A polyolefin nucleating agent compound and preparation method thereof

Abstract

The present invention relates to the technical field of nucleating agents, and in particular to a polyolefin nucleating agent compound and a preparation method thereof. The polyolefin nucleating agent compound comprises the following components: an organic carrier, a modified inorganic nucleating agent, and a phosphate nucleating agent, wherein the organic carrier is selected from a GMA-grafted polyolefin elastomer and a cycloolefin copolymer. When the polyolefin nucleating agent compound in the invention is used, the polyolefin product not only has excellent light transmittance, but also has excellent stress whitening resistance.

Description

Technical Field

[0001] The invention relates to the technical field of nucleating agents, and in particular to a polyolefin nucleating agent compound and a preparation method thereof. Background Art

[0002] Phosphate nucleating agents play an important role in polyolefin processing. Their core function is to optimize the physical properties of polymers. Compared with traditional DBS nucleating transparent agents, phosphate nucleating agents can show excellent transparency-enhancing effects at low concentrations, and have good extraction resistance and no odor, which gives them unique advantages in the field of polymer modification.

[0003] However, despite the many advantages of phosphate nucleating agents, attention should still be paid to their operational safety during use. Since most phosphate nucleating agents are in powder form, they should avoid dust formation during operation and use, and should be kept away from fire sources to prevent possible safety risks; and their compatibility with polyolefins is poor. When these two nucleating agents are used alone, they have certain limitations in terms of rigidity, transparency and heat resistance of polyolefins; and these nucleating agents have too high a melting point, poor dispersibility, and limited compatibility with resins. Summary of the invention

[0004] The object of the present invention is to provide a polyolefin nucleating agent compound and a preparation method thereof. The polyolefin nucleating agent compound has good compatibility with polyolefins and has a granular appearance, which can avoid the safety risks of powders.

[0005] To achieve the above-mentioned purpose, the first aspect of the present invention provides a polyolefin nucleating agent compound, which comprises the following components: an organic carrier, a modified inorganic nucleating agent, and a phosphate nucleating agent, wherein the organic carrier is selected from a GMA-grafted polyolefin elastomer and a cycloolefin copolymer; and the modified inorganic nucleating agent is a polyoxyethylene stearate-modified inorganic nucleating agent.

[0006] When the polyolefin nucleating agent compound of the present invention is used, the polyolefin product not only has excellent light transmittance, but also has excellent stress whitening resistance. This may be because the modified inorganic nucleating agent and the phosphate nucleating agent are dispersed in the organic carrier, so that the compound can be better dispersed in the polyolefin system, especially the polypropylene system, when used, and the modified inorganic nucleating agent and the phosphate nucleating agent synergistically act with each other, so that the polypropylene spherulites cannot be nucleated and grown by the modified inorganic nucleating agent and the phosphate nucleating agent, thereby refining the size of the crystal, thereby better increasing the light transmittance of the product. On the other hand, this may be because the GMA grafted polyolefin elastomer and the cycloolefin copolymer interact with the polyolefin, especially the block polypropylene, which can promote the specific structure inside the polyolefin to absorb the external impact energy faster when subjected to external force impact, and slow down or prevent the stress whitening phenomenon of the block polypropylene resin.

[0007] As a preferred technical solution of the present invention, in the polyolefin nucleating agent compound, the mass ratio of the modified inorganic nucleating agent to the organic carrier is (10-30):100, preferably (15-20):100.

[0008] As a preferred technical solution of the present invention, in the polyolefin nucleating agent compound, the mass ratio of the phosphate nucleating agent to the organic carrier is (15-40):100, preferably (25-30):100.

[0009] In the present invention, by controlling the mass ratio of the organic carrier, the modified inorganic nucleating agent and the phosphate nucleating agent in the polyolefin nucleating agent compound, the polyolefin nucleating agent compound can be better increased when used for polyolefins, especially block polypropylene, and can better increase the light transmittance and stress whitening resistance of the product.

[0010] The organic carrier of the present invention refers to a carrier that carries a modified inorganic nucleating agent and a phosphate nucleating agent, and the modified inorganic nucleating agent and the phosphate nucleating agent are dispersed in the organic carrier. In order to better increase the performance of the polyolefin nucleating agent compound, as a preferred technical solution of the present invention, the mass ratio of the GMA grafted polyolefin elastomer to the cycloolefin copolymer is 1: (2-20), for example, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:13, 1:15, 1:18, 1:20, preferably 1: (5-15), and more preferably 1: (5-10).

[0011] In the present invention, by controlling the GMA grafted polyolefin elastomer and the cycloolefin copolymer, the polyolefin nucleating agent compound can better increase the light transmittance and stress whitening resistance of the product.

[0012] In the present invention, the GMA-grafted polyolefin elastomer refers to glycidyl methacrylate (GMA) being grafted onto the macromolecular chain of the polyolefin elastomer. As a preferred technical solution of the present invention, the GMA-grafted polyolefin elastomer is GMA-grafted POE.

[0013] As a more preferred technical solution of the present invention, the melt index of the GMA-grafted POE at 190° C. and 2.16 kg is 1.5-5.5 g / 10 min, preferably 1.5-2.5 g / 10 min.

[0014] The GMA-grafted POE in the present invention can be obtained commercially, for example, from Shenyang Ketong Plastic Co., Ltd., with the brand name KT-33.

[0015] In the present invention, the cycloolefin copolymer is prepared by polymerization of cycloolefin monomer and other monomers, and has excellent low water absorption and high dimensional stability. In the present invention, the cycloolefin copolymer and the GMA grafted polyolefin elastomer work together to make the polyolefin nucleating agent compound better increase the light transmittance and stress whitening resistance of the product when used. This may be because the cycloolefin copolymer is amorphous, and it and the GMA grafted polyolefin elastomer are used together as organic carriers, which can not only increase the dispersibility of the modified inorganic nucleating agent and the phosphate nucleating agent in the polyolefin system, but also will not affect the performance of the modified inorganic nucleating agent and the phosphate nucleating agent when preparing the polyolefin nucleating agent compound. As a preferred technical solution of the present invention, the melt flow rate of the cycloolefin copolymer at 190°C / 2.16 kg is 1-5g / 10 min, preferably 1-3 g / 10 min, and more preferably 2.7 g / 10 min.

[0016] The cyclic olefin copolymer in the present invention can be obtained from the market, for example, it is TOPAS® Elastomer E-140 of German TOPAS.

[0017] In the present invention, under the support of an organic carrier, the polyoxyethylene stearate modified inorganic nucleating agent and the nucleating agent phosphate salt nucleating agent can better synergize, so that the polyolefin nucleating agent compound can better increase the light transmittance and stress whitening resistance of the polyolefin when used for the polyolefin.

[0018] As a more preferred technical solution of the present invention, the preparation method of the modified inorganic nucleating agent comprises:

[0019] (1) mixing an inorganic nucleating agent with water to obtain a first mixed solution;

[0020] (2) Adding polyoxyethylene stearate to the first mixed solution at 55-65° C. and stirring for 3-5 hours, followed by spray drying to obtain a modified inorganic nucleating agent.

[0021] In the present invention, when an unmodified inorganic nucleating agent is used, the polyolefin nucleating agent compound can increase the light transmittance and stress whitening resistance of the polyolefin when used in the polyolefin product. However, when the polyolefin product is a film product, it will be stuck during high-temperature cooking. This may be because the inorganic nucleating agent, especially the surface of silica and tetrapod-shaped zinc oxide whiskers, has some small molecular hydroxyl groups. It may also be because the presence of GMA in the GMA-grafted polyolefin elastomer reduces the moisture and heat resistance of the polyolefin product. In the present invention, the oxygen hydroxyl groups on the surface of silica and tetrapod-shaped zinc oxide whiskers may react with the polyoxyethylene. The oxygen atoms in ethylene stearate have hydrogen bonding effect to form physical adsorption, and the hydroxyl groups on the surface of silica and tetrapod-shaped zinc oxide whiskers may also chemically condense with polyoxyethylene stearate to form chemical grafting, so that the modified inorganic nucleating agent and GMA in the GMA-grafted polyolefin elastomer can produce hydrogen bonding adsorption or chemical condensation, so that the modified inorganic nucleating agent can be well dispersed in the organic carrier, and the polyolefin nucleating agent compound has excellent moisture and heat resistance. When the polyolefin nucleating agent compound is used in polyolefin film products, it can be evenly distributed in the film to obtain a uniform anti-adhesion film.

[0022] In the present invention, when preparing the modified inorganic nucleating agent, the mass ratio of the inorganic nucleating agent to water is (1-20):100, preferably (10-15):100.

[0023] In the present invention, when preparing the modified inorganic nucleating agent, the mass ratio of the inorganic nucleating agent to polyoxyethylene stearate is 1:(1-2), for example, 1:1, 1:1.1, 1:1.2, 1:1.5, 1:1.8, 1:2.

[0024] As a preferred technical solution of the present invention, the inorganic nucleating agent in the modified inorganic nucleating agent, i.e., the inorganic nucleating agent in step (1) is selected from at least one of tetrapod-shaped zinc oxide whiskers, organic montmorillonite, silicon dioxide and magnesium oxide whiskers.

[0025] As a more preferred technical solution of the present invention, the inorganic nucleating agent is selected from silicon dioxide and tetrapod-shaped zinc oxide whiskers, especially a mass ratio of 1: (1-5), for example, 1: 1, 1: 1.4, 1: 1.6, 1: 2, 1: 3, 1: 4, 1: 5, preferably 1: (1-3), more preferably 1: (1.4-2).

[0026] In the present invention, the inventors found that when the inorganic nucleating agents are silica and tetrapod-shaped zinc oxide whiskers, the polyolefin nucleating agent compound can better increase the light transmittance of the polyolefin product when used for polyolefin. On the one hand, this may be because when the modified silica and tetrapod-shaped zinc oxide whiskers are carried in an organic carrier, the modified inorganic nucleating agent and the polyolefin have better compatibility, which reduces the generation of void structures around the modified inorganic nucleating agent in the molding process, ensuring that light can better penetrate the product. On the other hand, this may be because silica and tetrapod-shaped zinc oxide whiskers have different microstructures, and the synergistic effect of the two allows the modified inorganic nucleating agent to spread in the polyolefin, which can improve the light transmittance of the product.

[0027] As a preferred technical solution of the present invention, the specific surface area of ​​the silicon dioxide is 100-400 m 2 / g, preferably 120-200 m 2 / g.

[0028] The silicon dioxide in the present invention can be obtained from the market, for example, its brand is WACKER HDK® HDK V15, and its specific surface area is 150±20 m 2 / g.

[0029] As a preferred technical solution of the present invention, the diameter of the four-needle zinc oxide whisker ranges from 0.5 to 5 um, and the length ranges from 10 to 50 um.

[0030] The four-needle zinc oxide whisker in the present invention can be obtained commercially, for example, from Qinghe County Chaotai Metal Materials Co., Ltd.

[0031] In the present invention, when preparing the modified inorganic nucleating agent, there is no special restriction on the mixing in step (1), as long as the inorganic nucleating agent and water are mixed evenly, for example, stirring at a speed of 200-400 rpm for 30-60 minutes.

[0032] In the present invention, when preparing the modified inorganic nucleating agent, the stirring speed in step (2) is 200-400 rpm.

[0033] In the present invention, when preparing the modified inorganic nucleating agent, the spray drying conditions in step (2) are not particularly limited and can be conventional conditions in the art. As a preferred technical solution of the present invention, the spray drying conditions include: an inlet air temperature of 160-200°C and an outlet air temperature of 100-120°C.

[0034] As a preferred technical solution of the present invention, the polyoxyethylene stearate is selected from at least one of polyoxyethylene (6) stearate, polyoxyethylene (9) stearate, polyoxyethylene (10) stearate, polyoxyethylene (12) stearate, polyoxyethylene (20) stearate and polyoxyethylene (40) stearate, preferably polyoxyethylene (12) stearate and / or polyoxyethylene (20) stearate.

[0035] As a preferred technical solution of the present invention, the phosphate salt nucleating agent is selected from at least one of tri-p-tolyl phosphate, triphenyl phosphate, di[2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate]hydroxyaluminum salt and 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt, preferably 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt.

[0036] The second aspect of the present invention provides a method for preparing the polyolefin nucleating agent compound of the present invention, the preparation method comprising:

[0037] S1 premixing an organic carrier, a modified inorganic nucleating agent and a phosphate nucleating agent to obtain a premix;

[0038] S2 extrude the premix in a twin-screw extruder, draw strands, pass water and cut into pellets.

[0039] In the present invention, the premixing conditions are not particularly limited, for example, mixing at room temperature and 200-400 rpm for 3-5 minutes.

[0040] In the present invention, the twin-screw extruder may be a conventional twin-screw extruder in the art, for example, with a length-to-diameter ratio of 40:1 and a screw diameter of 35 mm.

[0041] As a preferred technical solution of the present invention, the conditions for extrusion granulation include: a screw speed of 300-400 rpm; a temperature of each section of the extruder of 170-205°C. For example, the screw temperature of the twin-screw extruder during extrusion is divided into 6 sections in sequence, and the temperature of zone 1 is set to 170-175°C, zone 2 to 178-182°C, zone 3 to 185-190°C, zone 4 to 195-200°C, zone 5 to 195-200°C, and zone 6 to 203-205°C.

[0042] In the present invention, the size of the pellets is generally selected according to the needs, and is generally 1-3 mm.

[0043] When the polyolefin nucleating agent compound of the present invention is used for polyolefin, its usage amount is generally 0.1-5 wt %, preferably 0.5-2 wt %, of the mass of the polyolefin.

[0044] In the present invention, the polyolefin nucleating agent compound refers to a nucleating agent compound for polyolefin, and the polyolefin may be at least one of polyethylene, polypropylene and polybutylene, preferably polypropylene.

[0045] Compared with the prior art, the present invention has at least the following beneficial effects:

[0046] (1) The existing phosphate nucleating agents are in powder form, while the polyolefin nucleating agent compound of the present invention is in particle form, which is safer in use.

[0047] (2) When the polyolefin nucleating agent compound of the present invention is used, the polyolefin product not only has excellent light transmittance, but also has excellent stress whitening resistance. DETAILED DESCRIPTION

[0048] The present invention is described in detail below through examples. The following examples are only illustrative of the specific technical solutions of the present invention and do not limit the scope of the present invention. That is, it should be understood that non-essential simple corrections, adjustments and combinations made by those skilled in the art based on the inventive concept of the present invention are all within the scope of protection claimed by the present invention.

[0049] In the following examples and comparative examples, the silica grade is WACKER HDK® HDK V15 and its specific surface area is 150±20 m 2 / g; four-needle zinc oxide whiskers were purchased from Qinghe Chaotai Metal Materials Co., Ltd., with a diameter range of 0.5-5um and a length range of 10-50um; GMA-grafted POE was purchased from Shenyang Ketong Plastic Co., Ltd. with a brand name of KT-33; the brand name of cycloolefin copolymer was TOPAS® Elastomer E-140 from TOPAS of Germany. Unless otherwise specified, all raw materials can be obtained commercially.

[0050] Example 1

[0051] Preparation of modified inorganic nucleating agent

[0052] (1) preparing silicon dioxide, tetrapod-shaped oxide whiskers, polyoxyethylene (12) stearate and water in a mass ratio of 5:10:18:100;

[0053] (2) stirring silicon dioxide, tetrapod-shaped oxide whiskers and water at 400 rpm for 50 minutes to obtain a first mixed solution;

[0054] (3) Adding polyoxyethylene (12) stearate to the first mixed solution at 60°C, stirring and reacting for 4 hours, and then spray drying to obtain a modified inorganic nucleating agent. The spray drying conditions are: inlet air temperature is 180°C, and outlet air temperature is 105°C.

[0055] Preparation of polyolefin nucleating agent compound:

[0056] S1. Mix 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt, modified inorganic nucleating agent, GMA grafted polyolefin elastomer, and cycloolefin copolymer in a mass ratio of 30:15:10:90 at room temperature and 300 rpm for 4 minutes to obtain a premix;

[0057] S2 The premix is ​​extruded in a twin-screw extruder with a length-to-diameter ratio of 40:1 and a screw diameter of 35 mm (the screw temperature of the twin-screw extruder is divided into 6 sections during extrusion, with the temperature of zone 1 set to 170°C, zone 2 to 178°C, zone 3 to 188°C, zone 4 to 195°C, zone 5 to 197°C, and zone 6 to 205°C), and the strands are water-dried and pelletized to obtain a polyolefin nucleating agent compound with a particle size of 2 mm.

[0058] Example 2

[0059] Preparation of modified inorganic nucleating agent

[0060] (1) preparing silicon dioxide, tetrapod-shaped oxide whiskers, polyoxyethylene (20) stearate and water in a mass ratio of 6:10:24:100;

[0061] (2) stirring silicon dioxide, tetrapod-shaped oxide whiskers and water at 300 rpm for 60 minutes to obtain a first mixed solution;

[0062] (3) Adding polyoxyethylene (20) stearate to the first mixed solution at 65°C, stirring and reacting for 3 hours, and then spray drying to obtain a modified inorganic nucleating agent. The spray drying conditions are: inlet air temperature is 180°C, and outlet air temperature is 105°C.

[0063] Preparation of polyolefin nucleating agent compound:

[0064] S1. Mix 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt, modified inorganic nucleating agent, GMA grafted polyolefin elastomer, and cycloolefin copolymer in a mass ratio of 25:16:12:88 at room temperature and 300 rpm for 5 minutes to obtain a premix;

[0065] S2 The premix is ​​extruded in a twin-screw extruder with a length-to-diameter ratio of 40:1 and a screw diameter of 35 mm (the screw temperature of the twin-screw extruder is divided into 6 sections during extrusion, with the temperature of zone 1 set to 172°C, zone 2 to 180°C, zone 3 to 185°C, zone 4 to 200°C, zone 5 to 200°C, and zone 6 to 205°C), and the strands are water-dried and pelletized to obtain a polyolefin nucleating agent compound with a particle size of 2 mm.

[0066] Example 3

[0067] Preparation of modified inorganic nucleating agent

[0068] (1) Prepare silica, tetrapod-shaped oxide whiskers, polyoxyethylene (12) stearate and water in a mass ratio of 7:10:17:100.

[0069] (2) stirring silicon dioxide, tetrapod-shaped oxide whiskers and water at a speed of 400 rpm for 470 minutes to obtain a first mixed solution;

[0070] (3) Adding polyoxyethylene (12) stearate to the first mixed solution at 55°C and stirring for reaction for 5 hours, followed by spray drying to obtain a modified inorganic nucleating agent. The spray drying conditions are: inlet air temperature of 160°C and outlet air temperature of 110°C.

[0071] Preparation of polyolefin nucleating agent compound:

[0072] S1. Mix 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt, modified inorganic nucleating agent, GMA grafted polyolefin elastomer, and cycloolefin copolymer in a mass ratio of 25:20:15:85 at room temperature and 400 rpm for 3 minutes to obtain a premix;

[0073] S2 The premix is ​​extruded in a twin-screw extruder with a length-to-diameter ratio of 40:1 and a screw diameter of 35 mm (the screw temperature of the twin-screw extruder is divided into 6 sections during extrusion, with the temperature of zone 1 set to 172°C, zone 2 to 180°C, zone 3 to 190°C, zone 4 to 200°C, zone 5 to 200°C, and zone 6 to 205°C), and the strands are water-dried and pelletized to obtain a polyolefin nucleating agent compound with a particle size of 2 mm.

[0074] Example 4

[0075] Preparation of modified inorganic nucleating agent

[0076] (1) preparing tetrapod-shaped oxide whiskers, polyoxyethylene (20) stearate and water in a mass ratio of 16:24:100;

[0077] (2) stirring the tetrapod-shaped oxide whiskers and water at a speed of 300 rpm for 60 minutes to obtain a first mixed solution;

[0078] (3) Adding polyoxyethylene (20) stearate to the first mixed solution at 65°C, stirring and reacting for 3 hours, and then spray drying to obtain a modified inorganic nucleating agent. The spray drying conditions are: inlet air temperature is 180°C, and outlet air temperature is 105°C.

[0079] Preparation of polyolefin nucleating agent compound:

[0080] S1. Mix 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt, modified inorganic nucleating agent, GMA grafted polyolefin elastomer, and cycloolefin copolymer in a mass ratio of 25:16:12:88 at room temperature and 300 rpm for 5 minutes to obtain a premix;

[0081] S2 The premix is ​​extruded in a twin-screw extruder with a length-to-diameter ratio of 40:1 and a screw diameter of 35 mm (the screw temperature of the twin-screw extruder is divided into 6 sections during extrusion, with the temperature of zone 1 set to 172°C, zone 2 to 180°C, zone 3 to 185°C, zone 4 to 200°C, zone 5 to 200°C, and zone 6 to 205°C), and the strands are water-dried and pelletized to obtain a polyolefin nucleating agent compound with a particle size of 2 mm.

[0082] Example 5

[0083] Preparation of modified inorganic nucleating agent

[0084] (1) preparing silicon dioxide, polyoxyethylene (20) stearate and water in a mass ratio of 16:24:100;

[0085] (2) stirring silicon dioxide and water at a speed of 300 rpm for 60 minutes to obtain a first mixed solution;

[0086] (3) Adding polyoxyethylene (20) stearate to the first mixed solution at 65°C, stirring and reacting for 3 hours, and then spray drying to obtain a modified inorganic nucleating agent. The spray drying conditions are: inlet air temperature is 180°C, and outlet air temperature is 105°C.

[0087] Preparation of polyolefin nucleating agent compound:

[0088] S1. Mix 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt, modified inorganic nucleating agent, GMA grafted polyolefin elastomer, and cycloolefin copolymer in a mass ratio of 25:16:12:88 at room temperature and 300 rpm for 5 minutes to obtain a premix;

[0089] S2 The premix is ​​extruded in a twin-screw extruder with a length-to-diameter ratio of 40:1 and a screw diameter of 35 mm (the screw temperature of the twin-screw extruder is divided into 6 sections during extrusion, with the temperature of zone 1 set to 172°C, zone 2 to 180°C, zone 3 to 185°C, zone 4 to 200°C, zone 5 to 200°C, and zone 6 to 205°C), and the strands are water-dried and pelletized to obtain a polyolefin nucleating agent compound with a particle size of 2 mm.

[0090] Comparative Example 1

[0091] Preparation of polyolefin nucleating agent compound:

[0092] S1. Mix 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt, silicon dioxide, tetrapod-shaped oxide whisker, GMA-grafted polyolefin elastomer, and cycloolefin copolymer in a mass ratio of 25:6:10:12:88 at room temperature and 300 rpm for 5 minutes to obtain a premix;

[0093] S2 The premix is ​​extruded in a twin-screw extruder with a length-to-diameter ratio of 40:1 and a screw diameter of 35 mm (the screw temperature of the twin-screw extruder is divided into 6 sections during extrusion, with the temperature of zone 1 set to 172°C, zone 2 to 180°C, zone 3 to 185°C, zone 4 to 200°C, zone 5 to 200°C, and zone 6 to 205°C), and the strands are water-dried and pelletized to obtain a polyolefin nucleating agent compound with a particle size of 2 mm.

[0094] Comparative Example 2

[0095] Preparation of modified inorganic nucleating agent

[0096] (1) preparing silicon dioxide, tetrapod-shaped oxide whiskers, polyoxyethylene (20) stearate and water in a mass ratio of 6:10:24:100;

[0097] (2) stirring silicon dioxide, tetrapod-shaped oxide whiskers and water at 300 rpm for 60 minutes to obtain a first mixed solution;

[0098] (3) Adding polyoxyethylene (20) stearate to the first mixed solution at 65°C, stirring and reacting for 3 hours, and then spray drying to obtain a modified inorganic nucleating agent. The spray drying conditions are: inlet air temperature is 180°C, and outlet air temperature is 105°C.

[0099] Preparation of polyolefin nucleating agent compound:

[0100] S1. Mix 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt, modified inorganic nucleating agent, and cycloolefin copolymer in a mass ratio of 25:16:100 at room temperature and 300 rpm for 5 minutes to obtain a premix;

[0101] S2 The premix is ​​extruded in a twin-screw extruder with a length-to-diameter ratio of 40:1 and a screw diameter of 35 mm (the screw temperature of the twin-screw extruder is divided into 6 sections during extrusion, with the temperature of zone 1 set to 172°C, zone 2 to 180°C, zone 3 to 185°C, zone 4 to 200°C, zone 5 to 200°C, and zone 6 to 205°C), and the strands are water-dried and pelletized to obtain a polyolefin nucleating agent compound with a particle size of 2 mm.

[0102] Comparative Example 3

[0103] Preparation of modified inorganic nucleating agent

[0104] (1) preparing silicon dioxide, tetrapod-shaped oxide whiskers, polyoxyethylene (20) stearate and water in a mass ratio of 6:10:24:100;

[0105] (2) stirring silicon dioxide, tetrapod-shaped oxide whiskers and water at 300 rpm for 60 minutes to obtain a first mixed solution;

[0106] (3) Adding polyoxyethylene (20) stearate to the first mixed solution at 65°C, stirring and reacting for 3 hours, and then spray drying to obtain a modified inorganic nucleating agent. The spray drying conditions are: inlet air temperature is 180°C, and outlet air temperature is 105°C.

[0107] Preparation of polyolefin nucleating agent compound:

[0108] S1. Mix 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt, modified inorganic nucleating agent, and GMA grafted polyolefin elastomer in a mass ratio of 25:16:100 at room temperature and 300 rpm for 5 minutes to obtain a premix;

[0109] S2 The premix is ​​extruded in a twin-screw extruder with a length-to-diameter ratio of 40:1 and a screw diameter of 35 mm (the screw temperature of the twin-screw extruder is divided into 6 sections during extrusion, with the temperature of zone 1 set to 172°C, zone 2 to 180°C, zone 3 to 185°C, zone 4 to 200°C, zone 5 to 200°C, and zone 6 to 205°C), and the strands are water-dried and pelletized to obtain a polyolefin nucleating agent compound with a particle size of 2 mm.

[0110] Test Case

[0111] Preparation of polypropylene strips: Under the same conditions, a polypropylene base material (grade T36F) and a polyolefin nucleating agent compound (the polypropylene composite auxiliary agent in the embodiment and the comparative example, respectively), the mass of the polyolefin nucleating agent compound being 1wt% of the mass of the polypropylene base material, were mixed, melt-extruded using a twin-screw extruder at a barrel temperature of 200-230°C, and then injection-molded strips (100mm×3mm×3mm) were obtained using an injection molding machine.

[0112] Preparation of polypropylene film: The polypropylene strips were melted at 230°C, extruded into cast films, cooled on a cooling roller at 45°C to form a 0.85 mm cast film, and finally stretched under the same conditions to obtain a 25 μm polypropylene film.

[0113] 1. Anti-stickiness: Polypropylene material is made into a film with a thickness of 25μm

[0114] Two layers of polypropylene film were placed separately, and after being placed under 20kg pressure, 121°C, and 80% humidity for 3 hours, the two layers of polypropylene film products were observed to see whether they could be quickly separated: no adhesion was marked as A, slight adhesion was marked as B, and obvious adhesion was marked as C.

[0115] 2. Resistance to stress whitening: Bend the polypropylene strips 90° at the same force and speed, and observe the stress whitening phenomenon at the bending point: no whitening is recorded as A, slight whitening is recorded as B, and obvious whitening is recorded as C.

[0116] 3. Measure the light transmittance of polypropylene film according to GB / T2410.

[0117] The test results are shown in Table 1.

[0118] Table 1

[0119] Anti-stickiness Stress whitening resistance Light transmittance A A 94.6% A A 94.9% A A 94.8% B A 90.2% B B 87.5% C B 85.4% A B 87.2% C C 86.3%

[0120] It can be seen from the results in Table 1 that the nucleating agent compound of the present invention, when used for polyolefin, can better increase the stress whitening resistance and light transmittance of the polyolefin.

Claims

1. A polyolefin nucleating agent compound, characterized in that: The polyolefin nucleating agent compound comprises the following components: an organic carrier, a modified inorganic nucleating agent, and a phosphate nucleating agent, wherein the organic carrier is selected from a GMA grafted polyolefin elastomer and a cycloolefin copolymer; the modified inorganic nucleating agent is a polyoxyethylene stearate modified inorganic nucleating agent; The mass ratio of the GMA grafted polyolefin elastomer to the cycloolefin copolymer is 1:(2-20); the GMA grafted polyolefin elastomer is GMA grafted POE.

2. The polyolefin nucleating agent compound according to claim 1, characterized in that: In the polyolefin nucleating agent compound, the mass ratio of the modified inorganic nucleating agent to the organic carrier is (10-30):100; the mass ratio of the phosphate nucleating agent to the organic carrier is (15-40):

100.

3. The polyolefin nucleating agent compound according to claim 1, characterized in that: The GMA-grafted POE has a melt index of 1.5-5.5 g / 10 min at 190° C. and 2.16 kg.

4. The polyolefin nucleating agent compound according to any one of claims 1 to 3, characterized in that: The inorganic nucleating agent in the modified inorganic nucleating agent is selected from at least one of tetrapod-shaped zinc oxide whiskers, organic montmorillonite, silicon dioxide and magnesium oxide whiskers.

5. The polyolefin nucleating agent compound according to claim 4, characterized in that: The inorganic nucleating agent in the modified inorganic nucleating agent is selected from silicon dioxide and tetrapod-shaped zinc oxide whiskers.

6. The polyolefin nucleating agent compound according to claim 1, characterized in that: The phosphate salt nucleating agent is selected from at least one of tri-p-tolyl phosphate, triphenyl phosphate, di[2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate]hydroxyaluminum salt and 2,2'-methylene-bis(4,6-di-tert-butylphenyl) phosphate sodium salt.

7. The polyolefin nucleating agent compound according to claim 1, characterized in that: The polyoxyethylene stearate in the polyoxyethylene stearate-modified inorganic nucleating agent is selected from at least one of polyoxyethylene (6) stearate, polyoxyethylene (9) stearate, polyoxyethylene (10) stearate, polyoxyethylene (12) stearate, polyoxyethylene (20) stearate and polyoxyethylene (40) stearate.

8. A method for preparing the polyolefin nucleating agent compound according to any one of claims 1 to 7, characterized in that: The preparation method comprises: S1 premixing an organic carrier, a modified inorganic nucleating agent and a phosphate nucleating agent to obtain a premix; S2 extrude the premix in a twin-screw extruder, draw strands, pass water and cut into pellets.

9. The preparation method according to claim 8, characterized in that: The conditions for extrusion granulation include: the screw speed is 300-400 rpm; the temperature of each section of the extruder is 170-205°C.