High-strength anti-aging insect-resistant polyethylene composite material and preparation method thereof

Abstract

The invention discloses a high-strength anti-aging insect-resistant polyethylene composite material and a preparation method thereof, and belongs to the technical field of plastic processing. The high-strength anti-aging insect-resistant polyethylene composite material is prepared by the following steps: preparing modified nano titanium dioxide from a KH540 silane coupling agent and rutile type nano titanium dioxide; high-density polyethylene and maleic anhydride are used as raw materials to prepare polyethylene grafted maleic anhydride, and the polyethylene grafted maleic anhydride is compounded with a compound antioxidant, an anti-ultraviolet agent, cis-cypermethrin, piperonyl butoxide, Fischer-Tropsch wax, nano calcium carbonate, linear low-density polyethylene and high-density polyethylene. The high-strength anti-aging insect-resistant polyethylene composite material is prepared by adopting a melt blending and extrusion molding method. The obtained high-strength anti-aging insect-resistant polyethylene composite material has excellent mechanical property, anti-aging property and insect-resistant property, the mechanical property is good after aging, and certain insect-resistant property is still kept.

Description

Technical Field

[0001] The present invention belongs to the technical field of plastic processing, and particularly relates to a high-strength, aging-resistant and insect-resistant polyethylene composite material and a preparation method thereof. Background Art

[0002] Polyethylene (PE for short) is a thermoplastic resin obtained by polymerizing ethylene. Polyethylene is usually a colorless or light yellow waxy solid particle, with good transparency, low density, generally between 0.91 - 0.96 g / cm 3 and has a relatively low melting point, generally around 105°C - 135°C, which makes it relatively easy to form during processing, and has relatively stable chemical properties and excellent electrical insulation performance.

[0003] Polyethylene has both a crystalline structure and an amorphous structure, which interpenetrate each other, resulting in the coexistence of crystalline regions and amorphous regions. The crystalline part gives the material higher mechanical strength, while the amorphous region endows the material with flexibility and elasticity. The degree of crystallinity depends on the degree of branching of the molecular chain and the polymerization conditions. Low-density polyethylene (LDPE) has a relatively loose molecular chain structure, with many long branches and a low degree of crystallinity, generally around 55% - 65%. Its molecular chain has good flexibility and relatively weak intermolecular forces. LDPE has good softness, extensibility and transparency, but relatively low strength. It has good low-temperature resistance and can still maintain a certain degree of flexibility in a low-temperature environment and is not easily brittle. High-density polyethylene (HDPE) has a regular molecular chain structure, fewer branches and a high degree of crystallinity, generally around 80% - 90%. The molecular chains are arranged closely, and the intermolecular forces are strong. HDPE has higher strength, hardness and rigidity, and also has good wear resistance and heat resistance. Its chemical corrosion resistance and electrical insulation performance are excellent, but its flexibility is relatively poor.

[0004] Nano-titanium dioxide usually appears as a white powder, with a particle size generally between 10 - 100 nanometers, having dispersibility, a relatively high specific surface area and a small grain size. The molecular formula of nano-titanium dioxide is TiO2, and its crystal structure mainly has two types: anatase type and rutile type. Rutile TiO2 belongs to the tetragonal crystal system, and its crystal structure is more compact than that of the anatase type. Oxygen atoms are arranged in a hexagonal close-packed manner, and titanium atoms are located in the octahedral interstitial sites of oxygen. This structure makes nano-titanium dioxide have a relatively high specific surface area and many surface active sites, thus showing excellent performance in photocatalysis and other aspects. It can absorb ultraviolet light and generate reactive oxygen free radicals, and these free radicals can react with organic pollutants on the material surface and decompose them into harmless substances. At the same time, nano-titanium dioxide can generate photo-generated electrons and holes under light irradiation, and these photo-generated carriers can react with oxygen and water to generate reactive oxygen free radicals, such as hydroxyl radicals (OH) and superoxide radicals (O2- ) These free radicals have strong oxidizing properties and can also decompose organic pollutants on the material surface, thereby reducing the erosion of organic pollutants on the material and achieving a certain anti-aging effect. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength, anti-aging and anti-insect polyethylene composite material and its preparation method, which has good anti-insect effects, mechanical properties, processing properties, and at the same time has good anti-aging properties.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A high-strength, anti-aging and anti-insect polyethylene composite material, the raw materials are calculated by weight: 10 parts of high-strength, anti-aging and anti-insect polyethylene composite masterbatch, 90 parts of high-density polyethylene; the raw materials of the high-strength, anti-aging and anti-insect polyethylene composite masterbatch are calculated by weight: 1 part of antioxidant, 1 part of ultraviolet light absorber, 2-4 parts of anti-aging agent, 1 part of polyethylene grafted maleic anhydride, 8 parts of cis-permethrin, 4 parts of piperonyl butoxide, 5 parts of Fischer-Tropsch wax, 10 parts of nano calcium carbonate, 20 parts of high-density polyethylene, 45 parts of linear low-density polyethylene.

[0008] Furthermore, the antioxidant is a compound of tris(2,4-di-tert-butylphenyl) phosphite and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] with a mass ratio of 1:1, the ultraviolet light absorber is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, and the anti-aging agent is modified nano-titanium dioxide.

[0009] Furthermore, the preparation steps of the modified nano-titanium dioxide are as follows: (1) Add silane coupling agent KH540 to the ethanol solution, stir and then ultrasonicate for 30 min to make the silane coupling agent evenly dispersed; (2) Place the solution obtained in step (1) in an 80°C water bath, slowly add rutile nano-titanium dioxide while stirring, continue to stir for 2 h, then stir at room temperature for 6 h. After the reaction is completed, filter by suction, and vacuum dry the precipitate for 8 h to obtain the modified nano-titanium dioxide. Among them, the dosage of silane coupling agent KH540 is 10% of the mass of rutile nano-titanium dioxide. The mass concentration of the ethanol solution is 95%.

[0010] Further, the preparation steps of the polyethylene grafted maleic anhydride are as follows: (1) Stir 5 parts of maleic anhydride, 4 parts of acrylic acid, 0.3 parts of diisopropylbenzene peroxide and 100 parts of high-density polyethylene evenly by mass; (2) Add 3 parts of L-cysteine and 3 parts of 2-methylbenzenethiol to the mixture obtained in step (1), and stir evenly; (3) Granulate the mixture obtained in step (2) by extrusion to obtain the polyethylene grafted maleic anhydride; The temperature of each zone of the twin-screw extruder: the first zone is 130 °C, the second zone is 135 °C, the third zone is 140 °C, and the fourth to seventh zones are all 150 °C, and the rotation speed is 100 r / min.

[0011] A method for preparing the high-strength, aging-resistant and insect-resistant polyethylene composite material as described above includes the following steps: (1) Mix an antioxidant, an anti-ultraviolet agent, an anti-aging agent, polyethylene grafted maleic anhydride, cis-permethrin, piperonyl butoxide, Fischer-Tropsch wax, nano-calcium carbonate, high-density polyethylene and linear low-density polyethylene evenly and then extrude and granulate to obtain a high-strength, aging-resistant and insect-resistant polyethylene composite masterbatch; (2) Mix the high-strength, aging-resistant and insect-resistant polyethylene composite masterbatch and high-density polyethylene, stir evenly and then extrude and granulate to obtain the high-strength, aging-resistant and insect-resistant polyethylene composite material. Among them, the temperature of each zone of the twin-screw extruder during extrusion and granulation is 160 °C - 200 °C, and the rotation speed is 200 - 400 r / min.

[0012] The beneficial effects of the present invention are as follows:

[0013] (1) The present invention uses environmentally friendly nano-titanium dioxide and KH540 silane coupling agent as raw materials to prepare a modified titanium dioxide anti-aging agent, and uses it together with an antioxidant obtained by compounding tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) and pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), Fischer-Tropsch wax, and nano-calcium carbonate. The prepared high-strength, aging-resistant and insect-resistant polyethylene composite material has the benefits of health and environmental protection in the raw material preparation process and still has excellent mechanical properties.

[0014] (2) The high-strength, aging-resistant and insect-resistant polyethylene composite material prepared by the present invention adopts a two-step method of first preparing the masterbatch and then the finished product in the preparation process. Therefore, the proportion of pesticides in the final high-strength, aging-resistant and insect-resistant polyethylene composite material can be accurately controlled. When directly mixing low-concentration additives such as piperonyl butoxide and antioxidants, due to their low content, they may be lost during the processing due to volatilization, degradation or adhesion to the surface of the equipment. However, through the two-step method, these additives can be uniformly dispersed in the masterbatch in advance to ensure the proportion of these additives in the finished product. At the same time, since fine powder-like linear low-density polyethylene is selected as the masterbatch matrix at the raw material level, which has better mixing characteristics than conventional granular polyethylene, the filler can be more uniformly dispersed therein after physical mixing. Combining with modified nano-titanium dioxide and polyethylene grafted maleic anhydride can improve the compatibility between the filler and the matrix; and the fine powder-like linear low-density polyethylene can effectively absorb liquid piperonyl butoxide, ensuring that during the process of extrusion granulation using a twin-screw extruder, piperonyl butoxide will not be lost through tiny gaps, effectively improving the retention of pesticides in the high-strength, aging-resistant and insect-resistant polyethylene composite material after extrusion granulation, avoiding the disadvantages that the insect-resistant components are easily lost in the matrix and have poor compatibility with the matrix, and maintaining good mechanical properties and insect-resistant properties.

[0015] (3) The high-strength, aging-resistant and insect-resistant polyethylene composite material prepared by the present invention adopts a two-step method of first preparing the masterbatch and then the finished product in the preparation process. To ensure the compatibility between high-density polyethylene and linear low-density polyethylene, polyethylene grafted maleic anhydride is added to fully improve the compatibility between high-density polyethylene and linear low-density polyethylene. In the structure of the polyethylene grafted maleic anhydride prepared by the present invention, high-density polyethylene is used as the main body and maleic anhydride acts as a compatibilizer. Due to the addition of maleic anhydride, two different types of polyethylene with quite different physical properties can have better compatibility, and at the same time, the dispersion of Fischer-Tropsch wax and nano-calcium carbonate in the matrix is improved; finally, the high-strength, aging-resistant and insect-resistant polyethylene composite material prepared by the present invention not only has good filler dispersion performance, but also maximally improves the mechanical properties of the composite material. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 SEM diagram of the modified nano-titanium dioxide prepared by the present invention.

[0017] Figure 2 Infrared spectra of nano-titanium dioxide before and after modification. DETAILED DESCRIPTION OF THE INVENTION

[0018] In order to make the content described in the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

[0019] The high-density polyethylene and linear low-density polyethylene in the following examples were all purchased from Sinopec Fujian Refining & Chemical Co., Ltd. Cis-permethrin and piperonyl butoxide were both purchased from Jiangsu Yangnong Chemical Co., Ltd. Nano-TiO2 and KH540 were both purchased from Macklin Biochemical Technology Co., Ltd.

[0020] The preparation method of the modified nano-titanium dioxide anti-aging agent in the following examples includes the following steps:

[0021] (1) Weigh 15 g of nano-TiO2 powder with an electronic balance, then pour it into a 500 mL three-necked flask containing 250 mL of absolute ethanol, and oscillate the solution with ultrasonic waves for 30 minutes. Pipette 1.5 mL of KH540 from the burette with a small beaker, then add 50 mL of absolute ethanol and 2 mL of deionized water, and ultrasonically oscillate for hydrolysis for 15 minutes. Dropwise add the hydrolyzed KH540 solution into the 500 mL three-necked flask, and then ultrasonically oscillate for another 30 minutes.

[0022] (2) Place the solution in the three-necked flask in a constant temperature water bath, heat it in a water bath at 80 °C for 2 hours, and after the reaction, vacuum filter and dry the solution. Wrap the dried powder with filter paper, vacuum dry it in a vacuum drying oven at 60 °C for 8 h, and grind the modified nano-particles with an agate mortar to obtain the treated TiO2-KH540.

[0023] Figure 1 This is the SEM image of the modified nano-titanium dioxide TiO2-KH540 prepared by the present invention. It can be seen that KH540 is more evenly dispersed on TiO2, which is more conducive to the combination of TiO2 and the matrix resin, making the performance of the material more excellent. Figure 2 These are the infrared spectra of TiO2 before and after modification. Among them, a is the infrared spectrum of TiO2 before modification, and b is the infrared spectrum of TiO2 after modification. After comparing them, it can be found that the modified nano-titanium dioxide has obvious characteristic absorption peaks at 2956 cm -1 , 2807 cm -1 , 1695 cm -1 , 1338 cm -1 . Among them, the absorption peaks at 2956 cm -1 , 2807 cm -1 represent the asymmetric stretching vibration of C-H, and the absorption peak at 1695 cm -1 represents the stretching vibration peak of C=O. Thus, it can be proved that the coupling agent KH540 exists on the nano-titanium dioxide. In summary, according to the analysis of the infrared spectrum, it can be inferred that the coupling agent KH540 has been successfully grafted onto the surface of the nano-titanium dioxide.

[0024] The preparation method of polyethylene grafted maleic anhydride in the following examples includes the following steps:

[0025] (1) Stir 5 parts of maleic anhydride, 4 parts of acrylic acid, 0.3 part of diisopropylbenzene peroxide and 100 parts of high-density polyethylene thoroughly and evenly.

[0026] (2) Add 3 parts of L-cysteine and 3 parts of 2-methylbenzenethiol to the mixture obtained in step (1), and stir.

[0027] (3) Extrude and pelletize the mixture obtained in step (2) through a twin-screw extruder. Set the base temperature of the twin-screw extruder as zone 1: 130 °C, zone 2: 135 °C, zone 3: 140 °C, and zones 4 to 7: 150 °C. Set the rotation speed of the extruder as 100 r / min. After extrusion and pelletization, polyethylene grafted maleic anhydride is obtained.

[0028] The compound antioxidant in the following examples is obtained by mixing tris(2,4-di-tert-butylphenyl) phosphite (antioxidant 168) and pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] (antioxidant 1010) evenly at a mass ratio of 1:1.

[0029] Example 1

[0030] A preparation method of a high-strength, aging-resistant and insect-resistant polyethylene composite material:

[0031] 1) The high-strength, aging-resistant and insect-resistant polyethylene composite masterbatch includes, by weight parts: 1 part of compound antioxidant, 1 part of ultraviolet absorber, 2 parts of anti-aging agent modified nano-titanium dioxide, 1 part of polyethylene grafted maleic anhydride, 8 parts of cis-permethrin, 4 parts of piperonyl butoxide, 5 parts of Fischer-Tropsch wax, 10 parts of nano-calcium carbonate, 20 parts of high-density polyethylene, and 45 parts of linear low-density polyethylene. After thoroughly stirring and mixing, use a twin-screw extruder to extrude and pelletize to obtain the masterbatch, where the temperature of each zone of the extruder is set as 160 °C and the rotation speed is 200 r / min.

[0032] 2) Weigh 10 parts of the masterbatch prepared in step 1), and add another 90 parts of high-density polyethylene. After thorough stirring and mixing, use a twin-screw extruder to extrude and pelletize to obtain the high-strength, aging-resistant and insect-resistant polyethylene composite material. The temperature of each zone during extrusion and pelletization is 165 °C, and the rotation speed is set as 200 r / min.

[0033] Example 2

[0034] A preparation method of a high-strength, aging-resistant and insect-resistant polyethylene composite material:

[0035] (1) The high-strength, aging-resistant and insect-resistant polyethylene composite masterbatch comprises, by weight: 1 part of compound antioxidant, 1 part of UV inhibitor, 3 parts of anti-aging agent modified nano titanium dioxide, 1 part of polyethylene grafted maleic anhydride, 8 parts of cis-cypermethrin, 4 parts of piperonyl butoxide, 5 parts of Fischer-Tropsch wax, 10 parts of nano calcium carbonate, 20 parts of high-density polyethylene, and 45 parts of linear low-density polyethylene. After being fully stirred and mixed, a twin-screw extruder is used to extrude and granulate to obtain a masterbatch, wherein the temperature of each zone of the extruder is set to 160°C and the speed is 200r / min.

[0036] (2) Weigh 10 parts of the masterbatch prepared in step (1), add 90 parts of high-density polyethylene, stir and mix thoroughly, and use a twin-screw extruder to granulate through extrusion to obtain the high-strength, aging-resistant and insect-resistant polyethylene composite material. The temperature of each zone in the extrusion granulation is 165° C., and the rotation speed is 200 r / min.

[0037] Example 3

[0038] A preparation method of a high-strength, aging-resistant and insect-resistant polyethylene composite material:

[0039] (1) The high-strength, aging-resistant and insect-resistant polyethylene composite masterbatch comprises, by weight: 1 part of compound antioxidant, 1 part of anti-ultraviolet agent, 4 parts of anti-aging agent modified nano titanium dioxide, 1 part of polyethylene grafted maleic anhydride, 8 parts of cis-cypermethrin, 4 parts of piperonyl butoxide, 5 parts of Fischer-Tropsch wax, 10 parts of nano calcium carbonate, 20 parts of high-density polyethylene, and 45 parts of linear low-density polyethylene. After being fully stirred and mixed, a twin-screw extruder is used to extrude and granulate to obtain a masterbatch, wherein the temperature of each zone of the extruder is set to 160°C and the speed is 200r / min.

[0040] (2) Weigh 10 parts of the masterbatch prepared in step (1), add 90 parts of high-density polyethylene, stir and mix thoroughly, and use a twin-screw extruder to granulate through extrusion to obtain the high-strength, aging-resistant and insect-resistant polyethylene composite material. The temperature of each zone in the extrusion granulation is 165° C., and the rotation speed is 200 r / min.

[0041] Comparative Example 1

[0042] 90 parts of high-density polyethylene and 10 parts of linear low-density polyethylene were extruded and granulated using a twin-screw extruder to obtain pure polyethylene material. The temperature of each zone in the extrusion granulation was 165°C and the rotation speed was 200r / min.

[0043] The samples obtained in the embodiments and comparative examples were subjected to performance tests, and the results are shown in Table 1.

[0044] Aging experiment: After obtaining the high-strength, aging-resistant and insect-resistant polyethylene composite material, the samples prepared by injection molding are first stabilized at room temperature for 24 hours, and then fixedly placed in a damp and heat alternating tester for aging test, and then tested after aging. Test conditions: working temperature range: 0°C to 80°C; working humidity range: 20%RH to 90%RH; heating and cooling rate: 1°C / min; humidity change rate: 3%RH / min; each cycle is usually 24 hours, and the total number of cycles is 10 times. The results are shown in Table 1.

[0045] Table 1 Test results of sample performance

[0046]

[0047] The data in Table 1 show that when the modified nano-titanium dioxide is 4 parts, the tensile strength of the sample can reach 38.54 MPa, and the elongation at break can reach 629.59%, which are increased by 47.07% and 32.65% respectively compared with the comparative example. At the same time, after the aging experiment, the pesticide content only decreases by 35.33%, and the tensile strength and elongation at break only decrease by 12.95% and 17.35% respectively. And with the increase of the addition amount of the modified nano-titanium dioxide, the tensile strength and elongation at break of the sample also have a certain increase. The high-strength, aging-resistant and insect-resistant polyethylene composite material prepared by the present invention has good insect resistance, mechanical properties and processing properties, and at the same time has good aging resistance.

[0048] The above are only the preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims

1. A high-strength, aging-resistant and insect-resistant polyethylene composite material, characterized in that: The raw materials are by weight: 10 parts of high-strength, aging-resistant and insect-resistant polyethylene composite masterbatch and 90 parts of high-density polyethylene; the raw materials of the high-strength, aging-resistant and insect-resistant polyethylene composite masterbatch are by weight: 1 part of antioxidant, 1 part of ultraviolet light absorber, 2 - 4 parts of anti-aging agent, 1 part of polyethylene grafted maleic anhydride, 8 parts of cis-permethrin, 4 parts of piperonyl butoxide, 5 parts of Fischer-Tropsch wax, 10 parts of nano calcium carbonate, 20 parts of high-density polyethylene, and 45 parts of linear low-density polyethylene.

2. The high-strength, aging-resistant and insect-resistant polyethylene composite material according to claim 1, wherein: The antioxidant is a compound of tris(2,4-di-tert-butylphenyl) phosphite and pentaerythritol tetrakis [β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate] with a mass ratio of 1:1, the ultraviolet light absorber is bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, and the anti-aging agent is modified nano-titanium dioxide.

3. The high-strength, aging-resistant and insect-resistant polyethylene composite material according to claim 2, wherein: The preparation steps of the modified nano-titanium dioxide are as follows: (1) Add silane coupling agent KH540 to the ethanol solution, stir and then ultrasonicate for 30 min to disperse the silane coupling agent evenly. (2) Place the solution obtained in step (1) in an 80°C water bath, slowly add rutile nano-titanium dioxide while stirring, continue stirring for 2 h, then stir at room temperature for 6 h. After the reaction is completed, filter by suction, and vacuum dry the precipitate for 8 h to obtain the modified nano-titanium dioxide.

4. The high-strength, aging-resistant and insect-resistant polyethylene composite material according to claim 3, wherein: The dosage of silane coupling agent KH540 is 10% of the mass of rutile nano-titanium dioxide.

5. The high-strength, aging-resistant and insect-resistant polyethylene composite material according to claim 3, wherein: In step (1), the mass concentration of the ethanol solution is 95%.

6. The high-strength, aging-resistant and insect-resistant polyethylene composite material according to claim 1, wherein: The preparation steps of the polyethylene grafted maleic anhydride are as follows: (1) By weight, uniformly stir 5 parts of maleic anhydride, 4 parts of acrylic acid, 0.3 part of diisopropylbenzene peroxide, and 100 parts of high-density polyethylene. (2) Add 3 parts of L-cysteine and 3 parts of 2-methylbenzenethiol to the mixture obtained in step (1), and stir evenly. (3) Granulate the mixture obtained in step (2) by extrusion to obtain the polyethylene grafted maleic anhydride; the temperatures of each zone of the twin-screw extruder are: zone 1 at 130°C, zone 2 at 135°C, zone 3 at 140°C, and zones 4 to 7 at 150°C, and the rotation speed is 100 r / min.

7. A method for preparing the high-strength, aging-resistant and insect-resistant polyethylene composite material according to any one of claims 1-6, characterized in that: It includes the following steps: (1) Mix the antioxidant, ultraviolet light absorber, anti-aging agent, polyethylene grafted maleic anhydride, cis-permethrin, piperonyl butoxide, Fischer-Tropsch wax, nano calcium carbonate, high-density polyethylene, and linear low-density polyethylene evenly and then extrude and granulate to obtain the high-strength, aging-resistant and insect-resistant polyethylene composite masterbatch. (2) Mix the high-strength, aging-resistant and insect-resistant polyethylene composite masterbatch and high-density polyethylene, stir evenly and then extrude and granulate to obtain the high-strength, aging-resistant and insect-resistant polyethylene composite material.

8. The method according to claim 7, characterized in that: In the extrusion granulation, the temperatures of each zone of the twin-screw extruder are all 160°C - 200°C, and the rotation speed is 200 - 400 r / min.

Images