A polypropylene composite material, its preparation method and application

Abstract

This invention relates to a polypropylene composite material, its preparation method, and its applications. The polypropylene composite material, by weight, comprises the following components: 54-83 parts polypropylene resin, 4-12 parts high-density polyethylene, 10-30 parts glass fiber, 0.03-0.1 parts zinc oxide, 0.05-0.3 parts aromatic carboxylic acid, and 2-4 parts compatibilizer. The simultaneous addition of zinc oxide, specific aromatic carboxylic acids, and high-density polyethylene to the matrix containing polypropylene resin and glass fiber improves the melt strength of the polypropylene composite material, thereby avoiding melt fracture due to insufficient melt strength during blow molding. Furthermore, the simultaneous addition of zinc oxide, specific aromatic carboxylic acids, and high-density polyethylene also improves the elongation at break of the polypropylene composite material.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and more specifically, to a polypropylene composite material, its preparation method, and its application. Background Technology

[0002] Polypropylene (PP) is characterized by its wide availability, high yield, non-toxicity, odorless nature, and low density. It also possesses good heat resistance and chemical corrosion resistance, making it widely used in industries such as home appliances, automobiles, and electronics. Glass fiber reinforced polypropylene is widely used in the manufacture of various parts, with blow molding being a primary requirement for piping components. Currently, in practical applications, existing glass fiber reinforced polypropylene materials often experience cracking during blow molding due to insufficient melt strength, leading to product molding failure and other quality issues. This severely impacts molding efficiency and increases costs.

[0003] The Chinese patent for a glass fiber-filled flame-retardant polypropylene composition states that the composition can be blow-molded; however, it does not address the problem that glass fiber reinforced polypropylene composites are prone to melt fracture during blow molding due to insufficient melt strength.

[0004] Therefore, there is a need to develop a glass fiber reinforced polypropylene material that can avoid melt fracture due to insufficient melt strength during blow molding to meet market demand. Summary of the Invention

[0005] The primary objective of this invention is to overcome the problem of melt fracture caused by insufficient melt strength in existing glass fiber reinforced polypropylene composites during blow molding, and to provide a polypropylene composite material. This polypropylene composite material, by simultaneously adding zinc oxide, specific aromatic carboxylic acids, and high-density polyethylene to a matrix containing polypropylene resin and glass fiber, improves the melt strength of the polypropylene composite material, thereby avoiding melt fracture due to insufficient melt strength during blow molding. Furthermore, the simultaneous addition of zinc oxide, specific aromatic carboxylic acids, and high-density polyethylene also improves the elongation at break of the polypropylene composite material.

[0006] A further object of the present invention is to provide the application of the above-mentioned polypropylene composite material in the preparation of tubular parts.

[0007] A further object of the present invention is to provide a tubular part made by blow molding using the above-mentioned polypropylene composite material.

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

[0009] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0010] A polypropylene composite material, by weight, comprises the following components: 54-83 parts polypropylene resin, 4-12 parts high-density polyethylene, 10-30 parts glass fiber, 0.03-0.1 parts zinc oxide, 0.05-0.3 parts aromatic carboxylic acid, and 2-4 parts compatibilizer.

[0011] The molar ratio of zinc oxide to the carboxylic acid group in the aromatic carboxylic acid is 1:(1.6-2.4);

[0012] The structure of the aromatic carboxylic acid is shown in formula (I):

[0013]

[0014] In this case, R1 is a methyl group, a carboxyl group, or hydrogen, and R2 is a carboxyl group.

[0015] In this invention, R2 represents a substituent at the adjacent, para, or meta position of R1, and the number of R2 is 1.

[0016] The inventors of this invention have discovered that simultaneously adding zinc oxide, a specific aromatic carboxylic acid, and high-density polyethylene to a matrix containing polypropylene resin and glass fiber can improve the melt strength of polypropylene composite materials, thereby avoiding melt fracture due to insufficient melt strength during blow molding. Furthermore, the simultaneous addition of zinc oxide, a specific aromatic carboxylic acid, and high-density polyethylene can also improve the elongation at break of the polypropylene composite material.

[0017] The applicant speculates that the principle may be as follows: specific aromatic carboxylic acids and zinc oxide react in situ during the melting process to form aromatic carboxylic acid zinc salts or their complexes, which is beneficial to the uniform dispersion of each component and improves the melt strength and elongation at break of the polypropylene composite material to a certain extent; at the same time, the addition of high-density polyethylene helps to strengthen the entanglement of molecular chains between each component, further improving the melt strength and elongation at break of the polypropylene composite material.

[0018] Optionally, the aromatic carboxylic acid is at least one selected from phthalic acid, isophthalic acid, terephthalic acid, o-methylbenzoic acid, p-methylbenzoic acid, m-methylbenzoic acid, or benzoic acid.

[0019] Preferably, the aromatic carboxylic acid is at least one selected from phthalic acid, isophthalic acid, o-methylbenzoic acid, p-methylbenzoic acid, m-methylbenzoic acid, or benzoic acid.

[0020] More preferably, the aromatic carboxylic acid is phthalic acid.

[0021] The inventors of this invention further discovered that when the aromatic carboxylic acid is phthalic acid, the polypropylene composite material has higher melt strength.

[0022] Preferably, the melt flow rate of the high-density polyethylene at 190°C and 2.16 kg is 0.3 to 12.0 g / 10 min.

[0023] More preferably, the melt flow rate of the high-density polyethylene at 190°C and 2.16 kg is 0.35–1.00 g / 10 min. Controlling the melt flow rate of the high-density polyethylene within this range results in better melt strength and elongation at break of the polypropylene composite material.

[0024] In this invention, the melt flow rate of the high-density polyethylene can be measured according to ISO 1133-1-2021.

[0025] In the polypropylene composite material of the present invention, polypropylene resin is used as the main resin, and preferably, its content accounts for at least 40% of the mass percentage of the polypropylene composite material.

[0026] Preferably, the melt flow rate of the polypropylene resin at 230°C and 2.16 kg is ≤12 g / 10 min.

[0027] More preferably, the melt flow rate of the polypropylene resin at 230°C and 2.16 kg is 0.5–3.0 g / 10 min. Controlling the melt flow rate of the polypropylene resin within this range results in better melt strength of the polypropylene composite material.

[0028] In this invention, the melt flow rate of the polypropylene resin can be measured according to ISO 1133-1-2011.

[0029] Preferably, the polypropylene resin is one or both of copolymer polypropylene resin and homopolymer polypropylene resin.

[0030] Preferably, the compatibilizer is one or both of maleic anhydride-grafted polypropylene or glycidyl methacrylate-grafted polypropylene.

[0031] More preferably, in the maleic anhydride-grafted polypropylene, the mass grafting rate of maleic anhydride is 0.5% to 1.5%. The grafting rate is tested by acid-base titration.

[0032] More preferably, in the glycidyl methacrylate-grafted polypropylene, the glycidyl methacrylate grafting rate is 0.5% to 1.5% by mass. The grafting rate is tested by acid-base titration.

[0033] Preferably, the glass fiber has an average length of 3.0 to 4.5 mm and an average cross-sectional diameter of 10 to 13 μm.

[0034] Preferably, the glass fiber is alkali-free chopped glass fiber.

[0035] Preferably, the polypropylene composite material further includes the following components in parts by weight: 0.4 to 2 parts of other additives.

[0036] More preferably, the other additives are one or both of antioxidants and lubricants.

[0037] More preferably, the antioxidant is at least one of hindered phenolic antioxidants or phosphite antioxidants.

[0038] Specifically, the hindered phenolic antioxidants include, but are not limited to, antioxidant 1010; the phosphite antioxidants include, but are not limited to, antioxidant 168.

[0039] More preferably, the lubricant is stearate.

[0040] Specifically, the stearates include, but are not limited to, zinc stearate.

[0041] The application of the aforementioned polypropylene composite material in the preparation of tubular parts is also within the scope of protection of this invention.

[0042] The present invention also protects a tubular part made by blow molding using the above-mentioned polypropylene composite material.

[0043] Preferably, the tubular part is one or both of automotive air duct parts or automotive piping parts.

[0044] The preparation method of the above-mentioned polypropylene composite material includes the following steps: weighing and mixing each component according to the formula, performing melt extrusion, and granulation to obtain the polypropylene composite material.

[0045] Preferably, the melt extrusion is carried out in an extruder.

[0046] More preferably, the extruder is a twin-screw extruder.

[0047] More preferably, the screw speed of the extruder is 400-600 rpm, the length-to-diameter ratio of the screw is (30-45):1, and the temperature is 160-200℃.

[0048] Compared with the prior art, the beneficial effects of the present invention are:

[0049] The polypropylene composite material of the present invention improves the melt strength of the polypropylene composite material by simultaneously adding zinc oxide, specific aromatic carboxylic acids, and high-density polyethylene to a matrix containing polypropylene resin and glass fiber, thereby avoiding the problem of melt fracture due to insufficient melt strength during blow molding. Furthermore, the simultaneous addition of zinc oxide, specific aromatic carboxylic acids, and high-density polyethylene also improves the elongation at break of the polypropylene composite material. Detailed Implementation

[0050] To more clearly and completely describe the technical solution of the present invention, the present invention will be further described in detail below through specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention. Various changes can be made within the scope of the claims of the present invention.

[0051] The reagents used in the various embodiments and comparative examples of this invention are described below:

[0052] Polypropylene resin 1#: B1101, Taiwan Chemical Fiber Co., Ltd., melt flow rate at 230℃ and 2.16kg is 0.5g / 10min;

[0053] Polypropylene resin #2: HP500N, CNOOC Shell Petrochemicals Co., Ltd., melt flow rate at 230℃ and 2.16kg is 10g / 10min;

[0054] Polypropylene resin #3: PPH-T03, Maoming Petrochemical Company, melt flow rate at 230℃ and 2.16kg is 3.0g / 10min;

[0055] Glass fiber: Alkali-free chopped glass fiber, with an average length of 4.5 mm and an average cross-sectional diameter of 13 μm, ECS13-4.5-T538D, Taishan Glass Fiber;

[0056] High-density polyethylene 1#: HDPE 5000S, Yangzi Petrochemical, melt flow rate at 190℃ and 2.16kg is 1.0g / 10min;

[0057] High-density polyethylene 2#: HHM 5502LW, Maoming Petrochemical, melt flow rate at 190℃ and 2.16kg is 0.35g / 10min;

[0058] High-density polyethylene 3#: DMDA-8008, Dushanzi Petrochemical, has a melt flow rate of 7.3 g / 10 min at 190℃ and 2.16 kg.

[0059] Low-density polyethylene: HPR18H10AX, Daqing Petrochemical, melt flow rate at 190℃ and 2.16kg is 1.0g / 10min;

[0060] Aromatic carboxylic acid 1#: Phthalic acid: CAS No. 88-99-3, Aladdin Reagent Co., Ltd.;

[0061] Aromatic carboxylic acid 2#: isophthalic acid: CAS number 121-91-5, Aladdin Reagent Co., Ltd.;

[0062] Aromatic carboxylic acid 3#: o-methylbenzoic acid: CAS number 118-90-1, Aladdin Reagent Co., Ltd. Aromatic carboxylic acid 4#: p-methylbenzoic acid: CAS number 99-94-5, Aladdin Reagent Co., Ltd.

[0063] Aromatic carboxylic acid 5#: m-methylbenzoic acid: CAS No. 99-04-7, Aladdin Reagent Co., Ltd.;

[0064] Aromatic carboxylic acid 6#: Benzoic acid: CAS number 65-85-0, Aladdin Reagent Co., Ltd.;

[0065] Zinc oxide: CAS number 1314-13-2, Guangzhou Luchang Chemical Co., Ltd.;

[0066] Zinc phthalate: CAS No. 2880-85-5, Achemica, Switzerland;

[0067] Compatibilizer 1#: Maleic anhydride grafted polypropylene, with a maleic anhydride grafting rate of 1.0%, CA100, Arkema.

[0068] Compatibilizer 2#: Glycidyl methacrylate grafted polypropylene, glycidyl methacrylate grafting rate of 1.0%, PX6006, Lyon Basel Industries.

[0069] Other additives #1: Antioxidant, Antioxidant 225, commercially available;

[0070] Other additives #2: Lubricant, zinc stearate, commercially available.

[0071] Unless otherwise specified, all components (e.g., other additives 1#) used in the parallel examples and comparative examples are the same commercially available products.

[0072] The polypropylene composite materials of the various embodiments and comparative examples of the present invention are prepared by the following process: weighing and mixing each component according to the formula, performing melt extrusion, and granulation to obtain the polypropylene composite material.

[0073] The twin-screw extruder has the following temperature zones: Zone 1: 160℃, Zone 2: 160℃, Zone 3: 180℃, Zone 4: 180℃, Zone 5: 200℃, Zone 6: 200℃, Zone 7: 200℃, Zone 8: 180℃, Zone 9: 180℃, Zone 10: 200℃; the twin-screw extruder has a screw speed of 450 rpm and a screw length-to-diameter ratio of 40:1.

[0074] The performance testing methods and standards for the polypropylene composite materials of the various embodiments and comparative examples of the present invention are as follows:

[0075] (1) Melt strength: Melt strength was calculated using a melt flow rate (MFR) meter and the following formula: MS = 3.54 × 10⁵ ΔL 2 R0 / MFR230;

[0076] Where MS is melt strength (Pa·s); ΔL is the extrusion length (mm) when the extrusion diameter is reduced by 50%; R0 is the radius of the extrusion initially exposed from the die (mm); MFR230 is the MFR value (g / 10min) measured by an MFR tester at 230℃ and a load of 2.16kg.

[0077] (2) Elongation at break: The test standard is ISO-527-2012, and the test condition is 23℃.

[0078] Examples 1-14

[0079] Examples 1-14 provide a series of polypropylene composite materials, the weight parts of each component in the formulation are shown in Tables 1 and 2.

[0080] Table 1 Formulations of Examples 1-9

[0081] Example 1 2 3 4 5 6 7 8 9 Polypropylene resin #1 63 54 83 / / 63 63 63 63 Polypropylene resin #2 / / / 63 / / / / / Polypropylene resin #3 / / / / 63 / / / / Fiberglass 20 30 10 20 20 20 20 20 20 High-density polyethylene #1 10 12 5 10 10 / / 10 10 High-density polyethylene #2 / / / / / 10 / / / High-density polyethylene #3 / / / / / / 10 / / Zinc oxide 0.06 0.1 0.03 0.06 0.06 0.06 0.06 0.06 0.06 Aromatic carboxylic acid 1# 0.122 0.2 0.05 0.122 0.122 0.122 0.122 0.122 0.147 Compatibilizer 1# 3 2 4 3 3 3 3 / 3 Compatibilizer #2 / / / / / / / 3 / Other adjuvants #1 0.6 1 / 0.6 0.6 0.6 0.6 0.6 0.6 Other adjuvants #2 0.6 1 / 0.6 0.6 0.6 0.6 0.6 0.6

[0082] Table 2 Formulations of Examples 10-14

[0083] Example 10 11 12 13 14 Polypropylene resin #1 63 63 63 63 63 Fiberglass 20 20 20 20 20 High-density polyethylene #1 10 10 10 10 10 Zinc oxide 0.06 0.06 0.06 0.06 0.06 Aromatic carboxylic acid 2# 0.122 / / / / Aromatic carboxylic acids #3 / 0.201 / / / Aromatic carboxylic acid 4# / / 0.201 / / Aromatic carboxylic acids #5 / / / 0.201 / Aromatic carboxylic acid 6# / / / / 0.180 Compatibilizer 1# 3 3 3 3 3 Other adjuvants #1 0.6 0.6 0.6 0.6 0.6 Other adjuvants #2 0.6 0.6 0.6 0.6 0.6

[0084] In Example 1, the molar ratio of zinc oxide to aromatic carboxylic acid 1# is 1:1, and the molar ratio of zinc oxide to carboxylic acid groups in the aromatic carboxylic acid is 1:2.

[0085] In Example 2, the molar ratio of zinc oxide to aromatic carboxylic acid 1# is 1:1, and the molar ratio of zinc oxide to the carboxylic acid groups in the aromatic carboxylic acid is 1:2.

[0086] In Example 3, the molar ratio of zinc oxide to aromatic carboxylic acid 1# was 1:0.8, and the molar ratio of zinc oxide to carboxylic acid groups in the aromatic carboxylic acid was 1:1.6.

[0087] In Examples 4-8, the molar ratio of zinc oxide to aromatic carboxylic acid 1# is 1:1, and the molar ratio of zinc oxide to the carboxylic acid groups in the aromatic carboxylic acid is 1:2.

[0088] In Example 9, the molar ratio of zinc oxide to aromatic carboxylic acid 1# was 1:1.2, and the molar ratio of zinc oxide to the carboxylic acid groups in the aromatic carboxylic acid was 1:2.4.

[0089] In Example 10, the molar ratio of zinc oxide to aromatic carboxylic acid 2# was 1:1, and the molar ratio of zinc oxide to the carboxylic acid groups in the aromatic carboxylic acid was 1:2.

[0090] In Example 11, the molar ratio of zinc oxide to aromatic carboxylic acid 3# is 1:2, and the molar ratio of zinc oxide to the carboxylic acid group in the aromatic carboxylic acid is 1:2.

[0091] In Example 12, the molar ratio of zinc oxide to aromatic carboxylic acid 4# was 1:2, and the molar ratio of zinc oxide to the carboxylic acid groups in the aromatic carboxylic acid was 1:2.

[0092] In Example 13, the molar ratio of zinc oxide to aromatic carboxylic acid 5# was 1:2, and the molar ratio of zinc oxide to carboxylic acid groups in the aromatic carboxylic acid was 1:2.

[0093] In Example 14, the molar ratio of zinc oxide to aromatic carboxylic acid 6# was 1:2, and the molar ratio of zinc oxide to the carboxylic acid groups in the aromatic carboxylic acid was 1:2.

[0094] Comparative Examples 1-5

[0095] Comparative Examples 1 to 5 provide a series of polypropylene composite materials, the weight parts of each component in the formulation are shown in Table 3.

[0096] Table 3 shows the formulations for Comparative Examples 1–5.

[0097] Comparative Example 1 2 3 4 5 Polypropylene resin #1 63 63 63 63 63 Fiberglass 20 20 20 20 20 High-density polyethylene #1 / 10 10 / 10 Low-density polyethylene / / / 10 / Zinc oxide 0.06 / 0.06 0.06 / Aromatic carboxylic acid 1# 0.122 0.122 / 0.122 / Zinc phthalate / / / / 0.182 Compatibilizer 1# 3 3 3 3 3 Other adjuvants #1 0.6 0.6 0.6 0.6 0.6 Other adjuvants #2 0.6 0.6 0.6 0.6 0.6

[0098] The performance test results of the polypropylene composite materials of each embodiment and comparative example according to the methods mentioned above are shown in Table 4.

[0099] Table 4. Performance test results of polypropylene composite materials in each example and comparative example.

[0100]

[0101]

[0102] As shown in Table 1, the polypropylene composite material of the present invention has higher melt strength and elongation at break, wherein the melt strength is above 50 Pa·s and the elongation at break is above 5.8%.

[0103] Comparative Examples 1-3 show the differences in melt strength and elongation at break of the polypropylene composites prepared without the addition of high-density polyethylene, zinc oxide, and aromatic carboxylic acids.

[0104] In Comparative Example 4, replacing high-density polyethylene with low-density polyethylene resulted in polypropylene composite materials with lower melt strength and elongation at break.

[0105] In Comparative Example 5, instead of adding aromatic carboxylic acids and zinc oxide, zinc phthalate was added directly. Compared with Example 1, the resulting polypropylene composite material had lower melt strength and elongation at break.

[0106] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A polypropylene composite material, characterized in that, By weight, it comprises the following components: 54-83 parts polypropylene resin, 4-12 parts high-density polyethylene, 10-30 parts glass fiber, 0.03-0.1 parts zinc oxide, 0.05-0.3 parts aromatic carboxylic acid, and 2-4 parts compatibilizer; The molar ratio of zinc oxide to the carboxylic acid group in the aromatic carboxylic acid is 1:(1.6-2.4); The structure of the aromatic carboxylic acid is shown in formula (I): In this case, R1 is a methyl group, a carboxyl group, or hydrogen, and R2 is a carboxyl group.

2. The polypropylene composite material as described in claim 1, characterized in that, The aromatic carboxylic acid is at least one of phthalic acid, isophthalic acid, terephthalic acid, o-methylbenzoic acid, p-methylbenzoic acid, m-methylbenzoic acid, or benzoic acid.

3. The polypropylene composite material as described in claim 2, characterized in that, The aromatic carboxylic acid is phthalic acid.

4. The polypropylene composite material as described in claim 1, characterized in that, The melt flow rate of the high-density polyethylene at 190°C and 2.16 kg is 0.3–12.0 g / 10 min.

5. The polypropylene composite material as described in claim 1, characterized in that, The melt flow rate of the polypropylene resin at 230℃ and 2.16kg is ≤12g / 10min.

6. The polypropylene composite material as described in claim 1, characterized in that, The compatibilizer is one or both of maleic anhydride-grafted polypropylene or glycidyl methacrylate-grafted polypropylene.

7. The polypropylene composite material as described in claim 1, characterized in that, The glass fiber has an average length of 3.0–4.5 mm and an average cross-sectional diameter of 10–13 μm.

8. The polypropylene composite material as described in claim 1, characterized in that, The polypropylene composite material also includes the following components in parts by weight: 0.4 to 2 parts of other additives.

9. A tubular part made by blow molding using the polypropylene composite material described in any one of claims 1 to 8.

10. A method for preparing the polypropylene composite material according to any one of claims 1 to 8, characterized in that, The process includes the following steps: weighing and mixing each component according to the formula, performing melt extrusion, and granulation to obtain the polypropylene composite material.

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