JP3135304B2 - Impact resistant polypropylene resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an impact-resistant polypropylene resin composition. More specifically, the present invention relates to a polypropylene resin composition substantially comprising a copolymer of polypropylene having a syndiotactic structure and ethylene and propylene, and having a part of the copolymer of polypropylene and ethylene and propylene substantially compatible.

[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. In contrast, JAEWEN et al. For the first time could obtain a polypropylene with good tacticity with a syndiotactic pentad fraction of more than 0.7 using a catalyst consisting of a transition metal catalyst component having an asymmetric ligand and an aluminoxane. (J.Am.Ch
em. Soc., 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.

[0004]

Means for Solving the Problems The present inventors have solved the above problems and have intensively searched for a polypropylene composition having excellent impact resistance, good transparency, and excellent physical balance, and completed the present invention. did.

That is, the present invention relates to 100 to 100 parts by weight of a polypropylene having a substantially syndiotactic structure and copolymers 1 to 100 of ethylene and propylene having a syndiotactic structure having an ethylene content of 10% by weight or more and less than 50% by weight.
1 to 100 parts by weight of a copolymer of ethylene and propylene having an ethylene content of 50 to 95 wt% and a ratio of two ethylene-propylene copolymers of 1: 0.1 to 1:10. Impact-resistant polypropylene resin composition.

Hereinafter, the composition of the present invention will be described in detail by describing a method for producing the composition.

As a catalyst suitable for synthesizing a 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 homopolymer of propylene is produced, the syndiotactic pentad fraction of the resulting polymer (A. Zambelli et al., Macromoleculesvol.
6 687 (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 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 not more than 10% by weight. It is possible to polymerize, 10% by weight
If it is more than this, the physical properties of the composition become poor, which is not preferable.

The term "substantially syndiotactic structure" as used herein means that a homopolymer of propylene has a syndiotactic pentad fraction of 0.6 or more, preferably
If it is greater than 0.7 and less than 0.6,
The properties as crystalline polypropylene are not sufficient and the physical properties are poor, which is not preferable.

In the case of copolymers with other α-olefins, ¹³ C-NM was measured using a 1,2,4-trichlorobenzene solution.
The peak intensity observed at about 20.2 ppm in R 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, and if it is less than 0.3, the physical properties are poor and it is not preferable.

The molecular weight is 0.1 to 20, preferably 0.5, as the intrinsic viscosity measured with a tetralin solution at 135 ° C.
~ 10 or so.

In the present invention, it is important to use a copolymer of ethylene and propylene having an ethylene content of 10% by weight or more and less than 50% by weight and a copolymer of 50 to 95% by weight. 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 copolymer having an ethylene content of 10% by weight or more and less than 50% by weight used in the present invention needs to be well compatible with the above-mentioned polypropylene having the syndiotactic structure. It needs to be racemic. The degree of this racem is two or three when looking at the six monomer units in the polymer chain.
Of propylene in successive racemic fractions, this value
It is preferably 0.5 or more. This structure has ¹³ C-NMR
You can know by. For example, details are given in Polymer, 1988, vol 292208, reported by Asakura et al. The molecular weight of the copolymer is 0.1 to 20 dl / g , preferably about 0.5 to 10 dl / g , as the intrinsic viscosity measured with a tetralin solution at 135 ° C.

As a catalyst suitable for producing the copolymer, when the above-mentioned propylene is polymerized, the obtained polymer has a highly syndiotactic structure and has good copolymerizability with ethylene. And the like. Specifically, the above-mentioned catalyst system is used, and the above-mentioned conditions can be used as it is for the polymerization conditions.

In the present invention, another copolymer must have an ethylene content of 50 to 95% by weight. This component is not compatible with syndiotactic polypropylene and causes phase separation. It has the effect of improving impact resistance. The molecular weight of this copolymer is 135 ° C
0.1-20 dl as intrinsic viscosity measured with tetralin solution of
/ g , preferably about 0.5 to 10 dl / g .

As a catalyst suitable for producing the copolymer, there is no particular limitation on whether the polymer obtained when propylene is polymerized has an isotactic structure, a syndiotactic structure or an atactic structure. Any copolymer can be used as long as it gives a copolymer having a desired ethylene content and a desired molecular weight. As for the polymerization conditions, the above conditions can be used as they are.

In the present invention, the amount ratio of the copolymer to the syndiotactic polypropylene is based on the copolymer of ethylene and propylene having a syndiotactic structure having an ethylene content of 10% by weight or more and less than 50% by weight based on 100 parts by weight of the syndiotactic polypropylene. Two types of ethylene copolymers consisting of 1 to 100 parts by weight of a polymer and 1 to 100 parts by weight of a copolymer of ethylene and propylene having an ethylene content of 50 to 95% by weight.
It is necessary that the ratio of the propylene copolymer be 1: 0.1 to 1:10.

If the amount of the copolymer is too small, there is no effect of improving the impact resistance, and if it is too large, the rigidity becomes poor. Also 2
Quantitative ratio of the kind of copolymer is ethylene content more than 10wt% and 50w
If the amount of the copolymer of ethylene and propylene having a syndiotactic structure that is less than t% is too large, the rigidity is greatly reduced, and the copolymer of ethylene and propylene having an ethylene content of 50 to 95 wt% is too large. However, the effect of improving the impact resistance is small.

The composition of the present invention can be mixed using a kneader capable of mixing the above three components well. Further, it can be produced by a so-called block copolymerization method in which propylene is first polymerized and then ethylene and propylene are copolymerized, but in order to obtain the composition of the present invention, it is preferable to further knead the copolymer. .

As a kneader used for producing the composition of the present invention, a kneader capable of kneading with relatively high strength is preferably used, and an extruder provided with a twin screw, a Banbury kneader and the like are used. it can. The kneading temperature is 150
-350 ° C, preferably 180-300 ° C.

[0024]

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

Example 1 Isopropylcyclopentadienyl-1-fluorene synthesized according to a conventional method in an autoclave having an internal volume of 7 liters was lithiated, reacted with zirconium tetrachloride, and recrystallized to obtain isopropyl (cyclohexane). 15 mg of pentadienyl-1-fluorenyl) zirconium dichloride and methylaluminoxane manufactured by Toso-Akzo Co., Ltd. (degree of polymerization
16.1) Dissolve 2 g in 3 liters of toluene, charge propylene to 4 kg / cm ² -G at 20 ° C, polymerize for 2 hours while adding propylene to 4 kg / cm ² -G and polymerize for 2 hours. 280 g of polypropylene were obtained. The intrinsic viscosity of this polymer measured in 135 ° C tetralin solution is 1.41 dl
/ g and a syndiotactic pentad fraction of 0.923
Met.

After the catalyst was similarly charged using the same apparatus, propylene was added in an amount of 0.5 kg / cm ² -G and ethylene was added in an amount of 3 kg / cm 2.
^2- G was added and polymerization was carried out for 30 minutes. After the polymerization, unreacted monomers were purged, and the solution was poured into a large amount of methanol to precipitate a polymer. 85 g of the obtained polymer had an ethylene content of 38 wt%, an intrinsic viscosity of 0.78, and a racemic fraction of
It was 0.85. A commercially available ethylene-propylene copolymer (ethylene-propylene copolymer manufactured by Mitsui Petrochemical Co., Ltd. (ethylene content: 73 wt%, Tuffma-P0280)) was also used.

Syndiotactic polypropylene 100
Parts by weight, 15 parts by weight of a copolymer having an ethylene content of 38 wt% and 15 parts by weight of a copolymer having an ethylene content of 73 wt% were extruded using a 30 mmφ extruder (Ikegai PCM30) manufactured by Ikegai Ironworks Co., Ltd.
The mixture was kneaded at 100 ° C. (100 rpm) to form pellets. Using these pellets, a 200 mm wide extruder manufactured by Osaka Seiki Co., Ltd.
m die was attached, and a sheet having a thickness of 2 mm was formed.

The following physical properties of this sheet were measured. Flexural ^{stiffness: kg / cm 2 ASTM D747 (} 23 ℃) · Tensile Yield ^{Strength: kg / cm 2 ASTM D638 (} 23 ℃) · elongation:% ASTM D638 (23 ° C.), Izod (notched) impact strength: kg ・ cm ／ cmASTM D
256 (23 ° C, -10 ° C, -30 ° C) Haze:% Conforms to ASTM D1003.

The flexural rigidity is 5600 kg / cm ² , the tensile yield strength is 161 kg / cm ² , the elongation is 420%, and the Izod impact strength is
69, 64, 50 (23 ° C, -10 ° C, -30 ° C respectively) kgcm /
cm and haze was 38%.

Comparative Example 1 The procedure of Example 1 was repeated except that only a copolymer having an ethylene content of 38 wt% was used.
kg / cm ² , tensile yield strength 139 kg / cm ² , elongation 323
%, Izod impact strength 61, 64, 5.4 (23 each
° C, -10 ° C, -30 ° C) kg · cm / cm, haze 35%
Met.

Comparative Example 2 The procedure of Example 1 was repeated except that only a copolymer having an ethylene content of 73 wt% was used.
kg / cm ² , tensile yield strength 161 kg / cm ² , elongation 349
%, Izod impact strength is 69, 75, 15 (23 ° C,
−10 ° C., −30 ° C.) kg · cm / cm, and the haze was 43%.

Example 2 The procedure of Example 1 was repeated except for using 10 parts by weight of a copolymer having an ethylene content of 38 wt% and 20 parts by weight of an ethylene content of 73 wt%. 5800kg /
cm ² , tensile yield strength 182 kg / cm ² , elongation 410%, Izod impact strength 69, 64, 55 (23 ° C, -10
° C, -30 ° C) kg · cm / cm, and the haze was 37%.

[0033]

The copolymers and compositions of the present invention are excellent in impact resistance and extremely excellent in balance of physical properties.
It is extremely valuable industrially.

Claims (1)

(57) [Claims] 1. 100 parts by weight of a polypropylene having a substantially syndiotactic structure and an ethylene content of 10 wt.
% To less than 50 wt% of a copolymer of ethylene and propylene having a syndiotactic structure and 1 to 100 parts by weight of a copolymer of ethylene and propylene having an ethylene content of 50 to 95 wt%. An impact-resistant polypropylene resin composition, wherein the ratio of the ethylene-propylene copolymer is from 1: 0.1 to 1:10.