JPH09202202A - Thermoplastic elastomer composition for air bag cover and air bag - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic elastomer composition for providing a and obtaining an air bag cover having superior appearance, an advantage in terms of production costs owing to the need for no complicated production processes and enhanced development safety, and an air bag cover using the thermoplastic elastomer compsn. SOLUTION: A thermoplastic elastomer compsn. for air bag cover contains the following components (A)-(D): (A) an olefin-based resin; (B) ethylene-α- olefin-based copolymer rubber; (C) a hydrogenated aromatic vinyl-conjugate diene compd. block copolymer obtd. by hydrogenating a block copolymer consisting of a polymer block consisting of at least two aromatic vinyl compds. and a polymer block consisting of at least one conjugate diene compd. and having a number - average MW of 100,000 or more and (D) a plasticizer for rubber.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a thermoplastic elastomer composition for an airbag cover and an airbag cover. More specifically, the present invention is a thermoplastic elastomer composition which has an excellent appearance and is advantageous in manufacturing cost because it does not require a complicated manufacturing process, and can provide an airbag cover with improved safety during deployment. And an airbag cover using the thermoplastic elastomer composition.

[0002]

2. Description of the Related Art In recent years, automobiles equipped with airbags have been increasing in order to protect occupants of automobiles from the impact of a collision. The airbag is normally stored in the airbag cover, but when the impact at the time of collision is sensed, the airbag is inflated by the working gas, and the inflation pressure causes the airbag cover to break at a predetermined portion ( "Unfolded") and the airbag is inflated to protect the occupant. The airbag cover is usually made of synthetic resin. Here, as a requirement for the airbag, it is necessary to surely deploy the airbag at the time of operation (“deployment reliability”), and at the time of operation, the airbag cover is broken at a portion other than a predetermined portion and scattered as small fragments, The driver must not be injured by debris ("deployment safety"). Of course, it is also necessary to have excellent appearance and manufacturing cost.

By the way, Japanese Patent Laid-Open No. 52-116537 and Japanese Patent Laid-Open No. 4-314648 disclose airbags using a crosslinkable thermoplastic elastomer composition. However, the airbag obtained by this method has a problem in that it is inadequate in appearance and requires a two-step kneading process, which is disadvantageous in manufacturing cost.

As a method for solving the above problems, Japanese Patent Laid-Open No. 3-258635 discloses an airbag using a non-crosslinking type olefinic thermoplastic elastomer composition. However, there is a problem that the airbag obtained by this method is insufficient in terms of deployment safety.

Generally, an air bag cover has a complicated shape, and an injection molded product has many weld lines. An air bag cover made of a material having a low weld strength has a risk of breaking from the weld during a deployment test and scattering fragments. Therefore, a material having a high tensile elongation in the weld portion is desirable for the air bag cover material.

[0006]

In view of the above situation, the problem to be solved by the present invention is advantageous in terms of manufacturing cost because it has an excellent appearance and does not require a complicated manufacturing process.
In addition, a welded part of a molded article has a high tensile elongation, and a thermoplastic elastomer composition capable of providing an airbag cover having improved deployment safety and an airbag cover using the thermoplastic elastomer composition are provided. .

[0007]

That is, one invention of the present invention relates to a thermoplastic elastomer composition for an airbag cover, which contains the following components (A) to (D). (A): Olefin-based resin (B): Ethylene-α-olefin-based copolymer rubber (C): Polymer composed of a polymer block composed of at least two aromatic vinyl compounds and at least one conjugated diene compound Hydrogenated aromatic vinyl-conjugated diene compound block copolymer having a number average molecular weight of 100,000 or more obtained by hydrogenating a block copolymer composed of a block (D): a plasticizer for rubber

Another aspect of the present invention relates to an airbag cover obtained by using the above-mentioned thermoplastic elastomer composition.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The component (A) of the present invention is an olefin resin. The olefin resin is preferably polypropylene or a copolymer of propylene and an α-olefin having 2 or more carbon atoms. Α- with 2 or more carbon atoms
Examples of the olefin include ethylene, 1-butene,
1-pentene, 3-methyl-1-butene, 1-hexene, 1-decene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-octene and the like can be mentioned, preferably polypropylene, These may be of any type of random, block and homo. The melt flow rate of the olefin resin is usually 0.1 to 100 g / 10 minutes, preferably 1 to 70.
It is in the range of g / 10 minutes.

The content of (A) in the thermoplastic elastomer composition of the present invention is preferably 15 to 70% by weight, more preferably 25 to 65% by weight.
If the content of (A) is too small, the tensile strength may decrease, while if the content of (A) is too large, the impact properties may deteriorate.

The component (B) of the present invention is an ethylene-α-olefin copolymer rubber. Examples of ethylene-α-olefin copolymer rubbers include ethylene-α-olefin copolymer rubbers and ethylene-α-olefin-non-conjugated diene copolymer rubbers. Also,
An oil-extended ethylene-α-olefin copolymer rubber containing the component (D) oil may be used.

Examples of the α-olefin in the ethylene-α-olefin-non-conjugated diene copolymer rubber include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, Examples thereof include 1-decene, and among them, propylene is preferable.
Further, as the non-conjugated diene, for example, 1.4-hexadiene, 1.6-octadiene, 2-methyl-1.5-
Hexadiene, 6-methyl-1,5-heptadiene, 7
Chain non-conjugated dienes such as -methyl-1-6-octadiene; cyclohexadiene, dicyclopentadiene, methyltetrahydroindene, 5-vinylnorbornene,
5-ethylidene-2-norbornene, 5-methylene-2
Cyclic non-conjugated dienes such as -norbornene, 5-isopropylidene-2-norbornene, 6-chloromethyl-5-isopropenyl-2-norbornene; 2,3-diisopropylidene-5-norbornene, 2-ethylidene-3
Trienes such as isopropylidene-5-norbornene, 2-propenyl-2,2-norbornadiene, 1,3,7-octatriene, 1,4,9-decatriene are mentioned, and among them, 5-ethylidene-2- Norbornene or dicyclopentadiene are preferred.

Ratio of ethylene / α-olefin in ethylene-α-olefin copolymer rubber (molar ratio)
Is usually 1 / (0.1 to 1).

When the ethylene-α-olefin-non-conjugated diene copolymer rubber is used, the content of the non-conjugated diene is
The iodine value is usually 5 to 20.

As a preferred specific example of the ethylene-α-olefin copolymer rubber, the propylene content is 10 to 4
Mention may be made of 0% by weight, preferably 20 to 35% by weight of ethylene-propylene copolymer rubber.

Ethylene-α-olefin copolymer rubber
Is the Mooney viscosity at 100 ° C. (ML _{1 + 4}100 ° C) is 5
To 150 are preferable, and 10 to 10 are more preferable.
0. If the Mooney viscosity is too low, the mechanical strength will increase.
On the other hand, the Mooney viscosity is too high.
The appearance of the shaped product is impaired or injection molding becomes difficult.
There is. In addition, when oil-extended rubber is used as (B)
The Mooney viscosity of (B) is based on the value including the extender oil.
You.

The content of (B) in the thermoplastic elastomer composition of the present invention is preferably 10 to 45% by weight. If the content of (B) is too small, flow marks may occur and the appearance of the molded product may be significantly deteriorated. On the other hand, if the content of (B) is too large, the orientation of the rubber phase may occur and the injection molded product may be formed. The decrease in tensile elongation of the well portion may occur.

The component (C) of the present invention is obtained by hydrogenating a block copolymer comprising a polymer block composed of at least two aromatic vinyl compounds and a polymer block composed of at least one conjugated diene compound. The resulting hydrogenated aromatic vinyl-conjugated diene compound block copolymer having a number average molecular weight of 100,000 or more, for example, AB-
A, (AB) _n [n-AB diblocks are coupled at the B end] and the like. Here, the polymer block B is a polymer block obtained by hydrogenating a non-conjugated diene, and A is a polymer block made of an aromatic vinyl compound. As the aromatic vinyl compound (C), styrene is preferable from the industrial viewpoint. From the industrial viewpoint, butadiene or isoprene is preferable as the conjugated diene compound (C).

The number average molecular weight of the hydrogenated aromatic vinyl-conjugated diene compound block of the component (C) of the present invention must be 100,000 or more. Hydrogenated aromatic vinyl-
When the molecular weight of the conjugated diene compound block is lower than 100,000, TP composed of (A) + (B) + (C) + (D)
Since the mechanical strength of E may decrease and the melt viscosity of (C) decreases, ethylene-
The effect of suppressing the orientation of the α-olefin copolymer rubber decreases, and the tensile elongation of the weld portion of TPE may decrease.

The weight ratio of aromatic vinyl compound / conjugated diene compound (C) is preferably 20/80 to 50/50. Too little aromatic vinyl compound (too much conjugated diene compound) may reduce the mechanical strength, while too much aromatic vinyl compound (too little conjugated diene compound) results in high elastic modulus and The impact properties of the plastic elastomer may deteriorate. The content of the aromatic compound in the hydrogenated aromatic vinyl-conjugated diene compound block copolymer is more preferably in the range of 25 to 38% by weight.

The content of (C) in the thermoplastic elastomer composition of the present invention is preferably 10 to 40% by weight. If the content of (C) is too small, the effect of suppressing the orientation of the rubber becomes insufficient, and the tensile elongation of the weld portion of the thermoplastic elastomer may be low, while the content of (C) is too large. If so, the fluidity is lowered, the moldability is largely lowered, and flow marks may appear on the molded product to deteriorate the appearance.

The component (D) of the present invention is a plasticizer for rubber. Specific examples of (D) include paraffin oils, silicone oils, polyisobutylene oils, etc. Among them, aroma compounds and naphthene compounds are excluded as much as possible from the viewpoint of heat resistance and weather resistance. Paraffinic oil is preferred.

The content of (D) in the thermoplastic elastomer composition of the present invention is preferably 3 to 25% by weight, more preferably 3 to 18% by weight. When the content of (D) is too small, the hydrogenated aromatic vinyl-conjugated diene compound block having a high melt viscosity of (C) becomes insufficiently dispersed, resulting in deterioration of impact properties and generation of spots on the surface of the molded article. On the other hand, if the content of (D) is excessive, the impact resistance at low temperatures may be reduced.

Further, the thermoplastic elastomer composition of the present invention contains, in addition to the above-mentioned components, if necessary, an antioxidant, a heat stabilizer, an ultraviolet absorber, a lubricant, an antistatic agent, a pigment and a filler. A flame retardant may be added.

As a method for obtaining the thermoplastic elastomer composition of the present invention, melt kneading with a twin-screw extruder, a Banbury mixer or the like can be mentioned.

The thermoplastic elastomer composition of the present invention comprises:
It can be obtained by so-called simple blending without requiring a complicated manufacturing process such as dynamic crosslinking, and is advantageous from the viewpoint of manufacturing cost.

The thermoplastic elastomer composition of the present invention comprises:
It is processed into an airbag by utilizing the excellent characteristics as described above. The airbag has excellent appearance and safety when deployed.

[0028]

The present invention will be described in more detail with reference to the following examples.

[I] Raw Materials The following raw materials were used to obtain the compositions of Examples and Comparative Examples.

(A) Olefin resin A-1: 230 ° C., MI of 2.16 kg load is 65 (g
/ 10 min) block polypropylene A-2: 230 ° C., MI of 2.16 kg load is 60 (g
/ 10 min) and a melting point of 141 ° C. Random polypropylene A-3: 230 ° C., MI of 2.16 kg load is 23 (g
Homopolypropylene A-4: 230 ° C., MI under 2.16 kg load is 2.5
(G / 10 min) homopolypropylene A-5: 190 ° C., MI under load of 2.16 kg is 5.3,
High density polyethylene with a specific gravity of 0.968

(B) Ethylene-α-olefin Copolymerization
Body rubber B-1: Mooney viscosity (ML _{1 + 4} 121 ° C.) 33, ethylene propylene rubber with a propylene content of 27% B-2: Mooney viscosity (ML _{1 + 4} 121 ° C.) 68, propylene content 31 % Ethylene propylene rubber

(C) Hydrogenated aromatic vinyl-conjugated diene
Compound block copolymer C-1: Hydrogenated styrene-butadiene-styrene block copolymer (SEBS) Shell Chemical Co., Ltd. Kraton G1651 (molecular weight 174,000, styrene content 33%) C-2: SEBS Shell Chemical Co., Ltd. Clayton G16
50 (molecular weight 70,000, styrene content 30%) C-3: SEBS Shell Chemical Co., Ltd., Kraton G16
57 (molecular weight 80,000, styrene content 13%) C-4: hydrogenated styrene-isoprene-styrene block copolymer (SEPS) molecular weight 200,000, styrene content 35%

(D) Plasticizer D-1 for Rubber : Mineral Oil Paraffin Softener Diana Process Oil PW-380 manufactured by Idemitsu Kosan Co., Ltd.

[II] Additive Formulation Hereinafter, in any of the Examples and Comparative Examples, the additive formulation is constant as follows. Antioxidant: Sumilizer BP-101 (manufactured by Sumitomo Chemical Co., Ltd.) 0.2% by weight Light stabilizer: Sanol LS770 (manufactured by Ciba Geigy) 0.05% by weight based on 100 parts by weight of resin part (including oil) 〃: Sumisorb 300 (Sumitomo Chemical Co., Ltd.) 0.1% by weight Lubricant: Oleic acid amide 0.1% by weight

[III] Evaluation / Measurement Method For the obtained composition, the cylinder temperature was 220 ° C.,
A test piece was prepared by injection molding at a mold temperature of 50 ° C., and the physical properties were evaluated.

Various properties described in the examples and comparative examples were measured by the following methods. (1) MI: JIS K7112 (temperature 230 ° C,
Load 2.16 kgf) (2) Hardness: ASTM D2240 (3) Bending test: JIS K7203 (4) Tensile test: JIS K6301 (No. 3 dumbbell was used, and a test was performed at a pulling speed of 200 (mm / min). (5) Izod impact test: (ASTM D256 test piece had a thickness of 12 mm and was tested with a notch.)

(6) Weld Part Tensile Test A flat plate having a facing weld at the center is prepared by injection molding using a mold having two facing gates. A JIS No. 3 tensile test piece is punched out from the flat plate with a dumbbell so that the weld line is located at the center between the marked lines. The tensile test piece was tested by the method of (3) tensile test.

(7) Appearance of Molded Product A flat plate having a mirror surface size of 150 × 90 mm was molded with a one-point standard gate, and the appearance of the molded product was visually judged.

(8) Air bag cover deployment test A driver seat type or passenger side type air bag cover was molded. Attach the air bag and the air bag cover to the mounting metal fittings, further attach the gas generator, put the air bag device in the constant temperature air bath at the deployment temperature (-40 ℃, room temperature, 90 ℃), and then stabilize it at the set temperature. After leaving it for 1 hour, the air bag was taken out and mounted on a pedestal for a quick deployment test. The deployability of the air bag cover was considered good if the air bag cover was torn at the planned breakage portion and the air bag was deployed without generating a fragment.

Example 1 60% by weight of block PP of A-1 and EPR19 of B-1
% Of SEBS, 15.5% by weight of SEBS of C-1, 5.5% by weight of oil of D-1 and additives were kneaded with a Banbury mixer at 170 to 200 [deg.] C., and then pelletized using an extruder. The obtained composition was injection-molded to prepare a test piece, and the physical properties were evaluated. The tensile elongation of the weld portion exceeded 200%, and the appearance of the molded product was good.

Example 2 43% by weight of homo PP of A-4, the same EPR as in Example 1,
The same procedure as in Example 1 was carried out except that SEBS and oil were mixed in the amounts shown in Table 1. The tensile elongation of the weld is 2
The content was more than 00% and the appearance of the molded product was good.

Example 3 30% by weight of random PP of A-2, the same EP as in Example 1
The same procedure as in Example 1 was carried out except that the amounts of R, SEBS and oil were changed as shown in Table 1. The tensile elongation of the weld portion exceeded 200%, and the appearance of the molded product was good.

Example 4 30% by weight of random PP of A-2, HDPE5 of A-5
The same procedure as in Example 1 was carried out except that the weight percent, EPR, SEBS, and oil as in Example 1 were changed to the compounding amounts shown in Table 1. The tensile elongation of the weld portion exceeded 200%, and the appearance of the molded product was good.

Comparative Example 1 45% by weight of block PP of A-1 and EPR55 of B-1
% By weight and additives in Banbury mixer 170-2
After kneading at 00 ° C, pellets were prepared using an extruder. The obtained composition was injection-molded to prepare a test piece, and the physical properties were evaluated. The tensile elongation of the weld portion of the material was a low value of 44%. A deployment test was conducted with a passenger seat type airbag cover, but it was 90 ° C and -40 ° C.
In each case, fragments were scattered.

Comparative Example 2 45% by weight of block PP of A-1 and HDPE5 of A-5
% By weight, 50% by weight of EPR of B-1 and the additive were kneaded with a twin-screw extruder having a cylinder temperature of 220 ° C. to prepare pellets. The obtained composition was injection-molded to prepare a test piece, and the physical properties were evaluated. The tensile elongation of the weld portion of the material was a low value of 70%. A deployment test was conducted with a driver's seat type airbag cover. In the test at 90 ° C., the rupture progressed to a place other than the expected cleavage portion and the expansion was poor.

Comparative Example 3 8% by weight of SEBS of C-1 and the same block P as in Example 1
The same procedure as in Comparative Example 2 was carried out except that P and EPR were changed to the compounding amounts shown in Table 3. Tensile elongation of weld of material is 2
It was a low value of 0%. Since the composition did not contain the oil as the component (D), SEBS having a high melt viscosity caused poor dispersion, and the appearance of the molded article was poor due to the appearance of lumps.

Comparative Example 4 25% by weight of homo PP of A-3, same SEB as in Example 1
The same procedure as in Example 1 was carried out except that the amounts of S and oil were changed to those shown in Table 3. Since the composition did not contain the EPR of the component (B) and contained a large amount of oil, the molded product had low gloss and uneven gloss, resulting in a poor appearance.

Example 5 Example 5 was carried out in the same manner as in Example 1 except that the same amounts of the blocks PP, EPR, SEBS and oil as in Example 1 were used. Both the 90 ° C and -40 ° C deployment tests with the driver's seat type air bag cover were good.

Comparative Example 5 The procedure of Example 5 was repeated except that SE-2 of C-2 was used. The tensile elongation of the weld portion of the material was a low value of 75%.

Comparative Example 6 The same procedure as in Example 5 was carried out except that SEBS of C-3 was used. The tensile elongation of the weld portion of the material was a low value of 80%.

Example 6 Example 6 was carried out in the same manner as in Example 5 except that the same amounts of the blocks PP, EPR, SEBS and oil as in Example 5 were used. 90 ° C with passenger seat type airbag cover
And the development test at -40 ° C was also good.

Example 7 The same procedure as in Example 5 was carried out except that 17 wt% of SEPS of C-4, the same block PP, EPR and oil as those in Example 5 were used in the blending amounts shown in Table 5. The tensile elongation of the weld portion exceeded 200%, and the appearance of the molded product was good.

Conditions and results are shown in Tables 1 to 6. The following can be seen from the results. All the examples satisfying the requirements of the invention show satisfactory results. On the other hand, Comparative Examples lacking the requirements of the present invention are unsatisfactory as follows. That is, Comparative Examples 1 and 2 which did not use (C) and (D), which are the essential components of the present invention, were inferior in tensile elongation and development test results of the weld part, and Comparative Examples which did not use (D). 3 is inferior in tensile elongation of the weld part and appearance of the molded product, Comparative Example 4 in which (B) is not used is inferior in appearance of the molded product, and Comparative Example 5 and Comparative Example 6 in which (C) whose molecular weight is too small are used are welds. The tensile elongation of the part is inferior. It is known that the tensile elongation is a property closely related to deployment safety, and inferior tensile elongation of the weld portion means inferior deployment safety.

[0054]

[Table 1] −−−−−−−−−−−−−−−−−−−−−−−−−−−− Example 1 2 3 4 Formulation (wt%) (A) Type A- 1 A-4 A-2 A-2 + A-5 ^{* 1} Quantity 60.0 43.0 30.0 43.0 (B) Type B-1 B-1 B-1 B-1 Quantity 19.0 27.0 39.0 30.0 (C) Type C-1 C -1 C-1 C-1 Quantity 15.5 22.0 21.0 18.5 (D) Type D-1 D-1 D-1 D-1 Quantity 5.5 8.0 10.0 8.5 −−−−−−−−−−−−−−−−− ------------------ * 1 (A-2) 38% by weight and (A-5) 5% by weight

[0055]

[Table 2] −−−−−−−−−−−−−−−−−−−−−−−−−−−− Actual Example 1 2 3 4 Evaluation MI g / 10min 11 1 2.5 4.3 Hardness Shore A--90 95 Shore D 60 51 36 45 Flexural modulus kgf / cm ² 5100 3800 930 1800 Tensile strength kgf / cm ² 130 290 70 100 Tensile elongation% 390 380 480 490 Izod impact strength (-50 ℃) kg-cm / cm 6 14 73 34 Weld tensile strength kgf / cm ² 110 74 50 77 Tensile elongation% 270 250 380 430 Appearance of molded product ○ ○ ○ ○ −−−−−−−−−−−−−−−−−− −−−−−−−−−−

[0056]

[Table 3] −−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 1 2 3 4 Formulation (wt%) (A) Type A- 1 A-1 + A-5 ^{* 2} A-1 A-3 Quantity 45.0 50.0 50.0 25.0 (B) type B-2 B-1 B-1-Quantity 55.0 50.0 42.0 0 (C) type--C-1 C -1 amount 0 0 8.0 37.5 (D) type---D-1 amount 0 0 0 37.5 −−−−−−−−−−−−−−−−−−−−−−−−−−−− * 2 (A-1) 45% by weight and (A-5) 5% by weight

[0057]

[Table 4] −−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparison Example 1 2 3 4 Evaluation MI g / 10min 6.2 12 7.7 4.6 Hardness Shore A 93 94 96 83 Shore D 47 49 53 30 Flexural modulus kgf / cm ² 3400 3300 3900 920 Tensile strength kgf / cm ² 88 86 100 150 Tensile elongation% 370 210 260 680 Izod impact strength (-50 ° C) kg-cm / cm 80 38 16 9 Weld tensile strength kgf / cm ² 65 65 86 175 Tensile elongation% 44 70 20 730 Appearance of molded product ○ ○ × × Development test ^{* 3} 90 ℃ × ×--(Assist) (Luck) -40 ℃ × ○--(Assistance) (Luck) ----------------------------------------- * 3 Deployment test (Assistance): Passenger seat type (Luck) Driver's seat type

[0058]

[Table 5] ------------------ Example-Comparative Example Comparative Example Example Example 5 5 6 6 7 Blend (wt%) (A) Type A-1 A-1 A-1 A-1 A-1 Amount 43.0 43.0 43.0 43.0 43.0 (B) Type B-1 B-1 B-1 B-1 B-1 Amount 28.0 28.0 28.0 32.0 32.0 (C) type C-1 C-2 C-3 C-1 C-4 amount 17.0 17.0 17.0 17.0 17.0 (D) type D-1 D-1 D-1 D-1 D-1 amount 12.0 12.0 12.0 8.0 8.0 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

[0059]

Table 6 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Example Comparative Example Comparative Example Comparative Example Example 5 5 6 6 7 Evaluation MI g / 10min 6.0 18.0 22.0 3.9 4.4 Hardness Shore A 96 94 92 94 96 Shore D 46 46 46 49 48 Flexural modulus kgf / cm ² 2400 2200 2100 2400 2400 Tensile strength kgf / cm ² 95 90 95 100 115 Tensile elongation % 430 390 410 460 540 Izod impact strength (-50 ° C) kg-cm / cm 5 25 20 48 89 Weld tensile strength kgf / cm ² 75 62 61 75 76 Tensile elongation% 350 75 80 300 310 Appearance of molded product ○ ○ ○ ○ ○ Deployment test 90 ℃ ○--○-(Luck) (Assistance) -40 ℃ ○--○-(Luck) (Assistance) −−−−−−−−−−−−−−-- −−−−−−−−−−−−−

[0060]

As described above, according to the present invention, it is possible to provide an airbag cover which has an excellent appearance and is advantageous in terms of manufacturing cost because it does not require a complicated manufacturing process and has improved deployment safety. A thermoplastic elastomer composition and an airbag cover using the thermoplastic elastomer composition can be provided.

Claims (11)

[Claims] 1. A thermoplastic elastomer composition for an airbag cover, which contains the following components (A) to (D). (A): Olefin-based resin (B): Ethylene-α-olefin-based copolymer rubber (C): Polymer composed of a polymer block composed of at least two aromatic vinyl compounds and at least one conjugated diene compound Hydrogenated aromatic vinyl-conjugated diene compound block copolymer having a number average molecular weight of 100,000 or more obtained by hydrogenating a block copolymer composed of a block (D): a plasticizer for rubber 2. The method according to claim 1, wherein (A) is polypropylene.
The thermoplastic elastomer composition as described in the above. 3. The thermoplastic elastomer composition according to claim 1, wherein (B) is an ethylene-α-olefin copolymer rubber or an ethylene-α-olefin-non-conjugated diene copolymer rubber. 4. The thermoplastic elastomer composition according to claim 1, wherein (B) is an ethylene-propylene copolymer rubber. 5. The thermoplastic elastomer composition according to claim 1, wherein the aromatic vinyl compound (C) is styrene. 6. The thermoplastic elastomer composition according to claim 1, wherein the conjugated diene compound (C) is butadiene or isoprene. 7. The thermoplastic elastomer composition according to claim 1, wherein the weight ratio (C) of the aromatic vinyl compound / conjugated diene compound is 20/80 to 50/50. 8. The thermoplastic elastomer composition according to claim 1, wherein (D) is a paraffinic oil. 9. The content of (A) is 15 to 70% by weight, the content of (B) is 10 to 45% by weight, and (C).
Is 10 to 40% by weight, and the content of (D) is 3 to 25% by weight (however, (A) + (B) + (C)
+ (D) = 100% by weight. ) The thermoplastic elastomer composition according to claim 1. 10. The thermoplastic elastomer composition according to claim 1, which is obtained by simply blending the components (A) to (D). 11. An airbag cover obtained by using the thermoplastic elastomer composition according to claim 1.