Recycling method of modified plastic for automobiles

Abstract

The invention provides a recycling method of modified plastic for an automobile. The recycling method comprises the following steps: S1, crushing, cleaning, removing impurities, drying and the like of waste modified plastic PP for the automobile; s2, plasma treatment is adopted, and pretreated waste modified plastic particles for automobiles are obtained; s3, putting the waste modified plastic particles for the automobile, inorganic matter lithium salt, branched polysilanol, the modified attapulgite and the polyurethane urea elastomer into a reaction kettle, and stirring and mixing; adding a dispersing agent and an antioxidant into the mixture, and mixing; and plasticizing, extruding, cooling and granulating to obtain the regenerated plastic particles. Through the method, the mechanical properties and the like of the regenerated material can be remarkably improved, application requirements can be met only by adding part of raw materials during application, and the recycling efficiency and quality of the regenerated material are greatly improved.

Description

Technical Field

[0001] The invention belongs to the field of plastic recycling, and specifically relates to a recycling method for modified plastics for automobiles. Background Art

[0002] Automotive plastics are widely used in automobile manufacturing due to their advantages such as lightweight, design flexibility, corrosion resistance and cost-effectiveness. These plastics are not only used for interior parts (such as dashboards, door panels, seats, etc.), but also for exterior parts (such as bumpers, grilles, headlight covers, etc.), as well as functional parts (such as air intake systems, fuel systems, etc.). Common automotive plastics include polypropylene, polycarbonate, polyethylene, ABS, polyurethane, polyamide, polyoxymethylene, polyethylene terephthalate, etc.

[0003] The recycling of waste plastics has attracted people's attention. Effectively realizing the recycling and reuse of waste plastics can not only protect the ecological environment, but also reduce the production costs of enterprises. The recycling of waste plastics is based on waste plastics, which are modified and reused through classification, cleaning, crushing, blending, melting, granulation and other processes. Commonly used methods include filling modification and blending modification. Among them, filling modification is to add a certain amount of inorganic or organic fillers to waste plastics to improve certain properties of the products, such as rigidity and hardness; while blending modification is to blend waste plastics with other plastics and substances to improve their mechanical properties.

[0004] In the existing recycling of waste modified plastics for automobiles, there are problems such as uneven modification and blending, and the inability to achieve both toughness and strength. When put into use, a large amount of raw materials still needs to be added, and the recycling efficiency and effectiveness are not obvious. Summary of the invention

[0005] The purpose of the present invention is to provide a method for recycling modified plastic PP for automobiles, by pre-treating waste modified plastic PP to improve surface properties, and adding a variety of effective ingredients in the blending, significantly improving the mechanical properties and other properties of the recycled material, and only needing to add part of the raw materials to meet the application requirements during application, thereby greatly improving its recycling efficiency and quality.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A method for recycling modified plastic PP for automobiles comprises the following steps:

[0008] S1: Crushing, cleaning, removing impurities and drying of waste modified plastic PP for automobiles;

[0009] S2: using plasma treatment to obtain pre-treated automobile waste modified plastic PP particles;

[0010] S3: 80-100 parts by weight of the waste modified plastic PP particles for automobiles prepared in step S2, 5-10 parts of inorganic lithium salt, 10-15 parts of branched polysilanol, 3-7 parts of modified attapulgite and 10-20 parts of polyurethane urea elastomer are placed in a reaction kettle and stirred and mixed; a dispersant and an antioxidant are then added thereto and mixed;

[0011] S4: After plasticizing, extruding, cooling and granulating, the recycled plastic particles are obtained.

[0012] Furthermore, in step S1, the particles are crushed to 1-3 cm; the particles are washed to remove the silt and oil; the impurities are removed by four-stage flotation; and the particles are dried at 80° C. for 1 hour.

[0013] Furthermore, the plasma treatment process in step S2 is: placing the dried automobile waste modified plastic particles in a plasma reaction device, purging with helium at room temperature, and plasma treatment for 1-3 hours at a discharge power of 10-30W and a carrier gas flow rate of 45-65mL / min.

[0014] Furthermore, the plasma reaction device is a double-layer dielectric flat plate structure dielectric barrier discharge plasma reactor, and the materials of the solid dielectric spheres are zirconia ceramic and barium titanate ceramic respectively.

[0015] Furthermore, the inorganic lithium salt in step S3 is one or a mixture of lithium nitrate or lithium sulfate.

[0016] Furthermore, the preparation process of the branched polysilicone is as follows: take 15-25 parts of polycaprolactone triol, 9-13 parts of (3-glycidyloxypropyl) methyl-dimethyl copolymer siloxane and 20-30 parts of n-butyl ether, fill with nitrogen to replace oxygen, and then add 1-3 parts of tetramethylammonium bromide, stir and react at a temperature of 80-90°C for 3-6 hours, remove the solvent and separate to obtain a branched polysilicone.

[0017] Furthermore, the preparation process of the modified attapulgite is as follows: the attapulgite and 98% hydrochloric acid solution are mixed according to the solid-liquid ratio of 1g:15-25ml, first immersed for 10-20min, stirred and mixed for 1-2h, and the solid is separated; then 3-6 parts of silane coupling agent are added thereto, ultrasonically treated at a temperature of 70-80°C and a power of 700-800W for 15-25min, and the modified attapulgite is obtained by filtration and separation.

[0018] Furthermore, the preparation process of the polyurethane urea elastomer in step S3 is as follows: polycarbonate diol, isophorone diisocyanate and dibutyltin dilaurate in a molar ratio of 1:1.3-1.6:0.01-0.02 are stirred at a temperature of 80-100°C under nitrogen protection for 25-35 minutes; then the temperature is lowered to 40-50°C, N,N-dimethylformamide and 4-dibenzoic acid dihydrazide are added thereto, the molar ratio of N,N-dimethylformamide, 4-dibenzoic acid dihydrazide and polycarbonate diol is 0.6-0.8:0.3-0.6:1, the reaction is stirred at a rate of 500-700r / min for 40-60min, and the polyurethane urea elastic material is obtained after vacuum drying.

[0019] Furthermore, in step S3, the mixing is carried out at a temperature of 220-240° C. and a speed of 600-800 r / min for 35-45 min.

[0020] Furthermore, in step S4, the extrusion temperature is 180-220° C. and the screw speed is 100-200 rpm.

[0021] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0022] The invention firstly processes the automobile waste modified plastic PP with a plasma device, so that the original waste plastic PP contains more surface functional groups, has a low polymerization degree and an improved crystallinity, which is convenient for adding subsequent grafting modification points; in the blending, inorganic lithium salt, branched polysilanol, modified attapulgite and polyurethane urea elastomer are respectively added for melt modification, and the inorganic lithium salt forms a more stable interaction with the polar groups on the surface of the waste plastic, reduces the water absorption, and changes the arrangement mode and interaction of the molecular chain, so that the movement of the molecular chain is easier, thereby improving the flexibility; the attapulgite is modified by a silane coupling agent after being acid washed, and the long carbon chain of the silane coupling agent has The organic cations enter the interlayers of the attapulgite to improve its adhesion ability, and at the same time interact with the branched polysilicone and the waste plastic molecular chains to produce a high degree of entanglement, forming a tightly connected three-dimensional network structure; the prepared polyurethane urea elastomer is dispersed in the form of tiny particles, which can improve the density and strength of the material, and the cross-linked structure and elastic chain segments, the hard segment content of which is controlled at 40-45%, can enhance the bonding force between the molecular chains, so that it has excellent mechanical properties and toughness; through the above technical features, the recycled modified plastic PP prepared by the present invention has good performance, can be added as a main component, and used in the production process of automobile plastics. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The raw materials used in the present invention are as follows:

[0025] Polycaprolactone triol was purchased from Hubei Shishun Biotechnology Co., Ltd. SS0150; (3-glycidyloxypropyl) methyl-dimethyl copolymer siloxane was purchased from Jinjinle Chemical Co., Ltd.; tetramethylammonium bromide was purchased from Shanghai Yuanye Biotechnology Co., Ltd. S30320; attapulgite was purchased from Shanghai Yuanye Biotechnology Co., Ltd. T22058; silane coupling agent was purchased from Wuhan Nengren Pharmaceutical Chemical Co., Ltd. 132; polycarbonate diol was purchased from Hubei Jusheng Technology Co., Ltd. JS7565; isophorone diisocyanate was purchased from Jinan Huifengda Chemical Co., Ltd. 1274; dibutyltin dilaurate was purchased from Jinan Century Tongda Chemical Co., Ltd. 1242; N,N-dimethylformamide was purchased from Shanghai Yuanye Biotechnology Co., Ltd. S25170; p-Dibenzoic acid dihydrazine was purchased from Shanghai Yuanye Biotechnology Co., Ltd. S70279; polyurethane urea elastomer was purchased from Hubei Tosoh Chemical Technology Co., Ltd. 142.

[0026] Example 1

[0027] This embodiment provides a method for recycling modified plastics for automobiles, comprising the following steps:

[0028] S1: crushing the waste modified plastic PP for automobiles into 1-3 cm; washing to remove the sand and oil; four-stage flotation to remove impurities; drying at 80℃ for 1h;

[0029] S2: placing the dried automobile waste modified plastic PP particles in step S1 in a plasma reaction device (the plasma reaction device is a double-layer dielectric flat plate structure dielectric barrier discharge plasma reactor, and the solid dielectric spheres are made of zirconium oxide ceramic and barium titanate ceramic respectively), purging with helium at room temperature, and plasma treatment for 1 hour at a discharge power of 10 W and a carrier gas flow rate of 45 mL / min; obtaining pretreated automobile waste modified plastic PP particles;

[0030] S3: 300 g of polycaprolactone triol, 180 g of (3-glycidyloxypropyl) methyl-dimethyl copolymer siloxane and 400 g of n-butyl ether were charged with nitrogen to replace oxygen, and then 20 g of tetramethylammonium bromide was added, and the mixture was stirred at 80° C. and 500 r / min for 3 h, and the solvent was removed and separated to obtain a branched polysilanol;

[0031] Take the attapulgite and 98% hydrochloric acid solution according to the solid-liquid ratio of 1g:15ml, soak for 10min, stir and mix at a rate of 600r / min for 1h, and separate the solid; then add 60g of silane coupling agent, ultrasonically treat at a temperature of 70°C and a power of 700W for 15min, and filter and separate to obtain the modified attapulgite;

[0032] Polycarbonate diol, isophorone diisocyanate and dibutyltin dilaurate in a molar ratio of 1:1.3:0.01 were stirred at a rate of 600 r / min for 25 min at a temperature of 80°C under nitrogen protection; then the temperature was lowered to 40°C, N,N-dimethylformamide and dihydrazine p-dibenzoate were added thereto, the molar ratio of N,N-dimethylformamide, dihydrazine p-dibenzoate and polycarbonate diol was 0.6:0.3:1, stirred at a rate of 500 r / min for 40 min, and vacuum dried to obtain a polyurethane urea elastic material;

[0033] 1600 g of the modified automobile waste plastic particles in step S2, 100 g of lithium nitrate, 200 g of branched polysilanol, 60 g of modified attapulgite and 200 g of polyurethane urea elastomer were placed in a reaction kettle and stirred and mixed; 6 g of dispersant polyethylene wax and 8 g of antioxidant pentaerythritol tetra(bis-T-butyl hydroxyhydrocinnamate) were added thereto, and the mixture was kneaded at a temperature of 220° C. and a speed of 600 r / min for 35 min;

[0034] S4: re-plasticizing and extruding, the extrusion temperature is 180°C, the screw speed is 100rpm, and cooling and granulation are performed to obtain recycled plastic particles.

[0035] Example 2

[0036] This embodiment provides a method for recycling modified plastic PP for automobiles, comprising the following steps:

[0037] S1: crushing the waste modified plastic PP for automobiles into 1-3 cm; washing to remove sediment and oil; four-stage flotation to remove impurities; drying at 80℃ for 1h;

[0038] S2: placing the dried automobile waste modified plastic PP particles in step S1 in a plasma reaction device (the plasma reaction device is a double-layer dielectric flat plate structure dielectric barrier discharge plasma reactor, and the materials of the solid dielectric spheres are zirconia ceramic and barium titanate ceramic respectively), purging with helium at room temperature, and plasma treatment for 3 hours at a discharge power of 30W and a carrier gas flow rate of 65mL / min; obtaining pretreated automobile waste modified plastic particles;

[0039] S3: Take 500g of polycaprolactone triol, 260g of (3-glycidyloxypropyl) methyl-dimethyl copolymer siloxane and 600g of n-butyl ether, fill with nitrogen to replace oxygen, then add 60g of tetramethylammonium bromide, stir at 90°C and 600r / min for 6h, remove the solvent and separate to obtain branched polysilanol;

[0040] Take the attapulgite and 98% hydrochloric acid solution according to the solid-liquid ratio of 1g:25ml, soak for 20min, stir and mix at a rate of 800r / min for 2h, and separate the solid; then add 120g of silane coupling agent, ultrasonically treat at a temperature of 80°C and a power of 800W for 25min, and filter and separate to obtain the modified attapulgite;

[0041] Polycarbonate diol, isophorone diisocyanate and dibutyltin dilaurate in a molar ratio of 1:1.6:0.02 were stirred at a rate of 600 r / min for 35 min at a temperature of 100°C under nitrogen protection; then the temperature was lowered to 50°C, N,N-dimethylformamide and dihydrazine p-dibenzoate were added thereto, the molar ratio of N,N-dimethylformamide, dihydrazine p-dibenzoate and polycarbonate diol was 0.8:0.6:1, stirred at a rate of 700 r / min for 60 min, and vacuum dried to obtain a polyurethane urea elastic material;

[0042] 2000 g of the modified waste plastic particles for automobiles in step S2, 200 g of lithium nitrate, 300 g of branched polysilanol, 140 g of modified attapulgite and 400 g of polyurethane urea elastomer were placed in a reaction kettle and stirred and mixed; 10 g of dispersant polyethylene wax and 12 g of antioxidant pentaerythritol tetra(bis-T-butyl hydroxyhydrocinnamate) were added thereto, and the mixture was kneaded at a temperature of 240° C. and a speed of 800 r / min for 45 min;

[0043] S4: re-plasticizing and extruding, the extrusion temperature is 220°C, the screw speed is 200rpm, and cooling and granulation are performed to obtain recycled plastic particles.

[0044] Example 3

[0045] This embodiment provides a method for recycling modified plastic PP for automobiles, comprising the following steps:

[0046] S1: crushing the waste modified plastic PP for automobiles into 1-3 cm; washing to remove sediment and oil; four-stage flotation to remove impurities; drying at 80℃ for 1h;

[0047] S2: placing the dried automobile waste modified plastic PP particles in step S1 in a plasma reaction device (the plasma reaction device is a double-layer dielectric flat plate structure dielectric barrier discharge plasma reactor, and the materials of the solid dielectric spheres are zirconia ceramic and barium titanate ceramic respectively), purging with helium at room temperature, and plasma treatment for 2.5 hours at a discharge power of 25W and a carrier gas flow rate of 60mL / min; obtaining pretreated automobile waste modified plastic particles;

[0048] S3: Take 400g of polycaprolactone triol, 220g of (3-glycidyloxypropyl) methyl-dimethyl copolymer siloxane and 500g of n-butyl ether, fill with nitrogen to replace oxygen, then add 40g of tetramethylammonium bromide, stir at 85°C and 600r / min for 5h, remove the solvent and separate to obtain branched polysilanol;

[0049] The attapulgite and 98% hydrochloric acid solution were mixed at a solid-liquid ratio of 1g:20ml, immersed for 16min, stirred and mixed at a rate of 600r / min for 1.5h, and the solid was separated; 100g of silane coupling agent was added thereto, ultrasonically treated at a temperature of 75°C and a power of 780W for 20min, and filtered to obtain the modified attapulgite;

[0050] Polycarbonate diol, isophorone diisocyanate and dibutyltin dilaurate in a molar ratio of 1:1.5:0.015 were stirred at a rate of 600 r / min for 30 min at a temperature of 95°C under nitrogen protection; then the temperature was lowered to 45°C, N,N-dimethylformamide and dihydrazine p-dibenzoate were added thereto, the molar ratio of N,N-dimethylformamide, dihydrazine p-dibenzoate and polycarbonate diol was 0.7:0.5:1, stirred at a rate of 650 r / min for 55 min, and vacuum dried to obtain a polyurethane urea elastic material;

[0051] 1900 g of the modified waste plastic particles for automobiles in step S2, 160 g of lithium sulfate, 240 g of branched polysilanol, 100 g of modified attapulgite and 300 g of polyurethane urea elastomer were placed in a reaction kettle and stirred and mixed; 8 g of dispersant polyethylene wax and 10 g of antioxidant pentaerythritol tetra(bis-T-butyl hydroxyhydrocinnamate) were added thereto, and the mixture was kneaded at a temperature of 235° C. and a speed of 750 r / min for 40 min;

[0052] S4: re-plasticizing and extruding, the extrusion temperature is 200°C, the screw speed is 180rpm, and cooling and granulation are performed to obtain recycled plastic particles.

[0053] Comparative Example 1

[0054] The difference from Example 1 is that step S2 is missing, that is, no plasma treatment is performed.

[0055] Comparative Example 2

[0056] The difference from Example 1 is that the branched polysilanol is missing in step S2, and the other steps remain unchanged.

[0057] Comparative Example 3

[0058] The difference from Example 1 is that the modified attapulgite is missing in step S2, and the other steps remain unchanged.

[0059] Comparative Example 4

[0060] The difference from Example 1 is that the polyurethane urea elastic material is missing in step S2, and the other steps remain unchanged.

[0061] Comparative Example 5

[0062] The difference from Example 1 is that lithium nitrate is missing in step S2, and the other steps remain unchanged.

[0063] Performance Test:

[0064] Bending strength: tested in accordance with GB / T9341-2000, the test speed is 5mm / min; Notched impact strength: tested in accordance with GB / T1843-2008, the test is carried out at a temperature of 23°C and a humidity of 50%; Tensile strength: tested in accordance with GB / T1040-2006; Elongation at break: tested in accordance with GB / T 23257-2009; Heat deformation temperature: tested in accordance with GB / T 1634-2004; The results are shown in the following table.

[0065] Table 1

[0066]

[0067] From the above performance test results, it can be seen that the recycled plastic particles prepared in Examples 1-3 have good mechanical properties such as tensile strength, bending strength, and heat deformation temperature. In particular, the comprehensive performance of Example 3 is the most outstanding. However, since Comparative Examples 1-5 do not adopt the necessary technical solutions, their corresponding performance tests are significantly worse than those of the Examples. The above experimental results further prove the importance of the technical solutions defined in the present invention for its technical effects.

[0068] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for recycling modified plastics for automobiles, characterized in that: The steps include: S1: Crushing, cleaning, removing impurities and drying of waste modified plastic PP for automobiles; S2: using plasma treatment to obtain pre-treated automobile waste modified plastic PP particles; S3: 80-100 parts by weight of the waste modified plastic PP particles for automobiles prepared in step S2, 5-10 parts of inorganic lithium salt, 10-15 parts of branched polysilanol, 3-7 parts of modified attapulgite and 10-20 parts of polyurethane urea elastomer are placed in a reaction kettle and stirred and mixed; a dispersant and an antioxidant are then added thereto and mixed; S4: After plasticizing, extruding, cooling and granulating, the recycled plastic particles are obtained.

2. The method for recycling modified plastics for automobiles according to claim 1, characterized in that: In step S1, the particles are crushed to 1-3 cm; the particles are cleaned to remove sediment and oil; impurities are removed by four-stage flotation; and the particles are dried at 80° C. for 1 hour.

3. The method for recycling modified plastics for automobiles according to claim 1, characterized in that: The plasma treatment process in step S2 is as follows: placing the dried automobile waste modified plastic PP particles in a plasma reaction device, purging with helium at room temperature, and performing plasma treatment for 1-3 hours at a discharge power of 10-30 W and a carrier gas flow rate of 45-65 mL / min.

4. The method for recycling modified plastics for automobiles according to claim 3, characterized in that: The plasma reaction device is a double-layer dielectric flat plate structure dielectric barrier discharge plasma reactor, and the materials of the solid dielectric spheres are respectively zirconia ceramic and barium titanate ceramic.

5. The method for recycling modified plastics for automobiles according to claim 1, characterized in that: The inorganic lithium salt in step S3 is one or a mixture of lithium nitrate or lithium sulfate.

6. The method for recycling modified plastics for automobiles according to claim 1, characterized in that: The preparation process of the branched polysiloxane is as follows: 15-25 parts of polycaprolactone triol, 9-13 parts of (3-glycidyloxypropyl) methyl-dimethyl copolymer siloxane and 20-30 parts of n-butyl ether are taken, nitrogen is introduced to replace oxygen, and then 1-3 parts of tetramethylammonium bromide are added, and the reaction is stirred at a temperature of 80-90° C. for 3-6 hours, and the solvent is removed and separated to obtain the branched polysiloxane.

7. The method for recycling modified plastics for automobiles according to claim 1, characterized in that: The preparation process of the modified attapulgite is as follows: attapulgite and 98% hydrochloric acid solution are mixed according to a solid-liquid ratio of 1g:15-25ml, first immersed for 10-20min, stirred and mixed for 1-2h, and solid matter is separated; then 3-6 parts of silane coupling agent are added thereto, ultrasonically treated at a temperature of 70-80°C and a power of 700-800W for 15-25min, and filtered and separated to obtain the modified attapulgite.

8. The method for recycling modified plastics for automobiles according to claim 1, characterized in that: The preparation process of the polyurethane urea elastomer in step S3 is as follows: polycarbonate diol, isophorone diisocyanate and dibutyltin dilaurate in a molar ratio of 1:1.3-1.6:0.01-0.02 are stirred at a temperature of 80-100°C under nitrogen protection for 25-35 minutes; then the temperature is lowered to 40-50°C, N,N-dimethylformamide and 4-dibenzoic acid dihydrazide are added thereto, the molar ratio of N,N-dimethylformamide, 4-dibenzoic acid dihydrazide and polycarbonate diol is 0.6-0.8:0.3-0.6:1, the reaction is stirred at a rate of 500-700r / min for 40-60min, and the polyurethane urea elastic material is obtained after vacuum drying.

9. The method for recycling modified plastics for automobiles according to claim 1, characterized in that: In step S3, the mixing is carried out at a temperature of 220-240° C. and a speed of 600-800 r / min for 35-45 min.

10. The method for recycling modified plastics for automobiles according to claim 1, characterized in that: In step S4, the extrusion temperature is 180-220° C. and the screw speed is 100-200 rpm.

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