JPH0262124B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a method for producing an ethylene copolymer, and more specifically, a method for producing an ethylene copolymer using a catalyst containing a specific transition metal compound and an organometallic compound as main components. The present invention relates to a method for efficiently producing a polymer. [Prior art and problems to be solved by the invention] Conventionally, polyethylene has good water resistance, chemical resistance,
It has excellent electrical properties and is used in a wide range of applications. However, because it is chemically inert,
It has the disadvantage of poor adhesion, printability, and dyeability, which limits its use in applications that require these properties. Therefore, in order to improve such properties of polyethylene, a method is known in which ethylene is copolymerized with an unsaturated carboxylic acid ester or the like. For example, Japanese Patent Publication No. 41-29285 proposes a method of copolymerizing ethylene and an unsaturated carboxylic acid ester using a Ziegler-Natsuta catalyst. However, this method has a problem in that the copolymerization activity is low and therefore not suitable for practical use. Furthermore, JP-A-59-43003 proposes a method of copolymerizing ethylene and unsaturated carboxylic acid ester using a combination catalyst of titanium trichloride and organic aluminum in the presence of a Lewis acid. This method also had the problem that the copolymerization activity was insufficient and the content of unsaturated carboxylic acid ester in the resulting copolymer was extremely low. [Means for Solving the Problems] The present inventors have conducted extensive research in order to develop an extremely efficient method for producing an ethylene copolymer that eliminates the above-mentioned conventional problems. As a result, it was discovered that copolymer activity and conversion rate of unsaturated carboxylic acid ester to copolymer could be improved by carrying out copolymerization using a specific catalyst.Based on this knowledge, the present invention was developed. I have come to complete it. That is, the present invention uses a catalyst mainly composed of [A] a transition metal compound and [B] an organometallic compound,
In producing an ethylene copolymer by copolymerizing ethylene and an unsaturated carboxylic acid ester in the presence of a Lewis acid, which is a halogenated compound in Group 1 of the periodic table, [A] a chromium alkoxy compound as a transition metal compound. , using at least one chromium compound selected from the group consisting of chromium chelate compounds, chromium π-complexes, chromium aryl compounds, and chromium halides;
[B] The present invention provides a method for producing an ethylene copolymer, which is characterized in that an organometallic compound belonging to groups 1 to 10 of the periodic table is used as the organometallic compound. The catalyst used in the method of the present invention has [A] a transition metal compound and [B] an organometallic compound as main components. First, in the method of the present invention, [A] at least one chromium compound selected from the group consisting of a chromium alkoxy compound, a chromium chelate compound, a chromium π-complex, a chromium aryl compound, and a chromium halide is used as the transition metal compound. Here, as the chromium alkoxy compound, a compound represented by the general formula Cr(OR ¹ ) _4-n X ¹ _n ... [] is usually used. R ¹ in this general formula [ ] represents an alkyl group, alkenyl group, cycloalkyl group, aryl group or aralkyl group having 1 to 20 carbon atoms. Specific examples of R ¹ include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, hexyl group, 2-ethylhexyl group, and phenyl group. Also, X ¹ is a halogen atom, that is, chlorine,
Indicates bromine, iodine, etc. m is a real number satisfying 0≦m<4. Specific examples of the compound represented by the above general formula [] include tetramethoxychromium, tetraethoxychromium, tetra-n-butoxychromium, tetra-i-butoxychromium, tetra-t-butoxychromium, tetrahexyloxychromium, and tetrahexyloxychromium. stearyloxychrome, tetraphenoxychrome,
Examples include triethoxychrome monochloride, diethoxychrome dichloride, tri-n-butoxychrome monochloride, tri-t-butoxychrome monochloride, and the like. Further, the chromium chelate compound is specifically chromium trisacetylacetonate represented by the formula Cr(acac) ₃ , chromium tris(2-methyl-1,3-butanedioate) represented by Cr(mbd) ₃ , Cr( _bd ) Chromium tris(1,
3-butanedionate), etc. Here (acac) represents an acetylacetonate group,
Chromium trisacetylacetonate is It is represented by the structural formula. In addition, (mbd) represents a 2-methyl-1,3-butanedioate group, and chromium tris (2-methyl-1,3-butanedioate) is It is represented by the structural formula. Furthermore, (bd) is 1,3
- represents a butanedioate group, and chromium tris(1,3-butanedioate) is It is represented by the structural formula. Examples of chromium π-complexes include biscyclopentadienyl chromium represented by (cp) ₂ Cr ((cp) represents a cyclopencitadienyl group), bisbenzene chromium represented by (C ₆ H ₆ ) ₂ Cr, (2C ₆ H ₅ ) (C ₆ H ₆ )
Diphenylbenzene chromium represented by Cr, formula Dihexamethylbenzenechromium, represented by the formula π-cyclopentadienyl bromochromium acetylacetate, represented by the formula π-cyclopentadienyl(benzene)chromium, represented by the formula Aromatic ring π- such as π-cyclopentadienyl-π-cycloheptadienylchromium represented by
Examples include π-allyl complexes such as tris(η-allyl)chromium and tetrakis(η-allyl)chromium. Furthermore, examples of the chromaryl compound include diphenylchromium, triphenyltris(tetrahydrofuran)chromium, and the like. Next, the preferred chromium halide has the general formula CrX _2o (wherein, X ² represents a halogen atom,
n represents 2 or 3. ). Specific examples include chromium trichloride, chromium tribromide, chromium triiodide, chromium dichloride, chromium dibromide, and chromium diiodide. In the present invention, one or more compounds selected from the above-mentioned specific chromium compounds are used as the transition metal compound [A]. Next, in the method of the present invention, as the organometallic compound [B], an organometallic compound of groups 1 to 10 of the periodic table is used. Here, as the organometallic compound of groups 1 to 10 of the periodic table, a compound represented by the general formula R ² _k MX ³ _ik ...[] is used. R ² in this general formula [ ] represents an alkyl group, alkenyl group, cycloalkyl group, aryl group or aralxy group having 1 to 20 carbon atoms. Specific examples of ^R2 include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, hexyl group, 2-ethylhexyl group, and phenyl group. Further, M represents lithium, sodium, potassium, magnesium, zinc, cadmium, aluminum, boron, gallium, silicon or tin. Furthermore, X ³ is a halogen atom, that is, chlorine,
Indicates bromine, iodine, etc. i is the valence of M,
Usually it is a real number between 1 and 5. k is a real number satisfying 0<k≦i and indicates various values. Specific examples of the compound represented by the above general formula [] include alkyllithium such as methyllithium, ethyllithium, propyllithium, butyllithium, diethylmagnesium, ethylbutylmagnesium, di-n-butylmagnesium, ethylchloromagnesium, ethylbromomagnesium, etc. Alkylmagnesium such as magnesium, dialkylzinc such as dimethylzinc, diethylzinc, dipropylzinc, dibutylzinc, alkylgallium compounds such as trimethylgallium, triethylgallium, tripropylgallium, tributylgallium, triethylboron, tripropylboron, tributylboron, etc. and alkyltin compounds such as tetraethyltin, tetrapropyltin, tributylchlorotin, tetraphenyltin, triphenylchlorotin, and the like. In addition, there are various examples of compounds when M is aluminum, and specifically, trialkylaluminum compounds such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, and diethylaluminum dialkylaluminum monohalides such as monochloride, diethylaluminum monobromide, diethylaluminum monoiodide, diisopropylaluminum monochloride, diisobutylaluminum monochloride, dioctylaluminum monochloride, or methylaluminum sesquichloride, ethylaluminum sesquichloride, ethylaluminum sesquibromide, Alkylaluminum sesquihalides such as butylaluminum sesquichloride are preferred, and mixtures thereof are also preferred. Furthermore, alkyl group-containing aluminoxane produced by the reaction of alkyl aluminum and water can also be used. Among these, aluminum compounds, tin compounds, and magnesium compounds are particularly preferably used. In the method of the present invention, the above-mentioned [A] specific chromium compound used as the transition metal compound, and [B]
There is no particular restriction on the ratio of the organometallic compounds in Groups 1 to 10 of the periodic table used as the organometallic compound, but the ratio of metal atoms in the latter to chromium atoms in the former is usually 0.1 to 5000 (molar ratio), preferably is 1~
The ratio may be 1000 (molar ratio). In the method of the present invention, the above catalyst is used,
An ethylene copolymer is produced by copolymerizing ethylene and an unsaturated carboxylic acid ester in the presence of a Lewis acid. Examples of the Lewis acid include Lewis acid compounds capable of forming a complex with a lone pair of electrons of a polar group, specifically, halogenated compounds of Group 3 of the periodic table. Particularly preferred are halogenated compounds such as aluminum and boron, such as aluminum chloride, aluminum bromide, ethylaluminum dichloride, diethylaluminum dichloride, and boron trichloride, and particularly preferred are aluminum chloride, aluminum bromide, and ethylaluminum dichloride. . In addition, there are no particular restrictions on the unsaturated carboxylic acid ester to be copolymerized with ethylene, but it usually has the general formula A compound represented by is used. In this general formula [], R ³ represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, or an aralkyl group, and R ⁴ represents an alkyl group having 1 to 20 carbon atoms. group, alkenyl group, cycloalkyl group, aryl group or aralkyl group. Further, p represents an integer of 0 to 20. Specific examples of the unsaturated carboxylic acid ester represented by the above general formula [] include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, and benzyl acrylate. Acrylic esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate,
α-substituted acrylic esters such as 2-ethylhexyl methacrylate, phenyl methacrylate, methyl α-chloroacrylate, and ethyl α-chloroacrylate; methyl 3-butenoate, ethyl 3-butenoate, methyl 4-pentenoate, Ethyl 6-heptenoate, methyl 8-nonenoate, methyl 10-undecenoate, propyl 10-undecenoate, butyl 10-undecenoate, hexyl 10-undecenoate, octyl 10-undecenoate, decyl 10-undecenoate,
Examples include carboxylic acid esters having terminal double bonds such as cyclohexyl 10-undecenoate and phenyl 10-undecenoate, and these can be used alone or in combination of two or more. The ratio of the unsaturated carboxylic acid ester to ethylene used as described above may be arbitrarily selected depending on the physical properties required of the intended copolymer. In addition, the ratio of the Lewis acid and unsaturated carboxylic acid ester mentioned above is 1
The Lewis acid is 0.1 to 10 (molar ratio), preferably 0.2 to 1 (molar ratio). There are no particular restrictions on the type of polymerization, including slurry polymerization,
Either solution polymerization, gas phase polymerization, etc. are possible, and both continuous polymerization and discontinuous polymerization are possible.
In this case, fatty acid hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, and halogenated hydrocarbons are used as the polymerization solvent. Specifically, pentane, hexane, heptane, octane, decane, dodecane, cyclohexane, benzene, toluene, xylene,
Ethylbenzene, chlorobenzene, ethylene dichloride, kerosene, etc. are used. As for the polymerization conditions, the reaction pressure is normal pressure to 100Kg/cm ² G, preferably normal pressure to
The reaction temperature is -80 to ²⁰⁰ °C, preferably -50 to 60°C. Incidentally, the reaction time is arbitrary, but it may be normally selected as appropriate between 1 minute and 10 hours. Molecular weight adjustment during polymerization can be carried out by known means, such as hydrogen. [Effects of the Invention] According to the method of the present invention, [A] a specific chromium compound is used as the transition metal compound, and [B] an organometallic compound of Groups ~ of the periodic table is used as the organometallic compound, thereby achieving high activity. It is possible to carry out copolymerization with good yield, and it is also possible to improve the conversion rate of unsaturated carboxylic acid ester to a copolymer. Therefore, the content of unsaturated carboxylic acid ester in the resulting copolymer can be increased. Moreover, the ethylene copolymer obtained by the method of the present invention has improved printability and adhesion, as well as low-temperature flexibility, low-temperature impact resistance, bending crack resistance, and transparency compared to ethylene homopolymers. It has improved characteristics. [Example] Next, the present invention will be explained in more detail with reference to Examples. Example 1 (1) Preparation of catalyst component 2.1 g (6 mmol) of chromium triacetylacetonate was placed in a 200 ml flask purged with argon, and 200 ml of toluene was added thereto to dissolve it. The obtained solution was used as a chromium catalyst component in the following reaction. (2) Production of copolymer In a 500 ml pressure-resistant glass melter replaced with argon,
300ml toluene and 0.97ml ethyl acrylate (8
millimole) and 8 mmol of aluminum trichloride ball-milled under an argon stream, followed by diethylaluminum monochloride.
0.5 mmol and 0.0025 mmol of the chromium catalyst component prepared in (1) above were added. Next, ethylene was introduced into the glass melter, maintained at 2 kg/cm ² G, and a polymerization reaction was carried out at 20° C. for 3 hours. After the reaction was completed, the ethylene was depressurized and the product was poured into methanol to precipitate it. The obtained solid copolymer was separately collected, deashed with a hydrochloric acid-methanol mixture, and extracted with acetone for 5 hours to remove the amorphous polymer. The extraction residue was dried under reduced pressure at 80° C. for 2 hours to obtain 1.32 g of a white copolymer. Catalytic activity (polymerization activity) was 10.1 Kg/g.chromium. When the obtained copolymer was subjected to infrared absorption spectrum analysis, absorption due to carbonyl group was observed at 1730 cm ^-1 position, and absorption due to carbonyl group was observed at 1160 cm ^-1 position.
Absorption due to ether bond was observed at the position. From these absorptions, the content of ethyl acrylate in the copolymer is 9.0wt%, and the conversion rate of ethyl acrylate to the copolymer is 59.6%/
It turned out to be 0.01 mmol chromium.
Furthermore, when the melting point of this copolymer was measured, it was found to be 130°C, which is lower than the melting point of polyethylene produced using the same catalyst (135°C), and a peak based on ethyl branching was observed in nuclear magnetic resonance spectroscopy analysis. This suggests that ethyl acrylate is introduced into the ethylene polymer chain in a manner that disturbs the crystals. The above results are shown in Table 1. Example 2 1.10 g of a copolymer was obtained by carrying out the same operation as in Example 1 (2) except that 0.5 mmol of triethyl aluminum was used in place of diethylaluminium monochloride. The results are shown in Table 1. Example 3 1.56 g of a copolymer was obtained by carrying out the same operation as in Example 1 (2) except that 0.5 mmol of triisobutyl aluminum was used in place of diethylaluminium monochloride. The results are shown in Table 1. Example 4 The amount of chromium catalyst component used was 0.005 mmol,
The amount of diethylaluminum monochloride used
1.0 mmol, and the amount of ethyl acrylate used is
0.85 g of a copolymer was obtained by carrying out the same operation as in Example 1 (2), except that the amount of aluminum trichloride was 20 mmol and the amount of aluminum trichloride used was 20 mmol. The results are shown in Table 1. Example 5 The amount of chromium catalyst component used was 0.005 mmol,
1.21 g of a copolymer was obtained by carrying out the same operation as in Example 1 (2) except that 8 mmol of methyl methacrylate was used instead of ethyl acrylate. The results are shown in Table 1. Example 6 The amount of chromium catalyst component used was 0.005 mmol,
The same procedure as in (2) of Example 1 was carried out except that 1.0 mmol of tetraethyltin was used in place of diethylaluminum monochloride, and 0.92 g of the copolymer was obtained.
I got it. The results are shown in Table 1. Example 7 The amount of chromium catalyst component used was 0.005 mmol,
The same procedure as in Example 1 (2) was carried out, except that 1 mmol of butylethylmagnesium was used in place of diethylaluminium monochloride, to obtain 0.63 g of a copolymer. The results are shown in Table 1. Example 8 (1) Preparation of catalyst component Chromium tetra-t-butoxide 0.556g
(1.61 mmol) was dissolved in 50 ml of toluene.
The obtained solution was used as a chromium catalyst component in the following reaction. (2) Production of copolymer The material obtained in (1) above was used as the chromium catalyst component.
3.44 g of a copolymer was obtained by carrying out the same operation as in Example 1 (2) except that 0.005 mmol was used and the amount of diethylaluminium monochloride used was 1 mmol. The results are shown in Table 1. Example 9 (1) Preparation of catalyst components In a 200 ml flask purged with argon, put 0.95 g (6 mmol) of chromium trichloride, then put 10 stainless steel balls (diameter 5 to 8 mm), and add 150 ml of toluene. Ball milling was carried out at room temperature for 24 hours with stirring. The obtained solution was used as a chromium catalyst component in the following reaction. (2) Structure of copolymer The material obtained in (1) above was used as the chromium catalyst component.
0.64 g of a copolymer was obtained by carrying out the same operation as in (2) of Example 1, except that 0.005 mmol was used and the amount of diethylaluminium monochloride used was 1 mmol. The results are shown in Table 1. Example 10 (1) Preparation of catalyst components In a flask with an internal volume of 200 ml that was purged with argon,
Biscyclopentadienylchromium 1.22g (6.7
mmol) was dissolved in 200 ml of toluene. The obtained solution was used as a chromium catalyst component in the following reaction. (2) Production of copolymer The material obtained in (1) above was used as the chromium catalyst component.
1.9 g of a copolymer was obtained in the same manner as in Example 1 (2) except that 0.005 mmol was used and the amount of diethylaluminium chloride was 1 mmol. The results are shown in Table 1. Example 11 (1) Preparation of catalyst component In a 200 ml flask purged with argon, 1.51 g (7.33 mmol) of diphenylchromium was dissolved in 200 ml of toluene. The obtained solution was used as a chromium catalyst component in the following reaction. (2) Production of copolymer The material obtained in (1) above was used as the chromium catalyst component.
A copolymer was prepared by carrying out the same operation as in Example 1 (2) except that 0.005 mmol was used and the amount of diethylaluminium chloride was 1 mmol.
1.48g was obtained. The results are shown in Table 1. Comparative Example 1 0.46 g of copolymer was obtained by carrying out the same operation as in Example 1 (2) except that 0.0025 mmol of vanadium bisacetylacetonate was used in place of the chromium catalyst component.
I got it. The results are shown in Table 1. Comparative Example 2 Vanadium trichloride instead of chromium catalyst component
The same operation as in Example 1 (2) was carried out except that 0.0025 mmol was used to obtain 0.06 g of a copolymer. The results are shown in Table 1. 【table】

[Brief explanation of drawings]

FIG. 1 is a flowchart representing the catalyst preparation process.

Claims (1)

[Claims] 1. Using a catalyst mainly composed of [A] a transition metal compound and [B] an organometallic compound, ethylene and unsaturation are produced in the presence of a Lewis acid, which is a halogenated compound in Group 1 of the periodic table. When producing an ethylene copolymer by copolymerizing carboxylic acid esters, [A] a chromium alkoxy compound, a chromium chelate compound, a chromium π-
Ethylene, characterized in that at least one chromium compound selected from the group consisting of complexes, chromaryl compounds, and chromium halides is used, and [B] an organometallic compound of Groups 1 to 10 of the periodic table is used as the organometallic compound. Method for producing a copolymer. 2 ^The chromium alkoxy compound has the general formula Cr(OR ¹ _{) 4-} ⁿ The manufacturing method according to claim 1, wherein X ¹ represents a halogen atom, and m is a real number satisfying 0≦m<4. 3. The manufacturing method according to claim 1, wherein the chromium chelate compound is chromium trisacetylacetonate represented by the formula Cr(acac) ₃ (wherein acac represents an acetylacetonate group). 4. The manufacturing method according to claim 1, wherein the chromium π-complex is biscyclopentadienyl chromium represented by the formula (cp) ₂ Cr (wherein cp represents a cyclopentadienyl group) . 5. The manufacturing method according to claim 1, wherein the chromaryl compound is diphenylchromium represented by the formula (C ₆ H ₅ ) ₂ Cr. 6 Chromium halide has the general formula CrX ² _o (wherein,
X ² represents a halogen atom, and n represents 2 or 3. ) The manufacturing method according to claim 1, wherein the chromium halide is represented by: