the cover was then evaluated by touch with the hands of 10 people. 10 out of 10 people felt it felt soft.
○ if it is 8 out of 10 people, △ if it is 8 out of 10 people, X if it is less than that
And so.

■ Shape retention As shown in Figure 1, the module cover assembled with the airbag 2, airbag storage cover 1, retainer (mounting hardware) 4.5, and inflator 3, or the cover 1 alone, is heated to 80℃ to 110℃. ℃ for a long time (<too.

hr) Leave it alone or heat cycle from -40℃ to 100℃ for 1
Leave it for 0 cycles, observe the state of deformation during or after the test, and if there is almost no deformation, it is considered suitable as an air bag storage cover (0), and if there is significant deformation, it is not suitable as an air bag storage cover (× ).

■ -40℃ Deployment Test Attach the module assembled in ■ and ■ to the steering wheel and leave it for a period of time to reach the ambient temperature of 40℃, and conduct the deployment test within 1 minute. At that time, the module cover cracks and scatters. Cases in which the airbag did not function normally (such as the cover cracking into sharp shapes) or tearing the lugs were marked as unsuitable (×), and cases in which the cover operated normally were marked as suitable (0). .

■ Durability test at 110℃ for 500 hours After aging the module cover under the above conditions using a gear-type heat aging tester, we conducted a development test at -40℃ according to the test method in ■, and further compared the appearance of the module cover before and after aging. , those with significant changes such as warpage, deformation, and bleeding of the softener into the core material were rated ×, and those without were rated O.

■ Productivity Manufacture 20 products in a row and check the external dimensions and weight of the molded products. If all of them pass the level, mark O, if 90% or more, mark △, and below that mark × [Details of the effects of the invention] As described above, the air bag storage cover of the present invention has a soft skin layer, so even if a part of the body hits it, it remains soft, providing a high sense of comfort. Furthermore, since the core layer is relatively hard, it has excellent shape retention and high durability. Then, when the airbag is activated, the cover quickly ruptures due to the fragile shape for rupturing the cover. Moreover, the soft skin layer reliably prevents the core layer from scattering when the cover is torn, and also exhibits good breaking performance, significantly improving durability (
Can be measured.

Therefore, the air bag storage cover of the present invention can be easily and precisely manufactured using a streamlined molding method such as the two-color molding method, with almost no defective products, and with a high yield and reliably and efficiently. It is possible to significantly reduce the cost of the product.

[Brief explanation of the drawing]

FIG. 1 is a schematic partial sectional front view showing a state in which an air bag storage cover according to an embodiment of the present invention is attached to an air bag, and FIG. 2 is a rear view of the air bag storage cover according to an embodiment of the present invention. be. 1...Airbag storage cover IA...Skin layer, IB...Core layer, 2...
・Air bag, 3...Inflator-4, 5・
・Retainer. Agent Patent Attorney Tsuyoshi Shigeno

Claims (3)

[Claims] (1) Contains a softener for hydrocarbon rubber, and conforms to JIS
- having a skin layer made of a thermoplastic polymer with a JIS-A hardness of 20 to 90 according to K6301, and a core layer made of a thermoplastic resin with a flexural modulus of JIS-K7203 of 1000 kg/cm^2 or more, the core 1. A cover for storing an air bag, wherein the layer has a harder hardness than the skin layer, and the core layer has a portion for easily tearing when the air bag starts operating. (2) JIS-A hardness of JIS-K6301 is 20 to 9
0 thermoplastic polymer, contains olefin rubber, and conforms to JIS-K7203.
and a core layer made of a thermoplastic resin with a bending modulus of 1000 kg/cm^2 or more, the core layer has a higher hardness than the skin layer, and the core layer has a core layer made of a thermoplastic resin having a bending elastic modulus of 1000 kg/cm^2 or more, and the core layer has a hardness higher than that of the skin layer. An air bag storage cover characterized by having a part for easy tearing. (3) Contains a softener for hydrocarbon rubber, and conforms to JIS
- Contains a skin layer made of a thermoplastic polymer with a JIS-A hardness of 20 to 90 in K6301, and an olefin rubber, and has a flexural modulus of 1000k in JIS-K7203.
g/cm^2 or more, the core layer has a higher hardness than the skin layer, and the core layer contains a material that easily ruptures when the airbag starts operating. An air bag storage cover characterized by having a part attached thereto.