JPH0948889A - Resin composition excellent in coating property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject resin composition good in adhesion of films without requiring surface treatment such as primer coating or plasma irradiation. SOLUTION: This resin composition excellent in coating properties comprises (a) 35-80wt.% propylene homopolymer or propylene-ethylene copolymer, (b) 10-45wt.% ethylene-α-olefin copolymer rubber (with the proviso that ethylene is not included), (c) 0-20wt.% inorganic filler and (d) 5-20wt.% styrene-ethylene/ propylene block copolymer having 50-200g/10min melt flow rate(MFR), 10-60wt.% styrene content and 0.89-0.95 specific gravity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition having excellent coatability, and in particular, a resin composition which does not require surface treatment such as primer coating or plasma irradiation and has good coating film adhesion and excellent coatability. Regarding things.

[0002]

2. Description of the Related Art Since polypropylene is lightweight and has excellent mechanical strength and the like, it is widely used in various industrial fields such as interior and exterior parts of automobiles and home electric appliances. . However, since polypropylene is a non-polar polymer, there is a problem that the secondary processability, particularly the adhesion in a solid state with a polar coating material is low and the coating property is poor.

For the purpose of improving the adhesion between polypropylene and a coating film, a polypropylene resin is used as a copolymer of a styrene monomer-unsaturated dicarboxylic acid anhydride, or a copolymer of the copolymer is modified with a rubber. A method of adding a combination or a mixture thereof, a block copolymer of an aromatic vinyl compound and a conjugated diene compound, and the like is disclosed (JP-A-4-11643). However, this method
Before coating, it is necessary to perform a degreasing cleaning treatment with a halogen-based organic solvent such as 1,1,1-trichloroethane, and then perform a plasma treatment in order to introduce polar groups onto the surface of the base material. Such a halogen-based organic solvent has a problem that it has an adverse effect on the human body and the environment. In addition, the plasma processing complicates the working process and is uneconomical in terms of time.

A method of applying a primer coating instead of such a plasma treatment is known, but this method complicates the working process and requires a large amount of an organic solvent, resulting in a high manufacturing cost. There is a problem.

Therefore, an object of the present invention is to provide a resin composition which does not require a surface treatment such as primer coating or plasma irradiation and which has good coatability and excellent coatability.

[0006]

As a result of earnest research in view of the above problems, the present inventors have found that a propylene homopolymer or a propylene-ethylene copolymer, an ethylene / α-olefin copolymer rubber, and an inorganic filler. By blending a specific styrene-ethylene / propylene block copolymer with the resin component consisting of, there is no need for surface treatment such as primer coating or plasma irradiation, and excellent coating properties with good adhesion of the coating film. Found that a resin composition that
The present invention was conceived.

That is, the resin composition having excellent coatability of the present invention comprises (a) 35 to 80% by weight of a propylene homopolymer or propylene-ethylene copolymer, and (b) ethylene / α.
-Olefin (excluding ethylene) copolymer rubber 10 to 45% by weight, and (c) inorganic filler 0 to 20% by weight
And (d) a styrene-ethylene / propylene block copolymer having a melt flow rate of 50 to 200 g / 10 minutes, a styrene content of 10 to 60% by weight, and a specific gravity of 0.89 to 0.95. It consists of and.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. [1] Each component of resin composition having excellent coatability (a) Propylene homopolymer or propylene-ethylene copolymer Melt flow rate of propylene homopolymer used in the present invention (MFR, 230 ° C., load 2.16 kg) (Measured with)
Is from 1 to 120 g / 1 from the viewpoint of moldability and impact resistance.
0 minutes is preferable, and 10 to 90 g / 10 minutes is more preferable.

The method for producing the propylene homopolymer is not particularly limited, but a polymerization method using a stereoregular catalyst is preferable. As the stereoregular catalyst, titanium trichloride, titanium tetrachloride, titanium halide compounds such as trichloroethoxy titanium, transition metal components such as a contact product of the titanium halide compound and a magnesium compound represented by magnesium halide. Alkylaluminum compounds or their binary catalysts with organometallic components such as halides, hydrides, alkoxides, etc., and electron donating compounds containing nitrogen, phosphorus, sulfur, oxygen, silicon, etc. added to these components 3 Component type catalysts may be mentioned.

The polymerization reaction of propylene homopolymer is
It may be performed in either a gas phase or a liquid phase. For example, when polymerizing in a liquid phase, it can be carried out in an inert hydrocarbon such as n-butane, isobutane, n-pentane, isopentane, hexane, heptane, octane, cyclohexane, benzene, toluene, xylene or a liquid monomer. . The polymerization temperature is usually −80 to 150 ° C., preferably 4
0-120 ° C. The polymerization pressure is preferably 1 to 60 atm, and the molecular weight of the resulting polymer can be adjusted with hydrogen or other known molecular weight regulators. Polymerization is carried out by a continuous or batch reaction, and the conditions may be those usually used. Furthermore, the polymerization reaction may be carried out in one stage or in two stages.

The propylene-ethylene copolymer used in the present invention may be any of a block copolymer, a random copolymer and an alternating copolymer. From the viewpoint of moldability and impact resistance, the MFR of the propylene-ethylene copolymer is 1 to 1.
20 g / 10 minutes is preferable, and 10-90 g / 10 minutes is more preferable.

The method for producing the propylene-ethylene copolymer is also not particularly limited, but in the above-mentioned propylene polymerization, a propylene homopolymer is produced in the preceding stage, and then ethylene is added to produce a propylene-ethylene copolymer. Method or an ethylene homopolymer or a propylene-ethylene copolymer is produced in advance by the same production method as the propylene homopolymer, and this is mechanically mixed with the propylene homopolymer and the post-reactor blend. There are ways.

(B) Ethylene / α-olefin copolymer rubber Ethylene / α-olefin copolymer rubber is a copolymer rubber of ethylene and α-olefin other than ethylene, for example, ethylene-propylene copolymer. Rubber (EP
R) and ethylene obtained by copolymerizing this with a diene compound
Examples thereof include propylene-diene copolymer rubber (EPDM) and ethylene-butene copolymer rubber (EBR).

Specifically, the ethylene-propylene copolymer rubber (EPR) preferably has an ethylene content of 50 to 90 mol% and a propylene content of 50 to 10 mol%. A more preferable range is that the ethylene content is 70 to 80 mol% and the propylene content is 30 to 20 mol%. In the case of ethylene-propylene-diene copolymer rubber (EPDM), examples of the diene compound include ethylidene norbornene, dicyclopentadiene and 1,4-hexadiene. Ethylene-propylene copolymer rubber (ethylene-propylene-
(Including diene copolymer rubber) has an MFR of 0.5 to 20.
g / 10 minutes is preferable, and 0.5-10 g / 10 minutes is more preferable.

Further, ethylene-butene copolymer rubber (EB
R) has an ethylene content of 70 to 85 mol%,
The butene-1 content is preferably 30 to 15 mol%. A more preferable range is that the ethylene content is 75 to
It is 85 mol% and the content of butene-1 is 25 to 15 mol%. Ethylene-butene copolymer rubber (EBR)
The MFR of 1 to 30 g / 10 minutes is preferable, and 1 to 20
g / 10 minutes is more preferable. Such an EBR may contain, in addition to ethylene and butene-1, a small amount of other α-olefins such as hexene-1, octene-1 and diene compounds such as ethylidene norbornene and dicyclopentadiene.

The ethylene / α-olefin copolymer rubber as described above may be used alone or
You may mix and use 1 or more types suitably.

(C) Inorganic filler The inorganic filler used in the present invention is generally used as a filler and a reinforcing material for resins and the like, and examples thereof include talc, mica, fiber crystalline calcium silicate and calcium carbonate. Can be mentioned. Of these, talc is particularly preferable. It is preferable to use an inorganic filler having an average particle diameter of 15 μm or less. In the case of needle-like or fibrous substances, those having a fiber diameter of 1 to 100 μm and an aspect ratio of 3 to 30 are preferable.

(D) Styrene-ethylene / propylene block copolymer The styrene-ethylene / propylene block copolymer used in the present invention is represented by the following general formula (I). (S-EP) _n -S _m ··· (I) (where S is a block of a polymer of a monovinyl-substituted aromatic hydrocarbon, EP is an ethylene / propylene moiety, and n is 1 to 20). It is an integer and m is 0 or 1.)

Such a styrene-ethylene / propylene block copolymer is prepared at 25-175 ° C. in the presence of a catalyst obtained by reducing a styrene-isoprene block copolymer with a cobalt or nickel alkoxide with an alkylaluminum compound. By hydrogenating at a temperature, only the isoprene portion is selectively hydrogenated to form a structure corresponding to an ethylene / propylene copolymer.

In the styrene-ethylene / propylene block copolymer, it is not necessary that all isoprene moieties be hydrogenated, and 5% or more may be hydrogenated. The hydrogenation ratio is preferably 50% or more, more preferably 80% or more.

The content of the block of the monovinyl-substituted aromatic hydrocarbon polymer in the styrene-ethylene / propylene block copolymer is 10 to 60% by weight, preferably 10 to 40% by weight. When the content of the block of the polymer of monovinyl-substituted aromatic hydrocarbon is less than 10% by weight, heat resistance and the like are low, while when it exceeds 60% by weight, the coating property is deteriorated.

The specific gravity of the styrene-ethylene / propylene block copolymer is 0.89 to 0.95, preferably 0.89 to 0.93. When the specific gravity of the styrene-ethylene / propylene block copolymer is less than 0.89, the heat resistance is low, while when it exceeds 0.95, the impact resistance is lowered.

Further, the melt flow rate of styrene-ethylene / propylene block copolymer (MFR, 200
C., load 10 kg) 50-200 g / 10 minutes,
It is preferably 50 to 150 g / 10 minutes. MFR is 5
If it is less than 0 g / 10 minutes, the moldability is low, while it is 200 g / 1.
If it exceeds 0 minutes, the mechanical strength decreases.

Further, the number average molecular weight of the styrene-ethylene / propylene block copolymer is preferably 10,000 to 200,000, more preferably 50,000 to 100,000.

By adding such a styrene-ethylene / propylene block copolymer to the resin, the impregnating property of the organic solvent in which the coating material is dispersed into the resin molded product is increased, so that the coating property is improved. You can

[2] Blending Ratio The blending ratio of each component of the resin composition as described above is 35 to 80% by weight, preferably 40 to 60% by weight of propylene homopolymer or propylene-ethylene copolymer. , Ethylene / α-olefin copolymer rubber 10-4
5% by weight, preferably 20-40% by weight, inorganic filler 0-20% by weight, preferably 5-15% by weight, styrene-ethylene / propylene block copolymer 5-20% by weight, preferably Is 5 to 15% by weight.

When the blending amount of the propylene homopolymer or propylene-ethylene copolymer is less than 35% by weight, the ductility and hardness of the resulting composition are low, while when it exceeds 80% by weight, the impact resistance is lowered. When the ethylene / α-olefin copolymer rubber is less than 10% by weight, the tensile strength is low,
On the other hand, when it exceeds 45% by weight, moldability and heat resistance are deteriorated. On the other hand, if the content of the inorganic filler exceeds 20% by weight, the impact resistance decreases. Furthermore, when the blending amount of the styrene-ethylene / propylene block copolymer is less than 5 parts by weight,
The effect of improving the paintability is not sufficient, and even if it exceeds 20 parts by weight, the effect of improving the paintability commensurate with it is not observed.

[3] Other Components The resin composition of the present invention having excellent coatability has other additives such as a heat stabilizer, an antioxidant, a light stabilizer and a hard stabilizer for the purpose of modifying the resin composition. A flame retardant, a plasticizer, an antistatic agent, a release agent, a foaming agent, a coloring agent, a pigment and the like can be added.

[4] Method for producing resin composition having excellent coatability The resin composition having excellent coatability of the present invention is prepared by mixing the above components using a Henschel mixer, a super mixer, a ribbon blender, etc., and then performing uniaxial extrusion. It can be obtained by melt-kneading in a temperature range of 180 to 230 ° C. with a machine, a twin-screw extruder, a Banbury mixer, a kneader or the like.

[0030]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples, but the present invention is not limited thereto. Examples 1-9 and Comparative Examples 1-5 1. Raw material (a) Propylene homopolymer or propylene-ethylene copolymer PP1: Propylene-ethylene block copolymer MFR = 25g / 10min (measured at 230 ° C, load 2.16kg) Cold xylene soluble portion ratio = 13% by weight PP2: Propylene-ethylene block copolymer MFR = 40g / 10min Proportion of cold xylene soluble part = 13% by weight (b) Ethylene / α-olefin copolymer rubber EPR1: Ethylene-propylene copolymer rubber (EP02P, Japan Synthetic rubber Co., Ltd.) MFR = 3.2g / 10min Ethylene content = 74mol% EPR2: Ethylene-propylene copolymer rubber (EP07P, manufactured by Nippon Synthetic Rubber Co., Ltd.) MFR = 0.7g / 10min Ethylene content = 73 mol% (c) Inorganic filler Talc: LMR100 (manufactured by Fuji Talc Co., Ltd.) Average particle size = 2 μm (d) Styrene-ethylene / propylene block copolymer SEPS: Styrene content = 30 wt% MFR = 100 g / 10min (measured at 200 ℃, load 10kg) ) Specific gravity = 0.93

2. Kneading and molding method The above raw materials were blended in the proportions shown in Tables 1 and 2, and dry blended using a super mixer, and then 200 r at 200 ° C with a twin-screw extruder (PCM-45 manufactured by Ikegai Corp.).
The mixture was melt-kneaded at a screw rotation speed of pm and extruded to obtain pellets. The pellets thus obtained were injection-molded with an injection molding machine at a resin temperature of 210 ° C., an injection pressure of 650 kg / cm ² and a mold temperature of 50 ° C. to prepare test pieces.

3. Physical property measurement Physical property measurement of each test piece was performed by the following methods. The results are shown in Tables 1 and 2 below. (1) Tensile strength (kg / cm ² ): Measured at room temperature according to ASTM D638. (2) Tensile elongation at break (%): Measured at room temperature according to ASTM D638. (3) Flexural modulus (kg / cm ² ): Measured at room temperature according to ASTM D790. (4) Flexural strength (kg / cm ² ): Measured at room temperature according to ASTM D790. (5) Izod impact strength (kgcm / cm): Measured at -30 ° C with a notch using a 3.2 mm thick test piece according to ASTM D256. (6) Heat distortion temperature (℃): 18.6kg / cm ^{2 according} to ASTM D648
The pressure was measured. (7) Rockwell hardness (scale R): Measured according to ASTM D785. (8) Brittleness temperature (° C): Measured by ASTM D746. (9) Adhesion: Wipe the test piece with gauze containing isopropyl alcohol, apply a paint with a solid content of 30%, and apply 30% at 80 ° C.
A coating film was formed by baking for minutes. The adhesive strength (primary adhesive strength) after leaving the obtained coated molded article for 24 hours or more under the conditions of 23 ° C. and 50% humidity was evaluated by the edge peeling test according to JIS D0202 4.15. The adhesion strength (secondary adhesion strength) of the coating film after being immersed in warm water at 40 ° C for 240 hours was also evaluated. ◯: Peeling does not occur at all. X: Peeling occurred even a little.

Table 1 Example No. 1 2 3 4 5 composition (wt%) PP1 55 50 45 60 40 PP2 ─ ─ ─ ─ ─ EPR1 30 30 30 30 20 40 EPR2 ─ ─ ─ ─ Talc 10 10 10 10 10 SEPS 5 10 15 10 10 Composition characteristics Tensile strength (kg / cm ² ) 178 173 167 182 160 Tensile elongation at break (%) 660 690> 700 600> 700 Flexural modulus (kg / cm ² ) 9300 8800 8000 10000 7000 Bending strength (kg / cm ² ) 200 195 189 206 180 Izod impact strength ⁽¹⁾ 8.5 16 NB 6.2 NB Heat distortion temperature (℃) 96 93 90 97 88 Rockwell hardness (R) 33 30 28 35 20 Embrittlement temperature (℃) -42 -46 -50- 39 -55 Primary adhesion strength ○ ○ ○ ○ ○ Secondary adhesion strength ○ ○ ○ ○ ○ Note (1) Unit: kg ・ cm / cm.

Table 1 (continued) Example No. 6 7 8 9 Composition (% by weight) PP1 ─ 50 55 45 PP2 50 ─ ─ ─ EPR1 30 ─ 30 30 EPR2 ─ 30 ─ talc 10 10 5 15 SEPS 10 10 10 10 Characteristic tensile strength of composition (kg / cm ² ) 174 173 171 179 Tensile elongation at break (%) 500 690 660 300 Flexural modulus (kg / cm ² ) 8900 8700 8500 9300 Bending strength (kg / cm ² ) 196 194 193 201 Izod impact strength 14 16 18 8.7 Thermal deformation Temperature (℃) 93 92 89 96 Rockwell hardness (R) 30 30 32 30 Embrittlement temperature (℃) -44 -45 -45 -40 Primary adhesion strength ○ ○ ○ ○ Secondary adhesion strength ○ ○ ○ ○

Table 2 Comparative Example No. 1 2 3 4 5 composition (wt%) PP1 50 60 70 ─ 60 PP2 ─ ─ ─ 60 ─ EPR1 40 30 20 30 ─ EPR2 ─ ─ ─ ─ 30 Talc 10 10 10 10 10 SEPS ─ ─ ─ ─ ─ Composition characteristics Tensile strength (kg / cm ² ) 175 180 186 181 178 Tensile elongation at break (%) 660 650 430 500 660 Flexural modulus (kg / cm ² ) 8500 10000 11500 10500 10000 Bending strength (kg / cm ² ) 195 205 216 204 206 Izod impact strength ⁽¹⁾ 15 6.5 4.5 6 7.5 Heat distortion temperature (℃) 88 95 101 94 96 Rockwell hardness (R) 28 32 36 33 31 Brittle temperature (℃) -45 -40 -34 -37- 42 Primary adhesion strength × × × × × Secondary adhesion strength × × × × × Note (1) Unit: kgcm / cm.

As is apparent from Tables 1 and 2, Example 1
The resin compositions of Nos. 9 to 9 are excellent in impact resistance, heat resistance and the like and have good coating film adhesion, but Comparative Examples 1 to 5
The resin composition (1) has inferior adhesion to the coating film.

[0037]

As described in detail above, the resin composition having excellent coatability of the present invention is a propylene homopolymer or a propylene-ethylene copolymer and an ethylene / α-olefin (provided that ethylene is not included). No) Since it consists of a copolymer rubber, an inorganic filler, and a specific styrene-ethylene / propylene block copolymer, there is no need for surface treatment such as primer coating or plasma irradiation, and the adhesion of the coating film is good. is there. Such a resin composition having excellent coatability of the present invention can be applied to various uses, but is particularly suitable for automobile exterior parts such as bumpers and side moldings.

Claims (1)

[Claims] 1. (a) 35 to 80% by weight of propylene homopolymer or propylene-ethylene copolymer, and (b) 10 to 45% by weight of ethylene / α-olefin (excluding ethylene) copolymer rubber. %, (C) inorganic filler 0 to 20
% By weight, and (d) a melt flow rate of 50 to 200 g / 10 minutes, a styrene content of 10 to 60% by weight,
Styrene-ethylene with a specific gravity of 0.89 to 0.95
A resin composition having excellent coatability, which comprises 5 to 20% by weight of a propylene block copolymer.