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 comprises the following components: PP resin, mineral filler, modified plant fiber, toughening agent, compatibilizer, and antioxidant. The polypropylene composite material of this invention exhibits good hydrostatic pressure resistance, good toughness, good aging resistance, and good resistance to fiber migration.

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] PP resin is a propylene polymer, broadly classified into homopolymer polypropylene and copolymer polypropylene, and widely used in household appliances, automobiles, medical devices, energy, construction, and other fields. PP resin itself possesses characteristics such as low density, high ductility, and solvent resistance.

[0003] The advantages of PP resin make it one of the preferred materials for the outer shell of household water purifier filter cartridges. Household water purifier filter cartridge shells must withstand a static pressure of 26 kgf without bursting, a requirement that conventional polypropylene materials often struggle to meet. Using glass fiber reinforcement can effectively improve the strength of polypropylene materials, as illustrated in patent CN103146073A. However, glass fiber reinforced PP materials inevitably have some degree of exposed glass fiber, which may detach from the material surface during long-term use and enter the water, causing water pollution. Furthermore, the material used for the filter cartridge shell also needs to have good aging resistance to prevent strength degradation due to heat and other factors during long-term use, which could lead to pressure-induced cracking of the filter cartridge shell.

[0004] Therefore, it is necessary to address the problems of poor hydrostatic pressure resistance and aging performance of existing polypropylene materials, or the issue of glass fiber shedding and entering the water in glass fiber reinforced polypropylene materials, which limits the application of polypropylene materials in the filter cartridge housing of household water purifiers. Summary of the Invention

[0005] The primary objective of this invention is to overcome the problems existing in the prior art and to provide a polypropylene composite material.

[0006] A further object of the present invention is to provide a method for preparing the above-mentioned polypropylene composite material.

[0007] A further object of the present invention is to provide the application of the above-mentioned polypropylene composite material in the preparation of household goods, electronic components, household appliances, gardening equipment, medical technology equipment, motor vehicle parts or body parts.

[0008] The above-mentioned objective of the present invention is achieved through the following technical solution:

[0009] A polypropylene composite material comprising the following components in parts by weight:

[0010]

[0011]

[0012] The modified plant fiber is obtained by modifying plant fiber with acid anhydride; the modified plant fiber is short-cut fiber; the acid anhydride is at least one of propionic anhydride, butyric anhydride or valeric anhydride.

[0013] In this invention, the addition of toughening agents improves the toughness of the material, the addition of anti-aging agents improves the aging resistance of the material, and the addition of mineral fillers also helps to improve the basic mechanical properties of the material.

[0014] The inventors of this invention discovered through research that by specifically modifying and shaving plant fibers, and then adding them to polypropylene composites, the modified plant fibers exhibit good compatibility with the polypropylene composites. Furthermore, due to their fibrous nature, the modified plant fibers not only improve the toughness of the polypropylene composites but also enhance their resistance to hydrostatic pressure. In addition, due to the specific modification, this polypropylene composite does not exhibit fiber migration in migration tests.

[0015] The selection of modifiers for modified plant fibers is crucial. Using modifiers such as acetic anhydride can lead to poor compatibility between the modified plant fibers and polypropylene, resulting in minimal improvement in hydrostatic pressure resistance and potential fiber migration. Furthermore, without chopped modification, the modified plant fibers cannot be properly encapsulated by the polypropylene resin, resulting in poor overall performance.

[0016] In this invention, PP resin is used as the main resin, accounting for at least 55 wt% of the polypropylene composite material.

[0017] Preferably, the melt flow rate of the PP resin measured at 230°C and 2.16 kg is 2–15 g / 10 min.

[0018] More preferably, the melt flow rate of the PP resin measured at 230°C and 2.16 kg is 3–10 g / 10 min. Using PP resin within this melt flow rate range results in polypropylene composite materials with better overall properties.

[0019] In this invention, the melt flow rate of PP resin can be measured according to ISO 1133:2022.

[0020] Preferably, the PP resin is at least one of homopolymer PP resin or copolymer PP resin.

[0021] Commonly used mineral fillers in this field can be used in this invention.

[0022] Preferably, the particle size D50 of the mineral filler is 0.3–3 μm. The particle size D50 of the mineral filler can be measured by a particle size analyzer.

[0023] Preferably, the mineral filler is at least one of calcium carbonate or talc.

[0024] More preferably, the mineral filler comprises calcium carbonate and talc in a mass ratio of 1:(0.5-2). The combination of these two fillers results in a polypropylene composite material with better hydrostatic pressure resistance.

[0025] Preferably, the modified plant fiber has an average length of 3 to 5 mm.

[0026] Preferably, the modified plant fiber has an average cross-sectional diameter of 10–30 μm.

[0027] In this invention, the average length of the modified plant fiber can be measured by a two-dimensional measuring instrument.

[0028] In this invention, the average diameter of the cross-section of the modified plant fiber can be measured by an electron microscope. After testing the cross-sections of 200 modified plant fibers, the arithmetic mean is calculated.

[0029] Preferably, the preparation process of the modified plant fiber is as follows: the plant fiber is soaked in acid anhydride for 2 to 8 hours, washed, dried and cut into short pieces to obtain the modified plant fiber.

[0030] More preferably, the mass ratio of the plant fiber to the acid anhydride is 1:3 to 10.

[0031] More preferably, the cleaning process is as follows: wash with water 2 to 5 times, each time for 3 to 10 minutes.

[0032] More preferably, the drying temperature is 60-80°C and the time is 4-6 hours.

[0033] Preferably, the plant fiber is at least one of flax fiber or jute fiber.

[0034] Commonly used toughening agents, compatibilizers, and antioxidants in this field can all be used in this invention.

[0035] Preferably, the toughening agent includes, but is not limited to, polyolefin elastomers.

[0036] More preferably, the polyolefin elastomer is at least one of POE (ethylene-octene copolymer) or EVA (ethylene-vinyl acetate copolymer).

[0037] Preferably, the toughening agent has a melt flow rate of 0.5 to 2 g / 10 min measured at 230°C and 2.16 kg.

[0038] Preferably, the compatibilizer includes, but is not limited to, maleic anhydride-grafted polypropylene.

[0039] More preferably, the maleic anhydride grafting rate of the maleic anhydride-grafted polypropylene is 0.5 to 2 wt%.

[0040] Preferably, the antioxidant is at least one of dioctadecyl thiodipropionate or didodecyl thiodipropionate.

[0041] Preferably, the polypropylene composite material further includes 0.5 to 1.5 parts of other additives.

[0042] More preferably, the other additives are at least one of antioxidants or lubricants.

[0043] More preferably, the antioxidant is at least one of antioxidant 1010 or antioxidant 168.

[0044] More preferably, the lubricant is at least one of stearamide or ethylene bis-stearamide.

[0045] The preparation method of the above-mentioned polypropylene composite material includes the following steps: mixing the components, melt extruding, and granulating to obtain the polypropylene composite material.

[0046] Preferably, the temperature of the melt extrusion is 130–220°C; and the screw speed of the extruder for the melt extrusion is 400–600 rpm.

[0047] The present invention also provides the application of the above-mentioned polypropylene composite material in the preparation of household goods, electronic components, household appliances, gardening equipment, medical technology equipment, motor vehicle parts or vehicle body parts.

[0048] In particular, the aforementioned polypropylene composite material can be used to prepare parts with good resistance to hydrostatic pressure.

[0049] Specifically, the aforementioned polypropylene composite material is used to manufacture the outer shell of a water purifier filter element.

[0050] Compared with the prior art, the beneficial effects of the present invention are:

[0051] The polypropylene composite material of the present invention has good hydrostatic pressure resistance, good toughness, good aging resistance and good fiber migration resistance. Detailed Implementation

[0052] 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.

[0053] The reagents used in the various embodiments and comparative examples of this invention are described below:

[0054] PP resin #1: Daqing Petrochemical, T30S, melt index is 3g / 10min;

[0055] PP resin #2: K1008, Yanshan Petrochemical, melt index is 10g / 10min;

[0056] PP resin #3: HP500N, Wanhua, melt index is 12g / 10min;

[0057] Mineral filler #1: It is obtained by mixing talc powder and calcium carbonate in a mass ratio of 1:1; wherein, the talc powder is HTPultra 5L, Liaoning Aihai Yimi, with a particle size D50 of 0.65μm; the calcium carbonate is WX6000-E1, Wuhu Weixiang Ultrafine Materials Co., Ltd., with a particle size D50 of 0.7μm.

[0058] Mineral filler #2: Unlike mineral filler #1, the mass ratio of talc to calcium carbonate is 1:2.

[0059] Mineral filler #3: Talc powder is HTPultra 5L, Liaoning Aihai Yimi, with a particle size D50 of 0.65μm;

[0060] Mineral filler #4: Calcium carbonate WX6000-E1, Wuhu Weixiang Ultrafine Materials Co., Ltd., with a particle size D50 of 0.7μm;

[0061] Toughening agent 1#: POE 7467, Dow, melt index 1.2g / 10min (190℃ / 2.16kg);

[0062] Compatibilizer: PP-g-MAH, SK General Chemicals, CA100;

[0063] Antioxidant: Dioctyl thiodipropionate, an antioxidant, commercially available;

[0064] Modified plant fiber 1#: self-made, the process is as follows: flax fiber (manufacturer Jiapeng Flax) is soaked in propionic anhydride for 5 hours (the mass ratio of flax fiber to anhydride is 1:5), then washed with clean water 3 times, each time for 4 minutes, dried at 80℃ for 5 hours, and then cut to an average length of 4 mm to obtain modified plant fiber 1#.

[0065] Modified plant fiber 2#: self-made, basically the same as modified plant fiber 1#, except that propionic anhydride is replaced with butyric anhydride to obtain modified plant fiber 2#.

[0066] Modified plant fiber 3#: self-made, basically the same as modified plant fiber 1#, except that propionic anhydride is replaced with valeric anhydride to obtain modified plant fiber 3#.

[0067] Modified plant fiber #4: Self-made, basically the same as modified plant fiber #1, except that: flax fiber is replaced with jute fiber (manufacturer: Henan Xinmeiyi) to obtain modified plant fiber #4.

[0068] Modified plant fiber 5#: self-made, basically the same as modified plant fiber 1#, except that propionic anhydride is replaced with acetic anhydride to obtain modified plant fiber 5#.

[0069] Modified plant fiber 6#: self-made, basically the same as modified plant fiber 1#, except that propionic anhydride is replaced with hexanoic anhydride to obtain modified plant fiber 6#.

[0070] Modified plant fiber 7#: self-made, basically the same as modified plant fiber 1#, the difference is that it is not chopped (length distribution is between 5 and 10 cm) to obtain modified plant fiber 7#.

[0071] Modified plant fiber 8#: Self-made, basically the same as modified plant fiber 1#, except that propionic anhydride is replaced with maleic anhydride to obtain modified plant fiber 8#.

[0072] Glass fiber: Changhai, 108, with a cross-sectional diameter of 14μm and a length of 3-4mm;

[0073] Other additives #1: Lubricant, ethylene bis-stearamide, commercially available;

[0074] Unless otherwise specified, all components (e.g., compatibilizers, antioxidants) used in the parallel examples and comparative examples are the same commercially available products.

[0075] The performance of the polypropylene composite materials provided in the embodiments and comparative examples of this invention was determined according to the following test methods:

[0076] 1. Static pressure: The same process is used to injection mold the material into filter element parts. After assembly, water pressure test is performed and the static pressure value that causes cracking is recorded.

[0077] 2. Cantilever beam notched impact strength: According to ISO 180-2019, Type A notch;

[0078] 3. Aging resistance: Identical tensile specimens were divided into group A and group B. The tensile strength of group A (without aging treatment) was measured; group B was first heat-aged at 150℃ for 200h, and then the tensile strength was tested; the tensile strength retention rate was calculated to characterize the aging resistance. The tensile strength was measured according to ISO 527-1:2019.

[0079] 4. Migration test: Inject the material into a sample (200*10*2mm), immerse it in tap water, soak it at 23℃ for 90 days, observe whether there are fiber migrations in the water, and record the quantity.

[0080] The polypropylene composite materials of the embodiments and comparative examples of the present invention were prepared by the following preparation method:

[0081] According to the formula, each component is put into a high-speed mixer and mixed for 5 minutes at a speed of 500 r / min to obtain a mixture. The mixture is then extruded and granulated through a twin-screw extruder to obtain a polypropylene composite material. The temperatures of each zone of the screw are set sequentially to 130℃, 180℃, 190℃, 200℃, 210℃, 210℃, 200℃, 210℃, and 210℃, with a speed of 500 rpm to obtain the polypropylene composite material.

[0082] Examples 1-11

[0083] Examples 1-11 provide a series of polypropylene composite materials, the formulations of which are shown in Table 1.

[0084] Table 1. Formulations (parts by weight) for Examples 1-11

[0085]

[0086] Comparative Examples 1-7

[0087] Comparative Examples 1–7 provide a series of polypropylene composite materials, the formulations of which are shown in Table 2.

[0088] Table 2 shows the formulations (parts by weight) for Comparative Examples 1–7.

[0089]

[0090]

[0091] The average length of flax fiber A in Table 2 is 4 mm, which is obtained by directly cutting flax fiber (manufacturer Jiapeng Flax) into short sections.

[0092] The properties of the polypropylene composite materials of each embodiment and comparative example were determined according to the test methods mentioned above, and the test results are shown in Table 3.

[0093] Table 3. Performance test results of polypropylene composite materials in each example and comparative example.

[0094]

[0095]

[0096] As can be seen from Table 3:

[0097] The polypropylene composites in Examples 1-11 all exhibited hydrostatic compressive strengths exceeding 26 kgf and cantilever beam notched impact strengths all exceeding 4.0 kJ / m. 2The above results show that the aging resistance test results are all above 89%, and the number of fiber migrants in the migration test is 0, indicating that the polypropylene composite material of the present invention has good hydrostatic pressure resistance, good toughness, good aging resistance and good fiber migration resistance.

[0098] Comparative Example 1, without the addition of modified plant fibers, exhibited poor hydrostatic compressive strength in its polypropylene composite. Comparative Examples 2 and 3, with the addition of unsuitable modifiers for the modified plant fibers, also showed poor hydrostatic compressive strength in their polypropylene composites, and fiber migration was observed in the migration test. Comparative Example 4, with the addition of uncut modified plant fibers, resulted in poor performance of its polypropylene composite. Comparative Example 5, with unmodified plant fibers, also showed poor performance of its polypropylene composite. Comparative Example 6, which included glass fibers, showed fiber migration in the migration test. Comparative Example 7, with the addition of unsuitable modifiers for the modified plant fibers, resulted in poor hydrostatic compressive strength and aging resistance in its polypropylene composite, and fiber migration was also observed in the migration test.

[0099] 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, The components include the following parts by weight: 63-76 parts of PP resin, 15-20 parts of mineral filler 5-10 parts modified plant fiber, 2-5 parts toughening agent 2-4 parts compatibilizer Anti-aging agent 0.2~0.6 parts; The mineral filler is calcium carbonate and talc powder in a mass ratio of 1:(0.5-2); The modified plant fiber is obtained by modifying plant fiber with acid anhydride; the modified plant fiber is short-cut fiber; the acid anhydride is at least one of propionic anhydride, butyric anhydride or valeric anhydride.

2. The polypropylene composite material according to claim 1, characterized in that, The melt flow rate of the PP resin measured at 230℃ and 2.16 kg was 2~15 g / 10 min.

3. The polypropylene composite material according to claim 1, characterized in that, The plant fiber is at least one of flax fiber or hemp fiber.

4. The polypropylene composite material according to claim 1, characterized in that, The toughening agent is a polyolefin elastomer.

5. The polypropylene composite material according to claim 1, characterized in that, The antioxidant is at least one of dioctadecyl thiodipropionate or didodecyl thiodipropionate.

6. The polypropylene composite material according to claim 1, characterized in that, The compatibilizer is maleic anhydride-grafted polypropylene.

7. The polypropylene composite material according to claim 1, characterized in that, The polypropylene composite material also includes 0.5 to 1.5 parts of other additives.

8. A method for preparing the polypropylene composite material according to any one of claims 1 to 7, characterized in that, The process includes the following steps: mixing the components, melt extruding, and granulating to obtain the polypropylene composite material.

9. The use of the polypropylene composite material according to any one of claims 1 to 7 in the preparation of household goods, electronic components, household appliances, gardening equipment, medical technology equipment, motor vehicle parts or vehicle body parts.

Images