A high molecular weight olefin polymer and preparation method thereof

Abstract

The invention discloses a high molecular weight olefin polymer, and the raw materials for preparation include 50-99.9 parts by weight of propylene monomer, 0.1-50 parts by weight of double bond monomer, 0.01-0.1 mmol of catalyst I, 1-5 mmol of catalyst II, 8-12 L of inert solvent, and 2-10 mmol of reaction terminator. The present invention adopts titanium complex, organic aluminum compound and organic boron compound as the catalytic system, and the polymerization activity of the catalytic system is not affected by the amount of comonomer addition, and the polymerization stability of the system can be maintained. When producing polymers with different comonomer contents, the brand can be switched for convenient production. And the molar ratio of the organic aluminum compound and the titanium complex is less than 100: 1, while ensuring that the system has high polymerization activity, the amount of the organic aluminum compound is reduced, and it has certain production economy, and at the same time, an olefin copolymer with a large range of propylene content can be prepared, and the adjustable range of polymer performance is wide, which expands the application range of the olefin copolymer.

Description

Technical Field

[0001] The invention relates to a high molecular weight olefin polymer and a preparation method thereof, and relates to C08F, and specifically to the field of copolymers of propylene and alpha-olefin. Background Art

[0002] In order to improve the mechanical properties and processing properties of olefin polymers, the catalytic system of olefins is continuously changed and optimized, and the polymerization process is optimized, so as to improve the performance of olefin polymers and expand their application range. In the traditional Ziegler-Natta catalytic system, the activity of the catalyst will decrease with the change of the amount of monomer. The vanadium-based catalytic system is widely used in the preparation of ethylene-propylene rubber, which can copolymerize ethylene monomers, but the polymer is amorphous, loses crystallinity, and the mechanical properties are reduced. At the same time, the vanadium-based catalyst has low polymerization activity and short life, and the formed product has insufficient aging resistance and processing performance. The catalytic activity of single-site catalysts such as hafnium metal catalysts is lower than that of titanium and zirconium catalysts. Although the polymerization ability is strong, it needs to be activated by a large amount of organic aluminum compounds to show good polymerization activity. In addition, the large-scale use of metal catalysts in the production process will lead to metal residues, which requires a complex metal removal process, and also increases the production cost. Organic aluminum compounds also have a bad impact on the environment.

[0003] Chinese invention patent CN200910184432.1 discloses a method for preparing ethylene-propylene copolymers, wherein a catalyst system consisting of a supported titanium catalyst, an alkyl aluminum co-catalyst, an organosilicon compound and an ether compound double-component composite external electron donor is used to carry out copolymerization of ethylene and propylene, and a copolymerization product containing a large number of long propylene sequence crystalline fractions is prepared, but the molar ratio of the alkyl aluminum co-catalyst to the catalyst titanium is above 100, the amount of the organoaluminum compound used is large, and the cost is high. Chinese invention patent CN90108166.3 discloses a method for preparing ethylene-propylene copolymers, wherein ethylene and propylene are copolymerized under high pressure and high temperature in a reactor vessel in the presence of a co-catalyst containing trialkyl aluminum and a solid catalyst component containing 0.4-4.0% (weight) titanium on a microspherical magnesium chloride carrier, and the copolymer has a high conversion rate and a low density value, but the propylene content is not high, and the molecular weight of the polymer formed is low. Summary of the invention

[0004] In order to increase the propylene content in olefin copolymers and increase the molecular weight of olefin copolymers, the first aspect of the present invention provides a high molecular weight olefin polymer, the preparation raw materials include, propylene monomer 50-99.9 weight parts, double bond monomer 0.1-50 weight parts, catalyst I 0.01-0.1mmol, catalyst II 1-5mmol, inert solvent 8-12L, reaction terminator 2-10mmol.

[0005] As a preferred embodiment, the structural formula of the double bond monomer is R1 is hydrogen or C2-C 10 alkyl

[0006] As a preferred embodiment, R1 is selected from one of H, -CH2, CH3-CH2-CH2-CH2-, H3C-CH(CH3)-CH2-, CH3(CH2)4CH2-. Further preferably, R1 is selected from one of H, -CH2, CH3-CH2-CH2-CH2-.

[0007] As a preferred embodiment, the catalyst I is a titanium complex, the catalyst II is a composition of an organic aluminum compound and an organic boron compound, and the molar ratio of the organic aluminum compound to the titanium complex is (5-100):1.

[0008] As a preferred embodiment, the molar ratio of the organic aluminum compound to the titanium complex is (10-60): 1

[0009] As a preferred embodiment, the glass transition temperature of the high molecular weight olefin polymer is -41 to -10°C.

[0010] As a preferred embodiment, the structural formula of the catalyst I is R2 and R3 are C6-C 25 hydrocarbon group, R2 and R3 may be the same or different, R4 is H or halogen, X is selected from halogen, C1-C 10 Alkyl, C6-C 10 One of the aryloxy groups.

[0011] As a preferred embodiment, R2 and R3 are both selected from one of phenyl, 2-naphthyl, diphenylmethyl, di(2-naphthyl)methyl, and R2 and R3 are the same or different.

[0012] As a preferred embodiment, the R4 is selected from one of H, F, and Cl; the X is selected from Cl, -CH3, One of them.

[0013] The catalyst I and catalyst II may be pre-dispersed or dissolved in an inert solvent.

[0014] As a preferred embodiment, the inert solvent is selected from one or a combination of alkanes, aromatic hydrocarbons, and solvent oils. More preferably, the inert solvent is selected from one or a combination of hexane, heptane, benzene, and toluene.

[0015] As a preferred embodiment, the reaction terminator is ethanol.

[0016] As a preferred embodiment, the organic aluminum compound is selected from one or a combination of alkylaluminoxane, alkylaluminum, and alkylaluminum chloride.

[0017] As a preferred embodiment, the alkylaluminoxane is selected from methylaluminoxane, modified methylaluminoxane, isobutylaluminoxane or a combination thereof.

[0018] As a preferred embodiment, the alkyl aluminum is selected from One or a combination of the following.

[0019] As a preferred embodiment, the alkylaluminum chloride is selected from sesquiethylaluminum, One or a combination of ethylaluminum dichloride.

[0020] As a preferred embodiment, the organic boron compound is selected from one or a combination of tris(pentafluorophenyl)boron, triphenylcarbonium tetrakis(pentafluorophenyl)borate, and N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate.

[0021] As a preferred embodiment, the weight ratio of the organic boron compound to the catalyst I is (0.5-5):1. More preferably, the weight ratio of the organic boron compound to the catalyst I is (1-2):1.

[0022] The present invention uses catalyst I and catalyst II to work together to form a catalytic system in situ in the polymerization reaction system, achieve preactivation, and improve the polymerization activity of the catalyst. The applicant found in the experimental process that when the substituent group of catalyst I is an aromatic group, the polymerization activity of the catalytic system is high, the molecular weight of the prepared copolymer is large, and the polymerization of the copolymer is controllable. It is speculated that the possible reason is that when the prior art catalyzes the copolymerization of propylene monomer and ethylene monomer, it is easy to form an amorphous product with a small molecular weight, low crystallinity, and weak mechanical properties. The catalytic system of the present application uses catalyst I with a substituent group being an aromatic group. Due to the large steric hindrance of the aromatic group, the stereoselectivity of the copolymerized monomer can be controlled, and the occurrence of chain transfer reaction can be suppressed, and the generation of low molecular weight products can be avoided, thereby controlling the morphology of the generated copolymer. The formed copolymer contains a high crystallinity component, and the generated propylene copolymer has good mechanical properties. The catalytic system has the advantages of high polymerization activity, good stereoselectivity, high spatial constraint, and strong copolymerization ability.

[0023] As a preferred embodiment, the polymerization reaction can be carried out in an inert solvent as a homogeneous solution, or in a suspension polymerization using an inert solvent as a suspension medium, or in a liquid monomer, or in a gas phase monomer.

[0024] As a preferred embodiment, the polymerization reaction can be carried out in a batch, multi-step or continuous manner.

[0025] As a preferred embodiment, the raw material for preparing the olefin polymer may further include a molecular weight regulator, and the molecular weight regulator is selected from one or a combination of alkyl aluminum, alkyl zinc, and hydrogen.

[0026] A second aspect of the present invention provides a method for preparing a high molecular weight olefin polymer, comprising the following steps:

[0027] Propylene monomer and double bond monomer undergo polymerization reaction under the action of catalyst I and / or catalyst II, and high molecular weight olefin polymer is obtained after polymerization.

[0028] As a preferred embodiment, the reaction temperature of the polymerization reaction is -50 to 150° C., the polymerization pressure is 0.1-5 MPa, and the polymerization time is 5-60 min. More preferably, the polymerization time is 8-15 min.

[0029] As a preferred embodiment, the method for preparing the high molecular weight olefin polymer comprises the following steps:

[0030] (1) A 20 L high pressure reactor equipped with a stirring device was purged with nitrogen and heated to 70-90° C.;

[0031] (2) Then add 8-12L of inert solvent, introduce a mixed gas of propylene monomer and double bond monomer, maintain the system pressure at 0.1-5MPa, start stirring, and balance for 15 minutes;

[0032] (3) The co-catalyst and the main catalyst are mixed, added into a reactor, and the polymerization reaction is carried out for 8-15 minutes. The reaction is terminated with a reaction terminator and the polymer is precipitated. Then, the polymer is dried at 80° C. under vacuum for 12 hours.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) The high molecular weight olefin polymer of the present invention adopts a titanium complex and an organic aluminum compound as a catalyst system, so that the polymerization activity of the catalyst system is not affected by the amount of comonomer added, the polymerization stability of the system can be maintained, and when producing polymers with different comonomer contents, the brand can be switched, which is convenient for production.

[0035] (2) In the high molecular weight olefin polymer of the present invention, the molar ratio of the organic aluminum compound to the titanium complex is lower than 100:1. While ensuring the system has high polymerization activity, the amount of the organic aluminum compound is reduced, which has certain production economics.

[0036] (3) In the high molecular weight olefin polymer of the present invention, the weight ratio of propylene monomer to double bond monomer is (50-99.9): (0.1-50), which expands the scope of raw material use, increases the propylene content ratio of traditional olefin copolymers, reduces the restriction of raw material usage ratio on the propylene content in olefin copolymers, and improves the group conversion rate. DETAILED DESCRIPTION

[0037] Example 1

[0038] A high molecular weight olefin polymer is prepared from raw materials including 99 parts by weight of propylene monomer, 1 part by weight of double bond monomer, 0.05 mmol of catalyst I, 3.05 mmol of catalyst II, 10 L of inert solvent and 8 mmol of reaction terminator.

[0039] The double bond monomer is ethylene, and the catalyst I is a titanium complex having the structural formula: R2=R3=benzhydryl, R4=H, X=-CH3.

[0040] The catalyst II is a combination of methylaluminoxane and N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, with a molar ratio of 3:0.05.

[0041] The inert solvent is ethane, and the reaction terminator is ethanol.

[0042] A method for preparing a high molecular weight olefin polymer comprises the following steps:

[0043] (1) A 20 L high pressure reactor equipped with a stirring device was purged with nitrogen and heated to 70° C.

[0044] (2) Then, an inert solvent was added, and a mixed gas of propylene monomer and double bond monomer was introduced, the system pressure was maintained at 0.6 MPa, stirring was started, and equilibrium was performed for 15 minutes;

[0045] (3) The co-catalyst and the main catalyst are mixed, added into the reactor, and the polymerization reaction is carried out for 10 minutes. The reaction is terminated with a reaction terminator and the polymer is precipitated. Then, the polymer is dried at 80° C. under vacuum for 12 hours.

[0046] Example 2

[0047] A high molecular weight olefin polymer and a preparation method thereof, the specific steps are the same as those of Example 1, except that the catalyst II is a combination of methylaluminoxane and N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, the molar ratio of which is 2:0.05; the amount of catalyst II used is 2.05 mmol.

[0048] Example 3

[0049] A high molecular weight olefin polymer and a preparation method thereof, the specific steps are the same as those of Example 1, except that the catalyst II is a combination of methylaluminoxane and N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, the molar ratio of which is 1:0.05; the amount of catalyst II used is 1.05 mmol.

[0050] Example 4

[0051] A high molecular weight olefin polymer and a preparation method thereof, wherein the specific steps are the same as those of Example 1, except that 90 parts by weight of propylene monomer and 10 parts by weight of double bond monomer are used.

[0052] Example 5

[0053] A high molecular weight olefin polymer and a preparation method thereof, wherein the specific steps are the same as those of Example 1, except that 80 parts by weight of propylene monomer and 20 parts by weight of double bond monomer are used.

[0054] Example 6

[0055] A high molecular weight olefin polymer and a preparation method thereof, the specific steps are the same as those in Example 1, except that the catalyst I is a titanium complex having the structural formula R2 = phenyl, R3 = benzhydryl, R4 = F, X = -CH3.

[0056] Comparative Example 1

[0057] A high molecular weight olefin polymer and a preparation method thereof, the specific steps are the same as those in Example 1, except that the catalyst I is a pyridylamine hafnium compound with the structural formula Comparative Example 2

[0058] A high molecular weight olefin polymer and a preparation method thereof, the specific steps are the same as those in Example 1, except that the catalyst I is a zirconocene compound with the structural formula Performance Testing

[0059] Performance Testing

[0060] The weight average molecular weight (Mw) of the olefin polymers prepared in Examples 1-6 and Comparative Examples 1-2 was measured by high temperature gel chromatography (HT-GPC).

[0061] The glass transition temperature (Tg) and melting point (Tm) were measured by differential scanning calorimetry (DSC).

[0062] The comonomer content is measured in two cases. For polymers with a propylene content of more than 75%, the comonomer content is measured by Fourier transform infrared spectrophotometer (FTIR). For polymers with a propylene content of less than 75%, the comonomer content is measured by nuclear magnetic resonance (NMR).

[0063] Polymerization activity: The weight of polymer obtained per 1 mol of catalyst per hour is taken as the polymerization activity.

[0064] The test results are shown in Table 1.

[0065] Table 1

[0066]

[0067]

[0068] Note:" * ” means that the DSC curve does not show an obvious signal peak.

Claims

1. A method for preparing a high molecular weight olefin polymer comprises the following steps: (1) Purge a 20L high-pressure reactor equipped with a stirring device with nitrogen and raise the temperature to 70-90°C; (2) Then add 8-12L of inert solvent, introduce a mixed gas of propylene monomer and double bond monomer, maintain the system pressure at 0.1-5MPa, start stirring, and balance for 15 minutes; (3) Catalyst II and Catalyst I are mixed and added into a reactor to carry out polymerization reaction for 8-15 min. The reaction is terminated with a reaction terminator and the polymer is precipitated. The polymer is then dried at 80 °C under vacuum for 12 h. The catalyst I is a titanium complex, the catalyst II is a composition of an organic aluminum compound and an organic boron compound, the molar ratio of the organic aluminum compound to the titanium complex is (5-100):1; the weight ratio of the organic boron compound to the catalyst I is (0.5-5):1; The structural formula of the titanium complex is , wherein R2 and R3 are selected from phenyl, 2-naphthyl, diphenylmethyl, di(2-naphthyl)methyl, R2 and R3 are the same or different, R4 is H or halogen, and X is selected from halogen, C1-C 10 Alkyl, C6-C 10 One of the aryloxy groups.

2. The high molecular weight olefin polymer according to claim 1, characterized in that: The structural formula of the double bond monomer is , wherein R1 is hydrogen or C2-C 10 alkyl.

3. The high molecular weight olefin polymer according to claim 1, characterized in that: The glass transition temperature of the high molecular weight olefin polymer is -41 to -10°C.

4. The high molecular weight olefin polymer according to claim 1, characterized in that: The R4 is selected from one of H, F, and Cl; the X is selected from Cl, -CH3, , One of them.

5. The high molecular weight olefin polymer according to claim 1, characterized in that: The organic aluminum compound is selected from one or a combination of alkylaluminoxane, alkylaluminum, and alkylaluminum chloride.

6. The method for preparing a high molecular weight olefin polymer according to claim 1, characterized in that: The reaction temperature of the polymerization reaction is -50-150°C, and the polymerization pressure is 0.1-5MPa.

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