JPS59149907A - Crystalline polypropylene and its production - Google Patents

Abstract

PURPOSE:To produce crystalline PP having high melt tension and rigidity and good moldability, by using a stereoregular polymerization catalyst and effecting the polymerization in two stages in each of which the produced PP has a limiting viscosity in a specified range. CONSTITUTION:Crystalline PP having a limiting viscosity of 2-6dl/g, a melt index of 0.01-5g/10min, and an isotactic pentad fraction of 0.940 or above is produced by using a stereoregular polymerization catalyst (e.g., a diethylaluminum chloride/titanium trichloride mixture), to produce 50-85wt%, based on the total polymer formed, PP of a limiting viscosity of 0.5-3.0dl/g in the first stage and produce 50-15wt%, based on the total polymer formed, PP of a limiting viscosity of 9dl/g or above in the second stage. While conventional PP is difficult to process by blow forming, sheet molding, etc. because of its low melt tension, the crystalline PP having the above properties obtained by the process of this invention can be processed by the above-mentioned molding methods because it has high melting tension and rigidity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a crystalline polypropylene and a method for producing the same, and more particularly to a crystalline polypropylene having high melt tension, high rigidity, and good moldability, and a method for producing the same.

Although crystalline bo4nopropylene has poor properties such as rigidity, heat resistance, and surface gloss, it has been difficult to perform blow molding, sheet molding, etc. due to its low melt tension. Generally, increasing the molecular weight of polypropylene increases the melt tension, but in this case there is a problem in that the rigidity and moldability are significantly reduced. Therefore, in order to solve this drawback, a method of blending low density polyethylene has been proposed (Japanese Patent Publication No. 47-80614, Japanese Patent Application Laid-Open No. 50-884 '8). However, this method has the drawback that uniform dispersion is difficult and the characteristics of crystalline polypropylene, such as rigidity and heat resistance, are significantly reduced. In addition, in order to widen the molecular weight distribution, multi-stage polymerization methods (JP-A-54-58389, JP-A-54-14444)
No. 8) has also been proposed, but the resulting polypropylene does not have sufficiently satisfactory melt tension and moldability.

Therefore, the present inventors have worked diligently to develop crystalline polypropylene that has excellent melt tension, moldability, rigidity, etc. without the drawbacks of the above-mentioned conventional techniques, and as a result, they have completed the present invention.

In other words, the intrinsic viscosity of unexplored and bright materials is 2 to 6 dt/f.
.

Meltoy〉Decks (M engineering) is o, cN ~ 55'/1o
minute and isotactic pentad fraction is 0.940
The above-mentioned crystalline polypropylene (first invention) is a method for producing polypropylene by two-step polymerization using a stereoregular catalyst, in which polypropylene with an intrinsic viscosity of α5 to xoaz7'y is produced in the first step. 50 to 85% by weight of the total polymerization amount is produced, and in the second stage, 4? 5 of the total polymerized amount of lippropylene
It has an intrinsic viscosity of 2 to 6 at/i, characterized by being produced in an amount of 0 to 15% by weight.

This is a method (second invention) for producing a crystalline polypropylene which has an M ratio of 0.01 to 55'/Io and an isotactic pentad fraction of 0940 or more.

The crystalline q IJ Probile according to the first invention has an intrinsic viscosity of 2 to 6 dL/ff, preferably 5 to 5 dt/f.

If the intrinsic viscosity is less than 2 dt/P, the melt tension will be lowered, and if it exceeds 6 dt/ff, the moldability will be lowered, which is not preferable. Also, M work is 0.01~57/
10 minutes, especially [105 to 2 jil-/10 minutes is preferred. If the M value is less than 0.01 p/10 minutes, the moldability will decrease, and if it exceeds SP/10 minutes, the drawdown will increase. Furthermore, the crystalline pyripropylene has an isotactic base fraction of α940 or more, preferably 0.
．． 945 to 0.985. If the isotactic pentad fraction is less than α940, the rigidity decreases, which is not preferable. Here, the isotactic pentad fraction is defined by A, Macromole et al.
This is the isotactic fraction in pentad units in the molecular chain of Zaripropylene measured by the method published in J. C. Cules, 6.925 (1'975), that is, the method using 130-NMR. In other words, the isotactic fraction is the fraction of one propylene monomer unit at the center of a chain in which five consecutive meso-bonded hapropylene monomer units are formed. However, regarding peak assignment, Macromolecules, 8.687 (
This is done based on the correction method of the above-mentioned document described in 1975). Specifically, the isotactic pentad unit is measured as the intensity fraction of the mmmm peak among the total absorption peaks in the methyl carbon region of the c13-NMR spectrum.

The value of the pentad fraction in the present invention is the value of the obtained crystalline polymer as it is, and is not the value of the polymer after extraction, fractionation, etc. The crystalline polypropylene of the first invention has the above-mentioned physical properties, or is further subjected to gel permeation chromatography (
Gpa method) Weight average molecule Hkl number average by K (M
From the viewpoint of moldability, it is preferable that the ratio of W/Mn is 10 or more, and the size is 15 to 50. If it is less than 10, moldability will decrease.

The crystalline propylene of the present invention has high melt tension, high rigidity, and excellent moldability.

The method of the second invention is an efficient method for producing crystalline IJ-problem having the above-mentioned physical properties.

This second invention is a method for producing polypropylene by two-step polymerization using a stereoregular catalyst.

The stereoregular catalyst used here is ethylene.

The catalyst is a catalyst commonly used for stereoregular polymerization reactions such as Probile, and usually a mixture of a transition metal halide component and an organoaluminum compound component is used. As the transition metal halide compound, a titanium halide is preferred, and titanium trichloride is particularly preferred. Titanium trichloride is obtained by reducing titanium tetrachloride by various methods, which are further activated by ball milling and/or solvent washing (for example, washing with an inert solvent and/or an inert solvent containing a polar compound). Titanium trichloride or titanium trichloride eutectic (e.g. TiC4/τAtO4) is further co-pulverized with amines, ethers, esters, sulfur, halogen derivatives, organic or inorganic nitrogen or phosphorus compounds, etc. be able to. Furthermore, a material in which a titanium halide is supported on magnesium lam can be used. As an organoaluminum compound, the general formula AZ
RnXs -21 (R is a C7-c, o alkyl group.

Compounds represented by X Jd halogen, where n is O (n≦3) are suitable, such as dimethylaluminum chloride, diethylaluminum chloride, and ethylaluminum sesquichloride.

Examples include ethylaluminum dichloride and triethylaluminum, and these can also be used in mixtures.

These catalyst components are usually mixed in a ratio of 1 to 100 moles of the organoaluminum compound per 1 mole of the metal compound. The above-mentioned standing tree regular catalyst is commonly used fjt
and combinations etc. are used at each stage.

The first stage of polymerization of propylene in the method of the second invention is carried out at a temperature of 40 to 90°C, preferably 50 to 80°C, and a pressure of 1
~50 kg/crd% Preferably 1~15 kg/
c++! The intrinsic viscosity is α5 to 50 dt.
/Li-1 preferably 1.0 to 2. s dt/P polypropylene is produced in an amount of 50 to 85% by weight, preferably 55 to 86% by weight of the total polymerization amount. If the intrinsic viscosity of the polypropylene resin is less than (L 5 eLt/f), the impact strength of the resulting crystalline polypropylene decreases, and if it exceeds 50 degrees, the rigidity decreases, which is not preferable.

In carrying out the second stage polymerization, the temperature and pressure conditions were the same as those in the first stage, and the intrinsic viscosity was 9 d.
t, Q (J, above, preferably 10 to 15 u/p polypropylene) is produced in an amount of 50 to 15% by weight, preferably 45 to 17% by weight of the total polymerization amount. The limit of the polypropylene obtained in the second stage When the viscosity is less than 9 dt/f, the melt tension of the crystalline polypropylene obtained decreases.

In addition, if the polymerization amount exceeds 50% by weight, the resulting crystalline propylene + 7) stiffness and moldability will decrease, resulting in 15% by weight and 7% by weight.
If it is less than that, the melt tension will decrease.

In the method of the present invention, the limiting viscosity [η] can be adjusted using a molecular weight regulator (
This can be done by appropriately changing the concentration of H2, etc.).

The method of the present invention is applicable to various polymerization methods, such as a continuous method using two or more polymerization tanks, a batch method using one or more polymerization tanks, and furthermore, these continuous methods and batch methods. A combination of methods can be applied. (Also, each step of the reaction may be carried out in two or more polymerization tanks. In this case, it is sufficient that the average intrinsic viscosity (?) of the products in each tank is within a predetermined range.

There are no particular restrictions on the polymerization method, and suspension polymerization is used.

Solution polymerization, gas phase polymerization, etc. can be employed.

In addition, examples of inert solvents used in suspension polymerization include aliphatic hydrocarbons such as hexane and heptane; alicyclic hydrocarbons such as cyclohexane; and aromatic hydrocarbons such as Hensen and toluene. .

By the manufacturing method as described above, the crystalline foam IJ' of the first invention is produced.
7'Robilet> can be efficiently produced.

The crystalline polypropylene of the present invention has high melt tension, high rigidity, and excellent moldability, so it is extremely useful as a material for home appliances, automobile parts, etc.

Next, the present invention will be explained in detail using examples.

Examples 1-3 Dehydrated n-hebuta>21 was charged into an autoclave with an internal volume of 5 tons and equipped with a stirrer, and diethylaluminum chloride 2.
51 and 0.209 of titanium trichloride were added.

In the first stage polymerization reaction, the liquidus temperature was maintained at 60 °C,
Produced y +) Hydrogen measured so that the propylene has a predetermined intrinsic viscosity [η] and the reaction pressure is 6 to 9/c
Propylene was continuously supplied so that the amount of the polymer was d, and polymerization was carried out with stirring for 120 minutes.

Then, remove unreacted gas and lower the liquidus temperature to 5.
The temperature was lowered to 0°C.

Next, the second stage polymerization reaction is carried out at a temperature of 50°C and a pressure of qk.
Continuously supply hydrogen and proviso〉 measured to reach a predetermined ultimate viscosity kcη〕 while maintaining 60
Polymerization was carried out with stirring for minutes.

After the polymerization is completed, unreacted gas is removed and the polymerization product ′
5 Qm/n-butanol was added to the mixture, and the mixture was stirred at 80°C for 1 hour to perform catalytic decomposition. Thereafter, the polypropylene was separated, washed and dried to obtain a white powdery polymer. Table 1 shows the physical properties measured for the obtained polymer.

Comparative Reli 1 and 2 The same operations as in the actual IAL examples were carried out except that the Ner limiting viscosity of the polymer produced at each stage and the amount of polymerization were varied. The results are shown in Table 1.

Comparative Example 6 The same operation as in Example was performed except that the second stage was not performed. The results are shown in Table 1.

/ Shin 1... Measured value in 165°Cl decalin Keyaki 2.
-・Compliant with J Engineering S K675B 3... ASTM
Compliant with D747・4...Using Toyo Seiki melt tension tester, orifice D・=2.10 m/n'L,
L = 8.00772/tn, temperature 250°C
1 plunger 1 descending speed 1 ton/min, thread d 1 take-up speed 2
Constant value pumping under the conditions of Or, p, m... Based on ASTM D 1705, using Shimadzu flow tester, orifice D = 0.76 m/
m.

Measured value under the conditions of L = 25 m/nt, temperature 260°C, shear rate 546 sec. Patent applicant: Idemitsu Petrochemical Co., Ltd.

Claims (1)

[Claims] (11' h, crystalline polypropylene having a limiting viscosity U of 2 to 6 P/9, a melt index of 001 to 5 P/10 min, and an isotactic pentad fraction of 0940 or more). 2) Crystalline polypropylene> is a weight average molecule, 1f
Bamboo shoot Ef with a ratio of iZ number average molecule or more of 10 or more
j. The crystalline polypropylene according to item 1. (3) In a method for producing polypropylene by two-stage polymerization using a stereoregular catalyst, polypropylene with an intrinsic viscosity of 05 to AOd4/7 is produced in the first stage of the chain in an amount of 50 to 85% by weight of the total polymerization set. In the second stage, 4i
It is characterized by producing polypropylene having a limiting viscosity of 9 d4/7- or more in an amount of 50 to 15% by weight of the total polymerization amount, a polar viscosity of 2 to 6 dJ7ff, and a melt index of 0.
01-51/10 minutes and isotactic polypropylene A method for producing crystalline polypropylene having a tad fraction of 0940 or more.