JP5827143B2 - Polypropylene resin composition for automotive exterior members and automotive exterior members - Google Patents

Description

  The present invention relates to a polypropylene resin composition for an automotive exterior member and an automotive exterior member using the same, and more specifically, moldability (high fluidity), dimensional stability (low linear expansion coefficient), physical property balance (high rigidity). The present invention relates to a polypropylene resin composition for an automotive exterior member and an automotive exterior member that are excellent in high impact strength and that can provide good coating appearance quality.

Polypropylene resin compositions are excellent as various molded products in the field of industrial parts, for example, door trims, instrument panels, bumpers, side moldings, back doors, fenders and other automotive parts, televisions and other household appliance parts. It has been put into practical use by taking advantage of its formability, mechanical strength, environmental adaptability and economic characteristics. On the other hand, since polypropylene has high crystallinity, it is known that the dimensional change (linear expansion coefficient) with respect to temperature is large. Due to this property, alignment of parts is required in automobile parts using polypropylene resin compositions. There were problems such as gaps in the eyes and deterioration in the ease of installation when assembling the parts.
In particular, molded articles such as automobile exterior members are becoming larger and more complicated in design, and accordingly, a high balance of physical properties (high rigidity and impact strength) is exhibited in polypropylene resin compositions and molded articles. In addition, it is required to satisfy both high dimensional stability, high moldability (high fluidity), and improved appearance that further enhances the product value.

Low linear expansion is achieved by a resin composition comprising a polypropylene resin polymerized using a metallocene catalyst and carbon fiber for the purpose of improving the dimensional stability (low linear expansion coefficient) and appearance of the polypropylene resin composition. The thing which aims at the improvement of a coefficient and the coating external appearance quality is proposed (for example, refer patent document 1).
However, since the resin composition uses fibers as fillers, it cannot be said that the mechanical properties or the physical property balance is sufficient.

In addition to improving dimensional stability (low linear expansion coefficient) and physical property balance (high rigidity and high impact strength), whisker-like fillers are used as fillers for the purpose of improving molding appearance, and specific MFR ( A resin composition comprising a propylene / ethylene block copolymer having a melt flow rate) has been proposed (see, for example, Patent Document 2).
However, the resin composition was not sufficient for the linear expansion coefficient.

  Under such circumstances, high moldability (high fluidity) is a performance necessary for solving the problems of conventional polypropylene resin compositions and obtaining automotive exterior parts such as bumpers, side moldings, back doors, and fenders. ), A polypropylene-based resin composition that has excellent dimensional stability (low linear expansion coefficient) and high physical property balance (high rigidity, high impact strength) as well as excellent coating appearance quality.

JP 2009-149823 A JP 2010-077396 A

  In view of the above-mentioned problems of the prior art, the object of the present invention is excellent in moldability (high fluidity), dimensional stability (low linear expansion coefficient), physical property balance (high rigidity, high impact strength) and good coating. An object of the present invention is to provide a polypropylene-based resin composition for automobile exterior members and an automobile exterior member that can provide appearance quality.

  As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention have developed a specific polypropylene resin (component (1)) polymerized using a Ziegler catalyst, a specific ethylene / α-olefin copolymer. (Component (2)) and a specific shape of talc (component (3)) each containing a specific amount of a polypropylene resin composition for automobile exterior members has moldability (high fluidity) and dimensional stability (low linear expansion) Coefficient) and physical property balance (high rigidity, high impact strength), and found that good coating appearance quality can be obtained, and the present invention has been completed.

That is, according to the first invention of the present invention, the following components (1) to (3) are contained in an amount of 35 to 50% by weight of component (1) based on the total amount of components (1) to (3). Provided is a polypropylene resin composition for an automotive exterior member, wherein (B) is contained in a proportion of 15 to 25% by weight and component (C) is contained in a proportion of 35 to 40% by weight.
Component (1) Polypropylene resin having a melt flow rate (230 ° C., 2.16 kg load) of 100 to 110 g / 10 min and a melting peak temperature of 160 to 165 ° C. and polymerized using a Ziegler catalyst Component (2) Melt Ethylene / α-olefin copolymer having a flow rate (230 ° C., 2.16 kg load) of 2 to 30 g / 10 min Component (3) Talc having an aspect ratio of 15 to 17 and an average particle diameter of 6 to 8 μm

  According to the second invention of the present invention, in the first invention, the component (1) is a crystalline propylene polymer portion having a melt flow rate (230 ° C., 2.16 kg load) of 190 g / 10 min or more. And a propylene / ethylene block copolymer comprising an ethylene / propylene copolymer portion. 2. A polypropylene resin composition for an automotive exterior member according to claim 1.

  According to the third invention of the present invention, in the second invention, the proportion of the ethylene / propylene copolymer portion is 10 to 20% by weight based on the entire propylene / ethylene block copolymer. A polypropylene resin composition for automobile exterior members is provided.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the following characteristics (1) to (4) are satisfied: Things are provided.
Characteristics (1) Melt flow rate (according to ASTM-D1238, 230 ° C., 2.16 kg load) is 30 to 40 g / 10 min. Characteristics (2) Flexural modulus (according to ASTM-D790, 23 ° C.) is 2500 to 3500 MPa.
Characteristic (3) Izod impact strength (according to ASTM-D785, 23 ° C.) is 200 to 350 J / m
Characteristic (4) Linear expansion coefficient (based on JIS K7197) is 4 × 10 ⁻⁵ / ° C. or less

  According to a fifth aspect of the present invention, there is provided an automotive exterior member obtained by injection molding the polypropylene resin composition for an automotive exterior member according to any one of the first to fourth aspects. Provided.

  According to a sixth aspect of the present invention, there is provided an automobile exterior member characterized in that, in the fifth aspect, the average value of web scan on the coating surface is 30 or less.

  According to the present invention, high moldability (high fluidity), dimensional stability (low coefficient of linear expansion) and physical properties, which are performances required for obtaining automobile exterior parts such as bumpers, side moldings, back doors, and fenders. It is possible to obtain a polypropylene-based resin composition that is excellent in paint appearance quality as well as in balance (high rigidity and high impact strength).

FIG. 1 is a schematic view showing an example of an apparatus for producing the component (1) of the present invention.

The present invention provides an automotive exterior member containing a specific amount of component (1): a specific polypropylene resin, component (2): a specific ethylene / α-olefin copolymer, and component (3): a specific shape of talc. A polypropylene resin composition for automobiles and an automobile exterior member using the same.
Hereinafter, each component, such as a component of a polypropylene resin composition, this resin composition, its manufacture and shaping | molding, a member, is demonstrated in detail.

[I] Components of polypropylene resin composition for automobile exterior members Component (1): Polypropylene resin The polypropylene resin of component (1) used in the polypropylene resin composition for automobile exterior members of the present invention (hereinafter also referred to as “polypropylene resin composition”) is a melt flow rate. (230 ° C., 2.16 kg load, also referred to as MFR) is 100 to 110 g / 10 min, melting peak temperature is 160 to 165 ° C., and it is necessary to be a polypropylene resin polymerized using a Ziegler catalyst. .
Examples of the polypropylene resin include propylene / ethylene random copolymer resin and propylene / ethylene block copolymer resin. In order to obtain a high mechanical property balance, a crystalline propylene polymer portion, ethylene / propylene A propylene / ethylene block copolymer comprising a copolymer portion is preferred.
Hereinafter, the production method of component (1) will be described with reference to production examples of the propylene / ethylene block copolymer.

(1) Production method (a) Preparation of solid catalyst component A 10 L autoclave equipped with a stirrer was sufficiently replaced with nitrogen, and 2 L of purified toluene was introduced. To this, 200 g of Mg (OEt) ₂ and 1 L of TiCl ₄ were added at room temperature. The temperature was raised to 90 ° C. and 50 ml of di-n-butyl phthalate was introduced. Thereafter, the temperature was raised to 110 ° C. to carry out a reaction for 3 hours. The reaction product was thoroughly washed with purified toluene. Next, purified toluene was introduced to adjust the total liquid volume to 2 L. 1 L of TiCl ₄ was added at room temperature, the temperature was raised to 110 ° C., and the reaction was performed for 2 hours. The reaction product was thoroughly washed with purified toluene. Subsequently, the refined toluene was introduce | transduced and the whole liquid quantity was adjusted to 2L.
1 L of TiCl ₄ was added at room temperature, the temperature was raised to 110 ° C., and the reaction was performed for 2 hours. The reaction product was thoroughly washed with purified toluene. Furthermore, using purified n-heptane, toluene was replaced with n-heptane to obtain a solid component slurry. A portion of this slurry was sampled and dried. As a result of analysis, the Ti content of the solid catalyst component was 2.7% by weight.
Next, a 20 L autoclave equipped with a stirrer was sufficiently replaced with nitrogen, and 100 g of the solid component slurry was introduced as a solid component. Purified n-heptane was introduced to adjust the solid component concentration to 25 g / L. 50 ml of SiCl ₄ was added and a reaction was performed at 90 ° C. for 1 hr. The reaction product was thoroughly washed with purified n-heptane.
Thereafter, purified n-heptane was introduced to adjust the liquid level to 4 L. To this, 30 ml of dimethyldivinylsilane, 30 ml of diisopropyldimethoxysilane, and 80 g of triethylaluminum diluted n-heptane as triethylaluminum were added and reacted at 40 ° C. for 2 hours. The reaction product was thoroughly washed with purified n-heptane, and a portion of the resulting slurry was sampled and dried. As a result of analysis, the solid catalyst component contained 1.2% by weight of Ti and 8.8% by weight of diisopropyldimethosisilane.

Using the solid catalyst component obtained above, prepolymerization was performed by the following procedure. Purified n-heptane was introduced into the slurry, and the concentration of the solid catalyst component was adjusted to 20 g / L.
After the slurry was cooled to 10 ° C., 10 g of a triethylaluminum diluted n-heptane solution was added as triethylaluminum, and 280 g of propylene was supplied over 4 hours.
After the supply of propylene was completed, the reaction was further continued for 30 minutes. Next, the gas phase was sufficiently replaced with nitrogen, and the reaction product was thoroughly washed with purified n-heptane. The obtained slurry was extracted from the autoclave and vacuum dried to obtain a solid catalyst component. This solid catalyst component contained 2.5 g of polypropylene per 1 g of the solid catalyst component. As a result of analysis, the portion of the solid catalyst component excluding polypropylene contained 1.0% by weight of Ti, 17.5% by weight of Mg, and 8.2% by weight of diisopropyldimethosisilane.

(A) Polymerization The polymerization method will be described with reference to the flow sheet shown in FIG. In the horizontal polymerization vessel 10 (L / D = 3.7, internal volume 100 liters) 10 of the first polymerization step having a stirring blade, 0.31 g / hr of the above-mentioned prepolymerized solid catalyst component and triethylaluminum as the organic aluminum compound were added. It supplied continuously so that Al / Mg molar ratio might be set to 5 with respect to Mg in a solid catalyst component. While maintaining the conditions of a reaction temperature of 70 ° C., a reaction pressure of 2.2 MPa, and a stirring speed of 35 rpm, hydrogen gas was added so that the hydrogen concentration in the gas phase in the polymerization vessel 10 was maintained at a hydrogen / propylene molar ratio of 0.10. The MFR of the first stage polymer was adjusted by continuously supplying from the circulation pipe 4.
The reaction heat was removed by the vaporization heat of the raw material liquefied propylene supplied from the pipe 17. The unreacted gas discharged from the polymerization vessel 10 was cooled and condensed outside the reactor system through the pipe 13 and refluxed to the polymerization vessel 10 through the pipe 17.
The produced first-stage polymerization polymer was continuously extracted from the polymerization vessel 10 through the pipe 32 so that the retained level of the polymer was 50% by volume of the reaction volume, and supplied to the polymerization vessel 20 in the second polymerization step. . At this time, a part of the polymer was intermittently collected from the pipe 32 and used as a sample for measuring the polymer yield per unit weight of MFR and catalyst. The polymer yield per catalyst unit weight was calculated from the Mg content in the polymer measured by inductively coupled plasma emission spectroscopy (ICP method) (first polymerization step).

A propylene polymer from the first stage polymerization tank and an ethylene-propylene mixed gas are continuously supplied from a first stage polymerization tank and a pipe 6 to a horizontal polymerization vessel 20 (L / D = 3.7, internal volume 100 liters) having a stirring blade, Copolymerization of ethylene and propylene was performed. The reaction conditions are agitation speed of 25 rpm, temperature of 60 ° C., pressure of 2.0 MPa, in order to adjust the ethylene content in the ethylene / propylene copolymer and the molecular weight of the ethylene / propylene copolymer, The composition was adjusted to an ethylene / propylene molar ratio of 0.35 and a hydrogen / ethylene molar ratio of 0.12. Oxygen was supplied from the pipe 7 as a polymerization activity inhibitor for adjusting the polymerization amount of the propylene-ethylene copolymer.
The reaction heat was removed by the heat of vaporization of the raw material liquefied propylene supplied from the pipe 27. The unreacted gas discharged from the polymerization vessel 20 was cooled and condensed outside the reactor system through the pipe 23 and refluxed to the polymerization vessel 20. The propylene / ethylene block copolymer produced in the polymerization step was continuously withdrawn from the polymerization vessel 20 through the pipe 39 so that the retained level of the polymer was 50% by volume of the reaction volume. The production rate of the propylene / ethylene block copolymer was 11.2 / hr (second polymerization step).

(2) Physical properties The total MFR (230 ° C., 2.16 kg load) of component (1) needs to be 100 to 110 g / 10 minutes. If the MFR is less than 100 g / 10 min, the dimensional stability (linear expansion coefficient), moldability (high fluidity), and (paint appearance quality) of the polypropylene resin composition and the molded product thereof may be deteriorated. . On the other hand, if the MFR is larger than 110 g / 10 min, mechanical properties may be deteriorated.
Moreover, in this specification, MFR is the value measured by 230 degreeC and a 2.16kg load based on ASTM-D1238.

The melting peak temperature of the entire component (1) needs to be 160 to 165 ° C. If the melting peak temperature is less than 160 ° C, the mechanical property balance may be deteriorated. On the other hand, when the melting peak temperature is 165 ° C. or higher, the mechanical property balance may be deteriorated.
In this specification, the melting peak temperature is the melting peak temperature (Tm) measured by the DSC method. For example, a sample piece formed into a sheet using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.). In a 5 mg aluminum pan, heated from 50 ° C. to 200 ° C. at a heating rate of 100 ° C./minute, held for 5 minutes, then cooled to 40 ° C. at 10 ° C./minute for crystallization and held for 1 minute. Thereafter, it is a value measured as the maximum melting peak temperature when the temperature is raised to 200 ° C. at 10 ° C./min.

  When component (1) is a propylene / ethylene block copolymer, the MFR (230 ° C., 2.16 kg load) of the crystalline propylene polymer portion of the copolymer is preferably 190 g / 10 min or more. . The upper limit is not particularly limited, but is preferably 220 g / 10 minutes, and particularly preferably 195 to 210 g / 10 minutes. If the MFR is less than 190 g / 10 minutes, the moldability (high fluidity) of the polypropylene-based resin composition and the molded product thereof, and further the coating appearance quality may be deteriorated. On the other hand, if the MFR is 220 g / 10 min or more, the mechanical property balance may be deteriorated.

  When component (1) is a propylene / ethylene block copolymer, the ethylene content of the ethylene / propylene copolymer portion of the copolymer is preferably 40 to 50% by weight. When the ethylene content is less than 40% by weight and more than 50% by weight, the mechanical property balance tends to be lowered.

The ethylene / propylene copolymer part amount (ratio) and the ethylene content of the ethylene / propylene copolymer part can be quantified by the following method.
(A) Analytical device to be used (a-1) Cross sorter CFC T-100 (abbreviated as CFC) manufactured by Dia Instruments Co., Ltd.
(A-2) 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.
(A-3) 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 (b-1) Solvent: orthodichlorobenzene (ODCB)
(B-2) Sample concentration: 4 mg / ml
(B-3) Injection amount: 0.4 ml
(B-4) Crystallization: The temperature is lowered from 140 ° C. to 40 ° C. over about 40 minutes.
(B-5) 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. In addition, the elution ratio (unit:% by 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), respectively W ₄₀ , W ₁₀₀ , and W ₁₄₀ are defined. W ₄₀ + W ₁₀₀ + W ₁₄₀ = 100. Moreover, each fractionated fraction is automatically transported to the FT-IR analyzer as it is.
(B-6) 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. .
(C-1) Detector: MCT
(C-2) Resolution: 8 cm ⁻¹
(C-3) Measurement interval: 0.2 minutes (12 seconds)
(C-4) 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 × M ^α ) used at that time.
(D-1) At the time of creating a calibration curve using standard polystyrene K = 0.000138, α = 0.70
(D-2) Component (A) During measurement of sample of propylene / ethylene block copolymer K = 0.000103, 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) Ratio of ethylene / propylene copolymer portion (Wc)
The ratio (Wc) of the ethylene / propylene copolymer portion in the component (A) propylene / ethylene block copolymer in the present invention is theoretically defined by the following formula (I), and is determined by the following procedure. .
Wc (% by weight) = W ₄₀ × A ₄₀ / B ₄₀ + W ₁₀₀ × A ₁₀₀ / B ₁₀₀ (I)
In the formula (I), W ₄₀ and W ₁₀₀ are elution ratios (unit:% by weight) in each of the above-described fractions, and A ₄₀ and A ₁₀₀ are actual values in the respective fractions corresponding to W ₄₀ and W _100. It is the average ethylene content (unit: wt%) of measurement, and B ₄₀ and B ₁₀₀ are the ethylene content (unit: wt%) of the ethylene / propylene copolymer portion contained in each fraction.
A method for _obtaining A ₄₀ , A ₁₀₀ , B ₄₀ , and B ₁₀₀ 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 ethylene / propylene copolymer portion contained in fraction 1 (portion soluble at 40 ° C.). When fraction 1 contains only an ethylene / propylene copolymer portion and no propylene polymer, W ₄₀ contributes to the ethylene / propylene copolymer portion content derived from fraction 1 as it is in the whole. In addition to fractions derived from ethylene / propylene copolymer, fraction 1 also contains a small amount of components derived from propylene polymer (extremely low molecular weight components and atactic polypropylene), so that part must be corrected. . Therefore, by multiplying W ₄₀ by A ₄₀ / B ₄₀ , the amount derived from the ethylene / propylene copolymer in fraction 1 is calculated. For example, when the average ethylene content (A ₄₀ ) of fraction 1 is 30% by weight and the ethylene content (B ₄₀ ) of the ethylene / propylene copolymer contained in fraction 1 is 40% by weight, 30/40 = 3/4 (that is, 75% by weight) is derived from an ethylene / propylene copolymer, and 1/4 is derived from a propylene polymer. Thus, the operation of multiplying A ₄₀ / B ₄₀ by the first term on the right side means that the contribution of the ethylene / propylene copolymer is calculated from the weight% (W ₄₀ ) of the fraction 1. The same applies to the second term on the right side, and for each fraction, the ethylene / propylene copolymer partial content is obtained by calculating and adding the contribution of the ethylene / propylene copolymer.

(E-1) As described above, the average ethylene contents corresponding to fractions 1 and 2 obtained by CFC measurement are A ₄₀ and A ₁₀₀ , respectively (unit is weight%). A method for obtaining the average ethylene content will be described later.

(E-2) The ethylene content corresponding to the peak position in the differential molecular weight distribution curve of fraction 1 is defined as B ₄₀ (unit is% by weight). Fraction 2 is considered to be substantially defined as B ₁₀₀ = 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. B ₄₀ and B ₁₀₀ are ethylene contents of the ethylene / propylene copolymer portion 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 fractionating the propylene polymer and the ethylene / propylene copolymer mixed in the fraction.
As a result of examination using various model samples, B ₄₀ can explain the improvement effect of material physical properties well by using the ethylene content corresponding to the peak position of the differential molecular weight distribution curve of fraction 1. all right. Further, B ₁₀₀ has crystallinity derived from ethylene chain, and the amount of ethylene / propylene copolymer contained in these fractions is relative to the amount of ethylene / propylene copolymer contained in fraction 1. For two reasons, the approximation to 100 is closer to the actual situation and causes almost no error in calculation. Therefore, the analysis is performed with B ₁₀₀ = 100.

(E-3) For the above reason, the ratio (Wc) of the ethylene / propylene copolymer portion is determined according to the following formula.
Wc _{(wt%) = W 40 × A 40} / B 40 + W 100 × A 100/100 ... (II)
That is, W ₄₀ × A ₄₀ / B ₄₀ which is the first term on the right side of the formula (II) indicates the content (% by weight) of ethylene / propylene copolymer having no crystallinity, and W ₁₀₀ × which is the second term. a _100/100 indicates the ethylene-propylene copolymer portion content with crystalline (wt%).
_Here, the average ethylene content _A 40 of _{B 40} and each of the fractions obtained by the CFC measurement 1 and _{2, A 100} is determined as follows.
Ethylene content corresponding to the peak position of the differential molecular weight distribution curve is B _40. 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 at the time of measurement, is the average ethylene content A _{40 of} fraction 1. The average ethylene content A _{100 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, only polymers having no crystallinity at 40 ° C. (for example, most of ethylene / propylene copolymer, or extremely low molecular weight component and atactic component in the propylene polymer portion) It has the meaning that it is a temperature condition necessary and sufficient for fractionation. 100 ° C. means a component that is insoluble at 40 ° C. but becomes soluble at 100 ° C. (for example, a component having crystallinity in the ethylene / propylene copolymer due to a chain of ethylene and / or propylene, and crystallinity) The temperature is necessary and sufficient to elute only the low propylene polymer). 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 propylene polymer and an extremely high molecular weight in an ethylene / propylene copolymer) This temperature is necessary and sufficient for eluting only the component having high ethylene crystallinity and recovering the entire amount of the propylene / ethylene block copolymer used for the analysis. W ₁₄₀ does not contain any ethylene / propylene copolymer component, or even if it is present, the amount is very small and can be substantially ignored, so the ratio of ethylene / propylene copolymer or ethylene / propylene copolymer Is excluded from the calculation of the ethylene content.

(F) Ethylene content of ethylene / propylene copolymer portion The ethylene content of the component (A) propylene / ethylene block copolymer of the ethylene / propylene copolymer portion in the present invention uses the value described above, It is obtained from the following formula.
Ethylene content (% by weight) of ethylene / propylene copolymer portion = (W ₄₀ × A ₄₀ + W ₁₀₀ × A ₁₀₀ ) / Wc
However, Wc is the ratio (% by weight) of the ethylene / propylene copolymer portion determined previously.

The intrinsic viscosity _{[eta] copoly} ethylene-propylene copolymer portion of the component (1) is preferably 7.0~12.0dl / g, more preferably 7.0~11.0dl / g, especially preferably 7 .1 to 10.0 dl / g. When the intrinsic viscosity [η] _copolymer is less than 7.0 dl / g, the dimensional stability and (coating appearance quality) of the polypropylene resin composition and the molded product thereof are liable to be lowered. Specifically, the linear expansion coefficient Tends to be high, (paint appearance quality) tends to be low, and if it exceeds 12.0 dl / g, impact strength tends to be low.

Incidentally, the intrinsic viscosity [eta] _copoly of the ethylene-propylene copolymer portion in component (A) a propylene-ethylene block copolymer in the present invention is determined as follows.
First, after the polymerization of the crystalline propylene polymer part is completed, a part is sampled from the polymerization tank, and the intrinsic viscosity [η] _{homo of the part} is measured. Next, after polymerizing the crystalline propylene polymer portion, the intrinsic viscosity [η] _F of the final polymer (F) obtained by polymerizing the ethylene / propylene copolymer portion is measured. This measurement is performed at a temperature of 135 ° C. using decalin as a solvent using an Ubbelohde viscometer. [Η] _copy is obtained from the following relationship.
[Η] _F = (100−Wc) / 100 × [η] _homo + Wc / 100 × [η] _copy

  The ratio of the component (1) of the ethylene / propylene copolymer portion to the entire block copolymer is preferably 10 to 20% by weight. When the proportion is less than 10% by weight, the linear expansion coefficient of the polypropylene resin composition and its molded product tends to be high, and when it exceeds 20% by weight, gel is likely to be generated and the coating appearance quality is likely to deteriorate. In addition, the mechanical property balance tends to decrease.

(3) Blending ratio The blending ratio of the component (1) in the polypropylene resin composition of the present invention is 35 to 50% by weight, preferably 40 to 45% by weight, based on the entire polypropylene resin composition. When the blending ratio of the component (1) is less than 35% by weight and exceeds 50% by weight, the moldability (high fluidity) and coating appearance quality of the polypropylene resin composition and the molded body thereof may be deteriorated. In addition, the mechanical property balance and the linear expansion coefficient are also deteriorated.
In addition, as long as a component (1) is in the above-mentioned characteristic range, two or more kinds may be used in combination.

2. Component (2): Ethylene / α-olefin copolymer The ethylene / α-olefin copolymer of component (2) used in the present invention is a random copolymer of ethylene and α-olefin, and is rubbery. Although it is a polymer (elastomer) having properties, the melt flow rate (230 ° C., 2.16 kg load) needs to be 2 to 30 g / 10 min. If the MFR is less than 2 g / 10 minutes, the coating appearance quality and the linear expansion coefficient may be deteriorated. On the other hand, if the MFR is larger than 30 g / 10 min, the mechanical property balance may be deteriorated.
In the present invention, component (2) is an ethylene / α-olefin copolymer, which has a high dimensional stability (low linear expansion coefficient) and high physical properties due to a synergistic effect with other component (3). It is considered to be a polypropylene resin composition that is excellent in balance (high rigidity, high impact strength) and in appearance quality.

(1) Manufacturing method The manufacturing method of the component (2) used for this invention is not specifically limited, It can superpose | polymerize using a metallocene catalyst, a vanadium catalyst, a Ziegler catalyst, etc. Examples of the α-olefin to be copolymerized include propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and the like. Of these, 1-butene, 1-hexene and 1-octene are preferable. Two or more of these may be copolymerized.

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. A preferable production method includes a high-pressure bulk polymerization method and a solution method.

Specific examples of the component (2) include, for example, an ethylene / propylene copolymer (EPR), an ethylene / butene copolymer (EBR), an ethylene / hexene copolymer (EHR), and an ethylene / octene copolymer (EOR). And the like, and may be referred to as ethylene rubber, elastomer, plastomer and the like. Examples of the shape include pellets, crumbs, granules and the like, but are not particularly limited and can be used.
In the present invention, the component (2) is not limited to one type, and may be a mixture of two or more different types such as density and MFR. Examples of commercially available products include EP series manufactured by JSR, Tuffmer P series and Tuffmer A series manufactured by Mitsui Chemicals, Engage EG series manufactured by Dow Chemical Japan, and affinity. Particularly preferred are Engage EG8842, EG8407, EG8180 manufactured by Dow Chemical Japan, and Toughmer A4050S manufactured by Mitsui Chemicals.

(2) Physical properties It is necessary that the melt flow rate (230 ° C., 2.16 kg load) of the component (2) is 2 to 30 g / 10 minutes. If the MFR is less than 2 g / 10 minutes, the coating appearance quality and the linear expansion coefficient may be deteriorated. On the other hand, when the MFR is larger than 30 g / 10 min, the mechanical property balance deteriorates. Here, the MFR value may be a value of one kind of component (2) or a value of a mixture of two or more kinds of components (2).

(3) Blending ratio The blending ratio of the component (2) in the polypropylene resin composition of the present invention is 15 to 25% by weight, preferably 20 to 25% by weight, based on the entire polypropylene resin composition. If the blending ratio of component (2) is less than 15% by weight, the linear expansion coefficient of the polypropylene resin composition and the molded product thereof is increased, and the impact strength may be lowered, and the content exceeds 25% by weight. Then, there is a risk that the rigidity is lowered.
In addition, 2 or more types of a component (2) may be used together if it is in the range of the above-mentioned characteristic.

3. Component (3): Talc The talc of the component (3) used in the present invention is required to have an aspect ratio of 15 to 17 and an average particle size of 6 to 8 μm. Component (3) is used for the purpose of improving the dimensional stability (reducing the linear expansion coefficient) of the polypropylene-based resin composition and its molded article, improving the balance of physical properties with a focus on rigidity, and improving environmental adaptability. However, in the present invention, talc satisfies the above-mentioned characteristics. This is due to a synergistic effect with the other component (2), and high dimensional stability (low linear expansion coefficient) and high physical property balance (high rigidity). , High impact strength), and a polypropylene resin composition that is excellent in coating appearance quality.

(1) Shape, etc. The talc shape of the component (3) is not particularly limited as long as the aspect ratio is 15 to 17 and the average particle size is 6 to 8 μm, and is granular, plate-like, rod-like, fibrous, Any shape such as a whisker shape can be used. Moreover, what is marketed as a filler for polymers can also be used.
The talc of component (3) needs to have an aspect ratio of 15-17. If the aspect ratio is less than 15, the linear expansion coefficient may be high, and if it is greater than 17, the dimensional stability and mechanical property balance (especially impact strength) may be deteriorated.
In addition, the talc of the component (3) needs to have an average particle size of 6 to 8 μm. If the average particle size is smaller than 6 μm and larger than 8 μm, the mechanical property balance (especially impact strength) may be deteriorated.
In this specification, the aspect ratio of talc is a value representing the ratio of the long side to the short side of talc, and is obtained from the measured value by selecting ten talc having a large aspect ratio using a microscope or the like. It is what
In the present specification, the average particle size of talc means the particle size at an integrated value of 50% in the particle size distribution obtained by a laser diffraction / scattering particle size distribution analyzer or the like. -920 type is mentioned.
The talc of component (3) may be a mixture of two or more talc as long as it satisfies the above characteristics.

The manufacturing method of a component (3) is not specifically limited, It manufactures with a well-known various manufacturing method. In the case of talc, the raw stone is manufactured by pulverizing with an impact pulverizer or micron mill type pulverizer, or further pulverized with a jet mill or the like and then classified and adjusted with a cyclone or micron separator. Specifically, the aspect ratio and average particle diameter of the talc of component (3) can be adjusted by the pulverization time.
These can be produced in the form of chopped strands, compressed souls, pellets (granulated), granules, etc., in addition to general powders and rovings, with improved handling convenience. Many can be used. Of these, powder, compressed soul, and granule are preferable.

  Component (3) is a surface treated with an organic titanate coupling agent, an organic silane coupling agent, an unsaturated carboxylic acid, or a modified polyolefin grafted with an anhydride thereof, a fatty acid, a fatty acid metal salt, a fatty acid ester, or the like. Alternatively, two or more kinds may be used in combination for surface treatment.

(2) Blending ratio The blending ratio of the component (3) in the polypropylene resin composition of the present invention is 35 to 40% by weight based on the entire polypropylene resin composition. When the blending ratio of the component (3) is less than 35% by weight, the dimensional stability of the polypropylene resin composition and the molded product thereof is decreased (the linear expansion coefficient is increased), and the rigidity is decreased. If it exceeds wt%, the appearance quality of the paint may be deteriorated. In addition, a component (3) may use 2 or more types of talc together.

4). Component (4): Optional addition component In the polypropylene resin composition of the present invention, in addition to the above component (1), component (2), and component (3), the effects of the present invention are not significantly impaired as necessary. In the range, for example, an optional additive component (4) can be blended in order to further improve the desired effect or to impart other effects. The addition amount is 0.2 to 2.0% by weight based on the entire polypropylene resin composition.
Specific optional components include non-ionic antistatic agents, hindered amine light stabilizers, benzotriazole ultraviolet absorbers, physical foaming agents, and organic metal salt dispersions. Agents, coloring agents such as pigments, antioxidants such as phenols, neutralizing agents such as inorganic compounds, lubricants such as fatty acid amides, metal deactivators such as nitrogen compounds, nonionic surfactants, thiazoles, etc. Antibacterial / antifungal agents such as halogen compounds, flame retardants such as halogen compounds, fluorescent brighteners, bubble prevention (antifoaming) agents, crosslinking agents, peroxides, process oils (blending oils), antiblocking agents, plasticizers, Polyolefins such as polypropylene other than the above components (1) and (2), thermoplastic resins such as polyamide and polyester, fillers, elastomers (rubber-like polymers), other additives, etc. It can be mentioned. These components may be used in combination of two or more, may be added to the composition, may be added to each component, and may be used in combination of two or more in each component.

  Antistatic agents, particularly nonionic and cationic antistatic agents, are effective in imparting and improving the antistatic properties of polypropylene resin compositions and molded articles thereof. Specific examples thereof include polyoxyethylene alkyls. Examples include amines; polyoxyethylene alkylamides; polyoxyethylene alkylphenyl ethers; stearic acid monoglycerides; alkyldiethanolamines; alkyldiethanolamides; alkyldiethanolamine fatty acid monoesters;

  Examples of light stabilizers and ultraviolet absorbers include hindered amine-based, benzotriazole-based, benzophenone-based, salicylate-based compounds, and the like, and these provide the weather resistance and durability of polypropylene resin compositions and molded articles thereof. It is effective for improvement. As specific examples of these, hindered amines include condensates of dimethyl succinate and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine; poly [[6- ( 1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [ (2,2,6,6-tetramethyl-4-piperidyl) imino]]; tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate; Tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate; bis (1,2,2,6,6-pentamethyl-4-piperidyl) Sebake Bis-2,2,6,6-tetramethyl-4-piperidyl sebacate and the like, but for benzotriazole series, 2- (2′-hydroxy-3 ′, 5′-di-t-butylphenyl) -5-chlorobenzotriazole; 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5-chlorobenzotriazole and the like include 2-hydroxy-4-methoxybenzophenone in benzophenone series 2-hydroxy-4-n-octoxybenzophenone and the like for salicylates, 4-t-butylphenyl salicylate; 2,4-di-t-butylphenyl 3 ′, 5′-di-t-butyl- Examples thereof include 4′-hydroxybenzoate.

  Examples of the foaming agent include physical foaming agents and chemical foaming agents, and these are effective for reducing the weight of the polypropylene-based resin composition and its molded product, and for imparting and improving rigidity and dimensional characteristics. Specific examples thereof include carbon dioxide gas; nitrogen gas; air; propane; butane; dichlorodifluoromethane and the like for physical foaming agents; citric acid; baking soda; azodicarbonamide; benzenesulfonylhydrazide; Examples include toluenesulfonyl hydrazide; N, N′-dimethyl-N, N′-dinitrosotephthalamide; P-toluenesulfonyl semicarbazide.

  Examples of the dispersant include organic metal salts, which increase the dispersibility of inorganic fillers and coloring pigments, and the rigidity, heat resistance, weld appearance, flow mark appearance, texture, etc. of the polypropylene resin composition and its molded product. It is effective for imparting and improving. Specific examples thereof include calcium stearate; magnesium stearate; calcium behenate; magnesium behenate; zinc behenate; zinc montanate; calcium montanate;

Examples of the colorant include inorganic and organic pigments, and the addition and improvement of the colored appearance, appearance, texture, commercial value, weather resistance and durability of the polypropylene resin composition and its molded product. This is effective.
Specific examples of the inorganic pigment include titanium oxide; iron oxide (eg, bengara); chromic acid (eg, galvanized lead); molybdic acid; selenide sulfide; ferrocyanide and carbon black. A poorly soluble azo lake; a soluble azo lake; an insoluble azo chelate; a condensable azo chelate; an azo pigment such as other azo chelates; a phthalocyanine pigment such as phthalocyanine blue; a phthalocyanine green; an anthraquinone; a perinone; a perylene; Rake; quinacridone series; dioxazine series; isoindolinone series and the like. Moreover, in order to make a metallic tone or a pearl tone, an aluminum flake; a pearl pigment can be contained. Moreover, dye can also be contained.

[II] Characteristics and production of polypropylene resin composition for automobile exterior members Characteristics The polypropylene resin composition for automobile exterior members of the present invention is the above-described component (1), component (2), component (3), and further, if necessary, component (4) blended in the above blending ratio. Thus, it is preferable that the following characteristics (1) to (4) are all satisfied simultaneously.
Characteristics (1) Melt flow rate (according to ASTM-D1238, 230 ° C., 2.16 kg load) is 30 to 40 g / 10 min. Characteristics (2) Flexural modulus (according to ASTM-D790, 23 ° C.) is 2500 to 3500 MPa.
Characteristic (3) Izod impact strength (according to ASTM-D785, 23 ° C.) is 200 to 350 J / m
Characteristic (4) Linear expansion coefficient (based on JIS K7197) is 4 × 10 ⁻⁵ / ° C. or less

(1) Characteristic (1): MFR
The polypropylene resin composition for automobile exterior members of the present invention preferably has a melt flow rate (230 ° C., 2.16 kg load) of 30 to 40 g / 10 minutes. If the MFR is less than 30 g / 10 minutes, the moldability (high fluidity) of the polypropylene resin composition and the molded body thereof may be deteriorated. On the other hand, if the MFR is larger than 40 g / 10 min, the mechanical property balance may be deteriorated.
Moreover, in this specification, MFR is a value measured by 230 degreeC and a 2.16kg load based on ASTM-D1238 as above-mentioned.

(2) Characteristic (2): Flexural modulus The polypropylene resin composition for automobile exterior members of the present invention preferably has a flexural modulus (23 ° C.) of 2500 to 3500 MPa. If the flexural modulus is less than 2500 MPa, it cannot be said that the polypropylene resin composition and the molded body thereof have sufficient rigidity. On the other hand, if the flexural modulus is greater than 3500 MPa, the impact value may be reduced.
Moreover, in this specification, a bending elastic modulus is the value measured at 23 degreeC based on ASTM-D790.

(3) Characteristic (3): Izod impact strength The polypropylene resin composition for automobile exterior members of the present invention preferably has an Izod impact strength (23 ° C) of 200 to 350 J / m. If the Izod impact strength is less than 200 MPa, it cannot be said that the mechanical properties of the polypropylene resin composition and the molded product thereof are sufficient. On the other hand, if the Izod impact strength is greater than 350 J / m, the rigidity may deteriorate.
In the present specification, the Izod impact strength is a value measured at 23 ° C. in accordance with JIS K7110.

(4) Characteristic (4): Linear expansion coefficient The polypropylene resin composition for automobile exterior members of the present invention preferably has a linear expansion coefficient of 4 x ^10-5 / ° C or less. When the linear expansion coefficient is larger than 4 × 10 ⁻⁵ / ° C., it cannot be said that the dimensional stability of the polypropylene resin composition and the molded body thereof is sufficient.
Moreover, in this specification, a linear expansion coefficient is the value measured in the temperature range of -30-80 degreeC based on JISK7197.

2. Manufacture and Molding The polypropylene resin composition of the present invention comprises the above component (1), component (2), component (3), and, if necessary, component (4) in the above blending ratio. In addition, it is produced by kneading and granulating using a normal kneader such as a twin screw extruder, Banbury mixer, roll mixer, Brabender-plastograph, kneader.

  In this case, it is desirable to select a kneading and granulating method capable of improving the dispersion of each component, and usually a twin screw extruder is used. In this kneading and granulation, the above-mentioned components may be kneaded at the same time, or each component may be divided to improve performance, for example, first, a part of component (1) and component (3) Alternatively, the whole can be kneaded, and then the remaining components can be kneaded and granulated. In addition, in order to avoid breakage of the component (3), etc., it is fed to the molten resin portion from a feed port (side feed port) provided in the middle part of the extruder cylinder, etc., and kneaded and granulated. You can also.

The polypropylene resin composition is preferably molded by injection molding (including gas injection molding) or injection compression molding (including press injection, hot flow stamping molding, and gas injection compression molding). In addition, a desired molded article can be obtained by combining a technique of injection compression molding with a so-called foam molding technique or expansion molding technique.
For the molding of the polypropylene resin composition, various types of molding such as hollow molding, extrusion molding, compression (press) molding, foaming (expansion) molding, sheet molding, thermoforming, stamping molding, powder molding, etc., as necessary. A molding method can also be applied, whereby a desired molded body can be obtained.

[III] Automotive Exterior Member The automotive exterior member of the present invention is an automotive exterior member obtained by injection molding the above-described polypropylene resin composition for automotive exterior members of the present invention.
Moreover, it is preferable that the web exterior average value of the coating surface of the automobile exterior member of the present invention is 30 or less.
In addition, in this specification, the web scan average value is applied to an automobile exterior member, and among the measurement values obtained by measuring the surface using BYK-Gardner, a microwave scan, Wu, Wa, It is the average value of each value of Wb, Wc, and Wd.

Here, the web scan is a method for measuring the undulation in the wavelength range of about 0.1 to 30 mm on the painted surface of an automobile or the like. By this measurement, it is possible to quantify the appearance quality that the coated surface is highly glossy and smooth, for example, orange peel. This appearance quality is determined by the reflection of light depending on the uneven pattern on the painted surface and can be visually evaluated by humans. Optically, the painted surface is measured by measuring the wavelength bright / dark pattern like the human eye. A method of simulating visual recognition is web scanning. As a measuring apparatus, a microwave-scan (byg-gardner) and the like are known.
In this microwave scan, a laser point light source irradiates laser light at a specific angle from a normal to the coating surface, and a detector measures reflected light at the same angle opposite to the normal. This apparatus can detect the optical profile of the coating surface by measuring the brightness / darkness of the reflected light one by one at a predetermined interval by moving the laser point light source over the coating surface and scanning. The detected optical profile can be spectrally analyzed through a frequency filter to analyze the paint substrate, interior, and surface structure. For example, the characteristic spectrum of this measuring apparatus is divided into a plurality of regions as follows.
Wu: Wavelength 0.1 mm or less Wa: Wavelength 0.1-0.3 mm
Wb: Wavelength 0.3-1 mm
Wc: Wavelength 1-3mm
Wd: wavelength 3 to 10 mm
We: Wavelength 10-30mm
Sw: Wavelength 0.3 to 1.2 mm
Lw: Wavelength 1.2 to 12 mm
DOI: Wavelength 0.3mm or less

The coating on the automotive exterior member of the present invention is not particularly limited, and a coating used for a normal automotive exterior member can be adopted. However, the automotive exterior member of the present invention performs micro-wave scanning on the painted surface. Among the measured values measured using, the average value of each value of Wu, Wa, Wb, Wc, and Wd of the following wavelengths (1) to (5) can be 30 or less, which is preferable.
Wavelength (1) Wu <0.1mm
Wavelength (2) Wa 0.1-0.3mm
Wavelength (3) Wb 0.3-1mm
Wavelength (4) Wc 1-3mm
Wavelength (5) Wd 3-10mm
When the average value is 30 or less, it can be said that the coating surface is sharp and the coating appearance quality is good. On the other hand, if the average value is greater than 30, the coating surface is not sharp and is visually observed like an orange peel, and the coating appearance quality may not be good.

Molded articles or parts using the polypropylene resin composition for automobile exterior members of the present invention have moldability (high fluidity), dimensional stability (low linear expansion coefficient), and balance of physical properties (high rigidity, high impact strength). An automotive exterior part is most preferable as its application because it is excellent and good paint appearance quality is obtained. For example, by using the polypropylene-based resin composition for automobile exterior parts of the present invention as automobile exterior parts such as bumpers, side moldings, back doors, and fenders, high dimensional stability (low linear expansion coefficient) and advanced It is preferable because a component having excellent physical properties (high rigidity, high impact strength) and excellent appearance quality can be obtained.
In addition, since the molded object or component using the polypropylene resin composition for automobile exterior parts of the present invention is an automobile exterior part, it exhibits the characteristics as described above. Can also be suitably used for various molded articles in the field of industrial parts.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
The physical property measurement, evaluation, and analysis methods and materials used in the examples are as follows.

1. Physical property measurement, evaluation method, analysis method (1) MFR: Measured according to ASTM-D1238 (230 ° C., 21.18 N).
(2) Flexural modulus: measured in accordance with ASTM-D790 (23 ° C., test speed 2 mm / min).
(A) Test piece: thickness 6.4 mm, width 12.7 mm, length 127 mm
(B) Test conditions: Test temperature = 23 ° C., distance between fulcrums = 102.4 mm, test speed = 2.0 mm / min (3) Izod impact strength: Measured according to ASTM-D785 (23 ° C.).
(A) Test piece: Notched (notch radius 0.25 mm), thickness 6.4 mm, width 12.7 mm, length 63.5 mm
(B) Test conditions: Test temperature = 23 ° C.
(4) Linear expansion coefficient: Measured according to JIS-K7197 (measurement range -30 ° C to 80 ° C).
Test piece = 10 mm × 10 mm × 3 mm ... Prepared by injection molding.
Temperature increase rate = 2 ° C./min, load = 4 kPa, measurement range = −30 ° C. to 80 ° C.
Here, it can be said that the smaller the linear expansion coefficient, the better the dimensional stability.
(5) Web scan average value: The test piece was coated with a urethane-based resin paint (coating film thickness 50 μm), and the surface thereof was measured using a micro-wave scan manufactured by BYK-Gardner.
The lower the web scan measurement value, the higher the surface sharpness, and the average of the measurement values Wu, Wa, Wb, Wc, Wd was taken as the web scan average value.

2. Materials In the examples and comparative examples, the following materials were used.
(1) Component (1): Polypropylene resin PP-1: Propylene / ethylene random copolymer polymerized using a metallocene catalyst, melt flow rate (MFR) 30 g / 10 min, melting peak temperature 142 ° C. PP-2: Propylene / ethylene random copolymer polymerized using metallocene catalyst, melt flow rate (MFR) 25 g / 10 min, melting peak temperature 127 ° C. PP-3: polymerized using Ziegler catalyst A propylene / ethylene block copolymer having a melt flow rate (MFR) of 105 g / 10 min, a melting peak temperature of 162 ° C., and a crystallinity of a melt flow rate (230 ° C., 2.16 kg load) of 195 g / 10 min or more. It consists of a propylene polymer part and an ethylene / propylene copolymer part. Ratio of ethylene-propylene copolymer portion to the whole alkylene block copolymer is 13.5 wt%. The method for measuring the ratio of the MFR of the crystalline propylene polymer portion and the ethylene / propylene copolymer portion is as described above.
The melting peak temperature (Tm) is a melting peak temperature measured by the DSC method, and using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.), the sheet-shaped sample piece is packed in a 5 mg aluminum pan, The temperature is raised from 50 ° C. to 200 ° C. at a heating rate of 100 ° C./min, held for 5 minutes, then cooled to 40 ° C. at 10 ° C./min, crystallized and held for 1 minute, at 10 ° C./min. This is a value measured as the maximum melting peak temperature when the temperature is raised to 200 ° C.
PP-1 to PP-3 are shown together in Table 1.

(2) Component (2): Ethylene / α-olefin copolymer (elastomer)
Elastomer A: Ethylene / Butene Copolymer “A4050S” (trade name) manufactured by Mitsui Chemicals, Inc.
Elastomer B: manufactured by DuPont Dow, ethylene / octene copolymer “EG8842” (trade name)
Elastomer C: Ethylene octene copolymer “EG8407” (trade name) manufactured by DuPont Dow
Elastomer D: ethylene / octene copolymer “EG8180” (trade name) manufactured by DuPont Dow
Elastomer A to Elastomer D are shown together in Table 2.

(3) Component (3): Talc Talc A: Ten talcs having a large aspect ratio are selected from an image magnified by a microscope or the like, the average aspect ratio is 7.5, and the average particle diameter is 5 μm. Talc B: Ten talcs having a large aspect ratio are selected from an image magnified by a microscope or the like, the average aspect ratio is 16, and the average particle diameter is 6 to 8 μm. The average particle diameter is determined by laser diffraction. This is the particle size at an integrated value of 50% in the particle size distribution determined by a scattering method particle size distribution meter, etc., and Horiba LA-920 type was used as a measuring device.
Table 3 summarizes talc A and talc B.
(4) Component (4): Optional additional components Carbon fiber: Toray Industries, Inc., trading card TS12 (trade name)

3. Examples and Comparative Examples The components (1) to (4) above were blended in the proportions shown in Table 4, and after dry blending using a super mixer, the raw materials were supplied from a hopper, and KCM twin screw extrusion manufactured by Kobe Steel Various test pieces were prepared from a pellet obtained by melt-kneading using a machine at an injection molding machine with a clamping force of 350 tons at a molding temperature of 210 ° C. and a mold temperature of 30 ° C., and evaluated. The results are shown in Table 4. In Table 4, the unit of the blending ratio is% by weight.

4). Evaluation As shown in Table 4, the polypropylene-based resin composition having the composition shown in Examples 1 and 2 that satisfies the respective requirements in the essential constituent elements of the present invention, and a member obtained by injection molding the same, All have good formability (high fluidity), physical property balance (high rigidity, high impact strength), dimensional stability (low linear expansion coefficient) and excellent paint appearance quality, industrial parts, preferably Automotive parts such as door trims, instrument panels, pillars, bumpers, side moldings, door protectors, side protectors, back doors, fenders, rear gates, various parts for fenders such as fender accessory parts, particularly preferably bumpers, Performance suitable for automotive exterior parts such as back doors, fenders, rear gates and fender accessories It was confirmed that it had clearly.

On the other hand, a polypropylene resin composition having the composition shown in Comparative Examples 1 and 2 and a member obtained by injection molding the same have poor performance balance.
For example, in Comparative Example 1, the moldability (high fluidity), physical property balance (high rigidity, high impact strength), and excellent coating appearance quality of the resin composition are the same as in the examples, but the dimensional stability. There was a significant difference in (linear expansion coefficient). This means that the dimensional stability (linear expansion coefficient) is remarkably improved by the component (2) and the component (3), and it is essential that the component (2) and the component (3) satisfy the scope of the present invention. Show.
In Comparative Example 2, the dimensional stability (linear expansion coefficient) is equivalent to that of the example, but the moldability (high fluidity), physical property balance (high rigidity, high impact strength), and excellent coating. There was a significant difference in appearance quality. This is because component (1) and component (3) satisfying the scope of the present invention are blended with other components, so that excellent moldability (high fluidity), dimensional stability (linear expansion coefficient) and physical properties are obtained. In addition to being balanced (high rigidity, high impact strength), it is essential to significantly improve the appearance quality of the paint.

  From the results of the examples and comparative examples described above, the rationality and significance of the configuration and requirements of the present invention are verified, and the superiority of the present invention over the prior art is also apparent.

The polypropylene resin composition for automotive exterior members and automotive exterior members using the same according to the present invention have moldability (high fluidity), dimensional stability (low linear expansion coefficient), physical property balance (high rigidity, high impact strength). With excellent paint appearance quality and industrial parts, preferably automotive parts such as door trims, instrument panels, pillars, bumpers, side moldings, door protectors, side protectors, back doors, fenders, rear gates, fenders It has performance suitable for automobile parts such as various parts around the fender such as accessory parts, particularly preferably for automobile exterior parts such as bumpers, back doors, fenders, rear gates, and fender accessory parts.

Claims (5)

The following components (1) to (3) are 35 to 50% by weight of component (1), 15 to 25% by weight of component (2), and 35 of component (3) based on the entire polypropylene resin composition. A polypropylene resin composition for automobile exterior members, characterized in that it is contained in a proportion of ˜40% by weight ,
Furthermore, the melt flow rate (230 ° C., 2.16 kg load) of the entire polypropylene resin composition is 30 to 40 g / 10 minutes, and
The web scan average value of the coating surface when the coating film thickness of 50 μm is applied by the urethane resin paint is 30 or less.
The polypropylene resin composition for automobile exterior members.
Component (1) Polypropylene resin having a melt flow rate (230 ° C., 2.16 kg load) of 100 to 110 g / 10 min and a melting peak temperature of 160 to 165 ° C. and polymerized using a Ziegler catalyst Component (2) Melt Ethylene / α-olefin copolymer having a flow rate (230 ° C., 2.16 kg load) of 2 to 30 g / 10 min Component (3) Talc having an aspect ratio of 15 to 17 and an average particle diameter of 6 to 8 μm   Component (1) is a propylene / ethylene comprising a crystalline propylene polymer portion having a melt flow rate (230 ° C., 2.16 kg load) of 190 g / 10 min to 220 g / 10 min and an ethylene / propylene copolymer portion. It is a block copolymer, The polypropylene-type resin composition for motor vehicle exterior members of Claim 1 characterized by the above-mentioned.   3. The polypropylene resin composition for an automotive exterior member according to claim 2, wherein the proportion of the ethylene / propylene copolymer portion is 10 to 20% by weight with respect to the entire propylene / ethylene block copolymer. The polypropylene resin composition for automobile exterior members according to any one of claims 1 to 3, wherein the following characteristics (2) to (4) are satisfied .
Characteristic (2) Flexural modulus (according to ASTM-D790, 23 ° C.) is 2500 to 3500 MPa
Characteristic (3) Izod impact strength (according to ASTM-D785, 23 ° C.) is 200 to 350 J / m
Characteristics (4) Linear expansion coefficient (based on JIS-K7197) is 4 × 10 ⁻⁵ / ° C. or less   An automobile exterior member obtained by injection molding the polypropylene resin composition for an automobile exterior member according to any one of claims 1 to 4.

Images