Disclosure of Invention
The invention provides special resin powder for chlorinated polyethylene and a preparation method and application thereof. The special resin powder for chlorinated polyethylene provided by the invention has relatively low wax content, relatively wide molecular weight distribution and relatively small average particle size, and can obtain a product with the characteristics through optimizing a catalyst system used in the preparation process of the special resin powder for chlorinated polyethylene.
In order to achieve the purpose, the invention provides the following technical scheme:
the invention provides special resin powder for chlorinated polyethylene, which is polyethylene or a copolymer of ethylene and alpha-olefin, and the powder density of the special resin powder for chlorinated polyethylene is 0.945-0.960 g/cm3,MFR5kg0.1-10 g/10min, an average particle size of 100-.
In the art, the wax in the chlorinated polyethylene specialized resin powder is generally an oligomeric wax having a weight average molecular weight of 500-.
Further, the alpha-olefin is propylene, butene-1, hexene-1, octene-1 or 4-methylpentene-1.
The invention also provides a preparation method of the resin powder special for chlorinated polyethylene, wherein ethylene and optional alpha-olefin are subjected to slurry polymerization reaction in a single slurry reaction kettle in the presence of a catalyst to prepare the resin powder special for chlorinated polyethylene, wherein the catalyst comprises an antimony element modified supported chromium-based catalyst, and the average particle size of the antimony element modified supported chromium-based catalyst is preferably 6-20 μm.
By adopting the preparation method, the antimony element modified supported chromium catalyst is adopted to produce the special resin powder for the chlorinated polyethylene, and the advantages of low wax content, wide molecular weight distribution and small average particle size can be obtained. Moreover, the reaction of the invention can be carried out in a single slurry reaction kettle, and the process of generating micromolecules in the first step during step reaction is avoided, thereby reducing the production of oligomer wax; and the reaction is carried out in a single reaction kettle, so that the process parameters are easy to control, and the process control difficulty is greatly reduced. The chlorinated polyethylene produced by the special resin powder provided by the invention has the advantages of high chlorination rate, stable chlorination pressure and uniform chlorine distribution, and the obtained chlorinated polyethylene has excellent processability while maintaining good mechanical properties.
Preferably, the antimony-modified supported chromium-based catalyst is added in an amount of 0.02 to 2mg, preferably 0.03 to 0.2mg, per gram of ethylene.
Further, the catalyst also comprises a cocatalyst which is an aluminum alkyl, preferably the cocatalyst is one or more of triethylaluminum, triisobutylaluminum, ethoxydiethylaluminum, monochlorodiethylaluminum or methylaluminoxane, and more preferably triisobutylaluminum;
preferably, the amount of the cocatalyst is 0.01-10mL, preferably 0.05-1mL, per mg of the antimony-modified supported chromium-based catalyst.
Further, the amount of the antimony element is 0.01 to 5 wt%, preferably 0.02 to 1 wt%, based on the total weight of the antimony element modified supported chromium-based catalyst.
In a preferred embodiment, the preparation of the antimony modified supported chromium-based catalyst comprises:
1) putting a supported chromium catalyst (used as a carrier) into a tubular furnace, loading an antimony element in an antimony compound onto the supported chromium catalyst through vapor deposition, and roasting to obtain a precursor;
2) the precursor obtained in the step 1) is subjected to reduction reaction in the presence of an organic metal reducing agent, a catalyst of low-valence active metal elements is obtained through reduction, and the obtained reduction product is dried to obtain the antimony element modified supported chromium catalyst.
In some embodiments, the vapor deposition in step 1) is performed under an inert atmosphere, and the flow rate of the inert gas is 5-100 mL/min, preferably 40-60 mL/min; the reaction temperature in the step 1) is 100-600 ℃, and preferably 300-550 ℃; the deposition time is 120-480 min, preferably 180-300 min. In the step 1), roasting is carried out in inert gas, the roasting temperature is 300-1000 ℃, preferably 400-800 ℃, the time is 1-10 hours, preferably 4-6 hours, and then cooling is carried out; or the roasting is carried out in two stages, namely a low-temperature stage and a high-temperature stage, wherein the low-temperature stage is carried out at 100-300 ℃ for 1-10 hours, preferably 4-8 hours, and the high-temperature stage is carried out at 300-900 ℃ for 1-10 hours, preferably 4-8 hours.
In some embodiments, in step 2), the reduction reaction is carried out under an inert atmosphere, and the reduction temperature is 20 ℃ to 100 ℃, preferably 20 ℃ to 70 ℃; the reduction time is 0.5 to 20 hours, preferably 0.5 to 10 hours.
The inert gas used is not particularly limited, and nitrogen is preferred.
In step 1), the supported chromium-based catalyst used may be a commercially available product such as the additive C-series catalyst from Basell corporation.
In some embodiments, in step 1), the antimony compound is selected from one or more of antimony trioxide, antimony pentoxide, antimony trichloride, antimony pentachloride, sodium antimonate, sodium hexafluoroantimonate and antimony acetate, and preferably antimony trioxide.
In some embodiments, in step 2), the organometallic reducing agent is one or more of triethylaluminum, triisobutylaluminum, diethylaluminum ethoxide, diethylaluminum monochloride or methylalumoxane, preferably diethylaluminum ethoxide; preferably, the molar ratio of aluminum to chromium is preferably 0.01 to 500, more preferably 0.1 to 50, based on the aluminum element in the organometallic reducing agent and the chromium element in the supported chromium-based catalyst.
In some embodiments, the slurry polymerization is carried out in a single slurry reactor in the presence of the catalyst in an alkane solvent as a medium;
the slurry polymerization reaction is carried out at a reaction temperature of 70 to 85 ℃ preferably 75 to 82 ℃, a reaction pressure of 0.5 to 1.5MPa preferably 0.8 to 1.2MPa, a molar ratio of hydrogen to ethylene of 0.01 to 1, preferably 0.02 to 0.1, and a molar ratio of alpha-olefin to ethylene of 0 to 0.1, preferably 0.01 to 0.04.
In a specific embodiment, the preparation method of the resin powder special for chlorinated polyethylene specifically comprises the following steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 70-85 ℃;
(2) feeding hydrogen and optionally an alpha-olefin to the slurry reactor in a hydrogen to ethylene molar ratio of 0.01 to 1 and an alpha-olefin to ethylene molar ratio of 0 to 0.1;
(3) introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.5-1.5 MPa;
(4) adding a catalyst into the slurry reactor to perform a slurry polymerization reaction, for example, for 1 to 5 hours (for example, for 3 hours); in the polymerization reaction process, the pressure in the reaction kettle is kept relatively stable through the introduction of ethylene;
(5) venting the pressure in the slurry reactor and reducing the temperature of the slurry reactor contents, e.g., to 20 ℃, by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The alkane solvent is used as a polymerization dispersant, and preferably, the alkane solvent is one or more of butane, pentane, n-hexane or heptane; n-hexane is preferred.
The invention also provides application of the special resin powder for chlorinated polyethylene in a preparation process of chlorinated polyethylene.
The invention adopts the antimony modified supported chromium catalyst which has multiple active centers, each active center has different chain transfer rate and chain growth constant, the obtained product has the characteristics of large melt strength, wide processability and the like, and no obvious by-products such as low molecular wax and the like are generated during polymerization. By optimizing the catalyst system, the invention can overcome the problems of high wax content, narrow molecular weight distribution, large product particle size and the like of the special resin prepared by the existing slurry polymerization process of the special resin for chlorinated polyethylene; the special resin for chlorinated polyethylene provided by the invention is beneficial to solving the problems that the existing special resin is uneven in chlorination, easy to stick to a kettle and incapable of considering good processability and mechanical properties when used for downstream production of chlorinated polyethylene.
According to the special resin powder for chlorinated polyethylene, the chlorinated polyethylene is prepared through downstream chlorination, so that the problems of overhigh chlorination pressure, easy kettle adhesion, low chlorination rate and the like in the chlorination process can be solved.
Detailed Description
In order to better understand the technical solution of the present invention, the following examples are further provided to illustrate the present invention, but the present invention is not limited to the following examples.
Description of the Performance test method of the resin powder specially used for chlorinated polyethylene:
density: reference GB/T1033.2-2010
MFR21.6kgAnd MFR5kg: reference GB/T3682-
Bulk density: reference GB/T1636-
Wax content: weighing about 10g of special resin powder sample for chlorinated polyethylene, putting the special resin powder sample into an extraction paper cylinder with known weight, and putting the paper cylinder and the sample (m)1) The mixture was put into an extractor containing n-heptane, and the extractor was put into a constant temperature oil bath and extracted at 80 ℃ for 6 hours. After extraction, the extraction paper tube containing residual polymer is placed in a vacuum oven, dried to constant weight at 90 ℃, then moved into a silica gel drying oven, cooled for 30 minutes, weighed and recorded as m2(to the nearest 0.1mg), wax content ═ m1-m2)*100%/m1。
S value: s value of the polymer is MFR21.6kgAnd MFR5kgRatio of
Average particle size: the method is carried out on a Beckman Coulter LS230 type laser particle size analyzer, and the particle size measuring range is 0.04-2000 microns.
Description of the chlorinated polyethylene performance detection method:
chlorine content/%: refer to the B method in GB/T7139-.
Mooney viscosity: reference is made to GB/T1232.1-2000.
Shore hardness: reference is made to GB/T531.1-2008.
Tensile strength: the method is carried out according to GB/T528-.
Elongation at break: reference is made to GB/T1340.1-2006.
Example 1
Example 1 a resin powder for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is n-hexane, and the stirring speed is 500 rpm.
(2) Adding hydrogen and alpha-olefin into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.04, and the molar ratio of the alpha-olefin to the ethylene is 0.02; wherein the alpha-olefin is hexene-1.
(3) Introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.80 MPa;
(4) adding an antimony modified supported chromium catalyst and a cocatalyst into a slurry reaction kettle to perform slurry polymerization reaction (wherein the dosage of the antimony modified supported chromium catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triisobutylaluminum), and reacting for 3 hours; in the polymerization reaction process, introducing ethylene to maintain the relative stability of the pressure in the reaction kettle, and reacting 423g of ethylene;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The properties of the resin powder for chlorinated polyethylene obtained in example 1 were as follows: the density is 0.949g/cm3,MFR5kg2.1g/10min, and a bulk density of 0.41g/cm3The wax content was 0.38%, the S value was 25, and the average particle diameter was 259. mu.m.
Example 2
Example 2a resin powder for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is n-hexane, and the stirring speed is 500 rpm.
(2) Adding hydrogen and alpha-olefin into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.02, and the molar ratio of the alpha-olefin to the ethylene is 0.01; wherein the alpha-olefin is butene-1.
(3) Introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.85 MPa;
(4) adding an antimony modified supported chromium catalyst and a cocatalyst into a slurry reaction kettle to perform slurry polymerization reaction (wherein the dosage of the antimony modified supported chromium catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triisobutylaluminum), and reacting for 3 hours; 486g of ethylene is reacted in total by introducing the ethylene to maintain the relative stability of the pressure in the reaction kettle in the polymerization reaction process;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The properties of the resin powder special for chlorinated polyethylene obtained in example 2 are as follows: the density was 0.956g/cm3,MFR5kg1.1g/10min, and a bulk density of 0.40g/cm3The wax content was 0.23%, the S value was 29, and the average particle diameter was 241 μm.
The antimony-modified supported chromium-based catalyst used in example 1-2 was prepared as follows:
a) fully mixing a supported chromium catalyst and an antimony compound, and then placing the mixture in a tubular furnace, wherein the supported chromium catalyst is Advent C, and the antimony compound is antimony trioxide. The temperature was raised to 500 ℃ at 10 ℃/min under a nitrogen atmosphere (flow rate 50mL/min) and maintained for 3 hours. Then roasting in nitrogen atmosphere at 600 ℃ for 5h, and then naturally cooling to obtain the precursor.
b) And c) carrying out reduction reaction on the precursor obtained in the step a) in the presence of an organic metal reducing agent under the nitrogen atmosphere, and drying the obtained reduction product to obtain the antimony element modified supported chromium catalyst. Wherein the organic metal reducing agent is ethoxy diethyl aluminum, the reduction temperature of the reduction reaction is 20 ℃, the reduction time is 1 hour, and the molar ratio of aluminum to chromium is 40 based on the aluminum element in the organic metal reducing agent and the chromium element in the supported chromium catalyst.
In the obtained antimony element-modified supported chromium-based catalyst, the amount of antimony element supported was 0.3% by weight based on the total weight of the antimony element-modified supported chromium-based catalyst, and the average particle diameter was 14 μm.
Example 3
Example 3 a resin powder for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is n-hexane, and the stirring speed is 500 rpm.
(2) Adding hydrogen and alpha-olefin into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.08, and the molar ratio of the alpha-olefin to the ethylene is 0.02; wherein the alpha-olefin is butene-1.
(3) Introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.85 MPa;
(4) adding an antimony modified supported chromium catalyst and a cocatalyst into a slurry reaction kettle to perform slurry polymerization reaction (wherein the dosage of the antimony modified supported chromium catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triethylaluminum), and reacting for 3 hours; 376g of ethylene is reacted in total by introducing the ethylene to maintain the relative stability of the pressure in the reaction kettle in the polymerization reaction process;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The properties of the resin special for chlorinated polyethylene obtained in example 3 are as follows: the density was 0.952g/cm3,MFR5kg2.7g/10min, and a bulk density of 0.41g/cm3The wax content was 0.46%, the S value was 24, and the average particle diameter was 255 μm.
Example 4 (without alpha-olefin)
Example 4 a resin powder for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is normal hexane, and the stirring speed is 500 rpm;
(2) adding hydrogen into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.02;
(3) introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.85 MPa;
(4) adding an antimony modified supported chromium catalyst and a cocatalyst into a slurry reaction kettle to perform slurry polymerization reaction (wherein the dosage of the antimony modified supported chromium catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triisobutylaluminum), and reacting for 3 hours; 486g of ethylene is reacted in total by introducing the ethylene to maintain the relative stability of the pressure in the reaction kettle in the polymerization reaction process;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to room temperature of 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
Example 4 preparation ofThe properties of the obtained special resin powder for chlorinated polyethylene are as follows: density 0.964g/cm3 MFR5kg0.96g/10min, and a bulk density of 0.39g/cm3The wax content was 0.28%, the S value was 26, and the average particle diameter was 244 μm.
The preparation of the antimony modified supported chromium catalysts used in examples 3-4 was as follows:
a) fully mixing a supported chromium catalyst and an antimony compound, and then placing the mixture in a tubular furnace, wherein the supported chromium catalyst is Advent C, and the antimony compound is antimony pentoxide. The temperature was raised to 500 ℃ at 10 ℃/min under a nitrogen atmosphere (flow rate 50mL/min) and maintained for 3 hours. Then roasting in nitrogen atmosphere at 600 ℃ for 5h, and then naturally cooling to obtain the precursor.
b) And c) carrying out reduction reaction on the precursor obtained in the step a) in the presence of an organic metal reducing agent under the nitrogen atmosphere, and drying the obtained reduction product to obtain the antimony element modified supported chromium catalyst. Wherein the organic metal reducing agent is methylaluminoxane, the reduction temperature of the reduction reaction is 20 ℃, the reduction time is 1 hour, and the molar ratio of aluminum to chromium is 40 based on the aluminum element in the organic metal reducing agent and the chromium element in the supported chromium catalyst.
In the obtained antimony element-modified supported chromium-based catalyst, the amount of antimony element supported was 0.3% by weight based on the total weight of the antimony element-modified supported chromium-based catalyst, and the average particle diameter was 14 μm.
Example 5
Example 5 a resin powder for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is n-hexane, and the stirring speed is 500 rpm.
(2) Adding hydrogen and alpha-olefin into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.02, and the molar ratio of the alpha-olefin to the ethylene is 0.01; wherein the alpha-olefin is butene-1
(3) Introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.80 MPa;
(4) adding an antimony modified supported chromium catalyst and a cocatalyst into a slurry reaction kettle to perform slurry polymerization reaction (wherein the dosage of the antimony modified supported chromium catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triisobutylaluminum), and reacting for 3 hours; in the polymerization reaction process, 516g of ethylene is reacted together by introducing ethylene to maintain the relative stability of the pressure in the reaction kettle;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to room temperature of 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The properties of the resin powder special for chlorinated polyethylene obtained in example 5 are as follows: the density was 0.955g/cm3,MFR5kg1.3g/10min, and a bulk density of 0.4g/cm3The wax content was 0.23%, the S value was 17, and the average particle diameter was 252 μm.
Example 6
Example 6 a resin powder for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is n-hexane, and the stirring speed is 500 rpm.
(2) Adding hydrogen and alpha-olefin into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.02, and the molar ratio of the alpha-olefin to the ethylene is 0.01; wherein the alpha-olefin is butene-1
(3) Introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.80 MPa;
(4) adding an antimony modified supported chromium catalyst and a cocatalyst into a slurry reaction kettle to perform slurry polymerization reaction (wherein the dosage of the antimony modified supported chromium catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triisobutylaluminum), and reacting for 3 hours; in the polymerization reaction process, introducing ethylene to maintain the relative stability of the pressure in the reaction kettle, and reacting ethylene in total 492 g;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to room temperature of 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The properties of the resin powder for chlorinated polyethylene obtained in example 6 were as follows: the density was 0.956g/cm3,MFR5kg1.3g/10min, and a bulk density of 0.39g/cm3The wax content was 0.25%, the S value was 18, and the average particle diameter was 253. mu.m.
Example 7
Example 7a resin powder for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is n-hexane, and the stirring speed is 500 rpm.
(2) Adding hydrogen and alpha-olefin into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.02, and the molar ratio of the alpha-olefin to the ethylene is 0.01; wherein the alpha-olefin is butene-1
(3) Introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.80 MPa;
(4) adding an antimony modified supported chromium catalyst and a cocatalyst into a slurry reaction kettle to perform slurry polymerization reaction (wherein the dosage of the antimony modified supported chromium catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triisobutylaluminum), and reacting for 3 hours; in the polymerization reaction process, 266g of ethylene is reacted together by introducing the ethylene to maintain the relative stability of the pressure in the reaction kettle;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to room temperature of 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
Examples7 the properties of the special resin powder for chlorinated polyethylene obtained are as follows: the density is 0.954g/cm3,MFR5kg2g/10min, and a bulk density of 0.39g/cm3The wax content was 0.32%, the S value was 28, and the average particle diameter was 251 μm.
Example 8
Example 8 a resin powder for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is n-hexane, and the stirring speed is 500 rpm.
(2) Adding hydrogen and alpha-olefin into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.02, and the molar ratio of the alpha-olefin to the ethylene is 0.01; wherein the alpha-olefin is butene-1
(3) Introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.80 MPa;
(4) adding an antimony modified supported chromium catalyst and a cocatalyst into a slurry reaction kettle to perform slurry polymerization reaction (wherein the dosage of the antimony modified supported chromium catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triisobutylaluminum), and reacting for 3 hours; in the polymerization reaction process, introducing ethylene to maintain the relative stability of the pressure in the reaction kettle, and reacting 107g of ethylene;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to room temperature of 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The properties of the resin powder for chlorinated polyethylene obtained in example 8 were as follows: the density is 0.954g/cm3,MFR5kg3.1g/10min, and a bulk density of 0.4g/cm3The wax content was 0.51%, the S value was 31, and the average particle diameter was 247 μm.
The antimony modified supported chromium catalysts used in examples 5-8 were prepared as follows:
a) fully mixing a supported chromium catalyst and an antimony compound, and then placing the mixture in a tubular furnace, wherein the supported chromium catalyst is Advent C, and the antimony compound is antimony trioxide. The temperature was raised to 500 ℃ at 10 ℃/min under a nitrogen atmosphere (flow rate 50mL/min) and maintained for 3 hours. Then roasting in nitrogen atmosphere at 600 ℃ for 5h, and then naturally cooling to obtain the precursor.
b) And c) carrying out reduction reaction on the precursor obtained in the step a) in the presence of an organic metal reducing agent under the nitrogen atmosphere, and drying the obtained reduction product to obtain the antimony element modified supported chromium catalyst. Wherein the organic metal reducing agent is ethoxy diethyl aluminum, the reduction temperature of the reduction reaction is 20 ℃, the reduction time is 1 hour, and the molar ratio of aluminum to chromium is 40 based on the aluminum element in the organic metal reducing agent and the chromium element in the supported chromium catalyst.
In the obtained antimony element-modified supported chromium-based catalyst, the amounts of antimony element supported in examples 5 to 8 were 0.01 wt%, 0.02 wt%, 1 wt%, and 5 wt%, in that order, based on the total weight of the antimony element-modified supported chromium-based catalyst, and the average particle diameter was 14 μm.
Comparative example 1
Comparative example 1 a resin powder for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is normal hexane, and the stirring speed is 500 rpm;
(2) adding hydrogen into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.04;
(3) introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.75 MPa;
(4) 20mg of Ziegler-Natta catalyst (Avant Z501) is added into the slurry reactor, and the gas phase components are discharged after 1.5 hours of reaction; in the polymerization reaction process, 517g of ethylene is reacted together by introducing the ethylene to maintain the relative stability of the pressure in the reaction kettle;
(5) hydrogen and alpha-olefin were fed back to the slurry reactor at a hydrogen to ethylene molar ratio of 2.5 and an alpha-olefin to ethylene molar ratio of 0.04. Wherein the alpha-olefin is butene-1;
(6) introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.25MPa for 1.5 hours; in the polymerization reaction process, the pressure in the reaction kettle is kept relatively stable through the introduction of ethylene;
(7) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to 20 ℃ by reactor jacket water;
(8) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The properties of the resin powder special for chlorinated polyethylene obtained in comparative example 1 were as follows: the density is 0.954g/cm3,MFR5kg2.6g/10min, and a bulk density of 0.39g/cm3The wax content was 2.73%, the S value was 27, and the average particle diameter was 367 μm.
COMPARATIVE EXAMPLE 2 (COMPARATIVE WITH EXAMPLE 2)
Comparative example 2 the resin powder special for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is n-hexane, and the stirring speed is 500 rpm.
(2) Adding hydrogen and alpha-olefin into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.02, and the molar ratio of the alpha-olefin to the ethylene is 0.01; wherein the alpha-olefin is butene-1.
(3) Introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.85 MPa;
(4) adding a Metallocene catalyst XCAT Metallocene cocatalyst (manufacturer Univation) into a slurry reaction kettle to perform slurry polymerization reaction (wherein the dosage of the Metallocene catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triisobutylaluminum), and reacting for 3 hours; in the polymerization reaction process, the pressure in the reaction kettle is kept relatively stable by introducing ethylene, and 590g of ethylene is reacted;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The properties of the resin powder special for chlorinated polyethylene obtained in comparative example 2 were as follows: the density was 0.956g/cm3,MFR5kg1.7g/10min, and a bulk density of 0.41g/cm3The wax content was 1.06%, the S value was 8, and the average particle diameter was 220 μm.
COMPARATIVE EXAMPLE 3 (COMPARATIVE WITH EXAMPLE 2)
Comparative example 3 the resin powder special for chlorinated polyethylene was prepared according to the following process steps:
(1) adding alkane solvent into a slurry reaction kettle, starting continuous stirring, and heating the reaction kettle to 80 ℃; wherein the alkane solvent is n-hexane, and the stirring speed is 500 rpm.
(2) Adding hydrogen and alpha-olefin into the slurry reactor, wherein the molar ratio of the hydrogen to the ethylene is 0.02, and the molar ratio of the alpha-olefin to the ethylene is 0.01; wherein the alpha-olefin is butene-1.
(3) Introducing ethylene into the slurry reaction kettle, and enabling the reaction pressure in the slurry reaction kettle to reach 0.85 MPa;
(4) adding a chromium-based catalyst Advent C and a cocatalyst into a slurry reaction kettle to perform a slurry polymerization reaction (wherein the dosage of the chromium-based catalyst is 20mg, the dosage of the cocatalyst is 3mL, and the cocatalyst is triisobutylaluminum), and reacting for 3 hours; in the polymerization reaction process, introducing ethylene to maintain the relative stability of the pressure in the reaction kettle, and reacting 503g of ethylene;
(5) venting the pressure in the slurry reactor and reducing the temperature of the materials in the slurry reactor to 20 ℃ by reactor jacket water;
(6) and (3) discharging the slurry of the polymerization reactant from the bottom of the slurry reaction kettle, and carrying out flash evaporation, centrifugation and drying to obtain the special resin powder for the chlorinated polyethylene.
The properties of the resin powder special for chlorinated polyethylene obtained in comparative example 3 were as follows: the density was 0.957g/cm3,MFR5kg1.4g/10min, and a bulk density of 0.40g/cm3The wax content was 0.27%, the S value was 8, and the average particle diameter was 249 μm.
Example 9
The chlorinated polyethylene special resin obtained in the above examples and comparative examples is prepared by the following steps:
5L of water and 500g of the special resin for the chlorinated polyethylene prepared in the above example or comparative example are added into a reactor, a dispersant, an emulsifier and an initiator are added into the reactor, and chlorination is carried out for 3 hours at 130 ℃ in gaseous chlorine (excess chlorine), so as to obtain chlorinated polyethylene samples 1-11 respectively, and the performances are as shown in the following table. In the table, samples 1 to 11 correspond to chlorinated polyethylene samples prepared by carrying out reactions using the chlorinated polyethylene exclusive resins of example 1, example 2, example 3, example 4, example 5, example 6, example 7, example 8, comparative example 1, comparative example 2, and comparative example 3 in this order.
Wherein, the used dispersant is sodium polymethacrylate, the emulsifier is polyvinylpyrrolidone, and the initiator is dibenzoyl peroxide; the dosage of the three components is 14g, 1g and 4g respectively.
Table: chlorinated polyethylene Performance test results
From the results in table 6, it can be seen that the chlorinated polyethylene prepared based on the resins special for chlorinated polyethylene of examples 1 to 8 of the present invention has higher chlorine content and better tensile strength in the same chlorination conditions, which indicates that the chlorinated polyethylene produced has fast chlorination rate, uniform chlorine distribution and excellent production efficiency and stability.
From the results in table 6, it can be seen that the chlorinated polyethylene obtained by chlorinating the resin special for chlorinated polyethylene of the present invention shows good mooney viscosity and excellent tensile strength, and the obtained product can well give consideration to both processability and mechanical properties of chlorinated polyethylene, and has good application prospects.
It will be appreciated by those skilled in the art that modifications or adaptations to the invention may be made in light of the teachings of the present specification. Such modifications or adaptations are intended to be within the scope of the present invention as defined in the claims.