JPS587406A - Preparation of propylene polymer - Google Patents

Abstract

PURPOSE:To prepare the titled polymer having high processability and free of fish-eye, by the two-step polymerization comprising the preparation of a polymer having a specific intrinsic viscosity using a catalyst system composed of a Ti- containing component and an organic A1 compound, and the preparation of a polymer having high intrinsic viscosity. CONSTITUTION:The objective (co)polymer having an intrinsic viscosity[n]of 4-6dl/g is obtained by the polymerization of propylene or the copolymerization of propylene and an alpha-olefin using a catalyst system composed mainly a titanium-containing solid catalyst component and an organic aluminum compound, wherein said polymerization is carried out in two steps comprising the first step to prepare a (co)polymer having an intrinsic viscosity[n]of 0.6-3.5dl/g in an amount of 30-70wt%, and the second step to prepare a (co)polymer having an intrinsic viscosity[n]of 5-10dl/g and >=2.5 times that of the first-step polymer in an amount of 30-70wt%.

Description

[Detailed description of the invention] The present invention relates to a method for producing propylene polymers.

More specifically, while maintaining the excellent rigidity, impact resistance, transparency, and heat resistance of the crystalline propylene polymer, it has excellent moldability, especially in blow molding and extrusion molding. The present invention also relates to a method for producing a propylene polymer that eliminates the problems of fish eyes and surface roughness.

Because of its favorable properties, propylene polymers are used in a wide variety of applications, including blow molded products such as detergent containers and extrusion molded products such as films and sheets. Rigidity and impact resistance, which are two of the desirable properties of propylene polymers, generally depend largely on the average molecular weight if the stereoregularity, which influences cough properties, is almost the same, and as the average molecular weight increases, the impact resistance conversely, lowering the average molecular weight increases crystallinity and improves rigidity. Therefore, if the average molecular weight is increased in order to emphasize impact resistance, the moldability deteriorates extremely, and especially in blow molding and extrusion molding, the melt viscosity increases, causing molding problems.
III: Significant skin irritation occurs. The occurrence of rough skin can be avoided by increasing the molding temperature, but with this method, the drop in melt viscosity causes sagging due to the parison's own weight in blow molding, and bubbles in normal air-cooled blown film molding. Undesirable and dangerous effects such as a wobbling phenomenon and a large number of wrinkles in the formed film appear, and this is not an essential solution. In propylene polymers with improved impact resistance and, therefore, average molecular weight, improvement in moldability is particularly desired.

Generally, in order to improve moldability from the polymer side, the following points are important. In other words, skin roughness is controlled by the melt viscosity in the high shear rate range, while the sagging of Parin due to its own weight and the bubble shaking phenomenon are controlled by the melt viscosity in the low shear rate range. In addition, in order to prevent the parison from sagging due to its own weight and from bubble swaying, it is necessary to make the viscosity behavior of the polymer more pronounced in the high shear rate region.

For the purpose of improving the molding processability of propylene polymers, methods have been proposed in the past in which polymers of various types having a molecular weight of 4 are polymerized in multiple stages and methods in which they are mixed. For example, in JP-A No. 3131 and JP-A No. 3131 and JP-A No. 3131, the content of high molecular weight propylene polymer is set to 0. Oj-/
! A multi-stage polymerization method using a weight ratio of 3 to 30% by weight is
Special public Akira! TO-4'14 number, Tokukai Showa 3 Tei-7sha 41
In No. 1 and No. 5J-9/9k1, the amount of high molecular weight propylene polymer mixed was 60 to 99. ! Weight -160~
De! A mixing method with a weight of 2 to 30 weight has been proposed. However, according to studies by the present inventors, these methods improve moldability to some extent but are not sufficient, or even if moldability is not sufficiently improved, fish eyes often occur in the cast object. It was a turtle that was spinning.

Inventor et al.Molding processability is improved and fish-free
With the aim of producing a nine-propylene polymer that eliminates the problems of eye and surface roughness, we are conducting intensive studies to realize the inherent advantages of crystalline propylene polymer by using certain specific polymerization conditions. We have found that the above objects can be achieved while maintaining the rigidity, impact resistance, transparency, and heat resistance of the VC11 of the present invention.

The gist of the present invention is that a titanium-containing solid catalyst component and an organic alkali
In a method for producing a propylene homopolymer or a propylene-d-olefin copolymer by polymerizing propylene or propylene and an α-olefin using a catalyst system mainly consisting of a
[ma] is 0.4 dt/l or J,! dLt/f of a propylene homopolymer or propylene-a-olefin copolymer of 30 to 70 weight;
producing a propylene homopolymer or a propylene-α-olefin copolymer in which t/ is as follows, and [η] is at least j times as large as the former, exceeding 30% by weight and not exceeding 70% by weight; The process is carried out in two steps to determine the intrinsic viscosity of the entire polymer.
The present invention relates to a method for producing a propylene homoheavy metal body or a propylene--olefin copolymer, characterized in that the polypropylene monoheavy metal or the propylene--olefin copolymer is made to have a dt of more than -dt and less than 4dt7.

In further detailing the present invention, the catalyst system used in the present invention includes a titanium-containing catalyst component and an organic aluminum compound.

The titanium-containing solid catalyst component is a known carrier-supported catalyst component obtained by contacting a solid magnesium compound, titanium tetrahalide, and an electron-donating compound, titanium trichloride, or a known catalyst containing titanium trichloride as a main component. You can choose from the ingredients. Also catalyst/ltk'ripoly-r-toK
In a highly active catalyst system that can obtain more than g! This is particularly preferred since the step of removing one component can be omitted.

The cocatalyst organic Al 1=ium compound has the general formula MutRnX
1-H (wherein, and represent a hydrocarbon bulk group having 1 to 00 carbon atoms, X represents a halogen, and n represents the number of J≧n>l and j). When the titanium-containing solid catalyst component is a carrier-supported catalyst component containing a solid magnesium compound, it is preferable to use hot metals such as MutR,i or AtR, and MutR,X, while titanium trichloride or When the catalyst component contains titanium trichloride as a main component, it is preferable to use MutR.

The ratio of each catalyst component used is usually 1:1 to 10 in the molar ratio of Ti SM LRnX@-H in the titanium-containing homogeneous catalyst component.
0, preferably l: selected from the range of C.

Furthermore, in the method of the present invention, known electron-donating compounds may be used as the K1.7 component of the catalyst and cocatalyst components. When using a third component, typically
T1 in the titanium-containing isocatalyst component: molar ratio of the third component is 7,0.0/~IO1 preferably/: 0.0j
? Selected from the range -1.

In the method of the present invention, polymerization is carried out in one step using the catalyst system as described above, and it is determined which step is carried out first, the step of obtaining a low molecular weight polymer or the step of obtaining a high molecular weight O polymer. It's okay.

The polymerization method may be carried out batchwise, or may be carried out continuously using a co-group or higher reaction tank.
The polymerization may be carried out in an inert hydrocarbon diluent such as butane, hexane or heptane or in liquefied propylene, or may be carried out by so-called gas phase polymerization. Polymerization temperature is usually 410~
/DO°C, preferably from the range of 50 to t0°C. α-olefins copolymerized with propylene include ethylene, butene-11hexene/, l-methylpentene-1
Hydrogen, dialkylzinc, etc. are used to adjust the molecular weight selected from 1-octene-1, etc., and hydrogen is preferred.

To explain the step of obtaining a low molecular weight polymer, the intrinsic viscosity [η], which represents the size of the molecular weight, is 0.461/f. ! dt/f, preferably 1iO0? a
1 polymerization 1 ml so that A/l to j az7'y
i and the amount of hydrogen as a molecular weight regulator. Usually, the hydrogen concentration in the gas phase (9 for propylene is propylene and α
- the ratio of hydrogen to the sum of olefins) is o, r ~ 30
It's a mole rumor. This amount is also good. In this case, the content of α-olefin in the copolymer is 0. Stereoregularity of the polymer is determined under Fiiolt-PJ (hereinafter sometimes abbreviated as Process I).
is to- or higher, preferably 91 or higher. Note that the intrinsic viscosity [η] (1-/7) (hereinafter sometimes abbreviated as [η]) is defined in a tetralin solution at /3°C. is the amount remaining after extraction with boiling lIn-butane for 6 hours using a modified JL Soxhlet extractor. In addition, the amount of the low molecular weight polymer is 30 to 70 weight of the total polymer production amount, preferably 31-A
! Select the polymerization time so that r weight remains constant.

Next, to explain the step of obtaining a high molecular weight polymer, the intrinsic viscosity [η] exceeds z tst/f -/o d
t/f or less, preferably s, z dt7y to td t/
The polymerization temperature and the amount of hydrogen as a molecular weight regulator are selected so that f is 0. Usually, the hydrogen concentration in the gas phase is 0 to a molar. If [da] is less than z it/, the effect of improving non-Newtonian viscosity behavior will be small and undesirable;
] exceeds 10 at/f, which is undesirable as fish-eye formation occurs in the molded product obtained from the final polymer.The high molecular weight polymer may of course be propylene homopolymer, but
From the viewpoint of physical properties such as impact resistance, a random copolymer of propylene and α-olefin is more preferable. In this case, the content of α-olefin in the copolymer is 70% by weight.
The following shall apply.

The stereoregularity of the polymer is greater than or equal to xFito, preferably greater than or equal to 0. The amount of the high molecular weight polymer is more than 30% by weight and less than 70% by weight of the total polymer production, preferably J
If the amount of the high molecular weight polymer is less than 30% by weight, the non-Newtonian viscosity behavior will not be sufficiently improved, and therefore the effect of improving moldability will be small and unsatisfactory. If the desired results cannot be obtained, or if the product exhibits significant non-Newtonian viscous behavior, the molded product may have fish.
The appearance of eyelids is not desirable. Moreover, if the weight exceeds 70 weight, the effect of molding processability on a 41 to 10 weight plate will not be sufficient and satisfactory results will not be obtained.

The ratio of [eta] of the high molecular weight polymer to [eta] of the low molecular weight polymer is 0.01 or more, preferably 3 or more.

If this ratio is less than 2.1, the effect of improving non-Newtonian viscosity behavior is not sufficient, and therefore the effect of modifying moldability is not sufficient.

The intrinsic viscosity of all produced polymers exceeds tlt/f4
tlt/f or less.

Note that a small amount of component J having a different molecular weight may be mixed in by polymerization as long as the purpose of the present invention is not impaired.

Hereinafter, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples as long as the gist of the invention is expressed. In addition, in the examples, the evaluation method of various physical properties of the polymer was the following per second test.

Outflow ratio: Melt by Mu8TM DI231-TSO
Using a flow index measuring device, the extrusion amount at shearing stress t
The ratio of the extrusion amount at o4 dyne/ai was determined.

The larger the outflow ratio, the more pronounced the non-two Newton viscosity behavior becomes.
(b) It exhibits favorable properties such as a high melt viscosity in the low shear rate region and a lower melt viscosity in the high shear rate region.

Melt-workability: Using a screw set extruder, outer diameter / 2
, Om, inner diameter/l), from a circular die of OWm
The changes in the falling speed of parisons extruded at 0°C were measured and ranked as follows.

Rough skin, fish eyes; using a screw set extruder, outer diameter / 7, 01+11s inner diameter 10. The rough skin (so-called shark skin) and fish eyes on the surface of the 9 barinone extruded using the OMl annular die are observed, and the 9 is ranked as follows.

Molding stability: using a screw set extruder, outer diameter 30.0
WILs is extruded using a spiral round ring die with an inner diameter of 1.0 mm at 0°C, and is made thick using the air-cooled inflation method! A tubular film of μ was formed, and the stability of the bubbles was observed and ranked as follows.

7th Yield Point Strength: This is a value measured at 0°C by a tensile test of a dumbbell piece punched out from a press sheet, in accordance with M8TM D4Jt-'1.

Izot impact strength: Measured on a short piece punched from a press sheet with a notch in accordance with STM v2sbK.

Tensile impact strength: Measured on a dumbbell piece punched from a press sheet in accordance with A197M D-/122K. These are all measured values at 0°C.

The ratio of the polymers in the first stage and the second stage was determined by a fluorescent X-ray method and was calculated based on the content of the catalyst (T1) in the 91st stage and the total produced polymer.

The ethylene content in the polymer was determined by conventional methods using infrared absorption spectroscopy.

Catalyst Production Example 1 (4) Production of solid titanium trichloride catalyst component
, Ot, and titanium tetrachloride J, 0 mol were charged, and further 7 mol of di-n-octyl ether co was added. While stirring and maintaining 2z"c and 11C, add 1.0 mol of diethyl aluminum monochloride fn-hexane θjt
When the solution was gradually added dropwise, a homogeneous solution of titanium trichloride in n-hexane was obtained. Then, when the homogeneous solution of titanium trichloride was heated to 9j@CK, a purple precipitate of titanium trichloride was observed to form during the heating. After stirring for several hours at VZ℃, the precipitate was separated,
After repeated washing with n-hexane, a finely granular purple solid titanium trichloride catalyst component was obtained. Elemental analysis of this product revealed the formula 1 (%) Pretreatment with propylene Capacity coat 5 autoclave fully purged with nitrogen Ig
- Add 3 t of n-hexane and add di-n-propylaminium monochloride/, 4 mol, while stirring (4) above.
The solid titanium trichloride catalyst component obtained in
Then, the internal temperature was adjusted to 30°C, and propylene gas O injection was started under stirring, and propylene gas O injection was continued at the same temperature until the polymerized propylene reached /2!10 f. Ta. The solid was then separated and washed with n-hexane repeatedly to obtain a titanium trichloride catalyst component containing polyp-a-pyrene.

Example 1 Capacity! Liquefied propylene 3.31.
hydrogen, di-n-propylaluminum monochloride J,
j vn wxo]j and phenyl acetate 0.01 m
Catalyst production example 1 after raising the temperature to 6J℃ after charging mob・
The first stage polymerization was started by adding a small amount of ethylene to the titanium trichloride catalyst component obtained in step (9) so that the amount was 63 da.During the polymerization, the hydrogen concentration in the gas phase (
The ratio of hydrogen to boupyrene) is 0. Kowxo1ef
i K-, the ethylene concentration in the gas phase (ratio of ethylene to propylene) was maintained at θ, tmol·-K. 3
．． After 0 hours, the OII-formed pyrene phase in the autoclave was pumped to complete the 7th stage polymerization, and the catalyst (1) content and the content of the polymer discharged in the 1st stage were measured. After sampling a small amount of polymer, a friend was charged with a small amount of liquefied propylene, hydrogen, and hydrogen, and the autoclave was adjusted to 70"CK to start the polymerization of stage 1.During the polymerization, the polymerization in the gas phase The hydrogen concentration is maintained at //, Ovrole-9. After /, j hours, the liquefied propylene phase in the autoclave is purged to complete the polymerization of the second stage, and the entire produced polymer powder is removed.
I got 6 tons.

To the thus obtained polymer powder, 0.0% of %Biite(co,6-di-t-butyl-P-cresonyl) was added. / Cooking Irganox toto (Geigy Company stabilizer, trademark) 0. /*
, silacryl thiodipropionate to 0, co-1, calcium stearate to 0. Added flathead, including 11 da OwxO
The animals were pelletized using a single-screw extruder, and various physical properties were measured after death.

The results are shown in Table 9. The outflow ratio is large, so the non-Newtonian viscosity behavior is ＠, and the melting sagging property of the parison is
Evaluations of rough skin and fish eyes were also good, and even in air-cooled blown film molding, the bubble shaking phenomenon was hardly noticeable and the molding stability was good. Furthermore, the balance between the first yield point strength, the Izot impact strength and the tensile impact strength was also good.

Comparative Examples 1 to 3 In Example 1, only the first stage of polymerization was performed. However, by changing the hydrogen concentration, ethylene concentration, polymerization temperature, and polymerization time in the gas phase as shown in Table 7, in Comparative Examples 1 and 2, propylene and a small amount of ethylene were copolymerized, and in Comparative Example J, Homopolymerization of propylene was carried out.

The results are shown in Table 1. Although the fish-eye evaluation of the parison in all comparative examples was good, noticeable roughness occurred on the surface of the parison, and AT-forming was not possible in air-cooled blown film molding. 9. The stability of the window molding is poor, with severe shaking phenomenon observed.

Example 6 Repeat Example 1. However, the hydrogen concentration in the gas phase,
The ethylene concentration, polymerization temperature, and polymerization time were changed as shown in the table.

The results are shown in Table 2, and in all Examples, the outflow ratio was large, so the non-Newtonian viscosity behavior was remarkable, and the surface roughness of the parison was rough, and the melt sagging property and air-cooled blown film were rough. A polymer with excellent molding stability and excellent molding processability was obtained. Also, the balance of the first yield point strength, isot impact strength and tensile impact strength is comparable to that of Comparative Example/-JK.

JP-A-58-7406 (7) Comparative Example Tei~lO Example 1 was repeated. However, hydrogen dark red in the gas phase,
The ethylene concentration, degree of polymerization, and polymerization time were changed as shown in Table 3.

The results are shown in Table 7.

Comparative example shows intrinsic viscosity change [η] of high molecular weight polymer (first stage)
was large, the flow rate ratio was large, and the non-Newtonian viscosity behavior was large, but the fish eyes and skin roughness of Varynon were poor (l), and the forming stability during film forming was also poor. Furthermore, the tensile impact strength and Izot impact strength were also poor.

Comparative Example &S & is a high molecular weight polymer (Comparative Example I is the 7th row,
Comparative Example 6 is a case in which the ratio of the first stage) is significantly different. There were no fish a or i in the parison, which was good.
The outflow ratio was not sufficiently large, and the surface roughness of the parison and the molding stability during film molding were also insufficient.

A comparative example is a case where the high molecular weight polymer (second stage) has a low intrinsic viscosity. The flow rate ratio, roughness of the nokurison, melt sagging properties, and molding stability during film molding were insufficient.

Comparative Examples t and y are cases where the amount of high molecular weight polymer (Comparative Example G is the first stage, Comparative Example D is the first stage) is small. Comparative Example t had a large flow rate ratio, that is, the non-Newtonian viscosity behavior was remarkable, and was good, and the surface roughness of the parison, molten S drooping property, and molding stability during film forming were also good. A large number of fish eyes occurred, which damaged the commercial value of the molded product. The comparative example had sufficient graininess in terms of outflow ratio, roughness of the parison, and molding stability.

Comparative Example 10 is a high molecular weight polymer (first stage) and a low molecular weight polymer (
This is a case where the ratio of the intrinsic viscosity [η] of the first stage) is small. It was unsatisfactory in terms of outflow ratio, roughness of the balisone, and molding stability.

As explained in detail above, according to the method of the present invention using certain specific polymerization conditions, a propylene polymer can be obtained in which the molding processability is improved in a well-balanced manner and the problem of the occurrence of roughness in the fixation eyes is eliminated. .

Claims (1)

[Claims] (1) In a method for producing a copolymer of propylene or propylene and α-olefin using a catalyst system mainly consisting of a titanium-containing solid catalyst and an organic aluminum compound, the polymerization is carried out by adjusting the intrinsic viscosity [da] But 0.4 d4/F
to J, I At/f of producing a propylene homopolymer or a propylene-α-olefin copolymer of 30 weight or more and less than 70 weight, and the intrinsic viscosity [calyx]!
Purpylene homopolymer or poubilene-niolef 47 copolymer exceeding 30% by weight and 70% by weight or more than 6L/f and 106 to 7 or less, and [Ma] is 3 times or more of the former. - Performed in a co-stage with the following manufacturing stage, and the intrinsic viscosity of the entire polymer exceeds at7y.
A method for producing a propylene homopolymer or a propylene-i-olefin copolymer, characterized in that the t/f or less