Polypropylene composition, process for its preparation and use thereof

Abstract

The application discloses a polypropylene composition and belongs to the field of high polymer materials and technologies. Specifically, the polypropylene composition comprises the following components: 29-61 parts of polypropylene, 1-8 parts of maleic anhydride grafted polypropylene, 5-25 parts of acrylate elastomer, 1-6 parts of azo initiator and 35-45 parts of glass fiber. The polypropylene composition has the advantages of high strength, high weather resistance and color change resistance, and can be applied to the preparation of water purification processor components.

Description

Technical Field

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

[0002] Polypropylene (PP) is a polymer compound formed by the polymerization of propylene. The main characteristics of PP materials are low density and light weight, as well as good insulation, corrosion resistance, abrasion resistance, and impact resistance. Furthermore, PP has a high melting temperature, allowing it to withstand high operating temperatures. These properties make PP materials perform exceptionally well in various fields such as packaging, medical, construction, home appliances, and automobiles.

[0003] However, PP materials also face some challenges in application, such as ultraviolet radiation, high temperature environment and chemical corrosion, which may cause problems such as material discoloration and performance degradation.

[0004] Chinese invention patent CN115010920A discloses a high melt strength polypropylene and its preparation method. The high melt strength polypropylene is obtained through a synthetic reaction of polypropylene and a hyperbranched crosslinking agent. This method allows control over the degree of crosslinking in the high melt strength polypropylene, controlling gel formation and avoiding the reduction in material processing performance caused by gel formation. While improving melt strength, it also enhances the overall structural strength, but it does not address the issue of color change.

[0005] Chinese invention patent CN102532701A discloses a low-warpage, creep-resistant polypropylene composition and its preparation method. It uses a compatibilizer and a nucleating agent to improve the creep resistance and warpage properties of polypropylene. This invention can improve the overall creep performance of the material, thereby enhancing its structural strength; however, the improvement is insufficient, and cracking still occurs at 23°C and 6 bar pressure.

[0006] Therefore, the existing technology lacks a polypropylene composition that has high compressive strength and is not easily discolored. Summary of the Invention

[0007] The purpose of this invention is to overcome the above-mentioned technical problems and provide a polypropylene composition with high strength, high weather resistance, and color change resistance.

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

[0009] Another object of the present invention is to provide the application of the above-described polypropylene composition.

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

[0011] A polypropylene composition, comprising, by weight, the following components

[0012] Polypropylene 29-61 parts;

[0013] 1-8 parts of maleic anhydride-grafted polypropylene;

[0014] 5-25 parts of acrylate elastomer;

[0015] 1-6 parts of azo initiator;

[0016] 35-45 parts glass fiber;

[0017] The polypropylene is selected from homopolymer polypropylene.

[0018] Preferably, the melt flow rate of the polypropylene is 5-30 g / 10 min, and the testing conditions are: 230℃, 2.16 kg.

[0019] In this invention, the polypropylene accounts for no less than 29% of the mass percentage of the polypropylene composition.

[0020] Preferably, the melt flow rate of the maleic anhydride-grafted polypropylene is 80-140 g / 10 min, the testing conditions are 190℃, 2.16 kg, and the testing standard is ISO 1133-1:2022.

[0021] Preferably, the density of the maleic anhydride-grafted polypropylene is 0.900-0.915 g / cm³. 3 The grafting rate is 0.8-1.2%.

[0022] Maleic anhydride-grafted polypropylene can be used as a compatibilizer to improve the compatibility between polypropylene and glass fiber.

[0023] Preferably, the butyl acrylate content in the acrylate elastomer is 17-30 wt%.

[0024] More preferably, the butyl acrylate content in the acrylate elastomer is 20-30 wt%.

[0025] Specifically, acrylate elastomers can be selected from: ethylene-methacrylate-butyl acrylate terpolymers and zinc ionomers, ethylene-methacrylate-butyl acrylate terpolymers, ethylene-butyl acrylate-glycidyl methacrylate terpolymers, or ethylene-butyl acrylate copolymers.

[0026] Acrylic elastomers can improve the weather resistance of polypropylene compositions to some extent, and the improvement in burst pressure performance is even more significant. Butyl acrylate, a type of acrylic elastomer, can increase the degree of cross-linking of polypropylene molecular chains during processing, leading to a more complex network structure and thus enhancing the structural strength of the polypropylene composition.

[0027] Test results show that increasing the amount of acrylate elastomer can improve the burst pressure of polypropylene compositions. However, the amount of acrylate elastomer added is not always better. After reaching a certain upper limit, the effect of adding more acrylate elastomer on improving the burst pressure of polypropylene compositions gradually weakens, and further increasing the amount of acrylate elastomer added has no effect on the burst pressure.

[0028] The test results further indicate that as the butyl acrylate content in the acrylate elastomer increases, the burst pressure of the polypropylene composition increases.

[0029] Preferably, the molecular weight of the azo initiator is 150-300;

[0030] More preferably, the molecular weight of the preferred azo initiator is 200-300.

[0031] The molecular weight of azo initiators has a significant impact on molecular chain entanglement, thus affecting the burst pressure.

[0032] The discoloration of composite materials is caused by the generation of anthraquinones as a byproduct during the action of antioxidants. These substances are yellow in nature. This invention can neutralize the anthraquinones generated during the antioxidant processing by adding an azo initiator, thereby reducing the yellow substances and improving the discoloration problem.

[0033] Test results show that increasing the content of azo initiators results in less color change in the polypropylene composition. However, further increasing the content of azo initiators beyond the upper limit can easily lead to material degradation. After degradation, the molecular chains break, the performance drops sharply, and the material pulverizes.

[0034] Preferably, the processing aids include a primary antioxidant and a secondary antioxidant.

[0035] Preferably, the primary antioxidant is selected from hindered phenols, and the secondary antioxidant is selected from phosphites.

[0036] Those skilled in the art may add 0-5 parts by weight of the adjuvant as needed.

[0037] Preferably, the additives are selected from: 0-2 parts of colorant; 0-1 parts of antioxidant; and 0-1 parts of light stabilizer.

[0038] Preferably, the colorant can be added in the form of masterbatch.

[0039] The present invention also provides a method for preparing the above-mentioned polypropylene composition, comprising the following steps: weighing each component except the azo initiator according to the weight parts and mixing them evenly in a high-speed mixer to obtain a mixture; adding the mixture to a twin-screw extruder, adding the azo initiator through side feeding, melt mixing, extruding and granulating to obtain the polypropylene composition.

[0040] Preferably, the melt mixing temperature is 180~210℃ and the screw speed is 450~500 rpm.

[0041] The present invention also provides the application of the above-described polypropylene composition in the preparation of water purification processor components.

[0042] The present invention has the following beneficial effects:

[0043] Compared with existing technologies, this invention improves the burst pressure performance of the polypropylene composition by adding acrylate elastomers; simultaneously, by adding azo initiators, it neutralizes anthraquinone substances that appear during antioxidant processing and use, thereby improving discoloration. The polypropylene composition provided by this invention has good pressure resistance, weather resistance, and discoloration resistance. Detailed Implementation

[0044] 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.

[0045] Sources of raw materials used in this invention:

[0046] Polypropylene 1: M1200HS, homopolymer polypropylene, with a melt mass flow rate of 5-15 g / 10min at 230℃ and 2.16 Kg load, purchased from Sinopec.

[0047] Polypropylene 2: Z30S, homopolymer polypropylene, with a melt mass flow rate of 10-30 g / 10min at 230℃ and 2.16 Kg load, purchased from Sinopec.

[0048] Polypropylene 3: SP179 (Lanzhou Chemical), a copolymer polypropylene, has a melt flow rate of 5-15 g / 10min at 230℃ and 2.16 Kg load, purchased from Sinopec.

[0049] Maleic anhydride-grafted polypropylene: BONDYRAM 1001CN, with a melt volumetric flow rate of 80-140 g / 10min at 190℃ and 2.16 Kg load, purchased from Polyram.

[0050] Glass fiber: ECS13-4.5-T538D, monofilament diameter 13μm, chopped length 4.0-5.5mm, purchased from Taishan Glass Fiber Co., Ltd.

[0051] Acrylic elastomer 1: Surlyn® 9320, an ionomer of ethylene-methacrylate-butyl acrylate terpolymer and zinc ions, with 23% butyl acrylate content, purchased from DuPont.

[0052] Acrylic elastomer 2: Elvaloy AC3117, ethylene-methacrylic acid-butyl acrylate terpolymer, butyl acrylate content 17%, purchased from Dow.

[0053] Acrylic elastomer 3: LOTADER® AX8750, ethylene-butyl acrylate-glycidyl methacrylate terpolymer, butyl acrylate content 25%, purchased from Arkema.

[0054] Acrylic elastomer 4: Elvaloy@AC 3427, ethylene-butyl acrylate copolymer, butyl acrylate content 27%, purchased from DuPont.

[0055] Azo initiator 1: PERKADOX AIBN, molecular weight approximately 164.2, purchased from Nouryon.

[0056] Azo initiator 2: PERKADOX AMBN (azobisisoheptanenitrile), molecular weight approximately 192.3, purchased from Nouryon.

[0057] Azo initiator 3: 1,1'-azo (cyanocyclohexane) PERKADOX ACCN, molecular weight approximately 244.3, purchased from Nouryon.

[0058] Colorant: PLASBLAK® PE2772KF, purchased from CABOT.

[0059] Antioxidant 1: SONOX 1010, a hindered phenol, purchased from Shandong Linyi Sanfeng Chemical Co., Ltd.

[0060] Antioxidant 2: SONOX 168, a phosphite, purchased from Shandong Linyi Sanfeng Chemical Co., Ltd.

[0061] Test methods:

[0062] (1) Color Change Test: The comparative example and the embodiment were directly injection molded into 100*100*3mm square plates. According to the PV3930 standard, the gray scale grade and ΔE data were evaluated after two cycles of 3200h. The gray scale grade is used to reflect the degree of color change of the material, and ΔE reflects the color difference. In this invention, the gray scale grade is required to be ≥4 and ΔE ≤3.2.

[0063] (2) Pressure resistance test: The examples and comparative examples were injection molded into finished products, and then static pressure test was carried out at room temperature of 23°C. The pressure when the parts burst was recorded.

[0064] Table 1. Weight parts of each component and test results of polypropylene compositions in Examples 1-12

[0065]

[0066] As can be seen from Examples 1-12, the polypropylene compositions provided by the present invention have a gray calorie grade of ≥4, a burst pressure of ≥6 Bar, and ΔE ≤3.2.

[0067] Table 2. Weight parts of each component and test results of the polypropylene compositions in Comparative Examples 1-4

[0068]

[0069] As shown in Comparative Example 1, without the addition of acrylate elastomers and azo initiators, the gray calorie grade drops to 3, ΔE > 3.2, and the burst pressure < 6. This polypropylene composition does not achieve both high compressive strength and resistance to discoloration.

[0070] As shown in Comparative Example 2, the polypropylene composition without the addition of an azo initiator exhibits significant color difference.

[0071] As shown in Comparative Example 3, increasing the amount of azo initiator will cause material degradation. After degradation, the molecular chains break and the performance drops sharply.

[0072] As shown in Comparative Example 4, when copolymer polypropylene is used instead of homopolymer polypropylene, the burst pressure is only 4.5 Bar, which cannot meet the pressure resistance requirements of the material.

Claims

1. A polypropylene composition, characterized in that, By weight, it includes the following components Polypropylene 29-61 parts; 1-8 parts of maleic anhydride-grafted polypropylene; 5-25 parts of acrylate elastomer; 1-6 parts of azo initiator; 35-45 parts glass fiber; Wherein, the polypropylene is selected from homopolymer polypropylene; The melt flow rate of the polypropylene is 5-30 g / 10 min, and the detection conditions are: 230℃, 2.16 kg. The grafting rate of the maleic anhydride-grafted polypropylene is 0.8-1.2%; The acrylate elastomer contains 17-30 wt% butyl acrylate. The molecular weight of the azo initiator is 150-300.

2. The polypropylene composition according to claim 1, characterized in that, The density of the maleic anhydride-grafted polypropylene is 0.900-0.915 g / cm³. 3 .

3. The polypropylene composition according to claim 1, characterized in that, The acrylate elastomer contains 20-30 wt% butyl acrylate.

4. The polypropylene composition according to claim 1, characterized in that, The azo initiator has a molecular weight of 200-300.

5. The polypropylene composition according to claim 1, characterized in that, It also includes 0-5 parts by weight of adjuvants.

6. The polypropylene composition according to claim 5, characterized in that, The additives are selected from 0-2 parts of colorant; 0-1 parts of antioxidant; and 0-1 parts of light stabilizer.

7. The polypropylene composition according to claim 6, characterized in that, The antioxidant includes a primary antioxidant and a secondary antioxidant, wherein the primary antioxidant is selected from hindered phenols and the secondary antioxidant is selected from phosphites.

8. A method for preparing a polypropylene composition according to any one of claims 1-7, characterized in that, The process includes the following steps: weighing each component except for the azo initiator according to the weight ratio and mixing them evenly in a high-speed mixer to obtain a mixture; adding the mixture to a twin-screw extruder, adding the azo initiator through side feeding, melting and mixing, extruding and granulating to obtain a polypropylene composition.

9. The use of the polypropylene composition according to any one of claims 1-7, characterized in that, Used to manufacture water purification processor components.

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