JP2005187623A - Propylene resin composition and molded article thereof - Google Patents

Abstract

Provided is a propylene-based resin composition excellent in the balance between paintability, in particular, electroconductivity capable of electrostatic coating and mechanical properties, on the premise of primer-less coating of a water-based paint, and a molded body using the same.
(A) A propylene homopolymer portion having an MFR of 50 to 400 g / 10 min, an IPF of 0.98 or more, a propylene content of 50 to 85 wt%, a Tg of −40 ° C. or less, an intrinsic viscosity [ [eta]] consisting of a propylene / ethylene random copolymer portion having a molecular weight of 5 to 9 dl / g, 100 weight of propylene / ethylene block copolymer having an MFR of 25 to 80 g / 10 min, and (b) a diene having a hydroxyl group at the terminal. 0.1 to 15 parts by weight of a polymer or hydrogenated product thereof, (c) 1 to 40 parts by weight of conductive carbon having a particle diameter of 10 to 100 nm and a DBP absorption of 50 to 600 ml / 100 g are obtained as essential components. The propylene-based resin composition whose O / C by the X ray electron spectroscopy of the surface of the molded object obtained is 0.2 to 2%.
[Selection figure] None

Description

  The present invention relates to a propylene-based resin composition excellent in paintability and a molded body thereof, and particularly relates to a propylene-based resin composition excellent in balance between paintability and mechanical properties and a molded body thereof.

Polypropylene is widely used as an injection molding material in the industrial parts field represented by home appliance parts. In particular, polypropylene materials are used as a main material in home appliances such as televisions, refrigerators, washing machines and vacuum cleaners, and toiletries such as toilet seats.
In many cases, these parts are painted on the surface in order to impart design properties. However, since polypropylene has poor adhesion to the paint film, it is devised to apply a primer to the surface of the polypropylene part to bring the paint film into close contact. Has been made.

However, since this primer contains an organic solvent as a solvent, it causes discharge VOC and increases the environmental load.
For this reason, an attempt has been made to reduce the environmental burden by imparting coating film adhesion to polypropylene so that the coating film is adhered without applying the primer component.
For example, as a coating modifier, a compound having at least one unsaturated bond in the molecule and having a hydroxyl group (for example, see Patent Document 1), a styrene / unsaturated glycidyl ester copolymer and polypropylene. A graft copolymer (for example, refer to Patent Document 2), a diene polymer having a hydroxyl group at its terminal or a hydrogenated product thereof (for example, refer to Patent Documents 3 to 8), and the like are made of polypropylene, propylene-ethylene block copolymer, ethylene. -A method of kneading a polypropylene resin composition composed of a propylene copolymer rubber, an inorganic filler, etc., and adhering the coating film to the molded product obtained therefrom without applying a primer is shown. However, in these methods, in order to adhere the coating film, a large amount of coating modifier must be added, and this has the disadvantage that mechanical properties such as impact strength are greatly reduced. It was. Although there are proposals to reduce the amount of inorganic filler used by using modified polypropylene or surface-modified inorganic filler, impact resistance is still insufficient, and further improvement is desired.
Furthermore, due to the recent demand for reducing the environmental impact, it is also desired to change the paint solvent from the conventional organic solvent to water, and with this, the wettability between the paint solvent and polypropylene is reduced. Compared with the case of using a solvent-based paint, a larger amount of coating modifier must be added. In the conventional method, in order to satisfy the paintability of water-based paint, mechanical properties are greatly sacrificed. It was necessary to do. For this reason, the development of a propylene-based resin composition capable of primerless coating, which has an excellent balance between paintability and mechanical properties for water-based paints, has been awaited.

On the other hand, the electrostatic coating method has become mainstream as a coating method for these industrial parts. Originally, polypropylene is an electrically insulating material and has poor reactivity with a paint resin component, so electrostatic coating is impossible with a single polypropylene resin. In order to solve such a drawback, for example, a method of applying a conductive primer to the surface of a molded product and applying electrostatic coating to a polypropylene base material (see, for example, Patent Documents 9 to 10) has been proposed.
However, although this conductive primer has difficulty in dispersibility of the conductive filler blended to impart conductivity and can be electrostatically coated, there is a problem in the quality of the painted surface after coating. .
Furthermore, a method for imparting conductivity by adding conductive carbon to polypropylene is also known. However, since the fluidity of the polypropylene resin composition is significantly reduced with the addition of conductive carbon, In injection molding applications, however, there was a problem in the molding processability.
Japanese Patent Laid-Open No. 62-257946 JP-A-9-48885 Japanese Patent Laid-Open No. 5-15844 Japanese Patent Laid-Open No. 5-179083 Japanese Patent Laid-Open No. 5-179100 JP-A-7-53914 Japanese Patent Laid-Open No. 9-71713 JP 2000-273271 A JP 58-76265 A JP-A-61-218639

  In view of the above-mentioned problems, the present invention is based on the premise of primer-less coating of a paint, and uses a propylene-based resin composition excellent in paintability, in particular, the balance between electrical conductivity capable of electrostatic coating and mechanical properties, and the same. It is an object to provide a molded body.

  As a result of earnest studies on the propylene-based resin composition excellent in the balance of electrical conductivity, paintability and mechanical properties, the present inventors have a propylene / ethylene block copolymer having a specific structure and excellent mechanical property balance. A diene polymer having a hydroxyl group at the terminal or a hydrogenated product thereof is used as a coating modifying component, and the oxygen atom concentration with respect to carbon atoms on the surface of the molded article of the resin composition using a specific conductive carbon is 0.2-2. %, It was found that a propylene-based resin composition having an excellent balance of mechanical properties, molding processability, paintability, and conductivity was found, and the present invention was completed.

That is, according to the first invention of the present invention, the following components (a), (b) and (c) are essential components, and melt flow rate (JIS K7210, temperature 230 ° C., load 21.18 N, hereinafter MFR). Is a resin composition of 0.1 to 100 g / 10 min, and an oxygen atom relative to a carbon atom measured by X-ray photoelectron spectroscopy (XPS • ESCA) on the surface of a molded article obtained from the composition Provided is a propylene-based resin composition having a good balance of conductivity, paintability, and physical properties, wherein the concentration is 0.2 to 2%.
Component (a) A propylene homopolymer portion having an MFR of 50 to 400 g / 10 min, an isotactic pentad fraction of 0.98 or more, a propylene content of 50 to 85 wt%, and a glass transition temperature of −40 ° C. Hereinafter, a propylene / ethylene block copolymer having an intrinsic viscosity [η] measured by a cross-fractionation chromatograph of 5 to 9 dl / g and a propylene / ethylene random copolymer portion having an MFR of 25 to 80 g / 10 min. 100 parts by weight of component (b) diene polymer having a hydroxyl group at the terminal or hydrogenated product 0.1 to 15 parts by weight of component (c) particle size 10 to 100 nm, DBP absorption 50 to 600 ml / 100 g, specific surface area 80 to 1500 m ² / g of conductive carbon 1-40 parts by weight

According to the second invention of the present invention, there is provided a propylene-based resin composition characterized in that, in the first invention, the volume specific resistance value is 10 ⁸ Ωcm or less.

According to the third invention of the present invention, in the first or second invention, the flexural modulus (JIS K7203) is 1400 MPa or more, the bending strength (JIS K7203) is 20 MPa or more, measured at 23 ° C. and −30 ° C. The Izod impact strength (JIS K7110) is 200 and 40 J / m or more respectively, and the deflection temperature under load (JIS K7207) is 100 ° C or more under the condition of 4.6 kgf / cm ^2. A propylene-based resin composition is provided.

  According to the fourth invention of the present invention, the propylene-based resin composition of any one of the first to third inventions is used, and injection molding, compression molding, injection compression molding, hollow molding, and extrusion molding are used. Is provided.

  Further, according to the fifth invention of the present invention, in the fourth invention, the coating adhesion rate of the paint directly applied to the surface of the molded body is 100% as a cross-cut residual rate in the cross-cut peel test. A featured shaped body is provided.

  The propylene-based resin composition of the present invention is excellent in strength balance such as impact strength and flexural rigidity, and can adhere a coating film without applying a solvent primer. The coating film adhesion can be realized with less, not only the organic solvent attributed to the primer, but also the reduction in the amount of organic solvent attributed to the paint solvent, and further the thinning of the molded product, saving energy resources, It is an effective means to solve social problems in recent years, such as protecting the global environment.

The present invention is described in detail below.
1. Propylene Resin Composition The propylene resin composition of the present invention comprises (a) a propylene / ethylene block copolymer, (b) a diene polymer having a hydroxyl group at the terminal or a hydrogenated product thereof, and (c) conductive carbon. It is a propylene-based resin composition as an essential component. Each compounding component is demonstrated below.

(A) Propylene / ethylene block copolymer The (a) propylene / ethylene block copolymer used in the present invention is a copolymer comprising a propylene homopolymer portion and a propylene / ethylene random copolymer portion.

The propylene homopolymer portion has an MFR of 50 to 400 g / 10 minutes, preferably 100 to 300 g / 10 minutes, and more preferably 100 to 200 g / 10 minutes. The MFR of the propylene / ethylene block copolymer is 25 to 80 g / 10 minutes, preferably 30 to 75 g / 10 minutes, and more preferably 35 to 70 g / 10 minutes.
When the combination of the MFR of the propylene homopolymer portion and the MFR of the block copolymer deviates from the above range, the molding processability and impact resistance become poor.
The MFR of the propylene homopolymer portion can be adjusted by controlling the hydrogen concentration during the polymerization of the propylene homopolymer portion.
The MFR of the propylene / ethylene block copolymer is to control the molecular weight of the propylene homopolymer portion and / or control the molecular weight of the propylene / ethylene copolymer portion by polymerization conditions (polymerization temperature, hydrogen concentration, polymerization time, etc.). Can do.
Here, MFR is a value measured at a temperature of 230 ° C. and a load of 21.18 N in accordance with JIS-K7210.

In addition, the isotactic pentad fraction of the propylene homopolymer portion is 0.98 or more, preferably 0.980 to 0.995, more preferably 0.985 to 0.995. When the isotactic pentad fraction is less than 0.98, the molded article has poor rigidity and heat resistance.
The isotactic pentad fraction of the propylene homopolymer portion is controlled by controlling the addition amount of the electron donor (external and / or internal donor) of the polymerization catalyst and further preventing the omission in the polymerization process. It can be adjusted by controlling the chain configuration.
Here, the isotactic pentad fraction is the isotactic ratio of pentad units in a polypropylene molecular chain measured by the method described in Macromolecules, 6, 925 (1973), that is, the method using ¹³ C-NMR. The tick fraction. In other words, the isotactic pentad fraction is the fraction of propylene monomer units at the center of a chain in which five propylene monomer units are connected and meso-bonded. However, peak assignment was performed based on the method described in Macromolecules, 8, 687 (1975). Specifically, the isotactic pentad unit is measured as the intensity fraction of the mmmm peak in the total absorption peak in the methyl carbon region of the ¹³ C-NMR spectrum.

The Mw / Mn of the propylene homopolymer portion is preferably 2.8 to 10, more preferably 3 to 8. If Mw / Mn is less than 2.8, the fluidity in the high shear region becomes poor, and each is not suitable.
The Mw / Mn of the propylene homopolymer portion can be adjusted by polymerizing the homopolymer in multiple stages in continuous polymerization, or by changing the hydrogen concentration at the initial stage and later stage in batch polymerization.
Here, Mw and Mn are values measured by gel permeation chromatography (GPC) under the following conditions.
Apparatus: Waters HLC / GPC 150C
Column temperature: 135 ° C
Solvent: o-dichlorobenzene Flow rate: 1.0 ml / min
Column: manufactured by Tosoh Corporation GMH _HR- H (S) HT 60 cm × 1
Injection volume: 0.15 ml (no filtration treatment)
Solution concentration: 5 mg / 3.4 ml
Sample preparation: Using o-dichlorobenzene, adjust to a 5 mg / 3.4 ml solution and dissolve at 140 ° C. for 1 to 3 hours.
Calibration curve: Polystyrene standard sample is used. Calibration curve order: Primary PP molecular weight: PS × 0.639

The propylene content of the propylene / ethylene random copolymer portion is 50 to 85% by weight, preferably 65 to 85% by weight, more preferably 67 to 80% by weight, and further preferably 67 to 75% by weight. When the propylene content of the copolymer part deviates from the above range, the dispersibility of the copolymer part deteriorates or the toughness decreases, which is not preferable.
The propylene content of the propylene / ethylene copolymer portion can be adjusted by controlling the concentration ratio of propylene and ethylene during the polymerization of the propylene / ethylene copolymer portion.

The glass transition temperature of the propylene / ethylene random copolymer portion is −40 ° C. or lower, preferably −40 to −60 ° C., more preferably −41 to 55 ° C. If the glass transition temperature exceeds −40 ° C., the impact resistance at low temperatures is drastically lowered, which is not preferable.
The glass transition temperature of the propylene / ethylene copolymer portion can be controlled by the copolymerization ratio of ethylene and the copolymerization monomer.
Here, the glass transition temperature of the propylene / ethylene copolymer portion is a value measured by a dynamic solid viscoelasticity measuring apparatus.

The intrinsic viscosity [η] measured by the cross-fractionation chromatograph of the propylene / ethylene random copolymer portion is 5 to 9 dl / g, preferably 5.5 to 8.5 dl / g, more preferably 6 ~ 8 dl / g. When the intrinsic viscosity is less than 5 dl / g, the toughness of the copolymer component itself is inferior, and when it exceeds 9 dl / g, the dispersibility of the copolymer component is lowered, each of which becomes a factor of lowering impact resistance.
The intrinsic viscosity of the propylene / ethylene copolymer portion is controlled by adjusting the amount of hydrogen added when the copolymer component is polymerized.
Here, the intrinsic viscosity of the propylene / ethylene copolymer portion is defined as a propylene / ethylene copolymer portion, which is 40 ° C. soluble fraction separated by cross fractionation (CFC), and the fractionated component is gel permeation chromatography (GPC). It is a value measured under the following conditions.
(I) Analysis device used in CFC measurement (a) Cross fractionation device CFC T-100 (abbreviated as CFC) manufactured by Dia Instruments Co., Ltd.
(Ii) CFC measurement conditions (a) Solvent: orthodichlorobenzene (ODCB)
(B) Sample concentration: 4 mg / mL
(C) Injection volume: 0.4 mL
(D) Crystallization: The temperature is lowered from 140 ° C. to 40 ° C. over about 40 minutes.
(E) Classification method:
The fractionation temperature at the time of temperature-raising elution fractionation is 40, 100, and 140 ° C., and fractionation is performed in 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.
(F) Solvent flow rate during elution: 1 mL / min (ii) Gel permeation chromatography (GPC)
After separation by CFC, three columns of AD806MS manufactured by Showa Denko KK are used in series for the GPC column connected to the latter part of the CFC.

The molecular weight of the propylene / ethylene random copolymer portion is not particularly limited, but in consideration of dispersibility and impact resistance, the weight average molecular weight (Mw) is preferably 200,000 to 3,000,000, more preferably 300,000 to 300,000. 2.5 million, more preferably 400,000 to 2 million.
Further, Mw / Mn of the propylene / ethylene random copolymer portion is 2.6 or more, preferably 2.8 to 4.5.
Here, the weight average molecular weight of the propylene / ethylene random copolymer portion is a value obtained under the same conditions as in the measurement of the propylene homopolymer portion.

The amount of the propylene / ethylene random copolymer portion in the propylene / ethylene block copolymer needs to be selected in such a range that the polypropylene homopolymer portion becomes the matrix phase, preferably 1 to 50% by weight, more preferably 3 to 30% by weight, more preferably 5 to 20% by weight.
The amount of the propylene / ethylene copolymer portion can be adjusted by controlling the ratio of the polymerization amount of the propylene homopolymer portion and the polymerization amount of the propylene / ethylene copolymer portion by the polymerization time or the like.
The concentration of the copolymer portion is a value measured according to a conventional method such as infrared spectroscopy or ¹³ C-NMR method.

This propylene / ethylene block copolymer can be polymerized by any conventionally known method, and examples thereof include a gas phase polymerization method, a bulk polymerization method, a solution polymerization method, and a slurry polymerization method. You may superpose | polymerize in a batch type with a reactor, or may superpose | polymerize in a continuous type combining several reactors.
Polymerization catalysts include titanium compounds such as titanium halides, vanadium compounds, organoaluminum-magnesium complexes such as alkylaluminum-magnesium complexes, alkylalkoxyaluminum-magnesium complexes, and organometallic compounds such as alkylaluminum or alkylaluminum chloride. And so-called Ziegler type catalysts, or metallocene catalysts as shown in WO-91 / 04257. The so-called Kaminsky catalyst combined with alumoxane is generally used as a catalyst called a metallocene catalyst, but includes a catalyst combined with a cocatalyst other than alumoxane, for example, a boron compound or a clay mineral.

(B) Diene polymer having a hydroxyl group at the terminal or a hydrogenated product thereof (b) The diene polymer having a hydroxyl group at the terminal or a hydrogenated product used in the propylene resin composition of the present invention has at least one hydroxyl group at the molecular terminal. It is a low molecular weight polyolefin having a molecular weight of preferably 10,000 or less, more preferably 1,000 to 5,000, and includes liquid, semi-solid and solid polymers at room temperature.
The average number of hydroxyl groups per molecule of component (b) is preferably from 1.0 to 10.0, particularly preferably from 1.5 to 5.0, and the hydroxyl value (mgKOH / g) is preferably from 20 to 100. If the hydroxyl value is less than 20, the reactivity with the coating film is insufficient, and if it exceeds 100, the compatibility with the resin deteriorates.

  The diene polymer having a hydroxyl group at the terminal can be produced by a known method such as radical polymerization method or anion polymerization method using 1,3-diene as a raw material. Specifically, the method etc. which are described in Unexamined-Japanese-Patent No. 51-71391 can be mentioned, for example. In the case of producing by the radical polymerization method, it can be easily obtained by polymerizing a diene monomer using hydrogen peroxide as a polymerization initiator. In the case of producing by the anionic polymerization method, at least one of both ends obtained by polymerizing the conjugated diene using an anionic polymerization catalyst such as an alkali metal or an organic alkali metal compound according to a known method. For example, a monoepoxy compound, formaldehyde, acetaldehyde, acetone, a halogenoalkylene oxide, or a polyepoxy compound may be reacted with a living polymer having a structure in which an alkali metal is bonded to the polymer. As a raw material monomer for these polymers, at least one conjugated diene monomer is used. Examples of the conjugated diene monomer include 1,3-butadiene, 1,3-pentadiene, isoprene, chloroprene, 2,3-dimethyl-1,3-butadiene, 1-phenyl-1,3-butadiene and the like.

As the hydrogenated diene polymer having a hydroxyl group at the terminal, the above-described diene polymer having a hydroxyl group at the terminal is hydrogenated by a conventional method, for example, the method described in JP-A-51-71391. It is obtained. The degree of hydrogenation may be one in which the double bonds contained in the polymer are wholly or partly hydrogenated. In particular, the iodine value is 0 to 20.0, particularly 0 to 5.0 (g / 100 g) is preferred.
These diene polymers having a hydroxyl group at the terminal and the hydrogenated product thereof can be used alone or as a mixture thereof.

  Specific examples of the diene polymer having a hydroxyl group at the terminal or a hydrogenated product thereof include, for example, polytail H (manufactured by Mitsubishi Chemical Corporation), polyhydroxy-polybutadiene of polytail-A (manufactured by Mitsubishi Chemical Corporation), and the like.

  The amount of component (b) is 0.1 to 15 parts by weight, preferably 1 to 12 parts by weight, more preferably 100 parts by weight of component (a) propylene / ethylene block copolymer. 3 to 10 parts by weight. If the blending amount is less than 0.1 parts by weight, the effect of improving the balance between the coating properties and the mechanical properties is insufficient, and if it exceeds 15 parts by weight, the physical properties such as rigidity and heat resistance are remarkably deteriorated.

(C) Conductive carbon (c) Conductive carbon used in the propylene-based resin composition of the present invention is an essential component for performing electrostatic coating, and is therefore used as a normal coloring or filling compounding agent. It is not a carbon having a regular structure and extremely poor conductivity, but a conductive carbon having a graphite structure in the surface layer. The shape of the conductive carbon is required to have a large ratio of the length to the cross-sectional diameter, such as forming a structure or a tube shape, and there are many pores and a large specific surface area from the viewpoint of conductivity efficiency. It is.
Conductive carbon, the primary particle diameter of 10 to 100 nm, a specific surface area of 80~1500m ² / g, DBP oil absorption quantity indicative of the porosity is or carbon black 50~600cm ³ / 100g, diameter 10 to 100 nm, tube length 0 And at least one conductive carbon selected from carbon nanotubes of 1 to 1000 microns and fullerenes having 60 to 540 carbon atoms, with carbon black being most preferred.
In particular, carbon black has a particle size of preferably 10 to 100 nm, more preferably 15 to 60 nm, still more preferably 20 to 40 nm, and DBP absorption is preferably 50 to 600 ml / 100 g, more preferably 80. To 550 ml / 100 g, more preferably 100 to 500 ml / 100 g, and the specific surface area is preferably 100 to 1500 m ² / g, more preferably 150 to 1500 m ² / g, still more preferably 200 to 1500 m ² / g. .

When the particle diameter, DBP absorption amount, and specific surface area deviate from the above ranges, the development of the structure becomes insufficient, the conductivity of carbon alone decreases, the interaction between carbons increases, As a result, the dispersibility of the conductive carbon decreases, and the conductive efficiency and fluidity of the resin composition decrease, which is not preferable.
Here, the particle diameter is a value measured with a transmission electron microscope, the DBP absorption is a value measured with a dibutyl phthalate absorber meter according to JIS K6221, and the specific surface area is a liquid nitrogen adsorption method. It is a value measured according to (ASTM D3037).

  These conductive carbon blacks can be appropriately selected from commercially available ones. Examples thereof include furnace method carbon black “Mitsubishi Carbon # 3150” commercially available from Mitsubishi Chemical Corporation and shell method carbon black “Ketjen EC” commercially available from Ketjen Black International. These conductive carbons may be used in combination of two or more as required.

  The amount of component (c) is 1 to 25 parts by weight, preferably 2 to 25 parts by weight, more preferably 3 to 20 parts by weight, based on 100 parts by weight of component (a) propylene / ethylene block copolymer. Part. Deviating from the above range is not preferable because sufficient conductivity cannot be obtained or molding processability is greatly reduced.

(D) Optional component In addition to the above-described components, the propylene-based resin composition of the present invention may contain other components as necessary within a range in which the effects of the present invention are not significantly impaired. Good. Examples of such other ingredients include pigments for coloring, antioxidants such as phenols, sulfurs, and phosphoruss, antistatic agents, light stabilizers such as hindered amines, ultraviolet absorbers, and organic aluminum and talc. Examples include various nucleating agents, dispersing agents, neutralizing agents, foaming agents, copper damage inhibitors, lubricants, flame retardants and other additives, inorganic fillers, elastomers such as ethylene elastomers and styrene elastomers, and the like. In addition, although adhesiveness can be improved by adding a modified polypropylene etc., in the composition of this invention, there exists a tendency for impact resistance to deteriorate, and it is unpreferable.

2. Production method of propylene-based resin composition The production method of the propylene-based resin composition of the present invention is not particularly limited, and is produced by mixing and kneading each compounding component by a conventionally known method.
That is, the propylene-based resin composition of the present invention is prepared by blending each blending component in the above blending ratio, and a normal kneader such as a single screw extruder, twin screw extruder, Banbury mixer, roll mixer, Brabender plastograph, kneader or the like. The propylene-based resin composition of the present invention can be obtained by kneading and granulating with the use of.
The propylene-based resin composition of the present invention thus obtained can be used for molding by various known methods. For example, various types of molding by molding by injection molding (including gas injection molding), injection compression molding (press injection), extrusion molding, hollow molding, calendar molding, inflation molding, uniaxially stretched film molding, biaxially stretched film molding, etc. Goods can be obtained. Among these, injection molding, compression molding, and injection compression molding are more preferable.

3. Features of propylene-based resin composition and effects thereof The propylene-based resin composition of the present invention has an oxygen atom concentration relative to carbon atoms measured by X-ray photoelectron spectroscopy (XPS / ESCA) on the surface of a molded article obtained from the resin composition. However, it is 0.2 to 2%.
When the oxygen atom concentration relative to the carbon atoms on the surface of the molded body is less than 0.2%, it indicates that the concentration of the functional group on the surface of the molded body is low, and the adhesion strength of the coating film is weak, causing interface peeling. End up. On the other hand, when the functional group concentration exceeds 2%, the strength of the base material on the surface of the molded body deteriorates, and thus the base material peels off.
Here, the surface oxygen atom concentration is based on X-ray electron spectroscopy (XPS / ESCA), and for example, elemental analysis of the material surface is performed using MgKα as an X-ray source by an ESCA1000 X-ray photoelectron spectrometer manufactured by Shimadzu Corporation. Is required. The oxygen atom concentration at this time means an abundance ratio (O / C) of oxygen (O) atoms and carbon (C) atoms, with a C _1S sensitivity coefficient of 1.00 and an O _1S sensitivity coefficient of 2.85. As described above, the data is processed and calculated using a surface analysis data processing system ESPA 1000.

Moreover, MFR of the propylene-type resin composition of this invention is 0.1-100 g / 10min, Preferably it is 5-80 g / 10min, More preferably, it is 10-50 g / 10min. When the MFR is less than 0.1 g / 10 minutes, injection molding cannot be practically performed, and the balance between paintability, conductivity, and moldability is inferior, and when it exceeds 100 g / 10 minutes, the paintability, moldability, and rigidity are exceeded. Further, the balance of impact strength is deteriorated, and particularly the drop in impact strength becomes remarkable.
Here, MFR is a value measured at 230 ° C. and a 21.18 N load in accordance with JIS-K7210.

Furthermore, the volume resistivity value VR (Ωcm) of the propylene-based resin composition is preferably 10 ⁸ Ωcm or less, more preferably 10 ^{5 to} 5 × 10 ⁷ Ωcm, and particularly preferably 10 ⁶ to 2 × 10 ⁷ Ωcm. .
If the volume resistivity exceeds 10 ⁸ Ωcm, sufficient conductive performance cannot be obtained, and the coating efficiency decreases, so that electrostatic coating cannot be applied substantially without using a conductive primer. .
Here, the volume specific resistance value VR (Ωcm) is a value measured by applying a silver paste to a test piece using an insulation resistance tester and applying voltage of 10V. Specifically, a flat sheet (340 mm × 100 mm) having a thickness of 3 mm is formed by injection molding, and is cut so as to have a width of 20 mm in the longitudinal direction of the flat sheet. A silver paste previously dissolved in butyl acetate is applied to the central portion of the cutting sheet with a brush so that the distance between the electrodes is 90 mm. The strip-shaped test piece coated with the silver paste is measured for the volume resistivity under the condition of an applied voltage of 10 V using an insulation resistance tester (Yokogawa Hewlett Packard 4329A High Resistance Meter).

Furthermore, the flexural modulus (JIS K7203) of the propylene-based resin composition is preferably 1400 MPa or more, more preferably 1450 MPa or more, and the bending strength (JIS K7203) is preferably 20 MPa or more, more preferably 25 MPa or more. The specific gravity is preferably 0.9 to 1.05, and the Izod impact strength (JIS K7110) measured at 23 ° C. and −30 ° C. is preferably 200 and 40 J / m or more respectively, more preferably 220, And the deflection temperature under load (JIS K7207) is preferably 100 ° C. or higher, more preferably 110 ° C. or higher under the condition of 4.6 kgf / cm ² . If each value deviates from the above range, the physical properties as industrial parts are inferior.

4). Propylene Resin Composition Molded Body The propylene resin composition of the present invention can be used for molding by various known methods. For example, various types of molding by molding by injection molding (including gas injection molding), injection compression molding (press injection), extrusion molding, hollow molding, calendar molding, inflation molding, uniaxially stretched film molding, biaxially stretched film molding, etc. You can get a body. Among these, a molded body by injection molding, compression molding, or injection compression molding is preferable.
The molded bodies obtained by these molding methods are excellent in electrical conductivity, and can be electrostatically coated. A coated molded body coated by the electrostatic coating method can be applied without applying a primer component to the surface of the molded body. Can be obtained.
The coating adhesion rate of the paint directly applied on the surface of the molded product of the propylene-based resin composition of the present invention obtained in this way is 100% as a residual rate in the cross-cut peel test. In addition, although an oil-based paint and an aqueous paint can be used as the paint used, the effect of the present invention is more effective when the aqueous paint is used.
The coated molded article using the propylene-based resin composition of the present invention has a high balance of physical properties in rigidity, impact resistance and paintability, and various industrial parts fields, in particular, thinning, high functionality and large size. As a molded product for various industrial parts such as household appliance parts such as TV cases, refrigerator outer plates, washing machine outer plates, toilet seat covers and bathtubs, etc. doing.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the present invention is not limited to these examples as long as the gist thereof is not exceeded, and various physical properties in the examples are measured. The method and raw materials used are as follows.

1. Physical property measurement method (1) MFR (unit: g / 10 min): Measured according to JIS-K7210 at 230 ° C. and 21.18 N load.
(2) Flexural modulus (unit: MPa): measured at 23 ° C. in accordance with JIS-K7203.
(3) Bending strength (unit: MPa): measured at 23 ° C. according to JIS-K7203.
(4) Izod (IZOD) impact strength (unit: J / m): Measured at 23 ° C. and −30 ° C. in accordance with JIS-K7110.
(5) Deflection temperature under load (unit: ° C.): Measured under the condition of 4.6 kgf / cm ² according to JIS-K7207.
(6) Volume resistivity (unit: Ωcm): A flat sheet (340 mm × 100 mm) having a thickness of 3 mm is formed by injection molding, and is cut so as to have a width of 15 mm in the longitudinal direction. Both ends of the cutting sheet are cut to a length of 50 mm, and a silver paste previously dissolved in butyl acetate is applied using a brush so that the distance between the electrodes is 50 mm. The strip-shaped test pieces coated with the silver paste were measured for volume resistivity with a 4329A high resistance meter manufactured by Yokogawa Hewlett-Packard Co. under the condition of an applied voltage of 10V.
(7) Surface oxygen concentration (unit:%): Based on X-ray electron spectroscopy (XPS / ESCA), elemental analysis of material surface using MgKα as an X-ray source by ESCA 1000 X-ray photoelectron spectrometer manufactured by Shimadzu Corporation Determined by doing. The oxygen atom concentration at this time means an abundance ratio (O / C) of oxygen (O) atoms and carbon (C) atoms, with a C _1S sensitivity coefficient of 1.00 and an O _1S sensitivity coefficient of 2.85. And calculated using a surface analysis data processing system ESPA 1000.
(8) Paintability (unit:%): A flat plate molded by injection molding was directly subjected to Aode Recycle S-700 made by Nippon Paint Co., Ltd. using an air spray gun without any pretreatment. Spray applied to 10 microns, baked and dried at 150 ° C. for 20 minutes, then left at room temperature for 48 hours. Thereafter, using a single-edged razor on the surface of the test piece, 11 parallel vertical and horizontal lines are drawn at intervals of 2 mm to make 100 grids. The cellophane adhesive tape (JIS-Z1522) is fully crimped on it, and the work of peeling off at a stretch while maintaining the angle between the coated surface and the adhesive tape at about 30 degrees is repeated 5 times, and the state of the part surrounded by the grid is observed. Then, the number of grids that did not peel is evaluated.

2. Raw material (1) Propylene / ethylene block copolymer The propylene / ethylene block copolymers (BPP-1 to BPP-6) obtained in Production Examples 1 to 6 were used. The physical properties are shown in Table 1.

(Production Example 1)
(I) Production of Ziegler catalyst Into a fully nitrogen-substituted 10 L reactor, 4000 ml of dehydrated and deoxygenated n-heptane was introduced, and then 8 mol of MgCl ₂ and Ti (On-C ₄ H ₉ ) ₄ were introduced. 16 mol was introduced and reacted at 95 ° C. for 2 hours. After completion of the reaction, the temperature was lowered to 40 ° C., and then 960 ml of methylhydropolysiloxane (20 centistokes) was introduced and reacted for 3 hours. The resulting solid component was washed with n-heptane. Next, 1000 ml of n-heptane purified in the same manner as described above was introduced into a 10 L reactor sufficiently purged with nitrogen, and 4.8 mol of the solid component synthesized above was introduced in terms of Mg atoms. Next, 8 mol of SiCl ₄ was mixed with 500 ml of n-heptane, introduced into the flask at 30 ° C. for 30 minutes, and reacted at 70 ° C. for 3 hours. After completion of the reaction, washing with n-heptane was performed. Subsequently, 0.48 mol of phthalic acid chloride was mixed with 500 ml of n-heptane, introduced into the flask at 70 ° C. for 30 minutes, and reacted at 90 ° C. for 1 hour. After completion of the reaction, washing with n-heptane was performed. Next, 200 ml of SiCl ₄ was introduced and reacted at 80 ° C. for 6 hours. After completion of the reaction, it was sufficiently washed with n-heptane to obtain a solid component. The titanium content of this product was 1.3% by weight.
Next, 1000 ml of n-heptane purified in the same manner as described above was introduced into a sufficiently nitrogen-substituted flask, 100 g of the solid component synthesized above was introduced, and (t-C ₄ H ₉ ) Si (CH ₃ ) ( 24 ml of OCH ₃ ) _{2 and} 34 grams of Al (C ₂ H ₅ ) ₃ were contacted at 30 ° C. for 2 hours. After completion of the contact, the catalyst was thoroughly washed with n-heptane to obtain a solid catalyst component mainly composed of magnesium chloride. The titanium content of this product was 1.1% by weight.

(Ii) Production of propylene / ethylene block copolymer Using the solid catalyst component obtained above and triethylaluminum, using a fluidized bed gas phase reactor having a reaction part volume of 280 L as the first polymerization step, a polymerization temperature of 85 Propylene homopolymerization was continuously carried out under the conditions of ° C and a propylene partial pressure of 22 kg / cm ² . At this time, the solid catalyst component was continuously supplied at a rate of 1.8 g / hr, and triethylaluminum was continuously supplied at a rate of 5.5 g / hr. The powder extracted from the first polymerization step is sent to a fluidized bed gas phase reactor having a reaction part volume of 280 L, which is continuously used as the second polymerization step at 25 kg / hr, and propylene and ethylene are continuously copolymerized. It was. 27 kg / hr of polymer was continuously extracted from the second polymerization step. The hydrogen concentration in each polymerization step, controlling the molecular weight by controlling the _{H 2} / propylene = 0.05 molar ratio 1 bath th, _H 2 tank 2nd / (ethylene + propylene) = 0.01 molar ratio did. The ethylene composition of the rubber-like propylene / ethylene copolymer part is controlled by controlling the gas composition of propylene and ethylene in the second polymerization step to a propylene / ethylene = 1/1 molar ratio (BPP). -1) was obtained. [Mmmm] of the propylene homopolymer extracted from the first stage polymerization tank is 0.986, MFR is 180 g / 10 minutes, and MFR of the propylene / ethylene block copolymer extracted from the second stage polymerization tank is 60 g / 10 minutes. Met. The intrinsic viscosity of the propylene / ethylene copolymer part was measured by CFC. CFC measurement uses Dia Instruments CFC T-100, and the measurement conditions are as follows:
(A) Solvent: orthodichlorobenzene (ODCB)
(B) Sample concentration: 4 mg / mL
(C) Injection volume: 0.4 mL
(D) Crystallization: The temperature is lowered from 140 ° C. to 40 ° C. over about 40 minutes.
(E) Classification method:
The fractionation temperature at the time of temperature-raising elution fractionation is 40, 100, and 140 ° C., and the fractions are separated into a total of three fractions.
(F) Solvent flow rate during elution: 1 mL / fractionated fractions were measured by gel permeation chromatography (GPC). The GPC column in the latter part of the CFC was used by connecting three AD806MS manufactured by Showa Denko KK in series.
The glass transition point (Tg) was measured with a dynamic viscoelasticity measuring apparatus (RSA-II manufactured by Rheometrics).

(Production Examples 2 to 4)
A propylene / ethylene block copolymer (BPP-2) was prepared in the same manner as in Production Example 1 except that the amount of hydrogen in the first polymerization step was appropriately changed within the range of 0.03 to 0.07 in terms of H ₂ / propylene molar ratio. To BPP-4). In Production Example 4, the amount of hydrogen in the second polymerization step was polymerized at a H ₂ /(ethylene+propylene)=0.005 molar ratio.

(Production Example 5)
A propylene / ethylene block copolymer (BPP-5) was obtained in the same manner as in Production Example 1 except that the polymerization temperature in the first polymerization step was 90 ° C.

(Production Example 6)
Production Example 1 except that the amount of hydrogen in the first polymerization step is H ₂ /propylene=0.04 molar ratio, and the amount of hydrogen in the second polymerization step is H ₂ /(ethylene+propylene)=0.02 molar ratio. Similarly, a propylene / ethylene block copolymer (BPP-6) was obtained.

(2) Diene polymer having a hydroxyl group at the terminal or a hydrogenated product thereof As a diene polymer having a hydroxyl group at the terminal or a hydrogenated product thereof, Polytail H (Polytail H) and Polytail-A manufactured by Mitsubishi Chemical Corporation were used.

(3) Conductive carbon (C-1) to (C-2) are used as the conductive carbon, and the physical properties are shown in Table 2.
(C-1): Ketjen EC (manufactured by Nippon Ketjen Black Co., Ltd.)
(C-2): Mitsubishi Carbon # 3030 (manufactured by Mitsubishi Chemical Corporation)

(4) Optional components As other optional components, ethylene elastomer, styrene elastomer, and talc shown in Table 3 were used.

(Examples 1-9)
According to the composition shown in Table 4, propylene / ethylene block copolymer, conductive carbon, diene polymer having a hydroxyl group at the terminal or a hydrogenated product thereof, phenolic antioxidant (IRGANOX 1010 manufactured by Ciba Specialty Chemicals) 0.1 After mixing with 0.05 parts by weight of phosphorus-based antioxidant (Irgafos 168 manufactured by Ciba Specialty Chemicals Co., Ltd.) and 0.3 parts by weight of calcium stearate, a screw using a twin screw extruder (TEX30α manufactured by Nippon Steel) It was melt-kneaded at a rotation speed of 300 rpm and an extrusion rate of 15 kg / h to obtain propylene-based resin composition pellets. The obtained pellets were injection molded under conditions of a mold temperature of 40 ° C. and a cylinder temperature of 220 ° C. to obtain various test pieces of the propylene resin composition. Various physical properties were evaluated by the above-described methods using the obtained test pieces. The evaluation results are as shown in Table 4.

(Comparative Examples 1-7)
Experiments were conducted in the same manner as in the Examples with the blending compositions shown in Table 5, and the evaluation results shown in Table 5 were obtained. The evaluation results are as shown in the table. In some samples, the base material was weakened by overfilling with a diene polymer having a hydroxyl group at the end or its hydrogenated product, and the coating film peeled off at the interface between the base material and the coating film. However, the substrate destruction phenomenon was confirmed, in which the coating film was peeled off when the substrate was destroyed.

  The propylene-based resin composition of the present invention has an excellent balance of strength such as impact strength and flexural rigidity, and can adhere a coating film without applying a solvent primer. It is possible to realize coating adhesion with the organic solvent, and it is possible to reduce the amount of organic solvent due to the paint solvent as well as the organic solvent due to the primer. As a molding material for various industrial parts such as TV case, refrigerator outer plate, washing machine outer plate, bathroom / toiletries such as toilet seat lid and bathtub, etc. It has sufficient performance for practical use and is very useful industrially.

Claims (5)

The following components (a), (b) and (c) are essential components, and the melt flow rate (JIS K7210, temperature 230 ° C., load 21.18 N, hereinafter referred to as MFR) is 0.1 to 100 g / 10 min. The oxygen atom concentration with respect to carbon atoms measured by X-ray photoelectron spectroscopy (XPS / ESCA) on the surface of the molded body obtained from the resin composition is 0.2-2% A propylene-based resin composition having an excellent balance of conductivity, paintability, and physical properties.
Component (a) A propylene homopolymer portion having an MFR of 50 to 400 g / 10 min, an isotactic pentad fraction of 0.98 or more, a propylene content of 50 to 85 wt%, and a glass transition temperature of −40 ° C. Hereinafter, a propylene / ethylene block copolymer having an intrinsic viscosity [η] measured by a cross-fractionation chromatograph of 5 to 9 dl / g and a propylene / ethylene random copolymer portion having an MFR of 25 to 80 g / 10 min. 100 parts by weight of component (b) diene polymer having a hydroxyl group at the terminal or hydrogenated product 0.1 to 15 parts by weight of component (c) particle size 10 to 100 nm, DBP absorption 50 to 600 ml / 100 g, specific surface area 80 to 1500 m ² / g of conductive carbon 1-40 parts by weight The propylene-based resin composition according to claim 1, wherein the volume resistivity value is 10 ⁸ Ωcm or less. Bending elastic modulus (JIS K7203) is 1400 MPa or more, bending strength (JIS K7203) is 20 MPa or more, Izod impact strength (JIS K7110) measured at 23 ° C. and −30 ° C. is 200 and 40 J / m or more, load The propylene-based resin composition according to claim 1 or 2, wherein the deflection temperature (JIS K7207) is 100 ° C or higher under the condition of 4.6 kgf / cm ² .   It uses the propylene-based resin composition according to any one of claims 1 to 3, and is formed by a molding method selected from the group consisting of injection molding, compression molding, injection compression molding, hollow molding, and extrusion molding. A molded product of a propylene-based resin composition to be shaped.   The molded product of the propylene-based resin composition according to claim 4, wherein the coating adhesion rate of the paint directly applied to the surface of the molded product is 100% in terms of the residual rate of the grid pattern in the grid pattern peel test.