JPS6234056B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing polypropylene compositions having good stiffness, impact resistance and gloss. Although crystalline polypropylene has excellent rigidity and heat resistance, it has the disadvantage of low impact strength, particularly low impact resistance at low temperatures. It is well known that in order to improve this drawback, polypropylene is mixed with an ethylene-propylene copolymer or with polyethylene. However, according to the conventionally proposed techniques, it has generally been difficult to obtain a composition with a good balance between rigidity and impact resistance. Such compositions also typically had greatly reduced gloss compared to plain polypropylene. In order to more easily obtain a composition with well-balanced rigidity and impact resistance, a so-called block copolymerization method is known in which polypropylene and ethylene-propylene copolymer or both polyethylene and polypropylene are produced in one polymerization vessel. has achieved results. However, in this method, the composition is recovered as an insoluble substance in the polymerization medium, but due to the large dissolution loss of the ethylene-propylene copolymer in the polymerization medium or the viscosity of the polymerization liquid, the composition is recovered as an insoluble material. There are deficiencies in the manufacturing method, such as the difficulty in widely changing the properties of the polymer or greatly increasing the amount of the copolymer blended. Furthermore, this method had the disadvantage that it was difficult to obtain a composition with excellent gloss as described above. In view of the current situation, the present inventors investigated a method for easily obtaining a composition with a good balance between impact resistance and rigidity using a mixing method, and also had good gloss. We have discovered a method using polymers. That is, the present invention provides (A) based on 100 parts by weight of polypropylene, (B) (i) a propylene content of 30 to 85 mol %, (ii) a microisotacticity of 3 propylene chains of 0.8 or more, and (iii) Boiling cyclohexane insoluble matter is 10% by weight or less, 1 to 30 parts by weight of a propylene/ethylene random copolymer obtained by polymerization in the absence of the above polypropylene, and (C) 0 to 30 parts by weight of polyethylene. This is a method for producing a polypropylene composition characterized by mixing. The polypropylene (A) used in the present invention is a propylene homopolymer or a copolymer of propylene and other α-olefins, such as ethylene or 1-butene (usually having a propylene unit content of 90 mol% or more). ), and the insoluble matter in boiling n-heptane is 90
% or more, preferably 93% or more. Such polypropylene (A) can typically be produced using a catalyst formed from a solid titanium catalyst component and an organometallic compound component, or a catalyst formed from both of these components and an electron donor. Typical examples of solid titanium catalyst components include titanium trichloride or titanium trichloride compositions produced by various methods, or magnesium, halogen, an electron donor, preferably an aromatic carboxylic acid ester or an alkyl group-containing ether, and titanium as essential components. The catalyst component is a supported titanium catalyst component having a specific surface area of preferably 100 m ² /g or more. Particularly suitable is one produced using the latter supported catalyst component. As the organometallic compound component, an organoaluminum compound is suitable;
Examples include trialkyl aluminum, dialkyl aluminum halide, alkyl aluminum sesquihalide, and alkyl aluminum dihalide, and the suitability of these differs depending on the type of titanium catalyst component. Suitable examples of the electron donor include organic compounds containing nitrogen, phosphorus, sulfur, oxygen, silicon, boron, etc., such as esters and ethers. Regarding the method for producing polypropylene using a supported catalyst component, for example, JP-A-50-108385 and JP-A-108385;
No. 50-126590, No. 51-20297, No. 51-28189,
It is described in various publications such as No. 52-151691. The propylene/ethylene random copolymer (B) to be mixed with polypropylene (A) has (i) a propylene content of 30 to 85 mol%, preferably 40 to 80 mol%, and (ii) three propylene chains. (iii) the content of boiling cyclohexane insolubles is 10% by weight or less;
Preferably it is 5% by weight or less, and more preferably it is completely absent. For example, products produced using a titanium trichloride catalyst component that is not supported on a magnesium compound usually have a large amount of insoluble matter in boiling cyclohexane, which accounts for about 20% or more, and the composition is heterogeneous, making it difficult to use polypropylene. When mixed, it is difficult to obtain a composition with stable properties, and furthermore, a composition with good gloss cannot be obtained, which is not preferable. Even if a copolymer with a low propylene content is mixed with polypropylene, the effect is not as remarkable as that in the case of blending similar rubbers that have been proposed in the past. Therefore, in order to obtain a polypropylene composition with a good balance of rigidity and impact resistance and good gloss, the propylene content should be 30 to 85 mol%,
Preferably 40 to 80 mol%, particularly preferably
It is necessary to select a copolymer with a content of 50 to 80 mol%. What is most important in the present invention is to use a copolymer with a microisotacticity of 0.8 or more, preferably 0.9 or more. Here, microisotacticity is the measurement of the fraction of three propylene chains arranged isotactically by ¹³ C nuclear magnetic resonance spectroscopy. The propylene/ethylene copolymer rubber conventionally blended with polypropylene is almost always produced using a combination catalyst of a vanadium catalyst component and an organoaluminum compound catalyst component, and the microisotacticity of such copolymer rubber is is very small, usually less than about 0.6. Even if such a copolymer rubber is blended with polypropylene, a composition with excellent strength properties cannot be obtained, and its gloss cannot be said to be good either. On the contrary, it is presumed that one of the reasons why the above-mentioned effects can be obtained by blending the copolymer used in the present invention is that the copolymer has good stereoregularity. Such propylene/ethylene copolymer rubber contains magnesium, halogen, an electron donor, preferably an aromatic carboxylic acid ester, and titanium as essential components, has a specific surface area of 100 m ² /g or more, and has a catalyst consisting of an organoaluminum compound. Alternatively, it can be produced using a catalyst further containing an electron donor, preferably an aromatic carboxylic acid ester. One way to do this is to apply for a patent application in 1977-19153.
The method described in No. 1 can be exemplified. Propylene-ethylene copolymer (B) is generally
The intrinsic viscosity measured in decalin at 135°C is from 1.0 to 15.0, preferably from 1.5 to 13.5.
Further, the melting point based on differential scanning calorimetry (DSC) is generally 130°C or less, preferably 30 to 120°C, and the Shore hardness A is 40 to 97, preferably 50 to 90. In the present invention, polyethylene
(C) may be mixed. Polyethylene is a homopolymer of ethylene or a copolymer of ethylene and other α-olefins (usually a resinous copolymer containing 85 mol% or more of ethylene), and is produced by a high-pressure method, a medium-pressure method, or a low-pressure method. It is something that Density is preferred
Those having a density of 0.90 to 0.98 g/cm ³ , particularly preferably 0.94 to 0.98 g/cm ³ . 135 again
The intrinsic viscosity measured in decalin at °C is typically 1.0
from 2.0 to 10, preferably from 2.0 to 6.0. If too large a quantity of propylene/ethylene copolymer (B) is mixed, the stiffness of the composition will be reduced, so it is generally 1 to 30 parts by weight, preferably 1 to 15 parts by weight, per 100 parts by weight of polypropylene. It is blended in the proportion of The amount of polyethylene (C) to be blended is 0 to 30 parts by weight, preferably 1 to 15 parts by weight, per 100 parts by weight of polypropylene. The composition of the present invention also includes antioxidants, ultraviolet absorbers, lubricants, nucleating agents, antistatic agents, flame retardants, pigments,
Various additives such as dyes, inorganic or organic fillers can be blended. Next, examples will be shown. Example 1 <Preparation of titanium catalyst component> 30 g of commercially available anhydrous magnesium chloride, 7.5 ml of ethyl benzoate, and methylpolysiloxane (viscosity
20C.S. (25°C)) was brought into contact for 40 hours using a vibrating ball mill in a nitrogen atmosphere. Obtained solid treated product
20 g were suspended in 200 ml of TiCl ₄ and left in contact at 80° C. for 2 hours with stirring. After the reaction was completed, the supernatant was washed with purified hexane by decantation. This operation was repeated until no chlorine was detected in the supernatant hexane. The titanium catalyst component obtained contains titanium in terms of atoms.
It contained 1.9wt% and 65wt% chlorine. By repeating the above operation several times, the following polymerization was carried out. <Polypropylene polymerization (A)> Using a continuous polymerization vessel with an internal volume of 24 cm, dehydrated hexane 3/hr and triethyl aluminum 5.9 m
mol/hr, methyl p-toluate 2.1 mmol/hr,
The titanium catalyst component synthesized above was continuously supplied in an amount of 0.11 mmol/hr in terms of titanium atoms. Continuous polymerization of propylene was carried out by continuously supplying propylene at a pressure of about 9 kg/cm ² , an average residence time of about 3 hours, and a polymerization temperature of 70°C. Furthermore, the melt index (MI) of the produced polypropylene was adjusted by supplying hydrogen. Continuous polymerization was carried out under the above conditions to obtain polypropylene (A) having the physical properties shown in Table 1 below. <Copolymerization of propylene and ethylene (B)> Using 24 continuous polymerizers, dehydrated and purified hexane 10/hr, triethyl aluminum 4 m
mol/hr, ethyl benzoate 1.33 mmol/hr, titanium catalyst component obtained above 0.045 in terms of titanium atom
mmol/hr was continuously supplied. Propylene and ethylene were continuously supplied to produce a propylene/ethylene copolymer having the composition shown in Table 1 below. Further, the pressure was about 7 Kg/cm ² , the residence time was about 1 hour, and the polymerization temperature was 60°C. In addition, MI control was performed by continuously adding _H2 . The microisotacticity of this product by ¹³ C-NMR was 0.92, and the content insoluble in boiling cyclohexane was 2.3% by weight. The Shore A hardness was 59, and the melting point measured by DSC was 40 to 70°C. Further, other physical properties of the copolymer are shown in Table 1. <Mixing of polypropylene and propylene/ethylene copolymer> The polypropylene (A) and propylene/ethylene copolymer (B) obtained above were thoroughly mixed in a Henschel mixer. This was applied to a pelletizer at a temperature of 230°C to form pellets. This item is molded into 120cm/130cm x 0.2cm by a molding machine.
A test piece with the shape was prepared and its physical properties were measured.
Initial bending modulus (FM) and gloss (Gloss) are ASTM-D-790-66 and ASTM-D-523-62T, respectively.
I followed the instructions. In addition, the falling rod strength (FD) is 0℃
In this method, a weight of a certain shape is dropped from a certain height onto a test piece placed horizontally, and the weight of the weight is changed.
Impact strength (Kg cm) determined from the energy required to break 50% of a certain number of test pieces.

[Table] Example 2 <Polymerization of a blend of polypropylene and polyethylene (A')> Using two continuous polymerizers (24 and 8) in series, polypropylene was produced in the previous polymerizer in the same manner as in Example 1. After polymerization, polyethylene was polymerized in the second stage polymerization vessel to obtain a blend of polypropylene and polyethylene (MI = 24.1, C ₂ ″ content 8.8 mol%).The MI of the obtained polymer was The amount of polyethylene polymerized was adjusted by the amount of ethylene supplied.Examples except that the blend of polypropylene and polyethylene obtained above (A') and methyl p-toluate were used instead of ethyl benzoate. Using a propylene-ethylene copolymer (B') obtained by polymerization in the same manner as in 1 (microisotacticity 0.92 boiling cyclohexane insoluble content 1.8% by weight, Shore hardness A 56, Tm by DSC 40-70°C). A blend polymer was produced in the same manner as in Example 1. The results of other physical property measurements are shown in Table 2.

[Table] Example 3 <Copolymerization of propylene and ethylene> Purified hexane 20 and triethylaluminum 4 mmol were charged into a pressurized autoclave having an internal volume of 30, and the temperature of the system was raised to 70°C. The pressure was maintained at 5 Kg/cm ² G while flowing an ethylene/propylene mixed gas (40/60 in C ₂ ″/C ₃ ″ molar ratio), and 0.4 mmol of the titanium catalyst obtained in Example 1 was added in terms of titanium atoms. , polymerization was carried out for 1 hour. After the polymerization was completed, the pressure was removed and the polymer solution was poured into a large amount of methanol to precipitate the polymer, yielding 4500 g of propylene/ethylene copolymer (B″). Analysis of this product revealed that [η] = 2・98, C ₂ ″ content = 42.5mol
It was %. The microisotacticity of this product is 0.93, and the content insoluble in boiling cyclohexane is
It was 3.6% by weight. <Polymerization of polypropylene and polyethylene blend (A″)> Polymerization was performed in the same manner as in Example 2, MI = 12.7,
A mixture of polypropylene and polyethylene (A″) with a C ₂ ″ content of 10.5 mol% was obtained. A composition was prepared in the same manner as in Example 1 using (A'') and (B'') obtained above in a ratio of 100/11.1.
When the physical properties of this composition were measured in the same manner as in Example 1, the average FM=13.9×10 ³ Kg/cm ² , FD (0
℃)=170Kg・cm, Gloss=53. Example 4 <Copolymerization of propylene and ethylene> Using 24 continuous polymerizers, dehydrated and purified hexane 10/hr, triisobutylaluminum 2m
mol/hr, 0.04 mmol/hr of the titanium catalyst obtained in Example 1 in terms of titanium atoms, and 0.15 mmol/hr of methyl p-toluate were continuously supplied. The polymerization temperature at this time was 60°C. Continuously supply propylene and ethylene (average pressure at this time is 7
Kg/cm ² G), ethylene content 37 mol%, [η]
A propylene-ethylene copolymer (B) having a composition of =3.10 was obtained. No hydrogen was used at this time. The microisotacticity of this product was 0.91, the boiling cyclohexane insoluble content was 2.3% by weight, the Shore hardness A was 56, and the Tm by DSC was 40 to 70°C. <Blend of polypropylene and polyethylene
Polymerization of (A)> Polymerization was performed in the same manner as in Example 2, MI = 6.6,
A mixture (B) of polypropylene and polyethylene with a C ₂ ″ content of 9.2 mol% was obtained.A and B obtained above were blended in the same manner as in Example 1 in a ratio of 100/11.1, and the mixture was prepared in the same manner as in Example 1. When the physical properties were measured at FD ₍₀ ℃ ₎ = 151Kg・
cm, average FM=13.0×10 ³ Kg/cm ² , and Gloss=59. Example 5 In the propylene/ethylene copolymerization of Example 4, the amount of methyl p-toluate supplied was 0.18 m
By changing the mol/hr and the supply ratio of propylene and ethylene, an ethylene-propylene copolymer with a C ₂ ″ content of 25 mol% and [η] = 2.98 was synthesized. The microisotacticity of this copolymer was 0.94, and the boiling cyclohexane insoluble matter was 2.5. This product was mixed with the polypropylene and polyethylene blend obtained in Example 4 at a ratio of 100/11.1 to produce a blend polymer, and the physical properties were measured.
FD ₍₀ °C ₎ = 134, average FM = 12.5 × 10 ³ Kg/cm ² ,
Gloss=64. Example 6 In the propylene ethylene copolymerization of Example 4, methyl p-toluate was not supplied, triisobutylaluminum was 1 mmol/hr, the titanium catalyst of Example 1 was 0.03 mmol/hr in terms of titanium atoms, and propylene and ethylene were Propylene/ethylene copolymerization was carried out in the same manner except that the supply ratio was changed and the polymerization temperature was 55°C, and [η] = 2.76, C ₂ ″ content =
A 58 mol% propylene/ethylene copolymer was obtained. The microisotacticity of this is
0.91, boiling cyclohexane insoluble content was 2.7% by weight, Shore hardness A was 87, and Tm by DSC was 97°C. This material was mixed with the polypropylene and polyethylene blend obtained in Example 4 at a ratio of 100/11.1 to produce a blend polymer, and the physical properties were measured. FD ₍₀ °C ₎ = 130 Kg cm, average FM =
It was 13.4×10 ³ Kg/cm ² and Gloss=50%. Comparative Example 1 Using a pressurized autoclave similar to that used in Example 3, hexane 20, Al(C ₂ H ₅ ) ₂ Cl 15m
mol, TiCl ₃ AA (manufactured by Toho Titanium Co., Ltd.: trade name
Added 15 mmol of TA (-131) in terms of Ti atoms and heated to 60°C.
The temperature rose to . Polymerization was carried out for 12 hours while maintaining the pressure at 5 kg/cm ² G while circulating an ethylene-propylene mixed gas (C ₂ ″/C ₃ ″ molar ratio: 40/60) and hydrogen. After the polymerization was completed, the resulting polymer solution was poured into a large amount of methanol to precipitate the polymer, yielding 2200 g of propylene-ethylene copolymer. When I analyzed this, I found that [η]=
2.7, _C2 ″ content = 52mol%, boiling cyclohexane insoluble content 23% by weight, microisotacticity
It was 0.90. The propylene-ethylene copolymer obtained above was mixed with the polypropylene _and polyethylene blend obtained in Example 3 at a ratio of 100/11.1 to produce a blend and its physical properties were measured _.
=110Kg・cm, Average FM=13.6×10 ³ Kg/cm ² , Gloss
It was =36. Comparative Example 2 Using a pressurized continuous polymerization device with an internal volume of 24,
Dehydrated purified hexane 6/hr, VOCl ₃ 1.4 mmol/hr
and ethylene aluminum sesquichloride 11.2
While continuously supplying mmol/hr, propylene, ethylene and hydrogen were continuously supplied to produce an ethylene-propylene copolymer. The average residence time of the catalyst during copolymerization is about 1.6 hours,
The pressure of the copolymerization reactor is 5.2Kg/ ^cm2 , and the ethylene/propylene molar ratio in the gas phase is 1/3.3.
It was hot. As a result of the copolymerization, ethylene/propylene copolymer was obtained at a rate of 250 g/hr. The resulting ethylene-propylene copolymer had an intrinsic viscosity [η] of 2.54, a _C2 content of 58 mol%, a microisotacticity of 0.43, and a boiling cyclohexane insoluble content of 0% by weight. Ta. The ethylene-propylene copolymer obtained above was mixed with the blend of polypropylene and polyethylene obtained in Example 4 at a ratio of 100/11.1 under the same conditions as in Example 1 to prepare a polypropylene composition. The physical properties of the obtained polypropylene composition were measured in the same manner as in Example 1.
FD ₍₀ ℃ ₎ = 150Kg・cm, average FM = 13.5×10 ³ Kg/
cm ² , Gross=36.

Claims (1)

[Scope of Claims] 1 (A) Based on 100 parts by weight of polypropylene, (B) (i) propylene content of 30 to 85 mol%, (ii) microisotacticity of 3 propylene chains of 0.8 or more, (iii) 1 to 30 parts by weight of a propylene/ethylene random copolymer obtained by polymerization in the absence of the above polypropylene (A), with an insoluble content of boiling cyclohexane of 10% by weight or less, and (C) 0 parts by weight of polyethylene 30 parts by weight of a polypropylene composition. 2 The intrinsic viscosity of the propylene/ethylene random copolymer measured in decalin at 135°C is
Claim 1 using 1.0 to 15.0
Method described.