Polyolefin material as well as preparation method and application thereof

Abstract

The invention discloses a polyolefin material as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The polyolefin material comprises the following components in parts by mass: 45-70 parts of polypropylene resin, 8-25 parts of polyethylene resin, 3-10 parts of a flexibilizer, 8-18 parts of glass fibers, 8-18 parts of a filler, 0-1 part of a lubricant and 0-0.5 part of an antioxidant. The polyolefin material does not contain a compatilizer; the polypropylene resin is homo-polypropylene resin; according to the polyolefin material disclosed by the invention, specific components are compounded, so that the mechanical strength of the polyolefin material is ensured, the shrinkage rate is reduced, the glossiness is improved, buckling deformation of an injection molded part of the polyolefin material is reduced, and the service life of the injection molded part is prolonged. The problems of buckling deformation, low glossiness, low toughness and the like of a traditional glass fiber reinforced polypropylene material are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a polyolefin material and a preparation method and application thereof. Background Art

[0002] ABS resin (acrylonitrile-styrene-butadiene copolymer) is a thermoplastic polymer material with high strength, good toughness and easy processing and molding. It is often used to prepare the shells of home appliances. However, the temperature resistance of ABS resin is poor, which limits its application in some home appliances that need to work in high temperature environments. Polypropylene (PP) is one of the five general-purpose resins. It has excellent properties such as light weight, easy processing, and resistance to chemical corrosion. It is widely used in industrial fields such as chemicals, electrical appliances, and packaging. It is one of the materials that can replace ABS resin in the field of home appliances. However, polypropylene itself needs to be modified to meet the requirements of mechanical strength equivalent to that of ABS materials. Among them, glass fiber reinforced polypropylene is an important modification method. Glass fiber modification enables polypropylene materials to replace ABS materials in home appliances.

[0003] However, although glass fiber reinforced polypropylene is comparable to ABS material in terms of strength, it has problems such as warping, low gloss and low toughness. Summary of the invention

[0004] The present invention aims to solve at least one of the above-mentioned technical problems existing in the prior art. To this end, the object of the present invention is to provide a polyolefin material, in which a compatibilizer is omitted from the formula, and a polyolefin material with high gloss, low shrinkage and low warpage is obtained by synergistically preparing various components and their amounts.

[0005] A second aspect of the present invention provides a method for preparing a polyolefin material.

[0006] The third aspect of the present invention provides an application of a polyolefin material.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A polyolefin material, comprising the following components by weight:

[0009] 45-70 parts of polypropylene resin, 8-25 parts of polyethylene resin, 3-10 parts of toughening agent, 8-18 parts of glass fiber, 8-18 parts of filler, 0-1 part of lubricant, 0-0.5 part of antioxidant;

[0010] The polyolefin material does not contain a compatibilizer;

[0011] The polypropylene resin is a homopolymer polypropylene resin; and the polyethylene resin is a low-density polyethylene resin.

[0012] Generally speaking, the addition of compatibilizers is beneficial to improving the rigidity of materials. However, it has been found in the present invention that in a polyolefin material system, the compatibilizer acts as a bridge between polypropylene resin and glass fiber to connect the glass fiber and polypropylene resin, restricting the dispersion of glass fiber, resulting in severe anisotropy and obvious warping of the obtained polyolefin material. In the polyolefin material of the present invention, no compatibilizer is added. In the system, the glass fiber does not need to be bonded to polypropylene, and the dispersion is improved, better playing the role of improving the rigidity of the polyolefin material and reducing the shrinkage rate, and weakening the anisotropy, significantly improving the warping deformation. At the same time, the present invention uses homopolypropylene resin and low-density polyethylene resin, which is beneficial to improving the gloss. This is because the homopolypropylene resin itself has a relatively high gloss, while the low-density polyethylene resin has a relatively low crystallinity, which can affect the crystallization of the polypropylene material to improve the gloss of the polyolefin material, and the low-density polyethylene resin also has a relatively high gloss. The compounding of the two resins is beneficial to improving the gloss of the polyolefin material.

[0013] In addition, the present invention also regulates the dosages of various components. Through the compounding of different components and the optimization of dosages, the gloss, shrinkage rate, warping deformation and mechanical strength of the polyolefin material are balanced.

[0014] Specifically, the compatibilizer includes common compatibilizers such as maleic anhydride grafted polypropylene.

[0015] Preferably, the polyolefin material comprises the following components in parts by mass:

[0016] 50 - 60 parts of polypropylene resin, 10 - 15 parts of polyethylene resin, 4 - 8 parts of toughening agent, 10 - 15 parts of glass fiber, 10 - 15 parts of filler, 0.5 - 1 part of lubricant, 0.2 - 0.5 part of antioxidant.

[0017] Preferably, the melt index of the polypropylene resin at 230 °C under a load of 2.16 kg is 25 - 100 g / 10 min.

[0018] The present invention selects a high-flow polypropylene resin with a melt index ≥ 25 g / 10 min, which can better drive the glass fiber to flow in all directions, further reducing the anisotropy caused by insufficient dispersion of the glass fiber, thereby further reducing the warping deformation of the polyolefin material.

[0019] More preferably, the melt index of the polypropylene resin at 230 °C under a load of 2.16 kg is 25 - 85 g / 10 min.

[0020] Even more preferably, the melt index of the polypropylene resin at 230 °C under a load of 2.16 kg is 25 - 75 g / 10 min.

[0021] Preferably, the polypropylene resin has a flexural modulus of 1300 to 2500 MPa.

[0022] The polypropylene resin of the present invention selects a polypropylene resin with a flexural modulus ≥ 1300 MPa. A higher flexural modulus is beneficial to improving the flexural modulus of the polyolefin material and enhancing the rigidity of the material.

[0023] More preferably, the polypropylene resin has a flexural modulus of 1300 to 2000 MPa.

[0024] Even more preferably, the polypropylene resin has a flexural modulus of 1300 to 1500 MPa.

[0025] Preferably, the polyethylene resin has a melt index of 50 to 150 g / 10 min at 190 °C under a load of 2.16 kg.

[0026] More preferably, the polyethylene resin has a melt index of 50 to 100 g / 10 min at 190 °C under a load of 2.16 kg.

[0027] Even more preferably, the polyethylene resin has a melt index of 50 to 85 g / 10 min at 190 °C under a load of 2.16 kg.

[0028] Preferably, the polyethylene resin has an Izod notched impact strength of 300 to 900 J / m.

[0029] More preferably, the polyethylene resin has an Izod notched impact strength of 300 to 750 J / m.

[0030] Even more preferably, the polyethylene resin has an Izod notched impact strength of 350 to 650 J / m.

[0031] The present invention selects a polyethylene resin with a melt index not less than 50 g / 10 min and an Izod notched impact strength not less than 300 J / m, which is beneficial to improving the impact strength of the polyolefin material. At the same time, an appropriate melt index helps to ensure the gloss of the polyolefin material and reduce warpage deformation.

[0032] Preferably, the toughening agent is a polyolefin elastomer (POE); the toughening agent includes at least one of ethylene-butene copolymer and ethylene-octene copolymer.

[0033] Preferably, the toughening agent has a melt index of 0.1 to 2 g / 10 min at 190 °C under a load of 2.16 kg.

[0034] The present invention finds that choosing a toughening agent with a melt index ≤ 2 g / 10 min has a higher toughening effect, and the melt strength of the toughening agent itself is higher, which is beneficial to improving the bending resistance of the polyolefin material and enhancing the toughness of the polyolefin material.

[0035] Further preferably, the melt index of the toughening agent at 190 °C and a load of 2.16 kg is 0.1 - 1 g / 10 min.

[0036] Preferably, the glass fiber includes at least one of chopped glass fiber and continuous roving.

[0037] Preferably, the wire diameter of the glass fiber is 10 - 30 μm.

[0038] Further preferably, the wire diameter of the glass fiber is 10 - 15 μm.

[0039] The present invention finds that choosing a glass fiber with a wire diameter of 10 - 30 μm is beneficial to the full dispersion of the glass fiber in the polyolefin material system, thereby further improving the rigidity of the polyolefin material, reducing the shrinkage rate, and the obtained polyolefin material can be normally injection-molded using an injection mold for ABS material, reducing the cost of re-opening the mold during the production process.

[0040] Preferably, the filler is barium sulfate.

[0041] Preferably, the whiteness of the filler ≥ 98%.

[0042] Preferably, the average particle size of the filler is 0.1 - 10 μm.

[0043] Further preferably, the average particle size of the filler is 2 - 8 μm.

[0044] More preferably, the average particle size of the filler is 4 - 6 μm.

[0045] The present invention selects barium sulfate with high whiteness and low particle size as the filler. On the one hand, it is beneficial to improve the gloss and whiteness of the polyolefin material, reduce the shrinkage rate and production cost of the polyolefin material. On the other hand, when adding a specific filler to the polyolefin material for preparing injection-molded parts, during the injection molding process, the filler can fill the voids between the polypropylene resin, polyethylene resin and glass fiber, which is beneficial to reducing the warpage deformation of the polyolefin material.

[0046] Preferably, the lubricant includes at least one of polyethylene wax and polar wax.

[0047] Further preferably, the lubricant includes polyethylene wax and polar wax; the mass ratio of the polyethylene wax to the polar wax is 1:(1 - 3).

[0048] By adding specific lubricants, the present invention can improve the internal and external lubricity of polyolefin materials, enhance the melt fluidity, reduce the demolding force, disperse glass fibers more effectively, improve the glossiness of the surface of polyolefin materials, and due to the reduced cost of the lubricants used, it helps to balance the economy.

[0049] Preferably, the antioxidant includes at least one of hindered phenol antioxidants and phosphite antioxidants.

[0050] More preferably, the antioxidant is a compound antioxidant of hindered phenol antioxidants and phosphite antioxidants.

[0051] The second aspect of the present invention provides a method for preparing the polyolefin material described in the first aspect of the present invention, comprising the following steps:

[0052] Mix, melt, and extrude the components to obtain the polyolefin material described.

[0053] Preferably, the method for preparing the polyolefin material includes the following steps:

[0054] Mix polypropylene resin, polyethylene resin, toughening agent, filler, lubricant, and antioxidant, add them into a twin-screw extruder from the main feed port, add glass fibers from the side feed port or exhaust port, after mixing and melting, extrude and pelletize through the twin-screw extruder to obtain the polyolefin material described.

[0055] Preferably, the temperature of extrusion is 200 - 250 °C.

[0056] More preferably, the temperature of extrusion is 200 - 230 °C.

[0057] The third aspect of the present invention provides an application of the polyolefin material described in the first aspect of the present invention in the preparation of household electrical appliances.

[0058] The polyolefin material obtained by the present invention not only has mechanical strength equivalent to or higher than that of ABS materials, with good rigidity and toughness, but also solves the problems of warpage deformation and low glossiness existing in traditional glass fiber-reinforced polypropylene materials, and has the advantages of high glossiness, low shrinkage rate, low warpage deformation, and high strength, and can be used in the preparation of household electrical appliances.

[0059] Compared with the prior art, the beneficial effects of the present invention are:

[0060] 1) In the polyolefin material provided by the present invention, no compatibilizer is added. Homopolypropylene and low-density polyethylene are used simultaneously. By compounding different components and adjusting the dosages, while ensuring the mechanical strength of the polyolefin material, the shrinkage rate is reduced, the glossiness is improved, and the warpage deformation of the injection-molded parts of the polyolefin material is reduced, solving the problems of warpage deformation, low glossiness, and low toughness existing in the traditional glass fiber-reinforced polypropylene material.

[0061] 2) By further selecting polypropylene resins, polyethylene resins with specific parameters, as well as specific toughening agents and fillers, the present invention further improves the warpage deformation of the polyolefin material, enhances the rigidity and toughness of the polyolefin material, and enables the polyolefin material to have higher glossiness and lower shrinkage rate. Its mechanical strength also reaches a level equivalent to or even higher than that of the traditional ABS material. The glossiness (60°) of the obtained polyolefin resin is not lower than 60%, the flat warpage height is lower than 1.5 mm, the shrinkage rate does not exceed 0.7%, the tensile strength is not lower than 29 MPa, the flexural modulus is not lower than 2600 MPa, the impact strength is not lower than 110 J / m. At the same time, the water absorption rate is low. Compared with the ABS material, there is no need to dry the material before injection molding and no serious water streaks will appear, and the heat resistance is also better, and the heat distortion temperature reaches above 135 °C, significantly higher than that of the ABS material (generally about 80 °C).

[0062] 3) The preparation method of the polyolefin material provided by the present invention is simple, easy to realize large-scale production, and the product quality is stable and the production cost is low.

[0063] 4) The polyolefin material obtained by the present invention not only has mechanical strength equivalent to or higher than that of the ABS material, good rigidity and toughness, but also solves the problems of warpage deformation and low glossiness existing in the traditional glass fiber-reinforced polypropylene material, and has the advantages of high glossiness, low shrinkage rate, low warpage deformation and high strength, and can be used in the preparation of household electrical appliance products, especially suitable for preparing the outer shells of household electrical appliance products. Specific Embodiments

[0064] The content of the present invention will be further described in detail through specific examples below. Unless otherwise specified, the raw materials, reagents or devices used in the examples and comparative examples can be obtained from conventional commercial channels, or can be obtained by existing technical methods. Unless otherwise specified, the test or testing methods are all conventional methods in the art.

[0065] The raw materials used in the following examples and comparative examples of the present invention are described as follows:

[0066] Polypropylene resin 1: PP Z30S, Maoming Petrochemical, melt index 28 g / 10 min (230 °C / 2.16 Kg), flexural modulus 1400 MPa;

[0067] Polypropylene resin 2: PP PPH-G70T, from Juzhengyuan, melt index 70 g / 10 min (230 °C / 2.16 Kg), flexural modulus 1500 MPa;

[0068] Polypropylene resin 3: PP EP548R, from CNOOC and Shell, melt index 28 g / 10 min (230 °C / 2.16 Kg), flexural modulus 1050 MPa;

[0069] Polyethylene resin 1: LDPE MG70, from Qatargas, melt index 70 g / 10 min (190 °C / 2.16 Kg), Izod impact strength (notched) 350 J / m;

[0070] Polyethylene resin 2: LDPE 2420H, from Maoming Petrochemical, melt index 2.0 g / 10 min (190 °C / 2.16 Kg), Izod impact strength (notched) 600 J / m;

[0071] Polyethylene resin 3: LLDPE M2320, from Maoming Petrochemical, melt index 20 g / 10 min (190 °C / 2.16 Kg), Izod impact strength (notched) 600 J / m;

[0072] Polyethylene resin 4: HDPE 5502, from Maoming Petrochemical, melt index 0.3 g / 10 min (190 °C / 2.16 Kg), Izod impact strength (notched) 600 J / m;

[0073] Toughening agent 1: POE 9061, from ExxonMobil, melt index 0.5 g / 10 min (190 °C / 2.16 Kg);

[0074] Toughening agent 2: POE 8150, from Dow Chemical, melt index 0.5 g / 10 min (190 °C / 2.16 Kg);

[0075] Toughening agent 3: POE 6202, from ExxonMobil, melt index 9.1 g / 10 min (190 °C / 2.16 Kg);

[0076] Filler 1: Barium sulfate, from Haiyang Powder, HY-A08, whiteness 98%, average particle size 5 μm;

[0077] Filler 2: Talc powder, from Haiyang Powder, HY-TA08, whiteness 90%, average particle size 5 μm;

[0078] Filler 3: Calcium carbonate, from Foshan Zhongbo Chemical, whiteness 95%, average particle size 5 μm;

[0079] Compatibilizer: KT-1, from Shenyang Ketong;

[0080] Chopped glass fiber: TCR438G-13-4.5, wire diameter 13μm, Taishan Fiberglass;

[0081] Continuous roving: EDR14-2000-988A, wire diameter 14μm, Jushi Group;

[0082] Lubricant: A mixture of polar wax and polyethylene wax with a mass ratio of 2:1; among them, polyethylene wax (PE wax) is BN500, Qingdao Bangni; polar wax is RBW102, Clariant;

[0083] Antioxidant: A compound antioxidant of hindered phenols and phosphites, B215, Lion Chemical.

[0084] The following will be described in detail in combination with specific examples and comparative examples.

[0085] Examples 1 to 4

[0086] Examples 1 to 4 provide a polyolefin material. The formula is shown in Table 1. The preparation method includes the following steps:

[0087] Mix polypropylene resin, polyethylene resin, toughening agent, filler, lubricant, and antioxidant evenly in proportion, and add them into a twin-screw extruder from the main feed port. Add glass fiber from the side feed port or exhaust port. Among them, when the glass fiber is chopped glass fiber, it is added from the side feed port, and when it is continuous roving, it is added from the fiber adding port; then melt in the twin-screw extruder, and perform extrusion and pelletizing to obtain the polyolefin material; the extrusion temperatures of the first to the eleventh zones of the twin-screw extruder are 200°C, 220°C, 220°C, 220°C, 225°C, 225°C, 225°C, 230°C, 230°C, 220°C, and 210°C respectively.

[0088] Table 1 Formulation table of the polyolefin material in Examples 1 to 4 (parts by mass)

[0089] Example 1 Example 2 Example 3 Example 4 Polypropylene Resin 1 (PP Z30S) 58 56 Polypropylene Resin 2 (PP PPH-G70T) 55 56 Polyethylene Resin 1 (LDPE MG70) 10 15 13 10 Toughening Agent 1 (POE 9061) 6 8 Toughening Agent 2 (POE 8150) 4 5 Barium Sulfate 10 15 12.5 10 Chopped Glass Fiber 15 10 Continuous Rovings 12.5 15 Lubricant 0.7 0.7 0.7 0.7 Antioxidant 0.3 0.3 0.3 0.3

[0090] Comparative Example 1

[0091] This comparative example prepared a polyolefin material, which is different from Example 1 in that: polypropylene resin 1 (PP Z30S) was replaced with polypropylene resin 3 (PP EP548R) in equal amount; the specific formulation dosage is shown in Table 2, and the preparation method is the same as that of Example 1.

[0092] Comparative Example 2

[0093] This comparative example prepared a polyolefin material, which is different from Example 2 in that: polyethylene resin 1 (LDPEMG70) was replaced with polyethylene resin 2 (LDPE 2420H) in equal amount; the specific formulation dosage is shown in Table 2, and the preparation method is the same as that of Example 2.

[0094] Comparative Example 3

[0095] In this comparative example, a polyolefin material was prepared. The difference from Example 2 was that polyethylene resin 1 (LDPEMG70) was replaced with polyethylene resin 3 (LLDPE M2320) in equal amounts; for the specific formulation dosages, see Table 2, and the preparation method was the same as that in Example 2.

[0096] Comparative Example 4

[0097] In this comparative example, a polyolefin material was prepared. The difference from Example 3 was that polyethylene resin 1 (LDPEMG70) was replaced with polyethylene resin 4 (HDPE 5502) in equal amounts; for the specific formulation dosages, see Table 2, and the preparation method was the same as that in Example 3.

[0098] Comparative Example 5

[0099] In this comparative example, a polyolefin material was prepared. The difference from Example 4 was that toughening agent 1 (POE 9061) was replaced with toughening agent 3 (POE 6202) in equal amounts; for the specific formulation dosages, see Table 2, and the preparation method was the same as that in Example 4.

[0100] Comparative Example 6

[0101] In this comparative example, a polyolefin material was prepared. The difference from Example 2 was that barium sulfate was replaced with talc; for the specific formulation dosages, see Table 2, and the preparation method was the same as that in Example 2.

[0102] Comparative Example 7

[0103] In this comparative example, a polyolefin material was prepared. The difference from Example 2 was that barium sulfate was replaced with calcium carbonate; for the specific formulation dosages, see Table 2, and the preparation method was the same as that in Example 2.

[0104] Comparative Example 8

[0105] In this comparative example, a polyolefin material was prepared. The difference from Example 3 was that a compatibilizer was added and the addition amount of polypropylene resin was reduced accordingly; for the specific formulation dosages, see Table 2, and the preparation method was the same as that in Example 3.

[0106] Comparative Example 9

[0107] In this comparative example, a polyolefin material was prepared. The difference from Example 3 was that no polyethylene resin was added and the addition amount of polypropylene resin was increased accordingly; for the specific formulation dosages, see Table 2, and the preparation method was the same as that in Example 3.

[0108] Comparative Example 10

[0109] This comparative example prepared a polyolefin material, which was different from Example 1 in that: no toughening agent was added, and the addition amount of polypropylene resin was correspondingly increased; for the specific formulation dosage, see Table 2, and the preparation method was the same as that of Example 1.

[0110] Comparative Example 11

[0111] This comparative example prepared a polyolefin material, which was different from Example 1 in that: no barium sulfate was added, and the addition amount of chopped glass fiber was correspondingly increased; for the specific formulation dosage, see Table 2, and the preparation method was the same as that of Example 1.

[0112] Comparative Example 12

[0113] This comparative example prepared a polyolefin material, which was different from Example 1 in that: no chopped glass fiber was added, and the addition amount of barium sulfate was correspondingly increased; for the specific formulation dosage, see Table 2, and the preparation method was the same as that of Example 1.

[0114] Table 2 Formulation table of polyolefin materials for Comparative Examples 1 - 12 (parts by mass)

[0115]

[0116]

[0117] Result detection

[0118] The polyolefin materials obtained in the above examples and comparative examples were injection molded using a horizontal injection molding machine to obtain specimens; the conditions for injection molding were: the four-stage injection molding temperatures from the feeding port to the nozzle were 195°C, 200°C, 200°C, and 195°C in sequence; the injection pressure was 55 MPa, the holding pressure time was 8 s, the cooling time was 8 s, and the materials were dried at 105°C for 2 h before injection molding. The specifications of the specimens were determined according to the required specifications for testing, and the obtained specimens were used for performance testing. The testing methods were as follows:

[0119] Melt index (MI): Tested according to ASTM D1238 - 2010 standard, temperature 230°C, load 2.16 kg;

[0120] Tensile strength: Tested according to ASTM D638 - 2010 standard, the thickness of the specimen is 3.0 mm;

[0121] Flexural property, tested according to ASTM D790 - 2017 standard, the thickness of the specimen is 3.0 mm;

[0122] Izod notched impact strength: Tested according to ASTM D256 - 2010 standard, the thickness of the specimen is 3.0 mm;

[0123] Heat distortion temperature: Tested according to ASTM D648 - 2010 standard, the thickness of the specimen is 6.0 mm;

[0124] Flat warpage height: Fix one end of the gate of the injection-molded long optical plate specimen (150mm * 450mm * 1.5mm), and measure the warpage height at the end of the plate.

[0125] Glossiness: Test according to ISO 2813 standard, and record the glossiness measured under the condition of 60°.

[0126] Shrinkage rate: Injection-mold a square plate (150mm * 150mm * 3.0mm), measure the width of the square plate after cooling, and calculate its shrinkage rate according to the width difference.

[0127] See Tables 3 - 11 for the test results.

[0128] Table 3 Performance test results of polyolefin materials in Examples 1 - 4

[0129]

[0130]

[0131] As can be seen from Table 3, the injection-molded parts of the polyolefin materials obtained in Examples 1 - 4 of the present invention have a tensile strength of not less than 29 MPa, a flexural modulus of not less than 2690 MPa, a notched Izod impact strength of not less than 110 J / m, and the glossiness of the glossy surface at a 60° angle is all above 60%. The shrinkage rate does not exceed 0.7%, and the flat warpage height does not exceed 1.3 mm. At the same time, it has high heat resistance, and the heat distortion temperature is not less than 135 °C. It can be seen that the polyolefin material of the present invention has excellent mechanical strength, high glossiness, low shrinkage rate, and obvious warpage deformation. Its mechanical properties are comparable to those of ABS materials, and it can replace traditional ABS materials to prepare the outer shells of household appliances. At the same time, it has a higher heat distortion temperature than ABS materials and can adapt to a working environment with a higher temperature. At the same time, the polyolefin materials obtained in Examples 1 - 4 of the present invention also have a moderate melt index, which is beneficial to production and processing and ensures the material strength.

[0132] Table 4 Performance test results of polyolefin materials in Example 1 and Comparative Example 1

[0133] Test Items Example 1 Comparative Example 1 MI (g / 10min) 12 12 Tensile Strength (MPa) 30 25 Flexural Modulus (MPa) 2750 2320 Impact Strength (J / m) 125 155 Flat Warpage Height (mm) 1.2 1.4 Gloss (60°) 62 52 Shrinkage Rate (%) 0.5 0.6

[0134] As can be seen from Table 4, compared with Example 1, in Comparative Example 1, the polypropylene resin was replaced, and a polypropylene resin with a lower flexural modulus was used. The obtained polyolefin material not only has a lower flexural modulus but also a lower glossiness.

[0135] Table 5 Performance test results of polyolefin materials in Example 2 and Comparative Examples 2 - 3

[0136]

[0137]

[0138] As can be seen from Table 5, compared with Example 2, in Comparative Examples 2 and 3, the polyethylene resin was replaced, and LDPE or LLDPE with a lower melt index was used, resulting in a significant decrease in the gloss of the polyolefin material, which was not more than 55.

[0139] Table 6 Performance test results of the polyolefin materials of Example 3 and Comparative Example 4

[0140] Test Items Example 3 Comparative Example 4 MI (g / 10min) 11 8 Tensile Strength (MPa) 29 31 Flexural Modulus (MPa) 2690 2970 Impact Strength (J / m) 140 145 Flat Warpage Height (mm) 1.0 4.5 Gloss (60°) 63 50 Shrinkage Rate (%) 0.6 0.5

[0141] As can be seen from Table 6, compared with Example 3, in Comparative Example 4, HDPE with a melt index of only 0.3 g / 10 min was used. Due to the significant decrease in the fluidity of the polyethylene resin, the fluidity of the polyolefin material also decreased significantly. During the processing, the fiber glass dispersion in the system was poor, resulting in more serious warping deformation of the injection molded parts of the polyolefin material, and the gloss also decreased significantly.

[0142] Table 7 Performance test results of the polyolefin materials of Example 4 and Comparative Example 5

[0143] Test Items Example 4 Comparative Example 5 MI (g / 10min) 22 24 Tensile Strength (MPa) 34 33 Flexural Modulus (MPa) 3110 3020 Impact Strength (J / m) 115 85 Flat Warpage Height (mm) 1.3 1.1 Gloss (60°) 60 60 Shrinkage Rate (%) 0.5 0.6

[0144] As can be seen from Table 7, compared with Example 4, in Example 5, the toughening agent with a higher melt index was replaced, and the toughening effect was poor, and it was impossible to take into account high impact strength.

[0145] Table 8 Performance test results of the polyolefin materials of Example 2 and Comparative Examples 6 - 7

[0146]

[0147]

[0148] As can be seen from Table 8, compared with Example 2, in Comparative Examples 6 and 7, the filler barium sulfate was replaced with talc or calcium carbonate. In Comparative Example 6, both the impact strength and the gloss decreased significantly, and the gloss in Comparative Example 7 also decreased significantly.

[0149] Table 9 Performance test results of the polyolefin materials of Example 3 and Comparative Examples 8 - 9

[0150] Test Items Example 3 Comparative Example 8 Comparative Example 9 MI (g / 10min) 11 9 9 Tensile Strength (MPa) 29 50 32 Flexural Modulus (MPa) 2690 3380 2890 Impact Strength (J / m) 140 165 55 Flat Warpage Height (mm) 1.0 3.5 2.5 Gloss (60°) 63 65 62 Shrinkage Rate (%) 0.6 0.5 0.8

[0151] As can be seen from Table 9, compared with Example 3, a compatibilizer was added in Comparative Example 8. Although the mechanical properties of the polyolefin material were improved, the warpage deformation was more serious, and the warpage height of the flat plate reached 3.5 times that of Example 3; in Comparative Example 9, no polyethylene resin was added, the obtained polyolefin material had a higher shrinkage rate, more obvious warpage deformation, and at the same time, the impact strength decreased.

[0152] Table 10 Performance test results of the polyolefin materials of Example 1 and Comparative Example 10

[0153] Test Items Example 1 Comparative Example 10 MI (g / 10min) 12 25 Tensile Strength (MPa) 30 37 Flexural Modulus (MPa) 2750 3480 Impact Strength (J / m) 125 65 Flat Warpage Height (mm) 1.2 1.8 Gloss (60°) 62 63 Shrinkage Rate (%) 0.5 0.7

[0154] As can be seen from Table 10, compared with Example 1, no toughening agent was added in Comparative Example 10, the impact strength decreased significantly, it was difficult to be applied to household electrical appliances products, and its warpage deformation was also more obvious.

[0155] Table 11 Performance test results of the polyolefin materials of Example 1 and Comparative Examples 11 - 12

[0156] Test Items Example 1 Comparative Example 11 Comparative Example 12 MI (g / 10min) 12 10 15 Tensile Strength (MPa) 30 33 22 Flexural Modulus (MPa) 2750 3260 1450 Impact Strength (J / m) 125 130 195 Flat Warpage Height (mm) 1.2 1.8 0.2 Gloss (60°) 62 52 82 Shrinkage Rate (%) 0.5 0.4 1.3

[0157] As can be seen from Table 11, compared with Example 1, no filler was added in Comparative Example 11, and the amount of glass fiber was increased. The warpage deformation of the polyolefin material was more obvious, and the gloss decreased significantly; in Comparative Example 12, no glass fiber was added, and the amount of filler was increased. Although the gloss of the obtained polypropylene resin was improved to some extent, the flexural modulus decreased severely, and the shrinkage rate also increased significantly.

[0158] In summary, through the compounding of specific components, the polyolefin material of the present invention ensures the mechanical strength of the polyolefin material, while reducing the shrinkage rate, improving the gloss, and reducing the warpage deformation of the injection molded parts of the polyolefin material, solving the problems of warpage deformation, low gloss, and low toughness existing in traditional glass fiber reinforced polypropylene materials, and is applicable to the field of household electrical appliances products, especially applicable to the preparation of the outer shells of household electrical appliances products.

[0159] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A polyolefin material, characterized in that, By mass parts, it includes the following components: 45 - 70 parts of polypropylene resin, 8 - 25 parts of polyethylene resin, 3 - 10 parts of toughening agent, 8 - 18 parts of glass fiber, 8 - 18 parts of filler, 0 - 1 part of lubricant, 0 - 0.5 part of antioxidant; The polyolefin material does not contain a compatibilizer; The polypropylene resin is a homopolypropylene resin; the polyethylene resin is a low - density polyethylene resin.

2. The polyolefin material according to claim 1, characterized in that, The melt index of the polypropylene resin at 230°C under a load of 2.16 kg is 25 - 100 g / 10 min; And / or, the flexural modulus of the polypropylene resin is 1300 - 2500 MPa.

3. The polyolefin material according to claim 1, characterized in that, The melt index of the polyethylene resin at 190°C under a load of 2.16 kg is 50 - 150 g / 10 min; And / or, the Izod notched impact strength of the polyethylene resin is 300 - 900 J / m.

4. The polyolefin material according to claim 1, characterized in that, The toughening agent includes at least one of ethylene - butene copolymer and ethylene - octene copolymer; And / or, the melt index of the toughening agent at 190°C under a load of 2.16 kg is 0.1 - 2 g / 10 min.

5. The polyolefin material according to claim 1, characterized in that, The glass fiber includes at least one of chopped glass fiber and continuous roving; And / or, the wire diameter of the glass fiber is 10 - 30 μm.

6. The polyolefin material according to claim 1, characterized in that, The filler is barium sulfate; And / or, the whiteness of the filler ≥ 98%; And / or, the average particle size of the filler is 0.1 - 10 μm.

7. The polyolefin material according to claim 1, characterized in that, The lubricant includes at least one of polyethylene wax and polar wax; And / or, the antioxidant includes at least one of hindered phenol antioxidants and phosphite antioxidants.

8. A method for preparing the polyolefin material according to any one of claims 1 to 7, characterized in that, It includes the following steps: Mix, melt, and extrude each component to obtain the polyolefin material described above.

9. The preparation method according to claim 8, characterized in that, The temperature of the extrusion is 200 - 250°C.

10. Use of the polyolefin material according to any one of claims 1 - 7 in the preparation of household electrical appliances.

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