JPS6328463B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a polypropylene composition suitable for highly rigid molded articles, and more specifically, to a polypropylene composition suitable for highly rigid molded articles.
The present invention relates to a polypropylene composition containing a propylene block copolymer as a main component, which has particularly excellent rigidity and heat deformation resistance, and is capable of producing lightweight molded articles with high impact strength. Conventionally, ABS, Noryl, etc. have been mainly used as materials for plastic industrial parts such as home appliances and automobiles. However, these polymers are expensive, have insufficient impact strength, stiffness or heat deformation resistance, and are not fully satisfactory as materials for plastic industrial parts. On the other hand, crystalline polypropylene is used in large quantities because it is lightweight, inexpensive, and has excellent chemical resistance, but it is inferior in rigidity and heat deformation resistance compared to the above-mentioned polymers. To remedy this drawback, they are generally filled with inorganic fillers. However, this inorganic filler-filled polypropylene has low impact strength and
It has the disadvantage that the density of the molded product molded from this is high. For this reason, conventionally known inorganic filler-filled polypropylene can be used in applications where impact resistance is not particularly required, but it cannot be used in applications where both rigidity and impact resistance are required. . Therefore, the inventors conducted intensive research with the aim of obtaining a polypropylene composition with a density comparable to or even lower than that of ABS and Noryl, and with rigidity, heat deformation resistance, and impact resistance comparable to or higher than that of ABS and Noryl. As a result, the above object is achieved by blending the amorphous ethylene-propylene copolymer and the powdered inorganic filler with the specific crystalline ethylene-propylene block copolymer in the present invention in a specific ratio. He discovered this and completed this invention. That is, this invention has an ethylene content of 20% by weight or less and a melt flow rate (MFR) of 0.05 to 1.5.
g/10 minutes, para-xylene soluble content at room temperature 4.5 to 15% by weight, ethylene content 25 to 45% by weight of the para-xylene soluble content at room temperature, intrinsic viscosity [η] (decalin,
135°C) 3-5 dl/g crystalline ethylene-propylene block copolymer (a), Mooney viscosity ML ₁₊₄
(100°C) 5 to 200% amorphous ethylene-propylene copolymer (b), and a powdered inorganic filler (c) with an average particle size of 0.05 to 3.5 microns, each of the above components (a),
This invention relates to a polypropylene composition in which (b) is blended in a proportion of 3 to 6% by weight and (c) is blended in a proportion of 15 to 22% by weight in a total of 100% by weight of (b) and (c). The polypropylene composition of this invention has a density of
1.05g/cm ³ or less, bending elastic modulus 25000Kg/cm ² or more,
Izot impact strength (notched) at 23℃ is 30
Kg・cm/cm or more, heat distortion temperature is 117℃ or more,
While retaining the inherent rigidity and heat deformation resistance of polypropylene filled with inorganic fillers, the impact resistance is greatly improved, and it is possible to mold into lightweight molded products. The crystalline ethylene-propylene block copolymer (a) used in the polypropylene composition of the present invention has an ethylene content of 20% by weight or less and a melt flow rate (MFR) of 0.05 to 1.5.
g/10 minutes, the content soluble in para-xylene at room temperature (consisting of an amorphous ethylene-propylene copolymer and a low molecular weight polymer) is 4.5 to 15% by weight, and the para-xylene soluble at room temperature The ethylene content is 25 to 45% by weight, and the intrinsic viscosity [η] of the para-xylene soluble component at room temperature (Decalin, 135℃)
is 3 to 5 dl/g. In particular, the crystalline ethylene-propylene block copolymer preferably used in the polypropylene composition of the present invention is
It has an ethylene content of 3 to 15% by weight, a melt flow rate (MFR) of 0.1 to 1.5g/10 minutes, a content soluble in para-xylene at room temperature of 7 to 12% by weight, and The ethylene content of the room temperature para-xylene soluble portion is 30 to 40% by weight, and the room temperature para-xylene
Intrinsic viscosity of xylene soluble component [η] (decalin, 135
°C) is 3 to 5 dl/g. If the crystalline ethylene-propylene block copolymer used is outside the range specified above, it will have excellent rigidity and heat deformation resistance, high impact strength, and
It is not possible to obtain polypropylene compositions that provide lightweight molded articles. Although the reason why the polypropylene composition of this invention exhibits good physical properties when molded into a molded article is not clear, the specific crystalline ethylene-propylene block copolymer used in this invention and the amorphous ethylene-propylene It is considered that some kind of strong interaction occurs between the copolymer and the powdered inorganic filler. The crystalline ethylene-propylene block copolymer (a) is composed of the crystalline ethylene-propylene block copolymer (a), the amorphous ethylene-propylene copolymer (b) and the powdered inorganic filler (c). It is preferably blended in an amount of 75 to 82% by weight in a total of 100% by weight. When the above-mentioned amount is less than 75% by weight or exceeds 82% by weight, the molded article tends to have lower rigidity and heat deformation resistance, and has a lower impact resistance. Two or more types of crystalline ethylene-propylene block copolymers may be used as long as the total amount is within the above range. Amorphous ethylene-propylene copolymer (b) used in the polypropylene composition of this invention
has a Mooney viscosity ML ₁₊₄ (at 100° C.) of 5 to 200 (preferably 10 to 100) and preferably has an ethylene content of 50 to 85% by weight. If the above Mooney viscosity ML ₁₊₄ (100℃) is less than 5, the rigidity and impact resistance of the molded product will decrease, and if it exceeds 200, the amorphous ethylene-propylene copolymer will become uniform during kneading. Difficult to disperse. The amorphous ethylene-propylene copolymer (b)
is 100% by weight of the above components (a), (b) and (c)
It is blended in an amount of 3 to 6% by weight. The above blending amount is 3
If it is less than 6% by weight, the impact strength of the molded article will be reduced, and if it exceeds 6% by weight, the rigidity and heat deformation resistance of the molded article will be reduced. Two or more types of amorphous ethylene-propylene copolymers may be used as long as the total amount is within the above range. Powdered inorganic fillers used in the polypropylene composition of the present invention include calcium carbonate, barium sulfate, talc, silica, titanium oxide, mica, diatomaceous earth, clay, and the like. The above powdered inorganic filler has an average particle size of 0.05~
A 3.5 micron one is used. The average particle size here refers to the particle size at the 50% point on the particle size distribution integral curve. Among the powdered inorganic fillers mentioned above, talc with an average particle size of 1 to 3.5 microns and talc with an average particle size of 1 to 3.5 microns are
Calcium carbonate between 0.05 and 0.2 microns is preferably used. If the above average particle size is less than 0.05 μm, it will be difficult to uniformly disperse the powdered inorganic filler through kneading, and if the above average particle size exceeds 3.5 μm, the rigidity and impact strength of the molded product will decrease. do. The powdered inorganic filler (c) is blended in an amount of 15 to 22% by weight, preferably 15 to 20% by weight, in a total of 100% by weight of the components (a), (b) and (c). The above compounding amount is
If it is less than 15% by weight, the rigidity of the molded product will decrease and the heat distortion temperature will decrease, making it difficult to maintain the above blending amount.
When the amount exceeds 22% by weight, the impact strength of the molded article decreases, the density increases, and the moldability of the composition decreases. Powdered inorganic fillers may be used untreated, but in order to improve dispersibility during kneading, various organic titanate coupling agents, silane coupling agents, fatty acids, and carboxylic acids having vinyl unsaturated bonds may be used. , fatty acid metal salts,
Particle surfaces coated with fatty acid ester, fatty acid amide, etc. may also be used. Two or more types of powdered inorganic fillers may be used as long as the total amount is within the above range. The polypropylene composition of the present invention can be produced using a kneader such as a Banbury mixer, twin screw extruder, or FCM. Usually, the composition is kneaded in the above-mentioned kneading machine to form a pellet-like composition, which is then subjected to processing. The pellet-like composition is prepared by kneading a powdered inorganic filler in the form of a high-concentration masterbatch (the above-mentioned crystalline ethylene-propylene block copolymer or amorphous ethylene-propylene copolymer is used as the base polymer) and additional materials. It may be produced by diluting the crystalline ethylene-propylene block copolymer and the amorphous ethylene-propylene copolymer, or it may be produced by directly kneading each component. Appropriate amounts of other resins, other rubbers, or other inorganic fillers can be blended into the polypropylene composition of the present invention to the extent that the effects obtained by the polypropylene composition of the present invention are not impaired. In addition, in order to further improve the various performances of molded articles molded from the polypropylene composition of the present invention, there is also a method of adding the polypropylene composition at the time of mixing, after mixing each component, or to the polymer component in advance. 2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol, 2,6-di-tert-butyl -α-dimethylamino-para-cresol, 6-(4-hydroxy-3,5-di-tert-butylanilino)-2,
4-bisoctyl-thio-1,3,5-triazine, n-octadecyl-3-(4'-hydroxy-
3',5'-di-tert-butylphenyl) propionate, 2,6-di-tert-butyl-4-methylphenol (BHT), tris-(2-methyl-4-hydroxy-5-tert-butylphenyl) butane, tetrakis -[Methylene 3-(3',5'-di-tert-butyl-
4'-hydroxyphenyl)propionate] methane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, dilaurylthiodipropionate, etc. Antioxidant; 2-hydroxy-4-n-
Octoxybenzophenone, 2-hydroxy-4
-octadecyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, nickel-bis-(orthoethyl-3,5-di-tert-butyl-4-hydroxybenzyl)phosphonate, 2
-hydroxy-4-n-octoxybenzophenone, 2-(2'-hydroxy-3'-tert-butyl-5'-
methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butyl-phenyl)-5-chlorobenzotriazole,
UV absorbers such as bis-(2,6-dimethyl-4-piperidyl) sebacate; flame retardants such as antimony trioxide, tricresyl phosphate, halogenated alkyl triazine, decabrom diphenyl ether, and chlorinated polyethylene; carbon Pigments such as black and titanium oxide; paintability improvers such as magnesium benzoate; plasticizers such as process oil; lubricants such as fatty acid metal salts; and antistatic agents such as polyoxyethylene alkyl ether. You can also do that. The polypropylene composition of the present invention is molded by a method known per se, such as injection molding, extrusion molding, compression molding, vacuum molding, or pressure molding, and has excellent rigidity and heat deformation resistance, high impact strength, light weight, and durability. A highly rigid molded product with good properties can be obtained. Examples and comparative examples are shown below. In the following description, "parts" and "%" mean "parts by weight" and "% by weight", respectively, and melt flow rate (MFR)
According to ASTM D1238 (230℃, 2.16Kg), the density is
ASTM D1505, flexural modulus is ASTM D790
, Izot impact strength to ASTM D256, heat distortion temperature to ASTM D648, Mooney viscosity ML ₁₊₄
(100°C) was measured according to JISK6300. The para-xylene soluble portion of crystalline polypropylene at room temperature (approximately 20℃) is obtained by mixing 5 g of polymer with 500 ml of para-xylene.
After adding about 1% of antioxidant to the solution and completely dissolving it under heating, leave it at room temperature for a day and night, remove the precipitated insoluble matter by centrifugation, and pour the soluble matter solution into acetone to precipitate. The insoluble matter was dried under reduced pressure. The ethylene content of the soluble portion was determined by the Gardner method, and the intrinsic viscosity [η] was determined at 135°C using decalin as a solvent. Example 1 Ethylene content 5.5%, melt flow rate (MFR) 1.0 g/10 min, normal temperature para-xylene soluble content 8.2%, normal temperature para-xylene soluble content, ethylene content 33.0%, intrinsic viscosity [η ] 75 parts of 3.7 dl/g crystalline ethylene-propylene block copolymer (hereinafter referred to as EP copolymer A), Mooney viscosity ML ₁₊₄ (100°C) 65, intrinsic viscosity [η] 2.25 dl/g
(Decalin, 135℃, same below), ethylene content
5 parts of 74% amorphous ethylene-propylene copolymer (hereinafter referred to as EPR-A), 20 parts of talc with an average particle size of 2.5μ, and tetrakis-[methylene 3-(3',
5′-Ditert-butyl-4′-hydroxyphenyl)propionate] 0.2 parts of methane and 0.1 parts of BHT were mixed for 1 minute in a Henschel mixer, then the maximum setting temperature was 220°C using a Kobe Steel 2FCM. The mixture was kneaded and extruded into pellets. Table 1 shows the melt flow rate (MFR) of the pellet-like polypropylene composition obtained, and the density, flexural modulus, Izot impact strength, and heat distortion temperature of test pieces obtained from this composition by injection molding. Shown below. For reference, the physical properties of commercially available Noryl and ABS, which are used as materials for plastic industrial parts, are summarized in Table 1. Example 2 As a crystalline ethylene-propylene block copolymer, ethylene content 6%, MFR 0.3g/10
Crystalline ethylene-propylene block copolymer (EP copolymer) with a para-xylene soluble content at room temperature of 8.2%, a para-xylene soluble content at room temperature, an ethylene content of 32.0%, and an intrinsic viscosity [η] of 3.9 dl/g. B
Example 1 was carried out in the same manner as in Example 1, except that the following was used. The results are summarized in Table 1.

[Table] Example 3 The same procedure as in Example 1 was carried out except that 77 parts of EP copolymer A, 3 parts of EPR-A, and 20 parts of talc were used. The results are summarized in Table 2. Examples 4-5 As an amorphous ethylene-propylene copolymer,
Mooney viscosity ML ₁₊₄ (100℃) instead of EPR-A
40, amorphous ethylene-propylene copolymer with an intrinsic viscosity of 1.89 dl/g and an ethylene content of 76% (hereinafter
EPR-B) or Mooney viscosity ML ₁₊₄ (100℃) 10, intrinsic viscosity 1.40 dl/g,
The same procedure as in Example 3 was carried out except that an amorphous ethylene-propylene copolymer (hereinafter referred to as EPR-C) having an ethylene content of 76% was used. The results are summarized in Table 2. Example 6, Comparative Example 2 The same procedure as Example 3 was carried out except that the proportions of each component were changed to those shown in Table 2. Summary of the results in the second
Shown in the table. Comparative Example 3 As a crystalline ethylene-propylene block copolymer, ethylene content 2.5%, MFR 1.0g/10
Crystalline ethylene-propylene block copolymer (hereinafter referred to as EP copolymer) with a para-xylene soluble content at room temperature of 4.0%, a para-xylene soluble content at room temperature, an ethylene content of 36.0%, and an intrinsic viscosity [η] of 3.8 dl/g. a
Example 3 was carried out in the same manner as in Example 3, except that the following was used. The results are summarized in Table 2.

【table】

Claims (1)

[Claims] 1. Ethylene content of 20% by weight or less, melt flow rate (MFR) of 0.05 to 1.5 g/10 minutes, room temperature para-
Xylene soluble content: 4.5 to 15% by weight, ethylene content of the normal temperature para-xylene soluble content: 25 to 45% by weight,
Intrinsic viscosity [η] (decalin, 135℃) 3-5 dl/g
crystalline ethylene-propylene block copolymer
(a), an amorphous ethylene-propylene copolymer (b) with a Mooney viscosity of ML ₁₊₄ (100°C) 5 to 200, and a powdered inorganic filler (c) with an average particle size of 0.05 to 3.5 microns, A polypropylene composition in which (b) is blended in a proportion of 3 to 5% by weight and (c) is blended in a proportion of 15 to 22% by weight in a total of 100% by weight of each of the above-mentioned components (a), (b) and (c). thing.