JPH093270A - Thermoplastic resin composition and its molded product - Google Patents

Abstract

PURPOSE: To obtain the subject composition containing a mixture of a polypropylene-based polymer and a specific ethylene-ethyl acrylate copolymer in a specific ratio, maintaining mechanical properties, etc., excellent in coating properties, especially close adhesion and recoating properties, and suitable to a bumper of an automobile, etc. CONSTITUTION: This thermoplastic resin composition consists of (A) 80-99.5wt.% polypropylene based polymer, (B) an ethylene ethyl acrylate (M1 ) copolymer containing 5-35wt.% M1 and having >=100g/10min melt index value (MI) and (C) an ethylene-M1 copolymer containing 5-35wt.% M1 and having <=40g/10min MI, and the ratio of the total amount of the component B and C is set as 0.5-20wt.% and also the ratio of the component C to the component B is set as 1-99wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition excellent in impact resistance and paintability and a molded product thereof. In particular, the present invention relates to a thermoplastic resin composition having excellent adhesion and recoatability to a primerless paint and a molded product thereof.

[0002]

2. Description of the Related Art Polypropylene polymers have mechanical properties,
It has excellent properties such as moldability and chemical resistance.
Although it is inexpensive, it has problems in impact resistance and paintability. Therefore, a thermoplastic elastomer is added to a polypropylene polymer for the purpose of improving impact resistance and paintability when used for automobile bumpers (Japanese Patent Laid-Open No. 63-3 / 1988).
No. 9951, JP-A-63-122752, etc.), a vinyl polymer is blended with a polypropylene polymer. Examples of the latter include, for example, blending a polystyrene-modified propylene-based copolymer produced by a specific method with a propylene-based polymer (JP-A-58-58).
No. 93730), a method of blending a propylene-based polymer with a multi-phase structure graft copolymer comprising an olefin-based copolymer and a vinyl-based copolymer (JP-A-2-1730).
No. 49) is disclosed.

[0003]

In any of these methods, if the surface is not washed, the adhesion with the primer will be extremely reduced. Therefore, before painting 1,
Clean the surface of the molded product with a halogen-containing organic solvent such as 1,1-trichloroethane or trichloroethylene,
After that, there was a problem that primer coating and top coating had to be performed. In addition, there is a problem that the adhesion to the primerless paint cannot be obtained at all.

The present invention has been made to solve the above-mentioned problems, and has impact resistance and coating properties while maintaining the characteristics of polypropylene polymer such as mechanical properties, moldability and chemical resistance. To provide a thermoplastic resin composition having improved properties and a molded article thereof. In particular, it is to provide a thermoplastic resin composition having good adhesion and recoatability to a primerless paint and a molded article thereof.

[0005]

In order to solve the above problems, in the first invention, a polypropylene polymer (1) is used.
Is 80-99.5% by weight, and ethyl acrylate is 5-3.
5 wt% content and melt index value of 100
The ethylene-ethyl acrylate copolymer (2) which is g / 10 min or more (measured under a load of 2.16 kg at 190 ° C .: all melt index values are the same under the same measurement conditions) and ethyl acrylate in an amount of 5 to 35 Wt% content,
And an ethylene-ethyl acrylate copolymer (3) having a melt index value of 40 g / 10 min or less, the ethylene-ethyl acrylate copolymer (2) and the ethylene-ethyl acrylate copolymer (3) Is 0.5 to 20% by weight, and the ratio of ethylene-ethyl acrylate copolymer (3) to ethylene-ethyl acrylate copolymer (2) is 1 to 99% by weight. The gist is a resin composition.

A second aspect of the invention has as its gist a thermoplastic resin composition containing the thermoplastic resin composition according to the first aspect, and further containing a thermoplastic elastomer.

The third invention has as its gist a thermoplastic resin in which an inorganic filler is further dispersed in the thermoplastic resin described in the first invention or the second invention.

The fourth invention has as its gist a resin molded product obtained by molding the thermoplastic resin described in the first invention to the third invention into a predetermined shape. Next, each constituent element of the present invention will be described.

The polypropylene-based polymer (1) used in the present invention is a crystalline polypropylene, and is a propylene homopolymer and other α-containing propylene.
It means a copolymer with an olefin. In these homopolymers or copolymers, it is desirable to contain 75% by weight or more of propylene.

Specifically, isotactic polypropylene, crystalline propylene-ethylene random copolymer,
Typical examples include a crystalline propylene-ethylene block copolymer and a crystalline propylene-butene-1 random copolymer. These propylene-based polymers may be mixed and used.

The ethylene-ethyl acrylate copolymer (2) has an ethyl acrylate content of 5 to 35% by weight and a melt index of 100 g / 10 min or more. More preferably, the ethyl acrylate content is 10 to 30% by weight, and the melt index value is 150 g / 10 min or more. When the content of ethyl acrylate is less than 5% by weight, the swelling property with respect to a usual coating solvent is lowered, so that the adhesion of the coating is lowered. When the content of ethyl acrylate is more than 35% by weight, the solvent resistance to a usual coating solvent is lowered too much, so that the recoating performance (the lifting of the coating film may occur during overcoating) tends to be insufficient. If the melt index is less than 100 g / 10 min, the orientation to the surface during molding becomes low, and good coatability cannot be obtained.

The ethylene-ethyl acrylate copolymer (3) has an ethyl acrylate content of 5 to 35% by weight and a melt index value of 40 g / 10 min or less. More preferably, the content of ethyl acrylate is 10 to 30% by weight and the value of melt index is 30 g / 10 min or less.

The ethylene-ethyl acrylate copolymer (3) cannot provide good adhesion and the like when added alone, but when used in combination with the ethylene-ethyl acrylate copolymer (2), good adhesion is obtained. Solvent resistance and recoatability can be imparted without impairing adhesion.

The addition amount of each ethylene-ethyl acrylate copolymer in the system is 0.5 to 5 in terms of the total of the ethylene-ethyl acrylate copolymer (2) and the ethylene-ethyl acrylate copolymer (3). It is 20% by weight. More preferably, it is 1 to 10% by weight. If the addition amount is less than 0.5% by weight, no effect is exhibited and good adhesion cannot be obtained. On the other hand, if the amount added exceeds 20% by weight, the solvent resistance of the thermoplastic resin composition tends to deteriorate, and the recoatability tends to be insufficient.

The ratio of the ethylene-ethyl acrylate copolymer (3) to the ethylene-ethyl acrylate copolymer (2) is 1 to 99% by weight. If the amount is less than 1% by weight, the recoat performance, especially the tilt recoat performance tends to be insufficient. If it exceeds 99% by weight, the adhesion tends to be insufficient. Preferably, the ratio of the ethylene-ethyl acrylate copolymer (3) to the ethylene-ethyl acrylate copolymer (2) is 10 to 90% by weight. More preferably, it is 20 to 85% by weight. Most preferably, it is 30 to 80% by weight. In addition, the ethylene-ethyl acrylate copolymer (2) and the ethylene-ethyl acrylate copolymer (3) are 1 type or 2 types, respectively.
A mixture of more than one species can be used.

The thermoplastic elastomer used in the second invention is specifically a polybutadiene, a styrene-diene copolymer, an acrylonitrile-butadiene copolymer, a diene rubber such as polyisoprene, or a styrene-butadiene block copolymer. , Hydrogenated styrene-butadiene block copolymer, ethylene-propylene elastomer, ethylene-propylene-diene elastomer, ethylene-based ionomer resin, hydrogenated styrene-isoprene block copolymer and the like. These thermoplastic elastomers can be used alone or in combination of two or more.

Among these thermoplastic elastomers, ethylene-propylene elastomer and ethylene-propylene-diene elastomer are preferable from the viewpoints of impact resistance, gasoline resistance and surface appearance of molded articles. More preferably,
The Mooney viscosity (ML _{1 + 4} , 100 ° C.) is 5 to 150.

From the viewpoint of mechanical properties and heat resistance, the amount of the thermoplastic elastomer added is 1 to 200 parts by weight, more preferably 1 to 100 parts by weight, and particularly preferably 1 to 100 parts by weight, based on 100 parts by weight of the polypropylene polymer (1). Preferably 1 to 50
Parts by weight. If it is less than 1 part by weight, the elasticity of the resin composition tends to be small, and if it exceeds 200 parts by weight, the heat resistance tends to be lowered.

The inorganic filler used in the present invention is
Powder and granular fillers such as calcium sulfate, calcium silicate, clay, diatomaceous earth, talc, alumina, silica sand, glass powder, iron oxide, metal powder, graphite, silicon carbide, silicon nitride, silica, boron nitride, aluminum nitride and carbon black, Mica, glass plate, sericite, pyrofight,
Metal foil such as aluminum flakes, flat or scale-like filler such as graphite, shirasu balloon, metal balloon, glass balloon, hollow filler such as pumice, glass fiber, carbon fiber, graphite fiber, whiskers, metal fiber, silicone Examples include carbide fibers, mineral fibers such as asbestos and wstonite, and the like.

Of these, calcium carbonate, barium sulfate and talc are preferable from the viewpoint of mechanical properties. Further, talc is most preferable in terms of mechanical properties, surface appearance of the molded product, and heat resistance. The shape may be powdery, flat, scale-like, needle-like, spherical, hollow or fibrous. Talc may be generally commercially available, but particularly preferred is one having an average particle size of 1 to 4 μm. These inorganic fillers can be used alone or in combination of two or more.

The surface of the inorganic filler is stearic acid, oleic acid, in order to have an affinity with the thermoplastic resin.
It is preferable to carry out the surface treatment using palmitic acid or a metal salt thereof, paraffin wax, polyethylene wax or a modified product thereof, organic silane, organic borane, organic titanate and the like. The inorganic filler may be added in an amount of 200 parts by weight or less based on 100 parts by weight of the total amount of the thermoplastic resin. This blend amount is 2
If it exceeds 100 parts by weight, the impact strength of the molded article will be reduced, which is not preferable.

In the present invention, within the scope of the present invention, inorganic flame retardants such as magnesium hydroxide and aluminum hydroxide, organic flame retardants such as halogen type and phosphorus type, metal powders, antioxidants, and ultraviolet rays. Additives such as an inhibitor, a lubricant, a dispersant, a coupling agent, a foaming agent, a cross-linking agent, a colorant, and carbon black may be added.
The thermoplastic resin composition of the present invention has a temperature of 150 to 350 ° C.
It is manufactured by melting and mixing in. If the temperature is lower than 150 ° C., the melting is incomplete, the melt viscosity is high, the mixing becomes insufficient, and phase separation or layered peeling appears in the molded product, which is not preferable. On the other hand, when the temperature exceeds 350 ° C., the resin to be mixed is decomposed, which is not preferable.

As a method of melting and mixing, Banbury
It can be carried out by a commonly used kneading machine such as a mixer, a pressure kneader, a kneading extruder, a twin-screw extruder or a roll.

The thermoplastic resin composition of the present invention is molded into a predetermined shape by a method such as injection molding or extrusion molding.

Since the thermoplastic resin composition of the present invention is excellent in mechanical properties, molding processability, impact resistance, adhesiveness and paintability, it can be used in various applications. For example, it can be used for bumpers, moldings, mudguards, other electric products, construction members, etc. as automobile parts. Among them, it is particularly suitable for use as an automobile bumper.

[0026]

EXAMPLES The present invention will be more specifically described below with reference to Examples and Comparative Examples. In these examples,% represents% by weight unless otherwise specified. The measurement and evaluation items in each example were performed according to the following methods. (1) Izod impact test (abbreviated as Izod in the table):
JIS K 7110 (size of test piece: 13 mm x 6
5mm × 6mm, with notch, unit is [kg ・ cm / c
m ² ]) (2) Weighted deflection temperature test (abbreviated as weighted deflection in the table):
JIS K 7207 (Size of test piece: 13 mm x 1
30 mm × 6 mm, measurement is performed at 18.6 kg / cm ² ) (3) Coating film adhesion test (abbreviated as coating film adhesion in the table): Test piece (size: 45 mm × 90 mm × 4 mm) with primerless paint ("Primac No. 201" (paint made by NOF Corporation)) and then baked (80 ° C, 40 ° C)
Minutes). After that, 11 vertical and horizontal cuts at 1 mm intervals were inserted by a knife until the test piece was reached, and 100 squares each having a side length of 1 mm were formed in a grid pattern.
A cellophane adhesive tape (manufactured by Nichiban Co., Ltd.) was attached to the grid, and when it was instantly peeled off, it was represented by the number of squares remaining without peeling. (4) Recoatability test (abbreviated as recoatability in the table): The same primerless paint was applied to the entire surface of a test piece prepared in the same manner as the coating film adhesion test piece, and left at room temperature to change the coating film surface. Were observed and classified as follows. ⊚: No abnormality in the coating film ○: Swelling of the coating film Δ: Partial peeling of the coating film: Peeling of the entire coating film (5) Tilt recoatability test (abbreviated as tilt recoatability in the table): Primerless paint on the test piece ( "Primac N
o. 201 "(Nippon Oil & Fats Co., Ltd. paint) with a gradient in the film thickness (80 ° C, 40 minutes baking), then the same primerless paint is overlaid and left at room temperature to leave the coating film surface. Was observed and classified as follows. ○: No abnormality in the coating film △: Partially swelling of the coating film ×: Partial peeling of the coating film (6) Appearance: Simulated bumper (460 mm length × 120 mm width ×
Height 56mm, bumper-back has 4 ribs, thickness 3
mm) was molded and the appearance (presence or absence of flow mark) was examined. The abbreviations in the table are as follows. EEA: ethylene-ethyl acrylate copolymer, A
To H differ in acrylic acid content and melt index as follows. The melt index is 190 ℃,
It is a value measured with a 2.16 kg load. EEA-A: Ethyl acrylate content 25Wt%, melt index 200g / 10min EEA-B: Ethyl acrylate content 10Wt%, melt index 150g / 10min EEA-C: Ethyl acrylate content 25Wt%, melt index 150g / 10min EEA-D: Ethyl acrylate content 5Wt%, melt index 100g / 10min EEA-E: Ethyl acrylate content 30Wt%, melt index 150g / 10min EEA-F: Ethyl acrylate content 25Wt%, melt index 10g / 10min EEA-G: Ethyl acrylate content 10Wt%, melt index 30g / 10min EEA-H: Ethyl acrylate content 5Wt%, melt index 20g / 10min EEA-I: Ethyl acrylate content 30Wt%, melt index 40g / 10min EEA-J: Ethyl acrylate content 4Wt%, melt index 150g / 10min EEA-K: Acrylic Ethyl acrylate content 37 Wt%, melt index 150 g / 10 min EEA-L: Ethyl acrylate content 20 Wt%, melt index 90 g / 10 min EEA-M: Ethyl acrylate content 4 Wt%, melt index 20 g / 10 min EEA-N: Ethyl acrylate content 37Wt%, melt index 20g / 10min EEA-O: Ethyl acrylate content 20Wt%, melt index 50g / 10min

Examples 1 to 15 Polypropylene type copolymer ("Nisseki Polypro J650"
G "(trade name of Nippon Petrochemical Co., Ltd.) (PP in the table
(Abbreviated) to an ethylene-ethyl acrylate copolymer were dry-blended, and then the mixture was fed to a coaxial twin-screw extruder having a screw diameter of 30 mm and a cylinder temperature of 230 ° C., and granulated after extrusion. Test pieces were prepared from the granulated resin by injection molding, and the impact resistance, heat resistance, coating adhesion, recoatability, tilt recoatability and appearance were examined. The results are shown in Tables 1, 2 and 3.

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

Examples 16 to 21 A thermoplastic elastomer ("EPO2P" (trade name of Japan Synthetic Rubber Co., Ltd.)) (abbreviated as EPO2P in the table) was further added to the polypropylene polymer (1). Each test piece was prepared in the same manner as in Example 1, and each test was performed. Table 4 shows the composition of each test piece and the test results.

[0032]

[Table 4] (Note) NB in the table means that no fracture occurred.

Examples 22 to 27 Each test piece was prepared in the same manner as in Example 1 except that talc was added as an inorganic filler to the resin compositions of Examples 16 to 21, and each test was conducted. . Table 5 shows the composition of each test piece and the test results.

[0034]

[Table 5]

(Note 1) "LMS-200" (trade name, manufactured by Fuji Talc Industry Co., Ltd.), and is shown in parts by weight based on 100 parts by weight of the resin content. Comparative Examples 1 to 10 Each test piece was prepared and tested in the same manner as in Example 1 except that an ethylene-ethyl acrylate copolymer outside the range specified in the present invention was added. Tables 6 and 7 show the compounding composition of each test piece and the test results.

[0036]

[Table 6]

[0037]

[Table 7]

From the above, the specific ethylene-ethyl acrylate copolymer in the polypropylene polymer, or the thermoplastic resin composition of the present invention in which the thermoplastic elastomer or the inorganic filler is further dispersed is It is clear that the composition of Comparative Example has poor coatability and insufficient performance, while the composition has excellent properties, heat resistance, coatability and moldability.

[0039]

EFFECT OF THE INVENTION The thermoplastic resin composition according to the first aspect of the present invention is excellent in paintability, particularly in adhesion and recoatability, while maintaining properties such as mechanical properties. The thermoplastic resin composition according to the second invention can improve mechanical properties such as impact resistance while maintaining the characteristics of the first invention. The thermoplastic resin composition according to the third invention can impart excellent heat resistance while maintaining the characteristics of the first or second invention. The resin molded product according to the fourth invention can be easily molded from the thermoplastic resin composition of the first, second or third invention, and is particularly preferably used as a bumper for automobiles.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display area C08L 23:08 101: 00)

Claims (4)

[Claims] 1. The polypropylene-based polymer (1) is 80-
99.5 wt% and ethyl acrylate 5 to 35 wt%
Content and melt index value of 100g / 10
containing ethylene-ethyl acrylate copolymer (2) of min or more and ethyl acrylate in an amount of 5 to 35% by weight,
And an ethylene-ethyl acrylate copolymer (3) having a melt index value of 40 g / 10 min or less, the ethylene-ethyl acrylate copolymer (2) and the ethylene-ethyl acrylate copolymer (3) Is 0.5 to 20% by weight, and the ratio of ethylene-ethyl acrylate copolymer (3) to ethylene-ethyl acrylate copolymer (2) is 1 to 99% by weight. Plastic resin composition. 2. A thermoplastic resin composition containing the thermoplastic resin composition according to claim 1 and a thermoplastic elastomer. 3. A thermoplastic resin composition comprising the thermoplastic resin composition according to claim 1 or 2 further dispersed with an inorganic filler. 4. A resin molded product obtained by molding the thermoplastic resin composition according to claim 1, 2 or 3 into a predetermined shape.