JP2001114957A - High-flowability thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition which can be produced safely and stably, has high flowability and low gloss, and is excellent in surface hardness. SOLUTION: This composition is prepared by compounding (A) 50-99 wt.% polypropylene resin with (B) 1-40 wt.% ethylene-α-olefin random copolymer having a density of 0.85-0.90 g/cm3, an MFR (190 deg.C, 2160 g load) of 100-10,000 g/10 min, and an ethylene content of 5-40 wt.%, (C) 0-40 wt.% ethylene-α-olefin random copolymer having an MFR lower than 100, and (D) 0-40 wt.% inorganic filler.

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 having high flow, low gloss and excellent surface hardness. More specifically, the present invention relates to a thermoplastic resin composition mainly composed of polypropylene, which can be suitably used for injection molded articles (including injection compression molded articles) such as interior and exterior parts of automobiles.

[0002]

2. Description of the Related Art Polypropylene is widely used in various fields because of its low cost, low density, but good heat resistance, rigidity and moldability. However, since the impact resistance is inferior, ethylene-propylene block copolymer obtained by multi-stage polymerization for the purpose of improvement
Various polypropylene resin compositions to which a rubber component such as a propylene copolymer or an ethylene / butene copolymer and an inorganic filler such as talc are added have been proposed.

[0003] These resin compositions are used as molding materials for various industrial parts such as automobile interior / exterior parts such as bumpers, instrument panels and garnishes, and home electric appliance parts such as TV cases. In recent years, these products have been reduced in thickness, function, and size, and therefore, higher performance of materials is required. In particular, in order to increase the size of a product, it is desired to improve the molding performance by increasing the fluidity of the material.

However, in order to achieve high fluidity of the material,
When the flowability of the raw material polypropylene or rubber component is improved, the flowability of the material is improved, but the surface hardness is reduced and the surface gloss is increased. In particular, when used for instrument panels, the deterioration of scratch resistance due to a decrease in surface hardness causes a problem in the durability of the product. Had the problem of getting worse. Therefore, conventionally, the surface hardness has been improved by painting the instrument panel surface, and the glossiness has been reduced.

On the other hand, as an attempt to achieve high fluidity, modification of a resin with an organic peroxide has been attempted.
For example, in JP-A-10-87919, a highly fluid material is obtained by dynamically heat-treating a polypropylene, an amorphous or low-crystalline α-olefin copolymer, an inorganic filler and an organic peroxide. ing. However, there is a problem that it is difficult to ensure safety in the modification operation using an organic peroxide because it handles dangerous substances, and the fluidity greatly varies depending on the modification conditions. For this reason, production can be carried out safely and stably,
In addition, development of a thermoplastic resin composition having good fluidity, low gloss, and excellent surface hardness has been desired.

[0006]

The object of the present invention is to provide a thermoplastic resin composition, particularly a polypropylene resin composition, which can be produced safely and stably, has high flow, low gloss and excellent surface hardness. Make it an issue.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in view of the above-mentioned problems, and as a result, by blending a polypropylene resin, a specific ethylene / α-olefin random copolymer and, in some cases, an inorganic filler. The present inventors have found that the above-mentioned problems can be solved, and have completed the present invention.

That is, the present invention provides the following components (A) to
The present invention relates to a thermoplastic resin composition containing (D). (A) a polypropylene resin; 50 to 99% by weight; (B) a density of 0.85 to 0.90 g / cm ³ , and a melt flow rate (MFR: 190 ° C. under a load of 2160 g) of 100 to 10000 g / 10 min. Ethylene / α-olefin random copolymer having an ethylene content of 5 to 40% by weight; 1 to 40% by weight (C) MFR (at 190 ° C. under a load of 2160 g) of 100
0 to 40% by weight (D) inorganic filler; 0 to 40% by weight

[0009] The present invention also relates to the present invention, wherein the ethylene / α-olefin random copolymer of the component (B) comprises ethylene and
The present invention relates to the above-mentioned thermoplastic resin composition, which is a copolymer with a kind of α-olefin having 3 to 12 carbon atoms.

[0010] The present invention also provides the thermoplastic resin composition, wherein the content of at least one α-olefin in the ethylene / α-olefin random copolymer of the component (B) is 5 to 80% by weight. About.

The present invention also relates to the present invention, wherein the ethylene / α-olefin random copolymer of the component (B) is a terpolymer of ethylene, an α-olefin having 3 carbon atoms and an α-olefin having 4 carbon atoms. The present invention relates to the above-mentioned thermoplastic resin composition.

Further, the present invention relates to the thermoplastic resin composition, wherein the inorganic filler (D) is talc having an average particle size of 10 μm or less. Further, the present invention relates to a molded article obtained by molding the thermoplastic resin composition.

[0013]

Embodiments of the present invention will be described below. The thermoplastic resin composition of the present invention comprises a polypropylene resin (component (A)) and ethylene
It contains an α-olefin random copolymer (component (B)) and optionally further contains a new ethylene / α-olefin random copolymer (component (C)) and an inorganic filler (component (D)). Is also good.

(1) Polypropylene resin (component (A)) The polypropylene resin (A) used in the present invention comprises:
Propylene homopolymer (homopolypropylene resin),
Alternatively, a copolymer of propylene and a small amount of another polymerizable monomer (comonomer) may be used. Examples of the comonomer include ethylene and α-olefins having 4 to 10 carbon atoms. Specifically, 1-butene, 1-pentene, 4-
Methyl-1-pentene, 1-hexene, 1-octene and the like can be mentioned. Among them, a propylene / ethylene copolymer (ethylene content of about 0.1 to 5.0% by weight) is particularly desirable from the viewpoint of physical property balance and cost.

The propylene / ethylene copolymer is preferably synthesized by multi-stage polymerization. In multistage polymerization, first, propylene is polymerized in the presence of a Ziegler catalyst or the like to produce a crystalline propylene homopolymer portion (which may contain a small amount of a comonomer component). The mixture is switched to produce a propylene / ethylene copolymer portion.

The propylene / ethylene block copolymer synthesized by the multi-stage polymerization is substantially composed of a crystalline homopolypropylene portion, a propylene / ethylene copolymer portion, and a small amount of a crystalline homopolyethylene portion. Yes, each part may be present as a single polymer, or each may be in a linked state. Each of the above parts is basically composed of propylene and / or ethylene.
-Olefins, such as 1-butene, 1-pentene, 4-
Methyl-1-pentene, 1-hexene, 1-octene, diene-based monomers, and the like may be contained in small amounts.

The above polypropylene resin can be produced by various methods. Among them, a preferable method is, for example, production by applying a known slurry polymerization method, a solution polymerization method, a liquid phase polymerization method using an olefin monomer as a medium, and a gas phase polymerization method in the presence of a stereoregular catalyst. Can be. As the polymerization catalyst, a Ziegler-Natta catalyst, a metallocene catalyst, or the like can be used. From the viewpoint of the balance between the fluidity and the physical properties of the resin composition, the MFR of the polypropylene resin is preferably from 10 to 200 g / 10 minutes, and
0 to 150 g / 10 min is particularly preferred.

(2) Ethylene / α-olefin random copolymer (component (B)) The resin composition of the present invention comprises an ethylene / α-olefin random copolymer (B) having the following specific physical properties. ) As an essential component.

(I) Density The density of the ethylene / α-olefin random copolymer (B) used in the present invention is 0.85 to 0.90 g /
cm ³ , preferably 0.86 to 0.88 g / cm ³
It is. Ethylene α with density less than 0.85 g / cm ³
-Use of the olefin random copolymer (B) results in only a thermoplastic resin composition having insufficient hardness and a density of the ethylene / α-olefin random copolymer (B) exceeding 0.90 g / cm ^3. Using ()), only a thermoplastic resin composition having insufficient impact resistance can be obtained.

(Ii) Melt flow rate The ethylene / α-olefin random copolymer (B)
Has an MFR (190 ° C., 2160 g load) of 100 to 1
0000 g / 10 min, preferably 130 to 800
0 g / 10 minutes. If the MFR is less than 100 g / 10 minutes, the improvement in fluidity is small, and if it exceeds 10,000 g / 10 minutes, the surface hardness is undesirably reduced.

(Iii) Ethylene content The ethylene / α-olefin random copolymer (B)
Has an ethylene content of 5 to 40% by weight, preferably 7
３０30% by weight. If the ethylene content is less than 5% by weight, the performance as a rubber is not exhibited, and if it exceeds 40% by weight, the gloss increases, which is not preferable.

The ethylene / α-olefin random copolymer (B) is a random copolymer of ethylene and two kinds of α-olefins having 3 to 12 carbon atoms, more preferably 4 to 12 carbon atoms. Is desirable. Such α-
Specific examples of the olefin include 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, and 1-butene.
Dodecene and the like. Further, it is preferable to use two kinds of α-olefins, and among them, a random copolymer of ethylene and two kinds of α-olefins having 3 and 4 carbon atoms, that is, an α-olefin having ethylene and 3 carbon atoms And a terpolymer of α-olefin having 4 carbon atoms. Further, it is desirable that at least one kind (preferably propylene) of the α-olefin is 5 to 80% by weight, preferably 7 to 75% by weight. In particular, Part 2
It is desirable that each kind of α-olefin is 5 to 80% by weight, preferably 7 to 78% by weight.

The ethylene / α-olefin random copolymer (B) can be polymerized using a known titanium-based catalyst, vanadium-based catalyst or metallocene catalyst, but can be polymerized using a metallocene catalyst. desirable.

(3) Ethylene / α-olefin random copolymer (component (C)) In the present invention, in addition to the ethylene / α-olefin random copolymer (component (B)), if necessary, Further, a new ethylene / α-olefin random copolymer having the following physical properties can be blended.

(I) Density The density of the ethylene / α-olefin random copolymer (C) used here is preferably 0.85 to 0.90 g.
/ Cm ³ , more preferably 0.86 to 0.88
g / cm ³ . From the ethylene / α-olefin random copolymer having a density of less than 0.85 g / cm ³ , only a thermoplastic resin composition having insufficient hardness can be obtained, and the density is 0.9.
From an ethylene / α-olefin random copolymer exceeding 0 g / cm ³ , only a thermoplastic resin composition having insufficient impact resistance can be obtained.

(Ii) Melt flow rate The ethylene / α-olefin random copolymer (C)
Has an MFR (190 ° C., 2160 g load) of less than 100, preferably 0.1 to 95 g / 10 min, more preferably 0.5 to 80 g / 10 min. MFR
If it is 100 g / 10 min or more, the surface hardness is undesirably reduced.

(Iii) Ethylene content The ethylene / α-olefin random copolymer (C)
Has an ethylene content of 40 to 90% by weight, preferably 45 to 85% by weight. If the ethylene content is less than 40% by weight, the performance as a rubber is not exhibited, and 90% by weight
Exceeding the gloss is not preferred because the gloss becomes high. The ethylene / α-olefin random copolymer (C) is desirably a random copolymer of ethylene and two kinds of α-olefins having 4 to 12 carbon atoms. Such α-
Specific examples of the olefin include 1-butene, 1-hexene, 1-heptene, 1-octene, 1-decene, and 1-butene.
Dodecene and the like.

The ethylene / α-olefin random copolymer (C) can be polymerized using a known titanium catalyst, vanadium catalyst or metallocene catalyst, but can be polymerized using a metallocene catalyst. desirable.

(4) Inorganic filler (component (D)) As the inorganic filler (D) used in the present invention, specifically, talc, calcium carbonate, glass fiber, basic magnesium sulfate whisker, calcium titanate Whiskers, aluminum borate whiskers, mica and the like. Among them, talc is preferred.

The talc preferably used in the present invention has an average particle size of 10 μm or less, preferably 5 μm or less. The average talc particle size can be measured by a laser diffraction scattering method. In the present invention, among such talcs, talc having an average aspect ratio (ratio of length or thickness in either the vertical or horizontal direction) of 4 or more, preferably 5 or more is used. The measurement of the aspect ratio of talc is obtained from a value measured by a microscope or the like.

The talc is first produced by, for example, pulverizing raw talc with an impact mill or a micron mill type pulverizer, or finely pulverizing it with a micron mill or jet mill, and then using a cyclone or a micron separator. It is manufactured by a method such as classification adjustment.

The talc may be untreated or surface-treated in advance. Surface treatment is preferred because the rigidity and heat resistance of the composition can be improved. Specific examples of the surface treatment include a chemical or physical treatment using a treating agent such as a silane coupling agent, a higher fatty acid, a fatty acid metal salt, an unsaturated organic acid, or an organic titanate.

The method of surface treatment of talc using a metal salt is not particularly limited, and examples thereof include a method of mixing talc powder, which has been pulverized and classified in advance, and a predetermined amount of a metal salt with a high-speed mixer. When kneading and granulating the composition, a method may be used in which the metal salt and talc powder are blended and mixed with other polypropylene or the like, and the mixture is provided to a granulator. Further, the above-mentioned inorganic fillers may be used alone or as a mixture of several kinds.

(5) Other Ingredients The thermoplastic resin composition of the present invention may contain other additives, for example, a heat stabilizer, an oxidant, etc. for the purpose of other modification depending on its use such as interior and exterior materials of automobiles. An inhibitor, a light stabilizer, a flame retardant, a granulating agent, a plasticizer, an antistatic agent, a copper damage inhibitor, a release agent, a foaming agent, a coloring agent, a pigment and a dispersant thereof can be added. The above-mentioned various additives and pigments are generally added when each component is mixed. However, a high-concentration master batch may be prepared in advance and then blended after injection or extrusion.

(6) Mixing ratio of each component The mixing ratio of each of the above components is such that the polypropylene resin (A) is 50 to 99% by weight, preferably 60 to 95% by weight, based on the total amount of the resin composition. The α-olefin random copolymer (B) is 1 to 40% by weight, preferably 3% by weight.
0 to 30% by weight, and the ethylene / α-olefin random copolymer (C) is 0 to 40% by weight, preferably 3 to 3% by weight.
0% by weight, the inorganic filler (D) is 0 to 40% by weight,
Preferably it is 5 to 30% by weight.

When the content of the polypropylene resin (A) is less than 50% by weight, the rigidity and heat resistance of the obtained thermoplastic resin composition are reduced.
Hardness tends to decrease, while if it exceeds 99% by weight, impact resistance decreases. If the ethylene / α-olefin random copolymer (B) is less than 1% by weight, the impact resistance is insufficient, while if it exceeds 40% by weight, the strength, rigidity, heat resistance, hardness and the like are reduced.

The ethylene / α-olefin random copolymer (C) may not be contained in the resin composition of the present invention, but may be added to the ethylene / α-olefin random copolymer (B). By further containing the ethylene / α-olefin random copolymer (C), there is an advantage that the impact resistance is further improved. However, when the ethylene / α-olefin random copolymer (C) exceeds 40% by weight, strength, rigidity, heat resistance, hardness and the like are reduced.

The inorganic filler (D) does not have to be incorporated in the resin composition of the present invention, but the presence of the inorganic filler (D) has the advantage of improving rigidity. . However, when the amount of the inorganic filler (D) exceeds 40% by weight, impact resistance and ductility decrease.

(7) Production of thermoplastic resin composition The thermoplastic resin composition of the present invention comprises the above components (A) to
(D) In some cases, other components are blended in the above blending ratio and kneaded using a normal kneader such as a single screw extruder, a twin screw extruder, a Banbury mixer, a roll mixer, a Brabender plastograph, or a kneader. Obtained by In this case, it is preferable to select a kneading method capable of uniformly dispersing the components, and usually kneading is performed using a twin-screw extruder. In this kneading, the compound of each of the above components may be kneaded at the same time or may be kneaded sequentially.

(8) Molding of thermoplastic resin composition The thermoplastic resin composition thus obtained is molded by injection molding (including gas injection molding) or injection compression molding (press injection). Accordingly, various molded products, particularly, interior and exterior parts of automobiles such as bumpers, instrument panels, and garnishes, and parts of home electric appliances such as TV cases can be obtained.

[0041]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the scope of the invention. In addition, the raw materials and test methods used in Examples and Comparative Examples are as follows.

1. Raw Materials (1) Polypropylene resin (component (A); abbreviated as “PP”) PP-1: crystalline ethylene containing 8% by weight of an ethylene / propylene random copolymer part and having an MFR of 50 g / 10 min for the whole component -A propylene block copolymer was used. PP-2: A crystalline ethylene / propylene block copolymer containing 8% by weight of an ethylene / propylene random copolymer part and having an MFR of 100 g / 10 min for the whole components was used.

(2) Ethylene / α-olefin random copolymer (B or C component) Each content of ethylene (C2), propylene (C3), butene-1 (C4) and octene (C8) shown in Table 1 density,
And an ethylene / α-olefin random copolymer having an MFR (190 ° C., 2160 g).

[0044]

[Table 1]

The manufacturers of the copolymers shown in Table 1 are as follows. Hüls: ERA-1 (VESTOPLAST891),
ERA-2 (VESTOPLAST708), ERA-3 (VESTOPLAST704), ERA-4
(VESTOPLAST608), manufactured by Dupont Dow: EOR-1 (ENGAGE8
400), EOR-2 (ENGAGE8100).

(3) Inorganic filler (D) Talc having an average particle size of 4.6 μm and an aspect ratio of 6 was used. (4) Other components Organic peroxide: P / O-1: 1,3-bis (t-butylperoxyisopropyl) benzene

2. Physical property measurement method (1) Based on MFR ASTM-D1238, temperature 230 ° C, load 21
Measured at 60 g. (2) Rockwell hardness Measured according to ASTM-D785 (scale is R). (3) Glossiness Measured according to JIS-K7105 (60 ° C, specular glossiness).

[0048]

Examples 1 to 5 and Comparative Examples 1 to 4 Each component (A) to (D)
And other components were blended at the ratios shown in Table 2, and after dry blending using a super mixer, raw materials were supplied from a hopper, and a high-speed twin-screw extruder (KCM, manufactured by Kobe Steel Ltd.) was used. The mixture was melt-kneaded and extruded to obtain pellets. The obtained pellets were subjected to an injection molding machine at a resin temperature of 21.
Injection molding was performed at 0 ° C. and a mold temperature of 30 ° C., and a physical property test piece was molded and evaluated. Table 2 shows the results. As shown in Table 2, the thermoplastic resin compositions having the compositions shown in Examples 1 to 5 all exhibited a good balance of physical properties. On the other hand, those shown in Comparative Examples 1 to 4 had poor physical property balance.

[0049]

[Table 2]

[0050]

The thermoplastic resin composition of the present invention has high fluidity, low gloss and excellent surface hardness.
Therefore, it is useful for products obtained by injection molding of industrial materials such as automotive interior / exterior parts and home electric parts.
In particular, it can be suitably used as a molding material for various industrial parts such as thinner, higher-performance, and larger-sized molded articles, for example, automobile parts such as bumpers, instrument panels, and garnishes, and household electric appliance parts such as TV cases. Can be.

Continued on the front page F term (reference) 4J002 BB05X BB05Y BB121 BB141 BB15X BB151 DE186 DE236 DG046 DJ046 DJ056 DK006 DL006 FA046 FA066 FA086 FD016 GN00 GQ01

Claims (6)

[Claims] 1. A thermoplastic resin composition comprising the following components (A) to (D). (A) a polypropylene resin; 50 to 99% by weight; (B) a density of 0.85 to 0.90 g / cm ³ , and a melt flow rate (MFR: 190 ° C. under a load of 2160 g) of 100 to 10000 g / 10 min. Ethylene / α-olefin random copolymer having an ethylene content of 5 to 40% by weight; 1 to 40% by weight (C) MFR (at 190 ° C. under a load of 2160 g) of 100
0 to 40% by weight (D) inorganic filler; 0 to 40% by weight 2. The ethylene / α-olefin random copolymer of the component (B) comprises ethylene and two kinds of carbon atoms having 3 carbon atoms.
The thermoplastic resin composition according to claim 1, wherein the thermoplastic resin composition is a copolymer with an α-olefin of (1) to (12). 3. The thermoplastic resin according to claim 1, wherein the content of at least one α-olefin in the ethylene / α-olefin random copolymer of the component (B) is 5 to 80% by weight. Composition. 4. The ethylene / α-olefin random copolymer of the component (B) is a terpolymer of ethylene, an α-olefin having 3 carbon atoms, and an α-olefin having 4 carbon atoms. The thermoplastic resin composition according to any one of claims 1 to 3, which is characterized in that: 5. An inorganic filler (D) having an average particle size of 10 μm
The thermoplastic resin composition according to any one of claims 1 to 4, which is the following talc. 6. A molded article obtained by molding the thermoplastic resin composition according to claim 1.