JP5007292B2 - Resin composition for seamless automotive interior parts and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition for seamless automobile interior parts capable of expanding certainly when an air-bag is actuated, the resin composition enabling installment of an air-bag system seamlessly, owing to excellent rigidity, impact resistance, and appearance, as well as to excellent vibration welding property with an air-bag kit. <P>SOLUTION: The resin composition includes (A) a propylene-ethylene block copolymer consisting of 50-85 wt.% of a crystalline polypropylene component having a melt flow rate of 50-130 g/10 min (230&deg;C, 21.18 N load) and 15-50 wt.% of a propylene-ethylene random copolymer component; (B) a propylene-ethylene block copolymer consisting of 70-95 wt.% of a crystalline polypropylene component having a melt flow rate of 5-45 g/10 min and 5-30 wt.% of a propylene-ethylene random copolymer component; (C) a copolymer rubber of ethylene having a melt flow rate of 0.5-10 g/10 min and a 3-6C &alpha;-olefin; (D) a copolymer rubber of ethylene having a melt flow rate of 0.5-10 g/10 min and a 7-18C &alpha;-olefin; and (E) an inorganic filler. The content ratio for each components of the resin composition is 10-50 wt.% for (A), 25-55 wt.% for (B), 5-15 wt.% for (C), 3-10 wt.% for (D), and 5-20 wt.% for (E) (wherein the total amount of (A)-(E) is 100 wt.%). <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a resin composition for seamless automobile interior parts and a seamless automobile interior part obtained therefrom, and more specifically, since it has excellent rigidity, impact resistance, appearance, and vibration welding characteristics with an air bag kit. The present invention relates to a resin composition for seamless automobile interior parts that can be seamlessly provided with a bag system and can be reliably deployed when an airbag is operated, and a seamless automobile interior part obtained therefrom.

Conventionally, automobile airbag devices are automobile interior parts that require rigidity (instrument panels, roof linings, side pillars, etc.) and airbag covers that require excellent deployability in a wide temperature range from low to high temperatures. Because of the different materials, both were molded separately and incorporated into automotive interior parts (instrument panels, roof linings, side pillars, etc.).
For this reason, there is a seam at the boundary between the airbag cover portion and the automobile interior part such as an instrument panel.
However, in recent years, seamless automotive interior parts, such as seamless instrument panels, where the seam is not visible from automotive interior parts, such as instrument panels, for safety reasons such as avoiding reflection on the design surface and windshield. There was a request for the transition to.
One solution is a method of covering with a skin material (Patent Document 1), but there is a problem that the manufacturing process is complicated and expensive.

  On the other hand, the connection between automobile interior parts such as instrument panels and airbag kits is widely done with screws, hooks, etc., but various parts are required and there is a problem that leads to an increase in weight. Therefore, it has been proposed to fix by welding.

Under such circumstances, a method for integrally molding the instrument panel and the airbag cover with the same material has been proposed, and various resin compositions used therefor have been developed (for example, Patent Documents 2, 3, 4, 5). ).
For example, Patent Document 2 discloses that ethylene-propylene (··) having a flexural initial elastic modulus of 500 to 1000 MPa and an Izod impact test at −40 ° C. of 40 to 70 parts by weight of a polypropylene resin and a Mooney viscosity of 20 to 70 is obtained. 5-30 parts by weight of non-conjugated diene) copolymer rubber, 5-30 parts by weight of ethylene / propylene (non-conjugated diene) copolymer rubber having Mooney viscosity of 90-180, and 1 to 50 g / 10 min of MFR A thermoplastic resin composition for an instrument panel in which an airbag cover made up of 5 to 30 parts by weight of an octene copolymer and 1 to 15 parts by weight of talc is integrated is disclosed.

  Patent Document 3 includes 50 to 95% by mass of polypropylene, 0 to 20% by mass of thermoplastic elastomer, and 5 to 30% by mass of talc. Among the talc, talc having an average particle size exceeding 10 μm is based on the composition. The resin composition for a seamless airbag cover is disclosed as 5% by mass or more.

Patent Document 4 contains the following components (A) to (C), and the total of the homo component, the copolymer component and the component (C) is 100% by weight, and the content of the homo component is 40 to 50. An air bag cover-integrated resin composition for an instrument panel is disclosed in which the content of the copolymer component is 30 to 40% by weight and the content of the component (C) is 10 to 30% by weight. Yes.
(A): Propylene-based resin composed of block polypropylene (a1) and homopolypropylene (a2) (B): Density is less than 870 kg / m ³ , 5 g of melt rate measured under conditions of temperature 190 ° C. and 21.18 N / 10 min or less ethylene-α-olefin copolymer (C): Talc (however, the homo component is a combination of the homo part of (a1) and (a2), and the copolymer component is (a1) The copolymer part of (B) and (B) are combined.)

  Patent Document 5 includes 50 to 90% by mass of polypropylene, 0 to 20% by mass of thermoplastic elastomer and 10 to 30% by mass of talc, and the talc has an average particle size of 15 to 25 μm and a particle size of 5 μm or less. A resin composition for a seamless airbag cover or a resin composition for a seamless instrument panel with an airbag cover having a particle size distribution of 10% by mass or less and those having a particle size of 40 μm or less are disclosed.

However, since the conventional resin composition for an instrument panel as described above has both rigidity as an instrument panel and deployability as an air bag cover, the welded portion is still peeled when fixed by welding. There was a problem that. That is, in a seamless instrument panel using a conventional resin composition for an instrument panel, even if the airbag kit is fixed by vibration welding, the vibration welding strength is low, and the instrument panel and the airbag kit are operated when the airbag is activated. Separation occurred at the welded part, and the airbag cover part could not be deployed.
In addition, there is a problem that the instrument panel itself is destroyed at a portion other than the planned deployment line due to an impact at the time of air bag operation.

  Therefore, it eliminates the problems of conventional resin compositions for automotive interior parts (instrument panels, etc.), and for new seamless automotive interior parts (seamless instrument panels, etc.) that can be seamlessly equipped with an airbag system. Research and development of resin compositions has been demanded.

JP 2007-176991 A Japanese Patent Laid-Open No. 2003-183459 JP 2004-315640 A JP 2006-257259 A WO 2006/040825

  An object of the present invention is to provide a seamless, air bag system that can be seamlessly equipped with an air bag system because it has excellent rigidity, impact resistance, appearance, and vibration welding characteristics with an air bag kit. Providing resin compositions for automotive interior parts (seamless instrument panels, seamless roof lining, seamless side pillars, etc.) and seamless automotive interior parts (seamless instrument panels, seamless roof lining, seamless side pillars, etc.) obtained therefrom There is.

  As a result of intensive studies in order to solve the above problems, the present inventors have found that a propylene / ethylene block copolymer (A), a propylene / ethylene block copolymer (B), ethylene and 3 to 6 carbon atoms. In a resin composition comprising a copolymer rubber (C) with α-olefin, a copolymer rubber (D) with ethylene and an α-olefin having 7 to 18 carbon atoms, and an inorganic filler (E), By simultaneously identifying and optimizing the content of each component, seamless automotive interior parts (seamless instrument panel, seamless roof) with excellent rigidity, impact resistance and appearance, and greatly improved vibration weld strength The present inventors have found that a resin composition for lining, seamless side pillar, etc.) can be obtained, and completed the present invention.

  That is, according to the first invention of the present invention, a 50 to 85% by weight of a crystalline polypropylene component having a melt flow rate (230 ° C., load 21.18 N) of 50 to 130 g / 10 min and a propylene / ethylene random copolymer. Propylene / ethylene block copolymer (A) comprising 15 to 50% by weight of component, 70 to 95% by weight of crystalline polypropylene component having a melt flow rate (230 ° C., load of 21.18 N) of 5 to 45 g / 10 minutes, A propylene / ethylene block copolymer (B) comprising 5 to 30% by weight of a propylene / ethylene random copolymer component, ethylene having a melt flow rate (230 ° C., load 21.18 N) of 0.5 to 10 g / 10 min. And C3-C6 α-olefin copolymer rubber (C), melt flow rate (230 ° C., load 21.18 N) Consists of a copolymer rubber (D) of 0.5 to 10 g / 10 min of ethylene and an α-olefin having 7 to 18 carbon atoms and an inorganic filler (E), and the content of each component is ( A) is 10 to 50% by weight, (B) is 25 to 55% by weight, (C) is 5 to 15% by weight, (D) is 3 to 10% by weight, and (E) is 5 to 20% by weight (however, The total amount of (A) to (E) is 100% by weight.) A resin composition for seamless automobile interior parts is provided.

  According to the second invention of the present invention, in the first invention, the vibration welding strength (maximum point load) when the seamless automobile interior part and the airbag kit are fixed by vibration welding is 46 N or more. A resin composition for seamless automotive interior parts is provided.

  Furthermore, according to the third invention of the present invention, in the first or second invention, the melt flow rate (230 ° C., load 21.18 N) is 6 to 20 g / 10 min. A resin composition for interior parts is provided.

  According to a fourth aspect of the present invention, there is provided the resin composition for seamless automotive interior parts according to any one of the first to third aspects, wherein the seamless automotive interior part is a seamless instrument panel. Provided.

  According to the fifth aspect of the present invention, there is provided a seamless automobile interior part formed by molding the resin composition of any one of the first to third aspects.

  Moreover, according to the 6th invention of this invention, the seamless instrument panel formed by shape | molding the resin composition of the 4th invention is provided.

  According to the present invention, a propylene / ethylene block copolymer (A), a propylene / ethylene block copolymer (B), a copolymer rubber (C) of ethylene and an α-olefin having 3 to 6 carbon atoms, ethylene, In a resin composition comprising a copolymer rubber (D) and an α-olefin having 7 to 18 carbon atoms and an inorganic filler (E), by specifying each component and optimizing its content, Dispersibility of each component is remarkably improved, resulting in seamless automotive interior parts (seamless instrument panel, seamless roof lining, seamless side) with excellent rigidity, impact resistance and appearance, and greatly improved vibration weld strength It is presumed that a resin composition for pillars etc.) was obtained. The resin composition of the present invention is useful for seamless automotive interior parts (seamless instrument panels, seamless roof linings, seamless side pillars, etc.), especially for seamless instrument panels, and is very useful in industry. high.

  The present invention relates to 50 to 85% by weight of a crystalline polypropylene component having a melt flow rate (hereinafter referred to as MFR) (230 ° C., load 21.18 N) of 50 to 130 g / 10 min and a propylene / ethylene random copolymer component. 10 to 50% by weight of a propylene / ethylene block copolymer (A) (hereinafter also simply referred to as (A)) consisting of 15 to 50% by weight, and MFR (230 ° C., load 21.18N) of 5 to 45 g / Propylene / ethylene block copolymer (B) (hereinafter, also simply referred to as (B)) consisting of 70 to 95% by weight of 10 minutes crystalline polypropylene component and 5 to 30% by weight of propylene / ethylene random copolymer component Co-combination of ethylene and α-olefin having 3 to 6 carbon atoms of 25 to 55% by weight, MFR (230 ° C., load 21.18 N) of 0.5 to 10 g / 10 min Combined rubber (C) (hereinafter also referred to simply as (C)) is 5 to 15% by weight, MFR (230 ° C., load 21.18 N) is 0.5 to 10 g / 10 min of ethylene and 7 to 18 carbon atoms. Copolymer rubber (D) with α-olefin (D) (hereinafter also simply referred to as (D)) is 3 to 10% by weight, and inorganic filler (E) (hereinafter also simply referred to as (E)) is 5 to 20%. It is a resin composition for seamless automobile interior parts, characterized in that it contains wt% (however, the total amount of (A) to (E) is 100 wt%). Hereafter, the component which comprises the resin composition for seamless vehicle interior components of this invention, its manufacturing method, etc. are demonstrated in detail.

1. Propylene / ethylene block copolymer (A)
The propylene / ethylene block copolymer (A) used in the present invention can be obtained by a polymerization method including a propylene polymerization step and a propylene / ethylene random copolymerization step, a crystalline polypropylene component (A-1) and propylene / ethylene. It is a block copolymer containing a random copolymer component (A-2).

(1) Crystalline polypropylene component (A-1)
The crystalline polypropylene component (A-1) is preferably a homopolymer of crystalline propylene, but crystals obtained by copolymerizing a small amount of other comonomer with propylene within a range not significantly impairing the crystallinity. Copolymer may be used. The crystallinity of the component (A-1) is usually 90% or more, preferably 95 to 100% as an isotactic index (insoluble matter by boiling n-heptane extraction). When the crystallinity is small, the rigidity of the resin composition for seamless automobile interior parts is lowered.

Examples of the comonomer include α-olefins other than propylene such as ethylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene and 4-methyl-1-pentene, styrene, vinylcyclopentene and vinylcyclohexane. And vinyl compounds such as vinyl norbornane. Two or more of these may be copolymerized.
The amount of the comonomer when copolymerizing the comonomer with propylene is about 3% by weight or less based on the total weight of the component (A-1). Here, the comonomer content is a value determined by infrared spectroscopy (IR).

The MFR (230 ° C., load 21.18 N) of the crystalline polypropylene component (A-1) is 50 to 130 g / 10 minutes, preferably 55 to 125 g / 10 minutes, more preferably 55 to 120 g / 10. Minutes, more preferably 55 to 115 g / 10 minutes, and particularly preferably 60 to 100 g / 10 minutes. When the MFR (230 ° C., load 21.18 N) of the component (A-1) is less than 50 g / 10 minutes, or exceeds 130 g / 10 minutes, the vibration welding strength of the resin composition for seamless automotive interior parts is reduced, There is a poor deployment of the airbag.
In the present invention, it is necessary that the MFR of the component (A-1) be in the above range, whereby the resin composition for a seamless automotive interior part according to the present invention is a seamless automotive interior part having excellent vibration welding strength. You can get things.
In the present invention, MFR is measured at a temperature of 230 ° C. and a load of 21.18 N in accordance with JIS-K7210.

(2) Propylene / ethylene random copolymer component (A-2)
The propylene / ethylene random copolymer component (A-2) is a rubbery component obtained by random copolymerization of propylene and ethylene. (A-2) includes linear α-olefins such as butene-1, pentene-1, and hexene-1, branched α-olefins such as 3-methyl-1-butene and 4-methyl-1-pentene. Structural units derived from other monomers such as may be contained.

The ethylene content of the propylene / ethylene random copolymer component (A-2) is preferably 20 to 70% by weight, more preferably 25 to 50% by weight, and particularly preferably 30 to 45% by weight. Within this range, the impact properties of the resin composition for seamless automotive interior parts will be good.
Here, the ethylene content in the propylene / ethylene random copolymer component (A-2) is a value measured by a method described later.
The intrinsic viscosity [η] of the propylene / ethylene random copolymer component (A-2) is preferably 2.5 to 7.0 dl / g, more preferably 3.0 to 6.5 dl / g. If [η] is less than 2.5 dl / g, a flow mark may be generated on the interior parts of the seamless automobile and the appearance may be inferior. If it exceeds 7.0 dl / g, the unmelted material at the time of molding becomes lumpy. This may impair the appearance of seamless automobile interior parts.
Here, [η] in the propylene / ethylene random copolymer component (B-2) is measured in tetralin at 135 ° C. of the component (fraction 1) eluted at 40 ° C. or less in the temperature rising elution fractionation described later. Value.

(3) Physical properties of propylene / ethylene block copolymer (A) In the propylene / ethylene block copolymer (A) used in the resin composition for seamless automotive interior parts of the present invention, the crystalline polypropylene component (A-1) and The proportion of the propylene / ethylene random copolymer component (A-2) is 50 to 85% by weight of the crystalline polypropylene component (A-1), preferably 60 to 80% by weight, more preferably 65 to 75% by weight. The propylene / ethylene random copolymer component (A-2) is 15 to 50% by weight, preferably 20 to 40% by weight, and more preferably 25 to 35% by weight. When the proportion of the crystalline polypropylene component (A-1) is less than 50% by weight, the fluidity of the resin composition for seamless automotive interior parts is poor. On the other hand, when the proportion of the crystalline polypropylene component (A-1) exceeds 85% by weight, the impact property is deteriorated.
In the present invention, it is necessary that the ratio of the component (A-1) and the component (A-2) be in the above range, whereby a molded product having an excellent balance of fluidity, appearance and impact properties. The resin composition for seamless automobile interior parts of the present invention can be obtained.

  The MFR (230 ° C., load 21.18 N) of the entire propylene / ethylene block copolymer (A) of the present invention is preferably 10 to 40 g / 10 minutes, more preferably 15 to 30 g / 10 minutes. When the MFR of the entire propylene / ethylene block copolymer (A) is in the above range, a material having a balance between fluidity and appearance can be obtained.

2. Propylene / ethylene block copolymer (B)
The propylene / ethylene block copolymer (B) used in the present invention can be obtained by a polymerization method including a propylene polymerization step and a propylene / ethylene random copolymerization step, a crystalline polypropylene component (B-1) and propylene / ethylene. It is a block copolymer containing a random copolymer component (B-2).

(1) Crystalline polypropylene component (B-1)
The crystalline polypropylene component (B-1) is preferably a homopolymer of crystalline propylene, but crystals obtained by copolymerizing a small amount of other comonomer with propylene within a range not significantly impairing the crystallinity. Copolymer may be used. The crystallinity of the component (B-1) is usually 90% or more, preferably 95 to 100% as an isotactic index (insoluble matter by boiling n-heptane extraction). When the crystallinity is small, the rigidity of the resin composition for seamless automobile interior parts is lowered.

Examples of the comonomer include α-olefins other than propylene such as ethylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene and 4-methyl-1-pentene, styrene, vinylcyclopentene and vinylcyclohexane. And vinyl compounds such as vinyl norbornane. Two or more of these may be copolymerized.
The amount of the comonomer when copolymerizing the comonomer with propylene is about 3% by weight or less based on the total weight of the component (B-1).

The MFR (230 ° C., load 21.18 N) of the crystalline polypropylene component (B-1) is 5 to 45 g / 10 minutes, preferably 10 to 35 g / 10 minutes, and more preferably 15 to 30 g / 10. Minutes. When the MFR of the component (B-1) is less than 5 g / 10 minutes, there arises a disadvantage that the molding processability of the resin composition is inferior when the resin composition for seamless automotive interior parts is injection molded. On the other hand, if it exceeds 45 g / 10 minutes, the vibration welding strength is lowered, resulting in poor deployment of the airbag.
In the present invention, it is necessary that the MFR of the component (B-1) is in the above range, whereby the resin composition for a seamless automotive interior part according to the present invention is a seamless automotive interior part having excellent vibration welding strength. You can get things.

  In the MFRB1 of the crystalline polypropylene component (B-1), the ratio (MFRB1 / MFRA1) of the crystalline polypropylene component (A-1) to MFRA1 is preferably 0.5 or less, and more preferably 0.3 or less. Within this range, the vibration welding strength and appearance of the resin composition for seamless automotive interior parts are improved.

(2) Propylene / ethylene random copolymer component (B-2)
The propylene / ethylene random copolymer component (B-2) is a rubbery component obtained by random copolymerization of propylene and ethylene. (B-2) includes linear α-olefins such as butene-1, pentene-1, and hexene-1, branched α-olefins such as 3-methyl-1-butene and 4-methyl-1-pentene. Structural units derived from other monomers such as may be contained.

The ethylene content of the propylene / ethylene random copolymer component (B-2) is preferably 20 to 70% by weight, more preferably 25 to 50% by weight, and particularly preferably 30 to 45% by weight. Within this range, the impact properties of the resin composition for seamless automotive interior parts will be good.
Here, the ethylene content in the propylene / ethylene random copolymer component (B-2) is a value measured by a method described later.
The intrinsic viscosity [η] of the propylene / ethylene random copolymer component (B-2) is preferably 2.5 to 9.0 dl / g, more preferably 2.5 to 8.5 dl / g, More preferably, it is 2.5-7.0 dl / g, Most preferably, it is 3.0-6.5 dl / g. If [η] is less than 2.5 dl / g, a flow mark may be generated on the interior parts of the seamless automobile and the appearance may be inferior. If it exceeds 9.0 dl / g, the unmelted material at the time of molding becomes lumpy. This may impair the appearance of seamless automobile interior parts.
Here, [η] in the propylene / ethylene random copolymer component (B-2) is measured in tetralin at 135 ° C. of the component (fraction 1) eluted at 40 ° C. or less in the temperature rising elution fractionation described later. Value.

(3) Physical properties of propylene / ethylene block copolymer (B) In the propylene / ethylene block copolymer (B) used in the resin composition for seamless automotive interior parts of the present invention, the crystalline polypropylene component (B-1) and The proportion of the propylene / ethylene random copolymer component (B-2) is 70 to 95% by weight of the crystalline polypropylene component (B-1), preferably 70 to 94% by weight, more preferably 70 to 93% by weight, More preferably, it is 75 to 93 weight%, Most preferably, it is 78 to 91 weight%. 5-30% by weight of the propylene / ethylene random copolymer component (B-2), preferably 6-30% by weight, more preferably 7-30% by weight, still more preferably 7-25% by weight, and particularly preferably 9%. ~ 22% by weight. When the proportion of the crystalline polypropylene component (B-1) is less than 70% by weight, the fluidity of the resin composition for seamless automotive interior parts is inferior. On the other hand, when the proportion of the crystalline polypropylene component (B-1) exceeds 95% by weight, the impact property is lowered.
In the present invention, the ratio of the component (B-1) and the component (B-2) needs to be in the above range, and thereby, the seamless automobile interior part having excellent balance between fluidity and appearance. The resin composition for seamless automobile interior parts of the present invention can be obtained.

  Further, the MFR (230 ° C., load 21.18 N) of the entire propylene / ethylene block copolymer (B) of the present invention is preferably 5 to 40 g / 10 minutes, more preferably 7 to 40 g / 10 minutes, still more preferably. Is 10 to 40 g / 10 min, particularly preferably 15 to 30 g / 10 min. When the MFR of the propylene / ethylene block copolymer (B) is in the above range, the resin composition for seamless automotive interior parts is excellent in the balance of vibration welding strength and fluidity.

(4) Analytical method of physical properties of propylene / ethylene block copolymer (A), (B) Ratio of propylene / ethylene random copolymer portion (rubber component) of propylene / ethylene block copolymer (A) (Wc) The ethylene content in the rubber component is measured by the following procedure using the following apparatus and conditions.

(A) Analytical device to be used (i) Cross fractionation device CFC T-100 (abbreviated as CFC) manufactured by Dia Instruments
(Ii) Fourier transform infrared absorption spectrum analysis FT-IR, Perkin Elmer 1760X
A fixed wavelength infrared spectrophotometer attached as a CFC detector is removed and an FT-IR is connected instead, and this FT-IR is used as a detector. The transfer line from the outlet of the solution eluted from the CFC to the FT-IR is 1 m long, and the temperature is maintained at 140 ° C. throughout the measurement. The flow cell attached to the FT-IR has an optical path length of 1 mm and an optical path width of 5 mmφ, and the temperature is maintained at 140 ° C. throughout the measurement.
(Iii) Gel permeation chromatography (GPC)
The GPC column in the latter part of the CFC is used by connecting three AD806MS manufactured by Showa Denko KK in series.

(B) CFC measurement conditions (i) Solvent: orthodichlorobenzene (ODCB)
(Ii) Sample concentration: 4 mg / ml
(Iii) Injection volume: 0.4 ml
(Iv) Crystallization: The temperature is lowered from 140 ° C. to 40 ° C. over about 40 minutes.
(V) Sorting method:
The fractionation temperature at the time of temperature-raising elution fractionation is 40, 100, and 140 ° C., and the fraction is separated into three fractions in total. The elution ratio (unit weight%) of the component eluting at 40 ° C. or lower (fraction 1), the component eluting at 40 to 100 ° C. (fraction 2), and the component eluting at 100 to 140 ° C. (fraction 3) is W40. , W100 and W140. W40 + W100 + W140 = 100. Moreover, each fractionated fraction is automatically transported to the FT-IR analyzer as it is.
(Vi) Solvent flow rate during elution: 1 ml / min

(C) Measurement conditions of FT-IR After elution of the sample solution from GPC at the latter stage of the CFC starts, FT-IR measurement is performed under the following conditions, and GPC-IR data is collected for each of the above-described fractions 1 to 3. .
(I) Detector: MCT
(Ii) Resolution: 8 cm ⁻¹
(Iii) Measurement interval: 0.2 minutes (12 seconds)
(Iv) Number of integrations per measurement: 15 times

(D) Post-processing and analysis of measurement results The elution amount and molecular weight distribution of components eluted at each temperature are determined using the absorbance at 2945 cm ⁻¹ obtained by FT-IR as a chromatogram. The elution amount is normalized so that the total elution amount of each elution component is 100%. Conversion from the retention volume to the molecular weight is performed using a calibration curve prepared in advance with standard polystyrene.
Standard polystyrenes used are the following brands manufactured by Tosoh Corporation.
F380, F288, F128, F80, F40, F20, F10, F4, F1, A5000, A2500, A1000.
A calibration curve is prepared by injecting 0.4 ml of a solution dissolved in ODCB (containing 0.5 mg / ml BHT) so that each is 0.5 mg / ml. The calibration curve uses a cubic equation obtained by approximation by the least square method. Conversion to molecular weight uses a general-purpose calibration curve with reference to “Size Exclusion Chromatography” written by Sadao Mori (Kyoritsu Shuppan). The following numerical values are used for the viscosity equation ([η] = K × Mα) used at that time.
(I) Calibration curve using standard polystyrene K = 0.000138, α = 0.70
(Ii) Sample measurement of propylene / ethylene block copolymer K = 0.0000103, α = 0.78
The ethylene content distribution (distribution of ethylene content along the molecular weight axis) of each eluted component is a ratio of the absorbance of 2956 cm ⁻¹ and the absorbance of 2927 cm ⁻¹ obtained by FT-IR, and is obtained by using polyethylene, polypropylene, or ¹³ Converted to ethylene content (% by weight) using a calibration curve prepared in advance using ethylene-propylene rubber (EPR) and mixtures thereof whose ethylene content is known by C-NMR measurement, etc. Ask.

(E) Propylene / ethylene random copolymer component ratio (Wc)
The ratio (Wc) of the propylene / ethylene random copolymer component in the propylene / ethylene block copolymer in the present invention is theoretically defined by the following formula (I), and is determined by the following procedure.
Wc (weight%) = W40 × A40 / B40 + W100 × A100 / B100 (I)
In formula (I), W40 and W100 are the elution ratios (unit: weight%) in each of the above-mentioned fractions, and A40 and A100 are the average ethylene content of actual measurement in each fraction corresponding to W40 and W100. B40 and B100 are the ethylene content (unit: wt%) of the propylene / ethylene random copolymer component contained in each fraction. A method for obtaining A40, A100, B40, and B100 will be described later.

  The meaning of the formula (I) is as follows. That is, the first term on the right side of the formula (I) is a term for calculating the amount of the propylene / ethylene random copolymer component contained in fraction 1 (portion soluble at 40 ° C.). When fraction 1 contains only a propylene / ethylene random copolymer component and no crystalline polypropylene component, W40 contributes to the content of propylene / ethylene random copolymer component derived from fraction 1 as it is in the whole However, since fraction 1 contains components derived from propylene / ethylene random copolymer components as well as small amounts of crystalline polypropylene components (components with extremely low molecular weight and atactic polypropylene), It is necessary to correct. Therefore, by multiplying W40 by A40 / B40, the amount derived from the propylene / ethylene random copolymer component in fraction 1 is calculated.

  For example, when the average ethylene content (A40) of fraction 1 is 30% by weight and the ethylene content (B40) of the propylene / ethylene random copolymer contained in fraction 1 is 40% by weight, / 40 = 3/4 (that is, 75% by weight) is derived from a propylene / ethylene random copolymer, and 1/4 is derived from a crystalline polypropylene component. Thus, the operation of multiplying A40 / B40 in the first term on the right side means that the contribution of the propylene / ethylene random copolymer is calculated from the weight% (W40) of fraction 1. The same applies to the second term on the right side. For each fraction, the propylene / ethylene random copolymer component content is obtained by calculating and adding the contribution of the propylene / ethylene random copolymer.

(I) As described above, the average ethylene contents corresponding to fractions 1 and 2 obtained by CFC measurement are A40 and A100, respectively (the unit is% by weight). A method for obtaining the average ethylene content will be described later.

(Ii) The ethylene content corresponding to the peak position in the differential molecular weight distribution curve of fraction 1 is defined as B40 (unit is% by weight). Fraction 2 is considered to be substantially defined as B100 = 100 in the present invention because it is considered that the rubber part is completely eluted at 40 ° C. and cannot be defined with the same definition. B40 and B100 are the ethylene content of the propylene / ethylene random copolymer component contained in each fraction, but it is practically impossible to obtain this value analytically. This is because there is no means for completely separating and separating the crystalline polypropylene component and the propylene / ethylene random copolymer mixed in the fraction.
As a result of examination using various model samples, it was found that B40 can explain the effect of improving the material properties well by using the ethylene content corresponding to the peak position of the differential molecular weight distribution curve of fraction 1. It was. Further, B100 has crystallinity derived from ethylene chain, and the amount of propylene / ethylene random copolymer contained in these fractions is relative to the amount of propylene / ethylene random copolymer contained in fraction 1. For the reason of two points, the approximation to 100 is closer to the actual situation and hardly causes an error in calculation. Therefore, analysis is performed with B100 = 100.

(Iii) For the above reasons, the ratio (Wc) of the propylene / ethylene random copolymer component is determined according to the following formula.
Wc (weight%) = W40 × A40 / B40 + W100 × A100 / 100 (II)
That is, W40 × A40 / B40, which is the first term on the right side of the formula (II), indicates the content (% by weight) of propylene / ethylene random copolymer having no crystallinity, and W100 × A100 / 100, which is the second term. Indicates the content (wt%) of propylene / ethylene random copolymer component having crystallinity.
Here, average ethylene content A40, A100 of each fraction 1 and 2 obtained by B40 and CFC measurement is calculated | required as follows.
The ethylene content corresponding to the peak position of the differential molecular weight distribution curve is B40. In addition, the sum of the products of the weight ratio for each data point and the ethylene content for each data point, which is captured as data points during measurement, is the average ethylene content A40 of fraction 1. The average ethylene content A100 of fraction 2 is determined in the same manner.

The significance of setting the three types of fractionation temperatures is as follows. In the CFC analysis of the present invention, polymers having no crystallinity at 40 ° C. (for example, most of propylene / ethylene random copolymers, or extremely low molecular weight components and atactic components among crystalline polypropylene component portions) ) Only is necessary and sufficient temperature fractionation. 100 ° C. means a component that is insoluble at 40 ° C. but becomes soluble at 100 ° C. (for example, a component having crystallinity due to a chain of ethylene and / or propylene in a propylene / ethylene random copolymer, and a crystal The temperature is necessary and sufficient for eluting only the low-crystalline crystalline polypropylene component). 140 ° C. means a component that is insoluble at 100 ° C. but becomes soluble at 140 ° C. (for example, a component having particularly high crystallinity in a crystalline polypropylene component and an extremely high molecular weight in a propylene / ethylene random copolymer) The temperature is necessary and sufficient to elute only the component having extremely high ethylene crystallinity and recover the entire amount of the propylene-based block copolymer used for the analysis.
W140 does not contain any propylene / ethylene random copolymer component, or even if it is present, it is extremely small and can be substantially ignored. Therefore, the ratio of propylene / ethylene random copolymer and propylene / ethylene random copolymer are not significant. Excluded from the calculation of the ethylene content of the polymer.

(F) Ethylene content of propylene / ethylene random copolymer component The ethylene content of the propylene / ethylene random copolymer component in the propylene / ethylene block copolymer according to the present invention is determined by the following formula: It is requested from.
Ethylene content (% by weight) of propylene / ethylene random copolymer component = (W40 × A40 + W100 × A100) / Wc
(Wc is the proportion (% by weight) of the propylene / ethylene random copolymer component obtained previously.)

  In the present invention, by using two kinds of propylene / ethylene block copolymers (A) and (B) which are different from each other as described above at a specific ratio, the molecular weight distribution is broadened, and the low molecular weight component and the high molecular weight are increased. The ratio of components increases relatively. It is considered that the low molecular weight component dissolves quickly at the time of vibration welding to increase the welding speed, while the high molecular weight component has a molecular chain entanglement effect, and as a result, the vibration welding strength is improved.

3. Copolymer rubber of ethylene and α-olefin having 3 to 6 carbon atoms (C)
The copolymer rubber (C) of ethylene and an α-olefin having 3 to 6 carbon atoms used in the resin composition for seamless automobile interior parts of the present invention is a random copolymer of ethylene and an α-olefin having 3 to 6 carbon atoms. A polymer having a rubber-like property. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1-butene and 4-methyl-1-pentene. Two or more of these may be copolymerized. Preferred are propylene and 1-butene.
In the present invention, the α-olefin content is 10 to 60% by weight, preferably 15 to 50% by weight, based on the total weight of the copolymer rubber (C) of ethylene and an α-olefin having 3 to 6 carbon atoms. % Is preferable in that rubber-like properties are easily exhibited.

The copolymer rubber (C) of ethylene and α-olefin having 3 to 6 carbon atoms of the present invention can be produced by copolymerizing ethylene and α-olefin as monomers in the presence of a catalyst. Examples of the catalyst include titanium compounds such as titanium halides, organoaluminum-magnesium complexes such as alkylaluminum-magnesium complexes, so-called Ziegler-type catalysts such as alkylaluminum and alkylaluminum chloride, and the like described in WO91 / 04257. A metallocene compound catalyst or the like can be used.
As the polymerization method, any method can be adopted as long as the catalyst component and each monomer come into contact efficiently. Specifically, a manufacturing method such as a slurry method, a gas phase fluidized bed method or a solution method in the presence of these catalysts, or a high pressure bulk polymerization method at a pressure of 200 kg / cm ² or more and a polymerization temperature of 100 ° C. or more. Can be polymerized. Preferred production methods include high-pressure bulk polymerization and solution methods.

  Specific examples of the copolymer rubber (C) of ethylene and an α-olefin having 3 to 6 carbon atoms of the present invention include, for example, an ethylene / propylene copolymer (EPR) and an ethylene / butene copolymer (EBR). And ethylene-hexene copolymer (EHR). In the present invention, the copolymer rubber (C) of these ethylene and a C3-C6 α-olefin is not limited to one type, and is a mixture of two or more different types such as density and MFR. It may be used.

  Examples of commercially available products that can be used as the copolymer rubber (C) of ethylene and an α-olefin having 3 to 6 carbon atoms of the present invention include EP series manufactured by JSR, Tuffmer P series and Tuffmer A manufactured by Mitsui Chemicals. A series can be mentioned.

In this invention, MFR (230 degreeC, load 21.18N) of the copolymer rubber (C) of ethylene and C3-C6 alpha olefin is 0.5-10 g / 10min, Preferably it is 1 It is necessary to be 9 g / 10 minutes, more preferably 2 to 7 g / 10 minutes. When the MFR is less than 0.5 g / 10 minutes, the fluidity of the resin composition for seamless automobile interior parts of the present invention is lowered, and when it exceeds 10 g / 10 minutes, the appearance of the seamless automobile interior parts deteriorates. MFR can be appropriately adjusted during polymerization by controlling the molecular weight such as hydrogen and controlling the rate of β hydrogen abstraction.
In the present invention, when the MFR of the copolymer rubber (C) of ethylene and an α-olefin having 3 to 6 carbon atoms is within the above range, the fluidity can be improved while maintaining the appearance. In addition, the resin composition for seamless automotive interior parts of the present invention having a good balance including impact properties and vibration welding strength can be obtained.

4). Copolymer rubber of ethylene and α-olefin having 7 to 18 carbon atoms (D)
The copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms used in the resin composition for seamless automobile interior parts of the present invention is a random copolymer of ethylene and an α-olefin having 7 to 18 carbon atoms. A polymer having a rubber-like property. Examples of the α-olefin include 1-heptene, 1-octene, 1-decene and the like. Two or more of these may be copolymerized. 1-octene is preferred.
In the present invention, the α-olefin content is 10 to 60% by weight, preferably 15 to 50% by weight based on the total weight of the copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms. % Is preferable in that rubber-like properties are easily exhibited.

  The copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms used in the resin composition for seamless automotive interior parts of the present invention is a copolymer rubber containing ethylene and α-olefin in the presence of a catalyst. It can be produced by polymerization. Examples of the catalyst include titanium compounds such as titanium halides, organoaluminum-magnesium complexes such as alkylaluminum-magnesium complexes, so-called Ziegler-type catalysts such as alkylaluminum and alkylaluminum chloride, and the like described in WO91 / 04257. A metallocene compound catalyst or the like can be used.

As the polymerization method, any method can be adopted as long as the catalyst component and each monomer come into contact efficiently. Specifically, a manufacturing method such as a slurry method, a gas phase fluidized bed method or a solution method in the presence of these catalysts, or a high pressure bulk polymerization method at a pressure of 200 kg / cm ² or more and a polymerization temperature of 100 ° C. or more. Can be polymerized. Preferred production methods include high-pressure bulk polymerization and solution methods.

  Specific examples of the copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms of the present invention include, for example, ethylene / octene copolymer (EOR). In the present invention, the copolymer rubber (D) of these ethylene and an α-olefin having 7 to 18 carbon atoms is not limited to one type, but may be a mixture of two or more different types such as density and MFR. It may be used.

  Examples of commercially available products that can be used as the copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms according to the present invention include DuPont Dow's Engage EG Series and Affinity Series, Mitsui Chemicals' Toughmer H A series can be mentioned.

In the present invention, the MFR (230 ° C., load 21.18 N) of the copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms is 0.5 to 10 g / 10 minutes, preferably 1 to It is necessary to be 9 g / 10 minutes, more preferably 2 to 7 g / 10 minutes. If the MFR is less than 0.5 g / 10 minutes, the fluidity is insufficient, and if it exceeds 10 g / 10 minutes, low temperature impact is reduced. MFR can be appropriately adjusted during polymerization by controlling the molecular weight such as hydrogen and controlling the rate of β hydrogen abstraction.
In the present invention, when the MFR of the copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms is within the above range, impact properties can be improved, impact properties and vibration welding. The resin composition for seamless automobile interior parts of the present invention having a good balance including strength can be obtained.

5. Inorganic filler (E)
The inorganic filler used in the present invention may be in any shape such as granular, plate-like, rod-like, fiber-like, whisker-like.

  Examples of the inorganic filler (E) include oxides such as silica, diatomaceous earth, barium ferrite, beryllium oxide, pumice and pumice balun, hydroxides such as aluminum hydroxide, magnesium hydroxide and basic magnesium carbonate, and carbonic acid. Carbonates such as calcium, magnesium carbonate, dolomite, dosonite, sulfates or sulfites such as calcium sulfate, barium sulfate, ammonium sulfate, calcium sulfite, talc, clay, mica, glass fiber, glass balloon, glass beads, calcium silicate, Silicates such as montmorillonite and bentonite, carbons such as carbon black, graphite, carbon fiber, carbon hollow sphere, molybdenum sulfide, boron fiber, zinc borate, barium metaborate, calcium borate, sodium borate, magnesium oxide Sulfates, such as various types of metal fibers can be mentioned.

These inorganic fillers may be used singly or in combination of two or more. Among these, talc, mica, calcium carbonate, and glass fiber are preferable. In the present invention, by using an inorganic filler, the flexural modulus of the resin composition for seamless automotive interior parts can be improved, the linear expansion coefficient can be reduced, and the dimensional stability can be improved.
Among these inorganic fillers, talc is particularly preferable from the viewpoint of the balance between physical properties and cost. Inorganic fillers are various organic titanate coupling agents, organic silane coupling agents, unsaturated carboxylic acids, or anhydrides thereof for the purpose of improving adhesiveness or dispersibility with (A) and (B). You may use what surface-treated by the modified polyolefin which grafted the thing, a fatty acid, a fatty acid metal salt, fatty acid ester, etc.
The size of the inorganic filler is not particularly limited.For example, in the case of talc, from the viewpoint of physical properties such as rigidity of molded article obtained, impact resistance, vibration welding strength, whitening resistance with scratches, weld appearance, and uneven gloss. The average particle diameter obtained by the laser diffraction method is 1 to 6 μm, and the average aspect ratio is 4 or more. In particular, those obtained by processing and pulverization are particularly preferable in terms of physical properties and rigidity.

6). In the present invention, the blending ratios of the components (A) to (E) constituting the composition are based on 100% by weight of the total amount of (A) to (E), and both propylene and ethylene block are blended. The polymer (A) is 10 to 50% by weight, preferably 15 to 45% by weight, more preferably 20 to 40% by weight, and the propylene / ethylene block copolymer (B) is 25 to 55% by weight, preferably 30 to 30% by weight. 52% by weight, more preferably 35 to 50% by weight, copolymer rubber (C) of ethylene and an α-olefin having 3 to 6 carbon atoms is 5 to 15% by weight, preferably 6 to 13% by weight, more preferably 7 to 11% by weight, copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms is 3 to 10% by weight, preferably 3 to 9% by weight, more preferably 3 to 8% by weight. Inorganic filler (E) is 5-2 Wt%, preferably 8-18 wt%, more preferably 10 to 17 wt%.

The critical significance of the blending ratio of the components (A) to (E) described above is as follows.
(1) When the proportion of the propylene / ethylene block copolymer (A) is less than 10% by weight, the fluidity of the resin composition for seamless automotive interior parts is lowered, and when it exceeds 50% by weight, the vibration welding strength is reduced. .
(2) When the proportion of the propylene / ethylene block copolymer (B) is less than 25% by weight, the vibration welding strength is lowered, and when it exceeds 55% by weight, the fluidity is lowered.
(3) When the ratio of the copolymer rubber (C) of ethylene and C3-C6 α-olefin is less than 5% by weight, the appearance and impact properties deteriorate, and when it exceeds 15% by weight, fluidity Decreases.
(4) When the ratio of the copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms is less than 3% by weight, the impact property is lowered, and when it exceeds 10% by weight, the fluidity is lowered. .
(5) If the proportion of the inorganic filler (E) is less than 5% by weight, the rigidity decreases, and if it exceeds 20% by weight, the vibration welding strength decreases.

  In the examination by the present inventors, it was confirmed that fracture occurred at the interface between the resin component (mainly crystalline polypropylene component) as a matrix and the inorganic filler in the peel test of the vibration welded part. And when there was much quantity of an inorganic filler, since the origin of destruction increased, it was estimated that vibration welding strength falls. Therefore, in the present invention, in consideration of making the number of starting points of fracture below a critical value, the above-mentioned blending ratio as an amount that exerts an imparting effect such as rigidity and heat resistance, which is the original purpose of blending the inorganic filler Determined.

7). Other additives In the resin composition of the present invention, an antioxidant (phenolic, sulfur-based, phosphorus-based, lactone-based, vitamin-based, etc.), weather stabilizer, ultraviolet absorber (benzotriazole-based) is optionally added. , Tridiamine, anilide, benzophenone, etc.), heat stabilizer, light stabilizer (hindered amine, benzoate, etc.), antistatic agent, nucleating agent, pigment, adsorbent (metal oxide (zinc oxide, magnesium oxide) Etc.), metal chlorides (iron chloride, calcium chloride, etc.), hydrotalcite, aluminates, etc.), additives such as lubricants (metal soaps, fatty acid amides, silicone oils, silicone gums, etc.) .

8). Manufacture of resin composition for seamless automobile interior parts The resin composition for seamless automobile interior parts of the present invention is produced by mixing the above-mentioned components in the above proportions, such as a single screw extruder, a twin screw extruder, etc. It can be produced by kneading at a resin temperature of 180 ° C. to 250 ° C., for example, using a normal kneader such as an extruder, Banbury mixer, roll, Brabender plastograph, kneader. Among these kneaders, it is preferable to produce using an extruder, particularly a twin screw extruder.
Mixing and kneading of the components may be performed simultaneously or may be performed separately. As a method of divided addition, propylene / ethylene block copolymer (A) or propylene / ethylene block copolymer (B) and inorganic filler (E) are kneaded, and then a copolymer of ethylene and α-olefin. Method of adding rubber (C), (D), (A) and (B) and (E) in advance, kneading the concentration of (E) to a high concentration to obtain a master batch, which is separately (A) And a method of kneading while diluting with (B), (C), (D) or the like, or (A) and (B) and (E), (A) and (B) and (C), (D) in advance And kneading all together, and finally kneading all together, etc., and can be molded by the same method.

9. Manufacture of seamless automobile interior parts The resin composition obtained by the above-described method preferably has an MFR of 6 to 20 g / 10 minutes, more preferably 8 to 18 g / 10 minutes from the viewpoint of moldability. preferable. And since the resin composition of this invention is excellent in rigidity and impact resistance, and vibration welding strength is high, it is suitable for seamless vehicle interior components, especially a seamless instrument panel.
For the production of seamless automobile interior parts such as seamless instrument panels, the resin composition of the present invention can be used by a known method such as an injection molding method.
Since the obtained seamless automobile interior part part, for example, the instrument panel part and the airbag cover part can be formed integrally, a seamless instrument panel is obtained.
In that case, the vibration welding strength (maximum point load) when a seamless automobile interior part, for example, a seamless instrument panel and an airbag kit is fixed by vibration welding, is preferably 46 N or more from a practical viewpoint. 48N or more, more preferably 50N or more.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples unless it exceeds the gist. In addition, the measuring method used in the Examples, propylene / ethylene block copolymer (A), propylene / ethylene block copolymer (B), copolymer rubber of ethylene and an α-olefin having 3 to 6 carbon atoms Materials such as (C), a copolymer rubber (D) of ethylene and an α-olefin having 7 to 18 carbon atoms, and an inorganic filler (E) are as follows.

1. Measurement method (1) MFR: Measured at a temperature of 230 ° C. and a load of 21.18 N according to JIS K7210.
(2) Vibration welding strength (maximum point load): A 120 × 15 × 2 mm test piece and a 120 × 15 × 2 mm test piece separately molded using a thermo-run manufactured by Mitsubishi Chemical Co., Ltd. Vibration welding was performed.
Here, vibration welding was performed using Branson 2800J-DC under conditions of a frequency of 240 Hz, an amplitude of 1.5 mm, a welding time of 5 seconds, a welding thickness of 0.5 mm, and a welding pressure of 4.8 MPa.
The vibration welding strength (maximum point load) was measured by pulling the welding surface of the vibration welding sample to peel off, and the maximum point load at that time was defined as the vibration welding strength. The tensile test was performed at a distance between chucks of 60 mm and a tensile speed of 20 mm / min. The unit of this vibration welding strength (maximum point load) is N.
(3) Flexural modulus: measured according to JIS K7171 using a test piece having a thickness of 4 mm. The test temperature was 23 ° C.
(4) IZOD impact strength: Measured according to JIS K7110 using a test piece having a thickness of 4 mm. The test temperature was 23 ° C.
(5) Appearance: From the gate to the portion where the flow mark is generated, the occurrence of the flow mark is visually observed in a 350 mm × 100 mm × 2 mm molded sheet formed using a mold having a film gate with a width of 2 mm on the short side. The distance was measured and judged according to the following criteria.
○: The flow mark is 200 mm or more from the gate ×: The flow mark is less than 200 mm from the gate

2. Materials (1) Propylene / ethylene block copolymer (A), (B)
PP1: MFRh 120 g / 10 min, Cv 30 wt%, Gv 35 wt%, [η] 3.2 dl / g, MFR 30 g / 10 min PP2: MFRh 30 g / 10 min, Cv 30 wt%, Gv 33 wt%, [η] 3.5 dl / g, MFR 8 g / 10 min PP3: MFRh 150 g / 10 min, Cv 30 wt%, Gv 35 wt%, [η] 3.0 dl / g, MFR 35 g / 10 min PP4: MFRh 50 g / 10 min, Cv 30 wt%, Gv 35 wt%, [ η] 3.2 dl / g, MFR 15 g / 10 min PP5: MFRh 19 g / 10 min, Cv 9 wt%, Gv 45 wt%, [η] 8.2 dl / g, MFR 9 g / 10 min where MFRh is the crystalline polypropylene component MFR, Cv is the proportion of propylene / ethylene random copolymer component, Gv is propylene / ethylene lander The ethylene content of the copolymer component, [eta] is the intrinsic viscosity of the propylene-ethylene random copolymer component, MFR represents the MFR of the whole propylene-ethylene block copolymer.

(2) Copolymer rubber of ethylene and α-olefin having 3 to 6 carbon atoms (C)
C1: Mitsui Chemicals Co., Ltd. (MFR 2 g / 10 min ethylene / butene copolymer)
C2: Mitsui Chemicals (MFR 1 g / 10 min ethylene / butene copolymer)
C3: Made by Mitsui Chemicals (MFR 6 g / 10 min ethylene / butene copolymer)
C4: Made by Mitsui Chemicals (MFR 11 g / 10 min ethylene butene copolymer)

(3) Copolymer rubber of ethylene and α-olefin having 7 to 18 carbon atoms (D)
D1: manufactured by DuPont Dow (MFR 2 g / 10 min ethylene-octene copolymer)
D2: DuPont Dow (MFR 1 g / 10 min ethylene octene copolymer)
D3: manufactured by DuPont Dow (MFR 6 g / 10 min ethylene-octene copolymer)
D4: manufactured by DuPont Dow (MFR 11 g / 10 min ethylene-octene copolymer)

(4) Inorganic filler (E)
Talc: manufactured by Fuji Talc Kogyo Co., Ltd. (average particle size 5 μm)

[Example 1]
As shown in Table 1, propylene / ethylene block copolymer (A) (PP1) 26% by weight, propylene / ethylene block copolymer (B) (PP2) 45% by weight, ethylene and an α-olefin having 3 to 6 carbon atoms Copolymer rubber (C) (C1) 8% by weight, copolymer rubber (D) (D1) 5% by weight of ethylene and an α-olefin having 7 to 18 carbon atoms, inorganic filler (E) ( 16% by weight of talc), mixed for 5 minutes with a Henschel mixer, and then kneaded and granulated at a set temperature of 210 ° C. with a twin-screw kneader (Kobe Steel Corporation: 2FCM) to obtain a resin composition It was. Thereafter, various test pieces were prepared at a molding temperature of 210 ° C. with an injection molding machine having a clamping pressure of 100 tons, and the molded body was measured according to the various measurement methods described above. The evaluation results are shown in Table 1.

[Examples 2-6, Comparative Examples 1-9]
The aforementioned materials were blended in the proportions shown in Tables 1 and 2, and a resin composition was obtained in the same manner as in Example 1.
The physical property evaluation similar to Example 1 was performed about the obtained resin composition. The evaluation results are shown in Tables 1 and 2.

As can be seen from Tables 1 and 2, in Examples 1 to 6, all of the obtained resin compositions were excellent in moldability, rigidity, impact resistance, appearance, and vibration welding characteristics.
On the other hand, in Comparative Examples 1 to 9, the obtained resin compositions lacked at least a part of the requirements of the present invention, and some of the above-described characteristics were inferior to those of Examples.

  As is clear from the above, according to the present invention, the airbag operation can be seamlessly provided with the airbag system because of excellent rigidity, impact resistance, appearance, and vibration welding characteristics with the airbag kit. It is possible to provide a resin composition for seamless automobile interior parts, for example, seamless instrument panels, which can be reliably deployed at times, and seamless automobile interior parts obtained from the resin compositions, for example, seamless instrument panels. Extremely expensive.

Claims (6)

  A propylene / ethylene block comprising a crystalline polypropylene component of 50 to 85% by weight and a propylene / ethylene random copolymer component of 15 to 50% by weight with a melt flow rate (230 ° C., load of 21.18 N) of 50 to 130 g / 10 min. Copolymer (A), Melt flow rate (230 ° C., Load 21.18 N) of crystalline polypropylene component 70 to 95% by weight of 5 to 45 g / 10 min and propylene / ethylene random copolymer component 5 to 30% by weight A propylene / ethylene block copolymer (B) comprising: a copolymer of ethylene having a melt flow rate (230 ° C., load 21.18 N) of 0.5 to 10 g / 10 min and an α-olefin having 3 to 6 carbon atoms. Polymer rubber (C), ethylene having a melt flow rate (230 ° C., load 21.18 N) of 0.5 to 10 g / 10 min It consists of a copolymer rubber (D) with an α-olefin having a prime number of 7 to 18 and an inorganic filler (E), and the content ratio of each component is (A) 10 to 50% by weight, (B) 25-55 wt%, (C) 5-15 wt%, (D) 3-10 wt%, (E) 5-20 wt% (however, the total amount of (A)-(E) is 100 wt%) %).) A resin composition for seamless automobile interior parts.   The resin composition for seamless automobile interior parts according to claim 1, wherein the vibration welding strength (maximum point load) when the seamless automobile interior parts and the airbag kit are fixed by vibration welding is 46 N or more. .   The resin composition for seamless automotive interior parts according to claim 1 or 2, wherein the melt flow rate (230 ° C, load 21.18N) is 6 to 20 g / 10 min.   The resin composition for a seamless automotive interior part according to any one of claims 1 to 3, wherein the seamless automotive interior part is a seamless instrument panel.   A seamless automobile interior part formed by molding the resin composition according to claim 1.   The seamless instrument panel formed by shape | molding the resin composition of Claim 4.