JP3338247B2 - Thermoplastic polymer composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a propylene / ethylene block copolymer, an ethylene / α-olefin copolymer resin and talc. The present invention relates to a thermoplastic polymer composition having excellent elastic modulus, heat resistance and surface hardness, which is suitable for injection molded articles such as interior parts for automobiles.

[0002]

2. Description of the Related Art Many attempts have been made to increase impact resistance and rigidity by adding an ethylene / propylene copolymer, various ethylene-based copolymers and talc to a polypropylene resin. JP-B-63-42929 having impact resistance, JP-A-64-150,
The compositions described in JP-A-64-66263 and JP-A-1-204946 are known. But,
In the composition described in JP-B-63-42929, a sufficiently high flexural modulus and heat resistance are not obtained because an exceptionally high crystalline polypropylene resin is not used. Also, JP-A-64-150 and JP-A-64-662
No. 63 and JP-A-1-204946, the compositions described in JP-A-1-204946 are suitable for applications requiring impact resistance such as bumpers due to the small amount of talc. For use in interior materials and the like, the flexural modulus was significantly insufficient, and was not practical. On the other hand, there is also known a composition described in Japanese Patent Publication No. 4-159345 in which an ethylene / α-olefin-based copolymer and a large amount of an inorganic filler are blended. It was not preferable from the viewpoint of chemical conversion.

[0003]

SUMMARY OF THE INVENTION The present invention solves such problems of the prior art, and has a high fluidity and impact resistance.
The present invention relates to a composition suitable for automobile interior parts, which can exhibit good physical properties in terms of rigidity and heat resistance, and is lightweight and excellent in moldability.

[0004]

The present inventors have conducted various studies to solve the above-mentioned problems, and as a result, have found that a propylene / ethylene block having a propylene homopolymer portion having high fluidity and extremely high crystallinity is obtained. By blending the polymer with talc at a specific ratio, an elastomeric copolymer containing a crystalline segment in the molecule, it exhibits high fluidity and good physical properties, is lightweight and can be molded. It has been found that an excellent composition is obtained.

That is, the thermoplastic polymer composition of the present invention comprises: (A) a component: a melt flow rate (230 ° C., 2.16 kg load) of more than 30 to 60 g / 10 min, and a propylene homopolymer portion; A propylene / ethylene block copolymer having a melt flow rate (230 ° C., 2.16 kg load) of more than 50 to 90 g / 10 min and an isotactic pentad fraction of 0.97 or more, having an ethylene content of 61 to 87 parts by weight of a propylene / ethylene block copolymer having a content of 2 to 8% by weight and an ethylene content of 30 to 50% by weight in the copolymer in the block copolymer (B) component: differential scanning It has a melting temperature of 60 to 100 ° C as measured by a calorimeter, a melt flow rate (230 ° C, 2.16 kg load) of 3 to 10 g / 10 minutes, and α-olefin Carbon number of emissions is an ethylene · alpha-olefin copolymer rubber having 4 to 8, a density of less than 0.9 g / cm ^3, and alpha-olefin content is 15 to 25 wt%, ethylene -Α-olefin copolymer rubber 5 to 15 parts by weight (C) component: 8 to 14 parts by weight of talc having an average particle size of 5 µm or less and a specific surface area of 3.5 m ² / g or more; ), (B) and (C) are combined such that the total weight of the components is 100 parts by weight, and the sum of the components (B) and (C) is 13 to 25 parts by weight. The physical properties of the composition formed by the method described above include a melt flow rate (230 ° C., 2.16 kg load) of 23 g / 10 min or more, a flexural modulus at 23 ° C. of 20,000 kg / cm ² or more, and an Izod impact value. Is 5 kg · cm / cm or more, Rockwell hardness 85 or more, and the low-temperature brittle temperature is equal to or is 15 ℃ less.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

[I] Constituents (a) Propylene / ethylene block copolymer (component (A)) The propylene / ethylene block copolymer (component (A)) used in the thermoplastic polymer composition of the present invention has a melt flow rate (230 ° C, 2.16 kg load, hereinafter simply referred to as “M
FR ”. ) Exceeds 30 to 60 g / 10 min, preferably 32 to 50 g / 10 min, more preferably 35 to 50 g / 10 min.
45 g / 10 min, the MFR of the propylene homopolymer portion in the propylene / ethylene block copolymer exceeds 50 to 90 g / 10 min, preferably 53 to 80 g / 10 min.
Min, more preferably 55 to 70 g / 10 min, and an isotactic pentad fraction (P) of 0.97 or more, preferably 0.98 or more, more preferably 0.98 to 0.99.

[0007] If the MFR of the propylene / ethylene block copolymer is less than the above, fluidity is insufficient and a molding machine having a large clamping force is required when molding a thin-walled molded product. It becomes necessary to raise it, which has an adverse effect on productivity. When the MFR of the propylene / ethylene block copolymer exceeds the above range, the impact resistance characteristics are insufficient. In particular, when the MFR of the propylene homopolymer exceeds the above range, thermal caulking or the like occurs. It is not preferable because a stringing phenomenon occurs at the time of molding. The MFR of the propylene / ethylene block copolymer may be adjusted at the time of polymerization, or may be adjusted with an organic peroxide such as diacyl peroxide or dialkyl peroxide after polymerization. The ethylene content of the propylene / ethylene block copolymer is 2 to 8% by weight,
Preferably, it is 2 to 7% by weight, and the ethylene content of the copolymer part in the block copolymer is 30 to 50% by weight;
In particular, it is 35 to 45% by weight. If the ethylene content in the propylene / ethylene block copolymer is less than the above range, the heat resistance tends to be poor. Those exceeding the above range tend to have insufficient bending rigidity and surface hardness.
On the other hand, if the isotactic pentad fraction (P) of the propylene homopolymer portion is less than the above range, the flexural modulus is insufficient, which is not suitable. Here, the isotactic pentad fraction is an isotactic fraction in pentad units in a polypropylene molecular chain measured using ¹³ C-NMR.

A high stereoregularity catalyst is used for the production of the propylene / ethylene block copolymer. Examples of the production of the above catalyst include a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound and further treating the same with various electron donors and electron acceptors, an organoaluminum compound and an aromatic carboxylic acid. A method of combining with an acid ester (JP-A-56-100806, JP-A-5-100806)
JP-A-6-120712, JP-A-58-104907), and a method of using a supported catalyst in which titanium tetrachloride and various electron donors are brought into contact with a magnesium halide (JP-A-57-63310, 63-439
No. 15, JP-A-63-83116), etc.
Known methods can be exemplified.

[0009] The propylene / ethylene block copolymer is 61 to 87 parts by weight, preferably 70 to 80 parts by weight, when the total of this component and the components (B) and (C) described below is 100 parts by weight. It is. If the blending amount of the propylene / ethylene block copolymer is less than the above range, the flexural modulus is poor, and if it exceeds the above range, the impact resistance is poor.

(B) Ethylene / α-olefin copolymer rubber (component (B)) Ethylene / α-olefin copolymer rubber used in the thermoplastic polymer composition of the present invention
As the α-olefin copolymer rubber, a rubber having a melting temperature of 60 to 100 ° C., preferably 65 to 90 ° C., more preferably 70 to 80 ° C. as measured by a differential scanning calorimeter is suitable. When the melting temperature is lower than the above range, the crystallinity is low and the surface hardness is insufficient, and when the melting temperature is higher than the above range, the impact resistance is insufficient, so that it is inappropriate. Further, the density is less than 0.90 g / cm ³ , preferably 0.87 to 0.1 g / cm ³ .
89 g / cm ³ is used in terms of impact resistance and surface hardness.

The ethylene / α-olefin copolymer rubber is produced by applying a production process such as a gas phase fluidized bed method, a solution method, and a slurry method in the presence of an ionic polymerization catalyst such as a Ziegler catalyst or a Phillips catalyst. It can be obtained by copolymerizing ethylene and an α-olefin, as long as the melting temperature is within the above range regardless of the content of the α-olefin. This α-olefin content is 15
~ 25 wt%, preferably 17-23 wt%,
It can be used in terms of impact resistance and surface hardness.
The α-olefin to be copolymerized with ethylene is a terminal olefin compound having 4 to 8 carbon atoms, such as 1-butene, 3-methyl-1-butene, 1-pentene, 1-hexene, 1-heptene, -Octene and the like. Among them, a copolymer with 1-butene is particularly preferable in that it has excellent balance of impact strength, tensile elongation, and surface hardness. These copolymerized α-olefins need not be one kind, and may be multi-component copolymers using two or more kinds. The MFR of these rubbers is 3 to 10 g / 10
Min, preferably 5 to 8 g / 10 min, more preferably 5 to 10 g / 10 min.
It is in the range of 7 g / 10 minutes. If the MFR of the rubber is too low, physical properties such as embrittlement temperature are poor, and if the MFR is too high, the effect of improving impact resistance is poor.

The ethylene / α-olefin copolymer rubber has a total of 10% of this component, component (A) and component (C).
When 0 parts by weight, 5 to 15 parts by weight, preferably 6 to
13 parts by weight. If the amount of the ethylene / α-olefin copolymer rubber is too small, the impact resistance is poor, and if it is too large, the flexural modulus is poor.

(C) Talc (component (C)) In the thermoplastic polymer composition of the present invention, talc to be blended with the above polymer component is produced by dry pulverization and then dry classification, and has an average particle size. 5 μm or less, preferably 0.5 μm
In ～3Myuemu, and a specific surface area of 3.5 m ² / g or more, preferably 3.5~6m ² / g. If they are out of the above range, the impact resistance is inferior. The average particle size is a particle size value when the cumulative amount is 50% by weight, which is read from a particle size cumulative distribution curve measured using a liquid sedimentation type light drop method (for example, CP type manufactured by Shimadzu Corporation). The specific surface area is measured by an air permeation method (for example, SS manufactured by Shimadzu Corporation)
-100 type constant pressure ventilation type specific surface area measuring device). Talc is an organic titanate-based coupling agent, a silane-based coupling agent, a fatty acid, a fatty acid metal salt, for the purpose of improving adhesiveness or dispersibility with a polymer.
Those treated with a fatty acid ester or the like may be used.

The amount of talc is preferably 8 to 14 parts by weight, based on 100 parts by weight of the total of this component, component (A), component (B) and component (C). Is 9 to 13 parts by weight. If the amount of talc is less than the above range, the flexural modulus is insufficient, and if it exceeds the above range, the specific gravity increases, which is not preferable. Further, the sum of the component (B) and the component (C) needs to be 13 to 25 parts by weight. If the sum is too small or too large, physical properties such as flexural modulus, impact strength, and low-temperature embrittlement temperature cannot be balanced, which is not preferable.

(D) Additional components (optional components) In addition to the above-mentioned essential components, other additional components are added to the thermoplastic polymer composition of the present invention within a range that does not significantly impair the effects of the present invention. Can be. Other additional ingredients include:
An impact-resistant elastomer other than the component (B), for example, an elastomer such as an ethylene / propylene copolymer rubber can be used within a range not to impair the purpose of the present invention. In addition, additives and fillers that are usually blended in the thermoplastic polymer composition can be blended. Specifically, the additives include processability stabilizers, antioxidants, ultraviolet absorbers, light stabilizers, various dispersants including metal soaps, antistatic agents, lubricants, nucleating agents, pigments, and the like. Examples of the filler include whiskers such as fibrous potassium titanate and calcium carbonate, and carbon fibers and glass fibers. The thermoplastic polymer composition of the present invention is preferably a composition not containing a polymer having a polar group, but if it is less than 5% by weight, especially less than 3% by weight, maleic anhydride and methacrylic acid are used. Even if it contains a polymer having a polar group, such as a propylene-based copolymer obtained by copolymerizing monomers such as acid and trimethoxyvinylsilane, and an ethylene-based copolymer obtained by copolymerizing vinyl acetate, etc. It does not impair the effects of the invention.

(2) Production of a thermoplastic polymer composition The thermoplastic polymer composition of the present invention is prepared by mixing the above-mentioned components with a conventional extruder, Banbury mixer, roll, Brabender plastograph, kneader blender or the like. It is manufactured by melting and kneading in a conventional manner, but it is preferable to manufacture using an extruder, particularly a twin-screw extruder. The method of molding the thermoplastic polymer composition of the present invention is not particularly limited, but the injection molding method is most suitable in view of the effect of the invention to be achieved.

[II] Physical Properties of Thermoplastic Polymer Composition The thermoplastic polymer composition of the present invention obtained by the above-mentioned production method has, among others, the following physical properties, and has good workability during injection molding. It has excellent flexural modulus, impact resistance, surface hardness, and heat resistance, and is suitable for injection molded articles such as interior parts for automobiles. The physical properties of the thermoplastic polymer composition of the present invention include (a) a melt flow rate (230 ° C.,
2.16 kg load) is 23 g / 10 min or more, preferably 25 to 35 g / 10 min, and (b) the flexural modulus at 23 ° C. is 20,000 kg / cm ² or more, preferably 22.0 kg / cm ² or more.
00 to 30,000 kg / cm ² , particularly preferably 2
3,000-28,000 kg / cm ² , (c) Izod impact value is 5 kg · cm / cm or more, preferably 6 kg
・ Cm / cm or more, (d) Rockwell hardness is 85 or more,
Preferably 88 to 95, (e) a low-temperature embrittlement temperature of 15 ° C or lower, preferably 0 to 13 ° C,

[III] Applications The thermoplastic polymer composition of the present invention can be used as various materials because of its excellent performance as described above. Thus, the effects of the present invention can be greatly exhibited.

[0019]

The present invention will be described more specifically with reference to the following experimental examples. [I] Measurement method (1) MFR: 2.1 according to ASTM-D1238.
It was measured at 230 ° C. using a 6 kg load. (2) Isotactic pentad fraction (P): ¹³ C-
Macromolecules, 8, 68 using NMR
7 (1975). (3) Melting temperature: 10 mg of a sample was charged into a differential scanning calorimeter (for example, Model 910 DSC manufactured by DuPont), and 180
The sample is heated to a temperature of 100C to melt the sample, and then cooled to a temperature of -100C at a constant rate of 10C per minute. Thereafter, the temperature was raised at a constant rate of 20 ° C. for one minute, and the melting temperature was read from the peak position of the obtained thermogram.

(4) Flexural modulus: Measured at 23 ° C. at a bending speed of 2 mm / min according to ASTM-D790. (5) Impact resistance: 23 in accordance with ASTM-D785.
It evaluated by the Izod impact strength value of ° C. (6) Surface hardness: 23 ° C according to ASTM-D785
Was evaluated on the R scale for Rockwell hardness. (7) Embrittlement temperature: length 3 according to ASTM-D785
8 ± 1.5 mm, width 6.3 mm ± 0.4 mm, thickness 1.
Using a test piece punched out to 9 mm ± 0.2 mm, a linear velocity of 1.8 to 2.1 m / sec was hit to measure. (8) Stringing characteristics: root thickness 11 at the end of the load cell
mmφ: A conical sprue test piece having a tip with a thickness of 4 mmφ is fixed and placed on a hot stage at 170 ° C. for 0.5 min.
After being melt-compressed with a load of 5 kg, it was peeled off at a speed of 500 mm / sec and judged by the manner of pulling the yarn. When the thread was remarkably drawn, it was evaluated as x, and when it was not drawn, it was evaluated as ○.

[II] Experimental Examples Examples 1 to 8 and Comparative Examples 1 to 10 The materials shown in Tables 1 to 3 were blended in the compositions shown in Tables 4 and 5, and tetrakis [methylene-3- (3 ') , 5'-
0.1 part by weight of di-t-butyl-4'hydroxyphenyl) propionate] methane and mixed by a super mixer manufactured by Kawada Seisakusho for 5 minutes, followed by an FCM twin-screw kneader manufactured by Kobe Steel, Ltd. Kneading at a temperature setting of 210 ° C
The mixture was granulated to obtain a thermoplastic polymer composition. Thereafter, various test pieces were prepared at a molding temperature of 210 ° C. using an injection molding machine having a mold clamping force of 100 tons, and the performance was evaluated according to the above-described measurement method.
Tables 6 and 7 show the evaluation results.

[0022]

[Table 1]

[0023]

[Table 2]

[0024]

[Table 3]

[0025]

[Table 4]

[0026]

[Table 5]

[0027]

[Table 6]

[0028]

[Table 7]

[0029]

According to the present invention, a specific ethylene / α-olefin copolymer rubber and talc are blended in a specific ratio with a propylene / ethylene block copolymer having a propylene homopolymer portion having high fluidity and extremely high crystallinity. The thermoplastic polymer composition of the present invention obtained by doing, has good workability during injection molding, excellent appearance, furthermore, flexural modulus,
It is a composition having excellent heat resistance and surface hardness and suitable for injection molded articles such as interior parts for automobiles, and is an industrially extremely useful material.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takeshi Nishio Jun. 1, Toyota-cho, Toyota City, Aichi Prefecture Inside Toyota Motor Co., Ltd. (72) Inventor Yukihito Zaka 1, Toho-cho, Yokkaichi City, Mie Prefecture Mitsubishi Chemical Corporation Inside the Yokkaichi Research Institute (72) Inventor Ikuo Tsutsumi 1 Tohocho, Yokkaichi-shi, Mie Prefecture Mitsubishi Chemical Corporation Inside the Yokkaichi Research Institute (72) Hiroki Sato 1 Tohocho, Yokkaichi-shi, Mie Mitsubishi Chemical Corporation (56) References JP-A-7-18151 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 53/00

Claims (1)

(57) [Claims] 1. Component (A): a melt flow rate (230 ° C., 2.16 kg load) of more than 30 to 60 g / 10 min, and a melt flow rate of a propylene homopolymer portion (230 ° C., 2.16 kg); A propylene / ethylene block copolymer having an isotactic pentad fraction of 0.97 or more with an ethylene content of 2 to 8% by weight and a block copolymer weight of more than 50 to 90 g / 10 min. 61-87 parts by weight of a propylene / ethylene block copolymer having an ethylene content of 30-50% by weight of the copolymer in the copolymer (B) Component: Melted to 60-100 ° C as measured by a differential scanning calorimeter. Ethylene-α-olefin having a temperature, a melt flow rate (230 ° C., 2.16 kg load) of 3 to 10 g / 10 min, and an α-olefin having 4 to 8 carbon atoms. A fin copolymer rubber, a density of less than 0.90 g / cm ^3, and alpha-olefin containing amount is 15 to 25 wt%, an ethylene · alpha-olefin copolymer rubber 5-15 parts by weight Component (C): 8 to 14 parts by weight of talc having an average particle size of 5 μm or less and a specific surface area of 3.5 m ² / g or more, and the total weight of components (A), (B) and (C) Is 100 parts by weight, and the sum of the above components (B) and (C) is 13 to 25 parts by weight, and the physical properties of the composition formed therefrom are as follows. Rate (230 ° C., 2.16 kg load) is 23 g / 10 min or more, flexural modulus at 23 ° C. is 20,000 kg / cm ² or more, Izod impact value is 5 kg · cm / cm or more, and Rockwell hardness is 85 As described above, the low-temperature embrittlement temperature is 15 ° C or less. Thermoplastic polymer composition, characterized in that.