JPH0912832A - Coatable propylene resin composition - Google Patents

Abstract

PURPOSE: To obtain a coatable propylene resin composition having improved low-temperature coatability and moldability and improved rigidity and impact strength by mixing two specified C3 H6 /C2 H4 copolymers with a C2 H4 /C4 H8 -1 copolymer rubber, a diene polymer, a filler and a phosphorus oxyacid compound. CONSTITUTION: This coatable propylene resin composition comprises 100 pts.wt. C3 H6 /C2 H4 block copolymer containing a crystalline PP part and a C2 H4 /C3 H6 random copolymer part 5-40 pts.wt. modified C3 H6 homopolymer prepared by grafting 3-25wt.%, based on the entire component, maleic anhydride or a hydroxy maleic anhydride derivative of the formula (wherein R is a 1-4C alkylene) onto a C3 H6 polymer or modified C3 H6 /C2 H4 block or random copolymer prepared by the same grafting, 10-80 pts.wt. C2 H4 /C4 H8 -1 copolymer rubber having a C4 H8 -1 content of 25-40wt.%, a density of 0.87 or below and an MFR of 10 or below, 5-80 pts.wt. at least one talc, mica or fibrous filler having a length of 15μm or below, a mean particle diameter of 1.5-6μm and an average aspect ratio of 5 or above, 0.05-4 pts.wt. phosphorus oxyacid compound and 0-10 pts.wt. hydroxyl-terminated diene polymer or a product of hydrogenation thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel propylene-based resin composition for coating, which has excellent paintability, adhesiveness and printability. The present invention relates to a propylene-based resin composition for coating, which has a high mechanical strength balance (rigidity and impact resistance) and good moldability while having printability and is suitable as a material for various industrial parts.

[0002]

2. Description of the Related Art Conventionally, propylene-based resin materials for various industrial parts are often put to practical use after being wholly or partly painted. However, since these propylene-based resin materials do not have polar groups in the structure of the materials themselves, it is difficult to obtain a practical level of paint adhesion strength when the paint is directly applied. Therefore, in many cases, such a propylene-based resin material has improved paint adhesion performance by subjecting the surface of a preformed material to TCE (trichloroethane) degreasing treatment in advance and applying a primer or plasma treatment. I was letting it.

[0003]

However, such a coating method has conventionally had the following problems. First, in the TCE (trichloroethane) degreasing process, the use of TCE (trichloroethane) has been banned since 1995 due to the conservation of the global environment under the Montreal Protocol. In addition, the primer coating method has a drawback that the coating cost is high because an expensive primer must be used and the number of coating steps is large, and in addition to that, the solvent in the primer is volatilized. Since it was necessary to do so, there was a risk of fire and there was a problem with safety.

On the other hand, in the plasma processing method, since a high vacuum condition is required, it is necessary to install an expensive apparatus, and the batch method cannot avoid an increase in cost. . Furthermore, recently, molded products with complicated shapes have been required, but it is difficult to perform uniform plasma treatment on molded products with such complicated shapes, and the adhesion of paint when contacting foreign matter To decrease
It was very inconvenient to handle, because the coating performance could vary. Therefore, if the steps of TCE (trichloroethane) degreasing treatment, primer coating, and plasma treatment in the coating of propylene-based resin molded products can be omitted, the coating process can be simplified, the working environment improved, and the cost reduced. Therefore, many studies have been conducted so far so as to omit these steps.

For example, a resin composition containing a polypropylene modified with a hydroxyl group (Japanese Patent Publication No. 5-64660), a resin composition containing an unsaturated carboxylic acid graft polypropylene (Japanese Patent Application Laid-Open No. 5-59231), an ethylene-based elastomer, and A resin composition containing polypropylene to which a charging agent is added (JP-A-6-9835) has been proposed. However, molded articles of these compositions do not always have sufficient paint adhesion strength when the paint is directly applied, and when a high degree of mechanical strength balance, especially high rigidity and impact resistance, is required at the same time, it is practically used. In order to obtain a paint adhesion strength at a level, either TCE (trichloroethane) degreasing treatment or primer treatment was practically necessary.

[0006] Further, the paint adhesion strength when the paints of molded articles of these compositions are directly applied is remarkably lowered depending on the kind of the paint, and the tendency is strong especially for melamine-based paints, and the paints of a practical level. It has been difficult to achieve both good adhesion strength, high balance of mechanical strength (high rigidity and low temperature impact strength), and good moldability. Therefore, the present inventors previously proposed a propylene resin composition containing a specific elastomer component and a modified propylene polymer together with a filler (see Japanese Patent Application No. 6-178944), and the coating baking temperature is relatively low. Despite the difficult conditions of 140 ° C. and the use of a melamine-based paint, which is usually difficult to obtain a high paint adhesion strength, we succeeded in developing a practical level of paint adhesion strength with a high balance of physical properties and processability.

However, recently, from the viewpoint of energy saving and cost reduction, further lowering of paint baking temperature and shortening of baking time are being demanded, specifically, 130 ° C.,
Sufficient paint adhesion strength is required under baking conditions of about 15 minutes. On the other hand, in the case of molded articles such as the above-mentioned various compositions, when a coating (particularly a melamine-based coating) is directly applied, baking at 130 ° C. (15 minutes) gives a practical level of coating adhesion strength. It was difficult.

[0008]

[Means for Solving the Problems]

[Summary of the Invention] The present inventors have conducted extensive studies in order to achieve the objects such as simplification of the coating process and expression of practical paint adhesion strength even at a low paint baking temperature. Despite the fact that a molded article molded using a specific propylene-based resin composition was directly coated with the paint and baked at 130 ° C. for 15 minutes, it has practically sufficient paint adhesion strength and is highly mechanical. The present invention has been completed by finding that they have strength balance and molding processability.

That is, the propylene resin composition for coating of the present invention is characterized by comprising the following components (a) to (f). Component (a): Propylene / ethylene block copolymer containing crystalline polypropylene part (A unit part) and ethylene / propylene random copolymerization part (B part): 100 parts by weight Component (b): Butene- 1 ethylene-butene-1 binary copolymer rubber having a content of 25 to 40% by weight, a density of 0.87 g / cm ³ or less and a melt flow rate (230 ° C., 2.16 kg) of 10 g / 10 minutes or less: 10 -80 parts by weight Component (c): Substantially the entire length is 15 μm or less, the average particle size is 1.5 to 6 μm, and the average aspect ratio is talc of 5 or more, the average particle size is 8 to 100 μm, and Mica having an average aspect ratio of 10 or more, or at least one filler selected from fibrous fillers having an average diameter of 6 μm or less and an average aspect ratio of 5 or more: 5 to 80 parts by weight Component (d) A modified propylene homopolymer or the same propylene in which maleic anhydride or a maleic anhydride derivative containing a hydroxyl group represented by the following chemical formula is grafted onto a propylene-based polymer in an amount of 3 to 25% by weight based on the total amount of the component (d). Block or random copolymer of ethylene and ethylene: 5 to 40 parts by weight

[0010]

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(In the formula, R represents an alkylene group having 1 to 4 carbon atoms.) Component (e): phosphorus oxyacid compound: 0.05 to 4 parts by weight Component (f): diene polymer having a hydroxyl group at the terminal Or hydrogenated product thereof: 0 to 10 parts by weight

[Detailed Description of the Invention] [I] Propylene Resin Composition (1) Constituent Composition (a) Component (a): Propylene-Ethylene Block Copolymer The propylene resin composition for coating of the present invention The propylene / ethylene block copolymer of the above component (a) constituting
A propylene / ethylene block copolymer containing a crystalline polypropylene portion (A unit portion) and an ethylene / propylene random copolymer portion (B unit portion), wherein
The unit part is obtained by homopolymerization of propylene, and the B unit part is obtained by random copolymerization of propylene and ethylene. Where A
The unit is preferably 60 to 95% by weight in the propylene / ethylene block copolymer, especially in terms of heat resistance and rigidity.
It is more preferable to occupy a proportion of 75 to 94% by weight, and the density thereof is also 0.
9070 g / cm ³ or more is preferable, 0.9086 g /
More preferably, it is at least cm ³ . Further, the B unit part occupies a proportion of preferably 5 to 40% by weight, more preferably 6 to 25% by weight in the propylene / ethylene block copolymer, particularly from the viewpoint of paint adhesion and impact resistance. The content of ethylene is preferably 20 to 80% by weight, more preferably 25 to 50% by weight, from the viewpoints of paint adhesion and impact resistance.

The melt flow rate (hereinafter simply referred to as "MFR") of the whole propylene / ethylene block copolymer is 5 to 100 g / 10 minutes, particularly 10 to 50 g /.
It is preferably 10 minutes, and the weight average molecular weight / number average molecular weight (Mw / Mn) of the entire propylene / ethylene block copolymer is 7 in terms of moldability and appearance of the molded product.
Above, especially above 8 are preferable. The content of the B unit of the propylene / ethylene block copolymer is 2
The sample (g) was immersed in 300 g of boiling xylene for 20 minutes to dissolve it, then cooled to room temperature, and the solid phase thus deposited was filtered with a glass filter and dried. is there. Also, the above weight average molecular weight /
The value of number average molecular weight (Mw / Mn) is measured by gel permeation chromatography (GPC), the value of ethylene content is determined by infrared spectrum analysis method, etc., and the value of MFR is JIS-K7210 (230).
C., 2.16 kg).

Manufacture The propylene / ethylene block copolymer as the component (a) is produced by slurry polymerization, gas phase polymerization or liquid phase bulk polymerization using a highly stereoregular polymerization catalyst. As a polymerization method for producing the propylene / ethylene block copolymer, either batch polymerization or continuous polymerization can be adopted. When producing this propylene / ethylene block copolymer, either part may be polymerized first, but first, the crystalline polypropylene part (A unit part) is formed by homopolymerization of propylene, and then A product in which an ethylene / propylene random copolymerized portion (B unit portion) is formed by random copolymerization of propylene and ethylene is preferable in terms of quality. As a specific method, titanium tetrachloride in magnesium chloride, a solid component formed by contacting an organic acid halide and an organic silicon compound, using a catalyst in which an organoaluminum compound component is combined, to carry out homopolymerization of propylene, Then, it can be produced by carrying out random copolymerization of propylene and ethylene. Further, the propylene / ethylene block copolymer contains other unsaturated compounds, for example, α-olefin such as butene-1, vinyl ester such as vinyl acetate, etc. within a range not impairing the effects of the present invention. It may be a copolymer of the original or higher or a mixture thereof.

Blending ratio Each of the components (a) to (f) to be blended in the propylene resin composition for coating of the present invention is 100 parts by weight of the propylene / ethylene block copolymer of the component (a). It is compounded based on. Further, the blending ratio of each component below the component (b) is as described later.

(B) Component (b): ethylene / butene-1 binary copolymer rubber component (EBM) The above-mentioned component (b), ethylene / butene-12, which constitutes the propylene resin composition for coating of the present invention. The original copolymer rubber component has a butene-1 content of 25 to 40% by weight, preferably 30.
-40% by weight, particularly preferably 30-36% by weight, density 0.87 g / cm ³ or less, preferably 0.84-0.8.
7 g / cm ³ , particularly preferably 0.85 to 0.87 g /
cm ³ and MFR (230 ° C, 2.16kg) 10g
/ 10 min or less, preferably 0.2 to 8 g / 10 min of ethylene / butene-1 binary copolymer rubber (EBM). Ethylene / butene-1 binary copolymer rubber (E
BM) is unsuitable because it has a poor balance of paint adhesion and mechanical strength. Here, measurement with a differential calorimeter (hereinafter referred to as DSC, for example, RDC-220 manufactured by Seiko Denshi Kogyo) (20
(° C / min) melting peak temperature of 35 ° C or lower,
Conventional crystallinity measured by X-ray method (5-12%)
A much lower amount of 1% or less is particularly preferable in that the paint adhesion strength and impact strength of the composition can be improved. Conventionally, ethylene / butene-1 binary copolymer rubber (EB
In M), those having a butene-1 content exceeding 25% by weight, those having a density of 0.87 g / cm ³ or less, that is, those having low crystallinity, and those having a melting temperature of 35 ° C. or less and crystals It was extremely difficult (particularly in the form of pellets) to produce a polymer having a degree of chemical conversion of 1% or less, but it can be produced by improving the polymerization catalyst, the polymerization process and the like, and the effects of the present invention can be exhibited. It was The butene-1 content is a value measured by a conventional method such as an infrared spectrum analysis method. These ethylene / butene-1 binary copolymer rubbers are
It does not matter whether it is in the form of a bale, pellet, flake, crumb, or the like, and its manufacturing method is not particularly limited.

Blending Ratio The ethylene / butene-1 binary copolymer rubber (EB) as the component (b) to be blended in the propylene resin composition for coating of the present invention.
The mixing ratio of M) is 10 to 80 parts by weight, preferably 30 to 80 parts by weight, relative to 100 parts by weight of the above component (a).
Particularly preferably, 40 to 80 parts by weight is blended. If the blending ratio is less than the above range, the paint adhesion performance and impact strength will be poor, and if the blending ratio exceeds the above range, the appearance, heat resistance rigidity and dimensional stability of the molded product will be poor, which is not practical.

(C) Component (c): Filler Component constituting the propylene resin composition for coating of the present invention
The filler component (c) has a substantially total length of 15 μm.
The following is preferably 10 μm or less, the average particle diameter is 1.5 to 6 μm, preferably 1.5 to 4 μm, and the average aspect ratio is 5 or more, preferably 6 or more talc, and the average particle diameter is 8 to 100 μm. And the average aspect ratio is 10
As described above, mica of 15 or more, or at least one selected from fibrous fillers having an average diameter of 6 μm or less, preferably 0.1 to 5 μm and an average aspect ratio of 5 or more. If the composition is out of the above range, the composition has a poor mechanical strength balance and is not suitable.

Of these, the above talc is particularly preferable because it can further enhance the balance between paint adhesion strength and mechanical strength. Here, "substantially" the length of talc means that most talc particles are in this range. Talc is produced, for example, by crushing rough talc with an impact type crusher or a micron type crusher, further finely crushing it with a micron mill or jet type crusher, and then classifying and adjusting it with a cyclone or a micron separator. Rough stones are preferred from China because they contain less metallic impurities. Mica, white mica, gold mica, there are different types of black mica and the manufacturing method, but are not particularly limited thereto, preferably white mica and gold mica, particularly wet grinding and wet classification white mica and Gold mica is preferred. Examples of the fibrous filler include glass fiber, carbon fiber, aluminum borate fiber, potassium titanate fiber, basic magnesium sulfate fiber, calcium carbonate fiber and the like. Among these, preferred are those having an average diameter of 0.2 to 5 μm and an average aspect ratio of 10 or more.

Here, the average particle size is a value measured by using a laser light scattering type particle size distribution meter. As such a measuring device, for example, LA-500 manufactured by Horiba Ltd.
A mold is desirable because of its excellent measurement accuracy. Also, the diameter,
The length and the aspect ratio are values measured by a microscope or the like. These fillers include surfactants, coupling agents,
It may be surface-treated with metal soap or the like. The surface-treated filler is effective in further improving paint adhesion, mechanical strength, moldability, appearance of molded products, dimensional stability, and the like.

Blending Ratio The blending ratio of the component (c) filler to be blended in the propylene resin composition for coating of the present invention is such that the component (a) is 100%.
5 to 80 parts by weight, preferably 5 to 60 parts by weight
Parts by weight, particularly preferably 10 to 60 parts by weight, are blended.
If the compounding ratio is less than the above range, the heat resistance rigidity and dimensional stability are poor, and if the compounding ratio exceeds the above range, the appearance and impact strength of the molded product are poor, which is not practical. (d) Component (d): Modified propylene-based polymer Component constituting the propylene-based resin composition for coating of the present invention
In the modified propylene-based polymer (d), maleic anhydride or a hydroxyl group-containing maleic anhydride derivative represented by the following chemical formula is contained in the propylene-based polymer in an amount of 3 to 2 of the total amount of the component (d).
A modified propylene homopolymer, a modified propylene / ethylene block copolymer or a modified propylene / ethylene random copolymer grafted at a ratio of 5% by weight, preferably 5 to 20% by weight. Grafting is carried out at least at one end of the main chain of the propylene-based polymer and / or in a form in which a graft monomer is bonded to the main chain.

[0022]

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(In the formula, R represents an alkylene group having 1 to 4 carbon atoms.) Here, the number average molecular weight of the main chain portion of the propylene-based polymer is preferably 1,000 to 20,000, and particularly preferably 3, 000 to 15,000 is preferable. The method for producing the modified propylene-based polymer is not particularly limited. For example,
Examples include a method in which a propylene-based polymer is thermally oxidized in advance and then a functional group is grafted, or a method in which the propylene-based polymer is grafted in an extruder or a solution.

Blending Ratio The blending ratio of the modified propylene-based polymer of the component (d) to be blended in the propylene-based resin composition for coating of the present invention is 5 to 40 with respect to 100 parts by weight of the above-mentioned component (a). Part by weight, preferably 10 to 40 parts by weight, particularly preferably 10 to 35 parts by weight. If the blending ratio is less than the above range, the paint adhesion performance is poor, and if it exceeds the above range, the mechanical strength balance is poor, which is not practical.

(E) Component (e): Phosphorus oxyacid compound Component constituting the propylene resin composition for coating of the present invention
The phosphorus oxyacid compound component (e) is a compound having a structure in which an oxygen atom is directly bonded to a phosphorus atom (phosphorus oxyacid structure), and among these, those having a phosphoric acid ester structure are preferable, An acidic phosphoric acid ester derivative is preferred. As a specific example, phosphoric acid monobutyl ester,
Phosphoric acid dibutyl ester, phosphoric acid mono (2-ethylhexyl) ester, phosphoric acid di (2-ethylhexyl) ester, phosphoric acid mono (isodecyl) ester, phosphoric acid di (isodecyl) ester, phosphoric acid mono (lauryl) ester, phosphoric acid di (lauryl) ester, Examples thereof include phosphoric acid mono (tridecyl) ester, phosphoric acid di (tridecyl) ester, phosphoric acid mono (nolylphenoxyethyl) ester, and the like.

Blending Ratio The blending ratio of the phosphorus oxyacid compound component of component (e) to be blended in the propylene resin composition for coating of the present invention is 0.05 based on 100 parts by weight of the above component (a). -5 parts by weight, preferably 0.1-5 parts by weight, particularly preferably 0.5-2
It is blended by weight. If the blending ratio is less than the above range, the paint adhesion performance is poor, and if it exceeds the above range, the mechanical strength balance is poor, which is not practical.

(F) Component (f): Diene Polymer In the propylene resin composition for coating of the present invention, the diene polymer of the above component (f), which is optionally used, is
It is a diene polymer having a hydroxyl group at the terminal or a hydrogenated product thereof. Among them, examples of the diene polymer having a hydroxyl group at the terminal include polyhydroxy polybutadiene. Specifically, it has at least one hydroxyl group at the terminal and has a molecular weight of 200 to 100,000, preferably 500 to 50,000, particularly preferably 800 to 10,
000, liquid, semi-solid and solid polymers at ambient temperature are included. The average number of hydroxyl groups per molecule is generally 1 to 10,
Particularly, those having 1.5 to 5 are preferable, and the hydroxyl value is generally 1
5-250, preferably 25-125 (KOHmg /
Those of g) are preferred.

The diene polymer having a hydroxyl group at the terminal is
A known method using 1,3-diene as a raw material, for example,
It is produced by a radical polymerization method, an anionic polymerization method or the like. Specifically, for example, Japanese Patent Laid-Open No. 51-7139.
The method described in Japanese Patent No. 1 can be mentioned. When this product is produced by radical polymerization, it can be obtained by polymerizing a diene monomer using hydrogen peroxide as a polymerization initiator. In the case of producing by anionic polymerization, according to a known method, a conjugated diene is polymerized with an anionic polymerization catalyst, for example, an alkali metal or an organic alkali metal compound, and at least one end thereof has an alkali metal. The living polymer having a bonded structure may be reacted with, for example, a monoepoxy compound, formaldehyde, acetaldehyde, acetone, halogenoalkylene oxide, polyepoxide, or the like. At least one type of conjugated diene monomer is used as a raw material monomer for these polymers. As the conjugated diene monomer, 1,3-butadiene, 1,
3-pentadiene, isoprene, chloroprene, 2,3
-Dimethyl-1,3-butadiene, 1-phenyl-1,
3-butadiene etc. can be mentioned.

As the hydrogenated product of the diene polymer having a hydroxyl group at the terminal, the diene polymer having a hydroxyl group at the terminal may be prepared by a conventional method, for example, JP-A-51-7.
It is obtained by adding hydrogen by the method described in Japanese Patent No. 1391. The degree of hydrogenation may be such that the double bonds contained in the polymer are wholly or partially hydrogenated, but particularly, the iodine value is usually 0 to 20,
Particularly, those of 0 to 5 (g / 100g) are preferable. These diene polymers having a hydroxyl group at the terminal or hydrogenated products thereof can be used alone or as a mixture of two or more.

Blending Ratio The blending ratio of the diene polymer of the component (f) to be blended in the propylene resin composition for coating of the present invention is the above component (a).
The amount is 0 to 10 parts by weight, preferably 0.5 to 10 parts by weight, and particularly preferably 1 to 5 parts by weight with respect to 100 parts by weight. If the blending ratio is less than the above range, the paint adhesion performance is poor, and if it exceeds the above range, the mechanical strength balance is poor, which is not practical.

(G) Component (g): Other compounding components (optional components) In the propylene resin composition for coating of the present invention, the effect of the present invention is not significantly impaired, or the performance is further improved. In order to measure, in addition to the essential components of the above components (a) to (f), the following optional additives and compounding material components can be blended. Specifically, pigments for coloring, antioxidants, antistatic agents, flame retardants, dispersants, light stabilizers, nucleating agents, various resins other than the above components (a) to (f), various rubbers, Examples include compounding materials such as various fillers. Among these, ethylene / propylene binary copolymer rubber (EPM) and ethylene / propylene / diene ternary copolymer rubber (EPDM) are effective for improving paint adhesion strength, impact strength and economic efficiency.

[II] Production of Propylene Resin Composition (1) Kneading / Granulation The above components (a) to (f), and optionally component (g) are blended in the above blending ratio, and a uniaxial extruder, The propylene-based resin composition for coating of the present invention can be obtained by kneading and granulating using a normal kneading machine such as a twin-screw extruder, a Banbury mixer, a roll mixer, a Brabender plastograph, and a kneader. In this case, it is preferable to select a kneading / granulating method capable of improving the dispersion of each component, and the kneading / granulating is usually performed using a twin-screw extruder. In this kneading / granulation, the above components (a) to (f), and optionally a mixture of the components (g) may be kneaded at the same time, and each component is divided in order to improve the performance, for example, First, the component (a)
It is also possible to knead a part or all of the component (b) and the component (b), and then knead and granulate the remaining components.

(2) Molding The propylene resin composition for coating thus obtained is subjected to various molding methods, that is, injection molding, injection compression molding (press injection), compression molding, extrusion molding (sheet molding, Various molded products can be obtained by molding by film molding, blow molding, etc. Among these various molding methods, injection molding (including gas injection molding), injection compression molding (press injection) Preferably.

[III] Uses of Propylene-Based Resin Composition The propylene-based resin composition for coating of the present invention has excellent coatability, specifically, a coating material for molded articles (particularly, generally obtains high coating material adhesion performance). It is difficult to apply melamine-based paint directly, and when using a melamine-based paint, baking at a temperature of 130 ° C., which is lower than conventional ones, makes it possible to obtain practically sufficient paint adhesion performance. Since it has a high degree of mechanical strength balance, good molding processability, and good adhesiveness and printability, it has sufficient performance for practical use as a molding material for various industrial parts.

[0035]

EXAMPLES In order to describe the propylene resin composition for coating of the present invention in more detail, experimental examples will be shown below, but the present invention is not limited to these experimental examples. Absent. [I] Raw material (1) Component (a) ... All are in powder form a-1: 91% by weight of crystalline polypropylene part (A unit part) having a density of 0.9091 g / cm ³ , ethylene having an ethylene content of 39% by weight. -Propylene random copolymerization part (B unit part) each containing 9% by weight, the total polymerization MFR of component (a) (230 ° C, 2.16 kg) was 11 g / 10.
Propylene / ethylene block copolymer having a total Mw / Mn of 8.4 of component (a) a-2: 92% by weight of a crystalline polypropylene portion (unit A) having a density of 0.9093 g / cm ³ . It contains 8% by weight of ethylene / propylene random copolymerization part (B unit) having an ethylene content of 40% by weight, and the total polymerization MFR (230 ° C., 2.16 kg) of component (a) is 20 g / 10.
Propylene / ethylene block copolymer having a total Mw / Mn of 8.2 of component (a) (2) Component (b) ... All in pellet form b-1: Butene-1 content 33% by weight, MFR ( 230
℃, 2.16kg) 1.1g / 10min, density 0.86g
Ethylene / butene-1 binary copolymer rubber (EBM) having a melting point / cm ³ , a DSC melting peak temperature of 26 ° C. and a crystallinity of 1% or less by the X-ray method (almost not recognized) b-2: butene-1 content 32 % By weight, MFR (230
℃, 2.16kg) 6.3g / 10 minutes, density 0.86g
Ethylene / butene-1 binary copolymer rubber (EBM) having a melting point / cm ³ , a DSC melting peak temperature of 25 ° C., and a crystallinity of 1% or less by the X-ray method (almost unrecognized).

(3) Component (c) ... All are in powder form c-1: substantially the entire length is 10 μm or less,
Talc having an average particle size of 2.7 μm and an average aspect ratio of 6 c-2: basic magnesium sulfate fiber having an average diameter of 0.4 μm and an average aspect ratio of 33 (4) Component (d) ... flaky d- 1: MFR (230 ° C, 2.16kg) is 60g /
The propylene / ethylene random copolymer having a number average molecular weight of 6,800 and an ethylene content of 4% by weight is thermally oxidized for 10 minutes, and the component ( d) A modified propylene polymer obtained by grafting a maleic anhydride group at a ratio of 10% by weight of the whole and further modifying the maleic anhydride group with ethanolamine (5) Component (e) ... Liquid e-1: phosphoric acid Mono (2-ethylhexyl)) ester (6) Component (f) ... flake f-1: iodine value 1.3 (g / 10 minutes), hydroxyl value 8
5.6 (KOH mg / cm ³ diene polymer hydrogenated product

[II] Evaluation Method Evaluation was carried out by the following method. [Coating] (Paint) A one-component organic solvent-based melamine cross-linking paint was used. (Coating method) The molded flat plate was spray-coated with an air spray gun so as to have a coating film thickness of about 25 µm without any pretreatment. (Baking treatment) The coated flat plate was baked and dried at 130 ° C for 15 minutes (data for baking and drying at 140 ° C for 20 minutes was also added to Comparative Example 1). Then, it was left at room temperature for 48 hours.

[Evaluation of Coating Adhesion] (Initial Cross Cut Test) A single-edged razor was used to draw 11 parallel vertical and horizontal parallel lines at 2 mm intervals on the surface of a baked test piece, and the cross cut was 100 I made it individually. Cellophane adhesive tape (JIS-Z1522) was sufficiently pressure-bonded on it, kept at about 30 degrees with the coating surface, and the work of peeling off at once in front was repeated 5 times, and the state of the part surrounded by the grid was observed. The number of grids that did not peel was recorded. (Heat-resistant cross-cut test) First, a baked test piece was immersed in warm water at 40 ° C. for 240 hours, and then, 24
Left at room temperature for hours. Then, using a single-edged razor, 11 vertical and horizontal parallel lines were drawn at 2 mm intervals to make 100 squares. Cellophane adhesive tape (JI
S-Z1522) is sufficiently pressure-bonded, is kept at about 30 degrees with the coating surface, and is peeled off all at once in front, repeated 5 times. Recorded the number of. At this time, the test piece without peeling was further repeated 5 times. Usually, it is at a practical level if there is no peeling in the first five times.

[Mechanical Strength Evaluation] (Flexural Elastic Modulus) The mechanical strength was measured according to JIS-K7203. The measurement temperature is 23 ° C. This value is also a measure of heat resistance. Particularly, those having a pressure of 1,400 MPa or more are useful for various industrial parts, and those having a pressure of 1,500 MPa or more are particularly useful. (Izod impact strength) Measured according to JIS-K7110 (with notch). The measurement temperature is -30C.
Particularly, those of 5 KJ / m ² or more are useful for various industrial parts, and those of 6 KJ / m ² or more are particularly useful.

[Moldability] (spiral (flow) length, MFR) As a measure of moldability, a screw in-line injection molding machine was used.
Spiral mold (flow cross-sectional shape: top side = 13 mm, bottom side = 14.5 mm, thickness = 3 mm, gate = direct)
The flow length at was measured. The molding conditions at this time were molding temperature = 220 ° C., mold temperature = 20 ° C., screw rotation speed 70 rpm, and injection pressure = 600 kg / cm ² .
Particularly, those having a thickness of 1,200 mm or more have good moldability. For some samples, the MFR
It measured based on S-K7210 (230 degreeC, 2.16 kg). In this case, those having an MFR of 8 g / 10 minutes or more have good moldability, and those having an MFR of 12 g / 10 minutes or more are particularly good.

[Lightness] (Density) Measured at 23 ° C. according to JIS-K7112. Especially 1.05 g / cm ³ or less, especially 1.03 g / cm ³
Those having a cm ³ or less are preferable because they have excellent strength despite their light weight.

[III] Experimental Examples Examples 1 to 7 and Comparative Examples 1 to 7 Component (a), Component (b), Component (c), Component (d), Component
(e) and component (f) were blended in the proportions shown in Table 1, and tetrakis [methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane was added as a component. (a) to component (e) or component (a) to component (f) was added in an amount of 0.1 part by weight in terms of a total amount of 100 parts by weight, and these were sufficiently mixed with a high-speed mixer (however, 1
When the component c-2 was used in the filler of (1), the fiber portion was excluded and it was fed midway in the latter stage extruder. ).
After that, high-speed twin-screw extruder (KCM) manufactured by Kobe Steel, Ltd.
Type), kneading and granulating under a temperature condition of 210 ° C.,
The obtained pellets were supplied to the above injection molding machine to mold a coating sheet test piece and a physical property measurement test piece for evaluation. Table 2 shows the evaluation results. As shown in Tables 1 and 2, each of the resin compositions having the compositions shown in Examples 1 to 7 had good paint adhesion performance, mechanical strength balance, and moldability, and was lightweight. . on the other hand,
Those shown in Comparative Examples 1 to 7 had a poor balance of these performances.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

EFFECTS OF THE INVENTION The propylene resin composition for coating of the present invention has excellent coating properties, specifically, a coating (particularly less than 150 ° C.) is generally applied to a molded product without TCE pretreatment or primer coating. In baking and drying with melamine, it is difficult to obtain high paint adhesion performance directly, and practically sufficient paint adhesion performance is achieved even under efficient baking and drying conditions at 130 ° C for about 15 minutes. In addition, it has a high mechanical strength balance (especially high rigidity and low temperature impact strength) and excellent molding processability.
Since it is lightweight and has excellent dimensional stability, it can be expected to be applied as various industrial parts and is an extremely important industrial material.

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Claims (6)

[Claims] 1. A propylene resin composition for coating, comprising the following components (a) to (f): Component (a): Propylene / ethylene block copolymer containing crystalline polypropylene part (A unit part) and ethylene / propylene random copolymerization part (B part): 100 parts by weight Component (b): Butene- 1 ethylene-butene-1 binary copolymer rubber having a content of 25 to 40% by weight, a density of 0.87 g / cm ³ or less and a melt flow rate (230 ° C., 2.16 kg) of 10 g / 10 minutes or less: 10 -80 parts by weight Component (c): Substantially the entire length is 15 μm or less, the average particle size is 1.5 to 6 μm, and the average aspect ratio is talc of 5 or more, the average particle size is 8 to 100 μm, and Mica having an average aspect ratio of 10 or more, or at least one filler selected from fibrous fillers having an average diameter of 6 μm or less and an average aspect ratio of 5 or more: 5 to 80 parts by weight Component (d) A modified propylene homopolymer or the same propylene in which maleic anhydride or a maleic anhydride derivative containing a hydroxyl group represented by the following chemical formula is grafted onto a propylene-based polymer in an amount of 3 to 25% by weight based on the total amount of the component (d). Block or random copolymer of ethylene and ethylene: 5 to 40 parts by weight (In the formula, R represents an alkylene group having 1 to 4 carbon atoms.) Component (e): Phosphorus oxyacid compound: 0.05 to 4 parts by weight Component (f): Diene polymer having a hydroxyl group at the terminal or hydrogen thereof Additives: 0-10 parts by weight 2. The component (a), wherein the A unit accounts for 60 to 95% by weight of the block copolymer and has a density of 0.9070 g.
/ Cm ³ or more, and the B unit is 5 of the block copolymer.
-40% by weight, its ethylene content is 20-80% by weight, and the melt flow rate (230 ° C, 2.16 kg) of the entire component (a) is 5-100 g / 10 minutes. ) The total weight average molecular weight / number average molecular weight is 7
The propylene-based resin composition for coating according to claim 1, which is the block copolymer described above. 3. An ethylene / butene-1 binary copolymer rubber (EBM) as the component (b) is melted (peak) by a differential calorimeter.
The propylene-based resin composition for coating according to claim 1, which has a temperature of 35 ° C. or lower. 4. The component (d) has a number average molecular weight obtained by grafting a hydroxyl group-containing maleic anhydride derivative represented by the following chemical formula onto a propylene polymer at a ratio of 5 to 20% by weight based on the total weight of the component (c). The propylene resin composition for coating according to claim 1, which is a modified propylene homopolymer of 4,000 to 13,000 or a block or random copolymer of the same propylene and ethylene. Embedded image 5. The propylene resin composition for coating according to claim 1, wherein the component (e) is an acid phosphate derivative. 6. The resin composition has a flexural modulus of 1,400 MP.
a or more, -30 ° C. Izod impact strength 5 KJ / m ² or more, spiral length 1,200 mm or more, and density 1.
The propylene resin composition for coating according to claim 1, which has a performance of not more than 05 g / cm ³ .