A polystyrene foam plastic granulation process

Abstract

The invention relates to the technical field of foam plastics, in particular to a polystyrene foam plastic granulation process, which recycles waste PS foam materials, crushes the waste PS foam materials into small granular waste materials after cleaning and removing foreign matter, soaks the waste materials with a solvent to remove some additives and impurities, adds the soaked waste materials into a supercritical carbon dioxide reaction, further removes low-molecular impurities, plasticizers and volatile organic matter in the waste materials, mixes and melts the treated waste materials with new materials, filters and then extrudes them through an extruder to obtain strips, and finally cuts the strips into uniform particles through a pelletizer. The granulation process of the invention can efficiently recycle waste PS foam materials, has better product quality, reduces energy consumption and environmental pollution, and can recycle the used solvent.

Description

Technical Field

[0001] The invention relates to the technical field of foam plastics, in particular to a polystyrene foam plastic granulation process. Background Art

[0002] With the development of society, the use of foam plastics is increasing, and the impact on the environment is becoming more and more serious. Therefore, the recycling of polystyrene foam plastics needs to be solved urgently. However, the new products produced by the current granulation process of recycled waste are still insufficient in terms of safety of use, and on the other hand, there will be problems with the performance of the products.

[0003] Therefore, it is necessary to optimize the recycling granulation process to ensure the safety and performance of new products. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a polystyrene foam plastic granulation process, which recycles waste foam plastics and mixes them with new materials for granulation. The performance of the new product can be ensured in the process, and the problem of waste materials polluting the environment is also solved.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A polystyrene foam plastic granulation process specifically comprises the following steps: Step S1, collecting waste polystyrene foam plastics and performing preliminary physical cleaning; Step S2, crushing the waste polystyrene foam plastics cleaned in step S1 into particles, soaking and cleaning them with a solvent, and recycling the solvent; Step S3, adding the soaked and cleaned waste to a supercritical carbon dioxide reactor to further remove impurities in the waste; Step S4, the waste material processed in step S3 is mixed with the new material to melt into a mixed material, and the melted mixed material is filtered, and the filtered mixed material is extruded through an extruder; Step S5, the extruded material is cooled and then cut into uniform particles by a pelletizer.

[0006] Optionally, in one embodiment of the present invention, the solvent is orange peel essential oil extract or any one of ethyl acetate and butanone, and the concentration of the solvent is 10%-100%.

[0007] Optionally, in one embodiment of the present invention, the soaking and cleaning temperature in step S2 is 25°C-40°C, and the soaking time is 30min-2h.

[0008] Optionally, in one embodiment of the present invention, the parameters of the supercritical carbon dioxide reactor in step S3 are specifically as follows: pressure of 8-15 MPa, temperature of 30°C-80°C, reaction time of 30 min-2 h, carbon dioxide flow rate of 10 kg-50 kg / h, and mass ratio of waste to carbon dioxide of 1:2-5.

[0009] Optionally, in one embodiment of the present invention, the physical cleaning is any one of ultrasonic cleaning or high-pressure water jet cleaning.

[0010] Optionally, in one embodiment of the present invention, a high temperature resistant toughening agent, a heat stabilizer, an antioxidant and a foaming agent are added to the mixed material of step S4, the added amount of the toughening agent is 2%-10% of the mass of polystyrene, the added amount of the heat stabilizer is 0.2%-1% of the mass of polystyrene, the added amount of the antioxidant is 0.1%-0.5% of the mass of polystyrene, and the foaming agent is 0.2%-1% of the mass of polystyrene.

[0011] Optionally, in one embodiment of the present invention, the proportion of waste in step S4 is 20%-60%.

[0012] Optionally, in one embodiment of the present invention, the extruder of step S4 is a twin-screw extruder, and the temperature control of the extruder is specifically as follows: the feeding section temperature is 160°C-180°C, the melting section temperature is 180°C-220°C, the metering section temperature is 200°C-230°C, and the extrusion mold temperature is 210°C-240°C.

[0013] Beneficial effects of the present invention The polystyrene foam plastic granulation process of the present invention comprises recycled polystyrene waste materials as raw materials, and the waste materials are subjected to multiple cleaning, which effectively improves the utilization rate of the waste materials, reduces the cost of raw materials, achieves a higher resource recovery efficiency, solves the environmental pollution problem of the waste materials, and complies with the concepts of circular economy and sustainable development. In the cleaning process, a solvent is used for soaking and cleaning, and the solvent is recycled and reused, which reduces the waste of solvent and environmental pollution, and effectively reduces the waste of resources and emissions in the production process. The process also uses supercritical carbon dioxide to foam the materials, which is conducive to environmental protection and reduces the use of traditional foaming agents. The products produced are mixed with waste materials and new materials, which ensures the uniformity and performance of the products. In the mixing and melting process, a variety of additives are added to avoid product performance problems caused by the quality of the waste materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0015] Figure 1This is a process flow chart of polystyrene foam granulation according to Example 1 of the present invention. DETAILED DESCRIPTION

[0016] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments. Example

[0017] In order to meet the concept of environmental protection, a polystyrene foam granulation process was studied. The specific scheme is as follows: like Figure 1 As shown, a polystyrene foam plastic granulation process specifically comprises the following steps: Step S1, collecting waste polystyrene foam plastics and performing preliminary physical cleaning; Step S2, crushing the waste polystyrene foam plastics cleaned in step S1 into particles, soaking and cleaning them with a solvent, and recycling the solvent; Step S3, adding the soaked and cleaned waste to a supercritical carbon dioxide reactor to further remove impurities in the waste; Step S4, the waste material processed in step S3 is mixed with the new material to melt into a mixed material, and the melted mixed material is filtered, and the filtered mixed material is extruded through an extruder; Step S5, the extruded material is cooled and then cut into uniform particles by a pelletizer.

[0018] The solvent is orange peel essential oil extract or any one of ethyl acetate and butanone, and the concentration of the solvent is 10%-100%. In this embodiment, orange peel essential oil extract is preferably used as the solvent. As a natural solvent, it has good environmental protection, is derived from natural plants, does not contain toxic chemicals, and therefore has a small burden on the environment. It has good dissolving ability and is suitable for cleaning polystyrene. The cleaning process is relatively gentle and can avoid the negative effects caused by high temperature or chemical stimulation. Low-pollution waste is soaked and cleaned with a solvent with a concentration of 10%-30%, and heavily polluted waste is soaked and cleaned with a solvent with a concentration of 50%-100%. Generally, the waste is soaked and cleaned with a concentration of 30%-50%. After the use of the orange peel essential oil extract, impurities in the solvent can be removed by adsorption materials such as activated carbon, and pollutants in the solvent can also be separated by heating and distillation. In other schemes, the solvent can be ethyl acetate, which can effectively dissolve polystyrene foam plastics and has a high cleaning efficiency. It can be recycled and reused by simple distillation or other separation methods in the solvent recovery stage.

[0019] In step S2, the immersion cleaning temperature is 25°C-40°C, and the immersion time is 30min-2h. The temperature and time settings are suitable for immersion cleaning of waste materials with different degrees of contamination. Lower temperatures have less effect on the performance of the polystyrene material itself, can reduce solvent volatilization losses, and are conducive to recycling. Properly increasing the temperature can improve the cleaning efficiency of the solvent. Generally, cleaning at 30°C-35°C for 1h is preferred.

[0020] The parameters of the supercritical carbon dioxide reactor in step S3 are specifically as follows: pressure of 8-15 MPa, temperature of 30°C-80°C, reaction time of 30min-2h, carbon dioxide flow rate of 10 kg -50kg / h, mass ratio of waste material to carbon dioxide of 1:2-5, within the range of 8-15 MPa, carbon dioxide can maintain a supercritical state, which can not only give play to its excellent solubility, but also will not cause excessive burden on equipment due to excessive pressure, high pressure helps to improve the solubility and cleaning effect of carbon dioxide, remove organic impurities and residual solvents in waste materials, at 30°C, the solubility of carbon dioxide is low, which is suitable for the treatment of materials with lighter pollution, at 80°C, the solubility of carbon dioxide increases, which helps to accelerate cleaning and foaming, but easily affects material properties, reaction time of 30 minutes, suitable for waste materials with less impurities or lower pollution, at higher pressure and temperature, surface impurities can be quickly removed and foaming treatment can be carried out, reaction time of 2 hours: suitable for waste materials with heavier pollution, long-term treatment helps to completely remove stubborn impurities in the waste, and is more conducive to the uniform foaming of the foam structure, flow rate of 10 kg / h, suitable for the treatment of smaller-scale or low-pollution waste. When the flow rate is low, the effect of carbon dioxide is milder. The flow rate is 50 kg / h, suitable for large-scale production or heavily polluted waste. A higher flow rate can speed up the cleaning and foaming process of the waste and improve production efficiency. Preferably, the mass ratio of waste to carbon dioxide is 1:3 or 1:4.

[0021] Physical cleaning is any one of ultrasonic cleaning or high-pressure water jet cleaning.

[0022] The mixed material of step S4 is added with high temperature resistant toughening agent, heat stabilizer, antioxidant and foaming agent, the addition amount of toughening agent is 2%-10% of the mass of polystyrene, the toughening agent can improve the toughness of polystyrene foam, prevent the material from being brittle, and improve its impact resistance, the addition amount of heat stabilizer is 0.2%-1% of the mass of polystyrene, the toughening agent can improve the toughness of polystyrene foam, prevent the material from being brittle, and improve its impact resistance, the antioxidant is 0.1%-0.5% of the mass of polystyrene, the antioxidant can prevent polystyrene from oxidizing during thermal processing, reduce the breakage of molecular chains, and extend the service life of the material. Especially in high temperature and long-term processing, the antioxidant can effectively prevent the aging of the material, the foaming agent is 0.2%-1% of the mass of polystyrene, and the foaming agent is used to control the foaming effect of polystyrene foam, produce a uniform pore structure, thereby improving the lightness and heat insulation performance of the foam. The addition of foaming agent helps to control the density and hardness of the foam.

[0023] The proportion of waste in step S4 is 20%-60%. A lower waste proportion means that new materials account for a larger proportion, which can ensure the quality and performance of the final product. Impurities and quality fluctuations in the waste have less impact on product consistency. A higher waste proportion can effectively improve the utilization rate of raw materials, reduce the use of new materials, reduce production costs, and meet environmental protection requirements.

[0024] The extruder in step S4 is a twin-screw extruder, and the temperature control of the extruder is specifically as follows: the temperature of the feed section is 160°C-180°C, the temperature of the melting section is 180°C-220°C, the temperature of the metering section is 200°C-230°C, and the temperature of the extrusion die is 210°C-240°C. The twin-screw extruder has a high shear force, which can ensure uniform mixing of waste materials and new materials and prevent the problem of uneven bubbles.

[0025] The granulation process of this scheme uses recycled polystyrene waste as part of the raw materials, mixes the waste with new materials to manufacture new products, effectively improves the utilization rate of waste materials, reduces raw material costs, achieves higher resource recovery efficiency, solves the environmental pollution problem of waste materials, and complies with the concepts of circular economy and sustainable development. The waste materials are multiple cleansed before use to remove impurities and original auxiliary agent components on the waste materials. During the cleaning process, natural plant ingredients are used as solvents for soaking and cleaning, and the solvents are recycled and reused, reducing solvent waste and environmental pollution, effectively reducing resource waste and emissions in the production process, and no harmful gases are generated during the cleaning process, thereby improving production safety. After soaking and cleaning, supercritical carbon dioxide is used to foam the materials, which is helpful for environmental protection and reduces the use of traditional foaming agents. The products produced are mixed with waste materials and new materials to ensure the uniformity and performance of the products. During the mixing and melting process, a variety of additives are added to avoid product performance problems caused by waste quality. Example

[0026] In this embodiment, the process steps are the same as those of Example 1, except that when the ratio of waste materials to new materials is low, the addition of heat stabilizer is eliminated and the new materials account for a larger proportion, which can ensure the performance of the new product, reduce the addition of chemical additives, and also reduce certain costs.

[0027] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0028] The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Although the present invention has been disclosed as above in the form of preferred embodiments, it is not intended to limit the present invention. Any technical personnel in the field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A polystyrene foam granulation process, characterized in that: The specific steps include: Step S1, collecting waste polystyrene foam plastics and performing preliminary physical cleaning; Step S2, crushing the waste polystyrene foam plastics cleaned in step S1 into particles, soaking and cleaning them with a solvent, and recycling the solvent; Step S3, adding the soaked and cleaned waste to a supercritical carbon dioxide reactor to further remove impurities in the waste; Step S4, the waste material processed in step S3 is mixed with the new material to melt into a mixed material, and the melted mixed material is filtered, and the filtered mixed material is extruded through an extruder; Step S5, the extruded material is cooled and then cut into uniform particles by a pelletizer.

2. A polystyrene foam granulation process according to claim 1, characterized in that: The solvent is orange peel essential oil extract or any one of ethyl acetate and butanone, and the concentration of the solvent is 10%-100%.

3. A polystyrene foam granulation process according to claim 1, characterized in that: In step S2, the soaking and cleaning temperature is 25° C.-40° C. and the soaking time is 30 min-2 h.

4. A polystyrene foam granulation process according to claim 1, characterized in that: The parameters of the supercritical carbon dioxide reactor in step S3 are specifically as follows: pressure of 8-15 MPa, temperature of 30° C.-80° C., reaction time of 30 min-2 h, carbon dioxide flow rate of 10 kg-50 kg / h, and mass ratio of waste to carbon dioxide of 1:2-5.

5. A polystyrene foam granulation process according to claim 1, characterized in that: The physical cleaning is any one of ultrasonic cleaning or high-pressure water jet cleaning.

6. A polystyrene foam granulation process according to claim 1, characterized in that: The mixed material of step S4 is added with a high temperature resistant toughening agent, a heat stabilizer, an antioxidant and a foaming agent, wherein the toughening agent is added in an amount of 2%-10% of the mass of polystyrene, the heat stabilizer is added in an amount of 0.2%-1% of the mass of polystyrene, the antioxidant is added in an amount of 0.1%-0.5% of the mass of polystyrene, and the foaming agent is added in an amount of 0.2%-1% of the mass of polystyrene.

7. A polystyrene foam granulation process according to claim 1, characterized in that: The proportion of waste in step S4 is 20%-60%.

8. A polystyrene foam granulation process according to claim 1, characterized in that: The extruder in step S4 is a twin-screw extruder, and the temperature control of the extruder is specifically as follows: the temperature of the feeding section is 160°C-180°C, the temperature of the melting section is 180°C-220°C, the temperature of the metering section is 200°C-230°C, and the temperature of the extrusion die is 210°C-240°C.

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