A hydrophobic polypropylene composite material with excellent chemical resistance and a preparation method thereof

Abstract

This invention discloses a polypropylene composite material with excellent hydrophobic and chemical resistance properties and its preparation method. The polypropylene composite material is prepared from the following components in parts by weight: 82.2-93.1 parts polypropylene, 4-10 parts linear low-density polyethylene, 2-5 parts polyvinylidene fluoride (PVDF), 0.5-2 parts multi-walled carbon nanotubes (MWCNTs), 0.2-0.4 parts heat stabilizer, and 0.2-0.4 parts processing aid. This invention achieves hydrophobic and chemical resistance by adding PVDF, LLDPE, and MWCNTs to polypropylene, resulting in a synergistic effect. The prepared polypropylene achieves a water contact angle greater than 105 degrees and exhibits resistance to wiping with chemicals such as gasoline and engine oil without whitening, thus expanding the application range of polypropylene.

Description

Technical Field

[0001] This invention relates to the field of polymer material modification technology, specifically to a polypropylene composite material with excellent hydrophobic and chemical resistance properties and its preparation method. Background Technology

[0002] Polypropylene, as a general-purpose plastic, is widely used in materials across various fields, particularly in home appliances and electrical appliances. Polypropylene is used in plastic parts for appliance casings, bathroom products, and medical devices. However, it is prone to bacterial growth under prolonged contact with water. If the material has good hydrophobic properties, it will not easily trap water and prevent bacterial growth. With the improvement of people's living standards and increasing attention to health issues, there is a greater demand for the preparation of functionalized polypropylene.

[0003] On the other hand, during the use of the product, it is inevitable that it will come into contact with chemicals such as oil and cleaning agents. Traditional polypropylene materials have poor chemical resistance. In the long run, the originally shiny product will be corroded and become hazy and white, which will greatly affect the product appearance and the customer's user experience. Summary of the Invention

[0004] To address the problems in the prior art, the purpose of this invention is to provide a polypropylene composite material with excellent hydrophobic and chemical resistance properties and its preparation method. The polypropylene composite material prepared by this invention is not only hydrophobic but also has excellent chemical resistance, exhibiting good corrosion resistance even against highly destructive chemicals such as gasoline and kerosene.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A hydrophobic and chemically resistant polypropylene composite material is prepared from the following components in parts by weight:

[0007]

[0008] in:

[0009] The polypropylene has a melt flow index of 3-120 g / 10 min under test conditions of 230℃ and 2.16 kg.

[0010] The linear low-density polyethylene is prepared using a metallocene catalyst, and its melt index is 5-30 g / 10 min under the test conditions of 2.16 kg at 190 °C.

[0011] The diameter of the multi-walled carbon nanotubes is 10-20 nm.

[0012] The heat stabilizer is at least one of the following: phenols, amines, phosphites, semi-hindered phenols, complexes of acryloyl functional groups and thioesters, and calixarene heat stabilizers.

[0013] The processing aid is at least one of calcium stearate, zinc stearate, and erucamide.

[0014] This invention also discloses a method for preparing the above-mentioned polypropylene composite material with excellent hydrophobic and chemical resistance properties, comprising the following steps:

[0015] Polypropylene, linear low-density polyethylene, polyvinylidene fluoride, multi-walled carbon nanotubes, heat stabilizers, and processing aids are mixed uniformly according to a specified ratio. The resulting mixture is then added to a twin-screw extruder for melt mixing and dispersion, followed by extrusion granulation to obtain a polypropylene composite material with excellent hydrophobic and chemical resistance properties. Preferably, the processing temperature of the twin-screw extruder is 200-230℃, and the aspect ratio is 36-40:1.

[0016] Compared with the prior art, the beneficial effects of the present invention are reflected in:

[0017] (1) The present invention uses linear low-density polyethylene, polyvinylidene fluoride and multi-walled carbon nanotubes as hydrophobic and chemically resistant modifiers. The raw materials are simple, readily available and reasonably priced. The materials are prepared by twin-screw melt blending. The process is simple and inexpensive, and suitable for large-scale industrial production.

[0018] (2) Polyvinylidene fluoride (PVDF) itself has very low surface activity and a fluorine-containing surface structure, which gives it hydrophobic properties. By using linear low-density polyethylene (LLDPE) as a modifier, the compatibility between PVDF and the matrix polypropylene can be increased. Furthermore, the use of LLDPE with a higher melt index as a modifier provides better flowability and allows it to carry PVDF to fill the internal defects and voids and the surface of the modified polypropylene. This prevents chemical reagents from penetrating into the matrix of the polypropylene material when the material comes into contact with them. Polyethylene has a more regular main chain structure and better resistance to chemical reagents. At the same time, the addition of PVDF and LLDPE can make the modified polypropylene hydrophobic and give it a larger water contact angle, making it less likely for chemical reagents to enter the matrix and further increasing the chemical resistance of the material.

[0019] (3) Multi-walled carbon nanotubes are nanomaterials. When added in small amounts, on the one hand, the nanomaterials themselves can promote the crystallization properties of polypropylene and increase the crystallinity. On the other hand, the sheet-like multi-walled carbon nanotubes can be distributed in the polypropylene matrix without affecting the surface smoothness of the product, thus playing a role in blocking chemicals. Detailed Implementation

[0020] The present invention will be further described below with reference to embodiments, so that those skilled in the art can better understand and implement the present invention, but the embodiments are not intended to limit the present invention.

[0021] In addition, unless otherwise specified, the preparation processes in the following embodiments are all conventional methods in the prior art, and therefore will not be described in detail; the parts in the following embodiments refer to parts by weight.

[0022] The reagents used in this embodiment and their suppliers are as follows:

[0023] The polypropylene grade is PP BX3800 (SK Chemicals, South Korea).

[0024] The linear low-density polyethylene grade is MLLDPE 1018MA (ExxonMobil).

[0025] The reagents described above are only for illustrating the source and composition of the reagents used in the experiments of this invention, so as to fully disclose the information, and do not imply that the invention cannot be achieved by using other similar reagents or reagents provided by other suppliers; other raw materials used in the examples are all conventional commercially available materials.

[0026] Example 1:

[0027] A method for preparing a polypropylene composite material with excellent hydrophobic and chemical resistance includes the following steps:

[0028] Mix 89.4 parts of polypropylene, 6 parts of linear low-density polyethylene (LLDPE), 3 parts of polyvinylidene fluoride (PVDF), 1 part of multi-walled carbon nanotubes (MWCNTs), 0.1 parts of heat stabilizer 1010 (BASF), 0.2 parts of heat stabilizer 168 (BASF), and 0.3 parts of processing aid silicone masterbatch E525 (Evonik, Germany). Then, melt-mix and disperse the mixture in a twin-screw extruder with an aspect ratio of 38:1 under the following conditions: zone 1 temperature 170℃, zone 2 temperature 230℃, zone 3 temperature 230℃, zone 4 temperature 230℃, zone 5 temperature 230℃, zone 6 temperature 230℃, and die head temperature 230℃. Extrusion and granulation will yield a polypropylene composite material with excellent hydrophobic and chemical resistance properties.

[0029] Example 2:

[0030] A method for preparing a polypropylene composite material with excellent hydrophobic and chemical resistance includes the following steps:

[0031] Mix 86 parts of polypropylene, 8 parts of linear low-density polyethylene (LLDPE), 4 parts of polyvinylidene fluoride (PVDF), 1.5 parts of multi-walled carbon nanotubes (MWCNTs), 0.1 parts of heat stabilizer 1010 (BASF), 0.2 parts of heat stabilizer 168 (BASF), and 0.2 parts of processing aid calcium stearate according to the specified ratio. Then, add the mixture to a twin-screw extruder with an aspect ratio of 36:1. The extrusion temperature is set at 170℃ in zone 1, 230℃ in zone 2, 230℃ in zone 3, 230℃ in zone 4, 230℃ in zone 5, 230℃ in zone 6, and 230℃ in the die head. The mixture is then melt-mixed and dispersed, and extruded and granulated to obtain a polypropylene composite material with excellent hydrophobic and chemical resistance properties.

[0032] Example 3:

[0033] A method for preparing a polypropylene composite material with excellent hydrophobic and chemical resistance includes the following steps:

[0034] The raw materials are mixed according to the following ratio: 87.1 parts of polypropylene, 7 parts of linear low-density polyethylene (LLDPE), 4 parts of polyvinylidene fluoride (PVDF), 1.2 parts of multi-walled carbon nanotubes (MWCNTs), 0.2 parts of heat stabilizer 1010 (BASF), 0.2 parts of heat stabilizer 1076 (BASF), and 0.3 parts of processing aid silicone masterbatch E525 (Evonik, Germany). The mixture is then fed into a twin-screw extruder with an aspect ratio of 40:1. The temperatures in zones 1, 2, 3, 4, 5, and 6 are 170°C, and the die head temperature is 230°C. The mixture is then melt-mixed and dispersed, extruded, and granulated to obtain a polypropylene composite material with excellent hydrophobic and chemical resistance properties.

[0035] Example 4:

[0036] A method for preparing a polypropylene composite material with excellent hydrophobic and chemical resistance includes the following steps:

[0037] The raw materials are mixed according to the following ratio: 93.1 parts polypropylene, 4 parts linear low-density polyethylene (LLDPE), 2 parts polyvinylidene fluoride (PVDF), 0.5 parts multi-walled carbon nanotubes (MWCNTs), 0.2 parts heat stabilizer 168 (BASF), and 0.2 parts processing aid calcium stearate. The mixture is then fed into a twin-screw extruder with a length-to-diameter ratio of 36:1. The mixture is melt-mixed and dispersed under the following conditions: zone 1 temperature 170℃, zone 2 temperature 230℃, zone 3 temperature 230℃, zone 4 temperature 230℃, zone 5 temperature 230℃, zone 6 temperature 230℃, and die head temperature 230℃. After extrusion and granulation, a polypropylene composite material with excellent hydrophobic and chemical resistance can be obtained.

[0038] Example 5:

[0039] A method for preparing a polypropylene composite material with excellent hydrophobic and chemical resistance includes the following steps:

[0040] The raw materials are mixed according to the following ratio: 82.2 parts of polypropylene, 10 parts of linear low-density polyethylene (LLDPE), 5 parts of polyvinylidene fluoride (PVDF), 2 parts of multi-walled carbon nanotubes (MWCNTs), 0.2 parts of heat stabilizer 1010 (BASF), 0.2 parts of heat stabilizer 168 (BASF), and 0.4 parts of processing aid silicone masterbatch E525 (Evonik, Germany). The mixture is then fed into a twin-screw extruder with an aspect ratio of 40:1. The extrusion is carried out under the following conditions: zone 1 temperature 170℃, zone 2 temperature 230℃, zone 3 temperature 230℃, zone 4 temperature 230℃, zone 5 temperature 230℃, and die head temperature 230℃. The mixture is then extruded and granulated to obtain a polypropylene composite material with excellent hydrophobic and chemical resistance properties.

[0041] Comparative Example 1:

[0042] A method for preparing a polypropylene composite material includes the following steps:

[0043] 92.4 parts of polypropylene, 6 parts of linear low-density polyethylene (LLDPE), 1 part of multi-walled carbon nanotubes (MWCNTs), 0.1 parts of heat stabilizer 1010 (BASF), 0.2 parts of heat stabilizer 168 (BASF), and 0.3 parts of processing aid silicone masterbatch E525 (Evonik, Germany) were mixed according to the specified ratio and then fed into a twin-screw extruder with an aspect ratio of 38:1. The extrusion mixture was then melt-mixed and dispersed under the following conditions: zone 1 temperature 170℃, zone 2 temperature 230℃, zone 3 temperature 230℃, zone 4 temperature 230℃, zone 5 temperature 230℃, zone 6 temperature 230℃, and die head temperature 230℃. The mixture was then extruded and granulated to obtain a polypropylene composite material with excellent hydrophobic and chemical resistance properties.

[0044] Comparative Example 2:

[0045] A method for preparing a polypropylene composite material includes the following steps:

[0046] 95.4 parts of polypropylene, 3 parts of polyvinylidene fluoride (PVDF), 1 part of multi-walled carbon nanotubes (MWCNTs), 0.1 parts of heat stabilizer 1010 (BASF), 0.2 parts of heat stabilizer 168 (BASF), and 0.3 parts of processing aid silicone masterbatch E525 (Evonik, Germany) were mixed according to the specified ratio and then fed into a twin-screw extruder with an aspect ratio of 38:1. The extrusion temperature was set at 170℃ in zone 1, 230℃ in zone 2, 230℃ in zone 3, 230℃ in zone 4, 230℃ in zone 5, 230℃ in zone 6, and 230℃ in the die head. The mixture was then melt-mixed and dispersed, and extruded and granulated to obtain a polypropylene composite material with excellent hydrophobic and chemical resistance properties.

[0047] Comparative Example 3:

[0048] A method for preparing a polypropylene composite material includes the following steps:

[0049] 90.4 parts of polypropylene, 6 parts of linear low-density polyethylene (LLDPE), 3 parts of polyvinylidene fluoride (PVDF), 0.1 parts of heat stabilizer 1010 (BASF), 0.2 parts of heat stabilizer 168 (BASF), and 0.3 parts of processing aid silicone masterbatch E525 (Evonik, Germany) were mixed according to the specified ratio and then fed into a twin-screw extruder with an aspect ratio of 38:1. The extrusion mixture was then melt-mixed and dispersed under the following conditions: zone 1 temperature 170℃, zone 2 temperature 230℃, zone 3 temperature 230℃, zone 4 temperature 230℃, zone 5 temperature 230℃, zone 6 temperature 230℃, and die head temperature 230℃. The mixture was then extruded and granulated to obtain a polypropylene composite material with excellent hydrophobic and chemical resistance properties.

[0050] Comparative Example 4:

[0051] A method for preparing a polypropylene composite material includes the following steps:

[0052] Mix 99.4 parts of polypropylene, 0.1 parts of heat stabilizer 1010 (BASF), 0.2 parts of heat stabilizer 168 (BASF), and 0.3 parts of processing aid silicone masterbatch E525 (Evonik, Germany) according to the specified ratio. Then, add the mixture to a twin-screw extruder with an aspect ratio of 38:1. The temperatures in zones 1, 2, 3, 4, 5, and 6 are 170°C, and the die head temperature is 230°C. The mixture is then melt-mixed and dispersed, extruded, and granulated to obtain a polypropylene composite material with excellent hydrophobic and chemical resistance properties.

[0053] Results analysis:

[0054] Water contact angle test: The water contact angle of the material surface is tested according to GB / T 30693-2014 standard.

[0055] To simulate wear after use, the gauze was abraded back and forth 10,000 times under a pressure of 10N, and the water contact angle of the material after wear was tested using the same method. The results are shown in Table 1.

[0056] Chemical resistance test: According to ES-X83239-4.16, load: 4.9N, friction cloth: white gauze, stroke: 50mm, number of friction cycles: 20 reciprocations. Test reagents: glass cleaner, neutral detergent, gasoline, kerosene.

[0057] Table 1

[0058]

[0059] The modified polypropylene material prepared by this invention has a larger water contact angle than traditional polypropylene materials, i.e., better hydrophobicity and better chemical resistance.

[0060] The above description of the embodiments is provided to enable those skilled in the art to understand and apply the present invention. It will be apparent to those skilled in the art that various modifications can be made to the embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the embodiments described herein, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A polypropylene composite material with excellent hydrophobic and chemical resistance properties, characterized in that: It is prepared from the following components in parts by weight: Polypropylene 82.2-93.1 parts, 4-10 parts of linear low-density polyethylene 2-5 parts of polyvinylidene fluoride 0.5-2 parts of multi-walled carbon nanotubes, Heat stabilizer 0.2-0.4 parts, Processing aids: 0.2-0.4 parts; The linear low-density polyethylene is a linear low-density polyethylene prepared with a metallocene catalyst, and its melt index is 5-30 g / 10 min under the test conditions of 190℃ and 2.16 kg. The diameter of the multi-walled carbon nanotubes is 10-20 nm; The processing aid is at least one of calcium stearate, zinc stearate, and erucamide.

2. The polypropylene composite material with excellent hydrophobic and chemical resistance according to claim 1, characterized in that: The polypropylene has a melt flow index of 3-120 g / 10 min under test conditions of 230℃ and 2.16 kg.

3. The polypropylene composite material with excellent hydrophobic and chemical resistance according to claim 1, characterized in that: The heat stabilizer is at least one of the following: phenols, amines, phosphites, complexes of acryloyl functional groups and thioesters, and calixarenes.

4. The method for preparing the polypropylene composite material with excellent hydrophobic and chemical resistance as described in any one of claims 1 to 3, characterized in that: Includes the following steps: Polypropylene, linear low-density polyethylene, polyvinylidene fluoride, multi-walled carbon nanotubes, heat stabilizers, and processing aids are mixed evenly according to the specified ratio. The resulting mixture is then added to a twin-screw extruder for melt mixing and dispersion, followed by extrusion granulation to obtain a polypropylene composite material with excellent hydrophobic and chemical resistance properties.

5. The method for preparing the polypropylene composite material with excellent hydrophobic and chemical resistance according to claim 4, characterized in that: The twin-screw extruder has a processing temperature of 200-230℃ and a length-to-diameter ratio of 36-40:1.

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