JP2785607B2 - Ethylene-propylene block copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ethylene-propylene block copolymer excellent in rigidity, impact resistance, tensile properties, heat resistance and the like.

[0002]

2. Description of the Related Art Polypropylene has excellent properties,
Since they are relatively inexpensive, they are widely used in daily necessities, home appliances, automobile parts, industrial parts and the like, but molded articles are becoming thinner with increasing size and weight. For this reason, a highly fluid polypropylene or polypropylene resin composition having excellent heat resistance, rigidity and impact resistance has been demanded. Hitherto, many polypropylene compositions have been proposed in which crystalline polypropylene is mixed with rubber-like properties such as polyethylene or amorphous ethylene-propylene copolymer in order to improve these disadvantages. In addition, in order to improve the rigidity and heat resistance decrease due to the addition of a rubber-like substance,
Many compositions containing an inorganic filler such as talc have been proposed. However, the addition of the rubber-like substance or the inorganic filler significantly lowers the melt fluidity, generates a striped pattern, which is a so-called flow mark, peculiar to the injection molded article, and also deteriorates the strength and appearance of the weld portion. As a method for improving the melt fluidity, there is known a method in which a small amount of an organic peroxide is added to polypropylene having a low melt fluidity or a composition thereof, followed by heat treatment. However, polypropylene obtained by such a method suffers from problems of stiffness reduction, odor caused by heat treatment, and strong flow marks on the surface of the injection molded body when the composition contains a rubber-like substance or an inorganic filler. There are problems such as poor appearance. Therefore, development of polypropylene excellent in rigidity, impact resistance, melt fluidity and the like without the need for such heat treatment is strongly desired. So-called block copolymers are known as polypropylene having good rigidity and impact resistance, but home appliance parts which require high impact resistance, especially low-temperature impact resistance, rigidity and heat resistance, As an automobile outer panel material or interior material, the balance of fluidity, rigidity and impact strength is still insufficient.

[0003]

SUMMARY OF THE INVENTION In view of the state of the prior art, the present invention is excellent in rigidity, impact strength and melt flowability.
Another object of the present invention is to provide an ethylene-propylene block copolymer having good appearance of a molded article.

[0004]

According to the present invention, there is provided a propylene homopolymer or a polypropylene portion obtained by copolymerizing propylene and ethylene or an α-olefin having 4 or more carbon atoms of 1 mol% or less, and a composition of ethylene and propylene in a weight ratio. Having an ethylene-propylene random copolymer portion wherein ethylene / propylene is 20/80 to 60/40,
(1) Intrinsic viscosity [η] _{P of the} polypropylene part is 0.8
2.0 dl / g, the ratio Q value (weight average molecular weight M _w / number average molecular weight M _N ) of the molecular weight measured by GPC is 3.0 to 3.0.
5.0, the xylene-soluble content at 20 ° C. is 1.5% by weight or less,
(2) an ethylene-propylene block copolymer having an intrinsic viscosity [η] _EP of 3.5 to 8.5 of the ethylene-propylene random copolymer portion and (3) 5 to 20% by weight of the whole polymer. It is united.

The ethylene-propylene block copolymer in the present invention is a propylene homopolymer or a copolymer of propylene and ethylene or an α-olefin having 4 or more carbon atoms (for example, butene-1, hexene-1, etc.) in an amount of 1 mol% or less. And the composition of ethylene and propylene in a weight ratio of ethylene / propylene = 20/80
It has an ethylene-propylene random copolymer portion of 60 to 40/40, and contains the ethylene-propylene random copolymer portion in an amount of 5 to 20% by weight of the whole polymer.

The above-mentioned block copolymer is usually obtained by two-stage polymerization in the presence of a Ziegler-Natta catalyst by a combination of titanium trichloride and an alkylaluminum compound. It is preferable to use a catalyst composed of a complex of magnesium and magnesium, a trialkylaluminum compound and an electron-donating organic compound.

A method for producing this catalyst is described in, for example,
No. 218606 and the like. That is,
(A) In the presence of a silicon compound having a Si—O bond,
General formula Ti (OR ¹)_nX_4-n(R¹Has 1 to 20 carbon atoms
A hydrocarbon group, X is a halogen atom, and n is a positive number 0 <n ≦ 4.
The titanium compound represented by
The solid product obtained by reduction with the compound is an ester compound
And a mixture of an ether compound and titanium tetrachloride.
A trivalent titanium compound-containing solid catalyst component obtained by
(B) Organoaluminum compound, (C) Si-OR^TwoConclusion
(R^TwoHaving 1 to 20 carbon atoms)
Homopolymerization of propylene using an iodine compound catalyst
Alternatively, it can be obtained by copolymerization.

The silicon compound having a Si—O bond is
It is represented by the following general formula. Si (OR ³ )
_{^{m R 4 4-m, R}} 5 (R 6 SiO) P SiR 7 3 or (R
⁸ ₂ SiO) _q wherein R ³ is a hydrocarbon group having 1 to 20 carbon atoms, and R ⁴ , R ⁵ , R ⁶ , R ⁷ and R ^{8 each} have 1 to 2 carbon atoms.
0 hydrocarbon group or hydrogen atom, m is a number 0 <m ≦ 4,
p is an integer of 1 to 1000, and q is an integer of 2 to 1000. Specific examples of the organosilicon compound include tetramethoxysilane, dimethyldimethoxysilane, diethoxydiethylsilane, diethoxydiphenylsilane, triethoxyphenylsilane, cyclohexyl-ethyldimethoxysilane, and phenyltrimethoxysilane.

As the organomagnesium compound, any type of organomagnesium compound containing a magnesium-carbon bond can be used. In particular, a Grignard compound represented by the general formula R ⁹ MgX (R is a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen) and a general formula R ¹⁰ R ¹¹ Mg (R ¹⁰ ,
R ¹¹ is a dialkyl magnesium or diaryl magnesium compound represented by a hydrocarbon group) having 1 to 20 carbon atoms are preferably used. Here, R ¹⁰ and R ¹¹ may be the same or different.

Examples of the ester compound include mono- and polyvalent carboxylic esters such as aliphatic carboxylic esters, olefin carboxylic esters, alicyclic carboxylic esters and aromatic carboxylic esters. Among these ester compounds, olefin carboxylic acid esters such as methacrylic acid esters and maleic acid esters, and phthalic acid esters are preferable, and diesters of phthalic acid are particularly preferable.

As the ether compound, dialkyl ethers such as diethyl ether, di-n-propyl ether, diisopropyl ether, dibutyl ether, diamyl ether and methyl-n-butyl ether are preferable, and di-n-butyl ether, di-n-butyl ether and di-n-butyl ether are particularly preferable. Isoamyl ether is preferred.

In the polymerization, the ratio of the organoaluminum compound to the titanium compound / magnesium compound complex is 3/1.
It can be selected in the range of ２０20/1. Also Si-OR
The ratio of the silane compound having ^two bonds to the titanium compound / magnesium compound complex can be selected in the range of 1/10 to 1/2 (mol / mol).

The ethylene-propylene block copolymer of the present invention comprises the following components (I) and (II). (I) The crystalline polypropylene part has (1) an intrinsic viscosity [η] _p in tetralin at 135 ° C. of 0.8 to 2.0 dl.
/ G, preferably 0.8 to 1.7 dl / g, more preferably 0.85 to 1.5 dl / g, and (2) G
Q value (weight average molecular weight M _w / number average molecular weight M _N ) measured by PC is 2.5 to 5.5, preferably 3 to 5,
And (3) accounts for 95 to 80% by weight of the total copolymer amount, and (II) an ethylene-propylene random copolymer portion has
(1) Intrinsic viscosity [η] _{EP in} tetralin at 135 ° C. is 3.5 to 8.0 dl / g, preferably 3.5 to 7.0 d.
1 / g, (2) ethylene and propylene composition in weight ratio of 2
0/80 to 60/40 (weight ratio), and (3)
It accounts for 95 to 80% by weight of the total copolymer amount.

The ethylene-propylene block copolymer is produced by the above two steps (I) and (II) by a slurry polymerization method or a gas phase polymerization method. The slurry polymerization method is preferred. If (η) _p of (I) is smaller than 0.8 dl / g, the mechanical strength is reduced, and if it is 2.0 dl / g or more, the melt fluidity of the ethylene-propylene block copolymer and its composition is reduced. descend. Q value is 5.5
If it is more than the above, a weld line of an injection-molded article obtained from the ethylene-propylene block copolymer and its composition appears strongly, and if it is 3 or less, a flow mark is generated.
If the intrinsic viscosity [η] _{EP of} (II) is 3.5 dl / g or less, the impact resistance is low, and if it is 8.0 dl / g or more, the melt fluidity decreases and the dispersion of the constituent components of the composition is poor. The impact resistance is reduced. Further, when the ethylene content in the ethylene-propylene random copolymer is 20% by weight or less, or 60% by weight or more, the impact resistance of the molded article is deteriorated, which is not preferable.

The resin of the present invention may be used alone or
-Used as a composition containing an olefin rubber and an inorganic filler. When blending an inorganic filler or the like, the crystalline ethylene-propylene block copolymer of the present invention is 50% by weight or more, the inorganic filler is 5 to 40% by weight, and / or the ethylene-α-olefin random copolymer rubber 5 ~
It contains 40% by weight. That is, the composition can have the following compositions (1), (2), and (3). (1) Crystalline ethylene-propylene block copolymer: 50 to 95% by weight Inorganic filler: 5 to 40% by weight (2 ) Crystalline ethylene-propylene block copolymer: 50 to 95% by weight Ethylene-α-olefin random copolymer rubber: 5 to 40% by weight (3) Crystalline ethylene-propylene block copolymer・ 50 to 95% by weight Inorganic filler 5 to 40% by weight Ethylene-α-olefin random copolymer rubber 5 to 40% % By weight However, the total of each component is 100% by weight.

As the inorganic filler, talc, mica, calcium carbonate, wollastonite, glass fiber and the like are used. Among these inorganic fillers, talc having an average particle size of 4.0 μm or less, preferably 3.5 μm to 1.0 μm, in consideration of the effect of improving rigidity and appearance.
When the thickness is 4.0 μm or more, the impact strength of the molded product is reduced, and when the thickness is 1.0 μm or less, it is not preferable because it lacks practicality. The amount of talc used is 5 to 40% by weight, preferably 10 to 35% by weight. When the amount is 5% by weight or less, the effect of improving rigidity is small, and when the amount is 40% by weight or more, impact resistance is undesirably reduced.

The ethylene-α-olefin random copolymer rubber has an ethylene content of 85% by weight to 40% by weight,
It is preferably 85% by weight to 65% by weight, and a Mooney viscosity ML _{1 + 4} measured at 121 ° C. of 15 to 80, preferably 20 to 70, and an iodine value of 0 to 15 is suitably used. If the ethylene content is 40% by weight or more, the rigidity of the molded article is greatly reduced, and the ethylene content is 85% by weight.
If it is above, the effect of improving the impact resistance is small. If the Mooney viscosity exceeds 70, the fluidity of the composition will decrease, or the impact strength will decrease due to poor dispersion of the rubber particles.
On the other hand, if the Mooney viscosity is 10 or less, the dispersion particle size of the rubber in the composition is too small, so that the effect of improving the impact resistance is small, and the surface of the injection molded article is not preferred.

Specific examples of the α-olefin copolymerized with ethylene include propylene, 1-butene, 4-methyl-pentene-1, 1-hexene and the like.
Propylene or 1-butene is preferred. The ethylene-α-olefin random copolymer rubber is copolymerized with a small amount of a non-conjugated diene monomer such as ethylidene norbornene, dicyclopentadiene, 1,4-hexadiene in an iodine value of 0 to 15, preferably about 0 to 10. It may be. These ethylene-α-olefin copolymer rubbers can be used alone or in admixture of two or more in accordance with the respective purposes such as fluidity of the composition, impact strength and hardness of a molded article. The amount used is 5 to 40% by weight, preferably 5 to 40% by weight.
An amount of ~ 35% by weight is incorporated. If this ethylene-α-olefin random copolymer is 5% by weight or less, the effect of improving impact resistance is small, and if it exceeds 40% by weight, the rigidity is greatly reduced, which is not preferable.

The ethylene-α-olefin random copolymer rubber is usually polymerized in a hydrocarbon solvent in the presence of a catalyst comprising a vanadium compound and an organoaluminum compound. As the vanadium compound, vanadium oxytrichloride, vanadium tetrachloride, vanadate compound, and as the organoaluminum compound, ethyl aluminum sesquichloride, diethyl aluminum chloride or the like is used, and is polymerized in a solvent such as hexane or heptane. Manufactured.

The composition of the present invention is obtained by mixing an ethylene-propylene block copolymer, an ethylene-α-olefin random copolymer rubber and / or an inorganic filler with a tumbler, Henschel mixer, ribbon blender or the like.
It can be manufactured by melt-kneading with a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneader or the like. By using an extruder having excellent kneading performance, such as a twin-screw extruder, a Banbury mixer, or a kneader, a high-quality composition in which each component is uniformly dispersed can be obtained. The kneading of each component may be performed simultaneously, or may be performed separately. As a method of kneading by dividing, a method of kneading an ethylene-propylene block copolymer and talc and then adding an ethylene-α-olefin random copolymer rubber, or a part of the ethylene-propylene block copolymer , A method of premixing an ethylene-α-olefin random copolymer rubber into a masterbatch and kneading it separately with a crystalline ethylene-propylene block copolymer and an inorganic filler, an ethylene-propylene block copolymer , Knead crystalline polypropylene and talc to a high concentration to form a masterbatch, which is separately kneaded with ethylene-propylene block copolymer, crystalline polypropylene and ethylene-α-olefin random copolymer rubber, etc. Is done.

Furthermore, in addition to the basic components of these compositions,
Contains additives such as antioxidants, ultraviolet absorbers, lubricants, antistatic agents, copper damage inhibitors, flame retardants, neutralizers, nucleating agents, foaming agents, plasticizers, pigments, dyes, etc. according to their purposes You can do it. Among these additives, it is desirable to add an antioxidant or an ultraviolet absorber in order to improve heat resistance, weather resistance and oxidation resistance stability.

The ethylene-propylene block copolymer of the present invention and the composition thereof are excellent in rigidity, impact resistance and melt fluidity, and the appearance of the molded article is good, but the injection molding method and press molding It is molded by a method and is suitably used for automobile home panels, automobile interior applications, and large home appliance parts such as washing tubs.

The ethylene-propylene block copolymer of the present invention is produced by such a method.
When used for applications requiring rigidity, scratch resistance, gloss, etc., the isotactic pentad fraction of the boiling heptane-insoluble portion of the crystalline polypropylene portion polymerized in the first stage is 0.970 or more, and the boiling heptane It is preferable to use a highly crystalline polypropylene having a soluble part content of 5.0% by weight or less and a xylene soluble part content of 20 ° C. of 1.5% by weight or less. The isotactic pentad fraction of the boiling heptane-insoluble part, the content of the boiling heptane-soluble part, and the content of the polymer soluble in xylene at 20 ° C. are determined as follows. After completely dissolving 5 g of crystalline polypropylene in 500 ml of boiling xylene, the temperature is lowered to 20 ° C. and left for 4 hours. Thereafter, this is separated by filtration, and the xylene-insoluble portion at 20 ° C. is separated. The filtrate is concentrated and dried to evaporate xylene and further dried at 60 ° C. under reduced pressure to obtain a polymer soluble in xylene at 20 ° C. The value obtained by dividing the dry weight by the weight of the charged sample and expressed as a percentage is the content of the xylene-soluble portion at 20 ° C. 20
The xylene-insoluble part is dried and then subjected to Soxhlet extraction with boiling n-heptane for 8 hours. This extraction residue is referred to as a boiling heptane-insoluble part, and a value obtained by dividing the value obtained by subtracting the dry weight from the charged sample weight (5 g) by the charged sample weight and expressing the result in percentage is the content of the boiling heptane-soluble part. is there.

The isotactic pentad fraction is
A. Macromolec by Zambelli et al.
ules, 6 , 925 (1973), ie, isotactic linkage in pentad units in crystalline polypropylene molecular chains measured using ¹³ C-NMR, in other words, propylene monomer units. 5
It is the fraction of propylene monomer units at the center of a chain of meso-bonds that are consecutively formed. However, regarding the assignment of NMR absorption peaks, Macromole published afterwards
cules, 8 , 687 (1975). Specifically, the isotactic pentad fraction is measured as the area fraction of the mmmm peak among all the absorption peaks in the methyl carbon region of the ¹³ C-NMR spectrum.
In this way, the UK National Physica
L LABORATORY NPL Reference Material CRM N
o. M19-14 PolypropylenePP /
It was 0.940 when the isotactic pentad fraction of MWD / 2 was measured.

[0025]

EXAMPLES The present invention will be described below with reference to examples, but these are merely examples, and the present invention is not limited to these examples unless departing from the gist.

Next, methods for measuring physical properties in the examples will be described below. (1) GPC measurement conditions The measurement was carried out by gel permeation chromatography (GPC) under the following conditions. The calibration curve was prepared using standard polystyrene. Model: 150CV type manufactured by Millipore Waters Co., Ltd. Column: Shodex M / S 80 Measurement temperature: 145 ° C, solvent ortho-dichlorobenzene Sample concentration: 5 mg / 8 ml Note that NBS (National Bureau of Standard) was used under these conditions.
s) Standard Reference Material 706 (Mw / M
As a result, the molecular weight distribution (Q value) Mw / Mn = 2.1 was obtained.

(2) Melt flow rate (MFR) According to a method specified in JIS K6758. The measurement temperature is 230 ° C. and the load is measured at 2.16 kg. (3) Tensile test According to the method specified in ASTM D638. A test piece molded by injection molding is used. The thickness of the test piece is 3.2 mm, and the tensile yield point strength is evaluated. The measurement temperature is 23 ° C. (4) Bending test According to the method specified in JIS K7203. A test piece molded by injection molding is used. The thickness of the test piece is 6.4 mm, and the flexural modulus and the bending strength are evaluated under the conditions of a span length of 100 mm and a load speed of 2.0 mm / min. The measurement temperature is 23 ° C. (5) Izod impact strength According to the method specified in JIS K 7110. A test piece molded by injection molding is used. The thickness of the test piece is 6.
It is 4 mm, and the notched impact strength that is notched after molding is evaluated. Measurement temperature is -20 ℃ and -30 ℃
It is. (6) Appearance The appearance of the following three types of molded articles was visually evaluated. Good: Good, Normal: Poor, Poor: Flow mark: A stripe pattern probably due to a difference in gloss that is likely to be formed at a portion away from the gate of the molding machine. Weld line: A linear pattern that is likely to occur at the junction of resins during molding. Smoothness: unevenness seen on a plane other than the weld line. (7) Gloss According to the method specified in JIS Z8741. The measurement temperature is 23 ° C., the thickness is 3 mm, and the incident angle and the reflection angle are each 60 °.

(8) Production of Composition The composition was produced under the following conditions. After weighing a predetermined amount of each component and premixing uniformly with a Henschel mixer,
Continuous twin screw kneader (TEX 44 SS 30BW-2 manufactured by Japan Steel Works, Ltd.)
V type), the extrusion rate was 30 kg / hour, the resin temperature was 220 ° C., the screw rotation speed was 350 rotations / minute, and the suction was performed under vent suction. The screw was constructed by arranging a triple-type rotor and a kneading disk in two kneading zones, each in a zone next to the first feed port and the second feed port. Was seen.

(9) Injection molding conditions of flat plate Injection molding machine Sumitomo Heavy Industries Neomat 515/150 Cylinder temperature NH H1 H2 H3 H4 220 220 220 220 210 200 (° C.) Injection pressure Primary pressure 65 kg / cm ² G Mold temperature 50 ° C. Injection time / cooling time 15/30 (second) Molded product shape (mm) 100 (width) x 400 (length) x 3 (thickness)

Example 1 SUS with 5.5 m ³ stirrer and jacket
After sufficiently replacing the reactor with propylene, 2.5 m ^{3 of} n-heptane, 10 mol of triethylaluminum and 1.5 mol of cyclohexylethyldimethoxysilane were supplied, and the internal temperature was 20 to 40 ° C. and the pressure was 0 to propylene. After adjusting to 0.2 kg / cm ² G, 0.12 kg of a solid catalyst component (synthesized by the method described in Example 1 of JP-A-1-319508) is supplied. Next, warm water was passed through the jacket to raise the internal temperature of the reactor to 75 ° C., and then the reaction pressure was increased to 8 kg / cm ² G with propylene and hydrogen to initiate polymerization. Reaction temperature 8kg / c at reaction temperature 75 ℃
Propylene was continuously supplied so as to maintain m ² G, and polymerization of the crystalline polypropylene portion (hereinafter abbreviated as “P”) was continued while supplying hydrogen so as to maintain the hydrogen concentration in the gas phase at 4.6%. . When the integrated amount of propylene reaches 1180 kg, supply of propylene and hydrogen is stopped, unreacted monomers in the reactor are degassed, and the pressure in the reactor is reduced to 0.1 kg.
The pressure was reduced to 5 kg / cm ² G, and the temperature in the reactor was adjusted to 60 ° C. As a result of sampling and analyzing about 100 g of the polymer in the P part, the intrinsic viscosity [η] _P was 1.02 d
1 / g, the ratio of the molecular weights determined by GPC, M _w / M
_n was 3.5 and the xylene solubles at 20 ° C. were 1.2% by weight. The amount of polymer produced in Part P was 846 kg, calculated from the integrated amount of propylene supplied and the weight of unreacted propylene at the end of the polymerization.

Subsequently, the reaction pressure was raised to 3 kg / cm ² G with propylene and ethylene to start polymerization of an ethylene-propylene copolymer part (hereinafter abbreviated as EP part). / Cm ² G, a mixed gas of propylene / ethylene = 3/1 (weight ratio) is continuously supplied so that the hydrogen concentration in the gas phase is 0.01%.
%, While the polymerization of the EP part was continued while adjusting so as to be maintained at the same level. Propylene / ethylene mixed gas supply integrated amount is 18
At the time of reaching 8 kg, the supply of the monomer was stopped, the entire amount of the polymer slurry in the reactor was led to a deactivation tank, and deactivation treatment was performed with butyl alcohol. The powder was collected and dried with a dryer to obtain 940 kg of a powdery white powder.
The intrinsic viscosity [η] _T of the entire polymer obtained is 1.54
dl / g, and the ethylene content was 2.3% by weight. The polymerization ratio of the P part and the EP part is calculated from the weight of the finally obtained polymer and the amount of the polymer in the P part, and is calculated as 8 by weight.
9/11. Therefore, the ethylene content in the polymer in the EP portion was 24% by weight, and the intrinsic viscosity [η] _EP of the EP portion was 6.2 dl / g.

To 100 parts by weight of the obtained ethylene-propylene block copolymer, 0.05 parts by weight of calcium stearate and 2,6-di-tert-butyl-4-as a stabilizer were added.
0.2 parts by weight of hydroxytoluene (BHT, manufactured by Sumitomo Chemical), tetrakis [methylene-3 (3 ′, 5′-t-butyl-4-hydroxyphenyl) propionate] methane (Irganox 1010, manufactured by Ciba-Geigy) 0.
1 part by weight, and as a nucleating agent, 0.15 parts by weight of aluminum p-tert-butylbenzoate was added.
After pelletizing using a continuous twin-screw kneader, test pieces were prepared by injection molding and physical properties were measured. Table 1 shows the evaluation results. The rigidity, mechanical properties such as impact strength at low temperature and elongation at break, fluidity, and appearance of the molded product were good.

Comparative Example 1 SUS with a stirrer of 5.5 m ³ in internal volume and a jacket
After sufficiently replacing the reactor with propylene, 2.7 m ^{3 of} n-heptane, 10 mol of diethylaluminum chloride and 1.0 mol of ε-caprolactone were supplied, the internal temperature was further adjusted to 20 to 40 ° C., and propylene was added. Pressure to 0.
The solid catalyst component was adjusted to ² kg / cm ² G (JP-A-60
(Synthesized by the method shown in Example-1 of -228504)
Supply 0.58 kg. Next, warm water was passed through the jacket to raise the internal temperature of the reactor to 50 ° C., and then the reaction pressure was increased to 9 kg / cm ² G with propylene and hydrogen to initiate polymerization. At a reaction temperature of 50 ° C. and a reaction pressure of 9 kg / cm ²
Propylene was continuously supplied so as to maintain G, and polymerization was continued in the P part while supplying so as to maintain the hydrogen concentration in the gas phase at 30%. The integrated amount of propylene supply is 1120 kg
, The supply of propylene and hydrogen was stopped, the unreacted monomer in the reactor was degassed, and the pressure in the reactor was reduced to 0.5 kg / cm ² G. As a result of sampling and analyzing about 100 g of the polymer in the P part, the intrinsic viscosity [η] _p was 1.38 dl / g, the molecular weight ratio _Mw / _Mn determined by GPC was 6.1, and xylene at 20 ° C. The soluble matter was 2.5% by weight. The amount of polymer produced in Part P was 735 kg, calculated from the integrated amount of propylene supplied and the weight of unreacted propylene at the end of the polymerization.

Subsequently, the reaction pressure was increased to 3 kg / cm ² G with propylene and ethylene to initiate the polymerization of the EP part. At a reaction temperature of 50 ° C. and a reaction pressure of 3 kg / cm ²
The mixed gas of propylene / ethylene = 2.5 / 1 (weight ratio) is continuously supplied so as to maintain G, and the EP part is adjusted while maintaining the hydrogen concentration in the gas phase part at 0.2%. The polymerization of was continued. When the cumulative supply amount of the propylene / ethylene mixed gas reached 170 kg, the supply of the monomer was stopped, the entire amount of the polymer slurry in the reactor was led to a deactivation tank, and deactivation treatment was performed with butyl alcohol. The solid polymer is recovered by centrifuging the slurry and dried with a drier to obtain a powdery white powder 875.
kg. The intrinsic viscosity [η] _T of the obtained ethylene-propylene block copolymer was 2.18 dl / g, and the ethylene content was 4.5% by weight. The polymerization ratio of the P part and the EP part was 84/16 in terms of a weight ratio calculated from the weight of the finally obtained ethylene-propylene block copolymer and the amount of the polymer in the P part. Accordingly, the ethylene content in the polymer in the EP portion was 28% by weight, and the intrinsic viscosity [η] _EP was 6.4 dl / g.

The obtained propylene-ethylene block copolymer was kneaded and granulated under the same conditions as in Example 1. However,
As the polypropylene component, 70% by weight of the ethylene-propylene block copolymer, intrinsic viscosity [η] =
1.35, 30% by weight of homopolypropylene with Q = 6.3
Was used so that the EP content was the same as in Example 1. The Q value of the P portion is high, the weld appearance is poor, and the elongation at break is low.

Comparative Example 2 An ethylene-propylene block copolymer was polymerized in the same manner as in Example 1. However, the hydrogen concentration was increased during the polymerization of the EP part to obtain an ethylene-propylene block copolymer having an intrinsic viscosity [η] _EP = 2.8 of the EP part. For this copolymer, pellets of the polypropylene composition were obtained in the same manner as in Example 1, and a test piece was prepared by injection molding, and the physical properties and appearance of the composition were evaluated. [Η] Low _{EP and} low impact strength.

Example 2 The hydrogen concentration in the reactor was set to make [η] _p and [η] _EP to predetermined values, and the propylene / ethylene feed ratio was set to make the ethylene content in EP a predetermined amount. Was carried out in the same manner as in Example 1 except that was changed. Thus [η] _p =
1.11, Q value of crystalline polypropylene part = 3.6, 2
The xylene soluble part at 0 ° C. is 1.2% by weight, [η] _EP = 4.
2. EP part 12% by weight, EP part ethylene content 37%
Of propylene-ethylene block copolymer was obtained. The same stabilizer and nucleating agent as in Example 1 were added to this propylene-ethylene block copolymer, melt-kneaded and pelletized as in Example 1, and a test piece was prepared by injection molding to obtain physical properties. Was measured.

Comparative Example 3 The hydrogen concentration in the reactor was set so that [η] _p and [η] _EP were set to predetermined values, and the propylene / ethylene feed ratio was set in order to set the ethylene content in EP to a predetermined amount. Was carried out in the same manner as in Example 1, except that [η] _p = 1.13,
Q value of crystalline polypropylene part = 3.5, xylene soluble part at 20 ° C. is 1.2% by weight, [η] _EP = 2.5, EP part 1
A propylene-ethylene block copolymer having an ethylene content of 2% by weight and an EP part of 41% was obtained. This propylene-
The same stabilizer and nucleating agent as in Example 1 were added to the ethylene block copolymer, and the mixture was melt-kneaded as in Example 1 to obtain an MF.
After forming pellets of R = 31, test pieces were prepared by injection molding and physical properties were measured.

Example 3 A polymerization reaction was carried out in the same manner as in Example 1. Where [η] _p ,
[Η] The hydrogen concentration in the reactor is controlled to make _EP a predetermined value, and the propylene / ethylene feed ratio is controlled to make the ethylene content in EP a predetermined amount.
The supply amount of the propylene / ethylene mixed gas was controlled to make the P content a predetermined amount. Thus, [η] _p
= 0.83, Q value = 3.5, CXS = 1.1% by weight,
[Η] _EP = 4.2, a propylene-ethylene block copolymer having an EP part of 16% by weight and an ethylene content of the EP part of 42% by weight was obtained. 87 parts by weight of the copolymer, having an average particle size of 2.
17 parts by weight of 5 μl of talc and the additive added in Example 1 were melt-kneaded to obtain a polypropylene / talc composite. As shown in Table 1, the fluidity, rigidity and impact strength were excellent.

Comparative Example 4 A polymerization reaction was carried out in the same manner as in Comparative Example 1. Where [η] _p ,
[Η] The hydrogen concentration in the reactor is controlled to make _EP a predetermined value, and the propylene / ethylene feed ratio is controlled to make the ethylene content in EP a predetermined amount.
The supply amount of the propylene / ethylene mixed gas was controlled to make the P content a predetermined amount. The obtained propylene-ethylene block copolymer ([η] _p = 1.60,
Q value = 5.6, CXS = 2.7% by weight, [η] _EP = 5.
0, EP part 19% by weight, ethylene content of EP part 28
%), And 17 parts by weight of talc having an average particle size of 2.5 μm and additives were added thereto, and further, a small amount of Samperox TY-13 was added to improve the fluidity, followed by melt-kneading. Thus, a polypropylene / talc composite material having an MFR of 70 was obtained. As shown in Table 1, the rigidity was inferior to Example 3. Also, the flow mark is noticeable on the molded product,
The appearance was poor.

Example 4 Polymerization was carried out in the same manner as in Example 1. However, the water in the reactor
Element concentration, propylene / ethylene feed ratio, propylene
/ Η by changing the supply amount of the ethylene mixed gas, [η] _p= 1.
75, Q value of the crystalline polypropylene part = 3.6, CXS
Content 1.2% by weight, [η]_EP= 4.1, EP part 16 weight
%, Propylene-ethylene having an ethylene content of 41% in the EP part
A ren block copolymer was obtained. This propylene-ethylene
The same stabilizer as in Example 1 was added to the unblock copolymer
After pelletizing by melt-kneading, injection molding
To obtain a test piece.

Comparative Example 5 Polymerization was carried out in the same manner as in Example 1. However, by changing the hydrogen concentration in the reactor, the propylene / ethylene feed ratio, and the supply amount of the propylene / ethylene mixed gas, [η] _p = 1.7
8. A propylene-ethylene block having a crystalline polypropylene part having a Q value of 3.6, a CXS content of 1.1% by weight, [η] _EP = 3.0, an EP part having an ethylene content of 40%, and an EP content of 16% by weight. A copolymer was obtained. This propylene-ethylene block copolymer was added with the same stabilizer as in Example 4, pelletized by melt kneading, and then a test piece was obtained by injection molding.

[0043]

[Table 1]

[0044]

According to the ethylene-propylene block copolymer and the composition of the present invention, it is possible to obtain a molded article having excellent low-temperature impact strength, rigidity and fluidity and good appearance.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-41316 (JP, A) JP-A-63-191809 (JP, A) JP-A-1-319508 (JP, A) JP-A-4- 279617 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08F 293/00-297/08

Claims (1)

(57) [Claims] 1. The composition of ethylene / propylene in a weight ratio of propylene homopolymer or a crystalline polypropylene portion in which propylene and ethylene or an α-olefin having 4 or more carbon atoms are copolymerized in an amount of 1 mol% or less is ethylene / propylene = 20. / 80-60 / 40, having an ethylene-propylene random copolymer portion, (1) the intrinsic viscosity [η] _{P of the} crystalline polypropylene portion is 0.8-2.0 dl / g, and the molecular weight measured by GPC (Weight average molecular weight M _w / number average molecular weight M _N ) is 3.
0-5.0, the xylene-soluble component at 20 ° C. is 1.5% by weight or less, (2) the intrinsic viscosity [η] _{EP of the} ethylene-propylene random copolymer portion is 3.5-8.5, and (3) An ethylene-propylene block copolymer in which the ethylene-propylene random copolymer portion is 5 to 20% by weight of the whole polymer.