JPS6340809B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an industrially advantageous method for producing high quality propylene copolymers. More specifically, by using a specific Ziegler-Natsuta catalyst in a specific range of component ratios, we can produce propylene copolymers that are industrially advantageous and have excellent film transparency, stiffness, blocking properties, heat-sealing properties, etc. Relating to a method of manufacturing. Isotactic polypropylene produced with stereoregular catalysts has excellent stiffness, strength, formability,
It is widely used in various molded products because of its excellent appearance and heat resistance. Furthermore, polypropylene films are highly valued for their transparency and stiffness, and are widely used as various packaging materials. One of the drawbacks of polypropylene is that its impact strength is highly dependent on temperature, and its impact strength rapidly decreases from room temperature to 0°C, that is, it has poor cold resistance. Another drawback is that the heat sealing temperature of the film and the shrinkage temperature of the stretched film are too high.For example, with biaxially stretched films, if you try to heat seal them at a temperature that provides sufficient heat sealing strength, heat shrinkage will occur. Heat sealing is virtually impossible because the appearance of the film is impaired. In order to improve these drawbacks of polypropylene, random copolymers such as propylene-ethylene, propylene-butene-1, and propylene-ethylene-butene-1, which are copolymerized with a small amount of α-olefin such as ethylene or butene-1, have been produced. It is used alone or blended with other resins or rubbers as a heat-sealing layer for biaxially oriented polypropylene films, shrink wrapping films, cold-resistant polypropylene films, etc. These propylene copolymers have several problems in terms of production and quality. In terms of production, compared to the production of polypropylene, there is a large amount of worthless amorphous polymer dissolved in the polymerization medium, which not only causes loss of monomer and is economically disadvantageous;
Increased slurry viscosity tends to cause problems in production, such as increased stirring power and decreased heat transfer in the polymerization tank. This phenomenon becomes more pronounced as the attempt is made to produce a copolymer with a high content of comonomers (ethylene, butene-1, etc.) which has excellent cold resistance and heat sealability. On the other hand, in terms of quality, film blocking and slipperiness are generally poorer than polypropylene, and transparency tends to deteriorate over time. This drawback is partially due to the fact that the rigidity is lower than that of polypropylene, but the main cause is that the copolymer contains a large amount of low molecular weight amorphous polymer. These manufacturing and quality issues are generally in a hostile relationship in that trying to improve one will worsen the other. For example,
4992, in which a small amount of polypropylene is formed on a titanium trichloride catalyst in advance and then copolymerized, the amount of worthless amorphous polymer dissolved in the polymerization medium is reduced; As the amount of low molecular weight amorphous polymers contained in the coalescence increases, the above-mentioned quality problems become more noticeable. Furthermore, if a polymerization medium with stronger dissolving power is used to reduce the amount of low molecular weight amorphous polymer contained in the copolymer, the amount of amorphous polymer dissolved in the polymerization medium increases. Therefore, measures are sometimes taken to lower the polymerization temperature, but as is well known, the lower the temperature, the lower the polymerization activity of the catalyst, so if the polymerization time is the same, the amount of catalyst residue remaining in the copolymer increases. Heat stability hue deteriorates. If the polymerization time is increased, a serious problem arises in that productivity decreases. Conventionally, the molar ratio of titanium trichloride and organoaluminum compounds such as triethylaluminum and diethylaluminum chloride, which are generally used in the industrial production of polypropylene, is 1:1 to 1.
It was 20. (See page 26 of "Polypropylene Resin" published by Nikkan Kogyo Shimbun). This can be found in various publications (e.g. Polymerization by C. Reich and A. Schindler, Interscience Publishers).
Organometallic Compounds Chapter D,
Kinetics of Ziegler by T. Keii published by Kodansha
As shown in JP-A No. 47-34478 (Natta Polymerization 4, Chapter 2, etc. and their cited references), when the Al/Ti molar ratio of the catalyst components is less than 1, the catalytic activity and stereoregularity (n- (expressed by the amount of heptane-insoluble parts and crystallinity)
Both decreased rapidly, and the Al/Ti molar ratio decreased to 10.
This is because if the amount is exceeded, the catalytic activity and stereoregularity will decrease. In the production of a propylene copolymer, for example, in the specification of JP-A-49-35487, the B/A molar ratio of the titanium compound (A) and the organoaluminum compound (B) is about 0.5 to 20, preferably There is a description that the range is 1 to 10, and it was common knowledge to practice within the same range. However, the content of propylene targeted by the present invention is 80 to 99 mol%, and the content of ethylene and/or α-olefin having 4 to 18 carbon atoms is 1 to 99 mol%.
To produce 20 mol% propylene copolymer,
Conventional methods have had many of the problems already mentioned. The present inventors have conducted various studies to solve the above-mentioned production and quality problems of propylene copolymers, and as a result, we have developed a specific Ziegler-Natsuta catalyst with a component ratio in a range unimaginable based on conventional knowledge. The inventors have discovered that by using this method, both the manufacturing and quality problems mentioned above can be improved at the same time, leading to the present invention. That is, the present invention uses a Ziegler-Natsuta catalyst to produce a propylene copolymer containing 80 to 99 mol% of propylene and 1 to 20 mol% of ethylene and/or α-olefin having 4 to 18 carbon atoms. In the method for producing a combination, the Ziegler-Natsuta catalyst further comprises (a) a titanium trichloride composition or β-type titanium trichloride obtained by reducing titanium tetrachloride with an organoaluminum compound, and the following (1) or A titanium trichloride solid catalyst activated by the method of (2), (1) a titanium trichloride composition with the general formula X ₂ (X is Cl,
Represents Br and I. ) or an interhalogen compound represented by the general formula XX'a (X and X' represent Cl, Br and I, and a is 1 or 3) and the general formula R ₁ -O-R ₂ (R ₁ and R ₂ have a carbon number of 1 to
It represents eight straight-chain alkyl groups or branched alkyl groups, and R ₁ and R ₂ may be the same group or different groups. )
Titanium trichloride solid catalyst produced by reacting with a mixture with an ether compound represented by (2) β-type titanium trichloride is treated with a complexing agent such as ether, and then treated with titanium tetrachloride. and (b) an organoaluminum compound, characterized in that the molar ratio (b)/(a) of (a) and (b) is 20 to 100. This is a method for producing a propylene copolymer. This catalyst has an activity at least three times higher than that obtained by simply heat-treating a titanium trichloride composition or β-type titanium trichloride (for example, the method described in Japanese Patent Publication No. 39-20501). It has the following. More specifically, it can be obtained, for example, by the method discovered by the present inventors (Japanese Patent Application No. 51-108276). It can also be obtained by the method described in JP-A-47-34478, in which β-type titanium trichloride is treated with a complexing agent such as ether and then treated with titanium tetrachloride. Catalysts other than the catalyst essential to the present invention, such as titanium tetrachloride currently on the market, are reduced with metal aluminum and activated by pulverization (for example, titanium trichloride manufactured by Toho Titanium Co., Ltd.).
The effects of the present invention cannot be achieved with catalysts such as AA) or conventionally known catalysts in which titanium tetrachloride is reduced with an organoaluminum compound and heat treated. Specific examples of the organoaluminum compound used as the catalyst component (b) in the present invention include trialkylaluminum, alkylaluminum halide, alkylaluminum hydride, alkylaluminum alkoxide, and alkylaluminum alkoxyhalide. Specific examples of suitable compounds among these include dimethylaluminum chloride, diethylaluminum chloride, diisobutylaluminum chloride, diethylaluminum bromide, diethylaluminium iodide, ethylaluminum sesquichloride, a mixture of triethylaluminum and diethylaluminium, triethylaluminum and aluminum chloride, and particularly preferred is diethylaluminum chloride. In the present invention, the molar ratio of catalyst components (a) and (b) (b)/
(a) is important; unless a catalyst is used within the range of 20 to 100, preferably 30 to 70, the valueless amorphous polymer dissolved in the polymerization medium will also be reduced. As will be shown later in Examples and Comparative Examples, the molecular weight of the amorphous polymer is not reduced and the effects of the present invention cannot be achieved. In the present invention, the catalyst essentially contains the two components in the above-mentioned specific ratio, but may further contain a known electron-donating compound as a third component.
Such third components include oxygen, nitrogen, sulfur,
Compounds containing phosphorus atoms are common, but aromatic compounds are also well known. Specific examples include saturated or unsaturated aliphatic, alicyclic, and aromatic esters such as ethyl acetate, methyl methacrylate, ethyl benzoate, and ε-caprolactone; ethers such as dibutyl ether and tetrahydrofuran; and butyl. Organic sulfur-containing compounds such as thioether and thiophenol, amines such as triethylamine, tri-n-butylphosphine, triphenylphosphite, tri-n-butylphosphite, tri-n-butylphosphate, hexamethylphosphor These include organic phosphorus compounds such as amides, and aromatic compounds such as benzene, toluene, and azulene. Two or more of these may be used simultaneously. The ratio of the electron-donating compound to the two catalyst components has different effects depending on the type of electron-donating compound, so it is important to find a balance between the allowable degree of reduction in catalyst activity and the amount of atactic polymer generated. There is an appropriate range for each, but in general, the catalyst component
The molar ratio to (a) is about 0.01 to 100. The catalyst consisting of catalyst components (a), (b) or (a), (b) and an electron-donating compound may be charged into the polymerization vessel separately, or in two or three possible ways. Mixed combinations of ingredients can also be used. The composition of the copolymer to which the method of the present invention is applied is:
The content of propylene is 80 to 99 mol%, the content of ethylene and/or α-olefin having 4 to 18 carbon atoms is 1 to 20 mol%, preferably the content of propylene is 85 to 97.5 mol%, ethylene and/or Or the content of α-olefin having 4 to 18 carbon atoms is 2.5 to 2.5
It is 15 mol%. If the content of propylene is higher than this, the effect of the present invention is not significant. Furthermore, if the propylene content is smaller than this, even if the method of the present invention is used, a large amount of amorphous polymer will be dissolved in the polymerization medium, making industrial production difficult. The monomers supplied to the polymerization system are propylene, ethylene and/or α-olefin having 4 to 18 carbon atoms, but butene-olefin is used as α-olefin.
1, pentene-1, heptene-1, 3-methylpentene-1, 4-methylpentene-1, octene-1, decene-1, dodecene-1, tetradecene-1, hexadecene-1, octadecene-1 and these A mixture of two or more types can be used. Particularly preferred among these is butene-
It is 1. Therefore, the resulting copolymers include propylene-ethylene, propylene-butene-1, propylene-ethylene-butene-1 copolymers, and the like. The ratio of monomers supplied to the polymerization system is selected so as to obtain a copolymer with the desired composition, taking into account the monomer reactivity ratio determined by the production conditions (temperature, pressure, type of polymerization medium, catalyst, etc.) . The polymerization is carried out substantially in an inert organic solvent such as aliphatic hydrocarbons such as butane, pentane, hexane, heptane, alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, aromatic hydrocarbons such as benzene, toluene, etc. It is carried out in a liquid phase monomer containing no inert organic solvent or in a gas phase. The polymerization temperature is 0 to 200°C, preferably 30 to 80°C. Polymerization pressure can be any pressure such as normal pressure to 100Kg/
cm ² and can be arbitrarily selected depending on the polymerization method. Molecular weight adjustment can be carried out using various molecular weight modifiers, but the use of hydrogen is common. Polymerization can be carried out either continuously or batchwise. The polymerization time or the average residence time in the polymerization vessel is arbitrary, but in order to produce more economically, the catalyst residue removal step may be substantially omitted, or in order to simplify it, it may be necessary to
It is desirable to select the polymerization time or average residence time under the other polymerization conditions provided so that 8000 parts by weight or more of the copolymer is produced. In order to explain the method of the present invention more clearly, comparative examples and examples are described below, but the present invention is not limited only by these examples.
Note that the characteristic values in the following examples were measured by the following method. (1) Melt index (MI) Based on JIS K6758. (2) Heat sealing temperature A sample with a width of 25 mm obtained by pressing films together using a heat sealer at a predetermined temperature for 2 seconds under a load of 2 kg/cm ² was peeled off at a speed of 200 mm/min.
The temperature at which the peeling resistance obtained by peeling at a peeling angle of 180° was 300 g/25 mm was defined as the heat sealing temperature. (3) Transparency (haze) Based on ASTM D1003. (4) Opening property (blocking) Test pieces that were blocked by treatment at 60° C. for 3 hours under a load of 40 g/cm ² were measured using a blocking tester manufactured by Shimadzu Corporation. (5) Stiffness Based on ASTM D747. Haze, heat seal temperature, and blocking are
A powder copolymer containing an antioxidant, an anti-blocking agent, and a lubricant was granulated using a granulator, and a 30 micron thick film formed using a T-die molding machine was measured. Example 1 (1) Preparation of catalyst (1) Preparation method (preparation of reduction product) After replacing the 200 reaction vessels with argon,
Add 40% dry hexane and 10% titanium tetrachloride, keep this solution at -5℃ and add 30% dry hexane.
, ethylaluminum sesquichloride
A solution consisting of 23.2 was prepared at a temperature of -3°C.
The dropwise addition was carried out under the following conditions. Stirring was then continued at the same temperature for 2 hours. After the reaction, the resulting reduced product was allowed to stand still and was subjected to solid-liquid separation at 0°C, and washed twice with 40 kg of hexane to obtain 16 kg of reduced product. (2) Preparation method The reduction product obtained by the preparation method is slurried in n-decalin, and the slurry concentration is 0.2.
It was heat treated at 140°C for 2 hours as g/cc. After the reaction, the supernatant was extracted and washed twice with 40 ml of hexane to obtain a titanium trichloride composition (A). (3) Preparation method 11 kg of titanium trichloride composition (A) prepared according to the preparation method was slurried in 55% toluene,
Iodine and isoamyl ether were added so that the molar ratio of titanium trichloride composition (A)/I ₂ /diisoamyl ether was 1/0.1/1.0, and the titanium trichloride solid catalyst ( B) was obtained. (2) Production of propylene copolymer A polymerization vessel with an internal volume of 200 and equipped with a stirrer was sufficiently replaced with propylene, and then 68 kg of heptane, 13.6 kg of propylene, and 0.08 kg of ethylene were introduced. The temperature of the polymerization vessel was raised to 60℃, the pressure was 10Kg/ ^cm2 gauge, and the concentrations of ethylene and hydrogen in the gas phase were each 2.2
and 8 mol % of propylene, ethylene and hydrogen. 0.02 mol (3.1 g) of the titanium trichloride solid catalyst (B) and 0.7 mol (84.4 g) of diethylaluminum chloride (DEAC) were added, and copolymerization was started by washing with 2 heptanes. From then on,
Copolymerization was continued for 8 hours by continuously supplying the monomer so that the temperature, pressure, and gas phase composition were maintained constant. After adding isobutanol to stop the copolymerization, 70°C of heptane at 60°C was added and stirred for 30 minutes. The powder copolymer was separated using a centrifuge and dried to obtain 26.5 kg of powder copolymer. In addition, the remaining heptane after separating the powder copolymer is concentrated.
2.0Kg of amorphous polymer was obtained. The weight percentage of powder copolymer to total polymer produced (HIP%) is 93%, and the total amount of polymer produced per titanium trichloride catalyst component is 9200 g/g. The copolymer composition and properties of the powder copolymer are shown in Table 1. Example 2 The same procedure as in Example 1 was carried out except that butene-1, which was calculated to give the desired copolymer composition, was added instead of ethylene. The results are shown in Table 1. Example 3 The same procedure as in Example 1 was carried out except that ethylene and butene-1 calculated to obtain the desired copolymerization composition were added instead of ethylene. The results are shown in Table 1. Example 4 The same procedure as Example 3 was carried out except that the target copolymer composition was changed. The results are shown in Table 1. Example 5, Comparative Example 1 The same procedure as Example 3 was carried out except that the amount of diethylaluminium chloride added was changed. The results are shown in Table 1. Comparative Examples 2 and 3 Titanium trichloride solid catalyst prepared in (1) of Example 1
Titanium trichloride manufactured by Toho Titanium Co., Ltd. instead of (B)
The same procedure as in Example 3 was conducted except that 10 g of AA was added and the amount of diethylaluminum chloride was changed. The results are shown in Table 1. Example 6 (1) Preparation of catalyst (1) Preparation method (preparation of β-type titanium trichloride) After replacing the reactor with argon, 40 parts of dry hexane and 10 parts of titanium tetrachloride were charged.
This solution was kept at -5°C. Then, a solution consisting of 30% of dry hexane and 11.6% of diethylaluminum chloride was added dropwise under such conditions that the temperature of the reaction system was maintained at -3°C or lower. After the dropwise addition was completed, stirring was continued for another 30 minutes, then the temperature was raised to 70°C, and stirring was continued for an additional hour. Next, the β-type titanium trichloride was allowed to stand still for solid-liquid separation, and then washed three times with 40% hexane to yield 15kg.
The reduction product was obtained. The titanium trichloride contains 4.60% by weight Al. (2) Preparation method (Preparation of Lewis base treated solid) β-type titanium trichloride obtained by the above preparation method was suspended in 40% dry hexane, and then β
Diisoamyl ether was added at a molar ratio of 1.2 to the type titanium trichloride, and the mixture was stirred at 40°C for 1 hour. After the reaction was completed, the supernatant liquid was extracted and
It was washed three times with hexane and dried. (3) Preparation method 10 kg of the Lewis base-treated solid prepared according to the above preparation method was added to a solution consisting of 30% dry heptane and 20% titanium tetrachloride, and the mixture was heated at 70°C for 2 hours.
Time processed. After the reaction, the supernatant liquid was extracted, washed three times with 30% hexane, and dried to obtain a titanium trichloride solid catalyst (C). (2) Production of propylene copolymer A polymerization vessel with an internal volume of 200 and equipped with a stirrer was sufficiently replaced with propylene, and then 50 kg of propylene and 0.075 kg of ethylene were introduced. 0.013 mol (2.0 g) of the titanium trichloride solid catalyst (C), 0.54 mol (65 g) of diethylaluminum chloride (DEAC), and 0.02 mol (2.0 g) of methyl methacrylate were added, and the polymerization vessel was immediately heated to 60°C. The temperature rose. Thereafter, monomers were continuously supplied so that the temperature, pressure, and gas phase composition were maintained constant, and copolymerization was continued for 4 hours. In addition,
Molecular weight preparation was done with hydrogen. After the copolymerization was stopped by adding isobutanol, the slurry was washed twice with 50 kg of liquid phase propylene. In this way, 24.2 kg of powdered copolymer was obtained. Additionally, 0.4 kg of amorphous polymer dissolved in washed propylene was recovered. The ratio of amorphous polymer to the total copolymer produced (recovered AP ratio) was 1.6% by weight, and the total amount of polymer produced per titanium trichloride catalyst component was 12.100%.
g/g-Ticl ₃ . The copolymer composition and properties of the powder copolymer are shown in Table 1. Example 7 The same procedure as Example 6 was carried out except that butene-1, which was calculated to give the desired copolymer composition, was added instead of ethylene. The results are shown in Table 2. Example 8 The same procedure as in Example 6 was carried out except that ethylene and butene-1 calculated to obtain the desired copolymer composition were added instead of ethylene. The results are shown in Table 2. Example 9 The same procedure as Example 8 was carried out except that the target copolymer composition was changed. The results are shown in Table 2. Example 10, Comparative Example 4 The same procedure as Example 8 was carried out except that the amount of diethylaluminium chloride added was changed. The results are shown in Table 2.

【table】

【table】 [Brief explanation of drawings]

1 and 2 are flowcharts to aid understanding of the present invention.

Claims (1)

[Claims] 1 Using a Ziegler-Natsuta catalyst, the content of propylene is 80 to 99 mol%, and the content of ethylene and/or α-olefin having 4 to 18 carbon atoms is 1.
In the method for producing ~20 mol % propylene copolymer, the Ziegler-Natsuta catalyst (a) reduces titanium tetrachloride with an organoaluminum compound to obtain a titanium trichloride composition or β-type titanium trichloride; , furthermore, a titanium trichloride solid catalyst activated by the method (1) or (2) below, (1) a titanium trichloride composition with the general formula X ₂ (X is Cl,
Represents Br and I. ) or an interhalogen compound represented by the general formula XX'a (X and X' represent Cl, Br and I, and a is 1 or 3) and the general formula R ₁ -O-R ₂ (R ₁ and R ₂ have a carbon number of 1 to
It represents eight straight-chain alkyl groups or branched alkyl groups, and R ₁ and R ₂ may be the same group or different groups. )
Titanium trichloride solid catalyst produced by reacting with a mixture with an ether compound represented by (2) β-type titanium trichloride is treated with a complexing agent such as ether, and then treated with titanium tetrachloride. and (b) an organoaluminum compound, characterized in that the molar ratio (b)/(a) of (a) and (b) is 20 to 100. A method for producing a propylene copolymer. 2. The method according to claim 1, wherein the catalyst component (b) is an aluminium halide. 3. The method according to claim 1, wherein the molar ratio (b)/(a) of catalyst components (a) and (b) is from 30 to 70. 4 The propylene content of the propylene copolymer is 85
~97.5 mol%, ethylene and/or carbon number 4
The content of ~18 α-olefins is 2.5-15 mol%
The method according to claim 1. 5. The method according to claim 1, wherein the propylene copolymer is a propylene-ethylene copolymer. 6 Propylene copolymer is propylene-butene-
1. The method according to claim 1, which is a copolymer. 7 Claim 1 in which the propylene copolymer is a propylene-ethylene-butene-1 copolymer
The method described in section. 8. The method according to claim 1, wherein the polymerization is carried out in an inert organic solvent. 9. The method according to claim 1, wherein the polymerization is carried out in a liquid phase monomer substantially free of inert organic solvents. 10. The method according to claim 1, wherein 8000 parts by weight or more of the copolymer is produced per 1 part by weight of the catalyst component (a).