A polypropylene drawing masterbatch, its preparation method and application

Abstract

The present invention relates to the technical field of polypropylene masterbatches, and particularly relates to a polypropylene drawing masterbatch, a preparation method thereof, and an application thereof. The raw material composition of the polypropylene masterbatch provided by the present invention comprises polypropylene, calcium carbonate powder, a surface modifier, a lubricant, a dispersant, an antioxidant, and a toughening agent. The polypropylene drawing masterbatch provided by the present invention is plastified, dispersed, and extruded using a parallel triple screw to obtain the polypropylene drawing masterbatch. When the prepared polypropylene drawing masterbatch is applied to plastic woven products, the addition amount is high, and it has excellent dispersion effects and mechanical properties. When used as a modifier in the high-speed drawing process, it can increase the drawing speed, improve the glossiness of the flat yarn, reduce the precipitation of powder, reduce the carbon deposition on the die, enhance the mechanical properties of the polypropylene resin, and improve the elongation rate of the flat yarn.

Description

Technical Field

[0001] The present invention relates to the technical field of polypropylene masterbatches, and particularly relates to a polypropylene drawing masterbatch, a preparation method thereof, and an application thereof. Background Art

[0002] The drawing process can process plastic raw materials into filaments of various shapes, and further processed to obtain plastic woven products. During the drawing process, the faster the drawing speed, the higher the tensile force on the flat filaments. According to the rotational speed of the roller line, drawing can be divided into ordinary drawing and high-speed drawing. Among them, high-speed drawing refers to a drawing process with a roller line rotational speed ≥ 300 m / min, and the ordinary drawing speed is 200 - 300 m / min. The ordinary drawing speed is slow, the production efficiency is low, and the tensile force requirement for flat filaments is low.

[0003] In the drawing process, the plastic woven masterbatch is used as a modifier and plays an important role in plastic woven products. It is an indispensable raw and auxiliary material in plastic woven manufacturing. High-speed drawing uses conventional polypropylene raw materials for drawing, but has higher requirements for the drawing masterbatch. Generally, after adding an ordinary plastic woven masterbatch, although the raw material cost can be reduced to a certain extent, the mechanical properties of the material are reduced, and the tensile properties are insufficient when making flat filaments, resulting in broken filaments and the problem that the drawing speed cannot be increased. When the addition amount of the plastic woven masterbatch exceeds 20 wt%, the thermal stability of the flat filaments can be improved, the dimensional shrinkage can be reduced, the warping of the flat filaments can be reduced, and the flatness of the woven fabric can be improved. However, due to the low drawing speed of ordinary plastic weaving and the low requirements for the masterbatch, powders below 800 meshes are often used, and the powder content will exceed 90%. Generally, it can only be used to produce low-end products such as fertilizer bags and market bags. In 2022, the output of plastic filaments, ropes and woven products (referred to as plastic woven products) of enterprises above designated size in the country was about 14.53 million tons, of which about 1.2 million tons of masterbatch was used for plastic woven products. With the implementation of strict environmental protection requirements and the increasing demand for high-quality products from users, the use of inorganic powders will be further reduced, and the demand for more environmentally friendly filled masterbatches will be further increased.

[0004] Currently, inorganic powders are often used in combination with organic resins to prepare high-speed drawing masterbatches. However, inorganic powders and organic resins are incompatible, their binding ability is poor, and gaps are easily generated at the interface, resulting in a decrease in the mechanical properties of the material. Summary of the Invention

[0005] The purpose of the present invention is to provide a polypropylene drawing masterbatch, a preparation method thereof, and an application thereof, so as to improve the mechanical properties of polypropylene resin.

[0006] To achieve the above-mentioned invention purpose, the present invention provides the following technical solutions:

[0007] A polypropylene drawing masterbatch, comprising the following parts by mass of preparation raw materials:

[0008]

[0009] The particle size distribution of the calcium carbonate powder: D50 is 2.3 - 3.3 μm, D97 is 6.9 - 7.9 μm, and D100 is 8.7 - 9.7 μm;

[0010] The surface modifier contains maleic anhydride grafted polyethylene wax.

[0011] Optionally, the polypropylene contains at least one of the grades 045, 085, and T30S.

[0012] Optionally, in the calcium carbonate powder, the powder with a particle size ≤ 2 μm accounts for 32.2 - 33.2 wt%; the whiteness of the calcium carbonate powder is ≥ 98%, and the oil absorption value of the powder is 26 - 28 mL / 100 g.

[0013] Optionally, the lubricant contains at least one of stearic acid, polyethylene wax, Fischer-Tropsch wax, and paraffin wax.

[0014] Optionally, the dispersant contains at least one of metal stearates, ethylene bisstearamide, and monoglycerides.

[0015] Optionally, the antioxidant contains B215; the toughening agent contains at least one of POE, EVA, and maleic anhydride grafted polypropylene.

[0016] The present invention provides a method for preparing the polypropylene drawing masterbatch, comprising the following steps:

[0017] 1) Mix the calcium carbonate powder with the surface modifier and carry out co-blending modification to obtain modified calcium carbonate powder;

[0018] 2) Mix the modified calcium carbonate powder with the lubricant, dispersant, toughening agent, polypropylene, and antioxidant, and carry out pretreatment to obtain a pretreated material;

[0019] 3) Extrude the pretreated material using a parallel triple-screw extruder to obtain a polypropylene drawing masterbatch.

[0020] Optionally, in step 1), the rotation speed of the co-blending modification is 1500 - 1700 r / min, the temperature is 120 - 125 °C, and the time is 3 - 5 min;

[0021] In step 2), the mixing includes first mixing the modified calcium carbonate powder with the lubricant, dispersant, and toughening agent, and then mixing the obtained mixed material with the polypropylene and antioxidant for a second time;

[0022] The rotation speed of the first mixing is 1500 - 1700 r / min, the temperature is 105 - 120 °C, and the time is 2 - 4 min;

[0023] The rotation speed of the second mixing is 1500 - 1700 r / min, the temperature is 150 - 170 °C, and the time is 4 - 6 min.

[0024] Optionally, the feeding rotation speed of the extrusion in step 3) is 1000 - 1200 r / min, the heating temperature is 180 - 230 °C, the extrusion rotation speed is 1100 - 1500 r / min, and the main machine current of the extruder is 320 - 350 A.

[0025] The present invention also provides the application of the polypropylene drawing masterbatch as a modifier in plastic woven products.

[0026] In the polypropylene drawing masterbatch of the present invention, the calcium carbonate powder used as a filler is ultrafine calcium carbonate powder. The ultrafine calcium carbonate powder has a large specific surface area. Compared with low-mesh powder, the interfacial bonding area between the ultrafine calcium carbonate and the resin is large, which can enhance the mechanical properties of the polypropylene masterbatch. The present invention uses maleic anhydride grafted polyethylene wax as the surface modifier of the calcium carbonate powder and polypropylene resin as the carrier. The present invention selects lubricants and dispersants as processing aids and adopts a reasonable formula to maintain good dispersibility of the polypropylene drawing masterbatch while reducing the addition amount of processing aids and reducing the loss of the mechanical properties of the polypropylene drawing masterbatch by the aids.

[0027] The present invention uses a parallel three-screw extruder for plasticizing, dispersing and extruding to obtain the polypropylene drawing masterbatch. The parallel three-screw extruder has a large length-diameter ratio and high torque. The larger length-diameter ratio can improve the plasticizing and dispersing effect of the masterbatch, and the gearbox has a large torque and high output. In addition, the parallel three-screw extruder requires less processing lubricant and has a good plasticizing and dispersing effect, so as to reduce the addition amount of aids. Therefore, the preparation method of the polypropylene drawing masterbatch provided by the present invention has the characteristics of high output and low power consumption.

[0028] During the preparation process of plastic woven products, under the condition that the addition amount of the drawing masterbatch is the same (20 wt%), the polypropylene drawing masterbatch provided by the present invention can provide a higher drawing speed and mechanical properties. When it is used as a modifier in the high-speed drawing process of plastic woven products, it can improve the drawing speed, improve the gloss of the flat yarn, reduce the precipitation of powder, and reduce the carbon deposition at the die. Moreover, when preparing flat yarns with a normal drawing speed and having similar maximum drawing speed and mechanical properties, the addition amount of the polypropylene drawing masterbatch provided by the present invention is higher. Specific Embodiments

[0029] The present invention provides a polypropylene drawing masterbatch, which comprises the following raw materials for preparation in parts by mass:

[0030]

[0031] The particle size distribution of the calcium carbonate powder: D50 is 2.3 - 3.3 μm, D97 is 6.9 - 7.9 μm, and D100 is 8.7 - 9.7 μm;

[0032] The surface modifier contains maleic anhydride grafted polyethylene wax.

[0033] In the present invention, the mass parts of the polypropylene are preferably 36 - 43 parts, more preferably 38 - 42 parts, and even more preferably 39 - 40 parts; the polypropylene preferably contains at least one of the grades 045 (melt index of 4 g / 10 min), 085 (melt index of 8 g / 10 min), and T30S (melt index of 3 g / 10 min), and the polypropylene is preferably a polypropylene resin with different melt indexes (between 2 - 9 g / 10 min). When using more than one polypropylene, the ratio of the polypropylene is adjusted according to the melt flow rate of the formulation system and the pre-dispersion time of the high-speed stirred materials in a manner well-known in the art.

[0034] In the present invention, the mass parts of the calcium carbonate powder are preferably 290 - 315 parts, more preferably 295 - 310 parts, and even more preferably 300 - 305 parts; in the calcium carbonate powder, the powder with a particle size ≤ 2 μm accounts for 32.2 - 33.2 wt%; the whiteness of the calcium carbonate powder is ≥ 98%, and the oil absorption value of the powder is 26 - 28 mL / 100 g;

[0035] In the present invention, the preparation method of the calcium carbonate powder preferably includes the following steps:

[0036] (1) Select calcite with a calcium content ≥ 96 wt% as the raw ore, and perform rough crushing by an alligator crusher to obtain particles with a particle size of 2 - 5 cm;

[0037] (2) Convey the particles with a particle size of 2 - 5 to a ring-roll mill for grinding. The feeding speed is 30 kg / min, the main current of the ring-roll mill is 150 - 160 A, the current of the screening fan is 65 - 67 A, and the rotation speed of the primary classifier is 2100 r / min to obtain a primary classified calcium carbonate product;

[0038] (3) Classify the primary classified calcium carbonate product through a secondary classifier to obtain the calcium carbonate powder;

[0039] The particle size distribution of the primary classified calcium carbonate product is preferably: D50 is 2.8 ± 0.5 μm, D97 is 7.4 ± 0.5 μm, D100 is 11.5 ± 0.5 μm, and the content of ≤ 2 μm is 30.1 ± 0.5 wt%.

[0040] In the present invention, in the particle size distribution of the calcium carbonate powder, the D50 is preferably 2.4 - 3 μm, more preferably 2.5 - 2.93 μm, and even more preferably 2.8 - 2.85 μm;

[0041] In the particle size distribution of the calcium carbonate powder, the D97 is preferably 7.0 - 7.6 μm, more preferably 7.3 - 7.58 μm, and even more preferably 7.4 - 7.43 μm;

[0042] In the particle size distribution of the calcium carbonate powder, the D100 is preferably 8.9 - 9.4 μm, more preferably 9.0 - 9.37 μm, and even more preferably 9.2 - 9.28 μm;

[0043] In the particle size distribution of the calcium carbonate powder, the particle size of the powder accounting for 32.4 - 33 wt% is preferably ≤ 2 μm, more preferably the particle size of the powder accounting for 32.6 - 32.8 wt% is ≤ 2 μm, and even more preferably the particle size of the powder accounting for 32.68 - 32.74 wt% is ≤ 2 μm;

[0044] The whiteness of the calcium carbonate powder is preferably ≥ 98%, and the oil absorption value of the powder is preferably 26 - 28 mL / 100 g, more preferably 26 - 27 mL / 100 g.

[0045] The calcium carbonate powder in the present invention is obtained by taking calcite with a calcium content ≥ 96 wt% as the raw ore and using a ring roll mill equipment for secondary classification; the calcite has high purity and low impurity content, and the powder obtained by passing through the ring roll mill and undergoing secondary classification has uniform particle size and narrow distribution, and can better improve the mechanical properties of the masterbatch when applied to polypropylene high-speed drawing masterbatch.

[0046] In the present invention, the mass fraction of the surface modifier is preferably 1.1 - 1.75 parts, more preferably 1.25 - 1.6 parts, and even more preferably 1.4 - 1.5 parts; the surface modifier preferably contains maleic anhydride grafted polyethylene wax. Compared with traditional aluminate and titanate coupling agents, maleic anhydride grafted polyethylene wax has a higher molecular weight and a lower addition amount, and has a good enhancing effect on the tensile strength, processing fluidity, etc. of the system.

[0047] In the present invention, the mass fraction of the lubricant is preferably 6 - 7.5 parts, more preferably 6.5 - 7 parts; the lubricant preferably contains at least one of stearic acid, polyethylene wax, Fischer-Tropsch wax, and paraffin wax; preferably, the lubricant is prepared by compounding 3.5 parts of polyethylene wax, 1.5 parts of stearic acid, and 1 part of paraffin wax or by compounding 4 parts of polyethylene wax, 2 parts of stearic acid, and 2 parts of paraffin wax; the reasonable combination of lubricants can reduce the amount of lubricants used and reduce the influence of lubricants on the mechanical properties of the formulation system.

[0048] In the present invention, the mass fraction of the dispersant is preferably 2.5 to 3 parts; the dispersant preferably comprises at least one of stearate, ethylene bisstearamide, and monoglycerides; preferably 1 part of zinc stearate, 2 parts of ethylene bisstearamide or 1 part of ethylene bisstearamide and 1 part of monoglyceride; selecting a dispersant with a high flash point and low volatility can reduce the volatilization of the dispersant during twin-screw processing, improve the fluidity of powder dispersion processing, improve the demolding property of the masterbatch in downstream products, reduce carbon deposition at the die orifice, and improve the surface gloss of the product.

[0049] In the present invention, the antioxidant preferably comprises B215;

[0050] The mass fraction of the toughening agent is preferably 4 to 7 parts, more preferably 4 to 6 parts, and even more preferably 5 parts; the toughening agent preferably comprises at least one of POE, EVA, and maleic anhydride grafted polypropylene. When there are two or more of the above-mentioned toughening agents, the present invention has no special limitation on the ratio of different types of toughening agents, and any ratio is acceptable.

[0051] The present invention provides a method for preparing the polypropylene drawing masterbatch, comprising the following steps:

[0052] 1) Mix the calcium carbonate powder with a surface modifier and carry out co-blending modification to obtain modified calcium carbonate powder;

[0053] 2) Mix the modified calcium carbonate powder with a lubricant, a dispersant, a toughening agent, polypropylene, and an antioxidant, and carry out pretreatment to obtain a pretreated material;

[0054] 3) Extrude the pretreated material using a parallel triple-screw extruder to obtain a polypropylene drawing masterbatch.

[0055] In the present invention, for step 1), the rotation speed of the co-blending modification is preferably 1500 to 1700 r / min, more preferably 1500 to 1600 r / min, and even more preferably 1500 to 1550 r / min; the temperature is preferably 120 to 125 °C, more preferably 120 to 123 °C, and even more preferably 120 to 121 °C; the time is preferably 3 to 5 min, more preferably 4 to 5 min;

[0056] In the present invention, for step 1), the co-blending modification reaches the required temperature by means of heat transfer oil heating, and the heat transfer oil is preferably mineral heat transfer oil L-QB300;

[0057] For step 2), the mixing includes first mixing the modified calcium carbonate powder with a lubricant, a dispersant, and a toughening agent, and then mixing the obtained mixed material with polypropylene and an antioxidant;

[0058] The rotation speed of the first mixing is preferably 1500 - 1700 r / min, more preferably 1500 - 1600 r / min, and even more preferably 1500 - 1550 r / min; the temperature is preferably 105 - 120 °C, more preferably 110 - 115 °C; the time is preferably 2 - 4 min, more preferably 3 - 4 min;

[0059] The rotation speed of the second mixing is preferably 1500 - 1700 r / min, more preferably 1500 - 1600 r / min, and even more preferably 1500 - 1550 r / min; the temperature is preferably 150 - 170 °C, more preferably 155 - 170 °C, and even more preferably 160 - 165 °C; the time is preferably 4 - 6 min, more preferably 5 min.

[0060] In the present invention, step 2) is preferably when the current of the high - speed mixer reaches 250 - 280 A, more preferably 260 - 280 A; switch the rotation speed of the high - speed mixer to 900 r / min, and reduce the material temperature to 90 °C to discharge the pretreated material.

[0061] In the present invention, the screw diameter of the parallel triple - screw extruder is 73 mm, the screw length - to - diameter ratio is 56:1, the torque rating of the gearbox is 8.7, and it is equipped with a side - mounted high - speed forced feeder.

[0062] In the present invention, the feeding rotation speed of the extrusion in step 3) is preferably 1000 - 1200 r / min, more preferably 1050 - 1200 r / min, and even more preferably 1100 - 1200 r / min;

[0063] The heating temperature is preferably 180 - 230 °C, more preferably Zone 1: 190 - 230 °C, Zone 2: 190 - 230 °C, Zone 3: 190 - 230 °C, Zone 4: 190 - 230 °C, Zone 5: 190 - 210 °C, Zone 6: 190 - 210 °C, Zone 7: 180 - 200 °C, Zone 8: 180 - 200 °C, Zone 9: 180 - 200 °C, Zone 10: 180 - 200 °C, Zone 11: 180 - 200 °C, Zone 12: 180 - 200 °C, screen changer: 180 - 200 °C, die head: 180 - 200 °C; the extrusion rotation speed is preferably 1100 - 1500 r / min, more preferably 1100 - 1300 r / min, and even more preferably 1100 - 1200 r / min; the main motor current of the extruder is preferably 320 - 350 A, more preferably 330 - 340 A.

[0064] In the present invention, after extrusion by the extruder in step 3), it preferably sequentially includes pelletizing, water cooling, dehydration, screening and then entering the silo. After the masterbatch is detected to be qualified, it is packaged to obtain the finished polypropylene drawing masterbatch. The specific parameters of pelletizing, water cooling, dehydration and screening are determined according to the actual situation.

[0065] The present invention also provides the application of the prepared polypropylene drawing masterbatch in plastic woven products;

[0066] In the present invention, the application of the polypropylene drawing masterbatch includes the application as a modifier in high-speed drawing plastic woven products and the application in plastic woven products with ordinary drawing speed.

[0067] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0068] Example 1

[0069] The raw wollastonite ore is roughly broken and processed into ultrafine calcium carbonate powder by a ring-roll mill. The powder is screened by a secondary classifier. The particle size indexes of the screened calcium carbonate powder are: D50 is 2.85 μm, D97 is 7.43 μm, D100 is 9.28 μm, and the content of ≤2 μm is 32.74 wt%. The whiteness of the prepared calcium carbonate powder is 98%, and the oil absorption value of the powder is 26 mL / 100 g.

[0070] Take 300 parts of calcium carbonate powder and 1.5 parts of maleic anhydride grafted polyethylene wax and blend them in a high-speed mixer. The set rotation speed of the high-speed mixer is 1500 r / min, the temperature of the mineral type heat transfer oil L-QB300 is 120 °C, and blend for 5 min; keep the rotation speed of the high-speed mixer at 1500 r / min unchanged, add 6 parts of lubricants (including 3.5 parts of polyethylene wax, 1.5 parts of stearic acid, and 1 part of paraffin wax), 3 parts of dispersants (including 1 part of zinc stearate and 2 parts of ethylene bisstearamide), 4 parts of POE toughening agent, and mix at 120 °C for 4 min. Then add 40 parts of polypropylene resin (16 parts of 085 and 24 parts of T30S) and 0.1 part of antioxidant B215, and blend for 5 min until the material temperature reaches 170 °C. When the current of the high-speed mixer reaches 280 A, switch the rotation speed of the high-speed mixer to 900 r / min, and discharge the pretreated material until the material temperature drops to 90 °C;

[0071] The pretreated material is dispersed, plasticized and extruded through a parallel three-screw extruder. The heating temperatures of the extruder are set as follows: zone 1 at 210°C, zone 2 at 210°C, zone 3 at 210°C, zone 4 at 210°C, zone 5 at 195°C, zone 6 at 195°C, zone 7 at 190°C, zone 8 at 190°C, zone 9 at 185°C, zone 10 at 185°C, zone 11 at 185°C, zone 12 at 185°C, screen changer at 195°C, and die head at 195°C. The rotational speed of the extruder is 1100 r / min, the feeding rotational speed is 900 r / min, and the main motor current is 350 A. The material extruded from the extruder is pelletized, water-cooled, dehydrated, and screened, and then enters the storage bin. After passing the inspection, the masterbatch is packaged to obtain the polypropylene drawing masterbatch.

[0072] Example 2

[0073] The raw calcite ore is roughly broken and processed into ultrafine calcium carbonate powder by a ring-roll mill. The powder is screened by a secondary classifier. The particle size indexes of the screened calcium carbonate powder are as follows: D50 is 2.93 μm, D97 is 7.58 μm, D100 is 9.37 μm, and the content of ≤2 μm is 32.68 wt%. The prepared ultrafine calcium carbonate has a whiteness of 98% and an oil absorption value of 27 mL / 100 g.

[0074] Take 300 parts of calcium carbonate powder and 1.5 parts of maleic anhydride grafted polyethylene wax and blend them in a high-speed mixer. The set rotational speed of the high-speed mixer is 1500 r / min, the temperature of the mineral type heat transfer oil L-QB300 is 120°C, and blend for 3 min. Keep the rotational speed of the high-speed mixer at 1500 r / min unchanged, add 8 parts of lubricants (including 4 parts of polyethylene wax, 2 parts of stearic acid, and 2 parts of paraffin wax), 2 parts of dispersants (including 1 part of ethylene bisstearamide and 1 part of monoglyceride), 6 parts of POE toughening agent, and mix at 120°C for 3 min. Then add 38 parts of polypropylene resin 045 and 0.2 part of antioxidant B215, and blend for 4 min until the material temperature reaches 150°C. After the current of the high-speed mixer reaches 260 A, switch the rotational speed of the high-speed mixer to 900 r / min. After the material temperature drops to 90°C, discharge the pretreated material after the material temperature drops to 90°C;

[0075] The pretreated material is dispersed, plasticized and extruded through a parallel three-screw extruder. The heating temperatures of the extruder are set as follows: zone 1 at 210°C, zone 2 at 210°C, zone 3 at 210°C, zone 4 at 210°C, zone 5 at 195°C, zone 6 at 195°C, zone 7 at 190°C, zone 8 at 190°C, zone 9 at 185°C, zone 10 at 185°C, zone 11 at 185°C, zone 12 at 185°C, screen changer at 195°C, and die head at 195°C. The rotational speed of the extruder is 1100 r / min, the feeding rotational speed is 1100 r / min, and the main motor current is 320 A. The material extruded from the extruder is pelletized, water-cooled, dehydrated, and screened, and then enters the storage bin. After passing the inspection, the masterbatch is packaged to obtain the polypropylene drawing masterbatch.

[0076] Comparative Example 1

[0077] Based on Example 1, the difference from Example 1 is that the calcium carbonate powder used is produced by a conventional mill from ordinary raw ore. The particle size of this powder is: D50 is 2.87 μm, D97 is 7.81 μm, D100 is 12.20 μm, the content of ≤2 μm is 29.63 wt%, the whiteness is 96%, and the oil absorption value of the powder is 30 mL / 100 g.

[0078] Comparative Example 2

[0079] Mix 300 parts of the calcium carbonate powder described in Example 1 with 4 parts of aluminate coupling agent in a high-speed mixer. The set rotation speed of the high-speed mixer is 1500 r / min, the temperature of the mineral type heat transfer oil L-QB300 is 120 °C, and mix for 5 min. Keep the rotation speed of the high-speed mixer at 1500 r / min unchanged, then add 6 parts of polyethylene wax, 3 parts of stearic acid, 4 parts of POE toughening agent, and mix at 120 °C for 4 min. Subsequently, add 37.5 parts of polypropylene resin 085 and 0.1 part of antioxidant B215, and mix for 5 min until the material temperature reaches 170 °C. When the current of the high-speed mixer reaches 280 A, switch the rotation speed of the high-speed mixer to 900 r / min. After the material temperature drops to 90 °C, discharge the pretreated material.

[0080] The pretreated material is dispersed and plasticized and extruded through a parallel three-screw extruder. The set heating temperature of the extruder is 210 °C in zone 1, 210 °C in zone 2, 210 °C in zone 3, 210 °C in zone 4, 195 °C in zone 5, 195 °C in zone 6, 190 °C in zone 7, 190 °C in zone 8, 185 °C in zone 9, 185 °C in zone 10, 185 °C in zone 11, 185 °C in zone 12, 195 °C for the screen changer, and 195 °C for the die head. The rotation speed of the extruder is 1100 r / min, the feeding rotation speed is 900 r / min, and the main machine current is 350 A. The material extruded from the extruder is pelletized, water-cooled, dewatered, and screened and then enters the storage bin. After the masterbatch passes the inspection, it is packaged to obtain the polypropylene drawing masterbatch.

[0081] Application Example 1

[0082] Respectively, use the polypropylene drawing masterbatches prepared in Examples 1-2 and Comparative Examples 1-2 as modifiers and mix them with polypropylene and then draw (the addition amount of the polypropylene drawing masterbatch is 20 wt%);

[0083] Among them, 20 parts of polypropylene drawing masterbatch and 80 parts of T30S polypropylene are evenly mixed and put into a twin-screw extruder. The parameters of the drawing equipment are as follows: the heating temperature of the extruder is 230 °C, the temperature of the flat filament oven is 195 °C, the main machine speed is 70 r / min, the main machine current is 180 A, the linear speed of the film lifting roller is 50 m / min, and the linear speed of the traction roller is 50 m / min; the linear speeds of the drawing roller, the heat setting roller 1, the heat setting roller 2, and the cold setting roller are the corresponding maximum drawing speeds.

[0084] When using the polypropylene drawing masterbatch prepared in Example 1 or Example 2, the linear speed of the drawing roller is 460 m / min, the linear speed of the heat setting roller 1 is 460 m / min, the linear speed of the heat setting roller 2 is 460 m / min, and the linear speed of the cold setting roller is 460 m / min to obtain flat filaments.

[0085] When using the polypropylene drawing masterbatch prepared in Comparative Example 1, the linear speed of the drawing roller is 380 m / min, the linear speed of the heat setting roller 1 is 380 m / min, the linear speed of the heat setting roller 2 is 380 m / min, and the linear speed of the cold setting roller is 380 m / min.

[0086] When using the polypropylene drawing masterbatch prepared in Comparative Example 2, the linear speed of the drawing roller is 350 m / min, the linear speed of the heat setting roller 1 is 350 m / min, the linear speed of the heat setting roller 2 is 350 m / min, and the linear speed of the cold setting roller is 350 m / min.

[0087] The maximum drawing speed refers to the linear speed of the actual equipment drawing roller under the condition of ensuring normal flat filament drawing production. If the linear speed of the drawing roller is further increased, the flat filament will break during the stretching process and cannot be normally stretched into flat filaments.

[0088] The tensile strength and elongation rate of different flat filaments are tested according to GB / T1040-2008, and the results are shown in Table 1:

[0089] Table 1 Properties of flat filaments obtained by modifying polypropylene with the polypropylene drawing masterbatch prepared in Examples 1-2 and Comparative Examples 1-2

[0090]

[0091] As can be seen from Table 1, the thickness of the flat filaments obtained by Examples 1-2 and Comparative Examples 1-2 using a parallel triple-screw extruder is between 0.044 and 0.050 mm, and the width is 2.9 ± 0.1 mm. The flat filaments obtained by modifying polypropylene with the polypropylene drawing masterbatch prepared in Examples 1-2 as a modifier can be drawn at a maximum speed of 460 m / min, with a tensile force reaching 48.6 N and an elongation at break of up to 26.2%; all are higher than those of the flat filaments obtained when using the polypropylene drawing masterbatch prepared in Comparative Examples 1-2 as a modifier. It can be seen that when preparing plastic woven products, under the same addition amount of the drawing masterbatch, using the polypropylene drawing masterbatch of the present invention can obtain higher mechanical properties and the maximum drawing speed. The polypropylene drawing masterbatch provided by the present invention can improve the mechanical properties of polypropylene resin and improve the elongation at break of the flat filaments.

[0092] Application Example 2

[0093] According to the method described in Application Example 1, the polypropylene drawing masterbatch prepared in Example 1 was used as a modifier at addition amounts of 20 wt%, 25 wt%, 30 wt%, 35 wt%, and 40 wt% respectively, and mixed with polypropylene for drawing. The detection method was the same as that in Application Example 1, and the results are shown in Table 2.

[0094] Table 2 Properties of flat filaments obtained by modifying polypropylene with the polypropylene drawing masterbatch prepared in Example 1 with different contents

[0095]

[0096] As can be seen from Table 2, for the flat filaments obtained by modifying polypropylene with the polypropylene drawing masterbatch prepared in Example 1 as a modifier, their mechanical properties and the maximum drawing speed decrease with the increase of the polypropylene drawing masterbatch. When the addition amount of the polypropylene drawing masterbatch prepared in Example 1 is 35 wt%, the maximum drawing speed and mechanical property data of the obtained flat filaments are still slightly higher than the drawing speed and mechanical property data of the flat filaments obtained when the addition amount of the polypropylene drawing masterbatch prepared in Comparative Example 1 is 20 wt% in Table 1. Therefore, when preparing flat filaments with a normal drawing speed, compared with using Comparative Examples 1-2 or other existing drawing masterbatches, under the same drawing speed, the addition amount of the polypropylene drawing masterbatch of the present invention is large.

[0097] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A polypropylene drawing masterbatch, characterized in that, The preparation raw materials include the following parts by mass: The particle size distribution of the calcium carbonate powder: D50 is 2.3 - 3.3 μm, D97 is 6.9 - 7.9 μm, and D100 is 8.7 - 9.7 μm; In the calcium carbonate powder, the powder with a particle size ≤ 2 μm accounts for 32.2 - 33.2 wt%; the whiteness of the calcium carbonate powder is ≥ 98%, and the oil absorption value is 26 - 28 mL / 100 g; The surface modifier includes maleic anhydride grafted polyethylene wax.

2. The polypropylene drawing masterbatch according to claim 1, wherein The polypropylene includes at least one of the grades 045, 085, and T30S.

3. The polypropylene drawing masterbatch according to claim 1, characterized in that The lubricant includes at least one of stearic acid, polyethylene wax, Fischer - Tropsch wax, and paraffin wax.

4. The polypropylene drawing masterbatch according to claim 1, characterized in that, The dispersant includes at least one of metal stearates, ethylene bisstearamide, and monoglycerides.

5. The polypropylene drawing masterbatch according to claim 1, characterized in that, The antioxidant includes B215; the toughening agent includes at least one of POE, EVA, and maleic anhydride grafted polypropylene.

6. The preparation method of the polypropylene drawing masterbatch according to any one of claims 1 to 5, characterized in that, It includes the following steps: 1) Mix the calcium carbonate powder with the surface modifier and carry out co - blending modification to obtain modified calcium carbonate powder; 2) Mix the modified calcium carbonate powder with the lubricant, dispersant, toughening agent, polypropylene, and antioxidant and carry out pretreatment to obtain a pretreated material; 3) Extrude the pretreated material using a parallel twin - screw extruder to obtain a polypropylene drawing masterbatch.

7. The preparation method according to claim 6, characterized in that, In step 1), the rotation speed of the co - blending modification is 1500 - 1700 r / min, the temperature is 120 - 125 °C, and the time is 3 - 5 min; In step 2), the mixing includes: first mixing the modified calcium carbonate powder with the lubricant, dispersant, and toughening agent, and then second - mixing the obtained mixed material with polypropylene and antioxidant; The rotation speed of the first mixing is 1500 - 1700 r / min, the temperature is 105 - 120 °C, and the time is 2 - 4 min; The rotation speed of the second mixing is 1500 - 1700 r / min, the temperature is 150 - 170 °C, and the time is 4 - 6 min.

8. The preparation method according to claim 6, wherein In step 3), the feeding rotation speed of the extrusion is 1000 - 1200 r / min, the heating temperature is 180 - 230 °C, the extrusion rotation speed is 1100 - 1500 r / min, and the main machine current of the extruder is 320 - 350 A.

9. The application of the polypropylene drawing masterbatch according to any one of claims 1 - 5 or the polypropylene drawing masterbatch prepared by the preparation method according to any one of claims 6 - 8 in plastic woven products.

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