Preparation method of ultra-high molecular weight polyethylene composition

Abstract

The invention discloses a preparation method of an ultra-high molecular weight polyethylene composition, which comprises the following steps: 1) uniformly mixing ultra-high molecular weight polyethylene resin, a hindered amine stabilizer and a part of antioxidant to obtain a premixed composition; and 2) after the premixed composition is irradiated by a 15-50Kgy high-energy electron beam or a cobalt source, adding the rest antioxidant and peroxide to obtain the ultra-high molecular weight polyethylene composition. Compared with the prior art, through irradiation modification, the addition amount of peroxide in the ultra-high molecular weight polyethylene composition is reduced, the crosslinking efficiency is improved, adverse effects caused by too high addition amount of peroxide are avoided, and meanwhile, the wear resistance and heat resistance of the ultra-high molecular weight polyethylene composition are improved. The ultra-high molecular weight polyethylene composition can be used for manufacturing wear-resistant and pressure-resistant pipes, wear-resistant plates and the like with high heat resistance.

Description

Technical Field

[0001] The invention relates to the field of polymer technology, and in particular to a method for preparing an ultra-high molecular weight polyethylene composition. Background Art

[0002] Ultra High Molecular Weight Polyethylene (UHMWPE) is a linear thermoplastic engineering plastic with good impact resistance, strong wear resistance, good corrosion resistance and self-lubrication. It is widely used in transportation, agriculture, chemical industry, petroleum, machinery, construction, papermaking, packaging, textile, food, electrical, medical and sports. At present, the largest consumption area of ​​UHMWPE in China is the production of sheets, profiles and pipes. However, poor creep resistance and low heat deformation temperature greatly limit the application of UHMWPE. Since products based on UHMWPE are easy to deform, especially under high temperature or stress conditions, the creep resistance is worse. Therefore, in order to broaden the application scope of UHMWPE, it is very important to improve the thermal stability and creep resistance of UHMWPE.

[0003] The slow migration of molecular chains is an intrinsic factor for the poor creep properties of UHMWPE. Reducing the movement of molecular chains can also bring about changes in other properties, such as improving the thermal stability of UHMWPE. The traditional method is to enhance the intermolecular forces through particle filling and blending modification, thereby improving the creep resistance of UHMWPE, but the effect is not good; moreover, because UHMWPE itself has a high viscosity, particle filling and blending modification methods increase the difficulty of UHMWPE processing technology. At present, radiation cross-linking modification and chemical cross-linking modification (mainly peroxide cross-linking modification) are the two main means of modifying UHMWPE through cross-linking. However, the chemical cross-linking method has a high content of cross-linking agent peroxide, which produces adverse effects such as volatile substances and odor. Radiation cross-linking is considered to be a simple and effective method to improve the performance of various polymers. Under normal conditions, irradiation can cause polyethylene resin to cross-link and polypropylene resin to degrade; however, using high-dose gamma rays or electron beams to irradiate the PE-UHMW surface will cause it to oxidize and age, and produce a large number of free radicals, which will seriously affect the mechanical properties, stability and wear resistance of the product; and using rays with lower irradiation doses will cause the cross-linking density to decrease simultaneously, and the expected modification effect will not be achieved.

[0004] For example, Chinese patent document CN111135343A discloses a highly cross-linked and highly antioxidant-doped artificial joint prosthesis material and its preparation method. Organic peroxide is used as a chemical cross-linking agent, and the organic peroxide cross-linking agent accounts for 0.5% to 3% of the total mass of the polyphenol antioxidant, ultra-high molecular weight polyethylene and the organic peroxide cross-linking agent, which improves the cross-linking density of the ultra-high molecular weight polyethylene material stabilized by the high-content polyphenol antioxidant, and at the same time, a higher amount of polyphenol added makes the material have better oxidation stability.

[0005] Chinese patent document CN115746344A discloses an ultra-high molecular weight polyethylene product and its preparation method and application. The ultra-high molecular weight polyethylene and functional masterbatch are mixed to obtain a mixture, and the ultra-high molecular weight polyethylene product is obtained by hot pressing under vibration, wherein the functional masterbatch contains 100 parts by weight of polyethylene, 0.3-5 parts by weight of a cross-linking agent, and 2-30 parts by weight of a cross-linking auxiliary agent.

[0006] In order to improve the crosslinking efficiency, Chinese patent document CN1749303A uses infrared irradiation equipment to irradiate and crosslink a polyethylene resin composition to which a peroxide crosslinking agent, an auxiliary crosslinking agent, an antioxidant, and a lubricant are added to form crosslinked polyethylene pipes and wire and cable products.

[0007] Chinese patent document CN101848968A discloses the introduction of hindered amine light stabilizer (HALS) into HMWPE resin, and crosslinking the (U)HMWPE during or after the molding of the (U)HMWPE resin. First, the HALS is introduced into the (U)HMWPE resin by mixing the HALS with the (U)HMWPE resin or the (U)HMWPE melt, or by impregnating the (U)HMWPE resin with a HALS solution, or by spraying the HALS solution onto the (U)HMWPE resin, or by adding HALS to the (U)HMWPE melt. An initiator such as a peroxide may also be added, and an active auxiliary agent may be optionally added. The (U)HMWPE resin containing the HALS is then molded to obtain a product. Finally, the product is crosslinked and sterilized by gamma radiation or electron beam radiation to obtain an artificial medical implant. This disclosed technology prepares artificial medical implants by radiation crosslinking, which is not applicable to products such as large pipes and sheets, and there is still a need for an ultra-high molecular weight polyethylene composition that can be directly processed and molded on existing equipment.

[0008] In summary, the existing chemical cross-linking method has a high content of cross-linking agent peroxide, produces volatile substances and odor, etc. The modification of ultra-high molecular weight polyethylene by radiation cross-linking requires irradiation of the product, which is not applicable to products such as large pipes and plates. Summary of the invention

[0009] In view of the problems existing in the prior art and the directions for improvement, the present invention provides a method for preparing an ultra-high molecular weight polyethylene composition, which comprises first mixing an ultra-high molecular weight polyethylene resin, a part of an antioxidant and a hindered amine stabilizer, and then irradiating the mixture at a specific irradiation dose to obtain a composition that is easy to chemically crosslink, and then adding the remaining antioxidant and peroxide for chemical crosslinking, thereby significantly reducing the amount of peroxide used and overcoming the problems of the existing chemical crosslinking method, such as high peroxide content in the crosslinking agent, easy generation of volatile substances and odor, and the like.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] A method for preparing an ultra-high molecular weight polyethylene composition, characterized in that it comprises the following steps:

[0012] 1) uniformly mixing an ultra-high molecular weight polyethylene resin, a hindered amine stabilizer, and a portion of an antioxidant to obtain a premixed composition;

[0013] 2) After the premixed composition is irradiated with a high-energy electron beam or a cobalt source at 15 to 50 Kgy, the remaining antioxidant and peroxide are added to obtain the ultra-high molecular weight polyethylene composition.

[0014] Optionally, in the method for preparing the ultra-high molecular weight polyethylene composition recommended by the present invention, the irradiation dose is 20 to 40 KGy.

[0015] Optionally, in the method for preparing the ultra-high molecular weight polyethylene composition provided by the present invention, the mass ratio of the antioxidant in step 1) to the antioxidant in step 2) is 1:0.35-4; preferably 1:1-2.5.

[0016] Optionally, in the preparation method of the above-mentioned ultra-high molecular weight polyethylene composition provided by the present invention, based on 100 parts by weight of the ultra-high molecular weight polyethylene resin, the hindered amine stabilizer is 0.01 to 0.05 parts by weight, the antioxidant is 0.4 to 0.8 parts by weight and the peroxide is 0.03 to 0.2 parts by weight.

[0017] Optionally, in the preparation method of the ultra-high molecular weight polyethylene composition recommended by the present invention, the ultra-high molecular weight polyethylene resin can be a commercially available product or can be polymerized from ethylene; the specific polymerization production process is similar to the production process of ordinary high-density polyethylene, both of which use ZN catalysts to polymerize ethylene under certain conditions. Domestic ultra-high molecular weight polyethylene is mainly based on the third-generation ZN catalyst. During polymerization, catalysts and ethylene are added to the reactor, and ultra-high molecular weight polyethylene is obtained through polymerization reaction. Depending on whether the reaction is continuous, it is divided into a continuous polymerization process and an intermittent polymerization process. At present, most industrial devices for producing ultra-high molecular weight polyethylene use slurry polymerization, and the slurry process mainly includes a stirred tank process and a ring pipe process.

[0018] For example, the method for producing ultra-high molecular weight polyethylene resin using a conventional slurry process is as follows: high-purity ethylene is subjected to coordination polymerization in an alkane solvent, under the initiation of a ZN catalyst and an alkyl aluminum co-catalyst, at 0.3-0.8 MPa and 65-85°C to obtain an ultra-high molecular weight polyethylene resin.

[0019] Optionally, in the method for preparing the ultra-high molecular weight polyethylene composition recommended by the present invention, the viscosity-average molecular weight of the ultra-high molecular weight polyethylene resin is 1.5 to 5 million, and the apparent density is 0.35 to 0.50 g / cm 3 , the average particle size is 70 to 300 microns.

[0020] Optionally, in the preparation method of the ultra-high molecular weight polyethylene composition recommended by the present invention, the hindered amine stabilizer is selected from bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate (GW-770), bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate (GW-123), 2,2,6,6-tetramethyl-4-piperidinyl stearate (GW-3853), poly{(6-morpholinyl-5-triazine-2,4-diyl)(2,2,6,6-tetramethylpiperidinyl)iminohexamethylene[(2,2,6,6-tetramethylpiperidinyl)-imino]} (GW-3346), poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2,6,6,-tetramethyl-piperidinyl)imino]} any one of: poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinyl)imino)-1,6-hexanediamine [(2,2,6,6-tetramethyl-4-piperidinyl)imino]} (GW-944), poly(4-hydroxy-2,2,6,6-tetramethyl-1-piperidinylethanol) succinate (GW-622), high molecular weight triazine-piperidine condensate (GW-119), polymer of the reaction product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and 2,4,6-trichloro-1,3,5-triazine, N-butyl-1-butylamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine, and polymer containing polymerized segments of 2,2,6,6-tetramethylpiperidinol-4-methacrylate (TMPM) and / or 1,2,2,6,6-pentamethylpiperidinol-4-methacrylate (PMPM);

[0021] Among them, the polymer containing the polymerized fragments of 2,2,6,6-tetramethylpiperidinol-4-methylacrylate (TMPM) and / or 1,2,2,6,6-pentamethylpiperidinol-4-methylacrylate (PMPM) refers to a polymer containing -(TMPM)m-structural units and / or -(PMPM)m-structural units, where m is 4 to 100. The specific method of homopolymerization or copolymerization of TMPM and PMPM can be conventional in the industry, such as mixing an initiator, monomer TMPM and / or PMPM, and a solvent, and polymerizing them under certain conditions to obtain the target product.

[0022] Optionally, in the preparation method of the ultra-high molecular weight polyethylene composition recommended by the present invention, the antioxidant includes a primary antioxidant, and the primary antioxidant is a phenolic antioxidant; preferably, the phenolic antioxidant is selected from at least one of 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene (antioxidant 330), β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1076), 4,4'-thiobis(6-tert-butyl-3-methylphenol) (antioxidant 300) and tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]pentaerythritol (antioxidant 1010).

[0023] Optionally, in the preparation method of the ultra-high molecular weight polyethylene composition recommended by the present invention, the antioxidant also includes a secondary antioxidant, and the secondary antioxidant is selected from any one of a phosphite antioxidant (such as tris(2,4-di-tert-butylphenyl)phosphite (antioxidant 168)), a hydrazide antioxidant (such as N,N'-bis[β(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine (antioxidant 1024)), and a thioester antioxidant (such as thiodipropionate, etc.); preferably, the mass ratio of the main antioxidant to the secondary antioxidant is 2 to 4:1.

[0024] Optionally, in the preparation method of the ultra-high molecular weight polyethylene composition recommended by the present invention, the peroxide is selected from at least one of tert-butyl peroxyisopropyl carbonate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(benzoylperoxide)hexane, tert-butyl peroxyacetate, di-tert-butyl diperoxyphthalate, tert-butyl peroxymaleic acid, cyclohexanone peroxide, tert-butyl peroxybenzoate, diisopropyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl peroxide isopropyl peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butyl-peroxy)hexane-3 and α,α'-bis-tert-butylperoxy-1,4-diisopropylbenzene.

[0025] Optionally, in the preparation method of the ultra-high molecular weight polyethylene composition provided by the present invention, the peroxide is usually added to the irradiated premixed composition in a liquid state, such as the peroxide can be added to the irradiated premixed composition by spraying, dipping or splashing; the peroxide and the remaining antioxidant cannot be added together, but the order of addition is not limited.

[0026] Optionally, the present invention also provides an application of an ultra-high molecular weight polyethylene composition obtained by the preparation method of the above-mentioned ultra-high molecular weight polyethylene composition in the preparation of pipes or plates; that is, the ultra-high molecular weight polyethylene composition is used to process wear-resistant pipes or plates, and if necessary, fillers such as carbon black can be added as needed when preparing the pipes.

[0027] When preparing pipes or tubes, existing equipment and existing process parameters can be used. For example, when preparing wear-resistant plates, the following methods can be used:

[0028] The ultra-high molecular weight polyethylene composition is added to a mold (existing molds can be used, such as a mold cavity with a length, width and height of 200 mm), and then the mold is placed in a flat vulcanizer that has been preheated to 210-230°C, and pressed at a temperature of 210-230°C and a pressure of 10-20MPa for 4-7 hours, and then the pressure is maintained at 10-20MPa, and the flat vulcanizer is cooled to below 40°C, and the plate is removed from the mold to obtain an ultra-high molecular weight polyethylene wear-resistant plate of corresponding thickness. Specifically, the corresponding mass of ultra-high molecular weight polyethylene composition can be added according to the required thickness.

[0029] For example, when preparing pipes, the following pipe extrusion conditions can be used: heating temperature is 220-240°C, die extrusion temperature is 230-250°C, extruder main screw speed is 110-140r / min, feeding speed is 150-200r / min, and pulling speed is 0.5-1.0m / min to obtain pipes of corresponding specifications. The specific specifications can be adjusted according to the actual specifications of the pipes and the quality of the added ultra-high molecular weight polyethylene composition.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. The preparation method of the ultra-high molecular weight polyethylene composition provided by the present invention is to first mix the ultra-high molecular weight polyethylene resin, part of the antioxidant and the hindered amine stabilizer, and then utilize the mutual synergistic effect between the components to irradiate at a high-energy electron beam or a cobalt source of 15 to 50 Kgy to obtain a composition that is not cross-linked (in the prior art, the purpose of irradiation is to achieve cross-linking) but has the characteristic of being easy to be micro-cross-linked, and finally add the remaining antioxidant and peroxide for chemical micro-cross-linking. Compared with the prior art, the amount of peroxide used during chemical cross-linking can be reduced, that is, the amount of peroxide added in the ultra-high molecular weight polyethylene composition can be reduced by irradiation modification, the cross-linking efficiency can be improved, and the adverse effects caused by excessive addition of peroxide can be avoided (overcoming the problem of high volatile matter content of cross-linking materials in the existing chemical cross-linking method), and the wear resistance and heat resistance of the ultra-high molecular weight polyethylene composition can be improved. The ultra-high molecular weight polyethylene composition prepared by the method can be processed into pipes and plates using existing pipe and plate production equipment to obtain pipes and plates with excellent appearance and performance, without increasing the equipment investment of the manufacturer, and after being placed for a long time, the appearance of products such as pipes and plates will not turn yellow.

[0032] 2. The preparation method of the ultra-high molecular weight polyethylene composition provided by the present invention can further improve the wear resistance and heat resistance of the ultra-high molecular weight polyethylene composition by further limiting the proportion of the antioxidant added in step 1) and step 2), as well as the amount of each component. DETAILED DESCRIPTION

[0033] The present invention is described in detail below by way of examples. It is necessary to point out that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Those skilled in the art in this field can make some non-essential improvements and adjustments to the present invention based on the above content of the present invention.

[0034] If no specific experimental steps or conditions are specified in the examples and comparative examples, the conventional experimental steps or conditions described in the literature in the art can be used. If no manufacturer is specified for the reagents or instruments used, they are all conventional reagent products that can be purchased commercially.

[0035] The intrinsic viscosity of ultra-high molecular weight polyethylene resin was tested according to GB / T 1632.3, and then the viscosity average molecular weight was calculated according to formula (1).

[0036] [M] = 5.37 × 10 4 [η] 1.37 ……………………………………(1)

[0037] The apparent density of the ultra-high molecular weight polyethylene resin is measured according to GB / T 1636, and the average particle size is obtained by measuring D50 using a laser particle size analyzer.

[0038] The yellowness index refers to the degree to which a plastic product deviates from white. A positive value indicates that the sample is yellow, and a negative value indicates that the sample is blue. The yellowness index can intuitively reflect the color condition of the product and is used to evaluate its aging performance. The yellowness index is determined according to ASTM E313.

[0039] The wear resistance is tested in accordance with SH / T 1818-2017, and the load deformation temperature is tested in accordance with GB / T1634.2.

[0040] Example 1

[0041] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0042] 1) Preparation of hindered amine stabilizer poly 2,2,6,6-tetramethylpiperidinol-4-methylacrylate: Azobisisobutyronitrile, 2,2,6,6-tetramethylpiperidinol-4-methylacrylate and acetone were added to a polymerization tube in sequence, mixed evenly, and then cooled with liquid nitrogen - vacuumed - nitrogen-thawed for 3 times, sealed under vacuum, and stirred at 76°C for 4 hours. The crude product was precipitated in n-hexane and dried to obtain poly 2,2,6,6-tetramethylpiperidinol-4-methylacrylate.

[0043] 2) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 2 million, apparent density 0.42 g / cm 3 , average particle size 150 μm), 0.01 parts by weight of the above-mentioned poly 2,2,6,6-tetramethylpiperidinol-4-methacrylate and 0.10 parts by weight of antioxidant 1010 are uniformly mixed to form a premixed composition;

[0044] 3) irradiating the above premixed composition with a cobalt source at a dose of 18 kGy to obtain a pre-irradiated composition; adding 0.12 parts by weight of di-tert-butyl peroxide to the pre-irradiated composition by spraying, and then mixing with 0.30 parts by weight of antioxidant 1010 to obtain an ultra-high molecular weight polyethylene composition.

[0045] 4) Processing the ultra-high molecular weight polyethylene composition into a wear-resistant plate, the specific method is as follows:

[0046] 2650g of ultra-high molecular weight polyethylene composition was added into a mold, the length, width and height of the mold cavity were all 200mm, the mold was placed in a flat-plate vulcanizer that had been preheated to 210°C, and pressed at a temperature of 210°C and a pressure of 10MPa for 6h, then the pressure was maintained at 10MPa, the flat-plate vulcanizer was cooled to below 40°C, the sheet was demoulded and taken out, and an ultra-high molecular weight polyethylene wear-resistant sheet with a thickness of 70mm was obtained.

[0047] Example 2

[0048] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0049] 1) Preparation of hindered amine stabilizer dodecyl poly 1,2,2,6,6-pentamethylpiperidinol-4-methacrylate: 2-cyano-2-propyl dodecyl trithiocarbonate, dibenzoyl peroxide, 1,2,2,6,6-pentamethylpiperidinol-4-methacrylate and acetone were added to a polymerization tube in sequence, and after uniform mixing, liquid nitrogen cooling-vacuuming-nitrogen passing-thawing were repeated 3 times, and the tube was sealed under vacuum, and stirred at 80° C. for 6 h. The obtained crude product was precipitated in methanol / water (v / v: 1 / 1), and after drying, dodecyl poly 1,2,2,6,6-pentamethylpiperidinol-4-methacrylate was obtained, wherein the degree of polymerization of the monomer 1,2,2,6,6-pentamethylpiperidinol-4-methacrylate was 60.

[0050] 2) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 1.7 million, apparent density 0.38 g / cm 3 , average particle size 75 microns), 0.03 weight parts of the above-mentioned dodecyl poly 1,2,2,6,6-pentamethylpiperidinol-4-methacrylate and 0.30 weight parts of antioxidant 1076 are mixed evenly to form a premixed composition;

[0051] 3) irradiating the above premixed composition with a cobalt source at a dose of 21 kGy to obtain a pre-irradiated composition; mixing the pre-irradiated composition and 0.20 parts by weight of antioxidant 1076 to obtain a mixture; and then adding 0.04 parts by weight of tert-butyl peroxide isopropylbenzene to the mixture by impregnation to obtain an ultra-high molecular weight polyethylene composition.

[0052] 4) The ultra-high molecular weight polyethylene composition is processed into a pipe. The pipe extrusion conditions are: heating temperature of 220° C., head extrusion temperature of 230° C., extruder main screw speed of 140 r / min, feed speed of 190 r / min, and traction speed of 1 m / min to obtain a pipe with a specification of φ110x10.

[0053] Example 3

[0054] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0055] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 2.3 million, apparent density 0.48 g / cm 3 , average particle size 89 microns), 0.02 parts by weight of GW-770 and 0.20 parts by weight of antioxidant 300 are mixed uniformly to form a premixed composition;

[0056] 2) irradiating the premixed composition with a cobalt source at a dose of 46 kGy to obtain a pre-irradiated composition; mixing the pre-irradiated composition with 0.40 parts by weight of antioxidant 300 to obtain a mixture, and then adding 0.19 parts by weight of tert-butyl peroxylaurate to the mixture in a splashing manner to obtain an ultra-high molecular weight polyethylene composition.

[0057] 3) Processing the ultra-high molecular weight polyethylene composition into a wear-resistant plate, the specific method is as follows:

[0058] 2250g of ultra-high molecular weight polyethylene composition was added to the mold, the length, width and height of the mold cavity were all 200mm, the mold was placed in a flat vulcanizer preheated to 220°C, pressed at 220°C and 15MPa for 5h, then the pressure was maintained at 15MPa, and the flat vulcanizer was cooled to below 40°C. The plate was demoulded and taken out to obtain an ultra-high molecular weight polyethylene wear-resistant plate with a thickness of 60mm.

[0059] Example 4

[0060] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0061] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 2.8 million, apparent density 0.45 g / cm 3 , average particle size 180 microns), 0.03 weight parts of GW-123 and 0.40 weight parts of composite antioxidant (the mass ratio of antioxidant 1010 to antioxidant 168 is 2:1) are mixed uniformly to form a premixed composition;

[0062] 2) The premixed composition is irradiated with a high-energy electron beam at a dose of 23 kGy to obtain a pre-irradiated composition; the pre-irradiated composition is uniformly mixed with 0.35 parts by weight of antioxidant 300 to obtain a mixture; and then 0.06 parts by weight of α,α'-bis-tert-butylperoxy-1,4-diisopropylbenzene is added to the mixture by spraying to obtain an ultra-high molecular weight polyethylene composition.

[0063] 3) The ultra-high molecular weight polyethylene composition is processed into a pipe, and the pipe extrusion conditions are: heating temperature is 230°C, head extrusion temperature is 240°C, extruder main screw speed is 130r / min, feeding speed is 170r / min, and pulling speed is 0.5m / min to obtain a pipe with a specification of φ325x15.

[0064] Example 5

[0065] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0066] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 3.5 million, apparent density 0.40 g / cm 3 , average particle size 260 microns), 0.05 weight parts of GW-3853 and 0.15 weight parts of composite antioxidant (the mass ratio of antioxidant 1010 to antioxidant 168 is 2:1) are mixed uniformly to form a premixed composition;

[0067] 2) The premixed composition is irradiated with a high-energy electron beam at a dose of 16 kGy to obtain a pre-irradiated composition; the pre-irradiated composition is uniformly mixed with 0.45 parts by weight of a composite antioxidant (the mass ratio of antioxidant 1076 to antioxidant 1024 is 4:1), and then 0.15 parts by weight of di-tert-butyl diperoxyphthalate is added in an impregnation manner to obtain an ultra-high molecular weight polyethylene composition.

[0068] 3) The ultra-high molecular weight polyethylene composition is processed into a pipe, and the pipe extrusion conditions are: heating temperature is 235°C, head extrusion temperature is 245°C, extruder main screw speed is 110r / min, feeding speed is 150r / min, and pulling speed is 0.6m / min to obtain a pipe with a specification of φ273x19.

[0069] Example 6

[0070] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0071] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 4.6 million, apparent density 0.44 g / cm 3 , average particle size 230 microns), 0.04 weight parts of GW-944 and 0.40 weight parts of composite antioxidant (the mass ratio of antioxidant 330 to thiodipropionate is 3:1) are mixed uniformly to form a premixed composition;

[0072] 2) The premixed composition is irradiated with a cobalt source at a dose of 35 kGy to obtain a pre-irradiated composition; 0.10 parts by weight of diisopropyl peroxide is added to the pre-irradiated composition by splashing, and then mixed evenly with 0.15 parts by weight of a composite antioxidant (the mass ratio of antioxidant 330 to thiodipropionate is 3:1) to obtain an ultra-high molecular weight polyethylene composition.

[0073] 3) Processing the ultra-high molecular weight polyethylene composition into a wear-resistant plate, the specific method is as follows:

[0074] 1500g of ultra-high molecular weight polyethylene composition was added into a mold, the length, width and height of the mold cavity were all 200mm, the mold was placed in a flat vulcanizer preheated to 225°C, pressed at 225°C and 17MPa for 4h, then the pressure was maintained at 17MPa, and the flat vulcanizer was cooled to below 40°C. The plate was demoulded and taken out to obtain an ultra-high molecular weight polyethylene wear-resistant plate with a thickness of 40mm.

[0075] Example 7

[0076] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0077] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 2.6 million, apparent density 0.41 g / cm 3 , average particle size 200 microns), 0.02 weight parts of GW-622 and 0.33 weight parts of composite antioxidant (antioxidant 1010: antioxidant 1076 mass ratio of 1:1) are mixed uniformly to form a premixed composition;

[0078] 2) The premixed composition is irradiated with a cobalt source at a dose of 30 kGy to obtain a pre-irradiated composition; 0.08 parts by weight of tert-butyl peroxy isopropyl carbonate is added to the pre-irradiated composition by impregnation, and then mixed evenly with 0.25 parts by weight of a composite antioxidant (the mass ratio of antioxidant 1010 to antioxidant 1076 is 1:1) to obtain an ultra-high molecular weight polyethylene composition.

[0079] 3) Add 6% carbon black to the ultra-high molecular weight polyethylene composition (based on the mass of the ultra-high molecular weight polyethylene composition, that is, the amount of carbon black added is 6% of the mass of the ultra-high molecular weight polyethylene composition), and process it into a pipe. The pipe extrusion conditions are: heating temperature of 225°C, head extrusion temperature of 235°C, extruder main screw speed of 120r / min, feeding speed of 160r / min, and traction speed of 0.8m / min to obtain a pipe with a specification of φ168x12.

[0080] Example 8

[0081] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0082] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 4 million, apparent density 0.46 g / cm 3 , average particle size 280 microns), 0.01 parts by weight of GW-3346 and 0.28 parts by weight of a composite antioxidant (the mass ratio of antioxidant 1076 to antioxidant 330 is 1:2) are mixed uniformly to form a premixed composition;

[0083] 2) The premixed composition is irradiated with a cobalt source at a dose of 48 kGy to obtain a pre-irradiated composition; 0.13 parts by weight of peroxide (the mass ratio of diisopropyl peroxide to tert-butyl peroxyisopropyl carbonate is 1:1) is added to the pre-irradiated composition by spraying, and then mixed evenly with 0.32 parts by weight of a composite antioxidant (the mass ratio of antioxidant 1076 to antioxidant 330 is 1:2) to obtain an ultra-high molecular weight polyethylene composition.

[0084] 3) Processing the ultra-high molecular weight polyethylene composition into a wear-resistant plate, the specific method is as follows:

[0085] 1880g of ultra-high molecular weight polyethylene composition was added into a mold, the length, width and height of the mold cavity were all 200mm, the mold was placed in a flat vulcanizer preheated to 215°C, pressed at 215°C and 13MPa for 7h, then the pressure was maintained at 13MPa, and the flat vulcanizer was cooled to below 40°C. The plate was demoulded and taken out to obtain an ultra-high molecular weight polyethylene wear-resistant plate with a thickness of 50mm.

[0086] Example 9

[0087] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0088] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 4 million, apparent density 0.46 g / cm 3 , average particle size 280 microns), 0.09 weight parts of GW-3346 and 0.09 weight parts of composite antioxidant (the mass ratio of antioxidant 1076 to antioxidant 330 is 1:2) are mixed uniformly to form a premixed composition;

[0089] 2) The premixed composition is irradiated with a cobalt source at a dose of 48 kGy to obtain a pre-irradiated composition; 0.13 parts by weight of peroxide (the mass ratio of diisopropyl peroxide to tert-butyl peroxyisopropyl carbonate is 1:1) is added to the pre-irradiated composition by spraying, and then mixed evenly with 0.43 parts by weight of a composite antioxidant (the mass ratio of antioxidant 1076 to antioxidant 330 is 1:2) to obtain an ultra-high molecular weight polyethylene composition.

[0090] 3) Processing the ultra-high molecular weight polyethylene composition into a wear-resistant plate, the specific method is as follows:

[0091] 1880g of ultra-high molecular weight polyethylene composition was added into a mold, the length, width and height of the mold cavity were all 200mm, the mold was placed in a flat vulcanizer preheated to 215°C, pressed at 215°C and 13MPa for 7h, then the pressure was maintained at 13MPa, and the flat vulcanizer was cooled to below 40°C. The plate was demoulded and taken out to obtain an ultra-high molecular weight polyethylene wear-resistant plate with a thickness of 50mm.

[0092] Example 10

[0093] This embodiment provides a method for preparing an ultra-high molecular weight polyethylene composition, and the specific steps are as follows:

[0094] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 4 million, apparent density 0.46 g / cm 3 , average particle size 280 microns), 0.07 parts by weight of GW-3346 and 0.45 parts by weight of a composite antioxidant (the mass ratio of antioxidant 1076 to antioxidant 330 is 1:2) are mixed uniformly to form a premixed composition;

[0095] 2) The premixed composition is irradiated with a cobalt source at a dose of 48 kGy to obtain a pre-irradiated composition; 0.13 parts by weight of peroxide (the mass ratio of diisopropyl peroxide to tert-butyl peroxyisopropyl carbonate is 1:1) is added to the pre-irradiated composition by spraying, and then mixed evenly with 0.09 parts by weight of a composite antioxidant (the mass ratio of antioxidant 1076 to antioxidant 330 is 1:2) to obtain an ultra-high molecular weight polyethylene composition.

[0096] 3) Processing the ultra-high molecular weight polyethylene composition into a wear-resistant plate, the specific method is as follows:

[0097] 1880g of ultra-high molecular weight polyethylene composition was added into a mold, the length, width and height of the mold cavity were all 200mm, the mold was placed in a flat vulcanizer preheated to 215°C, pressed at 215°C and 13MPa for 7h, then the pressure was maintained at 13MPa, and the flat vulcanizer was cooled to below 40°C. The plate was demoulded and taken out to obtain an ultra-high molecular weight polyethylene wear-resistant plate with a thickness of 50mm.

[0098] Comparative Example 1

[0099] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of Example 1, except that the irradiation step in step 3) is omitted. The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0100] 1) Preparation of hindered amine stabilizer poly 2,2,6,6-tetramethylpiperidinol-4-methylacrylate: the same as in Example 1.

[0101] 2) The preparation of the premixed composition is the same as in Example 1;

[0102] 3) 0.12 parts by weight of di-tert-butyl peroxide was added to the premixed composition by spraying, and then mixed evenly with 0.30 parts by weight of antioxidant 1010 to obtain an ultra-high molecular weight polyethylene composition.

[0103] 4) The ultra-high molecular weight polyethylene composition is processed into a wear-resistant plate in the same manner as in Example 1.

[0104] Comparative Example 2

[0105] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of Example 2, except that the irradiation dose in step 3) is different. The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0106] 1) Preparation of hindered amine stabilizer dodecyl poly 1,2,2,6,6-, pentamethylpiperidinol-4-methylacrylate: the same as in Example 2.

[0107] 2) The preparation of the premixed composition is the same as in Example 2;

[0108] 3) irradiating the premixed composition with a cobalt source at a dose of 11 kGy to obtain a pre-irradiated composition; uniformly mixing the pre-irradiated composition and 0.20 parts by weight of antioxidant 1076 to obtain a mixture; and then adding 0.04 parts by weight of tert-butyl peroxide isopropylbenzene to the mixture by impregnation to obtain an ultra-high molecular weight polyethylene composition.

[0109] 4) The ultra high molecular weight polyethylene composition was processed into a pipe in the same manner as in Example 2.

[0110] Comparative Example 3-1

[0111] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of Example 3, except that the irradiation dose in step 3) is different. The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0112] 1) The preparation of the premixed composition is the same as in Example 3;

[0113] 2) irradiating the premixed composition with a cobalt source at a dose of 60 kGy to obtain a pre-irradiated composition; mixing the pre-irradiated composition with 0.40 parts by weight of antioxidant 300 to obtain a mixture, and then adding 0.19 parts by weight of tert-butyl peroxylaurate to the mixture in a splashing manner to obtain an ultra-high molecular weight polyethylene composition.

[0114] 3) The ultra-high molecular weight polyethylene composition is processed into a wear-resistant plate in the same manner as in Example 3.

[0115] Comparative Example 3-2

[0116] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of comparative example 3-1, except that tert-butyl peroxylaurate is not added in step 2). The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0117] 1) The preparation of the premixed composition is the same as that of Comparative Example 3-1;

[0118] 2) irradiating the premixed composition with a cobalt source at a dose of 60 kGy to obtain a pre-irradiated composition; and uniformly mixing the pre-irradiated composition with 0.40 parts by weight of an antioxidant 300 to obtain an ultra-high molecular weight polyethylene composition.

[0119] 3) The ultra-high molecular weight polyethylene composition is processed into a wear-resistant plate in the same manner as in Comparative Example 3-1.

[0120] Comparative Example 4-1

[0121] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of Example 4, except that the hindered amine stabilizer GW-123 is not added in step 1). The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0122] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 2.8 million, apparent density 0.45 g / cm 3 , with an average particle size of 180 microns), 0.40 parts by weight of a composite antioxidant (the mass ratio of antioxidant 1010 to antioxidant 168 is 2:1) are mixed uniformly to form a premixed composition;

[0123] 2) The premixed composition is irradiated with a high-energy electron beam at a dose of 23 kGy to obtain a pre-irradiated composition; the pre-irradiated composition is uniformly mixed with 0.35 parts by weight of antioxidant 300 to obtain a mixture; and then 0.06 parts by weight of α,α'-bis-tert-butylperoxy-1,4-diisopropylbenzene is added to the mixture by spraying to obtain an ultra-high molecular weight polyethylene composition.

[0124] 3) The ultra high molecular weight polyethylene composition was processed into a pipe in the same manner as in Example 4.

[0125] Comparative Example 4-2

[0126] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of comparative example 4-1, except that α,α'-bis-tert-butylperoxide-1,4-diisopropylbenzene is not added in step 2). The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0127] 1) The preparation of the premixed composition is the same as that of Comparative Example 4-1;

[0128] 2) The premixed composition is irradiated with a high-energy electron beam at a dose of 23 kGy to obtain a pre-irradiated composition; the pre-irradiated composition is uniformly mixed with 0.35 parts by weight of an antioxidant 300 to obtain an ultra-high molecular weight polyethylene composition.

[0129] 3) The ultra-high molecular weight polyethylene composition was processed into a pipe in the same manner as in Comparative Example 4-1.

[0130] Comparative Example 5-1

[0131] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of Example 5, except that no antioxidant is added. The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0132] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 3.5 million, apparent density 0.40 g / cm 3 , average particle size 260 microns) and 0.05 parts by weight of GW-3853 were mixed to form a premixed composition;

[0133] 2) The premixed composition is irradiated with a high-energy electron beam at a dose of 16 kGy to obtain a pre-irradiated composition; and then 0.15 parts by weight of di-tert-butyl diperoxyphthalate is added to the pre-irradiated composition by dipping to obtain an ultra-high molecular weight polyethylene composition.

[0134] 3) The ultra high molecular weight polyethylene composition was processed into a pipe in the same manner as in Example 5.

[0135] Comparative Example 5-2

[0136] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of comparative example 5-1, except that di-tert-butyl diperoxyphthalate is not added in step 2). The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0137] 1) The preparation of the premixed composition is the same as that of Comparative Example 5-1;

[0138] 2) The premixed composition is irradiated with a high energy electron beam at a dosage of 16 kGy to obtain an ultra-high molecular weight polyethylene composition.

[0139] 3) The ultra-high molecular weight polyethylene composition was processed into a pipe in the same manner as in Comparative Example 5-1.

[0140] Comparative Example 6-1

[0141] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of Example 6, except that the composite antioxidant is added when the premixed composition is prepared in step 1. The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0142] 1) 100 parts by weight of ultra-high molecular weight polyethylene resin (viscosity average molecular weight 4.6 million, apparent density 0.44 g / cm 3 , average particle size 230 microns), 0.04 weight parts of GW-944 and 0.55 weight parts of composite antioxidant (the mass ratio of antioxidant 330 to thiodipropionate is 3:1) are mixed uniformly to form a premixed composition;

[0143] 2) irradiating the premixed composition with a cobalt source at a dose of 35 kGy to obtain a pre-irradiated composition; adding 0.10 parts by weight of diisopropylbenzene peroxide to the pre-irradiated composition in a splashing manner to obtain an ultra-high molecular weight polyethylene composition.

[0144] 3) The ultra-high molecular weight polyethylene composition is processed into a wear-resistant plate in the same manner as in Example 6.

[0145] Comparative Example 6-2

[0146] The preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is similar to that of comparative example 6-1, except that dicumyl peroxide is not added in step 2). The specific preparation method of the ultra-high molecular weight polyethylene composition provided in this comparative example is as follows:

[0147] 1) The preparation of the premixed composition is the same as that of Comparative Example 6-1;

[0148] 2) The premixed composition is irradiated with a cobalt source at a dose of 35 kGy to obtain an ultra-high molecular weight polyethylene composition.

[0149] 3) The ultra-high molecular weight polyethylene composition was processed into a wear-resistant plate in the same manner as in Comparative Example 6-1.

[0150] The pipes or plates prepared in the above-mentioned embodiments and comparative examples were subjected to corresponding tests, and the specific test results are shown in the following table.

[0151] Table 1

[0152]

[0153]

[0154] From the data comparison of each embodiment and comparative example in the above table, it can be seen that the ultra-high molecular weight polyethylene composition obtained according to the technical solution of the present invention can be processed into pipes and plates using existing pipe and plate production equipment, and a trace amount of crosslinking occurs during the molding process, so that the product has a low wear rate (less than or equal to 0.6%), a high load deformation temperature (greater than 80°C), and the color does not turn yellow after long-term storage. If no irradiation (Comparative Example 1) or the irradiation dose is not within the scope of the present invention (Comparative Example 2, Comparative Example 3-1), or the composition lacks necessary components (Comparative Example 4-1, Comparative Example 5-1), or the composition preparation steps are different (Comparative Example 6-1), or no peroxide is added (Comparative Example 3-2, Comparative Example 4-2, Comparative Example 5-2, Comparative Example 6-2), the obtained composition cannot meet the modification requirements for ultra-high molecular weight, and the yellow index of the obtained product increases significantly after being placed for a period of time, the product wear rate is high, and the load deformation temperature is low.

[0155] Moreover, the viscosity average molecular weight of the pre-irradiated composition in each embodiment of the above table is not significantly changed compared with the viscosity average molecular weight of the ultra-high molecular weight polyethylene resin used. It can be seen from this that the preparation method of the ultra-high molecular weight polyethylene composition provided by the present invention, by selecting appropriate additives (hindered amine stabilizer, antioxidant and peroxide) and their addition amounts, under a suitable irradiation dose, the ultra-high molecular weight polyethylene resin in the pre-irradiated composition obtained by the combined action of the ultra-high molecular weight polyethylene resin, part of the antioxidant and the hindered amine stabilizer does not undergo cross-linking, but is more likely to undergo micro-cross-linking under the action of peroxide, and if the irradiation dose is too large, or the composition lacks necessary components (Comparative Example 3-1, Comparative Example 4-1, Comparative Example 5-1), the ultra-high molecular weight polyethylene resin will undergo certain cross-linking after irradiation: the viscosity average molecular weight of the pre-irradiated composition is increased by more than 10% compared with the ultra-high molecular weight polyethylene used.

[0156] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, technicians familiar with the field may make various corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should all fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing an ultra-high molecular weight polyethylene composition, characterized in that: The steps include: 1) uniformly mixing an ultra-high molecular weight polyethylene resin, a hindered amine stabilizer, and a portion of an antioxidant to obtain a premixed composition; 2) After the premixed composition is irradiated with a high-energy electron beam or a cobalt source at 15 to 50 Kgy, the remaining antioxidant and peroxide are added to obtain the ultra-high molecular weight polyethylene composition.

2. The ultra-high molecular weight polyethylene composition according to claim 1, characterized in that The irradiation dose is 20-40 KGy.

3. The preparation method according to claim 1, characterized in that: The mass ratio of the antioxidant in step 1) to the antioxidant in step 2) is 1:0.35-4; preferably 1:1-2.

5.

4. The preparation method according to claim 1, characterized in that: Based on 100 parts by weight of the ultra-high molecular weight polyethylene resin, the hindered amine stabilizer is 0.01 to 0.05 parts by weight, the antioxidant is 0.4 to 0.8 parts by weight, and the peroxide is 0.03 to 0.2 parts by weight.

5. The preparation method according to claim 1, characterized in that: The ultra-high molecular weight polyethylene resin has a viscosity average molecular weight of 1.5 to 5 million and an apparent density of 0.35 to 0.50 g / cm 3 , the average particle size is 70 to 300 microns.

6. The preparation method according to claim 1, characterized in that: The hindered amine stabilizer is selected from bis(2,2,6,6,-tetramethyl-4-piperidinyl) sebacate, bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate, 2,2,6,6-tetramethyl-4-piperidinyl stearate, poly{(6-morpholinyl-5-triazine-2,4-diyl)(2,2,6,6-tetramethylpiperidinyl)iminohexamethylene[(2,2,6,6-tetramethylpiperidinyl)-imino]}, poly{[6-[(1,1,3,3-tetramethylbutyl)amino]]-1,3,5-triazine-2,4-[(2,2,6,6,-tetramethyl-piperidinyl)imino]-1,6-hexanediyl[(2,2,6 Any one of the following: a polymer of the reaction product of N,N'-bis(2,2,6,6-tetramethyl-4-piperidinyl)-1,6-hexanediamine and 2,4,6-trichloro-1,3,5-triazine, N-butyl-1-butylamine and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine, and a polymeric hindered amine stabilizer containing a structural unit of 2,2,6,6-tetramethylpiperidinol-4-methacrylate and / or 1,2,2,6,6-pentamethylpiperidinol-4-methacrylate.

7. The preparation method according to claim 1, characterized in that: The antioxidant includes a primary antioxidant, and the primary antioxidant is a phenolic antioxidant; preferably, the phenolic antioxidant is selected from at least one of 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid n-octadecyl alcohol ester, 4,4'-thiobis(6-tert-butyl-3-methylphenol) and tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol.

8. The preparation method according to claim 7, characterized in that: The antioxidant further comprises a secondary antioxidant, and the secondary antioxidant is selected from any one of phosphite antioxidants, hydrazide antioxidants and thioester antioxidants; preferably, the mass ratio of the primary antioxidant to the secondary antioxidant is 2 to 4:

1.

9. The preparation method according to claim 1, characterized in that: The peroxide is selected from at least one of tert-butyl peroxyisopropyl carbonate, tert-butyl peroxylaurate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, tert-butyl peroxyacetate, di-tert-butyl diperoxyphthalate, tert-butyl peroxymaleic acid, cyclohexanone peroxide, tert-butyl peroxybenzoate, diisopropyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl peroxide isopropyl peroxide, tert-butyl hydroperoxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butyl-peroxy)hexane-3 and α,α'-bis-tert-butylperoxy-1,4-diisopropylbenzene.

10. The preparation method according to claim 1, characterized in that: The peroxide is added by spraying, dipping or splashing.

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