Impact-resistant high-density polyethylene composite material and preparation method thereof

Abstract

The invention relates to the field of polyethylene composite materials, and discloses an impact-resistant high-density polyethylene composite material and a preparation method thereof.The impact-resistant high-density polyethylene composite material is prepared from, by weight, 60-70 parts of matrix resin, 5-11 parts of flexibilizer, 4-9 parts of inorganic filler, 1-3 parts of compatilizer, 0.5-1.5 parts of antioxidant and 2-4 parts of ultraviolet stabilizer, the matrix resin is high-density polyethylene with the molecular weight of 90,000-120,000, and the flexibilizer is a compatilizer. The flexibilizer is chlorinated polyethylene, the chlorine content is 25 + / -1 wt%, the inorganic filler is modified talcum powder, the D50 particle size is smaller than or equal to 3 microns, and the length-diameter ratio is larger than or equal to 10. The surface of the talcum powder is modified by gamma-aminopropyltriethoxysilane, and the length-diameter ratio of the particle size is controlled, so that the chemical bonding effect of the filler and a high-density polyethylene matrix is enhanced, the high-efficiency transmission and uniform dispersion of stress are facilitated, and the local stress concentration phenomenon under the impact load is effectively inhibited.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polyethylene composite materials, in particular to an impact-resistant high-density polyethylene composite material and a preparation method thereof. BACKGROUND

[0002] In the fields of outdoor engineering, packaging and transportation, fluid delivery and mechanical component manufacturing, there are high requirements for the impact resistance, structural strength and performance stability of the materials used, and the materials need to be able to withstand impact load and tensile stress stably, and maintain good mechanical properties in complex environments such as high temperature, oxidation and ultraviolet radiation. The impact-resistant high-density polyethylene composite material can meet the application requirements in these scenarios due to its balanced mechanical properties and suitable aging resistance.

[0003] To meet the requirements of these fields for material properties, inorganic fillers and other methods are often used to improve the mechanical properties of materials, to enhance the structural strength and impact resistance of materials, and to make the materials more suitable for the stress environment and use conditions in actual applications.

[0004] However, in the prior art, the interfacial bonding force between the inorganic filler and the matrix resin is weak, and the dispersion in the matrix is not uniform enough, and it is difficult to form effective directional arrangement, which makes the material prone to local stress concentration when subjected to impact load, thereby affecting the mechanical properties and aging resistance of the material. SUMMARY

[0005] To overcome the deficiencies of the prior art, the present application provides an impact-resistant high-density polyethylene composite material and a preparation method thereof, which solves the problem of weak interfacial bonding force between the inorganic filler and the matrix resin in the prior art, and the problem of uneven dispersion in the matrix, which makes it difficult to form effective directional arrangement.

[0006] To achieve the above purpose, the present application realizes the following technical scheme: an impact-resistant high-density polyethylene composite material, comprising the following raw materials by weight:

[0007] 60-70 parts of matrix resin, 5-11 parts of toughening agent, 4-9 parts of inorganic filler, 1-3 parts of compatibilizer, 0.5-1.5 parts of antioxidant, and 2-4 parts of ultraviolet stabilizer.

[0008] By adopting the above technical scheme: since 60-70 parts of the base resin is adopted as the main framework, a stable structural basis can be provided for the composite material, 5-11 parts of the toughening agent is moderately matched with the base resin to improve the material toughness while ensuring the basic strength, 4-9 parts of the inorganic filler can enhance the material rigidity and avoid the toughness decline caused by excessive amount, 1-3 parts of the compatilizer can promote the interface combination between the components to ensure uniform dispersion, 0.5-1.5 parts of the antioxidant and 2-4 parts of the ultraviolet stabilizer synergistically resist thermal-oxidative aging and ultraviolet aging, and the component amount is matched to form a balanced system, therefore, the composite material with balanced mechanical properties, good processing stability and adaptive aging resistance performance is obtained.

[0009] Preferably, the base resin is high-density polyethylene with a molecular weight of 90,000-120,000.

[0010] By adopting the above technical scheme: by adopting the above technical scheme, since the high-density polyethylene with a molecular weight of 90,000-120,000 is adopted as the base resin, the molecular chain length is appropriate and the entanglement degree is moderate, a stable skeleton support can be provided for the composite material, a good interface combination is formed with the toughening agent and inorganic filler components, and the melt flowability during the processing process and the structural stability after cooling are considered at the same time, therefore, the composite material with excellent mechanical strength, good impact resistance and strong processing adaptability is obtained.

[0011] Preferably, the toughening agent is chlorinated polyethylene with a chlorine content of 25±1wt%.

[0012] By adopting the above technical scheme: since the chlorinated polyethylene with a chlorine content of 25±1wt% is adopted as the toughening agent, the molecular chain polarity is adapted to the characteristics of the high-density polyethylene matrix, the interface compatibility is effectively enhanced, and a uniform and flexible network structure is formed through intermolecular entanglement to significantly optimize the stress transfer efficiency, therefore, the impact toughness is significantly improved while the material rigidity is ensured, and the performance stability in long-term thermal-oxidative aging environment is improved.

[0013] Preferably, the inorganic filler is modified talc powder with a D50 particle size ≤3μm and an aspect ratio ≥10, and the modifier is γ-aminopropyl triethoxysilane.

[0014] By adopting the above technical scheme: since the talc powder is surface modified by γ-aminopropyl triethoxysilane, and the D50 particle size is strictly controlled to be ≤3μm and the aspect ratio is ≥10, the interface bonding strength between the talc powder and the high-density polyethylene matrix is significantly improved, and uniform dispersion and directional arrangement of the inorganic filler in the resin are realized, the stress concentration phenomenon is effectively inhibited, and the load transfer efficiency is enhanced, therefore, the impact toughness and tensile strength of the composite material are synergistically enhanced, and the interface structure is stable in long-term thermal-oxidative aging environment.

[0015] Preferably, the compatilizer is maleic anhydride grafted polyolefin elastomer.

[0016] By adopting the above technical scheme: since maleic anhydride grafted polyolefin elastomer is used as the compatilizer, the maleic anhydride groups in the molecular chain can form chemical bonding with the surface of the inorganic filler, and the polyolefin segment can realize molecular-level entanglement with the high-density polyethylene matrix, effectively bridging the interface between the organic and inorganic phases, reducing the interface energy and strengthening the stress transmission, so that the impact toughness and tensile strength of the composite material are significantly improved, and the long-term dispersion stability of the filler in the matrix is ensured, and the interface peeling phenomenon in the thermal oxidation process is inhibited.

[0017] Preferably, the antioxidant is tertiary butyl hydroquinone with a hydroxyl value of 210±5 mgKOH / g.

[0018] By adopting the above technical scheme: since tertiary butyl hydroquinone with a hydroxyl value of 210±5 mgKOH / g is used as the antioxidant, the high-activity phenolic hydroxyl group can efficiently capture free radicals generated in the high-temperature processing and use process, inhibit the oxidative degradation reaction of the polymer molecular chain, and at the same time, synergistically passivate metal ion catalytic activity, so that the thermal oxidation process of the composite material is significantly delayed, the molecular chain structure integrity is effectively maintained, and the impact toughness stability and service life of the material in a long-term high-temperature or oxidation environment are ensured.

[0019] Preferably, the ultraviolet stabilizer is titanium dioxide.

[0020] By adopting the above technical scheme: since titanium dioxide is used as the ultraviolet stabilizer, its wide-band ultraviolet shielding characteristics can efficiently reflect and scatter incident ultraviolet radiation, block the photoexcitation degradation path of the high molecular chain, and at the same time, synergistically inhibit the generation and diffusion of free radicals in the photooxidation reaction, so that the molecular chain rupture and surface powdering phenomenon of the composite material in an outdoor exposure environment are significantly delayed, the color stability and mechanical properties of the material are effectively maintained, and the outdoor service life is prolonged.

[0021] Preferably, the application further provides a preparation method of the impact-resistant high-density polyethylene composite material, comprising the following steps:

[0022] S1, drying raw materials, drying high-density polyethylene, chlorinated polyethylene, maleic anhydride grafted polyolefin elastomer, tertiary butyl hydroquinone and titanium dioxide at 80°C for 2-4 hours to obtain dry raw material components;

[0023] S2, dry mixing and pre-dispersing, mixing the modified talc powder with the dry raw material components and controlling the temperature, stirring at a speed of 300-500 rpm for 5-10 minutes to obtain a premix;

[0024] S3, melt blending extrusion, the premix is added into the extruder and the temperature is controlled, the screw rotation speed is 300-400 rpm, the melt material is extruded to generate a melt composite material;

[0025] S4, granulation and drying, the melt composite material is cut into particles by water cooling, and the particles are dried at 80 DEG C for 1-2 hours to obtain composite material particles.

[0026] Preferably, in S2, the temperature is controlled at 20-30 DEG C.

[0027] Preferably, in S3, the temperature is controlled at 180-200 DEG C.

[0028] By adopting the above technical scheme: in the S1 drying process, the easily hydrolyzed component is dehydrated at 80 DEG C for 2-4 hours, which effectively eliminates the interface defects caused by the surface moisture of the raw material. In the S2 dry mixing process, the temperature is strictly controlled at 20-30 DEG C and the high-speed stirring at 300-500 rpm is adopted, which not only avoids the adhesion of the toughening agent but also realizes the uniform pre-dispersion of the modified talc powder in the resin. In the S3 extrusion process, the synergistic effect of the melt temperature of 180-200 DEG C and the screw rotation speed of 300-400 rpm not only inhibits thermal degradation but also strengthens the shear dispersion force, which promotes the directional arrangement of the inorganic filler. Finally, in the S4 granulation process, the water cooling and rapid solidification are combined with the low-temperature drying at 80 DEG C, which simultaneously realizes the regularization of the particle morphology and the release of internal stress, so that the composite material particles with high dispersity, low interface defects and complete molecular chain structure are obtained, which lays a foundation for the comprehensive mechanical properties and long-term stability of the material.

[0029] The application provides an impact-resistant high-density polyethylene composite material and a preparation method thereof.

[0030] 1. The application controls the surface modification of talc powder by γ-aminopropyl triethoxysilane and the aspect ratio of particle size, enhances the chemical bonding effect of the filler and the high-density polyethylene matrix, is beneficial to efficient stress transmission and uniform dispersion, and effectively inhibits the local stress concentration phenomenon under impact load.

[0031] 2. The application realizes the synergistic effect of the toughening network of chlorinated polyethylene with precise chlorine content and the high-activity hydroxyl antioxidant, effectively blocks the thermal oxidative degradation chain reaction while ensuring impact toughness, combines the ultraviolet shielding function of titanium dioxide, and significantly delays the performance degradation of the composite material in high-temperature, oxidation and outdoor environments.

[0032] 3. The application realizes the high-efficiency free radical capture ability of high-hydroxyl-value tertiary butylhydroquinone, blocks the molecular chain degradation path in high-temperature and oxidation environments, and cooperates with the passivation of metal ion catalytic activity to delay the performance degradation of the composite material. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1Flow chart of the preparation method of the impact-resistant high-density polyethylene composite material of the present application. DETAILED DESCRIPTION

[0034] The technical solutions of the present application will be described clearly and completely below in combination with the drawings of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0035] The present application will be further described in detail below in combination with the examples and comparative examples.

[0036] Specific types of raw materials:

[0037] The high-density polyethylene is selected from Daqing Petrochemical, and the brand is HDPE2200J;

[0038] The chlorinated polyethylene is selected from Yaxing Chemical, and the brand is

[0039] The gamma-aminopropyl triethoxysilane is selected from Anhui Boit, and the brand is FD-550;

[0040] The maleic anhydride grafted polyolefin elastomer is selected from Dow Chemical, and the brand is Fusabond TM N216;

[0041] The tert-butyl hydroquinone is selected from Balingwei Technology, and the hydroxyl value is 210±5 mgKOH / g;

[0042] The titanium dioxide is selected from DuPont Titanium White, and the brand is Ti-Pure TM R-900.

[0043] Preparation example of modified talc powder:

[0044] Talc and gamma-aminopropyl triethoxysilane are used as raw materials. The talc is dried at 80-100°C for 2-4 hours to remove surface moisture. Then the dried talc is mixed with gamma-aminopropyl triethoxysilane. The silane addition amount is 1.0-1.5% of the weight of the talc. The temperature is controlled at 80-100°C, and the stirring time is 10-15 minutes to make the silane fully react with the surface hydroxyl groups of the talc. Finally, the modified talc powder is obtained after drying treatment.

[0045] Example 1

[0046] High-density polyethylene 65 parts, chlorinated polyethylene 8 parts, modified talc powder 6 parts, maleic anhydride grafted polyolefin elastomer 2 parts, tert-butyl hydroquinone 1 part, titanium dioxide 3 parts.

[0047] S1, raw material drying: dry high density polyethylene, chlorinated polyethylene, maleic anhydride grafted polyolefin elastomer, tert-butyl hydroquinone and titanium dioxide at 80°C for 3 hours to obtain dry raw material components; S2, dry mixing and pre-dispersing: mix modified talcum powder with dry raw material components, control temperature at 25°C, stirring speed at 400 rpm, and continue for 8 minutes to obtain premix;

[0048] S3, melt blending and extruding: add the premix into the extruder, control temperature at 190°C, screw rotation speed at 350 rpm, extrude the melt material to generate a melt composite material;

[0049] S4, granulation and drying: water-cool the melt composite material to form particles, and dry the particles at 80°C for 1.5 hours to obtain composite material particles.

[0050] Example 2

[0051] High density polyethylene 60 parts, chlorinated polyethylene 11 parts, modified talcum powder 9 parts, maleic anhydride grafted polyolefin elastomer 3 parts, tert-butyl hydroquinone 1.5 parts, titanium dioxide 4 parts.

[0052] S1, raw material drying: dry high density polyethylene, chlorinated polyethylene, maleic anhydride grafted polyolefin elastomer, tert-butyl hydroquinone and titanium dioxide at 80°C for 4 hours to obtain dry raw material components;

[0053] S2, dry mixing and pre-dispersing: mix modified talcum powder with dry raw material components, control temperature at 30°C, stirring speed at 500 rpm, and continue for 10 minutes to obtain premix;

[0054] S3, melt blending and extruding: add the premix into the extruder, control temperature at 200°C, screw rotation speed at 400 rpm, extrude the melt material to generate a melt composite material;

[0055] S4, granulation and drying: water-cool the melt composite material to form particles, and dry the particles at 80°C for 2 hours to obtain composite material particles.

[0056] Example 3

[0057] High density polyethylene 70 parts, chlorinated polyethylene 5 parts, modified talcum powder 4 parts, maleic anhydride grafted polyolefin elastomer 1 part, tert-butyl hydroquinone 0.5 part, titanium dioxide 2 parts.

[0058] S1, raw material drying: dry high density polyethylene, chlorinated polyethylene, maleic anhydride grafted polyolefin elastomer, tert-butyl hydroquinone and titanium dioxide at 80°C for 2 hours to obtain dry raw material components;

[0059] S2, dry mixing pre-dispersion: mix modified talc powder with dry raw material components, control temperature 20℃, stirring speed 300rpm, last for 5 minutes, obtain premix;

[0060] S3, melt blending extrusion: put premix into extruder, control temperature 180℃, screw rotation speed 300rpm, extrude melt material, generate melt composite material;

[0061] S4, granulation and drying: melt composite material is water-cooled and granulated, granules are dried at 80℃ for 1 hour, obtain composite material granules.

[0062] Comparative Example 1

[0063] Different from Example 1: inorganic filler is unmodified talc powder without γ-aminopropyl triethoxysilane treatment, the rest of raw materials and preparation method are the same as Example 1.

[0064] Comparative Example 2

[0065] Different from Example 1: inorganic filler is modified talc powder D50 particle size 4μm aspect ratio 8, the rest of raw materials and preparation method are the same as Example 1.

[0066] Comparative Example 3

[0067] Different from Example 1: toughening agent is chlorinated polyethylene with chlorine content 20wt%, the rest of raw materials and preparation method are the same as Example 1.

[0068] Comparative Example 4

[0069] Different from Example 1: toughening agent is ethylene-vinyl acetate copolymer, the rest of raw materials and preparation method are the same as Example 1.

[0070] Comparative Example 5

[0071] Different from Example 1: antioxidant is tertiary butyl hydroquinone with hydroxyl value 190mgKOH / g, the rest of raw materials and preparation method are the same as Example 1.

[0072] Comparative Example 6

[0073] Different from Example 1: antioxidant is 2,6-di-tert-butyl-p-cresol, the rest of raw materials and preparation method are the same as Example 1.

[0074] Performance test test

[0075] Test sample: composite material prepared in the above examples and comparative examples.

[0076] Test standards and methods:

[0077] Charpy impact strength: tested according to GB / T1043.1-2008 "Determination of Charpy Impact Properties of Plastics - Part 1: Non-Instrumented Impact Test", using A-type notched specimens, at a test temperature of 23°C, with 5 specimens per group and the average value taken.

[0078] Tensile strength: tested according to GB / T1040.2-2006 "Determination of Tensile Properties of Plastics - Part 2: Test Conditions for Moulded and Extruded Plastics", using 1A-type specimens, at a tensile rate of 50 mm / min, at a test temperature of 23°C, with 5 specimens per group and the average value taken.

[0079] Impact strength retention rate after thermal oxidative aging: according to GB / T7141-2008 "Plastics - Methods of Thermal Oxidative Aging", the specimens were placed in a 100°C hot air aging oven for 168 h, and after cooling to 23°C, the performance after aging was measured according to the above-mentioned Charpy impact strength test method, and the percentage of the impact strength before aging was calculated as the retention rate.

[0080] Table 1: Effect table of examples, comparative examples.

[0081]

[0082] Comparison item explanation:

[0083] Charpy impact strength (kJ / m 2 ): measures the ability of a material to resist fracture under impact loading, the higher the value, the stronger the impact toughness of the material, and the less likely it is to break brittlely when subjected to impact, such as collision, falling, etc., suitable for scenarios requiring impact resistance.

[0084] Tensile strength (MPa): represents the maximum ability of a material to resist damage under tensile loading, the higher the value, the stronger the ability of the material to withstand tensile stress, and the less likely it is to deform or break due to tension during the stress process, suitable for structural parts that need to bear tension.

[0085] Impact strength retention rate after thermal oxidative aging (%): the percentage of the remaining impact strength to the initial strength of the material after thermal oxidative aging test, the higher the value, the better the thermal oxidative aging resistance of the material, the slower the performance degradation in long-term high temperature or oxidative environment, and the longer the service life.

[0086] The main differences in test parameters between the examples and comparative examples are reflected in the characteristics of the raw materials and the parameters of the key components, and the specific effects are as follows:

[0087] Inorganic filler, the embodiment uses talc powder modified by γ-aminopropyl triethoxysilane, and controls D50 particle size ≤3 μm, aspect ratio ≥10, while comparative example 1 uses unmodified talc powder, and the talc powder of comparative example 2 has a particle size of 4 μm and an aspect ratio of only 8. Modification and parameter adaptation can enhance the interfacial bonding force between talc powder and the polymer matrix, and unmodified or parameter deviation can lead to uneven dispersion of fillers and weaken the improvement of material mechanical properties.

[0088] The parameters of the toughening agent differ significantly, the embodiment selects chlorinated polyethylene with a chlorine content of 25±1wt%, the chlorine content of the chlorinated polyethylene of comparative example 3 is reduced to 20wt%, and comparative example 4 uses ethylene and vinyl acetate copolymer instead. Suitable chlorine content can optimize the compatibility of the toughening agent and the matrix, and low chlorine content or species replacement will reduce the entanglement between molecular chains, resulting in a decrease in impact resistance of the material.

[0089] The parameters and types of antioxidants affect the aging resistance, the embodiment uses tertiary butyl hydroquinone with a hydroxyl value of 210±5mgKOH / g, the hydroxyl value of the tertiary butyl hydroquinone of comparative example 5 is only 190mgKOH / g, and comparative example 6 is replaced by 2,6-di-tert-butyl-p-cresol. Hydroxyl value is too weak to capture free radicals, resulting in a significant decrease in impact strength retention rate after thermal oxidative aging.

[0090] Although embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made thereto without departing from the principles and spirit of the application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. Impact-resistant high-density polyethylene composite material, characterized in that: The invention comprises the following raw materials in parts by weight: 60-70 parts of base resin, 5-11 parts of toughening agent, 4-9 parts of inorganic filler, 1-3 parts of compatibilizer, 0.5-1.5 parts of antioxidant, and 2-4 parts of UV stabilizer.

2. The impact-resistant high-density polyethylene composite material according to claim 1, characterized in that: The matrix resin is high-density polyethylene with a molecular weight of 90,000-120,000.

3. The impact-resistant high-density polyethylene composite material according to claim 1, characterized in that: The toughening agent is chlorinated polyethylene with a chlorine content of 25±1 wt%.

4. The impact-resistant high-density polyethylene composite material according to claim 1, characterized in that The inorganic filler is modified talc powder, with a D50 particle size of ≤3 μm and an aspect ratio of ≥10, and the modifier is γ-aminopropyltriethoxysilane.

5. The impact-resistant high-density polyethylene composite material according to claim 1, characterized in that: The compatibilizer is maleic anhydride grafted polyolefin elastomer.

6. The impact-resistant high-density polyethylene composite material according to claim 1, characterized in that: The antioxidant is tert-butylhydroquinone, with a hydroxyl value of 210±5 mgKOH / g.

7. The impact-resistant high-density polyethylene composite material according to claim 1, characterized in that: The ultraviolet stabilizer is titanium dioxide.

8. A method for preparing an impact-resistant high-density polyethylene composite material, for use in the impact-resistant high-density polyethylene composite material according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1. Drying the raw materials: drying high-density polyethylene, chlorinated polyethylene, maleic anhydride grafted polyolefin elastomer, tert-butylhydroquinone and titanium dioxide at 80° C. for 2-4 hours to obtain a dry raw material component; S2, dry mixing pre-dispersion, mixing the modified talc powder with the dry raw material components and controlling the temperature, stirring at a speed of 300-500 rpm for 5-10 minutes to obtain a premix; S3, melt blending extrusion, adding the premix to the extruder and controlling the temperature, the screw speed is 300-400 rpm, and the molten material is extruded to form a molten composite material; S4, granulation and drying: the molten composite material is pelletized by water cooling, and the pellets are dried at 80° C. for 1-2 hours to obtain composite material particles.

9. The method for preparing the impact-resistant high-density polyethylene composite material according to claim 8, wherein: In S2, the temperature is controlled at 20-30°C.

10. The method for preparing the impact-resistant high-density polyethylene composite material according to claim 8, characterized in that: In S3, the temperature is controlled at 180-200°C.

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