Polypropylene composite material as well as preparation method and application thereof

Abstract

The invention relates to a polypropylene composite material as well as a preparation method and application thereof. The polypropylene composite material comprises the following components: PP resin, mineral filler, modified plant fiber, a flexibilizer, a compatilizer and an anti-aging agent. The polypropylene composite material provided by the invention has good static pressure resistance, good toughness, good aging resistance and good fiber migration resistance.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and more specifically to a polypropylene composite material and a preparation method and application thereof. Background Art

[0002] PP resin is a propylene polymer, which includes homopolymer polypropylene and copolymer polypropylene. It is widely used in home appliances, automobiles, medical treatment, energy, construction and other fields. PP resin itself has the characteristics of 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. The outer shell of household water purifier filter cartridges has a static pressure requirement of 26kgf without bursting, and conventional polypropylene materials are usually difficult to meet this requirement. The use of glass fiber for reinforcement modification can effectively improve the strength of polypropylene materials, such as patent CN103146073A. However, glass fiber reinforced PP materials inevitably have a certain degree of glass fiber exposure, which may fall off from the surface of the material during long-term use and enter the water body, causing certain water pollution. In addition, the material used for the filter cartridge housing also needs to have good aging resistance to avoid strength attenuation due to heat and other factors during long-term use, which in turn causes the filter cartridge housing to rupture under pressure.

[0004] Therefore, it is necessary to solve the problem that the existing polypropylene materials have poor static pressure resistance and aging performance, or the glass fiber reinforced polypropylene materials have glass fiber shedding and enter the water body, thereby limiting the application of polypropylene materials in household water purifier filter housings. Summary of the invention

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

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

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

[0008] The above-mentioned object of the present invention is achieved by the following technical solutions:

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

[0010]

[0011]

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

[0013] In the present invention, the addition of toughening agent improves the toughness of the material, the addition of antioxidant improves the aging resistance of the material, and the addition of mineral filler is also helpful to improve the basic mechanical properties of the material.

[0014] The inventors of the present invention have found through research that by subjecting plant fibers to specific modification and chopped short, and then adding them to polypropylene composite materials, the modified plant fibers have good compatibility with the polypropylene composite materials and, due to their fibrous characteristics, not only improve the toughness of the polypropylene composite materials, but also improve the static pressure resistance of the polypropylene composite materials. In addition, due to the specific modification, the polypropylene composite materials will not show fiber migration in the migration test.

[0015] The selection of modifiers for modified plant fibers is critical. If acetic anhydride is used for modification, the modified plant fibers will have poor compatibility with polypropylene, and the static pressure resistance will not be significantly improved, and fiber migration will occur. If the modified plant fibers are not chopped, they cannot be well wrapped by the polypropylene resin, resulting in poor performance.

[0016] In the present invention, the PP resin is used as the main resin, which accounts 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 to 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. By selecting a PP resin with this melt flow rate range, the obtained polypropylene composite material has better properties.

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

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

[0021] The mineral fillers commonly used in the art can be used in the present 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 talcum powder in a mass ratio of 1: (0.5-2). The two fillers are used in combination, and the obtained polypropylene composite material has better anti-static pressure performance.

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

[0026] Preferably, the average cross-sectional diameter of the modified plant fiber is 10 to 30 μm.

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

[0028] In the present 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 value is calculated to obtain the average diameter.

[0029] Preferably, the preparation process of the modified plant fiber is as follows: soaking the plant fiber in anhydride for 2 to 8 hours, washing, drying, and chopping to obtain the modified plant fiber.

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

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

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

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

[0034] Tougheners, compatibilizers, and antioxidants commonly used in the art can be used in the present invention.

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

[0036] More preferably, the polyolefin elastomer is at least one of POE (ethylene-octene copolymer) and 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 0.5-2 wt %.

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

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

[0042] More preferably, the other auxiliary agent is at least one of an antioxidant or a lubricant.

[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 stearic acid amide or ethylene bisstearamide.

[0045] The preparation method of the polypropylene composite material comprises 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.; the screw speed of the extruder for the melt extrusion is 400-600 rpm.

[0047] The present invention also provides the use of the polypropylene composite material in preparing household items, electronic components, household appliances, gardening equipment, medical technology equipment, motor vehicle parts or body parts.

[0048] In particular, the polypropylene composite material can be used to prepare articles having good resistance to static pressure.

[0049] In particular, the polypropylene composite material is used to prepare the outer shell of a water purifier filter element.

[0050] Compared with the prior art, the present invention has the following beneficial effects:

[0051] The polypropylene composite material of the invention has good static pressure resistance, good toughness, good aging resistance and good fiber migration resistance. DETAILED DESCRIPTION

[0052] In order to more clearly and completely describe the technical solution of the present invention, the present invention is further described in detail through specific embodiments below. It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention. Various changes can be made within the scope of the rights of the present invention.

[0053] Some of the reagents selected in the embodiments and comparative examples of the present invention are described as follows:

[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#: obtained by mixing talcum powder and calcium carbonate in a mass ratio of 1:1; wherein, the talcum powder is HTPultra 5L, Liaoning Aihaiyi Mi, with a particle size D50 of 0.65 μm; the calcium carbonate is WX6000-E1, Wuhu Weixiang Ultrafine Materials Co., Ltd., with a particle size D50 of 0.7 μm.

[0058] Mineral filler 2#: Different from mineral filler 1#, the mass ratio of talcum powder and calcium carbonate is 1:2.

[0059] Mineral filler 3#: talc powder is HTPultra 5L, Liaoning Aihaiyimi, particle size D50 is 0.65μm;

[0060] Mineral filler 4#: calcium carbonate is WX6000-E1, Wuhu Weixiang Superfine Materials Co., Ltd., particle size D50 is 0.7 μm;

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

[0062] Compatibilizer: PP-g-MAH, SK Global Chemical, CA100;

[0063] Anti-aging agent: distearyl thiodipropionate, antioxidant, commercially available;

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

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

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

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

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

[0069] Modified plant fiber 6#: homemade, basically the same as modified plant fiber 1#, except that propionic anhydride is replaced by caproic anhydride to obtain modified plant fiber 6#.

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

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

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

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

[0074] Unless otherwise specified, the components (eg, compatibilizer, antioxidant) selected in each parallel example and comparative example are the same commercially available products.

[0075] The properties of the polypropylene composite materials provided in the embodiments and comparative examples of the present invention were measured according to the following test methods:

[0076] 1. Static pressure: The materials are injection molded into filter elements using the same process. After assembly, a water pressure test is performed to record the static pressure value that causes cracking.

[0077] 2. Izod notched impact strength: in accordance with ISO 180-2019, type A notch;

[0078] 3. Aging resistance: The same 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°C 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 in accordance with ISO 527-1:2019.

[0079] 4. Migration test: Inject the material into a sample (200*10*2mm), immerse it in tap water at 23°C for 90 days, observe whether there is fiber migration in the water, and record the number.

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

[0081] According to the ratio, each component is put into a high-speed mixing machine and mixed for 5 minutes at a mixer speed of 500 r / min to obtain a mixture; the mixture is extruded and granulated through a twin-screw extruder to obtain a polypropylene composite material; wherein the temperatures of each zone of the screw are set to 130° C., 180° C., 190° C., 200° C., 210° C., 200° C., 210° C., 210° C., 210° C., and the rotation speed is 500 rpm to obtain a polypropylene composite material.

[0082] Examples 1 to 11

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

[0084] Table 1 Formulas of Examples 1 to 11 (parts by weight)

[0085]

[0087] Comparative Examples 1 to 7

[0088] Comparative Examples 1 to 7 provide a series of polypropylene composite materials, and their formulations are shown in Table 2.

[0089] Table 2 Formulas of Comparative Examples 1 to 7 (parts by weight)

[0090]

[0091]

[0092] The average length of the flax fiber A in Table 2 is 4 mm, which is obtained by directly chopping the flax fiber (manufacturer Jiapeng Flax).

[0093] The properties of the polypropylene composite materials of the embodiments and comparative examples were measured according to the above-mentioned test methods. The test results are shown in Table 3.

[0094] Table 3 Performance test results of polypropylene composite materials of various embodiments and comparative examples

[0095]

[0096]

[0098] From Table 3, we can see that:

[0099] The static pressure of the polypropylene composite materials of Examples 1 to 11 is all above 26 kgf, and the Izod notched impact strength is all above 4.0 kJ / m 2 The above results show that the aging resistance test is 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 static pressure resistance, good toughness, good aging resistance and good fiber migration resistance.

[0100] In Comparative Example 1, no modified plant fiber is added, and the static pressure resistance performance of the polypropylene composite material is poor. The modifiers of the modified plant fibers added in Comparative Examples 2 and 3 are not suitable, and the static pressure resistance performance of the polypropylene composite material is not good, and fiber migration occurs in the migration test. The modified plant fibers added in Comparative Example 4 are not chopped, and the various properties of the polypropylene composite material are not good. The plant fibers in Comparative Example 5 are not modified, and the various properties of the polypropylene composite material are not good. In Comparative Example 6, glass fiber is added, and fiber migration occurs in the migration test. The modifier of the modified plant fiber added in Comparative Example 7 is not suitable, and the static pressure resistance performance of the polypropylene composite material is not good, the aging resistance is not good, and fiber migration occurs in the migration test.

[0101] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A polypropylene composite material, characterized in that: The composition comprises the following components in parts by weight: The modified plant fiber is obtained by modifying the plant fiber with anhydride; the modified plant fiber is short-cut fiber; and the 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° C. and 2.16 kg is 2 to 15 g / 10 min.

3. The polypropylene composite material according to claim 1, characterized in that: The mineral filler is at least one of calcium carbonate or talc.

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

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

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

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

8. 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.

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

10. Use of the polypropylene composite material according to any one of claims 1 to 8 in the preparation of household items, electronic components, household appliances, gardening equipment, medical technology equipment, motor vehicle components or body parts.

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