Polypropylene composite material, and preparation method and application thereof

Abstract

The application belongs to the field of high polymer materials and technology, and particularly relates to a polypropylene composition and a preparation method thereof. Specifically, the polypropylene composite material comprises the following components in parts by weight: polypropylene 59-81 parts, glass fiber 10-30 parts, polyacrylamide 3-10 parts, maleic anhydride grafted polypropylene 1-10 parts, and antioxidant 0.1-2 parts. The polypropylene composite material of the application is applied to the field of automobile functional parts, solves the problem of easy rupture of the melt in the blow molding process, and ensures a good product appearance, so that the related products made by the application have good appearance and performance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials and technology, and particularly relates to a polypropylene composition and its preparation method. Background Technology

[0002] Polypropylene is a thermoplastic material with characteristics such as low density, non-toxicity, environmental friendliness, and recyclability, making it widely used in many fields such as automobiles, home appliances, and chemicals. In the automotive industry, polypropylene resin is frequently used to replace metal materials in car pedals to speed up the pedal molding cycle, reduce production costs, and achieve lightweighting, which meets the development requirements of the automotive industry.

[0003] Car pedals must be strong enough to withstand repeated foot traffic. Ordinary polypropylene resin lacks sufficient mechanical strength; glass fiber must be added to achieve the required strength. To further reduce the weight of car pedals and achieve weight reduction, automakers are gradually adopting blow molding processes to manufacture them.

[0004] However, the melt strength of the glass fiber reinforced polypropylene composite is insufficient, making it prone to cracking during blow molding and unsuitable for 3D blow molding, thus failing to meet the requirements of 3D blow molding processes for automotive pedal materials. Secondly, the rapid crystallization rate of the polypropylene composite prevents it from fully encapsulating the glass fibers within the system, resulting in severe fiber shedding on the final product, reducing its aesthetic appeal and commercial value.

[0005] Chinese invention patent application CN115010920B discloses a high melt strength polypropylene and its preparation method. High melt strength is a key factor in blow-molded foot pedals. However, the application does not mention the appearance issue. If glass fiber is added to this type of polypropylene material, the resulting foot pedal will have a serious risk of fiber floating on the surface.

[0006] Chinese invention patent application CN109679028B discloses a high melt strength polypropylene and its preparation method, as well as polypropylene foam beads and their preparation method. This application mainly relates to the field of foam materials, but the strength cannot meet the requirements of blow-molded pedals and cannot be used in the production of automobile pedals. Summary of the Invention

[0007] The purpose of this invention is to solve the above-mentioned technical problems and provide a polypropylene composite material with high melt strength so as to prevent cracking during blow molding, and at the same time, it can fully wrap glass fibers during blow molding to ensure that the manufactured product has a good appearance.

[0008] Another object of the present invention is to provide a method for preparing the above-mentioned polypropylene composite material.

[0009] Another object of the present invention is to provide an application of the above-mentioned polypropylene composite material.

[0010] This invention is achieved through the following technical solution:

[0011] A polypropylene composite material, by weight, comprises the following components:

[0012] 59-81 parts of polypropylene;

[0013] 10-30 parts glass fiber;

[0014] 3-10 parts of polyacrylamide;

[0015] 1-10 parts of maleic anhydride-grafted polypropylene;

[0016] Antioxidant 0.1-2 parts;

[0017] The polypropylene is selected from copolymer polypropylene.

[0018] Preferably, the polypropylene melt flow rate is 0.1-10 g / 10 min, the test standard is in accordance with ISO 1133-2011, and the test conditions are a temperature of 230℃ and a load of 2.16 kg.

[0019] Preferably, the polypropylene accounts for no less than 59% of the mass percentage of the polypropylene composite material.

[0020] Preferably, the glass fiber has an average diameter of 10-15 μm and an average length of 3-5 mm.

[0021] Preferably, the weight ratio of polyacrylamide to maleic anhydride-grafted polyacrylamide is in the range of (1-4):1.

[0022] Preferably, the polyacrylamide is selected from cationic polyacrylamide, anionic polyacrylamide, or a mixture of cationic polyacrylamide and anionic polyacrylamide.

[0023] Preferred formulations include cationic polyacrylamide and a combination of cationic polyacrylamide and anionic polyacrylamide.

[0024] More preferably, a compound of cationic polyacrylamide / anionic polyacrylamide.

[0025] Preferably, the cationic polyacrylamide has a weight-average molecular weight of 4 million to 12 million, more preferably 9 million to 11 million; the anionic polyacrylamide has a weight-average molecular weight of 12 million to 20 million, and the detection method is: high-temperature GPC testing, the specific steps of which include:

[0026] Preparation of calibration standard substances: Select polymers with known molecular weights as calibration standard substances and prepare a set of standard substance solutions with different molecular weights.

[0027] Sample pretreatment: Dissolve the sample to be tested in a suitable solvent and perform necessary pretreatment steps, such as filtration to remove impurities.

[0028] Instrument calibration: calibrate various parameters of the GPC instrument, such as flow rate and temperature, to ensure that the instrument operates in optimal condition.

[0029] Sample injection: The calibration standard and the sample to be tested are injected sequentially into the column of the GPC instrument.

[0030] Column separation: In a GPC column, polymers in a solution are separated within the column due to their different molecular weights.

[0031] Detection: At the column outlet, use an appropriate detector to measure the solution's response signal, such as refractive index, light scattering, or viscosity.

[0032] Data processing: Based on the measurement results and response signals of the calibration standard material, data processing is performed using calculation and analysis software to plot molecular weight distribution curves or calculate average molecular weight, etc.

[0033] Preferably, the cationic polyacrylamide / anionic polyacrylamide compound has a weight ratio of cationic polyacrylamide to anionic polyacrylamide of 1:(0.01-5); more preferably, the weight ratio is 1:(0.5-1.5).

[0034] The inventors hypothesize that polyacrylamide can provide crosslinking points during blow molding, thereby increasing the overall melt strength, with the increase being more pronounced as the molecular weight increases. Anionic polyacrylamide also has a crosslinking effect, but the improvement is not as significant as that of cationic polyacrylamide. The inventors discovered that when anionic and cationic polyacrylamide are mixed in a certain proportion, the melt strength is further improved, and the appearance grade is also enhanced.

[0035] Preferably, the grafting rate of maleic anhydride-grafted polypropylene is 0.6-1.1%, and the detection method is acid-base titration.

[0036] Preferably, the antioxidant includes a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is selected from hindered phenolic antioxidants; and the secondary antioxidant is selected from phosphite antioxidants.

[0037] The primary antioxidant is selected from any one or more of 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene; the secondary antioxidant is selected from tris(2,4-di-tert-butylphenyl) phosphite.

[0038] Preferably, the primary antioxidant is selected from hindered phenolic antioxidants containing isocyanuric acid groups.

[0039] More specifically, the primary antioxidant is selected from 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid.

[0040] The isocyanuric acid group helps to improve the overall cross-linking degree, thereby further improving and resolving the melt strength and fiber floating problem of polypropylene composites.

[0041] Those skilled in the art can choose to add 0.1-2 parts of color masterbatch by weight according to actual needs.

[0042] This invention provides a method for preparing the above-mentioned polypropylene composite material, comprising the following steps: mixing the components evenly according to the formula, and granulating by extrusion through a screw extruder, wherein the screw temperature range is 180-210℃ and the screw speed is 450-500 rpm.

[0043] The present invention also provides an application of the above-mentioned polypropylene composite material for the manufacture of automotive functional parts.

[0044] In addition, the present invention provides a blow-molded article comprising the above-mentioned polypropylene composite material.

[0045] The present invention has the following beneficial effects:

[0046] This invention, by combining copolymerized polypropylene with polyacrylamide, provides crosslinking points for the composite system, significantly improving the melt strength of fiber-reinforced polypropylene composites. It also achieves a more thorough fiber encapsulation effect during blow molding, preventing fiber detachment from the surface. The polypropylene composite material provided by this invention solves the problem of melt fracture during blow molding while ensuring excellent product appearance. Detailed Implementation

[0047] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. 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. These all fall within the scope of protection of the present invention.

[0048] The raw materials used in this invention are sourced from the following sources:

[0049] Polypropylene 1: PP T30S, homopolymer polypropylene, with a melt flow rate of 3.0 g / 10min at 230℃ and 2.16 Kg load, purchased from Sinopec.

[0050] Polypropylene 2: PP B8101, a copolymer polypropylene, with a melt flow rate of 0.5 g / 10 min at 230℃ and 2.16 kg load, purchased from Sinopec.

[0051] Polypropylene 3: PP 3010, a copolymer polypropylene, with a melt flow rate of 1.1 g / 10 min at 230℃ and 2.16 Kg load, purchased from Plastics Industry Co., Ltd.

[0052] Maleic anhydride-grafted polypropylene 1: BONDYRAM 1001CN, grafting rate 0.8%, purchased from Polyram.

[0053] Maleic anhydride-grafted polypropylene 2: PA-BOND 363C, grafting rate 0.7%, purchased from Ploymer Asia.

[0054] Glass fiber: ECS13-4.5-T538D, monofilament diameter 13μm, chopped length 4.5mm, purchased from Taishan Glass Fiber Co., Ltd.

[0055] Polyacrylamide 1: C508, cationic, molecular weight 5 million, purchased from Mitsui Chemicals.

[0056] Polyacrylamide 2: C507, cationic, molecular weight 7 million, purchased from Mitsui Chemicals.

[0057] Polyacrylamide 3: C535, cationic, molecular weight 10 million, purchased from Mitsui Chemicals.

[0058] Polyacrylamide 4: A130, anionic, molecular weight 13 million, purchased from Mitsui Chemicals.

[0059] Polyacrylamide 5: A95, anionic, molecular weight 15 million, purchased from Mitsui Chemicals.

[0060] Polyacrylamide 6: A110, anionic, molecular weight 19 million, purchased from Mitsui Chemicals.

[0061] Color masterbatch: PLASBLAK® PE2772KF, purchased from CABOT.

[0062] Main antioxidant 1: SONOX 1010, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], hindered phenol, purchased from Shandong Linyi Sanfeng Chemical Co., Ltd.

[0063] Main antioxidant 2: AO-330, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, hindered phenol, purchased from Adico.

[0064] Main antioxidant 3: SONOX 3114, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid, hindered phenol, purchased from Shandong Linyi Sanfeng Chemical Co., Ltd.

[0065] Co-antioxidant: SONOX 168, tris(2,4-di-tert-butylphenyl) phosphite, a phosphite ester, purchased from Shandong Linyi Sanfeng Chemical Co., Ltd.

[0066] The test methods of this invention are as follows:

[0067] (1) Appearance test: Injection molded 100*100*3mm square plate, visually evaluate the appearance of fiber floating. Set the level: Level 0: No fiber floating; Level 1: Very slight; Level 2: Slightly visible; Level 3: Clearly visible; Level 4: Relatively serious; Level 5: Very serious.

[0068] (2) Melt strength test: The melt strength was measured by a Hacker rheometer at a temperature of 190℃, and the unit is N.

[0069] Table 1. Weight parts and test results of each component of the propylene composite materials in Examples 1-9

[0070] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9 Polypropylene 2 70 Polypropylene 3 60 80 75.6 75.6 75.6 75.6 75.6 75.6 Maleic anhydride-grafted polypropylene 1 1 5 3 3 3 3 3 3 Maleic anhydride-grafted polypropylene 2 10 Fiberglass 10 20 30 20 20 20 20 20 20 Polyacrylamide 1 3 6 Polyacrylamide 2 6 Polyacrylamide 3 7 6 Polyacrylamide 4 6 Polyacrylamide 5 6 Polyacrylamide 6 10 6 Masterbatch 1 1 1 1 1 1 1 1 1 Main antioxidant 1 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Main antioxidant 2 0.2 Main antioxidant 3 0.2 Co-antioxidants 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Melt strength test / N 0.21 0.33 0.33 0.29 0.31 0.32 0.27 0.29 0.3 Appearance test 2 2 3 2 2 2 2 2 2

[0071] As can be seen from Examples 4-9, the polypropylene composition with added cationic polyacrylamide has higher melt strength than the polypropylene composition with added anionic polyacrylamide, and the higher the molecular weight of the polyacrylamide, the higher the melt strength.

[0072] Table 2. Weight parts and test results of each component of the propylene composite material in Examples 10-14

[0073] Example 10 Example 11 Example 12 Example 13 Example 14 Polypropylene 3 75.6 75.6 75.6 75.6 75.6 Maleic anhydride-grafted polypropylene 1 3 3 3 3 3 Fiberglass 20 20 20 20 20 Polyacrylamide 3 0.5 2 3 3 3 Polyacrylamide 6 5.5 4 3 3 3 Masterbatch 1 1 1 1 1 Main antioxidant 1 0.2 0.2 0.2 Main antioxidant 2 0.2 Main antioxidant 3 0.2 Co-antioxidants 0.2 0.2 0.2 0.2 0.2 Melt strength test / N 0.32 0.34 0.36 0.36 0.45 Appearance test 1 1 1 1 0

[0074] As can be seen from Examples 10-12, when the weight ratio of cationic polyacrylamide to anionic polyacrylamide is in the range of 1:(0.01-5), the performance is better, and when the weight ratio is 1:(0.5-1.5), the performance is even better.

[0075] Table 3. Weight parts of each component and test results of propylene composites in Comparative Examples 1-3

[0076] Comparative Example 1 Comparative Example 2 Comparative Example 3 Polypropylene 1 75.6 Polypropylene 3 75.6 75.6 Maleic anhydride-grafted polypropylene 1 3 3 Fiberglass 20 20 20 Polyacrylamide 3 3 3 Polyacrylamide 6 3 3 Masterbatch 1 1 1 Main antioxidant 1 0.2 Main antioxidant 3 0.2 0.2 Co-antioxidants 0.2 0.2 0.2 Melt strength test / N 0.15 0.13 0.02 Appearance test 5 4 2

[0077] Comparative Example 1 is a conventional glass fiber reinforced polypropylene system. The resin matrix is ​​selected from homopolymer polypropylene. During the blow molding process, due to the excessively fast crystallization rate, the glass fibers cannot be fully wrapped, resulting in severe fiber floating in the product. In addition, the melt strength of this polypropylene composite material is also low.

[0078] Comparative Example 2, without the addition of maleic anhydride-grafted polypropylene, showed inferior melt strength and appearance compared to the Example.

[0079] Comparative Example 3, without the addition of polyacrylamide, showed a significant decrease in melt strength compared to the examples.

Claims

1. A polypropylene composite, characterized in that, By weight parts, comprising the following components: Polypropylene 59-81 parts; Glass fiber 10-30 parts; Polyacrylamide 3-10 parts; Maleic anhydride grafted polypropylene 1-10 parts; Antioxidant 0.1-2 parts; The polypropylene is selected from copolymerized polypropylene.

2. The polypropylene composite material according to claim 1, the weight ratio of the polyacrylamide to the maleic anhydride grafted polypropylene ranges from (1-4):

1.

3. The polypropylene composite of claim 1, wherein, The polyacrylamide is selected from cationic polyacrylamide, anionic polyacrylamide, or a complex of cationic polyacrylamide / anionic polyacrylamide.

4. The polypropylene composite of claim 3, wherein, The polyacrylamide is selected from cationic polyacrylamide, a complex of cationic polyacrylamide / anionic polyacrylamide.

5. The polypropylene composite of claim 4, wherein, The polyacrylamide is selected from a complex of cationic polyacrylamide / anionic polyacrylamide.

6. The polypropylene composite material according to claim 3, the weight average molecular weight of the cationic polyacrylamide is 4 million-12 million.

7. The polypropylene composite material according to claim 6, the weight average molecular weight of the cationic polyacrylamide is 9 million-11 million.

8. The polypropylene composite of claim 3, wherein, The weight ratio of cationic polyacrylamide to anionic polyacrylamide in the complex of cationic polyacrylamide / anionic polyacrylamide is 1:(0.01-5).

9. The polypropylene composite of claim 8, wherein, The weight ratio of cationic polyacrylamide to anionic polyacrylamide in the complex of cationic polyacrylamide / anionic polyacrylamide is 1:(0.5-1.5).

10. The polypropylene composite of claim 1, wherein, The antioxidant comprises a primary antioxidant and a secondary antioxidant, the primary antioxidant is selected from hindered phenolic antioxidants; the secondary antioxidant is selected from phosphite antioxidants.

11. The polypropylene composite of claim 10, wherein, The primary antioxidant is selected from hindered phenolic antioxidants containing isocyanuric acid groups.

12. The polypropylene composite of claim 1, wherein, Further comprising 0.1-2 parts of color master by weight fraction.

13. Process for the production of a polypropylene composite material according to any one of claims 1 to 12, characterized in that, Comprising the following steps, according to the ratio, mix each component uniformly, and extrude and granulate through a screw extruder.

14. Use of the polypropylene composite according to any one of claims 1 to 12, characterized in that For preparing automobile functional parts.

15. A blow molded article characterized by, Comprising the polypropylene composite material according to any one of claims 1-12.