JPH0762173A - Olefin polymer composition and coated molding produced therefrom - Google Patents

Abstract

PURPOSE:To produce an olefin polymer compsn. which exhibits practically sufficient coatability and adhesion to a coating film when coated with an amino- resin-based coating material without detriment to the mechanical characteristics inherent in an olefin polymer and to provide an article coated with an amino- resin-based coating material without any pretreatment such as primer coating. CONSTITUTION:The title compsn. comprises a hydroxylated olefin polymer and an org. or inorg. acid. A molding of the compsn. can directly be coated with an amino-resin-based coating material without any pretreatment such as primer coating, giving a coated article excellent in adhesion to the coating film. Excellent in mechanical characteristics such as elastic modulus and impact resistance, the molding can widely be used, e.g. for an automotive bumper.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an olefin polymer composition and a coated body of the composition-formed body. More specifically, the present invention relates to an olefin polymer composition having excellent mechanical properties and excellent paintability and adhesiveness of an amino resin paint, and a coated body of a molded product of the composition.

[0002]

2. Description of the Related Art Conventionally, olefin resins have been widely used industrially because of their excellent mechanical properties and moldability. On the other hand, olefin resins generally have poor coatability and adhesiveness, and therefore usually require pretreatment. For example, in coating, a process of applying a 1,1,1-trichloroethane vapor treatment and then applying a specific primer is generally used (Painting Engineering Vol. 19, No. 4, 1984). On the other hand, many attempts have been made to improve the paintability and adhesiveness of olefin-based resins to enable direct coating. For example, the most commonly used method is to modify an olefin resin with an unsaturated carboxylic acid such as maleic anhydride or an anhydride thereof (JP-A-59-159).
844, etc.). However, with such a method, sufficient adhesion could not be obtained.

Further, many attempts have been made to modify with an unsaturated hydroxy compound instead of the unsaturated carboxylic acid or its anhydride (JP-A-60-55012, etc.). Among these, those which can obtain sufficient adhesion to an amino resin-based coating even if sufficient adhesion is obtained when a urethane coating is used (Japanese Patent Application No. 5-56080) There wasn't. The amino resin-based paint has a merit that it is easier to handle than the two-liquid type urethane paint because it is a one-pack type, but has a drawback that the adhesion with the olefin-based resin is insufficient.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is sufficiently practical for amino resin-based paints without impairing the mechanical properties originally possessed by olefin-based resins. An object of the present invention is to provide an olefin polymer composition having paintability and adhesiveness, and to provide a coated article coated with an amino resin-based coating without performing pretreatment such as primer coating.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in order to achieve the above-mentioned object, a hydroxy-modified olefin polymer and an olefin polymer composition containing an acid component were obtained. The inventors have found that they meet the above-mentioned objects and completed the present invention. That is, the above-mentioned problems are (A) a hydroxy-modified olefin polymer, and (B) an olefin polymer composition containing an organic acid or an inorganic acid, and a coating in which an amino resin-based coating material is applied to a molded body of the composition. Solved by the body.

The present invention will be described in detail below. Examples of the olefin polymer that can be used in the present invention include low density polyethylene, medium density polyethylene, high density polyethylene, linear low density polyethylene, polypropylene, ethylene-propylene block copolymer, ethylene-propylene random copolymer, polybutene. Etc., or a mixture thereof. Of these, crystalline polypropylene-based resins such as propylene homopolymer, ethylene-propylene block copolymer, ethylene-propylene random copolymer and the like, or a mixture thereof are preferable.

The hydroxy-modified olefin polymer according to the present invention can be obtained by various methods. For example, (1) a method of modifying an olefin polymer with an unsaturated hydroxy compound, (2) modifying an olefin polymer with an unsaturated compound having no hydroxy group, and then using the modified product and a compound having a hydroxy group. A method of introducing a hydroxy group by reacting

In the method (1), the hydroxy-modified olefin polymer can be obtained by heat-treating the olefin polymer with an unsaturated hydroxy compound in the presence of an organic peroxide. Specifically, for example, an olefin polymer, an organic peroxide and an unsaturated hydroxy compound are premixed with a Henschel mixer or the like, and then heated with a kneading machine such as a normal twin-screw extruder, a single-screw extruder or a Banbury mixer. It can be prepared by kneading. The temperature at the time of kneading varies depending on the kinds of the olefin polymer and the organic peroxide used, but is usually between 100 and 300 ° C.

As the organic peroxide used in the modification of the olefin polymer, dibenzoyl peroxide,
p-chlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, 1,3-bis (t-butylperoxy) isopropylbenzene, 2,5-bis (t- Butylperoxy) -2,5-dimethylhexane, 2,5
-Bis (t-butylperoxy) -2,5-dimethyl-
3-hexyne, 1,1-bis (t-butylperoxy)
-3,3,5-Trimethylcyclohexane, t-butylperoxybenzoate and the like can be used, and these may be diluted with an inert substance such as a plasticizer, calcium carbonate and white carbon. The amount of the organic peroxide compounded during the modification is 0.01 to 3 parts by weight with respect to 100 parts by weight of the olefin-based polymer, and is 0.1% by weight in order to increase the modification amount of the unsaturated hydroxy compound which is the modifier. It is preferably 2 parts by weight or more and 2 parts by weight or less in order to prevent significant crosslinking of the olefin-based polymer and reduction in molecular weight.

In the present invention, the unsaturated hydroxy compound used for modifying the olefin polymer is a compound having at least one unsaturated bond in the molecule and having a hydroxyl group, for example, hydroxyethyl acrylate. , Hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, polyethylene glycol monoacrylate, polyethylene glycol monomethacrylate, polypropylene glycol monoacrylate, polypropylene glycol monomethacrylate, glycerol mono or diacrylate, glycerol mono Or dimethacrylate, trimethylolpropane mono or diacrylate, trimethylol Propane mono- or dimethacrylate, ethylene glycol monoallyl ether, propylene glycol monoallyl ether, polyethylene glycol monoallyl ether, polypropylene glycol monoallyl ether, ortho, meta, or para-hydroxymethylstyrene, 3-hydroxy-1-propene, or the like. A mixture of Of these,
Hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, polyethylene glycol monoacrylate with oxyethylene chain polymerization degree of 10 or less,
Polyethylene glycol monomethacrylate with oxyethylene chain polymerization degree of 10 or less, oxypropylene chain polymerization degree of 1
Polypropylene glycol monoacrylate of 0 or less,
Oxypropylene chain Polypropylene glycol monomethacrylate having a degree of polymerization of 10 or less is preferable because it is easy to modify and the coatability is particularly good.

The amount of the unsaturated hydroxy compound used to obtain the hydroxy-modified olefin polymer is 0.1 to 15 parts by weight, preferably 1 to 6 parts by weight, based on 100 parts by weight of the olefin polymer. If it is less than 0.1 part by weight, the coating property is insufficient, and if it exceeds 15 parts by weight, the amount of the unsaturated hydroxy compound that is not grafted increases, which adversely affects the physical properties and appearance of the molded article.

As a specific example of the method (2) for obtaining the hydroxy-modified olefin polymer, for example, an olefin polymer can be obtained by using maleic anhydride, maleimidic anhydride, itaconic anhydride, citraconic anhydride, or tetrahydrophthalic anhydride. Examples include a method of modifying with an unsaturated dicarboxylic acid anhydride such as an anhydride, and then reacting the modified product with ethanolamine or the like to obtain a hydroxy-modified olefin polymer.

The amount of the hydroxy-modified olefin polymer contained in the olefin polymer composition of the present invention is 5.0 to 99.95% by weight, preferably 10.0 to 50. It is 0% by weight. 5.0% by weight
If it is less than 99% by weight, sufficient paintability cannot be obtained.
If it exceeds the above range, the amount of the acid component used is limited, so that sufficient paintability cannot be obtained.

In the present invention, the organic acid means an organic compound having an acidity, and examples thereof include carboxylic acid, sulfonic acid, sulfinic acid, phenols, and the like. For example, acetic acid, oxalic acid, tartaric acid, benzoic acid, picric acid, salicylic acid, Methyl sulfonic acid, paratoluene sulfonic acid, dodecylbenzene sulfonic acid and the like can be mentioned.

In the present invention, the inorganic acid means a compound in which an acid group and hydrogen are bonded, and examples thereof include phosphoric acid, polyphosphoric acid, phosphorous acid, hypophosphorous acid and the like.

The organic acid or the inorganic acid contained in the olefin polymer composition of the present invention may be used alone or in combination of two or more kinds, and the amount of the organic acid or inorganic acid to be used is from 0.05 to relative to the composition. 5.0% by weight, preferably 0.05-2.0
% By weight. If it is less than 0.05% by weight, sufficient coatability cannot be obtained, and if it exceeds 5.0% by weight, bleeding to the surface of the molded article becomes severe and it is not preferable in terms of physical properties.

In the present invention, in addition to (A) the hydroxy-modified olefin polymer and (B) the organic acid or the inorganic acid in the olefin polymer composition, in order to improve mechanical properties such as elastic modulus and impact resistance. (C) an olefin polymer,
(D) Elastomer, (E) Inorganic filler, etc. can be contained.

Examples of the olefin polymer (C) include those mentioned above. Examples of the (D) elastomer include polybutadiene, polyisoprene, isobutylene-isoprene copolymer, butadiene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, polychloroprene rubber, and complete or Partially hydrogenated products, ethylene-propylene copolymer rubber, ethylene-butene copolymer rubber, ethylene-propylene-diene copolymer rubber and the like can be mentioned. These are 1
Although it can be used in various types, it is also possible to use a mixture of two or more types.

The amount of the (C) olefin polymer and / or (D) elastomer contained in the olefin polymer composition of the present invention is 94.95% by weight or less, preferably 8%.
The content is 9.95% by weight or less, and if it exceeds 94.95% by weight, sufficient coatability cannot be obtained. Among these, it is most preferable to use (C) and (D) together, and the weight ratio of (C) olefin polymer / (D) elastomer is 0.01 to 1
00, more preferably 0.1 to 20 is suitable. If it deviates from this range, the balance of mechanical properties will be lost.

In the present invention, the inorganic filler (E) may be added to the olefin polymer composition for the purpose of improving the elastic modulus. Examples of the inorganic filler include talc, wollastonite, silica, mica, calcium carbonate, potassium titanate, glass fiber, alumina, aluminum hydroxide or a mixture thereof. The amount of the inorganic filler (E) that can be contained in the composition can be mixed in the composition in a range not exceeding 35% by weight, preferably not exceeding 25% by weight. When it exceeds 35% by weight, the moldability of the composition is deteriorated and the impact resistance is significantly lowered.

To the olefin polymer composition of the present invention, various additives such as an antioxidant, an ultraviolet absorber, a stabilizer, a colorant, a release agent, a filler and a reinforcing material may be added depending on the purpose. You can also

In the present invention, (A) a hydroxy-modified olefin polymer and (B) an organic acid or an inorganic acid, if necessary, (C) an olefin polymer, (D) an elastomer, or (E) an inorganic filler. Can be mixed in suitable proportions. The mixing can be performed by a method of melt-kneading using, for example, a single-screw extruder, a multi-screw extruder, a Banbury mixer, a mixing roll, a kneader and the like. The olefin polymer composition thus obtained can be formed into a molded product by a molding method such as injection molding, extrusion molding, or press molding. The molded body thus obtained can be used as it is or simply by washing the surface of the molded body with a neutral detergent or the like.
The amino resin-based paint can be applied without applying a primer or the like. Further, it is of course possible to coat the molded article by subjecting it to usual trichloroethane treatment, primer treatment and the like.

The amino resin-based paint referred to in the present invention contains an amino resin as a cross-linking agent and a resin used in combination with the amino resin (hereinafter, abbreviated as combined resin).
Representative amino resins include melamine resins, benzoguanamine resins, urea resins and the like. Alkyd resin, polyester resin, acrylic resin, epoxy resin and the like are usually used as the combined resin. Examples of amino resin-based paints include melamine alkyd resin paints, melamine acrylic resin paints, melamine epoxy resin paints,
Examples thereof include melamine epoxy acrylic resin paint and melamine epoxy alkyd resin paint. The method for applying the amino resin-based paint is not particularly limited, and a commonly used method can be applied. For example, hand spraying, auto spraying, electrostatic coating and the like can be used.

[0024]

The organic acid or inorganic acid used in the present invention has a function of promoting the reaction in the crosslinking reaction of the amino resin type coating material. In the present invention, since the organic acid or the inorganic acid is present in the olefin polymer composition molded article, the reaction between the hydroxyl group of the hydroxy-modified olefin polymer and the functional group in the amino resin-based coating is promoted, It is presumed that the affinity between the molded product and the amino resin-based paint is increased, and the adhesion of the coating film is significantly improved.

When the olefin polymer and / or elastomer is used in the present invention, the balance of mechanical properties is maintained. On the other hand, the use of the inorganic filler increases the elastic modulus of the molded article of the composition and improves the mechanical properties.

[0026]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

The adhesion of the coated body was evaluated by the following method. The injection-molded flat plate of the olefin polymer resin composition was washed with a household neutral detergent, washed with water, dried, and then coated with an amino resin-based coating (Kansai Paint Co., Ltd., Soflex # 1211, one-pack type). A notch having a width of 1 cm was cut on the coated flat plate, and a peeling strength of 180 ° was measured at a pulling speed of 50 mm / min.

The flexural modulus and Izod impact value were measured as the mechanical properties of the molded product. The test piece was made by injection molding, and the flexural modulus was ASTM D79.
0, Izod impact value was measured according to ASTM D256 (notched, 23 ° C).

The components of the compositions used in the examples and comparative examples are as follows. (Hydroxy-modified olefin polymer A) 1. 2-hydroxyethyl methacrylate was added to a propylene homopolymer.
Melt flow rate (hereinafter referred to as MF
R) Modified product A having 90 g / 10 min.

(Hydroxy-modified olefin polymer B)
1.1% by weight of ethylene glycol monoallyl ether was added to propylene homopolymer, and MFR 150 g / 10
This is the modified product B.

(Polypropylene) A propylene homopolymer having an MFR of 70 g / 10 minutes.

(Ethylene-propylene rubber) An ethylene-propylene rubber having an ethylene content of 41% by weight and an MFR of 1.1 g / 10 minutes.

(Talc) Average particle size 2 μm.

Melt kneading was carried out at the composition ratios shown in Tables 1 and 2. The olefin polymer composition obtained by kneading was applied to the coated body by the above-mentioned method, and then evaluated. The evaluation results are shown in Tables 1 and 2.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

As described above, the molded product of the olefin polymer composition of the present invention can be directly coated with the amino resin-based paint without pretreatment such as primer coating. Has excellent coating adhesion. Further, the molded body is excellent in mechanical properties such as elastic modulus and impact resistance and is well balanced.

The composition and coated body of the present invention can be used in various fields, and typical applications include exterior parts such as automobile bumpers and bumper corners, and interior parts such as instrument panels and door liners. Is mentioned. When painting automobile bumpers, etc.
Direct overcoating is possible without the need for a vapor treatment step of 1,1-trichloroethane and a primer application step.

Claims (2)

[Claims] 1. An olefin polymer composition containing (A) a hydroxy-modified olefin polymer and (B) an organic acid or an inorganic acid. 2. A coated body obtained by applying the amino resin-based paint to the molded body of the composition according to claim 1.