JPH01272612A - Production of propylene copolymer composition - Google Patents

Abstract

PURPOSE:To obtain the title polymer composition for packaging materials of outstanding transparency and resistance to impact and heat, by polymerization of propylene using a catalyst consisting of a transition metal catalytic component and a halogen- contg. organoaluminum compound followed by copolymerization between ethylene and the rest of the propylene in the presence of an additional halogen-free organoaluminum compound. CONSTITUTION:In the first step, propylene is polymerized using a catalyst consisting of a transition metal catalytic component and an organoaluminium compound of formula I (R<1> is 1-10C alkyl, 6-12C aryl, etc.; X is halogen; 0<n<=2) to produce a propylene homopolymer 1.0-5.0dl/g in intrinsic viscosity [eta]p and >=94% in isotactic pendant fraction so as to account for 60-95wt.% of the whole polymer. In the second step, a second organoaluminum compound of formula II (R<2> is 1-10C alkyl, 6-12C aryl, etc.; 0<m<=3) is added to the system in an proportion of 0.02-3mols per mol of the compound of the formula I and a copolymerization is carried out between ethylene and the rest of the propylene to produce a propylene-ethylene random copolymer 10-80wt.% in ethylene content, satisfying the relationship III for its intrinsic viscosity [eta]Ep so as to account for 40-5wt.% of the whole polymer, thus obtaining the objective polymer composition.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a propylene copolymer composition,
In detail, it has excellent transparency, impact resistance, heat resistance,
The present invention relates to a method for producing a propylene copolymer composition that has well-balanced properties such as rigidity and is suitable for molding materials such as various films, sheets, and injection molded products.

[Prior Art and Problems to be Solved by the Invention] Various propylene polymers have been developed and used as molding materials for films, sheets, and the like. Among these, when a propylene homopolymer is used, a film with excellent transparency can be obtained, but it has the disadvantage of poor impact resistance. Propylene random copolymers containing ethylene as a copolymerization component are also known, but although these have slightly improved impact resistance, they have the problem of poor heat resistance. Furthermore, although films and the like have been formed from block copolymers of propylene and ethylene, their use has been limited due to their opacity.

Under these circumstances, various attempts have been made in recent years to improve the transparency of propylene polymers.

For example, it has been proposed to improve transparency by increasing hydrogen (molecular weight regulator) in the gas phase to about 50 mol% during copolymerization by slurry polymerization (Japanese Patent Publication No. 57
-45251).

However, in this method, the amount of hydrogen in the gas phase increases and the concentrations of propylene and ethylene monomers decrease, resulting in a significant decrease in catalyst activity during copolymerization.

In addition, the homopolymerization activity (catalytic efficiency) must also be lowered accordingly, resulting in a problem that the overall catalyst efficiency is lowered.

The inventors have discovered that transparency, without reducing catalyst efficiency,
We conducted extensive research to develop a method for producing a propylene copolymer composition that has excellent impact resistance, heat resistance, rigidity, and moldability.

[Means to solve the problem]

As a result, in the first step, a propylene homopolymer having an intrinsic viscosity within a certain range and high isotoughness was produced in the presence of a catalyst consisting of a transition metal catalyst component and an organoaluminum, and in the second step, a propylene homopolymer with high isotoughness was produced. The above problem was solved by adding an organoaluminum compound catalyst different from that used in the first step to produce a propylene-ethylene random copolymer having an ethylene content in a certain range and an intrinsic viscosity in a certain range. I found scales. The present invention was completed based on this knowledge.

That is, in the first step, the present invention includes a transition metal catalyst component and the formula A f R', X ! -a ... (I) [
In the formula, RJ is an alkyl group having 1 to 10 carbon atoms.

Represents a cycloalkyl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
X represents a halogen atom, and n is a value satisfying 0<n≦2. However, when n is 1<n≦2, each R1 may be the same or different. ] Propylene is polymerized in the presence of a catalyst consisting of an organoaluminum compound (a) represented by
propylene homopolymer (A
) is produced in an amount of 60 to 95% by weight of the total polymer amount, and then in the second step, - formula % formula % ( ) [wherein Rt is an alkyl group having 1 to 10 carbon atoms.

Represents a cycloalkyl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
m is a value satisfying Ohm≦3. However, m is 1<m
When ≦3, each R2 may be the same or different. ] After adding the organoaluminum compound (b) represented by 0.02 to 3 mol per 1 mol of the organoaluminum compound (a), propylene and ethylene are copolymerized to increase the ethylene unit content. The propylene-ethylene random copolymer (B) having a range of 10 to 80% and an intrinsic viscosity of [η] and satisfying [η) EFT (η:lF+1.5] was added to the total polymer amount of 40 to 5%. The present invention provides a method for producing a propylene copolymer composition, characterized in that the propylene copolymer composition is produced in a proportion by weight.

As described above, the method of the present invention basically involves producing a propylene homopolymer as the component (A) in the first step, and producing a propylene-ethylene random copolymer as the component (B) in the second step. It is something to do.

Here, the propylene homopolymer as component (A) needs to have an intrinsic viscosity [η] of 1.0 to 5.0 dl/g, preferably 1.2 to 4.0 dl/g. g
It is. The intrinsic viscosity [η] is 1. If it is less than Odi/g, the impact resistance will be insufficient, and if it is less than 5, Oa
/g, the moldability of the composition deteriorates significantly.

Furthermore, this propylene homopolymer has an isotactic pentad fraction of 94% or more, preferably 94.5%.
That's all. If the isotactic pentad fraction is less than 94%, the rigidity and heat resistance of the molded article will decrease.

By the way, what is this isotactic pentad fraction?
A, Macr by Z a+gbel li et al.
oa+olecules+-5-, 925 (1973)
It is the isotactic fraction in pentad units in the polypropylene molecular chain measured by the method published in 1999, that is, the method using nuclear magnetic resonance (C-NMR) spectroscopy with carbon isotope.In other words, , the isotactic pentad fraction is the fraction of the propylene monomer unit at the center of a chain in which five consecutive propylene monomer units are meso-bonded.However, regarding peak assignment,
Macromolecules+8, 687(1
975).

Specifically, the isotactic pentad unit is measured as the intensity fraction of the mmmm peak in the total absorption peak in the methyl carbon region of the C-NMR spectrum.

In order to produce a propylene homopolymer as described above, the method of the present invention uses a transition metal catalyst component and a general formula Al
1R'lIX, -1,... (1) [wherein, R',
and n are the same as above. ] Propylene is polymerized in the presence of a catalyst consisting of an organoaluminum compound (a) represented by the following formula. Here, the transition metal catalyst components are:
Titanium halides and the like are preferred, with titanium trichloride and the like being particularly preferred. This titanium trichloride is obtained by reducing titanium tetrachloride by various methods; it is further ball-milled and/or washed with a solvent (for example, washing with an inert solvent and/or an inert solvent containing a radioactive compound). After activation; titanium trichloride or titanium trichloride eutectic (eg, TiCff1s+1/3AfCj!
s) further amine.

Co-pulverized with ether, ester, sulfur, halogen derivative, organic or inorganic nitrogen compound or phosphorus compound, etc.; Obtained by precipitation from liquefied titanium trichloride in the presence of an ether compound; Tokkosho 53-
Examples include those obtained by the method described in Japanese Patent No. 3356. Furthermore, a material in which a titanium halide is supported on a magnesium compound can also be used.

In addition, as the organoaluminum compound (a) represented by formula (1), diethylaluminum monochloride, diethylaluminium heptanobromide, diethylaluminum monoiodide, ethylisobutylaluminum monochloride, jetoxyaluminum monochloride, jetoxy Examples include aluminum monobromide, jetoxyaluminum monoiodide, ethylaluminum sesquichloride, ethylaluminum dichloride, and ethylaluminum dichloride, and one or more of these can be used.

In these catalyst components, the organoaluminum compound (a) is usually 1 to 10% per mole of the transition metal catalyst compound.
They are mixed and used in a ratio of 0 mol.

Further, as the third component, various electron-donating compounds can be used to improve the catalyst performance.

Examples of electron-donating compounds include organic compounds containing oxygen, nitrogen, phosphorus, or sulfur.

Specifically, amines, amides, ketones, nitriles, phosphines, phosphoramides, esters, ethers, thioethers, ethyl esters, acid anhydrides, acid amides, acid halides, and aldevides. , organic acids, organic silane compounds having a 5i-0-C bond, and the like.

As a polymerization method for producing the propylene homopolymer as component (A) in the presence of the above catalyst, known methods can be applied, such as slurry polymerization, solution polymerization, gas phase polymerization, or Examples include bulk polymerization. Gas phase polymerization is particularly preferred since no by-product of active polypropylene is produced.

When producing the propylene homopolymer that is component (A), the propylene used as a raw material may be one used for homopolymerization or copolymerization using a normal Ziegler type catalyst or Ziegler-Natsuta type catalyst, and pure or It is also possible to use a material containing a small amount of a component such as butene that does not interfere with polymerization.

When propylene polymerization is carried out by slurry polymerization, the solvent may be a solvent used for polymerization using a general stereoregular catalyst, such as pentane, hexane, heptane, octane, and nonane.

Examples include inert hydrocarbon solvents such as decane, dodecane, and cyclohexane, among which hexane, heptane, octane, and the like are preferably used.

Various methods can be applied to adjust the molecular weight, but it is usually carried out by introducing an appropriate amount of a molecular weight regulator used in stereoregular polymerization, such as hydrogen gas, into the reaction system.

Here, the polymerization reaction to obtain the propylene homopolymer, which is the component CA), is usually carried out under the following reaction conditions, that is, the reaction temperature is usually 0 to 100°C, preferably 30 to 90°C. C, and the reaction pressure is usually 0.01 to 4.
It is set at 5 kg/cd, preferably in the range of 0.05 to 40 kg/f. It is usually sufficient for the reaction time to be in the range of 0.1 to 10 hours. In this polymerization, it is also effective to prepolymerize propylene at a relatively low temperature and low pressure.

In any case, by making full use of such known methods, the intrinsic viscosity and
[η] may be adjusted within the range of 1.0 to 5.0 a/g and the isotactic pentad fraction may be adjusted to 94% or more.

In the method of the present invention, the ethylene unit content is then
80% by weight, preferably 20-70% by weight, intrinsic viscosity (
η) A propylene-ethylene random copolymer (B
) is manufactured. If the ethylene content is less than 10% by weight, impact resistance will not be improved, and if it exceeds 80% by weight, transparency will decrease. Also, [η], ≧ [η)P+1
．． 5, transparency is not improved.

Such a propylene-ethylene random copolymer (B
), after producing the component (A) (first stage polymerization),
-Formula %Formula %() [In the formula, R1 and m are the same as above. ] is added to the reaction system, an organoaluminum compound (b) represented by
It can be produced by introducing propylene and ethylene and copolymerizing them.

To produce propylene copolymer compositions that produce transparent molded articles, it is necessary to reduce the molecular weight of the copolymer components, and to do this with hydrogen gas, a common molecular weight modifier, Requires large amounts of hydrogen gas and, as a result, the monomer propylene.

The partial pressure of ethylene decreases, causing a decrease in activity. In the present invention, the activity is improved by adding the organoaluminum compound (b) represented by the above general formula (n) to the reaction system, and the low molecular weight propylene-ethylene random copolymer can be produced without hydrogen gas. can be manufactured. .

Furthermore, in the method of the present invention, a highly stereoregular catalyst system is required in the first step to produce a propylene homopolymer with high stereoregularity, but in the second step, a propylene-ethylene random copolymer is required. No crystalline components are required to produce the coalescence. Therefore, in the second stage of polymerization, there is no need to consider stereoregularity much, and catalytic activity is important. Therefore, as the organoaluminum compound added in the second step, one that forms a catalyst system with high activity even if the stereoregularity is low is used.

Here, examples of the organoaluminum compound (b) of the general formula (n) that can be used include triethylaluminum,
Examples include triisobutylaluminum, tri-n-butylaluminum, diethylisobutylaluminum, diethylaluminum hydride, diisobutylaluminum hydride, and one or more of these can be used. Such organoaluminum compound (b) is the organoaluminum compound (a
) 0.02 to 3 mol per mol, preferably 0.1
Add at a rate of ~1.5 mol.

If the amount of the organoaluminum compound (b) added is less than 0.02 mol per 1 mol of the organoaluminum compound (a), the activity improvement effect will not be achieved, and the effect will be saturated at about 3 mol. Therefore, there is no need to add more than -3 mol.

Further, when adding the organoaluminum compound (b), the organoaluminum compound (a) can also be further added.

As mentioned above, in the method of the present invention, the production of component (B) is carried out subsequent to the production of component (A), but before the production of component (B), an organic compound of general formula (II) is added to the reaction system. Add aluminum compound (b).

After adding this organoaluminum compound (b), a mixture of propylene and ethylene is supplied, and the reaction conditions are usually set within the same reaction temperature and pressure range as in the production of component (A) for 9 hours to carry out the copolymerization reaction. All you have to do is

In the present invention, as mentioned above, propylene homopolymer is produced in the first step by 60 to 95% by weight, preferably 70 to 90% by weight of the total polymer amount, and then in the second step, propylene-ethylene random polymer is produced. 40 of the total amount of copolymer
~5% by weight, preferably 30-10% by weight.

The amount of propylene homopolymer is 60% by weight of the total polymer amount
If it is less than 95% by weight, the molded product will have poor rigidity and heat resistance, and if it exceeds 95% by weight, the impact resistance will be insufficient. - The method of the present invention can be carried out by various methods, and although there are no particular limitations, it can usually be suitably carried out in a semi-batch manner or a continuous manner. When carried out in a semi-batch manner, a polymerization tank equipped with a stirring device is generally used. When polymerization is carried out in a continuous manner, a polymerization tank consisting of two or more polymerization tanks connected in series is used, a propylene homopolymer is produced in the first tank, and the catalytic activity of the polymerization product is deactivated. It is preferable that the propylene-ethylene random copolymer be produced by transferring the mixture to the second tank without any liquid.

After removing unreacted monomers, solvents, etc., the polymerization product obtained in this way is subjected to post-processing steps such as washing and drying as necessary to form a powdered propylene copolymer composition. It can be recovered. It is also possible to add additives to the obtained powder as necessary and granulate it into product pellets.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 1.6 d (1,28 xio-" mol) of diethylaluminium chloride was placed at room temperature in a stainless steel autoclave (inner volume 3.51) that had been thoroughly dried and purged with nitrogen gas.
A mixture of 0.2 g of titanium trichloride (manufactured by Marubeni Solvay) and 20 d of n-hexane was added. After the addition, the pressure was reduced to vacuum while stirring to evaporate and remove n-hexane.

After raising the temperature to 70°C and bringing the inside of the autoclave to normal pressure with propylene gas, a predetermined amount of hydrogen gas was introduced.Next, propylene gas was introduced, and the autoclave was heated to 70°C, 28kg/
Polymerization was carried out for 2 hours at constant temperature and pressure using ajG to obtain a propylene homopolymer (A).

After the polymerization was completed, the pressure was released to normal pressure, and 0.8 d (5,85×10-' mol) of triethylaluminum was added. Next, propylene gas was added at a partial pressure of 6 kg/cd.

Ethylene gas was introduced at 3 kg/cd to start polymerization.

Propylene/ethylene mixed gas (1:1 molar ratio) during polymerization
was supplied and copolymerized for 10 minutes while maintaining a pressure of 15 kg/cdG.

After the polymerization was completed, the pressure was released and 10 d of propylene oxide and 2 d of water were added.
- was added and the polymerization was terminated at 80°C for 30 minutes to obtain a white powdery propylene copolymer composition.

After thoroughly drying this powder, 0.1% of butylated hydroxytoluene, 0.15 g of Irganox 1010 (manufactured by Ciba Geigy), and 0.1% of calcium stearate were added.
1% was added, and the mixture was kneaded and granulated into pellets using a single screw extruder at 220'C.

The properties of the obtained component (A), component (B), and copolymer composition were measured, as well as their physical properties. The results are shown in Table 1.

Example 2 Triisobutylaluminum 0.8- was used instead of triethylaluminum, and a mixed gas of propylene and ethylene (propylene:ethylene = 5
The same procedure as in Example 1 was carried out, except that 6 (molar ratio)) was used, polymerization was carried out for 20 minutes, and the production time (copolymerization time) of component (B) was 20 minutes. The results are shown in Table 1.

Example 3 Triethylaluminum 0.4d (2,92X 10-" mol) and diethylaluminium chloride 0.4m (3,19XIO-3
The procedure was the same as in Example 1, except that the amount of hydrogen during the production of the component (A) and the mixed gas ratio of propylene and ethylene during the production of the component (B) were changed. The results are shown in Table 1.

Example 4 In an autoclave with an internal volume of 101 parts and equipped with a stirrer, 5 parts of dehydrated n-heptane were added. was added, 0.6 g of diethylaluminum chloride titanium chloride (manufactured by Marubeni Solvay) was added, propylene (pressure 1 kg/d) was supplied, and prepolymerization was carried out at 25° C. for 30 minutes.

Next, after maintaining the liquidus temperature at 65°C and supplying hydrogen in a measured amount so that the polypropylene produced has a predetermined intrinsic viscosity, the reaction pressure is increased to 8 kg/cn! Propylene was continuously supplied so as to give G, and polymerization was carried out with stirring for 90 minutes to obtain a propylene homopolymer as component (A). Thereafter, unreacted propylene was removed.

To this, triethylaluminum 3-(2,19×104
mol), followed by further feeding of propylene and ethylene at a constant flow rate while maintaining the temperature at 57 °C,
Polymerization was carried out for 20 minutes to obtain a propylene-ethylene random copolymer as component (B).

After the reaction was completed, unreacted monomers were removed, the polymerization product was separated, and a white powdery polymer (copolymer composition) was obtained through a washing process and a drying process.

The properties and physical properties of the obtained component (A), component (B), and copolymer composition were measured. The results are shown in Table 1.

Comparative Example 1 The same procedure as in Example 1 was carried out except that triethylaluminum was not added after producing the propylene homopolymer. The results are shown in Table 1.

Comparative Example 2 The same procedure as in Example 4 was carried out except that triethylaluminum was not added after producing component (A). The results are shown in Table 1.

Comparative Example 3 In Example 1, triethylaluminum was not added after producing component (A), and propylene gas was used at a partial pressure of 6 kg/d and ethylene gas at a partial pressure of 3 kg/c during the polymerization of component (B).
d. Hydrogen gas was introduced at 10 kg/cdl to start polymerization. During polymerization, a propylene/ethylene mixed gas (1:1 molar ratio) was supplied, and the pressure was maintained at 18 kg/cjG.
Copolymerization was carried out for 80 minutes. The following operation was carried out in the same manner as in Example 1. The results are shown in Table 1.

Comparative Example 4 0.05d (1,97X
The procedure was carried out in the same manner as in Example 2, except that IO-'mol) was used. The results are shown in Table 1.

Comparative Example 5 The same procedure as in Example 1 was carried out except that 0.8i of diethylaluminum chloride was used instead of triethylaluminum after producing component (A). The results are shown in Table 1.

Comparative Example 6 The same procedure as in Example 1 was carried out except that triethylaluminum 1.6 was used instead of diethylaluminum chloride during the production of component (A). The results are shown in Table 1.

(Left below) $1 Indicates the ratio of component (A) and component (B) to the total amount.

$2 Measured at 135°C using tetralin as a solvent.

*3 ' Indicates isotactic pentad fraction (ynmmm) according to 3C-NMR spectrum.

*4 Unit indicates g/g-titanium component/time.

*5 Indicates the ratio (molar ratio) of the organoaluminum compound additionally used during the production of the propylene-ethylene random copolymer (B) to the organoaluminum compound used during the production of the propylene homopolymer (A).

$6 Compliant with JIS K 6738.

*7 Compliant with JIS K 673B.

$8 About 300μ press sheet JISK7105
Compliant with.

〔Effect of the invention〕

According to the method of the present invention, the molecular weight of the propylene-ethylene random copolymerization portion can be lowered without increasing the amount of hydrogen during polymerization, and the polymerization activity of this copolymerization portion can be significantly increased.

Furthermore, the propylene copolymer composition obtained by the method of the present invention has excellent transparency comparable to that of propylene homopolymer, and has excellent impact resistance.

It has significantly improved heat resistance and rigidity, and also has excellent moldability.

Therefore, the propylene copolymer composition obtained by the method of the present invention is expected to be effectively used as a molding material for films, sheets, injection molded products, etc. for various uses including containers and packaging for retort food. .

Claims (2)

[Claims] (1) In the first step, the transition metal catalyst component and the general formula AlR
^ 1_n , X represents a halogen atom, and n is a value satisfying 0<n≦2. However, when n is 1<n≦2, each R^1 may be the same or different. ] Propylene is polymerized in the presence of a catalyst consisting of an organoaluminum compound (a) represented by
A propylene homopolymer (A) having a P of 1.0 to 5.0 dl/g and an isotactic pentad fraction of 94% or more is produced in an amount of 60 to 95% by weight of the total polymer, and then in a second step. , general formula AlR^2_mH_3_-_m [wherein R^2 is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, or an alkoxy group having 6 to 12 carbon atoms Indicates an aryl group, m is 0
It is a value that satisfies <m≦3. However, when m is 1<m≦3, each R^2 may be the same or different. ] After adding the organoaluminum compound (b) represented by 0.02 to 3 mol per 1 mol of the organoaluminum compound (a), propylene and ethylene are copolymerized to increase the ethylene unit content. is 10 to 80% by weight, and the intrinsic viscosity [η]_E_P is [η]_E_P<[η]_P+1.
5. A method for producing a propylene copolymer composition, which comprises producing a propylene-ethylene random copolymer (B) in a range satisfying 5 from 40 to 5% by weight of the total polymer amount. (2) The method for producing a propylene copolymer composition according to claim 1, wherein the polymerization and copolymerization are carried out under gas phase conditions.