JPS58120610A - Preparation of polypropylene having improved transparency - Google Patents

Abstract

PURPOSE:To prepare the titled polymer having high bulk density and excellent transparency, and useful for a food container, etc., in high yield, by the continuous two-stage polymerization of propylene under specific conditions using a catalyst composed of a Ti compound such as titanium trichloride and an organic Al compound. CONSTITUTION:The objective polymer is prepared by the continuous polymerization of propylene using a catalyst composed of (A) a catalyst component containing a titanium compound selected from titanium trichloride, a titanium trichloride composition and a titanium compound supported by or chemically bonded to a carrier, and (B) an organic aluminum compound (e.g. diethylaluminum chloride). The polymerization is carried out in two steps comprising the first step polymerization wherein 5-35wt% of the total polymerizing amount is polymerized at <=65 deg.C and the second step polymerization at 70-90 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for providing a propylene polymer having a good bulk specific gravity of powder and a good yield.

More specifically, the polymer obtained by practicing the present invention is a propylene polymer particularly suitable for film or blow grade for food containers.

Conventionally, blow-grade polypropylene for films or food containers has been produced by homopolymerizing propylene, but this method has the drawback of insufficient transparency.

Furthermore, in order to improve the yield of the product and the catalyst activity, techniques disclosed in JP-A-54-141894 and JP-A-54-142291 have been proposed.

The former method involves contacting titanium trichloride with an organoaluminum compound in an inert organic solvent, then prepolymerizing propylene or hapropylene with another d-olefin, and then polymerizing propylene or propylene with another d-olefin. It is a polymerization method characterized by carrying out polymerization, and the latter is characterized by carrying out main polymerization after prepolymerizing propylene or propylene and an olefin at a higher temperature than in the prepolymerization after the above prepolymerization. This is a polymerization method. According to these polymerization methods, it is true that the product yield,
Although both catalytic activity is improved, the polymerization temperature in the main polymerization cannot be increased because the ratio of the amount of pre-electrification or the amount of pre-polymerization to the total amount of polymerization is small, and a propylene polymer with sufficiently excellent transparency is produced. It is impossible to do so.

The present invention further improves transparency and greatly increases product yield, and exhibits various useful effects as a blow grade for films and food containers. The present invention will be explained in detail below.

The present invention comprises a catalyst component having titanium as an active ingredient, either a (N titanium trichloride or a titanium trichloride composition, or a carrier catalyst component supported or chemically bonded with a Bl titanium compound), and (C) an organoaluminum compound. When propylene is continuously polymerized using a catalyst consisting of
As the polymerization step, 5 to 35% by weight of the total polymerization amount is carried out at a temperature of 65°C or lower, and then propylene is polymerized at a temperature of 70 to 90°C, yielding polypropylene with excellent transparency. This is a good way to get it.

The method of the present invention is divided into a first stage polymerization and a second stage polymerization, both of which have the common point of polymerizing a homopolymer of propylene. However, in the first stage polymerization, a highly crystalline homopolymer of propylene is polymerized at a relatively low temperature of 65° C. or lower in an amount ranging from 5 to 35% by weight of the total polymerization amount. By providing this stage, it is possible to maintain good slurry properties during the second stage polymerization, which is high-temperature polymerization, and it is possible to perform continuous polymerization operations smoothly, and to obtain products with high bulk specific gravity in high yield. be able to. On the other hand, in the second stage polymerization, a homopolymer of propylene is polymerized at a high temperature of 70 to 90°C. By providing this step, a polymer with extremely excellent transparency can be obtained.

Note that performing other stages of polymerization between the first stage polymerization and the second stage polymerization, or before and after each polymerization operation does not necessarily bring about results that meet the objectives of the present invention. Although it does not particularly impair the effects of the present invention to carry out propylene alone and in the amount of 'Ao' before the first stage polymerization, it is common to carry out copolymerization at other stages or with other olefins. That's not a good thing to say.

The titanium trichloride or titanium trichloride composition used in the present invention is not particularly limited as long as it is used for olefin polymerization. For example, titanium trichloride obtained by reducing titanium tetrachloride with hydrogen, a eutectic of titanium trichloride and metal halide obtained by reducing titanium tetrachloride with a metal,
and a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound, or a titanium trichloride composition obtained by treating these titanium trichlorides with a specific ether compound and then further treating with titanium tetrachloride, or , and those obtained by subjecting these to pulverization, washing, and various other pretreatments.

The carrier catalyst component on which a titanium compound is supported or chemically bonded to be used in the present invention is not particularly limited as long as it is used for olefin polymerization.

For example, silica, alumina, boron oxide, magnesium compounds (magnesium halide, magnesium hydroxyhalide, magnesium hydroxide, magnesium carbonate, magnesium oxide, etc.), etc. are used in the trench, or if necessary, pretreated, titanium tetrachloride, trichloride, etc. Examples include those in which titanium or a titanium trichloride composition is supported or chemically bonded. In addition, the magnesium compound used as a carrier is, for example, an organomagnesium compound and compound.
It may be one synthesized by reaction with a rogensated silane, or one prepared by dissolving magnesium oxide in alcohol or the like and then precipitating it.

Regarding these catalyst components containing titanium as an active ingredient,
A titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound, or a titanium trichloride composition obtained by treating this titanium trichloride composition with a specific ether compound and then further treating it with titanium tetrachloride, or It refers to magnesium halide synthesized by the reaction of an organomagnesium compound and a halogenated silane, or a magnesium halide that is precipitated after dissolving magnesium in alcohol or the like, and then supports titanium tetrachloride. Generally speaking, the particle size distribution of polyolefins produced when olefins are polymerized is narrow, and polymerization using the method of the present invention using a catalyst component containing titanium as an active ingredient, which can produce polyolefins that are spherical or close to spherical, has a high yield. You can get the product at a reasonable rate.

In particular, a titanium trichloride composition obtained by reducing titanium tetrachloride as a catalyst component mainly composed of titanium with an organoaluminum compound, or a titanium trichloride composition obtained by reducing titanium tetrachloride with an organoaluminum compound as a catalyst component, or a titanium trichloride composition obtained by treating titanium trichloride with a specific ether compound, and then further reducing the titanium tetrachloride composition with a specific ether compound. If a titanium trichloride composition treated with titanium is used and polymerized by the method of the present invention, a product can be obtained in high yield.

The organoaluminum compounds used in the present invention include:
For example, triethylaluminum, triimbutylaluminum, tri-n-propylaluminum, diethylaluminium monochloride, diethylaluminum monobromide, diethylaluminum monoiodide, diethylaluminium monoethoxide, diimbutylaluminum monoisobutoxide, diethylaluminum mono Examples include hydride, diisobutylaluminum monobitride, and ethylaluminum sesquichloride, and one or more of these can be used.

The catalyst component used in the present invention is a catalyst containing titanium as an active component, such as the above-mentioned (AJ titanium trichloride or titanium trichloride composition, or (B) a carrier catalyst component supported or chemically bonded with a titanium compound). It is necessary to use two components, the component and (q) organoaluminum compound, but in addition to these components, a third component may be added as necessary.This third component is generally an electron donor and These include ethers, alcohols, esters, amines, organic phosphorus compounds, etc., and one or more of these are used.

In the present invention, the polymerization temperature in the first stage polymerization is 65°C.
Below, Fi is preferably 40-55°C.

When the temperature exceeds 65°C, crystallinity decreases, the slurry properties in the second stage polymerization deteriorate, and continuous operation of the polymerization becomes difficult. On the other hand, if the temperature is too low than this temperature, the polymerization activity will be low, which will be disadvantageous in industrial production.

In addition, the polymerization ratio in the first stage polymerization is 5 to 35 of the total polymerization amount.
Must be in weight percent. If this portion is less than 5% by weight, the properties of the slurry in the second stage polymerization section will be poor and continuous polymerization will be difficult. Furthermore, if this portion is 35% by weight or more, the transparency will be poor and it will not be suitable for the purpose of the present invention.

In the present invention, the polymerization temperature in the second stage polymerization is 70-90
It is ℃. If the temperature is below 70°C, the transparency will be poor and it will not be possible to obtain a material suitable for the purpose of the present invention.

Moreover, if the temperature exceeds 90°C, the polymer will swell and continuous polymerization will become difficult.

The polymerization in the present invention is carried out in the presence of an inert solvent or liquid propylene, and the polymerization pressure is 50 atm or less, preferably normal pressure to 45 atm.

Furthermore, the polymerization of the present invention can generally be carried out in the presence of hydrogen by controlling the molecular weight to prevent the formation of high molecular weight polymers that adversely affect transparency and cause fish eyes. It's convenient.

The propylene polymer polymerized by the method of the present invention has good transparency and is suitable for blow grade for films or food containers, making it very useful industrially. The yield is also improved, making it a very advantageous method for industrial production.

EXAMPLES In order to explain the present invention more clearly, Examples are shown below, but the scope of the present invention is not limited thereby.

Example 1 Using two polymerization tanks connected in series, two stages of polymerization, ie, first stage polymerization and second stage polymerization, were carried out in each. The first stage polymerization tank has a capacity of 200, and the second stage polymerization tank has a capacity of 500.

(First Stage Polymerization) Into the first stage polymerization tank with a capacity of 200-e, each charging rate was set to 100-Vhr of heptane and 45-Vhr of activated titanium trichloride composition. /h
r, diethylaluminum crophyte 72 f/hr
.

Hydrogen was continuously charged at 27.9 Kv/hr of propylene and hydrogen concentration was 107 by volume in the rat phase, and polymerization was carried out continuously at 50° C. and 6.1 K/G.

(Second stage polymerization) One volume of the first stage polymerization slurry was placed in a second stage polymerization tank with a capacity of 5002.
Continuous liquid transfer at 27.9 Ky/hr, heptane charging rate 344/h, propylene at the same rate (53 Kg/h
Hydrogen was charged continuously at 75℃6,7K1 so that the gas phase hydrogen concentration was 193% by volume.
Polymerization was carried out continuously at 0.

The polymerization slurry is continuously transferred to a post-treatment tank following the second stage polymerization tank, methanol is charged at 274/hr to stop the polymerization, and it is purified, filtered, and dried by a conventional method.
A powdery polymer of 1 Kg/hr was obtained.

Also, the amount of amorphous polymer in 'f''i liquid is 1.9 Kg/'
hr, and the product yield was 972 h.

The ratio of polymerization leaves in the first-stage polymerization section and the second-stage polymerization section was 19:81.

This powdery polymer contains 2,6-di-t-butyl-P.
- Cresol 01% by weight, Kanosy/um stearate 0
1% by weight, di-lauryl-thio-di-propione-10
05% by weight, anti-blocking agent 004% by weight, lubricant 0
．． After uniformly mixing 1% by weight and extruding into pellets, a P film was formed using a T-die film forming machine. The degree of haze and Young's modulus were measured using the obtained film having a thickness of 60 μm.

The results were 23% and 88.1 Kg/mtl, respectively.

In addition, this powdery polymer contains 0.15% by weight of 2.6-di-t-butyl-P-cresol, 01% by weight of calcium stearate, 01% by weight of di-lauryl-thio-di-propionate, and 035% by weight of an antiblocking agent. weight%,
After uniformly mixing 0.2% by weight of oleylamide and extruding it into a pellet shape, the degree of haze and Young's modulus were measured using a 60μ thick blown film formed by an inflation film forming machine, and each was 3.5. %, 87.
It was 8 Kg/*d.

Example 2 In Example 1, the propylene charging rate in the first stage polymerization was 9.0 Kg/hr, and the polymerization pressure was 1.9 K10.
, slurry transfer rate to the second stage polymerization tank 109.0 kg
A polymerization test was conducted in the same manner as in Example 1, except that the propylene charging rate in the second stage polymerization was 75.1 Kg/hr, and the polymerization pressure was 7.8 K/G.
The polymerization conditions shown in 1 were obtained, and the physical properties of the obtained polymer were measured. The results are also shown in Table 1.

Example 3 In Example 1, the activated titanium trichloride composition charging rate k 60 in the first stage polymerization? /hr, and the diethylaluminum chloride charging rate was 96 t/hr.

Propylene charging rate: 39.6 Kg/hr, polymerization pressure: 7.4 to 10, slurry transfer rate to the second stage polymerization tank: 1
39.6 Kt)/hr, the propylene charging rate in the second stage polymerization was 42.4 Kg/hr, and the polymerization pressure was 4.
．． A polymerization test was carried out in the same manner as in Example 1 except that the temperature was 2 K/G. Table 1 shows the results of physical property measurements and the polymerization conditions obtained.

Comparative Example 1 In Example 1, the propylene charging rate in the first stage polymerization was 2.5 Kg/hr, the polymerization pressure was 0.1 K/G, and the propylene charging rate in the second stage polymerization was 82.9 K.
A polymerization test was conducted in the same manner as in Example 1, except that the polymerization pressure was 8.2 K/G, and the slurry transfer rate to the second stage polymerization tank was +0.2 K9/hr. The physical properties of the polymer were also measured. The results are shown in Table-1.

Comparative Example 2 In Example 1, the charging rate of activated titanium trichloride composition in the first stage polymerization was 89.4 S'/hr, the charging rate of diethylaluminum chloride was 1430 f/hr,
The propylene charging rate was 43.3 Kg/hr, the polymerization pressure was f 6.5 K10, the slurry transfer rate to the second stage polymerization tank was 143.3 Kg/hr, and the propylene charging rate in the second stage polymerization was 28.0. Kg/hr, polymerization pressure 2
．． Polymerization test l was carried out in the same manner as in Example 1 except that 3 K/G was used.
- was carried out, and the physical properties of the obtained polymer were also measured.
I got the result.

Example 4 In Example 1, the propylene charging rate in the first stage polymerization was 17. OK9/hr, polymerization temperature 63°C, polymerization pressure 4.5 K/G, gas phase hydrogen concentration 48 volume, slurry transfer rate to the second stage polymerization tank 117.0 Kg/hr, and Propylene charging speed 653Kg/
A polymerization test was carried out in the same manner as in Example except that hr, polymerization pressure cuff, and 2K10 were used, and the physical properties of the obtained polymer were also measured, and the results shown in Table 1 were obtained.

Example 5 In Example 1, the propylene charging rate in the first stage polymerization was 33.8 Kg/hr, and the polymerization pressure was 7.1 K/G.
and the propylene charging rate in the second stage polymerization is 45.4
Kg/hr, polymerization temperature 80℃, polymerization pressure cuff, 6 K/
G: A polymerization test was carried out in the same manner as in Example 1, except that the gas phase hydrogen concentration was 12 volumes, and the slurry transfer rate to the second stage polymerization tank was 133.8 Kg/hr, and the physical properties of the obtained polymer were The measurements were carried out and the results shown in Table 1 were obtained.

Comparative Example 3 In Example 1, in the first stage polymerization, the propylene charging rate was 8.3 Kg/hr, the polymerization temperature was 70°C, the polymerization pressure was 2.3 K/G, and the gas phase hydrogen concentration was 3.2 volumes. Second
Slurry transfer rate to stage polymerization tank 108.2 Kg/hr
, propylene charging speed W in second stage polymerization 75.8
A polymerization test was carried out in the same manner as in Example 1 except that the polymerization pressure cuff was 7 Kg/hr, and the physical properties of the obtained polymer were measured, and the results shown in Table 1 were obtained.

Comparative Example 4 In Example 1, the propylene charging rate in the first stage polymerization was 31.9 Kg/hr, and the polymerization pressure was 6.9 K/G.
, propylene charging rate in the second stage polymerization 54.0 K
g/hr.

Polymerization temperature: 60°C, polymerization pressure: 6.4 K10, gas phase hydrogen concentration: 5.9 volume, slurry transfer rate to the second stage polymerization tank: 1
A polymerization test was carried out in the same manner as in Example 1 except that the rate was 31.9 Kg/hr, and the physical properties of the obtained polymer were also measured, and the results shown in Table 1 were obtained.

Comparative Example 5 In Example 1, the first stage polymerization was not performed and the capacity was 5001
Using only the second stage polymerization tank, heptane 13447hr
, activated titanium trichloride composition 45 Vhr, diethylaluminium chloride 72 fI/hr, propylene 85
．． 9 Kg/hr, hydrogen was continuously charged so that the gas phase hydrogen concentration was 193 volumes, and the temperature was 75°C 8.4 K/(]
The polymerization was carried out continuously, and the physical properties were also measured in the same manner as in Example 1, and the results shown in Table 1 were obtained.

Comparative Example 6 In Example 5, a known nucleating agent, dibenzylidene solpi, was used when extruding the powder polymer into pellets for forming T-die films and inkjet films.
The physical properties were measured in the same manner as in Example 1 except that 2 wt.

It is clear that the effect of the present invention was not achieved in terms of haze level.

Claims (1)

[Claims] (N titanium trichloride or titanium trichloride composition or (
B) When propylene is continuously polymerized using a catalyst consisting of a catalyst component containing titanium as an active component and a (C1 organoaluminum compound), the carrier catalyst component supports or chemically bonds a titanium compound. Polymerization amount of 5~
A method for producing polypropylene with excellent transparency, characterized by carrying out a first stage polymerization of 35% by weight at a temperature of 65°C or lower, and then polymerizing propylene at a temperature of 70 to 90°C.