A pp / pa composition, its preparation and use

Abstract

The application belongs to the technical field of high polymer materials, and particularly relates to a PP / PA composition, a preparation method and application thereof. The PP / PA composition comprises the following components in parts by weight: 30-55 parts of polypropylene, 20-40 parts of nylon, 3-8 parts of a toughening agent, 2-6 parts of a compatilizer-1, 1-5 parts of a compatilizer-2, 0.2-1 part of a lubricant, and 0.2-2 parts of an antioxidant; the compatilizer-1 is at least one of maleic anhydride grafted PP and maleic anhydride grafted ethylene-methyl acrylate copolymer; and the compatilizer-2 is a surlyn resin. The prepared PP / PA composition can fully exert the performance of PP and PA, and realize excellent mechanical properties, extrusion molding properties and hydrolysis resistance.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a PP / PA composition, its preparation method, and its application. Background Technology

[0002] Nylon (PA) is an important engineering plastic with high strength, high toughness, excellent wear resistance and oil resistance, good chemical stability, self-lubrication, insulation, and self-extinguishing properties. It also boasts excellent processing flow properties and is widely used in the automotive, electronics, machinery, and construction industries. However, the presence of amide polar groups in nylon leads to high water absorption and poor dimensional stability, thus limiting its applications. Polypropylene (PP) is easy to process, heat-resistant, has low water absorption, and low density, making it widely used in automotive interior and exterior parts. However, its molding shrinkage is relatively large, its heat distortion temperature is not high, its impact strength is low, and it is prone to brittle fracture at low temperatures, further limiting its applications. PP and PA alloys can effectively absorb the excellent mechanical properties of nylon and the advantages of PP's low density and low water absorption. However, the compatibility between PP and nylon is relatively poor. Currently, most corrugated pipe PP / PA materials are made by adding a small amount of PA to PP and then adding compatibilizers to obtain a more compatible PP / PA material. This results in PP / PA alloys absorbing more of the advantages of PP and not fully utilizing the advantages of PA.

[0003] Patent document CN104086893A reports a PP / PA composite material suitable for automotive window washer hoses, in which polypropylene, polyamide, stabilizers, lubricants, and toughening agents are used to prepare the PP / PA composite material. The automotive window washer hose, processed by blow molding, has a corrugated middle section with smooth ends. However, the resulting composite material exhibits poor mechanical properties and hydrolysis resistance.

[0004] Patent document CN101724197A reports a PP / PA composite material for corrugated pipes and its preparation method. The PP / PA alloy material is prepared using polypropylene, nylon, compatibilizer, toughening agent, filler masterbatch, light stabilizer, heat stabilizer, and processing aids. This PP / PA alloy material exhibits high toughness, impact resistance, and high-temperature resistance, but its hydrolysis resistance is poor. Summary of the Invention

[0005] This invention aims to provide a PP / PA composition, its preparation method, and its applications. The PP / PA composition obtained by this invention can fully utilize the properties of PP and PA, achieving excellent mechanical properties, extrusion moldability, and hydrolysis resistance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: a PP / PA composition comprising the following components in parts by weight: 30-55 parts polypropylene, 20-40 parts nylon, 3-8 parts toughening agent, 2-6 parts compatibilizer-1, 1-5 parts compatibilizer-2, 0.2-1 parts lubricant, and 0.2-2 parts antioxidant; wherein compatibilizer-1 is at least one of maleic anhydride-grafted PP and maleic anhydride-grafted ethylene-methyl acrylate copolymer; and compatibilizer-2 is surlyn resin.

[0007] Preferably, the PP / PA composition comprises the following components in parts by weight: 40-45 parts polypropylene, 30-35 parts nylon, 5-6 parts toughening agent, 3-5 parts compatibilizer-1, 2-3 parts compatibilizer-2, 0.5-0.8 parts lubricant, and 0.5-1 parts antioxidant.

[0008] In the PP / PA composition of the present invention, the content of polyolefin is not less than 30 wt%.

[0009] Preferably, the polypropylene has a melt flow rate ≤2g / 10min at 230℃ and 2.16kg load, and the test standard is ISO 1133-2011.

[0010] Preferably, the nylon is PA56. This invention uses bio-based PA56 as a raw material component. Its monomer, pentanediamine, can be obtained from bio-fermentation, and its carbon emissions are significantly lower than those of PA66. Using PP and bio-based nylon PA56 to prepare window washer hose materials not only provides excellent performance but also meets carbon reduction requirements. Furthermore, PA56 has a relatively high water absorption rate; in actual use, after absorbing water, the material exhibits better toughness, and the washer hose is less prone to breakage at low temperatures.

[0011] Preferably, the intrinsic viscosity of the nylon is 2.8 to 4.0.

[0012] The intrinsic viscosity of the nylon is tested according to ISO 307-2019, using 96wt% concentrated sulfuric acid as the solvent.

[0013] Preferably, the grafting rate of the compatibilizer-1 is 0.6% to 1%.

[0014] The grafting rate of the compatibilizer-1 is tested by infrared spectroscopy. The specific steps are as follows: the sample is pressed at 150-250°C to form a film with a thickness of 0.15-0.25 mm, and then placed in an infrared spectrometer for infrared testing. The grafting rate is calculated based on the strength of the grafted material.

[0015] More preferably, the compatibilizer-1 is maleic anhydride-grafted PP.

[0016] Preferably, the surlyn resin is at least one of sodium ion surlyn resin and Zn ion surlyn resin.

[0017] More preferably, the surlyn resin is a sodium ion-type surlyn resin. Preferably, the toughening agent includes one or more of ethylene-acrylate copolymers, ethylene-acrylate salt copolymers, polyolefin elastomers, and maleic anhydride-grafted POE.

[0018] More preferably, the toughening agent is maleic anhydride-grafted POE with a grafting rate of 0.35-1%.

[0019] The grafting rate of the toughening agent is tested by infrared spectroscopy, and the specific steps are the same as above.

[0020] Preferably, the lubricant includes oxidized polyethylene wax, stearic acid, etc.

[0021] Preferably, the antioxidants include, but are not limited to, antioxidant 1010, antioxidant 1098, antioxidant PEP-36, antioxidant 168, etc.

[0022] This invention also claims protection for a method for preparing the PP / PA composition, comprising the following steps:

[0023] All components are mixed and melt-extruded into granules to obtain the PP / PA composition.

[0024] Preferably, the temperature of the melt extrusion granulation ranges from zone one to zone nine, which are 40–60°C, 150–200°C, 230–250°C, 220–250°C, 200–250°C, 200–250°C, 200–250°C, 200–250°C, and 220–250°C, respectively.

[0025] The present invention also claims protection for the use of the PP / PA composition in the preparation of automotive window washer hoses.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The PP / PA composition prepared by this invention can fully utilize the properties of PP and PA, achieving excellent mechanical properties, extrusion molding properties, and hydrolysis resistance. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional methods. Unless otherwise specified, the antioxidants and lubricants are commercially available, and the same antioxidants and lubricants are used in parallel experiments.

[0030] The raw materials used in the examples and comparative examples are shown in Table 1.

[0031] Table 1

[0032]

[0033]

[0034] Examples 1-12 and Comparative Examples 1-4

[0035] The components and weight parts of the PP / PA compositions of Examples 1-12 and Comparative Examples 1-4 are shown in Table 2.

[0036] The preparation methods of the PP / PA compositions of Examples 1-12 and Comparative Examples 1-4 include the following steps:

[0037] All components are mixed and melt extruded to granulate, thereby obtaining the PP / PA composition. The melt extrusion granulation temperatures from zone one to zone nine are 50°C, 180°C, 240°C, 230°C, 220°C, 220°C, 220°C, 220°C, and 230°C, respectively.

[0038] Table 2 shows the component amounts (parts by weight) in the examples and comparative examples.

[0039]

[0040]

[0041] Performance testing

[0042] The PP / PA compositions obtained in the examples and comparative examples were injection molded into ISO mechanical splines, and the following performance tests were conducted according to relevant standards:

[0043] Tensile strength: ISO 527-2012, test speed 50 mm / min;

[0044] Notched impact strength (Type A notch): ISO 179-2010, pendulum energy 4J;

[0045] Extrusion moldability: The extrusion processing properties of the material were verified using a torque rheometer (HAAKE RHEOMEX OS);

[0046] Excellent formability: uniform wall thickness after extrusion, with a thickness difference not exceeding 0.1 mm, and smooth extrusion.

[0047] Good formability: uniform wall thickness after extrusion, with a thickness difference exceeding 0.1 mm but not exceeding 0.2 mm; extrusion proceeds smoothly.

[0048] In terms of formability: the extruded wall thickness is relatively uniform, with a thickness difference of 0.2–0.4 mm; extrusion is smooth.

[0049] Poor formability: uneven extrusion, thickness difference greater than 0.4 mm, or inability to extrude continuously.

[0050] Hydrolysis resistance: Immerse in water and ethylene glycol solution at 80℃ for 1000 hours, and observe the appearance to judge its quality.

[0051] Good hydrolysis resistance; no defects in appearance.

[0052] Good hydrolysis resistance: no obvious defects in appearance, and cracks not exceeding 0.1mm.

[0053] Medium hydrolysis resistance: Appearance defects, cracks 0.1-0.3mm.

[0054] Poor hydrolysis resistance: Appearance defects, cracks larger than 0.3mm.

[0055] The performance test results are shown in Table 3.

[0056] Table 3

[0057]

[0058]

[0059] As can be seen from the data in Table 3, the PP / PA composition prepared in the embodiments of the present invention has excellent mechanical properties, extrusion moldability, and hydrolysis resistance. Specifically, the tensile strength can be maintained in the range of 24-30 MPa, and the notched impact strength can be maintained in the range of 55-80 MPa.

[0060] The weight percentage of polypropylene added in Comparative Examples 1 and 2 was inappropriate, resulting in poorer mechanical properties and hydrolysis resistance of the prepared compositions; in Comparative Examples 3 and 4, only a single compatibilizer was added, resulting in PP / PA compositions with inferior mechanical properties and extrusion molding performance compared to the examples.

[0061] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A PP / PA composition for automotive windshield washer hoses, characterized in that... The product comprises the following components by weight: 40-45 parts polypropylene, 30-35 parts nylon, 5-6 parts toughening agent, 3-5 parts compatibilizer-1, 2-3 parts compatibilizer-2, 0.5-0.8 parts lubricant, and 0.5-1 parts antioxidant; wherein compatibilizer-1 is maleic anhydride-grafted PP; compatibilizer-2 is surlyn resin; the polypropylene has a melt flow rate ≤2g / 10min at 230℃ and 2.16kg load, and the test standard is ISO1133-2011; the nylon is PA56, and the intrinsic viscosity of the nylon is 2.8-4.0; the toughening agent is one or more of ethylene-acrylate copolymer and maleic anhydride-grafted POE.

2. The PP / PA composition for automotive window washer hoses as described in claim 1, characterized in that, The grafting rate of the compatibilizer-1 is 0.6-1%.

3. A method for preparing a PP / PA composition for automotive window washer hoses as described in claim 1 or 2, characterized in that, Includes the following steps: All components are mixed and melt-extruded into granules to obtain the PP / PA composition.

4. The preparation method according to claim 3, characterized in that, The melt extrusion granulation temperature ranges from zone one to zone nine, which are 40~60℃, 150~200℃, 230~250℃, 220~250℃, 200~250℃, 200~250℃, 200~250℃, 200~250℃, 200~250℃, and 220~250℃, respectively.

5. The use of a PP / PA composition for automotive window washer hoses as described in claim 1 or 2 in the preparation of automotive window washer hoses.

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