Blending material containing high-crosslinking recycled material and preparation method thereof

Abstract

The invention discloses a blending material containing high-crosslinking recycled materials and a preparation method thereof, and belongs to the technical field of polymer foaming materials, the blending material is prepared by mixing polyolefin recycled materials, polystyrene, modified fibers and other raw materials, the preparation process comprises mixing, extrusion, injection molding and cooling molding, and various additives are involved to enhance the performance of the material. Compared with the prior art, the material disclosed by the invention has the advantages that the bending property and the dimensional stability of a blended material are remarkably improved, the recoverability is realized, the upgrading of the domestic packaging material industry is promoted, the high requirement of precise electronic protection of photoelectric products is met, and meanwhile, the environment-friendly and sustainable development trend is responded.

Description

Technical Field

[0001] The invention relates to the technical field of polymer foaming materials, in particular to a blended material containing highly cross-linked recycled materials and a preparation method thereof. Background Art

[0002] With the rapid development of global science and technology, the optoelectronic industry has become an important part of the high-tech industry, and its products are widely used in communications, medical, military, aerospace and other fields. In this context, the precision and fragility of optoelectronic products have put forward higher requirements for packaging materials. These packaging materials must not only have excellent protective properties, but also ensure the safety of products during transportation and storage.

[0003] At present, plastic foam packaging materials are in huge demand in industries such as machinery, electronics and electrical appliances, and biomedicine due to their light weight and good protective properties, accounting for about a quarter of the world's total plastic consumption.

[0005] The performance of traditional domestic plastic packaging materials cannot meet the needs of high-demand industries such as optoelectronic products, which has made the domestic market rely on imported EPO materials for a long time. This dependence not only increases costs, but also restricts the development of domestic industries. Therefore, the research and development of high-performance packaging materials with independent intellectual property rights and recyclability has become an urgent need for the domestic industry.

[0006] Chinese invention patent CN115850783A discloses a low-density toughened polypropylene foam material composition and a low-density toughened polypropylene foam material and a preparation method thereof. The composition comprises polypropylene, polystyrene and an elastomer, and based on 100 parts by weight of the polypropylene, the polystyrene is 5 to 15 parts by weight, and the elastomer is 5 to 25 parts by weight; wherein the polypropylene is a random copolymer polypropylene obtained by copolymerizing C2-C4 olefins and propylene, and the content of C2-C4 olefins is 1 to 8% by weight. In addition, the preparation method is simple, has low production cost and is suitable for large-scale production, and can prepare a low-density foamed polypropylene material with uniform pores and excellent mechanical properties. However, the product prepared by the method still has room for improvement in bending performance and dimensional change rate. Summary of the invention

[0007] In order to solve the deficiencies in the prior art, the present invention aims to provide a blended material containing highly cross-linked recycled material and a preparation method thereof.

[0008] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0009] A method for preparing a blended material containing highly cross-linked recycled material is as follows, in parts by weight:

[0010] 250-350 parts of polyolefin recycled materials, 500-700 parts of polystyrene, 15-25 parts of modified fibers, 8-12 parts of polyethylene resin, 1-3 parts of dispersant, 4-6 parts of lubricant, 0.4-0.6 parts of antistatic agent, 8-12 parts of white carbon black, 2-4 parts of vulcanizing agent, 1-3 parts of vulcanization accelerator, and 5-7 parts of toughening agent are mixed for 10-20 minutes at a mixing temperature of 155-165°C. The polyolefin recycled materials are PP recycled materials and PS recycled materials. and PE recycled material in a weight ratio of 0.5~2:2~4:1~3; after mixing, put into extrusion equipment, melt-formed and then extruded, the temperature of the feeding section and compression section of the extruder is 145~155°C, the temperature of the homogenizing section is 165~175°C, and the temperature of the die is 135~145°C to obtain a semi-finished product; then 3~5 parts of foaming agent are added, the particles are put into an injection molding machine and heated to 200~220°C, and finally injected into a mold and formed after cooling to obtain a blended material.

[0011] The vulcanizing agent is at least one of sulfur, di-tert-butyl peroxide isopropylbenzene, di-tert-butyl peroxide and diisopropylbenzene peroxide.

[0012] The vulcanization accelerator is at least one of N-tert-butyl-2-benzothiazole sulfenamide and tetramethylthiuram disulfide.

[0013] The foaming agent is at least one of azodicarbonamide, sodium bicarbonate, petroleum ether and p-toluenesulfonyl semicarbazide.

[0014] The antistatic agent is a nonionic surfactant.

[0015] The dispersant is at least one of sodium dodecylbenzene sulfonate, polyethyleneimine, sodium stearate and polyvinyl alcohol.

[0016] The lubricant is at least one of vinyl bisstearamide, polysiloxane, calcium stearate, magnesium stearate, and zinc stearate.

[0017] The toughening agent is styrene-butadiene block copolymer.

[0018] The preparation method of the modified fiber is as follows, in parts by weight:

[0019] S1. In 500-700 parts of dimethyl sulfoxide, 8-12 parts of 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane, 4-8 parts of oxytetracycline hydrochloride and 1-3 parts of dimethylethanolamine are added, and the mixture is continuously stirred for 8-12 hours at 80-100° C., and then the dimethyl sulfoxide is removed by reduced pressure distillation, and the obtained polymer is added to 800-1200 parts of ether to precipitate, and the pretreated product is obtained after filtering and drying;

[0020] S2. Add 4 to 6 parts of the pretreated material prepared in step S1 and 0.1 to 0.3 parts of dibenzoyl peroxide to 400 to 600 parts of water, and stir until completely dissolved. Add 40 to 60 parts of aramid staple fibers to the above solution and treat at 70 to 90° C. for 3 to 5 hours. Then remove unreacted raw materials and by-products by filtering, wash the fibers with water and acetone for 1 to 3 times, and dry to obtain modified fibers.

[0021] The effects of each substance of the present invention are as follows:

[0022] As one of the main raw materials, polyolefin recycled materials (including PP recycled materials, PS recycled materials and PE recycled materials) provide the basic structure and physical properties of the material while realizing the recyclability of the material.

[0023] Polystyrene (PS) is one of the main raw materials. It provides rigidity and strength, while forming a blending system with rubber and recycled materials to enhance the overall performance of the material.

[0024] The modified fibers introduce active groups through specific chemical reactions, and the modified fibers enhance the mechanical properties of the blended materials, especially the bending properties and dimensional stability.

[0025] Polyethylene resin As a processing aid, polyethylene resin may be used to improve the processing properties of materials and increase the flexibility of materials.

[0026] Dispersants such as sodium dodecylbenzene sulfonate are used to improve the dispersibility of the raw materials during the mixing process and ensure the uniformity of the blended materials.

[0027] Lubricants are used to reduce friction between materials and improve fluidity during processing.

[0028] Antistatic agents such as nonionic surfactants are used to reduce static electricity accumulation in materials during processing and use.

[0029] As a filler, white carbon black can improve the strength and wear resistance of materials.

[0030] Vulcanizing agents are used to promote the vulcanization reaction of rubber and improve the crosslinking degree and stability of the material.

[0031] Vulcanization accelerators are used to speed up the vulcanization reaction and improve the vulcanization efficiency.

[0032] Toughening agents such as styrene-butadiene-styrene block copolymers are used to improve the toughness and impact resistance of materials.

[0033] Foaming agents are used to generate bubbles during the material molding process to form a foamed structure and improve the lightweight and thermal insulation properties of the material.

[0034] Dimethyl sulfoxide is used as a solvent to dissolve 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane, oxytetracycline hydrochloride and dimethylethanolamine for subsequent chemical reactions.

[0035] 2,2-Bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane is used as the main modifier to undergo a ring-opening reaction with oxytetracycline hydrochloride to generate a pretreated product containing imino and hydroxyl groups, which can undergo a grafting reaction with aramid staple fibers.

[0036] Oxytetracycline hydrochloride, as a compound containing multiple active groups, undergoes a ring-opening reaction with 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane to generate a pretreatment product.

[0037] Dimethylethanolamine, as a cosolvent or catalyst, may be used to promote the ring-opening reaction.

[0038] Ether is used as a non-polar solvent to precipitate the polymer obtained through the ring-opening reaction. After removing dimethyl sulfoxide by vacuum distillation, the polymer is precipitated in ether.

[0039] Dibenzoyl peroxide, as a free radical initiator, initiates a grafting reaction during the preparation of the modified fiber, so that the pretreated material can undergo a grafting reaction on the surface of the aramid staple fiber.

[0040] Aramid staple fibers are used as a substrate and are grafted with the pretreated material to obtain modified fibers, thereby enhancing the mechanical properties of the blended material, especially the bending properties and dimensional stability.

[0041] Water is used as a solvent to dissolve the pre-treated material and dibenzoyl peroxide to form a solution for treating aramid staple fibers.

[0042] The combination and interaction of these substances make the blended material of the present invention have good physical properties, processing properties and environmental protection performance, and is suitable for precision electronic protective packaging in high-demand industries such as optoelectronic products.

[0043] Compared with the prior art, it has the following beneficial effects:

[0044] 1) The present invention successfully prepares a blended material containing highly cross-linked recycled materials through specific chemical modification and blending processes, which significantly improves the bending performance and dimensional stability of the material, making it more suitable for the precision electronic protective packaging needs of high-demand industries such as optoelectronic products.

[0045] 2) The blended material developed by the present invention not only has excellent performance, but is also recyclable, which is in line with the current global trend of green environmental protection and sustainable development. This material helps reduce environmental pollution and reduces dependence on traditional disposable plastic packaging materials.

[0046] 3) The present invention helps to break the dependence on imported EPO materials, reduce the cost of optoelectronic product packaging, reduce supply chain risks, and improve the competitiveness of the domestic industry by achieving localization and recycling of materials. DETAILED DESCRIPTION

[0047] Main sources of substances:

[0048] PP recycled material, item number: PP, color: black, Dongguan Yizhan Plastic Products Co., Ltd.

[0049] PS recycled material, product name: GPPS, grade: Level 1, Yuyao Laihua Plastic Co., Ltd.

[0050] PE recycled material, item number LLDPE-001, grade: Grade 1, Foshan Yaotaiyuan Plastic Industry Co., Ltd.

[0051] Polystyrene, item number: 158K, manufacturer: BASF-YPC.

[0052] Polyethylene resin, brand: 5000S, Shandong Yousuo Chemical Technology Co., Ltd.

[0053] Styrene-butadiene block copolymer, product number: SBS, brand: YH-1401, manufacturer: Sinopec Baling.

[0054] Non-ionic surfactant, model: 129MB, ATMER 129, chemical name: glyceryl monostearyl ester (monoester content not less than 90%), brand: Hoda.

[0055] Aramid staple fiber, length: 6mm, item number: SWT-0102, Dongguan Sovit Special Wire and Tape Co., Ltd.

[0056] Polyethylene glycol monomethyl ether glycidyl ether, model: PZ658465846, Xuzhou Pei Ze New Materials Co., Ltd.

[0057] The remaining raw materials in the examples and comparative examples of the present invention are all commercially available products.

[0058] The design idea of ​​this invention is to develop a domestically produced, recyclable, high-performance ERPO (recyclable expanded polystyrene / rubber copolymer) material to replace imported EPO materials. By improving the physical properties and chemical stability of the material, it can meet the packaging needs of precision electronic protection in high-demand industries such as optoelectronic products. At the same time, it responds to the trend of environmental protection and sustainable development, reduces costs, reduces supply chain risks, and promotes the upgrading and development of the domestic packaging materials industry.

[0059] Example 1

[0060] A method for preparing a blended material containing highly cross-linked recycled material is as follows:

[0061] 300g of polyolefin recycled material, 600g of polystyrene, 20g of modified fiber, 10g of polyethylene resin, 2g of sodium dodecylbenzene sulfonate, 5g of zinc stearate, 0.5g of nonionic surfactant, 10g of white carbon black, 3g of sulfur, 2g of N-tert-butyl-2-benzothiazole sulfonamide, and 6g of styrene-butadiene block copolymer are mixed for 15 minutes at a mixing temperature of 160°C, wherein the polyolefin recycled material is a mixture of PP recycled material, PS recycled material and PE recycled material in a weight ratio of 1:3:2; after mixing, the mixed material is put into an extrusion device, melt-molded and extruded, the temperature of the feeding section and compression section of the extruder is 150°C, the temperature of the homogenizing section is 170°C, and the temperature of the die is 140°C to obtain a semi-finished product; 4g of azodicarbonamide is added, the particles are put into an injection molding machine and heated to 210°C, and finally injected into a mold and molded after cooling to obtain a blended material.

[0062] The preparation method of the modified fiber is as follows:

[0063] S1. In 600 g of dimethyl sulfoxide, 10 g of 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane, 6 g of oxytetracycline hydrochloride and 2 g of dimethylethanolamine are added, and the mixture is stirred for 10 hours at 90° C., and then the dimethyl sulfoxide is removed by vacuum distillation, and the obtained polymer is added to 1000 g of ether to precipitate, and the polymer is filtered and dried to obtain a pretreated product;

[0064] S2. Add 5 g of the pretreated material prepared in step S1 and 0.2 g of dibenzoyl peroxide into 500 g of water and stir until completely dissolved. Add 50 g of aramid staple fiber to the above solution and treat at 80°C for 4 hours. Then remove unreacted raw materials and by-products by filtration. Wash the fiber three times with water and acetone and dry it to obtain modified fiber.

[0065] Example 2

[0066] The preparation method of a blended material containing highly cross-linked recycled materials is basically the same as that of Example 1, the only difference being that the preparation method of the modified fiber is different.

[0067] The preparation method of the modified fiber is as follows:

[0068] S1. In 600 g of dimethyl sulfoxide, 10 g of glyceryl propoxy triglycidyl ether, 6 g of oxytetracycline hydrochloride and 2 g of dimethylethanolamine are added, and the mixture is continuously stirred at 90° C. for 10 hours, and then the dimethyl sulfoxide is removed by vacuum distillation, and the obtained polymer is added to 1000 g of ether to precipitate, and the polymer is filtered and dried to obtain a pretreated product;

[0069] S2. Add 5 g of the pretreated material prepared in step S1 and 0.2 g of dibenzoyl peroxide into 500 g of water and stir until completely dissolved. Add 50 g of aramid staple fiber to the above solution and treat at 80°C for 4 hours. Then remove unreacted raw materials and by-products by filtration. Wash the fiber three times with water and acetone and dry it to obtain modified fiber.

[0070] Example 3

[0071] The preparation method of a blended material containing highly cross-linked recycled materials is basically the same as that of Example 1, the only difference being that the preparation method of the modified fiber is different.

[0072] The preparation method of the modified fiber is as follows:

[0073] S1. In 600 g of dimethyl sulfoxide, 10 g of tetraethylene glycol diglycidyl ether, 6 g of oxytetracycline hydrochloride and 2 g of dimethylethanolamine were added, and the mixture was stirred for 10 hours at 90° C., and then the dimethyl sulfoxide was removed by vacuum distillation. The obtained polymer was added to 1000 g of ether to precipitate, and the polymer was filtered and dried to obtain a pretreated product.

[0074] S2. Add 5 g of the pretreated material prepared in step S1 and 0.2 g of dibenzoyl peroxide into 500 g of water and stir until completely dissolved. Add 50 g of aramid staple fiber to the above solution and treat at 80°C for 4 hours. Then remove unreacted raw materials and by-products by filtration. Wash the fiber three times with water and acetone and dry it to obtain modified fiber.

[0075] Example 4

[0076] The preparation method of a blended material containing highly cross-linked recycled materials is basically the same as that of Example 1, the only difference being that the preparation method of the modified fiber is different.

[0077] The preparation method of the modified fiber is as follows:

[0078] S1. In 600 g of dimethyl sulfoxide, 10 g of 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane, 6 g of methacryloyl hydrazide and 2 g of dimethylethanolamine were added, and the mixture was stirred for 10 hours at 90° C., and then the dimethyl sulfoxide was removed by vacuum distillation. The obtained polymer was added to 1000 g of ether to precipitate, and the polymer was filtered and dried to obtain a pretreated product.

[0079] S2. Add 5 g of the pretreated material prepared in step S1 and 0.2 g of dibenzoyl peroxide into 500 g of water and stir until completely dissolved. Add 50 g of aramid staple fiber to the above solution and treat at 80°C for 4 hours. Then remove unreacted raw materials and by-products by filtration. Wash the fiber three times with water and acetone and dry it to obtain modified fiber.

[0080] Example 5

[0081] The preparation method of a blended material containing highly cross-linked recycled materials is basically the same as that of Example 1, the only difference being that the preparation method of the modified fiber is different.

[0082] The preparation method of the modified fiber is as follows:

[0083] S1. In 600 g of dimethyl sulfoxide, 10 g of 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane, 6 g of acrylamide and 2 g of dimethylethanolamine are added, and the mixture is stirred for 10 hours at 90° C., and then the dimethyl sulfoxide is removed by vacuum distillation, and the obtained polymer is added to 1000 g of ether to precipitate, and the polymer is filtered and dried to obtain a pretreated product;

[0084] S2. Add 5 g of the pretreated material prepared in step S1 and 0.2 g of dibenzoyl peroxide into 500 g of water and stir until completely dissolved. Add 50 g of aramid staple fiber to the above solution and treat at 80°C for 4 hours. Then remove unreacted raw materials and by-products by filtration. Wash the fiber three times with water and acetone and dry it to obtain modified fiber.

[0085] Comparative Example 1

[0086] The preparation method of a blended material containing highly cross-linked recycled materials is basically the same as that of Example 1, the only difference being that the preparation method of the modified fiber is different.

[0087] The preparation method of the modified fiber is as follows:

[0088] S1. In 600 g of dimethyl sulfoxide, 10 g of polyethylene glycol monomethyl ether glycidyl ether, 6 g of oxytetracycline hydrochloride and 2 g of dimethylethanolamine are added, and the mixture is continuously stirred at 90° C. for 10 hours, and then the dimethyl sulfoxide is removed by vacuum distillation, and the obtained polymer is added to 1000 g of ether to precipitate, and the polymer is filtered and dried to obtain a pretreated product;

[0089] S2. Add 5 g of the pretreated material prepared in step S1 and 0.2 g of dibenzoyl peroxide into 500 g of water and stir until completely dissolved. Add 50 g of aramid staple fiber to the above solution and treat at 80°C for 4 hours. Then remove unreacted raw materials and by-products by filtration. Wash the fiber three times with water and acetone and dry it to obtain modified fiber.

[0090] Comparative Example 2

[0091] The preparation method of a blended material containing highly cross-linked recycled materials is basically the same as that of Example 1, the only difference being that the preparation method of the modified fiber is different.

[0092] The preparation method of the modified fiber is as follows:

[0093] S1. In 600 g of dimethyl sulfoxide, 10 g of 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane, 6 g of N-(3-aminopropyl)methacrylamide hydrochloride and 2 g of dimethylethanolamine are added. The mixture is stirred for 10 hours at 90° C., and then the dimethyl sulfoxide is removed by vacuum distillation. The obtained polymer is added to 1000 g of ether to precipitate, and the polymer is filtered and dried to obtain a pretreated product.

[0094] S2. Add 5 g of the pretreated material prepared in step S1 and 0.2 g of dibenzoyl peroxide into 500 g of water and stir until completely dissolved. Add 50 g of aramid staple fiber to the above solution and treat at 80°C for 4 hours. Then remove unreacted raw materials and by-products by filtration. Wash the fiber three times with water and acetone and dry it to obtain modified fiber.

[0095] Comparative Example 3

[0096] A method for preparing a blended material containing highly cross-linked recycled material is as follows:

[0097] 300g of polyolefin recycled material, 600g of polystyrene, 20g of aramid staple fiber, 10g of polyethylene resin, 2g of sodium dodecylbenzene sulfonate, 5g of zinc stearate, 0.5g of nonionic surfactant, 10g of white carbon black, 3g of sulfur, 2g of N-tert-butyl-2-benzothiazole sulfonamide, and 6g of styrene-butadiene-styrene block copolymer were mixed for 15min at a banburying temperature of 160°C, and then put into an extrusion device after mixing, and extruded after melt molding. The temperature of the feeding section and compression section of the extruder was 150°C, the temperature of the homogenizing section was 170°C, and the temperature of the die was 140°C to obtain a semi-finished product; 4g of azodicarbonamide was added, the particles were put into an injection molding machine and heated to 210°C, and finally injected into a mold and molded after cooling to obtain a blended material.

[0098] Comparative Example 4

[0099] A method for preparing a blended material containing highly cross-linked recycled material is as follows:

[0100] 300g of polyolefin recycled material, 600g of polystyrene, 10g of polyethylene resin, 2g of sodium dodecylbenzene sulfonate, 5g of zinc stearate, 0.5g of nonionic surfactant, 10g of white carbon black, 3g of sulfur, 2g of N-tert-butyl-2-benzothiazole sulfonamide, and 6g of styrene-butadiene-styrene block copolymer were mixed for 15min at a banburying temperature of 160°C, and then put into an extrusion device after mixing, and extruded after melt molding. The temperature of the feeding section and compression section of the extruder was 150°C, the temperature of the homogenizing section was 170°C, and the temperature of the die was 140°C to obtain a semi-finished product; 4g of azodicarbonamide was added, the particles were put into an injection molding machine and heated to 210°C, and finally injected into a mold and molded after cooling to obtain a blended material.

[0101] Test Example 1

[0102] Bending performance test

[0103] The blended materials prepared in the examples and control examples were tested with reference to the test method in GB / T 8812.1-2007 "Determination of flexural properties of rigid foam plastics Part 1: Basic flexural test". The state adjustment and test were carried out under the conditions of relative humidity of 50% and temperature of 23°C. The sample size was: 350mm×100mm×25mm. The test speed was 20mm / min. The flexural strength was tested. Five groups were tested in each case and the average value was taken. The specific test data are shown in Table 1.

[0104] Table 1

[0105] Experimental protocol Bending strength / kPa Example 1 602 Example 2 585 Example 3 573 Example 4 589 Example 5 583 Comparative Example 1 553 Comparative Example 2 580 Comparative Example 3 528 Comparative Example 4 481

[0106] Test Example 2

[0107] Dimensional change rate test

[0108] The test method refers to GB / T 8811-2008 "Test method for dimensional stability of rigid foam plastics" to test the blended materials prepared in the examples and the control examples. The sample size is: 100mm×100mm×25mm. The state is adjusted under the conditions of relative humidity of 50% and temperature of 23°C. The test is carried out under the conditions of relative humidity of 50% and temperature of 70°C. The total time is 48h. The arithmetic mean of the dimensional change rate of length, width and thickness is the sample dimensional change rate. The average value is taken for each test of 3 groups. The test results are shown in Table 2.

[0109] Table 2

[0110] Experimental protocol Dimensional change rate / % Example 1 0.16 Example 2 0.21 Example 3 0.24 Example 4 0.17 Example 5 0.18 Comparative Example 1 0.28 Comparative Example 2 0.19 Comparative Example 3 0.31 Comparative Example 4 0.53

[0111] It can be seen from the data of test examples 1 and 2 that the bending performance and dimensional change rate of the blended material prepared in Example 1 are the best.

[0112] The present invention utilizes 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane and oxytetracycline hydrochloride to undergo a ring-opening reaction to obtain a pretreated product; under the action of dibenzoyl peroxide, the pretreated product undergoes a grafting reaction on the surface of aramid staple fibers to obtain modified fibers, wherein the pretreated product contains imino and hydroxyl groups, and the pretreated product is grafted onto the surface of the aramid staple fibers, thereby introducing imino and hydroxyl active groups onto the fiber surface.

[0113] The flexible chain segments of the grafted pretreated material of the aramid staple fiber have a good toughening effect on the blended material. At the same time, the aramid staple fiber itself also has good mechanical properties such as bending performance and dimensional change rate. The grafted pretreated chain segments can improve the dispersion of the fiber in highly cross-linked recycled materials, thereby making the aramid staple fiber play a better role and significantly improving the bending performance and dimensional change rate of the blended material.

[0114] The 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane used in Example 1 exhibits excellent bending properties and dimensional stability due to its unique molecular structure. The molecule contains two glycidyloxy groups, which can undergo a ring-opening reaction with oxytetracycline hydrochloride to obtain a pretreated product, which contains an alkenyl group and a benzene ring. Under the action of dibenzoyl peroxide, a grafting reaction occurs on the surface of aramid staple fibers to obtain modified fibers, thereby enhancing the interfacial bonding between the modified fibers and the blended material. In addition, the butoxypropoxy side chain in the molecule not only provides additional flexibility, but also increases the steric hindrance of the molecule, which helps to disperse the fibers in the blended material, thereby improving the overall performance of the material. This structural design enables the modified fiber to play a better toughening role in the blended material. Compared with glycerol propoxy triglycidyl ether, tetraethylene glycol diglycidyl ether and polyethylene glycol monomethyl ether glycidyl ether used in other embodiments and comparative examples, the latter have a simpler molecular structure and a shorter side chain, and cannot provide the same steric hindrance and flexibility, so the effect of improving the performance of the blended material is not as good as that of Example 1. Therefore, these characteristics of 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane give it a significant advantage in improving the bending properties and dimensional stability of the blended material.

[0115] The oxytetracycline hydrochloride used in Example 1, as a compound having multiple active groups, undergoes a ring-opening reaction with 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane, and the resulting pretreated material contains alkenyl groups, which can undergo a grafting reaction with aramid staple fibers under the initiation of dibenzoyl peroxide. The molecular structure of oxytetracycline hydrochloride contains multiple cyclic structures and active functional groups, which may enhance the interaction with aramid staple fibers, improve the grafting efficiency and the dispersibility of the modified fibers, and thus provide a better toughening effect in the blended material. In contrast, although the methacryloyl hydrazide in Example 4, the acrylamide in Example 5, and the N-(3-aminopropyl)methacrylamide hydrochloride in Comparative Example 2 also contain active groups, their molecular structures are relatively simple and may not provide the same spatial structure and functional group diversity as oxytetracycline hydrochloride. This may lead to their lower efficiency in the grafting reaction with aramid staple fibers or their poorer dispersibility in the blends than oxytetracycline hydrochloride-modified fibers, thus affecting the flexural properties and dimensional change rate of the blends.

Claims

1. A method for preparing a blended material containing highly cross-linked recycled materials, characterized in that: The method is as follows, in parts by weight: 250-350 parts of polyolefin recycled materials, 500-700 parts of polystyrene, 15-25 parts of modified fibers, 8-12 parts of polyethylene resin, 1-3 parts of dispersant, 4-6 parts of lubricant, 0.4-0.6 parts of antistatic agent, 8-12 parts of white carbon black, 2-4 parts of vulcanizing agent, 1-3 parts of vulcanization accelerator, and 5-7 parts of toughening agent are mixed for 10-20 minutes at a mixing temperature of 155-165°C. The polyolefin recycled materials are PP recycled materials and PS recycled materials. and PE recycled material in a weight ratio of 0.5~2:2~4:1~3; after mixing, put into extrusion equipment, melt-formed and then extruded, the temperature of the feeding section and compression section of the extruder is 145~155°C, the temperature of the homogenizing section is 165~175°C, and the temperature of the die is 135~145°C to obtain a semi-finished product; then 3~5 parts of foaming agent are added, the particles are put into an injection molding machine and heated to 200~220°C, and finally injected into a mold and formed after cooling to obtain a blended material.

2. The method for preparing a blended material containing highly cross-linked recycled materials according to claim 1, characterized in that: The vulcanizing agent is at least one of sulfur, di-tert-butyl peroxide isopropylbenzene, di-tert-butyl peroxide and diisopropylbenzene peroxide.

3. The method for preparing a blended material containing highly cross-linked recycled materials according to claim 1, characterized in that: The vulcanization accelerator is at least one of N-tert-butyl-2-benzothiazole sulfenamide and tetramethylthiuram disulfide.

4. The method for preparing a blended material containing highly cross-linked recycled materials according to claim 1, characterized in that: The foaming agent is at least one of azodicarbonamide, sodium bicarbonate, petroleum ether and p-toluenesulfonyl semicarbazide.

5. The method for preparing a blended material containing highly cross-linked recycled materials according to claim 1, characterized in that: The antistatic agent is a nonionic surfactant.

6. The method for preparing a blended material containing highly cross-linked recycled materials according to claim 1, characterized in that: The dispersant is at least one of sodium dodecylbenzene sulfonate, polyethyleneimine, sodium stearate and polyvinyl alcohol.

7. The method for preparing a blended material containing highly cross-linked recycled materials according to claim 1, characterized in that: The lubricant is at least one of vinyl bisstearamide, polysiloxane, calcium stearate, magnesium stearate, and zinc stearate.

8. The method for preparing a blended material containing highly cross-linked recycled materials according to claim 1, characterized in that: The toughening agent is styrene-butadiene block copolymer.

9. The method for preparing a blended material containing highly cross-linked recycled materials according to claim 1, characterized in that: The preparation method of the modified fiber is as follows, in parts by weight: S1. In 500-700 parts of dimethyl sulfoxide, 8-12 parts of 2,2-bis[p-(2-glycidyloxy-3-butoxypropoxy)phenyl]propane, 4-8 parts of oxytetracycline hydrochloride and 1-3 parts of dimethylethanolamine are added, and the mixture is continuously stirred for 8-12 hours at 80-100° C., and then the dimethyl sulfoxide is removed by reduced pressure distillation, and the obtained polymer is added to 800-1200 parts of ether to precipitate, and the pretreated product is obtained after filtering and drying; S2. Add 4 to 6 parts of the pretreated material prepared in step S1 and 0.1 to 0.3 parts of dibenzoyl peroxide to 400 to 600 parts of water, and stir until completely dissolved. Add 40 to 60 parts of aramid staple fibers to the above solution and treat at 70 to 90° C. for 3 to 5 hours. Then remove unreacted raw materials and by-products by filtering, wash the fibers with water and acetone for 1 to 3 times, and dry to obtain modified fibers.

10. A blended material containing highly cross-linked recycled materials, characterized in that: The method is prepared by the preparation method according to any one of claims 1 to 9.