JPS58162652A - Polypropylene composition for large-sized molded article - Google Patents

Abstract

PURPOSE:To provide a polypropylene composition having excellent rigidity and heat deformation resistance, high impact strength, and low density, and capable of giving a large-sized molded article having excellent appearance and durability and high rigidity, by using a crystalline ethylene-propylene block copolymer as a main component. CONSTITUTION:The objective composition is composed of (A) a crystalline ethylene-propylene block copolymer having an ethylene content of <=20wt%, a melt flow rate (MFR) of 2-10g/min, the content of the component soluble in p-xylene at normal temperature of 5-15wt%, ethylene content in the above soluble matter of 25-45wt%, and an intrinsic viscosity eta of 3-5dl/g (in decaline at 135 deg.C), (B) an amorphous ethylene-propylene copolymer having a Mooney viscosity ML1+4 (100 deg.C) of 15-100, and (C) talc having an average particle diameter of 1-4.5mu. The amounts of the components (B) and (C) are 3-6wt% and 18-30wt%, respectively, based on 100wt% of the sum of the components (A), (B) and (C).

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polypropylene composition suitable for highly rigid large-sized molded articles, and more specifically, the present invention relates to a polypropylene composition containing a crystalline ethylene-propylene block copolymer as a main component.

In particular, it has excellent rigidity and heat deformation resistance, and high impact strength.
We can provide large molded products that are lightweight and have a good appearance.
Furthermore, the present invention relates to a polypropylene composition for large-sized molded products that has good moldability when molded into large-sized molded products.

Conventionally, ABS, Noryl (modified PP0), ASO, polycarbonate, etc. have been used as materials for plastic industrial parts such as home appliances and automobiles. However, these polymers have problems in impact strength, rigidity, or moldability, and are not fully satisfactory as materials for plastic industrial parts.

On the other hand, inorganic filler-filled polypropylene, which is a mixture of crystalline polypropylene and inorganic filler, has recently been used as a material for plastic industrial parts such as home appliances and automobiles. However, this inorganic filler-filled polypropylene has the drawbacks of low impact strength and high density of molded products formed from it.

For this reason, conventionally known inorganic filler-filled polyglopylenes can be used in applications where impact resistance is not particularly required, but they cannot be used in applications where both rigidity and impact resistance are required. be.

Therefore, in order to improve the impact resistance of conventional inorganic filler-filled polypropylene, we have developed a composition in which inorganic filler-filled polypropylene is blended with a large amount of rubber such as an amorphous ethylene-propylene copolymer, or a fine inorganic filler is used as an inorganic filler. Many compositions have been proposed. but.

Compositions obtained by blending a large amount of rubber improve the impact resistance of the molded product, but the rigidity and heat deformation resistance decrease, and the appearance of the molded product deteriorates because it is difficult to uniformly mix the polypropylene, inorganic filler, and rubber. In addition, the Izot impact strength of the molded product is improved by adding a fine inorganic filler to the composition. When we assembled home appliances, automobiles, etc. and observed whether or not aluminum molded products would break due to practical impact, we found that they often broke and were not suitable for practical use.

This suggests that when one composition has high rigidity, the Izot impact strength of the test piece alone is insufficient as a criterion for determining the impact resistance when one composition is molded into a large molded product. It is something to do.

The inventors have conducted various studies on methods for determining impact strength that correspond well to practical impact resistance when molded into large molded products.

The surface impact strength (a type of falling weight impact strength that indicates the energy required for destruction by a falling weight, sometimes abbreviated as 9.Hs) determined by the measurement method described below is 350 kg.
A or more, Izotsu impact strength at 23℃ is 10kg
- It has been found that in cases of ~~ or above, there is almost no destruction caused by practical impact.

Based on the above-mentioned opinion, the inventors determined that the rigidity of a molded product is determined by the flexural modulus, the heat deformation resistance is determined by the heat deformation temperature, and the impact resistance is determined by the Izot impact strength and the above-mentioned surface impact strength. Pay attention.

This is the result of intensive research aimed at improving the above-mentioned drawbacks of conventionally known inorganic filler-containing polypropylene compositions and obtaining a polypropylene composition that has no practical problems as a material for large molded products used in home appliances, automobiles, etc. The above object is achieved by blending talc with a specific particle size and an amorphous ethylene-propylene copolymer with a specific Mooney viscosity in a specific ratio into a specific crystalline ethylene-propylene block copolymer according to the present invention. He discovered this and completed this invention.

That is, this invention provides ethylene content [20% by weight or less, melt flow rate (MFR)] 2 to 102/10.
minutes, para-xylene soluble content at room temperature 5-15% by weight, ethylene-containing lid 25-45% by weight of the para-xylene soluble content at room temperature, intrinsic viscosity [η] (decalin, 135°C) 3-5
eL1/f crystalline ethylene-propylene block copolymer (a), Mooney viscosity ML1+4 (100'
C) Each of the above components (a) consists of an amorphous ethylene-propylene copolymer (b) having a particle size of 15 to +100 μm and talc (c) having an average particle size of 1 to 4.5 microns.

(b) is 3 in total 100 weight of (b) and (C)
The present invention relates to a polypropylene composition for large-sized molded articles in which (C) is blended in a proportion of ~6% by weight and (C) in a proportion of 18% to 30% by weight.

The composition of this invention has a density of 1.15 l/d or less.

Flexural modulus is 25,000 Kt/d or more, Izot impact strength (notched) at 23°C is 10 to 6 or more, Surface impact strength at -10°C is 350 Kg by the measurement method described below.
-cm or more, the heat distortion temperature is 120℃ or more, and even when molded into a large molded product with a length of 1rrL or more, it is glossy and no flow marks are observed, and when molded into a large molded product, Good moldability.

While retaining the inherent rigidity and heat deformation resistance of inorganic filler-filled polypropylene, the impact resistance, moldability 2 and appearance are greatly improved, and it can be molded into large, lightweight molded products.

The crystalline ethylene-propylene block copolymer (a) used in the polypropylene composition for large molded articles of the present invention has an ethylene content of 20% by weight or less, and has a melt flow rate (VFR) of 2 to 2. 10f/10
The para-xylene soluble content at room temperature (consisting of amorphous ethylene-propylene copolymer and low molecular weight 1 polymer) is 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 room temperature xylene soluble component (decalin).

135℃) is 3-5 eL17? belongs to. In particular, crystalline ethylene-propylene block copolymers having an ethylene content of 3 to 15% by weight are preferably used in the polypropylene composition for large-sized molded products of the present invention.
Melt Flow Ray) (MFR) is 3 to 101i'71
0 minutes, the room temperature para-xylene soluble content is 7 to 12% by weight, and the room temperature para-xylene soluble content has an ethylene content of 30 to 40% by weight. Intrinsic viscosity of soluble component [η] (decalin, 135℃)
is 3 to 5 dl/l. If the crystalline ethylene-propylene block copolymer used is outside the range specified above, it will not be possible to obtain the desired large molded product with excellent rigidity and heat deformation resistance, high impact strength, light weight, and good appearance. It is not possible to obtain polypropylene compositions that provide

Although it is not clear why the polypropylene composition of this invention exhibits good physical properties when molded into a large molded article, the specific crystalline ethylene-propylene block copolymer used in this invention and the amorphous ethylene-propylene block copolymer It is considered that some kind of strong interaction occurs between the polymer and talc.

The crystalline ethylene-globylene block copolymer (
a) is a crystalline ethylene-propylene block copolymer (
ζ = suitable (2 is 6
It is blended in an amount of 5 to 79% by weight, particularly preferably 70 to 77% by weight. When the above blending amount is less than 65% by weight or more than 79% by weight, the molded article tends to have a lower rigidity and heat deformation resistance, or a lower impact resistance of the molded article. 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-propylsine copolymer (b) Fi, used in the polypropylene composition of this invention.

Mooney viscosity ML1+4 (100℃) is 15~1°
00, and preferably has an ethylene content of 50 to 90% by weight. Mooney viscosity ML1+4 (
100° C.) is less than 15, the rigidity and impact resistance of the molded article decreases, and when it exceeds 10°, it becomes difficult to uniformly disperse the amorphous ethylene-propylene copolymer by kneading.

The anatomical ethylene-propylene copolymer (b) has a total of 10 of the components (a), (b) and (c).
It is blended in an amount of 3 to 6 t% in 0% by weight. If the above blending amount is less than 3% by weight, the isot impact strength and surface + 14 impact strength (H8I) of the molded product exceeds /J% × 9.6% by weight, the bending elasticity of the molded product As the ratio decreases, the heat deformation resistance decreases. Two or more non-podal ethylene-propylene copolymers may be used as long as the total amount is within the above range.

The talc used in the boria'lopyrene compositions of this invention has an average particle size of 1 to 4.5 microns.

Preferably it is 1.5 to 3.5 microns. The average particle size here is the particle size at the 50th point on the particle size distribution integral curve. If the above average particle size is less than 1 μm, the surface impact strength of the molded product will be low, and if the above average particle size exceeds 4.5 μm, the flexural modulus and iso impact strength of the molded product will be low. The impact strength becomes smaller.

The talc (C) contains the components (a), (b) and (
It is blended in an amount of 18 to 30% by weight, preferably 20 to 30% by weight in the total 100% by weight of C). The above blending amount is 18
If the amount is less than 30% by weight, the flexural modulus of the molded product will be small and the heat deformation temperature will be low, and if the above content exceeds 30% by weight, the Izo impact strength and surface impact strength of the molded product will decrease. As the number decreases, the density increases and the moldability of the composition decreases.

Talc may be used untreated, but for the purpose of improving dispersibility, various organic titanate coupling agents, silane thread coupling agents, saturated or unsaturated fatty acids, carboxylic acids having vinyl unsaturated bonds, fatty acid metal salts,
It is also possible to use particles whose surface rfJ has been treated with fatty acid ester, fatty acid amide, or the like. Two or more talc units may be used as long as the total accumulation is within the above range.

The polypropylene compound/parabolite of the present invention can be produced using a kneading machine such as a Banbury Mixer-0 twin screw extruder, FCM, Nigoo, two-stage twin screw extruder, or KCK extruder. Usually, the composition is kneaded in the above mixer to form a pellet-like composition and then subjected to processing.

The pellet-like composition was prepared by kneading talc in advance as a high-concentration masterbatch (the above-mentioned crystalline ethylene-propylene block copolymer was used as the base polymer) and an additional crystalline ethylene-propylene block copolymer. It may also be produced by diluting it with an anatomical ethylene-propylene copolymer.

Alternatively, it may be manufactured by directly kneading each component.

Other resins such as high-density polyethylene, rubber, or other fillers such as calcium carbonate, barium sulfate, etc., may be used to the extent that the effects obtained by the polypropylene compositions of this invention are not impaired.

Mica, clay, titanium oxide, diatomaceous material, bolast 4
A suitable amount of the following can be blended into the polypropylene composition of the present invention.

In addition, in order to further improve 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. By, ri,
2.6-di-tert-butylphenol 1216-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-)riazine, n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenyl) globione), 2,6-di-tert-butyl-4-methylphenol (BHT), tris-(2-methyl-4-hydroxy-5-tert) Butylphenylcobutane, tetrakis-[methylene 3- (3'
, 5'-di-tert-butyl-4'-hydroxyphenyl)globionate]methane t L3*5- ) ') /
Antioxidants such as 2.4.6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and dilaurylthiodipropionate; 2-hydroxy-4
-n-octoxybenzophenone, 2-hydroxy-4
-octadecyloxybenzophenone, 4-dobucyloxy-2-hydroxybenzophenone, nickel-bis-(
Orthoethyl-3,5-ditert-butyl-4-hydroxybenzyl)phosphonate, 2-hydroxy-4-n-octoxybenzophenone, 2-(2'-hydroxy-3
'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'
, 5'-cytertiary 7-f-ruphenyl)-5-chlorobenzotriazole, bis-(2,6-dimethyl-4-piperidyl) sebacate; antimony trioxide, tricresyl phosphate, halogenated Flame retardants such as alkyl triazine, decapromoxy 7-enyl ether, and chlorinated polyethylene; Pigments such as carbon blank and titanium oxide; Paintability improvers such as magnesium benzoate; Plasticizers such as process oil; Fatty acid metal salts, etc. A lubricant; an antistatic agent such as polyoxyethylene alkyl ether can also be blended.

The polypropylene compositions of the invention are molded by methods known per se 9, for example by injection molding.

It is possible to obtain a large, highly rigid molded product with excellent rigidity and heat deformation resistance, high impact strength, light weight, and good appearance and durability.

Examples and comparative examples are shown below. In the following description, "parts J" and "r%J" each refer to "parts by weight".

Melt flow rate (MFR) is defined as "wt%" according to ASTM D1238 (230°C, 2.16~).
Density is ASTM D1505 1 Flexural modulus is AST
MD790, Izotsu impact strength is ASTM
D256, heat distortion temperature according to ASTM D648, and Mooney viscosity ML1+4 (100℃) according to JIS K6.
300. Also, single-sided impact strength (H8I
) is the relationship between the stress and strain of the energy required to break when a steel falling weight with a tip diameter of 2.5 m/sec collides with a 1.6°C thick molded product at a speed of 2.5 m/sec. It is expressed by the area of the part surrounded by the stress-strain curve shown and each axis. The normal temperature (approximately 20°C) para-xylene soluble portion of crystalline polypropylene is obtained by adding Polymer 52 to para-xylene 500 along with about 100% of antioxidant and completely dissolving it under heating, and then - day and night. After being left at room temperature, the precipitated insoluble matter was removed by centrifugation, the soluble matter solution was poured into acetone, and the precipitated insoluble matter was dried under reduced pressure. The ethylene content of the soluble portion was determined using the Gardner method, and the intrinsic viscosity [η] was determined at 135° C. using decalin as a solvent.

Example: 7% ethylene-containing lid, Melt Flow Ray) (MF R)
31710 minutes, room temperature para-xylene soluble content 9.3 yen,
Ethylene content of para-xylene soluble at room temperature: 33.3
71 parts of a crystalline ethylene-propylene block copolymer (hereinafter referred to as EP copolymer A) with an intrinsic viscosity of 4.1a/2 and a Mooney viscosity of ML1+4 (10
0℃)65. Intrinsic viscosity [η]2.3 tfJJ, /9(
Decalin, 135℃, same below), ethylene content approx. 7
0% amorphous ethylene-propylene li combination (hereinafter E
25 parts of talc with an average particle size of 2.8μ, and tetrakis-[methylene 3- (3', 5
After mixing 0.1 part of '-di-tert-butyl-4'-hydroxyphenyl]propionate]methane and 1 part of BHTo in a tumbler for 15 minutes.

The mixture was kneaded and extruded at 220°C using a twin-screw presser to form pellets.

The melt flow rate (MFR) of the obtained pellet-shaped polypropylene composition, and the density 1 flexural modulus, Izotz impact strength 1 plane impact strength, and heat distortion temperature of test pieces obtained from this composition by injection molding were determined. It is shown in Table 1. In addition, this composition was molded into a large molded product (box-shaped with a length of 135 mm and a width of 30 cm, and a wall thickness of 3 mm) by injection molding.

Table 1 shows the results of evaluating the moldability and observing the appearance.

Comparative Example 1 As a crystalline ethylene-propylene block copolymer,
Ethylene content 3%, ypR3f/10 min.

Room temperature para-xylene soluble content: 4.21 Ethylene content of the room temperature para-xylene soluble content: 35.0%.

[η) 3.8 di/? A sleeve using the crystalline ethylene-propylene block copolymer C (hereinafter referred to as EP copolymer a) was prepared in the same manner as in Example 1. The results are summarized in Table 1.

Examples 2-3. Comparative Examples 2-3 As a crystalline ethylene-propylene Pronk copolymer,
Example 1 was carried out in the same manner as in Example 1, except that the type of polypropylene shown in Table 2 was used instead of EP copolymer A. The results are summarized in Table 3.

Table 2 Examples 4-5. Comparative example 4 As an anatomical ethylene-propylene copolymer.

A pond using the type of rubber shown in No. 4S in place of EPR-A was carried out in the same manner as in Example 2. The results are summarized in Table 5.

Table 4 Implementation+"/116-7. Comparative Examples 5-6 Songs using the types of talc shown in Table 6 as talc were performed in the same manner as in Example 1. The results are summarized in Table 6.

Examples 8-10. Comparative Examples 7 to 10 Comparative Examples 7 to 10 were carried out in the same manner as in Example 1 except that the blending ratio of each component was changed. The results are summarized in Table 7.

Claims (1)

[Claims] Low ethylene content of 20% by weight or less, melt flow rate (
MF'R) 2 to 109710 minutes, 5 to 15% by weight of para-xylene soluble content at room temperature, and 25 to 45% by weight of ethylene content of the para-xylene soluble content at room temperature. Intrinsic viscosity [η] (decalin, 135°C) 3-5q Current crystalline ethylene-propylene block copolymer (a), Mooney viscosity & MLl+4 (100°C) 15-100
an amorphous ethylene-propylene copolymer (b), and talc (c) having an average particle size of 1 to 4.5 microns. Total of each of the above components (a), (b) and (e): 100
(b) is 3-6% heavy snow during heavy dochi, (C) is 18-30%
A polypropylene composition for large molded products, which is blended in proportions by weight.