Preparation method of high-flowing high ethylene content polypropylene randon transparent copolymer resin

Abstract

The invention relates to a preparation method of a high-flowing high ethylene content polypropylene randon transparent copolymer resin, characterized in that: a 4th Z-N catalyst is used, the ratio of triethyl aluminum flow to propylene flow is 0.1-0.30, the ratio of external electron donor flow to propylene flow is 0.04-0.2, the addition of ethylene in a single-loop polymerization reactor accounts for 30-50 % of the total amount of ethylene, the addition of ethylene in a dual-loop polymerization reactor accounts for 70-50 % of the total amount of ethylene, hydrogen concentrations of the two loop polymerization reactors are both 0.12-0.15 %, the melt flow rate of polymeric powder is controlled within 11-14 g / 10 min, the ethylene content is controlled within 3.6-4.0 %, a premix consisting of anti-oxidant, neutralizer and nucleating agent and rheological masterbatch are added and then extrusion granulation is carried out, and a final product has the melt flow rate of 16-18 g / 10 min, the ethylene content of 3.6-4.0 %, the hexane extract content of less than 1.6 %, and the haze of less than 10%.

Description

technical field

[0001] The invention relates to a preparation method of random copolymerized transparent polypropylene resin with high flow (flow rate 14-20g / 10min) and high ethylene content (ethylene content 3.6-4.0%), belonging to the field of synthetic resins. Background technique

[0002] In recent years, transparent polypropylene has developed rapidly and has been widely used in various aspects such as culture, medical treatment, and food packaging. It is developed in the direction of high transparency, high transparency and high mechanical properties.

[0003] The improvement of fluidity will reduce the impact toughness of the product. Therefore, it is necessary to increase the content of comonomer to compensate for the loss of toughness. However, due to the limitation of polymerization technology, the content of comonomer in random copolymerized transparent polypropylene is generally low. In addition, the increase of the comonomer will increase the solvent extraction...

Examples

Embodiment 1

[0028] The CS catalyst is added to the pre-contact tank D2201 at 120g / h, according to the ratio of triethylaluminum flow / propylene flow ratio of 0.14kg / kg, and external electron donor flow / propylene flow ratio of 0.1kg / kg, respectively. The complex formed by thorough stirring and mixing enters the online mixer Z2203 and mixes with cold propylene (6t / h), then flows into the pre-polymerization reactor R2200, reacts at 20°C and 3.4Mpa pressure for 4min, and then enters a loop polymerization reaction In the R2201, add ethylene and hydrogen at the same time, control the ethylene flow rate to 30% of the total flow rate, and the hydrogen concentration to be 0.13-0.15% (V / V). Enter the two-loop polymerization reactor, the reaction conditions of the two-loop polymerization reactor are the same as that of the ring, the ethylene flow rate is controlled to be 70% of the total flow rate, the hydrogen concentration is 0.13-0.15% (V / V), the reaction time is 0.6h, and the polymerization reacti...

Embodiment 2

[0030] The CS catalyst is added to the pre-contact tank D2201 at 120g / h, according to the ratio of triethylaluminum flow / propylene flow ratio of 0.2kg / kg and external electron donor flow / propylene flow ratio of 0.08kg / kg. The complex formed by thorough stirring and mixing enters the online mixer Z2203 and mixes with cold propylene (6t / h), then flows into the pre-polymerization reactor R2200, reacts at 20°C and 3.4Mpa pressure for 4min, and then enters a loop polymerization reaction In the R2201, add ethylene and hydrogen at the same time, control the flow rate of ethylene to be 50% of the total flow rate, and the concentration of hydrogen gas to be 0.12-0.15% (V / V). Enter the two-loop polymerization reactor, the reaction conditions of the two-loop polymerization reactor are the same as that of the ring, the ethylene flow rate is controlled to be 50% of the total flow rate, the hydrogen concentration is 0.12-0.15% (V / V), the reaction time is 0.6h, and the polymerization reaction...

technical field

[0001] The invention relates to a preparation method of random copolymerized transparent polypropylene resin with high flow (flow rate 14-20g / 10min) and high ethylene content (ethylene content 3.6-4.0%), belonging to the field of synthetic resins. Background technique

[0002] In recent years, transparent polypropylene has developed rapidly and has been widely used in various aspects such as culture, medical treatment, and food packaging. It is developed in the direction of high transparency, high transparency and high mechanical properties.

[0003] The improvement of fluidity will reduce the impact toughness of the product. Therefore, it is necessary to increase the content of comonomer to compensate for the loss of toughness. However, due to the limitation of polymerization technology, the content of comonomer in random copolymerized transparent polypropylene is generally low. In addition, the increase of the comonomer will increase the solvent extraction...

Examples

Embodiment 1

[0028] The CS catalyst is added to the pre-contact tank D2201 at 120g / h, according to the ratio of triethylaluminum flow / propylene flow ratio of 0.14kg / kg, and external electron donor flow / propylene flow ratio of 0.1kg / kg, respectively. The complex formed by thorough stirring and mixing enters the online mixer Z2203 and mixes with cold propylene (6t / h), then flows into the pre-polymerization reactor R2200, reacts at 20°C and 3.4Mpa pressure for 4min, and then enters a loop polymerization reaction In the R2201, add ethylene and hydrogen at the same time, control the ethylene flow rate to 30% of the total flow rate, and the hydrogen concentration to be 0.13-0.15% (V / V). Enter the two-loop polymerization reactor, the reaction conditions of the two-loop polymerization reactor are the same as that of the ring, the ethylene flow rate is controlled to be 70% of the total flow rate, the hydrogen concentration is 0.13-0.15% (V / V), the reaction time is 0.6h, and the polymerization reacti...

Embodiment 2

[0030] The CS catalyst is added to the pre-contact tank D2201 at 120g / h, according to the ratio of triethylaluminum flow / propylene flow ratio of 0.2kg / kg and external electron donor flow / propylene flow ratio of 0.08kg / kg. The complex formed by thorough stirring and mixing enters the online mixer Z2203 and mixes with cold propylene (6t / h), then flows into the pre-polymerization reactor R2200, reacts at 20°C and 3.4Mpa pressure for 4min, and then enters a loop polymerization reaction In the R2201, add ethylene and hydrogen at the same time, control the flow rate of ethylene to be 50% of the total flow rate, and the concentration of hydrogen gas to be 0.12-0.15% (V / V). Enter the two-loop polymerization reactor, the reaction conditions of the two-loop polymerization reactor are the same as that of the ring, the ethylene flow rate is controlled to be 50% of the total flow rate, the hydrogen concentration is 0.12-0.15% (V / V), the reaction time is 0.6h, and the polymerization reaction...

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