JP7362342B2 - Filler-containing polypropylene resin composition and automotive exterior parts - Google Patents

Description

The present invention relates to a filler-containing polypropylene resin composition that exhibits excellent physical properties such as rigidity, impact resistance, and heat resistance, as well as good jet blackness, and to automobile exterior parts.

Molded products obtained by injection molding polypropylene resin compositions are widely used in automobile parts and home appliance parts due to their excellent mechanical properties and moldability, as well as their relatively advantageous cost performance compared to other materials. Its use in various fields is progressing. In recent years, compositions containing rubber components such as ethylene/propylene block copolymers, ethylene/α-olefin copolymers, inorganic fillers, and various other additives have been developed to improve various physical properties. is proposed.

For example, Patent Document 1 describes a crystalline ethylene/propylene block copolymer, an elastomer, an inorganic filler, an organic phosphorus antioxidant, and a hindered phenol oxidizer that does not contain nitrogen atoms and has a molecular weight of 500 or more. A polypropylene resin composition containing an inhibitor, a hindered phenolic antioxidant containing a nitrogen atom, and a hindered amine light stabilizer having no NH bond is disclosed. It is also stated that this polypropylene resin composition is excellent in weather resistance, paintability after plasma treatment, and yellowing resistance of the painted film.

Patent Document 2 describes a propylene-ethylene block copolymer, an olefin elastomer, an inorganic filler, a black pigment, a white pigment, a hindered phenol antioxidant, an ultraviolet absorber, and a hindered amine photostabilizer. A polypropylene resin composition containing an agent is disclosed. It is also stated that this polypropylene resin composition is excellent in weather resistance, paintability after plasma treatment, and yellowing resistance of the painted film.

Patent Document 3 describes a hindered amine light stabilizer formed of polypropylene, talc, an elastomer, and a piperidine derivative having a molecular weight of 600 to 950, and a hindered amine light stabilizer having an N-H bond and a molecular weight of 1000 or more. A polypropylene resin composition containing a stabilizer, a hindered amine light stabilizer having an N--CH ₃ bond and a molecular weight of 600 or more, and a triarylphosphite heat stabilizer is disclosed. It is also described that inorganic pigments such as metal oxides, sulfides, and sulfates, and organic pigments such as phthalocyanine, quinacridone, and benzidine pigments can be blended. It is also described that this polypropylene resin composition has excellent light resistance and can be continuously injection molded for a long period of time into molded products with little change in gloss.

Patent Document 4 describes a propylene-ethylene block copolymer consisting of a crystalline polypropylene component and a propylene-ethylene random copolymer component, a propylene polymer, an ethylene-α-olefin copolymer rubber, and a polymer having a molecular weight of 700 or more. A polypropylene block copolymer composition comprising a hindered amine light stabilizer is disclosed. It is also described that coloring substances such as quinacridone, perylene, phthalocyanine, titanium oxide, and carbon black can be incorporated. This polypropylene block copolymer composition is described as being excellent in ductility, dimensional stability, surface quality, weather resistance, and prevention of fogging on the inner surface of glass.

Patent Document 5 describes a crystalline propylene block copolymer, a crystalline propylene homopolymer, an elastomeric polymer composition having a specific composition, an inorganic filler, a hindered amine weathering stabilizer, and a hindered amine-based weathering stabilizer. An automobile exterior resin composition containing a phenolic ultraviolet absorber is disclosed. This resin composition for automobile exteriors has an excellent balance of fluidity and physical properties (flexural modulus, impact resistance, hardness, embrittlement temperature, etc.), has a low heat shrinkage rate, and can be injection-molded with few flow marks and weld marks. It is stated that molded products can be easily formed.

Japanese Patent Application Publication No. 6-107897 Japanese Patent Application Publication No. 9-95592 Japanese Patent Application Publication No. 2002-012720 Japanese Patent Application Publication No. 2008-101091 Japanese Patent Application Publication No. 2005-146013

The present inventors focused on the need for a jet black appearance, which was not considered in the prior art described above, as well as excellent physical properties. That is, an object of the present invention is to provide a filler-containing polypropylene resin composition and automobile exterior parts that exhibit excellent physical properties such as rigidity, impact resistance, and heat resistance, and also exhibit good jet blackness.

As a result of intensive studies to achieve the above object, the present inventors found that a filler-containing polypropylene resin composition having a specific composition is very effective, and completed the present invention. That is, the present invention is specified by the following matters.

[1] Propylene homopolymer part (A1) 70 to 100% by mass, and ethylene-propylene copolymer part (A2) 0 to 30 mass% having an intrinsic viscosity [η] of 2.0 to 8.0 dl/g % (total of component (A1) and component (A2) is 100 mass%) 60 to 75 parts by mass of propylene polymer (A),
0 to 5 parts by mass of ethylene/α-olefin copolymer (B) (α-olefin has 3 to 10 carbon atoms),
25 to 35 parts by mass of inorganic filler (C),
As the antioxidant (D), 0.01 to 1.0 parts by mass of a hindered phenolic antioxidant (D-1) with a molecular weight of 1000 or more and a hindered phenolic antioxidant (D-2) with a molecular weight of less than 1000. ) 0.01 to 1.0 parts by mass,
As the weathering stabilizer (E), 0.01 to 0.5 parts by mass of a benzoate light stabilizer (E-1) with a molecular weight of less than 1,000 and 0.0 parts by mass of a hindered amine light stabilizer (E-2) with a molecular weight of less than 1,000. 01 to 0.5 parts by mass,
The pigment (F) includes 0.4 to 1.0 parts by mass of carbon black (F-1), 0.5 parts by mass or less of titanium oxide (F-2), and a green pigment or blue pigment (F-3). ) 0.05 to 0.5 parts by mass, and
Fatty acid metal salt (G) 0.01 to 1.0 parts by mass [However, the total amount of component (A), component (B) and component (C) is 100 parts by mass. ]
A filler-containing polypropylene resin composition.

[2] The filler-containing polypropylene resin composition according to [1], wherein the propylene polymer (A) is a propylene/ethylene block copolymer.

[3] An automobile exterior part obtained by injection molding the filler-containing polypropylene resin composition according to [1] or [2].

According to the present invention, it is possible to provide a filler-containing polypropylene resin composition and automobile exterior parts that exhibit excellent physical properties such as rigidity, impact resistance, and heat resistance, and also exhibit good jet blackness.

Since the filler-containing polypropylene resin composition of the present invention has a specific composition, it has excellent physical properties such as rigidity, impact resistance, and heat resistance. In addition, a specific amount of inorganic filler (C) and a specific amount of three types of pigments (F-1), (F-2) and (F-3) [especially pigment (F-3)] are combined. This results in a high quality jet black finish.

<Propylene polymer (A)>
The propylene polymer (A) used in the present invention is an ethylene/propylene polymer having a propylene homopolymer portion (A1) of 70 to 100% by mass and an intrinsic viscosity [η] of 2.0 to 8.0 dl/g. It is a propylene polymer consisting of a polymer portion (A2) of 0 to 30% by mass (the total of component (A1) and component (A2) is 100% by mass).

The propylene polymer (A) may be a propylene homopolymer or a propylene/ethylene block copolymer. In the case of a propylene homopolymer, the amount of the propylene homopolymer part (A1) is 100% by mass, and in the case of a propylene/ethylene block copolymer, the amount of the propylene homopolymer part (A1) is 100% by mass. less than In particular, the propylene polymer (A) is preferably a propylene/ethylene block copolymer.

In the propylene polymer (A), the amount of the propylene homopolymer portion (A1) is 70 to 100% by mass, preferably 75 to 95% by mass, and more preferably 80 to 90% by mass. The amount of the ethylene-propylene copolymer portion (A2) is 0 to 30% by weight, preferably 5 to 25% by weight, more preferably 10 to 20% by weight.

The amounts of the propylene homopolymer part (A1) and the ethylene-propylene copolymer part (A2) in the propylene polymer (A) are determined from the decane-insoluble part and the decane-insoluble part, as described in the Examples section below. It can be determined by the amount of melted part. Specifically, the decane insoluble portion is a component that is generally insoluble in n-decane solvent at room temperature (23°C), and is usually the same as the propylene homopolymer portion (A1) that occupies the propylene polymer (A). are equivalent. On the other hand, the decane soluble portion is usually equivalent to the portion other than the propylene homopolymer portion (ie, the ethylene-propylene copolymer portion (A2)).

The intrinsic viscosity [η] of the ethylene-propylene copolymer portion (A2) is 2.0 to 8.0 dl/g.

The melt flow rate (230° C., 2.16 kg load) of the propylene polymer (A) is preferably 5 to 300 g/10 minutes, more preferably 10 to 250 g/10 minutes.

The propylene polymer (A) can be produced by a known method. The propylene-ethylene block copolymer, which is a preferred embodiment of the propylene polymer (A), can be produced using, for example, an olefin polymerization catalyst containing a solid titanium catalyst component (I) and an organometallic compound catalyst component (II). A propylene block copolymer can be obtained by polymerizing propylene and then copolymerizing propylene and ethylene. The solid titanium catalyst component (I) contains, for example, titanium, magnesium, halogen and, if necessary, an electron donor. For this solid titanium catalyst component (I), known components can be used without limitation. The organometallic compound catalyst component (II) is a component containing a metal element selected from Groups 1, 2, and 13 of the periodic table. For example, a compound containing a Group 13 metal (organoaluminum compound, etc.), a complex alkylated product of a Group 1 metal and aluminum, an organometallic compound of a Group 2 metal, etc. can be used. Among these, organic aluminum compounds are preferred.

A propylene/ethylene block copolymer, which is a preferred embodiment of the propylene polymer (A), can be produced by polymerizing propylene in the presence of the above-mentioned olefin polymerization catalyst, and then copolymerizing propylene and ethylene, or by prepolymerizing them. It can be produced by a method such as polymerizing propylene in the presence of a prepolymerized catalyst obtained by using a prepolymerized catalyst, and then copolymerizing propylene and ethylene. Polymerization can be carried out in any of the batch, semi-continuous and continuous methods.

<Ethylene/α-olefin copolymer (B)>
The ethylene/α-olefin copolymer (B) used in the present invention is a copolymer of ethylene and an α-olefin having 3 to 10 carbon atoms, and is usually a random copolymer.

Specific examples of the α-olefin having 3 to 8 carbon atoms constituting the ethylene/α-olefin copolymer (B) include propylene, 1-butene, 1-pentene, 1-hexene, 3-methyl-1- Examples include butene, 4-methyl-1-pentene, 1-hexene, and 1-octene. One type of α-olefin may be used alone, or two or more types may be used in combination. Among these, 1-butene, 1-hexene, and 1-octene are preferred. As the ethylene/α-olefin copolymer (C), particularly preferred are ethylene-octene copolymers and ethylene-butene copolymers.

The ethylene content of the ethylene/α-olefin copolymer (B) is preferably 70 to 95 mol%, more preferably 75 to 95 mol%.

The melt flow rate (230° C., 2.16 kg load) of the ethylene/α-olefin copolymer (B) is preferably 0.1 to 30 g/10 minutes, more preferably 1 to 10 g/10 minutes.

The density of the ethylene/α-olefin copolymer (B) is preferably 850 to 900 g/cm ³ , more preferably 850 to 890 g/cm ³ .

<Inorganic filler (C)>
The type of inorganic filler (C) used in the present invention is not particularly limited, and various known inorganic fillers can be used. Specific examples include talc, mica, calcium carbonate, barium sulfate, glass fiber, gypsum, magnesium carbonate, magnesium oxide , and iron oxide . Further examples include metal powders or metal fibers such as zinc, copper, iron, and aluminum. These may be used alone or in combination of two or more. Among these, talc, mica, calcium carbonate, and glass fiber are preferred, and talc is particularly preferred since it has a good balance between rigidity and impact.

The average particle size of the inorganic filler (C) such as talc is usually 1 to 15 μm, preferably 1 to 6 μm. When the average particle size is below the upper limit of these ranges, it tends to be possible to maintain a good physical property balance of rigidity and impact resistance. This average particle size is a value measured by laser diffraction method.

<Antioxidant (D)>
The antioxidants (D) used in the present invention are a hindered phenolic antioxidant (D-1) with a molecular weight of 1000 or more and a hindered phenolic antioxidant (D-2) with a molecular weight of less than 1000.

The type of hindered phenolic antioxidant (D-1) having a molecular weight of 1000 or more is not particularly limited, and various known hindered phenolic antioxidants can be used. Such hindered phenolic antioxidant (D-1) is available as a commercial product. A preferred commercial product is, for example, pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by BASF Japan Co., Ltd., Irganox (registered trademark) 1010, molecular weight = 1177.7 ).

The type of hindered phenolic antioxidant (D-2) having a molecular weight of less than 1000 is not particularly limited, and various known hindered phenolic antioxidants can be used. Such hindered phenolic antioxidant (D-2) is available as a commercial product. Preferred commercial products include, for example, octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate (manufactured by BASF Japan Co., Ltd., Irganox (registered trademark) 1076, molecular weight = 530.9), Tris -(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate (manufactured by BASF Japan Co., Ltd., Irganox (registered trademark) 3114, molecular weight = 784.0).

<Weather stabilizer (E)>
The weathering stabilizers (E) used in the present invention are a benzoate light stabilizer (E-1) with a molecular weight of less than 1,000 and a hindered amine light stabilizer (E-2) with a molecular weight of less than 1,000. Note that the weathering stabilizer (E) is sometimes commercially available as an ultraviolet absorber.

The type of benzoate light stabilizer (E-1) having a molecular weight of less than 1000 is not particularly limited, and various known benzoate light stabilizers can be used. Such benzoate light stabilizer (E-1) is available as a commercial product. A preferred commercially available product is, for example, 2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate (manufactured by BASF Japan Co., Ltd., Tinuvin (registered trademark) 120, molecular weight = 438. 7).

The type of hindered amine light stabilizer (E-2) having a molecular weight of less than 1000 is not particularly limited, and various known hindered amine light stabilizers can be used. Such hindered amine light stabilizer (E-2) is available as a commercial product. Preferred commercially available products include, for example, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate (manufactured by ADEKA Co., Ltd., trade name LA-52, molecular weight =847.2), tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)butane-1,2,3,4-butanetetracarboxylate (manufactured by ADEKA Co., Ltd., trade name LA-57, Molecular weight = 792), 1,2,2,6,6-pentamethyl-4-piperidyl/tridecyl-1,2,3,4-butanetetracarboxylate (manufactured by ADEKA Co., Ltd., trade name LA-62, molecular weight = approx. 900), 2,2,6,6-tetramethyl-4-piperidyl/tridecyl-1,2,3,4-butanecarboxylate (manufactured by ADEKA Co., Ltd., trade name LA-67, molecular weight = approximately 900), Bis (2,2,6,6-tetramethyl-4-piperidyl) sepacate (manufactured by BASF Japan Co., Ltd., Tinuvin (registered trademark) 770, molecular weight = 480.7).

<Weather stabilizer (E)>
The pigments (F) used in the present invention are carbon black (F-1), titanium oxide (F-2), and a green pigment or a blue pigment (F-3).

The type of carbon black (F-1) is not particularly limited, and various known carbon blacks can be used. Carbon black (F-1) is available as a commercial product. The average particle size is also not limited, but the average primary particle size is preferably 10 to 40 nm.

The type and average particle size of titanium oxide (F-2) are not particularly limited, and various known titanium oxides can be used. Titanium oxide (F-2) is available as a commercial product.

The type of green pigment or blue pigment (F-3) is not particularly limited, and various known green pigments or various blue pigments can be used. Preferred specific examples include phthalocyanine pigments. The green pigment or blue pigment (F-3) is available as a commercial product. Preferred commercially available products are, for example, a blue pigment (manufactured by Clariant, trade name PV Fast Blue A4R) and a green pigment (manufactured by Heubach, trade name Vynamon Green 600734).

<Fatty acid metal salt (G)>
The type of fatty acid metal salt (G) used in the present invention is not particularly limited, and various known fatty acid metal salts can be used. Specific examples include magnesium stearate, calcium stearate, and zinc stearate. Fatty acid metal salt (G) is available as a commercial product.

Other additives such as nucleating agents, heat stabilizers, antistatic agents, antiaging agents, softeners, dispersants, and lubricants may be added to the polypropylene resin composition as necessary without impairing the purpose of the present invention. It can be blended within a range. The order of mixing the additives is arbitrary; they may be mixed at the same time, or a multi-step mixing method may be used, such as mixing some components and then mixing other components.

<Filler-containing polypropylene resin composition>
The filler-containing polypropylene resin composition of the present invention is a composition containing each of the components (A) to (G) described above and other optional components as necessary. The amounts of each component described below are based on the total amount of components (A) to (C) being 100 parts by mass.

The amount of the propylene polymer (A) is 60 to 75 parts by weight, preferably 65 to 75 parts by weight.

The amount of the ethylene/α-olefin copolymer (B) is 0 to 5 parts by weight, preferably 0 to 4 parts by weight.

The amount of inorganic filler (C) is 25 to 35 parts by weight, preferably 30 to 35 parts by weight.

The amount of the hindered phenolic antioxidant (D-1) having a molecular weight of 1000 or more is 0.01 to 1.0 parts by mass, preferably 0.1 to 0.2 parts by mass. The amount of the hindered phenolic antioxidant (D-2) having a molecular weight of less than 1000 is 0.01 to 1.0 parts by weight, preferably 0.1 to 0.2 parts by weight.

The amount of the benzoate light stabilizer (E-1) having a molecular weight of less than 1000 is 0.01 to 0.5 part by weight, preferably 0.05 to 0.2 part by weight. The amount of the hindered amine light stabilizer (E-2) having a molecular weight of less than 1000 is 0.01 to 0.5 part by weight, preferably 0.05 to 0.2 part by weight.

The amount of carbon black (F-1) is 0.4 to 1.0 parts by weight, preferably 0.5 to 0.9 parts by weight. The amount of titanium oxide (F-2) is 0.5 parts by mass or less, preferably 0.1 to 0.3 parts by mass. The amount of the green pigment or blue pigment (F-3) is 0.05 to 0.5 parts by weight, preferably 0.1 to 0.4 parts by weight.

The amount of fatty acid metal salt (G) is 0.01 to 1.0 parts by weight, preferably 0.1 to 0.5 parts by weight.

The filler-containing polypropylene resin composition of the present invention can be produced by blending the above-mentioned components (A) to (G) and other optional components as necessary. Each component may be blended sequentially in any order, or may be mixed simultaneously. Alternatively, a multi-step mixing method may be adopted in which some components are mixed and then other components are mixed. As a method for blending each component, for example, a method of mixing or melt-kneading each component simultaneously or sequentially using a mixing device such as a Banbury mixer, single screw extruder, twin screw extruder, high speed twin screw extruder, etc. Can be mentioned.

The melt flow rate (230° C., 2.16 kg load) of the filler-containing polypropylene resin composition of the present invention is preferably 5 to 100 g/10 minutes, more preferably 5 to 50 g/10 minutes.

The method for molding the filler-containing polypropylene resin composition of the present invention is not particularly limited, and various known methods can be used as methods for molding the resin composition. Injection molding is particularly preferred. The filler-containing polypropylene resin composition of the present invention can be suitably used in various fields such as automobile exterior parts, household goods, and home appliance parts. Particularly suitable are automobile exterior parts formed by injection molding this resin composition. Specific examples of automobile exterior parts include bumpers, side moldings, back doors, fenders, and back panels.

Hereinafter, the present invention will be explained in more detail based on Examples. However, the present invention is not limited to these.

Measurement and evaluation of physical properties in Examples and Comparative Examples were performed by the following methods.

[Melt flow rate (MFR) (g/10 min)]
Measurement was carried out in accordance with ISO 1133 under the conditions of a test load of 2.16 kg and a test temperature of 230°C.

[Intrinsic viscosity [η]]
Approximately 20 mg of the sample was dissolved in 15 ml of decalin, and the specific viscosity η _sp was measured in an oil bath at 135°C. This decalin solution was diluted by adding 5 ml of decalin solvent, and then the specific viscosity η _sp was measured in the same manner. This dilution operation was repeated two more times, and the value of η _sp /C when the concentration (C) was extrapolated to 0 was determined as the intrinsic viscosity [η].
[η]=lim(η _sp /C) (C→0)

[Amount of decane soluble portion (D _sol ) and insoluble portion amount (D _insol ) (mass%)]
In a glass measuring container, approximately 3 g of the sample [component (A)] (measured to the nearest 10 ^-4 g. This mass was expressed as x ₂ (g) in the formula below), 500 ml of n-decane, A small amount of a heat-resistant stabilizer soluble in n-decane was charged, and the temperature was raised to 150°C for 2 hours while stirring with a stirrer under a nitrogen atmosphere to dissolve the sample. After holding at 150°C for 2 hours, It was slowly cooled to 23°C over 8 hours. The obtained precipitate-containing liquid was filtered under reduced pressure using a 25G-4 standard glass filter manufactured by Iwata Glass Co., Ltd. 100 ml of the filtrate was collected and dried under reduced pressure to obtain a portion of the decane soluble component, and its mass was measured to the nearest 10 ^-4 g (this mass was expressed as x ₁ (g) in the formula below). did). Using these measured values, the amount of decane soluble portion (D _sol ) and the amount of insoluble portion (D _insol ) at room temperature (ie, 23° C.) were determined by the following formula.
D _sol (mass%) = 100×(500×x ₁ )/(100×x ₂ )
D _insol (mass%) = 100-D _sol

[Bending elastic modulus (MPa)]
Measurement was performed under the following conditions in accordance with ASTM D790.
Temperature: 23℃
Test piece: 127mm (length) x 12.7mm (width) x 6.35mm (thickness)
Bending speed: 30mm/min
Between spans: 100cm

[Load deflection temperature (℃)]
Measurement was performed under the following conditions in accordance with ASTM D648.
Test piece: 127mm (length) x 12.7mm (width) x 6.35mm (thickness)
How to place the test piece: Edgewise Bending stress: 0.45MPa

[Izod impact strength (J/m)]
Measurement was performed under the following conditions in accordance with ASTM D256.
Test piece: 63.5mm (length) x 12.7mm (width) x 3.2mm (thickness) with notch Test temperature: -30°C

[Weather resistance test (SWOM)]
The color difference (ΔE) was measured under the following conditions to confirm the presence or absence of cracks.
Light source: Sunshine carb arc BPT: 83℃
Rainfall conditions: 12/60 minutes Irradiation time: 2000hr
Test piece: 60mm (length) x 40mm (width) x 3mm (thickness)
Color difference: Calculate the ΔE of the sample before weather resistance test and after 2000 hours of weather resistance test Color difference was confirmed using a color difference meter under the following conditions Reflection method, SCI, light source: C/2
Appearance: Check for cracks using a microscope

[Heat resistance test]
A heat resistance test was conducted under the following conditions.
Test piece (1): 63.5 mm (length) x 12.7 mm (width) x 3.2 mm (thickness) with notch Test piece (2): 60 mm (length) x 40 mm (width) x 3 mm (thickness)
Testing machine: Gear oven Testing temperature: 120℃
Test time: 2000hr

(1) Impact strength retention rate after heat resistance test (%)
The Izod impact strength of the test piece (1) after the heat resistance test was measured by the method described above, and the impact strength retention rate (%) was calculated by dividing by the Izod impact strength before the heat resistance test and multiplying by 100. .
(2) Appearance after heat resistance test The presence or absence of cracks in the test piece (2) after the heat resistance test was confirmed using a microscope.

[Color tone]
The color tone was measured according to JIS Z 8722 under the following conditions, and the L value, a value, and b value were calculated according to JIS Z 8781.
Test piece: 90mm (length) x 50mm (width) x 2mm (thickness)
Light source: D65
Field of view: 10°
Specular reflection light processing: SCI

Note that when the L value, a value, and b value of the composition are within the following ranges, the jet blackness tends to be excellent, so these are set as the target values in this test.
L value: <27
a value: -1 to 0
b value: -1.5 to 0.5

In the Examples and Comparative Examples, the propylene block copolymer obtained in Production Example 1 below was used as component (A).

<Manufacture example 1>
(1) Preparation of solid titanium catalyst component 95.2 g of anhydrous magnesium chloride, 442 ml of decane, and 390.6 g of 2-ethylhexyl alcohol were heated at 130°C for 2 hours to form a homogeneous solution. 0.3 g was added thereto, and the mixture was further stirred and mixed at 130° C. for 1 hour to dissolve phthalic anhydride.

After cooling this homogeneous solution to room temperature, 75 ml of the homogeneous solution was added dropwise over 1 hour to 200 ml of titanium tetrachloride maintained at -20°C. After the charging was completed, the temperature of this liquid mixture was raised to 110°C over 4 hours, and when it reached 110°C, 5.22g of diisobutyl phthalate (DIBP) was added and kept stirring at the same temperature for 2 hours. .

After the 2-hour reaction was completed, a solid portion was collected by hot filtration, and this solid portion was resuspended in 275 mL of titanium tetrachloride, and then heated again at 110° C. for 2 hours. After the reaction was completed, the solid portion was again collected by hot filtration and thoroughly washed with decane and hexane at 110° C. until no free titanium compound was detected in the solution.

Detection of this free titanium compound was confirmed by the following method. 10 mL of the supernatant liquid of the solid catalyst component was collected with a syringe and charged into a 100 mL branched Schlenk that had been purged with nitrogen in advance. Next, the hexane solvent was dried in a nitrogen stream, and the product was further vacuum dried for 30 minutes. 40 mL of ion-exchanged water and 10 mL of (1+1) sulfuric acid were added to this and stirred for 30 minutes. This aqueous solution was transferred to a 100 mL volumetric flask through filter paper, and then 1 mL of concentrated H ₃ PO ₄ solution was added as a masking agent for iron (II) ions and 5 mL of 3% H ₂ O ₂ was added as a coloring reagent for titanium, and further added with ion-exchanged water. This volumetric flask, which had been made up to 100 mL, was shaken, and after 20 minutes, absorbance at 420 nm was observed using UV light, and free titanium was washed and removed until this absorption was no longer observed.

The solid titanium catalyst component prepared as described above was stored as a decane slurry, and a portion of this was dried for the purpose of investigating the catalyst composition. The composition of the solid titanium catalyst component thus obtained was 2.3% by weight of titanium, 61% by weight of chlorine, 19% by weight of magnesium, and 12.5% by weight of DIBP.

(2) Production of prepolymerization catalyst 100 g of the solid titanium catalyst component, 39.3 mL of triethylaluminum, and 100 L of heptane were placed in a 200 L autoclave equipped with a stirrer, and the internal temperature was maintained at 15 to 20°C, and 600 g of propylene was inserted. The reaction was allowed to proceed with stirring for 70 minutes.

(3) Main polymerization In a jacketed circulating tubular polymerization vessel with an internal capacity of 58 L, propylene was supplied at 43 kg/hour, hydrogen was supplied at 123 NL/hour, and the catalyst slurry produced in (2) above was added as a solid titanium catalyst component to 0.56 g/hour. Triethylaluminum (1.9 mL/hour) and dicyclopentyldimethoxysilane (3.7 mL/hour) were continuously fed, and polymerization was carried out in a full liquid state without the presence of a gas phase. The temperature of the tubular polymerization vessel was 69°C, and the pressure was 3.5 MPa/G.

The obtained slurry was sent to a vessel polymerization vessel with an internal capacity of 100 L equipped with a stirrer for further polymerization. Propylene was supplied to the polymerization vessel at a rate of 45 kg/hour and hydrogen was supplied such that the hydrogen concentration in the gas phase was 10.8 mol %, and polymerization was carried out at a polymerization temperature of 68° C. and a pressure of 3.2 MPa/G.

Next, the obtained slurry was transferred to a liquid transfer tube with an internal capacity of 2.4 L, and this slurry was gasified to perform gas-solid separation. Thereafter, the polypropylene homopolymer powder was sent to a gas phase polymerization vessel having an internal capacity of 480 L, and ethylene/propylene block copolymerization was performed. Propylene, ethylene, and hydrogen were continuously added so that the gas composition in the gas phase polymerization vessel was ethylene/(ethylene + propylene) = 0.44 (mole ratio) and hydrogen/ethylene = 0.12 (mole ratio). and polymerization was carried out at a polymerization temperature of 70° C. and a pressure of 0.6 MPa/G.

Next, the obtained propylene block copolymer was vacuum dried at 80°C. The MFR (230°C, 2.16 kg load) of this propylene/ethylene block copolymer (A-1) is 14 g/10 minutes, and the amount of decane soluble portion (ethylene/propylene copolymer portion (A2)) was 12% by mass, the ethylene content of the decane soluble portion was 47 mol%, and the intrinsic viscosity [η] of the decane soluble portion was 2.8 dl/g.

In the examples and comparative examples, the following compounds were used as components (B) to (G).

<Ethylene/α-olefin copolymer (B)>
Ethylene/1-butene random copolymer (manufactured by Mitsui Chemicals, Inc., TAFMER (registered trademark) A1050S, ethylene content = 83 mol%, MFR (230°C, 2.16 kg load) = 2 g/10 min, density = 0. 862g/ ^cm3 )

<Inorganic filler (C)>
Talc (manufactured by Hayashi Kasei Co., Ltd., trade name GHL-7. Average particle size 5.8 μm)

<Antioxidant (D)>
"D-1": Hindered phenolic antioxidant with a molecular weight of 1000 or more (pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate, manufactured by BASF Japan Co., Ltd., Irganox (registered trademark) 1010, molecular weight = 1177.7)
"D-2": Hindered phenolic antioxidant (D-2) with a molecular weight of less than 1000 (tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate, manufactured by BASF Japan Co., Ltd. , Irganox® 3114, molecular weight = 784.0)
"DP": Phosphorous antioxidant (manufactured by BASF Japan Co., Ltd., Irgafos (registered trademark) 168)
"DS": Sulfur-based antioxidant (manufactured by Mitsubishi Chemical Corporation, trade name DMTP "Yoshitomi")

<Weather stabilizer (E)>
"E-1": Benzoate light stabilizer with a molecular weight of less than 1000 (2,4-di-t-butylphenyl-3,5-di-t-butyl-4-hydroxybenzoate, manufactured by BASF Japan Co., Ltd., Tinuvin ( (registered trademark) 120, molecular weight = 438.7)
"E-2": Hindered amine light stabilizer with molecular weight less than 1000 (tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, ADEKA Co., Ltd. (product name: LA-52, molecular weight = 847.2)

<Pigment (F)>
"F-1": Carbon black (manufactured by Orion Engineered Carbons, trade name HIBLACK 890B, average primary particle diameter = 15 nm)
"F-2": Titanium oxide (manufactured by Chemours, trade name Ti-Pure R-104)
"F-3": In Examples 1 to 4 and Comparative Examples 2 to 5, 0.05 parts by weight of a blue pigment (manufactured by Clariant, trade name PV Fast Blue A4R) and a green pigment (manufactured by Heubach, trade name) Vynamon Green 600734) was used in combination at 0.15 parts by weight.

<Fatty acid metal salt (G)>
Fatty acid metal salt (manufactured by NOF Corporation, trade name Magnesium Stearate G)

<Examples 1 to 4, Comparative Examples 1 to 5>
Each component (A) to (G) was mixed in the amounts (parts by mass) shown in Table 1, and the mixture was heated at a cylinder temperature of 180°C using a twin-screw extruder (TEX (registered trademark) 30α, manufactured by Japan Steel Works, Ltd.). A filler-containing polypropylene resin composition was obtained by extrusion under conditions of a screw rotation of 750 rpm and an extrusion rate of 60 kg/h.

Table 2 shows the physical properties of the injection molded article (test piece) produced from the obtained filler-containing polypropylene resin composition.

As is clear from the results shown in Tables 1 and 2, in Examples 1 to 4, rigidity and Izod impact strength at low temperatures (-30°C) were exhibited in a very well-balanced manner. Moreover, the deflection temperature under load was also very high. Therefore, it is also effective in maintaining rigidity at high temperatures. Furthermore, the L value, a value, and b value met the target values described earlier, and a good jet blackness with a luxurious feel was expressed. In addition, the impact strength retention rate after weather resistance (SWOM) and heat resistance tests was high, and no cracks were generated.

In Comparative Example 1, since no green pigment or blue pigment (F-3) was blended, the L value, a value, and b value did not meet the target values, and jet blackness was not developed.

In Comparative Example 2, the blended amount of the inorganic filler (C) was too small, so the flexural modulus and Izod impact strength were poor, and the physical property balance was poor. In addition, the deflection temperature under load was low, and it was inferior in terms of maintaining rigidity at high temperatures.

In Comparative Example 3, the amount of inorganic filler (C) blended is too large, so even if green pigment or blue pigment (F-3) is blended, the L value does not reach the target value, and good jet blackness is not achieved. It did not occur.

In Comparative Example 4, a sulfur-based antioxidant (DS), which is generally excellent in improving heat resistance at high temperatures, was blended, but cracks occurred in the heat resistance test.

In Comparative Example 5, a phosphorus antioxidant (DP) was blended, but cracks occurred during the heat resistance test, and the impact strength retention rate after the heat resistance test was low.

As is clear from the above results, since the filler-containing polypropylene resin composition of the present invention has a specific composition, it has excellent physical properties such as rigidity, impact resistance, and heat resistance. In addition, a specific amount of inorganic filler (C) and a specific amount of three types of pigments (F-1), (F-2) and (F-3) [especially pigment (F-3)] are combined. This results in a high quality jet black finish.

The filler-containing polypropylene resin composition of the present invention is useful as a molded material in various fields such as automobile exterior parts such as bumpers, side moldings, back doors, fenders, and back panels, household goods, and home appliance parts. In particular, it can be suitably used for automobile exterior parts.

Claims (3)

70 to 100% by mass of the propylene homopolymer part (A1) and 0 to 30% by mass of the ethylene-propylene copolymer part (A2) having an intrinsic viscosity [η] of 2.0 to 8.0 dl/g (components 60 to 75 parts by mass of a propylene polymer (A) consisting of (A1) and component (A2) (total of 100% by mass);
0 to 5 parts by mass of ethylene/α-olefin copolymer (B) (α-olefin has 3 to 10 carbon atoms),
Inorganic filler (C) (excluding titanium oxide) 25 to 35 parts by mass,
As the antioxidant (D), 0.01 to 1.0 parts by mass of a hindered phenolic antioxidant (D-1) with a molecular weight of 1000 or more and a hindered phenolic antioxidant (D-2) with a molecular weight of less than 1000. ) 0.01 to 1.0 parts by mass,
As the weathering stabilizer (E), 0.01 to 0.5 parts by mass of a benzoate light stabilizer (E-1) with a molecular weight of less than 1,000 and 0.0 parts by mass of a hindered amine light stabilizer (E-2) with a molecular weight of less than 1,000. 01 to 0.5 parts by mass,
As the pigment (F), 0.4 to 1.0 parts by mass of carbon black (F-1), 0.1 to 0.5 parts by mass of titanium oxide (F-2), and a green pigment or a blue pigment ( F-3) 0.05 to 0.5 parts by mass,
as well as,
Fatty acid metal salt (G) 0.01 to 1.0 parts by mass [However, the total amount of component (A), component (B) and component (C) is 100 parts by mass. ]
A filler-containing polypropylene resin composition comprising:
The antioxidant (D-1) includes pentaerythritol-tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate,
A filler-containing polypropylene resin composition containing tris-(3,5-di-t-butyl-4-hydroxybenzyl)-isocyanurate as the antioxidant (D-2). The filler-containing polypropylene resin composition according to claim 1, wherein the propylene polymer (A) is a propylene/ethylene block copolymer. An automobile exterior part obtained by injection molding the filler-containing polypropylene resin composition according to claim 1 or 2.