JPH0841226A - Method for treating surface of polypropylene resin composition moled product, method for coating and coated polypropylene resin molded product - Google Patents

Abstract

PURPOSE:To treat the surface of the molded prduct so as to improve the coating suitability, adhesion and printability by irradiating the molded product of a specific PP resin composition with UV rays. CONSTITUTION:The method for treating the surface of the polypropylene resin composition comprises irradiating the molded product of a PP resin composition comprising (A) 15-92wt.% of crystalline ethylene-propylene block copolymer [e.g. the block copolymer having crystalline PP parts and ethylene-propylene random copolymer parts, the content of the ethylene-propylene random copolymer part being 5-20wt.%]. (B) 5-40wt.% of an ethylene-propylene copolymer rubber [e.g. the rubber having a Mooney viscosity (ML1+4, 100 deg.C) of 10-100 and a propylene content of 20-70wt.%), (C) 1-15wt.% of an OH group-having propylene oligomer (e.g. having a number-average mol. wt. of 2000-20000 and an OH value of 10-80), and (D) 2-30wt.% of an inorganic filler (e.g. talc having an average particle diameter of <=3nm) with <=300nm UV rays.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment method for a polypropylene resin composition molded article, a coating method for the molded article, and a resin coated molded article.

[0002]

2. Description of the Related Art Since polypropylene resins are non-polar, it is difficult to satisfactorily coat, bond, print, etc. their molded products. Therefore, various measures have been conventionally performed to favorably coat the surface of the molded product.

For example, as a method for further improving the compatibility between a polypropylene resin molded product (hereinafter sometimes simply referred to as "molded product") and an adhesive or paint,
There was a method of providing an intermediate layer between them. The intermediate layer is composed of chlorinated polypropylene and toluene,
A medium called a so-called primer has been widely used.

Further, as a surface treatment method for improving the surface of a molded product to a surface suitable for painting, a sandblasting method, a chrome mixed acid treatment method, a flame treatment method, a corona discharge treatment method, a plasma treatment method and the like have been proposed. Was there.

[0005]

However, in the conventional method of providing the intermediate layer, the final product cost is high because the primer itself is expensive and one step is newly added to form the intermediate layer. There was a problem that became. Furthermore, before applying the primer, 1,1,
Steam cleaning with a halogenated hydrocarbon solvent such as 1-trichloroethane is usually carried out.
-The use of trichloroethane is being regulated due to the ozone problem, which is one of the recent global environmental measures.

Further, none of the surface treatment methods such as sandblast treatment, chromium mixed acid treatment, flame treatment, corona discharge treatment and plasma treatment have been able to achieve satisfactory results. Further, for example, in the chromium mixed acid treatment, there is a problem that the waste liquid needs to be made pollution-free.

The present invention has been made in view of the above points. Therefore, the object of the present invention is to solve the above-mentioned problems, and to improve the paintability, adhesiveness and printability of the surface of a polypropylene resin molded article. It is an object of the present invention to provide a surface treatment method which is extremely useful for improving the above-mentioned properties, a coating method using the same, and a coated molded article.

[0008]

In view of such circumstances, the inventors of the present invention have earnestly studied the surface treatment and coating method of a polypropylene-based resin composition molded product, and as a result, a polypropylene-based resin composition molded product of a specific composition. The inventors have found that the surface properties of the molded product are remarkably improved by irradiating the surface with ultraviolet rays having a specific wavelength, and have completed the present invention.

That is, according to the present invention, the crystalline ethylene-propylene block copolymer (A) is 15 to 92% by weight, the ethylene-propylene copolymer rubber (B) is 5 to 40% by weight,
A polypropylene system characterized by irradiating a molded article of a polypropylene resin composition comprising 1 to 15% by weight of a hydroxyl group-containing propylene-based oligomer (C) and 2 to 30% by weight of an inorganic filler (D) with ultraviolet rays of 300 nm or less. The present invention provides a surface treatment method for a resin composition molded article. In addition, the present invention is a crystalline ethylene-propylene block copolymer (A) 15 to 92 wt%, ethylene-propylene copolymer rubber (B) 5 to 40 wt%, hydroxyl group-containing propylene-based oligomer (C) 1 to. After irradiating a molded product of a polypropylene-based resin composition composed of 15% by weight and an inorganic filler (D) of 2 to 30% by weight with ultraviolet rays of 300 nm or less,
It is intended to provide a method for coating a polypropylene-based resin composition molded article, which is characterized by coating with a paint. Furthermore, the present invention provides crystalline ethylene-propylene block copolymer (A) 15 to 92% by weight, ethylene-propylene copolymer rubber (B) 5 to 40% by weight, hydroxyl group-containing propylene-based oligomer (C) 1 to A molded product of a polypropylene resin composition comprising 15% by weight and 2 to 30% by weight of an inorganic filler (D), which is obtained by irradiating the molded product with ultraviolet rays of 300 nm or less and then coating with a paint. A resin-based molded product is provided.

Hereinafter, the present invention will be described specifically. The crystalline ethylene-propylene block copolymer (A) used in the present invention is usually produced by mixing propylene and then a mixture of propylene and ethylene in the presence of a Ziegler-Natta catalyst in combination with titanium trichloride and an alkylaluminum compound. Although it can be obtained by polymerization at a stage, in carrying out the present invention, it is preferable to use a catalyst composed of a complex of titanium trichloride and magnesium, a trialkylaluminum compound and an electron-donating organic compound. The method for producing this catalyst is described in detail, for example, in JP-A-61-218606.

The compounding ratio of the crystalline ethylene-propylene block copolymer (A) in the polypropylene resin composition used in the present invention is 15 to 92% by weight, preferably 25 to 85% by weight. When the blending ratio is less than 15% by weight, the appearance (especially flow mark), rigidity and heat resistance of the obtained molded article deteriorate. On the other hand, when it exceeds 92% by weight, low temperature impact resistance and coating adhesion are deteriorated.

The crystalline ethylene-propylene block copolymer (A) includes a crystalline polypropylene portion and an ethylene-propylene random copolymer portion in which ethylene / propylene = 20/80 to 60/40 (weight ratio). And the intrinsic viscosity of the crystalline polypropylene part [η]
p is 0.8 to 2.0 dl / g, the ratio Q value of molecular weight measured by GPC (weight average molecular weight M _W / number-average molecular weight M _N) is 3.0～5.0,20 ° C. xylene solubles Is 1.5% by weight
Those in which the ethylene-propylene random copolymer part is 5 to 20% by weight of the crystalline ethylene-propylene block copolymer (A) are preferably used below.

The ethylene / propylene random copolymer portion has an ethylene / propylene (weight ratio) of 20/80 to.
It is 60/40, preferably 20/80 to 50/50.

The proportion of the ethylene-propylene random copolymer portion in the crystalline ethylene-propylene block copolymer (A) is 5 to 20% by weight, preferably 7 to 15% by weight.

The intrinsic viscosity [η] p of the crystalline polypropylene part in tetralin at 135 ° C. is 0.8 to 2.0 dl /
It is g.

Further, the crystalline polypropylene portion is replaced with GPC.
In the ratio Q value of the measured molecular weight (weight average molecular weight M _W / number-average molecular weight M _N) is in the range of 3.0 to 5.0.

The 20 ° C. xylene-soluble content of the crystalline polypropylene portion is 1.5% by weight or less, preferably 1.2% by weight.
It is the following.

The ethylene-propylene copolymer rubber (B) of the present invention is usually polymerized in a hydrocarbon solvent in the presence of a catalyst composed of a vanadium compound and an organic aluminum compound. Examples of the vanadium compound include vanadium oxytrichloride, vanadium tetrachloride, and vanadate compounds. Examples of the organic aluminum compound include ethyl aluminum sesquichloride and diethyl aluminum chloride. Examples of the hydrocarbon solvent include hexane and heptane.

Here, "ethylene-propylene copolymer rubber" means a copolymer consisting of ethylene and propylene alone and, if necessary, a copolymer containing these and other comonomer, especially a non-conjugated diene. Also includes. Examples of non-conjugated dienes include dicyclopentadiene, 1,4-hexadiene, cyclooctadiene, vinylnorbornene, and 5
-Ethylidene-2-norbornene and the like are used.

The ethylene-propylene copolymer rubber (B) of the present invention includes those produced by using a titanium-based catalyst composed of a titanium-based compound and an organoaluminum compound, and comprises only ethylene and propylene. It means a copolymer and a copolymer with another comonomer such as a non-conjugated diene.

Two or more of these ethylene-propylene copolymer rubbers are mixed according to their respective purposes such as fluidity of the composition, rigidity, heat resistance, low-temperature impact resistance, appearance of molded articles and coating adhesion. Can be used.

The Mooney viscosity (M) of the ethylene-propylene copolymer rubber (B) of the present invention measured at 100 ° C.
L _{1 + 4} ) is 10 to 100, preferably 20 to 85. The propylene content of the ethylene-propylene copolymer rubber is 20 to 75% by weight.

The ethylene-propylene copolymer rubber preferably has an iodine value of less than 20 when a small amount of non-conjugated diene monomer is copolymerized.

The proportion of the ethylene-propylene copolymer rubber (B) in the polypropylene resin composition used in the present invention is 5 to 40% by weight, preferably 10 to 35% by weight. When the compounding ratio is less than 5% by weight, low temperature impact strength and coating adhesion are lowered, and when it exceeds 40% by weight, rigidity,
Heat resistance and appearance (especially flow marks) deteriorate.

The hydroxyl group-containing propylene-based oligomer (C) used in the present invention is an oligomer containing a hydroxyl group-containing low molecular weight polypropylene as a main component. The polypropylene is selected from homopolypropylene, propylene-α-olefin random copolymer containing 0.5 to 8% by weight of ethylene or α-olefin having 4 to 6 carbon atoms, and the propylene-ethylene block copolymer. Those that are preferred are. Specific examples of the hydroxyl group-containing propylene-based oligomer include low molecular weight polypropylene having a hydroxyl group grafted thereto. Such a hydroxyl group-containing propylene-based oligomer is produced by a known method (Japanese Patent Application Laid-Open No. 61-113675, Japanese Patent Application Laid-Open No. 50-1603).
94 and JP-A-56-88403). The hydroxyl group-containing propylene-based oligomer (C) used in the present invention has a number average molecular weight (M _N ) of 2000 to 2000.
0, preferably 2500 to 15000, and a hydroxyl value of 10 to 80, preferably 20 to 60. Examples of materials corresponding to this are Yumex (registered trademark) 1201H and Yumex (registered trademark) 1210 manufactured by Sanyo Kasei Co., Ltd.
And Umex® 1215.

The proportion of the hydroxyl group-containing propylene-based oligomer (C) in the polypropylene-based resin composition used in the present invention is 1 to 15% by weight, preferably 1 to 12% by weight. If the blending ratio is less than 1% by weight, the coating adhesion is lowered, and if it exceeds 15% by weight, the impact resistance at low temperature is lowered.

Examples of the inorganic filler (D) used in the present invention include talc, mica, wollastonite, calcium carbonate, barium sulfate, magnesium carbonate, clay, alumina, silica, calcium sulfate, carbon fiber, glass fiber, metal. Fibers, silica sand, quartzite, carbon black, titanium oxide, magnesium hydroxide, asbestos, zeolite, molybdenum, diatomaceous earth, sericite, shirasu, calcium hydroxide, calcium sulfite, sodium sulfate, bentonite, graphite and the like. .

The blending ratio of the inorganic filler (D) in the polypropylene resin composition used in the present invention is 2 to 30% by weight,
It is preferably 2 to 25% by weight. If it is less than 2% by weight, the rigidity and heat resistance are deteriorated, and if it exceeds 30% by weight, the impact strength and the appearance of the molded product are deteriorated.

The inorganic filler (D) has an average particle size of 3 μm from the viewpoint of improving rigidity, low temperature impact resistance and appearance of the molded product.
The following talc is preferred.

The resin composition used in the present invention can be produced by using a kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a hot roll. The temperature required for kneading is
It is usually 160 to 260 ° C., and the time is usually 1 to 20 minutes. Furthermore, the resin composition used in the present invention includes, in addition to these basic components, an antioxidant, an ultraviolet absorber, a lubricant, a pigment, an antistatic agent, a copper damage inhibitor, a flame retardant, a neutralizing agent, a foaming agent, a plasticizer. An additive such as a nucleating agent can be added within a range that does not impair the object of the present invention.

The kneaded resin composition is molded into a molded product by, for example, injection molding, extrusion molding or other various molding methods. As a polypropylene resin composition molded article,
Examples thereof include molded products of various shapes such as films, plates and fibers. For example, specific examples of injection-molded products include bumper parts such as bumpers, corner bumpers, spoilers, automobile exterior parts such as side moldings and mat guards,
Examples include automobile interior parts such as instrument panels, pillars, trims, and console boxes.

Next, the surface treatment method and the coating method will be described. In the present invention, the surface treatment of the polypropylene-based resin composition molded article is performed by irradiating the surface of the molded article with ultraviolet rays.

The ultraviolet rays with which the surface of the molded article is irradiated are ultraviolet rays having a wavelength of 300 nm or less, particularly 254 nm and 185 n.
It is an ultraviolet ray having a wavelength of m as a main working wavelength,
Higher strength is preferable. As an ultraviolet irradiation lamp,
It is preferably made of synthetic quartz.

In the present invention, it is not necessary to treat the surface of the polypropylene resin composition molded article with a solvent before irradiating it with ultraviolet rays, but degreasing which is well known in the art may be carried out. Examples of the solvent for degreasing the surface of the polypropylene resin composition molded article include aqueous solutions of alkalis, alcohols such as ethanol and isopropyl alcohol, and water. Examples of the method of bringing the solvent into contact with the surface of the polypropylene-based resin composition molded article include a coating or wiping method, a dipping method, and a spraying method. Also, a method of power washing an aqueous solution of acid or alkali can be used.

The ultraviolet irradiation time in the present invention is usually 2
It is 0 second to 10 minutes, preferably 30 seconds to 5 minutes.

Further, according to the present invention, after the surface of the molded product is irradiated with ultraviolet rays, it can be coated with a melamine-based, urethane-based, acrylic-based paint or the like. Preferred paints used in the present invention include melamine paints and urethane paints. The melamine-based paint is a melamine-curable paint, and includes, for example, a flexible type polyester melamine-based paint used for bumpers and the like. Examples of urethane-based paints include paints having a urethane structure such as acrylic urethane, polyester urethane, and one-component urethane paints.

[0037]

As described in detail above, according to the present invention,
It is possible to provide a surface treatment method for a polypropylene-based resin composition molded article which is extremely excellent in paintability, adhesiveness, printability, etc., a coating method for the molded article, and the resin-coated molded article.

[0038]

EXAMPLES The present invention will be specifically described with reference to Examples.
The present invention is not limited to these examples. [Paintability (Initial Adhesion) Evaluation Method] The surface treatment effect of the molded product was evaluated by applying a razor blade to the coating film of the painted molded product obtained in Examples and Comparative Examples, and using a razor blade 100
The remaining Goban when the car (10 length x 10 width) is carved and a 24 mm wide cellophane tape (trade name, manufactured by Nichiban Co., Ltd.) is crimped on it with a finger and then the end face is grasped and peeled off at once. It carried out by the number of eyes (residual rate (%)).

Example 1 An ethylene-propylene random copolymer having an ethylene / propylene ratio of 28/72 (weight ratio) was included, and the intrinsic viscosity [η] p of the crystalline polypropylene part was 1.02 d.
l / g, the ratio Q value of molecular weight measured by GPC (weight average molecular weight M _W / number-average molecular weight M _N) is the 3.4,20 ° C. xylene-soluble portion 0.9 wt%, and an ethylene - propylene random 57 parts by weight of a crystalline ethylene-propylene block copolymer having a copolymer portion of 12% by weight of the crystalline ethylene-propylene block copolymer, and having a Mooney viscosity (ML _{1 + 4} ) of 52 measured at 100 ° C., 25 parts by weight of an ethylene-propylene copolymer rubber having a propylene content of 27% by weight, a hydroxyl group-containing propylene oligomer having a number average molecular weight of 4000 and a hydroxyl value of 50 (Sanyo Kasei Co., Ltd.)
10 parts by weight of Umex (registered trademark) 1210) and 8 parts by weight of talc having an average particle diameter of 2.2 μ were uniformly premixed with a Henschel mixer, and then a continuous twin-screw kneader (Japan Steel Works) Made TEX44SS 30BW-2
(V type) was melt-kneaded at 220 ° C. to obtain pellets. Using these pellets, injection molding machine Neomat 515/150 manufactured by Sumitomo Heavy Industries, Ltd., 100 × 40 at 220 ° C.
A 0 × 3 mmt coating test flat plate was prepared. The obtained flat plate was placed in front of an ultraviolet irradiation device equipped with a low-pressure mercury lamp (200 W made of synthetic quartz), the distance between the light source and the surface of the molded product was kept at 15 cm, and 254 nm and 1 were set in an air atmosphere.
Ultraviolet rays with a wavelength of 85 nm as the main working wavelength (U
V) was irradiated for 60 seconds to perform surface treatment. Next, on the surface, acrylic urethane paint R2 manufactured by Nippon Bee Chemical Co., Ltd.
No. 71 was used for spray coating, baking was performed at 90 ° C. for 30 minutes and drying, and the initial adhesion of the coated molded article was measured. Table 1 shows the results.

Comparative Example 1 The initial adhesion of the coated molded article was measured in the same manner as in Example 1 except that the ultraviolet irradiation was not performed. Table 1 shows the results.

Comparative Example 2 The initial adhesion of the coated molded article was measured in the same manner as in Example 1 except that the amount of the crystalline ethylene-propylene block copolymer was 67 parts by weight and the hydroxyl group-containing propylene oligomer was not added. Table 1 shows the results.

Example 2 40 parts by weight of the crystalline ethylene-propylene block copolymer used in Example 1, 25 parts by weight of ethylene-propylene copolymer rubber, 10 parts by weight of hydroxyl group-containing propylene oligomer and 25 parts of talc. The initial adhesion of the coated molded article was measured in the same manner as in Example 1 except that the parts by weight were compounded. Table 1 shows the results.

Comparative Example 3 The initial adhesion of the coated molded article was measured in the same manner as in Example 2 except that the ultraviolet irradiation was not performed. Table 1 shows the results.

Comparative Example 4 The initial adhesion of a coated molded article was measured in the same manner as in Example 2 except that the crystalline ethylene-propylene block copolymer was 50 parts by weight and no hydroxyl group-containing propylene oligomer was added. Table 1 shows the results.

[0045]

[Table 1]

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Claims (17)

[Claims] 1. Crystalline ethylene-propylene block copolymer (A) 15 to 92% by weight, ethylene-propylene copolymer rubber (B) 5 to 40% by weight, hydroxyl group-containing propylene-based oligomer (C) 1 to 15 A surface treatment method for a polypropylene-based resin composition molded article, which comprises irradiating a molded article of a polypropylene-based resin composition composed of 1% by weight and 2 to 30% by weight of an inorganic filler (D) with ultraviolet rays of 300 nm or less. 2. A crystalline ethylene-propylene block copolymer (A) is an ethylene-propylene random copolymer part in which the crystalline polypropylene part and ethylene / propylene = 20/80 to 60/40 (weight ratio). And the intrinsic viscosity [η] p of the crystalline polypropylene part is 0.8 to 2.0 dl / g, and the ratio Q of the molecular weight measured by GPC.
Value (weight average molecular weight M _W / number average molecular weight M _N ) is 3.0
˜5.0, 20 ° C. Xylene solubles is 1.5 wt% or less, and the ethylene-propylene random copolymer part is 5 to 20 wt% of the crystalline ethylene-propylene block copolymer (A). A surface treatment method for a polypropylene-based resin composition molded article according to claim 1. 3. An ethylene-propylene copolymer rubber (B)
, Mooney viscosity (ML _{1 + 4} 100 ° C) 10-100,
The surface treatment method for a polypropylene-based resin composition molded article according to claim 1, which has a propylene content of 20 to 75% by weight. 4. A hydroxyl group-containing propylene-based oligomer (C)
Is a number average molecular weight (M _N ) of 2000 to 20000 and a hydroxyl value of 10 to 80. The surface treatment method for a polypropylene-based resin composition molded article according to claim 1. 5. The surface treatment method for a polypropylene-based resin composition molded article according to claim 1, wherein the inorganic filler (D) is talc having an average particle size of 3 μm or less. 6. A crystalline ethylene-propylene block copolymer (A) 15-92% by weight, an ethylene-propylene copolymer rubber (B) 5-40% by weight, a hydroxyl group-containing propylene-based oligomer (C) 1-15. After irradiating an ultraviolet ray of 300 nm or less to a molded product of a polypropylene-based resin composition composed of 1% by weight and an inorganic filler (D) of 2 to 30% by weight,
A method for coating a polypropylene-based resin composition molded article, which comprises coating with a paint. 7. A crystalline ethylene-propylene block copolymer (A) is an ethylene-propylene random copolymer part in which the crystalline polypropylene part and ethylene / propylene = 20/80 to 60/40 (weight ratio). And the intrinsic viscosity [η] p of the crystalline polypropylene part is 0.8 to 2.0 dl / g, and the ratio Q of the molecular weight measured by GPC.
Value (weight average molecular weight M _W / number average molecular weight M _N ) is 3.0
˜5.0, 20 ° C. Xylene solubles is 1.5 wt% or less, and the ethylene-propylene random copolymer part is 5 to 20 wt% of the crystalline ethylene-propylene block copolymer (A). A method for coating a polypropylene-based resin composition molded article according to claim 6. 8. An ethylene-propylene copolymer rubber (B)
, Mooney viscosity (ML _{1 + 4} 100 ° C) 10-100,
The method for coating a polypropylene-based resin composition molded article according to claim 6, which has a propylene content of 20 to 75% by weight. 9. A hydroxyl group-containing propylene-based oligomer (C)
Is a number average molecular weight (M _N ) of 2000 to 20000 and a hydroxyl value of 10 to 80, and the method for coating a polypropylene resin composition molded article according to claim 6. 10. The method for coating a polypropylene-based resin composition molded article according to claim 6, wherein the inorganic filler (D) is talc having an average particle diameter of 3 μm or less. 11. The method for coating a polypropylene resin composition molded article according to claim 6, wherein the coating material is a urethane coating material or a melamine coating material. 12. A crystalline ethylene-propylene block copolymer (A) 15-92% by weight, an ethylene-propylene copolymer rubber (B) 5-40% by weight, a hydroxyl group-containing propylene-based oligomer (C) 1-15. A polypropylene-based resin composition comprising 1% by weight and 2 to 30% by weight of an inorganic filler (D), which is obtained by irradiating the molded article with ultraviolet rays having a wavelength of 300 nm or less, and then coating it with a paint. Resin coated molded product. 13. A crystalline ethylene-propylene block copolymer (A), and a crystalline polypropylene portion, ethylene / propylene = 20/80 to 60/40 (weight ratio), an ethylene-propylene random copolymer portion. And the intrinsic viscosity [η] p of the crystalline polypropylene part is 0.8 to 2.0 dl / g, and the ratio Q of the molecular weight measured by GPC.
Value (weight average molecular weight M _W / number average molecular weight M _N ) is 3.0
˜5.0, 20 ° C. Xylene solubles is 1.5 wt% or less, and the ethylene-propylene random copolymer part is 5 to 20 wt% of the crystalline ethylene-propylene block copolymer (A). The polypropylene-based resin coated molded product according to claim 12. 14. The ethylene-propylene copolymer rubber (B) has a Mooney viscosity (ML _{1 + 4} 100 ° C.) of 10-1.
The polypropylene resin-coated molded product according to claim 12, having a propylene content of 00 and a propylene content of 20 to 75% by weight. 15. The hydroxyl group-containing propylene-based oligomer (C) has a number average molecular weight (M _N ) of 2000 to 2000.
The polypropylene-based resin coated molded article according to claim 12, having a hydroxyl value of 0 and a hydroxyl value of 10 to 80. 16. The polypropylene resin-coated molded article according to claim 12, wherein the inorganic filler (D) is talc having an average particle size of 3 μm or less. 17. The polypropylene resin-coated molded product according to claim 12, wherein the paint is a urethane paint or a melamine paint.