A kind of polystyrene cleaning material and preparation method thereof

Abstract

The present application relates to the field of expandable polystyrene, and specifically discloses a polystyrene cleaning material and a preparation method thereof. The preparation method of the polystyrene cleaning material comprises the following steps: S1, crushing, melting, extruding and granulating the recycled foamed polystyrene after cleaning to obtain polystyrene particles; S2, mixing the polystyrene particles with styrene, a dispersant, an emulsifier, a filler, and a flame retardant, stirring evenly, and preparing a blend; S3, mixing the blend with toluene, phosphate, and water, polymerizing for 4-5 hours, adding a foaming agent and water, and keeping the temperature and pressure for 4-5 hours after immersion and foaming, cooling, discharging, washing, centrifuging, drying, and mixing with a coating agent. The polystyrene cleaning material of the present application has the advantages of less residual styrene monomer, high mechanical strength, and not easy to generate friction noise; in addition, the preparation method of the present application has the advantages of no need to crack the recycled polystyrene into styrene monomer for reuse, simple preparation method, and low energy consumption.

Description

Technical Field

[0001] The present application relates to the field of expandable polystyrene, and more specifically, to a polystyrene cleaning material and a preparation method thereof. Background Art

[0002] Polystyrene is a polymer synthesized by free radical polymerization of styrene monomers. Due to its advantages of low cost, easy processing, rigidity, insulation, good printability, etc., it is widely used in the light industry market, daily decoration, lighting instructions and packaging. Among them, expanded polystyrene is a hard and tough closed-cell foam. It is made of pure water and styrene as the main materials, benzoyl peroxide and tert-butyl perbenzoate as initiators, pentane as a foaming agent, and auxiliary materials such as molecular weight regulators. It is made by stirring, heating, suspension polymerization, washing, screening and other steps. Expanded polystyrene beads containing foaming agents can be made into foam plastic products through pre-foaming, aging and foam molding. Foamed polystyrene foam plastic products are currently extremely valuable insulation, heat insulation, thermal insulation and packaging cushioning materials.

[0003] At present, the annual output of expanded polystyrene in China has reached more than 7 million tons. However, in the process of processing expanded polystyrene, it is inevitable to produce foam waste, cutting scraps and other wastes. In addition, the expanded polystyrene used for packaging also becomes waste after one-time use, which leads to the generation of a large amount of waste expanded polystyrene materials. Expanded polystyrene materials are large in volume, light in weight, and chemically stable. They are also the most difficult materials to biodegrade, causing great harm to the ecological environment. Therefore, the recycling of expanded polystyrene materials has become a current environmental protection hotspot.

[0004] Methods for recycling expanded polystyrene have involved mechanical, chemical and / or dissolution techniques. The mechanical recycling process first involves a shredding step for volume reduction purposes, and then the recycled expanded polystyrene flakes are melted in an extruder and converted into crude expanded polystyrene pellets after cooling. However, this crude expanded polystyrene contains more impurities and can only be used to make low-quality objects. The chemical recycling process involves the thermal depolymerization of expanded polystyrene and the production of styrene monomers. During the thermal decomposition of recycled expanded polystyrene, other monocyclic aromatic compounds are formed, making styrene purification difficult and resulting in expanded polystyrene with lower mechanical properties. The recycled expanded polystyrene is cracked into styrene monomers using organic solvents, which uses a large amount of organic solvents, is costly, and has a complex process. Summary of the invention

[0005] In order to directly produce expandable polystyrene from recycled foamed polystyrene without cracking the recycled polystyrene into styrene monomer for reuse, the present application provides a polystyrene cleaning material and a preparation method thereof which has a simple process, low energy consumption and reduces styrene monomer residue.

[0006] In the first aspect, the present application provides a method for preparing a polystyrene cleaning material, using the following technical solution:

[0007] A method for preparing a polystyrene cleaning material comprises the following steps:

[0008] S1, washing the recycled expanded polystyrene, crushing, melting, extruding and granulating the polystyrene to obtain polystyrene particles;

[0009] S2, mixing 45-391.8 parts by weight of the polystyrene particles with 58.3-150 parts by weight of styrene, 3-6 parts by weight of a dispersant, 4-10 parts by weight of an emulsifier, 4-8 parts by weight of a filler, and 5-10 parts by weight of a flame retardant, stirring evenly to obtain a blend;

[0010] S3. Mix the blend with 0.4-1 parts by weight of toluene, 1-1.4 parts by weight of phosphate and 50-330 parts by weight of water, carry out polymerization reaction for 4-5 hours, add 15.5-20.5 parts by weight of foaming agent and 25-200 parts by weight of water, soak and foam, and then keep warm and pressurized for 4-5 hours, cool, discharge, wash, centrifuge and dry to obtain recycled polystyrene, mix the recycled polystyrene with the coating agent evenly to obtain a polystyrene cleaning material.

[0011] By adopting the above technical scheme, the recycled polystyrene is melted and extruded into granules, and then the polystyrene particles are mixed and dissolved with monomer styrene to obtain a liquid, and fillers, dispersants, emulsifiers and flame retardants are added at the same time to make the obtained blend dispersed more evenly and stably, and then intermittent production is carried out using a suspended polymer method, and the monomer is dispersed in water in the form of droplets with the help of mechanical stirring force to carry out a suspended polymerization reaction. The reacted material is washed, centrifugally dried, mixed with a coating agent, etc. to obtain a finished product; the melting method is used to recycle waste polystyrene, the process is simple, the prepared monomer has high purity, the cost is low, and it is suitable for industrial production, and there is no need to use an organic solvent to dissolve the recycled polystyrene into styrene monomer for reuse, which reduces the residual styrene monomer in the product, makes the product structure more stable, improves the product manufacturing rate, and increases the overall recycling efficiency.

[0012] Optionally, silane-modified carbon microspheres are further added to S2, and the amount of silane-modified carbon microspheres used is 2-5wt% of the amount of the polystyrene particles used.

[0013] By adopting the above technical scheme, after the polystyrene is foamed, when the foamed bodies rub against each other or against other resin components or metals such as steel plates, "squeaking" and unpleasant friction noise (stick-slip phenomenon) is easily generated. The polystyrene particles are mixed with silane-modified carbon microspheres. After the surface of the carbon microspheres is modified by silane, the dispersion stability of the carbon microspheres and raw materials such as polystyrene particles and styrene is improved. Due to the high surface hardness of the carbon microspheres, they can maintain their spherical structure, thereby playing their ball bearing and filling role, reducing the surface friction of the polystyrene cleaning material after foaming and reducing the possibility of noise generation.

[0014] Optionally, the preparation method of the silane-modified carbon microspheres is as follows:

[0015] The carbon microspheres are added to a mixture of anhydrous ethanol and deionized water, and a silane coupling agent KH550 is added after ultrasonic treatment. After ultrasonic treatment, the mixture is heated to 80-90°C, kept warm for 10-12 hours, cooled to room temperature, centrifuged, washed, and vacuum dried to obtain pretreated carbon microspheres, wherein the amount of the silane coupling agent is 2-3wt% of the amount of the carbon microspheres.

[0016] Dissolve polyvinyl alcohol in deionized water to prepare a polyvinyl alcohol solution with a concentration of 3-5wt%, add graphene oxide, linseed oil and EVA particles, mix well, and prepare a spray liquid, wherein the mass ratio of polyvinyl alcohol, graphene oxide, linseed oil and EVA particles is 2:0.5-0.8:0.4-0.6:0.3-0.5;

[0017] The spraying liquid is uniformly sprayed on the surface of the pretreated carbon microspheres and dried to obtain silane-modified carbon microspheres.

[0018] By adopting the above technical scheme, the carbon microspheres are first pretreated with a silane coupling agent KH550, and long-chain alkyl groups and carbon-carbon double bonds are introduced on the surface of the carbon microspheres, which can reduce the surface energy of the carbon microspheres and improve their dispersion ability; a spray liquid containing polyvinyl alcohol, graphene oxide, linseed oil and EVA particles is applied to the pretreated carbon microspheres. Under the adhesion of polyvinyl alcohol, polyvinyl alcohol, graphene oxide and other components are adhered to the surface of the pretreated carbon microspheres. After drying, polyvinyl alcohol and linseed oil form a blended film, and graphene oxide has excellent mechanical properties. After the polyvinyl alcohol and linseed oil are cured into a film, the graphene oxide spreads and disperses in the blended film, presenting rigid characteristics, effectively bearing and transferring external load forces, and reducing the degree of damage to the material by external forces, which is manifested in the improvement and enhancement of the hardness of the polymer. Moreover, graphene oxide has attracted great attention due to its excellent self-lubrication, unique two-dimensional planar structure and good tribological properties. It can effectively improve the lubrication film-forming properties of the polyvinyl alcohol and linseed oil blend film and reduce friction. Linseed oil is a drying vegetable oil and can effectively increase the lubricity of graphene oxide. EVA particles are low-melting point EVA particles. When suspended and polymerized, the silane-modified carbon microspheres are fixed on the EVA particles by the blend film and are hot-melted and flowed, thereby forming pores in the blend film, thereby absorbing the noise generated by friction of the foamed polystyrene molding. The flowing EVA is solidified in the polystyrene cleaning material, increasing the adhesion between the polystyrene particles and improving the mechanical strength. Moreover, the EVA coated on the polystyrene beads can further reduce the friction noise.

[0019] Optionally, the EVA particles are pretreated as follows:

[0020] The EVA particles are blended with the initiator, extruded and granulated, and the mass ratio of the initiator to the pretreated carbon microspheres is 0.3-0.5:1.

[0021] By adopting the above technical scheme, the pretreated carbon microspheres are impregnated with negative pressure to load the initiator. After the EVA particles are hot-melted and flow out, the initiator flows out together with the EVA particles and polymerizes with styrene monomer or low molecular weight polystyrene in an undirectional free radical manner, thereby reducing the molecular defects in waste polystyrene plastics. Because the molecular chain length can be increased, the physical and chemical properties of the polystyrene cleaning material can be significantly improved.

[0022] Optionally, the filler is selected from at least one of calcium carbonate, graphite powder, sericite, talc and stearate.

[0023] By adopting the above technical solution, the filler is physically dispersed and combined with the beads in the polystyrene. The filler has good thermal stability and can adhere to the phase interface of the polystyrene skeleton, effectively reducing the decomposition rate of polystyrene at high temperature and improving the thermal stability of polystyrene.

[0024] Optionally, the filler is pretreated as follows:

[0025] The filler is dried, ethanol is added, and stirred evenly to prepare a suspension, and a silane coupling agent of 2-2.5 wt% of the filler mass is added in a water bath at 80-90° C., and stirred for 1-2 hours, and dried to prepare a modified filler;

[0026] The modified filler is mixed with polycarbonate, extruded, granulated and ground to obtain a filler with a particle size of 1-3 μm, and the mass ratio of the modified filler to the polycarbonate is 1:0.1-0.3.

[0027] By adopting the above technical scheme, after the filler is modified with a silane coupling agent, its surface can combine with smaller layered particles, which is helpful for the adsorption of the filler on polystyrene and improves the bending strength and impact resistance of polystyrene. It is then mixed with polycarbonate for granulation. Polycarbonate itself has good elasticity, which can improve the tensile strength and fracture resistance of polystyrene. Moreover, polystyrene and polycarbonate have good compatibility, which can enhance the dispersion and stability of the filler in polystyrene. In addition, polycarbonate has a certain lubricating effect, which can reduce the friction coefficient of the polystyrene surface and reduce the generation of friction noise.

[0028] Optionally, the emulsifier comprises sodium lauryl sulfate and gum arabic in a mass ratio of 1:0.8-1;

[0029] The dispersant is selected from at least one of polyvinyl pyrrolidone, polyacrylamide and polyethylene glycol.

[0030] By adopting the above technical solution, sodium dodecyl sulfate and gum arabic do not pollute water, and the dispersant makes the polystyrene particles and styrene more fully soluble, making the early suspension polymerization more stable and reducing the residual substances after the reaction.

[0031] Optionally, the polystyrene particles account for 35-70% of the total weight of the polystyrene cleaning material raw material.

[0032] By adopting the above technical solution, the proportion of polystyrene particles made by extruding recycled polystyrene in the polystyrene cleaning material can reach 70%, and a polystyrene cleaning material with high purity, little styrene residue and stable product structure can still be produced.

[0033] Optionally, the flame retardant includes an organic bromine flame retardant and magnesium hydroxide in a mass ratio of 1:0.4-0.6.

[0034] By adopting the above technical scheme, magnesium hydroxide has strong polarity and is easy to absorb water, which is beneficial to the foaming of polystyrene beads, can reduce carbon emissions, and is more energy-saving and environmentally friendly. Bromide and magnesium hydroxide have different decomposition temperatures and play a low-temperature and medium-temperature flame retardant role respectively. Due to their different decomposition mechanisms, they can more effectively block the burning body and air and improve flame retardancy.

[0035] Optionally, the phosphate comprises tricalcium phosphate and calcium hydrogen phosphate in a mass ratio of 1:0.3-0.5.

[0036] By adopting the above technical solution, tricalcium phosphate and calcium hydrogen phosphate can form an effective suspension stabilizer to improve the mixing stability of the blend and the foaming agent.

[0037] Optionally, the coating agent is used in an amount of 10-15% of the mass of the recycled polystyrene, and the coating agent comprises triglyceride and zinc stearate in a mass ratio of 1:0.8-1.

[0038] By adopting the above technical solution, the recycled polystyrene is mixed with the coating agent, and the coating agent can improve the lubricity of the recycled polystyrene to prevent the prepared polystyrene cleaning material from agglomerating during foaming downstream.

[0039] Optionally, the polymerization reaction temperature is 90-95° C., the impregnation foaming temperature is 65-85° C., and the impregnation foaming pressure is 0.2-0.4 MPa.

[0040] In a second aspect, the present application provides a polystyrene cleaning material, which adopts the following technical solution:

[0041] A polystyrene cleaning material is prepared by adopting a preparation method of the polystyrene cleaning material.

[0042] In summary, this application has the following beneficial effects:

[0043] 1. Since the present application adopts the method of hot-melt extrusion of recycled polystyrene, blending with styrene monomer to dissolve into liquid, and then adopting suspension polymerization for production, there is no need to crack the recycled polystyrene into styrene monomer for reuse. The process is simple, with low energy consumption, and can reduce the production cost of expandable polystyrene. The manufactured polystyrene has high purity, less residual styrene monomer, and a more stable structure, which effectively improves the product manufacturing rate.

[0044] 2. In the present application, it is preferred to add silane-modified carbon microspheres when mixing polystyrene particles with raw materials such as a dispersant. The silane-modified carbon microspheres can be evenly dispersed during the preparation of polystyrene and act as lubricating balls in the polystyrene to reduce the surface friction of the polystyrene and reduce the generation of noise.

[0045] 3. In the present application, it is preferred to use a spraying liquid containing raw materials such as polyvinyl alcohol, graphene oxide and EVA particles to spray the carbon microspheres treated with a silane coupling agent when preparing silane-modified carbon microspheres, which can further increase the surface lubrication effect of the silane carbon microspheres and improve the tensile strength of polystyrene. Adding an initiator to the EVA particles can further increase the molecular chain length and reduce the content of styrene monomer. DETAILED DESCRIPTION

[0046] The following examples further illustrate the present application in detail.

[0047] Preparation Example 1-8 of Silane-modified Carbon Microspheres

[0048] Preparation Example 1: (1) 2 g of glucose and 0.1 g of oxalic acid were added to 50 g of deionized water, treated for 1 h, heated to 180 ° C, reacted for 10 h, cooled to room temperature, centrifuged and washed with anhydrous ethanol and deionized water, and dried at 60 ° C for 12 h to obtain carbon microspheres with a particle size of 0.1 mm;

[0049] (2) 20 g of carbon microspheres were added to a mixture of 800 mL of anhydrous ethanol and 40 mL of deionized water, and ultrasonically treated for 1 h. 0.6 g of silane coupling agent KH550 was added, and the temperature was raised to 80 ° C. and kept warm for 12 h. After cooling to room temperature, centrifugation was performed, washed with deionized water and anhydrous ethanol, and vacuum dried at 60 ° C for 12 h to obtain silane-modified carbon microspheres.

[0050] Preparation Example 2: (1) 2 g of glucose and 0.1 g of oxalic acid were added to 50 g of deionized water, treated for 1 h, heated to 180° C., reacted for 10 h, cooled to room temperature, centrifuged and washed with anhydrous ethanol and deionized water, and dried at 60° C. for 12 h to obtain carbon microspheres with a particle size of 0.1 mm;

[0051] (2) 100 g of carbon microspheres were added to a mixture of 800 g of anhydrous ethanol and 400 g of deionized water, and ultrasonically treated for 1 h. 3 g of silane coupling agent KH550 was added, and the mixture was heated to 80 ° C. and kept warm for 12 h. After cooling to room temperature, the mixture was centrifuged, washed with deionized water and anhydrous ethanol, and vacuum dried at 60 ° C. for 12 h to obtain silane-modified carbon microspheres.

[0052] (3) adding 2 g of polyvinyl alcohol 2699 to deionized water, stirring to dissolve, preparing a polyvinyl alcohol solution with a concentration of 5%, adding 0.8 g of graphene oxide, 0.6 g of linseed oil and 0.5 g of EVA particles, and mixing well to prepare a spraying liquid, wherein the EVA particles are selected from DuPont of the United States, with a brand of 40W and a particle size of 0.01 mm;

[0053] (4) The spraying liquid prepared in step (3) is uniformly sprayed on the surface of the pretreated carbon microspheres prepared in step (2), and dried to obtain silane-modified carbon microspheres.

[0054] Preparation Example 3: (1) 2 g of glucose and 0.1 g of oxalic acid were added to 50 g of deionized water, treated for 1 h, heated to 180 ° C, reacted for 10 h, cooled to room temperature, centrifuged and washed with anhydrous ethanol and deionized water, and dried at 60 ° C for 12 h to obtain carbon microspheres with a particle size of 0.1 mm;

[0055] (2) 100 g of carbon microspheres were added to a mixture of 800 g of anhydrous ethanol and 400 g of deionized water, and ultrasonically treated for 1 h. 2 g of silane coupling agent KH550 was added, and the mixture was heated to 90 ° C. and kept warm for 10 h. After cooling to room temperature, the mixture was centrifuged, washed with deionized water and anhydrous ethanol, and vacuum dried at 60 ° C. for 12 h to obtain silane-modified carbon microspheres.

[0056] (3) adding 2 g of polyvinyl alcohol 2699 to deionized water, stirring to dissolve, preparing a polyvinyl alcohol solution with a concentration of 5%, adding 0.5 g of graphene oxide, 0.4 g of linseed oil and 0.3 g of EVA particles, and mixing well to prepare a spraying liquid, wherein the EVA particles are selected from DuPont of the United States, with a brand of 40W and a particle size of 0.01 mm;

[0057] (4) The spraying liquid prepared in step (3) is uniformly sprayed on the surface of the pretreated carbon microspheres prepared in step (2), and dried to obtain silane-modified carbon microspheres.

[0058] Preparation Example 4: The difference from Preparation Example 2 is that graphene oxide is not added to the spraying liquid.

[0059] Preparation Example 5: The difference from Preparation Example 2 is that linseed oil is not added to the spray liquid.

[0060] Preparation Example 6: The difference from Preparation Example 2 is that no EVA particles are added to the spraying liquid.

[0061] Preparation Example 7: The difference from Preparation Example 2 is that in step (3), the EVA particles are subjected to the following pretreatment: the EVA particles are blended with the initiator, extruded, and granulated, the mass ratio of the initiator to the pretreated carbon microspheres is 0.5:1, and the initiator is dibenzoyl peroxide, diisopropylbenzene peroxide, and azobisisobutyronitrile in a mass ratio of 1:2:2.

[0062] Preparation Example 8: The difference from Preparation Example 2 is that in step (3), the EVA particles are subjected to the following pretreatment: the EVA particles are blended with the initiator, extruded, and granulated, the mass ratio of the initiator to the pretreated carbon microspheres is 0.3:1, and the initiator is dibenzoyl peroxide, diisopropylbenzene peroxide, and azobisisobutyronitrile in a mass ratio of 1:1:1.

[0063] Example

[0064] Embodiment 1: A method for preparing a polystyrene cleaning material, comprising the following steps:

[0065] S1, the recycled expanded polystyrene is washed, crushed, melted, extruded and granulated to obtain polystyrene particles, the extrusion temperature is 160°C, the melt mass flow rate of the recycled expanded polystyrene (2.16kg, 230°C) is 12g / 10min, selected from Jinfa Technology Co., Ltd.;

[0066] S2, 391.8kg of the polystyrene particles are mixed with 135kg of styrene, 6kg of dispersant, 10kg of emulsifier, 8kg of filler, and 10kg of flame retardant, and stirred evenly to prepare a blend, wherein the dispersant is polyvinyl pyrrolidone, the emulsifier comprises sodium lauryl sulfate and gum arabic in a mass ratio of 1:1, the filler is graphite powder, and the flame retardant comprises an organic bromine flame retardant and magnesium hydroxide in a mass ratio of 1:0.6, and the organic bromine flame retardant is tetrabromophthalic anhydride;

[0067] S3. Mix the prepared blend with 1kg toluene, 1.4kg phosphate, and 330kg water, heat to 90°C, polymerize at 90°C for 5h, add 20.5kg foaming agent and 200kg water, soak and foam at 85°C and 0.4MPa, then keep warm and pressure for 4h, cool to 45°C, discharge, wash, centrifuge, and dry to obtain recycled polystyrene, mix the recycled polystyrene with a coating agent to obtain a polystyrene cleaning material, the phosphate includes tricalcium phosphate and calcium hydrogen phosphate in a mass ratio of 1:1, the foaming agent is pentane, the coating agent includes triglyceride and zinc stearate in a mass ratio of 1:0.5, and the amount of the coating agent is 10% of the mass of the recycled polystyrene.

[0068] Embodiment 2: A method for preparing a polystyrene cleaning material, comprising the following steps:

[0069] S1, after washing, the recycled expanded polystyrene is crushed, melted, extruded and granulated to obtain polystyrene particles, the extrusion temperature is 180°C, the melt mass flow rate of the recycled expanded polystyrene (2.16kg, 230°C) is 12g / 10min, selected from Jinfa Technology Co., Ltd.;

[0070] S2, 391.8kg of the polystyrene particles are mixed with 58.3kg of styrene, 3kg of dispersant, 4kg of emulsifier, 4kg of filler, and 5kg of flame retardant, and stirred evenly to prepare a blend, wherein the dispersant is polyvinyl pyrrolidone, the emulsifier comprises sodium lauryl sulfate and gum arabic in a mass ratio of 1:1, the filler is calcium carbonate, and the flame retardant comprises an organic bromine flame retardant and magnesium hydroxide in a mass ratio of 1:0.4, and the organic bromine flame retardant is tetrabromophthalic anhydride;

[0071] S3. Mix the prepared blend with 0.4kg toluene, 1.0kg phosphate, and 50kg water, heat to 95°C, polymerize at 95°C for 4h, add 15.5kg foaming agent and 25kg water, soak and foam at 70°C and 0.4MPa, then keep warm and pressure for 5h, cool to 45°C, discharge, wash, centrifuge, and dry to obtain recycled polystyrene, mix the recycled polystyrene with a coating agent to obtain a polystyrene cleaning material, the phosphate includes tricalcium phosphate and calcium hydrogen phosphate in a mass ratio of 1:0.5, the foaming agent is pentane, the coating agent includes triglyceride and zinc stearate in a mass ratio of 1:1, and the amount of the coating agent is 10% of the mass of the recycled polystyrene.

[0072] Embodiment 3: A method for preparing a polystyrene cleaning material, comprising the following steps:

[0073] S1, the recycled expanded polystyrene is washed, crushed, melted, extruded and granulated to obtain polystyrene particles, the extrusion temperature is 170°C, the melt mass flow rate of the recycled expanded polystyrene (2.16kg, 230°C) is 12g / 10min, selected from Kingfa Technology Co., Ltd.;

[0074] S2, 104.5kg of the polystyrene particles are mixed with 145kg of styrene, 5kg of dispersant, 8kg of emulsifier, 7kg of filler, and 8kg of flame retardant, and stirred evenly to obtain a blend, wherein the dispersant is polyvinyl pyrrolidone, the emulsifier comprises sodium lauryl sulfate and gum arabic in a mass ratio of 1:0.8, the filler is calcium carbonate, and the flame retardant comprises an organic bromine flame retardant and magnesium hydroxide in a mass ratio of 1:0.4, and the organic bromine flame retardant is tetrabromophthalic anhydride;

[0075] S3. Mix the prepared blend with 0.8kg toluene, 1.3kg phosphate, and 200kg water, heat to 95°C, polymerize at 95°C for 4h, add 19kg foaming agent and 80kg water, soak and foam at 65°C and 0.2MPa, then keep warm and pressurized for 5h, cool to 50°C, discharge, wash, centrifuge, and dry to obtain recycled polystyrene, mix the recycled polystyrene with a coating agent to obtain a polystyrene cleaning material, the phosphate includes tricalcium phosphate and calcium hydrogen phosphate in a mass ratio of 1:0.3, the foaming agent is pentane, the coating agent includes triglyceride and zinc stearate in a mass ratio of 1:0.8, and the amount of the coating agent is 15% of the mass of the recycled polystyrene.

[0076] Embodiment 4: A method for preparing a polystyrene cleaning material, comprising the following steps:

[0077] S1, after washing, the recycled expanded polystyrene is crushed, melted, extruded and granulated to obtain polystyrene particles, the extrusion temperature is 180°C, the melt mass flow rate of the recycled expanded polystyrene (2.16kg, 230°C) is 12g / 10min, selected from Jinfa Technology Co., Ltd.;

[0078] S2, 45kg of the polystyrene particles are mixed with 150kg of styrene, 3kg of dispersant, 4kg of emulsifier, 4kg of filler, and 5kg of flame retardant, and stirred evenly to obtain a blend, wherein the dispersant is polyvinyl pyrrolidone, the emulsifier comprises sodium lauryl sulfate and gum arabic in a mass ratio of 1:0.9, the filler is calcium carbonate, and the flame retardant comprises an organic bromine flame retardant and magnesium hydroxide in a mass ratio of 1:0.5, and the organic bromine flame retardant is tetrabromophthalic anhydride;

[0079] S3. Mix the prepared blend with 0.4kg toluene, 1.0kg phosphate, and 100kg water, heat to 90°C, polymerize at 90°C for 4h, add 15.5kg foaming agent and 50kg water, soak and foam at 75°C and 0.3MPa, then keep warm and pressure for 5h, cool to 50°C, discharge, wash, centrifuge, and dry to obtain recycled polystyrene, mix the recycled polystyrene with a coating agent to obtain a polystyrene cleaning material, the phosphate includes tricalcium phosphate and calcium hydrogen phosphate in a mass ratio of 1:0.4, the foaming agent is pentane, the coating agent includes triglyceride and zinc stearate in a mass ratio of 1:0.8, and the amount of the coating agent is 13% of the mass of the recycled polystyrene.

[0080] Example 5: A method for preparing a polystyrene cleaning material. The difference from Example 1 is that silane-modified carbon microspheres prepared in Preparation Example 1 are further added in step S2, and the added amount of the silane-modified carbon microspheres is 5wt% of the mass of the polystyrene particles.

[0081] Example 6: A method for preparing a polystyrene cleaning material. The difference from Example 1 is that silane-modified carbon microspheres prepared in Preparation Example 2 are further added in step S2, and the added amount of the silane-modified carbon microspheres is 5wt% of the mass of the polystyrene particles.

[0082] Example 7: A method for preparing a polystyrene cleaning material. The difference from Example 1 is that silane-modified carbon microspheres prepared in Preparation Example 3 are further added in step S2, and the added amount of silane-modified carbon microspheres is 3wt% of the mass of the polystyrene particles.

[0083] Example 8: A method for preparing a polystyrene cleaning material, which is different from Example 6 in that the silane-modified carbon microspheres added in step S2 are prepared from Preparation Example 4.

[0084] Example 9: A method for preparing a polystyrene cleaning material, which is different from Example 6 in that the silane-modified carbon microspheres added in step S2 are prepared from Preparation Example 5.

[0085] Example 10: A method for preparing a polystyrene cleaning material. The difference from Example 6 is that the silane-modified carbon microspheres added in step S2 are prepared from Preparation Example 6.

[0086] Example 11: A method for preparing a polystyrene cleaning material. The difference from Example 6 is that the silane-modified carbon microspheres added in step S2 are prepared from Preparation Example 7.

[0087] Example 12: A method for preparing a polystyrene cleaning material. The difference from Example 6 is that the silane-modified carbon microspheres added in step S2 are prepared from Preparation Example 8.

[0088] Embodiment 13: A method for preparing a polystyrene cleaning material, which differs from Embodiment 11 in that the filler is pretreated as follows:

[0089] 4 kg of filler was dried, added with 80 kg of ethanol, stirred evenly to prepare a suspension, heated in a water bath at 90° C., and 2.5 wt% of the filler mass of a silane coupling agent was added, stirred for 2 h, and dried.

[0090] Embodiment 14: A method for preparing a polystyrene cleaning material, which differs from Embodiment 11 in that the filler is pretreated as follows:

[0091] 4 kg of filler was dried, 80 kg of ethanol was added, and the mixture was stirred evenly to obtain a suspension. The suspension was heated in a water bath at 90° C., and 2.5 wt% of a silane coupling agent was added based on the filler mass. The mixture was stirred for 2 h, and dried to obtain a modified filler.

[0092] The modified filler and polycarbonate are mixed, extruded, granulated and ground to obtain a filler with a particle size of 3 μm. The mass ratio of the modified filler to the polycarbonate is 1:0.3. The polycarbonate is selected from Sinopec Mitsubishi and the product number is 7022IR.

[0093] Embodiment 15: A method for preparing a polystyrene cleaning material, which differs from Embodiment 11 in that the filler is pretreated as follows:

[0094] 4 kg of filler was dried, 80 kg of ethanol was added, and the mixture was stirred evenly to obtain a suspension. The suspension was heated in a water bath at 90° C., and 2.0 wt% of a silane coupling agent was added based on the mass of the filler. The mixture was stirred for 2 h, and dried to obtain a modified filler.

[0095] The modified filler and polycarbonate are mixed, extruded, granulated and ground to obtain a filler with a particle size of 1 μm. The mass ratio of the modified filler to the polycarbonate is 1:0.1. The polycarbonate is selected from Sinopec Mitsubishi and the product number is 7022IR.

[0096] Comparative Example

[0097] Comparative Example 1: A method for preparing expandable polystyrene using waste polystyrene, comprising the following steps: washing the waste polystyrene foam and cutting it into small pieces, adding 120 g of the above polystyrene raw material into 400 mL of dichloromethane solvent, stirring at room temperature for 10 min, adding the above solution into 2000 mL of 1.80×10 -2 mol / L sodium dodecylbenzene sulfonate aqueous solution, control the stirring speed to 300r / min, stir and heat, the heating rate is 0.5℃ / min, when the temperature reaches 45℃, keep it for 55min, then control the heating rate to 0.25℃ / min, heat it to 55℃, keep it for 25min, filter and wash to obtain white polystyrene particles with a particle size of 0.5-1.5mm, retain the dichloromethane solvent and surfactant aqueous solution obtained by distillation for the next cycle.

[0098] Comparative Example 2: A method for preparing expandable polystyrene using recycled polystyrene products, wherein the preparation steps are as follows: 1) washing the recycled polystyrene products and crushing them, heating and melting the crushed materials, and extruding and granulating them using a plastic granulator, wherein the recycled polystyrene products include recycled polystyrene in the process of producing polystyrene;

[0099] 2) putting the polystyrene obtained in step 1) together with the dispersing and isolating agent into a water-added reaction kettle, wherein the mass ratio of polystyrene to the dispersing and isolating agent is 100:0.3, starting the agitator to stir, slowly raising the temperature to 90° C., and maintaining this temperature for 1 hour to obtain a semi-finished polystyrene particle product, wherein the dispersing and isolating agent is sodium tripolyphosphate;

[0100] 3) After the semi-finished polystyrene particles obtained in step 2) become soft, a fluxing agent is added, and the mass ratio of the fluxing agent to the semi-finished polystyrene particles is 100:0.013, and then stirred for 20 minutes. The fluxing agent is a fluxing agent of a foaming agent, and the fluxing agent is sodium alkylbenzene sulfonate;

[0101] 4) closing the reactor, adding a foaming agent to the reactor in step 3), wherein the foaming agent accounts for 7% of the total mixture in step 3), slowly heating to 120° C., and maintaining the temperature and pressure for 4 hours until the foaming agent is completely fused, wherein the foaming agent is pentane;

[0102] 5) Cool the reactor to 35°C, stop stirring, and discharge the material to obtain expandable polystyrene.

[0103] Performance testing

[0104] 1. Prepare polystyrene according to the method in the embodiment and the comparative example, and pass 100°C steam into the prepared polystyrene, keep warm for 3 minutes to obtain pre-foamed polystyrene beads, then place the pre-foamed polystyrene beads for 8-12 hours to allow air to penetrate into the pores and maintain the pressure balance inside and outside the pores. Heat the polystyrene particles with 100°C steam for 30 seconds, at which time the particles will expand again and fill the internal space of the mold, and then cool down to obtain a polystyrene foam board with a length of 80 mm, a width of 10 mm, and a thickness of 4 mm. Test the performance of the foam board according to the following method, and record the test results in Table 1.

[0105] 1. Density: Test in accordance with GB / T6343-2009 "Determination of apparent density of foam plastics and rubber".

[0106] 2. Tensile strength: The test is carried out in accordance with GB / T1040.2-2006 "Determination of tensile properties of plastics Part 2: Experimental conditions for molded and extruded plastics", and the tensile speed is 2mm / min.

[0107] 3. Bending strength: Tested in accordance with GB / T9341-2008 "Determination of flexural properties of plastics".

[0108] 4. Thermal conductivity: Tested in accordance with GB / T10295-8 "Determination of steady-state thermal resistance and related properties of insulating materials - Heat flow meter method".

[0109] 5. Friction coefficient: The obtained polystyrene foam board is made into multiple test pieces with a skin layer on one side, and the test pieces are placed in a constant temperature and humidity chamber at a temperature of 23°C and a humidity of 50% for 12 hours. Then, under the same environment, a surface property tester (manufactured by Shinto Science Co., Ltd., HEIDON model: 14FW) is used to rub the skin layers of two test pieces against each other 5 times with a load of 10N, a reciprocating distance of 50mm, and a sliding speed of 1.0mm / s. Then, during the friction, the static friction coefficient and the dynamic friction coefficient are measured, and the average value of the static friction coefficient and the average value of the dynamic friction coefficient for 5 times (5 times back and forth) are calculated, and the difference between the average value of the static friction coefficient and the average value of the dynamic friction coefficient is calculated, wherein the skin layer refers to the surface of the foamed molded body that directly contacts the inner surface of the mold.

[0110] Table 1

[0111]

[0112] Combining Examples 1-4 and the data in Table 1, it can be seen that different amounts of recycled foamed polystyrene are used to prepare polystyrene cleaning materials in Examples 1-4, and the polystyrene particles in Example 1 account for 391.8 / (391.8+135+6+10+8+10+1+1.4+330+20.5+200)=35.2% of the raw materials used, and the polystyrene particles in Example 2 account for 391.8 / (391.8+58.3+3+4+4+5+0.4+1+50+15.5+25)=70% of the raw materials used. It can be seen that the prepared polystyrene has a low density, high bending strength and tensile strength, low thermal conductivity, and strong thermal insulation.

[0113] Compared with Example 1, Example 5 uses the silane-modified carbon microspheres prepared in Preparation Example 1. Table 1 shows that the tensile strength and flexural strength of the polystyrene cleaning material prepared in Example 5 are increased, the mechanical properties are improved, and the surface friction coefficient is reduced, indicating that the use of silane coupling agent KH550 to treat the carbon microspheres can improve the compatibility of the carbon microspheres with polystyrene particles and improve the mechanical properties.

[0114] In Example 6 and Example 7, the silane-modified carbon microspheres prepared in Preparation Example 2 and Preparation Example 3 were used respectively. Compared with Example 1, the tensile strength and bending strength of the polystyrene cleaning materials prepared in Example 6 and Example 7 were increased, the dynamic friction coefficient and the static friction coefficient were further reduced, and the possibility of generating noise was reduced, indicating that the use of graphene oxide, linseed oil and EVA particles to make a spray liquid and treat the silane-modified carbon microspheres can further improve the mechanical properties of the polystyrene particles and improve their surface lubricity.

[0115] Compared with Example 6, the silane-modified carbon microspheres in Examples 8-10 were prepared from Preparation Example 4, Preparation Example 5 and Preparation Example 6, respectively. Compared with Preparation Example 1, Preparation Example 4, Preparation Example 5 and Preparation Example 6 did not add graphene oxide, linseed oil and EVA particles, respectively. Table 1 shows that compared with Example 6, the mechanical properties such as tensile strength in Examples 8 and 10 decreased, and the friction coefficient increased to. In Example 9, the mechanical strength was not greatly affected, but the friction coefficient increased significantly.

[0116] Compared with Example 6, Example 11 and Example 12 are silane-modified carbon microspheres made from Preparation Example 7 and Preparation Example 8, and the loaded initiator is also impregnated on the EVA particles. Table 1 shows that the tensile strength and flexural strength of the polystyrene cleaning materials prepared in Example 11 and Example 12 are increased, and other properties do not change much.

[0117] Compared with Example 11, in Example 13, a silane coupling agent is further used to pretreat the filler, so that the mechanical properties of the polystyrene cleaning material prepared thereby are improved.

[0118] Compared with Example 11, in Example 14 and Example 15, not only silane coupling agent but also polycarbonate is used for pre-treatment of the filler. The tensile strength and bending strength of the polystyrene cleaning materials prepared in Example 14 and Example 15 are further increased, and the surface static friction coefficient and dynamic friction coefficient are further reduced, and the surface stick-slip phenomenon is weakened.

[0119] Comparative Example 1 is a method in the prior art of dissolving waste polystyrene and mixing it with sodium dodecylbenzene sulfonate to prepare expandable polystyrene particles. Comparative Document 2 is a method in the prior art of preparing expandable polystyrene by mixing and extruding the recycled polystyrene without crushing it. The expandable polystyrene prepared in Comparative Examples 1 and 2 has an increased density, an increased surface friction, and is prone to generating noise.

[0120] 2. Take the polystyrene cleaning materials prepared in Examples 1-2 and 11-12, and detect the residual monomer content and molecular weight in the polystyrene cleaning materials according to the following method, and record the test results in Table 3.

[0121] 1. Molecular weight: Tested in accordance with GB / T21864-2008 "Standard Method for Testing Average Molecular Weight and Molecular Weight Distribution of Polystyrene";

[0122] 2. Residual styrene monomer: Detection shall be carried out in accordance with GB / T4614-1984 "Determination of residual styrene monomer in polystyrene by gas chromatography".

[0123] Table 3

[0124] project Molecular weight Styrene residual monomer Example 1 48000 600ppm Example 2 48000 700ppm Embodiment 11 51500 452ppm Example 12 51000 468ppm

[0125] Table 3 shows that in Example 1, the recovered polystyrene accounts for 70% of the total weight of the raw materials, and in Example 2, the recovered polystyrene accounts for 35% of the total weight of the raw materials. The molecular weight of the polystyrene cleaning material prepared thereby is low in styrene residual monomers. In Examples 11 and 12, the initiator is impregnated in the pretreated carbon microspheres, and the molecular weight of the polystyrene cleaning material obtained thereby is increased, and the styrene residual monomers are further reduced.

[0126] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A method for preparing a polystyrene cleaning material, characterized in that: The following steps are involved: S1, washing the recycled expanded polystyrene, crushing, melting, extruding and granulating the polystyrene to obtain polystyrene particles; S2, mixing 45-391.8 parts by weight of the polystyrene particles with 58.3-150 parts by weight of styrene, 3-6 parts by weight of a dispersant, 4-10 parts by weight of an emulsifier, 4-8 parts by weight of a filler, 5-10 parts by weight of a flame retardant and silane-modified carbon microspheres, stirring evenly to prepare a blend, wherein the amount of the silane-modified carbon microspheres is 2-5wt% of the amount of the polystyrene particles; The preparation method of the silane-modified carbon microspheres is as follows: adding carbon microspheres to a mixture of anhydrous ethanol and deionized water, adding a silane coupling agent KH550 after ultrasonic treatment, heating to 80-90°C after ultrasonic treatment, keeping warm for 10-12 hours, cooling to room temperature, centrifuging, washing, and vacuum drying to obtain pretreated carbon microspheres, wherein the amount of the silane coupling agent is 2-3wt% of the amount of the carbon microspheres; dissolving polyvinyl alcohol in deionized water to obtain a polyvinyl alcohol solution with a concentration of 3-5wt%, adding graphene oxide, linseed oil and EVA particles, mixing evenly, and obtaining a spray liquid, wherein the mass ratio of polyvinyl alcohol, graphene oxide, linseed oil and EVA particles is 2:0.5-0.8:0.4-0.6:0.3-0.5; spraying the spray liquid evenly on the surface of the pretreated carbon microspheres, drying, and obtaining silane-modified carbon microspheres; S3. Mix the blend with 0.4-1 parts by weight of toluene, 1-1.4 parts by weight of phosphate and 50-330 parts by weight of water, carry out polymerization reaction for 4-5 hours, add 15.5-20.5 parts by weight of foaming agent and 25-200 parts by weight of water, soak and foam, and then keep warm and pressurized for 4-5 hours, cool, discharge, wash, centrifuge and dry to obtain recycled polystyrene, mix the recycled polystyrene with the coating agent evenly to obtain a polystyrene cleaning material.

2. The method for preparing a polystyrene cleaning material according to claim 1, wherein: The EVA particles are pretreated as follows: The EVA particles are blended with the initiator, extruded and granulated, and the mass ratio of the initiator to the pretreated carbon microspheres is 0.3-0.5:

1.

3. The method for preparing a polystyrene cleaning material according to claim 1, characterized in that: The filler is selected from at least one of calcium carbonate, graphite powder, sericite, talc and stearate.

4. The method for preparing the polystyrene cleaning material according to claim 3, characterized in that: The filler is pretreated as follows: The filler is dried, ethanol is added, and stirred evenly to prepare a suspension, and a silane coupling agent of 2-2.5 wt% of the filler mass is added in a water bath at 80-90° C., and stirred for 1-2 hours, and dried to prepare a modified filler; The modified filler is mixed with polycarbonate, extruded, granulated and ground to obtain a filler with a particle size of 1-3 μm, and the mass ratio of the modified filler to the polycarbonate is 1:0.1-0.

3.

5. The method for preparing a polystyrene cleaning material according to claim 1, characterized in that: The emulsifier includes sodium lauryl sulfate and gum arabic in a mass ratio of 1:0.8-1; The dispersant is selected from at least one of polyvinyl pyrrolidone, polyacrylamide and polyethylene glycol.

6. The method for preparing the polystyrene cleaning material according to claim 1, characterized in that: The flame retardant comprises an organic bromine flame retardant and magnesium hydroxide in a mass ratio of 1:0.4-0.

6.

7. The method for preparing a polystyrene cleaning material according to claim 1, characterized in that: The phosphate includes tricalcium phosphate and calcium hydrogen phosphate in a mass ratio of 1:0.3-0.

5.

8. A polystyrene cleaning material, characterized in that: The polystyrene cleaning material is prepared by the preparation method of any one of claims 1 to 7.

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