JP3251607B2 - Impact resistant polypropylene molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molded article of impact-resistant polypropylene resin. More specifically, the present invention relates to a molded article substantially composed of a copolymer of polypropylene and ethylene and propylene having a syndiotactic structure and having no problem such as the emergence of the copolymer of ethylene and propylene on the surface of the molded article.

[0002]

2. Description of the Related Art Syndiotactic polypropylene has been known for a long time, but the conventional method of polymerizing at low temperature with a catalyst comprising a vanadium compound, ether and organoaluminum has poor syndiotacticity and syndiotactic polypropylene. It was hard to say that it exhibited the characteristics of polypropylene, and even more so, a copolymer of ethylene and propylene was hardly a crystalline polypropylene. On the other hand, according to JAEWEN et al., The syndiotactic pentad fraction was reduced to 0 by a catalyst comprising a transition metal catalyst component having an asymmetric ligand and an aluminoxane.
It has been discovered for the first time that a polypropylene with good tacticity of more than 7 can be obtained (J. Am. Chem. So
c., 1988, 110, 6255-6256).

[0003]

The above-mentioned method by JAEWEN et al. Has good activity per transition metal, high tacticity of the obtained polymer and relatively good physical properties of the polymer. There is a problem that the low-temperature impact resistance is poor. On the other hand, it is conceivable to mix a copolymer of ethylene and propylene, which is effective in improving the physical properties.
When formed into a molded product, there is a problem that the copolymer of ethylene and propylene emerges on the surface, unlike the one based on isotactic polypropylene.

[0004]

Means for Solving the Problems The present inventors have solved the above-mentioned problems and have enthusiastically searched for a molded article of polypropylene which is excellent in impact resistance and which has no problem on the surface of the molded article and which has an excellent balance of physical properties. Completed the invention.

That is, the present invention provides a syndiotactic penta
Propylene homopolymer with a pad fraction of 0.6 or more
A copolymer of pyrene and another olefin, wherein 1,2,2
By ¹³ C-NMR measured with 4-trichlorobenzene solution
The peak intensity observed at 20.2 ppm is
1 or more of the peak intensity attributed to the methyl group
The intrinsic viscosity of 0.1 as measured with a tetralin solution at 35 ° C.
20 is a syndiotactic polypropylene 3
0 to 98 parts by weight and ethylene (up to half the amount of carbon
α-olefin may be substituted)
It is an impact-resistant polypropylene molded product obtained by extruding a composition comprising 2 to 70 parts by weight of a copolymer of ethylene and propylene at t% .

The molded product of the present invention will be described in detail below by describing a method for producing the molded product.

As the catalyst suitable for synthesizing the polypropylene having a substantially syndiotactic structure which is one component of the composition of the present invention, the compounds described in the above-mentioned documents can be exemplified. When a propylene homopolymer was produced, the syndiotactic pentad fraction of the resulting polymer (A. Zambelli et al., Macromolecules vol66)
87 (1973), vol. 8 925 (1975)) Any catalyst system that provides a polymer having a relatively high tacticity of about 0.7 or more can be used.For example, a transition metal compound having an asymmetric ligand can be used. A catalyst system composed of organoaluminum is effective.

Examples of suitable catalyst systems include isopropyl (cyclopentadienyl-1-fluorenyl) hafnium dichloride or isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride described in the above literature. Examples of the organoaluminum include aluminoxane or alkylaluminum.Examples of the aluminoxane include those in which alkylaluminum is condensed with water.Methylaluminoxane is particularly effective, and has a degree of polymerization of 5 or more, preferably 10 or more. Things are used.

The use ratio of the aluminoxane to the transition metal catalyst component is 10 to 100,000,000 times, usually 50 to 100 times.
5000 mole times. Also, a combination of an alkyl aluminum and a stable anion or a compound generating the same can be used.

The polymerization conditions are not particularly limited, and a solvent polymerization method using an inert medium, a bulk polymerization method substantially free of an inert medium, and a gas phase polymerization method can be used.
In general, the polymerization is carried out at a temperature of -100 to 200 ° C. and at a pressure of normal pressure to 100 kg / cm ² . Preferably, it is -100 to 100 ° C and normal pressure to 50 kg / cm ² .

In the polymerization, ethylene or an α-olefin having 4 or more carbon atoms, for example, butene-1, pentene-1, hexene-1, heptene-1, 4-methylpentene-1 is used in an amount of 10% by weight or less. Copolymerization is possible, and if it is more than 10% by weight, the physical properties of the composition become poor, which is not preferable.

Syndiotactic used in the present invention
Polypropylene is a polypropylene having a syndiotactic pentad fraction of 0.6 or more, preferably 0.7 or more, in a propylene homopolymer. Properties are not sufficient and the physical properties are poor, which is not preferable.

In the case of copolymers with other α-olefins, measurement was made with a 1,2,4-trichlorobenzene solution.
^The peak intensity observed at about 20.2 ppm in ¹³ C-NMR is not less than 0.3, preferably not less than 0.5, of the peak intensity attributed to all methyl groups of the propylene unit. Not preferred. The molecular weight is the intrinsic viscosity measured with a tetralin solution at 135 ° C.
It is about 0.1 to 20, preferably about 0.5 to 10.

The copolymer of ethylene and propylene used in the present invention has an ethylene content of 10 to 95% by weight, particularly 15 to 90% by weight.
% Is outside the above range, there is no effect on improvement of impact resistance. Here, a part of ethylene can be replaced by an α-olefin having 4 or more carbon atoms, but the amount is at most half the amount of ethylene. The molecular weight of the copolymer is 0.1 to 20 dl / g , preferably about 0.5 to 15 dl / g , as the intrinsic viscosity measured with a tetralin solution at 135 ° C. If it is less than 0.1, the effect of improving impact resistance is not obtained, and if it is more than 20, dispersion in syndiotactic polypropylene is poor and impact resistance is poor.

Suitable catalysts for producing the copolymer include, in addition to the above-mentioned catalysts, catalysts which give isotactic polypropylene and atactic polypropylene. A copolymer obtained by polymerizing ethylene and propylene using these materials can be used, the structure of the copolymer is not specified, and the catalyst system and polymerization conditions are not specified.

In the present invention, the quantitative ratio of the syndiotactic polypropylene to the copolymer of ethylene and propylene
The weight ratio is about 30/70 to 98/2, more preferably about 45/55 to 95/5. If it is less than 30/70, the rigidity is poor, and if it exceeds 98/2, the impact resistance is poor.

The composition used for producing the molded article of the present invention can be obtained by mixing the above two components using a kneader capable of mixing well. Also, first polymerize propylene and then copolymerize ethylene and propylene,
It can be produced by a so-called block copolymerization method.

As the kneader used for producing the composition of the present invention, an extruder, an extruder provided with a twin screw, a Banbury kneader and the like can be used. The kneading temperature is 150 to 350 ° C, preferably 180 to 300 ° C.

In the present invention, the above composition is then formed into a sheet, tube, or rod by extrusion. The molding conditions must be relatively slow extrusion conditions of 50 cm / min to 300 cm / min.

In the present invention, extrusion molding is important, and although the reason is not clear, there is a problem that when molded under conditions such as injection molding and press molding, a copolymer appears on the surface of a molded product.

[0021]

The present invention will be further described with reference to examples.

Example 1 Isopropyl (cyclopentadienyl-1-fluorenyl) zirconium obtained by lithiation of isopropylcyclopentadienyl-1-fluorene synthesized according to a conventional method, reaction with zirconium tetrachloride and recrystallization. Using 0.2 g of dichloride and 30 g of methylaluminoxane manufactured by Tosoh Akzo Co., Ltd. (degree of polymerization 16.1), the polymerization pressure was maintained at 3 kg / cm ² -G at 20 ° C. by inserting propylene in an autoclave having an internal volume of 200 liters. Polymerization was performed for 2 hours, followed by decalcification with methanol and methyl acetoacetate, washing with an aqueous hydrochloric acid solution, and filtration to obtain 5.6 kg of syndiotactic polypropylene.

According to ¹³ C-NMR, the polypropylene had a syndiotactic pentad fraction of 0.935, and 135
Intrinsic viscosity measured with tetralin solution at ℃ (hereinafter abbreviated as η)
Is the ratio between the weight average molecular weight and the number average molecular weight measured with 1.45 dl / g , 1,2,4-trichlorobenzene (hereinafter referred to as MW / MN
Abbreviation) was 2.2.

This syndiotactic polypropylene
30 parts by weight of Mitsui Petrochemical Co., Ltd. ethylene-propylene copolymer (ethylene content 73%, Toughma-P0280) was added to 70 parts by weight, and a 30 mmφ extruder (Ikegai PCM30) made by Ikegai Iron Works Co., Ltd. was added. The mixture was kneaded at 210 ° C. (100 rpm) to form pellets. Using these pellets, Osaka Seiki Co., Ltd.
A 200 mm wide die was attached to a 40 mm extruder to form a 2 mm thick sheet.

The following physical properties of this sheet were measured.・ Bending rigidity: kg / cm ² ASTM D747 (23 ° C) ・ Tensile yield strength: kg / cm ² ASTM D638 (23 ° C) ・ Elongation:% ASTM D638 (23 ° C) ・ Izod (with notch) Impact strength: kgcm / cm ASTM D
256 (23 ° C, -10 ° C) Haze:% Conforms to ASTM D1003. Bending stiffness is 3000 kg / cm ^2, the tensile yield strength 165 kg / cm
^{2. The} elongation was 323%, the Izod impact strength was 61 and 64 (23 ° C and -10 ° C, respectively) kg · cm / cm, and the haze was 23%. When the surface was observed after storage at 25 ° C for 30 days, no embossment was observed.

Comparative Example 1 A molded product having a thickness of 2 mm was obtained using the pellets of Example 1 using an injection molding machine manufactured by Komatsu Ltd., and the physical properties were measured in the same manner. The flexural rigidity was 2600 kg / cm ^2. , Tensile yield strength is
157kg / cm ² , elongation 420%, Izod impact strength 6
1, 64 (23 ° C., −10 ° C., respectively) kg · cm / cm, and the haze was 25%. When the surface was observed after storage at 25 ° C. for 30 days, embossment was observed, and the haze was reduced to 72%.

[0027]

The molded article of the present invention has an excellent balance of physical properties and has no problems such as floating on the surface, and is extremely valuable industrially.

────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C08L 23:12 C08L 23:12 23:16 23:16 (56) References JP-A-4-226552 (JP, A) JP JP-A-3-81355 (JP, A) JP-A-3-81356 (JP, A) JP-A-3-81128 (JP, A) JP-A-3-82814 (JP, A) (58) Fields studied (Int) .Cl. ⁷ , DB name) C08J 5/00 C08L 23/12 C08L 23/16

Claims (1)

(57) [Claims] (1) The syndiotactic pentad fraction is:
0.6 or more propylene homopolymer or propylene and other
A copolymer of olefins of the formula
20.2 ppm by ¹³ C-NMR measured with lorobenzene solution
Observed peak intensities in all methyl groups of propylene unit
The peak intensity at which the peak intensity is
0.1-20 as intrinsic viscosity measured with tralin solution
30 to 98 layers of a certain syndiotactic polypropylene
Parts by weight and ethylene (up to half of α-olefin with 4 or more carbon atoms)
An impact-resistant polypropylene molded product obtained by extruding a composition comprising 2 to 70 parts by weight of a copolymer of ethylene and propylene having a content of 10 to 95% by weight .