JP2002161178A - Automotive interior parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automotive interior part installed with an air bag having a good low temperature resistance as well as a good impact resistance, which is manufactured from a thermoplastic elastomer composition consisting of a polyolefin resin composition and specific hydrodiene copolymer as essential elements, wherein the interior part has fine flexibility and does not easily become whitened when it is bended, and the interior part has the outermost layer prepared by powder moulding which is low gloss when it is heated at temperatures ranging from 80 deg.C to below the melting point of polyolefin. SOLUTION: The automotive interior part installed with an air bag which has the outermost layer comprising powder-base moulding consisting of a thermoplastic elastomer composition containing (I) 100 pts.wt. of polyolefin and (II) 10 to 1000 pts.wt. of hydrodiene copolymer. The automotive part is also installed with an air bag.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile interior part.

[0002]

2. Description of the Related Art Conventionally, a sheet-like molded article having a complex uneven pattern such as a grain or a stitch on the surface has been used as a skin material for an automobile interior part or the like. By the powder molding method, it is possible to produce a molded article having a complicated shape such as an instrument panel having a sharp corner portion or a complicated meter visor portion and having excellent grain transferability. As such a powder compact, there has been proposed a powder compact obtained by powder-forming a powder obtained by pulverizing an olefin-based thermoplastic elastomer, which is a substitute for a conventional powder compact made of a vinyl chloride resin (for example, JP-A-5-1183 and JP-A-5-505
See No. 0 publication. ).

[0003] However, the powder compact obtained by such a method is harder than a powder compact made of a vinyl chloride resin and has a property of being easily whitened when bent. When the mold is removed from the mold after production or when the powder compact is preformed into a desired shape, the bent portion tends to whiten and appearance defects tend to occur. Did not.

[0004] Japanese Patent Application Laid-Open No. 7-82433 discloses that
A powder resin composition comprising a polyolefin resin and a hydrogenated styrene-butadiene rubber having a styrene content of 20% by weight or less is described. However, in the powder molded product obtained by powder molding the powder resin composition, although the bent portion does not whiten when bent,
When heated at a temperature of about 0 ° C. to a temperature lower than the melting point of the polyolefin resin, the resin emits gloss. Therefore, when used as a skin material of an interior material of an automobile, there is a problem in that appearance is poor, and it is not practical (in the summer season). It is known that when an automobile is stored outdoors, the temperature of the surface of the interior material of the automobile such as an instrument panel rises to about 80 to 120 ° C.).

Further, from the viewpoint of design, automobile interior parts such as an instrument panel and a steering wheel having a complicated shape and a built-in airbag are strongly demanded from the market.

However, in an automobile interior part having a conventional powder molded body made of a vinyl chloride resin composition as an outermost layer and having an airbag built therein, the airbag mechanism is operated at a low temperature of about -20 ° C or less. When activated, the outermost layer of the vinyl chloride resin composition has poor cold impact resistance, and there is a risk that a driver or a passenger may be injured by fragments of the vinyl chloride resin composition. For this reason, automobile interior parts in which an airbag having a powder molded body made of a vinyl chloride-based resin composition in the outermost layer is not widely used.

[0007] Furthermore, there are global environmental problems and the like, and there has been a demand for an automobile interior part in which an airbag having a thermoplastic elastomer composition in the outermost layer instead of the vinyl chloride resin composition is built in.

[0008]

Under these circumstances, an object of the present invention is to provide a thermoplastic elastomer composition containing a polyolefin resin and a specific hydrogenated diene copolymer as essential components. It has excellent flexibility, hardly whitens the bent part when it is bent, and has a powder molded body in the outermost layer that does not emit gloss when heated at a temperature of about 80 ° C. to a temperature lower than the melting point of the polyolefin resin. Another object of the present invention is to provide an automobile interior part having a built-in airbag excellent in performance.

[0009]

That is, the first invention of the present invention comprises the following (I) 100 parts by weight and (II) 10 parts by weight.
The present invention relates to an automobile interior part in which an airbag is incorporated, having an outermost layer of a powder molded body made of a thermoplastic elastomer composition containing up to 1000 parts by weight. (I): Polyolefin resin (II): Hydrogenated diene copolymer satisfying all of the following conditions: Hydrogenated diene copolymer contains the following structural units (A) and (B) (A): Polymer block of vinyl aromatic compound (B): At least one type of block selected from the following (B1), (B2) and (B3) (B1): Random copolymer of vinyl aromatic compound and conjugated diene A block obtained by hydrogenating a polymer block (B2): a block comprising a vinyl aromatic compound and a conjugated diene, and a block obtained by hydrogenating a tapered block in which a vinyl aromatic compound is gradually increased (B3): a conjugated diene polymer Block obtained by hydrogenating a block: Total vinyl aromatic compound unit content (T) contained in the hydrogenated diene copolymer is 10 to 18% by weight: Hydrogenated diene copolymer The ratio (S: percentage) of the vinyl aromatic compound unit content of the above (A) to the total vinyl aromatic compound unit content in the body is 3% or more: water in the hydrogenated diene copolymer The ratio (V: percentage) of the number of hydrogenated conjugated diene units having a side chain having 2 or more carbon atoms to the total number of added conjugated diene units is more than 60%: the above in the hydrogenated diene copolymer The relationship between (T), (S) and (V) above satisfies the following formula (1): V ≦ 0.375 × S + 1.25 × T + 40 (1): hydrogenated diene copolymer 80% or more of the double bonds of the conjugated diene unit in the union are hydrogenated: the number average molecular weight of the hydrogenated diene copolymer is 50,000 to 40
The second aspect of the present invention relates to an automobile interior part in which a foamed layer is lined on an inner surface of the powder compact of the first aspect. A third aspect of the present invention relates to an integrated automobile interior part designed so that the airbag deployment portion of the automobile interior part of the first invention cannot be determined from the outside. A fourth aspect of the present invention relates to an integrated automobile interior part designed so that an airbag deployment portion of the automobile interior part of the first invention can be determined from the outside.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The component (I) of the present invention is a polyolefin resin and is at least one selected from olefin homopolymers and copolymers having high crystallinity. As the olefin, ethylene, propylene,
Examples thereof include olefins having 2 to 8 carbon atoms such as 1-butene, 1-hexene and 1-octene. Examples of (I) include polyethylene, polypropylene, poly (1-butene), a copolymer of propylene and ethylene, and a copolymer of propylene and another α-olefin (eg, 1-butene). can give. (I) is propylene-
In the case of an ethylene copolymer resin or a propylene-1-butene copolymer resin, the thermoplastic elastomer composition of the present invention is preferable in that a molded article having excellent heat resistance and flexibility can be obtained. The crystallinity of (I) needs to be 50% or more, and preferably 60% or more. Here, the crystallinity is determined by an X-ray structure analysis method.

In addition, a copolymer obtained by copolymerizing two or more monomers selected from ethylene and an α-olefin having 3 to 8 carbon atoms in two or more steps can also be used. For example, a copolymer obtained by homopolymerizing propylene in the first step and copolymerizing propylene with ethylene or an α-olefin other than propylene in the second step can be used. In addition, from the viewpoint of the strength of the molded body obtained by the powder molding method, JIS K-
The melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kgf according to 7210 is usually 20 to
500 g / 10 min, preferably 50 to 300 g / 10
Min, particularly preferably in the range of 100 to 300 g / 10 min. In addition, as (I), a highly fluidized product obtained by decomposition using an organic peroxide or the like can also be used.

The component (II) of the present invention is a hydrogenated diene copolymer which satisfies all of the above conditions. (I
Examples of conjugated dienes used in the production of I) include, for example, 1,3-butadiene, isoprene (2-methyl-
1,3-butadiene), 1,3-pentadiene, 2,3
-Dimethyl-1,3-butadiene, 2-methyl-1,3
And conjugated dienes having 4 to 8 carbon atoms such as pentadiene. Above all, 1,3-butadiene is preferred in that the automobile interior part of the present invention having a powder compact having excellent cold impact resistance in the outermost layer can be obtained.

The vinyl aromatic compound has one of the vinyl groups.
The 2- or 3-position may be substituted with an alkyl group such as a methyl group. Examples of vinyl aromatic compounds include styrene, p-methylstyrene, α-methylstyrene, t-
Examples thereof include vinyl aromatic compounds having 8 to 12 carbon atoms, such as butylstyrene, divinylbenzene, and vinylpyridine. Among them, styrene is preferably used from an industrial viewpoint.

(II) is a hydrogenated diene copolymer containing the following structural units (A) and (B). (A): vinyl aromatic compound polymer block (B): at least one type of block selected from the following (B1), (B2) and (B3) (B1): random copolymerization of vinyl aromatic compound and conjugated diene Block (B2): a block formed by hydrogenation of a vinyl aromatic compound and a conjugated diene, and a block formed by hydrogenating a tapered block in which a vinyl aromatic compound is gradually increased (B3): a conjugated diene polymer block Is hydrogenated block

(II) is usually represented by the general formula [(A)-(B)]
n, [(A)-(B)] n- (A), [(B)-
(A)] n- (B) (where n is an integer of 1 or more;
When there are a plurality of (A) and (B), each of the plurality of (A) and (B) may be the same or different. ), For example, [(A)-(B
1)] n- (A), [(A)-(B2)] n- (A),
Or [(A)-(B3)] n- (A) (where n is an integer of 1 or more and repeating units (A), (B1) and (B2)
And (B3) may be the same or different. And hydrogenated diene copolymers represented by

Among them, (A)-(B1)-(A),
(A)-(B2)-(A) or (A)-(B3)-
The hydrogenated diene copolymer represented by (A) is preferable in that it is industrially easy to produce, and is preferably a hydrogenated product of a styrene-butadiene / styrene-styrene copolymer or a water-soluble styrene-butadiene-styrene copolymer. Hydrogenated product of styrene-isoprene-styrene-styrene copolymer, styrene-
Hydrogenated isoprene-styrene copolymers are preferred in that they can be industrially easily produced. In particular, a hydrogenated product of a styrene-butadiene-styrene copolymer is obtained, and the automobile interior part of the present invention having a powder compact having excellent strength and cold shock resistance in the outermost layer is obtained, and the strength of the obtained powder compact is obtained. Is the ratio of the number of hydrogenated conjugated diene units having side chains having 2 or more carbon atoms to the number of hydrogenated conjugated diene units of the hydrogenated diene copolymer (described later) (V: percentage). This is preferable in that even if there is a subtle “shake”, it is hardly affected. Note that "-" indicates a boundary between blocks, and "-" indicates that two or more compounds are used in combination in one block.

The total vinyl aromatic compound unit content in (II) must be in the range of 10 to 18% by weight (conditions), and is preferably in the range of 12 to 17% by weight. Total vinyl aromatic compound unit content is 18
If the amount is more than 10% by weight, the outermost layer of the thermoplastic elastomer composition tends to be hard.
On the other hand, when the total content of the vinyl aromatic compound units is less than 10% by weight, there is a problem that the outermost layer powder molded product of the automobile interior part of the present invention has tackiness. The total vinyl aromatic compound unit content was determined by using a solution of (II) such as carbon tetrachloride in ¹ H-N at a frequency of 90 MHz or more.
It can be determined by MR measurement.

The ratio (S: percentage) of the vinyl aromatic compound unit content of the vinyl aromatic compound polymer block (A) to the total vinyl aromatic compound unit content of (II) is as follows:
3% or more (condition) is required, and 30 to 1
It is preferably 00%, more preferably 50 to 100%. If the proportion is less than 3%, there is a problem that the powder molded body used for the obtained outermost layer has tackiness. The ratio was determined by using a solution of carbon tetrachloride (II) in a solution of ¹ H-
It can be determined by NMR measurement.

In (II), the ratio of the number of hydrogenated conjugated diene units having a side chain having 2 or more carbon atoms to the number of all hydrogenated conjugated diene units of the conjugated diene copolymer (V: percentage ) Needs to be 60% or more (conditions), and is preferably 60 to 85%, and particularly preferably 65 to 80%. The ratio is 60
%, The outermost powder compact of the automotive interior part of the present invention tends to be hard and inferior in feel. In addition, such a ratio can be obtained by a Morello method using infrared analysis.

The total vinyl aromatic compound unit content (T) in (II), the ratio of the vinyl aromatic compound unit content of the (A) vinyl aromatic compound polymer block to the total vinyl aromatic compound unit content (S : Percentage) and the ratio (V: percentage) of the number of hydrogenated conjugated diene units having a side chain having 2 or more carbon atoms to the number of all hydrogenated conjugated diene units of the hydrogenated diene copolymer. It is necessary that the relationship satisfy the following expression (1) (condition). V ≦ 0.375 × S + 1.25 × T + 40 (1) In the expression (1), when the value on the left side exceeds the value on the right side,
When the automobile interior part of the present invention is heated at a temperature of about 80 ° C. to less than the melting point of the polyolefin resin, there arises a problem that the outermost layer powder molded body of the automobile interior part of the present invention emits gloss.

In (II), it is necessary that 80% or more of the double bond of the conjugated diene unit is hydrogenated (condition), and 90% or more, particularly 96% or more is hydrogenated. preferable. When the degree of hydrogenation is less than 80%, there is a problem that the light resistance of the outermost powder compact of the automotive interior part of the present invention is reduced.

The (II) having a number average molecular weight of 50,000 to 400,000 (conditions) is necessary in order to obtain an automobile interior part having a powder molded body having excellent appearance and strength, and from 100,000 to 300,000. Is preferably within the range. When the number average molecular weight is less than 50,000, the powder molded product of the outermost layer of the automotive interior part of the present invention becomes tacky and has insufficient heat resistance and light resistance. If the number average molecular weight exceeds 400,000, the meltability of the thermoplastic elastomer composition is inferior, so that a powder molded product having sufficient appearance and strength cannot be obtained. The number average molecular weight is measured by a GPC method.

The melt flow rate (MFR) measured at 230 ° C. under a load of 2.16 kgf according to JIS K-7210 of (II) is preferably 1 to 200 g / 10 min, and more preferably 5 to 100 g / 10 min. Minutes
This is preferable in that an automobile interior part having a powder molded body having sufficient appearance and strength in the outermost layer can be obtained.

The compound (II) of the present invention may be modified with a functional group and has at least one functional group selected from an acid anhydride group, a carboxyl group, a hydroxyl group, an amino group, an isocyanate group and an epoxy group. Modified functional groups can also be used. When these are used, for example, when the obtained powder molded body is bonded to a polyurethane foam layer to produce a two-layer molded body or a multilayer molded body, it is possible to obtain an advantage that the adhesiveness is improved.

Such (II) is described in, for example,
JP-A-725512, JP-A-5-271325, JP-A-5-271327, JP-A-6-287365
Can be manufactured by the method described in Japanese Patent Application Publication No.

The thermoplastic elastomer composition used for producing the powder molded product, which is the outermost layer of the automobile interior parts of the present invention, comprises (III) in addition to the essential components (I) and (II). An ethylene-α-olefin-based copolymer may be contained. When containing (III), without reducing the powder moldability of the thermoplastic elastomer powder, and the whitening resistance of the portion bent when the molded body obtained by powder molding the powder is folded, 80
The present invention provides an automobile interior material having an outermost layer of a powder molded product which does not emit gloss when heated at a temperature of about 0 ° C. to less than the melting point of the polyolefin-based resin, and further has excellent cold impact resistance.

(III) The ethylene-α-olefin-based copolymer is a copolymer of ethylene and α-olefin, a copolymer of ethylene, α-olefin and non-conjugated diene, and has almost no crystallinity. A polymer having no or a crystallinity of less than 50%. Here, the crystallinity is determined by an X-ray structure analysis method. Examples of the α-olefin include α-olefins having 3 to 10 carbon atoms such as propylene, 1-butene, and 3-methyl-1-butene. Examples of the non-conjugated diene include dicyclopentadiene, 5-2ethylidene norbornene, 4-hexadiene, 1,5
And non-conjugated dienes having 5 to 15 carbon atoms such as -cyclooctadiene and 5-methylene-2-norbornene. Examples of (III) include ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-
Octene copolymer and ethylene-propylene-5-2-2
Ethylidene norbornene copolymer (hereinafter "EPDM")
Called. ). Such ethylene-α-
The olefin-based copolymer may be crosslinked.

The content of the α-olefin unit in (III) is preferably 5 to 40% by weight, more preferably 10 to 40% by weight.
It is in the range of 35% by weight, and the ethylene unit content is usually 60 to 95% by weight, preferably 65 to 90% by weight. The α-olefin unit content and the ethylene unit content can be determined by ¹³ C-NMR method, infrared absorption spectroscopy, or the like. In addition, from the viewpoint of the strength of the outermost powder compact of the automotive interior part of the present invention of the present invention, this ethylene-α-olefin copolymer, ASTM D-9,
The Mooney viscosity {ML _{1 + 4} (100 ° C.)} measured at 100 ° C. according to 27-57T is preferably from 10 to 350,
It is more preferably in the range of 15 to 300.

When (III) is used, the amount of (III) is
(I) not more than 250 parts by weight per 100 parts by weight;
Preferably it is 20 to 200 parts by weight. If the amount of (III) is excessive, the outermost layer of the powder molded article of the automotive interior part of the present invention may have a sticky feeling.

Further, the thermoplastic elastomer composition used for producing the powder molded body which is the outermost layer of the automobile interior parts includes, in addition to the essential components (I) and (II),
(IV) The above (III) as long as the effects of the present invention are not impaired.
Other styrene-based thermoplastic elastomers may be contained. Examples of (IV) include, for example, hydrogenated diene-based copolymers containing the same structural units (A) and (B) as described in (II) above, and hydrogenated vinyl aromatic compound-conjugated diene random copolymers. Things and the like. As (IV), the above (II)
As the hydrogenated diene copolymer containing the same structural units (A) and (B) as described above, the conditions described in (II) above
And hydrogenated diene copolymers which do not satisfy at least one of the above conditions.

For example, when the conditions are not satisfied and a hydrogenated diene copolymer satisfying and is used (when the relational expression of V> 0.375 × S + 1.25 × T + 40 is satisfied), The present invention provides an automobile interior part having an outermost layer of a powder molded product having an outermost layer having more excellent scratch resistance.

When a hydrogenated diene copolymer which does not satisfy the conditions is used (water having a side chain having 2 or more carbon atoms with respect to the total number of hydrogenated conjugated diene units in the hydrogenated diene copolymer) In the case of using a hydrogenated diene-based copolymer in which the ratio of the number of added conjugated diene units (V: percentage) is 60% or less), an automobile interior material having an outermost layer excellent in cold shock resistance is provided.

When (IV) is used, the amount of (IV) is
(I) not more than 250 parts by weight per 100 parts by weight;
Preferably it is 20 to 200 parts by weight. If the amount of (IV) is excessive, there is an adverse effect that a sticky feeling is produced in the outermost powder compact of the automotive interior part of the present invention.

The thermoplastic elastomer composition used for producing the powder molded product, which is the outermost layer of the automobile interior part of the present invention, comprises a hydrogenated conjugated diene polymer, natural rubber, butyl rubber, chloroprene rubber, epichloro rubber. Rubber polymers such as hydrin rubber and acrylic rubber, ethylene-acrylic acid copolymer, ethylene-vinyl acetate copolymer and saponified product thereof, ethylene-methyl methacrylate copolymer, ethylene-glycidyl methacrylate-vinyl acetate copolymer Other polymer components such as a polymer and an ethylene-glycidyl acrylate-vinyl acetate copolymer may be contained.

As the hydrogenated product of the conjugated diene polymer rubber,
Examples include hydrogenated polybutadiene and hydrogenated polyisoprene. The ratio (V: percentage) of the number of hydrogenated conjugated diene units having a side chain having 2 or more carbon atoms to the total number of hydrogenated conjugated diene units in these hydrogenated diene polymers may exceed 60%. The hydrogenated product of the conjugated diene polymer may be composed of two or more blocks having different ratios, although it is preferable from the viewpoint of the flexibility of the outermost layer powder compact. When a hydrogenated conjugated diene polymer is used, the amount thereof is (I) 10
The amount is 250 parts by weight or less, preferably 20 to 200 parts by weight with respect to 0 parts by weight. If the content is excessive, the outermost layer of the powder molded article of the automobile interior part of the present invention may have a sticky feeling.

The thermoplastic elastomer composition used in the powder molded product, which is the outermost layer of the automobile interior part of the present invention, comprises:
For example, mineral oil-based softeners, heat stabilizers such as phenol-based, sulfite-based, phenylalkane-based, phosphite-based, amine-based, and amide-based, weather-resistant stabilizers, antistatic agents, pigments, metallic soaps, waxes, Fungicides, antibacterial agents,
Various additives such as a filler may be contained.

When the thermoplastic elastomer composition used for the powder molded product, which is the outermost layer of the automobile interior part of the present invention, contains a mineral oil-based softening agent, the thermoplastic elastomer composition powder having excellent melting properties and flexibility. The automobile interior parts can be obtained.

When the thermoplastic elastomer composition used for the powder molded product, which is the outermost layer of the automobile interior part of the present invention, contains a pigment, the molding is hardly discolored even when wiped with an organic solvent such as hexane, benzene or toluene. You can get the body. Examples of pigments include organic pigments such as azo-based, phthalocyanine-based, sulene-based and dye lakes, oxides such as titanium oxide, molybdic acid chromate, selenium sulfide compounds, ferrocyanide compounds, and inorganic pigments such as carbon black. Used.

As the pigment, any of a liquid substance and a powdery substance can be used. When a powdery material is used, the primary particle size is preferably 300 nm or less from the viewpoint of uniformity of coloring. When a powdery pigment is used, a pigment supported on a carrier such as calcium carbonate, metal soap, or magnesium oxide can also be used. In this case, the primary particle size of the carrier is usually 10 μm or less, preferably 1 to 5 μm. In this case, the weight ratio of the powder pigment to the carrier is usually 20:80 to 80:20, preferably 2:80.
5:75 to 75:25.

The thermoplastic elastomer composition used in the powder molded product, which is the outermost layer of the automobile interior part of the present invention, comprises:
The above (I) and (II) are contained as essential components, and if necessary, at least one of (III) and (IV) is contained. The content of (II) is based on 100 parts by weight of (I).
It is necessary that (II) be contained in an amount of 10 to 1000 parts by weight, preferably 40 to 200 parts by weight.
When the content of (II) is less than 10 parts by weight based on 100 parts by weight of (I), the feel of the automotive interior material of the present invention is inferior, and the portion bent in the demolding step after powder molding becomes white. If it exceeds 1000 parts by weight,
In addition to the occurrence of tackiness in the powder molded body as the outermost layer of the automotive interior material of the present invention, heat resistance and light resistance are insufficient.

Powder which is the outermost layer of the automobile interior part of the present invention
After the thermoplastic elastomer composition used for the powder compact
Powder molding obtained by the mechanical grinding method described above
The complex dynamic viscosity of the composition at 250 ° C.
η^*(1) is 1.5 × 10^FiveMust be less than poise
And 1 × 10^Two~ 8 × 10^FourPoise range preferred
And 3 × 10^Two~ 5 × 10^FourPoise, especially 3x1
0^Two~ 1 × 10^FourIt is preferably within the range of poise. This
Where the complex dynamic viscosity η^*(Ω) means temperature 250 ° C, vibration
Storage modulus G '(ω) and loss modulus at frequency ω
G ″ (ω) and is calculated by the following equation (2).
Complex dynamic viscosity η^*(1) is ω = 1 radi
Complex dynamic viscosity in an / sec. η^*(Ω) = ｛[G '(ω)]^Two+ [G "(ω)]^Two｝^1/2
/ Ω (2) η ^*If (1) exceeds the above upper limit,
Poor melt fluidity of thermoplastic elastomer composition, powder
Shearing speed during molding such as molding method is usually 1 second^-1Below and low
It is difficult to manufacture molded products with high molding methods
Tend to be.

When the powder of the thermoplastic elastomer composition used for the powder molded product, which is the outermost layer of the automobile interior part of the present invention, is formed using a powder obtained by a mechanical pulverization method described later, the Newton viscosity index n is as follows. It is necessary to be 0.67 or less, preferably 0.01 to 0.1.
It is preferably in the range of 35, more preferably in the range of 0.03 to 0.25. Where Newtonian viscosity index n
By the following equation (3) using the complex dynamic viscosity eta ^* (1) Temperature 250 ° C., and the complex dynamic viscosity eta ^* (100) measured at a vibration frequency omega = 100 radian / sec and This is a calculated value. n = {logη ^* (1) −logη ^* (100)} / 2 (3) When the Newton viscosity index n exceeds the above-mentioned upper limit, the mechanical strength of the powder molded body that is the outermost layer of the automobile interior part of the present invention. Becomes lower.

When the thermoplastic elastomer composition used for the powder molded product, which is the outermost layer of the automobile interior parts of the present invention, is powder-formed into a powder produced by a strand cut method, a die face cut method or a solvent treatment method described below. , The complex dynamic viscosity at 250 ° C. of the composition, η
^* (1) is preferably 1 × 10 ^{2 to} 5 × 10 ⁴ poise, and more preferably 3 × 10 ² to 8 × 10 ³ poise. In this case, the Newton's viscosity index n needs to be 0.28 or less, preferably in the range of 0.01 to 0.20, and more preferably 0.02 to 0.20.
It is preferably in the range of 3 to 0.15.

As a method for obtaining the thermoplastic elastomer composition used for the powder molded body which is the outermost layer of the automobile interior part of the present invention, the following method can be exemplified. That is, at least one of (I) and (II), and (III) and (IV) blended as needed may be melt-kneaded. Alternatively, it can be produced by kneading or dynamically cross-linking all or some of the above-mentioned components and then kneading and kneading the unselected components. For example, a thermoplastic elastomer composition containing (I), (II), (III) and (IV), wherein (I) and / or (III) is intramolecularly and / or intermolecularly crosslinked, Usually, it can be produced by dynamically crosslinking (I) and (III), and further adding (II) and (IV) and kneading. Here, for kneading, a single-screw extruder, a twin-screw extruder, a kneader, a roll, or the like can be used. The above-mentioned various additives and various polymers are blended, for example, by using (I), (II), (III) or (IV) in which these additives are previously blended, or by kneading the above components. It can be performed by blending at the time of dynamic crosslinking.

The dynamic crosslinking of the kneaded mixture can be performed, for example, by kneading the kneaded mixture and a crosslinking agent under heating. As the crosslinking agent, usually, 2,5-dimethyl-2,5-di (tert-butylperoxyno) is used.
Organic peroxides such as hexane and dicumyl peroxide are used. The crosslinking agent is usually at most 1 part by weight, preferably at most 0.1 part by weight, per 100 parts by weight of the total of at least one of (I) and (II) and optionally (III) and (IV). It is used in an amount of 1 to 0.8 part by weight, more preferably 0.2 to 0.6 part by weight. When using an organic peroxide as a cross-linking agent, when performing dynamic cross-linking in the presence of a cross-linking auxiliary such as a bismaleimide compound, an automobile interior part having a powder molded body having excellent heat resistance in the outermost layer can be obtained. The resulting thermoplastic elastomer composition can be obtained. In this case, the amount of organic peroxide used is
(I) and (II) and optionally blended (II
Usually, 0.8 parts per 100 parts by weight of the total of the components to be crosslinked among at least one of I) and (IV)
Parts by weight or less, preferably 0.2 to 0.8 parts by weight, more preferably 0.4 to 0.6 parts by weight.

The amount of the crosslinking aid used is at least one of the components to be crosslinked among at least one of (I) and (II), and (III) and (IV) if necessary.
Usually, 1.5 parts by weight or less, preferably 0.2 to 1 part by weight, more preferably 0.4 to 0.8 part by weight per 100 parts by weight.
It is in the range of parts by weight. The crosslinking aid is preferably added before the addition of the crosslinking agent, and is usually added when the components to be crosslinked are preliminarily kneaded.

The crosslinking of at least one of (I) and (II) and (III) and (IV) used as required comprises a component to be crosslinked, a crosslinking agent, and if necessary, Further, the crosslinking aid is heated with a single-screw extruder or a twin-screw extruder while heating, for example, 150 to
It can be performed by kneading in a temperature range of 250 ° C. It is also possible to carry out crosslinking by a method such as sulfur crosslinking.

These additives and other polymer components are:
(I) and (II) and optionally used (II
It may be used by being contained in advance in at least one of I) and (IV), or may be blended by kneading or the like during or after the above-mentioned kneading or dynamic crosslinking.
When a mineral oil-based softening agent is used, if the oil-extended ethylene-α-olefin-based copolymer in which the mineral oil-based softening agent is previously contained in (III) is used, the above kneading and dynamic crosslinking can be easily performed. It can be carried out.

In order to produce a thermoplastic elastomer composition which satisfies the physical properties indicated by the above-mentioned complex dynamic viscosity and Newtonian viscosity index, the above-mentioned degree of kneading and dynamic crosslinking, the thermoplastic elastomer composition And the amount of each component constituting the above, the types and amounts of the crosslinking agent and the crosslinking assistant in the dynamic crosslinking, the types of the additives, and the amounts of the additives are appropriately selected. Among them, the shear rate in kneading and dynamic crosslinking has a large effect on the above physical properties, and the shear rate is 1
It is preferred that kneading and dynamic crosslinking be performed in 10 ³ seconds ^-1 or more.

The powder of the thermoplastic elastomer composition used for producing the powder molded product which is the outermost layer of the automobile interior parts of the present invention is obtained by mechanically pulverizing the thermoplastic elastomer composition obtained by the above-mentioned method. Or a strand cut method, a die face cut method, or a solvent treatment method.

As a method of mechanically pulverizing such a thermoplastic elastomer composition, there is a freeze pulverization method or a normal temperature pulverization method. The freeze-pulverization method comprises the step of bringing the thermoplastic elastomer composition below its glass transition temperature, preferably -70.
C. or lower, more preferably -90.degree. C. or lower, and pulverization while maintaining the cooling state. It is also possible to pulverize the thermoplastic elastomer composition at a temperature higher than its glass transition temperature (normal temperature pulverization method), but the resulting pulverized product has an irregular particle size, which tends to make powder molding difficult. It is in.

In order to pulverize the thermoplastic elastomer composition while keeping it in a cooled state, it is preferable that the pulverization be carried out by a method having good pulverization efficiency and low heat generation. Crushing method is used. The powder of the thermoplastic elastomer composition in this method is usually sized to pass through a Tyler standard sieve 24 mesh (mesh size 700 μm × 700 μm), preferably 28 mesh (mesh size 590 μm ×
590 μm), more preferably 32 mesh (500 μm × 500 μm), particularly preferably 42 mesh (355 μm × 355 μm).
m).

Since the powder of the thermoplastic elastomer composition is not uniform in shape, the powder fluidity can be improved by coating the surface with a fine powder. As a fine powder, the primary particle size is 1
Fine powder having a size of 0 μm or less is used. As the fine powder, inorganic oxide, vinyl chloride resin for paste, fatty acid metal salt, calcium carbonate, powder pigment (however, when the pigment is contained in the thermoplastic elastomer composition, it is preferable that the pigment has the same color as the pigment. ) And the like. The primary particle size of the fine powder needs to be 10 μm or less, preferably 5 μm or less, and more preferably 5 nm to 5 μm. Here, the primary particle size means that a photograph of the fine powder is taken by a transmission electron microscope (TEM),
It is a value obtained by measuring the diameter of particles by selecting about 000 particles and dividing the diameter of these particles by the number of particles.

As the inorganic oxide, alumina, silica,
Examples include alumina silica and calcium carbonate. Alumina is a fine powder composed mostly of units of the chemical formula Al ₂ O ₃ . Alumina has various crystal forms, and any of the crystal forms can be used. These are called α-alumina, β-alumina, γ-alumina, etc. depending on the crystal form. Alumina C (γ-alumina) manufactured by Degussa, AKP-G008 (α-alumina) manufactured by Sumitomo Chemical Co., Ltd., and the like can be given.

Most of silica has the chemical formula SiO ₂
It is a fine powder composed of units. Crushing natural diatomaceous earth,
It is produced by a method such as decomposition of sodium silicate. OX50 manufactured by Degussa Corporation and the like can be mentioned. Alumina silica is an inorganic oxide containing the aforementioned alumina and silica as main components.

The surface of these inorganic oxides may be coated with dimethyl silicone oil or the like, or may be surface-treated with a trimethylsilyl group or the like.

Examples of powdered pigments include organic pigments such as azo, phthalocyanine, sulene and dye lakes, oxides such as titanium oxide, molybdic acid chromate, selenium sulfide compounds, ferrocyan compounds, carbon black and the like. Are used.

It is preferable that these fine powders are used alone or in combination of two or more having a primary particle size of 10 μm or less. For example, an inorganic oxide alone can be used, or a powdered pigment and an inorganic oxide can be used in combination. As fine powder, 1
With a secondary particle size of 300 nm or less;
m when used in combination, compared to when each is used alone, and the bulk specific gravity (packing properties)
In addition, a thermoplastic elastomer composition powder for powder molding having excellent agglomeration resistance can be obtained.

When a powder pigment is used, a pigment supported on a carrier such as calcium carbonate, metal soap, or magnesium oxide may be used. In this case, the primary particle size of the carrier is usually 10 μm or less, preferably 1 μm to 5 μm. In this case, the weight ratio between the powder pigment and the carrier is usually 2
0: 80-80: 20, preferably 25: 75-75:
25.

The amount of the fine powder is 0.1 to 10 parts by weight based on 100 parts by weight of the powder of the thermoplastic elastomer composition.
Parts by weight, preferably 0.2 to 8 parts by weight. If the added amount is less than 0.1 part by weight, the powder flow properties and powder moldability of the powder of the thermoplastic elastomer are inferior. 10
If the amount is more than 10 parts by weight, the thermal fusion between the powders of the thermoplastic elastomer is reduced, so that the strength of the obtained powder molded body tends to be poor.

The method of blending the fine powder with the powder of the thermoplastic elastomer composition is not particularly limited as long as the fine powder is uniformly adhered to the powder of the thermoplastic elastomer. For example, a method of blending using a blender with a jacket, a high-speed rotary mixer, or the like can be used. Among them, a method of uniformly dispersing the powder by applying a shearing force to prevent cohesion of the powders, such as a Henschel mixer or a super mixer, is preferred. The compounding is usually performed at room temperature.

The powder of the thermoplastic elastomer composition used for producing the powder molded product which is the outermost layer of the automobile interior part of the present invention can also be produced by the following method. In this case, a powder having excellent powder fluidity can be obtained without blending the aforementioned fine powder, but blending the fine powder can further improve the powder fluidity.

Solvent treatment method: The thermoplastic elastomer composition is cooled to its glass transition temperature or lower (usually -70 ° C or lower, preferably -90 ° C or lower) and pulverized. Then, the powder of the thermoplastic elastomer composition produced by the above-mentioned freeze pulverization method, in a solvent having poor compatibility with the thermoplastic elastomer composition, in the presence of a dispersant and an emulsifier,
After stirring at a temperature equal to or higher than the melting temperature of the thermoplastic elastomer composition, preferably 30 to 50 ° C. higher than the melting temperature, the composition is cooled (for example, see JP-A-62-280226). In the solvent treatment method, as the solvent, for example, ethylene glycol, polyethylene glycol,
Polypropylene glycol or the like is usually 300 to 1000 per 100 parts by weight of the thermoplastic elastomer composition.
It is used in an amount of preferably from 400 to 800 parts by weight. As the dispersant, for example, ethylene-acrylic acid copolymer, silicic anhydride, titanium oxide and the like are usually 5 to 2 per 100 parts by weight of the thermoplastic elastomer composition.
0 parts by weight, preferably in the range of 10 to 15 parts by weight. As the emulsifier, for example, polyoxyethylene sorbitan monolaurate, polyethylene glycol monolaurate, sorbitan tristearate and the like are usually 3 parts per 100 parts by weight of the thermoplastic elastomer composition.
It is used in an amount of from 15 to 15 parts by weight, preferably from 5 to 10 parts by weight.

Strand cutting method: A molten thermoplastic elastomer composition is extruded from a die into air to form a strand, which is cooled and cut (for example,
See JP-A-50-149747). In the above-mentioned strand cutting method, the discharge diameter of the die is usually in the range of 0.1 to 3 mm, preferably 0.2 to 2 mm. The discharge rate of the thermoplastic elastomer composition per discharge port of the die is usually in the range of 0.1 to 5 kg / hour, preferably 0.5 to 3 kg / hour. The take-off speed of the strand is usually 1 to 100 m / min, preferably 5 to 100 m / min.
It is in the range of 50 m / min. Moreover, the cooled strand is usually 1.4 mm or less, preferably 0.3 to 1.2.
mm.

Die face cutting method: The molten thermoplastic elastomer composition is cut while being extruded from a die into water. In the die face cutting method, the discharge diameter of the die is usually in the range of 0.1 to 3 mm, preferably 0.2 to 2 mm. The discharge rate of the thermoplastic elastomer composition per discharge port of the die is usually in the range of 0.1 to 5 kg / hour, preferably 0.5 to 3 kg / hour. The temperature of the water is usually in the range from 30 to 70C, preferably from 40 to 60C.

The powder of the thermoplastic elastomer composition can be applied to various powder molding methods such as a powder slush molding method, a fluid immersion method, an electrostatic coating method, a powder spraying method, and a powder rotational molding method. For example, the powder slush molding method is performed as follows.

First step: A step of applying a fluorine-based and / or silicon-based release agent on the molding surface of the mold. In the case of performing powder molding with the powder of the thermoplastic elastomer composition of the present invention, in the sixth step, When removing from the mold,
Since the adhesion to the inner surface of the mold may be strong, if the forcible removal is attempted, the obtained molded body may be broken.
Therefore, although not essential, it is preferable that the inner surface of the mold is previously coated with a spray of a silicone-based release agent or a fluorine-based release agent. As a silicone spray, for example, KF96SP (diluted organic solvent) manufactured by Shin-Etsu Silicone Co., Ltd., and as a fluorine-based spray, Daifree GA-6010 (diluted organic solvent) manufactured by Daikin, ME-
413 (water-diluted product).

Second step: a step of supplying the powder of the thermoplastic elastomer composition onto the molding surface of the mold heated to a melting temperature of the powder of the thermoplastic elastomer composition or more. Above the melting temperature of the composition, usually 160-320 ° C., preferably 2
It is supplied onto the molding surface of a mold heated to 10 to 300 ° C. In this method, the mold is heated by, for example, a gas heating furnace method, a heat medium oil circulation method, a dipping method in heat medium oil or hot fluidized sand, a high-frequency induction heating method, or the like. The heating time for heat-sealing the powder of the thermoplastic elastomer composition is appropriately selected according to the size and thickness of the target molded article.

Third step: a step of heating the powder of the thermoplastic elastomer composition on the molding surface of the second step for a predetermined time and fusing powders having at least their surfaces fused to each other on the molding surface. Is heated for a predetermined period of time, so that the powders whose surfaces have at least been fused are fused together.

Fourth step: a step of collecting the unfused powder after a lapse of the predetermined time in the third step. After the lapse of the predetermined time, the unfused powder is collected.

Fifth step: If necessary, a step of further heating the mold on which the powder of the molten thermoplastic elastomer composition is placed. If necessary, the powder of the molten thermoplastic elastomer composition is placed on the mold. The heating mold is further heated.

Sixth step: After the fifth step, the mold is cooled, and the molded body formed thereon is removed from the mold. The mold is cooled, and the molded body formed thereon is removed. Remove from mold. Further, during the production of the thermoplastic elastomer composition for powder molding, by internally adding the aforementioned lubricant,
This has the effect of reducing the load required when removing the compact in the sixth step. In this case, the first step described above can be omitted. The amount of the lubricant added is usually 5 parts by weight or less, preferably 0.1 to 2 parts by weight, per 100 parts by weight of the thermoplastic elastomer composition. If the amount of the lubricant exceeds 5 parts by weight, problems such as reduction in the strength of the obtained molded article and contamination of the mold surface may occur.

Although the powder compact as the outermost layer of the automobile interior part of the present invention is used as a skin material, a two-layer compact having a foamed layer laminated inside may be used as the skin material. Such a two-layer molded body is obtained by a powder molding method (Japanese Patent Laid-Open No.
No. 73, etc.), or it can be manufactured by a method of bonding a separately manufactured foam to the molded article obtained above with an adhesive or the like.

In order to produce a two-layer compact by a powder molding method, a two-layer powder slush molding method (see Japanese Patent Application Laid-Open No. 5-473, etc.) is preferably used. In the two-layer powder slush molding method, after heating a mold, which may have a complicated pattern on the molding surface thereof, to a melting temperature of the powder of the thermoplastic elastomer composition or more, the above-mentioned molding is performed on the molding surface of the mold. The powder of the thermoplastic elastomer composition is supplied, and the powders are thermally fused to each other to obtain a sheet-like molten material on the molding surface, and then the excess powder not thermally fused is removed. Powder of a thermoplastic elastomer composition containing a foaming agent on a powdery melt (whether a fine powder is compounded or not) can be used. After the powder is thermally fused to each other to obtain a sheet-like melt on the molding surface, excess powder that has not been thermally fused is removed, and then further heated to foam the foamed layer. If you let it form There.

Further, it is also possible to obtain a composite molded article composed of a non-foamed layer, a foamed layer and a non-foamed layer by a powder molding method. In this case, the non-foamed layers may be the same or different.

The powder of the thermoplastic elastomer composition containing a foaming agent can be prepared by previously incorporating the powder into the powder of the thermoplastic elastomer composition, or by using a rotary mixer such as the aforementioned Henschel mixer. Can be manufactured by a method of coating on the surface of powder.

The foaming agent can be added simultaneously with the fine powder described above. As the foaming agent, a pyrolytic foaming agent is usually used. Examples of such a pyrolytic foaming agent include azo compounds such as azodicarbonamide, 2,2'-azobisisobutyronitrile, and diazodiaminobenzene, benzenesulfonyl hydrazide, benzene-1,3-sulfonyl hydrazide, p- Sulfonyl hydrazide compounds such as toluenesulfonyl hydrazide, N, N'-dinitrosopentamethylenetetramine, N, N'-dinitroso-
Examples include nitroso compounds such as N, N'-dimethylterephthalamide, azide compounds such as terephthalazide, and carbonates such as sodium bicarbonate, ammonium bicarbonate and ammonium carbonate. Among them, azodicarbonamide is preferably used. The compounding of the blowing agent is usually performed at a temperature equal to or lower than the decomposition temperature of the blowing agent. Further, the powder of the thermoplastic elastomer composition may contain a foaming aid and a cell conditioner together with the foaming agent.

Instead of the powder of the thermoplastic elastomer composition containing a foaming agent, a thermoplastic polymer composition such as a vinyl chloride resin, a polyolefin resin, or an olefin thermoplastic elastomer other than those described in the present invention is used. It can also be used. Further, as the thermoplastic polymer composition containing a foaming agent, a polyethylene foamable composition used in JP-A-7-228720 can be used. The fine powder described above may be blended with the powder of these thermoplastic polymer compositions.

Further, a polyurethane foam can be used as the foam layer. In this case, since the thermoplastic elastomer composition constituting the powder molded body, which is the outermost layer of the automotive interior material of the present invention, tends to be inferior in adhesion to the polyurethane foam, it is usually molded with a primer such as chlorinated polyethylene. By pre-treating the adhesive surface of the body, the adhesiveness can be improved. The polyurethane foam is obtained by fixing the above-mentioned molded body and a core material to be described later in a predetermined gap with a predetermined gap, injecting a mixture of polyol and polyisocyanate into the gap, and foaming under pressure. Formed by

Such a molded article or a two-layer molded article is suitable as a skin material laminated on a thermoplastic resin core material. For example, the molded article is a multi-layered product in which a thermoplastic resin core material is laminated on one surface side. It can be used as a molded article, and the two-layer molded article can be used as a skin material of a multilayer molded article in which a thermoplastic resin core is laminated on the foam layer side.

As the thermoplastic resin in the thermoplastic resin core material, for example, a polyolefin such as polypropylene or polyethylene, or a thermoplastic resin such as an ABS (acrylonitrile-butadiene-styrene copolymer) resin is used. Among them, a polyolefin such as polypropylene is preferably used. Such a multi-layer molded article is supplied, for example, by supplying a thermoplastic resin melt to one surface side of the molded article and applying a pressure or by supplying a thermoplastic resin melt to the foam layer side of the two-layer molded article and applying a pressure. It can be easily manufactured.

A thermoplastic resin melt is a thermoplastic resin that is heated to a temperature higher than its melting temperature and is in a molten state. The supply of the thermoplastic resin melt may be before the pressurization or may be simultaneous with the pressurization. The pressurization may be performed by using a mold or the like, or may be performed by the supply pressure of the thermoplastic resin melt. Examples of such a molding method include an injection molding method, a low-pressure injection molding method, and a low-pressure compression molding method.

Specifically, the above-mentioned powder compact is supplied between a pair of opened molds, and then heat is applied between one surface of the compact and one mold facing the same. It is only necessary to clamp both molds after or while supplying the plastic resin melt, and when using a two-layer powder molded body as the skin material, the two-layer molded body is placed between a pair of opened molds. The molds may be clamped after or after the thermoplastic resin melt is supplied between the foamed layer of the molded article and one of the molds opposed thereto. Here, the opening / closing direction of the two dies is not particularly limited, and may be a vertical direction or a horizontal direction.

Further, the powder molding die can be used as one of the dies in the production of the multilayer molded product while holding the molded product or the two-layer molded product on the molding surface.
According to this method, the molded article or the two-layer molded article on which the pattern of the mold is transferred is supplied between the molds without being separated from the mold, so that the pattern imprinted on the surface is almost broken. Thus, a desired multilayer molded body can be obtained.

The thermoplastic resin melt may be supplied after the clamping of both the molds is completed. However, a multilayer molded article in which the molded article or the two-layer molded article as the skin material has a small displacement and the degree of pattern transfer is improved. It is preferable that both dies be clamped during or after supply while both dies are not closed.
The method of supplying the thermoplastic resin melt is not particularly limited. For example, the thermoplastic resin melt can be supplied from a resin passage provided in one of the molds facing the molded product or the two-layer molded product.
Alternatively, the supply nose of the molten resin may be inserted between the two dies to supply the molten resin, and thereafter, the supply nose may be retracted outside the system to close both the dies. As the pair of dies, a pair of male and female dies in which the outer peripheral surface of one die and the inner peripheral surface of the other die can slide can be used. In this case, by keeping the clearance between the sliding surfaces of the two dies approximately equal to the thickness of the molded article or the two-layer molded article, a multilayer molded article having an extra skin material at its end can be obtained. By folding this extra skin material on the back surface of the multilayer molded body, a multilayer molded body whose end is covered with the skin material layer can be obtained.

The automobile interior part of the present invention is an automobile interior part having the above-mentioned powder compact in the outermost layer and having an airbag incorporated therein, and may be used in an instrument panel, a handle, a curtain airbag part, a door part and the like. Can be used.

The automobile interior part of the present invention is an automobile interior part having the above-mentioned powder compact in the outermost layer and having an airbag incorporated therein, but is designed so that the deployed portion of the airbag cannot be distinguished from the outside. The airbag may be of an integrated type or may be designed so that the deployed portion of the airbag can be determined from the outside.

An integrated automobile interior part designed so that the deployment portion of the airbag cannot be distinguished from the outside is also excellent in design.

The airbag deployment portion of such an automobile interior part cannot be discriminated from the outside by using a laser beam or the like from the inside of the outermost layer of the powder molded body made of the thermoplastic elastomer composition (powder molding). It is formed by forming a cleavage line (seam) (not to be cut by a certain thickness from the outside of the body) into an H-shape or U-shape to weaken the deployment site. At this time, the outermost layer of the powder compact is usually controlled so that about 0.3 to 0.7 mm is not cut.

Further, a cleavage line can be formed simultaneously with the foamed layer and / or the thermoplastic resin core material already integrated with the powder molding layer.

[0091] Such an automobile interior part can be manufactured by a method such as installing an airbag module after forming a cleavage line by the above-described method.

Further, a molded body in which the foam layer and / or the thermoplastic resin core material is not bonded only to the portion where the airbag is built in is manufactured in advance, and a cleavage line is formed at the airbag deployment site by the above-described method. At least, it can be manufactured by installing an airbag module.

A method for manufacturing an integrated automobile interior part designed such that the deployed portion of the airbag cannot be distinguished from the outside is described in JP-A-2000-238595, JP-A-10-119690 and the like. ing.

Further, a concave portion which is recessed from the back side to the front side is formed in the mold body at a position corresponding to the deployment portion of the airbag.
After forming the outermost layer powder molding layer using a powder molding die formed thinner than the mold thickness of the peripheral portion,
A method of manufacturing an automobile interior part by incorporating an airbag is described in Japanese Patent Application Laid-Open No. H10-119962.

As a method of manufacturing an automobile interior part designed so that the deployed portion of the airbag can be distinguished from the outside, a method of manufacturing a part on the surface side (the side to which powder is supplied) corresponding to the deployed portion of the airbag can be used. However, there is a method of forming the outermost powder molding layer using a powder molding die formed to be thicker than the mold thickness of the peripheral portion, and then incorporating the airbag by the above-described method.

Further, an airbag cover material manufactured in advance by a method such as injection molding using the thermoplastic elastomer composition of the present invention or the like is manufactured by a method according to the present invention in which parts other than the airbag cover material are manufactured. The automobile interior part of the present invention can also be manufactured by separately combining with the formed body.

Further, by coating the surface of the powder molded body, which is the outermost layer of the automobile interior part of the present invention, with a paint, it is possible to improve the scratch resistance and wear resistance of the molded body. Known paints such as urethane paints and acrylic paints can be used as the paint.

[0098]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. The following methods were used to evaluate the thermoplastic elastomer composition and the molded article. [1] Complex dynamic viscosity η ^* (1) and Newton viscosity index n Dynamic analyzer (RD) manufactured by Rheometrics
S-7700), the storage elastic modulus G ′ (ω) and the loss elastic modulus G ″ (ω) were measured at the vibration frequency ω = 1 radian / sec or 100 radian / sec, and the above equation (2) was used. ) Was used to calculate the complex dynamic viscosity η ^* (1) and η ^* (100). The measurement was performed in a parallel plate mode, an applied strain of 5%, and a sample temperature of 250 ° C. Also, η ^* (1) and η
^{* Using} (100), the Newtonian viscosity index n was determined by the above-mentioned equation (3). Note that the polyvinyl chloride resin used in Comparative Example 2 was not measured because the deterioration progressed during the measurement under the above conditions. [2] (II) Total vinyl aromatic compound unit content in the hydrogenated diene copolymer was determined by ¹ H-NMR measurement (frequency: 90 MHz) using a carbon tetrachloride solution of (II). [3] (II) Ratio of the number of hydrogenated conjugated diene units having side chains having 2 or more carbon atoms to the number of all hydrogenated conjugated diene units in the hydrogenated diene-based copolymer (V) red Was determined by the Morero method using external analysis. [4] Ratio of (A) vinyl aromatic compound content in vinyl aromatic compound polymer block to total vinyl aromatic compound content in hydrogenated diene copolymer in (II) tetrachloride of (II) It was determined by ¹ H-NMR measurement (frequency: 90 MHz) using a carbon solution. [5] The degree of hydrogenation of the double bond of the conjugated diene unit in the hydrogenated diene copolymer was determined by ¹ H-NMR measurement (frequency: 90 MHz) using a carbon tetrachloride solution of (II). [6] Gel permeation chromatography (GP) at 38 ° C. using a tetrahydrofuran solution having a number average molecular weight (II) of hydrogenated diene copolymer
It was determined as a polystyrene equivalent value by the method C). [7] Bending whitening property of powder slush molded product obtained by powder slush molding of powder of thermoplastic elastomer composition A molded product having a thickness of 1 mm obtained by the powder slush molding method described below is cut into 1 cm x 5 cm. , Bending load 1
One minute after bending with kg, the load was removed, and the following criteria were used to evaluate the width of the whitened portion by bending. 1: A whitened portion was observed. 2: No whitened portion was observed. [8] Cold resistance of powder slush molded product Using a 1 mm thick powder slush molded product obtained by the powder slush molding method described below, a tensile test at −30 ° C. was performed using a tensile tester (manufactured by Instron Corporation; (Model 5565 tensile tester). The tensile speed was 200 mm / min, and a test piece was obtained by punching the powder slush compact with a JIS No. 3 dumbbell. [9] Change in appearance when powder slush compact is heated A 1 mm thick powder slush compact obtained by the powder slush molding method described below is controlled in a gear oven (perfect oven, manufactured by Tabai Co., Ltd., model number: 110 ° C.). PH-200) for 100 hours, and a gloss value before and after heating was measured with a digital goniophotometer (manufactured by Suga Test Instruments Co., Ltd., model number UGV-5DI, reflection angle 60 °), and the gloss value before and after heating was measured. It was determined based on the difference. 1: The difference in gloss value was larger than 0.6. 2: The difference in gloss value was in the range of more than 0.3 and 0.6 or less. 3: The difference in gloss value was 0.3 or less.

Example 1 [Production of thermoplastic elastomer composition powder] Propylene-ethylene copolymer resin [manufactured by Sumitomo Chemical Co., Ltd., ethylene unit content 5% by weight, MFR = 228 g /
10 minutes] 100 parts by weight and a hydrogenated product of a styrene-butadiene-styrene copolymer (corresponding to the structure of (A)-(B3)-(A)) [total styrene unit content: 15% by weight, total styrene unit content: (A) Part of vinyl aromatic compound unit content to 100%, MFR = 30 g / 10 min, hydrogenated conjugated diene unit having a side chain having 2 or more carbon atoms based on hydrogenated total conjugated diene unit The proportion is 80%, the hydrogenation rate is 98%, the number average molecular weight is 130,000] 122 parts by weight, an ethylene-propylene copolymer rubber [Supreto Chemical Industries, Ltd., Esprene V0141, propylene unit content 27]
% By weight, MFR = 0.7 g / 10 min], and 49 parts by weight and 2.6 parts by weight of a brown pigment are kneaded at a temperature of 170 using a biaxial kneader [TEX-44, manufactured by Nippon Steel Corporation]. Composition [η * (1) = 1.2 × 10 ³ poise, n = 0.04]
Was obtained using a cutting machine to obtain pellets.
After cooling the pellets at −120 ° C. using liquid nitrogen,
The powder was pulverized while being kept in a cooled state to obtain a powder of a thermoplastic elastomer composition [passing through a 42-mesh Tyler standard sieve (opening: 355 μm × 355 μm)].

[Production of Molded Product by Powder Slush Molding Method] A powder of the obtained thermoplastic elastomer composition was heated at 280 ° C. with a mold having a grain pattern (30 cm).
Corner) and then left for 15 seconds,
Excess powder was washed off and stored in an oven at 280 ° C. for 1 minute. Thereafter, the mold on which the powder of the thermoplastic elastomer composition melted in a sheet shape was water-cooled,
A sheet having a thickness of 1 mm was obtained by removing the sheet from the mold. The above-mentioned evaluation was performed using this powder slush powder compact. The evaluation results are shown in Tables 1 and 2.

Comparative Example 1 Instead of the styrene-butadiene-styrene copolymer used in Example 1, styrene-butadiene-styrene-
Hydrogenated styrene copolymer ((A)-(B1)-(A)
Corresponding to the structure, the total styrene unit content is 9% by weight, the vinyl aromatic compound unit content of part (A) is 48% based on the total styrene unit content, the MFR is 10 g / 10 min, and the total hydrogenated conjugated diene unit is The ratio of the hydrogenated conjugated diene unit having a side chain having 2 or more carbon atoms is 80%, and the hydrogenation rate is 98%.
%, Number-average molecular weight 200,000) was used for the evaluation according to Example 1. The evaluation results are shown in Tables 1 and 2.

Comparative Example 2 Evaluation was made in the same manner as in Example 1 except that the powder of the thermoplastic elastomer composition used in Example 1 was replaced with a powder of a polyvinyl chloride resin produced by the following method. Was done. Table 2 shows the evaluation results.

[Production Method of Polyvinyl Chloride Resin] 90 parts by weight of granular polyvinyl chloride resin (ZEST-800Z, degree of polymerization 800, manufactured by Shin-Daiichi PVC Co., Ltd.) is put into a high-speed mixer, and the rotation speed is constant. Heat with stirring at 8
When the temperature reaches 0 ° C., trimellitate plasticizer 6
0 parts by weight, 3 parts by weight of a barium-zinc-based stabilizer and 1 part by weight of a black pigment were added, and the mixture was heated with stirring to perform dry blending. Thereafter, when the temperature reached 120 ° C., cooling was started, and when the temperature reached 50 ° C., 10 parts by weight of a fine vinyl chloride resin (ZEST-QLT, manufactured by Shin-Daiichi PVC Co., Ltd.) was added and stirred. Disperse evenly,
A powder of a vinyl chloride resin was obtained. The average particle size of the obtained powder was 150 μm.

[0104]

[Table 1] Hydrogenated diene copolymer

[0105]

[Table 2] Physical properties of powder slush compacts * 1 The polyvinyl chloride resin used in Comparative Example 2 was not measured because the deterioration progressed during the measurement under the conditions described above.

[0106]

As described above, according to the present invention, a thermoplastic elastomer composition containing a polyolefin-based resin and a specific hydrogenated diene-based copolymer as essential components has excellent flexibility, and when folded. An airbag with excellent cold shock resistance is built in. The outermost layer has a powder molded body that does not emit gloss when heated at a temperature of about 80 ° C to less than the melting point of the polyolefin resin. Car interior parts were obtained.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) C08L 23/08 C08L 23/08 4J026 53/02 53/02 // B60K 37/00 B60K 37/00 A BJ B29K 23 : 00 B29K 23:00 25:00 25:00 105: 04 105: 04 B29L 31:58 B29L 31:58 F term (reference) 3D044 BA07 BB01 BC04 BC15 3D054 AA13 AA14 BB01 BB08 FF02 FF03 4F071 AA12 AA12X AA15 AA21 AA21 AA22X AA75 AH11 BA01 BB01 BB13 BC01 BC07 4F205 AA03 AA12 AA45 AA47F AC04 AD17 AG03 AG20 AH18 AH19 AH25 AH26 GA13 GB01 GB11 GC04 GE03 GE24 GF01 GF05 GN13 4J002 BB03W BB12W05 BB14W01 BB14W01 BB14W01

Claims (9)

[Claims] 1. The following (I) 100 parts by weight and (II) 10
An automobile interior part with a built-in airbag, having an outermost layer of a powder molded body comprising a thermoplastic elastomer composition containing up to 1000 parts by weight. (I): Polyolefin resin (II): Hydrogenated diene copolymer satisfying all of the following conditions: Hydrogenated diene copolymer contains the following structural units (A) and (B) (A): Polymer block of vinyl aromatic compound (B): At least one type of block selected from the following (B1), (B2) and (B3) (B1): Random copolymer of vinyl aromatic compound and conjugated diene A block obtained by hydrogenating a polymer block (B2): a block comprising a vinyl aromatic compound and a conjugated diene, and a block obtained by hydrogenating a tapered block in which a vinyl aromatic compound is gradually increased (B3): a conjugated diene polymer Block obtained by hydrogenating a block: Total vinyl aromatic compound unit content (T) contained in the hydrogenated diene copolymer is 10 to 18% by weight: Hydrogenated diene copolymer The ratio (S: percentage) of the vinyl aromatic compound unit content of the above (A) to the total vinyl aromatic compound unit content in the body is 3% or more: water in the hydrogenated diene copolymer The ratio (V: percentage) of the number of hydrogenated conjugated diene units having a side chain having 2 or more carbon atoms to the total number of added conjugated diene units exceeds 60%. The relationship between (T), (S) and (V) above satisfies the following formula (1): V ≦ 0.375 × S + 1.25 × T + 40 (1): hydrogenated diene copolymer 80% or more of the double bonds of the conjugated diene unit in the union are hydrogenated: the number average molecular weight of the hydrogenated diene copolymer is 50,000 to 60
Be a million 2. The method of claim 2, wherein (II) is represented by the general formula [(A)-(B1)]
n- (A), [(A)-(B2)] n- (A),
[(A)-(B3)] n- (A), [(A)-(B
1)] n, [(A)-(B2)] n or [(A)-(B
3)] a hydrogenated diene system represented by n (where n is an integer of 1 or more and repeating units (A), (B1), (B2) and (B3) may be the same or different) The automobile interior part according to claim 1, which is a copolymer. 3. The automotive interior part according to claim 1, wherein in (II), the conjugated diene is butadiene and the vinyl aromatic compound is styrene. 4. The thermoplastic elastomer composition according to claim 1, wherein
The automotive interior part according to claim 1, wherein the component (III) contains 250 parts by weight or less per 100 parts by weight. (III): ethylene-α-olefin copolymer 5. The automotive interior part according to claim 1, wherein the powder compact is a powder slush compact. 6. The automobile interior part according to claim 1, wherein a foamed layer is lined inside the powder compact. 7. The automobile interior part according to claim 1, wherein the automobile interior part is an instrument panel, a handle, a curtain airbag part or a door part. 8. The automobile interior part according to claim 1, wherein the airbag deployment part is designed to be indistinguishable from the outside. 9. The vehicle interior part according to claim 1, wherein the airbag deployment part is designed to be able to be determined from the outside.