Highlight polypropylene material and preparation method thereof

Abstract

The invention discloses a highlight polypropylene material and a preparation method thereof. The highlight polypropylene material is prepared from the following components in parts by weight: 42.6-83.1 parts of polypropylene with a medium-low melt index, 15-30 parts of polypropylene with a high melt index, 0-20 parts of barium sulfate, 0.2-0.8 part of a dispersing agent, 0.2-0.6 part of an antioxidant, 1-3 parts of white carbon black and 0.5-3 parts of titanium dioxide. The highlight polypropylene material is few in surface pocking marks, high in flatness and glossiness and very suitable for preparing white products such as household appliance shells or bathroom products.

Description

Technical Field

[0001] This invention belongs to the field of polymer material modification technology, specifically relating to a high-gloss polypropylene material and its preparation method. Background Technology

[0002] Polypropylene is one of the most widely used general-purpose plastics, and it is widely used in automotive interior and exterior trim, electronic appliances, household appliance housings, and daily consumer goods.

[0003] When used in appliance casings or bathroom products, customers typically have high requirements for the surface gloss and appearance, especially for white products, which require high brightness and smoothness. However, ordinary modified polypropylene is difficult to use because the filler is difficult to disperse evenly and the material itself has significant post-shrinkage. Even with high-gloss injection molding, it is difficult to obtain products without pitting, with high smoothness and high gloss. Summary of the Invention

[0004] In view of this, the present invention needs to provide a high-gloss polypropylene material. By selecting the type and proportion of polypropylene used in the polypropylene system formulation and adding silica as a surface improving agent, a high-gloss polypropylene material with no pitting on the surface can be obtained, thereby expanding the application field of polypropylene.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The first aspect of this invention discloses a high-gloss polypropylene material, which is prepared by weight proportions of 42.6-83.1 parts of medium-low melt index polypropylene, 15-30 parts of high melt index polypropylene, 0-20 parts of barium sulfate, 0.2-0.8 parts of dispersant, 0.2-0.6 parts of antioxidant, 1-3 parts of silica and 0.5-3 parts of titanium dioxide.

[0007] In a further embodiment, the medium-low melt flow index polypropylene is at least one of copolymer polypropylene and homopolymer polypropylene with a melt flow index of 1-38 g / 10 min under the test conditions of 230℃ and 2.16Kg.

[0008] In a further embodiment, the high melt flow index polypropylene is at least one of copolymer polypropylene and homopolymer polypropylene with a melt flow index of 40-160 g / 10 min under test conditions of 230℃ and 2.16 kg.

[0009] In a further embodiment, the barium sulfate is barium sulfate ore powder with a particle size of 1000-5000 mesh.

[0010] In a further embodiment, the dispersant is a silicone-based dispersant.

[0011] In a further embodiment, the antioxidant is at least one or a mixture of two or more of hindered amine antioxidants, hindered phenolic antioxidants, and phosphite antioxidants in any mass ratio.

[0012] In a further embodiment, the particle size of the silica is 20-500 nm.

[0013] In a further embodiment, the titanium dioxide is in the rutile crystal form.

[0014] A second aspect of the present invention provides a method for preparing a high-gloss polypropylene material as described in the first aspect of the present invention, comprising the following steps:

[0015] After thoroughly mixing medium and low melt index polypropylene, high melt index polypropylene, barium sulfate, dispersant, antioxidant, silica and titanium dioxide according to the weight ratio, a homogeneous mixture is obtained.

[0016] The mixture is added to a twin-screw extruder for melt extrusion granulation to obtain a high-gloss polypropylene material.

[0017] In a further embodiment, the thorough mixing is achieved by dry mixing in a high-speed mixer for 10-20 minutes.

[0018] And / or, the processing temperatures of each zone of the twin-screw extruder are, in sequence, zone 1 temperature 170-190℃, zone 2 temperature 180-200℃, zone 3 temperature 180-210℃, zone 4 temperature 190-220℃, and zone 5 temperature 190-220℃.

[0019] The beneficial effects of this invention are:

[0020] This invention, based on existing modified plastics processes, adjusts the polypropylene system formulation to obtain a high-gloss polypropylene material with a smooth, pitted surface. Specifically:

[0021] (1) This invention obtains high-gloss polypropylene with good appearance by adding polypropylene with different melt indices to the formulation and adjusting their proportions. Among them, polypropylene with medium and low melt indices provides good rigidity-toughness balance and injection molding stability of the matrix. At the same time, the appropriate proportion of high melt index polypropylene makes the material flow more easily during injection molding. Moreover, since the molecular chains of high melt index polypropylene are shorter and flow more easily, high melt index polypropylene can easily cover the surface of the part. In addition, the short molecular chains are easy to arrange tightly during cooling, thereby obtaining a higher surface crystallinity and making the obtained polypropylene material have a higher surface smoothness.

[0022] (2) This invention helps to obtain better surface effects by adding a small amount of silica as an additive to the formulation. By selecting silica with nano-sized particles, due to its abundant hydroxyl groups and high specific surface area, when added in small amounts, silica can construct a three-dimensional network structure during the material melting injection molding process and the holding pressure process, due to its own van der Waals forces and mutual adsorption, which improves the melt strength and makes it easier to maintain surface smoothness during the crystallization process.

[0023] (3) The addition of a relatively large amount of titanium dioxide in this invention can improve the surface hardness of the material. On the one hand, it helps the silica to improve the melt strength of the material and the surface hardness of the parts. On the other hand, it has better light-shielding and light-reflecting properties, which helps to obtain parts with high gloss and good appearance.

[0024] (4) Use high-mesh barium sulfate material to avoid large-diameter particles accumulating on the surface and causing surface pitting. In addition, the selection of the formula ratio can help the barium sulfate powder to be evenly dispersed in the matrix. Detailed Implementation

[0025] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. Furthermore, unless otherwise specified, methods not specifically described in terms of conditions or steps are conventional methods, and the reagents and materials used are commercially available. In the following examples and comparative examples, "parts," "number of parts," etc., refer to parts by weight.

[0027] The specific raw material information in the examples and comparative examples is as follows:

[0028] Polypropylene PP Z30S, PP K7100, PPT30S, PP K7780, PP S2040, Sinopec;

[0029] Polypropylene PP BX3920, PP BX3800, PP BX3950, SK Chemicals, South Korea;

[0030] Polypropylene (PP) YPJ1215C, Yangzi Petrochemical;

[0031] Barium sulfate BSM-M, Guizhou Haoteng Mining Investment Co., Ltd.;

[0032] Barium sulfate 110, Simon Chemical;

[0033] Barium sulfate, Shanghai Weiyi;

[0034] Silicone masterbatch E525, Evonik Chemicals;

[0035] Silicone powder-500, Changzhou Rongdian Chemical Co., Ltd.

[0036] Antioxidant 1010, Antioxidant 168, BASF;

[0037] Silica TS-530, LM-150, SIL-M5, Cabot;

[0038] Titanium dioxide R218, rutile type, Shanghai Yuanjiang Chemical Co., Ltd.

[0039] Example 1

[0040] According to the weight ratio, 60 parts of medium-low melt index polypropylene PP Z30S, 20 parts of high melt index polypropylene PP BX3920, 15 parts of barium sulfate BSM-M, 0.6 parts of dispersant silicone masterbatch E525, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 2 parts of silica TS-530 and 2 parts of titanium dioxide were dry-mixed for 15 minutes to obtain a uniform mixture.

[0041] The above mixture is added to a twin-screw extruder for melt extrusion granulation. The operating temperatures of each zone of the twin-screw extruder are as follows: Zone 1: 175℃, Zone 2: 190℃, Zone 3: 195℃, Zone 4: 195℃, and Zone 5: 200℃, to obtain a high-gloss polypropylene material.

[0042] Example 2

[0043] According to the weight ratio, 59.4 parts of medium-low melt index polypropylene PP BX3800, 25 parts of high melt index polypropylene PPK7100, 10 parts of barium sulfate, 0.4 parts of dispersant silicone masterbatch E525, 0.3 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 2.5 parts of silica LM-150 and 2.2 parts of titanium dioxide were dry mixed for 18 minutes to obtain a uniform mixture.

[0044] The above mixture was added to a twin-screw extruder for melt extrusion granulation. The operating temperatures of each zone of the twin-screw extruder were as follows: Zone 1: 180°C, Zone 2: 180°C, Zone 3: 185°C, Zone 4: 190°C, and Zone 5: 200°C, to obtain high-gloss polypropylene material.

[0045] Example 3

[0046] According to the weight ratio, 73.4 parts of polypropylene PPT30S, 18 parts of high melt index polypropylene PP BX3950, 5 parts of barium sulfate, 0.5 parts of dispersant silicone powder-500, 0.1 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 1.5 parts of silica SIL-M5, and 1.3 parts of titanium dioxide were dry-mixed for 15 minutes to obtain a uniform mixture.

[0047] The above mixture was added to a twin-screw extruder for melt extrusion granulation. The operating temperatures of each zone of the twin-screw extruder were as follows: zone 1: 190°C, zone 2: 200°C, zone 3: 205°C, zone 4: 205°C, and zone 5: 200°C, to obtain high-gloss polypropylene material.

[0048] Example 4

[0049] According to the weight ratio, 83.1 parts of medium-low melt index polypropylene PP YPJ1215C, 15 parts of high melt index polypropylene PPK7780, 0.2 parts of dispersant silicone powder-500, 0.2 parts of antioxidant 1010, 1 part of silica TS-530 and 0.5 parts of titanium dioxide were dry mixed for 10 minutes to obtain a uniform mixture.

[0050] The above mixture was added to a twin-screw extruder for melt extrusion granulation. The operating temperatures of each zone of the twin-screw extruder were 170°C in zone 1, 180°C in zone 2, 180°C in zone 3, 190°C in zone 4, and 190°C in zone 5, to obtain high-gloss polypropylene material.

[0051] Example 5

[0052] According to the weight ratio, 42.6 parts of medium-low melt index polypropylene PP S2040, 30 parts of high melt index polypropylene PPBX3920, 20 parts of barium sulfate 110, 0.8 parts of dispersant silicone masterbatch E525, 0.3 parts of antioxidant 1010, 0.3 parts of antioxidant 168, 3 parts of silica TS-530 and 3 parts of titanium dioxide were dry mixed for 20 minutes to obtain a uniform mixture.

[0053] The above mixture was added to a twin-screw extruder for melt extrusion granulation. The operating temperatures of each zone of the twin-screw extruder were as follows: Zone 1: 190℃, Zone 2: 200℃, Zone 3: 210℃, Zone 4: 220℃, and Zone 5: 220℃, to obtain high-gloss polypropylene material.

[0054] Comparative Example 1

[0055] This comparative example uses the same implementation method as Example 1, except that "60 parts of polypropylene PP Z30S and 20 parts of high melt flow index polypropylene PP BX3920" are replaced with "80 parts of polypropylene PP Z30S". The specific steps are as follows:

[0056] According to the weight ratio, 80 parts of polypropylene PP Z30S, 15 parts of barium sulfate BSM-M, 0.6 parts of dispersant silicone masterbatch E525, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168, 2 parts of silica TS-530 and 2 parts of titanium dioxide were dry mixed for 15 minutes to obtain a uniform mixture.

[0057] The above mixture is added to a twin-screw extruder for melt extrusion granulation. The operating temperatures of each zone of the twin-screw extruder are as follows: Zone 1: 175°C, Zone 2: 190°C, Zone 3: 195°C, Zone 4: 195°C, and Zone 5: 200°C, to obtain polypropylene material.

[0058] Comparative Example 2

[0059] This comparative example uses the same implementation method as Example 1, except that "60 parts polypropylene PP Z30S and 2 parts silica TS-530" are replaced with "62 parts polypropylene PP Z30S". The specific steps are as follows:

[0060] According to the weight ratio, 62 parts of polypropylene (PP) Z30S, 20 parts of high melt index polypropylene (PP) BX3920, 15 parts of barium sulfate (BSM-M), 0.6 parts of dispersant silicone masterbatch (E525), 0.2 parts of antioxidant (1010), 0.2 parts of antioxidant (168) and 2 parts of titanium dioxide were dry-mixed for 15 minutes to obtain a uniform mixture.

[0061] The above mixture is added to a twin-screw extruder for melt extrusion granulation. The operating temperatures of each zone of the twin-screw extruder are as follows: Zone 1: 175℃, Zone 2: 190℃, Zone 3: 195℃, Zone 4: 195℃, and Zone 5: 200℃, to obtain a high-gloss polypropylene material.

[0062] Comparative Example 3

[0063] This comparative example uses the same implementation method as Example 1, except that "60 parts of polypropylene PP Z30S, 20 parts of high melt flow index polypropylene PP BX3920, and 2 parts of silica TS-530" are replaced with "82 parts of polypropylene PP Z30S". The specific steps are as follows:

[0064] According to the weight ratio, 82 parts of polypropylene PP Z30S, 15 parts of barium sulfate BSM-M, 0.6 parts of dispersant silicone masterbatch E525, 0.2 parts of antioxidant 1010, 0.2 parts of antioxidant 168 and 2 parts of titanium dioxide were dry-mixed for 15 minutes to obtain a uniform mixture.

[0065] The above mixture is added to a twin-screw extruder for melt extrusion granulation. The operating temperatures of each zone of the twin-screw extruder are as follows: Zone 1: 175°C, Zone 2: 190°C, Zone 3: 195°C, Zone 4: 195°C, and Zone 5: 200°C, to obtain polypropylene material.

[0066] Performance testing

[0067] The high-gloss polypropylene materials prepared in the examples and comparative examples were used to prepare samples on a 5cm × 5cm high-gloss mold. The gloss of the glossy samples was tested at 60° using a BYK 1147104 gloss meter. In addition, surface pitting was visually observed. Pitting with a diameter of 0.05mm-0.25mm was counted as one pitting. Five samples of each type were grouped together, and the total number of pitting in each group was calculated (if any of the five samples had a pitting with a diameter greater than 0.25mm, the pitting effect of that group was directly judged as NG). The results are shown in Table 1.

[0068] Table 1

[0069] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Glossiness / ° 90.7 91.0 90.3 88.7 93.1 62.4 64.1 58.2 Pockmark level 1 2 3 3 1 NG NG NG

[0070] As can be seen from the test results in Table 1, the high-gloss polypropylene of this invention has high gloss, high smoothness, and few pits. It is very suitable for manufacturing appliance casings or bathroom products.

[0071] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0072] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A high-gloss polypropylene material, characterized in that, It is prepared by weight proportions of 42.6-83.1 parts of medium-low melt index polypropylene, 15-30 parts of high melt index polypropylene, 0-20 parts of barium sulfate, 0.2-0.8 parts of dispersant, 0.2-0.6 parts of antioxidant, 1-3 parts of silica and 0.5-3 parts of titanium dioxide.

2. The high-gloss polypropylene material as described in claim 1, characterized in that, The medium-low melt flow index polypropylene is at least one of copolymer polypropylene and homopolymer polypropylene with a melt flow index of 1-38 g / 10 min under the test conditions of 230℃ and 2.16Kg.

3. The high-gloss polypropylene material as described in claim 1, characterized in that, The high melt flow index polypropylene is at least one of copolymer polypropylene and homopolymer polypropylene with a melt flow index of 40-160 g / 10 min under the test conditions of 230℃ and 2.16Kg.

4. The high-gloss polypropylene material as described in claim 1, characterized in that, The barium sulfate is barium sulfate ore powder with a particle size of 1000-5000 mesh.

5. The high-gloss polypropylene material as described in claim 1, characterized in that, The dispersant is a silicone-based dispersant.

6. The high-gloss polypropylene material as described in claim 1, characterized in that, The antioxidant is at least one or a mixture of two or more of hindered amine antioxidants, hindered phenolic antioxidants, and phosphite antioxidants in any mass ratio.

7. The high-gloss polypropylene material as described in claim 1, characterized in that, The particle size of the silica is 20-500 nm.

8. The high-gloss polypropylene material as described in claim 1, characterized in that, The titanium dioxide is in the rutile crystal form.

9. A method for preparing a high-gloss polypropylene material as described in any one of claims 1-8, characterized in that, Includes the following steps: After thoroughly mixing medium and low melt index polypropylene, high melt index polypropylene, barium sulfate, dispersant, antioxidant, silica and titanium dioxide according to the weight ratio, a homogeneous mixture is obtained. The mixture is added to a twin-screw extruder for melt extrusion granulation to obtain a high-gloss polypropylene material.

10. The preparation method according to claim 9, characterized in that, The thorough mixing is achieved by dry mixing in a high-speed mixer for 10-20 minutes. And / or, the processing temperatures of each zone of the twin-screw extruder are, in sequence, zone 1 temperature 170-190℃, zone 2 temperature 180-200℃, zone 3 temperature 180-210℃, zone 4 temperature 190-220℃, and zone 5 temperature 190-220℃.